WO2019059329A1

WO2019059329A1 - Mold release film and laminate

Info

Publication number: WO2019059329A1
Application number: PCT/JP2018/034953
Authority: WO
Inventors: 俊啓開
Original assignee: 三菱ケミカル株式会社
Priority date: 2017-09-21
Filing date: 2018-09-21
Publication date: 2019-03-28
Also published as: KR102535755B1; CN111051061B; JPWO2019059329A1; KR20200056997A; JP7234929B2; CN111051061A; TW201920561A; TWI778135B

Abstract

A mold release film which comprises a crosslinkable resin layer at least on one surface of a polyester film, said polyester film having been stretched at least in one axial direction, and a mold release layer further laminated on the crosslinkable resin layer, wherein: the crosslinkable resin layer is formed of a crosslinkable resin composition comprising a cationic group-containing ionic polymer (A) and a crosslinking agent (C); the mold release layer is formed of a mold releasing agent composition comprising a first polydimethylsiloxane having a weight-average molecular weight of 500-50000 and having at least one alkenyl group per molecule and a second polydimethylsiloxane having a weight-average molecular weight of 120-20000 and having at least one hydrosilyl group per molecule; and the peel force measured by the following method is not more than 4 g/25 mm. <Measurement of peel force> The mold release layer of the mold release film is bonded to an adhesive tape ("No. 502" manufactured by Nitto Denko Co., acrylic adhesive) and subjected to 180° peel test at a tension rate of 300 mm/min.

Description

Release film and laminate

The present invention relates to a release film and a laminate.

A polyester film-based release film is conventionally used for various optical applications, and is used to bond optical members such as a polarizing plate and a retardation plate via an adhesive layer. It has For example, various display components can be manufactured, such as a capacitive touch panel, a liquid crystal display component, a plasma display panel component, and an organic electroluminescence (organic EL) component.
In recent years, when bonding a substrateless double-sided pressure-sensitive adhesive sheet for manufacturing a touch panel, which is one of optical members, and a release film, many problems due to the peeling force of the release film have been reported.

The substrate-less double-sided pressure-sensitive adhesive sheet has a laminate structure in which a light release film having a relatively low peel force and a heavy release film having a relatively high peel force are laminated on both sides of the pressure-sensitive adhesive layer. It is a double-sided adhesive sheet which becomes only the adhesive layer which does not have a support base material after removing.

As a method of using the substrate-less double-sided pressure-sensitive adhesive sheet, first, the light release film is peeled off, one surface of the exposed pressure-sensitive adhesive layer is bonded to the opposite object surface to be bonded, The other side of the exposed adhesive layer is bonded to a different object surface, thereby exemplifying a processing step in which the objects are surface-bonded.

In recent years, the substrate-less double-sided pressure-sensitive adhesive sheet attracts attention for its good workability, and its use is expanding, and is also used for members for various optical applications such as mobile phones. In particular, a capacitive touch panel is in a situation where the use as an information terminal is rapidly expanding due to a multi-touch operation in which a screen operation is performed by two fingers. Since the capacitive touch panel tends to have a thicker printing step than the resistive film method, it has been proposed to thicken the adhesive layer to eliminate the printing step. When the pressure-sensitive adhesive layer is thickened, when the release film is peeled off, a part of the pressure-sensitive adhesive layer may adhere to the release film, or air bubbles may be mixed in the pressure-sensitive adhesive layer. Therefore, when using a substrateless double-sided pressure-sensitive adhesive sheet for optical applications, not only the substrateless double-sided pressure-sensitive adhesive sheet but also the combined release film is more severe than before and release films of higher quality It is in the necessary situation.

When using a substrate-less double-sided pressure-sensitive adhesive sheet, a light-peelable release film that is relatively easy to peel may be used, but when peeling the light-peelable release film from the pressure-sensitive adhesive layer, it is higher than the desired peel strength. It is a problem that the yield is reduced because the adhesive can not be peeled off well. For this reason, a lighter release film is required to be lighter than before.

On the other hand, a release film based on a polyester film has a problem that it is easily charged due to its properties, and in industrial use, for example, the following problems may occur. 1: The release film is generally used in such a manner that it is peeled off after being bonded to another member through the pressure-sensitive adhesive layer. However, since the release film is easily charged, charging occurs at the time of peeling. At this time, the peeling charge damages the member which is the adherend or attracts the surrounding dust to cause a defect. 2: In the substrate-less double-sided pressure-sensitive adhesive sheet having a configuration in which the pressure-sensitive adhesive layer is sandwiched between two release films, one release film is peeled off and bonded to another member. If dust is attached to the adhesive surface by peeling charge at this time and is bonded to another member, the dust is trapped between the members, so that peeling can not be performed, resulting in a product having a defect. Therefore, it is not always sufficient to use only the antistatic measures by means of equipment in the manufacturing process, and there is a strong demand for antistatic treatment from the release film itself.

As a solution to this problem, there has been proposed an antistatic layer containing a π electron conjugated conductive polymer (see, for example, Patent Documents 1 and 2).
In addition, a release film having a silicone resin coating film on an antistatic layer containing an ionic polymer has been proposed, and the antistatic performance and productivity have been improved (see, for example, Patent Document 3).

JP, 2012-183811, A JP 2012-993 A JP 2007-45953 A

However, while the antistatic films of Patent Documents 1 and 2 have good antistatic properties, when melt recycling of the antistatic film is performed, the phase of the polyester constituting the substrate and the phase of the conductive polymer constituting the antistatic layer Since the solubility is so low that foreign substances are generated, there is a problem that the productivity can not be reduced because the recycling can not be performed. In addition, the release film of Patent Document 3 not only has a heavy release force between the releasable silicone resin coating film forming the release layer of the release film and the adhesive layer of the adherend, but also constitutes the release film. The adhesion between the antistatic layer and the releasable silicone resin coating film (releasing layer) with time was insufficient.

Therefore, in the present invention, the releasability (light releasability) between the releasable silicone resin coating film constituting the releasable layer of the releasable film and the adhesive layer of the adherend, and the releasable layer surface of the releasable film Anti-static properties of the release film, adhesion between the cross-linked resin layer (anti-static layer) constituting the release film and the release layer with time, and being melt recyclable and having good productivity It provides a film.

The present inventor has found that the above-mentioned problems can be solved by using the polyester film substrate, the specific crosslinked resin layer, and the specific releasing layer as a result of earnestly examining the above-mentioned problems. We came to complete the invention.
That is, the present invention is as follows.

The present invention is a release film having a crosslinked resin layer on at least one surface of a polyester film stretched in at least uniaxial direction, and further having a release layer laminated on the crosslinked resin layer,
The crosslinked resin layer is formed of a crosslinked resin composition containing an ionic polymer (A) having a cationic group and a crosslinking agent (C),
The release layer has a weight average molecular weight of 500 to 50,000, and a first polydimethylsiloxane having at least one alkenyl group in one molecule, and a weight average molecular weight of 120 to 20,000, in one molecule. Formed from a release agent composition containing a second polydimethylsiloxane having at least one hydrosilyl group, and
A release film having a peel strength of 4 g / 25 mm or less when measured by the following method is provided.
<Measurement of Peeling Force> A release layer of a release film and a pressure-sensitive adhesive tape (Nitto Denko Co., Ltd., “No. 502, acrylic adhesive) are attached to each other, and the tensile speed is 300 mm / min. Conduct a 180 ° peel test.

The present invention further comprises a release film having a crosslinked resin layer on at least one surface of a polyester film stretched in at least one uniaxial direction, and further having a release layer laminated on the crosslinked resin layer, and a double-sided adhesive sheet It is a laminated body laminated,
The crosslinked resin layer contains an ionic polymer (A) having a cationic group,
The release layer contains polydimethylsiloxane and has a film thickness of 0.01 to 1 μm,
There is provided a laminate in which the peeling force between the surface of the release layer of the release film and the double-sided pressure-sensitive adhesive sheet is 4 g / 25 mm or less at 180 ° peeling under the conditions of a tensile speed of 300 mm / min.

According to the present invention, the releasability (light releasability) between the releasable silicone resin coating film constituting the releasable layer of the releasable film and the adhesive layer of the adherend, and the releasable layer of the releasable film Provided is a release film having good antistatic properties on the surface, adhesion between a crosslinked resin layer constituting the release film and the release layer with time, and being melt recyclable and having good productivity. be able to.

<Release film>
The release film of the present invention has a crosslinked resin layer on at least one surface of a polyester film stretched at least in a uniaxial direction, and further, a release layer is laminated on the crosslinked resin layer.

[Polyester film]
The polyester film in the present invention is a film obtained by stretching a sheet melt-extruded from an extrusion die according to a so-called extrusion method at least uniaxially.
The polyester layer constituting the polyester film may have a single-layer structure or a multi-layer structure, and in addition to the two-layer or three-layer structure, four or more layers may be used as long as the gist of the present invention is not exceeded. It may be present and is not particularly limited. Moreover, each polyester layer may use together the following polyester 1 type or 2 types or more.

<polyester>
The polyester used for the polyester layer is preferably a homopolyester composed of one kind of aromatic dicarboxylic acid and one kind of aliphatic glycol obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. It may be a copolyester obtained by copolymerizing one or more other components.

When it consists of homo polyesters, terephthalic acid, 2, 6- naphthalene dicarboxylic acid etc. are mentioned as aromatic dicarboxylic acid, ethylene glycol, diethylene glycol, 1, 4- cyclohexane dimethanol etc. are mentioned as aliphatic glycol . A polyethylene terephthalate etc. are mentioned as a typical polyester.

