TWI877277B - Curable organopolysiloxane composition, release coating consisting it, and laminated body - Google Patents

Abstract

The present invention provides a peelable hardened film-forming hardening organic polysiloxane composition that forms a hardened film with excellent peeling performance without reducing the adhesiveness of sticky substances, a peeling coating agent composed of the composition, and a laminate. The present invention relates to a hardening organic polysiloxane composition and its use as a related peeling coating agent, the hardening organic polysiloxane composition containing: (A) a liquid or plastic rubber-like chain organic polysiloxane with a viscosity of 1,000,000 mPa･s or more, having alkenyl groups only on the molecular side chains, (B) a viscosity of 1,000 mPa･s or less, a chain organic polysiloxane having alkenyl groups only on the molecular side chains, (C) an organic hydropolysiloxane having two or more silicon-atom-bonded hydrogen atoms (Si-H) in one molecule, and (D) a hydrosilylation reaction catalyst, wherein the mass ratio {(A)/(B)} of the component (A) to the component (B) is in the range of 95/5 to 5/95.

Description

Curable organopolysiloxane composition, stripping coating agent and laminate composed thereof

The present invention relates to a curable organopolysiloxane composition, specifically to a peelable hardened film-forming curable organopolysiloxane composition which does not reduce the adhesiveness of a viscous substance and forms a hardened film having very excellent peeling performance, a peelable coating agent composed of the same, and a laminate.

As a peelable hardened film-forming organic silicon composition for forming a hardened film having excellent peeling performance against sticky substances, an addition reaction type organic silicon composition composed of an organic silicon containing an olefin group, an organic hydrogen polysiloxane and a platinum catalyst, and further adding a reaction inhibitor, has been widely used. Patent documents 1 to 3 propose an organic silicon composition for peelable hardened film formation, which is formed by adding an organic silicon containing no olefin group such as dimethylsiloxane rubber and dimethylsiloxane-methylphenylsiloxane copolymer to these components to improve the relevant performance. However, these compositions have the following disadvantages: the adhesion of the viscous substance is reduced, or the transfer of organic silicon causes the printability of the back of the film to be reduced; and they may not necessarily meet certain applications.

To solve these problems, Patent Document 4 proposes to reduce the stripping resistance by mixing two high molecular weight siloxanes, wherein the high molecular weight siloxane has a functional group selected from the group consisting of hydroxyl, alkenyl and alkyl at the end of the molecular chain, and the viscosity of a 30 wt% toluene solution at 25°C is 500 centistokes or more; however, in recent years, the stripping performance (especially the effect of reducing the stripping resistance) required for the stripping layer is higher, and as a stripping coating agent in recent years, it may not be able to meet the required level. In addition, since the two high molecular weight siloxanes are mixed, the viscosity of the composition becomes higher, so a composition with better operability (operability) is required.

In addition, Patent Document 5 proposes a peeling composition comprising a high molecular weight siloxane having a vinyl group at the end and a degree of polymerization of the siloxane unit in the range of 3,000 to 20,000 and a siloxane having a viscosity of 0.1 to 500 Pa·s at 25°C; it is confirmed that the adhesion to the substrate is improved, but the performance is not sufficient to achieve the problem of light peeling properties for sticky substances, and the related problem cannot be solved.

Furthermore, Patent Document 6 proposes a peeling composition comprising two siloxanes with viscosities of 50 to 10,000 mPa･s and 100,000 mPa･s or more; although the purpose of imparting lubricity to the hardened film can be achieved, similarly to the above, the performance is not sufficient to achieve the problem of light peeling properties for viscous substances, and the related problem cannot be solved. Known Technical Documents Patent Documents

Patent document 1: Japanese Patent Publication No. 53-28943 Patent document 2: Japanese Patent Publication No. 2-145650 Patent document 3: Japanese Patent Publication No. 3-52498 Patent document 4: Japanese Patent Publication No. 9-125004 Patent document 5: Japanese Patent Publication No. 2004-190202 Patent document 6: Japanese Patent Publication No. 61-159480

Invent the problem you want to solve

The present invention is developed to solve the above-mentioned problems, and its purpose is to provide a curable organic polysiloxane composition that can form a peelable hardened film that is consistent with the high peeling performance requirements required by the market in recent years, and can also take into account the peelable hardened film-forming curable organic polysiloxane composition that inhibits the reduction of the adhesion of adhesive substances. Furthermore, the purpose of the present invention is to provide the use of the composition, specifically a peelable coating and a peelable adhesive tape/film composed of the composition, which has a peeling layer and an adhesive layer laminated body using the above-mentioned composition. Technical means to solve the problem

After intensive research, the inventors of the present invention have found that the above-mentioned problems can be solved by using the following curable organopolysiloxane composition, thereby completing the present invention. The curable organopolysiloxane composition comprises: (A) a liquid with a viscosity of 1,000,000 mPa·s or more at 25°C or a rubbery state with plasticity at 25°C, and a chain organopolysiloxane having alkenyl groups with 2 to 12 carbon atoms only on the side chains of the molecule; (B) a olefinic hydrocarbon with a viscosity of 1,000,000 mPa·s or more at 25°C; mPa･s or less, a chain organic polysiloxane having only alkenyl groups with 2 to 12 carbon atoms on the molecular side chain, (C) an organic hydropolysiloxane having two or more silicon-atom-bonded hydrogen atoms (Si-H) in one molecule, and (D) a hydrosilylation reaction catalyst; and the mass ratio {(A)/(B)} of the component (A) to the component (B) is in the range of 95/5 to 5/95.

In the present invention, plasticity is plasticity measured by a plastometer according to the method specified in JIS K 6249, and specifically is a value (unit: mm) when a load of 1 kgf is applied to a 4.2 g spherical sample at 25°C for 3 minutes.

The curable organopolysiloxane composition of the present invention preferably has a mass ratio of component (A) to component (B) {(A)/(B)} in the range of 90/10 to 10/90. In addition, the composition preferably has a mass ratio of component (A) to component (B) {(A)/(B)} in the range of 70/30 to 30/70, and the molar ratio of SiH groups in component (C) is 0.5 to 5 relative to the total molar number of alkenyl groups in components (A) and (B).

The curable organopolysiloxane composition of the present invention is preferably a linear organopolysiloxane in which component (A) and component (B) have only alkenyl groups with 4 to 12 carbon atoms on the side chains of the molecules, the vinyl (CH ₂ =CH-) portion of the alkenyl groups is 0.5 to 3.0% by mass, and the molecular chain ends are capped with trialkylsilyl groups.

In the curable organopolysiloxane composition of the present invention, (E) an organic solvent is an optional component, and the composition may contain an organic solvent or may not contain an organic solvent. The composition of the present invention may be in any form including (E) an organic solvent, such as a solution and a suspension, and preferably a solution.

The curable organopolysiloxane composition of the present invention may further contain (F) a hydrosilylation reaction inhibitor and may also contain (G) a photopolymerization initiator.

The curable organopolysiloxane composition of the present invention can be used as a stripping coating agent.

The problem of the present invention can be solved by a sheet-like article having a hardened layer formed by hardening the hardening organopolysiloxane composition of the present invention and a sheet-like substrate. The hardened layer is preferably a peelable hardened film.

