JP7043304B2 - Phenyl-modified organopolysiloxane prepolymer composition - Google Patents

Description

The present invention generally relates to a phenyl-modified organopolysiloxane prepolymer composition, and specifically, a condensed phenyl-modified preparation prepared for obtaining a cured organopolysiloxane polymer having excellent flexibility and heat resistance. The present invention relates to an organopolysiloxane prepolymer composition.

The condensed organopolysiloxane prepolymer becomes a cured product having excellent heat resistance by forming a Si—O—Si bond having a high binding energy. The polymer having this bond has a spiral structure, so that it has flexibility and exhibits excellent weather resistance. However, in order to form this strong Si—O—Si bond, a condensation reaction by heat treatment at a high temperature of 180 ° C. or higher for several hours is required.

In recent years, the heat resistance required for members has increased due to high integration, miniaturization, and thinning, and the demand for use in an environment of 200 ° C. or higher or 250 ° C. or higher has become apparent. These members are required to have not only heat resistance but also thermal stress relaxation ability that can be used under a wide range of temperature conditions from high temperature to room temperature or cold conditions and sudden temperature change conditions (cold heat impact). For that purpose, not only heat resistance but also elasticity capable of alleviating thermal deformation of constituent members is required. For such applications, the above-mentioned condensed organopolysiloxane polymer is attracting attention as one of the few elastic materials to which it can be applied.

In particular, an organopolysiloxane prepolymer using alkoxysilane having a phenyl group and polydimethylsiloxane (PDMS) has flexibility and heat resistance, and can be used in an environment of 250 ° C. or higher. This condensed organopolysiloxane polymer composed of alkoxysilane having a phenyl group and polydimethylsiloxane (PDMS) can be used as a potting material such as a sealing material for a power module, and can also be blended with a ceramic filler to form a heat-resistant heat-dissipating sheet or adhere. It can also be used as an agent.

Adhesives are an application of condensed organopolysiloxane polymers. For joining members with different linear expansion rates such as metal, ceramics, and glass, it is necessary to use an adhesive that can relieve the stress generated between different materials at the joint during the above-mentioned thermal impact. That is, the heat-resistant adhesive needs to have low elasticity to relieve thermal stress. Organopolysiloxane prepolymers synthesized with alkoxysilanes having a phenyl group can relieve thermal stresses and are ideal for use in heat resistant adhesives. These techniques are described in WO2014 / 098189 (Patent Document 1) and WO2016 / 104621 (Patent Document 2).

These condensed organopolysiloxane polymers have the property of being able to maintain flexibility in an environment of 200 ° C. or higher, but require heat treatment at 180 ° C. or higher for several hours at the time of production. Therefore, depending on the application, it is the mainstream to use a curing acceleration catalyst such as a metal compound, an aminosilane compound, or a metal alkoxide for the purpose of low-temperature curing or short-time curing.

Prior arts such as the following Patent Documents 3 to 8 exist for a curing catalyst in a reaction between a siloxane polymer having a silanol group at the terminal and a compound having an alkoxide group.

WO2012 / 067153 (Patent Document 3) reports a technique for accelerating the curing of an organopolysiloxane having a silanol group or a hydrolyzable group bonded to a silicon atom at the terminal using a zinc compound. Zinc-based metal catalysts have a mild reaction, are highly homogeneous even when a thick film is cured, are easy to use, and are thermally stable.

Japanese Patent Application Laid-Open No. 2013-112686 (Patent Document 4) describes a non-tin metal condensation reaction catalyst and an alkoxysilyl group as a co-catalyst as a condensation reaction curing type catalyst of a composition containing an organopolysiloxane having a silanol group. The application of the contained compound is described. It is generally known to use alkoxides for curing condensed silicone.

Japanese Unexamined Patent Publication No. 2012-021118 (Patent Document 5) describes that an organic hafnium compound is effective as a condensation catalyst for silanol. Japanese Patent Application Laid-Open No. 2016-184751 (Patent Document 6) and Japanese Patent Application Laid-Open No. 2010-163602 (Patent Document 7) describe a condensation catalyst of silanol using an aluminum alkoxide or a zirconium compound.

WO2012 / 063822 (Patent Document 8) describes a technique in which an organotin compound having relatively high heat stability and an organozinc compound are used in combination. This technology has both heat resistance and transparency, and is useful as a practical technology in terms of price and handleability.

WO2014 / 098189 WO2016 / 104621 WO2012 / 067153 Japanese Unexamined Patent Publication No. 2013-112686 Japanese Unexamined Patent Publication No. 2012-021118 Japanese Unexamined Patent Publication No. 2016-184751 Japanese Unexamined Patent Publication No. 2010-163602 WO2012 / 063822

However, the zinc-based metal catalyst described in Patent Document 3 acts as a negative catalyst at 180 ° C. or higher. It is extremely difficult to use it with a power module or the like used at 200 ° C. or higher.

Further, the catalyst to which the alkoxysilyl group-containing compound described in Patent Document 4 is applied lacks stability except for Si-based alkoxides typified by tetraethoxysilane, and can be used universally in the atmosphere where moisture is present. The disadvantage is that there are few. Even when used in a nitrogen atmosphere, the reaction of alkoxides is rapid and relatively large inorganic clusters are formed. Therefore, it is difficult to develop mechanical strength, and it tends to be thermally unstable due to the contraction of clusters lacking in denseness.

The organic hafnium compound described in Patent Document 5 is limited to thin film applications, is a very expensive and unwieldy catalyst, and is not general purpose. In general, a metal compound catalyst having a higher curing promoting effect is more likely to become a negative catalyst at high temperatures.

When the metal compound catalyst using the aluminum alkoxide or the zirconium compound described in Patent Documents 6 and 7 is used, there is a problem that the coloring and the weight loss rate become large when used at 200 ° C. or higher.

In the technique in which the organotin compound and the organozinc compound described in Patent Document 8 are used in combination, the weight of the obtained organopolysiloxane resin is reduced even in the minimum blending amount at which the catalytic effect is exhibited in a high temperature environment of 200 ° C. or higher. ..

As described above, although it is an organopolysiloxane prepolymer having both flexibility and heat resistance, a heat treatment temperature of 180 ° C. or higher is required to obtain a cured product. Further, if some fine particles having a particle diameter of μm or less, such as carbon black used for imparting conductivity and alumina fine particles used for blending a heat dissipation sheet, are blended, there is a problem that curing is delayed. In the case of such a filler composite, it is unclear whether it is a reaction inhibition or the filler surface takes in the reactive groups of the prepolymer, but it is also necessary to raise the curing temperature to 180 ° C. or higher.

Curing of such a condensed type organopolysiloxane prepolymer and curing of a composite condensed type organopolysiloxane prepolymer containing a part of a fine powder filler require a high temperature and a long time. Therefore, even if it is good at the research level, there are major problems in the production process such as thermal deterioration of constituent parts and members, environmental load due to long-term use of heat source, and increase in product cost. Therefore, some kind of curing accelerator is required.

As the curing catalyst of the organopolysiloxane prepolymer, an amine-based silane coupling agent or a metal compound-based catalyst such as platinum or tin is often used. However, the former silane coupling agent-based curing agent cannot be used in an environment of 180 ° C. or higher, and has a problem of coloring. The latter metal compound catalyst-based curing agent has a negative catalytic action when the temperature exceeds 200 ° C., and has problems such as cleavage of the organopolysiloxane skeleton, all of which result in deterioration of heat resistance characteristics. Therefore, a catalyst capable of relaxing the curing conditions without impairing the characteristics of the organopolysiloxane polymer having high heat resistance has been desired.

The coloring of the amine-based silane coupling agent exhibits yellow, which is a deteriorated color that is avoided in practical materials. It easily reacts with silicon oligomers and metal alkoxides in organopolysiloxane prepolymers to show a deep yellow color, and can be used for potting materials that require design and optical system encapsulants that require transparency. Can not.

Therefore, an object of the present invention is to provide a prepolymer composition that solves the above-mentioned conventional problems and produces a phenyl-modified organopolysiloxane polymer that cures at a relatively low temperature and has excellent heat resistance.

As a result of the studies by the present inventors, a curing agent containing a polysiloxane having a triethoxysilyl terminal group in the molecule and a polysiloxane having a trimethoxysilyl terminal group in the molecule as a curing promoting component is used. As a result, it has been found that the phenyl-modified organopolysiloxane prepolymer, which produces a polymer capable of maintaining the heat resistance property of 200 ° C. or higher, can be cured by heat treatment at a relatively low temperature for a short time. Hereinafter, in the present specification, "curing" means that a prepolymer having fluidity changes to a state (polymer) in which fluidity is lost.

Based on such findings, the phenyl-modified organopolysiloxane prepolymer composition according to the present invention comprises at least a main agent (C) containing the phenyl-modified hybrid prepolymers (A) and (B) and a linear poly. It is made by mixing a curing agent (F) containing siloxane (D) and (E).

The phenyl-modified hybrid prepolymer (A) is produced by subjecting polydimethylsiloxane (PDMS-1) having a silanol group at both ends to a condensation reaction with at least one of phenyltrialkoxysilane and its hydrolyzate. Phenyl-modified hybrid prepolymer. Hereinafter, in the present specification, simply "hydrolysis" shall include both complete hydrolysis and partial hydrolysis.

The phenyl-modified hybrid prepolymer (B) is composed of at least one of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and its hydrolyzate, and phenyltrialkoxysilane and its hydrolyzate. It is a phenyl-modified hybrid prepolymer produced by hydrolyzing and condensing at least one of them with at least one of diphenyldialkoxysilane and its hydrolyzate.

The linear polysiloxane (D) is a linear polysiloxane having a triethoxysilyl group at both ends.

The linear polysiloxane (E) is a linear polysiloxane having a trimethoxysilyl group at both ends.

In addition, the kit for a phenyl-modified organopolysiloxane prepolymer composition according to the present invention comprises a main agent (C) containing phenyl-modified hybrid prepolymers (A) and (B), a linear polysiloxane (D), and a linear polysiloxane (D). It includes a curing agent (F) containing (E).

By doing so, the phenyl-modified organopolysiloxane polymer that can be used at 200 ° C. or higher can be obtained at a relatively low temperature of 200 ° C. or lower, 180 ° C. or lower, and further 150 ° C. or lower depending on the compounding conditions of the prepolymer composition. It can be obtained by heat treatment for a short time. The cured phenyl-modified organopolysiloxane polymer can exhibit heat resistance that can be used continuously at 200 ° C or higher, and in particular, high temperature such as SiC power module encapsulant, ECU insulation / bonding member that requires high temperature operation. It can be used as an elastic material for parts that require operation.