On the other hand, examples of the dicarboxylic acid used as a component of the copolymerized polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid and the like.
Examples of the glycol component include ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like.
Furthermore, polyesters obtained by copolymerizing other acid components and glycol components may be used.

In addition, the polyester film contains an oligomer in the outermost layer of the multilayer structure film in order to reduce the amount of precipitation and crystallization of the oligomer contained in the release film on the surface due to the heat history during film processing and the like. It is also possible to use reduced amounts of polyester. As a method of reducing the amount of oligomers in the polyester, for example, a solid phase polymerization method can be used.

There is no restriction | limiting in particular as a polymerization catalyst of polyester, A conventionally well-known compound can be used. For example, antimony compounds, titanium compounds, germanium compounds, manganese compounds, aluminum compounds, magnesium compounds, calcium compounds and the like can be mentioned. The polymerization catalyst may be used alone or in combination of two or more.

<particle>
The polyester film can contain particles mainly for the purpose of imparting slipperiness, ensuring the film traveling property in each step, and preventing the occurrence of flaws. The type of particles to be blended is not particularly limited as long as the particles can be provided with slipperiness. For example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, calcium phosphate, calcium fluoride, calcium oxalate, lithium fluoride, zeolite, magnesium phosphate, kaolin, talc, aluminum oxide, alumina, titanium oxide And particles of molybdenum sulfide and the like. Among these, it is preferable to use a silica particle from the viewpoint of imparting slipperiness.

Further, heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755, etc. may be used. Examples of the other heat resistant organic particles include thermosetting urea resin, thermosetting phenol resin, thermosetting epoxy resin, benzoguanamine resin and the like. Furthermore, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can also be used in the polyester production process.
These particles may be used alone or in combination of two or more.
On the other hand, the shape of the particles to be used is not particularly limited either, and any of spherical, massive, rod-like, flat and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc.

The particle size of the particles may be selected according to the application and purpose of the film, but is preferably 0.01 to 5 μm, more preferably 0.01 to 2 μm. If the average particle size is 0.01 μm or more, there is little risk of aggregation of the particles and sufficient dispersibility is obtained. If the average particle size is 5 μm or less, the surface roughness of the film does not become too rough, There is no risk of problems occurring when providing a mold layer.

Furthermore, the particle content in the polyester film is preferably 0.001 to 5% by mass, more preferably 0.005 to 3% by mass. If the particle content is 0.001% by mass or more, sufficient lubricity is obtained in the polyester film, and if 5% by mass or less, the transparency of the polyester film is maintained.

If there are no particles, or if there are few particles, the transparency of the film will be high and it will be a good film, but handling may become difficult as slipperiness becomes insufficient, so the particles are put in knurling or crosslinked resin layer Ingenuity such as may be necessary.

It does not specifically limit as method to add particle | grains in polyester, A conventionally well-known method can be employ | adopted. For example, although it can be added at any stage of producing the polyester constituting each layer, preferably, after completion of the esterification or transesterification reaction, particles may be added to proceed with the polycondensation reaction.
Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a polyester raw material using a vented kneading extruder, or blending of dried particles with a polyester raw material using a kneading extruder It is done by the method etc.

<Other ingredients>
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, as required.

<Production method of polyester film>
Although the manufacturing method of a biaxially stretched film is concretely demonstrated as a manufacturing example of a polyester film, it is not limited at all to the following manufacturing example, The film forming method of the polyester film generally known can be employ | adopted.
First, it is preferable to use the above-described polyester raw material and cool and solidify the molten sheet extruded from the die with 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 an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed.
Next, the obtained unstretched sheet is biaxially stretched. In that case, first, the unstretched sheet is stretched in one direction by a roll or tenter-type stretching machine. The stretching temperature is usually about 70 to 145 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually about 2.5 to 7 times, preferably 3.0 to 6 times. Next, the film is stretched in the direction orthogonal to the first-stage stretching direction, in which case the stretching temperature is usually about 70 to 170 ° C., and the stretching ratio is usually about 3.0 to 7 times, preferably 3.5. ~ 6 times.
Then, heat treatment is subsequently performed usually at a temperature of about 150 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film.
In said extending | stretching, the method of performing extending | stretching of one direction in two or more steps is also employable. In that case, it is preferable to carry out so that the draw ratio of two directions finally becomes the said range, respectively.

Moreover, the simultaneous biaxial stretching method can also be employ | adopted regarding polyester film manufacture in this invention. The simultaneous biaxial stretching method simultaneously stretches the above-mentioned unstretched sheet in the machine direction (longitudinal direction) and the width direction (transverse direction) while the temperature is usually controlled at about 70 to 120 ° C., preferably 80 to 110 ° C. It is the method of making it orientate. The stretching ratio is usually about 4 to 50 times, preferably 7 to 35 times, more preferably 10 to 25 times in area ratio.
Then, heat treatment is subsequently performed usually at a temperature of about 170 to 250 ° C. under tension or relaxation within 30% to obtain a stretched and oriented film.
With respect to the simultaneous biaxial stretching apparatus adopting the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be adopted.

The thickness of the polyester film constituting the release film in the present invention is not particularly limited as long as the film can be formed as a film, but is usually 400 μm or less, preferably 5 to 250 μm, more preferably 12 to It is 200 μm.

<Haze>
The transparency of the polyester film in the present invention is not particularly limited, but when transparency is required, the haze of the entire release film is preferably 15% or less, more preferably 5% or less, and further preferably Is less than 3%. For example, when using a release film for protection of an optical member etc., the product inspection (foreign material test | inspection etc.) of the said optical member may be performed from on the release film in the state to which the release film was stuck. In such a case, if the haze of the release film is greater than 15%, a false recognition may occur as a foreign matter.
In the present invention, haze can be measured, for example, according to JIS K7136.
The above haze value is the same for the release film of the present invention, and the same is also true for the preferable numerical range.

<Total light transmittance>
The total light transmittance of the polyester film in the present invention is not particularly limited, but when transparency is required, it is preferably 80% or more, more preferably 85% or more.
In the present invention, the total light transmittance can be measured, for example, according to JIS K7361-1.
In addition, the value of said total light transmittance is the same also about the release film of this invention, and is the same also about a preferable numerical range.

<Intrinsic viscosity>
The intrinsic viscosity of the polyester is preferably 0.30 to 0.90 dL / g, more preferably 0.40 to 0.80 dL / g, and still more preferably 0.50 to 0.80 dL / g. By setting the intrinsic viscosity to 0.30 dL / g or more, a polyester film having sufficient heat resistance, mechanical strength and the like tends to be obtained. Further, by setting the intrinsic viscosity to 0.90 dL / g or less, the load may be suppressed in the extrusion step during the production of the polyester film, and sufficient productivity may be obtained.
In the present invention, the intrinsic viscosity of the polyester can be measured by the method described later in the examples, 1 g of polyester is precisely weighed, 100 mL of mixed solvent of phenol / tetrachloroethane = 50/50 (mass ratio) is added and dissolved. It can be measured at 30 ° C. using a fully automatic solution viscometer.

[Crosslinked resin layer]
The crosslinked resin layer which comprises the release film in this invention is demonstrated.
The crosslinked resin composition forming the crosslinked resin layer contains an ionic polymer (A) having a cationic group and a crosslinking agent (C). Moreover, it is preferable that the crosslinked resin composition which forms a crosslinked resin layer further contains a binder polymer (B) from an adhesive viewpoint with a release layer.

<Ionic Polymer (A) Having a Cationic Group>
It is important that the crosslinked resin layer contains an ionic polymer (A) having a cationic group. By containing the ionic polymer (A) having a cationic group, not only good antistatic properties can be obtained, but also compatibility with the polyester enables melt recycling, and good productivity can be obtained. be able to.

The polymer having a cationic group includes a polymer having a quaternary ammonium salt and the like, and the polymer having an anionic group includes a polymer having a sulfonic acid group, a sulfuric acid ester group, a carboxyl group, a phosphate and the like. Among them, from the viewpoint of compatibility with other components in the crosslinked resin composition, it is more preferable to use a quaternary ammonium base-containing polymer, that is, a cationic polymer containing a quaternary ammonium salt as the ionic polymer.

The cationic polymer containing a quaternary ammonium salt refers to a polymer having a component containing a quaternary ammonium base in the main chain or side chain in the molecule. Examples of such a component include a pyrrolidinium ring, a quaternary compound of alkylamine, a copolymer of these with acrylic acid and methacrylic acid, a quaternary compound of N-alkylaminoacrylamide, a quaternary compound of polyallylamine, Examples include vinylbenzyltrimethylammonium salt, 2-hydroxy 3-methacryloxypropyltrimethylammonium salt and the like. Furthermore, these may be combined or copolymerized with other resins. Further, the type of anion used as a counter ion of these quaternary ammonium salts is not particularly limited, but, for example, anions such as halide ion, alkyl sulfate ion, alkyl sulfonate ion, and nitrate ion are generally used.

In the present invention, among the above-mentioned cationic polymers containing quaternary ammonium salts, from the viewpoint of preventing the decomposition of the antistatic agent at high temperature during the film formation of the release film, the quaternary ammonium salt is used as the main chain in the molecule. The cationic polymer contained is more preferable. Among them, from the viewpoint of strengthening the coating film strength by reaction with a crosslinking agent and the like and improving the solvent resistance, a polymer in which a reactive functional group such as methylol or epoxy is introduced into a cationic polymer containing quaternary ammonium salt is More preferable.
Further, as an example of such a cationic polymer, a homopolymer or copolymer of diallyldimethyl ammonium chloride is preferable.
The cationic polymer may be used alone or in combination of two or more.