In addition, the problem of the present invention can be solved by a laminate having a structure in which an adhesive layer and at least one peeling layer are arranged opposite to each other, and the peeling layer is a peeling layer composed of a hardened material formed by hardening a peeling coating composed of the curable organic polysiloxane composition of the present invention. Effect of the invention

The curable organopolysiloxane composition is coated on a sheet-like substrate, such as a substrate film, and cured to obtain a peeling sheet. In the peeling sheet, the peeling layer composed of the composition has excellent peeling performance for viscous substances and can inhibit the decrease in the adhesiveness of the viscous substances. In addition, a peeling coating composed of the composition of the present invention can be provided. Similarly, a peeling adhesive tape/sheet can be provided, which has a laminated body of a peeling layer and an adhesive layer using the above-mentioned composition.

Specifically, the peelable sheet obtained by using the curable organopolysiloxane composition of the present invention in the peeling layer has excellent peeling properties relative to the relevant viscous substances. Specifically, when the viscous substance is applied on the surface of the hardened layer obtained by curing the curable organopolysiloxane composition of the present invention, the resistance when the peelable sheet is peeled off from the applied viscous substance can be reduced during drying and curing.

The peelable sheet having a hardened layer obtained by hardening the curable organopolysiloxane composition of the present invention and the peelable sheet for adhesive substances of the present invention have excellent coating properties on plastic films. Specifically, when the curable organopolysiloxane composition of the present invention, i.e., the peeling agent composition, is coated on the plastic film, the surface of the plastic film does not shrink during drying and curing, and the peelable sheet can be evenly coated to obtain a peelable sheet having a uniform appearance.

Furthermore, the peelable sheet having a hardened layer obtained by hardening the curable organopolysiloxane composition of the present invention is excellent in maintaining the adhesive force of the adhesive substance. Specifically, the adhesive substance is applied on the surface of the hardened layer obtained by hardening the curable organopolysiloxane composition of the present invention, dried and hardened, and the adhesive force of the adhesive substance does not decrease after the hardened layer (peelable layer) is peeled off from the applied adhesive substance, and can be maintained at the original level.

The curable organopolysiloxane composition of the present invention comprises: (A) a liquid having a viscosity of 1,000,000 mPa･s or more at 25°C or a rubbery state having plasticity at 25°C, wherein only the side chains of the molecule have alkenyl groups with carbon atoms of 2 to 12; (B) a mPa･s or less, a chain organic polysiloxane having only alkenyl groups with 2 to 12 carbon atoms on the molecular side chain, (C) an organic hydropolysiloxane having two or more silicon-atom-bonded hydrogen atoms (Si-H) in one molecule, and (D) a hydrosilylation reaction catalyst, wherein the mass ratio of the component (A) to the component (B) {(A)/(B)} is in the range of 95/5 to 5/95, and optionally contains (E) an organic solvent and/or (F) a hydrosilylation reaction inhibitor, and in a particularly preferred embodiment, may contain (G) a photopolymerization initiator. The following is a detailed description of the components of the curable organopolysiloxane composition and the peeling sheet made using the composition of the present invention, namely, the sheet for peeling adhesive substances.

The viscosity of organopolysiloxane at 25°C described in this manual is the value measured by a rotational viscometer. In addition, the plasticity is the plasticity measured by a plastometer according to the method specified in JIS K 6249, and is specifically the value (unit: mm) when a load of 1 kgf is applied to a 4.2g spherical sample at 25°C for 3 minutes.

[Component (A)] In the present invention, component (A) is a so-called high-polymerization degree organopolysiloxane or an organopolysiloxane mixture, and its physical property range continuously involves a region showing a high viscosity liquid to a region showing a plastic rubber state due to an increase in its polymerization degree. That is, due to an increase in the degree of polymerization of the organopolysiloxane, if the viscosity at 25°C exceeds 15,000,000 mPa･s, its viscosity is generally difficult to measure, and it shifts from a region showing a higher viscosity (liquid state) to a region where its physical properties can be determined by plasticity (rubber state).

That is, the component (A) of the present invention is a liquid having a viscosity of 1,000,000 mPa·s or more at 25°C, and also includes a rubbery organic polysiloxane or an organic polysiloxane mixture, which includes a region with a higher degree of polymerization, where the viscosity at 25°C is difficult to measure, and the region of the degree of polymerization, etc., where the physical properties should be determined by plasticity. It is particularly preferred that the component (A) is a liquid having a viscosity of 1,000,000 mPa·s or more at 25°C, or a rubbery organic polysiloxane or an organic polysiloxane mixture having a plasticity of 3.0 mm or less at 25°C. It is most preferred that the component (A) is a rubbery organic polysiloxane or an organic polysiloxane mixture having a plasticity of 0.5 to 3.0 mm at 25°C.

One of the characteristics of the invention is that component (A) is a chain-shaped organic polysiloxane having alkenyl groups with 2 to 12 carbon atoms only on the molecular side chain, and no reactive functional groups such as alkenyl groups are present at the molecular chain ends. When alkenyl groups are present at the molecular chain ends, the technical effects of the invention, namely, the effects of both high peeling properties and inhibition of the decrease in adhesion of viscous materials, may not be achieved.

Component (A) is preferably a linear organic polysiloxane having only alkenyl groups with 2 to 12 carbon atoms in the molecular side chain, wherein the vinyl (CH ₂ =CH-) portion of the alkenyl group is 0.5 to 3.0% by mass, and the molecular chain terminal is capped with a trialkylsilyl group.

More preferably, component (A) is a linear organic polysiloxane having only hexenyl groups as alkenyl groups having 2 to 12 carbon atoms on the molecular side chain and having trimethylsiloxy groups at both ends of the molecular chain. It is particularly preferred that the functional groups other than hexenyl groups in component (A) are substantially limited to methyl groups or phenyl groups.

Component (A) can be selected from organic polysiloxane, branched organic polysiloxane and linear or branched organic polysiloxane containing a partial ring structure, but in view of industrial properties, linear organic polysiloxane represented by the following chemical formula (1) is preferred.

In formula (1), ^R1 is independently an alkyl group having 1 to 20 carbon atoms (such as methyl group, etc.) or an aryl group having 6 to 22 carbon atoms (such as phenyl group, etc.) which is unsubstituted or substituted by a halogen atom. ^R2 is independently a group selected from ^R1 or a hydroxyl group, preferably ^R1 . ^R3 is an alkenyl group having 2 to 12 carbon atoms. m is a number greater than 0, n is a number greater than 1, and m+n is a number within the range of the organopolysiloxane represented by formula (1) having a viscosity of 1,000,000 mPa·s or more at 25°C in a liquid state or having plasticity at 25°C in a rubber state. In addition, m, n, R ¹ , R ² and R ³ are preferably such that the content of the vinyl (CH ₂ =CH-) moiety in the alkenyl group having 2 to 12 carbon atoms in the organopolysiloxane molecule represented by the above formula (1) is 0.5 to 3.0 mass %.

For example, when R ³ in formula (1) is an alkenyl group having 2 to 12 carbon atoms, the content of the vinyl (CH ₂ =CH-) moiety in the alkenyl group is represented by the following formula: (molecular weight of the vinyl moiety of R ³ : about 27)×m/total molecular weight×100 (mass %), and component (A) is an organic polysiloxane satisfying the condition that the content of the vinyl (CH ₂ =CH-) moiety in the alkenyl group having 2 to 12 carbon atoms in formula (1) is in the range of 0.5 to 3.0 mass %, preferably in the range of 0.5 to 2.0 mass %.

