WO2022153705A1

WO2022153705A1 - Container and heating packaging bag

Info

Publication number: WO2022153705A1
Application number: PCT/JP2021/044265
Authority: WO
Inventors: 雅文堀内; 恵介山口
Original assignee: 凸版印刷株式会社
Priority date: 2021-01-13
Filing date: 2021-12-02
Publication date: 2022-07-21
Also published as: JP7369342B2; TW202237494A; JPWO2022153705A1; KR20230132803A; JP2023121833A

Abstract

This container is provided with a body part having a curved section, wherein the body part is configured from at least one laminate, the laminate includes a substrate, a primer layer, an adhesive layer and a sealant layer, in that order, and has a printed surface configured from an electrostatic ink composition in at least part of the sealant layer-side primary surface of the primer layer; the adhesive layer contains an epoxy compound-containing adhesive composition and/or the cured product thereof.

Description

Container and packaging bag for heating

This disclosure relates to containers and packaging bags for heating. The container according to the present disclosure particularly relates to a container composed of at least one laminated body and having a bent portion.

A container (for example, a packaging bag) for sealing and storing an object to be packaged such as food is known. As the container, a package using a thin film or sheet is often used. Various information such as decorations, products, brands, manufacturers, etc. are printed on such containers. As a means for performing such printing, digital printing using an electrostatic ink composition is known. A digital printing machine is used for digital printing.

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 label and digital for packaging) is applied to the coated surface. It has been proposed to perform electrostatic printing using a printing machine) and to apply a cross-linking composition. After performing the predetermined steps in this way, the first flexible base material coated with the predetermined component and the second flexible base material are laminated to form a laminate (packaging material for a container). ) Has been proposed.

JP-A-2018-530478

Since digital printing using an electrostatic ink composition can be handled in small lots, digitally printed laminates are used as materials for various containers. However, the electrostatic ink layer composed of the printing portion provided by the digital printing machine may not have sufficient adhesive strength with the primer layer or the adhesive layer, and when an external force is applied, the electrostatic ink layer and the primer are applied. Peeling can occur between the layers or between the electrostatic ink layer and the adhesive layer. In particular, when the laminated body is bent and its deformation is large, the stress generated between the laminated bodies is large, and peeling or the like may occur between the electrostatic ink layer and the primer layer or the adhesive layer. In such a situation, for example, the function as a container may be impaired, the printed surface may be displaced, and the print information written on the printed surface may be difficult to read. It is possible to consider measures that do not provide a printing surface on the bent portion, but in order to meet various demands, it is required to print on the bent portion as well. Therefore, it is useful if there is a container in which the function as a container is not impaired and the print information is not impaired even when the container has a bent portion.

In addition, the electrostatic ink layer provided by the digital printing machine may not have sufficient adhesive strength with the adjacent layer. Therefore, when the packaging material prepared by the above means is used for a packaging bag that is premised on heat treatment such as boiling and retort, the packaging bag may be broken during heating.

One of the purposes of the present disclosure is to have an interface between an electrostatic ink layer and a primer layer and an electrostatic ink layer even in a bent portion generated in a manufacturing process while having a printed surface printed by a digital printing machine. It is to provide a container in which peeling is suppressed at the interface between the ink and the adhesive layer.

Further, one of the objects of the present disclosure is to provide a packaging bag for heating which has an electrostatic ink layer by a digital printing machine and has sufficient resistance to heat treatment.

One form of the present disclosure is a container including a body portion having a bent portion, wherein the body portion is composed of at least one laminated body, and the laminated body includes a base material, a primer layer, an adhesive layer, and the like. And a sealant layer in this order, and at least a part of the main surface of the primer layer on the sealant layer side has a printed portion composed of an electrostatic ink composition, and the adhesive layer is an adhesive containing an epoxy compound. Provided is a container containing at least one of an agent composition and a cured product thereof.

In the above container, since the adhesive layer is composed of at least one of a specific adhesive composition and a cured product thereof, a sufficient adhesive state can be maintained even at the bent portion, and the electrostatic ink layer and the primer can be maintained. Peeling at the interface with the layer and the interface between the electrostatic ink layer and the adhesive layer is suppressed. In addition, since the adhesive state between the layers is maintained even in the bent portion, the occurrence of misalignment of the printed portion is suppressed, and the print information in the body portion including the bent portion is maintained in the initial state in which printing is performed. Can be done. In the process of using the container, for example, even if a new bent portion is generated due to bending of the container or the like, the adhesive state between the layers is maintained, so that the function as a container (for example, barrier property) can be achieved. Can be maintained for the duration of use. Similarly, the breakage of the container itself and the deterioration of printed information can be suppressed over the period of use.

The bent portion may have the printed portion. Since the body portion of the container according to the present disclosure is made of the above-mentioned specific laminated body, changes in print information are suppressed even when the printing portion is located at the bent portion.

The epoxy compound may include a bifunctional alicyclic epoxy compound. Since the epoxy compound is bifunctional, the number of cross-linking points with the electrostatic ink composition can be increased, and the main surface (printing surface) of the primer layer and the adhesive layer can be adhered more firmly.

The adhesive composition may further contain a polyol, the polyol may contain an aliphatic polyester polyol, and the epoxy compound may include those having epoxy groups at both ends. Such an adhesive layer can exhibit high laminating strength particularly even in a high temperature environment.

The adhesive composition may further contain a polyisocyanate, and the polyisocyanate may contain a xylylene diisocyanate derivative. Such polyisocyanates and polyols are excellent in reactivity. As a result, the curability of the adhesive composition is improved, and the peeling at the interface between the printing part (electrostatic ink layer) and the primer layer and the interface between the printing part (electrostatic ink layer) and the adhesive layer is further improved. Can be suppressed.

A spout that connects to the body may be further provided.

The spout may have a tubular spout and a flange extending outward from the peripheral edge of the lower end of the spout.

The body portion may be composed of one of the above laminated bodies.

The body may be composed of two laminated bodies having a side sheet and one laminated body having a bottom sheet.

Further, in order to achieve the above object, the heating packaging bag according to one embodiment of the present disclosure is composed of a laminate having a base material, a primer layer, an electrostatic ink layer, an adhesive layer, and a sealant layer in this order. A packaging bag for heat treatment, the adhesive layer contains at least one of an adhesive composition containing an epoxy compound and a cured product thereof.

The printed portion formed by printing the electrostatic ink composition with a digital printing machine tends to be inferior in heat resistance and strength as compared with the case where other inks are used. Therefore, when an attempt is made to apply a laminate having a printing portion (electrostatic ink layer) derived from a conventional electrostatic ink composition to a packaging bag for heat treatment, the adhesiveness in the vicinity of the printed surface is inferior, so that the packaging bag May be damaged. On the other hand, according to the above configuration, the curing of the adhesive composition containing the epoxy compound suppresses the deformation of the laminated body due to heating or the like, so that the heating has sufficient resistance to heat treatment. A packaging bag for use is obtained.

The primer layer may contain a polyethyleneimine resin. Since it has a primer layer containing a polyethyleneimine resin, water resistance is also improved, and sufficient resistance to heat treatment in an environment where a large amount of water is present, such as boil heat treatment or retort heat treatment, can be obtained.

The outer peripheral portion may include a sealing portion for adhering the sealant layers of the two laminated bodies to each other, and the sealing portion may have an aspect in which the ink coverage of the electrostatic ink layer is 300% or less. Since the seal portion is a region where heat-bonding processing such as heat sealing is performed, the possibility of breakage is higher than in other regions. On the other hand, by setting the ink coverage of the electrostatic ink layer within the above range, it is possible to secure more sufficient resistance to heat treatment for the sealed portion, and to provide stronger resistance to heat treatment. A packaging bag for heating can be obtained.

The epoxy compound may include a bifunctional alicyclic epoxy compound. By being bifunctional, such an epoxy compound can increase the number of cross-linking points with the electrostatic ink composition and bond the adhesive layer and the printed surface of the primer layer more firmly.

The adhesive composition may further contain a polyol, the polyol may contain an aliphatic polyester polyol, and the epoxy compound may include those having epoxy groups at both ends. Such an adhesive layer has high adhesive strength even in a high temperature environment. Therefore, even when the heating packaging bag is heat-treated, it is possible to sufficiently suppress the breakage of the electrostatic ink composition and the damage of the packaging bag.

The adhesive composition may further contain a polyisocyanate, and the polyisocyanate may contain a xylylene diisocyanate derivative. Such polyisocyanates and polyols are excellent in reactivity. As a result, the curability of the adhesive composition is improved, so that deformation of the packaging bag for heating and the like can be suppressed.

According to the present disclosure, while having a printed surface printed by a digital printing machine, the interface between the electrostatic ink layer and the primer layer and the electrostatic ink layer and the adhesive are also formed at the bent portion generated in the manufacturing process. It is possible to provide a container in which peeling at the interface with the layer is suppressed.

According to the present disclosure, there is provided a packaging bag for heating that has an electrostatic ink layer produced by a digital printing machine and has sufficient resistance to heat treatment.

FIG. 1 is a perspective view showing an example of a container. FIG. 2 is a schematic cross-sectional view showing an example of a container provided with a spout. FIG. 3 is a perspective view showing another example of the container. FIG. 4 is an end view taken along line IV-IV of FIG. FIG. 5 is a cross-sectional view showing an example of the laminated body. FIG. 6 is a cross-sectional view showing another example of the laminated body. FIG. 7 is a plan view showing an example of a packaging bag. FIG. 8 is a plan view showing another example of the packaging bag. FIG. 9 is a reference diagram showing the results of the peeling suppression performance evaluation in the examples. FIG. 10 is a reference diagram showing the results of the peeling suppression performance evaluation in the examples. FIG. 11 is a reference diagram showing the results of the peeling suppression performance evaluation in the examples. FIG. 12 is a diagram for explaining the shape of the seal portion of the package according to the examples and the comparative examples.

The embodiments of the present disclosure will be described below 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 are used for the same elements or elements having the same function, and duplicate description may be omitted in some cases. In addition, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown.

Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component in the composition are present, unless otherwise specified. ..

[container]
One embodiment of the container is a container including a body portion having a bent portion, the body portion is composed of at least one laminated body, and the laminated body includes a base material, a primer layer, an adhesive layer, and an adhesive layer. The sealant layer is contained in this order, and a printing portion composed of an electrostatic ink composition is provided on at least a part of the main surface of the primer layer on the sealant layer side. The container may be, for example, a packaging bag, a tube container, a standing pouch, or the like. The packaging bag is not limited to the one used at room temperature, and may be a packaging bag that is exposed to temperature changes such as for heating and for freezing. The container may be, for example, a container that is expected to further form a crease during use. In a tube container or the like, a new crease may be formed in the body portion when the packaged object is taken out of the container by pressing and deforming the body portion. In the case of the container of the present disclosure, since the adhesive state between the layers is maintained even in such a case, the function as a container (for example, barrier property) can be maintained over the period of use.

FIG. 1 shows an example of a container. The container 100 is composed of one sheet of the laminated body 300. In the container 100, first, the sealant layers on the two opposite sides of the substantially rectangular laminated body 300 are bonded to each other with a predetermined width to form a seal portion 101 to form a tubular body, and then the tubular body further holds the container 100. It is a container obtained by sticking sealant layers to each other with a predetermined width at one of the openings to form a seal portion 103. The container 100 has a bent portion 60 and sealing

portions

101 and 103 in the body portion 200. The bent portion 60 is formed by bending the seal portion 101 along the side surface of the body portion 200 in order to improve the handleability when used as a container.

The container 100 shown in FIG. 1 includes a container portion 102 formed by a sealed

portion

101 and 103 and a non-sealed portion (sheet portion) for accommodating an object to be packaged (for example, food and drink). In the present specification, a package containing and sealed an object to be packaged is also referred to as a package. The sealing portion 103 at the lower end may be sealed after the container 102 is filled with the object to be packaged. The

seal portions

101 and 103 are configured by heat-sealing the sealant layers of the laminated body 300 with each other.

