GB2112402A - Solid transition metal component of ziegler catalyst - Google Patents

Abstract

A solid transition metal component for a Ziegler catalyst comprises a substance obtained by the reaction of at least the following four components: (1) a compound represented by the general formula R<1>m(OR<2>)nMgX2-m-n, (2) a compound represented by the general formula Me(OR<3>)pXz-p, (3) a compound represented by the general formula <IMAGE> and (4) a halogen-containing titanium compound in which formulae R<1>, R<2>, R<3> and R<7> are each a hydrocarbon radical having 1 to 24 carbon atoms, R<4>, R<5> and R<6> are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen or halogen, X is halogen, Me is an element of Groups I-VIII in the Periodic Table provided that silicon and titanium are excluded, z is the valence of Me, and m, n, p and q are as follows: 0</=m</=2, 0</=n<2, 0<m+n</=2, 0<p</=z, 1</=q</=30.

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, a catalyst comprising a magnesium halide and a transition metal compound such as a titanium compound supported thereon has been known from Japanese Patent Publication No. 121 05/1 964, and a catalyst prepared by the co-pulverization of a magnesium halide and titanium tetrachloride has been known from Belgian Patent No. 742,112.

But in the production of polyolefins it is desirable that the catalyst activity be as high as possible, and when viewed from this standpoint, the process disclosed in Japanese Patent Publication No.

12105/1964 affords a still low polymerization activity, and in the process disclosed in Belgian Patent No. 742,112, the polymerization activity is fairly high, but a further improvement is desired.

In German Patent No. 2,137,872, the amount of a magnesium halide used is substantially decreased by its pulverization together 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 a catalyst of higher activity is desired.

In the production of polyolefins, moreover, it is desirable from the aspects of productivity and slurry handling that the bulk density of the resulting polymer be as high as possible. From this standpoint, in the process disclosed in Japanese Patent Publication No. 12105/1964, the bulk density of the resultant polymer is low and the polymerization activity is not in a satisfactory state, and in the process disclosed in Belgian Patent No. 742,112, the bulk density of the resultant polymer is low although the polymerization activity is high, and thus further improvements are desired.

Sunimary of the invention It is the object of the present invention to provide a novel polymerization catalyst capable of remedying the above-mentioned drawbacks, exhibiting a high polymerization activity, affording a polymer of high bulk density in high yield and permitting an extremely easy execution of a continuous polymerization, as well as a process for homopolymerizing or copolymerizing olefins using such polymerization catalyst.

The present invention resides in a process for preparing olefins by homopolymerizing or copolymerizing olefins in the presence of a catalyst comprising a solid catalyst component and an organometallic compound, which solid catalyst component comprises a substance obtained by the reaction of at least the following four components:: (1) a compound represented by the general formula R' m(OR2)nMgX2~m~n, (2) a compound represented by the general formula Me(OR3)pXz~p, (3) a compound represented by the general formula

(4) a halogen-containing titanium compound in which formulae R1, R2, R3 and R7 are each a hydrocarbon radical having 1 to 24 carbon atoms, R4, R5 and R6 are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen or halogen, X is halogen, Me is an element of Groups I through VIII in the Periodic Table, provided that silicon and titanium are excluded, z is the valence of Me, and m, n, p and q are as follows: O < m~2,0~n < 2,0 < m+n~2,0 < p~z,1 ~q~30.

The catalyst of the present invention exhibits an extremely high polymerization activity, and consequently the partial pressure of monomer is kept low during polymerization. Furthermore, the bulk density of the resultant polymer is so high that the productivity can be improved. Besides, the amount of catalyst remaining in the resultant polymer at the end of polymerization is so small that the polyolefin manufacturing process can dispense with the catalyst removing step, thus permitting simplification of the polymer treating process, and as a whole polyolefins can be prepared extremely economically.

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

The present invention has a further advantage such that from the standpoint of particle size of the resultant polymer, the proportion of coarse particles and fine particles below 50,u is small despite of a high bulk density, and that consequently not only it becomes easy to perform a continuous polymerization reaction but also it becomes easy to handle polymer particles, for example, in centrifugal separation in the polymer treating process and in powder transportation.

