JP2510577B2 - Curable silicone gel composition - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to polyorganosiloxane compositions that cure to form silicone gels. In particular, this composition has an extremely excellent cold resistance that does not cause crystallization of the gelled product even at low temperatures (-60 ° C), with little inhibition of the curability with respect to the surrounding atmosphere and foreign substances and little change in the penetration of the gel. have. Therefore, the composition of the present invention can be recommended as a material useful for improving the productivity and reliability of electric / electronic parts.

[Technical background of the invention and its problems]

A so-called addition type silicone composition is a so-called addition type silicone composition in which a polyorganosiloxane having a vinyl group and a polyorganosiloxane hydrogensiloxane having a hydrogen atom bonded to a silicon atom are subjected to an addition reaction by a catalytic action of a platinum compound to obtain a cured product. It is already used in a wide range of industrial fields including the electronics industry. Among them, gel compositions whose crosslink density is adjusted to a low level are widely used for potting, coating or encapsulation of delicate electronic parts because of their unique physical properties.

Such silicone gel compositions have long been well known. For example, in U.S. Pat.No. 3,020,260,
(A) The base polymer is composed of RViSiO units, R ₂ SiO units and CH ₃ R ₂ SiO units, and has a viscosity at 25 ° C. of 100 to 10
Polyorganosiloxane having a substantially linear structure of 000 cSt (wherein R in the unit formula is a methyl group and a phenyl group, and Vi represents a vinyl group), (b) a general formula , A liquid polyorganohydrogensiloxane having a viscosity of 10,000 cSt or less at 25 ° C., and (c) an organosiloxane potting compound composed of a platinum catalyst are exemplified.

However, in the composition comprising (a) to (c), (a)
Since the component is a substantially linear polyorganosiloxane, if the phenyl group cannot be used for some of the organic groups due to the importance of electrical characteristics such as arc resistance and the cost of the product, the Cold resistance can be a major problem in potting and encapsulation of electronic components. In such a case, the composition may further include (d) 1 to 7 mol% CH ₃ SiO _1.5 units, (CH ₃ ) ₃ S
iO _0.5 consists essentially of 1 to 8 mol% and other (CH ₃ ) ₂ SiO units of 85 to 95 mol% and has a viscosity at 25 ° C. of 20 to 10,000.
A composition is described in which a branched polymethylsiloxane of cSt is added as a diluent in a proportion of 23% by weight or less based on the total weight of (a) + (b) + (c) + (d). There is.
In this case, although the addition of the component (d) improves the cold resistance, it basically does not have a group that undergoes a crosslinking reaction, so that the surface of the cured product may have oily substance bleeding or gel. There was a defect that the strength of the shaped material became too weak.

In order to improve these drawbacks, JP-A-58-7452 discloses that (e) base polymer contains (CH ₃ ) ₂ SiO units of 80
~ 96.5 mol%, CH ₃ SiO _1.5 unit is 2.0 to 10.0 mol%, (CH
₃ ) ₃ SiO _0.5 unit is 1.25 to 6.0 mol% and (CH ₃ ) ₂ (CH ₂ =
CH) SiO _0.5 unit is a branched vinyl group-containing polymethylsiloxane consisting of 0.25 to 4.0 mol%, (e) having an average of more than 1 silicon-bonded hydrogen atom per molecule, and substantially A curable silokian composition comprising the same polyorganohydrogensiloxane and (g) the same platinum catalyst as the component (c) is described. In this case, since the same branched polyorganosiloxane (e) component (d) as the component (d) is used for the base polymer, the cold resistance is superior to that of the above-mentioned US patent, and a vinyl group is used as a crosslinking reaction group. Since it has, it is improved so that the oily substance does not bleed to the surface of the cured product. However, in order to obtain a soft gel-like material in this curable composition,
It is necessary to strictly determine the ratio of the vinyl group in the component (e) to the silicon-bonded hydrogen atom in the component (e) to control the crosslink density. That is, in order to obtain a soft gel, it is necessary to keep the crosslink density extremely low. Therefore, it becomes difficult to control the crosslinking reaction, for example, the curing does not proceed sufficiently due to the inclusion of trace amounts of impurities that suppress the crosslinking reaction or contact with foreign substances, and often the unreacted silicon bond in the reaction system. Hydrogen atoms and silicon-bonded vinyl groups remain. For this reason, when the obtained soft gel is exposed to high temperatures, the hardness of the gel changes due to heat, and adverse effects such as stress are exerted on fine parts such as high-density electronic parts to improve reliability. As a result, it has been pointed out as a major drawback in the industry.

