Coating agent for vapor deposition film, gas barrier film, and packaging material

Abstract

The present invention provides a coating agent for a vapor deposition film, which contains a urethane resin (A) and an aqueous medium (B), and is characterized in that the urethane resin (A) is a reaction product of a composition that contains a polyester (A3) that is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), the urethane resin (A) has an ester skeleton derived from the polyester (A3), and contains 10-100 mass% of at least one of an aromatic dicarboxylic acid and an acid anhydride thereof with respect to 100 mass% of the total amount of the polycarboxylic acid (A1), and the polyol component (A2) contains an alkylene glycol having 2-6 carbon atoms. The coating agent for a vapor deposition thin film exhibits excellent gas barrier properties and adhesiveness even in a normal state and after a retort treatment.

Description

Technical Field

[0001] The present invention relates to a coating agent for a vapor-deposited film, a gas barrier film and a packaging material. Background Art

[0002] In order to protect the contents from deterioration due to oxygen, water vapor, etc., packaging materials for food, beverages, etc. are often required to have gas barrier properties.

[0003] As a method of providing a packaging material with a gas barrier property, a method of applying a gas barrier coating to a stretched film, a method of providing a gas barrier resin to a layer in a multilayer film by coextrusion, and the like are widely used.

[0004] Among them, the vapor deposition method of providing a vapor-deposited layer on a thin film is an excellent method that can easily provide a barrier function regardless of the type of gas. In particular, a transparent vapor-deposited film is excellent in transparency and excellent in gas barrier properties under high humidity.

[0005] On the other hand, even when a transparent vapor-deposited film is used, there may be a problem that the gas barrier properties are reduced after a retort (heating / pressurizing) treatment.

[0006] Therefore, by overcoating the resin layer on the transparent deposited layer of the transparent deposited film, it is possible to obtain a transparent deposited film having excellent gas barrier properties and adhesiveness even after a retort treatment.

[0007] As a general-purpose resin layer used for the outer coating, polyvinyl alcohol (PVA) as a gas barrier resin can be used. However, PVA has high hydrophilicity, so after the steaming treatment, it sometimes delaminates from the transparent vapor-deposited layer, and an outer coating layer with high adhesion and gas barrier properties is required even after the steaming treatment.

[0008] As a technique for coating on a transparent vapor-deposited layer, for example, a transparent gas barrier laminate is disclosed, which has a gas barrier coating layer formed by coating a gas barrier coating liquid on an inorganic oxide layer (transparent vapor-deposited layer), wherein the gas barrier coating liquid contains a water-soluble polymer and contains at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, or tin chloride, and an aqueous solution or a water / alcohol mixed solution as a main component (for example, Patent Documents 1 and 2). However, the water-soluble polymer has poor coating drying properties and also includes a sol-gel process that is difficult to control the reaction. Therefore, there are problems such as difficulty in reaction management or reuse of the coating liquid and complicated coating methods.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Publication No. 2012-101505

[0012] Patent Document 2: Japanese Patent Application Publication No. 2012-250470 Summary of the invention

[0013] Problem that the invention aims to solve

[0014] Therefore, the problem to be solved by the present invention is to provide a coating agent for a vapor-deposited film, a gas barrier film and a packaging material that can obtain a gas barrier film having excellent gas barrier properties and adhesiveness even in a normal state and after a retort treatment, and a packaging material using the above-mentioned gas barrier film.

[0015] Solutions for solving problems

[0016] The present inventors have conducted intensive studies and have found that by using a coating agent for a vapor-deposited film containing a urethane resin and an aqueous medium, wherein the urethane resin is a reaction product of a composition containing a specific polyester, an active hydrogen group-containing compound having a hydrophilic group, and a diisocyanate, a gas barrier film having excellent gas barrier properties and adhesiveness even in normal conditions and after a retort treatment, and a packaging material using the aforementioned gas barrier film can be obtained, thereby completing the present invention.

[0017] That is, the present invention relates to a coating agent for a vapor-deposited film, which contains a carbamate resin (A) and an aqueous medium (B), wherein the carbamate resin (A) is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2), wherein the carbamate resin (A) has an ester skeleton derived from the polyester (A3), contains 10 to 100% by mass of at least one of an aromatic dicarboxylic acid or an anhydride thereof, relative to 100% by mass of the total amount of the polycarboxylic acid (A1), and wherein the polyol component (A2) contains an alkylene glycol having 2 to 6 carbon atoms.

[0018] In the coating agent for a vapor-deposited film of the present invention, the composition preferably further contains a chain extender (A6).

[0019] The coating agent for a vapor-deposited film of the present invention preferably contains a curing agent (C).

[0020] The coating agent for a vapor-deposited film of the present invention preferably contains 50 to 100% by mass of toluene diisocyanate based on 100% by mass of the total amount of the diisocyanate (A5).

[0021] In the coating agent for a vapor-deposited thin film of the present invention, the aqueous medium (B) is preferably water and / or isopropyl alcohol.

[0022] In the coating agent for a vapor-deposited film of the present invention, the curing agent (C) is preferably at least one selected from the group consisting of a melamine crosslinking agent, a carbodiimide crosslinking agent, and a water-dispersible polyisocyanate crosslinking agent.

