Patent ID: 8383744
Filing Date: 2013-02-26
Classification: B29D,C08F,G02B

Abstract:
1. An actinically crosslinkable prepolymer, which is a RAFT polymerization product of a reactive mixture comprising a polysiloxane crosslinker with two terminal vinyl-groups, a hydrophilic vinylic monomer, a RAFT agent, and a free-radical initiator, wherein the prepolymer comprises: (1) polysiloxane crosslinking units derived from the polysiloxane crosslinker both the two terminal vinyl-groups of which undergo the RAFT polymerization; (2) hydrophilic units derived from a hydrophilic vinylic monomer; (3) dangling polysiloxane chains each with one terminal vinyl group, wherein the dangling polysiloxane chains are derived from the polysiloxane crosslinker one of the two terminal vinyl-groups of which undergoes the RAFT polymerization while the other remains unreacted, wherein the molar ratio of the RAFT agent to the polysiloxane crosslinker in the reactive mixture is from about 0.005 to about 0.1, wherein the prepolymer is capable of being actinically crosslinked, in the absence of one or more vinylic monomers, to form a silicone hydrogel material.