JP7003915B2 - Release film - Google Patents

Description

The present invention relates to a release film.

Conventionally, a release film based on a polyester film is used for various purposes (capacitive touch panel, LCD polarizing plate, retardation plate, PDP component, organic EL component, etc.) to be bonded via an adhesive layer. It is used for various display components, various optical applications, etc.).

The base material-less double-sided adhesive sheet is composed of a laminated body structure in which a light release film having a relatively low peeling force and a heavy release film having a relatively high peeling force are laminated on both sides of the adhesive layer. After removal, it is a double-sided pressure-sensitive adhesive sheet that has only a pressure-sensitive adhesive layer without a supporting base material.

As a method of using the base material-less double-sided adhesive sheet, the light release film is first peeled off, one surface of the exposed adhesive layer is adhered to the object surface of the other party to be bonded, and then the heavy release film is further peeled off. An example is a processing step in which the other surface of the exposed adhesive layer is adhered to a different object surface, whereby the objects are surface-bonded.

In recent years, the base-less double-sided adhesive sheet has attracted attention for its good workability, and its applications are expanding, and it is also used for various optical application members, for example, mobile phones and the like. In particular, the capacitive touch panel is in a situation where its use as an information terminal is rapidly expanding by multi-touch operation in which the screen is operated with two fingers. Since the capacitance type touch panel tends to have a thicker printing step than the resistance film type, it has been proposed to thicken the adhesive layer to eliminate the printing step. If the adhesive layer is thickened, when the release film is peeled off, a part of the adhesive layer adheres to the release film, or bubbles are mixed in the adhesive layer of the portion transferred to the release film. There was a case. Therefore, when the base material-less double-sided adhesive sheet is used for optical applications, not only the base material-less double-sided adhesive sheet but also the release film to be combined is stricter than before, and the release film of higher quality is obtained. The situation is needed.

In the use of a base-less double-sided adhesive sheet, when the light release type film is peeled off from the adhesive layer, the peeling force of the light release type film is high, and there is a problem that the light release type film cannot be peeled off well from the adhesive.

As a solution to such a problem, for example, Patent Documents 1 to 3 propose to reduce the peeling speed of the release layer to a certain level or less. However, the release films described in Patent Documents 1 to 3 have a problem that light peeling is insufficient and cannot be dealt with at all.

In addition, when using a release film, peeling charge may occur when peeling from the adhesive layer, and as a result, defects such as product defects due to adhesion or entrainment of foreign matter when manufacturing the member may occur. May occur. Therefore, antistatic measures by equipment in the manufacturing process are not always sufficient, and antistatic treatment from the release film itself is strongly desired.

As a solution to such a problem, for example, Patent Document 4 and Patent Document 5 propose an antistatic layer containing a π-electron conjugated conductive polymer. In the antistatic film described in the document, the antistatic property is good, but when the release layer is provided on the antistatic layer, the adhesion between the release layer and the antistatic layer may not always be sufficient. be.

Japanese Unexamined Patent Publication No. 2012-2508 Japanese Unexamined Patent Publication No. 2012-179888 JP-A-2015-142999 Japanese Patent Application Laid-Open No. 2012-183811 Japanese Unexamined Patent Publication No. 2012-993

The present invention has been made in view of the above circumstances, and the first solution is that the mold release property from the adhesive is good regardless of the peeling speed at the time of use, and the adhesive is transferred to the member. The purpose is to provide a release film having less property.
The second solution of the present invention is that the mold release property from the pressure-sensitive adhesive is good, the transferability of the pressure-sensitive adhesive to a member is small, and the mold release property is good in antistatic property, regardless of the peeling speed at the time of use. To provide the film.

As a result of diligent studies in view of the above circumstances, the present inventor has found that the polyester film having a specific configuration can easily solve the above problems, and has completed the present invention.

That is, the technical problem of the present invention can be achieved by the present invention as follows.

(1) The present invention comprises a first polydimethylsiloxane having a weight average molecular weight of 500 or more and 30,000 or less on at least one side of a polyester film and having at least one alkenyl group in one molecule, and a weight average molecular weight. A silicone-based mold release layer comprising a mold release agent composition containing 150 or more and 10000 or less, a second polydimethylsiloxane having at least one hydrosilyl group in one molecule, and a platinum-based catalyst. In the release agent composition, the content of the first polydimethylsiloxane is 40 to 80% by weight, and the content of the second polydimethylsiloxane is 20 to 60% by weight. Moreover, it is a release film characterized in that the total content of each component in the release agent composition is 100% by weight (first invention).

(2) The present invention is a release film in which a coating layer and a release layer are sequentially provided on at least one side of a polyester film, and the coating layer comprises a conductive compound (A) and a binder polymer (B). The release layer contains the first polydimethylsiloxane having a weight average molecular weight of 500 or more and 30,000 or less and having at least one alkenyl group in one molecule, and a weight average molecular weight of 150 or more and 10,000 or less. It is a silicone-based release layer composed of a second polydimethylsiloxane having at least one hydrosilyl group in one molecule and a release agent composition containing a platinum-based catalyst, and the release agent composition . In the product, the content of the first polydimethylsiloxane is 40 to 80% by weight, the content of the second polydimethylsiloxane is 20 to 60% by weight, and the release agent composition has a content of 20 to 60% by weight. It is a polyester film characterized in that the total content of each component is 100% by weight (second invention).

Further, in the present invention, it is preferable that the peeling force between the silicone-based mold release layer surface and the tessa7475 adhesive tape manufactured by tessa is 9 g / 25 mm or less at a peeling speed of 300 mm / min.

According to the present invention, the above-mentioned problems can be solved.
The release film of the present invention is, for example, a substrateless double-sided adhesive sheet for touch panel manufacturing, a polarizing plate used for a liquid crystal display (LCD) for manufacturing a capacitive touch panel, etc. Suitable for manufacturing various display components such as for manufacturing plasma display panel components, organic electroluminescence components, and for protecting various pressure-sensitive adhesive layers.

The first invention of the present application has a layer structure of a polyester film / silicone-based release layer, and the second invention of the present application has a layer structure of a polyester film / coating layer / silicone-based release layer. Hereinafter, the polyester film, the coating layer, and the silicone-based mold release layer will be described in this order.

