Scrap-based method of molding plastic articles
US5776386A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 24, 1996 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Dec 24, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/911
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A molded cross-linked polyethylene article is formed using cross-linked polyethylene scrap generated in a previous extrusion process. The scrap is used, either by itself or mixed with essentially virgin cross-linkable polyethylene and a master batch mixture, to define a partially cross-linked moldable plastic material having a gel percent higher than that of the essentially virgin polyethylene used in the extrusion process. The mold used to form the scrap-based polyethylene end product has, for the essentially virgin polyethylene, a maximum acceptable plastic inflow rate. However, when the same mold is used to form the scrap-based polyethylene article, the molding problems previously associated with attempts to use polyethylene scrap in a heat-based cross-linked plastic formation process are advantageously eliminated by reducing the plastic mold inflow rate to a rate not greater than a second inflow rate less than the maximum virgin polyethylene flow rate and inversely related to the ratio of the gel percent of the scrap-based polyethylene used in the molding process to the gel percentage of the essentially virgin polyethylene.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.