AU2025238122A1

AU2025238122A1 - Heat-sealable paper and packaging bag

Info

Publication number: AU2025238122A1
Application number: AU2025238122A
Authority: AU
Inventors: Moeka NAMIOKA; Yasutomo Noishiki; Yuta SHAMOTO; Misaki WAKABAYASHI
Original assignee: Oji Holdings Corp
Current assignee: Oji Holdings Corp
Priority date: 2022-06-14
Filing date: 2025-09-29
Publication date: 2025-10-23
Also published as: AU2023290887B2; WO2023243642A1; AU2023290887A1; EP4541967A1; CN119343498A

Abstract

- 40 - Heat-sealable paper including one or more heat-sealable layers on at least one surface of a paper substrate, wherein the heat-sealable layer contains a water-dispersible resin binder, a longitudinal and transverse geometric mean of a tear index of the heat-sealable paper is 10 mNm2/g or more, a burst index of the heat-sealable paper is 3.0 kPam2/g or more, and when two such heat-sealable layers are heat-sealed to each other at 150C and 0.2 MPa for one second, a heat sealing peel strength is 2.0 N/15 mm or more and 10 N/15 mm or less. - 40 -

Description

DESCRIPTION DESCRIPTION

Title ofof Title Invention: HEAT-SEALABLE Invention: PAPER HEAT-SEALABLE PAPERAND AND PACKAGING BAG PACKAGING BAG

Technical Field Technical Field

[0001]

Thepresent The present invention invention relates relates to to heat-sealable heat-sealablepaper paper and and aapackaging packaging bag using the bag using the heat-sealable paper. heat-sealable paper.

Background Art Background Art

[0002]

Packagesusing Packages usingaaheat heat sealing sealing method methodhave havebeen been widely widely used used forfor packaging packaging foods, foods,

medicines, medical devices, etc., other than packaging general industrial products. medicines, medical devices, etc., other than packaging general industrial products.

[0003]

In recentyears, In recent years,the theproblem problem of plastic of plastic waste waste is getting is getting worse.worse. Of theplastic Of the world's world's plastic production amount, the packaging sector accounts for a large portion of the plastic production production amount, the packaging sector accounts for a large portion of the plastic production

amount,which amount, whichisisone oneofofthe the causes causes of of plastic plastic waste. Plastics do waste. Plastics donot not decompose decompose semi- semi-

permanently,and permanently, andtheir their garbage garbageturns turns into into microplastics microplastics in in the the natural naturalenvironment, environment, which has which has

aa serious serious adverse adverse effect effecton on the theecosystem. ecosystem. AsAs a a countermeasure, countermeasure, it it hasbeen has beenproposed proposed to to

replace plastics with paper. replace plastics with paper.

[0004]

For example, For example,JPJP2022-024664 2022-024664 A discloses A discloses water-resistant,oil-resistant, water-resistant, oil-resistant, heat-sealable heat-sealable

paper that contains a coating layer containing a thermoplastic resin, a wax, and a pigment on paper that contains a coating layer containing a thermoplastic resin, a wax, and a pigment on

at at least least one surfaceofofa apaper one surface paper substrate, substrate, for for the the purpose purpose of providing of providing water-resistant, water-resistant, oil- oil- resistant, heat-sealable paper that has water resistance, oil resistance, and the heat sealing resistant, heat-sealable paper that has water resistance, oil resistance, and the heat sealing

suitability andcan suitability and canbebestored stored forfor a long a long period period of time. of time.

Summary ofInvention Summary of Invention

[0005]

Theheat-sealable The heat-sealable paper paper described describedin in JP JP 2022-024664 2022-024664 has has an an excellentblocking excellent blocking resistance. However, resistance. However, tearing tearing ofof a abag bagduring duringtransportation transportationororease easeofofopening openingatatthe the time timeof of opening are not opening are not discussed. discussed.

[0006]

An object of the present invention is to provide heat-sealable paper that can achieve a An object of the present invention is to provide heat-sealable paper that can achieve a

packaging bag that is difficult to tear and can be easily opened at the time of opening, and a packaging bag that is difficult to tear and can be easily opened at the time of opening, and a

packagingbag packaging bagincluding includingthe theheat-sealable heat-sealablepaper. paper.

[0007]

Theobject The object of of the the present present invention invention can can be be achieved by the achieved by the following configurations following configurations

<1>to <1> to <17>. <17>. <1>Heat-sealable <1> Heat-sealablepaper papercomprising comprising one one or or more more heat-sealable heat-sealable layers layers onon at at leastone least onesurface surface of a paper substrate, wherein of a paper substrate, wherein

the heat-sealable layer comprises a water-dispersible resin binder, the heat-sealable layer comprises a water-dispersible resin binder,

aa longitudinal and longitudinal and transverse transverse geometric geometric mean mean of ofindex a tear a tearofindex of the heat-sealable the heat-sealable paper paper 2 or more, is 10 is 10 mNm mN.m²/g/g or more, aa burst indexofofthe burst index theheat-sealable heat-sealable paper paper is kPa.m²/g is 3.0 3.0 kPamor 2more, /g or and more, and whentwo when twosuch suchheat-sealable heat-sealablelayers layersare areheat-sealed heat-sealed to to each each other other at at 150C and0.2 150°C and 0.2 MPa MPa for one for one second, second, a a heat heat sealing sealing peel peelstrength strengthisis 2.02.0 N/15 N/15mm mm or or more and 10 more and 10N/15 N/15mmmm or or less. less.

<2>The <2> Theheat-sealable heat-sealablepaper paperaccording accordingtoto<1>, <1>,wherein wherein theheat-sealable the heat-sealablelayer layerfurther further comprises a lubricant. comprises a lubricant.

<3>The <3> Theheat-sealable heat-sealablepaper paperaccording accordingtoto<2>, <2>,wherein wherein thelubricant the lubricantcomprises comprisesat at leastone least one selected selected from the group from the consisting of group consisting of paraffin paraffin wax, wax, carnauba wax,and carnauba wax, andpolyolefin polyolefinwax. wax. <4>The <4> Theheat-sealable heat-sealablepaper paperaccording accordingtoto<2> <2>oror<3>, <3>,wherein wherein a content a content of of thelubricant the lubricantinin the heat-sealable the heat-sealable layer layerisis1% 1% by by mass mass or or more and5% more and 5%bybymass mass or or less. less.

<5>The <5> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1>toto <4>, <4>, wherein wherein a glass a glass transition transition

temperature of the water-dispersible resin binder is 0C or more and 100C or less. temperature of the water-dispersible resin binder is 0°C or more and 100°C or less.

<6>The <6> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1>toto <5>, <5>, wherein wherein thethe water- water-

dispersible resin binder comprises at least one selected from the group consisting of a styrene- dispersible resin binder comprises at least one selected from the group consisting of a styrene-

butadiene copolymer butadiene copolymerand and anan olefin-unsaturatedcarboxylic olefin-unsaturated carboxylic acidcopolymer. acid copolymer. <7>The <7> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<2> <2>toto <6>,wherein <6>, wherein thethe water- water-

dispersible resin dispersible resinbinder bindercomprises comprises a a styrene-butadiene styrene-butadiene copolymer, andthe copolymer, and thelubricant lubricant comprises comprises paraffin wax. paraffin wax.

<8>The <8> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<2> <2>toto <6>, <6>, wherein wherein thethe water- water-

dispersible resin dispersible resinbinder bindercomprises comprises an an olefin-unsaturated olefin-unsaturated carboxylic carboxylic acid acid copolymer, andthe copolymer, and the lubricant comprises lubricant carnaubawax. comprises carnauba wax. <9>The <9> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1>toto <8>, <8>, wherein wherein Canadian Canadian standard standard

freeness of freeness of pulp pulp constituting constitutingthe thepaper papersubstrate substrateisis 500 mL 500 mL or ormore more and and 750 mLororless. 750 mL less. <10>The <10> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1> to to <9>, <9>, wherein wherein a main a main component component

of pulp constituting the paper substrate is needle unbleached kraft pulp. of pulp constituting the paper substrate is needle unbleached kraft pulp.

<11>The <11> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1> to to <10>, <10>, wherein wherein a value a value (Clark (Clark

stiffness/basis stiffness/basisweight) weight)obtained obtained by by dividing dividing aalongitudinal longitudinaland andtransverse transversegeometric geometric mean of mean of

Clark stiffness of the heat-sealable paper by a basis weight (g/m²) of the2 heat-sealable paper is Clark stiffness of the heat-sealable paper by a basis weight (g/m ) of the heat-sealable paper is 0.20 m2/g or 0.20 m²/g or more moreand and1.20 m2/gororless. 1.20m²/g less. <12>The <12> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1> to to <11>, <11>, wherein wherein a piercing a piercing

strength ofthe strength of theheat-sealable heat-sealable paper paper is 10.0 is 10.0 N or N or more. more.

<13>The <13> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1> to to <12>, <12>, wherein wherein a basis a basis weight weight of of the paper substrate is 50 g/m² or2 more and 150 g/m² or less. the paper substrate is 50 g/m or more and 150 g/m or less. 2

<14>The <14> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1> to to <13>, <13>, wherein wherein a basis a basis weight weight of of the heat-sealable layer is 3 g/m² or2 more and 30 g/m² or less. the heat-sealable layer is 3 g/m or more and 30 g/m or less. 2

<15>The <15> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1> to to <14>, <14>, wherein wherein a basis a basis weight weight of of the heat-sealable paper is 50 g/m² or 2more and 200 g/m² or less.2 the heat-sealable paper is 50 g/m or more and 200 g/m or less. <16>The <16> Theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofof<1> <1> to to <15>, <15>, wherein wherein the the paper paper

substrate is extensible substrate is extensiblepaper. paper. <17>AApackaging <17> packagingbagbag using using thethe heat-sealable heat-sealable paper paper according according to to any any oneone of of <1><1> to to <16>. <16>.

Description of Description of Embodiments Embodiments

[0008]

Hereinafter, the Hereinafter, the preferable preferable embodiments ofthe embodiments of the present present invention invention will will be be described. described.

In this In thisdescription, description,"X "XtotoY" Y"showing showing a a range range means means aa range rangeof of "X "Xorormore moreand andY Y oror less". less".

Whennumerical When numerical ranges ranges areare statedstepwise, stated stepwise,the theupper upperand andlower lower limitsofofeach limits eachnumerical numerical range can range can be be combined combinedarbitrarily. arbitrarily. InInthis thisdescription, description, unless unless otherwise otherwise specified, specified, operations operations

and measurements and measurements of of physicalproperties physical propertiesand andthe thelike likeare are performed performedunder underthetheconditions conditionsofof roomtemperature room temperature(20 (20toto25°C)/relative 25C)/relativehumidity humidityofof4040toto50%RH. 50%RH. Further, Further, the term the term

"(meth)acrylic" collectively "(meth)acrylic" collectively refers refers to acrylic to acrylic and and methacrylic. methacrylic.

[0009]

<Heat-sealable paper> <Heat-sealable paper>

Heat-sealable paper Heat-sealable paper of of the the present present embodiment (hereinafter,simply embodiment (hereinafter, simplyreferred referredto to as as "heat-sealable paper") "heat-sealable paper") includes includes onemore one or or more heat-sealable heat-sealable layers onlayers on one at least at least oneofsurface surface a of a paper substrate, wherein the heat-sealable layer comprises a water-dispersible resin binder, a paper substrate, wherein the heat-sealable layer comprises a water-dispersible resin binder, a

longitudinal and transverse geometric mean of a tear index of the heat-sealable paper is 10 longitudinal and transverse geometric mean of a tear index of the heat-sealable paper is 10

mNm2/gorormore, mN.m²/g more,a aburst burstindex indexofofthe theheat-sealable heat-sealable paper paperis is 3.0 3.0 kPam 2 or more, and when /g or more, and when kPa.m²/g

two such two suchheat-sealable heat-sealable layers layers are are heat-sealed heat-sealed to toeach each other otheratat150C 150°C and and 0.2 0.2 MPa for one MPa for one second, a heat second, a heat sealing sealing peel peel strength strengthisis 2.0 N/15 2.0 N/15mm or more mm or and10 more and 10N/15 N/15mmmm or less. or less.

According to the heat-sealable paper of the present embodiment, it is possible to obtain a According to the heat-sealable paper of the present embodiment, it is possible to obtain a

packaging bag that is difficult to tear and can be easily opened at the time of opening. packaging bag that is difficult to tear and can be easily opened at the time of opening.

[0010]

The water-dispersible resin binder is used to form a heat-sealable layer, which makes it The water-dispersible resin binder is used to form a heat-sealable layer, which makes it

possible to achieve the heat sealing property. In addition, it is thought that when heat- possible to achieve the heat sealing property. In addition, it is thought that when heat-

sealable paper sealable paper has has a a longitudinal longitudinal and and transverse transverse geometric geometric mean ofaa tear mean of tear index index of of 10 10

mNm2/gorormore, mN.m²/g more,thetheheat-sealable heat-sealablepaper papercan canwithstand withstandshearing shearing due due to to drop drop oror deformation deformation

during transportation and is difficult to tear. Moreover, it is thought that when heat-sealable during transportation and is difficult to tear. Moreover, it is thought that when heat-sealable

2 paper has paper has aa burst burst index index of of 3.0 3.0 kPam kPa-m²/g/g or or more, a packaging more, a bagobtained packaging bag obtainedfrom fromthe theheat- heat- sealable paper is prevented from being torn due to drop or the like during transportation. sealable paper is prevented from being torn due to drop or the like during transportation. In In addition, it is thought that when heat-sealable paper has a heat sealing peel strength of 2.0 addition, it is thought that when heat-sealable paper has a heat sealing peel strength of 2.0

N/15mm N/15 mmor or more, more, a heat-sealedportion a heat-sealed portionisisprevented preventedfrom from being being damaged damaged due due to drop to drop or or the the like during transportation, and when the heat-sealable paper has a heat sealing peel strength of like during transportation, and when the heat-sealable paper has a heat sealing peel strength of

10 N/15 mm N/15 mm oror less,opening less, openingisiseasily easily performed. performed.Note Note that, that, thetheeffect effectofofthe the present present invention is not invention is not limited limitedby bythe theabove above mechanism. mechanism. In In thethe present present specification,the specification, the longitudinal direction of the heat-sealable paper means a direction corresponding to a longitudinal direction of the heat-sealable paper means a direction corresponding to a

papermaking direction (MD direction) of a paper substrate, and the transverse direction of the papermaking direction (MD direction) of a paper substrate, and the transverse direction of the

heat-sealable paper heat-sealable paper means means aadirection direction corresponding correspondingtotoaa width widthdirection direction (CD (CDdirection) direction) of of the the paper substrate. paper substrate.

[0011]

[Paper substrate]

(Raw materialpulp) (Raw material pulp) The pulp constituting the paper substrate is not particularly limited, and known pulps The pulp constituting the paper substrate is not particularly limited, and known pulps

can be can be used. used. Specifically, Specifically,examples examples thereofinclude thereof includeunbleached unbleached pulps pulps such such as as Leaf Leaf

UnbleachedKraft Unbleached KraftPulp Pulp(LUKP) (LUKP) and and Needle Needle Unbleached Unbleached Kraft Kraft Pulp (NUKP); Pulp (NUKP); chemicalchemical pulps pulps such as Leaf such as BleachedKraft Leaf Bleached KraftPulp Pulp(LBKP) (LBKP)andand Needle Needle Bleached Bleached KraftKraft Pulp Pulp (NBKP); (NBKP);

mechanicalpulps mechanical pulpssuch suchasasGroundwood GroundwoodPulpPulp (GP), (GP), Pressurized Pressurized Groundwood Groundwood Pulp Pulp (PGW), (PGW), Refiner Mechanical Refiner Mechanical Pulp Pulp(RMP), (RMP), ThermoMechanical Pulp (TMP), ThermoMechanical Pulp (TMP), ChemiThermoMechanical ChemiThermoMechanical

Pulp (CTMP), Pulp ChemiMechanicalPulp (CTMP), ChemiMechanical Pulp(CMP), (CMP),and andChemiGroundwood ChemiGroundwood Pulp Pulp (CGP); (CGP); waste waste

paper pulps; paper pulps; non-wood fiberpulps non-wood fiber pulpssuch suchasaskenaf, kenaf,bagasse, bagasse,bamboo, bamboo, and and cotton; cotton; and and synthetic synthetic

pulps. These pulps. These pulps pulps maymay be used be used individually individually by one by one typetype or combination or in in combination of two of two or more or more

types. Among types. Among them, them, at least at least oneone selected selected from from thethe group group consisting consisting of of Leaf Leaf Unbleached Unbleached

Kraft Kraft Pulp (LUKP),Needle Pulp (LUKP), Needle Unbleached Unbleached Kraft Kraft PulpPulp (NUKP), (NUKP), Leaf Bleached Leaf Bleached Kraft Pulp Kraft Pulp

(LBKP), andNeedle (LBKP), and Needle Bleached Bleached Kraft Kraft Pulp Pulp (NBKP) (NBKP) is preferable, is preferable, at least at least oneone selected selected from from thethe

group consisting group consisting of of Leaf UnbleachedKraft Leaf Unbleached KraftPulp Pulp(LUKP) (LUKP) and and Needle Needle Unbleached Unbleached Kraft Kraft Pulp Pulp

(NUKP) (NUKP) isismore more preferable,and preferable, andNeedle Needle Unbleached Unbleached Kraft Kraft PulpPulp (NUKP) (NUKP) is still is still moremore

preferable. preferable.

[0012]

A main A maincomponent componentof of pulp pulp constituting constituting thepaper the paper substrateused substrate usedininthe theheat-sealable heat-sealable paper of paper of the the present present embodiment embodiment isispreferably preferablysoftwood softwoodpulp, pulp,and andisismore morepreferably preferablyNeedle Needle UnbleachedKraft Unbleached KraftPulp Pulp(NUKP). (NUKP). The "main The "main component component of pulp constituting of pulp constituting the the paper paper substrate is softwood substrate is softwood pulp" pulp" means means thatcontent that the the content of softwood of softwood pulp pulp in pulp in pulp constituting constituting the the paper substrate paper substrate is ismore more than than 50% bymass, 50% by mass,and andthe thecontent contentofofthe thesoftwood softwoodpulp pulpisispreferably preferably 80% bymass 80% by massoror more, more, more more preferably preferably 90%90% by mass by mass or more, or more, and still and still moremore preferably preferably 100%100%

by mass. by mass. Similarly, Similarly,thethe"main "main component component of pulp of pulp constituting constituting the the paper paper substrate substrate is is needle needle

unbleachedkraft unbleached kraft pulp" pulp" means meansthat thatthe the content content of of needle needle unbleached unbleachedkraft kraftpulp pulpinin pulp pulp constituting the constituting the paper paper substrate substrateisis more morethan than50% 50% by mass, and by mass, andthe the content content of of the the needle needle

unbleachedkraft unbleached kraft pulp pulp is is preferably preferably 80% bymass 80% by massorormore, more,more more preferably preferably 90%90% by mass by mass or or more, and more, andstill still more more preferably preferably 100% bymass. 100% by mass.The The average average fiberfiber length length of softwood of softwood pulp pulp is is long, and use of a paper substrate containing softwood pulp as raw material pulp is preferable long, and use of a paper substrate containing softwood pulp as raw material pulp is preferable

becauseheat-sealable because heat-sealable paper paper that that has has desirable desirable tear tearindex indexand and burst burstindex indexcan can be be obtained. In obtained. In

addition, use addition, use of of Needle Needle Unbleached KraftPulp Unbleached Kraft Pulp(NUKP) (NUKP) as pulp as pulp constituting constituting a paper a paper substrate substrate

is advantageous because the strength of the pulp fiber itself is higher than that of Needle is advantageous because the strength of the pulp fiber itself is higher than that of Needle

BleachedKraft Bleached KraftPulp Pulp(NBKP) (NBKP) or Leaf or Leaf Unbleached Unbleached KraftKraft Pulp Pulp (LUKP), (LUKP), andthe and thus thus the obtained obtained

paper substrate has higher strength and elongation. paper substrate has higher strength and elongation.