[Polyester film]
When the release film is used for adhesive protection, a part of the adhesive layer may adhere to the release film at the time of peeling. When the adhesive adheres to the release film, the surface shape of the adhesive layer becomes rough, which may adversely affect the adhesion to other members such as optical members. When the base material of the release film is paper, the polyester film is used in the present invention because not only the adhesive adheres but also the transferability is insufficient at the time of peeling.
The polyester film referred to in the present invention is a film obtained by stretching a sheet melt-extruded from an extrusion base according to a so-called extrusion method.

The polyester constituting the above film refers to a polymer containing an ester group obtained from a dicarboxylic acid and a diol or from a hydroxycarboxylic acid by polycondensation. The dicarboxylic acid includes terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like, and the diol includes ethylene glycol and 1,4-butane. Examples of the hydroxycarboxylic acid include diol, diethylene glycol, triethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, polyethylene glycol and the like, and examples of the hydroxycarboxylic acid include p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. be able to. Typical examples of such polymers include polyethylene terephthalate, polyethylene-2, 6-naphthalate and the like.

Particles are preferably blended in the film of the present invention mainly for the purpose of imparting slipperiness and preventing scratches in each step. The type of particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Particles of magnesium, kaolin, aluminum oxide, titanium oxide and the like can be mentioned. Further, heat-resistant organic particles as described in JP-A-59-5216, JP-A-59-217755, etc. may be used. Examples of other heat-resistant organic particles include thermosetting urea resin, thermosetting phenol resin, thermosetting epoxy resin, benzoguanamine resin and the like. Further, during the polyester manufacturing process, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can also be used.

On the other hand, the shape of the particles to be used is not particularly limited, and any of spherical, lumpy, rod-shaped, flat-shaped and the like may be used. Further, the hardness, specific gravity, color and the like are not particularly limited. Two or more kinds of these series of particles may be used in combination, if necessary.

The average particle size of the particles used is usually in the range of 0.01 to 3 μm, preferably 0.1 to 2 μm. If the average particle size is less than 0.01 μm, it may not be possible to sufficiently impart slipperiness. On the other hand, if it exceeds 3 μm, the transparency may be lowered due to the agglomerates of the particles when the film is formed, and the film is liable to be broken, which causes a problem in terms of productivity. There is.

Further, the particle content in the polyester is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. If the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient, while if it is added in excess of 5% by weight, the transparency of the film is insufficient. In some cases.

The method of adding the 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 of producing the polyester constituting each layer, but it is preferably added after the esterification or transesterification reaction is completed.

Further, a method of blending a slurry of particles dispersed in ethylene glycol or water with a polyester raw material using a kneaded extruder with a vent, or a method of blending dried particles with a polyester raw material using a kneading extruder. It is done by the method.

In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments and the like can be added to the polyester film in the present invention, if 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 in the range of 10 to 350 μm, preferably 15 to 100 μm.

Next, a production example of the polyester film in the present invention will be specifically described, but the present invention is not limited to the following production examples.
First, using the polyester raw material described above, the molten sheet extruded from the die 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 the electrostatic application adhesion method and / or the liquid coating adhesion method is preferably adopted.
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 90 to 140 ° C., preferably 95 to 120 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Then, it is stretched in a direction orthogonal to the stretching direction of the first stage, in which case the stretching temperature is usually 90 to 170 ° C. and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. be.
Then, the heat treatment is subsequently performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film.
In the above stretching, a method of performing one-way stretching in two or more steps can also be adopted. In that case, it is preferable to finally set the draw ratios in the two directions within the above ranges.

Further, for the production of the polyester film of the present invention, a simultaneous biaxial stretching method can also be adopted. The simultaneous biaxial stretching method is a method of simultaneously stretching and orienting the unstretched sheet in the mechanical direction and the width direction in a state where the temperature is controlled at 90 to 140 ° C., preferably 80 to 110 ° C., and the stretching ratio is Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in area magnification. Then, the heat treatment is subsequently performed at a temperature of 170 to 250 ° C. under tension or relaxation within 30% to obtain a stretch-oriented film. As for the simultaneous biaxial stretching device that employs the above-mentioned stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be adopted.

Further, a so-called coating and stretching method (in-line coating), which treats the film surface during the stretching step of the polyester film described above, can be applied. When the coating layer is provided on the polyester film by the coating and stretching method, the coating can be applied at the same time as stretching, and the thickness of the coating layer can be reduced according to the draw ratio, so that a film suitable as a polyester film can be produced. can.

[Coating layer]
The coating layer constituting the release film of the present invention will be described.
It is an essential requirement that the coating layer contains the conductive compound (A) and the binder polymer (B).

(Conductive compound (A))
It is important that the coating layer constituting the release film of the present invention contains the conductive compound (A) in order to improve the antistatic property and the oligomer precipitation prevention property. As the conductive compound (A), a polymer obtained by singly or copolymerizing thiophene or a thiophene derivative is preferable, and in particular, a compound composed of thiophene or a thiophene derivative is doped with another anionic compound or , A compound having an anionic group in the compound and self-doped is suitable because it exhibits excellent conductivity. Examples of the compound (A) include those obtained by polymerizing the following compounds of Chemical formula 1 or Chemical formula 2 in the presence of polyanions.

（Ｒ^１，Ｒ^２はそれぞれ独立に、水素元素、炭素数１～１２の脂肪族炭化水素基、脂環族炭化水素基、もしくは芳香族炭化水素基をあらわし、例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、シクロヘキシレン基、ベンゼン基などである。）

(R ¹ and R ² independently represent a hydrogen element, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, for example, a methyl group, an ethyl group, and the like. Propyl group, isopropyl group, butyl group, cyclohexylene group, benzene group, etc.)

（ｎは１～４の整数である。）

(N is an integer from 1 to 4.)

In the release film of the present invention, it is preferable to use a polythiophene having a structural formula represented by Chemical formula 2 or a polythiophene derivative. For example, in Chemical formula 2, n = 1 (methylene group) and n = 2 (ethylene group). , N = 3 (propylene group) compounds are preferred. Particularly preferred is a compound having an ethylene group of n = 2, that is, poly-3,4-ethylenedioxythiophene. Examples of the polythiophene or the polythiophene derivative include compounds in which a functional group is bonded to the 3-position and 4-position positions of the thiophene ring. As described above, a compound in which an oxygen atom is bonded to a carbon atom at the 3-position and a 4-position is preferable. For a compound having a structure in which a carbon atom or a hydrogen atom is directly bonded to the carbon atom, it may not be easy to make the coating liquid aqueous.
As a method for producing such a polymer, for example, the method shown in JP-A-7-96060 can be adopted.

