JP2019099190A - Fusion method, packing method and packing body of heat-fusable film - Google Patents

Abstract

To improve the fusion strength of the heat-fusable film without changing the configuration of the sealant layer itself of the heat-fusable film.SOLUTION: A fusion method of a heat-fusable film comprises: adding aqueous solution 2 including cellulose nanofiber, and water-soluble polymer which is negatively charged when dissolved into water, onto a heat-fusable sealant layer 12 of the heat-fusable film 1 having the sealant layer 12; and then fusing the sealant layer 12.SELECTED DRAWING: Figure 2

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method of fusing a heat fusion film, a packaging method, and a package.

For example, when packaging an article such as food or sundries, the sealant layer of the heat-fusion film is thermally bonded using a heat-fusion film in which a sealant layer having heat-fusion property is laminated on a predetermined base material layer. By fusion bonding, packaging is performed so as to cover the article to be packaged.
In the case of such packaging, in order to prevent the fusion-bonded portion from peeling off, it is necessary to increase the fusion strength of the sealant layers. Then, the invention which intended that fusion | melting strength is intended to be improved is known by using what has strong fusion | fusion strength about the structure of sealant layer itself (for example, refer patent document 1).

Unexamined-Japanese-Patent No. 2006-21368

  However, in the heat fusion film as described above, it is necessary to change the configuration of the sealant layer in the manufacturing process, and the fusion strength can not be increased for the existing heat fusion film.

  An object of the present invention is to improve the fusion strength of a heat fusion film without changing the configuration of the sealant layer itself of the heat fusion film.

In order to solve the above-mentioned subject, invention of Claim 1 is a fusion method of a heat fusion film,
In the sealant layer of a heat sealing film having a heat sealing property sealant layer,
After addition of a solution containing cellulose nanofibers, and a water-soluble polymer that is negatively charged when dissolved in water,
The sealant layer is fused.
According to the first aspect of the present invention, the fusion bonding strength of the heat fusion film can be improved without changing the configuration of the sealant layer itself of the heat fusion film.

The invention according to claim 2 is the fusion method of the heat fusion film according to claim 1,
The solution is added to the sealant layer of either or both of the heat-fusion films, and then the heat-fusion films are fused by the sealant layer.
According to the second aspect of the present invention, the fusion strength of the heat-fusion films can be improved without changing the configuration of the sealant layer itself of the heat-fusion film.

The invention according to claim 3 is the fusion method of the heat fusion film according to claim 2,
Amount added of the cellulose nanofibers, by summing the mutually additional amount to both fused in part of the heat-fusible film, wherein the 28μg / cm ² or more and 1000 [mu] g / cm ² or less .
According to the third aspect of the present invention, the fusion bonding strength of the heat fusion films can be further improved without changing the configuration of the sealant layer itself of the heat fusion film.

The invention according to claim 4 is the fusion bonding method of a heat fusion film according to claim 2 or 3,
The addition amount of the water-soluble polymer is 28 μg / cm ² or more and 5400 μg / cm ² or less, which is the total of the addition amounts of the heat-fusion film to the mutually fused portions. Do.
According to the fourth aspect of the present invention, the fusion strength of the heat-fusion films can be further improved without changing the configuration of the sealant layer itself of the heat-fusion film.

The invention according to claim 5 is the fusion method of a heat fusion film according to any one of claims 1 to 4,
The water-soluble polymer is characterized by being carboxymethylcellulose.
According to the fifth aspect of the present invention, the fusion bonding strength of the heat fusion film can be further improved without changing the configuration of the sealant layer itself of the heat fusion film.

The invention according to claim 6 is
The heat-sealable film according to any one of claims 1 to 5, wherein a heat-sealable film having one or more heat-sealable sealant layers is disposed so as to cover the article to be packaged. In the packaging method, the sealant layer is fused by a method of fusing a film.
According to the sixth aspect of the present invention, it is possible to provide a packaging method in which the fusion strength of the heat fusion film is improved without changing the configuration of the sealant layer itself of the heat fusion film.

