GB2108514A - Process for preparing polyolefins - Google Patents

Abstract

Olefin polymers are obtained in high yield and high bulk density and at a high polymerization activity when olefins are polymerized in the presence of a catalyst which comprises the combination of: [I] a solid substance obtained by the reaction of at least the following two components: (i) a magnesium compound represented by the general formula R<1>m(OR<2>)nMgX2-m-n wherein R<1> and R<2> are each a hydrocarbon radical having 1 to 24 carbon atoms, X is a halogen atom, m is 0</=m</=2 and n is 0</=n</=2, provided that 0</=m+n</=2, and (ii) a titanium compound and/or a vanadium compound; [II] a silicon compound represented by the general formula <IMAGE> wherein R<3>, R<4> and R<5> are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen, or halogen, R<6> 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 The present invention relates to a process for preparing polyolefins using a novel polymerization catalyst.

Heretofore, in the technical field of this sort there has been known from Japanese Patent Publication No. 12105/1964 a catalyst comprising a magnesium halide and a transition metal compound such as titanium compound supported thereon. Also, a catalyst obtained by the co-pulverization of a magnesium halide and titanium tetrachloride is known from Belgian Patent No. 742,112.

However, when viewed from the standpoint that the catalyst activity is desired to be as high as possible in the manufacture of polyolefins, the process disclosed in the Japanese Patent Publication No. 12105/1964 is still unsatisfactory because of a low polymerization activity, while the polymerization activity attained in the process of the Belgian Patent No. 742,112 is fairly high, but a further improvement is desired.

In the process disclosed in German Patent No. 2137872, the amount of a magnesium halide is used is substantially decreased by the co-pulverization of thereof with titanium tetrachloride and alumina, but a remarkable increase in activity per solid, which can be regarded as a guideline for productivity, is not recognized and it is desired to develop a catalyst of a higher activity.

In the manufacture of polyolefins, moreover, it is also desirable from the aspects of productivity and handling that the bulk density of the resulting polymer be as high as possible. From this standpoint, the process disclosed in the Japanese Patent Publication No. 12105/1964 is not satisfactory in both the bulk density of the resulting polymer and polymerization activity, while in the process disclosed in the Belgian Patent No. 742,112, the polymerization activity is high, but the bulk density of the resulting polymer is low.

Thus, in both the processes, a further improvement is desired.

SUMMARY OF THE INVENTION According to the present invention there are provided a novel polymerization catalyst and a process for polymerizing olefins using the catalyst, capable of remedying the above-mentioned drawbacks, attaining a high polymerization activity, affording polymers with a high bulk density in high yield and practising a continuous polymerization extremely easily.

The aforesaid objects of the present invention can be attained by polymerizing at least one olefin in the presence of a catalyst system, which catalyst system comprises the combination of: [lj a solid substance obtained by the reaction of at least the following two components:: (i) at least one magnesium compound represented by the general formula R'm(OR2)nMgX2~m~n wherein R' and R2 are each a hydrocarbon radical having 1 to 24 carbon atoms, X is a halogen atom, m is O~m'2 and n is O'n < 2, provided Ohm + n < 2, and (ii) a titanium compound and/or a vanadium compound; [II] a silicon compound represented by the general formula

wherein R3, R4 and R5 are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen, or halogen, R6 is a hydrocarbon radical having 1 to 24 carbon atoms and q is 1=q=30; and [III] an organometallic compound.

The foregoing objects of the present invention can be attained also by polymerizing at least one olefin in the presence of a catalyst which comprises the combination of: [13 a solid substance obtained by the reaction of: (i) a magnesium halide, (ii) at least one compound represented by the general formula Me(OR)nXz~n wherein Me is an element of Groups l-VIII in the Periodic Table, with the limitation that 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 is O < n=z, and (iii) a titanium compound and/or a vanadium compound;; [III] a silicon compound represented by the general formula

wherein R3, R4, R5, P6 and q are as defined above; and [III] an organometallic compound.

Since the polymerization catalyst of the present invention exhibits a very high polymerization activity, the partial pressure of monomer during polymerization is low, and because of a high bulk density of the resulting polymer, the prductivity can be improved. Moreover, the amount of the catalyst remaining in the resulting polymer after polymerization is so small that the polyolefin manufacturing process can dispense with the catalyst removing step, which leads to simplification of the polymer treating step, and consequently polyolefins can be prepared very economically.

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

The present invention is further advantageous in that when viewed from the standpoint of particle size of the resulting polymer, the proportion of coarse particles and that of fine particles below 50y are small despite of a high bulk density of the polymer, and that therefore not only it becomes easy to perform a continuous polymerization reaction but also the centrifugal separation in the polymer treating step as well as the handling of polymer particles in powder transport become easy.

According to the present invention, in addition to the high bulk density of polyolefins obtained by using the catalyst of the invention as previously noted, polyolefins having a desired melt index can be prepared at a lower hydrogen concentration than in conventional methods, thus permitting polymerization to be carried out at a relatively small total pressure, and this greatly contributes to the improvement of economy and productivity.

Additionally, in the olefin polymerization using the catalyst of the present invention, the olefin absorbing rate does not decrease so much even with the lapse of time, and therefore the polymerization can be conducted for a long time in a small amount of the catalyst.

Furthermore, polymers prepared by using the catalyst of the present invention have a very narrow molecular weight distribution and their hexane extraction is very small, reflecting minimized by-production of low grade polymers. Therefore, for example, in the film grade, those polymers can afford products of good quality such as a superior anti-blocking property.

The catalyst of the present invention is a novel catalyst having these many characteristic features and remedying the foregoing drawbacks associated with the prior art. It is quite surprising that these features can be attained and the drawbacks remedied by using the catalyst of the present invention.

DETAILED DESCRIPTION OF THE PRE FERRED EMBODIMENT Examples of the compound of the general formula R'm(OR2)nMgX2~m~n used in the present invention include magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, diethylmagnesium,diisopropylmagnesium, di-n-butylmagnesium, disec-butylmagnesium, methyl magnesium chloride, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, n-propylmagnesium chloride, n-butylmagnesium chloride, n-butylmagnesium bromide, sec-butylmagnesium chloride, phenylmagnesium chloride, decylmagnesium chloride, methoxymagnesium chloride, ethoxymagnesium chloride, isopropoxymagnesium chloride, n-butox ymagnesium chloride, n-octoxymagnesium chloride, methylmagnesium methoxide, ethylmagnesium methoxide, n-butylmagnesium ethoxide, sec-butylmagnesium ethoxide, decylmagnesium ethoxide, diethoxymagnesium, diisopropoxymagnesium, di-n-butoxymagnesium, di-sec-butoxymagnesium, di-t-butoxymagnesium, and di-n-octoxymagnesium. These compounds may also be used as a complex with trialkylaluminium, such as a complex of di-nbutylmagnesium and triethylaluminium. Magnesium halides, particularly substantially anhydrous magnesium halides, are preferred.

