| 摘要 |
The invention relates to a process for the continuous extrusion forming of a thermoplastic double-walled, foam-core conduit by the sequential steps of extrusion forming an inner plastic tube, evenly coating said inner tube with foam-core layer and extrusion forming and bonding an outer tube in contact with said foam-core layer, said outer tube being generally evenly spaced apart from said inner tube by said foam-core layer providing a plastic double-walled, foam-core conduit. |
