Heat resistant poly(urethane amideimide) composition and method for preparing the same

A heat resistant linear urethane-amide-imide copolymer composition for use as wire coating varnish and film material consisting essentially of the product from the process which comprises the steps of:

• (a) dissolving at least one diol compound in an inert organic solvent to form a mixture solution;
• (b) adding at least one diisocyanate compound into the mixture solution from step (a), wherein the molal quantity of said diisocyanate compound is greater than the molal quantity of said diol compound, and stirring the mixture solution resulted therefrom;
• (c) adding trimellitic anhydride into the mixture solution from step (b), wherein the molal quantity of isocyanate groups in the mixture solution is stoichiometrically equivalent to the molal sum of hydroxyl, carboxyl, and anhydride groups;
• and
• (d) stirring the mixture solution from step (c) to produce said linear urethane-amide-imide copolymer composition.