In the release film of the present invention, the composition containing the polythiophene and the polyanion in the coating layer, or the composition containing the polythiophene derivative and the polyanion is preferable.
Examples of the poly anion used at the time of polymerization include poly (meth) acrylic acid, polymaleic acid, and polystyrene sulfonic acid. In addition, these acids may be partially or completely neutralized.
Particularly preferable modes include those using the compound of n = 2 in the above-mentioned Chemical formula 2 as the polythiophene and polystyrene sulfonic acid as the polyanion.

(Binder polymer (B))
The binder polymer (B) constituting the coating layer in the present invention is measured by gel permeation chromatography (GPC) according to the polymer compound safety evaluation flow scheme (sponsored by the Chemical Substances Council in November 1985). It is defined as a polymer compound having a number average molecular weight (Mn) of 1000 or more and having a film-forming property.

The binder polymer (B) constituting the coating layer in the present invention may be a thermosetting resin or a thermoplastic resin as long as it can be compatible with or mixed and dispersed with thiophene or a thiophene derivative. For example, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyimides such as polyimide and polyamideimide; polyamides such as polyamide 6, polyamide 6, 6, polyamide 12, and polyamide 11; polyvinylidene fluoride, polyvinyl chloride, and poly. Fluororesin such as tetrafluoroethylene, ethylene tetrafluoroethylene copolymer, polychlorotrifluoroethylene; vinyl resin such as polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate, polyvinyl chloride; epoxy resin; oxetane resin; xylene resin; Examples thereof include aramid resin; polyimide silicone; polyurethane; polyurea; melamine resin; phenol resin; polyether; acrylic resin and copolymers thereof.

The binder polymer (B) may be dissolved in an organic solvent, or may be imparted with a functional group such as a sulfo group or a carboxy group to form an aqueous solution. Further, the binder polymer (B) may be used in combination with a cross-linking agent, a curing agent such as a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier and the like, if necessary.

Among the binder polymers (B), any one or more selected from polyester resin, acrylic resin, and polyurethane resin is preferable because it is easy to mix at the time of preparing the coating liquid. Polyurethane resin is particularly preferable.

<Polyester resin>
The polyester resin used in the present invention is defined as a linear polyester containing a dicarboxylic acid component and a glycol component as constituent components. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 2,6 naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, and phenylindandicarboxylic acid. Examples thereof include dimer acid and the like. Two or more of these components can be used. Further, along with these components, a small proportion of unsaturated polybasic acids such as maleic acid, fumaric acid, itaconic acid and the like, p-hydroxybenzoic acid, p- (β-hydroxyethoxy) benzoic acid and the like. Can be used. The ratio of the unsaturated polybasic acid component and the hydroxycarboxylic acid component is at most 10 mol%, preferably 5 mol% or less.

The glycol components include ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, and dimethylolpropionic acid. , Glycerin, trimethylolpropane, poly (ethyleneoxy) glycol, poly (tetramethyleneoxy) glycol, alkylene oxide adduct of bisphenol A, alkylene oxide adduct of hydrogenated bisphenol A and the like can be exemplified. Two or more of these can be used.

Among such polyol components, ethylene glycol and bisphenol A ethylene oxide adducts and propylene oxide adducts and 1,4-butanediol are preferable, and ethylene glycol and bisphenol A ethylene oxide adducts and propylene oxide adducts are preferable. Further, the polyester resin can be copolymerized with a small amount of a compound having a sulfonic acid base or a compound having a carboxylic acid base in order to facilitate aqueous liquefaction, which is preferable. Examples of the compound having this sulfonic acid base include 5-sodium sulfoisophthalic acid, 5-ammonium sulfoisophthalic acid, 4-sodium sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid, 2-sodium sulfoisophthalic acid and 5-potassium. Preferred examples thereof include sulfonic acid alkali metal salt-based compounds such as sulfoisophthalic acid, 4-potassium sulfoisophthalic acid, 2-potassium sulfoisophthalic acid, and sodium sulfosuccinic acid, and sulfonic acid amine salt-based compounds.

Examples of the compound having this carboxylic acid base include trimellitic acid anhydride, trimellitic acid, pyromellitic acid anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylolpropionic acid and the like, or monoalkali metal salts thereof. And so on. The free carboxyl group is converted into a carboxylic acid base by allowing an alkali metal compound or an amine compound to act after copolymerization. Polyester obtained by appropriately selecting one or more of each of these compounds and synthesizing them by a conventional polycondensation reaction can be used.

With respect to the polyester resin, the glass transition temperature (hereinafter, may be abbreviated as Tg) is preferably 40 ° C. or higher, more preferably 60 ° C. or higher. If the Tg is less than 40 ° C., if the coating thickness of the coating layer is increased for the purpose of improving the adhesiveness, problems such as easy blocking may occur.

<Acrylic resin>
The acrylic resin is a polymer composed of a polymerizable monomer having a carbon-carbon double bond, as typified by acrylic and methacrylic monomers. These may be either homopolymers or copolymers. Further, a copolymer of these polymers and other polymers (for example, polyester, polyurethane, etc.) is also included. For example, block copolymers and graft copolymers. Further, a polymer (in some cases, a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyester solution or a polyester dispersion is also included. Similarly, a polymer (in some cases, a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyurethane solution or a polyurethane dispersion is also included. Similarly, a polymer (in some cases, a polymer mixture) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in another polymer solution or dispersion is also included.

The polymerizable monomer having a carbon-carbon double bond is not particularly limited, but typical compounds include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Various carboxyl group-containing monomers and salts thereof; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydroquilfumarate, monobutylhydroxy Various hydroxyl group-containing monomers such as itaconate; various (meth) acrylics such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate. Acid esters; Various nitrogen-containing vinyl-based monomers such as (meth) acrylamide, diacetone acrylamide, N-methylol acrylamide or (meth) acrylonitrile. In addition, the polymerizable monomers shown below can be copolymerized in combination with these. That is, various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, various vinyl esters such as vinyl acetate, vinyl propionate; γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, Various silicon-containing polymerizable monomers such as methacryloyl silicon macromer; phosphorus-containing vinyl monomers; vinyl chloride, vinyl chloride, vinyl fluoride, vinylidene fluoride, trifluorochlorethylene, tetrafluoroethylene, chlorotrifluoroethylene , Various vinyl halides such as hexafluoropropylene; various conjugated dienes such as butadiene and the like are exemplified.

