Spouted pouch and manufacturing method thereof, laminate, packaging material and packaging body

Abstract

To provide a laminate excellent in heat resistance, while having an electrostatic ink layer formed of an electrostatic ink composition.SOLUTION: A laminate 300 for a pouch with a spout, comprises, in the following order, a substrate film 10, an adhesive layer 30 and a sealant layer 20 welded to the spout, and further comprises an electrostatic ink layer 50 adhered to the adhesive layer 30. The adhesive layer 30 is formed from at least one of an adhesive composition containing polyol, polyisocyanate and an epoxy compound, and a cured product thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a spouted pouch and a method for manufacturing the same, as well as a laminate, a packaging material, and a packaging body. [Background technology]

[0002] Packages made of thin films or sheets are used as packaging bags for sealing and preserving packaged items such as beverages and food products. Various information such as the product, brand, and manufacturer is printed on such packaging bags. Digital printers using electrostatic ink compositions are known as a means for such printing.

[0003] For example, Patent Document 1 proposes applying a primer resin to a first flexible substrate such as a PET film to obtain a coated surface, performing electrostatic printing on the coated surface using a digital printer (HP's Indigo 20000 label and packaging digital printer), and then applying a crosslinking composition. After performing the predetermined steps in this manner, the proposed technology involves laminating the first flexible substrate coated with the predetermined components and a second flexible substrate to obtain a packaging material.

[0004] Meanwhile, spout-equipped pouches are known as packaging containers for hermetically storing packaged items such as beverages and fluid food products. The spout in a spout-equipped pouch is attached to the pouch body by heat welding with the sealant layer of the pouch body. Patent Document 2 proposes using a spout made of an integrally molded resin body containing an olefin-based resin and an ethylene-vinyl alcohol copolymer, and a sealant layer made of an olefin-based resin film, in order to achieve good heat welding between the spout in a spout-equipped pouch and the sealant layer of the pouch body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-530478 [Patent Document 2] International Publication No. 2018 / 062126 Summary of the Invention [Problem to be solved by the invention]

[0006] In a spout-equipped pouch such as that shown in Patent Document 2, the spout and the sealant layer of the pouch body are welded together while being pressed under high-temperature conditions, which is required to ensure a sufficiently strong bond between the spout and the sealant layer. Digital printing using an electrostatic ink composition allows for small-lot production, and therefore digitally printed laminates are used for various packaging materials. However, because the electrostatic ink layer made of an electrostatic ink composition does not have sufficient heat resistance, digital printing on the pouch body of a spout-equipped pouch can sometimes result in discoloration of the welded portion between the spout and the pouch body.

[0007] Therefore, the present disclosure provides a laminate that has excellent heat resistance while having an electrostatic ink layer made of an electrostatic ink composition. It also provides a spout-equipped pouch that has an electrostatic ink layer made of an electrostatic ink composition and is capable of sufficiently suppressing discoloration of the welded portion with the spout, a method for manufacturing the same, and a package. It also provides a packaging material that is suitable for use as the pouch body of such a spout-equipped pouch. [Means for solving the problem]

[0008] A laminate according to one aspect of the present disclosure is a laminate for a pouch with a spout, comprising, in this order, a base film, an adhesive layer, and a sealant layer welded to the spout, and an electrostatic ink layer adhered to the adhesive layer, wherein the adhesive layer is composed of at least one of an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, and a cured product thereof.

[0009] Electrostatic ink compositions used in digital printing tend to have poorer heat resistance than other inks. Therefore, when a spout-equipped pouch is manufactured using a laminate including an electrostatic ink layer composed of the electrostatic ink composition, welding the spout to the pouch body causes the electrostatic ink layer to flow, resulting in discoloration at the welded portion. In contrast, in the laminate disclosed herein, the adhesive layer that adheres to the electrostatic ink layer is composed of at least one of an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, and a cured product thereof. Such an adhesive layer is believed to have the effect of sufficiently coagulating the electrostatic ink composition that constitutes the electrostatic ink layer and improving adhesive strength. This effect is believed to occur when the epoxy compound penetrates from the adhesive layer into the electrostatic ink layer, resulting in crosslinking between the epoxy compound and the electrostatic ink composition. Therefore, the laminate has excellent heat resistance despite having an electrostatic ink layer composed of the electrostatic ink composition. Even when such a laminate is used as a laminate (laminated film) for a spout-equipped pouch to which a spout is welded, discoloration at the welded portion can be sufficiently suppressed.

[0010] The laminate may have a primer layer between the substrate film and the electrostatic ink layer, which can further improve the adhesion of the electrostatic ink layer.

[0011] The polyol in the adhesive layer may include an aliphatic polyester polyol, and the epoxy compound may include one having epoxy groups at both ends. Such an adhesive layer has high adhesive strength even in high-temperature environments. Therefore, when welding the spout, it is possible to sufficiently prevent gaps from forming at the interface between the electrostatic ink layer and the adhesive layer and to prevent the electrostatic ink layer from flowing. This further reduces discoloration caused by welding.

[0012] The epoxy compound in the adhesive layer may include a bifunctional alicyclic epoxy compound. The bifunctionality of such an epoxy compound increases the number of crosslinking points with the electrostatic ink composition that constitutes the electrostatic ink layer, further strengthening the adhesion between the adhesive layer and the electrostatic ink layer. Furthermore, the alicyclic nature of the epoxy compound can suppress reaction with polyisocyanate due to steric hindrance. This allows for stable curing, resulting in excellent adhesion at the interface between the electrostatic ink layer and the adhesive layer.

[0013] The polyisocyanate may contain a xylylene diisocyanate derivative. Such polyisocyanate has excellent reactivity with polyol. This improves the curing properties of the adhesive layer and further suppresses discoloration of the spouted pouch.

[0014] A packaging material according to one aspect of the present disclosure is a packaging material for a pouch with a spout, comprising a sealed portion formed by heat-sealing the sealant layers of any of the laminates described above, and a non-sealed portion in which the sealant layers face each other and a spout is welded.

[0015] This packaging material comprises a sealed portion formed by heat-sealing the sealant films of any of the above-mentioned laminates together, and a non-sealed portion to which a spout is welded. Because the above-mentioned laminate has excellent heat resistance, discoloration in the sealed portion is suppressed, and discoloration in the non-sealed portion to which the spout is welded can also be suppressed. Therefore, the laminate can be suitably used as a packaging material for spout-equipped pouches.

[0016] A spout-equipped pouch according to one aspect of the present disclosure comprises a pouch body having a seal portion formed by heat-sealing the sealant layers of any of the above-described laminates and having a storage portion for accommodating a packaged item, and a spout welded to the sealant layer of the laminate in the pouch body. Because the above-described laminate has excellent heat resistance, the spout-equipped pouch can sufficiently suppress discoloration of the pouch body at the welded portion with the spout. Such a spout-equipped pouch can fully demonstrate the performance of high-precision digital printing.

[0017] A package according to one aspect of the present disclosure includes a spouted pouch and a packaged item contained therein. Because the package includes the spouted pouch, discoloration at the welded portion between the spout and the pouch can be sufficiently suppressed. This package allows high-precision digital printing to be fully utilized, further improving the quality of the product.

[0018] A method for producing a spout-equipped pouch according to one aspect of the present disclosure includes the steps of: preparing a laminate comprising, in this order, a base film, an adhesive layer constituted by at least one of an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound and a cured product thereof, and a sealant layer, with an electrostatic ink layer adhered to the adhesive layer; obtaining a packaging material by providing a sealed portion constituted by heat-sealing the sealant layers of the laminate and a non-sealed portion where the sealant layers face each other; and inserting a welding portion of a spout into the non-sealed portion of the packaging material and welding the welding portion to the sealant layer in the non-sealed portion.

