Patent ID: 6699953
Filing Date: 2004-03-02
Classification: C08F,G02B

Abstract:
A lens comprising a synthetic resin, said synthetic resin being a copolymer obtained by copolymerizing a composition comprising:30 to 70% by weight of a bis-2-methacryloylthioethyl sulfide of the formula CH2&boxH;C(CH3)COSCH2CH2SCH2CH2SCOC(CH3)+CH2; 15 to 40% by weight of a bifunctional or multifunctional thiol; 15 to 40% by weight of a bifunctional (meth)acrylic compound [A]; and 0 to 75% by weight of a monomer copolymerizable with these compounds, wherein said lens has a refractive index of 1.58 or more, an Abbe's number of 35 or more and a specific gravity of 1.35 or less, and wherein said bifunctional (meth)acrylic compound [A] is one or more compounds selected from the group consisting of poly(ethylene glycol) di(meth)acrylate, poly(propylene glycol) di(meth)acrylate, poly(butylene glycol) di(methacrylate), neopentyl glycol di(meth)acrylate, neopentyl glycol di(meth)acrylhydroxypivalate, hexanediol di(meth)acrylate, 2-ethylpropanediol di(meth)acrylate, 2-butylpropanediol di(meth)acrylate, nonanediol di(meth)acrylate, 2-hydroxy- 1,3-dimethacryloxypropane, 2-hydroxy-1-acryloxy-3-methacryloxypropane, 2,2-bis(4-((meth)acryloxy-polyethoxy)phenyl)propane, di(meth)acryl isophthalate, di(meth)acryl terephthalate, bisphenol A polyepoxy-(meth)acrylate, 1,4-bis(meth)acryloylthiobenzene, and bisphenol F polyepoxy-(meth)acrylate.