JP2009073058A - Mold release polyester film for rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold release film for a rubber which hardly causes increase of a release force and can be released from a rubber sheet with a low release force even after rubber cross-linking process, even if the rubber cross-linking process is performed in such a state that it is laminated on a rubber surface of a rubber molded body or a rubber laminated body such as a rubber sheet. <P>SOLUTION: The mold release polyester film for the rubber used for protecting the rubber layer has a mold release layer including a resin based binder (A), a polymer wax component (B), and an antistatic agent (C) on at least one side surface of the polyester film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a release polyester film for rubber, and more specifically, a release polyester film for rubber used by being laminated on a rubber sheet or rubber molded body surface of an uncrosslinked or semi-crosslinked rubber, The present invention relates to a release polyester film for rubber, which is excellent in peelability of a laminated polyester film even when a rubber is subjected to a crosslinking treatment after the release polyester film is laminated, and is suitably used for weighting and surface protection of a rubber surface.

  Rubber sheets and molded articles have excellent cushioning properties and stretchability, and are therefore used in a wide range of industrial fields. However, when used as a rubber sheet, the rubber is flexible, and if the surface is smooth, the sheet surface becomes sticky, so that it is difficult to wind up and the like, which may be a problem. Yes, depending on the application, it may be necessary to adjust the surface properties of the rubber sheet or rubber molded body.

  As a solution to this problem, a mat or embossed film or paper is laminated on the surface of the rubber sheet, and the surface shape of the film or paper used is transferred to the rubber surface to give fine irregularities on the rubber surface. A method of applying and optimizing the surface properties is adopted.

  On the other hand, there is also an application in which a rubber sheet or the like is attached to another article using the adhesiveness that is expressed by smoothing the rubber surface. However, even in this method of use, in the manufacturing process of rubber sheets and the like, there is a problem in handling similar to the above, and a solution is required.

  As a remedy for the above problem, for example, a method of laminating a film having a smooth surface on the surface of a rubber sheet or the like, that is, a method of protecting the rubber sheet surface with a so-called separate film is known.

  In the above method, generally, a method of laminating a separate film in a state in which a rubber sheet or the like is uncrosslinked or semi-crosslinked, and then a crosslinking treatment is employed. The film is peeled off. In general, it is known that rubber exhibits a cross-linking adhesion phenomenon at the time of cross-linking, so that the peelability of the separate film is reduced by the cross-linking treatment. As a separate film, the surface is usually made of a silicone compound or a fluorine compound. Processed so-called release films and release papers are used.

  However, depending on the compounding composition of the rubber, the conventional release film or the like may decrease the peelability after the crosslinking treatment, and the solution of the problem is strongly desired. For example, in recent years, a composite film in which a rubber sheet and a polymer film are combined has been developed for the purpose of improving the handleability of the rubber sheet and has been used in a wide range of fields. For example, Patent Documents 1 to 7 disclose a rubber sheet composite in which various films such as a polyester film and a rubber sheet are directly bonded without using an adhesive and a manufacturing method thereof.

  In the rubber sheet composites described in these patent documents, an adhesion improver is blended in the rubber sheet layer in order to improve adhesion with a film as a base material. However, when the rubber sheet layer is subjected to crosslinking treatment after laminating the above-described release film or the like due to the blending of the adhesive property improving agent, there arises a problem that the releasability of the release film becomes more remarkable.

  Note that some of the above-mentioned patent documents disclose various measures for solving such problems. For example, Patent Document 1 discloses a method of using a film made of poly-4-methylpentene or an ethylene / methyl methacrylate copolymer as a cover sheet. Although this method is effective as a method for improving the peelability, the film is less clean than the polyester film. For example, when used in the production of an optical rubber film composite, it adheres to the film surface. Or it has the problem that it is easy to form the defect part by the surface depression on the rubber film surface by the foreign material contained inside a film, and causes an optical defect.

Moreover, in patent document 2, the rubber film layer is multilayered, and the compounding amount of the adhesion improver is changed between a layer in contact with a base film that requires strong adhesion and a layer in contact with a cover sheet that requires releasability. Patent Document 5 discloses a method for optimizing the electron beam irradiation method used for the crosslinking treatment. Moreover, the film which apply | coated hydrocarbon wax to the polyester film is disclosed as a release film for urethane foam manufacture (refer patent document 8).
JP 10-53659 A Japanese Patent Laid-Open No. 10-58605 JP-A-10-86282 Japanese Patent Laid-Open No. 10-95071 Japanese Patent Laid-Open No. 10-119394 Japanese Patent Laid-Open No. 10-226022 Japanese Patent Laid-Open No. 11-157010 JP 2004-209756 A

  However, the methods described in Patent Documents 1 to 7 are disadvantageous economically because the manufacturing method is complicated and it is difficult to balance adhesiveness and peelability unless strict management is performed. There was a case. In addition, when the film described in Patent Document 8 is used as the rubber release film, a large peeling force is required due to the crosslinking treatment (increase in adhesion), which is inappropriate as a rubber release film. From such a background, it has been strongly desired to provide a release film for rubber having a balance between peelability and adhesion.

  Therefore, the present invention hardly increases the peeling force even when the rubber is crosslinked on the rubber surface of a rubber molded body such as a rubber sheet or a rubber laminate, and has low peeling even after the crosslinking treatment. It is an object to provide a release film for rubber that can be peeled off from a rubber sheet by force.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
The release film for rubber of the present invention that has solved the above problems is a release polyester film for rubber that is used for protecting a rubber layer, on at least one side of a polyester base film, a resin binder (A), a high It is characterized by having a release layer containing a molecular wax component (B) and an antistatic agent (C).

  Further, the release polyester film for rubber of the present invention is obtained by laminating the release polyester film for rubber so that the release layer surface is in contact with the surface of the uncrosslinked or semicrosslinked rubber. The peel strength between the rubber layer after crosslinking and the release layer is preferably 0.03 to 1.0 N / 20 mm.

  The release polyester film for rubber according to the present invention is hardly affected by the cross-linking adhesive force, which is a characteristic of rubber, even when the rubber is subjected to a cross-linking treatment in a state where it is laminated on the surface of an uncross-linked or semi-cross-linked rubber. Also, an increase in peeling force is unlikely to occur. Therefore, it can be suitably used as a fabric film on a rubber surface, a release film for rubber (separate film), or the like.

  The release polyester film for rubber according to the present invention is a release polyester film for rubber used for protecting a rubber layer, and a resin binder (A) and a polymer wax component on at least one surface of a polyester base film. It is characterized by having a release layer containing (B) and an antistatic agent (C).

[Polyester base film]
The polyester base film according to the present invention can be arbitrarily used as long as it has polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate or the like as a main component (80% by mass or more), and is biaxially stretched. Desirably used. The production method of the biaxially stretched polyester film is not particularly limited. For example, after drying the polyester as necessary, it is supplied to a known melt extruder, extruded into a sheet form from a slit die, and electrostatically applied. It is sufficient that the unstretched sheet is stretched after being brought into close contact with the casting drum by a method such as the above, cooled and solidified to obtain an unstretched sheet. The biaxial stretching method may be either simultaneous biaxial stretching or sequential biaxial stretching.

  In the present invention, the surface roughness (properties) of the polyester base film is not limited. However, the surface roughness of a layer (for example, a rubber layer described later) in contact with the release layer can be controlled by controlling the surface roughness of the surface on which the release layer described later is laminated. Therefore, controlling the surface roughness of the polyester base film is one of the preferred embodiments of the present invention. The method for controlling the surface roughness of the polyester-based substrate film is not particularly limited, but for example, a polyester-based substrate film whose surface is patterned by embossing or the like is preferably exemplified. By using a film having a pattern on the surface in this way as a substrate film, the pattern can be easily transferred to the surface of the layer in contact with the substrate film (for example, a rubber layer). In addition, a surface roughening substance or the like may be directly added to the release layer described later to control the surface properties of the layer in contact with the release layer.

