KR102610344B1 - silicone rubber composition - Google Patents

Abstract

The present invention provides (A) diorganopolysiloxane having two or more alkenyl groups in one molecule; (B) an organopolysiloxane resin consisting essentially of R ₃ SiO _1/2 units and SiO _4/2 units, wherein each R is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups, but wherein at least one R is an alkenyl group and the molar ratio of R ₃ SiO _1/2 units to SiO _4/2 units is 0.5 to 1.4; (C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule; (D) Silica fine powder; and (E) a hydrosilylation reaction catalyst. The silicone rubber composition can be quickly cured by heating and can form a cured product that exhibits excellent adhesion to organic resins with excellent anchorage.

Description

silicone rubber composition

The present invention relates to silicone rubber compositions.

Silicone rubber compositions curable by hydrosilylation reactions are used in a variety of industries. Recently, silicone rubber compositions have been evaluated in applications such as automotive, electronic/electrical, and medical, especially in applications that integrate silicone and organic resin into a one-piece. Thermoplastic resins such as PBT, polycarbonate, polyamide, etc. have usually been used as organic resins, and in the case of thermosetting resins such as polyurethane, epoxy resin, and phenol novolak resin, adhesion to silicone is not necessarily easy. In particular, when polyurethanes are used together with silicones due to the specific characteristics of polyurethanes for wear properties and low permeability to water, oils and salts, complex pretreatments for silicones as base materials are required, for example plasma treatment, primers. Application or UV treatment was required. In recent years, there have been various proposals and practical applications for using so-called self-adhesive silicone rubber compositions, which are silicone rubber compositions with adhesive properties by applying directly to the surface of the base resin without applying treatments such as ozone or primer. do.

For this reason, Patent Document 1 is an organopolysiloxane having two or more alkenyl groups in one molecule; Organohydrogenpolysiloxanes having two or more silicon-bonded hydrogen atoms in one molecule; organosilicon compounds having aromatic hydrocarbon groups and silicon-bonded alkoxy groups; An adhesive silicone rubber composition comprising an organometallic compound for condensation reaction, an organopolysiloxane resin, and a hydrosilylation reaction catalyst is proposed, and Patent Document 2 includes an organopolysiloxane having two or more alkenyl groups in one molecule; Organosilicon compounds containing one or more phenylene skeletons and one or more silicon-bonded hydrogen atoms in one molecule; Organohydrogenpolysiloxanes that have two or more silicon-bonded hydrogen atoms in one molecule and do not have a phenylene skeleton; and a hydrosilylation reaction catalyst.

However, some problems arise such as insufficient curability and adhesion to thermosetting resins.

US Patent Application Publication No. 2012/0123051 A1 US Patent Application Publication No. 2014/0179863 A1

It is an object of the present invention to provide a silicone rubber composition that can be quickly cured by heating and can form a cured product that exhibits excellent adhesion to thermosetting resins with excellent anchorage.

The silicone rubber composition of the present invention,

(A) diorganopolysiloxane having two or more alkenyl groups in one molecule;

(B) an organopolysiloxane resin consisting essentially of R ₃ SiO _1/2 units and SiO _4/2 units, wherein each R is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups, but At least one R is an alkenyl group, and the molar ratio of R ₃ SiO _1/2 units to SiO _4/2 units is 0.5 to 1.4, in an amount of 5 to 20% by mass of the sum of components (A) to (D). , the organopolysiloxane resin;

(C) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, wherein the moles of silicon-bonded hydrogen atoms in component (C) relative to the alkenyl groups in components (A) and (B) the organohydrogenpolysiloxane in an amount such that the ratio ranges from 0.5 to 20;

(D) silica fine powder in an amount of 5 to 20% by mass of the total of components (A) to (D); and

(E) Catalytic amount of hydrosilylation reaction catalyst

Includes.

The silicone rubber composition of the present invention is characterized by rapid curing properties and excellent adhesion to various organic resins with excellent anchorage.

