Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Utility Patent
1997-07-02
2001-01-02
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...
C526S169000, C526S172000, C526S281000, C526S308000, C526S309000, C526S319000, C526S331000, C526S348000, C502S117000
Utility Patent
active
06169152
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an olefin-polymerizing catalyst which comprises a transition metal compound and an organoaluminum compound, or a transition metal compound, an organoaluminum compound and an ionic compound, and to a process for producing an olefin polymer using the above olefin-polymerizing catalyst.
Polyolefins, representatives of which are polyethylene and polypropylene, and &agr;-olefin copolymers are excellent in heat resistance, aging resistance, chemical resistance and the like, and have been put into practice as general purpose resins in a broad industrial field including automobile parts.
As a process for producing the above-mentioned polyolefin, there has been known a process in which a titanium-based catalyst consisting of a titanium compound and an organoaluminum compound, a representative of which is, for example, a Ziegler-Natta catalyst; or a vanadium-based catalyst consisting of a vanadium compound and an organoaluminum compound is used. However, the process for producing a polymer with the above-mentioned titanium-based catalyst can generally produce only a polymer having a low molecular weight and a broad molecular weight distribution, and said polymer cannot be said to be satisfactory in respect of activity. In addition, the copolymer obtained using the above-mentioned titanium-based catalyst is generally inferior in random copolymerizability, so that the composition distribution of the copolymer is broad and the mechanical property cannot be said to be sufficient. Moreover, in the case of the above-mentioned vanadium-based catalyst, the random copolymerizability is enhanced, the composition distribution becomes narrow and the mechanical property is improved to some extent, but this improvement cannot still be said to be sufficient.
As a substitute for the above-mentioned prior art catalyst, there has been proposed a catalyst consisting of a transition metal compound and an aluminoxane, and, for example, JP-B 4(1992)-12,283 describes a process for polymerizing an olefin in the presence of a catalyst consisting of a transition metal compound represented by the formula:
(Cp)
2
MR
1
X
wherein Cp is a cyclopentadienyl group, R
1
is an alkyl group having 1 to 6 carbon atoms or a halogen atom, M is zirconium or titanium and X is a halogen atom, and an aluminoxane represented by the formula:
(R
2
)
2
AlO[—Al(R
2
)—O—]
n
Al(R
2
)
2
or [—Al(R
2
)O—]
n+2
wherein n is an integer of 4 to 20, R
2
is a methyl group or an ethyl group.
Furthermore, JP-B 5(1993)-80,493 describes a process for producing a copolymer having a molecular weight distribution (M
w
/M
n
) of 1.97 to 2.15 by copolymerizing ethylene with propylene or ethylene with an &agr;-olefin having 3 to 10 carbon atoms and a non-conjugated polyene having 5 to 20 carbon atoms in the presence of a catalyst consisting of an aluminoxane and a zirconium hydride compound having as a ligand a group having a conjugated &pgr;-electron.
In addition to these catalysts which are generally called metallocene catalysts, it is known that metallocene compounds cross-linked with silicon or the like (JP-A 60(1985)-35,007 and JP-A 3(1991)-12,406), geometric constraint type CGCT complex compounds (JP-A 3(1991)-163,088) and the like copolymerize ethylene with an &agr;-olefin.
Besides these metallocene catalysts, a catalyst consisting of an aluminoxane and a transition metal compound having a nitrogen-containing ligand has been proposed. For example, JP-A 2(1990)-277,412 discloses a process for copolymerizing ethylene with an &agr;-olefin in the presence of a catalyst consisting of a transition metal compound represented by the formula:
(R
1
R
2
N )
4−(m+n)
TiX
m
Y
n
wherein R
1
and R
2
represent saturated hydrocarbon groups having 8 to 30 carbon atoms, X represents a halogen, Y represents an alkoxy group, m represents 1≦m≦3, and n represents a numeral of 0≦n≦2, and an aluminoxane represented by the formula:
(R
3
)
2
AlO[—Al(R
3
)O—]
n
Al(R
3
)
2
or [—Al(R
3
)O—]
n+2
wherein n is an integer of 4 to 20 and R
3
is a methyl group or an ethyl group. Also, R. F. Jordan, et al. have synthesized a complex consisting of a center metal of Group 4 and a ligand having porphyrin-ring structure as its main chain skelton and having 4 N atoms therein (Organometallics, 14, 371, 1995) and introduced an example of polymerization of ethylene.
Besides the above, in WO96-23010, there is proposed a catalyst consisting of a diimine ligand complex having Pd or Ni as the center metal and an organoaluminum compound such as an aluminoxane or the like. This catalyst system is called a Brookhart type diimine catalyst and enables the random copolymerization of ethylene with an acyclic olefin having a polar group, a representative of which is an ester group, by addition polymerization which random copolymerization has been impossible with the above-mentioned three catalyst systems. In addition, Risse et al. have obtained a homo-addition polymer of a polycyclic olefin having a polar group, representatives of which are an ester group and a carboxyl group, with a combination of a Pd complex with a cationizing agent (Macromol. Chem., 193, 2915, 1992).
However, in each of the catalysts and polymerization methods mentioned above, there are several problems.
First of all, in the case of the transition metal compounds, representatives of which are metallocene catalysts, there is such a problem that the synthesis thereof is very complicated and is technically difficult. In the synthesis of a metallocene type ligand, its synthesis route has so many stages as 2 to 5 stages, and hence, there is a problem in an aspect of production efficiency. A mono-Cp type metallocene catalyst and a non-cross-linked di-Cp type metallocene catalyst, the synthesis of which is relatively simple, have a low activity against an &agr;-olefin and the resulting copolymer of ethylene with an &agr;-olefin has an &agr;-olefin content as low as about 5% by weight.
In addition thereto, there is such a problem that polymerization activity and high copolymerizability are not compatible with each other. An ethylene-cross-linked bisindenyl complex, which is a representative metallocene catalyst, has a high polymerization activity, but has a low &agr;-olefin copolymerizability, and an &agr;-olefin content of about 50% by wight is the upper limit. In the case of the nitrogen-containing ligand disclosed in JP-A 2(1990)-77,412 referred to above, the synthesis of a catalyst is simple and the polymerization activity is relatively high, but a high temperature and a high pressure are required as the reaction conditions therefor and severe polymerization conditions become necessary. This catalyst is also low in copolymerizability. Moreover, the Jordan et al. catalyst is low in copolymerizability of ethylene and a higher &agr;-olefin.
Furthermore, the Brookhart type catalyst is a catalyst for copolymerizing ethylene with a polar olefin which has never been seen; however, there is such a problem that the polar olefin which can be used is limited, and methyl methacrylate and alicyclic polar olefins are not polymerized. Moreover, in the case of the Risse et al. catalyst, there is no example of copolymerization of ethylene with an alicyclic polar olefin.
SUMMARY OF THE INVENTION
This invention has been made under the above-mentioned circumstances and an object of this invention is to provide an olefin-polymerizing catalyst whose catalyst components are simply synthesized, which catalyst has a high copolymerizability of an &agr;-olefin as compared with a conventional olefin catalyst and has a copolymerizability with a polar olefin, another object of this invention is to provide a process for producing an olefin polymer or copolymer using said catalyst, and still another object is to provide an olefin polymer or copolymer obtained by the process.
Other objects and advantages of this invention will become apparent from the following description.
According to this invention, there is provided an olefin-polymeriz
JSR Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Rabago R.
Wu David W.
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