JP2017144713A - Laminate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film that is suitable for use in the production processes of various image display devices, particularly, suitable for use in an adhesive for a polarizing plate and a separator thereof, and an adhesive for a polarizing plate protection film and a protection film thereof.SOLUTION: A laminate film has a release layer and an adhesive layer put on, in this order, at least one side of a polyester film, the release layer comprising a long-chain alkyl group-containing compound and a crosslinking agent.SELECTED DRAWING: None

Description

  The present invention relates to a laminated film, and is used, for example, for a manufacturing process of an image display device, and particularly suitable as an adhesive for a polarizing plate and its separator, and an adhesive for a protective film for a polarizing plate and its protective film. The laminated film used for is provided.

  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.

  As an example of an application using a polyester film, a separator or a surface protective film used in a manufacturing process of an image display device or the like can be given. In an image display device such as a liquid crystal display or a touch panel, various optical films such as a polarizing plate are laminated via an adhesive layer for controlling and adjusting the vibration direction and phase difference of light. In these optical films, separators are used for the purpose of protecting the adhesive surface from scratches and dirt in the manufacturing process using these optical films, and surface protective films and the like are affixed for the purpose of preventing scratches and dirt that occur during processing and transport processes. Used in a combined state.

  As a method of processing the adhesive layer into an optical member such as a polarizing plate, for example, an adhesive solution in which an adhesive substance is dissolved or dispersed in a solvent composed of an appropriate solvent alone or a mixture is applied to the surface of the polyester film. There is a method in which the adhesive layer is bonded to the optical member, and then the polyester film is removed to transfer the adhesive layer onto the optical member. Thereafter, another optical member such as an image display device is bonded to the exposed surface of the adhesive layer. With this method, it is possible to prevent the polarizing plate from being deteriorated or deformed by the solvent or heat used when processing the adhesive layer, and the polyester film should also be used as a separator to protect the surface of the adhesive layer. Is possible.

  When a polyester film is used for such an application, since the releasability for various pressure-sensitive adhesives is insufficient, a method for laminating a releasable coating film on the surface of the polyester film has been conventionally studied. For example, a method of applying and laminating a silicone composition typified by polydimethylsiloxane on the surface of a polyester film (Patent Document 1) has been proposed.

  However, the silicone-based release film has a problem that the silicone component is transferred to the adhesive layer, the adhesive strength is lowered, and a defect is caused when the adhesive layer is bonded in a subsequent process.

  As a releasable coating film using a material other than the silicone composition, a method of applying and laminating wax (Patent Document 2) has also been proposed. However, in the case of a releasable coating film made of wax, since the releasability is poor, the adhesive layer may not be transferred onto the optical member such as a polarizing plate, and may remain on the polyester film, resulting in production efficiency. I have a problem that causes a decline. From these viewpoints, a laminated film having a releasable coating film using a material other than a silicone composition and wax, which is used for bonding an optical member of an image display device and can transfer an adhesive layer to the optical member. It has been demanded.

JP 2009-143091 A JP 2004-209756 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is that it is suitably used as a pressure-sensitive adhesive for a polarizing plate and its separator, and a pressure-sensitive adhesive for a protective film for a polarizing plate and its protective film. The present invention provides a laminated film in which no silicone composition is transferred to the layer.

  As a result of intensive studies in view of the above circumstances, the present inventors have found that the use of a laminated film having a specific configuration can easily solve the above-described problems, and have completed the present invention.

  That is, the gist of the present invention is a laminated film in which a release layer and an adhesive layer are laminated in this order on at least one surface of a polyester film, and the release layer contains a long-chain alkyl group-containing compound and a crosslinking agent. It exists in the laminated film characterized by this.

  According to the laminated film of the present invention, when used for the manufacturing process of an image display device, the adhesive layer can be transferred to the optical member, and a laminated film in which the silicone composition does not migrate to the adhesive layer is provided. And its industrial value is high.

  The polyester film constituting the laminated 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.

  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.

  From the viewpoint of forming a film that can withstand various processing conditions, it is preferable that the mechanical strength and heat resistance (dimensional stability by heating) are high, and for that purpose, it is preferable that the copolymer polyester component is small. Specifically, the proportion of the monomer forming the copolyester in the polyester film is preferably in the range of 10 mol% or less, more preferably 5 mol% or less, and more preferably produced as a by-product during homopolyester polymerization. It is a grade which contains the diether component of 3 mol% or less which is a grade which will carry out. In view of mechanical strength and heat resistance, a more preferable form of polyester is more preferably a film formed from polyethylene terephthalate or polyethylene naphthalate, which is polymerized from terephthalic acid and ethylene glycol, among the above compounds. In consideration of ease of handling and handling properties as a surface protective film, a film formed from polyethylene terephthalate is more preferable.

  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. Among these, titanium compounds and germanium compounds have high catalytic activity and can be polymerized in a small amount, and since the amount of metal remaining in the film is small, the brightness of the film is high and inspection is performed through the film. It is preferable from the viewpoint of visibility. Furthermore, since a germanium compound is expensive, it is more preferable to use a titanium compound.

  In the polyester layer of the film of the present invention, it is preferable to blend particles mainly for the purpose of imparting slipperiness and preventing scratches in each step. When there are no particles or when there are few particles, the transparency of the film becomes high and a good film is obtained, but the slipperiness may be insufficient, so that the film tends to be scratched.

  When blending the particles, 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 include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate. Inorganic particles such as calcium sulfate, 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. In addition, it is also possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed during the polyester production process.

  In the case where particles are contained in the polyester film, the structure is preferably three or more layers from the viewpoint of ensuring transparency without deteriorating the slipperiness, and further considering the ease of production, it is a three-layer structure. Is more preferable, and the structure containing the particles in the outermost layer is optimal.

