| 摘要 |
<p>In forming a flexible, highly resilient polyurethane foam, the improvement comprises incorporating into the reaction mixt., a foam stabilising supplemental polyether polyol (I) contg. >=30% of primary OH gps., an av. of 2-6 OH gps., OH no. of 250-800. (I) is an adduct of a 2-4C alkylene oxide and a mixt. of (i) dextrose and water, (ii) dextrose and an aliphatic diol or triol or (iii) dextrose, water and an aliphatic diol or triol. The reaction mixture contains an org. polyisocyanate, foaming agent, catalyst, polydimethylsiloxane liquid surfactant and a polyether polyol (II) of mol. wt. >=4000 and having a polyhydroxy alcohol nucleus of functionality 2-4 to which are attached polyoxyalkylene segments and a ratio of primary to secondary OH gps. of 1.5-6:1. The foams do not substantially shrink or collapse before they are fully cured. They have a density of 1.8-3.8, pref. 2.2-3.0 lbs/cu. ft. and an SAC factor, as a measure of support provided by cushioning material, of 2.4-2.7; the foams are quite flexible and soft at the surface, exhibit little or no tendency to bottom out. The foams also have good tear strength, tensile strength and elongation and are used in moulded automobile seats and other cushioning applications.</p> |
