Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Plural component system comprising a - group i to iv metal...
Reexamination Certificate
2000-02-15
2002-03-26
Wu, David W. (Department: 1713)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Plural component system comprising a - group i to iv metal...
C502S103000, C502S133000, C502S104000, C526S128000, C526S125100, C526S124300, C526S136000, C526S139000, C526S125300, C526S114000, C526S124100, C526S158000
Reexamination Certificate
active
06362124
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a component for producing an olefin polymerization catalyst, which component is hereinafter referred to as “catalyst component”, an olefin polymerization catalyst, and a process for producing an olefin polymer. More specifically, the present invention relates to (i) a catalyst component of a specific organosilicon compound, (ii) an olefin polymerization catalyst obtained using said catalyst component, which catalyst has a superior polymerization activity and a superior stereospecific polymerization efficiency in olefin polymerization, and which catalyst is suitable for obtaining an olefin polymer having an extremely low content of amorphous polymers even when hydrogen is used as a molecular weight regulator, and (iii) a process for producing an olefin polymer using said catalyst.
BACKGROUND OF THE INVENTION
It is well known that a polymer of an &agr;-olefin such as propylene and butene-1 can be produced by polymerizing an &agr;-olefin with the aid of a catalyst obtained by contacting a titanium-containing solid catalyst component with an organoaluminum compound as a promoter, which catalyst is so-called Ziegler-Natta catalyst.
The &agr;-olefin polymer obtained by such a process usually contains an amorphous &agr;-olefin polymer of industrially low utility value, as well as a highly stereospecific &agr;-olefin polymer of industrially high utility value. The amorphous &agr;-olefin polymer greatly affects mechanical properties of products such as injection-molded products, films and fibers, which are made from the &agr;-olefin polymer. In addition, the production of the amorphous polymer results in a loss of the &agr;-olefin monomer, and moreover requires any equipment for removing the amorphous polymer from the &agr;-olefin polymer. It is greatly disadvantageous from an industrial point of view. Accordingly, with respect to a catalyst used for producing an &agr;-olefin polymer, it is desirable to produce no or an extremely small amount of an amorphous polymer as a by-product.
As a catalyst capable of giving a high stereospecificity and polymerization activity, which are satisfied to a certain extent, there is known a catalyst obtained by contacting a supported-type solid catalyst component, an organoaluminum compound as a promoter and an organosilicon compound as a third component. Said supported-type solid catalyst component is obtained by supporting a tetravalent titanium halide on a magnesium halide particle (JP-A 57-63310, JP-A 58-83006 and JP-A 61-78803).
Further, as another catalyst capable of giving a high stereospecificity and polymerization activity, which are satisfied to a certain extent, there is known a catalyst obtained by contacting a solid catalyst component, an organoaluminum compound as a promoter and an electron donor compound as a third component. Said solid catalyst component is obtained by reacting an organomagnesium compound with a silicon halide compound in the presence of an ether compound to produce a solid product and then treating the solid product with an ester compound and titanium tetrachloride (JP-A 54-112983 and JP-A 56-30407).
As a third component used for the production of aforementioned catalysts, there are known tetraethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane and a cyclohexyl group-carrying compound; an alkoxysilane having a bond between a cyclopentyl group having a substituent at a specific position and a silicon atom (JP-A 8-59730); a cyclopropyl group-carrying alkoxysilane and a dicycloalkyldialkoxysilane wherein said two cycloalkyl groups are different from each other in their carbon atom numbers (JP-A 10-147610 and JP-A 10-147611); and a silicon compound having a cyclic hydrocarbon group, a branched hydrocarbon group and two alkoxy groups different from each other (JP-A 11-35620).
Each of the references referred to above is incorporated herein by reference in its entirety.
However, the aforementioned catalysts and the &agr;-olefin polymer obtained with the aid of such catalysts are not yet satisfactory in their polymerization activity and stereospecificity, respectively, and further improvements thereof are expected. Particularly, in utilities such as injection-molded products, for which high rigidity &agr;-olefin polymers are desired, it is earnestly required to develop both a catalyst having a high stereospecific polymerization efficiency and a high stereospecific polymer.
Recently, from a view point of high-speed processability of an &agr;-olefin polymer, it is also desired to obtain a catalyst capable of suppressing by-production of amorphous polymers and easily regulating the molecular weight of an &agr;-olefin polymer. In the field of high-speed processing, the lower the molecular weight of an &agr;-olefin polymer, the better flowability at the time of melt-processing. Therefore, it is desired to obtain an &agr;-olefin polymer which has a low content of amorphous polymers and has a low molecular weight.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an olefin polymerization catalyst, which has a high polymerization activity and has a high stereospecificity so that no removal of amorphous polymers is required, and moreover which can regulate the molecular weight of olefin polymers without lowering the stereospecificity thereof.
Another object of the present invention is to provide a catalyst component of a specific organosilicon compound used for producing said catalyst.
A further object of the present invention is to provide a process for producing an olefin polymer using said catalyst.
The present inventors have undertaken extensive studies relating to olefin polymerization to accomplish the aforementioned objects. As a result, it has been found that a specific organosilicon compound can accomplish the objects, and thereby the present invention has been obtained.
The present invention provides a catalyst component (C) for olefin polymerization, which is an organosilicon compound represented by the following formula (1),
wherein n is 1 or 2; R
1
, R
2
, R
3
, R
4
, R
5
and R
6
are independently of one another a hydrogen atom, a halogen atom or a hydrocarbon group, or may be bonded with one another to form a ring; R
7
is a hydrocarbon group; and when n is 2, two R
1
s, R
2
s, R
3
s, R
4
s, R
5
s and R6s may be the same or different.
The present invention also provides a catalyst for olefin polymerization, which is obtained by a process comprising the step of contacting:
a solid catalyst component (A) containing a magnesium atom, a titanium atom, a halogen atom and an electron donor compound;
an organoaluminum compound (B); and
a catalyst component (C), which is an organosilicon compound represented by the foregoing formula (1).
The present invention further provides a process for producing an olefin polymer comprising the step of polymerizing an olefin in the presence of said catalyst.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the term “polymerization” means copolymerization as well as homopolymerization, and the term “polymer” means a copolymer as well as a homopolymer.
An organosilicon compound used as the catalyst component (C) in accordance with the present invention is the one represented by the foregoing formula (1).
The symbols, R
1
R
2
, R
3
, R
4
, R
5
and R
6
in the formula (1) are preferably independently of one another a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to
Kuribayashi Hiroshi
Satoh Makoto
Choi Ling-Siu
Stevens Davis Miller & Mosher L.L.P.
Sumitomo Chemical Co,. Ltd.
Wu David W.
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