| 摘要 |
PROBLEM TO BE SOLVED: To attain an excellent effect of growing the particles of a polymer latex containing particles of diameters as small as a specified value or below by adding a plurality of surfactants and an acid to the latex and neutralizing the acidified latex with an alkaline substance. SOLUTION: To a small-particle-diameter latex such as a polybutadiene latex having a particle diameter of 800Åor below and produced by emulsion polymerization, an emulsifier having surface activity stable under acidic conditions and comprising 0.02-0.2 pt.wt. per 100 pts.wt. polymer, anionic surfactant (e.g. sodium alkylbenzenesulfonate), about 0.001-0.006 pt.wt., per 100 pte.wt. polymer, nonionic surfactant (e.g. polyoxyethylene alkyl ether), etc., is added and mixed. The pH of the emulsion is adjusted to about 6 or below by adding at least one member selected from among hydrochloric acid, acetic acid, etc., thereto. The acidified emulsion is then neutralized with an alkaline substance (e.g. KOH) to obtain a polymer latex having a bimodal distribution with a particle diameter of 800Åor above, especially about 1,500-7,000Å.
|
