JP2000225670A - Heat sealing composite film and laminated material and paper container using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sealing film having alcoholic-drink-resistant aptitude and excellent in sealability in a paper container filled with a liquid and a laminate and a paper container using the same. SOLUTION: A composite film for HS is used in a laminated material 10 consisting of at least a surface resin layer 8, a base material 5, a physical property reinforcing layer 50 provided if desired and an HS layer. The composite film for HS is constituted by laminating a low-crystalline saturated polyester 2 and polyethylene 4 through a curable adhesive 3 from the contact side with content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite film for heat sealing (hereinafter, described as a composite film for HS) used as a component of a heat sealant layer (hereinafter, referred to as an HS layer) of a container. For composite film for HS which is excellent in processing suitability of film and laminated material, moldability (sealing property) of container, taste retention performance of contents (especially alcoholic beverage), and technology of laminated material and paper container using it. Belong.

[0002]

2. Description of the Related Art A paper container filled with a liquid as a content, particularly a chemical or a highly flavored food, must not leak liquid from a sealed container and must be permeable to vapor and flavor components (liquid sealing). Sex) Needless to say. And the thermoplastic resin used for the HS layer in contact with the contents of the container,
The flavor components must not be adsorbed or the decomposition products of the resin must not have any unpleasant taste or smell added to the contents. Furthermore,
Due to the permeation of oxygen in the air, the contents may be oxidized and adversely affected such as alteration and discoloration. Therefore, in order to preserve the contents for a long period of time, it is necessary that the above-mentioned paper container has not only the water vapor but also the infiltration and permeation of the filled flavor component and gas containing oxygen (airtightness). is there.

[0003] The sealing properties of paper containers are often due to defects in the sealing part due to heat sealing. For example, FIG. 6 is a perspective view showing a portion for confirming the sealing property of the paper container 20, and FIG. 7A is a step portion D of a WW portion sealing the top of FIG.
S, FIG. 7 (b) is the center seal portion CS of FIG. 6, FIG. 7 (c)
FIG. 7 is a schematic enlarged view showing a cross section B of the bottom seal portion in FIG. 6. The liquid-tightness and airtightness of the paper container 20 will be described by exemplifying the Goebel top type container shown in FIG. 6.
Are a step portion DS which is a seal end portion of the sticking plate, a center seal portion CS at the center of the gobel, and a bottom seal portion B. As shown in FIG.
In the cross section of S, there is a space X formed by the panels V2 and SV1. As shown in FIG. 7 (b), in the cross section of the center seal portion CS, the space portions Y are formed at the junctions of the folded portions SV1 and SV2 of the side panels of the panels V1 and V2. . Also, at the bottom, the folded portion SV of the side panel between the panels V1 and V2
If the sealing portion B at the confluence of SV1 and SV2 is not completely sealed, the stuffing will ooze out of the bottom space Z shown in FIG. 7 (c). Therefore, in the molding process of the paper container, the resin on the inner surface of the paper container laminated material is melted, and the space X,
Y and Z must be securely sealed.

[0004] In order to ensure the sealing in this manner, there is a method of heating and melting the resin of the HS layer used for molding the container and then heating and melting the resin to strengthen the heating and pressing conditions. However, in such a case, the resin of the HS layer is pushed away, the resin of the heat seal portion becomes thinner, the heat seal strength is reduced (root breaking phenomenon), and the resin is liable to be damaged at the time of distribution and causes liquid leakage. Become. When the heating conditions are increased, the HS layer in contact with the contents is oxidized and decomposed, and low-molecular-weight decomposition products generated at that time are transferred to the contents and may cause a deterioration in flavor. .
It is difficult to set the conditions for performing the box making, filling and sealing steps under such contradictory heat sealing conditions, and to maintain stable operation, and it is difficult to avoid instability of heat sealing, and to solve it Therefore, it was necessary to increase the thickness of the HS layer. Therefore, the structure of the laminate for obtaining a paper container having good heat sealability has been desired to have a wide range of working conditions, particularly a material capable of stably sealing even when the heat seal temperature is low.