[Content of the invention]

Component (A) is a diorganopolysiloxane having two or more alkenyl groups in one molecule. Examples of alkenyl groups in component (A) include alkenyl groups having 2 to 12 carbon atoms, such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group. , nonenyl group, decenyl group, undecenyl group, and dodecenyl group, with vinyl group being preferred. Examples of groups bonded to a silicon atom other than the alkenyl group in component (A) include alkyl groups having 1 to 12 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group; Aryl groups having 6 to 20 carbon atoms, such as phenyl group, tolyl group, xylyl group, and naphthyl group; Aralkyl groups having 7 to 20 carbon atoms, such as benzyl group, phenethyl group, and phenylpropyl group; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atoms, chlorine atoms, or bromine atoms. The silicon atoms in component (A) may also have small amounts of hydroxyl groups within the extent that the object of the present invention is not impaired.

The molecular structure of component (A) is essentially linear. However, component (A) may be partially branched and linear without impairing the object of the present invention. Component (A) may be a single organopolysiloxane, or may be a mixture of two or more types of organopolysiloxane. Examples of such component (A) include dimethylpolysiloxane with both molecular ends capped with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer with both molecular ends capped with dimethylvinylsiloxy groups, and both molecular ends Dimethylsiloxane-methylphenylsiloxane copolymer capped with dimethylvinylsiloxy groups, methylphenylpolysiloxane with both molecular ends capped with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinyl with both molecular ends capped with trimethylsiloxy groups. Siloxane copolymers, dimethyl-siloxane-methylvinylsiloxane-methylphenylsiloxane copolymers with both molecular ends capped with trimethylsiloxy groups, and mixtures of two or more types thereof.

In order to increase adhesion to organic resins with excellent anchorage, component (A) has two or more alkenyl groups in one molecule and has a viscosity at 25° C. of 1 to 500 Pa·s, preferably a viscosity of 1. to 50 Pa·s diorganopolysiloxane. This means that when the viscosity is above the lower limit of the range described above, the composition forms a cured product exhibiting good mechanical properties, and when the viscosity is below the upper limit of the range described above, the composition forms a cured article exhibiting adequate adhesion on the organic resin. Because it forms. The viscosity at 25°C of the organopolysiloxane can be determined based on JIS K 7117-1 using, for example, a B type viscometer.

Component (B) is an organopolysiloxane resin consisting essentially of R ₃ SiO _1/2 units and SiO _4/2 units. However, component (B) may also have small amounts of R ₂ SiO _2/2 units and RSiO _3/2 units without impairing the object of the present invention. The molar ratio of R ₃ SiO _1/2 units to SiO _4/2 units is 0.5 to 1.4, preferably 0.6 to 1.4, or 0.6 to 1.1. This means that when this ratio is above the lower limit of the range described above, the composition forms a cured product exhibiting good mechanical properties, and when the ratio is below the upper limit of the range described above, the composition forms a cured article exhibiting adequate adhesion on the organic resin. Because it does.

wherein each R is independently selected from the group consisting of a monovalent hydrocarbon group and a monovalent halogenated hydrocarbon group. Examples of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups in component (B) include alkyl groups having 1 to 12 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group; Alkenyl groups having 2 to 12 carbon atoms, such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, and dodecenyl group; Aryl groups having 6 to 20 carbon atoms, such as phenyl group, tolyl group, xylyl group, and naphthyl group; Aralkyl groups having 7 to 20 carbon atoms, such as benzyl group, phenethyl group, and phenylpropyl group; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atoms, chlorine atoms, or bromine atoms. However, more than one R in a molecule is an alkenyl group. The silicon atoms in component (B) may also have a small amount of hydroxyl groups within the extent that the object of the present invention is not impaired.

