| Visitors to the K 2004 show in Dusseldorf this October will see automotive under-hood tubing of PP and nylon that was coinjection molded and cored out with water. The sequence starts by injecting a short shot of nylon for the outer skin, followed by PP that forms the inner layer and then water to hollow the tube and cool the inside of the part. Nylon provides heat resistance while PP, unlike nylon, provides a smooth inner surface and is immune to hydrolysis from the water/glycol engine coolant. A. Schulman GmbH in Germany, developed material for this application that is modified to improve adhesion between the PP and nylon. Tubing of this type is produced by Polytec Automotive GmbH in Idstein, Germany. It will be displayed in the Krauss-Maffei booth at the show by PME fluidtec GmbH of Germany.
PME supplies a pump system that controls the timing, pressure, and volume of water injection. It is newly available in North America from Alliance Gas Systems Inc., Chesterfield Township, Mich. Alliance also supplies gas-injection systems and holds patents on water injection. |
