Multilayer body for liquid packaging materials, and packaging material

Abstract

The present invention provides: a multilayer body which has excellent recyclability, aroma retention properties and heat seal strength, while being suitable for liquid packaging materials; and a liquid packaging material.　The present invention provides a multilayer body for liquid packaging materials, the multilayer body comprising a stretched polyethylene film, an ethylene-based heat seal layer that has a film thickness of 45 µm to 250 µm, a coat layer that is disposed between the stretched polyethylene film and the heat seal layer, and an adhesion layer that is disposed between the stretched polyethylene film and the ethylene-based heat seal layer, wherein: the coat layer is a cured coating film of a coating agent which contains a polyisocyanate and a polyester polyol that comprises a skeleton derived from an ortho-directing aromatic carboxylic acid; and the adhesive layer is a cured coating film of a coating agent which contains a polyisocyanate and a polyester polyol that comprises a skeleton derived from an ortho-directing aromatic carboxylic acid.

Description

Laminated bodies for liquid packaging materials, packaging materials

[0001] The present invention relates to a laminate having excellent aroma retention properties and suitable for use as a liquid packaging material, and to a packaging material using the laminate.

[0002] Packaging materials used for packaging food and daily necessities are usually laminated together with an adhesive between a heat-sealable film such as a polyethylene film or a polypropylene film and a resin film such as a polyester film or a nylon film, which has excellent heat resistance and strength (Patent Documents 1 and 2). Meanwhile, in recent years, with the growing demand for a recycling-oriented society, attempts have been made to recycle and reuse packaging materials. However, in laminates made by laminating different types of resin films, it is difficult to separate the resins into different types, making them unsuitable for recycling.

[0003] JP 2014-004799 A JP 2004-238050 A

[0004] A laminate for packaging with excellent recyclability could be one that uses a biaxially oriented polyolefin film such as oriented polypropylene or oriented polyethylene film on the outer layer side, as viewed from the contents, and an unoriented polypropylene film or low-density polyethylene film on the inner layer side (sealant film). Because olefin resin accounts for most of the entire laminate, such a laminate has excellent recyclability compared to laminates using different substrates. However, laminates bonded with low-polarity films such as olefin-based films have significantly inferior aroma retention compared to laminates using polar films such as PET film. This makes it unsuitable for packaging products containing fragrances, such as shampoo, conditioner, and dishwashing detergent.

[0005] Furthermore, when the laminate is made up almost entirely of olefin resin, the laminate has low heat resistance, making it impossible to heat seal at high temperatures and shortening the heat-sealing time. As a result, the heat-seal strength tends to be low, making it unsuitable for packaging liquid products such as shampoo, conditioner, and dishwashing detergent.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminate and a liquid packaging material which are excellent in recyclability, aroma retention and heat seal strength and are suitable for use as liquid packaging materials.

[0007] The present invention relates to a laminate for liquid packaging, which comprises a stretched polyethylene film, an ethylene-based heat-seal layer having a thickness of 45 μm to 250 μm, a coating layer disposed between the stretched polyethylene film and the heat-seal layer, and an adhesive layer disposed between the stretched polyethylene film and the ethylene-based heat-seal layer, wherein the coating layer is a cured coating film of a coating agent containing a polyester polyol having a skeleton derived from an ortho-oriented aromatic carboxylic acid and a polyisocyanate, and the adhesive layer is a cured coating film of a coating agent containing a polyester polyol having a skeleton derived from an ortho-oriented aromatic carboxylic acid and a polyisocyanate, and to a liquid packaging material obtained using the same.

[0008] According to the laminate of the present invention, a laminate and a packaging material that are recyclable and suitable for packaging liquid packaging materials can be obtained.

[0009] <Laminate> (Stretched Polyethylene Film) Examples of stretched polyolefin films include high density polyethylene film (HDPE), uniaxially stretched polyethylene film (MDOPE), and biaxially stretched polyethylene film (BOPE).

[0010] The stretched polyethylene film may contain additives as needed. Specifically, plastic compounding agents and additives such as lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments may be added to improve or modify processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, mold releasability, flame retardancy, mildew resistance, electrical properties, strength, etc. The amount of additive added is adjusted within a range that does not affect other properties.

[0011] The stretched polyethylene film may be subjected to a surface treatment, which can improve adhesion to adjacent layers. The method of surface treatment is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

[0012] The thickness of the stretched polyethylene film can be adjusted appropriately depending on the purpose, but from the viewpoint of the balance between mechanical strength and processability, it is preferably 7 μm to 300 μm, more preferably 15 μm to 100 μm.

[0013] (Ethylene-Based Heat-Seal Layer) The ethylene-based heat-seal layer is made of an ethylene-based resin and has heat-sealability, being melted by heat and fused to each other. Specific examples include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), and ethylene-propylene copolymers; ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); and ionomers of ethylene-acrylic acid copolymers and ionomers of ethylene-methacrylic acid copolymers, which may be used alone or in combination of two or more.

[0014] Among these, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), and ethylene-propylene copolymers are preferably used, with linear low-density polyethylene (LLDPE) and ethylene-propylene copolymers being particularly preferred, because they can easily ensure suitable heat-sealing properties even when thin, have high adhesion to other resin layers such as the first cyclic polyolefin resin layer described below, and easily improve film formation stability when co-extruded with the layer.

[0015] The LDPE may be a branched low-density polyethylene obtained by high-pressure radical polymerization, and is preferably a branched low-density polyethylene obtained by homopolymerizing ethylene by high-pressure radical polymerization.

[0016] LLDPE that can be preferably used is one that is obtained by copolymerizing ethylene monomer as the main component with an α-olefin such as butene-1, hexene-1, octene-1, or 4-methylpentene as a comonomer by low-pressure radical polymerization using a single-site catalyst. The comonomer content in LLDPE is preferably in the range of 0.5 to 20 mol%, and more preferably in the range of 1 to 18 mol%.

[0017] Examples of single-site catalysts include various single-site catalysts, such as metallocene catalyst systems that combine a metallocene compound of a transition metal of Group IV or V of the periodic table with an organoaluminum compound and / or an ionic compound. Single-site catalysts have uniform active sites, and therefore, compared with multi-site catalysts with non-uniform active sites, the molecular weight distribution of the resulting resin is sharper, resulting in less precipitation of low-molecular-weight components when formed into a film, and in a resin with excellent physical properties such as stable seal strength and excellent blocking resistance.

[0018] The density of ethylene resin is 0.880 to 0.970 g / cm ３ It is preferable that the density is within this range. If the density is within this range, the film has appropriate rigidity and is excellent in mechanical strength such as heat seal strength and pinhole resistance, and the film formability and extrusion suitability are improved. In addition, the melting point is generally preferably in the range of 60 to 130°C, and more preferably 70 to 120°C. If the melting point is within this range, the processing stability and co-extrusion processability with the first cyclic polyolefin resin layer described below are improved. Furthermore, since the film is flexible, the pinhole resistance is also good. In addition, the MFR (190°C, 21.18N) of the ethylene resin is preferably 2 to 20 g / 10 min, and more preferably 3 to 10 g / 10 min. If the MFR is within this range, the extrusion moldability of the film is improved.

[0019] The thickness of the ethylene-based heat-sealable layer is 45 μm or more and 250 μm or less. This allows for a laminate with excellent heat-seal strength and resistance to contents. The thickness of the ethylene-based heat-sealable layer is more preferably 60 μm or more and 70 μm or more, and 230 μm or less and 210 μm or less.

[0020] (Adhesive Layer) The adhesive layer is a cured coating film of a two-component curing adhesive, and is disposed between the stretched polyethylene film and the ethylene-based heat seal layer. The two-component curing adhesive used in the present invention contains a polyol composition (X1) containing a polyester polyol (A) and a polyisocyanate composition (Y1) containing a polyisocyanate (B).

[0021] The polyester polyol (A) is a reaction product of a monomer composition (A') containing a polycarboxylic acid and a polyhydric alcohol, and includes at least one of a polyester polyol (A1) obtained by polycondensation of a polycarboxylic acid including an ortho-oriented aromatic polycarboxylic acid with a polyhydric alcohol, a polyester polyol (A2) having an isocyanuric ring, and a polyester polyol (A3) having a polymerizable carbon-carbon double bond.

[0022] Examples of ortho-oriented polycarboxylic acids used in the synthesis of polyester polyol (A1) include orthophthalic acid or its acid anhydride, naphthalene 2,3-dicarboxylic acid or its acid anhydride, naphthalene 1,2-dicarboxylic acid or its acid anhydride, anthraquinone 2,3-dicarboxylic acid or its acid anhydride, and 2,3-anthracenecarboxylic acid or its acid anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring. Examples of such substituents include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

[0023] The polycarboxylic acid used in the synthesis of the polyester polyol (A1) may contain a polycarboxylic acid other than the ortho-orientated polycarboxylic acid. Examples of polycarboxylic acids other than ortho-oriented polycarboxylic acids include aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid; unsaturated bond-containing polycarboxylic acids such as maleic anhydride, maleic acid, and fumaric acid; alicyclic polycarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and anhydrides or ester-forming derivatives of these dicarboxylic acids, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and aromatic polycarboxylic acids such as ester-forming derivatives of these dihydroxycarboxylic acids, and the like, and these can be used alone or in combination. Of these, succinic acid, 1,3-cyclopentanedicarboxylic acid, isophthalic acid and acid anhydrides thereof are preferred.

