TWI854966B - Solvent-based curable organopolysiloxane composition, release sheet, and manufacturing process thereof - Google Patents

Abstract

[Topic] The present invention provides a solvent-curable organopolysilicone composition which can form a release coating having excellent workability including transportability in a state where the content of organic solvent is relatively low, excellent wettability/coating properties on sheet substrates such as plastic films, good peeling force and excellent stability over time when a large amount of organic solvent is used for dilution in the production process of the release sheet, a release sheet using the same and a method for manufacturing the same. [Solution] A solvent-curable organopolysiloxane composition comprises (A) an organopolysiloxane having at least 3 alkenyl groups with 4 to 12 carbon atoms in the molecule, wherein the content of the vinyl ( _CH2 =CH-) part in the alkenyl group is 0.1 to 5.0 mass %, and the viscosity is within the range of 5,000 to 100,000 mPa･s, (B) an organohydropolysiloxane, (C) a silanization reaction catalyst, (D) a silanization reaction inhibitor, and (E) an organic solvent.

Description

Solvent-type curable organic polysilicone composition, peelable sheet and manufacturing method thereof

The present invention relates to a solvent-curable organopolysilicone composition which can form a release coating having excellent workability including transportability in a state where the content of organic solvent is relatively small, excellent wettability/applicability to sheet substrates such as plastic films, good peeling force and excellent stability over time when a large amount of organic solvent is used for dilution in the production process of the release sheet, a release sheet using the same and a method for manufacturing the same.

It is well known that a method of obtaining a material having releasability to an adhesive substance is provided by coating a polysilicone composition for forming a releasable hardening film on the surface of a film or sheet substrate such as paper, laminated paper, plastic film, or metal foil, and heating the surface to form a hardening film. As the polysilicone composition for forming a releasable hardening film used in the method, it is well known that a silicone composition is formed by curing the composition by an addition reaction in the presence of a platinum catalyst using an alkenyl-containing organopolysiloxane and an organohydropolysiloxane as the main components.

Such silicone-based stripping agents can be generally classified into solvent-free type without organic solvent, solvent type which is applied to the substrate after dilution with organic solvent, and water-based emulsion type according to the solvent. In recent years, the demand for functional films with stripping coatings formed on plastic films, such as protective films, stripping films for dielectric ceramic layer molding materials, separation films for adhesives, and separation films for functional films, has been increasing. Considering the viewpoint of coating silicone-based stripping agents on plastic films, solvent-based silicone-based stripping agents are strongly required. For example, Patent Documents 1 and 2 propose a solvent-free polysilicone-based stripping agent using an organic polysilicone containing an olefin group with a low polymerization degree and low viscosity. However, when such stripping agents are thinly applied to a plastic film, the coating layer tends to shrink, and sometimes a uniform coating surface cannot be obtained. In addition, as for water-based emulsion-type stripping agents, it is difficult to apply them to water-repellent plastic films.

On the other hand, the applicant of this application proposed, for example, in patent documents 3 to 5, a solvent-type silane-hydrogenated reactive polysiloxane stripping agent having a higher alkenyl group such as hexenyl and containing an organic polysiloxane with a high degree of polymerization, and a functional film using the same. The solvent-type polysiloxane stripping agent can be directly applied to a plastic film and can sufficiently improve wettability/coating properties, and is therefore particularly useful in forming a functional film having a stripping coating formed on a plastic film. Furthermore, a stripping agent containing an organic polysilicone having a higher alkenyl group represented by a hexenyl group as a main component can form a hardened film that has a fast curing speed and excellent stripping performance for adhesive substances when heated at a relatively low temperature below 100°C, so that the plastic film is not easily damaged by the heating generated by the formation of the hardened film. [Known technical literature] [Patent literature]

Patent document 1: Japanese Patent Publication No. 2005-343974 (Patent Registration No. 4434841) Patent document 2: Japanese Patent Publication No. 2011-026582 (Patent Registration No. 5683848) Patent document 3: Japanese Patent Publication No. 09-125004 (Patent Registration No. 4367670) Patent document 4: Japanese Patent Publication No. 2009-114285 (Patent Registration No. 5492377) Patent document 5: Japanese Patent Publication No. 2017-503903

[Identify the problem you want to solve]

However, the inventors of the present invention have discovered a new problem regarding a polysilicone-based stripping agent using a highly polymerized organic polysilicone containing a higher alkenyl group such as a hexenyl group.

That is, these silicone-based stripping agents have excellent wettability/applicability on plastic films, etc. In recent years, in view of reducing environmental pollution, the use of organic solvents has been widely sought in the industrial field to reduce or limit the amount of organic solvents used. However, when a solvent-type stripping agent containing organic silicone with a high degree of polymerization is applied to a sheet substrate such as a plastic film, a large amount of organic solvent must be used. In addition, in the industrial production process, if the amount of organic solvent used is reduced, the viscosity of the silicone-based stripping agent will be too large, which will result in a significant deterioration in the supply and operability of the production line. In contrast, as the main agent of the silicone-based stripping agent, for example, as disclosed in the aforementioned patent document 2, a low degree of polymerization and low viscosity hexenyl-containing organic polysilicone can also be selected. However, regardless of whether it is a solvent-free type or a solvent-diluted type, the low degree of polymerization hexenyl-containing organic polysilicone still has insufficient wettability/applicability for plastic films.

The present invention is to solve the above-mentioned problem. Its purpose is to provide a solvent-curable organic polysilicone composition that can reduce the amount of organic solvent used in the entire manufacturing process of a release sheet without causing any problems in industrial production, and can be evenly coated on a sheet substrate such as a plastic film to form a release layer with good release properties, a release sheet using the same, and a method for manufacturing the same. [Technical means for solving the problem]

After intensive research, the inventors of the present invention finally found that the above-mentioned problems can be solved by using a solvent-curable organopolysiloxane composition comprising (A) at least three alkenyl groups with 4 to 12 carbon atoms in the molecule, wherein the content of the vinyl (CH ₂ =CH-) part in the alkenyl group is 0.1 to 5.0 mass % and the viscosity at 25°C is within the range of 5,000 to 100,000 mPa･s, (B) an organohydropolysiloxane having two or more silicon-bonded hydrogen atoms (Si-H) in one molecule, (C) a silanization reaction catalyst, (D) a silanization reaction inhibitor, and (E) an organic solvent, thereby completing the present invention.

