| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polysiloxane emulsion having a specified particle size by heating an aqueous reaction medium containing a surfactant to a specified temperature and semi-continuously adding an aqueous reaction mixture containing a siloxane precursor and an acid catalyst/surfactant to the medium. SOLUTION: The aqueous reaction medium optionally contains a surfactant. The surfactant is desirably an anionic sulfonate. This is heated to 30-110 deg.C, and an aqueous reaction mixture containing a siloxane precursor and an acid catalyst/surfactant is semi-continuously added thereto to obtain a polysiloxane emulsion having a narrow particle size distribution in the range of 50 nm to 2μm. The siloxane precursor is selected among octamethylcyclotetrasiloxane and cyclosiloxane mixtures. The acid catalyst/surfactant used is e.g. dodecylbenzenesulfonic acid and is used in an amount of 0.25-5 wt.% based on the precursor. The aqueous reaction mixture contains the both in a ratio of precursor to acid catalyst of 80/20.
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