  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 becomes like this. Preferably it is 5 micrometers or less, More 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 particle content in the polyester layer is preferably 5% by weight or less, more preferably in the range of 0.0003 to 3% by weight. When the particle content exceeds 5% by weight, the transparency of the film may be insufficient.

  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.

  The polyester film in the present invention may contain conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments and the like as necessary in addition to the above-described particles.

  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 it is preferably from 5 to 300 μm, more preferably from the viewpoint of mechanical strength, handling properties and productivity. Is preferably in the range of 10 to 100 μm, and more preferably 12 to 50 μm when used as a pressure-sensitive adhesive separator for polarizing plates or a protective film for pressure-sensitive adhesives for polarizing plates.

  As a film forming method of the film of the present invention, a generally known film forming method can be adopted, and there is no particular limitation. For example, when producing a biaxially stretched polyester film, the polyester raw material described above is first melt-extruded from a die using an extruder, and the molten sheet is 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 or a liquid application adhesion method is preferably employed.

  Next, the obtained 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-stage stretching direction at usually 70 to 170 ° C. and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, a method of obtaining a biaxially oriented film by performing heat treatment at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% is mentioned. 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 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 270 ° C. under tension or 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 a release layer constituting the laminated film in the present invention will be described. Regarding the release layer, it may be provided by in-line coating which treats the film surface during the process of forming the polyester film, or offline coating which is applied outside the system on the 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 a 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 such a method, film formation and mold release layer formation can be performed at the same time, so there is an advantage in manufacturing cost. In addition, in order to perform stretching after coating, the thickness of the mold release layer can be changed depending on the stretch ratio. The thin film coating can be performed more easily than the offline coating. Further, by providing a release layer on the film before stretching, the release layer can be stretched together with the base film, whereby the release 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 release layer is improved, and the release layer and the base film are adhered more firmly. And the migration of the release component to the adhesive layer can be prevented. Furthermore, it can be set as a firm release layer, and the performance and durability of the release layer can be improved. Therefore, as a method for forming the release layer on at least one side of the polyester film, a production method in which a coating solution containing a release component is applied to the polyester film and then stretched in at least one direction is preferable.

  In the present invention, at least one side of the polyester film has a release layer and an adhesive layer in this order, and it is an essential requirement that the release layer contains a long-chain alkyl group-containing compound and a crosslinking agent. is there.

  The release layer in the present invention is preferably used to peel off the adhesive layer from the polyester film when used as, for example, an adhesive for a polarizing plate and its separator, or an adhesive for a protective film for a polarizing plate and its protective film. It is provided to give possible releasability.

  As a result of various studies, the present inventors have used a long-chain alkyl group-containing compound and a crosslinking agent in combination to maintain releasability from the adhesive layer, and after peeling off the polyester film, the adhesiveness of the adhesive layer Found that it is possible to hold.

  The long-chain alkyl group-containing compound contained in the release layer of the laminated film of the present invention is used for improving the release property of the polyester film.

  The long-chain alkyl compound is a compound having a linear or branched alkyl group having usually 6 or more, preferably 8 or more, 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, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary ammonium salts. . 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.

  In the present invention, it is essential to use a long-chain alkyl group-containing compound in order to improve the mold releasability of the film, but a plurality of conventionally known release agents may be used in combination. Examples of conventionally known release agents include waxes, fluorine compounds, and silicone compounds. However, it is desirable that the release layer of the present invention is formed of a release agent of a non-silicone compound from the viewpoint that the adhesiveness of the adhesive layer may be lowered due to migration of the silicone component to the adhesive layer. “Formed with a release agent of a non-silicone compound” means that the silicone compound content of the release layer is preferably 10% by weight or less, more preferably 5% by weight or less, even more preferably 1% by weight or less, and particularly preferably Means 0.5% by weight or less, and most preferably means not intentionally contained. Even if the silicone compound is not actively used, there is a possibility that contaminants derived from foreign substances, etc., and dirt adhering to the film manufacturing process line and apparatus may be mixed.

  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.

  The crosslinking agent used for forming the release layer of the film of the present invention can improve the strength of the release layer, the adhesion to the substrate, and the heat resistance.

  Examples of the crosslinking agent used in the present invention include melamine compounds, isocyanate compounds, oxazoline compounds, epoxy compounds, carbodiimide compounds, and the like. Among these crosslinking agents, it is preferable to use a melamine compound or an isocyanate compound from the viewpoint that the coating film strength is good. Moreover, a melamine compound is preferable from a viewpoint of being excellent in the mold release property of a mold release layer, and an isocyanate type compound is especially preferable from a viewpoint of being excellent in the heat resistance of a mold release layer. Moreover, these crosslinking agents may use 2 or more types together.

  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. Examples of the alkylolation include methylolation, ethylolation, isopropylolation, n-butyroylation, and isobutyrololization. Among these, methylolation is preferable from the viewpoint of reactivity. Moreover, as alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol, etc. are used suitably. From the viewpoint of improving the coating film strength and improving the adhesion between the release layer and the substrate, it is preferably an alkylolated melamine derivative partially etherified, and is an alkylol etherified with methyl alcohol. It is more preferable. Therefore, a more preferable form is a partially etherified melamine having a methylol group and a methoxymethyl group. The etherified alkylol group is preferably 0.5 to 5 equivalents, more preferably 0.7 to 3 equivalents, relative to the non-etherified alkylol group. 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 isocyanate compound is a compound having an isocyanate derivative structure represented by a blocked isocyanate having a structure in which an isocyanate group of an isocyanate compound as a precursor is protected with a blocking agent. Examples of the isocyanate include aliphatic isocyanate compounds, alicyclic isocyanate compounds, and aromatic isocyanate compounds. These isocyanate compounds are more preferably compounds having a plurality of isocyanate groups, that is, polyisocyanate compounds, from the viewpoint that they can be reacted to a higher degree and can improve the heat resistance of the release layer. Further, when an aqueous coating solution is used, it is more preferably a blocked isocyanate.