Component (B) is used in an amount of 5 to 20% by mass, preferably 5 to 15% by mass, of the total of components (A) to (D). This means that when the content of component (B) is at least the lower limit of the range described above, the composition forms a cured product exhibiting good anti-scratch and mechanical properties on the base film, and the composition forms a cured product exhibiting good anti-scratch and mechanical properties on the base film, and when the content of component (B) is at least the lower limit of the range described above. This is because when it is below the upper limit, the composition forms a cured product that exhibits appropriate adhesion on the organic resin film.

Component (C) is the crosslinking agent of the composition of the present invention and is an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule. Examples of groups bonding to silicon atoms other than hydrogen atoms in component (C) include alkyl groups having 1 to 12 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl. group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group; Aryl groups having 6 to 20 carbon atoms, such as phenyl group, tolyl group, xylyl group, and naphthyl group; Aralkyl groups having 7 to 20 carbon atoms, such as benzyl groups, phenethyl groups, and phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atoms, chlorine atoms, or bromine atoms. Furthermore, the silicon atoms in component (C) may have small amounts of hydroxyl groups or alkoxy groups, such as methoxy groups or ethoxy groups, without impairing the object of the present invention.

Examples of the molecular structure of component (C) include straight chain, partially branched straight chain, branched chain, cyclic, and three-dimensional network structures, and the molecular structure is preferably partially branched straight chain, branched chain, or three-dimensional network structure. am.

The viscosity of component (C) at 25°C is not limited, but is preferably not more than 1000 mPa·s, in the range of 0.1 to 500 mPa·s, or in the range of 0.5 to 500 mPa·s. This is because when the viscosity is above the lower limit of the range described above, the composition forms a cured product exhibiting good mechanical properties, and when the viscosity is below the upper limit of the range described above, the composition is easy to handle. This viscosity can be determined, for example, by measurement using a B-type viscometer according to JIS K 7117-1.

Examples of such component (C) include 1,1,3,3-tetramethyldisiloxane;

1,3,5,7-tetramethylcyclotetrasiloxane, tris(dimethylhydrogensiloxy)methylsilane, tris(dimethylhydrogensiloxy)phenylsilane, 1-glycidoxypropyl-1,3,5 ,7-Tetramethylcyclotetrasiloxane, 1,5-glycidoxypropyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1-glycidoxypropyl-5-trimethoxysilylethyl-1,3 , 5,7-tetramethylcyclotetrasiloxane, methylhydrogenpolysiloxane, both molecular ends capped with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer, both molecular ends capped with trimethylsiloxy groups, Dimethylpolysiloxane, molecular ends capped with dimethylhydrogensiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer, both molecular ends capped with dimethylhydrogensiloxy groups, both molecular ends capped with trimethylsiloxy groups methylhydrogensiloxane-diphenylsiloxane copolymer, methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymer with both molecular ends capped with trimethylsiloxy groups, (CH ₃ ) ₂ HSiO _1/2 units and SiO Copolymers consisting of _4/2 units, (CH ₃ ) ₂ HSiO _1/2 units, SiO _4/2 units, and (C ₆ H ₅ )SiO _3/2 units, and two or more types thereof. Includes mixtures.

Component (C) has a molar ratio of silicon-bonded hydrogen atoms in component (C) to alkenyl groups in components (A) and (B) in the range from 0.5 to 20, preferably in the range from 0.5 to 15, and especially It is preferably used in an amount ranging from 0.5 to 10. This means that when the content of component (C) is above the lower limit of the range described above, the composition forms a cured layer exhibiting good mechanical properties, and when the content is below the upper limit of the range described above, the composition forms adequate adhesion on the organic resin. This is because it forms a hardened product that exhibits resistance. Here, the content of silicon-bonded hydrogen atoms in component (C) can be determined by analytical methods such as, for example, Fourier transform infrared spectrophotometry (FT-IR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). can be determined by

Component (D) is a fine silica powder to increase the mechanical properties of the resulting cured product. Component (D) is dry silica, wet silica, calcined silica, or that obtained by treating the surface of such silica powder with an organosilicon compound, such as an organoalkoxysilane, an organohalosilane, or an organosilazane. It can be exemplified by the same powder. The BET specific surface area of the silica fine powder is not limited, but is preferably 50 m ² /g or more, 100 m ² /g or more, or 200 m ² /g or more.