The invention according to claim 7 is the package body,
A package in which a heat fusion film having a heat fusion sealant layer covers one or more sheets by the sealant layer so as to cover the article to be packaged, and the fusion-bonded portion of the sealant layer Is characterized in that it contains cellulose nanofibers and a water-soluble polymer that is negatively charged when dissolved in water.
According to the seventh aspect of the invention, it is possible to provide a package in which the fusion strength of the heat fusion film is improved without changing the configuration of the sealant layer itself of the heat fusion film.

  According to the present invention, the fusion bonding strength of the heat fusion film can be improved without changing the configuration of the sealant layer itself of the heat fusion film.

It is sectional drawing of the heat sealing | fusion film which concerns on embodiment. (A) is sectional drawing which shows the state which apply | coated the solution to the sealant layer side of the heat sealing | fusion film which concerns on embodiment. (B) is a sectional view showing a state where the solution is applied to the sealant layer side of the heat fusion film according to the embodiment, and then the other heat fusion films are stacked so that the sealant layers face each other. (A) is the perspective view which looked at the pillow packaging which concerns on embodiment from diagonally upper direction, (b) is the perspective view which looked at the pillow packaging which concerns on embodiment from diagonally downward.

  Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 3. However, the technical scope of the present invention is not limited to the illustrated example.

[Heat fusion film]
The heat-fusion film 1 according to the embodiment of the present invention, as shown in FIG. 1, is a laminate of a base material layer 11 and a sealant layer 12. In addition, in bonding of the base material layer 11 and the sealant layer 12, well-known arbitrary methods, such as extrusion lamination, dry lamination, a wet lamination, can be used.

(Base material layer)
The base material layer 11 is a portion other than the sealant layer 12 of the heat fusion film 1, and the material is not particularly limited, and any film may be used as long as the melting point shows a value not melting at the time of heat sealing. For example, a film formed of polyethylene terephthalate (PET), biaxially oriented polypropylene (OPP) or the like is used.
In addition, it is not necessary to be a single layer as a base material layer, and multiple types of film may be laminated | stacked.
The thickness of the substrate layer 11 is preferably 5 μm to 50 μm, and more preferably 10 μm to 30 μm. With this thickness, a sufficient barrier function can be obtained with regard to external stimulation and transpiration.

(Sealant layer)
The sealant layer 12 may be a film formed of any material having heat fusion property at the time of heat sealing, for example, formed of linear low density polyethylene (LLDPE) or non-oriented polypropylene (CPP) Film can be used.
The thickness of the sealant layer 12 is preferably 20 μm to 100 μm, and more preferably 40 μm to 60 μm. With this thickness, sufficient seal strength can be obtained.

[solution]
Solution 2 is obtained by adding cellulose nanofibers (hereinafter referred to as "CNF") and a water-soluble polymer to water.

(CNF)
CNF refers to fine cellulose fibers obtained by disintegrating pulp fibers, and generally refers to cellulose fibers containing cellulose fine fibers having a nanosize (1 nm or more and 1000 nm or less) in fiber width, but the average fiber width Are preferably fibers of 100 nm or less.

The calculation of the average fiber width uses, for example, a fixed number of number averages, a median, a mode diameter (mode value), etc., but the above-mentioned fiber widths are measured as follows.
First, 100 ml of an aqueous dispersion of cellulose nanofibers having a solid concentration of 0.01 to 0.1% by mass is filtered through a membrane filter made of Teflon (registered trademark), and 100 ml of ethanol once and 20 ml of t-butanol three times Replace.
Next, it is lyophilized and osmium coated to make a sample. This sample is observed with an electron microscope SEM image at a magnification of 5000 times, 10000 times or 30000 times depending on the width of the fiber to be constructed. Specifically, two diagonals are drawn on the observation image, and three straight lines passing the intersections of the diagonals are arbitrarily drawn. Furthermore, the width of a total of 100 fibers intersecting with the three straight lines is measured visually. And let the median diameter (median diameter) of a measured value be an average fiber diameter.

