JP2004204225A - One-pack type organopolysiloxane gel composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart long period storage stability at room temperature to a one-pack type organopolysiloxane gel composition comprising an organohydrogenpolysiloxane having a hydrogen atom at a molecule chain terminal, a branched organopolysiloxane having a vinyl group, and a platinum catalyst. <P>SOLUTION: This one-pack type organopolysiloxane gel composition comprises (A) the branched organopolysiloxane having the vinyl group, (B) the organohydrogenpolysiloxane having the hydrogen atom at the molecule chain terminal, (C) the platinum catalyst, (D) a phosphite triester, and (E) an organic peroxide. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a one-part organopolysiloxane gel composition, and more particularly to a one-part organopolysiloxane gel composition having good long-term storage stability at room temperature.

  Conventionally, it contains an organohydrogenpolysiloxane having a hydrogen atom (SiH) bonded to a silicon atom, an organopolysiloxane having an alkenyl group such as a vinyl group bonded to a silicon atom, and a platinum-based catalyst. An addition reaction-curable organopolysiloxane composition (hereinafter simply referred to as “composition”), which obtains a cured product by an addition reaction (hydrosilylation reaction) to a compound, is mixed with a platinum-based catalyst and various addition reaction inhibitors, It is well known that the progress of curing due to the addition reaction at room temperature is suppressed to improve long-term storage stability, and that the addition reaction is accelerated by heating to cure the resin during use. For example, it is known to add an acetylene compound (Patent Document 1), a sulfoxide compound (Patent Document 2), or a hydroperoxide compound (Patent Document 3) as an addition reaction inhibitor.

However, for example, when an organohydrogenpolysiloxane having a monofunctional unit represented by the formula: H (CH ₃ ) ₂ SiO _0.5 , that is, using an organohydrogenpolysiloxane having SiH at a molecular chain terminal, is used, the above reaction inhibitor is used. Even if it is blended, the progress of curing by the addition reaction of the composition at room temperature cannot be effectively suppressed, so that the storage stability of the composition was not sufficient. Furthermore, in the case of a composition that is a combination of the above-mentioned organohydrogenpolysiloxane having SiH at the molecular chain terminal and an alkenyl group-containing organopolysiloxane having a branched structure, long-term storage stability at room temperature can be achieved. It was even more difficult.

  In order to solve these problems, n-butylamine, N, N, as an addition reaction inhibitor at room temperature of a composition containing a vinyl group-containing branched organopolysiloxane and an organohydrogenpolysiloxane having SiH at a molecular chain end is used. It has been proposed to use amine compounds such as N-dibutylaminopropylamine and N, N, N ', N'-tetramethylethylenediamine (Patent Document 4). However, these amine compounds have poor storage stability in open systems due to their low boiling points, and when an inorganic filler is blended in the composition, it is adsorbed on the surface of the inorganic filler, It has not been effective yet because it has a drawback that the effect of suppressing the addition reaction is significantly reduced.

  On the other hand, compositions in which a phosphite is blended as an addition reaction inhibitor are known (Patent Document 5, Patent Document 6, Patent Document 7), and a phosphorus compound and an organic peroxide are used as an addition reaction inhibitor. It is also known to use (Patent Document 8). However, in any of the above patent documents, when a phosphite is used as an addition reaction inhibitor, an addition reaction at room temperature can be effectively performed in a composition containing an organohydrogenpolysiloxane having SiH at a molecular chain terminal. No mention is made of what can be suppressed. Further, in the case of a composition containing a combination of an organohydrogenpolysiloxane having SiH at a molecular chain terminal and an alkenyl group-containing organopolysiloxane having a branched structure, a phosphite or a phosphite and an organic peroxide are used. No mention is made of the fact that addition reaction at room temperature can be suppressed by combination with an oxide.

U.S. Pat. No. 3,445,420 U.S. Pat. No. 3,453,234 U.S. Pat. No. 4,061,609 U.S. Pat. No. 4,584,361, U.S. Pat. No. 3,188,300, JP 2001-508096 A JP 2001-527111 A JP-A-56-20051

  Therefore, an object of the present invention is to provide a composition comprising a combination of an organohydrogenpolysiloxane having SiH at a molecular chain end and an alkenyl group-containing organopolysiloxane having a branched structure, It is an object of the present invention to provide a one-part organopolysiloxane gel composition in which an addition reaction at room temperature is effectively suppressed even when an inorganic filler is incorporated therein, and storage stability is maintained for a long period of time.