In the above solvent-curable organopolysiloxane composition, component (A) has excellent wettability/applicability on plastic films and excellent peeling properties of the release layer by selecting the type of curing reactive group and the specific viscosity range. Moreover, the organic solvent content is small, and even if the solvent-curable organopolysiloxane composition is designed to have a higher solid concentration, it has excellent workability and transportability, and can be used after being diluted with a desired organic solvent on the production line of the release sheet. Therefore, depending on the amount of organic solvent, it can be used as a raw material for a solvent-diluted stripping agent composition or as a stripping agent composition itself. In particular, the raw material for a solvent-diluted stripping agent composition can be easily transported to a production line for operation in the form of a product with a relatively low organic solvent content, and on a production line equipped with a solvent recovery process, a stripping sheet can be efficiently manufactured by recycling only a small amount of organic solvent.

That is, the present invention is "[1] a solvent-curable organopolysiloxane composition comprising the following components: (A) one or more organopolysiloxanes having at least three alkenyl groups with 4 to 12 carbon atoms in the molecule, wherein the content of the vinyl ( _CH2 =CH-) moiety in the alkenyl groups is 0.1 to 5.0 mass %, and the viscosity at 25°C is within the range of 5,000 to 100,000 mPa･s; (B) an organohydropolysiloxane having two or more silicon-atom-bonded hydrogen atoms (Si-H) in one molecule; (C) a silanization reaction catalyst; (D) a silanization reaction inhibitor; and (E) an organic solvent. [2] The solvent-curable organopolysiloxane composition as described in [1], wherein component (A) is one or more organopolysiloxanes having a viscosity at 25°C in the range of 10,000 to 50,000 mPa･s, and the content of (E) the organic solvent is in the range of 1 to 99% by mass of the entire composition. [3] The solvent-curable organopolysiloxane composition as described in [1] or [2], wherein component (A) is an organopolysiloxane containing a hexenyl group as the alkenyl group having 4 to 12 carbon atoms, and the content of the organopolysiloxane having an alkenyl group having less than 4 carbon atoms in the composition is not more than 5.0% by mass of component (A). [4] A solvent-curable organopolysiloxane composition as described in any one of [1] to [3], wherein the amount of hydrogen atoms bonded to silicon atoms in component (B) is in the range of 1.0 to 10.0 mol per 1 mol of carbon-carbon double bonds in component (A). [5] A solvent-curable organopolysiloxane composition as described in any one of [1] to [4], which is a stripping agent composition or a solvent-dilutable stripping agent composition raw material used in the formation of a stripping coating. [6] A solvent-curable organopolysiloxane composition as described in any one of [1] to [4], wherein the viscosity of the composition as a whole is 20 to 50,000 at 25°C. mPa･s, the content of the (E) organic solvent is in the range of 50 to 97.5 mass % of the whole composition, and it is a stripping agent composition used in the formation of a stripping coating. [7] A solvent-curable organopolysiloxane composition as described in any one of [1] to [4], wherein the content of the (E) organic solvent is in the range of 1 to 50 mass % of the whole composition, and it is a solvent-dilutable stripping agent composition raw material used in the formation of a stripping coating, wherein the same or different (E) organic solvent may be added. ｣.

Similarly, the present invention is [8] A releasable sheet having a releasable coating formed by curing the solvent-curable organic polysilicone composition described in any one of [1] to [7] on at least one surface of a sheet-like substrate. [9] A releasable sheet as described in [8], wherein the sheet-like substrate is a plastic film. [10] A releasable sheet as described in [8] or [9], which is used for one or more purposes selected from a protective film, a releasable film for a dielectric ceramic layer molding material, a separator film for an adhesive, and a separator film for a functional film.

In addition, the present invention is also [11] a method for producing a release sheet, which is the method for producing a release sheet as described in any one of [8] to [10], comprising the following process: process (I): in a material containing: (A) one or more organic polysilicones having at least 3 alkenyl groups with 4 to 12 carbon atoms in the molecule, wherein the content of the vinyl ( _CH2 =CH-) part in the alkenyl group is 0.1 to 5.0 mass %, and the viscosity at 25°C is in the range of 5,000 to 100,000 mPa･s; (B) an organic hydropolysilicon having two or more silicon-atom-bonded hydrogen atoms (Si-H) in one molecule; (C) a silanization reaction catalyst; (D) a silanization reaction inhibitor; and (E) A process for preparing a coating bath of a stripping agent composition by adding the same or different organic solvent (E) to a solvent-curable organopolysiloxane composition formed by an organic solvent, so that the overall viscosity of the composition at 25°C is 100~50,000 mPa･s; process (II): a process for coating the stripping agent composition prepared in process (I) on a substrate; and process (III): a process for curing the stripping agent composition applied in process (II) on the substrate at 20~200°C to form a stripping coating. [12] The method for producing a stripping sheet as described in [11] further comprises the following process: Process (IV): A process for recovering the organic solvent (E) that is volatile in process (III). ｣. [Effect of the invention]

By using the solvent-curable organic polysilicone composition of the present invention, it is possible to reduce the amount of organic solvent used and reduce environmental pollution in the industrial production process from the transportation of the raw material of the stripping agent composition to the recovery/recycling of the organic solvent in the entire series of manufacturing processes of the stripping sheet without causing any problems in industrial production. Furthermore, by using the solvent-curable organopolysiloxane composition of the present invention, a peelable sheet having good wettability/applicability to plastic films and the like and good peeling properties including a light peeling force and stability over time can be provided, and even a sheet-like substrate such as a plastic film can have a uniform peeling layer. In addition, by using the solvent-curable organopolysiloxane composition of the present invention, a method for manufacturing a peelable sheet that can improve industrial production efficiency and reduce environmental pollution can be provided.

[Solvent-type curable organopolysiloxane composition] First, the solvent-type curable organopolysiloxane composition of the present invention is described. Depending on the content of the (E) organic solvent, the composition of the present invention can be used as a raw material for a solvent-diluted stripping agent composition, or can be used as a stripping agent composition itself. That is, as a stripping agent composition raw material with a low organic solvent content and excellent workability, it can be shipped or transported to a stripping sheet manufacturing site, and diluted on the production line with the (E) organic solvent that is the same as or different from the raw material, and evenly applied to a sheet substrate such as a plastic film. Since the solvent can be recovered and recycled in the production line, it can improve industrial production efficiency (including reducing transportation costs) and reduce environmental pollution compared to shipping or transporting a curable organopolysilicone composition containing a large amount of organic solvent and a small amount of solid content to the manufacturing site. The following is an explanation of the components that make up this composition.