  Pulp fibers that can be used to produce CNF include chemical pulp such as hardwood pulp (LBKP) and softwood pulp (NBKP), bleached thermomechanical pulp (BTMP), stone ground pulp (SGP), and pressed stone ground pulp (PGW) ), Refiner ground pulp (RGP), chemiground pulp (CGP), thermoground pulp (TGP), grand pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), refiner mechanical pulp (RMP) Etc. Waste paper manufactured from mechanical pulp, tea waste paper, kraft envelope waste paper, magazine waste paper, newspaper waste paper, flyer waste paper, office waste paper, corrugated waste paper, top white waste paper, Kent waste paper, imitation waste paper, ground waste paper, waste paper waste paper etc. Deinking pulp obtained by deinking pulp and waste paper pulp Such as-flops (DIP), and the like. These may be used alone or in combination of two or more, as long as the effects of the present invention are not impaired.

Examples of methods for producing CNF include mechanical methods such as high-pressure homogenizer method, microfluidizer method, grinder grinding method, bead mill freeze grinding method, ultrasonic fibrillation method, etc., but are limited to these methods is not.
For example, the pulp fiber may be subjected to mechanical treatment such as defibrillation treatment, and may be subjected to chemical treatment such as carboxymethylation or enzyme treatment.
Alternatively, the CNF subjected to the chemical treatment or the enzyme treatment may be subjected to a mechanical disintegration treatment.

  The concentration of CNF in solution 2 is preferably 0.01% to 2.0%, and more preferably 0.1% to 1.8%. If it is less than 0.01%, the application amount of the solution necessary for producing the effect is increased, it is easy to leak when it is fused, and if it is more than 2.0%, the CNF is easily aggregated and the effect is rather Is hampered.

(Water soluble polymer)
As the water-soluble polymer, for example, carboxymethylcellulose (hereinafter referred to as "CMC"), glycerin, sodium hyaluronate, hydroxyethylcellulose, methylcellulose and the like are used. As a water-soluble polymer, any substance can be used as long as it is a substance that takes a negative charge when dissolved in water, but CMC is structurally similar to CNF and easily binds to CNF, It is preferable to use CMC because the effect of preventing aggregation of CNF can be expected compared to other water-soluble polymers.
Such a water-soluble polymer makes it easier for the molecules to be separated sterically by electrostatic interaction by binding a negatively charged water-soluble polymer to the OH group of CNF, thereby preventing aggregation of CNF , Can enhance its effect.
In addition, when CNF is a thing which is not scientifically processed only by the disintegration process of a mechanical method, since it is easy to aggregate, it becomes essential to add water soluble polymer. On the other hand, since it is difficult to aggregate if it is a chemically modified CNF that prevents aggregation of CNF by changing the OH group of CNF such as TEMPO oxidation, carboxymethylation, etc., it is essential to add a water-soluble polymer Absent.

  The concentration of the water-soluble polymer in the solution 2 is preferably 0.01% to 20%, and more preferably 0.1% to 18%. If it is less than 0.01%, the dispersing effect to CNF is not sufficient, and if it is more than 20%, the solution viscosity may increase, and it may be difficult to handle depending on the application.

[Fusion method]
When the heat fusible films 1 and 1 are fused, as shown in FIG. 2A, first, the solution 2 is applied to the sealant layer 12 side of the portion of the heat fusible film 1 to be fused. Apply At this time, the coating amount of the solution 2 is preferably 50 μg / cm ² or more and 26.6 mg / cm ² or less. If it is less than 50 μg / cm ² , the adhesive strength is not sufficiently improved, and if it exceeds 26.6 mg / cm ² , the solution 2 leaks out during fusion and heat sealing becomes difficult.
In addition, the CNF is preferably 28 to 1000 μg / cm ² , more preferably 90 to 450 μg / cm ² , by determining the coating amount corresponding to the concentration of CNF and the water-soluble polymer in solution ² . Make it a coating amount. When the amount is less than 28 μg / cm ² , the adhesive strength is not sufficient, and when the amount is more than 1000 μg / cm ² , CNFs are easily aggregated, and the effect is hindered.
The amount of water-soluble polymer applied is preferably 28 to 5400 μg / cm ² , more preferably 90 to 1350 μg / cm ² . If it is less than 28 μg / cm ^2, it is not sufficient to prevent the aggregation of CNF, and if it is more than 5400 μg / cm ² , the solution viscosity increases and handling becomes difficult.

