PROCESS FOR MAKING IMPROVED CORROSION PREVENTIVE ZINC CYANAMIDE

摘要

Improved corrosion preventive pigment grade zinc cyanamide suitable for protective mirror backing coatings is prepared by reacting a totally hydrated zinc oxide slurry with hydrogen cyanamide. The reaction is carried out while maintaining a stoichiometric excess of zinc oxide at an elevated temperature between about 75.degree. and about 85.degree.C. The reaction mixture is provided in a condition free of inorganic soluble salts and free of anions containing sulfur such as sulfides or sulfates.