GB1001946A - Improvements in or relating to the manufacture of polyols - Google Patents

Abstract

Rigid, flexible, cellular or homogeneous polyurethanes may be made by reacting an organic polyisocyanate with a hydroxyl group-containing oxyalkylated aromatic amine made by reacting an aromatic amino compound containing at least two primary or secondary amino groups, at least one of which is directly attached to an aromatic nucleus, with from 0.1 to 0.6 molecular proportions of alkylene oxide for each equivalent proportion of active hydrogen in the amino compound, incorporating an alkaline catalyst which is then reacted with the hydroxyl groups with elimination of water and subsequently continuing the addition of alkylene oxide. The polyisocyanates include aliphatic diisocyanates, aromatic diisocyanates, cycloaliphatic dissocyanates, triisocyanates and reaction products of a diisocyanate with polyhydric alcohols. Foamed polyurethanes may be made by carrying out the reaction in the presence of water and/or a low boiling point liquid such as a fluorinated alkaline. Suitable catalysts include tertiary amines, organotin compounds, potassium acetate, iron acetylacetonate, stannous carboxylates and lead carboxylates. Surface-active agents may be present including alkyl and aryl polysiloxanes, siloxane-oxyalkylene block copolymers, oxyethylated phenols, oxyethylated fatty alcohols and block copolymers of ethylene and propylene oxides.ALSO:Hydroxyl group-containing oxyalkylated aromatic amines are made by reacting an aromatic amino compound containing at least two primary or secondary amino groups, at least one of which is directly attached to an aromatic nucleus, with from 0-1 to 0-6 molecular proportions of alkylene oxide for each equivalent proportion of active hydrogen in the amino compound, incorporating the alkaline catalyst which is then reacted with the hydroxyl groups of the partially oxyalkylated amino compound with elimination of water and subsequently continuing the addition of alkylene oxide until an oxyalkylated aromatic amine having the desired molecular weight is obtained. Suitable amino compounds are listed, 2: 4- and 2: 6-diaminotoluenes and mixtures thereof being preferred. Alkylene oxides include ethylene oxide, 1: 2-propylene oxide, 1: 2-butylene oxide, 2: 3-butylene oxide and mixtures thereof. Temperatures of from 50 DEG to 150 DEG C. and pressures of up to 80 p.s.i. may be employed in reacting the amine and alkylene oxide. Alkaline catalysts include alkali metal hydroxides and alcoholates and quaternary ammonium hydroxides. The alkylene oxide reacted in the final stage may be the same or different from that used prior to incorporation of catalyst. The oxyalkylation products may be rendered alkali-free by treatment with acid followed by filtration or treatment with active carbon or an absorbent earth followed by filtration. A detailed example is given.