Component (A) is one or more organopolysiloxanes having at least three alkenyl groups with 4 to 12 carbon atoms in the molecule, wherein the content of vinyl (CH ₂ =CH-) moieties in the alkenyl groups is 0.1 to 5.0% by mass, and the viscosity at 25°C is within the range of 5,000 to 100,000 mPa･s. Preferably, the organopolysiloxane contains substantially no or no alkenyl groups with less than 4 carbon atoms bonded to silicon atoms.

The alkenyl group having 4 to 12 carbon atoms bonded to the silicon atom of component (A) is preferably an alkenyl group having 4 to 8 carbon atoms, preferably contains a hexenyl group and the content of the vinyl (CH ₂ =CH-) part in the hexenyl group is in the range of 0.1 to 4.0 mass %, more preferably in the range of 0.1 to 3.0 mass %. When the number of alkenyl groups having 4 to 12 carbon atoms in the molecule is less than 3 (e.g., 2 or 1), the crosslinking density of the cured product will be reduced, and the peeling performance of the peeling coating will become insufficient, and poor adhesion to the substrate may occur. In the present invention, by using the above-mentioned organic polysiloxane containing a higher alkenyl group as component (A), its wettability/applicability on sheet substrates such as plastic films can be improved, and at the same degree of polymerization (= viscosity) of polysiloxane, compared with organic polysiloxane containing vinyl or allyl groups, the hardness of the silicone resin can be suppressed by the silanization reaction. The peeling force of the peeling coating obtained by the chemical reaction can be changed with time, and according to expectations, it can quickly cure even under low temperature heating below 100°C, and form a hardened coating with excellent peeling performance, and has the advantage of being able to suppress damage to sheet substrates made of thermoplastic resin materials such as plastic films during the curing process.

The other organic groups in component (A) are not particularly limited, and examples thereof include alkyl groups having 1 to 20 carbon atoms substituted with hydroxyl groups (silanol groups), fluorine atoms, and phenyl groups. In view of industrial production, the other organic groups are preferably methyl groups or phenyl groups. In view of improving the releasability, the other organic groups may also contain alkyl groups having 3 or more carbon atoms substituted with fluorine atoms (e.g., trifluoropropyl groups).

The characteristic of component (A) is that the viscosity at 25°C is in the range of 5,000~100,000 mPa･s, more preferably in the range of 10,000~50,000 mPa･s, and particularly preferably in the range of 10,000~30,000 mPa･s. When the viscosity of component (A) is within the above range, the coating property as a solvent-type composition and the stripping performance of the stripping coating that can be obtained will not be impaired, and even when a composition with a small content of organic solvent is prepared, the operability in the industrial process is sufficient. Here, the viscosity at 25°C refers to the viscosity of component (A) measured at 25°C using a rotational viscometer. When the viscosity of component (A) is less than the above lower limit, when the solvent-based composition containing (E) organic solvent is thinly applied to the plastic film, the coating layer may shrink (= the coating film cannot be evenly applied to the surface of the substrate, and part or all of it becomes a pattern or hole), and a uniform coating surface cannot be obtained. On the other hand, when the viscosity of component (A) exceeds the above upper limit, if the amount of (E) organic solvent used is not increased, the viscosity will be too high, so the workability is not sufficient, and the entire manufacturing process of the release sheet, which is the purpose of the present invention, may not be able to achieve the purpose of reducing the amount of organic solvent used and reducing environmental pollution in the industrial production process.

The component (A) may be selected from a linear organic polysilicon, a branched organic polysilicon, and a linear or branched organic polysilicon containing a partial ring structure. From the viewpoint of industrial efficiency, a linear organic polysilicon represented by the following chemical formula (1) is preferred.

In formula (1), R ¹¹ independently represents an unsubstituted or halogen-substituted alkyl group having 1 to 20 carbon atoms (e.g., methyl group, etc.), an aryl group having 6 to 22 carbon atoms (e.g., phenyl group, etc.), or a hydroxyl group, preferably a methyl group or a phenyl group. ^Ra is an alkenyl group having 4 to 12 carbon atoms, and is particularly preferably a hexenyl group. R is a group represented by R ¹¹ or ^Ra . m is a number greater than or equal to 0, and n is a number greater than or equal to 1. m, n, and R are numbers such that the number of alkenyl groups having 4 to 12 carbon atoms in the organopolysiloxane molecule represented by the above formula (1) is at least 3 and the viscosity at 25°C is within the range of 5,000 to 100,000 mPa･s, and the content of the vinyl (CH ₂ =CH-) moiety in the alkenyl group is preferably 0.1 to 4.0 mass %.

For example, when both R at the two ends of formula (1) are alkenyl groups (R ^a ) having 4 to 12 carbon atoms, the content of the vinyl (CH ₂ =CH-) portion in the alkenyl group is represented by the following formula: {(molecular weight of the vinyl portion of R ^a : about 27)×(m+2)}/total molecular weight×100 (mass %), and component a1) is an organic polysilicone satisfying the condition that the content of the vinyl (CH ₂ =CH-) portion in the alkenyl group having 4 to 12 carbon atoms in formula (1) is in the range of 0.10 to 4.0 mass %, more preferably in the range of 0.10 to 3.0 mass %.

In particular, component (A) is preferably an organic polysilicone represented by the following chemical formula (2) having hexenyl groups at both ends of the molecular chain and in the side chain. (In formula (2), m1 is a number greater than or equal to 0, and n1 is a positive number, and m1 is a number such that 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) is in the range of 0.5 to 3.0 mass %, and more preferably in the range of 1.0 to 2.0 mass %. In addition, m1+n1 is a number such that the viscosity of the organopolysiloxane represented by formula (2) at 25°C is in the range of 5,000 to 100,000 or more, and more preferably in the range of 10,000 to 50,000 mPa･s or more.)

Component (A) may be composed of only one of the above-mentioned organopolysiloxanes, or may be a combination of two or more organopolysiloxanes having different structures, polymerization degrees, alkenyl group contents, etc.

