Process for manufacturing multilayer pellets and use of the multilayer pellets

A process for manufacturing multilayer pellets having a core-sheath structure with a molding material forming a sheath which covers around an outer circumference of another molding material forming a core, which comprises:

• (a) providing a die equipment, which comprises:
• a core-material supply port for feeding core material,
• a sheath material supply port for feeding sheath material,
• a plurality of extrusion-forming sections which are arranged at a plurality of places along a circumference and extrudes the core material and the sheath material so that the sheath material concentrically covers around the outer circumference of the core material,
• a core material supply route for supplying the core material from the core material supply port to a center of each extrusion-forming section, which extends first from the core material supply port to a center axis of the circumference on which the plurality of extrusion-forming sections are arranged, and thereafter, extends in a radial direction from the center axis towards each extrusion-forming section, and
• a sheath material supply route for supplying the sheath material from the sheath material supply port to the outer circumference of the core material in each extrusion-forming section, which extends first from the sheath material supply port to the center axis of the circumference on which the plurality of the extrusion-forming sections are arranged, and thereafter, extends in the radial direction from the center axis towards each extrusion-forming section;
• (b) supplying the core material and the sheath material to the core material supply port and the sheath material supply port, respectively;
• (c) extruding a plurality of multilayer strands from the extrusion-forming sections by covering around the outer circumference of the core material concentrically with the sheath material;
• and
• (d) cutting the extruded multilayer strands to manufacture multilayer pellets,
• wherein the process extrudes a thermoplastic resin and at least one compound (A) selected from pigments or additives into the strands so that 80 wt % or more of the compound (A) is contained in the core.