Sealer-primer for elastomeric coatings

Claim 1

A sealing-primer composition comprising: A. a hydroxyl-containing, carboxyl-containing reaction product of: 1. an ungelled, hydroxy-containing urethane reaction product of an organic polyisocyanate and a polyhydric material, said reaction being terminated when the intrinsic viscosity of the reaction product is 1.0 deciliter per gram or less and the NCO/OH equivalent ratio being less than 1, with the major portion of said polyhydric material being selected from the group consisting of polyether polyols, saturated polyester polyols and mixtures thereof, wherein said polyhydric material contains no more than about 1 gram-mole of compounds having a functionality of 3 or more per 500 grams of polyhydric material, said urethane reaction product having a hydroxyl value of between about 10 and about 200; and 2. 0.1 to about 10 percent by weight based on total weight of the reaction mixture of a compound selected from the group consisting of polycarboxylic acids and polycarboxylic acid anhydrides; the acid and anhydride groups reacting with the hydroxyl groups of the urethane product to form a hydroxyl-containing, carboxyl-containing reaction product, and B. an amine-aldehyde condensation product.

Claim 10

A method of producing a sealing-primer composition comprising: A. reacting an organic polyisocyanate with a polyhydric material, said reaction being terminated when the intrinsic viscosity of the reaction product is 1.0 deciliter per gram or less, the NCO/OH equivalent ratio being less than 1, the major portion of said polyhydric material being selected from the group consisting of polyether polyols, saturated polyester polyols, and mixtures thereof, wherein said polyhydric material contains no more than about 1 gram-mole of compounds having a functionality of 3 or more per 500 grams of polyhydric material, the reaction product thereof being an ungelled, hydroxyl-containing urethane reaction product having a hydroxyl value between about 10 and about 200; B. reacting said ungelled, hydroxyl-containing urethane reaction product with 0.1 to about 10 percent by weight based on total weight of the reaction mixture of a compound selected from the group consisting of polycarboxylic acids and polycarboxylic acid anhydrides, the acid and the anhydride groups reacting with the hydroxyl groups of the urethane reaction product, thereby producing a modified urethane reaction product containing hydroxyl groups and carboxyl groups; and C. adding an amine-aldehyde condensation product to said modified urethane reaction product.

Claim 11

A method of producing a sealing-primer composition comprising: A. reacting an organic polyisocyanate with a polyhydric material, said reaction being terminated when the intrinsic viscosity of the reaction product is 1.0 deciliter per gram or less, the NCO/OH equivalent ratio being less than 1, the major portion of said polyhydric material being selected from the group consisting of polyether polyols, saturated polyester polyols, and mixtures thereof, wherein said polyhydric material contains no more than about 1 gram-mole of compounds having a functionality of 3 or more per 500 grams of polyhydric material, the reaction product thereof being an ungelled, hydroxyl-containing urethane reaction product having a hydroxyl value between about 10 and about 200; B. reacting said ungelled, hydroxyl-containing urethane reaction product with 0.1 to about 10 percent by weight based on total weight of the reaction mixture of a compound selected from the group consisting of polycarboxylic acids and polycarboxylic acid anhydrides, the acid and the anhydride groups reacting with the hydroxyl groups of the urethane reaction product, thereby producing a modified urethane reaction product containing hydroxyl groups and carboxyl groups; and C. adding an amine-aldehyde condensation product to said modified urethane reaction product.