If the content of the vinyl moiety in the alkenyl group in component (A) is lower than the above lower limit, the curing reactivity is significantly reduced, which may lead to an increase in the amount of organic silicon polymer transferred to the viscous material, a decrease in the adhesion of the viscous material, or difficulty in peeling the peeling sheet from the viscous material. On the other hand, if the content of the vinyl moiety in the alkenyl group exceeds the above upper limit, it may be difficult to peel the viscous material from the curing layer. In addition, if the viscosity or plasticity of component (A) deviates from the above range, the expected effect of reducing the peeling resistance of the present invention may not be obtained.

Furthermore, in the component (A), m+n in the formula (1) is a number within the range from the region where the organopolysiloxane represented by the formula (1) is in a high viscosity liquid state to the region where it is in a plastic rubber state, and is preferably a number of organopolysiloxanes in a liquid state having a viscosity of 1,000,000 mPa·s or more at 25°C or a number of organopolysiloxanes in a rubber state having a plasticity of 3.0 mm or less at 25°C.

More specifically, component (A) is preferably a linear organic polysiloxane represented by the following chemical formula (2), i.e., a linear organic polysiloxane having hexenyl groups as alkenyl groups with 2 to 12 carbon atoms only on the side chains of the molecule, wherein the content of the vinyl (CH ₂ =CH-) moiety in the hexenyl groups is in the range of 0.5 to 3.0 mass %, and the molecular chain is terminated by trimethylsiloxy groups at both ends. Chemical formula 2 (In formula (2), m1 is a number greater than or equal to 0, and n1 is a positive number, wherein n1 is a number in the range of 0.5 to 3.0 mass % of the content of the vinyl group (CH ₂ =CH-) in the hexenyl group (-(CH ₂ ) ₄ CH=CH ₂ ) in the molecule represented by formula (2), and more preferably a number in the range of 0.5 to 2.0 mass %. Furthermore, m1 + n1 is a number in the range of the region where the organopolysiloxane represented by formula (2) is in a high-viscosity liquid state to a region where it is in a plastic rubber state, and more preferably a number for an organopolysiloxane in a liquid state having a viscosity of 1,000,000 mPa·s or more at 25°C, or a number for an organopolysiloxane in a rubber state having a plasticity of 3.0 mm or less at 25°C.

The viscosity of component (A) at 25°C is liquid or rubbery (viscosity is usually 10,000,000 mPa･s or more, and is a semi-solid high-polymerization organic silicone polymer with plasticity). As described above, the preferred component (A) of the present invention, i.e., a high-polymerization organic polysiloxane or an organic polysiloxane mixture, has a range of physical properties that continuously ranges from a high-viscosity liquid to a plastic rubbery region due to an increase in its degree of polymerization. That is, when the degree of polymerization of the organic polysiloxane increases, if the viscosity at 25°C exceeds 15,000,000 mPa･s, its viscosity is generally difficult to measure, and it shifts from a region with a higher viscosity (liquid) to a region where its physical properties can be determined by plasticity (rubbery).

There is no upper limit to the viscosity of component (A) at 25°C. To avoid difficulties in use, it is preferred that the viscosity at 25°C be 1,000,000 mPa･s or more in a liquid state, or the plasticity at 25°C be 3.0 mm or less in a rubber state.

Component (A) may be a mixture of two or more different components (A). In addition, even a liquid organopolysiloxane having a viscosity of less than 1,000,000 mPa·s at 25°C, or a rubber organopolysiloxane having a plasticity of more than 3.0 mm at 25°C, may be used in the form of a mixture with other organopolysiloxanes, and such implementation is also within the scope of the present invention.

Component (A) is a mixture of two or more organopolysiloxanes. When the mixture as a whole is rubbery, its plasticity (plasticity measured by a plastometer according to the method specified in JIS K 6249: the value when a load of 1 kgf is applied to a 4.2 g spherical sample at 25°C for 3 minutes) is preferably in the range of 0.5 to 10.0 mm, and more preferably in the range of 0.5 to 3.0 mm.

[Component (B)] Component (B) is a liquid with a viscosity of 1,000 mPa･s or less at 25°C, and is a chain-like organic polysiloxane having only alkenyl groups with 2 to 12 carbon atoms on the side chains of the molecules. The viscosity of component (B), i.e., the degree of polymerization of siloxane, is significantly different from that of component (A), but in that the molecular chain ends do not have reactive functional groups such as alkenyl groups, components (A) and (B) have a common structure. When the molecular chain ends have alkenyl groups, the technical effect of the present invention, i.e., the effect of both achieving high peeling properties and suppressing the decrease in adhesion of viscous substances, may not be achieved.

Component (B) is preferably a linear organic polysiloxane having only alkenyl groups with 2 to 12 carbon atoms in the molecular side chain, wherein the vinyl (CH ₂ =CH-) portion of the alkenyl group is 0.5 to 3.0% by mass, and the molecular chain terminal is capped with a trialkylsilyl group.

Component (B) can be selected from linear organic polysiloxane, branched organic polysiloxane and linear or branched organic polysiloxane containing a partial ring structure, but in view of industrial properties, linear organic polysiloxane represented by the following chemical formula (3) is preferred.

In formula (3), R ¹¹ is independently an alkyl group having 1 to 20 carbon atoms (such as methyl group, etc.) or an aryl group having 6 to 22 carbon atoms (such as phenyl group, etc.) which is unsubstituted or substituted by a halogen atom. R ¹² is independently a group selected from R ¹¹ or a hydroxyl group, preferably R ¹¹ . R ¹³ is an alkenyl group having 2 to 12 carbon atoms. m' is a number greater than 0, n' is a number greater than 1, and m'+n' is a number within the range of 1,000 mPa･s or less of the viscosity of the organopolysiloxane represented by formula (3) at 25°C. In addition, m', n', R ¹¹ , R ¹² and R ¹³ are preferably such that the content of the vinyl (CH ₂ =CH-) moiety in the alkenyl group having 2 to 12 carbon atoms in the organopolysiloxane molecule represented by the above formula (3) is 0.5 to 3.0 mass %.

For example, when ^R13 in formula (3) is an alkenyl group having 2 to 12 carbon atoms, the content of the vinyl ( _CH2 =CH-) moiety in the alkenyl group is represented by the following formula: (molecular weight of the vinyl moiety of ^R13 : about 27)×m/total molecular weight×100 (mass %), and component (B) is an organic polysiloxane satisfying the condition that the content of the vinyl ( _CH2 =CH-) moiety in the alkenyl group having 2 to 12 carbon atoms in formula (3) is in the range of 0.5 to 3.0 mass %, preferably in the range of 0.5 to 2.0 mass %.

If the content of the vinyl moiety in the alkenyl group in component (B) is less than the above lower limit, the curing reactivity is significantly reduced, which may result in an increase in the amount of the organic silicon polymer transferred to the viscous material, a decrease in the adhesion of the viscous material, or difficulty in peeling the peeling sheet from the viscous material. On the other hand, if the content of the vinyl moiety in the alkenyl group exceeds the above upper limit, it may be difficult to peel the viscous material from the peeling layer obtained by curing.