Component (D) is used in an amount of 5 to 20% by mass, preferably 10 to 20% by mass, of the total of components (A) to (D). This means that when the content of component (D) is at least the lower limit of the range described above, the composition forms a cured product exhibiting good scratch resistance and mechanical properties on the base film, and when the content is below the upper limit of the range described above, the composition This is because it forms a cured product that exhibits appropriate adhesion on the organic resin film.

Component (E) is a hydrosilylation reaction catalyst to promote curing of the composition, examples include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts. In particular, component (E) is preferably a platinum-based catalyst so as to dramatically accelerate curing of the composition. Examples of platinum-based catalysts include platinum fine powder, chloroplatinic acid, alcoholic solution of chloroplatinic acid, platinum-alkenylsiloxane complex, platinum-olefin complex, and platinum-carbonyl complex, with platinum-alkenylsiloxane complex being preferred. .

In the present composition, the content of component (E) is not particularly limited as long as it is an amount effective to promote curing of the composition, but the content is preferably 0.01% by mass of the catalyst metal in component (E) relative to the composition. The amount is in the range of 0.01 to 500 ppm, more preferably 0.01 to 100 ppm, and particularly preferably 0.01 to 50 ppm. This is because the curing reaction of the resulting composition is promoted when the content of component (E) is within the above-mentioned range.

The silicone rubber composition of the present invention may include (F) a reaction inhibitor. Component (F) is an alkyne alcohol, such as 1-ethynyl-cyclohexan-1-ol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, and 2-phenyl-3-butyn-2-ol; ene-yne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetra. Illustrated by siloxane, or benzotriazole. The content of component (F) is not particularly limited, but is preferably in the range of 0.0001 to 5 parts by mass with respect to a total of 100 parts by mass of components (A) to (D) described above.

The silicone rubber composition of the present invention may contain an organoalkoxysilane to further improve adhesion to thermosetting resin. Examples of silanes are vinyl trimethoxysilane, vinyl-triethoxysilane, vinyl tris(β-methoxyethoxy)silane, vinyl diethoxy methylsilane, allyl trimethoxysilane, acryloyloxymethyl trimethoxy. Silane, γ-methacryloxypropyl trimethoxysilane, γ-glycidyloxypropyl trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, N-(β-aminoethyl )-γ-aminopropyl trimethoxysilane, γ-mercaptopropyl trimethoxysilane, and α-(ethoxycarbonyl)ethyl trimethoxysilane. Particular preference is given to γ-methacryloxypropyl trimethoxysilane and γ-glycidyloxypropyl trimethoxysilane. These may be used independently, or two or more of them may be used. The amount of organoalkoxysilane is 0.01 to 20 parts by mass, preferably 0.05 to 20 parts by mass, per 100 parts by mass of component (A). If it is less than 0.01 parts by mass, it is difficult to obtain the effect of the alkoxysilane, and use of more than 20 parts by mass is undesirable because release of the cured material from the mold worsens and changes in hardness are observed after curing.

In the preparation method described above, organic solvents can be used. Examples of organic solvents that can be used include aromatic or aliphatic hydrocarbons and mixtures of two or more thereof. Examples of preferred organic solvents include toluene and xylene.

The silicone rubber composition of the present invention is suitable for obtaining an integral mold with an organic resin. Examples of thermosetting resins are polyurethanes, phenolic resins, epoxy resins, urea resins, unsaturated polyester resins, melamine resins, alkyd resins, and thermosetting polyimides.