[0024] When the polycarboxylic acid contains a polycarboxylic acid other than an ortho-oriented polycarboxylic acid, the proportion of the ortho-oriented polycarboxylic acid in the total amount of polycarboxylic acids is preferably 50 to 100% by mass.

[0025] The polyhydric alcohol used in the synthesis of polyester polyol (A1) preferably contains at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, and cyclohexanedimethanol, and more preferably contains at least one selected from ethylene glycol and glycerin. The amount of these polyhydric alcohols in the polyhydric alcohols used as raw materials for polyester polyol (A1) is preferably 20 mass% or more. The entire amount may be these polyhydric alcohols.

[0026] The polyhydric alcohol may be used in combination with polyhydric alcohols other than those mentioned above. Examples of the polyhydric alcohol include aliphatic diols such as 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol; trihydric or higher polyhydric alcohols such as tris(2-hydroxyethyl)isocyanurate, 1,2,4-butanetriol, pentaerythritol, and dipentaerythritol; hydroquinone, resorcinol, catechol, naphthalenediol, biphenol, bisphenol A, bisphenol F, and tetramethylbiphenol; ethylene oxide-extended products thereof; and aromatic polyhydric phenols such as hydrogenated alicyclic alcohols.

[0027] When the polyester polyol (A1) has three or more hydroxyl groups (referred to as polyester polyol (a1) for convenience), some of the hydroxyl groups may be modified with acid groups. Such polyester polyols are hereinafter also referred to as polyester polyol (A1'). The polyester polyol (A1') is obtained by reacting the polyester polyol (a1) with a polycarboxylic acid or its acid anhydride. The proportion of hydroxyl groups modified with the polycarboxylic acid is preferably ⅓ or less of the hydroxyl groups in the polyester polyol (a1). Examples of polycarboxylic acids used for modification include, but are not limited to, succinic anhydride, maleic acid, fumaric acid, 1,2-cyclohexanedicarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phthalic anhydride, 2,3-naphthalenedicarboxylic anhydride, trimellitic anhydride, oleic acid, and sorbic acid.

[0028] The polyester polyol (A2) can be obtained, for example, by reacting a triol having an isocyanuric ring with a polycarboxylic acid including an ortho-oriented aromatic polycarboxylic acid and a polyhydric alcohol. Examples of the triol having an isocyanuric ring include alkylene oxide adducts of isocyanuric acid such as 1,3,5-tris(2-hydroxyethyl)isocyanuric acid and 1,3,5-tris(2-hydroxypropyl)isocyanuric acid. The ortho-oriented aromatic polycarboxylic acid, polycarboxylic acid, and polyhydric alcohol can be the same as those used for the polyester polyol (A1).

[0029] As the triol compound having an isocyanuric ring, 1,3,5-tris(2-hydroxyethyl)isocyanuric acid or 1,3,5-tris(2-hydroxypropyl)isocyanuric acid is preferably used. As the ortho-oriented aromatic polycarboxylic acid, orthophthalic anhydride is preferably used. As the polyhydric alcohol, ethylene glycol is preferably used.

[0030] The proportion of the triol having an isocyanuric ring in the polyhydric alcohol that is the raw material for the polyester polyol (A2) is preferably 10% by mass or more, and although there is no particular upper limit, it is preferably 80% by mass or less from the viewpoint of coating suitability.

[0031] The polyester polyol (A3) can be obtained by using a component having a polymerizable carbon-carbon double bond as a polycarboxylic acid or a polyhydric alcohol.

[0032] Examples of polycarboxylic acids having a polymerizable carbon-carbon double bond include maleic anhydride, maleic acid, fumaric acid, 4-cyclohexene-1,2-dicarboxylic acid and its acid anhydride, and 3-methyl-4-cyclohexene-1,2-dicarboxylic acid and its acid anhydride. It is believed that the fewer the number of carbon atoms, the less flexible the molecular chain and the less oxygen permeates, so maleic anhydride, maleic acid, and fumaric acid are preferred. Examples of polyhydric alcohols having a polymerizable carbon-carbon double bond include 2-butene-1,4-diol.

[0033] In addition to the above, a polycarboxylic acid or a polyhydric alcohol having no polymerizable carbon-carbon double bond may be used in combination. Examples of such polycarboxylic acids and polyhydric alcohols that can be used include those similar to those used for the polyester polyols (A1) and (A2). The polycarboxylic acid is preferably at least one selected from the group consisting of succinic acid, 1,3-cyclopentanedicarboxylic acid, orthophthalic acid, orthophthalic acid anhydride, and isophthalic acid, and more preferably at least one of orthophthalic acid and its acid anhydride. The polyhydric alcohol is preferably at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol, and more preferably ethylene glycol.

[0034] The hydroxyl value of the polyester polyol (A) is preferably 1 mgKOH / g or more and 350 mgKOH / g or less. When the polyester polyol (A) has acid groups, the acid value is preferably 200 mgKOH / g or less. There is no particular restriction on the lower limit, but as an example, it is 0.5 mgKOH / g or more. It may be 0 mgKOH / g. The hydroxyl value of the polyester polyol (A) can be measured by the hydroxyl value measurement method described in JIS-K0070, and the acid value can be measured by the acid value measurement method described in JIS-K0070.

[0035] The number average molecular weight of the polyester polyol (A) is particularly preferably 300 to 5000, since a crosslinking density sufficient to achieve an excellent balance between adhesiveness and aroma retention can be obtained. The number average molecular weight is more preferably 350 to 3000. The number average molecular weight is calculated from the obtained hydroxyl value and the designed number of functional hydroxyl groups.

[0036] The glass transition temperature of the polyester polyol (A) is preferably −30° C. or higher and 80° C. or lower, more preferably 0° C. or higher and 60° C. or lower, and even more preferably 25° C. or higher and 60° C. or lower, in view of the balance between adhesion to the substrate and aroma retention.

[0037] The polyester polyol (A) may be a polyester polyurethane polyol obtained by urethane elongation of a polyester polyol through a reaction with a diisocyanate compound, resulting in a number average molecular weight of 1,000 to 15,000. The urethane-elongated polyester polyol contains components with molecular weights equal to or greater than a certain level and urethane bonds, and therefore has excellent initial cohesion and is an excellent adhesive for lamination.

[0038] The polyisocyanate composition (Y1) contains an isocyanate compound (B). The isocyanate compound (B) can be any known compound without any particular limitation, and examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, or trimers of these isocyanate compounds, and adducts obtained by reacting an excess amount of these isocyanate compounds with low-molecular-weight active hydrogen compounds such as ethylene glycol, propylene glycol, meta-xylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, and meta-xylylenediamine, and alkylene oxide adducts thereof, various polyester resins, polyether polyols, and polymeric active hydrogen compounds of polyamides. Alternatively, polyester polyisocyanates may be used which are obtained by reacting at least one of the polyester polyols (A1) to (A3) with a diisocyanate compound in an isocyanate excess ratio relative to the hydroxyl groups and isocyanate groups. These may be used alone or in combination of two or more.

[0039] In addition, blocked isocyanates may be used as the isocyanate compound. Examples of the isocyanate blocking agent include phenols such as phenol, thiophenol, methylthiophenol, ethylthiophenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol, oximes thereof such as acetoxime, methylethylketoxime, and cyclohexanone oxime, alcohols such as methanol, ethanol, propanol, and butanol, halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol, tertiary alcohols such as t-butanol and t-pentanol, and lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propylolactam. In addition, aromatic amines, imides, active methylene compounds such as acetylacetone, acetoacetic ester, and ethyl malonate, mercaptans, imines, ureas, diaryl compounds, and sodium bisulfite may also be used. The blocked isocyanate can be obtained by subjecting the above isocyanate compound to an addition reaction with an isocyanate blocking agent by a known, conventional, appropriate method.

[0040] Among these, it is more preferable to use isocyanate compounds having a skeleton derived from xylylene diisocyanate, hydrogenated xylylene diisocyanate, toluene diisocyanate, or diphenylmethane diisocyanate, as these compounds provide good aroma retention.

[0041] Examples of such isocyanate compounds include a diisocyanate trimer, a biuret compound synthesized by reaction with an amine, and an adduct compound formed by reaction with an alcohol. Compared to trimers and biuret compounds, adduct compounds have better solubility in organic solvents used in solvent-based adhesives, so they are preferably used when the adhesive is solvent-based. As the adduct compound, an adduct compound formed by reaction with an alcohol appropriately selected from the above-mentioned low-molecular-weight active hydrogen compounds can be used, but among them, adduct compounds with ethylene oxide adducts of trimethylolpropane, glycerol, triethanolamine, and metaxylenediamine are preferred.

[0042] Furthermore, when a composition containing a polyester polyol having residual carboxylic acid groups, such as polyester polyol (A1′), is used as the polyol composition (X1), the polyisocyanate composition (Y1) may contain an epoxy compound. Examples of the epoxy compound include diglycidyl ether of bisphenol A and its oligomer, diglycidyl ether of hydrogenated bisphenol A and its oligomer, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-oxybenzoic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, ethylene glycol diglycidyl ether, and propylene glycol diglycidyl. ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, triglycidyl ether of glycerol alkylene oxide adduct, and the like.

