JP5956483B2 - Laminated polyester film - Google Patents

Description

  The present invention relates to a release film, and particularly for applications requiring heat resistance, for example, for transfer such as molding simultaneous transfer, for manufacturing flexible printed wiring boards, for process paper for manufacturing plastic sheets, etc. The present invention relates to a release polyester film suitable as a process film used in the process.

  Conventionally, polyester films represented by polyethylene terephthalate and polyethylene naphthalate have excellent mechanical properties, dimensional stability, flatness, heat resistance, chemical resistance, optical properties, etc., and cost performance. It is used for various purposes. When a polyester film is used as a release film, it has a drawback of poor practicality because of its insufficient release properties for various resins and adhesives. For this reason, a method for laminating a releasable coating film on the surface of a polyester film has been studied. For example, a method of applying and laminating a long chain alkyl group-containing resin on a polyester film surface (Patent Documents 1 and 2) has been proposed.

  On the other hand, the polyester film has a weak point that it is easily charged due to static electricity as a problem common to plastic films. Therefore, there are problems such as poor runnability of the processed product or processed product, the problem of attracting surrounding dust and the like, and the problem of causing trouble in the product due to charging when peeling for process paper. As for suppression of charging of the polyester film, there is a method of providing a coating layer having antistatic performance on the film.

  In relation to the above problems, Patent Documents 3 to 6 propose a polyester film having a coating layer containing a cationic antistatic agent and having good runnability on a coater.

  Examples of applications that use polyester film as a release film include heat and pressure applied to the film during various processes, such as transfer for molding simultaneous transfer, manufacturing of flexible printed wiring plates, and process paper for manufacturing plastic sheets. There is something. When used for these heat-sensitive applications, the release film created by the above method has a problem that the release property of the film deteriorates and the film cannot be removed smoothly, and has excellent heat resistance. There is a need for a release film.

JP 2002-240016 A JP 2006-022136 A JP-A-5-1164 Japanese Patent Laid-Open No. 8-143691 JP 2008-81551 A JP 2008-81552 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is in various processes such as transfer for molding simultaneous transfer, for manufacturing a flexible printed wiring board, for process paper for manufacturing a plastic sheet, etc. An object of the present invention is to provide a release polyester film having excellent antistatic properties as a process film to be used, and having little deterioration of release properties due to heat during processing.

  As a result of intensive studies in view of the above circumstances, the present inventors have found that the above-mentioned problems can be easily solved by a laminated polyester film having a specific configuration, and have completed the present invention.

That is, the gist of the present invention is that a polyester film has a coating layer formed from a coating solution containing a release agent, an antistatic agent, and a blocked isocyanate on at least one side, and the coating layer is kept at 100 ° C. for 1 hour. It exists in the laminated polyester film characterized by the increase rate of the peeling force after heating being 3.0 times or less.

  According to the laminated polyester film of the present invention, when used as a film for various processes such as for production of an antireflection film for transfer, it has excellent antistatic properties, high heat resistance, and depends on heat during processing. A release polyester film with little deterioration in releasability can be provided, and its industrial value is high.

  The polyester film constituting the polyester film in the present invention may have a single layer structure or a multilayer structure, and may have four or more layers as long as the gist of the present invention is not exceeded other than the two-layer or three-layer structure. It may be a multilayer and is not particularly limited. For example, it is possible to change the raw material of the surface layer and the intermediate layer into a three-layer structure for the purpose of effectively improving various properties using a polyester film with high functionality as the surface layer raw material.

  The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyester includes polyethylene terephthalate and the like. On the other hand, the dicarboxylic acid component of the copolyester includes isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxybenzoic acid, etc.), etc. 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexane dimethanol, neopentyl glycol, is mentioned.

  There is no restriction | limiting in particular as a polymerization catalyst of polyester, A conventionally well-known compound can be used, For example, an antimony compound, a titanium compound, a germanium compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound etc. are mentioned.

  In the polyester layer of the film of the present invention, particles can be blended mainly for the purpose of imparting slipperiness and preventing scratches in each step. When the particles are blended, the kind of the particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples thereof include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, sulfuric acid. Examples thereof include inorganic particles such as calcium, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, and benzoguanamine resin. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  Moreover, the average particle diameter of the particle | grains to be used is 5 micrometers or less normally, Preferably it is the range of 0.1-3 micrometers. When the average particle diameter exceeds 5 μm, the surface roughness of the film becomes too rough, which may affect the surface shape of the molding surface to be transferred.

  Furthermore, the content of particles in the polyester layer is usually 5% by weight or less, preferably 0.0003 to 3% by weight. When the particle content exceeds 5% by weight, the transparency of the film may be insufficient.

The shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc.
These series of particles may be used in combination of two or more as required.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage for producing the polyester constituting each layer, but it is preferably added after completion of esterification or transesterification.

