| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject latex with number-average particle size at a specific value or lower even when using a small amount of an emulsifier by using a specific composition as a mixture of cyclic organosiloxane oligomers each composed of a specific structural unit. SOLUTION: This polyorganosiloxane-based latex with a number-average particle size of 0.008-0.1μm is obtained by emulsion polymerization pref. in an acidic state of <=pH 3 under heating to >=60 deg.C of a mixture of 0-10 wt.% of the trimer, 40-95 wt.% of the tetramer, 5-40 wt.% of the pentamer, and 0-10 wt.% of the hexamer and higher-order macromer of a cyclic organosiloxane oligomer composed of structural unit of the formula (R1 and R2 are each a 1-10C univalent hydrocarbon such as methyl ethyl or propyl) (pref. a cyclic dimethylsiloxne oligomer). Thereby, the objective latex suitable for use as e.g. an impact resistance improver, slidability-imparting agent, water repellency- imparting agent is afforded even without using a large quantity of emulsifier.
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