Abstract: The subject invention provides polyurethane foam and a method of purifying polyether polyols of non-volatile impurities for use in forming the polyurethane foam. The method includes the step of providing a crude polyether polyol having a non-volatile impurity present therein. The crude polyether polyol is contacted with an adsorbent selected from at least one of activated carbon, diatomaceous earth, charcoal, attapulgite, and clay to remove the impurity and filtered to form a purified polyether polyol. The filtering of the crude polyether polyol is carried out through a filter media that is used both in a pre-filtering step prior to adding the adsorbent and the filtering step to remove the adsorbent to reduce losses of the purified polyether polyol because of its high viscosity. The purified polyether polyol is then used to form a polyurethane foam having improved stability.

Abstract: A method for the preparation of a storage stable organic polyisocyanate having allophanate linkages prepared by reacting a urethane containing organic polyisocyanate with a reactive hydroxyl compound in the presence of a liquid organic titanium oxide, or zirconium oxide, or hafnium oxide catalyst that is fully miscible in the reactive hydroxyl compound is disclosed. After completion of the allophanate reaction, the catalyst is deactivated by the use of a strong inorganic acid, organic acid, organic chloroformate or acid chloride.