The composition of the present invention is cured by a curing reaction including a silane hydrogenation reaction. In order to improve the wettability/applicability to plastic films and the like and to achieve good curability at a low temperature within a heating temperature range of 70-100°C and in a short time, it is preferred that the composition substantially does not contain an alkenyl group having less than 4 carbon atoms bonded to silicon atoms, more specifically, a vinyl group or an allyl group. The reason is that when the composition containing such alkenyl groups is a solvent-type composition, a uniform coating film may not be formed and it is not suitable for low-temperature curing. Here, the term “organic polysilicone substantially free of alkenyl groups having less than 4 carbon atoms bonded to silicon atoms” means that the content of the component in the composition is 5.0 mass % or less, preferably 3.0 mass % or less, based on component (A). Preferably, the content of the component in the entire composition is 5.0 mass % or less, preferably 3.0 mass % or less, and within the range of 0 to 1.0 mass %.

Component (B) is an organohydropolysiloxane having two or more silicon-bonded hydrogen atoms (Si-H) in one molecule, and is a crosslinking agent of the present composition. It is a crosslinking agent of the above-mentioned component (A). Component (B) 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.

The content of hydrogen atoms bonded to silicon atoms is preferably 0.1 to 2.0 mass % of the total curable organopolysiloxane composition, and more preferably 0.5 to 1.8 mass %. In addition, as an organic group bonded to silicon atoms contained in component (B) other than hydrogen atoms, alkyl groups such as methyl, ethyl, propyl, butyl, and octyl can be listed, and methyl is preferred. In addition, as a molecular structure of the organohydropolysiloxane of component (B), any one of a straight chain, a branched chain, and a branched ring can be listed, or a combination of more than one of these. Furthermore, the number of hydrogen atoms bonded to silicon atoms in one molecule is an average value of all molecules.

The viscosity of component (B) at 25°C is 1~1,000 mPa･s, preferably 5~500 mPa･s. The reason is that if the viscosity of component (B) at 25°C is less than 1 mPa･s, component (B) is easily volatilized from the curable organopolysilicone composition containing it, and if it exceeds 1,000 mPa･s, the curing time of the curable organopolysilicone composition containing such component (B) will be prolonged. Such component (B) is not particularly limited, and examples thereof include dimethylsiloxane-methylhydrosiloxane copolymers having both ends capped by trimethylsiloxy groups, dimethylsiloxane-methylhydrosiloxane copolymers having both ends capped by dimethylhydrosiloxy groups, dimethylsiloxane having both ends capped by dimethylhydrosiloxy groups, methylhydropolysiloxane having both ends capped by trimethylsiloxy groups, cyclomethylhydropolysiloxane, and cyclomethylhydrosiloxane-dimethylsiloxane copolymers.

Furthermore, in order to improve the curability and adhesion of the composition of the present invention, component (B) may also contain two or more organohydropolysiloxanes having different structures.

The amount of component (B) incorporated in the curable organopolysiloxane composition of the present invention is 1.0 to 10.0 moles of hydrogen atoms bonded to silicon atoms in component (B) relative to 1 mole of carbon-carbon double bonds in component (A), preferably 1.0 to 4.0 or 1.0 to 3.0. If the molar ratio is less than the lower limit, the curability of the curable composition obtained will be reduced, and if it exceeds the upper limit, the peeling resistance of the peelable coating obtained will increase, and good peeling performance may not be obtained.

Component (C) is a silylation catalyst, which is a catalyst that promotes the addition reaction (silylation reaction) between silicon atoms bonded to alkenyl groups and silicon atoms bonded to hydrogen atoms present in the curable organopolysiloxane composition. Preferred hydrogenation catalysts are hydrogenation catalysts containing platinum metals, specifically, chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid olefin complexes, chloroplatinic acid and ketone complexes, chloroplatinic acid and vinyl siloxane complexes, platinum tetrachloride, platinum powder, solid platinum supported on a carrier of aluminum oxide or silicon dioxide, platinum black, platinum olefin complexes, platinum alkenyl siloxane complexes, platinum carbonyl complexes, and methyl methacrylate resins, polycarbonate resins, polystyrene resins, silicone resins containing these platinum catalysts. Platinum catalysts for thermoplastic organic resin powders such as silylation resin are used. Platinum siloxane complexes such as chloroplatinic acid and divinyltetramethyldisiloxane complex, chloroplatinic acid and tetramethyltetravinylcyclotetrasiloxane complex, platinum divinyltetramethyldisiloxane complex, and platinum tetramethyltetravinylcyclotetrasiloxane complex are particularly preferred. Furthermore, non-platinum metal catalysts such as iron, ruthenium, and iron/cobalt can be used as catalysts for promoting silylation reaction.

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

Component (D) is a silanization reaction inhibitor, which is a component in the curable organopolysiloxane composition of the present invention that inhibits gelation and curing at room temperature, improves storage stability, and has curability when heated to 70° C. or above. Examples of the silanization reaction inhibitor include acetylene compounds, enyne compounds, organic nitrogen compounds, organic phosphorus compounds, and oxime compounds. As specific compounds, 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-trimethylsilyl-1-butyn, 3-methyl-3-trimethylsilyl-1-pentyn, 3,5-dimethyl-3-trimethylsilyl-1-hexyn, 3-methyl-3-pentyn-3-ol, Enyne compounds such as alkene-1-yne, and 3,5-dimethyl-3-hexene-1-yne; alkenyl siloxanes such as 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynyloxy)dimethylsilane, methyl(tris(1,1-dimethyl-2-propynyloxy))silane, 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 (D) silane hydrogenation reaction inhibitor added to the curable organopolysiloxane composition, generally, the amount of (D) is in the range of 0.001 to 5 parts by mass per 100 parts by mass of (A). However, the preferred amount of (D) can be easily determined based on the type of (D), the characteristics and amount of the silane hydrogenation reaction catalyst used, the content of C ₄ to C ₁₂ alkenyl groups in (A), the amount of hydrogen atoms bonded to silicon atoms in (B), and the desired service life and operating environment of the curable composition. In addition, in order to achieve the intended service life, the above-mentioned (D) silane hydrogenation reaction inhibitor can be used alone or in combination of two or more.

Furthermore, when the (E) organic solvent used in diluting the composition is recycled, the curable organopolysiloxane composition diluted with the recycled solvent may be poorly cured due to the accidental mixing of the above-mentioned (D) silane hydrogenation reaction inhibitor. However, this problem can be solved by selecting the types of organic solvent and silane hydrogenation reaction inhibitor and the difference in boiling points, for example, as proposed by the applicant of the present application in Japanese Patent Publication No. 2010-018751.

