Patent US4890056A successfully refreshed from Google Patents.
Patent EP0477681A2 successfully refreshed from Google Patents.
EP0477681A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Heat curable silicone rubber compositions
Assignee: General Electric Co
•
Filing: 1991-09-12
•
Granted: —
•
Expires: 2011-09-12
Abstract
Abstract The present invention provides an improved heat curable silicone composition, having increased tear strength, oil resistance, and reduced compression set, comprising (A) a blend containing (1) a vinyl-containing organopolysiloxane or vinyl-containing organopolysiloxane blend having a viscosity of about 5,000 to about 500,000 centipoise at 25 DEG C, and (2) a vinyl-containing organopolysiloxane or vinyl-containing organopolysiloxane blend having a viscosity of about 8,000,000 to about 100,000,000 centipoise at 25 DEG C; (B) an organopolysiloxane resin copolymer; (C) an organic peroxide catalyst; (D) a filler; and (E) an organohydrogenpolysiloxane.
Inventors
- 👤 Edward Matthew Jeram
- 👤 Brian John Ward
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:40
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/04; C08K5/14; C08L; C08L83/00; C08L83/04; C08G; C08G77/00; C08G77/04; C08G77/12; C08G77/20; C08G77/22; C08G77/24; C08G77/42; C08G77/44; C08G77/70
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
337 words
An improved heat curable silicone composition, having increased tear strength and reduced compression set, comprising by weight: (A) 100 parts of a blend comprising by weight: (1) from about 5 to about 50% of a vinyl-containing organopolysiloxane or vinyl-containing organopolysiloxane blend, wherein the vinyl-containing organopolysiloxane or vinyl-containing organopolysiloxane blend has a viscosity of about 5,000 to about 500,000 centipoise at 25°C; and (2) from about 50 to about 95% of a vinyl-containing organopolysiloxane or vinyl-containing organopolysiloxane blend, wherein the vinyl-containing organopolysiloxane or vinyl-containing organopolysiloxane blend has a viscosity of about 8,000,000 to about 100,000,000 centipoise at 25°C; (B) from about 1 to about 30 parts based on component (A) of an organopolysiloxane resin copolymer comprising (1) R₃SiO 1/2 units and SiO₂ units where R is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation with a ratio of R₃SiO 1/2 units to SiO₂ units ranging from about 0.5:1 to about 1.5:1, wherein the copolymer contains from about 0.5 to 10 weight percent vinyl groups; or (2) R₃SiO 1/2 units, SiO₂ units, and R₂SiO 2/2 units, where R is as defined above, where the ratio of R₃SiO 1/2 units to SiO₂ units is from about 0.5:1 to about 1.5:1, and the R₂SiO 2/2 units are present in an amount of from about 1 to 70 mole percent based on the total number of moles of siloxy units in the copolymer, and where the resinous copolymer contains from about 0.5 to 10.0 weight percent vinyl groups, or (3) mixtures of the units of (1) and (2); (C) from about 0.1 to about 5.0 parts based on component (A) of an organic peroxide free radical curing catalyst, (D) from about 5.0 to about 200 parts based on component (A) of a filler; and (E) from 0.1 to 10 parts based on component (A), of an organohydrogensiloxane having a hydrogen content ranging from about 0.05 to 2.0 percent by weight and having a viscosity ranging from about 5 to about 500 centipoise at 25°C.
Claim 2
Dependent Claim
21 words
The composition of claim 1 wherein component (A)(1) has a viscosity of from about 40,000 to about 500,000 centipoise at 25°C.
Claim 3
Dependent Claim
21 words
The composition of claim 2 wherein component (A)(1) has a viscosity of from about 60,000 to about 150,000 centipoise at 25°C.
Claim 4
Dependent Claim
106 words
The composition of claim 1 wherein component (A)(1) has the formula: wherein Vi is vinyl, R¹ is selected from the class consisting of vinyl, phenyl, alkyl radicals of 1 to 8 carbon atoms, and fluoroalkyl radicals of 3 to 10 carbon atoms and mixtures thereof, and R² is an alkyl radical of 1 to 8 carbon atoms or a fluoroalkyl radical of 3 to 10 carbon atoms or mixtures thereof, w and z vary such that the viscosity of (A)(1) ranges from about 5,000 to about 500,000 centipoise at 25°C, the vinyl concentration being in the range of from about 0.001 to about 10 weight percent.
Claim 5
Dependent Claim
26 words
The composition of claim 1 wherein component (A)(1) is present in an amount ranging from about 10 to about 40 parts by weight based on (A).
Claim 6
Dependent Claim
26 words
The composition of claim 5 wherein component (A)(1) is present in an amount ranging from about 15 to about 25 parts by weight based on (A).
Claim 7
Dependent Claim
21 words
The composition of claim 1 wherein component (A)(2) has a viscosity of from about 20,000,000 to about 35,000,000 centipoise at 25°C.
Claim 8
Dependent Claim
21 words
The composition of claim 7 wherein component (A)(2) has a viscosity of from about 25,000,000 to about 30,000,000 centipoise at 25°C.
