Patent ID: 7960449
Filing Date: 2011-06-14
Classification: B01F,B29B,B29K

Abstract:
1. A process for the production of a polysiloxane containing mass incorporating surface treated filler materials comprising feeding materials to a change can mixer in which the materials are mixed; the change can mixer comprising a detachable mixing head assembly containing at least two spiral mixing arms extending downwardly into a can of the change can mixer, drive means for rotating the spiral mixing arms around their own axis, and drive means for rotating the spiral mixing arms as a unit around the axis of the can and wherein the geometry of the mixing arms is such that they generate downwardly directing motion on the composition being mixed, the materials being mixed to form a mixture in the change can mixer comprising: (i) a polysiloxane having more than 40 siloxane units, which is selected from the group consisting of trialklysilyl end blocked polysiloxanes, and polysiloxanes having at least one silicon bonded alkenyl group, hydroxyl group, and hydrolysable group; (ii) a reinforcing filler material selected from the group consisting of finely divided silica, surface treated finely divided silica, calcium carbonate, surface treated finely divided calcium carbonate, quartz powder, aluminium hydroxide, zirconium silicate, diatomaceous earth, and titanium dioxide; and (iii) an hydrophobing agent selected from the group consisting of disilazanes and polydiorganosiloxanes having 2-40 siloxane units having silicon bonded hydroxyl groups or amino groups; with the proviso that each of the materials (i)-(iii) are fed into the change can mixer as the material itself, or as a mixture containing one or more of materials (i)-(iii); and wherein the change can comprises one or more perforations therein.