In the component (B), m'+n' in the formula (3) is a range where the viscosity of the organopolysiloxane represented by the above formula (3) is less than 1,000 mPa･s at 25°C and is in a liquid state, preferably in the range of 5 to 500 mPa･s. If the viscosity of the component (B) exceeds 1,000 mPa･s, even if it is used in combination with the component (A), the expected effect of reducing the peeling resistance of the present composition may not be obtained.

More specifically, component (B) is preferably a linear organic polysiloxane represented by the following chemical formula (4), i.e., a linear organic polysiloxane having hexenyl groups as alkenyl groups having 2 to 12 carbon atoms only on the side chains of the molecule, wherein the content of the vinyl (CH ₂ =CH-) moiety in the hexenyl groups is in the range of 0.5 to 3.0 mass %, and both ends of the molecular chain are capped with trimethylsiloxy groups.

Chemical formula 4 (In formula (4), m1' is a number greater than or equal to 0, n1' is a positive number, and n1' is a number in the range of 0.5 to 3.0 mass %, preferably 0.5 to 2.0 mass % of the content of the vinyl (CH ₂ =CH-) moiety in the hexenyl (-(CH ₂ ) ₄ CH=CH ₂ ) moiety in the molecule represented by formula (4). Furthermore, m1'+n1' is preferably a number in the range of 1,000 mPa･s or less at 25°C for the viscosity of the organopolysiloxane represented by formula (4).

Component (B) may be a mixture of two or more different components (B). In addition, even an organic polysiloxane having a viscosity exceeding 1,000 mPa·s at 25°C may be used in the form of a mixture with other organic polysiloxanes, and such an implementation is also within the scope of the present invention.

If component (B) is a mixture of two or more organopolysiloxanes, the viscosity of the mixture at 25°C is 1,000 mPa･s or less, preferably in the range of 5 to 500 mPa･s.

[Mass ratio of component (A) to component (B) {(A)/(B)}] The present invention uses component (A) and component (B) having similar siloxane structures but with greatly different viscosities (siloxane polymerization degrees) in a specific mass ratio range, thereby achieving both excellent peeling properties and the technical effect of suppressing the reduction of the adhesion of sticky substances.

Specifically, the mass ratio of component (A) to component (B) {(A)/(B)} is preferably in the range of 95/5 to 5/95, more preferably in the range of 90/10 to 10/90, and particularly preferably in the range of 70/30 to 30/70. If the mass ratio (A)/(B) is greater than 95/5, the peeling resistance cannot be reduced to a sufficient level, and it may be difficult to peel off the self-adhesive material of the peeling sheet. In addition, if the mass ratio (A)/(B) is less than 5/95, it is difficult to evenly apply it on a thin sheet substrate such as a plastic film, which may result in a poor appearance of the peeling sheet.

[Component (C)] Component (C) is an organic hydropolysiloxane having two or more silicon-bonded hydrogen atoms (Si-H) in one molecule, and is a crosslinker for the above-mentioned components (A) and (B). Component (C) preferably has at least three silicon-bonded hydrogen atoms in one molecule, and the bonding position of the hydrogen atom in the molecule is not particularly limited. In addition, in addition to hydrogen atoms, the organic group contained in component (C) that is bonded to the silicon atom may be an alkyl group such as methyl, ethyl, propyl, butyl, and octyl, preferably a methyl group. In addition, the molecular structure of the organic hydropolysiloxane as component (C) may be any one of a straight chain, a branched chain, and a branched ring, or a combination of one or more of these. Furthermore, the number of hydrogen atoms bonded to a silicon atom in one molecule is an average value for all molecules.

The viscosity of component (C) at 25°C is 1 to 1,000 mPa･s, preferably 5 to 500 mPa･s. The reason is that if the viscosity of component (C) at 25°C is less than 1 mPa･s, component (C) is easily volatilized from the curable organopolysiloxane composition containing it, and if it exceeds 1,000 mPa･s, the curing time of the curable organopolysiloxane composition will be extended.

Such component (C) is not particularly limited, and examples thereof include dimethylsiloxane-methylhydrosiloxane copolymers having both ends capped with trimethylsiloxy groups, dimethylsiloxane-methylhydrosiloxane copolymers having both ends capped with dimethylhydrosiloxy groups, dimethylpolysiloxane having both ends capped with dimethylhydrosiloxy groups, methylhydropolysiloxane having both ends capped with trimethylsiloxy groups, cyclomethylhydropolysiloxane, and cyclomethylhydrosiloxane-dimethylsiloxane copolymers. Component (C) is one type of organic hydropolysiloxane or a mixture of two or more types of organic hydropolysiloxanes represented by the following general formula (5), which can form a hardened organic polysiloxane layer by undergoing an addition reaction (hydrosilylation reaction) with the silicon atom-bonded alkenyl groups contained in components (A) and (B). Chemical formula 5

In formula (5), R ²¹ is an unsubstituted or substituted alkyl or aryl group, preferably an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a phenyl group. R ²² is independently a group represented by R ¹² or a hydrogen atom (-H). When q=0, R ²² is a hydrogen atom (-H). p and q are numbers greater than 0, and p+q is a number in the range of 1 to 1,000 mPa･s of the viscosity of the organopolysiloxane represented by formula (5) at 25°C.

The mixing amount of component (C) in the curable organopolysiloxane composition of the present invention is an amount in which the molar ratio of SiH groups is 0.5 to 5.0, preferably 1.0 to 3.0, relative to the total molar number of alkenyl groups (including vinyl groups consisting of carbon-carbon double bonds) in components (A) and (B). If the molar ratio is less than the lower limit, the curability of the obtained curable organopolysiloxane composition will be reduced; if it exceeds the upper limit, the peeling resistance of the peeling layer obtained by curing to the sticky material will increase, and practical peeling properties may not be obtained.

[Component (D)] Component (D) is a hydrosilylation catalyst, which is a catalyst that promotes the addition reaction (hydrosilylation reaction) between silicon atoms bonded to alkenyl groups and silicon atoms bonded to hydrogen atoms in the curable organopolysiloxane composition. A preferred hydrosilylation catalyst is a hydrosilylation catalyst containing a platinum metal, specifically, chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid olefin complex, chloroplatinic acid and ketone complex, chloroplatinic acid and vinyl siloxane complex, platinum tetrachloride, platinum powder, aluminum oxide or dioxane. Solid platinum, platinum black, platinum olefin complex, platinum olefin siloxane complex, platinum carbonyl complex, and platinum catalysts such as thermoplastic organic resin powders such as methyl methacrylate resin, polycarbonate resin, polystyrene resin, and silicone resin are supported on a silicon oxide carrier. Platinum olefin siloxane complexes such as chloroplatinic acid and divinyltetramethyldisiloxane complex, chloroplatinic acid and tetramethyltetravinylcyclotetrasiloxane complex, platinum divinyltetramethyldisiloxane complex, and platinum tetramethyltetravinylcyclotetrasiloxane complex are particularly preferably used.

The amount of component (D) added to the curable organopolysiloxane composition is a catalytic amount. Generally, the amount of platinum metal contained in component (D) is preferably in the range of 1 to 1,000 ppm, and more preferably in the range of 5 to 500 ppm, relative to the total amount of components (A) to (C) of the curable organopolysiloxane composition of the present invention.