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention.
That is, the present invention
(A) R (CH ₃ ) SiO unit: 80.0 to 97.0 mol%, RSiO _1.5 unit: 1.0 to 10.0 mol%, (CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 unit: 0.1 to 4.0 mol%, and ( CH ₃ ) ₃ SiO _0.5 unit: 0.5 to 10 mol%
[However, the total of these units is 100 mol%, and in each of the above unit formulas representing these units, R is a methyl group, a phenyl group, or a compound represented by the formula: RfCH ₂ CH _2- (Rf is an ether in the chain. A perfluoroalkyl group having or not having a binding oxygen atom)]
A plurality of Rs contained in one molecule are the same or different, organopolysiloxane: 100 parts by weight,
Formula (B): H (R ¹ ) ₂ SiO _0.5
[Wherein, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group other than an alkenyl group]
An organohydrogenpolysiloxane having at least two units in one molecule represented by the following formula: wherein the number of hydrogen atoms bonded to silicon atoms contained in this component is vinyl contained in the organopolysiloxane of component (A) 0.5-4.0 pieces per base,
(C) Platinum-based catalyst: effective amount,
(D) Phosphorous triester: an amount in which the amount of phosphorus atoms in the component is 2 mol or more per 1 mol of platinum metal atoms contained in the component (C), and (E) an organic peroxide A one-part organometallic compound, wherein the amount of -OO- bonds in the component is 2 mol or more per 1 mol of phosphorus atom contained in the component (D). A siloxane gel composition is provided.

  The present invention has conventionally been impossible to store at room temperature for a long period of time, and has an organohydrogenpolysiloxane having a hydrogen atom at a molecular chain terminal bonded to a silicon atom, and an aliphatic unsaturated group bonded to a silicon atom. One-part organopolysiloxane gel compositions containing a branched organopolysiloxane and a platinum-based catalyst that promotes the addition reaction, and long-term storage, even when the composition further contains an inorganic filler. It not only imparts stability but also has an excellent effect that it has no influence on the heat curability during use.

Hereinafter, the present invention will be described in more detail.
-(A) vinyl group-containing branched organopolysiloxane-
The organopolysiloxane of the component (A) is used as a main component (base polymer) of the composition of the present invention. As described above, R (CH ₃ ) SiO units: 80.0 to 97.0 mol%, RSiO _1.5 units: 1.0 110.0 mol%, (CH ₃ ) ₂ (CH ₂ ＣＨCH) SiO _0.5 unit: 0.1 to 4.0 mol%, and (CH ₃ ) ₃ SiO _0.5 unit: 0.5 to 10 mol% (the total of these units is 100 mol %).

R may be the same or different and may be a methyl group, a phenyl group, or a formula: RfCH ₂ CH ₂ — (Rf is a perfluoroalkyl group with or without an etheric oxygen atom in the chain. ).

When the perfluoroalkyl group for Rf does not have an etheric oxygen atom in the chain, it preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms. Include, for example, groups represented by the formulas: CF _3- , C ₄ F _9- , C ₈ F _17- and the like.

When Rf has an etheric oxygen atom in the chain, for example, the following general formula (1):
R'O- (R "O-) _p R"'-(1)
Wherein R ′ is a perfluoroalkyl group having 1 to 4 carbon atoms, R ″ and R ″ ′ are each independently a perfluoroalkylene group having 1 to 3 carbon atoms, and p is 0 to 10 Is an integer. ]
Is a group represented by Specifically, those represented by the following formulas are exemplified.
C ₂ F ₅ O- (CF ₂ CF ₂ O-) _s CF _{2-
C 3 F 7 O- (CF 2} CF 2 CF 2 O-) t CF 2 CF 2 -
_{C 3 F 7 O- [CF (} CF 3) CF 2 O-] t CF (CF 3) -
[In the above formula, s is an integer of 0 to 4, and t is an integer of 0 to 10.]

The trifunctional unit represented by the above formula: RSiO _1.5 in the component (A) has a structure in which the organopolysiloxane of the component (A) has a branched structure, and the composition of the present invention has a low-temperature property and a high speed. It is an important unit for providing curing performance. As described above, the content of this unit is 1.0 to 10.0 mol%, preferably 1.5 to 10.0 mol%, and when the content is less than 1.0 mol%, the linear structure of the component (A) increases. Therefore, the above properties and performances are insufficiently imparted. Conversely, if it exceeds 10.0 mol%, it becomes difficult to control the viscosity.

Further, the monofunctional units represented by the above formula: (CH ₃ ) ₂ (CH ₂ ＣＨCH) SiO _0.5 and the formula: (CH ₃ ) ₃ SiO _0.5 are all units that serve as terminal groups. The content of the former is 0.1 to 4.0 mol%, preferably 0.5 to 3.0 mol%. When the content is less than 0.1 mol%, the curing properties due to the addition reaction are poor, and when the content exceeds 4.0 mol%, the content exceeds 4.0 mol%. There is a problem that the heat resistance of the cured product is poor. The content of the latter is 0.5 to 10 mol%, preferably 0.8 to 8 mol%, and the total content of the former and the latter is the content of the trifunctional unit represented by the above formula: RSiO _1.5. (That is, the ratio of the branched structure in the component (A)).