[0019] In the laminate used in the above manufacturing method, the adhesive layer that adheres to the electrostatic ink layer is composed of at least one of an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound, and a cured product thereof. It is believed that such an adhesive layer has the effect of sufficiently aggregating the electrostatic ink composition that constitutes the electrostatic ink layer and improving adhesive strength. This effect is believed to occur when the epoxy compound penetrates from the adhesive layer into the electrostatic ink layer, crosslinking the epoxy compound and the electrostatic ink composition. Therefore, the laminate has excellent heat resistance, even while having an electrostatic ink layer composed of an electrostatic ink composition. Therefore, when a spout is welded to the laminate, flow of the electrostatic ink layer is sufficiently suppressed. Therefore, discoloration of the spout-equipped pouch at the welded portion with the spout can be sufficiently suppressed.

[0020] In the above manufacturing method, the welding of the welded portion and the sealant layer in the non-sealed portion may be performed by heating to 150° C. or higher, which can sufficiently suppress discoloration of the welded portion while ensuring sufficiently good sealing properties of the welded portion. [Effects of the Invention]

[0021] It is possible to provide a laminate that has excellent heat resistance while having an electrostatic ink layer made of an electrostatic ink composition. It is also possible to provide a spouted pouch, a method for manufacturing the same, and a package that can sufficiently suppress discoloration of the welded portion with the spout while having an electrostatic ink layer made of an electrostatic ink composition. It is also possible to provide a packaging material that is suitably used as the pouch body of such a spouted pouch. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a cross-sectional view showing an example of a laminate. [Figure 2] FIG. 10 is a cross-sectional view showing another example of a laminate. [Figure 3] FIG. 1 is a perspective view showing an example of a spouted pouch and a package. [Figure 4]FIG. 1 is a plan view showing an example of a packaging material for a spouted pouch. [Figure 5] FIG. 5 is a view of the spout shown in FIG. 4 as seen from the welded portion side. [Figure 6] (A) is a photograph showing the appearance of the evaluation sample after welding in Example 1. (B) is a photograph showing the appearance of the evaluation sample after welding in Example 2. [Figure 7] 1(A) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 1. FIG. 1(B) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 2. [Figure 8] 1(A) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 4. FIG. 1(B) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 5. [Figure 9] 1A is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 6. FIG. 1B is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0023] Embodiments of the present disclosure will be described below with reference to the drawings where appropriate. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. In the description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0024] Fig. 1 is a cross-sectional view schematically illustrating an example of a laminate. Fig. 1 shows a cross section along the lamination direction (thickness direction) of the laminate. The laminate 300 has a base film 10, a primer layer 40, an adhesive layer 30, and a sealant layer 20, in this order.

[0025] The substrate film 10 may be a flexible substrate. The flexible substrate may include, for example, one or both of a metal foil such as aluminum foil and a thermoplastic polymer film. Examples of flexible substrates include films of biaxially oriented polypropylene (BOPP), polyethylene terephthalate (PET), oriented polyamide (OPA), solid polypropylene (CPP), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and nylon.

[0026] The base film 10 may be, for example, a vapor-deposited film (transparent vapor-deposited film) in which aluminum, aluminum oxide, or the like is vapor-deposited on a PET film. The thickness of the base film 10 may be 7 to 150 μm, 15 to 90 μm, or 20 to 80 μm.

[0027] A typical sealant film can be used as the sealant layer 20. Examples of sealant films include CPP film, LLDPE film, and LDPE film. The thickness of the sealant layer 20 may be 7 to 150 μm, 15 to 90 μm, or 20 to 80 μm.

[0028] The primer layer 40 may contain a resin. Examples of the resin include polyvinyl alcohol resin, cellulose-based resin, polyester, polyamine, polyethyleneimine resin, polyamide resin, polyurethane, polyacrylic polymer, hydroxyl-containing resin, carboxyl-containing resin, and amine-based polymer. The presence of the primer layer 40 allows smooth printing of the electrostatic ink composition using a digital printer. It also improves the adhesion of the electrostatic ink layer 50. The amount of resin applied to form the primer layer 40 is, for example, 0.01 to 1.5 g / m. 2 and may be 0.05 to 1.0 g / m 2 may be.

[0029] The laminate 300 has a printing surface 52 on the primer layer 40. An electrostatic ink layer 50 is provided on the printing surface 52. The electrostatic ink layer 50 is provided between the adhesive layer 30 and the primer layer 40, with one side of the electrostatic ink layer 50 adhering to the adhesive layer 30 and the other side adhering to the primer layer 40. The electrostatic ink layer 50 may be composed of halftone dots of an electrostatic ink composition. The electrostatic ink layer 50 is provided by electrostatic printing using a digital printing machine. The multiple electrostatic ink layers 50 shown in FIG. 1 may have the same composition, or may have different compositions and thus different colors. The electrostatic ink layer 50 may be provided interspersed between the adhesive layer 30 and the primer layer 40, or may be provided to entirely cover one side of the adhesive layer 30 and one side of the primer layer 40.

[0030] The ink coverage on the printing surface 52 is not particularly limited and may be, for example, 10 to 500%, or may be 50 to 500%. In this specification, ink coverage represents the ratio of halftone dot area per unit area. For example, when a predetermined area is uniformly printed in a single color, the ink coverage is 100%. On the other hand, the ink coverage in an unprinted area is 0%. The ink coverage can be calculated based on these two values. When printing with multiple colors of ink, the ink coverage for each color of ink is calculated, and the sum of these values ​​can be used as the ink coverage of the target electrostatic ink layer. The ink coverage is set in a digital printing machine (e.g., HP's Indigo 20000 label and packaging digital printing machine) and can be adjusted by specifying a desired value in the ink coverage setting. The ink coverage on the printing surface 52 can also be confirmed by observing the printing surface 52 with an optical microscope.

[0031] The printing surface 52 having the electrostatic ink layer 50 is covered with an adhesive layer 30. The adhesive layer 30 may be composed of an adhesive composition, a cured product thereof, or a mixture thereof. The adhesive composition contains a polyol, a polyisocyanate, and an epoxy compound. At least a portion of these three components (polyol, polyisocyanate, and epoxy compound) may react with each other and cure to form a cured product. The polyurethane produced by the reaction of the epoxy compound contained in the adhesive layer 30 with the polyol and polyisocyanate may be crosslinked. This can improve the heat resistance of the adhesive layer 30.

[0032] The adhesive layer 30 containing the above three components and the electrostatic ink layer 50 are adhered to each other. The epoxy compound contained in the adhesive layer 30 may penetrate into the electrostatic ink layer 50, cross-linking the epoxy compound and the electrostatic ink composition. This allows the electrostatic ink composition to sufficiently cohere and improves adhesive strength. This also improves the heat resistance of the laminate 300.

[0033] Fig. 2 is a cross-sectional view showing another example of a laminate. The laminate 310 in Fig. 2 differs from the laminate 300 in Fig. 1 in that one entire surface of the adhesive layer 30 and one entire surface of the primer layer 40 are covered with an electrostatic ink layer 51. The other configurations of the laminate 310 may be the same as those of the laminate 300 in Fig. 1.

[0034] The electrostatic ink layers 50, 51 in FIGS. 1 and 2 are composed of circular halftone dots of an electrostatic ink composition. The color density of the printed surface 52 can be adjusted by changing the size of the halftone dots. In the laminates 300, 310, the electrostatic ink composition that constitutes the electrostatic ink layers 50, 51 composed of halftone dots is sufficiently cohesive and has high adhesive strength. As a result, the laminates 300, 310 have excellent heat resistance. Therefore, the laminates 300, 310 can be suitably used as a laminate (laminated film) for a spout-equipped pouch to which a spout is welded.

[0035] The electrostatic ink compositions constituting the electrostatic ink layers 50, 51 in the laminates 300, 310 are ink compositions used in liquid electrophotographic printing, i.e., electrostatic printing, and are printed onto substrates such as paper and plastic. The electrostatic ink composition may contain a colorant or pigment such as a dye and a resin. In addition to these, the electrostatic ink composition may also contain a carrier fluid or carrier liquid. It may also contain a charge director, a charge adjuvant, a surfactant, a viscosity modifier, an emulsifier, and other additives.