It is preferably that the above-exemplified magnesium compounds be used together with the compound of the general formula Me(OR)nX2~n wherein Me is an element of Groups l-VIII in the Periodic Table, with the limitation that 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 is O < nz.

Examples of the compound of the general formula Me(OR)nXz~n used in the present invention include various compounds, such 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, P(OR)5, Cr(OR)2, Mn(OR)2, Fe(OR)2, Fe(OR)3, Co(OR)2, and Ni(OR)2.As concrete preferred examples, there may be mentioned the following compounds: NaOC2H6, NaOC4Hg, Mg(OCH3)2, Mg(OC2H2, Mg(OC6H5)2, Ca(OC2H5)2, Zn(OC2H5)2, Zn(OC2H5)CI, Al(OCH3)3, Al(OC2H5)3, Al(OC2H5)2CI, Al (OC3H7)3, Al(OC4H9)3, Al(OC6H5)3, B(OC2H5)3, B(OC2H5)2CI, P(OC2H5)3, P(OC6H5)3, Fe(OC4Hg)3. Particularly, compounds represented by the general formulae Mg(OR)nX2~n, Al(OR)nX3n and B(OR)nX3~n are preferred. As the substituent R, alkyl groups having 1 to 4 carbon atoms and phenyl are preferred.

Examples of the titanium compound and/or vanadium compound used in the present invention include halides, alkoxyhalides, alkoxided and halogenated oxides, of titanium and/or vanadium. As preferred examples of the titanium compound, there may be mentioned tetravlent and trivalent compounds. As tetravalent titanium compounds, those represented by the general formula Ti(OR)rX4~r are preferred wherein R is a hydrocarbon radical such as an alkyl, aryl or aralkyl group having 1 to 24 carbon atoms, X is a halogen atom and r is OrS4, such as titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monomethoxytrichlorotitanium, dimethoxydichlorotitanium, trimethoxymonochlorotitan- ium, tetramethoxytitanium, monoethoxytri chlorotitanium, diethoxydichlorotitanium, tri ethoxymonochlorotitaniu m, tetraethoxytitanium, monoisopropoxytrichlorotitanium, diiso propoxydichlorotitanium, triisopropoxymono chlorotitanium, tetraisopropoxytitanium, monobutoxytrichlorotiatanium, bibutoxydichlorotitanium, monopentoxytrichlorotitanium, monophenoxytrichlorotitanium, diphenoxydichlorotitanium, triphenoxymonochlorotitanium and tertraphenoxytitanium.As trivalent titanium compounds, there may be used, for example, titanium trihalides obtained by reducing titanium tetrahalides such as titanium tetrachloride and titanium tetrabromide with hydrogen, aluminum, titanium or an organometallic compound of a Group I-Ill metal in the Periodic Table, as well as trivalent titanium compounds obtained by reducing tetravalent alkoxytitanium halides represented by the general formula Ti(OR)sX4~s with an organometallic compound of a Group I-Ill metal in the Periodic Table, as well as trivalent titanium compounds obtained by reducing tetravalent alkoxytitanium halides represented by the general formula Ti(OR)sX4~s with an organometallic compound of a Group I-I II metal in the Periodic Table, in which formula R is a hydrocarbon radical such as an alkyl, aryl or aralkyl group having 1 to 24 carbon atoms, X is a halogen atom and s is O < s < 4. Examples of the vanadium compound include tetravalent vanadium compounds such as vanadium tetrachloride, vanadium tetrabromide, vanadium tetraiodide and tetraethoxyvanadium, pentavalent vanadium compounds such as vanadium oxytrichloride, ethoxydichlorovanadyl, triethoxyvanadyl and tributoxyvanadyl and tributoxyvanadyl, and trivalent vanadium compounds such as vanadium trichloride and vanadium triethoxide. Tetravalent titanium compounds are most preferable in the present invention.

To make the present invention more effective, the titanium compound and the vanadium compound are often use together. In this case, it is preferable that the V/Ti mole ratio be in the range of 2/1 to 0.01/1.

The method of obtaining the catalyst component [I] in the invention by reacting a compound of the general formula R'm(OR2)nMgX2~m~n with a titanium compound and/or vanadium compound is not specially limited. Both may be reacted by contacting usually for 5 minutes to 20 hours under heating at a temperature of 20 to 400"C, preferably 50 to 300"C in the presence or absence of an inert solvent. Alternatively, the reaction may be carried out by copulverization treatment.

In the case of obtaining the catalyst component [13 by the reaction of a magnesium halide, a compound of the general formula Me(OR)nXz~n and a titanium compound and/or a vanadium compound, its method is not specially limited, either. These compounds may be reacted by contacting usually for 5 minutes to 20 hours under heating at a temperature of 20 to 400"C, preferably 50 to 300"C, in the presence or absence of an inert solvent, or may be reacted by co-pulverization treatment, or by a suitable combination of these methods. In this case, the order of reaction of the three components is not specially limited.All of them may be reacted together, or first two of them may be reacted followed by further reaction with the remaining one component.

The inert solvent which may be used in preparing the catalyst component [I] is not speciaaly limited. Hydrocarbons and/or derivatives thereof not inactivating Ziegler type catalysts are usually employable, for example, various saturated aliphatic hydrocarbons, aromaic 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.

The apparatus to be used for the co-pulverization is not specially limited. Usually, a ball mill, a vibration mill, a rod mill or an impact mill is used. Conditions for the co-pulverization such as temperature and time can be decided easily by those skilled in the art according to the co-pulverization method used. In general, the co-pulverization is carried out at a temperature ranging from 0 to 200"C, preferably 20 to 100"C, for a period of time ranging from 0.5 to 50 hours, preferably 1 to 30 hours. Of course, the co-pulverizing operation should be performed in an inert gas atmosphere, and moisture should be avoided.

In the preparation of the catalyst component [I], in case the magnesium halide and the compound of the general formula Me(OR)nXz~n are used together, the polymerization activity tends to lower in both the cases of too small and too large amounts of the compound of the general formula Me(OR)nXz~n. Their mixing ratio in the range of 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 mole ratio, is desirable for the manufacture of a high activity catalyst.

The amount of the titanium compound and/or vanadium compound used in the preparation of the catalyst component [13 is, most preferably, adjusted so that it is within the range of 0.5 to 20% by weight in terms of titanium and/or vanadium contained in the catalyst component [I]. The range of 1 to 10% by weight is particularly preferred in order to attain a well-balanced activity per titanium and/or vanadium and that per solid.

In preparing the catalyst component [I] in the present invention, moreover, a component (vex) being a member or members selected from the group consisting of organic halides, halo genating agents, phosphoric esters, electron donors and polycyclic aromatic compounds may also preferably be used at the same time.

The component (vex) may be used in an amount of 0.01 to 5 moles, preferably 0.05 to 2 moles, per mole of the magnesium compound.

The organic halides which may be used as component (a) are partially halogen-substituted, saturated or unsaturated aliphatic and aromatic hydrocarbons, including mono-, diand tri-substituted compounds. The halogen may be any of fluorine, chlorine, bromine and iodine.

Examples of such organic halides include methylene chloride, chloroform, carbon tetrachloride, bromochloromethane, dichlorodifluoromethane, 1 -bromo-2-chloroethane, chloroethane, 1.2-dibromo-l,l -dichloroethane. 1,1dichloroethane, 1,2-dichloroethane, 1,2-di- chloro-1,1,2,2-tetrafluoroethane, hexachloroethane, pentachloroethane, 1,1,1,2-tetrachloro- ethane, 1,1 ,2,2-tetrachloroethane, 1,1,1 -tri- chloroethane, 1,1 ,2-trichloroethane, 1 - hloro- propane, 2-chloropropane, 1,2-dichloropropane, 1, 3-dichloropropane, 2,2-dichloropropane, 1,1,1 ,2,2,3,3-heptachloropropane, 1,1,2,2,3, 3-hexachloropropane, octachloropropane, 1,1 ,2-trichloropropane, 1-chlorobu- tane, 2-chlorobutane, 1 -chloro-2-methylpro- pane, 2-chloro-2-methylpropane, 1,2-dichlorobutane, 1,3-dichlorobutane, 1 ,4-dichlorobu- tane, 2,2-dichlorobutane, 1-chloropentane, 1chlorohexane, 1 -chloroheptane, 1-chlorooc- tane, 1-chlorononane, 1-chlorodecane, vinyl chloride, 1 , 1 -dichloroethylene, 1,2-dichloroethylene, tetrachloroethylene, 3-chloro-1 -pro- pene, 1 ,3-dichloropropene, chloroprene, oleyl chloride, chlorobenzene, chloronaphthalene, benzyl chloride, benzylidene chloride, chloroethylbenzene, styrene dichloride, and a-chloro- cumene.

Examples of halogenating agents which may be used in the invention include halides of nonmetals such as sulfur chloride, PAL3, PCl5 and SiCI4, as well as oxyhalides of nonmetals such as POCI3, COCI2, NOCI2, SOCI2 and SO2Cl2.

Examples of electron donors which may be used in the invention include alcohols, esters, ketones, aldehydes, organic acids, organic acid esters, acid halides, acid amides, amines and nitriles.

As alcohols there may be used, for example, those having 1 to 1 8 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, allyl alcohol, n-buty alcohol, isobutyl alcohol, sec-buty alcohol, tbutyl alcohol, n-amyl alcohol, n-hexyl alcohol,.

cyclohexyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, benzyl alcohol, naphthyl alcohol, phenol, and cresol.

As esters there may be used, for example, those having 2 to 20 carbon atoms, such as dimethyl ether, diethyl ether, diethyl ether, dibutyl ether, isomyl ether, anisole, pheneole, diphenyl ether, phenylallyl ether, and benzofuran.

As ketones there may be used, for example, those having 3 to 1 8 carbon atoms such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl phenyl ketone, ethyl phenyl ketone, and diphenyl ketone.

As aldehydes there may be used, for example, those having 2 to 1 5 carbon atoms such as acetyldehyde, propionaldehyde, octylaldehyde, benzaldehyde, and naphthaldehyde.

As organic acids there may be used, for example, those having 1 to 24 carbon atoms such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, pivalic acid, caproic acid, caprylic acid, stearic acid, oxalic acid, malonic acid, succinic acid, adipic acid, methacrylic acid, benzoic acid, toluic acid, anisic acid, oleic acid, linoleic acid, and linolenic acid.

As organic acid esters there may be used, for example, those having 2 to 30 carbon atoms such as methyl formate, methyl acetate, ethyl acetate, propyl acetate, octyl acetate, ethyl propionate, methyl butyrate, ethyl valerate, methyl methacrylate, methyl benzoate, ethyl benzoate, propyl benzoate, octyl benzoate, phenyl benzoate, benzyl benzoate, ethyl o-methoxybenzoate, ethyl p-ethoxybenzoate, butyl p-ethoxybenzoate, methyl p-toluylate, ethyl p-toluylate, ethyl p-ethylbenzoate, methyl salicylate, phenyl salicylate, methyl naphthoate, ethyl naphthoate, and ethyl anisate.

As acid halides there may be used, for example, those having 2 to 1 5 carbon atoms such as acetyl chloride, benzyl chloride, toluic acid chloride, and anisic acid chloride.

As acid am ides there may be used, for example, acetic amide, benzoic acid amide and toluic acid amide.

As amines there may be used, for example, methylamine, ethylamine, diethylamine, tributylamine, piperidine, tribenzylamine, aniline, pyridine, picoline, and terramethylenediamine.

As nitriles there may be used, for example, acetonitrile, benzonitrile and tolunitrile.

Phosphoric esters which may be used in the present invention are compounds represented by the general formula

wherein R, which may be alike or different, is a hydrocarbon radical having 1 to 24 carbon atoms. Examples of such compounds include triethyl phosphate, tri-n-buty phosphate, triphenyl phosphate, tribenzyl phosphate, trioctyl phosphate, tricresyl phosphate, tritolyl phosphate, trixylyl phosphate, and diphenylxy lenyl phosphate.

