CN108883615B

CN108883615B - Mold release film

Info

Publication number: CN108883615B
Application number: CN201780021541.4A
Authority: CN
Inventors: 铃木太朗
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2016-05-20
Filing date: 2017-05-18
Publication date: 2020-11-10
Anticipated expiration: 2037-05-18
Also published as: KR20180124063A; JPWO2017200056A1; JP7003915B2; WO2017200056A1; CN108883615A

Abstract

The invention provides a release film which has good release property of a self-adhesive and less transferability and is suitable for various adhesive layer protection applications. A release film comprising a polyester film and, formed on at least one surface thereof, a silicone-based release layer formed from a release agent composition comprising: a1 st polydimethylsiloxane having a weight-average molecular weight of 500 or more and 30000 or less and having at least 1 alkenyl group in 1 molecule; a2 nd polydimethylsiloxane having a weight-average molecular weight of 150 to 10000 inclusive and having at least 1 hydrosilyl group in 1 molecule; and a platinum group catalyst.

Description

Mold release film

Technical Field

The present invention relates to a release film.

Background

Conventionally, release films based on polyester films have been used for various applications (for example, touch panels of electrostatic capacity type, polarizing plates for LCD, retardation plates, PDP components, organic EL components, various display components, and various optical applications) in which they are bonded to each other through an adhesive layer.

The substrate-less double-sided pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet formed by laminating a light release film having a relatively low peeling force and a heavy release film having a relatively high peeling force on both sides of a pressure-sensitive adhesive layer, and only the pressure-sensitive adhesive layer having no supporting substrate is formed after removing the release films on both sides.

As a method of using the substrate-less double-sided adhesive sheet, the following processing steps can be exemplified: the light release film is first peeled off, one surface of the exposed adhesive layer is bonded to the surface of an object to be bonded, and after the bonding, the heavy release film is further peeled off, and the other surface of the exposed adhesive layer is bonded to a different object surface, whereby surface bonding is performed between the objects.

In recent years, a substrate-less double-sided pressure-sensitive adhesive sheet has attracted attention in view of its excellent handling properties, and its applications are expanding, and it is also used for members for various optical applications, for example, mobile phones. In particular, the capacitance type touch panel is in a state of rapidly expanding its application as an information terminal by a multi-touch operation of a screen operation with two fingers. In the capacitance type touch panel, the printed step tends to be thicker in structure than in the resistance film type touch panel, and thus it is proposed to increase the thickness of the adhesive layer to eliminate the printed step. When the adhesive layer is thickened, there may be a case where a part of the adhesive layer adheres to the release film or a case where air bubbles are mixed into the adhesive layer transferred to the release film when the release film is peeled. Therefore, the current situation is: when a substrate-less double-sided adhesive sheet is used for optical applications, not only the substrate-less double-sided adhesive sheet but also a release film to be combined is more severe than ever, and a higher quality release film is required.

When the light-peeling release film is peeled from the adhesive layer in the use of the substrate-less double-sided adhesive sheet, the light-peeling release film has a high peeling force and cannot be peeled from the adhesive favorably, which is problematic.

As a solution to the above problem, for example, patent documents 1 to 3 propose that the peeling speed of the release layer is set to a certain level or lower. However, the release films described in patent documents 1 to 3 have a problem that the light peeling is insufficient and cannot be fully handled.

In addition, when a release film is used, peeling static electricity may be generated when peeling from the adhesive layer, and as a result, defects such as product defects due to adhesion or entanglement of foreign matters and the like may occur when a member is manufactured. Therefore, the current situation is: antistatic measures are not necessarily sufficient only by the equipment handling in the production process, and antistatic treatment derived from the release film itself is strongly desired.

As a solution to the above problem, for example, patent documents 4 and 5 propose an antistatic layer containing a pi-electron conjugated conductive polymer. In the antistatic film described in this document, the releasing layer may not have sufficient adhesion to the antistatic layer when the releasing layer is provided on the antistatic layer, on the other hand, antistatic property is good.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2012-25088

Patent document 2: japanese patent laid-open No. 2012-179888

Patent document 3: japanese patent laid-open publication No. 2015-142999

Patent document 4: japanese patent laid-open No. 2012 and 183811

Patent document 5: japanese laid-open patent publication No. 2012-993

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a release film which has good releasability from an adhesive and little transferability to an adhesive member regardless of the peeling speed at the time of use.

Further, the problem to be solved by the invention of claim 2 is to provide a release film which is excellent in releasability from an adhesive, less in transferability to an adhesive member and excellent in antistatic property regardless of the peeling speed at the time of use.

Means for solving the problems

The present inventors have conducted extensive studies in view of the above circumstances, and as a result, have found that the above problems can be easily solved by using a polyester film having a specific structure, and have completed the present invention.

That is, the above technical object of the present invention can be achieved by the following present invention.

(1) The present invention is a release film having a silicone-based release layer formed from a release agent composition on at least one surface of a polyester film, the release agent composition containing: a1 st polydimethylsiloxane having a weight-average molecular weight of 500 to 30000 inclusive and having at least 1 alkenyl group in 1 molecule, and a2 nd polydimethylsiloxane having a weight-average molecular weight of 150 to 10000 inclusive and having at least 1 hydrosilyl group in 1 molecule, and containing a platinum-based catalyst (invention 1).

(2) The present invention is a polyester film, which is a release film comprising a polyester film and, sequentially provided on at least one surface thereof, a coating layer and a release layer, the coating layer comprising a conductive compound (a) and a binder polymer (B), the release layer being a silicone-based release layer formed from a release agent composition comprising: a1 st polydimethylsiloxane having a weight-average molecular weight of 500 or more and 30000 or less and having at least 1 alkenyl group in 1 molecule; a2 nd polydimethylsiloxane having a weight-average molecular weight of 150 to 10000 inclusive and having at least 1 hydrosilyl group in 1 molecule; and a platinum group catalyst (invention 2).

In the present invention, it is preferable that the release force between the surface of the silicone-based release layer and the adhesive tape at a release rate of 300mm/min is 9g/25mm or less.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the above problems can be solved.