(Release layer)
The release polyester film for rubber according to the present invention comprises a release layer containing a resin binder (A), a polymer wax component (B) and an antistatic agent (C) on at least one side of the polyester base film. Have

  The release layer in the release polyester film for rubber of the present invention is such that when the rubber layer is provided on the release layer, the peel strength between the rubber layer and the release layer satisfies the range described below. preferable.

  The resin binder (A) is preferably at least one polymer selected from the group consisting of polyester, polyurethane and acrylic polymer, and these polymers may be used alone or differently. Two or three kinds may be used in combination. The resin-based binder (A) contained in the release layer has a low necessity for crosslinking, but may be crosslinked by using a crosslinking agent in combination with the above polymer, or a self-crosslinking type polymer may be used.

[Polyester for resin binder (A)]
The polyester has an ester bond in the main chain or side chain, and is obtained by polycondensation of polyvalent carboxylic acid and glycol.

  As the polyvalent carboxylic acid component constituting the polyester, aromatic, aliphatic, and alicyclic dicarboxylic acids, trivalent or higher polyvalent carboxylic acids, and ester derivatives thereof can be used.

  Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxy Ethane-p, p′-dicarboxylic acid, phenylindanedicarboxylic acid and the like can be used. From the viewpoint of the strength and heat resistance of the release layer, these aromatic dicarboxylic acids are preferably 30 mol% or more, more preferably 35 mol% or more, more preferably 40 mol% in 100 mol% of the polyvalent carboxylic acid component. It is preferable to use polyester that accounts for the above.

  Examples of the aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like, and ester-forming derivatives thereof can be used.

  Examples of the glycol component of polyester include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol Neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2, 4-trimethyl-1,6-hexanediol, 1,2-cyclo Xanthodimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2-norbornylidene) diphenol, 4,4′-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene, 4,4′-isopropylidene bin Diol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol and the like can be used.

  In addition, when using polyester as an aqueous liquid as a coating liquid, a compound containing a carboxylic acid (salt) group or a compound containing a sulfonic acid (salt) group is used to facilitate water-solubilization or water-dispersion of the polyester. It is preferable to copolymerize a compound containing a phosphonic acid (salt) group.

  Examples of the compound containing a carboxylic acid (salt) group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, 1 , 2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 5- (2,5-dioxotetrahydro Furfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimellite 2,2 ′, 3,3′-diphenyltetracarboxylic acid, thiophene-2,3,4,5-tetracarboxylic acid, ethylenetetracarboxylic acid, etc., or alkali metal salts, alkaline earth metal salts thereof, An ammonium salt etc. can be mentioned.

  Examples of the compound containing a sulfonic acid (salt) group include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, sulfo-p-xylylene glycol, 2-sulfo-1,4-bis (hydroxyethoxy) benzene or the like, or an alkali metal salt, alkaline earth metal salt, or ammonium salt thereof can be used.

  Examples of the compound containing a phosphonic acid (salt) group include phosphoterephthalic acid, 5-phosphoisophthalic acid, 4-phosphoisophthalic acid, 4-phosphonaphthalene-2,7-dicarboxylic acid, phospho-p-xylylene glycol, 2-phospho-1,4-bis (hydroxyethoxy) benzene or the like, or an alkali metal salt, alkaline earth metal salt, or ammonium salt thereof can be used.

  In the present invention, for example, a modified polyester copolymer such as a block copolymer or a graft copolymer modified with acrylic, urethane, epoxy, or the like can be used as the polyester.

  Preferred polyesters include those selected from terephthalic acid, isophthalic acid, sebacic acid, 5-sodium sulfoisophthalic acid as the acid component, and ethylene glycol, diethylene glycol, 1,4-butanediol, and neopentyl glycol as the glycol component. And the like. When water resistance is required, a copolymer or the like containing trimellitic acid as its copolymer component can be suitably used instead of 5-sodium sulfoisophthalic acid.

  The polyester can be produced by the following production method. For example, a polyester comprising terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid as a dicarboxylic acid component, and ethylene glycol or neopentyl glycol as a glycol component will be described. The dicarboxylic acid component and the glycol component are directly esterified. Or it can manufacture by the method etc. which manufacture by the 1st step which transesterifies, and the 2nd step which carries out the polycondensation reaction of the reaction product of this 1st step.

  At this time, for example, alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound, or the like can be used as the reaction catalyst.

  Further, as a method for obtaining a polyester having many carboxyl groups at the terminal and / or side chain, JP-A-54-46294, JP-A-60-209073, JP-A-62-240318, JP JP 53-26828, JP 53-26829, JP 53-98336, JP 56-116718, JP 61-124684, JP 62-240318 Although it can be produced by copolymerizing a trivalent or higher polyvalent carboxylic acid described in the gazette, etc., other methods may be used.

  As the water-dispersed polyester resin, for example, a commercially available “Vaironal (registered trademark)” series (manufactured by Toyobo Co., Ltd.) can also be used.

  The intrinsic viscosity of the polyester is not particularly limited, but is preferably 0.3 dl / g or more, more preferably 0.35 dl / g or more, most preferably in terms of adhesion between the release layer and the polyester base film. Preferably it is 0.4 dl / g or more. The glass transition temperature (hereinafter sometimes abbreviated as Tg) of the polyester is preferably 0 to 130 ° C, more preferably 10 to 85 ° C. By using a polyester having a Tg of 0 ° C. or higher, the adhesion between the release layer and the polyester base film is improved at a high temperature, and after the release layer is laminated on the surface of the polyester base film, Blocking phenomenon such as winding can be suppressed. Moreover, stability and water dispersibility can be favorably maintained by using polyester with Tg of 130 ° C. or lower.

[Polyurethane for resin binder (A)]
Next, polyurethane will be described. The polyurethane is not particularly limited as long as it has a urethane bond, and the main component is obtained by polymerizing a polyol compound and a polyisocyanate compound.

  Examples of the polyol compound include polyethylene glycol, polypropylene glycol, polyethylene / propylene glycol, polytetramethylene glycol, hexamethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, triethylene glycol, polycaprolactone. Polyhexamethylene adipate, polytetramethylene adipate, trimethylolpropane, trimethylolethane, glycerin, acrylic polyol and the like can be used.

  Examples of the polyisocyanate compound include tolylene diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, an adduct of tolylene diisocyanate and trimethylolpropane, an adduct of hexamethylene diisocyanate and trimethylolethane, and the like. it can.

  In the synthesis of the polyurethane, a known chain extender, a crosslinking agent, and the like may be included in addition to the polyol compound and the polyisocyanate compound. As the chain extender or crosslinking agent, ethylene glycol, propylene glycol, butanediol, diethylene glycol, ethylenediamine, diethylenetriamine, or the like can be used.

  In order to obtain a stable polyurethane water dispersion, it is preferable to synthesize polyurethane having an increased affinity for water. Specifically, an appropriate amount of anionic groups may be introduced into the polyurethane. For example, a method of using a compound having an anionic group for polyol, polyisocyanate, chain extender, etc., a method of reacting an unreacted isocyanate group of the produced polyurethane with a compound having an anionic group, or having an active hydrogen of polyurethane It can be produced by a method of reacting a group with a specific compound.

  The anionic group in the polyurethane is preferably used as a sulfonic acid group, a carboxylic acid group, and an ammonium salt, lithium salt, sodium salt, potassium salt or magnesium salt thereof.

  The amount of the unit having an anionic group in the polyurethane is preferably 0.05% by mass to 15% by mass from the viewpoint of water dispersibility of the polyurethane. If it is less than 0.05% by mass, the water dispersibility of the polyurethane tends to be poor, and if it exceeds 8% by mass, the water resistance and blocking resistance tend to be inferior.

  For example, as a polyurethane water dispersion, “Hydran (registered trademark)” series (manufactured by Dainippon Ink & Chemicals, Inc.) can be used.