[0036] Examples of the colorant include cyan pigments, magenta pigments, yellow pigments, and black pigments. Examples of the resin include thermoplastic resins such as ethylene acrylic acid copolymers, propylene acrylic acid copolymers, ethylene methacrylic acid copolymers, propylene methacrylic acid copolymers, and ethylene vinyl acetate copolymers.

[0037] Carrier liquids include hydrocarbons, silicone oils, and vegetable oils. Hydrocarbons include aliphatic hydrocarbons, branched-chain aliphatic hydrocarbons, and aromatic hydrocarbons. The electrostatic ink composition may be substantially free of carrier liquid when printed onto a print substrate, such as a first substrate. The carrier liquid may be removed, for example, by an electrophoretic process or evaporation during printing, thereby transferring substantially only solids to the print substrate.

[0038] Charge directors serve to maintain a sufficient electrostatic charge on particles contained in the electrostatic ink composition, and include ionic compounds such as metal salts of fatty acids, metal salts of sulfosuccinates, metal salts of oxyphosphates, metal salts of alkylbenzene sulfonic acids, and metal salts of aromatic carboxylic or aromatic sulfonic acids, as well as zwitterionic and nonionic compounds such as polyoxyethylenated alkylamines, lecithin, polyvinylpyrrolidone, and organic acid esters of polyhydric alcohols.

[0039] Charge adjuvants have the effect of increasing or stabilizing the charge of particles contained in the electrostatic ink composition. Examples of charge adjuvants include barium petronate, calcium petronate, Co naphthenate, Ca naphthenate, Cu naphthenate, Mn naphthenate, Ni naphthenate, Zn naphthenate, Fe naphthenate, Ba stearate, Co stearate, Pb stearate, Zn stearate, Al stearate, Cu stearate, Fe stearate, and metal carboxylates.

[0040] The electrostatic ink composition may contain a crosslinked product crosslinked by components contained in the adhesive layer 30 and / or primer layer 40. This can sufficiently increase the strength of the electrostatic ink layer 50 itself, as well as the adhesive strength between the printing surface 52 and the electrostatic ink layer 50, and between the electrostatic ink layer 50 and the primer layer 40. In addition, during heat sealing, it is possible to prevent the dots constituting the electrostatic ink layer 50 from moving and to prevent gaps from forming at the interface between the electrostatic ink layer 50 and the adhesive layer 30. This can sufficiently prevent discoloration due to heat sealing.

[0041] The printed surface 52 of the electrostatic ink composition and the adhesive layer 30 are adhered to each other. That is, the electrostatic ink layers 50 and 51 made of the electrostatic ink composition are adhered to the adhesive layer 30 made of at least one of the adhesive composition and its cured product. This adhesive composition contains a polyol, a polyisocyanate, and an epoxy compound. These three components are described below.

[0042] The polyol has, for example, a number-average molecular weight of 400 or more and has two or more hydroxyl groups in one molecule. The polyisocyanate has two or more isocyanate groups in one molecule. The polyol and polyisocyanate react as a base resin and a curing agent, respectively, to produce polyurethane (polyurethane adhesive). The number-average molecular weight of the polyol may be, for example, 10,000 or less.

[0043] The polyol may contain at least one selected from the group consisting of polyester polyols and polyether polyols. Among these, from the viewpoint of sufficiently increasing the adhesive strength of the adhesive layer 30 in a high-temperature environment, the polyol may contain a polyester polyol or may contain an aliphatic polyester polyol.

[0044] The polyester polyol can be obtained, for example, by a condensation reaction or transesterification reaction between a polyhydric alcohol and a polybasic acid, its alkyl ester, its acid anhydride, or its acid halide. Examples of the polyhydric alcohol include low-molecular-weight diols, low-molecular-weight triols, and low-molecular-weight polyols having four or more hydroxyl groups.

[0045] 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, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 2,2-diethyl-1,3-propanediol, 3,3-dimethylolheptane, and 2-ethyl-2-butyl-1,3-propanediol.

[0046] Examples of low molecular weight triols include glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolethane, trimethylolpropane, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-(hydroxymethyl)pentane, and 2,2-bis(hydroxymethyl)-3-butanol.

[0047] Examples of low molecular weight polyols having four or more hydroxyl groups include tetramethylolmethane, pentaerythritol, dipentaerythritol, D-sorbitol, xylitol, D-mannitol, and D-mannite.

[0048] Examples of alkyl esters of polybasic acids include methyl esters and ethyl esters of polybasic acids. Examples of acid anhydrides include acid anhydrides derived from polybasic acids, such as oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, 2-alkyl (C12 to C18) succinic anhydride, tetrahydrophthalic anhydride, and trimellitic anhydride.

[0049] The acid halides include those derived from the above-mentioned polybasic acids, such as oxalic acid dichloride, adipic acid dichloride, and sebacic acid dichloride.

[0050] The polyether polyol may be a polyalkylene oxide. For example, it may be obtained by addition reaction of an alkylene oxide such as ethylene oxide and / or propylene oxide with a low molecular weight polyol as an initiator. Specific examples include polyethylene glycol, polypropylene glycol, and polyethylene polypropylene glycol (random or block copolymer). Other examples include polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran.

[0051] Examples of polyisocyanates include polyisocyanate monomers, polyisocyanate derivatives, and isocyanate-terminated prepolymers. The adhesive composition may contain multiple different polyisocyanates. The molar ratio (NCO / OH) of the isocyanate groups contained in the polyisocyanate to the hydroxyl groups of the polyol may be 0.5 to 10. Such an adhesive composition can form a cured product that has high adhesive strength and excellent flexibility.

[0052] Examples of the polyisocyanate monomer include aliphatic polyisocyanates, aromatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates.

[0053] Examples of aliphatic polyisocyanates include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), 1,5-pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methylcaprate.

[0054] Examples of the aromatic aliphatic polyisocyanate include xylylene diisocyanate derivatives, such as xylylene diisocyanate (1,3-xylylene diisocyanate or 1,4-xylylene diisocyanate) (XDI), tetramethyl xylylene diisocyanate (1,3-tetramethyl xylylene diisocyanate or 1,4-tetramethyl xylylene diisocyanate) (TMXDI), ω,ω'-diisocyanato-1,4-diethylbenzene, and polyol-modified xylylene diisocyanate obtained by reacting xylylene diisocyanate with trimethylolpropane.

[0055] The content of the xylylene diisocyanate derivative relative to the entire polyisocyanate may be 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more, from the viewpoint of improving the reactivity with the base agent (for example, polyol). By making it 30% by mass or more, the reactivity can be further increased.

[0056] Examples of alicyclic polyisocyanates include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorodiisocyanate) (IPDI), methylcyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate), and norbornane diisocyanate (NBDI).

[0057] Examples of polyisocyanate derivatives include polymers of the above-mentioned polyisocyanate monomers, allophanate-modified products, polyol-modified products, polyol-modified products produced by the reaction of a monomer with an alcohol, biuret-modified products, urea-modified products, oxadiazinetrione-modified products, carbodiimide-modified products, uretdione-modified products, and uretonimine-modified products.

[0058] The isocyanate-terminated prepolymer is a urethane prepolymer having at least two isocyanate groups at the molecular end. It can be obtained by subjecting at least one member selected from the group consisting of a polyisocyanate monomer, a polyisocyanate derivative, and an isocyanate-terminated prepolymer to a urethane reaction with a polyol. The molar ratio (NCO / OH) of the isocyanate groups contained in the polyisocyanate to the hydroxyl groups of the polyol may be 0.5 or more, 0.6 or more, 0.8 or more, 1 or more, or 1.5 or more. The molar ratio (NCO / OH) may be 10 or less, 5 or less, 4 or less, or 3 or less. Examples of numerical ranges for the molar ratio (NCO / OH) include 0.5 to 10, 0.5 to 5, 0.8 to 4, and 0.6 to 3.

[0059] The epoxy compound may be a compound having one 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, the epoxy compound may have epoxy groups at both ends. Examples of the epoxy compound include glycidyl ether type epoxy compounds, glycidyl amine type epoxy compounds, glycidyl ester type epoxy compounds, and alicyclic epoxy compounds (alicyclic epoxy compounds).

