Phenol formaldehyde resins

Abstract From the Canadian patent

A process for forming a phenol formaldehyde resin the process comprising the , steps of: (i) reacting phenol with an excess of a formaldehyde material in the presence of an acid or base catalyst until water separates from the reactants as an immiscible layer; (ii) adding a mixture comprising an excess of a polyhydric alcohol and an aromatic dicarboxylic or tricarboxylic acid salt or , anhydride thereof to the phenol and formaldehyde reaction mixture followed by addition of an alpha hydroxy acid; (iii) adding a non-aqueous solvent wherein , at last some of said water is removed either before addition of the mixture preparated in step (ii) or after addition of the alpha hydroxy acid; …