Patent ID: 8576471
Filing Date: 2013-11-05
Classification: B29D,C08F,G02B

Abstract:
1. A casting composition for producing photochromic optical elements, the composition including: (i) an acrylate or methacrylate monomer, (ii) a photochromic compound, (iii) a terpinolene-based radical chain transfer agent, and (iv) a thermal free radical initiator, wherein the casting composition is a liquid and wherein the acrylate or methacrylate monomer includes a combination of a urethane acrylate or methacrylate monomer and at least one of: (a) a relatively hard polymer formed from a polyalkylene oxide acrylate or methacrylate monomer; and a relatively flexible polymer formed from a polyalkylene oxide acrylate or methacrylate monomer; or (b) a relatively flexible polymer formed from a polyalkylene oxide acrylate or methacrylate monomer; a polypropylene glycol acrylate or methacrylate monomer; a lauryl acrylate or methacrylate monomer; or a isostearyl acrylate or methacrylate monomer; and a relatively hard polymer formed from a bisphenol A ethoxylated diacrylate or methacrylate.