JP2021046537A - Addition reaction-curing type silicone composition, cured product of the same, sheet, and optical component - Google Patents

Abstract

To provide an addition reaction-curing type silicone composition giving a cured product excellent in bending resistance.SOLUTION: The addition reaction-curing type silicone composition includes: (A) an organopolysiloxane expressed by a following average composition formula (1) R1n(C6H5)mSiO(4-n-m)/2 (1), where, in the formula, R1 is a univalent hydrocarbon group, an alkoxy group, or a hydroxy group, and 0.1-80 mol% of total R1 is alkenyl groups; (B) a linear organopolysiloxane having a phenyl group bonding to at least two (meth)acryl groups and at least one silicon atom in one molecule; (C) an organopolysiloxane having at least two hydrogen atoms bonding to (a) silicon atom(s) in one molecule, and expressed by a following average composition formula (2) R2aHbSiO(4-a-b)/2 (2), where, in the formula, R2 is a univalent hydrocarbon group excluding an aliphatic unsaturated hydrocarbon group; and (D) a hydrosilylation reaction catalyst.SELECTED DRAWING: None

Description

The present invention relates to an addition-curable silicone composition, a cured product thereof, a sheet using these, and an optical component.

Silicone resin is widely known as a resin with excellent heat / cold resistance, electrical insulation, weather resistance, water repellency, transparency, etc., and is used for electrical / electronic equipment, OA equipment, automobiles, precision equipment, building materials, etc. It is used in various fields.

In recent years, especially in the field of LEDs, organic materials are exposed to high temperatures and high luminosity for a long period of time due to the miniaturization of optical components and the increase in brightness of light sources. Although development has been desired, silicone resin has been confirmed to have superior performance to other organic resin materials in that it has excellent heat resistance and transparency, as well as being resistant to discoloration and physical deterioration. , The use as an optical component material is also expanding.

Among the silicone resins, the addition reaction curable silicone resin composition disclosed in Patent Document 1 is a solvent-free type, has better moldability than a solvent-type condensation-curable silicone varnish, and contains almost all solvents. Since it is not available, it has advantages such as being environmentally friendly. This silicone resin composition becomes a highly hard and highly transparent resin after curing, and is also used as a key top composition because of its good moldability. Further, Patent Document 2 describes a photocoupler, a light emitting diode, etc. by combining a linear organopolysiloxane having an alkenyl group directly linked to a silicon atom, a branched organopolysiloxane, and an organohydrogenpolysiloxane. High-hardness materials that are excellent as protective materials, coating materials, and encapsulants for optical semiconductor elements have been introduced. Further, Patent Document 3 discloses a material having high hardness and high adhesiveness by optimizing the branched-chain organopolysiloxane, organohydrogenpolysiloxane and the adhesive-imparting agent.

However, although these high-hardness and high-transparency silicone resins are excellent in scratch resistance and crack resistance, they have a drawback that they are easily cracked when a thinly processed sheet of silicone resin is bent.

Japanese Patent No. 3344286 Japanese Unexamined Patent Publication No. 2004-143361 Japanese Unexamined Patent Publication No. 2011-25409

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an addition-curable silicone composition that gives a cured product having excellent bending resistance.

