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 chip resistant and corrosion resistant coating on high tensile steel produced from a coating powder composition comprising
- (I) 100 weight parts of a resin chosen from:
- (i) a resin comprising A) an epoxy resin plus B) a polyhydroxyl functional cross-linker having a hydroxy equivalent weight of from 200 to 500, and
- (ii) a resin comprising an adduct of from 75 to 95 wt %, based on the total weight of A) plus B), of an epoxy resin A), and from 5 to 25 wt %, based on the total weight of A) plus B), of an elastomer component B) having a glass-transition temperature of−30° C. or below, and
- (II) at least 150 weight parts of zinc powder.
A chip resistant dual coating on high tensile steel comprising a first coat in contact with said high tensile steel and a second outer coat,
- said first coat produced from a coating powder composition comprising
- (I) 100 weight parts of a resin chosen from:
- (i) a resin comprising A) an epoxy resin plus B) a polyhydroxyl functional cross-linker having a hydroxy equivalent weight of from 200 to 500, and
- (ii) a resin comprising an adduct of from 75 to 95 wt %, based on the total weight of A) plus B), of an epoxy resin A), and from 5 to 25 wt %, based on total weight of A) plus B), of an elastomer B) component having a glass transition temperature of −30° C. or below, and
- (II) at least 75 weight parts of zinc powder, said second coat produced from a coating powder composition comprising
- (III) 100 weight parts of a resin chosen from:
- (i) a resin comprising A) an epoxy resin plus B) a polyhydroxyt functional cross-linker having a hydroxy equivalent weight of from 200 to 500, and
- (ii) a resin comprising an adduct of from 75 to 95 wt %, based on total weight of A) plus B), of an epoxy resin A) plus B), and from 5 to 25 wt %, based on total weight of A) plus B), of an elastomer component having a glass transition temperature of −30° C. or below, said second coating being zinc-free.
Dependencies are inferred from the claim text.