Release film and laminate

Abstract

To provide a release film that has high rigidity and excellent releasability and is intended to protect an exterior film, particularly a decorative film intended for automobiles.SOLUTION: A release film is composed of a base material layer including polyacetal resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a release film and a laminate. [Background technology]

[0002] Films such as resin-based films are used for applications such as application (e.g., exterior, repair) or packaging, and are particularly used as decorative films for automobiles. Such films are protected on one side (e.g., the application surface) or both sides with a release film for storage, distribution, application, packaging, etc., and the release film is peeled off when the film is applied or used for packaging, etc.

[0003] In particular, as a release film for decorative films for automobiles, a multilayer structure film has been proposed in which an easily peelable layer or a release agent is combined with a base layer that has rigidity but low peelability (Patent Documents 1 to 3).

[0004] Such multilayer structure films have the problem of increasing the number of manufacturing steps and manufacturing costs, but if a film that combines rigidity and releasability with only the base layer is used as the release film, it is expected that the number of manufacturing steps and manufacturing costs can be reduced. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6999405 [Patent Document 2] Japanese Patent Publication No. 2023-80853 [Patent Document 3] Japanese Patent Application Publication No. 2023-74354 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the present invention, it is possible to provide a release film that has high rigidity and excellent releasability and is used to protect exterior films, particularly decorative films for automobiles. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the inventors have found that a film using a polyacetal resin as a substrate layer has excellent rigidity and releasability and can be used as a release film without combining it with an easy-peel layer or a release agent, and have thus completed the present invention.

[0008] That is, the present invention is as follows. [1] A release film comprising a substrate layer containing a polyacetal resin. [2] The release film according to [1], which is composed only of the substrate layer. [3] The release film according to [1] or [2], wherein the polyacetal resin has a melt flow rate of 0.5 to 50 g / 10 min. [4] The release film according to any one of [1] to [3], wherein the base layer contains a heat stabilizer, and the heat stabilizer has a median diameter (D50) of 50 μm or less. [5] The release film according to any one of [1] to [4], wherein the polyacetal resin is a copolymer and the content of comonomer in the polyacetal resin is an amount equivalent to 2.0 mol % or less per 1 mol of trioxane. [6] The release film according to any one of [1] to [5], which is a release film for a decorative film for automobiles. [7] The release film according to [6], wherein the decorative film for automobiles is a decorative film for automobiles of the type that requires application of adhesive immediately before application. [8] The release film according to any one of [1] to [7], which is a release film for a film containing metal pigment particles. [9] A laminate comprising a main body film and the release film according to any one of [1] to [8] laminated on at least one surface of the main body film.

[10] The laminate according to [9], wherein after the main body film is peeled off from the laminate, the Ra of the surface of the release film that was in contact with the main body film is 0.4 μm or less.

[11] A method for producing a laminate according to [9] or

[10] , wherein components constituting the main body film are laminated on one side of the release film.

[12] A method for manufacturing a decorative film, comprising: (1) A process for obtaining a release film by extrusion molding polyacetal resin (2) A step of coating a decorative layer or a top coat layer on the smooth surface of the release film obtained in (1) to obtain a laminate A. (3) A process of coating the release film obtained in (1) with an adhesive layer and attaching a release film thereon to obtain laminate B. (4) removing the release film on one side of the laminate B, and then bonding the laminate A and the laminate B together; A manufacturing method for decorative film.

[13] Use of polyacetal resin as a single layer release film (substrate layer). [Effects of the Invention]

[0009] The release film of the present invention has high rigidity and excellent releasability, and can be suitably used as a release film for protecting exterior films, particularly decorative films for automobiles. DETAILED DESCRIPTION OF THE INVENTION

[0010] The contents of the present invention will be explained below.

[0011] (Release film) The release film of the present invention comprises a substrate layer containing a polyacetal resin. The term "release film" refers to a film that is laminated on one or both sides of a main film (e.g., a film for application or packaging) to protect the main film for storage, distribution, application, packaging, etc., and is peeled from the main film when the main film is used (e.g., application or packaging).

[0012] <Polyacetal resin> The polyacetal resin used in the present invention is not particularly limited, and known polyacetal resins may be used. Examples include polyacetal homopolymers consisting essentially of oxymethylene units, obtained by homopolymerizing formaldehyde monomer or cyclic oligomers of formaldehyde such as its trimer (trioxane) or tetraoxane, and polyacetal copolymers obtained by copolymerizing formaldehyde monomer or cyclic oligomers of formaldehyde such as its trimer (trioxane) or tetraoxane with cyclic ethers or cyclic formals, such as ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolane, 1,4-butanediol formal, glycols, and cyclic formals of diglycols.

[0013] Among the polyacetal copolymers, preferred comonomers are 1,3-dioxolane and 1,4-butanediol formal, from the viewpoint of achieving a better balance of rigidity, toughness, and heat resistance. Furthermore, as the polyacetal copolymer, a branched polyacetal copolymer having branches obtained by copolymerizing a monofunctional glycidyl ether, or a crosslinked polyacetal copolymer having a crosslinked structure obtained by copolymerizing a polyfunctional glycidyl ether can also be used. Furthermore, block-type polyacetal homopolymers having block components obtained by polymerizing formaldehyde monomers or cyclic oligomers of formaldehyde in the presence of a compound having functional groups such as hydroxyl groups at both or one end, for example, polyalkylene glycol, and block-type polyacetal copolymers having block components obtained by copolymerizing formaldehyde monomers or cyclic oligomers of formaldehyde, such as its trimer (trioxane) or tetramer (tetraoxane), with a cyclic ether or cyclic formal in the presence of a compound having functional groups such as hydroxyl groups at both or one end, for example, hydrogenated polybutadiene glycol, can also be used.

