| 摘要 |
<p>Filled polyurethane foams are prepd. by reacting (a) a polyol contg. the uniformly finely distributed filler, with (b) an isocyanate and additives. The filler is mixed into the polyol under high shear stress, by means of a stirrer plate carrying knife blades protruding from the plate; the angle of the blades to the plate radius has a statistical distribution between 0 degree and 180 degrees. The peripheral speed of the mixer is pref. 20-65 m/second, and the plate rotates at 1500-3000 revs./minute. The grain size of the filler is reduced to 10-30 my. The filler, e.g. heavy spar, is mixed into the polyol already contg. the activator and blowing agent. The foams have better cross-linking and better mechanical properties, and give improved sound damping. Larger amts. of filler can be worked into the foam.</p> |