[0060] The molecular weight of the epoxy compound may be 500 or less, 450 or less, or 400 or less. Such an epoxy compound can sufficiently penetrate into the electrostatic ink composition that constitutes the electrostatic ink layer. The lower limit of the molecular weight of the epoxy compound may be, for example, 98.

[0061] Examples of the alicyclic epoxy compound include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate.

[0062] Examples of monofunctional alicyclic epoxy compounds having one epoxy group per molecule include 3,4-epoxycyclohexylmethyl methacrylate and 1,2-epoxy-4-vinylcyclohexane. Examples of bifunctional epoxy compounds having two epoxy groups per molecule include 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, and 4-vinylcyclohexene dioxide. Examples of epoxy compounds having one or more epoxy groups per molecule include the 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol represented by the following general formula (I):

[0063] [ka]

[0064] In the above general formula (I), n may be an integer of 1-4.

[0065] The epoxy compound preferably contains a bifunctional alicyclic epoxy compound. The bifunctionality increases the number of crosslinking points with the electrostatic ink composition and the primer resin, accelerating the curing reaction of the adhesive and facilitating curing. Furthermore, the alicyclic nature of the epoxy compound inhibits reaction with polyisocyanate due to steric hindrance. This allows for stable curing and ensures excellent adhesion at the interface between the printing surface 52 and the adhesive layer 30.

[0066] In the adhesive composition, the content of the epoxy compound per 100 parts by mass of polyol may be 3 to 25 parts by mass, 6 to 25 parts by mass, or 8 to 20 parts by mass, from the viewpoint of achieving both high adhesive strength and excellent shear suppression. If the content of the epoxy compound is too high, the excellent shear suppression 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 low, the adhesive strength under high-temperature hot water treatment conditions tends to decrease.

[0067] In the adhesive composition, the content of polyisocyanate per 100 parts by mass of polyol may be 10 to 50 parts by mass, 15 to 35 parts by mass, or 20 to 30 parts by mass, from the viewpoint of sufficiently increasing the seal strength and the adhesive strength under high-temperature hot water treatment conditions.

[0068] The molar ratio of the epoxy groups contained in the epoxy compound to the isocyanate groups contained in the polyisocyanate may be 0.5 to 10, 1.5 to 9, or 2.0 to 6.5, which allows a sufficiently high adhesive strength to be maintained under high-temperature hot water treatment conditions.

[0069] In addition to the above-mentioned components, the adhesive composition may contain optional components such as additives. Examples of additives include antioxidants, UV absorbers, light stabilizers, fillers, silane coupling agents, epoxy resins, catalysts, coatability improvers, leveling agents, nucleating agents, lubricants, release agents, antifoaming agents, plasticizers, surfactants, pigments, dyes, organic fine particles, inorganic fine particles, antifungal agents, and flame retardants. The adhesive composition may contain a solvent such as an organic solvent.

[0070] The adhesive composition bonds the print surface 52, on which the electrostatic ink composition is printed, to the sealant layer 20. An optional layer may be provided between the sealant layer 20 and the adhesive layer 30. In this case, the adhesive composition bonds the print surface 52 to the optional layer. The adhesive composition forms a urethane bond by reaction with the polyol and polyisocyanate, thereby functioning as an adhesive. Even in the presence of an epoxy compound, the formation of the urethane bond proceeds smoothly, allowing the print surface 52 to be bonded to the sealant layer 20 or any optional layer with sufficiently high adhesive strength.

[0071] The adhesive composition exhibits excellent adhesive strength at high temperatures and also has an excellent pot life. This allows for excellent workability during coating and lamination processes, such as bonding a printed surface to a substrate. The adhesive composition may contain a urethane-forming polyol and polyisocyanate, and an epoxy compound, at least a portion of which may be cured to form the adhesive layer 30. This allows for a reduction in the number of layers constituting the laminate 300 compared to when an adhesive layer containing only polyurethane and an epoxy coating layer are separately provided. Therefore, when producing a laminate using a roll-to-roll process, for example, problems such as roll meandering after aging and wrinkling due to blocking do not occur. Furthermore, the aging process after coating can be eliminated, improving manufacturing efficiency.

[0072] In laminates 300, 310 in which the electrostatic ink layers 50, 51 and the adhesive layer 30 are in direct contact, components such as epoxy compounds and / or polyisocyanates contained in the adhesive composition may penetrate into the electrostatic ink layers 50, 51. This crosslinks the electrostatic ink composition constituting the electrostatic ink layers 50, 51, causing the electrostatic ink composition (electrostatic ink layers 50, 51) to aggregate and improve strength at high temperatures. It also improves the adhesive strength between adjacent layers. Even if the printed surface 52 includes a plain area (transparent area) without the electrostatic ink layer 50, as shown in FIG. 1, the epoxy compound contained in the adhesive layer 30 can eliminate stickiness. On the other hand, if an epoxy coating layer is provided separately from the adhesive layer 30, when the printed surface 52 includes a plain area, excess epoxy compound may be present near the plain area, making stickiness more likely. In this way, the laminate 300 can adhere the printed surface 52, including the plain area without the electrostatic ink layer 50, with high adhesive strength while eliminating stickiness.

[0073] The laminates 300, 310 have an electrostatic ink layer 50 with excellent high-temperature strength and also have excellent adhesive strength at high temperatures. Therefore, when the laminates 300, 310 are welded to the spout, the electrostatic ink layer 50 is sufficiently prevented from flowing and moving. This effectively prevents discoloration at the welded portion with the spout. The thickness of the laminates 300, 310 may be, for example, 15 to 200 μm, or 18 to 120 μm.

[0074] The laminate according to the modified example may not have the primer layer 40, or may have a primer layer 40 on each of the opposing surfaces of the base film 10 and the sealant layer 20. Furthermore, from the viewpoint of improving the gas barrier property and water vapor barrier property of the laminate 300, 310, at least one of a metal layer such as an aluminum foil and a resin layer such as a nylon film may be present between the base film 10 and the sealant layer 20 and / or between the sealant layer 20 and the adhesive layer 30.

[0075] Specific examples of the layer structure of the laminate are shown below. In each example, the base film 10 is on the left end and the sealant layer 20 is on the right end, with the layers laminated in order from left to right. The first adhesive layer is adhesive layer 30. The second adhesive layer and the third adhesive layer may be adhesive layers similar to adhesive layer 30, or may be different, ordinary adhesive layers.

[0076] (1) Transparent vapor-deposited PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / CPP film (non-oriented polypropylene film) (2) PET film / primer layer / electrostatic ink layer / first adhesive layer / aluminum layer / second adhesive layer / CPP film (non-oriented polypropylene film) (3) Nylon layer / primer layer / electrostatic ink layer / first adhesive layer / LLDPE (linear low-density polyethylene) film (4) PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / CPP film (5) PET film / primer layer / electrostatic ink layer / first adhesive layer / LLDPE film (6) Transparent vapor-deposited PET film / primer layer / electrostatic ink layer / first adhesive layer / CPP film (7) PET film / primer layer / electrostatic ink layer / first adhesive layer / aluminum vapor deposition barrier film / LLDPE film (8) OPP film / primer layer / electrostatic ink layer / first adhesive layer / aluminum vapor deposition barrier film / second adhesive layer / CPP film (9) PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / LLDPE film (10) Transparent vapor-deposited PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / LLDPE film (11) Transparent vapor-deposited PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / LDPE film (12) PET film / primer layer / electrostatic ink layer / first adhesive layer / aluminum layer / second adhesive layer / nylon layer / third adhesive layer / LLDPE film (13) PET film / primer layer / electrostatic ink layer / first adhesive layer / aluminum layer / second adhesive layer / nylon layer / third adhesive layer / LDPE film (14) PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / aluminum layer / third adhesive layer / LLDPE film (15) PET film / primer layer / electrostatic ink layer / first adhesive layer / nylon layer / second adhesive layer / aluminum layer / third adhesive layer / LDPE film

[0077] In each of the above specific examples, the primer layer may be omitted, or any layer may be provided at any position.