The integral molding method for the silicone rubber composition onto the thermosetting resin described above includes heating a silicone rubber composition disposed on the molded thermosetting resin having a desired shape at a curing temperature; pressing the silicone rubber composition onto the thermoset resin at a temperature below the curing temperature; and injection molding the thermosetting resin into a mold and then injecting the silicone rubber composition. The silicone rubber composition may be liquid, putty-like, or paste-like, but is preferably liquid or paste-like to facilitate molding. The curing conditions for the silicone rubber composition must be a temperature and time that does not cause changes in shape or quality for strong adhesion to the thermosetting resin. Although these conditions vary depending on the type of resin, an integral molding can be obtained under conditions of a temperature of 80 to 180° C. and a time of 0.2 to 30 minutes.

The silicone rubber composition of the present invention can be used as a coating agent on the surface of a thermosetting resin. Depending on the coating method, diluents may be added to adjust viscosity. There are no restrictions on the diluent, and various organic solvents such as toluene, xylene, n-hexane, ethanol, and iso-propanol can be used. There are no restrictions on the coating method, and it is preferred to apply screen printing, spray coating or dip-coating. The coated film can be obtained by coating on a thermosetting resin and drying at 50 to 200°C for 5 minutes to 3 hours.

Although curing of the present silicone rubber composition occurs at room temperature or under heating, it is preferred to heat the composition to achieve rapid curing. The heating temperature is preferably 50 to 200°C.

Example

The silicone rubber composition of the present invention will be described in detail below using examples and comparative examples. Viscosity is the value at 25°C. The properties of the silicone rubber composition and its cured product were measured as follows.

[Curability of silicone rubber composition]

The silicone rubber composition is coated on a polyurethane film to a thickness of 500 μm and cured at 150° C. for 2 to 3 minutes. The curability of the silicone rubber composition is confirmed by rubbing test and fluid transfer by covering PET film. Another method is to check the fluid movement between the silicone rubber and the organic resin after cutting the film. If the silicone rubber composition does not cure and the uncured fluid from the uncured silicone rubber composition bleeds onto the finger or onto the covered PET film by rubbing test, the curability is rated as "X". Otherwise, the hardenability is rated as “O”.

[Adhesion properties of cured material]

Anchorage between polyurethane and silicone rubber is confirmed by edge elongation and legging adhesion tests. After the silicone rubber composition is cured on a polyurethane film to a thickness of 500 μm at 150° C. for 2 to 3 minutes, the edge surface is stretched to check separation or gap between the polyurethane and the cured product. If the cured product has good anchorage on the polyurethane substrate and no separation tears are observed, the adhesion properties are rated as "O". Otherwise, the curability is evaluated as “X”.

The second method is the legging adhesion test, in which a defect or crack is created on the cured material with a knife and then stretched from the defect or crack. If the cured product has good anchorage on the polyurethane substrate and no separation tears are observed, the adhesion properties are rated as "O". Otherwise, the curability is evaluated as “X”.

[Example 1]

65.8 parts by mass of dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both molecular ends and having a viscosity of 40 Pa·s, 8.4 parts by mass of dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both molecular ends and having a viscosity of 2 Pa·s Part, the average unit formula:

[(CH ₂ =CH)(CH ₃ ) ₂ SiO _1/2 ] _0.05 [(CH ₃ ) ₃ SiO _1/2 ] _0.37 (Si0 _4/2 ) _0.58

6.6 parts by mass of an organopolysiloxane resin, 13.6 parts by mass of dry silica with a BET specific surface area of 255 m ² /g, dimethylsiloxane and methyl, both molecular ends capped with trimethylsiloxy groups and a viscosity of 5 mPa·s. 5.1 parts by mass of a copolymer of hydrogensiloxane (an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component per vinyl group in the above two dimethylpolysiloxane and organopolysiloxane resins is 6.2), 1-ethynyl-cyclohexane- 0.05 parts by mass of 1-ol, and platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane A silicone rubber composition was produced by mixing 0.80 parts by mass of a solution (a solution containing 0.5% by mass of platinum). Next, the cured product of the silicone rubber composition was evaluated. The results are shown in Table 1.