Further, the phenyl-modified organopolysiloxane prepolymer may be mixed with a filler for the purpose of imparting thermal conductivity, conductivity, insulating property, etc., but the presence of fine powder of several μm or less used at that time. May cause poor curing. Although the reason is not clear, the phenyl-modified organopolysiloxane prepolymer may cause curing delay or curing failure in carbon black, alumina fine particles, etc. due to differences in surface characteristics and specific surface area. Even in such a case, if the curing accelerating component is used in the prepolymer composition of the present invention, the curing accelerating effect can be exhibited and the curing conditions can be relaxed.

It is a figure which shows the mass reduction rate when the sheet of Example 14 and Comparative Examples 9 and 10 was stored in the warm air circulation type dryer of 200 degreeC.

The present invention will be described in detail below. The phenyl-modified organopolysiloxane prepolymer composition according to the present invention comprises at least a main agent (C) containing phenyl-modified hybrid prepolymers (A) and (B), and linear polysiloxanes (D) and (E). It is made by mixing with a curing agent (F) containing.

1. 1. Main agent (C)
The main agent (C) contains phenyl-modified hybrid prepolymers (A) and (B). The phenyl-modified hybrid prepolymer (A) is produced by subjecting polydimethylsiloxane (PDMS-1) having a silanol group at both ends to a condensation reaction with at least one of phenyltrialkoxysilane and its hydrolyzate. Phenyl-modified hybrid prepolymer. The phenyl-modified hybrid prepolymer (B) is composed of at least one of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and its hydrolyzate, and phenyltrialkoxysilane and its hydrolyzate. It is a phenyl-modified hybrid prepolymer produced by hydrolyzing and condensing at least one of them with at least one of diphenyldialkoxysilane and its hydrolyzate. Hereinafter, the raw materials and production methods of the phenyl-modified hybrid prepolymers (A) and (B) will be described.

<Polydimethylsiloxane (PDMS-1) having silanol groups at both ends>
The polydimethylsiloxane (PDMS) which is a raw material of the phenyl-modified hybrid prepolymer (A) is a polydimethylsiloxane (PDMS-1) having a silanol group at both ends, and is represented by the general formula (1). Is preferable.

The polydimethylsiloxane (PDMS-1) having silanol groups at both ends used in the raw material of the present invention is a homogeneous one having a narrow molecular weight distribution produced by living anionic polymerization or the like using alkyllithium as an initiator. It is preferable to have. The molecular weight distribution index (Mw / Mn) calculated by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 1.3 or less, more preferably 1.2 or less, still more preferably. 1.1 or less. When the molecular weight distribution index (Mw / Mn) of polydimethylsiloxane (PDMS-1) having silanol groups at both ends is 1.3 or less, the phenyl modification reaction is likely to proceed and there is no risk of curing failure. Further, a phenyl-modified organoin obtained by mixing a phenyl-modified hybrid prepolymer (A) and a phenyl-modified hybrid prepolymer (B) described later, further adding a curing agent (F) to the main agent (C) which is a mixture, and heating and curing the mixture. The cured polysiloxane polymer (gel) can maintain heat resistance for a long period of time. Further, when the molecular weight distribution index (Mw / Mn) of polydimethylsiloxane (PDMS-1) having silanol groups at both ends is 1.2 or less, and further 1.1 or less, heat resistance at a high temperature of 200 ° C. or higher is obtained. A cured phenyl-modified organopolysiloxane polymer (gel) having particularly excellent maintenance properties can be obtained. When this molecular weight distribution index (Mw / Mn) is larger than 1.3, the ratio of low molecular weight components and high molecular weight components is high, and the phenyl denaturation reaction does not proceed easily, or the unreacted components increase during curing, resulting in poor curing. There is a risk and it may not be preferable for use in an environment where heat resistance to which the present invention is applied is required.

Further, the number average molecular weight (Mn) of polydimethylsiloxane (PDMS-1), which is a raw material of the phenyl-modified hybrid prepolymer (A), is preferably 18,000 to 60,000. When the number average molecular weight (Mn) is 18,000 or more, the heat resistance of the cured product can be enhanced and the adhesiveness can be exhibited. Further, when the number average molecular weight is 60,000 or less, polydimethylsiloxane (PDMS-1) and phenyl-modified hybrid prepolymer (A) can be easily synthesized. If the number average molecular weight (Mn) is less than 18,000, the heat resistance of the cured product may be lowered and the adhesiveness may be difficult to develop. On the contrary, if it exceeds 60,000, polydimethylsiloxane (PDMS-1) ) And the phenyl-modified hybrid prepolymer (A) may be difficult to synthesize. Considering the heat resistance maintenance property, adhesiveness, viscosity, ease of synthesis, etc., the more preferable number average molecular weight is about 20,000 to 48,000, and more preferably 25,000 to 45,000, which is the most. It is preferably 30,000 to 40,000. m is an integer satisfying the condition.

When heat resistance and flexibility are particularly desired, for example, when a gel-like substance used at a high temperature of 250 ° C. or higher due to the operation of a power semiconductor such as SiC is desired, the number average molecular weight (Mn) is 30. More than 000 polydimethylsiloxane (PDMS) is required. However, in general, when the molecular weight is increased, the molecular weight distribution index becomes large, so that the synthesis conditions such as the temperature uniformity in the reaction vessel for producing polydimethylsiloxane (PDMS) and the homogeneity of stirring become strict.

As the polydimethylsiloxane (PDMS-1) having a silanol group at both ends synthesized by living anionic polymerization, FM9926 (Mn = 18,000 to 23,000, Mw / Mn = 1.05) manufactured by JNC Co., Ltd. ~ 1.18), FM9927 (Mn = 29,000 ~ 37,000, Mw / Mn = 1.06 ~ 1.25), FM9928 (Mn = 45,000 ~ 48,000, Mw / Mn = 1.10) ~ 1.35) and the like. FM9927 is particularly preferable for applications at high temperatures of 250 ° C. or higher. Regarding Mn and Mw / Mn of FM9926, FM9927 and FM9928, there are generally lot-to-lot variations in the above range, but the variation within this range results in the phenyl-modified hybrid prepolymer (A) and further phenyl-modified organopoly. There is no significant difference in the physical properties of the cured siloxane polymer.

<Polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends>
The polydimethylsiloxane (PDMS) which is a raw material of the phenyl-modified hybrid prepolymer (B) is a polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and is represented by the general formula (2). Is preferable.

Here, R ¹ is an alkyl group having 1 to 3 carbon atoms and is selected from a methyl group, an ethyl group, an n-propyl group and an isopropyl group, but even if they are all the same, they are partially or all different. May be. R ¹ is most preferably an ethyl group from the viewpoint of reactivity, safety and reaction control. X is oxygen or an alkylene group having 2 or less carbon atoms, and may be the same or different.

By having trialkoxysilyl groups at both ends, it is possible to increase the number of reaction points with diphenyldialkoxysilane or its partial hydrolyzate or condensate, which is inferior in reactivity due to steric hindrance, and to increase the desired condensation reaction rate. .. As for this raw material, it is desirable that the molecular weight distribution is narrow as in the case of polydimethylsiloxane (PDMS-1) having silanol groups at both ends. This type of polydimethylsiloxane (PDMS), which has a narrow molecular weight distribution, can also be synthesized by the application of living anionic polymerization. For polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends, the molecular weight distribution index (Mw / Mn) is preferably 1.3 or less, more preferably 1.2 or less, still more preferably. Use 1.1 or less. If the molecular weight distribution index (Mw / Mn) of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends is 1.3 or less, and further 1.2 or less, the phenyl modification reaction is likely to proceed and curing is possible. There is no risk of failure. Further, the finally obtained phenyl-modified organopolysiloxane polymer cured product (gel body) can maintain heat resistance for a long period of time. Further, when the molecular weight distribution index (Mw / Mn) of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends is 1.1 or less, the heat resistance maintenance property at a high temperature of 200 ° C. or higher is particularly excellent. A cured product (gel body) is obtained. When this molecular weight distribution index (Mw / Mn) is larger than 1.3, the ratio of low molecular weight components and high molecular weight components is high, and the phenyl denaturation reaction does not proceed easily, or the unreacted components increase during curing, resulting in poor curing. There is a risk. At the time of the reaction, a silanol group may be produced by hydrolyzing a part or all of the alkoxy group of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends.

Further, the number average molecular weight (Mn) of polydimethylsiloxane (PDMS-2), which is a raw material of the phenyl-modified hybrid prepolymer (B), is preferably 2,500 to 30,000. When the number average molecular weight (Mn) is 2,500 or more, the heat resistance of the finally obtained cured product can be enhanced, the shrinkage of the cured product can be suppressed, and molding can be facilitated. Further, when the number average molecular weight (Mn) is 30,000 or less, the hardness can be increased and the adhesiveness can be suppressed. If the number average molecular weight (Mn) is less than 2,500, the heat resistance of the cured product is lowered and the shrinkage of the cured product is large, which may make molding difficult. On the contrary, if it exceeds 30,000, the phenyl-modified hybrid prepolymer (B) also has adhesiveness due to the low hardness peculiar to the polymer, and there is a possibility that the adhesiveness of the cured phenyl-modified organopolysiloxane polymer cannot be controlled. Considering the heat resistance maintenance property, shrinkage rate, adhesiveness, etc., the more preferable number average molecular weight is about 5,000 to 28,000, more preferably 10,000 to 25,000, and most preferably 16, It is 000 to 24,000. n is an integer satisfying the condition.

As the polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends synthesized by the living anion polymerization method, FM8813 (Mn = 2,700 to 3,300, Mw / Mn =) manufactured by JNC Co., Ltd. 1.05 to 1.15), FM8821 (Mn = 5,400 to 6,600, Mw / Mn = 1.05 to 1.16), FM8825 (Mn = 10,000 to 14,000, Mw / Mn = 1.05 to 1.18), FM8826 (Mn = 16,000 to 24,000, Mw / Mn = 1.05 to 1.18) and the like. FM8826 is particularly preferable for applications at high temperatures of 250 ° C. or higher. Regarding Mn and Mw / Mn of FM8813, FM8821, FM8825, and FM8826, there are generally lot-to-lot variations in the above range, but the variations within this range result in the obtained phenyl-modified hybrid prepolymer (B) and further phenyl-modified. There is no significant difference in the physical properties of the cured organopolysiloxane polymer.