  Examples of the aliphatic polyisocyanate compound are derived from aliphatic diisocyanates such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-diisocyanatohexane, and lysine diisocyanate. Polyisocyanate compounds, lysine triisocyanate, 4-isocyanatomethyl-1,8-octamethylene diisocyanate, bis (2-isocyanatoethyl) 2-isocyanatoglutarate, or compounds derived from these isocyanate compounds be able to. Of these, hexamethylene diisocyanate is preferred because of its industrial availability.

  Examples of the alicyclic polyisocyanate compound include isophorone diisocyanate (1,3-bis (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, norbornene diisocyanate, hydrogenated xylylene diisocyanate, or these isocyanates. Examples include compounds derived from compounds, etc. Among them, isophorone diisocyanate is preferred from the viewpoint of weather resistance and industrial availability.

  Examples of the aromatic polyisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, or these isocyanate compounds. A compound etc. can be mentioned.

  Among these polyisocyanate compounds, aliphatic polyisocyanate compounds and alicyclic polyisocyanate compounds are preferable because of excellent weather resistance. Furthermore, among aliphatic polyisocyanate compounds, aliphatic polyisocyanate compounds derived from aliphatic diisocyanates are preferred. Among these, hexamethylene diisocyanate is particularly preferable. Moreover, these isocyanate compounds may be used independently and may use 2 or more types together.

  The block polyisocyanate compound can be synthesized by reacting the isocyanate group of the polyisocyanate compound with a blocking agent.

  Examples of the blocking agent include active methylene, oxime, pyrazole, alcohol, alkylphenol, phenol, mercaptan, acid amide, acid imide, imidazole, urea, amine, imine, heavy Examples thereof include a sulfite blocking agent. Among these, an active methylene blocking agent is preferable from the viewpoint that the peeling characteristics after heating are particularly difficult to change. Moreover, these blocking agents may use 2 or more types together.

  Examples of the active methylene-based blocking agent include isobutanoyl acetate, n-propanoyl acetate, n-butanoyl acetate, n-pentanoyl acetate, n-hexanoyl acetate, 2-ethylheptanoyl acetate, malonate, Examples thereof include acetoacetic acid esters and acetylacetone. Among them, isobutanoyl acetate, n-propanoyl acetate, n-butanoyl acetate, n-pentanoyl acetate, n-hexanoyl acetate, 2- Ethylheptanoyl acetate is preferable, more preferably isobutanoyl acetate, n-propanoyl acetate, n-pentanoyl acetate, and still more preferably isobutanoyl acetate. More specifically, examples of isobutanoyl acetate include, for example, methyl isobutanoyl acetate, ethyl isobutanoyl acetate, n-propyl isobutanoyl acetate, isopropyl isobutanoyl acetate, n-butyl isobutanoyl acetate, isobutyl isobutanoyl acetate, t-butyl isobutanoyl acetate, isobutanoyl acetate Examples include n-pentyl, n-hexyl isobutanoyl acetate, 2-ethylhexyl isobutanoyl acetate, phenyl isobutanoyl acetate, and benzyl isobutanoyl acetate. Of these, methyl isobutanoyl acetate and ethyl isobutanoyl acetate are preferred. Examples of n-propanoyl acetate include n-propanoyl methyl acetate, n-propanoyl ethyl acetate, n-propanoyl acetate isopropyl, n-propanoyl acetate n-butyl, n-propanoyl acetate t-butyl and the like. Among these, n-propanoyl methyl acetate and n-propanoyl ethyl acetate are preferable. Examples of n-pentanoyl acetate include n-pentanoyl methyl acetate, n-pentanoyl ethyl acetate, n-pentanoyl acetate isopropyl, n-pentanoyl acetate n-butyl, and n-pentanoyl acetate t-butyl. Among these, n-pentanoyl methyl acetate and n-pentanoyl ethyl acetate are preferable.

  In the active methylene blocked isocyanate compound used in the film of the present invention, the active methylene blocking agent shown above can be used alone or in combination of two or more. As the active methylene-based blocking agent used in combination, dimethyl malonate and diethyl malonate are preferable in that they are excellent in low-temperature curability and excellent in heat resistance of the formed release layer.

  Examples of the oxime blocking agent include formaldehyde oxime, acetoald oxime, acetone oxime, methyl ethyl ketoxime, and cyclohexanone oxime.

  Examples of the pyrazole-based blocking agent include pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like. Examples of the alcohol blocking agent include methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol and the like. It is done.

  Examples of the alkylphenol-based blocking agent include monoalkylphenols such as n-propylphenol, isopropylphenol, n-butylphenol, sec-butylphenol, t-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-octylphenol, and n-nonylphenol. Di-n-propylphenol, diisopropylphenol, isopropylcresol, di-n-butylphenol, di-t-butylphenol, di-sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol, di-n- And dialkylphenols such as nonylphenol.

  Examples of the phenolic blocking agent include phenol, cresol, ethylphenol, styrenated phenol, hydroxybenzoic acid ester, and the like.

  Examples of the mercaptan block agent include butyl mercaptan and dodecyl mercaptan.

  Examples of the acid amide blocking agent include acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam and the like.

  Examples of the acid imide blocking agent include succinimide and maleic imide.

  Examples of the imidazole blocking agent include imidazole and 2-methylimidazole.

  Examples of the urea blocking agent include urea, thiourea, ethylene urea, and the like.

  Examples of amine blocking agents include diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine, and the like. Examples of the imine blocking agent include ethyleneimine and polyethyleneimine.