[Other components (E) to (G) and overall viscosity of the composition] The curable organopolysiloxane composition of the present invention can optionally contain (E) an organic solvent. The curable organopolysiloxane composition of the present invention contains a relatively large amount of component (A). Therefore, in order to achieve good workability and coating properties, it is preferred to disperse or dissolve the composition containing components (A) to (D) in a well-known (E) organic solvent for use. Without violating the purpose of the present invention, the components (A) to (D) may be dispersed or dissolved in any low-viscosity liquid organopolysiloxane other than an organic solvent (e.g., a chain or cyclic organopolysiloxane having a viscosity as low as 0.5 to 10 mPa·s at 25°C) for use. The organic solvent may be, for example, aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, octane and isoalkane, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and isobutyl acetate, ether solvents such as diisopropyl ether and 1,4-dioxane, cyclic polysiloxanes with a polymerization degree of 3 to 6 such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, and halogenated hydrocarbons such as trichloroethylene, perchloroethylene, trifluorotoluene, 1,3-bis(trifluoromethyl)benzene and methylpentafluorobenzene. When a thin layer of the curable organopolysiloxane composition of the present invention is applied to a thin sheet substrate such as polyolefin having low heat resistance, it is preferred to use an aromatic hydrocarbon solvent such as toluene or xylene because it has little effect on the curability of the composition.

In addition to the above-mentioned components (A) to (D) and the optional component (E), the curable organopolysiloxane composition of the present invention preferably further contains (F) a hydrosilylation reaction inhibitor in order to inhibit gelation and curing at room temperature, improve storage stability, and ensure curability when heated. Examples of the hydrosilylation reaction inhibitor include acetylene compounds, enyne compounds, organic nitrogen compounds, organic phosphorus compounds, and oxime compounds. As specific compounds, there can be mentioned alkynols such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 2-phenyl-3-butyn-2-ol, and 1-ethyn-1-cyclohexanol (ETCH); 3-methyl-3-trimethylsilanyloxy-1-butynyl, 3-methyl-3-trimethylsilanyloxy-1-pentynyl, 3,5-dimethyl-3-trimethylsilanyloxy- Enyne compounds such as 1-hexyne, 3-methyl-3-pentene-1-yne and 3,5-dimethyl-3-hexene-1-yne; alkenylsiloxanes such as 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynyloxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane.

Regarding the amount of (F) the hydrosilylation reaction inhibitor added to the curable organopolysiloxane composition, the amount of component (F) is generally in the range of 0.001 to 5 parts by mass per 100 parts by mass of component (A). However, the preferred amount of component (F) can be easily determined based on the type of component (F), the properties and amount of the hydrosilylation reaction catalyst used, the content of C2 to C12 alkenyl groups in components (A) and (B), the amount of hydrogen atoms bonded to silicon atoms in component (C), and the desired service life of the curable composition and the operating environment.

The curable organopolysiloxane composition of the present invention comprises the above-mentioned components (A) to (D), optional component (E) and component (F), and undergoes an addition reaction at room temperature or 50 to 200° C. in the presence of (D) a hydrosilylation reaction catalyst, thereby being able to form a hardened film with excellent release properties.

Furthermore, in order to ensure that the obtained hardened film has excellent physical properties and peeling properties, it is preferred to harden the curable organopolysiloxane composition of the present invention by energy rays (also called chemical action rays), such as ultraviolet rays or electron beams, especially ultraviolet irradiation. In this case, ultraviolet curing can be performed only by ultraviolet curing, or ultraviolet curing and heat curing can be performed simultaneously. The curing time of the curable composition can be appropriately adjusted according to the curing conditions used. In order to make the curable organopolysiloxane composition of the present invention have good ultraviolet curability, it is preferred to further mix (G) a photopolymerization initiator in the composition. The following is an explanation of component (G).

(G) The photopolymerization initiator is a component that imparts UV curability to the curable organopolysiloxane composition of the present invention, and has the following advantages: by combining the heat curing of the addition reaction with the UV curing, it is possible to reduce the heat damage to the plastic film substrate with low heat resistance, and improve the adhesion of the cured product of the present invention to the plastic film. In addition, it also has the advantage of being able to prevent the organic silicon component from migrating from the surface of the hardened film formed by the curing composition of the present invention to the thin film, causing the thin film to be contaminated by the organic silicon component (this is called the transfer of organic silicon), and further reduce the transfer of organic silicon. The component (G) is a well-known compound that generates free radicals when exposed to ultraviolet light, and can be appropriately selected from organic peroxides, carbonyl compounds, organic sulfur compounds, and azo compounds. Specific compounds include acetophenone, propiophenone, benzophenone, crotonol, fluorene, benzaldehyde, anthraquinone, triphenylamine, 4-methylacetophenone, 3-amylacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylacetophenone, p-diethylbenzene, 3-methoxybenzophenone, 4-methylbenzophenone, 4-chlorobenzophenone, 4,4-dimethoxybenzophenone, 4-chloro-4-benzylbenzophenone, 3 -chlorothiazonone, 3,9-dichlorothiazonone, 3-chloro-8-nonyloxyanthrone, benzoin, benzoin methyl ether, benzoin butyl ether, bis(4-dimethylaminophenyl)ketone, benzylmethoxy ketal, 2-chlorothiazonone, diethylacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl〔4-(methylthio)phenyl〕2-morpholino-1-propanone, 2,2-dimethoxy-2-phenylacetophenone and diethoxyacetophenone. When the composition of the present invention is cured by ultraviolet light, component (G) is preferably benzophenone, 4-methoxyacetophenone, 4-methylbenzophenone, diethoxyacetophenone and 1-hydroxycyclohexylphenylketone. Particularly preferred component (G) include diethoxyacetophenone and 1-hydroxycyclohexylphenyl ketone.

The above-mentioned (G) photopolymerization initiator may be used alone or in combination of two or more. The mixing amount thereof is not particularly limited, but is in the range of 0.01 to 10 parts by mass, preferably 0.01 to 2.5 parts by mass, relative to 100 parts by mass of the (A) component. If the mixing amount of the (G) component is within the above range, the peelable hardened film obtained by hardening the composition of the present invention can improve the transferability of the organic silicon and has excellent physical properties such as strength.

The curable organopolysiloxane composition of the present invention is suitable for use as a solution-type curable organopolysiloxane composition containing (E) an organic solvent. In order to obtain good coating properties of the composition on a flaky substrate, the overall viscosity of the curable organopolysiloxane composition of the present invention is preferably in the range of 100 to 100,000 mPa･s at 25°C, and the overall viscosity of the composition is more preferably 100 to 50,000 mPa･s.

[Other optional ingredients] In addition to the above-mentioned ingredients, other optional ingredients may be added to the curable organopolysiloxane composition of the present invention. Examples of other optional ingredients include adhesion enhancers composed of alkoxysilane compounds such as 3-glycidyloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane; antioxidants such as phenol-based, quinone-based, amine-based, phosphorus-based, phosphorous acid-based, sulfur-based, and thioether-based; light stabilizers such as triazole-based and benzophenone-based; phosphate-based, halogen-based, phosphorus-based, and and antimony-based flame retardants; one or more surfactants selected from cationic surfactants, anionic surfactants and non-ionic surfactants; well-known additives such as antistatic agents, heat-resistant agents, dyes and pigments, which can be added to the curable organopolysiloxane composition of the present invention using one component selected from these or a combination of two or more components.

