JP4322274B2 - Organopolysiloxane composition for forming peelable cured film and peelable sheet-like substrate - Google Patents

Description

  The present invention relates to an organopolysiloxane composition for forming a peelable cured film comprising a defoaming agent for a silicone-based release agent, and a peelable sheet-like substrate. Specifically, an organopolysiloxane composition for forming a peelable cured film, comprising an antifoaming agent for a silicone-based release agent that exhibits excellent antifoaming properties during high-speed coating without reducing the adhesive strength of the adhesive, and The present invention relates to a peelable sheet-like substrate obtained by applying the composition to a substrate and curing it.

Conventionally, it is known that a release film for adhesive substances can be imparted by forming a cured film of organopolysiloxane on the surface of a sheet-like substrate such as various paper materials, laminated paper, synthetic resin films, knitted fabrics, and metal foils. It has been. As such an organopolysiloxane for forming a peelable cured film, a solution type organopolysiloxane composition (see Patent Document 1) that uses an organic solvent at the time of coating, and a solventless that does not use an organic solvent at the time of coating. A type of organopolysiloxane composition (see Patent Document 2) is known. These organopolysiloxane compositions for forming a peelable cured film are usually applied to various substrates using a roll coater, but bubbles are generated because the roll rotates in the coating solution. In such a state, when the organopolysiloxane composition is applied to paper or a plastic film, pinholes are generated and cannot be applied uniformly, resulting in partial peeling. there were. In recent years, the problems caused by foaming have been that the coating bath concentration has increased due to environmental issues and economics, and the processing speed has increased, and various additives have been applied to create distinctive release papers. Since it has come to be blended into the liquid, it has become larger. In order to solve this problem, an organopolysiloxane composition for forming a peelable cured film obtained by blending a trifluoropropylmethylsiloxane / dimethylsiloxane copolymer has been proposed (see Patent Document 3). However, this composition has a drawback in that the trifluoropropylmethylsiloxane / dimethylsiloxane copolymer bleeds out to the surface of the release paper and reduces the adhesive strength of the adhesive.
Japanese Examined Patent Publication No. 46-26798 Japanese Patent Laid-Open No. 47-32072 Japanese Patent Laid-Open No. 06-25601

  An object of the present invention is to contain a defoamer for a silicone-based release agent that does not reduce the adhesive strength of an adhesive and has excellent defoaming properties at high-speed coating, and a uniform cured film at high-speed coating The cured film thus obtained has a high residual adhesion rate and good release properties, and a peelable cured film-forming organopolysiloxane composition, and the composition is applied to a substrate and cured. It is providing the peelable sheet-like base material which becomes.

（式中、Ｒ^２は二価炭化水素基であり、ｎは１〜２０の整数である。）
および
（Ｄ）付加反応用触媒 触媒量
からなる剥離性硬化皮膜形成用オルガノポリシロキサン組成物および該剥離性硬化皮膜形成用オルガノポリシロキサン組成物をシート状基材に塗布し、硬化させてなる剥離性シート状基材により上記課題を解決できることを見出し、本発明に到達した。
As a result of intensive studies to solve the above problems, the present inventors,
(A) General formula: R _a SiO _{(4-a) / 2} wherein R is a monovalent hydrocarbon group and at least 50 mol% is a methyl group. A is 1.95 to 2.05. 100 parts by weight of an organopolysiloxane having a viscosity at 25 ° C. of at least 40 centipoise and having at least two alkenyl groups in one molecule,
(B) represented by the general formula: R ¹ _b SiO _{(4-b) / 2} (wherein R ¹ is an alkyl group or a hydrogen atom, and b is a number of 1.5 to 3.0), 0.5-20 parts by weight of an alkyl hydrogen polysiloxane having a viscosity at 25 ° C. of 1 to 1,000 centipoise and having at least 3 silicon-bonded hydrogen atoms in one molecule;
(C) the viscosity at 25 ° C. is in the range of 0.1 to 10,000 poises , and at least one fluorine atom-containing organic group selected from the groups represented by the following general formula in one molecule; Having two alkenyl groups , the remaining silicon-bonded organic group is an alkyl group, an aryl group or an aralkyl group, and the content of fluorine-containing organic groups in the molecule is in the range of 1 to 70 mol%, 0.001 to 10 parts by weight of an organopolysiloxane in which the content of the alkenyl group is in the range of 1 to 40 mol%