[0005] The basic layer structure of a paper container used for liquid filling of the above-mentioned goebel top type or brick type is described as "Low density polyethylene (hereinafter referred to as LDPE: (surface resin layer) / (surface resin layer) / Paper (base material) / LDPE (HS
Layer)]. When strength or water vapor or gas barrier properties are required for the paper container, aluminum foil, a biaxially stretched polyethylene terephthalate film, a biaxially stretched nylon film, which is a film having a barrier property or strength between the paper and the HS layer. A reinforcing layer selected from aluminum-deposited plastic films, silicon oxide-deposited plastic films, and the like (various barrier properties and reinforcement of physical strength) was inserted.

[0006] There is also disclosed a technique using "low-crystalline linear saturated polyester" (hereinafter, referred to as linear polyester) in an HS layer in which flavor adsorption, which is a drawback of polyolefin, can be ignored. (Patent registration number 26192
For the physical property enhancement layer such as a barrier layer for preventing transmission of flavor, aluminum or a stretched or non-stretched film such as polyester or nylon on which metal or inorganic oxide is deposited is used as a component of the laminated material. The above-mentioned linear polyester has been used as the HS layer. The linear polyester used for the HS layer (the innermost layer of the container) can prevent the adsorption of flavor, which is a drawback of polyolefin (eg, polyethylene). However, in the case of an alcoholic beverage having a high concentration (25% or more), the adhesion between the barrier layer (the physical property enhancing layer) and the HS layer is reduced, and the sealing of the step portion in the above paper container becomes unstable, so that the seepage is infiltrated. There was a problem of leaking.

The HS layer made of a polyolefin resin has a problem that the flavor is impaired during storage by permeating or adsorbing organic compounds, particularly alcohols and esters, which are flavor elements of the contents. In addition, in the case of a beverage containing alcohol depending on the selection of the bonding method,
The peel strength between the HS layer and the barrier layer is reduced,
In addition, there has been a problem in that the strength of the container is reduced due to peeling, and the sealing property of the sealing portion of the paper container cannot be completely and stably maintained.

Hitherto, high-concentration alcoholic beverages such as whiskey, vodka, and white liquor have been used for alcoholic beverage paper containers having a linear polyester as an HS layer. As shown in FIG. 4 or FIG. 5, this laminated material includes a surface resin layer, paper (base material), an adhesive resin layer, an aluminum foil, a biaxially stretched polyester film (hereinafter, referred to as a polyester film), and an adhesive resin. Dry lamination using an adhesive or a laminated material such as a layer and a linear polyester, or a primer (in some cases, anchor coating,
Or AC)) and a sandwich lamination process using an adhesive resin layer.

However, a paper container formed from a laminated material obtained by sandwich lamination of an HS layer and a physical property enhancement layer has good sealing properties at the time of box making and filling, but is filled with an alcoholic beverage having a high concentration of 25% or more. If you store it,
There was a problem that peeling occurred in the sandwich lamination part. On the other hand, a paper container made of a laminated material in which the HS layer and the property enhancing layer are formed by dry lamination has little peeling at the bonding portion even when the above-described high-concentration alcoholic beverage is filled and stored. -There has been a problem that the sealing property at the time of filling becomes unstable and a liquid leakage product occurs.

[0010]

As an inner film of a paper container of a gobel-top type or a brick type, the above-mentioned step portion is filled with an alcoholic beverage having a high sealing stability of 25% or more, It is an object of the present invention to provide a composite film for HS that retains the strength of an initial bonded portion even when stored for a long period of time, and a laminated material and a paper container using the same.

