Mitsubishi Gas Chemical Company, Inc.

Mitsubishi Gas Chemical, Inc.

Tadashi Kawabata

Masahiro Kurokawa

Shojiro Kuwahara

Nobuyuki Koike

Takeshi Hirokane

Tsuyoshi Ikeda

Koshi Koide

Shin-ichi Hieda

Shojiro Kuwabara

The present invention relates to a polyester film produced by melt-extruding a polyester composed of a dicarboxylic acid unit and a diol unit, wherein 1 to 80 mol % of the diol unit is a unit containing a cyclic acetal skeleton, and the polyester film has an in-plane retardation of 20 nm or less at a wavelength of 550 nm. The polyester film is an optically isotropic polyester film which is easily produced by an extrusion-molding method and has an economical advantage. The polyester film is useful for production of optical members or optical products such as phase difference films, protective films for polarizing plates, light diffusion films, lens sheets, anti-reflection films and optical information recording media.

Polyester film, process for producing the same and use thereof

Disclosed is an acrylic syrup containing a vinyl monomer (A) of methyl methacrylate and a polymerized solid component (B) which is a high polymer of said vinyl monomer and has a weight average molecular weight of from 30,000 to 2,000,000 as measured by the GPC and a viscosity at 25&#xb0; C. of from 0.1 to 50 Pa&#xb7;s, wherein at least part of said polymerized solid component (B) is a grafted rubber obtained by graft-polymerizing said vinyl monomer with a rubbery polymer, and said grafted rubber has a large branching coefficient. The acrylic resin molded articles obtained from the acrylic syrup exhibit excellent impact resistance.

Acrylic syrup and method of producing the same

Acrylic syrup and method of producing same

A methyl methacrylate syrup is produced by the steps of (1) preparing a starting material comprising methyl methacrylate or a monomer mixture mainly comprising methyl methacrylate, and dividing the starting material into 20 to 70% by weight of an initial charge and 30 to 80% by weight of an after-charge; (2) heating the initial charge in a reactor; (3) adding a whole protion of a chain transfer agent at the time when the initial charge reaches a reaction temperature; (4) adding the after-charge over 0.1 to 10 hours together with a polymerization initiator having a half-life of 10 to 300 seconds at the reaction temperature; (5) continuing the heating after the addition of the after-charge and the polymerization initiator is complete; and (6) adding a hindered phenol polymerization inhibitor at the time the heating is finished. The methyl methacrylate syrup thus produced is excellent in storage stability.

Methyl methacrylate syrup and production thereof

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Kanagawa-ken, Japan

Tadashi Kawabata