The container 100 may further include a spout that connects to the body portion 200. FIG. 2 is a schematic cross-sectional view showing an example of a container provided with a spout. In FIG. 2, the spout 70 is arranged at the unsealed upper end of the container 100, and the body portion 200 of the container 100 and the spout are connected by heat-sealing the sealant layer with respect to the spout 70. An example of a container is shown. In this case, the container 100 includes a body portion 200 and a spout 70, and the packaged object can be taken out from the spout by pressing the body portion 200. In the present specification, such a container is also referred to as a tube container.

The spout 70 shown in FIG. 2 is shown as an example including a tubular spout 72 and a flange 74 extending outward from the peripheral edge of the lower end of the spout 72. The spout may have a tubular spout and a flange extending outward from the peripheral edge of the lower end of the spout, and may be, for example, a spout or the like. The position where the spout is provided is not particularly limited. When the spout is a spout, it may be a so-called center spout or a corner spout.

3 and 4 show another example of the container. The container 110 is composed of two laminated bodies 300 having a body portion 200 as a side sheet and a single laminated body 306 having a bottom sheet. The container 110 is configured by laminating the sealant layers of two laminated bodies 300 serving as side sheets and one laminated body 306 serving as a bottom sheet. The container 110 is formed by sticking a sealing portion 122 obtained by sticking two laminated bodies 300 to be side sheets, a laminated body 306 to be a bottom sheet, and two laminated bodies 300 to be side sheets. It has a seal portion 121 obtained, whereby a bag-shaped form is formed. By having such a configuration, the volume of the accommodating portion 102 can be expanded. The laminated body 306 serving as the bottom sheet has a bent portion 60 generated when the container 110 is manufactured. The unsealed portion at the upper end of the container 110 may be sealed after the container 112 is filled with the packaged object. The

seal portions

122 and 121 are configured by heat-sealing the sealant layers of the laminated body 300 with each other.

It is not essential that the three laminated bodies constituting the container 110 have the same layer structure, and may have different layer structures, for example.

The

containers

100, 110 may accommodate the object to be packaged in the non-sealed portion (sheet portion) surrounded by the sealed

portions

101, 121, 122, and in the present specification, the further sealed container is also referred to as a package. .. The container may be provided with opening means for facilitating opening. The opening means is an opening between a pair of easy-opening processed portions formed of a V-shaped notch formed in a non-sealing portion at the side end portion or a sealing portion 122 at the side end portion and a pair of easy-opening processed portions. It may have a half-cut line that becomes an orbit. Half-cut lines can be formed using a laser. The easy-opening processed portion is not limited to the V-shaped notch, but may be a U-shaped or I-shaped notch, and may have a group of scars.

The laminated body constituting the

above containers

100 and 110 will be described. FIG. 5 is a cross-sectional view schematically showing an example of the laminated body. FIG. 5 shows a cross section of the laminated body along the laminating direction (thickness direction). The laminate 302 has a base material 10, a primer layer 40, an adhesive layer 30, and a sealant layer 20 in this order. The base material 10, the primer layer 40, the adhesive layer 30, and the sealant layer 20 may each have a film-like shape. A printing portion 52 composed of an electrostatic ink composition may be provided on at least a part of the main surface (printing surface) of the primer layer 40 on the sealant layer 20 side. An electrostatic ink layer 50 composed of one or more printing units 52 is provided on the printing surface. In other words, the electrostatic ink layer 50 composed of the printing unit 52 may be provided on at least a part of the pair of main surfaces of the primer layer 40 near the sealant layer 20.

The thickness of the laminated body 302 may be, for example, 15 to 200 μm or 18 to 120 μm.

The base material 10 and the sealant layer 20 may be flexible base materials. Flexible substrates include, for example, biaxially oriented polypropylene (BOPP), polyethylene terephthalate (PET), oriented polypropylene (OPA), unstretched polypropylene (CPP), linear low density polyethylene (LLDPE), and low density. Examples include polyethylene (LDPE).

As the base material 10, for example, a composite film in which a metal foil is bonded on a flexible base material may be used, or a vapor-deposited film or the like in which a metal or the like is vapor-deposited on the flexible base material may be used. The metal or the like may be, for example, a simple substance such as aluminum or a metal oxide such as aluminum oxide. As the base material 10, from the viewpoint of improving the gas barrier property, a vapor-deposited film (transparent vapor-deposited film) or the like in which aluminum, aluminum oxide or the like is vapor-deposited on the PET film can be used. The thickness of the base material 10 may be, for example, 7 to 150 μm, 15 to 90 μm, or 20 to 80 μm.

Examples of the sealant layer 20 include a CPP film, an LLDPE film, and an OPP film. The thickness of the sealant layer 20 may be the same as or different from the thickness of the base material 10, and may be, for example, 7 to 150 μm, 15 to 90 μm, or 20 to 80 μm.

The primer layer 40 may contain a 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-based polymer. By providing the primer layer 40 on the substrate to be printed, it is possible to smoothly print the electrostatic ink composition using a digital printing machine. The coating amount of the resin constituting the primer layer 40 may be, for example, 0.01 to 1.5 g / m ² or 0.05 to 1.0 g / m ² .

The laminate 302 is provided with a printing portion 52 on a main surface (printing surface) of the primer layer 40 opposite to the base material 10. An electrostatic ink layer 50 composed of a plurality of printing units 52 is provided on the printing surface. The electrostatic ink layer 50 is composed of an electrostatic ink composition, and is provided by electrostatic printing using a digital printing machine. The plurality of printing units 52 in FIG. 5 may have the same composition, or may have different colors by having different compositions from each other. The printing portions 52 may be provided so as to be scattered on the primer layer 40, or may be provided so as to cover the entire one surface of the primer layer 40.

The printing unit 52 in the electrostatic ink layer 50 is composed of circular halftone dots of the electrostatic ink composition. In other words, even if it looks uniform in a single color, it has a plain area between the halftone dots. In the electrostatic ink layer 50, circular halftone dots are generally arranged so as to be separated from each other when printing a predetermined area to be printed in a single color, and when printing in two or more colors, the electrostatic ink layer 50 is printed in the first color. It is configured so that the circular halftone dots of the electrostatic ink composition of the second and subsequent colors are arranged so as to partially overlap the halftone dots printed between the halftone dots or the first color. The shade of color on the printed surface can be adjusted by changing the size of the halftone dots, and the color tone on the printed surface can be adjusted by arranging halftone dots of different colors.

The ink coverage of each printing unit 52 constituting the electrostatic ink layer 50 is 500% or less, but may be, for example, 450% or less, or 400% or less. By setting the ink coverage of the printing unit 52 within the above range, the laminating strength of the laminated body is excellent, printing using a plurality of inks is possible, and various printing can be supported. The lower limit of the ink coverage of the printing unit 52 is not particularly limited, but may be, for example, 20% or more, 50% or more, 80% or more, or 100% or more. The ink coverage of the printing unit 52 may be adjusted within the above range, and may be, for example, 20 to 500%, 50 to 400%, 100 to 400%, or 100 to 300%.

In the present specification, the ink coverage (ink coverage) represents the ratio of the halftone dot area per unit area, and the ink coverage when a predetermined area to be printed is uniformly printed in a single color. Is 100%, and the ink coverage of the non-printed area is 0%. When printing with inks of a plurality of colors, the ink coverage of each color is calculated, and the total is used as the ink coverage of the target printing unit and the electrostatic ink layer. The ink coverage is set by a digital printing machine and can be adjusted by specifying a desired value in setting the ink coverage. As the digital printing machine, for example, "Digital printing machine for Indigo 20000 label and packaging" (product name) manufactured by HP can be used. It is also possible to confirm the ink coverage of the electrostatic ink layer in the target laminate by observing the printed surface of the container or laminate with an optical microscope.

Since the printing portion 52 is composed of circular halftone dots of the electrostatic ink composition, even when the ink coverage is 100%, the surface of the electrostatic ink layer 50 on the sealant layer 20 side is covered. The main surface of the primer layer 40 can be confirmed by observing with an optical microscope or the like. That is, even if the ink coverage is 100%, the primer layer 40 and the adhesive layer 30 can be directly adhered to each other. On the other hand, as the ink coverage becomes larger, the proportion of the primer layer 40 on the adhesive surface (interface) between the printing portion 52 and the adhesive layer 30 tends to decrease. When a conventional adhesive is used, as the ink coverage increases, the adhesive force at the interface between the electrostatic ink layer and the primer layer or the interface between the electrostatic ink layer and the adhesive layer decreases, and the laminate as a laminate is used. In some cases, the strength may not be as strong as expected. On the other hand, in the laminated body according to the present disclosure, by using the adhesive composition described later, sufficient laminating strength can be exhibited even when the ink coverage is large. In the laminate according to the present disclosure, expansion of the laminate 300, etc., particularly during heat treatment, can be prevented by using the adhesive composition described later.

The amount of ink applied to the main surface (printing surface) of the primer layer 40 on the sealant layer 20 side is, for example, 0.5 g / m ² or more, 1.0 g / m ² or more, 2.0 g / m ² or more, or 3. It may be 0 g / m ² or more. When the amount of the ink applied is within the above range, it is possible to obtain a variety of print expressions composed of a plurality of colors. The amount of ink applied on the main surface of the primer layer 40 on the sealant layer 20 side may be, for example, 8.0 g / m ² or less, or 6.0 g / m ² or less. When the ink application amount is within the above range, a decrease in adhesive strength at the interface between the electrostatic ink layer 50 and the primer layer 40 or the interface between the electrostatic ink layer 50 and the adhesive layer 30 is more sufficiently suppressed. can. The ink application amount in the present specification means the total amount (solid content amount) of the ink composition used for printing, and means the total value when printing in multiple colors.

FIG. 6 is a cross-sectional view showing another example of the laminated body. The laminate 304 of FIG. 6 is the laminate 302 of FIG. 5 in that one surface of the primer layer 40 is entirely covered with an electrostatic ink layer 51 (a printing portion 52 formed over the entire printing surface). Is different from. That is, in the laminated body 304, the coating ratio of the electrostatic ink layer 51 to the main surface of the primer layer 40 is 100 area%. By using the adhesive composition described later, even a configuration such as a laminated body 304 in which it is difficult to secure a sufficient direct adhesive area between the primer layer 40 and the adhesive layer 30 has sufficient adhesive strength. However, delamination and the like in the laminated body 304 are suppressed.

In the

laminates

302 and 304, the electrostatic ink composition constituting the electrostatic ink layers 50 and 51 is an ink composition used for liquid electrophotographic printing, that is, electrostatic printing, and is a base material such as paper and plastic. Or it is printed on the primer layer. The electrostatic ink composition may contain a colorant such as a pigment and a dye, and a resin. The electrostatic ink composition may also further comprise a carrier fluid or carrier liquid. The electrostatic ink composition may include, for example, a charge director, a charge adjuvant, a surfactant, a viscosity modifier, an emulsifier and other additives.

Examples of the colorant include cyan pigments, magenta pigments, yellow pigments, black pigments and the like. From the viewpoint of facilitating digital printing, a resin having a relatively low melting point can be used as the resin. The relatively low melting point may be, for example, 100 ° C. or lower. Examples of the resin include thermoplastic resins such as ethylene acrylic acid copolymer, propylene acrylic acid copolymer, ethylene methacrylic acid copolymer, propylene methacrylic acid copolymer, and ethylene vinyl acetate copolymer. The resin preferably contains at least one of an ethylene acrylic acid copolymer and an ethylene methacrylic acid copolymer.

Examples of the carrier fluid and the carrier liquid include hydrocarbons, silicone oils, vegetable oils and the like. Examples of the hydrocarbon include aliphatic hydrocarbons, branched-chain aliphatic hydrocarbons, and aromatic hydrocarbons. The electrostatic ink composition may be substantially free of carrier fluids and carrier liquids when printed on a substrate. The carrier fluid and carrier liquid may be removed, for example, by an electrophoresis process during printing or evaporation. By the removal operation, substantially only the solid content is transferred onto the substrate or the primer layer.