[Acrylic polymer for resin binder (A)]
Examples of the monomer component constituting the acrylic polymer include, for example, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and t-butyl groups. Hydroxy group-containing monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate), 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.) ; (Meth) acrylamide N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-phenyl (meth) acrylamide, etc. Amino group-containing monomer such as N, N-diethylaminoethyl (meth) acrylate; epoxy group-containing monomer such as glycidyl (meth) acrylate; (meth) acrylic acid and salts thereof (lithium salt, sodium salt, A monomer containing a carboxyl group such as potassium salt or the like or a salt thereof can be used, and these are (co) polymerized using one kind or two or more kinds. Furthermore, these can be used in combination with other types of monomers.

  Examples of other types of monomers include epoxy group-containing monomers such as allyl glycidyl ether; sulfonic acids such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) Monomer containing a group and a salt thereof; a monomer containing a carboxyl group or a salt thereof such as crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) Monomers containing acid anhydrides such as maleic anhydride and itaconic anhydride; vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid mono ester Le, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, may be used vinyl chloride.

  Moreover, as said acrylic polymer, a modified acrylic polymer, for example, a block copolymer modified with polyester, polyurethane, epoxy resin, etc., a graft copolymer, etc. can be used.

  The lower limit of Tg of the acrylic polymer is preferably −10 ° C. from the viewpoint of blocking resistance, more preferably 0 ° C., and most preferably 10 ° C. On the other hand, the Tg of the acrylic polymer is preferably 90 ° C., more preferably 50 ° C., and most preferably 40 ° C. in terms of adhesion between the release layer and the polyester base film and film forming properties. It is. Further, the weight average molecular weight (Mw) of the acrylic polymer is preferably 50,000 or more, more preferably 300,000 or more from the viewpoint of adhesion.

  Preferable examples of the acrylic polymer include copolymers composed of monomers selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide, and acrylic acid.

  It is preferable to dissolve, emulsify, or suspend an acrylic polymer in water and use it as an aqueous liquid in terms of reducing environmental pollution and explosion-proof properties during coating. Such water-based acrylic polymers are copolymerized with monomers having a hydrophilic group (acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid and salts thereof, etc.) and emulsion polymerization using reactive emulsifiers and surfactants, It can be produced by a method such as suspension polymerization or soap-free polymerization.

  Commercially available acrylic emulsions may also be used, for example, “Jonkrill (registered trademark)” series (manufactured by BASF Japan).

[Crosslinking agent used for resin binder (A)]
In the present invention, the polyester, polyurethane and acrylic polymer may be crosslinked. When the above polymer is cross-linked using a cross-linking agent, as the cross-linking agent, a functional group present in the above-described polymer, such as a carboxyl group, a hydroxyl group, a methylol group, an amide group, or the like can be used. Good. For example, melamine crosslinking agent, oxazoline crosslinking agent, isocyanate crosslinking agent, aziridine crosslinking agent, epoxy crosslinking agent, methylolated or alkylolized urea, acrylamide, polyamide resin, amide epoxy compound, various silanes A coupling agent, various titanate coupling agents, etc. can be used. In particular, a melamine-based crosslinking agent and an oxazoline-based crosslinking agent are preferably used from the viewpoints of compatibility with the polymer and adhesion to a polyester-based substrate film.

  The melamine-based crosslinking agent is not particularly limited, but is a melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, a compound partially or completely etherified by reacting a methylolated melamine with a lower alcohol, or these Or the like. In addition, as the melamine-based crosslinking agent, a monomer, a condensate composed of a dimer or higher polymer, a mixture thereof, or the like is used. As the lower alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are used. Methylolated melamine resins such as methylated trimethylolmelamine and butylated hexamethylolmelamine are preferred. Furthermore, in order to accelerate | stimulate the thermosetting of a melamine type crosslinking agent, you may use acidic catalysts, such as p-toluenesulfonic acid.

  Further, the oxazoline-based crosslinking agent is not particularly limited as long as it has an oxazoline group as a functional group in the compound, but includes at least one monomer containing an oxazoline group, and at least one kind of What consists of an oxazoline group containing copolymer obtained by copolymerizing another monomer is preferable.

  Monomers containing an oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be used, and one or a mixture of two or more thereof can also be used. Of these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially.

  In the oxazoline group-containing copolymer, the at least one other monomer used together with the oxazoline group-containing monomer is not particularly limited as long as it is a monomer copolymerizable with the oxazoline group-containing monomer. (Meth) acrylates such as (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid; Unsaturated nitriles such as (meth) acrylonitrile; Unsaturated amides such as (meth) acrylamide and N-methylol (meth) acrylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether Ters; Olefins such as ethylene and propylene; Halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α, β-unsaturated aromatics such as styrene and α-methylstyrene Monomers etc. can be used and these can use 1 type, or 2 or more types of mixtures.

  As the oxazoline group-containing polymer, for example, “Epocross (registered trademark)” series (manufactured by Nippon Shokubai Co., Ltd.) is available.

  The isocyanate-based crosslinking agent is not particularly limited as long as it has an isocyanate group as a functional group in the compound, but it is preferable to use a polyfunctional isocyanate compound containing two or more isocyanate groups in one molecule.

  As the polyfunctional isocyanate compound, a low-molecular or high-molecular aromatic or aliphatic diisocyanate or a trivalent or higher polyisocyanate can be used. Examples of the polyisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds. Furthermore, an excess amount of these isocyanate compounds and low molecular active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or polyester polyols, poly The terminal isocyanate group containing compound obtained by making it react with polymer active hydrogen compounds, such as ether polyols and polyamides, can be mentioned.

  In addition, when using an isocyanate compound as a crosslinking agent, it is also possible to use a block type isocyanate compound. The blocked isocyanate can be prepared by subjecting the above isocyanate compound and blocking agent to an addition reaction by a conventionally known appropriate method. Examples of the isocyanate blocking agent include phenols such as phenol, cresol, xylenol, resorcinol, nitrophenol and chlorophenol; thiophenols such as thiophenol and methylthiophenol; oximes such as acetoxime, methyl etiketooxime and cyclohexanone oxime. Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; tertiary alcohols such as t-butanol and t-pentanol ; Lactams such as ε-caprolactam, δ-valerolactam, ν-butyrolactam, β-propyllactam; aromatic amines; imides; acetylacetone, acetoacetate, ethyl malonate Active methylene compounds such as esters, mercaptans, imines; ureas; diaryl compounds; sodium bisulfite, and the like.

  The epoxy-based crosslinking agent is not particularly limited as long as it has an epoxy group as a functional group in the compound. However, it is preferable to use a polyfunctional epoxy compound having two or more epoxy groups in one molecule. .

  Examples of the polyfunctional epoxy compound include diglycidyl ether of bisphenol A and oligomer thereof, diglycidyl ether of hydrogenated bisphenol A and oligomer thereof, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-oxybenzoic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, ethylene glycol diglycidyl ether, propylene Glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and Polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl Examples include ether, triglycidyl ether of glycerol alkylene oxide adduct, and the like.

  As the cross-linking agent, a phenol formaldehyde resin of a condensate with formaldehyde such as alkylated phenols and cresols; an adduct of urea, melamine, benzoguanamine and the like with formaldehyde, this adduct and an alcohol having 1 to 6 carbon atoms An amino resin such as an alkyl ether compound consisting of can also be used.

  Examples of the phenol formaldehyde resin include alkylated (methyl, ethyl, propyl, isopropyl or butyl) phenol, p-tert-amylphenol, 4,4′-sec-butylidenephenol, p-tert-butylphenol, o-, m-, p-cresol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl-o-cresol, p-phenylphenol, xylenol, etc. And the condensates of phenols and formaldehyde.

  Examples of amino resins include methoxylated methylol urea, methoxylated methylol N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine, and the like. However, preferably, methoxylated methylol melamine, butoxylated methylol melamine, methylolated benzoguanamine and the like can be mentioned.

  The polymer (polyester, polyurethane, acrylic polymer) and the crosslinking agent can be mixed and used at an arbitrary ratio, but the crosslinking agent is 2 parts by mass or more and 50 parts by mass in solid content with respect to 100 parts by mass of the polymer. Addition of less than or equal to parts by weight is preferred, more preferably 3 to 25 parts by weight. When the addition amount of the crosslinking agent is out of the above range, the adhesion between the release layer and the polyester base film tends to be lowered.