As a still further advantage of the present invention, polyolefins prepared by using the catalyst of the present invention have a high bulk density as previously noted, and those having a desired melt index are obtainable with a lower hydrogen concentration than in the conventional processes, thus permitting the total pressure to be set at a relatively small value during polymerization, and consequently a great improvement is attainable in point of economy and productivity.

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

Furthermore, polymers obtained by using the catalyst of the present invention have an extremely narrow molecular weight distribution and their hexane extraction is small, thus reflecting a minimized by-production of low grade polymers. Therefore, for example, in the film grade, it is possible to obtain products of good quality superior in anti-blocking and other properties.

The present invention provides a novel catalyst system having many such characteristic features and capable of remedying the above-mentioned drawbacks of the prior art. It is quite surprising that those features should be attainable easily by using the catalyst of the present invention.

Description of the preferred embodiments As compounds of the formula R'm(OR2)nMgX2~m~n used in the present invention, there essentially may be any compounds of the same formula provided R' and R2 are each a hydrocarbon radical having 1 to 24 carbon atoms, but particularly preferred are those wherein R1 and R2 are each an alkyl group.

Examples of such compounds include diethylmagnesium, diisopropylmagnesium, di-nbutylmagnesium, di-sec-butylmagnesium, methylmagnesium chloride, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, n-propylmagnesium chloride, n-butylmagnesium chloride, n-butylmagnesium bromide, sec-butylmagnesium chloride, phenylmagnesium chloride, decyimagnesium chloride, methoxymagnesium chloride, ethoxymagnesium chloride, isopropoxymagnesium chloride, n-butoxymagnesium chloride, n-octoxymagnesium chloride, methylmagnesium methoxide, ethylmagnesium methoxide, n-butylmagnesium ethoxide, secbutylmagnesium ethoxide, and decylmagnesium ethoxide. Complex with a trialkylaluminum is also employable, e.g. a complex of di-n-butylmagnesium and triethylaluminum.

As compounds of the general formula Me(OR3)DXz~,, used in the present invention, mention may be made of various compounds such as NaOR, Mg(OR3)2, Mg(OR3)X, Ca(OR3)2, Zn(OR3)2, Zn(OR3)X, Cd(OR3)2, Al(OR3)3, Al(OR3)2X, B(OR3)3, B(OR3)2X, Ga(OR3)3, Ge(OR3)4, Sn(OR3)4, P(OR3)3, Cr(OR3)2, Mn(OR3)2, Fe(OR3)2, Fe(OR3)3, Co(OR3)2, and Ni(OR3)2, in which formulae R3 may essentially be any hydrocarbon radical having 1 to 24 carbon atoms, but alkyl and aryl groups are particularly preferred.

Preferred examples of such compounds include NaOC4Hg, 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)CI, Al(OC3H7)3, Al(OC4Hg)3, Al(OC6H5)3 B(OC2H5)3, B(OC2H5)2CI, P(OC2H5)3, P(OC6H5)3, and Fe(OC4Hg). Especially preferred in the present invention are compounds represented by the general formulae Mg(OR3)pX2~p, Al(OR3)pX3~p and B(OR3)pX3p, wherein alkyl of C, to C4 and phenyl are especially preferred as R R3.

In compounds of the general formula

used in the present invention, R4, R5 and R6 each may essentially be any of hydrocarbon radicals having 1 to 24 carbon atoms, alkoxy, hydrogen and halogen, but alkyl, aryl, alkoxy and halogen are preferred, and R7 may essentially be any of hydrocarbon radicals having 1 to 24 carbon atoms, but alkyl and aryl groups are preferred.

