Sealant film and packaging material

Abstract

Provided are: a sealant film which includes at least a base material layer and a sealing layer, wherein the base material layer contains a propylene-based block copolymer and an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer, the sealing layer contains a propylene-based block copolymer, and the proportion of a polypropylene-based resin is 85 mass% or more relative to the total amount of resin components that constitute the sealant film; a layered product comprising said sealant film as a sealant; and a packaging material containing said layered product.

Description

Sealant films and packaging materials

[0001] The present invention relates to a sealant film used for retort packaging, etc., which allows food or the like to be sterilized or cooked by heating or pressurizing while packaged, and to a packaging material using the sealant film.

[0002] Flexible packaging made from plastic materials is used worldwide as a food packaging material, and its use is showing an increasing trend as it spreads to emerging countries. In this context, retort foods, which are sterilized by high-temperature pressure and heat (retort sterilization), are expected to see increased demand in the future food packaging market due to their convenience. Retort foods can be distributed at room temperature, and in addition to being easy to eat, they are also easy to handle during distribution, and their expansion into regions where the cold chain is not yet fully developed is expected. Furthermore, because retort foods are distributed at room temperature for long periods of time, the packaging material must have excellent impact resistance.

[0003] On the other hand, conventional retort food packaging materials containing an aluminum layer cannot be used in microwave ovens and have little effect in promoting sales because the contents cannot be seen. Therefore, in recent years, various transparent retort food packaging materials have been proposed (for example, Patent Document 1).

[0004] Propylene-based resins have excellent heat resistance and are therefore used in food packaging films for high-temperature retort (sterilization treatment at 121 to 135°C) (see, for example, Patent Documents 2 and 3). However, there has been a demand for food packaging materials for high-temperature retort that can satisfy all of the following requirements: improved heat resistance, transparency, impact resistance, and high seal strength.

[0005] International Publication No. 2023 / 032580 International Publication No. 2019 / 189486 International Publication No. 2017 / 098953

[0006] The problem to be solved by the present invention is to provide a sealant film that has satisfactory transparency and impact resistance and has good sealing properties even after retort treatment, and a packaging material for retort packaging that uses the sealant film.

[0007] The present invention solves the above problems by providing a sealant film comprising at least a base layer and a seal layer, wherein the base layer comprises a propylene-based block copolymer and an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer, the seal layer comprises a propylene-based block copolymer, and the proportion of polypropylene-based resin relative to the total amount of resin components constituting the sealant film is 85 mass% or more.

[0008] The present invention also provides a sealant film in which the content of the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer in the sealant film is 2 to 20% by mass.

[0009] The present invention also provides a sealant film in which the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer is an ethylene-butene copolymer.

[0010] Furthermore, the present invention provides a laminate using the above sealant film as a sealant, and a packaging material containing the same.

[0011] The sealant film of the present invention has the above-mentioned structure, and satisfies all of the requirements of heat resistance, transparency, and impact resistance in addition to good sealing properties. Therefore, packaging materials using the sealant film of the present invention can be suitably used for packaging various foods, etc., particularly for high-speed retort packaging.

[0012] The sealant film of the present invention comprises at least a base layer and a seal layer, wherein the base layer comprises a propylene-based block copolymer and an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer, and the seal layer comprises a propylene-based block copolymer.

[0013] <Substrate Layer> The sealant film of the present invention includes at least a substrate layer, which includes a propylene-based block copolymer and an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer.

[0014] <Propylene-Based Block Copolymer> The propylene-based block copolymer may be a resin containing propylene and another α-olefin. Examples of α-olefins include ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Among these, ethylene is preferred due to its excellent heat resistance and impact resistance. The polymerization method for the propylene-based block copolymer is not particularly limited, but may be, for example, a first step in which a polymer block mainly composed of propylene is polymerized, and a second step in which an α-olefin and propylene copolymer block is polymerized. The propylene-based block copolymer is not a block copolymer in which a propylene polymer end and an α-olefin-propylene copolymer end are bonded, but rather a type of blend copolymer. However, a mixture of a propylene polymer and an α-olefin-propylene copolymer in pellet form is different from a propylene-based block copolymer exhibiting an island-sea structure.

[0015] The melting point of the propylene-based block copolymer is preferably 155 to 165°C, more preferably 157 to 163°C, in view of the balance between heat resistance and impact resistance.

[0016] The density of the propylene-based block copolymer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.89 g / cm ３ ~0.93 g / cm ３ is preferred, and 0.90 g / cm ３ ~0.92 g / cm ３ is more preferred.

[0017] The melt flow rate (MFR) of the propylene-based block copolymer is preferably 0.5 to 10 g / 10 min (230°C, 21.18 N), and more preferably 2 to 5 g / 10 min, because molding is easy and suitable impact resistance can be easily obtained.

[0018] The propylene-based block copolymer used in the present invention is preferably a propylene-based block copolymer that exhibits a haze of 30% or less, preferably 20% or less, and more preferably 10% or less, when the molten resin is extruded through a T-die and cooled on a cooling roll at 40°C to form a monolayer film with a thickness of 60 μm. The propylene-based block copolymer is a resin containing propylene and an elastomer component such as another α-olefin. A resin with this haze is a resin in a phase state in which elastomeric domains are finely dispersed, preferably in a streaky form. Therefore, it is presumed that the straightness of the tear is less likely to be hindered when torn, compared to a resin in a phase state in which large domains are dispersed, and that this allows for favorable tearing. The haze is measured in accordance with JIS K7105.

[0019] The content of the propylene-based block copolymer is preferably 50% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 95% by mass or less, and even more preferably 70% by mass or more and 95% by mass or less, based on the total amount of resin components contained in the base layer. Within this range, it is easy to achieve both rigidity and impact strength.

[0020] <Ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer> The sealant film of the present invention further contains an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer in its base layer. The ethylene-α-olefin copolymer and / or the propylene-α-olefin copolymer are obtained by copolymerizing ethylene and / or propylene with an α-olefin. The α-olefin is an α-olefin having 3 to 20 carbon atoms, preferably propylene, 1-butene, 1-heptene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 2-methyl-1-propene, 2-methyl-1-butene, 3-methyl-1-butene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-pentene, 6-methyl-1-pentene, 7-methyl-1-pentene, 8-methyl-1-pentene, 9-methyl-1-pentene, 10-methyl-1-pentene, 11-methyl-1-pentene, 12-methyl-1-pentene, 13-methyl-1-pentene, 14-methyl-1-pentene, 15-methyl-1-pentene, 16-methyl-1-pentene, 17-methyl-1-pentene, 18-methyl-1-pentene, 19-methyl-1-pentene, 20-methyl-1-pentene, 21-methyl-1-pentene, 22-methyl-1-pentene, 23-methyl-1-pentene, 24-methyl-1-pentene, 25-methyl-1-pentene, 26-methyl-1-pentene, 27-methyl-1-pentene, 28-methyl-1-pentene, Examples of the α-olefin include methyl-1-pentene, 3,3-dimethyl-1-butene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, methylethyl-1-butene, methyl-1-pentene, ethyl-1-hexene, dimethyl-1-hexene, propyl-1-heptene, methylethyl-1-heptene, trimethyl-1-pentene, propyl-1-pentene, diethyl-1-butene, etc. Among these, the α-olefin is preferably propylene, 1-butene, 1-pentene, 1-hexene, or 1-octene, more preferably 1-butene, 1-pentene, or 1-hexene, and particularly preferably 1-butene. That is, the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer is preferably an ethylene-propylene copolymer, an ethylene-butene copolymer, an ethylene-pentene copolymer, an ethylene-hexene copolymer, an ethylene-octene copolymer, a propylene-butene copolymer, a propylene-pentene copolymer, a propylene-hexene copolymer, or a propylene-octene copolymer, more preferably an ethylene-butene copolymer, an ethylene-pentene copolymer, an ethylene-hexene copolymer, a propylene-butene copolymer, a propylene-pentene copolymer, or a propylene-hexene copolymer, and particularly preferably an ethylene-butene copolymer or a propylene-butene copolymer. The α-olefin may be used alone or in combination of two or more.The ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer may be used alone or in combination. The ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer has good compatibility with the propylene-based block copolymer, and therefore the sealant film of the present invention and the laminate or packaging material using the same have good impact resistance.

[0021] The melt flow rate (MFR) of the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer is preferably 0.5 to 10 g / 10 min (190°C, 21.18 N), and more preferably 2 to 9 g / 10 min, since this facilitates obtaining favorable tear properties. When the MFR is in this range, favorable moldability is easily obtained when blended with a propylene-based block copolymer.

[0022] The density of the ethylene-α-olefin copolymer and / or the propylene-α-olefin copolymer is 0.850 to 0.943 g / cm ３ It may be appropriately selected depending on the purpose of modifying the propylene-based block copolymer, such as impact resistance or achieving both impact resistance and rigidity. When it is particularly desired to improve impact resistance, it is 0.850 to 0.910 g / cm ３ It is preferable that:

[0023] The content of the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer is preferably 1% by mass or more and 50% by mass or less, more preferably 2% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less, relative to the total amount of resin components contained in the base layer. Within this range, retort resistance is improved. When multiple types of ethylene-α-olefin copolymers and / or propylene-α-olefin copolymers are used in combination, the content refers to the total content of the multiple types of ethylene-α-olefin copolymers and / or propylene-α-olefin copolymers.

[0024] In the present invention, the base layer preferably uses only the propylene-based block copolymer and ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer as resin components, but it is also preferable to use a high melt tension polypropylene resin in combination. The high melt tension polypropylene resin has a structure in which long chain branches are introduced into the main chain of the polypropylene resin or a crosslinked structure, thereby increasing the tension when melted. The inclusion of a high melt tension polypropylene resin increases the rigidity of the film through oriented crystallization, promoting ease of tearing. In particular, when forming a film by the inflation method, this is preferable because it enables stable film formation even with polypropylene-based resins, which have traditionally been difficult to form by inflation molding due to their weak melt tension.

[0025] The content of the high melt tension polypropylene resin in the resin component of the sealant film is preferably 0.1 to 25% by mass, more preferably 2 to 20% by mass, which makes it easier to achieve favorable film-forming properties and impact resistance.

[0026] The composition of the high melt tension polypropylene resin may be any of propylene homopolymer, propylene-ethylene random copolymer, or propylene-ethylene block copolymer, but propylene homopolymer type is preferred in terms of heat resistance. The melt flow rate (MFR) is preferably 0.1 to 18 g / 10 min (230°C, 21.18 N), more preferably 0.5 to 8 g / 10 min (230°C, 21.18 N), and even more preferably 0.8 to 6.0 g / 10 min (230°C, 21.18 N). This facilitates obtaining favorable film-forming properties and good compatibility with propylene-based block copolymers.

[0027] The substrate layer in the present invention may also contain other resins in combination, such as propylene-based resins such as propylene homopolymers and propylene-α-olefin random copolymers (propylene-ethylene copolymers, propylene-butene-1 copolymers, propylene-ethylene-butene-1 copolymers, metallocene catalyst-based polypropylenes, etc.), polyethylene resins such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and low density polyethylene (LDPE), as well as ethylene-vinyl acetate copolymers (EVA), ethylene-methyl methacrylate copolymers (EMMA), ethylene-ethyl acrylate copolymers (EEA), ethylene-methyl acrylate copolymers (EMA), ethylene-ethyl acrylate-maleic anhydride copolymers (E-EA-MAH), and ethylene-acrylic acid copolymers. ethylene copolymers such as ethylene-acrylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA); cyclic polyolefin resins such as ionomers of ethylene-acrylic acid copolymer and ionomers of ethylene-methacrylic acid copolymer, norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers; ethylene-α-olefin copolymers such as ethylene-propylene copolymer rubber (EPR), ethylene-1-butene copolymer rubber (EBR), ethylene-1-pentene copolymer rubber, ethylene-1-hexene copolymer rubber (EHR), and ethylene-1-octene copolymer rubber (EOR); propylene-1-butene copolymer rubber (PBR), propylene-1-pentene copolymer rubber, and propylene-1-octene copolymer (POR).

[0028] Furthermore, as the olefin-based resin other than the ethylene-based resin, a cyclic polyolefin-based resin may be used. However, the content of the cyclic polyolefin-based resin in the resin components contained in the base layer is preferably 10% by mass or less, more preferably 5% by mass or less, and it is also preferable to use substantially no cyclic polyolefin-based resin. Examples of such cyclic olefin-based resins include norbornene-based polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene-based polymers are preferred. Furthermore, examples of norbornene-based polymers include ring-opening polymers (COPs) of norbornene-based monomers and norbornene-based copolymers (COCs) copolymerized with norbornene-based monomers and olefins such as ethylene. Furthermore, hydrogenated products of COPs and COCs are particularly preferred. Furthermore, the weight-average molecular weight of the cyclic olefin-based resin is preferably 5,000 to 500,000, more preferably 7,000 to 300,000.

[0029] The norbornene-based polymer and the norbornene-based monomer used as a raw material are alicyclic monomers having a norbornene ring. Examples of such norbornene-based monomers include norbornene, tetracyclododecene, ethylidenenorbornene, vinylnorbornene, ethylidetetracyclododecene, dicyclopentadiene, dimethanotetrahydrofluorene, phenylnorbornene, methoxycarbonylnorbornene, and methoxycarbonyltetracyclododecene. These norbornene-based monomers may be used alone or in combination of two or more.

[0030] The norbornene-based copolymer is obtained by copolymerizing the norbornene-based monomer with a copolymerizable olefin. Examples of such olefins include olefins having 2 to 20 carbon atoms, such as ethylene, propylene, and 1-butene; cycloolefins, such as cyclobutene, cyclopentene, and cyclohexene; and non-conjugated dienes, such as 1,4-hexadiene.

[0031] As the polyethylene resin, biomass-derived polyethylene may be used, for example, biomass-derived low-density polyethylene (trade name: SBC818, density: 0.918 g / cm) manufactured by Braskem. ３ , MFR: 8.1 g / 10 min), and biomass-derived low-density polyethylene manufactured by Braskem (trade name: SPB681, density: 0.922 g / cm ３ , MFR: 3.8 g / 10 min), and biomass-derived linear low-density polyethylene manufactured by Braskem (trade name: SLL118, density: 0.916 g / cm ３ , MFR: 1.0 g / 10 min).

[0032] When such other resins are used, the content of the other resins is preferably 2 to 20% by mass, more preferably 2 to 15% by mass, of the resin components contained in the sealant film. By setting the content within this range, it is easy to improve impact resistance and also easy to obtain good heat resistance and rigidity.

[0033] The substrate layer of the present invention may contain various additives within the range that does not impair the effects of the present invention. Examples of such additives include antioxidants, heat stabilizers, weathering stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, release agents, UV absorbers, colorants such as pigments, biodegradation-promoting additives, and compatibilizers. When these additives are used, they are preferably used in an amount of 15 parts by mass or less, more preferably about 0.01 to 10 parts by mass, per 100 parts by mass of the resin components used in the substrate layer.

[0034] In particular, in order to impart processability during film molding and packaging suitability in filling machines, it is preferable that the friction coefficient of the base layer and seal layer that form the surface of the sealant film of the present invention is 1.5 or less, and in particular 1.0 or less, and therefore it is preferable to add a lubricant or an anti-blocking agent to the base layer and seal layer as appropriate.

[0035] <Sealing Layer> The sealant film of the present invention includes at least a sealing layer. The sealing layer includes a propylene-based block copolymer. The propylene-based block copolymer used in the sealing layer can be the same as the propylene-based block copolymer used in the base layer, and the same is also preferred. The propylene-based block copolymers used in the sealing layer and the base layer may be the same, or propylene-based block copolymers exhibiting different physical properties may be used.

[0036] The content of the propylene-based block copolymer is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 95% by mass, and even more preferably 70% by mass to 95% by mass, based on the total amount of resin components contained in the seal layer. Within this range, it is easy to achieve both rigidity and impact strength.

[0037] The sealing layer in the sealant of the present invention preferably further contains an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer. The ethylene-α-olefin copolymer and / or the propylene-α-olefin copolymer can be the same as the ethylene-α-olefin copolymer and / or the propylene-α-olefin copolymer used in the base layer, and the same is also preferred. The ethylene-α-olefin copolymer and / or the propylene-α-olefin copolymer used in the sealing layer and the base layer may be the same, or ethylene-α-olefin copolymers and / or propylene-α-olefin copolymers exhibiting different physical properties may be used. The sealing layer in the sealant of the present invention may further contain another resin. Examples of the other resin include the same resins that may be used in the base layer.

