Mitsui Toatsu Chemicals, Incorporated

Akira Ibi

Akihiro Yamaguchi

Shoji Tamai

Koichi Takeuchi

Etsuo Ohkawado

Shigeyuki Shishido

Shigeru Takahashi

Takushi Sato

Yoshihiro Nodate

Toshimi Ogata

Masanori Kitagawa

Takayuki Kageyama

Eiichi Sagawa

Hisai Nakajima

A purification process of crude methacrylamide by recrystallization from an aqueous methacrylamide solution, comprising the steps of conducting crystallization by adjusting the hydrogen ion concentration of the aqueous methacrylamide solution to pH 8 or more, separating a methacrylamide crystal, adjusting 5% by weight or more of resulting mother liquor to pH 5 or less, separating precipitated insoluble matter, and reusing thus-treated mother liquor, is provided. The high quality methacrylamide crystal thus obtained is excellent in Hazen number, purity and transparency of a methanol solution and suitable for uses such as windshield glasses.

Purification process of methacrylamide

A process for the preparation of an N-substituted unsaturated carboxylic acid amide represented by the following formula: ##STR1## wherein R.sup.1 means a hydrogen atom or methyl group Y denotes a methylene group, oxygen atom or methylimino group, m and n stand individually for an integer of 0 to 5, and m+n is an integer of 3 to 5. The process comprises reacting a specified .beta.-alkoxy-substituted carboxylate with a specified cyclic amine to form a .beta.-alkoxy-substituted carboxylic acid amide compound and then removing an alcohol from the carboxylic acid amide compound in the presence of a basic catalyst to form an unsaturated group.

Preparation process of unsaturated carboxylic acid amide

This invention relates to a polyimide powder in use for adhesion and/or coat forming and to a method of preparing said powder, wherein polyamic-acid is chemically imidized which is obtained by reacting tetracarboxylic acid dianhydride with diamine in organic solvents. This invention further relates to a method for adhesion and coat forming by using said polyimide powder. This invention still further relates to a method for preparing prepreg by using said polyimide powder, and a method for adhesion and preparing molded laminates by using said prepreg.

Polyimide adhesives, coats and prepreg

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Mobara, Japan

Akira Ibi