Abstract
Polyimide resin of solvent-soluble type, which is called “X-resin” in short, was discovered lately. It is soluble in
dimethylacetoamid (DMAc), and new extensive applications are expected.Some physical, chemical and electrical characteristics are studied from the viewpoint of polymer material for hybrid
application. Particularly comparison of the characteristics of X-resin specimens before and after long term exposure
to humid and hot environments were made, remembering that electronic devices often operate under such conditions
in Japan.From the results obtained up to now, no conspicuous difference seems to exist between the characteristics of X-resin
and those of the conventional (i.e., solvent-insoluble) resins, as published in various literature. It should be noted,
however, that some unusual effects, i.e., the remarkable increase in surface resistivity σ, the evident decrease in tan