Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2003-03-26
2004-03-09
Choi, Ling-Siu (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S348000, C526S107000, C526S128000, C526S123100, C502S103000, C502S116000, C502S126000, C502S127000, C502S115000, C502S128000
Reexamination Certificate
active
06703456
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for producing a catalyst for &agr;-olefin polymerization, and a process for producing an &agr;-olefin polymer. In more detail, the present invention relates to (1) a process for producing a highly stereoregular &agr;-olefin polymer, which has (i) a high bulk density. (ii) an extremely low content of a catalyst residue and an amorphous polymer, and (iii) an excellent mechanical property and processability, and (2) a process for producing a catalyst for &agr;-olefin polymerization, which can produce said polymer.
BACKGROUND OF THE INVENTION
There are known (1) a process for producing a catalyst for &agr;-olefin polymerization, which comprises the steps of:
(i) reducing a titanium compound containing a tetravalent titanium with an organomagnesium compound in the presence of an organosilicon compound to obtain an eutectic crystal compound of magnesium and titanium (Ti—Mg complex solid catalyst component), and
(ii) contacting the eutectic crystal compound with an organoaluminum compound and an organosilicon compound (electron donor compound): and (2) a process for producing an &agr;-olefin polymer using said catalyst (for example, JP 3-43283-B and JP 1-319508-A).
There is proposed a reduction step, wherein the above-mentioned reduction step is carried out in the presence of an ester compound in addition to the organosilicon compound.
However, each of the above-mentioned processes has a problem that the higher activity an obtained catalyst has, the lower bulk density an obtained &agr;-olefin polymer has.
As a process for producing an olefin polymer having a high bulk density, there are proposed (1) a polymerization process of ethylene using a solid catalyst component, wherein a titanlum-magnesium compound is supported on a silica gel, and (2) a polymerization process of propylene using a solid catalyst component, wherein a silica gel is impregnated with a titanium-magnesium compound.
However, those processes have problems that (1) an obtained catalyst has a low polymerization activity, and (2) an obtained polymer contains such a large quantity of silica gel that an obtained product is not preferable in view of quality and appearance.
SUMMARY OF THE INVENTION
An object of the present invention is to provide (1) a process for producing a highly stereoregular &agr;-olefin polymer, which has (1) a high bulk density, (ii) an extremely low content of a catalyst residue and an amorphous polymer, and (iii) an excellent mechanical property and processability, and (2) a process for producing a catalyst for &agr;-olefin polymerization, which can produce said polymer.
The present invention provides a process for producing a catalyst for &agr;-olefin polymerization, which comprises the steps of:
(1) reducing a titanium compound represented by the following formula (1) with an organomagnesium compound in the presence of an organosllicon compound having an Si—O bond to produce a reduction solid (hereinafter, this step is referred to as “step (1)”),
(2) aging the reduction solid for at least 18 hours in an inert solvent under stirring intermittently to produce a solid product (hereinafter, this step is referred to as “step (2)”),
(3) contacting the solid product with an ether compound, titanium tetrachloride and an organic acid halide compound, and then heating a resultant mixture to produce an organic acid halide-treated solid (hereinafter, this step is referred to as “step (3)”),
(4) contacting the organic acid halide-treated solid with a mixture of an ether compound, titanium tetrachloride and an ester compound, or with a mixture of an ether compound and titanium tetrachloride, and then heating a resultant mixture to produce a solid catalyst component containing a titanium compound (hereinafter, this step is referred to as “step (4)”), and
(5) contacting the solid catalyst component with an aluminum compound and an electron donor compound to produce a catalyst for &agr;-olefin polymerization (hereinafter, this step is referred to as “step (5)”):
Ti (OR
1
)
a
X
4-a
(1)
wherein R
1
is a hydrocarbon group having 1 to 20 carbon atoms; X is a halogen atom; and a is a number satisfying 0<a≦4.
The present invention also provides a process for producing an &agr;-olefin polymer, which comprises the step of homopolymerizing an &agr;-olefin, or copolymerizing at least one kind of an &agr;-olefin and ethylene in the presence of a catalyst for &agr;-olefin polymerization produced by the above-mentioned process.
