Process and apparatus for manufacturing multilayer pellets

摘要

A process for manufacturing multilayer pellets (p) having a core-sheath structure with a molding material forming a sheath (b) which covers around the outer circumference of another molding material forming a core (a), which comprises (a): supplying the core material and the sheath material to a die equipment (3) having a plurality of extrusion-forming parts arranged along a circumference, (b): extruding a plurality of multilayer strands (S) from the extrusion-forming parts by covering around the outer circumference of the core material (a) concentrically with the sheath material (b), and (c): cutting (6) the extruded multilayer strands (S) to manufacture multilayer pellets (p); a die equipment (3) used for the above process; a master-batch pellet with improved brittleness, having such a core-sheath structure wherein 80 wt% or more of the pigments and/or additives are contained in the core layer; a process for producing the master-batch pellet; and a process for drying thermoplastic polyester resin, which comprises drying multilayer pellets having a core-sheath structure in which a thermoplastic resin which does not cause blocking at the drying temperature is used as the sheath; are provided.