  The organopolysiloxane of the component (A) can be produced by a known method. For example, a method in which chlorosilanes corresponding to the above units are mixed at a required molar ratio and subjected to cohydrolysis and condensation, or an equilibrium reaction of a polysiloxane and / or a cyclic siloxane compound having a structure of the above units, Manufactured.

  It is preferable that the viscosity of the organopolysiloxane (A) at 25 ° C. is usually in the range of 300 to 10,000 mPa · s.

Specific examples of the organopolysiloxane of the component (A) are shown below, but it should not be construed that the invention is limited thereto.
[(CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 ] _a [(CH ₃ ) ₃ SiO _0.5 ] _b [(CH ₃ ) ₂ SiO] _c [CH ₃ SiO _1.5 ] _d
[(CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 ] _a [(CH ₃ ) ₃ SiO _0.5 ] _b [(CH ₃ ) ₂ SiO] _c [CH ₃ SiO _1.5 ] _d [Ph ₂ SiO] _e
[(CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 ] _a [(CH ₃ ) ₃ SiO _0.5 ] _b [(CH ₃ ) ₂ SiO] _c [CH ₃ SiO _1.5 ] _d [(CH ₃ ) PhSiO] _f
[(CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 ] _a [(CH ₃ ) ₃ SiO _0.5 ] _b [(CH ₃ ) ₂ SiO] _c [PhSiO _1.5 ] _g
[(CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 ] _a [(CH ₃ ) ₃ SiO _0.5 ] _b [CH ₃ SiO _1.5 ] _d [(CH ₃ ) CF ₃ CH ₂ CH ₂ SiO] _h
[(CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 ] _a [(CH ₃ ) ₃ SiO _0.5 ] _b [CH ₃ SiO _1.5 ] _d [(CH ₃ ) C ₃ F ₇ O- {CF (CF ₃ ) CF ₂ O-} iCF (CF ₃ ) CH ₂ CH ₂ SiO] _j
[(CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 ] _a [(CH ₃ ) ₃ SiO _0.5 ] _b [(CH ₃ ) ₂ SiO] _c [PhSiO _1.5 ] _k
(In the above formulas, a, b, c, d, e, f, g, h, i, j, and k are each a positive integer selected to satisfy the above viscosity, and Ph is a phenyl group (C ₆ H _5- ).)
These organopolysiloxanes can be used alone or in combination of two or more.

-(B) organohydrogenpolysiloxane-
The organohydrogenpolysiloxane that is the component (B),
Formula: H (R ¹ ) ₂ SiO _0.5
[Wherein, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group other than an alkenyl group]
And at least two monofunctional diorganohydrogensiloxy units in one molecule. That is, in this organohydrogenpolysiloxane, a hydrogen atom is bonded to at least two silicon atoms at molecular terminals.

R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having preferably 1 to 12, more preferably 1 to 8 carbon atoms, and specifically, for example, methyl, ethyl, propyl An alkyl group such as a butyl group or a butyl group; a cycloalkyl group such as a cyclohexyl group; an aryl group such as a phenyl group or a tolyl group; an aralkyl group such as a benzyl group or a β-phenylpropyl group; A part or all of the hydrogen atom is a halogen atom, a chloromethyl group substituted with a cyano group, a 3,3,3-trifluoropropyl group, a 2-cyanoethyl group, and the like, among which a methyl group, a phenyl group, A 3,3,3-trifluoropropyl group is preferred.

As this organohydrogenpolysiloxane, for example, the following average composition formula (2):
(H) _a (R ⁶ ) _b SiO _{(4-ab) / 2} (2)
And at least two units represented by the formula: H (R ¹ ) ₂ SiO _0.5 (R ¹ is as described above) in one molecule.
In this average composition formula (2), a plurality of R ⁶ are independently the same unsubstituted or substituted monovalent hydrocarbon group as defined for R ¹ above. Alternatively, two R ⁶ 's may form a lower alkylene group together.

When R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group, the same groups as those for R ¹ can be mentioned, and among them, a methyl group, a phenyl group, and a 3,3,3-trifluoropropyl group are preferable.
Examples of the lower alkylene group formed by combining two R ⁶ groups include an ethylene group, a trimethylene group, a methylmethylene group, a tetramethylene group, and a hexamethylene group.
A is a number satisfying 0 <a ≦ 2, b is a number satisfying 0 <b ≦ 3, and 0 <a + b ≦ 3, preferably 0.001 ≦ a ≦ 0.5, 0.8 ≦ b ≦ 2.2, 1 ≦ a + b ≦ 2.4.

As described above, the organohydrogenpolysiloxane represented by the average composition formula (2) is a compound containing at least two units represented by the formula: H (R ¹ ) ₂ SiO _0.5 in one molecule. The structure is not particularly limited, and may be a linear or branched structure.

