Preparation of thermoplastics

A process for the preparation of toughened thermoplastics by mechanically dewatering a solid, water-moist elastomer component A containing up to 50% by weight of residual water and mixing the resulting dewatered elastomer component A' with a thermoplastic polymer B in an extruder, wherein the solid, water-moist elastomer component A is obtained by producing a dispersion of elastomer particles in an aqueous solution and partially dewatering the dispersion of the elastomer particles by a suitable dewatering method until the solid, water-moist elastomer A results, and wherein the solid, water-moist elastomer component is fed to a twin-screw extruder which has corotating screws and essentially comprises, in the transport direction,

• one unheated metering section in which elastomer component A is fed to the extruder by a metering means,
• at least one unheated squeeze section which serves for dewatering and contains at least one retarding element and in each case at least one associated dewatering orifice, wherein no Seiher barrels are used as dewatering orifices,
• at least one section in which the thermoplastic polymer B is introduced as a melt into the extruder,
• at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements,
• at least one devolatilization section which is provided with at least one devolatilization orifice and in which the residual water is removed as steam, and
• a heated discharge zone,
• and wherein the water emerging from the dewatering orifices is present partially or completely in the liquid phase.