[0023] The present invention relates to a gas barrier film obtained by applying the above-mentioned coating agent for a vapor-deposited film to a vapor-deposited film.

[0024] The present invention relates to a packaging material using the above-mentioned gas barrier film.

[0025] Effects of the Invention

[0026] The coating agent for the vapor-deposited film of the present invention uses an aqueous medium, so there is no problem of residual solvent. By using a specific urethane resin, when it is applied to the vapor-deposited film, the gas barrier properties of oxygen and water vapor in normal state and after boiling treatment are improved. The coating film obtained by using the coating agent for the vapor-deposited film is also excellent in adhesion (lamination strength) to the vapor-deposited film in normal state and after boiling treatment. In particular, it can provide a barrier film useful for food packaging purposes, which is useful. DETAILED DESCRIPTION

[0027] The present invention relates to a coating agent for a vapor-deposited film, comprising a carbamate resin (A) and an aqueous medium (B), wherein the carbamate resin (A) is a reaction product of a composition comprising a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2), wherein the carbamate resin (A) has an ester skeleton derived from the polyester (A3), contains 10 to 100% by mass of at least one of an aromatic dicarboxylic acid or an anhydride thereof, relative to 100% by mass of the total amount of the polycarboxylic acid (A1), and wherein the polyol component (A2) contains an alkylene glycol having 2 to 6 carbon atoms.

[0028] The above-mentioned coating agent for vapor-deposited films does not have the problem of residual solvent by using an aqueous medium. When applied to a vapor-deposited film, the oxygen barrier property and water vapor barrier property are improved in normal state and after boiling treatment. The coating film obtained using the coating agent for vapor-deposited films also has excellent adhesion (lamination strength) to the vapor-deposited film in normal state and after boiling treatment, and is useful.

[0029] (Urethane resin (A))

[0030] The coating agent for a vapor-deposited film of the present invention is characterized in that it contains a carbamate resin (A), wherein the carbamate resin (A) is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a condensation product of a polycarboxylic acid component (A1) and a polyol component (A2), wherein the carbamate resin (A) has an ester skeleton derived from the polyester (A3), contains 10 to 100% by mass of at least one of an aromatic dicarboxylic acid or anhydride thereof relative to 100% by mass of the total amount of the polycarboxylic acid (A1), and wherein the polyol component (A2) contains an alkylene glycol having 2 to 6 carbon atoms.

[0031] The polyester (A3) is obtained by a polycondensation reaction of a polycarboxylic acid component (A1) and a polyol component (A2), has a hydroxyl group or a carboxyl group at its terminal, and can react with the diisocyanate (A5).

[0032] The urethane resin (A) has an ester skeleton derived from the polyester (A3), and is useful in improving the adhesion between the obtained coating film and the vapor deposition surface and the gas barrier properties.

[0033] Furthermore, the urethane resin (A) is a urethane resin obtained by a polyaddition reaction of the polyester (A3) (polyester polyol) and the diisocyanate (A5), and further reacting with the active hydrogen group-containing compound (A4) having a hydrophilic group. Therefore, a urethane resin having water dispersion stability is formed by the hydrophilic group, and the dispersion of the urethane resin (particles) in an aqueous medium becomes easy.

[0034] (Polycarboxylic acid component (A1))

[0035] The urethane resin (A) is characterized in that it is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2). By using the polycarboxylic acid component (A1), a coating film obtained by using the polyester (A3) has good adhesion to a vapor deposition surface and gas barrier properties, which is useful.

[0036] Examples of the polycarboxylic acid component (A1) include succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. Examples of the polycarboxylic acid containing an unsaturated bond include maleic anhydride, maleic acid, fumaric anhydride, and fumaric acid. Examples of the alicyclic polycarboxylic acid include 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Examples of the aromatic polycarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and diphenylcarboxylic acid. Acid) and its anhydride, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid and the anhydride or ester-forming derivatives of these dicarboxylic acids; p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid and the ester-forming derivatives of these dihydroxycarboxylic acids and other polybasic acids, among which, from the viewpoint of improving gas barrier properties, aromatic polybasic carboxylic acids or their anhydrides are more preferred, and aromatic dicarboxylic acids or their anhydrides are further preferred. These can be used alone or in combination of two or more.

[0037] The invention is characterized in that, relative to 100 mass % of the total amount of the polycarboxylic acid (A1), 10 to 100 mass % of at least one of the aromatic dicarboxylic acid or its anhydride is contained, preferably 40 to 100 mass %, more preferably 60 to 100 mass %. If it is within the above range, the obtained coating film has excellent adhesion to the vapor deposition surface and gas barrier properties, which is useful.

[0038] (Polyol component (A2))

[0039] The urethane resin (A) is characterized in that it is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2), and the polyol component (A2) contains an alkylene glycol having 2 to 6 carbon atoms. By using the polyol component (A2), a coating film obtained using the obtained polyester (A3) has good adhesion to a vapor deposition surface and gas barrier properties, which is useful.