[0043] When an epoxy compound is used, a commonly known epoxy curing accelerator may be added as needed to accelerate curing, provided that the object of the present invention is not impaired.

[0044] The polyol composition (X1) and the polyisocyanate composition (Y1) are preferably blended so that the equivalent ratio of hydroxyl groups contained in the polyol composition (X1) to isocyanate groups contained in the polyisocyanate composition (Y1) is 1 / 0.5 to 1 / 10, and more preferably 1 / 1 to 1 / 5. If the isocyanate compound is in excess, the excess isocyanate compound remaining in the cured coating film of the adhesive may bleed out from the adhesive layer. On the other hand, if the reactive functional groups contained in the polyisocyanate composition (Y1) are insufficient, the adhesive strength may be insufficient.

[0045] The adhesive may contain various additives (C) within the range that does not impair the effects of the present invention. An inorganic filler (C1) may be used as such additive (C). Examples of the inorganic filler (C1) include silica, alumina, aluminum flakes, and glass flakes. The use of a plate-like inorganic compound as the inorganic filler (C1) is particularly preferred because it improves adhesive strength, aroma retention, light-blocking properties, and the like. Examples of plate-like inorganic compounds include hydrous silicates (such as phyllosilicate minerals), kaolinite-serpentine clay minerals (such as halloysite, kaolinite, endelite, dickite, nacrite, antigorite, chrysotile, etc.), pyrophyllite-talc (such as pyrophyllite, talc, keroli), smectite clay minerals (such as montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, stevensite, etc.), vermiculite clay minerals (such as vermiculite), mica or mica clay minerals (such as muscovite and phlogopite, margarite, tetrasilylic mica, taeniolite, etc.), chlorite (such as cucaite, sudoite, clinochlore, chamosite, nimite, etc.), hydrotalcite, plate-like barium sulfate, boehmite, and aluminum polyphosphate. These minerals may be natural or synthetic clay minerals. The plate-like inorganic compounds can be used alone or in combination of two or more.

[0046] The plate-like inorganic compound may be ionic, having an interlayer charge, or nonionic, having no charge. The presence or absence of an interlayer charge does not have a significant direct effect on the aroma retention of the adhesive layer. However, ionic plate-like inorganic compounds and inorganic compounds that swell in water are less dispersible in solvent-based adhesives, and increasing the amount added may cause the adhesive to thicken or become thixotropic, resulting in reduced coating suitability. For this reason, it is preferable that the plate-like inorganic compound be nonionic, having no interlayer charge.

[0047] The average particle size of the plate-like inorganic compound is not particularly limited, but is preferably 0.1 μm or more, and more preferably 1 μm or more. If it is smaller than 0.1 μm, the bypass path for oxygen molecules will not be long, and sufficient improvement in aroma retention cannot be expected. There is no particular upper limit to the average particle size, but if the particle size is too large, defects such as streaks may occur on the coated surface depending on the coating method. Therefore, as an example, the average particle size is preferably 100 μm or less, and preferably 20 μm or less. In this specification, the average particle size of the plate-like inorganic compound refers to the particle size that appears most frequently when the particle size distribution of the plate-like inorganic compound is measured using a light scattering measuring device.

[0048] The aspect ratio of the plate-like inorganic compound is preferably high in order to improve aroma retention due to the oxygen labyrinth effect, specifically, 3 or more, more preferably 10 or more, and most preferably 40 or more.

[0049] The amount of the plate-like inorganic compound to be blended is arbitrary. As an example, the amount of the plate-like inorganic compound to be blended is 5 to 50 parts by mass when the total mass of the solid contents of the polyol composition (X1), the polyisocyanate composition (Y1), and the plate-like inorganic compound is 100 parts by mass.

[0050] The adhesive may contain a coupling agent (C2). Examples of the coupling agent (C2) include a silane coupling agent, a titanate-based coupling agent, and an aluminum-based coupling agent.

[0051] Examples of the silane coupling agent include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane, γ-mercaptopropyltrimethoxysilane, and the like.

[0052] Examples of titanate coupling agents include tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxytitanium.

[0053] Examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate.

[0054] When the adhesive layer requires acid resistance, it may contain a known acid anhydride (C3). Examples of the acid anhydride (C3) include phthalic anhydride, succinic anhydride, HET anhydride, HIMIC anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydraphthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenotetracarboxylic anhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 5-(2,5-oxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, and styrene-maleic anhydride copolymer.

[0055] If necessary, a compound (C4) having an oxygen-scavenging function may be further added. Examples of the compound (C4) having an oxygen-scavenging function include low-molecular-weight organic compounds that react with oxygen, such as hindered phenols, vitamin C, vitamin E, organic phosphorus compounds, gallic acid, and pyrogallol, and transition metal compounds, such as cobalt, manganese, nickel, iron, and copper.

[0056] The curing reaction can be accelerated by using a catalyst (C5) as needed. The catalyst (C5) is not particularly limited as long as it accelerates the urethanization reaction of the polyol composition (X) and the polyisocyanate composition (Y), and examples thereof include metal catalysts, amine catalysts, aliphatic cyclic amide compounds, and titanium chelate complexes.

[0057] Examples of metal catalysts include metal complex catalysts, inorganic metal catalysts, and organic metal catalysts. Examples of metal complex catalysts include acetylacetonate salts of metals selected from the group consisting of Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), Th (thorium), Ti (titanium), Al (aluminum), and Co (cobalt), such as iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, and zirconia acetylacetonate. From the viewpoints of toxicity and catalytic activity, iron acetylacetonate (Fe(acac) ３ ) or manganese acetylacetonate (Mn(acac) ２ ) is preferred.

[0058] Examples of inorganic metal catalysts include those selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, and the like.

[0059] Examples of the organometallic catalyst include organic zinc compounds such as zinc octylate, zinc neodecanoate, and zinc naphthenate; organic tin compounds such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organic nickel compounds such as nickel octylate and nickel naphthenate; organic cobalt compounds such as cobalt octylate and cobalt naphthenate; organic bismuth compounds such as bismuth octylate, bismuth neodecanoate, and bismuth naphthenate; and titanium compounds such as tetraisopropyloxytitanate, dibutyltitanium dichloride, tetrabutyltitanate, and butoxytitanium trichloride.

[0060] Examples of the amine catalyst include triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N',N",N"-pentamethyldipropylenetriamine, N,N,N',N'-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N,N-dimethyl-N'-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N'-(2-hydroxyethyl)propanediamine, bis(dimethylaminopropyl)amine, bis(dimethylaminopropyl)isopropyl propanolamine, 3-quinuclidinol, N,N,N',N'-tetramethylguanidine, 1,3,5-tris(N,N-dimethylaminopropyl)hexahydro-S-triazine, 1,8-diazabicyclo[5.4.0]undecene-7, N-methyl-N'-(2-dimethylaminoethyl)piperazine, N,N'-dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1 , 2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N,N-dimethylhexanolamine, N-methyl-N'-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)imidazole, 1-(2-hydroxypropyl)imidazole, 1-(2-hydroxyethyl)-2-methylimidazole, 1-(2-hydroxypropyl)-2-methylimidazole, and the like.

[0061] Examples of the aliphatic cyclic amide compound include δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, β-propiolactam, etc. Among these, ε-caprolactam is more effective in accelerating curing.

[0062] The titanium chelate complex is a compound whose catalytic activity is enhanced by ultraviolet irradiation, and titanium chelate complexes having an aliphatic or aromatic diketone as a ligand are preferred because of their excellent curing-accelerating effect. In the present invention, those having an alcohol having 2 to 10 carbon atoms as a ligand in addition to an aromatic or aliphatic diketone are preferred because the effects of the present invention are more pronounced.

[0063] The catalyst (C5) may be used alone or in combination of two or more. The amount of the catalyst (C5) is preferably 0.001 to 3 parts by mass, and more preferably 0.01 to 2 parts by mass, per 100 parts by mass of the total solid content of the polyol composition (X) and the polyisocyanate composition (Y).

[0064] The adhesive may contain a phosphoric acid (C6). Specific examples of the phosphoric acid (C6) include phosphoric acid, pyrophosphoric acid, triphosphoric acid, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, dibutyl phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, isododecyl acid phosphate, butoxyethyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, and polyoxyethylene alkyl ether phosphate. The amount of the phosphoric acid (C6) blended is preferably 0.005 to 10% by mass, and more preferably 0.01 to 1% by mass, of the total solids content of the adhesive.

[0065] In addition, the adhesive may contain a stabilizer (antioxidant, heat stabilizer, ultraviolet absorber, etc.), a plasticizer, an antistatic agent, a lubricant, an antiblocking agent, a colorant, a crystal nucleating agent, etc. These various additives may be added in advance to either or both of the polyol composition (X1) and the polyisocyanate composition (Y1), or may be added when the polyol composition (X1) and the polyisocyanate composition (Y1) are mixed.

