JP2022089761A - Curable silicone composition - Google Patents

Abstract

To provide a curable silicone composition which exhibits good curability and has a sufficient pot life at normal temperature.SOLUTION: The curable silicone composition comprises at least (A) an organopolysiloxane having at least two alkenyl groups in one molecule, (B) an organopolysiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule, (C) a catalyst for hydrosilylation reaction, and (D) a glycoluril compound represented by the general formula (where each R1 is independently a C1-6 alkyl group or a C3-6 alkenyl group, provided that at least one R1 is the alkenyl group; and each R2 is independently a hydrogen atom or a C1-6 alkyl group).SELECTED DRAWING: None

Description

The present invention relates to a curable silicone composition.

A curable silicone composition that cures by an addition reaction in the presence of a catalyst for a hydrosilylation reaction is widely used because it cures rapidly by heating to form a cured silicone product having excellent heat resistance and weather resistance. .. However, such a curable silicone composition has a problem that the pot life at room temperature is remarkably shortened when trying to promote the curability.

Therefore, Patent Document 1 proposes to control the curing start time and the curing time of the curable silicone composition by blending a triazole-based compound, and Patent Document 2 describes a derivative of acetylene alcohol. It has been proposed to extend the pot life of the curable silicone composition by blending the above, but none of them has achieved both curability and pot life.

On the other hand, in Patent Document 3, a glycoluril compound is blended with a curable silicone composition containing a catalyst for a hydrosilylation reaction to form a cured product having excellent transparency, heat resistance, sulfide resistance and adhesion. Has been proposed. However, in Patent Document 3, in order to achieve the above object, 0.1 to 50 glycoluril compounds are added to a total of 100 parts by mass of the alkenyl group-containing organopolysiloxane and the silicon atom-bonded hydrogen atom-containing organopolysiloxane. Although it is described that the mixture is blended in parts by mass, in the embodiment, 1 to 50 parts by mass is also blended, and it is no longer possible to achieve both curability and pot life with such a composition.

Japanese Unexamined Patent Publication No. 2014-122271 Special Table 2019-504919 Japanese Unexamined Patent Publication No. 2015-129274

An object of the present invention is to provide a curable silicone composition having good curability and having a sufficient pot life at room temperature.

（式中、各Ｒ^１は独立に、炭素数１～６のアルキル基、または炭素数３～６のアルケニル基であり、但し、少なくとも一つのＲ^１は前記アルケニル基であり、各Ｒ^２は独立に、水素原子、または炭素数１～６のアルキル基である。）
で表されるグリコールウリル化合物 ０.００１～０.３質量部
から少なくともなることを特徴とする。 The curable silicone composition of the present invention is
(A) 100 parts by mass of an organopolysiloxane having at least two alkenyl groups in one molecule,
(B) Organopolysiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule (A) For a total of 1 mol of alkenyl groups in the component, the silicon atom-bonded hydrogen atom in this component is 0.1 to 0.1 to Amount of 10 mol,
(C) Catalyst for hydrosilylation reaction of catalytic amount, and (D) general formula:

(In the formula, each R ¹ is independently an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 3 to 6 carbon atoms, except that at least one R ¹ is the alkenyl group and each R ² is an alkenyl group. Independently, it is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
It is characterized in that it is composed of at least 0.001 to 0.3 parts by mass of the glycoluril compound represented by.

In this composition, the component (B) contains the formula: HR ₂ SiO _1/2 (in the formula, each R independently has an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and 7 carbon atoms. It is preferably an organopolysiloxane having a siloxane unit represented by (12) an aralkyl group or a fluoroalkyl group having 3 to 12 carbon atoms. The component (B) is a siloxane unit represented by the formula: HR ₂ SiO _1/2 (in the formula, each R is independently the same group as described above), and the formula: SiO _4/2 . An organopolysiloxane having a siloxane unit to be formed, or a siloxane unit represented by the formula: HR ₂ SiO _1/2 , and a formula: RSiO _3/2 (in the formula, each R is independently the same group as described above. It is preferably an organopolysiloxane having a siloxane unit represented by.).

で表されるグリコールウリル化合物であることが好ましい。 In this composition, the component (D) is represented by the formula:

It is preferably a glycoluril compound represented by.

It is preferable that the present composition further has (E) a hydrosilylation reaction inhibitor other than the component (D).

The curable silicone composition of the present invention is characterized by having good curability and having a sufficient pot life at room temperature.