  In addition to the above-mentioned particles, conventionally known antioxidants, heat stabilizers, lubricants, dyes, pigments and the like can be added to the polyester film in the present invention as necessary.

  The thickness of the polyester film in the present invention is not particularly limited as long as it can be formed as a film, but is usually 5 to 300 μm, preferably 10 in terms of mechanical strength, handling properties, and productivity. A range of ˜200 μm is preferable.

  Next, although the manufacture example of the polyester film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all. That is, a method is preferred in which pellets obtained by drying the polyester raw material described above are extruded as a molten sheet from a die using an extruder and cooled and solidified with a cooling roll to obtain an unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, the film is stretched in the direction perpendicular to the first stretching direction. In that case, the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. is there. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  In the present invention, the simultaneous biaxial stretching method can be adopted for the production of the polyester film constituting the laminated polyester film. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is usually stretched and oriented in the machine direction and the width direction at a temperature controlled normally at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear driving method can be employed.

  Next, formation of the coating layer which comprises the laminated polyester film in this invention is demonstrated. Regarding the coating layer, it may be provided by in-line coating which treats the film surface during the process of forming a polyester film, or offline coating which is applied outside the system on a once produced film may be adopted. More preferably, it is formed by in-line coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film, and specifically, a method of coating at any stage from melt extrusion of the polyester to heat setting after stretching and winding up. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, and a film after heat setting and before winding. Although not limited to the following, for example, in sequential biaxial stretching, a method of stretching in the transverse direction after coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) is particularly excellent. According to this method, film formation and coating layer formation can be performed at the same time. In order to perform stretching after coating, the thickness of the coating layer can be changed depending on the stretching ratio, and thin film coating can be performed more easily than an off-line coating film. Further, by providing the coating layer on the film before stretching, the coating layer can be stretched together with the base film, whereby the coating layer can be firmly adhered to the base film. Furthermore, in the production of a biaxially stretched polyester film, the film can be restrained in the longitudinal and lateral directions by stretching while gripping the film end with a clip, etc. High temperature can be applied while maintaining the properties. Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer can be improved, and the coating layer and the base film can be more firmly adhered to each other. Furthermore, a strong coating layer can be obtained.

  In the present invention, it is an essential requirement to have a coating layer formed from a coating solution containing an antistatic agent, a release agent, and an isocyanate compound.

  The coating layer in the present invention has a release performance suitable as a process film used in various processes such as transfer for molding simultaneous transfer, for manufacturing flexible printed wiring boards, for process paper for manufacturing plastic sheets, etc. It is provided in order to improve.

  The release agent used for forming the coating layer of the film of the present invention is used for improving the release property of the film, and is not particularly limited, and a conventionally known release agent can be used. Examples thereof include long-chain alkyl compounds, waxes, fluorine compounds, and silicone compounds. Among these, a long-chain alkyl compound is preferable from the viewpoint of little contamination and excellent releasability. These release agents may be used alone or in combination.

  The long-chain alkyl compound is a compound having a linear or branched alkyl group having 6 or more, preferably 8 or more, and more preferably 12 or more carbon atoms. Examples of the alkyl group include hexyl group, octyl group, decyl group, lauryl group, octadecyl group, and behenyl group. Examples of the compound having an alkyl group include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, and long-chain alkyl group-containing ether compounds. In view of heat resistance and contamination, a polymer compound is preferable. Further, from the viewpoint of effectively obtaining releasability, a polymer compound having a long-chain alkyl group in the side chain is more preferable.

  The polymer compound having a long-chain alkyl group in the side chain can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group. Examples of the reactive group include a hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Examples of the compound having such a reactive group include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, a reactive group-containing polyester resin, and a reactive group-containing poly (meth) acrylic resin. Among these, polyvinyl alcohol is preferable in view of releasability and ease of handling.

  Examples of the compound having an alkyl group capable of reacting with the reactive group include, for example, long-chain alkyl group-containing isocyanates such as hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, and behenyl isocyanate, hexyl chloride, and octyl chloride. Long chain alkyl group-containing acid chlorides such as decyl chloride, lauryl chloride, octadecyl chloride, and behenyl chloride, long chain alkyl group-containing amines, and long chain alkyl group-containing alcohols. Among these, long chain alkyl group-containing isocyanates are preferable, and octadecyl isocyanate is particularly preferable in consideration of releasability and ease of handling.

  In addition, a polymer compound having a long-chain alkyl group in the side chain can also be obtained by copolymerization of a long-chain alkyl (meth) acrylate polymer or a long-chain alkyl (meth) acrylate and another vinyl group-containing monomer. . Examples of the long-chain alkyl (meth) acrylate include hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate, and behenyl (meth) acrylate. It is done.