[0078] A method for manufacturing a laminate according to one embodiment is described below. In this manufacturing method, a laminate 300 shown in Fig. 1 is manufactured. The manufacturing method includes the steps of forming a primer layer 40 on one surface of a substrate film 10, printing an electrostatic ink composition on the primer layer 40 to form an electrostatic ink layer 50 to obtain a printed surface 52, and bonding the printed surface 52 to one surface of a sealant layer 20 using an adhesive composition.

[0079] The primer layer 40 may be formed on one side of the substrate film 10 by flexographic printing, gravure printing, or the like. The primer layer 40 may be formed by crosslinking a resin raw material with a crosslinking agent. Crosslinking may be achieved by irradiation with ultraviolet light, heat, ionizing radiation such as an electron beam, or non-ionizing radiation such as microwave radiation. The electrostatic ink composition can be printed by electrostatic printing using a digital printer. As a digital printer, for example, the Indigo 20000 label and packaging digital printer manufactured by HP can be used. In this manner, the electrostatic ink layer 50 is formed, and the printed surface 52 is obtained.

[0080] The adhesive composition can be used to bond the printing surface 52 to one side of the sealant layer 20 by lamination. Lamination can be performed using any suitable device. The epoxy compound and / or polyisocyanate contained in the adhesive composition may penetrate into the electrostatic ink composition and primer layer 40 that make up the electrostatic ink layer 50 and undergo a cross-linking reaction with the components contained in the electrostatic ink composition and primer layer 40. This improves the strength of the electrostatic ink layer 50 and allows for the production of a laminate 300 in which the interfaces of the layers are sufficiently bonded. During lamination, at least a portion of the adhesive composition may be cured to form a cured product. In this manner, a laminate 300 can be produced that includes, in this order, the substrate film 10, the primer layer 40, the electrostatic ink layer 50, the adhesive layer 30, and the sealant layer 20. The laminate 310 and the laminates according to the variations can also be produced in the same manner as the laminate 300.

[0081] The laminates 300 and 310 thus manufactured have the same configurations and properties as those described in these embodiments. The description of the laminates 300 and 310 and their modifications also applies to the description of the above-described manufacturing method embodiment.

[0082] The laminates 300 and 310 are suitable for use as packaging materials (pouch bodies) for spouted pouches. Spouted pouches can be produced by using the laminates 300 and 310 as packaging materials.

[0083] 3 is a perspective view showing an example of a spout-equipped pouch and a package. The spout-equipped pouch 100 comprises a pouch main body 110 having a so-called side gusset type shape, and a spout 120 welded to the upper end of the pouch main body 110. The pouch main body 110 has a seal section 101 formed by bonding the sealant layers 20 of multiple laminates 300 (310) together by heat sealing. The seal section 101 forms a bag capable of accommodating packaged items.

[0084] The spouted pouch 100 can accommodate an article 202 (e.g., a beverage) inside the pouch main body 110. This makes it possible to obtain a package 200 that accommodates the article 202. That is, the package 200 comprises the spouted pouch 100 and the article 202 that is accommodated in a storage section formed by the seal section 101 of the pouch main body 110.

[0085] 4 is a plan view showing packaging material 140 for a spout-equipped pouch and spout 120 welded thereto. The outer edge of packaging material 140, which will become pouch main body 110, is provided with sealed section 101 formed by heat-sealing laminates 300 (310) together, and non-sealed section 102 to which welded section 126 of spout 120 is welded. In sealed section 101, sealant layers 20 are bonded together by heat sealing. In contrast, in non-sealed section 102, sealant layers 20 are not bonded together, and are arranged opposite each other. In other words, non-sealed section 102 is a through-hole that connects the inside and outside of pouch main body 110.

[0086] The spout 120 has a cylindrical portion 122 forming a flow path through which the packaged item flows, a welding portion 126 provided at the lower end of the cylindrical portion 122, and a lid 121 screwed to the upper end of the cylindrical portion 122. A plurality of welding ribs 126r are formed in the form of horizontal stripes in the welding portion 126 to strengthen the welding between the welding portion 126 and the packaging material 140. However, the spout 120 is not limited to having the welding ribs 126r, and the welding ribs 126r may be omitted. A flange 124 and a flange 123 are formed in this order from the welding portion 126 side on the outer peripheral surface of the cylindrical portion 122 so as to extend laterally of the cylindrical portion 122. The cylindrical portion 122, the welding portion 126, the flange 124, and the flange 123 may be molded integrally using a synthetic resin. Examples of such synthetic resins include high-density polyethylene resin (HDPE), low-density polyethylene resin (LDPE), linear low-density polyethylene resin (L-LDPE), polypropylene resin (PP), polyester resin, vinyl chloride resin, ABS resin, etc. The lid 121 may also be a molded product made from the above-mentioned synthetic resin.

[0087] The spout-equipped pouch 100 can be manufactured by welding the welding portion 126 of the spout 120 to the non-sealed portion 102 of the packaging material 140 in Fig. 4. The welding is performed by applying heat and pressure to the welding portion 126 and the sealant layer 20 of the laminate 300 (310) in a state where they are superimposed on each other.

[0088] FIG. 5 is a view of the spout 120 as viewed from the welded portion 126 side. That is, it is a view of the spout 120 shown in FIG. 4 as viewed from below toward above. The welded portion 126 of the spout 120 has a diamond-shaped planar shape. The welded rib 126r formed in the welded portion 126 protrudes outward beyond the portion other than the welded rib 126r. This ensures that the welded portion 126 is welded securely to the sealant layer 20 in the non-sealed portion 102, improving the sealing performance of the welded portion 150. A flow path 128 for the packaged item is formed in the center of the welded portion 126. This flow path 128 can be used to fill the storage portion of the spouted pouch with the packaged item or to remove the packaged item from the storage portion.

[0089] When welding the sealant layer 20 of the laminate 300 (310) to the welding portion 126, the laminate 300 (310) is positioned so that the welding portion 126 and the sealant layer 20 are in contact with each other, sandwiching the welding portion 126. Then, a heated mold or the like is used to press the laminate 300 (310) along the surface of the welding portion 126. This causes the sealant layer 20 to be welded to the welding portion 126, resulting in a spouted pouch. During this process, the portion of the laminate 300 (310) that is welded to the welding portion 126 is exposed to high temperatures while being pressurized. Therefore, if the electrostatic ink layer contained in the laminate has low heat resistance, the electrostatic ink layer will melt and flow, migrating from the pressurized portion to the non-pressurized portion. This melting and migration of the electrostatic ink layer will result in discoloration of the welded portion 150 in FIG. 3 .

[0090] The electrostatic ink layer 50 (51) in the laminate 300 (310) is well cohesive and has excellent adhesive strength, resulting in excellent heat resistance. This prevents the electrostatic ink layer 50 (51) from melting and flowing when it is welded to the welded portion 126. This effectively prevents discoloration of the welded portion 150.

[0091] The shapes of the spout and spout-equipped pouch are not limited to those shown in the drawings. For example, the welded portion 126 of the spout may have a circular or elliptical planar shape instead of a diamond shape. Furthermore, the packaging material 140 (pouch main body 110) may have a shape other than a side gusset type. For example, it may have the shape of a two-sided bag, a three-sided bag, a four-sided bag, or a two-sided bag.

[0092] The procedure for manufacturing a packaging material using the laminate 300 (310) is described below. One or more laminates 300 (310) cut to a predetermined shape are prepared according to the shape of the packaging material (pouch body) to be manufactured. The sealant layers 20 provided on one side of the laminates 300 (310) are placed opposite each other, and the sealant layers 20 are heat-sealed to bond them together. A packaging material (pouch body 110) having a side gusset type shape as shown in Figures 3 and 4 may be manufactured. In this way, a packaging material 140 is formed, as shown in Figure 4, having a sealed portion 101 formed by heat sealing at the outer edge and an unsealed portion 102 where the sealant layers 20 are arranged opposite each other.

