PURPOSE: A molding material composition capable of forming highly heat-resistance moldings, comprising poly-p-vinylphenol or a brominated poly-p-vinylphenol, hexamethylenetetramine and a specified catalyst.

CONSTITUTION: At least one compound, as a reaction catalyst, selected from the group consisting of calcium hydroxide, magnesium oxide and magnesium hydroxide is added to a mixture containing poly-p-vinylphenol and/or brominated poly-p-vinylphenol and hexamethylenetetramine. Preferably, the amount of the reaction catalyst is selected so that it accounts for 1W5wt% of the entire molding material. When the amount is below 1wt%, the effect of improving the reaction rate becomes low, whereas if it exceeds 5wt% it is difficult to use the mixture as a molding material. As the poly-p-vinylphenol and the brominated poly-p-vinylphenol, those having a number-average MW of 1,000W3,000 are preferably used.