Examples of such compounds include monomethyltrimethoxysilane, monomethyltriethoxysilane, monomethyltri-n-butoxysilane, monomethyltri-sec-butoxysilane, monomethyltriisopropoxysilane, monomethyltripentoxysi lane, monomethyltrioctoxysilane, monomethyltristearoxysilane, monomethyltriphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropoxysilane, dimethyldiphenoxysilane, trimethylmonomethoxysilane, trimethylmonoethoxysilane, trimethylmonoisopropoxysilane, trimethylmonophenoxysilane, monomethyldimethoxymonochlorosilane, monomethyldiethoxymonochlorosilane, monomethylmonoethoxydichlorosilane, monomethyldiethoxymonochlorosilane, monomethyldiethoxymonobromosilane, monoethyldiphenoxymonochlorosilane, dimethylmonoethoxymonochlorosilane, monoethyltrimethoxysilane, monoethyltriethoxysilane, monoethyltriisopropoxysilane, monoethyltriphenoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiphenoxysilane, triethylmonomethoxysilane, triethylmonoethoxysilane, triethylmonophenoxysilane, monoethyldimethoxymonochlorosilane, monoethyldiethoxymonochlorosilane, monoethyldiphenoxymonochlorosilane, monoisopropyltrimethoxysilane, mono-nbutyitrimethoxysila ne, mono-n-butyltriethoxysilane, mono-sec-butyltriethoxysila ne, monophenyltriethoxysilane, diphenyldiethoxysilane, diphenylmonoethoxymonochlorosilane, monomethoxytrichlorosilane, monoethoxytrichlorosilane, monoisopropoxytrichlorosilane, mono-nbutoxytrichlorosilane, monopentoxytrichlorosilane, monooctoxytrichiorosila ne, monostearoxytrichlorosilane, monophenoxytrichlorosilane, mono-p-methylphenoxytrichlorosilane, dimethoxydichlorosilane, diethoxydichlorosilane, diisopropoxydichlorosilane, di-n-butoxydichlorosilane, dioctoxydichlorosilane, trimethoxymonochlorosilane, triethoxymonochlorosilane, triisopropoxymonochlorosilane, tri-n-butoxymonochlorosilane, tri-sec-butoxymonochlorosilane, tetraethoxysilane, tetraisopropoxysilane, and chain-like or cyclic polysiloxanes having a repeating unit represented by the formula

obtained by condensation of the above compounds.

As halogen-containing titanium compounds used in the present invention, there may be mentioned halides and alkoxyhalides of titanium. As titanium compounds are preferred tetravalent and trivalent titanium compounds. Preferred examples of tetravalent titanium compounds are those represented by the general formula Tl(OR)rX4r wherein R is an alkyl, aryl or aralkyl group having 1 to 24 carbon atoms, X is a halogen atom and r is O~r < 4, such as titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monomethoxytrichlorotitanium, dimethoxydichiorotitanium, trimethoxymonochlorotitanium, monoethoxytrichlorotitanium, diethoxydichlorotitanium, triethoxy monochlorotitanium, monoisopropoxytrichlorotitanium, diisopropoxydichlorotitanium, triisopropoxymonochlorotitanium, monobutoxytrichlorotitanium, dibutoxydichlorotitanium, monopentoxytrichlorotitanium, monophenoxytrichlorotitanium, diphenoxydichlorotitanium, and triphenoxymonochlorotitanium. As trivalent titanium compounds there may be mentioned 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 of the general formula Ti(OR)sX46 with an organometallic compound of a Group I-Ill metal in the Periodic Table in which formula R is an alkyl, aryl or aralkyl group having 1 to 24 carbon atoms, X is a halogen atom and s is 0 < s < 4.Tetravalent titanium compounds are most preferred in the present invention.

In the present invention, the method for obtaining the solid catalyst component by reacting (1) a compound of the general formula R1m(OR2)nX2mn, (2) a compound of the general formula Me(OR3)pXz~p, (3) a compound of the general formula

and (4) a halogen-containing titanium compound, is not specially limited. The components (1 )-(4) may be reacted under heating at a temperature in the range of 20 to 4000 C, preferably 50 to 3000 C, for a period of time usually in the range of 5 minutes to 20 hours, in the presence or absence of an inert solvent, or may be reacted by a co-pulverization treatment, or by suitably combining these methods.

The order of reaction of the components (1 )-(4) is not specially limited, either. The four components may be reacted at a time, or three of them may be reacted followed by reaction of the remaining one component, or two of them may be reacted followed by reaction of one of the remaining two components and then reaction of the remaining one component.