[0038] The content of the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer is preferably 0% by mass or more and 50% by mass or less, more preferably 0% by mass or more and 30% by mass or less, and even more preferably 2% by mass or more and 20% by mass or less, relative to the total amount of resin components contained in the seal layer. Within this range, retort resistance is improved. When multiple types of ethylene-α-olefin copolymers and / or propylene-α-olefin copolymers are used in combination, the content refers to the total content of the multiple types of ethylene-α-olefin copolymers and / or propylene-α-olefin copolymers.

[0039] The sealing layer of the present invention may contain various additives as long as they do not impair the effects of the present invention. Examples of such additives include antioxidants, heat stabilizers, weather stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, release agents, UV absorbers, colorants such as pigments, biodegradation-promoting additives, and compatibilizers. When these additives are used, they are preferably used in an amount of 15 parts by mass or less, more preferably 0.01 to 10 parts by mass, per 100 parts by mass of the resin components used in the sealing layer.

[0040] In particular, in order to impart processability during film molding and packaging suitability in filling machines, it is preferable that the friction coefficient of the base layer and seal layer that form the surface of the sealant film of the present invention is 1.5 or less, and in particular 1.0 or less, and therefore it is preferable to add a lubricant or an anti-blocking agent to the base layer and seal layer as appropriate.

[0041] (Intermediate Layer) The sealant film of the present invention may further include one or more intermediate layers in addition to the substrate layer and the seal layer. Resins that can be used for the intermediate layer include the resins exemplified for the substrate layer, such as the propylene-based block copolymer, the ethylene-α-olefin copolymer and / or the propylene-α-olefin copolymer, and the other resins, and the preferred resins are also the same. Furthermore, from the viewpoint of interlayer adhesion, the intermediate layer may have the same composition as the substrate layer, or a different composition.

[0042] The resin used as the resin component of the intermediate layer may include recycled film ends, etc., generated during the production of the sealant film of the present invention and recycled film ends, etc., generated during the production of a propylene-based film. Here, a propylene-based film refers to a film in which the proportion of the propylene-based resin in the total resin content of the film is 70% by mass or more. When the recycled material is added to the intermediate layer, its content is preferably 1 to 55% by mass, more preferably 5 to 55% by mass, even more preferably 10 to 53% by mass, and even more preferably 15 to 47% by mass of the resin component contained in the intermediate layer. When the recycled material is added, the film ends may be crushed and added as fluff, or the film ends may be kneaded and added as pellets.

[0043] The intermediate layer may contain various additives as long as they do not impair the effects of the present invention. Examples of such additives include antioxidants, heat stabilizers, weather stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, release agents, UV absorbers, colorants such as pigments, biodegradation-promoting additives, and compatibilizers. When these additives are used, they are preferably used in an amount of 15 parts by mass or less, more preferably about 0.01 to 10 parts by mass, per 100 parts by mass of the resin components used in the intermediate layer.

[0044] <Sealant Film> The sealant film of the present invention includes at least a substrate layer and a seal layer. Examples of layer configurations include, but are not limited to, substrate layer / seal layer, substrate layer / intermediate layer / seal layer, and substrate layer / intermediate layer / intermediate layer / seal layer. Furthermore, a laminate of substrate layer / intermediate layer / seal layer is preferred. The sealant film may include two or more intermediate layers. In this case, it is sufficient that at least one of all the intermediate layers has the resin configuration described above. Furthermore, when two or more intermediate layers are included, the thickness ratio when all the intermediate layers are considered as one layer may be within the range described below.

[0045] Furthermore, the sealant film of the present invention has a polypropylene resin ratio of 85% by mass or more relative to the total amount of resin components constituting the sealant film. By having this polypropylene resin ratio of 85% by mass or more, high heat resistance is achieved and high retort suitability is suitably exhibited. Furthermore, a polypropylene resin ratio of 90% by mass or more is more preferable because the sealant film becomes a mono-material film, facilitating recycling. The polypropylene resin includes propylene homopolymers, propylene-α-olefin random copolymers (propylene-ethylene copolymers, propylene-butene copolymers, propylene-ethylene-butene copolymers, metallocene catalyst-based polypropylenes, etc.), and the above-mentioned propylene block copolymers.

[0046] The content of the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer in the sealant film of the present invention is preferably 2 to 20% by mass. When the content is within this range, packaging bags are less likely to be damaged, particularly by falling objects. The content is more preferably 5 to 17% by mass, and even more preferably 7 to 15% by mass. When multiple types of ethylene-α-olefin copolymers and / or propylene-α-olefin copolymers are used in combination, the content refers to the total content of the multiple types of ethylene-α-olefin copolymers and / or propylene-α-olefin copolymers.

[0047] The thickness of the seal layer of the present invention is preferably 2.0 μm to 30 μm, more preferably 2.0 μm to 20 μm. The thickness of the intermediate layer is preferably 10 to 130 μm, more preferably 10 to 120 μm, and even more preferably 10 to 80 μm. From the viewpoint of film properties, the thickness of the base layer is preferably 2.0 to 60 μm, more preferably 5.0 to 50 μm, and even more preferably 10 to 40 μm.

[0048] The thickness of the sealing layer is preferably in the range of 5 to 30% of the total thickness of the sealant film of the present invention, more preferably 7 to 20%. When the ratio of the thickness of the sealing layer to the total thickness of the sealant film is within this range, the sealability is excellent. The thickness of the intermediate layer is preferably in the range of 25 to 90% of the total thickness of the sealant film of the present invention, more preferably 25 to 80%. When the ratio of the thickness of the intermediate layer to the total thickness of the sealant film is within this range, the transparency, tearability, pinhole resistance, and sealability are improved. The thickness of the base layer is preferably 10 to 40% of the thickness of the sealant film of the present invention, more preferably 15 to 35%, from the viewpoints of film rigidity, packaging suitability, transparency, surface gloss, and ease of lateral tearing.

[0049] Furthermore, from the viewpoints of heat resistance in packaging applications, resistance to bag breakage during distribution, heat sealing properties, etc., the sealant film of the present invention preferably has a total thickness of 20 to 150 μm, more preferably 40 to 100 μm.

[0050] The sealant film of the present invention preferably contains 70% by mass or more of the propylene-based block copolymer in the resin component. By achieving this range, heat resistance and tear resistance suitable for packaging bags can be achieved. This content is preferably 75% by mass or more, and more preferably 80% by mass or more, of the resin component. When the sealant film of the present invention has a multilayer structure, it is preferable that the content of the propylene-based block copolymer in each layer be within this range. When the sealant film contains recycled materials, the content of the propylene-based block copolymer can be calculated taking into account the resin composition of the film end portion added as the recycled material. That is, if the resin composition of the film end portion is known, the content of the propylene-based block copolymer contained in the recycled material can be calculated from the known resin composition, and the content of the propylene-based block copolymer relative to the total amount of resin components contained in the entire sealant film can be calculated. On the other hand, if the resin composition of the film end is not known, the resin composition of the recovered product may be analyzed in advance by some analytical method such as nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), differential scanning calorimetry (DSC), etc. However, since an analytical step is required, in one embodiment of the present invention, it is preferable that the resin composition of the recovered product is known.

[0051] (Method for Producing Sealant Film) The method for producing the sealant film of the present invention is not particularly limited, but examples include a coextrusion method in which the resins or resin mixtures used for the base layer, intermediate layer, and seal layer are heated and melted in separate extruders, and then laminated in the molten state in the order of base layer / intermediate layer / seal layer by a method such as a coextrusion multilayer die method or a feed block method, and then formed into a film by inflation or a T-die method. This coextrusion method is preferred because it allows relatively free adjustment of the thickness ratio of each layer and produces a sealant film that is excellent in hygiene and cost performance. The inflation method can be used to produce a film by heating and melting the resins used to produce the film, or the resins used for each layer in the case of a multilayer structure, in an extruder and coextruding them into a film by inflation using a multilayer circular die. Among these, the T-die method, which allows melt extrusion at a relatively high temperature, is preferred because it is easy to suppress deterioration of the film's appearance during coextrusion processing and to easily form a uniform layer structure.

[0052] As the inflation method, the air-cooled inflation method is preferred, and the upward air-cooled inflation method is particularly preferred. When a single-layer film is produced, one extruder and a single-layer circular die are used, and when a multi-layer film is produced, multiple extruders and a multi-layer circular die are used. Using these extruders, a cylindrical molten resin is extruded upward, and then, if necessary, the cylindrical molten resin is expanded and taken up, and the molten resin is cooled and solidified by air cooling, and then appropriately cut to obtain a desired film.

[0053] When the resin mixture is laminated to each layer, the dry-blended resin mixture can be directly extruded using a co-extruder for lamination. Alternatively, the resin mixture can be melt-blended in advance using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer, and then pelletized and extruded using a co-extruder for lamination.

[0054] The sealant film of the present invention can be obtained as a substantially unstretched multilayer film by the above-mentioned production method, and therefore can be subjected to secondary forming such as deep drawing by vacuum forming.

[0055] Immediately after extrusion of the base layer or the seal layer, the layer may be brought into contact with a roll having projections and recesses to be embossed.

[0056] Furthermore, in order to improve adhesion to printing ink and suitability for lamination, it is preferable to subject the substrate layer to a surface treatment, such as a corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment, or other surface oxidation treatment, or a surface roughening treatment such as sandblasting, with corona treatment being preferred.

[0057] (Laminate) The sealant film of the present invention can be laminated, for example by bonding it to a substrate, to form a laminate. The laminate of the present invention may have the following configuration: (1) substrate / adhesive layer / sealant film of the present invention (2) substrate / adhesive layer / printed layer / sealant film of the present invention (3) substrate / adhesive layer / second substrate / printed layer / adhesive layer / sealant film of the present invention (4) substrate / adhesive layer / first printed layer / second printed layer / sealant film of the present invention (5) substrate / adhesive layer / barrier layer / adhesive layer / sealant film of the present invention (6) substrate / adhesive layer / barrier layer / printed layer / adhesive layer / sealant film of the present invention (7) substrate / printed layer / adhesive layer / sealant film of the present invention (8) substrate / first printed layer / second printed layer / adhesive layer / sealant film of the present invention (9) substrate / printed layer / adhesive layer / barrier layer / adhesive layer / sealant film of the present invention (10) substrate / adhesive layer / barrier layer / adhesive layer / second substrate / adhesive layer / sealant film of the present invention (11) substrate / printed layer / adhesive layer / barrier layer / adhesive layer / second substrate / adhesive layer / sealant film of the present invention Examples include, but are not limited to, and may further include an additional substrate. Furthermore, when multiple adhesive layers are included, each may be an adhesive layer of the same composition or may be a different adhesive layer, and the thicknesses of the multiple adhesive layers may be the same or different, without any particular limitation. The second and additional substrates may be unstretched resin films, stretched resin films, metal-deposited films such as metal-deposited unstretched films and metal-deposited stretched films, or transparent vapor-deposited films, without any particular limitation. Furthermore, the multiple adhesive layers may have the same composition or different compositions. Furthermore, an anchor coat layer may be sandwiched between the layers to improve the adhesive strength of the adhesive layers. Furthermore, a coating layer that imparts functions such as release properties and antistatic properties may be present on the substrate.

[0058] (Substrate) The substrate is not particularly limited, and examples thereof include polyolefin films such as polyethylene terephthalate (PET) film, polybutylene terephthalate (PBT) film, polystyrene film, polyamide film, nylon film, polyacrylonitrile film, polyethylene film (OPE: biaxially oriented polyethylene film, LLDPE: low-density polyethylene film, HDPE: high-density polyethylene film) and polypropylene film (CPP: non-oriented polypropylene film, OPP: biaxially oriented polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, cellophane, etc.

[0059] Furthermore, films obtained by laminating an inorganic vapor-deposited layer of a metal oxide such as silica or alumina on these films can also be used. Specific examples include OPE films, OPP films, PET films, PBT films, and nylon films each having a silica vapor-deposited layer, and OPE films, OPP films, PET films, PBT films, and nylon films each having an alumina vapor-deposited layer.

[0060] When mono-material packaging is considered, a film made of a thermoplastic resin primarily composed of an olefin-based resin can be used as the substrate. Specific examples of olefin-based resins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear (linear) low-density polyethylene; polypropylene; ethylene-propylene copolymers; α-olefin polymers; ethylene-vinyl acetate copolymers; ethylene-vinyl alcohol copolymers; ethylene-acrylic acid copolymers; ethylene-methyl methacrylate copolymers; ethylene-ethyl acrylate copolymers; cyclic olefin resins; ionomer resins; and polymethylpentene; as well as modified olefin-based resins obtained by modifying olefin resins with acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, or other unsaturated carboxylic acids. Using polypropylene as the substrate allows the sealant film of the present invention to be a mono-material polypropylene film, which is preferable for reducing environmental impact. For example, a mono-material film can be obtained using a configuration such as OPP / vapor-deposited OPP / sealant film of the present invention, OPP / printed layer / vapor-deposited OPP / sealant film of the present invention, or OPP / metal foil / sealant film of the present invention. From the viewpoint of the heat resistance of OPP, when heat sealing such a mono-material film, it is preferable to use ultrasonic sealing, but this is not limitative.

[0061] It is also preferable to use a film formed from a material containing biomass-derived components as the film substrate. Biomass films are commercially available from various companies, and for example, films and sheets such as those listed in the list of biomass-certified products listed by the Japan Organics Recycling Association can be used.

[0062] Specifically, well-known films are made from biomass-derived ethylene glycol. Biomass-derived ethylene glycol is made from ethanol (biomass ethanol) produced from biomass as a raw material. For example, biomass-derived ethylene glycol can be obtained by converting biomass ethanol into ethylene oxide by a conventionally known method to produce ethylene glycol. Alternatively, commercially available biomass ethylene glycol may be used; for example, biomass ethylene glycol commercially available from India Glycoal Limited can be suitably used.

[0063] Alternatively, products using biomass raw materials classified by the biomass plastic content specified in ISO 16620 or ASTM D6866 are also on the market. Radioactive carbon-14C exists in the atmosphere at a rate of 1 in 10 particles, and this rate is the same for atmospheric carbon dioxide, so this rate remains the same even in plants that fix this carbon dioxide through photosynthesis. Therefore, the carbon in plant-derived resins contains radioactive carbon-14C. In contrast, the carbon in fossil fuel-derived resins contains almost no radioactive carbon-14C. Therefore, by measuring the concentration of radioactive carbon-14C in the resin using an accelerator mass spectrometer, the plant-derived resin content in the resin, i.e., the biomass plastic content, can be determined. Examples of plant-derived low-density polyethylene, which is a biomass plastic having a biomass plastic content of 80% or more, preferably 90% or more as specified by ISO 16620 or ASTM D6866, include products manufactured by Braskem under the trade names "SBC818," "SPB608," "SBF0323HC," "STN7006," "SEB853," and "SPB681," and films using these as raw materials can be suitably used.

[0064] For example, biomass polyolefin films, such as biomass polyethylene films and biomass polyethylene-polypropylene films, containing polyethylene resins made from biomass-derived ethylene glycol are known as alternatives to conventional polyolefin films made from petroleum-based raw materials. The polyethylene resin is not particularly limited except that the biomass-derived ethylene glycol is used as part of the raw material. Examples of the polyethylene resin include ethylene homopolymers and copolymers of ethylene and α-olefins containing ethylene as the main component (ethylene-α-olefin copolymers containing 90% by mass or more of ethylene units). These can be used alone or in combination of two or more. The α-olefin constituting the copolymer of ethylene and α-olefin is not particularly limited, and examples include α-olefins having 4 to 8 carbon atoms, such as 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Known polyethylene resins, such as low-density polyethylene resins, medium-density polyethylene resins, and linear low-density polyethylene resins, can be used. Among these, from the viewpoint of making it more difficult for damage such as holes or tears to occur even when films are rubbed against each other, linear low-density polyethylene resin (LLDPE) (a copolymer of ethylene and 1-hexene, or a copolymer of ethylene and 1-octene) is preferred, and the density is 0.905 to 0.937 g / cm ３ A linear low-density polyethylene resin having a density of 0.910 to 0.925 g / cm is more preferred. ３ More preferred is a linear low density polyethylene resin in which

[0065] The biomass film may be a laminate of multiple biomass films, or may be a laminate of a conventional petroleum-based film and a biomass film.