In order to solve the above problems, in the present invention,
(A) Organopolysiloxane represented by the following average composition formula (1),
R ¹ _n (C ₆ H ₅ ) _m SiO _{(4-n-m) / 2} (1)
[In the formula, R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group (excluding the unsubstituted phenyl group), alkoxy group or hydroxyl group, and 0.1 to 80 mol% ^{of the total R 1.} Is an alkenyl group, and n and m are 0.1 ≦ n <0.8, 0.2 ≦ m <1.9, 1 ≦ n + m <2, and 0.20 ≦ m / (n + m) ≦ 0. It is a positive number that satisfies 95. ]
(B) A linear organopolysiloxane having at least two (meth) acrylic groups and a phenyl group bonded to at least one silicon atom in one molecule.
(C) Organohydrogenpolysiloxane represented by the following average composition formula (2) and containing at least two hydrogen atoms bonded to a silicon atom in one molecule: an aliphatic substance in the components (A) and (B). An amount in which the ratio of the number of hydrogen atoms bonded to silicon atoms in the component (C) to the number of unsaturated hydrocarbon groups is 0.01 to 0.5.
R ² _a H _b SiO _{(4-ab) / 2} (2)
Wherein, R ² is a substituted identical or different, excluding aliphatic unsaturated hydrocarbon group (excluding an epoxy group-substituted and alkoxy substituted) or unsubstituted monovalent hydrocarbon group, a and b are 0 It is a positive number that satisfies .7 ≦ a ≦ 2.7, 0.01 ≦ b ≦ 1.0, and 0.8 ≦ a + b ≦ 3.0. ]
as well as,
(D) Hydrosilylation reaction catalyst,
Provided is an addition-curable silicone composition characterized by containing.

Such an addition-curable silicone composition of the present invention can provide a cured product having excellent bending resistance.

（式中、ｐは１〜１，０００の正数であり、ｑは１〜１００の正数であり、ｒは２または３である。括弧が付されたシロキサン単位の配列は任意であってよい。） In this case, the component (B) is preferably a linear organopolysiloxane represented by the following formula (3).

(In the formula, p is a positive number from 1 to 1,000, q is a positive number from 1 to 100, and r is 2 or 3. The parenthesized sequence of siloxane units is arbitrary. Good.)

Such an addition-curable silicone composition can provide a cured product having more excellent bending resistance.

Here, it is more preferable that q / (p + q) in the above formula (3) is 0.25 to 1.

With such an addition-curable silicone composition, it is possible to provide a cured product having even more excellent bending resistance.

Further, the addition-curable silicone composition preferably further contains (E) an organic peroxide.

Since the component (E) has an effect of promoting the polymerization of the (meth) acrylic group of the component (B) and increasing the hardness of the cured product, such an addition-curable silicone composition does not impair the flexibility. Can be given a hardened product having a higher hardness.

The present invention also provides a cured silicone product, which is a cured product of the above-mentioned addition-curable silicone composition.

Such a cured silicone product of the present invention has sufficient hardness and excellent bending resistance.

The present invention also provides a sheet made of the above-mentioned cured silicone product. The sheet preferably has a radius of curvature of less than 1.5 mm at which cracks occur when bent at a thickness of 0.2 mm.

Such a sheet of the present invention has sufficient hardness and excellent bending resistance. Therefore, even if the sheet thinly processed with the silicone resin alone is bent, it will not be easily cracked.

The present invention also provides an optical component having the above-mentioned cured silicone product or the above-mentioned sheet.

Such an optical component of the present invention has sufficient hardness and excellent bending resistance, and is therefore suitable for applications requiring flexibility.

The addition-curable silicone composition of the present invention provides a cured product having sufficient hardness and excellent bending resistance. Therefore, the cured product is useful as a surface material for optical components, particularly flexible substrates or flexible panels.

As a result of diligent studies to solve the above problems, the present inventors have found that a specific silicone composition can solve the above problems, and have completed the present invention.

