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Title:
METHOD FOR PRODUCING METHYLENE-CROSSLINKED POLYPHENYLENE POLYISOCYANATE
Document Type and Number:
Japanese Patent JP2006057073
Kind Code:
A
Abstract:

To provide a method for producing a methylene-crosslinked polyphenylene polyisocyanate with simply and effectively suppressing discoloration of the same.

The method is to react a polyamine mixture generated by condensation reaction of aniline with formaldehyde in the presence of an acid catalyst with phosgene in the presence of an inactive solvent and produce the methylene-crosslinked polyphenylene polyisocyanate. In the method, (1) after the phosgenation reaction, remaining phosgene is removed from the obtained reaction mixture containing crude methylene-crosslinked polyphenylene polyisocyanate, subsequently (2) an OH-having aromatic compound having a carboxy group at the ortho-position and expressed by formula (I) (wherein R1, R2, R3 and R4 express each independently H or a 1-6C hydrocarbon group) is added to the crude methylene-crosslinked polyphenylene polyisocyanate and the mixture is treated by heating the same.


Inventors:
KOKADO KAZUHIRO
SHIMAMOTO MASASHI
SAEKI TAKUYA
IZUKAWA TSUKURU
Application Number:
JP2004340742A
Publication Date:
March 02, 2006
Filing Date:
November 25, 2004
Export Citation:
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Assignee:
MITSUI TAKEDA CHEMICALS INC
International Classes:
C08G18/76; C07C263/10; C07C265/14
Domestic Patent References:
JPH09100263A1997-04-15
JPH04253952A1992-09-09
JPH0782230A1995-03-28
JP2006057072A2006-03-02
Attorney, Agent or Firm:
Shunichiro Suzuki
Koji Makimura
Chihata Takahata
Toru Suzuki