[0066] The substrate may be one that has been subjected to some kind of surface treatment, for example, a physical treatment such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, or flame treatment, or a chemical treatment such as oxidation treatment using chemicals, or other treatment.

[0067] The substrate can be produced from the resins described above by a conventionally known film-forming method such as extrusion, cast molding, T-die molding, cutting, inflation, etc. The substrate may be an unstretched film, or may be one that has been stretched uniaxially or biaxially using a tenter system, a tubular system, or the like, from the viewpoint of film strength, dimensional stability, and heat resistance.

[0068] The substrate may contain additives as needed. Specifically, for the purpose of improving or modifying processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, mold releasability, flame retardancy, mildew resistance, electrical properties, strength, etc., plastic compounding agents such as elastomers, lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, antifogging agents, antiblocking agents, biodegradation-promoting additives, compatibilizers, pigments, and other additives may be added. The amount of additive added is adjusted within a range that does not affect other performance properties or recyclability.

[0069] The thickness of the substrate is not particularly limited and may be appropriately selected in the range of 0.1 to 300 μm from the viewpoint of formability and transparency. The thickness is preferably in the range of 0.3 to 100 μm. If the thickness of the substrate is 0.1 to 300 μm, good strength and processing stability can be obtained.

[0070] From the viewpoint of recycling, it is preferable that the layer structure is as simple as possible, but from the viewpoint of the distribution of the packaging material, it may include printing to display the contents of the packaging material or a description or name of the product.

[0071] (Adhesive Layer) In the present invention, the adhesive layer has the function of adhering any two layers constituting the laminate, for example, the base material layer and the second base material layer. The adhesive used in the adhesive layer may be any adhesive that can be used in a general-purpose lamination method. Examples of lamination methods include dry lamination, wet lamination, non-solvent lamination, extrusion lamination, sand lamination, and thermal lamination. After the adhesive has cured or dried, it becomes an adhesive layer.

[0072] The adhesive used in the dry lamination can be, for example, a one-component or two-component curing or non-curing vinyl-based, (meth)acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, rubber-based, or other solvent-based, water-based, or emulsion-based adhesive. A two-component curing adhesive made of a polyol and an isocyanate compound can be used. Of the above adhesives, a two-component curing adhesive made of a polyol composition and a polyisocyanate composition is preferred.

[0073] (Two-component curing adhesive) The two-component curing adhesive preferably contains a polyisocyanate composition (X) and a polyol composition (Y).

[0074] (Polyisocyanate Composition (X)) The polyisocyanate composition (X) is not particularly limited, and any polyisocyanate composition (X) used in the technical field of adhesives can be used. For example, a urethane prepolymer, a mixture of a urethane prepolymer and an isocyanate compound, or an isocyanate compound can be used.

[0075] (Urethane Prepolymer (A1)) The urethane prepolymer (hereinafter sometimes referred to as urethane prepolymer (A1)) is not particularly limited, and any urethane prepolymer used in the technical field of adhesives can be used. Generally, a urethane prepolymer obtained by reacting an isocyanate composition (i) with a polyol composition (ii) under conditions in which the isocyanate groups contained in the isocyanate group (i) are in excess relative to the active hydrogen groups contained in the polyol composition (ii) is used.

[0076] (Isocyanate composition (i)) The isocyanate composition (i) contains an isocyanate compound. The isocyanate compound is not particularly limited, and any isocyanate compound that can be commonly used in the synthesis of urethane prepolymers can be used as appropriate. Examples include aromatic diisocyanates, araliphatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and biuret, nurate, adduct, allophanate, carbodiimide-modified, and uretdione-modified products of these diisocyanates, as well as urethane prepolymers obtained by reacting these polyisocyanates with polyols, and these can be used alone or in combination.

[0077] Examples of the aromatic diisocyanate include, but are not limited to, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate (also referred to as polymeric MDI or crude MDI), 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate.

[0078] The araliphatic diisocyanate means an aliphatic isocyanate having one or more aromatic rings in the molecule, and examples thereof include, but are not limited to, m- or p-xylylene diisocyanate (also known as XDI), α,α,α',α'-tetramethylxylylene diisocyanate (also known as TMXDI), and the like.

[0079] Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate, but are not limited to these.

[0080] Examples of the alicyclic diisocyanate include 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate, isophorone diisocyanate (also known as IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and 1,4-bis(isocyanatemethyl)cyclohexane, but are not limited to these.

[0081] (Polyol Composition (ii)) The polyol composition (ii) used in the synthesis of the urethane prepolymer contains a polyol compound. The polyol compound is not particularly limited, and any polyol compound that can be commonly used in the synthesis of urethane prepolymers can be used as appropriate. For example, glycols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol;

[0082] Trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, pentaerythritol, etc.; bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, etc.; dimer diol; polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexylene, etc. in the presence of a polymerization initiator such as the above-mentioned glycols or trifunctional or tetrafunctional aliphatic alcohols; polyether urethane polyols obtained by further polymerizing polyether polyols with an isocyanate compound;

[0083] Polyester polyols (1) are reaction products of polyesters obtained by ring-opening polymerization of cyclic ester compounds such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, β-methyl-σ-valerolactone, and polyhydric alcohols such as the above glycols, glycerin, trimethylolpropane, and pentaerythritol; polyester polyols (2) are obtained by reacting bifunctional polyols such as the above glycols, dimer diols, or bisphenols with polycarboxylic acids; polyester polyols (3) are obtained by reacting trifunctional or tetrafunctional aliphatic alcohols with polycarboxylic acids; polyester polyols (4) are obtained by reacting bifunctional polyols, the above trifunctional or tetrafunctional aliphatic alcohols, and polycarboxylic acids; polyester polyols (5) are polymers of hydroxyl acids such as dimethylolpropionic acid and castor oil fatty acid;

[0084] Examples of the polyester polyether polyurethane polyol include polyester polyether polyurethane polyols obtained by reacting at least one of polyester polyols (1) to (5) with a polyether polyol and an isocyanate compound; polyester polyurethane polyols obtained by polymerizing polyester polyols (1) to (5) with an isocyanate compound; and castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil which is a hydrogenated castor oil, and castor oil alkylene oxide 5 to 50 mol adducts, and mixtures thereof.

[0085] Examples of polyvalent carboxylic acids used in the synthesis of the polyester polyols (2) to (4) include aromatic polybasic acids such as orthophthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic anhydride, naphthalic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic dianhydride, 5-sodium sulfoisophthalic acid, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride; and methyl esters of aromatic polybasic acids such as dimethyl terephthalic acid and dimethyl 2,6-naphthalenedicarboxylate.

[0086] Aliphatic polybasic acids such as malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, and itaconic acid; alkyl esters of aliphatic polybasic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate;

[0087] Alicyclic polybasic acids such as 1,1-cyclopentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, cyclohexane-1,2,4-tricarboxylic-1,2-anhydride, himic acid anhydride, and HET acid anhydride can be mentioned, and these can be used alone or in combination of two or more.

[0088] The isocyanate compound used in the synthesis of the polyurethane polyol may be the same as those exemplified for the isocyanate composition (i).

[0089] The polyol compound preferably contains at least one of polyether polyol, polyester polyol, and polyester polyurethane polyol.

[0090] When an amine compound is used in the polyol composition (ii) to introduce a urea derivative or a biuret derivative into the urethane prepolymer, the amine compound used preferably contains a primary or secondary monoamine compound.

[0091] Examples of the primary monoamine compound include aliphatic unsaturated primary amines such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, amylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine (laurylamine), tridodecylamine, tetradecylamine (myristylamine), pentadecylamine, cetylamine, stearylamine, oleylamine, cocoalkylamine, tallow alkylamine, hardened tallow alkylamine, and allylamine; aniline; and benzylamine.

[0092] Examples of the secondary monoamine compound include aliphatic unsaturated secondary amines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diamylamine, and diallylamine, methylaniline, ethylaniline, dibenzylamine, diphenylamine, dicocoalkylamine, di-hardened beef tallow alkylamine, and distearylamine.

[0093] The amount of the monoamine compound is preferably 40% by mass or less of the total amount of the polyol composition (ii).

[0094] The urethane prepolymer (A1) is obtained by reacting an isocyanate composition (i) with a polyol composition (ii) under conditions in which the isocyanate groups contained in the isocyanate group (i) are in excess relative to the active hydrogen groups contained in the polyol composition (ii). The equivalent ratio of the isocyanate groups to the active hydrogen groups contained in the polyol composition (ii), [NCO] / [active hydrogen groups], can be appropriately adjusted depending on the purpose, but is, for example, 2.0 or more and 20.0 or less.

[0095] (Isocyanate Compound (A2)) The isocyanate compound (hereinafter sometimes referred to as isocyanate compound (A2)) may be any isocyanate compound that can be commonly used in the synthesis of the urethane prepolymer of the isocyanate composition (i). It may also be a biuret, uretdione, nurate, adduct, allophanate, carbodiimide-modified product, or the like of the isocyanate compound. Specific examples include biuret, nurate, and allophanate forms of hexamethylene diisocyanate, nurate forms of isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate and / or 2,4'-diphenylmethane diisocyanate, and their biuret, nurate, adduct, allophanate, carbodiimide-modified forms, allophanate forms, polymeric diphenylmethane diisocyanate, and adducts of toluene diisocyanate and trimethylolpropane.

[0096] (Viscosity) When the polyisocyanate composition (X) is used as a solventless two-component curing adhesive, the viscosity of the polyisocyanate composition (X) is adjusted to a range suitable for the non-solvent lamination method. For example, the viscosity at 25°C is adjusted to a range of 1000 to 10000 mPas, more preferably 1000 to 5000 mPas. The viscosity of the polyisocyanate composition (X) can be adjusted, for example, by the amount of the urethane prepolymer and the isocyanate compound added.

[0097] (Polyol Composition (Y)) The polyol composition (Y) contains a polyol compound having multiple hydroxyl groups. There are no particular limitations on the polyol compound, and any polyol compound typically used in a urethane-reactive two-component curing adhesive can be used. Specific examples include polyether polyols, polyester polyols, polyester polyether polyols, polyurethane polyols, polyester polyurethane polyols, polyether polyurethane polyols, polyester amide polyols, vegetable oil polyols, sugar alcohols, polycarbonate polyols, acrylic polyols, hydroxyl group-containing olefin resins, hydroxyl group-containing fluororesins, and (poly)alkanolamines.

[0098] Examples of the polyether polyol include those obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and triethylene glycol; and trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, pentaerythritol, and triols of polypropylene glycol. Polypropylene glycol is preferably used.

[0099] The polyester polyol is a reaction product of a polyhydric alcohol and a polycarboxylic acid. The polyhydric alcohol used in the synthesis of the polyester polyol may be a diol or a tri- or higher functional polyol. Alternatively, a polyester polyether polyol using the polyether polyol described above as the diol, or a polyester polyurethane polyol using a polyurethane polyol described below, may be used. Examples of the diol include aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,2,2-trimethyl-1,3-propanediol, 2,2-dimethyl-3-isopropyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, and 2,2,4-trimethyl-1,3-pentanediol;

[0100] Ether glycols such as polyoxyethylene glycol and polyoxypropylene glycol; modified polyether diols obtained by ring-opening polymerization of aliphatic diols with various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether;

[0101] Lactone-based polyester polyols obtained by polycondensation reaction of aliphatic diols with various lactones such as lactanoids and ε-caprolactone;

[0102] bisphenols such as bisphenol A and bisphenol F;

[0103] Examples include alkylene oxide adducts of bisphenols obtained by adding ethylene oxide, propylene oxide, etc. to bisphenols such as bisphenol A and bisphenol F.

[0104] The tri- or higher functional polyols include aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol;

[0105] modified polyether polyols obtained by ring-opening polymerization of aliphatic polyols with various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether;

[0106] Examples include lactone-based polyester polyols obtained by polycondensation reaction of aliphatic polyols with various lactones such as ε-caprolactone.

[0107] Examples of polyvalent carboxylic acids used in the synthesis of the polyester polyol include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as orthophthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid; and anhydrides or ester-forming derivatives of these aliphatic or dicarboxylic acids; p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids; and polybasic acids such as dimer acid.

[0108] The polyurethane polyol is a reaction product of a low-molecular-weight or high-molecular-weight polyol and a polyisocyanate compound. The low-molecular-weight polyol may be the same as the polyhydric alcohol exemplified as the raw material for the polyester polyol. The high-molecular-weight polyol may be a polyether polyol, a polyester polyol, or the like. The polyisocyanate compound may be the same as the polyisocyanate used in the urethane prepolymer (A1).

[0109] Examples of the vegetable oil polyol include castor oil, dehydrated castor oil, hardened castor oil which is a hydrogenated castor oil, and an adduct of castor oil with 5 to 50 moles of alkylene oxide.

[0110] Examples of the sugar alcohol include pentaerythritol, sucrose, xylitol, sorbitol, isomalt, lactitol, maltitol, and mannitol.

[0111] When the two-component curing adhesive is used as a solventless adhesive, the viscosity of the polyol composition (Y) is adjusted to a range suitable for the non-solvent lamination method. For example, the viscosity at 40°C is adjusted to 100 to 5000 mPas, more preferably 100 to 3000 mPas. The viscosity of the polyol composition (Y) can be adjusted by the skeleton of the polyol compound or the plasticizer described below. When adjusting the skeleton of the polyol compound, the viscosity can be reduced by using, for example, polypropylene glycol or a polyester polyol obtained by reacting an aliphatic carboxylic acid with a polyol. Alternatively, the viscosity can be increased by using a polyester polyol obtained by reacting an aromatic carboxylic acid with a polyol.

[0112] It is preferable to use a composition containing a polyester skeleton as either or both of the polyisocyanate composition (X) and the polyol composition (Y) in the two-component curing adhesive, since this allows for the production of a packaging material with even better retort resistance.

[0113] (Other Components of the Adhesive) The two-component curing adhesive may contain components other than those described above. The other components may be contained in either or both of the polyisocyanate composition (X) and the polyol composition (Y), or may be prepared separately from these and mixed with the polyisocyanate composition (X) and the polyol composition (Y) immediately before application of the adhesive. Each component will be described below.

[0114] (Polyamine (C)) The polyol composition (Y) may contain a polyamine (C) having a plurality of amino groups. In this specification, the amino group refers to a group such as NH ２ group or NHR group (R is an alkyl group or aryl group which may have a functional group).

[0115] As the polyamine (C), known polyamines can be used without any particular limitation, and examples thereof include methylenediamine, ethylenediamine, isophoronediamine, 3,9-dipropanamine-2,4,8,10-tetraoxaspirodoundecane, lysine, 2,2,4-trimethylhexamethylenediamine, hydrazine, piperazine, 2-hydroxyethylethylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, poly(propylene glycol)diamine, poly(propylene glycol)triamine, poly(propylene glycol)tetraamine, 1,2-diaminopropane, 1,3-diaminopropane,

[0116] 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine, nonaethylenedecamine, trimethylhexamethylenediamine, tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, triethylene-bis(trimethylene)hexamine, bis(3-aminoethyl)amine, bishexamethylenetriamine, 1,4-cyclohexanediamine, 4,4'-methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, norbornadiamine,

[0117] Amine compounds (C1) having multiple amino groups, such as bis(aminomethyl)cyclohexane, diaminodicyclohexylmethane, isophoronediamine, menthenediamine, bis(cyanoethyl)diethylenetriamine, 1,4-bis-(8-aminopropyl)-piperazine, piperazine-1,4-diazacycloheptane, 1-(2'-aminoethylpiperazine), 1-[2'-(2"-aminoethylamino)ethyl]piperazine, tricyclodecanediamine, and polyureaamines which are reaction products of the above-mentioned various polyamines with the above-mentioned various isocyanate components.

[0118] Primary or secondary alkanolamines (C2) such as monoethanolamine, monoisopropanolamine, monobutanolamine, N-methylethanolamine, N-ethylethanolamine, N-methylpropanolamine, diethanolamine, and diisopropanolamine

[0119] Examples thereof include primary or secondary amines (C3) such as ethylamine, octylamine, laurylamine, myristylamine, stearylamine, oleylamine, diethylamine, dibutylamine, and distearylamine.