[0013]

Thesoftwood The softwoodpulp pulpisispreferably preferablypulp pulpobtained obtainedfrom fromatatleast least one one or or more moreselected selected from from the group the consisting of group consisting of Douglas fir and Douglas fir and pine pine tree, tree,and andisismore morepreferably preferablypulp pulpobtained obtained from from

Douglasfir, Douglas fir, from the viewpoint from the of obtaining viewpoint of obtaining heat-sealable heat-sealable paper paper having desirable tear having desirable tear index index

and burstindex. and burst index.

[0014]

Theraw The rawmaterial materialpulp pulpconstituting constituting the the paper substrate preferably paper substrate preferably contains contains one one or or more more

selected from selected the group from the consisting of group consisting of bleached kraft pulp bleached kraft pulp and and unbleached kraft pulp, unbleached kraft pulp, and more and more

preferably contains preferably contains unbleached kraft pulp. unbleached kraft pulp.

[0015]

(Canadian standardfreeness) (Canadian standard freeness) The beating degree of the raw material pulp constituting the paper substrate is not The beating degree of the raw material pulp constituting the paper substrate is not

specifically limited. specifically Fromthe limited. From theviewpoint viewpointofofobtaining obtainingheat-sealable heat-sealablepaper paperhaving havingdesirable desirable tear index tear index and and burst burst index, index, the theCanadian Canadian standard freeness (CSF) standard freeness is preferably (CSF) is preferably 500 mLoror 500 mL

moreand more andmore morepreferably preferably550 550 mLmL or more, or more, and and is preferably is preferably 750750 mL mL or less or less and and moremore preferably 700 preferably mLororless. 700 mL less. Moreover, Moreover, the the smoothness smoothness of the of the surface surface of paper of paper becomes becomes good good and the printability can be maintained. and the printability can be maintained.

TheCSF The CSFisismeasured measured according according to to JISJIS P P 8121-2:2012 8121-2:2012 "Pulp-Freeness "Pulp-Freeness test test method- method-

Chapter2: Chapter 2: Canadian Canadianstandard standardfreeness freenessmethod". method".

[0016]

(Kappa number) (Kappa number)

Thepulp The pulpconstituting constituting the the paper paper substrate substrate preferably preferably has has aakappa kappa number as measured number as measured in accordance in with JIS accordance with JIS PP 8211:2011 8211:2011ofof3030orormore, more,and andpreferably preferably6060ororless, less,more morepreferably preferably 55 orless, 55 or less, further furtherpreferably preferably50 50 or or less, less, further further preferably preferably 46 or46 or less, less, for obtaining for obtaining heat- heat-

sealable paper sealable paper having impactresistance having impact resistance and and workability. workability. TheThe kappa kappa number number of pulp of the the pulp constituting the constituting the paper paper substrate substrateisis measured measured in inaccordance accordance with with JIS JIS P P 8211:2011, usingaa 8211:2011, using

paper substrate paper substrate pulp pulp disintegrated disintegrated in inaccordance accordance with with JIS JIS P P 8220-1:2012 asaa sample. 8220-1:2012 as sample.

[0017]

(Basis (Basis weight) weight)

The basis weight of the paper substrate is not specifically limited, but is preferably 50 The basis weight of the paper substrate is not specifically limited, but is preferably 50

g/m2 or g/m² or more, more, more morepreferably preferably6060g/m² 2 more, and still more preferably 70 g/m² or g/moror more, and still more preferably 70 g/m2 ormore, more, and is preferably and is preferably150150 g/m² or 2less, g/m or less, moremore preferably preferably 120 120 g/m² less,2 still or g/m or less, still more more preferably preferably 110 110 g/m² 2or less, and even still more preferably 100 g/m² or less, 2 from the viewpoint of obtaining g/m or less, and even still more preferably 100 g/m or less, from the viewpoint of obtaining heat-sealable paper heat-sealable paper having desirable tear having desirable tear index index and and burst burst index. Thebasis index. The basisweight weightofofthe the paper substrate paper substrate is ismeasured in accordance measured in withJIS accordance with JISPP8124:2011. 8124:2011.

[0018]

(Thickness) (Thickness)

Thethickness The thickness of of the the paper substrate isispreferably paper substrate 60m preferably60 µm or or more, more, more preferably80 more preferably 80 m ormore, µm or more,and andstill still more preferably 100 more preferably morormore, 100µm more,andand isispreferably 200µmm preferably200 or or less, less,

morepreferably more 180µmm preferably180 or or less,and less, andstill still more preferably 160 more preferably mororless, 160 µm less, from fromthe the viewpoint viewpoint of obtaining of obtaining heat-sealable heat-sealable paper paper having desirable tear having desirable tear index index and and burst burst index. Thethickness index. The thickness of the of the paper paper substrate substrate isismeasured measured in in accordance with JIS accordance with JIS P P 8118:2014. 8118:2014.

[0019]

(Density) (Density) 3 or more and more preferably Thedensity The density of of the the paper paper substrate substrate is ispreferably preferably0.3 0.3g/cm g/cm³or more and more preferably 3 more, and is preferably 1.0 g/cm³ or less, 3 3 0.5 g/cm or more, and is preferably 1.0 g/cm or less, more preferably 0.9 g/cm or less, and 0.5 g/cm³ or more preferably 0.9 g/cm³ or less, and

still stillmore preferably0.75 more preferably 0.75 g/cm³ or 3less, g/cm or less, fromfrom the viewpoint the viewpoint of obtaining of obtaining heat-sealable heat-sealable paper paper having desirable having desirable tear tear index index and and burst burst index index and and from the viewpoint from the viewpointofof formability. formability. TheThe density of the paper substrate is calculated from the basis weight and the thickness of the density of the paper substrate is calculated from the basis weight and the thickness of the

paper substrate paper substrate obtained obtained by the aforementioned by the measurement aforementioned measurement methods. methods.

[0020]

(Optional components) (Optional components)

Thepaper The papersubstrate substrate may maycontain containoptional optionalcomponents components including including internal internal additivessuch additives such as anionic,cationic, as anionic, cationic,ororamphoteric amphoteric retention retention aids,aids, drainage drainage aids, aids, dry drystrength paper paper strength additives, additives,

wet paper strength additives, sizing agents, fixing agents, and fillers, waterproofing agents, wet paper strength additives, sizing agents, fixing agents, and fillers, waterproofing agents,

dyes, and fluorescent whitening agents, as required. dyes, and fluorescent whitening agents, as required.

[0021]

Examplesofofthe Examples thedry drypaper paperstrength strengthadditives additivesinclude includecationized cationizedstarch, starch, polyacrylamide, polyacrylamide,

carboxymethylcellulose, carboxymethylcellulose and and thethe like.TheThe like. content content of the of the drydry paper paper strength strength additives additives is is not not

specifically limited and is preferably 3.0 mass% or less per raw material pulp (absolute dry specifically limited and is preferably 3.0 mass% or less per raw material pulp (absolute dry

mass). mass).

[0022]

Examplesofofthe Examples thewet wetpaper paperstrength strengthadditives additivesinclude includepolyamide polyamidepolyamine polyamine epichlorohydrin, urea epichlorohydrin, urea formaldehyde formaldehyderesin, resin,melamine melamine formaldehyde formaldehyde resin, resin, andand the the like.The like. The content of the wet paper strength additive is not specifically limited, but is preferably 3.0% by content of the wet paper strength additive is not specifically limited, but is preferably 3.0% by

mass or less per raw material pulp (absolute dry mass). mass or less per raw material pulp (absolute dry mass).

[0023]

Examples of the sizing agents include internal sizing agents such as rosin sizing agents, Examples of the sizing agents include internal sizing agents such as rosin sizing agents,

synthetic sizingagents, synthetic sizing agents, petroleum petroleum resinresin sizing sizing agents, agents, and and the theand like, like, and surface surface sizing agents sizing agents

such as styrene/acrylic such as styrene/acrylic acid acidcopolymers, copolymers, styrene/methacrylic acid copolymers, styrene/methacrylic acid copolymers,and andthe thelike. like. The content of the sizing agents is not specifically limited and is preferably 3.0 mass% or less The content of the sizing agents is not specifically limited and is preferably 3.0 mass% or less

per raw per material pulp raw material pulp (absolute (absolute dry dry mass). mass).

[0024]

Examplesofoffixing Examples fixingagents agentsinclude includealuminum aluminum sulfate,polyethyleneimine, sulfate, polyethyleneimine, andand thethe like. like.

The content of the fixing agents is not specifically limited and is preferably 3.0 mass% or less The content of the fixing agents is not specifically limited and is preferably 3.0 mass% or less

[0025]

Examples of the fillers include inorganic fillers such as talc, kaolin, calcined kaolin, Examples of the fillers include inorganic fillers such as talc, kaolin, calcined kaolin,

calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina,

magnesium magnesium carbonate, carbonate, magnesium magnesium oxide, oxide, silica, silica, white white carbon, carbon, bentonite, bentonite, zeolite,sericite, zeolite, sericite, and and

smectite, andorganic smectite, and organic fillers fillers such such as acrylic as acrylic resins resins and vinylidene and vinylidene chloride chloride resins. resins.

[0026]

As the As the paper paper substrate, substrate, Clupak paper (extensible Clupak paper (extensible paper) paper) or or the the like likewhich which has has been been

subjected to Clupak subjected to processingfor Clupak processing for shrinking shrinking paper paperstrip strip may be used, may be used, for for example. example. TheThe

extensible paper refers to paper that has an elongation in the longitudinal direction or in the extensible paper refers to paper that has an elongation in the longitudinal direction or in the transverse direction transverse direction of of5% 5% or or more measuredaccording more measured according to to JISP P8113:2006, JIS 8113:2006,andand examples examples thereof include thereof include kraft kraftpaper paper type-5 type-5 Nos. Nos. 11 and and 2 2 described described in in JIS JIS PP 3401:2000. The 3401:2000. The paper paper substrate is preferably substrate is preferablyClupak Clupak paper paper (extensible (extensible paper) paper) from thefrom the viewpoint viewpoint ofheat- of obtaining obtaining heat- sealable paperhaving sealable paper having desirable desirable ClarkClark stiffness stiffness and piercing and piercing strength. strength.

[0027]

[Heat-sealable layer]

Theheat-sealable The heat-sealable paper paper according accordingtoto this this embodiment comprises embodiment comprises at at leastone least oneheat- heat- sealable layer on at least one surface of the paper substrate. The heat-sealable layer is a sealable layer on at least one surface of the paper substrate. The heat-sealable layer is a

layer that is melted and adheres by heating, ultrasonic waves, or the like. layer that is melted and adheres by heating, ultrasonic waves, or the like.

[0028]

(Water-dispersible resin binder) (Water-dispersible resin binder)

Theheat-sealable The heat-sealable layer layer contains contains a a water-dispersible water-dispersible resin resinbinder. Thewater- binder. The water- dispersible resin binder is a resin binder that is not water-soluble (specifically, the solubility dispersible resin binder is a resin binder that is not water-soluble (specifically, the solubility

in water at 25C is 10 g/L or less) but is finely dispersed in water like an emulsion or a in water at 25°C is 10 g/L or less) but is finely dispersed in water like an emulsion or a

suspension. Aqueous suspension. Aqueous application application of the of the heat-sealable heat-sealable layer layer using using a water-dispersibleresin a water-dispersible resin binder enables heat-sealable paper that is excellent in re-disintegration property and can be binder enables heat-sealable paper that is excellent in re-disintegration property and can be

recycled as recycled as paper to be paper to be obtained. obtained. InInthe thecase casewhere wherethe thewater-dispersible water-dispersibleresin resin binder binder also also corresponds to the following lubricant, it is classified as a lubricant. corresponds to the following lubricant, it is classified as a lubricant.

[0029]

The water-dispersible resin binder is not specifically limited, as long as it exerts the The water-dispersible resin binder is not specifically limited, as long as it exerts the

effects of the present invention, but examples thereof include polyolefin resins (such as effects of the present invention, but examples thereof include polyolefin resins (such as

polyethylene and polypropylene), vinyl chloride resins, styrene resins, styrene-butadiene polyethylene and polypropylene), vinyl chloride resins, styrene resins, styrene-butadiene

copolymers,styrene-unsaturated copolymers, styrene-unsaturatedcarboxylic carboxylicacid acidcopolymers copolymers (such (such as as styrene-(meth)acrylic styrene-(meth)acrylic

acid copolymer), acrylic resins, acrylonitrile-styrene copolymers, acrylonitrile-butadiene acid copolymer), acrylic resins, acrylonitrile-styrene copolymers, acrylonitrile-butadiene

copolymers,ABS copolymers, ABS resins,AAS resins, AAS resins, resins, AESAES resins, resins, vinylidene vinylidene chloride chloride resins,polyurethane resins, polyurethane resins, poly-4-methyl pentene-1 resins, polybutene-1 resins, vinylidene fluoride resins, vinyl resins, poly-4-methyl pentene-1 resins, polybutene-1 resins, vinylidene fluoride resins, vinyl

fluoride resins, fluorine resins, polycarbonate resins, polyamide resins, acetal resins, fluoride resins, fluorine resins, polycarbonate resins, polyamide resins, acetal resins,

polyphenyleneoxide polyphenylene oxideresins, resins,polyester polyester resins resins (such (such as as polyethylene terephthalate and polyethylene terephthalate and

polybutyleneterephthalate), polybutylene terephthalate), polyphenylene sulfide resins, polyphenylene sulfide resins, polyimide resins, polysulfone polyimide resins, polysulfone

resins, polyether sulfone resins, polyarylate resins, olefin-unsaturated carboxylic acid resins, polyether sulfone resins, polyarylate resins, olefin-unsaturated carboxylic acid

copolymers,and copolymers, andmodified modifiedproducts products thereof.These thereof. These may may be used be used individually individually bytype by one one or type or maybebeused may usedinincombination combinationofoftwo two typesorormore. types more. Among these, the heat-sealable layer preferably includes at least one selected from the Among these, the heat-sealable layer preferably includes at least one selected from the

group consisting group consisting of of aa styrene-butadiene copolymerand styrene-butadiene copolymer andananolefin-unsaturated olefin-unsaturatedcarboxylic carboxylicacid acid copolymer. copolymer.

Furthermore, the heat-sealable layer preferably includes an olefin-unsaturated Furthermore, the heat-sealable layer preferably includes an olefin-unsaturated

carboxylic acid carboxylic acid copolymer fromthetheviewpoint copolymer from viewpointof of increasingheat increasing heatsealing sealingpeel peelstrength, strength, and and morepreferably more preferablyincludes includesaa styrene-butadiene styrene-butadienecopolymer copolymer from from thethe viewpoint viewpoint of of availability, availability,

cost, and recyclability. cost, and recyclability.

[0030]

Examplesofofthe Examples theolefin-unsaturated olefin-unsaturatedcarboxylic carboxylicacid acidcopolymer copolymer include include anan ethylene- ethylene-

(meth)acrylic acid copolymer (meth)acrylic acid andananethylene-(meth)acrylic copolymer and ethylene-(meth)acrylicacid acidalkyl alkylester ester copolymer. copolymer. Among Among them, them, an an ethylene-(meth)acrylic ethylene-(meth)acrylic acid acid copolymer copolymer is preferably is preferably included, included, andand an an ethylene-acrylic acid ethylene-acrylic acid copolymer is more copolymer is morepreferably preferablyincluded. included. Therefore, the water-dispersible resin binder contained in the heat-sealable layer Therefore, the water-dispersible resin binder contained in the heat-sealable layer

preferably contains at least one selected from the group consisting of a styrene-butadiene preferably contains at least one selected from the group consisting of a styrene-butadiene

copolymerand copolymer andananethylene-(meth)acrylic ethylene-(meth)acrylic acidcopolymer. acid copolymer. Note Note that,that, the olefin-unsaturated the olefin-unsaturated

carboxylic acid carboxylic acid copolymer may copolymer may be be an an ionomer. ionomer.

[0031]

Thestyrene-butadiene The styrene-butadienecopolymer copolymermaymay be any be any of synthetic of synthetic product product andand commercially commercially

available product, available product, and and examples of the examples of the commercially commerciallyavailable availableproduct productinclude includeNipol Nipollatex latex LX407G51,LX407S10, LX407G51, LX407S10, LX407S12, LX407S12, LX410, LX410, LX415M, LX415M, LX416, LX416, LX430,LX430, LX433C, LX433C, 2507H, 2507H, available available from ZeonCorporation, from Zeon Corporation,Nalstar NalstarSR-101, SR-101, SR-102, SR-102, SR-103, SR-103, SR-115, SR-115, and SR-153, and SR-153,

available available from NIPPON from NIPPON A&LA&L INC.,INC., and styrene and styrene butadiene butadiene latex latex 0602 0602 and 0597C, and 0597C, available available

from JSR from JSRCorporation. Corporation.

[0032]

Theethylene-(meth)acrylic The ethylene-(meth)acrylicacid acidcopolymer copolymertoto bebe usedmaymay used be be anyany of of synthetic synthetic

products and products and commercially commercially availableproducts, available products,and andexamples examples of of thethe commercially commercially available available

products include products includeMP498345N, MP498345N, MP4983R, MP4990R, MP4983R, MP4990R, andand MFHS1279, MFHS1279, available available from from

MichelmanJapan Michelman Japan LLC, LLC,ZAIKTHENE ZAIKTHENE (registered (registered trademark)A Aand trademark) andZAIKTHENE ZAIKTHENE (registered (registered

trademark)AC, trademark) AC,available availablefrom fromSumitomo Sumitomo Seika Seika Chemicals Chemicals Company, Company, Limited, Limited, and and CHEMIPEARL CHEMIPEARL S Series, S Series, available available from from Mitsui Mitsui Chemicals, Chemicals, Inc. Inc.

[0033]

The glass transition temperature of the water-dispersible resin binder is preferably 0C The glass transition temperature of the water-dispersible resin binder is preferably 0°C

or more, or morepreferably more, more preferably10°C 10Corormore, more,and andstill still more morepreferably preferably15°C 15Corormore. more.WhenWhen the the water-dispersible resin water-dispersible resin binder binder having having a glass a glass transition transition temperature temperature that istoequal that is equal to or higher or higher

than the above lower limit is used, the blocking resistance of the heat-sealable paper can be than the above lower limit is used, the blocking resistance of the heat-sealable paper can be

improved.From improved. From the the viewpoint viewpoint of the of the heatheat sealing sealing property, property, thethe glass glass transitiontemperature transition temperature of the water-dispersible resin binder is preferably 100C or less, more preferably 80C or less, of the water-dispersible resin binder is preferably 100°C or less, more preferably 80°C or less,

still stillmore preferably60°C more preferably 60C or less, or less, and and even even still still more more preferably preferably 50°C or 50C less. or less.

10 --

As the glass transition temperature of the water-dispersible resin binder, a value As the glass transition temperature of the water-dispersible resin binder, a value

measured with a differential scanning calorimeter is used. measured with a differential scanning calorimeter is used.

[0034]

The content of the water-dispersible resin binder in the heat-sealable layer is preferably The content of the water-dispersible resin binder in the heat-sealable layer is preferably

30% 30% bybymass massoror more, more, more more preferably preferably 50%50% by mass by mass or more, or more, stillstill more more preferably preferably 70% 70% by by massor mass or more, more,and andeven evenstill still more preferably 80% more preferably 80%bybymass mass or or more, more, andand is is 100% 100% by mass by mass or or less, less,preferably preferably99% by mass 99% by massoror less, less, and and more preferably 98% more preferably 98%bybymass mass or or less.WhenWhen less. the the

content falls within the above range, the heat-sealable paper having a high heat sealing peel content falls within the above range, the heat-sealable paper having a high heat sealing peel

strength canbebeobtained. strength can obtained.

[0035]

That is, according to one embodiment of the present invention, the content of the That is, according to one embodiment of the present invention, the content of the

styrene-butadiene copolymerand/or styrene-butadiene copolymer and/orolefin-unsaturated olefin-unsaturatedcarboxylic carboxylicacid acidcopolymer copolymer (preferably (preferably

ethylene-(meth)acrylic acid ethylene-(meth)acrylic acid copolymer) copolymer)ininthe theheat-sealable heat-sealable layer layer is is preferably preferably 30% by mass 30% by mass or more, or morepreferably more, more preferably50% 50%byby mass mass or or more, more, stillmore still more preferably70%70% preferably by mass by mass or more, or more,

and even still and even still more more preferably preferably 90% bymass 90% by massorormore, more,and andisis100% 100%by by mass mass or less, or less, preferably preferably

99%bybymass 99% massoror less,and less, andmore morepreferably preferably98% 98% by by mass mass or less. or less. Here, Here, "content "content of A of A and/or and/or

B" refers to the content of A or B when only one of A and B is contained, or refers to the total B" refers to the content of A or B when only one of A and B is contained, or refers to the total

content of content of A and BBwhen A and whenboth bothA A andand B are B are contained. contained.