  The wax is a wax selected from natural waxes, synthetic waxes, and blended waxes thereof. Natural waxes are plant waxes, animal waxes, mineral waxes, and petroleum waxes. Examples of plant waxes include candelilla wax, carnauba wax, rice wax, wood wax, and jojoba oil. Animal waxes include beeswax, lanolin, and whale wax. Examples of the mineral wax include montan wax, ozokerite, and ceresin. Examples of petroleum wax include paraffin wax, microcrystalline wax, and petrolatum. Synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, acid amides, amines, imides, esters, and ketones. As synthetic hydrocarbons, Fischer-Tropsch wax (also known as Sazoir wax) and polyethylene wax are famous, but in addition to this, low molecular weight polymers (specifically, polymers having a viscosity number average molecular weight of 500 to 20000) Some of the following polymers are also included. That is, there are polypropylene, ethylene / acrylic acid copolymer, polyethylene glycol, polypropylene glycol, polyethylene glycol and polypropylene glycol block or graft conjugate. Examples of the modified wax include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. The derivative herein is a compound obtained by any of purification, oxidation, esterification, saponification treatment, or a combination thereof. Hydrogenated waxes include hardened castor oil and hardened castor oil derivatives.

  The fluorine compound is a compound containing a fluorine atom in the compound. Organic fluorine compounds are preferably used in terms of the appearance of coating by in-line coating, and examples thereof include perfluoroalkyl group-containing compounds, polymers of olefin compounds containing fluorine atoms, and aromatic fluorine compounds such as fluorobenzene. . In view of heat resistance and contamination, a polymer compound is preferable.

  The silicone compound is a compound having a silicone structure in the molecule, and examples thereof include silicone emulsion, acrylic graft silicone, silicone graft acrylic, amino-modified silicone, perfluoroalkyl-modified silicone, and alkyl-modified silicone. In view of heat resistance and contamination, it is preferable to contain a curable silicone resin. As the type of the curable silicone resin, any of the curing reaction types such as an addition type, a condensation type, an ultraviolet curable type, and an electron beam curable type can be used.

  The antistatic agent used for forming the coating layer of the film of the present invention is used for lowering the surface resistance of the film surface, and there is no particular limitation, and a conventionally known antistatic agent can be used. A polymer type antistatic agent is preferred because of its good heat resistance and moist heat resistance. Examples of the polymer type antistatic agent include compounds having an ammonium group, polyether compounds, sulfonic acid compounds, betaine compounds, and conductive polymers.

  The compound having an ammonium group used for forming the coating layer of the film of the present invention is a compound having an ammonium group in the molecule, and examples thereof include aliphatic amines, alicyclic amines, and ammonium amines of aromatic amines. . The compound having an ammonium group is preferably a polymer compound, for example, a polymer compound having an ammonium group from a polymer obtained by polymerizing a monomer containing an addition polymerizable ammonium group or a precursor of an ammonium group such as an amine, and the like. And are preferably used. As the polymer, a monomer containing an addition polymerizable ammonium group or a precursor of an ammonium group such as an amine may be polymerized alone, or it may be a copolymer of a monomer containing these and another monomer. May be.

  Specific examples of the polymer of the compound having an ammonium group include, but are not limited to, a polymer containing a constituent represented by the following formula (1) or the following formula (2). It is done. A single polymer or copolymer, or a plurality of other components may be copolymerized.

In the above formula (1), R ² is —O—, —NH— or —S—, R ³ is an alkylene group, or other structure capable of forming the structure of formula (1), R ¹ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group, a phenyl group or the like, and these alkyl group and phenyl group may be substituted with the following groups. Substitutable groups include, for example, hydroxyl group, amino group, amide group, ester group, alkoxy group, phenoxy group, naphthoxy group, thioalkoxy group, thiophenoxy group, cycloalkyl group, trialkylammonium alkyl group, cyano group, Halogen.

In said formula (2), R < ¹ >, R < ² > is respectively independently an alkyl group, a phenyl group, etc., These alkyl groups and a phenyl group may be substituted by the group shown below. Substitutable groups include, for example, hydroxyl group, amino group, amide group, ester group, alkoxy group, phenoxy group, naphthoxy group, thioalkoxy group, thiophenoxy group, cycloalkyl group, trialkylammonium alkyl group, cyano group, Halogen. R ¹ and R ² may be chemically bonded, for example, — (CH ₂ ) m— (m = 2 to 5), —CH (CH ₃ ) CH (CH ₃ ) —, -CH = CH-CH = CH - , - CH = CH-CH = N -, - CH = CH-N = C -, - CH 2 OCH 2 -, - (CH 2) 2 O (CH 2) 2 - Etc.

X ⁻ in the above formulas (1) and (2) can be appropriately selected within a range not impairing the gist of the present invention. For example, alkyl sulfate ion, alkyl sulfonate ion, halogen ion, phosphate, nitrate, carboxylate and the like can be mentioned.

