Mitsubishi Petrochemical Company Limited

Matsushita Electric Industrial Co., Ltd.

Tadao Takeyama

Mitsutoshi Aritomi

Takahiro Matsuo

Takao Inoue

Tadashi Sakairi

Kaoru Kanayama

Takeshi Nakato

Yoshinobu Ohnuma

Hiromi Chiba

A non-crystalline ether-imide type high purity bismaleimide composition represented by formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 each represent a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; R.sup.5 represents a hydrogen atom or a methyl group; and R.sup.6 represents a hydrogen atom, a methyl group or a phenyl group. The non-crystalline bismaleimide (I) has a purity of 95 wt % or higher, a melting point of not higher than 130.degree. C., and exhibits excellent solubility in a solvent. It is prepared by a process comprising uniformly melting a crystalline bismaleimide (I) followed by rapid cooling to solidify or a process comprising subjecting a maleamic acid, which is obtained by addition reaction between a corresponding aromatic ether diamine and maleic anhydride in an aromatic hydrocarbon/aprotic polar solvent mixed solvent, to dehydrating cyclization in the presence of an acid catalyst while azeotropically removing by-produced water with the aromatic hydrocarbon solvent, removing the remaining aromatic hydrocarbon solvent by distillation, withdrawing the produced maleimide in a molten state, and rapidly cooling to solidify.

Non-crystalline ether-imide type high purity bismaleimide composition

An optical resin consisting essentially of a radical polymerization polymer of an ethylenically unsaturated monomer, characterized in that at least a major part of the ethlenically unsaturated monomer is an ester of 1 mole of tricyclo[5,2,1,0.sup.2,6 ]decanedimethanol with 2 moles of a mixture of acrylic acid and metharcylic acid. Because the resin is a polymer obtained from the restricted monomer as specified above, the resin possesses high thermal resistance and high heat stability as well as low hygroscopic property. Dimethanol compounds from higher Diels-Alder adducts of cyclopentadine are also used in place of the tricyclo [5,2,1,0.sup.2,6 ]decanedimthanol which is a Diels-Alder adduct of two moles of cyclopentadiene.

Optical disc and method of manufacturing the same

A method for producing a plastic substrate having Tg of 110.degree. C. or more is disclosed, which comprises radical polymerizing a polyfunctional (meth)acrylate compound in a mold by a cast molding method, removing the resulting substrate from the mold when the glass transition temperature of the substrate reaches 10.degree. to 100.degree. C., and then post-curing the substrate. The method of the present invention can provide high quality plastic substrates with high productivity.

Method for cast molding plastic substrate

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Ami, Japan

Tadao Takeyama