[0120] The amount of the polyamine (C) to be blended is preferably such that the amine value of the polyol composition (Y) is 20 to 70 mgKOH / g, more preferably 25 to 50 mgKOH / g.

[0121] The amine value in this specification refers to the number of milligrams of KOH equivalent to the amount of HCl required to neutralize 1 g of sample, and is not particularly limited and can be calculated using known methods. When the chemical structure of the amine compound (C) and, if necessary, the average molecular weight, etc. are known, the amine value can be calculated from (number of amino groups per molecule / average molecular weight) x 56.1 x 1000. When the chemical structure, average molecular weight, etc. of the amine compound are unknown, the amine value can be measured according to known amine value measurement methods, for example, JIS K7237-1995.

[0122] (Monool Compound (D)) The polyol composition (Y) may contain a monool compound (D) having one alcoholic hydroxyl group. The main chain of the monool compound (D) is not particularly limited, and examples thereof include vinyl resins, acrylic resins, polyesters, epoxy resins, and urethane resins having one hydroxyl group. Aliphatic alcohols, alkyl alkylene glycols, and the like can also be used. The main chain of the monool compound (D) may be linear or branched. The bonding position of the hydroxyl group is not particularly limited, but it is preferably present at the terminal of the molecular chain.

[0123] Specific examples of the monool compound (D) include aliphatic monools such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, lauryl alcohol, myristyl alcohol, pentadecanol, cetyl alcohol, heptadecanol, stearyl alcohol, nonadecanol, other alkanols (C20 to C50), oleyl alcohol, and isomers thereof;

[0124] Cyclohexanol, methylcyclohexanol, 4-butylcyclohexanol, 4-pentylcyclohexanol, 4-hexylcyclohexanol, cyclodecanol, cyclododecanol, cyclopentadecanol, 4-isopropylcyclohexanol, 3,5,5-trimethylcyclohexanol, menthol, 2-norbornanol, borneol, 2-adamantanol, dicyclohexylmethanol, decitol, 2-cyclohexylcyclohexanol, 4-cyclohexylcyclohexanol, 4-(4-propylcyclohexyl)cyclohexanol, 4-(4-pentylcyclohexyl)cyclohexanol alicyclic monools such as cyclohexanol, α-ambrinol, desoxycorticosterone, 11-dehydrocorticosterone, cholesterol, β-sitosterol, campesterol, stigmasterol, brassicasterol, lanosterol, ergosterol, β-cholestanol, testosterone, estrone, digitoxigenin, dehydroepiandrosterone, coprostanol, pregnenolone, epicholestanol, 7-dehydrocholesterol, estradiol benzoate, tigogenin, hecogenin, methandienone, cortisone acetate, stenolone, and isomers thereof;

[0125] aromatic aliphatic monools such as benzyl alcohol,

[0126] Examples of the polyoxyalkylene monool include polyoxyalkylene monools obtained by ring-opening addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using an alkyl compound containing one active hydrogen as an initiator.

[0127] (Catalyst) Examples of the catalyst include metal catalysts, amine catalysts, and aliphatic cyclic amide compounds.

[0128] The metal catalyst may be a metal complex catalyst, an inorganic metal catalyst, or an organic metal catalyst. Examples of the metal complex catalyst 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.

[0129] The inorganic metal catalyst may be selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, and the like.

[0130] 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; titanium compounds such as tetraisopropyloxytitanate, dibutyltitanium dichloride, tetrabutyltitanium, butoxytitanium trichloride, aliphatic diketones, aromatic diketones, and titanium chelate complexes having at least one alcohol having 2 to 10 carbon atoms as a ligand.

[0131] 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)iso 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.

[0132] 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.

[0133] (Acid anhydride) Examples of the acid anhydride include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, unsaturated carboxylic acid anhydrides, etc., and can be used alone or in combination of two or more.More specifically, for example, phthalic acid anhydride, trimellitic acid anhydride, pyromellitic acid anhydride, benzophenonetetracarboxylic acid anhydride, dodecenylsuccinic acid anhydride, polyadipic acid anhydride, polyazelaic acid anhydride, polysebacic acid anhydride, poly(ethyloctadecanedioic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, tetrahydrophthalic acid anhydride, methyltetrahydrophthalic acid anhydride, methylhexahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, methylhimic acid anhydride, trialkyltetrahydrophthalic acid anhydride, Examples of such an anhydride include methylcyclohexene dicarboxylic acid anhydride, methylcyclohexene tetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, HET anhydride, Nadic anhydride, methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid dianhydride, and 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid dianhydride.

[0134] Alternatively, the acid anhydride may be a compound modified with a glycol. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; and polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Furthermore, copolymer polyether glycols of two or more of these glycols and / or polyether glycols may also be used.

[0135] (Coupling Agent) Examples of the coupling agent include silane coupling agents, titanate-based coupling agents, and aluminum-based coupling agents.

[0136] 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.

[0137] 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.

[0138] Examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate.

[0139] (Pigment) The pigment is not particularly limited, and examples thereof include organic pigments and inorganic pigments such as extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearlescent pigments listed in the Paint Raw Materials Handbook 1970 Edition (compiled by the Japan Paint Manufacturers Association), as well as plastic pigments.

[0140] Examples of the extender pigment include precipitated barium sulfate, powdered barium sulfate, precipitated calcium carbonate, calcium bicarbonate, kansui stone, alumina white, silica, hydrous fine powdered silica (white carbon), ultrafine powdered anhydrous silica (aerosil), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and yellow ochre.

[0141] Specific examples of the organic pigments include various insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, and Lake 4R; soluble azo pigments such as Lake C, Carmine 6B, and Bordeaux 10; various (copper) phthalocyanine pigments such as Phthalocyanine Blue and Phthalocyanine Green; various chlorine dyeing lakes such as Rhodamine Lake and Methyl Violet Lake; various mordant dye pigments such as Quinoline Lake and Fast Sky Blue; various vat dye pigments such as Anthraquinone pigments, Thioindigo pigments, and Perinone pigments; various quinacridone pigments such as Synchasia Red B; various dioxazine pigments such as Dioxazine Violet; various condensed azo pigments such as Chromophtal; and aniline black.

[0142] Examples of the inorganic pigments include various chromates such as yellow lead, zinc chromate, and molybdate orange; various ferrocyanide compounds such as iron blue; various metal oxides such as titanium oxide, zinc white, mapico yellow, iron oxide, red iron oxide, chrome oxide green, and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red, and mercury sulfide; various sulfates such as barium sulfate and lead sulfate; various silicates such as calcium silicate and ultramarine; various carbonates such as calcium carbonate and magnesium carbonate; various phosphates such as cobalt violet and manganese purple; various metal powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, and brass powder; flake pigments of these metals, mica flake pigments; metallic pigments and pearl pigments such as mica flake pigments coated with metal oxides and micaceous iron oxide pigments; graphite, carbon black, and the like.

[0143] Examples of the plastic pigment include "Grandol PP-1000" and "PP-2000S" manufactured by DIC Corporation.

[0144] The pigment to be used may be selected appropriately depending on the purpose. For example, inorganic oxides such as titanium oxide and zinc oxide are preferably used as white pigments because they have excellent durability, weather resistance, and design properties, and carbon black is preferably used as black pigments.

[0145] The blending amount of the pigment is, for example, 1 to 400 parts by mass per 100 parts by mass of the total amount of nonvolatile components of the polyol composition (X) and the polyisocyanate composition (Y), and is more preferably 10 to 300 parts by mass in order to improve adhesion and blocking resistance.

[0146] (Plasticizer) Examples of the plasticizer include phthalic acid-based plasticizers, fatty acid-based plasticizers, aromatic polycarboxylic acid-based plasticizers, phosphoric acid-based plasticizers, polyol-based plasticizers, epoxy-based plasticizers, polyester-based plasticizers, and carbonate-based plasticizers.

[0147] Examples of the phthalic acid plasticizer include phthalic acid ester plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di-(2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, dilauryl phthalate, distearyl phthalate, diphenyl phthalate, dibenzyl phthalate, butylbenzyl phthalate, dicyclohexyl phthalate, octyldecyl phthalate, dimethyl isophthalate, di-(2-ethylhexyl) isophthalate, and diisooctyl isophthalate; and tetrahydrophthalic acid ester plasticizers such as di-(2-ethylhexyl) tetrahydrophthalate, di-n-octyl tetrahydrophthalate, and diisodecyl tetrahydrophthalate.

[0148] Examples of the fatty acid plasticizer include adipic acid plasticizers such as di-n-butyl adipate, di-(2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di(C6-C10 alkyl) adipate, and dibutyl diglycol adipate; azelaic acid plasticizers such as di-n-hexyl azelate, di-(2-ethylhexyl) azelate, and diisooctyl azelate; and di-n-butyl sebacate and diisooctyl azelate. Sebacic acid plasticizers such as di-(2-ethylhexyl) sebacate and diisononyl sebacate; maleic acid plasticizers such as dimethyl maleate, diethyl maleate, di-n-butyl maleate and di-(2-ethylhexyl) maleate; fumaric acid plasticizers such as di-n-butyl fumarate and di-(2-ethylhexyl) fumarate; monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate and di Examples of suitable plasticizers include itaconic acid-based plasticizers such as butyl itaconate and di-(2-ethylhexyl) itaconate; stearic acid-based plasticizers such as n-butyl stearate, glycerin monostearate, and diethylene glycol distearate; oleic acid-based plasticizers such as butyl oleate, glyceryl monooleate, and diethylene glycol monooleate; citric acid-based plasticizers such as triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, and acetyl tri-(2-ethylhexyl) citrate; ricinoleic acid-based plasticizers such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, glyceryl monoricinoleate, and diethylene glycol monoricinoleate; and other fatty acid-based plasticizers such as diethylene glycol monolaurate, diethylene glycol dipelargonate, and pentaerythritol fatty acid esters.

[0149] Examples of the aromatic polycarboxylic acid plasticizer include trimellitic acid plasticizers such as tri-n-hexyl trimellitate, tri-(2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, triisononyl trimellitate, tridecyl trimellitate, and triisodecyl trimellitate; and pyromellitic acid plasticizers such as tetra-(2-ethylhexyl) pyromellitate and tetra-n-octyl pyromellitate.

[0150] Examples of the phosphoric acid plasticizer include triethyl phosphate, tributyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, cresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(chloroethyl) phosphate, tris(chloropropyl) phosphate, tris(dichloropropyl) phosphate, and tris(isopropylphenyl) phosphate.

[0151] Examples of the polyol-based plasticizer include glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di-(2-ethylbutyrate), triethylene glycol di-(2-ethylhexoate), and dibutylmethylene bisthioglycolate; and glycerin-based plasticizers such as glycerol monoacetate, glycerol triacetate, and glycerol tributyrate.

[0152] Examples of the epoxy plasticizer include epoxidized soybean oil, epoxy butyl stearate, di-2-ethylhexyl epoxy hexahydrophthalate, diisodecyl epoxy hexahydrophthalate, epoxy triglyceride, epoxidized octyl oleate, and epoxidized decyl oleate.

[0153] Examples of the polyester plasticizer include adipic acid polyesters, sebacic acid polyesters, and phthalic acid polyesters.

[0154] Examples of the carbonate plasticizer include propylene carbonate and ethylene carbonate.

[0155] Other examples of the plasticizer include partially hydrogenated terphenyls, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate, acrylic monomers and oligomers, etc. These plasticizers can be used alone or in combination of two or more.

[0156] (Phosphate Compound) Examples of the phosphoric acid compound (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.

[0157] (Form of adhesive) The two-component curing adhesive may be either a solvent-based or solventless type. In this specification, a "solvent-based" adhesive refers to a form used in a so-called dry lamination 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, and then bonded to another substrate. Either or both of the polyisocyanate composition (X) and the polyol composition (Y) contain an organic solvent capable of dissolving (diluting) the components of the polyisocyanate composition (X) and the polyol composition (Y).

[0158] Examples of the organic solvent include esters such as ethyl acetate, butyl acetate, cellosolve acetate, etc., ketones such as acetone, methyl ethyl ketone, isobutyl ketone, cyclohexanone, etc., ethers such as tetrahydrofuran, dioxane, etc., aromatic hydrocarbons such as toluene, xylene, etc., halogenated hydrocarbons such as methylene chloride, ethylene chloride, etc., dimethyl sulfoxide, dimethyl sulfamide, etc. The organic solvent used as a reaction medium during production of the components of the polyisocyanate composition (X) and the polyol composition (Y) may also be used as a diluent during coating.

[0159] In this specification, a "solventless" adhesive refers to a form of adhesive in which the polyisocyanate composition (X) and the polyol composition (Y) are substantially free of esters such as ethyl acetate, butyl acetate, cellosolve acetate, etc.; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, cyclohexanone, etc.; ethers such as tetrahydrofuran, dioxane, etc.; aromatic hydrocarbons such as toluene, xylene, etc.; halogenated hydrocarbons such as methylene chloride, ethylene chloride, etc.; highly soluble organic solvents such as dimethyl sulfoxide, dimethyl sulfamide, in particular ethyl acetate or methyl ethyl ketone; and which is used in a method in which the adhesive is applied to a substrate and then bonded to another substrate without going through a step of heating in an oven or the like to volatilize the solvent, i.e., a so-called non-solvent lamination method. If the organic solvent used as a reaction medium during the production of the components of the polyisocyanate composition (X) or the polyol composition (Y) or the raw materials thereof cannot be completely removed, and trace amounts of organic solvent remain in the polyisocyanate composition (X) or the polyol composition (Y), the composition is considered to be substantially free of organic solvent. Furthermore, if the polyol composition (Y) contains a low-molecular-weight alcohol, the low-molecular-weight alcohol reacts with the polyisocyanate composition (X) to become part of the coating film, and therefore does not need to be volatilized after application. Therefore, such a form is also treated as a solventless adhesive, and the low-molecular-weight alcohol is not considered an organic solvent.

[0160] The two-component curing adhesive is preferably used by blending the polyisocyanate composition (X) with the polyol composition (Y) so that the ratio [NCO] / [OH], where [NCO] is the number of moles of isocyanate groups in the polyisocyanate composition (X) and [OH] is the number of moles of hydroxyl groups in the polyol composition (Y), is 1.0 to 3.0. This allows for appropriate curing properties to be obtained without depending on the environmental humidity at the time of application.

[0161] The two-component curing adhesive may be a commercially available product, such as DIC Graphics Corporation's DIC Dry LX-500 / KW-75, DIC Dry LX-520 / KO40, DIC Dry LX-703VL / KR-90, DIC Dry LX-732 / KVM-90, DIC Dry LX-906 / KO55, and DIC Dry LX-9 63 / KO-40, Dick Dry LX-901 / KW-75, etc., manufactured by Toyo Ink Co., Ltd., TM-250HV / CAT-RT86, TM-595 / CAT-56, TM-265L / CAT-RT37, AD-502 / CAT-10, AD-556 / CAT-56, AD-811 / CAT-RT8, AD-817 / CAT-RT56, AD-900 / CAT T-RT85, etc., Takelac A-310 / Takenate A-3, Takelac A-315 / Takenate A-10, Takelac A-385 / Takenate A-50, Takelac A-515 / Takenate A-50, Takelac A-520 / Takenate A-50, Takelac A-525 / Takenate A-52, Takelac A-606 / Takenate manufactured by Mitsui Chemicals, Inc. Examples of the polyether adhesive / curing agent combination include Takelac A-10, Takelac A-620 / Takenate A-65, Takelac A-626 / Takenate A-50, Takelac A-627 / Takenate A-65, Takelac A-975 / Takenate A-3, and Seikabond E-366 / C-83, E-370 / C-84, E-372 / C-76, and A601 / C84 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. Examples of the polyether adhesive / curing agent combination include DIC Dry LX-401A / SP-60 and DIC Dry LE-3100 / SL-75 manufactured by DIC Graphics Corporation, and Seikabond A-159 / C-89F manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. Examples of polyurethane adhesives include one-component moisture-curing polyurethane resins (trade name: Unoflex series) and two-component curing polyurethane resins (trade name: Polybond series) manufactured by Sanyo Chemical Industries, Ltd.

