The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 20, 1984
Filed:
Sep. 22, 1982
Takeshi Suzuki, Ichiharashi, JP;
Hiroshi Shimizu, Chibaken, JP;
Nobutoshi Komori, Ichiharashi, JP;
Takehiro Umeno, Ichiharashi, JP;
Atsuyoshi Shimizu, Ichiharashi, JP;
Chisso Corporation, Tokyo, JP;
Abstract
A process for producing ethylene-propylene block copolymer by the use of a catalyst employed for producing isotactic polypropylene is provided. This process is characterized in that a gas phase polymerization of propylene is substantially carried out in the presence of the catalyst obtained by combining a titanium trichloride composition with an average particle size of 10.about.100 .mu. and an organic aluminum to form the propylene polymer segment with a specific surface area more than 0.015 m.sup.2 /g at a yield of more than 3,000 g per 1 g of the titanium trichloride composition in the first step, and then a gas phase polymerization of a mixture of polypropylene and ethylene is successively carried out in the second step to form the copolymer segment with a copolymerization ratio of propylene:ethylene being 5.about.80 weight %:95.about.20 weight %, wherein the polymerized amount of the second step is 10-40% of total polymerized amount and wherein normal hexane extraction ratio (75.degree. C., 1 hour) of the ethylene-propylene block copolymer powders obtained is 1.about.10 weight %. The process of the present invention is one having an extremely high productivity industrially, and the modified polypropylene obtained has a superior low-temperature-impact strength and brittle temperature.