Liquid sorbent

A process for preparing a polyurethane particulate liquid absorbent which comprises:

• (i) reacting together at a temperature of from 180.degree. C. to 200.degree. C., for a tame of less titan 10 minutes, a prepolymer of the formula A ##STR4## with a prepolymer of the general formula B ##STR5## in the presence of a lower alkylester solvent of the general formula C
• R.sub.1 COOR.sub.4 C
• in which:
• n represents 1, 2, or 3;
• R.sub.1 represents a lower alkyl group having 1 to 6 carbon atoms;
• R.sub.2 represents hydrogen, or a lower alkyl group having 1 to 4 carbon atoms;
• and;
• each of R.sub.3 and R.sub.4 represents a lower alkyl group having 1 to 3 carbon atoms, and when R.sub.2 is other than hydrogen, It is in the meta- or para-position relative to the -NH- linkage;
• and wherein the weight ratio of prepolymer of formula A to prepolymer of formula B is about 3:1, and the reaction mixture contains from 22% to 25% by weight of ester solvent;
• (ii) cooling the titus formed polymer;
• (iii) adding thereto an alcoholic medium chosen from the group consisting of
• (a) ethanol;
• or
• (b) a mixture of ethanol, methanol and water containing 85% by weight ethanol, up to 15% by weight methanol, remainder water;
• or
• (c) ethanol containing from 4% by weight to 6% by weight isopropanol;
• (iv) adding thereto with mixing hexamethylene tetramine,
• (v) allowing the spontaneous reaction to proceed thereafter during which a temperature in the range of 55.degree. C. to 65.degree. C. is developed, and during which at least some of both tile lower alkyl ester solvent, the alcoholic medium, and any water present, to evaporate;
• and
• (vi) recovering a particulate polyurethane product.