<Phenylalkoxysilane>
The phenylalkoxysilane used as a raw material for phenyl modification in the present invention is an alkoxysilane having one or two phenyl groups in the molecule, and a silanol group is generated by hydrolysis of the alkoxy group to remove it. Condenses with polydimethylsiloxane (PDMS) or modified polydimethylsiloxane (PDMS) by alcohol or dehydration reaction. Although there are no restrictions on the alkoxy group, those having 1 to 3 carbon atoms are generally used, and a methoxy group and an ethoxy group are particularly preferable.

Phenyltrialkoxysilane has one phenyl group in the molecule, and it is desirable to use highly reactive phenyltrimethoxysilane from the viewpoint of reactivity, but from the viewpoint of stability and safety (generation of methanol). It is desirable to use phenyltriethoxysilane having an ethoxy group (avoid). Of course, if there is no problem in the exhaust environment or the like, phenyltrimethoxysilane may be used.

On the other hand, the diphenyldialkoxysilane having two phenyl groups in the molecule used for the preparation of the phenyl-modified hybrid prepolymer (B) generally has low reactivity, and it is better to use the diphenyldimethoxysilane having a methoxy group. , Diphenyldiethoxysilane is preferable because it is less susceptible to steric hindrance due to the phenyl group and has excellent reactivity. Although it is possible to use diphenyldiethoxysilane, it is preferable to use diphenyldimethoxysilane, which has higher reactivity, although there is a problem in safety because the reactivity is extremely poor due to steric hindrance and the like. Although it is not generally sold and difficult to obtain, the same effect or more can be obtained by using a diphenyldialkoxysilane oligomer.

<Phenyl-modified hybrid prepolymers (A) and (B)>
[Manufacturing of phenyl-modified hybrid prepolymer]
In the present invention, the phenyl-modified hybrid prepolymers (A) and (B) are the condensation reaction of PDMS-1 and phenyltrialkoxysilane, respectively, and the partial or partial of PDMS-2, phenyltrialkoxysilane and diphenyldialkoxysilane. Prepared by complete hydrolysis / condensation reaction. An organometallic catalyst or a metal alkoxide-based catalyst is usually used for the condensation reaction. As the organometallic catalyst, an organotin compound such as dibutyltin dilaurate or dibutyltin di-2-ethylhexoate or an organometallic compound of bismuth, zinc or zirconium is often used. Further, an organic metal alkoxide condensation catalyst such as an organic titanium compound such as tetra (2-ethylhexyl) titanate, an acid catalyst such as hydrochloric acid, an alkaline catalyst such as ammonia may be used for the purpose of hydrolysis. However, in a heat-resistant environment, particularly in a usage environment of 250 ° C. or higher, many organometallic catalysts may be negative catalysts, and tend to exhibit effects such as cleavage of the polymer molecular skeleton that deteriorate the heat-resistant properties. Therefore, it is difficult to easily use the above catalyst as a catalyst for synthesizing a hybrid prepolymer or obtaining a cured product from the hybrid prepolymer.

However, when Ti-based alkoxides are used, they are superior in terms of heat resistance because they do not exhibit the catalytic effect of accelerating thermal deterioration as described above after curing. In addition, a Zr-based catalyst or an Al-based catalyst can also be used.

It is preferable to use a titanium alkoxide compound as a catalyst for the reaction between polydimethylsiloxane (PDMS-1) having a silanol group at both ends and phenyltrialkoxysilane. Although it is possible to use the organometallic compound, a Ti-based catalyst having a low negative catalytic effect is desirable in consideration of heat-resistant applications. As Ti-based (Ti alkoxides) catalysts, tetra (2-ethylhexyl) titanate, titanium tetra n-butoxide, titanium tetraisopropoxide, titanium diisopropoxybis (ethylacetacetate), titanium tetraacetylacetonate, titanium di- Examples thereof include 2-ethylhexoxybis (2-ethyl-3-hydroxyhexoxide) and titanium diisopropoxybis (acetylacetonate). When a Ti-based catalyst is used, it tends to be colored yellow or tan during the reaction. When applied to products, it is preferable to use tetra (2-ethylhexyl) titanate, which is particularly difficult to develop color, because yellowish colors are easily avoided as deteriorated colors.

As the titanium alkoxides, it is preferable to use 0.08 to 0.2 mol with respect to 1 mol of polydimethylsiloxane (PDMS-1) having a silanol group at both ends. If it is less than 0.08 mol, it may not be cured, and if it exceeds 0.2 mol, the effect does not change. The amount of titanium alkoxide added is more preferably 0.09 to 0.15 mol with respect to 1 mol of polydimethylsiloxane (PDMS-1) having a silanol group at both ends.

Similarly, in the reaction of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends, phenyltrialkoxysilane and diphenyldialkoxysilane, it is preferable to use a titanium alkoxide compound as a catalyst. Although it is possible to use the organometallic compound, a Ti-based catalyst having a low negative catalytic effect is desirable in consideration of heat-resistant applications as described above. Examples of the Ti-based (Ti alkoxides) catalyst include the same catalysts as described above, and it is preferable to use tetra (2-ethylhexyl) titanate for the same reasons as described above.

As the titanium alkoxides, it is preferable to use 0.08 to 0.2 mol with respect to 1 mol of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends. If it is less than 0.08 mol, it may not be cured, and if it exceeds 0.2 mol, the effect does not change. The amount of titanium alkoxide added is more preferably 0.09 to 0.15 mol with respect to 1 mol of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends.

When the above condensation reaction is carried out, it is placed in a container used for the reaction in order to carry out a stable hydrolysis, dehydration and dealcoholization reaction of polydimethylsiloxane (PDMS), phenyltriethoxysilane, diphenyldialkoxysilane and the like. It is desirable to have an atmosphere filled with inert gas. Examples of the inert gas include Nitrogen gas and Group 18 elements (helium, neon, argon, krypton, xenon, etc.) which are rare gases. Further, these gases may be mixed and used. As a method of hydrolysis, various methods such as dropping an appropriate amount of water, spraying, and introducing water vapor can be considered. The amount of water to be introduced may be appropriately adjusted in consideration of the difference in reactivity depending on the type of alkoxysilane monomer used. The alkoxy group of the hydrolyzed phenylalkoxysilane or diphenyldialkoxysilane becomes a silanol group, and by heating in the presence of an inert gas, both polydimethylsiloxane (PDMS) together with a partially remaining alkoxy group. Causes a condensation reaction with a terminal silanol group or alkoxysilyl group. For example, the condensation reaction of polydimethylsiloxane (PDMS) having a sufficiently small molecular weight distribution index (Mw / Mn) with alkoxysilane having a phenyl group stabilizes the reaction temperature and the water content in the atmosphere of the inert gas. This allows for rapid completion at relatively low temperatures. In order to further stabilize the reaction, it is also desirable to attach a reflux tube or the like at the initial stage of synthesis and allow the reaction to react for a certain period of time.

[Mixing ratio]
The compounding ratio of polydimethylsiloxane (PDMS-1) having a silanol group at both ends and phenyltrialkoxysilane (Ph-1) was 0.5 for (Ph-1) with respect to 1 mol of (PDMS-1). The molar ratio is preferably ~ 5 mol. When the molar ratio is in the above range, the condensation reaction is smoothly carried out, and when (Ph-1) is large, the flexibility may be impaired. On the contrary, when the amount of (Ph-1) is small, the heat resistance retention property is deteriorated and it becomes difficult to cure in the end. The compounding ratio is more preferably 1 to 4 mol of (Ph-1) with respect to 1 mol of (PDMS-1).

The compounding ratio of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends with phenyltrialkoxysilane (Ph-1) and diphenyldialkoxysilane (Ph-2) is (PDMS-2). ) It is preferable that (Ph-1) has a molar ratio of 0.5 to 3 mol and (Ph-2) has a molar ratio of 0.5 to 3 mol with respect to 1 mol. When the molar ratio is in the above range, the condensation reaction is smoothly carried out, and when (Ph-1) and (Ph-2) are large, the flexibility may be impaired. On the contrary, when the amount of (Ph-1) and (Ph-2) is small, the heat resistance retention property is deteriorated and finally it becomes difficult to cure. The compounding ratio is more preferably 1 to 2 mol for (Ph-1) and 1 to 2 mol for (Ph-2) with respect to 1 mol of (PDMS-2).

The molecular ratio referred to here is the number of polydimethylsiloxane (PDMS) (PDMS-1 and PDMS-2) measured by gel permeation chromatography (GPC method) using polystyrene as a standard substance and tetrahydrofuran as an eluent. It is a molar ratio calculated based on the average molecular weight (Mn) and the molecular weights of phenyltrialkoxysilane (Ph-1) and diphenyldialkoxysilane (Ph-2).

[Method for preparing phenyl-modified hybrid prepolymers (A) and (B)]
For the preparation (synthesis) of the phenyl-modified hybrid prepolymers (A) and (B), a reaction vessel (flask having a plurality of insertion ports) equipped with a stirrer, a thermometer, and a dropping line is used. For more precise synthesis, it is also desirable to accompany a reflux device. The stirrer is particularly limited as long as it has the effect of uniformly mixing high-viscosity liquid raw materials that contribute to the reaction, such as a rotary stirrer with stirring blades, a magnetic stirrer, a biaxial planetary stirrer, and an ultrasonic cleaner. There is no. However, a rotary stirrer, a magnetic stirrer, or the like is desirable because it is accompanied by temperature control, atmosphere control, component dropping line, and the like. Uniformity is important for the synthesis temperature, and if the synthesis capacity is small, a simple method such as a hot plate is sufficient, but in mass production lines that exceed 5 L, heat retention and homogeneity such as mantle heaters are high. A heating method is desirable. The synthesis temperature is appropriately set between 60 and 100 ° C. It is set individually according to the type of raw material, compounding ratio, synthesis equipment, etc., such as when reacting at low temperature for a long period of time or when synthesizing at high temperature for a short time. For the synthetic atmosphere, for example, nitrogen gas is used as the inert gas, and the reaction vessel is sufficiently filled with nitrogen gas having a constant water content. At this time, it is desirable to use a nitrogen gas producing apparatus for the nitrogen gas. Of course, it is possible to supply nitrogen from a cylinder or liquid nitrogen, but it may take a long time to synthesize, so it is desirable to use a manufacturing device with little fluctuation in supply pressure.