Inert solvents which may be used in the above reaction are not specially limited. Usually, there may be used hydrocarbon compounds and/or derivatives thereof not inactivating Ziegler type catalysts.

Examples of such solvents include various 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.

The apparatus to be used for the co-pulverization is not specially limited, but usually there is employed a ball mill, a vibration mill, a rod mill, or an impact mill. Conditions such as pulverization temperature and pulverization time can be determined easily by those skilled in the art according to the pulverization method adopted. Generally, the pulverization temperature ranges from 0 to 2000 C, preferably 20 to 1000C, and the pulverization time 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 the moisture should be kept to a minimum.

Particularly preferred in the present invention is the method wherein the components (1 )-(4) are reacted in solution, or the method wherein the components (1 )-(3) are reacted in solution and the reaction product is co-pulverized and reacted with the component (4).

As to the ratio of the components (1) and (2) to be used, both too small and too large amounts of the compound of the general formula Me(OR)pXz~p tend to lower the polymerization activity. 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 preparing a high activity catalyst.

The ratio of the components (1) and (3) to be used is such that the amount of component (3) is in the range of 0.1 to 300 g, preferably 0.5 to 200 g, per 100 g of component (1).

The amount of the halogen-containing titanium compound is most preferably adjusted so that the amount of titanium contained in the solid catalyst component is in the range of 0.5 to 20% by weight.

The range of 1 to 10% by weight is especially desirable for obtaining a well-balanced activity per titanium and/or vanadium and that per solid.

In the preparation of the solid catalyst component, it is also preferable to use as component (5) a member or members selected from the group consisting of organic halides, halogenating agents, phosphoric esters, electron donors and polycyclic aromatic compounds, in addition to the components (1 )-(4). The reaction method in the case of using the component (5) is not specially limited. Preferably employed is the method wherein the components (1)-(5) are reacted in solution, or the method wherein the components (1), (2), (3) and (5) are reacted in solution and the reaction product is copulverized with the component (4).

In the case of using the component (5), its amount ranges from 0.01 to 5 moles, preferably 0.05 to 2 moles, per mole of the component (1).

Organic halides which may be used as component (5) are saturated or unsaturated aliphatic hydrocarbons and aromatic hydrocarbons which are partially substituted by halogen. 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, l,l-dichloroethane, 1,2-dichloroethane, 1,2-dichloro-l,l ,2,2-tetrafluoroethane, hexachloroethane, pentachloroethane, 1 1 , 1 2-tetrachloroethane, 1,1 2,2-tetrachloroethane, 1,1,1 - trichloroethane, 1,1 ,2-trichloroethane, l-chloropropane, 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-hexa- chloropropane, octachloropropane, 1,1 ,2-trichloropropane, 1 -chlorobutane, 2-chlorobutane, 1 -chloro- 2-methylpropane, 2-chloro-2-methylpropane, 2,2-dichlorobutane, 1,3-dichlorobutane, 1,4- dichiorobutane, 2,2-dichlorobutane, 1 -chloropentane, 1 -chlorohexane, 1 -chloroheptane, 1 - chlorooctane, 1 -chlorononane, 1 -chlorodecane, vinyl chioride, 1,1 -dichloroethylene, 1,2- dichloroethylene, tetracnloroethylene,3-chloro-1-propene,1,3-dichloropropene, chloroprene, oieyl chloride, chlorobenzene, chloronaphthalene, benzyl chloride, benzylidene chloride, chloroethylbenzene, styrene dichloride, and a-chlorocumene.

Examples of halogenating agents which may be used as component (5) include non-metal halides such as sulfur chloride, PAL3, PCI5 and SiCI4, and non-metal oxyhaiides such as POCI3, COCI2, NOCI2, SOCK, and SO2C12.

Examples of electron donors which may be used as component (5) include alcohols, ethers, ketones, aldehydes, organic acids, organic acid esters, acid halides, acid amides, amines and nitriles.

As alcohols, there may be used, for example, alcohols having 1 to 18 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, allyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, n-amyl alcohol, n-hexyl alcohol, cyclohexyi alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, benzyl alcohol, naphthyl alcohol, phenol, and cresol.