The charge director has the function of maintaining a sufficient electrostatic charge on the particles contained in the electrostatic ink composition. Examples of the charge director include a metal salt of fatty acid, a metal salt of sulfosuccinate, a metal salt of oxyphosphate, a metal salt of alkylbenzene sulfonic acid, a metal salt of aromatic carboxylic acid, and a metal salt of aromatic sulfonic acid. Ionic compounds, as well as dual ionic and nonionic compounds such as polyoxyethyleneated alkylamines, lecithin, polyvinylpyrrolidone, and organic acid esters of polyhydric alcohols.

The charge adjuvant has the effect of increasing or stabilizing the charge of the particles contained in the electrostatic ink composition. Examples of the charge adjuvant include barium petronate, calcium petronate, naphthenic acid Co salt, naphthenic acid Ca salt, naphthenic acid Cu salt, naphthenic acid Mn salt, naphthenic acid Ni salt, naphthenic acid Zn salt, and naphthenic acid Fe salt. Examples thereof include stearic acid Ba salt, stearic acid Co salt, stearic acid Pb salt, stearic acid Zn salt, stearic acid Al salt, stearic acid Cu salt, stearic acid Fe salt, and metal carboxylate.

The electrostatic ink layers 50 and 51 may contain crosslinked products crosslinked by components contained in at least one of the adhesive layer 30 and the primer layer 40. By including the crosslinked product, the strength of the electrostatic ink layers 50 and 51 themselves, the adhesive strength between the printed surface of the primer layer 40 and the electrostatic ink layer 50, and the adhesive strength between the electrostatic ink layer 50 and the adhesive layer 30 The adhesive strength can be further improved.

The printing portion 52 of the electrostatic ink composition and the adhesive layer 30 are adhered to each other. That is, the printing portion 52 serves as an adhesive surface with the adhesive layer 30, and the electrostatic ink composition and the adhesive composition are in direct contact with each other.

The adhesive composition contains an epoxy compound. The epoxy compound reacts with the components constituting the electrostatic ink composition, the adhesive layer and the primer layer and cures, so that the adhesive layer and the printed surface of the primer layer can be firmly adhered to each other. The epoxy compound itself may be cured to form a cured product. The adhesive composition may further contain at least one selected from the group consisting of polyols and polyisocyanates, may further contain polyols, may further contain polyisocyanates, and may further contain polyols and polyisocyanates. The adhesive composition may contain a polyol, a polyisocyanate, and an epoxy compound. At least a part of these three components (polyester, polyisocyanate, and epoxy compound) may react with each other and be cured to form a cured product. That is, the adhesive composition may be composed of at least one of an adhesive composition containing a polyol, a polyisocyanate and an epoxy compound and a cured product thereof, and the adhesive layer 30 is an adhesive composition, a cured product thereof. Alternatively, it may be composed of a mixture thereof. Polyols and polyisocyanates react as a main agent and a curing agent, respectively, to produce polyurethane (polyurethane adhesive).

The epoxy compound may be a compound having one or two or more epoxy groups in one molecule. From the viewpoint of further increasing the adhesive strength of the adhesive layer 30 in a high temperature environment, it may have epoxy groups at both ends. Examples of the epoxy compound include a glycisyl ether type epoxy compound, a glycisyl amine type epoxy compound, a glycidyl ester type epoxy compound, and an alicyclic epoxy compound (cyclic aliphatic epoxy compound).

The epoxy compound in the adhesive composition can penetrate into layers adjacent to the adhesive layer (eg, primer layer, electrostatic ink layer, sealant layer, etc.). By penetrating in this way, the adhesion between each layer after curing of the epoxy compound can be further improved. In this case, the primer layer, the electrostatic ink layer, and the sealant layer include at least one of an epoxy compound and a cured product thereof (epoxy resin, etc.). The molecular weight of the epoxy compound may be, for example, 500 or less, 450 or less, or 400 or less. When the molecular weight of the epoxy compound is within the above range, the epoxy compound can be more sufficiently permeated into the electrostatic ink composition constituting the electrostatic ink layer. The lower limit of the molecular weight of the epoxy compound may be, for example, 98 or more.

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

Examples of the monofunctional alicyclic epoxy compound having one epoxy group in one molecule include 3,4 epoxy cyclohexylmethyl methacrylate and 1,2-epoxy-4-vinylcyclohexane. Bifunctional epoxy compounds having two epoxy groups in one molecule include, for example, 3', 4'-epoxycyclohexylmethyl-3,4 epoxycyclohexanecarboxylate, and bis (3,4-epoxycyclohexylmethyl) adipate. , And 4-vinylcyclohexene dioxide and the like. Further, as an epoxy compound having one or more epoxy groups in one molecule, 1,2-epoxy-4- of 2,2-bis (hydroxymethyl) -1-butanol represented by the following general formula (I). Examples include (2-oxylanyl) cyclohexane adducts.

In the above general formula (I), n may be an integer of 1 to 4.

The epoxy compound preferably contains a bifunctional alicyclic epoxy compound. By being bifunctional, it is possible to increase the cross-linking points between the electrostatic ink composition and the primer resin, promote the curing reaction of the adhesive, and facilitate curing. When the adhesive composition further contains polyisocyanate, the epoxy compound can suppress the reaction with polyisocyanate due to steric hindrance because it is an alicyclic compound. Therefore, it can be stably cured, and the adhesion between the printed portion 52 and the adhesive layer 30 can be sufficiently excellent.

The polyol has two or more hydroxyl groups in one molecule, and for example, the number average molecular weight may be 400 or more. The number average molecular weight of the polyol may be, for example, 10,000 or less.

The polyol may contain, for example, at least one selected from the group consisting of polyester polyols and polyether polyols. Of these, the polyol may contain a polyester polyol or may contain an aliphatic polyester polyol from the viewpoint of sufficiently increasing the adhesive strength of the adhesive layer 30 in a high temperature environment.

The polyester polyol can be obtained, for example, by a condensation reaction of a polyhydric alcohol with a polybasic acid, an alkyl ester of a polybasic acid, an acid anhydride of a polybasic acid, or an acid halide of a polybasic acid, or an ester exchange reaction. ..

Examples of the polyhydric alcohol include low molecular weight diols, low molecular weight triols, low molecular weight polyols having four or more hydroxyl groups, and the like.

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 thereof include heptane and 2-ethyl-2-butyl-1,3-propanediol.

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. , Trimethylolethane, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3- (hydroxymethyl) pentane, and 2,2-bis (hydroxymethyl) -3-butanol. And so on.

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 the alkyl ester of polybasic acid include methyl ester of polybasic acid and ethyl ester of polybasic acid. Examples of the acid anhydride of the polybasic acid include an acid anhydride derived from the polybasic acid. More specifically, the acid anhydrides of polybasic acids include succinic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, 2-alkyl anhydride (12-18 carbon atoms) succinic anhydride, and tetrahydrophthalic anhydride. And trimellitic anhydride and the like.

Examples of the acid halide of the polybasic acid include the above-mentioned alkyl ester of the polybasic acid or the acid halide derived from the acid anhydride of the polybasic acid. More specific examples of the polybasic acid acid halide include oxalic acid dichloride, adipic acid dichloride, and sebatic acid dichloride.

Examples of the polyether polyol include polyalkylene oxides and the like. The polyether polyol may be, for example, one obtained by an addition reaction of an alkylene oxide such as ethylene oxide and / or propylene oxide using a low molecular weight polyol as an initiator. More specifically, the polyether polyol includes polyethylene glycol, polypropylene glycol, polyethylene polypropylene glycol (random or block copolymer) and the like. Examples of the polyether polyol include polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran and the like.

Polyisocyanate has two or more isocyanate groups in one molecule. Examples of the polyisocyanate include a polyisocyanate monomer, a polyisocyanate derivative, and an isocyanate group-terminated prepolymer. The adhesive composition may contain a plurality of types of polyisocyanates that are different from each other. The molar ratio (NCO / OH) of the isocyanate group contained in the polyisocyanate to the hydroxyl group of the polyol may be, for example, 0.5 to 10. Such an adhesive composition can form a cured product having high adhesive strength and excellent flexibility.

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

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), and 1 , 5-Pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisamethylene methyl capate, etc. Can be mentioned.

Examples of the aromatic aliphatic polyisocyanate include xylylene diisocyanate derivatives. Examples of the xylylene diisocyanate derivative include xylylene diisocyanate (1,3-xylylene diisocyanate or 1,4-xylylene diisocyanate) (XDI) and tetramethylxylylene diisocyanate (1,3-tetramethylxylylene diisocyanate). , Or 1,4-tetramethylxylylene diisocyanate) (TMXDI), ω, ω'-diisocyanate-1,4-diethylbenzene, and polyol modification of xylylene diisocyanate obtained by the reaction of xylylene diisocyanate with trimethylolpropane. The body etc. can be mentioned.

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

Examples of the alicyclic polyisocyanate include 1,3-cyclopentanediisocyanate, 1,3-cyclopentenediisocyanate, cyclohexanediisocyanate (1,4-cyclohexanediisocyanate, 1,3-cyclohexanediisocyanate), and 3-isocyanatomethyl-3. , 5,5-trimethylcyclohexylisocyanate (isophorone diisocyanate) (IPDI), methylcyclohexanediisocyanate (methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate), norbornandiisocyanate (NBDI) and the like. ..

Examples of the polyisocyanate derivative include a multimer of the above-mentioned polyisocyanate monomer, an allophanate modified product, a polyol modified product, a polyol modified product produced by the reaction of the monomer with alcohols, a biuret modified product, and a urea modified product. , Oxadiazine trione modified product, carbodiimide modified product, uretdione modified product, ureton imine modified product and the like.

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

In the adhesive composition, the content of the epoxy compound with respect to 100 parts by mass of the polyol is, for example, 3 to 25 parts by mass, 6 to 25 parts by mass, or 8 to 8 to 5 parts by mass from the viewpoint of achieving both high adhesive strength and excellent shear suppressing power. It may be 20 parts by mass. If the content of the epoxy compound is excessive, the excellent shear-suppressing power tends to be impaired. That is, when the adhesive layer 30 is formed, the adhesive surface may shift or the adhesive composition may protrude. If the amount of the epoxy compound is too small, the adhesive strength tends to decrease under high temperature hot water treatment conditions.

In the adhesive composition, the content of polyisocyanate with respect to 100 parts by mass of the polyol is, for example, 10 to 50 parts by mass and 15 to 35 parts by mass from the viewpoint of sufficiently increasing the sealing strength and the adhesive strength under high temperature hot water treatment conditions. It may be parts or 20 to 30 parts by mass.

The molar ratio of the epoxy group contained in the epoxy compound to the isocyanate group contained in the polyisocyanate may be, for example, 0.5 to 10, 1.5 to 9, or 2.0 to 6.5. This makes it possible to maintain a sufficiently high adhesive strength under high temperature hot water treatment conditions.

The adhesive composition constituting the adhesive layer 30 may contain an optional component such as an additive in addition to the above-mentioned components. Additives include, for example, antioxidants, UV absorbers, light stabilizers, fillers, silane coupling agents, epoxy resins, catalysts, coatability improvers, leveling agents, nucleating agents, lubricants, mold release agents, etc. Examples thereof include defoaming agents, plastic agents, surfactants, pigments, dyes, organic fine particles, inorganic fine particles, fungicides, flame retardants and the like. The adhesive composition may contain a solvent such as an organic solvent.

The adhesive composition adheres the printing portion 52 on which the electrostatic ink composition is printed and the sealant layer 20. Any layer may be provided between the adhesive layer 30 and the sealant layer 20. The

laminates

302 and 304 may further have a barrier layer or the like between the adhesive layer 30 and the sealant layer 20, for example. In this case, the adhesive composition adheres the printed portion 52 to an arbitrary layer (for example, a barrier layer or the like). When the adhesive composition contains a polyol and a polyisocyanate, it can form a urethane bond by reacting with the polyol and the polyisocyanate, and can more fully exhibit the function as an adhesive. Since the formation of the urethane bond proceeds smoothly even in the coexistence of the epoxy compound, the printed portion 52 and the sealant layer 20 or any layer can be bonded with a sufficiently higher adhesive strength.