In the phenyl-modified hybrid prepolymers (A) and (B), the phenyl-modified hybrid prepolymer containing a certain structural unit shall include a phenyl-modified hybrid prepolymer in which a plurality of certain structural units are condensed with dehydration or dealcoholization. .. Metals such as Ti derived from the condensation catalyst may be incorporated into the molecular structure, but may not be incorporated.

By mixing the phenyl-modified hybrid prepolymer (A) and the phenyl-modified hybrid prepolymer (B) in an arbitrary ratio, the main agent (C), which is a phenyl-modified hybrid prepolymer mixture, can be prepared. The mixing method is not limited, but a device that is not easily affected by the outside air, such as a biaxial planetary agitator, is desirable. The main agent (C), which is the obtained phenyl-modified hybrid prepolymer mixture, becomes a cured product through a heating step. There are no restrictions on the heating method, such as an electric furnace such as a blower type or a circulation type, or an atmosphere furnace.

2. 2. Hardener (F)
The curing agent (F) contains linear polysiloxanes (D) and (E). The linear polysiloxane (D) is a linear polysiloxane having a triethoxysilyl group at both ends. The linear polysiloxane (E) is a linear polysiloxane having a trimethoxysilyl group at both ends. Hereinafter, the raw materials and production methods of the linear polysiloxanes (D) and (E) will be described.

The linear polysiloxane (E) has high reactivity due to the rapid hydrolysis of the methoxy group, and can accelerate the curing of the condensed phenyl-modified organopolysilokipresan polymer composition. However, due to its high reactivity, the surface that easily comes into contact with moisture cures quickly, and if the film thickness is 1 mm or more, the inside blocked by the curing of the surface layer is poorly cured, or bubbles due to the volatile components of alcohol and moisture generated by condensation are generated. There is a problem that it is included. Therefore, it is difficult to use it alone for curing thick films and molded products.

On the other hand, the linear polysiloxane (D) is not so highly reactive and reacts relatively slowly, so that it is suitable for curing a thick film, but the curing catalytic action is the linear polysiloxane (E). ) Not as expensive. There are many problems to use each independently. Therefore, these are appropriately mixed and used according to the purpose.

<Linear polysiloxane having a triethoxysilyl group or a trimethoxysilyl group at both ends>
The linear polysiloxane (D) and the linear polysiloxane (E) used as the curing agent component of the present invention have a curing rate due to the action of the hydrolyzable triethoxysilyl group and the trimethoxysilyl group at both ends. It can speed up and improve the adhesiveness with various bonding materials. Examples of the linear polysiloxane (D) include polydimethylsiloxane having a triethoxysilyl group at both ends. This may be the same as PDMS-2. Moreover, as a linear polysiloxane (E), polydimethylsiloxane having a trimethoxysilyl group at both ends is exemplified. The number average molecular weight (Mn) of the linear polysiloxanes (D) and (E) is preferably in the range of 2,500 to 25,000.

Although it is possible to produce the phenyl-modified organopolysiloxane polymer of the present invention even if the number average molecular weight (Mn) of the above (D) and (E) is less than 2,500, the polymer of the present invention can be produced. The number average molecular weight (Mn) is preferably 2,500 or more, preferably 5,000, in order to satisfy the heat resistance (maintenance) characteristics of 200 ° C by itself or 250 ° C when a filler is blended and the resistance to cold shock. The above is more preferable. Further, when the number average molecular weight (Mn) of (D) and (E) exceeds 25,000, the number of trialkoxysilyl groups is extremely reduced (when the masses used are the same, the number of moles of functional groups is increased. (Reduces), it becomes difficult to develop the function as a curing component, it is difficult to control the molecular weight at the time of production, and the viscosity becomes high, which makes it difficult to use.

<Polydimethylsiloxane having a triethoxysilyl group at both ends>
The linear polysiloxane (D) contained in the curing agent (F) used in the present invention is a polydimethylsiloxane having triethoxysilyl groups at both ends represented by the general formula (3). Is preferable.

(C ₂ H ₅ O) ₃ Si-CH ₂ CH _2- (Si (CH ₃ ) ₂ -O) _p -Si (CH ₃ ) ₂ -CH ₂ CH ₂ -Si (OC ₂ H ₅ ) ₃ ... (3)

Here, the number average molecular weight (Mn) of the compound represented by the general formula (3) is preferably 2,500 to 25,000, more preferably 5,000 to 25,000, and phenyl modification. Considering the heat resistance of the organopolysiloxane polymer and its function as a curing promoting component, it is more preferably 10,000 to 24,000. It can be used properly depending on the application, and it is desirable to use a high molecular weight one when flexibility is required and a low molecular weight one when releasability and strength are required. p is an integer that satisfies the condition. It is desirable that this raw material also has a narrow molecular weight distribution for the same reason as polydimethylsiloxane (PDMS-2). This raw material having a narrow molecular weight distribution can also be synthesized by applying living anionic polymerization, and the molecular weight distribution index (Mw / Mn) is preferably 1.3 or less, more preferably 1.2 or less. More preferably, 1.1 or less is used.

The polydimethylsiloxane represented by the general formula (3) having a triethoxysilyl group at both ends having a number average molecular weight (Mn) of 2,500 to 25,000 synthesized by the living anion polymerization method is JNC. FM8813 (Mn = 2,700 to 3,300, Mw / Mn = 1.05 to 1.15), FM8821 (Mn = 5,400 to 6,600, Mw / Mn = 1.05 to 1.15) manufactured by FM8813 Co., Ltd. 16), FM8825 (Mn = 10,000 to 14,000, Mw / Mn = 1.05 to 1.18), FM8826 (Mn = 16,000 to 24,000, Mw / Mn = 1.05 to 1.18). 18) and the like. In particular, FM8826 is preferable when it is used continuously for a long time at a high temperature of 200 ° C. or higher. Regarding Mn and Mw / Mn of FM8813, FM8821, FM8825, and FM8826, there are variations between lots in the above range, but the variations within this range greatly affect the physical properties of the obtained phenyl-modified organopolysiloxane polymer cured product. It doesn't make a difference.

<Polydimethylsiloxane having a trimethoxysilyl group at both ends>
The linear polysiloxane (E) contained in the curing agent (F) used in the present invention is a polydimethylsiloxane having a trimethoxysilyl group at both ends represented by the general formula (4). Is preferable.

(CH ₃ O) ₃ Si-CH ₂ CH _2- (Si (CH ₃ ) ₂ -O) _q -Si (CH ₃ ) ₂ -CH ₂ CH ₂ -Si (OCH ₃ ) ₃ ... (4)

Here, the number average molecular weight (Mn) of the compound represented by the general formula (4) is preferably 2,500 to 25,000, more preferably 5,000 to 25,000, and phenyl modification. Considering the heat resistance of the organopolysiloxane polymer and its function as a curing promoting component, it is more preferably 10,000 to 24,000. Similar to the compound represented by the general formula (3), it can be used properly depending on the application. If flexibility is required, a high molecular weight compound is used, and if releasability and strength are required, a low molecular weight compound is used. It is desirable to use. q is an integer that satisfies the condition. It is desirable that this raw material also has a narrow molecular weight distribution for the same reason as polydimethylsiloxane (PDMS-2). This raw material having a narrow molecular weight distribution can also be synthesized by applying living anionic polymerization, and the molecular weight distribution index (Mw / Mn) is preferably 1.3 or less, more preferably 1.2 or less. More preferably, 1.1 or less is used.

The polydimethylsiloxane represented by the general formula (4) having a trimethoxysilyl group at both ends having a number average molecular weight (Mn) of 2,500 to 25,000 synthesized by the living anion polymerization method is JNC. XP1428 (Mn = 2,700 to 3,300, Mw / Mn = 1.05 to 1.15), XP1429 (Mn = 5,400 to 6,600, Mw / Mn = 1.05 to 1.15) manufactured by Co., Ltd. 16), XP1430 (Mn = 10,000 to 14,000, Mw / Mn = 1.05 to 1.18), XP1421 (Mn = 16,000 to 24,000, Mw / Mn = 1.05 to 1.18). 18) and the like. In particular, XP1421 is preferable when it is used continuously for a long time at a high temperature of 200 ° C. or higher. Regarding Mn and Mw / Mn of XP1428, XP1429, XP1430, and XP1421, there are variations between lots in the above range, but the variations within this range greatly affect the physical properties of the obtained phenyl-modified organopolysiloxane polymer cured product. It doesn't make a difference.

3. 3. Preparation of Phenyl-Modified Organopolysiloxane Prepolymer Composition The linear polysiloxane (D) and (E) are the main agent (C) which is a mixture of the phenyl-modified hybrid prepolymer (A) and the phenyl-modified hybrid prepolymer (B). Easily reacts with and by heating and condenses by dealcoholization (or dehydration). This reaction is faster with polydimethylsiloxane having methoxysilyl groups at both ends, but when the film thickness of the phenyl-modified hybrid prepolymer mixture, which is the object to be cured, is 1 mm or more, the surface cures quickly and a film is formed. , There is a risk of internal curing failure. Therefore, in the present invention, the curing rate is controlled by appropriately mixing with polydimethylsiloxane having a triethoxysilyl group at both ends, which promotes curing relatively mildly.

The blending ratio of the linear polysiloxane (D) and the linear polysiloxane (E) is preferably (D) / (E) = 0.1 to 6 in terms of mass ratio, and may be within this range. If so, a sufficient curing promoting effect is recognized. For general purposes, a mixture of the same amount (D) / (E) with a mass ratio of 1 is preferable, but it can be used properly when a relatively thin film requires post-curing film strength or when flexibility is required. desirable. If it is a thick film, it is desirable to use a large amount of linear polysiloxane (D), and if it is a thin film and the purpose is to shorten the curing time, it is desirable to use a large amount of linear polysiloxane (E). The compounding ratio of (D) and (E) is more preferably (D) / (E) = 0.3 to 4 in terms of mass ratio.

4. Catalyst In the present invention, a metal compound catalyst can be used in combination with the curing agent (F) for the purpose of further promoting curing. A Zn, Sn, Zr, Bi, Pt-based compound catalyst is used as an effective catalyst for promoting the condensation reaction of the polysiloxane prepolymer. Further, in recent years, a curing catalyst using In, Hf, or the like has also been proposed. However, many of these metal compound catalysts exhibit a negative catalytic effect when the polysiloxane polymer cured product produced after thermosetting is used in a high temperature environment, and accelerate the thermal deterioration of the polymer. Therefore, when using it, it is essential to use it at a low concentration where the negative catalytic effect does not appear. In the present invention, when a metal compound is used, a Sn catalyst that does not easily cause thermal deterioration is used at an extremely low concentration. The amount of the Sn-based compound used as the curing catalyst is preferably 0.03% by mass or less of the heat-cured product of the phenyl-modified organopolysiloxane polymer composition.