The curable organopolysiloxane composition of the present invention is a solvent type, contains (E) an organic solvent, and has good workability and coating properties. The composition containing components (A) to (D) and other arbitrary components can be dispersed or dissolved in a well-known organic solvent for use. In addition, within the scope of not impairing the purpose of the present invention, the components (A) to (D) and other arbitrary components can also be dispersed or dissolved in a low-viscosity liquid organopolysiloxane (for example, a chain or cyclic organopolysiloxane with a viscosity as low as 0.5 to 10 mPas at 25°C) other than an arbitrary organic solvent for use.

(E) Examples of organic solvents include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, octane and isoalkanes, 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. The relationship between the amount of the organic solvent (E) used and the preferred method of using the composition is as follows.

The solvent-type curable organopolysiloxane composition of the present invention contains the above-mentioned components (A) to (E) and may further contain (F) a photopolymerization initiator. Component (F) is a component that makes the curable organopolysiloxane composition of the present invention curable by energy rays such as ultraviolet rays. By combining heat curing of the addition reaction with energy ray curing, the curing reaction can be carried out at a lower temperature and in a shorter time. When the heating time needs to be minimized according to the type of substrate and the purpose of use, it is sometimes possible to reduce the damage caused by heat to the sheet substrate, and further improve the adhesion of the peeling layer involved in the present invention to the sheet substrate. Furthermore, it has the advantage of preventing the polysilicone component from migrating from the hardened film surface of the release layer involved in the present invention and causing the release sheet to be contaminated by the polysilicone component (this is called the migration of polysilicone), and further reducing the migration of polysilicone. Here, the curable organic polysilicone composition containing (F) a photopolymerization initiator can be cured by irradiating energy rays after a heat curing reaction, or by irradiating energy rays and then performing a heat curing reaction, or by simultaneously performing heating/energy ray irradiation.

Such component (F) is a well-known compound that generates free radicals by irradiation with energy rays such as ultraviolet rays, 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 1-chloro-3-thiazonone, 3,9-dichloro-3-thiazonone, 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-morpholin-1-propanone, 2,2-dimethoxy-2-phenylacetophenone and diethoxyacetophenone. When the composition of the present invention is cured by ultraviolet light, component (E) is preferably benzophenone, 4-methoxyacetophenone, 4-methylbenzophenone, diethoxyacetophenone and 1-hydroxycyclohexylphenylketone. As particularly preferred component (E), diethoxyacetophenone and 1-hydroxycyclohexyl phenyl ketone can be mentioned.

The photopolymerization initiator (F) may be used alone or in combination. The amount of the photopolymerization initiator 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 component (A). If the amount of component (F) is within the above range, the peeling coating obtained after the composition of the present invention is cured can be cured in a short time at a low temperature, and the transferability of the polysilicone is improved and the physical properties such as strength are excellent.

In addition to the above-mentioned components, other optional components can be added to the solvent-curable organopolysiloxane composition of the present invention within the scope of not impairing the purpose of the present invention. Examples of other optional components 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-based, sulfur-based, and thioether-based; light stabilizers such as triazole-based and benzophenone-based; phosphate-based, halogen-based, Flame retardants such as phosphorus and antimony; 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. Furthermore, the antistatic agent can be any known ionic or non-ionic antistatic agent without particular limitation. From the viewpoint of antistatic, it can be used not only as an additive to the antistatic agent, but also as a surfactant-based, polysilicon-based, organic boron-based, conductive polymer-based, metal oxide-based, and vapor-deposited metal-based antistatic agent for treating the components constituting the peelable sheet or the laminate containing the peelable sheet.

The composition of the present invention can be prepared by uniformly mixing the components (A) to (E), the component (F) selected according to any selection and curing system, and other arbitrary components. The order of addition of the components is not particularly limited. When the composition obtained after mixing is not used immediately, it is preferred to store the mixture of component (A) and component (B) and component (C) separately and mix the two before use. In addition, it is particularly preferred to design a composition that does not crosslink at room temperature by adjusting the blending amount of component (D) in the composition composed of the above-mentioned components, but quickly crosslinks and hardens after heating to a predetermined curing temperature. Furthermore, the relationship between the amount of (E) organic solvent used and the preferred method of use of the present composition is as described below.

[Use as a stripping agent composition or a raw material for a solvent-diluted stripping agent composition] As described above, the solvent-curable organic polysilicone composition of the present invention can be used as a raw material for a solvent-diluted stripping agent composition having excellent workability including transportability in a state where the content of the organic solvent is relatively small. On the other hand, in the production process of the release sheet, by diluting the above-mentioned release agent composition raw material with a large amount of organic solvent, it can be used as a release agent composition that can form a release coating layer with excellent wettability/applicability, good peeling force and excellent stability over time on sheet substrates such as plastic films.

When the composition is used as a raw material of a solvent-dilutable stripping agent composition, it is preferred to design the composition to have a relatively low content of (E) organic solvent, in view of maintaining the overall viscosity of the composition to a level that does not hinder operation and solvent dilution during the production process of the stripping sheet, reducing transportation costs, and reducing the amount of new organic solvent used. In the present invention, component (A) can maintain its wettability/applicability to a sheet substrate and is designed to have a viscosity to a level that allows operation even with a relatively low content of (E) organic solvent. Therefore, the content of (E) organic solvent is in the range of 1 to 50 mass % of the overall composition, and a composition with a relatively high solid content can be designed. In addition, from the viewpoint of reducing the amount of organic solvent used and the operability and solvent dilution in the production process of the exfoliative sheet of the composition, the content of the organic solvent (E) is preferably in the range of 1 to 40 mass % of the entire composition, and more preferably in the range of 2 to 15 mass % and 3 to 12 mass % of the entire composition. Furthermore, if the viscosity range of component (A) exceeds the upper limit, when the content of the organic solvent (E) is less than 50 mass % of the entire composition, the overall viscosity of the composition will be too high, which may hinder the operability in the production process and the solvent dilution including bath adjustment.

The above solvent dilution type stripping agent composition raw material has excellent operability including transportability and can reduce the use of new organic solvents. Therefore, as the entire production process of the stripping sheet, it can suppress environmental pollution and has high usefulness as a separate product or product raw material. In addition, when the following production process is designed, a production process of the stripping sheet with proper use of the solvent dilution type stripping agent composition raw material and low environmental pollution can be provided.