That is, the present invention is an addition-curable silicone composition containing the following components (A) to (D).
(A) Organopolysiloxane represented by the following average composition formula (1),
R ¹ _n (C ₆ H ₅ ) _m SiO _{(4-n-m) / 2} (1)
[In the formula, R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group (excluding the unsubstituted phenyl group), alkoxy group or hydroxyl group, and 0.1 to 80 mol% ^{of the total R 1.} Is an alkenyl group, and n and m are 0.1 ≦ n <0.8, 0.2 ≦ m <1.9, 1 ≦ n + m <2, and 0.20 ≦ m / (n + m) ≦ 0. It is a positive number that satisfies 95. ]
(B) A linear organopolysiloxane having at least two (meth) acrylic groups and a phenyl group bonded to at least one silicon atom in one molecule.
(C) Organohydrogenpolysiloxane represented by the following average composition formula (2) and containing at least two hydrogen atoms bonded to a silicon atom in one molecule: an aliphatic substance in the components (A) and (B). An amount in which the ratio of the number of hydrogen atoms bonded to silicon atoms in the component (C) to the number of unsaturated hydrocarbon groups is 0.01 to 0.5.
R ² _a H _b SiO _{(4-ab) / 2} (2)
Wherein, R ² is a substituted identical or different, excluding aliphatic unsaturated hydrocarbon group (excluding an epoxy group-substituted and alkoxy substituted) or unsubstituted monovalent hydrocarbon group, a and b are 0 It is a positive number that satisfies .7 ≦ a ≦ 2.7, 0.01 ≦ b ≦ 1.0, and 0.8 ≦ a + b ≦ 3.0. ]
(D) Hydrosilylation reaction catalyst

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[Additionally curable silicone composition]
The addition-curable silicone composition of the present invention contains the components (A) to (D) described later. Further, if necessary, other components such as (E) organic peroxide, addition reaction control agent, and adhesiveness improver can be contained.
Hereinafter, each component will be described in detail.

[(A) component]
The component (A) is an organopolysiloxane represented by the following average composition formula (1).
R ¹ _n (C ₆ H ₅ ) _m SiO _{(4-n-m) / 2} (1)
[In the formula, R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group (excluding the unsubstituted phenyl group), alkoxy group or hydroxyl group, and 0.1 to 80 mol% ^{of the total R 1.} Is an alkenyl group, and n and m are 0.1 ≦ n <0.8, 0.2 ≦ m <1.9, 1 ≦ n + m <2, and 0.20 ≦ m / (n + m) ≦ 0. It is a positive number that satisfies 95. ]

The component (A) is preferably a liquid or solid having a viscosity of 10,000 mPa · s or more at 25 ° C. measured by a rotational viscometer, and is preferably a liquid or a liquid of 100,000 mPa · s to 10,000,000 mPa · s. It is more preferably solid. When such a component (A) is used, the mechanical properties of the cured product become better.

As is understood from the fact that 1.0 ≦ n + m <2.0 in the average composition formula (1), the component (A) has at least R ¹ SiO _3/2 units in the _{molecule, (C 6} H). ₅ ) It has a branched or three-dimensional network structure containing one or more of _{SiO 3/2} units and SiO _{4/2 units.}

The group of R ¹ is the same or different, substituted or unsubstituted monovalent hydrocarbon group, alkoxy group or hydroxyl group except for _{C 6} H _{5 group.} Examples of the monovalent hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group and a hexyl group, and a saturated hydrocarbon group such as a cycloalkyl group such as a cyclohexyl group. Arlyl groups other than phenyl groups such as trill group, xsilyl group and naphthyl group, aralkyl groups such as benzyl group and phenylethyl group, vinyl group, allyl group, propenyl group, isopropenyl group, alkenyl group such as butenyl group and the like. Examples thereof include an unsaturated hydrocarbon group and a halogen-substituted hydrocarbon group such as a 3,3,3-trifluoropropyl group.
^{Among these, a methyl group is preferable as the R 1} other than the alkenyl group, and a vinyl group is preferable as the alkenyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

Further, 0.1 to 80%, preferably 0.5 to 50%, of the total number of ^{R 1 is an alkenyl group.} If the number of alkenyl groups is less than 0.1%, the hardness required for the cured product cannot be obtained, and if it is more than 80%, the cured product (silicone resin) becomes brittle because there are too many cross-linking points.

n and m are 0.1 ≦ n <0.8 and 0.2 ≦ m <1.9, and satisfy 1 ≦ n + m <2.0. If n + m is less than 1 or more than 2, the required hardness and strength may not be obtained.
Further, when 0.20 ≦ m / (n + m) ≦ 0.95, preferably 0.30 ≦ m / (n + m) ≦ 0.80, and the number of phenyl groups is out of this range, the machine of the cured product The characteristics may not be obtained and the transparency may be inferior.

