Mitsui Chemicals, Inc.

Yasushi Kotaki

Masanobu Ajioka

Masatoshi Takagi

Shinji Ogawa

Masayuki Sakai

Shoji Hiraoka

Hiroshi Suizu

Yuji Terado

Hiroyuki Suzuki

Ryo Shinagawa

Hiroshi Kimura

Hiroshi Takeuchi

Koji Takamatsu

Yoshiki Shimokawatoko

Takashi Kanno

Koichi Murayama

A method for producing toluenedicarbamate includes a carbamate production process of producing toluenedicarbamate by reaction between toluenediamine, urea, and/or N-unsubstituted carbamic acid ester, and alcohol; and a benzoyleneurea reduction process of reducing a disubstituted benzoyleneurea and a derivative thereof to 10 mol or less relative to 100 mol of toluenedicarbamate, wherein the disubstituted benzoyleneurea is represented by formula (1) below and has a methyl group and an amino group: 

Method for producing toluenedicarbamate, method for producing toluenediisocyanate, and toluenedicarbamate

The invention relates to a process for producing an aliphatic polyester excellent in stability which includes subjecting an aliphatic polyester containing at least 50% of an aliphatic hydroxycarboxylic acid unit, obtainable by solid-phase polymerization under a flowing gas in the presence of a volatile catalyst so as to have a desired weight average molecular weight within the range of 50,000 to 1,000,000, to a heat treatment at a temperature equal to or higher than the reaction temperature of the solid-phase polymerization under a flowing gas with maintaining the aliphatic polyester in a solid state. According to the process of the invention, an aliphatic polyester excellent in stability at molding and storage stability is obtained.

Process for producing aliphatic polyester excellent in stability

A process for producing aliphatic polyester wherein a crystallized aliphatic polyester prepolymer formed from an aliphatic dihydric alcohol and an aliphatic dicarboxylic acid and having a weight-average molecular weight of 2,000 to 100,000 is caused to undergo solid-phase polymerization in the presence of a volatile catalyst to make an aliphatic polyester having a weight-average molecular weight of 50,000 to 1,000,000. This process is more efficient than any prior process calling for a complicated step for catalyst removal, since it enables the removal of the catalyst from the reaction system during and/or after solid-phase polymerization. The polyester is comparable in stability to any aliphatic polyester having any catalyst removed therefrom.

Process for preparing aliphatic polyester

The invention provides a process for producing high-molecular aliphatic polyesters capable of being substitutes for general-purpose resins that are required to have high toughness, in a simplified manner and at a high volume efficiency. Specifically, in the process, used as the starting material is an easily-available, low-molecular aliphatic polyester prepolymer to be prepared through polycondensation of inexpensive materials of an aliphatic hydroxycarboxylic acid such as lactic acid, glycolic acid or the like, an aliphatic polyalcohol such as butanediol or the like, and an aliphatic polycarboxylic acid such as succinic acid or the like, and the starting prepolymer is crystallized and thereafter polycondensed in a solid phase in the presence of a catalyst to give the intended, tough and high-molecular aliphatic polyester.

Preparation process of polyester

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Fukuoka, Japan

Yasushi Kotaki