MICROCELLULAR POLYURETHANE ELASTOMER CONTAINING UREA GROUPS

摘要

Microcellular polyurethane elastomer (I) containing urea groups, with improved dynamic mechanical properties, is based on an isocyanate consisting mainly of 4,4'-diphenylmethane diisocyanate (MDI). In addition to the main low molecular main signal in gel permeation chromatography (GPC) of a solution prepared from (I) in N,N-dimethylformamide (DMF) with 1% di-n-butylamine at 90 deg C, the signal has peak(s) at an apparent molecular weight > 250000 g/mole (polymethyl methacrylate standard), which are reduced or vanish when lithium chloride (LiCl) is added to the solution. Preferably (I) has a urea content of 14-18 wt.%.