[0014] The comonomer content in the polyacetal resin is preferably an amount equivalent to 2.0 mol% or less, more preferably an amount equivalent to 1.2 mol% or less, even more preferably an amount equivalent to 0.1 mol% or less, and particularly preferably an amount equivalent to 0 mol% (i.e., the polyacetal resin is a polyacetal homopolymer) relative to 1 mol of trioxane. If the comonomer content is within the above range, the polyacetal resin itself has a high degree of crystallinity, and the resulting sheet also has high rigidity.

[0015] In the present invention, the above polyacetal resins may be used alone or in a mixture of two or more kinds. The method for producing the polyacetal resin is not particularly limited, and a known method for producing a polyacetal resin may be used. For example, in the case of a polyacetal homopolymer, a method for producing the polyacetal resin includes introducing high-purity formaldehyde into an organic solvent containing a basic polymerization catalyst such as an organic amine, an organic or inorganic tin compound, or a metal hydroxide to polymerize the polymer, filtering the polymer, and then heating the polymer in acetic anhydride in the presence of sodium acetate to acetylate the polymer terminals.

[0016] In addition, examples of a method for producing polyacetal resin of polyacetal copolymer include a method in which a mixture of high-purity trioxane, copolymerization components such as ethylene oxide, 1,3-dioxolane, and 1,4-butanediol formal, and a chain transfer agent for molecular weight control are homogeneously mixed in an organic solvent such as cyclohexane, and a compound such as a Lewis acid, such as boron trifluoride diethyl ether complex, is used as the polymerization catalyst, and these components are introduced into a twin-screw self-cleaning reactor to cause cationic polymerization, followed by deactivating the polymerization catalyst and stabilizing the polymer end groups. Formic acid, methanol, and water present in trioxane, 1,3-dioxolane, and 1,4-butanediol significantly reduce the thermal stability of the resulting polymer, causing decomposition of the polymer during sheet processing and making continuous production difficult. Therefore, they must be removed as much as possible before the polymerization reaction, and the amount of impurities present in the total monomers should be 30 ppm or less, preferably 20 ppm or less, and more preferably 10 ppm or less.

[0017] The polymerization reactor is preferably a reactor in which trioxane, copolymerization components, a chain transfer agent for molecular weight control, and a catalyst are introduced into a self-cleaning extrusion kneader such as a co-kneader, a twin-screw continuous extrusion kneader, or a twin-screw paddle continuous mixer, and then bulk polymerization is carried out, followed by the addition of a quaternary ammonium compound such as choline hydroxide formate to decompose and remove unstable terminals.

[0018] The melt flow rate (unit: g / 10 min) of a polyacetal resin is a value that serves as an index of molecular weight and can be appropriately selected from the viewpoints of resin stability, film productivity, etc. The melt flow rate is preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1.0 or more, and particularly preferably 1.6 or more. It is also preferably 50 or less, more preferably 30 or less, even more preferably 15 or less, and particularly preferably 5 or less.

[0019] The content of the polyacetal resin in the release film of the present invention is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more.

[0020] <Other ingredients> The release film (substrate layer) of the present invention may contain components other than the polyacetal resin (hereinafter referred to as "other components"). Examples of the "other components" that the release film of the present invention may contain include a heat stabilizer, a weather (light) resistance stabilizer, a release agent, etc., which may be used alone or in combination.

[0021] The release film (substrate layer) of the present invention preferably contains a heat stabilizer. Examples of heat stabilizers include soluble heat stabilizers (e.g., low-molecular-weight compounds) and particulate heat stabilizers (e.g., polymers). When the heat stabilizer is a particulate heat stabilizer, the melting point of the particulate heat stabilizer is preferably 190°C or less, more preferably 175°C or less, and even more preferably 160°C or less. The median diameter (D50) is preferably 50 μm or less, more preferably 25 μm or less, even more preferably 10 μm or less, and particularly preferably 5 μm or less. Examples of such heat stabilizers include antioxidants, scavengers for formaldehyde and formic acid, etc.

[0022] As the heat stabilizer, antioxidants, formaldehyde or formic acid scavengers, or a combination of these are effective. As the antioxidant, hindered phenol-based antioxidants are preferred, such as n-octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)-propionate, n-octadecyl-3-(3'-methyl-5'-t-butyl-4'-hydroxyphenyl)-propionate, n-tetradecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)-propionate, 1,6-hexanediol-bis(2-methyl-4-hydroxyphenyl)propionate, and the like. bis-(3-(3',5'-di-t-butyl-4'-hydroxyphenyl)-propionate), 1,4-butanediol-bis-(3-(3',5'-di-t-butyl-4'-hydroxyphenyl)-propionate), triethylene glycol-bis-(3-(3'-t-butyl-5'-methyl-4'-hydroxyphenyl)-propionate), tetrakis-(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate), N,N'-bis-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionylhexamethylenediamine, N,N'-tetramethylenebis-3-(3'-methyl-5'-t-butyl)propionatemethane, 3,9-bis(2-(3-(3'-t-butyl-4'-hydroxy-5'-methylphenyl)propionyloxy)-1,1-dimethylethyl)2,4,8,10-tetraoxaspiro(5,5)undecane, N,N'-bis-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionylhexamethylenediamine, N,N'-tetramethylenebis-3-(3'-methyl-5'-t-butyl 4'-hydroxyphenyl)propionyldiamine, N,N'-bis-(3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionyl)hydrazine, N-salicyloyl-N'-salicylidenehydrazine, 3-(N-salicyloyl)amino-1,2,4-triazole, N,N'-bis(2-(3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionyloxy)ethyl)oxyamide, and the like. Among these hindered phenol-based antioxidants, triethylene glycol-bis-(3-(3'-t-butyl-5'-methyl-4'-hydroxyphenyl)-propionate) and tetrakis-(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate methane are preferred.

