Polyamide hot-melt adhesives prodn., esp. from polyamide re-granulate

摘要

Prodn. of polyamide hot-melt adhesives (I) with narrow, definite mol.wt. and m.pt. ranges comprises decompsn. of polyamide granules, pref. polyamide regranulate (II) from a homogeneous fusible polyamide or pref. a mixt. of different amts. of at least 2 such polyamides, with an aliphatic dicarboxylic acid (III), pref. with a mixt. of at least 2 such diacids in the amt. calculated as below, for 30-45 mins. at 180-300 (pref. 240-275) deg.C in the melt under inert gas at normal pressure with stirring, to give a reactive, low-mol. wt., difunctional COOH-terminated prepolymer mixt. (IV), followed by co-condensation of (IV) with aliphatic diamine(s) (V) for 30-60 mins. at 220-300 (pref. 240-275) deg.C in the melt under inert gas at normal pressure with stirring, to give a PA co-condensate (I) with mol. wt. 5000-15,000.