The adhesive composition may have a function of cross-linking the electrostatic ink compositions forming the electrostatic ink layers 50 and 51 together with the formation of urethane bonds. Thereby, the adhesive strength between the printed surface and the sealant layer 20 or any layer can be further improved.

When the coverage ratio of the primer layer 40 to the main surface (printing surface) of the primer layer 40 by the electrostatic ink layer 50 is high, or when the ink coverage of the printing section 52 (electrostatic ink layers 50 and 51) is high, the electrostatic ink is generally used. The adhesive strength between the layer 50 and the adhesive layer 30 tends to decrease, but in the case of the above-mentioned adhesive composition, sufficient adhesive strength can be exhibited. Further, when the coating ratio of the primer layer 40 to the main surface of the primer layer 50 by the electrostatic ink layer 50 or the ink coverage ratio in the printing unit 52 (electrostatic ink layers 50 and 51) becomes high, it is contained in the adhesive composition accordingly. By increasing the content of the epoxy compound, the epoxy compound can be sufficiently permeated into the electrostatic ink layers 50 and 51 composed of the electrostatic ink composition, and the decrease in adhesive strength can be further suppressed. The permeated epoxy compound has an effect of increasing the strength of the electrostatic ink composition (electrostatic ink layers 50, 51) by cross-linking the electrostatic ink composition. Therefore, even when the ink coverage of the printing unit 52 is high and heat treatment such as retort heat treatment is performed, the decrease in adhesive strength can be sufficiently suppressed.

The adhesive composition can maintain high adhesive strength even after heat treatment, but also has excellent pot life. Therefore, it is also excellent in workability such as coating and laminating when adhering the printed surface and the base material. The adhesive composition may contain an epoxy compound, a polyol and a polyisocyanate forming urethane, and an epoxy compound, and at least a part of these may be a cured product to form an adhesive layer. This can reduce the number of layers constituting the laminate 300 as compared with the case where the adhesive layer containing only polyurethane and the epoxy coating layer are separately provided. Therefore, for example, when a laminate is produced by roll-to-roll, the meandering of the roll after aging and the generation of wrinkles due to blocking or the like can be suppressed. In addition, the aging process after coating can be reduced to improve manufacturing efficiency.

In the

laminates

302 and 304 in which the electrostatic ink layers 50 and 51 and the adhesive layer 30 are in direct contact with each other on the printing surface, the epoxy compound contained in the adhesive composition may be an epoxy compound and / or a polyisocyanate or the like. The components sufficiently penetrate into the electrostatic ink layers 50 and 51. As a result, the electrostatic ink compositions constituting the electrostatic ink layers 50 and 51 can be crosslinked, and the strength of the electrostatic ink compositions (electrostatic ink layers 50 and 51) can be improved. In addition, the adhesive strength between the layers can be improved. Further, even when the printed surface includes a plain portion (transparent portion) without the electrostatic ink layer 50 as shown in FIG. 5, since the epoxy compound is contained in the adhesive layer, stickiness can be eliminated. can. On the other hand, if an epoxy coating layer is provided separately from the adhesive layer 30, when a plain portion is included on the printed surface, the epoxy compound becomes excessive in the vicinity of the plain portion, and stickiness is likely to occur. In this way, the laminated body 300 can eliminate stickiness while adhering the printed surface including the plain portion on which the printed portion 52 is not formed with high adhesive strength.

As described above, the

laminates

302 and 304 can sufficiently secure the adhesive strength between the electrostatic ink layers 50 and 51 and the base material 10, the primer layer 40, and the adhesive layer 30, so that the bent portion 60 Can also form a container in which peeling between the electrostatic ink layers 50 and 51, the base material 10, the primer layer 40, and the adhesive layer 30 is suppressed. In such a container, since the adhesive state between the layers is maintained even in the bent portion 60, the occurrence of misalignment of the printed surface is suppressed, and the print information in the body portion 200 including the bent portion 60 is printed. Can be maintained in the initial state with the above. Even in the process of using the container, for example, even when a new bent portion is generated due to bending of the container or the like, the adhesive state between the layers is maintained, so that the function as a container (for example, barrier property, etc.) Can be maintained for the duration of use. Similarly, the breakage of the container itself and the deterioration of printed information can be suppressed over the period of use. In such a container, even when the bent portion has a printed surface, the occurrence of peeling and the like between the layers is suppressed, so that the information written on the printed surface can be read and the appearance is as good as possible. It is useful as a container for important foods and drinks and hygiene products. However, the application is not limited to these. For example, since it is excellent in adhesive strength and sealing strength even after high-temperature hot water treatment and retort heat treatment, it may be used as a material for constituting a retort container, a microwave oven-compatible container, and a boiling container.

The laminate according to the modified example may have a primer layer 40 on each of the facing surfaces of the base material 10 and the sealant layer 20. Further, between the base material 10 and the sealant layer 20, from the viewpoint of improving the gas barrier property and the water vapor barrier property of the

laminates

302 and 304, the space between the base material 10 and the primer layer 40 and / or the sealant layer 20 At least one of a metal layer such as an aluminum foil and a resin layer such as a nylon film may be provided between the adhesive layer 30 and the like.

Specific examples of the layer structure of the laminated body are illustrated below. In each example, the left end corresponds to the base material 10 and the right end corresponds to the sealant layer 20, which means that the layers are laminated in order from left to right. The first adhesive layer is the adhesive layer 30, and the second adhesive layer and the third adhesive layer may be conventional adhesive layers.

(1) Transparent vapor-deposited PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / CPP film (non-stretched polypropylene film)
(2) PET film / primer layer / electrostatic ink layer / first adhesive layer / aluminum layer / second adhesive layer / nylon layer / third adhesive layer / CPP film (non-stretched polypropylene film)
(3) PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / CPP film (non-stretched polypropylene film)
(4) PET film / primer layer / electrostatic ink layer / first adhesive layer / aluminum layer / second adhesive layer / polyethylene film

In each of the above specific examples, an arbitrary layer may be provided at an arbitrary position between the first adhesive layer and the sealant layer 20. (1) and (2) are preferably used as a laminate for retort pouch, (3) as a laminate for a microwave oven, and (4) as a laminate whose contents are supplements or face masks. However, the application is not limited to the above.

The above-mentioned laminate can be prepared by, for example, the following method. An embodiment of a method for manufacturing a laminate will be described below. In an example of the method for manufacturing the laminated body, the laminated body 302 shown in FIG. 5 is manufactured. First, a step of forming a primer layer 40 on one surface of a film-like base material 10 and a step of printing an electrostatic ink composition on the primer layer 40 to form an electrostatic ink layer 50 composed of a printing unit 52. A step of bonding the electrostatic ink layer 50 and one surface of the sealant layer 20 using the above-mentioned specific adhesive composition.

The primer layer 40 may be formed on one surface of the base material 10 by flexographic printing, gravure printing, or the like. In the primer layer 40, the resin raw material may be crosslinked with a crosslinking agent. Cross-linking may be performed by irradiating with ionizing radiation such as ultraviolet light, heating, electron beam, and non-ionizing radiation such as microwave radiation.

The electrostatic ink composition can be printed by electrostatic printing using a digital printing machine.

Adhesion of the electrostatic ink layer 50 and one surface of the sealant layer 20 with the adhesive composition can be performed by laminating. Lamination can be performed using any device. In some cases, the epoxy compound contained in the adhesive composition penetrates the electrostatic ink composition and the primer layer 40 in which the epoxy compound and / or the polyisocyanate constitutes the electrostatic ink layer 50, and the electrostatic ink composition and the primer are used. A cross-linking reaction may be carried out with the components contained in the layer 40. As a result, the strength of the electrostatic ink layer 50 is improved, and the laminated body 300 in which the interfaces of the layers are sufficiently bonded can be obtained. At the time of laminating, at least a part of the adhesive composition may be cured to become a cured product. In this way, the laminate 302 including the base material 10, the primer layer 40, the electrostatic ink layer 50, the adhesive layer 30, and the sealant layer 20 in this order can be manufactured. The laminated body 304 and the laminated body according to the modified example can also be manufactured in the same manner as the laminated body 302.

The

laminates

302 and 304 produced in this way have the configurations and properties as described in these embodiments. The description of the

laminated bodies

302 and 304 and their modified examples also applies to the description of the above-described embodiment of the manufacturing method.

[Packaging bag for heating]
FIG. 7 is a plan view showing an example of the packaging bag 120 (packaging bag for heating) according to the embodiment. As shown in FIG. 7, the packaging bag 120 is composed of a laminate 300 having a base material, a primer layer, an electrostatic ink layer, an adhesive layer, and a sealant layer in this order. The structure of the laminated body 300 will be described later. The packaging bag 120 may be, for example, a bag that is sealed while containing an object to be packaged such as food and drink. The packaging bag 120 may or may not have a bent portion.

The packaging bag 120 is a packaging bag for heating. The packaging bag for heating is a packaging bag that is assumed to be heat-treated while containing the object to be packaged. The heat treatment includes "retort heat treatment", "boil heat treatment", "microwave oven heat treatment" and the like. The retort heat treatment is, for example, a process of pressurizing and heating in a state where the contents are filled and heat of 100 ° C. or higher is applied, and for example, a steam type or the like can be adopted. The boil heat treatment is a process of heating the packaging bag in heated water (hot water), and is heated up to 100 ° C. Further, the microwave oven heat treatment is a heat treatment using a so-called microwave oven, and is a process of generating heat of a substance containing water by vibrating and rotating water molecules by electromagnetic waves (microwaves). Both treatments are often performed for the purpose of sterilizing the packaging bag or the object to be packaged.

The packaging bag 120 is configured by laminating the sealant layers of the pair of laminated bodies 300. The packaging bag 120 has a sealing portion 101 in which the peripheral edges of a pair of film-shaped substantially rectangular laminated bodies 300 are bonded (sealed), and an accommodating portion 124 formed between the pair of laminated bodies 300 by the sealing portion 101. And. The seal portion 101 is formed on a pair of side end portions, lower end portions, and upper end portions of the rectangular packaging bag 120. As described above, in the packaging bag 120, the seal portion 101 is formed over the entire circumference of each of the pair of laminated bodies 300 in a state where the sealant layers are overlapped with each other in a plan view. The storage unit 124 may contain, for example, an object to be packaged (for example, food and drink). In the following embodiment, the packaged object 400 may be particularly referred to as a package containing and sealed object to be packaged. The sealing portion 101 at the lower end may be sealed after the container 124 is filled with the object to be packaged. The seal portion 101 is configured by heat-sealing the sealant layers of the laminated body 300 with each other.

It is not essential that the pair of laminated bodies 300 constituting the packaging bag 120 have the same layer structure, and for example, the pair of laminated bodies may have different layer structures.

The packaging bag 120 may be provided with an opening means 140 for facilitating opening. The opening means 140 is a half-cut line that serves as an opening trajectory between a pair of easy-opening processed portions 144 formed of V-shaped notches formed in the sealing portion 101 at the side end and a pair of easy-opening processed portions 144. It has 141. The half-cut line 141 can be formed using, for example, a laser. The easy-open processing portion 144 is not limited to the V-shaped notch, and may be a U-shaped or I-shaped notch, and may have a group of scars.

The procedure for manufacturing the packaging bag 120 and the packaging body 400 using the laminated body 300 will be described below. A pair of laminated bodies 300 molded into a predetermined shape are prepared. The sealant layers provided on one surface of each laminated body 300 are opposed to each other, and the sealant layers are adhered to each other. At this time, by forming the seal portion 101 with respect to the pair of side end portions and the lower end portion (or upper end portion), the seal portion 101 in a state where three of the four sides are closed is formed, and the inside thereof. A non-sealed portion is formed on the surface. As a result, a packaging bag 130 in which only the upper end portion (or only the lower end portion) is not sealed as shown in FIG. 8 is obtained.