The component (A) can be obtained by a known method of hydrolyzing and condensing alkoxysilane, chlorosilane, or the like, but may contain an alkoxy group or a silanol group, if necessary.

Specific examples of the component (A) include those represented by the following formulas.
[(CH ₃ ) (CH ₂ = CH) SiO] _6.2 [(C ₆ H ₅ ) ₂ SiO] _2.5 [(C ₆ H ₅ ) SiO _3/2 ] ₇

The component (A) may be used alone or in combination of two or more.

[(B) component]
The component (B) is a linear organopolysiloxane having at least two (meth) acrylic groups and a phenyl group bonded to at least one silicon atom in one molecule.

In the present invention, the (meth) acrylic group means an acrylic group or a methacrylic group. Examples of the (meth) acrylic-containing group include an acryloyloxy group, a methacryloyloxy group, an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, a methacryloyloxyalkyloxy group, and the like.
The number of carbon atoms of the alkyl (alkylene) moiety contained in these groups is not particularly limited, but is preferably 1 to 10, more preferably 1 to 5, and even more preferably 2 or 3.

Among these, an acrylic group is preferable from the viewpoint that the hydrosilylation reaction easily proceeds, and as the acrylic-containing group, a 2- (acryloyloxy) ethyloxy group and a 3- (acryloyloxy) propyloxy group are more preferable.
The position of the (meth) acrylic group in the molecule is not limited, but it is preferably provided at the end of the linear organopolysiloxane from the viewpoint of improving the bendability of the cured product.

Examples of the organic group bonded to the silicon atom other than the (meth) acrylic-containing group and the phenyl group in the component (B) include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, a chloromethyl group and a 3-chloro. Substituent or unsubstituted monovalent hydrocarbon groups such as propyl groups and alkyl halides such as 3,3,3-trifluoropropyl groups are exemplified, and methyl groups are particularly preferable.

The viscosity of the component (B) at 25 ° C. is not limited, but is 10 to 1,000,000 mPa. It is preferably in the range of s, especially 100 to 10,000 mPa. It is preferably within the range of s. Viscosity is 10 to 1,000,000 mPa. Within the range of s, the mechanical properties of the obtained cured product are not deteriorated, the solubility with the component (A) is improved, and the cured product obtained by heat-curing the present composition becomes cloudy. Nor does it reduce handleability. The viscosity is measured by a rotational viscometer.

As an example of the method for producing the component (B),
[1] A hydrosilylation reaction of dimethylchlorosilane with an organopolysiloxane having an alkenyl group bonded to a silicon atom is carried out.
[2] It is obtained by reacting the composition obtained in [1] with a (meth) acrylic acid hydroxyalkyl ester such as 2-hydroxyethyl acrylate in the presence of triethylamine.

（式中、ｐは１〜１，０００の正数であり、ｑは１〜１００の正数であり、ｒは２または３である。括弧が付されたシロキサン単位の配列は任意であってよい。） A preferable example of the component (B) is an organopolysiloxane represented by the following formula (3).

(In the formula, p is a positive number from 1 to 1,000, q is a positive number from 1 to 100, and r is 2 or 3. The parenthesized sequence of siloxane units is arbitrary. Good.)

Here, q / (p + q) is preferably 0.25 to 1, more preferably 0.3 to 1.

（式中、括弧が付されたシロキサン単位の配列は任意であってよい。） Specific examples of the component (B) include those represented by the following formulas.

(In the formula, the arrangement of siloxane units in parentheses may be arbitrary.)

The component (B) may be used alone or in combination of two or more.

The blending amount of the component (B) is preferably 1 to 100 parts by mass, more preferably 10 to 80 parts by mass, and further preferably 20 to 60 parts by mass with respect to 100 parts by mass of the component (A).

