Asahi Kasei Kogyo Kabushiki Kaisha

Kazuhiro Hosoya

Makoto Honda

Jiro Kurita

Kohe Ozawa

Ikuji Ohtani

Kimio Imaizumi

Optical materials having well balanced properties such as high heat resistance, low hygroscopicity and low double refractivity. The optical materials are derived from a low hygroscopic, random copolymer comprising units of methacrylic acid and ester derivatives, and units of a six-membered ring acid anhydride.

Low-hygroscopic copolymer

An acrylic resin having an intrinsic viscosity [.eta.] of about 0.028 to about 0.117 l/g and a weight-average molecular weight to number-average molecular weight ratio (Mw/Mn), measured by gel permeation chromatography of about 2.3 to about 6.0, said resin comprising the polymerization product of (1) about 50 to 100 wt. % of methyl methacrylate and (2) 0 to about 50 wt. % of at least one monomer selected from the group consisting of acrylic ester monomer and methacrylic ester monomer, said acrylic ester monomer comprising the reaction product of an alkyl alcohol having 1 to 8 carbon atoms and acrylic acid and said methacrylic ester comprising the reaction product of an alkyl alcohol having 2 to 12 carbon atoms and methacrylic acid.

Acrylic resin having excellent solvent resistance and moldability

An acrylic resin having resistance to crazing or crack formation when brought into contact with an organic solvent may be prepared by polymerizing or copolymerizing a monomer or monomers comprising (1) 50 to 100 wt. % of methyl methacrylate and (2) 0 to 50 wt. % of at least one monomer selected from the group consisting of an acrylic ester and a methacrylic acid ester, and adding a chain transfer agent after initiation and prior to completion of the polymerization. The acrylic resins have an intrinsic viscosity of 0.028 to 0.117 liters per gram, and a ratio of weight-average molecular weight to number-average molecular weight of 2.3 to 6.0.

Solvent resistent acrylic resin and process for producing the same

A novel three-component type acrylic resin composition comprising a C.sub.3 -C.sub.8 alkyl ester of acrylic acid, methyl acrylate and methyl methacrylate in a specific ratio. Such composition can be readily molded into a shaped article which is excellent in solvent resistance even upon being fabricated. The composition of the present invention is also featured by its good heat distortion temperature and mechanical strength, as compared to the conventional acrylic resin composition.

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Tokyo, Japan

Kazuhiro Hosoya