[0066] The adhesive used in the present invention may be either solvent-based or solventless. In this specification, the term "solvent-based adhesive" refers to a form used in a method in which the adhesive is applied to a substrate, heated in an oven or the like to volatilize the organic solvent in the coating film, and then laminated to another substrate, a so-called dry lamination method. Examples of solvents that can be used include toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluene, xylol, n-hexane, and cyclohexane. Either one or both of the polyol composition (X1) and the polyisocyanate composition (Y1) contain the organic solvent described above. In the case of a solvent-based adhesive, the solvent used as a reaction medium during the production of the components of the polyol composition (X1) or the polyisocyanate composition (Y1) may also be used as a diluent during coating.

[0067] A solventless adhesive is a form used in a method in which an adhesive is applied to a substrate and then bonded to another substrate without heating in an oven or the like to volatilize the solvent, a so-called non-solvent lamination method. Neither the polyol composition (X1) nor the polyisocyanate composition (Y1) contains substantially any of the organic solvents described above. If trace amounts of organic solvent remain in the polyol composition (X1) or polyisocyanate composition (Y1) due to incomplete removal of the constituent components of the polyol composition (X1) or polyisocyanate composition (Y1) or the organic solvent used as a reaction medium during the production of the raw materials, the polyol composition (X1) or polyisocyanate composition (Y1) is considered to be substantially free of organic solvent. Furthermore, if the polyol composition (X1) contains a low-molecular-weight alcohol, the low-molecular-weight alcohol reacts with the polyisocyanate composition (Y1) to become part of the coating film, and therefore does not need to be volatilized after application. Therefore, such a form is also considered a solventless adhesive.

[0068] When an olefin-based substrate is used, if the adhesive is solvent-based, the organic solvent tends to remain in the adhesive layer. If it is desired to reduce the amount of organic solvent remaining in the adhesive layer, a solventless adhesive can be selected.

[0069] Alternatively, when the adhesive used in the present invention is a solvent-based adhesive, it is preferable that the adhesive contains a drying aid (C7). This can prevent organic solvents from remaining in the adhesive layer. Examples of the drying aid (C7) include isosorbide, isomannide, isoidide, triacetin, etc., and isosorbide is preferably used. The amount of the drying aid (C7) can be adjusted as appropriate, but is, for example, 0.5% by mass or more and 50% by mass or less of the adhesive.

[0070] When the adhesive used in the present invention is a solventless type, it is preferable that the adhesive contains a reactive diluent (C8). This allows for a viscosity suitable for the non-solvent lamination method. Examples of the reactive diluent (C8) include isosorbide, isoidide, isomannide, furandiethanol, trans-tetrahydrofuran-3,4-diol, sorbitol, and erythritol, with isosorbide being preferred. The amount of reactive diluent (C8) can be adjusted as appropriate, but as an example, it is 5% by mass or more and 90% by mass or less, preferably 80% by mass or less, and more preferably 70% by mass or less of the total amount of polyester polyol (A) and reactive diluent (C8).

[0071] When the adhesive is solvent-based, the adhesive is applied to one substrate using a roll such as a gravure roll, and the organic solvent is evaporated by heating in an oven or the like, and then the other substrate is laminated to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably room temperature to 80°C, and the aging time is preferably 12 to 240 hours.

[0072] When the adhesive is a solventless type, the adhesive, which has been preheated to about 40°C to 100°C, is applied to one substrate using a roll such as a gravure roll, and the other substrate is immediately laminated to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

[0073] The amount of adhesive to be applied is adjusted as appropriate. In the case of a solvent-based adhesive, for example, the solid content is 1 g / m ２ 10g / m or more ２ Preferably 1 g / m or less２ 5g / m or more ２ In the case of a solvent-free type, the amount of adhesive applied is adjusted to, for example, 1 g / m ２ 10g / m or more ２ Preferably 1 g / m or less ２ 5g / m or more ２ The following is the result.

[0074] (Coating layer) The coating agent used to form the coating layer is a two-component curing coating agent containing a polyol composition (X2) containing a polyester polyol (D) and a polyisocyanate composition (Y2) containing an isocyanate compound (E). The coating layer is provided between the stretched polyethylene film and the ethylene-based heat seal layer.

[0075] As the polyester polyol (D), those having the same skeleton as the polyester polyols (A1) to (A3) (referred to as polyester polyols (D1), (D2), and (D3), respectively) can be used.

[0076] The hydroxyl value of the polyester polyol (D) is preferably 1 mgKOH / g or more and 350 mgKOH / g or less. When the polyester polyol (D) has an acid group, the acid value is preferably 200 mgKOH / g or less. There is no particular restriction on the lower limit, but, as an example, it is 0.5 mgKOH / g or more. It may even be 0 mgKOH / g.

[0077] The number average molecular weight of the polyester polyol (D) is particularly preferably 400 to 5000, since a crosslinking density sufficient to achieve an excellent balance between adhesion to the substrate and aroma retention can be obtained. The number average molecular weight is more preferably 500 to 2500. The number average molecular weight is calculated from the obtained hydroxyl value and the designed number of functional hydroxyl groups.

[0078] The glass transition temperature of the polyester polyol (D) is preferably 10°C or higher and 80°C or lower, more preferably 20°C or higher and 60°C or lower, and even more preferably 35°C or higher and 60°C or lower, in view of the balance between adhesion to the substrate and aroma retention.

[0079] The isocyanate compound (E) may be the same as the isocyanate compound (B). It is preferable to use an isocyanate having an aromatic ring or a derivative thereof (isocyanurate, allophanate, biuret, adduct, polyurethane polyisocyanate) (E1). Specific examples of the isocyanate compound (E1) include isocyanate compounds having a skeleton derived from xylylene diisocyanate, hydrogenated xylylene diisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

[0080] In view of the good aroma retention properties, it is also preferable that the isocyanate compound (E) is a polyurethane polyisocyanate (E2) obtained by reacting at least one selected from polyester polyols (D1), (D2), and (D3) with an isocyanate having an aromatic ring or a derivative thereof (E1) in such a ratio that the equivalent ratio of the isocyanate group to the hydroxyl group, [NCO] / [OH], is 1.5 to 5.0.

[0081] The coating agent used in the present invention may be solvent-based or solventless, but is preferably a solvent-based coating agent containing an organic solvent (F) capable of diluting (dissolving) the polyester polyol (D). Examples of organic solvents (F) include esters such as ethyl acetate, butyl acetate, and cellosolve acetate; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; dimethyl sulfoxide; and dimethyl sulfamide. The organic solvent used as a reaction medium during the production of the components of the polyol composition (X2) or polyisocyanate composition (Y2) may also be used as a diluent during coating. It is preferable to use at least one of esters and ketones.

[0082] When the coating agent used in the present invention is solvent-based, it may contain a drying aid (G). The drying aid (G) has the function of promoting the volatilization of the organic solvent (F). Examples of the drying aid (F) include isosorbide, isomannide, isoidide, triacetin, and trimethylolpropane. It is preferable to use at least one selected from isosorbide and trimethylolpropane. Generally, organic solvents tend to be less likely to volatilize from compositions containing polyester polyols and organic solvents. However, coating agents using the above-mentioned polyester polyols (D1) to (D3) in particular can form coating films with excellent gas barrier properties, but their excellent gas barrier properties tend to hinder the volatilization of the organic solvent. The inclusion of the drying aid (G) facilitates the volatilization of the organic solvent (F) during the drying process, resulting in excellent drying properties for the gas barrier coating agent and less residue of the organic solvent (F) in the cured coating film.

[0083] Furthermore, it is preferable that the drying aid (G) has a hydroxyl group. This allows it to react with the isocyanate compound (E) and be incorporated into the cured coating film, so that, unlike additives without functional groups, there is no risk of it migrating from the coating layer to other layers over time, and it has little effect on the physical properties of the coating layer over time. The drying process here refers to a process in which the polyol composition (X2) and the polyisocyanate composition (Y2) are mixed, applied to a substrate, and then passed through an oven to volatilize the organic solvent (F) contained in the coating film of the coating agent.

[0084] From the viewpoint of effectively suppressing the residue of the organic solvent (F), the amount of the drying aid (G) is preferably 0.5% by mass or more, more preferably 1% by mass or more, of the total solid content of the coating agent, and from the viewpoint of the blocking resistance of the coating agent, it is preferably 30% by mass or less, more preferably 10% by mass or less.

[0085] The coating agent used in the present invention may contain components other than those described above. These components may be contained in either or both of the polyol composition (X2) and the polyisocyanate composition (Y2), or may be prepared separately and mixed immediately before application of the coating agent. Examples of other components (H) include inorganic fillers (H1), antiskinning agents (H2), coupling agents (H3), catalysts (H4), and phosphoric acids (H5).

[0086] As the inorganic filler (H1), the same fillers as those exemplified as the inorganic filler (C1) can be used. From the viewpoint of the balance between the gas barrier property and the drying property of the organic solvent (F), the proportion of the inorganic filler (H1) relative to the total amount of solids of the polyol composition (X2) and the polyisocyanate composition (Y2) is preferably 0.001 to 50 mass%, more preferably 0.01 to 40 mass%.

[0087] As the anti-skinning agent (H2), an organic solvent having a higher boiling point than the organic solvent (F) and having a high solubility for the polyester polyol (D) is used. The inclusion of the anti-skinning agent (H2) makes it possible to prevent the surface of the coating layer from drying before the organic solvent (F) volatilizes from the inside of the coating film of the coating agent, thereby preventing the volatilization of the organic solvent (F) from being hindered.