[0093] The welded portion 126 of the spout 120 is inserted into a through hole formed by the non-sealed portion 102 that communicates the inside and outside of the packaging material 140, and heat and pressure are applied with the welded portion 126 sandwiched between a pair of laminates 300 to weld the welded portion 126 to the sealant layer 20 of the laminate 300 (310). In this manner, a spouted pouch 100 having a welded portion 150 as shown in Figure 3 can be manufactured. The lid 121 of the spout 120 of this spouted pouch 100 is opened, the contents to be packaged are filled, and the pouch is sealed with the lid 121 to obtain a packaged body 200 as shown in Figure 3.

[0094] The heating temperature when welding the welded portion 126 and the sealant layer 20 may be 150°C or higher, 170°C or higher, or 190°C or higher. This allows the welded portion 126 of the spout 120 and the sealant layer 20 to be welded sufficiently firmly, thereby sufficiently increasing the sealing performance of the welded portion 150. Furthermore, even when welding is performed at such a temperature, discoloration of the welded portion 150 can be sufficiently suppressed. The upper limit of the heating temperature may be 220°C or lower, from the viewpoint of the heat resistance of the laminate 300 (310) and the welded portion 126.

[0095] The laminate 300 (310) has excellent heat resistance despite having the electrostatic ink layer 50 (51), and is therefore suitable for use with foods that are heated with hot water. The package 200 may be used as a package for ordinary beverages, etc., or as a package for boiling or retort pouches.

[0096] Although several embodiments have been described above, the present disclosure is not limited to the above embodiments. [Example]

[0097] The present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to the following examples.

[0098] Example 1 [Laminate fabrication] A nylon film (manufactured by Unitika Ltd., product name: Emblem ONM, thickness: 15 μm) was prepared as the substrate film. An aqueous primer resin (a resin containing polyethyleneimine, manufactured by Michelman, product name: DP050) was applied to one side of this nylon film to form a primer layer. The amount of the aqueous primer resin applied was 0.10 to 0.18 g / m. 2 The coating was applied so that

[0099] An electrostatic ink layer was formed by printing on the surface of the primer layer using a digital printer (HP Indigo 20000 label and packaging digital printer). The electrostatic ink composition used was an electrostatic ink composition (HP Indigo Electroink) containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid. The color of the electrostatic ink composition was black. The ink coverage was set to 200% by the settings of the digital printer.

[0100] An adhesive composition with a solids concentration of 36.5% by mass was prepared using an aliphatic polyester polyol (manufactured by Mitsui Chemicals, Inc., trade name: Takelac A626, hereinafter sometimes referred to as "component (A)") as the base agent, a polyisocyanate (manufactured by Mitsui Chemicals, Inc., trade name: Takenate A50, hereinafter sometimes referred to as "component (B)") as the curing agent, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (hereinafter sometimes referred to as "component (C)") as the epoxy compound, and ethyl acetate as the solvent. The structure of this epoxy compound is shown in formula (1) below. The mass-based blending ratio of each component was (A) component:(B) component:(C) component = 8:1:0.28.

[0101] The adhesive composition prepared as described above was applied to the surface printed with the electrostatic ink composition using a dry laminating device to form an adhesive layer. The amount of the adhesive composition applied was 4.0 g / m. 2 It was decided.

[0102] [ka]

[0103] Using the dry laminating device, the adhesive layer on the substrate film was bonded to a linear low-density polyethylene film (manufactured by Mitsui Chemicals Tohcello Inc., product name: TUX-FCS, thickness: 60 μm) that would serve as a sealant layer, with the adhesive layer facing the linear low-density polyethylene film. The curing time (aging) was 40°C for 2 days. In this way, a laminate having the laminate structure shown in Figure 2 was obtained.

[0104] [Preparation of evaluation samples and evaluation of discoloration and welding condition] A polyethylene spout having the shape shown in Figs. 3 to 5 was prepared. The spout's welded portion was sandwiched between a pair of laminates so that the welded portion and the sealant layer were in contact with each other, to prepare a sample for evaluation. Using a thermal gradient tester (manufactured by Toyo Seiki Seisakusho, device name: HG-3), heating and pressure were applied for 1.0 second under conditions of a temperature of 200°C and a pressure of 0.3 MPa, to weld the welded portion and the sealant layer. Pressure was applied in the direction in which the welded portion and the sealant layer faced each other. The welded portion was welded over a set area (75 mm 2 ) and calculated the area of ​​the discolored area detected visually due to ink loss. The results are shown in Table 1. The welding condition between the welded part of the spout and the sealant layer was also evaluated. A strong seal between the welded part of the spout and the sealant layer was evaluated as "A," and an insufficient seal was evaluated as "B." The results are shown in Table 1.

[0105] Example 2 Except for using cyan and magenta as the electrostatic ink composition colors in overprinting and setting the ink coverage to 300%, a laminate and an evaluation sample were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0106] Example 3 Except for using white as the color of the electrostatic ink composition and setting the ink coverage to 100%, a laminate and an evaluation sample were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0107] (Comparative Example 1) Except for not blending the epoxy compound (component (C)) when preparing the adhesive composition, laminates and evaluation samples were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0108] (Comparative Example 2) Except for not blending the epoxy compound (component (C)) when preparing the adhesive composition, laminates and evaluation samples were prepared and evaluated in the same manner as in Example 2. The results are shown in Table 1.

[0109] (Comparative Example 3) Except for not blending the epoxy compound (component (C)) when preparing the adhesive composition, a laminate and an evaluation sample were prepared and evaluated in the same manner as in Example 3. The results are shown in Table 1.

[0110] [Table 1]

[0111] Fig. 6(A) is a photograph showing the appearance of the evaluation sample after welding in Example 1. Fig. 6(B) is a photograph showing the appearance of the evaluation sample after welding in Example 2. As shown in Fig. 6, no discoloration occurred in Examples 1 and 2. Similarly to Examples 1 and 2, no visually detectable discoloration occurred in Example 3. Furthermore, in all of the evaluation samples of Examples 1 to 3, the welded portion of the spout and the sealant layer were firmly welded.

[0112] Fig. 7(A) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 1. Fig. 7(B) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 2. As shown in Fig. 7, in Comparative Examples 1 and 2, ink loss occurred and obvious discoloration occurred. In Comparative Example 3, ink loss also occurred and discoloration occurred. In all of the evaluation samples of Comparative Examples 1 to 3, the welded portion of the spout and the sealant layer were firmly welded.

[0113] (Comparative Examples 4 to 7) Laminates and evaluation samples were prepared and welding evaluation was carried out in the same manner as in Comparative Example 1, except that the temperature when welding the welded portion of the spout and the sealant layer was changed as shown in Table 2. The results are shown in Table 2. Table 2 also shows the results of Comparative Example 1 described above.

[0114] [Table 2]

[0115] Fig. 8(A) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 4. Fig. 8(B) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 5. Fig. 9(A) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 6. Fig. 9(B) is a photograph showing the appearance of the evaluation sample after welding in Comparative Example 7. As shown in Table 2, Figs. 8 and 9, although the discolored area can be reduced by lowering the welding temperature, it was confirmed that if the welding temperature was lowered too much, the welding between the welded portion and the sealant layer became insufficient.

[0116] The results of the above-mentioned Examples and Comparative Examples confirmed that the use of an adhesive composition containing a polyol, a polyisocyanate, and an epoxy compound can suppress discoloration caused by ink loss during welding. The reason for this suppression of discoloration is thought to be the improved heat resistance due to the improved cohesion and adhesive strength of the electrostatic ink composition. To verify this, the following experiment was conducted.

[0117] Example 4 [Adhesive composition and preparation of laminate] A polyethylene terephthalate film (PET film, thickness: 12 μm) was prepared as a substrate film. The same aqueous primer resin as in Example 1 was applied to one side of this PET film to form a primer layer. The amount of the aqueous primer resin applied was also the same as in Example 1.

