Low compression set silicone elastomers
First Claim
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1. A fast curing silicone polymer/resin composition having low compression set comprising:
- (a) a silicone component of the general formula;
space="preserve" listing-type="equation">MM.sup.vi QDwhereinM is R3 SiO1/2 ;
Mvi is CH2 ═
CHR12 R2 SiO1/2 ;
Q is SiO4/2 ; and
D is R2 SiO2/2,wherein the ratio of D units to Q units is from about 0.5;
1 to about 8;
1 and wherein the ratio of M and Mvi units is from 1.1 to about 2.0;
wherein each R is independently alkyl of from 1 to about 8 carbon atoms, cycloalkyl or cycloalkenyl of from 5 to about 10 carbon atoms or aryl of from 6 to about 12 carbon atoms;
R1 is alkylene of from 1 to about 10 carbon atoms and z is 0 or 1;
(b) a vinyl containing diorganopolysiloxane of the formula;
space="preserve" listing-type="equation">M.sup.vi D.sub.x M.sup.viwhere Mvi is as defined as above, D is as defined above, and x is an integer whereby the viscosity of Mvi Dx Mvi is from about 100 to about 200,000 centipoise at 25°
C.;
(c) from 0.1 to 50 parts per million of the total composition of a platinum catalyst; and
(d) from 0.1 to 25 parts by weight of a curing agent selected from the group consisting of hydrogen containing silanes and hydrogen containing polysiloxanes and mixtures thereof;
whereby the compression set of said composition is reduced by at least about 20%.
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Abstract
The present invention provides novel vinyl containing organopolysiloxane elastomers which possess excellent low compression set and heat aging characteristics and which can advantageously be formulated into liquid silicone elastomer moldable compositions.
25 Citations
21 Claims
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1. A fast curing silicone polymer/resin composition having low compression set comprising:
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(a) a silicone component of the general formula;
space="preserve" listing-type="equation">MM.sup.vi QDwherein M is R3 SiO1/2 ; Mvi is CH2 ═
CHR12 R2 SiO1/2 ;Q is SiO4/2 ; and D is R2 SiO2/2, wherein the ratio of D units to Q units is from about 0.5;
1 to about 8;
1 and wherein the ratio of M and Mvi units is from 1.1 to about 2.0;
wherein each R is independently alkyl of from 1 to about 8 carbon atoms, cycloalkyl or cycloalkenyl of from 5 to about 10 carbon atoms or aryl of from 6 to about 12 carbon atoms;
R1 is alkylene of from 1 to about 10 carbon atoms and z is 0 or 1;(b) a vinyl containing diorganopolysiloxane of the formula;
space="preserve" listing-type="equation">M.sup.vi D.sub.x M.sup.viwhere Mvi is as defined as above, D is as defined above, and x is an integer whereby the viscosity of Mvi Dx Mvi is from about 100 to about 200,000 centipoise at 25°
C.;(c) from 0.1 to 50 parts per million of the total composition of a platinum catalyst; and (d) from 0.1 to 25 parts by weight of a curing agent selected from the group consisting of hydrogen containing silanes and hydrogen containing polysiloxanes and mixtures thereof; whereby the compression set of said composition is reduced by at least about 20%. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification