GB2126593A - Olefin polymerisation catalysis - Google Patents

Abstract

An olefin polymerization is carried out by using a catalyst obtained from the following components [I], [II] and [III]: [I] a solid substance obtained by the reaction of the following (i) through (iv): (i) a magnesium halide, (ii) a compound represented by the general formula Me(OR)nXz-n wherein Me is an element selected from Groups I through VIII of the Periodic Table, provided silicon, titanium and vanadium are excluded, R is a hydrocarbon radica) having 1 to 24 carbon atoms, X is a halogen atom, z is the valence of Me and n is 0 < n </= z, (iii) a compound represented by the formula R min mSi(OR sec )nX4- m-n wherein R min and R sec are each a hydrocarbon radical having 1 to 24 carbon atoms, X is a halogen atom, m and n are 0 </= m < 4 and 0 < n </= 4, provided 0 < m + n </= 4, and (iv) a titanium compound and/or a vanadium compound; [II] a compound represented by the general formula <IMAGE> wherein R<1>, R<2> and R<3> are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen or halogen, R<4> is a hydrocarbon radical having 1 to 24 carbon atoms and q is 1 </= q </= 30 and [III] an organometallic compound.

Description

SPECIFICATION Process for preparing polyolefins Background of the invention The present invention relates to a process for preparing polyolefins using a novel polymerization catalyst.

Heretofore, in this technical field there has been known from Japanese Patent Publication No. 12105/1964 a catalyst which comprises a magnesium halide and a transition metal compound such as a titanium compound supported thereon, and also known from Belgian Patent No.742,112 a catalyst obtained by co-pulverizing a magnesium halide and titanium tetrachloride.

However, when viewed from the standpoint that as high a catalytic activity as possible is desired in the production of polyolefins, the process disclosed in the Japanese Patent Publication 12105/1964 is still unsatisfactory in point of polymerization activity, and the process of the Belgian Patent 742,112 gives a fairly improved polymerization activity, but still leaves room for improvement.

In West German Patent No. 2137872, the amount of a magnesium halide used is substantially decreased by the co-pulverization of the magnesium halide with titanium tetrachloride and alumina. But a remarkable increase in activity per solid which can be regarded as the guideline for productivity is not recognized, thus leading to a desire for catalyst of higher activity.

In the preparation of polyolefins, moreover, it is desirable from the aspects of productivity and slurry handling that the bulk density of the resultant polymer be as high as possible. When viewed from this standpoint, the process disclosed in the foregoing Japanese patent publication 12105/1964 affords polymers low in bulk density and is not satisfactory in point of polymerization activity, and the process of the Belgian patent 742,112 is also disadvantageous in that the bulk density of the resultant polymer is low, although it affords a high polymerization activity. Thus, in both processes, a further improvement is desired.

Summary of the invention It is an object of the present invention to remedy the above-mentioned drawbacks of the prior art.

It is another object of the present invention to provide a process for preparing a novel polymerization catalyst which exhibits a high polymerization activity, which is capable of affording a polymer of high bulk density in high yield and which permits an extremely easy execution of a continuous polymerization, as well as a process for homo- or copolymerizing olefins in the presence of the said polymerization catalyst.

According to the present invention there is provided a process for preparing a polyolefin, characterized by polymerizing at least one olefin in the presence of a catalyst, which catalyst comprises either the following combination (1) or (2): (1) [I] a solid substance obtained by the reaction of (i) a magnesium halide, (ii) a compound represented by the general formula Me(OR)nXz~n wherein Me is an element of Groups I through VIII of the Periodic Table, provided silicon, titanium and vanadium are excluded, R is a hydrocarbon radical having 1 to 24 carbon atoms, Xis a halogen atom, z is the valence of Me and n is0 < n ~ (iii) a compound represented by the general formula R'mSI(OR")nX4-m-n wherein R' and R" are each a hydrocarbon radical having 1 to 24 carbon atoms, Xis a halogen atom, m and n are 0' m < 4 and 0 < n' 4, provided 0 < m + n - 4, and (iv) a titanium compound and/or a vanadium compound; II. a compound represented by the general formula

wherein R1, R2 and R3 are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen or halogen, R4 is a hydrocarbon radical having 1 to 24 carbon atoms and q is 1 = q =' 30; and [III] an organometallic compound.