[Example 2]

56.5 parts by mass of dimethylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups and having a viscosity of 40 Pa·s, 14.0 parts by mass of dimethylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups and having a viscosity of 2 Pa·s Part, the average unit formula:

[(CH ₂ =CH)(CH ₃ ) ₂ SiO _1/2 ] _0.05 [(CH ₃ ) ₃ SiO _1/2 ] _0.37 (SiO _4/2 ) _0.58

11.0 parts by mass of an organopolysiloxane resin, 10.9 parts by mass of dry silica with a BET specific surface area of 255 m ² /g, dimethylsiloxane and methyl, both molecular ends capped with trimethylsiloxy groups and a viscosity of 5 mPa·s. 7.2 parts by mass of a copolymer of hydrogensiloxane (an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component per vinyl group in the above two dimethylpolysiloxane and organopolysiloxane resins is 6.3), 1-ethynyl-cyclohexane- 0.05 parts by mass of 1-ol, and platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane A silicone rubber composition was produced by mixing 0.80 parts by mass of a solution (a solution containing 0.5% by mass of platinum). Next, the cured product of the silicone rubber composition was evaluated. The results are shown in Table 1.

[Example 3]

47.9 parts by mass of dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both molecular ends and having a viscosity of 40 Pa·s, 14.0 parts by mass of dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both molecular ends and having a viscosity of 2 Pa·s Part, the average unit formula:

[(CH ₂ =CH)(CH ₃ ) ₂ SiO _1/2 ] _0.05 [(CH ₃ ) ₃ SiO _1/2 ] _0.37 (SiO _4/2 ) _0.58

11.0 parts by mass of an organopolysiloxane resin, 13.2 parts by mass of dry silica with a BET specific surface area of 255 m ² /g, dimethylsiloxane and methyl, both molecular ends capped with trimethylsiloxy groups and a viscosity of 5 mPa·s. 9.5 parts by mass of a copolymer of hydrogensiloxane (an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component per vinyl group in the above two dimethylpolysiloxane and organopolysiloxane resins is 8.6), 4.0 parts by mass of vinyl trimethoxysilane , 0.05 parts by mass of 1-ethynyl-cyclohexan-1-ol, and platinum-1,3-divinyl-1,1 in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, A silicone rubber composition was produced by mixing 0.40 parts by mass of a solution of 3,3-tetramethyldisiloxane complex (a solution containing 0.5% by mass of platinum). Next, the cured product of the silicone rubber composition was evaluated. The results are shown in Table 1.

[Example 4]

36.9 parts by mass of dimethylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups and having a viscosity of 40 Pa·s, 14.0 parts by mass of dimethylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups and having a viscosity of 2 Pa·s Part, the average unit formula:

[(CH ₂ =CH)(CH ₃ ) ₂ SiO _1/2 ] _0.05 [(CH ₃ ) ₃ SiO _1/2 ] _0.37 (SiO _4/2 ) _0.58

11.0 parts by mass of an organopolysiloxane resin, 13.2 parts by mass of dry silica with a BET specific surface area of 255 m ² /g, dimethylsiloxane and methyl, both molecular ends capped with trimethylsiloxy groups and a viscosity of 5 mPa·s. 16.5 parts by mass of a copolymer of hydrogensiloxane (an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component per vinyl group in the above two dimethylpolysiloxane and organopolysiloxane resins is 15.6), 8.0 parts by mass of vinyl trimethoxysilane , 8.0 parts by mass of vinyl trimethoxysilane, 0.05 parts by mass of 1-ethynyl-cyclohexan-1-ol, and platinum-1 in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, A silicone rubber composition was produced by mixing 0.40 parts by mass of a solution of 3-divinyl-1,1,3,3-tetramethyldisiloxane complex (a solution containing 0.5% by mass of platinum). Next, the cured product of the silicone rubber composition was evaluated. The results are shown in Table 1.