The number average molecular weight of the cationic polymer is preferably 1000 or more, more preferably 2000 or more, and still more preferably 5000 or more. When the molecular weight is 1000 or more, the cationic polymer is not removed from the crosslinked resin layer to cause a decrease in performance over time, and the crosslinked resin layer is not likely to be sticky. In addition, when the molecular weight is low, the heat stability may be poor. In addition, the number average molecular weight is preferably 500000 or less, more preferably 100000 or less, since the viscosity of the coating solution is not too high and there is no possibility of causing problems such as deterioration of the coating property.
In the present invention, the number average molecular weight can be measured, for example, in terms of polystyrene by gel permeation chromatography (GPC).

The content of the ionic polymer (A) having a cationic group in the crosslinked resin composition is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, in terms of solid mass ratio. Preferably, it is 10 to 60% by mass. If the proportion of the ionic polymer (A) having a cationic group is 5% by mass or more, the antistatic performance of the crosslinked resin layer will be sufficient, and if it is 90% by mass or less, the transparency and durability of the crosslinked resin layer The quality also becomes good.

<Binder polymer (B)>
The binder polymer (B) constituting the cross-linked resin layer in the present invention means gel permeation chromatography (GPC) according to the macromolecular compound safety evaluation flow scheme (November 1975, sponsored by the Chemical Substances Council) It is a polymer compound having a number average molecular weight (Mn) of 1000 or more as measured, and has a film forming property, and does not include the ionic polymer (A) having the cationic group.

The binder polymer (B) constituting the crosslinked resin layer in the present invention may be a thermosetting resin or a thermoplastic resin. 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 fluoride, poly Fluororesins such as tetrafluoroethylene, ethylene tetrafluoroethylene copolymer, polychlorotrifluoroethylene, etc .; polyvinyl resins such as polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate, polyvinyl chloride; epoxy resins; oxetane resins; xylene resins; Aramid resin, polyimide silicone, polyurethane, polyurea, melamine resin, phenol resin, polyether, acrylic resin and these Copolymers. One or more of these may be used in combination.

The binder polymer (B) may be dissolved in an organic solvent as a raw material of the coating solution, or a functional group such as a hydroxyl group, a sulfo group or a carboxyl group is added to form an aqueous solution or a surfactant in combination. It may be dispersed in water. Moreover, additives, such as a viscosity modifier, may be contained in the binder polymer (B) as needed.

Among the binder polymers (B), from the viewpoint of adhesion to the release layer, any one or more types selected from polyester resins, acrylic resins, polyurethane resins, and vinyl resins are preferable, and a coating liquid is prepared. From the viewpoint of compatibility with other coating agents (substance constituting the coating liquid), it is more preferable to use one or more selected from acrylic resins and vinyl resins.

(Polyester resin)
The polyester resin used in the present invention is defined as a linear polyester having a dicarboxylic acid component and a glycol component as constituent components. As the dicarboxylic acid component, terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, phenylindane dicarboxylic acid, A dimer acid etc. can be illustrated. These components may be used alone or in combination of two or more.
Furthermore, together with these components, a small proportion of unsaturated polybasic acids such as maleic acid, fumaric acid, itaconic acid, etc., and hydroxycarboxylic acids such as p-hydroxybenzoic acid, p- (β-hydroxyethoxy) benzoic acid etc. It can be used. The proportion of the unsaturated polybasic acid component and the hydroxycarboxylic acid component is usually 10 mol% or less, preferably 5 mol% or less.

Moreover, as a glycol component, ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, dimethylol propionic acid Examples thereof include glycerin, trimethylolpropane, poly (ethyleneoxy) glycol, poly (tetramethylene oxy) glycol, an alkylene oxide adduct of bisphenol A, and an alkylene oxide adduct of hydrogenated bisphenol A. These can be used alone or in combination of two or more.

Among these glycol components, ethylene glycol, ethylene oxide adduct or propylene oxide adduct of bisphenol A, and 1,4-butanediol are preferable, and ethylene glycol adduct or propylene oxide adduct of bisphenol A is more preferable.

Further, it is possible to copolymerize the polyester resin with a compound having a sulfonic acid group or a compound having a carboxylic acid group in order to facilitate aqueous liquefaction, which is preferable.
Examples of compounds having this sulfonate group include 5-sodium sulfoisophthalic acid, 5-ammonium sulfoisophthalic acid, 4-sodium sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid, 2-sodium sulfoisophthalic acid, 5-potassium Preferred examples include sulfonic acid alkali metal salts or sulfonic acid amine salts such as sulfoisophthalic acid, 4-potassium sulfoisophthalic acid, 2-potassium sulfoisophthalic acid, sodium sulfosuccinic acid and the like.

Examples of compounds having this carboxylic acid group include trimellitic acid anhydride, trimellitic acid, pyromellitic acid anhydride, pyromellitic acid, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylol propionic acid, etc., or mono alkali metal salts thereof Etc. The free carboxyl group is reacted with an alkali metal compound or an amine compound after copolymerization to form a carboxylate group. From these compounds, one or more may be appropriately selected, and polyesters obtained by synthesizing by a conventional polycondensation reaction may be used.

The glass transition temperature (hereinafter sometimes abbreviated as Tg) of the polyester resin is preferably 40 ° C. or more, more preferably 60 ° C. or more. When the Tg is 40 ° C. or higher, there is no possibility of causing a problem such as easy blocking when the coating thickness of the crosslinked resin layer is increased for the purpose of improving adhesion.
In the present invention, the glass transition temperature can be measured, for example, by a method in accordance with JIS K 7121: 1987.

(acrylic resin)
The acrylic resin used in the present invention is defined as a polymer containing acrylic and methacrylic monomers as a polymerizable monomer having a carbon-carbon double bond. These may be homopolymers or copolymers. Also included are copolymers of these polymers with other polymers such as polyesters, polyurethanes and the like. For example, a block copolymer and a graft copolymer. Further included are polyester solutions, or polymers obtained by polymerizing polymerizable monomers having carbon-carbon double bonds in polyester dispersion (in some cases, mixtures of polymers). Also included are polyurethane solutions, polymers obtained by polymerizing polymerizable monomers having carbon-carbon double bonds in polyurethane dispersion (in some cases, mixtures of polymers). Similarly, other polymer solutions, or polymers obtained by polymerizing polymerizable monomers having carbon-carbon double bonds in the dispersion (in some cases, polymer mixtures) are also included.

The polymerizable monomer having a carbon-carbon double bond other than acrylic and methacrylic monomers is not particularly limited, but typical compounds include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, and the like. Various carboxyl group-containing monomers such as fumaric acid, maleic acid, citraconic acid and salts thereof; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, mono Various hydroxyl group-containing monomers such as butyl hydroxyl fumarate, monobutyl hydroxy itaconate; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate Various kinds of ) Acrylate; (meth) acrylamide, diacetone acrylamide, N- methylol acrylamide or (meth) various nitrogen-containing vinyl monomers such as acrylonitrile. Among them, an acrylic resin obtained by polymerizing one or more selected from a carboxyl group-containing monomer, a (meth) acrylic acid ester, and a nitrogen-containing vinyl monomer.
In the above, for example, "(meth) acrylate" means acrylate and methacrylate.

In addition, in combination with these, polymerizable monomers as shown below can be copolymerized. That is, various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene and vinyltoluene, various vinyl esters such as vinyl acetate and vinyl propionate; γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, Various silicon-containing polymerizable monomers such as methacryloyl silicon macromer and the like; phosphorus-containing vinyl monomers; vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, trifluorochlorethylene, tetrafluoroethylene, chlorotrifluoroethylene And various halogenated vinyls such as hexafluoropropylene; various conjugated dienes such as butadiene.
These polymerizable monomers may be used alone or in combination of two or more.

In the acrylic resin, Tg is preferably 40 ° C. or more, more preferably 60 ° C. or more. When the Tg is 40 ° C. or higher, there is no possibility of causing a problem such as easy blocking when the coating thickness of the crosslinked resin layer is increased for the purpose of improving adhesion.

(Polyurethane resin)
The polyurethane resin in the present invention refers to a polymer compound having a urethane bond in the molecule. Among them, water-dispersible or water-soluble polyurethane resins are preferable in consideration of the suitability for in-line coating. In order to impart water dispersibility or water solubility, it is possible to introduce 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 into the polyurethane resin. Among the above-mentioned hydrophilic groups, a carboxylic acid group or a sulfonic acid group is preferably used from the viewpoint of improving the coating film physical properties and the adhesion.

As a specific production example of the polyurethane resin, for example, a method of using a reaction of a hydroxyl group-containing compound and an isocyanate compound can be mentioned. As a hydroxyl group containing compound used as a raw material, a polyol is used suitably, For example, polyether polyols, polyester polyols, polycarbonate-type polyols, polyolefin polyols, and acryl polyols are mentioned. These compounds may be used alone or in combination of two or more.

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

Polyester polyols include those obtained from the reaction of polyhydric carboxylic acids or their acid anhydrides with polyhydric alcohols.
Examples of polyvalent carboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid and the like. One or more of these may be used in combination.
As 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-nonane , 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexanediol, bishydroxymethyl Examples thereof include cyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamines, lactone diols and the like.

Polycarbonate-based polyols are polycarbonate diols obtained by polyhydric alcohol and dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate or the like by a dealcoholization reaction, for example, poly (1,6-hexylene) Carbonate, poly (3-methyl-1,5-pentylene) carbonate and the like can be mentioned.

As an isocyanate compound used to obtain a polyurethane resin, aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, α ′ Aliphatic diisocyanates having an aromatic ring such as tetramethyl xylylene diisocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, aliphatic diisocyanates such as hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, Dicyclohexyl Tan diisocyanate, and cycloaliphatic diisocyanates such as isopropylidene dicyclohexyl diisocyanate.