[0036]

(Lubricant) (Lubricant)

From the viewpoint of imparting the slip property and blocking resistance to the heat- From the viewpoint of imparting the slip property and blocking resistance to the heat-

sealable paper,thetheheat-sealable sealable paper, heat-sealable layer layer preferably preferably includes includes a lubricant a lubricant in addition in addition to the above to the above

water-dispersible resin water-dispersible resin binder. binder. The lubricant The lubricant is a substance is a substance that can that can reduce thereduce the coefficient coefficient of of friction on the surface of the heat-sealable layer by being mixed in the heat-sealable layer. friction on the surface of the heat-sealable layer by being mixed in the heat-sealable layer.

[0037]

The lubricant is not specifically limited, and waxes, metal soaps, fatty acid esters, and The lubricant is not specifically limited, and waxes, metal soaps, fatty acid esters, and

the like the like can can be be used, used,for forexample. One example. One ofof thelubricants the lubricantsmay maybebeused usedalone, alone,orortwo twoorormore more of of them maybebeused them may usedinincombination. combination.Examples Examples ofwaxes of the the waxes include include natural natural waxeswaxes

including animal including animal or or plant-derived plant-derived waxes waxes(such (suchasasbeeswax beeswax and and carnauba carnauba wax), wax), mineral mineral waxes waxes

(such (such as as microcrystalline microcrystalline wax), wax), and petroleumwax; and petroleum wax;and andsynthetic syntheticwaxes waxes including including polyolefin polyolefin

wax, paraffin wax, paraffin wax, polyester wax, wax, polyester wax,and andthe the like. like. Examples Examplesof of thethe metal metal soaps soaps include include

calcium stearate, sodium stearate, zinc stearate, aluminum stearate, magnesium stearate, fatty calcium stearate, sodium stearate, zinc stearate, aluminum stearate, magnesium stearate, fatty

acid acid sodium soap,potassium sodium soap, potassiumoleate oleatesoap, soap,castor castor oil oil potassium soap, composites potassium soap, compositesthereof, thereof, and and the like. the Among like. Among thethe above above lubricants, lubricants, paraffinwax, paraffin wax, carnauba carnauba wax, wax, andand polyolefin polyolefin wax wax are are preferable since preferable since the the melting melting point point is iscomparatively comparatively low, low, wax components wax components areeasily are easilyformed formedonon

11 --

the surface of the coating layer, and the effect of improving the blocking resistance is the surface of the coating layer, and the effect of improving the blocking resistance is

excellent. That is, the lubricant preferably contains at least one selected from the group excellent. That is, the lubricant preferably contains at least one selected from the group

consisting of consisting of paraffin paraffinwax, wax, carnauba wax, and carnauba wax, andpolyolefin polyolefinwax. wax.FromFrom the the viewpoint viewpoint of of imparting the imparting the slip slip property property and and improving dampproofness, improving dampproofness, thelubricant the lubricantpreferably preferablycontains contains paraffin wax. paraffin wax.

As carnauba As carnaubawax, wax,a asynthesized synthesizedproduct productorora acommercially commercially available available product product maymay be be used. Examples used. Examples of the of the commercially commercially available available product product include include Selosol Selosol 524 524 available available fromfrom

ChukyoYushi Chukyo Yushi Co., Co., Ltd. Ltd.and andMichem Michem Lube Lube 160RPH available from 160RPH available from Michelman. The Michelman. The

paraffin wax paraffin to be wax to be used maybebeany used may anyofofsynthetic syntheticproducts productsand andcommercially commercially available available

products, and products, examplesofofthe and examples thecommercially commercially availableproducts available productsinclude includeHidorin Hidorin L-700 L-700 andand the the

like, available like, availablefrom from Chukyo YushiCo., Chukyo Yushi Co.,Ltd. Ltd.As As polyethylene polyethylene wax,wax, a synthesized a synthesized product product or or aa commercially availableproduct commercially available productmay maybebe used.Examples used. Examples ofcommercially of the the commercially available available

product include product include Aquacer Aquacer531 531available availablefrom from BYK. BYK.

[0038]

Whenthe When thewater-dispersible water-dispersibleresin resinbinder bindercontains containsaa styrene-butadiene styrene-butadienecopolymer, copolymer,the the lubricant preferably lubricant preferably contains contains paraffin paraffinwax. When wax. When thethe water-dispersible water-dispersible resin resin binder binder contains contains

an an olefin-unsaturated olefin-unsaturated carboxylic carboxylic acid acid copolymer (preferablyananethylene-(meth)acrylic copolymer (preferably ethylene-(meth)acrylicacid acid copolymer),the copolymer), the lubricant lubricant preferably preferably contains contains carnauba wax. carnauba wax.

[0039]

When the heat-sealable layer contains a lubricant, the content of the lubricant is When the heat-sealable layer contains a lubricant, the content of the lubricant is

preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, and still preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, and still

morepreferably more preferably11 part part by by mass massoror more, more,and andisis preferably preferably 30 30 parts parts by massor by mass or less, less, more more

preferably 10 parts by mass or less, and still more preferably 5 parts by mass or less, relative preferably 10 parts by mass or less, and still more preferably 5 parts by mass or less, relative

to 100 parts by mass of the water-dispersible resin binder. to 100 parts by mass of the water-dispersible resin binder.

[0040]

When the heat-sealable layer contains a lubricant, the content of the lubricant in the When the heat-sealable layer contains a lubricant, the content of the lubricant in the

heat-sealable layer heat-sealable layer is ispreferably preferably0.1% 0.1% by by mass or more, mass or morepreferably more, more preferably0.3% 0.3%bybymass mass or or

more, and more, andstill still more more preferably preferably 1% bymass 1% by massorormore, more,and andpreferably preferably30% 30% by by mass mass or less, or less,

morepreferably more preferably10% 10%byby mass mass or or less,and less, andstill still more preferably5% more preferably 5%bybymass mass or or less. less.

[0041]

In the present embodiment, the heat-sealable layer contains the water-dispersible resin In the present embodiment, the heat-sealable layer contains the water-dispersible resin

binder, and preferably contains the lubricant in addition to the water-dispersible resin binder. binder, and preferably contains the lubricant in addition to the water-dispersible resin binder.

In addition,the In addition, theheat-sealable heat-sealable layer layer may may contain contain the water-dispersible the water-dispersible resinand, resin binder, binder, if and, if

necessary, a pigment in addition to the lubricant. necessary, a pigment in addition to the lubricant.

[0042]

12 --

(Pigment) (Pigment)

In the In the present present embodiment, theheat-sealable embodiment, the heat-sealable layer layer may containthe may contain the above abovewater- water- dispersible resin binder, and, if necessary, a pigment in addition to the lubricant. dispersible resin binder, and, if necessary, a pigment in addition to the lubricant. The The problem of the heat-sealable layer-coated surface sticking to the back surface of the heat- problem of the heat-sealable layer-coated surface sticking to the back surface of the heat-

sealable sealable paper paper to to cause cause peeling peeling (blocking) (blocking) is issuppressed suppressed when producingthe when producing theheat-sealable heat-sealable paper by paper by containing containing aa pigment, pigment,so so that that the the heat-sealable heat-sealable paper paper having having excellent excellent blocking blocking

resistance is obtained. resistance is obtained.

[0043]

Thepigment The pigmentisisnot not specifically specifically limited, limited,and and examples thereof include examples thereof include various various pigments pigments

conventionally used conventionally usedfor for pigment pigmentcoating coatinglayers. layers. TheThe pigment pigment may may be used be used alonealone bytype by one one type or may or beused may be usedinin combination combinationofoftwo twoorormore more types.As the types. As the pigment, pigment, the heat-sealable the heat-sealable layer layer

preferably contains preferably contains a a pigment havingananaspect pigment having aspectratio ratio of of 20 20 or or more fromthe more from the viewpoint viewpointofofheat heat sealing sealing peel peel strength strength and and blocking blocking resistance. Theaspect resistance. The aspectratio ratio of of the the pigment is more pigment is more

preferably 25 or more, further preferably 30 or more, particularly preferably 60 or more, and preferably 25 or more, further preferably 30 or more, particularly preferably 60 or more, and

is is preferably 10,000 preferably 10,000 or or less, less, more more preferably preferably 1,000 1,000 orfurther or less, less, further preferably preferably 300 in 300 or less, or less, in view of view of the the availability availabilityand andsmoothness of the smoothness of the heat-sealable heat-sealable layer layersurface. Theaspect surface. The aspectratio ratio of the of the pigment meansmajor pigment means majoraxis/minor axis/minor axisand axis and may may be be measured measured by following by the the following method. method.

[0044]

Thepigment The pigmentpreferably preferablycontains containsa alayered layeredinorganic inorganiccompound compound having having an aspect an aspect ratio ratio

of 20 of 20 or or more. The more. The form form of of thethe layered layered inorganic inorganic compound compound is tabular. is tabular. When When the pigment the pigment

is is tabular, tabular, the protrusionofofthethepigment the protrusion pigment fromfrom the surface the surface of the of the heat-sealable heat-sealable layer is layer is

suppressed, and suppressed, and a heat-sealable a heat-sealable layerlayer having having excellent excellent blockingblocking resistance resistance is obtained, is obtained, while while maintaining the heat sealing property. maintaining the heat sealing property.

[0045]

Thepigment The pigmentpreferably preferablyhas hasa alength length(average (averageparticle particle size) size) of 0.1m of 0.1 µm or or more and100 more and 100 m orless. µm or less. When When the the length length is is 0.10.1µmm or or more, more, thethe pigment pigment is easily is easily arranged arranged in in paralleltoto parallel

the paper substrate. Further, when the length is 100 m or less, there is little concern that a the paper substrate. Further, when the length is 100 µm or less, there is little concern that a

part of part of the thepigment pigment protrudes protrudes from the heat-sealable from the heat-sealable layer. Thelength layer. The lengthofofthe thepigment pigmentisis morepreferably more preferably0.3 morormore, 0.3 µm more,further furtherpreferably preferably0.5 morormore, 0.5µm more,particularly particularlypreferably preferably 1.0 m 1.0 or more, µm or more,and andisis more preferably3030µmm morepreferably oror less,further less, further preferably preferably 20 mororless, 20 µm less, particularly preferably 15 m or less. particularly preferably 15 µm or less.

[0046]

Here, thelength Here, the lengthofofthethe pigment pigment when when contained contained in the heat-sealable in the heat-sealable layer is determined, layer is determined,

as as follows. follows. AnAn enlarged enlarged image image of of thethe cross cross sectionofofthe section theheat-sealable heat-sealablelayer layer is is captured captured

with an with an electron electron microscope. microscope. At At thistime, this time,the themagnification magnificationisissuch suchthat that about about20 20toto 30

13 --

pigmentsare pigments are included includedin in the the screen. screen. The The lengthofofeach length eachpigment pigment in in thescreen the screenisismeasured. measured. Then, the Then, the average average of of the the lengths lengths obtained obtained is is calculated calculatedas asthe thelength lengthofof thethe pigment. pigment. The The

length of the pigment may be expressed in terms of particle size. length of the pigment may be expressed in terms of particle size.

[0047]

Thepigment The pigmentpreferably preferablyhas hasa athickness thicknessofof200 200nmnmororless. less. TheThe thickness thickness of of thethe

pigmentisis more pigment morepreferably preferably100 100nmnm oror less,further less, further preferably preferably 80 80 nm nmororless, less, even more even more

preferably 50 nm or less, particularly preferably 30 nm or less. Further, it is preferably 5 nm preferably 50 nm or less, particularly preferably 30 nm or less. Further, it is preferably 5 nm

or more, or morepreferably more, more preferably1010nmnmorormore. more.The The smaller smaller the average the average thickness thickness of the of the pigment, pigment,

the higher the heat sealing peel strength is obtained. Here, the thickness of the pigment the higher the heat sealing peel strength is obtained. Here, the thickness of the pigment

whencontained when containedininthe theheat-sealable heat-sealable layer layer is is determined, determined, as as follows. Anenlarged follows. An enlarged image image of of the cross section of the heat-sealable layer is captured with an electron microscope. At this the cross section of the heat-sealable layer is captured with an electron microscope. At this

time, the time, the magnification magnification is is such such that thatabout about20 20 to to30 30pigments pigments are are included included in in the thescreen. The screen. The

thickness of thickness of each each pigment in the pigment in the screen screen is is measured. Then, measured. Then, thethe average average of of thethethicknesses thicknesses obtained obtained isiscalculated calculatedas as thethe thickness thickness of pigment. of the the pigment.

[0048]

Specific examples Specific examples of the of the pigment pigment include include mica, bentonite, mica, bentonite, kaolin, pyrophyllite, kaolin, pyrophyllite, talc, talc, smectite, vermiculite, smectite, vermiculite, chlorite, chlorite, septe septe chlorite, chlorite, serpentine, serpentine, stilpnomelane, stilpnomelane, montmorillonite, montmorillonite,

heavycalcium heavy calciumcarbonate carbonate(ground (ground calcium calcium carbonate), carbonate), lightcalcium light calcium carbonate carbonate (synthetic (synthetic

calcium carbonate), calcium carbonate), composite compositesynthetic syntheticpigment pigmentofofcalcium calcium carbonate carbonate andand other other hydrophilic hydrophilic

organic compounds, organic compounds, satinsatin white, white, lithopone, lithopone, titanium titanium dioxide, dioxide, silica,sulfate, silica, barium bariumcalcium sulfate, calcium sulfate, sulfate,alumina, alumina, aluminum hydroxide,zinc aluminum hydroxide, zincoxide, oxide,magnesium magnesium carbonate, carbonate, silicate,colloidal silicate, colloidal silica, silica, plastic plastic pigments pigments ofof hollow hollow or solid or solid organic organic pigments, pigments, binder pigments, binder pigments, plastic beads, plastic beads,

microcapsules, microcapsules, andand the the like, like, and and the heat-sealable the heat-sealable layer preferably layer preferably containscontains at least one at least one

selected from selected from the the group group consisting consisting ofabove. of the the above.

[0049]

Specific Specific examples ofmica examples of micainclude includesynthetic syntheticmica mica(such (suchasasswelling swellingsynthetic syntheticmica), mica), white mica (muscovite), silk mica (sericite), phlogopite (phlogopite), black mica (biotite), white mica (muscovite), silk mica (sericite), phlogopite (phlogopite), black mica (biotite),

fluorine phlogopite (artificial mica), red mica, soda mica, vanadium mica, illite, tin mica, fluorine phlogopite (artificial mica), red mica, soda mica, vanadium mica, illite, tin mica,

paragonite, and paragonite, brittle mica. and brittle Further, specific mica. Further, specific examples of bentonite examples of bentonite include include montmorillonite. montmorillonite.

[0050]

Specific examples Specific examples of kaolin of kaolin include include various various kaolinskaolins such as such ascalcined kaolin, kaolin, kaolin, calcined kaolin, structured kaolin,andand structured kaolin, delaminated delaminated kaolin. kaolin.

[0051]

14 --

Among Among them, them, in in particular,the particular, the heat-sealable heat-sealable layer layer preferably preferably contains contains aa pigment pigment

having an having an aspect aspect ratio ratio of of 20 20 or or more, more, more preferably contains more preferably contains one one or or more moreselected selected from from mica, bentonite, kaolin, and talc, and still more preferably contains kaolin from the viewpoint mica, bentonite, kaolin, and talc, and still more preferably contains kaolin from the viewpoint

of heat sealing peel strength, blocking resistance, and economy. of heat sealing peel strength, blocking resistance, and economy.

[0052]

Whenthe When theheat-sealable heat-sealablelayer layercontains containsaa pigment, pigment,the the content content of of the the pigment is pigment is

preferably 11 part preferably part by by mass or more, mass or morepreferably more, more preferably33parts parts by by mass massorormore, more,still still more more

preferably 55 parts preferably parts by by mass or more, mass or and even more, and evenstill still more more preferably preferably 8 8 parts parts by by mass mass or or more more

relative to 100 parts by mass of the water-dispersible resin binder from the viewpoint of relative to 100 parts by mass of the water-dispersible resin binder from the viewpoint of

blocking resistance, whereas the content of the pigment is preferably 200 parts by mass or less, blocking resistance, whereas the content of the pigment is preferably 200 parts by mass or less,

more preferably 100 parts by mass or less, and still more preferably 30 parts by mass or less more preferably 100 parts by mass or less, and still more preferably 30 parts by mass or less

relative to 100 parts by mass of the water-dispersible resin binder, from the viewpoint of the relative to 100 parts by mass of the water-dispersible resin binder, from the viewpoint of the

heat sealing property. heat sealing property.

[0053]

Whenthe When theheat-sealable heat-sealablelayer layercontains containsaa pigment, pigment,the the content content of of the the pigment in the pigment in the heat-sealable layer heat-sealable layer is ispreferably preferably1% 1% by by mass or more, mass or morepreferably more, more preferably3%3% byby mass mass or or more, more,

still stillmore more preferably preferably5% 5% by massor by mass or more, more,and andeven evenstill still more preferably 8% more preferably 8%bybymass massor or more more

from the viewpoint of blocking resistance and recyclability, whereas the content of the from the viewpoint of blocking resistance and recyclability, whereas the content of the

pigmentinin the pigment the heat-sealable heat-sealable layer layer is ispreferably preferably70% 70% by by mass or less, mass or less, more preferably 30% more preferably by 30% by

massor mass or less, less, and and still still more morepreferably preferably20% 20% by by mass or less mass or less from the viewpoint from the of the viewpoint of the heat heat

sealing property. sealing property.

[0054]

(Other components) (Other components)

Theheat-sealable The heat-sealable layer layer may containother may contain othercomponents componentsin in additiontotothe addition thewater- water- dispersible resin dispersible resinbinder, binder,and andthe thelubricant and/or lubricant thethe and/or pigment pigmentifif necessary. necessary. Examples ofthe Examples of the other other components includesilane components include silanecoupling couplingagents; agents;defoaming defoaming agents; agents; viscositymodifiers; viscosity modifiers; leveling agents such as surfactants and alcohols; colorants such as coloring dyes. leveling agents such as surfactants and alcohols; colorants such as coloring dyes.

[0055]

The coating amount (basis weight) of the heat-sealable layer is not specifically limited. The coating amount (basis weight) of the heat-sealable layer is not specifically limited.

However,the However, thecoating coatingamount amount (basisweight) (basis weight) isispreferably g/m2orormore, preferably33g/m² more,more more preferably preferably 5 5 g/m2 or g/m² or more, more, and andstill still more more preferably preferably 8 g/m²2 or 8 g/m or more fromthe more from theviewpoint viewpointofofobtaining obtainingaa sufficient heatsealing sufficient heat sealingproperty property and and fromfrom the viewpoint the viewpoint of obtaining of obtaining a packaging a packaging bag that is bag that is

difficult to tear and can be easily opened at the time of opening, and is preferably 30 g/m2 or difficult to tear and can be easily opened at the time of opening, and is preferably 30 g/m² or

less, less, more preferably more preferably 20 20 or 2less, g/m²g/m or less, and still and still more more preferably preferably 15 g/m² 15 less 2from or g/m or less the from the

viewpoint of economy viewpoint of economy and and recyclability. recyclability.