[Object of the Invention]

The object of the present invention is to eliminate such drawbacks, such as high reliability is obtained when used as a soft insulating protective agent for high-density electrical and electronic parts, excellent in insulation, It is intended to provide a curable silicone gel composition having features such as little change in properties due to heating and excellent cold resistance.

[Structure of the Invention] As a result of intensive studies to achieve such an object, the present inventors have found that H (C
A branched polymethylhydrogensiloxane having H ₃ ) ₂ SiO _0.5 units at its terminals, which is previously prepared from H (CH ₃ ) ₂ SiO _0.5
By using polymethylhydrogensiloxane that has a low unit content and is limited to a narrow range, the vinyl group content of the vinyl group-containing polyorganosiloxane that serves as a cross-linking agent can be easily adjusted without being severely limited. The present invention has been completed by finding that a soft gel can be obtained and that the gel has little change in hardness (penetration) by heating and is excellent in cold resistance.

It was also found that the composition of the present invention does not impair the curability even when contacted with a foreign substance that affects the curability of gel such as solder flux.

That is, the present invention relates to (A) (CH ₃ ) ₂ SiO unit 80 to 97.7 mol%, CH ₃ Si0 _1.2 unit
It basically consists of 2.0 to 10.0 mol% (CH ₃ ) ₃ SiO _0.5 unit 0.2 to 9.0 mol% and H (CH ₃ ) ₂ SiO _0.5 unit 0.1 to 1.0 mol%, and the viscosity at 25 ° C is in the range of 50 to 10,000 cP. (B) a polyorganosiloxane having an average of at least 1.5 alkenyl groups per molecule, the alkenyl groups having an average of 0.2 to about 1 mol / mol of silicon-bonded atoms of the polymethylhydrogensiloxane of component (A). It is selected so as to be 50 moles, and is 0.1 per 100 parts by weight of the component (A).
To 30 parts by weight, and (C) the catalyst for addition reaction, and the total amount of the components (A) and (B), the amount of the catalytic metal element is 0.01 to 50 ppm. Curable silicone gel composition.

The component (A) used in the present invention is a base polymer of a silicone gel composition, has a branched molecular structure so as to obtain excellent cold resistance after curing, and has several molecular chain terminal ends. It is a polyorganohydrogensiloxane selected by arranging highly reactive silicon-bonded hydrogen atoms so as not to be susceptible to vulcanization inhibition by curing speed or contamination of foreign matter during curing or contact with it. That is, this polyorganohydrogensiloxane has a dimethylsiloxane unit [(CH ₃ ) ₂ SiO], a monomethylsiloxane unit (CH ₃ SiO _1.5 ), a trimethylsiloxane unit [(C
H ₃ ) ₃ SiO _0.5 and dimethylhydrogen siloxane unit [(CH ₃ )
₂ HSiO _0.5 ] is a liquid polymer basically composed of.

This polyorganohydrogensiloxane has a dimethylsiloxane unit as a main constituent unit because it needs to be a liquid having an appropriate viscosity. Therefore, this unit can vary from 80 to 97.7 mol% of all siloxane units in the polymer, but preferably in the polymer
Good results are obtained when it accounts for 90 mol% or more. The following monomethylsiloxane units can comprise a range of 2.0 to 10.0 mol% of all siloxane units in the polymer,
More preferably, 3.0 to 8.0 mol% will give good results. This CH ₃ SiO _1.5 unit is a trifunctional structural unit and is used to make the molecular structure of the polyorganosiloxane branched (comb type). The polyorganosiloxane having this branched structure has linear flowability even at -60 ° C, whereas linear polydiorganosiloxane does not flow and crystallizes at around -40 ° C, and has a temperature range of -100 to 100 ° C. Also in the result of measuring the crystallization temperature (Tm) by a differential scanning calorimeter, Tm was not observed.