When synthesizing a polyurethane resin, a conventionally known chain extender may be used, and as a chain extender, it 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 two amino groups is generally used.

Examples of chain extenders having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol, and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, neopentyl glycol hydroxypivalate, etc. And glycols such as ester glycols of Moreover, as a chain extender having two amino groups, for example, aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3 -Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, and Aliphatic diamines such as 10-decanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropyritin cyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane And 1,3-bis (aminomethyl) Alicyclic diamines such as cyclohexane.

(Vinyl resin)
Examples of the vinyl resin include polystyrene, poly α-methylstyrene, sodium polystyrene sulfonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl ether, sodium polyvinyl sulfonate, sodium polymethacrylate, polyvinyl alcohol, polyvinyl butyral and the like. Be In addition, it is a polymer or copolymer obtained from a monomer having an unsaturated double bond in a molecule having as a main component thereof, a substantially composite structure such as vinyl resin-grafted polyester and vinyl resin-grafted polyurethane. The resin which it has can also be used. One or more of these may be used in combination.
Among the vinyl resins, polyvinyl alcohol is preferably used from the viewpoint of compatibility with other coating agents (substance constituting the coating solution) at the time of preparation of the coating solution.

Polyvinyl alcohol can be synthesized by a usual polymerization reaction, for example, by adding an alkali catalyst such as sodium hydroxide or potassium hydroxide to a solution containing polyvinyl acetate produced by polymerizing vinyl acetate, and then desired. It can be partially saponified to produce a degree of saponification. Also, polyvinyl alcohol is preferably water soluble.

The polymerization degree of polyvinyl alcohol is not particularly limited, but generally 100 or more, preferably 300 to 40,000. If the polymerization degree is 100 or more, there is no possibility that the water resistance of the crosslinked resin layer will be reduced. The degree of saponification of the polyvinyl alcohol used in the present invention is not particularly limited, but is usually 70 mol% or more, preferably 80 mol% or more, and preferably 99.9 mol% or less.
The degree of saponification can be measured according to the method described in JIS K6726 (1994).
The degree of polymerization (viscosity average degree of polymerization) can be measured in accordance with the method described in JIS K 6726 (1994).

The content of the binder polymer (B) in the crosslinked resin composition is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and still more preferably 10 to 60% by mass in terms of solid content mass ratio. %. When the content of the binder polymer (B) is in the above range, the strength of the obtained crosslinked resin layer and the adhesion to the release layer can be sufficiently obtained.

<Crosslinking agent (C)>
The crosslinking resin composition in the present invention contains a crosslinking agent (C). The crosslinking agent mainly improves the cohesion, surface hardness, scratch resistance, solvent resistance, water resistance, etc. of the crosslinked resin layer by crosslinking reaction with a functional group contained in another resin or compound, or self-crosslinking. be able to.

In the present invention, the crosslinking agent (C) which can be used is not particularly limited, and any kind of crosslinking agent can be used. For example, melamine compounds, guanamine compounds, alkylamide compounds, and polyamide compounds, glyoxals, carbodiimide compounds, epoxy compounds, oxazoline compounds, aziridine compounds, isocyanate compounds, silane coupling agents, dialcohol aluminate coupling agents, Aldehyde compounds, zircoaluminate coupling agents, peroxides, heat or photoreactive vinyl compounds, photosensitive resins and the like are suitably used. Among them, from the viewpoint of synergistically obtaining good adhesion to the release layer, it is preferable to use a crosslinking agent or a silane coupling agent of a melamine compound or an epoxy compound.
Moreover, these crosslinkers include polymer crosslinkable compounds having a reactive group in the other polymer skeleton, and further, in the present invention, one or more of these crosslinkers are used in combination. You may

(Melamine compound)
The melamine compound is a compound having a melamine skeleton in the compound. For example, an alkylolated melamine derivative, a compound obtained by reacting an alcohol with an alkylolated melamine derivative to partially or completely etherify, and a mixture thereof can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol etc. are used suitably. Moreover, as a melamine compound, any of a monomer or the multimer more than a dimer may be sufficient, or you may use these mixtures. Furthermore, a product obtained by co-condensing urea or the like with part of melamine can also be used, and a catalyst can also be used to increase the reactivity of the melamine compound. Among them, hexamethoxymethylolmelamine is preferably used as the melamine compound.

(Epoxy compound)
An epoxy compound is a compound which has an epoxy group in a molecule | numerator, and a compound obtained as a result of reaction of an epoxy group. Examples of compounds having an epoxy group in the molecule include condensates of epichlorohydrin with hydroxyl groups or amino groups such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A, etc. Polyepoxy compounds, diepoxy There are compounds, monoepoxy compounds, glycidyl amine compounds and the like. Examples of polyepoxy compounds include sorbitol, polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylol Examples of propane polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl Ether, polypropylene glycol diglycidyl ether, Examples of the lithium tetramethylene glycol diglycidyl ether and monoepoxy compound include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and as the glycidyl amine compound, N, N, N ', N',-tetraglycidyl-m. And xylylenediamine, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like. Among them, it is preferable to use polyglycerol polyglycidyl ether as the epoxy compound.

(Silane coupling agent)
The silane coupling agent is an alkoxysilane compound having a general formula of X-Si (OR) ₃ which contains two of reactive group site X and alkoxyl group site OR in the molecule, Any silane coupling agent that is synthetically possible can be used in the present invention as long as it is a silane compound containing a reactive group site X and an alkoxyl group site OR in the molecule.
R contained in the silane coupling agent is usually a methyl group or an ethyl group, but may be any alkyl group or a derivative thereof as long as synthetically possible, such as a butyl group or an isopropyl group.

As for the reactive group site X possessed by the silane coupling agent, reactive groups such as double bond group, amino group, epoxy group, mercapto group, sulfide group, isocyanate group, ureido group, chloropropyl group, hydroxyl group etc. It is possible to use any structure as the reactive group site X as long as the structure has a structure.

In the present invention, among the silane coupling agents, the use of a silane coupling agent having a structure containing an amino group is preferable from the viewpoint of the coating appearance and the effect of improving transparency, and a silane cup having a structure containing an epoxy group The use of a ring agent (eg, 3-glycidoxypropyltrimethoxysilane) or a silane coupling agent having a structure containing a vinyl group is more preferable.

The content of the crosslinking agent (C) in the crosslinked resin composition is preferably 1 to 90% by mass, more preferably 3 to 50% by mass, and still more preferably 5 to 40% by mass in terms of solid content mass ratio. %. When the ratio of the crosslinking agent (C) is in the above range, sufficient adhesion to the release layer by synergy with the binder polymer (B) can be obtained.

(particle)
In the present invention, particles may be contained in the crosslinked resin layer for the purpose of improving the adhesion and slipperiness of the crosslinked resin layer. The average particle diameter is not particularly limited, but is preferably 1.0 μm or less, more preferably 0.5 μm or less, and still more preferably 0.2 μm or less from the viewpoint of film transparency. Moreover, it is preferably 0.01 μm or more from the viewpoint of obtaining the adhesion and slipperiness of the crosslinked resin layer.
Specific examples of the particles include inactive inorganic particles such as silica, alumina, calcium carbonate and titanium dioxide, fine particles obtained from polystyrene resins, polyacrylic resins and polyvinyl resins, organic particles represented by cross-linked particles thereof, etc. Can be mentioned.
In the present invention, the average particle size of the particles can be measured, for example, by the method described later in the Examples.

(Others)
Further, the cross-linked resin layer may optionally contain a surfactant, an antifoamer, a coating property improver, a mold release agent, a thickener, an organic lubricant, an antistatic agent, as long as the gist of the present invention is not impaired. A conductive agent, a light absorber such as ultraviolet light, an antioxidant, a foaming agent, a dye, a pigment and the like may be contained.

The analysis of the components in the crosslinked resin layer can be performed, for example, by analysis of TOF-SIMS, photoelectron spectroscopy (XPS), fluorescent X-ray or the like.

<Formation of Crosslinked Resin Layer>
Next, the formation of a crosslinked resin layer provided on at least one surface of the polyester film constituting the release film of the present invention will be described.
The crosslinked resin layer may be provided by in-line coating which treats the film surface during the stretching process of the polyester film, or off-line coating may be applied outside the system on the film once produced. Since coating is possible simultaneously with film formation, in-line coating is preferably used from the point that manufacturing can correspond at low cost and that the thickness of the crosslinked resin layer can be changed by the draw ratio.

About in-line coating, although it is not limited to the following, for example, in successive biaxial stretching, a coating process can be applied before transverse stretching, especially after longitudinal stretching is completed. When a crosslinked resin layer is provided on a polyester film by in-line coating, coating becomes possible at the same time as film formation, and the crosslinked resin layer is cured by heat curing of the crosslinked resin composition by being treated at high temperature during transverse stretching. It can be formed to produce a film suitable as a polyester film.
The curing conditions for forming the cross-linked resin layer are not particularly limited, but it is generally preferable to conduct at 170 ° C. or more for 2 seconds or more as a standard.

When providing a crosslinked resin layer by in-line coating, it is preferable to carry out in the way of apply | coating a coating liquid on a polyester film as aqueous solution or aqueous dispersion of the crosslinked resin composition containing the above-mentioned series of compounds. As a method of applying a coating solution containing a crosslinked resin composition, conventionally known coating methods such as reverse roll coating, gravure coating, bar coating, and doctor blade coating can be used.
In addition, a small amount of organic solvent may be contained in the coating solution for the purpose of improving the dispersibility in water, improving the film forming property, and the like, as long as the gist of the present invention is not impaired. The organic solvent can be used alone or in combination of two or more. The content of the organic solvent in the coating solution is preferably 10% by mass or less, more preferably 5% by mass or less.

