| 摘要 |
<p>Prodn of cold-formable, open-cell rigid polyurethane foam (I) involves reacting (a) polyisocyanates with (b) a polyol component of cpds. with at least 2 OH gps. and mol. wt. 187-10000, chain extenders and crosslinker with OH gps, and mol wt. 32-186 deg C, water as blowing agent, tert, maine catalysts (II) and opt. silicone foam stabilisers (III). The novel features are that (a) is a mixt. (crude MDI) of 70-90 (wt.)% diphenylmethane diisocyanate, 12-30 (15-25)% of which is 2,4'-isomer, and 10-30% polyphenyl-polymethylene polyisocyanates and (b) is a mixt. of 50-70% di- and/or trifunctional polyether polyols with OH number 28-600, 20-35% phthalate polyester diola with OH mnumber 150-440, 2-10% glycerol, 3.5-7% water, 0.3-1% (II), which can be included in (I) and opt 0.1-2% (III).</p> |