In the acrylic resin, the glass transition temperature (hereinafter, may be abbreviated as Tg) is preferably 40 ° C. or higher, more preferably 60 ° C. or higher. If the Tg is less than 40 ° C., if the coating thickness of the coating layer is increased for the purpose of improving the adhesiveness, problems such as easy blocking may occur.

<Urethane resin>
The polyurethane resin in the present invention refers to a polymer compound having a urethane bond in the molecule. Among them, a water-dispersible or water-soluble urethane resin is preferable in consideration of suitability for in-line coating. In order to impart water dispersibility or water solubility, a hydrophilic group such as a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfonyl group, a phosphoric acid group or an ether group can be introduced into the urethane resin. Among the hydrophilic groups, a carboxylic acid group or a sulfonic acid group is preferably used from the viewpoint of improving the physical properties of the coating film and the adhesion.

As a specific production example of the urethane resin, for example, a method using a reaction between a hydroxyl group and an isocyanate can be mentioned. As the hydroxyl group used as a raw material, a polyol is preferably used, and examples thereof include polyether polyols, polyester polyols, polycarbonate-based polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination of two or more.

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

Polypolycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimylene acid, sveric acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides include polyester polyols. Products and polyhydric alcohols (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, cyclohexanediol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamine, lactonediol, etc.) can be mentioned.

Examples of the polycarbonate-based polyols include polyhydric alcohols and polycarbonate diols obtained by dealcoholization reaction from dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate and the like, for example, poly (1,6-hexylene) carbonate and poly (poly (1,6-hexylene) carbonate). 3-Methyl-1,5-pentylene) carbonate and the like can be mentioned.

Examples of the polyisocyanate compound used to obtain a urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylenedi isocyanate, naphthalenedi isocyanate, and trizine diisocyanate, α, α, α', and α'. -A aliphatic diisocyanate having an aromatic ring such as tetramethylxylylene diisocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate and other aliphatic diisocyanates, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Examples thereof include alicyclic diisocyanates such as methane diisocyanate and isopropyridene dicyclohexyl diisocyanate. These may be used alone or in combination of two or more.

When synthesizing the urethane resin, a conventionally known chain extender may be used, and the chain extender is not particularly limited as long as it has two or more active groups that react with isocyanate groups. , A chain extender having two hydroxyl groups or amino groups is commonly 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. Examples thereof include glycols such as glycols. Examples of the chain extender having two amino groups include aromatic diamines such as tolylene diamine, xylylene diamine, 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-nonandiamine, 1,10- Aliper diamines such as decanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isoprovilitincyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, 1, , 3-Bisaminomethylcyclohexane and other alicyclic diamines and the like.

In the present invention, the coating layer constituting the release film preferably contains a polyurethane resin for the purpose of improving the adhesiveness to the release layer.

The coating liquid for providing the coating layer in the present invention is further selected from the group of glycerin (C1), polyglycerin (C2), glycerin or an alkylene oxide adduct of polyglycerin (C3) as the component (C) 1. It is preferable to contain a compound of more than one species or a derivative thereof. It is more preferable that the average number of glycerin units in the molecule is in the range of 2 to 20.

Further, the alkylene oxide adduct of glycerin or polyglycerin has a structure in which an alkylene oxide or a derivative thereof is addition-polymerized to the hydroxyl group of glycerin or polyglycerin.

Here, the structure of the added alkylene oxide or its derivative may be different for each hydroxyl group of the glycerin or polyglycerin skeleton. Further, it is sufficient that it is added to at least one hydroxyl group in the molecule, and it is not necessary that an alkylene oxide or a derivative thereof is added to all the hydroxyl groups.

A preferred alkylene oxide or derivative thereof is a structure containing an ethylene oxide or a propylene oxide skeleton. If the alkyl chain in the alkylene oxide structure becomes too long, the hydrophobicity becomes strong, the uniform dispersibility in the coating liquid deteriorates, and the antistatic property and transparency of the coating film tend to deteriorate. Particularly preferred is ethylene oxide.

In the alkylene oxide adduct of such glycerin or polyglycerin, the copolymerization ratio of the alkylene oxide or its derivative with respect to the glycerin or polyglycerin skeleton is not particularly limited, but when the glycerin or polyglycerin moiety is set to 1 in terms of molecular weight ratio, The alkylene oxide moiety is preferably 20 or less, more preferably 10 or less. When the ratio of the alkylene oxide or its derivative to the glycerin or the polyglycerin skeleton is larger than this range, the characteristics are close to those when the usual polyalkylene oxide is used, and the effect of the present invention may not be sufficiently obtained. be.

Particularly preferred embodiments of the component (C) in the present invention include polyglycerin (C2) and glycerin or an alkylene oxide adduct of polyglycerin (C3). As the polyglycerin (C2), among the following compounds of Chemical formula 3, those having n of 2 to 20 are particularly preferable. Further, as the alkylene oxide adduct (C3) of glycerin or polyglycerin, the compound having the structure in which ethylene oxide and polyethylene oxide are added to n = 2 in the following compound of Chemical formula 3 is particularly preferable, and the addition number thereof is particularly preferable. The final compound (C3) having a weight average molecular weight in the range of 300 to 2000 is particularly preferable.

The blending ratio of the component (C) in the coating layer is in the range of 10 to 90% by weight, more preferably in the range of 20 to 80% by weight. If the range is less than 10% by weight, the coatability may decrease. On the other hand, if it exceeds 90% by weight, the durability of the coating layer may be insufficient.

In the present invention, with respect to the coating layer constituting the release film, the weight of the conductive compound (A) in the coating layer is preferably 0.5 mg / m ² or more, more preferably 1 mg / m ² or more. good. When the amount of the conductive compound (A) is 0.5 mg / m ² or more, sufficient antistatic properties can be obtained.

Further, in the present invention, the ratio of the conductive compound (A) to the coating layer constituting the release film is not limited, but the upper limit is preferably 90% by weight or less, more preferably 80% by weight or less, and most preferably. It is 60% by weight or less. When the ratio of the conductive compound (A) exceeds 90% by weight, the transparency of the coating layer may be insufficient or the antistatic performance may be insufficient. On the other hand, the lower limit is preferably 1% by weight or more, more preferably 2% by weight or more. If the weight ratio of the conductive compound (A) is less than 1% by weight, the antistatic performance may be insufficient.

