Catalyst for polymerization

Details Catalyst for polymerization Catalyst for polymerization

2001-09-05

2004-01-27

Teskin, Fred (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S134000, C526S164000, C526S170000, C526S340400, C526S943000, C502S152000, C502S154000, C534S015000

Reexamination Certificate

active

06683140

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a catalyst for polymerization which is used for polymerization of a conjugated diene, copolymerization of a conjugated diene and an aromatic vinyl compound and the like.
BACKGROUND ART
Various proposals have been made so far as to polymerization catalysts for conjugated dienes, and they play a highly important role in industrial fields. In particular, various polymerization catalysts which give a high 1,4-cis-linkage content have been studied and developed to obtain conjugated diene polymers with enhanced performance in thermal and mechanical properties. For example, complex catalyst systems containing a compound of a transition metal such as nickel, cobalt and titanium as a main component are known, and some of them have already been widely used for industrial applications as polymerization catalysts for butadiene, isoprene and the like (see, End. Ing. Chem., 48, 784, 1956; Japanese Patent Publication No. 37-8198).
In order to attain a higher 1,4-cis-linkage content and superior polymerization activity, complex catalyst systems which consist of a rare earth metal compound and an organometallic compound belonging to Group I to Group III have been studied and developed, and highly stereospecific polymerization has come to be actively studied (Makromol. Chem. Suppl, 4, 61, 1981; J. Polym. Sci., Polym. Chem. Ed., 18, 3345, 1980; German Patent Application No. 2,848,964; Sci. Sinica., 2/3, 734, 1980; Rubber Chem. Technol., 58, 117, 1985 and the like.). Among these catalyst systems, complex catalysts containing a neodymium compound and an organoaluminum compound as main components were revealed to give a high 1,4-cis-linkage content and have superior polymerization activity. The catalysts have already been used industrially as polymerization catalysts for butadiene and the like (see, Macromolecules, 15, 230, 1982; Makromol. Chem., 94, 119, 1981).
With recent progress of industrial technologies, requirements for polymeric materials from a commercial viewpoint have become increasingly higher levels, and development of polymeric materials which have still higher thermal properties (thermal stability and the like) and mechanical properties (tensile modulus, bending modulus and the like) has been strongly desired. As one of promising means for achieving the object, there have been attempted to produce a polymer of a high 1,4-cis-configuration content in microstructure and a narrow molecular weight distribution by using a catalyst having a high polymerization activity for conjugated dienes.
For example, it is known that, when a samarocene complex is used as a polymerization catalyst of 1,3-butadiene and MMAO or AlR
3
/[Ph
3
C] [B(C
6
F
5
)
4
] is used in combination with the catalyst as a promoter, a polybutadiene, which is highly regulated in 1,4-cis-configuration and has a narrow molecular weight distribution, is obtained in high yields (Kaita, S., et al., Macromolecules, 32, 9078, 1999). Moreover, it has been revealed that the polymerization livingly progresses in systems using (C
5
Me
5
)
2
Sm[&mgr;-Me]AlMe(&mgr;-Me)]
2
Sm(C
5
Me
5
)
2
/Al(i-Bu)
3
/[Ph
3
C] [B(C
6
F
5
)
4
] as a catalyst, and the molecular weight of the produced polymer has become controllable (Kaita, S., et al., Polym. Prepr. Jpn., 49, 211, 2000). In addition, the compositions disclosed in the specification of PCT/JP00/1188 are known as catalyst compositions for polymerization.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a catalyst by which the polymerization of a conjugated diene or the copolymerization of a conjugated diene and an aromatic vinyl compound can be efficiently and inexpensively performed. In particular, the object of the present invention is to provide a catalyst for polymerization which is used to efficiently and inexpensively produce polymers with a high 1,4-cis-configuration content in microstructure and a narrow molecular weight distribution.
The inventors of the present invention conducted various studies to achieve the foregoing objects. As a result, they found that a polymer can be produced in a highly efficient and inexpensive manner by performing polymerization of a conjugated diene or copolymerization of a conjugated diene and an aromatic vinyl compound using a metallocene-type cation complex of a rare earth metal compound as a catalyst in the presence of an organoaluminum compound. In addition, they found that a polymer with an extremely high 1.4-cis-configuration content in microstructure and a narrow molecular weight distribution can be efficiently and inexpensively produced by using the aforementioned catalyst. The present invention was achieved on the basis of these findings.
The present invention thus provides a catalyst for polymerization of a conjugated diene or copolymerization of a conjugated diene and an aromatic vinyl compound, which comprises a metallocene-type cation complex of a rare earth metal compound. This catalyst is characterized in that the polymerization of a conjugated diene or the copolymerization of a conjugated diene and an aromatic vinyl compound can be efficiently preformed by using the catalyst in the presence of an organoaluminum compound. The catalyst is preferably provided in a solid state and added, from the outside of a reaction system into the reaction system, as a solid state or as a state of a solution obtained by dissolving the complex in a solid state as a catalyst for the polymerization of a conjugated diene or the copolymerization of a conjugated diene and an aromatic vinyl compound.
From another aspect of the present invention, there is provided a method for polymerization of a conjugated diene or copolymerization of a conjugated diene and an aromatic vinyl compound, wherein the polymerization is performed by using a metallocene-type cation complex of a rare earth metal compound in the presence of an organoaluminum compound. According to a preferred embodiment, the aforementioned metallocene-type cation complex is added as a solid state to the reaction system or added as a solution obtained by dissolving the complex in a solid state to the reaction system. From further aspect of the present invention, there is provided a use of a metallocene-type cation complex as a solid state for polymerization of a conjugated diene or copolymerization of a conjugated diene and an aromatic vinyl compound.
By using the catalyst of the present invention, a polymer can be efficiently and inexpensively obtained which has an extremely high content of 1,4-cis-configuration in the microstructure and a narrow molecular weight distribution.
BEST MODE FOR CARRYING OUT THE INVENTION
Examples of the metallocene type complex of a rare earth metal compound include trivalent rare earth metal compounds represented by the general formula (I): R
a
MX
b
wherein M represents a rare earth metal; R represents cyclopentadienyl group, a substituted cyclopentadienyl group, indenyl group, a substituted indenyl group, fluorenyl group, or a substituted fluorenyl group; X represents an anion; symbol “a” represents an integer of 1 or 2; and symbol “b” represents an integer of 1 or 2.
In the aforementioned general formula (I), an element selected from those of atomic numbers 57 to 71 in the periodic table can be used as the rare earth metal represented by M. Specific examples of the rare earth metal include lanthanium, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Among them, samarium is preferred. When the symbol “a” is 2, two of “R” may be the same or different. Similarly, when the symbol “b” is 2, two of “X” may be the same or different.
The types, numbers, and substituting positions of one or more substituents of the substituted cyclopentadienyl group, substituted indenyl group, and substituted fluorenyl group are not particularly limited. Examples of the substituent include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl

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