Corrosion- and chip-resistant coatings for high tensile steel
AssigneeRohm and Haas Company
InventorsTina L. Grubb, Catherine A. Kleckner, William E. Wertz, Michael C. Siminski, Andrew T. Daly, Jeno Muthiah
Life of this patent
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Abstract
Corrosion- and chip-resistant coatings for high tensile steel components, such as automotive coil springs, are formed from a coating powder composition of “toughened” epoxy resin. In a single coat embodiment, the entire coating is loaded with at least 75 phr zinc powder. In a dual coat embodiment, an inner coat is loaded with at least 75 phr zinc and an outer, zinc-free coating is reinforced by the addition of fibers and/or by a foaming agent which renders it porous.
Claims19
A method for coating a high-tensile steel surface to provide impact resistance and improved corrosion resistance, comprising the steps of:
- (1) applying a coating composition to said surface;
- wherein said coating composition comprises:
- 1) a resin, comprising:
- a) 5% to 20% by total weight of said resin of a core comprising acrylic rubber having a glass transition temperature of −30° C. or below;
- and
- b) 80% to 95% by total weight of said resin of a shell comprising an epoxy resin;
- wherein said core and said shell are chemically bonded to each other;
- and
- 2) at least 75 phr of zinc particles by total weight of said resin;
- and
- (2) heating said coating composition to fuse and cure the coating composition to form a fused and cured coating.
A method for providing a dual coating on a high-tensile steel surface for impact resistance and improved corrosion resistance, comprising:
- (1) applying a first coating composition to said surface;
- wherein said first coating composition comprises:
- 1) a resin, comprising:
- a) 5% to 20% by total weight of said resin of a core comprising acrylic rubber having a glass transition temperature of −30° C. or below;
- and
- b) 80% to 95% by total weight of said resin of a shell comprising an epoxy resin;
- wherein said core and said shell are chemically bonded to each other;
- and
- 2) at least 75 phr of zinc particles by total weight of said resin;
- (2) heating said first coating composition to fuse and cure the first coating composition to form a fused and cured first coating;
- (3) applying a second coating composition to said first coated surface;
- wherein said second coating composition comprises:
- a resin, comprising:
- 1) 5% to 20% by total weight of said resin of a core comprising acrylic rubber having a glass transition temperature of −30° C. or below;
- and
- 2) 80% to 95% by total weight of said resin of a shell comprising an epoxy resin;
- wherein said core and shell are chemically bonded to each other;
- wherein said second coating composition is zinc free;
- and
- (4) heating said second coating composition to fuse and cure the second coating composition to form a fused and cured second coating.
A method for providing a dual coating on a high-tensile steel surface for impact resistance and improved corrosion resistance, comprising:
- (1) applying a first coating composition to said surface;
- wherein said first coating composition comprises:
- 1) a resin, comprising:
- a) 5% to 20% by total weight of said resin of a core comprising acrylic rubber having a glass transition temperature of −30° C. or below;
- and
- b) 80% to 95% by total weight of said resin of a shell comprising an epoxy resin;
- wherein said core and said shell are chemically bonded to each other;
- and
- 2) at least 75 phr of zinc particles by total weight of said resin;
- (2) applying a second coating composition to said first coated surface, comprising:
- a resin, comprising:
- 1) 5% to 20% by total weight of said resin of a core comprising acrylic rubber having a glass transition temperature of −30° C. or below;
- and
- 2) 80% to 95% by total weight of said resin of a shell comprising an epoxy resin;
- wherein said core and shell are chemically bonded to each other;
- wherein said second coating composition is zinc free;
- and
- (3) heating said first and second coating compositions to fuse and cure the first and second coating compositions.
Dependencies are inferred from the claim text.