Abstract: Hydrophilic monomers in a supercooled, transparent state, are polymerized in the presence of water. The polymers have low levels of residual monomers and exhibit good mechanical strength. The process provides materials useful as contact lenses.

Abstract: A mixture of a specified siloxanylalkyl ester monomer and a specified vinyl monomer is polymerized by exposure to an ionizing radiation at low temperatures and the resulting polymer is worked with a lathe cut to form a contact lens. The contact lens obtained is free from any optical distortion, has good dimensional stability and exhibits high oxygen permeability. In a preferred embodiment, a monomer mixture comprising a siloxanylalkyl ester, a methacrylate or acrylate, N-vinylpyrrolidone, and a small amount of a dimethacrylate or diacrylate is exposed to a total dose of 1.times.10.sup.5 -5.times.10.sup.6 roentgens at a low temperature (-80.degree. C. to -20.degree. C. and at a dose rate of 8.times.10.sup.4 -2.times.10.sup.6 roentgens per hour, and the resulting polymer is worked into a contact lens by a suitable forming process involving cutting, grinding and polishing operations.

Abstract: There is provided a polymer composition consisting essentially of 95-50 wt% of a methyl methacrylate homopolymer or copolymer component and 5-50 wt% of a cross-linked elastomer obtained by copolymerizing a mixture of stated amounts of (I) alkyl acrylate, (II) allyl acrylate and/or allyl methacrylate and (III) benzyl acrylate, the elastomer having a stated average particle size and a stated extent of cross-linking. The polymer composition comprises (1) a graft copolymer obtained by polymerizing methyl methacrylate or its mixture in the presence of the above elastomer; or (2) a blend of the above graft copolymer and a methyl methacrylate homopolymer or copolymer. The polymer composition provides shaped articles exhibiting good transparency over a broad range of temperature as well as good weather resistance and impact resistance.

Abstract: An improvement in a process for producing a synthetic resin cast article having an abrasion-resistant polymer surface layer integrated with the polymer body is provided. The improvement is characterized in that the abrasion-resistant polymer surface layer is formed by a two step polymerization procedure; in the first polymerization step, the polymerizable material is covered with a covering body such as a polymer film, closely adhered thereto, and in the second polymerization step, the polymerizable material is exposed to the air.