Subsequently, as shown in FIG. 2 (b), the heat fusion film 1 coated with the solution 2 and the other heat fusion film 1 are overlapped so that the sealant layer 12 side faces each other, and the heat fusion film A general hand sealer is applied to fuse the heat fusion films 1 and 1 with each other.
At this time, it is desirable to fuse at a temperature of 140 ° C. to 150 ° C. for 3 seconds. In addition, after the solution 2 is applied, before the film 2 is dried, it is necessary to fuse the heat fusion films 1 and 1 to each other.
The solution 2 may be applied to the entire surface of the portion to be fused, but is more preferably applied in the form of dots. If it is in the form of dots, it can be applied uniformly without waste, and the solution 2 can be prevented from leaking from between the films.

In the above, the case where the solution 2 is applied to only one of the heat fusible films 1 and 1 is described, but the solution 2 is a sealant of a portion of the heat fusible films 1 and 1 to be fused. It may be applied to the layer 12 side.
In this case, for CNF and the water-soluble polymer, the coating amounts on both of the heat-fusion films 1 and 1 to be fused to each other are summed up to be within the above-mentioned coating amount range. . That is, the application amount means the content of CNF or water-soluble polymer per unit area of the fused part in the state where the heat-fused films 1 and 1 are fused.

  Further, the heat fusion film 1 is not limited to the case where a plurality of heat fusion films 1 are used as described above. For example, a single heat fusion film 1 is fused in a folded state with the sealant layer 12 turned inside and folded. Also in the case of the above, it is possible to use the fusion method according to the present invention.

[Packaging method and package]
It does not specifically limit as a packaging method at the time of packaging an article using the fusion method of heat fusion film 1, 1 concerning an embodiment, and a package formed using the said packaging method, It is not limited. The fusion film 1 can be used in any case for packaging an article.
For example, two substantially congruent rectangular heat-sealable films 1, 1 are stacked, and three sides are fused using the fusing method according to the above embodiment to form a bag, which is then to be packaged. The article is placed and the other side is fused using the fusion method according to the above-described embodiment, thereby storing the article in the sealed bag-like package formed of the heat fusion film 1, 1 be able to.
Also, for example, by wrapping the article to be packaged using a single heat fusion film 1 and fusing the ends of the heat fusion film, the shape of the article to be packaged can be fitted. To form a package.
Further, for example, in the pillow package 3 used for packaging a wet sheet or the like as shown in FIG. 3, the end seal portions 31, 31 and the center seal portion 32, and the seal portion of the gusset package according to the present embodiment. A fusion method of a fusion film can be used.

[Effect of the embodiment]
According to the heat fusion film fusion method of the present embodiment, when fusing the heat fusion films 1, 1 with the sealant layers 12, 12, the CNF and the water-soluble polymer are formed in the fusion part. When the sealant layer 12, 12 is melted by heat due to the application of the solution containing CNF and a water-soluble polymer into a resin such as LLDPE or CPP that forms the sealant layer, the state in which these are mixed In the above, the resin forming the sealant layer will be solidified again.
In this case, the moisture evaporates at the moment of heat application, and CNFs are bonded at that time, but since the hydrogen bond between CNFs is stronger than the bond between the resins, heat fusion is performed. It is possible to increase the fusion strength between the films.
In addition, even if the solution does not contain a water-soluble polymer, CNF changes the OH group of CNF such as TEMPO oxidation, carboxymethylation, etc. as long as the CNF is chemically modified to prevent aggregation of CNF, the above effect can be obtained. Although it can be obtained, when using a solution containing a water-soluble polymer in addition to CNF, the above effects can be obtained regardless of the nature of CNF.
Also, in this case, the above effects can be obtained only by applying a solution containing CNF and a water-soluble polymer to the fusion surface while using a heat fusion film having a general sealant layer made of LLDPE, CPP, etc. Since the existing heat fusion film can be used as it is without changing the configuration of the sealant layer of the heat fusion film itself, the increase in cost can be minimized.
Further, even when a solution containing CNF and a water-soluble polymer is applied to the fusion-bonded portion when the heat-fusion films 1 and 1 are fused by the sealant layers 12 and 12, for example, using this There is no hindrance to the disposal of the formed package, no discoloring of the fused portion of the sealant layer, and the appearance of the package.