- 15 --

[0056]

<Physical properties of <Physical properties of heat-sealable heat-sealable paper> paper>

(Tear (Tear index) index)

Thelongitudinal The longitudinal and and transverse transverse geometric geometricmean meanofof thetear the tearindex indexofofthe the heat-sealable heat-sealable 2 or more, and preferably 12 mN.m²/g or paper is paper is 10 10 mNm mN.m²/g/g or more, and preferably 12 mNm2/g more or more fromfrom the viewpoint the viewpoint of of obtaining a packaging bag that is difficult to tear and can be easily opened at the time of obtaining a packaging bag that is difficult to tear and can be easily opened at the time of

opening, and the upper limit thereof is not specifically limited, but is preferably 30 mNm2/g opening, and the upper limit thereof is not specifically limited, but is preferably 30 mN.m²/g

2 or less, and still more preferably 20 mN.m²/g or less, or less,more more preferably preferably 25 25 mNm mN.m²/g/g or less, and still more preferably 20 mNm2/gororless. less. The tear index of the heat-sealable paper is a value obtained by dividing the tear The tear index of the heat-sealable paper is a value obtained by dividing the tear

strength strength measured accordingtotoJIS measured according JISPP8116:2000 8116:2000by by thethe basisweight. basis weight. A method A methodfor foradjusting adjustingthe thelongitudinal longitudinal and and transverse transverse geometric geometricmean meanofof thetear the tear index ofthe index of theheat-sealable heat-sealable paper paper to the to the above above range range is not is not specifically specifically limited,limited, but the but the

longitudinal and longitudinal and transverse transverse geometric meanofofthe geometric mean thetear tear index index can can be be adjusted adjusted by by selecting selecting the the kind of pulp constituting the paper substrate or beating conditions (the beating degree, the kind of pulp constituting the paper substrate or beating conditions (the beating degree, the

pulp concentration at the time of beating, or the like). The tear index can be increased by pulp concentration at the time of beating, or the like). The tear index can be increased by

using, for using, for example, example, softwood pulp,preferably softwood pulp, preferably needle needleunbleached unbleachedkraft kraftpulp. pulp.In In addition,the addition, the tear index can be adjusted by setting an appropriate beating degree, and a high beating degree tear index can be adjusted by setting an appropriate beating degree, and a high beating degree

(a (a low low CSF) tendsto CSF) tends to decrease decrease the the tear tear index. Moreover, index. Moreover, beating beating at at a a highconcentration high concentration results in a branched or microfibrillar pulp, which makes it possible to increase the tearing results in a branched or microfibrillar pulp, which makes it possible to increase the tearing

resistance. Moreover, resistance. Moreover, use use of of extensiblepaper extensible papersubjected subjectedtotoClupak Clupak processing processing as as thethe paper paper

substrate canalso substrate can alsoabsorb absorb energy energy at time at the the time of tearing of tearing when when the the extensible extensible paper is elongated, paper is elongated,

which makes it possible to obtain a high tear index. which makes it possible to obtain a high tear index.

[0057]

The tear index of the heat-sealable paper in a longitudinal direction is preferably 8 The tear index of the heat-sealable paper in a longitudinal direction is preferably 8

mNm2/gorormore, mN.m²/g more,andand more more preferably preferably 10 10 mNmor2/gmore mN.m²/g or more fromviewpoint from the the viewpoint of obtaining of obtaining

aa packaging packaging bagbag thatthat is difficult is difficult to to tear tear andand can can be easily be easily opened opened at the at theoftime time of opening, opening, and and 2 the upper limit thereof, which is not specifically limited, is preferably 30 mNm /g or less, the upper limit thereof, which is not specifically limited, is preferably 30 mN.m²/g or less,

morepreferably more preferably24 mNm2/g 24mN.m²/g or or less,and less, andstill still more preferably 18 more preferably mNm2/g 18mN.m²/g or or less. less.

[0058]

The tear index of the heat-sealable paper in a transverse direction is preferably 10 The tear index of the heat-sealable paper in a transverse direction is preferably 10

mNm2/gorormore, mN.m²/g more,more more preferably preferably 12 12 mNmor2/gmore, mN.m²/g or more, and still and still moremore preferably preferably 14 14 mNm2/gorormore mN.m²/g more from from thethe viewpoint viewpoint of of obtaining obtaining a packaging a packaging bag bag thatthat is is difficulttoto tear difficult tear and and

can be easily opened at the time of opening, and the upper limit thereof, which is not can be easily opened at the time of opening, and the upper limit thereof, which is not

specifically limited, is preferably 32 mN.m²/g or 2less, more preferably 28 mN.m²/g or less, 2 specifically limited, is preferably 32 mNm /g or less, more preferably 28 mNm /g or less, 2 or less. and still more and still more preferably preferably 24 24 mNm mN.m²/g/g or less.

16 --

[0059]

(Burst (Burst index) index)

2 The burst index of the heat-sealable paper is 3.0 kPam /g or more, and preferably 3.5 The burst index of the heat-sealable paper is 3.0 kPa.m²/g or more, and preferably 3.5

kPa-m²/g2 or more, from the viewpoint of obtaining a packaging bag that is difficult to tear and kPam /g or more, from the viewpoint of obtaining a packaging bag that is difficult to tear and can be easily opened at the time of opening, and the upper limit thereof, which is not can be easily opened at the time of opening, and the upper limit thereof, which is not

specifically limited, is preferably 10.0 kPa.m²/g or2 less, more preferably 8.5 kPa.m²/g or less, specifically limited, is preferably 10.0 kPam /g or less, more preferably 8.5 kPam /g or less,2

and still more and still preferably more preferably 7.07.0 kPamor2/g kPa.m²/g or less. less.

The burst index of the heat-sealable paper is a value obtained by dividing the bursting The burst index of the heat-sealable paper is a value obtained by dividing the bursting

strength strength measured accordingtotoJIS measured according JISPP8112:2008 8112:2008by by thethe basisweight. basis weight. A method for adjusting the burst index of the heat-sealable paper to the above range is A method for adjusting the burst index of the heat-sealable paper to the above range is

not specifically limited, but the burst index of the heat-sealable paper can be adjusted by not specifically limited, but the burst index of the heat-sealable paper can be adjusted by

selecting thekind selecting the kindofofpulp pulp constituting constituting the the paper paper substrate substrate or theor the beating beating conditions, conditions, and the and the

burst index burst index can can be be increased increased by using, for by using, for example, softwoodpulp, example, softwood pulp,preferably preferablyneedle needle unbleachedkraft unbleached kraft pulp. pulp. InInaddition, addition,the theburst burst index indexcan canbe beadjusted adjustedby bysetting setting an an appropriate appropriate beating degree, beating degree, and a high and a high beating beating degree (a low degree (a CSF)tends low CSF) tendstoto decrease decreasethe the burst burst index. index. Moreover, beating Moreover, beating at aat a high high concentration concentration resultsresults in a branched in a branched or microfibrillar or microfibrillar pulp, which pulp, which

makes it possible to increase the bursting strength. makes it possible to increase the bursting strength.

Moreover,use Moreover, useofofextensible extensible paper papersubjected subjectedto to Clupak Clupakprocessing processingasasthe thepaper paper substrate canalso substrate can alsoobtain obtain a high a high burst burst index. index. In addition, In addition, additionaddition of an paper of an internal internal paper strengthening agent strengthening agent or the or the likelike to the to the paper paper substrate substrate canincrease can also also increase theindex. the burst burst index.

[0060]

(Heat sealingpeel (Heat sealing peel strength) strength)

In the In the heat-sealable heat-sealablepaper paper of ofthe thepresent presentembodiment, fromthe embodiment, from the viewpoint viewpointofofobtaining obtaining aa packaging packaging bagbag thatthat is difficult is difficult to to tear tear andand can can be easily be easily opened opened at the at theoftime time of opening, opening, the the heat sealing heat sealing peel peel strength strengthisis2.0 N/15 2.0 N/15mm or more, mm or preferably 3.0 more, preferably 3.0 N/15 mm N/15 mm or or more, more, more more

preferably 4.0 preferably 4.0 N/15 mmorormore, N/15 mm more, and and still more still morepreferably preferably4.5 4.5N/15 N/15mmmm or more, or more, and and is is preferably 10.0 preferably 10.0 N/15 mm N/15 mm or or less,more less, morepreferably preferably9.0 9.0N/15 N/15mmmm or less, or less, still more still morepreferably preferably 8.0 N/15mmmm 8.0 N/15 or less, or less, eveneven stillstill moremore preferably preferably 6.5mmN/15 6.5 N/15 mmandorfurther or less, less, and further still more still more

preferably 7.0 preferably 7.0 N/15 mmororless. N/15 mm less. Moreover, Moreover, the the heatheat sealing sealing peel peel strength strength is ispreferably preferably4.8 4.8 N/15mm N/15 mmor or more more from from the the viewpoint viewpoint of automatic of automatic packaging packaging formability. formability. Thestrength The peel peel strength of the heat-sealable layer is a peel strength when two heat-sealable layers are heat-sealed of the heat-sealable layer is a peel strength when two heat-sealable layers are heat-sealed

under the under the conditions conditions of of 150C, 0.2 MPa, 150°C, 0.2 MPa,and and1 1second, second,specifically, specifically, is is aa value value measured by measured by

the method the accordingtotoExamples, method according Examples, which which is is described described below. below.

The peel strength can be adjusted by selecting the glass transition temperature, the kind, The peel strength can be adjusted by selecting the glass transition temperature, the kind,

and the coating and the coating amount ofthe amount of the water-dispersible water-dispersible resin resin binder. Forexample, binder. For example, theresins the resinsmelt melt

17 --

and heat-sealable and heat-sealable layers layers adhere adhere well well to to each each other other under under predetermined heat sealing predetermined heat sealing conditions by setting the glass transition temperature of the water-dispersible resin binder to conditions by setting the glass transition temperature of the water-dispersible resin binder to

100C 100°C oror less,sosothat less, thata adesired desired peel peel strength strength canensured. can be be ensured.

[0061]

(Surface smoothness) (Surface smoothness)

TheOken The Okensmoothness smoothness of of a surface a surface of of theheat-sealable the heat-sealablelayer layerofofthe the heat-sealable heat-sealable paper paper

of the of the present present embodiment embodiment isispreferably preferably 30 30seconds secondsorormore, more,more more preferably preferably 4040 seconds seconds or or more, and more, andstill still more more preferably preferably 50 50 seconds or more, seconds or more, from fromthe theviewpoint viewpointofofimproving improving theheat the heat sealing peelstrength, sealing peel strength,andand thethe upper upper limit limit thereof, thereof, whichwhich is not is not specifically specifically limited,limited, is is preferably 500 seconds or less, more preferably 300 seconds or less, and still more preferably preferably 500 seconds or less, more preferably 300 seconds or less, and still more preferably

100 seconds 100 seconds or or less. less.

Theheat-sealable The heat-sealable layer layer may beprovided may be providedononW W side side (wire (wire side)ofofthe side) thepaper papersubstrate substrate or may be provided on F side (felt side), which is not specifically limited. Here, the W side or may be provided on F side (felt side), which is not specifically limited. Here, the W side

(wire side)isis aa side (wire side) sidethat thatisis in in contact contactwith with a wire a wire when when the paper the paper strip strip is is formed, formed, and its and its

opposite sideisisthe opposite side theF Fside side(felt (feltside). side). Further, the Oken smoothness of the surface opposite to the heat-sealable layer (the Further, the Oken smoothness of the surface opposite to the heat-sealable layer (the

other surface of the paper substrate, for example, in the case where the heat-sealable layer is other surface of the paper substrate, for example, in the case where the heat-sealable layer is

provided only on one surface of the paper substrate, and the paper substrate is exposed on the provided only on one surface of the paper substrate, and the paper substrate is exposed on the

other surface) other surface) is ispreferably preferably3 3seconds secondsor ormore, more, and and more preferably 55 seconds more preferably or more seconds or morefrom from the viewpoint of improving the printability, and the upper limit thereof, which is not the viewpoint of improving the printability, and the upper limit thereof, which is not

specifically limited,isispreferably specifically limited, preferably 1,000 1,000 seconds seconds or less, or less, more preferably more preferably 300orseconds 300 seconds less, or less, and still more and still preferably more preferably 100100 seconds seconds or less. or less.

TheOken The Okensmoothness smoothness is is measured measured in accordance in accordance withwith JIS JIS P8155:2010. P8155:2010.

TheOken The Okensmoothness smoothness of of each each of of thethe surface surface ofof theheat-sealable the heat-sealablelayer layerand andthe theopposite opposite surface surface of of the the heat-sealable heat-sealablepaper paper can can be be adjusted adjusted to tothe theaforementioned aforementioned range range by by super super

calendering or the like, which is described below. calendering or the like, which is described below.

[0062]

(Basis (Basis weight) weight)

From the viewpoint of obtaining a packaging bag that is difficult to tear and can be From the viewpoint of obtaining a packaging bag that is difficult to tear and can be

easily opened at the time of opening, the basis weight of the heat-sealable paper of the present easily opened at the time of opening, the basis weight of the heat-sealable paper of the present

2 more, more preferably 70 g/m² or2 more, still more embodiment embodiment is is preferably5050g/m² preferably g/moror more, more preferably 70 g/m or more, still more preferably 80 preferably g/m2 or 80 g/m² or more, more, and andeven evenstill still more preferably 85 more preferably g/m2or 85 g/m² or more, more,and andisis preferably preferably 2 less, more preferably 150 g/m² or less, 2 still more preferably 120 g/m² or less, and 2 200 g/m or less, more preferably 150 g/m or less, still more preferably 120 g/m or less, and 200 g/m² or

2 even still more preferably 100 g/m or less. even still more preferably 100 g/m² or less.

Thebasis The basis weight weightof of the the heat-sealable heat-sealable paper paper is is measured accordingtoto JIS measured according JIS PP 8124:2011. 8124:2011.

- 18 --

[0063]

(Thickness) (Thickness)

easily opened at the time of opening, the thickness of the heat-sealable paper of the present easily opened at the time of opening, the thickness of the heat-sealable paper of the present

embodiment embodiment is is preferably6060µmm preferably or or more, more, more more preferably preferably 80 µm mmore, 80 or or more, stillstill moremore preferably 90 preferably morormore, 90 µm more,and andeven evenstill still more morepreferably 100µmm preferably100 or or more, more, andand is is preferably preferably

300 mororless, 300 µm less, more morepreferably 200µmm preferably200 or or less,and less, andstill still more preferably 150 more preferably mororless. 150 µm less. Thethickness The thickness of of the the heat-sealable heat-sealable paper paper is ismeasured accordingto measured according to JIS JIS PP 8118:2014. 8118:2014.

[0064]

(Density) (Density)

easily opened at the time of opening, the density of the heat-sealable paper is preferably 0.50 easily opened at the time of opening, the density of the heat-sealable paper is preferably 0.50

g/cm3 or g/cm³ or more, more,more morepreferably preferably0.60 0.60g/cm³ 3 more, and still more preferably 0.65 g/cm³ or g/cmoror more, and still more preferably 0.65 g/cm3 or 3 more preferably 0.90 g/cm³ or less, 3and still more more, and is preferably 1.0 g/cm or less, more preferably 0.90 g/cm or less, and still more more, and is preferably 1.0 g/cm³ or less,

preferably 0.80 preferably g/cm³3 or 0.80 g/cm or less. less. The Thedensity densityofofthe theheat-sealable heat-sealable paper paperis is calculated calculated from the from the

basis weight and the thickness of the heat-sealable paper that are obtained from the above basis weight and the thickness of the heat-sealable paper that are obtained from the above

measurement methods. measurement methods.

[0065]

(Clark stiffness) (Clark stiffness)

The longitudinal and transverse geometric mean of the Clark stiffness of the heat- The longitudinal and transverse geometric mean of the Clark stiffness of the heat-

sealable paperisispreferably sealable paper preferably 20 more, 20 or or more, more more preferably preferably 30 or 30 or more, more, still morestill more preferably preferably 35 35 or more, or and even more, and evenstill still more more preferably preferably 40 40 or or more fromthe more from the viewpoint viewpointofofobtaining obtainingaa packaging bag that is difficult to tear and can be easily opened at the time of opening, and the packaging bag that is difficult to tear and can be easily opened at the time of opening, and the

longitudinal and transverse geometric mean of the Clark stiffness of the heat-sealable paper is longitudinal and transverse geometric mean of the Clark stiffness of the heat-sealable paper is

preferably 150 or less, more preferably 100 or less, still more preferably 85 or less, even still preferably 150 or less, more preferably 100 or less, still more preferably 85 or less, even still

more preferably 70 or less, or may be 60 or less, or may be 50 or less from the viewpoint of more preferably 70 or less, or may be 60 or less, or may be 50 or less from the viewpoint of

automatic packagingformability. automatic packaging formability. The longitudinal and transverse geometric mean of the Clark stiffness of the heat- The longitudinal and transverse geometric mean of the Clark stiffness of the heat-

sealable sealable paper paper is is obtained obtained by by determining determining aa geometric meanofofClark geometric mean Clarkstiffnesses stiffnesses in in the the longitudinal direction longitudinal direction and and in in the thetransverse transversedirection directionmeasured measured by by the themethod of Example method of Example

according to JIS according to JIS PP 8143:2009. 8143:2009.

A method A methodfor foradjusting adjustingthe thelongitudinal longitudinal and and transverse transverse geometric geometricmean meanofof theClark the Clark stiffness of the stiffness of the heat-sealable heat-sealable paper paper is not is not specifically specifically limited limited butlongitudinal but the the longitudinal and and transverse geometric mean of the Clark stiffness of the heat-sealable paper can be adjusted by transverse geometric mean of the Clark stiffness of the heat-sealable paper can be adjusted by

conditions such as the kind or the beating degree of pulp constituting the paper substrate, the conditions such as the kind or the beating degree of pulp constituting the paper substrate, the

- 19 --

basis weight, basis weight, calendering, calendering, and and Clupak processing.ForFor Clupak processing. example, example, whenwhen softwood softwood pulp pulp and and hardwood pulp are used as the pulp constituting the paper substrate, an increase in the content hardwood pulp are used as the pulp constituting the paper substrate, an increase in the content

of the of the hardwood pulptends hardwood pulp tendstotodecrease decreasethe the Clark Clarkstiffness. stiffness. InInaddition, addition, when whenthe thepulp pulp constituting the constituting the paper paper substrate substratehaving having an an increased increased beating beating degree degree and and a a low low CSF is used, CSF is used, the the Clark stiffness Clark stiffness tends tendsto todecrease. Moreover,a adecrease decrease. Moreover, decreaseininthe thebasis basis weight weighttends tendsto to decrease decrease the Clark stiffness, and the paper substrate subjected to Clupak processing or calendaring the Clark stiffness, and the paper substrate subjected to Clupak processing or calendaring

tends to decrease the Clark stiffness. tends to decrease the Clark stiffness.

[0066]

The Clark stiffness of the heat-sealable paper in the longitudinal direction is preferably The Clark stiffness of the heat-sealable paper in the longitudinal direction is preferably

20 or 20 or more, morepreferably more, more preferably3030orormore, more,and andstill still more preferably 40 more preferably 40 or or more morefrom fromthe the viewpoint viewpoint of of obtaining obtaining a packaging a packaging bagisthat bag that is difficult difficult to teartoand tear canand can beopened be easily easilyatopened the at the time of opening, and is preferably 250 or less, more preferably 200 or less, still more time of opening, and is preferably 250 or less, more preferably 200 or less, still more

preferably 150 or less, even still more preferably 100 or less, further still more preferably 85 preferably 150 or less, even still more preferably 100 or less, further still more preferably 85

or less, much more preferably 80 or less, particularly preferably 75 or less, may be 70 or less, or less, much more preferably 80 or less, particularly preferably 75 or less, may be 70 or less,

maybebe6565ororless, may less, and and may be5555ororless may be less from fromthe the viewpoint viewpointofofautomatic automaticpackaging packaging formability. formability.

[0067]

The Clark stiffness of the heat-sealable paper in the transverse direction is preferably The Clark stiffness of the heat-sealable paper in the transverse direction is preferably

20 or 20 or more, morepreferably more, more preferably3030orormore, more,and andstill still more preferably 35 more preferably 35 or or more morefrom fromthe the viewpoint viewpoint of of obtaining obtaining a packaging a packaging bagisthat bag that is difficult difficult to teartoand tear canand can beopened be easily easilyatopened the at the time of opening, and is preferably 250 or less, more preferably 200 or less, still more time of opening, and is preferably 250 or less, more preferably 200 or less, still more

or less, much more preferably 80 or less, particularly preferably 70 or less, may be 60 or less, or less, much more preferably 80 or less, particularly preferably 70 or less, may be 60 or less,

and maybebe5050ororless and may less from fromthe the viewpoint viewpointofofautomatic automaticpackaging packaging formability. formability.