(In the formula, R ² is a divalent hydrocarbon group, and n is an integer of 1 to 20.)
And (D) catalyst for addition reaction, a peelable cured film-forming organopolysiloxane composition comprising a catalytic amount, and a release obtained by applying and curing the peelable cured film-forming organopolysiloxane composition on a sheet-like substrate The present inventors have found that the above problems can be solved by a sheet-like base material, and have reached the present invention.

The organopolysiloxane composition for forming a peelable cured film of the present invention can be applied thinly and uniformly without generating pinholes even during high-speed coating, and can form a uniform cured film. Moreover, the obtained cured film has a high residual adhesion rate and good peeling properties. The peelable sheet-like substrate of the present invention has a uniform cured film of the composition, has a high residual adhesion rate, and has good peel properties.

（式中、Ｒ^２は二価炭化水素基であり、ｎは１〜２０の整数である。）
および
（Ｄ）付加反応用触媒 触媒量
からなる。
The organopolysiloxane composition for forming a peelable cured film of the present invention will be described in detail.
The composition of the present invention is an addition reaction curable type, and (A) General formula: R _a SiO _{(4-a) / 2} (wherein R is a monovalent hydrocarbon group and at least 50 mol% is a methyl group) A is a number from 1.95 to 2.05), an organopolysiloxane having a viscosity at 25 ° C. of at least 40 centipoise and having at least two alkenyl groups in one molecule Part,
(B) represented by the general formula: R ¹ _b SiO _{(4-b) / 2} (wherein R ¹ is an alkyl group or a hydrogen atom, and b is a number of 1.5 to 3.0), 0.5-20 parts by weight of an alkyl hydrogen polysiloxane having a viscosity at 25 ° C. of 1 to 1,000 centipoise and having at least 3 silicon-bonded hydrogen atoms in one molecule;
(C) the viscosity at 25 ° C. is in the range of 0.1 to 10,000 poises , and at least one fluorine atom-containing organic group selected from the groups represented by the following general formula in one molecule; Having two alkenyl groups , the remaining silicon-bonded organic group is an alkyl group, an aryl group or an aralkyl group, and the content of fluorine-containing organic groups in the molecule is in the range of 1 to 70 mol%, 0.001 to 10 parts by weight of an organopolysiloxane in which the content of the alkenyl group is in the range of 1 to 40 mol%

(In the formula, R ² is a divalent hydrocarbon group, and n is an integer of 1 to 20.)
And (D) catalyst for addition reaction.

Each component will be described in detail. The component (A) is represented by the general formula: R _a SiO _{(4-a) / 2} , has a viscosity of at least 40 centipoise at 25 ° C., and at least two in one molecule. It is an organopolysiloxane having the following alkenyl group. In the above formula, R is a monovalent hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a vinyl group, an allyl group, a butenyl group, a pentenyl group, or a hexenyl group, of which at least 50 mol% is a methyl group is there. a is a number from 1.95 to 2.05. Examples of the molecular structure of the organopolysiloxane include linear and branched chains, and the molecular chain terminal may be any of methyl group, vinyl group, allyl group, hydroxyl group, phenyl group and the like, and is not limited. The organopolysiloxane may have a viscosity at 25 ° C. of 40 centipoises or higher, and can be used in the form of raw rubber. This is because if it is less than 40 centipoise, the penetration into the substrate becomes excessive. When the composition of the present invention is used as a solventless type, the viscosity of this component is preferably 40 to 10,000 centipoise, more preferably 100 to 5,000 centipoise. Further, when the composition of the present invention is used as a solution type, it is preferably from 10,000 centipoise to a raw rubber-like one, more preferably from 500,000 centipoise to a raw rubber-like one. In addition, as this component, one kind of organopolysiloxane may be used alone or several kinds of mixtures may be used. Specific examples of such component (A) include dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of molecular chain, methylvinylsiloxane / dimethylsiloxane copolymer blocked with trimethylsiloxy group at both ends of molecular chain, dimethylhexenyl at both ends of molecular chain. Examples include a siloxy group-blocked methylhexenylsiloxane / dimethylsiloxane copolymer and a molecular chain both-end hydroxyl group-blocked methylvinylsiloxane / dimethylsiloxane copolymer.