<Curable silicone composition>
The component (A) is the main agent of the present composition and is an organopolysiloxane having at least two alkenyl groups in one molecule. Examples of the alkenyl group in the component (A) include an alkenyl group having 2 to 12 carbon atoms such as a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group and a decenyl group. It is preferably a vinyl group or a hexenyl group. Examples of the group bonded to the silicon atom other than the alkenyl group in the component (A) include an alkyl having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and a heptyl group. Group; aryl group having 6 to 12 carbon atoms such as phenyl group, trill group and xylyl group; aralkyl group having 7 to 12 carbon atoms such as benzyl group and phenethyl group; 3,3,3-trifluoropropyl group, 4, 4,4,3,3-pentafluorobutyl group, 5,5,5,4,4,3,3-heptafluoropentyl group, 6,6,6,5,5,4,4,3,3 -A fluoroalkyl group having 3 to 12 carbon atoms such as a nonafluorohexyl group, a 7,7,7,6,6,5,5,4,4,3,3-undecafluoroheptyl group is exemplified and preferably. , Methyl group, phenyl group, 3,3,3-trifluoropropyl group. In order to improve the oil resistance and cold resistance of the cured silicone product obtained by curing the present composition, the component (A) preferably has a fluoroalkyl group. In that case, the proportion of the fluoroalkyl group in the component (A) is not limited, but is preferably 5 mol% or more, 10 mol% or more, or 20 mol% or more, while 70. It is mol% or less, or 60 mol% or less, and is within an arbitrary range between the lower limit and the upper limit. Furthermore, a small amount of hydroxyl group or an alkoxy group such as a methoxy group or an ethoxy group may be bonded to the silicon atom in the component (A) as long as the object of the present invention is not impaired.

The molecular structure of the component (A) is not limited, and examples thereof include a linear chain, a branched chain, a linear chain having a partial branch, and a resin. The viscosity of the component (A) at 25 ° C. is not limited, but is preferably liquid to raw rubber having a viscosity of at least 100 mPa · s at 25 ° C. When the component (A) is liquid, its viscosity at 25 ° C. is preferably in the range of 100 to 100,000 mPa · s, or in the range of 500 to 50,000 mPa · s. This is because when the viscosity of the component (A) is not less than the lower limit of the above range, the mechanical strength of the obtained cured silicone product is improved, while when it is not more than the upper limit of the above range, the present composition This is because the handling workability and filling property are improved. The viscosity of the component (A) at 25 ° C. can be measured by a rotational viscometer conforming to JIS K7117-1. On the other hand, when the component (A) is in the form of raw rubber, the Williams plasticity at 25 ° C. specified in JIS K 6249 is preferably in the range of 100 to 800, or in the range of 100 to 400.

Examples of such the component (A) include a dimethylpolysiloxane having a dimethylvinylsiloxy group-blocking at both ends of the molecular chain, a dimethylvinylsiloxy group-blocking dimethylsiloxane / methylvinylsiloxane copolymer having both ends of the molecular chain, and a dimethylvinyl having both ends of the molecular chain. Syroxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer, molecular chain double-ended trimethylsiloxy group-blocked methylvinylpolysiloxane, molecular chain double-ended trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, molecular chain double-ended silanol group Blocked dimethylsiloxane / methylvinylsiloxane copolymer, molecular chain double-ended dimethylvinylsiloxy group closed dimethylsiloxane / methyl (3,3,3-trifluoropropyl) siloxane copolymer, molecular chain double-ended dimethylvinylsiloxy group closed dimethyl Siloxane / Methylvinylsiloxane / Methyl (3,3,3-trifluoropropyl) siloxane copolymer, dimethylvinylsiloxy group-blocked at both ends of the molecular chain dimethylsiloxane / methylphenylsiloxane / methyl (3,3,3-trifluoropropyl) ) Siloxane copolymers, trimethylsiloxy group-blocking methyl (3,3,3-trifluoropropyl) siloxane / methylvinylsiloxane copolymers at both ends of the molecular chain, and mixtures of two or more of these can be mentioned.