[0162] (Biomass adhesive) In the two-component curing adhesive, in consideration of the establishment of a recycling-oriented society that should develop sustainably (sustainability), it is preferable to use plant-derived raw materials as raw materials for the polyisocyanate composition (X) or the polyol composition (Y).

[0163] The biomass content can be increased by appropriately using biomass raw materials as raw materials for the two-component curing adhesive. Examples of biomass raw materials include castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil (a hydrogenated castor oil), and 5-50 mol alkylene oxide adducts of castor oil; aliphatic polybasic acids such as succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, and itaconic acid; alkyl esters of these acids; and dimer acids.

[0164] Commercially available biomass adhesives may be used, such as adhesives listed in the Japan Organics Resources Association, including, for example, DIC Dry BM (manufactured by DIC Corporation) and Takenate BM (manufactured by Mitsui Chemicals, Inc.).

[0165] The weight of the adhesive layer after drying is 0.1 to 10 g / m ２ It is preferable that the density is 1 to 6 g / m ２ More preferably, it is 2 to 5 g / m ２ It is more preferable that:

[0166] The thickness of the adhesive layer is preferably 0.1 to 10 μm, more preferably 1 to 7 μm, and even more preferably 2 to 5 μm.

[0167] A functional adhesive may be used as the adhesive. For example, an adhesive having gas barrier properties may be used, such as the oxygen barrier adhesive PASLIM series manufactured by DIC Corporation, which is a two-component, two-component curing adhesive made of polyester polyol and an isocyanate compound. After the gas barrier adhesive is cured or dried, it becomes a gas barrier adhesive layer. Use of a gas barrier adhesive is preferred because it can further enhance the gas barrier properties of the laminate of the present invention.

[0168] Various types of pressure-sensitive adhesives can also be used as the adhesive, and it is preferable to use a pressure-sensitive adhesive. Examples of pressure-sensitive adhesives include rubber-based pressure-sensitive adhesives obtained by dissolving polyisobutylene rubber, butyl rubber, or mixtures thereof in organic solvents such as benzene, toluene, xylene, and hexane, or these rubber-based pressure-sensitive adhesives blended with tackifiers such as abiethylene acid rosin ester, terpene-phenol copolymer, and terpene-indene copolymer, and acrylic-based pressure-sensitive adhesives obtained by dissolving an acrylic copolymer having a glass transition temperature of −20° C. or lower, such as a 2-ethylhexyl acrylate-n-butyl acrylate copolymer or a 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer, in an organic solvent.

[0169] The adhesive can be applied by, for example, direct gravure roll coating, gravure offset roll coating, kiss coating, reverse roll coating, Fountain coating, transfer roll coating, or other methods.

[0170] 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.

[0171] 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.

[0172] 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 less ２ 5g / m or more ２In 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.

[0173] (Thermoplastic Resin) The adhesive layer can also be formed from a thermoplastic resin, and the formation method thereof can be a conventionally known method, for example, extrusion lamination or sand lamination. Examples of the thermoplastic resin that can be used for the adhesive layer include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE); polypropylene resins such as propylene homopolymers, propylene-α-olefin random copolymers, and propylene-α-olefin block copolymers; norbornene polymers and hydrogenated products thereof, such as norbornene copolymers (COC) obtained by copolymerizing norbornene monomers with olefins such as ethylene; vinyl alicyclic hydrocarbon polymers; and cyclic polyolefin resins such as cyclic conjugated diene polymers. Examples of suitable elastomers include polyethylene-based elastomers such as ethylene-vinyl acetate copolymer (EVA) and ethylene-α-olefin copolymers, polypropylene-based elastomers, and butene-based elastomers; ethylene-based copolymers such as 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. Furthermore, in order to improve interlayer adhesion, acid-modified polyolefin-based resins obtained by modifying the above-mentioned polyolefin-based resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used. In addition, resins obtained by graft polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers with polyolefin resins can also be used. These resins can be used alone or in combination of two or more. It is also preferable to use polyethylene-based resins that use biomass-derived ethylene as a monomer unit.

[0174] When the adhesive layer is laminated by extrusion lamination, an anchor coating layer may be formed by applying and drying an anchor coating agent to the surface of the layer to be laminated. Examples of anchor coating agents include anchor coating agents made of any resin with a heat resistance temperature of 135°C or higher, such as polybutadiene-based resins, urethane resins, polyisocyanate-polyether polyols, polyethyleneimine, vinyl-modified resins, epoxy resins, polyester resins, and alkyl titanates, as well as anchor coating agents obtained by diluting the above adhesives with organic solvents. Among these, polyethyleneimine-based anchor coating agents and anchor coating agents obtained by diluting the above adhesives with organic solvents are preferred. A silane coupling agent may also be used as an additive, and soluble nitrocellulose may also be used to enhance heat resistance.

[0175] When the sealant film of the present invention is laminated with a substrate or the like by extrusion lamination or sand lamination to obtain the laminate of the present invention, the nip roll or chill roll used during lamination may be replaced with an embossing roll to emboss the surface of the seal layer side.

[0176] (Printed Layer) The printed layer is a layer on which characters, figures, symbols, and other desired designs are printed. The printing method and printing ink are not particularly limited, and known printing methods and printing inks can be used. Printing inks using methods such as gravure printing, flexographic printing, lithographic offset printing, and inkjet recording printing are often used for the films used as the above-mentioned substrates. Printing inks that combine these printing methods with methods of curing using active energy rays such as ultraviolet (UV), LED, and electron beam (EB), or methods of curing using heat, are also used. Depending on the solvent used, inks may be referred to as water-based inks or organic solvent-based inks.

[0177] Specific examples include gravure printing ink and flexographic printing ink (in some industries, gravure printing ink and flexographic printing ink are sometimes referred to as liquid printing ink), ultraviolet-curable ink for lithographic offset printing, electron-beam-curable ink for lithographic offset printing, ultraviolet-curable ink for inkjet recording and printing, and electron-beam-curable ink for inkjet recording and printing.

[0178] The position of the printed layer printed using these inks is arbitrary, and it may be provided on the substrate, or a substrate on which a separate printed layer is provided may be one of the constituent components of the laminate of the present invention, and the position is arbitrary. The ink may contain a resin, a colorant, and a solvent as essential components, or it may be a so-called clear ink that contains a resin and a solvent but does not substantially contain a colorant. Below, we will explain liquid printing inks containing a polyurethane resin and a colorant, which are most commonly used for printing on laminate films.

[0179] (Liquid Printing Ink) The liquid printing ink to be printed on the printing layer of the present invention contains a polyurethane resin and a colorant. The liquid printing ink is preferably a liquid printing ink containing one or more polyurethane resins formed from polyester polyol and polyisocyanate.

[0180] (Polyurethane Resin) The liquid printing ink contains a polyurethane resin obtained by polymerizing a polyol and a polyisocyanate. The polyol is preferably a polyester polyol. If necessary, the polyurethane resin may be synthesized by using a general-purpose polyol other than polyether polyol, polyester polyol, or polyether polyol, a chain extender, or a terminal blocking agent in combination. Furthermore, the polyol may be reacted with a polyisocyanate to form a urethane prepolymer having an isocyanate group at its terminal, and the resulting urethane prepolymer may be reacted with a polyamine compound to synthesize the polyurethane resin. The polyurethane resin may be used alone or in combination in the liquid printing ink.

[0181] The glass transition temperature of the polyurethane resin is preferably −60° C. or higher, more preferably −50° C. or higher, and is preferably lower than 0° C., more preferably lower than −30° C.

[0182] (Polyester Polyol) The polyester polyol, which is a reaction raw material for the polyurethane resin used in the liquid printing ink, is obtained by reacting a polycarboxylic acid having two or more carboxyl groups with a polyol having two or more hydroxyl groups.

[0183] (Polycarboxylic Acid) Examples of the polycarboxylic acid include dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dimer acid, and acid anhydrides thereof; tricarboxylic acids such as trimellitic acid and its anhydrides; benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid, and anhydrides of these acids.

[0184] These polycarboxylic acids may be used alone or in combination. Examples of polycarboxylic acids used in combination include azelaic acid, pimelic acid, malonic acid, etc., combined with succinic acid, sebacic acid, suberic acid, and adipic acid, which are preferred because they improve laminate strength and heat resistance. Furthermore, the use of succinic acid, succinic anhydride, and adipic acid in combination with sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, trimellitic acid, and pyromellitic acid is preferred because it can achieve both adhesion to a wide variety of films, blocking resistance, and high laminate strength.

[0185] The polycarboxylic acid may be derived from a plant. The use of a plant-derived polycarboxylic acid is preferred because it increases the biomass content of the liquid printing ink. Specific examples of the plant-derived polycarboxylic acid include succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, and malic acid.

[0186] (Polyol) Examples of the polyol include glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-butynediol, and 1,4-butylenediol; 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, and 2-butylenediol; Examples of suitable branched glycols include 2-ethyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, and 2-methyl-1,8-octanediol; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol, 1,2,6-hexanetriol, and 1,2,4-butanetriol. These compounds may be used alone or in combination of two or more.

[0187] Plant-derived raw materials can also be used as the polyol. Using plant-derived polyols is preferable because it increases the biomass content of the liquid printing ink. Specific examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, pentylene glycol, 1,10-dodecanediol, dimer diol, and isosorbide.

[0188] The polyester polyol is preferably contained in an amount of 30 to 95% by mass, more preferably 40 to 90% by mass, and most preferably 45 to 85% by mass, based on the total amount of the polyurethane resin.

[0189] The number average molecular weight of the polyester polyol is preferably in the range of 400 to 10,000, more preferably in the range of 500 to 7,000, even more preferably in the range of 800 to 6,000, more preferably in the range of 1,000 to 6,000, and even more preferably in the range of 1,500 to 5,500. In the present invention, the number average and weight average molecular weights are values ​​measured by gel permeation chromatography (GPC) under the following conditions:

[0190] (GPC Measurement) Measuring apparatus: High-speed GPC apparatus ("HLC-8220GPC" manufactured by Tosoh Corporation) Column: The following columns manufactured by Tosoh Corporation were connected in series and used: "TSKgel G5000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G4000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G3000" (7.8 mm I.D. x 30 cm) x 1, "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1 Detector: RI (differential refractometer) Column temperature: 40°C Eluent: tetrahydrofuran (THF) Flow rate: 1.0 mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass) Standard sample: A calibration curve was prepared using the following standard polystyrene.

[0191] [Standard polystyrene] "TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation "TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation "TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation "TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation "TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0192] (Polyether Polyol) Furthermore, it is more preferable for the polyurethane resin to contain a polyether polyol in a range of 1 to 40% by mass relative to the polyurethane resin as a constituent component. Various known polyether polyols commonly used in the production of polyurethane resins can be used as the polyether polyol, and one or more of these may be used in combination. Examples include polyether polyols of polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, etc. When the polyether polyol content is 1% by mass or more relative to the polyurethane resin, the polyurethane resin exhibits good solubility in ketone, ester, and alcohol-based solvents, and the resolubility of the ink film in these solvents is less likely to decrease, resulting in less deterioration of the tone reproducibility of printed matter. Furthermore, when the content is 40% by mass or less, blocking resistance is less likely to decrease. It is particularly preferable to contain the polyether polyol in a range of 1 to 30% by mass relative to the polyurethane resin, and most preferably in a range of 1 to 20% by mass.

[0193] Furthermore, the number-average molecular weight of the polyether polyol is more preferably 100 to 4,000. When the number-average molecular weight of the polyether polyol is 100 or more, the polyurethane resin film does not harden and adhesion to the polyester film is less likely to decrease. When the number-average molecular weight is 4,000 or less, the polyurethane resin film has sufficient strength and the blocking resistance of the ink film tends to be less likely to decrease.

[0194] Specific examples of the polyether polyol include bifunctional alcohols (glycols) such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol; trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, and pentaerythritol; and bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F.

[0195] Examples of the polyether polyol include polytetramethylene glycol, polypropylene glycol, polyethylene glycol, polytrimethylene glycol, and the like, which are obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as the above-mentioned glycols, trifunctional or tetrafunctional aliphatic alcohols, and the like; and polyether urethane polyols obtained by further increasing the molecular weight of such polyether polyols with the above-mentioned aromatic or aliphatic polyisocyanates.

[0196] (General-Purpose Polyol) In synthesizing the polyurethane resin used in the liquid printing ink, a general-purpose polyol may be used in combination, if necessary. As the general-purpose polyol, various known polyols generally used in the production of polyurethane resins can be used, and one or more of them may be used in combination. For example, glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, and 2-butyl-2-ethyl glycols having a branched structure such as 1,3-propanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, and 2-methyl-1,8-octanediol; low molecular weight polyols such as glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, and sorbitol;

[0197] Polyether polyols of polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, etc.; polyester polyols obtained by dehydration condensation or polymerization of the above low molecular weight polyols with petroleum-derived polycarboxylic acids such as sebacic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, trimellitic acid, pyromellitic acid, etc., or anhydrides thereof; polyester polyols obtained by ring-opening polymerization of cyclic ester compounds, for example, lactones such as polycaprolactone, polyvalerolactone, poly(β-methyl-γ-valerolactone); Examples of suitable polyols include polycarbonate polyols obtained by reacting polyols or the like with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc.; polybutadiene glycols; glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A; acrylic polyols, castor oil polyols, hydrogenated castor oil polyols, dimer diols, and hydrogenated dimer diols obtained by copolymerizing, in one molecule, one or more hydroxyethyl groups, hydroxypropyl acrylate, hydroxybutyl acrylate, etc., or their corresponding methacrylic acid derivatives, with, for example, acrylic acid, methacrylic acid, or an ester thereof.

[0198] Plant-derived raw materials can also be used as the general-purpose polyol. Using plant-derived polyols is preferable because it increases the biomass content of the liquid printing ink. Specific examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, pentylene glycol, 1,10-dodecanediol, dimer diol, and isosorbide.

[0199] (Polyisocyanate) The polyisocyanate used in the polyurethane resin in the liquid printing ink is preferably a diisocyanate compound, and examples thereof include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates that are generally used in the production of polyurethane resins. For example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, Aromatic polyisocyanates such as zene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-diisocyanate, biphenyl-4,4'-diisocyanate, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, and diphenylmethane-2,4-diisocyanate;Aliphatic or alicyclic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di(isocyanatomethyl)cyclohexane, 1,4-di(isocyanatomethyl)cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate can be used. These polyisocyanates can be used alone or in combination of two or more. Among these, it is preferable to use an aliphatic polyisocyanate and / or an alicyclic polyisocyanate, since appropriate flexibility can be obtained, and it is more preferable to use isophorone diisocyanate or hexamethylene diisocyanate, since adhesive strength can be further improved.

[0200] The polyisocyanate may be derived from a plant. The use of a plant-derived polyisocyanate is preferred because it increases the biomass content of the liquid printing ink. Specific examples include 1,5-pentamethylene diisocyanate and dimer diisocyanate.

[0201] (Other Components of Polyurethane Resin) Examples of chain extenders used in the polyurethane resin in the liquid printing ink include diamine compounds such as ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, diethylenetriamine, triethylenetetratriamine, toluylenediamine, and xylenediamine, as well as amines having a hydroxyl group in the molecule such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. These chain extenders can be used alone or in combination of two or more.

[0202] Further examples of reaction terminators include polyamine compounds, dialkylamines such as di-n-butylamine, and alcohols such as ethanol and isopropyl alcohol. Using a polyamine compound as a reaction terminator is preferred because it can increase the pigment concentration of the ink due to its pigment dispersion effect. Preferred polyamine compounds include those having either a primary amino group or a secondary amino group at the terminal, such as ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, diethylenetriamine, triethylenetetratriamine, toluylenediamine, xylenediamine, N-(2-hydroxyethyl)ethylenediamine, and N-(2-hydroxyethyl)propyleneamine. Furthermore, when introducing carboxyl groups into a polyurethane resin, amino acids such as glycine and L-alanine can be used as reaction terminators. These end-capping agents can be used alone or in combination.

