Process for making polyolefin compositions
US8349938B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 2008 |
| Grant date | Jan 8, 2013 |
| Priority date | — |
| Expiry date | Sep 1, 2029 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2205/02
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process of obtaining a thermoplastic composition formed from a polyolefin matrix is disclosed. The polyoelfin matrix comprises a polypropylene The process comprises (a) the formation of a viscoelastic mixture of the polypropylene and the lamellar mineral by heating and kneading the composition at a temperature at least equal to the working temperature of the polypropylene, (b) submitting the viscoelastic mixture to thermo-mechanical work, (c) eliminating volatile components from the viscoelastic mixture, and (d) transforming the viscoelastic mixture resulting from step (c) into a granulated material. The viscoelastic mixture is subjected during steps (a) and (b) to a weak and controlled rate of shearing of no more than 200 s−1 and the viscoelastic mixture is subjected in step (b) to at least one cycle of extension and relaxation in a dedicated zone which is at least 25% of the total length of at least one screw of a compounding extruder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.