[0040] Examples of the polyol component (A2) include ethylene glycol, propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 1,6-hexanediol (hexamethylene glycol), neopentyl glycol, 3-methyl-1,5-pentanediol, 1,3-cyclohexanediol, or 1,4-cyclohexanediol, ether glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol, and olefin glycols such as 1,4-dihydroxy-2-butene. The fewer the number of carbon atoms between oxygen atoms in the polyol component, the less flexible the molecular chain. From the viewpoint of preventing oxygen from penetrating, an alkylene glycol having 2 to 6 carbon atoms, preferably an alkylene glycol having 2 to 4 carbon atoms, may be used alone or in combination of two or more.

[0041] In the coating agent for deposited film of the present invention, the alkylene glycol having 2 to 6 carbon atoms is preferably contained in an amount of 10 to 100% by mass, more preferably 20 to 100% by mass, and even more preferably 30 to 100% by mass, relative to 100% by mass of the total amount of the polyol component (A2). Within the above range, the obtained polyester has moderate hydrophobicity, and is useful in preventing the reduction of the gas barrier properties and adhesiveness (close adhesion) of the coating film caused by moisture after the retorting treatment.

[0042] From the viewpoint of obtaining a hydroxy-terminated polyester (A3) and excellent gas barrier properties and adhesion (close adhesion) of the coated coating film to the vapor deposition surface, the blending ratio (molar ratio) of the polycarboxylic acid component (A1) and the polyol component (A2) is preferably: polycarboxylic acid component (A1): polyol component (A2) = 1:1.01 to 4.0, and more preferably: polycarboxylic acid component (A1): polyol component (A2) = 1:1.1 to 3.0.

[0043] (Polymerization Catalyst)

[0044] The polymerization catalyst used in the reaction to obtain the polycondensate of the polycarboxylic acid component (A1) and the polyol component (A2), i.e., the polyester (A3), is not particularly limited, and at least one of an antimony compound, a germanium compound, a titanium compound, and an aluminum compound can be used, among which the titanium compound can be preferably used, and titanium tetraisopropoxide, titanium tetrabutoxide, etc. are more preferably used. These can be used alone or in combination of two or more.

[0045] The amount of the polymerization catalyst to be added is preferably 1 to 1000 ppm of the polymerization initiator, more preferably 10 to 100 ppm, relative to the total amount of the reaction raw materials used. Within the above range, the esterification reaction proceeds well and the urethanization reaction when reacting with the diisocyanate (A5) is not hindered, so it is preferred.

[0046] (Polyester (A3))

[0047] The coating agent for a vapor-deposited film of the present invention is characterized in that it contains a carbamate resin (A), wherein the carbamate resin (A) is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), and the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2). The polycondensate of the polycarboxylic acid component (A1) and the polyol component (A2), that is, the polyester (A3), is not particularly limited and can be obtained by a known and conventional method (polycondensation reaction).

[0048] (Acid value of polyester polyol (polyester (A3))

[0049] The acid value of the polyester polyol is preferably 0 to 5 mgKOH / g, more preferably 0 to 1 mgKOH / g, from the viewpoint of obtaining a hydroxyl-terminated polyester. By setting the acid value within the above range, a hydroxyl-terminated polyester can be obtained, and then the molecular weight can be well increased by reaction with a diisocyanate (A5), which is effective.

[0050] (Hydroxyl value of polyester polyol (polyester (A3))

[0051] The hydroxyl value of the polyester polyol is preferably 20 to 400 mgKOH / g, and more preferably 40 to 250 mgKOH / g, from the viewpoint of obtaining excellent adhesion and gas barrier properties between the coating film and the vapor deposition surface. By making the hydroxyl value within the above range, the urethane resin (A) can exert good cohesive force after the subsequent reaction with the diisocyanate (A5), and exhibit excellent adhesion and gas barrier properties between the coating film and the vapor deposition surface, which is effective.

[0052] (Number average molecular weight (Mn) of polyester polyol (polyester (A3))

[0053] The number average molecular weight (Mn) of the polyester polyol (polyester (A3) is preferably 280 to 5600, more preferably 450 to 2800, from the viewpoint of obtaining excellent adhesion between the coating film and the vapor deposition surface and gas barrier properties. By setting the number average molecular weight (Mn) within the above range, it is effective to exhibit excellent adhesion between the coating film and the vapor deposition surface and gas barrier properties.

[0054] The blending ratio of the polyester (A3) is preferably 20 to 87 parts by mass, more preferably 42 to 81 parts by mass, based on 100 parts by mass of the urethane resin (A), from the viewpoint of improving the gas barrier properties of the resulting coating film and forming a uniform coating film by improving film forming properties.

[0055] (Active hydrogen group-containing compound having a hydrophilic group (A4))

[0056] The coating agent for vapor deposition film of the present invention is characterized in that it contains a carbamate resin (A), wherein the carbamate resin (A) is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group and a diisocyanate (A5), and the polyester (A3) is a condensation product of a polycarboxylic acid component (A1) and a polyol component (A2).

[0057] The active hydrogen group-containing compound (A4) having a hydrophilic group has a hydrophilic group, which can make the urethane resin (A) (particles) easily dispersed in the aqueous medium (B), and can contribute to improving the gas barrier properties and adhesion (adhesion to the substrate) of the resulting coating film, which is useful.