[0023] Examples of scavengers for formaldehyde and formic acid include (a) compounds and polymers containing formaldehyde-reactive nitrogen, and (b) hydroxides, inorganic acid salts, carboxylates and alkoxides of alkali metals or alkaline earth metals. (a) Examples of compounds containing formaldehyde-reactive nitrogen include (1) dicyandiamide, (2) amino-substituted triazines, and (3) co-condensates of amino-substituted triazines and formaldehyde. (2) Examples of amino-substituted triazines include guanamine (2,4-diamino-sym-triazine), melamine (2,4,6-triamino-sym-triazine), N-butylmelamine, N-phenylmelamine, N,N-diphenylmelamine, N,N-diallylmelamine, N,N',N''-triphenylmelamine, N-methylolmelamine, N,N'-dimethylolmelamine, N,N',N''-trimethylolmelamine, benzoguanamine (2,4-diamino-6-phenyl-sym-triazine), 2,4-diamino-6-methyl-sym-triazine, and 2 Examples of amino-substituted triazines include 2,4-diamino-6-butyl-sym-triazine, 2,4-diamino-6-benzyloxy-sym-triazine, 2,4-diamino-6-butoxy-sym-triazine, 2,4-diamino-6-cyclohexyl-sym-triazine, 2,4-diamino-6-chloro-sym-triazine, 2,4-diamino-6-mercapto-sym-triazine, 2,4-dioxy-6-amino-sym-triazine (Amerite), 2-oxy-4,6-diamino-sym-triazine (Amerin), and N,N,N',N'-tetracyanoethylbenzoguanamine. (3) Examples of co-condensation products of amino-substituted triazines and formaldehyde include melamine-formaldehyde polycondensates. Among these, dicyandiamide, melamine, and melamine-formaldehyde polycondensates are preferred.

[0024] Furthermore, (i) polymers having formaldehyde-reactive nitrogen groups may include (1) polyamide resins, (2) polymers obtained by polymerizing acrylamide and its derivatives or acrylamide and its derivatives with other vinyl monomers in the presence of a metal alcoholate, (3) polymers obtained by polymerizing acrylamide and its derivatives or acrylamide and its derivatives with other vinyl monomers in the presence of a radical polymerization initiator, and (4) polymers containing nitrogen groups such as amines, amides, ureas, and urethanes. Examples of polyamide resins (1) include nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 12, and copolymers thereof, such as nylon 6 / 6-6, nylon 6 / 6-6 / 6-10, and nylon 6 / 6-12. Examples of (2) polymers obtained by polymerizing acrylamide and its derivatives or acrylamide and its derivatives with other vinyl monomers in the presence of a metal alcoholate include poly-β-alanine copolymers. These polymers can be produced by the methods described in JP-B-6-12259, JP-B-5-87096, JP-B-5-47568 and JP-A-3-234729. (3) Polymers obtained by polymerizing acrylamide and its derivatives or acrylamide and its derivatives with other vinyl monomers in the presence of a radical polymerization initiator can be produced by the method described in JP-A-3-28260.

[0025] (b) Examples of hydroxides, inorganic acid salts, carboxylates, and alkoxides of alkali metals or alkaline earth metals include hydroxides, carbonates, phosphates, silicates, borates, and carboxylates of sodium, potassium, magnesium, calcium, barium, etc. of these metals. The carboxylic acid of the carboxylate salt is a saturated or unsaturated aliphatic carboxylic acid having 10 to 36 carbon atoms, etc., and these carboxylic acids may be substituted with a hydroxyl group. Examples of saturated aliphatic carboxylic acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, and ceroplastic acid. Examples of unsaturated aliphatic carboxylic acids include undecylenic acid, oleic acid, elaidic acid, cetoleic acid, erucic acid, brassidic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, and stearic acid. Examples of the alkoxide include methoxides and ethoxides of the above metals.

[0026] As the weathering (light) stabilizer, (i) benzotriazole-based substances, (ii) oxalic acid anilide-based substances, and (iii) hindered amine-based substances are preferred. (i) Benzotriazole-based substances include, for example, 2-(2'-hydroxy-5'-methyl-phenyl)benzotriazole, 2-[2'-hydroxy-3,5-di-t-butyl-phenyl)benzotriazole, 2-[2'-hydroxy-3,5-di-isoamyl-phenyl)benzotriazole, 2-[2'-hydroxy-3,5-bis-(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, and 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, and preferably 2-[2'-hydroxy-3,5-bis-(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole and 2-[2'-hydroxy-3,5-di-t-butyl-phenyl)benzotriazole.