[Comparative Example 1]

12.4 parts by mass of dimethylpolysiloxane with both molecular ends capped with dimethylvinylsiloxy groups and a viscosity of 40 Pa·s, 81.5 parts by mass of dimethylpolysiloxane with both molecular ends capped with dimethylvinylsiloxy groups and with a viscosity of 2 Pa·s parts, 6.1 parts by mass of dry silica with a BET specific surface area of 255 m ² /g, 2.2 parts by mass of a copolymer of dimethylsiloxane and methylhydrogensiloxane, both molecular ends capped with trimethylsiloxy groups and having a viscosity of 5 mPa·s. parts (an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component per vinyl group in the two dimethylpolysiloxanes is 2.1), 0.05 parts by mass of 1-ethynyl-cyclohexan-1-ol, and 1,3- A solution of platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in divinyl-1,1,3,3-tetramethyldisiloxane (solution containing 0.5% by mass of platinum) ) 0.35 parts by mass were mixed to produce a silicone rubber composition. Next, the cured product of the silicone rubber composition was evaluated. The results are shown in Table 1.

[Comparative Example 2]

93.9 parts by mass of dimethylpolysiloxane with both molecular ends capped with dimethylvinylsiloxy groups and a viscosity of 40 Pa·s, 6.1 mass parts of dry silica with a BET specific surface area of 255 m ² /g, and trimethylsiloxy groups at both molecular ends. 0.9 parts by mass of a copolymer of dimethylsiloxane and methylhydrogensiloxane capped with a group and having a viscosity of 5 mPa·s, in an amount such that the molar ratio of silicon-bonded hydrogen atoms in this component per vinyl group in the dimethylpolysiloxane is 2.2 ), 0.05 parts by mass of 1-ethynyl-cyclohexan-1-ol, and platinum-1,3-divinyl-1,1 in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane. , 0.35 parts by mass of a solution of 3,3-tetramethyldisiloxane complex (a solution containing 0.5% by mass of platinum) was mixed to produce a silicone rubber composition. Next, the cured product of the silicone rubber composition was evaluated. The results are shown in Table 1.

[Table 1]

The silicone rubber composition of the present invention has excellent curability and can form a cured product that exhibits excellent adhesion to organic resins with excellent anchorage. Therefore, the silicone rubber composition is suitable as an adhesive for adhesive films or tapes.

Claims (5)

(A) diorganopolysiloxane having two or more alkenyl groups in one molecule;
(B) an organopolysiloxane resin comprising R ₃ SiO _1/2 units and SiO _4/2 units, wherein each R is independently selected from the group consisting of a monovalent hydrocarbon group and a monovalent halogenated hydrocarbon group, but one within one molecule wherein R is an alkenyl group, and the molar ratio of R ₃ SiO _1/2 units to SiO _4/2 units is 0.5 to 1.4, in an amount of 5 to 20% by mass of the sum of components (A) to (D), The organopolysiloxane resin;
(C) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, wherein the moles of silicon-bonded hydrogen atoms in component (C) relative to the alkenyl groups in components (A) and (B) the organohydrogenpolysiloxane in an amount such that the ratio ranges from 0.5 to 20;
(D) silica fine powder in an amount of 5 to 20% by mass of the total of components (A) to (D); and
(E) Catalytic amount of hydrosilylation reaction catalyst
A silicone rubber composition comprising:
Provided that the silicone rubber composition does not contain an organosilicon compound having an aromatic hydrocarbon group and an alkoxy group bonded to a silicon atom, and an organometallic compound that may be a catalyst for the condensation reaction of the organosilicon compound. The silicone rubber composition according to claim 1, wherein component (D) is fumed silica having a specific surface area by the BET method of at least 50 m ² /g. The silicone rubber composition according to claim 1 or 2, further comprising (F) a curing inhibitor in an amount of 0.0001 to 5 parts by mass per 100 parts by mass of the total of components (A) to (D). 3. The silicone rubber composition according to claim 1 or 2, for adhesion to organic resins. The silicone rubber composition of claim 4, wherein the organic resin is a thermosetting or thermoplastic polyurethane resin.