AU2021202320A1 - Resin composition and method for producing the same - Google Patents

Abstract

Provided is a resin composition that is superior in stretchability and exhibits superior impact strength even when exposed to low temperature and low humidity for a long time. A resin composition comprising 6 to 45 parts by mass of a modified starch (A), 1 to 5 parts by mass of a water soluble polymer (B), 1 to 50 parts by mass of a polyol plasticizer (C), and 5 to 80 parts by mass of a thermoplastic resin (D), wherein the following formula (1): 0 < mass of (A)/mass of (C) < 1 (1) is satisfied and the total content of the (A), (B), (C) and (D) is 100 parts by mass. 1/2 2 4 3 5 L2 rE2LI L2 L 2L L3 (XI) L2Z~_______ LI' (XI) L2 (XX2) Figure. 1

Description

1/2

2 4 3 5

L2 rE2LI L2

L 2L L3 (XI) L2Z~_______ LI' (XI) L2

(XX2)

Figure. 1

RESIN COMPOSITIONAND METHOD FOR PRODUCING THE SAME TECHNICAL FIELD

[0001]

The present invention relates to a resin composition to be used for a

food packaging container, etc. and a method for producing the same, a film

or sheet comprising the resin composition, a laminate comprising a layer

comprising the resin composition and a method for producing the same, and

a container comprising the laminate.

BACKGROUND ART

[0002]

Heretofore, resin compositions comprising modified starch and

water-soluble polymer have been widely used for containers for packaging

foods because such resin compositions are superior in biodegradability (for

example, JP-A-2013-216918).

PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003]

Patent Document 1: JP-A-2013-216918

SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004]

Resin compositions to be used for such food packaging containers are

required to have, in addition to biodegradability, durability under hostile

conditions and stretchability from the viewpoint of thermoformability.

However, according to the study of the present inventor, conventional resin

compositions may have a reduced impact strength when exposed to low

temperature and low humidity, which are believed to be disadvantageous for

modified starch, for a long period of time, and even if the impact strength is

ensured, the stretchability is lowered. Therefore, it has been found that

the stretchability and the impact strength under low temperature and low

humidity cannot be achieved at the same time.

[0005]

Thus, an object of the present invention is to provide a resin

composition having good stretchability and having good impact strength

even when exposed to low temperature and low humidity for a long time, a

method for producing the same, a film or sheet comprising the resin

composition, a laminate comprising a layer comprising the resin composition,

a method for producing the same, and a container comprising the laminate.

MEANS FOR SOLVING PROBLEMS

[0006]

As a result of diligent studies for solving the above-described

problems, the present inventor has found that the problems can be solved

when a resin composition comprises a modified starch (A), a water-soluble

polymer (B), a polyol plasticizer (C), and a thermoplastic resin (D) in

amounts of 6 to 45 parts by mass, 1 to 5 parts by mass, 1 to 50 parts by

mass, and 5 to 80 parts by mass, respectively, and the mass of the polyol

plasticizer (C) is greater than the mass of the starch (A), and thus has

accomplished the present invention. That is, the present invention

includes the following embodiments.

[0007]

[1] A resin composition comprising:

6 to 45 parts by mass of a modified starch (A);

1 to 5 parts by mass of a water-soluble polymer (B);

1 to 50 parts by mass of a polyol plasticizer (C); and

5 to 80 parts by mass of a thermoplastic resin (D) different from the

water-soluble polymer (B),

wherein the following formula (1) is satisfied,

0 < mass of(A)/mass of (C) < 1 (1)

and the total content of the (A), (B), (C) and (D) is 100 parts by mass.

[2] The resin composition according to [1], wherein the total content

of the modified starch (A), the water-soluble polymer (B), the polyol

plasticizer (C) and the thermoplastic resin (D) is 80% by mass or more with

respect to the mass of the resin composition.

[3] The resin composition according to [1] or [2], wherein the

modified starch (A) has an average amylose content of 45% by mass or more.

[4] The resin composition according to any one of [1] through [31,

wherein the water-soluble polymer (B) is a polyvinyl alcohol-based resin.

[5] The resin composition according to any one of [1] through [4],

wherein the polyol plasticizer (C) comprises at least one selected from the

group consisting of sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol,

lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, and

glycerol.

[61 The resin composition according to any one of [1] through [51,

wherein the thermoplastic resin (D) comprises at least one selected from a

polyolefin-based resin and a polyester-based resin.

[7] The resin composition according to any one of [1] through [6], wherein the thermoplastic resin (D) comprises a biodegradable thermoplastic resin having biodegradability in a biodegradability test in accordance with EN13432.

[8] A film or sheet comprising the resin composition according to any

one of [1] through [7].

[9] A laminate comprising:

an Li layer comprising the resin composition according to any one of

[1] to [7]; and

an L2 layer being different from the L layer and comprising 50% by

mass or more of the same thermoplastic resin (D) as that of the Li layer

and/or an L3 layer comprising 50% by mass or more of a modified starch.

[10] The laminate according to [9], wherein the laminate comprises,

at least a part thereof, a layer configuration selected from the group

consisting of:

a layer configuration having L3 layer/L1 layer/L3 layer in this order,

a layer configuration having L2 layer/L1 layer/L3 layer in this order,

and

a layer configuration having L2 layer/L1 layer/L2 layer in this order.

[11] The laminate according to [9] or [10], wherein at least one Li

layer has a thickness of 10 to 450 pm, at least one L2 layer has a thickness

of 5 to 500 im, and at least one L3 layer has a thickness of 20 to 800 im.

[12] The laminate according to any one of [9] through [11], wherein

the total thickness of the Li layer is 10 to 1000 jim, the total thickness of

the L2 layer is 5 to 1000 jim, and the total thickness of the L3 layer is 20 to

2000 im.

[13] A method for producing the resin composition according to any one of [1] through [7], which comprises a step of mixing a material (X1) comprising a modified starch (A), a water-soluble polymer (B), and optionally a polyol plasticizer (C) and/or a thermoplastic resin (D), and a material (X2) comprising a polyol plasticizer (C) and/or a thermoplastic resin (D).

[14] The method according to [13], wherein in the step, the material

(X1) comprises at least the modified starch (A), the water-soluble polymer

(B) and the thermoplastic resin (D), and the material (X2) comprises at least

the polyol plasticizer (C).

[15] The method according to [13] or [14], wherein the step is a step

of melt-kneading the material (X1) that is a laminate and the material (X2).

[16] The method according to [15], wherein the laminate is the

laminate according to any one of [9] through [12].

[17] The method for producing the laminate according to any one of

[9] through [12], which comprises a step of co-extruding the Li layer and

another layer comprising the L2 layer and/or the L3 layer.

[18] A container comprising the laminate according to any one of [9]

through [12].

EFFECTS OF THE INVENTION

[0008]

The resin composition of the present invention is superior in

stretchability and can have good impact strength even when exposed to low

temperature and low humidity for a long time. For these reasons, it can be

suitably used as a material for a packaging, a container, etc. for foods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]

FIG. 1 is a schematic diagram illustrating a scheme of recycling a

laminate according to one embodiment of the present invention.

FIG. 2 is a schematic view of the twin screw extruder used in

Examples.

EMBODIMENTS OF THE INVENTION

[0010]

[Resin Composition]

The resin composition of the present invention comprises

6 to 45 parts by mass of a modified starch (A), 1 to 5 parts by mass of

a water-soluble polymer (B), 1 to 50 parts by mass of a polyol plasticizer (C),

and 5 to 80 parts by mass of a thermoplastic resin (D) different from the

water-soluble polymer (B),

wherein the following formula (1) is satisfied,

0 < mass of (A)/mass of (C) < 1 (1). The total content of the (A),

(B), (C) and (D) is 100 parts by mass.

[0011]

The present inventor has found that when a resin composition

comprises the modified starch (A), the water-soluble polymer (B), the polyol

plasticizer (C) and the thermoplastic resin (D) in the above proportions,

their compatibility is unexpectedly enhanced, and as a result, the

stretchability of the resin composition is improved and also the impact

strength at low temperature and low humidity is improved. Furthermore,

the present inventor has found that the resin composition of the present

invention is also good in the adhesive strength between layers of a laminate

comprising the resin composition and the recyclability of the resin

composition. In the present specification, stretchability of a resin composition, impact strength at low temperature and low humidity, and recyclability of a resin composition may be simply referred to as stretchability, impact strength, and recyclability, and adhesive strength between layers of a resulting laminate may be simply referred to as adhesive strength. In addition, a modified starch (A) may be referred to component (A) or simply (A), a water-soluble polymer (B) may be referred to as component (B) or simply (B), a polyol plasticizer (C) may be referred to as component (C) or simply (C), and a thermoplastic resin (D) may be referred to as component (D) or simply (D).

[0012]

<Modified Starch (A)>

The modified starch (A) is preferably at least one selected from the

group consisting of an etherified starch, an esterified starch, a cationized

starch, and a crosslinked starch.

[0013]

Examples of the starch include starches derived from cassava, corn,

potato, sweet potato, sago, tapioca, sorghum, bean, bracken, lotus, trapa

japonica, wheat, rice, oat, arrowroot, and pea. Inter alia, starch derived

from corn or cassava is preferable, and starch derived from high amylose

corn is further preferable. Starch may be used singly, or two or more kinds

of starch may be used in combination.

[0014]

Examples of the etherified starch include: alkyl etherified starches,

such as methyl etherified starch; carboxyalkyl etherified starches, such as

carboxymethyl etherified starch; and hydroxyalkyl etherified starches, such

as etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms.

Alternatively, allyl etherified starches and the like can also be used.

[0015]

Examples of the esterified starch include: esterified starches having

a structural unit derived from carboxylic acid, such as esterified starch

having a structural unit derived from acetic acid; esterified starches having

a structural unit derived from a dicarboxylic anhydride, such as esterified

starch having a structural unit derived from maleic anhydride, esterified

starch having a structural unit derived from phthalic anhydride, and

esterified starch having a structural unit derived from octenylsuccinic

anhydride; and esterified starches having a structural unit derived from oxo

acid, such as nitric acid esterified starch, phosphoric acid esterified starch,

and urea-phosphoric acid esterified starch. Other examples thereof include

xanthogenic acid esterified starch and acetoacetic acid esterified starch.

[0016]

Examples of the cationized starch include a reaction product of

starch and 2-diethylaminoethyl chloride and a reaction product of starch

and 2,3-epoxypropyltrimethylammonium chloride.

[0017]

Examples of the crosslinked starch include formaldehyde

crosslinked starch, epichlorohydrin-crosslinked starch, phosphoric acid

crosslinked starch, and acrolein-crosslinked starch.

