Hydroxyl terminated polyfunctional epoxy curing agents

Claim 1

A polyfunctional phenolic hydroxyl terminated hardener product, useful in the curing of epoxy resins, which is the reaction product of (a) a polyglycidyl compound of the formula I, II, III or IV, ##STR20## wherein T 1 is 1,2-phenylene, 1,3-phenylene, 1,4-phenylene or ##STR21## where Q is alkylene of 1 to 6 carbon atoms, alkylidene of 2 to 6 carbon atoms, --SO 2 --, --SO--, --S--, --S--S--, --O-- or --CO--, T 2 is 1,2-phenylene, 1,3-phenylene or 1,4-phenylene, T 3 is 1,2,3-benzenetriyl, 1,2,4-benzenetriyl, 1,3,5-benzenetriyl or ##STR22## T 4 is ##STR23## where G 1 and G 2 are independently alkyl of 1 to 6 carbon atoms or are together alkylene of 4 to 5 carbon atoms, and (b) a diglycidyl compound of the formula glycidyl--O--E--O--glycidyl where E is 1,2-phenylene, 1,3-phenylene, 1,4-phenylene or ##STR24## where L is a direct bond, alkylene of 1 to 6 carbon atoms or alkylidene of 2 to 6 carbon atoms, wherein the ratio of equivalents of polyglycidyl compound (a) to diglycidyl compound (b) is from 1 to 4 to 1 to 1, with (c) a bisphenol of the formula HO--E.sub.1 --OH where E 1 has the same definitions as E, but is independent of E, wherein the ratio of equivalents of bisphenol component (c) to the total equivalents of glycidyl compounds (a) plus (b) is from 1.8 to 1 to 2.4 to 1, and where each glycidyl group is effectively endcapped with a moiety containing a free phenolic hydroxyl group by reaction of components (a) and (b) with (c) in the presence of an effective amount of a catalyst for promoting said reaction at a temperature between 120° and 300° C.