[0068]

(Clark stiffness/basisweight) (Clark stiffness/basis weight) 2 A value (Clark stiffness/basis weight) (unit: m /g) obtained by dividing the A value (Clark stiffness/basis weight) (unit: m²/g) obtained by dividing the

longitudinal and transverse geometric mean of the Clark stiffness of the heat-sealable paper longitudinal and transverse geometric mean of the Clark stiffness of the heat-sealable paper

2 the heat-sealable paper is preferably 0.20 m²/g or more, 2 more by the basis weight (g/m ) of the heat-sealable paper is preferably 0.20 m /g or more, more by the basis weight (g/m²) of

2 or more, and still more preferably 0.40 m²/g preferably 0.30 preferably 0.30 m /g or more, and still more preferably 0.40 m2/g or m²/g or more fromthe more from theviewpoint viewpoint of obtaining a packaging bag that is difficult to tear and can be easily opened at the time of of obtaining a packaging bag that is difficult to tear and can be easily opened at the time of

opening and opening and from from the the viewpoint viewpoint of formability of formability (e.g., appearance (e.g., appearance of a bag), of anda is bag), and is preferably preferably

1.20 m2/gororless, 1.20 m²/g less,more more preferably preferably 1.00 1.00 m2less, m²/g or /g or even less,still evenmore stillpreferably more preferably 0.90 m²/g 0.90 or m2/g or less, much more preferably 0.80 m²/g or 2less, particularly preferably 0.65 m²/g or less, 2 may be less, much more preferably 0.80 m /g or less, particularly preferably 0.65 m /g or less, may be

20 --

0.60 m2/g or 0.60 m²/g or less, less, and and may be 0.55 may be m2/gor 0.55 m²/g or less less from the viewpoint from the of automatic viewpoint of automaticpackaging packaging formability. formability.

In addition, In addition, when "the longitudinal when "the longitudinal and and transverse transverse geometric meanofofClark geometric mean Clark stiffness/basis weight stiffness/basis weight (unit: m2/g)" (unit:m²/g)" is 1.00 is 1.00 m²/gm 2 less, the heat-sealable paper has an or/g or less, the heat-sealable paper has an appropriate appropriate softness softness and and the the heat-sealable heat-sealable paper paper can can follow follow deformation whenformed deformation when formed with with a a

bag making bag makingmachine. machine. Therefore, Therefore, it thought it is is thought that that wrinkles wrinkles or or bad bad appearance appearance is prevented, is prevented,

and excellent automatic and excellent packagingformability automatic packaging formabilityisis achieved. achieved. Moreover, Moreover, whenwhen "the "the

longitudinal and transverse geometric mean of Clark stiffness/basis weight (unit: m2/g)" is longitudinal and transverse geometric mean of Clark stiffness/basis weight (unit: m²/g)" is

2 or more, it is thought that firmness or robustness of the packaging bag is improved, 0.20 m /g or more, it is thought that firmness or robustness of the packaging bag is improved, 0.20 m²/g

and the packaging and the bagisis prevented packaging bag preventedfrom frombeing beingtorn. torn. In the specification, the phrase "excellent automatic packaging formability" means that In the specification, the phrase "excellent automatic packaging formability" means that

aa bag bag can be continuously can be continuouslyproduced producedwith withananautomatic automatic packaging packaging machine, machine, and and thatthat the the

appearance of the appearance of the obtained obtained bag bagis is good. Here, good. Here, thethe phrase phrase "a"a bag bag can can be be continuously continuously

produced"means produced" means thatwhen that when a packaging a packaging bagbag is formed is formed withwith an automatic an automatic packaging packaging machine, machine,

phenomena phenomena such such as as wrinkles, wrinkles, meandering, meandering, fracture fracture of of a packaging a packaging material, material, andand sticking sticking toto a a packagingmachine packaging machinedodo not not occur,ororthat occur, thateven evensuch suchphenomena phenomena occur, occur, it does it does notnot affect affect

continuousproduction continuous productionofofbags. bags.Furthermore, Furthermore, the the phrase phrase "the "the appearance appearance of aofbag a bag is good" is good"

meansthat means that bad badappearance appearancesuch suchasaswrinkles wrinklesonona abag, bag,seal sealdefect defect(misalignment (misalignmentofofa asealed sealed portion), or deformation is not found, or that even such bad appearance is found, it falls portion), or deformation is not found, or that even such bad appearance is found, it falls

within an within an acceptable acceptable range. range.

[0069]

[0069] 2 A value (Clark stiffness/basis weight) (unit: m /g) obtained by dividing the Clark A value (Clark stiffness/basis weight) (unit: m²/g) obtained by dividing the Clark

stiffness of the stiffness of the heat-sealable heat-sealable paper paper in the in the longitudinal longitudinal direction direction with with the theweight basis weight (g/m2) basis (g/m²) 2 2 of the of the heat-sealable heat-sealablepaper paper is ispreferably preferably0.20 0.20mm²/g /g orormore, more,more more preferably preferably 0.30 0.30 m m²/g/g or or more, more,

2 and still more and still more preferably preferably 0.40 0.40 m m²/g/g or or more fromthe more from the viewpoint viewpointofofobtaining obtainingaa packaging packagingbag bag that is difficult to tear and can be easily opened at the time of opening, and is preferably 2.40 that is difficult to tear and can be easily opened at the time of opening, and is preferably 2.40

2 or less, more preferably 2.00 m²/g or2 less, still more preferably 1.50 m²/g or less, 2 even m /g or less, more preferably 2.00 m /g or less, still more preferably 1.50 m /g or less, even m²/g

still stillmore preferably1.00 more preferably 1.00 m2or/gless, m²/g or less, further further still still moremore preferably preferably 2 0.90ormless, 0.90 m²/g /g oryetless, evenyet even

2 2 or less, may be 0.60 still more still more preferably preferably0.80 0.80m /g or m²/g or less, less,much much more preferably 0.70 more preferably 0.70 m /g or less, may be 0.60 m²/g

m2/g or m²/g or less, less, orormay may be be 0.55 0.55 m 2 or less from the viewpoint of automatic packaging /g or less from the viewpoint of automatic packaging m²/g

formability. formability.

[0070]

[0070] 2 A value (Clark stiffness/basis weight) (unit: m /g) obtained by dividing the Clark A value (Clark stiffness/basis weight) (unit: m²/g) obtained by dividing the Clark

stiffness of the stiffness of the heat-sealable heat-sealable paper paper in the in the transverse transverse direction direction with with the the weight basis (g/m²) of(g/m2) of basis weight 2 2 or more, the heat-sealable the heat-sealable paper paper is ispreferably preferably0.20 0.20mm²/g /g orormore, more, more more preferably preferably 0.30 0.30 m /g or more, m²/g

- 21 --

2 and still and still more more preferably preferably 0.40 0.40 m m²/g/g or or more fromthe more from the viewpoint viewpointofofobtaining obtainingaa packaging packagingbag bag that is difficult to tear and can be easily opened at the time of opening, and is preferably 1.20 that is difficult to tear and can be easily opened at the time of opening, and is preferably 1.20

2 or less, more preferably 1.00 m²/g or2 less, still more preferably 0.90 m²/g or less, 2 m /g or less, more preferably 1.00 m /g or less, still more preferably 0.90 m /g or less, m²/g

2 less, and may be 0.60 m²/g or less 2 from the viewpoint of particularly preferably 0.80 m /g or less, and may be 0.60 m /g or less from the viewpoint of particularly preferably 0.80 m²/g or

automatic packagingformability. automatic packaging formability.

[0071]

(Piercing strength) (Piercing strength)

Thepiercing The piercing strength strength of of the the heat-sealable heat-sealable paper paper is ispreferably preferably10.0 10.0NNor ormore, more,more more

preferably 11.0 preferably 11.0 N or more, N or more, still still more more preferably preferably 12.0 12.0 N N or or more, and even more, and evenstill still more more

preferably 12.5 N or more from the viewpoint of obtaining a packaging bag that is difficult to preferably 12.5 N or more from the viewpoint of obtaining a packaging bag that is difficult to

tear, and the upper limit thereof, which is not specifically limited, is preferably 30.0 N or less, tear, and the upper limit thereof, which is not specifically limited, is preferably 30.0 N or less,

more preferably 25.0 N or less, still more preferably 20.0 N or less, even still more preferably more preferably 25.0 N or less, still more preferably 20.0 N or less, even still more preferably

18.0 18.0 N or less, N or less,and and much morepreferably much more preferably17.0 17.0NNororless less from fromthe theviewpoint viewpointofofobtaining obtainingheat- heat- sealable paperhaving sealable paper having a desirable a desirable ClarkClark stiffness stiffness andthefrom and from the viewpoint viewpoint of easy production. of easy production.

Thepiercing The piercing strength strength of of the the heat-sealable heat-sealable paper paper is ismeasured measured according to JIS according to JIS Z Z

1717:2019. 1717:2019.

A method for adjusting the piercing strength of the heat-sealable paper to the above A method for adjusting the piercing strength of the heat-sealable paper to the above

range is not specifically limited but the piercing strength of the heat-sealable paper can be range is not specifically limited but the piercing strength of the heat-sealable paper can be

adjusted by selecting conditions such as the kind or beating degree of pulp constituting the adjusted by selecting conditions such as the kind or beating degree of pulp constituting the

paper substrate, paper substrate, basis basisweight, weight,and and Clupak processing. ForFor Clupak processing. example, example, when when at least at least oneone

selected selected from softwoodpulp from softwood pulpand andhardwood hardwood pulp pulp as the as the pulp pulp constituting constituting thepaper the papersubstrate substrateisis used, an increase in the content of softwood pulp tends to increase piercing strength. used, an increase in the content of softwood pulp tends to increase piercing strength. In In addition, when addition, the pulp when the pulp constituting constituting the the paper paper substrate substratehaving having an an increased increased beating beating degree degree

and and aa low CSFisisused, low CSF used, the the piercing piercing strength strength tends tends to to decrease. Moreover, decrease. Moreover, anan increaseininthe increase the basis weight basis tends to weight tends to increase increase piercing piercing strength. Moreover,the strength. Moreover, thepaper papersubstrate substratesubjected subjectedtoto Clupakprocessing Clupak processingincreases increaseselongation elongationofofpaper paperand andcan canabsorb absorbananimpact impact due due to to piercing, piercing,

which tends to increase piercing strength. which tends to increase piercing strength.

[0072]

[Production methodofofheat-sealable

[Production method heat-sealablepaper] paper] Theproduction The productionmethod methodof of theheat-sealable the heat-sealablepaper paperofofthe theembodiment embodimentis is notnot

specifically specifically limited. Examplesthereof limited. Examples thereofinclude includea aproduction productionmethod method comprising comprising an an

application step of applying at least one heat-sealable layer on at least one surface of a paper application step of applying at least one heat-sealable layer on at least one surface of a paper

substrate substrate obtained obtained by by a a method that comprises method that comprisesaacooking cookingstep stepofofcooking cookinga araw rawmaterial materialpulp, pulp, aa beating beating step step of ofbeating beatingaadispersion dispersioncontaining containing20 20mass% or more mass% or moreand and4545mass% mass% or less or less of of

the raw the material pulp raw material pulp subjected to cooking, subjected to cooking, and a papermaking and a stepofofmaking papermaking step making paper paper from from thethe

22 --

raw material raw material pulp pulp subjected subjected to to beating. Each beating. Each stepofofthe step theproduction productionmethod method will will be be

described below. described below.

[0073]

(Cooking step) (Cooking step)

Thecooking The cookingstep stepisis step step of of cooking cooking aa raw material pulp. raw material pulp. The The kappa kappa number number of of the the raw material raw material pulp pulp is is preferably preferably 30 30 or or more and 60 more and 60 or or less less by by the the cooking cooking step. Although step. Although notnot

specifically limited, raw material chips used as a material of the raw material pulp are specifically limited, raw material chips used as a material of the raw material pulp are

preferably treated preferably treated with with aa chemical chemical solution solution containing containing sodium hydroxide.As As sodium hydroxide. the the method method for for treatment with treatment with aa chemical solution containing chemical solution containing sodium sodiumhydroxide, hydroxide,a aknown known treatment treatment method method

using aa known using chemicalsolution known chemical solutioncan canbebeused. used.

[0074]

By setting the kappa number of the raw material pulp 30 or more and 60 or less, it is By setting the kappa number of the raw material pulp 30 or more and 60 or less, it is

possible to obtain heat-sealable paper that can form a packaging bag, which is difficult to tear possible to obtain heat-sealable paper that can form a packaging bag, which is difficult to tear

and can be and can be easily easily opened at the opened at the time time of of opening. opening. From From this this pointofofview, point view,the thekappa kappanumber number of raw material pulp is preferably 50 or less, more preferably 45 or less. of raw material pulp is preferably 50 or less, more preferably 45 or less.

[0075]

Theraw The rawmaterial materialchips chipsused usedasas aa material material of of the the raw raw material material pulp pulp preferably preferably contains contains

softwood pulpasasaa main softwood pulp maincomponent. component. The "raw The "raw material material chipschips containing containing softwood softwood pulp pulp as a as a

maincomponent" main component"hashas a content a content of of thesoftwood the softwoodof of over over 50 50 mass%, mass%, preferably preferably a content a content of the of the

softwood of80 softwood of 80mass% mass%or or more, more, more more preferably preferably 90 mass% 90 mass% or more, or more, further further preferably preferably 100 100

mass%,ininthe mass%, theraw rawmaterial materialchips. chips.

[0076]

Theraw The rawmaterial materialpulp pulpmay maynot notbebebleached bleached oror may may be be bleached. bleached. Thematerial The raw raw material pulp is pulp is preferably preferably one one or or more selected from more selected the group from the consisting of group consisting of bleached kraft pulp bleached kraft pulp and and

unbleachedkraft unbleached kraft pulp, pulp, more morepreferably preferablyunbleached unbleachedkraft kraftpulp. pulp.

[0077]

(Beating step) (Beating step)

Thebeating The beating step step is is aa step stepof ofbeating beatinga adispersion dispersionpreferably containing preferably containing2020mass% or mass% or

moreand more and4545mass% mass%or or less less ofof theraw the rawmaterial materialpulp pulpsubjected subjectedtotocooking. cooking.The The beating beating

method is not specifically limited and preferably includes: dispersing, in water, the raw method is not specifically limited and preferably includes: dispersing, in water, the raw

material pulp material pulp subjected subjected to to cooking, cooking, producing producing aa dispersion dispersion having havingthe the above aboveraw rawmaterial material pulp concentration, pulp concentration, and subjecting the and subjecting the dispersion dispersion to to beating. Thebeating beating. The beatingmethod methodis is not not

specifically limitedandand specifically limited cancan be performed, be performed, for example, for example, using asuch using a beater beater as a such doubleas a double disk disk

refiner, a single disk refiner, and a conical refiner. refiner, a single disk refiner, and a conical refiner.

[0078]

- 23 --

Beating the Beating the dispersion dispersion containing 20 mass% containing 20 mass% oror more more andand 45 45 mass% mass% or less or less of the of the rawraw

material pulp material pulp subjected subjected to to cooking allows aa paper cooking allows paper substrate substrate with with impact resistance and impact resistance and

workability and heat-sealable paper using the paper substrate to be obtained, as well as workability and heat-sealable paper using the paper substrate to be obtained, as well as

allowing excellent allowing excellent productivity. productivity.

[0079]

(Papermaking step) (Papermaking step)

Thepapermaking The papermaking step step isisa astep stepof of making makingpaper paperfrom from theraw the raw material material pulp pulp subjected subjected

to beating. to Thepapermaking beating. The papermaking method method is not is not specifically specifically limited, limited, andand examples examples thereof thereof

include the include the acidic acidic papermaking method papermaking method in in which which papermaking papermaking is performed is performed at a at pHa of pHaround of around 4.5, the 4.5, the neutral neutralpapermaking methodininwhich papermaking method whichpapermaking papermaking is performed is performed at aatpHa pH of about of about 6 to6 to about 9, and about 9, and the the like. In the like. In the papermaking step,agents papermaking step, agentsfor for papermaking papermaking stepsuch step suchasaspHpH adjusters, defoamers, adjusters, defoamers, pitch pitch control control agents, agents, and slime and slime controlcontrol agents agents can can be appropriately be appropriately

added, as added, as required. The required. The paper paper making making machine machine is also is also not not specifically specifically limited,and limited, andexamples examples thereof include thereof include Fourdrinier, Fourdrinier, cylindrical, cylindrical,and andinclined continuous inclined continuouspaper papermachines or multilayer machines or multilayer

paper machines paper machinesthat thatcombine combine these. these.

[0080]

Thepaper The papersubstrate substrate used used for for the the heat-sealable heat-sealable paper paper of of the theembodiment canbebe embodiment can

obtained by obtained by aa method methodincluding includingthe thecooking cookingstep, step,the thebeating beatingstep, step, and the papermaking and the step. papermaking step.

After the After the papermaking step, aa Clupak papermaking step, Clupakstep stepofof shrinking shrinking the the paper paper strip strip using using Clupak Clupak

equipmentmay equipment maybe be provided, provided, as as required.A known required. A known ClupakClupak equipment equipment can beThe can be used. used. The production method production methodofofthe thepaper papersubstrate substrateused usedfor for the the heat-sealable heat-sealable paper paper of of the the embodiment embodiment

is not is not limited limitedtotothe aforementioned the aforementioned method. method.

[0081]

Further, the Further, the production production method ofthe method of the heat-sealable heat-sealable paper paper in in the the embodiment may embodiment may

include a surface treatment step of treating the surface of the paper substrate with an agent. include a surface treatment step of treating the surface of the paper substrate with an agent.

Examplesofofthe Examples theagent agentused usedfor forthe the surface surface treatment treatment step step include include sizing sizing agents, agents, waterproofing waterproofing

agents, agents, water water retention retention agents, agents,thickeners, thickeners,lubricants, andandthethe lubricants, like. like.AAknown device can known device can be be used for the surface treatment step. used for the surface treatment step.

[0082]

Theproduction The productionmethod methodof of theheat-sealable the heat-sealablepaper paperofofthe theembodiment embodiment comprises comprises an an application stepofofapplying application step applying the the heat-sealable heat-sealable layer layer on at on at one least leastsurface one surface of the paper of the paper

substrate substrate obtained obtained as as described described above. The above. The heat-sealable heat-sealable layercoating layer coatingliquid liquid(heat-sealable (heat-sealable layer coating layer coating material) material) may be applied may be applied twice twice or or more. more.

[0083]

24 --

In the case of forming multiple heat-sealable layers on the paper substrate, the In the case of forming multiple heat-sealable layers on the paper substrate, the

aforementioned method aforementioned method of of sequentiallyforming sequentially forming thethe heat-sealablelayers heat-sealable layersisispreferable, preferable, but but there is there isno no limitation limitationtoto this, andand this, a simultaneous multilayer a simultaneous coating multilayer method coating methodmay may be be employed. employed.

Thesimultaneous The simultaneousmultilayer multilayercoating coatingmethod methodis is a amethod methodof of discharging discharging multiple multiple types types of of

coating liquids separately from slit-shaped nozzles to form a liquid laminate and applying the coating liquids separately from slit-shaped nozzles to form a liquid laminate and applying the

laminate to the paper substrate to form multiple heat-sealable layers simultaneously. laminate to the paper substrate to form multiple heat-sealable layers simultaneously.

[0084]

The application equipment for applying the heat-sealable layer coating liquid to the The application equipment for applying the heat-sealable layer coating liquid to the

paper substrate paper substrate is isnot notspecifically specificallylimited, andand limited, known knownequipment maybebeused. equipment may used.Examples Examples of of the application equipment include blade coaters, bar coaters, air knife coaters, slit die coaters, the application equipment include blade coaters, bar coaters, air knife coaters, slit die coaters,

gravure coaters, micro gravure coaters, roll coaters, size presses, gate roll coaters, Sym-sizers, gravure coaters, micro gravure coaters, roll coaters, size presses, gate roll coaters, Sym-sizers,

and thelike. and the like.

[0085]

The drying equipment for drying the heat-sealable layer is not specifically limited, and The drying equipment for drying the heat-sealable layer is not specifically limited, and

knownequipment known equipmentcancan be be used. used. Examples Examples of theof the drying drying equipment equipment includeinclude hot airhot air dryers, dryers,

infrared dryers, gas burners, hot plates, and the like. Further, the drying temperature may be infrared dryers, gas burners, hot plates, and the like. Further, the drying temperature may be

appropriately set in consideration of the drying time. appropriately set in consideration of the drying time.

