Process and catalyst component for homo- and copolymerization of

Details Process and catalyst component for homo- and copolymerization of Process and catalyst component for homo- and copolymerization of

1998-04-01

2000-03-28

Teskin, Fred

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

5261242, 5261249, 526351, 526905, 526907, 525268, C08F 4654, C08F 1000

Patent

active

060433248

DESCRIPTION:

BRIEF SUMMARY
The invention relates to a process for the homo- or copolymerization of olefins by contacting one or more polymerizable olefins having the general formula C.sub.1 -C.sub.10 alkyl, with a polymerization catalyst system obtained by contacting at least the following components: magnesium, and possibly
The invention also relates to a catalyst component intended for the polymerization of one or several olefins having the general formula C.sub.1 -C.sub.10 alkyl and which has been prepared by contacting at least the following components: magnesium, and possibly
The invention also relates to the use of a catalyst component of the above type for the polymerization of one or more olefins according to Formula (I) given above.
Olefins are commonly polymerized using a Ziegler-Natta catalyst system which comprises a so-called procatalyst and a so-called cocatalyst. The procatalyst is in the catalyst system that component which is based on a compound of a transition metal belonging any of Groups 4-10 of the Periodic Table of the Elements (IUPAC 1990), such as titanium, vanadium, chromium or zirconium. A typical procatalyst is made up of a titanium halide compound supported on a magnesium halide. The cocatalyst for its part is in the catalyst system that component which is based on an organometallic compound of a metal belonging to any of groups 1-3 and 13 of the Periodic Table of the Elements (IUPAC 1990), such as a metal hydride or a metal alkyl. A typical cocatalyst is an alkylaluminum compound. As is known, in addition to a procatalyst (including the support) and a cocatalyst, the catalyst system usually also includes agents which enhance and modify the catalytic properties, such as electron donor compounds and other auxiliaries. The function of the electron donors is to control the stereospecificity of the polymer and, when necessary, to improve the activity of the catalyst system. A large number of electron donors are known in the art, and they include ethers, esters and polysilanes or siloxanes.
It is also known that the activity and stereospecificity of the catalyst system, as well as the other properties of the polymer formed, such as its morphology and bulk density, can be affected by contacting the procatalyst and the cocatalyst, and any electron donors and other additives, before the catalyst system is used for the polymerization of an olefin or olefins. In such a case the said components of the catalyst system have been contacted outside the polymerization reaction zone and been subsequently fed into the polymerization zone and contacted therein with the olefin(s) in polymerization conditions.
It is also known that such contacting before polymerization can be carried out either before the so-called prepolymerization, or after it. In prepolymerization the particles of the catalyst system are surrounded with a small amount of polymer before they are fed into the actual polymerization zone.
Publication EP-588 277 A2 discloses a precontacting process in which a procatalyst prepolymerized by using a small amount of a monomer and a cocatalyst is contacted with a cocatalyst and an external electron donor before being introduced into the polymerization reaction zone. In this publication it is stated that the pretreated procatalyst is contacted with the cocatalyst as the procatalyst is being fed into a dilute stream of cocatalyst; this stream carries the procatalyst into the polymerization zone. According to this publication, the preferred concentration of cocatalyst in the stream is within a range of 10-30% by weight. The publication further teaches that the more cocatalyst is contacted with the procatalyst before the stream of procatalyst and cocatalyst enters the polymer reaction zone, the higher is the efficiency of the catalyst (cf. page 5, lines 8-13, of said publication).
Publication EP-517 183 A2 discloses the activation of procatalyst in olefin polymerizations in a gas phase reactor. According to this publication, all of the procatalyst, cocatalyst and external electron donor is introduced into the precontact

REFERENCES:
patent: 4376062 (1983-03-01), Hamer et al.
patent: 5075396 (1991-12-01), Kashiwa et al.
patent: 5438110 (1995-08-01), Ishimaru et al.
Publication World Polyolefin Industry (1982-83), vol. 2, pp. XIV-83 to XIV-91.

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