[0018]

From the viewpoint of being likely to enhance the stretchability, the

impact strength, the adhesive strength, and the recyclability, the modified

starch (A) is preferably at least one selected from the group consisting of an

etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms and an esterified starch having a structural unit derived from a dicarboxylic anhydride, and is more preferably at least one selected from the group consisting of hydroxyethyl etherified starch, hydroxypropyl etherified starch, hydroxybutyl etherified starch, an esterified starch having a structural unit derived from maleic anhydride, an esterified starch having a structural unit derived from phthalic anhydride, and an esterified starch having a structural unit derived from octenylsuccinic anhydride. The modified starch (A) may be used singly, or two or more species thereof may be used in combination. In the present specification, the number of carbon atoms prefixed to "starch" indicates the number of carbon atoms of a group that has substituted for one hydroxyl group in the starch (a group formed by modifying one hydroxyl group in the starch). For example, an etherified starch having a hydroxyalkyl group having 2 to 5 carbon atoms indicates that the number of carbon atoms of the hydroxyalkyl group formed by modifying one hydroxyl group in the starch is 2 to 5.

[0019]

The etherified starch having a hydroxyalkyl group having 2 to 6

carbon atoms may be an etherified starch obtained by a reaction between

alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide,

and starch. The average number of hydroxy groups to be used in

modification is preferably 0.05 to 2 per one glucose unit in the starch.

[0020]

In the modified starch (A), the average amylose content of the

modified starch (A) is preferably 45% by mass or more, more preferably 50%

by mass or more, and even more preferably 55% by mass or more. When

the average amylose content is equal to or greater than the aforementioned lower limit, it is easy to enhance the stretchability, the impact strength, the adhesive strength, the recyclability, and the biodegradability. The average amylose content in the modified starch (A) is usually 90% by mass or less.

In the present specification, the amylose content can be measured by, for

example, the colorimetric iodine method described in "Starch Vol. 50, No. 4,

158-163 (1998)." When the modified starch contains only a single kind of

modified starch, the average amylose content means the amylose content of

the single modified starch. When two or more modified starches are used,

the average amylose content is determined by weighted averaging the

amylose contents of the two or more modified starches. For this reason, for

example, when two or more modified starches are used and the average

amylose content is adjusted to 45% by mass or more, a modified starch with

an amylose content of less than 45% by mass may be contained.

[0021]

In the modified starch (A), the water content in the modified starch

(A) may be preferably 5 to 15% by mass.

[0022]

As the modified starch (A), a commercially available modified starch

may be used. Examples of a representative commercial product of the

modified starch (A) include ECOFILM (trademark) and National 1658

(trademark), which are hydroxypropyl etherified starches manufactured by

Ingredion Incorporated.

[0023]

The content of the modified starch (A) is 6 to 45 parts by mass per

100 parts by mass in total of the components (A), (B), (C) and (D). If the

content of the modified starch (A) is less than 6 parts by mass or more than

45 parts by mass, the stretchability, the impact strength, the adhesive

strength, and the recyclability tend to lower.

The content of the modified starch (A) is 6 parts by mass or more,

preferably 7 parts by mass or more, more preferably 8 parts by mass or

more, and even more preferably 9 parts by mas or more, whereas it is 45

parts by mass or less, preferably 40 parts by mass or less, more preferably

35 parts by mass or less, even more preferably 30 parts by mass or less,

further preferably 25 parts by mass or less, and particularly preferably 20

parts by mass or less. When the content of the modified starch (A) is in the

above range, it is easy to enhance the stretchability, the impact strength,

the adhesive strength, and the recyclability.

[0024]

<Water-Soluble Polymer (B)>

The water-soluble polymer (B) is not particularly limited as long as

it is a water-soluble polymer, but it is preferably a polyvinyl alcohol-based

resin. Examples of the polyvinyl alcohol-based resin include: ethylene

vinyl alcohol copolymers, polyvinyl alcohol, and polyvinyl acetal; among

these, polyvinyl alcohol is preferable from the viewpoint of easily improving

the stretchability.

[0025]

The polyvinyl alcohol preferably has a degree of saponification of 80

to 99.8 mol%. When the degree of saponification of the polyvinyl alcohol

(B) is in the above range, it is easy to enhance the stretchability, the impact

strength, the adhesive strength, and the recyclability. The degree of

saponification is more preferably 85 mol% or more, even more preferably 90

mol% or more, further preferably 95 mol% or more, and still further preferably 98 mol% or more. In the present specification, the degree of saponification refers to the molar fraction of hydroxyl groups to the total of hydroxyl groups and ester groups in the polyvinyl alcohol.

[0026]

The polyvinyl alcohol can further comprise another monomer unit

other than a vinyl alcohol unit. Examples of the other monomer unit

include monomer units derived from ethylenically unsaturated monomers.

Examples of the ethylenically unsaturated monomers include: a-olefins such

as ethylene, propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and

salts thereof; unsaturated monomers having an acrylic acid ester group;

methacrylic acid and salts thereof; unsaturated monomers having a

methacrylic acid ester group; acrylamide, N-methylacrylamide, N

ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide,

acrylamidopropanesulfonic acid and salts thereof,

acrylamidopropyldimethylamine and salts thereof (e.g., quaternary salts);

methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide,

methacrylamidopropanesulfonic acid and salts thereof,

methacrylamidopropyldimethylamine and salts thereof (e.g., quaternary

salts); vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl

vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t

butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether, and 2,3-diacetoxy

1-vinyloxypropane; vinyl cyanides such as acrylonitrile and

methacrylonitrile; halogenated vinyls such as vinyl chloride and vinyl

fluoride; halogenated vinylidenes such as vinylidene chloride and vinylidene

fluoride; allyl compounds such as allyl acetate, 2,3-diacetoxy-1

allyloxypropane, and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid, and salts or esters thereof; vinylsilyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl calrylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, and vinyl benzoate. The content of the other monomer unit is preferably 10 mol% or less, and more preferably 5 mol% or less.

[0027]

The method for producing the polyvinyl alcohol is not particularly

limited. Examples thereof include a method comprising polymerizing a

vinyl alcohol monomer optionally with another monomer, and saponifying

the resulting polymer to convert into a vinyl alcohol unit. Examples of a

polymerization manner used in polymerization include batch polymerization,

semi-batch polymerization, continuous polymerization, and semi-continuous

polymerization. Examples of the polymerization method include known

methods such as a mass polymerization method, a solution polymerization

method, a suspension polymerization method, and an emulsion

polymerization method. As the saponification of the polymer, a known

method can be applied. For example, the saponification may be performed

in a state where the polymer is dissolved in an alcohol or a hydrous alcohol.

The alcohol that can be used at that time is a lower alcohol such as

methanol and ethanol.

[0028]

The viscosity at 20°C of a 4% aqueous solution of the water-soluble

polymer (B) as measured in accordance with JIS Z 8803 is preferably 1

mPa-s or more, more preferably 2 mPa-s or more, and even more preferably

3 mPa-s or more, whereas it is preferably 45 mPa-s or less, and more

preferably 35 mPa-s or less. When the viscosity of the water-soluble

polymer (B) is in the above range, it is easy to improve the stretchability, the

impact strength, the adhesive strength, and the recyclability. The viscosity

of the water-soluble polymer (B) can be measured using a viscometer and

can be measured, for example, by the method described in Examples.

[0029]

The content of the water-soluble polymer (B) is 1 to 5 parts by mass

per 100 parts by mass in total of the components (A), (B), (C) and (D). If

the content of the water-soluble polymer (B) is less than 1 part by mass or

more than 5 parts by mass, the stretchability and the impact strength tend

to lower.

The content of the water-soluble polymer (B) is 1 part by mass or

more, and preferably 1.2 parts by mass or more, whereas it is 5 parts by

mass or less, preferably 4.5 parts by mass or less, more preferably 4.0 parts

by mass or less, even more preferably 3.5 parts by mass or less, and further

preferably 3.0 parts by mass or less. When the content of the water-soluble

polymer (B) is in the above range, it is easy to improve the stretchability

and the impact strength.

[0030]

<Polyol Plasticizer (C)>

The polyol plasticizer (C) is not particularly limited and examples

thereof include sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol,

lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose,

glycerol, ethylene glycol, and propylene glycol. These polyol plasticizers (C)

may be used singly or two or more of them may be used in combination.

Among these, from the viewpoint of easily enhancing the stretchability, the

impact strength, and the recyclability, at least one selected from the group

consisting of sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol,

arabinose, xylose, fructose, glucose, galactose, ribose, trehalose and glycerol

is preferably contained in the polyol plasticizer (C), and at least one selected

from the group consisting of sorbitol, xylitol and sucrose is more preferably

contained. As the polyol plasticizer, for example, a commercially available

product may be used.

[0031]

The content of the polyol plasticizer (C) is 1 to 50 parts by mass per

100 parts by mass in total of the components (A), (B), (C) and (D). If the

content of the polyol plasticizer (C) is less than 1 part by mass or more than

50 parts by mass, the stretchability, the impact strength, and the

recyclability tend to lower.

The content of the polyol plasticizer (C) is 1 part by mass or more,

preferably 5 parts by mass or more, more preferably 10 parts by mass or

more, and even more preferably 15 parts by mas or more, whereas it is 50

parts by mass or less, preferably 45 parts by mass or less, more preferably

40 parts by mass or less, even more preferably 35 parts by mass or less, and

particularly preferably 30 parts by mass or less. When the content of the

polyol plasticizer (C) is in the above range, it is easy to improve the

stretchability, the impact strength, and the recyclability.

[0032]

<Thermoplastic Resin (D)>

The thermoplastic resin (D) is not particularly limited, and examples

thereof include a polyester-based resin, an olefin-based resin, a polyvinyl based resin, a polyacrylic resin, a polycarbonate-based resin, a polythiocarbonate-based resin, a polyacetal-based resin, a polyamide-based resin, a polyphenylene ether-based resin, a polysulfone-based resin, a polyphenylene sulfide-based resin, a polyimide-based resin, a polyether ketone-based resin, and a thermoplastic elastomer. These thermoplastic resins (D) may be used singly or two or more species thereof may be used in combination. Among these, from the viewpoint of easily enhancing the stretchability, the impact strength, the adhesive strength, and the recyclability, the thermoplastic resin (D) preferably comprises at least one selected from the polyolefin-based resin and the polyester-based resin.

Further, in one embodiment of the present invention, the thermoplastic

resin (D) is preferably a water-insoluble resin.

