Organic compounds -- part of the class 532-570 series – Organic compounds – Aluminum containing
Reexamination Certificate
1998-09-01
2001-03-06
Nazario-Gonzalez, Porfirio (Department: 1755)
Organic compounds -- part of the class 532-570 series
Organic compounds
Aluminum containing
C556S178000, C556S182000, C502S103000, C502S109000, C502S117000, C526S160000, C526S943000
Reexamination Certificate
active
06197985
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a solid aluminoxane for catalyst carrier, a process for preparing the same and uses thereof. More particularly, the invention relates to a low-bulk density solid aluminoxane for catalyst carrier, which is employable as an olefin polymerization catalyst component and/or a polymerization catalyst carrier, a process for preparing the solid aluminoxane, an olefin polymerization catalyst containing the solid aluminoxane, a prepolymerized catalyst for olefin polymerization containing the solid aluminoxane, an olefin polymerization process using any of those catalysts, and an olefin polymer obtained by the olefin polymerization process. The invention also relates to a process for preparing a prepolymerized catalyst for olefin polymerization wherein prepolymerized catalyst particles do not adhere to each other in the prepolymerization stage, a solid olefin polymerization catalyst component substantially containing no inorganic carrier, and an olefin polymerization process wherein an olefin is subjected to gas phase polymerization using the solid olefin polymerization catalyst component.
The meaning of the term “polymerization” used herein is not limited to “homopolymerization” but may comprehend “copolymerization”. Also, the meaning of the term “polymer” used herein is not limited to “homopolymer” but may comprehend “copolymer”.
BACKGROUND OF THE INVENTION
Olefin polymers, such as polyethylene, linear low-density polyethylene (LLDPE) which is a copolymer of ethylene and an &agr;-olefin and an ethylene/propylene terpolymer (EPT), are widely used as film forming materials and industrial materials.
The olefin polymers are produced using Ziegler catalysts or metallocene catalysts. By virtue of recent improvements of transition metal catalysts for olefin polymerization, production capacity of an olefin polymer per unit quantity of the transition metal has been rapidly increased, and as a result, catalyst removal operation after the polymerization came to be omitted.
In particular, the metallocene catalysts are highly active and are known to exhibit excellent mechanical properties of the resulting polymer such as high transparency and surface non-tackiness because of narrow molecular weight distribution. Therefore, the catalysts are coming to be practically used in solution polymerization, slurry polymerization and gas phase polymerization.
When the metallocene catalyst is used as a solid catalyst for the slurry polymerization or the gas phase polymerization, there has been made an attempt to conduct olefin polymerization in a slurry polymerization system or a gas phase polymerization system using an inorganic carrier supported type solid catalyst wherein any one or both of a metallocene catalyst component and an aluminoxane are supported on a porous inorganic oxide carrier such as silica, silica/alumina or alumina.
However, if an olefin is polymerized or copolymerized in a slurry polymerization system or a gas phase polymerization system using the inorganic carrier supported type solid catalyst, the activity per unit weight of the catalyst becomes lower than that in the solution polymerization system, because silica or the like making no contribution to the activity is contained in the catalyst.
In the polymerization of an olefin using the inorganic carrier supported type solid catalyst, further, a polymer having a relatively high bulk density is obtained. In the gas phase polymerization or the slurry polymerization, polymerization is generally carried out in a state such that a polymer is present around the active site, differently from the solution polymerization. Hence, an ununiform polymer having a wide composition distribution and/or a wide molecular weight distribution is apt to be obtained. Especially in case of polymer particles hardly having voids in the particles, distribution of monomer concentration easily takes place because of low monomer diffusion into particles, whereby an ununiform polymer is apt to be obtained.
Moreover, in the preparation of a prepolymerized catalyst, prepolymerized catalyst particles occasionally adhere to each other or to a wall of the polymerization reactor.
OBJECT OF THE INVENTION
The present invention is intended to solve such problems associated with the prior art as described above, and it is an object of the invention to provide a low-bulk density solid aluminoxane applicable as a carrier of a polymerization catalyst and to provide an olefin polymerization catalyst component capable of forming a solid olefin polymerization catalyst having high polymerization activity and high voids by being combined with a metallocene catalyst component.
It is another object of the invention to provide an olefin polymer having a narrow composition distribution and/or a narrow molecular weight distribution and to provide an olefin polymer containing a large amount of a rubber in the range of elastomer.
It is a further object of the invention to provide a process for preparing a high-void prepolymerized catalyst for olefin polymerization wherein prepolymerized catalyst particles do not adhere to each other or to a wall of the polymerization reactor.
It is a still further object of the invention to provide a solid olefin polymerization catalyst component containing no inorganic carrier such as silica, a solid olefin polymerization catalyst component having high polymerization activity and capable of producing a uniform polymer, and an olefin polymerization process comprising subjecting an olefin to gas phase polymerization in the presence of the above catalyst component.
SUMMARY OF THE INVENTION
The solid aluminoxane for catalyst carrier according to the present invention is selected from the group consisting of an aluminoxane represented by the following formula (I), an aluminoxane represented by the following formula (II) and an aluminoxane having a recurring unit represented by the following formula (IIIa) and a recurring unit represented by the following formula (IIIb) and has a bulk density of 0.01 to 1.0
wherein R is a hydrocarbon group of 1 to 10 carbon atoms, m is an integer of 2 to 500, and n and p are each an integer of 1 or more.
The solid aluminoxane for catalyst carrier preferably has an average particle diameter of 50 to 50,000 &mgr;m.
The solid aluminoxane for catalyst carrier can be obtained by bringing a solution of an aluminoxane having an alkyl group/aluminum atom ratio of not less than 1.5 into contact with a solvent insolubilizing or slightly solubilizing the aluminoxane to precipitate the aluminoxane in such a manner that at least 80% by weight based on the total amount of the aluminoxane to be precipitated is precipitated within 60 seconds from the beginning of precipitation.
The solid aluminoxane for catalyst carrier can be obtained also by causing a solution of an aluminoxane having an alkyl group/aluminum atom ratio of not less than 1.5 to react with water until the alkyl group/aluminum atom ratio of the aluminoxane becomes 1.0 to 1.5 to precipitate the aluminoxane.
In the above precipitation, the precipitation conditions are preferably controlled so that the average particle diameter of the solid aluminoxane becomes 50 to 50,000 &mgr;m.
The solid aluminoxane for catalyst carrier can be used as a n olefin polymerization catalyst component and/or a polymerization catalyst carrier by being combined with a metallocene catalyst component.
More specifically, the solid aluminoxane for catalyst carrier can be used in the form of a polymerization catalyst obtained by supporting a metallocene catalyst component (A) on the solid aluminoxane for catalyst carrier (B) or in the form of a prepolymerized catalyst obtained by prepolymerizing an olefin in the presence of the catalyst or in the presence of the catalyst and an organoaluminum compound (C).
The prepolymerized catalyst preferably has an average particle diameter of 50 to 50,000 &mgr;m and a bulk density of 0.01 to 0.2 g/cc.
The olefin polymerization process according to the present invention comprises polymerizing an olefin in the presenc
Gotoh Kazuhito
Isayama Shigeru
Kobata Atsuo
Matsumoto Tetsuhiro
Mitsui Chemicals Inc
Nazario-Gonzalez Porfirio
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