[0027] (b) Examples of oxalic acid anilide substances include 2-ethoxy-2'-ethyloxalic acid bisanilide, 2-ethoxy-5-t-butyl-2'-ethyloxalic acid bisanilide, 2-ethoxy-3'-dodecyloxalic acid bisanilide, etc. These substances may be used alone or in combination of two or more.

[0028] (c) Examples of hindered amine substances include 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(phenylacetoxy)-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, xyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-(ethylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(cyclohexylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(phenylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, bis(2,2,6,6-tetramethyl-4-piperidine)-carbonate, bis(2, 2,6,6-tetramethyl-4-piperidyl)-oxalate, bis(2,2,6,6-tetramethyl-4-piperidyl)-malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)-sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)-adipate, bis(2,2,6,6-tetramethyl-4-piperidyl)-terephthalate, 1,2-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-ethane, α,α'-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-p-oxy Examples of the bis(2,2,6,6-tetramethyl-4-piperidyl)trilen-2,4-dicarbamate include bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene-1,6-dicarbamate, tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,5-tricarboxylate, and tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,4-tricarboxylate, and preferably bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.The above hindered amine-based substances may be used alone or in combination of two or more thereof, and the combination of the above benzotriazole-based substance or oxalic acid anilide-based substance with a hindered amine-based substance is most preferred.

[0029] Examples of the release agent include alcohol, fatty acid, ester of alcohol and fatty acid, ester of alcohol and dicarboxylic acid, fatty acid amide, metal soap, polyoxyalkylene glycol, etc. Examples of the alcohol include olefin compounds with an average degree of polymerization of 10 to 500, and silicone oil. Examples of the alcohol include monohydric alcohols and polyhydric alcohols, and examples of the monohydric alcohols include octyl alcohol, capryl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, hebutadecyl alcohol, stearyl alcohol, oleyl alcohol, nonadecyl alcohol, eicosyl alcohol, behenyl alcohol, ceryl alcohol, melissyl alcohol, 2-hexyldecanol, 2-octyldodecanol, 2-decyltetradecanol, and unilin alcohol. The polyhydric alcohol is a polyhydric alcohol containing 2 to 6 carbon atoms, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol, hexanediol, glycerin, diglycerin, triglycerin, threitol, erythritol, pentaerythritol, arabitol, ribitol, xylitol, sorbite, sorbitan, sorbitol, and mannitol. Examples of fatty acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, araginic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, ceroplastic acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, erucic acid, brassidic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearic acid, and naturally occurring fatty acids containing such components, or mixtures thereof. These fatty acids may be substituted with a hydroxy group.

[0030] Esters of alcohols and fatty acids include fatty acid esters derived from fatty acids selected from palmitic acid, stearic acid, behenic acid, and montanic acid, and polyhydric alcohols selected from glycerin, pentaerythritol, sorbitan, and sorbitol. These fatty acid ester compounds may or may not have hydroxyl groups. There are no limitations on the type of hydroxyl group. For example, they may be monoesters, diesters, or triesters. The hydroxyl groups may also be blocked with boric acid or the like.Examples of preferred fatty acid esters include glycerin monopalmitate, glycerin dipalmitate, glycerin tripalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, glycerin monobehenate, glycerin dibehenate, glycerin tribehenate, glycerin monomontanate, glycerin dimontanate, glycerin trimontanate, pentaerythritol monopalmitate, pentaerythritol dipalmitate, pentaerythritol tripalmitate, pentaerythritol tetrapalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, pentaerythritol monobehenate, pentaerythritol dibehenate, pentaerythritol tribehenate, pentaerythritol tetrabe ... Sorbitol monomontanate, pentaerythritol dimontanate, pentaerythritol trimontanate, pentaerythritol tetramontanate, sorbitan monopalmitate, sorbitan dipalmitate, sorbitan tripalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monobehenate, sorbitan dibehenate, sorbitan tribehenate, sorbitan monomontanate sorbitol monobehenate, sorbitol dimontanate, sorbitol trimontanate, sorbitol monopalmitate, sorbitol dipalmitate, sorbitol tripalmitate, sorbitol monostearate, sorbitol distearate, sorbitol tristearate, sorbitol monobehenate, sorbitol dibehenate, sorbitol tribehenate, sorbitol monomontanate, sorbitol dimontanate, and sorbitol trimontanate. Also included are borate esters of glycerin mono fatty acid esters as aliphatic ester compounds in which the hydroxyl groups are blocked with boric acid or the like.

[0031] Esters of alcohols and dicarboxylic acids include monoesters and diesters of saturated or unsaturated alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, n-amyl alcohol, 2-pentanol, n-heptyl alcohol, n-octyl alcohol, n-nonyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and behenyl alcohol, with dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, brassicic acid, maleic acid, fumaric acid, and glutaconic acid. Fatty acid amides include fatty acid amide compounds composed of a C16 or higher aliphatic carboxylic acid and an aliphatic amine or aliphatic diamine.

[0032] Examples of carboxylic acids constituting such aliphatic amides include palmitic acid, isopalmitic acid, stearic acid, isostearic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, melissic acid, lacteric acid, cetoleic acid, and erucic acid. Examples of amines and diamines include ammonia and ethylenediamine. Examples of such amide compounds include stearylamide, palmitylamide, oleylamide, methylenebisstearamide, ethylenebisstearamide, and ethylenebisoleylamide. Examples of metal soaps include zinc stearate, calcium stearate, and magnesium stearate. Examples of polyoxyalkylene glycols include polycondensates of alkylene glycol as a monomer, such as polyethylene glycol, polypropylene glycol, and polyethylene glycol / polypropylene glycol block polymers. The preferred range of polymerization moles for these is 5 to 1,000, and more preferably 10 to 500.