Next, the packaged object is filled inside the storage portion 132 of the packaging bag 130 from the upper end portion (or lower end portion) in the unsealed state. After that, the sealant layers of the laminated body 300 are adhered to each other at the upper end portion (or lower end portion) in the unsealed state to form the seal portion 101 at the upper end portion (or lower end portion). As a result, the packaging body 400 including the packaging bag 120 and the object to be packaged contained therein can be manufactured.

As described above, the above-mentioned packaging bag 120 is a packaging bag that can be used in a state in which an object to be packaged is contained, that is, when it is assumed that heat treatment is performed as a package body 400. According to the above-mentioned heat treatment, the packaging bag 120 itself is heated, so that resistance to heat is required. Further, in any of the heat treatments, water molecules are present in the vicinity in a high temperature environment, so that water resistance at a high temperature is required. Further, in the packaging bag 120, since the heat treatment is performed in the state where the contents to be contained are contained, it is considered that the seal portion 101 is particularly susceptible to the heat treatment. In response to these demands, the packaging bag 120 improves the water resistance and heat resistance of the laminated body by forming each layer constituting the laminated body 300 by combining specific materials. Further, as the packaging bag 120, by making a part of the structure of the laminated body 300 in the sealing portion 101 satisfy a specific condition, damage to the packaging bag 120 in the sealing portion 101 particularly during the heat treatment can be prevented. ..

Next, as the laminate 300 constituting the packaging bag 120, the

laminates

302 and 304 described as the constituent materials of the container can be used, and the description can be applied unless otherwise specified. For example, as the material or the like constituting each layer, the material or the like exemplified in the explanation of the corresponding layer in the above-mentioned explanation about the container can be used. Hereinafter, an example in which the above-mentioned laminated body 302 is used as the laminated body 300 will be described.

The primer layer 40 may contain a resin. When the packaging bag 120 is used for heating, the resin preferably contains a polyethyleneimine resin. In addition to the polyethyleneimine resin, the primer layer 40 includes, for example, a polyvinyl alcohol resin, a cellulose resin, a polyester, a polyamine, a polyamide resin, a polyurethane, a polyacrylic polymer, a hydroxyl group-containing resin, a carboxyl group-containing resin, and an amine-based polymer. Etc. may be further contained. By providing the primer layer 40 containing the polyethyleneimine resin on the base material to be printed, the water resistance is improved and the laminated body 302 suitable for the heat treatment can be produced. The content of the polyethyleneimine resin in the primer layer 40 may be 80% by mass or more, 90% by mass or more, or 97% by mass or more. The coating amount of the resin constituting the primer layer 40 may be, for example, 0.01 to 1.5 g / m ² or 0.05 to 1.0 g / m ² .

The laminate 302 is provided with a printing portion 52 on one main surface (printing surface) closer to the sealant layer 20 among the pair of main surfaces of the primer layer 40. An electrostatic ink layer 50 is provided on the printing surface. The electrostatic ink layer 50 is composed of an electrostatic ink composition, and is provided by electrostatic printing using a digital printing machine. The plurality of printing units 52 in FIG. 5 may have the same composition, or may have different colors by having different compositions from each other. The electrostatic ink layer 50 may be composed of printing units 52 provided so as to be scattered on the primer layer 40, or may be formed by printing units 52 provided so as to cover the entire one side of the primer layer 40. It may be configured.

When the packaging bag 120 is used for heating, the ink coverage of each printing unit 52 constituting the electrostatic ink layer 50 may be 100 to 400%. By setting the ink coverage of the printing unit 52 within the above range, the laminate strength of the laminate is excellent, printing using a plurality of inks is possible, and various printing can be supported.

As described above, the laminate 300 (302, 304) can sufficiently secure the adhesive strength between the electrostatic ink layers 50 and 51 and the base material 10, the primer layer 40, and the adhesive layer 30. Therefore, when the laminate 300 is used as a packaging bag for heating and heat-treated, the electrostatic ink layers 50 and 51 are separated from the base material 10, the primer layer 40, and the adhesive layer 30. Is suppressed.

When the packaging bag 120 is used for heating, a specific example of the layer structure of the laminated body is illustrated below. In each example, the left end corresponds to the base material 10 and the right end corresponds to the sealant layer 20, which means that the layers are laminated in order from left to right. The first adhesive layer is the adhesive layer 30, and the second adhesive layer and the third adhesive layer may be conventional adhesive layers.

(5) Transparent vapor-deposited PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / CPP film (non-stretched polypropylene film)
(6) PET film / primer layer / electrostatic ink layer / first adhesive layer / aluminum layer / second adhesive layer / nylon layer / third adhesive layer / CPP film (non-stretched polypropylene film)
(7) Nylon layer / Primer layer / Electrostatic ink layer / First adhesive layer / LLDPE (linear low density polyethylene) film (8) PET film / Primer layer / Electrostatic ink layer / First adhesive layer / Nylon layer / second adhesive layer / CPP film

In each of the above specific examples, an arbitrary layer may be provided at an arbitrary position between the first adhesive layer and the sealant layer 20. The above (5) and (6) are mainly used for packaging bags that are expected to be subjected to retort heat treatment, and (7) are mainly used for packaging bags that are expected to be subjected to boil heat treatment, and (8). Is mainly used for packaging bags that are expected to be subjected to microwave oven heat treatment. However, the application is not limited to the above.

The above-mentioned laminate can be prepared based on the same manufacturing method as the above-mentioned laminate as a constituent material of the container.

[Action]
As described in the above embodiment, the packaging bag 120 (the packaging bag for heating) according to the present embodiment is a laminate in which the base material 10, the primer layer 40, the adhesive layer 30, and the sealant layer 20 are laminated in this order. It is composed of 300. Further, the adhesive layer 30 contains at least one of an adhesive composition containing an epoxy compound and a cured product of the adhesive composition. Further, from the viewpoint of improving water resistance, the primer layer 40 may contain a polyethyleneimine resin.

The electrostatic ink composition produced by a digital printing machine tends to be inferior in heat resistance and strength to other inks. Therefore, when an attempt is made to apply a laminate having an electrostatic ink layer derived from an electrostatic ink composition to a packaging bag for heat treatment, the packaging bag may be damaged or the like. On the other hand, according to the above configuration, the curing of the adhesive composition containing the epoxy compound suppresses the deformation of the laminated body due to heating or the like, so that the heating has sufficient resistance to heat treatment. A packaging bag is obtained. In addition, when a primer layer containing a polyethyleneimine resin is provided, water resistance is also improved, and more sufficient resistance to heat treatment in an environment containing a large amount of water, such as boil heat treatment or retort heat treatment, can be obtained. Be done.

Further, the packaging bag 120 (packaging bag for heating) includes a sealing portion 101 that adheres the sealant layers 20 of the two laminated bodies 300 to each other on the outer peripheral portion. Further, in the seal portion 101, the ink coverage of the electrostatic ink layer 50 may be 300% or less. Since the seal portion 101 is a region where heat-bonding processing such as heat sealing is performed, the possibility of damage is higher than in other regions. On the other hand, by setting the ink coverage of the electrostatic ink layer within the above range, it is possible to secure more sufficient resistance to the heat treatment of the sealed portion as well, and to have stronger resistance to the heat treatment. A packaging bag for heating can be obtained.

The epoxy compound can be an embodiment containing a bifunctional alicyclic epoxy compound. By being bifunctional, such an epoxy compound increases the number of cross-linking points with the electrostatic ink composition and firmly adheres to the printed surface.

Further, the adhesive composition may further contain a polyol, the polyol may contain an aliphatic polyester polyol, and the epoxy compound may include one having an epoxy group at both ends. Such an adhesive layer 30 has high adhesive strength particularly even in a high temperature environment. Therefore, when the packaging bag is produced by combining the laminated bodies 300, it is possible to sufficiently prevent the electrostatic ink composition from breaking or the packaging bag from being damaged.

The adhesive composition may further contain a polyisocyanate, and the polyisocyanate may contain a xylylene diisocyanate derivative. Such polyisocyanates and polyols are excellent in reactivity. As a result, the curability of the adhesive composition is improved, so that deformation of the laminate 300 and the packaging bag can be suppressed.

The laminate 300 (302, 304) and the packaging bag produced in this manner have the configurations and properties as described in these embodiments. The description of the laminate 300, the packaging bag, and the modifications thereof also applies to the description of the above-described embodiment of the manufacturing method.

Although some embodiments have been described above, mutual explanations can be applied to common configurations. Further, the present disclosure is not limited to the above embodiment.

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

(Example I-1)
[Preparation of laminate]
As a base material, an alumina-deposited PET film (manufactured by Toppan Printing Co., Ltd., trade name: GLARH12, 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 to form a primer layer. Aqueous polyethyleneimine was applied so that the amount applied was 0.10 to 0.18 g / m ² .

Predetermined printing was performed on the surface of the primer layer using a digital printing machine (manufactured by HP, Digital printing machine for Indigo 20000 label and packaging). As the electrostatic ink composition, an electrostatic ink composition (HP Indigo electro ink) containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid was used. As the colors of the electrostatic ink composition, yellow (Y), magenta (M) and cyan (C) were used as shown in Table 1. A plurality of samples having different colors and ink coverage of the electrostatic ink composition were prepared. The ink coverage was as shown in Table 1. Each ink coverage was adjusted according to the settings of the digital printing machine. The total ink coverage was 200%.

An aliphatic polyester polyol (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takelac A626, hereinafter sometimes referred to as "(A)") as a main agent, and a polyisocyanate (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takenate A50) as a curing agent. , Hereinafter referred to as "(B)"), 3', 4'-epoxycyclohexylmethyl-3,4 epoxycyclohexanecarboxylate as an epoxy compound (hereinafter, may be referred to as "C"), and. , Ethyl acetate was blended as a solvent to prepare an adhesive composition having a solid content concentration of 36.5% by mass. The structure of this epoxy compound is as shown in the following formula (1). The mass-based compounding ratio (mass-based) of each component was (A) :( B) :( C) = 8: 1: 0.28.

The adhesive composition prepared as described above was applied to the printed surface on which the electrostatic ink composition was printed using a dry laminating apparatus to form an adhesive layer. The coating amount of the adhesive composition was 4.0 g / m ² .

A laminated film was prepared by laminating a nylon film and a non-stretched polypropylene film with a commercially available adhesive. Using the dry laminating apparatus, the adhesive layer on the base material and the nylon film of the laminated film were opposed to each other, and the nylon film and the adhesive layer were bonded to each other to obtain a laminated body. The curing time (aging) was set at 40 ° C. for 2 days.

(Comparative Example I-1)
A laminate was prepared in the same manner as in Example I-1 except that the epoxy compound (component (C)) was not blended when the adhesive composition was prepared.

<Evaluation of peeling suppression performance of laminated body 1>
The peeling suppression performance during heating was evaluated for each of the laminates prepared in Example I-1 and Comparative Example I-1. Specifically, the laminate is folded in half to form a bent portion, and a clip is used as an evaluation sample, and the evaluation sample is heated at the heating temperature shown in Table 1 for 45 minutes to heat it. The condition of the bent portion of the later evaluation sample was observed with an optical microscope. The evaluation was performed according to the following criteria. The results are shown in Table 1.
A: No peeling is observed.
B: Slight voids are observed between the layers.
C: Peeling is observed between the layers.

As shown in Table 1, it was confirmed that in the laminate of Example I-1, sufficient peeling suppressing performance was exhibited even at the bent portion by using the predetermined adhesive composition. In the laminated body of Comparative Example I-1, it is presumed that the resin component of the electrostatic ink layer was melted and peeled off. Further, in Comparative Example I-1, it was confirmed that the tendency became remarkable as the heating temperature increased. On the other hand, it was confirmed that in the laminated body of Example I-1, sufficient peeling suppression performance was maintained even when it was hot. The laminate of Example I-1 is also expected to have a sufficient peeling suppressing effect even when the resin component is solidified when it is not heated (for example, at room temperature).