[Component (C)]
The component (C) is represented by the following average composition formula (2), and has at least two hydrogen atoms (that is, SiH groups) bonded to silicon atoms in one molecule (usually 2 to 200), preferably 2. It is an organohydrogenpolysiloxane containing up to 20 atoms.
R ² _a H _b SiO [ _{(4-ab) / 2} ] (2)
Wherein, R ² is a substituted identical or different, excluding aliphatic unsaturated hydrocarbon group (excluding an epoxy group-substituted and alkoxy substituted) or unsubstituted monovalent hydrocarbon group, a and b are 0 It is a positive number that satisfies .7 ≦ a ≦ 2.7, 0.01 ≦ b ≦ 1.0, and 0.8 ≦ a + b ≦ 3.0. ]

The organohydrogenpolysiloxane of the component (C) acts as a cross-linking agent that crosslinks with the alkenyl group in the component (A) by a hydrosilylation reaction, and in some cases, the composition is diluted to a viscosity suitable for the application. It is a component that can also act as a reactive diluent for adjustment.

The organohydrogenpolysiloxane of the component (C) may have any molecular structure such as a linear, cyclic, branched, or three-dimensional network structure. Further, the Si—H group may be located at either the end of the molecular chain or the non-end of the molecular chain, or may be located at both of them.

The content of SiH groups per unit mass of the component (C) is preferably in the range of 0.001 to 0.02 mol / g, more preferably 0.004 to 0.017 mol / g.

R ² is an unsubstituted or substituted (excluding epoxy group substitution and alkoxy group substitution) monovalent hydrocarbon group excluding the aliphatic unsaturated hydrocarbon group, and is a methyl group, an ethyl group, a propyl group and an isopropyl group. , Alkyl groups such as butyl group, tert-butyl group, hexyl group, saturated hydrocarbon groups such as cycloalkyl groups such as cyclohexyl group, aryl groups such as phenyl group, trill group, xsilyl group and naphthyl group, benzyl group, Examples thereof include an aralkyl group such as a phenylethyl group and a halogen-substituted hydrocarbon group such as a 3,3,3-trifluoropropyl group, preferably an alkyl group having 1 to 12 carbon atoms, particularly an alkyl group having 1 to 8 carbon atoms and 6 to 6 carbon atoms. Twelve aryl groups, particularly preferably methyl or phenyl groups.
Further, it is preferable that the number of phenyl groups is 10 to 60% with respect to the total number of ^{R 2.}

The viscosity of the component (C) at 25 ° C. is preferably 1,000 mPa · s or less, more preferably 3 to 100 mPa · s, from the viewpoint of handleability of the composition and mechanical properties of the cured product. The viscosity is measured by a rotational viscometer.

（式中、Ｒ^２は上記で定義した通りであり、ｅは２〜１００の整数、ｆは２〜１００の整数、ｇは１〜３０の整数である。括弧が付されたシロキサン単位の配列は任意であってよい。） Examples of the component (C) include organohydrogenpolysiloxane represented by the following formula.

(In the formula, R ² is as defined above, e is an integer of 2 to 100, f is an integer of 2 to 100, and g is an integer of 1 to 30. An array of siloxane units in parentheses. May be optional.)

（式中、括弧が付されたシロキサン単位の配列は任意であってよい。）

Specific examples of the component (C) include organohydrogenpolysiloxane represented by the following formula.

(In the formula, the arrangement of siloxane units in parentheses may be arbitrary.)

The component (C) may be used alone or in combination of two or more.

The blending amount of the component (C) is the number of aliphatic unsaturated hydrocarbon groups in the components (A) and (B), that is, the total number of alkenyl groups and (meth) acrylic groups in the component (C). The ratio of the number of SiH groups is 0.01 to 0.5, preferably 0.05 to 0.5, and more preferably 0.2 to 0.4. .. If it is less than 0.01, curing may be insufficient, and if it exceeds 0.5, the bending resistance of the cured product is inferior.

