| 摘要 |
1,235,000. Thickening latices. BALM PAINTS Ltd. 30 Dec., 1968 [28 Dec., 1967], No. 61665/68. Heading C3P. Aqueous polymer latices having a flow coefficient, greater than 1À5 and a plastic viscosity of at least 0À3 poise at 25‹ C. and. polymer particles of 0À04-2 microns are thickened by adding 0À1-10% by weight of dispersed polymer of a copolymer of vinyl alcohol and a C 4 - C 18 . comonomer (which forms a water-insoluble homopolymer) having a molecular weight of 2000-10,000 and in which the molar percentage of comonomer varies between 10 and 50% for a C 4 monomer and 0À2 and 8% for a C 13 -C 18 monomer as given in a table. In the examples acrylic copolymer latices are thickened with (a) partially hydrolysed polyvinyl acetate, (b) a partial acetal of polyvinyl alcohol with benzaldehyde or propionaldehyde, (c) hydrolysed vinyl acetate-vinyl tert.-carboxylate, (d) hydrolysed polyvinyl acetate chain-stopped, with n-octyl mercaptan. |