[0088] Specific examples of the anti-skinning agent (H2) include propylene glycol monomethyl ether, ethyl cellosolve, propyl acetate, and butyl acetate.

[0089] From the viewpoint of the balance between the gas barrier property and the drying property of the organic solvent (F), the blending amount of the anti-skinning agent (H2) is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the total amount of the polyol composition (X2) and the polyisocyanate composition (Y2) excluding the anti-skinning agent (H2) (including volatile components such as the organic solvent (F)).

[0090] As the coupling agent (H3), the same ones as those exemplified as the coupling agent (C2) can be used.

[0091] The catalyst (H4) may be the same as those exemplified as the catalyst (C5), and may be used alone or in combination of two or more. The amount of catalyst (H4) added is preferably 0.001 to 3 parts by mass, and more preferably 0.01 to 2 parts by mass, per 100 parts by mass of the total solid content of the polyol composition (X2) and the polyisocyanate composition (Y2).

[0092] As the phosphoric acid (H5), the same phosphoric acid as exemplified as the phosphoric acid (C6) can be used. When the coating agent used in the present invention contains the phosphoric acid (H5), the blending amount thereof is preferably 1 ppm or more and 200 ppm or less of the total solid content of the coating agent.

[0093] In addition to the components described above, the coating agent used in the present invention may contain leveling agents, polymethyl methacrylate-based organic fine particles, antifoaming agents, anti-sagging agents, wetting and dispersing agents, viscosity modifiers, ultraviolet absorbers, metal deactivators, peroxide decomposers, flame retardants, reinforcing agents, plasticizers, lubricants, surface conditioners, rust inhibitors, fluorescent brighteners, inorganic heat absorbers, flame retardants, antistatic agents, dehydrating agents, known and commonly used thermoplastic elastomers, tackifiers, melamine resins, reactive elastomers, etc. The amounts of these additives added are appropriately adjusted within a range that does not impair the desired properties of the coating agent of the present invention.

[0094] The polyol composition (X2) and the polyisocyanate composition (Y2) are preferably used by adjusting the molar ratio ([NCO] / [OH]) of the isocyanate groups contained in the polyisocyanate composition (Y2) to the hydroxyl groups contained in the polyol composition (X2) to be 0.3 to 6.

[0095] The coating amount (solid content) of the coating layer can be adjusted as appropriate. For example, it is 1.0 g / m ２ 4.0g / m or more ２ The following is the result.

[0096] (Printed Layer) The laminate of the present invention may be provided with a printed layer. The printed layer is a layer on which characters, figures, symbols, other desired designs, etc. are printed using liquid ink. In this specification, liquid ink is a general term for solvent-based inks used in gravure printing or flexographic printing. The liquid ink may contain a resin, a colorant, and a solvent as essential components, or may be a so-called clear ink that contains a resin and a solvent but is substantially free of a colorant. The printed layer is provided, for example, on either side of the stretched polyethylene film, directly or via a layer such as a primer layer that is receptive to liquid ink. The printed layer may be provided on the entire surface of the stretched polyolefin film, or on only a portion of the surface.

[0097] The resin used in the liquid ink is not particularly limited and may include, for example, acrylic resin, polyester resin, styrene resin, styrene-maleic acid resin, maleic acid resin, polyamide resin, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyvinyl chloride resin, chlorinated polypropylene resin, cellulose-based resin, epoxy resin, alkyd resin, rosin-based resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, etc., and one or more of these may be used in combination. Preferably, at least one or two or more selected from polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, and cellulose-based resin are used.

[0098] Colorants used in liquid inks include inorganic pigments such as titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine, carbon black, and graphite; organic pigments such as soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments; and extender pigments such as calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, and talc.

[0099] The organic solvent used in the liquid ink preferably does not contain an aromatic hydrocarbon organic solvent. More specific examples include alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol, ketone organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester organic solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, aliphatic hydrocarbon organic solvents such as n-hexane, n-heptane, and n-octane, and alicyclic hydrocarbon organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane, and these can be used alone or in combination of two or more.

[0100] (Heat-resistant coating layer) The laminate of the present invention preferably comprises a heat-resistant coating layer. The heat-resistant coating layer is provided on the stretched polyethylene film directly or via a printed layer. When the laminate of the present invention is made into a bag, the heat-resistant coating layer is the outermost layer as viewed from the contents, i.e., located on the side opposite to the side of the stretched polyethylene film on which the coating layer is applied, and is the layer that comes into contact with the heat seal bar during bag formation. It is also preferable that the stretched polyethylene film has heat-resistant coating layers on both sides.

[0101] The heat-resistant coating layer is formed by applying a heat-resistant coating agent to the stretched polyethylene film. Examples of the heat-resistant coating agent include those containing a compound having a cellulose skeleton, a benzene ring skeleton, an isocyanuric ring skeleton, or an alicyclic skeleton, whose homopolymer glass transition temperature (hereinafter sometimes referred to as Tg) is 100° C. or higher. Specific examples include cellulose derivatives such as nitrocellulose, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate; polyester resins having a benzene ring derived from phthalic acid, naphthalenedicarboxylic acid, and ethylene oxide (hereinafter sometimes referred to as EO) adducts of bisphenol A, and / or an alicyclic skeleton derived from cyclopentanediol, dimethyloltricyclodecane, and the like; aromatic isocyanates such as diphenylmethane diisocyanate, toluene diisocyanate, xylene diisocyanate, and naphthalenediisocyanate; alicyclic isocyanates such as isocyanuric triisocyanate and norbornene diisocyanate; and / or urethane resins made from isocyanuric triisocyanate and polyols and / or tris(2-hydroxyethyl)isocyanurate; Examples of the coating agent include a coating agent containing a compound having a benzene ring and an unsaturated double bond, such as phenoxydiethylene glycol acrylate, and / or a compound having an alicyclic structure and an unsaturated double bond, such as isobornyl acrylate or dicyclopentanyl acrylate, and a radical copolymer such as (meth)acrylate; and a two-component curing coating agent that uses as a curing agent at least one selected from aromatic isocyanates such as diphenylmethane diisocyanate, toluene diisocyanate, xylene diisocyanate or naphthalene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate or norbornene diisocyanate, derivatives of these isocyanates, and isocyanuric triisocyanate, and is based on a composition containing a resin having a functional group reactive with an isocyanate group, such as a hydroxyl group, an amino group, or a carboxyl group.

[0102] The heat-resistant coating agent may further contain a resin having a low Tg in consideration of adhesion to the stretched polyethylene film. The total amount of the cellulose skeleton, benzene ring skeleton, isocyanuric ring skeleton, and alicyclic skeleton is preferably 20 to 90 mass %, more preferably 30 to 80 mass %, of the solid content of the heat-resistant coating agent.

[0103] The heat-resistant coating agent preferably contains inorganic particles such as alumina, magnesia, titania, zirconia, and silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, ultrafine amorphous silica, etc.) as aggregates. This allows for the formation of a coating layer with superior heat resistance. Alternatively, the heat-resistant coating agent preferably contains particles of compounds with excellent thermal conductivity, such as boron nitride, aluminum nitride, alumina oxide, titanium oxide, magnesium oxide, zinc oxide, and silicon oxide. The inorganic particles may be used alone or in combination. The shape of the silica particles is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or amorphous silica particles may be used. For example, commercially available hollow silica microparticles such as Silinax manufactured by Nittetsu Mining Co., Ltd. may be used.

[0104] The primary particle diameter of the inorganic particles is preferably in the range of 5 to 200 nm. If the diameter is 5 nm or more, the inorganic fine particles in the dispersion are well dispersed, and if the diameter is 200 nm or less, the strength of the cured product is good. It is more preferably 10 nm to 100 nm. The amount of inorganic particles to be blended can be adjusted as appropriate, but as an example, it is 5 to 90 wt % of the total solid content of the heat-resistant coating agent containing the inorganic particles, and preferably 20 mass % or more.

[0105] The heat-resistant coating agent may contain wax, silicon additives, organic beads, etc. for the purposes of preventing scratches on the coated film, preventing blocking during laminate formation, imparting processability during bag making after the laminate has been produced, etc. Specific examples include waxes such as amide wax, polypropylene wax, polyethylene wax, paraffin wax, carnauba wax, rice wax, ethylene oxide (EO) adducts of dimethylsiloxane, silicon additives of modified silicon, and organic beads made of acrylic, nylon, urethane, or epoxy.

[0106] The heat-resistant coating agent is prepared by dissolving or dispersing these components in a solvent, such as water, aromatic hydrocarbon organic solvents such as toluene, xylene, Solvesso #100, and Solvesso #150, aliphatic hydrocarbon organic solvents such as hexane, methylcyclohexane, heptane, octane, and decane, and various ester organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate. Examples of water-miscible organic solvents include alcohols such as methanol, ethanol, propanol, butanol, and isopropyl alcohol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; and glycol ethers such as ethylene glycol (mono- and di-)methyl ether, ethylene glycol (mono- and di-)ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono- and di-)methyl ether, diethylene glycol (mono- and di-)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono- and di-)methyl ether, propylene glycol (mono- and di-)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono- and di-)methyl ether. These can be used alone or in combination of two or more. Furthermore, to more effectively carry out coating, an antifoaming agent or a leveling agent can be used.