[(D) component]
The hydrosilylation reaction catalyst of the component (D) can be any catalyst known to have an action of accelerating the hydrosilylation reaction, and is typically platinum-based, rhodium-based, or palladium-based. Platinum group metal catalysts can be used. Generally, chloroplatinic acid and its modified products are used. In particular, for electronic applications, a low chlorine catalyst is preferable, and for example, a platinum compound catalyst modified with divinyltetramethyldisiloxane or divinyldiphenyldimethyldisiloxane from which chlorine has been removed is preferable.

The amount of the component (D) added may be an effective amount as a catalyst, but from the viewpoint of curability and suppression of coloration derived from the metal, the total mass of the components (A), (B) and (C) On the other hand, it is generally preferably 100 ppm or less (usually 0.1 to 100 ppm), particularly preferably 50 ppm or less (for example, 0.5 to 50 ppm) based on the mass of the metal contained in the catalyst.

[(E) component]
The addition-curable silicone composition of the present invention may further contain (E) an organic peroxide. This component has the effect of promoting the polymerization of the (meth) acrylic group of the component (B) and increasing the hardness of the cured product. As a result, a cured product having a higher hardness can be provided without impairing the flexibility.

Specific examples of the organic peroxide include diacyl peroxide, peroxy ester, dialkyl peroxide, peroxydicarbonate, peroxyketal, hydroperoxide, silyl peroxide and the like.

Examples of the diacyl peroxide include isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, and dichloromethane. Oxides, benzoyl peroxytoluene and benzoyl peroxide can be mentioned.

Examples of the peroxyester include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, and t. -Hexylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis ( 2-Ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethyl Hexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy-3,5,5-trimethylhexanonate, t-butylperoxylaurate, 2,5 -Dimethyl-2,5-bis (m-toroil peroxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, t-butylper Examples thereof include oxyacetate and bis (t-butylperoxy) hexahydroterephthalate.

Examples of the dialkyl peroxide include α, α'-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane and t. -Butyl humyl peroxide can be mentioned.

Examples of the peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, and di-2-ethoxymethoxyperoxydicarbonate. Examples thereof include bis (2-ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate and bis (3-methyl-3-methoxybutylperoxy) dicarbonate.

Examples of peroxyketal include 1,6-bis (t-butylperoxycarbonyloxy) hexane, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, and 1,1-. Bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 1,1- Included are bis (t-butylperoxy) cyclohexane and 2,2-bis (t-butylperoxy) decane.

Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

Examples of the silyl peroxide include t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide, and tris (t-butyl). Examples thereof include butyl) vinylsilyl peroxide, t-butyltriallylsilyl peroxide, bis (t-butyl) diallylsilyl peroxide and tris (t-butyl) allylsilyl peroxide.

The component (E) may be used alone or in combination of two or more.

The blending amount of the component (E) is preferably in the range of 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the component (B).

[Other ingredients]
In addition to the above components (A) to (E), other components exemplified below may be added to the addition-curable silicone composition of the present invention, if necessary.

Addition reaction control agent:
An addition reaction control agent can be added to the addition-curable silicone composition of the present invention for the purpose of ensuring pot life. The addition reaction control agent is not particularly limited as long as it is a compound having a curing inhibitory effect on the hydrosilylation catalyst of the component (D), and conventionally known compounds can be used. Specific examples of the addition reaction control agent include phosphorus-containing compounds such as triphenylphosphine; nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine and benzotriazole; sulfur-containing compounds; acetylene alcohols (eg, 1-ethynylcyclohexanol, Examples thereof include acetylene compounds such as 3,5-dimethyl-1-hexin-3-ol); hydroperoxy compounds; and maleic acid derivatives.

Adhesive improver:
The adhesiveness improver includes an organopolysiloxane or an organosilane compound having at least one, preferably two or more alkoxy groups bonded to a silicon atom in one molecule, or an organopolysiloxane containing a group having an epoxy moiety. Organosilane compounds are preferred.

