WO2024034532A1

WO2024034532A1 - Packaging bag and package

Info

Publication number: WO2024034532A1
Application number: PCT/JP2023/028535
Authority: WO
Inventors: 恵介山口; 和慶岡田; 雅文堀内
Original assignee: Ｔｏｐｐａｎホールディングス株式会社
Priority date: 2022-08-09
Filing date: 2023-08-04
Publication date: 2024-02-15

Abstract

Provided is a packaging bag composed of one or more laminates 10 and having a housing part, wherein: the laminates 10 each have a sealant layer 15, an adhesive layer 14, an electrostatic ink layer 13, a primer layer 23, and a base material 11 in this order from the housing part side; the adhesive layer 14 contains an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, a cured product thereof, or a mixture thereof; and the ratio of the thickness of the adhesive layer 14 to the thickness of the electrostatic ink layer 13 is 0.15-5.

Description

Packaging bags and packages

The present disclosure relates to a packaging bag and a packaging body.

BACKGROUND ART Packaging bags are known that store beverages, foodstuffs, etc. in a hermetically sealed manner. As the packaging bag, a package using a thin film or sheet is used. Various information such as the product, brand, manufacturer, etc. is printed on such packaging bags. As a means for such printing, a digital printing machine using an electrostatic ink composition is known.

For example, in Patent Document 1, a primer resin is applied to a first flexible base material such as a PET film to obtain a coated surface, and a digital printing machine (manufactured by HP, Indigo 20000 digital printer for labels and packages) is applied to the coated surface. It has been proposed to carry out electrostatic printing using a printing press) and to apply a crosslinking composition. It is known that laminates containing such electrostatic printing ink compositions have reduced adhesive strength. Therefore, in Patent Document 2, a cured product of polyol, polyisocyanate, and epoxy compound is bonded together to form a laminate that can maintain sufficiently high adhesive strength between each layer even under high-temperature hydrothermal conditions such as retort treatment. It is proposed to have layers.

In recent years, in addition to retort processing, packages that can be heated directly in a microwave oven are also on the market. In order to avoid bursting in a microwave oven, it is being considered for such a package to adopt a specific sealing structure that allows communication between the container and the outside when the pressure in the container increases. (For example, Patent Document 3).

Special table 2018-530478 publication International Publication No. 2021/024981 JP 2021-4049 Publication

When the package is heated, the internal pressure of the package increases and water vapor may be generated. The water vapor is not only generated from the storage section within the storage section, but also fills the heating chamber. Therefore, the packaging bag constituting the package is exposed to high-temperature water vapor. For this reason, packaging bags that can be used for heated packaging bodies are required to have durability against high-temperature water vapor.

Therefore, the present disclosure provides a packaging bag that has excellent durability even when heated while sufficiently ensuring a high degree of design freedom through electrostatic printing, and a packaging body equipped with such a packaging bag. The purpose is to provide

One aspect of the present disclosure is a packaging bag that is composed of one or more laminates and has a storage section, wherein the laminate includes, from the storage section side, a sealant layer, an adhesive layer, an electrostatic ink layer, and a storage section. , a primer layer and a base material in this order, the adhesive layer containing an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, a cured product thereof, or a mixture thereof; A packaging bag is provided in which the ratio of the thickness of the adhesive layer to the thickness of the ink layer is 0.15 to 5.

The packaging bag has an electrostatic ink layer and an adhesive layer containing an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, a cured product thereof, or a mixture thereof. This adhesive layer maintains the cohesive force of the electrostatic ink layer even when heated and comes into contact with high-temperature water vapor, and can maintain sufficiently high adhesive strength. Because the thickness ratio between the adhesive layer and the electrostatic ink layer is within a predetermined range, even though the electrostatic ink layer is present, the pressure inside the container increases and it does not come into contact with high-temperature water vapor. , interlayer peeling can be sufficiently suppressed. For this reason, it has excellent durability even when heated while sufficiently ensuring a high degree of design freedom through electrostatic printing.

One aspect of the present disclosure provides a package that includes the above-mentioned packaging bag and an item accommodated in a storage section of the packaging bag.

Since the above-mentioned packaging body includes the above-mentioned packaging bag, it has excellent durability even when heated while sufficiently ensuring a high degree of design freedom through electrostatic printing.

It is possible to provide a packaging bag that has excellent durability even when heated while sufficiently ensuring a high degree of design freedom through electrostatic printing, and a packaging body equipped with such a packaging bag. .

It is a sectional view along the lamination direction (thickness direction) of an example of a laminate with which a packaging bag is equipped. It is a sectional view along the lamination direction (thickness direction) of the laminated body of another example with which a packaging bag is equipped. It is a figure showing a packaging bag and a package concerning one embodiment. FIG. 4 is a diagram of a packaging bag used for producing the packaging bag and package of FIG. 3; (A) and (B) are diagrams showing an example of a steam venting section. It is a figure which shows the packaging bag and package body based on another embodiment. It is a figure which shows the packaging bag and packaging body based on yet another embodiment. FIG. 8 is a side view of the packaging bag and packaging body of FIG. 7; It is a figure which shows the packaging bag and packaging body based on yet another embodiment. 11 is a diagram of a packaging bag used for producing the packaging bag and package of FIG. 10. FIG. FIG. 11 is an enlarged view of the steam venting section and its vicinity in the packaging bag of FIGS. 9 and 10. FIG. FIG. 11 is an enlarged view of the steam venting section and its vicinity in the packaging bag of FIGS. 9 and 10. FIG. (A) and (B) are diagrams for explaining heat treatment before measuring peel adhesion strength. It is a photograph showing an example of delamination.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In the description, the same reference numerals will be used for the same elements or elements having the same function, and redundant description will be omitted in some cases. Moreover, the positional relationships such as up, down, left, and right are based on the positional relationships based on the directions of the symbols shown in the drawings, unless otherwise specified. The dimensional ratio of each element is not limited to the illustrated ratio.

A packaging bag according to one embodiment is a packaging bag that is composed of one or more laminates and has a storage section, and the laminate includes, from the storage section side, a sealant layer, an adhesive layer, an electrostatic ink layer, and a storage section. , a primer layer and a base material in this order. The packaging bag may be a packaging bag for heating in a microwave oven. However, the packaging bag is not limited to one for heating in a microwave oven.

The laminate forming the packaging bag may have a cross-sectional structure as shown in FIG. 1 or 2, for example. The laminate 10 in FIG. 1 includes a sealant layer 15, an adhesive layer 14, an electrostatic ink layer 13, a primer layer 12, and a base material 11 in this order from the accommodating part side.

The base material 11 may have a flexible base material. The flexible substrate may include, for example, one or both of a metal foil, such as an aluminum foil, and a thermoplastic polymer film. Flexible substrates include biaxially oriented polypropylene (BOPP), polyethylene terephthalate (PET), oriented polyamide (OPA) such as nylon, unoriented polypropylene (CPP), linear low density polyethylene (LLDPE), and low Examples include films of high density polyethylene (LDPE).

The base material 11 (base film) may be, for example, a vapor deposited film (transparent vapor deposited film) in which a barrier layer (deposited layer) is formed on a resin layer such as a PET film. By having the barrier layer closer to the adhesive layer 14 than the resin layer, the base material 11 suppresses exposure of the electrostatic ink layer 13 to high-temperature water vapor, further improving the durability of the laminate 10. be able to. Moreover, heating in a microwave oven can be performed smoothly. Examples of barrier layers include metal foils, vapor-deposited layers of metals (eg, aluminum) or metal oxides (eg, silica or alumina), and the like. The thickness of the base material 11 may be 7 to 150 μm, 10 to 100 μm, or 12 to 80 μm. A specific example of a transparent vapor-deposited film is a transparent vapor-deposited PET film in which a transparent vapor-deposited layer is formed on a PET film. Base material 11 may be a barrier nylon film.

Primer layer 12 may contain resin. Examples of the resin include polyvinyl alcohol resin, cellulose resin, polyester, polyamine, polyethyleneimine resin, polyamide resin, polyurethane, polyacrylic polymer hydroxyl-containing resin, carboxyl group-containing resin, and amine polymer. By having the primer layer 12, printing of the electrostatic ink composition using a digital printing machine can be performed smoothly. Furthermore, the adhesion of the electrostatic ink layer 13 to the primer layer 12 can be improved. The coating amount of the resin constituting the primer layer 12 may be, for example, 0.01 to 1.5 g/m ² or 0.05 to 1.0 g/m ² .

The electrostatic ink layer 13 may be composed of an electrostatic ink composition. The electrostatic ink layer 13 is provided by electrostatic printing using a digital printing machine. The electrostatic ink layer 13 may have a single color, or may be configured by laminating a plurality of electrostatic ink compositions having different colors. The electrostatic ink layer 13 may be in direct contact with the adhesive layer 14.

The thickness (TI) of the electrostatic ink layer 13 may be 6 μm or less, 5 μm or less, or 1 to 5 μm. By setting the thickness (TI) of the electrostatic ink layer 13 to be less than or equal to the above upper limit value, it is possible to sufficiently suppress interlayer delamination of the laminate 10 even when the pressure inside the storage section increases and comes into contact with high-temperature water vapor. . By setting the thickness (TI) of the electrostatic ink layer 13 to be equal to or greater than the above lower limit, the degree of freedom in design by electrostatic printing can be sufficiently increased.

The thickness of the electrostatic ink layer 13 and each layer other than the electrostatic ink layer 13 in the present disclosure can be measured by observing the cross section of the laminate 10 with a scanning electron microscope (SEM). The thickness (TI) of the electrostatic ink layer 13 in the laminate 10 does not have to be constant.