[0033]

Examples of the polyolefin-based resin include chain polyolefin

based resins such as polyethylene, polypropylene, and polymethylpentene,

and cyclic polyolefin-based resins such as cyclopentadiene and norbornene.

Among these, a chain polyolefin-based resin is preferable from the viewpoint

of easily enhancing the stretchability, the impact strength, the adhesive

strength, and the recyclability, and polyethylene (for example, low density

polyethylene), polypropylene, and the like are more preferable. The

polyolefin-based resin may be used singly or two or more species thereof

may be used in combination.

[0034]

Polyethylene refers to any polymer whose main component is a

constitutional unit derived from ethylene, and polypropylene refers to any

polymer whose main component is a constitutional unit derived from propylene. Polyethylene and polypropylene each can further contain constitutional units other than the above-mentioned constitutional units.

Examples of such other constitutional units include the above-mentioned

ethylenically unsaturated monomers other than ethylene or propylene.

The content of the other monomer unit is preferably 10 mol% or less, and

more preferably 5 mol% or less. As the polyethylene or polypropylene, for

example, commercially available products may be used.

[0035]

The polyester-based resin refers to any polymer having an ester

linkage as a main linkage in the main chain, and refers to, for example, a

polymer having a constitutional unit derived from a dicarboxylic acid and a

constitutional unit derived from a diol, or a polymer having a constitutional

unit derived from a hydroxycarboxylic acid. When a polyester-based resin

is used as the thermoplastic resin (D), the resin composition of the present

invention tends to enhance the stretchability, the impact strength, the

adhesive strength and the biodegradability, and is superior especially in

biodegradability and adhesive strength.

In the present specification, the "constitutional unit derived from"

may be simply referred to as "unit"; for example, a constitutional unit

derived from a dicarboxylic acid is referred to as a dicarboxylic acid unit, a

constitutional unit derived from a diol is referred to as a diol unit, and a

constitutional unit derived from a hydroxycarboxylic acid is referred to as a

hydroxycarboxylic acid unit.

[0036]

When the thermoplastic resin (D) is a polyester-based resin,

examples of the dicarboxylic acid constituting the dicarboxylic acid unit include: aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, norbornenedicarboxylic acid, and tricyclodecanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, biphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, sodium sulfoisophthalate., 2,6 naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 2,7 naphthalenedicarboxylic acid; and ester-forming derivatives thereof.

Among these, the aliphatic dicarboxylic acid or the aromatic dicarboxylic

acid is preferable, the aromatic dicarboxylic acid is more preferable, and

terephthalic acid is further preferable, from the viewpoint of easily

enhancing the adhesive strength and the recyclability. Such a dicarboxylic

acid may be used singly or two or more of them may be used in combination.

When the polyester-based resin contains the aromatic dicarboxylic acid unit,

the content of the aromatic dicarboxylic acid unit is preferably 50 mol% or

more, more preferably 70 mol% or more, even more preferably 90 mol% or

more, and particularly preferably 95 mol% or more, with respect to the total

molar amount of all constitutional units derived from a dicarboxylic acid.

[0037]

When the thermoplastic resin (D) is a polyester-based resin,

examples of the diol constituting the diol unit include: aliphatic diols such

as ethylene glycol, trimethylene glycol, butylene glycol (tetramethylene

glycol), hexamethylene glycol, neopentyl glycol, methylpentane diol, and

diethylene glycol; alicyclic diols such as cyclohexanedimethanols (e.g., 1,2

cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4 cyclohexanedimethanol), norbornenedimethanol, and tricyclodecanedimethanol; and aromatic diols such as bisphenol-based compounds and hydroquinone-based compounds. Among these, the aliphatic diol is preferable, ethylene glycol, trimethylene glycol and butylene glycol are more preferable, and butylene glycol is further preferable, from the viewpoint of easily enhancing the adhesive strength and the recyclability.

Such a diol may be used singly or two or more of them may be used in

combination. When the polyester-based resin contains a diol unit, the

content of the aliphatic diol unit is preferably 50 mol% or more, more

preferably 70 mol% or more, even more preferably 90 mol%, and particularly

preferably 95 mol% or more, with respect to the total molar amount of all

the constitutional units derived from a diol.

[0038]

In one embodiment of the present invention, when the polyester

based resin contains the dicarboxylic acid unit and the diol unit, the ratio of

the dicarboxylic acid unit to the diol unit is preferably 10:1 to 1:10, more

preferably 5:1 to 1:5, even more preferably 2:1 to 1:2, and particularly

preferably 1:1.

[0039]

When the thermoplastic resin (D) is a polyester-based resin,

examples of the hydroxycarboxylic acid constituting the hydroxycarboxylic

acid unit include: aliphatic hydroxycarboxylic acids such as 10

hydroxyoctadecanoic acid, lactic acid, hydroxyacrylic acid, 2-hydroxy-2

methylpropionic acid, and hydroxybutyric acid; alicyclic hydroxycarboxylic

acids such as hydroxymethylcyclohexanecarboxylic acid,

hydroxymethylnorbornenecarboxylic acid, and hydroxymethyltricyclodecanecarboxylic acid; aromatic hydroxycarboxylic acids such as hydroxybenzoic acid, hydroxytoluic acid, hydroxynaphthoeic acid, 3-(hydroxyphenyl)propionic acid, hydroxyphenylacetic acid, and 3 hydroxy-3-phenylpropionic acid; and ester-forming derivatives thereof.

Among these, the aliphatic hydroxycarboxylic acid is preferable, lactic acid

and hydroxybutyric acid are more preferable, and lactic acid is further

preferable, from the viewpoint of easily enhancing the adhesive strength

and the recyclability. Such a hydroxycarboxylic acid may be used singly or

two or more of them may be used in combination.

[0040]

The polyester-based resin may have the dicarboxylic acid unit and

the diol unit, may have the hydroxycarboxylic acid unit, or may have these

constitutional units in combination. Further, the polyester-based resin

may contain constitutional units other than the dicarboxylic acid unit, the

diol unit and the hydroxycarboxylic acid unit as long as the effect of the

present invention is not impaired.

[0041]

In one embodiment of the present invention, the polyester-based

resin may be a copolymer of butylene adipate and butylene terephthalate

[PBAT, poly(butylene adipate-co-butylene terephthalate)], a copolymer of

butylene succinate and butylene adipate [PBSA, poly(butylene succinate-co

butylene adipate)], polylactic acid (PLA), polybutylene succinate,

polyhydroxybutyrate (PHB), polyethylene terephthalate copolymer (PETG),

or a mixture thereof, and from the viewpoint of easily enhancing the

adhesive strength and the recyclability, PBAT, PLA, PETG, or a mixture

thereof is preferable, and PBAT, PLA, or a mixture thereof is more preferable.

[0042]

In one embodiment of the present invention, the thermoplastic resin

(D) preferably comprises a biodegradable thermoplastic resin having

biodegradability and a biodegradable polyester-based resin in a

biodegradability test in accordance with EN13432. By comprising such

thermoplastic resins, the biodegradability can be enhanced. When the

thermoplastic resin (D) comprises a biodegradable thermoplastic resin, the

content of the biodegradable thermoplastic resin is preferably 30% by mass

or more, more preferably 50% by mass or more, even more preferably 70%

by mass or more, and particularly preferably 90% by mass or more, with

respect to the mass of the thermoplastic resin (D), from the viewpoint of

easily enhancing the biodegradability.

The thermoplastic resin (D) may be produced by a conventional

method, or a commercially available product may be used.

[0043]

In one embodiment of the present invention, the melt volume rate

(MVR) of the thermoplastic resin (D) measured at 190°C and 5 kgf is

preferably 0.5 mL/10 minutes or more, more preferably 1.0 mL/10 minutes

or more, and even more preferably 1.5 mL/10 minutes or more, whereas it is

preferably 30 mL/10 minutes or less, more preferably 20 mL/10 minutes or

less, and even more preferably 10 mL/10 minutes or less. When the MVR

of the thermoplastic resin (D) is in the above range, it is easy to enhance the

stretchability, the impact strength, and the recyclability. The MFR and the

MVR of the thermoplastic resin (D) can be adjusted, for example, by

appropriately changing the molecular weight, the type of constitutional units, and the contents thereof.

[0044]

In one embodiment of the present invention, the melt flow rate

(MFR) of the thermoplastic resin (D) measured at 190 to 230°C and 2.16 kgf

is preferably 0.1 g/10 minutes or more, more preferably 0.5 g/10 minutes or

more, and even more preferably 1.0 g/10 minutes or more, whereas it is

preferably 50 g/10 minutes or less, more preferably 30 g/10 minutes or less,

and even more preferably 20 g/10 minutes or less. When the MFR of the

thermoplastic resin (D) is in the above range, it is easy to enhance the

stretchability, the impact strength, and the recyclability. The measurement

temperature under the above MFR conditions is, for example, preferably

190°C when the thermoplastic resin is polyethylene, and preferably 230°C

when the thermoplastic resin is polypropylene.

[0045]

The content of the thermoplastic resin (D) is 5 to 80 parts by mass

per 100 parts by mass in total of the components (A), (B), (C) and (D). If

the content of the thermoplastic resin (D) is less than 5 parts by mass or

more than 80 parts by mass, the stretchability, the impact strength, the

adhesive strength, and the recyclability tend to lower.

The content of the thermoplastic resin (D) is 5 parts by mass or more,

preferably 10 parts by mass or more, more preferably 20 parts by mass or

more, even more preferably 30 parts by mas or more, further preferably 40

parts by mas or more, even further preferably 50 parts by mas or more, and

particularly preferably 55 parts by mas or more, whereas it is 80 parts by

mass or less, preferably 75 parts by mass or less, and more preferably 70

parts by mass or less. When the content of the thermoplastic resin (D) is in the above range, it is easy to improve the stretchability, the impact strength, the adhesive strength, and the recyclability.

[0046]

<Resin Composition>

Since the resin composition of the present invention comprises 6 to

45 parts by mass of a modified starch (A), 1 to 5 parts by mass of a water

soluble polymer (B), 1 to 50 parts by mass of a polyol plasticizer (C), and 5 to

80 parts by mass of a thermoplastic resin (D) per 100 parts by mass in total

of the components (A), (B), (C) and (D), and satisfies the following formula

(1):

0 <mass of (A)/mass of (C) < 1 (1)

both good stretchability and good impact strength at low

temperature and low humidity can be achieved. In addition, a laminate

comprising a layer comprising the resin composition can exhibit good

adhesive strength at the interface with a layer adjacent to that layer.

Further, as described later, the resin composition of the present invention

also has good recyclability. Thus, the resin composition of the present

invention can be suitably used as a material for food packaging and

containers.