Other additives:
Further, depending on the requirement of transparency, an inorganic filler such as fumed silica may be blended in order to improve the hardness, and if necessary, a wavelength adjuster, a dye, a flame retardant, a heat resistant agent, and an oxidation resistance. Degrading agents and the like may be added.

[Silicone cured product]
A silicone cured product (silicone resin cured product) can be obtained by molding and curing the addition-curable silicone composition of the present invention. The molding method is not particularly limited, but press molding using a mold is particularly preferable.
The addition-curable silicone composition of the present invention is cured at room temperature or by heating, but it is preferable to heat it in order to cure it quickly. The curing conditions vary depending on the shape of the molded product, the curing method, etc., and are not particularly limited, but the curing temperature is preferably 80 to 200 ° C., more preferably 100 to 180 ° C., and the curing time is preferably 1 minute to 24 hours. More preferably, it is 5 minutes to 5 hours.

Further, the hardness of the cured silicone product of the present invention is preferably 25 or more for the durometer type D. Such a cured silicone product has sufficient hardness in applications requiring bending resistance, such as optical components such as flexible substrates or surface materials for flexible panels.

[Sheet]
By molding the cured silicone product of the present invention into a sheet, a sheet having good bending resistance can be obtained. The bending resistance of the sheet of the present invention is preferably such that the radius of curvature at which cracks occur when bent at a thickness of 0.2 mm is less than 1.5 mm.

The sheet has sufficient hardness and excellent bending resistance. Therefore, even if the sheet thinly processed with the silicone resin alone is bent, it will not be easily cracked.

[Optical parts]
The silicone cured product or the sheet can be applied to optical components.
The cured silicone product of the present invention or the sheet is useful as a surface material for optical components, particularly flexible substrates or flexible panels, because it has sufficient hardness and excellent bending resistance.
As described above, the optical component of the present invention has sufficient hardness and excellent bending resistance, and is therefore suitable for applications requiring flexibility.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
The compounds of each component used in the examples are as follows.

(A) Ingredient:
A solid organopolysiloxane having an average structure represented by the following formula (1'), obtained by co-hydrolysis of phenyltrichlorosilane, diphenyldichlorosilane, and methylvinyldichlorosilane and dehydration condensation using potassium hydroxide.
[(CH ₃ ) (CH ₂ = CH) SiO] _6.2 [(C ₆ H ₅ ) ₂ SiO] _2.5 [(C ₆ H ₅ ) SiO _3/2 ] ₇ (1')

（式中、括弧が付されたシロキサン単位の配列は不定である。） (B) Ingredient:
Organosiloxane having an average structure represented by the following formula

(In the formula, the sequence of siloxane units in parentheses is indefinite.)

（式中、括弧が付されたシロキサン単位の配列は不定である。）
（Ｃ−２）下記式で表される平均構造を有するオルガノハイドロジェンポリシロキサン

Ingredient (C):
(C-1) Organohydrogenpolysiloxane having an average structure represented by the following formula

(In the formula, the sequence of siloxane units in parentheses is indefinite.)
(C-2) Organohydrogenpolysiloxane having an average structure represented by the following formula

Ingredient (D):
Chloroplatinic acid dimethyldiphenyl silicone oil solution (platinum content: 1% by mass)

(E) Ingredient:
1,6-bis (t-butylperoxycarbonyloxy) hexane (Kayaren 6-70, manufactured by Kayaku Akzo Corporation)

[Examples 1 to 4 and Comparative Examples 1 to 3]
The above components (A) to (E) were mixed in the blending amounts (parts by mass) shown in Table 1 to prepare an addition-curable silicone composition. The value of [Si—H] / [aliphatic unsaturated hydrocarbon group] (hereinafter, also referred to as “SiH ratio”) is the value of the aliphatic unsaturated hydrocarbon group in the component (A) and the component (B). It was calculated as the ratio of the number of SiH groups in the component (C) to the total number of alkenyl groups and (meth) acrylic groups.