Moreover, when providing a crosslinked resin layer by off-line coating, you may use the coating liquid using the organic solvent.
Specific examples of the organic solvent include aliphatic or alicyclic alcohols such as n-butyl alcohol, n-propyl alcohol, isopropyl alcohol, ethyl alcohol and methyl alcohol, and glycols such as propylene glycol, ethylene glycol and diethylene glycol Glycol derivatives such as n-butyl cellosolve, ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether, ethers such as dioxane and tetrahydrofuran, esters such as ethyl acetate and amyl acetate, ketones such as methyl ethyl ketone and acetone, N-methyl pyrrolidone And the like.

Further, regardless of the off-line coating or the in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination, as necessary.

As a method of forming a crosslinked resin layer, for example, gravure coat, reverse roll coat, die coat, air doctor coat, blade coat, rod coat, bar coat, curtain coat, knife coat, transfer roll coat, squeeze coat, curtain coat, Conventionally known coating methods such as impregnation coating, kiss coating, spray coating, calender coating, and extrusion coating can be used.

<Film thickness of crosslinked resin layer>
The film thickness of the crosslinked resin layer provided on the polyester film in the present invention is preferably 0.01 to 3 μm, more preferably 0.01 to 3 μm from the viewpoint of exhibiting various functionalities when viewed as a final film. It is preferably 1 μm, more preferably 0.01 to 0.3 μm.
The film thickness of the crosslinked resin layer in the present invention is obtained, for example, by staining the release film with a heavy metal such as a ruthenium compound or an osmium compound and adjusting the cross section of the release film by the ultrathin section method. The cross-linked resin layer of the cross section of the release film can be measured at a plurality of places at random and the average value can be calculated and determined.
The coating amount of the coating solution containing the crosslinked resin composition is usually 0.01 to 3 g / m ² , preferably 0.01 to 1 g / m ² , and more preferably 0.01 to 0.3 g / m ² . is there. When the amount is 0.01 g / m ² or more, sufficient performance in adhesion to the release layer (adhesion resistance) and antistatic performance can be obtained. When the amount is 3 g / m ² or less, the crosslinked resin layer has an appearance and transparency There is no possibility that the blocking of the film and the reduction of the productivity due to the reduction of the line speed occur. In the present invention, the coating amount can be calculated from the mass of liquid per application time (before drying), the concentration of the non-volatile portion of the coating liquid, the coating width, the stretching ratio, the line speed and the like.

[surface treatment]
The polyester film used in the present invention can be subjected to various surface treatments separately from the crosslinked resin layer. Specifically, it can be applied to the polyester film on the back surface side of the crosslinked resin layer, or the like before the crosslinked resin layer is formed on the polyester film. Conventionally known techniques can be used for various surface treatments and various functional layers. For example, surface treatment may be surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet light treatment, high frequency treatment, microwave treatment, glow discharge treatment, active plasma treatment, laser treatment and the like.

In the polyester film used in the present invention, a crosslinked resin layer having the same constitution as the crosslinked resin layer may be provided on the back surface side of the crosslinked resin layer, or various functional layers may be separately provided. As various functional layers, an adhesive layer, an antistatic layer, a bleed-out component sealing layer, a refractive index adjustment layer, a light absorption layer, a light transmittance improving layer, an antifogging layer, a barrier coat layer, a hard coat layer, adhesion Layers, layers in which these functionalities are combined, and the like can be mentioned. The functional layer may be a single layer, or may be configured of two or more layers.

[Release layer]
Next, the release layer in the present invention will be described. The release layer which comprises the release film of this invention is formed using a release agent composition.

<Polydimethyl siloxane>
The release agent composition according to the present invention has a first polydimethylsiloxane having at least one alkenyl group in one molecule and an at least one hydrosilyl group in one molecule as an addition reaction type silicone resin. And 2 polydimethylsiloxanes. By having the first polydimethylsiloxane and the second polydimethylsiloxane contained in the release agent composition, the adhesion between the release resin and the crosslinked resin layer constituting the release film over time is sufficiently obtained. Can.

The alkenyl group contained in the first polydimethylsiloxane used in the present invention is a monovalent hydrocarbon group such as vinyl group, allyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, etc. It can be mentioned. Among them, vinyl and hexenyl are preferable from the viewpoint of the reactivity with the hydrosilyl group.

The alkenyl group is preferably contained in 3 to 90 mmol, more preferably 6 to 45 mmol, in 30 g of the first polydimethylsiloxane. Further, in 30 g of the second polydimethylsiloxane, the hydrosilyl group is preferably contained in 6 to 450 mmol, more preferably in 15 to 450 mmol.
Furthermore, 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 500 or more and 50000 or less, preferably 800 or more or 30000 or less, and more preferably 2000 or more or 20000 or less. If the weight average molecular weight of the first polydimethylsiloxane is less than 500, the reactivity is high, and the reaction proceeds in the coating solution, so the desired light peel strength can not be expressed, and if it exceeds 50,000, the reactivity is not good. It becomes worse and does not develop the desired light peeling force.

The weight average molecular weight of the second polydimethylsiloxane is 120 or more and 20000 or less, preferably 150 or more or 10000 or less, and more preferably 200 or more or 5000 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 coating liquid, so the desired light peel strength can not be expressed, and if it exceeds 20000, the reactivity is not good. It becomes worse and does not develop the desired light peeling force.
In addition, the weight average molecular weight in this invention is a value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

Between the polydimethylsiloxane having an alkenyl group and the polydimethylsiloxane having a hydrosilyl group, a crosslinked structure is formed by the reaction of the alkenyl group and the hydrosilyl group. Here, in the present invention, setting the weight average molecular weights of the first polydimethylsiloxane and the second polydimethylsiloxane to the above upper limit or less, respectively, forms a releasing layer using a component having a molecular weight lower than that of the prior art as a raw material. It means to do. Therefore, the release layer in the present invention has a high crosslinking density, in other words, it is possible to lower the molecular weight between crosslinking points. In the present invention, if the release layer has such a structure, it is possible not only to reduce the peeling force with respect to the adherend (light peelability) but also to stabilize the effect over time. I found it.
When the weight average molecular weight of the polydimethylsiloxane having an alkenyl group or the polydimethylsiloxane having a hydrosilyl group is higher than the upper limit defined in the present invention, it is good immediately after the release film and the adherend are adhered. Even if light peelability is exhibited, the peel strength increases with time. This is because, when the molecular weight between the crosslinking points of the release layer is large, the molecular chain of dimethylsiloxane forming the release layer and the substance forming the adherend (usually the polymer chain forming the adhesive layer) are mutually different. It is believed that the molecular motion causes micro entanglement over time.
According to the study of the present inventor, although the light releasability is exhibited when the crosslinking density of the release layer is increased, the adhesion inside the release film, that is, the adhesion between the release layer and the crosslinked resin layer It has been confirmed that there is a possibility that delamination may occur. It is presumed that this is because the above-mentioned properties of the release layer may contribute not only to the adherend but also to the crosslinked resin layer.
Then, the present inventor found that it is preferable to contain an organic silicon compound in the mold release layer, as described later. That is, as a release agent composition, an organosilicon compound is contained together with the first and second polydimethylsiloxanes, and when these are cured to form a release layer, it has light releasability to an adherend, It was confirmed that the interlayer adhesion in the release film is good. In the present invention, it has also been found that, by using an organosilicon compound in combination with the release agent composition as described above, it is possible to exhibit an anchor effect on the crosslinked resin layer.
Whether or not the weight average molecular weight of the first and second polydimethylsiloxanes falls within the specified range can be confirmed by molecular weight measurement at the raw material stage, but in the case of a release film, for example, the following method It can be estimated by However, the confirmation method is not limited to the following.
(1) Extract the release layer with an organic solvent or the like, and measure the molecular weight of the unreacted component,
(2) Analysis of the crosslinking point by tetraethoxysilane analysis to estimate the molecular weight,
(3) The electronic state of the release layer is analyzed by X-ray photoelectron spectroscopy (XPS), and the crosslink density is measured to estimate the molecular weight between crosslink points.
The content of each of the first polydimethylsiloxane and the second polydimethylsiloxane in the release agent composition (the first polydimethylsiloxane / the second polydimethylsiloxane) is from the viewpoint of the formation of the release layer. And preferably 20/80 to 90/10 (% by mass), and more preferably 50/50 to 80/20 (% by mass).

Platinum-based catalyst
The release agent composition preferably contains a platinum-based catalyst that promotes addition type reaction in order to make the release layer smooth and robust. As platinum-based catalysts, platinum-based compounds such as chloroplatinic acid, alcohol solutions of chloroplatinic acid, complexes of chloroplatinic acid and olefin, complexes of chloroplatinic acid and alkenyl siloxane, platinum black, platinum-supported silica, supported platinum An activated carbon is illustrated. The platinum-based catalyst may be used alone or in combination of two or more.

The content of the platinum-based catalyst in the release agent composition is preferably 0.3 to 3.0% by mass, more preferably 0.5 to 2.0% by mass. If the content of the platinum-based catalyst in the release layer is 0.3% by mass or more, problems such as surface deterioration may occur due to defects in peeling force and insufficient curing reaction in the crosslinked resin layer. There is no fear, and if the content of the platinum-based catalyst in the release layer is 3.0% by mass or less, the reactivity is enhanced, and there is no risk of causing process defects such as generation of gel foreign matter.

