Polyphenyl-polymethylene-polyisocyanate mixtures

Details Polyphenyl-polymethylene-polyisocyanate mixtures Polyphenyl-polymethylene-polyisocyanate mixtures

1976-11-01

1978-10-03

Torrence, Dolph H.

Chemistry of carbon compounds

Miscellaneous organic carbon compounds

C-metal

260 338UB, 260453SP, 203 89, 521160, 528 44, C07C119048

Patent

active

041184106

ABSTRACT:
Organic higher functional polyisocyanates are obtained by separating a mixture containing isomers of diphenylmethane diisocyanate and higher functional polyisocyanates having more than two benzene rings. The mixture is distilled under vacuum at a pressure of between 10.sup.-3 and 10.sup.-1 mm/Hg. under conditions which avoid chemical change in the organic polyisocyanates contained in the mixture. The polyisocyanates are separated into two fractions with a desired first fraction containing said higher functional polyisocyanates with only a trace of the isomers which is less than about 6% of the weight of the first fraction and having a viscosity of more than 10,000 cp/25.degree. C. The second fraction consists essentially of said isomers and can be further purified by crystallization.

REFERENCES:
patent: 2683730 (1954-07-01), Seeger et al.
patent: 3471543 (1969-10-01), Sayigh
patent: 3542871 (1970-11-01), Thompson
Canzler, Booklet "Rotafilm Dunnschichtverdampfer".
Saunders et al., "Polyurethanes, Chemistry and Technology", Part II, p. 610 (1964).

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