Mitsui Toatsu Chemicals, Incorporated

Noritoshi Ishida

Zunzi Tashima

Kazunari Nitta

Takashi Nagou

Naoki Sato

Hiroyuki Itoh

Kazuyuki Kuroda

Tatsuya Nagayoshi

Mitsunori Shimamatsu

Michiya Takasaki

Masaaki Iijima

Naoyuki Yano

Katsuyuki Nagamatsu

The hue of a methylene-crosslinked polyphenylene polyisocyanate continuously produced by the reaction with phosgene in an inert solvent of a polyamine mixture obtained by condensation of aniline and formaldehyde in the presence of an acid catalyst is improved by first removing any residual phosgene followed by heat treatment in the presence of hydrogen chloride gas.

Process for the production of methylene-crosslinked polyphenylene

A fractionation process of a methylene bridged polyphenylene polyisocyanate mixture obtained by phosgenating condensation product of aniline and formaldehyde is disclosed. In order to apply the above mixture to a variety of uses, the process separates the mixture into fractions by giving primary attention to the content of 4,4'-and 2,4'-isomer of diphenylmethane diisocyanate and at the same time reduces the content of impurities having acidity and hydrolyzable chlorine.

Fractionation process of reaction mixture containing methylene bridged

A methylene-crosslinked polyarylamine is disclosed which contains a less amount of N-methylmethylenedianiline. A process for continuously preparing this kind of methylene-crosslinked polyarylamine is also revealed which comprises reacting aniline with formalin in the presence of hydrochloric acid under specific reaction conditions.

Methylene-crosslinked polyarylamine and process for preparing same

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Ohmuta, Japan

Noritoshi Ishida