| 摘要 |
PURPOSE:To obtain the titled powder with little impurities, outstanding in water resistance, to be used as cosmetics etc., by emulsion polymerization of a vinyl compound using, as the emulsifying agent, an unsaturated polyester with its terminal carboxyl group neutralized by ammonia, followed by spray drying. CONSTITUTION:Using (A) as the emulsifying agent, a water-soluble unsaturated polyester prepared by neutralizing, with ammonia, the terminal carboxyl group of an unsaturated polyester (e.g. with a mol.wt. of 500-5,000 and acid value of 2-200mg KOH/g) to a pH of 6.5-8.0, an emulsion polymerization of (B) a vinyl compound (e.g. styrene( is carried out followed by spray drying at pref. 60-100 deg.C, thus obtaining the objective spherical crosslinked polymer powder with a size of 1-50mu. This spray drying system enables the mass production of the objective powder. |
