Patent ID: 6235832
Filing Date: 2001-05-22
Classification: C08G,C08L

Abstract:
A RTV silicone composition curable in the presence of moisture, comprising(A) 0 to about 85 weight percent polydiorganosiloxanes comprising on average at least 1.2 chain terminations per molecule selected from the group consisting of hydroxysilyl groups described by formula--SiR.sup.2.sub.2 OH, (I)and alkoxysilyl groups described by formula--Z.sub.y --SiR.sup.2.sub.x (OR.sup.3).sub.3-x, (II)where each R.sup.2 is independently selected from the group consisting of a hydrogen atom and monovalent hydrocarbon radicals comprising 1 to about 18 carbon atoms, each R.sup.3 is an independently selected alkyl radical comprising 1 to about 8 carbon atoms, each Z is independently selected from the group consisting of divalent hydrocarbon radicals comprising about 2 to 18 carbon atoms and a combination of divalent hydrocarbon radicals and siloxane segments described by formula ##STR17##where R.sup.2 is as defined above, each G is an independently selected divalent hydrocarbon radical comprising about 2 to 18 carbon atoms, and c is a whole number from 1 to about 6, x is 0 or 1, and y is 0 or 1;(B) about 10 to 95 weight percent polydiorganosiloxanes comprising on average at least 1.2 chain terminations per molecule selected from the group consisting of hydroxysilyl groups, alkoxysilyl groups, and multi-alkoxysilyl groups described by formula--Z.sub.b --R.sup.4 (Z--SiR.sup.2.sub.n (OR.sup.3).sub.3-n).sub.a (III)provided that at least one chain termination per molecule comprises a multi-alkoxysilyl group, where R.sup.2, R.sup.3, and Z are as defined above, R.sup.4 is independently selected from the group consisting of a silicon atom and a siloxane radical comprising at least two silicon atoms and each Z is bonded to a silicon atom of R.sup.4 with the remaining valences of the silicon atoms of R.sup.4 being bonded to a hydrogen atom, a monovalent hydrocarbon radical comprising 1 to about 18 carbon atoms, or forming siloxane bonds, n is 0, 1, or 2, a is at least 2, and b is 0 or 1, provided, when b is 0, R.sup.4 is bonded to the polydiorganosiloxane through a siloxane bond;(C) an effective amount of a condensation catalyst;(D) 0 to about 40 weight percent of an alkoxysilane described by formulaR.sub.z Si(OR.sup.1).sub.4-z,where each R is an independently selected monovalent hydrocarbon radical comprising 1 to about 18 carbon atoms, each R.sup.1 is an independently selected alkyl radical comprising 1 to about 6 carbon atoms, and z is 0, 1, or 2; and(E) 0 to about 60 weight percent of a filler;provided that the sum of the weight percents of Components (A) and (B) comprises about 20 to 95 weight percent based on the total weight of the RTV silicone composition.