In addition, the following trimethylsiloxane units, which primarily act as polymer end-terminating groups, are used to stabilize the polyorganosiloxane and control its viscosity. This unit may occupy a range of 0.2 to 9.0 mol% of the siloxane unit. The last dimethylhydrogensiloxane unit, like the trimethylsiloxane unit, not only utilizes the effect of the polymer as a terminal terminating group, but also carries out a platinum-catalyzed crosslinking reaction between an alkenyl group in the silicone gel composition and a silicon-bonded hydrogen atom. Used for.
This unit is in a relatively narrow range of 0.1 to 1.0 mol% of all siloxane units in the polymer, more preferably 0.2 to 0.5 mol%.
It can be included in the range of. What previously set narrow this range, (1) to easily obtain a soft silicone gel, (2) H (CH _{3) 2} silicon-bonded hydrogen atoms of SiO _0.5 units H (CH ₃₎ a SiO units hydrogen Highly reactive with alkenyl groups compared to atoms, because it is effectively used as a cross-linking point,
This is because it is difficult to remain as an unreacted group in the cured silicone gel. However, if it is less than 0.1 mol%, it becomes difficult to form a gel, and if it exceeds 1.0 mol%, the gel becomes too hard, or a special alkenyl group-containing polyorganosiloxane is required to adjust the hardness to a low level. In addition, since it is necessary to strictly control the amount of alkenyl groups, problems such as inhibition of vulcanization occur, which is not preferable.

Such polyorganohydrogensiloxane can be prepared by hydrolyzing dimethyldichlorosilane, methyltrichlorosilane, trimethylchlorosilane and dimethylhydrogenchlorosilane by a known method, and then re-equilibrating it with an acidic catalyst, or dimethylchlorosilane. After obtaining a co-hydrolyzate of methyltrichlorosilane and trimethylchlorosilane, H (CH ₃ ) ₂ SiOSi (CH ₃ ) ₂ H and octamethylcyclotetrasiloxane are added, and an acid catalyst such as sulfuric acid and acid clay is present. Obtained by equilibrating below. Similarly, substituting the respective alkoxysilanes for the above chlorosilanes will also yield polymers suitable for the present invention.

The viscosity of the polyorganohydrogensiloxane used in the present invention at 25 ° C. is selected from the range of 50 to 10,000 cP in view of fluidity and workability during use. If the viscosity is less than 50 cP, sufficient strength cannot be obtained for the silicone gel, and if it exceeds 10,000 cP, workability such as fluidity and defoaming property is deteriorated, which is not preferable.

Thus, a polyorganohydro having a higher reactivity of silicon-bonded hydrogen atoms and a relatively low proportion of such silicon-bonded hydrogen atoms, as compared with conventional silicone gel compositions having a vinyl group as a base polymer. The silicone gel composition of the present invention having a gensiloxane as a base polymer has a curability depending on the amount of alkenyl groups of the following alkenyl group-containing polyorganosiloxane which is the component (B) and the molar ratio thereof to silicon-bonded hydrogen atoms. Not only is it not easily affected, but it also has the advantage that it is less susceptible to vulcanization inhibition even against foreign matter and solder during the manufacture of electronic components.

The component (B) used in the present invention is an alkenyl group-containing polyorganosiloxane, and acts as a cross-linking agent that forms a gel-like substance by addition reaction with the silicon-bonded hydrogen atom of the component (A) in the presence of a catalyst. It is a thing. Therefore, the component (B) needs to contain at least 1.5 alkenyl groups on average in one molecule in order to form crosslinks.

Examples of the alkenyl group include a vinyl group, an allyl group, a cyclopentenyl group, a cyclohexenyl group, a 2- (4-vinylcyclohexyl) ethyl group, a p-vinylphenyl group and the like, but they are easy to synthesize and obtain. Vinyl groups are particularly preferred. In addition, the number of alkenyl groups bonded to silicon is preferably 1 or less to the same silicon atom, and two or more alkenyl groups can be bonded to the same silicon atom. It is not normally used because it is not used effectively, its heat resistance is reduced, and it is difficult to synthesize or obtain it as a raw material. Further, the alkenyl group may be bonded to either the terminal of the molecule, the silicon atom in the middle of the molecule, or both of them.

Examples of the residual organic group bonded to the silicon bond of the component (B) include a methyl group, a phenyl group, and a 3,3,3-trifluoropropyl group, but the compatibility with the component (A) is obtained. It is preferable that all or most of them are methyl groups because they are easily treated. The shape of the molecule of the component (B) may be linear or branched, and its viscosity is not particularly specified, either.
It is desirable to select a polyorganosiloxane having good compatibility with the component (A).