The release film of the present invention is suitable for various adhesive layer protection applications, in addition to applications for manufacturing various display constituent members, such as a substrate-free double-sided adhesive sheet for manufacturing a touch panel, a touch panel of an electrostatic capacitance system, a polarizing plate used in a Liquid Crystal Display (LCD), an LCD constituent member such as a retardation plate, a plasma display panel constituent member, an organic electroluminescence constituent member, and the like.

Detailed Description

The present invention is based on the finding that the present invention 1 has a layer structure of a polyester film/a silicone-based release layer, and the present invention 2 has a layer structure of a polyester film/a coating layer/a silicone-based release layer. The polyester film, the coating layer, and the silicone-based release layer are described below in this order.

[ polyester film ]

When a release film is used for adhesive protection, a part of the adhesive layer may adhere to the release film during peeling. It is considered that when the pressure-sensitive adhesive adheres to the release film, the surface shape of the pressure-sensitive adhesive layer becomes rough, and the adhesion to other members such as an optical member may be adversely affected. When the substrate of the release film is paper, not only the adhesive adheres during peeling, but also transferability is insufficient, and therefore, a polyester film is used in the present invention.

The polyester film as referred to in the present invention is a film obtained by stretching a sheet melt-extruded from an extrusion die by a so-called extrusion method.

The polyester constituting the film is a polymer containing an ester group obtained by polycondensation of a dicarboxylic acid and a diol or a hydroxycarboxylic acid. Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid, 2, 6-naphthalenedicarboxylic acid, and 1, 4-cyclohexanedicarboxylic acid, examples of the diol include ethylene glycol, 1, 4-butanediol, diethylene glycol, triethylene glycol, neopentyl glycol, 1, 4-cyclohexanediol, and polyethylene glycol, and examples of the hydroxycarboxylic acid include p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. As representative examples of the above-mentioned polymer, polyethylene terephthalate, polyethylene-2, 6-naphthalate and the like can be exemplified.

In the film of the present invention, it is preferable to blend particles for the main purpose of imparting slidability and preventing generation of scratches in each step. The type of particles to be blended is not particularly limited as long as they can impart slidability, and specific examples thereof include particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, alumina, and titanium oxide. Further, heat-resistant organic particles such as those described in Japanese patent publication No. 59-5216 and Japanese patent publication No. 59-217755 can be used. Examples of the other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, and benzoguanamine resins. In addition, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst in a polyester production process may be used.

On the other hand, the shape of the particles to be used is not particularly limited, and any shape such as spherical, massive, rod-like, and flat may be used. Further, the hardness, specific gravity, color, and the like are not particularly limited. The series of particles may be used in combination of 2 or more kinds as necessary.

The average particle diameter of the particles used is usually 0.01 to 3 μm, preferably 0.1 to 2 μm. When the average particle diameter is less than 0.01. mu.m, the slidability may not be sufficiently imparted. On the other hand, if it exceeds 3 μm, the transparency may be lowered due to the aggregates of the particles during film formation, and the film may be easily broken, which may cause a problem in productivity.

The content of the particles in the polyester is usually 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the content of the particles is less than 0.001 wt%, the slidability of the film may be insufficient, while when the content is more than 5 wt%, the transparency of the film may be insufficient.

The method for adding the particles to the polyester layer is not particularly limited, and conventionally known methods can be used. For example, the addition may be carried out at any stage of the production of the polyester constituting each layer, and is preferably carried out after the completion of the esterification or transesterification reaction.

Further, a method of blending a slurry of particles dispersed in ethylene glycol, water or the like with a polyester raw material by using a kneading extruder with an exhaust port; or a method of blending the dried particles with the polyester raw material using a kneading extruder.

In addition to the above particles, the polyester film of the present invention may contain, if necessary, conventionally known antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments, and the like.

The thickness of the polyester film in the present invention is not particularly limited as long as it is in a range in which the film can be formed, and is usually 10 to 350 μm, preferably 15 to 100 μm.

Next, a production example of the polyester film of the present invention will be specifically described, but the present invention is not limited to the following production example.

First, a molten sheet extruded from a die using the above-described polyester raw material is cooled and solidified by a cooling roll to obtain an unstretched sheet. In this case, in order to improve the planarity of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and it is preferable to use an electrostatic application method and/or a liquid coating method.

Next, the obtained unstretched sheet is stretched in the biaxial direction. In this case, the unstretched sheet is first stretched in one direction by a stretcher of a roll or tenter system. The stretching temperature is usually 90 to 140 ℃, preferably 95 to 120 ℃, and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Then, stretching is performed in a direction orthogonal to the stretching direction in the first stage, and in this case, the stretching temperature is usually 90 to 170 ℃, and the stretching magnification is usually 3.0 to 7 times, preferably 3.5 to 6 times.

And then, continuously performing heat treatment at the temperature of 180-270 ℃ under tension or under the relaxation within 30% to obtain the biaxially oriented film.

In the above-mentioned stretching, a method of performing 2-stage or more stretching in one direction may be employed. In this case, it is preferable to perform the stretching in both directions so that the final stretching ratios fall within the above ranges.

In addition, a simultaneous biaxial stretching method may be employed for the production of the polyester film of the present invention. The simultaneous biaxial stretching method is a method of simultaneously stretching and orienting the above-mentioned unstretched sheet in the machine direction and the width direction while controlling the temperature to usually 90 to 140 ℃, preferably 80 to 110 ℃, and the stretching magnification is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. And then, continuously carrying out heat treatment under the condition of tension or relaxation within 30% at the temperature of 170-250 ℃ to obtain the stretch oriented film. As the simultaneous biaxial stretching apparatus using the stretching method, conventionally known stretching methods such as a screw method, a pantograph method, a linear driving method, and the like can be used.

Further, a so-called coating-stretching method (in-line coating) in which the surface of the film is treated in the above-described stretching step of the polyester film may be performed. When the coating layer is provided on the polyester film by the coating-stretching method, the coating can be performed while stretching, and the thickness of the coating layer can be reduced according to the stretching ratio, whereby an appropriate film can be produced as the polyester film.

[ coating layer ]

The coating layer constituting the release film of the present invention will be explained.

The coating layer contains the conductive compound (a) and the binder polymer (B) as essential requirements.

