| 摘要 |
<p>1384041 Polyisocyanurate foam UPJOHN CO 12 June 1973 [18 July 1972] 27932/73 Heading C3R A rigid foam article, having a continuous integrally formed microcellular outer layer and a cellular polymeric core and in which the major recurring unit is an isocyanurate, is prepared by bringing together in a closed mould: (I) an aromatic polyisocyanate; (II) a catalyst for trimerising I; (III) a polyol and (IV) a polyhalogenated blowing agent. As III, there is employed 0À1 to 0À5 equivalents per equivalent of I of a mixture comprising: (a) 5-60% by wt. of a polyol having a functionality of 2-8 and equivalent weight 30-200; and (b) correspondingly 95-40% by wt. of a polyether polyol selected from polyether diols having an equivalent weight 750-2100, polyether triols having equivalent weight 1500-2100, at least 50% of the OH groups present being primary OH groups. I may be polymethylene polyphenyl polyisocyanate. A typical II is N,N<SP>1</SP>,N<SP>11</SP>-tris- (dimethylaminopropyl)-s-hexahydrotriazine. In an example the polyol mixture comprises (a) a blend of (i) an adduct of propylene oxide with an aniline/formaldehyde condensate and (ii) a glycerol/propylene oxide adduct; and (b) a polyether triol adduct of propylene oxide and trimethylolpropane, capped with ethylene oxide. The foam products have good impact resistance.</p> |