DETAILED DESCRIPTION OF THE INVENTION
Examples of R
1
in the formula (1) are alkyl groups such asmethyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, amyl, isoamyl, tert-amyl, hexyl, heptyl, octyl, decyl and dodecyl groups; aryl groups such as phenyl, cresyl, xylyl and naphthyl groups; allyl groups such as a propenyl group; and aralkyl groups such as a benzyl group. Among them, alkyl groups having 2 to 18 carbon atoms or aryl groups having 6 to 18 carbon atoms are preferable, and straight-chain alkyl groups having 2 to 18 carbon atoms are particularly preferable. As the compound represented by the above formula (1), it is allowed to use those having two or more OR
1
groups different from one another.
As X in the formula (1), a chlorine atom, a bromine atom and an iodine atom are exemplified. Of these, a chlorine atom is particularly preferred.
A preferable a in the formula (1) is a number satisfying 2≦a≦4, and a particularly preferable a is 4.
The compound represented by the formula (1) can be produced by a process known in the art, such as (1) a process comprising the step of reacting Ti(OR
1
)
4
with TiX
4
in a predetermined ratio, and (2) a process comprising the step of reacting Tix
4
with a corresponding alcohol (for example, R
1
OH) in a predetermined ratio.
Examples of the compound represented by the formula (1) are titanium tetrahalides such as titanium tetrachloride, titanium tetrabromide and titanium tetraiodide; hydrocarbyloxytitanium trihalides such as methoxytitanium trichloride, ethoxytitanium trichloride, butoxytitanium trichloride, phenoxytitanium trichloride and ethoxytitanium tribromlde; dihydrocarbyloxytitanium dihalides such as dimethoxytitanium dichloride, diethoxytitanium dichloride, dibutoxytitanium dichloride, diphenoxytitanium dichloride and diethoxytitanium dibromide; trihydrocarbyloxytitanium monohalides such as trimethoxytitanium chloride, triethoxytitanium chloride, tributoxytitanium chloride, triphenoxytitanium chloride and triethoxytitanium bromide; and tetrahydrocarbyloxytitanium compounds such as tetramethoxytitanium, tetraethoxytitanium, tetrabutoxytitanium and tetraphenoxytitanium.
Examples of the organosilicon compound used in the present invention are compounds represented by the following formulas (2) to (4):
Si(OR
2
)
m
R
3
4-m
(2)
R
4
(R
5
2
SiO)
p
SiR
6
3
(3)
(R
7
2
SiO)
q
(4)
wherein R
2
is a hydrocarbon group having 1 to 20 carbon atoms; R
3
, R
4
, R
5
, R
6
and R
7
are independently of one another a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom; m is a number satisfying 0<m≦4; p is an integer of from 1 to 1000; and q is an integer of from 2 to 1000.
Examples of the organosilicon compound are tetramethoxysilane, dimethyldimethoxysilane, tetraethoxysilane, triethoxyethylsilane, diethoxydiethylsilane, ethoxytriethylsilane, tetra-isopropoxysilane, di-isopropoxy-di-isopropylsilane, tetrapropoxysilane, dipropoxydipropylsilane, tetrabutoxysilane, dibutoxydlbutylsilane, dicyclopentoxydiethylsilane, diethoxydiphenylsilane, cyclohexyloxytrimethylsilane, phenoxytrimethylsilane, tetraphenoxysilane, triethoxyphenylsilane, hexamethyldisiloxane, hexaethyldilsiloxane, hexapropyldisiloxane, octaethyltrisiloxane, dimethyl polysiloxane, diphenyl polysiloxane, methylhydro polyslloxane and phenylhydro polysiloxane. Among these, preferable are compounds represented by the formula (2), and among them, compounds wherein m is a number satisfying 1≦m≦4are preferable, and tetraalkoxysilane compounds wherein m&
Kaminaga Yasunori
Mori Jiro
Tanaka Tomoaki
Choi Ling-Siu
Sumitomo Chemical Company Limited
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