US4292224A — Highly filled thermally conductive elastomers II

Claim 1

Independent Claim 207 words

A dispensable precursor composition for highly filled, thermally conductive elastomers which composition consists essentially of I. 100 parts by weight of an olefinically unsaturated polysiloxane having the formula: ##STR8## wherein at least most of the Ra's and Rb's are selected from (A) saturated hydrocarbyl or hydrocarbyloxy groups having a total of 1 to about 10 carbon atoms that are alkyl or aryl or alkyl and aryl and (B) allyl or vinyl groups, but wherein up to about 25% of the Rb's may be ##STR9## wherein at least most of the Rc's and Rd's are selected from (A) and (B) above but up to about 10% of the Rd's may contain additional siloxane units with substituents selected from (A) and (B) or still additional siloxane units; and still further wherein (1) the average number of siloxane units per polymer molecule is between 100 and 300 and (2) there is an average of above about 1.5 but lower than 6 crosslinking sites selected from the vinyl, allyl or vinyl and allyl groups per polymer molecule; II. about 35-550 parts by weight of finely divided particulate comprising: (A) silica particulate at a weight ratio to the polysiloxane of I. of between about 1:4 to 3:1 wherein the silica particulate comprises:

Claim 2

Dependent Claim 207 words

A dispensable precursor composition for highly filled, thermally conductive elastomers which composition consists essentially of I. 100 parts by weight of an olefinically unsaturated polysiloxane having the formula: ##STR8## wherein at least most of the Ra's and Rb's are selected from (A) saturated hydrocarbyl or hydrocarbyloxy groups having a total of 1 to about 10 carbon atoms that are alkyl or aryl or alkyl and aryl and (B) allyl or vinyl groups, but wherein up to about 25% of the Rb's may be ##STR9## wherein at least most of the Rc's and Rd's are selected from (A) and (B) above but up to about 10% of the Rd's may contain additional siloxane units with substituents selected from (A) and (B) or still additional siloxane units; and still further wherein (1) the average number of siloxane units per polymer molecule is between 100 and 300 and (2) there is an average of above about 1.5 but lower than 6 crosslinking sites selected from the vinyl, allyl or vinyl and allyl groups per polymer molecule; II. about 35-550 parts by weight of finely divided particulate comprising: (A) silica particulate at a weight ratio to the polysiloxane of I. of between about 1:4 to 3:1 wherein the silica particulate comprises:

Claim 3

Dependent Claim 139 words

ground silica having an average particle diameter between about 0.1 and 15 microns; and 2. fumed silica having an average particle diameter between about 0.005 and 0.015 microns; (B) thermally conductive carbon powder at a weight ratio to the polysiloxane of I. of between about 1:10 to 2.5:1; III. a viscosity modifier comprising a silicone oil having a viscosity between about 1000-1,000,000 centistokes at 25° C. at a weight ratio to the particulate of II of between about 1:20 to 1:4 oil to particulate; and IV. a silyl hydride functional polysiloxane oligomer containing between about 5-50 siloxane groups that crosslinks with I at a weight ratio with respect to the polysiloxane of I. of between about 1:3 to 1:20, the silyl hydride functional polysiloxane oligomers having an average of up to about 20 silyl hydride groups per polymer chain.

Claim 4

Dependent Claim 139 words

ground silica having an average particle diameter between about 0.1 and 15 microns; and 2. fumed silica having an average particle diameter between about 0.005 and 0.015 microns; (B) thermally conductive carbon powder at a weight ratio to the polysiloxane of I. of between about 1:10 to 2.5:1; III. a viscosity modifier comprising a silicone oil having a viscosity between about 1000-1,000,000 centistokes at 25° C. at a weight ratio to the particulate of II of between about 1:20 to 1:4 oil to particulate; and IV. a silyl hydride functional polysiloxane oligomer containing between about 5-50 siloxane groups that crosslinks with I at a weight ratio with respect to the polysiloxane of I. of between about 1:3 to 1:20, the silyl hydride functional polysiloxane oligomers having an average of up to about 20 silyl hydride groups per polymer chain.

Claim 5

Dependent Claim 17 words

The precursor composition in accordance with claim 1 wherein the crosslinkable polysiloxane is substantially free of branching.

Claim 6

Dependent Claim 15 words

The precursor composition in accordance with claim 1, wherein the viscosity modifier comprises a dialkylpolysiloxane.

Claim 7

Dependent Claim 13 words

The precursor composition in accordance with claim 3 wherein I (B) is vinyl.

Claim 8

Dependent Claim 21 words

The precursor composition in accordance with claims 1 or 2 or 3 or 4 wherein the conductive carbon powder comprises graphite.

Claim 9

Dependent Claim 49 words

The precursor composition in accordance with claim 5, wherein the silicone oil is selected from the group consisting of dimethyl silicone, methyl phenyl silicone, branched methyl phenoxy silicone, branched chlorophenyl silicone, fluorosilicone, nitride silicone, methyl hydrogen and methyl vinyl silicone oils and combinations of two or more of them.

Claim 10

Dependent Claim 50 words

The precursor composition in accordance with claim 5, wherein the silyl hydride functional polysiloxane has the formula: ##STR10## wherein n averages between about 5 and about 14, R o and A o are selected from the group consisting of alkyl or alkoxy groups having 1-3 carbons, phenyl and phenoxy groups.

Claim 11

Dependent Claim 29 words

The precursor composition in accordance with claims 1 or 2 or 3 or 4 wherein the weight ratio of II. A to II. B is greater than about 2:1.

Claim 12

Dependent Claim 16 words

An elastomer made from the precursor composition of claims 1 or 2 or 3 or 4.

Claim 13

Dependent Claim 24 words

An elastomer in accordance with claim 9, wherein the weight ratio of silica to the polysiloxane of I. is between about 0.9:1 to 1:0.9.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-09-28	1985-03-30	1985-09-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-09-28	1989-03-30	1989-09-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-09-28	1993-03-30	1993-09-29	$7700.00	Window Closed / Lapsed

Highly filled thermally conductive elastomers II

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