<Manufacturing and evaluation of cured sheet>
The addition-curable silicone compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were heat-cured at 150 ° C. for 1 hour using a mold to obtain colorless and transparent sheets having a thickness of 2 mm and 0.2 mm. Manufactured. The obtained sheet was evaluated as follows, and the results are shown in Table 2.

[hardness]
The hardness of the test piece obtained by stacking three sheets having a thickness of 2 mm was measured using a type D durometer in accordance with JIS K 6253-: 2012.

[Bending test]
The state when a 30 mm × 70 mm sheet was bent along a mandrel having a diameter of 3 mm so as to align the sides of 30 mm (radius of curvature 1.5 mm) was evaluated as 〇 (bend without cracking) and × (break). If it bends without cracking, the radius of curvature at which the crack occurs is less than 1.5 mm. Evaluation was performed on a 2 mm thick sheet and a 0.2 mm thick sheet.

From Tables 1 and 2, the cured product obtained by curing the addition-curable silicone composition of Examples 1 to 4 has a higher SiH ratio than that of the present invention, Comparative Example 1 and Comparative Example 2 which does not contain the component (B). It can be seen that it is superior in bending resistance to the cured product of No. 3 and can be applied to a flexible base material.
Furthermore, the addition-curable silicone compositions of Examples 3 and 4 containing organic peroxides did not impair flexibility, resulting in a harder cured product.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. Is included in the technical scope of.

Claims (8)

(A) Organopolysiloxane represented by the following average composition formula (1),
R ¹ _n (C ₆ H ₅ ) _m SiO _{(4-n-m) / 2} (1)
[In the formula, R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group (excluding the unsubstituted phenyl group), alkoxy group or hydroxyl group, and 0.1 to 80 mol% ^{of the total R 1.} Is an alkenyl group, and n and m are 0.1 ≦ n <0.8, 0.2 ≦ m <1.9, 1 ≦ n + m <2, and 0.20 ≦ m / (n + m) ≦ 0. It is a positive number that satisfies 95. ]
(B) A linear organopolysiloxane having at least two (meth) acrylic groups and a phenyl group bonded to at least one silicon atom in one molecule.
(C) Organohydrogenpolysiloxane represented by the following average composition formula (2) and containing at least two hydrogen atoms bonded to a silicon atom in one molecule: an aliphatic substance in the components (A) and (B). An amount in which the ratio of the number of hydrogen atoms bonded to silicon atoms in the component (C) to the number of unsaturated hydrocarbon groups is 0.01 to 0.5.
R ² _a H _b SiO _{(4-ab) / 2} (2)
Wherein, R ² is a substituted identical or different, excluding aliphatic unsaturated hydrocarbon group (excluding an epoxy group-substituted and alkoxy substituted) or unsubstituted monovalent hydrocarbon group, a and b are 0 It is a positive number that satisfies .7 ≦ a ≦ 2.7, 0.01 ≦ b ≦ 1.0, and 0.8 ≦ a + b ≦ 3.0. ]
as well as,
(D) Hydrosilylation reaction catalyst,
An addition-curable silicone composition comprising. The addition-curable silicone composition according to claim 1, wherein the component (B) is a linear organopolysiloxane represented by the following formula (3).

(In the formula, p is a positive number from 1 to 1,000, q is a positive number from 1 to 100, and r is 2 or 3. The parenthesized sequence of siloxane units is arbitrary. Good.) The addition-curable silicone composition according to claim 2, wherein q / (p + q) in the formula (3) is 0.25 to 1. The addition-curable silicone composition according to any one of claims 1 to 3, further comprising (E) an organic peroxide. A silicone cured product, which is a cured product of the addition-curable silicone composition according to any one of claims 1 to 4. A sheet comprising the cured silicone product according to claim 5. The sheet according to claim 6, wherein the radius of curvature at which cracks occur when bent at a thickness of 0.2 mm is less than 1.5 mm. An optical component having the cured silicone product according to claim 5 or the sheet according to claim 6 or 7.