<Evaluation of peeling suppression performance of laminated body 2>
Each of the laminates prepared in Example I-1 and Comparative Example I-1 was heated in the same manner as in "Evaluation of peeling suppression performance of laminate No. 1" except that the heating temperature and heating time were changed. The time peeling suppression performance was evaluated. The results are shown in Table 2.

As shown in Table 2, even if the heating temperature and heating time were changed, the same tendency as in the above-mentioned "Evaluation of peeling suppression performance of laminated body 1" was confirmed. As the result of the laminate of Example I-1 shows, the container according to the present disclosure is sufficient for retort heat treatment at 120 ° C. or higher (for example, heat pressure sterilization treatment at 120 ° C. for 30 minutes). It was confirmed that it has a strong resistance.

<Heat seal test at bent part: Evaluation of peeling suppression performance Part 3>
Next, the effect of the seal with the bent portion provided was evaluated. A standing pouch (a container having the same configuration as the container shown in FIGS. 3 and 4) in which three laminates prepared in Example I-1 and Comparative Example I-1 are prepared and composed of the same three laminates is prepared. ) Was prepared. Specifically, the sheet to be the bottom sheet is folded in half and arranged between the two laminates to be the side sheets, and a pressure of 0.2 MPa is applied to the laminate using a thermal tilt tester. It was treated at the temperatures shown in Table 3 for 1 second and sealed. The laminate to be the bottom sheet portion of the standing pouch was arranged so that the sealant layer side was inside the container when folded in a mountain. As the thermal tilt tester, "HG-100" (product name) manufactured by Toyo Seiki Seisakusho Co., Ltd. was used. After preparation, the cross section including the bottom sheet portion of the standing pouch was observed with an optical microscope. As the evaluation criteria, the same criteria as in "Evaluation of peeling suppression performance of laminated body No. 1" were used. The results are shown in Table 3. Further, for reference, FIG. 9 shows the appearance of the bent portion of the laminated body as the bottom sheet of Example I-1 and Comparative Example I-1 before sealing and after sealing at 210 ° C.

As shown in Table 3, peeling is sufficiently suppressed in the laminate prepared in Example I-1 even in the heat treatment in a state where pressure is applied such that the sealant layers are bonded to each other. confirmed.

<Heat seal test at bent part: Evaluation of peeling suppression performance Part 4>
The pressure condition applied at the time of sealing or the time at the time of sealing was changed, and the same evaluation as the above-mentioned "Thermal sealing test at the bent portion: Evaluation of peeling suppression performance No. 3" was performed. The results are shown in Tables 4 and 5, and FIGS. 10 and 11.

As shown in Tables 4 and 5, and FIGS. 10 and 11, the laminate of Example I-1 is heat under the general sealing conditions for manufacturing a container by sealing the laminate. It was confirmed that the peeling was sufficiently suppressed even under the sealing conditions.

From the results of Example I-1 and Comparative Example I-1 described above, it was confirmed that the effect of suppressing peeling between the layers constituting the laminate was sufficiently exhibited by using the adhesive composition containing the epoxy compound. Was done. It is considered that the improvement of the strength of the electrostatic ink composition and the improvement of the adhesive strength between the layers contribute to the factors of the peeling suppressing effect. Hereinafter, for reference, an example in which the composition of the adhesive composition is adjusted is shown.

(Reference Example I-1)
[Preparation of laminate]
The laminate was prepared in the same manner as in Example I-1 except that the mass-based compounding ratio of each component in the adhesive composition was changed as shown in Table 5 in (A): (B): (C). Made. Further, the laminated strength of the obtained laminated body was measured by the method described later. The results are shown in Table 6.

<Evaluation of laminate strength of laminated body>
For the laminate prepared in Reference Example I-1, the laminate strength was measured according to the description of JIS K 6854-1: 1999. Specifically, first, the prepared laminate was cut into a width of 15 mm to prepare a measurement sample. After peeling the layers at the edges of the measurement sample, the peel strength between the layers of the laminate was measured using a tensile tester under the conditions of an angle of 90 °, a tensile speed of 300 mm / min, and room temperature. This peeling strength was defined as the laminating strength at room temperature (20 ° C.). The measurement results are as shown in Table 6.

(Reference Example I-2)
The first liquid consisting of an aliphatic polyester polyol (A) (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takelac A626), polyisocyanate (B) (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takenate A50) and an epoxy compound (C). ), And a two-component adhesive separately contained in a container were prepared. The first liquid and the second liquid were mixed to prepare an adhesive composition having the formulation shown in Table 6. A laminate was prepared in the same manner as in Reference Example I-1 except that this adhesive composition was used, and the adhesive strength was measured. The measurement results are as shown in Table 6.

(Comparative Example I-2)
A laminate was prepared in the same manner as in Reference Example I-1 except that the epoxy compound (C) was not blended when the adhesive composition was prepared, and the adhesive strength was measured. The measurement results are as shown in Table 6.

(Comparative Example I-3)
The epoxy compound of the formula (1) was applied to the printed surface on which the electrostatic ink composition was printed to provide an epoxy coating layer, and the adhesive composition of Comparative Example I-2 was applied to the epoxy coating layer. A laminate was prepared in the same manner as in Reference Example I-1 except for the above, and the adhesive strength was measured. The coating amount of the epoxy coating layer was set to an amount corresponding to 0.53 parts by mass in the formulation shown in Table 5. The measurement results are as shown in 6.

In the column of [(B) / (A)] × 100 in Table 6, the blending amount (parts by mass) of polyisocyanate with respect to 100 parts by mass of the aliphatic polyester polyol is shown. In the column of [(C) / (A)] × 100 in Table 6, the blending amount (parts by mass) of the epoxy compound with respect to 100 parts by mass of the aliphatic polyester polyol is shown. The column of "epoxide group / isocyanate group" in Table 6 shows the molar ratio of the epoxy group contained in the epoxy compound (C) to the isocyanate group contained in the polyisocyanate (B).

As shown in Table 6, the laminates of Reference Examples I-1 to I-2 in which the adhesive layer containing the epoxy compound and the printed surface are adhered are compared by adhering the adhesive layer containing no epoxy compound and the printed surface. It was confirmed that the adhesive strength was higher than that of the laminate of Example I-2. In Comparative Example I-3, a relatively high adhesive strength was obtained, but the number of steps increased because the epoxy coating layer was formed in addition to the adhesive layer. Curing (aging) of the epoxy coating layer took two days, and the productivity decreased.

In the laminated body of Comparative Example I-2, it was separated near the interface between the electrostatic ink layer and the primer layer. In the laminated body of Comparative Example I-3, the electrostatic ink layer was coagulated and broken. On the other hand, the laminates of Reference Examples I-1 to I-2 exhibit sufficient lamination strength, and when a load is intentionally applied, they are separated at the interface between the electrostatic ink layer and the adhesive layer. , No cohesive failure of the electrostatic ink layer was observed. This suggests that the cohesive force of the electrostatic ink layer is improved. In Reference Examples I-1 to I-2, the molar ratio of the isocyanate group contained in the polyisocyanate (B) to the hydroxyl group of the aliphatic polyester polyol (A) was in the range of 0.5 to 10.

Next, in addition to the laminate strength, the hot water laminate strength and the seal strength were measured for the laminates of Reference Example I-1 and Comparative Example I-3. For the measurement, those having a total ink coverage of 500% and those having a total ink coverage of 200% were used. The details of the measurement procedure are as follows.

[Measurement of hot water laminate strength]
The laminates of Reference Example I-1 and Comparative Example I-3 were cut to a width of 15 mm to obtain measurement samples. After peeling off the layers at the end of the measurement sample, the peeling strength was measured using a tensile tester in a state of being immersed in hot water at 90 ° C. That is, the peeling angle was free, and the tensile speed was 300 mm / min. This peeling strength is shown in Table 7 as the hot water laminate strength.

[Measurement of seal strength (before heat treatment)]
Using the pair of laminates of Reference Example I-1, heat sealing was performed so that the unstretched polypropylene films overlap each other to form a sealed portion. As a result, the unstretched polypropylene films were heat-welded to each other to prepare a measurement sample having a width of 15 mm. In accordance with JIS K 7127: 1999, the seal strength at the seal portion of the prepared measurement sample was measured. For the measurement, the peel strength between the heat seals was measured using a tensile tester under the conditions of a peeling angle: 90 °, a tensile speed: 300 mm / min, and a normal temperature (20 ° C). This peeling strength was defined as the sealing strength "before heat treatment". The measurement results are as shown in Table 7. A similar measurement sample was prepared using the laminate of Comparative Example I-3, and the same measurement was performed. The measurement results are as shown in Table 7.

[Measurement of seal strength (after boiling)]
The measurement sample prepared in the above-mentioned "Measurement of seal strength (before heat treatment)" was heated in water at 100 ° C. for 30 minutes. After that, the seal strength was measured by the same procedure as the above-mentioned "Measurement of seal strength (before heat treatment)". The measurement results are as shown in the column of "after boiling" in Table 7.

[Measurement of seal strength after retort (120 ° C)]
The retort heat treatment (120 ° C. × 30 minutes) of the measurement sample prepared in the above-mentioned “Measurement of seal strength (before heat treatment)” was performed. Using a tensile tester, the peel strength was measured in the same manner as in "Measurement of seal strength (before heat treatment)". The measurement results are as shown in the column of "120 ° C. x 30 minutes" in Table 7.

[Measurement of seal strength after retort (130 ° C)]
The retort heat treatment (130 ° C. × 30 minutes) of the measurement sample prepared in the above-mentioned “Measurement of seal strength (before heat treatment)” was performed. Using a tensile tester, the peel strength was measured in the same manner as in "Measurement of seal strength (without heat treatment)". The measurement results are as shown in the column of "130 ° C. x 30 minutes" in Table 7.

As shown in Table 7, the hot water laminate strength of Reference Example I-1 was significantly higher than that of Comparative Example I-3. It was also confirmed that the seal strength of Reference Example I-1 was superior to that of Comparative Example I-3. In particular, the seal strength of Reference Example I-1 was sufficiently high even after boiling, whereas the seal strength of Comparative Example I-3 was significantly reduced after boiling. It was confirmed that the laminate strength and the seal strength of the laminate of Comparative Example I-3 were significantly reduced when heated in the presence of moisture.

(Example II-1)
[Preparation of laminate]
A nylon film (thickness: 15 μm) was prepared as a base material. A water-based primer resin (resin containing polyethyleneimine, manufactured by Michelman, trade name: DP050) was applied to one main surface of this nylon film to form a primer layer. Aqueous polyethyleneimine was applied so that the amount applied was 0.10 to 0.18 g / m ² .

Predetermined printing was performed on the surface of the primer layer using a digital printing machine (manufactured by HP, Digital printing machine for Indigo 20000 label and packaging). As the electrostatic ink composition, an electrostatic ink composition (HP Indigo electro ink) containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid was used. As the colors of the electrostatic ink composition, white (W) and cyan (C) were used as shown in Table 8. A plurality of samples having different colors and ink coverage of the electrostatic ink composition were prepared. The ink coverage was as shown in Table 8. Each ink coverage was adjusted according to the settings of the digital printing machine. As shown in Table 8, the total ink coverage was 100 to 300%.

An LLDPE film (manufactured by Futamura Chemical Co., Ltd., trade name: XMTN, thickness: 60 μm) was prepared, and the adhesive layer on the substrate and the LLDPE film were laminated to obtain a laminate using the above dry laminating apparatus. .. The curing time (aging) was set at 40 ° C. for 2 days.

(Examples II-2 and II-3)
A laminate was prepared in the same manner as in Example II-1 except that the color and ink coverage of the electrostatic ink composition were changed as shown in Table 8.

(Comparative Examples II-1 to II-3)
Laminates were prepared in the same manner as in Examples II-1 to II-3, except that the epoxy compound (component (C)) was not blended when the adhesive composition was prepared.