Examples of polycyclic aromatic compounds which may be used in the present invention include naphthalene, phenanthrene, triphenylene, chrysene, 3,4-benzophenanthrene, 1,2benzochrysene, picene, anthracene, tetraphene, 1 2, 3,4-dibenzanthracene, pentaphene, 3,4-benzopentaphene, tethracene, 1 ,2-benzotethracene, hexaphene, heptaphene, diphenyl, fluorine, biphenylene, perylene, coronene, bisantene, ovalene, pyrene, and perinaphthalene, as well as halogenated alkylsubstituted derivatives thereof.

The catalyst component [I] thus obtained may be supported on an oxide of a Group Il-IV metal in the Periodic Table. This is also preferable in the present invention. In this case, not only oxides of Group Il-IV metals each alone but also double oxides these metals, as well as mixtures thereof, are employable. Examples of such metal oxides include MgO, CaO, ZnO, BaO, SiO2, SnO2, Al203, MgO Ai203, SiO2 AI203, MgO SiO2, MgOCaOAI2O2, and Al2O2CaO.

The method of supporting the catalyst component [I] on an oxide of a Group Il-IV met 1 in the Periodic Table is not specially limited, but as a preferred example there may be mentioned a method wherein the components (i) and (ii) and if required the component (a) are fed in the presence of such metal oxide and an ether compound as solvent and allowed to react under heating, then the liquid phase portion is removed.

Examples of the silicon compound of the general formula

used in the present invention include monomethyl trimethoxy silane, monomethyl triethoxy silane, monomethyl tri-n-butoxy silane, monomethyl tri-sec-butoxy silane, monomethyl triisopropoxy silane, monomethyl tripentoxy silane, monomethyl trioctoxy silane, monome thyl tristearoxy silane, monomethyl triphenoxy silane, dimethyl dimethoxy silane, dimethyl diethoxy silane, dimethyl diisopropoxy silane, dimethyl diphenoxy silane, trimethyl monomethoxy silane, trimethyl monoethoxy silane, trimethyl monoisopropoxy silane, trimethyl monophenoxy silane, monomethyl dimethoxy monochlorosilane, monomethyl diethoxy monochlorosilane, monomethyl diethoxy monochlorosilane, monomethyl diethoxy monobromosilane, monomethyl diphenoxy monochlorosilane, dimethyl monoethoxy monochlorosilane, monoethyl trimethoxy silane, monoethyl triethoxy silane, monoethyl triisopropoxy si- lane, monoethyl triphenoxy silane, diethyl di methoxy silane, diethyl diethoxy silane, di ethyl diphenoxy silane, triethyl monoethoxy silane, triethyl monoethoxy silane, triethyl mo nophemoxy silane, monoethyl dimethoxy mo nochlorosilane, monoethyl diethoxy monochlo rosilane, monoethyl diphenoxy monochlorosi lane, monoisopropyl trimethoxy silane, mono n-butyl trimethoxy silane, mono-n-butyl tri ethoxy silane, mono-sec-butyl triethoxy silane, monophenyl triethoxy silane, diphenyl di ethoxy silane, diphenyl monoethoxy mono chlorosilane, monomethoxy trichlorosilane, monoethoxy trichlorosilane, mono-n-butoxy tri chlorosilane, monopentoxy trichlorosilane, mo nooctoxy trichlorosilane, monostearoxy trichlo rosilane, monophenoxy trichlorosilane, mono p-methyl phenoxy trichlorosilane, dimethoxy dichlorosilane, diethoxy dichlorosilane, diiso propoxy dichlorosilane, di-n-butoxy dichlorosi lane, dioctoxy dichlorosilane, trimethoxy mo nochlorosilane, triethoxy monochlorosilane, tri isopropoxy monochlorosilane, tri-n-butoxy mo nochlorosilane, tri-sec-butoxy monochlorosi lane, tetraethoxy silane, tetraisopropoxy si- lane, as well as chain or cyclic polysiloxanes having a recurring unit represented by the formula

obtained by condensation of the compounds exemplified above. Particularly, silicon compounds of the foregoing general formula wherein q = 1 are preferred. More preferable silicon compounds are those 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, X is a halogen atom, m is O~m < 4 and n is O < nS4, provided O < m + n'4.

If the amount of the compound of the general formula

used in the present invention is too large or too small, its effect of addition cannot be expected. Usually, its amount ranges from 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].

As examples of the organometallic compound used in the present invention, there may be mentioned organometallic compounds of Group l-IV metals in the Periodic Table known as a component of Ziegler type catalysts, but organoalumin compounds and organozinz compounds are particularly preferred, for example, organoaluminium compounds of the general formula R3AI, R2AIX, RAIX2, R2A lOR, RAI(OR)X and R3AI2X3 wherein R, which may be alike or different, is an alkyl or aryl group having 1 to 20 carbon atoms and X is a halogen atom, and organozinc compounds of the general formula R2Zn wherein R, which may be alike or different, is an alkyl group having 1 to 20 carbon atoms, such as triethylaluminium triisopropylaluminium, triisobutylaluminium, tri-sec-butylaluminium, tri-tert-butylaluminium, trihexylaluluminium, trioctylaluminium, diethylaluminiumchloride, diisopropyla luminiumchloride, ethylaluminiumsesquichloride, diethylzinc, and mixtures thereof. Together with these organometallic compounds there may be used organocarboxylic acid esters such as ethyl benzoate, ethyl o- or ptoluylate and ethyl p-anisate. The amount of the organometallic compound is not specially limited, but usually it ranges from 0.1 to 1,000 moles per mole of the titanium compound and/or vanadium compound.

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

may be reacted with the organometallic compound in advance and the reaction product is combined with the solid substance [I]. In this case, the reaction ratio is such that the molar ratio of the silicon compound to the organometallic compound is in the range of 1:500 to 1:1, preferably 1:100 to 1:2. The amount of the reaction product to be used is preferably in the range of 0.1:1 to 100:1 and more preferably 0.3:1 to 20:1 in terms of Si:Ti and/or V mole ratio with respect to the titanium compound and/or vanadium compound in the catalyst component [13.

The olefin polymerization using the catalyst of the present invention may be carried out by slurry polymerization, solution polymerization or vapor phase polymerization. Particularly, vapor phase polymerization is preferred. The polymerization 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 120"C, preferably 50 to 100"C, and pressures ranging from atomospheric pressure to 70 kg/cm2, preferably 2 to 60 kg/cm2. Adjustment of the molecular weight can be made to some extent by changing polymerization conditions such as polymerization temperature and catalyst mole 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, two or more multi-stage polymerization reactions having different polymerization conditions such as different hydrogen concentrations and different polymerization temperatures can be performed without any trouble.