[0011]

In order to solve the above-mentioned problems, the present invention provides a composite film for HS used for a laminate comprising at least a surface resin layer, a base material and a heat sealant layer. The composite film for HS is composed of at least two layers of a linear polyester and a linear polyethylene from the side that comes into contact with the contents, and the two layers are bonded to each other via a curable adhesive. The linear polyester has a glass transition point of 40 ° C.
The above is a composite film for HS. Further, the laminate is a laminate in which the base material is paper and a physical property enhancement layer is provided between the HS composite film and the base material. Further, at least the surface resin layer is polyethylene, a paper base material, an aluminum foil and a biaxially stretched polyester film as a physical property enhancement layer, and a composite film for HS used for a laminate comprising an HS layer, The composite film for HS is a laminated material composed of at least two layers of linear polyester and linear polyethylene from the side that comes into contact with the contents, and the two layers are adhered via a curable adhesive. And
It is a paper container using the laminated material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The composite film for HS of the present invention comprises:
As shown in FIG. 1, a laminated material 1 including a surface resin layer 8, a base material 5, a physical property enhancement layer 50 provided as required, and an HS layer
The composite film for HS 1 used for the HS
The composite film 1 for HS comprises at least two layers of a linear polyester 2 and a linear polyethylene 4 from the side in contact with the contents, and the two layers are bonded via a curable adhesive 3. Film 1. And, the glass transition point of the linear polyester is 40 ° C. or higher.
It is a composite film for S. Further, the laminated material 10 is a paper in which the base material is paper and the physical property enhancement layer 50 is provided between the layers of the composite film for HS.

A composite for HS used as a laminated material comprising a surface resin layer 8 made of polyethylene, a base material 5 made of paper, an aluminum foil 6 serving as a physical property enhancement layer 50, a biaxially stretched polyester film 7, and an HS layer. Film 1
A laminate in which the composite film for HS comprises at least two layers of a linear polyester 2 and a linear polyethylene 1 from the side that comes into contact with the contents, and the two layers are bonded via a curable adhesive 3 Material 10. A paper container 20 using the above-mentioned laminated material.

The composite film for HS of the present invention is a composite film obtained by laminating a linear polyester (HS surface) and a linear polyethylene via a curable adhesive. The linear polyester has a low crystalline glass transition point of 40 ° C. or higher formed from a polyhydric alcohol and a polyhydric fatty acid.
For example, polybasic acids such as adipic acid, azelaic acid, sebacic acid, isophthalic acid, terephthalic acid, and 1,4-butanediol, 1,6-hexanediol, ethylene glycol, tetramethylene glycol, trimethylolpropane, epoxy resin, polyethylene It is a linear polyester derived from a blend in which the glass transition point can be selected from glycol, polypropylene glycol, and the like.

The linear polyethylene, which is compounded with the linear polyester via the curable adhesive, flows to the space when the paper container is heat-sealed, and assists in completing the sealing. Further, it is preferable that the paper container 20 has physical properties to fill the gaps X, Y, and Z generated in the step seal portion DS, the center seal portion CS, and the bottom seal portion B of the paper container 20 shown in FIGS. Therefore, the HS layer is selected to have a low melting point, a large melt flow ratio, and a property that is easy to flow when heating the heat seal. And what has excellent heat fluidity and hot adhesiveness (hot tack), and can obtain strong adhesion with a linear polyester and a curable adhesive is preferable. Preferred are ethylene / α-olefin copolymers synthesized using a single-site catalyst, and ethylene / α-olefin copolymers composed of ethylene and polypropylene, butene-1, pentene-1, hexene1, etc., and other low or medium density Examples include polyethylene and mixtures thereof, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylate ester copolymer, and ionomer.

The polyolefin film constituting the composite film for HS can be prepared and supplied by a usual method using a circular die or a T die of single-layer or multilayer co-extrusion. It is preferable that the side to be bonded to the curable adhesive is subjected to a corona discharge treatment or the like to ensure affinity with the adhesive. In addition to the above-mentioned polyolefin being supplied in a separate step, for example, as shown in FIG. 3, it is also possible to form a polyolefin 4 by melt extrusion coating by providing a primer 36 on the polyester film 7. In this case, the side to be bonded to the linear polyester is subjected to corona discharge treatment so as to have an affinity for the curable adhesive.