[0058] The above-mentioned active hydrogen group-containing compound (A4) containing a hydrophilic group is a compound containing a hydrophilic group such as a nonionic group or an ionic group and containing an active hydrogen group such as an amino group or a hydroxyl group. Specific examples thereof include active hydrogen group-containing compounds containing nonionic groups and active hydrogen group-containing compounds containing ionic groups.

[0059] As the aforementioned active hydrogen group-containing compound containing a nonionic group, for example, an active hydrogen group-containing compound containing a polyalkylene oxide group as a nonionic group can be listed, for example, polyoxyethylene glycol, single end-capped polyoxyethylene glycol, polyols containing polyoxyethylene side chains, etc. can be listed. In addition, as the aforementioned active hydrogen group-containing compound containing an ionic group, for example, an organic compound having an anionic group such as carboxylic acid, a cationic group such as a quaternary amine, two or more hydroxyl or amino active hydrogen groups, etc. can be listed. Among them, as the aforementioned active hydrogen group-containing compound (A4) containing a hydrophilic group, an organic compound having an anionic group (carboxyl group) of carboxylic acid and two or more hydroxyl groups at the same time has a carboxyl group, so that the carbamate resin (A) (particles) can be easily dispersed in the aqueous medium (B) without using an emulsifier, etc., which is preferred from the viewpoint of workability and preventing the emulsifier from seeping into the coating film.

[0060] As an organic compound having an anionic group (carboxyl group) of the aforementioned carboxylic acid and two or more hydroxyl groups at the same time, for example, polyhydroxyalkanoic acids such as 2,2-dimethylol acetic acid, 2,2-dimethylol lactic acid, 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid, 2,2-dimethylol butyric acid, and 2,2-dimethylol valeric acid can be listed, and 2,2-dimethylol propionic acid is more preferably listed. They can be used alone or in combination of two or more. Among them, from the viewpoint of obtaining a urethane resin with good water dispersion stability, it is preferred to neutralize part or all of the carboxylic acid using a basic compound or the like.

[0061] The blending ratio of the active hydrogen group-containing compound (A4) having a hydrophilic group is preferably 3 to 20 parts by mass, more preferably 4 to 10 parts by mass, based on 100 parts by mass of the urethane resin (A), from the viewpoint of obtaining good water dispersion stability.

[0062] (Diisocyanate (A5))

[0063] The coating agent for a vapor-deposited film of the present invention is characterized in that it contains a urethane resin (A), wherein the urethane resin (A) is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2). The diisocyanate (A5) forms a hard segment that is difficult for oxygen to permeate in the obtained urethane resin (A), and a coating film obtained using the obtained urethane resin (A) exhibits good gas barrier properties, which is useful.

[0064] Examples of the diisocyanate (A5) include toluene diisocyanate (TDI), diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, tetramethylxylylene diisocyanate, trimethylene diisocyanate, 1,2-propylene diisocyanate, and butylene diisocyanate. Acid ester, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, norbornane diisocyanate, etc., among which, from the viewpoint of improving the gas barrier property of the obtained coating film and forming a uniform coating film by improving the film forming property, toluene diisocyanate and isophorone diisocyanate are preferred, and toluene diisocyanate is more preferred. They can be used alone or in combination of two or more.

[0065] In the coating agent for deposited film of the present invention, preferably 50 to 100% by mass of toluene diisocyanate is contained relative to 100% by mass of the total amount of the diisocyanate (A5), more preferably 60 to 100% by mass, and further preferably 70 to 100% by mass. If it is within the above range, a hard segment that is not easily permeable to oxygen is formed in the obtained urethane resin (A), and the coated film exhibits good gas barrier properties, which is useful.

[0066] The blending ratio of the diisocyanate (A5) is preferably 10 to 50 parts by mass, more preferably 15 parts by mass or more and less than 40 parts by mass, in 100 parts by mass of the urethane resin (A), from the viewpoint of improving the gas barrier properties of the resulting coating film and forming a uniform coating film by improving film forming properties.

[0067] (Chain Extender (A6))

[0068] The coating agent for a vapor-deposited film of the present invention preferably contains the aforementioned urethane resin (A), which is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2), and the aforementioned composition further contains a chain extender (A6). By using the aforementioned chain extender (A6), the obtained urethane resin (A) exhibits a higher cohesive force, and the gas barrier properties of the obtained coating film can be improved, which is useful.

[0069] The chain extender (A6) can be used without particular limitation as long as it has two or more active groups capable of reacting with the isocyanate groups of the diisocyanate (A5), and generally, chain extenders having two hydroxyl groups or amino groups are mainly used.

[0070] Examples of the chain extender having two hydroxyl groups include aliphatic diols such as ethylene glycol, propylene glycol, and butanediol; aromatic diols such as benzyl alcohol and bishydroxyethoxybenzene; and diols such as ester diols such as neopentyl glycol hydroxypivalate. These can be used alone or in combination of two or more.

[0071] In addition, examples of the chain extender having two amino groups include aromatic diamines such as toluenediamine, xylylenediamine, and diphenylmethanediamine; aliphatic diamines such as ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3-propylenediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine; and alicyclic diamines such as 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropylidenecyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, and 1,3-bisaminomethylcyclohexane. These may be used alone or in combination of two or more.

