Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1997-08-13
2001-02-13
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...
C526S124300, C526S124900, C526S128000, C526S908000, C502S116000, C502S125000, C502S126000, C502S127000, C502S128000
Reexamination Certificate
active
06187883
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a solid catalyst component for &agr;-olefin polymerization. More specifically, the present invention relates to a solid catalyst component for &agr;-olefin polymerization having a narrow particle size distribution and high catalytic activity, a catalyst for &agr;-olefin polymerization comprising said solid catalyst component and a process for producing poly-&agr;-olefins with said catalyst.
2. Description of the Related Arts
As is well known, the ziegler-Natta catalyst comprising a transition metal compound (IV to VI Groups) and an organometallic compound (I, II and XIII Groups) is used for producing isotactic polymers of an &agr;-olefin such as propylene, 1-butene or the like.
For the improved operability, it is desirable to produce poly-&agr;-olefins having a substantially uniform particle diameter and being free from fine powder. Catalyst residues deriving from the transition metal compound and the organometallic compound remain in the resulting poly-&agr;-olefins. An equipment for removal of the catalyst residue is required for removal and deactivation of the catalyst residue, which arises various adverse effects on the stability and processability of poly-&agr;-olefins, and the like.
the problem of the catalyst residue is solved by increasing the catalytic activity, which is defined as the weight of the produced poly-&agr;-olefin per unit weight of the catalyst. This method does not require any special equipment for removal of the catalyst residue, and reduces the production cost of poly-&agr;-olefins. The catalyst having extremely high catalytic activity is required to enable a deashing-free process that is industrially advantageous.
The higher catalytic activity, however, decreases the bulk density of the resulting polymer particles. Therefore, a catalyst having a high activity and giving polymers of high bulk density and favorably particle properties, is required. Development of the solid catalyst component having the favorable particle properties and high polymerization activity has been attempted because the particle properties of the resulting polymers significantly depend upon the particle properties of the solid catalyst component.
With respect to an improvement the particle properties and narrowing the distribution of particle size, in polymerization of ethylene, there are proposed uses of a solid catalyst component preparing by supporting a titanium-magnesium compound on a silica gel carrier to overcome the problems (JP-A-148093 and JP-A-56-47407). It is also disclosed in JP-A-62-256802 that, in polymerization of propylene, particle properties of the resulting polypropylene are markedly improved by using the solid catalyst component obtained by soaking a titanium-magnesium compound in silica gel as a carrier.
Although improving the particle properties to some extent, these proposed catalysts have relatively low activity and cause a large amount of silica gel used as the carrier to contaminate in the final products. The contaminated silica gel deteriorates the quality of final products and causes fish eye in film products.
A variety of solid catalyst components having a high catalytic activity have also been proposed.
By way of example, it is known that a Ti-Mg complex-type solid catalyst, which is obtained by reducing a tetravalent titanium compound with an organomagnesium compound in the presence of an organosilicon compound to obtain an eutectic crystal of magnesium and titanium, is used in combination with an organoaluminum compound as a co-catalyst and an organosilicon compound as a third component to realize &agr;-olefin polymerization of relatively high stereoregularity and high activity (JP-B-03-43283) and JP-A-01-319508). Another proposed technique shows that coexistence of an ester in the reduction of a tetravalent titanium compound with an organomagnesium compound in the presence of an organosilicon compound further improves polymerization of higher stereoregularity and higher activity (JP-A-216017).
Although these proposed techniques realize an extraction-free and deashing-free process, further improvement in particle properties of the resulting polymers is desired.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a solid catalyst component for &agr;-olefin polymerization, which has a high catalytic activity and a narrow distribution of particle size, contains less fine powder and is capable of giving a poly-&agr;-olefin having a high bulk density and favorable particle properties efficiently.
Another object of the present invention is to provide a solid catalyst component for &agr;-olefin polymerization and a solid for &agr;-olefin polymerization, which give a poly-&agr;-olefin having a high stereoregularity in addition to the above advantages, as well as a process for producing a poly-&agr;-olefin of favorable particle properties with said catalyst.
According to the present invention, there is provided a solid catalyst component for &agr;-olefin polymerization having a particle size distribution of not less than 6.0 in terms of the value of N in a Rosin-Rammler function of particle size distribution and giving a catalytic activity of not less than 10,000 ((g-polymer produced/g-solid catalyst component)/hour) in polymerization.
The present invention further provides (A) a solid catalyst component for &agr;-olefin polymerization containing a trivalent titanium compound, obtained by a process which comprises reducing a titanium compound represented by the general formula of Ti(OR
1
)
a
X
4-a
(wherein R
1
represents a hydrocarbon group having 1 to 20 carbon atoms; X represents a halogen atom; “a” is a number satisfying 0≦a≦4) with an organomagnesium compound in the presence of an organosilicon compound having an Si-O bond and an ester to obtain a solid product, successively adding a mixture of an ether and titanium tetrachloride and an organic acid halide in this sequence to the solid product for treatment, and further treating the treated solid product with a mixture of an ether and titanium tetrachloride or a mixture of an ether, titanium tetrachloride and an ester.
The present invention also provides a catalyst for &agr;-olefin polymerization comprising:
(A) the solid catalyst component for &agr;-olefin polymerization described above;
(B) an organoaluminum compound; and
(C) an electron-donor compound.
The present invention further provides a process for producing a poly-&agr;-olefin with said catalyst.
The present invention gives a poly-&agr;-olefin having favorable particle properties. Preferably the present invention enables high stereoregular polymerization of an &agr;-olefin.
The poly-&agr;-olefin here means a homopolymer of an &agr;-olefin or a copolymer of an &agr;-olefin and another &agr;-olefin or ethylene.
The present invention will be explained in detail below.
DETAILED DESCRIPTION OF THE INVENTION
There is described a solid catalyst component for &agr;-olefin polymerization of the present invention, which was a particle size distribution of not less than 6.0 in terms of the value of N in a Rosin-Rammler function of particle size distribution and gives a catalytic activity of not less than 10,000 ((g-polymer produced/g-solid catalyst component)/hour) in polymerization.
The factor N in the Rosin-Rammler function of particle size distribution given below is generally known as an index representing the degree of the distribution of solid particle diameter (see Rosin, P. and E. Rammler: J. Inst. Fuel, 7, p29 (1933) and Handbook of Chemical Engineering, 3rd. ed. pp. 361-362):
R(Dp)=100 exp {−(Dp/De)
N
}
wherein R(Dp) represents a residual cumulative percentage; Dp represents a particle diameter; and De represents a particle diameter corresponding to [at] R(Dp)=36.8%. The larger N tends to narrow the particle size distribution. The solid catalyst component of the large N has a narrow particle size distribution and gives a polymer having a high bulk density and favorable particle propertie
Imai Akio
Kiyota Teruyoshi
Satoh Makoto
Rabago R.
Stevens Davis Miller & Mosher L.L.P.
Sumitomo Chemical Company Limited
Wu David W.
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