(2) [I] a solid substance obtained by the reaction of (i) a magnesium halide, (ii) a compound represented by the general formula Me(OR),X,-, wherein Me is an element of Groups I through VIII of the Periodic Table, provided silicon, titanium and vanadium are excluded, R is a hydrocarbon radical having 1 to 24 carbon atoms, Xis a halogen atom, z is the valence of Me and n isO < n =' (iii) a compound represented by the general formula R'mSl(OR")nX4-m-n wherein R' and R" are each a hydrocarbon radical having 1 to 24 carbon atoms, Xis a halogen atom, m and n are 0 = m < 4 and 0 < n =' 4, provided 0 < m + n =' 4, and (iv) a titanium compound and/or a vanadium compound; and [II] a product obtained bythe reaction of (v) a compound represented by the general formula

wherein R1, R2 and R3 are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen or halogen, R4 is a hydrocarbon radical having 1 to 24 carbon atoms and q is 1 = q = 30, and (vi) an organometallic compound.

The catalyst of the present invention exhibits a very high polymerization activity, resulting in a decreased partial pressure of monomer during polymerization, affords a polymer having a high bulk density, thus permitting improvement of productivity, remains in the resultant polymer after polymerization in an extremely small quantity to the extent that the polyolefin manufacturing process can dispense with the catalyst removing steps, resulting in a more simplified step for polymer treatment, and thus permits an extremely economical production of polyolefins as a whole.

According to the process of the present invention, the amount of polymer produced per unit polymerization reaction vessel is large because of a high bulk density of the polymer.

Further, when viewed from the standpoint of particle size of the resulting polymer, the proportion of coarse particles and fine particles below 50 is low despite of a high bulk density of the polymer, thus permitting an easy execution of a continuous polymerization reaction and an easy handling of polymer particles, for example, in centrifugal separation in the polymer treating step or in transportation of the powdered polymer.

As a further advantage of the present invention, mention may be made of an outstanding effect on economy and on productivity. More particularly, polyolefins prepared by using the catalyst of the present invention have a high bulk density as previously noted, and less hydrogen concentration is required than in the prior art process for obtaining a polymer having a desired melt index, thus resulting in that the total pressure can be maintained at a relatively small level throughout the polymerization.

Moreover, in the polymerization of olefin using the catalyst of the present invention, the decrease of the olefin absorbing rate is not accelerated with the lapse of time, so the polymerization can be continued for a long time in a small quantity of the catalyst.

Additionally, polymers prepared by using the catalyst of the present invention are extremely narrow in molecular weight distribution and their hexane extraction is very small, that is, the by-production of low polymers is minimized. Consequently, it is possible to obtain products of good quality, for example, a product superior in anti-blocking property in film grade.

Thus, the catalyst of the present invention is a novel catalyst which has many such characteristic features and which has remedied the above-mentioned drawbacks of the prior art. And it is quite surprising that the foregoing features can easily be attained by using the catalyst of the present invention.

Description ofpreferred embodiments As the magnesium halide used in the present invention there is used a substantially anhydrous one, examples of which include magnesium fluoride, magnesium chloride, magnesium bromide and magnesium iodide, with magnesium chloride being particularly preferred.

As examples of the compound represented by the general formula Me(OR)nXz~n used in the present invention wherein Me, z, n and Rare as previously defined, mention may be made of such various compounds as NaOR, Mg(OR)2, Mg(OR)X, Ca(OR)2, Zn(OR)2, Zn(OR)X, Cd(OR)2, Al(OR)3, Al(OR)2X, B(OR)3, B(OR)2X, Ga(OR)3, Ge(OR)4, Sn(OR)4, P(OR)3, Cr(OR)2, Mn(OR)2, Fe(OR)2, Fe(OR)3, Co(OR)2 and Ni(OR)2, and as more preferable concrete examples there may be mentioned such compounds as NaOC2H5, NaOC4H9, Mg(OCH3)2, Mg(OC2H5)2, Mg(OC3H5)2, Ca(OC2H5)2, Zn(OC2H5)2, Zn(OC2H5)CI, Al(OCH3)3, Al(OC2H5)3, Al(OC2H5)2CI, Al(OC3H7)3, Al(OC4Hg)4, Al(OCeH5)3, B(OC2H5)3, B(OC2H5)2CI, P(OC2H5)3, P(OCsH5)3 and Fe(OC4H9)3.

Compounds represented by the general formulae Mg(OR)nX2~n, Al(OR)nX3~n and B(OR)nX3-n are particularly preferred in the present invention. And as the substituent R, alkyl groups having 1 to 4 carbon atoms and phenyl group are especially preferred.