As ethers, there may be used, for example, ethers having 2 to 20 carbon atoms such as dimethyl ether, diethyl ether, dibutyl ether, isoamyl ether, anisole, phenetole, 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 acetaldehyde, propionaldehyde, octylaldehyde, benzaldehyde, and naphthaldehyde.

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

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, 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, benzoyl chloride, toluoyl chloride, and anioyl chloride.

As acid amides, there may be used, for example, acetamide, benzamide and toluamide.

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

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

Phosphoric esters which may be used as component (5) are those 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-butyl phosphate, triphenyl phosphate, tribenzyl phosphate, trioctyl phosphate, tricresyl phosphate, tritolyl phosphate, trixylyl phosphate, and diphenylxylenyl phosphate.

Examples of polycyclic aromatic compounds which may be used as component (5) include naphthalene, phenanthrene, triphenylene, chrysene, 3,4-benzophenanthrene, 1,2-benzochrysene, picene, anthracene, tetraphene,1,2,3,4-dibenzanthracene, pentaphene,3,4-benzopentaphene, tetracene, 1,2-benzotetracene, hexaphene, heptaphene, diphenyl, fluorene, biphenylene, perylene, coronene, bisantene, ovalene, pyrene, perinaphthene, and halogen- and alkyl-substituted derivatives thereof.

The solid catalyst component thus obtained may be supported on oxides of Group Il-lV metals in the Periodic Table, and this mode of use is also adoptable preferably. In this case, not only oxides of Group Il-lV metals in the Periodic Table each alone, but also double oxides of these metals, as well as mixtures thereof, are employable. Examples of such metal oxides include MgO, CaO, ZnO, BaO, SiO2, SnO2, Al203, MgO . Al2O3, SiO2. Al203, MgO . SiO2, MgO . CaO . Al203, and Awl203. CaO, with SiO2, Awl203, SiO2. Al203 and MgO . Al203 being particularly preferred.

The method for supporting the solid catalyst component on the oxide of a Group ll-lV metal in the Periodic Table is not specially limited. As a preferable example, there may be adopted a method wherein the components (1), (2), (3) and also the component (5) if required, are reacted using an ether compound as a solvent in the presence of the metal oxide, then the liquid phase portion is removed by washing, dry up or other suitable means and thereafter the component (4) is added and reacted together with a hydrocarbon such as hexane to obtain a supported solid catalyst component.

As organometallic compound used in the present invention, there may be mentioned organometallic compounds of Group l-lV metals in the Periodic Table which are known as a component of Ziegler type catalysts, with organoaluminum compounds and organozinc compounds being particularly preferred.Examples of such compounds include organoaluminum compounds of the general formulae R3Al, R2AIX, RAIX2, R2AIOR, RAI(OR)X and R3AI2X3 wherein R, which may be alike or different, is an alkyl, aryl or aralkyl group having 1 to 24 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 24 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 organocarboxylic acid esters such as ethyl benzoate, ethyl o- or p-toluylate and ethyl panisate.The amount of the organometallic compound to be used is not specially limited. Usually, it may range from 0.1 to 1,000 moles per mole of the titanium compound and/or vanadium compound.

The olefin polymerization using the catalyst of the present invention may be carried out in the form of slurry polymerization, solution polymerization or vapor phase polymerization, with vapor phase polymerization being particularly suitable. The polymerization reaction is performed in the same way as in the conventional olefin polymerization reaction using a Ziegler type catalyst; that is, the reaction is conducted in a substantially oxygen- and water-free condition and in the presence or absence of an inert hydrocarbon. Olefin polymerizing conditions involve temperatures in the range of 20 to 1200 C, preferably 50 to 1000C, and pressures ranging from atmospheric 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 the polymerization temperature and the 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, there can be performed, without any trouble, two or more multi-stage polymerization reactions invoiving 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 can be polymerized with a Ziegler type catalyst, with a-olefins having 2 to 12 carbon atoms being particularly preferred. For example, it is suitable to the homopolymerization of a-olefins such as ethylene, propylene, butene-1, hexene-1, 4-methylpentene-1 and octene-1 , the copolymerization of ethylene and propyiene, ethylene and butene-1, ethylene and hexene-1 , ethylene and 4-methylpentene-1, ethylene and octene-1, and propylene and butene-1, and the copoiymerization of ethylene and other two or more cr-olefins.