[Self-crosslinking polymer for resin binder (A)]
In the present invention, in addition to the above method, for example, a self-crosslinking polymer in which a crosslinkable functional group is introduced into the above-described polymer may be used as the resin binder (A). In the case of using a self-crosslinking type polymer, the crosslinking method may be, for example, thermal crosslinking, or may be crosslinking with high energy active rays such as ultraviolet rays, electron beams and γ rays.

  Hereinafter, a specific method will be illustrated for the case of polyester as the self-crosslinking polymer.

  The self-crosslinking type polyester preferably used in the present invention is a polyester graft copolymer obtained by grafting a hydrophobic copolymer polyester with a compound having at least one radical polymerizable double bond. The “grafting” of the polyester-based graft copolymer in the present invention is to introduce a branched polymer made of a polymer different from the main chain into the backbone polymer which is the main chain. Graft polymerization is usually carried out by reacting at least one radically polymerizable monomer using a radical initiator in a state where a hydrophobic copolyester is dissolved in an organic solvent. Hydrophobic copolyesters are essentially water-insoluble polyesters that do not inherently dissolve in water, so water resistance is higher than when polyester resins that are soluble in water are used as the backbone polymer for graft polymerization. Excellent in adhesion and adhesiveness.

  The hydrophobic copolyester is composed of 60 to 99.5 mol% of aromatic dicarboxylic acid, 0 to 39.5 mol% of aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid in 100 mol% of dicarboxylic acid component, radical It is preferable that the dicarboxylic acid containing a polymerizable double bond is 0.5 to 10 mol%. More preferably, the aromatic dicarboxylic acid is 68 to 98 mol%, the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid is 0 to 30 mol%, and the dicarboxylic acid containing a polymerizable unsaturated double bond is 2 to 7 Mol%.

  When the aromatic dicarboxylic acid is 60 mol% or more and the aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid is 39.5 mol% or less, the adhesion is good. Moreover, the grafting of the radically polymerizable monomer with respect to the polyester resin can be efficiently performed by using 0.5 mol% or more of the dicarboxylic acid containing a radically polymerizable double bond. On the other hand, the content of 10 mol% or less is preferable because the viscosity of the reaction solution can be prevented from significantly increasing in the later stage of the grafting reaction, and the reaction can proceed uniformly.

  As the aromatic dicarboxylic acid, aliphatic and / or alicyclic dicarboxylic acid, any of the compounds exemplified above can be used. Examples of the dicarboxylic acid containing a radical polymerizable double bond include fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid and other α, β-unsaturated dicarboxylic acids; 2,5-norbornene dicarboxylic acid anhydride, Examples thereof include alicyclic dicarboxylic acids containing unsaturated double bonds such as tetrahydrophthalic anhydride. Of these dicarboxylic acids containing a polymerizable unsaturated double bond, fumaric acid, maleic acid, and 2,5-norbornene dicarboxylic acid are preferred from the viewpoint of polymerizability.

  As the glycol component, any of the compounds exemplified above can be used. Two or more glycol components may be used in combination. Especially, C2-C10 aliphatic glycol, C6-C12 alicyclic glycol, ether group containing glycol, etc. are preferable.

  Examples of the ether group-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, such as 2,2-bis. (4-hydroxyethoxyphenyl) propane and the like can be mentioned. Polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can also be used if necessary.

  The hydrophobic copolymerized polyester may be copolymerized with 0 to 5 mol% of a trifunctional or higher polycarboxylic acid and / or polyol. The tri- or higher functional polycarboxylic acid includes (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenone tetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (an Hydrotrimellitate) and the like. As the trifunctional or higher functional polyol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, or the like is used.

  The tri- or higher functional polycarboxylic acid and / or polyol is copolymerized in the range of 0 to 5 mol%, preferably 0 to 3 mol%, based on the total acid component or the total glycol component. Gelation can be suppressed.

  The lower limit of the weight average molecular weight of the hydrophobic copolyester is preferably 5,000 from the viewpoint of adhesion. Moreover, it is preferable that an upper limit is 50,000 at points, such as gelatinization at the time of superposition | polymerization.

  After synthesizing the hydrophobic copolyester, graft polymerization is performed. Graft polymerization is performed by reacting at least one radical polymerizable monomer using a radical initiator in a state where the hydrophobic copolyester is dissolved in an organic solvent. The reaction product after completion of the grafting reaction is not limited to the graft copolymer of the desired hydrophobic copolymerized polyester and the radically polymerizable monomer, but also the hydrophobic copolymerized polyester and the hydrophobic copolymer that were not subjected to grafting. It also contains a (co) polymer obtained from a radically polymerizable monomer that has not been grafted to the polyester. The polyester-based graft copolymer in the present invention includes not only the above-described polyester-based graft copolymer, but also a hydrophobic copolymerized polyester that has not been grafted, and a radically polymerizable monomer that has not been grafted. Also included are reaction mixtures containing the resulting (co) polymer and monomer (residual monomer).

  The mass ratio of the desired hydrophobic copolymerized polyester and the radical polymerizable monomer suitable for the purpose of the present invention is preferably in the range of polyester / radical polymerizable monomer = 40/60 to 95/5, more preferably 55/45. ~ 93/7, most desirably in the range of 60/40 to 90/10.

  By setting the mass ratio of the hydrophobic copolymerized polyester to 40% by mass or more, excellent adhesion of the polyester can be exhibited. On the other hand, blocking resistance can be improved by making the mass ratio of hydrophobic copolyester 95 mass% or less.

  The graft polymerization reaction product is in the form of an organic solvent solution or dispersion or an aqueous solvent solution or dispersion. In particular, a dispersion of an aqueous solvent, that is, a form of an aqueous dispersion is preferable in terms of working environment and applicability. Therefore, as the radical polymerizable monomer to be grafted, it is preferable to use a radical polymerizable monomer that essentially contains a hydrophilic radical polymerizable monomer. Then, after graft polymerization in an organic solvent, an aqueous dispersion can be obtained by adding water and distilling off the organic solvent.

  The hydrophilic radical polymerizable monomer means a radical polymerizable monomer having a hydrophilic group or a group that can be changed to a hydrophilic group later. Examples of the radical polymerizable monomer having a hydrophilic group include a radical polymerizable monomer containing a carboxyl group, hydroxyl group, phosphoric acid group, phosphorous acid group, sulfonic acid group, amide group, quaternary ammonium base and the like. . On the other hand, examples of the radical polymerizable monomer having a group that can be changed into a hydrophilic group include radical polymerizable monomers containing an acid anhydride group, a glycidyl group, a chloro group, and the like. Among these, from the viewpoint of water dispersibility, a carboxyl group is preferable, and a radical polymerizable monomer having a carboxyl group or a group capable of generating a carboxyl group is preferable.

  Examples of the graft polymerization initiator used in the present invention include organic peroxides and organic azo compounds known to those skilled in the art. Examples of the organic peroxide include benzoyl peroxide, t-butyl peroxypivalate, and examples of the organic azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2, 4-dimethylvaleronitrile). The amount of the polymerization initiator used for the graft polymerization is at least 0.2% by mass, preferably 0.5% by mass or more, based on the radical polymerizable monomer.

  In addition to the polymerization initiator, a chain transfer agent for adjusting the chain length of the branched polymer, for example, octyl mercaptan, mercaptoethanol, 3-t-butyl-4-hydroxyanisole may be used as necessary. In this case, it is desirable to add in the range of 0 to 5% by mass with respect to the polymerizable monomer.

  The grafting reaction product is preferably neutralized with a basic compound, and can be easily dispersed in water by neutralization. As the basic compound, a compound that volatilizes at the time of coating film formation is desirable, and ammonia, organic amines, and the like are preferable. Desirable compounds include, for example, triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine , 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanol An amine etc. can be mentioned.

