Isotactic polypropylene produced from supercritical polymerization process

Abstract

This invention relates to an isotactic propylene homopolymer having: more than 15 and less than 100 regio defects (sum of 2,1-erythro and 2,1-threo insertions and 3,1-isomerizations ) per 10,000 propylene units; an Mw of 35000 g / mol or more; a peak melting temperature of greater than 149 0C; anmmmm pentad fraction of 0.85 or more; a heat of fusion of 80 J / g or more; and a peak melting temperature minus peak crystallization temperature (Tmp-Tcp) of less than or equal to (0.907 times Tmp) minus 99.64 (Tmp-Tcp < (0.907xTmp) - 99.64), as measured in 0C on the homopolymer having 0 wt% nucleating agent.

Description

[0001] Inventors: Aspy K. Mehta, Manika Varma-Nair, Gabor Kiss, Patrick Brant, Robert P. Reynolds, John W. Chu, Steven P. Rucker, and PeijunJiang technical field [0002] The present invention relates to a propylene homopolymer, preferably a propylene homopolymer prepared using a supercritical polymerization process. Background technique [0003] Metallocene catalysts have been used in high-pressure reactors since the mid-1980s, mainly for the production of ethylene-backbone polymers containing one or more of the monomers propylene, butene, and hexene Ethylene copolymers together with other specialty monomers such as 4-methyl-1,5-hexadiene. For example, US 5,756,608 (to Langhausen et al.) reports a process for the polymerization of C2-C101-alkenes using bridged metallocene catalysts. It has however been noted that the production of polypropylene under high pressure conditions is impractical and not feasible at temperatures well above the critical point of propylene. A proc...

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Problems solved by technology

This patent does not deal with the copolymerization of propylene at much higher temperature or pressure than the above

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