| 摘要 |
Disclosed are antifoam emulsions useful in control of foam in aqueous foaming systems which comprise: (A) polydiorganosiloxane; (B) fine solid particles of inorganic oxide, bearing on the surface thereof a polydiorganosiloxane component; wherein the total amount of polydiorganosiloxane present in components (A) and (B) comprises 5 wt % to 60 wt % of the emulsion and the weight ratio of the total amount of polydiorganosiloxane present in components (A) and (B) to the amount of said inorganic oxide is 10:1 to 200:1; (C) an organic surfactant dispersing agent selected from the group consisting of non-ionic tetrafunctional block copolymers terminating in primary or secondary hydroxyl groups and mixtures thereof, which agent comprises 0.1 wt % to 36 wt % of said emulsion; (D) a block copolymer of polydimethylsiloxane with one or more blocks of polyalkylene oxide, the molecular weight of the polydimethylsiloxane portion being 300 to 100,000 Daltons and the total molecular weight of all polyalkylene oxide blocks present being 100 to 40,000 Daltons, which copolymer comprises 0.1 wt. % to 20 wt. % of said emulsion; (E) a non-ionic surfactant component comprising one or more non-ionic surfactants not conforming to agent (C) nor to copolymer (D) and comprising 1 wt % to 60 wt % of said emulsion; (F) a thickener component which comprises 0.01 wt % to 15 wt % of said emulsion; (G) a protective colloid component which comprises 0.01 wt. % to 10 wt. % of said emulsion; and (H) water comprising up to 95 wt. % of the emulsion.
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