[Modification]
In the above, although the case where the heat-fusion film 1 and 1 are fused is described, the sealant layer 12 is also used when the heat-fusion film 1 is fused to an article other than the heat-fusion film 1. The adhesive strength can be enhanced by applying the solution 2 to the fusion-bonded portion of
For example, when a lid such as a cup or tray formed of polypropylene, PET or the like is covered with a film-like lid, the lid is formed using the heat fusion film 1 and then the sealant layer is formed. The adhesive strength between the container and the lid can be improved by applying the solution 2 to the fusion part with the container 12 and fusing the solution 2 with the container.

  Next, the heat-sealed films 1, 1 are fused with each other by using the heat-sealed films according to the examples and comparative examples of the present invention, and the results of evaluating the fused strength will be described. EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Test 1]
The heat fusible films were fused together as in the following examples and comparative examples.

Example 1
A film formed of polyethylene terephthalate (PET) as a base material layer, a film formed of linear low density polyethylene (LLDPE) as a sealant layer, and thermally formed by laminating these by dry lamination A fusion film (PET 12 / LLDPE 50) was prepared. The thickness of the heat fusion film is 62 μm in total, which is 12 μm for the base layer and 50 μm for the sealant layer.
What cut the said heat-fusion film in the rectangular shape of 5 cm of long sides and 2 cm of short sides was prepared as 2 pieces as a test piece.
A solution was prepared in which CNF was mixed at 1.7%, CMC at 1.7%, and water at 96.6%.
The CNF used here is a NNFP 100% CNF. The CNF having an average fiber width (median diameter) of 49 nm was used. This CNF is obtained by refining NBKP and roughly defibrillating it, and then treating it four times using a high-pressure homogenizer to defibrillate it. The method of measuring the fiber width of CNF is as described in paragraph 0021.
Moreover, CMC used here is CMC1330 (Daicel Corporation).
A total of 500 mg of the solution was applied substantially uniformly over the entire sealant layer side of the test piece. In this case the coating amount is per CNF, per 850μg / cm ^2, CMC, a 850μg / cm ^2.
Immediately after applying the solution, the other test specimen is overlapped on the test specimen coated with the above solution so that the sealant layers face each other, using a hand sealer (NL-331JC manufactured by Ishizaki Electric Manufacturing Co., Ltd.) The test pieces were fused at five locations at a width of 0.5 cm in the long side direction of the test piece and at substantially equal intervals in the long side direction of the test piece over the entire short side direction (2 cm) of the test piece. Specific conditions are a temperature of 145 ° C., a time of 3 seconds, and a pressure of 2 N / m ² .

(Comparative example 1)
The same test piece as in Example 1 was prepared.
A solution was prepared by mixing CNF at 2.0% and water at a ratio of 98.0%. The CNF used is the same as in Example 1.
A total of 500 mg of the solution was applied substantially uniformly over the entire sealant layer side of the test piece. In this case, the application amount is 1000 μg / cm ² per CNF.
Immediately after the application of the solution, the other test piece was overlaid on the test piece coated with the above-mentioned solution so that the sealant layers face each other, and was fused as in Example 1.

(Comparative example 2)
The same test piece as in Example 1 was prepared.
A solution was prepared by mixing 2.0% of CMC and 98.0% of water. The CMC used is the same as in Example 1.
A total of 500 mg of the solution was applied substantially uniformly over the entire sealant layer side of the test piece. In this case, the application amount is 1000 μg / cm ² per CMC.
Immediately after the application of the solution, the other test piece was overlaid on the test piece coated with the above-mentioned solution so that the sealant layers face each other, and was fused as in Example 1.

(Comparative example 3)
The same test piece as in Example 1 was prepared.
I prepared water.
A total of 500 mg of water was applied substantially evenly over the entire sealant layer side of one of the test pieces.
Immediately after the application of water, the other test piece was overlaid on the above-described test piece coated with water such that the sealant layers face each other, and was fused as in Example 1.

(Comparative example 4)
The same test piece as in Example 1 was prepared.
Two test pieces were stacked so that the sealant layers face each other, and were fused as in Example 1.

