Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1995-10-19
2003-10-28
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...
C526S126000, C526S132000, C526S133000, C526S151000, C526S153000, C526S160000, C526S348500
Reexamination Certificate
active
06639030
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing an olefin polymer of high molecular weight by cloying a catalyst comprising a metallocene compound having a substituted fluorenyl group as one ligand, a cyclopentadienyl group as another ligand, and a silanediyl group forming a bridge between the two ligands at a high polymerization temperature of not lower than 120° C.
2. Description of the Related Art
In polymerization of olefin, metallocene complex catalysts are known to be highly active which comprise as fundamental constitutional components a cyclopentadienyl derivative of a transition metal such as titanium, zirconium, and hafnium (Group 4 of Periodic Table) and an aluminoxane. Such catalysts are described by J. Boor (“Ziegler-Natta Catalyst and Polymeriation”, Academic Press, New York (1979)) and by B. Sinn and W. Kaminsky (Adv. Organomet. Chem. 1899 (1980)). These catalysts are shown to be highly active in olefin polymerization and to be capable of forming a stereoregular polymer. JP-A-1-503788 (“JP-A” herein means “Japanese Patent Laid-Open Publication”) discloses a process for producing a polyethylene of high density or an ethylene/&agr;-olefin copolymer of relatively high density by employing the aforementioned catalyst system comprising a metallocene compound and aluminoxane at a high pressure and a high temperature.
These catalysts, however, are not employed in commercial production, mainly because of two disadvantages below. Firstly, aluminoxane, the cocatalyst, cannot readily be prepared with sufficient reproducibility, whereby the catalyst and the resulting polymer cannot be produced with appropriate reproducibility. Secondary, the expensive aluminoxane has to be used in an extremely high ratio to the transition metal compound, the main catalyst, in order to obtain high catalytic activity and stability of polymerization.
The above disadvantages are offset by an ionic metallocene catalyst. JP-A-3-207704 discloses an ionic metallocene compound prepared by reaction of a metallocene compound with an ionizing ionic compound. WO-92-01723 discloses a process for polymerization of a-olefin with a catalyst system prepared by reacting a halogenated metallocene compound with an organometallic compound and further bringing the resulting product into contact with an ionizing ionic compound, and describes advantages of such a catalyst system for olefin polymerization.
JP-A-5-320246 discloses high temperature polymerization with an ionic metallocene catalyst, where the polymerization catalyst is prepared from known dicyclopentadienylzirconium dichloride, dimethylanilinium tetra(pentafluorophenyl)borate, and triisobutylaluminum. However, ethylene/1-octene copolymers produced with this catalyst at high temperature have a low intrinsic viscosity, namely a low molecular weight. Therefore, the polymer produced with this catalyst is presumed to be insufficient in rigidity and strength for single use for plastics.
Generally, a polymer of a higher molecular weight is obtained at a lower polymerization temperature because of slower chain transfer reactions at a lower temperature. However, in polymerization at a temperature lower than the melting temperature of the polymer, the formed polymer deposits in the reaction vessel to retard agitation and to reduce the productivity. In solution polymerization where the polymerization is conducted at a temperature higher than the melting point of the polymer, the above disadvantages are offset, and the higher temperature gives lower viscosity of the polymerization solution to raise the agitation efficiency, thereby enabling production of a homogeneous polymer, and facilitating removal of polymerization heat and control of the reaction. In high-temperature high-pressure polymerization, the larger the difference between the temperature of polymerization and the temperature of the feed of raw materials, the higher will the olefin conversion be, and the larger will the economical profit be. Accordingly, for high temperature polymerization, the metallocene catalyst is being investigated which is active under high temperature conditions.
SUMMARY OF THE INVENTION
The present invention intends to provide a process for production of an olefin polymer having narrow composition distribution, narrow molecular weight distribution, and a high molecular weight.
The process for production of an olefin polymer of the present invention comprises polymerization of ethylene and/or &agr;a-olefin of three of more carbons at apolymerization temperature of not lower than 120° C. with a catalyst comprising:
(a) a metallocene compound having a substituted fluorenyl group represented by general formula (1):
R
1
(C
5
H
4
)(C
4
H
4-m
R
2
m
C
5
C
4
H
4-n
R
3
n
)M
1
R
4
2
(1)
wherein R
1
is a silanediyl group which forms a bridge between the C
5
H
4
group and the C
4
H
4-m
R
2
m
C
5
C
4
H
4-n
R
3
n
group to raise steric rigidity of the compound of general formula (1); C
5
H
4
is a cyclopentadienyl group; C
4
H
4-m
R
2
m
C
5
C
4
H
4-n
R
3
n
is a substituted fluorenyl group; R
2
and R
3
are independently a substituent on benzo ring moiety of the substituted fluorenyl group, and is an alkyl group, a halogenated alkyl group, an aryl group, or a halogenated aryl group; M
1
is Ti, Zr, or Hf; each of R
4
is independently a hydrogen atom, a hydrocarbon group, an amino group of 1 to 20 carbons, an oxygen-containing hydrocarbon group of 1 to 20 carbons, or a halogen; m is an integer of from 0 to 4; and n is an integer of from 0 to 4; and (b) a compound which reacts with the metallocene compound to form a cationic metallocene compound. The catalyst system may further comprise (c) an organometallic compound.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The process of the present invention is described below in detail.
The metallocene compound employed in the present invention is represented by general formula (1):
R
1
(C
5
H
4
)(C
4
H
4-m
R
2
m
C
5
C
4
H
4-n
R
3
n
)M
1
R
4
2
(1)
wherein R
1
is a silanediyl group which forms a bridge between the C5H4 group and the C4H4-mR2mC5C4H4-nR3n group to raise steric rigidity of the compound of general formula (1). The silanediyl group includes dialkylsilanediyl-groups, diarylsilanediyl groups, and alkylarylsilanediyl groups. Specifically, the dialkylsilanediyl groups include dimethylsilanediyl, diethylsilanediyl, and cyclopropylsilanediyl; and the diarylsilanediyl groups and the alkylarylsilanediyl groups include phenylmethylsilanediyl diphenylsilanediyl, ditolylsilanediyl, and dinaphthylsilanediyl. In view of suppression of molecular vibration of the substituted fluorenyl group or the cyclopentadienyl group as the ligands, preferably a single silicon atom forms a bridge between the cyclopentadienyl moiety and the 9-position of the substituted fluorenyl group, and a phenyl group derivative is bonded to the bridging atom. Such a group is exemplified by a diphenylsilanediyl group, a ditolylsilanediyl group, and a dinaphthylsilanediyl group.
The fluorenyl skeleton is represented by general formula (2):
where the attached numbers shows the positions of substitution in the fluorenyl skeleton.
R
2
and R
3
are independently a substituent on the benzo ring moiety of the substituted fluorenyl group, and is an alkyl group, a halogenated alkyl group, an aryl group, or a halogenated aryl group, specifically including groups of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, isobutyl, isopentyl, phenyl, methylphenyl, ethylphenyl, tolyl, methyltolyl, benzyl, naphthyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like, and those substituted by halogen.
M1 is Ti, Zr, or Hf.
Each of R
4
is independently a hydrogen atom, a hydrocarbon group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, isobutyl, isopentyl, phenyl, methylphenyl, ethylphenyl, tolyl, methyltolyl, benzyl, naphthyl, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; an amino group of 1 to 20 carbons su
Hasegawa Saiki
Sone Makoto
Yamada Satoru
Yano Akihiro
Teskin Fred
Tosoh Corporation
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