Component (B) is an alkyl hydrogen polysiloxane having a viscosity at 25 ° C. of 1 to 1,000 centipoise and having at least three silicon-bonded hydrogen atoms in one molecule, and (A) component and ( C) A cross-linking agent of the component. In order to obtain a cured film by crosslinking reaction with the component (A) or the component (C), at least three silicon-bonded hydrogen atoms are required in one molecule. This component is represented by the general formula: R ¹ _b SiO _{(4-b) / 2} . In the formula, R ¹ is an alkyl group or a hydrogen atom, and the alkyl group preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and an octyl group. Among these, a methyl group is preferable. b is a number from 1.5 to 3.0. Examples of the molecular structure include straight chain, branched chain, and cyclic bodies. In the case of a straight chain or branched chain, the terminal can be a trialkylsiloxy group or a dialkylhydrogensiloxy group. The alkyl hydrogen polysiloxane has a viscosity at 25 ° C. of 1 to 1,000 centipoise, preferably 5 to 500 centipoise. This is because if it is less than 1 centipoise, it tends to volatilize, and if it exceeds 1,000 centipoise, the curing time for obtaining a cured film having suitable peeling performance becomes long. Specific examples of this component (B) include molecular chain both ends trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, molecular chain both ends dimethylhydrogensiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer. , Molecular chain both ends trimethylsiloxy group-blocked methyl hydrogen polysiloxane, cyclic methyl hydrogen polysiloxane, cyclic methyl hydrogen siloxane / dimethyl siloxane copolymer. The addition amount of this component is in the range of 0.5 to 20 parts by weight, preferably in the range of 1 to 10 parts by weight with respect to 100 parts by weight of component (A). This is because if the amount is less than 0.5 part by weight, the curing becomes insufficient, and if it exceeds 20 parts by weight, the peeling performance of the cured film is unfavorably affected.

上式中、Ｒ²は二価炭化水素基であり、具体的には、メチレン基，エチレン基，メチルエチレン基，プロピレン基，ブチレン基等のアルキレン基；フェニレン基，トリレン基，キシリレン基等のアリーレン基；メチレンフェニレン基，エチレンフェニレン基等のアルキレンアリーレン基またはアリーレンアルキレン基が例示される。ｎは１〜２０の整数である。アルケニル基として具体的には、ビニル基，アリル基，ブテニル基，ペンテニル基，ヘキセニル基が例示される。尚、このフッ素原子含有有機基の含有量は、１〜７０モル％の範囲である。アルケニル基およびケイ素原子結合水素原子の各含有量は、１〜４０モル％の範囲である。またこのオルガノポリシロキサン中の、フッ素原子含有有機基、アルケニル基およびケイ素原子結合水素原子以外のケイ素原子に結合する基はメチル基，エチル基，プロピル基，ブチル基等のアルキル基；フェニル基，トリル基，キシリル基等のアリール基；ベンジル基，フェネチル基等のアラルキル基である。これらの中でもメチル基，フェニル基が好ましい。さらにこのオルガノポリシロキサンは、少量の水酸基やアルコキシ基を有していてもよい。またその分子構造は特に限定されず、例えば、直鎖状，環状，樹脂状，一部分岐を有する直鎖状のいずれであってもよく、部分的に交叉結合を有していてもよいが、一般に、直鎖状または一部分岐を有する直鎖状のものが使用される。有機溶剤可溶性，消泡性，レベリング性から、２５℃における粘度が０.１〜１０,０００ポイズの範囲である。本成分の添加量は、（Ａ）成分１００重量部に対して、０.００１〜１０重量部の範囲である。これは、０.０００１重量部未満であると塗工浴の泡立ちが多くレベリング性が不十分となり、また２０重量部を越えると硬化皮膜の剥離性能に好ましくない影響を与えるからである。
Component (C) is a component that characterizes the composition of the present invention, and has at least one fluorine atom-containing organic group and at least two alkenyl groups in one molecule, and the remaining silicon atom-bonded organic group. Is an organopolysiloxane in which is an alkyl group, an aryl group or an aralkyl group. This organopolysiloxane is an antifoaming agent for a silicone release agent that has the effect of suppressing foaming of the coating bath during high-speed coating and not reducing the adhesive strength of the pressure-sensitive adhesive. The fluorine atom-containing organic group is a group represented by the following general formula.