[0118] A predetermined printing was performed on the surface of the primer layer using the digital printing machine used in Example 1. The electrostatic ink composition used was an electrostatic ink composition (HP Indigo Electroink) containing a thermoplastic resin containing a copolymer of ethylene acrylic acid and ethylene methacrylic acid. The colors of the electrostatic ink composition used were white (W), yellow (Y), magenta (M), and cyan (C), as shown in Table 3. Multiple samples with different colors and ink coverage rates of the electrostatic ink composition were prepared. The ink coverage rates of each color and their total were as shown in Table 3. As shown in Table 3, the total ink coverage rate was 200 to 500%.

[0119] The same adhesive composition as in Example 1 was prepared, and the adhesive composition was applied to the printed surface in the same manner as in Example 1 to form an adhesive layer. The amount of adhesive composition applied was 4.0 g / m 2 It was decided.

[0120] A laminated film having an aluminum foil (manufactured by Toyo Aluminum Co., Ltd., thickness: 7 μm), a nylon film, and an unstretched polypropylene film in this order was prepared. Using the same dry laminating device as in Example 1, the adhesive layer on the base film and the aluminum foil of the laminated film were placed facing each other, and the aluminum foil and the adhesive layer were bonded together to obtain a laminate. The curing time (aging) was 40°C for 2 days.

[0121] [Measurement of adhesive strength (room temperature)] The adhesive strength of the prepared laminate was measured in accordance with JIS K 6854-1:1999. Specifically, the prepared laminate was cut into a 15 mm width to prepare a measurement sample. After peeling between the layers at the edge of the measurement sample, the peel strength between the layers of the laminate was measured using a tensile tester at an angle of 90°, a tensile speed of 300 mm / min, and room temperature. This peel strength was defined as the adhesive strength at room temperature (20°C). The measurement results are shown in Table 3.

[0122] (Examples 5 to 9) Laminates were prepared and adhesive strengths were measured in the same manner as in Example 4, except that the formulation of the adhesive composition was changed as shown in Tables 3 and 4. The measurement results are shown in Tables 3 and 4.

[0123] Example 10 A two-component adhesive was prepared in which a first component consisting of component (A) used in Example 1 and a second component consisting of components (B) and (C) were housed in separate containers. The first and second components were mixed to prepare an adhesive composition having the formulation shown in Table 4. A laminate was produced in the same manner as in Example 4, except that this adhesive composition was used, and the adhesive strength was measured. The measurement results are shown in Table 4.

[0124] (Comparative Example 8) A laminate was produced in the same manner as in Example 4, except that component (C) was not added when preparing the adhesive composition, and the adhesive strength was measured. The measurement results are shown in Table 4.

[0125] Comparative Example 9 A laminate was produced in the same manner as in Example 4, except that an epoxy compound of formula (1) was applied to the surface printed with the electrostatic ink composition to form an epoxy coating layer, and the adhesive composition of Comparative Example 8 was applied to this epoxy coating layer, and the adhesive strength was measured. The amount of the epoxy coating layer applied was an amount equivalent to 0.53 parts by mass in the formulation shown in Table 4. The measurement results are shown in Table 4.

[0126] [Table 3]

[0127] [Table 4]

[0128] The column [(B) / (A)] × 100 in Tables 3 and 4 shows the amount (parts by mass) of component (B) relative to 100 parts by mass of component (A). The column [(C) / (A)] × 100 in Tables 3 and 4 shows the amount (parts by mass) of component (C) relative to 100 parts by mass of component (A). The column "Epoxy group / Isocyanate group" in Tables 3 and 4 shows the molar ratio of epoxy groups in component (C) to isocyanate groups in component (B).

[0129] As shown in Tables 3 and 4, it was confirmed that the laminates of Examples 4 to 10, in which an adhesive layer containing an epoxy compound was bonded to a printed surface, had higher adhesive strength than the laminate of Comparative Example 8, in which an adhesive layer not containing an epoxy compound was bonded to a printed surface. Comparative Example 9 achieved relatively high adhesive strength, but the number of steps increased because an epoxy coating layer was formed in addition to the adhesive layer. It took two days for the epoxy coating layer to harden (age), reducing productivity.

[0130] In the laminate of Comparative Example 8, peeling occurred near the interface between the electrostatic ink layer and the primer layer. In the laminate of Comparative Example 9, the electrostatic ink layer underwent cohesive failure. On the other hand, in the laminates of Examples 4 to 10, peeling occurred 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 strength and adhesive strength of the electrostatic ink layer were improved. In Examples 4 to 10, the molar ratio of isocyanate groups contained in component (B) to hydroxyl groups in component (A) was within the range of 0.5 to 10.

[0131] Next, the adhesive strength, hot water adhesive strength, and seal strength of the laminates of Example 8 and Comparative Example 9 were measured. For the measurements, samples with a total ink coverage of 500% and 200% were used. The details of the measurement procedure are as follows.

[0132] [Measurement of hot water adhesive strength] The laminates of Example 8 and Comparative Example 9 were each cut to a width of 15 mm to obtain a measurement sample. After peeling between the layers at the edge of the measurement sample, the sample was immersed in hot water at 90°C and the peel strength was measured using a tensile tester. Specifically, the peel angle was free and the tensile speed was 300 mm / min. This peel strength is shown in Table 5 as the hot water adhesion strength.

[0133] [Measurement of seal strength (before heat treatment)] Using a pair of laminates from Example 8, the unstretched polypropylene films were overlapped and heat-sealed to form a sealed portion. This welded the unstretched polypropylene films together, producing a 15 mm wide measurement sample. The seal strength of the sealed portion of the prepared measurement sample was measured in accordance with JIS K 7127:1999. The peel strength between the heat seals was measured using a tensile tester under the following conditions: a peel angle of 90°, a tensile speed of 300 mm / min, and room temperature (20°C). This peel strength was defined as the seal strength "before heat treatment." The measurement results are shown in Table 5. A similar measurement sample was prepared using the laminate from Comparative Example 10, and similar measurements were performed. The measurement results are shown in Table 5.

[0134] [Seal strength measurement (after boiling)] The measurement samples prepared in the above "Measurement of seal strength (before heat treatment)" were heated in water at 100°C for 30 minutes. Thereafter, the seal strength was measured using the same procedure as in the above "Measurement of seal strength (without heat treatment)". The measurement results are shown in the "After boiling" column in Table 5.

[0135] [Measurement of seal strength after retort (120℃)] The measurement samples prepared in the "Measurement of seal strength (before heat treatment)" section above were subjected to retort heat treatment (120°C x 30 minutes). Peel strength was measured using a tensile tester in the same manner as in "Measurement of seal strength (before heat treatment)." The measurement results are shown in the "120°C x 30 minutes" section of Table 5.

[0136] [Measurement of seal strength after retort (130℃)] The measurement samples prepared in the above "Measurement of seal strength (before heat treatment)" were subjected to retort heat treatment (130°C x 30 minutes). Peel strength was measured using a tensile tester in the same manner as in "Measurement of seal strength (without heat treatment)". The measurement results are shown in the "130°C x 30 minutes" column in Table 5.

[0137] [Table 5]

[0138] As shown in Table 5, the hot water adhesive strength of Example 8 was significantly higher than that of Comparative Example 9. It was also confirmed that Example 8 had better seal strength than Comparative Example 9. In particular, the seal strength of Example 8 was sufficiently high even after boiling, whereas the seal strength of Comparative Example 9 decreased significantly after boiling. It was confirmed that the adhesive strength and seal strength of the laminate of Comparative Example 9 decreased significantly when heated in the presence of moisture.

[0139] Example 11 [Adhesive composition and preparation of laminate] A polyethylene terephthalate film (PET film, thickness: 12 μm) was prepared as a substrate film. The same aqueous primer resin as in Example 1 was applied to one side of this PET film to form a primer layer. The amount of the aqueous primer resin applied was also the same as in Example 1.