[0072] The blending ratio of the chain extender (A6) is preferably 0 to 10 parts by mass, more preferably 0 to 8 parts by mass, based on 100 parts by mass of the urethane resin (A), from the viewpoint of adjusting the cohesive force of the urethane resin.

[0073] (Aqueous medium (B))

[0074] The coating agent for the vapor-deposited film of the present invention is characterized in that it contains an aqueous medium (B). By making the aforementioned vapor-deposited film coating agent contain an aqueous medium (B), a commonly used organic solvent is not used, so there is no problem of residual solvent, and no harmful organic solvent is released into the atmosphere, which is preferred.

[0075] The aqueous medium (B) is not particularly limited, and examples thereof include alcohols and ketones in addition to water. Examples of the alcohols include methanol, ethanol, isopropanol (isopropyl alcohol), butanol, 2-ethylhexanol, other alkanols (C5-38) and aliphatic unsaturated alcohols (C9-24), enols, 2-propylene-1-ol, alkadienol (alkadienol) (C6-8), 3,7-dimethyl-1,6-octadiene-3-ol, ethylene glycol, propylene glycol, glycerol, diethylene glycol, dipropylene glycol, etc. Examples of the ketones include acetone, methyl ethyl ketone, etc., among which water and / or isopropanol are preferred, and a mixed solvent of water and isopropanol is particularly preferred. These can be used alone or in combination of two or more.

[0076] The proportion of the aqueous medium (B) in 100 parts by mass of the coating composition is preferably 80 parts by mass or more, more preferably 80 to 90 parts by mass, from the viewpoint of promoting uniform formation of a coating film and increasing the drying rate of the aqueous medium.

[0077] (Curing agent (C))

[0078] The coating agent for the vapor-deposited film of the present invention preferably contains a curing agent (C) (cross-linking agent). By making the aforementioned vapor-deposited film coating agent contain a curing agent (C) (hereinafter sometimes referred to as a "cross-linking agent"), the aforementioned urethane resin (A) (particles) and the aforementioned curing agent (C) react, thereby, it is preferred from the viewpoint of improving the gas barrier properties, boiling resistance, and adhesion of the obtained coating film.

[0079] As the aforementioned curing agent (C), melamine crosslinking agent, carbodiimide crosslinking agent, water-dispersible polyisocyanate crosslinking agent, epoxy crosslinking agent, oxazoline crosslinking agent, aziridine crosslinking agent, etc. can be listed, wherein, from the viewpoint of gas barrier properties, adhesion and reaction speed of the crosslinking agent, at least one selected from the group consisting of melamine crosslinking agent, carbodiimide crosslinking agent and water-dispersible polyisocyanate crosslinking agent is preferred, and melamine crosslinking agent is more preferred. It should be noted that when using the aforementioned melamine crosslinking agent, in order to increase the crosslinking reaction speed, an acid catalyst for the use of the melamine crosslinking agent can be used. They can be used alone or in combination of two or more.

[0080] The blending ratio of the curing agent (C) is preferably 2 to 10 parts by mass, more preferably 3 to 7 parts by mass, based on 100 parts by mass of the urethane resin (A), from the viewpoint of ensuring good adhesion and gas barrier properties of the resulting coating film.

[0081] (Gas Capture Component)

[0082] In addition, the coating agent for the vapor-deposited film of the present invention may further add a material having a gas capture function as needed. As materials having an oxygen capture function, low molecular weight organic compounds that react with oxygen, such as hindered phenols, vitamin C, vitamin E, organic phosphorus compounds, gallic acid, pyrogallol, etc.; transition metal compounds of cobalt, manganese, nickel, iron, copper, etc., etc. As materials having a water vapor capture function, materials such as silica gel, zeolite, activated carbon, and calcium carbonate may be cited. In addition to these, a capture component of the target gas to be blocked may also be added.

[0083] (Other additives)

[0084] Furthermore, the coating agent for the vapor-deposited film of the present invention may be mixed with various additives as needed. As additives, for example, antioxidants, heat stabilizers, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, antiblocking agents, surfactants, dispersion stabilizers, colorants (pigments, dyes, etc.), fillers, colloidal silica, inorganic particles, inorganic oxide particles, crystal nucleating agents, thermoplastic resins with gas barrier properties, etc. can be listed. The mixing ratio of the above-mentioned additives is not particularly limited and is appropriately set according to the purpose and use.

[0085] (Gas barrier film)

[0086] The present invention relates to a gas barrier film obtained by applying the above-mentioned vapor-deposited film coating agent to a vapor-deposited film. The above-mentioned gas barrier film is excellent in gas barrier properties by using the above-mentioned vapor-deposited film coating agent, and is useful.

[0087] (Evaporated film)

[0088] The gas barrier film of the present invention improves the gas barrier properties of the vapor-deposited film, and various vapor-deposited films are used as the object to be coated with the aforementioned vapor-deposited film coating agent. The film coated with the aforementioned vapor-deposited film coating agent has better gas barrier properties than ordinary vapor-deposited films, and can therefore be used as a high gas barrier film.

[0089] (Type of vapor deposition layer)

[0090] The type of the vapor-deposited layer of the vapor-deposited film is not particularly limited as long as it can impart gas barrier properties. Currently, metal vapor deposition or metal oxide vapor deposition widely used for packaging purposes can be suitably exemplified. As metal vapor deposition, various metals can be exemplified, and aluminum, which is inexpensive and widely used, is particularly preferred.