The process of the present invention is applicable to the polymerization of all olefins that are polymerizable with a Ziegler type catalyst. Particularly, a-olefins having 2 to 1 2 carbon atoms are preferred. For example, the process of the present invention is suitable for application to the homopolymerization of such a-olefins as ethylene, propylene, 1-butene, hexene-1, 4-methylpentene-1 and octene-1, the copolymerization of ethylene/propylene, ethylene/ 1 -butene, ethylene/hexane-1, ethylene/4-methylpentene- 1, ethylene/octene- 1 and propylene/1-butene, as well as the copolymerization of ethylene and other two or more a-olefins.

Copolymerization with dienes for the purpose of modification of polyolefins may also be conducted preferably. As dienes there may be used, for example, butadiene, I ,4-hexadi- ene, ethylidene norbornene and dicyclopentadiene.

The following examples are given to further illustrate the present invention, but it is to be understood that the invention is not limited thereto.

Example 1 (a) Preparation of a Solid Catalyst Component [I] 10 g. of a commercially available anhydrous magnesium chloride, 2.3 g. of aluminiumtriethoxide and 2.5 g. of titanium tetrachloride were placed in a stainless steel pot having content volume of 400 ml. and containing 25 stainless steel balls each 1/2 inch in diameter, and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere, to obtain a solid catalyst component [I] containing 41 mg. of titanium per gram thereof.

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

Into the autoclave held at 80"C were fed the solid catalyst component [I] prepared above, monomethyl triethoxy silane and triethylaluminium at the rates of 50 mg/hr, 0.22 mmol/hr and 5 mmol/hr, respectively.

Further, butene-1, ethylene and hydrogen gases were fed while adjusting the butene 1 /ethylene mol ration in the vapor phase in the autoclave to 0.27 and the hydrogen concentration to 15% of the total pressure, and polymerization was allowed to take place while recycling the intra-system gases by the blower to maintain the total pressure at 10 kg/cm2G, to give an ethylene copolymer having a bulk density of 0.33, a melt index (Ml) of 0.9 and a density of 0.9213. The catalyst activity was 318, 8,000g.copolymer/g.Ti.

After a continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, the interior of the autoclave proved to be clean with no polymer adhered to the inner wall and the agitator.

F.R. value (F.R. = Ml10/MI2 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 My2.18 thereof determined at a load of 2.16 kg. both at 190"C according to the method defined by ASTM-D1238-65T, was 7.0, indicating that the molecular weight distribution was very narrow.

When a film formed from this copolymer was extracted in boiling hexane for 10 hours, its hexame extraction proved to be 0.9 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 monomethyl triethoxy silane was not added, to give an ethylene copolymer having a bulk density of 0.33, a density of 0.9203 and a melt index of 1.3. The catalyst activity was 346,00Og.copolymer/g.Ti.

After a continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, a small amount of polymer proved to adhere to the inner wall and the agitator.

The F.R. value of the copolymer was 8.3, and its hexane extraction after 10 hours' extraction in boiling hexane was 4.3 wt.%.

Example 2 10 ml. of ethanol, 20 g. of anhydrous magnesium chloride and 4.6 9. of triethoxyboron were charged into a three-necked 300 cc. flask equipped with a magnetic induction stirrer, and allowed to react for 3 hours under reflux. Thereafter, 1 50 ml. of n-hexane was added to allow precipitation to take place, and after standing, the supernatant liquid was removed, followed by vacuum drying at 200"C to give a white dry powder.

11 g. of the white dry powder prepared above and 2.3 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 in diameter, and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere, to give a solid catalyst component [I] containing 43 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 the rate of 50 mg/hr, to give an ethylene copolymer having a bulk density of 0.35, a density of 0.9218 and a melt index of 1.3. The catalyst activity was 374,000g.copolymer/g.Ti and thus was very high.

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

The F.R. value of the copolymer was 7.1, and when a film formed from the copolymer was extracted for 10 hours in boiling hexane, its hexane extraction proved to be 1.1 wt.% and thus very small.

Example 3 10 g. of anhydrous magnesium chloride, 3.1 g. of diethoxymagnesium and 2.1 g. of titanium tetrachloride were placed in the ball mill pot described in Example 1 and ballmilled for 1 6 hours at room temperature in a nitrogen atmosphere, to give a solid catalyst component [I] containing 35 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 the rate of 50 mg/hr and tetraethoxy silane in place of monomethyl triethoxy silane was fed at the rate of 0.25 mmol/hr, to afford an ethylene copolymer having a bulk density of 0.34, a density of 0.9208 and a melt index of 0.91. The catalyst activity was 427,000g.copolymer/g.Ti and thus was very high.

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

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

Example 4 10 g. of anhydrous magnesium chloride, 2.1 g. of triethoxyphosphorus (P(OEt)3) and 2.1 g. of titanium tetrachloride were placed in the ball mill pot described in Example 1 and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere, to give a solid catalyst component [13 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 the rate of 50 mg/hr and monophenyl triethoxy silane in placed of monomethyl triethoxy silane was fed at the rate af 0.25 mmol/hr, to afford an ethylene copolymer having a bulk density of 0.38, a density of 0.9218 and a melt index of 1.2.

The catalyst activity was 348,000g.copolymer/g.Ti and thus was very high.

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

The F.R. value of the copolymer was 7.2, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.2 wt.% and thus very small.

Example 5 10 g. of anhydrous magnesium chloride, 3.5 g. of diethoxyzinc and 2.0 g. of diisopropoxydichlorotitanium were placed in the ball mill pot described in Example 1 and ballmilled for 1 6 hours at room temperature in a nitrogen atmosphere, to give a solid catalyst component [13 containing 32 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 the rate of 50 mg/hr and terraethoxy silane in place of monomethyl ethoxy silane was fed at the rate of 0.25 mmol/hr, to afford an ethylene copolymer having a bulk density of 0.39, a density of 0.9215 and a melt index of 1.1. The catalyst activity was 378,000g.copolymer/g.Ti and thus was very high.