The component (B) is a cross-linking agent of the present composition, and is an organopolysiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule. Examples of the group bonded to the silicon atom other than the hydrogen atom in the component (B) include an alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and a heptyl group; Aryl groups having 6 to 12 carbon atoms such as phenyl group, trill group and xylyl group; aralkyl groups having 7 to 12 carbon atoms such as benzyl group and phenethyl group; 3,3,3-trifluoropropyl group, 4,4, 4,3,3-pentafluorobutyl group, 5,5,5,4,4,3,3-heptafluoropentyl group, 6,6,6,5,5,4,4,3,3-nona Fluoroalkyl groups having 3 to 12 carbon atoms such as a fluorohexyl group, 7,7,7,6,6,5,5,4,4,3,3-undecafluoroheptyl group are exemplified and preferably methyl. Group, phenyl group, 3,3,3-trifluoropropyl group. When the component (A) has a fluoroalkyl group, the component (B) preferably also has a fluoroalkyl group in order to improve the oil resistance and cold resistance of the cured silicone obtained by curing the present composition. .. In that case, the proportion of the fluoroalkyl group in the component (B) is not limited, but is preferably 5 mol% or more, 10 mol% or more, or 15 mol% or more, while 70. It is mol% or less, 60 mol% or less, 50 mol% or less, or 40 mol% or less, and is within an arbitrary range of the lower limit and the upper limit. Furthermore, a small amount of hydroxyl group or an alkoxy group such as a methoxy group or an ethoxy group may be bonded to the silicon atom in the component (B) as long as the object of the present invention is not impaired.

The molecular structure of the component (B) is not limited, and examples thereof include a linear chain, a branched chain, a linear chain having a partial branch, a cyclic, and a resin. Further, the viscosity of the component (B) is not limited, but preferably the kinematic viscosity at 25 ° C. is in the range of 1 to 10,000 mm ² / s or in the range of 1 to 2,000 mm ² / s. .. This is because when the viscosity of the component (B) is not less than the lower limit of the above range, the mechanical strength of the obtained cured silicone product is improved, while when it is not more than the upper limit of the above range, the present composition This is because the handling workability and filling property are improved. The viscosity of the component (B) can be measured by a viscometer based on JIS K2283: 2000 "Crude oil and petroleum products-kinematic viscosity test method and viscosity index calculation method".

Examples of such the component (B) include a trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both ends of the molecular chain, a trimethylsiloxy-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both ends of the molecular chain, and a dimethylhydrogensiloxy at both ends. Group-blocked dimethylpolysiloxane, molecular chain double-ended trimethylsiloxy group-blocked methylhydrogensiloxane / methyl (3,3,3-trifluoropropyl) siloxane copolymer, molecular chain double-ended trimethylsiloxy-blocked dimethylsiloxane / methylhydrogensiloxane -Methyl (3,3,3-trifluoropropyl) siloxane copolymer, double-ended dimethylhydrogensiloxy group-blocking methyl (3,3,3-trifluoropropyl) polysiloxane, molecular chain double-ended dimethylhydrogensiloxy group Closing methyl (3,3,3-trifluoropropyl) polysiloxane, dimethylhydrogensiloxy group-blocking dimethylsiloxane / methylhydrogensiloxane / methyl (3,3,3-trifluoropropyl) siloxane copolymer at both ends of the molecular chain , And mixtures of two or more of these.

In general, when an organopolysiloxane having a siloxane unit represented by the formula: HR ₂ SiO _1/2 is used as the component (B), the pot life of the curable silicone composition tends to be shortened. In this composition, when the component (B) is an organopolysiloxane having a siloxane unit represented by the formula: HR ₂ SiO _1/2 , the effect of extending the pot life by blending the component (D) is particularly effective. It becomes remarkable. In the formula, R is independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a fluoroalkyl group having 3 to 12 carbon atoms. The same groups as described above are exemplified.

Such a component (B) has a siloxane unit represented by the formula: HR ₂ SiO _1/2 and a siloxane unit represented by the formula: SiO _4/2 , and optionally has the formula: R ₂ SiO. Organopolysiloxane which may contain a siloxane unit represented by _2/2 and a siloxane unit represented by the formula: RSiO _3/2 , a siloxane unit represented by the formula: HR ₂ SiO _1/2 , and a formula: RSiO ₃ An organopolysiloxane having a siloxane unit represented by _{/ 2} , and optionally containing a siloxane unit represented by the formula: R ₂ SiO _2/2 or a siloxane unit represented by the formula: SiO _4/2 , Alternatively, it has a siloxane unit represented by the formula: HR ₂ SiO _1/2 and a siloxane unit represented by the formula: R ₂ SiO _2/2 , and optionally has a siloxane represented by the formula: SiO _4/2 . Units and formulas: Organopolysiloxanes that may contain siloxane units represented by RSiO _3/2 are exemplified, and specifically, the average unit formula:
[HR ₂ SiO _1/2 ] _a (SiO _4/2 ) ₁
Organopolysiloxane represented by, average unit formula:
[HR ₂ SiO _1/2 ] _b (RSiO _3/2 ) ₁
Organopolysiloxane represented by, general formula:
HR ₂ SiO (R ₂ SiO) _m SiR ₂ H
Organopolysiloxane represented by, or general formula:
HR ₂ SiO (R ₂ SiO) _m (HRSiO) _n SiR ₂ H
Organopolysiloxane represented by is exemplified.

