| 摘要 |
PURPOSE:To stably obtain the titled material having good impact resistance in the lateral direction thereof, free from thickness irregularity and having good flatness, by a method wherein a polyamide-imide resin comprising specific main structural units is melt extruded from the slit gap of a die lip while adding an alkali metal hydroxide to said resin prior to extrusion. CONSTITUTION:A polyamide-imide resin having repeating units each represented by the formula (wherein Ar is a trivalent aromatic group including a 6-membered carbocyclic ring, R is a divalent aromatic group and/or an aliphatic residue, R' is H, methyl or phenyl) as the main structural units thereof is melt extruded from the slit gap of a die lip. In this case, said resin is extruded from the gap of the die lip while a compound such as an alkali (alkaline earth) metal hydroxide or a salt of a weak acid (e.g., lithium carbonate) is added to said molten resin prior to the extrusion in an amount of 0.008-0.2wt% to obtain the objective sheet material. |