By forming a release layer using the release agent composition which satisfy | fills said conditions, in use of a substrate-less double-sided adhesive sheet, a release film can be peeled extremely smoothly.

<Reactive group-containing organosilicon compounds>
In addition, in the release agent composition for forming the release layer in the present invention, in order to improve the adhesion of the coating film between the release layer and the polyester film, it is possible to use ones other than the first and second polydimethylsiloxanes. It is preferable to contain a reactive group-containing organic silicon compound (hereinafter sometimes simply referred to as an organic silicon compound).

The reactive group-containing organic silicon compound is an organic silicon compound having a reactive group such as an epoxy group, a mercapto group, a (meth) acryloyl group, a haloalkyl group, and an amino group in the molecular structure in the present invention. Both high molecular weight compounds and low molecular weight compounds can be used. The reactive group-containing organic silicon compound does not include the first and second polydimethylsiloxanes.

Among the above organic silicon compounds, it is preferable to use an organic silicon compound represented by the following general formula (I).
Si (X ¹ ) _d (Y) _e (R ¹ ) _f (I)
[In the above-mentioned formula, X ¹ is an organic group having at least one selected from an epoxy group, a mercapto group, a (meth) acryloyl group, an alkenyl group, a haloalkyl group and an amino group, R ¹ is a monovalent hydrocarbon group, And Y is a hydrolyzable group, d is an integer of 1 or 2, e is an integer of 2 or 3, f is an integer of 0 or 1, and d + e + f = 4 is there]

The organic silicon compound represented by the above general formula (I) has two (D unit source) or three (D unit source) having a hydrolyzable group Y capable of forming a siloxane bond by hydrolysis / condensation reaction Source) can be used.

In the general formula (I), the monovalent hydrocarbon group R ¹ is one having 1 to 10 carbon atoms, and in particular, a methyl group, an ethyl group or a propyl group is preferable.

In the general formula (I), examples of the hydrolyzable group Y include the following. That is, they are methoxy group, ethoxy group, butoxy group, isopropenoxy group, acetoxy group, butanoxym group, amino group and the like. These hydrolyzable groups may be used alone or in combination of two or more. The application of a methoxy group or an ethoxy group is particularly preferable because it can impart good storage stability to the coating material and has adequate hydrolyzability.

In the present invention, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (specific examples of the organic silicon compound contained in the release agent composition in the present invention 3,4-Epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 5-hexenyl Examples thereof include trimethoxysilane, p-styryltrimethoxysilane, trifluoropropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and γ-glycidoxypropylmethyldiisopropenoxysilane.

The content of the organic silicon compound in the release agent composition is preferably 0.1 to 5.0% by mass, more preferably 0.3 to 2.0% by mass, and still more preferably 0.3 to 1 .5 mass%. If the content of the organosilicon compound is 0.1% by mass or more, desired adhesion can be secured, and if it is 5.0% by mass or less, the adhesiveness to the cross-linked resin layer of the other member to be bonded There is no risk of problems such as being unable to be easily peeled off in situations where it is necessary to originally peel off.

<Non-reactive silicone resin>
The release agent composition may further contain a non-reactive silicone resin in order to impart light releasability to the release film.
The weight average molecular weight of the non-reactive silicone resin is preferably 50000 or more and 500000 or less.

As said non-reactive silicone resin, organopolysiloxane shown by following General formula (II) is preferable.
R ² ₃ SiO (R ² ₂ SiO) _m SiR ² ₃ ... (II)
(Wherein R ² is the same or different monovalent hydrocarbon group having no aliphatic unsaturated bond, and m is a positive integer)

The content of the nonreactive silicone resin in the release agent composition is preferably 1 to 10% by mass, and more preferably 1 to 5% by mass. If the content of the non-reactive silicone resin is 1% by mass or more, a sufficient light peeling effect is exhibited, and if 10% by mass or less, sufficient curability and adhesiveness can be obtained.

<Peeling control agent>
The release agent composition may contain various release control agents in order to adjust the release property and the like of the release layer. When the peeling force is to be made to be heavy peeling, adjustment is usually carried out by incorporating an appropriate amount of a silica particle, a silicone type having a heavy peeling force, or the like into the releasing agent composition in order to obtain a desired peeling force.
Shin-Etsu Chemical Co., Ltd. KS-3800, X-92-183, Toray Dow Corning Co., Ltd. SDY7292, BY24-843, BY24-4980 are examples of the heavy peeling agent marketed. Be done.

In the case of lightening the peeling force, various low molecular weight siloxanes (non-reactive low molecular weight silicone compounds) are selected, the content is adjusted appropriately for the releasing layer, and the siloxane transfer component exerts releasing performance. Like. Examples of low molecular weight siloxane compounds include hexamethyl cyclotrisiloxane, octamethyl cyclotetrasiloxane, decamethyl cyclopentasiloxane and the like. In addition, as other compounds of low molecular weight cyclic siloxanes, there are a molecular chain both terminal trimethylsiloxy group-capped dimethylsiloxane oligomer; a molecular chain both terminal dimethylhydroxysiloxy group-capped dimethylsiloxane oligomer etc., and the above-mentioned compounds are mixed if necessary. You may use it.

The content of these low molecular weight siloxane compounds in the releasing agent composition is preferably 0.1 to 15.0% by mass, more preferably 0.1 to 10.0% by mass, still more preferably 0.1. It is ̃5.0 mass%. When the content of the low molecular weight siloxane is 0.1% by mass or more, the releasable component is not too small and the releasability can be exhibited, and when it is 15.0% by mass or less, the mobilizable component is There is no possibility of causing process contamination without excessive precipitation.

<Reaction inhibitor>
In addition, since the addition type reaction between the first polydimethylsiloxane and the second polydimethylsiloxane is very reactive, the releasing agent composition optionally contains acetylene alcohol as a reaction inhibitor, as needed. May be The acetylene alcohol is an organic compound having a carbon-carbon triple bond and a hydroxyl group, preferably 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and phenyl. It is a compound selected from the group consisting of butynol. The reaction inhibitor may be used alone or in combination of two or more.

<Others>
Furthermore, to the extent that the gist of the present invention is not impaired, the release agent composition for forming the release layer may, if necessary, be an antifoamer, a coatability improver, a thickener, inorganic organic particles, organic lubrication An agent, an antistatic agent, a conductive agent, an ultraviolet absorber, an antioxidant, a foaming agent, a dye, a pigment and the like may be contained.

<Formation of Release Layer>
Then, formation of the mold release layer which comprises the mold release film of this invention is demonstrated.
The release film of the present invention is produced by providing a crosslinked resin layer on at least one surface of a polyester film stretched at least in a uniaxial direction, and further laminating a release layer on the crosslinked resin layer.
The release layer may be in-line coating or off-line coating as in the case of the cross-linked resin layer, but off-line coating is preferably used in that the release layer composition can be uniformly applied at high speed.
As a method of providing a release layer composition, conventionally known coating methods such as reverse roll coating, gravure coating, bar coating, and doctor blade coating can be used as in the case of the crosslinked resin layer.

When the release layer is provided by off-line coating, it is preferable to apply the coating solution on the crosslinked resin layer as a solution or dispersion of a release agent composition containing the above-mentioned series of compounds. The solvent may be water or an organic solvent in producing a coating solution containing the release agent composition, but an organic solvent is preferable from the viewpoint of compatibility with the release agent composition.
Specific examples of the organic solvent include aliphatic or alicyclic alcohols such as n-butyl alcohol, n-propyl alcohol, isopropyl alcohol, ethyl alcohol and methyl alcohol, and glycols such as propylene glycol, ethylene glycol and diethylene glycol Glycol derivatives such as n-butyl cellosolve, ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether, ethers such as dioxane and tetrahydrofuran, esters such as ethyl acetate and amyl acetate, ketones such as methyl ethyl ketone and acetone, N-methyl pyrrolidone And the like.

The curing conditions for forming the release layer on the cross-linked resin layer of the polyester film are not particularly limited, and when the release layer is provided by off-line coating, usually 80 ° C. or more for 10 seconds or more, The heat treatment is preferably carried out with a temperature of 100 to 200 ° C. for 3 to 40 seconds, more preferably 120 to 180 ° C. for 3 to 40 seconds. Moreover, you may use together heat processing and active energy ray irradiations, such as ultraviolet irradiation, as needed. In addition, as an energy source for hardening by active energy ray irradiation, a well-known apparatus and energy source can be used.

In the present invention, the film thickness of the release layer provided on the crosslinked resin layer improves the adhesion with the crosslinked resin layer when viewed as a final film, and the light releasability from the substrateless double-sided pressure-sensitive adhesive sheet From the viewpoint of improvement, the thickness is usually 0.005 to 1 μm, preferably 0.01 to 1 μm, and more preferably 0.15 to 0.70 μm.
The amount of the release layer applied (after drying) is usually from 0.005 to 5 g / m ² , preferably from 0.01 to 1 g / m ² , more preferably from 0.15 to 0, from the viewpoint of coatability. It is in the range of .70 g / m ² . When the coating amount (after drying) is 0.005 g / m ² or more, it becomes possible to obtain a uniform coating film without lack of stability in terms of coating property. Moreover, if it is 5 g / m < ² > or less, there is no possibility that the coating-film adhesiveness of a release layer itself, hardening property, etc. may fall. The application amount can be calculated from the liquid mass per application time (before drying), the concentration of non-volatile matter in the application liquid, the application width, the draw ratio, the line speed, and the like.

<Performance of release film>
The release film of the present invention has good releasability and antistatic properties between the release film and the pressure-sensitive adhesive, has adhesion to the release layer even with time lapse, is melt recyclable, and has good productivity. , Its industrial value is high.