In the coating layer constituting the release film of the present invention, the ratio of the conductive compound (A) to the binder polymer (B) is preferably in the range of 90/10 to 1/99 by weight, more preferably. The range is preferably 70/30 to 1/99, and most preferably 50/50 to 2/98. If it is out of this range, the antistatic performance or the appearance of the coating film tends to deteriorate.

The coating liquid used in the present invention is a defoaming agent, a coating property improving agent, a thickener, an organic lubricant, a mold release agent, an organic particle, an inorganic particle, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, and the like. It may contain an additive such as a pigment. These additives may be used alone, or two or more thereof may be used in combination if necessary.

The coating liquid in the present invention is preferably an aqueous solution or an aqueous dispersion from the viewpoints of handling, working environment, and stability of the coating liquid composition, but water is the main medium, which is beyond the gist of the present invention. An organic solvent may be contained as long as it does not exist.

The coating layer in the present invention is provided by applying a coating liquid containing a specific compound to a film, and in particular, in the present invention, it is preferably provided by in-line coating in which coating is performed during film formation.

[Silicone mold release layer]
The silicone-based release layer is formed by using the following release agent composition. The release agent composition in the present embodiment has a first polydimethylsiloxane having at least one alkenyl group in one molecule and at least one hydrosilyl group in one molecule as an addition reaction type silicone resin. Contains a second polydimethylsiloxane.

Examples of the alkenyl group contained in the first polydimethylsiloxane used in the present invention include a monovalent hydrocarbon group such as a vinyl group, an allyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group and an octenyl group. Among them, a vinyl group and a hexenyl group are preferable.

In 30 g of the first polydimethylsiloxane, the alkenyl group (a) is preferably contained in an amount of 3 to 90 mmol, more preferably 6 to 45 mmol. Further, 30 g of the second polydimethylsiloxane contains preferably 6 to 450 mmol of the hydrosilyl group (b), and more preferably 15 to 450 mmol. Further, the molar ratio (b / a) of the hydrosilyl group (b) to the alkenyl group (a) is preferably 1.5 to 5.0, more preferably 1.5 to 3.0.

The weight average molecular weight of the first polydimethylsiloxane is indispensable to be 500 or more and 30,000 or less, preferably 1000 or more or 20,000 or less, and more preferably 2000 or more or 10,000 or less. When the weight average molecular weight of the first polydimethylsiloxane is less than 500, the reactivity is high and the reaction proceeds in the compounding solution, so that the desired light peeling force is not exhibited, and when it exceeds 30,000, the reactivity is poor. Therefore, the desired light peeling force is not exhibited.
The content of the first polydimethylsiloxane in the release agent composition is preferably 40 to 90% by weight, more preferably 50 to 80% by weight.

The weight average molecular weight of the second polydimethylsiloxane is indispensable to be 120 or more and 10000 or less, preferably 150 or more or 5000 or less, and more preferably 200 or more or 2000 or less. If the weight average molecular weight of the second polydimethylsiloxane is less than 120, the reactivity is high and the reaction proceeds in the compounding solution, so that the desired light peeling force is not exhibited, and if it exceeds 10,000, the reactivity is poor. Therefore, the desired light peeling force is not exhibited. The weight average molecular weight in the present invention is a polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method.
The content of the second polydimethylsiloxane in the release agent composition is preferably 10 to 60% by weight, more preferably 20 to 50% by weight.

In the release film of the present invention, a platinum-based catalyst that promotes the addition type reaction is used in order to make the silicone-based release layer clean and sturdy. This component includes platinum chloride acid, an alcohol solution of platinum chloride acid, a platinum-based compound such as a complex of platinum chloride acid and an olefin, a complex of platinum chloride acid and an alkenylsiloxane, platinum black, platinum-supported silica, and platinum-supported activated carbon. Is exemplified. The platinum-based catalyst content in the silicone-based mold release layer is usually in the range of 0.3 to 3.0% by weight, preferably 0.5 to 2.0% by weight. If the platinum-based catalyst content in the silicone-based release layer is lower than 0.3% by weight, problems such as poor peeling force and insufficient curing reaction in the coating layer will occur, resulting in problems such as surface deterioration. On the other hand, if the platinum-based catalyst content in the silicone-based release layer exceeds 3.0% by weight, it is costly, the reactivity is increased, and gel foreign matter is generated. May occur.

By forming the silicone-based mold release layer using a mold release agent composition that satisfies the above conditions, when the light release mold release film is peeled from the pressure-sensitive adhesive layer in the use of a substrate-less double-sided pressure-sensitive adhesive sheet, The light release mold release film can be peeled off extremely smoothly.

In the release agent composition of the present invention, unreactive organopolysiloxane may be further added as one of the unreactive silicone resins in order to impart light peelability. The weight average molecular weight of the unreactive organopolysiloxane is preferably 50,000 or more and 500,000 or less.

As the unreactive silicone resin, an organopolysiloxane represented by the following general formula (I) is preferable.
R ₃ SiO (R ₂ SiO) _m SiR ₃ …… (I)
(In the formula, R represents the same or different monovalent hydrocarbon group having no aliphatic unsaturated bond, and m represents a positive integer.)

The content of the unreactive silicone resin used in the release agent composition of the present invention is usually in the range of 1 to 10% by weight, preferably 1 to 5% by weight. When the content of the unreactive silicone resin is 1% by weight or more, a sufficient light peeling effect is exhibited, and when the content is 5% by weight or less, sufficient curability and adhesion can be obtained.

In the present invention, silicone oil may be added in order to reduce the peeling force. Silicone oil is a silicone oil called straight silicone oil or modified silicone oil, and examples thereof include the following. Examples of straight silicone include dimethyl silicone oil, methyl phenyl silicone oil, and methyl hydrogen silicone oil. The modified silicone oil includes side chain type polyether modification, aralkyl modification, fluoroalkyl modification, long chain alkyl modification, higher fatty acid ester modification, higher fatty acid amide modification, polyether / long chain alkyl modification / aralkyl modification, etc. Examples thereof include phenyl denaturation, double-ended type polyether denaturation, and polyether methoxy denaturation.

For the release agent composition of the present invention, the silicone oil component is usually in the range of 1 to 10% by weight, preferably 1 to 5% by weight. If the content of the silicone oil component is lower than 1% by weight, the speed dependence on the peeling force may become high, and if it exceeds 5% by weight, the transferability is high, and it may be on roll stains or the adhesive surface during adhesive processing. There is a possibility that the adhesive peeling force may decrease due to the migration.