(conductive Compound (A))

It is important for the coating layer constituting the release film of the present invention to contain the conductive compound (a) in order to improve the antistatic property and the oligomer precipitation preventing property. As the conductive compound (a), a polymer obtained by homopolymerization or copolymerization of thiophene or a thiophene derivative is preferable, and particularly, a compound formed of thiophene or a thiophene derivative doped with another anionic compound or a compound having an anionic group and self-doped with the compound exhibits excellent conductivity is suitable. Examples of the compound (a) include compounds obtained by polymerizing a compound of the following chemical formula 1 or chemical formula 2 in the presence of a polyanion.

[ chemical formula 1]

(R¹、R²Each independently represents a hydrogen element, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a cyclohexylene group, and a phenyl group. )

[ chemical formula 2]

(n is an integer of 1 to 4.)

In the mold release film of the present invention, polythiophene or a polythiophene derivative having a structural formula shown in chemical formula 2 is preferably used, and for example, a compound having n ═ 1 (methylene), n ═ 2 (ethylene), or n ═ 3 (propylene) in chemical formula 2 is preferably used. Among them, poly-3, 4-ethylenedioxythiophene, which is an ethylene compound having n-2, is particularly preferable. Examples of the polythiophene or polythiophene derivative include compounds in which a functional group is bonded to the 3-position and the 4-position of the thiophene ring. Preferred are compounds having oxygen atoms bonded to the carbon atoms at the 3-and 4-positions as described above. In addition, in the case of a compound having a structure in which a carbon atom or a hydrogen atom is directly bonded to the carbon atom, it is sometimes difficult to make the coating liquid water-borne.

As a method for producing the polymer, for example, a method shown in japanese patent application laid-open No. 7-90060 can be used.

In the release film of the present invention, the coating layer preferably contains a composition containing the polythiophene and the polyanion or a composition containing the polythiophene derivative and the polyanion.

Examples of the polyanion used for polymerization include poly (meth) acrylic acid, polymaleic acid, and polystyrene sulfonic acid. In addition, some or all of these acids may be neutralized.

A particularly preferable embodiment is a method in which a compound of formula 2 in which n is 2 is used as polythiophene and polystyrene sulfonic acid is used as polyanion.

(Binder Polymer (B))

The binder polymer (B) constituting the coating layer in the present invention is defined as: the polymer compound has a number average molecular weight (Mn) of 1000 or more as measured by Gel Permeation Chromatography (GPC) according to a safety evaluation flow chart of the polymer compound (sponsored by the society for chemical examination in Showa 60/11), and has film-forming properties.

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 mixedly dispersed in thiophene or a thiophene derivative. Examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyimides such as polyimide and polyamideimide; polyamides such as polyamide 6, polyamide 12, and polyamide 11; fluorine resins such as polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene, and the like; vinyl resins such as polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate, and polyvinyl chloride; an epoxy resin; an oxetane resin; xylene resin; an aromatic polyamide resin; polyimide silicone; a polyurethane; a polyurea; a melamine resin; a phenolic resin; a polyether; acrylic resins and copolymers thereof.

The binder polymer (B) may be dissolved in an organic solvent, or may be made into an aqueous solution by adding a functional group such as a sulfo group or a carboxyl group. The binder polymer (B) may be used in combination with a curing agent such as a crosslinking agent or a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, and the like, if necessary.

In the binder polymer (B), from the viewpoint of ease of mixing in the preparation of the coating solution, it is preferable that at least 1 kind of the binder polymer is selected from polyester resins, acrylic resins, and urethane resins. Particularly preferred is a polyurethane resin.

< polyester resin >

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

Examples of the diol component include ethylene glycol, 1, 4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1, 6-hexanediol, 1, 4-cyclohexanediol, xylylene glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, poly (ethyleneoxy) glycol, poly (tetramethyleneoxy) glycol, an alkylene oxide adduct of bisphenol a, and an alkylene oxide adduct of hydrogenated bisphenol a. These may be used in 2 or more kinds.

Among the above polyol components, ethylene glycol, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct, and 1, 4-butanediol are preferable, and ethylene glycol, an ethylene oxide adduct of bisphenol A, and a propylene oxide adduct are more preferable. In addition, in order to make aqueous liquefaction easy, the polyester resin and a few amount of sulfonate group compounds, carboxylic acid salt group compounds can be copolymerized, preferably this. Preferable examples of the compound having a sulfonate group include alkali metal sulfonate-based or amine sulfonate-based compounds such as 5-sodiosulfoisophthalic acid, 5-sulfoammonium ditoluate, 4-sodiosulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid, 2-sodiosulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 4-potassium sulfoisophthalic acid, 2-potassium sulfoisophthalic acid, and sodiosulfosuccinic acid.

Examples of the compound having a carboxylate group include trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylolpropionic acid, and the like, and mono-alkali metal salts thereof. After copolymerization, the free carboxyl group reacts with an alkali metal compound or an amine compound to form a carboxylate group. A polyester synthesized by polycondensation reaction according to a conventional method can be used, with 1 or more kinds selected as appropriate from these compounds.

The polyester resin preferably has a glass transition temperature (hereinafter, may be abbreviated as Tg) of 40 ℃ or higher, more preferably 60 ℃ or higher. When the Tg is less than 40 ℃, when the coating thickness of the coating layer is increased for the purpose of improving the adhesiveness, there may be a problem that blocking becomes easy.

< acrylic resin >

The acrylic resin is a polymer of a polymerizable monomer having a carbon-carbon double bond, such as a monomer represented by an acrylic or methacrylic monomer. They may be homopolymers or copolymers. Copolymers of these polymers with other polymers (e.g., polyesters, polyurethanes, etc.) are also included. For example, block copolymers, graft copolymers. Further, the polyester composition may contain 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. Similarly, the 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, the polymer (polymer mixture in some cases) 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, and typical examples thereof include various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid, and salts thereof; various hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxyfumarate, and monobutyl hydroxyitaconate; various (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and lauryl (meth) acrylate; various nitrogen-containing vinyl monomers such as (meth) acrylamide, diacetone acrylamide, N-methylolacrylamide, and (meth) acrylonitrile. In addition, the polymerizable monomers shown below may be copolymerized in combination with these monomers. That is, various styrene derivatives such as styrene, α -methylstyrene, divinylbenzene and vinyltoluene, and various vinyl esters such as vinyl acetate and vinyl propionate; various silicon-containing polymerizable monomers such as γ -methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, and methacryloylsilyl macromonomers; phosphorus-containing vinyl monomers; various halogenated ethylenes such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene; conjugated dienes such as butadiene.

