| 摘要 |
Rubber powder is produced by mixing alkoxy group-containing organosilicon compounds with an aqueous suspension of oxide or silicate filler, mixing part of the mixture with rubber latex and acidifying to pH 6-4.5, adding the rest of the mixture and adjusting to pH 4.5-2.6, isolating the precipitated solid, washing to pH 6-7 and drying. A process for the production of finely-divided rubber (rubber powder) by precipitation from aqueous mixtures containing filler (as a suspension), water-soluble salts of Group IIa, IIb, IIIa or VIII metals and a rubber latex (polymer latex), aqueous rubber emulsion or rubber solution. This process involves: (a) mixing alkoxy group-containing organosilicon compound(s) (directly, or dissolved in water or possibly emulsified in presence of a surfactant) with an aqueous suspension of finely-divided oxide and/or silicate filler (optionally in presence of a surfactant), at 10-60 degrees C, preferably at room temperature (RT) with stirring and then dividing the amount of this mixture required in the rubber (based on filler content) into two parts; (b) mixing one part of the mixture with the polymer latex, emulsion or solution and adjusting to pH 6.0-4.5 with acid, preferably a Lewis acid; (c) adding this to the second part with further adjustment to pH 4.5-2.6, preferably 3.2, resulting in precipitation of the rubber and the silane-modified filler; (d) isolating the solid by known methods; (e) preferably washing in order to adjust the pH to a more suitable value for further processing (i.e. pH 6-7); and (f) drying the filler-containing rubber. An Independent claim is also included for rubber powder containing rubber, fillers, the usual processing aids, antioxidants, activators and/or crosslinkers and sulfur in the usual amounts. |