Examples of Sn-based catalysts include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin bisacetylacetonate, dibutyltin bisethylhexanoate, dibutyltin dioctate, dibutyltin oxide, and dioctyltin oxide. In the present invention, it is preferable to use dibutyltin dilaurate mainly from the viewpoint of availability and ease of use.

5. Blending ratio of main agent (C) and curing agent (F) In the phenyl-modified organopolysiloxane prepolymer composition of the present invention, the blending ratio of the main agent (C) and the curing agent (F) is (C) by mass ratio. ): (F) = 98: 2 to 75:25 is preferable. If the amount of the curing agent (F) is less than 2% by mass, the curing rate may be insufficient, and if it exceeds 25% by mass, the heat resistance (maintenance) and flexibility of the produced phenyl-modified organopolysiloxane polymer cured product are inadequate. May be sufficient. Considering the curing rate, heat resistance (maintenance), flexibility, etc., the mixing ratio is more preferably (C) :( F) = 97: 3 to 80:20 in terms of mass ratio.

6. Measurement of Average Molecular Weight The average molecular weight of the polysiloxane-based raw material used as the raw material for the main agent (C) and the curing agent (F) in the prepolymer composition of the present invention is measured by a gel permeation chromatograph (GPC) method. The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is defined as the molecular weight distribution index (Mw / Mn). Polystyrene is used as a standard sample, and the polystyrene-equivalent molecular weight is measured.

The polystyrene-equivalent molecular weight measurement by the GPC method is performed under the following measurement conditions.
a) Measuring equipment: Tosoh GPC HLC-8320PC
b) Columns with Mn 30,000 or less: TSKgel guardColumn Super HZ-H, TSKgel Super HZM-H x 2 c) Columns with Mn 30,000 or more: TSKgel guardColum Super MP (HZ) -N, TSKgelH Book d) Oven temperature: 40 ° C
e) Eluent: Tetrahydrofuran (THF) 1.0 mL / min
f) Standard sample: Polystyrene g) Injection amount: 100 μL
h) Concentration: 0.05g / 10mL
i) Sample preparation: Dissolve by stirring at room temperature using THF containing 0.2% by mass of 2,6-di-tert-butyl-p-phenol (BHT) as a solvent.
j) Correction: The molecular weight is calculated by correcting the deviation of the BHT peak between the time of calibration curve measurement and the time of sample measurement.

7. Encapsulating Material The main use of the phenyl-modified organopolysiloxane prepolymer composition of the present invention is an encapsulating material called a potting material. In recent years, high heat resistance of potting materials has been required due to high integration and development of SiC power modules. In particular, thermal stress between constituent members generated when the environmental temperature changes from high temperature use to normal temperature due to power off or low temperature environment is a problem.

The organopolysiloxane polymer cured product obtained by curing the organopolysiloxane prepolymer is an elastic material having high heat resistance, has a constant linear expansion coefficient from -60 to 300 ° C., and is excellent in thermal stress relaxation.

When the curing temperature of this potting material is high, various problems occur due to the influence of linear expansion of various constituent materials. For example, the solder joint surface may come off, or the joint surface between the package and the terminal may come off. Therefore, a curing accelerating compound that can be cured at a low temperature during heat curing and has high heat resistance is useful.

The phenyl-modified organopolysiloxane polymer of the present invention is obtained by using any of the above phenyl-modified organopolysiloxane prepolymer compositions at a relatively low temperature of 200 ° C. or lower, 180 ° C. or lower depending on the compounding conditions, and further at a relatively low temperature of 150 ° C. or lower. It can be obtained by heat treatment for hours. The cured phenyl-modified organopolysiloxane polymer can exhibit heat resistance that can be used continuously at 200 ° C or higher, and in particular, high temperature such as SiC power module encapsulant, ECU insulation / bonding member that requires high temperature operation. It can be used as an elastic material for parts that require operation.

8. Heat-dissipating sheet As described above, in a heat-conductive elastic sheet containing a heat-conductive filler called a heat-dissipating sheet, curing inhibition may occur depending on the heat-conductive filler used, which may significantly worsen the curing conditions. As the heat radiating sheet has become highly integrated and thinned in recent years, the demand for heat resistance is increasing, and it is not possible to use a general-purpose curing agent such as a silane coupling agent that impairs heat resistance.

Further, in the heat radiating sheet, it is common to use a plurality of types of thermally conductive fillers having different particle diameters. In order to realize close packing, it is known to combine fine particles having a large particle diameter of several tens of μm and several μm with fine particles on the order of μm or less. Curing inhibition becomes remarkable depending on the fine particles of μm or less used at that time.

In the case of curing inhibition, it is presumed that the reactive group of the phenyl-modified organopolysiloxane prepolymer reacts with the functional group on the surface of the fine particle filler, and the phenyl-modified organopolysiloxane prepolymer is unlikely to cause a condensation reaction. Correlation such as surface area of fine particles, type of surface functional group, shape, etc. is not clear. Due to characteristics such as flexibility and conductivity, it is often difficult to replace the selected fine particle filler with another filler. In particular, in the heat dissipation sheet, the fine particles that can maintain the flexibility may be limited, and there are some that greatly extend the curing time by blending such a filler. In such a case, the linear polysiloxanes (D) and (E) used as components of the curing agent (F) of the present invention are very useful and effective as curing promoting components.

9. Kit for phenyl-modified organopolysiloxane prepolymer composition Curing containing the main agent (C) containing the above-mentioned phenyl-modified hybrid prepolymers (A) and (B) and the above-mentioned linear polysiloxanes (D) and (E). With the agent (F), a kit for a phenyl-modified organopolysiloxane prepolymer composition can be constructed.

The present invention can be summarized as follows.

(1) The phenyl-modified organopolysiloxane prepolymer composition according to the present invention comprises at least the main agent (C) containing the phenyl-modified hybrid prepolymers (A) and (B), the linear polysiloxane (D) and the linear polysiloxane (D). It is made by mixing with a curing agent (F) containing (E).

The phenyl-modified hybrid prepolymer (A) is produced by subjecting polydimethylsiloxane (PDMS-1) having a silanol group at both ends to a condensation reaction with at least one of phenyltrialkoxysilane and its hydrolyzate. Phenyl-modified hybrid prepolymer.

The phenyl-modified hybrid prepolymer (B) is composed of at least one of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and its hydrolyzate, and phenyltrialkoxysilane and its hydrolyzate. It is a phenyl-modified hybrid prepolymer produced by hydrolyzing and condensing at least one of them with at least one of diphenyldialkoxysilane and its hydrolyzate.

The linear polysiloxane (D) is a linear polysiloxane having a triethoxysilyl group at both ends.

The linear polysiloxane (E) is a linear polysiloxane having a trimethoxysilyl group at both ends.

(2) In the phenyl-modified organopolysiloxane prepolymer composition of the above (1) according to the present invention, the number average molecular weight (Mn) of the linear polysiloxane (D) is 2,500 to 25,000. , The number average molecular weight (Mn) of the linear polysiloxane (E) is preferably 2,500 to 25,000.

(3) The phenyl-modified organopolysiloxane prepolymer composition according to the above (1) or (2) according to the present invention has a blending ratio of the linear polysiloxane (D) and the linear polysiloxane (E). The mass ratio is preferably (D) / (E) = 0.1 to 6.

(4) In the phenyl-modified organopolysiloxane prepolymer composition according to any one of (1) to (3) above according to the present invention, the curing agent (F) contains an organic tin compound and contains an organic tin compound. The amount is preferably 0.03% by mass or less of the heat-cured product of the phenyl-modified organopolysiloxane prepolymer composition.

(5) In the phenyl-modified organopolysiloxane prepolymer composition according to any one of (1) to (4) above according to the present invention, the compounding ratio of the main agent (C) and the curing agent (F) is the mass ratio. It is preferable that (C): (F) = 98: 2 to 75:25.

(6) In the phenyl-modified organopolysiloxane prepolymer composition according to any one of (1) to (5) above according to the present invention, the number of polydimethylsiloxanes (PDMS-1) having silanol groups at both ends. A polydimethylsiloxane having an average molecular weight (Mn) of 18,000 to 60,000, a molecular weight distribution index (Mw / Mn; Mw is a weight average molecular weight) of 1.3 or less, and trialkoxysilyl groups at both ends. It is preferable that the number average molecular weight (Mn) of PDMS-2) is 2,500 to 30,000 and the molecular weight distribution index (Mw / Mn; Mw is a weight average molecular weight) is 1.3 or less.

(7) In the phenyl-modified organopolysiloxane prepolymer composition according to any one of (1) to (6) above according to the present invention, the phenyl-modified hybrid prepolymer (A) has silanol groups at both ends. It is produced by subjecting 1 mol of polydimethylsiloxane (PDMS-1) to a condensation reaction at a molar ratio of at least one of phenyltrialkoxysilane and its hydrolyzate of 0.5 to 5 mol, and is a phenyl-modified hybrid. Of the phenyltrialkoxysilane and its hydrolyzate, the prepolymer (B) has at least 1 mol of one of the polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and its hydrolyzate. It is preferably produced by hydrolyzing and condensing at least one of 0.5 to 3 mol of the above, diphenyldialkoxysilane and at least one of its hydrolysates at a molar ratio of 0.5 to 3 mol. ..

(8) The phenyl-modified organopolysiloxane prepolymer composition according to any one of (1) to (7) above according to the present invention preferably further contains a ceramic filler.

(9) The phenyl-modified organopolysiloxane polymer according to the present invention is obtained by mixing a heat-cured product of any one of the above (1) to (8) phenyl-modified organopolysiloxane prepolymer composition in an atmosphere of 200 ° C. at 500 ° C. The mass loss rate after storage for hours is 5% or less.

(10) The kit for a phenyl-modified organopolysiloxane prepolymer composition according to the present invention comprises a main agent (C) containing phenyl-modified hybrid prepolymers (A) and (B), a linear polysiloxane (D), and a linear polysiloxane (D). It includes a curing agent (F) containing (E).

The phenyl-modified hybrid prepolymer (A) is produced by subjecting polydimethylsiloxane (PDMS-1) having a silanol group at both ends to a condensation reaction with at least one of phenyltrialkoxysilane and its hydrolyzate. Phenyl-modified hybrid prepolymer.