In the above formula, R ² is a divalent hydrocarbon group, specifically, alkylene groups such as methylene group, ethylene group, methylethylene group, propylene group, butylene group; phenylene group, tolylene group, xylylene group, etc. An arylene group; an alkylene arylene group or an arylene alkylene group such as a methylenephenylene group and an ethylenephenylene group; n is an integer of 1-20. Specific examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, and a hexenyl group. The content of the fluorine-containing organic group, area by der of 1 to 70 mol%. Each content of alkenyl groups and silicon-bonded hydrogen atoms, area by der of 1 to 40 mol%. In the organopolysiloxane, a fluorine atom-containing organic group, an alkenyl group, and a group bonded to a silicon atom other than a silicon atom-bonded hydrogen atom are alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group; Aryl groups such as a tolyl group and a xylyl group; and aralkyl groups such as a benzyl group and a phenethyl group. Among these, a methyl group and a phenyl group are preferable. Furthermore, this organopolysiloxane may have a small amount of hydroxyl groups or alkoxy groups. The molecular structure is not particularly limited, and may be, for example, linear, cyclic, resinous, partially branched linear, or partially cross-linked, In general, a linear or partially branched one is used . Organic solvent-soluble, anti-foaming property, leveling property, area by der viscosity of 0.1 to 10,000 poise at 25 ° C.. The addition amount of the component is to 100 weight parts component (A) is in the range of 0.001 to 10 parts by weight. This is because if the amount is less than 0.0001 parts by weight, foaming of the coating bath is large and the leveling property becomes insufficient, and if it exceeds 20 parts by weight, the peelability of the cured film is adversely affected.

Specific examples of the component (C) include dimethylvinylsiloxy group-blocked methyl (3,3,3-trifluoropropyl) polysiloxane having both molecular chains, dimethylvinylsiloxy group-blocked methyl (3,3,3, both ends). 3-trifluoropropyl) siloxane / dimethylsiloxane copolymer, both ends of the molecular chain dimethylvinylsiloxy group-blocked methyl (3,3,3-trifluoropropyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer, both molecular chains Terminal dimethylvinylsiloxy group-blocked methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer, molecular chain both ends dimethylvinylsiloxy group-blocked methyl (perfluorohexylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane Both copolymer and molecular chain Trimethylsiloxy group-blocked methyl (3,3,3-trifluoropropyl) siloxane / methylvinylsiloxane copolymer, both ends of the molecular chain trimethylsiloxy group-blocked methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane Polymer, molecular chain both ends trimethylsiloxy group-blocked methyl (perfluorohexylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer, molecular chain both ends dimethylvinylsiloxy group-blocked methyl (perfluorobutylethyl) siloxane / dimethylsiloxane Copolymer, dimethylhexenylsiloxy group-capped methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer, molecular chain both-ends silanol group-capped methyl (per Fluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer, silanol group-blocked methyl (perfluorohexylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer, one end of molecular chain is silanol group Examples thereof include a methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer blocked and blocked at the other end with a trimethylsiloxy group.

  The catalyst for addition reaction of component (D) is a catalyst for crosslinking reaction of the above components (A), (B) and (C). Specific examples include chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid olefin complexes, chloroplatinic acid and vinylsiloxane complexes, chloroplatinic acid and diketones complexes, and powders on alumina or silica carriers. Examples include platinum-supported materials, palladium catalysts, and rhodium catalysts. The addition amount of this component may be a catalyst amount, and is usually such an amount that the platinum metal amount is 10 to 1,000 ppm with respect to the total amount of the components (A), (B) and (C). is there.

