High Melt Strength Polypropylene With High Stiffness And Clarity

• Main Authors: Barry, Adrian G, Poloso, Anthony, Donahue, John M, Spofford, Caitlin A, Pehlert, George J
• Format: Patent
• Language: English
• Published: 15.10.2020
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

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.