[0033] The second group is an ether compound of the first group with an aliphatic alcohol. Examples include polyethylene glycol oleyl ether (5-50 moles of ethylene oxide polymerization), polyethylene glycol cetyl ether (5-20 moles of ethylene oxide polymerization), polyethylene glycol stearyl ether (5-30 moles of ethylene oxide polymerization), polyethylene glycol lauryl ether (5-30 moles of ethylene oxide polymerization), polyethylene glycol tridecyl ether (5-30 moles of ethylene oxide polymerization), polyethylene glycol nonylphenyl ether (2-100 moles of ethylene oxide polymerization), and polyethylene glycol octylphenyl ether (4-50 moles of ethylene oxide polymerization). The third group is an ester compound of the first group with a higher fatty acid. Examples include polyethylene glycol monolaurate (2-30 moles of ethylene oxide polymerization), polyethylene glycol monostearate (2-50 moles of ethylene oxide polymerization), and polyethylene glycol monooleate (2-10 moles of ethylene oxide polymerization).

[0034] The olefin compound having an average degree of polymerization of 10 to 500 is a compound represented by the following general formula. (CH2CR 1 R 2 ) n [In the formula, R 1 , R 2 is selected from hydrogen, an alkyl group, an aryl group, and an ether group, and may be the same or different. n is the average degree of polymerization and is 10 to 500. Examples of alkyl groups include ethyl, propyl, butyl, hexyl, octyl, decyl, lauryl, cetyl, and stearyl groups, and examples of aryl groups include phenyl, p-butylphenyl, p-octylphenyl, p-nonylphenyl, benzyl, p-butylbenzyl, tolyl, and xylyl groups. Examples of ether groups include ethyl ether, propyl ether, and butyl ether groups. Specific examples of monomers constituting olefin compounds include olefin monomers such as ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-hexene, 2,3-dimethyl-2-butene, 1-heptene, 1-octene, 1-nonene, and 1-decene, as well as diolefin monomers such as allene, 1,2-butadiene, 1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, 1,5-hexadiene, and cyclopentadiene. Compounds obtained by copolymerizing two or more of these olefin monomers or diolefin monomers may also be used. When the olefin compound is a compound obtained by polymerizing a diolefin monomer, it is preferable to use an olefin compound in which the carbon-carbon unsaturated bonds have been minimized using a conventional hydrogenation method in order to improve thermal stability.

[0035] The content of the above components in the release film (substrate layer) of the present invention is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0% by mass.

[0036] On the other hand, it is preferable that the release film (substrate layer) of the present invention does not contain the following components or that the content thereof is as small as possible.

[0037] The release film (substrate layer) of the present invention preferably contains as little or as little components as possible other than the polyacetal resin used as the easy-peel layer or release agent, such as silicon-containing compounds and PTFE-containing compounds.

[0038] <Base material layer> The "substrate layer" refers to the layer that forms the base of the release film. The release film of the present invention is preferably a single-layer release film composed only of a substrate layer containing a polyacetal resin. Since the polyacetal resin itself has releasability, the release film of the present invention can be one that does not include other components that impart releasability, such as an easy-peel layer or a release agent. By having the release film of the present invention composed only of a substrate layer, the number of manufacturing steps and manufacturing costs can be reduced.

[0039] <Release film size, manufacturing method, etc.> The thickness of the release film of the present invention is not particularly limited, but is preferably 30 μm or more, more preferably 50 μm or more, and preferably 200 μm or less, more preferably 100 μm or less. The method for producing the release film of the present invention is not particularly limited, but may be, for example, twin-screw extrusion molding, uniaxial extrusion molding, or biaxial or uniaxial stretching. The release film of the present invention may or may not be stretched. The release film may also be molded into a shape that matches the desired shape of the main body film, thereby serving to retain the shape of the main body film.

[0040] In a method for forming a polyacetal resin film, first, as described above, a polyacetal resin composition is melt-kneaded in a single-screw or twin-screw extruder to produce pellets of the polyacetal resin composition. Then, the pellets are melted in a single-screw or twin-screw extruder, <1> Casting method: A method in which a molten polyacetal resin composition is supplied between a forming roller and a metal or rubber forming drum, and a sheet is continuously formed by the narrow pressure between the forming roller and the forming drum. <2> Sleeve touch type: A method in which the molten polyacetal resin composition is supplied and poured between a rotating forming roller and a cylindrical forming drum (sleeve) made of a thin, flexible pipe in the radial direction that rotates while contacting the forming roller in an arc shape along part of the outer circumferential surface of the forming roller, and a sheet is continuously formed by the narrow pressure between the forming roller and the forming drum. However, in order to fully exert the effects of the present invention, <1> The molding method of the above is preferred. As for molding conditions, the temperature of the molding roller is preferably in the range of 60°C to the crystallization onset temperature of the polyacetal resin composition. Within this range, a polyacetal resin sheet having excellent releasability between the molding roller and the polyacetal resin composition and excellent thickness uniformity can be obtained. More preferably, the temperature is in the range of 80°C to the crystallization onset temperature of the polyacetal resin composition, and even more preferably, in the range of 100°C to the crystallization onset temperature of the polyacetal resin composition.