In the acrylic resin, the glass transition temperature (hereinafter, may be abbreviated as Tg) is preferably 40 ℃ or higher, and more preferably 60 ℃ or higher. When the Tg is less than 40 ℃, when the coating thickness of the coating layer is increased for the purpose of improving the adhesiveness, there may be a problem that blocking becomes easy.

< urethane resin >

The polyurethane resin in the present invention means a polymer compound having a urethane bond in the molecule. Among them, in view of suitability for on-line coating, a water-dispersible or water-soluble urethane resin is preferable. 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 may be introduced into the urethane resin. Among the hydrophilic groups, a carboxylic acid group or a sulfonic acid group is suitably used from the viewpoint of improving the physical properties and adhesion of the coating film.

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

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

Examples of the polyester polyol 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 anhydrides thereof 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, etc.), 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, alkyldialkanolamines, lactone diol, etc.).

Examples of the polycarbonate-based polyol include polycarbonate diols obtained by dealcoholization of a polyol with dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, and the like, for example, poly (1, 6-hexylene) carbonate, poly (3-methyl-1, 5-pentylene) carbonate, and the like.

Examples of the polyisocyanate compound used for obtaining the urethane resin include aromatic diisocyanates such as toluene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, and α, α, α', aliphatic diisocyanates having an aromatic ring such as α' -tetramethylxylylene diisocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate and the like, and alicyclic diisocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl diisocyanate and the like. These may be used alone or in combination of two or more.

The chain extender may be any conventionally known chain extender used in the synthesis of urethane resins, and is not particularly limited as long as it has 2 or more reactive groups that react with isocyanate groups, and chain extenders having 2 hydroxyl groups or amino groups are commonly used.

Examples of the chain extender having 2 hydroxyl groups include aliphatic diols such as ethylene glycol, propylene glycol and butanediol, aromatic diols such as xylylene glycol and bishydroxyethoxybenzene, and diols such as ester diols such as neopentyl glycol hydroxypivalate. In addition, as a chain extender having 2 amino groups, examples thereof include aromatic diamines such as tolylenediamine, xylylenediamine and diphenylmethanediamine, aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 2-dimethyl-1, 3-propylenediamine, 2-methyl-1, 5-pentylenediamine, trimethylhexamethylenediamine, 2-butyl-2-ethyl-1, 5-pentylenediamine, 1, 8-octylenediamine, 1, 9-nonylenediamine and 1, 10-decyldiamine, and alicyclic diamines such as 1-amino-3-aminomethyl-3, 5, 5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropylidecylohexyl-4, 4' -diamine, 1, 4-diaminocyclohexane and 1, 3-bisaminomethylcyclohexane.

In the present invention, it is preferable that the coating layer constituting the release film further contains a polyurethane resin for the purpose of improving adhesiveness to the release layer.

The coating liquid for providing the coating layer in the present invention preferably further contains, as the component (C), 1 or more compounds selected from glycerol (C1), polyglycerol (C2), glycerol or an alkylene oxide adduct of polyglycerol (C3), or derivatives thereof. More preferably, the average number of glycerol units in the molecule is in the range of 2 to 20.

The alkylene oxide adduct of glycerin or polyglycerin means a compound having a structure obtained by addition polymerization of a hydroxyl group of glycerin or polyglycerin and an alkylene oxide or a derivative thereof.

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

The alkylene oxide or a derivative thereof is preferably a structure containing an ethylene oxide or propylene oxide skeleton. When the alkyl chain in the alkylene oxide structure is too long, the hydrophobicity tends to be strong, the uniform dispersibility in the coating liquid tends to be poor, and the antistatic property and transparency of the coating film tend to be poor. Ethylene oxide is particularly preferred.

In the above-mentioned alkylene oxide adduct of glycerin or polyglycerin, the copolymerization ratio of the alkylene oxide or a derivative thereof with respect to the glycerin or polyglycerin skeleton is not particularly limited, and when the glycerin or polyglycerin moiety is 1 in terms of the 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 a derivative thereof to the glycerin or the polyglycerin skeleton is larger than this range, the characteristics may become close to those in the case of using a general polyalkylene oxide, and the effects of the present invention may not be sufficiently obtained.

As a particularly preferable embodiment, the component (C) in the present invention includes polyglycerin (C2) and glycerin or an alkylene oxide adduct of polyglycerin (C3). The polyglycerol (C2) is preferably a compound of the following chemical formula 3, in which n is 2 to 20. The alkylene oxide adduct of glycerin or polyglycerin (C3) is particularly preferably a compound having a structure in which n ═ 2 in the compound of chemical formula 3 is added with ethylene oxide or polyoxyethylene, and the number of addition is particularly preferably in the range of 300 to 2000 in terms of the weight average molecular weight of the final compound (C3).

[ chemical formula 3]

The content of the component (C) in the coating layer is in the range of 10 to 90 wt%, more preferably 20 to 80 wt%. When the amount is less than 10% by weight, the coatability may be lowered. On the other hand, if the content exceeds 90% by weight, the durability of the coating layer may be insufficient.

In the present invention, the coating layer constituting the release film is preferably such that the weight of the conductive compound (A) in the coating layer is 0.5mg/m²More preferably 1mg/m or more²The above is preferable. By making the amount of the electroconductive compound (A) 0.5mg/m²Thus, sufficient antistatic properties can be obtained.

In the present invention, the ratio of the conductive compound (a) in the coating layer constituting the release film is not limited, and the upper limit is preferably 90 wt% or less, more preferably 80 wt% or less, and most preferably 60 wt% or less. When the weight ratio of the conductive compound (a) exceeds 90% by weight, the transparency of the coating layer may become insufficient or the antistatic performance may become insufficient. On the other hand, the lower limit is preferably 1% by weight or more, and more preferably 2% by weight or more. When 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, more preferably in the range of 70/30 to 1/99, and most preferably in the range of 50/50 to 2/98 in terms of weight ratio. If the amount is outside this range, antistatic performance and appearance of the coating film tend to be deteriorated.

