Adhesion of ABS resin to metals treated with triazine trithiol monosodium aqueous solution

An examination was made of the adhesion of ABS resin to treated metals such as phosphor bronze, brass plates, and electronickel platings during injection molding. No adhesion to any of these metals was noted to occur under ordinary injection molding conditions, and an aqueous solution of 1,3,5-triazine-2,4,6-trithiol monosodium (TTN) was thus used to induce adhesion. Following treatment with TTN aqueous solution under optimum conditions, ABS adhered tightly to all the above metals under ordinary injection molding conditions. TTN treatment led to the formation of surface films containing metal salts of 1,3,5-triazine-2,4,6-trithiol (TT). Conditions were made optimal with regard to time, temperature. and TTN concentration. Adherent films were generally formed when bronze and brass were treated for short periods, at low temperature, and at low TTN concentration, though not so in the case of nickel plating. There was adhesion to nickel plating in the case of prolonged treatment time, high temperature, and high TTN concentration. Adherent and non-adherent films did not differ in the chemical structures of the metal salts of TT but they differed in morphology. Good adhesion was noted in the case of TT-metal salts present at low density on the metal surface. Some films reacted readily with double-bond compounds under conditions similar to those generally used for the injection molding of ABS. It was concluded that the adhesion was due to the formation of interfacial bonds during injection molding.