HUP9903269A3 - Process for producing thermoplastics - Google Patents

Abstract

A process for the production of impact-modified thermoplastics or thermoplastic polymer blends (I) containing (A) 5-95 wt% wet elastomer(s) containing up to 60 wt% residual water, (B) 5-95 wt% thermoplastic polymer(s), (C) 0-95 wt% other polymer(s) and (D) 0-70 wt% additives, by mixing the components in a screw machine with mechanical dewatering of component (A). The process comprises feeding the components into an extruder with at least two synchronous or contra-rotating screws with a screw diameter (Ds), comprising the following zones in the direction of feed: (a) metering section(s) in which elastomer (A) is fed in via a metering system, (b) squeezer section(s) to remove water from (A), comprising accumulator element(s) with water outlet(s) at a distance of at least one screw diameter (Ds) upstream of the (first) element, (c) feeder section(s) in which polymer (B) is introduced as a melt, (d) plastification section(s) with mixing and/or kneading elements, (e) degassing section(s) with gas outlet(s) to remove the remaining water as vapour, and (f) a discharge zone. In this process, the water leaving the dewatering outlets in zone (b) is partly or entirely in the liquid phase, and components (C) and/or (D) are fed into one or more of the above sections either together or separate from one another and together with or separate from components (A) and/or (B). Also claimed are: (i) impact-modified thermoplastic moulding materials (I) obtained by this process: and (ii) an extruder as described above.