[0047]

In the formula (1), when the mass of (A)/the mass of (C) is 0, or 1 or

more, the stretchability, the impact strength, the adhesive strength, and the

recyclability tend to lower.

[0048]

In the formula (1), the mass of(A)/the mass of (C) is preferably 0.1

or more, more preferably 0.2 or more, and even more preferably 0.3 or more, whereas it is preferably 0.95 or less, more preferably 0.90 or less, even more preferably 0.85 or less, and particularly preferably 0.75 or less. When the mass of (A)/the mass of (C) is in the above range, it is easy to enhance the stretchability, the impact strength, the adhesive strength, and the recyclability.

[0049]

The resin composition of the present invention may further comprise

a fatty acid having 12 to 22 carbon atoms and/or a fatty acid salt thereof.

Examples of the fatty acid having 12 to 22 carbon atoms and a fatty acid

salt thereof include stearic acid, calcium stearate, sodium stearate, palmitic

acid, lauric acid, myristic acid, linoleic acid, and behenic acid. Among these,

stearic acid, calcium stearate, and sodium stearate are preferable from the

viewpoint of processability (e.g., stretchability). The fatty acid having 12 to

22 carbon atoms and the fatty acid salt thereof may be used singly or two or

more of them may be used in combination.

[0050]

When the resin composition of the present invention contains a fatty

acid having 12 to 22 carbon atoms and/or a fatty acid salt thereof, the

content thereof in the resin composition is preferably 0.01 to 3% by mass,

more preferably 0.03 to 2% by mass, and even more preferably 0.1 to 1% by

mass, with respect to the mass of the resin composition. When the content

of the fatty acid having 12 to 22 carbon atoms and/or the fatty acid salt

thereof is in the above range, it tends to be advantageous in terms of

processability.

[0051]

The resin composition of the present invention may further comprise clay. Examples of the clay include synthetic or natural layered silicate clays such as montmorillonite, bentonite, beidellite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, ledikite, magadite, kenyaite, stevensite, and volkonskoite. The clay may be used singly or two or more thereof may be used in combination.

[00521

When the resin composition of the present invention contains clay,

the content thereof in the resin composition is preferably 0.1 to 5% by mass,

more preferably 0.1 to 3% by mass, even more preferably 0.5 to 2% by mass,

with respect to the mass of the resin composition. When the clay content is

in the above range, it tends to be advantageous in terms of transparency

and strength.

[0053]

The resin composition of the present invention may comprise a

plasticizer (E) other than the polyol plasticizer (C). Examples of the

plasticizer (E) include water, glycerol trioleate, epoxidized linseed oil,

epoxidized soybean oil, tributyl citrate, acetyltriethyl citrate, glyceryl

triacetate, and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate. The

plasticizer (E) may be used singly or two or more of them may be used in

combination. Among these plasticizers (E), water is preferable from the

viewpoint of being able to obtain good film-forming property and coating

property.

[0054]

The water content in the resin composition is preferably 3 to 20% by

mass, more preferably 4 to 18% by mass, and even more preferably 7 to 15%

by mass, with respect to the mass of the resin composition, from the viewpoint of easily enhancing the film-forming property of the resin composition. The water content can be determined, for example, by measuring at 130°C for 60 minutes using a heat-drying moisture meter.

[0055]

The resin composition of the present invention may further comprise

additives such as a filler, a processing stabilizer, a weather resistance

stabilizer, a coloring agent, an ultraviolet absorbing agent, a light stabilizer,

an antioxidant, an antistatic agent, a flame-retardant, an other

thermoplastic resin, a lubricant, a perfume, an antifoaming agent, a

deodorant, a bulking agent, a releasing agent, a mold releasing agent, a

reinforcing agent, a crosslinking agent, a fungicide, an antiseptic, and a

crystallization rate retardant, as necessary.

[0056]

In the resin composition of the present invention, the total content of

the modified starch (A), the water-soluble polymer (B), the polyol plasticizer

(C) and the thermoplastic resin (D) is preferably 60% by mass or more, more

preferably 80% by mass or more, even more preferably 85% by mass or more,

and further preferably 90% by mass or more with respect to the mass of the

resin composition, and it is preferably 100% by mass or less. When the

total content of the components (A), (B), (C) and (D) is in the above range, it

is easy to enhance the stretchability, the impact strength, the adhesive

strength, and the recyclability.

[0057]

The resin composition of the present invention may be in the form of

a pellet or a film or sheet, for example. When the resin composition of the

present invention is used as a film or a sheet, the thickness of the film is commonly 5 to 100 im, and the thickness of the sheet is commonly 100 Pm to 1000 pm. Further, the film or sheet may have a single layer or multiple layers. In the present specification, the term "sheet" can be substituted for

"film", and the term "film" can be substituted for "sheet".

[0058]

Since the stretchability of the resin composition of the present

invention increases as the strain at break increases, it can be evaluated by

measuring the strain at break. The strain at break of the resin

composition is preferably 170% or more, more preferably 250% or more,

even more preferably 300% or more, further preferably 400% or more,

particularly preferably 480% or more, and more particularly preferably

600% or more. When the strain at break is equal to or more than the above

lower limit, the resin composition is superior in stretchability. The upper

limit of the strain at break is usually 1500% or less. The strain at break

can be measured using a tensile tester, and can be measured by, for example,

the method described in Examples.

[0059]

The resin composition of the present invention has good impact

strength even when exposed to low temperature and low humidity (for

example, 0°C, humidity 10% RH) for a long time (for example, two weeks).

The impact strength of the film or sheet comprising the resin composition of

the present invention after adjusting the humidity at 0°C and 10% RH for

two weeks is preferably 2.5 mN/im or more, more preferably 3.0 mN/im or

more, even more preferably 4.5 mN/im or more, further preferably 6.0

mN/im or more, and particularly preferably 7.0 mN/im or more. When

the impact strength is equal to or more than the above lower limit, the film or sheet can exhibit good impact strength. The impact strength can be measured using an impact strength tester after adjusting the humidity for two weeks in an environment with a temperature of 0°C and a humidity of

10% RH, and can be measured by, for example, the method described in

Examples.

[0060]

[Laminate]

The present invention includes a laminate comprising an Li layer

comprising the resin composition described above, and an L2 layer being

different from the Li layer and comprising 50% by mass or more of a

thermoplastic resin and/or an L3 layer comprising 50% by mass or more of a

modified starch. In the laminate of the present invention, the Li layer

comprises the resin composition of the present invention, the L2 layer

comprises 50% by mass or more of a thermoplastic resin, and the L3 layer

comprises 50% by mass or more of a modified starch. Hence, when the Li

layer is adjacent to the L2 layer and/or the L3 layer, the laminate is superior

in the adhesive strength at the interface with the L layer. For this reason,

the laminate of the present invention can have sufficient strength without

an adhesive.

[0061]

In the laminate of the present invention, the L2 layer is a layer

different from the Li layer, and is a layer comprising 50% by mass or more

of a thermoplastic resin with respect to the mass of the L2 layer. The

thermoplastic resin may be, for example, the thermoplastic resin (D)

described above, a conventional thermoplastic resin other than the

thermoplastic resin (D), or a combination thereof, and from the viewpoint of easily enhancing the adhesiveness with the Li layer, the thermoplastic resin preferably contains at least the thermoplastic resin (D), more preferably is the thermoplastic resin (D), and even more preferably is the same thermoplastic resin (D) as the Li layer. The layer different from the

Li layer means that the component constituting the L2 layer is not the resin

composition of the present invention.

[0062]

The L2 layer is a layer different from the LI layer, and may contain

other components as long as it contains 50% by mass or more of the

thermoplastic resin. The other components are not particularly limited,

and examples thereof include the additives described above, conventional

resins (for example, a polyolefin-based resin, a polystyrene-based resin, a

polyvinyl chloride, a polyvinylidene chloride, a polyacrylic resin, a

polyurethane-based resin, a polycarbonate-based resin, a polyamide-based

resin, and a polyimide-based resin), the modified starch (A) described above,

the water-soluble polymer (B) described above, the polyol plasticizer (C)

described above, the above-described fatty acid having 12 to 22 carbon

atoms and/or a fatty acid salt thereof, the clay described above, and the

plasticizer (E) described above.

[0063]

The content of the thermoplastic resin contained in the L2 layer is

preferably 60% by mass or more, more preferably 70% by mass or more,

even more preferably 80% by mass or more, and further preferably 90% by

mass or more, whereas it is preferably 100% by mass or less. When the

content of the thermoplastic resin is in the above range, it is easy to enhance

the adhesive strength with the L layer.

[0064]

The L3 layer is a layer comprising 50% by mass or more of a

modified starch. The modified starch may be, for example, the modified

starch (A) described above, a conventional modified starch other than the

modified starch (A), or a combination thereof, and from the viewpoint of

easily enhancing the adhesiveness with the Li layer, it preferably comprises

at least the modified starch (A), and more preferably is the modified starch

(A). The L3 layer may comprise the above-mentioned other components,

and from the viewpoint of easily enhancing the adhesiveness with the Li

layer, it preferably comprises a water-soluble polymer (B). When the L3

layer comprises the water-soluble polymer (B), the content of the water

soluble polymer (B) is preferably 2% by mass or more, more preferably 5%

by mass or more, with respect to the mass of the L3 layer, whereas it is

preferably 40% by mass or less, more preferably 30% by mass or less, and

even more preferably 20% by mass or less.

[0065]

The content of the modified starch contained in the L3 layer is

preferably 60% by mass or more, more preferably 70% by mass or more, and

even more preferably 80% by mass or more, with respect to the mass of the

L3 layer, whereas it is preferably 100% by mass or less, and more preferably

98% by mass or less. When the content of the modified starch is in the

above range, it is easy to enhance the adhesive strength with the Li layer

and the strength of the laminate.

[0066]

The laminate of the present invention may comprise one or more Li

layers, and one or more L2 layer and/or one or more L3 layers, and may comprise two or more layers of any one or all of them. When two or more layers are comprised, the thickness and composition of each layer may be either the same or different.

[0067]

In one embodiment of the present invention, from the viewpoint of

easily enhancing the adhesiveness between layers and the strength of the

laminate, the thickness of at least one L layer is preferably 10 to 450pm,

the thickness of at least one L2 layer is 5 to 500 pm, and the thickness of at

least one L3 layer is preferably 20 to 800pm.

[0068]

The thickness of at least one L layer is more preferably 50 pm or

more, even more preferably 100 pm or more, and particularly preferably 150

pm or more, whereas it is more preferably 450 pm or less, even more

preferably 400 pm or less, and particularly preferably 350 pm or less.

