Asahi Kasei Kogyo Kabushiki Kaisha

Asahi Kasei Kabushiki Kaisha

Kimio Imaizumi

Itaru Natori

Kiyoo Kato

Hiroshi Miyazawa

Satoshi Hashimoto

Keitaro Ameyama

Ikuji Ohtani

Toshinori Koseki

Kazuhiro Hosoya

Masatoshi Ikemi

Koichiro Azuma

Hideyuki Yamagishi

Satoru Kaji

A separator for electricity storage devices which comprises: a base comprising a porous film; and a thermoplastic polymer arranged on at least one surface of the base. The thermoplastic polymer has a dispersion (&#x3c3;), defined by the following numerical equation using the areas (Si) of Voronoi polygons obtained by Voronoi tessellation, of 0.01-0.7. (In the equation, Si is the measured area of each Voronoi polygon, m is an average of the measured areas of the Voronoi polygons, and n is the total number of the Voronoi polygons).

Separator for electricity storage device

Resin composition

Polymer containing a modified cyclic monomer unit

Polymeric composite material

The methacrylic copolymer of the present invention is a novel copolymer having low moisture absorption properties which comprises specific proportions of methyl methacrylate units and tert-butylcyclohexyl methacrylate units, optionally with specific ethylenically unsaturated compound units copolymerizable with the above-mentioned monomer units. The copolymer of the present invention is excellent not only in colorlessness, transparency, moldability, low double refraction and heat stability but also in low moisture absorption properties and heat resistance and, therefore, is suitable for use as a material for shaped articles, such as an optical element substrate and a light transmissible extruded plate, and can particularly advantageously be used for applications, such as an optical disc substrate.

Methacrylic copolymer having low moisture absorption properties

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

Growing community of inventors

Kiyose, Japan

Kimio Imaizumi