[Manufacturing method of composition] When the composition of the present invention uses the above-mentioned components (A) to (D), optional component (E), component (F), component (G) and other optional components, it can be manufactured by further uniformly mixing these components. The order of adding the components is not particularly limited. When the composition obtained after mixing is not used immediately, it is preferred to mix components (A), component (B) and component (C), store them separately from component (D), and mix the two before use. In addition, in the composition composed of components (A) to (D), optional component (E) and other components, it is preferred to adjust the type and mixing amount of (F) hydrosilylation reaction inhibitor so that it does not crosslink at room temperature, but crosslinks and hardens when heated.

[Use of the composition: peeling coating agent and peeling sheet] The curable organopolysiloxane composition of the present invention can be used as a peeling coating agent. The composition is uniformly coated on a flaky substrate, and heated, irradiated with energy rays (such as ultraviolet rays, electron beams, etc.) or a combination of these measures under sufficient conditions for the hydrosilylation reaction and crosslinking of components (A) to (C). A peeling sheet having a peeling layer composed of a cured organosilicone film (i.e., a cured organopolysiloxane film) on the surface of the flaky substrate can be obtained. The peelable sheet of the present invention has the following characteristics: the coating property of the adhesive substance on the hardened organic silicon film is good, the adhesive substance after drying is easily peeled off from the substrate, and the viscosity and adhesive force of the adhesive substance are not reduced. That is, the peelable sheet of the present invention obtained as above is suitable for use as a peelable sheet for adhesive substances. In addition, the hardened layer formed by hardening the hardening composition of the present invention has the following advantages: due to its excellent softness, it has good compliance with the substrate, and rarely involves bubbles when it is adhered to a non-planar object. Therefore, it is extremely suitable for applications such as optical displays and protective films on glass surfaces, which require both the peeling properties of the hardened layer and the adhesion properties of the hardened layer to the object to be protected.

There is no particular limitation on the sheet-like substrate for coating the curable organopolysiloxane composition of the present invention, and any material can be appropriately selected from the materials known so far. Examples of such a substrate include films made of polyesters such as polyethylene terephthalate and polyethylene naphthalate; polyolefins such as polypropylene and polymethylpentene; and plastics such as polycarbonate and polyvinyl acetate. The film may be a single layer or may be composed of two or more layers of the same or different plastics. The sheet-like substrate used in the present invention is preferably a plastic film or a polyester film, and a polyethylene terephthalate film is particularly preferred. Among them, it is preferred to use a biaxially stretched polyethylene terephthalate film as the sheet-like substrate. Polyethylene terephthalate film is not easy to generate dust during processing and use. Therefore, it can effectively prevent dust from causing poor coating of sticky substances on the sheet-like substrate. In addition, anti-static treatment is applied to polyethylene terephthalate film and used as a sheet-like substrate, which can also effectively prevent the occurrence of problems such as poor coating of sticky substances on the sheet-like substrate.

In addition, in order to improve the adhesion between the curable organopolysiloxane of the present invention coated and cured on the surface of the flaky substrate and the surface of the flaky substrate, the flaky substrate may be subjected to surface treatment such as oxidation or embossing, or plasma treatment on one or both sides as required. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment; examples of the embossing method include sandblasting and thermal spraying. The surface treatment methods can be selected according to the type of flaky substrate, but the best method is the corona discharge treatment method, which can ensure that the desired effect is obtained by treating the surface of the flaky substrate and is easy to operate.

The thickness of the sheet-like substrate is generally 10 to 300 µm, preferably 15 to 200 µm, and particularly preferably 20 to 125 µm.

The curable organopolysiloxane composition of the present invention may be applied to a sheet-like substrate by any known method, such as gravure coating, rod coating, spray coating, spin coating, doctor blade coating, roll coating, and slit coating.

When the curable organopolysiloxane composition of the present invention is coated on a flaky substrate and cured, the thickness of the cured organopolysiloxane composition is not particularly limited, but is preferably 0.01 to 3 µm, more preferably 0.03 to 1 µm. When the thickness of the cured organopolysiloxane composition on the flaky substrate is less than 0.01 µm, the layer may not fully function as a peeling agent layer when it is used as a peeling sheet for adhesive substances. On the other hand, when the thickness of the cured organopolysiloxane composition on the flaky substrate exceeds 3 µm, agglomeration may occur when the obtained peeling sheet is rolled into a tube. Furthermore, in addition to the above-mentioned antistatic layer, other layers may be arbitrarily selected and provided on the surface of the flaky substrate opposite to the cured organic polysiloxane composition layer, or between the flaky substrate surface and the organic polysiloxane composition layer.

[Laminar body] The curable organopolysiloxane composition of the present invention can be used as a peelable layer-forming organopolysiloxane composition (= peelable coating agent) used to form a peelable layer when manufacturing a peelable laminate represented by an adhesive sheet. The laminate involved in the present invention is characterized in that it is a laminate having a structure in which an adhesive layer and at least one peelable layer are arranged facing each other, and the peelable layer is a peelable layer composed of a cured product formed by curing the peelable coating involved in the present invention. Here, the peeling layer is preferably formed on a thin sheet-like substrate. The composition involved in the present invention is suitable for use as a peeling sheet for an adhesive having a thin sheet-like substrate and a hardened layer obtained by coating and hardening the curable organopolysiloxane composition of the present invention thereon, and the peeling sheet for an adhesive is suitable for forming an adhesive laminate including an adhesive and the peeling sheet for an adhesive.

The viscous material laminate can be prepared by the following method: a method including a process of coating the viscous material on the surface of the hardened organopolysiloxane composition on the peeling sheet for viscous material of the present invention, and drying/hardening the viscous material. More specifically, the viscous material is coated on the surface of the hardened organopolysiloxane composition layer formed on the peeling sheet for viscous material of the present invention using any coating method, such as slot die coating method or doctor blade method, and then dried/hardened to form the viscous material laminate. Afterwards, a sheet-like substrate coated with or not coated with the curable organopolysiloxane composition of the present invention may be optionally adhered to the adhesive layer. The peeling sheet for adhesive of the present invention has excellent peeling property from such adhesive layer, and the adhesive will not break or other defects, and it can be peeled from the adhesive layer with a relatively small peeling force. In addition, as described above, the curable organopolysiloxane composition of the present invention has the characteristic of not reducing the viscosity and adhesive force of the adhesive layer composed of the adhesive.

In addition, as a form of other adhesive layered bodies, it can also be produced by the following method: including a process of drying/hardening the adhesive on a sheet-like substrate that is not coated with the curable organopolysiloxane composition of the present invention, and then sticking the adhesive peeling sheet of the present invention to the adhesive. In this form, the adhesive peeling sheet of the present invention has the following characteristics: it has excellent peeling properties from such adhesive layered bodies, the adhesive will not have defects such as cracks, it can be peeled from the adhesive layer with a relatively small peeling force, and the viscosity and adhesive force of the adhesive layer will not be reduced.

As described above, the curable organopolysiloxane composition of the present invention is suitable for use as a peeling sheet for adhesive substances, but its use is not limited thereto and can be used for surface treatment of various films and sheets. The peeling sheet having a curing layer composed of the composition of the present invention can be used in particular as a surface protection film for protecting the surface of optical parts such as liquid crystal panels, plasma displays, polarizing plates and phase difference plates, or electrical and electronic parts such as printed wiring boards, ICs, transistors, and capacitors. In this case, it is preferred to add an antistatic agent to the composition of the present invention.

