Leading plastics processing machinery manufacturer KraussMaffei Berstorff GmbH (Germany) has developed an innovative line concept for the production of 2-component profiles made of polypropylene (PP) and thermoplastic vulcanizates (TPE-V). Two or three single-screw extruders of different size form the core elements of the co-extrusion line designed for optimum material melting and homogenizing. The first line of this type used for the production of high-quality window profiles for the new VW Golf VI has already been successfully commissioned at the customer's premises. The profiles are composed of a polypropylene profile clamping element, TPE-V sealing lips and a flock tape laminated onto the lips after the discharge from the extrusion die. The decisive benefits offered by two-component profiles are easy recycling, low part weight and reduced production cost.
The co-extrusion line features a typical V-type extruder arrangement. The primary extruder - in most cases designed as a TE 90 with a processing section length of 30 D - is used for processing the PP material. The additional single-screw extruders TE 75 and 45, with processing section lengths of 28 to 30 D each, deliver the extruded TPE-V at an angle of 45 degrees to the PP material. While the primary extruder is firmly screwed to the line, the two other extruders can be freely displaced. Thanks to this arrangement, the line can be flexibly adjusted to individual production processes. Depending on the material processed, the line achieves a production speed of up to 15 to 20 m/min. Detailed information on the new line concept will be available on the KraussMaffei Berstorff stand at the International Rubber Conference 2009 in Nuremberg (June 29 to July 2, 2009, stand 12-329).