[0203] (Synthesis of Polyurethane Resin) The polyurethane resin used in the liquid printing ink is obtained by reacting various polyols, polyisocyanates, chain extenders, and, if necessary, end-capping agents. For example, the polyester polyol may be reacted with the polyester polyol, and optionally the polyether polyol and a general-purpose polyol, and the polyisocyanate in a proportion such that the isocyanate groups are in excess to obtain a prepolymer having terminal isocyanate groups. The resulting prepolymer may then be reacted with a chain extender and / or a terminal blocking agent in a suitable solvent, such as an ester solvent commonly used as a solvent for liquid printing inks, such as ethyl acetate, propyl acetate, or butyl acetate; a ketone solvent such as acetone, methyl ethyl ketone, or methyl isobutyl ketone; an alcohol solvent such as methanol, ethanol, isopropyl alcohol, or n-butanol; or a hydrocarbon solvent such as toluene, xylene, methylcyclohexane, or ethylcyclohexane, or a mixture thereof; or a single-stage method may be used in which the polyester polyol and polyisocyanate, and optionally the polyether polyol and a general-purpose polyol, and the chain extender and / or terminal blocking agent are reacted all at once in a suitable organic solvent selected from the above.

[0204] The weight-average molecular weight of the polyurethane resin is preferably within the range of 10,000 to 100,000. If the weight-average molecular weight of the polyurethane resin is 10,000 or more, the blocking resistance of the resulting ink, the strength and oil resistance of the printed film, etc. are less likely to decrease, and sufficient laminate strength can be obtained. If it is 100,000 or less, the viscosity of the resulting ink does not become too high, and the gloss of the printed film is easily maintained. The weight-average molecular weight of the polyurethane resin is a value obtained by measuring it in the same manner as the number-average molecular weight of the polyester polyol.

[0205] The content of the polyurethane resin relative to the total amount of the ink is preferably 3% by mass or more of the total amount of the composition from the viewpoint of ensuring sufficient adhesion of the ink to the substrate, and 25% by mass or less from the viewpoint of appropriate ink viscosity and work efficiency during ink production and printing, and more preferably in the range of 5 to 15% by mass. When polyurethane resins are used in combination in the liquid printing ink, the total content ratio of the polyurethane resins relative to the total amount of the ink is preferably 3 to 25% by mass or less, and more preferably in the range of 5 to 15% by mass.

[0206] (Other Resins in Liquid Printing Ink) The liquid printing ink may contain resins other than polyurethane resins. Examples of such resins other than polyurethane resins include general-purpose resins commonly used in gravure inks or flexographic inks. Specific examples include vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-acrylic copolymer resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, polyamide resins, acrylic resins, polyester resins, alkyd resins, polyvinyl chloride resins, rosin-based resins, rosin-modified maleic acid resins, ketone resins, cyclized rubbers, chlorinated rubbers, butyral, and petroleum resins. These resins that can be used in combination can be used alone or in combination of two or more. The content of the resins that can be used in combination is preferably 0.5 to 25% by mass, more preferably 1 to 15% by mass, based on the total mass of the ink.

[0207] (Curing Agent) The urethane resin may be used in combination with a curing agent. A curing agent generally used in organic solvent-based gravure printing inks may be used as the curing agent, but the most commonly used curing agent is an isocyanate-based curing agent. From the standpoint of curing efficiency, the amount of the isocyanate compound added is preferably in the range of 0.3% by mass to 10.0% by mass, and more preferably 1.0% by mass to 7.0% by mass, based on the solid content of the liquid printing ink.

[0208] (Organic Solvent) The organic solvent used in the liquid printing ink is not particularly limited, and any known organic solvent can be used. Generally, ethyl acetate, propyl acetate, isopropanol, normal propanol, etc. are often used in view of both the hygiene during printing and the harmfulness of packaging materials.

[0209] Water may be added to the liquid printing ink as a volatile component along with the organic solvent. The addition of water can control the drying properties of the ink, particularly in gravure printing, allowing for a clear reproduction of the gradation areas characterized by low ink transfer. The amount of water added is preferably in the range of 0.3 to 10% by mass of the total liquid printing ink to ensure good printability. Adding 0.3% by mass or more of water tends to improve the reproduction of gradation areas without reducing the ink drying suppression effect, while adding 10% by mass or less of the total ink can also prevent a decrease in ink stability. Furthermore, adding water in this manner can reduce the amount of organic solvent used, contributing to environmental friendliness. Water may be added to the organic solvent in advance to form a hydrous organic solvent, or a specific amount may be added separately.

[0210] (Colorant) The liquid printing ink contains a colorant and can be used as a colorant-containing ink for design printing or the like to impart cosmetic properties, etc. Examples of colorants include inorganic pigments, organic pigments, and dyes used in general inks, paints, and recording agents, etc., with pigments being preferred. Examples of organic pigments include soluble azo-based, insoluble azo-based, azo-based, phthalocyanine-based, halogenated phthalocyanine-based, anthraquinone-based, anthanthrone-based, dianthraquinonyl-based, anthrapyrimidine-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, flavanthrone-based, diketopyrrolopyrrole-based, isoindoline-based, indanthrone-based, and carbon black-based pigments. Other examples include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, cromophtal yellow, cromophtal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, daylight fluorescent pigments, etc. In addition, both non-acid-treated pigments and acid-treated pigments can be used.

[0211] Examples of inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among the inorganic pigments, titanium oxide is particularly preferred. Titanium oxide exhibits a white color and is preferred in terms of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, titanium oxide is preferably treated with silica and / or alumina. Examples of inorganic pigments other than white include aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Aluminum is in powder or paste form, but is preferably used in paste form from the viewpoints of handleability and safety. Whether leafing or non-leafing is used is appropriately selected from the viewpoints of brightness and density.

[0212] The pigments are preferably contained in an amount sufficient to ensure the concentration and coloring strength of the liquid printing ink, i.e., 1 to 60% by mass of the total mass of the ink, or 10 to 90% by mass in terms of the weight ratio of solids in the ink. These pigments may be used alone or in combination of two or more.

[0213] (Other Components in Liquid Printing Ink) The liquid printing ink may further contain, as necessary, a chelating crosslinking agent, an extender pigment, a pigment dispersant, a leveling agent, an antifoaming agent, a wax, a plasticizer, an infrared absorber, an ultraviolet absorber, a fragrance, a flame retardant, etc.

[0214] (Biomass Liquid Printing Ink) In the liquid printing ink, in consideration of the creation of a recycling-oriented society that should develop sustainably (sustainability), it is preferable to use a biomass polyurethane synthesized from plant-derived raw materials. For example, a preferred biopolyurethane is one that uses, as the raw material for the polyurethane resin, a polyester polyol (hereinafter sometimes referred to as a biopolyester polyol) obtained by reacting plant-derived 1,2-propanediol, 2-methyl-1,3-propanediol, or 3-methyl-1,5-pentanediol with plant-derived polycarboxylic acid.

[0215] Furthermore, the biomass content can be increased by appropriately using biomass raw materials as raw materials for the liquid printing ink. Biomass raw materials for polyurethane resins include polycarboxylic acids such as succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, glutaric acid, and malic acid; polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, pentylene glycol, 1,10-dodecanediol, dimer diol, and isosorbide; and polyisocyanates such as 1,5-pentamethylene diisocyanate and dimer diisocyanate. Other biomass raw materials include rosin, dammar resin, cellulose acetate propionate resin, soluble cellulose, and lactic acid.

[0216] Commercially available products can also be used as biomass liquid printing inks, such as those listed by the Japan Organics Recycling Association.

[0217] (Barrier Layer) The laminate of the present invention may include a barrier layer, such as an aluminum layer, a vapor deposition layer, or a gas barrier resin layer.

[0218] For applications that do not require transparency, aluminum layers made of aluminum foil can be used alone or in combination as the barrier layer.

[0219] (Vapor-deposited layer) The laminate of the present invention may be provided with a vapor-deposited layer made of an inorganic substance and / or an inorganic oxide as a barrier layer. By using such a vapor-deposited layer, barrier properties can be imparted to the laminate of the present invention. The vapor-deposited layer can be formed by a known method using a known inorganic substance or inorganic oxide, and its composition and formation method are not particularly limited. Furthermore, the laminate of the present invention may have two or more vapor-deposited films, which may have the same composition or different compositions.

[0220] The vapor-deposited layer may be, for example, a vapor-deposited film of an inorganic substance or inorganic oxide such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc. Vapor-deposited films of inorganic oxides such as silicon oxide and aluminum oxide are transparent.

[0221] The inorganic oxides are expressed as MOx (where M represents an inorganic element), such as SiOx and AlOx. The value of x can range from 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1.5 for magnesium (Mg), 0 to 1 for calcium (Ca), 0 to 0.5 for potassium (K), 0 to 2 for tin (Sn), 0 to 0.5 for sodium (Na), 0 to 1.5 for boron (B), 0 to 1.5 for titanium (Ti), 0 to 2 for lead (Pb), 0 to 1 for zirconium (Zr), and 0 to 1.5 for yttrium (Y). In the above, when x = 0, the material is a completely inorganic element (pure substance) and is not transparent. When the value of x is at the upper limit of the range, the material is completely oxidized. Silicon (Si) or aluminum (Al) is preferably used as the vapor deposition layer, and silicon (Si) having an x ​​value in the range of 1.0 to 2.0 and aluminum (Al) having an x ​​value in the range of 0.5 to 1.5 can be used.

[0222] The vapor deposition layer can be formed on the surface of the substrate or the like by a physical vapor deposition method (PVD method) such as vacuum deposition, sputtering, or ion plating, or a chemical vapor deposition method (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, or photochemical vapor deposition.

[0223] The thickness of the vapor-deposited layer is not particularly limited as long as the vapor-deposited layer alone can exhibit a certain level of gas barrier function. The preferred thickness range varies depending on the type of metal or metal oxide to be vapor-deposited, but is preferably 0.05 to 70 nm, more preferably 0.1 to 70 nm, still more preferably 3 to 70 nm, and even more preferably 5 to 60 nm.

[0224] A metal vapor-deposited film may be used as the vapor-deposited layer. Examples of the metal vapor-deposited film include a VM-CPP film in which a metal such as aluminum is vapor-deposited on a CPP film, and a VM-OPP film in which a metal such as aluminum is vapor-deposited on an OPP film. Examples of the transparent vapor-deposited film include films in which silica or alumina is vapor-deposited on an OPP film, a PET film, a nylon film, or the like. A film in which a coating is applied to the vapor-deposited layer may be used for the purpose of protecting the inorganic vapor-deposited layer of silica or alumina.

[0225] (Gas barrier resin layer) The gas barrier resin layer can be obtained, for example, by applying a gas barrier coating agent containing a vinyl alcohol polymer and an aqueous solvent by a known coating method to form a coating film. The coating method is not particularly limited, and examples of the coating method that can be used include spraying, spin coating, dipping, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, inkjet printing, dispensing, die coating, direct gravure printing, reverse gravure printing, flexography, knife coating, and dot coating.

[0226] Specific examples of vinyl alcohol polymers include polyvinyl alcohol, ethylene vinyl alcohol, polyvinyl butyral, etc. 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.

[0227] Examples of vinyl alcohol polymers include hydrolysates of vinyl ester homopolymers or copolymers, and compounds obtained by reacting hydrolysates of vinyl ester homopolymers or copolymers with aldehydes or ketones to form acetals. Examples of vinyl alcohol polymers having a reactive functional group other than a hydroxyl group include hydrolysates of copolymers of vinyl esters and monomers having a reactive functional group, and compounds in which the hydroxyl or acetyl group of a hydrolysate of a vinyl ester homopolymer or copolymer has been modified by a known method using a compound having a reactive functional group.

[0228] Examples of vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, vinyl benzoate, and vinyl acetoacetate, and these can be used alone or in combination of two or more. Vinyl acetate is preferred.

[0229] Examples of polymerizable compounds copolymerizable with vinyl esters include ethylene, propene, 1-butene, isobutylene, 1,3-butadiene, isopropenyl acetate, 2-propenyl acetate, styrene, α-methylstyrene, vinyl chloride, acrylonitrile, maleic anhydride, methyl acrylate, methyl methacrylate, N-vinyl-N-methylformamide, vinylacetamide, N-vinylformamide, N-(hydroxymethyl)-N-vinylformamide, hydroxyethyl acrylate, methyl vinyl ketone, diacetone acrylamide, and diacetone acrylamide. Examples of suitable acrylates include acrylate, diacetone methacrylamide, acrolein, formylstyrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, diacetone acrylate, diacetone methacrylate, acetonitrile acrylate, 2-hydroxypropyl acrylate acetoacetate, butanediol acrylate acetate, vinyl sulfonic acid, acrylamide tert-butyl sulfonic acid, orthostyrene sulfonic acid, metastyrene sulfonic acid, and parastyrene sulfonic acid, and these may be used alone or in combination of two or more. Of these, ethylene, isopropenyl acetate, and 2-propenyl acetate are preferred.

[0230] When a vinyl ester and a polymerizable compound are used in combination, the amounts used can be adjusted as appropriate. From the viewpoint of gas barrier properties, however, the amount of the polymerizable compound blended is preferably kept to 60 mol % or less, and more preferably 25 mol % or less, of the total amount of the vinyl ester and the polymerizable compound.

[0231] The degree of polymerization of the vinyl ester polymer, which is the precursor of the vinyl alcohol polymer, is not particularly limited, but is, for example, 500 to 10,000, more preferably 800 to 6,000, and even more preferably 1,000 to 3,000. This makes it possible to obtain a coating agent that has an excellent balance between gas barrier properties and coatability.

[0232] The vinyl alcohol polymer preferably has a saponification degree of 90% or more, more preferably 95% or more, because it has excellent gas barrier properties. It may also be 100%. The saponification degree can be measured by FTIR using, for example, a Nicolet 5700 FTIR spectrometer controlled by OMNIC software.

[0233] When a vinyl alcohol polymer is acetalized, examples of the aldehyde used for acetalization include aliphatic aldehydes such as formaldehyde, acetaldehyde, propylaldehyde, butylaldehyde, octylaldehyde, and dodecylaldehyde; alicyclic aldehydes such as cyclohexanecarbaldehyde; aromatic aldehydes such as benzaldehyde, naphthaldehyde, anthraldehyde, phenylacetaldehyde, tolualdehyde, dimethylbenzaldehyde, cuminaldehyde, and benzylaldehyde; unsaturated aldehydes such as cyclohexene aldehyde, dimethylcyclohexene aldehyde, and acrolein; aldehydes having a heterocycle such as furfural and 5-methylfurfural; hemiacetals of glucose, glucosamine, and the like; and aldehydes having an amino group such as 4-aminobutyraldehyde. Examples of ketones include aliphatic ketones such as 2-propanone, methyl ethyl ketone, 3-pentanone, and 2-hexanone; aliphatic alicyclic ketones such as cyclopentanone and cyclohexanone; and aromatic ketones such as acetophenone and benzophenone. These can be used alone or in combination of two or more.

[0234] As the acid catalyst used in the acetalization, conventionally known organic or inorganic acids such as acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid can be used.

[0235] The vinyl alcohol polymer is preferably one obtained by acetalizing a precursor having a saponification degree of 95% or more.

[0236] Examples of methods for modifying the hydroxyl or acetyl groups of a hydrolyzed vinyl ester homopolymer or copolymer include a method of directly reacting gaseous or liquid diketene, a method of preliminarily adsorbing and occluding an organic acid such as acetic acid and then reacting gaseous or liquid diketene with this under an inert gas atmosphere, or a method of spraying a mixture of an organic acid and diketene to react with diketene (reaction generation step), followed by washing and removing unreacted diketene with an alcohol having 1 to 3 carbon atoms (washing step), and then drying under specified conditions (drying step), and a method of reacting a hydrolyzed vinyl ester homopolymer or copolymer with an acetoacetic ester to perform transesterification. This allows acetoacetyl groups to be introduced into a vinyl alcohol-based polymer.

[0237] 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 cellosolve containing propylene glycol ether, dipropylene glycol ether, and 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.