[0086]

The solvent for the heat-sealable layer coating liquid is not specifically limited, and The solvent for the heat-sealable layer coating liquid is not specifically limited, and

water or an organic solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone, and water or an organic solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone, and

toluene can toluene be used. can be used. Among Among these, these, water water is preferable is preferable as as a dispersionmedium a dispersion medium for for the the heat- heat-

sealable layercoating sealable layer coating liquid, liquid, since since there there is problem is no no problem of volatile of volatile organicorganic solvents. solvents. That is, That is, the heat-sealable layer coating liquid is preferably an aqueous composition for heat-sealable the heat-sealable layer coating liquid is preferably an aqueous composition for heat-sealable

layers. layers.

[0087]

The solid content (solid content concentration) of the heat-sealable layer coating liquid The solid content (solid content concentration) of the heat-sealable layer coating liquid

is not specifically limited and may be appropriately selected from the viewpoint of the coating is not specifically limited and may be appropriately selected from the viewpoint of the coating

property and property and ease ease of of drying drying but but is is preferably preferably 10% by mass 10% by massorormore, more,more more preferably20%20% preferably by by massor mass or more, more,and andstill still more preferably 30% more preferably 30% bybymass massoror more, more, and and is is preferably80% preferably 80%by by mass mass

or less, or less,more more preferably preferably 60% bymass 60% by massororless, less, still still more more preferably preferably50% by mass 50% by massororless, less, and and

even still even still more more preferably preferably 40% bymass 40% by massororless. less.

[0088]

The preferable range of the coating amount (after drying) of the heat-sealable layer is The preferable range of the coating amount (after drying) of the heat-sealable layer is

as as described described above. The above. The heat-sealable heat-sealable layermaymay layer be be oneone layer layer or or maymay be two be two or more or more layers. layers.

- 25 --

Whenthe When thenumber numberof of thethe heat-sealablelayer heat-sealable layerisistwo twoorormore, more,the theaforementioned aforementioned coating coating

amount is the amount is the total total coating coating amount. amount.

[0089]

After the heat-sealable layer is applied and dried, super calendering is preferably After the heat-sealable layer is applied and dried, super calendering is preferably

performed.Here, performed. Here, thethe super super calendering calendering is is provided provided independently independently fromfrom the the papermaking papermaking

and is generally and is generallytotopass pass thethe paper paper to processed to be be processed between between metal metal rolls rolls ora between or between metal rolla metal roll

and anelastic and an elasticroll, roll,heat heatit, it, apply applya apressure pressure thereto, thereto, andand the the like. like. Super Super calendering calendering may be may be performed in one stage or in multiple stages, and there is no specific limitation. performed in one stage or in multiple stages, and there is no specific limitation.

Preferably, super Preferably, super calendering improvesthe calendering improves thesmoothness smoothnessofof thesurface the surfaceofofthe the heat- heat- sealable layer, which results in improvement of the heat sealing peel strength (decrease in the sealable layer, which results in improvement of the heat sealing peel strength (decrease in the

minimum minimum substrate substrate destructiontemperature) destruction temperature) and and a decrease a decrease in in theClark the Clarkstiffness. stiffness. Further, it is preferable since the smoothness of the surface opposite to the heat- Further, it is preferable since the smoothness of the surface opposite to the heat-

sealable layer (the other surface of the paper substrate, for example, in the case where the sealable layer (the other surface of the paper substrate, for example, in the case where the

heat-sealable layer is provided only on one surface of the paper substrate, and the paper heat-sealable layer is provided only on one surface of the paper substrate, and the paper

substrate is exposed substrate is exposed on on the the other other surface) surface) is improved, is improved, as a result as a result ofthe of which which the printability printability is is improved. improved.

Further, since the density of the heat-sealable paper tends to increase by super Further, since the density of the heat-sealable paper tends to increase by super

calendering, and calendering, the surface and the surface smoothness is improved, smoothness is improved,asasdescribed describedabove, above,super supercalendering calenderingisis preferable because preferable delivering the because delivering the heat-sealable heat-sealable paper paper in in the thepacking packing machine duringbag machine during bag makingbecomes making becomes good, good, thereby thereby improving improving processability. processability.

Thelinear The linear pressure pressure in in super super calendering calendering is ispreferably preferably10 10 kg/cm kg/cm or or more, more more, more

preferably 30 preferably kg/cmorormore, 30 kg/cm more,further further preferably preferably 50 50 kg/cm kg/cmorormore, more,and andisispreferably preferably1000 1000 kg/cm or less, more preferably 500 kg/cm or less, further preferably 200 kg/cm or less. kg/cm or less, more preferably 500 kg/cm or less, further preferably 200 kg/cm or less.

However,the However, thelinear linear pressure pressure may maybebeappropriately appropriatelychanged changed according according to to thethe desired desired

smoothnessand smoothness anddensity. density. Further, in the case where heating is performed in super calendering, the heating Further, in the case where heating is performed in super calendering, the heating

temperatureis temperature is not not specifically specificallylimited limitedbut butisis preferably 20C preferably 20°Coror more, more,more more preferably preferably 30C 30°C

or more, or further preferably more, further preferably 35C or more, 35°C or and is more, and is preferably preferably 80C or less, 80°C or less, more more preferably preferably

70C 70°C oror less,further less, furtherpreferably preferably 60°C60C or less, or less, for preventing for preventing deterioration deterioration of the paper of the paper

substrate andthetheheat-sealable substrate and heat-sealable layer layer due due to heat to heat and sticking and sticking of the of the heat-sealable heat-sealable layer while layer while

enhancing the effect of treatment. enhancing the effect of treatment.

[0090]

Theheat-sealable The heat-sealable paper paper according accordingtoto the the present present embodiment can embodiment can be be favorably favorably used used as as aa packaging bagfor packaging bag for foods, foods, household householdgoods, goods,books, books,commodities commodities (soaps, (soaps, cleaning cleaning agents, agents, andand

- 26 --

diapers), and diapers), and the the like. Accordingly,the like. Accordingly, the present present invention invention also also provides provides aa packaging packagingbag bag using the heat-sealable paper. using the heat-sealable paper.

Examples Examples

[0091]

Hereinafter, examples will be mentioned in order to specifically describe this invention, Hereinafter, examples will be mentioned in order to specifically describe this invention,

but this but this invention invention is isnot notlimited toto limited these examples. these examples. Unless otherwisespecified, Unless otherwise specified, the the following following

operations were performed operations were performedunder underthetheconditions conditionsofof23°C 23C and and a relativehumidity a relative humidityofof50%RH. 50%RH. In In the the following following examples andcomparative examples and comparative examples, examples, "parts" "parts" andand "%""%" respectively respectively refer refer to to

"parts "parts by by mass" and "mass%", mass" and "mass%",unless unlessotherwise otherwise specified. specified.

[0092]

[Example

[Example 1]1]

<Preparation of heat-sealable <Preparation of heat-sealable layer layer coating coating material> material>

98 parts 98 parts of of an an aqueous dispersion of aqueous dispersion of aa styrene/butadiene styrene/butadiene copolymer (Nipollatex copolymer (Nipol latex LX407S12, LX407S12, available available from from Zeon Zeon Corporation, Corporation, solid solid content content 46%, 46%, glass glass transition transition temperature: temperature:

18C (catalog 18°C (catalog value)) value)) (in (in terms terms of solid of solid content) content) and 2 and parts2 of parts of a paraffin a paraffin wax emulsion wax emulsion

(Hidorin L-700, available (Hidorin L-700, available from fromChukyo Chukyo Yushi Yushi Co., Co., Ltd., Ltd., solidcontent solid content30%) 30%)(in(in terms terms ofof solid solid

content) were content) mixed,and were mixed, andwater waterwas wasadded added theretototoa asolid thereto solidcontent contentconcentration concentrationofof33%, 33%, followed by stirring, to prepare a heat-sealable layer coating material (concentration 33%). followed by stirring, to prepare a heat-sealable layer coating material (concentration 33%).

Thestyrene/butadiene The styrene/butadienecopolymer copolymer had had a solubilityininwater a solubility wateratat 25°C 25Cofof1010g/L g/Lororless. less.

[0093]

<Production ofheat-sealable <Production of heat-sealable paper> paper> Theobtained The obtainedheat-sealable heat-sealable layer layer coating coating material material was usedto was used to form formaa heat-sealable heat-sealable layer with an air knife coater on the W side of extensible paper having a basis weight of 82.9 layer with an air knife coater on the W side of extensible paper having a basis weight of 82.9

g/m2, aa thickness g/m², thickness of 123 m, of 123 andaa density µm, and density of of 0.67 g/cm³3 (( available 0.67 g/cm available from from Oji Oji Materia Co., Materia Co.,

Ltd., needle Ltd., needle unbleached kraft pulp: unbleached kraft pulp: 100% bymass, 100% by mass,Canadian Canadian standard standard freeness: freeness: 677677 mL,mL,

Clupakprocessing Clupak processingwas wasdone, done,smoothness smoothness F side: F side: 4 seconds, 4 seconds, W side: W side: 7 seconds) 7 seconds) so that so that thethe 2 heat-sealable coating amount of the heat-sealable layer after drying was 10 g/m , then, the heat-sealable coating amount of the heat-sealable layer after drying was 10 g/m², then, the

layer coating material was dried with a dryer at 130 to 160C, finally, a chilled roll was in layer coating material was dried with a dryer at 130 to 160°C, finally, a chilled roll was in

contact with the coated surface and a cotton roll was in contact with the non-coated surface so contact with the coated surface and a cotton roll was in contact with the non-coated surface so

as to achieve as to achieve a alinear linearload load of of 90 90 kg/cm, kg/cm, followed followed by heating by heating the the rolls to rolls to 40C 40°C and and one-stage one-stage

super calendering, to super calendering, to thereby thereby obtain obtain heat-sealable heat-sealable paper paper (smoothness (smoothness FF side: side: 88 seconds, seconds, W W

side: side: 64 64 seconds). Supercalendering seconds). Super calendering increased increased thesmoothness the smoothness and and improved improved printability printability

comparedtotopaper compared paperbefore beforecoating. coating.

[0094]

27 --

[Example

[Example 2]2]

A heat-sealable A heat-sealable layer layer was formedand was formed andsuper supercalendering calenderingwas was performed performed in the in the same same

mannerasasinin Example manner Example 1 1 except except thatthe that theextensible extensiblepaper paperwas waschanged changedto to extensiblepaper extensible paper having aa basis having basis weight of 78.3 weight of 78.3 g/m g/m²,, a thickness of 126 m, and a density of 0.62 g/cm 2 a thickness of 126 µm, and a density of 0.62 g/cm³3

(available (available from from Oji Oji Materia Co., Ltd., Materia Co., Ltd., needle needle unbleached kraft pulp: unbleached kraft pulp: 100% bymass, 100% by mass,Canadian Canadian standard freeness: 563 standard freeness: 563 mL, smoothness mL, smoothness F F side:1212seconds, side: seconds,W W side: side: 2929 seconds) seconds) andand thethe

coating amount of a heat-sealable layer after drying was set to 12 g/m², thereby2 to obtain heat- coating amount of a heat-sealable layer after drying was set to 12 g/m , thereby to obtain heat- sealable sealable paper paper (smoothness (smoothness FFside: side: 15 15 seconds, seconds,WWside: side:6161seconds). seconds).

[0095]

[Example

[Example 3]3]

mannerasasinin Example manner Example 1 1 except except thatthe that theextensible extensiblepaper paperwas waschanged changedto to heavy-duty heavy-duty

packagingpaper packaging paperhaving havinga abasis basisweight weightofof79.2 g/m2,aathickness 79.2g/m², thicknessof of 132 m,and 132µm, anda adensity densityofof 0.60 g/cm3 (available 0.60 g/cm³ (available from Oji Materia from Oji MateriaCo., Co., Ltd., Ltd., needle needle unbleached kraft pulp: unbleached kraft pulp: 100% 100%byby mass, Canadian mass, Canadianstandard standardfreeness: freeness:578 578mL, mL, smoothness smoothness F side: F side: 3 seconds, 3 seconds, W side: W side: 2 seconds, 2 seconds,

Clupakprocessing Clupak processingwas wasnot notperformed) performed)andand thethe coating coating amount amount of aofheat-sealable a heat-sealable layer layer after after 2 thereby to obtain heat-sealable paper (smoothness F side: 25 drying was drying wasset set to to 10 10 g/m g/m²,, thereby to obtain heat-sealable paper (smoothness F side: 25 seconds, Wside: seconds, W side: 65 65seconds). seconds).

[0096]

[Example

[Example 4]4]

Ninety eight Ninety eight parts parts of of an an aqueous dispersion of aqueous dispersion of aa commercially available ethylene- commercially available ethylene- acrylic acidcopolymer acrylic acid copolymer (glass (glass transition transition temperature: temperature: 45C) 45°C) (in terms(in of terms of solidand solid content) content) 2 and 2 parts of parts of an an aqueous dispersion of aqueous dispersion of aa commercially available carnauba commercially available carnaubawax wax(Michem (Michem LubeLube

160RPH, availablefrom 160RPH, available fromMichelman, Michelman, solid solid content content concentration: concentration: 25%25% by mass) by mass) (in terms (in terms of of

solid content)were solid content) were mixed, mixed, and water and water wasthereto was added addedwith thereto withsostirring stirring sosolid that the that content the solid content concentration was concentration was35%, 35%,totothereby therebyprepare preparea aheat-sealable heat-sealablelayer layer coating coating material material (concentration: (concentration: 35%). A heat-sealable 35%). A heat-sealable layer layer was was formed formed and and super super calendering calendering was was

performedininthe performed the same samemanner manneras as inin Example Example 2 except 2 except that that thethe obtained obtained heat-sealable heat-sealable layer layer

coating material coating material was used, to was used, to thereby thereby obtain obtain heat-sealable heat-sealable paper paper (smoothness (smoothness FFside: side: 88 seconds, Wside: seconds, W side: 82 82seconds). seconds).TheThe ethylene-acrylic ethylene-acrylic acid acid copolymer copolymer had had a solubility a solubility to to water water

of 10 g/L or less at 25C. of 10 g/L or less at 25°C.

[0097]

[Example

[Example 5]5]

mannerasasinin Example manner Example 1 1 except except that2 2parts that partsof of aa polyethylene polyethylenewax waxemulsion emulsion (Aquacer (Aquacer 531, 531,

28 --

available available from BYK,solid from BYK, solidcontent contentconcentration: concentration:45% 45%by by mass) mass) (in(in terms terms of of solidcontent) solid content) was added instead of 2 parts of the paraffin wax emulsion (in terms of solid content), to was added instead of 2 parts of the paraffin wax emulsion (in terms of solid content), to

prepare a heat-sealable layer coating material, to thereby obtain heat-sealable paper prepare a heat-sealable layer coating material, to thereby obtain heat-sealable paper

(smoothness (smoothness F Fside: side: 88 seconds, seconds, WWside: side:4242seconds) seconds)

[0098]

[Example

[Example 6]6]

Heat-sealable paper Heat-sealable paper (smoothness (smoothnessF Fside: side:1212seconds, seconds,W W side:4040seconds) side: seconds) was was obtained obtained

in the in the same mannerasasinin Example same manner Example 2 2 except except thatsuper that supercalendering calenderingwas was not not performed. performed.

[0099]

[Example

[Example 7]7]

mannerasasinin Example manner Example 1 1 except except thatthe that theparaffin paraffin wax waxemulsion emulsion was was notnot added, added, to to thereby thereby

obtain obtain heat-sealable heat-sealable paper paper (smoothness (smoothness FFside: side: 88 seconds, seconds, WWside: side: 60 60seconds). seconds).

[0100]

[Example

[Example 8]8]

Heat-sealable paper (smoothness Heat-sealable paper (smoothnessF Fside: side:88seconds, seconds,WW side:1212seconds) side: seconds)was was obtained obtained

in in the the same same manner asinin Example manner as Example 1 1 except except that1010parts that partsofofan anaqueous aqueousdispersion dispersionofofkaolin kaolin (average (average particle size:8 8µm,m, particlesize: aspect aspect ratio: ratio: 80100) 80 to to 100) havinghaving a solida content solid content concentration concentration of of 50% (interms 50% (in terms of of solid solid content), content), 88 parts 88 parts of anof an aqueous aqueous dispersion dispersion of a styrene/butadiene of a styrene/butadiene

copolymer(available copolymer (availablefrom fromZeon Zeon Corporation, Corporation, Nipol Nipol latex latex LX407S12, LX407S12, solidsolid content content

concentration: 46%, glass transition temperature: 18C (catalog value)) (in terms of solid concentration: 46%, glass transition temperature: 18°C (catalog value)) (in terms of solid

content), and content), and 2 2 parts parts of ofa aparaffin paraffinwax waxemulsion emulsion (available (available from from Chukyo YushiCo., Chukyo Yushi Co.,Ltd., Ltd., Hidorin L-700, Hidorin L-700,solid solid content content concentration: concentration: 30%) 30%)(in (interms termsofof solid solid content) content) were used to were used to prepare a heat-sealable layer coating material. prepare a heat-sealable layer coating material.

[0101]

[Example

[Example 9]9]

mannerasasinin Example manner Example 1 1 except except that2 2parts that partsof of aa carnauba carnaubawax waxemulsion emulsion (Michem (Michem Lube Lube

solid content)was solid content) was added added instead instead of 2 of 2 parts parts of theofparaffin the paraffin wax emulsion wax emulsion (in terms (in terms of solid of solid

content), to prepare a heat-sealable layer coating material, to thereby obtain heat-sealable content), to prepare a heat-sealable layer coating material, to thereby obtain heat-sealable

paper (smoothness paper (smoothnessF Fside: side:88seconds, seconds,WWside: side:6464seconds). seconds).

[0102]

[Example 10]

- 29 --

mannerasasinin Example manner Example 2 2 except except that2 2parts that partsof of aa polyethylene polyethylenewax waxemulsion emulsion (Aquacer (Aquacer 531, 531,

available available from BYK,solid from BYK, solidcontent contentconcentration: concentration:45% 45%by by mass) mass) (in(in terms terms of of solidcontent) solid content) was added instead of 2 parts of the paraffin wax emulsion (in terms of solid content) to was added instead of 2 parts of the paraffin wax emulsion (in terms of solid content) to

(smoothness (smoothness F Fside: side: 15 15seconds, seconds,WWside: side:4242seconds). seconds).

[0103]

[Example 11]

mannerasasinin Example manner Example 1 1 except except thatthe that theextensible extensiblepaper paperwas waschanged changedto to extensiblepaper extensible paper having aa basis having basis weight of 100.0 weight of g/m2, aa thickness 100.0 g/m², thickness of 149 m, of 149 andaadensity µm, and density of of 0.67 g/cm3 0.67 g/cm³ (available (available from from Oji Oji Materia Co., Ltd., Materia Co., Ltd., needle needle unbleached kraft pulp: unbleached kraft pulp: 100% bymass, 100% by mass,Canadian Canadian standard freeness: 677 standard freeness: 677 mL, Clupakprocessing mL, Clupak processingwaswas performed, performed, smoothness smoothness F side: F side: 7 seconds, 7 seconds,

Wside: W side: 18 18 seconds), seconds), to to thereby thereby obtain obtain heat-sealable heat-sealable paper paper (smoothness (smoothness FFside: side: 88 seconds, seconds, WW side: 57seconds). side: 57 seconds).

[0104]

[Example 12]

Heat-sealable paper Heat-sealable paper (smoothness (smoothnessF Fside: side:1515seconds, seconds,W W side:2424seconds) side: seconds) was was obtained obtained

in the in the same mannerasasinin Example same manner Example 2 2 except except that1010parts that partsofofan anaqueous aqueousdispersion dispersionofofkaolin kaolin (average (average particle size:8 8µm,m, particlesize: aspect aspect ratio: ratio: 80100) 80 to to 100) havinghaving a solida content solid content concentration concentration of of 50% (interms 50% (in terms of of solid solid content), content), 88 parts 88 parts of anof an aqueous aqueous dispersion dispersion of a styrene/butadiene of a styrene/butadiene

content), and content), and 2 2 parts partsof ofa aparaffin paraffinwax waxemulsion emulsion (available (available from from Chukyo YushiCo., Chukyo Yushi Co.,Ltd., Ltd., Hidorin L-700, Hidorin L-700,solid solid content content concentration: concentration: 30%) 30%)(in (interms termsofof solid solid content) content) were used to were used to prepare a heat-sealable layer coating material. prepare a heat-sealable layer coating material.