  The composition of the present invention comprises the above components (A) to (D), but other components such as an organic solvent, an addition reaction retarder, an adhesion improver, a dye, an inorganic filler, and a pigment as necessary. Adding and blending may be carried out as long as the object of the present invention is not impaired. Organic solvents include aromatic hydrocarbons such as toluene, xylene, benzene and trifluorotoluene; aliphatic hydrocarbons such as heptane, hexane, pentane and isooctane; halogenated hydrocarbons such as trichloroethylene and perchloroethylene; acetone and methyl ethyl ketone , Methyl acetate, and ethyl acetate. Examples of addition reaction retarders include 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-penten-3-ol, and phenylbutynol. Examples include alkynyl alcohol; 3-methyl-3-penten-1-yne, 3,5-dimethyl-1-hexyne-3-yne, benzotriazole, and methylvinylsiloxane cyclic.

  The composition of the present invention can be produced simply by uniformly mixing and dispersing the above components (A) to (D), and the order of addition of each component is not particularly limited. For example, component (A), component (B), component (C), and component (D) may be mixed at the time of use, and component (A), component (B), and component (C) are mixed in advance. The component (D) may be added and mixed at the time of use, or the component (A) and the component (B) may be mixed in advance, and the component (C) and the component (D) may be added and mixed at the time of use. Good.

Next, the peelable sheet-like substrate of the present invention will be described.
The releasable sheet-like substrate of the present invention comprises the above-described organopolysiloxane composition for forming a peelable cured film according to the present invention, using various coating materials such as gravure coating, reverse coating, and roll coating. It is applied to various sheet-like substrates such as synthetic films, laminated paper, various fibers, knitted fabrics, metal foils, etc., and then cured under conditions of a heating temperature of 50 to 200 ° C. and a heating time of 3 to 120 seconds, for example. Is obtained. In addition, the peelability as used in the field of this invention means the peelability with respect to an adhesive substance.

  Since the organopolysiloxane composition for forming a peelable cured film of the present invention as described above contains an antifoaming agent for silicone release agent (C), pinholes are generated even during high-speed coating. The cured film thus obtained is characterized by a high residual adhesive rate and excellent peeling properties.

Next, an example explains the present invention. In the examples, “part” means “part by weight”, and the viscosity is a value measured at 25 ° C. Further, foamability, presence / absence of pinholes, residual adhesion rate, and peeling resistance were measured according to the following methods.
(1) Foaming property 40 g of a sample was taken in a 100 ml glass bottle with a transparent lid having a diameter of 5 cm, shaken with a shaker for 30 minutes, and then allowed to stand for 1 minute to measure the liquid level. This height was expressed as a percentage with respect to the height of the liquid level before shaking.
(2) Presence / absence of pinholes 40 g of a sample was taken in a 100 ml glass bottle with a transparent lid with a diameter of 5 cm, shaken with a shaker for 30 minutes, and then coated on polyethylene laminated paper using a coating rod. The coating was performed so as to obtain 0.0 g / m ² . The presence or absence of pinholes on the coated surface was visually observed.
(3) Peel resistance 40 g of a sample was taken in a 100 ml glass bottle with a transparent lid with a diameter of 5 cm, shaken with a shaker for 30 minutes, and then coated on polyethylene laminated paper with a coating rod with a coating weight of 1.0 g. The coating was performed so as to be / m ² . After coating, a release paper was prepared by heat treatment at 150 ° C. for 20 seconds. On the surface of the cured film of the release paper, an acrylic solvent-type pressure-sensitive adhesive [manufactured by Toyo Ink Co., Ltd .; trade name: Orivine BPS-5127] or an acrylic emulsion-type pressure-sensitive adhesive [manufactured by Toyo Ink Co., Ltd .; 3110H] and then heat-treated at 100 ° C. for 4 minutes. Next, a laminated paper was bonded to this, and left in an atmosphere of 25 ° C. and humidity 60% under a load of 20 g / cm ² . After 24 hours, the laminated paper was pulled at an angle of 180 ° using Tensilon, and the force (gf) required for peeling was measured. Note that the width of all the test pieces was 5 cm.
(4) Residual adhesion rate 40 g of a sample was taken in a 100 ml glass bottle with a transparent lid with a diameter of 5 cm, shaken with a shaker for 30 minutes, and then coated on polyethylene laminated paper with a coating rod at a coating amount of 1. The coating was carried out so as to be 0 g / m ² . After coating, a release paper was prepared by heat treatment at 150 ° C. for 20 seconds. A polyester adhesive tape (manufactured by Nitto Denko Corporation; trade name 31B tape) was bonded to the cured film surface of the release paper, and heat-treated at 70 ° C. for 20 hours while applying a load of 20 g / cm ² . After the heat treatment, the polyester adhesive tape was peeled off from the cured film and attached to a stainless steel plate. Next, this test piece was pulled at an angle of 180 ° at a peeling speed of 0.3 m / min, and the force (gf) required for peeling was measured. The force required for this peeling was expressed as a percentage of the force required for peeling the untreated standard tape.