[0091] In addition, as the aforementioned metal oxide, aluminum oxide (AlOx) and silicon oxide (SiOx) can be preferably exemplified as materials with high versatility. In addition, thin films on which various organic compounds and inorganic compounds are vapor-deposited; and materials on which various materials are vapor-deposited can also be used. As for the vapor deposition method, there is no particular limitation, and examples thereof include vacuum vapor deposition as a physical vapor deposition method and CVD as a chemical vapor deposition method.

[0092] Regarding the thickness of the aforementioned vapor-deposited layer, there is no particular limitation if the vapor-deposited layer alone can exhibit a certain gas barrier function, and a high barrier film can be further realized by providing a coating layer thereon. Among them, if the vapor-deposited layer is too thin, the contribution of the vapor-deposited layer to the gas barrier becomes smaller, and even if the coating agent of the present invention is used, it cannot exhibit a sufficient gas barrier function. Even if it is too thick, when the thickness is above a certain level, the barrier function is also reduced. Therefore, it is preferably 3 to 70 nm, and more preferably 5 to 60 nm. In addition, these vapor-deposited films may be pre-coated with an outer coating or a primer as protection for vapor deposition, or they may not be used. It should be noted that in a vapor-deposited film without a coating layer, the barrier function of the coating agent of the present invention can be fully exerted, so it is preferably used.

[0093] (Adhesive layer)

[0094] The adhesive layer is a cured coating of an adhesive. It is used to laminate a gas barrier film with a film having other functions such as heat sealability. The adhesive that can be used can be a solvent-based adhesive or a solvent-free adhesive, and there is no particular limitation.

[0095] (Type of film)

[0096] The film (substrate) using the coating agent for the vapor-deposited film of the present invention is not particularly limited, and the thermoplastic resin film can be appropriately selected according to the desired use. For example, as a food packaging application, polyolefin films such as polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyethylene film (LLDPE: linear low-density polyethylene film, HDPE: high-density polyethylene film), polypropylene film (CPP: unstretched polypropylene film, OPP: biaxially stretched polypropylene film) can be listed; polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, cycloolefin comonomer film, etc. These films can be preferably used with or without stretching treatment. The films that have been stretched have the advantages of easy coating operation and convenience of use due to dimensional stability and rigidity. In addition, for unstretched films, the dimensional stability, rigidity, and heat resistance of the substrate are poor, so there are many defects in the vapor-deposited layer and the gas barrier is unstable. Therefore, by using the aforementioned vapor-deposited film coating agent, there is an advantage of showing a significant effect on the enhancement of the barrier function.

[0097] In the present invention, in order to impart a higher barrier function, a barrier film containing a gas barrier layer of polyvinyl alcohol, ethylene-vinyl alcohol copolymer, vinylidene chloride, etc. may be used in combination to impart a higher barrier function.

[0098] (Coating method)

[0099] The coating method of the coating agent for the vapor-deposited film of the present invention is not particularly limited as long as it can be applied to the vapor-deposited surface of the vapor-deposited film. As a specific method, various coating methods such as roller coating and gravure coating can be illustrated. In addition, there is no particular limitation on the device used for coating.

[0100] (Coating film thickness)

[0101] The film thickness of the coating agent of the present invention is not particularly limited. For example, if it is 0.1 μm or more, the barrier enhancement effect can be exhibited. In consideration of the balance with drying properties, it is preferably in the range of 0.2 to 5 μm.

[0102] (Layer structure using coating agent)

[0103] The following structures are conceivable as the layer structure using the coating agent of the present invention: It is noted that good gas barrier properties can be imparted by applying the coating agent just above the vapor-deposited layer.

[0104] 1) Film + metal oxide vapor deposition layer + coating agent (coating) + adhesive layer + CPP film

[0105] 2) Film + metal oxide vapor deposition layer + coating agent (coating film) + ink + adhesive layer + CPP film

[0106] 3) Film + metal deposition layer + coating agent (coating) + adhesive layer + CPP film

[0107] 4) Film + metal deposition layer + coating agent (coating film) + ink + adhesive layer + CPP film

[0108] (Types of gas components that can block transmission)

[0109] Examples of gases that can be blocked by the gas barrier film obtained using the coating agent of the present invention include, in addition to oxygen and water vapor, inert gases such as carbon dioxide, nitrogen, and argon, alcohol components such as methanol, ethanol, and propanol, phenols such as phenol and cresol, and aroma components including low molecular weight compounds, such as soy sauce, dressing, miso, limonene, menthol, methyl salicylate, coffee, cocoa shampoo, and conditioner.

[0110] (Packaging materials and other uses)

[0111] The present invention relates to a packaging material using the aforementioned gas barrier film. The coating agent of the present invention improves the water vapor and oxygen barrier properties of the vapor-deposited film and also has a high lamination strength, so it can be used for various packaging materials that require lamination operations. Furthermore, as other uses, it can be suitably used as long as it is an adhesive for protective films for solar cells, a coating agent for water vapor barrier substrates for display elements, a coating agent for electronic materials, a coating agent for building materials, a coating agent for industrial materials, and the like, which are intended to enhance the water vapor and oxygen barrier properties.

