Mitsubishi Gas Chemical Company, Inc.

Isamu Masumoto

Masanori Furukawa

Toshikazu Umemura

Akira Okamura

Yukihiro Iha

Takahiro Nakamura

Akitoshi Sugio

Mutsuhiko Takeda

Takao Kawaki

Akira Amemiya

Tomotaka Furusawa

Katsumasa Tanaka

Daigo Nakaya

Zenpei Mizutani

Takeo Suzumori

Hiroyuki Urabe

Tadashi Kunii

Hiroshi Yada

Yoshihiro Ono

Atsuo Kuramoto

Yoshihito Hara

Tatsuhiko Kurihara

Akio Hasebe

Kaneo Yoshioka

Noriyasu Nakao

Kazumasa Maji

Mitsuo Nakagawa

Polyoxymethylene copolymer and molded article thereof

Process for producing oxymethylene copolymer

Acetal resin composition containing a terminal-etherified polyalkylene

An improved method of stabilizing a polyoxymethylene copolymer, which comprises

Method of stabilizing polyoxymethylene copolymer

A process for producing an oxymethylene copolymer by copolymerizing trioxane with at least one cyclic comonomer selected from the group consisting of cyclic ethers and cyclic formals, said process comprising

Process for producing oxymethylene copolyer

In a process for producing a stabilized oxymethylene copolymer by heat-melting, at a temperature ranging between the melting point of the copolymer and a temperature 100.degree. C. higher than the melting point in a degassing apparatus in the presence of a heat stabilizer, a crude oxymethylene copolymer of trioxane with a cyclic acetal or cyclic ether, to decompose and eliminate the instable portions of the copolymer, the improvement which comprises using as the degassing apparatus in heat stabilizing the crude oxymethylene copolymer a combination of (A) an extruder and (B) a surface renewing-type mixer, and carrying out the operation by first feeding a crude oxymethylene copolymer to said extruder (A) to heat-melt and decompose 30-90% by weight of the instable portions of the crude copolymer, removing the decomposed gas via a vent provided in said extruder, and thereafter introducing the molten resin continuously to said surface renewing-type mixer (B) where substantially all of the remaining instable portions of the oxymethylene copolymer are heat-decomposed until the content of the instable portions falls below about 2 wt. %, thereby heat stabilizing the copolymer; said extruder (A) having a single or a plurality of shafts, said surface renewing-type mixer functioning to mix and knead the resin thereby constantly renewing the surface of the resin to volatize the volatiles contained therein.

Process for heat stabilizing oxymethylene copolymers

A method for recovering polyphenylene oxide having a high bulk density and a reduced content of fine particles from a solution of a polyphenylene oxide, which comprises adding a non-solvent composed of a lower alkyl alcohol and water to an aromatic solvent solution of a polyphenylene oxide substantially free from impurities to precipitate the polyphenylene oxide, the weight ratio of the aromatic solvent to the lower alkyl alcohol being from 1:1 to 1:2 and the weight ratio of the lower alkyl alcohol to water being from 1:0.005 to 1:0.1 in the precipitation system, and the addition of the non-solvent being controlled such that a liquid composition of the aromatic solvent, the lower alkyl alcohol and water forms a single phase; and recovering the precipitated polyphenylene oxide.

Method for recovering polyphenylene oxides

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Yokkaichi, Japan

Isamu Masumoto