[Example 1]
100 parts of dimethylsiloxane / methylvinylsiloxane copolymer with a dimethylvinylsiloxy group blocked at both ends of a raw rubber-like molecular chain (vinyl group content 0.7% by weight), and a methylhydrogen blocked with a trimethylsiloxy group at both ends of a molecular chain having a viscosity of 20 centipoise 6 parts of polysiloxane (content of silicon atom-bonded hydrogen atoms 1.6% by weight) and 1 part of 3-methyl-1-butyn-3-ol are mixed with toluene so that the total weight becomes 1,060 parts. Diluted and dissolved. Subsequently, a dimethylvinylsiloxy group-blocked methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer [methyl (perfluorobutylethyl) siloxane unit 40 mol%, methyl Vinyl siloxane unit 1.0 mol%, vinyl group content 0.2 wt%] with respect to 100 parts of the raw rubber-like molecular chain-terminated dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer. Samples 1 to 5 were added with 0.001 part, 0.01 part, 0.1 part, 1.0 part, and 2.0 part, respectively. An organopolysiloxane composition for forming a peelable cured film according to the present invention was prepared by adding a complex of chloroplatinic acid and divinyltetramethyldisiloxane in an amount of 500 ppm as platinum metal to these samples. With respect to the organopolysiloxane composition for forming a peelable cured film thus obtained, foamability, presence / absence of pinholes, peel resistance and residual adhesion rate were measured. The measurement results are shown in Table 1.

[Comparative Example 1]
In Example 1, the same procedure as in Example 1 was performed except that a dimethylvinylsiloxy group-blocked methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer having a viscosity of 650 poise was added. Then, an organopolysiloxane composition for forming a peelable cured film was prepared (Sample 6). The resulting peelable cured film-forming organopolysiloxane composition was measured for foamability, presence / absence of pinholes, peel resistance and residual adhesion rate. The measurement results are shown in Table 1.

[Comparative Example 2]
In Example 1, instead of a methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer blocked at both ends of a molecular chain having a viscosity of 650 poise with a dimethylvinylsiloxy group, trimethylsiloxy at both ends of a molecular chain having a viscosity of 500 poise. Peelable curing in the same manner as in Example 1 except that 1.0 part of a base-blocked methyl (perfluorobutylethyl) siloxane / dimethylsiloxane copolymer [methyl (perfluorobutylethyl) siloxane unit 45 mol%] was added. An organopolysiloxane composition for film formation was prepared (Sample 7). The resulting peelable cured film-forming organopolysiloxane composition was measured for foamability, presence / absence of pinholes, peel resistance and residual adhesion rate. The measurement results are shown in Table 1.