In the above equation, R is the same as described above. Further, a is a number satisfying 0 <a ≦ 4, preferably 0.5 ≦ a ≦ 1.8. Further, b is a number satisfying 0 <b ≦ 3, preferably 0.5 ≦ b ≦ 1.8. Further, m and n are positive numbers in which the kinematic viscosity of the component (B) at 25 ° C. is in the range of 1 to 10,000 mm ² / s or in the range of 1 to 2,000 mm ² / s.

The content of the component (B) is in the range of 0.1 to 10 mol of the silicon atom-bonded hydrogen atom in this component with respect to the total of 1 mol of the alkenyl group in the component (A). Preferably, the amount is in the range of 0.5 to 10 mol, the amount is in the range of 0.8 to 5 mol, and the amount is in the range of 1.1 to 5 mol. This is because the composition is sufficiently cured when the content of the component (B) is not less than the lower limit of the above range, while the heat resistance of the obtained silicone cured product is not more than the upper limit of the above range. This is because the property becomes good.

The component (C) is a catalyst for a hydrosilylation reaction for accelerating the curing of the present composition. Examples of the component (C) include a platinum-based catalyst, a palladium-based catalyst, and a rhodium-based catalyst, and a platinum-based catalyst is preferable. The platinum-based catalyst includes platinum chloride acid, platinum chloride hexahydrate, platinum dichloride, alcohol solution of platinum chloride acid, platinum olefin complex, platinum carbonyl complex, platinum alkenylsiloxane complex, and platinum diketone complex. , A non-microcapsule type hydrosilylation reaction catalyst such as a platinum olefin complex, and a micro of a resin having a softening point of 40 to 170 ° C. such as an acrylic resin, a polycarbonate resin, a silicone resin, etc., which disperses or contains these platinum-based catalysts. An example is a catalyst for a capsule hydrosilylation reaction. In the platinum alkenylsiloxane complex, examples of the alkenylsiloxane include 1,3-divinyltetramethyldisiloxane, 1,1,3,3-tetravinyldimethyldisiloxane, and dimethylvinylsiloxy group-blocking methyl (3,3). , 3-Trifluoropropyl) siloxane oligomer.

The content of the component (C) is a catalytic amount that promotes the curing of the present composition, and specifically, the catalytic metal in the present component with respect to the present composition is in the range of 0.1 to 1,000 ppm in mass units. The amount is in the range of 0.1 to 500 ppm, or the amount is in the range of 0.1 to 250 ppm. This is because when the content of the component (C) is not less than the lower limit of the above range, the curing of the present composition is sufficiently promoted, while when it is not more than the upper limit of the above range, the obtained silicone is obtained. This is because the cured product is less likely to cause problems such as coloring.

で表される。 The component (D) is a glycoluril compound for adjusting the curability of the present composition, and has a general formula:

It is represented by.

In the formula, each R ¹ is independently an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 3 to 6 carbon atoms. Examples of the alkyl of R ¹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Examples of the alkenyl group of R ¹ include an allyl group, a butenyl group, a pentenyl group, and a hexenyl group. In the above formula, at least one R ¹ is the alkenyl group, preferably an allyl group.

Further, in the above formula, each R ² is independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. As the alkyl group of ^R2 , the same group as the alkyl of R1 is exemplified.

Examples of such component (D) include glycoluril compounds represented by the following formulas.

In the present composition, the content of the component (D) is in the range of 0.001 to 0.3 parts by mass with respect to 100 parts by mass of the component (A), and is preferably 0.001 to 0. It is within the range of 2 parts by mass. When a microcapsule type hydrosilylation reaction catalyst is used as the component (C), it is preferably in the range of 0.001 to 0.3 parts by mass, or 0.001 to 0.2 parts by mass. On the other hand, when a non-microcapsule type hydrosilylation reaction catalyst is used, it is preferably in the range of 0.001 to 0.3 parts by mass, and 0.001 to 0.2 parts by mass. Or within the range of 0.001 to 0.15 parts by mass. This is because if the content of the component (D) is not less than the lower limit of the above range, the pot life of the present composition at room temperature is sufficient, while if it is not more than the upper limit of the above range, the present composition is sufficient. This is because the curability of the composition is good, and the compression set ratio of the obtained cured silicone product can be reduced.

