GB655689A - Acetone-formaldehyde-phenol resins - Google Patents

Abstract

Heat hardenable resins are made by condensing acetone and formaldehyde under basic conditions and reacting the resulting product under basic conditions with a phenol in amount sufficient to react with unreacted formaldehyde and methylol groups in the product. Novolak type condensation products of monohydric phenols and aldehydes may replace phenols, those preferred being made from phenol and acetaldehyde or butyraldehyde. In examples: (1) the reaction product of formaldehyde (2 mols.) with acetone (1 mol.) in the presence of caustic soda, is reacted with phenol in the presence of ammonia and the resulting product is dehydrated by distillation at atmospheric pressure and finally under vacuum; (2) the product of acetone (25 mols.) with formaldehyde (65 mols.) in the presence of diethylamine, is reacted with phenol in the presence of ammonia and dehydrated; (3) the dehydrated product of equimolecular proportions of acetone with formaldehyde in the presence of caustic soda is heated with a novolak resin obtained by reacting a mixture of m- and p-cresols with formaldehyde under acid conditions, and dehydrated to give a product which is heat reactive when mixed with hexamethylenetetramine; (4) the product of acetone (1 mol.) and formaldehyde (2 mols.) in the presence of caustic soda, is reacted under basic conditions with a phenol-acetaldehyde resin made from equimolecular proportions of phenol and acetaldehyde under acid conditions, and dehydrated. Specification 515,467 is referred to.