[0112] Example

[0113] Next, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, "part" and "%" are by mass unless otherwise specified.

[0114] (Acid value (AN) of polyester polyol (polyester))

[0115] The acid value (mgKOH / g) is measured by the acid value measuring method described in JIS-K0070.

[0116] (Hydroxy value (OHV) of polyester polyol (polyester))

[0117] The hydroxyl value (mgKOH / g) is measured by the hydroxyl value measuring method described in JIS-K0070.

[0118] (Number average molecular weight (Mn) of polyester polyol (polyester))

[0119] The number average molecular weight of the polyester polyol was calculated using the following formula.

[0120] Mn=2×56110 / (OHV+AN)

[0121] (Synthesis of PEs-1)

[0122] Into a polyester reaction vessel equipped with a stirrer, a nitrogen inlet pipe, a distillation pipe, a moisture separator, etc., 621 parts of phthalic anhydride, 380 parts of ethylene glycol and 0.05 parts of titanium tetraisopropoxide were added, and the mixture was slowly heated so that the temperature of the upper part of the distillation pipe did not exceed 100° C., and the internal temperature was maintained at 220° C. When the acid value reached 10 mgKOH / g or less, heating was continued at 100 torr under reduced pressure, and the esterification reaction was terminated when the acid value reached 1 mgKOH / g or less, thereby obtaining a polyester polyol (polyester) "PEs-1" having a number average molecular weight of 518 calculated based on the hydroxyl value.

[0123] Next, polyester polyols "PEs-2" to "PEs-8" were synthesized according to Table 1 in the same manner as for polyester polyol "PEs-1".

[0124] [Table 1]

[0125]

[0126] (Synthesis of urethane resin 1)

[0127] In a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser and a nitrogen inlet tube, 338 parts of the polyester polyol "PEs-1" obtained above, 74 parts of ethylene glycol, 88 parts of 2,2-dimethylol propionic acid (DMPA), and 600 parts of methyl ethyl ketone were added, and then 435 parts of toluene diisocyanate (TDI) were added, and the mixture was reacted at 75°C for 8 hours. Then, the mixture was cooled to 50°C, 66 parts of triethylamine were added, and after neutralization, 4200 parts of water were added and dissolved in water. After removing methyl ethyl ketone from the obtained transparent reaction product at 40 to 60°C under reduced pressure, water was added and the concentration was adjusted, thereby obtaining a stable urethane resin 1 having a non-volatile component of 23%.

[0128] Next, urethane resins 2 to 7 were synthesized according to Table 2 in the same manner as for urethane resin 1.

[0129] [Table 2]

[0130]

[0131] (Preparation of coating agent and production of barrier laminate film)

[0132] (Example 1)

[0133] A curing agent (crosslinking agent) and a catalyst were added to 100 parts of the urethane resin 1 obtained above according to Table 3, and the mixture was diluted with water and isopropyl alcohol (IPA) as an aqueous medium to prepare a uniform coating agent having a nonvolatile content of 15%.

[0134] Hereinafter, coating agents of Examples 2 to 9 and Comparative Examples 2 to 5 were prepared in the same manner as in Example 1 according to Tables 3 and 4. Comparative Example 1 is an example in which no coating agent is used, and Example 3 and the like are examples in which no curing agent or the like is used.

[0135] [Table 3]

[0136]

[0137] [Table 4]

[0138]

[0139] Here, the abbreviations related to the curing agent (crosslinking agent) and the catalyst in the above Tables 3 and 4 are exemplified below.

[0140] (Crosslinking agent)

[0141] XW3106: CYMEL XW3106 (melamine crosslinking agent) manufactured by Allnex

[0142] SV-02: Made by Nisshinbo Chemical Co., Ltd., CARBODILITE SV-02 (carbodiimide crosslinking agent)

[0143] V-02-L2: Made by Nisshinbo Chemical Co., Ltd., CARBODILITE V-02-L2 (carbodiimide crosslinking agent)

[0144] WT31-100: DURANATE WT31-100 (water-dispersible polyisocyanate) manufactured by Asahi Kasei Corporation

[0145] (catalyst)

[0146] NACURE2500: Made by KING INDUSTRIES, NACURE2500 (acid catalyst for melamine crosslinking agent)

[0147] Each coating agent obtained above was applied using a bar coater #4 at a coating amount of 0.5 g / m 2 The mixture was applied onto the vapor-deposited surface of an alumina-deposited PET film (Barrialox 1011HG#12 manufactured by Toray Film Processing Co., Ltd.) as a substrate in the form of (solid content), and placed in a dryer set at 150° C. for 1 minute to obtain a gas barrier film having a uniform coating layer (coated film).

[0148] Next, Dic Dry LX-703VL (DIC Graphics, solvent-based polyester polyol) and KR-90 (DIC Graphics, polyisocyanate crosslinking agent) were mixed at a mass ratio of 15 / 1 on the surface of the coating layer, and ethyl acetate was added so that the nonvolatile content was 30% as an adhesive.

[0149] Use a bar coater to coat at a coating amount of 3.0 g / m 2 The obtained adhesive was applied in a manner, and the solvent was volatilized by hot air at 80° C. using a dryer to form an adhesive layer.

