| 摘要 |
PURPOSE:To obtain the powder improved in blocking resistance by mixing an aq. charged synthetic resin emulsion particles with oppositely charged fine inorg. particles at a ratio satisfying a given formula, then mixing the resulting mixture with an aq. synthetic vinyl resin emulsion, and then spraying the resulting mixture. CONSTITUTION:An aq. emulsion of a synthetic resin, such as a polyacrylic ester, having positively or negatively charged surfaces of the particles thereof having an average particle size of 0.01 to 50mum is mixed with a dispersion of fine inorg. particles, such as silica, having an opposite charge to that of the emulsion particles and an average particle size of at most 1/2 of that of the emulsion particles at a ratio satisfying the formula (wherein (a) is the average radius of the emulsion particles; (b) is the average radius of the fine inorg. particles; and R is the number of the fine inorg. particles/the number of the emulsion particles) to prepare an emulsion A. The emulsion A is mixed with an aq. emulsion B of a synthetic vinyl resin having a glass transition point of at most 20 deg.C and obtd. by polymn. using a water-soluble polymer as a protective colloid or by copolymn. with an unsatd. carboxylic acid at an A/B solid wt. ratio of 50 to 5/50 to 95. The resulting mixture is sprayed to obtain a blocking-resistant synthetic vinyl resin emulsion powder. |
