PRODUCTION OF DIPHENYLMETHANEDIISOCYANATE-BASED POLYISOCYANATE

Title:

PRODUCTION OF DIPHENYLMETHANEDIISOCYANATE-BASED POLYISOCYANATE

Document Type and Number:

Japanese Patent JPH0782230

Kind Code:

A

Abstract:

PURPOSE: To provide a producing method not only producing a MDI-based polyisocyanate which is not colored or remarkably reduced in coloring, but simultaneously capable of also preventing coloring during storage.

CONSTITUTION: In producing diphenylmethanediisocyanate-based polyisocyanate by subjecting a condensation product obtained by condensing aniline with formaldehyde in the presence of a catalyst or a diaminodiphenylmethane-based polyamine to phosgenation, this producing method is carried out by adding an organic phosphorous acid before carrying out phosgenation reaction. As necessary, the phosgenation product is separated into diphenylmethanediisocyanate and polyphenylenepolymethylenepolyisocyanate.

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PROCESS FOR PRODUCTION OF PYRAZINE DERIVATIVE, AND INTERMEDIATE FOR THE PRODUCTION

Inventors:

FUKUTOMI YORITO
YOKOYAMA TSUNEHIRO
AOKI YUSUKE

Application Number:

JP24966693A

Publication Date:

March 28, 1995

Filing Date:

September 13, 1993

Export Citation:

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Assignee:

NIPPON POLYURETHANE KOGYO KK

International Classes:

C07B61/00; C07C263/10; C07C265/14; C08G18/76; (IPC1-7): C07C265/14; C07C263/10

Attorney, Agent or Firm:

Oka Saki Hideo

Next Patent: AROMATIC DIURETHANE COMPOUND