In addition, the composition may contain (E) a hydrosilylation reaction inhibitor other than the component (D) in order to control the curing rate of the composition together with the component (D). The component (E) includes 2-methyl-3-butyne-2-ol, 3,5-dimethyl-1-hexin-3-ol, 3-methyl-1-pentin-3-ol, and 2-phenyl-. Alkyne alcohols such as 3-butyne-2-ol, 1-ethynyl-1-cyclohexanol, 2-ethynylisopropanol, 2-ethynylbutane-2-ol; trimethyl (3,5-dimethyl-1-hexin-3-oxy) ) Silane, dimethylbis (3-methyl-1-butynoxy) silane, methylvinylbis (3-methyl-1-butyne-3-oxy) silane, and [(1,1-dimethyl-2-propynyl) oxy] trimethyl Cyrilized acetylene alcohols such as silane; 2-isobutyl-1-butene-3-in, 3,5-dimethyl-3-hexene-1-in, 3-methyl-3-pentene-1-in, 3-methyl- 3-Hexen-1-in, 1-ethynylcyclohexene, 3-ethyl-3-butene-1-in, 3-phenyl-3-butene-1-in and other enein compounds; diallyl maleate, dimethyl maleate, etc. Diethyl fumarate, diallyl fumarate, bis-2-methoxy-1-methylethyl maleate, monooctyl maleate, monoisooctyl maleate, monoallyl maleate, monomethyl maleate, monoethyl fumarate, monoallyl fumarate. , And unsaturated carboxylic acid esters such as 2-methoxy-1-methylethylmaleate; 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane 1,3,5 , 7-Tetramethyl-1,3,5,7-Alkyne siloxane such as tetrahexenylcyclotetrasiloxane; Other examples thereof include benzotriazole.

The content of the component (E) is not limited, but is preferably 5 parts by mass or less, or 3 parts by mass or less, based on 100 parts by mass of the total of the components (A) and (B). The lower limit is 0.01 part by mass or more, or 0.1 part by mass or more. The content of the component (E) can be in any range in which the upper limit and the lower limit are combined.

The composition may contain silica fine powder in order to improve the mechanical properties of the silicone cured product obtained by curing the composition. Examples of the silica fine powder include dry silica such as fumed silica and wet silica such as precipitated silica, and their surfaces are organosilane, hexaorganodisilazane, diorganopolysiloxane, and diorganocyclopoly. Fine powdered silica that has been hydrophobized with an organosilicon compound such as siloxane can also be used. The BET specific surface area of this silica fine powder is not limited, but is preferably in the range of 50 m ² / g to 500 m ² / g, or in the range of 100 to 500 m ² / g.

The content of the silica fine powder is not limited, but it is preferably 5 parts by mass or more with respect to 100 parts by mass of the component (A) because the mechanical properties of the obtained cured silicone product are good. Since the formability of the present composition is good, it is preferably 200 parts by mass or less with respect to 100 parts by mass of the component (A).

In addition, various compounding agents usually used for curable silicone compositions may be added to the present composition to the extent that the object of the present invention is not impaired. Examples of this compounding agent include silanol soil, quartz powder, calcium carbonate and other bulking fillers; thermal conductivity improvers such as alumina, zinc oxide and boron nitride; flame retardant improvers such as magnesium hydroxide and aluminum hydroxide. Carbon black such as acetylene black, furnace black, channel black; pigments such as titanium oxide and petals; heat resistance improver such as rare earth oxides, cerium silanolate, cerium fatty acid salt; stearic acid, zinc stearate, calcium stearate Mold release agents such as fatty acids and their metal salts; dispersants such as alkoxysilanes, diphenylsilanediols, carbon functional silanes, silanol-based blocking diorganosiloxane oligomers at both ends of the molecular chain; vinyltrimethoxysilanes, allyls Trimethoxysilane, allyltriethoxysilane, hydrogenentriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3 -Alkoxysilanes such as methaloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; dimethylsiloxane / methylvinylsiloxane copolymer oligomer having a silanol group block at both ends of the molecular chain, and methylvinyl having a silanol group block at both ends of the molecular chain. Contains alkenyl group-containing diorganosiloxane oligomers that block silanol groups at both ends of the molecular chain, such as siloxane oligomers, and epoxy groups such as 3-glycidoxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Reaction mixture with alkoxysilane; reaction mixture of alkenyl group-containing diorganosiloxane oligomer with silanol groups at both ends of the molecular chain and 3-methacryloxypropyltrimethoxysilane; epoxy group-containing alkoxysilane and 3-aminopropyl Reaction mixtures of triethoxysilane; other examples include adhesion enhancers such as tris (3-trimethoxysilylpropyl) isocyanurate.