The coating liquid used in the present invention may contain additives such as an antifoaming agent, a coatability improver, a thickener, an organic lubricant, a release agent, organic particles, inorganic particles, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, and a pigment. These additives may be used alone, or two or more of them may be used in combination as required.

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, and may contain an organic solvent as long as the aqueous solution is used as a main medium and the range of the aqueous solution does not exceed the gist of the present invention.

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

[ Silicone Release layer ]

The silicone-based release layer was formed using the following release agent composition. The mold release composition in the present embodiment contains 1 st polydimethylsiloxane having at least 1 alkenyl group in the molecule and 1 st polydimethylsiloxane having at least 1 hydrosilyl group in the molecule as the addition reaction type silicone resin.

Examples of the alkenyl group contained in the 1 st polydimethylsiloxane used in the present invention include 1-valent hydrocarbon groups 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, and among them, a vinyl group and a hexenyl group are preferable.

The alkenyl group (a) preferably contains 3 to 90mmol, more preferably 6 to 45mmol, in 30g of the 1 st polydimethylsiloxane. Further, the hydrosilyl group (b) is preferably contained in an amount of 6 to 450mmol, more preferably 15 to 450mmol, in 30g of the 2 nd polydimethylsiloxane. 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 1 st polydimethylsiloxane must be 500 or more and 30000 or less, preferably 1000 or more and 20000 or less, and particularly preferably 2000 or more and 10000 or less. When the weight average molecular weight of the 1 st polydimethylsiloxane is less than 500, the reactivity is high and the reaction proceeds in the mixed liquid, and therefore, a desired light peeling force is not expressed, and when it exceeds 30000, the reactivity is deteriorated and the desired light peeling force is not expressed.

The content of the 1 st polydimethylsiloxane in the mold release composition is preferably 40 to 90% by weight, more preferably 50 to 80% by weight.

The weight average molecular weight of the 2 nd polydimethylsiloxane must be 120 or more and 10000 or less, preferably 150 or more and 5000 or less, and particularly preferably 200 or more and 2000 or less. When the weight average molecular weight of the 2 nd polydimethylsiloxane is less than 120, the reactivity is high and the reaction proceeds in the mixed liquid, and therefore, a desired light peeling force is not expressed, and when it exceeds 10000, the reactivity is deteriorated and the desired light peeling force is not expressed. The weight average molecular weight in the present invention is a value in terms of polystyrene measured by a Gel Permeation Chromatography (GPC) method.

The content of the 2 nd polydimethylsiloxane in the mold release 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 reaction of addition molding is used in order to make the silicone-based release layer clean and strong. Examples of the present component include platinum compounds such as chloroplatinic acid, alcohol solutions of chloroplatinic acid, complexes of chloroplatinic acid with olefins, and complexes of chloroplatinic acid with alkenylsiloxane, platinum black, platinum-supported silica, and platinum-supported activated carbon. The content of the platinum-based catalyst in the silicone-based release layer is preferably in the range of usually 0.3 to 3.0 wt%, preferably 0.5 to 2.0 wt%. When the platinum-based catalyst content in the silicone-based release layer is less than 0.3 wt%, defects such as a peeling force and a surface state deterioration due to insufficient curing reaction of the coating layer may occur, while when the platinum-based catalyst content in the silicone-based release layer exceeds 3.0 wt%, process defects such as a cost increase, an increase in reactivity, and the generation of gel foreign matter may occur.

By forming the silicone-based release layer using the release agent composition satisfying the above conditions, the light-peeling release film can be peeled extremely smoothly when the light-peeling release film is peeled from the adhesive layer in the use of the substrate-less double-sided adhesive sheet.

In the release agent composition of the present invention, an unreacted organopolysiloxane, which is one of unreacted silicone resins, may be added to impart a light releasability. The weight average molecular weight of the unreacted organopolysiloxane is preferably 50000 or more and 500000 or less.

The unreacted silicone resin is preferably an organopolysiloxane represented by the following general formula (I).

R₃SiO(R₂SiO)_mSiR₃……(I)

(wherein R represents a monovalent hydrocarbon group of the same or different species having no aliphatic unsaturated bond, and m represents a positive integer.)

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

In order to reduce the peeling force in the present invention, silicone oil may be added. The silicone oil is referred to as a pure silicone oil or a modified silicone oil, and the following can be mentioned. Examples of the pure silicone include dimethyl silicone oil, methylphenyl silicone oil, and methylhydrogen silicone oil. Examples of the modified silicone oil include 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, phenyl modification, both-terminal type polyether modification, polyether/methoxy modification, and the like.

The silicone oil component of the mold release composition of the present invention 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 less than 1 wt%, the speed dependence of the peeling force may become high, and if it exceeds 5 wt%, the transferability may be high, and the roller may be contaminated during the pressure-sensitive adhesive processing, and the adhesive peeling force may be reduced by transferring to the pressure-sensitive adhesive surface.

In addition, as the release agent composition used in the present invention, an addition reaction type silicone resin is preferably used. In addition reaction type, since the reactivity is very high, acetylene alcohol may be added as a reaction inhibitor in some cases. The component (A) is an organic compound having a carbon-carbon triple bond and a hydroxyl group, and is preferably a compound selected from the group consisting of 3-methyl-1-butyn-3-ol, 3, 5-dimethyl-1-hexyn-3-ol, and phenylbutynol.

The method for forming the silicone-based release layer on at least one surface of the polyester film is not particularly limited, and a method of applying a release agent composition (coating liquid) in a step of producing the polyester film can be suitably employed. Specifically, there may be mentioned: a method of applying and drying a coating liquid to the surface of an unstretched sheet, a method of applying and drying a coating liquid to the surface of a uniaxially stretched film, a method of applying and drying a coating liquid to the surface of a biaxially stretched film, and the like. Among these, a method of simultaneously drying and curing the silicone-based release layer in the course of heat-treating the film after coating the coating liquid on the surface of the unstretched film or uniaxially stretched film is economical.

As a method for forming the silicone-based release layer, a method in which some of the above-described coating methods are used in combination may be employed as necessary. Specifically, there may be mentioned a method in which a first layer is applied to the surface of an unstretched sheet and dried, then the sheet is uniaxially stretched, and then a second layer is applied and dried. As a method for applying the coating liquid to the surface of the polyester film, a reverse roll coater, a gravure coater, a bar coater, an air knife coater, a bar coater, and a knife coater, which are described in original nakayaura, a study on Maki, and published 1979.