The thickness of at least one L2 layer is more preferably 10 pm or

more, even more preferably 20 pm or more, whereas it is more preferably

500 pm or less, even more preferably 200 pm or less, and particularly

preferably 80 pm or less.

The thickness of at least one L3 layer is more preferably 50 pm or

more, even more preferably 70 pm or more, and particularly preferably 200

pm or more, whereas it is more preferably 800 pm or less, even more

preferably 600 pm or less, and particularly preferably 400 pm or less.

[0069]

In one embodiment of the present invention, from the viewpoint of

easily enhancing the adhesiveness between the layers and the strength of

the laminate, the total thickness of the L layer(s) is preferably 10 to 1000 ym, the total thickness of the L2 layer(s) is preferably 5 to 300 Pm, and the total thickness of the L3 layer(s) is preferably 20 to 2000 pim.

[0070]

The total thickness of the Li layer(s) is more preferably 50 rm or

more, even more preferably 100 pm or more, and particularly preferably 150

pim or more, whereas it is more preferably 800 pm or less, and even more

preferably 700 pm or less.

The total thickness of the L2 layer(s) is more preferably 10 pm or

more, and even more preferably 20 pm or more, whereas it is more

preferably 1000 pm or less, even more preferably 500 pm or less, and

further preferably 200 pm or less.

The total thickness of the L3 layer(s) is more preferably 50 pm or

more, even more preferably 70 pim or more, and particularly preferably 200

pm or more, whereas it is more preferably 1600 pm or less, even more

preferably 1200 pm or less, and particularly preferably 800 pm or less. The

total thickness of layer(s) indicates the thickness of one layer when the

layer(s) is a single layer, and indicates the total thickness of all the layers

when the layer(s) is two or more layers. The thickness of each layer can be

measured using a microscope, and can be measured by, for example, the

method described in Examples.

[0071]

In one embodiment of the present invention, the laminate of the

present invention comprises, in at least a part thereof, a layer configuration

selected from the group consisting of a layer configuration having L3

layer/L1 layer/L3 layer in this order, a layer configuration having L2

layer/L1 layer/L3 layer in this order, and a layer configuration having L2 layer/L1 layer/L2 layer in this order. When such a layer configuration is comprised, good adhesive strength is exhibited at the interface between the

Li layer and the L2 layer and the interface between the Li layer and the L3

layer because the Li layer is adjacent to the L2 layer and/or the L3 layer,

and thus, the strength of the laminate is likely to be improved.

[0072]

In one embodiment of the present invention, the adhesive strength

at the interface between the Li layer and the L2 layer is preferably 25 N/15

mm or more, more preferably 28 N/15 mm or more, and even more

preferably 30 N/15 mm or more. When the adhesive strength is equal to or

greater than the above lower limit, good adhesiveness is likely to be

exhibited. The adhesive strength is usually 100 N/15 mm or less.

The adhesive strength at the interface between the Li layer and the

L3 layer is preferably 15 N/15 mm or more, more preferably 20 N/15 mm or

more, and even more preferably 25 N/15 mm or more. When the adhesive

strength is equal to or greater than the above lower limit, good adhesiveness

is likely to be exhibited. The adhesive strength is usually 100 N/15 mm or

less. The adhesive strength can be measured by adjusting the humidity of

the laminate for two weeks under the condition specified by a temperature

of 23°C and a humidity of 50% RH and then pulling the interface with a

tensile tester, and can be measured by, for example, the method described in

Examples.

[0073]

The laminate of the present invention may comprise a layer (W)

other than the Li layer, the L2 layer and the L3 layer. The layer (W) is not

particularly limited, and examples thereof include a protective layer, a gas barrier layer, a moisture-proof layer, a light-shielding layer, a printing layer, a reinforcing layer, and an adhesive layer. Examples of the material forming such other layer include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, EVOH, polyvinyl chloride, polyurethane, polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyamides such as nylon, polyacrylonitrile, cellulose or derivatives thereof, paper, glass, and wood. As to such other layer, either a single layer or two or more layers may be provided, and it may include either a single layer or multiple layers. When there are two or more such other layers, the thickness and material of each layer may be either different or the same.

[0074]

The laminate of the present invention is not particularly limited,

and examples thereof include laminates having layers in the following

orders:

L2 layer/Li layer/L2 layer; L3 layer/L1 layer/L3 layer; L3 layer/L1

layer/L2 layer; L2 layer/L3 layer/L1 layer/L3 layer/L2 layer; L2 layer/L1

layer/L3 layer/L1 layer/L2 layer.

[0075]

[Method for Producing Resin Composition]

The resin composition of the present invention can be produced by,

for example, a method comprising Step (1) of mixing at least the modified

starch (A), the water-soluble polymer (B), the polyol plasticizer (C) and the

thermoplastic resin (D) to obtain a mixture, Step (2) of extruding the

mixture, and Step (3) of cooling and drying the extruded mixture.

[0076]

Step (1) is a step of mixing at least the modified starch (A), the

water-soluble polymer (B), the polyol plasticizer (C) and the thermoplastic

resin (D), and other components, such as the aforementioned fatty acid

having 12 to 22 carbon atoms and/or a fatty acid salt thereof, the

aforementioned clay, the aforementioned plasticizer (E), and the

aforementioned additive, may optionally be mixed together.

[0077]

Step (1) is usually performed using an extruder. In the extruder, a

shearing stress is applied to each component with a screw, and each

component is uniformly mixed while heating by application of the external

heat to a barrel. Each of the components may be introduced directly into

the extruder, or each of the components may be premixed using a mixer or a

mill and then introduced into the extruder.

[0078]

As the extruder, for example, a twin screw extruder can be used.

The twin screw extruder may be co-rotation or reverse rotation. The screw

diameter may be, for example, 20 to 150 mm, and the ratio L/D ratio of the

extruder length (L) to the screw diameter (D) may be, for example, 20 to 50.

The rotation speed of the screw is preferably 80 rpm or more, and more

preferably 100 rpm or more. The extrusion pressure is preferably 5 bar

(0.5 MPa) or more, and more preferably 10 bar (1.0 MPa) or more.

[0079]

Since the resin composition of the present invention comprises a

polyol plasticizer, it is not necessary to mix a plasticizer (E) other than the

polyol plasticizer in Step (1), but from the viewpoint of the film forming

property, etc. of the resin composition, the plasticizer (E), preferably water, may be mixed. When the plasticizer (E) is mixed, the content of the plasticizer (E) is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 10% by mass or more, further preferably 15 by mas or more, and particularly preferably 20% by mass or more, with respect to the mass of the mixture, whereas it is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. Here, the mass of the mixture is the total mass of the mixture including the plasticizer (E). In Step (1) in the embodiment described above, the plasticizer (E) may be introduced at an initial stage of extrusion, and the plasticizer (E) may be introduced before the temperature reaches the aforementioned heating temperature, for example, at 100°C or lower. The modified starch (A) is subjected to the cooking treatment by the combination of the moisture, the heat, and the shearing stress, and can be gelatinized (gelled). Further, by separately introducing the plasticizer (E), preferably water, a water-soluble polymer such as the water-soluble polymer (B) is dissolved, the resin composition is softened, and the modulus and the brittleness can be reduced.

[0080]

In Step (1), cooking treatment is performed by heating to a

temperature of preferably higher than 100°C and 300°C or lower, and more

preferably 150°C or higher and 250°C or lower. Here, the cooking

treatment is treatment of grinding and gelling starch particles. The

heating can be performed by applying heat to the barrel of the extruder from

the outside. Each barrel can be heated to a target temperature by applying

temperature that is changed stepwise. When the cooking treatment is

performed at a temperature higher than 180°C, this is advantageous in terms of processability.

[0081]

By exhausting the air from the barrel, foaming can be prevented and

the moisture can be removed. The residence time in the extruder can be

set according to the temperature profile and the screw speed, and is

preferably 1 to 2.5 minutes.

[0082]

In Step (2) of extruding the mixture, the molten mixture that has

been pushed in the extruder while being melt-kneaded is extruded through

a die. The temperature of the die is preferably 85 to 3000 C, and more

preferably is 90 to 250C.

[0083]

In Step (3) of cooling and drying the extruded mixture (melt), the

extruded mixture (melt) may be shaped into a film shape or a strand shape,

and then cooled and dried.

[0084]

When the mixture is extruded into a film shape, the mixture can be

extruded through a die for forming a film, and then cooled and dried while

being wound with a winding roller. It is preferable to cool the mixture

between the die and the roller so as to prevent the mixture from adhering to

the roller. A shaping roll may be installed between the die and the roller.

The material of the shaping roll is, for example, rubber, resin, or metal.

For drying, the roll may be warmed or dehumidified air may be supplied

during winding. In the case of the blowing-tube method, the dehumidified

air can be used in order to inflate the film when the film is released from the

die. By accompanying talcin the air stream, blocking of the film can be prevented.

[0085]

When the mixture is extruded into a strand shape, the mixture is

extruded through a multi-hole strand nozzle, and strands are cut with a

rotary cutter, so that the strands can be formed into a pellet shape. In

order to prevent the pellets from agglutinating, the moisture in the pellets

may be removed by applying vibration periodically or regularly and using

hot air, dehumidified air or an infrared heater.

[0086]

(Production by Recycling)

The resin composition of the present invention is superior in

recyclability. In the present specification, recyclability means a property of

being able to form a resin composition of the present invention by reusing a

material (X1) comprising the component (A) and the component (B) as well

as optionally the component (C) and/or the component (D) constituting the

resin composition. In particular, an embodiment in which a layer

comprising the material (X1) or a laminate comprising this layer is reused to

form a resin composition of the present invention is preferable. Here, the

material (X1) has a meaning including not only the case where the

composition of the resin composition of the present invention is satisfied but

also the case where the composition is not satisfied.

[0087]

Since the resin composition of the present invention is superior in

recyclability, it is superior in stretchability, impact strength at low

temperature and low humidity, and adhesive strength in a laminate

obtained therefrom even if the resin composition is formed reusing the material (X). In addition, the resin composition of the present invention can be repeatedly recycled.

[0088]

When the material (X1) is reused to form a resin composition of the

present invention, Step (1) in the method for producing a resin composition

preferably comprises a step of mixing the material (X1) with a material(X2)

comprising a polyol plasticizer (C) and/or a thermoplastic resin (D) (this step

is also referred to as Step (Z)). In the Step (Z), adding the material (X2)

comprising a polyol plasticizer (C) and/or a thermoplastic resin (D),

preferably at least a polyol plasticizer (C), to the material (X), followed by

mixing them, makes it easy to form the resin composition of the present

invention without impairing the effects of the present invention

(stretchability, impact strength, adhesive strength, etc.).