The adhesive layer 14 may be composed of an adhesive composition, a cured product thereof, or a mixture thereof. The adhesive composition contains a polyol, a polyisocyanate, and an epoxy compound. At least a portion of these three components (polyol, polyisocyanate, and epoxy compound) may react with each other and be cured to form a cured product. The cured product may contain polyurethane. The adhesive layer 14 containing the above three components and the electrostatic ink layer 13 are in direct contact. The epoxy compound contained in the adhesive layer 14 and the ink composition contained in the electrostatic ink layer 13 crosslink with each other, thereby sufficiently increasing the adhesive strength between the adhesive layer 14 and the electrostatic ink layer 13. Can be done.

The polyol has, for example, a number average molecular weight of 400 or more and has two or more hydroxyl groups in one molecule. Polyisocyanate has two or more isocyanate groups in one molecule. The polyol and polyisocyanate may react as a base agent and a curing agent, respectively, to produce polyurethane (polyurethane adhesive). The polyol may have a number average molecular weight of, for example, 10,000 or less.

The polyol may contain at least one selected from the group consisting of polyester polyols and polyether polyols. Among these, from the viewpoint of sufficiently increasing the adhesive strength of the adhesive layer 14 in a high-temperature environment, the polyol may include a polyester polyol or an aliphatic polyester polyol.

The polyester polyol can be obtained, for example, by a condensation reaction or transesterification reaction between a polyhydric alcohol and a polybasic acid, its alkyl ester, its acid anhydride, or its acid halide. Examples of the polyhydric alcohol include low molecular weight diols, low molecular weight triols, and low molecular weight polyols having four or more hydroxyl groups.

Examples of low molecular weight diols include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, and 3-methyl- 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 2,2-diethyl-1,3-propanediol, 3,3-dimethylol Examples include heptane, 2-ethyl-2-butyl-1,3-propanediol, and the like.

Examples of low molecular weight triols include glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, and trimethylolethane. , trimethylolpropane, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-(hydroxymethyl)pentane, and 2,2-bis(hydroxymethyl)-3-butanol etc.

Examples of low molecular weight polyols having four or more hydroxyl groups include tetramethylolmethane, pentaerythritol, dipentaerythritol, D-sorbitol, xylitol, D-mannitol, and D-mannitol.

Examples of alkyl esters of polybasic acids include methyl esters and ethyl esters of polybasic acids. Examples of acid anhydrides include acid anhydrides derived from polybasic acids. Examples include oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, 2-alkyl (carbon number 12 to 18) succinic anhydride, tetrahydrophthalic anhydride, and trimellitic anhydride.

Examples of acid halides include acid halides derived from the polybasic acids mentioned above. Examples include oxalic acid dichloride, adipic acid dichloride, sebacyl dichloride, and the like.

The polyether polyol may be a polyalkylene oxide. For example, it may be obtained by addition reaction of alkylene oxide such as ethylene oxide and/or propylene oxide using a low molecular weight polyol as an initiator. Specific examples include polyethylene glycol, polypropylene glycol, and polyethylene polypropylene glycol (random or block copolymer). Other examples include polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran.

Examples of the polyisocyanate include polyisocyanate monomers, polyisocyanate derivatives, and isocyanate group-terminated prepolymers. The adhesive composition may contain multiple types of polyisocyanates that are different from each other. The molar ratio (NCO/OH) of the isocyanate groups contained in the polyisocyanate to the hydroxyl groups of the polyol may be from 0.5 to 10, and may be from 0.8 to 8.4. Such an adhesive composition can form a cured product that has high adhesive strength and excellent flexibility.

Examples of the polyisocyanate monomer include aliphatic polyisocyanates, aromatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates.

Examples of aliphatic polyisocyanates include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), 1 , 5-pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl capate, etc. can be mentioned.

Examples of the aromatic aliphatic polyisocyanate include xylylene diisocyanate derivatives. Examples of xylylene diisocyanate derivatives include xylylene diisocyanate (1,3-xylylene diisocyanate or 1,4-xylylene diisocyanate) (XDI), tetramethylxylylene diisocyanate (1,3-tetramethylxylylene diisocyanate) or 1,4-tetramethylxylylene diisocyanate) (TMXDI), ω,ω'-diisocyanate-1,4-diethylbenzene, and a polyol of xylylene diisocyanate obtained by reaction of xylylene diisocyanate and trimethylolpropane. Examples include modified forms.

The content of the xylylene diisocyanate derivative relative to the entire polyisocyanate may be 10% by mass or more, 20% by mass or more, 30% by mass or more from the viewpoint of improving reactivity with the main agent (for example, polyol). It may be 40% by mass or more. By setting the content to 30% by mass or more, the reactivity can be further increased.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3 , 5,5-trimethylcyclohexyl isocyanate (isophorodiisocyanate) (IPDI), methylcyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate), and norbornane diisocyanate (NBDI). It will be done.

Examples of polyisocyanate derivatives include multimers, allophanate modified products, polyol modified products, polyol modified products produced by reaction of monomers with alcohols, biuret modified products, and urea modified products of the above-mentioned polyisocyanate monomers. , oxadiazinetrione modified products, carbodiimide modified products, uretdione modified products, uretonimine modified products, and the like.

The isocyanate group-terminated prepolymer is a urethane prepolymer having at least two isocyanate groups at the molecular ends. The urethane prepolymer can be obtained by subjecting at least one member selected from the group consisting of a polyisocyanate monomer, a polyisocyanate derivative, and an isocyanate group-terminated prepolymer to a urethane reaction with a polyol. At this time, the molar ratio (NCO/OH) of the isocyanate groups contained in the polyisocyanate to the hydroxyl groups of the polyol is 0.5 or more, 0.6 or more, 0.8 or more, 1 or more, or 1.5 or more. good. The molar ratio (NCO/OH) may be 10 or less, 5 or less, 4 or less, or 3 or less. Examples of numerical ranges for the molar ratio (NCO/OH) include 0.5-10, 0.5-5, 0.8-4, and 0.6-3.

The epoxy compound may be a compound having one or more epoxy groups in one molecule. From the viewpoint of maintaining sufficiently high peel adhesion strength between the adhesive layer 14 and the electrostatic ink layer 13 when in contact with high-temperature water vapor, it may have epoxy groups at both ends. Examples of the epoxy compound include glycidyl ether type epoxy compounds, glycidyl amine type epoxy compounds, glycidyl ester type epoxy compounds, and alicyclic epoxy compounds (cycloaliphatic epoxy compounds).

The molecular weight of the epoxy compound may be 500 or less, 450 or less, or 400 or less. Such an epoxy compound can be sufficiently penetrated into the electrostatic ink composition constituting the electrostatic ink layer 13. The lower limit of the molecular weight of the epoxy compound may be, for example, 98.

Examples of the alicyclic epoxy compound include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate.

Examples of monofunctional alicyclic epoxy compounds having one epoxy group in one molecule include 3,4 epoxycyclohexylmethyl methacrylate and 1,2-epoxy-4-vinylcyclohexane. Examples of bifunctional epoxy compounds having two epoxy groups in one molecule include 3',4'-epoxycyclohexylmethyl-3,4 epoxycyclohexane carboxylate, bis(3,4-epoxycyclohexylmethyl) adipate, and , 4-vinylcyclohexene dioxide and the like. In addition, as an epoxy compound having one or more epoxy groups in one molecule, 1,2-epoxy-4-2,2-bis(hydroxymethyl)-1-butanol represented by the following general formula (I) (2-oxiranyl)cyclohexane adducts are mentioned.

In the above general formula (I), R represents a monovalent functional group, and n may be an integer of 1 to 4.

The epoxy compound may include a difunctional alicyclic epoxy compound. By being bifunctional, it is possible to increase the number of crosslinking points with the electrostatic ink composition and the primer resin, thereby promoting the curing reaction of the adhesive and making it easier to cure. Further, by being alicyclic, reaction with polyisocyanate can be suppressed due to steric hindrance. Therefore, it can be stably cured, and the adhesion between the electrostatic ink layer 13 and the adhesive layer 14 can be made sufficiently excellent.

In the adhesive composition, the content of the epoxy compound relative to 100 parts by mass of polyol may be 3 to 25 parts by mass, and 6 to 25 parts by mass, from the viewpoint of achieving both high adhesive strength and excellent shear suppressing force. The amount may be 8 to 20 parts by mass. When the content of the epoxy compound becomes too large, the excellent shear restraining force tends to be impaired. That is, when the adhesive layer 14 is formed, the adhesive surface may shift or the adhesive composition may protrude. If the amount of the epoxy compound is too small, the peel adhesion strength when in contact with high-temperature water vapor tends to decrease.

In the adhesive composition, the content of polyisocyanate based on 100 parts by mass of polyol may be 10 to 50 parts by mass, and 15 to 50 parts by mass, from the viewpoint of maintaining sufficiently high peel adhesive strength when in contact with high-temperature steam. It may be 35 parts by weight, or 20 to 30 parts by weight.

The molar ratio of the epoxy group contained in the epoxy compound to the isocyanate group contained in the polyisocyanate may be 0.5 to 10, may be 1.5 to 9, and may be 2.0 to 6.5. Good too. This makes it possible to maintain a sufficiently high peel adhesion strength when in contact with high-temperature water vapor.