The amount of the silicone-based release layer to be applied in the present invention is preferably 0.01 to 1g/m²More preferably 0.15 to 0.70g/m²。

In the present invention, a coating layer such as an adhesive layer, an antistatic layer, and an oligomer deposition preventing layer may be provided on the surface where the silicone-based release layer is not provided, or between the polyester film and the silicone-based release layer, and the polyester film may be subjected to surface treatment such as corona treatment or plasma treatment.

In the present invention, the residual adhesion ratio of the tape (No. 31B tape, manufactured by ritong electrical corporation) is preferably 80% or more, and more preferably 85% or more. If the residual adhesion rate is less than 80%, transferability is high, and roll contamination occurs during adhesive processing, and transfer to the adhesive surface occurs, resulting in a decrease in adhesive release force.

In the present invention, the silicone release layer surface peeling force of the pressure-sensitive adhesive tape (tesa 7475 manufactured by tesa corporation) at 300mm/min is preferably 9g/25mm or less, more preferably 8g/25mm or less. When the peel force exceeds 9g/25mm, the release film may not be cleanly peeled from the pressure-sensitive adhesive when the release film is used for protecting the pressure-sensitive adhesive layer. On the other hand, the lower limit of the peeling force is not particularly limited, but is more preferably 1g/25mm or more, and still more preferably 3g/25mm or more.

Further, the higher the peeling speed is, the higher the peeling force tends to be, and if the peeling speed is increased, there may be a problem that peeling does not occur cleanly.

In the present invention, the peel force of the adhesive tape (tesa 7475 manufactured by tesa) at 30 m/min is preferably 250g/25mm or less, more preferably 200g/25mm or less. When the release film is used for the pressure-sensitive adhesive layer protection, the release film can be easily and cleanly released from the pressure-sensitive adhesive by setting the release force to 250g/25mm or less, 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 is more preferably 10g/25mm or more, and still more preferably 25g/25mm or more.

The peel force in the present invention is a value measured by a tensile tester when a tape (tesa 7475 manufactured by tesa corporation) is attached to a silicone-based release layer surface and left at room temperature for 1 hour, and then the tape is peeled at a peel angle of 180 ° from a polyester film and at a specific tensile speed (peel speed). The method of adjusting the specific peeling force in the present invention can be achieved by selecting the composition in the silicone-based release layer, but other methods can be employed, and it is preferable to change the type of release agent of the silicone release layer mainly in accordance with the desired peeling force, and further preferable to adjust the amount of application of the release agent composition because the peeling force greatly depends on the amount of application of the release agent composition used.

[ adhesive layer ]

The release film of the present invention is suitable for application to an adhesive layer.

The adhesive composition used in the adhesive layer is not particularly limited, and specific examples thereof include silicone adhesives, acrylic adhesives, urethane adhesives, and epoxy adhesives. Among these, acrylic adhesives are preferable, and acrylic solvent adhesives are more preferable, from the viewpoint of wide adjustment range of adhesive properties and general-purpose use.

Additives such as stabilizers, curing agents, tackifiers, fillers, colorants, antioxidants, antistatic agents, and surfactants may be used as necessary in the adhesive composition within the range not to impair the gist of the present invention.

The solvent used in the pressure-sensitive adhesive composition is not particularly limited, and a solvent capable of dissolving or dispersing uniformly and stably is preferably used to a moderate degree. Examples of the solvent include alcohols (methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, benzyl alcohol, PGME, ethylene glycol, diacetone alcohol); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, heptanone, diisobutyl ketone, diethyl ketone, diacetone alcohol); esters (methyl acetate, ethyl acetate, butyl acetate, n-propyl acetate, isopropyl acetate, methyl formate, PGMEA); aliphatic hydrocarbons (hexane, cyclohexane); halogenated hydrocarbons (dichloromethane, chloroform, carbon tetrachloride); aromatic hydrocarbons (benzene, toluene, xylene); amides (dimethylformamide, dimethylacetamide, N-methylpyrrolidone); ethers (diethyl ether, dioxane, tetrahydrofuran); ether alcohols (1-methoxy-2-propanol); and carbonates (dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate) and the like. These solvents may be used alone, or 2 or more of them may be used in combination.

Examples

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

(1) Measurement of average particle diameter (d 50: μm):

the cumulative (weight basis) value in the spherical equivalent distribution measured by a centrifugal sedimentation type particle size distribution measuring apparatus (model SA-CP3, manufactured by Shimadzu corporation) was 50% as the average particle diameter.

(2) Evaluation of peeling force of release film:

after one surface of an adhesive tape ("tesa 7475" manufactured by tesa corporation) was attached to the surface of the silicone-based release layer of the sample film, the peel force after leaving at room temperature for 1 hour was measured. For the peeling force, 180 ° peeling was performed using a tensile tester (Intesco co., ltd. "Intesco Model 2001 Model") at a tensile speed of 300 mm/min. The evaluation results are shown in tables 2A and 3B.

(3) Transfer property of release film was evaluated (residual adhesion ratio):

the sample film was cut to a size of a4, an adhesive tape (No. 31B, manufactured by ritonado electric corporation) was attached to the measurement surface of the film using a rubber roll, and after 1 hour, the adhesive tape was peeled off, and the adhesive tape was attached to a stainless steel plate whose surface was cleaned using a rubber roll. The adhesive tape was fixed to the upper chuck and the stainless steel plate was fixed to the lower chuck, and the sheets were peeled off at a speed of 300mm/min in the 180 ° direction to measure the adhesion (I).

The adhesive force (II) was measured by the same procedure as described above using an adhesive tape (No. 31B, Nindon electric Co., Ltd.) which did not adhere to the sample. The residual adhesion ratio was obtained by the following equation. The evaluation results are shown in tables 2A and 3B.

Residual adhesion ratio (%) { adhesion (I)/adhesion (II) } × 100

(4) Surface inherent resistance of release film

The surface resistivity of the surface of the release layer of the sample film was measured by the following method (4-1). Since the method using (4-1) cannot measure more than 1X 10⁸Since omega has a surface intrinsic resistance, the method of (4-2) was used for a sample that could not be measured by (4-1). The evaluation results are shown in Table 3B.

