Polymer alloy coating for metal substrate

A polymer alloy coating consisting essentially of a polyphenylene sulfide and an amount of a polyimide sufficient to enhance the adhesivness of the polyphenylene sulfide to a metal substrate without substantially changing the melt flow properties, chemical resistance and thermal stability of the polyphenylene sulfide, wherein the polyimide is produced by the crosslinking and curing of a polyimide oligomer of the formula:

• ##STR5## wherein n is from about 1 to about 2.

A polymer alloy resin composition consisting essentially of a polyphenylene sulfide resin and an acetylene terminated aromatic polyimide oligomer resin, the amount of polyimide resin, when crosslinked and cured, being sufficient to enhance the adhesiveness of the polyphenylene sulfide to a metal substrate without substantially changing the melt flow properties chemical resistance and thermal stability of the polyphenylene sulfide.

A polymer alloy resin composition consisting essentially of a polyphenylene sulfide resin and a polyimide oligomer resin, the amount of polyimide resin, when crosslinked and cured, being sufficient to enhance the adhesivness of the polyphenylene sulfide to a metal substrate without substantially changing the melt flow properties, chemical resistance and thermal stability of the polyphenylene sulfide, wherein the polyimide oligomer resin is of the formula:

• ##STR7## wherein n is from about 1 to about 2.

A method of enhancing the adhesiveness of a polyphenylene sulfide resin to a metal substrate without substantially changing the melt flow properties, chemical resistance and thermal stability of the polyphenylene sulfide comprising adding to the resin an effective amount to achieve such enhancement of an acetylene terminated aromatic polyimide oligomer resin.

A method of enhancing the adhesiveness of a polyphenylene sulfide resin to a metal substrate without substantially changing the melt flow properties, chemical resistance and thermal stability of the polyphenylene sulfide comprising adding to the resin an effective amount to achieve such enhancement, of a polyimide oligomer resin having the formula:

• ##STR10## wherein n is from about 1 to about 2.

A process for coating a metal substrate comprising:

• (a) applying to the substrate a coating of a polyimide produced by the crosslinking and curing of an acetylene terminated aromatic polyimide oligomer to produce a polyimide primed substrate;
• and
• (b) applying to the primed substrate a coating of polyphenylene sulfide.