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US 5,176,894 AGranted
Process for making improved corrosion preventive zinc cyanamide
AssigneeWayne Pigment Corp.
InventorJohn Sinko
Life of this patent
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Abstract
Improved corrosion preventive pigment grade zinc cyanamide suitable for protective mirror backing coating 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. C. 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.
Claims4
A process for producing pigment grade zinc cyanamide having enhanced corrosion preventive activity comprising
- providing an aqueous mixture of finely divided zinc oxide substantially free of soluble inorganic salts and substantially free of materials having sulfur containing anions,
- totally hydrating said mixture by high speed stirring at approximately 75.degree. to 85.degree. C.
- mixing with said resultant slurry a stabilized soluble aqueous solution of hydrogen cyanamide free of soluble inorganic salts and free of material having sulfur containing anions, and reacting said materials at a temperature between about 75.degree. and 85.degree. C.
Dependencies are inferred from the claim text.