[0041] (Laminate) The laminate of the present invention comprises a main body film and the release film of the present invention laminated on at least one side of the main body film. The term "main body film" is not particularly limited as long as it is used as a film, but particularly refers to a film for application or packaging, such as a decorative film. The term "laminate" refers to a laminate film in which a release film is laminated to protect one side (e.g., the application side) or both sides of the main body film, and is in a form suitable for use in storage, distribution, application, etc. of the main body film.

[0042] The "main film" is not particularly limited, but examples thereof include films used for applications such as attachment (e.g., exterior, repair) or packaging, and in particular, decorative films (e.g., decorative films for automobiles). The main film may also be a type of film to which an adhesive is applied immediately before attachment (e.g., decorative films for automobiles). The material of the main film is not particularly limited, but may be, for example, a resin-based film. The main film may also contain a colorant (e.g., metal pigment particles) for decorative appearance. The shape of the metal pigment particles is not particularly limited, and examples include flake, flat, and plate shapes. From the viewpoint of obtaining good metallic luster, flake shapes are preferred. The material of the metal pigment particles is not particularly limited, but examples include metals such as aluminum, chromium, nickel, tin, titanium, indium, copper, gold, silver, and brass, as well as alloys or compounds containing such metals. From the viewpoint of metallic luster, aluminum is preferred.

[0043] If the surface of the release film that was in contact with the main film after the main film has been peeled from the laminate is smooth, the surface of the transferred main film will be smooth, and a main film with excellent appearance can be obtained. After the main film has been peeled from the laminate, the surface of the release film that was in contact with the main film preferably has an Ra of 0.4 μm or less, more preferably 0.25 μm or less, and even more preferably 0.1 μm or less. [Example]

[0044] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. Measurement and evaluation methods used in the examples and comparative examples are shown below.

[0045] (Polyacetal resin composition) (POM composition 1 (homopolymer)) POM composition 1 was prepared as follows. A 5-L jacketed tank polymerization reactor 1 equipped with a stirrer was filled with 2 L of n-hexane and equipped with a circulation line (inner diameter: 6 mm, length: 2.5 m). The n-hexane was circulated at 20 L / hr using a pump. 200 g / hr of dehydrated formaldehyde gas was directly fed into this circulation line. A catalyst (dimethyl distearyl ammonium acetate) was also fed into the circulation line immediately prior to the reactor. A chain transfer agent (acetic anhydride) was added to the hexane being fed to compensate for the loss of the polymerization slurry sent to the next step. The flow rate was adjusted to 0.13 to 0.52 g / hr. Polymerization was carried out at 58°C while continuously feeding the hexane. A polymerization slurry containing a crude polymer was obtained. The amounts of the polymerization catalyst and chain transfer agent were adjusted so that the melt flow rate of the polyacetal resin composition was the value shown in Table 1.

[0046] The resulting polymerized slurry was reacted in a 1:1 mixture of hexane and acetic anhydride at 140°C for 2 hours, and the molecular ends were acetylated to stabilize the polymer. The polymer was collected by filtration, reduced to a pressure of less than 2 mmHg, and dried in a vacuum dryer set at 80°C for 3 hours to obtain a polyacetal homopolymer powder.

[0047] Furthermore, 100 parts by mass of this powder, 0.2 parts by mass of Irganox 245 (manufactured by Ciba Specialty Chemicals Co., Ltd.) as a stabilizer, and 0.2 parts by mass of H-3 (manufactured by Asahi Kasei Finechem Co., Ltd.) were mixed in a Henschel mixer for 1 minute. The H-3 was pre-pulverized to a median diameter (D50) of 4 μm before mixing. The resulting mixture was then melt-kneaded at 24 amperes in a vented screw-type twin-screw extruder (BT-30, manufactured by Plastics Industry Co., Ltd., L / D=44) set at 200°C with a screw rotation speed of 100. From the time the raw materials were added until the pellets were collected, oxygen contamination was avoided as much as possible.

[0048] (POM composition 2 (homopolymer)) The amount of chain transfer agent for POM composition 1 in Example 1 was adjusted so that the MFR was 50 g / 10 min, thereby obtaining POM composition 2.

[0049] (POM composition 3 (homopolymer)) The amount of chain transfer agent for POM composition 1 of Example 1 was adjusted so that the MFR was 100 g / 10 min, thereby obtaining POM composition 3.

[0050] (POM composition 4 (homopolymer)) POM composition 4 was obtained by pulverizing POM composition 1 of Example 1 so that the median diameter (D50) of H-3 was 30 μm.

[0051] (POM Composition 5 (Homopolymer)) POM composition 5 was obtained by pulverizing POM composition 1 of Example 1 so that the median diameter (D50) of H-3 was 100 μm.

[0052] (POM composition 6 (homopolymer)) For POM composition 1 of Example 1, the heat stabilizer was a polyamide 6 / 66 / 610 terpolymer (manufactured by Asahi Kasei Corporation, product: NA900), and the mixture was pulverized to a median diameter (D50) of 40 μm to obtain POM composition 6.

[0053] (POM Composition 7 (Copolymer)) POM composition 7 was prepared as follows. First, the polymerization step was carried out as follows. A jacketed, self-cleaning, twin-screw paddle-type continuous mixer reactor (screw diameter 3 inches, length to diameter ratio (L / D) = 10) capable of passing a heat transfer medium was adjusted to 80°C. Trioxane as the main monomer was fed at 3750 g / hr, 1,3-dioxolane as the comonomer at 25 to 150 g / hr, and methylal as the chain transfer agent (all of which had been treated to reduce impurities) at 2.0 to 8.0 g / hr. These were then continuously fed into the continuous mixer reactor.