To exemplify the compound represented by the general formula R'mSi(OR")nX4~m~n used in the present invention wherein R', R", m and n are as previously defined, mention may be made of the following: monomethyltrimethoxysilane, monomethyltriethoxysilane, monomethyltri-n-butoxysilane, monomethyltrisec-butoxysilane, monomethyltriisopropoxysilane, monomethyltripentoxysilane, monomethyltrioctoxysi lane, monomethyltristearoxysilane, monomethyltriphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropoxysilane, dimethyldiphenoxysilane, trimethylmonoethoxysilane, trimethylmonoethoxysilane, trimethylmonoisopropoxysilane, trimethylmonophenoxysilane, monomethyldimethoxymonochlorosilane, monomethyldiethoxymonochlorosilane, monomethylmonoethoxydichlorosilane, monomethyldiethoxymonochlorosilane, monomethyldiethoxymonobromosilane, monomethyldiphe noxymonochlorosilane, dimethylmonoethoxymonochlorosilane, monoethyltrimethoxysilane, monoethyltriethoxysilane, monoethyltriisopropoxysilane, monoethyltriphenoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiphenoxysilane, triethylmonomethoxysilane, triethylmonoethoxysilane, triethylmonophenoxysilane, monoethyldimethoxymonochlorosilane, monoethyldiethoxymonochlorosilane, monoethyldiphenoxymonochlorosilane, monoisopropyltrimethoxysilane, mono-n-butyltrimethoxysilane, mono-n-butyltriethoxysilane, mono-sec-butyltriethoxysilane, monophenyltriethoxysilane diphenyldiethoxysilane, diphenylmonoethoxymonochlorosilane, monomethoxytrichlorosilane, monoethoxytrichlorosilane monoisopropoxytrichlorosilane, mono-n-butoxytrichlorosilane, monopentoxytrichlorosilane, monooctoxytrichlorosilane, monostearoxytrichlorosilane, monophenoxytrichlorosilane, mono-p-methylphenoxytrichlorosilane, dimethoxydichlorosilane, diethoxydichlorosilane, diisopropoxydichlorosilane, triethoxymonochlorosilane, triisopropoxy monochlorosilane, tri-n-butoxymonochlorosilane, tri-sec-butoxymonochlorosilane, tetraethoxysilane and tetraisopropoxysilane.

As examples of the titanium compound and/or vanadium compound used in the present invention, there may be mentioned halides, alkoxyhalides, alkoxides and halogenated oxides oftitanium and/or vanadium.

Suitable examples of titanium compounds are tetravalent and trivalent titanium compounds. As tetravalent titanium compounds are preferred those represented by the general formula Ti(OR)pX4~p wherein R is an alkyl, aryl or aralkyl group having 1 to 24 carbon atoms, X is a halogen atom and p isO =' p = 4, such as, for example, titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monomethoxytrichlorotitanium, dimethoxydichlorotitanium, trimethoxy monochlorotitanium, tetramethoxytitanium, monoethoxy trichlorotitanium, diethoxydichlorotitanium, triethoxymonochlorotitanium, tetraethoxytitanium, monoisopropoxytrichlorotitanium, diisopropoxydichlorotitanium, triisopropoxymonochlorotitanium, tetraisopropoxytitanium, monobutoxytrichlorotitanium, dibutoxydichlorotitanium, monopentoxytrichlorotitanium, monophenoxytrichlorotitanium, diphenoxydichlorotitanium, triphenoxymonochlorotitanium and tetraphenoxytitanium. To illustrate trivalent titanium compounds, mention may be made of titanium trihalides obtained by reducing titanium tetrahalides such as titanium tetrachloride and titanium tetrabromide with hydrogen, aluminum, titanium or an organometallic compound of a metal of Groups I through Ill in the Periodic Table, as well as trivalent titanium compounds obtained by reducing tetravalent alkoxytitanium halides of the general formula Ti(0R)rX4-rwith an organometallic compound of a metal of Groups I through Ill in the Periodic Table, in which formula R is an alkyl, aryl or aralkyl group having 1 to 24 carbon atoms and r is 0 < r < 4. As examples of vanadium compounds, there are mentioned tetravalent vanadium compounds such as vanadium tetrachloride, vanadium tetrabromide, vanadium tetraiodide and tetraethoxyvanadium; pentavalent vanadium compounds such as vanadium oxytrichloride, ethoxydichiorovanadyl, triethoxyvanadyl and tributoxyvanadyl; and trivalent vanadium compound such as vanadium trichloride and vanadium triethoxide.

Tetravalent titanium compounds are most preferred in the present invention.

In order to make the present invention more effective, both the titanium compound and the vanadium compound are often used in combination. In this case, it is preferable that the V/Ti molar ratio be in the range of 2/1 to 0.01/1.