  The basic compound has a pH value of the aqueous dispersion in the range of 5.0 to 9.0 by at least partial neutralization or complete neutralization, depending on the carboxyl group content contained in the grafting reaction product. It is desirable to use it. If a basic compound having a boiling point of 100 ° C. or lower is used, the amount of the basic compound remaining in the coating film after drying is small, and, for example, adhesion under a severe environment such as high temperature and high humidity is improved.

  In the grafting reaction product, the weight average molecular weight of the polymer of the radical polymerizable monomer is preferably 500 to 50,000. It is generally difficult to control the weight average molecular weight of the polymer of the radical polymerizable monomer to be less than 500, the graft efficiency is lowered, and there is a tendency that hydrophilic groups are not sufficiently imparted to the copolymer polyester. In addition, the graft polymer of the radical polymerizable monomer forms a hydrated layer of dispersed particles. To obtain a stable aqueous dispersion with a sufficient thickness of the hydrated layer, the graft polymer of the radical polymerizable monomer is used. The weight average molecular weight of is desirably 500 or more.

  The upper limit of the weight average molecular weight of the graft polymer of the radical polymerizable monomer is preferably 50,000 from the viewpoint of polymerizability in solution polymerization. In order to make the weight average molecular weight of the graft polymer of the radical polymerizable monomer within the range of 500 to 50,000, the initiator amount, the monomer dropping time, the polymerization time, the reaction solvent, the monomer composition, or the chain as necessary. It is preferable to carry out by appropriately combining a transfer agent and a polymerization inhibitor.

  In the present invention, a reaction product obtained by graft polymerization of a radically polymerizable monomer to a hydrophobic copolymerized polyester has a self-crosslinking property because a hydroxyl group in the polyester and a carboxyl group present in the graft portion react. Moreover, although it does not bridge | crosslink at normal temperature, it carries out intermolecular reaction, such as a hydrogen abstraction reaction by a thermal radical, with the heat at the time of drying at the time of coating-film formation, and bridge | crosslinks without a crosslinking agent. Thereby, adhesiveness with a polyester-type base film increases, and the transfer to the rubber | gum surface of a release layer is suppressed. Moreover, blocking is also suppressed. The degree of crosslinking of the coating film can be evaluated by various methods, and examples thereof include a method of measuring the insoluble fraction in a chloroform solvent or the like that dissolves both the hydrophobic copolymerized polyester and the grafted polymer.

  The insoluble fraction of the coating film obtained by drying at about 80 ° C. and heat-treating at 120 ° C. for 5 minutes is preferably 50% by mass or more, more preferably 70% by mass from the viewpoints of hot water adhesion and blocking resistance. That's it.

  As the self-crosslinking polyester resin aqueous dispersion, for example, a commercially available product such as “Vylonal (registered trademark) AGN702” (manufactured by Toyobo Co., Ltd.) can be used.

  In addition, a grafted polyurethane can be prepared by a method similar to the above.

[Polymer wax component (B)]
As the polymer wax component (B) used in the present invention, conventionally known materials can be used. For example, wax emulsions such as polyethylene, polypropylene, acrylic, and fatty acid are shown, but a polymer wax agent that is particularly hard and does not have a sticky feeling and has excellent thermal decomposition stability is effective in improving peelability. Further, it is preferable because the transfer of wax to the opposite surface can be suppressed during film winding. Moreover, the number average molecular weight of these wax agents is preferably 1,000 to 10,000, more preferably 1,500 to 6,000.

  The polymer wax component (B) is preferably contained in an amount of 2 to 10% by mass in terms of solid content when the total amount with the resin binder (A) is 100% by mass. More preferably 3 to 8% by mass is contained. By making the addition amount of the polymer wax component (B) 2% by mass or more, it is possible to improve the peelability from the rubber layer after the crosslinking treatment and to improve the slipping property of the polyester base film. it can. On the other hand, when the addition amount of the polymer wax component is 10% by mass or less, the peeling force can be maintained. Further, since the migration of the polymer wax component (B) from the release layer can be suppressed, the surface of the rubber layer (described later) after the crosslinking treatment is less contaminated.

[Antistatic agent (C)]
As the antistatic agent (C) used in the release layer, the ionicity is not particularly limited as long as it can be mixed with the resin binder (A) or has compatibility. Conventionally known commercially available materials can be used. For example, anionic, cationic, nonionic, amphoteric surfactants, polymer surfactants, and the like can be used. Preferably, a polymer type antistatic agent with little bleed out to the laminated surface is preferred.

  As the polymer type antistatic agent, any of anionic type, cationic type and nonionic type can be used, and among them, anionic type and nonionic type polymeric antistatic agents are suitable.

  As the anionic polymer antistatic agent, for example, a polar polymer having at least one polar group selected from a sulfonic acid group, a carboxyl group, and a sulfate ester group or a salt thereof is preferable. The polar group needs 5 mol% or more per polymer molecule. These polar polymers having electrical conductivity may contain hydroxyl groups, amino groups, epoxy groups, aziridine groups, active methylene groups, sulfinic acid groups, aldehyde groups, and vinyl sulfone groups as polar groups. Among these, an antistatic agent containing styrene sulfonic acid or a salt thereof as a repeating unit is preferable.

  Examples of such an antistatic agent include polystyrene sulfonic acid or a salt thereof. Examples of the salt include ammonium salt, lithium salt, and sodium salt. Polystyrene sulfonic acid or a salt thereof is, for example, commercially available from Nippon SC under the trade name VERSA-TL (registered trademark) and various types of unneutralized salts having different molecular weights. Further, as an antistatic agent containing styrene sulfonic acid or a salt thereof as a repeating unit, a styrene sulfonic acid-maleic acid copolymer can also be used and is commercially available from Nippon SC.

  On the other hand, nonionic high molecular surfactants include aniline or derivatives thereof, pyrrole or derivatives thereof, isothianaphthene or derivatives thereof, acetylene or derivatives thereof, thiophene or derivatives thereof, and the like. Is preferred. Among them, a π-electron conjugated conductive polymer containing thiophene or a derivative thereof as a structural unit is preferable because it is less colored. The π-electron conjugated conductive polymer may be a homopolymer containing only one type of structural unit as a repeating unit or a copolymer containing two or more types of structural units as a repeating unit.

  Examples of the conductive polymer containing thiophene or a derivative thereof as a constitutional unit include, for example, “BYTRON (registered trademark) P” series manufactured by Starck Vitech, and “Denatron (registered trademark) P-502RG” manufactured by Nagase ChemteX. "Denatron (registered trademark) P-502S", Conisole F202, F205, F210, P810 (above, trade name) manufactured by Inscontec, CPS-AS-X03 (trade name) manufactured by Shin-Etsu Polymer, etc. are commercially available. .

  The blending amount of the antistatic agent (C) in the release layer cannot be uniquely determined because the preferred range differs depending on the type of the resin binder (A) and the type of the antistatic agent (C). What is necessary is just to adjust so that the peeling strength from the rubber layer of a type | mold layer may become said range.

  For example, when an anionic surfactant is used as the antistatic agent, the blending amount of the antistatic agent is the sum of the release binder and the resin binder so that the peel strength from the rubber layer is within the above range. Is 100% by mass, the solid content is preferably 2 to 10% by mass, more preferably 3 to 8% by mass. By making the compounding amount of the anionic surfactant 2% by mass or more, the peelability from the rubber layer after the crosslinking treatment is improved, and the antistatic property of the polyester base film is also improved. On the other hand, by setting the blending amount of the antistatic agent (C) to 10% by mass or less, it is possible to maintain the peeling force and suppress the occurrence of the channeling phenomenon in the production process of the release sheet for rubber. Furthermore, since the migration of the polymer wax component (B) from the release layer can be suppressed, the surface of the rubber layer after the crosslinking treatment is rarely contaminated.