[0140] Using the digital printing machine used in Example 1, a predetermined printing was performed on the surface of the primer layer. The colors of the electrostatic ink composition used were white (W), yellow (Y), magenta (M), and cyan (C). Two ink coverage ratios were prepared: one with W 200% and the other with C 100% + M 100% + Y 100% + W 200%. In Table 6, the former is referred to as "ink coverage ratio (1)," and the latter is referred to as "ink coverage ratio (2)." In this way, two types of samples with different ink coverage ratios of the electrostatic ink composition were prepared.

[0141] The same adhesive composition as in Example 1 was prepared, and the adhesive composition was applied to the printed surface in the same manner as in Example 1 to form an adhesive layer. The amount of adhesive composition applied was 4.0 g / m 2 It was decided.

[0142] The laminated film used in Example 4 (a laminated film obtained by laminating a nylon film and an unstretched polypropylene film with a commercially available adhesive) was attached to the adhesive layer of the base film to obtain a laminate in the same manner as in Example 4. The curing time (aging) was 40°C for 2 days.

[0143] The seal strength (before heat treatment) and seal strength (after boiling) of the laminate thus obtained were measured. The measurement results are shown in Table 6. In addition, the adhesive strength (before heat treatment) and hot adhesive strength (120°C) were measured by the following procedure.

[0144] A pair of laminates from Example 11 was heat-sealed with the unstretched polypropylene films overlapping each other to produce a three-sided bag with a sealed section. Water was then sealed into the three-sided bag. A retort heat treatment (120°C x 30 minutes) was then performed using a retort treatment device (manufactured by Hisaka Works, Ltd.). After the retort heat treatment, a sample was cut to a width of 15 mm to obtain a sample from the sealed section, 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 "Hot Adhesion Strength (120°C)" column in Table 6. Table 6 also shows the adhesive strength before the retort heat treatment.

[0145] Examples 12 to 15 A laminate was produced in the same manner as in Example 11, except that when preparing the adhesive composition, the amount of polyisocyanate (B) was changed as shown in Table 6. The produced laminate was evaluated in the same manner as in Example 11. The evaluation results are shown in Table 6.

[0146] (Comparative Example 10) A laminate was produced in the same manner as in Comparative Example 8, except that lamination of the surface printed with the electrostatic ink composition was performed using a hand laminator instead of a dry laminator. The color and ink coverage of the electrostatic ink composition were as shown in Table 6. The produced laminate was evaluated in the same manner as in Example 11. The evaluation results are shown in Table 6.

[0147] [Table 6]

[0148] As shown in Table 6, it was confirmed that high adhesive strength and seal strength were obtained in each Example even under heating conditions. It was also confirmed that hot adhesive strength (120°C) and seal strength (before heat treatment and after boiling) could be sufficiently increased by adjusting the blending ratio of component (B) to component (A). On the other hand, it was confirmed that in Comparative Example 10, which did not use component (C), the adhesive strength and seal strength were significantly reduced when exposed to high-temperature hot water treatment conditions. In Examples 11 to 15, the molar ratio of isocyanate groups contained in component (B) to hydroxyl groups contained in component (A) was within the range of 0.5 to 10.

[0149] (Examples 16 to 20) An adhesive composition was prepared by blending an aliphatic polyester polyol (A1) (Takelac A525, manufactured by Mitsui Chemicals, Inc.), a polyisocyanate (B1) (Takenate A52, manufactured by Mitsui Chemicals, Inc.), and 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate as the epoxy compound (C). The blending ratios were as shown in Table 7. Laminates were produced and evaluated in the same manner as in Examples 11 to 15, except that such adhesive compositions were used. The evaluation results were as shown in Table 7.

[0150] (Comparative Example 11) An adhesive composition was prepared by blending an aliphatic polyester polyol (A1) (Takelac A525, manufactured by Mitsui Chemicals, Inc.) as a polyol and a polyisocyanate (B1) (Takenate A52, manufactured by Mitsui Chemicals, Inc.). The blending ratios were as shown in Table 7. A laminate was produced and evaluated in the same manner as in Comparative Example 10, except that such an adhesive composition was used. The evaluation results are shown in Table 7.

[0151] [Table 7]

[0152] As shown in Table 7, it was confirmed that high adhesive strength and seal strength were obtained in each Example even when the combination of aliphatic polyester polyol and polyisocyanate was changed. It was also confirmed that the seal strength (without heat treatment and after boiling) and hot adhesive strength (120°C) could be sufficiently increased by adjusting the blending ratio of polyisocyanate (B1) to aliphatic polyester polyol (A1). On the other hand, it was confirmed that in Comparative Example 11, which did not use epoxy compound (C), the adhesive strength and seal strength were significantly reduced when exposed to high-temperature hot water treatment conditions. In Examples 16 to 20, the molar ratio of isocyanate groups contained in polyisocyanate (B1) to hydroxyl groups contained in aliphatic polyester polyol (A1) was within the range of 0.5 to 10. [Industrial Applicability]

[0153] According to the present disclosure, a laminate having excellent heat resistance while having an electrostatic ink layer made of an electrostatic ink composition is provided. Also provided are a spouted pouch having an electrostatic ink layer made of an electrostatic ink composition and capable of sufficiently suppressing discoloration of the welded portion, a method for manufacturing the same, and a package. Furthermore, a packaging material suitable for use as the pouch body of such a spouted pouch is provided. [Explanation of symbols]

[0154] 10...base film, 20...sealant layer, 30...adhesive layer, 40...primer layer, 50, 51...electrostatic ink layer, 52...printed surface, 100...pouch with spout, 101...sealed portion, 102...non-sealed portion, 110...pouch main body, 120...spout, 121...lid body, 122...tubular portion, 123...flange, 124...flange, 126...welded portion, 126r...welded rib, 128...flow path, 140...packaging material, 150...welded portion, 200...packaging body, 202...packaged item, 300, 310...laminated body.

Claims

1. A laminate for a spout-equipped pouch, comprising a base film, an adhesive layer, and a sealant layer welded to a spout in this order, and an electrostatic ink layer adhered to the adhesive layer on the base film side, The adhesive layer is a laminate comprising at least one of an adhesive composition containing a polyol, a polyisocyanate, and a bifunctional alicyclic epoxy compound having epoxy groups at both ends and a molecular weight of 500 or less, and a cured product thereof.

2. The laminate according to claim 1 , further comprising a primer layer between the substrate film and the electrostatic ink layer.

3. The laminate according to claim 1 or 2, wherein the polyol includes an aliphatic polyester polyol, and the alicyclic epoxy compound includes one having epoxy groups at both ends.

4. 4. The laminate according to claim 1, wherein the alicyclic epoxy compound permeates the electrostatic ink layer and crosslinks the electrostatic ink composition contained in the electrostatic ink layer.

5. The laminate according to any one of claims 1 to 4, wherein the polyisocyanate comprises a xylylene diisocyanate derivative.

6. A packaging material for a spout-equipped pouch, comprising: a sealed portion formed by heat-sealing the sealant layers of the laminate according to any one of claims 1 to 5; and a non-sealed portion where the sealant layers face each other and the spout is welded.

7. A pouch body having a seal portion in which the sealant layers in the laminate according to any one of claims 1 to 5 are bonded together and having a storage portion for storing an item to be packaged; a spout welded to the sealant layer of the laminate in the pouch body.

8. A package comprising the spouted pouch according to claim 7 and an item to be packaged housed therein.

9. a step of preparing a laminate comprising a substrate film, an adhesive layer constituted in this order by an adhesive composition containing a polyol, a polyisocyanate, and a bifunctional alicyclic epoxy compound having epoxy groups at both ends and a molecular weight of 500 or less, and a cured product thereof, and a sealant layer, the laminate comprising an electrostatic ink layer adhered to the substrate film side of the adhesive layer; a step of obtaining a packaging material by providing a sealed portion formed by heat-sealing the sealant layers of the laminate and a non-sealed portion where the sealant layers face each other; inserting a welding portion of a spout into the non-sealed portion of the packaging material and welding the welding portion to the sealant layer in the non-sealed portion.

10. The method for producing a spouted pouch according to claim 9, wherein the welding portion and the sealant layer in the non-sealed portion are welded together by heating to 150°C or higher.

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