Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-02-22
2001-10-16
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S160000, C526S161000, C526S943000, C502S104000, C502S153000, C502S155000
Reexamination Certificate
active
06303714
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an olefin polymerization catalyst component, an olefin polymerization catalyst, and a method of producing polyolefin using the catalyst. More particularly, the present invention relates to an olefin polymerization catalyst and a method of producing polyolefin using the catalyst, which catalyst has a high activity and enables one to obtain polyolefins having a wide molecular weight distribution and an excellent moldability and containing smaller amounts of low molecular weight components.
BACKGROUND OF THE INVENTION
A catalyst composed of a mixture of a metallocene compound and an organic aluminum oxy compound has been widely known as a homogeneous catalyst for polymerizing olefins. There have been made reports on olefin polymerization catalysts composed of various metallocene compounds and linear or cyclic organic aluminum oxy compounds, for example, in Japanese Patent Application Laid-open No. 19309/1983 (European Patent No. 69951), Japanese Patent Application Laid-open No. 35007/1985 (European Patent No. 129368, U.S. Pat. No. 5,324,800), Makromol. Chem., Rapid Commun. 9, 457-461 (1988), etc. However, the biscyclopentadienyl complex base catalysts used in the prior art do not give high molecular weight polyolefins when the polymerization is run at reaction temperatures of 50 to 200° C., which are efficient in industrial processes.
Japanese Patent Application Laid-open No. 2917/1995 reports that high molecular weight polyolefins are obtained by use of an amidinato complex having a trimethylsilyl group on its nitrogen atom, specific examples of which include:
bis(N,N′-bis(trimethylsilyl)benzamidinato)zirconium dichloride,
bis(N,N′-bis(trimethylsilyl)benzamidinato)zirconium ditriflate,
(cyclopentadienyl)(N,N′-bis(trimethylsilyl)benzamidinato)titanium dichloride,
(cyclopentadienyl)(N,N′-bis(trimethylsilyl)benzamidinato)zirconium chloride, and
(pentamethylcyclopentadienyl)(N,N′-bis(trimethylsilyl)benzamidinato)titanium dichloride.
However, these catalyst systems have low polymerization activities and are unsatisfactory for industrial production. Therefore, catalysts systems are desired which have high activities at reaction temperatures that are efficient in industrial processes and allowing production of high molecular weight polyolefins.
Also, it has been known that in order to increase moldability of ethylene base polymers, their melt tension needs be increased. For this purpose, study has been made on the improvement of the melt tension of ethylene base polymers with titanium base catalysts or chromium base catalysts of the Ziegler type. For example, a method of improving the moldability of ethylene base polymers obtained by a titanium catalyst of the Ziegler type by increasing their melt tension was disclosed (Japanese Patent Application Laid-open No. 90810/1981, Japanese Patent Application Laid-open No. 106806/1985).
Although the ethylene base copolymers obtained using titanium base catalysts or chromium base catalysts generally have improved melt tensions, they have a wide molecular weight distribution and contain large amounts of low molecular weight components (as evaluated by extraction with hexane) so that causes smoking when molding and molded articles tend to be sticky.
On the other hand, there has been known a method of producing polyethylene and ethylene-&agr;-olefin copolymers using a metallocene catalyst composed of a metallocene compound and methylaluminoxane. The ethylene base polymers obtained by this method have a narrow molecular weight distribution and contain small amounts of low molecular weight components so that the problem of causing smoking when molding is solved but the problem of moldability remains because of their low melt tension.
In order to solve this problem, a study has been made on the use of two types of metallocene compounds in a metallocene catalyst system to improve the melt tension of a resulting polymer. For example, a method of producing polyethylene or ethylene-&agr;-olefin copolymers has been disclosed which uses a combination of a metallocene complex having a non-crosslinking ligand and a metallocene complex having a crosslinking ligand with aluminoxane and optionally a carrier and an organic aluminum compound (Japanese Patent Application Laid-open No. 203904/1991, Japanese Patent Application Laid-open No. 213305/1992 (European Patent No. 452920)).
Further, Japanese Patent Application Laid-open No. 255436/1993, Japanese Patent Application Laid-open No. 255437/1993 (European Patent No. 515132), Japanese Patent Application Laid-open No. 155932/1993, and Japanese Patent Application Laid-open No. 155933/1993 (European Patent No. 516458) disclose methods of producing polyethylene or ethylene-&agr;-olefin copolymers which use of a catalyst system composed of two types of metallocene complexes in combination with aluminoxane and optionally an organic aluminum compound or a catalyst system obtained by prepolymerizing this catalyst.
Further, Japanese Patent Application Laid-open No. 206922/1994, Japanese Patent Application Laid-open No. 206923/1994, and Japanese Patent Application Laid-open No. 206924/1994 (European Patent No. 598628) disclose methods of producing polyethylene or ethylene-a-olefin copolymers which use of a catalyst system composed of two types of transition metal compound complexes having at least two alkyl-substituted cyclopentadienyl ligands in combination with aluminoxane and optionally a carrier and an organic aluminum compound or a catalyst system obtained by prepolymerizing this catalyst.
The ethylene base copolymers obtained by these methods have narrow comonomer distributions and contain smaller amounts of low molecular weight components so that smoking when molding is reduced and stickiness of molded articles is also improved. However, the improvement of moldability is insufficient.
Accordingly, if a method of producing at high activities an ethylene base polymer is established which has a high melt tension strength and excellent moldability, contains smaller amounts of low molecular weight components, and is free of the problem of causing smoking when molding, then such method will have a high industrial value.
Therefore, it is an object of the present invention to provide a catalyst system which has a high activity at reaction temperatures efficient for industrial processes and enables one to produce high molecular weight polyolefins.
Another object of the present invention is to provide a catalyst and a method of producing polyolefins using the catalyst, which catalyst is capable of producing polyolefin that has a wide molecular weight distribution and an excellent moldability and contains smaller amounts of low molecular weight components.
DISCLOSURE OF THE INVENTION
The present inventors have made intensive investigation to solve the above-described problems and as a result have discovered that a catalyst comprising a specified transition metal compound and an organic aluminum oxy compound or a compound which forms an ion pair with the transition metal compound can be used as a novel catalyst for the polymerization of olefins having the activity that meets the above-described objects, thus completing the present invention.
That is, the present invention provides the olefin polymerization catalyst component, the olefin polymerization catalyst containing the catalyst component, and the method of producing a polyolefin using the catalyst as described below.
1. An olefin polymerization catalyst component comprising a transition metal compound represented by general formula (1)
L
m
Cp
n
MX
1
X
2
(1)
[wherein M is a transition metal atom of Group 4 in a periodic table,
L is a group represented by general formula (2)
(wherein R
1
and R
2
, which may be the same or different, each represent an aryl group or a substituted aryl group, A and B, which may be the same or different, each represent an atom of Group 15 of the periodic table, D represents an atom of Group 14 of the periodic table, A is bonded to M, B is coordinate
Hakozaki Tsugihiko
Inazawa Shintaro
Ishida Kiyotaka
Kibino Nobuyuki
Miyake Shigenobu
Harlan R.
Japan Polyolefins Co., Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Wu David W.
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