[Formation method of release layer]
In order to form a release layer having the above structure on a polyester base film, a resin binder (A), a polymer wax component (B), an antistatic agent (C), and a surface roughened surface if necessary. A predetermined amount of another additive such as a chemical substance may be mixed in advance to prepare a resin composition, which may be applied. The resin composition may contain a surfactant for improving coatability, an ultraviolet ray inhibitor, an antioxidant, and the like. The coating method may be applied using a normal coating apparatus such as a gravure coater, reverse roll coater, reverse kiss coater, air knife coater, bar coater, etc., and the method is not limited to these. In addition, when obtaining a polyester base film, a so-called inline coating method in which a resin composition is applied to one side of a polyester base film stretched in a uniaxial direction, and further stretched in a direction perpendicular to the previous uniaxial stretch, A so-called off-line coating method applied after biaxial stretching is exemplified.

  The thickness of the release layer is preferably 0.03 to 1 μm and more preferably 0.05 to 0.5 μm in a dry state in order to make the peeling force within an appropriate range. If it is less than 0.03 μm, the peelability is insufficient, which is not preferable. On the other hand, if it exceeds 1 μm, the effect of the present invention is saturated, which is disadvantageous economically.

  The laminate in which the release layer is formed on the surface of the polyester base film is suitably used as a release film for rubber (the release polyester film for rubber of the present invention).

[Rubber layer]
The rubber component forming the rubber layer is not limited. For example, natural rubber (NR), silicone rubber (Q), ethylene propylene diene rubber (EPDM), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), acrylic rubber Any rubber such as (ACM) or fluoro rubber (FKM) or a mixture thereof can be used. The rubber component may be appropriately selected and used depending on the required characteristics according to the purpose of use.

  You may mix | blend an adhesive improvement agent with the said rubber component. For example, the above-mentioned correspondence is effective when a composite body in which a rubber layer is composited by laminating one surface of a rubber layer with another layer. In addition, as said other layer, it is preferable to use the polyester film which gave the process which improves adhesiveness to at least one surface.

  As the adhesion improver that can be blended with the rubber component, it is preferable to use a compound containing a reactive group active against a radical reaction. Examples of such compounds include (meth) acrylic acid derivatives and allyl derivatives. Among them, derivatives having 2 or more, particularly 3 or more unsaturated bonds are preferable. These compounds are widely used as rubber co-crosslinking agents, and examples thereof include (meth) acrylic acid esters of polyhydric alcohols, allyl esters of polycarboxylic acids, triallyl isocyanurate, triallyl cyanurate, and the like.

  The (meth) acrylic acid ester of a polyhydric alcohol is an ester compound obtained by esterifying two or more alcoholic hydroxyl groups of a polyhydric alcohol having two or more alcoholic hydroxyl groups with (meth) acrylic acid. Glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate 2,2′-bis (4- (meth) acryloxydiethoxyphenyl) propane, glycerin di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) Acrylate, pentaerythri Ol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tetramethylolmethane di (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethyloltetra (meth) acrylate, dimer diol di (meth) acrylate, etc. In particular, compounds containing 3 or more acryloyl groups are preferred. In addition, although said compound illustrated each single ester compound of acrylic acid and methacrylic acid, the form of mixed ester of acrylic acid and methacrylic acid may be sufficient.

  Examples of the allyl ester of polyvalent carboxylic acid include phthalic acid diarylate, trimellitic acid diarylate, and pyromellitic acid tetraarylate.

  Any one kind of the adhesion improver compounded in the rubber component may be used alone, or two or more kinds may be used in combination. In addition, the adhesive improvement agent used for this invention is not limited to said exemplary compound.

  The compounding amount of the adhesive property improving agent is preferably 0.2 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of all rubber components. If the blending amount is less than 0.2 parts by mass, the adhesive strength with the base film tends to be insufficient. On the other hand, even if blending exceeds 20 parts by mass, the effect of improving the adhesive strength commensurate with the blending amount is obtained. It is hard to be done, but there is a tendency that the physical properties of the rubber are rather lowered.

  Moreover, in order to make the adhesion improvement effect by the above-mentioned adhesion improving agent more remarkable, a peroxide compound may be blended with the rubber layer.

  The peroxide compound may be either acyl-based or alkyl-based, such as benzoyl peroxide, monochlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2, 5-bis (t-butylperoxy) hexane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-bis-t-butylperoxy-3,3,5 -Trimethylcyclohexane, di-t-butyl peroxide and the like are exemplified.

  The compounding amount of the peroxide compound is preferably 0.05 to 10 parts by mass, particularly 1 to 8 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount is less than 0.05 parts by mass, it is difficult to see the contribution to the effect of improving the adhesiveness, and even if blending exceeding 10 parts by mass, the above-mentioned adhesiveness improving effect is saturated, rather, a rubber layer or a polyester type The physical properties of the base film may be reduced.

[Lamination of rubber layer]
The method for laminating the rubber layer on the release polyester film for rubber according to the present invention is not particularly limited. For example, an uncrosslinked or semi-crosslinked rubber layer is formed on the surface of the release polyester film for rubber and then crosslinked. Method, preparing a rubber sheet having a rubber layer formed on the surface of a base film different from the above-mentioned release polyester for rubber, and releasing the rubber sheet of the present invention so that the rubber layer of the rubber sheet is in contact with the release layer. Examples include a method of cross-linking the rubber layer after laminating the polyester film.

  As a method for laminating a rubber layer on the surface of a release polyester film for rubber or other base film, a conventionally known method may be arbitrarily selected. For example, a rubber is formed on the surface of a release layer of a release polyester film for rubber. A method in which a solution in which the composition is dissolved in an organic solvent is applied and dried to form a rubber layer; a solution in which the rubber composition is dissolved in an organic solvent is applied to a different base film surface and then dried. A method of forming a rubber sheet having a rubber layer and laminating the obtained rubber sheet and a rubber release polyester film; the rubber composition is extruded under high pressure on the release layer surface of the release polyester film for rubber A method of forming a rubber layer; or a rubber sheet having a rubber layer is formed by extruding a rubber composition under high pressure on the surface of a separate substrate film, and the rubber sheet and a polyester film for rubber release are formed. How laminating Lum; calendering method. Moreover, when using liquid rubber like liquid silicone rubber, it can apply without diluting with a solvent.

  The method for crosslinking the rubber layer in the above production method is not particularly limited, and may be, for example, thermal crosslinking or crosslinking with high-energy active rays such as electron beams or γ rays. In particular, the method using actinic radiation does not require the addition of additives for generating radicals such as peroxides. For this reason, contamination of the adherend due to the residue of these additives and a decrease in physical properties of the rubber layer are suppressed, and it is not necessary to consider the pot life after adding a catalyst for crosslinking, etc. There is a merit such that productivity is increased because the process is completed.

  Among the actinic rays, the electron beam cross-linking method is preferable because of the availability of an irradiation device (EB irradiation device). As an electron beam irradiation amount in an EB irradiation apparatus, the range of 5-50 Mrad is preferable. By setting the electron beam irradiation amount to 5 Mrad or more, the cross-linking reaction of the rubber layer can be promoted, and the adhesive residue on the adherend can be reduced and the repairability can be improved when re-peeling. On the other hand, by setting the electron beam irradiation amount to 50 Mrad or less, it is possible to suppress a decrease in adhesiveness due to excessive progress of the crosslinking reaction.

[Peel strength between release layer and rubber layer]
The release polyester film for rubber of the present invention is a rubber layer obtained by laminating the release polyester film for rubber on the surface of an uncrosslinked or semi-crosslinked rubber through the release layer surface, and then performing a crosslinking reaction of the rubber layer. The peel strength between the surface and the release layer is 0.03 to 1.0 N / 20 mm. When the peel strength is 0.03 N / 20 mm or more, the film exhibits good peelability, and when used as a rubber release film (separator film), the rubber release polyester film of the present invention, the rubber layer, In the manufacturing process of the laminate, when the laminate is wound, the separator film can be prevented from being lifted, and the quality of the laminate can be kept high. On the other hand, if it is 1.0 N / 20 mm or less, the peelability between the rubber layer and the polyester film for rubber release of the present invention is good. By providing the release layer having the above structure on the surface of the polyester-based substrate film, the peel strength can be controlled within the above range. The peel strength was measured as follows.