The antistatic agent is not particularly limited, and a well-known ionic or non-ionic antistatic agent can be used, for example, a method of adding a polysilicone oil having a hydrophilic group to the main component (Japanese Patent Laid-Open No. 52-103499), a method of adding a sulfonic acid salt (Japanese Patent Laid-Open No. 3-59096), a method of adding a fluorinated polysilicone oil (Japanese Patent Laid-Open No. 1-83085, Japanese Patent Laid-Open No. 1-83086), a method of adding a fluorinated polysilicone oil (Japanese Patent Laid-Open No. 1-83087, Japanese Patent Laid-Open No. 1-83088) to the main component. The present invention discloses a method of adding a polysilicone oil containing a surfactant (Japanese Patent Publication No. 1-83086, Japanese Patent Publication No. 1-121390), a method of adding a polysilicone oil containing a surfactant (Japanese Patent Publication No. 1-294099), a method of adding a conductive powder (Japanese Patent Publication No. 2-69763, Japanese Patent Publication No. 3-292180, Japanese Patent Publication No. 4-86765), etc. In view of the compatibility with the curable organopolysiloxane composition of the present invention, an antistatic agent using a lithium salt or a polyether-modified polysiloxane is particularly preferred. The ionic antistatic agent or polyether-modified polysiloxane may be, for example, the materials disclosed in Japanese Patent Publication No. 2009-30028, Japanese Patent Publication No. 2012-157978, and Japanese Patent Publication No. 2011-178828, without any particular limitation. Moreover, from the perspective of antistatic, it can be used not only as an additive to the antistatic agent, but also as an antistatic agent of a surfactant system, an organic silicon system, an organic boron system, a conductive polymer system, a metal oxide system, a vapor-deposited metal system, etc. Example

The following shows the embodiments and comparative examples of the present invention together to more specifically illustrate the present invention, but the present invention is not limited to the following embodiments. In the following examples, "parts" indicating the amount refer to parts by mass, and the vinyl (CH ₂ =CH-) part refers to the vinyl (CH ₂ =CH-) part in the alkenyl group bonded to the silicon atom. The content of the vinyl part in the entire molecular weight is expressed in mass %, and when the alkenyl group is a vinyl group, it is simply referred to as "vinyl content". The viscosity and plasticity are values measured at 25°C. The method for measuring plasticity is as described above, and a digital display B-type rotational viscometer (Vismetron VDA2 manufactured by Shibaura Systems Co., Ltd.) was used to measure the viscosity.

[Method for preparing release sheet] Using a Mayer bar, a curable organopolysiloxane composition was applied to the surface of a biaxially stretched polyester film (Mitsubishi Resin, thickness 38 µm) in an amount of 0.15 g/m2 of solid content after solvent removal. After application, the substrate coated with the composition was heated at 120°C for 30 seconds in a hot air circulation oven to form a hardened layer of organopolysiloxane on the surface of the polyester film substrate, and the peeling sheet was prepared by storing the substrate in an air temperature of 25°C and a humidity of 60% for 72 hours.

[Evaluation of coating properties] The uniformity of the coating surface of the above-mentioned peeling sheet was visually observed, and those with uniform appearance were judged as passing, and those with uneven appearance were judged as failing.

[Measurement of the peeling resistance of sticky substances] TESA7475 adhesive tape manufactured by TESA was pasted onto the obtained peeling sheet, a load of 20 g/ ^cm2 was applied, and the sheet was placed in air at a temperature of 25°C and a humidity of 60% for 24 hours. Afterwards, the adhesive tape was stretched at an angle of 180 degrees and a peeling speed of 0.3m/min using a tensile tester [Tensile force universal tester manufactured by A&D Co., Ltd.], and the force required for peeling (mN/50 mm) was measured. If the peeling force measured by this method is less than 55mN/5 cm, the peeling characteristics are judged to be good; if it exceeds 55mN/50 mm, the peeling characteristics are judged to be poor.

[Measurement of residual adhesion] Adhesive tape No. 31B manufactured by Nitto Denko Corporation was pasted on the peeling sheet, a load of 20 g/ ^cm2 was applied, and the sheet was placed at a temperature of 70°C for 20 hours. Then, the adhesive tape was torn off, and the torn adhesive tape was pasted on a stainless steel plate, a load of 20 g/ ^cm2 was applied, and the sheet was placed in air at a temperature of 25°C and a humidity of 60% for 30 minutes. Then, the adhesive tape was stretched at an angle of 180 degrees and a peeling speed of 0.3 m/min using a tensile tester [tensile force universal tester manufactured by A&D Co., Ltd.], and the force required for peeling (gf1) was measured. In addition, as a blank test, the above-mentioned tape was attached to a Teflon (registered trademark) sheet in the same manner as above, and the force (gf2) required to peel off the adhesive tape was measured according to the above operation. The residual adhesion rate (%) was calculated from these values according to the following formula. Residual adhesion rate (%) = (gf1/gf2) × 100 A residual adhesion rate of 95% or more was considered acceptable, and a residual adhesion rate of less than 95% was considered unacceptable.