As examples of the compound of the general formula

used in the present invention, mention may be made of the compound of the general formula 9'mSi(OR")nX4-m.n which is used in the catalyst component [I], as well as chain-like or cyclic polysiloxanes with a recurring unit represented by

obtained by condensation of the compounds R'mSi(OR")nX4-m-n. The method for obtaining the component [I] by reacting (i) a magnesium halide, (ii) a compound of the general formula Me(OR)nXz~n, (iii) a compound of the general formula R'mSi(OR")nX4~mn and (iv) a titanium compound and/or a vanadium compound, is not specially limited.For example, these constituents may be contacted together and thereby reacted under heating at a temperature ranging from 20 to 400"C, preferably 50 to 300"C, usually for 5 minutes to 20 hours in the presence or absence of an inert solvent, or they may be reacted by a co-pulverization treatment, or may be reacted by a combination of these methods. The reaction order of the constituents (i) - (iv) is not specially limited, either.

As the inert solvent, which is not specially limited, there may be used hydrocarbon compounds and/or derivatives thereof which do not inactivate Ziegler type catalysts. Examples are saturated aliphatic hydrocarbons, aromatic hydrocarbons and alicyclic hydrocarbons, such as propane, butane, pentane, hexane, heptane, octane, benzene, toluene, xylene and cyclohexane, as well as alcohols, ethers and esters such as ethanol, diethyl ether, tetrahydrofuran, ethyl acetate and ethyl benzoate.

In case a co-pulverization treatment is adopted for the reaction, the apparatus for the co-pulverization is not specially limited, but usually employed is a ball mill, a vibration mill, a rod mill or an impact mill.

Conditions such as the pulverizing temperature and time can be decided easily by those skilled in the art according to how to pulverize. Generally, the pulverizing temperature ranges from 0 to 200"C, preferably 20 to 1 OO"C, and the pulverizing time ranges from 0.5 to 50 hours, preferably 1 to 30 hours. Of course, the co-pulverizing operation should be preformed in an inert gas atmosphere, and moisture should be avoided as far as possible.

As to the mixing ratio of the magnesium halide and the compound of the general formula Me(OR)nXz~n and a too large amount thereof tend to result in lowering of the polymerization activity. A desirable range for the production of a high activity catalyst is from 1/0.001 to 1/20, preferably 1/0.01 to 1/1 and most preferably 1/0.05 to 1/0.5 in terms of Mg/Me molar ratio.

As to the mixing ratio of the magnesium halide and the compound of the general formula R'mSi(OR")nX4~m~n, both a too large amount of the compound of the general formula R'mSi(OR")nX4~m~n and a too small amount thereof would not be effective. A desirable range is from 1/0.01 to 1/1, preferably 1/0.05to 1/0.5, in terms of Mg/Si molar ratio.

As to the amount of the titanium compound and/or vanadium compound, most preferably it is adjusted so that the amount of titanium and/or vanadium contained in the catalyst component [I] is in the range of 0.5 to 20 wt.%. The range of 1 to 10 wt.% is especially desirable for attaining a well-balanced activity per titanium and/or vanadium and that per solid.

As to the amount of the compound represented by the general formula

which is used as the catalyst component [II] in the present invention, both too large and too small amounts thereof would not be effective. Usually, it is used in the range of 0.1 to 100 moles, preferably 0.3 to 20 moles, per mole of the titanium compound and/or vanadium compound in the catalyst component [I].

It is also preferable in the present invention that the catalyst component [I] thus obtained be supported on an oxide of a metal of Groups II through IV in the Periodic Table. As such oxide, there may be used not only oxides of metals of Groups II through IV in the same Table but also double oxides thereof; of course, mixtures thereof are employable. Examples are MgO, CaO, ZnO, BaO, SiO2, SnO2, Al2O3, MgO.Al2O3, SiO2.Al2O3, MgO.SiO2, MgO.CaO.A1203 and Al203.CaO, with SiO2, Al2O3, SiO2.AI203 and MgO.A1203 being especially preferred.

The method for supporting the catalyst component [I] on the said metal oxide is not specially limited. As a preferable example, there may be adopted a method in which the constituents (i), (ii), (iii) and (iv) are allowed to react under heating in an ether compound as solvent in the presence of the said metal oxide and then the liquid phase portion is removed, or a method in which a product obtained by co-pulverization of the constituents (i) and (ii) is allowed to react under heating in an ether compound as solvent in the presence of the said metal oxide, then the liquid phase portion is removed and thereafter the constituents (iii) and (iv) are reacted therewith in an inert solvent under heating.

As examples of the organometallic compound used in the present invention, there may be mentioned organometallic compounds of metals of Groups I through IV in the Periodic Table which are known as a Ziegler catalyst component. Especially preferred are organoaluminum compounds and organozinc compounds.Concrete examples are organoaluminum compounds of the general formulae R3AI, R2AIX, RAIX2, R2AIOR, RAI(OR)X and R3AI2X3 wherein the Rs, which may be alike or different, are each an alkyl or aryl group having 1 to 20 carbon atoms and Xis a halogen atom, and organozinc compounds of the general formula R2Zn wherein the Rs, which may be alike or different, are each an alkyl group having 1 to 20 carbon atoms, such as triethylaluminum, triisopropylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diisopropylaluminum chloride, ethylaluminum sesquichloride, diethylzinc, and mixtures thereof.Together with these organometallic compounds there may be used organic carboxylic acid esters such as, for example, ethyl benzoate, ethyl o- or p-toluylate and ethyl p-anisate.