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

The F.R. value of the copolymer was 7.1, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.3 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 triethylaluminium, 0.05 mmol of tetraethoxy silane and 10 mg. of the solid catalyst component [13 obtained in Example 1 were added, and the temperature was raised to 90"C under stirring. The system was pressurized to 2 kg/cm2.G by the vapor pressure of hexane, then hydrogen was introduced to a total pressure of 4.8 kg/cm2G, and thereafter ethylene was introduced to a total pressure of 10 kg/cm2 G to initiate polymerization.The polymerization was carried out for 1 hour while maintaining the pressure in the autoclave at 10 kg/cm2.G. Thereafter, the polymer slurry was transferred into a beaker and hexane removed under reduced pressure to yield 1 43 g. of a white polyethylene having a melt index of 1.2, a density of 0.9633 and a bulk density of 0.37. The catalyst activity was 67,1 00g.polyethylene/g.Ti.hr.C2H4 pressure, 2,750g.polyethylene/g.solid.hr.C2H4 pressure.

The F.R. value of the polyethylene was 8.0 and thus the molecular weight distribution was very narrow as compared with that in Comparative Example 2, and its hexane extraction proved to be 0.18 wt.%.

Comparative Example 2 Polymerization was carried out for 1 hour in the same way as in Example 6 except that tetraethoxy silane was not added, to yield 149 g. of a white polyethylene having a melt index of 1.6, a density of 0.9637 and a bulk density of 0.32. The catalyst activity was 69,900g.polyethylene/g.Ti hr C2H4 pressure, 2,870g.polyethylene/g.solid.hr.C2H4 pressure.

The F.R. value of the polyethylene was 9.4 and its hexane extraction proved to be 1.3 wt.%.

Example 7 The solid catalyst component [I] obtained in Example 1 was fed at the rate of 50 mg/hr, and a product obtained by the reaction of triethylaluminium and monomethyl triethoxy silane at the composition (mol ratio) of 5:0.22 for 2 hours at room temperature was fed at the rate of 5 mmol/hr in terms of aluminum, under which conditions a continuous vapor phase polymerization of ethylene and butene 1 was carried out following the procedure of Example 1, to afford an ethylene copolymer having a bulk density of 0.32, a density of 0.9211 and a melt index of 0.97. The cata Jyst activity was 328,000g.copolymer/g.Ti and thus was very high.

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

The F.R. value of the copolymer was 7.1, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.2 wt.% and thus very small.

Example 8 (a) Preparation of a Solid Catalyst Component [13 .200 ml. of ethanol, 20 g. of ethoxymagnesium chloride (Mg/CI mol ratio = 0.81) ob taineq by treating magnesium diethoxide with HCl, 'lOg. of triethyl phosphate and 20 g. of tetraethoxy silane was placed in a threenecked 500 cc. flask equipped with an induction stirrer, and allowed to react for 3 hours under reflux of ethanol. Thereafter, the supernatant liquid was removed and the reaction product was washed with three 200 ml. portions of hexane. Then 200 ml. of hexane and 5 ml. of titanium tetrachloride were added and allowed to react for 2 hours under reflux of hexane.Then, after removing the supernatant liquid, the reaction product was washed with hexane five times to obtain a solid catalyst component containing 21 mg. of titanium per gram thereof.

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

Into the autoclave held at 80"C were fed the solid catalyst component [13 prepared above and triethylaluminium at the rates of 50 mg/hr and 5 mmol/hr, respectively. Further, butene-1, ethylene and hydrogen gases were fed while adjusting the butene-1 /ethylene mol ratio in the vapor phase in the autoclave to 0.27 and the hydrogen concentration to 15% of the total pressure, and polymerization was allowed to take place while recycling the intra-system gases by the blower to maintain the total pressure at 10 kg/cm2G, to afford an ethylene copolymer having a bulk density of 0.29, a melt index (MI) of 1.1 and a density of 0.9208. The catalyst activity was 238,000g.copolymer/g. Ti.

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

The F.R. value was 7.3 and thus the molecular weight distribution was very narrow.

When a film formed from this copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.5 wt.% and thus very small.

Comparative Example 3 A solid catalyst component was prepared in the same way as in Example 8 except that tetraethoxy silane was not used. It contained 22 mg. of titanium per gram thereof.

A continuous polymerization of ethylene and butene-1 was carried out in the same manner as in Example 8 except that the solid catalyst component just prepared above was fed at the rate of 50 mg/hr, to afford an ethylene copolymer having a bulk density of 0.23, a density of 0.9203 and a melt index of 1.4. The catalyst activity was 164,000g.copolymer/g.Ti.

The F.R. value of the copolymer was 8.1 and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 4.4 wt.%.

Example 9 200 ml. of hexane, 30 g. of ethoxymagnesium chloride (Mg/CI mol ratio = 0.81) obtained by treating magnesium diethoxide with HCI and 10 g. of t-butyl chloride were placed in a three-necked 500 cc. flask equipped with a stirrer and allowed to react for 2 hours under reflux of hexane, than 10 g. of titanium tetrachloride was added and reaction was further allowed to proceed for 2 hours. Thereafter, the supernatant liquid was removed and the reaction product was washed with three 200 ml. portions of hexane. Then, 200 ml. of hexane and 20 g. of tetraethoxy silane were added and reacted for 2 hours under reflux of hexane. Then, after removing the supernatant liquid, the reaction product was washed with hexane five times to give a solid catalyst component containing 1 8 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 8 except that the solid catalyst component just prepared above was fed at the rate of 50 mg/hr, to afford an ethylene copolymer having a bulk density of 0.34, a density of 0.9211 and a melt index of 1.2. The catalyst activity was 294,000g.copolymer/gTi and thus was very high.

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

The F.R. value of the copolymer was 7.2, and when a film formed from the copolymer was extracted in boiling hexane, its extraction proved to be 1.4 wt.% and thus very small.

Example 10 200 ml. of n-hexane, 20 g. of n-butylmagnesium chloride, 7.5 g. of ethyl benzoate and 20 g. of triethoxy monochlorosilane were placed in a three-necked 500 cc. flask equipped with a stirrer and allowed to react for 3 hours under reflux of hexane. Thereafter, the supernatant liquid was removed and the reaction product was dried up to obtain a white solid substance.

Then, 10 g. of the above solid substance and 1.2 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 in diameter, and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere, to give a solid catalyst component containing 27 mg.

of titanium per gram thereof.

A continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same manner as in Example 8 except that the solid catalyst component just prepared above was fed at the rate of 50 mg/hr, to afford an ethylene copolymer having a bulk density of 0.36, a density of 0.9198 and a melt index of 0.9. The catalyst activity was 239,000g.copolymer/g.Ti and thus was very high.

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

The F.R. value of the copolymer was 7.4, and when a film formed from the copolymer was extracted in boiling hexane, its hexane extraction proved to be 1.6 wt.% and thus very small.

Example 11 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 triethylaluminium and 20 mg. of the solid powder obtained in Example 8 were added, and the temperature was raised to 90"C under stirring. The system was pressurized to 2 kg/cm2 G by the vapor pressure of hexane, then hydrogen was introduced to a total pressure of 4.8 kg/cm2G, and thereafter ethylene was introduced to maintain the total pressure at 10 kg/cm2G, under which condition polymerization was carried out for 1 hour.Thereafter, the polymer slurry was transferred into a beaker and hexane removed under reduced pressure to yield 1 75 9. of a white powder having a melt index of 1.2 and a bulk density of 0.32. The catalyst activity was 80,1 00g.polyethylene/g. Ti hr C2H4 pressure, 1,680g.polyethylene/g. solid hr C2H4 pressure.

The F.R. value of the polyethylene was 8.1, indicating a very narrow molecular weight distribution, and its hexane extraction proved to be 0.17 wt.%.

Example 1 2 (a) Preparation of a Solid Catalyst Component [13 10 g. of a commercially available anhydrous magnesium chloride, 1 g. of 1,2-dichloroethane 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 in diameter, and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere, to obtain a solid catalyst component [I] containing 44 mg. of titanium per gram thereof.

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

Into the autoclave held at 80"C were fed the solid catalyst component [13 prepared above, monomethyl triethoxy silane and triethylaluminium at the rates of 50 mg/kr, 0.22 mmol/hr and 5 mmol/hr, respectively.

Further, butene-1, ethylene and hydrogen gases were fed while adjusting the butene1 /ethylene mol ratio in the vapor phase in the autoclave to 0.27 and the hydrogen concentration to 15% of the total pressure, and polymerization was allowed to take place while recycling the intra-system gases by the blower to maintain the total pressure at 10 kg/cm2G, to give an ethylene copolymer having a bulk density of 0.35, a melt index (Ml) of 1.0 and a density of 0.9211. The catalyst activity was 526,000g.copolymer/g.Ti.

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

The F.R. value was 7.2 and thus the molecular weight distribution was very narrow.

When a film formed from this copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.4 wt.% and thus very small.

Comparative Example 4 A continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same way as in Example 1 2 except that monomethyl triethoxy silane was not added, to afford an ethylene copolymer having a bulk density of 0.31, a density of 0.9195 and a melt index of 1.0. The catalyst activity was 498,000g.copolymer/g.Ti.

After a continuous operation for 10 hours, the autoclave was opened and its interior was checked. As a result, a small amount of polymer proved to adhere to the inner wall and the stirrer.

The F.R. value of the copolymer was 8.9, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 5.3 wt.%.

Example 13 100 ml. of ethanol, 20 g. of anhydrous magnesium chloride and 5 g. of phosphorus oxychloride were charged into a three-necked 300 cc. flask equipped with a magnetic induction stirrer, and allowed to react for 3 hours under reflux. Thereafter, 1 50 ml. of nhexane was added to allow precipitation to take place, and after standing, the supernatant liquid was removed, followed by vacuum drying at 200"C to give a white dry powder.

11 g. of the above white powder and 2.3 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 in diameter, and ballmilled for 1 6 hours at room temperature in a nitrogen atmosphere, to give a solid catalyst component [I] containing 42 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 2 except that the solid catalyst component [I] just prepared above was fed at the rate of 50 mg/hr, to afford an ethylene copolymer having a bulk density of 0.37, a density of 0.9211 and a melt index of 1.3. The catalyst activity was 584,000g.copolymer/g.Ti and thus was very high.

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

The F.R. value of the copolymer was 7.3 and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction to be 1.5 wt.% and thus very small.

Example 1 4 10 g. of anhydrous magnesium chloride, 3.5 g. of anthracene and 2.1 g. of titanium tetrachloride were placed in the ball mill pot described in Example 1 2 and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere, to obtain a solid catalyst component [I] containing 34 mg. of titanium per gram thereof.

A continuous vapor phase polymerization of ethylene and butene-1 was conducted in the same manner as in Example 1 2 except that the solid catalyst component [I] just prepared above was fed at the rate of 50 mg/hr and tetraethoxy silane in place of monomethyl triethoxy silane was fed at the rate of 0.25 mmol/hr, to afford an ethylene copolymer having a bulk density of 0.33, a density of 0.9211 and a melt index of 1.1. The catalyst activity was 481 ,000g.copolymer/g.Ti and thus was very high.

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

The F.R. value of the copolymer was 7.4, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.5 wt.% and thus very small.

Example 1 5 10 g. of an hydros magnesium chloride, 2.5 g. of isoamyl ether and 2.1 g. of titanium tetrachloride were placed in the ball mill pot described in Example 1 2 and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere, to obtain a solid catalyst component [I] containing 36 mg. of titanium per gram thereof.

A continuous vapor phase polymerization of ethylene and butene-1 was conducted in the same manner as in Example 1 2 except that the solid catalyst component [I] just prepared above was fed at the rate of 50 mg/hr and monophenyl triethoxy silane in place of monomethyl triethoxy silane was fed at the rate of 0.25 mmol/hr, to afford an ethylene copolymer having a bulk density of 0.35, a density of 0.9201 and a melt index of 0.91.

The catalyst activity was 354,000g.copolymer/g.Ti and thus very high.

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

The F.R. value of the copolymer was 7.3, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.4 wt.% and thus very small.

Example 16 10 9. of anhydrous magnesium chloride, 3.3 g. of triethyl phosphate and 2.0 g. of diisopropoxydichlorotitanium were placed in the ball mill pot described in Example 1 2 and ball-milled for 1 6 hours at room temperature in a nitrogen atmosphere to obtain a solid catalyst component [I] containing 31 mg. of titanium per gram thereof.

A continuous vapor phase polymerization of ethylene and butene-1 was conducted in the same manner as in Example 1 2 except that the solid catalyst component [I] just prepared above was fed at the rate of 50 mg/hr and tetraethoxy silane in place of monomethyl ethoxy silane was fed at the rate of 0.25 mmol/hr, to afford an ethylene copolymer having a bulk density of 0.37, a density of 0.9207 and a melt index of 1.2. The catalyst activity was 41 8,000g.copolymer/d.Ti and thus very high.

