Process for producing plastic rods

A process for producing a plastic rod having a shape, the plastic rod comprising:

• at least an outermost profile layer;
• and
• an inner core rod within the profile;
• the process comprising:
• supplying at least a first plastic molding composition and at least a second plastic molding composition to an extruder having at least an outermost profile die and a inner rod die;
• extruding the at least first plastic molding composition through the profile die to form a profile outermost layer of the rod;
• passing the extruded profile to a calibrator;
• extruding the second plastic molding composition through a rod die to form a core rod;
• inserting the extruded core rod into the profile within the calibrator to form a newly formed rod;
• calibrating, drawing off and cooling the newly formed rod to a shape to obtain the plastic rod;
• wherein
• the second plastic molding composition comprises a thermoplastic;
• the first plastic molding composition comprises at least 50% by weight of a semicrystalline thermoplastic, and
• a crystallite melting point Tm of the first plastic molding composition is at least 170° C. in accordance with ISO 11357,
• a crystallization temperature Tk of the first plastic molding composition is at most 70 K below Tm in accordance with ISO 11357, and
• an enthalpy of fusion AH of the first plastic molding composition is at least 20 J/g in accordance with ISO 11357.