CPC C23C 22/66 (2013.01) [B05D 3/102 (2013.01); B41N 1/083 (2013.01); C09D 5/08 (2013.01); C09D 5/12 (2013.01); C23C 22/56 (2013.01); C23C 22/73 (2013.01); C23C 22/76 (2013.01); C23C 22/78 (2013.01); C23F 1/20 (2013.01); C23F 11/167 (2013.01)] | 19 Claims |
1. A continuous coil pretreatment process comprising:
a) cleaning a surface of an aluminum sheet or a coil; then
b) etching the surface of the aluminum sheet or the coil by spraying the surface of the aluminum sheet or the coil with an acidic etching solution comprising up to about 8 vol. % of sulfuric acid for a period of from about 5 seconds to about 15 seconds, wherein the acidic etching solution in contact with the surface of the aluminum sheet or the coil is controlled by replacing or replenishing the acidic etching solution when a combined concentration of aluminum and magnesium ions exceeds 1,000 ppm; then
c) rinsing the surface of the aluminum sheet or the coil with deionized water; then
d) applying to the surface of the aluminum sheet or the coil a solution comprising a vinylphosphonic acid-acrylic acid (VPA-AA) copolymer; then
e) rinsing the surface of the aluminum sheet or the coil by (i) spraying the surface of the aluminum sheet or the coil with deionized water in a spray direction opposite a feed direction of the aluminum sheet or the coil as it advances in the continuous coil pretreatment process, (ii) providing a water dam at an entry point of an exit squeegee roll, and (iii) continuously rinsing a surface of the exit squeegee roll; and then
f) drying the surface of the aluminum sheet or the coil.
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