Reference

Corrosion-resistant adherent coatings on aluminum surfaces and aqueous acid solutions for chemical conversion coatings

Corrosion-resistant adherent coatings on aluminum surfaces and aqueous acid solutions for chemical conversion coatings. Kelly, Timm L. (Amchem Products, Inc., USA). Ger. Offen. DE 2715292 13 Oct 1977, 40 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: C23F007-00. PRIORITY: US 76-674015 5 Apr 1976. DOCUMENT TYPE: Patent CA Section: 56 (Nonferrous Metals and Alloys) Section cross-reference(s): 17 Al cans are coated with corrosion-resistant, colorless, adherent, and nontoxic films by spraying a soln. of pH 1.5-4.0 contg. Zr and/or Ti 10-125, phosphate 10-1000, and fluoride 10-500 ppm; the amt. of fluoride being sufficient to form a sol. complex with Zr and Ti. The soln. does not contain Cr(VI) or other poisonous components and the film does not become dark when held in hot water. The film can be used as a primer for siccative coatings. Thus, a soln. contg. (NH4)2ZrF6 [16919-31-6] 0.240, HBF4 0.264, and H3PO4 0.294 g/L was sprayed for 25 s at 43° on degreased Al cans. The sprayed cans were water-rinsed and dried at 204° for 2 min. No blackening occurred while holding the cans in boiling water.

Conversion coatings for food and beverage cans

Conversion coatings for food and beverage cans. (Nippon Paint Co., Ltd., Japan). Jpn. Kokai Tokkyo Koho JP 59083775 A2 15 May 1984 Showa, 5 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: C23F007-08. APPLICATION: JP 82-192741 2 Nov 1982. DOCUMENT TYPE: Patent CA Section: 55 (Ferrous Metals and Alloys) Acidic aq. solns. contg. hexafluorozirconate with Zr(IV), phytic acid or its salt, H3PO4 or its salt, and chlorate are used in the conversion treatment. The method does not cause serious environmental pollution, forms nonpoisonous chem. conversion coatings having excellent corrosion resistance and adhesion to metal surfaces, and is useful for manufg. cans for food and beverages. Thus, SPCC steel [39462-15-2] sheet was treated by spraying with an aq. acidic soln. at pH 3.5 contg. (NH4)2ZrF6 [16919-31-6], phytic acid [83-86-3], H3PO4, and NaClO3, washed with water, dried to form a coating, and coated with epoxy paint.