  First, for a laminate (rubber sheet composite) of a rubber release polyester film and a rubber layer having a length of about 200 mm and a width of 20 mm, the rubber release polyester film is slightly peeled from the rubber sheet composite, and the release layer and the rubber Each layer is exposed. Next, the release polyester film for rubber composed of the polyester base film and the release layer was held with one chuck, and the rubber layer was held with the other chuck. And T-type peeling strength was measured by the method as described in JIS K6854-3. The tensile tester used was a trade name “Autograph” (manufactured by Shimadzu Corporation), and a T-type peel test was performed under conditions of a distance between chucks of 50 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min. During peeling, the end of the film was lifted with a bar so that the T-shape was maintained. The maximum strength at the time of T-type peeling was defined as the peeling strength.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, but may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. These are all included in the technical scope of the present invention. The measurement / evaluation methods employed in the examples are as follows. In the examples, “parts” means “parts by mass”, and “%” means “% by mass” unless otherwise specified.

1. Peel strength First, in order to measure the peel strength at the interface between the release layer and the rubber for a laminate sample (about 200 mm in length and 20 mm in width) obtained by laminating a release polyester film for rubber and a rubber layer, the release layer The release polyester film for rubber was peeled off slightly at the interface between the release layer and the rubber layer to expose each of the release layer and the rubber layer. Next, the release polyester film for rubber composed of the polyester base film and the release layer was held with one chuck, and the rubber layer was held with the other chuck. And T-type peeling strength was measured by the method as described in JIS K6854-3. The tensile tester used was a trade name “Autograph” (manufactured by Shimadzu Corporation), and a T-type peel test was performed under conditions of a distance between chucks of 50 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min. During peeling, the end of the sample was lifted with a stick so that the T-shape was maintained. The maximum strength at the time of T-type peeling was defined as the peeling strength. When the release layer and the rubber layer did not peel off, it was not measured as being difficult to peel off. In this case, the release layer does not function as a release layer.

Example 1
[Preparation of resin composition for coating for forming release layer]
Water-dispersible copolyester resin ("Vironal (registered trademark) MD1200", manufactured by Toyobo Co., Ltd.) as the resin binder component (A), polyethylene emulsion wax agent (RIKEN Vitamin Co., Ltd.) as the polymer wax component (B) A company), an anionic antistatic agent (“TB702” (sodium dodecyl diphenyloxide disulfonate), manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) as an antistatic agent (C), and styrene having an average particle size of 2 μm as a surface roughening substance. -Benzoguanamine-based spherical organic particles ("Eposter (registered trademark) MS" manufactured by Nippon Shokubai Co., Ltd.) and inorganic colloidal particles having an average particle size of 0.05 [mu] m (trade name "Snowtex (registered trademark) XL" Nissan Chemical Industries Ltd. Each).

  The organic spherical particles of the surface roughening material are sufficiently dispersed in a mixed solution of water and isopropyl alcohol (mass ratio 80/20) using a homogenizer, and then the resin-based binder with respect to the total mass of the coating solution (A) 2.5% by mass, polymer wax component (B) 0.13% by mass, antistatic agent (C) 0.13% by mass, organic spherical particles 0.025% by mass and inorganic colloidal particles 0.3 The resin composition for coating for forming a release layer was prepared by sufficiently mixing so as to be in mass%.

[Manufacture of release polyester film for rubber]
The resin composition for application was applied onto a polyester base film (“E5100”, manufactured by Toyobo Co., Ltd., thickness of about 100 μm) using a wire bar (No. 5). The coating amount of the coating solution was about 8 to 10 g (wet state) per 1 m ^{2 of the} base film. The coating solution was dried at 160 ° C. for about 60 seconds to obtain a release polyester film for rubber.

[Manufacture of rubber sheet composite]
60:40 weight of commercially available high strength silicone rubber compound (“KE555-U”, manufactured by Shin-Etsu Chemical Co., Ltd.) and commercially available silicone rubber compound for general molding (“KE958-U”, manufactured by Shin-Etsu Chemical Co., Ltd.) The mixture blended at a ratio was kneaded at 100 ° C. using two rolls to form a rubber sheet having a thickness of 3 mm. This unvulcanized rubber sheet is cut into 1 cm square pieces, which are weighed so that the mass ratio with respect to toluene is 23%, and put into a stirrer with a vacuum deaerator together with toluene, Under stirring for 15 hours, the strips were dissolved in toluene. To the obtained solution, with respect to 100 parts by mass of the silicone rubber compound, trimethylolpropane trimethacrylate was added so as to be 2 parts, and after stirring uniformly, the vacuum deaerator was driven and the gauge pressure was- The mixture was further stirred for 20 minutes under a vacuum of 750 mmHg and defoamed. Next, the silicone rubber compound solution after defoaming is supplied to a roll coater, and easy adhesion of a 100 μm thick polyethylene terephthalate film (“Cosmo Shine (registered trademark) A4100”, manufactured by Toyobo Co., Ltd.) subjected to easy adhesion treatment. On the treated surface, the above silicone rubber compound solution was applied so that the thickness after drying was 25 μm, then introduced into an oven and dried at 80 ° C. to obtain a laminate having an uncrosslinked rubber layer.

Next, the rubber layer surface of the obtained laminate was continuously laminated while pressing the release polyester film for rubber (separator film) prepared by the above method with a pressure roller (pressure 30 N / cm ² ). The obtained laminate is continuously introduced into an electron beam irradiation apparatus, and the rubber layer is crosslinked by irradiating an electron beam with energy of 200 KV and 15 Mrad from the separator film side, and a rubber having a crosslinked rubber layer The sheet composite was wound into a roll.

  In the production of the rubber sheet composite, no occurrence of lifting of the release polyester film for rubber (separator film) was observed. Moreover, the peeling strength of the separator film (release polyester film for rubber) from the obtained rubber sheet composite after crosslinking is 0.2 N / 20 mm, and can be easily peeled from the rubber layer. The laminated polyester film obtained in 1 was high quality as a release film for rubber.

Comparative Example 1
In the method of Example 1, it was the same as Example 1 except that the polymer wax component (B) and the antistatic agent (C) were not blended during the preparation of the release layer-forming coating resin composition. Thus, a release film for rubber and a rubber sheet composite were obtained.

  An attempt was made to peel the release polyester film for rubber from the obtained rubber sheet composite, but the release polyester film for rubber could not be peeled. A cut was made at the interface between the rubber release polyester film and the rubber layer with a knife, but the interface could not be removed.

  The release polyester film for rubber obtained in this Comparative Example 1 was inferior in peelability, and the quality was low as a release film for rubber.

Comparative Examples 2 and 3
In Example 1, when preparing the resin composition for forming a release layer, the mixing of the antistatic agent (C) in Comparative Example 2 and the polymer wax component (B) in Comparative Example 3 was canceled. Except for the above, a release film for rubber and a rubber sheet composite were obtained in the same manner as in Example 1.

  An attempt was made to peel the release film for rubber from the obtained rubber sheet composite, but in Comparative Example 2, the separator film was heavy. Further, in the rubber sheet composite obtained in Comparative Example 3, the separator film could not be peeled like the rubber sheet composite obtained in Comparative Example 1. The peel strength of the separator film was 4 N / 20 mm in the case of the rubber sheet composite obtained in Comparative Example 2, and in the case of the rubber sheet composite obtained in Comparative Example 2, no interface was formed.

  The release polyester film for rubber obtained in these comparative examples was inferior in releasability, and the quality was low as a release film for rubber.

Comparative Example 4
A release film for rubber and a rubber sheet composite were produced in the same manner as in Example 1 except that a commercially available silicone-treated release polyester film (“E7002” manufactured by Toyobo Co., Ltd.) was used as the separator film. Got.

  An attempt was made to peel the separator film from the obtained rubber sheet composite, but the separator film could not be peeled off. Even if a cut was made at the interface between the separator film and the rubber layer with a knife, the interface could not be formed.