The adhesive composition constituting the adhesive layer 14 may contain optional components such as additives in addition to the above-mentioned components. Examples of additives include antioxidants, ultraviolet absorbers, light stabilizers, fillers, silane coupling agents, epoxy resins, catalysts, coating improvers, leveling agents, nucleating agents, lubricants, mold release agents, Examples include antifoaming agents, plasticizers, surfactants, pigments, dyes, organic fine particles, inorganic fine particles, fungicides, and flame retardants. The adhesive composition may contain a solvent such as an organic solvent.

The thickness (TA) of the adhesive layer 14 may be 1 to 12 μm, 1.3 to 8 μm, or 1.5 to 5 μm. By setting the thickness (TA) of the adhesive layer 14 to be equal to or greater than the above lower limit value, it is possible to sufficiently suppress interlayer peeling of the laminate 10 even if the pressure inside the accommodating portion increases and comes into contact with high-temperature water vapor. When the thickness (TA) of the adhesive layer 14 is less than or equal to the above upper limit value, the manufacturing cost of the packaging bag can be reduced and the productivity of the packaging bag can be increased.

The total thickness (TI+TA) of the electrostatic ink layer 13 and the adhesive layer 14 may be 2 to 20 μm, 3 to 10 μm, or 4 to 8 μm. By having the total thickness equal to or greater than the above lower limit value, the degree of freedom in design using electrostatic printing is sufficiently increased, and even if the pressure inside the storage part increases and comes into contact with high-temperature water vapor, interlayer delamination of the laminate 10 is prevented. can be sufficiently suppressed. When the total thickness is less than or equal to the above upper limit value, the laminate 10 can be easily torn, and the package can be opened smoothly.

As the sealant layer 15, polyester films such as unoriented polypropylene film (CPP film), linear low density polyethylene film (LLDPE film), biaxially oriented polypropylene film (OPP film), polybutylene terephthalate (PBT), biaxial Examples include stretched nylon film. Heat resistance can be further improved by using polybutylene terephthalate. The thickness of the sealant layer 15 may be 10 to 150 μm, 20 to 100 μm, or 30 to 80 μm.

The ratio of the thickness (TA) of the adhesive layer 14 to the thickness (TI) of the electrostatic ink layer 13 may be 0.15 to 5. The thickness ratio may be 0.2-4, 0.25-3, or 0.3-2. When the thickness ratio is equal to or greater than the lower limit, delamination can be sufficiently suppressed even when the pressure inside the housing part of the packaging bag increases and comes into contact with high-temperature water vapor. By setting the thickness ratio to be less than or equal to the upper limit value, it is possible to sufficiently ensure a high degree of freedom in design by electrostatic printing. Moreover, it is possible to suppress an increase in the manufacturing cost of the packaging bag and a decrease in productivity due to the excessive thickness of the adhesive layer 14.

The laminate 10a in FIG. 2 includes, from the side of the storage part of the packaging bag, a sealant layer 15, a second adhesive layer 17, a resin layer 16, an adhesive layer 14 (first adhesive layer), an electrostatic ink layer 13, and a primer. It has the layer 12 and the base material 11 in this order. That is, this differs from the laminate 10 of FIG. 1 in that it has a second adhesive layer 17 and a resin layer 16 between the sealant layer 15 and the adhesive layer 14. Each layer other than the second adhesive layer 17 and the resin layer 16 in the laminate 10a may be the same as the laminate 10.

The second adhesive layer 17 is not particularly limited, and for example, a normal urethane resin adhesive or the same adhesive as the adhesive layer 14 may be used. Examples of the resin layer 16 include a nylon film and a polyester film such as a PET film. The laminate forming the packaging bag is not limited to the laminate structure shown in FIGS. 1 and 2, and may have any resin layer and adhesive layer.

The peel adhesion strength Sb of the

laminates

10, 10a at room temperature (20° C.) may be 1.5 [N/15 mm] or more, may be 2.0 [N/15 mm] or more, and may be 2.3 It may be [N/15mm] or more. Such a laminate 10, 10a can sufficiently suppress interlayer peeling at room temperature (20° C.). The peel adhesion strength Sb can be measured in accordance with JIS K 6854-1:1999 by cutting the

laminates

10 and 10a into 15 mm width pieces. After separating the layers at the ends of the measurement sample, measurement can be performed using a tensile tester at an angle of 90°, a tensile speed of 300 mm/min, and room temperature (20° C.).

S1 is the peel adhesion strength after the surface 10A of the laminate 10, 10a on the base material 11 side is exposed to an atmosphere containing water vapor, and S1 is the peel adhesion strength after the surface 10B of the laminate 10 on the sealant layer 15 side is exposed to the atmosphere. When the peel adhesion strength of S2 is S2, S2/S1 may be 0.6 to 1.6, 0.7 to 1.4, or 0.8 to 1.2. It's okay. Peel adhesion strengths S1 and S2 are peel adhesion strengths measured at room temperature (20° C.) after exposing the

surfaces

10A and 10B to an atmosphere containing water vapor under the same conditions, respectively. The peel adhesion strengths S1 and S2 can be measured by the same measuring method as the peel adhesion strength Sb.

The

laminates

10 and 10a do not need to have a barrier layer between the sealant layer 15 and the electrostatic ink layer 13. With such a configuration, high-temperature water vapor can more easily penetrate from the sealant layer 15 side than from the base material 11 side having the barrier layer. The

laminates

10 and 10a must maintain sufficiently high cohesive force of the electrostatic ink layer 13 and adhesive force between the electrostatic ink layer 13 and the adhesive layer 14 even when high-temperature water vapor permeates in this way. Can be done. That is, even if the laminate has a structure in which there is no barrier layer between at least one surface and the electrostatic ink layer 13, the cohesive force of the electrostatic ink layer 13 and the relationship between the electrostatic ink layer 13 and the adhesive layer 14 are can maintain a sufficiently high adhesive strength.

The

laminates

10 and 10a can maintain sufficiently high peel adhesion strength no matter which of the

surfaces

10A and 10B is exposed to high-temperature steam. Therefore, even if water vapor is generated from the contents stored in the storage part of the packaging bag and also in a heating chamber such as the inside of a microwave oven, delamination between the layers of the

laminates

10 and 10a can be sufficiently suppressed. be able to.

The structure of the laminate that constitutes the packaging bag is not limited to that shown in FIGS. 1 and 2. For example, between the adhesive layer 14 and the sealant layer 15, there may be two or more combinations of a resin layer (for example, a PET film or a nylon film) and an adhesive layer, or each film may have two or more layers. The structure may be stacked. For example, three or more PET films may be laminated between the adhesive layer 14 and the sealant layer 15. This makes it possible to further increase the heat resistance of the packaging bag.

When the contents contain oil, or when the packaging bag is heated in a microwave oven with high power and/or for a long time, the temperature of the contents contained in the packaging bag may be overheated. Therefore, for example, by creating a laminated structure including four resin layers (resin films) as shown in Examples 1, 2, and 3 below, it is possible to ensure a sufficient distance from the contained object to the electrostatic ink layer. can. By increasing the number of resin layers in this way, the heat resistance of the packaging bag can be made sufficiently high.

Example 1) Transparent vapor-deposited PET film / Primer layer / Electrostatic ink layer / First adhesive layer / PET film / Second adhesive layer / Nylon film / Third adhesive layer / CPP film Example 2) Transparent vapor-deposited PET film / Primer layer / Electrostatic ink layer / First adhesive layer / Nylon film / Second adhesive layer / PET film / Third adhesive layer / CPP film Example 3) Transparent vapor deposited PET film / Primer layer / Electrostatic ink layer / First adhesive layer/PET film/Second adhesive layer/PET film/Third adhesive layer/CPP film

In this way, a laminate containing four or more resin layers (resin films) has excellent heat resistance. If all the resin films other than the sealant layer are PET films as in Example 3, the heat resistance can be further improved. On the other hand, when a nylon film is used as in Examples 1 and 2, the drop strength can be increased. In particular, as in Example 1, if the resin layer bonded to the sealant layer (CPP film) via the third adhesive layer is a nylon film, the drop strength when the packaging bag and packaging body are constructed is further improved. be able to. That is, the packaging bag (packaging body) can be made less likely to be damaged when dropped.

Regardless of the presence or absence of a nylon film, a structure in which four layers of resin (resin films) are laminated has better drop strength than a structure in which three layers (resin films) made of resin are laminated, as in the laminate 10a in FIG. 2. . For example, if the drop strength when the layer structure of the laminate is Example 4 below (resin layers: 3 layers) is taken as the standard (100%), the drop strength of Example 1 above (resin layers: 4 layers) is approximately Improved to 105%.
Example 4) Transparent vapor-deposited PET film/primer layer/electrostatic ink layer/first adhesive layer/nylon film/second adhesive layer/CPP film

The laminate structure of the laminate is not limited to the above example. For example, it may have the laminated structure of Example 5 below. The laminate of Example 5 has excellent tearability. In addition, it has excellent heat resistance compared to the case of example 4 which has a nylon film as an intermediate layer.
Example 5) Transparent vapor deposited PET film/primer layer/electrostatic ink layer/first adhesive layer/PET film/second adhesive layer/CPP film

In each of the above examples 1 to 5, the left end is the base material 11, the right end is the sealant layer 15, and each layer is laminated in order from left to right. The third adhesive layer may be the same adhesive layer as the adhesive layer 14 (first adhesive layer) and the second adhesive layer 17, or may be a different adhesive layer from these.

Still another modification (specific example) of the layered structure of the laminate is illustrated below. In each of these examples, the left end is the base material 11, the right end is the sealant layer 15, and each layer is laminated in order from left to right. Note that the layer structure of the laminate is not limited to the following example.

