Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Patent
1982-09-20
1983-12-20
Lee, Lester L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
528 52, 528 53, 528 54, 528 55, 528 73, 528 84, C08G 7310
Patent
active
044219059
ABSTRACT:
The process described herein comprises the preparation of polyimides by the reaction of aromatic dianhydrides and aromatic diisocyanates in the presence of a metal acetylacetonate, such as Al, Co, Fe, Ni, Zr, etc. By using appropriate proportions, the polyimides may be end-capped with either anhydride or isocyanate groups. The use of the acetylacetonate permits the use of lower temperatures for imide ring closure thereby avoiding undesirable coreaction between anhydride groups and certain solvents. "Polyimide dianhydride" is an anhydride-terminated polyimide; and "polyimide diisocyanate" is an isocyanate-terminated polyimide as represented by the respective formulas: ##STR1## wherein Ar', Ar and n are as defined hereinafter. By this process, the polyimide dianhydride product has an anhydride activity of at least 0.17 as defined herein regardless of the type of solvent used.
REFERENCES:
patent: 3682860 (1972-08-01), Yoda et al.
patent: 3997513 (1976-12-01), Noda et al.
patent: 4094864 (1978-06-01), Onder
Lee Lester L.
Monacelli Walter J.
Plastics Engineering Company
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