[Peeling force]
The release force of the release film of the present invention is 4 g / g at 180 ° release under the conditions of a release speed of 300 mm / min between the release film (surface on the release layer side) and the adhesive tape. It is 25 mm or less. When the peeling force exceeds 4 g / 25 mm, the peeling force is too heavy, so the convenience at the time of peeling the release film is lowered. The peeling force is more preferably 3 g / 25 mm or less from the viewpoint of the convenience of the release film. The lower limit of the peeling force is not particularly limited, but from the viewpoint of transportability, it preferably has adhesiveness between the release film and the pressure-sensitive adhesive film which is the adherend, and is 0.5 g / 25 mm or more More preferable.
The release force of the release film of the present invention is 4 g / 25 mm or less at 180 ° peeling, so that the release agent composition constituting the release layer of the release film has a weight average molecular weight of 500 to 50,000. A first polydimethylsiloxane having at least one alkenyl group in one molecule, and a second polydimethylsiloxane having a weight average molecular weight of 120 or more and 20,000 or less and at least one hydrosilyl group in one molecule; Is suggested to contain.

The peeling force of the release film of the present invention is measured in detail by the method described later in the examples.
In addition, although the release film of the present invention has good releasability, that is, light releasability, in the present invention, light releasability means that the force at the time of adhering and peeling a tape about 25 mm wide is 4 g / 25 mm or less In what is peelable.

The pressure-sensitive adhesive having good releasability and release film is not particularly limited, but an acrylic pressure-sensitive adhesive is preferable. The acrylic pressure-sensitive adhesive includes, as a main component, an acrylic copolymer obtained by copolymerizing a functional group-containing monomer with another monomer such as acrylic acid ester and methacrylic acid ester.

[Surface resistivity]
The surface specific resistance on the surface of the release layer of the release film of the present invention is preferably 1 × 10 ¹¹ Ω from the viewpoint of preventing peeling charge generated when releasing the release film and preventing adhesion of dust etc. to the adhesive surface. Or less, more preferably 1 × 10 ¹⁰ Ω or less. On the other hand, the lower limit of the surface specific resistance is not particularly limited, but 1 × 10 ¹ Ω or more is preferable.
The surface resistivity of the release film of the present invention can be measured in detail by the method described later in the examples.

[Adhesive film adhesion over time and productivity]
For example, even if a load is applied to the release layer after leaving the release film of the present invention in an atmosphere of 23 ° C. and 50% RH for 30 days, the release layer hardly comes off and maintains practicable adhesion. be able to.
In addition, even if the polyester film provided with the crosslinked resin layer is melt recycled, the compatibility between the crosslinked resin composition and the polyester is good, so that non-practical foreign matter is not generated and can be recycled. The productivity of the release film is good.

<Laminate>
The laminate of the present invention comprises a release film having a crosslinked resin layer on at least one side of a polyester film stretched in at least one uniaxial direction, and further having a release layer laminated on the crosslinked resin layer, and a double-sided pressure-sensitive adhesive sheet And a laminated body. In the laminate of the present invention, the crosslinked resin layer of the release film contains an ionic polymer (A) having a cationic group, and the release layer contains polydimethylsiloxane and has a film thickness of 0.01 to 1 μm. It is. By the film thickness of the said mold release layer being in the said range, it can fully have adhesiveness of the mold release layer which comprises a mold release film, and a crosslinked resin layer. On the other hand, when the film thickness of the release layer exceeds 1 μm, the adhesion between the release layer constituting the release film and the cross-linked resin layer becomes insufficient, and the surface of the release layer is easily peeled off. It is easy to occur. The thickness of the release layer is more preferably 0.15 to 0.70 μm.

Furthermore, the laminate of the present invention can have light releasability between the release film and the double-sided pressure-sensitive adhesive sheet. The peel force between the release layer surface of the release film and the double-sided pressure-sensitive adhesive sheet is 4 g / 25 mm or less at 180 ° peeling under the condition of 300 mm / min tensile speed. The peeling force is more preferably 3 g / 25 mm or less from the viewpoint of convenience of the release film. The lower limit of the peeling force is not particularly limited, but from the viewpoint of transportability, it preferably has adhesiveness between the release film and the pressure-sensitive adhesive film which is the adherend, and is 0.5 g / 25 mm or more More preferable.

Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited thereto.

The measurement method and evaluation method used in the present invention are as follows.
(1) Measuring Method of Intrinsic Viscosity of Polyester 1 g of polyester is precisely weighed, 100 mL of mixed solvent of phenol / tetrachloroethane = 50/50 (mass ratio) is added and dissolved, and a fully automatic solution viscometer (manufactured by Sentech Co., Ltd. It measured at 30 degreeC using DT553 ").

(2) Measurement of average particle diameter (d50: μm) of particles Integration in equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution measuring apparatus (manufactured by Shimadzu Corporation, "SA-CP type 3") The value of 50% of mass basis was made into the average particle diameter.

(3) Evaluation of releasability of release film On the surface of the release layer of the release film obtained in Examples and Comparative Examples, an adhesive tape (manufactured by Nitto Denko Corp., "No. 502", acrylic adhesive) After sticking one side of the above, it cut into size of 25 mm x 300 mm, and measured exfoliation power after leaving to stand at room temperature for 1 hour. Peeling force was evaluated by 180 ° peeling under a tensile speed of 300 mm / min using a tensile tester (“Intesco model 2001 type” manufactured by Intesco Corporation).
(Judgment criteria)
A (good): Peeling force value is 4 g / 25 mm or less.
C (poor): Peeling force value exceeds 4 g / 25 mm.

(4) Surface specific resistance of release film The release films obtained in Examples and Comparative Examples were measured using a high resistance measuring device HP4339B manufactured by Nippon Hewlett-Packard Co. and measuring electrode: HP16008B at 23 ° C., 50%. After adjusting the humidity for 30 minutes in a measurement atmosphere of RH, the surface specific resistance value was measured. The lower the surface specific resistance value, the better the action of preventing charging.
(Evaluation criteria)
A: R (Ω) is 1 × 10 ¹⁰ or less.
B: R (Ω) exceeds 1 × 10 ¹⁰ and 1 × 10 ¹¹ or less.
C: R (Ω) exceeds 1 × 10 ¹¹

(5) Evaluation of film adhesion over time of release film (practice characteristic substitution evaluation)
The release films obtained in Examples and Comparative Examples were left in an atmosphere of constant temperature and humidity, at 23 ° C. and 50% RH for 30 days, and the films were taken out. Thereafter, the release surface of the film was rubbed five times with a tentacle, and the degree of removal of the release layer was evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: There is no falling off of the release layer.
B: The release layer turned white but did not drop off.
C: Dropping of the release layer was confirmed.

(6) Productivity of mold release film (recyclability)
The polyester film provided with the crosslinked resin layer in Examples and Comparative Examples was mechanically cut and crushed to be regenerated flakes, and the regenerated flakes were directly added to the intermediate layer of the extruder without being heat-dried. Thereafter, the process was carried out in exactly the same manner as in the film formation of Example 1 to prepare a 38 μm-thick biaxially oriented polyester film, and the presence or absence of foreign matter in the polyester film was observed with an optical microscope.
If foreign matter is observed, it can not be melt-recycled, which suggests that the manufacturing cost of the release film is high and the productivity is low.
(Evaluation criteria)
A: Foreign matter is not observed.
C: Foreign matter is observed.

<Production of polyester>
Production Example 1 (Polyester (I))
Using 100 parts by mass of dimethyl terephthalate and 60 parts by mass of ethylene glycol as starting materials, 0.09 parts by mass of magnesium acetate tetrahydrate as an ester exchange catalyst is placed in a reactor, the reaction start temperature is 150 ° C., methanol is distilled off The reaction temperature was gradually raised with this and brought to 230 ° C. after 3 hours. After 4 hours, the transesterification was substantially terminated. After 0.04 parts by mass of ethyl acid phosphate was added to the reaction mixture, 0.04 parts by mass of antimony trioxide was added as a polymerization catalyst, and a polycondensation reaction was performed for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally it was 0.3 mmHg. After the start of the reaction, the reaction was stopped when the intrinsic viscosity corresponded to 0.63 dL / g due to the change of the stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the obtained polyester (I) was 0.63 dL / g.

Production Example 2 (Polyester (II))
In the production method of polyester (I), after adding 0.04 parts by mass of ethyl acid phosphate, 0.3 parts by mass of silica particles having an average particle diameter of 1.6 μm dispersed in ethylene glycol, 0.04 of antimony trioxide A polyester (II) was obtained using the same method as the polyester (I) production method, except that the polycondensation reaction was stopped when a mass part was added and the polycondensation reaction was stopped when the intrinsic viscosity corresponded to 0.65 dL / g. The intrinsic viscosity of the obtained polyester (II) was 0.65 dL / g.

<Crosslinked resin layer>
The following raw materials were used for the crosslinked resin composition which forms a crosslinked resin layer.
(A) Ionic Polymer A1: Poly (diallyldimethylammonium chloride) (number average molecular weight: about 30,000)
A2: A polymer compound (number average molecular weight: 21000) obtained by copolymerizing the constitutional unit of the following formula 1, the constitutional unit of the following formula 2, and the constitutional unit of the following formula 3 in a mass ratio of 80/10/10.
A3: A polymer having a cation in the side chain consisting of the structural units of the following formula 4 (number average molecular weight: 40000)

(B) Binder polymer B1: polyvinyl alcohol B2 having a degree of saponification of 88% and a degree of polymerization of 500: acrylic resin (water dispersion of acrylic resin polymerized according to the following composition)
Emulsion polymer of ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (% by mass) (emulsifier: anionic surfactant)
B3: Polyurethane resin A polyester polyol comprising 664 parts by mass of terephthalic acid, 631 parts by mass of isophthalic acid, 472 parts by mass of 1,4-butanediol, and 447 parts by mass of neopentyl glycol was obtained. Subsequently, 321 parts by mass of adipic acid and 268 parts by mass of dimethylol propionic acid were added to the obtained polyester polyol to obtain a pendant carboxyl group-containing polyester polyol A. Furthermore, 160 parts by mass of hexamethylene diisocyanate was added to 1880 parts by mass of the polyester polyol A to obtain a polyurethane resin.