When the composition is used as a stripping agent composition, in order to obtain good coating properties on sheet substrates such as plastic films, the overall viscosity of the composition at 25°C is preferably 20 to 50,000 mPa･s, and in practical terms, the overall viscosity of the composition is particularly preferably 20 to 20,000 mPa･s, 50 to 10,000 mPa･s. This composition can be prepared using the above-mentioned solvent-dilutable stripping agent composition raw materials or the above-mentioned components (A) to (D) and other optional components, and the content of the organic solvent (E) is in the range of 50 to 97.5 mass % of the overall composition. In particular, when the present composition is used as a stripping agent composition, the content of the (E) organic solvent is preferably in the range of 70-95% by weight of the entire composition, and can also be adjusted to be in the range of 80-95% by weight, 85-95% by weight. In addition, when the solvent-diluted stripping agent composition raw material is diluted with an additional organic solvent, the organic solvent used in the stripping agent composition raw material and the organic solvent used in the dilution can be the same or different. For example, the stripping agent composition raw material can be prepared by using toluene as an organic solvent, and in the production process of the stripping sheet, heptane can be used as an additional organic solvent for dilution to prepare the final stripping agent composition. Furthermore, the composition can be formulated as a stripper composition from the outset, and of course it can also be handled as a separate stripper composition product itself.

[Formation of peelable coating and peelable sheet] If the solvent-curable organic polysilicone composition of the present invention is uniformly applied to the surface of various sheet-like substrates, and heated, irradiated with energy rays (such as ultraviolet rays, electron beams, etc.), or a combination of these is performed under sufficient conditions for component (A) and component (B) to undergo a silylation reaction and crosslinking, a peelable coating consisting of a polysilicone film (i.e., cured organic polysilicone) cured on the surface can be obtained.

The type of sheet substrate is not particularly limited, and can be high-grade paper, coated paper, cast paper, synthetic paper, thermal paper, cardboard, corrugated paper, clay-coated paper, polyolefin laminated paper (polyethylene laminated paper), natural fiber cloth, synthetic fiber cloth, artificial leather cloth, metal foil, and plastic film, and plastic film is particularly preferred. The type of synthetic resin used for plastic film is not particularly limited, and can be polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyethylene terephthalate, nylon, cycloolefin polymer, and polymethyl methacrylate. In particular, when heat resistance is required, films of heat-resistant synthetic resins such as polyimide, polyether ether ketone, polyethylene naphthalate (PEN), liquid crystal polyarylate, polyamide imide and polyether sulfone are preferred. In addition, when transparent plastic films are required, transparent materials such as polyethylene, polypropylene, polystyrene, polyvinylidene chloride, polycarbonate, polyethylene terephthalate and PEN can be used. The solvent-curable organic polysilicone composition of the present invention has excellent wettability/coating properties for the above-mentioned plastic films and can form a uniform peeling coating. Furthermore, the shape of the sheet substrate is not particularly limited, and it can be a single sheet or a folded or cylindrical storage shape.

The thickness of the sheet substrate is generally 10-300 µm, preferably 15-200 µm, and particularly preferably 20-125 µm. The solvent-curable organic polysilicone composition has excellent low-temperature curing properties below 100°C, and thus has the following advantages: even thinner synthetic paper or plastic film will hardly be damaged by heating; even substrates with low heat resistance can form the desired peelable coating.

The method of coating the solvent-curable organopolysiloxane composition of the present invention on a sheet substrate can adopt any well-known method, such as gravure coating, rod coating, spray coating, spin coating, doctor blade coating, roll coating, and slit coating. In addition, the curing temperature is preferably in the range of 50 to 200°C, and in consideration of preventing damage to the plastic film and industrial production efficiency, it is preferably in the range of 60 to 150°C. Furthermore, since the composition contains a higher alkenyl group such as a hexenyl group, it has the advantage of excellent low-temperature curing property below 100°C (for example, in the range of 70 to 100°C).

When the solvent-curable organopolysiloxane composition of the present invention is applied to a sheet-like substrate and cured, the thickness of the peeling coating obtained by curing is not particularly limited, but is preferably 0.01 to 3 µm, more preferably 0.03 to 1 µm. If the thickness of the peeling coating is less than 0.01 µm, it may not fully function as a peeling layer. On the other hand, if the thickness of the peeling coating exceeds 3 µm, agglomeration may occur when the obtained peeling sheet is rolled into a tube.

The peeling resistance value of the peeling coating formed by curing the solvent-curable organopolysiloxane composition of the present invention is small, and it has a light peeling force or slight adhesion to the substrate. Compared with the peeling layer formed by using vinyl or the like other than component (A), it has the advantage of less change in peeling force over time. Therefore, in addition to peeling paper, the peeling sheet formed by using the composition of the present invention can be used for one or more purposes selected from protective films, peeling films for dielectric ceramic layer molding materials, separator films for adhesives, and separator films for functional films.

[Method for producing a peelable sheet with low environmental pollution] As described above, the solvent-curable organic polysilicone composition of the present invention can be used as a raw material for a solvent-diluted peelable composition with excellent operability including transportability under a state where the content of organic solvent is relatively low, thereby providing a method for producing a peelable sheet with low environmental pollution in the overall process while reducing transportation costs and the amount of new organic solvent used.

Specifically, the peelable sheet of the present invention can be obtained by a manufacturing method having the following process. Here, the type of substrate is not particularly limited, and the same substrate as the sheet substrate can be listed, and plastic film is particularly preferred. Process (I): Add the same or different (E) organic solvent to the above-mentioned solvent-type curable organic polysilicone composition, and prepare a coating bath of the peeling agent composition so that the overall viscosity of the composition at 25°C is 20~50,000 mPa･s; Process (II): a process of applying the stripping agent composition prepared in process (I) onto a substrate such as a plastic film; Process (III): a process of hardening the stripping agent composition applied in process (II) on a substrate such as a plastic film at 50~200℃ to form a stripping coating; and Optional process (IV): a process of recovering the (E) organic solvent volatilized in process (III).