Further, it is preferable to use an addition reaction type silicone resin for the release agent composition used in the present invention. Since the addition reaction type is very reactive, acetylene alcohol may be added as a reaction inhibitor in some cases. Its constituents are organic compounds with carbon-carbon triple bonds and hydroxyl groups, but preferably 3-methyl-1-butyne-3-ol, 3,5-dimethyl-1-hexin-3-ol and phenylbuty. It is a compound selected from the group consisting of Noll.

The method of forming the silicone-based mold release layer on at least one surface of the polyester film is not particularly limited, but a method of applying a mold release agent composition (coating liquid) in the process of producing the polyester film is preferably adopted. Specifically, a method of applying a coating liquid to the surface of an unstretched sheet and drying, a method of applying a coating liquid to the surface of a uniaxially stretched film and drying, and a method of applying a coating liquid to the surface of a biaxially stretched film and drying it. And so on. Among these, a method of applying a coating liquid to the surface of an unstretched film or a uniaxially stretched film and then drying and curing the silicone-based release layer at the same time in the process of heat-treating the film is economical.
Further, as a method for forming the silicone-based release layer, a method in which some of the above-mentioned coating methods are used in combination can also be adopted, if necessary. Specific examples thereof include a method in which the first layer is applied to the surface of the unstretched sheet and dried, then stretched in the uniaxial direction, and then the second layer is applied and dried. As a method of applying the coating liquid to the surface of the polyester film, Yuji Harasaki, Maki Shoten, published in 1979, reverse roll coater, gravure coater, rod coater, air doctor coater, and other bars shown in "Coating method". A coater, a doctor blade coater, etc. can be used.

The coating amount of the silicone-based release layer in the present invention is usually preferably in the range of 0.01 to 1 g / m ² , but more preferably 0.15 to 0.70 g / m ² .

In the present invention, even if a coating layer such as an adhesive layer, an antistatic layer, an oligomer precipitation prevention layer, etc. is provided between the surface on which the silicone-based mold release layer is not provided or between the polyester film and the silicone-based mold release layer. Also, the polyester film may be subjected to surface treatment such as corona treatment and plasma treatment.

In the present invention, the residual adhesion ratio of the tape (Nitto Denko Corporation, No. 31B tape) is preferably 80% or more, more preferably 85% or more. If the residual adhesive ratio is lower than 80%, the transferability is high, and the adhesive is transferred to the roll stain or the adhesive surface during the adhesive processing, resulting in a decrease in the adhesive peeling force.

In the present invention, the peeling force of the silicone-based mold release layer surface at 300 mm / min by the adhesive tape (“tesa7475” manufactured by tesa) is preferably 9 g / 25 mm or less, more preferably 8 g / 25 mm or less. If the peeling force exceeds 9 g / 25 mm, when the release film is used for protecting the pressure-sensitive adhesive layer, there may be a problem that the release film cannot be peeled off cleanly from the pressure-sensitive adhesive. On the other hand, the lower limit of the peeling force is not particularly limited, but 1 g / 25 mm or more is more preferable, and 3 g / 25 mm or more is further preferable.

Further, as the peeling speed increases, the peeling force tends to increase, and if the peeling speed is increased, a problem may occur in which the peeling force cannot be peeled off cleanly.
In the present invention, the peeling force of the adhesive tape (“tea7475” manufactured by tessa) at 30 m / min is preferably 250 g / 25 mm or less, more preferably 200 g / 25 mm or less. When the release force is 250 g / 25 mm or less, when the release film is used for the adhesive layer protection application, the release film can be easily peeled off from the adhesive, which is also effective from the viewpoint of productivity.
On the other hand, the lower limit of the peeling force is not particularly limited, but 10 g / 25 mm or more is more preferable, and 25 g / 25 mm or more is further preferable.

In the present invention, the peeling force means that an adhesive tape (“tea7475” manufactured by tessa) is attached to a silicone-based mold release layer surface and left at room temperature for 1 hour, and then the polyester film has a peeling angle of 180 ° and a specific tensile speed. (Peeling speed) refers to the value measured by the tensile tester when the tape is peeled off. In the present invention, a method for adjusting a specific peeling force can be achieved by selecting the composition in the silicone-based release layer, but other means can also be adopted, and a release agent for the silicone release layer is mainly used. It is preferable to change the type of the release agent composition according to the desired release force, and further, since the release force greatly depends on the application amount of the release agent composition to be used, the application amount of the release agent composition is adjusted. The method is more preferred.

[Adhesive layer]
The release film of the present invention is suitable for bonding to the pressure-sensitive adhesive layer.
The pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer is not particularly limited, and specific examples thereof include a silicone-based pressure-sensitive adhesive, an acrylic-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and an epoxy pressure-sensitive adhesive. Among them, an acrylic pressure-sensitive adhesive is preferable, and an acrylic solvent-based pressure-sensitive adhesive is more preferable, from the viewpoint that the pressure-sensitive adhesive property can be adjusted in a wide range and is widely used.

Further, in the pressure-sensitive adhesive composition, additives such as stabilizers, hardeners, tackifiers, fillers, colorants, antioxidants, antistatic agents, and surfactants are added to the range that does not impair the gist of the present invention. Can be used as needed.

The solvent used in the pressure-sensitive adhesive composition is not particularly limited, but it is preferable to use a solvent that can be appropriately uniformly and stably dissolved or dispersed. Examples of the solvent include alcohols (methanol, ethanol, propanol, isopropanol, n-butanol, s-butanol, t-butanol, benzyl alcohol, PGME, ethylene glycol, diacetone alcohol); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, Cyclopentanone, cyclohexanone, heptanone, diisobutylketone, diethylketone, diacetone alcohol); esters (methyl acetate, ethyl acetate, butyl acetate, n-propyl acetate, isopropyl acetate, methyl acrylate, PGMEA); aliphatic hydrocarbons (hexane) , Cyclohexane); halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride); aromatic hydrocarbons (benzene, toluene, xylene); amides (dimethylformamide, dimethylacetamide, n-methylpyrrolidone); ethers (diethyl ether, Dioxane, tetrahydrofuran); ether alcohol (1-methoxy-2-propanol); carbonates (dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate) and the like. These solvents may be used alone or in combination of two or more.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Measurement of average particle size (d50: μm):
The value of 50% integrated (weight basis) in the equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) was taken as the average particle size.