[00891

The form of the material (X1) is not particularly limited, and

examples thereof include a single layer body or a laminate, preferably a

single layer sheet or a multilayer sheet. When the material (X1) is a

laminate, the individual components constituting the material (X1) may be

contained in either the same layer or different layers. For example, when

the material (XI) has a three-layer structure containing the components (A),

(B) and (D), the intermediate layer may comprise the components (A) and

(B) and the outer layers may comprise the component (D).

[0090]

When the material (XI) is a single layer sheet or a multilayer sheet,

it is preferable to pulverize the sheet with a mill before mixing it in an

extruder. The form of the material (X2) may be a sheet shape, but from the viewpoint of production efficiency, it is preferably a form that does not need to be subjected to a mill, such as a pellet shape.

[0091]

Here, when the thermoplastic resin (D) is a water-insoluble

thermoplastic resin, it heretofore is difficult to recycle a material comprising

for example at least a modified starch, a water-soluble polymer and a

thermoplastic resin, especially, a material in the form of a laminate (for

example, a laminate in which an inner layer comprises a modified starch

and a water-soluble polymer and an outer layer comprises a thermoplastic

resin) because a water-soluble polymer and a water-insoluble thermoplastic

resin are poor in compatibility. However, the present inventor has found

that if the composition of the resin composition of the present invention is

modified, the compatibility is unexpectedly improved, so that the resin

composition can be recycled.

[0092]

In the present invention, even if the material (X1) comprises the

thermoplastic resin (D), it can be recycled without impairing the effects of

the present invention. Therefore, in the Step (Z), it is more preferable that

the material (X1) comprises at least a modified starch (A), a water-soluble

polymer (B) and a thermoplastic resin (D) and the material(X2) comprises

at least a polyol plasticizer (C).

[0093]

Further, in the present invention, even if the material (X1) is in the

form of a laminate, which is difficult to mix, it can be recycled without

impairing the effects of the present invention. Therefore, the material (X1)

is preferably a laminate. Although the laminate may be either the laminate of the present invention or a laminate other than the present invention, the laminate of the present invention is preferred from the viewpoint that the laminate of the present invention can be reused.

[0094]

When the material (XI) is a laminate, the Step (Z) is preferably a

step of melt-kneading the material (X1) which is a laminate and the

material (X2), and more preferably a step of melt-kneading the material

(X1) which is a pre-pulverized laminate and the material (X2) using an

extruder as described above.

[0095]

Embodiments of the combination of the material (X1) and the

material (X2) are shown below. In the following embodiments, both the

material (XI) and the material (X2) may comprise components other than

(A), (B), (C) and (D).

(1) Material (X1): (A) (B), Material (X2): (C) (D)

(2) Material (X1): (A) (B) (C), Material (X2): (D)

(3) Material (X1): (A) (B) (C), Material (X2): (C) (D)

(4) Material (Xi): (A) (B) (D), Material (X2): (C)

(5) Material (X1): (A) (B) (D), Material (X2): (C) (D)

(6) Material (X1): (A) (B) (C) (D), Material (X2): (C)

(7) Material (X1): (A) (B) (C) (D), Material (X2): (D)

(8) Material (X1): (A) (B) (C) (D), Material (X2): (C) (D).

[0096]

When the material (X1) is a laminate, the laminate is not

particularly limited, and examples thereof include, in addition to the

laminate of the present invention described in the section [Laminate], a laminate having L2 layer/L3 layer/L2 layer in this order.

[0097]

[Method for Producing Laminate]

The method for producing the laminate of the present invention is

not particularly limited, and may be, for example, a method of performing

co-extrusion; a method of applying a composition extruded from an extruder

onto a layer conveyed by a take-up machine; or a method of combining these

methods.

[0098]

In one embodiment of the present invention, the method for

producing the laminate of the present invention can preferably use a step of

co-extruding the Li layer and other layers comprising the L2 layer and/or

the L3 layer. The other layer may comprise the layer (W) described above.

[0099]

Examples of the extruder to be used for co-extrusion include a single

screw extruder and a twin screw extruder. The screw diameter of the

extruder is, for example, 15 to 150 mm, the ratio L/D ratio of the extruder

length (L) to the screw diameter (D) is, for example, 15 to 50, and the

rotation speed of the screw is preferably 80 rpm or more, and more

preferably 100 rpm or more. The cylinder temperature in the extruder and

the temperature of the die exit may be, for example, 80 to 250°C, and

preferably 90 to 200°C.

[0100]

Further, in one embodiment of the present invention, the method for

producing the laminate of the present invention preferably comprises a step

of co-extrusion and a step of applying the co-extruded composition onto a layer conveyed by a winding machine. When the laminate of the present invention is a laminate having L2 layer/L1 layer/L3 layer/Li layer/L2 layer in this order, for example, the resin composition for forming the Li layers and the composition for forming the L2 layers are fed into an extruder, the resin compositions are plasticized thereby, and then discharged through a die exit for forming a multilayer film. Then, the composition co-extruded through the die exit is applied onto the L3 layer conveyed by the winding machine, preferably a roller type winding machine, so that the Li layer and the L2 layer are laminated on the L3 layer. Further, by coating the opposite surface of the L3 layer in the same manner, a laminate having L2 layer/L1 layer/L3 layer/L1 layer/L2 layer in this order can be obtained. The resulting laminate is conveyed while being pressure-bonded with a pressure roll or the like, and can be wound into a roll by a winding machine. The laminate according to another embodiment of the present invention can be produced by appropriately changing the layer configuration and the composition of the laminate based on a conventional method and the above described embodiment.

[0101]

The Li layer in the laminate of the present invention may be formed

of a non-recycled resin composition or a recycled resin composition.

Further, by recycling the laminate of the present invention as, for example,

a material (Xi), a new resin composition or laminate can be formed.

[0102]

[Recycling]

One embodiment of recycling in the present invention will be

described in more detail.

FIG. 1 is a schematic diagram illustrating a scheme of recycling a

laminate according to one embodiment of the present invention. The

laminate 1 is a laminate other than the present invention, and is a laminate

having L3 layer/L2 layer/L3 layer in this order. When the laminate 1 is

recycled, a resin composition 2 is formed by mixing the material (Xi) which

is the laminate 1 with a material(X2) comprising a polyol plasticizer (C)

and/or a thermoplastic resin (D). Next, the resulting resin composition 2 is

subjected to co-extrusion or the like to form a laminate 3 comprising an Li

layer comprising the resin composition 2. As a result, the Li layer in the

laminate 3 becomes a recycled layer (this is also referred to as a recovery

layer). The layer configuration of the laminate 3 is in the order of L2

layer/Li layer (recovery layer)/L3 layer/Li layer (recovery layer)/L2 layer.

Next, a resin composition 4 is formed by mixing the material (X1) which is

the laminate 3 with a material (X2') comprising a polyol plasticizer (C)

and/or a thermoplastic resin (D). In the same manner as described above,

the resulting resin composition 4 is subjected to co-extrusion or the like to

form a laminate 5 comprising an L' layer (recovery layer) comprising the

resin composition 4. The layer configuration of the laminate 5 is in the

order of L2 layer/Li'layer (recovery layer)/L3 layer/Li'layer (recovery

layer)/L2 layer. As described above, the resin composition or laminate of

the present invention can be repeatedly recycled, and even the recycled

resin composition or laminate can have good stretchability, impact strength,

adhesive strength, etc.

[0103]

For example, when a sheet-shaped laminate 1 is molded into a coffee

capsule container and then used, many thermoformed burrs (for example, about 50%) remain, but in the present invention, such thermoformed burrs

(laminate 1) can be repeatedly recycled as shown in FIG. 1, for example, so

that the environmental load can be reduced. In particular, in the

production of food containers or packaging materials, many scraps such as

thermoformed burrs of the coffee capsule containers are often generated.

Therefore, the resin composition and laminate of the present invention can

be suitably used.

EXAMPLES

[0104]

The present invention is described in detail by way of Examples, but

the present invention is not limited to them.

[0105]

<Test Method>

[0106]

(1) Strain at Break

The stretchability of the resin compositions (single layer sheets)

obtained in Examples and Comparative Examples was evaluated in

accordance with the following method.

The 250 pm single layer sheets obtained in Examples and

Comparative Examples were cut into a strip shape with a width of 15 mm

and a length of 10 cm. Next, each of the cut samples was clipped at both

ends of the short side thereof with chucks of the following tensile tester, and

then stretched at a fixed speed (500 mm/min) and measured until the

sample was broken. Where the distance between the chucks before

stretching is taken as the initial length Ao (mm) and the distance between

the chucks at the time of breakage is taken as the length at break A1 (mm), the strain at break of a single layer sheet is calculated by the following formula.

Strain at break(%) = A1 /Ao x 100

Tensile tester: "INSTRON3367" manufactured by Instron

Corporation, load cell: 500 N

The stretchability of a resin composition (single layer sheet) can be

evaluated to be good if the strain at break is 170% or more.

[0107]

(2) Impact Strength

The impact strength at low temperature and low humidity of the

resin compositions (single layer sheets) obtained in Examples and

Comparative Examples was evaluated in accordance with the following

method.

The 250 pm single layer sheets obtained in Examples and

Comparative Examples were cut into a square shape having a width of 10

cm and a length of 10 cm. Next, each of the cut samples was subjected to

moisture adjustment for two weeks under the condition specified by a

temperature of 0°C and a humidity of 10% RH, then fixed on the sample

table of the impact strength tester described below, and the energy required

for breaking the sample with a pendulum with a 15 kg weight was

measured. The impact strength was calculated by the following formula.

Impact strength (mN/im) = energy required for breaking the sample

(kgf-cm) x 1000 x 0.098/thickness of the sample (pm)

Impact strength tester: "Film Impact Tester" manufactured by Toyo

Seiki Seisaku-sho, Ltd.

The impact strength of a resin composition (single layer sheet) can be evaluated to be good if the measurement is 2.5 mN/pm or more.

[0108]

(3) Adhesive Strength

The adhesive strength of the laminates (multilayer sheets) obtained

in Examples and Comparative Examples was evaluated in accordance with

the following method.

The laminates (L2 layer/L1 layer/L3 layer/L1 layer/L2 layer)

obtained in Examples and Comparative Examples were cut into a strip

shape with a width of 15 mm and a length of 10 cm. The interface between

an L2 layer comprising a thermoplastic resin and an Li layer comprising a

resin composition (one of the two interfaces) and the interface between the

L3 layer comprising the modified starch and an Li layer comprising a resin

composition (one of the two interfaces) were used as the interfaces to be

measured.

