| 摘要 |
<p>Urethane elastomer of density is not 1 g./cc. is prepd. from (a) a (ester modified) polyether polyol having 3-4 OH gps. per molecule and a mol. wt. is not 2,000, (b) a liq. accelerator-extender such as glycerine, (di)ethylene glycol, dipropylene glycol or the reaction prodt. of glycerine or pentaerythritol with an alkylene oxide or epihalohydrin in a ratio to provide 1-2 moles of alkylene oxide or epihalohydrin per OH of glycerine or pentaerythritol, (c) a liquid isocyanate terminated prepolymer prped. from a stoichiometric excess of a polyisocyanate with a polyhydroxy cpd. having 2-3 OH gps. and a mol. wt. 62-600, the prepolymer having NCO content 10-50wt. %, and (d) an organometallic catalyst where components (a) and (b) are present in quantities which provide a OH equiv. ratio of (b):(a) of is not 1:1 and 20: 1, the (c) provides NCO equiv. to OH equiv. present in (c) and (b) of 0.75:1-1.5:1 and (d) is used in at is not 0.3wt.% on sum of all four components. The compsn. provides fast-setting polyurethane cast elastomers.</p> |