The polymer having the component represented by the above formula (1) is preferably excellent in transparency of the obtained coating layer, and has an advantage that it can be made relatively low in peeling force when used in combination with a release agent. is there. In view of heat resistance and environmental aspects, X ⁻ is preferably not halogen.

  A compound represented by Formula 2 and other ammonium bases in the polymer main skeleton are excellent in heat resistance and are preferable.

  Moreover, the number average molecular weight of the compound which has an ammonium group is 1000-500000, Preferably it is 2000-350,000, More preferably, it is 5000-200000. When the molecular weight is less than 1000, the strength of the coating film may be weakened or the heat stability may be poor. On the other hand, when the molecular weight exceeds 500,000, the viscosity of the coating solution increases, and the handleability and applicability may deteriorate.

  Examples of polyether compounds include polyethylene oxide, polyether ester amide, acrylic resins having polyethylene glycol in the side chain, and the like.

  The sulfonic acid compounds are compounds containing sulfonic acid or sulfonate in the molecule, and examples thereof include polystyrene sulfonic acid.

  Examples of the conductive polymer include polythiophene-based, polyaniline-based, polypyrrole-based, and polyacetylene-based polymers. Among them, for example, polythiophene-based polymers using poly (3,4-ethylenedioxythiophene) in combination with polystyrene sulfonic acid. Are preferably used.

  In the present invention, the isocyanate compound used in the formation of the coating layer is used to make the coating layer strong and to provide stable release performance and antistatic performance. As a result of further investigations, it was found that in addition to these performances, mold release performance can be maintained even after heat treatment. Usually, by heat treatment, the mold release performance deteriorates, the peeling force becomes heavy, and it is difficult to develop the application through the heating process, but by using an isocyanate compound in combination with the mold release agent It has been found that the peeling force due to heating can be reduced.

  The isocyanate compound used for forming the coating layer of the film of the present invention is a compound having an isocyanate derivative structure typified by isocyanate or blocked isocyanate. Examples of isocyanate include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate, and aromatic rings such as α, α, α ′, α′-tetramethylxylylene diisocyanate. Aliphatic isocyanates such as aliphatic isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate Ne Alicyclic isocyanates such as bets are exemplified. Reaction products of these isocyanates with various polymers and compounds may be used. Further, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays. Further, when an aqueous coating solution is used, it is more preferably a blocked isocyanate.

  When used in the state of blocked isocyanate, the blocking agent includes, for example, bisulfites, phenolic compounds such as phenol, cresol, and ethylphenol, and alcohols such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol. Compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, lactam compounds such as ε-caprolactam and δ-valerolactam , Amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, formaldehyde, acetoald Examples include oxime compounds such as oxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more. Among these, an active methylene compound is preferable from the viewpoint that the peeling property hardly changes even after heating.

  In addition, the isocyanate compound in the present invention may be used alone, or may be used as a mixture or bond with various polymers. In the sense of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or a bond with a polyester resin or a urethane resin.

  In the formation of the coating layer of the film of the present invention, various polymers may be used in combination in order to improve the coating appearance, transparency, and release properties.

  Specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches and the like. . Among these, acrylic resin, polyvinyl alcohol, polyester resin, and urethane resin are preferable in terms of easy release control, and acrylic resin is particularly preferable among them.

  The acrylic resin is a polymer composed of a polymerizable monomer including acrylic and methacrylic monomers. These may be either homopolymers or copolymers, and copolymers with polymerizable monomers other than acrylic and methacrylic monomers. Moreover, the copolymer of these polymers and other polymers (for example, polyester, polyurethane, etc.) is also included. For example, a block copolymer or a graft copolymer. Alternatively, a polymer (possibly a mixture of polymers) obtained by polymerizing a polymerizable monomer in a polyester solution or a polyester dispersion is also included. Similarly, a polymer obtained by polymerizing a polymerizable monomer in a polyurethane solution or a polyurethane dispersion (sometimes a mixture of polymers) is also included. Similarly, a polymer (in some cases, a polymer mixture) obtained by polymerizing a polymerizable monomer in another polymer solution or dispersion is also included. Moreover, in order to improve adhesiveness more, it is also possible to contain a hydroxyl group and an amino group.

  The polymerizable monomer is not particularly limited, but particularly representative compounds include, for example, various carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Monomers, and salts thereof; such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxyl fumarate, monobutyl hydroxy itaconate Various hydroxyl group-containing monomers; various (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate; (Meth) acrylamide, Various nitrogen-containing compounds such as acetone acrylamide, N-methylol acrylamide or (meth) acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, and various vinyls such as vinyl propionate Esters; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, etc .; phosphorus-containing vinyl monomers; various vinyl halides such as vinyl chloride and biridene chloride Various conjugated dienes such as butadiene.

