Back to results
US 4,731,431 AGranted
Co-oligomerization product of a mixed cyanate and a polymaleimide
AssigneeThe Dow Chemical Company
InventorRobert E. Hefner, Jr.
Life of this patent
Estimating the term…
Abstract
Hydroxyaromatic oligomers are prepared by (I) reacting (A) an aromatic hydroxyl-containing material such as bisphenol A with (B) a cyanogen halide such as cyanogen bromide in the presence of a base such as triethylamine and (II) co-oligomerizing the cyanate-containing product from (I) with (C) a polymaleimide such as the reaction product of maleic anhydride with methylenedianiline optionally in the presence of (D) a co-oligomerization catalyst such as cobalt naphthenate. These oligomers are useful in the preparation of epoxy resins.
Claims3
The hydroxyaromatic oligomer composition resulting from
- (I) reacting at a temperature and time sufficient to essentially complete the reaction of
- (A) at least one material having an average of more than one aromatic hydroxyl group per molecule with
- (B) at least 0.01 but not more than 0.95 moles of at least one cyanogen halide per aromatic hydroxyl group;
- in the presence of
- (C) from about 0.01 to about 1.1 moles of a suitable base per aromatic hydroxyl group contained in component (A);
- and thereafter recovering the resultant cyanate-containing mixture;
- and
- (II) co-oligomerizing at a temperature and for a time sufficient to essentially complete the co-oligomerization reaction the cyanate-containing product from (I) with
- (D) a polymaleimide in an amount which provides a mole ratio of maleimide groups to cyanate groups of from about 0.01:1 to about 1:1;
- in the absence of or in the presence of
- (E) a suitable co-oligomerization catalyst.
8 more elements
Dependencies are inferred from the claim text.