Curable adhesives include esters having any of a hydroxyl group, an amino group, a carboxyl group, or the like, those obtained by curing an initial polymer of ether with polyisocyanate, polyether polyurethane polyisocyanate, and polyester polyurethane polyisocyanate. It is a reaction product of an isocyanate. The initial polymer is adipic acid, azelaic acid,
Oligomers derived from sebacic acid and 1,4-butanediol, 1,6-hexanediol, ethylene glycol, tetramethylene glycol, trimethylolpropane, epoxy resin, polypropylene glycol, polyether glycol, urethane-modified polyol, or vinyl chloride -A cured product of a vinyl acetate copolymer or the like and a polyisocyanate. And polyisocyanate is methylene bis (p-phenylene diisocyanate), hexamethylene diisocyanate, adduct of hexamethylene diisocyanate / hexanetriol, tolylene diisocyanate, adduct of tolylene diisocyanate / trimethylol propane,
1,5 naphthylene diisocyanate, thiodipropyl diisocyanate, ethylbenzene-2,4 diisocyanate, 2,4 tolylene diisocyanate, 44 '
It is composed of a curing agent appropriately selected from 4 '' triphenylmethane triisocyanate, tris (4-phenylisocyanate) thiosulfate, and the like.

The thickness of each layer forming the composite film for HS can be arbitrarily set. For example, linear polyester
20-80 μm, polyolefin 4 20-100 μm
Within the range, the content is selected according to the purpose of use, such as the density and the filling amount. The thickness ratio between the linear polyester and the polyolefin can be selected in the range of 1/5 to 5/1.

The composite film for HS of the present invention is obtained by laminating the above-mentioned linear polyester and polyolefin via a curable adhesive. The adhesive is dissolved in a solvent and applied to the linear polyester to dry-lamination with the polyolefin film, or laminated using a curable adhesive containing no solvent (also referred to as non-solami). Then, after lamination, by aging the adhesive at a temperature of 30 ° C. or higher, it is possible to form a curable adhesive that has preferably completed the reaction. And the amount of adhesive applied is 2
10 g / m ² (solid content), and the coating is performed by a method such as a usual gravure coat, gravure reverse coat, roll coat, reverse coat, bar coat, etc., depending on the viscosity and amount of the adhesive applied.

The base paper used in the laminate for a paper container of the present invention is a paperboard for an uncoated or lightly coated paper (coated paper having a coating amount of 12 g / m ² or less). For example, ivory,
Select from card paper, general manila balls, etc. in consideration of rigidity, strength and thickness (basis weight: g / m ² ). And preferably, a single-layer paper making or a binder using 15
It is of ^{0g / m 2 ~600g / m 2} .

The physical property enhancing layer of the present invention is a layer which provides a water vapor and / or gas barrier property for preventing deterioration of the filled contents when a laminated material for a paper container is formed. For example, there is a plastic film formed by elongating or non-stretching a thermoplastic resin and formed by evaporating silicon oxide or metallic aluminum, or a plastic film coated with a layer of polyvinyl alcohol or vinylidene chloride. Also, there are saponified ethylene / vinyl acetate copolymer, acrylonitrile, polyvinyl alcohol, vinylidene chloride, nylon film and metal aluminum foil. Preferably, it is 7 to 15 μm having excellent water vapor and gas barrier properties.
Metal aluminum foil.

In order to impart strength to the paper container during transportation or to withstand external impact, it is preferable to use a stretched film such as polypropylene in addition to the above-mentioned polyester and nylon. Barrier properties and strength can be added to the paper container laminate.