The method for curing the composition is not limited, and mold molding, compression molding, transfer molding, injection molding, extrusion molding, calendar molding and the like can be used. Further, the curing method is not limited, and a well-known curing method such as steam vulcanization or hot air vulcanization can be selected.

The curable silicone composition of the present invention will be described in detail with reference to Examples. The present invention is not limited to these examples. Further, in the examples, the characteristics such as viscosity and plasticity are values at room temperature (25 ° C.) unless otherwise specified. The viscosity (Pa · s) is a value measured using a rotational viscometer compliant with JIS K7117-1, and the kinematic viscosity (mm ² / s) is a value measured using a Uberode type viscometer compliant with JIS Z8803. These are the measured values, and the curability, pot life (change in viscosity) of the curable silicone composition, and the physical properties of the obtained cured silicone composition were measured as follows.

<Curable>
The following vulcanization characteristics of the curable silicone composition were measured using a curastometer type III (manufactured by JSR) according to JIS K6300 under the conditions of 130 ° C./3 minutes.
T10: Time from the initial stage of heating (= vulcanization start point) required for vulcanization to proceed 10% (that is, until the torque reaches 10% of the maximum torque value MH in the vulcanization curve).
T90: Time from the initial heating period (= optimum vulcanization point) required for vulcanization to proceed 90% (that is, until the torque reaches 10% of the maximum torque value MH in the vulcanization curve).

<Pot life (change in viscosity)>
The initial viscosity (Pa · s) immediately after preparation of the curable silicone composition at 25 ° C. and the viscosity (Pa · s) after allowing it to stand at 25 ° C. for a predetermined time are specified in JIS K7117-2: 1999, respectively. It was measured with a rotary leometer (viscoelasticity measuring device AR500 manufactured by TA Instruments) according to the above method. In this measurement, a cone plate having a diameter of 20 mm and a diameter of 2 ° was used, and the share rate was set to 10.0 (S ^-1 ).

<Hardness>
According to the test method using the type A hardness tester specified in JIS K6253, three test pieces having a thickness of 2 mm were stacked and used.

<Compression permanent distortion rate>
The compression set after 22 hours was measured under the conditions of 180 ° C. and 25% compression according to the method specified in JIS K6262.

<Example 1-14, Comparative Example 1-6>
The following components were uniformly mixed so as to have the composition shown in Table 1-3 to prepare a curable silicone composition. Note that SiH / Vi in the table indicates the number of moles of silicon atom-bonded hydrogen atom in the component (B) with respect to a total of 1 mol of the alkenyl group in the component (A).

The following components were used as the component (A).
(A-1): Molecular chain with a viscosity of 10,000 mPa · s Both ends dimethylvinylsiloxy group-sealed dimethylpolysiloxane (vinyl group content = about 0.13% by mass)
(A-2): Molecular chain with a viscosity of 40,000 mPa · s Both ends dimethylvinylsiloxy group-sealed dimethylpolysiloxane (vinyl group content = about 0.09% by mass)
(A-3): Molecular chain double-ended trimethylsiloxy group-sealed dimethylsiloxane / methylvinylsiloxane copolymer having a viscosity of 40,000 mPa · s (vinyl group content = about 0.13% by mass)

The following components were used as the component (B).
(B-1): Average unit formula of kinematic viscosity 25 mm ² / s:
[H (CH ₃ ) ₂ SiO _1/2 ] _1.6 (SiO _4/2 ) ₁
Organopolysiloxane represented by (content of silicon atom-bonded hydrogen atom = about 0.97% by mass)
(B-2): A kinematic viscosity of 10 mm ² / s, a siloxane unit represented by the formula: H (CH ₃ ) ₂ SiO _1/2 , a siloxane unit represented by the formula: (CH ₃ ) ₂ SiO _2/2 . , And formula: H (CH ₃ ) SiO _2/2 molecular chain consisting of siloxane units Both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer (content of silicon atom-bonded hydrogen atom) = Approximately 0.39% by mass)
(B-3): kinematic viscosity 5 mm ² / s, formula: (CH ₃ ) ₃ siloxane unit represented by SiO _1/2 , formula: (CH ₃ ) ₂ siloxane unit represented by SiO _2/2 , And formula: H (CH ₃ ) SiO _2/2 molecular chain consisting of siloxane units Both ends trimethylsiloxy group-sealed dimethylsiloxane / methylhydrogensiloxane copolymer (content of silicon atom-bonded hydrogen atom = about 0) .77% by mass)
(B-4): Siloxane unit represented by the formula: H (CH ₃ ) ₂ SiO _1/2 with a kinematic viscosity of 10 mm ² / s, and the siloxane represented by the formula: (CH ₃ ) ₂ SiO _2/2 . Molecular chain consisting of units Dimethylhydrogensiloxy group-sealed dimethylpolysiloxane (content of silicon atom-bonded hydrogen atom = about 0.16% by mass)
(B-5): kinematic viscosity of 15 mm ² / s, formula: (CH ₃ ) ₃ siloxane unit represented by SiO _1/2 , formula: (CH ₃ ) ₂ siloxane unit represented by SiO _2/2 , Formula: A branched chain in which the end of the molecular chain consisting of a siloxane unit represented by H (CH ₃ ) SiO _2/2 and a siloxane unit represented by the formula: CH ₃ SiO _3/2 is sealed with a trimethylsiloxy group. Dimethylsiloxane / Methylhydrogensiloxane copolymer (content of silicon atom-bonded hydrogen atom = approx. 0.83% by mass)