Example 6) PET film/primer layer/electrostatic ink layer/adhesive layer/LLDPE film (linear low density polyethylene film)
Example 7) Nylon film / Primer layer / Electrostatic ink layer / Adhesive layer / LLDPE film Example 8) Transparent vapor-deposited PET film / Primer layer / Electrostatic ink layer / Adhesive layer / CPP film (unstretched polypropylene film)
Example 9) Barrier nylon film/primer layer/electrostatic ink layer/adhesive layer/CPP film Example 10) Transparent vapor-deposited PET film/primer layer/electrostatic ink layer/first adhesive layer/PET film/second adhesive Layer/Nylon film/Third adhesive layer/CPP film

The packaging bag may be, for example, a two-sided bag, a three-sided bag, a gassho bag, or a studding pouch. For example, a packaging bag may be constructed by folding the above-mentioned laminate 10 (10a) in half so that the sealant layers 15 (surface 10B) face each other and heat sealing the side edges and the top edge. A packaging bag may be constructed by heat-sealing the ends of the two arranged laminates 10 (10a). Alternatively, a packaging bag may be constructed by using three or more laminates 10 (10a) and heat sealing the sealant layers 15 together.

The packaging body 200 shown in FIG. 3 includes a packaging bag 100 and an object 20 accommodated in a housing section 22 of the packaging bag 100. The packaging bag 100 is composed of two

laminates

10a and 10b forming the sides and a laminate 10c (gusset sheet) forming the bottom. The packaging bag 100 has a top seal part 31 at the top end,

side seal parts

33 and 34 at both side ends, and

bottom seal parts

35 and 36 at the bottom end. The upper end seal portion 31 and the side

end seal portions

33 and 34 are formed by overlapping and heat-sealing the sealant layers 15 of the

laminates

10a and 10b.

The lower end seal portion 35 (gusset seal portion) is formed by overlapping and heat-sealing the sealant layers 15 of the

laminates

10a and 10c. The lower end seal portion 36 (gusset seal portion) is formed by overlapping and heat-sealing the sealant layers 15 of the

laminates

10b and 10c. The structure of the

laminates

10a, 10b, 10c may be as shown in FIG. 2. The surface 10B of the

laminates

10a, 10b, and 10c constitutes the accommodating portion 22, and the surface 10A is exposed to the outside.

The sealant layers 15 of the

laminates

10a, 10b, and 10c are heat-sealed at the upper end seal portion 31, side

end seal portions

33, 34, and lower

end seal portions

35, 36. That is, the dotted portions in FIG. 3 indicate the sealed portions formed by heat sealing. The

laminates

10a, 10b, 10c are not heat-sealed in areas other than these sealed areas (non-sealed areas). The unsealed portion of the packaging bag 100 is sealed with each seal portion to form an internal space (accommodating portion 22) that accommodates the contents 20.

The package 200 may be manufactured using the packaging bag 101 shown in FIG. 4. In the packaging bag 101, the upper end 31a of the laminate 10a (10b) is not heat-sealed. Before heat-sealing the upper end 31a, the stored object 20 is inserted through the opening formed by the upper end 31a, and then the upper end 31a of the stacked body 10a (10b) is heat-sealed. By forming the upper end seal portion 31 in this manner, it is possible to obtain the packaging bag 100 and the package 200 in which the contents 20 are sealed in the storage portion 22 of the packaging bag 100, as shown in FIG.

A pair of

notches

41 and 41 are provided in the side

end seal portions

33 and 34 of the packaging bag 100. A planned cutting line (not shown) may be provided to connect the pair of

notches

41, 41. After heating the package 200 in a microwave oven, the end user can open the package 200 from one notch 41 along the cut line and take out the heated contents 20.

The container 20 is not particularly limited, and may contain not only water but also fats and oils. If it contains oil or fat, it may become locally heated, for example, by heating in a microwave oven. The packaging body 200 is composed of the

laminates

10a, 10b, and 10c, which have high sealing strength even at high temperatures, are difficult to peel off even when exposed to high-temperature steam, and have excellent durability, so that delamination and leakage between the layers occur. can be sufficiently suppressed. Examples of the stored items 20 include foods such as curry, stew, soup, boiled food, and grilled food. However, the stored items 20 are not limited to these.

The side end seal portion 34 includes a steam release portion 50 that communicates the storage portion 22 with the outside of the packaging bag 100 when the pressure in the storage portion 22 of the packaging bag 100 increases. The steam release portion 50 projects toward the center C of the packaging bag 100. When the stored item 20 in the storage section 22 is heated by a microwave oven and steam is generated, the storage section 22 expands. The force applied to the upper end seal portion 31, the side

end seal portions

33, 34, and the lower

end seal portions

35, 36 due to expansion increases as the distance from the center C becomes shorter. Therefore, a large force is applied to the steam release portion 50 protruding toward the center C as the stored object 20 is heated. Therefore, when the pressure in the accommodating part 22 becomes equal to or higher than a predetermined value, the side end seal part 34 is peeled off from the inner edge in the steam release part 50, and the accommodating part 22 and the outside of the packaging bag 100 (packaging body 200) are communicated with each other. Then, water vapor escapes from the steam venting section 50. In this way, the steam release section 50 has a function of preventing the packaging bag 100 (packaging body 200) from bursting when the pressure in the storage section 22 increases.

In the steam venting section 50, a non-sealing section 53 is provided outside the side end sealing section 34. As a result, the seal width of the side end seal portion 34 in the steam vent portion 50 is smaller than the seal width of the side end seal portion 34 other than the steam vent portion 50. Therefore, when the pressure inside the housing section 22 increases, a communication hole (steam passage port) that communicates between the housing section 22 and the outside is smoothly formed in the steam venting section 50. In order to sufficiently smoothly vent (exhaust) steam from the housing portion 22 to the outside, the non-sealed portion 53 may be provided with a through hole that penetrates in the stacking direction of the

stacked bodies

10a, 10b.

The minimum seal width of the side end seal portion 34 in the steam vent portion 50 may be 1 to 5 mm, or may be 2 to 4 mm. Thereby, steam can be smoothly vented during heating while maintaining good sealing performance. The shape and position of the steam vent section 50 are not particularly limited. In a modified example, a steam vent part 50 may be provided in the upper end seal part 31 or the side end seal part 33. Regardless of the shape and position, the minimum value of the seal width in the steam vent section 50 may be within the above-mentioned numerical range. A plurality of steam vent sections 50 may be provided.

FIGS. 5(A) and 5(B) show modified examples of the steam venting section. Both FIGS. 5(A) and 5(B) show an enlarged view of the steam venting portion and its vicinity. The steam release part 50A in FIG. 5(A) includes a first seal part 81 extending toward the center C of the packaging bag (FIG. 3), a second seal part 82 extending parallel to the upper end seal part, and a first seal part 82 extending in parallel to the upper end seal part. A third seal portion 83 connects the portion 81 and the second seal portion 82 and extends from the side end seal portion 34 toward the center of the upper end seal portion.

Both the connection portion between the first seal portion 81 and the third seal portion 83 and the connection portion between the third seal portion 83 and the second seal portion 82 are bent. The seal width W ₀ of these connecting portions is smaller than the seal width W ₁ of the side end seal portion 34 in the portion other than the steam vent portion 50A. The seal width W ₀ (minimum seal width in a packaging bag) may be, for example, 1 to 5 mm, or 2 to 4 mm. When the package is heated in a microwave oven to generate water vapor and increase the pressure inside the container, for example, the connecting part between the third seal part 83 and the second seal part 82 (which protrudes convexly toward the center C) The seal part is peeled off from the inner edge at the part), and the accommodating part and the outside communicate with each other. In this way, water vapor is discharged from the steam venting section 50A.

The steam release part 50B in FIG. 5(B) connects the fourth seal part 84 extending along the side edge of the packaging bag (packaging body) and the upper end of the fourth seal part 84 and the upper side end seal part 34a. It has a fifth seal part 85 and a sixth seal part 86 that connects the lower end of the fourth seal part 84 and the lower end seal part 34b. The sixth seal portion 86 extends from the side edge toward the center of the upper end seal portion. The side end seal portion 34 in FIG. 5(B) includes an upper side end seal portion 34a, a fifth seal portion 85, a fourth seal portion 84, a sixth seal portion 86, and a lower side end seal portion 34b.

The connection portion between the fourth seal portion 84 and the sixth seal portion 86 is bent, and the seal width W ₀ of the connection portion is equal to the seal width W 1 of the side end seal portion ₃₄ in the portion other than the steam vent portion 50B. and _W2 . The seal width W ₀ (minimum seal width in a packaging bag) may be, for example, 1 to 5 mm, or 2 to 4 mm. When the package is heated in a microwave oven to generate water vapor and the pressure inside the container increases, the connection part between the fourth seal part 84 and the sixth seal part 86 (the part protruding convexly toward the center C) At this point, the seal portion is peeled off and the storage portion communicates with the outside of the packaging bag (packaging body). In this way, water vapor is discharged from the steam venting section 50B.

The shape of the steam vent part is not limited to the above shape. Any structure may be used as long as it can discharge steam from the housing part to the outside when the pressure in the housing part increases.

The packaging body 210 in FIG. 6 includes a pillow-shaped packaging bag 110 and a container 20 accommodated in the housing section 22 of the packaging bag 110. The packaging bag 110 is made by folding the laminate 10a and heat-sealing the ends of the laminate 10a on the back side to form a sealed portion (not shown), and heat-sealing both side edges to form a side edge seal portion. It can be obtained by forming 33 and 34. The object 20 may be accommodated in the gassho bag before either one of the side

end seal parts

33, 34 is heat-sealed, and then one of the side

end seal parts

33, 34 may be heat-sealed. In this way, the packaging bag 110 and the package 210 can be obtained. Note that a gassho bag in which one of the side

end seal portions

33 and 34 is not sealed before accommodating the contents 20 is also an example of the packaging bag of the present disclosure.