The amount of the organometallic compound used is not specially limited, but usually ranges from 0.1 to 1,000 moles per mole of the titanium compound and/or vanadium compound.

In the present invention, moreover, the compound of the general formula

may be reacted with the above-exemplified organometallic compound and the product thereby obtained may be used. In this case, the reaction ratio is in the range of 1: 500 to 1:1, preferably 1:100 to 1: 2, in terms of the compound of the said general formula : the organometallic compound (molar ratio).

The product obtained by the reaction of the compound of the general formula

with the organometallic compound is used in an amount ranging preferably from 0.1 1 to 100 1 and more preferably 0.3 1 to 20:1 in terms of Si : Ti and/or V (molar ratio) with respect to the titanium compound and/orvanadium compound in the catalyst component [I].

The olefin polymerization using the catalyst of the present invention may be performed in the form of slurry polymerization, solution polymerization or vapor phase polymerization, with the vapor phase polymerization and slurry polymerization being particularly suitable. The polymerization reaction is carried out in the same way as in the conventional olefin polymerization reaction using a Ziegler type catalyst. That is, the reaction is performed in a substantially oxygen- and water-free condition and in the presence or absence of an inert hydrocarbon. Olefin polymerizing conditions involve temperatures ranging from 20 to 1200C, preferably 50 to 100"C, and pressures ranging from atmospheric pressure to 70 kg/cm2, preferably 2 to 60 kg/cm2.Adjustment of the molecular weight can be done to some extent by changing polymerization conditions such as the polymerization temperature and the catalyst molar ratio, but the addition of hydrogen into the polymerization system is more effective for this purpose. Of course, using the catalyst of the present invention there can be performed, without any trouble, two- or more-stage polymerization reactions involving different polymerization conditions such as different hydrogen concentrations and different polymerization temperatures.

The process of the present invention is applicable to the polymerization of all olefins that are polymerizable with a Ziegler catalyst. Particularly, a-olefins of C2 to C12 are preferred. For example, the process of the invention is suitable for the homopolymerization of such a-olefins as ethylene, propylene, butene-1, hexene-1,4-methyl pentene-1 and octene-1 ,the copolymerization of ethylene and propylene, ethylene and butene-1, ethylene and hexene-1, ethylene and 4-methylpentene-1, ethylene and octene-1, and propylene and butene-1, as well as the copolymerization of ethylene and two or more other a-olefins.

Copolymerization with dienes for the modification of polyolefins is also preferable, for example, with butadiene, 1,4-hexadiene, ethylidene norbornene and dicyclopentadiene.

The following examples serve to illustrate the invention in more detail, but should not be construed as limiting the invention thereto.

Example 1 (a) Preparation of solid catalyst component[l] 10 g. of a commercially available anhydrous magnesium chloride, 2.3 g. of aluminum triethoxide, 3.2 g. of tetraethoxysilane and 2.5 g. of titanium tetrachloride were placed in a stainless steel pot having a content volume of 400 ml. and containing 25 stainless steel balls each 1/2 inch (12.7 mm) in diameter, and ball-milled for 16 hours at room temperature in a nitrogen atmosphere to obtain a solid catalyst component [I] containing 35 mg. of titanium per gram thereof.

(b) Polymerization As a vapor phase polymerization apparatus there was used a stainless steel autoclave, and a loop was formed by using a blower, a flow control device and a dry cyclone. The temperature of the autoclave was adjusted by passing warm water through its jacket.

Into the autoclave adjusted to 80 C were fed the above solid catalyst component [I], monomethyltriethoxysilane and triethylaluminum at rates of 50 mg/hr, 0.2 mmol/hr and 5 mmol/hr, respectively, and further fed were butene-1, ethylene and hydrogen gases while adjusting the butene-1/ethylene ratio (molar ratio) in the vapor phase in the autoclave to 0.28 and the hydrogen concentration to 17% of the total pressure, and polymerization was carried out while maintaining the total pressure at 10 kg/cm2.G by circulating the intra-system gases by means of the blower, to afford an ethylene copolymer having a bulk density of 0.35, a melt index (MI) of 1.0 and a density of 0.9217. Catalyst activity was 294,0009. copolymer/g.Ti.