Measurement method

(4-1) production of Low resistivity Meter by Mitsubishi chemical: LORESTA GPMCP-T600 was subjected to humidity conditioning at 23 ℃ and 50% RH in a measurement atmosphere for 30 minutes, and then the surface resistivity was measured.

(4-2) manufacturing a high resistance meter using Hewlett-Packard Japan, Ltd.: HP4339B and measurement electrode: HP16008B was measured for the surface resistivity value after conditioning the sample at 23 ℃ for 30 minutes in a measuring atmosphere at 50% RH.

Reference to evaluation

Very good: r (omega) is 1X 10⁸The following (practical, particularly good)

O: r (omega) is 1X 10⁹The following (practical use)

And (delta): r (omega) is 1X 10¹⁰The following (which may cause problems in practical use)

X: r (omega) exceeds 1 x 10¹⁰(difficulty in practical use)

(5) Evaluation of coating film adhesion of Release film (evaluation of substitution of actual use Properties)

The sample film was left in a constant temperature and humidity bath at 60 ℃ and 80% RH for 4 weeks, and then the sample film was taken out. Then, the release surface of the sample film was rubbed 5 times by hand contact, and the degree of release of the release layer was evaluated according to the following evaluation criteria.

Reference to evaluation

O: no peeling of the coating film was observed (practical use, particularly good)

And (delta): the coating film turns white but does not fall off (can be used practically)

X: the peeling of the coating film was confirmed (difficulty in practical use)

(6) Mold release characteristics (actual use instead of evaluation):

an acrylic pressure-sensitive adhesive composition having the following composition was applied to a release film, and then heat-treated at 100 ℃ for 5 minutes to obtain a pressure-sensitive adhesive having a thickness of 200 μm after drying. Then, the release film and the adhesive-bonded product were stored at room temperature for 1 week, and then the release film was peeled off, and the release characteristics were evaluated according to the following evaluation criteria, depending on the state when the release film was peeled off from the adhesive. The evaluation results are shown in tables 2A and 3B.

Acrylic adhesive composition

A main agent: 100 parts by weight of AT352(SAIDEN CHEMICAL INDUSTRY CO., LTD., manufactured by LTD.)

Curing agent: 0.25 part by weight of AL (SAIDEN CHEMICAL INDUSTRY CO., LTD., manufactured by LTD.)

Additive: 0.25 part by weight of X-301-375SK (SAIDEN CHEMICAL INDUSTRY CO., LTD., manufactured by

Additive: 0.4 part by weight of X-301-352S (SAIDEN CHEMICAL INDUSTRY CO., LTD., manufactured by LTD.)

Toluene: 40 parts by weight of

Reference to evaluation

O: the release film was cleanly peeled off, and no adhesive was observed adhering to the silicone release layer.

And (delta): the release film was peeled off, but the adhesive was adhered to the silicone-based release layer when peeled off at a high speed.

X: the adhesive was attached to the release film and could not be smoothly peeled off.

The polyesters used in the examples and comparative examples were prepared as follows.

< production of polyester >

100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol were used as starting materials, 0.09 part by weight of magnesium acetate/tetrahydrate salt as a catalyst was charged into a reactor, the reaction initiation temperature was 150 ℃ and the reaction temperature was gradually raised while removing methanol by distillation and was 230 ℃ after 3 hours. The transesterification reaction was substantially terminated after 4 hours. To the reaction mixture, 0.04 parts by weight of ethyl acid phosphate was added, and then 0.06 part by weight of silica particles having an average particle diameter of 1.6 μm and dispersed in ethylene glycol and 0.04 part by weight of antimony trioxide were added to conduct polycondensation reaction for 4 hours. That is, the temperature was slowly raised from 230 ℃ to 280 ℃. On the other hand, the pressure was gradually decreased from the normal pressure to 0.3mmHg finally. After the reaction was started, the reaction was stopped at the time of 4 hours, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the resulting polyester was 0.53 dl/g.

< production of Release film >

Examples 1A to 4A and comparative examples 1A to 6A below are illustrative of the 1 st invention, and examples 1B to 4B and comparative examples 1B to 6B below are illustrative of the 2 nd invention.

[ example 1A ]

The polyester (1) as described above was supplied to an extruder with vent holes as a raw material, melt-extruded at 290 ℃ and then cooled and solidified on a cooling roll having a surface temperature of 40 ℃ by an electrostatic charge method to obtain an amorphous film having a thickness of about 550 μm.

The film was stretched 3.7 times in the longitudinal direction at 85 ℃ and 3.9 times in the transverse direction at 100 ℃ and heat-treated at 210 ℃ to obtain a 38 μm thick biaxially stretched polyester film.

The release agent composition shown below was coated in an amount (after drying) of 0.200g/m by reverse gravure coating²The above-mentioned coating was applied to the obtained polyester film, and a release film was obtained in a roll form under the conditions of a dryer temperature of 150 ℃ and a linear velocity of 30 m/min. The evaluation results of the release film are shown in table 2A.

Further, the release film obtained in example 1A was peeled at 180 ℃ at a stretching speed of 30 m/min, resulting in a peel force of 108g/25 mm. The same procedure as in (2) was carried out except that the stretching speed was changed to 30 m/min for the conditions relating to the peeling force.

< mold Release agent composition >

A vinyl-modified silicone resin (weight average molecular weight: 2000) having at least 2 vinyl groups in the structure of polydimethylsiloxane 1 as the 1 st polydimethylsiloxane and a polymethylhydrosiloxane (weight average molecular weight: 200) having at least 2 hydrosilyl groups in the structure of polydimethylsiloxane 2 as the 2 nd polydimethylsiloxane were mixed so as to be 77/22 st polydimethylsiloxane/2 nd polydimethylsiloxane, diluted with a solvent having a compounding ratio of toluene/MEK/hexane 1/1/18 so that the solid content became 3 wt%, and then 2 parts by weight of a platinum-based catalyst (SRX-212 manufactured by Dow Corning ay co., ltd.) was added to obtain a mold release agent composition.