  The blocked isocyanate compound used in the film of the present invention preferably contains a hydrophilic part in order to enhance the compoundability in water-based paints. As a method for adding a hydrophilic part to the blocked isocyanate compound, for example, a precursor is used. The method of making the isocyanate group of an isocyanate compound and the hydrophilic compound which has active hydrogen react is mentioned.

  Examples of the hydrophilic compound having active hydrogen used in the blocked isocyanate compound used in the film of the present invention include a polyethylene glycol compound, a carboxylic acid-containing compound, a sulfonic acid-containing compound, and an amine-containing compound. These hydrophilic compounds may be used alone or in combination of two or more.

  Examples of the polyethylene glycol compound include monoalkoxy polyethylene glycol, polyethylene glycol, polyoxypropylene polyoxyethylene copolymer diol, polyoxypropylene polyoxyethylene block polymer diol, and the like. Monoalkoxy polyethylene glycols such as ethoxy polyethylene glycol are preferred.

  Examples of the carboxylic acid group-containing compound include monohydroxycarboxylic acid, dihydroxycarboxylic acid, and derivatives thereof. Among the carboxylic acid group-containing compounds, monohydroxycarboxylic acid or dihydroxycarboxylic acid is preferable, and monohydroxycarboxylic acid is more preferable.

  Specific examples of the carboxylic acid-containing compound include, for example, hydroxypivalic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, or polycaprolactone diol or polyether polyol using these as initiators. Derivatives, and salts thereof.

  Examples of the sulfonic acid group-containing compound include aminoethylsulfonic acid, ethylenediamino-propyl-β-ethylsulfonic acid, 1,3-propylenediamine-β-ethylsulfonic acid, N, N-bis (2-hydroxyethyl) -2. -Aminoethanesulfonic acid, and salts thereof.

  Examples of the amine-containing compound include a hydroxyl group-containing amino compound. Specific examples include dimethylethanolamine and diethylethanolamine.

  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 particularly 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). , N-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group) and the like (meth) acrylic acid esters; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, Unsaturated carboxylic acids such as styrene 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, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.) Vinyl esters such as vinyl and 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 and vinylidene chloride; Styrene , Α-methylstyrene, α, β-unsaturated aromatic monomers, and the like, and one or more of these monomers can be used.

  The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include condensates of epichlorohydrin with ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A and the like hydroxyl groups and amino groups, There are polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like.

  Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane. Examples of the polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, poly Examples of tetramethylene glycol diglycidyl ether and monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N′-tetraglycidyl-m-xylyl. Examples include range amine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

  In addition, the crosslinking agent used for this invention is used by the design which makes it react in a drying process or a film forming process, and improves the performance of a mold release layer. It can be inferred that unreacted products of these crosslinking agents, compounds after the reaction, or mixtures thereof exist in the completed release layer.

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

  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, a polyester resin and a urethane resin are preferable, and a polyester resin is more preferable in that the releasability can be easily controlled.

  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 polycarbonate 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 polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

  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, quaternary ammonium salt, and the like, and a carboxyl group is preferable. 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 release layer, as well as excellent stability in a liquid state before coating.

  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 with a base material 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.

  As a ratio with respect to all the non-volatile components of the release layer constituting the laminated film in the present invention, the long chain alkyl group-containing compound is usually in the range of 5 to 97% by weight, preferably in the range of 8 to 95% by weight, and more preferably 10%. It is in the range of ~ 90% by weight. When the amount is less than 5% by weight, sufficient release performance may not be obtained. When the amount is more than 97% by weight, the strength of the release layer may be insufficient because other components are small.

  When a melamine compound is used as the cross-linking agent, the ratio of the long-chain alkyl group-containing compound is preferably in the range of 30 to 95% by weight, more preferably in the range of 50 to 90% by weight, as a ratio to the total nonvolatile components of the release layer. A range of 60 to 85% by weight is particularly preferred.

  When an isocyanate compound is used as the cross-linking agent, the ratio of the long-chain alkyl group-containing compound is preferably in the range of 10 to 95% by weight, more preferably in the range of 20 to 90% by weight, as a ratio to the total nonvolatile components of the release layer. A range of 30 to 85% by weight is particularly preferable.

  As a ratio with respect to all the non-volatile components of the release layer constituting the laminated film in the present invention, the crosslinking agent is usually in the range of 3 to 95% by weight, preferably in the range of 5 to 90% by weight, and more preferably in the range of 10 to 80% by weight. Range. When it is out of the above range, the releasability may be insufficient, and the heat resistance of the release layer may be inferior.

  When a melamine compound is used as the crosslinking agent, the ratio of the melamine compound to the total nonvolatile components of the release layer is preferably 5 to 70% by weight, more preferably 10 to 60% by weight, and 15 to 40% by weight. % Range is particularly preferred.

  When an isocyanate compound is used as the cross-linking agent, the isocyanate compound is preferably in the range of 5 to 90% by weight, more preferably in the range of 10 to 80% by weight, as a ratio to the total nonvolatile components of the release layer. A range of 70% by weight is particularly preferred.

  The peeling force of the release layer of the present invention depends on the type of the pressure-sensitive adhesive, but is preferably 1000 mN / cm or less, more preferably 600 mN / cm or less, and still more preferably 300 mN / cm or less, for example, for an acrylic pressure-sensitive adhesive. It is. The lower limit of the peeling force is usually 10 mN / cm.

  The peel strength of the release layer of the present invention after the heat treatment on the acrylic adhesive tape is preferably 2500 mN / cm or less, more preferably 1900 mN / cm or less, more preferably, although it depends on the value of the peel force before heating. It is 1500 mN / cm or less, and particularly preferably 1300 mN / cm or less. By setting it within the above range, it is possible to peel the adhesive layer well even when heat treatment is applied. Moreover, the minimum of the peeling force after heat processing is 10 mN / cm normally.