The phenyl-modified hybrid prepolymer (B) is composed of at least one of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and its hydrolyzate, and phenyltrialkoxysilane and its hydrolyzate. It is a phenyl-modified hybrid prepolymer produced by hydrolyzing and condensing at least one of them with at least one of diphenyldialkoxysilane and its hydrolyzate.

The linear polysiloxane (D) is a linear polysiloxane having a triethoxysilyl group at both ends.

The linear polysiloxane (E) is a linear polysiloxane having a trimethoxysilyl group at both ends.

(11) In the kit of the above (10) according to the present invention, the number average molecular weight (Mn) of the linear polysiloxane (D) is 2,500 to 25,000, and the linear polysiloxane (E). ), The number average molecular weight (Mn) is preferably 2,500 to 25,000.

(12) In the kit of the above (10) or (11) according to the present invention, the compounding ratio of the linear polysiloxane (D) and the linear polysiloxane (E) is (D) / by mass ratio. (E) = 0.1 to 6 is preferable.

(13) In any one of the above kits (10) to (12) according to the present invention, the curing agent (F) contains an organic tin compound, and the content of the organic tin compound is cured with the main agent (C). It is preferably 0.03% by mass or less of the heat-cured product of the phenyl-modified organopolysiloxane prepolymer composition obtained by mixing with the agent (F).

(14) In any one of the above kits (10) to (13) according to the present invention, the compounding ratio of the main agent (C) and the curing agent (F) is the mass ratio of (C) :( F). = 98: 2 to 75:25 is preferable.

(15) In any one of the above kits (10) to (14) according to the present invention, the number average molecular weight (Mn) of polydimethylsiloxane (PDMS-1) having a silanol group at both ends is 18, It is 000 to 60,000 and has a molecular weight distribution index (Mw / Mn; Mw is a weight average molecular weight) of 1.3 or less.
Polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends has a number average molecular weight (Mn) of 2,500 to 30,000 and a molecular weight distribution index (Mw / Mn; Mw is a weight average molecular weight) of 1. It is preferably 0.3 or less.

(16) In any one of the above kits (10) to (15) according to the present invention, the phenyl-modified hybrid prepolymer (A) is a polydimethylsiloxane (PDMS-1) having a silanol group at both ends. It was produced by subjecting 1 mol to a condensation reaction at least one of phenyltrialkoxysilane and its hydrolyzate at a molar ratio of 0.5 to 5 mol, and both phenyl-modified hybrid prepolymers (B) were used. At least 1 mol of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at the end and its hydrolyzate, whereas at least 1 mol of phenyltrialkoxysilane and its hydrolyzate 0.5 to It is preferably produced by hydrolyzing and condensing at least one of 3 mol, diphenyldialkoxysilane and its hydrolyzate at a molar ratio of 0.5 to 3 mol.

(17) It is preferable that the kit according to any one of (10) to (16) according to the present invention further contains a ceramic filler.

Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise specified, "parts" and "%" in the examples are based on mass (parts by mass,% by mass). Further, the present invention is not limited to these examples.

[Example: Synthesis of condensed hybrid prepolymer]
Synthesis Example 1: [Preparation of phenyl-modified hybrid prepolymer (Liquid A)]
The reaction vessel equipped with the stirrer, thermometer and dropping line was fully filled with nitrogen gas. At this time, as the nitrogen gas, a nitrogen gas produced by a nitrogen gas production apparatus (UNX-200 manufactured by Japan Unix Co., Ltd.) was used.

As a polydimethylsiloxane (PDMS-1) having a silanol group at both ends, FM9927 manufactured by JNC (number average molecular weight (Mn) = 32,000, molecular weight distribution index (Mw / Mn) = 1.09) 226.2 g, Phenyltriethoxysilane (Ph-1; manufactured by Tokyo Kasei Kogyo Co., Ltd., molecular weight = 240.37) 3.4 g and Matsumoto Fine Chemicals Co., Ltd. tetra (2-ethylhexyl) titanate (organic TA-30; molecular weight = 564.75) 0 .40 g of each was weighed, placed in the above reaction vessel in the order described above, and stirred at a liquid temperature of 80 ° C. for 3 hours using a propeller stirrer to obtain a phenyl-modified hybrid prepolymer (solution A). During the above reaction, nitrogen gas continued to flow.

The molar ratio of PDMS-1 (FM9927) to Ph-1 (phenyltriethoxysilane) is PDMS-1: Ph-1 = 1: 2, and the molar ratio of PDMS-1 to Organtics TA-30 is PDMS-1. : TA-30 = 1: 0.1.

Synthesis Example 2: [Preparation of phenyl-modified hybrid prepolymer (solution B)]
A phenyl-modified hybrid prepolymer (B-1 solution) was prepared in the same manner as in Synthesis Example 1. The raw materials used are as follows.

As a polydimethylsiloxane (PDMS-2) having a triethoxysilyl group at both ends, FM8826 manufactured by JNC (number average molecular weight (Mn) = 20,000, molecular weight distribution index (Mw / Mn) = 1.06) 495. 8 g, diphenyldimethoxysilane (Ph-2; KBM-202SS manufactured by Shinetsu Chemical Industry Co., Ltd., molecular weight = 244.36) 6.1 g, 35 g of water diluted 20-fold with ethanol, phenyltriethoxysilane (Ph-1; Tokyo Kasei) Weighing 11.9 g of Kogyo Co., Ltd., molecular weight = 240.37) and 1.4 g of Tetra (2-ethylhexyl) titanate (Olgatics TA-30; molecular weight = 564.75) manufactured by Matsumoto Fine Chemical Co., Ltd., respectively, in the order described above. The mixture was placed in a reaction vessel and stirred at a liquid temperature of 80 ° C. for 10 hours using a propeller stirrer to obtain a phenyl-modified hybrid prepolymer (solution B). During the above reaction, nitrogen gas continued to flow.

The molar ratio of PDMS-2 (FM8826) to Ph-1 (phenyltriethoxysilane) was PDMS-2: Ph-1 = 1: 2, and the molar ratios of PDMS-2 (FM8826) and Ph-2 (diphenyldimethoxysilane). The ratio is 1: 1 and the molar ratio of PDMS-2 (FM8826) to Organix TA-30 is PDMS-2: TA-30 = 1: 0.1.

Synthesis Example 3: [Phenyl-modified hybrid prepolymer: Preparation of main agent (solution C)]
Put the liquid A prepared in the above synthesis example 1 and the liquid B prepared in the synthesis example 2 into a container at a mass ratio of 7: 3 (solution A: liquid B), and use a sinky rotation / revolution mixer ARE310 at 2000 rpm. Stirring was performed for 120 seconds at 2200 rpm for defoaming for 40 seconds to obtain a phenyl-modified hybrid prepolymer mixed solution (solution C).

Synthesis Example 4: [Preparation of trialkoxysilyl group-terminated polydimethylsiloxane (PDMS) mixed solution (F'solution)]
The reaction vessel equipped with the stirrer and the dropping line was sufficiently filled with nitrogen gas. At this time, as the nitrogen gas, a nitrogen gas produced by a nitrogen gas production apparatus (UNX-200 manufactured by Japan Unix Co., Ltd.) was used.

As a polydimethylsiloxane (PDMS-D) having a triethoxysilyl group at both ends, FM8826 manufactured by JNC (number average molecular weight (Mn) = 20,000, molecular weight distribution index (Mw / Mn = 1.06), both ends As polydimethylsiloxane (PDMS-E) having a trimethoxysilyl group, XP1421 (number average molecular weight (Mn) = 20,000, molecular weight distribution index (Mw / Mn = 1.06)) manufactured by JNC is shown in Table 1. Weighed to a total of 77.8 g at each of the indicated compounding ratios and placed in the above reaction vessel. 22.2 g of n-heptane (manufactured by Daishin Kagaku) was added thereto and mixed under a nitrogen atmosphere to obtain an F'solution. ..

Synthesis Example 5: [Preparation of metal compound-containing curing agent (F "liquid)]
Tokyo Chemical Industry's dibutyltin dilaurate 6.02 g and n-heptane (manufactured by Daishin Chemical Industry) 93.98 g, or Tokyo Chemical Industry's dibutyltin dilaurate 3.01 g and n-heptane (manufactured by Daishin Chemical Industry) 96.99 g. It was placed in the above reaction vessel and mixed under a nitrogen atmosphere to prepare a metal compound-containing curing agent F "solution.

Synthesis Example 6: [Preparation of curing agent (F liquid)]
The mass of 9: 1 (F'liquid: F'liquid) in the glove box filled with nitrogen and continuously supplied with the F'liquid prepared in the above synthesis example 4 and the F'liquid prepared in the synthesis example 5. The stirrer was stirred at room temperature for 30 minutes in the reaction vessel filled with nitrogen and placed in a reaction vessel in a ratio to prepare various curing agents (Liquid F) shown in Table 1.

(Method for producing cured product (H-1 to H-6) of Examples 1 to 6 phenyl-modified organopolysiloxane polymer)
In a container, 97 g of the phenyl-modified hybrid prepolymer mixture (solution C) prepared in Synthesis Example 3 and 3 g of the curing agent (solution F) prepared in Synthesis Example 6 with each formulation shown in Table 1 were placed and manufactured by Shinky. Stirring with a rotation / revolution mixer ARE310 at 2000 rpm for 30 seconds and defoaming at 2200 rpm for 20 seconds, and mixing a curing agent (F solution) containing a trialkoxysilyl group-terminated polydimethylsiloxane (PDMS) -based curing promoting compound. A phenyl-modified organopolysiloxane prepolymer (composition) was obtained.

10 g of this prepolymer composition was filled in an aluminum cup having a cup bottom of φ45 mm, a cup top surface of φ51 mm and a depth of 12 mm, and heat-cured at 80 ° C. for 30 minutes and then at 150 ° C. for 3 hours to obtain phenyl-modified organopoly. A cured siloxane polymer (H-1 to H-6) was obtained.

(Comparative Example 1)
Only the phenyl-modified hybrid prepolymer mixed solution (solution C) prepared in Synthesis Example 3 was placed in the above aluminum cup and heat-cured at 80 ° C. for 30 minutes, then at 150 ° C. for 3 hours, and further at 180 ° C. for 2 hours. A phenyl-modified organopolysiloxane polymer hybrid cured product (h-1) was obtained. It was confirmed after heat treatment at 150 ° C. for 3 hours, but it was not cured.