After a continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

F.R. value (F.R. = MllO/M12.16) represented in terms of the ratio of a melt index (Ml10) of the copolymer determined at a load of 10 kg. to a melt index (MI2.15) thereof determined at a load of 2.16 kg. both at 190"C according to the method of ASTM-D1238-73 was 6.7 and thus the molecular weight distribution was extremely narrow.

When a film formed from this copolymer was extracted in boiling hexane for 10 hours, its hexane extraction was 0.5 wt.% and thus was very small.

Comparative Example 1 A continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same way as in Example 1 except that the monomethyltriethoxysilane was not added, to afford an ethylene copolymer having a bulk density of 0.30, a density of 0.9210 and a melt index of 1.3. Catalytic activity was 310.000g.copolymer/g.Ti.

The F.R. value of this copolymer was 7.3, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction was 1.6 wt.%.

Example 2 10 ml. of ethanol, 20 g. of an anhydrous magnesium chloride and 4.6 g. oftriethoxyboron were charged into a three-necked 300 ml. flask equipped with a magnetic induction stirrer and allowed to react for 3 hours under reflux. Thereafter, 150 ml. of n-hexane was added to allow precipitation to take place. Then, after standing, the supernatant liquid was removed, followed by vacuum drying at 200"C to obtain a white dry powder.

11 g. of the above white powder, 3.0 g. of diethoxydiethylsilane and 2.4 g. of titanium tetrachloride were placed in a stainless steel pot having a content volume of 400 ml. and containing 25 stainless steel balls each 1/2 inch (12.7 mm) in diameter, and ball-milled for 16 hours at room temperature in a nitrogen atmosphere, to give a solid catalyst component [I] containing 39 mg. of titanium per gram thereof.

A continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same way as in Example 1 except that the above solid catalyst component [I] was fed at a rate of 50 mg/hr, to afford an ethylene copolymer having a bulk density of 0.33, a density of 0.9220 and a melt index of 1.2. Catalytic activity was 340,000g.copolymer/g.Ti and thus very high.

After the continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

The F.R. value of this copolymer 6.9, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction was 0.8 wt.% and thus very small.

Example3 10 g. of an anhydrous magnesium chloride, 3.1 g. of diethoxymagnesium and 2.9 g. of titanium tetrachloride were placed in the ball mill pot described in Example 1, and ball-milled for 5 hours at room temperature in a nitrogen atmosphere, then 3.8 g. of methyltriethoxysilane was added, followed by further ball milling for 12 hours, to give a solid catalyst component [I] containing 37 mg. of titanium per gram thereof.

A continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same way as in Example 1 except that the solid catalyst component [I] just prepared above was fed at a rate of 50 mg/hr and a mixture obtained by reacting triethylaluminum and tetraethoxysilane at a ratio of 1 mole triethylaluminum and 0.1 mole tetraethoxysilane at 85"C for 2 hours was fed at a rate of 5 mmol/hr as aluminum, to afford an ethylene copolymer having a bulk density of 0.34, a density of 0.9215 and a melt index of 0.95. Catalytic activity was 258,000g.copolymer/g.Ti and thus very high.

After the continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

The F.R. value of this copolymer was 6.7, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction was 0.4 wt.% and thus very small.

Example 4 10 g. of an anhydrous magnesium chloride and 2.1 g. oftriethoxyphosphorus (P(OEt)3) were placed in the ball mill pot described in Example 1 and ball-milled for 3 hours at room temperature in a nitrogen atmosphere, then 4.5 g. of tetraisopropoxysilane and 3.0 g. of titanium tetrachloride were added, followed by further ball milling for 16 hours, to obtain a solid catalyst component [I] containing 37 mg. of titanium per gram thereof.

A continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same way as in Example 1 except that the solid catalyst component [I] just prepared above was fed at a rate of 50 mg/hr and monophenyltriethyoxysilane was fed at a rate of 0.25 mmol/hr in place of the monomethyltriethoxysilane, to afford an ethylene copolymer having a bulk density of 0.35, a density of 0.9218 and a melt index of 1.1.

Catalytic activity was 270,000g.copolymer/g.Ti and thus very high.

After the continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

The F.R. value of this copolymer was 7.0, and when a film formed from the copolymer was extracted in boiling hexane, its hexane extraction was 0.9 wt.% and thus very small.

Example 5 10 g. of an anhydrous magnesium chloride, 3.5 g. of diethoxyzinc and 2.8 g. of diisopropoxydichlorotitanium were placed in the ball mill pot described in Example land ball-milled for 16 hours at room temperature in a nitrogen atmosphere, then 3.8 g. of triethoxymonochlorosilane was added, followed by further ball milling for 7 hours to obtain a solid catalyst component [I] containing 28 mg. of titanium per gram thereof.