Here, the dilution amount of the organic solvent, the coating method on the plastic film, and the composition of the peeling sheet are as described above, and the curing conditions of process (II) or process (III) can be designed to be more preferably within the above range. In addition, the process for recovering (E) the organic solvent can be arbitrary and can be easily achieved by using a well-known solvent recovery method. As the solvent recovery method of the present invention, a method of separating from air coexisting with solvent vapor, that is, a condensation method, a compression method, an absorption method, an adsorption method, and a combination of these methods can be used. The above methods can be selected by considering the composition, physical properties, chemical properties, concentration, production volume (processing volume), impurities contained, desired recovery rate, and characteristics of the recovered (E) organic solvent of the solvent vapor. In addition, the organic solvent purification method proposed by the applicant of this application in Japanese Patent Publication No. 2010-018751, etc., can also be used as needed. In particular, according to process (IV), by recycling the (E) organic solvent, it is sometimes possible to more appropriately solve the problem of reducing environmental pollution, which is the purpose of the present invention. [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 means parts by mass. In addition, the vinyl ( _CH2 =CH-) part refers to the part containing a carbon-carbon double bond in the alkenyl group bonded to the silicon atom, that is, the ethylene ( _CH2 =CH-) group part. The content of the vinyl part in the overall molecular weight is expressed in mass %, and the alkenyl group is a vinyl group, which is referred to as "vinyl content". The viscosity is a value measured at 25°C. When measuring the viscosity, a cone plate rotational viscometer DV1 manufactured by Brookfield was used.

[Evaluation of coating properties] Each curable organopolysilicone composition was coated on the surface of a PET film (Mitsubishi Chemical Co., Ltd., 50 micrometers thick) using a Mayer bar in an amount of 0.2 g/ ^m2 in terms of solid content. The substrate surface coated with the above composition was air-dried and then heated in a hot air circulation oven set at 130°C for 30 seconds to form a cured layer of organopolysilicone (= peelable coating) on the surface of the PET film. The state of the peelable coating at this time was visually observed and judged as follows. In practice, B and C can be evaluated as having sufficient wettability/coating properties. A: There is a lot of fine-grained shrinkage and the coating is uneven. B: There is only a small amount of shrinkage at the end and the coating is almost uniform.

C: No shrinkage, uniform coating [Peeling force evaluation] Each curable organopolysilicone composition was applied to the surface of a PET film (Mitsubishi Chemical Co., Ltd., 50 micron thick) using a Mayer bar at a solid conversion amount of 0.2 g/m ^2. The substrate surface coated with the above composition was air-dried and then heated in a hot air circulation oven set at 130°C for 30 seconds to form a curing layer of organopolysilicone (= peeling coating layer) on the surface of the PET film. After curing at 23°C and 50% humidity for 3 days, an acrylic adhesive [TOYOCHEM Co., Ltd., trade name Oribain BPS5127] was evenly applied to the cured film surface using an applicator to a wet thickness of 70 µm, and dried at 70°C for 2 minutes. Then, a PET film (Mitsubishi Chemical Co., Ltd., 50 micron thick) was laminated on it, a load of 20 g/cm ² was applied, and it was left at 23°C and 50% humidity for 1 day. Then, a TENSILON tensile tester was used to measure the peeling force when the laminated PE film was stretched in the 180° direction at a speed of 0.3m/min, and the result was evaluated as the initial peeling force. On the other hand, the hardened film was obtained as described above, and after being left at 70°C for 3 days, the peeling force was measured using a TENSILON tensile tester as described above, and the result was evaluated as the peeling force over time. The width of the samples was 5 cm.

[Preparation Example 1] 5.00 parts of (A-1) polydimethylsiloxane having hexenyl groups at both ends of the molecular chain and in the side chains (viscosity 18400 mPa･s, content of vinyl (CH ₂ =CH-) part in the hexenyl group 0.82 mass %), and (B) 0.12 parts of methyl hydropolysiloxane (the content of hydrogen in the SiH group is 1.6%) with trimethylsiloxy groups capping both ends of the molecular chain of mPa･s, 0.12 parts of (C) chloroplatinic acid･1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (the platinum metal content is 0.6 mass%), (D) 0.01 parts of methylbutynol, and (E) 95.00 parts of a mixed solvent of 50 parts:50 parts of toluene and methyl ethyl ketone were uniformly mixed to obtain a curable organopolysiloxane composition (1).

[Preparation Example 2] A curable organopolysiloxane composition (2) was obtained by the method described in Example 1 except that 5.00 parts of polydimethylsiloxane (viscosity 400 mPa･s, content of vinyl (CH ₂ =CH-) moieties in the hexenyl groups 0.85 mass %) having hexenyl groups at both ends of the molecular chain and in the side chains (A-2) was used instead of component (A-1).

[Preparation Example 3] A curable organopolysiloxane composition (3) was obtained by the method described in Example 1 except that 5.00 parts of polydimethylsiloxane (viscosity 10,000 mPa･s, content of vinyl (CH ₂ =CH-) moiety 0.77 mass %) having vinyl groups at both ends of the molecular chain and in the side chains (A-3) was used instead of component (A-1).

[Preparation Example 4] A curable organopolysiloxane composition (4) was obtained by the method described in Example 1 except that 5.00 parts of (A-4) polydimethylsiloxane having hexenyl groups on the molecular side chains (plasticity 120, content of vinyl (CH ₂ =CH-) parts in the hexenyl groups 0.79 mass %) was used instead of component (A-1).

[Preparation Example 5] 2.50 parts of (A-4) polydimethylsiloxane having hexenyl groups on the molecular side chains (plasticity 120, content of vinyl (CH ₂ =CH-) groups in the hexenyl groups 0.79 mass %), and (B) 0.06 parts of methyl hydropolysiloxane (the content of hydrogen in the SiH group is 1.6%) with trimethylsiloxy groups capping both ends of the molecular chain of mPa･s, 0.06 parts of (C) chloroplatinic acid･1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (the platinum metal content is 0.6 mass%), 0.005 parts of (D) methylbutynol and 97.50 parts of a mixed solvent of (E) 50 parts:50 parts of toluene and methyl ethyl ketone were uniformly mixed to obtain a curable organopolysiloxane composition (5).

[Preparation Example 6] 87.72 parts of (A-1) polydimethylsiloxane having hexenyl groups at both ends of the molecular chain and in the side chain (viscosity 18400 mPa･s, content of vinyl ( _CH2 =CH-) parts in the hexenyl groups 0.82 mass %), 2.11 parts of (B) methyl hydropolysiloxane having a molecular chain end-capped with trimethylsiloxy groups at both ends (content of hydrogen parts in SiH groups 1.6%) with a viscosity of 20 mPa･s, 0.17 parts of (D) methylbutynol and 10.00 parts of (E) toluene were uniformly mixed to obtain a curable organopolysiloxane composition (6).

