Toughening agent for epoxy resin compositions

United States Patent（美国专利号）：8927677

Abstract： A curable epoxy resin composition comprising (a) a liquid epoxy resin; (b) at least one curing agent selected from the group consisting of at least one anhydride; at least one phenolic novolac; at least one amine; or a mixture thereof; and (c) at least one high molecular weight poly(propylene oxide) polyol having the following chemical structure: ##STR00002## wherein the number average molecular weight of the poly(propylene oxide) polyol is about 7,000 to about 20,000 with n being from about 120 to about 345.