Recycling process of a cross-linked polymeric material, in particular from electric cable coating materials
US6127434A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 1998 |
| Grant date | Oct 3, 2000 |
| Priority date | — |
| Expiry date | Jul 23, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/62
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for dereticulating a cross-linked polymeric material, such as cross-linked polyethylene from scraps of electric cable coatings or from unused cable coatings through a mechanical mixing cycle, wherein the cross-linked material is subjected to a specific power per mass unit such as to induce shear stresses in the material itself and temperatures higher than pre-established minimum levels. At the end of this cycle the material goes back to a thermoplastic state that may be substantially regarded as thermoplastic; then, following granulation, cooling, drying and sacking, the material will be ready for re-use, either alone or mixed with virgin polymers, according to usual operating technologies for thermoplastic materials. Eventually, the mechanical mixing cycle may be preceeded by a preliminary crushing cycle of the cross-linked polymeric materials to be treated. Preferably, the mixing cycle is carried out in a twin-screw extruder with special screw and temperature profiles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.