A continuous vapor phase polymerization was carried out in the same way as in Example 1 except that the solid catalyst component [I] just prepared above was fed at a rate of 50 mg/hr and tetraethoxysilane was fed at a rate of 0.25 mmol/hr in place of the monomethylethoxysilane, to afford an ethylene copolymer having a bulk density of 0.39, a density of 0.9224 and a melt index of 1.2. Catalytic activity was 330,000g. copolymer/g.

Ti and thus very high.

After the continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

The F.R. value of this copolymer was 7.0, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction was 0.7 wt.% and thus very small.

Example 6 A stainless steel 2 liter autoclave equipped with an induction stirrer was purged with nitrogen and charged with 1,000 ml. of hexane, then 1 mmol of triethylaluminum, 0.1 mmol of tetraethoxysilane and 10 mg. of the solid catalyst component [I] obtained in Example 1 were added and the temperature was raised to 85"C with stirring. The pressure of the system was adjusted to 2 kg/cm2.G by introducing nitrogen, then hydrogen was introduced up to a total pressure of 5 kg/cm2.G and then ethylene introduced up to a total pressure of 10 kg/cm2.G, under which condition a polymerization was started, which was continued for 1 hour while maintaining the internal pressure of the autoclave at 10 kg/cm2.G.Thereafter, the polymer slurry was transferred into a beaker and hexane was removed under reduced pressure to yield 116 g. of a white polyethylene having a melt index of 1.0, a density of 0.9631 and a bulk density of 0.38. Catalytic activity was 66,300g.polyethylene/g .Ti. hr-C2H4 pressure, 2,320g.polyethyl ene/g.solid.hT'C2H4 pressure.

The F.R. value of the polyethylene was 7.5 and the molecular weight distribution thereof was very narrow as compared with that in Comparative Example 2. Its hexane extraction was 0.2 wt.%.

Comparative Example 2 Polymerization was carried out for 1 hour in the same way as in Example 6 except that the tetraethoxysilane was not added, to yield 134 g. of a white polyethylene having a melt index of 1.4, a density of 0.9637 and a bulk density of 0.35. Catalytic activity was 76,500g.polyethylene/g.Ti.hr-C2H4 pressure, 2,680g.polyethylene/g.solid.hr.C2H4 pressure.

The F.R. value of the polyethylene was 8.3 and its hexane extraction was 0.6 wt.%.

Example 7 The solid catalyst component [I] obtained in Example 1 was fed at a rate of 50 mg/hr and a product obtained by reacting triethylaluminum and monomethyltriethoxysilane at a composition ratio of 5: 0.22 (molar ratio) for 2 hours at room temperature was fed at a rate of 5 mmol/hr as aluminum, under which condition a continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same manner as in Example 1 to afford an ethylene copolymer having a bulk density of 0.34, a density of 0.9214 and a melt index of 0.93. Catalytic activity was 301,000g.copolymer/g.Ti and thus very high.

After the continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

The F.R. value of this copolymer was 6.8, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction was 0.6 wt.% and thus very small.

Example 8 10 g. of a commercially available anhydrous magnesium chloride and 4.2 g. of aluminum triethoxide were placed in a stainless steel pot having a content volume of 400 ml. and containing 25 stainless steel balls each inch (12.7 mm) in diameter, and ball-milled for 16 hours at room temperature in a nitrogen atmosphern to obtain a reaction product.Then, a three-necked flask equipped with a stirrer and a reflux condenser was purged with nitrogen and then charged with 2.5 g. of the above reaction product and 5 g. of SiO2 (&num;952, a product of Fuji-Davison) which had been calcined at 600"C, then 100 ml. of tetrahydrofuran was added and reaction was allowed to take place at 60"C for 2 hours, followed by drying at 120"C under reduced pressure to remove tetrahydrofuran. Then, 50 ml. of hexane was added, and after stirring, 1.1 ml. of titaniuni tetrachloride was added and reaction was allowed to take place for 2 hours under reflux of hexane to obtain a solid powder (A) containing 37 mg. of titanium per gram thereof.

The solid powder (A) thus obtained was added into 50 ml. of hexane, then 2 ml. of tetraethoxysilane was added and reaction was allowed to take place for 2 hours under reflux of hexane to obtain a solid catalyst component.

A continuous vapor phase polymerization was carried out in the same way as in Example 1 except that the solid catalyst component just prepared above was fed at a rate of 150 mg/hr and a product obtained by reacting triethylaluminum and tetraethoxysilane at an Al/Si molar ratio of 20/1 for 1.5 hours at 85 C was fed at a rate of 5 mmol/hr as aluminum, to afford an ethylene copolymer having a bulk density of 0.38, a density of 0.9213 and a melt index of 0.9. Catalytic activity was 543,000g.copolymer/g.Ti and thus very high.