The package 210 has a steam release section 54 formed of a plurality of half-cut lines formed on the laminate 10a. This half-cut line may be formed by laser processing the laminate 10a. The half-cut line may be formed in a portion of the base material 11 from the surface 10A side in FIG. 2, for example. The portion where the half-cut line is formed has lower strength than the portion where the half-cut line is not formed. Therefore, when steam is generated from the stored items due to heating in a microwave oven or the like and the pressure in the storage section 22 increases, the part where the half-cut line is formed is torn and the storage section 22 and the packaging bag 110 (packaging body 210) are separated. Communicates with the outside. As a result, the water vapor within the housing section 22 is discharged to the outside. At this time, each layer constituting the laminate 10a comes into direct contact with high-temperature water vapor, but the occurrence of interlayer delamination in the laminate 10a can be sufficiently suppressed.

The packaging body 202 in FIGS. 7 and 8 includes a packaging bag 102 and an item 20 accommodated in the storage section 22 of the packaging bag 102. The packaging bag 102 can be formed by heat sealing the ends of the three

laminates

10a, 10b, 10d shown in FIG. When the packaging bag 102 is viewed from the front as shown in FIG. 7, the laminate 10d is arranged on the upper side, and the laminate 10a is arranged on the lower side. The lower end of the laminate 10d is folded back so that the surface 10B on the side of the sealant layer 15 faces the front side, and is heat-sealed with the sealant layer 15 at the upper end of the laminate 10a to form a transverse seal portion 38.

The sealant layer 15 of the laminate 10d is heat-sealed with the sealant layer 15 of the laminate 10b (FIG. 8) on the back side at the upper end and side end. The sealant layer 15 of the laminate 10a is heat-sealed at the side and lower ends of the laminate 10b (FIG. 8) on the back side, respectively. In this way, the side

end seal portions

33, 34, the upper end seal portion 31, the lower end seal portion 32, and the transverse seal portion 38 are formed. The transverse seal portion 38 is provided with a non-seal portion 53 . As a result, a steam vent portion 55 is provided which has a smaller seal width than the other seal portions. The minimum seal width in the transverse seal portion 38 provided in the steam vent portion 55 may be 1 to 5 mm, or may be 2 to 4 mm.

When steam is generated from the stored object 20 due to heating and the pressure in the storage section 22 increases, the portion of the transverse seal section 38 in the steam release section 55 where the seal width is the minimum is peeled off, causing the storage section 22 and the packaging bag 102 to separate. (The package 202) communicates with the outside. As a result, the water vapor within the housing portion 22 is discharged to the outside as shown by the arrow in FIG.

The packaging bag 103 (packaging body 203) in FIG. 9 has the same structure as the packaging bag 100 (packaging body 200) in FIG. 3. Like the packaging bag 100, the packaging bag 103 has a shape that allows a self-supporting packaging body 203 to be formed. Specifically, it is composed of two

laminates

10a and 10b forming the side surfaces and a laminate (gusset sheet) forming the bottom surface. The packaging bag 103 has an upper seal part 31 at the upper end,

side seal parts

33 and 34 at both side ends, and

lower seal parts

35 and 36 at the lower end. The upper end seal portion 31 and the side

end seal portions

laminates

10a and 10b.

The laminate 10c (FIG. 10) is sandwiched between the

laminates

10a and 10b, with the sealant layer 15 facing outward. The longitudinal length L3 of the folded laminate 10c may be, for example, 25 to 60 mm. The lower end seal portion 35 (gusset seal portion) is formed by overlapping and heat-sealing the sealant layers 15 of the

laminates

10b and 10c. The structure of the

laminates

10a, 10b, 10c may be as shown in FIG. The hatched portion in FIG. 9 indicates a sealed portion formed by heat sealing. The

laminates

10a, 10b, 10c are not heat-sealed in areas other than these sealed portions. The unsealed portion of the packaging bag 103 is sealed with each seal portion to form an internal space (accommodating portion 22) that accommodates the contents 20.

The package 203 may be manufactured using the packaging bag 104 shown in FIG. In the packaging bag 104, the upper end 31a of the laminate 10a (10b) is not heat-sealed. Before heat-sealing the upper end 31a, the stored object 20 is inserted through the opening formed by the upper end 31a, and then the upper end 31a of the stacked body 10a (10b) is heat-sealed. By forming the upper end seal portion 31 in this manner, it is possible to obtain a packaging body 203 in which the packaging bag 103 and the contents 20 are sealed in the storage portion 22 of the packaging bag 103, as shown in FIG. The contents 20 are the same as those described in the description of the package 200. The seal width (length in the vertical direction) W4 of the upper end seal portion 31 may be, for example, 5 to 25 mm.

The plan view shape (shape seen from the thickness direction) of the packaging bag 104 is a rectangle or a square. The length L1 of the packaging bag 104 along the vertical direction may be, for example, 100 to 180 mm. The length L2 along the lateral direction may be, for example, 100 to 200 mm. The width W3 (horizontal length) of the side

end seal portions

33, 34 may be, for example, 3 to 15 mm.

The packaging bag 104 (packaging bag 103) has a steam release part 50C at the side end. The steam release portion 50C has a top portion 39 on the accommodating portion 22 side. The steam venting section 50C is formed by heat sealing the

laminates

10a and 10b so as to have the shape of the steam venting section 50C. In order to facilitate the escape of steam from the steam venting section 50C, the sealing strength of the steam venting section 50C is smaller than the sealing strength of the sealing sections other than the steam venting section 50C. The sealing strength of the steam vent portion 50C may be, for example, 25 to 50 N/15 mm. The seal width of the steam venting portion 50C may be narrower than the seal widths of the upper end seal portion 31, the side

end seal portions

33, 34, and the lower

end seal portions

35, 36.

A portion surrounded by the side edge 34A and the steam release portion 50C of the packaging bag 104 is an unsealed portion 53 where the laminate 10a and the laminate 10b are not sealed. Since the non-sealed portion 53 is open at the side edge 34A, it functions as a steam vent.

The steam venting section 50C will be further described with reference mainly to FIG. 11. FIG. 11 is an enlarged view of the steam venting section 50C. In FIG. 11, the diagonal lines added to the seal portion in FIG. 9 and the like are omitted from the viewpoint of ease of viewing the drawing. The steam release portion 50C is a triangular (or approximately V-shaped) sealing portion, and has a top portion 39 on the accommodating portion 22 side. The steam venting section 50C is symmetrical with respect to the first virtual line VL1. The first virtual line VL1 is a virtual straight line that passes through the top portion 39 and extends in the horizontal direction. The length L4 between the outer edge of the upper end portion 31a (the upper edge of the packaging bag 104) and the first virtual line VL1 may be, for example, 25 to 70 mm.

The steam venting part 50C has an upper seal part 40 connected to the upper end seal part 34a, and a lower seal part 42 connected to the lower end seal part 34b. The upper seal portion 40 and the lower seal portion 42 are connected at the top portion 39.

The upper seal portion 40 is located closer to the upper end portion 31a than the first virtual line VL1. The upper seal portion 40 has a first edge 401 on the accommodating portion 22 side and a second edge 402 on the non-seal portion 53 side. The seal width of the upper seal portion 40 may be substantially constant, or may become narrower toward the top portion 39, for example.

The lower seal portion 42 is located on the opposite side of the upper seal portion 40 with respect to the first imaginary line VL1. The lower seal portion 42 and the upper seal portion 40 have a line-symmetrical shape with the first imaginary line VL1 as an axis of symmetry when viewed with respect to the first imaginary line VL1. The lower seal portion 42 has a first edge 421 on the accommodating portion 22 side and a second edge 422 on the non-seal portion 53 side. In this embodiment, the seal width of the lower seal portion 42 may be substantially constant, or may become narrower toward the top portion 39, for example.

The upper seal part 40 and the lower seal part 42 are inclined with respect to the first imaginary line VL1 (and the extending direction of the side edge 34A), and in the steam venting part 50C, the upper seal part 40 and the lower seal part 42 are inclined toward the side edge 34A from the top part 39. The distance between the seal portion 40 and the lower seal portion 42 is widened. The angle (angle of inclination) θ1 between the direction in which the upper seal portion 40 (and the lower seal portion 42) extends and the first virtual line VL1 may be, for example, 15 to 45 degrees. The angle between the direction in which the second edge 402 extends and the first virtual line VL1 may also be the same as θ1.

The length L5 between the end 401a of the first edge 401 of the upper seal part 40 and the end 421a of the first edge 421 of the lower seal part 42 may be, for example, 5 to 55 mm. The end 401a is the end of the first edge 401 on the upper side end sealing part 34a side, and is a contact point with the upper side end sealing part 34a. The end 421a is the end of the first edge 421 on the lower side end seal portion 34b side, and is a contact point with the lower side end seal portion 34b.

The length L6 between the end 402a of the second edge 402 of the upper seal part 40 and the end 422a of the second edge 422 of the lower seal part 42 may be, for example, 5 to 55 mm. The end 402a is the end of the second edge 402 closer to the upper end seal portion 34a, and is a contact point with the upper end seal portion 34a. The end 422a is the end of the second edge 422 on the lower side end sealing part 34b side, and is a contact point with the lower side end sealing part 34b.