[0054] In addition, a 1 mass % cyclohexane solution of boron trifluoride di-n-butyl etherate was used as a polymerization catalyst. -5 The amounts of the polymerization catalyst and chain transfer agent were adjusted so that the melt flow rate of the polyacetal resin composition (P) would be the values ​​shown in Table 1.

[0055] The obtained polymerized flakes were pulverized, and then the pulverized material was added to a 1% aqueous solution of triethylamine and stirred to deactivate the polymerization catalyst. Thereafter, the 1% aqueous solution of triethylamine containing the polymerized flakes was filtered, washed, and dried in this order to obtain a crude polymer.

[0056] To 1 part by mass of the obtained crude polymer, triethyl(2-hydroxyethyl)ammonium formate was added as a quaternary ammonium compound in an amount equivalent to 20 ppm when converted to the amount of nitrogen using the following mathematical formula (i), and after uniform mixing, the mixture was dried at 120°C for 3 hours to obtain a dried polymer. Amount of quaternary ammonium compound added = P × 14 / Q (i) (In formula (i), P represents the concentration (ppm by mass) of the quaternary ammonium compound relative to the crude polymer, "14" represents the atomic weight of nitrogen, and Q represents the molecular weight of the quaternary ammonium compound.)

[0057] The resulting dry polymer was then subjected to an end-stabilization and granulation step. The dried polymer was added to the front section of a vented screw-type twin-screw extruder (BT-30, manufactured by Plastics Kogyo Co., Ltd., L / D=44, set temperature 200°C, rotation speed 80 rpm), and 0.5 parts by mass of water was further added per 100 parts by mass of the dried polymer. The average residence time was set to 1 minute, and polymer terminal stabilization was carried out while degassing under reduced pressure.

[0058] Next, 100 parts by mass of the above dry polymer was mixed in advance with 0.2 parts by mass of Irganox 245 (manufactured by Ciba Specialty Chemicals Co., Ltd.) and 0.2 parts by mass of H-3 (manufactured by Asahi Kasei Finechem Co., Ltd.) as stabilizers in a Henschel mixer for 1 minute. The resulting mixture was added from a side feeder located at the rear of the twin-screw extruder, and melt-kneaded at 24 amperes at a screw rotation speed of 100 rpm in a vented screw-type twin-screw extruder (manufactured by Plastics Industry Co., Ltd., BT-30, L / D = 44) set at 200 ° C. to obtain pellets of polyacetal copolymer (A-2). From the introduction of raw materials to the collection of pellets, operations were carried out while avoiding oxygen contamination as much as possible.

[0059] (PET resin) As the PET resin, PET resin pellets (grade name: TRN-RTJ) manufactured by Teijin Ltd. were used.

[0060] (Extrusion molding of release film) The pellets of the POM composition prepared above were melted in a single-screw extruder set at a cylinder temperature of 230°C, and the molten resin was fed into a gap between a rotating metal forming roller (temperature = 140°C) and a rotating rubber roller. The resin was continuously molded by the narrow pressure between these forming rollers to obtain a film (thickness 50 μm).

[0061] (Preparation of adhesive) A white adhesive 2 was prepared by uniformly mixing 16 parts by mass of Diferamine (trademark) MAU-#5000 and 84 parts by mass of MEK.

[0062] (Preparation of Coating Composition) (Clear Coating Composition) A clear coating composition was obtained by uniformly mixing 60 parts by mass of Kansai Paint (trademark) PG80 #026, 6 parts by mass of Kansai Paint (trademark) Rethan PG80 hardener, and 34 parts by mass of Kansai Paint (trademark) Rethan PG thinner.

[0063] (Black Coating Composition) A black coating composition was obtained by uniformly mixing 60 parts by mass of Kansai Paint (trademark) PG80 #400, 6 parts by mass of Kansai Paint (trademark) Rethan PG80 hardener, and 34 parts by mass of Kansai Paint (trademark) Rethan PG thinner.

[0064] (Metallic Coating Composition) A metallic coating composition was prepared by uniformly mixing 20 parts by mass of Toyal Shine (trademark) TS-408PM, which is a metal pigment particle, and 80 parts by mass of MEK.

[0065] Example 1 POM composition 1 shown in Table 1 was obtained by the above-mentioned method for producing a POM composition, and release film 1 was obtained by the method shown in the above-mentioned method for extrusion molding of a release film. The clear coating composition was coated onto the approximately smooth surface of release film 1 using a No. 8 Mayer bar coater, and then dried in an oven at approximately 100°C for approximately 1 minute to produce laminate A with a thickness of approximately 0.4 micrometers. Next, adhesive 1 was coated onto another release liner, Film Vina (trademark) 38E-0020 manufactured by Fujimori Kogyo Co., Ltd., and then dried in an oven at approximately 80°C for approximately 3 minutes and then in an oven at approximately 120°C for approximately 5 minutes to prepare an adhesive layer approximately 40 micrometers thick. Release film 1 was then laminated onto this adhesive layer using a heat lamination method to produce adhesive transfer film B. After removing the release liner of adhesive transfer film B, adhesive transfer film B was attached to the clear coating layer of laminate A via the adhesive layer by heat lamination to obtain a laminate.