After the continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

The F.R. value of this copolymer was 6.9, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction was 0.8 wt.% and thus very small.

Example 9 10 g. of an anhydrous magnesium chloride and 4.2 g. of diethoxymagnesium were placed in the ball mill pot described in Example 8, and ball-milled for 16 hours at room temperature in a nitrogen atmosphere to obtain a reaction product. Then, 2.5 g. of the reaction product and 5 g. of SiO2 which had been calcined at 600 Cwere put in the three-necked flask described in Example 8, then 100 ml. of tetrahydrofuran was added and reaction was allowed to take place at 60 C for 2 hours, followed by drying at 120"C under reduced pressure to remove tetrahydrofuran.Then, 50 ml. of hexane was added, and after stirring, 1.1 ml. of titanium tetrachloride was added and reaction was allowed to take place for 2 hours under reflux of hexane to obtain a solid powder (B) containing 36 mg. of titanium per gram thereof.

The solid powder (B) thus obtained was added into 50 ml. of hexane, then 2 ml. of tetraethoxysilane was added and reaction was allowed to take place for 2 hours under reflux of hexane to obtain a solid catalyst component.

A continuous vapor phase polymerization was carried out in the same manner as in Example 8 except that the solid catalyst component just prepared above was fed at a rate of 150 mg/hr, to afford an ethylene copolymer having a bulk density of 0.41, a density of 0.9203 and a melt index of 0.8. Catalytic activity was 497,000g.copolymer/g.Ti and thus very high.

After the continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the inner wall and the stirrer were clean with no polymer adhered thereto.

The F.R. value of this copolymer was 6.9, and when a film formed therefrom was extracted in boiling hexane for 10 hours, its hexane extraction was 1.0 wt.% and thus very small.

Claims (12)

1. A process for preparing a polyolefin, which process comprises polymerizing at least one olefin by using a catalyst, said catalyst having been obtained from the following components [I], [II] and [Ill]: [I] a solid substance obtained by the reaction of the following (i) through (iv):: (i) a magnesium halide, (ii) a compound represented by the general formula Me(OR),X,-, wherein Me is an element selected from Groups I through VIII of the Periodic Table, provided silicon, titanium and vanadium are excluded, R is a hydrocarbon radical having 1 to 24 carbon atoms, X is a halogen atom, z is the valence of Me and n isO < n ' z, (iii) a compound represented by the formula R'mSI(OR")nX4-mn wherein R' and R" are each a hydrocarbon radical having 1 to 24 carbon atoms, X is a halogen atom, m and n are 0 = m < 4 and 0 < n = 4, provided 0 < m + n = 4, and (iv) a titanium compound and/or a vanadium compound;; [li] a compound represented by the general formula

wherein R1, R2 and R3 are each a hydrocarbpn radical having 1 to 24 carbon atoms, alkoxy, hydrogen or halogen, R4 is a hydrocarbon radical having 1 to 24 carbon atoms and q is 1 = q = 30; and [III] an organometallic compound.

2. The process of claim 1 wherein said catalyst comprises the combination of a reaction product and the component [I], said reaction product having been obtained by the reaction of the components [II] and [III].

3. The process of claim 1 or claim 2 wherein said Me is magnesium, aluminum, or boron.

4. The process of claim 1, claim 2 or claim 3 wherein the mixing ratio of said magnesium halide to said compound of the general formula Me(OR)nXz~n is in the range of 1/0.001 to 1/20 in terms of Mg/Me molar ratio.

5. The process of any one of claims 1 to 4 wherein the mixing ratio of said magnesium halide to said compound of the general formula R'mSi(OR")nX4~m~n is in the range of 1/0.01 to 1/1 in terms of Mg/Si molar ratio.

6. The process of any one of claims 1 to 5 wherein said compound of the general formula

is used in an amount ranging from 0.1 to 100 moles per mole of said titanium compound and/or said vanadium compound in the component [I].

7. The process of any one of claims 1 to 6 wherein said compound of the general formula

is used in an amount ranging from 1/500 to 1/1 in terms of its molar ratio to said organometallic compound.

8. The process of any one of claims 1 to 7 wherein said olefin is an a-olefin having 2 to 12 carbon atoms.

9. The process of any one of claims 1 to 8 wherein the polymerization reaction is carried out at a temperature ranging from 20 to 1 20"C and at a pressure ranging from atmospheric pressure to 70 kg/cm2.

10. A process as claimed in claim 1, substantially as hereinbefore described with particular reference to the Examples.

11. A process as claimed in claim 1, substantially as illustrated in any one of the Examples.

12. A polyolefin when prepared by the process claimed in any one of the preceding claims.