In addition, the organohydrogenpolysiloxane of the component (B) has a viscosity at 25 ° C of 1,000 mPas or less, usually 0.1 to 1000 mPas, particularly 0.5 to 500 mPas in terms of easy synthesis. s is preferred.
When the component (B) is a linear organohydrogenpolysiloxane, for example, the following general formula (3):

（式中、Ｒ¹およびＲ⁶は上記のとおりであり、ｃおよびｄは同一または異なる０または正数であり、ｃ＋ｄは上記粘度を満足する数である）
で表すことができる。

(Wherein R ¹ and R ⁶ are as described above, c and d are the same or different 0 or a positive number, and c + d is a number satisfying the above viscosity)
Can be represented by

In addition, as the branched organohydrogenpolysiloxane, a unit represented by the formula: R ⁶ SiO _1.5 (R ⁶ is as described above), a unit represented by the formula: SiO ₂ , or The following structural formula (4):

（式中、Ｒ⁶は上記のとおりである）
で表される単位等を有するものを挙げることができる。

(Wherein R ⁶ is as described above)
And those having a unit represented by

Specific examples of the organohydrogenpolysiloxane of the component (B) of the present invention are shown below, but are not limited thereto.
Dimethylpolysiloxane terminated at both ends of the molecular chain with dimethylhydrogensiloxy group, methylphenylpolysiloxane terminated at both ends of the molecular chain with dimethylhydrogensiloxy group, terminated at both ends of the molecular chain with dimethylhydrogensiloxy group Dimethylsiloxane / methylphenylsiloxane copolymer, dimethylsiloxane / methylhydrogensiloxane copolymer terminated at both molecular chains with dimethylhydrogensiloxy groups, molecular chain both ends terminated with dimethylhydrogensiloxy groups Dimethyl siloxane / methyl hydrogen siloxane / methyl phenyl siloxane copolymer, dimethyl siloxane / methyl trifluoropropyl siloxane copolymer terminated at both molecular chains with dimethyl hydrogen siloxy groups Formula siloxane units of the formula R ¹ ₃ SiO _0.5: siloxane units represented by the formula R ¹ ₂ HSiO _0.5: organopolysiloxane copolymers composed of siloxane units represented by SiO _2, wherein: R ¹ ₂ HSiO siloxane units of the formula _0.5: organopolysiloxane copolymers composed of siloxane units represented by SiO _2, wherein: the siloxane units represented by the formula R ¹ ₂ HSiO _0.5: siloxane units represented by R ¹ SiO _1.5 organopolysiloxane copolymers consisting formula: siloxane units represented by the formula R ¹ ₂ HSiO _0.5: siloxane units represented by the formula R ¹ ₂ SiO: R ¹ organopolysiloxane copolymer consisting of siloxane units represented by SiO _1.5 Polymer (in each of the above formulas, R ¹ is as defined above).
These organohydrogenpolysiloxanes can be used alone or in combination of two or more.

  The blending ratio of the component (B) in the composition of the present invention is such that the obtained cured product has good physical properties such as heat resistance and mechanical strength and does not need to be foamed during curing. The number of hydrogen atoms bonded to silicon atoms contained in the component (B) is from 0.5 to 4.0, particularly from 0.8 to 4.0 per vinyl group contained in the organopolysiloxane of the component (A). Preferably, the ratio is 3.0.

− (C) Platinum catalyst−
The platinum catalyst of the component (C) is added to promote the addition reaction between the vinyl group in the component (A) and the SiH in the component (B), and to obtain a cured product of the composition of the present invention. It is a well-known component.

  As the component (C), for example, the following general formula (5):

、下記一般式(6)：

And the following general formula (6):

［上記各式中、Ｒ⁷は独立に非置換または置換の１価炭化水素基であり、ｍは０〜３、ｎは３〜６、ｍ＋ｎの和は３〜９の整数である］
等で表されるビニル基含有オルガノポリシロキサンを配位子とする白金錯体が好適に用いられる。

[In each of the above formulas, R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group, m is an integer of 0 to 3, n is 3 to 6, and the sum of m + n is an integer of 3 to 9.]
Platinum complexes having a vinyl group-containing organopolysiloxane as a ligand are preferably used.

R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group having preferably 1 to 12, more preferably 1 to 8, carbon atoms, such as methyl, ethyl, propyl, butyl and the like. An alkenyl group such as a vinyl group, an allyl group, or a propenyl group; a cycloalkyl group such as a cyclohexyl group; an aryl group such as a phenyl group or a tolyl group; an aralkyl group such as a benzyl group or a β-phenylpropyl group; Some or all of the hydrogen atoms bonded to the carbon atoms of these groups are halogen atoms, a chloromethyl group substituted with a cyano group, a 3,3,3-trifluoropropyl group, a 2-cyanoethyl group, and the like. Among them, a methyl group, a vinyl group, a phenyl group, and a 3,3,3-trifluoropropyl group are preferred.

  The component (C) which is a platinum complex is known, and is represented by, for example, chloroplatinic acid and the above-mentioned general formulas (5) and (6), as described in JP-B-47-23679. It can be produced by heating and reacting with a low molecular weight siloxane in the presence of a basic salt.