{contents of the test}
The bonded test pieces of the above Examples and Comparative Examples are cut in half in the short side direction to form a rectangular shape having a short side of 1 cm and a long side of 5 cm, and The fusion strength was individually measured for each of five places, and the average value was calculated for each of the examples and the comparative examples.
Specifically, using a tensile tester (TENSIRON RTG 1210 manufactured by A & D), the fused test pieces are pinched by the chucks of the tensile tester at each fusion location, the distance between chucks 50 mm, speed 500 mm The maximum load point when the fusion of the sheet material at each fusion-bonded location was peeled off was measured under the condition of / min, and the average ground was calculated for each of the examples and the comparative examples.

  The results of the study are shown in Table I.

(Evaluation)
According to the comparison between Example 1 and Comparative Examples 1 to 4, the sealant layer of the heat-fusion film was coated with a solution containing CNF and a water-soluble polymer (CMC) which takes a negative charge when dissolved in water. Thus, it is understood that the fusion strength of the heat-fusion films can be improved by fusing the heat-fusion films.

[Test 2]
Heat fusion films were adhered to each other as in the following examples and comparative examples.

(Example 2)
A film formed of polyethylene terephthalate (PET) as a base material layer, a film formed of linear low density polyethylene (LLDPE) as a sealant layer, and thermally formed by laminating these by dry lamination A fusion film (PET 12 / LLDPE 50) was prepared. The thickness of the heat fusion film is 62 μm in total, which is 12 μm for the base layer and 50 μm for the sealant layer.
Two pieces of the heat fusion film were cut into a rectangular shape having a long side of 20 cm and a short side of 15 cm, and two sheets were prepared as test pieces.
A solution was prepared in which CNF was mixed at 1.7%, CMC at 1.7%, and water at 96.6%.
The CNF and CMC used here are the same as those used in Test 1.
A total of 1 g of the solution was applied substantially uniformly over the entire sealant layer side of one of the test pieces. In this case the coating amount is per CNF, per 56.7μg / cm ^2, CMC, the 56.7μg / cm ^2.
Immediately after applying the solution, the other test specimen is overlapped on the test specimen coated with the above solution so that the sealant layers face each other, using a hand sealer (NL-331JC manufactured by Ishizaki Electric Manufacturing Co., Ltd.) The test pieces were fused at 20 locations at a width of 0.5 cm in the long side direction of the test piece and at substantially equal intervals in the long side direction of the test piece over the entire short side direction (15 cm) of the test piece. Specific conditions are a temperature of 145 ° C., a time of 3 seconds, and a pressure of 2 N / m ² .

(Example 3)
The same test piece and solution as in Example 2 were prepared.
A total of 2 g of the solution was applied substantially uniformly over the entire sealant layer side of the test piece. In this case the coating amount is per CNF, per 113.3μg / cm ^2, CMC, the 113.3μg / cm ^2.
Immediately after the application of the solution, the other test piece was overlaid on the test piece coated with the above-described solution so that the sealant layers face each other, and was fused as in Example 2.

(Example 4)
The same test piece and solution as in Example 2 were prepared.
A total of 4 g of the solution was applied substantially uniformly over the entire sealant layer side of the test piece. In this case the coating amount is per CNF, per 226.7μg / cm ^2, CMC, the 226.7μg / cm ^2.
Immediately after the application of the solution, the other test piece was overlaid on the test piece coated with the above-described solution so that the sealant layers face each other, and was fused as in Example 2.

(Example 5)
The same test piece and solution as in Example 2 were prepared.
A total of 6 g of the above solution was applied substantially uniformly over the entire surface on one sealant layer side of the above test piece. In this case the coating amount is per 340μg / cm ^2, CMC per CNF, a 340μg / cm ^2.
Immediately after the application of the solution, the other test piece was overlaid on the test piece coated with the above-described solution so that the sealant layers face each other, and was fused as in Example 2.

(Example 6)
The same test piece and solution as in Example 2 were prepared.
A total of 8 g of the solution was applied substantially uniformly over the entire sealant layer side of one of the test pieces. In this case the coating amount is per CNF, per 453.3μg / cm ^2, CMC, the 453.3μg / cm ^2.
Immediately after the application of the solution, the other test piece was overlaid on the test piece coated with the above-described solution so that the sealant layers face each other, and was fused as in Example 2.

