Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-11-05
2003-09-30
Harlan, Robert (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S129000, C526S281000, C526S282000, C526S283000, C526S336000, C526S905000, C526S916000, C526S348600, C502S152000
Reexamination Certificate
active
06627714
ABSTRACT:
The present invention relates to a method for producing an olefin type copolymer having a cyclic structure. More particularly, the present invention relates to a method which comprises copolymerizing ethylene and dicyclopentadiene or tricyclopentadiene, and, as optionally introduced, a cyclic olefin, in the presence of a catalyst system comprising a metallocene compound and an aluminoxane, whereby an olefin type copolymer having a cyclic structure, which has a high content of dicyclopentadiene or tricyclopentadiene, or a cyclic olefin, and which has a narrow molecular weight distribution, can be produced efficiently with a high catalytic activity.
An olefin type addition polymer having a cyclic structure obtainable by copolymerization of an &agr;-olefin with a cyclic olefin represented by 2-norbornene, or a so-called cyclic polyene containing at least two double bonds in its molecule (hereinafter sometimes referred to simply as a cyclic structure-containing copolymer), usually has a high glass transition temperature or high transparency as compared with an olefin type polymer containing no cyclic structure, and accordingly, it is expected to be useful for various molded products including optical materials. Various methods have been known for the production of such a ring structure-containing copolymer. With respect to a copolymer of an &agr;-olefin with norbornene and its derivatives, or a cyclic olefin such as a cyclopentadiene derivative, for example, JP-A-60-168708 or JP-A-61-271308 discloses a method of using a catalyst comprising a vanadium compound and an organic aluminum compound. However, such a method had a problem that the catalytic activity was low. As methods to have such a problem overcome, JP-A-61-221206, JP-A-64-106 and JP-A-2-173112 disclose methods of using catalysts comprising various metallocene compounds and aluminoxanes. These methods are improved from the viewpoint that the catalytic activities are relatively high, and good catalytic efficiency can be accomplished. However, the efficiency for copolymerization of the cyclic olefin to the &agr;-olefin is inadequate. Accordingly, it is desired to have the polymerization activities further improved or to have the efficiency for copolymerization of the cyclic olefin and the cyclic polyene to the &agr;-olefin improved.
On the other hand, a method for producing a cyclic structure-containing copolymer by copolymerizing an &agr;-olefin with a cyclic polyene as dicyclopentadiene or its derivative, is also known. For example, JP-A-63-243103 or JP-A-63-314220 discloses a method of employing a catalyst comprising a vanadium compound and an organic aluminum compound, and JP-A-7-70250 discloses a method of using a catalyst comprising a metallocene compound and an aluminoxane. However, these methods also had a problem that not only the catalytic activities were low, but also the efficiency for copolymerization of a cyclic polyene such as dicyclopentadiene to the &agr;-olefin was low. Thus, an industrially adequately satisfactory method has not yet been found for the production of an olefin type copolymer having a cyclic structure.
A cyclic polyene such as dicyclopentadiene or tricyclopentadiene to be used in the present invention, has two isomers i.e. an exoform isomer and an endoform isomer, and the proportion of the endoform isomer is predominant, which has a five-membered ring constituting a stereostructure closer to the ring containing a double bond to be involved in polymerization. Such a close five-membered ring constitutes a steric hindrance, whereby polymerization tends to be difficult. Further, it is known that a copolymer obtained by using, as a starting material, a cyclic polyene such as dicyclopentadiene or tricyclopentadiene, is usually susceptible to crosslinking as compared with a case where a cyclic olefin is employed, whereby a gelled polymer component is likely to be formed, and as a result, a polymer insoluble in a solvent tends to be formed. Whereas, in an application to e.g. an optical material, the uniformity of the material is important, and if such a gelled polymer component insoluble in a solvent is formed, the commercial value will be substantially impaired. Accordingly, dicyclopentadiene or tricyclopentadiene as a monomer for copolymerization, is essentially a material not preferred for the purpose of obtaining an olefin type addition polymer.
The above-mentioned gelled polymer component is likely to be formed usually when the catalytic activities are low, or when the efficiency for copolymerization of the catalyst is so poor that it is obliged to increase the charge of the cyclic polyene, or when the polymerization temperature is made high. Such a problem is attributable to an inadequate performance of the catalyst, and a catalyst having a high performance which brings about no such a problem, is desired.
Accordingly, it is an object of the present invention to provide a method whereby, even if a cyclic polyene such as dicyclopentadiene or tricyclopentadiene which is hardly copolymerizable with an &agr;-olefin, is used as a monomer material, a gelled polymer component will not be formed, the efficiency for copolymerization of a cyclic polyene and a cyclic olefin is high, polymerization activity is excellent, and still it is possible to efficiently produce an olefin type copolymer having a cyclic structure and a narrow molecular weight distribution.
The present inventors have conducted an extensive research on a method for producing an olefin type copolymer having a cyclic structure by means of a metallocene type catalyst, and as a result, have found that when a metallocene compound having a certain specific structure is combined with an aluminoxane, it is possible to solve all of the above problems and to accomplish the object of the present invention. The present invention has been accomplished on the basis of this discovery.
Namely, the present invention provides a method for producing an olefin type copolymer having a cyclic structure, which comprises copolymerizing ethylene (M1) and dicyclopentadiene or tricyclopentadiene (M2), and, as optionally introduced, a cyclic olefin (M3), wherein, as a catalyst, a catalyst comprising a metallocene compound (A) of the following formula [1]:
H
2
C(R′
m
Cp) (R″
n
Cp)MX
2
[1]
wherein M is zirconium or hafnium, Cp is a group having a cyclopentadienyl skeleton, each of R′ and R″ is a hydrocarbon group having 1 to 10 carbon atoms, each of two X's which may be the same or different from each other, is a halogen atom, a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group, an alkylamino group, an alkoxy group, an aryloxy group of the formula —O—Ar—Y
p
(wherein Ar is an aromatic ring, Y is a halogen atom, a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group, an alkoxy group, an alkylamino group, a cyano group or a nitro group, and p is an integer of from 1 to 5), a thioalkyl group, or a thioaryl group of the formula —S—Ar—Y
p
(wherein Ar, Y and p are as defined above), and each of n and m is an integer of from 0 to 4, provided that m and n are not equal, and m+n is an integer of from 3 to 6, and an aluminoxane (B), is used.
In the present invention, a specifically good result is obtained when the metallocene compound (A) is a compound wherein two cyclopentadiene rings bonded to the transition metal atom are different (asymmetric) and the two cyclopentadiene rings are bonded by a methylene group.
Now, the present invention will be described in further detail with reference to the preferred embodiments.
Among the monomer components (M2) to be used in the present invention, dicyclopentadiene is called also as 3a,4,7,7a-tetrahydro-4,7-methanoindene and is obtainable in a relatively large amount from the decomposition components of naphtha. Among the components (M2), tricyclopentadiene is a trimer of cyclopentadiene and is easily be formed by heating dicyclopentadiene at a temperature of at least 100° C. Thi
Furuyama Yoko
Kamiyama Sakae
Mizuno Kazuhiko
Suzuki Yoji
Takemori Toshifumi
Harlan Robert
Maruzen Petrochemical Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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