  Polyvinyl alcohol is a compound having a polyvinyl alcohol moiety. For example, conventionally known polyvinyl alcohol can be used, including modified compounds that are partially acetalized or brachiralized with respect to polyvinyl alcohol. The degree of polymerization of polyvinyl alcohol is not particularly limited, but is usually 100 or more, preferably in the range of 300 to 40,000. When the degree of polymerization is less than 100, the water resistance of the coating layer may decrease. The saponification degree of polyvinyl alcohol is not particularly limited, but is usually 70 mol% or more, preferably in the range of 70 to 99.9 mol%, more preferably 80 to 97 mol%, and particularly preferably 86 to 97 mol%. A saponified polyvinyl acetate of 95 mol% is practically used.

  The polyester resin includes, for example, those composed of the following polyvalent carboxylic acid and polyvalent hydroxy compound as main constituent components. That is, as the polyvalent carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6 -Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid monopotassium salt and ester-forming derivatives thereof can be used. As the polyvalent hydroxy compound, ethylene Recall, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol , Neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol Polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like can be used. One or more compounds may be appropriately selected from these compounds, and a polyester resin may be synthesized by a conventional polycondensation reaction.

  The urethane resin is a polymer compound having a urethane bond in the molecule. Usually, urethane resin is prepared by reaction of polyol and isocyanate. Examples of the polyol include polycarbonate polyols, polyester polyols, polyether polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

  Polycarbonate polyols are obtained from a polyhydric alcohol and a carbonate compound by a dealcoholization reaction. Examples of the polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane. Diol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decane Diol, neopentyl glycol, 3-methyl-1,5-pentanediol, 3,3-dimethylol heptane and the like can be mentioned. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of the polycarbonate-based polyols obtained from these reactions include poly (1,6-hexylene) carbonate, poly (3- And methyl-1,5-pentylene) carbonate.

  Polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides. Product and polyhydric alcohol (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol 2-methyl-2-propyl-1 3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexane Diol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamine, lactone diol, etc.).

  Examples of the polyisocyanate compound used for obtaining the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, α ′. -Aliphatic diisocyanates having aromatic rings such as tetramethylxylylene diisocyanate, aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Methanzi Cyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination.

  A chain extender may be used when synthesizing the urethane resin, and the chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group. Alternatively, a chain extender having two amino groups can be mainly used.

  Examples of the chain extender having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, and esters such as neopentyl glycol hydroxypivalate. And glycols such as glycols.

  Examples of the chain extender having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3- Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- Aliphatic diamines such as decane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropylidenecyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, 1, 3-Bisaminomethylcyclohexa And alicyclic diamines such as

  The urethane resin in the present invention may use a solvent as a medium, but preferably uses water as a medium. In order to disperse or dissolve the urethane resin in water, there are a forced emulsification type using an emulsifier, a self-emulsification type in which a hydrophilic group is introduced into the urethane resin, and a water-soluble type. In particular, the self-emulsification type in which an ionic group is introduced into the structure of the urethane resin to form an ionomer is preferable because of excellent storage stability of the liquid and water resistance and transparency of the resulting coating layer.

  Examples of the ionic group to be introduced include various groups such as a carboxyl group, sulfonic acid, phosphoric acid, phosphonic acid, and quaternary ammonium salt, and a carboxyl group is preferred.

  As a method for introducing a carboxyl group into a urethane resin, various methods can be taken in each stage of the polymerization reaction. For example, there are a method of using a carboxyl group-containing resin as a copolymer component during prepolymer synthesis, and a method of using a component having a carboxyl group as one component such as polyol, polyisocyanate, and chain extender. In particular, a method in which a desired amount of carboxyl groups is introduced using a carboxyl group-containing diol depending on the amount of this component charged is preferred. For example, dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid and the like are copolymerized with a diol used for polymerization of a urethane resin. Can do.

  The carboxyl group is preferably in the form of a salt neutralized with ammonia, amine, alkali metal, inorganic alkali or the like. Particularly preferred are ammonia, trimethylamine and triethylamine.

  In such a polyurethane resin, a carboxyl group from which a neutralizing agent is removed in a drying step after coating can be used as a crosslinking reaction point by another crosslinking agent. Thereby, it is possible to further improve the durability, solvent resistance, water resistance, blocking resistance, and the like of the obtained coating layer, as well as excellent stability in a liquid state before coating.

  In the formation of the coating layer of the film of the present invention, a crosslinking agent other than an isocyanate compound is used in combination for improving the coating appearance and transparency, controlling the release property and antistatic property, and improving the strength of the coating layer. Is also possible.