The following components were used as the component (C).
(C-1): 1,3-Divinyltetramethyldisiloxane solution of 1,3-divinyltetramethyldisiloxane complex of platinum (platinum metal content = about 6,700 ppm)

で表されるグリコールウリル化合物（四国化成工業株式会社製の商品名ＴＡ－Ｇ） The following components were used as the component (D).
(D-1): Equation:

Glycol uryl compound represented by (trade name TA-G manufactured by Shikoku Chemicals Corporation)

Further, as a comparison of the component (D), the following components were used.
(D-2): N, N'-diallyl cyanuric acid compound (trade name LDAIC manufactured by Shikoku Chemicals Corporation)
(D-3): Triallyl isocyanurate (d-4): Bis (N, N'-diallyl cyanuric acid) compound (trade name DD-1 manufactured by Shikoku Chemicals Corporation)

Moreover, the following components were used as the component (E).
(E-1): 1-ethynyl-cyclohexane-1-ol 2 parts by mass and a molecular chain having a viscosity of 10,000 mPa · s Both ends dimethylvinylsiloxy group-sealed dimethylpolysiloxane (vinyl group content = about 0.13 mass) %) 98 parts by mass of the mixture

Moreover, the following component was used as the component (F).
(F-1): Fumeed silica having a BET specific surface area of 255 m ² / g

The above component (f-1) was blended as a silica masterbatch prepared as follows, but each component is described separately in Table 1-3.

<Preparation of silica masterbatch>
100 parts by mass of the above (a-2) component, 40 parts by mass of the above (f-1) component, 7 parts by mass of hexamethyldisilazane, 1.7 parts by mass of water, and dimethylhydroxysiloxy groups at both ends of the molecular chain having a viscosity of 20 mPa · s. Sealed dimethylsiloxane / methylvinylsiloxane copolymer (vinyl group content = about 10.9% by mass) 0.2 parts by mass was put into a loss mixer, mixed until uniform at room temperature, and then reduced to 200 ° C. A fluid silica master batch was prepared by heat treatment with.

<Examples 15-18, Comparative Example 7>
In addition to the above components, the following components were uniformly mixed to prepare a curable silicone composition so as to have the composition shown in Table 4. Note that SiH / Vi in the table indicates the number of moles of silicon atom-bonded hydrogen atom in the component (B) with respect to a total of 1 mol of the alkenyl group in the component (A).

The following components were used as the component (A).
(A-4): Methyl (3,3,3-trifluoropropyl) polysiloxane at both ends of the molecular chain having a viscosity of 50,000 mPa · s (vinyl group content = about 0.15% by mass)

The following components were used as the component (B).
(B-4): kinematic viscosity 7 mm ² / s, average unit formula:
[H (CH ₃ ) ₂ SiO _1/2 ] _1.5 (CF ₃ C ₂ H ₄ SiO _3/2 ) ₁
Branched-chain organopolysiloxane represented by (content of silicon atom-bonded hydrogen atom = about 0.60% by mass)

The following components were used as the component (C).
(C-2): A capsule-type catalyst having a glass transition point of about 65 ° C. in which a 1,3-divinyltetramethyldisiloxane solution of platinum 1,3-divinyltetramethyldisiloxane complex is microencapsulated with a silicone resin. Molecular chain with a viscosity of 2,200 mPa · s containing 40% by mass Vinyl dimethylsiloxy group-sealed dimethylpolysiloxane dispersion (platinum metal content = about 4,000 ppm)