The top part 39 of the steam venting part 50C may be rounded as shown in FIG. 11 (in other words, it may have a curved surface). In the case where the top portion 39 is rounded, the radius of curvature of the edge of the top portion 39 on the accommodating portion 22 side may be, for example, 3 to 20 mm. The radius of curvature of the edge of the non-sealed portion 53 of the top portion 39 may be, for example, 1.5 to 10 mm. The radius of curvature of the edge of the top portion 39 on the accommodating portion 22 side may be larger than the radius of curvature of the edge on the non-sealing portion 53 side. Thereby, the width (seal width) of the seal portion of the packaging bag 104 (packaging bag 103) can be made smallest at the top 39 of the steam release portion 50C. The seal width W5 (length along the first virtual line VL1) at the top portion 39 may be, for example, 1 to 5 mm, or 1.5 to 4 mm. The length L7 between the tip 39a of the steam venting part 50C on the side of the housing part 22 (the end of the top part 39 closest to the housing part 22) and the inner edge 34B of the side end seal part 34 is, for example, 5 to 20 mm. It's fine.

In the non-sealed part 53 surrounded by the steam release part 50C, a penetration part 44 is formed which penetrates the stacked body 10a and the stacked body 10b in the thickness direction (direction perpendicular to the vertical direction and the horizontal direction). The penetrating portion 44 can be formed, for example, by making an incision (or a cut) in the laminate 10a and the laminate 10b with a blade having the shape of the penetrating portion 44, or by cutting out the laminate 10a and the laminate 10b. can.

The penetrating portion 44 will be explained with reference to FIG. 12. The penetrating portion 44 has a first end 441 and a second end 442. The second end 442 is the end opposite to the first end 441. The penetrating portion 44 may satisfy at least one of the following conditions (1) to (4).

Condition (1): The penetrating portion 44 is non-linear.
The non-linear penetrating portion 44 has a curved portion or a corner portion. In other words, a gap exists between the penetrating portion 44 and the second virtual line VL2. The second virtual line VL2 is a virtual straight line drawn to connect the first end 441 and the second end 442, as shown in FIG.

An example of the non-linear penetrating portion 44 is an arc-shaped penetrating portion. Examples of the arc shape include a circular arc shape, a half-moon shape, a crescent shape, etc. as shown in FIG. The penetrating portion 44 may be U-shaped (or U-shaped) or V-shaped. The radius of curvature of the arc-shaped penetrating portion 44 may be, for example, 2.5 to 10 mm. The length L8 between the first end 441 and the second end 442 may be, for example, 3.5 to 14 mm. The length L8 is the length of the penetrating portion 44 along the second virtual line VL2.

Condition (2): A portion of the penetrating portion 44 exists on the first imaginary line VL1 passing through the top 39 (specifically, the tip 39a) of the steam venting portion 50C. That is, the penetrating portion 44 has at least one intersection with the first virtual line VL1.

Condition (3): A portion of the penetrating portion 44 is located closer to the accommodating portion 22 than the third imaginary line VL3, which is an extension of the edge located closest to the accommodating portion 22 of the upper end seal portion 34a and the lower end seal portion 34b. exists in Specifically, a portion of the penetrating portion 44 is located closer to the accommodating portion 22 of an inner edge 301 of the upper end seal portion 34a on the accommodating portion 22 side and an inner edge 321 of the lower end sealing portion 34b on the accommodating portion 22 side. It exists on the accommodating part 22 side from the third imaginary line VL3, which is an extension of the edge located at . In the example shown in FIG. 12, since the extension line of the inner edge 301 and the extension line of the inner edge 321 match, the third virtual line VL3 is an extension line of the inner edge 301 (or the inner edge 321).

Condition (4): The penetrating portion 44 is arranged within the similar region 37 surrounded by a broken line in FIG. The similar region 37 is a region similar in shape to the non-sealed portion 53, and its ratio to the total area of the non-sealed portion 53 may be 1/4 or more and 2/3 or less. Since the non-sealed portion 53 has a substantially triangular shape, the similar region 37 also has a substantially triangular shape and has an apex 37a. The top portion 37a is located on the first virtual line VL1. In the similar region 37, the bottom side facing the top portion 37a may coincide with the side edge 34A or may be separated from the side edge 34A.

The penetrating portion 44 shown in FIG. 12 may satisfy all of the above conditions (1) to (4). In the penetrating portion 44 shown in FIG. 12, the second virtual line VL2 may pass through the end 422a. The angle θ2 between the second virtual line VL2 and the side edge 34A may be 10 to 45 degrees. In the penetrating portion 44 shown in FIG. 12, the first end 441 is separated from the second edge 402. The length L9a (the length along the second virtual line VL2) between the first end 441 and the second edge 402 may be, for example, 0.5 to 6 mm. The penetrating portion 44 shown in FIG. 12 is an example, and the shape and position of the penetrating portion 44 are not limited to those shown in FIG. 12.

Since each of the above-mentioned packaging bags is composed of the laminates 10a to 10d having the laminate structure shown in FIG. 2, it is possible to sufficiently ensure a high degree of freedom in design through electrostatic printing. Furthermore, when heated in a microwave oven or the like, interlayer peeling is suppressed, and it has excellent durability. When each packaging bag is heated in a microwave oven (output: 600W) for 3 minutes, the width of the delamination at the seal portion may be 0.5 mm or less, 0.3 mm or less, and 0.1 mm or less. It's okay. With such a packaging bag, the contents can be sufficiently heated in a microwave oven or the like. The above-mentioned "sealed part" is a part where the sealant layers of the laminate forming the packaging bag are thermally fused together by heat sealing, and includes the above-mentioned upper end seal part 31, side

end seal parts

33 and 34, and lower end seal part. It is a general term for 32, 35, and 36. In any of these seal portions, the width of the delamination may be within the above-mentioned range.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments in any way. For example, the above-mentioned packaging bag may be composed of the laminate 10 of FIG. 1 or a modification thereof instead of the laminates 10a to 10d.

The present disclosure includes the following embodiments.

[1] A packaging bag composed of one or more laminates and having a storage section,
The laminate includes a sealant layer, an adhesive layer, an electrostatic ink layer, a primer layer, and a base material in this order from the accommodating part side,
The adhesive layer includes an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, a cured product thereof, or a mixture thereof,
A packaging bag, wherein the ratio of the thickness of the adhesive layer to the thickness of the electrostatic ink layer is 0.15 to 5.
[2] The packaging bag according to [1], wherein the electrostatic ink layer has a thickness of 6 μm or less.
[3] The packaging bag according to [1] or [2], wherein the total thickness of the adhesive layer and the electrostatic ink layer is 2 to 20 μm.
[4] The packaging bag according to any one of [1] to [3], wherein the polyol includes an aliphatic polyester polyol, and the epoxy compound includes one having an epoxy group at both ends.
[5] A sealing portion formed by heat-sealing opposing sealant layers to each other,
The packaging bag according to any one of [1] to [4], wherein the seal portion includes a steam release portion that communicates the storage portion with the outside when the pressure of the storage portion increases.
[6] The packaging bag according to [5], wherein the minimum seal width of the seal portion in the steam release portion is 1 to 5 mm.
[7] The laminate has a half-cut line in the non-sealed portion for communicating the accommodation part with the outside and forming a steam passage hole when the pressure in the accommodation part increases.[1] The packaging bag described in any one of ~[6].
[8] The packaging bag according to any one of [5] to [7], wherein the width of the delamination of the seal portion is 0.5 mm or less when heated in a microwave oven (output: 600 W) for 3 minutes. .
[9] The peel adhesion strength of the outer surface of the laminate after being exposed to an atmosphere containing water vapor is S1, and the peel adhesion strength of the inner surface of the laminate after being exposed to the atmosphere is S2. The packaging bag according to any one of [1] to [8], wherein S2/S1 is 0.6 to 1.6.
[10] The packaging bag according to any one of [1] to [9], wherein the epoxy compound includes a bifunctional alicyclic epoxy compound.
[11] The packaging bag according to any one of [1] to [10], wherein the polyisocyanate includes a xylylene diisocyanate derivative.
[12] The packaging bag according to any one of [1] to [11], wherein the base material has a resin layer serving as an outermost layer and a barrier layer closer to the adhesive layer than the resin layer.
[13] The packaging bag according to [12], wherein the barrier layer includes at least one selected from the group consisting of an alumina vapor-deposited layer and a silica vapor-deposited layer.
[14] The packaging bag according to any one of [1] to [13], which is for heating in a microwave oven.
[15] A package comprising the packaging bag according to any one of [1] to [14] above, and a container to be stored in the storage section of the packaging bag.
[16] The package according to [15], wherein the content contains oil and fat.

The packaging bags of [1] to [13] above have an adhesive layer that can maintain the cohesive force of the electrostatic ink layer and maintain sufficiently high adhesive strength even when heated and in contact with high-temperature steam. Be prepared. Therefore, an electrostatic ink layer that inherently has low heat resistance can be used in packaging bags that are heated or cooked. Because the thickness ratio between the adhesive layer and the electrostatic ink layer is within a predetermined range, even though the electrostatic ink layer is present, the pressure inside the container increases and it does not come into contact with high-temperature water vapor. , interlayer peeling can be sufficiently suppressed. For this reason, it has excellent durability even when heated while sufficiently ensuring a high degree of design freedom through electrostatic printing.

Since the above-mentioned package [14] or [15] is equipped with the above-mentioned packaging bag, it has excellent durability even when heated while sufficiently ensuring a high degree of design freedom through electrostatic printing. has.