(Evaluation results of Example 3 and Comparative Example 1)
Comparing the results of the cured product H-3 obtained in Example 3 in which PDMS-D / PDMS-E is 1 and the cured product h-1 obtained in Comparative Example 1 using no curing agent (F liquid). do. Table 2 summarizes the results of comparison of curability, appearance (color), hardness, mechanical properties, and rate of decrease in heat-resistant mass at 200 ° C.

When the curing agent (F) containing a trialkoxysilyl group-terminated polydimethylsiloxane (PDMS) -based curing accelerating compound is used in the composition of the present invention, it does not require a 180 ° C. curing step as compared with the case where it is not used. It can be seen that it can be cured without significantly deteriorating its characteristics. The evaluation methods are summarized below.

[Evaluation of hardness]
[Preparation of sample]
Samples of Examples and Comparative Examples were taken in a PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin) chalet with an inner diameter of 50 mm and a height of 12 mm, and the cured product prepared under the respective cured conditions was subjected to JIS K 6253. Similarly, the hardness of each sample was measured using a type E durometer for soft rubber (low hardness). Those cured at 150 ° C. were evaluated using a cured product obtained by heat treatment at 150 ° C., and those not cured at 150 ° C. were evaluated using a cured product obtained by heat treatment at 180 ° C. for 2 hours. The same applies to the following evaluation samples.

[Evaluation of tensile test]
[Preparation of sample]
A 1 mm thick cured product cured with a PFA petri dish with an inner diameter of 50 mm and a height of 12 mm is cut out with a punching blade of a No. 7 dumbbell in accordance with JIS K6251, and a tensile tester (Shimadzu) in accordance with JIS K6251. The elastic modulus and elongation were evaluated by an autograph manufactured by N = 3).

[Evaluation of heat resistant hardness change rate and heat resistant mass reduction rate]
[Preparation of sample]
The cured product of the aluminum cup was placed in an initial and blower constant temperature machine at 200 ° C., and the hardness and weight after 5 hours were measured, and the rate of change from the initial state was calculated. Moreover, the evaluation after the lapse of 500 hours was also performed in the same manner.

[Inclination experiment]
For the evaluation of the cured state, 10 g of the sample (prepolymer) of the example and the comparative example was filled in an aluminum cup having a bottom inner diameter of 45 mm, an upper inner diameter of 51 mm, and a height of 12 mm, and heat-treated. The sample was placed on a table set at ° and allowed to stand for 30 minutes, and changes in each sample were observed. "○" indicates that the sample surface is the same as when placed on a horizontal surface, "△" indicates that the surface is inclined due to the inclination, but does not overflow from the aluminum cup, and overflows from the aluminum cup onto the inclined table. The ones with "x" and the heat treatment at 150 ° C. for up to 2 hours gave good results in the tilting experiment, and the ones that had not been cured at 180 ° C. were marked with "-".

[Flexibility evaluation]
Fill 5 g of each sample in a PFA petri dish with an inner diameter of 50 mm and a height of 12 mm, fold the cured product prepared under each cured condition in half, and place a steel W clip (width 19 mm-height) 5 mm from the ridge. It was sandwiched between 10 mm) and the state of cracking was confirmed. Those that were sandwiched between W clips and did not crack were evaluated as "○", those that cracked but did not crack were evaluated as "Δ", and those that cracked were evaluated as "×".

(Method for producing Comparative Examples 2 to 8)
Synthesis Example 7: [Preparation method of curing agent component (f'liquid)]
As polydimethylsiloxane (PDMS-1') having silanol groups at both ends, FM9926 manufactured by JNC (number average molecular weight (Mn) = 23,000, molecular weight distribution index (Mw / Mn = 1.10), at both ends As a polydimethylsiloxane (PDMS-D) having a triethoxysilyl group, FM8826 manufactured by JNC (number average molecular weight (Mn) = 20,000, molecular weight distribution index (Mw / Mn = 1.06), trimethoxy at both ends. As the polydimethylsiloxane (PDMS-E) having a silyl group, XP1421 manufactured by JNC (number average molecular weight (Mn) = 20000, molecular weight distribution index (Mw / Mn = 1.06)) is shown in Table 3 for each compounding ratio. Weighed in the same manner as in Synthesis Example 4 to obtain an f'solution.

Synthesis Example 8: [Preparation method of curing agent (f liquid)]
The mass ratio of the f'liquid prepared in Synthesis Example 7 and the F'liquid prepared in Synthesis Example 5 is 9: 1 (f'liquid: F'liquid) in a glove box filled with nitrogen and continuously supplied. The stirrer was stirred at room temperature for 30 minutes in the reaction vessel filled with nitrogen and placed in a reaction vessel in a ratio to prepare each curing agent (liquid f) shown in Table 3.

Synthesis Example 9: [Method for preparing curing agent (f "liquid) of Comparative Examples 7 and 8]
Only the curing agent (f "liquid) shown in Table 3 was used. The preparation method was the same as above. In a glove box filled with nitrogen gas, stirrer stirring was performed in a nitrogen-filled container at room temperature for 30 minutes, and each curing was performed. An agent (f "liquid) was prepared.

(Method for Producing Comparative Examples 2 to 8 Phenyl-modified Organopolysiloxane Polymer Cured Products (h-2 to h-8))
In a container, 97 g of the phenyl-modified hybrid prepolymer mixture (solution C) prepared in Synthesis Example 3 and 3 g of the curing agent (solution f, liquid) prepared in Synthesis Examples 8 and 9 with the formulations shown in Table 3 Was stirred with a Shinky rotation / revolution mixer ARE310 at 2000 rpm for 30 seconds and defoamed at 2200 rpm for 20 seconds to obtain a phenyl-modified organopolysiloxane prepolymer (composition).

This prepolymer composition was heat-cured in the same manner as in Examples 1 to 6 or Comparative Example 1 to obtain a phenyl-modified organopolysiloxane polymer cured product (h-2 to h-8), and the cured state and flexibility were evaluated. Was done.

The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 8 are summarized in Tables 4 to 6.

In Examples 1 to 6, the primary curing (disappearance of fluidity) was completed by heat treatment at 150 ° C. for 1 hour. Further, in Examples 1 to 6, the mass reduction rate after storage at 200 ° C. for 500 hours was 5% or less. On the other hand, in Comparative Examples 1 to 8 in which both or one of the polydimethylsiloxane having a triethoxysilyl group at both ends and the polydimethylsiloxane having a trimethoxysilyl group at both ends is not contained in the curing agent (f), the temperature is 150 ° C. The fluidity did not disappear or the curing was insufficient after 1 hour of heat treatment. The mass reduction rate after storage at 200 ° C. for 500 hours exceeded 5% except for Comparative Example 1. In Comparative Example 7 in which only APTES was used as the curing agent, the color was yellow after the heat treatment, resulting in a poor appearance. Further, in Comparative Example 8 in which only dibutyl tin dilaurate was used as the curing agent, a homogeneous cured product could not be obtained due to expansion caused by the heat treatment. In Comparative Example 1 in which no curing agent was used, the mass reduction rate after storage at 200 ° C. for 500 hours was 5% or less, but a heat treatment temperature of 180 ° C. was required.

Examples 7 to 13, Comparative Example 1
Next, the optimization of the composition of the curing agent (F) was examined.
Synthesis Example 10: [Preparation of phenyl-modified organopolysiloxane prepolymer composition (solution C)]
The curing agent (F solution) prepared in Synthesis Example 6 was placed in a container together with the phenyl-modified hybrid prepolymer mixture solution (C solution) prepared in Synthesis Example 3 at the ratio shown in Table 7, and placed in a Shinky rotation / revolution mixer ARE310. The mixture was stirred at 2000 rpm for 30 seconds and defoamed at 2200 rpm for 20 seconds to obtain a phenyl-modified organopolysiloxane prepolymer (composition). The composition of the curing agent (F) was that of Example 3 in Table 1.

Method for producing phenyl-modified organopolysiloxane polymer cured product (H-7 to 13 and h-1) in which the amount of the curing agent (F liquid) added is changed]
The phenyl-modified organopolysiloxane prepolymer composition having the compositions of Examples 7 to 13 and Comparative Example 1 in Table 7 obtained in Synthesis Example 10 was heat-cured in the same manner as in Examples 1 to 6, and the phenyl-modified organo A cured polysiloxane polymer (H-7 to 13 and h-1) was obtained. The evaluation results of Examples 7 to 13 are summarized in Tables 8 to 10.

As shown in Tables 8 to 10, the curing agent (F liquid) exhibits a function as a curing agent in an amount of 1% by mass or more, more preferably 2% by mass or more, and cures in a short time. It is desirable that it is 3% by mass or more to complete. Even 30% by mass (Example 13) functions as a curing agent, but the mass reduction rate after storage at 200 ° C. for 500 hours is increased as compared with those of 3 to 20% by mass (Examples 9 to 12). , The flexibility is reduced. The upper limit of the curing agent is preferably 25% by mass or less, more preferably 20% by mass or less, in consideration of the flexibility and strength of the target sheet, heat resistance stability (mass reduction rate), and the like.

[Preparation of heat dissipation sheet using phenyl-modified hybrid prepolymer mixed solution (C solution)]
(Example 14: Method for producing a heat dissipation sheet)
Furukawa Denshi's aluminum nitride (f50) having an average particle size of 61 μm was added to 18 g of the phenyl-modified hybrid prepolymer mixed solution (C solution) prepared in Synthesis Example 3 and 2 g of the curing agent of Example 3 prepared in Synthesis Example 6. 56g, 16g of Furukawa Denshi aluminum nitride (f05) with an average particle size of 4.2μm, and 8g of Denka's boron nitride (SP2) with an average particle size of 5.0μm. After kneading with -2 for 10 minutes, the mixture was kneaded for 10 minutes using a three-ceramic roll mill to obtain a compound.

The recovered compound was sandwiched between polymethylpentene resin films and pressure-molded at a press pressure of 3 kgf / cm ² , and molded into a sheet having a size of about 100 mm × 150 mm and a thickness of 0.5 mm. After heating the molded sheet in a warm air circulation dryer at 120 ° C for 8 hours, the polymethylpentene resin film is peeled off and transferred onto a fluorine sheet, and additional firing is performed at 200 ° C for 2 hours to conduct elastic heat conduction. I got a sheet.