  The release layer in the present invention is characterized in that it is laminated on at least one side of the polyester film, but it may be laminated on both sides, and in this case, each side may have the same composition or different. In addition, the laminated film in the present invention has a structure in which a release layer and an adhesive layer are laminated in this order on at least one side of the polyester film, but when the release layer is laminated on both sides of the polyester film, the adhesive is also separated on both sides. It may be provided on the mold layer or only on one side. When laminating on both sides, the composition of the adhesive layer may be the same or different.

  Moreover, you may provide a functional layer with a mold release layer in the other surface of a polyester film. Although a functional layer is not specifically limited, When using a polyester film as a separator, it is preferable that it is a layer containing an antistatic agent in order to suppress the static electricity which generate | occur | produces when peeling a film. Moreover, as a method of providing the functional layer, the same technique as that of the release layer can be used.

  Antistatic agents are ion-conductive polymer compounds such as ammonium group-containing compounds, polyether compounds, sulfonic acid compounds, and betaine compounds, and π electrons such as polyacetylene, polyphenylene, polyaniline, polypyrrole, polyisothianaphthene, and polythiophene. Examples thereof include conjugated polymer compounds. These are used to impart antistatic properties to the film. Among these, an ion conductive polymer compound is preferable, and an ammonium group-containing compound is particularly preferable. A functional layer formed from a coating liquid containing a π-conjugated conductive polymer such as polythiophene or polyaniline is generally strongly colored and may not be suitable for optical applications requiring transparency. In addition, since π-conjugated conductive polymer paints are generally more expensive than ion conductive paints, ion conductive antistatic agents are preferably used from the viewpoint of manufacturing cost.

  The ammonium group-containing compound refers to a compound having an ammonium group in the molecule, and is preferably a polymer compound having an ammonium group. For example, a polymer containing a monomer having an ammonium group and an unsaturated double bond as components can be used.

  Specific examples of such a polymer include a polymer having a constituent represented by the following formula (1) or the following formula (2) as a repeating unit. These homopolymers and copolymers, and other plural components may be copolymerized. From the viewpoint of improving the compatibility with other materials and the transparency of the resulting coating film, a polymer having a constituent represented by the following formula (1) as a repeating unit is preferred. Moreover, the polymer which has the structural element shown by following formula (2) as a repeating unit from the viewpoint of the high antistatic performance obtained and heat resistance is preferable.

In the above formula (1), R ² is —O— or —NH—, R ³ is an alkylene group, or other structure capable of forming the structure of formula (1), R ¹ , R ⁴ , R ⁵ , R ⁶ Are each 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, hydroxy group, amide group, ester group, alkoxy group, phenoxy group, naphthoxy group, thioalkoxy group, thiophenoxy group, cycloalkyl group, trialkylammonium alkyl group, cyano group, halogen, etc. is there.

In said formula (2), R < ¹ >, R < ² > is respectively independently a hydrogen atom, 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, amide group, ester group, alkoxy group, phenoxy group, naphthoxy group, thioalkoxy group, thiophenoxy group, cycloalkyl group, trialkylammonium alkyl group, cyano group, halogen, etc. is there. R ¹ and R ² may be chemically bonded. For example, — (CH ₂ ) _m — (m is an integer of 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.

  In the case of a polymer having the structural element represented by the above formula (1) as a repeating unit, the viewpoint of improving the compatibility with other materials and improving the transparency of the resulting coating film, and further improving the releasability From the viewpoint of, it is preferable to copolymerize with other repeating units. Other repeating units include, for example, alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate, and alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Can be mentioned.

  In the case of a polymer having the constituent represented by the above formula (2) as a repeating unit, it is preferably copolymerized with another repeating unit from the viewpoint of suppressing a decrease in releasability. Other repeating units include, for example, alkyl acrylates, alkyl methacrylates, and acrylamides such as n-methylol acrylamide.

  Further, from the viewpoint of further improving the antistatic performance, a homopolymer having the constituent represented by the above formula (2) as a repeating unit is preferable.

X ⁻ in the above formulas (1) and (2) can be appropriately selected within a range not impairing the gist of the present invention. Examples include halogen ions, sulfonates, phosphates, nitrates, alkyl sulfonates, and carboxylates.

The polymer having the component represented by the above formula (1) is preferable because of the excellent transparency of the obtained functional layer. However, in the coating stretching method, heat resistance may be inferior, and when used in the coating stretching method, X ⁻ is preferably not a halogen.

  A compound represented by the above formula (2) or other ammonium base in the polymer skeleton is excellent in heat resistance and is preferable.

  The number average molecular weight of the ammonium group-containing compound is 1000 to 500000, preferably 2000 to 350,000, and more preferably 5000 to 200000. When the molecular weight is less than 1000, the strength of the coating film may be weak or the heat resistance 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.

  In forming the functional layer, various polymers and crosslinking agents can be used in combination in order to improve the coating appearance, transparency, and substrate adhesion. As the various polymers and crosslinking agents, the various materials described in the release layer of the present invention can be used. Examples of the polymers include polyester resins, acrylic resins, urethane resins, polyvinyls (polyvinyl alcohol, vinyl chloride). Vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches and the like. Examples of the crosslinking agent include melamine compounds, isocyanate compounds, oxazoline compounds, epoxy compounds, carbodiimide compounds, and the like. Among these, it is preferable to use an acrylic resin as the polymer. Moreover, it is preferable to use melamine as a crosslinking agent. Two or more of these may be used in combination.

When an antistatic layer is provided as a functional layer, depending on the application used, the surface resistance is preferably 5 × 10 ¹² Ω or less, more preferably 1 × 10 ¹¹ Ω or less, and even more preferably 5 × 10 ¹⁰ Ω or less. It is.