[21] A packaging bag for heating in a microwave oven, which is composed of one or more laminates and has a storage part,
The laminate includes a sealant layer, an adhesive layer, an electrostatic ink layer, a primer layer, and a base material in this order from the accommodating part side,
The adhesive layer includes an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, a cured product thereof, or a mixture thereof,
A packaging bag, wherein the ratio of the thickness of the adhesive layer to the thickness of the electrostatic ink layer is 0.15 to 5.
[22] The packaging bag according to [21], wherein the electrostatic ink layer has a thickness of 6 μm or less.
[23] The packaging bag according to [21] or [22], wherein the total thickness of the adhesive layer and the electrostatic ink layer is 2 to 20 μm.
[24] A sealing portion formed by heat-sealing opposing sealant layers to each other, and the sealing portion includes a steam venting portion that communicates the accommodation portion with the outside when the pressure in the accommodation portion increases. , the packaging bag according to any one of [21] to [23].
[25] The packaging bag according to any one of [21] to [24], wherein a minimum seal width of the seal portion in the steam release portion is 1 to 5 mm.
[26] The laminate has a half-cut line in the non-sealed portion for communicating the accommodation part with the outside and forming a steam passage hole when the pressure in the accommodation part increases.[21] The packaging bag described in any one of ~[25].
[27] The packaging bag according to any one of [21] to [26], wherein the width of the delamination of the seal portion is 0.5 mm or less when heated in a microwave oven (output: 600 W) for 3 minutes. .
[28] The peel adhesion strength of the outer surface of the laminate after being exposed to an atmosphere containing water vapor is S1, and the peel adhesion strength of the inner surface of the laminate after being exposed to the atmosphere is S2. The packaging bag according to any one of [21] to [27], wherein S2/S1 is 0.6 to 1.6.
[29] The packaging bag according to any one of [21] to [28], wherein the polyol includes an aliphatic polyester polyol, and the epoxy compound includes one having an epoxy group at both ends.
[30] The packaging bag according to any one of [21] to [29], wherein the epoxy compound includes a bifunctional alicyclic epoxy compound.
[31] The packaging bag according to any one of [21] to [30], wherein the polyisocyanate includes a xylylene diisocyanate derivative.
[32] The packaging bag according to any one of [21] to [31], wherein the base material has a resin layer serving as an outermost layer and a barrier layer closer to the adhesive layer than the resin layer.
[33] The packaging bag according to [32], wherein the barrier layer includes at least one selected from the group consisting of an alumina vapor-deposited layer and a silica vapor-deposited layer.
[34] A package for heating in a microwave oven, comprising the packaging bag according to any one of [21] to [33] above, and an object to be accommodated in a storage section of the packaging bag.
[35] The package according to [34], wherein the content contains oil and fat.

The packaging bags of [21] to [33] above have an adhesive that maintains the cohesive force of the electrostatic ink layer even when heated in a microwave oven and comes into contact with high-temperature steam, and maintains sufficiently high adhesive strength. It is equipped with an agent layer. Therefore, an electrostatic ink layer that inherently has low heat resistance can be used in packaging bags that are heated or cooked in a microwave oven. Because the thickness ratio between the adhesive layer and the electrostatic ink layer is within a predetermined range, even though the electrostatic ink layer is present, the pressure inside the container increases and it does not come into contact with high-temperature water vapor. , interlayer peeling can be sufficiently suppressed. Therefore, it has excellent durability when heated in a microwave oven while sufficiently ensuring a high degree of design freedom through electrostatic printing.

Since the above-mentioned package [34] or [35] is equipped with the above-mentioned packaging bag, it has a high degree of design freedom due to electrostatic printing, and has excellent properties when heated in a microwave oven. Durable.

The contents of the present disclosure will be described in more detail with reference to Examples and Comparative Examples, but the present disclosure is not limited to the Examples below.

(Example 1)
[Preparation of laminate]
As a base material, an alumina-deposited PET film (manufactured by Toppan Printing Co., Ltd., trade name: GLARHF, thickness: 12 μm) was prepared. A water-based primer resin (resin containing polyethyleneimine, manufactured by Michelman, trade name: DP050) was applied to the alumina-deposited surface of this alumina-deposited PET film to form a primer layer. The aqueous polyethyleneimine was applied in an amount of 0.10 to 0.18 g/m ² .

An electrostatic ink composition was applied to the surface of the primer layer using a digital printing machine (manufactured by HP, Indigo 20000 digital printing machine for labels and packages) to form an electrostatic ink layer having a predetermined thickness. As the electrostatic ink composition, an electrostatic ink composition (HP Indigo Electroink) containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid was used.

The main ingredient is an aliphatic polyester polyol (manufactured by Mitsui Chemicals, Inc., product name: Takelac A626, hereinafter sometimes referred to as "(A)"), and the curing agent is polyisocyanate (manufactured by Mitsui Chemicals, Inc., product name: Takenate A50). , hereinafter sometimes referred to as "(B)"), 3',4'-epoxycyclohexylmethyl-3,4 epoxycyclohexane carboxylate (hereinafter sometimes referred to as "C") as an epoxy compound, and , ethyl acetate was blended as a solvent to prepare an adhesive composition having a solid content concentration of 36.5% by mass. The mass-based compounding ratio (mass basis) of each component was (A):(B):(C)=8:1.5:1.5.

The adhesive composition prepared as described above was applied to the electrostatic ink layer using a dry laminating device to form an adhesive layer having a predetermined thickness.

A laminated film was prepared by bonding a nylon film (thickness: 15 μm) and an unstretched polypropylene film (thickness: 60 μm) together using a commercially available urethane adhesive. Using the dry laminating apparatus described above, the nylon film and the adhesive layer were bonded together so that the adhesive layer on the base material and the nylon film of the laminated film faced each other. Thereafter, aging was performed at 40° C. for two days to obtain a laminate 10e having a laminate structure as shown in FIG.

(Examples 2 to 5)
The thicknesses of the electrostatic ink layer and the adhesive layer were changed by changing the amount of the electrostatic ink composition applied to the surface of the primer layer and the amount of the adhesive composition applied to the electrostatic ink layer. A laminate was produced in the same manner as in Example 1 except for this.

(Comparative Examples 1 to 5)
Laminates were produced in the same manner as Examples 1 to 5, except that the epoxy compound (C) was not blended when preparing the adhesive composition.

[Evaluation of laminate]
<Measurement of thickness of each layer>
The thickness of the electrostatic ink layer was measured by observing the cut surface obtained by cutting the laminate produced in each example and each comparative example along the thickness direction with a scanning electron microscope (SEM, magnification: 1500 times). and the thickness of the adhesive layer was measured. The thicknesses of the electrostatic ink layer and the adhesive layer in the laminates of each Example and each Comparative Example were approximately uniform. The thickness of the electrostatic ink layer (TI), the thickness of the adhesive layer (TA), and their total value (TI+TA) in the laminates of each Example and each Comparative Example were as shown in Table 1. Further, the ratio of TA to TI was as shown in Table 1.

<Evaluation of laminate (1)>
50 mL of water was placed in a plastic container. As shown in FIG. 13(A), the opening of the plastic container 70 was covered with the laminate 10e produced in each Example and each Comparative Example to close the opening. At this time, the laminate was placed over the plastic container so that the PET film layer (surface 10A) of the alumina-deposited PET film faced the water surface 70a in the plastic container. With the opening closed with the laminate in this manner, the plastic container was placed in a microwave oven and heated at 600 W for 3 minutes. Thereafter, the laminate was taken out of the microwave oven, and the peel adhesion strength was measured according to the following procedure.

The peel adhesion strength of the laminate 10e taken out from the microwave oven was measured in accordance with JIS K 6854-1:1999. Specifically, the laminate was cut to a width of 15 mm to prepare a measurement sample. After peeling off the nylon film and alumina-deposited PET film at the edge of the measurement sample, use a tensile tester at an angle of 90°, a tensile speed of 300 mm/min, and room temperature (20 ° C.). The peel adhesion strength between the nylon film and the alumina-deposited PET film was measured. This peel-off adhesive strength was defined as peel-off adhesive strength [S1]. The peel adhesion strength [Sb] of the laminate 10e before being placed over the plastic container was also measured using the same procedure. The measurement results were as shown in Table 2. Table 2 also shows the value of S1/Sb.

<Evaluation of laminate (2)>
The orientation of the laminate 10e to be placed over the plastic container was opposite to <Evaluation of laminate (1)>. That is, as shown in FIG. 13(B), the laminate 10e was placed over the opening of the plastic container 70 so that the unstretched polypropylene film (surface 10B) and the water surface 70a in the plastic container 70 faced each other. Except for this, the peel adhesive strength [S2] after steam heating was measured in the same manner as <Evaluation of laminate (1)>. The measurement results were as shown in Table 2. Table 2 also shows the values of S1/Sb and S2/S1.

<Evaluation of laminate (3)>
The heat resistance creep of the laminates of each Example and each Comparative Example was measured according to the following procedure. First, each laminate 10e was cut into a 15 mm strip. Next, the ends of the strip-shaped sample were separated between the nylon film and the alumina-deposited PET film. Heat-resistant creep was measured in a high-temperature environment of 120° C. while holding the alumina-deposited PET film at the peeled portion and applying a load to generate a shearing force between the nylon film and the unstretched polypropylene film. The results were as shown in Table 2.