[Preparation Example 7] 29.23 parts of (A-4) polydimethylsiloxane having hexenyl groups on the molecular side chains (plasticity 120, content of vinyl ( _CH2 =CH-) parts in the hexenyl groups 0.79 mass %), 0.71 parts of (B) methyl hydropolysiloxane having a molecular chain end-capped with trimethylsiloxy groups at both ends (content of hydrogen parts in SiH groups 1.6%) with a viscosity of 20 mPa･s, (D) 0.06 parts of methylbutynol and (E) 70.00 parts of toluene were uniformly mixed to obtain a curable organopolysiloxane composition (7).

[Example 1, Comparative Examples 1-4] The curable organopolysiloxane compositions (1)-(5) prepared in Preparation Examples 1-5 were evaluated according to the method described in [Evaluation of Coating Properties]. In addition, their peeling forces were evaluated according to the method described in [Evaluation of Peeling Force]. The results are shown in Table 1.

[Table 1] *: Poor coating, uneven surface, unable to measure **: Omitted because only the solvent content was different from Comparative Example 4 (=same coating amount).

As shown in Table 1, when the low-viscosity component (A-2) is used, its coating property (= wettability) is not sufficient. Compared with Comparative Examples 3 and 4 using colloidal silicone components, Example 1 has a roughly uniform coating property and a small change in peeling force over time, so it has the advantages of not using a colloidal silicone component and having excellent peeling force and coating property. Furthermore, in Comparative Example 2 using a vinyl group instead of a hexene group, although the coating property is improved to a certain extent, the change in peeling force over time is large, which is not practically suitable.

[Example 2, Comparative Example 5] The viscosity of each curable organopolysiloxane composition (6) and (7) prepared in Preparation Examples 6 and 7 was measured and shown in Table 2. [Table 2]

As shown in Table 2, in Comparative Example 5 using component (A-4), when designing a composition with an operable viscosity of 5500 mPa･s, the effective content of polysilicone is 30% by mass, and a large amount of organic solvent (toluene) must be used. In contrast, in Example 2 using component (A-1), when designing a composition with an operable viscosity of 5500 mPa･s, the effective content of polysilicone is 90% by mass, and the raw material of the solvent-diluted stripping agent composition can be designed with a high effective part concentration. Furthermore, in this composition, of course, the (C) silylation catalyst can be added in the amount required for hardening and at the desired timing, similarly to other embodiments.

without

without

Claims (11)

A solvent-dilutable stripping agent composition raw material comprises the following components: (A) a molecule having at least 3 alkenyl groups with carbon atoms of 4 to 12, wherein the content of the vinyl (CH ₂ =CH-) part in the alkenyl group is 0.1 to 5.0 mass % relative to the total molecular weight of the organic polysilicone, and the viscosity at 25°C is 5,000 to 100,000 mPa. (B) an organic hydropolysiloxane having two or more silicon-bonded hydrogen atoms (Si-H) in one molecule; (C) a catalytic amount of a silylation catalyst; (D) a silylation inhibitor; and (E) an organic solvent in an amount of 2 to 15 mass % of the total composition, wherein the same or different organic solvent (E) is further added for use in forming a stripping coating. As described in item 1 of the patent application scope, the solvent-diluted stripping agent composition raw material, wherein component (A) is one or more organic polysilicone having a viscosity within the range of 10,000 to 50,000 mPa.s at 25°C. As described in item 1 or 2 of the scope of the patent application, the solvent-diluted stripping agent composition raw material, wherein component (A) is an organic polysilicone containing a hexenyl group as the alkenyl group with 4 to 12 carbon atoms, and the content of the organic polysilicone having an alkenyl group with less than 4 carbon atoms in the composition is less than 5.0 mass % of component (A). As described in the solvent-diluted stripper composition raw material of item 1 or 2 of the patent application, the amount of hydrogen atoms bonded to silicon atoms in component (B) is in the range of 1.0 to 10.0 mol relative to 1 mol of carbon-carbon double bonds in component (A). The solvent-diluted stripping agent composition raw material described in item 1 or 2 of the patent application scope is used in the formation of the stripping coating. As described in item 1 or 2 of the patent application scope, the solvent-diluted stripping agent composition raw material, wherein the overall viscosity of the composition at 25°C is 20~50,000mPa.s. A peelable sheet having a peelable coating formed by hardening the solvent-diluted peeling agent composition raw material described in any one of items 1 to 6 of the patent application scope on at least one surface of the sheet-like substrate. As described in item 7 of the patent application, the releasable sheet, wherein the sheet-like substrate is a plastic film. The peelable sheet as described in item 7 or 8 of the patent application scope is used for one or more purposes selected from a protective film, a peeling film for a dielectric ceramic layer molding material, a separator film for an adhesive, and a separator film for a functional film. A method for producing a release sheet, which is a method for producing a release sheet as described in any one of items 7 to 9 of the patent application, comprising the following process: process (I): in a molecule containing: (A) at least 3 alkenyl groups with carbon atoms of 4 to 12, wherein the content of the vinyl ( _CH2 =CH-) part in the alkenyl group is 0.1 to 5.0 mass % relative to the total molecular weight of the organic polysilicone, and the viscosity at 25°C is 5,000 to 100,000 mPa. s; (B) an organic hydropolysiloxane having two or more silicon-bonded hydrogen atoms (Si-H) in one molecule; (C) a catalytic amount of a silylation catalyst; (D) a silylation inhibitor; and (E) an organic solvent in an amount of 2 to 15 mass % of the total composition. The same or different organic solvent (E) is added to the raw materials of the stripping agent composition to prepare a coating bath of the stripping agent composition so that the viscosity of the composition as a whole is 20 to 50,000 mPa at 25°C. s, the solvent-diluted stripping agent composition raw material is used for the formation of a stripping coating, and the same or different (E) organic solvent is further added for use; process (II): a process of applying the stripping agent composition prepared in process (I) to a substrate; and process (III): a process of hardening the stripping agent composition applied in process (II) on the substrate at a temperature of 50-200° C. to form a stripping coating. The method for manufacturing a release sheet as described in Item 10 of the patent application further comprises the following process: Process (IV): a process for recovering the (E) organic solvent volatile in process (III).