The lamination of the heat-sealing multi-layer film constituting the paper container lamination material and the base paper is performed by laminating the bonding layer of the heat-sealing multi-layer film and the paper with an adhesive resin layer (usually LDPE). And laminated by sandwich lamination. When the bonding layer is made of a material other than a polyethylene resin, such as a polyester film, a nylon film, or an aluminum foil, a primer is provided on the polyester film or aluminum to form an adhesive resin layer (LDPE).
To be laminated. The thickness of the adhesive resin layer used for sandwich lamination for laminating the multilayer film for heat sealing and paper is 15 to 40 μm. The thickness of the adhesive resin layer is not limited to the above numerical value, but can be arbitrarily set according to the size of the paper container.

When the side of the barrier layer is bonded to a resin having a carbonyl group such as nylon, saponified ethylene / vinyl acetate copolymer or aluminum foil, it is necessary to provide a primer directly on the side of the barrier layer without using a primer. A laminated material for a paper container can also be formed by sandwich lamination with an adhesive layer of an HS composite film using an adhesive resin layer such as an acid copolymer, an ethylene / acrylate copolymer, or an ionomer. .

The lamination of the physical property enhancement layer is performed by dry lamination using an adhesive applied to ordinary lamination of a plastic film, or, if necessary, by sandwich lamination via a primer and a thermoplastic adhesive resin layer. Can be configured.

The laminate of paper and aluminum foil is made of ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic ester copolymer, ionomer, etc., which have excellent peel strength from the aluminum surface. It is melt-extruded and coated as an adhesive resin layer and laminated by sandwich lamination.

The laminated material for a paper container using the multilayer film for heat sealing of the present invention is used as the innermost film of the above-mentioned goebel top type or brick type paper container. The present invention is also applicable to containers containing liquids or viscous materials, such as pouches, inner bags of bag-in-boxes, laminate tubes, paper cups, or round containers in which paper is laminated.

The surface resin layer of the present invention can be provided with a thickness of 15 to 40 μm by melting and extruding a usual thermoplastic resin used for a liquid container. For example,
It can be selected from LDPE, medium density polyethylene, linear polyester and the like. It is preferable to add a lubricant or an antistatic agent in order to improve the processability when producing the paper container.

[0029]

EXAMPLES Samples of Examples and Comparative Examples were prepared from a laminated material for a paper container of a gobel top type with the following configuration. (Example 1) As shown in FIG. 2, the basis weight was 300 g / m
² (paper 5) was melt-extruded and coated with LDPE having a density of 0.923 g / cm ³ and a melt index of 4.5 g / 10 min at a thickness of 20 μm to form (surface resin layer 8). Then, one side of the polyester film 7 having a thickness of 12 μm was coated with a urethane isocyanate-based adhesive 26 at 3 g / m ^2, and was dry-laminated with the aluminum foil 6 to form a barrier layer 51 (a property enhancing layer).
In addition, a linear polyester having a glass transition point of 81 ° C. (PET)
-G6763, manufactured by Eastman Kodak Company, trade name), linear polyester having a glass transition point of -20 ° C (byron GM-900, manufactured by Toyobo Co., Ltd., trade name), and PET-G6763 each having a thickness of 20 µm. A linear polyester film 2 was sequentially formed by a coextrusion method. Then, a 30 μm-thick linear polyethylene film 4 was provided with a 3 g / m ² urethane isocyanate-based adhesive (curable adhesive 3) and dry-laminated to form a composite film 1 for HS. Next, an isocyanate-based primer 36 was provided on the polyester film 7 of the barrier layer 51, and sandwich lamination with the composite film 1 for HS was performed using the LDPE (adhesive resin layer 17). Further, a copolymer of ethylene and methacrylic acid (adhesive resin layer 16, hereinafter referred to as EMMA) is melted on the side of the base material 5 provided with the surface resin layer 8 and the aluminum foil 6. The laminate was extruded and sandwich-laminated to form a laminate 10 of Example 1 of the present invention.

