Patent ID: 7906563

Claim:
A polysiloxane-based prepolymer of a three-dimensional network structure produced by hydrolysis-condensation of a first mixture, said first mixture comprising: (a) a tetra-alkoxysilane compound having the following formula (I): wherein R 11 , R 12 , R 13 , and R 14 are independently a C 1 -C 8 alkyl group; (b) an ethylenically unsaturated organosiloxane monomer having the following formula (II): wherein R 21 , R 22 , and R 23 are independently a C 1 -C 6 alkyl group, and R 24 is a C 1 -C 6 alkyl group, a cyano group, or hydrogen, and X is a C 1 -C 4 alkylene, a single bond, (c) a hydrophilic silicon-containing polyfunctional monomer having the following formula (III): wherein Y is a C 2 -C 4 alkylene group, Z 1 and Z 2 independently represent a single bond or a C 1 -C 4 alkylene group, R 31 , R 32 , R 33 , R 34 , R 35 , and R 36 independently represent a C 1 -C 6 alkyl group, and d is an integer ranging from 3 to 90.