Specific examples of the platinum catalyst of the component (C) of the present invention include, for example, platinum / 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, platinum / 2,4,6,8 -Tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane complex and the like, but are not limited thereto.
In addition, a platinum-type catalyst can be used individually by 1 type or in combination of 2 or more types.

  The blending amount of the component (C) with respect to the composition of the present invention is not particularly limited as long as it is an effective amount as a catalyst, but is not particularly limited, and the weight of the platinum metal atom is based on the total amount of the components (A) and (B). Usually, it may be blended in the range of about 0.5 to 500 ppm, preferably about 1 to 100 ppm, more preferably about 5 to 50 ppm. If the amount is too small, the addition reaction will be remarkably slow or will not be cured.If the amount is too large, the heat resistance of the cured polysiloxane composition will be reduced. At a disadvantage.

-(D) phosphite triester-
The component (D) preferably has the general formula: P (OR ² ) ₃
Wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group and a formula: —R ⁴ [—OP (OR ³ ) ₂ ] _x (wherein, R ³ is independently unsubstituted or substituted Wherein x is an integer of 1 to 3, and R ⁴ is a divalent to tetravalent hydrocarbon having 2 to 20 carbon atoms with or without an etheric oxygen atom in the chain. At least one group selected from the group consisting of groups represented by
A phosphite triester represented by the following general formula:

［式中、Ｒ³は前記と同じであり、Ｒ⁵は鎖中にエーテル結合性酸素原子を有する、または有しない炭素原子数１〜20の４価の炭化水素基である］
で表される亜リン酸トリエステルである。この(D)成分は、上記(C)成分の白金系触媒の室温における付加反応に対する触媒能を抑制する機能を有する

Wherein R ³ is the same as described above, and R ⁵ is a tetravalent hydrocarbon group having 1 to 20 carbon atoms having or not having an etheric oxygen atom in the chain.
Is a phosphite triester represented by This component (D) has a function of suppressing the catalytic ability of the platinum-based catalyst of the component (C) to an addition reaction at room temperature.

R ² is an unsubstituted or substituted monovalent hydrocarbon group having preferably 1 to 20, more preferably 1 to 15, carbon atoms, such as a methyl group, an ethyl group, a propyl group, and a butyl group. Alkyl groups such as pentyl group, hexyl group, octyl group, isopropyl group, isobutyl group, tert-butyl group, neopentyl group and 2-ethylhexyl group; alkenyl groups such as vinyl group, allyl group and propenyl group; cyclohexyl group etc. An aryl group such as a phenyl group or a tolyl group; an aralkyl group such as a benzyl group or a β-phenylpropyl group; and a halogen atom, a cyano A chloromethyl group, a 3,3,3-trifluoropropyl group, a 2-cyanoethyl group and the like substituted with a group.

R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group, and examples thereof include the same as those exemplified as the unsubstituted or substituted monovalent hydrocarbon group in R ² .
R ⁴ is a divalent to tetravalent hydrocarbon group having 2 to 20, preferably 2 to 12 carbon atoms having or not having an etheric oxygen atom in the chain.
R ⁵ is a tetravalent hydrocarbon group having 1 to 20 carbon atoms, preferably 5 to 20 carbon atoms, with or without an etheric oxygen atom in the chain.

Specific examples of the phosphite triester of the component (D) of the present invention are shown below, but it should not be construed that the invention is limited thereto.
Triethyl phosphite: (EtO) ₃ P, trioctyl phosphite: [Me (CH ₂ ) ₇ O] ₃ P, tris (2-ethylhexyl) phosphite: [MeC ₃ H ₆ CH (Et) CH ₂ O] ₃ P, triphenyl phosphite: (PhO) ₃ P, diphenyl mono (2-ethylhexyl) phosphite: (PhO) ₂ (MeC ₃ H ₆ CH (Et) CH ₂ O) P, tris (2,4-di- tert-butylphenyl) phosphite:

、テトラフェニルジプロピレングリコールジフォスファイト：(ＰｈＯ)₂ＰＯ-[ＣＨ(Ｍｅ)-ＣＨ₂Ｏ]₂-Ｐ(ＯＰｈ)₂、テトラフェニルテトラ(トリデシル)ペンタエリスリト−ルテトラホスファイト：[(ＰｈＯ)(Ｃ₁₃Ｈ₂₇Ｏ)Ｐ-ＯＣＨ₂]₄Ｃ、テトラ(トリデシル)-4,4'-イソプロピリデンジフェニルジホスファイト：(Ｃ₁₃Ｈ₂₇Ｏ)₂ＰＯ-Ｐｈ-Ｃ(Ｍｅ)₂-Ｐｈ-ＯＰ(ＯＣ₁₃Ｈ₂₇)₂、ビス(トリデシル)ペンタエリスリトールジホスファイト：