Each of the cut samples was subjected to moisture adjustment for

two weeks under the condition specified by a temperature of 230 C and a

humidity of 50% RH, and then the interfaces to be measured were pulled to

peel under the conditions shown below by using the following device. The

adhesive strength of each interface was thereby measured.

Measurement device: "INSTRON3367" manufactured by Instron

Corporation, maximum load cell load: 1 kN

Measurement conditions: temperature: 230 C, humidity: 50% RH,

peeling surface angle: 180

Adhesive strength (N/15im)= energy required for peeling the sample

(kgf) x 9.8

The adhesive strength at the interface between the L2 layer and the

Li layer can be evaluated to be good when it is 25 N/15 mm or more, and

the adhesive strength at the interface between the L3 layer and the Li layer

can be evaluated to be good when it is 15 N/15 mm or more.

[0109]

(4) Thickness

The thickness of each layer of the single layer sheets and the

multilayer sheets obtained in Examples and Comparative Examples was

measured with an optical microscope after sectioning.

Sectioning device: "Rotary Microtome PR-50" manufactured by

Yamato Kohki Industrial Co., Ltd.

Measurement device: "ECLIPSE Ci-E" manufactured by Nikon

Corporation

[0110]

(5) Method for Measuring Viscosity of Polyvinyl Alcohol

In accordance with JIS Z 8803 (falling ball viscometer) and JIS K

6726 (testing methods for polyvinyl alcohol), a 4% aqueous solution of each

of the polyvinyl alcohols in Examples and Comparative Examples was

prepared and its viscosity at 20°C was measured using a Hoppler viscometer

and was taken as the viscosity (200C) in a 4% aqueous solution of the

polyvinyl alcohol.

[0111]

(6) Materials Used

<Modified Starch (A)>

• (A-1): ECOFILM (trademark); corn starch modified with propylene

oxide, amylose content = 70% by mass, manufactured by Ingredion Inc.

• (A-2): National 1658 (trademark); corn starch modified with propylene oxide, amylose content = 20% by mass, manufactured by InInc.

[0112]

<Water-Soluble Polymer (B)>

• (B-1): ELVANOL (trademark) 71-30; polyvinyl alcohol resin, degree

of saponification = 99 mol% or more, viscosity = 27-33 mPa-s (20°C, 4%

aqueous solution), manufactured by Kuraray Co., Ltd.

[0113]

<Polyol Plasticizer (C)>

• (C-1): Sorbitol SG; sorbitol, manufactured by B Food Science Co.,

Ltd.

• (C-2): Xylitol, manufactured by FUJIFILM Wako Pure Chemical

Corporation

• (C-3): Sucrose, manufactured by FUJIFILM Wako Pure Chemical

Corporation

[0114]

<Thermoplastic Resin (D)>

1(D-1): Ecovio (trademark) F2341; mixture of PLA and PBAT, MVR

(Melt Volume Rate) = 2.5 to 7.5 mL/10 min (190°C, 5 kg), manufactured by

BASF

S(D-2): INGEO (trademark) 2003D; PLA, MFR (Melt Flow Rate)= 6

g/10 min (210°C, 2.16 kg), manufactured by Nature Works LLC

• (D-3): SKYGREEN K2012 (trademark); PETG, manufactured by

SK Chemicals

•(D-4): NOVATEC LD (trademark) LC600A; low density

polyethylene, MFR (Melt Flow Rate) = 7 g/10 min (190°C, 2.16 kg),

manufactured by Japan Polyethylene Corporation

•(D-5): NOVATEC PP (trademark) EA7AD; polypropylene, MFR

(Melt Flow Rate) = 1.4 g/10 min (230°C, 2.16 kg), manufactured by Japan

Polypropylene Corporation

Thermoplastic resins (D-1) and (D-2) exhibit biodegradability in a

biodegradability test in accordance with EN13432.

[0115]

<Example 1>

(Preparation of Single Layer Sheet)

A single layer film containing 67% by mass of modified starch (A-1),

23% by mass of modified starch (A-2), and 10% by mass of water-soluble

polymer (B-1) was charged as raw materials to a mill ("Ultra Centrifugal

Mill" ZM100 (manufactured by Retsch). Hereinafter, modified starch (A)

containing 67% by mass of modified starch (A-1) and 23% by mass of

modified starch (A-2) is referred to as modified starch (A'). The average

amylose content of modified starch (A') was 58% by mass.

[0116]

16.7 parts by mass of polyol plasticizer (C-1) and 67.9 parts by mass

of thermoplastic resin (D-1) were added to 15.3 parts by mass of film pieces

pulverized with a mill (containing 90% by mass of modified starch (A') and

10% by mass of water-soluble polymer (B-1)), followed by mixing and

kneading with a twin screw extruder. The screw diameter, the L/D ratio,

the rotation speed, the operation mode, and the temperature profile (Table

1) of the twin screw extruder are shown below, and a schematic view of the

twin screw extruder is shown in FIG. 2. In Example 1, the material (XI) is

a single layer film, and the material (X2) is 16.7 parts by mass of polyol

plasticizer (C-1) and 67.9 parts by mass of thermoplastic resin (D-1).

[0117]

[Table 1] Temperature profile A [C]: C1 C2 C3 C4 C5 IC6 C7 C8 C9C10 C11 Adapter Die 70 70 80 90 200 200 200 200 200 200 200 200 200

Screw diameter: 27mm

L/D ratio: 48

Screw rotation speed: 100 rpm

Operation mode: co-rotation (engaging self-wiping) mode

[0118]

When the mixture was fed to the twin screw extruder, it was fed at a

rate of 4 kg/hour into the barrel through the hopper at C1 via the weight

feeder of the twin screw extruder. The temperature ranges of C5 to C9 are

cooking ranges, and complete gelatinization was completed in these ranges,

and a resin composition was prepared. The film-forming die was disposed

after C11.

[0119]

The resin composition was extruded through a film-forming die of

the twin screw extruder, processed with a cast roll to form a film, and then

wound. Thus, a single layer sheet (L)comprising the resin composition

was produced. The single layer sheet (LI) had a thickness of 250 pm, and

had a composition comprising 13.8% by mass of modified starch (A'), 1.5% by

mass of water-soluble polymer (B-1), 16.7% by mass of polyol plasticizer (C

1), and 67.9% by mass of thermoplastic resin(D-1).

[0120]

(Preparation of Multilayer Sheet)

Separately, in the above-mentioned twin screw extruder, components were mixed and kneaded by the same method as that described above with the following strand die attached to the twin screw extruder at or after C11, and the resulting resin composition was extruded through a multi-hole strand nozzle of the twin screw extruder. The resulting strands were cut with a rotary cutter to yield pellets. The composition of the pellets was the same as that of the single layer sheet (L).

Strand die: 450mm wide coat hanger die

Lip opening: 0.2 mm

Distance between Die and Cast Roll (Air Gap): 10 mm

[0121]

As the L layer, the resulting pellets (comprising 13.8% by mass of

modified starch (A'), 1.5% by mass of water-soluble polymer (B-1), 16.7% by

mass of polyol plasticizer (C-1), and 67.9% by mass of thermoplastic resin

(D-1)) were fed to the single screw extruder (1) shown in Table 2 and

extruded through a multilayer film-forming die. Further, as the L2 layer,

the thermoplastic resin (D-1) pulverized into pellets was fed into the single

screw extruder (2) shown in Table 3 and extruded through the multilayer

film-forming die.

Next, both sides of a sheet (L3 layer, containing 90% by mass of

modified starch (A') and 10% by mass of water-soluble polymer (B-1))

conveyed by a roller type winding machine were coated with the resin

composition for forming an Li layer extruded through the multilayer film

forming die, and further, both sides of the resulting laminate were coated

with the resin for forming an L2 layer extruded through the multilayer film

forming die. The resulting laminate was immediately pressure-bonded to

the sheet (L3 layer) with a pressure roll, and then wound into a roll form by a winding machine. Thus, a laminate (multilayer sheet) was obtained.

The multilayer sheet had a layer configuration having L2 layer [50 Im]/L1

layer [260 pm]/L3 layer [290 pm]/L1 layer [260 im]/L2 layer [50 jim] in this

order. The number in parentheses indicates the thickness of each layer.

[0122]

Single screw extruder (1): extruder manufactured by Research

Laboratory of Plastics Technology Co., Ltd. (screw diameter = 32 mm, L/D

ratio = 28)

Preset Temperature:

[Table 2] Single screw extruder cylinder Adapter Die C1 1C2 =C3 C4 0 100 C 0 180 C 1800 C 180 0 C 180°C 180 0 C Discharge Rate: 2.5 kg/hr

Distance between die and cast roll (Air gap): 150 mm

[0123]

Single screw extruder (2): extruder manufactured by Toyo Seiki

Seisaku-sho, Ltd. (screw diameter =20 mm, L/D ratio = 20)

Preset Temperature:

[Table 3] Single screw extruder cylinder Adapter Die C1 C2 C3 C4 0 150 C 0 180 C 1800 C 180°C 180°C 1800 C Discharge Rate: 0.5 kg/hr

Distance between die and cast roll (Air gap): 150 mm

[0124]

<Examples 2 to 8, 11 and 12, and Comparative Examples 1 to 11>

Single layer sheets (resin compositions) and multilayer sheets

(laminates) were obtained by the same method as in Example 1 except that

the contents of modified starch (A) and water-soluble polymer (B), and the

types and the contents of polyol plasticizer (C) and thermoplastic resin (D)

were adjusted as shown in Table 5. In Examples 8 and 12, taking into

consideration the type of thermoplastic resin (D), the sites with the

indication of 200 0C in the twin screw extruder shown in Table 1 (C5 through

C11, adapter and die) were changed to 2200 C or 230 0 C, and the sites with

the indication of 1800C in the single screw extruder (1) shown in Table 2

and the single screw extruder (2) shown in Table 3 (C2 to C4, adapter and

die) were changed to 220°C or 230°C. In Table 5, all starches (A) are all

modified starch (A'), and all water-soluble polymers (B) are all water-soluble

polymer (B-1).