Example 2 As shown in FIG. 3, LDPE was coated on paper (base material 5) having a basis weight of 300 g / m ² to a thickness of 20 g / m ^2.
It was melt-extruded and coated at μm to form (surface resin layer 8). The urethane isocyanate-based adhesive 26 was coated on one side of the polyester film 7 having a thickness of 12 μm with 3 g /
m ² coating and dry lamination with the aluminum foil 6 to form a barrier layer 51. Further, the side of the substrate 5 provided with the surface resin layer 8 and the aluminum foil 6 were
MA (adhesive resin layer 16) was melt extruded and laminated by sandwich lamination. Then, a urethane-based primer 36 was provided on the polyester film 7, and the linear polyethylene was extrusion-coated with a thickness of 20 μm, and a polyolefin layer 41 was formed by corona discharge treatment on the side of the HS layer and the dry lamination. Next, the linear polyester 2 prepared in Example 1 and the urethane-based curable adhesive 3 were provided and laminated, and Example 2 of the present invention was performed.
Was produced.

(Comparative Example 1) As shown in FIG. 4, in the same manner as in Example 1, a paper (base material 5) was coated with LDPE having a thickness of 20 mm.
It was melt-extruded and coated at μm to form (surface resin layer 8). Then, 3 g of the urethane isocyanate-based adhesive 26 was applied to one side of the polyester film 7 having a thickness of 12 μm.
/ M ² and dry lamination with the aluminum foil 6 to form a barrier layer 51. Also, a 30 μm thick linear polyester 2 having a glass transition point of 40 ° C. or more and an adhesive resin admer having a thickness of 10 μm (Mitsui Chemicals, Inc.)
Co-extrusion H formed into a film by co-extrusion
An S layer 15 was formed. Next, a urethane-based primer 36 is provided on the polyester film 7 side of the barrier layer 51, and a 20 μm-thick linear polyethylene is melt-extruded to form an adhesive resin layer 17 by coating.
5 and sandwich lamination. Then, the paper (base material 5) provided with the LDPE and the aluminum foil 6 were sandwiched and laminated via an EMMA (adhesive resin layer 16) having a thickness of 20 μm to form a laminated material 11 of Comparative Example 1. .

Comparative Example 2 As shown in FIG. 5, in the same manner as in Example 1, paper (base material 5)
It was melt-extruded and coated at μm to form (surface resin layer 8). Then, 3 g of the urethane isocyanate-based adhesive 26 was applied to one side of the polyester film 7 having a thickness of 12 μm.
/ M ² and dry lamination with the aluminum foil 6 to form a barrier layer 51. Next, the barrier layer 5
The urethane isocyanate-based adhesive 27 was provided at 3 g / m ² on the side of the polyester film 7 and the linear polyester 2 was laminated. Further, the paper 5 and the aluminum foil 6 of the barrier layer 51 are combined with a 20 μm thick EMM.
A was melt extruded and sandwich-laminated to form a laminate 12 of Comparative Example 2.

Next, in the process of preparing a 1.8-liter gobel-top type paper container using each of the paper container laminates of Examples and Comparative Examples, the processability of the paper container including slippage of the laminated material was evaluated. And 40 using a liquid filling machine
% Of a colored ethanol aqueous solution, and the results of the following evaluations are shown in Table 1.

(Sealability) The state of leakage of the gap (Z) of the center seal portion in the bottom seal portion of the goebel top type paper container at 300 ° C. under the condition of 300 ° C. in a liquid container packing container of 600 bottles / hour. Visually evaluate at the position of 6 (c). Evaluation criteria: The permeation position of ethanol in the center seal portion 24 hours after filling is visually evaluated. B1: ○ B2: △ B3: × (Ethanol resistance)
After storing at 0 ° C. for 120 days, the peel strength between the linear polyester 2 and the polyolefin 4 of the composite film for HS, or the polyester 2 of the comparative example and the admer 36 or the stretched film 7 was measured in accordance with JIS K 6854 (peel adhesion of adhesive). 15mm according to the strength test method T-type peeling test)
Measured under the conditions of width and tensile speed of 50 mm / min, g / 1
Display in 5 mm width.