[Creation of packaging]
Two 150 mm × 200 mm rectangular laminates were prepared for each of Examples II-1 to II-3 and Comparative Examples II-1 to II-3. At this time, the laminates of Examples II-1 and Comparative Example II-1 were prepared so that the electrostatic ink composition was not applied to the outer peripheral portion having a width of 10 mm, and Examples II-2 to II- As the laminates of No. 3 and Comparative Examples II-2 to II-3, those in which the antistatic ink composition was also applied to the outer peripheral portion were prepared. By stacking two laminates with their main surfaces on the LLDPE film side facing each other and using heat sealing, a pair of ends along the longitudinal direction and one end along the lateral direction are bonded together. Seals were formed on three of the four sides around the laminate. FIG. 12 shows the main surface of the laminated body 310. First, the sealing portions 111 were formed on the three sides of the laminated body 310 by the first heat sealing, and a packaging bag in a state where the three sides were closed was created. At this time, the width T (see FIG. 12) of the seal portion 111 was set to 10 mm. A seal portion 114 was formed by laminating two laminated bodies by heat sealing even on one side on which the seal portion 111 was not formed. The width T of the seal portion 114 is also set to 10 mm. That is, when the laminates of Example II-1 and Comparative Example II-1 are used, the packaging bag in which the electrostatic ink composition is not printed in the laminates at the

seal portions

111 and 114. Prepared.

Before the sealing portion 114 was completely sealed to bring the inside into a sealed state, 500 ml of water was introduced as the contents in the packaging bag. As a result, the packages according to Examples II-1 to II-3 and Comparative Examples II-1 to II-3 were prepared. As described above, the inside of the package was filled with 500 ml of water.

<Evaluation of laminate strength (before boiling)>
For each of the packages according to Examples II-1 to II-3 and Comparative Examples II-1 to II-3, the laminate strength was measured according to the description of JIS K 6854-1: 1999. Specifically, Examples II-1 to II-3 before filling with water instead of the packages according to Examples II-1 to II-3 and Comparative Examples II-1 to II-3 prepared first. And the laminate according to Comparative Examples II-1 to II-3 was cut into a width of 15 mm to prepare a measurement sample. After peeling the layers at the edges of the measurement sample, the peel strength between the layers of the laminate was measured using a tensile tester under the conditions of an angle of 90 °, a tensile speed of 300 mm / min, and room temperature. This peeling strength was defined as the laminating strength at room temperature (20 ° C.). The measurement results are as shown in Table 8.

<Evaluation of laminate strength (after boiling)>
Each of the packages according to Examples II-1 to II-3 and Comparative Examples II-1 to II-3 was heated in water at 90 ° C. for 30 minutes (boil heat treatment). Then, a part of the package was cut out by the same procedure as the above-mentioned <Evaluation of laminate strength (before boiling)>, and the laminate strength was measured. The measurement results are as shown in Table 8.

From the above results, it was confirmed that the presence of the electrostatic ink layer reduces the lamination strength as compared with the case where the electrostatic ink layer does not exist (Example II-1 and Comparative Example II-1). It was also confirmed that the laminate strength decreases as the ink coverage increases. In particular, when the ink coverage becomes 300%, in Comparative Example II-3, the laminate strength of the package (laminate) is 2 or less both before and after boiling, and the packaging bag for heat treatment is used. It was confirmed that it may not be able to withstand the use as. In all of Examples II-1 to II-3 and Comparative Examples II-1 to II-3, the laminate strength is increased after boiling. It is presumed that this is because the reaction of isocyanate as a curing agent contained in the adhesive composition proceeded when boiling was performed.

<Evaluation of seal strength (before boiling)>
Before filling each of the packages according to Examples II-1 to II-3 and Comparative Examples II-1 to II-3 with water (before the sealing portion 114 is completely sealed to keep the inside sealed). ), A measurement sample having a width of 15 mm was prepared. In accordance with JIS K 7127: 1999, the seal strength at the seal portion of the prepared measurement sample was measured. In the measurement, the peeling strength between the heat seals was measured using a tensile tester under the conditions of a peeling angle of 90 °, a tensile speed of 300 mm / min, and a normal temperature (20 ° C.). This peeling strength was defined as the sealing strength "before heat treatment". The measurement results are as shown in Table 9.

<Evaluation of seal strength (after boiling)>
Each of the packages according to Examples II-1 to II-3 and Comparative Examples II-1 to II-3 was heated in water at 90 ° C. for 30 minutes (boil heat treatment). Then, the package was opened, the water filled inside was removed, and after A, the seal strength was measured by the same procedure as the above-mentioned "evaluation of seal strength (before boiling)". The measurement results are as shown in Table 9.

Note that "film breakage" in Table 9 indicates that the measurement was completed with the film broken. Further, "triangular peeling" refers to a state in which peeling occurs between layers at least on one side of the pair of laminated bodies. Further, "edge breakage" indicates a state in which damage occurs at the boundary portion between the heat-sealed portion and the inside of the bag.

From the above results, it was confirmed that the seal strength was lowered due to the presence of the electrostatic ink layer as compared with the case where the electrostatic ink layer was not present (Example II-1 and Comparative Example II-1). It was also confirmed that the seal strength decreases as the ink coverage increases. As for Comparative Examples II-2 and II-3, since the sealing strength at least one before and after boiling is 40 N / 15 mm or less, it cannot withstand the use as a packaging bag for heat treatment. It was confirmed that there was sex.

<Aerobic boil test>
For each of Examples II-1 to II-3 and Comparative Examples II-1 to II-3, two 150 mm × 200 mm rectangular laminates were prepared, and the same method as for preparing the package described above was used. , A package for aeration boil test was prepared.

Before the sealing portion 114 is completely sealed to bring the inside into a sealed state, 300 ml of water is introduced as the content in the packaging bag, and then 100 ml of air is further filled to determine the lamination strength and the point. Different from the packaging for seal strength. As a result, packages for the aeration boil test according to Examples II-1 to II-3 and Comparative Examples II-1 to II-3 were prepared. As described above, the inside of the package was filled with 300 ml of water and 100 ml of air.

Three packages of Examples II-1 to II-3 and Comparative Examples II-1 to II-3 were prepared, and each of them was heated in water at 100 ° C. for 60 minutes. The surface of the package after heating was visually observed, and the presence or absence of floating of the printed surface due to the electrostatic ink composition on the surface of the laminate was observed. The measurement results are as shown in Table 10.

From the results of the above Examples and Comparative Examples, it was confirmed that the adhesive composition containing the polyol, polyisocyanate and epoxy compound has resistance to heat treatment. It is considered that the improvement of the strength of the electrostatic ink composition and the improvement of the adhesive strength between the layers contribute to the improvement of the resistance to such heat treatment. The following experiments were conducted to verify these improving effects.

(Reference Example II-1)
[Preparation of adhesive composition and laminate]
A polyethylene terephthalate film (PET film, thickness: 12 μm) was prepared as a base material. The same aqueous primer resin as in Example II-1 was applied to one surface of this PET film to form a primer layer. The amount of aqueous polyethyleneimine applied was also the same as in Example II-1.

Using the digital printing machine used in Example II-1, predetermined printing was performed on the surface of the primer layer. As the electrostatic ink composition, an electrostatic ink composition (HP Indigo electro ink) containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid was used. As the colors of the electrostatic ink composition, white (W), yellow (Y), magenta (M), and cyan (C) were used as shown in Table 11. A plurality of samples having different colors and ink coverage of the electrostatic ink composition were prepared. The ink coverage of each color and the total thereof are as shown in Table 11. As shown in Table 11, the total ink coverage was 200 to 500%.

The same adhesive composition as in Example II-1 was prepared, and the adhesive composition was applied to the printed surface in the same procedure as in Example II-1 to form an adhesive layer. The coating amount of the adhesive composition was 4.0 g / m ² .

A laminated film having an aluminum foil (manufactured by Toyo Aluminum K.K., thickness: 7 μm), a nylon film, and a non-stretched polypropylene film in this order was prepared. Using the same dry laminating apparatus as in Example II-1, the adhesive layer on the base material and the aluminum foil of the laminated film were made to face each other, and the aluminum foil and the adhesive layer were laminated to obtain a laminated body. The curing time (aging) was set at 40 ° C. for 2 days.

[Measurement of adhesive strength (normal temperature)]
The adhesive strength of the produced laminate was measured according to JIS K 6854-1: 1999. Specifically, the prepared laminate was cut into a width of 15 mm to prepare a measurement sample. After peeling the layers at the edges of the measurement sample, the peel strength between the layers of the laminate was measured using a tensile tester under the conditions of an angle of 90 °, a tensile speed of 300 mm / min, and room temperature. This peeling strength was defined as the adhesive strength at room temperature (20 ° C.). The measurement results are as shown in Table 11.

(Reference Examples II-2 to II-6)
A laminate was prepared in the same manner as in Reference Example II-1 except that the composition of the adhesive composition was changed as shown in Tables 11 and 12, and the adhesive strength was measured. The measurement results are as shown in Tables 11 and 12.

(Reference Example II-7)
The first liquid consisting of an aliphatic polyester polyol (A) (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takelac A626), polyisocyanate (B) (manufactured by Mitsui Chemicals Co., Ltd., trade name: Takenate A50) and an epoxy compound (C). ), And a two-component adhesive separately contained in a container were prepared. The first liquid and the second liquid were mixed to prepare an adhesive composition having the formulation shown in Table 12. A laminate was prepared in the same manner as in Reference Example II-1 except that this adhesive composition was used, and the adhesive strength was measured. The measurement results are as shown in Table 12.

(Comparative Example II-4)
A laminate was prepared in the same manner as in Reference Example II-1 except that the epoxy compound (C) was not blended when the adhesive composition was prepared, and the adhesive strength was measured. The measurement results are as shown in Table 12.

(Comparative Example II-5)
The epoxy compound of the formula (1) was applied to the printed surface on which the electrostatic ink composition was printed to provide an epoxy coating layer, and the adhesive composition of Comparative Example II-4 was applied to the epoxy coating layer. A laminate was prepared in the same manner as in Reference Example II-1 except for the above, and the adhesive strength was measured. The coating amount of the epoxy coating layer was set to an amount corresponding to 0.53 parts by mass in the formulation shown in Table 11. The measurement results are as shown in Table 12.

In the column of [(B) / (A)] × 100 in Tables 11 and 12, the blending amount (parts by mass) of polyisocyanate with respect to 100 parts by mass of the aliphatic polyester polyol is shown. In the column of [(C) / (A)] × 100 in Tables 11 and 12, the blending amount (parts by mass) of the epoxy compound with respect to 100 parts by mass of the aliphatic polyester polyol is shown. The columns of "epoxy group / isocyanate group" in Tables 11 and 12 show the molar ratio of the epoxy group contained in the epoxy compound (C) to the isocyanate group contained in the polyisocyanate (B).

As shown in Tables 11 and 12, the laminate of Reference Examples II-1 to II-7 in which the adhesive layer containing the epoxy compound and the printed surface are bonded has the adhesive layer containing no epoxy compound and the printed surface. It was confirmed that the adhesive strength was higher than that of the adhered laminate of Comparative Example II-4. In Comparative Example II-5, a relatively high adhesive strength was obtained, but the number of steps increased because an epoxy coating layer was formed in addition to the adhesive layer. Curing (aging) of the epoxy coating layer took two days, and the productivity decreased.

In the laminated body of Comparative Example II-4, the layers were separated near the interface between the electrostatic ink layer and the primer layer. In the laminated body of Comparative Example II-5, the electrostatic ink layer was coagulated and broken. On the other hand, in the laminates of Reference Examples II-1 to II-7, they were separated at the interface between the electrostatic ink layer and the adhesive layer, and no cohesive failure of the electrostatic ink layer was observed. This suggests that the cohesive force of the electrostatic ink layer is improved. In Reference Examples II-1 to II-7, the molar ratio of the isocyanate group contained in the polyisocyanate (B) to the hydroxyl group of the aliphatic polyester polyol (A) was in the range of 0.5 to 10.

