Abstract: A heat resistant resin composition comprising a polyamide imide resin having carboxyl groups and modified with an N-methylolated methacryl- or acryl-amide compound and, when desired, further with a bismaleimide compound. The composition has improved properties over conventional polyamide imide resins. When the composition is used, for example, in the form of a film for printed circuit boards, the film has improved heat resistance and enhanced flexural strength and is capable of withstanding soldering baths at high temperatures.

Abstract: A composition comprising a varnish of heat-resistant resin having active hydrogen in the molecule and a bismaleimide compound or derivative thereof admixed with the varnish affords a heat-resistant resin product of improved properties. Especially when a bismaleimide compound or derivative thereof is added to a varnish of polyimide resin having active hydrogen in the molecule and the composition is applied to a metal film substrate to form a resin film, the film has improved peel strength and, in itself, also has improved strength and elongation.