Solventless or high solids-containing silicone pressure sensitive adhesive compositions
AssigneeGeneral Electric Company
InventorsShaow B. Lin, Jeffrey H. Wengrovius
Life of this patent
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Abstract
Solventless or low solvent-containing silicone pressure sensitive adhesive compositions having excellent adhesive strength and high tack are provided, comprising (A) a toluene-soluble resinous copolymer containing R.sub.3 SiO.sub.1/2 units and SiO.sub.4/2 units; (B) a vinyi-endblocked polydiorganosiloxane having a viscosity of 10 to 500 centipoise at 250.degree. C.; (C) a hydride-endblocked polydiorganosiloxane having a viscosity of 10 to 1,000 centipoise at 250.degree. C.; the ratio of silicon-bonded hydrogen atoms in (C) to olefinically unsaturated radicals in the total of (A) and (B), being in the range of from about 1.2:1 to about 15.0:1; and (D) a hydrosilation catalyst.
Claims30
An article of manufacture comprising a solid support carrying on at least one surface thereof an organopolysiloxane composition curable to produce a pressure sensitive adhesive having high tack and high peel adhesion, consisting essentially of by weight;
- (A) from about 50 to about 75 parts by weight of a toluene soluble, resinous copolymer comprising R.sub.3 SiO.sub.1/2 units and SiO.sub.4/2 units wherein R is a monovalent hydrocarbon radical having from 1 to about 6 carbon atoms, wherein the resinous copolymer comprises from about 0.2% to about 5.0% by weight, based on the total weight of the copolymer, of hydroxyl radicals, at least 95% of all R groups being an alkyl group, the total number of R radicals that are alkenyl radicals being 0-0.5% of all R radicals, the molar ratio of R.sub.3 SiO.sub.1/2 units to SiO.sub.4/2 units being from about 0.6 to about 0.9 inclusive;
- (B) an alkenyl-terminated polydiorganosiloxane having a viscosity of from about 10 to about 500 centipoise at 25.degree. C. and having the general formula
- R.sup.2 R.sup.1.sub.2 SiO(R.sup.3.sub.2 SiO).sub.m SiR.sup.1.sub.2 R.sup.2 ( 1)
- wherein each R.sup.1 is independently an alkyl group having from 1 to about 10 carbons atoms or an aryl group, R.sup.2 is an alkenyl group having from 1 to about 10 carbon atoms, each R.sup.3 is independently R.sup.1 or R.sup.2, with the proviso that at least 99.5% of all R.sup.3 radicals are R.sup.1, "m" is a number in the range of from about 1 to about 300;
- (C) a hydride-terminated organohydrogenpolysiloxane compatible with the mixture of (A) and (B) and having a viscosity of from about 10 to about 1,000 centipoise at 25.degree. C. and having the general formula
- R.sup.4.sub.2 HSiO(R.sup.5.sub.2 SiO).sub.a SiHR.sup.4.sub.2 ( 11)
- wherein each R.sup.4 is independently an alkyl group having from 1 to about 10 carbons atoms or an aryl group, and each R.sup.5 is hydrogen or R.sup.4, with the proviso that at least 99.5% of all R.sup.5 radicals are R.sup.4, "a" is a number in the range of from 1 to about 500, there being at least two silicon-bonded hydrogen atoms per molecule of (C), no silicon atom bearing more than one silicon-bonded hydrogen atom;
- the total of (B) and (C) being from about 25 to about 50 parts by weight;
- the total of (A), (B), and (C) being 100 parts by weight;
- the molar ratio of silicon-bonded hydrogen groups in (C) to silicon-bonded alkenyl groups in (A) and (B) being in the range of from about 1.2:1 to about 15.0:1;
- (D) a catalytic amount of hydrosilation catalyst;
- and
- (E) from 0 to about 40% by weight of an organic solvent.
A pressure sensitive adhesive tape comprising a flexible support carrying on at least one surface thereof an organopolysiloxane composition curable to produce a pressure sensitive adhesive having high tack and high peel adhesion, consisting essentially of weight;
- (A) from about 50 to about 75 parts by weight of a toluene soluble, resinous copolymer comprising R.sub.3 SiO.sub.1/2 units and SiO.sub.4/2 units wherein R is a monovalent hydrocarbon radical having from 1 to about 6 carbon atoms, wherein the resinous copolymer comprises from about 0.2% to about 5.0% by weight, based on the total weight of the copolymer, of hydroxyl radicals, at least 95% of all R groups being an alkyl group, the total number of R radicals that are alkenyl radicals being 0-0.5% of all R radicals, the molar ratio of R.sub.3 SiO.sub.1/2 units to SiO.sub.4/2 units being from about 0.6 to about 0.9 inclusive;
- (B) an alkenyl-terminated polydiorganosiloxane having a viscosity of from about 10 to about 500 centipoise at 25.degree. C. and having the general formula
- R.sup.2 R.sup.1.sub.2 SiO(R.sup.3.sub.2 SiO).sub.m SiR.sup.1.sub.2 R.sup.2 ( 1)
- wherein each R.sup.1 is independently an alkyl group having from 1 to about 10 carbon atoms or an aryl group, R.sup.2 is an alkenyl group having from 1 to about 10 carbon atoms, each R.sup.3 is independently R.sup.1 or R.sup.2 with the proviso that at least 99.5% of all R.sup.3 radicals are R.sup.1, "m" is a number in the range of from about 1 to about 300;
- (C) a hydride-terminated organohydrogenpolysiloxane compatible with the mixture of (A) and (B) and having a viscosity of from about 10 to about 1,000 centipoise at 25.degree. C. and having the general formula
- R.sup.4.sub.2 HSiO(R.sup.5.sub.2 SiO).sub.a SiHR.sup.4.sub.2 ( 11)
- wherein each R.sup.4 is independently an alkyl group having from 1 to about 10 carbon atoms or an aryl group, and each R.sup.5 is hydrogen or R.sup.4, with the proviso that at least 99.5% of all R.sup.5 radicals are R.sup.4, "a" is a number in the range of from 1 to about 500, there being at least two silicon-bonded hydrogen atoms per molecule of (C), no silicon atom bearing more than one silicon-bonded hydrogen atom;
- the total of (B) and (C) being from about 25 to about 50 parts by weight;
- the total of (A), (B), and (C) being 100 parts by weight;
- the molar ratio of silicon-bonded hydrogen groups in (C) to silicon-bonded alkenyl groups in (A) and (B) being in the range of from about 1.2:1 to about 15.0:1;
- (D) a catalytic amount of a hydrosilation catalyst;
- and
- (E) from 0 to about 40% by weight of an organic solvent.
Dependencies are inferred from the claim text.