[0150] Next, dry lamination was performed with CPP film ZK-207 (manufactured by Toray Industries, Ltd., 70 μm thick) at a temperature of 40°C, a pressure of 0.4 MPa, and a lamination speed of 40 m / min to obtain a laminated film. The laminated film was left to stand for 3 days in a dryer set at a temperature of 40°C to dry and cure, thereby obtaining a barrier laminated film for test evaluation.

[0151] (Normal oxygen permeability)

[0152] The obtained barrier laminate film was subjected to normal oxygen permeability measurement (cc / (m 2 ·day·atm)).

[0153] (Oxygen permeability after steaming treatment)

[0154] The obtained barrier laminate film was three-way sealed to prepare a bag filled with water, and then subjected to retort treatment at 121°C for 30 minutes. Thereafter, the oxygen permeability (cc / (m 2 ·day·atm)).

[0155] The oxygen permeability in normal state and after retort treatment is preferably 7cc / (m 2 ·day·atm) or less, more preferably 6cc / (m 2 ·day·atm) or less, more preferably 5cc / (m 2 ·day·atm).

[0156] (Normal lamination bond strength)

[0157] The obtained barrier laminate film was cut into pieces with a width of 15 mm along the coating direction, and the laminate films (between the adhesive layer and the coating layer) were peeled off by a 180-degree peeling method using a desktop material testing machine STB-1225L manufactured by A&D Corporation, with the atmosphere temperature set to 25°C and the peeling speed set to 300 mm / min. The tensile strength at this time was defined as the lamination strength (N / 15 mm).

[0158] (Lamination bond strength after retort treatment)

[0159] The obtained barrier laminate film was three-way sealed to prepare a bag filled with water, and then retorted at 121° C. for 30 minutes. The lamination adhesive strength (N / 15 mm) after retorting was measured in the same manner as the normal lamination adhesive strength.

[0160] The lamination adhesive strength in normal state and after retort treatment is preferably 1.0 N / 15 mm or more, more preferably 1.5 N / 15 mm or more, and even more preferably 2.5 N / 15 mm or more.

[0161] Tables 5 and 6 below show the evaluation results of the laminated films of Examples and Comparative Examples.

[0162] [Table 5]

[0163]

[0164] [Table 6]

[0165]

[0166] The evaluation results in Table 5 above confirmed that all Examples had low oxygen permeability in normal state and after retort treatment and excellent gas barrier properties. In addition, it was confirmed that all Examples showed high laminating strength and excellent adhesiveness.

[0167] On the other hand, it was confirmed that in Comparative Example 1, since the vapor-deposited layer did not have a coating layer, the oxygen permeability in the normal state and after the retort treatment was inferior to that of the Examples.

[0168] It was confirmed that in Comparative Examples 2 to 5, since no alkylene glycol having 2 to 6 carbon atoms was used as the raw material for preparing the coating agent, the polyester polyol structure had high hydrophilicity and was easily degraded by the retorting treatment, and therefore the oxygen permeability after the retorting treatment was significantly poor.

[0169] It can be confirmed that: in Comparative Example 3, diethylene glycol is used in the polyester polyol part, which has high hydrophilicity. Therefore, after the boiling treatment, the adhesion of the coating film is reduced. In addition, the mass ratio of toluene diisocyanate in the urethane resin is as high as 40% or more, forming a hard coating film. Therefore, delamination is confirmed after the boiling treatment, and the oxygen permeability and lamination strength cannot be measured. It is not at a practical level.

Claims

1. A coating agent for a vapor-deposited film, comprising a urethane resin (A) and an aqueous medium (B), The urethane resin (A) is a reaction product of a composition containing a polyester (A3), an active hydrogen group-containing compound (A4) having a hydrophilic group, and a diisocyanate (A5), wherein the polyester (A3) is a polycondensate of a polycarboxylic acid component (A1) and a polyol component (A2). The urethane resin (A) has an ester skeleton derived from the polyester (A3), The polycarboxylic acid (A1) contains 10 to 100% by mass of at least one aromatic dicarboxylic acid or anhydride thereof, based on 100% by mass of the total amount of the polycarboxylic acid (A1). The polyol component (A2) contains an alkylene glycol having 2 to 6 carbon atoms.

2. The coating agent for a vapor-deposited film according to claim 1, wherein The composition further contains a chain extender (A6). The coating agent for a vapor-deposited thin film according to claim 1 , comprising a curing agent (C).

4. The coating agent for a vapor-deposited thin film according to claim 1, wherein The toluene diisocyanate is contained in an amount of 50 to 100% by mass based on 100% by mass of the total amount of the diisocyanate (A5).

5. The coating agent for a vapor-deposited film according to claim 1, wherein The aqueous medium (B) is water and / or isopropanol.

6. The coating agent for a vapor-deposited thin film according to claim 3, wherein The curing agent (C) is at least one selected from the group consisting of a melamine crosslinking agent, a carbodiimide crosslinking agent, and a water-dispersible polyisocyanate crosslinking agent. 7 . A gas barrier film obtained by applying the coating agent for a vapor-deposited film according to claim 1 to a vapor-deposited film.

8. A packaging material using the gas barrier film according to claim 7.

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