Patent ID: 7834105

Claim:
A curable composition comprising: a polythioether; and a polybasic acid-based polyepoxy, wherein the polythioether is formed by the process of: reacting a first polythiol with a compound comprising one epoxy group and a second group, other than an epoxy group, which is reactive with a thiol group to form a first prepolymer, wherein the polythiol preferentially reacts with the second group; reacting the first prepolymer and a second polythiol with the epoxy group to form a second prepolymer; and reacting the second prepolymer and a third polythiol with a polyvinyl ether, and wherein the polythioether is chosen from a compound of Formula 1: R 6 -A-[—S—(CH 2 ) 2 —R 2 —(CH 2 ) 2 —S-A-] n -R 6 1 wherein A is chosen from a segment chosen from Formula 2(a) and Formula 2(b) wherein each R 1 is independently chosen from C 2-6 n-alkylene, C 3-6 branched alkylene, C 6-8 cycloalkylene, C 6-10 alkylcycloalkylene, —[—(CH 2 ) p —X—] q —(CH 2 ) r —, and —[—(CH 2 ) p —X—] q —(CH 2 ) r — in which at least one —CH 2 —group is substituted with at least one methyl group; wherein each X is independently chosen from O, S, —NH—, and —NR 3 —, wherein each R 3 is chosen from hydrogen and —CH 3 ; p is an integer from 2 to 6; q is an integer from 1 to 5; and r is an integer from 2 to 10; each R 2 is independently chosen from O, C 2-6 alkyleneoxy, and C 5-12 cycloalkyleneoxy, each R 4 is independently chosen from —CH 2 —CH 2 —and olefins conjugated with an electron attracting group; each R 5 is independently chosen from C 2-10 alkylene and C 2-10 alkyleneoxy; each R 6 is independently chosen from a thiol group, a hydroxyl group, an amine group, and a vinyl group; and n is an integer chosen to yield a number average molecular weight for the polythioether polymer ranging from 500 to 20,000 Daltons, wherein the weight ratio of the segment of Formula 2(a) to the segment of Formula 2(b) ranges from 2:1 to 3:1.