[0066] Example 2 A laminate was obtained in the same manner as in Example 1, except that POM composition 2 was used.

[0067] (Comparative Example 1) A laminate was obtained in the same manner as in Example 1, except that POM composition 3 was used.

[0068] Example 3 A laminate was obtained in the same manner as in Example 1, except that POM composition 4 was used.

[0069] (Comparative Example 2) A laminate was obtained in the same manner as in Example 1, except that POM composition 5 was used.

[0070] Example 4 A laminate was obtained in the same manner as in Example 1, except that POM composition 6 was used.

[0071] Example 5 A laminate was obtained in the same manner as in Example 1, except that POM composition 7 was used.

[0072] Example 6 A laminate was obtained in the same manner as in Example 1, except that the black coating composition was used instead of the clear coating composition of Example 1.

[0073] Example 7 A laminate was obtained in the same manner as in Example 1, except that the metallic coating composition was used instead of the clear coating composition of Example 1.

[0074] (Comparative Example 3) A laminate was obtained in the same manner as in Example 1, except that a PET resin was used and the cylinder temperature of the extruder was set to 280°C.

[0075] Comparative Example 4 POM composition 1 was used as the resin forming the outer release layer, a hydrogenated random copolymer of 20% by weight of styrene and 80% by weight of butadiene (Dynaron R "4600P" (trade name) manufactured by JSR Corporation) was used as the resin forming the middle adhesive layer, and PP (FG3DG" (trade name) manufactured by Japan Polychem Corporation) was used as the resin forming the inner base layer. These were extruded into a cylindrical shape using a three-layer co-extrusion inflation method so that the outer layer was 50 μm thick, the middle layer was 10 μm thick, and the inner layer was 60 μm thick. Air was then introduced into the resulting cylindrical molten film to inflate it, and water was released from a sizing ring installed around the tubular molten film to cool and solidify it. The tubular molten film was then folded with pinch rolls, taken up, and both ends were cut open. The resulting film was then wound up to obtain a laminate.

[0076] [Evaluation method] (Film productivity) Those in which drowning occurred and film could not be produced successfully were rated as ×, those in which slight drowning occurred but film production was possible were rated as △, and those in which no drowning occurred and film production was possible were rated as ◯.

[0077] (Film appearance) In each 30cm square, if there were more than 10 pockmarks that could be visually determined, they were marked with an X, if there were more than 5 but less than 10, they were marked with a △, and if there were 5 or less, they were marked with a 〇. The standard for pockmarks that can be visually determined is 200μm or less.

[0078] (Film stiffness) In practical use, a certain degree of stiffness is required when applying the film. Films with insufficient stiffness were rated as ×, films that were practically usable but difficult to apply were rated as △, and films that were practically usable and had sufficient stiffness for application were rated as ◯.

[0079] (peelability) In practical use, cases where the peelability was good (easy to peel off, no traces left) were marked with a ◯, and cases where it was difficult to peel off (strong adhesion strength, peeling traces left, etc.) were marked with an X.

[0080] (Film surface smoothness) The surface roughness Ra of the release film on the side from which the main body film was peeled off was measured, and a value of 0.4 μm or less was evaluated as ◯, and a value of more than 0.4 μm was evaluated as ×.

[0081] (Suitability for single layer use) Films that could not fully function as a release film without a release layer were rated as x, and films that could fully function as a release film without a release layer were rated as ◯.

[0082] [Table 1] [Industrial Applicability]

[0083] The release film of the present invention has high rigidity and excellent releasability, and can be suitably used as a release film for protecting exterior films, particularly decorative films for automobiles.

Claims

1. A release film comprising a substrate layer containing a polyacetal resin.

2. The release film according to claim 1 , which is composed only of the substrate layer.

3. 2. The release film according to claim 1, wherein the polyacetal resin has a melt flow rate of 0.5 to 50 g / 10 min.

4. 2. The release film according to claim 1, wherein the base layer contains a heat stabilizer, and the heat stabilizer has a median diameter (D50) of 50 μm or less.

5. 2. The release film according to claim 1, wherein the polyacetal resin is a copolymer, and the content of the comonomer in the polyacetal resin is an amount corresponding to 2.0 mol % or less per mol of trioxane.

6. The release film according to claim 1, which is a release film for a decorative film for automobiles.

7. 7. The release film according to claim 6, wherein the decorative film for automobiles is a decorative film for automobiles of the type to which an adhesive is applied immediately before application.

8. The release film according to claim 1 , which is a release film for a film containing metal pigment particles.

9. A laminate comprising a main body film and the release film according to any one of claims 1 to 8 laminated on at least one surface of the main body film.

10. 10. The laminate according to claim 9, wherein after the main body film is peeled from the laminate, the surface of the release film that was in contact with the main body film has an Ra of 0.4 μm or less.

11. 10. A method for producing a laminate according to claim 9, wherein components constituting the main body film are laminated on one side of the release film.

12. A method for manufacturing a decorative film, (1) A process for obtaining a release film by extrusion molding a polyacetal resin (2) A step of coating a decorative layer or a top coat layer on the smooth surface of the release film obtained in (1) to obtain a laminate A. (3) A step of coating the release film obtained in (1) with an adhesive layer and attaching a release film thereon to obtain a laminate B. (4) A step of removing a release film on one side of the laminate B, and then bonding the laminate A and the laminate B together. A manufacturing method for decorative film.

13. Use of polyacetal resin as a single layer release film (base layer).

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