[0035]

[Table 1]

[0036]

The paper container made of a laminated material in which the HS layer on the inner surface of the paper container is a composite film for HS in which a linear polyester and a polyolefin are laminated via a curable adhesive, has a high concentration of ethanol as a content. Even if the beverage is filled and stored, no decrease in peel strength is observed. In addition, the polyolefin compounded with the curable adhesive has an effect of filling the space between the seal portions, and has an effect of forming a paper container having excellent sealing properties without oozing of the contents.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a composite film for HS and a laminated material of the present invention.

FIG. 2 is a schematic sectional view of a paper container laminate of the present invention.

FIG. 3 is a schematic cross-sectional view of a laminated material for a paper container having another configuration of the present invention.

FIG. 4 is a schematic cross-sectional view of a conventional laminated material for a chemical resistant paper container.

FIG. 5 is a schematic cross-sectional view showing another configuration of a conventional laminate for a chemical-resistant paper container.

FIG. 6 (a) is a perspective view showing an example of the paper container of the present invention. (b) is a schematic plan view showing the upper surface of the top seal portion. (c) A diagram for evaluating the sealing performance of the bottom seal portion.

FIG. 7 is an enlarged cross-sectional view of a seal portion for explaining a space portion. (a) It is an enlarged view of a step seal part. FIG. 3B is an enlarged cross-sectional view of a center seal portion. FIG. 3C is an enlarged cross-sectional view of a bottom seal portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Composite film for HS 2 Linear polyester 3 Curable adhesive 4, 41 Polyolefin 5 Base material 6 Aluminum foil 7 Polyester film 8 Surface resin layer 10, 11, 12 Laminated material 15 Co-extruded HS layer 16, 17 Adhesive resin layer 20 Paper container 26, 27 Adhesive 35 Admer 36 Primer 50 Physical property enhancement layer 51 Barrier layer B Bottom seal portion B1, B2, B3 Exudation position of bottom seal portion DS Step seal portion CS Center seal portion X Void formed in step seal portion Y Void created in center seal part Z Void created in bottom seal part

 ──────────────────────────────────────────────────の Continuing on the front page F term (reference) 3E060 AA05 AB04 BC01 BC04 DA30 EA03 EA20 4F100 AB10E AB33E AK01A AK04A AK06 AK41D AK41E AK51G AK63C AK70 AR00E AT00B BA02 BA04 BA05 BA07 BA10A BA10D CB02J06 J05 J10 JBJBJJB10E JL12D YY00D

Claims (5)

[Claims] 1. A composite film for a heat sealant layer used for a laminate comprising at least a surface resin layer, a substrate and a heat sealant layer, wherein the composite film for a heat sealant layer is in contact with the contents. A composite film for heat sealing, comprising at least two layers of a low-crystalline linear saturated polyester and a linear polyethylene, wherein the two layers are bonded via a curable adhesive. 2. The heat-sealing composite film according to claim 1, wherein the low-crystalline linear saturated polyester has a glass transition point of 40 ° C. or higher. 3. The laminated material according to claim 1, wherein the base material is paper, and the laminated material is a laminated sheet provided with a physical property enhancement layer between the heat-sealing composite film. 4. A composite film for a heat sealant layer used for a laminate comprising at least a surface resin layer made of polyethylene, a paper base material, an aluminum foil and a biaxially stretched polyester film as physical property reinforcing layers, and a heat sealant layer. Wherein the heat sealant layer composite film comprises at least two layers of a low-crystalline linear saturated polyester and a linear polyethylene from the side that comes into contact with the contents, and a curable adhesive is provided between the two layers. A laminated material, wherein the laminated material is adhered through a hole. 5. A paper container using the laminated material according to claim 1.