[0125]

<Example 9>

(Preparation of Multilayer Structure)

As the L2 layer, the thermoplastic resin(D-1) pulverized into pellets

was fed into the single screw extruder (3) shown in Table 4 and extruded

through the multilayer film-forming die. Both sides of a sheet (L3 layer,

containing 90% by mass of modified starch (A') and 10% by mass of water

soluble polymer (B-1)) conveyed by a roller type winding machine were

coated with the resin (L2 layer) extruded through the multilayer film

forming die, and immediately pressure-bonded to the sheet (L3 layer) with a

pressure roll, and then wound into a roll form by a winding machine. Thus,

a multilayer structure was obtained. The multilayer structure had a layer

configuration having L2 layer [50 pm]/L3 layer [450 pm]/L2 layer [50 im] in

this order. The number in parentheses indicates the thickness of each layer.

[0126]

Single screw extruder (3): extruder manufactured by Research

Laboratory of Plastics Technology Co., Ltd. (32 mm in diameter, L/D =28)

Preset Temperature:

[Table 4] Single screw extruder cylinder Adapter Die C1 1C2 =C3 C4 0 150 C 0 180 C 1800 C 180 0 C 180°C 1800 C Discharge Rate: 0.5 kg/hr

Distance between die and cast roll (Air gap): 150 mm

[0127]

(Recycling of Multilayer Structure)

The multilayer structure obtained above was pulverized with a mill

("Ultra Centrifugal Mill", ZM100 manufactured by Retsch). 16.7 parts by

mass of polyol plasticizer (C-1) and 64.5 parts by mass of thermoplastic

resin (D-1) were added to 18.8 parts by mass of film pieces pulverized with a

mill [containing 73.6% by mass of modified starch (A'), 8.2% by mass of

water-soluble polymer (B-1), and 18.2% by mass of thermoplastic resin (D

1)], followed by mixing and kneading with a twin screw extruder (performed

under the condition of Table 1 shown in Example 1). Thus, a resin

composition with the same composition as in Example 1 was obtained.

Using the resulting resin composition, a single layer sheet (resin

composition) and a multilayer sheet (laminate) were obtained in the same

manner as in Example 1. In Example 9, the material (XI) is a multilayer

structure, and the material (X2) comprises 16.7 parts by mass of polyol

plasticizer (C-1) and 64.5 parts by mass of thermoplastic resin (D-1).

[0128]

<Example 10>

(Recycling of Laminate)

The multilayer sheet (laminate) obtained in Example 1 was

pulverized with a mill ("Ultra Centrifugal Mill", ZM100 manufactured by

Retsch). 13.1 parts by mass of polyol plasticizer (C-1) and 49.1 parts by

mass of thermoplastic resin (D-1) were added to 37.7 parts by mass of film

pieces pulverized with a mill [containing 36.6% by mass of starch (A'), 4.0%

by mass of water-soluble polymer (B-1), 9.5% by mass of polyol plasticizer

(C-1), and 49.8% by mass of thermoplastic resin(D-1)), followed by mixing

and kneading with a twin screw extruder (performed under the condition of

Table 1 shown in Example 1). Thus, a resin composition with the same

composition as in Example 1 was obtained. Using the resulting resin

composition, a single layer sheet (resin composition) and a multilayer sheet

(laminate) were obtained in the same manner as in Example 1. In

Example 10, the material (X1) is the multilayer sheet (laminate) obtained in

Example 1, and the material (X2) comprises 13.1 parts by mass of polyol

plasticizer (C-1) and 49.1 parts by mass of thermoplastic resin(D-1).

[0129]

<Example 13>

Under the following conditions, the multilayer sheet obtained in

Example 1 was molded into a coffee capsule container.

Device: pressure and vacuum thermoforming machine (FKS-0632

20)

Thermoforming temperature: 115°C

Draw ratio: 0.5

Pressure: 0.5 MPa

Compression time: 4 seconds

[0130]

Using the single layer sheets and the multilayer sheets obtained in

Examples 1 to 12 and Comparative Examples 1 to 11, strain at break,

impact strength, and adhesive strength were measured. The results and

the pass ranges are shown in Table 5. The addition amounts of the starch

(A) and the water-soluble polymer (B), the types and the addition amounts

of the polyol plasticizer (C) and the thermoplastic resin (D), and the mass of

the modified starch (A)/the mass of the polyol plasticizer (C) (A/C) are shown

in Table 5.

F2-dL .- 00~ 10 o C' m 00Co (m 001 in 0.

CD C

~~~c t D0 0 U-)" 0 10, Ca) Al A Co~ A A A A A A A A A

b a) 4- 4

4 0 = UD l 00 0 0 0 0 0 0 0 0 W N r-(00 LO 00 L

El Al

Ci2 o X . 0 CO UCo Co, Co Co Co CO Co 0 C C

C) CC) 0 000 CO 0 00000 0 0 0 CAC

o~ z ripCo 4 4~ 0 r-o

'

Cd~ Co w 4o>w>1D w w>w>41C CD -4 i6

0

0 1 ko W S ' 4 Co ' - I _q ' i -4 o- -4 -4 -4 -4 -4 _q~

0rj 00000 Co Co Co6 Co6 Co Co6 Co Co6 0 C Clm- .-4 Co- c- i - '

o ~ 0 0 .d

M P, 58

Lo m~ 10 0 00 ) ro0 -4 -1 -41 r-4 r-4 Co

oY m co co m t A A A A A Nl

to mO r-q 1O L- CJo to Co -4 C6 cli r4 o6 C6 '-4 r4

0 0 1O 0 LO 10 10 0) Co N co

~4 CO cz r- 1-0 10 1O 6l 0 0 0 - 10 1 10

r-4 06'-4 L6O~

10 m~ Nl N t- m~ t-> t- CD CD CO3 CoCr o Co

10 0- LO 0D CO, i as

r-4 4 Co4 r-4

1-4 10 10)n1 10

It L OFl > 0->0

m m' c ml c6 pq Co 1 z .0 10 10

1 El- >4 - 1 4 l Ox C0 -x 11 l

[0131]

As shown in Table 5, the single layer sheets obtained in Examples 1

to 12 were confirmed to have good evaluations in both stretchability and

impact strength at low temperature and low humidity. In contrast, the

single layer sheets obtained in Comparative Examples 1 to 11 were

confirmed to be poor in both stretchability and impact strength, or in one of

them. The multilayer sheets obtained in Examples 1 to 12 were confirmed

to be good in adhesive strength at an interface. Therefore, the resin

composition of the present invention was found to be capable of achieving

both good stretchability and good impact strength at low temperature and

low humidity, and laminates comprising a layer comprising the resin

composition were found to have good adhesive strength at an interface.

Further, using the multilayer structure in Example 9 and using the

laminate of the present invention in Example 10, resin compositions with

the same composition as that of Example 1, and single layer sheets using

them were prepared. The single layer sheets obtained in Examples 9 and

10 exhibited good evaluation results similar to those in Example 1. From

this result, it was also found that the resin composition and the laminate of

the present invention are superior in recyclability.

DESCRIPTION OF REFERENCE SIGNS

[0132]

1, 3, 5: Laminate (layer configuration)

2, 4: Resin composition

8: Twin screw extruder

9:Hopper

10: Liquid addition nozzle

11: Resin thermometer

12: Resin pressure gage

13: Adapter

14: Die

Claims (18)

1. A resin composition comprising:

6 to 45 parts by mass of a modified starch (A);

1 to 5 parts by mass of a water-soluble polymer (B);

1 to 50 parts by mass of a polyol plasticizer (C); and

5 to 80 parts by mass of a thermoplastic resin (D) different from the

water-soluble polymer (B),

wherein the following formula (1) is satisfied,

0 < mass of(A)/mass of (C) < 1 (1)

and the total content of the (A), (B), (C) and (D) is 100 parts by mass.

2. The resin composition according to claim 1, wherein the total

content of the modified starch (A), the water-soluble polymer (B), the polyol

plasticizer (C) and the thermoplastic resin (D) is 80% by mass or more with

respect to the mass of the resin composition.

3. The resin composition according to claim 1 or 2, wherein the

modified starch (A) has an average amylose content of 45% by mass or more.

4. The resin composition according to any one of claims 1 to 3,

wherein the water-soluble polymer (B) is a polyvinyl alcohol-based resin.

5. The resin composition according to any one of claims 1 to 4,

wherein the polyol plasticizer (C) comprises at least one selected from the group consisting of sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, and glycerol..

6. The resin composition according to any one of claims 1 to 5,

wherein the thermoplastic resin (D) comprises at least one selected from a

polyolefin-based resin and a polyester-based resin.

7. The resin composition according to any one of claims 1 to 6,

wherein the thermoplastic resin (D) comprises a biodegradable

thermoplastic resin having biodegradability in a biodegradability test in

accordance with EN13432.

8. A film or sheet comprising the resin composition according to

any one of claims 1 to 7.

9. A laminate comprising:

an Li layer comprising the resin composition according to any one of

claims 1 to 7; and

an L2 layer being different from the L layer and comprising 50% by

mass or more of the same thermoplastic resin (D) as that of the Li layer

and/or an L3 layer comprising 50% by mass or more of a modified starch.

10. The laminate according to claim 9, wherein the laminate

comprises, in at least a part thereof, a layer configuration selected from the group consisting of: a layer configuration having L3 layer/L1 layer/L3 layer in this order; a layer configuration having L2 layer/L1 layer/L3 layer in this order; and a layer configuration having L2 layer/L1 layer/L2 layer in this order.

11. The laminate according to claim 9 or 10, wherein at least one

Li layer has a thickness of 10 to 450 im, at least one L2 layer has a

thickness of 5 to 500 pm, and at least one L3 layer has a thickness of 20 to

800 pm.

12. The laminate according to any one of claims 9 to 11, wherein

the total thickness of the Li layer is 10 to 1000 pm, the total thickness of

the L2 layer is 5 to 1000 pm, and the total thickness of the L3 layer is 20 to

2000 pm.

13. A method for producing the resin composition according to any

one of claims 1 to 7, which comprises a step of mixing a material (X1)

comprising a modified starch (A), a water-soluble polymer (B), and

optionally a polyol plasticizer (C) and/or a thermoplastic resin (D), and a

material (X2) comprising a polyol plasticizer (C) and/or a thermoplastic

resin (D).

14. The method according to claim 13, wherein in the step, the

material (X1) comprises at least the modified starch (A), the water-soluble polymer (B) and the thermoplastic resin (D), and the material (X2) comprises at least the polyol plasticizer (C).

15. The method according to claim 13 or 14, wherein the step is a

step of melt-kneading the material (X1) that is a laminate and the material

(X2).

16. The method according to claim 15, wherein the laminate is the

laminate according to any one of claims 9 to 12.

17. The method for producing the laminate according to any one of

claims 9 to 12, which comprises a step of co-extruding the Li layer and

another layer comprising the L2 layer and/or the L3 layer.

18. A container comprising the laminate according to any one of

claims 9 to 12.