  As long as the gist of the present invention is not impaired, particles can be used in combination with the formation of the release layer and the functional layer of the film of the present invention for the purpose of improving the blocking property and slipping property of the release layer.

  Further, as long as it does not impair the gist of the present invention, the release layer and the functional layer are formed as necessary, such as an antifoaming agent, a coating property improving agent, a thickener, an organic lubricant, an antistatic agent, and an ultraviolet absorber. In addition, an antioxidant, a foaming agent, a dye, a pigment, and the like can be used in combination.

  Analysis of components in the release layer and the functional layer can be performed, for example, by analysis of TOF-SIMS, ESCA, fluorescent X-rays, and the like.

  When a release layer or functional layer is provided by in-line coating, a coating solution prepared by adjusting the above-mentioned series of compounds as an aqueous solution or water dispersion with a solid content concentration of about 0.1 to 50% by weight as a guide is applied to the polyester film. It is preferable to produce a laminated polyester film in the manner of applying to the substrate. 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 film in the present invention, the thickness of the release layer provided on the polyester film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm, and still more preferably 0.01 to 0.2 μm. Range. When the film thickness exceeds 1 μm, the appearance of the coating film may be deteriorated and the coating film may be insufficiently cured. When the film thickness is less than 0.001 μm, sufficient releasability may not be obtained. .

  Regarding the laminated film in the present invention, when a functional layer is provided on the other surface of the polyester film, the film thickness is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm, and still more preferably 0.00. It is in the range of 01 to 0.2 μm. If the film thickness exceeds 1 μm, the appearance of the coating film may be deteriorated and the coating film may be insufficiently cured. If the film thickness is less than 0.001 μm, sufficient antistatic properties may not be obtained. .

  Examples of the method for forming the release 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, Conventionally known coating methods such as impregnation coating, kiss coating, spray coating, calendar coating, and extrusion coating can be used.

  In the present invention, regarding the drying and curing conditions when forming the release layer on the polyester film, for example, when the release layer is provided by off-line coating, usually at 80 to 200 ° C. for 3 to 40 seconds, preferably 100. The heat treatment is preferably performed at ˜180 ° C. for 3 to 40 seconds as a guide.

  On the other hand, when providing a release layer 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.

  When the adhesive layer in the present invention is used as, for example, a protective film cover film for a polarizing plate or an adhesive film for bonding a polarizing plate and an image display device, an optical member such as a polyester film and a polarizing plate is bonded, Moreover, after peeling a polyester film, it is provided in order to provide the adhesiveness which can be used conveniently for the purpose of bonding together with another optical member.

  The pressure-sensitive adhesive layer contains a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition can be used without particular limitation as long as it can impart adhesiveness, and examples thereof include acrylic pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives. Among these, an acrylic pressure-sensitive adhesive is preferable from the viewpoint of easy adjustment of the adhesive properties and excellent transparency. Moreover, as a formation method of an adhesive, a thermosetting type, an active energy ray hardening type, a hot-melt type etc. are mentioned, for example.

  The acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing an acrylic resin which is a polymer made of a polymerizable monomer containing an acrylic or methacrylic monomer. These may be either a homopolymer or a copolymer, and a copolymer with a polymerizable monomer other than an acrylic or methacrylic monomer. The acrylic and methacrylic polymerizable monomers and other polymerizable monomers are not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, and n-propyl (meth). Acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl ( (Meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylic acid ester such as tetradecyl (meth) acrylate, 2-hydroxy ester (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) Hydroxyl group-containing monomers such as acrylate, 2-hydroxypropylene glycol (meth) acrylate, carboxyl group-containing monomers such as (meth) acrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid and maleic anhydride, and Their salts, nitrogen-containing compounds such as (meth) acrylamide, diacetone acrylamide, N-methylol acrylamide, N-vinyl pyrrolidone or N-vinyl caprolactam, vinyl chloride and vinylidene chloride Vinyl halides such, like various conjugated dienes such as butadiene. Among these, the case where it consists of at least 1 sort (meth) acrylic acid ester as a polymerizable monomer is preferable. Further, it is preferable that a hydroxy group-containing monomer or a carboxyl group-containing monomer having a hydroxy group or a carboxyl group is copolymerized.

  The weight average molecular weight of the acrylic resin is preferably 10,000 to 5,000,000, more preferably 100,000 to 4,000,000. When the weight average molecular weight is less than 10,000, the cohesive force of the obtained adhesive layer is small, so that breakage may occur in the adhesive layer. On the other hand, if it exceeds 5,000,000, the fluidity of the resin is lowered, so that wetting to an optical member such as a polarizing plate may be insufficient.

  In addition, the glass transition temperature of the acrylic resin is preferably in the range of −100 to 0 ° C., and in the range of −80 to −20 ° C. from the viewpoint that the wettability and adhesion to the adherend can be appropriately provided. More preferable

  The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the laminated film of the present invention further contains a solvent, a crosslinking agent, a tackifier, a filler, a colorant, an antioxidant, an antistatic agent, an ultraviolet absorber, etc. as necessary. You may go out.

  Although it does not specifically limit as a crosslinking agent used for an acrylic adhesive, For example, a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, an aziridine compound, a metal chelate Compounds, metal alkoxides, metal salts and the like are used.

  Regarding the laminated film in the present invention, the thickness of the pressure-sensitive adhesive layer is preferably 1 to 500 μm, more preferably 5 to 200 μm, and still more preferably 10 to 100 μm. When the thickness is less than 1 μm, the tackiness may be insufficient, and when it exceeds 500 μm, the tackiness may not be stably obtained.