Next, the adhesive strength, hot water adhesive strength, and seal strength of the laminates of Reference Example II-5 and Comparative Example II-5 were measured. For the measurement, those having a total ink coverage of 500% and those having a total ink coverage of 200% were used. The details of the measurement procedure are as follows.

[Measurement of hot water adhesion strength]
The laminates of Reference Example II-5 and Comparative Example II-5 were cut to a width of 15 mm to obtain measurement samples. After peeling off the layers at the end of the measurement sample, the peeling strength was measured using a tensile tester in a state of being immersed in hot water at 90 ° C. That is, the peeling angle was set to free, and the tensile speed was set to 300 mm / min. This peeling strength is shown in Table 13 as the hot water adhesion strength.

[Measurement of seal strength (before heat treatment)]
Using the pair of laminates of Reference Example II-5, heat sealing was performed so that the unstretched polypropylene films overlap each other to form a sealed portion. As a result, the unstretched polypropylene films were heat-welded to each other to prepare a measurement sample having a width of 15 mm. In accordance with JIS K 7127: 1999, the seal strength at the seal portion of the prepared measurement sample was measured. In the measurement, the peeling strength between the heat seals was measured using a tensile tester under the conditions of a peeling angle of 90 °, a tensile speed of 300 mm / min, and a normal temperature (20 ° C.). This peeling strength was defined as the sealing strength "before heat treatment". The measurement results are as shown in Table 13. A similar measurement sample was prepared using the laminate of Comparative Example II-5, and the same measurement was performed. The measurement results are as shown in Table 13.

[Measurement of seal strength (after boiling)]
The measurement sample prepared in the above-mentioned "Measurement of seal strength (before heat treatment)" was heated in water at 100 ° C. for 30 minutes. After that, the seal strength was measured by the same procedure as the above-mentioned "Measurement of seal strength (without heat treatment)". The measurement results are as shown in the column of "after boiling" in Table 13.

[Measurement of seal strength after retort (120 ° C)]
The retort heat treatment (120 ° C. × 30 minutes) of the measurement sample prepared in the above-mentioned “Measurement of seal strength (before heat treatment)” was performed. Using a tensile tester, the peel strength was measured in the same manner as in "Measurement of seal strength (before heat treatment)". The measurement results are as shown in the column of "120 ° C. x 30 minutes" in Table 13.

[Measurement of seal strength after retort (130 ° C)]
The retort heat treatment (130 ° C. × 30 minutes) of the measurement sample prepared in the above-mentioned “Measurement of seal strength (before heat treatment)” was performed. Using a tensile tester, the peel strength was measured in the same manner as in "Measurement of seal strength (without heat treatment)". The measurement results are as shown in the column of "130 ° C. x 30 minutes" in Table 13.

As shown in Table 13, the hot-water adhesive strength of Reference Example II-5 was significantly higher than that of Comparative Example II-5. It was also confirmed that the seal strength of Reference Example II-5 was superior to that of Comparative Example II-5. In particular, the seal strength of Reference Example II-5 was sufficiently high even after boiling, whereas the seal strength of Comparative Example II-5 was significantly reduced after boiling. It was confirmed that the adhesive strength and the sealing strength of the laminated body of Comparative Example II-5 were significantly reduced when heated in the presence of moisture.

(Reference Example II-8)
[Preparation of adhesive composition and laminate]
A polyethylene terephthalate film (PET film, thickness: 12 μm) was prepared as a base material. The same aqueous primer resin as in Example II-1 was applied to one surface of this PET film to form a primer layer. The amount of aqueous polyethyleneimine applied was also the same as in Example II-1.

Using the digital printing machine used in Example II-1, predetermined printing was performed on the surface of the primer layer. As the colors of the electrostatic ink composition, white (W), yellow (Y), magenta (M), and cyan (C) were used. As the ink coverage, W200% and C100% + M100% + Y100% + W200% were prepared. In Table 14, the former was designated as “ink coverage (1)” and the latter was designated as “ink coverage (2)”. In this way, two types of samples having different ink coverage of the electrostatic ink composition were prepared.

An adhesive composition was prepared with Example II-1, and the adhesive composition was applied to the printed surface in the same procedure as in Example II-1 to form an adhesive layer. The coating amount of the adhesive composition was 4.0 g / m ² .

The laminated film (laminated film obtained by laminating a nylon film and a non-stretched polypropylene film with a commercially available adhesive) used in Example II-1 is used as an adhesive for a base material in the same manner as in Example II-1. It was bonded to a layer to obtain a laminate. The curing time (aging) was 40 ° C. × 2 days.

The seal strength (before heat treatment) and the seal strength (after boiling) of the laminate thus obtained were measured. The measurement results are as shown in Table 14. Further, the adhesive strength (before heat treatment) and the hot adhesive strength (120 ° C.) were measured by the following procedure.

Using a pair of laminates of Reference Example II-8, heat-sealing was performed so that the unstretched polypropylene films overlap each other, and a three-sided bag having a sealing portion was produced. Water was sealed in this three-sided bag. Then, a retort heat treatment (120 ° C. × 30 minutes) was carried out using a retort processing device (manufactured by Hisaka Works). After the retort heat treatment, it was cut to a width of 15 mm, a sample of the seal portion was taken, and the interlayer strength between the electrostatic ink layer and the layer in contact with the electrostatic ink layer was measured. The measured peel strength is shown in the column of "Hot adhesive strength (120 ° C.)" in Table 14. Table 14 also shows the adhesive strength before the retort heat treatment.

(Reference Examples II-9 to II-12)
When the adhesive composition was prepared, a laminate was prepared in the same manner as in Reference Example II-8, except that the blending amount of polyisocyanate (B) was changed as shown in Table 14. The prepared laminate was evaluated in the same manner as in Reference Example II-8. The evaluation results are as shown in Table 14.

(Comparative Example II-6)
A laminate was produced in the same manner as in Comparative Example II-4, except that the printed surface on which the electrostatic ink composition was printed was laminated with a handler laminator machine without using a dry laminating apparatus. The colors and ink coverage of the electrostatic ink composition were as shown in Table 14. The prepared laminate was evaluated in the same manner as in Reference Example II-8. The evaluation results are as shown in Table 14.

As shown in Table 14, it was confirmed that in each reference example, high adhesive strength and seal strength can be obtained even under heating conditions. Further, it was confirmed that the hot adhesive strength (120 ° C.) and the sealing strength (before heat treatment and after boiling) can be sufficiently increased by adjusting the mixing ratio of the polyisocyanate (B) to the aliphatic polyester polyol (A). Was done. On the other hand, in Comparative Example II-6 in which the epoxy compound (C) was not used, it was confirmed that the adhesive strength and the seal strength were significantly reduced when exposed to high temperature hot water treatment conditions. In Reference Examples II-8 to II-12, the molar ratio of the isocyanate group contained in the polyisocyanate (B) to the hydroxyl group contained in the aliphatic polyester polyol (A) was in the range of 0.5 to 10. rice field.

(Reference Examples II-13 to II-17)
Aliphatic polyester polyol (A1) (Mitsui Chemicals, Inc., Takelac A525), polyisocyanate (B1) (Mitsui Chemicals, Inc., Takenate A52), and 3', 4'-epoxycyclohexylmethyl as the epoxy compound (C). An adhesive composition was prepared by blending −3,4 epoxycyclohexanecarboxylate. The blending ratio was as shown in Table 15. Laminates were prepared and evaluated in the same manner as in Reference Examples II-8 to II-12, except that such an adhesive composition was used. The evaluation results are as shown in Table 15.

(Comparative Example II-7)
An aliphatic polyester polyol (A1) (Mitsui Chemicals, Inc., Takelac A525) and a polyisocyanate (B1) (Mitsui Chemicals, Inc., Takenate A52) were blended as polyols to prepare an adhesive composition. The blending ratio was as shown in Table 15. A laminate was prepared and evaluated in the same manner as in Comparative Example II-4 except that such an adhesive composition was used. The evaluation results are as shown in Table 15.

As shown in Table 15, it was confirmed that even when the combination of the aliphatic polyester polyol and the polyisocyanate was changed, high adhesive strength and seal strength could be obtained in each reference example. Further, it was confirmed that the hot adhesive strength (120 ° C.) and the sealing strength (without heat treatment and after boiling) can be sufficiently increased by adjusting the blending ratio of the polyisocyanate (B1) with the aliphatic polyester polyol (A1). Was done. On the other hand, in Comparative Example II-7 in which the epoxy compound (C) was not used, it was confirmed that the adhesive strength and the seal strength were significantly reduced when exposed to high temperature hot water treatment conditions. In Reference Examples II-13 to II-17, the molar ratio of the isocyanate group contained in the polyisocyanate (B1) to the hydroxyl group contained in the aliphatic polyester polyol (A1) was in the range of 0.5 to 10. rice field.

According to the present disclosure, it is possible to provide a packaging bag having an electrostatic ink layer produced by a digital printing machine and having sufficient resistance to heat treatment.

10 ... base material, 20 ... sealant layer, 30 ... adhesive layer, 40 ... primer layer, 50, 51 ... electrostatic ink layer, 52 ... printing part, 60 ... bent part, 70 ... spout, 72 ... spout, 74 ... Flange, 100, 110 ... Container, 101, 103, 111, 114, 121, 122 ... Seal part, 102, 112, 124, 132 ... Storage part, 120, 130 ... Packaging bag, 140 ... Opening means, 141 ... Half-cut wire, 144 ... Easy-opening processed part, 200 ... Body part, 300, 302, 304, 306, 310 ... Laminated body, 400 ... Packaging body.

Claims

A container having a body portion having a bent portion.
The body portion is composed of at least one laminated body.
The laminate includes a base material, a primer layer, an adhesive layer, and a sealant layer in this order, and a printing portion in which at least a part of the main surface of the primer layer on the sealant layer side is composed of an electrostatic ink composition. Have,
The adhesive layer is a container containing at least one of an adhesive composition containing an epoxy compound and a cured product thereof.
The container according to claim 1, which has the printing portion on the bent portion.
The container according to claim 1 or 2, wherein the epoxy compound contains a bifunctional alicyclic epoxy compound.
The adhesive composition further comprises a polyol and contains
The container according to any one of claims 1 to 3, wherein the polyol contains an aliphatic polyester polyol, and the epoxy compound has an epoxy group at both ends.
The adhesive composition further comprises polyisocyanate and
The container according to claim 4, wherein the polyisocyanate contains a xylylene diisocyanate derivative.
The container according to any one of claims 1 to 5, further comprising a spout that connects to the body portion.
The container according to claim 6, wherein the spout has a tubular spout and a flange extending outward from the peripheral edge of the lower end of the spout.
The container according to any one of claims 1 to 7, wherein the body portion is composed of one of the laminated bodies.
The container according to any one of claims 1 to 8, which is composed of two laminated bodies whose body is a side sheet and one laminated body whose bottom sheet is a bottom sheet.
A packaging bag for heat treatment, which is composed of a laminate having a base material, a primer layer, an electrostatic ink layer, an adhesive layer, and a sealant layer in this order.
The adhesive layer is a packaging bag for heating, which contains at least one of an adhesive composition containing an epoxy compound and a cured product thereof.
The packaging bag for heating according to claim 10, wherein the primer layer contains a polyethyleneimine resin.
The outer peripheral portion includes a sealing portion for adhering the sealant layers of the two laminated bodies to each other.
The packaging bag for heating according to claim 10 or 11, wherein the sealing portion has an ink coverage of 300% or less in the electrostatic ink layer.
The heating packaging bag according to any one of claims 10 to 12, wherein the epoxy compound contains a bifunctional alicyclic epoxy compound.
The adhesive composition further comprises a polyol and contains
The packaging bag for heating according to any one of claims 10 to 13, wherein the polyol contains an aliphatic polyester polyol, and the epoxy compound includes one having an epoxy group at both ends.
The adhesive composition further comprises polyisocyanate and
The packaging bag for heating according to claim 14, wherein the polyisocyanate contains a xylylene diisocyanate derivative.