| 摘要 |
<p>Polymer-modified polyols of reduced viscosity are made by reacting an organic polyisocyanate with a low molecular weight hydroxyl-containing compound in a polyol in the presence of a specified dispersant. The dispersant, which is of a type known for dispersing pigments in paints, is obtained by reacting (1) a copolymer comprising units derived from the following ethylenically unsaturated monomers in the stated proportions by weight based on the total weight of the copolymer: (a) 0-50% of a hydroxy group-containing monomer, and/or (b) 0-20% of an amide group-containing monomer, provided that there is always present at least 5% of (a) and (b); (c) 20-80% of a monomer free from carboxyl groups and containing a straight or brancehd chain alkyl group of from 7 to 22 carbon atoms, and (d) 0-50% of one or more monomers free from the hydroxy, amide and C7-22 alkyl groups present in (a), (b) or (c), and also, as an essential constituent, (e) up to 20% of a monomer containing an epoxide group, the total of monomers (a), (b), (c), (d) and (e) being 100%, with (2) a compound bearing a carboxyl group and a group having pigment dispersant characteristics. Preferably it is a copolymer of styrene; 2-ethyl hexyl acrylate; hydroxy isopropylmethacrylate; methacrylamide; glycidyl methacrylate in the ratios 26:40:25:5:4, modified by esterification with p-aminobenzoic acid in the presence of dimethyl dodecyl tertiary amine. The modified polyols of particular interest are those used in the manufacture of flexible foam slabstock.</p> |