(Comparative Example 9: Method for manufacturing a heat dissipation sheet)
In 20 g of the phenyl-modified hybrid prepolymer mixture prepared in Synthesis Example 3, 56 g of Furukawa Denshi aluminum nitride (f50) having an average particle size of 61 μm and 16 g of Furukawa Denshi aluminum nitride (f05) having an average particle size of 4.2 μm are averaged. Add 8 g of Denka boron nitride (SP2) having a particle size of 5.0 μm, knead it with a Fritche motor grinder P-2 for 10 minutes so that it becomes uniform, and then knead it for 10 minutes using a three-ceramic roll mill to obtain a compound. rice field.

The recovered compound was sandwiched between polymethylpentene resin films and pressure-molded at a press pressure of 3 kgf / cm ² , and molded into a sheet having a size of about 100 mm × 150 mm and a thickness of 0.5 mm. After heating the molded sheet in a warm air circulation dryer at 120 ° C for 36 hours, the polymethylpentene resin film is peeled off and transferred onto a fluorine sheet, and additional heat treatment is performed at 200 ° C for 12 hours to conduct elastic heat conduction. I got a sheet. The heat treatment conditions described in Example 14 were insufficiently cured.

(Comparative Example 10: Method for manufacturing a heat dissipation sheet)
To 18 g of the phenyl-modified hybrid prepolymer mixture prepared in Synthesis Example 3, 2 g of 3-aminopropyltriethoxysilane (KBE-903 manufactured by Shinetsu) was added, and 56 g of aluminum nitride (f50) manufactured by Furukawa Denshi having an average particle size of 61 μm was added. Add 16 g of Furukawa Denshi aluminum nitride (f05) with an average particle size of 4.2 μm and 8 g of Denka boron nitride (SP2) with an average particle size of 5.0 μm, and use a Fritche motor grinder P-2 to make it uniform. After kneading for 10 minutes, the mixture was kneaded for 10 minutes using a three-ceramic roll mill to obtain a compound.

The recovered compound was sandwiched between polymethylpentene resin films and pressed at a press pressure of 3 kgf / cm ² , and molded into a sheet having a size of about 100 mm × 150 mm and a thickness of 0.5 mm. After heating the molded sheet in a warm air circulation dryer at 120 ° C for 8 hours, the polymethylpentene resin film is peeled off and transferred onto a fluorine sheet, and additional heat treatment is performed at 200 ° C for 4 hours to conduct elastic heat conduction. I got a sheet.

The average particle size of each of the above-mentioned ceramic fillers is the cumulative medium diameter measured by dispersing each ceramic filler in an IPA solvent using a laser diffraction / scattering type particle size distribution measuring device Microtrack "MT3300EX" manufactured by Nikkiso Co., Ltd. (50% diameter).

The sheets prepared in Example 14 and Comparative Examples 9 and 10 were stored in a warm air circulation dryer at 200 ° C. FIG. 1 shows the result of the mass reduction rate.

When 3-aminopropyltriethoxysilane was used as a curing (accelerating) agent (Comparative Example 10), the curability was improved, but the heat retention was lacking. It can be seen that the product using the curing agent of the present invention (Example 14) can significantly shorten the curing time and maintain the heat resistance characteristics equivalent to those without the curing agent (Comparative Example 9).

[Change example]
The present invention is not limited to the above examples, and changes, deletions and additions may be made without being contrary to the technical idea of the present invention which can be recognized by those skilled in the art from the scope of claims and the description of the specification. It is possible.

The phenyl-modified organopolysiloxane prepolymer composition obtained by mixing a curing agent containing two kinds of the trialkoxysilyl group-terminated siloxane polymer compound of the present invention is a cured product (sealed) having excellent heat resistance, flexibility, and heat resistance maintaining characteristics. (Body, sheet, etc.), especially for the production of encapsulants for SiC, GaN semiconductor power modules and other heat-generating element members, adhesives, heat conductive sheets that are filler composites, insulating sheets, etc. Since it is useful, it has industrial potential.

Claims (15)

At least, the main agent (C) containing the phenyl-modified hybrid prepolymers (A) and (B), and
It is made by mixing with a curing agent (F) containing linear polysiloxane (D) and (E) .
A phenyl-modified organopolysiloxane prepolymer in which the compounding ratio of the linear polysiloxane (D) and the linear polysiloxane (E) is (D) / (E) = 0.1 to 6 in terms of mass ratio. Composition.
(A) A phenyl-modified hybrid prepolymer produced by a condensation reaction of polydimethylsiloxane (PDMS-1) having a silanol group at both ends and at least one of phenyltrialkoxysilane and its hydrolyzate.
(B) At least one of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and its hydrolyzate, and at least one of phenyltrialkoxysilane and its hydrolyzate. A phenyl-modified hybrid prepolymer produced by hydrolyzing and condensing with at least one of diphenyldialkoxysilane and its hydrolyzate.
(D) A linear polysiloxane having a triethoxysilyl group at both ends.
(E) A linear polysiloxane having a trimethoxysilyl group at both ends. The linear polysiloxane (D) has a number average molecular weight (Mn) of 2,500 to 25,000.
The phenyl-modified organopolysiloxane prepolymer composition according to claim 1, wherein the linear polysiloxane (E) has a number average molecular weight (Mn) of 2,500 to 25,000. Claim 1 or claim , wherein the curing agent (F) contains an organic tin compound, and the content of the organic tin compound is 0.03% by mass or less of a heat-cured product of the phenyl-modified organopolysiloxane prepolymer composition. Item 2. The phenyl-modified organopolysiloxane prepolymer composition according to Item 2. Any one of claims 1 to 3 , wherein the compounding ratio of the main agent (C) and the curing agent (F) is (C) :( F) = 98: 2 to 75:25 in terms of mass ratio. The phenyl-modified organopolysiloxane prepolymer composition according to the section. The number average molecular weight (Mn) of polydimethylsiloxane (PDMS-1) having a silanol group at both ends is 18,000 to 60,000, and the molecular weight distribution index (Mw / Mn; Mw is a weight average molecular weight) is 1. 3 or less,
The number average molecular weight (Mn) of the polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends is 2,500 to 30,000, and the molecular weight distribution index (Mw / Mn; Mw is the weight average molecular weight). The phenyl-modified organopolysiloxane prepolymer composition according to any one of claims 1 to 4 , which is 1.3 or less. The phenyl-modified hybrid prepolymer (A) has at least one of phenyltrialkoxysilane and its hydrolyzate 0.5 to 1 mol with respect to 1 mol of polydimethylsiloxane (PDMS-1) having a silanol group at both ends. It was produced by subjecting it to a condensation reaction at a molar ratio of 5 mol.
The phenyl-modified hybrid prepolymer (B) has the phenyltrialkoxysilane and 1 mol of at least one of the polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and a hydrolyzate thereof. Produced by hydrolysis / condensation reaction at least 1 type 0.5 to 3 mol of the hydrolyzate and at least 1 type 0.5 to 3 mol of the diphenyldialkoxysilane and its hydrolyzate. The phenyl-modified organopolysiloxane prepolymer composition according to any one of claims 1 to 5 . The phenyl-modified organopolysiloxane prepolymer composition according to any one of claims 1 to 6 , further comprising a ceramic filler. When the heat-cured product of the phenyl-modified organopolysiloxane prepolymer composition according to any one of claims 1 to 7 is stored in an atmosphere of 200 ° C. for 500 hours, the mass loss rate is 5% or less. There is a phenyl-modified organopolysiloxane polymer. The main agent (C) containing the phenyl-modified hybrid prepolymers (A) and (B), and
A curing agent (F) containing a linear polysiloxane (D) and (E) is provided.
A phenyl-modified organopolysiloxane prepolymer in which the compounding ratio of the linear polysiloxane (D) and the linear polysiloxane (E) is (D) / (E) = 0.1 to 6 in terms of mass ratio. Composition kit.
(A) A phenyl-modified hybrid prepolymer produced by a condensation reaction of polydimethylsiloxane (PDMS-1) having a silanol group at both ends and at least one of phenyltrialkoxysilane and its hydrolyzate.
(B) At least one of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and its hydrolyzate, and at least one of phenyltrialkoxysilane and its hydrolyzate. A phenyl-modified hybrid prepolymer produced by hydrolyzing and condensing with at least one of diphenyldialkoxysilane and its hydrolyzate.
(D) A linear polysiloxane having a triethoxysilyl group at both ends.
(E) A linear polysiloxane having a trimethoxysilyl group at both ends. The linear polysiloxane (D) has a number average molecular weight (Mn) of 2,500 to 25,000.
The kit according to claim 9 , wherein the linear polysiloxane (E) has a number average molecular weight (Mn) of 2,500 to 25,000. The curing agent (F) contains an organic tin compound, and the content of the organic tin compound is a phenyl-modified organopolysiloxane prepolymer composition obtained by mixing the main agent (C) and the curing agent (F). The kit according to claim 9 or 10 , which is 0.03% by mass or less of the heat-cured product. Any one of claims 9 to 11 , wherein the compounding ratio of the main agent (C) and the curing agent (F) is (C) :( F) = 98: 2 to 75:25 in terms of mass ratio. The kit described in the section. The number average molecular weight (Mn) of polydimethylsiloxane (PDMS-1) having a silanol group at both ends is 18,000 to 60,000, and the molecular weight distribution index (Mw / Mn; Mw is a weight average molecular weight) is 1. 3 or less,
The number average molecular weight (Mn) of polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends is 2,500 to 30,000, and the molecular weight distribution index (Mw / Mn; Mw is the weight average molecular weight). The kit according to any one of claims 9 to 12 , which is 1.3 or less. The phenyl-modified hybrid prepolymer (A) has at least one of phenyltrialkoxysilane and its hydrolyzate 0.5 to 1 mol with respect to 1 mol of polydimethylsiloxane (PDMS-1) having a silanol group at both ends. It was produced by subjecting it to a condensation reaction at a molar ratio of 5 mol.
The phenyl-modified hybrid prepolymer (B) has the phenyltrialkoxysilane and 1 mol of at least one of the polydimethylsiloxane (PDMS-2) having a trialkoxysilyl group at both ends and a hydrolyzate thereof. Produced by hydrolysis / condensation reaction at least 1 type 0.5 to 3 mol of the hydrolyzate and at least 1 type 0.5 to 3 mol of the diphenyldialkoxysilane and its hydrolyzate. The kit according to any one of claims 9 to 13 , which is the same as that of the above-mentioned kit. The kit according to any one of claims 9 to 14 , further comprising a ceramic filler.

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