abstract |
A process is claimed for the continuous prodn. of thermoplastic polyurethane (TPU)-copolymer mixts. from: (I) 1-60 wt% thermoplastic copolymer; and (II) 99-40 wt% of the polyurethane-forming components (A) di-isocyanate, (B) linear OH-terminated polyol with a mol. wt. of 500-5000 and (C) diol or diamine chain extenders with mol. wts. of 60-500. The process comprises: (i) feeding component (I) together with part of components (A), (B) and/or (C) into an extruder through a first inlet and feeding in the rest of components (A), (B) and/or (C) at one or more later inlets; (ii) reacting (A), (B) and (C), at a mole ratio of (NCO gps. in A):(NCO-reactive gps. in B and C) = 0.9-1.2, to form the TPU; and (iii) extruding the mixt. of TPU and (I). |