US 5,705,588 A · Organopolysiloxane compositions which can be crosslinked to give elastomers

Abstract

New organopolysiloxane masses cross-linkable into elastomers by radical formation containing (1) high-viscosity diorganopolysiloxanes with a value equal to at least 3000 Nm, (2) low-viscosity vinyl-containing organopolysiloxanes having 20 to 1.10.sup.6 mPa.multidot.s at 25.degree. C. consisting of siloxane units (M units) having the formulae R.sup.1 R.sub.2 SiO.sub.1/2 and/or R.sub.3 SiO.sub.1/2, of siloxane units (D units) having the formulae R.sup.1 RSiO and/or R.sub.2 SiO and optionally HRSiO, and of siloxane units (T or Q units) having the formulas RSiO.sub.3/2 and/or R.sub.1 SiO.sub.3/2 and/or SiO.sub.2, in which R stands for a monovalent, possibly substituted hydrocarbon residue with 1 to 18 hydrocarbon atoms and R.sub.1 stands for a vinyl residue, provided that the organopolysiloxanes contain at least 1.0% by weight Si-bound vinyl groups; as well as (3) fillers.

Claims18

Dependent claims

In a composition containing fillers which is crosslinkable by means of free radical formation to give elastomers said composition comprising an organopolysiloxane admixture, the improvement comprising selecting as said organopolysiloxane admixture an organopolysiloxane admixture consisting of:

(1) high-viscosity diorganopolysiloxanes having a value of at least 3000 Nm determined in a Brabender Plastograph at 23.degree. C. and 60 revolutions per minute;
and
(2) low-viscosity vinyl-containing organpolysiloxanes having an average viscosity of 20 to 1.times.10.sup.6 mPa.multidot.s at 25.degree. C., consisting of (a) siloxane units selected from the group consisting of the formulae R.sup.1 R.sub.2 SiO.sub.1/2, R.sub.3 SiO.sub.1/2, and mixtures thereof;
(b) siloxane units selected from the group consisting of the formulae R.sup.1 RSiO, R.sub.2 SiO, and mixtures thereof;
and (c) siloxane units selected from the group consisting of the formulae RSiO.sub.3/2, R.sup.1 SiO.sub.3/2, SiO.sub.2, and mixtures thereof;
in which
R is a monovalent, unsubstituted or halogen- or cyano-substituted hydrocarbon radical having 1 to 18 carbon atoms per radical and
R.sup.1 is a vinyl radical,
with the proviso that the organopolysiloxanes contain at least 1.0% by weight of Si-bonded vinyl groups.

6 more elements

An organopolysiloxane composition which is crosslinkable by means of free radical formation to give elastomers, comprising:

(1) high-viscosity diorganopolysiloxanes having a value of at least 3000 Nm determined in a Brabender Plastograph at 23.degree. C. and 60 revolutions per minute;
(2) low-viscosity vinyl-containing organopolysiloxanes having an average viscosity of 20 to 1.times.10.sup.6 mPa.multidot.s at 25.degree. C., consisting of (a) siloxane units selected from the group consisting of the formulae R.sup.1 R.sub.2 SiO.sub.1/2, R.sub.3 SiO.sub.1/2, and mixtures thereof;
(b) siloxane units selected from the group consisting of the formulae R.sup.1 RSiO, R.sub.2 SiO, and mixtures thereof, optionally further containing HRSiO units;
and (c) siloxane units selected from the group consisting of the formulae RSiO.sub.3/2, R.sup.1 SiO.sub.3/2, SiO.sub.2, and mixtures thereof;
in which
R is a monovalent, unsubstituted or halogen- or cyano-substituted hydrocarbon radical having 1 to 18 carbon atoms per radical and
R.sup.1 is a vinyl radical,
with the proviso that the organopolysiloxanes contain at least 1.0% by weight of Si-bonded vinyl groups, and
(3) fillers
wherein said low viscosity vinyl-containing organopolysiloxane comprises siloxane units (a), siloxane units (b), and T siloxane units selected from the group consisting of RSiO.sub.3/2, R.sup.1 SiO.sub.3/2, and mixtures thereof, wherein the mol ratio of said T siloxane units to said siloxane units (a) is from about 1:5 to about 1:100;
and the mol ratio of said T siloxane units to said siloxane units (b) is from about 1:100 to about 1:300.

8 more elements

An organopolysiloxane composition which is crosslinkable by means of free radical formation to give elastomers, comprising:

(1) high-viscosity diorganopolysiloxanes having s value of at least 3000 Nm determined in a Brabender Plastograph at 23.degree. C. and 60 revolutions per minute;
(2) low-viscosity vinyl-containing organopolysiloxanes having an average viscosity of 20 to 1.times.10.sup.6 mPa.multidot.s at 25.degree. C., consisting of (a) siloxane units selected from the formulae R.sup.1 R.sub.2 SiO.sub.1/2, R.sub.3 SiO.sub.1/2, and mixtures thereof;
(b) siloxane units selected from the formulae R.sup.1 RSiO, R.sub.2 SiO, and mixtures thereof;
and (c) siloxane units selected from the formulae RSiO.sub.3/2, R.sup.1 SiO.sub.3/2, SiO.sub.2, and mixtures thereof;
in which
R is a monovalent, unsubstituted or substituted hydrocarbon radical having 1 to 18 carbon atoms per radical and
R.sup.1 is a vinyl radical,
with the proviso that the organopolysiloxanes contain at least 1.0% by weight of Si-bonded vinyl groups, and
(3) fillers,
wherein said low viscosity vinyl-containing organopolysiloxane comprises siloxane units (a), siloxane units (b), and Q siloxane units of the formula SiO.sub.2, wherein the mol ratio of Q siloxane units to siloxane units (a) is from about 1:5 to about 1:100;
and the mol ratio of Q siloxane units to siloxane units (b) is from about 1:100 to about 1:300.

8 more elements

Dependencies are inferred from the claim text.

Organopolysiloxane compositions which can be crosslinked to give elastomers

Life of this patent

Organopolysiloxane compositions which can be crosslinked to give elastomers

Life of this patent

Abstract

Claims18