  As the crosslinking agent, various conventionally known crosslinking agents can be used, and examples thereof include melamine compounds, oxazoline compounds, epoxy compounds, carbodiimide compounds, silane coupling compounds, and the like. Among these, melamine compounds and oxazoline compounds are preferable from the viewpoint of the strength of the coating layer, and melamine compounds are particularly preferable from the viewpoint of antistatic properties.

  The melamine compound is a compound having a melamine skeleton in the compound. For example, an alkylolized melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and these Mixtures can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Moreover, as a melamine compound, either a monomer or a multimer more than a dimer may be sufficient, or a mixture thereof may be used. Further, a product obtained by co-condensing urea or the like with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

  The oxazoline compound is a compound having an oxazoline group in the molecule, and a polymer containing an oxazoline group is particularly preferable, and can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers 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 mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide, N-alkyl ( (Meth) acrylamide, N, N-dialkyl (meth) acrylamide, As the alkyl group, unsaturated amides such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group and cyclohexyl group); vinyl acetate Vinyl esters such as vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride And α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like, and one or more of these monomers can be used.

  Moreover, in the range which does not impair the main point of this invention, it is also possible to use particle | grains together for the purpose of the formation of the coating layer of the film of this invention for the purpose of the blocking property of a coating layer, slipperiness improvement, etc.

  Furthermore, as long as it does not impair the gist of the present invention, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an ultraviolet absorber, an antioxidant, a foaming agent, It is also possible to use dyes, pigments and the like in combination.

  As a ratio with respect to all the non-volatile components in the coating liquid for forming the coating layer of the present invention, the release agent is usually in the range of 5 to 90% by weight, preferably 10 to 75% by weight, and more preferably 15 to 40% by weight. is there. If the amount is less than 5% by weight, sufficient release performance may not be obtained. If the amount exceeds 90% by weight, sufficient heat resistance and antistatic property may not be obtained due to the small amount of other components. There is.

  The ratio of the antistatic agent is usually from 5 to 90% by weight, preferably from 10 to 75% by weight, more preferably from 25 to 50% by weight, based on the total amount of non-volatile components in the coating solution for forming the coating layer of the present invention. is there. When the amount is less than 5% by weight, the antistatic property may not be sufficient. When the amount exceeds 90% by weight, sufficient heat resistance and releasability may not be obtained because other components are small.

  As a ratio with respect to all the non-volatile components in the coating liquid which forms the coating layer which comprises the laminated polyester film in this invention, an isocyanate type compound is 2-90 weight% normally, Preferably it is 5-70 weight%, More preferably, 15- It is in the range of 40% by weight, particularly preferably 20-30% by weight. When the amount is less than 2% by weight, there is a possibility that the release performance after heating may be greatly deteriorated. When the amount exceeds 90% by weight, sufficient heat resistance and releasability cannot be obtained because there are few other components. there is a possibility. In addition, it has been found out that the antistatic property may deteriorate if the amount is large.

  As a ratio with respect to all the non-volatile components in the coating liquid which forms the coating layer which comprises the laminated polyester film in this invention, a polymer is 80 weight% or less normally, Preferably it is 5-70 weight%, More preferably, it is 15-40 weight%. Range. By using it in the above-mentioned range, it becomes easy to improve the coating appearance and adjust the releasability and antistatic property.

  As a ratio with respect to all the non-volatile components in the coating liquid which forms the coating layer which comprises the laminated polyester film in this invention, crosslinking agents other than an isocyanate type compound are 50 weight% or less normally, Preferably it is 3-40 weight%, More preferably, Is in the range of 5 to 25% by weight. By using in the above range, it becomes easy to improve the strength of the coating layer and adjust the antistatic property.

  Analysis of components in the coating layer can be performed by analysis such as TOF-SIMS and ESCA.

  When providing a coating layer by in-line coating, the above-mentioned series of compounds is applied as an aqueous solution or dispersion, and the coating solution adjusted to a solid content concentration of about 0.1 to 50% by weight as a guide is applied onto the polyester film. It is preferable to produce a laminated polyester film. Moreover, in the range which does not impair the main point of this invention, a small amount of organic solvents may be contained in the coating liquid for the purpose of improving dispersibility in water, improving film-forming properties, and the like. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

  Regarding the laminated polyester film in the present invention, the thickness of the coating layer provided on the polyester film is usually 0.003 to 1 μm, preferably 0.005 to 0.5 μm, more preferably 0.01 to 0.2 μm. It is. When the film thickness exceeds 1 μm, the appearance and transparency may be deteriorated, and when the film thickness is less than 0.005 μm, sufficient releasability may not be obtained.

  Examples of the method for forming the coating layer of the present invention include gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, and impregnation. Conventionally known coating methods such as coat, kiss coat, spray coat, calendar coat, and extrusion coat can be used.

  In the present invention, the drying and curing conditions for forming the coating layer on the polyester film are not particularly limited. For example, when the coating layer is provided by off-line coating, it is usually 3 to 40 at 80 to 200 ° C. The heat treatment may be performed for 2 seconds, preferably 100 to 180 ° C. for 3 to 40 seconds.

