Sealerless primers

Claim 1

An article comprising a metal substrate having adhered thereto a hard, crack-resistant coating, said coating comprising a layer of cured primer composition adhering to said metal substrate and a layer of an acrylic polymer superimposed upon and adhering to said cured primer composition, wherein said cured primer composition is a mixture of a. a saturated resin which is a saturated polyester having hydroxyl functionality, a saturated polyether having hydroxyl functionality or a saturated polyurethane having hydroxyl functionality, and which has been cured with an aminoplast curing agent produced from the condensation products of amines or amides with an aldehyde, to form a thermoset polymer, and b. a thermoplastic acrylic polymer which (1) is selected from the group consisting of addition polymers of esters of alpha-beta ethylenically unsaturated acids and interpolymers of esters of alpha-beta ethylenically unsaturated acids with other ethylenically unsaturated compounds, (2) is essentially uncured with said aminoplast curing agent, and (3) is soluble in solvents in which it was soluble before said primer composition was cured.

Claim 8

A method of coating a metallic substrate comprising: a. coating said metallic substrate with a primer composition containing: (1) an aminoplast curing agent produced from the condensation products of amines or amides with an aldehyde, (2) a saturated resin which is curable with said aminoplast curing agent to form a thermoset polymer and which is a saturated polyester having hydroxyl functionality, a saturated polyether having hydroxyl functionality or a saturated polyurethane having hydroxyl functionality, and (3) a thermoplastic acrylic polymer which (a) is selected from the group consisting of addition polymers of esters of alpha-beta ethylenically unsaturated acids and interpolymers of esters of alpha-beta ethylenically unsaturated acids with other ethylenically unsaturated compounds, (b) is essentially non-curable with said aminoplast curing agent; b. curing said primer composition to form a mixture of (1) a thermoset polymer of said saturated resin and said aminoplast curing agent, and (2) said thermoplastic acrylic polymer which is soluble in solvents in which it was soluble before said curing; c. coating said cured primer composition with a non-aqueous dispersion of an acrylic polymer; and d. drying said non-aqueous dispersion to provide a coating of said acrylic polymer contained therein.

Claim 9

A method of coating a metallic substrate comprising: a. coating said metallic substrate with a primer composition containing: (1) an aminoplast curing agent produced from the condensation products of amines or amides with an aldehyde, (2) a saturated resin which is curable with said aminoplast curing agent to form a thermoset polymer and which is a saturated polyester having hydroxyl functionality, a saturated polyether having hydroxyl functionality or a saturated polyurethane having hydroxyl functionality, and (3) a thermoplastic acrylic polymer which (a) is selected from the group consisting of addition polymers of esters of alpha-beta ethylenically unsaturated acids and interpolymers of esters of alpha-beta ethylenically unsaturated acids with other ethylenically unsaturated compounds, (b) is essentially non-curable with said aminoplast curing agent; b. curing said primer composition to form a mixture of (1) a thermoset polymer of said saturated resin and said aminoplast curing agent, and (2) said thermoplastic acrylic polymer which is soluble in solvents in which it was soluble before said curing; c. coating said cured primer composition with a non-aqueous dispersion of an acrylic polymer; and d. drying said non-aqueous dispersion to provide a coating of said acrylic polymer contained therein.