, Tetraphenyl dipropylene glycol _{diphosphite: (PhO) 2 PO- [CH} (Me) -CH 2 O] 2 -P (OPh) 2, tetraphenyl tetra (tridecyl) pentaerythritol - Le tetraphosphite: [ _{(PhO) (C 13 H 27} O) P-OCH 2] 4 C, tetra (tridecyl) -4,4'-isopropylidene diphenyl _{diphosphite: (C 13 H 27 O)} 2 PO-Ph-C (Me ) ₂ -Ph-OP (OC ₁₃ H ₂₇ ) ₂ , bis (tridecyl) pentaerythritol diphosphite:

（上記式中、Ｍｅ、Ｅｔ、Ｂｕは、それぞれ、メチル基、エチル基、ブチル基を示し、Ｐｈは、フェニル基またはフェニレン基を示す。）
これらの亜リン酸トリエステルは、１種単独でも２種以上組み合わせても使用することができる。

(In the above formula, Me, Et, and Bu represent a methyl group, an ethyl group, and a butyl group, respectively, and Ph represents a phenyl group or a phenylene group.)
These phosphite triesters can be used alone or in combination of two or more.

  The compounding amount of the phosphite triester of the component (D) is such that the amount of the phosphorus atom in the component (D) is at least 2 mol per 1 mol of the platinum metal atom contained in the component (C). Preferably, the amount is 3 mol or more. If the amount is less than 2 mol, the catalytic ability of the platinum-based catalyst at room temperature for the addition reaction cannot be completely suppressed. The upper limit of the amount of the phosphite triester is not particularly limited because it varies depending on the coordinating ability of the phosphite triester to the platinum metal atom and the oxidizing ability of the component (E). Since it is necessary not to impair the curability, the blending amount may be about 2 to 10 mol.

− (E) Organic peroxide−
The organic peroxide of the component (E) has a function of effectively suppressing the catalytic ability of the platinum-based catalyst against the addition reaction together with the component (D) during long-term storage of the composition at room temperature. In addition, in the heat curing step, the function of decomposing at the decomposition temperature and losing its own inhibitory action and oxidizing the component (D) also inactivates the inhibitory action of the component (D). The curing of the composition by the platinum-based catalyst can be performed quickly and reliably.

  Examples of the organic peroxide include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexane nonperoxide, methyl acetoacetate peroxide, and acetylacetone peroxide; 1,1-bis (t-butylperoxy) -3,3 Peroxyketals such as 1,5-trimethylcyclohexane and 2,2-bis (t-butylperoxy) butane; 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide Hydroperoxides such as oxides; dialkyl peroxides such as 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane and di-t-butyl peroxide; 3,5,5-trimethylhexanoylperoxide Diacyl peroxides such as oxide and m-toluyl peroxide; diisopropyl peroxydica Peroxycarbonates such as carbonate and di-2-ethylhexylperoxydicarbonate; t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy / isopropyl monocarbonate, t-butylperoxy Peroxyesters such as 2-ethylhexyl monocarbonate and t-butylperoxybenzoate; and the like. These can be used alone or in combination of two or more.

  The amount of the component (E) is such that the amount of -OO- bonds in the component (E) is at least 2 moles, preferably at least 3 moles, per mole of phosphorus atoms contained in the component (D). Is the amount If the compounding amount is less than 2 mol, the catalytic ability for the addition reaction of the platinum-based catalyst at room temperature cannot be completely suppressed, and the catalytic ability suppressing action of the component (D) is completely deactivated in the heat curing step. I can't. The upper limit of the amount of the organic peroxide is not particularly limited. However, the amount of the organic peroxide may be about 15 mol because the residue of the decomposition affects the curing properties.

-Other ingredients-
In the composition of the present invention, as the optional components to be added in addition to the components (A) to (E), for example, fumed silica, crystalline silica, precipitated silica, hollow filler, silsesquioxane, fumed titanium dioxide Inorganic fillers such as magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, zinc carbonate, layered mica, carbon black, diatomaceous earth, and glass fiber; and these fillers are organoalkoxy. A filler surface-treated with an organosilicon compound such as a silane compound, an organochlorosilane compound, an organosilazane compound, or a low-molecular-weight siloxane compound may be blended. Further, silicone rubber powder, silicone resin powder, and the like may be blended.

  Further, the composition of the present invention does not contain, as an optional component, for example, a linear organopolysiloxane containing an alkenyl group, a silicon atom-bonded hydrogen atom and an alkenyl group as long as the object of the present invention is not impaired. An organopolysiloxane, a heat resistance-imparting agent, a flame retardancy-imparting agent, a thixotropy-imparting agent, a pigment, a dye, and the like may be blended.