  On the other hand, when the coating layer is provided by in-line coating, heat treatment is usually performed at 70 to 270 ° C. for 3 to 200 seconds as a guide.

  Further, irrespective of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as required. The polyester film constituting the laminated polyester film in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  The peeling force before heating of the coating layer in the present invention is preferably 2000 mN / cm or less, more preferably 1500 mN / cm or less, and still more preferably 1000 mN / cm or less. By setting it as the said range, a peeling operation | work will become easy.

  In the present invention, the peel strength after heating the coating layer at 100 ° C. for 1 hour is preferably 3500 mN / cm or less, more preferably 2900 mN / cm or less. By setting it as the said range, peeling can be fully performed even after heat processing.

  In the present invention, it is preferable that the peeling force of the coating layer has a small change before and after heating. Usually, the peeling force tends to increase due to heating. If the increase is small, the peeling characteristics after heating can be predicted from the peeling characteristics before heating, and the method of peeling work is adjusted to the same level as before heating. It becomes possible to do. That is, the rate of increase in peel strength after heating at 100 ° C. for 1 hour is essential to be 3.0 times or less, preferably 2.8 times or less, more preferably 2.5 times or less, particularly Preferably it is the range of 2.0 times or less.

The surface resistance value of the coating layer in the present invention is preferably 1 × 10 ¹³ Ω or less, more preferably 1 × 10 ¹² Ω or less, and further preferably 1 × 10 ¹¹ Ω or less. By setting it as the said range, it can be set as the film in which peeling electrification does not occur easily.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Method for measuring the intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. And dissolved at 30 ° C.

(2) Method for measuring film thickness of coating layer The surface of the coating layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by ultramicrotomy stained with RuO _4, a coating layer cross-section was measured by using a TEM (Hitachi High Technologies Corporation H-7650, accelerating voltage 100 V).

(3) Measuring method of peel force before heating of release film Adhesive tape (“No. 31B” manufactured by Nitto Denko Corporation) is pressure-bonded once with a 2 kg rubber roller on the coating layer surface, and left at room temperature for 1 hour. The peel force was measured. The peel force was “Ezgraph” manufactured by Shimadzu Corporation, and was peeled 180 ° under a condition of a tensile speed of 300 mm / min, and the peel force at that time was measured.

(4) Measuring method of peel force after heating of release film After pressure-bonding adhesive tape (“No. 31B” manufactured by Nitto Denko Corporation) 1 reciprocating with a 2 kg rubber roller on the coating layer surface, in a 100 degree oven. And heated for 1 hour. Thereafter, the peel force after standing at room temperature for 1 hour was measured. The peel force was “Ezgraph” manufactured by Shimadzu Corporation, and was peeled 180 ° under a condition of a tensile speed of 300 mm / min, and the peel force at that time was measured.

(5) Evaluation of heating peeling force increase rate Using the peeling force measured in the above (3) and (4), heating peeling force increase rate = (post-heating peeling force ÷ heating pre-heating peeling force) The rate was calculated.

(6) Measuring method of surface resistance value Using a high resistance measuring instrument manufactured by Hewlett-Packard Japan: HP4339B and measuring electrode: HP16008B, the sample was conditioned in a measurement atmosphere of 23 ° C. and 50% RH for 30 minutes, and then the surface resistance value was measured. Was measured.

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (A)>
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst is placed in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. After adding 0.04 part by weight of ethyl acid phosphate to this reaction mixture, 0.04 part by weight of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.63 due to a change in stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the obtained polyester (A) was 0.63.

<Method for producing polyester (B)>
In the polyester (A) production method, after adding 0.04 part by weight of ethyl acid phosphate, 0.2 part by weight of silica particles having an average particle diameter of 2 μm and 0.04 part by weight of antimony trioxide are added to obtain the intrinsic viscosity. A polyester (B) was obtained using the same method as the production method of the polyester (A) except that the polycondensation reaction was stopped at a time corresponding to 0.65. The obtained polyester (B) had an intrinsic viscosity of 0.65.

Examples of compounds constituting the coating layer are as follows.
(Example compounds)
・ Releasing agent (long-chain alkyl compound): (I)
To a four-necked flask, 200 parts of xylene and 600 parts of octadecyl isocyanate were added and heated with stirring. From the time when xylene began to reflux, 100 parts of polyvinyl alcohol having an average degree of polymerization of 500 and a degree of saponification of 88 mol% was added in small portions over a period of about 2 hours. After the addition of polyvinyl alcohol, the reaction was completed by further refluxing for 2 hours. When the reaction mixture was cooled to about 80 ° C. and added to methanol, the reaction product was precipitated as a white precipitate. This precipitate was filtered off, added with 140 parts of xylene, and heated to dissolve completely. After repeating the operation of adding methanol again to precipitate several times, the precipitate was washed with methanol and dried and ground.