Such component (B) is a chlorosilane such as dimethylvinylchlorosilane, methylvinyldichlorosilane, vinyltrichlorosilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, methylvinylphenylchlorosilane, diphenyldichlorosilane, phenyltrichlorosilane, Using 3,3,3-trifluoropropylmethyldichlorosilane, tetrachlorosilane or corresponding alkoxysilanes,
Similar to the component (A), it can be obtained by a known method such as co-hydrolysis culture, equilibration using an acid or basic polymerization catalyst, or copolymerization using a low molecular weight polyorganosiloxane.

In the case of carrying out the present invention using the alkenyl group-containing polyorganosiloxane obtained in this way, the added weight part is, as a rule, the alkenyl group in the component (B) is a silicon bond in the component (A). An average of 0 per mole of hydrogen atoms.
It should be chosen to be 2-5 moles.

When the amount of the alkenyl group is less than 0.2 mol based on the silicon-bonded hydrogen atoms in the component (A), a satisfactory gel-like product cannot be obtained, and when it exceeds 5 mol, it may be used. However, unreacted alkenyl groups are not preferable because they lower the heat resistance of the gel and cause curing failure.

Next, in the present invention, since the skeleton of the polysiloxane of the component (A) has a branched structure, the cold resistance is improved, and the component (A) needs to be the main component.
Therefore, it is inconvenient to define the addition amount of the component (B) only by the molar ratio of the silicon-bonded alkenyl groups to the silicon-bonded hydrogen atoms in the component (A). Therefore, it is necessary to limit the component (B) of the present invention also by the added weight. That is, in the present invention, the addition amount of the component (B) should be selected from the range of 0.1 to 30 parts by weight with respect to 100 parts by weight of the component (A) while maintaining the above alkenyl group / silicon bonded hydrogen atom ratio. . In this case, the amount of alkenyl groups in the component (B) is preferably 0.15 to 50% with respect to the total amount of organic groups in the polyorganosiloxane of the component (B). The amount of the component (B) added and the amount of the alkenyl group are preferably polyorgano in consideration of maintaining and improving the cold resistance of the gel, crosslinking efficiency, heat resistance and workability such as mixing, defoaming and fluidity. The amount of siloxane added is 0.2 to 20 parts by weight, and the alkenyl group based on the total amount of organic groups is in the range of 0.25 to 25%. More preferably, the addition of 0.5 to 10 parts by weight of polyorganosiloxane gives 1.0 to 1 of the alkenyl groups based on the total amount of organic groups.
It is in the range of 5%. If the addition amount of the component (B) is less than 0.1 part by weight, a polyorganosiloxane containing a large amount of silicon-bonded alkenyl groups must be used, which causes reduction in heat resistance, non-uniformity of mixing and crosslinking, etc. Is not desirable. On the other hand, if the addition amount of the component (B) exceeds 30 parts by weight, the cold resistance of the gel cured product is impaired, which is not preferable.

The component (C) used in the present invention is a catalyst for accelerating the addition reaction between the silicon-bonded hydrogen atom of the component (A) and the alkenyl group of the component (B), which is a known chloroplatinic acid, Reaction products of chloroplatinic acid and alcohol, complexes of platinum and olefins, complexes of platinum and ketones, complexes of platinum and vinyl siloxane, complexes of platinum and triphenylphosphine or triphenylphosphite, etc. Platinum catalysts exemplified, tetrakis (triphenylphosphine) palladium, palladium catalysts exemplified by a mixture of palladium black and triphenylphosphine, or rhodium catalysts such as complexes of rhodium and phosphine compounds can be used. A platinum-based catalyst is particularly preferable because of its catalytic effect and easy handling. The blending amount of component (C) is
The amount of the catalytic metal element is in the range of 0.01 to 50 ppm with respect to the total amount of the components (A) and (B). 0.01ppm
If it is less than 50 ppm, a gel-like product cannot be obtained because the addition reaction does not proceed sufficiently, and if it exceeds 50 ppm, the heat resistance is lowered and the features of the present invention cannot be exhibited.