[0105]

[Example 13]

mannerasasinin Example manner Example 2 2 except except that2 2parts that partsof of aa carnauba carnaubawax waxemulsion emulsion (Michem (Michem Lube Lube

paper (smoothness paper (smoothnessF Fside: side:15 15seconds, seconds,WW side:6262seconds). side: seconds).

[0106]

- 30 --

[Comparative Example

[Comparative Example 1] 1]

mannerasasinin Example manner Example 1 1 except except thatthe that theextensible extensiblepaper paperwas waschanged changedto to unbleached unbleached light- light-

duty packaging duty packagingpaper paperhaving havinga abasis basisweight weightofof80.5 g/m2,a athickness 80.5g/m², thicknessof of 114 m,and 114µm, anda a 3 density of0.71 density of 0.71g/cm³ g/cm (available (available from from Oji Materia Oji Materia Co.,needle Co., Ltd., Ltd.,unbleached needle unbleached kraft pulp /kraft pulp /

leaf bleached leaf bleached kraft kraft pulp pulp == 80/20 80/20 (mass ratio), Canadian (mass ratio), Canadian standard standard freeness: freeness: 478 478 mL, mL,

smoothnessF Fside: smoothness side:17 17seconds, seconds,WW side:1616seconds), side: seconds),totothereby therebyobtain obtainheat-sealable heat-sealablepaper paper (smoothness (smoothness F Fside: side: 89 89seconds, seconds,WWside: side:219 219seconds). seconds).

[0107]

[Comparative Example

[Comparative Example 2] 2]

Unbleached light-dutypackaging Unbleached light-duty packaging paper paper having having a basisweight a basis weight of of 70.0 70.0 g/m2a, athickness g/m², thickness of 100 of m,and 100 µm, andaadensity density of of 0.70 g/cm3(available 0.70 g/cm³ (available from fromOji Oji Materia MateriaCo., Co.,Ltd., Ltd., needle needle unbleachedkraft unbleached kraft pulp/leaf pulp/leaf bleached kraft pulp bleached kraft pulp = = 80/20 (massratio), 80/20 (mass ratio), Canadian standard Canadian standard

freeness: 478 freeness: 478 mL, smoothness mL, smoothness F F side:1616seconds, side: seconds,W W side:1414 side: seconds) seconds) waswas subjected subjected to to melt melt

extrusion lamination extrusion so that lamination so that the the thickness thickness of ofpolyethylene polyethylene was 20 m, was 20 to thereby µm, to thereby form form 2 polyethylenelaminated polyethylene laminatedpaper paperhaving havinga abasis basisweight weightofof89.2 89.2g/m² g/m(smoothness (smoothness F side: F side: 1616

seconds, Wside: seconds, W side: 140 140seconds). seconds).

[0108]

[Comparative Example

[Comparative Example 3] 3]

mannerasasinin Example manner Example 3 3 except except thatananaqueous that aqueous dispersion dispersion ofof anan ethylene/vinylacetate ethylene/vinyl acetate copolymer (available copolymer (available from fromSumika SumikaChemtex Chemtex Company, Company, Limited, Limited, SUMIKAFLEX 470HQ, SUMIKAFLEX 470HQ,

solid content:55%, solid content: 55%, glass glass transition transition temperature: temperature: 0C (catalog 0°C (catalog value)) value)) was used was used instead of instead the of the aqueousdispersion aqueous dispersionof of the the styrene/butadiene styrene/butadiene copolymer copolymerasasthe theheat-sealable heat-sealablelayer layer coating coating material, and material, and the the paraffin paraffinwax wax emulsion wasnot emulsion was notused, used,to to thereby thereby obtain obtain heat-sealable heat-sealable paper paper

(smoothness (smoothness F Fside: side: 25 25 seconds, seconds,WWside: side:5656seconds). seconds).

[0109]

[Comparative Example

[Comparative Example 4] 4]

mannerasasinin Example manner Example 1 1 except except thatthe that theextensible extensiblepaper paperwas waschanged changedto to one-side one-side glazed glazed kraft kraft

paper having paper havingaa basis basis weight weight of of 78.2 g/m2, aa thickness 78.2 g/m², thickness of 100 m, of 100 andaa density µm, and density of of 0.78 g/cm3 0.78 g/cm³ (available from (available from Oji Oji Materia Materia Co., Co., Ltd.,Ltd., needle needle bleached bleached kraft pulp/leaf kraft pulp/leaf bleached bleached kraft pulp kraft = pulp = 35/65 (massratio), 35/65 (mass ratio), Canadian standardfreeness: Canadian standard freeness: 578 578 mL, mL,smoothness smoothness F side:120120 F side: seconds, seconds, W W

side: side: 18 18 seconds), seconds), to tothereby thereby obtain obtainheat-sealable heat-sealablepaper paper(smoothness (smoothness F F side: side: 300 300 seconds, seconds, W W

side: 291seconds). side: 291 seconds).

31 --

[0110]

[Comparative Example

[Comparative Example 5] 5]

mannerasasinin Example manner Example 1 1 except except thatthe that theextensible extensiblepaper paperwas waschanged changedto to one-side one-side bleached bleached

kraft paper having a basis weight of 50.7 g/m , a thickness of 61 m, and a density of 0.83 2 kraft paper having a basis weight of 50.7 g/m², a thickness of 61 µm, and a density of 0.83

g/cm³3 (available g/cm (available from Oji F-Tex from Oji F-TexCo., Co.,Ltd., Ltd., leaf leaf bleached bleached kraft kraft pulp: pulp: 100% bymass, 100% by mass,Canadian Canadian standard freeness: 420 standard freeness: 420 mL, smoothness mL, smoothness F F side:430 side: 430seconds, seconds,W W side: side: 16 16 seconds, seconds, Clupak Clupak

processing was processing wasnot notperformed), performed),totothereby therebyobtain obtainheat-sealable heat-sealable paper paper(smoothness (smoothnessF Fside: side:963 963 seconds, Wside: seconds, W side: 219 219seconds). seconds).

[0111]

[Comparative Example

[Comparative Example 6] 6]

mannerasasinin Example manner Example 1 1 except except thatthe that theextensible extensiblepaper paperwas waschanged changedto to thickglassine thick glassinepaper paper having aa basis having basis weight of 30.6 weight of 30.6 g/m g/m²,, a thickness of 30 m, and a density of 1.01 g/cm 2 a thickness of 30 µm, and a density of 1.01 g/cm³3

(available (available from from Oji Oji F-Tex Co., Ltd., F-Tex Co., Ltd., needle needle bleached kraft pulp: bleached kraft pulp: 100% bymass, 100% by mass,smoothness smoothnessF F

side: side: 1,300 1,300 seconds, seconds, W side: 1,350 W side: 1,350 seconds), seconds), to to thereby thereby obtain obtain heat-sealable heat-sealable paper paper

(smoothness (smoothness F Fside: side: 1,700 1,700seconds, seconds,WWside: side:1,500 1,500seconds). seconds).

[0112]

[Measurement method]

Theobtained The obtainedheat-sealable heat-sealable paper paperwas wasused usedtotoperform performthe thefollowing followingmeasurements. measurements. <Smoothness> <Smoothness>

TheOken The Okensmoothness smoothness waswas measured measured according according toP8155:2010 to JIS JIS P8155:2010 to determine to determine a a value of the value of the smoothness. smoothness. TheThe smoothness smoothness of the of the paper paper substrate substrate was was measured measured in same in the the same mannerasasdescribed manner describedabove. above.

[0113]

Each of the Clark stiffnesses of paper in the longitudinal direction and the transverse Each of the Clark stiffnesses of paper in the longitudinal direction and the transverse

direction was direction measuredaccording was measured accordingtotoJIS JISP P8143:2009, 8143:2009, and and both both of of them them were were usedused to to determine determine aa geometric geometricmean, mean,and andthethegeometric geometric mean mean was was defined defined as aas a value value of Clark of Clark

stiffness stiffnessgeometric geometric mean. mean.

[0114]

<Tear indexofof heat-sealable <Tear index heat-sealable paper> paper> Thetearing The tearing resistance resistance of of the theheat-sealable heat-sealablepaper paperwas was measured accordingtotoJIS measured according JIS PP 8116:2000. Each 8116:2000. Each of the of the tearing tearing resistancesininthe resistances thelongitudinal longitudinaldirection direction and and the the transverse transverse direction was direction measured,and was measured, andthe theobtained obtainedvalue valuewas wasdivided dividedbybya abasis basisweight, weight,and andthe thethus- thus-

- 32 --

obtained value was obtained value wasdefined definedasasaa tear tear index. From index. From thethe obtained obtained tearindexes tear indexes inin the the

longitudinal direction and the transverse direction, a longitudinal and transverse geometric longitudinal direction and the transverse direction, a longitudinal and transverse geometric

meanwas mean wasdetermined. determined.

[0115]

<Burst indexof <Burst index of heat-sealable heat-sealable paper> paper>

Thebursting The bursting strength strength of of the the heat-sealable heat-sealable paper paper was was measured accordingtotoJIS measured according JISPP 8112:2008. 8112:2008. TheThe obtained obtained value value was was divided divided by a by a basis basis weight, weight, and and thus-obtained thus-obtained valuevalue was was

defined as a burst index. defined as a burst index.

[0116]

Thetest The test was performedaccording was performed accordingtotoJIS JISZ1717:2019. Z1717:2019.

[0117]

<Measurement <Measurement of of heat heat sealingpeel sealing peelstrength> strength> One set of two heat-sealable papers was stacked so that heat-sealable layers face each One set of two heat-sealable papers was stacked so that heat-sealable layers face each

other other and and heat-sealed heat-sealed using using a a heat heat seal sealtester tester(TP-701-B, (TP-701-B,available availablefrom from TESTER SANGYO TESTER SANGYO

CO,LTD.) CO, LTD.)under under theconditions the conditionsofof150°C, 150C, 0.2MPa, 0.2 MPa, andand oneone second. second. The heat-sealed The heat-sealed test test specimens wereleft specimens were left standing standing in in aa room at aa temperature room at temperature of 23C±1°C of 23°C 1Cand anda ahumidity humidityof of 50% 50%

 2% ± 2%for for 44 hours hoursor or more. more.Subsequently, Subsequently, the the test test specimen specimen heat-sealed heat-sealed waswas cut cut intointo a width a width

of 15 of 15 mm andT-peeled mm and T-peeled using using a tensiletester a tensile tester at at aa tensile tensilespeed speedofof300 300mm/min, andthe mm/min, and the maximum load maximum load recorded recorded was was taken taken as aasheat a heat sealing sealing peel peel strength. strength.

[0118]

<Drop test using <Drop test using sand> sand> Twosheets Two sheetsofofheat-sealable heat-sealable paper paperwith with400 400square squaremillimeters millimeterswere wereplaced placedwith withthethe surfaces ofthe surfaces of theheat-sealable heat-sealable paper paper facing facing each each other,other, andsealing and heat heat sealing was performed was performed at three at three sides, approximately sides, approximately 2 kg2 of kgsand of sand was filled was filled thereinto, thereinto, and theand the remaining remaining oneheat- one side was side was heat- sealed, to sealed, to thereby thereby produce produce a a packaging bagfilled packaging bag filled with with the the contents. contents. AAdrop droptest testwas wasthen then conductedononthis conducted this according accordingtoto JIS JIS ZZ 0202:2017. 0202:2017.FiveFive bags bags werewere mademade in same in the the same manner manner

as as described described above for the above for the drop drop test. Thenumber test. The numberof of tornbags, torn bags,the thenumber numberof of broken broken bags, bags,

and the number and the ofopened number of openedheat-sealed heat-sealedportions portionsininall all the the bags bags were totaled, followed were totaled, by followed by

determination based on the following criteria (only A is acceptable). determination based on the following criteria (only A is acceptable).

A: In the drop test, torn paper, a broken bag, and opening of the heat-sealed portions A: In the drop test, torn paper, a broken bag, and opening of the heat-sealed portions

were not found at all. were not found at all.

B: In the B: In thedrop droptest, test,the thetotal totalnumber number of torn of torn paper paper ornumber or the the number ofheat-sealed of opened opened heat-sealed portions was 1 or more but 4 or less. portions was 1 or more but 4 or less.

- 33 --

C: In the C: In thedrop droptest, test,the thetotal totalnumber number of torn of torn paper paper ornumber or the the number ofheat-sealed of opened opened heat-sealed portions was portions was 55 or or more. more.

[0119]

<Drop test using <Drop test using gravel> gravel> Twosheets Two sheetsofofheat-sealable heat-sealable paper paper with with400 400square squaremillimeters millimeterswere wereplaced placedwith withthethe surfaces ofthe surfaces of theheat-sealable heat-sealable paper paper facing facing each each other,other, andsealing and heat heat sealing was performed was performed at three at three sides, approximately sides, approximately 2 kg2 of kggravel of gravel (sharper (sharper thanwas than sand) sand) wasthereinto, filled filled thereinto, and the remaining and the remaining

one side was one side heat-sealed, to was heat-sealed, to thereby thereby produce produce aa packaging bagfilled packaging bag filled with with the the contents. contents. A A

drop test drop test was was then then conducted onthis conducted on this according according to to JIS JIS Z 0202:2017.FiveFive Z 0202:2017. bags bags were were mademade in in the same the mannerasasdescribed same manner describedabove above forthe for thedrop droptest. test. TheThe number number of torn of torn bags, bags, the the number number

of broken bags, and the number of opened heat-sealed portions in all the bags were totaled, of broken bags, and the number of opened heat-sealed portions in all the bags were totaled,

followed by determination based on the following criteria (only A is acceptable). followed by determination based on the following criteria (only A is acceptable).

A: In the drop test, torn paper and a broken bag were not found at all. A: In the drop test, torn paper and a broken bag were not found at all.

B: In the drop test, the total number of torn paper or the number of broken bags was 1 B: In the drop test, the total number of torn paper or the number of broken bags was 1

or more but 4 or less. or more but 4 or less.

C: In the C: In thedrop droptest, test,the thetotal totalnumber number of torn of torn paper paper ornumber or the the number ofbags of broken broken was 5bags was 5

or more. or more.

[0120]

<Ease of opening <Ease of openingtest> test> The heat-sealed portion of a packaging bag similar to that used in the drop test was The heat-sealed portion of a packaging bag similar to that used in the drop test was

pulled in both directions perpendicular to the heat-sealed surface without tearing (by pulling pulled in both directions perpendicular to the heat-sealed surface without tearing (by pulling

both sheets of heat-sealed paper in opposite directions so as to peel the heat-sealed layers both sheets of heat-sealed paper in opposite directions so as to peel the heat-sealed layers

from each from eachother), other), and the ease and the ease of of opening at the opening at the time time of ofopening opening was evaluated as was evaluated as follows. follows. A: AApackaging A: packagingbag bagcould could bebe easilyopened. easily opened. B: A packaging bag was very tight and is difficult to open. B: A packaging bag was very tight and is difficult to open.

[0121]

Ten sheets of the heat-sealable paper were laminated so that the coated surface and the Ten sheets of the heat-sealable paper were laminated so that the coated surface and the

non-coatedsurface non-coated surfacewere wereinincontact contact with witheach eachother, other, and and were werepressed pressedatat aa pressure pressure of of 20 20

2 15 hours while the sheets were heated to 40°C in the longitudinal direction with a kgf/cm for 15 hours while the sheets were heated to 40C in the longitudinal direction with a kgf/cm² for

hot press hot press machine. After machine. After thepressure the pressurewas was released,the released, thepaper paperwas was taken taken out.Then, out. Then, the the result obtained result obtained when the sheets when the sheets were peeled with were peeled withhand handwas wasevaluated. evaluated. A: Neither A: Neither breakage breakagenor norpaper paperpeeling peelingwas wasfound. found. B: B: Either Either breakage or paper breakage or paper peeling peeling was wasfound. found.

[0122]

34 --

Heat-sealable paper was Heat-sealable paper wascontinuously continuouslymade made into into bags bags using using a high-speed a high-speed transverse transverse

pillow packing pillow packingmachine machine(Wrapper FW3410,available (Wrapper FW3410, available from from FUJI FUJI MACHINERY MACHINERY CO.,CO.,

LTD.).At At LTD.). thistime, this time,nonocontents contentswere were put put intothe into thebag, bag,but butananempty emptybag bagwaswas used used forfor

molding,and molding, andthe the appearance appearanceand andthe therunnability runnabilitywere werechecked checkedto to determine determine thethe followings. followings.

Here, "continuous Here, "continuousbag bagmaking making was was impossible" impossible" means means a state a state in which in which wrinkles wrinkles werewere

generated, generated, a a state stateininwhich which aabag bag could could not not formed due to formed due to meandering, oraa paper meandering, or paper break break occurred. The occurred. The phrase phrase "bad "bad appearance" appearance" means means the presence the presence of wrinkles, of wrinkles, misalignment misalignment of theof the

sealed portion,orordeformation sealed portion, deformation of bag of the the (A bag and(A andacceptable). B are B are acceptable). A: Continuous A: Continuousbag bagmaking making waswas possible, possible, andand thethe appearance appearance of the of the bagbag waswas good. good.

B: B: Continuous bagmaking Continuous bag makingwaswas possible, possible, butbut thethe appearance appearance of of thethe bag bag waswas slightly slightly defective. defective.

C: C: Continuous bagmaking Continuous bag makingwaswas impossible. impossible.