  The laminated film of the present invention can be used for bonding the adhesive layer to an optical member such as a polarizing plate. As an example of its use, a polyester film and a release layer are used as a separator, a separator is bonded to a polarizing plate via an adhesive layer, and after the separator is peeled off, the polarizing plate is an optical member via an adhesive layer. Or an optical member or an image display device bonded to an image display device, or a protective film in which a separator is bonded to a protective film using an adhesive layer, and the protective film is polarized through the adhesive layer after peeling off the separator. Examples thereof include an optical member bonded to an optical member such as a plate.

  For example, a polarizing plate having a transparent protective film on one side or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. Examples thereof include polyene-based oriented films such as those obtained by adsorbing a functional substance and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, from the viewpoint of having a high degree of polarization, a polarizer made of a polyvinyl alcohol film containing iodine is preferably used.

  Polyvinyl alcohol or a derivative thereof is used as a material for the polyvinyl alcohol film applied to the polarizer. Derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal, and the like, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters and acrylamide. Things. Polyvinyl alcohol having a polymerization degree of about 1000 to 10000 and a saponification degree of about 80 to 100 mol% is generally used. The thickness of these polarizers is not particularly limited, but is preferably 1 to 1000 μm, more preferably 10 to 200 μm, taking into consideration the strength as a film and the homogeneity during stretching.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride and the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be performed with dyeing after iodine. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like is used. For example, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) And polymers based on polycarbonate and polycarbonate. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfones Polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or Examples of the polymer that forms the transparent protective film include blends of the polymer.

  The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, and silicone. Among these, cellulose-based polymers such as triacetyl cellulose are preferable from the viewpoint of polarization characteristics and durability, and triacetyl cellulose film is particularly preferable.

  When providing a protective film on both sides of the polarizer, a protective film made of the same polymer material may be used on the front and back, or a protective film made of a different polymer material or the like may be used. The polarizer and the protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include polyvinyl alcohol-based adhesive, isocyanate-based adhesive, gelatin-based adhesive, vinyl-based latex, water-based polyurethane, water-based polyester, and the like.

The thickness of the protective film can be appropriately determined, but in general, from the viewpoint of workability such as strength and handleability, thin layer properties, etc., 1 to 500 μm is preferable, 1 to 300 μm is more preferable, and 5 to 200 μm is more preferable. preferable.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a treatment for the purpose of hard coat layer, antireflection treatment, antisticking, or diffusion or antiglare. Further, these antireflection layer, antisticking layer, diffusion layer, antiglare layer and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  Moreover, as an optical member to be bonded to an optical member such as a polarizing plate using the laminated film of the present invention, for example, a reflecting plate, a semi-transmissive plate, a retardation plate (including wavelength plates such as 1/2 and 1/4) And a member of an image display device such as a liquid crystal cell and an optical layer that may be used for forming a liquid crystal display device such as a viewing angle compensation film and a brightness enhancement film. These optical layers can be used alone as the optical member of the present invention, and can be laminated on the polarizing plate for practical use to use one layer or two or more layers.

  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) Measurement of average particle diameter (d50) The average particle diameter d50 is the average particle diameter of 50% in the equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type) manufactured by Shimadzu Corporation. It was.

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

(4) Evaluation of release force of release layer Adhesive tape (Nitto Denko “No. 31B” base material thickness 25 μm) was applied to the surface of the release layer of the polyester film provided with the release layer with a 2 kg rubber roller. The peel force after reciprocating was measured after standing at room temperature for 1 hour. For the peeling force, “Ezgraph” manufactured by Shimadzu Corporation was used, and 180 ° peeling was performed under the condition of a tensile speed of 300 mm / min.

(5) Evaluation of peel strength after heating of release film Adhesive tape (Nitto Denko “No. 31B” base material thickness 25 μm) is applied to a 2 kg rubber roller on the release layer surface of a polyester film provided with a release layer. After one reciprocating pressure bonding, it was heated in an oven at 100 ° C. for 1 hour. Thereafter, the peel force after standing at room temperature for 1 hour was measured. For the peeling force, “Ezgraph” manufactured by Shimadzu Corporation was used, and 180 ° peeling was performed under the condition of a tensile speed of 300 mm / min.

(6) Transferability of adhesive layer An adhesive layer was laminated on the release layer, and the adhesive layer surface was bonded to the polarizing plate. After 24 hours in a 23 ° C. environment, the polyester film and the polarizing plate were peeled off in the 180 ° direction to examine whether the adhesive layer was transferred to the polarizing plate. When the pressure-sensitive adhesive layer was transferred to the polarizing plate, it was marked with ◯, and when the pressure-sensitive adhesive layer remained on the polyester film side, it was marked with x.

(7) Evaluation Method of Surface Resistance Value Using a high resistance measuring instrument: HP4339B and measuring electrode: HP16008B manufactured by Japan Hewlett-Packard Co., Ltd., functioning after conditioning the sample for 30 minutes in a measurement atmosphere of 23 ° C. and 50% RH The surface resistance value of the layer surface was measured.

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (A)>
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, 30 ppm of ethyl acid phosphate with respect to the resulting polyester, and 100 ppm of magnesium acetate tetrahydrate with respect to the resulting polyester as the catalyst at 260 ° C. in a nitrogen atmosphere at 260 ° C. The reaction was allowed to proceed. Subsequently, 50 ppm of tetrabutyl titanate was added to the resulting polyester, the temperature was raised to 280 ° C. over 2 hours and 30 minutes, the pressure was reduced to 0.3 kPa in absolute pressure, and melt polycondensation was further carried out for 80 minutes. A polyester (A) having 0.63 and an amount of diethylene glycol of 2 mol% was obtained.