[0238] Examples of crosslinking agents include aldehydes such as formaldehyde, oxalic aldehyde, and glutaraldehyde; acetals such as diacetalized products of glutaraldehyde; aliphatic polyisocyanates such as hexamethylene diisocyanate and its derivatives (adduct, nurate, biuret, etc.), aromatic aliphatic polyisocyanates such as xylylene diisocyanate and its derivatives, aromatic polyisocyanates such as toluene diisocyanate and its derivatives, and isocyanates such as urethane prepolymers which are reaction products of these isocyanates with polyols; epoxies; organometallic compounds of titanium, silicon, aluminum, zirconium, boron, etc. with alkoxides; and methylol urea, methylol melamine, etc. carboxyl group-containing polymers such as polyacrylic acid polymers and maleic anhydride polymers; carbodiimides such as p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), and cyclohexane-1,4-bis(methylene-t-butylcarbodiimide); hydrazine compounds such as methylene dihydrazine, ethylene dihydrazine, propylene dihydrazine, butylene dihydrazine, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, and sebacic acid dihydrazide; hydrazide compounds such as adipic acid dihydrazide, carbodihydrazide, and polyhydrazide; boric acid; and titanium lactate. The isocyanates may be blocked isocyanates prepared using known blocking agents, or emulsion-type isocyanates.

[0239] The amount of the crosslinking agent to be added is adjusted as appropriate, but is, for example, 0.5 to 30 parts by mass per 100 parts by mass of the vinyl alcohol polymer.

[0240] As an adhesion improver capable of improving adhesion to a substrate, particularly an olefin resin substrate, an imine resin such as polyalkyleneimine can also be used in combination. Polyalkyleneimine is a resin having a polyalkyleneimine skeleton, and is obtained by polymerizing one or more alkyleneimines (e.g., ethyleneimine, propyleneimine) by a conventional method. The polyalkyleneimine (A2) may be a linear polyalkyleneimine consisting of a linear polyalkyleneimine chain, or a branched polyalkyleneimine having a branched polyalkyleneimine chain. Examples of the polyalkyleneimine (A2) include polyethyleneimine and polypropyleneimine. The polyalkyleneimine (A2) may have a substituent (e.g., a hydroxypropyl group, a hydroxyethyl group) introduced into at least some of the nitrogen atoms of the polyalkyleneimine chain. Those modified with an organometallic compound such as tetraisopropyl titanate, tetra-normal butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, tetramethyl titanate, polyhydroxytitanium stearate, titanium bisacetylacetonate, titanium tetraacetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium ethylacetoacetate, titanium lactate, titanium triethanolaminate, or titanium stearate may also be used, and two or more types of polyalkyleneimines can also be used in combination.

[0241] The polyalkyleneimine (A2) is believed to contribute to improving the adhesion between the vinyl alcohol polymer (A1) and the olefin film through its amino groups (NHR groups, NH groups) and ethylene groups. Because this is effective in improving adhesion, it is preferable that the polyalkyleneimine (A2) contain a branched polyalkyleneimine. The degree of branching of the polyalkyleneimine (A2) can be expressed by the proportion of primary, secondary, and tertiary amino groups contained in the polyalkyleneimine (A2). While this can be appropriately adjusted depending on the vinyl alcohol polymer (A1) used and its blending amount, it is preferable to use, as an example, a polyalkyleneimine (A2) having a proportion of primary amino groups of 20 to 40%, a proportion of secondary amino groups of 30 to 60%, and a proportion of tertiary amino groups of 20 to 35%. The proportions of primary, secondary, and tertiary amine groups contained in the polyalkyleneimine (A2) can be measured by C-NMR spectroscopy. The branched polyalkyleneimine is preferably a branched polyethyleneimine.

[0242] The number average molecular weight of the polyalkyleneimine (A2) is preferably 5,000 or more, more preferably 9,000 or more, and even more preferably 50,000 or more, because this provides excellent adhesion. The upper limit is not particularly limited, but an example is 100,000 or less. The number average molecular weight of the polyalkyleneimine (A2) is measured by GPC (gel permeation chromatography) using pullulan as a standard substance.

[0243] In the coating agent of the present invention, the blending amount of polyalkylimine (A2) is preferably 1% by mass or more and 90% by mass or less of the total amount of vinyl alcohol polymer (A1) and polyalkylimine (A2). This makes it possible to more reliably improve adhesion to olefin-based substrates while maintaining the gas barrier properties of the coating agent of the present invention. More preferably, it is 10% by mass or more and 50% by mass or less. When the coating agent of the present invention does not contain polyalkyleneimine (A2), adhesion to olefin-based substrates is insufficient. When the vinyl alcohol-based polymer (A1) is not contained (when the resin (A) consists only of polyalkyleneimine (A2)), the coating film is sticky and is not suitable for post-processing.

[0244] The amount of the gas barrier coating agent applied is adjusted appropriately depending on the desired level of gas barrier properties. For example, ２ ~5.0g / m ２ , more preferably 0.3 g / m ２ ~2.0 g / m ２ is.

[0245] Commercially available gas barrier coating agents can also be used, and examples thereof include EXEVIA (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., the SunBar (registered trademark) series manufactured by Sun Chemical Co., Ltd., the Takelac WPB (registered trademark) series manufactured by Mitsui Chemicals, Inc., and LG-OX manufactured by Tokyo Ink Co., Ltd.

[0246] The gas barrier resin layer may be composed primarily of a reaction product of a polyester polyol (Y1), which is a reaction product of a polyol component and an acid component essentially containing an ortho-orientated polycarboxylic acid or a meta-orientated polycarboxylic acid, and an isocyanate compound (B).

[0247] (Ortho-orienting Polycarboxylic Acid or Meta-orienting Polycarboxylic Acid as Acid Component) Examples of the ortho-orienting polycarboxylic acid used in the synthesis of polyester polyol (Y1) 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 the substituent 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.

[0248] Examples of meta-oriented polycarboxylic acids used in the synthesis of polyester polyol (Y1) include isophthalic acid and 1,3-naphthalenedicarboxylic acid. These compounds may have a substituent on any carbon atom of the aromatic ring. Examples of the substituent 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.

[0249] (Acid Component and Other Polycarboxylic Acids) The polycarboxylic acid used as the acid component in the synthesis of polyester polyol (Y1) may contain a polycarboxylic acid other than the above-mentioned ortho-orientated polycarboxylic acid or meta-orientated polycarboxylic acid. Examples of such 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, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 1,5-anthracenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, 1,4-anthracenedicarboxylic acid, and the like. Examples of aromatic polycarboxylic acids include helical dicarboxylic acids, 2,6-anthracene dicarboxylic acid, 2,7-anthracene dicarboxylic acid, 1,8-anthracene dicarboxylic acid, 9,10-anthracene dicarboxylic acid, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and acid anhydrides or ester-forming derivatives of these dicarboxylic acids, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids, and these can be used alone or in combination of two or more. Among these, succinic acid, 1,3-cyclopentane dicarboxylic acid, and acid anhydrides thereof are preferred.

[0250] When the polycarboxylic acid contains a polycarboxylic acid other than an ortho-oriented polycarboxylic acid or a meta-oriented polycarboxylic acid, the proportion of the ortho-oriented polycarboxylic acid or the meta-oriented polycarboxylic acid in the total amount of the polycarboxylic acid is preferably 40 to 100 mass%.

[0251] (Polyol Component) The polyol component used in the synthesis of polyester polyol (Y1) preferably contains a dihydric alcohol such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, or cyclohexanedimethanol, or a trihydric alcohol such as glycerol, trimethylolethane, or trimethylolpropane. Among these, it is more preferable to contain ethylene glycol or glycerol. It is particularly preferable to contain glycerol. The polyol component of polyol (A) preferably contains 10 to 100% by mass of glycerol.

[0252] 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 glycerin, trimethylolpropane, trimethylolethane, 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 phenols.

[0253] When the polyester polyol (Y1) has three or more hydroxyl groups (referred to as polyester polyol (Y1) for convenience), some of the hydroxyl groups may be modified with acid groups. Such a polyester polyol is also referred to as polyester polyol (A1') below. The polyester polyol (A1') is obtained by reacting the polyester polyol (Y1) 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 (Y1). 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.

[0254] The hydroxyl value of the polyester polyol (Y1) is preferably 20 mgKOH / g or more and 250 mgKOH / g or less. If the hydroxyl value is less than 20 mgKOH / g, the molecular weight is too large, so the viscosity of the polyol composition (X) increases, and the coating temperature must be increased when the composition is used as a solventless adhesive, for example. If the hydroxyl value exceeds 250 mgKOH / g, the crosslink density of the cured coating film may become too high, resulting in a decrease in adhesive strength.

[0255] When the polyester polyol (Y1) has an acid group, the acid value is preferably 200 mgKOH / g or less. If the acid value exceeds 200 mgKOH / g, the reaction between the polyol and the polyisocyanate may become too rapid, resulting in a decrease in coatability. The lower limit of the acid value is not particularly limited, but is, for example, 20 mgKOH / g or more. When the acid value is 20 mgKOH / g or more, good gas barrier properties and initial cohesion strength can be obtained due to intermolecular interactions. 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.

[0256] The number average molecular weight of the polyester polyol (Y1) is particularly preferably 300 to 5000, since a crosslinking density sufficient to achieve an excellent balance between adhesiveness and gas barrier properties 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.

[0257] The glass transition temperature of the polyester polyol (Y1) 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 a substrate and gas barrier properties.

[0258] The polyester polyol (Y1) may be a polyester polyurethane polyol having a number average molecular weight of 1,000 to 15,000 obtained by urethane elongation through a reaction with a diisocyanate compound. 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 gas barrier properties and initial cohesion.

[0259] The polyester polyol (Y1) may be used alone or in combination of two or more polyols.

[0260] (Isocyanate Compound (B)) The isocyanate compound (B) can be any known compound without any particular limitation, and examples thereof include adducts obtained by reacting 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 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. Polyester polyisocyanates obtained by reacting polyester polyols (Y1) to (A3) with a diisocyanate compound in an isocyanate excess ratio relative to hydroxyl groups may also be used. These may be used alone or in combination of two or more.

[0261] In addition, a blocked isocyanate 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 cyclohexanoneoxime, 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.

[0262] The isocyanate compound (B) preferably has an aromatic ring or an aliphatic ring, which is expected to improve the gas barrier properties and blocking resistance of the coating film. Among the isocyanate compounds, examples of the isocyanate compound having an aromatic ring or an aliphatic ring include 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 such as polyamides.

[0263] The isocyanate compound (B) may be used alone or in combination of two or more types of isocyanate compounds.

[0264] When a polyester polyol having residual carboxylic acid groups, such as polyester polyol (A1′), is used as polyol (A), an epoxy compound may be used in combination with the polyisocyanate 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 ethers of glycerol alkylene oxide adducts, and the like.

[0265] 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.

[0266] The gas barrier resin layer may preferably contain a compound (C) having an active hydrogen group. Examples of the active hydrogen group in the compound (C) having an active hydrogen include a hydroxyl group, an amino group, an imino group, a carboxylic acid, a urea group, and an SH group. Of these, a hydroxyl group, an amino group, and an SH group are preferred.

[0267] Furthermore, when the solubility parameter of the compound (C) is 29.5 or less, the compatibility between the polyol (A) and the isocyanate compound (B) is improved, and a coating film containing the compound (C) uniformly distributed therein can be formed, which is expected to have improved gas barrier properties. In the present invention, the solubility parameter is the δT value listed in the Hansen Solubility Parameter Calculation Software (HSPiP) or the δT value calculated using the SMILES notation.

[0268] The number average molecular weight of the compound (C) is preferably in the range of 100 or more and 250 or less.

[0269] Examples of the compound (C) having a hydroxyl group as the active hydrogen group include alkanols such as octanol and decanol, aliphatic diols such as 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, 3,3-dimethylolheptane, octanediol, and decanediol, alicyclic alcohols such as 1,3- or 1,4-cyclohexanedimethanol and 1,3- or 1,4-cyclohexanediol, aromatic alcohols such as salicylic alcohol and vanillyl alcohol, hydrogenated bisphenol A, and 1,4-dihydroxy-2-butene. Examples of the alcohol include dihydric alcohols such as 2,6-dimethyl-1-octene-3,8-diol, bisphenol A, diethylene glycol, triethylene glycol, and dipropylene glycol; trihydric alcohols such as glycerin, trimethylolpropane, and triisopropanolamine; tetrahydric alcohols such as tetramethylolmethane (pentaerythritol) and diglycerin; pentahydric alcohols such as xylitol; hexahydric alcohols such as sorbitol, mannitol, allitol, iditol, dulcitol, altritol, inositol, and dipentaerythritol; and heptahydric alcohols such as perseitol.

[0270] Examples of the compound (C) having an amino group as the active hydrogen group include aliphatic amines such as octylamine, decaneamine, 1,8-diaminooctane, and 1,10-diaminodecane; alicyclic amines such as isophoronediamine, norbornenediamine, bis(aminomethyl)cyclohexane, cyclohexanediamine, diaminodicyclohexylmethane, and methylenebis(methylcyclohexaneamine); and aromatic amines such as 1-xylylenediamine, N-benzylethylenediamine, phenylenediamine, diaminodiphenylmethane, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, toluenediamine, and diethyltoluenediamine.

[0271] Examples of the compound (C) having an SH group as the active hydrogen group include hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, undecyl mercaptan, dodecyl mercaptan, tridecyl mercaptan, tetradecyl mercaptan, pentadecyl mercaptan, mercaptophenol, mercaptopropionic acid, mercaptobutyric acid, 1,4-butanedithiol, 2-mercaptobenzothiazole, 3 ... 3-mercapto-1,2-propanediol, mercaptomethylbutanol, 3-mercapto-2-methylpentanol, 3-mercapto-3-methylbutanol, 4-ethoxy-2-methyl-2-butanethiol, hexanethiol, dimethylthiophenol, 1,4-bis(3-mercaptobutyryloxy)butane, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate), and the like.

[0272] The compound (C) may be used alone or in combination of two or more kinds. Among them, the compound (C) having a hydroxyl group as the active hydrogen group is preferred, and isosorbide, tris(2-hydroxyethyl) isocyanurate, trimethylolpropane, dipentaerythritol, and 1,4-cyclohexanedimethanol are preferred.

[0273] The blending amount of the compound (C) is preferably 0.5% by mass or more and 20% by mass or less based on the solid content of the gas barrier resin layer. Within this range, winding blocking during coating is prevented, and good substrate adhesion and improved gas barrier properties of the coating film are expected. A blending amount of 1% by mass or more and 15% by mass or less is more preferred, and 2% by mass or more and 8% by mass or less is most preferred.

[0274] (Other Components) The gas barrier resin layer may contain a plate-like inorganic compound (E). When the plate-like inorganic compound (E) is used in combination, the barrier properties are improved due to the plate-like shape. Examples of the plate-like inorganic compound (E) used in the present invention include hydrous silicates (phyllosilicate minerals, etc.), kaolin, kaolinite-serpentine clay minerals (halloysite, kaolinite, endelite, dickite, nacrite, etc., antigorite, chrysotile, etc.), pyrophyllite-talc (pyrophyllite, talc, kerolite, etc.), smectite clay minerals (montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, stevensite, etc.), vermiculite clay minerals (vermiculite, etc.), mica or mica clay minerals (muscovite, mica such as phlogopite, margarite, tetrasilylic mica, taeniolite, etc.), chlorite (cookkeite, sudoite, clinochlore, chamosite, nimite, etc.), hydrotalcite, plate-like barium sulfate, boehmite, aluminum polyphosphate, and the like. These minerals may be natural clay minerals or synthetic clay minerals. The plate-like inorganic compounds (E) may be used alone or in combination of two or more. The aspect ratio, content in the coating agent, particle size, and particle size distribution of these plate-like inorganic compounds (E) are not particularly limited as long as they can impart barrier improvement function and anti-blocking properties.

[0275] The amount of the plate-like inorganic compound (E) is preferably 5% by mass or more and 80% by mass or less, based on the solid content of the gas barrier resin layer. Within this range, improvements in the adhesion of the coating agent to the substrate, the coating appearance, and the gas barrier properties of the coating film are expected. A blending amount of 10% to 60% is more preferred, and a blending amount of 20% to 50% is most preferred.

[0276] The gas barrier resin layer can also contain known acid anhydrides as additives to improve acid resistance. Examples of acid anhydrides 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. It is preferable to use non-petroleum-derived components as raw materials for these acid anhydrides, as this increases the proportion of non-petroleum-derived components. An example of such a compound is succinic anhydride.

[0277] Furthermore, if necessary, a material having a gas trapping function may be added. Examples of materials having an oxygen trapping 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. Examples of materials having a water vapor trapping function include silica gel, zeolite, activated carbon, and calcium carbonate. In addition to these, a trapping component for the target gas to be blocked can be added.

