Coating composition for metal substrates
AssigneeThe Dexter Corporation
InventorLawrence P. Seibel
Life of this patent
Estimating the term…
Abstract
A coating composition for application to primed metal substrates as a topcoat is disclosed. The coating composition is especially useful on metal closures for vacuum-packed food products. The coating composition is free of a halide-containing vinyl polymer and comprises: (a) an epoxy novolac resin, (b) a phenolic resin, (c) a polyester, and (d) an elastomer, in (e) a nonaqueous carrier.
Claims25
A coating composition for application to a primed metal substrate comprising:
- (a) about 13% to about 30%, by weight of nonvolatile material, of an epoxy novolac resin having an epoxy functionality of about 2 to about 6 and an epoxy equivalent weight of about 100 to about 210;
- (b) about 40% to about 60%, by weight of nonvolatile material, of a phenolic resin;
- (c) about 15% to about 30%, by weight of nonvolatile material, of a polyester having a weight average molecular weight of about 1,000 to about 50,000;
- (d) about 5% to about 20%, by weight of nonvolatile material, of an elastomer;
- and
- (e) a nonaqueous carrier;
- wherein the composition has a ratio of epoxy novolac resin to phenolic resin of about 25:75 to about 33:66 and a ratio of elastomer to polyester of about 1:1 to about 1:2;
- and
- wherein the composition is free of a halide-containing vinyl polymer.
A method of coating a metal substrate comprising:
- (a) applying a primer coating composition to at least one surface of the metal substrate;
- (b) heating the metal substrate having the primer coating composition applied thereon for a sufficient time and at a sufficient temperature to cure the primer coating composition and provide a primed metal substrate;
- (c) applying a coating composition to the primed metal substrate, said coating composition comprising:
- (i) about 13% to about 30%, by weight of nonvolatile material, of an epoxy novolac resin having an epoxy functionality of about 2 to about 6 and an epoxy equivalent weight of about 100 to about 210,
- (ii) about 40% to about 60%, by weight of nonvolatile material, of a phenolic resin,
- (iii) about 15% to about 30%, by weight of nonvolatile material, of a polyester having a weight average molecular weight of about 1,000 to about 50,000,
- (iv) about 5% to about 20%, by weight of nonvolatile material, of an elastomer, and
- (v) a nonaqueous carrier,
- wherein the composition has a ratio of epoxy novolac resin to phenolic resin of about 25:75 to about 33:66 and a ratio of elastomer to polyester is about 1:1 to about 1:2, and
- wherein the composition is free of a halide-containing vinyl polymer;
- and
- (d) heating the primed metal substrate having the coating composition applied thereon for a sufficient time and at a sufficient temperature to remove the nonaqueous carrier from the composition and provide a crosslinked cured coating composition.
A metal article having at least one surface thereof coated with a primer and an adherent layer of a cured coating composition, said cured coating composition resulting from curing a coating composition comprising:
- (a) about 13% to about 30%, by weight of nonvolatile material, of an epoxy novolac resin having an epoxy functionality of about 2 to about 6 and an epoxy equivalent weight of about 100 to about 210,
- (b) about 40% to about 60%, by weight of nonvolatile material, of a phenolic resin,
- (c) about 15% to about 30%, by weight of nonvolatile material, of a polyester having a weight average molecular weight of about 1,000 to about 50,000,
- (d) about 5% to about 20%, by weight of nonvolatile material, of an elastomer, and
- (e) a nonaqueous carrier,
- wherein the composition has a ratio of epoxy novolac resin to phenolic resin of about 25:75 to about 33:66 and a ratio of elastomer to polyester of about 1:1 to about 1:2;
- and
- wherein the composition is free of a halide-containing vinyl polymer.
Dependencies are inferred from the claim text.