High melt strength polypropylene with high stiffness and clarity
US11549006B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 2018 |
| Grant date | Jan 10, 2023 |
| Priority date | — |
| Expiry date | Aug 7, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2314/02
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A polypropylene comprising within a range from 0.1 wt % to 4 wt % ethylene and/or C4 to C12 α-olefin derived units, one or more clarifiers, or both; wherein the polypropylene has a flexural modulus of at least 200 kpsi (0.05 in/min ASTM D790(A)) and an Mz/Mw of at least 4. The polypropylenes may be made by combining propylene and a comonomer with a Ziegler-Natta catalyst and at least two external electron donors, wherein the concentration of the electron donors is within a range from 1 to 100 ppm. The concentration of electron donors may be decreased to control the haze level of the polypropylene, and/or the level of comonomer derived units may be controlled to reduce the haze level of the polypropylene.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.