Process for preparation of a phenolic-polybutadiene-HCHO resin composition useful for laminated sheet

摘要

Process for the preparation of a phenol resin modified with a liquid polybutadiene which comprises reacting a polybutadiene having a number average molecular weight of 150 to 5,000 with a phenol in the presence of an acid catalyst to obtain a composition which consists of a polybutadiene-phenol adduct and unreacted phenol, in said polybutadiene-phenol adduct, one molecule of phenol per 3 to 8 butadiene units being added to the polybutadiene, and reacting the composition of a polybutadiene-phenol adduct with a formaldehyde in the presence of a basic catalyst, said basic catalyst comprising a primary amine of the formula: R-NH2 wherein R is a hydrocarbon group having 1 to 20 carbon atoms in an amount of 0.01 to 0.5 mole per 1 mole of the phenol used for the preparation of the composition which is used alone or in combination thereof with other basic compound. Said resin composition thus prepared is useful for the preparation of a laminated sheet having excellent curing characteristics, particularly excellent electrical characteristics, punchability and flexibility.