(Example 7)
The same test piece and solution as in Example 2 were prepared.
A total of 10 g of the solution was applied substantially uniformly over the entire sealant layer side of the test piece. In this case the coating amount is per CNF, per 566.7μg / cm ^2, CMC, the 566.7μg / cm ^2.
Immediately after the application of the solution, the other test piece was overlaid on the test piece coated with the above-described solution so that the sealant layers face each other, and was fused as in Example 2.

(Comparative example 5)
The same test piece as in Example 2 was prepared.
The two test pieces were stacked so that the sealant layers face each other, and were fused as in Example 2.

{contents of the test}
The bonded test pieces of the above Examples and Comparative Examples are equally divided into 10 in the short side direction and cut into a rectangular shape having a short side of 1.5 cm and a long side of 20 cm. The adhesive strength was individually measured for each of (each of 20 places), and the average value was calculated for each example and comparative example.
Specifically, using a tensile tester (TENSIRON RTG 1210 manufactured by A & D), the fused test pieces are pinched by the chucks of the tensile tester at each fusion location, the distance between chucks 50 mm, speed 500 mm The maximum load point when the fusion of the sheet material at each fusion-bonded location was peeled off was measured under the condition of / min, and the average ground was calculated for each of the examples and the comparative examples.

  The results of the test are shown in Table II.

(Evaluation)
According to the comparison between Examples 2 to 7 and Comparative Example 5, the sealant layer of the heat-fusion film is coated with a solution containing CNF and a water-soluble polymer (CMC) which is negatively charged when dissolved in water. Thus, it is understood that the fusion strength of the heat-fusion films can be improved by fusing the heat-fusion films.
Further, the comparative Examples 2 to 7, the coating amount of CNF and CMC is most preferably 226.7μg / cm ² per 226.7μg / cm ^2, CMC per CNF, then 340μg / cm ² per CNF, CMC in 113.3μg / cm ² is preferably 340μg / cm ^2, and then is preferably 453.3μg / cm ² per 453.3μg / cm ^2, CMC per CNF, then per 113.3μg / cm ^2, CMC per CNF per preferably there, then is preferably 56.7μg / cm ² per 56.7μg / cm ^2, CMC per CNF, then it is preferably 566.7μg / cm ² per 566.7μg / cm ^2, CMC per CNF I understand.

1 heat fusion film 11 base material layer 12 sealant layer 2 solution

Claims (7)

In the sealant layer of a heat sealing film having a heat sealing property sealant layer,
After addition of a solution containing cellulose nanofibers, and a water-soluble polymer that is negatively charged when dissolved in water,
A method of fusing a heat fusion film, comprising fusing the sealant layer.   The heat according to claim 1, characterized in that the heat fusible films are fused by the sealant layer after adding the solution to the sealant layer of either or both of the heat fusible films. Fusion method of fusion film. Amount added of the cellulose nanofibers, by summing the mutually additional amount to both fused in part of the heat-fusible film, wherein the 28μg / cm ² or more and 1000 [mu] g / cm ² or less The fusion method of the heat fusion film according to claim 2. The addition amount of the water-soluble polymer is 28 μg / cm ² or more and 5400 μg / cm ² or less, which is the total of the addition amounts of the heat-fusion film to the mutually fused portions. The fusion | melting method of the heat-fusion film of Claim 2 or 3 to carry out.   The method for fusing a heat fusion film according to any one of claims 1 to 4, wherein the water-soluble polymer is carboxymethylcellulose.   The heat-sealable film according to any one of claims 1 to 5, wherein a heat-sealable film having one or more heat-sealable sealant layers is disposed so as to cover the article to be packaged. A packaging method comprising fusing the sealant layer by a method of fusing a film.   A package in which a heat fusion film having a heat fusion sealant layer covers one or more sheets by the sealant layer so as to cover the article to be packaged, and the fusion-bonded portion of the sealant layer A package comprising cellulose nanofibers and a water-soluble polymer that is negatively charged when dissolved in water.

Images