The composition of the present invention comprises 3-methyl-1-butyn-3-ol, 3.5 in addition to the components (A), (B) and (C) described above.
-Acetin alcohols such as dimethyl-1-hexyn-3-ol, or those alcohols and silanes and / or
Or Si-O-C via oxygen atom with polysiloxane
An addition reaction inhibitor such as an alkynyl group-containing silane and / or polysiloxane which is a type reaction product may be included. By using such a platinum-based catalyst having a low activity near the room temperature or in the presence of such a reaction inhibitor, the components (A) to (C) can be stored in the same container, and when actually used, they are weighed and mixed. It is convenient because it eliminates the need for defoaming. Also,
When the reaction speed and room temperature curing are important, use a highly active platinum-based catalyst and adjust with or without the use of a reaction inhibitor as appropriate to adjust the components (A) and (B) +
The component (C) may be placed in a separate container, and they may be uniformly mixed immediately before use and degassed under reduced pressure before use.

In addition, the composition of the present invention may further contain an inorganic filler, if necessary, to adjust the workability of the composition, the hardness after curing, the mechanical strength, etc. according to the application. Examples of such an inorganic filler include fumed silica, silica airgel, precipitated silica, and silica whose surface is treated with an organic silane and / or siloxane. Furthermore, an organic solvent such as toluene or hexane, a viscosity adjusting or diluting agent such as polydimethylsiloxane, an azo or anthraquinone type organic pigment, an oxide of various metals or a heat resistance improver comprising fatty acid salts of these metals A silane coupling agent as an adhesion improver, a system neutralizing agent, etc. may be used in combination as long as the effects of the present invention are not impaired.

〔The invention's effect〕

The curable silicone gel composition of the present invention having the above-mentioned composition is cured at room temperature or with slight heating to be converted into a soft gel-like material excellent in impact absorption property, constant temperature property and electric insulation property. In addition, the composition of the present invention has a high resistance to vulcanization inhibition by the flux in the soldering process in the production stage of electric / electronic parts, and therefore has an advantage that curing failure is unlikely to occur. There is. Therefore, when the composition of the present invention is applied to electric / electronic parts, it is not necessary to pay attention to the catalyst with the soldering flux in the designing and manufacturing process of parts as compared with the conventional composition, so that the complicated cleaning process so far can be performed. The effect that it can be greatly simplified is obtained. Furthermore, the cured silicone gel has excellent flexibility with almost no change in penetration even at a low temperature of -60 ° C, which makes it suitable for electronic parts, especially hybrid ICs and high-density mounted electronic parts. It has a remarkable effect in achieving reliability and long life.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, Reference Examples and Comparative Examples. In the examples, all parts are parts by weight, Me is a methyl group, and Vi is a vinyl group.

Reference Example 1 0.24 parts of HMe ₂ SiOSiMe ₂ H, 85.46 parts of octamethylcyclotetrasiloxane (Me ₂ SiO) ₄ and 1.0 part of acid clay were placed in a separable flask and kept at 60 ° C. for 4 hours while stirring to allow equilibration reaction. It was Then 60 mol% of Me ₂ SiO, 3
Cohydrolyzate from each chlorosilane having a basic structural composition of 3.3 mol% MeSiO _1.5 and 6.7 mol% Me ₃ SiO _0.5 14.3
Part of the reaction mixture was subjected to equilibration reaction at 80 ° C. for 3 hours, and after cooling, the acidic white clay was filtered off under reduced pressure from the reaction mixture to obtain colorless transparent polyorganohydrogensiloxane of the filtrate at 150 ° C. and 10 mmHg. A low fraction was distilled off under reduced pressure to obtain a base polymer (I). Base polymer (I) is 25 ℃
Had a viscosity of 490 cP, and its hydrogen content was measured to find that it contained 0.27 mol% of HMeSiO _0.5 unit. The remaining units are 93.9 mol% Me ₂ SiO units, MeSi
The O _1.5 unit was 4.86 mol% and the Me ₃ SiO _0.5 unit was 0.98 mol%.

Reference Example 2 HMe ₂ SiOSiMe ₂ H 0.26 parts, Me ₃ SiO (Me ₂ SiO) ₂ SiMe ₃ 1.38
And 98.36 parts of (Me ₂ SiO) ₄ were charged, 1.0 part of acid clay was added as in Reference Example 1, and the equilibration reaction was carried out at 60 ° C. for 8 hours. After filtering off the acid clay, the filtrate was heated at 150 ° C for 1
The low fraction was distilled off under reduced pressure at 0 mmHg. The obtained polymethyl hydrogen siloxane was a colorless and transparent liquid having a substantially linear structure, and had a viscosity at 25 ° C. of 680 cP. This base polymer (II) contains Me ₂ S as each unit amount.
iO unit 99.02 mol%, Me ₃ SiO _0.5 unit 0.72 mol% and HMe ₂
It consisted of _0.5 units of SiO _0.5 0.26 mol%.