(2) Evaluation of release force of release film:
After attaching one side of an adhesive tape (“tea7475” manufactured by tesa) to the surface of the silicone-based release layer of the sample film, the peeling force after being left at room temperature for 1 hour is measured. The peeling force was 180 ° peeling under the condition of a tensile speed of 300 mm / min using a tensile tester (“Intesco Model 2001” manufactured by Intesco). The evaluation results are shown in Table 2A and Table 3B.

(3) Transferability alternative evaluation of release film (residual adhesion rate):
The sample film is cut into A4 size, and an adhesive tape (“No. 31B” manufactured by Nitto Denko Co., Ltd.) is attached to the measurement surface of the film using a rubber roller. After 1 hour, the adhesive tape is peeled off and the adhesive tape is attached. Is attached to a stainless steel plate whose surface has been cleaned using a rubber roller. An adhesive tape is fixed to the upper chuck and a stainless steel plate is fixed to the lower chuck, and the adhesive force (I) is measured by peeling off the adhesive tape at a speed of 300 mm / min in the 180 ° direction.
Adhesive strength (II) is measured by the same procedure as described above using an adhesive tape (“No. 31B” manufactured by Nitto Denko Co., Ltd.) that is not bonded to the sample. The residual adhesion ratio is calculated by the following formula. The evaluation results are shown in Table 2A and Table 3B.
Residual adhesion rate (%) = {adhesive strength (I) / adhesive strength (II)} x 100

(4) Surface intrinsic resistance of the release film The surface intrinsic resistance on the surface of the release layer of the sample film was measured based on the method of (4-1) below. Since the surface intrinsic resistance higher than 1 × 108Ω cannot be measured by the method (4-1), the method (4-2) was used for the sample that could not be measured by (4-1). The evaluation results are shown in Table 3B.
"Measuring method"
(4-1) Using a low resistivity meter manufactured by Mitsubishi Chemical Corporation: Loresta GPMCP-T600, the sample was adjusted for 30 minutes in a measurement atmosphere at 23 ° C. and 50% RH, and then the surface intrinsic resistance value was measured.
(4-2) Using a high resistance measuring instrument: HP4339B and a measuring electrode: HP16008B manufactured by Hewlett-Packard Japan, measure the surface intrinsic resistance value after adjusting the humidity of the sample for 30 minutes in a measuring atmosphere at 23 ° C. and 50% RH. did.
"Evaluation criteria"
⊚: R (Ω) is 1 × ¹⁰⁸ or less (practical and particularly good)
◯: R (Ω) is ¹ × 109 or less (practical)
Δ: R (Ω) is 1 × 10 ¹⁰ or less (may cause practical problems)
×: R (Ω) exceeds 1 × 10 ¹⁰ (practical difficulty)

(5) Evaluation of coating film adhesion of release film (evaluation of practical characteristics substitute)
The sample film was left in a constant temperature and humidity chamber at 60 ° C. and an 80% RH atmosphere for 4 weeks, and then the sample film was taken out. Then, the release surface of the sample film was rubbed with a tentacle five times, and the degree of detachment of the release layer was evaluated according to the following evaluation criteria.
"Evaluation criteria"
◯: No peeling of the coating film is seen (practical and particularly good)
Δ: The coating film becomes white but has not fallen off (practical)
X: It was confirmed that the coating film had fallen off (difficult to put into practical use).

(6) Release characteristics (practical alternative evaluation):
An acrylic pressure-sensitive adhesive composition having the following composition was applied to the release film and then heat-treated at 100 ° C. for 5 minutes to obtain a pressure-sensitive adhesive having a thickness of 200 μm after drying. After that, the release film and the adhesive adhesive were stored at room temperature for one week, then the release film was peeled off, and the release characteristics were evaluated according to the following evaluation criteria from the situation when the release film was peeled off from the adhesive. did. The evaluation results are shown in Table 2A and Table 3B.
<< Acrylic adhesive composition >>
Main agent: AT352 (manufactured by Saiden Chemical Co., Ltd.) 100 parts by weight Hardener: AL (manufactured by Saiden Chemical Co., Ltd.) 0.25 parts by weight Additive: X-301-375SK (manufactured by Saiden Chemical Co., Ltd.) 0.25 parts by weight Additive: X -301-352S (manufactured by Saiden Chemical Co., Ltd.) 0.4 parts by weight Toluene: 40 parts by weight << Evaluation Criteria >>
◯: The release film is peeled off cleanly, and the phenomenon that the adhesive adheres to the silicone-based release layer is not observed.
Δ: The release film is peeled off, but when the release film is peeled off at a high speed, the adhesive adheres to the silicone-based release layer.
X: Adhesive adheres to the release film and does not peel off well.

The polyesters used in Examples and Comparative Examples were prepared as follows.

<Manufacturing of polyester>
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 was taken in a reactor, the reaction start temperature was set to 150 ° C., and gradually with the distillation of methanol. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. After 0.04 part by weight of ethyl acid phosphate was added to this reaction mixture, 0.06 part by weight of silica particles dispersed in ethylene glycol having an average particle size of 1.6 μm and 0.04 part by weight of antimony trioxide were added. The polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually increased from 230 ° C to 280 ° C. On the other hand, the pressure was gradually reduced from the normal pressure to finally reach 0.3 mmHg. After 4 hours from the start of the reaction, the reaction was stopped and the polymer under nitrogen pressure was discharged. The ultimate viscosity of the obtained polyester was 0.53 dl / g.

<Manufacturing of mold release film>
The following Examples 1A to 4A and Comparative Examples 1A to 6A are for explaining the first invention, and the following Examples 1B to 4B and Comparative Examples 1B to 6B are for explaining the second invention.

[Example 1A]
The polyester (1) described above is used as a raw material, supplied to an extruder with a vent, melt-extruded at 290 ° C, and then cooled and solidified on a cooling roll whose surface temperature is set to 40 ° C using an electrostatic application adhesion method. Amorphous film having a thickness of about 550 μm was obtained.
This film was stretched 3.7 times in the vertical direction at 85 ° C., stretched 3.9 times in the horizontal direction at 100 ° C., and heat-treated at 210 ° C. to obtain a biaxially stretched polyester film having a thickness of 38 μm.

