Asahi Kasei Kogyo Kabushiki Kaisha

Tadashige Hata

Kazuhiko Matsuzaki

Junzo Masamoto

Sadao Ibe

Yukio Tanigawa

Hirohisa Morishita

Mikio Oka

Shiyuzi Yahiro

A polyacetal resin composition which comprises about 100 parts by weight of a polyacetal having a residual fluorine concentration of not more than about 13 ppm and a concentration of formaldehyde generated when the polyacetal is heated at about 230&deg; C. for about 30 minutes in nitrogen of not more than about 500 ppm; from about 0.01 to about 3 parts by weight of an antioxidant; and from about 0.001 to about 5 parts by weight of a basic substance. The above polyacetal resin composition is excellent in long-term thermal aging resistance under high-temperature circumstances.

Polyacetal resin composition excellent in aging resistance

Polyacetal resin composition

The present invention provides an acetal resin composition comprising:

Stabilized acetal resin compositions

Polyacetal copolymer and composition thereof

Thermoplastic graft copolymer and process for producing the same

A process for producing formaldehyde having high purity is disclosed, which comprises: (A) feeding crude formaldehyde containing water and methanol to the middle or lower part of a distillation column, and feeding a polyalkylene oxide compound which is inert to formaldehyde to the upper part of the column in an amount at least 10 times the total weight of the water and methanol contained in the crude formaldehyde; (B) carrying out distillation; and (C) recovering purified formaldehyde gas from the top of the column while withdrawing a solution containing the polyalkylene oxide compound, water and methanol from the bottom of the column. Using this process, formaldehyde having stable high purity can be obtained continuously through simplified steps at low cost.

Process for producing high purity formaldehyde

Growing community of inventors

Kurashiki, Japan

Tadashige Hata