Example 1 To 100 parts by weight of the base polymer (I) obtained in Reference Example 1,
Terminated with _0.5 units of Me ₃ SiO as a cross-linking agent, containing 10 mol% of MeViSiO units, the balance consisting of Me ₂ SiO units, 25 ° C
Viscosity of 4,000 cP at polymethylvinylsiloxane
0.02 parts of a solution of chloroplatinic acid in 2-ethylhexanol prepared to contain 4.0 parts and 4.0% by weight of platinum metal (7.6 p of platinum metal based on total polyorganosiloxane).
(amount of pm) was uniformly mixed to obtain a curable silicone gel composition (1). This composition (1) was a colorless and transparent oily substance having a viscosity of 510 cP at 25 ° C. The Vi-Si / H-Si ratio in this composition was 1.454.

Take 30 ml of composition (1) in a 50 ml glass beaker and
It was heat-cured for 1 hour in a hot air dryer at 0 ° C. to obtain a transparent silicone gel. After cooling it, the penetration (5 second value) was measured using a 1/4 scale cone according to ASTM D 1403 in order to measure the hardness of the silicone gel. The result was a penetration of 71 as shown in Table 1. Next, the silicone gel was kept in a low temperature bath at −60 ° C. for 169 hours, and then the penetration was measured immediately after it was taken out. The penetration is shown in Table 1. The hardness of the gel did not change even at -60 ° C.
The gel was returned to room temperature and put in a drier at 200 ° C. for 72 hours for heat resistance test. The results are shown in Table 1. The needle penetration after taking out and cooling was 68, and there was almost no change.

Next, a differential scanning calorimeter (DSC) DuPont 990 (trade name of DuPont) was used to obtain a differential scanning calorimetric curve of the cured silicone gel in the range of -100 to 100 ° C. In the analysis result, as shown in Table 1, no peak indicating the crystallization temperature (Tm) of the gel was observed.

Then, the silicone gel composition (1) was tested for solder flaking resistance. To evaluate the flux resistance, a 2% toluene solution of abietic acid as a rosin, which is the main component of the flux, was added to the composition at 1% by weight and
% And 3% were added and uniformly mixed, and then each sample was heat-cured under the same conditions as described above. The penetration of each of the obtained gels was measured, and the influence thereof was examined. The results, as shown in Table 1, clearly show that the composition is resistant to flux (abietic acid).

Example 2 Me ₂ SiO unit 96.5 mol%, MeSiO _1.5 unit 2.0 mol%, Me ₃
A polymethylhydrogensiloxane having _0.5 units of SiO _0.5 and _0.5 units of HMe ₂ SiO _0.5 and having a viscosity at 25 ° C. of 5,400 cP was obtained in the same manner as in Reference Example 1. Platinum complex obtained by reacting 100 parts of this base polymer (III) with 2.0 parts of polymethylvinylsiloxane used in Example 1 and chlorogoldplatinic acid as a platinum catalyst and divinyltetramethyldisiloxane (0.8 weight of platinum metal) % Included)
As platinum metal for all polyorganosiloxane
A uniform silicone gel composition (2) was obtained by adding 0.064 part, which is the amount of pm. Vi-Si / H-Si in this composition
The ratio was 0.39.

Take 30 ml of composition (2) in a 50 ml glass beaker and
It was heated and cured at 0 ° C. for 30 minutes to obtain a transparent soft silicone gel. The same test as in Example 1 was performed on this cured gel. The results are shown in Table 1.

Comparative Example 1 Linear base polymer (II) 10 obtained in Reference Example 2
Comparative composition 11 was obtained by uniformly mixing 0 part by weight, 2.8 parts of polymethylvinylsiloxane used in Example 1 and 0.08 part of the platinum complex used in Example 2. Vi-Si / H in this composition
The ratio of -Si was 1.06.