[Example 1]
(A) CH ₂ = CH (CH ₃ ) ₂ SiO _0.5 unit / (CH ₃ ) ₃ SiO _0.5 unit / (CH ₃ ) ₂ SiO unit / CH ₃ SiO _1.5 unit = 0.7 mol% / 7 mol% / 83.2 mol% /9.1 mol%, and 100 parts of an organopolysiloxane having a viscosity at 25 ° C. of 2,000 mPa · s, wherein (B) the content of hydrogen atoms (SiH) bonded to silicon atoms is 0.068% by weight. Dimethylpolysiloxane terminated with a dimethylhydrogensiloxy group, 10 parts (number of SiH / number of vinyl groups in component (A) = 0.7), (C) chloroplatinic acid / 1,3-divinyltetramethyl 0.05 parts of disiloxane complex (platinum metal atom content: 1% by weight) (5 ppm with respect to the total amount of (A) + (B) as platinum metal atom weight), 0.0032 parts of (D) trioctyl phosphite ( (Phosphorus atom in the component / platinum metal atom in the (C) component (molar ratio) = 3) and (E) t-butylperoxy.3 0.012 parts of (5,5-trimethylhexanoate) (-OO-bond in the component / phosphorus atom in the (D) component (molar ratio) = 6.5) was uniformly mixed to obtain a composition. The resulting composition was allowed to stand in a closed system in a container at 40 ° C. for one month, but the composition did not thicken at all.

  Then, the composition was cured by heating at 130 ° C. for 30 minutes to obtain a transparent gel. The hardness of this gel was measured in accordance with JIS K 2220 (1/4 cone) consistency test method, and was found to be 20. The composition obtained by mixing the above components (A) to (E) was immediately heated and cured under the same conditions as above, and the gel-like product obtained had a hardness of 20 similarly.

[Example 2]
(A) CH ₂ = CH (CH ₃ ) ₂ SiO _0.5 unit / (CH ₃ ) ₃ SiO _0.5 unit / (C ₆ H ₅ ) ₂ SiO unit / (CH ₃ ) ₂ SiO unit / CH ₃ SiO _1.5 unit = 0.85 100 parts of an organopolysiloxane having a molar ratio of mol% / 0.9 mol% / 2.1 mol% / 94.65 mol% / 1.5 mol% and a viscosity at 25 ° C. of 1,000 mPa · s, and the terminal was blocked with a trimethylsiloxy group. 60 parts of a dimethylsiloxane-diphenylsiloxane copolymer containing 3 mol% of diphenylsiloxane units having a viscosity at 25 ° C. of 700 mPa · s, and (B1) a content of hydrogen atoms bonded to silicon atoms of 0.068% by weight. Dimethylpolysiloxane terminated with a dimethylhydrogensiloxy group at 6.9 parts, the content of (B2) silicon-bonded hydrogen atoms is 0.04% by weight, and 50% of the terminal is a dimethylhydrogensiloxy group. Stopped and left 12 parts of dimethylpolysiloxane end-capped with trimethylsiloxy groups (number of SiH in (B1) + (B2) / number of vinyl groups in (A) = 0.9), (C) chloroplatinic acid / 1 0.05 part of 3,3-divinyltetramethyldisiloxane complex (platinum metal atom content: 1% by weight) (5 ppm based on the total amount of (A) + (B1) + (B2) as platinum metal atom weight), (D) 0.00235 parts of triphenyl phosphite (phosphorus atom in the component / platinum metal atom in the component (C) (molar ratio) = 3), (E) 1,1-bis (t-butylperoxy)- 0.0075 parts of 3,3,5-trimethylcyclohexane (-OO-bond in the component / phosphorus atom (molar ratio) in the component (D) = 6.5) was uniformly mixed to obtain a composition.

The resulting composition was allowed to stand in a closed system in a container at 40 ° C. for one month, but the composition did not thicken at all.
Then, the composition was cured by heating at 130 ° C. for 30 minutes to obtain a transparent gel. The hardness of this gel was measured in accordance with JIS K 2220 (1/4 cone) consistency test method, and as a result, it was 115. The composition obtained by mixing the above components (A) to (E) was immediately heated and cured under the same conditions as above, and the gel-like product obtained had a hardness of 115 similarly.

[Example 3]
(A) CH ₂ = CH (CH ₃ ) ₂ SiO _0.5 unit / (CH ₃ ) ₃ SiO _0.5 unit / (CH ₃ ) ₂ SiO unit / CH ₃ SiO _1.5 unit = 1.24 mol% / 2.7 mol% / 92.86 mol% 100 parts of an organopolysiloxane having a molar ratio of /3.2 mol% and a viscosity of 400 mPa · s at 25 ° C., (B) the content of hydrogen atoms bonded to silicon atoms is 0.13% by weight, 8 parts of dimethylpolysiloxane terminated by a gensiloxy group (number of SiH / number of vinyl groups in component (A) = 0.6), (C) chloroplatinic acid / 1,3-divinyltetramethyldisiloxane complex (platinum Metal atom content: 1% by weight) 0.05 part (5 ppm based on the total amount of (A) + (B) as platinum metal atom weight), (D) trioctyl phosphite 0.0032 part (phosphorus content in the component) Atom / platinum metal atom in component (C) (molar ratio) = 3), (E1) 1,1-bis (t-butylperoxy) -3,3,5-tri 0.0064 parts (-OO-bond in the component / phosphorus atom (molar ratio) in component (D) = 5.5), 0.0024 parts (E2) methyl acetoacetate peroxide (-OO-bond / The phosphorus atom (molar ratio) in component (D) = 1) was uniformly mixed to obtain a composition.