[0123]

Table 1 Heat-sealable paper Heat-sealable layer Paper substrate beating after Freeness stiffness/basis Clark smoothness side W packaging Automatic strength peel sealing Heat smoothness side W smoothness side F resistance Blocking stiffness Clark smoothness Fside (gravel) test Drop strength Piercing formability Ease of opening Drop test (sand) Burst index Tear index Thickness Basis weight Thickness Basis weight weight Density Density Kind Table 1 layer Heat-sealable Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Heavy-duty Extensible Extensible Extensible Extensible Extensible Extensible Extensible Extensible Extensible Extensible Extensible Extensible Kind - packaging paper paper paper paper paper paper paper paper paper paper paper paper paper Freeness after beating mL 677 563 578 563 677 563 677 677 677 563 677 563 563 Paper substrate

mean geometric transverse mean geometric transverse mean geometric transverse (mN-m²/g) Longitudinal (mN-m²/g) Transverse agent main of Kind (m²/g) Longitudinal (m²/g) Transverse g/m2 and Longitudinal Basis weight 82.9 78.3 79.2 78.3 82.9 78.3 82.9 82.9 82.9 78.3 100.0 78.3 78.3 Longitudinal and Longitudinal and Longitudinal Transverse Lubricant N/15mm kPa.m²/g (mN-m²/g) Pigment Second Second Tg (°C) Second Second m (m²/g) g/cm³ g/cm³ g/m² g/m² Thickness - I - - - 123 126 132 126 123 µm 126 123 123 123 µm126 mL149 - 126 126 Density g/cm3 N 0.67 0.62 0.60 0.62 0.67 0.62 0.67 0.67 0.67 0.62 0.67 0.62 0.62 F side smoothness Second 4 12 3 12 4 12 4 4 4 12 7 12 12 Extensible Example 1 Paraffin W side smoothness 6.0 Second 14.0 6.0 17.9 720.7 15.5 29 0.49 0.52 2 0.47 45.9 29 43.5 48.4 7 0.78 120 29 93.0 None wax 7 7 SBR 7 0.67 123 29 82.9 677 18 paper 29 29 64 18 A A A A AKind of main agent 8 7 4SBR Heat-sealable layer

Ethylene- SBR SBR SBR SBR SBR SBR SBR SBR SBR SBR SBR acrylic acid Paraffin Extensible Example 2 None paper 5.0 Tg12.9 (C)4.2 17.2 18 20.0 14.8 18 0.49 0.43 18 0.54 43.8 45 39.2 48.9 61 18 15 0.75 120 18 90.2 wax 18 18 18 SBR 29 12 18 0.62 126 18 78.3 563 18 18 18 Heat-sealable A A layer A A A Lubricant Paraffin Paraffin Paraffin Carnauba PE wax Paraffin None Paraffin Carnauba PE wax Paraffin Paraffin Carnauba wax wax wax wax 167.9 wax Paraffin wax wax wax paper

packaging wax Heavy-duty Example 3 wax 0.56 91.2 49.5 0.69 89.2 None wax 0.60 79.2 7.0 10.5 12.9 14.5 11.5 1.02 1.88 130 SBR 132 578 Pigment3.8 None None None None 65 None 25 None None 18 Kaolin None None None Kaolin None Basis weight C A A B A g/m2 93.0 90.2 89.2 90.3 93.1 90.2 93.0 93.0 93.0 2 3 90.2 110.2 90.2 90.2 m Ethylene- Thickness 120 120 130 120 120 0.75 140 None 120 120 120 0.62 120 140 120 120 Carnauba acrylic acid Extensible Example 4 paper 0.49 0.45 0.54 44.2 40.2 48.6 6.5 13.1 4.4 17.5 19.8 15.5 120 90.3 wax 126 78.3 563 Density g/cm3 0.78 0.75 0.69 0.75 82 0.78 0.64 0.78 45 0.78 29 120.78 0.75 0.79 0.75 0.75 A F side smoothness A A A A Second 8 15 25 8 8 8 12 8 8 8 15 8 15 15 - 35 W side smoothness Second 64 61 65 82 43.5 42 0.78 40 None 60 12 64 0.67 42 57 24 Example 5 62 Extensible PE wax paper 14.0 17.6 20.2 15.3 0.50 0.53 0.47 46.5 49.7 93.1 SBR 82.9 6.5 6.1 120 123 677 Longitudinal 43.5 48.9 167.9 48.6 42 43.5 59.0 43.5 18 43.5 43.5 48.7 70.4 48.0 48.0 A A A A A Transverse 48.4 39.2 49.5 40.2 49.7 8 52.6 48.4 48.4 448.4 7 39.4 67.6 42.2 42.2 Clark stiffness Longitudinal and Example 6 Extensible Paraffin 4.6 13.1 4.3 18.0 45.9 20.8 15.6 43.8 0.62 0.58 91.2 0.65 55.7 44.2 52.6 59.0 46.5 0.64 140 55.7 90.2 None wax 45.9 45.9 SBR 45.9 0.62 126 43.8 78.3 69.0 563 paper 45.0 45.0 transverse geometric mean 40 12 18 29 12 B A A A A Longitudinal (m2/g) 0.47 0.54 1.88 0.54 0.47 0.65 0.47 0.47 0.47 0.54 0.64 0.53 0.53 Transverse (m2/g) 0.52 0.43 0.56 0.45 0.53 0.58 0.52 0.52 0.52 0.44 0.61 Extensible 0.47 Example 7 0.47 Clark stiffness/basis Heat-sealable paper

20.7 0.49 0.52 0.47 45.9 48.4 43.5 0.78 93.0 None None 0.67 82.9 paper 6.8 14.0 17.9 15.5 SBR weight Longitudinal and 6.0 60 120 18 123 677 B B A A A transverse geometric mean 0.49 0.49 1.02 0.49 0.50 8 0.62 0.49 0.49 7 40.49 0.49 0.63 0.50 0.50 (m2/g) Paraffin Extensible Example 8 Kaolin 2 Longitudinal 5.6 14.0 (mNm /g) 6.0 17.9 15.5 20.7 15.5 14.8 0.49 0.52 11.5 0.47 45.9 15.5 48.4 43.5 15.3 0.78 120 15.6 93.0 wax 15.5 15.5 SBR 15.5 0.67 123 14.8 82.9 14.2 677 paper 14.3 14.3 12 18 A A A A A Transverse (mNm2/g) 20.7 20.0 14.5 19.8 20.2 8 20.8 20.7 20.7 7 420.7 20.0 23.0 19.6 19.8 Tear index Longitudinal and Carnauba Extensible Example 9 transverse geometric 6.0 14.0 6.0 mean 17.9 17.9 20.7 15.5 17.2 0.49 0.52 12.9 0.47 45.9 17.5 48.4 43.5 17.6 0.78 120 18.0 93.0 None wax 17.9 17.9 SBR 17.9 0.67 123 17.2 82.9 18.1 677 paper 16.7 16.8 64 18 A A A A A (mNm2/g) Burst index kPam2/g 6.0 4.2 3.8 4.4 6.1 8 4.3 6.0 6.0 7 4 6.0 4.2 4.8 4.2 4.2 Example 10 Extensible Piercing strength N 4.2 14.0 12.9 0.44 10.5 13.1 14.0 13.1 PE wax 5.5 13.0 17.2 20.0 14.8 0.49 0.54 43.8 39.4 48.7 0.75 120 90.2 None 14.0 14.0 SBR 14.0 0.62 13.0 126 78.3 16.9 563 paper 12.9 12.9 42 15 29 12 Heat sealing Apeel A strength N/15mm 6.0 5.0 7.0 6.5 6.5 4.6 6.8 18 5.6 6.0 5.5 7.0 5.5 6.0 A A A Drop test (sand) - A A A A A A A A A A A Extensible

A Example 11

A Paraffin Drop test (gravel) - 4.8 7.0 16.9 18.1 A23.0 14.2 A 0.63 0.61 B 0.64 69.0 A 67.6 70.4 A 0.79 140 A110.2 None wax A A SBR A 0.67 149 A 100.0 677 A paper A A 57 18 18 A A Ease of opening A A A - A A A A A 8 A A A 7AA A A A A Blocking resistance - A A A A A A B A A A A Example 12

A Extensible Paraffin Automatic packaging Kaolin paper 5.5 - 12.9 4.2 16.7 A19.6 14.3 A 0.50 0.47 C 0.53 45.0 A 42.2 48.0 24 A 0.75 120 90.2 B wax B 18 A SBR 29 12A 0.62 126 A 78.3 563 A A A formability 15 A A A A A Example 13 Carnauba Extensible 0.50 0.47 0.53 45.0 42.2 48.0 0.75 90.2 None 0.62 paper 6.0 12.9 4.2 16.8 19.8 14.3 120 wax SBR 126 78.3 563 62 15 18 29 12 A A A A A

36 --

[0124]

Table 22 Table Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Example1 1 Example Example2 2 Example Example3 3 Example Example Example 4 4 Example5 5 Example Example6 6 Example

Unbleached Unbleached Unbleached Unbleached Heavy- Heavy- One-side One-side One-side One-side Thick light-duty light-duty light-duty light-duty duty glazed glazed Thick duty glazed glazed Kind Kind - glassine glassine - packaging packaging packaging packaging packaging packaging kraft kraft kraft kraft paper paper paper paper paper paper paper paper paper paper paper paper Freeness after beating Freeness after beating mL mL 478 478 478 478 578 578 578 578 420 420 -- Paper Paper Basis weight Basis weight g/m²2 g/m 80.5 80.5 70.0 70.0 79.2 79.2 78.2 78.2 50.7 50.7 30.6 30.6 substrate substrate Thickness Thickness m 114 114 100 100 132 132 100 100 61 61 30 30 µm Density Density g/cm³3 g/cm 0.71 0.71 0.70 0.70 0.60 0.60 0.78 0.78 0.83 0.83 1.01 1.01

F side smoothness F side smoothness Second Second 17 17 16 16 33 120 120 430 430 1300 1300 Wside W side smoothness smoothness Second Second 16 16 14 14 2 2 18 18 16 16 1350 1350 Kind of main Kind of main SBR PE- PE- Ethylene- Ethylene- SBR SBR SBR agent agent SBR laminated laminated vinyl acetate vinyl acetate SBR SBR SBR Heat- Heat- Heat-sealable sealable sealable Heat-sealable Tg (°C) Tg (C) 18 18 -- 00 18 18 18 18 18 18 layer layer layer layer Paraffin Paraffin Paraffin Paraffin Paraffin Paraffin Paraffin Paraffin Lubricant Lubricant None None None None wax wax wax wax wax wax wax wax Pigment Pigment None None None None None None None None None None None None Basis weight Basis weight g/m²2 g/m 90.5 90.5 89.2 89.2 89.3 89.3 88.9 88.9 60.2 60.2 40 40 Thickness Thickness m 115 115 123 123 130 130 95 95 62 62 40 40 µm Density Density g/cm3 g/cm³ 0.79 0.79 0.73 0.73 0.69 0.69 0.94 0.94 0.97 0.97 1.00 1.00

F side smoothness F side smoothness Second Second 89 89 16 16 25 25 300 300 963 963 1700 1700 W side smoothness W side smoothness Second Second 219 219 140 140 56 56 291 291 219 219 1500 1500 Longitudinal Longitudinal 158.0 158.0 130.0 130.0 168.2 168.2 40.2 40.2 40.2 40.2 10.3 10.3

Transverse Transverse 57.6 57.6 57.3 57.3 50.6 50.6 18.3 18.3 18.3 18.3 4.4 4.4 Clark stiffness Clark stiffness Longitudinal Longitudinal and transverse and transverse 95.4 95.4 86.3 86.3 92.3 92.3 27.1 27.1 27.1 27.1 6.7 6.7 geometric mean geometric mean

longitudinal longitudinal (m2/g) (m²/g) 1.75 1.75 1.46 1.46 1.88 1.88 0.45 0.45 0.67 0.67 0.26 0.26

Transverse Transverse Clark Clark (m 2/g) (m²/g) 0.64 0.64 0.64 0.64 0.57 0.57 0.21 0.21 0.30 0.30 0.11 0.11 stiffness/Basis stiffness/Basis

weight weight Longitudinal Longitudinal and transverse and transverse 1.05 1.05 0.97 0.97 1.03 1.03 0.30 0.30 0.45 0.45 0.17 0.17 Heat- Heat- geometric mean geometric mean 2/g) sealable sealable (m (m²/g)

paper paper Longitudinal Longitudinal 2/g) 12.4 12.4 10.8 10.8 11.5 11.5 7.1 7.1 6.6 6.6 4.1 4.1 (mNm (mN.m²/g)

Transverse Transverse (mNm2/g) (mN-m²/g) 16.0 16.0 14.9 14.9 14.5 14.5 7.5 7.5 7.2 7.2 4.5 4.5 Tear index Tear index Longitudinal Longitudinal and transverse and transverse 14.1 14.1 12.7 12.7 12.9 12.9 7.3 7.3 6.9 6.9 4.3 4.3 geometric mean geometric mean 2/g) (mNm (mN-m²/g)

Burst index Burst index kPam2/g kPa-m²/g 2.6 2.6 3.5 3.5 3.9 3.9 3.7 3.7 4.2 4.2 3.6 3.6

Piercing strength Piercing strength N N 8.9 8.9 9.5 9.5 10.5 10.5 5.9 5.9 4.7 4.7 1.8 1.8

Heat sealing Heat sealing peel peel N/15mm 5.0 5.0 20.0 20.0 12.0 12.0 5.0 5.0 4.8 4.8 3.3 3.3 strength strength N/15mm Droptest Drop test (sand) (sand) -- C C B B A C C C C C C A Drop test(gravel) Drop test (gravel) C C C C B B C C C C C C Ease Ease of of opening opening -- A A B B B B A A A A A A Blocking resistance Blocking resistance -- A A A A A A A A A A A A Automaticpackaging Automatic packaging formability formability -- C C B B C C A A A A A A

[0125]

- 37 --

FromTable From Table1,1,the thepackaging packagingbags bagsobtained obtained from from thethe heat-sealablepaper heat-sealable paper ofof Examples Examples 1 1 to 13 to 13 were excellent in were excellent in drop drop impact resistance and impact resistance and were preventedfrom were prevented frombeing beingtorn. torn.In In addition, addition, these these packaging bags were packaging bags wereeasily easily opened openedatat the the time time of of opening. opening.

In contrast, In contrast,from from Table Table 2, 2, the thepackaging packaging bag bag obtained fromthe obtained from the heat-sealable heat-sealable paper paper of of ComparativeExample Comparative Example 1 having 1 having a burst a burst index index of of less less than than 3.0 kPam2/g 3.0kPa.m²/g waswas deteriorated deteriorated in in

drop impact drop impactresistance resistance and and was wastorn. torn. TheThe packaging packaging bag bag obtained obtained fromfrom the heat-sealable the heat-sealable

paper of paper of Comparative Example Comparative Example 2, 2, which which was was obtained obtained by providing by providing a PE alayer PE layer on unbleached on unbleached

light-duty packaging light-duty paperthrough packaging paper throughlamination laminationand andhad hada aheat heatsealing sealingpeel peelstrength strength of of more more than 10 than N/15mm, 10 N/15 mm,waswas deteriorated deteriorated inin dropimpact drop impact resistanceand resistance andease easeofofopening. opening. Moreover,the Moreover, thepackaging packagingbag bag obtained obtained from from thethe heat-sealable heat-sealable paper paper of of Comparative Comparative Example Example

33 having having aa heat heat sealing sealing peel peel strength strengthof ofmore more than than 10 10 N/15 mmwas N/15 mm was deterioratedininease deteriorated easeofof opening. The opening. The packaging packaging bagsbags obtained obtained fromfrom the heat-sealable the heat-sealable paper paper of Comparative of Comparative

Examples4 4toto66each Examples eachhaving havinga alongitudinal longitudinaland andtransverse transversegeometric geometricmean mean of of a tearindex a tear indexofof 2 were deteriorated in drop impact resistance and were torn. less than less than 10 10 mNm mN.m²/g/g were deteriorated in drop impact resistance and were torn. Theheat-sealable The heat-sealable paper paper of of Examples Examples1 1toto66and and8 8toto13, 13, which whichcontained containeda alubricant, lubricant, were excellent were excellent in in blocking resistance. InInaddition, blocking resistance. addition, comparison comparisonbetween between Example Example 2 2 and and Example6 6found Example foundthat thatsuper supercalendering calenderingdecreases decreasesClark Clark stiffnessand stiffness andimproves improves heatsealing heat sealing peel strength. peel strength.

[0126]

It can be said from the above results that the heat-sealable paper of the present It can be said from the above results that the heat-sealable paper of the present

embodiment makes it possible to obtain a packaging bag that is difficult to tear and can be embodiment makes it possible to obtain a packaging bag that is difficult to tear and can be

easily opened at the time of opening. easily opened at the time of opening.

Claims

38 --

CLAIMS CLAIMS

[Claim 1]

[Claim 1]

Heat-sealable paper comprising Heat-sealable paper comprisingone oneorormore more heat-sealablelayers heat-sealable layersononatatleast least one one

surface ofaapaper surface of papersubstrate, substrate, wherein wherein

the heat-sealable layer comprises a water-dispersible resin binder, the heat-sealable layer comprises a water-dispersible resin binder,

aa longitudinal and longitudinal and transverse transverse geometric geometric mean mean of ofindex a tear a tearofindex of the heat-sealable the heat-sealable paper paper 2025238122

2 or more, is 10 is 10 mNm mN.m²/g/g or more, aa burst indexofofthe burst index theheat-sealable heat-sealable paper paper is kPa.m²/g is 3.0 3.0 kPamor 2more, /g or and more, and whentwo when twosuch suchheat-sealable heat-sealablelayers layersare areheat-sealed heat-sealed to to each each other other at at 150C and0.2 150°C and 0.2 MPa MPa for one for one second, second, a a heat heat sealing sealing peel peelstrength strengthisis 2.02.0 N/15 N/15mm mm or or more and 10 more and 10N/15 N/15mmmm or or less. less.
[Claim 2]

[Claim 2]

The heat-sealable paper according to claim 1, wherein the heat-sealable layer further The heat-sealable paper according to claim 1, wherein the heat-sealable layer further

comprises a lubricant. comprises a lubricant.
[Claim 3]

[Claim 3]

The heat-sealable paper according to claim 2, wherein the lubricant comprises at least The heat-sealable paper according to claim 2, wherein the lubricant comprises at least

one selected from one selected the group from the group consisting consisting of of paraffin paraffin wax, wax, carnauba wax,and carnauba wax, andpolyolefin polyolefinwax. wax.
[Claim 4]

[Claim 4]

The heat-sealable paper according to claim 2 or 3, wherein a content of the lubricant in The heat-sealable paper according to claim 2 or 3, wherein a content of the lubricant in

the heat-sealable the heat-sealable layer layerisis1% 1% by by mass mass or or more and5% more and 5%bybymass mass or or less. less.
[Claim 5]

[Claim 5]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 4, 4, wherein wherein aa glass glass transition temperature of the water-dispersible resin binder is 0C or more and 100C or less. transition temperature of the water-dispersible resin binder is 0°C or more and 100°C or less.
[Claim 6]

[Claim 6]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 5, 5, wherein the water- wherein the water- dispersible resin binder comprises at least one selected from the group consisting of a styrene- dispersible resin binder comprises at least one selected from the group consisting of a styrene-

butadiene copolymer butadiene copolymerand and anan olefin-unsaturatedcarboxylic olefin-unsaturated carboxylic acidcopolymer. acid copolymer.
[Claim 7]

[Claim 7]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims22to to 6, 6, wherein the water- wherein the water- dispersible resin dispersible resinbinder bindercomprises comprises a a styrene-butadiene styrene-butadiene copolymer, andthe copolymer, and thelubricant lubricant comprises comprises paraffin wax. paraffin wax.
[Claim 8]

[Claim 8]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims22to to 6, 6, wherein the water- wherein the water- dispersible resin dispersible resinbinder bindercomprises comprises an an olefin-unsaturated olefin-unsaturated carboxylic carboxylic acid acid copolymer, andthe copolymer, and the lubricant comprises lubricant carnaubawax. comprises carnauba wax.

- 39 --
[Claim 9]

[Claim 9]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 8, 8, wherein Canadian wherein Canadian

standard freeness of standard freeness of pulp pulp constituting constituting the thepaper papersubstrate substrateisis 500 mL 500 mL or ormore more and and 750 mLoror 750 mL

less. less.
[Claim 10]

[Claim 10]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 9, 9, wherein wherein aa main main component component ofofpulp pulpconstituting constitutingthe thepaper papersubstrate substrate is is needle needle unbleached kraft pulp. unbleached kraft pulp. 2025238122
[Claim 11]

[Claim 11]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 10, 10, wherein wherein aa value value (Clark (Clark stiffness/basis stiffness/basisweight) weight)obtained obtained by by dividing dividing aalongitudinal longitudinaland andtransverse transversegeometric geometric mean of mean of

Clark stiffness of the heat-sealable paper by a basis weight (g/m²) of the2 heat-sealable paper is Clark stiffness of the heat-sealable paper by a basis weight (g/m ) of the heat-sealable paper is 0.20 m2/g or 0.20 m²/g or more moreand and1.20 m2/gororless. 1.20m²/g less.
[Claim 12]

[Claim 12]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 11, 11, wherein wherein aa piercing piercing strength ofthe strength of theheat-sealable heat-sealable paper paper is 10.0 is 10.0 N or N or more. more.
[Claim 13]

[Claim 13]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 12, 12, wherein wherein aa basis basis weight weight of the paper substrate is 50 g/m² or2 more and 150 g/m² or less. of the paper substrate is 50 g/m or more and 150 g/m or less. 2
[Claim 14]

[Claim 14]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 13, 13, wherein wherein aa basis basis weight weight of the heat-sealable layer is 3 g/m² or2 more and 30 g/m² or less. of the heat-sealable layer is 3 g/m or more and 30 g/m or less. 2
[Claim 15]

[Claim 15]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 14, 14, wherein wherein aa basis basis weight weight of the heat-sealable paper is 50 g/m² or 2more and 200 g/m² or less.2 of the heat-sealable paper is 50 g/m or more and 200 g/m or less.
[Claim 16]

[Claim 16]

Theheat-sealable The heat-sealable paper paper according accordingtoto any anyone oneofofclaims claims11to to 15, 15, wherein the paper wherein the paper substrate is extensible substrate is extensiblepaper. paper.
[Claim 17]

[Claim 17]

A packaging A packagingbag bagusing usingthe theheat-sealable heat-sealablepaper paperaccording accordingtotoany anyone oneofofclaims claims1 1toto16. 16.