The parts by weight of the platinum-based catalyst are values when the total parts of the 1 st polydimethylsiloxane and the 2 nd polydimethylsiloxane is 100.

Examples 2A to 4A and comparative examples 1A to 6A

A silicone-based release film was produced in the same manner as in example 1A, except that the release agent composition shown in table 1A was changed to the release agent composition, and a release film was obtained. The evaluation results of the release film are shown in table 2A.

< raw Material for mold Release agent composition >

a 1: vinyl-modified silicone resin having at least 2 vinyl groups in the structure of polydimethylsiloxane (weight-average molecular weight: 2000)

a 2: vinyl-modified silicone resin having at least 2 vinyl groups in the structure of polydimethylsiloxane (weight-average molecular weight: 20000)

a 3: vinyl-modified silicone resin having at least 2 vinyl groups in the structure of polydimethylsiloxane (weight-average molecular weight: 1000)

a 4: vinyl-modified silicone resin having at least 2 vinyl groups in the structure of polydimethylsiloxane (weight-average molecular weight: 60000)

a 5: vinyl-modified silicone resin having at least 2 vinyl groups in the structure of polydimethylsiloxane (weight-average molecular weight: 300)

b 1: polymethylhydrosiloxane having at least 2 hydrosilyl groups in the structure of polydimethylsiloxane (weight-average molecular weight: 200)

b 2: polymethylhydrosiloxane having at least 1 hydrosilyl group in the structure of polydimethylsiloxane (weight-average molecular weight: 5000)

b 3: polymethylhydrosiloxane having at least 1 hydrosilyl group in the structure of polydimethylsiloxane (weight-average molecular weight: 30000)

b 4: polymethylhydrosiloxane having at least 2 hydrosilyl groups in the structure of polydimethylsiloxane (weight-average molecular weight: 100)

c 1: platinum catalyst (SRX-212 manufactured by Dow Corning Toray Co., Ltd.)

Further, the release film obtained in example 4A was peeled at 180 ℃ at a stretching speed of 30 m/min, resulting in a peel force of 112g/25 mm. The same procedure as in (2) was carried out except that the stretching speed was changed to 30 m/min for the conditions relating to the peeling force.

[ Table 1A ]

[ comparative example 7A ]

The biaxially stretched polyester film obtained in example 1A was not coated with a release agent composition, and a polyester film having no silicone release layer was used as a release film. The evaluation results of the release film are shown in table 2A.

[ Table 2A ]

	Release layer	Peeling force [ g/25mm ]]	Residual adhesion [% ]]	Mold release characteristics
					Example 1A	Release layer 1	6	95	○
Example 2A	Release layer 2	7	87	○
					Example 3A	Release layer 3	7	85	○
Example 4A	Release layer 4	8	90	○
					Comparative example 1A	Release layer 5	13	90	×
Comparative example 2A	Release layer 6	15	87	×
					Comparative example 3A	Release layer 7	17	87	×
Comparative example 4A	Release layer 8	14	87	×
					Comparative example 5A	Release layer 9	Not peeled off	35	×
Comparative example 6A	Release layer 10	Not peeled off	35	×
					Comparative example 7A	Without release layer	Not peeled off	100	×

[ example 1B ]

The film was stretched 3.7 times in the machine direction at 85 ℃ to give a coating layer comprising the following coating agent composition in a thickness (after drying) of 0.03g/m²After the coating, the polyester film was stretched 3.9 times in the transverse direction at 100 ℃ and heat-treated at 210 ℃ to obtain a 38 μm thick biaxially stretched polyester film.

< coating agent composition >

A: baytron PAG, manufactured by STARCK corporation, containing polyethylenedioxythiophene and polystyrenesulfonic acid

B: polyurethane resin

A polyester polyol was obtained which was composed 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. Then, 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 polyester polyol A having a pendant carboxyl group. Further, 160 parts by weight of hexamethylene diisocyanate was added to 1880 parts by weight of the polyester polyol a to obtain a polyurethane coating agent composition.

C: glycerol having n-1 in the above formula (3)

The weight ratio of the components is as follows: A/B/C40/40/20 (wt%)

The above-mentioned mold release composition used in the description of the invention 1 was coated in an amount (after drying) of 0.200g/m by reverse gravure coating²The above-mentioned coating liquid was applied to the obtained polyester film to obtain a roll-like polyester film at a dryer temperature of 150 ℃ and a linear velocity of 30 m/minAnd (5) demolding the film.

Examples 2B to 5B and comparative examples 1B to 10B

A release film was produced in the same manner as in example 1B, except that the coating layer and the release layer were changed to the coating agent composition and the release agent composition shown in tables 1B and 2B.

[ Table lB ]

< coating agent composition >

[ Table 2B ]

Comparative example 10B

A polyester film having no release layer was used as a release film without applying a release agent to the biaxially stretched polyester film obtained in example 1.

[ Table 3B ]

Claims

1. A release film comprising a polyester film and, formed on at least one surface thereof, a silicone-based release layer formed from a release agent composition comprising: a1 st polydimethylsiloxane having a weight-average molecular weight of 500 or more and 30000 or less and having at least 1 alkenyl group in 1 molecule; a2 nd polydimethylsiloxane having a weight-average molecular weight of 150 to 10000 inclusive and having at least 1 hydrosilyl group in 1 molecule; and a platinum-group catalyst, and a catalyst,

in the mold release composition, the content of the 1 st polydimethylsiloxane is 40 to 80% by weight, the content of the 2 nd polydimethylsiloxane is 20 to 60% by weight, and the total content of the components in the mold release composition is 100% by weight.

2. A release film comprising a polyester film and, sequentially provided on at least one surface thereof, a coating layer containing a conductive compound (A) and a binder polymer (B), and a release layer which is a silicone-based release layer formed from a release agent composition comprising: a1 st polydimethylsiloxane having a weight-average molecular weight of 500 or more and 30000 or less and having at least 1 alkenyl group in 1 molecule; a2 nd polydimethylsiloxane having a weight-average molecular weight of 150 to 10000 inclusive and having at least 1 hydrosilyl group in 1 molecule; and a platinum-group catalyst, and a catalyst,

3. The release film according to claim 1 or 2, wherein a peeling force between the surface of the silicone-based release layer and the adhesive tape at a peeling speed of 300mm/min is 9g/25mm or less.