[0107] (Other Layers) The laminate of the present invention may include layers other than those described above. For example, as a layer having gas barrier properties, it may include an inorganic vapor deposition layer or a coating layer having gas barrier properties. The inorganic vapor deposition layer is a layer having gas barrier properties that prevents the permeation of oxygen gas and water vapor gas, and is a vapor deposition layer made of an inorganic substance or an inorganic oxide. Examples of inorganic substances or inorganic oxides include aluminum, alumina, silica, etc., which may be used alone or in combination of two or more types, such as in binary vapor deposition of silica and alumina. Two or more inorganic vapor deposition layers may be provided. When two or more inorganic vapor deposition layers are provided, they may have the same composition or different compositions.

[0108] The inorganic vapor deposition layer can be formed on the resin layer by a conventionally known method, for example, physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0109] The inorganic vapor-deposited layer may have a thickness of, for example, 1 to 200 nm. When the inorganic vapor-deposited layer is an aluminum vapor-deposited layer, the thickness thereof is, for example, 1 to 100 nm. When the inorganic vapor-deposited layer is a silica or alumina vapor-deposited layer, the thickness thereof is, for example, 1 to 100 nm.

[0110] The coating layer having gas barrier properties is formed by applying and drying a coating agent containing, for example, a polyvinyl gas barrier resin. Conventional coating agents can be used as such coating agents, and examples include those containing a vinyl alcohol polymer such as polyvinyl alcohol, ethylene vinyl alcohol, or polyvinyl butyral, and an aqueous solvent. The vinyl alcohol polymer may have a reactive functional group other than a hydroxyl group, such as an acetoacetyl group, a carboxyl group, an anionic carboxyl group, a sulfonic acid group, or an anionic sulfonic acid group. These may be used alone or in combination of two or more.

[0111] Examples of aqueous solvents include water, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; diols such as butanediol, pentanediol, and hexanediol; glycol esters such as propylene glycol laurate; diethylene glycol ethers such as diethylene glycol monoethyl, diethylene glycol monobutyl, diethylene glycol monohexyl, and carbitol; glycol ethers such as propylene glycol ether, dipropylene glycol ether, and cellosolve containing triethylene glycol ether; alcohols such as methanol, ethanol, isopropyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, butyl alcohol, and pentyl alcohol; lactones such as sulfolane, esters, ketones, and γ-butyrolactone; lactams such as N-(2-hydroxyethyl)pyrrolidone; and glycerin and its polyalkylene oxide adducts. The aqueous solvents can be used alone or in combination of two or more.

[0112] The coating agent may further contain a layered inorganic compound, a crosslinking agent capable of reacting with a functional group possessed by the vinyl alcohol polymer, an inorganic filler, an antifoaming agent, a stabilizer (antioxidant, heat stabilizer, ultraviolet absorber, etc.), a plasticizer, an antistatic agent, a lubricant, an antiblocking agent, a colorant, a leveling agent, etc.

[0113] Commercially available coating agents can be used to form a coating layer having gas barrier properties, and examples include EXEVIA (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., the SunBar (registered trademark) series manufactured by Sun Chemical Co., Ltd., and the Takelac WPB (registered trademark) series manufactured by Mitsui Chemicals, Inc.

[0114] However, laminates including an inorganic vapor deposition layer or a coating layer with gas barrier properties often have sufficient aroma retention due to their effects, and therefore the present invention is preferably applied to laminates that do not include an inorganic vapor deposition layer or a coating layer with gas barrier properties.

[0115] Similarly, laminates containing a film made of polyester resin, for example, often have sufficient aroma retention by themselves, and therefore the present invention is preferably applied to laminates that do not contain such substrates.

[0116] It is also preferable that the film further contains a stretched polyethylene film. In this case, the stretched polyethylene film used can be the same as those described above.

[0117] Suitable examples of the laminate of the present invention include: (1) Stretched polyethylene film / coating layer / printing layer / adhesive layer / ethylene-based heat-sealing layer; (2) Stretched polyethylene film / printing layer / coating layer / adhesive layer / ethylene-based heat-sealing layer; (3) Stretched polyethylene film / coating layer / adhesive layer / ethylene-based heat-sealing layer; (4) Heat-resistant coating layer / stretched polyethylene film / coating layer / printing layer / adhesive layer / ethylene-based heat-sealing layer; (5) Heat-resistant coating layer / stretched polyethylene film / printing layer / coating layer / adhesive layer / ethylene-based heat-sealing layer; (6) Heat-resistant coating layer / stretched polyethylene film / coating layer / adhesive layer / ethylene-based heat-sealing layer.

[0118] (7) Stretched polyethylene film / coating layer / printing layer / adhesive layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (8) Stretched polyethylene film / printing layer / coating layer / adhesive layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (9) Stretched polyethylene film / printing layer / adhesive layer / stretched polyethylene film / coating layer / adhesive layer / ethylene-based heat-sealing layer (10) Stretched polyethylene film / printing layer / adhesive layer / coating layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (11) Stretched polyethylene film / coating layer / adhesive layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (12) Stretched polyethylene film / adhesive layer / coating layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (13) Stretched polyethylene film / adhesive layer / stretched polyethylene film / coating layer / adhesive layer / ethylene-based heat-sealing layer

[0119] (14) heat-resistant coating layer / stretched polyethylene film / coating layer / printing layer / adhesive layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (15) heat-resistant coating layer / stretched polyethylene film / printing layer / coating layer / adhesive layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (16) heat-resistant coating layer / stretched polyethylene film / printing layer / adhesive layer / stretched polyethylene film / coating layer / adhesive layer / ethylene-based heat-sealing layer (17) heat-resistant coating layer / stretched polyethylene film / printing layer / adhesive layer / coating layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (18) heat-resistant coating layer / stretched polyethylene film / coating layer / adhesive layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (19) heat-resistant coating layer / stretched polyethylene film / adhesive layer / coating layer / stretched polyethylene film / adhesive layer / ethylene-based heat-sealing layer (20) Heat-resistant coating layer / stretched polyethylene film / adhesive layer / stretched polyethylene film / coating layer / adhesive layer / ethylene-based heat-sealing layer, etc., but are not limited thereto. As the stretched polyethylene film, it is preferable to use an MDOPE film or a BOPE film.

[0120] When two adhesive layers are provided, as in the above-mentioned configuration examples (7) to (20), at least one of them may be the above-mentioned adhesive layer, and it is preferable that both layers be the above-mentioned adhesive layer. When two layers of stretched polyethylene film are included, as in the above-mentioned configuration examples (7) to (20), these may be different types of film or the same type of film. Furthermore, the thicknesses may be approximately the same (meaning that the difference in thickness is within 5 μm, although there may be differences within the range of manufacturing tolerance. Hereinafter, "approximately the same film or layer thickness" means the same thing), or they may be different. It is preferable that the thicknesses of the two layers of stretched polyethylene film are the same, or that the stretched polyethylene film located on the outer side from the contents when the bag is made is thicker. It is preferable that the difference in thickness between the two layers of stretched polyethylene film is 20 μm or less. When two layers of stretched polyethylene film are included as in the above structural examples (7) to (20), it is preferable that the coating layer is provided on the stretched polyethylene film closer to the ethylene-based heat seal layer as in structural examples (9), (10), (12), (13), (16), (17), (19), and (20).

[0121] <Packaging Materials> The laminate of the present invention can be used as packaging for liquid products such as liquid soap (hand soap), body soap, shampoo, rinse, conditioner, dishwashing detergent, liquid laundry detergent, fabric softener, sodium bicarbonate electrolyzed water, liquid bath additives, body milk, and other liquid products. The form of such packaging is not particularly limited, but one example is a so-called standing pouch, which is a self-standing square pouch formed by overlapping a front member and a back member and heat-sealing the left and right side edges to form a side seal, and folding in a bottom member and heat-sealing the outer periphery to form a bottom seal. At least one of the left and right side edges of the packaging material may have a notch to facilitate opening the packaging material, and may also be half-cut. Furthermore, a means for facilitating pouring of the contents may be provided at one of the top corners of the packaging material. Such means include a method of heat-sealing the front and back members together to create a tapered spout that faces diagonally outward and upward, or a method of joining a spout that has been formed separately by molding.

[0122] Among the components constituting the packaging material of the present invention, all components made of a laminate are manufactured from the laminate of the present invention. However, the components may all be laminates of the same configuration, or they may be different. For example, in a first embodiment of the packaging material of the present invention, the front and back members are selected from the laminate configuration examples (1), (2), (4), and (5) described above, and the bottom member is selected from the laminate configuration examples (3) and (6). In the first embodiment, the thicknesses of the stretched polyethylene films in the front and back members are approximately the same. The thickness of the stretched polyethylene film in the bottom member may be approximately the same as, or may be thinner or thicker than, the thickness of the stretched polyethylene film in the front and back members. The difference between the thickness of the stretched polyethylene film in the bottom member and the thickness of the stretched polyethylene film in the front and back members is within 20 μm.