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

The F.R. value of the copolymer was 7.2, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.4 wt.% and thus very small.

Example 1 7 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 triethylaluminium, 0.05 mmol of tetraethoxy silane and 10 mg. of the solid catalyst component [I] obtained in Exam ple 1 2 were added and the temperature was raised to 90"C under stirring. The system was pressurized to 2 kg/cm2G by the vapor pres sure of hexane, then hydrogen was introduced to a total pressure of 4.8 kg/cm2G, and thereafter ethylene was introduced to a total pressure of 10 kg/cm2 G to initiate polymerization.The polymerization was carried out for 1 hour while maintaining the pressure in the autoclave at 10 kg/cm2G. Thereafter, the polymer slurry was transferred into a beaker and hexane removed under reduced pressure to yield 1 46 9. of a white polyethylene having a melt index of 0.9, a density of 0.9629 and a bulk density of 0.35. The catalyst activity was 70,000g.polyethylene/g.Ti hr C2H4 pressure, 2,800g.polyethylene/g.solid.hr.C2H4 pressure.

The F.R. value of the polyethylene was 7.9 and thus the molecular weight distribution was very narrow as compared with Comparative Example 5, and its hexane extraction proved to be 0.35 wt.%.

Comparative Example 5 Polymerization was conducted for 1 hour in the same manner as in Example 1 7 except that tetraethoxy silane was not used, to yield 145 g. of a white polyethylene having a melt index of 1.5, a density of 0.9638 and a bulk density of 0.29. The catalyst activity was 69,800g.polyethylene/g.Ti.hr.C2H4 pressure, 2,790g.polyethylene/g.solid.hr'C2H4 pressure.

The F.R. value of the polyethylene was 9.5 and its hexane extraction proved to be 1.8 wt.%.

Example 18 The solid catalyst component [I] obtained in Example 1 2 was fed at the rate of 50 mg/hr, and a product obtained by the reaction of triethylaluminium and monomethyl triethoxy silane at the composition (mol ratio) of 5:0.22 for 2 hours at room temperature was fed at the rate of 5 mmol/hr in terms of aluminium, under which conditions a continuous vapor phase polymerization was carried out following the procedure of Example 12, to afford an ethylene copolymer having a bulk density of 0.34, a density of 0.9200 and a melt index of 1. 1. The catalyst activity was 473,000g.copolymer/g.Ti and thus very high.

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

The F.R. value of the copolymer was 7.4, and when a film formed from the copolymer was extracted in boiling hexane for 10 hours, its hexane extraction proved to be 1.5 wt.% and thus very small.

Claims (16)

1. A process for preparing a polyolefin, characterized by polymerizing at least one olefin in the presence of a catalyst, said catalyst comprising the combination of: [1] a solid substance obtained by the reaction of at least the following two components: (i) at least one magnesium compound represented by the general formula R'm(OR2)nMgX2~m~n wherein R' and R2 are each a hydrocarbon radical having 1 to 24 carbon atoms, X is a halogen atom, m is 0~m~2 and n is 0'n~2, provided 0m + n5-2, and (ii) a titanium compound and/or a vanadium compound;; [113 a silicon compound represented by the general formula

wherein R3, R4 and R5 are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen, or halogen, R6 is a hydrocarbon radical having 1 to 24 carbon atoms and q is 1=q=30; and [1113 an organometallic compound.

2. The process of claim 1 wherein said magnesium compound is a magnesium halide.

3. The process of claim 1 or claim 2, wherein said solid substance [I] is prepared in the presence of at least one member selected from the group consisting of organic halides, halogenating agents, phosphoric esters, electron donors and polycyclic aromatic compounds.

4. A process for preparing a polyolefin, characterised by polymerizing at least one olefin in the presence of a catalyst, said catalyst comprising the combination of: [I] a solid substance obtained by the reaction of: (i) a magnesium halide, (ii) at least one compound represented by the general formula Me(OR)nXz~n wherein Me is a Group l-VIII element in the Periodic Table, with the limitation that silicon, titanium and vanadium are excluded, R is a hydrocar bonsradical having 1 to 24 carbon atoms, X is a halogen atom, z is the valence of Me and n is Ocn=z, and (iii) a titanium compound and/or a vanadium compound; [II] a silicon compound represented by the general formula

wherein R3, R4, R5, R6 and q are as defined above; and [III] an organometallic compound.

5. The process of claim 2, wherein the reaction ratio of the magnesium halide and the compound represented by the general formula Me(OR),X,~, is in the range of 1/0.001 to 1/20 in terms of Mg/Me ratio.

6. The process of any one of claims 1 to 5, wherein said catalyst comprises the combination of a product obtained by pre-reacting said silicon compound [II] and said organometallic compound [III], with said solid substance [I].

7. The process of any one of claims 1 to 6, wherein said silicon compound is of said general formula wherein q is 1.

8. The process of any one of claims 1 to 7, wherein said solid substance [I] is supported on an oxide of a Group Il-IV metal in the Periodic Table.

9. The process of any one of claims 1 to 8, wherein the titanium and/or vanadium content in said solid substance [I] is in the range of 0.5 to 20 weight percent.

10. The process of any one of claims 1 to 9, wherein the amount of said silicon compound [II] is in the range of 0.1 to 100 moles per mole of the titanium compound and/or the vanadium compound in said solid substance [I].

11. The process of any one of claims 1 to 10, wherein said organometallic compound [III] is an organometallic compound or an organozinc compound.

1 2. The process of any one of claims 1 to 11, wherein said olefin is an a-olefin having 2 to 12 carbon atoms.

1 3. The process of any one of claims 1 to 12, wherein the polymerization reaction is carried out at a temperature in the range of 20 to 120"C and at a pressure in the range of atmospheric pressure to 70 kg/cm2.

14. A process as claimed in claim 1 or claim 4, substantially as hereinbefore described with particular reference to the Examples.

1 5. A process as claimed in claim 1 or claim 4, substantially as illustrated in any one of the Examples.

16. An olefin polymer when prepared by the process claimed in any one of the preceding claims.

1 7. An article fabricated, e.g. by moulding or extrusion, from a polymer as claimed in claim 16.

1 8. An olefin polymerization catalyst as specified in any one of claims 1 to 11.