Process for producing a thermoplastic moulding compound comprising a thermoplastic copolymer a and a graft copolymer b

Abstract

The invention relates to a process for producing a thermoplastic moulding compound comprising a thermoplastic copolymer A and a graft copolymer B (), comprising: continuously drying the dewatered graft copolymer B () by supplying a drying gas () and the dewatered graft copolymer B (), by moving the dewatered graft copolymer B () through the drying gas () and forming a fluidized bed (), the drying gas () having a feed temperature Tin the range from 50° C. to 160° C., and by removing dried graft copolymer B () and an offgas (), wherein i. a starting temperature Tof the fluidized bed () on feeding () of the dewatered graft copolymer B () is measured, ii. a finish temperature Tof the fluidized bed () on removal () of the dried graft copolymer B () and/or of the offgas () is measured, iii. a difference ΔTbetween the finish temperature Tand the starting temperature Tis formed and the difference ΔTis compared with a target value ΔT, and iv. the finish temperature Tis adjusted by—increasing a mass flow rate of drying gas () supplied and/or the feed temperature Tof the drying gas () when the difference ΔTis smaller than the target value ΔTor—reducing a mass flow rate of drying gas () supplied and/or the feed temperature Tof the drying gas () when the difference ΔTis greater than the target value ΔT.