| 摘要 |
<p>1290220 Polyurethane prepolymers NAPHTACHIMIE 24 July 1970 [25 July 1969] 36046/70 Addition to 1212483 Heading C3R Polyurethane prepolymers containing terminal isocyanate groups are prepared by reacting 100 to 5000 p.p.m. by weight of a halide of silicon and/or boron with a polyhydroxylated compound containing less than 2000 p.p.m. by weight of water and reacting the r esulting product at 50 to 100‹C. with an organic polyisocyanate. The polyhydroxylated compound is suitably first dehydrated physically to contain less than 500 p.p.m. of residual water. Preferred halides are silicon tetrachloride and boron trichloride. Hydroxylated compounds and polyisocyanates conventionally used in the polyurethane art are used. The prepolymers may be used in the manufacture of paints, coatings, elastomers, mastics and varnishes.</p> |