When the obtained composition was left at 40 ° C. in a closed system in a container, the viscosity was significantly increased after 20 days.
Then, the composition was cured by heating at 130 ° C. for 30 minutes to obtain a transparent gel. The hardness of this gel was measured in accordance with the JIS K 2220 (1/4 cone) consistency test method, and was 87. The composition obtained by mixing the above components (A) to (E) was immediately heated and cured under the same conditions as above, and the hardness of the gel obtained was 87 in the same manner.

[Example 4]
The composition was uniformly mixed in the same manner as in Example 2 except that 2 parts by weight of hydrophobic silica having a specific surface area of 170 m ² / g, which had been surface-treated with hexamethyldisilazane and had a trimethylsilyl group on the surface, was added. Obtained.

The obtained composition was stored in a closed system in a container at 40 ° C. for one month, but there was no thickening of the composition.
Then, the composition was cured by heating at 130 ° C. for 30 minutes to obtain a transparent gel. The hardness of this gel was measured in accordance with the JIS K 2220 (1/4 cone) consistency test method, and was 110. The hardness of the gel obtained by immediately heating and curing the composition obtained by mixing the components (A) to (E) and the hydrophobic silica under the same conditions as described above is 110%. Met.

[Comparative Example 1]
(E) A uniform composition was obtained in the same manner as in Example 1 except that 0.0019 part of t-butylperoxy-3,5,5-trimethylhexanoate was not used. The resulting composition was heated at 130 ° C. for 30 minutes but did not cure.

[Comparative Example 2]
Using (D) trioctyl phosphite 0.0011 parts (phosphorus atom in the component / platinum metal atom (molar ratio) in the component (C) = 1), (E) t-butylperoxy-3,5, A uniform composition was obtained in the same manner as in Example 1, except that 0.012 part of 5-trimethylhexanoate was not used.
After 24 hours at 25 ° C., the composition gelled, and the resulting gelled product had a penetration of 20.

[Comparative Example 3]
(E) 0.0018 parts of t-butylperoxy-3,5,5-trimethylhexanoate (-OO-bond in the component / phosphorus atom (molar ratio) in the component (D) = 1) Except for the above, a uniform composition was obtained in the same manner as in Example 1. The resulting composition was heated at 130 ° C. for 30 minutes but did not cure.

Claims (2)

(A) R (CH ₃ ) SiO unit: 80.0 to 97.0 mol%, RSiO _1.5 unit: 1.0 to 10.0 mol%, (CH ₃ ) ₂ (CH ₂ = CH) SiO _0.5 unit: 0.1 to 4.0 mol%, and ( CH ₃ ) ₃ SiO _0.5 unit: 0.5 to 10 mol%
[However, the total of these units is 100 mol%, and in each of the above unit formulas representing these units, R is a methyl group, a phenyl group, or a compound represented by the formula: RfCH ₂ CH _2- (Rf is an ether in the chain. A perfluoroalkyl group having or not having a binding oxygen atom)]
A plurality of Rs contained in one molecule are the same or different, organopolysiloxane: 100 parts by weight,
Formula (B): H (R ¹ ) ₂ SiO _0.5
[Wherein, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group other than an alkenyl group]
An organohydrogenpolysiloxane having at least two units in one molecule represented by the following formula: wherein the number of hydrogen atoms bonded to silicon atoms contained in this component is vinyl contained in the organopolysiloxane of component (A) 0.5-4.0 pieces per base,
(C) Platinum-based catalyst: effective amount,
(D) Phosphorous triester: an amount in which the amount of phosphorus atoms in the component is 2 mol or more per 1 mol of platinum metal atoms contained in the component (C), and (E) an organic peroxide A one-part organometallic compound, wherein the amount of -OO- bonds in the component is 2 mol or more per 1 mol of phosphorus atom contained in the component (D). Siloxane gel composition. The phosphite triester of the component (D) is:
General formula: P (OR ² ) ₃
Wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group and a formula: —R ⁴ [—OP (OR ³ ) ₂ ] _x (wherein, R ³ is independently unsubstituted or substituted Wherein x is an integer of 1 to 3, and R ⁴ is a divalent to tetravalent hydrocarbon having 2 to 20 carbon atoms with or without an etheric oxygen atom in the chain. At least one group selected from the group consisting of groups represented by
A phosphite triester represented by the following general formula:

Wherein R ³ is the same as described above, and R ⁵ is a tetravalent hydrocarbon group having 1 to 20 carbon atoms having or not having an etheric oxygen atom in the chain.
The composition according to claim 1, which is a phosphite triester represented by the formula: