Patent ID: 7150842

Claim:
A method of extruding a mixture of particles of a first thermoplastic and a second thermoplastic, the melting range of the first thermoplastic differing from the melting range of the second thermoplastic, using an extruder which has a heatable housing and a screw, which has an intake zone, a melting zone, a delivery zone, and a hole, extending from the intake zone up to the delivery zone, into which a temperature control medium may be introduced, said method comprising the steps of: introducing said particle mixture into said extruder; advancing said mixture through said intake, heating and delivery zones by rotation of said screw; and introducing said temperature control medium into said hole; wherein the temperature control medium causes heating of the screw in the intake zone to a temperature below the melting range of the thermoplastic having the lower melting range and causes temperature control of the screw in the delivery zone to a temperature which lies between the melting ranges of the first thermoplastic and the second thermoplastic.