Moreover, the following components were used as the component (E).
(E-2): 2-Methyl-3-butyne-2-ol

Moreover, the above-mentioned (f-1) component and (f-2) component were used as the (F) component.
In Examples 15-18 and Comparative Example 7, the component (f-1) was blended as a silica masterbatch prepared in the same manner as described above, but each component is described separately in Table 4.
(F-2): Cerium oxide powder having an average particle diameter of about 14 μm

<Example 19-22, Comparative Example 8-9>
In addition to the above components, the following components were uniformly mixed to prepare a curable silicone composition so as to have the composition shown in Table 5. Note that SiH / Vi in the table indicates the number of moles of silicon atom-bonded hydrogen atom in the component (B) with respect to a total of 1 mol of the alkenyl group in the component (A).

As the component (A), in addition to the above components (a-1) and (a-2), the following components were used.
(A-5): Copolymer of dimethylvinylsiloxy group-sealed dimethylvinylsyloxy group at both ends of molecular chain having a viscosity of 340 mPa · s (vinyl group content = about 1.17% by mass)

As the component (B), the above component (b-1) was used.

As the component (C), the following components were used in addition to the above component (c-2).
(C-3): A capsule-type catalyst having a glass transition point of about 65 ° C., in which a 1,3-divinyltetramethyldisiloxane solution of platinum 1,3-divinyltetramethyldisiloxane complex is microencapsulated with an acrylic resin. Molecular chain with a viscosity of 2,200 mPa · s containing 40% by mass Vinyl dimethylsiloxy group-sealed dimethylpolysiloxane dispersion (platinum metal content = about 4,000 ppm)

Moreover, the above-mentioned component (e-1) was used as the component (E).

Moreover, the following component was used as the component (F).
(F-3): Fumeed silica having a BET specific surface area of 400 m ² / g

In Examples 19-22 and Comparative Example 8-9, the component (f-3) was blended as a silica masterbatch prepared as follows, but in Table 5, each component is described separately. ..

<Preparation of silica masterbatch>
100 parts by mass of the above (a-2) component, 50 parts by mass of the above (f-3) component, 10 parts by mass of hexamethyldisilazane, 0.36 parts by mass of tetramethyldivinylsilazane, 2 parts by mass of water, and a viscosity of 20 mPa · s. Dimethyl hydroxysiloxy group-sealed dimethyl siloxane / methyl vinyl siloxane copolymer at both ends of the molecular chain (vinyl group content = about 10.9% by mass) Add 0.26 parts by mass to a loss mixer and mix until uniform at room temperature. Then, the mixture was heat-treated at 200 ° C. for 2 hours under reduced pressure to prepare a fluid silica master batch.

The curable silicone composition of the present invention has good curability and has a sufficient pot life at room temperature. Therefore, for example, silicone used for mold molding, compression molding, transfer molding, injection molding, extrusion molding, or calendar molding. Suitable as a material.

Claims (6)

(A) 100 parts by mass of an organopolysiloxane having at least two alkenyl groups in one molecule,
(B) Organopolysiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule (A) For a total of 1 mol of alkenyl groups in the component, the silicon atom-bonded hydrogen atom in this component is 0.1 to 0.1 to Amount of 10 mol,
(C) Catalyst for hydrosilylation reaction of catalytic amount, and (D) general formula:

(In the formula, each R ¹ is independently an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 3 to 6 carbon atoms, except that at least one R ¹ is the alkenyl group and each R ² is an alkenyl group. Independently, it is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
A curable silicone composition consisting of at least 0.001 to 0.3 parts by mass of a glycoluril compound represented by. The component (B) is the formula: HR ₂ SiO _1/2 (in the formula, each R is an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms. The curable silicone composition according to claim 1, which is an organopolysiloxane having a siloxane unit represented by (or a fluoroalkyl group having 3 to 12 carbon atoms). The component (B) is a siloxane unit represented by the formula: HR ₂ SiO _1/2 (in the formula, each R is independently the same group as described above), and the formula: SiO _4/2 . The curable silicone composition according to claim 2, which is an organopolysiloxane having a siloxane unit. The component (B) is represented by a siloxane unit represented by the formula: HR ₂ SiO _1/2 and a formula: RSiO _3/2 (in the formula, each R is independently the same group as described above). The curable silicone composition according to claim 2, which is an organopolysiloxane having a siloxane unit. The component (D) is the formula:

The curable silicone composition according to claim 1, which is a glycoluril compound represented by. The curable silicone composition according to claim 1, further comprising (E) a hydrosilylation reaction inhibitor other than the component (D).