Patent ID: 6960369

Claim:
Coating solutions which suitably adhere to substrates of polyamides, polyesters and mixtures thereof, comprising: (a) a water-soluble polyamide copolymer having a solubility in water at 23 C of at least 0.5 weight percent and derived from the reaction of adipic acid and ether diamines with caprolactam and, optionally, one or more alkylene diamines, wherein the ether diamines have a molecular weight of 148 to 396 and are represented by the formulas: H2N—R1—O—R2—O—R1—NH2 wherein R1 and R2 are either —CH2—CH2— or —CH2—CH2—CH2—; and H2N—R1(—O—CH2—CH2—)XO—R1—NH2 wherein R1 is either —CH2—CH2— or —CH2—CH2—CH— and X has an average value of 2 to 6; and mixtures thereof; (b) 1 to 100 weight percent based on the weight of the water-soluble polyamide of a water-soluble crosslinking agent selected from the reaction product of formaldehyde and amine-containing compounds; and (c) 0 to 20 weight percent based on the weight of the crosslinking agent of an organic or inorganic acid having a pKa greater than 1.9.