| 摘要 |
PURPOSE:To obtain the title polyamide which gives an oriented film excellent in tensile strength, by reacting terephthalic acid containing a specified amount or less of para-toluyl acid with tolylene diisocyanate in the presence of an alkali metal compound in a solvent. CONSTITUTION:Terephthalic acid (A) which is produced, for example, by recrystallization of terephthalic acid in water and/or acetic acid at a high temperature and a high pressure, and contains para-toluyl acid in an amount of 1,000ppm or less, is reacted with tolylene-2,4-diisocyanate and/or tolylene-2,6- diisocyanate (B) using as catalyst an alkali metal compound (C) such as KF in a solvent (D) for polymerization such as anhydrous N,N'-dimethylethyleneurea at 100 deg.C or above.
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