[0123] In the first embodiment, the thickness of the ethylene-based heat-sealable layer in the front member and the back member is approximately the same. The thickness of the ethylene-based heat-sealable layer in the bottom member may be approximately the same as, or may be thinner or thicker than, the thickness of the heat-sealable layer in the front member and the back member. The difference between the thickness of the ethylene-based heat-sealable layer in the bottom member and the thickness of the ethylene-based heat-sealable layer in the front member and the back member is within 30 μm.

[0124] In a second embodiment of the packaging material of the present invention, the front member, back member, and bottom member are all selected from the laminate configuration examples (1), (2), (4), and (5) described above, and may all be laminates of the same configuration example or may be different. In the second embodiment, the thickness of the stretched polyethylene film in the front member and back member is approximately the same. The thickness of the stretched polyethylene film in the bottom member may be approximately the same as the thickness of the stretched polyethylene film in the front member and back member, or may be thinner or thicker. The difference between the thickness of the stretched polyethylene film in the bottom member and the thickness of the stretched polyethylene film in the front member and back member is within 20 μm.

[0125] In the second embodiment, the thickness of the ethylene-based heat-sealable layer in the front member and the back member is approximately the same. The thickness of the ethylene-based heat-sealable layer in the bottom member may be approximately the same as, or may be thinner or thicker than, the thickness of the heat-sealable layer in the front member and the back member. The difference between the thickness of the ethylene-based heat-sealable layer in the bottom member and the thickness of the ethylene-based heat-sealable layer in the front member and the back member is within 30 μm.

[0126] In a third embodiment of the packaging material of the present invention, the front member, back member, and bottom member are all selected from the laminate configuration examples (3) and (6) described above. They may all be made of laminates of the same configuration example, or they may be different. In the third embodiment, the thickness of the stretched polyethylene film in the front member and back member is approximately the same. The thickness of the stretched polyethylene film in the bottom member may be approximately the same as, or may be thinner or thicker than, the thickness of the stretched polyethylene film in the front member and back member. The difference between the thickness of the stretched polyethylene film in the bottom member and the thickness of the stretched polyethylene film in the front member and back member is within 20 μm.

[0127] In a third embodiment, the thickness of the ethylene-based heat-sealable layer in the front member and the back member is approximately the same. The thickness of the ethylene-based heat-sealable layer in the bottom member may be approximately the same as, or may be thinner or thicker than, the thickness of the heat-sealable layer in the front member and the back member. The difference between the thickness of the ethylene-based heat-sealable layer in the bottom member and the thickness of the ethylene-based heat-sealable layer in the front member and the back member is within 30 μm.

[0128] In a fourth embodiment of the packaging material of the present invention, the front and back members are selected from the laminate configuration examples (7) to (20) described above, and the bottom member is selected from the laminate configuration examples (1) to (6). In the fourth embodiment, the front and back members are preferably made of the same laminate configuration example.

[0129] In a fourth embodiment, the thickness of the ethylene-based heat-sealable layer on the front member and the back member is approximately the same. The thickness of the ethylene-based heat-sealable layer on the bottom member may be approximately the same as, or may be thinner or thicker than, the thickness of the heat-sealable layer on the front member and the back member. The difference between the thickness of the ethylene-based heat-sealable layer on the bottom member and the thickness of the ethylene-based heat-sealable layer on the front member and the back member is within 50 μm.

[0130] In a fifth embodiment of the packaging material of the present invention, the front member, rear member, and bottom member are all selected from the laminate configuration examples (7) to (20) described above. They may all be made of laminates of the same configuration example, or they may all be different. In the fifth embodiment, it is preferable that the front member and the rear member are made of laminates of the same configuration example.

[0131] In a fifth embodiment, the thickness of the ethylene-based heat-sealable layer on the front member and the back member is approximately the same. The thickness of the ethylene-based heat-sealable layer on the bottom member may be approximately the same as, or may be thinner or thicker than, the thickness of the heat-sealable layer on the front member and the back member. The difference between the thickness of the ethylene-based heat-sealable layer on the bottom member and the thickness of the ethylene-based heat-sealable layer on the front member and the back member is within 50 μm.

[0132] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, the blending compositions and other numerical values ​​are based on mass.

[0133] <Adhesive Preparation> (Adhesive 1) (Polyol Composition (X1-1)) A polyester reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, and a condenser was charged with 79.10 parts of ethylene glycol, 74.06 parts of phthalic anhydride, 73.07 parts of adipic acid, and 0.01 parts of titanium tetraisopropoxide, and gradually heated so that the temperature at the top of the distillation tube did not exceed 100 ° C. The internal temperature was maintained at 220 ° C. The esterification reaction was terminated when the acid value reached 1 mg KOH / g or less, and 0.03 parts of phosphoric acid was added while further heating to 60 ° C. and stirred for 1 hour to obtain a polyester polyol having a number average molecular weight of 800. The hydroxyl value was 143.2 mg KOH / g. The obtained polyester polyol was used as polyol composition (X1-1).

[0134] (Polyisocyanate Composition (Y1-1)) A polyester reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, and a condenser was charged with 79.27 parts of ethylene glycol, 59.25 parts of phthalic anhydride, 87.68 parts of adipic acid, and 0.02 parts of titanium tetraisopropoxide, and the mixture was gradually heated so that the temperature at the top of the distillation tube did not exceed 100° C., and the internal temperature was maintained at 220° C. When the acid value reached 1 mgKOH / g or less, the esterification reaction was terminated, and 0.06 parts of phosphoric acid was added while further heating to 60° C., and the mixture was stirred for 1 hour, yielding a polyester intermediate (y1-1) having a number average molecular weight of 850.

[0135] A reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, a cooling condenser, and a dropping funnel was charged with 69.06 parts of xylylene diisocyanate and 30.61 parts of Millionate MN (a mixture of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate), and the mixture was stirred while heating to 70°C. 100.33 parts of polyester intermediate (y1-1) was added dropwise using the dropping funnel over 2 hours, and the mixture was further stirred for 4 hours to obtain polyisocyanate composition (Y1-1). The NCO% measured in accordance with JIS-K1603 was 15.4%.

[0136] An adhesive 1 was obtained by mixing 60 parts of the polyol composition (X1-1) and 100 parts of the polyisocyanate composition (Y1-1).

[0137] (Adhesive 2) (Polyol Composition (X1-2)) A polyester reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, and a condenser was charged with 20.98 parts of ethylene glycol, 0.12 parts of glycerin, 50.94 parts of 1,3,5-tris(2-hydroxyethyl)isocyanuric acid, and 50.41 parts of phthalic anhydride, and the mixture was gradually heated so that the temperature at the top of the distillation tube did not exceed 100°C, and the internal temperature was maintained at 220°C. When the acid value reached 1 mgKOH / g or less, the esterification reaction was terminated, yielding a polyester polyol having a number average molecular weight of 670. The hydroxyl value was 230.2 mgKOH / g. The resulting polyester polyol was used as polyol composition (X1-2).

[0138] (Polyisocyanate Composition (Y1-2)) A polyester reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, and a condenser was charged with 51.06 parts of ethylene glycol and 63.30 parts of phthalic anhydride, and the mixture was gradually heated so that the temperature at the top of the distillation tube did not exceed 100°C, and the internal temperature was maintained at 220°C. When the acid value reached 1 mgKOH / g or less, the esterification reaction was terminated, and 0.01 parts of phosphoric acid was added to obtain a polyester intermediate (y1-2) having a number average molecular weight of 340. The hydroxyl value was 331.0 mgKOH / g.

[0139] 125.00 parts of xylylene diisocyanate was placed in a reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, a cooling condenser, and a dropping funnel, and the mixture was stirred while heated to 70°C, to which 82.00 parts of polyester intermediate (y1-2) was added dropwise using the dropping funnel over 2 hours, followed by stirring for a further 4 hours to obtain an isocyanate compound (Y1-2). The NCO% measured in accordance with JIS-K1603 was 16.6%.

[0140] 100 parts of the polyol composition (X1-2) and 32 parts by mass of the polyisocyanate composition (Y1-2) were mixed and diluted with ethyl acetate to a solids content of 53%, thereby obtaining adhesive 2.

[0141] (Adhesive 3) (Polyol composition (X1')) A reactor equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, a cooling condenser, and a dropping funnel was charged with 73.98 parts of castor oil and 51.02 parts of polypropylene glycol (molecular weight approximately 4000), and the mixture was stirred while heating to 70 ° C. Millionate MN (a mixture of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate) was added dropwise using the dropping funnel, and the mixture was further stirred for 4 hours to obtain a polyol composition (X1'). The hydroxyl value was 115.0 mg KOH / g.

[0142] (Polyisocyanate composition (Y1')) 114.00 parts of Millionate MN (a mixture of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate) was placed in a reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, a cooling condenser, and a dropping funnel, and the mixture was stirred while heated to 70°C. 28.16 parts of polypropylene glycol (molecular weight: approximately 400) and 58.44 parts of polypropylene glycol (molecular weight: approximately 1000) were added dropwise using the dropping funnel over 2 hours, and the mixture was further stirred for 4 hours to obtain polyisocyanate composition (Y1'). The NCO% measured in accordance with JIS-K1603 was 13.5%.

[0143] An adhesive 3 was obtained by mixing 50 parts of the polyol composition (X1') and 100 parts of the polyisocyanate composition (Y1').