(C) Crosslinking agent C1: hexamethoxymethylolmelamine C2: polyglycerol polyglycidyl ether C3: 3-glycidoxypropyltrimethoxysilane

(Others)
D1: Mixture of polyethylene dioxythiophene and polystyrene sulfonic acid (Stark Co., Ltd., Baytron PAG)
E1: Glycerin F1: Alumina surface-modified silica sol aqueous dispersion F2 having an average particle size of 0.02 μm: Silica particles having an average particle size of 0.07 μm

<Release layer>
The following raw materials were used for the mold release agent composition which forms a mold release layer.
The weight average molecular weight of the raw material was measured by gel permeation chromatography (GPC) in terms of polystyrene.
(Vinyl group-containing polydimethylsiloxane (vinyl group-containing PDMS))
a1: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 2000, 30 mmol of vinyl group in 30 g of PDMS)
a2: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 20000, 3 mmol of vinyl group in 30 g of PDMS)
a3: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 1000, 60 mmol of vinyl group in 30 g of PDMS)
a4: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 60000, 1 mmol of vinyl group in 30 g of PDMS)
a5: Vinyl-modified silicone resin having at least two vinyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 300, vinyl group 200 mmol in 30 g of PDMS)

(Hydrosilyl group-containing polydimethylsiloxane (hydrosilyl group-containing PDMS))
b1: Polymethyl hydrogen siloxane having at least two hydrosilyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 200, 300 mmol of hydrosilyl group in 30 g of PDMS)
b2: Polymethyl hydrogen siloxane having at least one hydrosilyl group in the structure of polydimethylsiloxane (weight average molecular weight: 5000, hydrosilyl group 6 mmol in 30 g of PDMS)
b3: Polymethyl hydrogen siloxane having at least one hydrosilyl group in the structure of polydimethylsiloxane (weight average molecular weight: 30,000, 1 mmol of hydrosilyl group in 30 g of PDMS)
b4: polymethyl hydrogen siloxane having at least two hydrosilyl groups in the structure of polydimethylsiloxane (weight average molecular weight: 100, 600 mmol of hydrosilyl group in 30 g of PDMS)

(Others)
c1: Platinum-based catalyst (Toray · Dow Corning “SRX-212”)
d1: Reactive group-containing organosilicon compound (epoxy siloxane, manufactured by Momentive, “Anchorsil 3000”)
d2: Reactive group-containing organosilicon compound (β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane)
d3: Reactive group-containing organosilicon compound (γ-glycidoxypropyltrimethoxysilane)

<Production of release film>
Example 1
(1) Laminated polyester film A mixed raw material in which polyesters (I) and (II) are mixed at a ratio of 90% and 10%, respectively, is used as the raw material for the outermost layer (surface layer), and polyester (I) is used as the raw material for the intermediate layer. Each is supplied to a platform extruder and melted at 285 ° C., and then co-extruded in a layer configuration of two types and three layers (surface layer / interlayer / surface layer) on a cooling roll set at 40 ° C., and solidified by cooling The unstretched sheet was obtained. Then, after stretching by 3.4 times in the longitudinal direction at a film temperature of 85 ° C. using the roll peripheral speed difference, the coating amount (water dispersion, solid content concentration 5 mass%) of the coating agent composition in Table 1 is applied The film is coated on one side of the film so that it has a predetermined amount (after drying), and then guided to a tenter, stretched 4.3 times in the lateral direction at 120 ° C., heat-treated at 225 ° C., and then the thickness of the polyester film There were obtained a laminated polyester film having a thickness of 38 μm (surface layer 5 μm / intermediate layer 28 μm / surface layer 5 μm) and the crosslinked resin layer 1 provided.
(2) Releasing Agent Composition According to the composition shown in Table 2, vinyl-modified silicone resin a1 having at least two vinyl groups in the structure of polydimethylsiloxane as the first polydimethylsiloxane (weight average molecular weight: 2000) And polymethyl hydrogen siloxane b1 (weight average molecular weight: 200) having at least two hydrosilyl groups in the structure of polydimethylsiloxane as a second polydimethylsiloxane, as a first polydimethylsiloxane / second polydimethyl Mix so that siloxane = 77/22 (parts by mass), dilute with a solvent with a compounding ratio (mass ratio) of toluene / methyl ethyl ketone / hexane = 1/1/18 so that the solid content becomes 3 mass%, One part by mass of the platinum-based catalyst C1 was added to obtain a release agent composition.
(3) Release film On the crosslinked resin layer 1 of the laminated polyester film obtained above, the release agent composition is reverse-gravure so that the film thickness of the release layer 1 becomes 0.2 μm offline. After coating by a coating method and heat treatment at 180 ° C. for 10 seconds, a release film was obtained.
The evaluation results of the obtained release film are shown in Table 3. The film thickness of the release layer and the cross-linked resin layer in the present invention is obtained by dyeing the release film with a heavy metal such as a ruthenium compound or osmium compound and adjusting the cross section of the release film by the ultrathin section method. The cross-linked resin layer of the cross section of the release film was randomly measured at a plurality of places with a scanning electron microscope, and the average value was calculated.

[Examples 2 to 14 and Comparative Examples 1 to 8]
A crosslinked film was produced in the same manner as in Example 1 except that the crosslinked resin layer was changed to the crosslinked resin layer shown in Table 1, and the release layer was changed to the release agent composition shown in Table 2, to obtain a release film. The
The evaluation results of the obtained release film are shown in Table 3.

[Comparative Examples 9, 10]
The crosslinked resin layer is changed to the crosslinked resin layer shown in Table 1, and the release layer is manufactured in the same manner as in Example 1 except that it is changed to the following release agent composition (release layer 17), and a release film is obtained. Obtained. The evaluation results of the obtained release film are shown in Table 3.
For the release layer 17, an addition-type cured silicone resin different from the vinyl group-containing polydimethylsiloxane and the hydrosilyl group-containing polydimethylsiloxane described above was used.
<Mold Release Agent Composition>
Addition-type cured silicone resin (KS-847H, Shin-Etsu Chemical Co., Ltd.): 20 parts by mass Addition-type platinum catalyst (CAT-PL-50T, Shin-Etsu Chemical Co., Ltd.): 0.2 parts by mass methyl ethyl ketone / toluene Mixed solvent (mixing ratio = 1: 1 (mass ratio))

The examples are good in all evaluations of peel strength as a light release release film, surface specific resistance, adhesion with time of coating film, and productivity. On the other hand, the comparative examples did not satisfy all the evaluations, and did not satisfy the evaluation criteria of the present invention, and were not practical.

The release film of the present invention can be used for various optical applications, for example, for manufacturing various display components such as a polarizing plate for liquid crystal display, a retardation plate, a plasma display component, and an organic EL component.

Claims

A release film comprising a crosslinked resin layer on at least one side of a polyester film stretched in at least one uniaxial direction, and further having a release layer laminated on the crosslinked resin layer,
The crosslinked resin layer is formed of a crosslinked resin composition containing an ionic polymer (A) having a cationic group and a crosslinking agent (C),
The release layer has a weight average molecular weight of 500 to 50,000, and a first polydimethylsiloxane having at least one alkenyl group in one molecule, and a weight average molecular weight of 120 to 20,000, in one molecule. Formed from a release agent composition containing a second polydimethylsiloxane having at least one hydrosilyl group, and
A release film having a peeling force of 4 g / 25 mm or less when measured by the following method.
<Measurement of Peeling Force> A release layer of a release film and a pressure-sensitive adhesive tape (Nitto Denko Co., Ltd., “No. 502, acrylic adhesive) are attached to each other, and the tensile speed is 300 mm / min. Conduct a 180 ° peel test.
The release film according to claim 1, wherein the ionic polymer (A) is a quaternary ammonium base-containing polymer.
The release film according to claim 1, wherein the crosslinked resin composition further contains a binder polymer (B).
The release film according to claim 3, wherein the binder polymer (B) is at least one selected from an acrylic resin and a vinyl resin.
The release film according to any one of claims 1 to 4, wherein the release agent composition further contains a platinum-based catalyst.
The release film according to any one of claims 1 to 5, wherein the release agent composition further contains a reactive group-containing organic silicon compound.
The release film according to any one of claims 1 to 6, wherein the release agent composition further contains a non-reactive silicone resin.
The release film according to any one of claims 1 to 7, wherein the thickness of the release layer is 0.01 to 1 μm.
A laminate comprising a release film having a crosslinked resin layer on at least one surface of a polyester film stretched in at least one uniaxial direction, and a release layer laminated on the crosslinked resin layer, and a double-sided adhesive sheet And
The crosslinked resin layer contains an ionic polymer (A) having a cationic group,
The release layer contains polydimethylsiloxane and has a film thickness of 0.01 to 1 μm,
The layered product whose exfoliation power of the mold release layer surface of this mold release film, and this double-sided adhesive sheet is 4 g / 25 mm or less by 180 degrees exfoliation under conditions of tensile speed 300 mm / min.