  The release polyester film for rubber obtained in this comparative example was inferior in peelability, and was low quality as a release film for rubber.

Example 2
A rubber sheet composite was obtained in the same manner as in Example 1 except that the polyester film for rubber release produced by the following method was used as a separator film.

  In the same manner as in Example 1, no occurrence of lifting of the release polyester film for rubber was observed during the production of the rubber sheet composite. Further, the peel strength of the release polyester film for rubber from the obtained rubber sheet composite was 0.1 N / 20 mm, and the release polyester film for rubber was the same as the rubber sheet composite obtained in Example 1. The release polyester film for rubber obtained in this example was of high quality as a release film for rubber in the same manner as the release polyester film for rubber obtained in Example 1. It was.

[Manufacture of polyester film for rubber release]
Polyethylene terephthalate pellets (intrinsic viscosity 0.65 dl / g) are sufficiently dried in vacuum, then supplied to an extruder heated to 280 ° C., extruded into a sheet form from a T-shaped die, and using an electrostatic application casting method. It was wound around a mirror casting drum having a surface temperature of 30 ° C. to be cooled and solidified. The unstretched film was stretched 3.5 times in the longitudinal direction while passing through a heating roll group at 95 ° C. to obtain a uniaxially oriented film.

  The coating solution prepared in Example 1 was applied to both surfaces of this uniaxially oriented film so that the thickness after drying was 0.15 μm. The uniaxially stretched film coated with the coating liquid is guided to the preheating zone while being gripped with a clip, dried at 110 ° C, continuously stretched 3.5 times in the width direction in the heating zone of 125 ° C, and further to 225 ° C. Then, relaxation of 6% in the width direction and heat treatment for 6 seconds were performed to obtain a polyester film for rubber release having a thickness of 50 μm.

Example 3
In Example 2, the separation for rubber was performed in the same manner as in Example 2 except that the polymer wax component (B) was changed to an acrylic wax agent ("ST-200", manufactured by Nippon Shokubai Co., Ltd.). A mold film and a rubber sheet composite were obtained.

  As in Example 2, the release of the release polyester film for rubber was not observed during the production of the rubber sheet composite. Further, the release strength of the release polyester film for rubber from the obtained rubber sheet composite was 0.3 N / 20 mm, and the release polyester film for rubber was the same as the rubber sheet composite obtained in Example 2. The rubber release polyester film obtained in this example was of high quality as a rubber release film in the same manner as the rubber release polyester film obtained in Example 2. It was.

Example 4
In the method of Example 2, the release agent for rubber was carried out in the same manner as in Example 2 except that the antistatic agent (C) was changed to an anionic antistatic agent (“TB214”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). A film and rubber sheet composite was obtained.

  As in Example 2, the release of the release polyester film for rubber was not observed during the production of the rubber sheet composite. Moreover, the peel strength of the release polyester film for rubber from the obtained rubber sheet composite is 0.2 N / 20 mm, and the peelability of the separator film is the same as that of the rubber sheet composite obtained in Example 2. The release polyester film for rubber obtained in this example was high quality as a release film for rubber similar to the release polyester film for rubber obtained in Example 2.

Example 5
In Example 2, except that the polymer-based wax component (B) is changed to 0.2% by mass and the antistatic agent (C) is 0.3% by mass, the same method as in Example 2 is used for rubber. A release film and a rubber sheet composite were obtained.

  As in Example 2, the release of the release polyester film for rubber was not observed during the production of the rubber sheet composite. Moreover, the release strength of the release polyester film for rubber from the obtained rubber sheet composite was 0.05 N / 20 mm, and the release polyester film for rubber obtained in Example 5 also had good release properties. Had.

Example 6
The method of Example 2 was the same as that of Example 2 except that the polymer wax component (B) was changed to 1.3% by mass and the antistatic agent (C) was changed to 1.5% by mass. By the method, a release film for rubber and a rubber sheet composite were obtained.

  The release strength of the release polyester film for rubber (separator film) of the rubber sheet composite obtained in this example was almost 0 N / 20 mm, and the peelability was very good. The release of the release polyester film for rubber sometimes occurred.

Example 7
EPDM (ethylene content: 34% by mass, diene content: 5.8% by mass, “EP21” manufactured by JSR Corporation) as rubber, and zinc salt of 2-mercaptobenzimidazole (“NOCRACK (registered trademark) MBZ”) as anti-aging agent A , Manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) and 4,4- (α, α-dimethylbenzyl) diphenylamine (“NOCRACK (registered trademark) CD”, manufactured by Ouchi Shinsei Chemical Industrial Co., Ltd.) as the anti-aging agent B, respectively. The kneading was carried out in the usual manner with the following composition.

(Composition composition)
EPDM: 100.0 parts by mass, polyethylene glycol (molecular weight 4000): 2.5 parts by mass, stearic acid: 0.5 parts by mass, anti-aging agent A: 1.5 parts by mass, anti-aging agent B: 0.7 parts by mass Parts, phenol formaldehyde resin (manufactured by Sumitomo Chemical Co., Ltd., trade name “Tacchiroll EP-20”): 2.0 parts by mass, MAF carbon (manufactured by Asahi Carbon Co., Ltd.): 30.0 parts by mass, FT carbon (Asahi Carbon Co., Ltd.) 40.0 parts by mass, polybutene (manufactured by Nippon Oil Corporation, trade name “Polybutene HV-300”): 15.0 parts by mass, N, N′-m-phenylene dimaleimide: 1.5 parts by mass 2,5-dimethyl-2,5-di (t-butylperoxy) hexane: 5.0 parts by mass.

  The kneaded rubber was formed into a sheet having a thickness of 3 mm. This unvulcanized rubber sheet is cut into 1 cm square pieces, which are weighed so that the mass ratio to toluene is 30% by mass, and put together with toluene into a stirrer equipped with a vacuum deaerator. The strip was dissolved in toluene by stirring for 15 hours under atmospheric pressure. To this solution, pentaerythritol tetraacrylate was added in an amount of 8 parts by mass with respect to 100 parts by mass of the EPDM rubber. After stirring uniformly, the vacuum deaerator was driven and the gauge pressure was -750 mmHg under vacuum. The mixture was further stirred for 20 minutes to degas.

  Next, the rubber release was performed in the same manner as in Example 2 except that the EPDM rubber solution after defoaming was supplied to a roll coater and the electron beam irradiation was changed so as to irradiate twice with an energy of 200 KV and 15 Mrad. A polyester film and rubber sheet composite was obtained.

  In the same manner as in Example 2, there was no occurrence of lifting of the release polyester film (separator film) for rubber during the production of the rubber sheet composite. The peel strength of the separator film from the obtained rubber sheet composite is 0.1 N / 20 mm, and the peelability of the release polyester film for rubber is the same as that of the rubber sheet composite obtained in Example 2. The release polyester film for rubber obtained in this example was high quality as a release film for rubber similar to the release polyester film for rubber obtained in Example 2.

  The release polyester film for rubber according to the present invention is hardly affected by the cross-linking adhesive force, which is a characteristic of rubber, even when the rubber is subjected to a cross-linking treatment in a state where it is laminated on the surface of an uncross-linked or semi-cross-linked rubber. Also, an increase in peeling force is unlikely to occur. Therefore, it can be suitably used as a fabric film on a rubber surface, a release polyester film for rubber (separate film), or the like.

Claims (2)

A release polyester film for rubber used to protect a rubber layer,
A release polyester for rubber, comprising a release layer containing a resin binder (A), a polymer wax component (B) and an antistatic agent (C) on at least one surface of a polyester base film. the film.   The rubber release polyester film is laminated so that the surface of the release layer is in contact with the surface of the uncrosslinked or semicrosslinked rubber, and the rubber layer after the crosslinking treatment of the uncrosslinked or semicrosslinked rubber is performed, and the release layer. The release polyester film for rubber according to claim 1, which has a peel strength from the mold layer of 0.03 to 1.0 N / 20 mm.