The release agent composition shown below was applied to the obtained polyester film by a reverse gravure coating method so that the coating amount (after drying) was 0.200 g / m ² , and the dryer temperature was 150 ° C. and the line speed was 30 m / m. A roll-shaped release film was obtained under the condition of minutes. The evaluation results of the release film are shown in Table 2A.

Further, as a result of peeling the release film obtained in Example 1A by 180 ° at a tensile speed of 30 m / min, the peeling force was 108 g / 25 mm. The conditions regarding the peeling force were the same as in (2) above except that the tensile speed was changed to 30 m / min.

<Release composition>
As the first polydimethylsiloxane, a vinyl-modified silicone resin (weight average molecular weight: 2000) having at least two vinyl groups in the structure of the polydimethylsiloxane, and as the second polydimethylsiloxane, in the structure of the polydimethylsiloxane. Polymethylhydrogensiloxane (weight average molecular weight: 200) having at least two hydrosilyl groups was mixed so that the first polydimethylsiloxane / second polydimethylsiloxane = 77/22, and the solid content was 3% by weight. After diluting with a solvent having a blending ratio of toluene / MEK / hexane = 1/1/18, 2 parts by weight of a platinum-based catalyst (SRX-212 manufactured by Toray Dow Corning) was added to form a release agent composition. Got
The weight portion of the platinum-based catalyst is a value when the total number of copies of the first polydimethylsiloxane and the second polydimethylsiloxane is 100.

[Examples 2A to 4A], [Comparative Examples 1A to 6A]
The silicone-based mold release layer was produced in the same manner as in Example 1A except that the mold release agent composition shown in Table 1A was changed, to obtain a mold release film. The evaluation results of the release film are shown in Table 2A.
<Raw material for mold release agent composition>
a1: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 2000)
a2: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 20000)
a3: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 1000)
a4: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 60000)
a5: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 300)
b1: Polymethylhydrogensiloxane having at least two hydrosilyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 200)
b2: Polymethylhydrogensiloxane having at least one hydrosilyl group in the structure of polydimethylsiloxane (weight average molecular weight: 5000)
b3: Polymethylhydrogensiloxane having at least one hydrosilyl group in the structure of polydimethylsiloxane (weight average molecular weight: 30,000)
b4: Polymethylhydrogensiloxane having at least two hydrosilyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 100)
c1: Platinum-based catalyst ("SRX-212" manufactured by Toray Dow Corning)

Further, as a result of peeling the release film obtained in Example 4A by 180 ° at a tensile speed of 30 m / min, the peeling force was 112 g / 25 mm. The conditions regarding the peeling force were the same as in (2) above except that the tensile speed was changed to 30 m / min.

[Comparative Example 7A]
The release agent composition was not applied to the biaxially stretched polyester film obtained in Example 1A, and the polyester film having no silicone-based release layer was used as the release film. The evaluation results of the release film are shown in Table 2A.

[Example 1B]
The polyester (1) described above is used as a raw material, supplied to an extruder with a vent, melt-extruded at 290 ° C, and then cooled and solidified on a cooling roll whose surface temperature is set to 40 ° C using an electrostatic application adhesion method. Amorphous film having a thickness of about 550 μm was obtained.
This film was stretched 3.7 times in the vertical direction at 85 ° C., and a coating layer composed of the following coating agent composition was applied so as to have a thickness (after drying) of 0.03 g / m ² , and then 100 ° C. The film was stretched 3.9 times in the lateral direction and heat-treated at 210 ° C. to obtain a biaxially stretched polyester film having a thickness of 38 μm.

<Coating composition>
A: Consists of polyethylene dioxythiophene and polystyrene sulfonic acid,
Baytron PAG manufactured by Stark Co., Ltd.
B: Polyurethane resin A polyester polyol consisting of 664 parts by weight of terephthalic acid, 631 parts by weight of isophthalic acid, 472 parts by weight of 1,4-butanediol, and 447 parts by weight of neopentyl glycol was obtained. Next, 321 parts by weight of adipic acid and 268 parts by weight of dimethylolpropionic acid were added to the obtained polyester polyol to obtain a pendant carboxyl group-containing polyester polyol A. Further, 1880 parts by weight of the polyester polyol A and 160 parts by weight of hexamethylene diisocyanate were added to obtain a polyurethane coating composition.
C: Glycerin compounding weight ratio of n = 1 in the above formula (3): A / B / C = 40/40/20 (% by weight)

The above-mentioned mold release agent composition used for explaining the first invention was applied to the obtained polyester film by a reverse gravure coating method so that the coating amount (after drying) was 0.200 g / m ² , and the dryer temperature was reached. A roll-shaped release film was obtained under the conditions of 150 ° C. and a line speed of 30 m / min.

[Examples 2B to 5B], [Comparative Examples 1B to 10B]
The coating layer and the release layer were produced in the same manner as in Example 1B except that the coating composition and the release agent composition shown in Tables 1B and 2B were changed, and a release film was obtained.

[Comparative Example 10B]
The biaxially stretched polyester film obtained in Example 1 was not coated with a release agent, and a polyester film having no release layer was used as the release film.

Claims (2)

A first polydimethylsiloxane having a weight average molecular weight of 500 or more and 30,000 or less and having at least one alkenyl group in one molecule and a weight average molecular weight of 150 or more and 10,000 or less on at least one side of the polyester film. 1. The release agent composition having a silicone-based release layer composed of a release agent composition containing a second polydimethylsiloxane having at least one hydrosilyl group in one molecule and a platinum-based catalyst. The content of the first polydimethylsiloxane is 40 to 80% by weight, the content of the second polydimethylsiloxane is 20 to 60% by weight, and each of them in the release agent composition. A release film characterized in that the total content of the components is 100% by weight. A release film in which a coating layer and a release layer are sequentially provided on at least one side of a polyester film, and the coating layer contains a conductive compound (A) and a binder polymer (B), and the release layer is contained. However, the first polydimethylsiloxane having a weight average molecular weight of 500 or more and 30,000 or less and having at least one alkenyl group in one molecule and a weight average molecular weight of 150 or more and 10,000 or less in one molecule. It is a silicone-based mold release layer composed of a mold release agent composition containing a second polydimethylsiloxane having at least one hydrosilyl group and a platinum-based catalyst, and is the first in the mold release agent composition. The content of the polydimethylsiloxane is 40 to 80% by weight, the content of the second polydimethylsiloxane is 20 to 60% by weight, and the total content of each component in the release agent composition is. A release film characterized by being 100% by weight.