<Method for producing polyester (B)>
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, and magnesium acetate tetrahydrate as a catalyst were subjected to an esterification reaction at 225 ° C. in a nitrogen atmosphere at 900 ppm with respect to the produced polyester. Subsequently, 3500 ppm of orthophosphoric acid was added to the produced polyester, and 70 ppm of germanium dioxide was added to the produced polyester. The temperature was raised to 280 ° C. over 2 hours and 30 minutes, and the pressure was reduced to an absolute pressure of 0.4 kPa. After 85 minutes of melt polycondensation, polyester (B) having an intrinsic viscosity of 0.64 and a diethylene glycol amount of 2 mol% was obtained.

<Method for producing polyester (C)>
In the production method of polyester (A), polyester (C) is obtained using the same method as the production method of polyester (A), except that 0.3 part by weight of silica particles having an average particle diameter of 2 μm is added before melt polymerization. It was.

Examples of compounds constituting the release layer and the functional layer are as follows.
・ Long chain alkyl group-containing compound: (IA)
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.

・ Melamine compounds: (IIA)
Partially etherified melamine in which the ratio of methylol group to methoxy group is 1: 2.2
Active methylene block polyisocyanate: (IIB)
1000 parts of block polyisocyanate hexamethylene diisocyanate synthesized by the following method was stirred at 60 ° C., and 0.1 part of tetramethylammonium caprylate 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.

・ Polyester resin: (IIIA)
Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4-butanediol / diethylene glycol = 56/40/4 // 70/20/10 (mol%)
Acrylic resin: (IIIB) Aqueous dispersion of acrylic resin polymerized with the following composition: ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (% by weight) Emulsion polymer (emulsifier: anionic surfactant)
・ Urethane resin (IIIC)
Aqueous dispersion of polyester urethane resin formed from isophorone diisocyanate / terephthalic acid / isophthalic acid / ethylene glycol / diethylene glycol / dimethylolpropanoic acid = 12/19/18/21/25/5 (mol%)

・ Antistatic agent: (IV)
A polymer compound having a number average molecular weight of 30000, obtained by copolymerizing a structural unit of the following formula 3-1 and a structural unit of the following formula 3-2 in a weight ratio of 95/5.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is prepared as follows.
A pressure-sensitive adhesive composition in which 0.5 part of an isocyanate crosslinking agent is blended with 100 parts by weight of an acrylic copolymer of butyl acrylate / acrylic acid / vinyl acetate = 100/2/5 (% by weight).

The polarizing plate was created by the following method.
A polarizer protective film made of a triacetyl cellulose film having a thickness of 40 μm was bonded to both sides of a polarizer having a thickness of 30 μm prepared by dyeing a polyvinyl alcohol film with iodine, and then prepared using a polyvinyl alcohol-based adhesive. .

Example 1:
A mixed raw material in which polyesters (A), (B), and (C) were mixed in proportions of 91%, 3%, and 6%, respectively, was used as a raw material for the outermost layer (surface layer), and polyesters (A) and (B) were each 97 %, 3% of the mixed raw material is used as an intermediate layer raw material, each is supplied to two extruders, melted at 285 ° C., and then on a cooling roll set at 40 ° C. Coextruded and cooled and solidified in a layer structure of layers (surface layer / intermediate layer / surface layer = 1: 8: 1 discharge amount) to obtain an unstretched sheet.
Next, the film was stretched 3.4 times in the machine direction at a film temperature of 85 ° C. using the roll peripheral speed difference, and then the coating liquid A1 shown in Table 1 below was applied to one side of the longitudinally stretched film. The coating solution B1 was applied to the film, guided to a tenter, stretched 4.0 times at 120 ° C. in the transverse direction, heat treated at 235 ° C., relaxed 2% in the transverse direction, and the thickness of the coating layer on one side ( After drying, a polyester film having a thickness of 38 μm having a release layer having a thickness of 0.03 μm and a functional layer having a coating layer thickness (after drying) of 0.03 μm on the other surface was obtained. When the release layer of the obtained polyester film was evaluated, the release property after heating was good, and the functional layer was also a film having excellent surface resistance.

  An adhesive layer formed with a thickness of 25 μm was laminated on the surface of the release layer of this polyester film to obtain a laminated film with an adhesive. By laminating the obtained laminated film to the polarizing plate, it is possible to create a polarizing plate with a separator using a polyester film as a separator, and the adhesive layer does not remain on the surface of the release layer when the separator is peeled off. It was a film capable of transferring the adhesive layer to the polarizing plate. The properties of this film are shown in Table 2 below.

Examples 2-25:
In Example 1, except having changed the composition of a mold release layer and a functional layer into the coating agent composition shown in Table 1, it manufactured like Example 1 and obtained the laminated | multilayer film. As shown in Table 2, the finished polyester film had good release properties of the release layer, transferability of the adhesive layer, and surface resistance of the functional layer.

Comparative Example 1:
In Example 1, it manufactured like Example 1 except not providing a mold release layer and a functional layer, and obtained the laminated film. When the completed laminated film was evaluated, it was as shown in Table 2. As a result, the release layer was inferior in releasability, the adhesive layer could not be transferred, and the surface resistance value was also inferior.

Comparative Examples 2-5:
In Example 1, it manufactured like Example 1 except having changed the coating agent composition of a mold release layer and a functional layer into the coating agent composition shown in Table 1, and obtained the polyester film. The completed laminated film was evaluated and as shown in Table 2, the release layer was poorly releasable, the adhesive layer was not transferable, and the functional layer was also inferior in surface resistance. It was.

  The release film of the present invention is a laminated film using a release film that does not use a silicone composition. For example, an adhesive for a polarizing plate and its separator, and an adhesive for a protective film for a polarizing plate and its protective film. As a laminated film preferably used, it can be suitably used.

Claims (1)

A laminated film in which a release layer and an adhesive layer are laminated in this order on at least one surface of a polyester film, and the release layer contains a long-chain alkyl group-containing compound and a crosslinking agent.