The same test as in Example 1 was carried out using Comparative Composition 11, and the results are shown in Table 1. As is clear from Table 1, a Tm peak was observed at -41 ° C in the DSC measurement. Even in the penetration measurement at −60 ° C., it shows that the flexibility is completely lost.

Comparative Example 2 100 parts of polydimethylsiloxane having dimethylvinylsiloxane units at both ends and having a viscosity of 5,000 cp at 25 ° C. as a base polymer, and heptamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane and pentamethylcyclosiloxane as a crosslinking agent. 1.5% of a mixture containing 10 mol%, 85 mol% and 5 mol% of tetrasiloxane, respectively.
Parts and 0.07 part of the platinum complex used in Example 2 were uniformly mixed to obtain Comparative Composition 12. Vi-Si / H in this comparative composition
The -Si ratio was 0.76.

The same test as in Example 1 was carried out using Comparative Composition 12, and the results are shown in Table 1.

Comparative Example 3 Me ₂ SiO unit 94.0 mol%, MeSiO _1.5 mol%, Me ₃ SiO _0.5
Unit 2.5 mol%, Me ₂ ViSiO _0.5 unit 0.5 mol%
100 parts of polymethylvinylsiloxane having a viscosity of 1,500 cP at 5 ° C., 3.9 parts of the crosslinking agent used in Comparative Example 2 and Example 2
0.7 parts of the platinum complex of was uniformly mixed to obtain Comparative Composition 13. The Vi-Si / H-Si ratio of this composition 13 was 0.5.

The same test as in Example 1 was performed on the comparative composition 13, and the results are shown in Table 1. As is clear from Table 1, in Comparative Composition 13, the heat resistance was poor and no good result was observed in the flux resistance.

Example 3 100 parts by weight of the base polymer (III) used in Example 2 was end-terminated with _0.5 unit of Me ₂ ViSiO and 5.
0 mol%, diphenylsiloxane unit 5.0 mol%, the balance
A silicone gel composition (3) was obtained by uniformly mixing 3.0 parts of polymethylvinylphenylsiloxane consisting of Me ₂ SiO units and having a viscosity of 1,000 cP at 25 ° C. and 0.06 part of the platinum complex of Example 2. The Vi-Si / H-Si ratio in this composition was 0.5.

Using the composition (3), heat curing and testing were carried out in the same manner as in Example 1. The results are shown in Table 1.

Claims (7)

(57) [Claims] 1. (A) (CH ₃ ) ₂ SiO units 80 to 97.7 mol%, C
H ₃ Si 0 _1.2 unit 2.0 to 10.0 mol% (CH ₃ ) ₃ SiO _0.5 unit 0.2 to
It is basically composed of 9.0 mol% and H (CH ₃ ) ₂ SiO _0.5 unit of 0.1 to 1.0 mol%, and the viscosity at 25 ° C. is in the range of 50 to 10,000 cP. A polyorganosiloxane having one alkenyl group, the alkenyl group being selected to be 0.2 to 5.0 moles on average per mole of silicon-bonded hydrogen atoms of the polymethylhydrogensiloxane of component (A), and (A ) 0.1 to 30 parts by weight with respect to 100 parts by weight of the component, and 0.01 to 50 ppm as the amount of the catalytic metal element with respect to the total amount of the (C) addition reaction catalyst and the components (A) and (B). A curable silicone gel composition, characterized in that 2. The proportion of H (CH ₃ ) ₂ SiO _0.5 units in the component (A) is 0.2 to 0.5 mol%.
The composition according to the item. 3. The composition according to claim 1, wherein the alkenyl group of the component (B) is a vinyl group. 4. The component (B) is 0.15 to 50% of the total amount of organic groups.
The composition according to any one of claims 1 to 3, which is a polyorganosiloxane containing the above alkenyl group. 5. The component (B) is 0.25 to 25% with respect to the total amount of organic groups.
Which is an alkenyl group-containing polyorganosiloxane, the addition amount of which is 0.2 to 100 parts by weight of the component (A).
The composition according to any one of claims 1 to 4, which is in the range of 20 parts by weight. 6. The component (B) is a polyorganosiloxane containing 1 to 15% of alkenyl groups based on the total amount of organic groups, and the addition amount thereof is 0.5 to 10 per 100 parts by weight of the component (A).
The composition according to any one of claims 1 to 5, which is in the range of parts by weight. 7. The composition according to claim 1, wherein the component (C) is a platinum compound.