[0144] <Preparation of Coating Agent> (Synthesis of Polyester Polyol (D)) 1.26 parts of ethylene glycol, 26.76 parts of glycerin, and 40.99 parts of phthalic anhydride were charged into a polyester reaction vessel equipped with a stirrer, a nitrogen gas inlet tube, a Snyder tube, and a condenser, and the mixture was gradually heated so that the temperature at the top of the rectifying tube did not exceed 100°C, and the internal temperature was maintained at 190°C. When the acid value reached 40 mgKOH / g, 7.33 parts of phthalic anhydride was added, and when the acid value reached 70 mgKOH / g, the esterification reaction was terminated. A polyester polyol (D) with a number average molecular weight of 900 was obtained. The hydroxyl value was 165 mgKOH / g.

[0145] (Preparation of Coating Agent) A coating agent was prepared using 10 parts by mass of polyester polyol (D), 4.3 parts by mass of isosorbide, 16.0 parts of BARRISURF HX (manufactured by IMERYS, kaolin / non-swelling, interlayer nonionic, plate-like, average particle size / 1.5 μm, aspect ratio / approximately 100), 15.0 parts of XDI-TMP adduct, 23.0 parts of ethyl acetate, 23.0 parts of methyl ethyl ketone, and 1.0 part of propylene glycol monomethyl ether.

[0146] <Production of Laminate> (Example 1) A coating agent was applied to a BOPE film having a thickness of 40 μm so that the thickness of the dried coating film was 2.0 g / m ２The adhesive 1 was applied using a bar coater in a coating amount of 2.5 g / m. ２ (solid content), and the resulting mixture was laminated with an LLDPE film having a thickness of 60 μm, followed by aging at 40° C. for 3 days to obtain a laminate of Example 1.

[0147] (Example 2) A coating agent was applied to a BOPE film having a thickness of 40 μm so that the thickness of the dried coating film was 2.0 g / m ２ The adhesive 2 was applied using a bar coater in a coating amount of 3.5 g / m. ２ (solid content), which was then laminated to a 60 μm-thick LLDPE film, and aging was carried out at 40° C. for 4 days to obtain a laminate of Example 1.

[0148] (Comparative Example 1) A laminate of Comparative Example 1 was obtained in the same manner as in Example 1, except that adhesive 3 was used instead of adhesive 1. (Comparative Example 2) A laminate of Comparative Example 2 was obtained in the same manner as in Example 1, except that the formation of the coating layer was omitted. (Comparative Example 3) A laminate of Comparative Example 3 was obtained in the same manner as in Comparative Example 2, except that adhesive 3 was used instead of adhesive 1. (Comparative Example 4) A laminate of Comparative Example 4 was obtained in the same manner as in Example 2, except that adhesive 3 was used instead of adhesive 2.

[0149] <Evaluation> (Oxygen permeability) The obtained laminate was cut into a size of 10 cm x 10 cm, and the oxygen permeability was measured in accordance with JIS-K7126 (constant pressure method) using an OX-TRAN2 / 21 (oxygen permeability measuring device manufactured by Mocon Co., Ltd.) under atmospheres of 23°C, 0% RH and 90% RH. RH represents humidity.

[0150] (Oxygen Permeability - After Acceleration) The obtained laminate was cut into a 12 cm x 30 cm piece. The long side of the film was folded in half, and two sides were heat-sealed at 180°C, 0.1 MPa, and 1 second. 5 g of contents were then placed inside, and the remaining side was heat-sealed under the same conditions to create a three-sided seal. A PET film was placed between the laminate and the heat seal bar to prevent direct contact between the laminate and the heat seal bar. The bag was left at 50°C for 4 weeks, then opened and the contents were wiped off. A 10 cm x 10 cm measurement sample was cut from this, and the oxygen permeability was measured in the same manner as above. The contents used were Attack Antibacterial EX Super Clear Gel (Kao Corporation) and Merit Shampoo-DE1 (Kao Corporation).

[0151] (Lamination Strength) Using a tensile tester in an atmosphere of 25° C., the peeling speed was set to 300 mm / min, and the adhesive strength (N / 15 mm) between the BOPE film and the LLDPE film was measured by a T-type peeling method.

[0152] (Laminate Strength - After Acceleration) The resulting laminate was cut into a 12 cm x 30 cm piece. The long side of the film was folded in half, and two sides were heat-sealed at 180°C, 0.1 MPa, and 1 second. 5 g of contents were then placed inside, and the remaining side was heat-sealed under the same conditions to create a three-sided seal. A PET film was placed between the laminate and the heat seal bar to prevent direct contact between the laminate and the heat seal bar. The bag was left at 50°C for 4 weeks, then opened and the contents were wiped off. A 15 mm wide measurement sample was cut from this, and the laminate strength was measured in the same manner as above. The contents used were Attack Antibacterial EX Super Clear Gel (Kao Corporation) and Merit Shampoo-DE1 (Kao Corporation).

[0153] (Heat Seal Strength) The laminates produced in the Examples and Comparative Examples were cut into 10 cm x 10 cm pieces, and the LLDPE films were placed facing each other. Using a heat sealer, the LLDPE films were heat-sealed at 180°C, 0.1 MPa, and 1 second. A PET film was interposed between the laminate and the heat seal bar to prevent direct contact between the laminate and the heat seal bar. A 15 mm-wide sample was cut from each piece, and both ends were fixed to a tensile tester and measured in tensile mode (tensile speed: 300 mm / min). Five measurements were performed under the same conditions, and the average was used as the heat seal strength. The unit is N / 15 mm.

[0154] (Heat Seal Strength - After Acceleration) The resulting laminate was cut into a 12 cm x 30 cm piece. The long side of the film was folded in half, and two sides were heat-sealed at 180°C, 0.1 MPa, and 1 second. 5 g of contents were then placed inside, and the remaining side was heat-sealed under the same conditions to create a three-sided seal. A PET film was placed between the laminate and the heat seal bar to prevent direct contact between them. The bag was left at 50°C for 4 weeks, then opened and the contents were wiped off. A 15 mm-wide sample was cut from the heat-sealed portion, and both ends of the sample were fixed to a tensile tester and measured in tensile mode (tensile speed: 300 mm / min). Five measurements were performed under the same conditions, and the average was used as the heat seal strength. The unit is N / 15 mm. The contents used were Attack Antibacterial EX Super Clear Gel (Kao Corporation) and Merit Shampoo-DE1 (Kao Corporation).

[0155] (Aroma Retention) The resulting laminate was cut into a 7 cm x 16 cm piece. The long side of the film was folded in half, and two sides were heat-sealed at 160°C for 1 second. 5 g of contents were then placed inside, and the remaining side was heat-sealed to create a three-sided seal. The bag was immediately placed in a mayonnaise bottle (M-70) manufactured by Kakuyo Glass Co., Ltd., sealed, and stored at 40°C and 60% relative humidity for 3 days. A sensory evaluation was conducted by four panelists on a 5-point scale, and the average evaluation results of each panelist are summarized in Tables 1 and 2. A score closer to 1 indicates the absence of odor and excellent aroma retention of the laminate, while a score closer to 5 indicates a stronger odor. The contents used were Attack Antibacterial EX Super Clear Gel (manufactured by Kao Corporation) and Merit Shampoo-DE1 (manufactured by Kao Corporation).

[0156]

Claims

1. A stretched polyethylene film; An ethylene-based heat seal layer having a thickness of 45 μm to 250 μm; a coating layer disposed between the stretched polyethylene film and the ethylene-based heat seal layer; an adhesive layer disposed between the stretched polyethylene film and the ethylene-based heat seal layer; It does not include an inorganic vapor deposition layer, or a coating layer having gas barrier properties which is a dried coating film of a coating agent containing a resin having gas barrier properties and an aqueous solvent, the coating layer is a cured coating film of a coating agent containing a polyester polyol having a skeleton derived from an ortho-oriented aromatic carboxylic acid and a polyisocyanate, The adhesive layer is a cured coating film of an adhesive containing a polyester polyol having a skeleton derived from an ortho-oriented aromatic carboxylic acid and a polyisocyanate.

2. 2. The liquid packaging laminate according to claim 1, further comprising a heat-resistant coating layer on the surface of said stretched polyethylene film opposite to said coating layer.

3. 2. The laminate for liquid packaging according to claim 1, wherein the adhesive is a solvent-free adhesive.

4. The laminate for liquid packaging according to claim 1 , further comprising a print layer.

5. A laminate for liquid packaging material as described in claim 1, wherein the coating agent contains a drying aid.

6. A laminate for liquid packaging material as described in claim 1, wherein the coating agent contains an anti-skinning agent.

7. A liquid packaging material obtained by forming a bag from the laminate according to any one of claims 1 to 6.

8. A surface member, a back member, and a bottom member, The front member, the rear member, and the bottom member are the laminate according to any one of claims 1 to 6, The front member and the back member are overlapped and the left and right side edge portions are heat-sealed, The front member and the bottom member are heat-sealed, The liquid packaging material has the back member and the bottom member heat-sealed together.

9. A liquid packaging material as described in claim 8, wherein the front member, the back member and the bottom member are laminated bodies of the same configuration.

10. A liquid packaging material as described in claim 8, wherein the front member, the back member and the bottom member are laminates of different configurations.