・ Antistatic agent: (IIA)
A polymer having a number average molecular weight of 50,000, comprising a constitutional unit of the following formula 2, wherein the counter ion is a methanesulfonate ion

・ Antistatic agent: (IIB)
Polymer polymerized with the following composition having a pyrrolidinium ring in the main chain: Diallyldimethylammonium chloride / dimethylacrylamide / N-methylolacrylamide = 90/5/5 (mol%). Number average molecular weight 30000

Active methylene block polyisocyanate: (IIIA)
1000 parts of hexamethylene diisocyanate was stirred at 60 ° C., and 0.1 part of tetramethylammonium capryate was added as a catalyst. After 4 hours, 0.2 part of phosphoric acid was added to stop the reaction, and an isocyanurate type polyisocyanate composition was obtained. 100 parts of the obtained isocyanurate type polyisocyanate composition, 42.3 parts of methoxypolyethylene glycol having a number average molecular weight of 400, and 29.5 parts of propylene glycol monomethyl ether acetate were charged and maintained at 80 ° C. for 7 hours. Thereafter, the reaction solution temperature was kept at 60 ° C., 35.8 parts of methyl isobutanoyl acetate, 32.2 parts of diethyl malonate, and 0.88 part of 28% methanol solution of sodium methoxide were added and kept for 4 hours. Block polyisocyanate obtained by adding 58.9 parts of n-butanol and maintaining the reaction solution temperature at 80 ° C. for 2 hours, and then adding 0.86 part of 2-ethylhexyl acid phosphate.

・ Amine block isocyanate: (IIIB)
100 parts of triisocyanurated hexamethylene diisocyanate was heated to 50 ° C. under nitrogen, and 58.5 parts of methyl isobutyl ketone was added. Thereafter, 83.5 parts of di-n-butylamine was added while maintaining the reaction solution temperature at 60 to 70 ° C. After the addition, the block polyisocyanate obtained by maintaining at 75 ° C. for 1 hour and adding 2.0 parts of n-butanol

・ Acrylic resin: (IV)
Emulsion polymer of ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (% by weight) (emulsifier: anionic surfactant)

・ Hexamethoxymethylolmelamine: (VA)
・ Epoxy compounds: (VB)

Example 1:
The mixed raw materials obtained by mixing the polyesters (A) and (B) at a ratio of 90% and 10%, respectively, are used as the outermost layer (surface layer) raw material, and only the polyester (A) is used as the intermediate layer raw material in two extruders. Each is supplied, melted at 285 ° C., and then coextruded in a layer configuration of two types and three layers (surface layer / intermediate layer / surface layer = 1: 8: 1 discharge amount) on a cooling roll set at 40 ° C. Cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.4 times in the longitudinal direction at a film temperature of 85 ° C. using the difference in peripheral speed of the roll, and then the coating solution 1 shown in Table 1 below was applied to one side of the longitudinally stretched film, which was led to a tenter The film was stretched 4.3 times at 110 ° C. in the transverse direction, heat treated at 225 ° C., then relaxed by 2% in the transverse direction, and having a release layer with a film thickness (after drying) of 0.03 μm A polyester film was obtained.

  When the releasability was evaluated for the obtained polyester film, it was good before and after heating, and the rate of increase in peel strength due to heating was small. The properties of this film are shown in Table 2 below.

Examples 2-10:
In Example 1, it manufactured similarly to Example 1 except having changed the coating agent composition into the coating agent composition shown in Table 1, and obtained the polyester film. The finished polyester film was as shown in Table 2. The peel force was low and the release property was good.

Comparative Example 1:
In Example 1, it manufactured like Example 1 except not providing an application layer, and obtained the polyester film. When the completed laminated polyester film was evaluated, it was as shown in Table 2, and the heat peeling force was high and the releasability was poor.

Comparative Examples 2-6:
In Example 1, it manufactured similarly to Example 1 except having changed the coating agent composition into the coating agent composition shown in Table 1, and obtained the polyester film. When the completed laminated polyester film was evaluated, it was as shown in Table 2. The release property before heating and after heating was inferior, and the change in peel strength due to heating was large.

  The release film of the present invention is particularly heat-resistant, for example, as a process film used in various processes such as transfer for molding simultaneous transfer, for manufacturing flexible printed wiring boards, and for process paper for manufacturing plastic sheets. Can be suitably used in applications requiring the above.

Claims (1)

The polyester film has a coating layer formed from a coating solution containing a release agent, an antistatic agent, and a blocked isocyanate on at least one side of the polyester film, and the peeling force increases after heating the coating layer at 100 ° C. for 1 hour. A laminated polyester film having a rate of 3.0 times or less.