[Example 3]
100 parts by weight dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer having a viscosity of 300 centipoise (1.0% by weight vinyl group content), 20 parts centipoise molecular chain at both ends by trimethylsiloxy group-blocked methylhydro 5 parts of Genpolysiloxane (silicon atom-bonded hydrogen atom content 1.6% by weight) and 1.0 part of 3-methyl-1-butyn-3-ol were mixed. Next, a dimethylvinylsiloxy group-blocked methyl (3,3,3-trifluoropropyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer [3,3,3-trifluoropropyl] having a viscosity of 600 poise and a molecular chain at both ends is added. 40 mol% of siloxane units and 0.4 wt% of vinyl group] were each added to 100 parts of the dimethylsiloxane siloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer having a viscosity of 300 centipoise. Samples 15 to 19 were prepared by adding 001 parts, 0.01 parts, 0.1 parts, 1.0 parts, and 2.0 parts. An organopolysiloxane composition for forming a peelable cured film was prepared by adding a complex of chloroplatinic acid and divinyltetramethyldisiloxane in an amount of 500 ppm as platinum metal to these samples. With respect to the organopolysiloxane composition for forming a peelable cured film thus obtained, foamability, presence / absence of pinholes, peel resistance and residual adhesion rate were measured. The measurement results are shown in Table 3.

[Comparative Example 5]
Example 3 Example 3 except that the molecular chain both ends dimethylvinylsiloxy group-blocked methyl (3,3,3-trifluoropropyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer having a viscosity of 600 poise was not added. In the same manner as in No. 3, an organopolysiloxane composition for forming a peelable cured film was prepared (Sample 20). The resulting peelable cured film-forming organopolysiloxane composition was measured for foamability, presence / absence of pinholes, peel resistance and residual adhesion rate. The measurement results are shown in Table 3.

[Comparative Example 6]
In Example 3, instead of a dimethylvinylsiloxy group-blocked methyl (3,3,3-trifluoropropyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer having a viscosity of 600 poise at both ends, a molecule having a viscosity of 500 poise 1.0 part of methyl (3,3,3-trifluoropropyl) siloxane / dimethylsiloxane copolymer [methyl (3,3,3-trifluoropropyl) siloxane unit 40 mol%] blocked with trimethylsiloxy groups at both chain ends Except for the addition, an organopolysiloxane composition for forming a peelable cured film was prepared in the same manner as in Example 3 (Sample 21). The resulting peelable cured film-forming organopolysiloxane composition was measured for foamability, presence / absence of pinholes, peel resistance and residual adhesion rate. The measurement results are shown in Table 3.

Claims (2)

(A) General formula: R _a SiO _{(4-a) / 2} wherein R is a monovalent hydrocarbon group and at least 50 mol% is a methyl group. A is 1.95 to 2.05. 100 parts by weight of an organopolysiloxane having a viscosity at 25 ° C. of at least 40 centipoise and having at least two alkenyl groups in one molecule,
(B) represented by the general formula: R ¹ _b SiO _{(4-b) / 2} (wherein R ¹ is an alkyl group or a hydrogen atom, and b is a number of 1.5 to 3.0), 0.5-20 parts by weight of an alkyl hydrogen polysiloxane having a viscosity at 25 ° C. of 1 to 1,000 centipoise and having at least 3 silicon-bonded hydrogen atoms in one molecule;
(C) the viscosity at 25 ° C. is in the range of 0.1 to 10,000 poises , and at least one fluorine atom-containing organic group selected from the groups represented by the following general formula in one molecule; Having two alkenyl groups , the remaining silicon-bonded organic group is an alkyl group, an aryl group or an aralkyl group, and the content of fluorine-containing organic groups in the molecule is in the range of 1 to 70 mol%, 0.001 to 10 parts by weight of an organopolysiloxane in which the content of the alkenyl group is in the range of 1 to 40 mol%

(In the formula, R ² is a divalent hydrocarbon group, and n is an integer of 1 to 20.)
And (D) Addition reaction catalyst An organopolysiloxane composition for forming a peelable cured film comprising a catalytic amount. The above component (C) is a dimethylvinylsiloxy group-blocked methyl (perfluorobutylethyl) siloxane / dimethylsiloxane / methylvinylsiloxane copolymer with a molecular chain at both ends or a dimethylvinylsiloxy group-blocked methyl with a molecular chain at both ends (3.3 The organopolysiloxane composition for forming a peelable cured film according to claim 1, which is a copolymer of (1,3-trifluoropropyl) siloxane / dimethylsiloxane / methylvinylsiloxane.