[0278] In addition, various additives may be blended to the extent that the gas barrier auxiliary function is not impaired. Examples of additives include inorganic fillers such as silica, alumina, aluminum flakes, and glass flakes, and when inorganic materials are used, dispersants, stabilizers (antioxidants, heat stabilizers, ultraviolet absorbers, and the like), adhesion improvers, crosslinking agents, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, leveling agents, and slip improvers.

[0279] (Coating Agent) The gas barrier resin layer can be obtained by applying a coating agent, which is a mixture of the polyol (A) and the isocyanate compound (B), to a substrate in the form of a layer, followed by a reaction. Generally, polyol compounds and isocyanate compounds are highly reactive with each other, so coating agents made from these compounds are typically used as "two-component curing agents," in which the polyol (A) and the isocyanate compound (B) are mixed immediately before coating. The gas barrier coating agent of the present invention is also typically used as a two-component curing coating agent. The term "two-component" as used herein refers to two components: a polyol composition (Y) containing the polyol (A) as a main component, and an isocyanate composition (B) containing the isocyanate compound (B) as a main component.

[0280] It is preferable to determine whether the compounds and additives that can be used in combination are blended into the polyol (A) or the isocyanate compound (B) in consideration of reactivity. For example, the compound (C) having an active hydrogen group described above is usually blended into the polyol composition (Y) and used because it has an active hydrogen group. The plate-like inorganic compound (E) does not particularly contribute to reactivity, so it may be blended into either the polyol composition (Y) or the isocyanate composition (B). When blending, known dispersion and mixing methods can be used.

[0281] In the coating agent, the reactive component of the isocyanate compound contained in the isocyanate composition (B) and the hydroxyl group of the polyol contained in the polyol composition (Y) are preferably blended in an equivalent ratio of 0.5 / 1 to 5 / 1, and from the viewpoint of barrier function and blocking resistance, more preferably 0.8 / 1 to 2.5 / 1. If the polyisocyanate component is in excess of this range, the excess polyisocyanate component will remain, tending to result in poor blocking resistance, while if the polyester (B) is too much, the cured coating film will become too hard and good adhesive strength may not be obtained.

[0282] (Solvent Used in Coating Agent) A solvent may be used in the coating agent as appropriate. From the viewpoint of quick drying and also compensating for the water vapor barrier function, the solvent used is preferably non-aqueous, and preferably contains an organic solvent as the main component. Specifically, it is preferable that the solvent has high solubility in the polyester, which is the main component, and has no residual solvent and quick drying properties. From this viewpoint, organic solvents with a boiling point of 100°C or less are preferred. Examples of organic solvents that are preferably used include ethyl acetate, propyl acetate, and butyl acetate as ester solvents, acetone and 2-butanone as ketone solvents, tetrahydrofuran as ether solvents, hexane and cyclohexane as aliphatic solvents, and toluene as aromatic solvents. When an alcohol solvent or water is mixed, it is preferable to keep the amount to a minimum because an isocyanate compound is used in combination as a curing agent.

[0283] The thickness of the gas barrier resin layer is preferably selected from the range of, for example, 0.05 μm or more and 30 μm or less.

[0284] (Packaging Material) The laminate of the present invention can be used as a packaging material for food, medicine, etc., by using the sealant film of the present invention as a sealant. When used as a packaging material, the layer structure can be changed depending on the contents, the usage environment, and the usage form. In addition, the package of the present invention may be appropriately provided with an easy-open treatment or a resealable means. Packaging materials made of a laminate including the sealant film of the present invention have good sealing properties and good heat resistance, transparency, and impact resistance, and are therefore particularly suitable for use as packaging materials for retort foods.

[0285] The packaging material of the present invention can be obtained, for example, by overlapping the sealant film of the present invention so that the surfaces face each other, and then heat-sealing the peripheral edges to form a bag. Examples of bag-making methods include folding or overlapping the laminate of the present invention so that the inner layer surfaces (sealant layer surfaces) face each other, and heat-sealing the peripheral edges using, for example, a side seal, two-sided seal, three-sided seal, four-sided seal, envelope seal, flared seal, flat-bottom seal, square-bottom seal, gusset seal, or other heat seal methods. The packaging material of the present invention can take various forms depending on the contents, usage environment, and usage pattern. Bags can also be made into various shapes, such as self-standing packaging materials (standing pouches) and tubes. Heat-sealing methods can be known, such as bar seal, rotary roll seal, belt seal, impulse seal, high-frequency seal, and ultrasonic seal.

[0286] Furthermore, after the packaging material of the present invention is made into a bag, an opening start portion such as a V notch or an I notch may be provided, if necessary.

[0287] The packaging material of the present invention is filled with contents through its opening, and then the opening is heat-sealed to produce a product using the packaging material of the present invention. Examples of contents to be filled include foods such as rice crackers, bean snacks, nuts, biscuits, cookies, wafer snacks, marshmallows, pies, semi-dried cakes, candies, and snacks; bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, porridge, rice porridge, packaged rice cakes, and cereal foods; pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, processed wild vegetables, jams, peanut cream, salads, frozen vegetables, and processed potato products; livestock products such as ham, bacon, sausages, processed chicken, and corned beef; and fish meat and vegetables. Examples of such processed seafood products include sausages, fish paste products, kamaboko (fish paste), nori (seaweed), tsukudani (simmered foods), bonito flakes, salted fish, smoked salmon, and spicy cod roe; fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries; vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes; cooked foods such as frozen and chilled prepared dishes, including hamburger steaks, meatballs, fried seafood, gyoza, and croquettes; dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula; liquid seasonings, retort curry, and pet food.

[0288] In addition, the present invention can also be used as a packaging material for various non-food products, such as cigarettes, disposable body warmers, medicines such as infusion packs, liquid laundry detergent, liquid kitchen detergent, liquid bath detergent, liquid bath soap, liquid shampoo, liquid conditioner, cosmetics such as lotion and emulsion, vacuum insulation materials, batteries, etc.

[0289] The laminate of the present invention and a packaging material for retort food using the laminate can be suitably used for packaging foods that require treatment under high-temperature hot water conditions, such as boiling or retort sterilization, and can be suitably applied to packaging various retort foods, such as curry, stew, soup, and cooking sauces.

[0290] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" refers to "parts by mass" and "%" refers to "% by mass".

[0291] Example 1 The following resins were used as resin components for forming the substrate layer, intermediate layer, and seal layer to prepare resin mixtures for forming each layer. Substrate layer: Propylene-ethylene block copolymer (1) (haze of 5% when formed into a single film, density of 0.90 g / cm ３ 90 parts of ethylene-butene copolymer (density 0.86 g / cm 3, MFR 3.2 g / 10 min (230°C, 21.18 N), melting point 161°C) (hereinafter referred to as BCOPP) ３ 10 parts of EB (polyethylene glycol ether, MFR 6.7 g / 10 min (230°C, 21.18 N), melting point 66°C). Intermediate layer: the same resin mixture as the substrate layer. Sealing layer: the same resin mixture as the substrate layer.

[0292] The resin mixtures forming each layer were fed to three extruders, melted at 260°C, and melt-extruded into a T-die film production apparatus having a feed block (feed block and T-die temperature: 260°C) so that the average thickness ratio of the layers of the sealant film formed by the base layer / intermediate layer / sealing layer was 20%:60%:20%, and cooled with a water-cooled metal cooling roll at 40°C to obtain a sealant film with a total thickness of 60 μm. In addition, corona treatment was performed online on one side.

[0293] Example 2 A sealant film of Example 2 was obtained in the same manner as in Example 1, except that 100 parts of BCOPP was used as the resin for the sealing layer.

[0294] Examples 3 to 8 Sealant films of Examples 3 to 8 were obtained in the same manner as in Example 1, except that the film configurations were as shown in Table 1.

[0295] Comparative Example 1 A sealant film of Comparative Example 1 was obtained in the same manner as in Example 1, except that 100 parts of BCOPP was used as the resin component for all layers.

[0296] (Comparative Example 2) The resin composition of the base layer and the intermediate layer was 70 parts of BCOPP, 10 parts of EB, and linear low-density polyethylene resin (density 0.92 g / cm ３A sealant film of Comparative Example 2 was obtained in the same manner as in Example 1, except that the amount of LLDPE was changed to 20 parts of LLDPE (20 parts by weight, MFR 2.0 g / 10 min (230°C, 21.18 N), melting point 120°C).

[0297] Comparative Example 3 A sealant film of Comparative Example 3 was obtained in the same manner as in Example 1, except that the resin compositions of the base layer and intermediate layer were changed to 80 parts BCOPP, 10 parts EB, and 10 parts LLDPE.

[0298] The compositions of Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 1. The abbreviations for the materials in Table 1 are as follows: BCOPP1: propylene-ethylene block copolymer (1) (haze of 5% when formed into a single film, density of 0.90 g / cm ３ , MFR 3.2 g / 10 min (230 ° C, 21.18 N), melting point 164 ° C) BCOPP2: propylene-ethylene block copolymer (1) (haze 5.3% when formed into a single film, density 0.90 g / cm ３ , MFR 2.5 g / 10 min (230 ° C, 21.18 N), melting point 165 ° C) EB: ethylene-butene copolymer (density 0.86 g / cm ３ , MFR 6.7 g / 10 min (230 ° C, 21.18 N), melting point 66 ° C) PB: propylene-butene copolymer (density 0.87 g / cm ３ , MFR 7.0 g / 10 min (230 ° C, 21.18 N), melting point 75 ° C) LLDPE: Linear low-density polyethylene resin (density 0.92 g / cm ３ , MFR 2.0 g / 10 min (230 ° C, 21.18 N), melting point 120 ° C)

[0299] The sealant films obtained in the above Examples and Comparative Examples were evaluated as follows, and the results are shown in the table below.

[0300] [Evaluation] (Haze) The haze (unit: %) of the sealant films obtained in the above Examples and Comparative Examples was measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS K 7105. In the present invention, the haze is preferably 10% or less, and more preferably 5% or less.

[0301] (Impact Strength) The sealant films obtained in the Examples and Comparative Examples were left to stand for 4 hours in a thermostatic chamber adjusted to below 0°C. Thereafter, a BU-302 film impact tester manufactured by Tester Sangyo Co., Ltd. was used to attach a 1.5-inch head to the tip of a pendulum and measure the impact strength by the film impact method. In the present invention, impact strength of 0.9 J or more is preferred, and impact strength of 1.0 J or more is more preferred.

[0302] (Preparation of Laminate Film) A polybutylene terephthalate (PBT) film (thickness 25 μm) was attached by dry lamination to the surface of the base layer of the sealant film obtained in the above Examples and Comparative Examples so as to have a configuration of PBT film / adhesive layer / sealant film, and the resulting film was aged at 40° C. for 48 hours to obtain a laminate film for evaluation. In this case, a two-component curing adhesive (polyester adhesive "DIC Dry LX500" and curing agent "DIC Dry KR-90S") manufactured by DIC Corporation was used as the dry lamination adhesive to form the adhesive layer.

[0303] (Seal strength of laminate film) The seal layer surfaces of the obtained laminate film were overlapped and heat-sealed for 1.0 second at a temperature of 190 ° C. and a pressure of 0.2 MPa to obtain a test piece, which was then subjected to heat treatment at 135 ° C. for 30 minutes using a high-temperature, high-pressure cooking sterilization device. The sample after heat sterilization treatment was cut into a width of 15 mm, and the seal strength was measured using a tensile tester (manufactured by A & D Co., Ltd.) in a thermostatic chamber at 23 ° C. and 50% RH.

[0304] (Bag Drop Test) A film measuring 22 cm long x 18 cm wide was cut from the obtained laminate film and folded in half so that the sealing layer surfaces of the film overlapped. Two vertical sides and one horizontal side were heat-sealed 1 cm from the edge at 190 ° C, 0.2 MPa, and 1 second to create a three-sided bag. 230 ml of water was poured into the obtained three-sided bag, and the open end was sealed under the above heat-sealing conditions. A high-temperature, high-pressure cooking sterilization device was used to heat-treat the bag at 135 ° C for 30 minutes. The three-sided bag sample after heat sterilization was dropped from a height of 150 mm to determine the number of drops required before the bag broke or water leaked.

[0305] (Retort resistance) A seal strength of 35 N / 15 mm or more and a drop count of 10 or more was evaluated as ⊚, and a drop count of less than 10 was evaluated as x. A drop count of 10 or more and a seal strength of less than 35 N / 15 mm was evaluated as Δ.

[0306]

[0307] As is clear from Table 1 above, the sealant films of the present invention in Examples 1 to 8 had good impact resistance while suppressing haze, maintained seal strength after retort treatment, and were able to withstand the drop test. On the other hand, the sealant film of Comparative Example 1 did not contain an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer in the base layer, and showed particularly poor results in the drop test. The sealant films of Comparative Examples 2 and 3 had a polypropylene resin ratio of less than 85% by mass, and therefore did not achieve good retort resistance.

[0308] <Preparation of Packaging Film 1> A film (25 μm thick) in which 20 nm of aluminum oxide (hereinafter abbreviated as AlOx) was vapor-deposited on a biaxially oriented polypropylene film (hereinafter abbreviated as OPP film) was attached to the surface of the base layer of the sealant film obtained in Example 1 by dry lamination, and aged at 40 ° C. for 48 hours to obtain a laminate film. A pattern was printed on top of this using printing ink (DIC's "Finart F407B Medium Yellow / R794 White"), and then dried with a dryer to form a printed layer. The first substrate (OPP film) was attached by dry lamination, and aged at 40 ° C. for 48 hours to confirm that a packaging film could be obtained. In this case, a two-component curing adhesive (polyester adhesive "DIC Dry LX530" and curing agent "DIC Dry KO-55") manufactured by DIC Corporation was used as the dry lamination adhesive to form the adhesive layer. The resulting packaging film had a structure of OPP / printing layer / adhesive layer / AlOx / OPP / adhesive layer / sealant film.

[0309] <Preparation of Packaging Film 2> A biaxially oriented polyethylene terephthalate (PET) film (thickness 12 μm) and aluminum foil (thickness 7 μm) were attached by dry lamination to the surface of the base layer of the sealant film obtained in Example 1, in a configuration of PET film / adhesive layer / aluminum foil / adhesive layer / sealant film, and the resulting mixture was aged at 40° C. for 72 hours, confirming that a packaging film could be obtained. In this case, a two-component curing adhesive (polyester adhesive "DICdry LX530" and curing agent "DICdry KO-55") manufactured by DIC Corporation was used as the dry lamination adhesive to form the adhesive layer.

[0310] <Packaging Film Preparation 3> A biaxially oriented polyethylene terephthalate (PET) film (12 μm thick), aluminum foil (7 μm thick), and nylon film (15 μm thick) were dry-laminated onto the surface of the base layer of the sealant film obtained in Example 5, forming a PET film / adhesive layer / aluminum foil / adhesive layer / nylon / adhesive layer / sealant film. The resulting laminate was then aged at 40°C for 72 hours, confirming that a packaging film could be obtained. In this case, a two-component curing adhesive (polyester adhesive "DIC Dry LX530" and curing agent "DIC Dry KO-55") manufactured by DIC Corporation was used as the dry lamination adhesive for the adhesive layer. The resulting laminate film had a seal strength of 54 N and a drop test result of 24, resulting in a good retort resistance rating (◎).

Claims

1. A sealant film comprising at least a substrate layer and a sealing layer, The substrate layer comprises a propylene-based block copolymer and an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer. The sealing layer comprises a propylene-based block copolymer and an ethylene-α-olefin copolymer and / or a propylene-α-olefin copolymer. The ratio of polypropylene resin to the total amount of resin components constituting the sealant film is 85% by mass or more. The MFR of the seal layer is 2.8 to 3.6 g / 10 min (230°C, 21.18 N). Sealant film.

2. The sealant film according to claim 1, wherein the content of the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer in the sealant film is 2 to 20% by mass.

3. The sealant film according to claim 1, wherein the ethylene-α-olefin copolymer and / or propylene-α-olefin copolymer is an ethylene-butene copolymer and / or propylene-butene copolymer.

4. A laminate using the sealant film described in any one of claims 1 to 3 as a sealant.

5. A packaging material containing the laminate described in claim 4.

6. The packaging material according to claim 5, for use in retort packaging of food products.