Claim 9
Dependent Claim
72 words
The composition of claim 1 wherein component (A)(2) has the formula : wherein Vi is vinyl, R⁴ is a C₁₋₈ monovalent hydrocarbon radical free of aliphatic unsaturation, R⁵ is a C₁₋₈ monovalent hydrocarbon radical, y and t vary such that the viscosity of component (A)(2) ranges from about 8,000,000 to about 100,000,000 centipoise at 25°C and having a vinyl concentration in the range of from about 0.001 to about 0.1 weight percent.
Claim 10
Dependent Claim
26 words
The composition of claim 1 wherein component (A)(2) is present in an amount ranging from about 55 to about 90 parts by weight based on (A).
Claim 11
Dependent Claim
26 words
The composition of claim 10 wherein component (A)(2) is present in an amount ranging from about 60 to about 80 parts by weight based on (A).
Claim 12
Dependent Claim
26 words
The composition of claim 1 wherein component (B) is present in an amount ranging from about 1.0 to about 20 parts by weight based on (A).
Claim 13
Dependent Claim
26 words
The composition of claim 12 wherein component (B) is present in an amount ranging from about 2.5 to about 10 parts by weight based on (A).
Claim 14
Dependent Claim
27 words
The composition of claim 1 wherein the peroxide catalyst is a combination of peroxide catalysts comprising a high temperature peroxide catalyst and a low temperature peroxide catalyst.
Claim 15
Dependent Claim
22 words
The composition of claim 14 wherein the high temperature catalyst is 2,5-dimethyl-2,5-di(t-butyl peroxy) hexane and the low temperature catalyst is 1,1-bis(t-butyl peroxy)-3,3,3-trimethylcyclohexane.
Claim 16
Dependent Claim
26 words
The composition of claim 1 wherein the organic peroxide catalyst is selected from the group consisting of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide, 5-butylcumylperoxide; alpha, alpha prime bis(t-butylperoxy)diisopropylbenzene; and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3.
Claim 17
Dependent Claim
12 words
The composition of claim 16 wherein the organic peroxide catalyst is 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane.
Claim 18
Dependent Claim
24 words
A composition according to claim 1 wherein the filler is a reinforcing filler selected from the group consisting of fumed silica and precipitated silica.
Claim 19
Dependent Claim
26 words
The composition of claim 1 wherein the filler is present in an amount ranging from about 10 to about 100 parts by weight based on (A).
Claim 20
Dependent Claim
26 words
The composition of claim 19 wherein the filler is present in an amount ranging from about 30 to about 70 parts by weight based on (A).
Claim 21
Dependent Claim
65 words
The composition of claim 1 wherein the hydride polysiloxane is a linear diorganopolysiloxane polymer having the formula wherein R⁶ is hydrogen or a C₁₋₈ monovalent hydrocarbon radical free of alipahtic unsaturation, p and q vary such that the viscosity of the organohydrogenpolysiloxane varies from 10 to 100 centipoise at 25°C, and the hydrogen content of the polymer varies from 0.05 to 2.0 percent by weight.
Claim 22
Dependent Claim
61 words
The composition according to claim 1 wherein the organohydrogenpolysiloxane is a hydride resin containing monovalent HR 7 2 SiO 1/2 units and tetravalent SiO₂ units wherein R⁷ is a C₁₋₈ monovalent hydrocarbon radical free of aliphatic unsaturation, the R⁷+H to Si ratio varies from 1.0 to 2.7, and the hydride content of the resin varies from 0.05 to 2.0 weight percent.
Claim 23
Dependent Claim
63 words
The composition of claim 1 wherein the hydride-containing polysiloxane is a hydride resin containing HR 7 2 SiO 1/2 units, divalent (R⁷)₂SiO 2/2 units, and SiO₂ units, wherein R⁷ is a C₁₋₈ monovalent hydrocarbon radical free of aliphatic unsaturation, the R⁷+H to Si ratio varies from 1.2 to 2.7, and the hydride content of the resin varies from 0.05 to 2.0 weight percent.
Claim 24
Dependent Claim
26 words
The composition of claim 1 wherein component (E) is present in an amount ranging from about 0.5 to about 8 parts by weight based on (A).
Claim 25
Dependent Claim
26 words
The composition of claim 24 wherein component (E) is present in an amount ranging from about 0.8 to about 5 parts by weight based on (A).
Claim 26
Dependent Claim
26 words
A composition according to claim 1 further comprising by weight (F) from about 0.5 to about 20 parts by weight based on (A) of magnesium oxide.
Claim 27
Dependent Claim
29 words
The composition of claim 26 wherein the magnesium oxide is present in an amount within the range of about 1 to about 10 parts by weight based on (A).
Claim 28
Dependent Claim
40 words
A composition according to claim 1 further comprising by weight (G) from about 0.01 to about 20 parts by weight based on (A) of (G) a cerium compound or from about 0.01 to about 10 parts by weight of tetramethyldivinyldisilazane.
Claim 29
Dependent Claim
12 words
The composition of claim 28 wherein the cerium compound is cerium hydroxide.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.