As shown in Table 2, in the laminates 10e of Examples 1 to 5, not only the peel adhesion strength Sb before heat treatment in a microwave oven but also the peel adhesion strengths S1 and S2 after heat treatment were sufficiently high. In the laminates of Examples 1 to 5, both S1/Sb and S2/Sb were close to 1, and it was confirmed that the peel adhesion strength did not decrease much even when exposed to high-temperature water vapor. On the other hand, in the laminates of Comparative Examples 1 to 5, the peel adhesion strength S1 was significantly lower than that of Sb, and the value of S1/Sb was significantly smaller than that of Examples 1 to 5. This is thought to be due to a decrease in the cohesive force of the electrostatic ink layer and/or the adhesive force between the electrostatic ink layer and the adhesive layer due to heating by water vapor from the alumina-deposited PET film side, which is the base material. . On the other hand, the reason why the S2/Sb values did not differ significantly between the examples and comparative examples is that the amount of heat accompanying heating by water vapor was absorbed by the unstretched polypropylene film and the nylon film, and sufficiently reached the electrostatic ink layer. This is probably because there was no such thing.

In all Examples and Comparative Examples, the peel adhesion strength was S1≦S2. However, the value of S2/S1 was larger in the example than in the comparative example. Further, regardless of the thickness of the electrostatic ink layer and the adhesive layer, in Examples 1 to 5, the value of S2/S1 could be maintained sufficiently high. From this, it was confirmed that the laminate of the example could maintain high peel adhesion strength even when both surfaces (

surfaces

10A and 10B) were in contact with heated water vapor. Such a laminate can be suitably used for packaging bags in which both surfaces are in contact with water vapor. It was also confirmed that the heat resistance creep was considerably higher in the examples than in the comparative examples. From this, the laminates of Examples 1 to 5 have sufficiently high heat resistance even when used in environments exceeding 100°C.

[Production of packaging bag (packaging body)]
The pair of laminates of Example 1 were heat-sealed under conditions of 180° C., 0.2 MPa, and 1 second so that the unstretched polypropylene films overlapped each other. As a result, the non-stretched polypropylene films were thermally welded together to produce a three-sided bag. After putting 100 mL of water into this three-sided bag, the opening of the three-sided bag was heat-sealed under the same conditions as above to obtain a packaging bag (packaged body) in which water (content) was sealed. This was used as the packaging bag (packaging body) of Example 1. Using each of the laminates of Examples 2 to 5 and Comparative Examples 1 to 5, packaging bags (packages) were produced in the same manner as in Example 1. These were used as packaging bags (packages) of Examples 2 to 5 and Comparative Examples 1 to 5, respectively.

[Evaluation of packaging bag (packaging body)]
The packages produced in each example and each comparative example were placed in a microwave oven and heated at 600 W for 3 minutes. As a result, some of the water in the packaging bag evaporated, causing the packaging bag to expand. Thereafter, the package was taken out of the microwave oven, and the presence or absence of delamination and the peel adhesion strength of the laminate were measured according to the following procedure.

The presence or absence of delamination in the seal portion was visually confirmed. FIG. 14 is a photograph showing an example of delamination. Delamination occurred at the inner edge of the seal portion 130. When delamination occurred, the maximum value of the width W of the delamination was measured using a magnifying microscope as shown in FIG. 14. The presence or absence of delamination and the maximum value of the delamination width W are as shown in Table 3.

A sample was prepared by cutting out the unsealed portion of the laminate from the packaging bag taken out of the microwave oven. The peel adhesion strength [S3] of this sample was measured using the same procedure as <Evaluation of laminate (1)>. The measurement results were as shown in Table 3. Further, the laminate in the non-sealed part was cut out from the packaging bag before heating in the microwave oven, and the peel adhesion strength (before heating, [S0]) was measured using the same procedure. The measurement results were as shown in Table 3. Table 3 shows the ratio (intensity ratio) of S3 to S0.

Delamination did not occur in the packaging bags (packages) of Examples 1 to 4. It was confirmed that delamination tends to occur as the thickness of the electrostatic ink layer increases. From the results of the strength ratio of peel adhesion strength of Examples 1 to 5, it was found that the laminates of Examples 1 to 5 had high peel adhesion even when exposed to high temperature steam, regardless of the thickness of the electrostatic ink layer and the adhesive layer. It was confirmed that the strength was maintained and delamination could be suppressed.

[Evaluation of seal strength]
The pair of laminates of Example 3 were heat-sealed under conditions of 180° C., 0.2 MPa, and 1 second so that the unstretched polypropylene films overlapped each other. In this way, a measurement sample with a width of 15 mm was prepared in which the non-stretched polypropylene films were heat-sealed together. The seal strength of the prepared measurement sample was measured in accordance with JIS K 7127:1999. The peel strength between the heat seals was measured using a tensile tester under the conditions of a peel angle: 90°, a tensile speed: 300 mm/min, and room temperature (20° C.). This peel strength was defined as the seal strength before heat treatment [S4]. The measurement results were as shown in Table 4.

The seal strength of another measurement sample prepared using the same procedure was measured in a 100°C environment. The measurement method was the same as that for seal strength [S4] except for the temperature. This seal strength was defined as seal strength [S5]. The measurement results were as shown in Table 4.

A laminate was produced using the same procedure as Comparative Example 3, except that a gravure printing machine was used instead of a digital printing machine, and a normal ink composition for gravure printing was used instead of an electrostatic ink composition. . This laminate was designated as Comparative Example 6. A pair of laminates of Comparative Example 6 were heat-sealed so that the non-stretched polypropylene films overlapped each other. The heat sealing conditions were the same as in Example 3. In this way, a measurement sample with a width of 15 mm was prepared in which the non-stretched polypropylene films were heat-sealed together. Using this measurement sample, seal strength [S4] and seal strength [S5] were measured in the same manner as the measurement sample of Example 3. The measurement results were as shown in Table 4.

From the results shown in Table 4, it was confirmed that high-temperature seal strength equivalent to gravure printing can be achieved even in the case of digital printing.

DESCRIPTION OF

SYMBOLS

10, 10a, 10b, 10c, 10d, 10e... Laminate, 10A, 10B... Surface, 11... Base material, 12... Primer layer, 13... Electrostatic ink layer, 14... Adhesive layer, 15... Sealant layer, 16 ...Resin layer, 17...Second adhesive layer, 20...Accommodated object, 22...Accommodating part, 31...Upper end seal part, 31a...Upper end part, 32, 35, 36...Lower end seal part, 33, 34...Side end seal Part, 34a... Upper side end seal part, 34b... Lower side end seal part, 34A... Side edge, 35, 36... Lower end seal part, 37... Similar area, 38... Transverse seal part, 39... Top part, 40... Upper seal Part, 41... Notch, 42... Lower seal part, 44... Penetration part, 50, 50A, 50B, 50C, 54, 55... Steam release part, 53... Unsealed part, 70... Plastic container, 70a... Water surface, 81... First seal part, 82... Second seal part, 83... Third seal part, 84... Fourth seal part, 85... Fifth seal part, 86... Sixth seal part, 100, 101, 102, 103, 104, 110... Packaging bag, 130... Seal portion, 200, 202, 203, 210... Packaging body.

Claims

A packaging bag composed of one or more laminates and having a storage part,
The laminate includes a sealant layer, an adhesive layer, an electrostatic ink layer, a primer layer, and a base material in this order from the accommodating part side,
The adhesive layer includes an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, a cured product thereof, or a mixture thereof,
A packaging bag, wherein the ratio of the thickness of the adhesive layer to the thickness of the electrostatic ink layer is 0.15 to 5.
The packaging bag according to claim 1, wherein the electrostatic ink layer has a thickness of 6 μm or less.
The packaging bag according to claim 2, wherein the total thickness of the adhesive layer and the electrostatic ink layer is 2 to 20 μm.
The packaging bag according to claim 3, wherein the polyol includes an aliphatic polyester polyol, and the epoxy compound includes one having epoxy groups at both ends.
Equipped with a seal portion formed by heat sealing opposing sealant layers,
The packaging bag according to claim 4, wherein the seal section includes a steam release section that communicates the accommodation section with the outside when the pressure in the accommodation section increases.
The packaging bag according to claim 5, wherein the minimum seal width of the seal portion in the steam release portion is 1 to 5 mm.
7. The laminate according to claim 1, wherein the laminate has a half-cut line in a non-sealed portion for communicating the accommodating part with the outside and forming a steam passage hole when the pressure in the accommodating part increases. The packaging bag described in any one of the items.
The packaging bag according to claim 5 or 6, wherein the width of delamination of the seal portion is 0.5 mm or less when heated in a microwave oven (output: 600 W) for 3 minutes.
When the peel adhesion strength after the outer surface of the laminate is exposed to an atmosphere containing water vapor is S1, and the peel adhesion strength after the inner surface of the laminate is exposed to the atmosphere is S2, The packaging bag according to any one of claims 1 to 6, wherein S2/S1 is 0.6 to 1.6.
The packaging bag according to any one of claims 1 to 6, wherein the epoxy compound includes a bifunctional alicyclic epoxy compound.
The packaging bag according to any one of claims 1 to 6, wherein the polyisocyanate includes a xylylene diisocyanate derivative.
The packaging bag according to any one of claims 1 to 6, wherein the base material has a resin layer serving as an outermost layer and a barrier layer closer to the adhesive layer than the resin layer.
The packaging bag according to claim 12, wherein the barrier layer includes at least one selected from the group consisting of an alumina vapor-deposited layer and a silica vapor-deposited layer.
The packaging bag according to any one of claims 1 to 6, which is for heating in a microwave oven.
A packaging body comprising the packaging bag according to any one of claims 1 to 6, and a container to be stored in the storage section of the packaging bag.
The package according to claim 15, wherein the content contains oil and fat.