PREPARATION OF POLYIMIDE DRAWN MOLDING HAVING EXCELLENT PHYSICAL PROPERTY

摘要

PURPOSE:To mold a drawn polyimide molding easily and with good re productivity of heat resistance and so on, by swelling an aromatic polyamic acid having high heat resistance in a specified solvent, drawing it thereafter and heat-treating it finally. CONSTITUTION:A molding of an aromatic polyamic acid (containing 50wt% or less of an organic polar solvent) obtained by polymerizing an aromatic tetracarboxylic acid component and an aromatic diamine component in an organic polar solvent is sufficiently swollen in a solvent for swelling which is compatible with the organic polar solvent and at the same time does not dissolve the aromatic polyamic acid (i.e., a mixed solvent of water, alcohol and so on with an organic polar solvent such as dimethyl sulfoxide and so on). The swollen undrawn molding is drawn by 1.1-3.0 times at a drawing temp. of 0-200 deg.C in a sweeling solvent. After removing the solvent, the polyamic acid is imidified by heat treatment. A polyimide drawn molding having good heat resistance and excellent physical properties can be thereby prepared.