[Example 1] Composition 1 66.7 parts of (A) (a-1) polydimethylsiloxane having methyl groups at both ends of the molecular chain and hexenyl groups in the side chain (plasticity 1.15, content of vinyl (CH ₂ =CH-) part in the hexenyl group 0.80 mass%), 33.3 parts of (B) (b-1) dimethylsiloxane having methyl groups at both ends of the molecular chain and hexenyl groups in the side chain (viscosity 350 mPa･s, vinyl content 1.20 mass%), and 25 mPa･s, dimethylmethyl hydropolysiloxane having both ends of the molecular chain capped by trimethylsiloxy groups, a SiH/Vi ratio of 1.2 in the entire composition, (E) 100.0 parts of toluene and (F) 1.5 parts of 3-methyl-1-butyn-3-ol were uniformly mixed to obtain a curable organopolysiloxane composition containing a solvent (composition 1-1). Furthermore, the obtained organopolysiloxane composition was diluted with (E) a mixed solution of toluene/hexane = 50/50 mass % to make the solid concentration 5.0 mass %, and (D) chloroplatinate-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex was added and mixed in an amount of 200 ppm of platinum metal relative to the total amount of components (A) to (C). The obtained material was used to obtain a peeling sheet according to the above method. The peeling sheet obtained in this way was observed for appearance, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Example 2] Composition 2 Except for changing the amount of component (A) used in Example 1 to 50.0 parts and the amount of component (B) used to 50.0 parts, the other operations were the same as in Example 1 to obtain Composition 2. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Example 3] Composition 3 Except for changing the amount of component (A) used in Example 1 to 33.3 parts and the amount of component (B) used to 66.7 parts, the other operations were the same as in Example 1 to obtain Composition 3. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 1] Comparative composition 1 Except that the component (B) of Example 1 is not used, the amount of component (A) is changed to 100.0 parts, the amount of component (E) is changed to 333.3 parts, and the amount of component (F) is changed to 0.9 parts, the other operations are the same as those of Example 1 to obtain comparative composition 1. The appearance of the peeling sheet obtained in this way was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 2] Comparative composition 2 Except that the component (A) of Example 1 is not used and the amount of the component (B) used is changed to 100.0 parts, the other operations are the same as those of Example 1 to obtain composition 2. The appearance of the peeling sheet obtained in this way was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 3] Comparative composition 3 Except for using 66.7 parts of polydimethylsiloxane (plasticity 1.50, vinyl content 0.75 mass%) with vinyl groups at both ends of the molecular chain (a-2) as the (A) component of composition 1 of Example 1, the other operations were the same as those of Example 1 to obtain comparative composition 3. The appearance of the peeling sheet obtained in this way was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 4] Comparative composition 4 Except that the amount of component (A) in comparative composition 3 of comparative example 3 was changed to 50.0 parts and the amount of component (B) was changed to 50.0 parts, the other operations were the same as those of Example 1 to obtain comparative composition 4. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 5] Comparative composition 5 Except that the amount of component (A) in comparative composition 3 of comparative example 3 was changed to 33.3 parts and the amount of component (B) was changed to 66.7 parts, the other operations were the same as those of Example 1 to obtain comparative composition 5. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 6] Comparative composition 6 The same operation as in Example 1 was performed except that 33.3 parts of polydimethylsiloxane (viscosity 400 mPa･s, content of vinyl (CH ₂ =CH-) part in the hexenyl group 0.97 mass %) with hexenyl groups at both ends of the molecular chain (b-2) was used as the (B) component of the composition 1 of Example 1, thereby obtaining comparative composition 6. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 7] Comparative composition 7 Except for changing the amount of component (A) used in comparative composition 6 of comparative example 6 to 50.0 parts and the amount of component (B) used to 50.0 parts, the other operations were the same as those of Example 1 to obtain comparative composition 7. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 8] Comparative composition 8 Except that the amount of component (A) in comparative composition 6 of comparative example 6 was changed to 33.3 parts and the amount of component (B) was changed to 66.7 parts, the other operations were the same as those of Example 1 to obtain comparative composition 8. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 9] Comparative composition 9 Except that 66.7 parts of polydimethylsiloxane (plasticity 1.50, vinyl content 0.75 mass%) with vinyl groups at both ends of the molecular chain (a-2) was used as the (A) component of the comparative composition 1 of Comparative Example 1, the other operations were the same as those of Comparative Example 1 to obtain Comparative composition 9. The appearance of the peeling sheet obtained in this way was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

[Comparative Example 10] Comparative composition 10 Except that polydimethylsiloxane (plasticity 1.50, vinyl content 0.85 mass%) with methyl groups at both ends of the molecular chain (a-3) and vinyl groups in the side chain was used as the (A) component of the comparative composition 1 of comparative example 1, the other operations were the same as those of comparative example 1 to obtain comparative composition 9. The appearance of the peeling sheet thus obtained was observed, and the peeling force and residual adhesion rate were evaluated. The results are shown in Table 1.

When the chemical formula (1) represents the component (A) and the chemical formula (3) represents the component (B), Table 1 also shows the functional groups at the terminals and side chains of the components (a-1) to (a-3) and the components (b-1) and (b-2). Chemical formula 6 Chemical formula 7

Table 1 (A) Ingredients (B) Ingredients Appearance Peeling resistance (mN/5 cm) Residual adhesion rate (%) (a-1) (a-2) (a-3) (b-1) (b-2) Functional Group R ¹ or R ¹¹ (terminal/side chain) * Non-reactive methyl methyl methyl methyl methyl R ² or R ¹² (terminal part) methyl Vinyl methyl methyl Hexenyl R ³ or R ¹³ (side chain part) Hexenyl Vinyl Vinyl Hexenyl Hexenyl Composition 1 66.7 33.3 good 53 98 Composition 2 50.0 50.0 good 50 98 Composition 3 33.3 66.7 good 47 98 Comparison composition 1 100.0 good 73 100 Comparison composition 2 100.0 bad 50 96 Comparison composition 3 66.7 33.3 good 70 98 Comparison composition 4 50.0 50.0 good 68 98 Comparison composition 5 33.3 66.7 good 68 98 Comparison composition 6 66.7 33.3 good 85 99 Comparison composition 7 50.0 50.0 good 88 98 Comparison composition 8 33.3 66.7 good 87 98 Comparison composition 9 100.0 good 90 99 Comparison composition 10 100.0 good 120 99

According to the results shown in Table 1, it is clear that when the composition (Examples 1 to 3) in which both component (A) and component (B) have alkenyl groups only in the side chains is hardened, the peeling sheet obtained has excellent appearance, low peeling resistance value for sticky substances, and good residual adhesion rate. On the other hand, in the comparative experiment, when the components (A) and (B) of the present invention are not used together, or the raw material uses an organic polysiloxane having alkenyl groups in other parts besides the side chains, the peeling layer obtained by the comparative compositions 1, 3 to 10 (Comparative Examples 1 and 3 to 10) has high peeling resistance for sticky substances and cannot achieve good peeling characteristics. Furthermore, in the comparative composition 2 (Comparative Example 2) using only the component (B), it was difficult to uniformly apply the composition on the base film, and the peeled sheet had a poor appearance and could not achieve practical coating properties.

without

without

Claims (9)

A curable organopolysiloxane composition comprising: (A) a liquid having a viscosity of 1,000,000 mPa.s or more at 25°C or a rubbery state having plasticity at 25°C, having only an alkenyl group having 4 to 12 carbon atoms on the molecular side chain, wherein the content of the vinyl ( _CH2 =CH-) part in the alkenyl group is 0.5 to 3.0 mass %, and the molecular chain terminal is capped by a trialkylsilyl group; (B) a straight chain organopolysiloxane having a viscosity of 1,000 mPa.s or more at 25°C. s or less, only the side chain of the molecule has an alkenyl group having 4 to 12 carbon atoms, the content of the vinyl ( _CH2 =CH-) part in the alkenyl group is 0.5 to 3.0 mass %, and the molecular chain end is terminated by a trialkylsilyl group; (C) an organic hydropolysiloxane having two or more silicon-bonded hydrogen atoms (Si-H) in one molecule; and (D) a hydrosilylation reaction catalyst; and the mass ratio of the component (A) to the component (B) {(A)/(B)} is in the range of 95/5 to 5/95. The curable organopolysiloxane composition as described in claim 1, wherein the mass ratio {(A)/(B)} of component (A) to component (B) is in the range of 90/10 to 10/90. The curable organopolysiloxane composition as described in claim 1 or 2 further contains (E) an organic solvent. The curable organopolysiloxane composition as described in claim 1 or 2 further contains (F) a hydrosilylation reaction inhibitor. The curable organopolysiloxane composition as described in claim 1 or 2 further contains (G) a photopolymerization initiator. The curable organopolysiloxane composition as described in claim 1 or 2, wherein the mass ratio of component (A) to component (B) {(A)/(B)} is in the range of 70/30 to 30/70, and the molar ratio of SiH groups in component (C) is 0.5 to 5 relative to the total molar number of alkenyl groups in components (A) and (B). A stripping coating agent, which is composed of the curable organic polysiloxane composition described in any one of claims 1 to 6. A sheet-like article having a hardened layer formed by hardening the hardening organic polysiloxane composition described in any one of claims 1 to 6 and a sheet-like substrate. A laminate having a structure in which an adhesive layer and at least one peeling layer are arranged facing each other, wherein the peeling layer is a peeling layer composed of a hardened material formed by hardening the peeling coating agent described in claim 7.