Continuous coil pretreatment process
AssigneeArconic Technologies LLC
InventorsMichael Bull, Theresa Elizabeth MacFarlane
Life of this patent
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Abstract
Described herein is a continuous coil pretreatment process used to treat the surface of an aluminum alloy sheet or coil for subsequent deposition of an acidic organophosphorus compound. The process can include applying a cleaner to a surface of an aluminum sheet or a coil; etching the surface of the aluminum sheet or the coil with an acidic solution; rinsing the surface of the aluminum sheet or the coil with deionized water; applying to the surface of the aluminum sheet or the coil a solution of an acidic organophosphorus compound; rinsing the surface of the aluminum sheet or the coil with deionized water; and drying the surface of the aluminum sheet or the coil.
Claims11
A continuous coil pretreatment process comprising:
- (a) uncoiling a coil of an aluminum alloy sheet for use in the continuous coil pretreatment process, wherein the aluminum alloy sheet is one of a 5xxx aluminum alloy and a 6xxx aluminum alloy, wherein, as uncoiled, the aluminum alloy sheet comprises an undesired oxide layer, wherein the undesired oxide layer comprises at least one of entrapped oils, loosely adhering oxides, and debris;
- then;
- (b) applying a cleaner to a surface of the aluminum alloy sheet;
- then
- (c) etching the surface of the aluminum alloy sheet for up to 15 seconds, wherein the etching comprises:
- applying an etchant to the surface of the aluminum alloy sheet, wherein the etchant comprises 1 vol. % to 15 vol. of an acid, 0.05 vol. % to 4 vol. % of an accelerator, and 0.1 vol. % to 10 vol. % of a surfactant;
- wherein, at least partially due to the applying step (b) and the etching step (c), the undesired oxide layer is removed from the aluminum alloy sheet;
- then
- (d) rinsing the surface of the aluminum alloy sheet with water;
- wherein the rinsing comprises at least one rinsing step, wherein the water used in a final rinsing step has a conductivity of not greater than 25 μS/cm;
- wherein, after the rinsing step (d), and at least in part due to the applying step (b) and the etching step (c), the aluminum alloy sheet realizes a water break free surface;
- then
- (e) applying a pretreatment solution to the water break free surface of the aluminum alloy sheet, wherein the applying step occurs for up to 20 seconds;
- wherein the pretreatment solution comprises from 0.1 wt. % to 10 wt. % of a vinylphosphonic acid-acrylic acid copolymer;
- and
- wherein the applying step comprises forming a monolayer on the aluminum alloy sheet from the vinylphosphonic acid-acrylic acid copolymer;
- then
- (f) rinsing the aluminum alloy sheet having the monolayer thereon with a solvent, wherein the rinsing comprises removing at least some unattached vinylphosphonic acid-acrylic acid copolymer from the aluminum alloy sheet;
- then
- (g) drying the surface of the aluminum alloy sheet;
- and then
- (h) recoiling of the aluminum alloy sheet having the monolayer thereon.
Dependencies are inferred from the claim text.