There also may be conducted copolymerization with dienes for the purpose of modification of polyolefins. Examples of diene compounds which may be used in this copolymerization include butadiene, 1,4-hexadiene, ethylidene norbornene and dicyclopentadiene.

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

Example 1 (a) Preparation of a solid catalyst component Into a three-necked 500 ml flask equipped with a stirrer were charged 200 ml of ethanol, 20 g of ethoxymagnesium chloride (Mg/CI mole ratio=0.81) obtained by treating magnesium diethoxidewith HCI, 15 g of aluminum tri-sec-butoxide and 20 g of tetraethoxysilane, and reaction was allowed to take place for 3 hours under reflux of ethanol. Thereafter, the ethanol was dried off, then 200 ml of hexane and 5 ml of titanium tetrachloride were added and reacted for 2 hours under reflux of hexane.

Thereafter, the supernatant liquid was removed to obtain a solid catalyst component, which was washed with hexane three times. The solid catalyst component proved to contain 25 mg of titanium per gram thereof.

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

Into the autoclave adjusted to 800C were fed the solid catalyst component prepared above and triethylaluminum at the rates of 50 mg/hr and 5 mmol/hr, respectively, and ethylene, butene-1 and hydrogen gases were introduced while adjusting to give a butene-1/ethylene mole ratio of 0.27 in the vapor phase within the autoclave and a hydrogen concentration of 1 5% of the total pressure.

Polymerization was carried out while recycling the intra-system gases by the blower to maintain the total pressure at 10 kg/cm2. G. The ethylene copolymer thus prepared had a bulk density of 0.28, a melt index (MI) of 1.2 and a density of 0.9203. The catalyst activity was 254,000 g . 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 of the autoclave and the stirrer proved to be clean with no polymer adhesion thereto.

The F.R. value (F.R.=MI,JMI2,6) 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 My2,6 thereof determined at a load of 2.16 kg both at 1 900C according to the method defined by ASTM-D1238-65T was 7.2 and thus the molecular weight distribution of the copolymer was very narrow.

A film was formed from the copolymer and extracted in boiling hexane for 10 hours; as a result, its hexane extraction was 1.3 wt% and thus very small.

Comparative Example 1 A solid catalyst component was prepared in the same way as in Example 1 except that tetraethoxysilane was not added. It contained 21 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 1 except that the solid catalyst component just prepared above was fed at the rate of 50 mg/hr. The ethylene copolymer thus prepared had a bulk density of 0.25, a density of 0.9213 and a melt index of 1.2. The catalyst activity was 186,000 g . copolymer/g . Ti.

The F.R. value of the copolymer was 8.2. A film was formed from the copolymer and extracted in boiling hexane for 10 hours; as a result, its hexane extraction proved to be 4.2 wt. %.

Example 2 (a) Preparation of a solid catalyst component A solid catalyst component was prepared in the same way as in Example 1 except that 1 5 g of boron triethoxide was used in place of 1 5 g of aluminum tri-sec-butoxide. It contained 27 mg of titanium per gram thereof.

(b) Polymerization 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 prepared above was fed at the rate of 50 mg/hr. The ethylene copolymer thus prepared had a bulk density of 0.27, a density of 0.91 95 and a melt index of 1.1. The catalyst activity was 223,000 g. 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 inner wall of the autoclave and the stirrer proved to be clean with no polymer adhesion thereto.

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

Example 3 (a) Preparation of a solid catalyst component A solid catalyst component was prepared in the same way as in Example 1 except that 20 g of a pentamer of tetraethoxysilane was used in place of 20 g of tetraethoxysilane. It contained 21 mg of titanium per gram thereof.

(b) Polymerization A continuous vapor phase polymerization of ethylene and butene-1 was carried out in the same manner as in Example 1 except that the solid catalyst component just prepared above was fed at the rate of 50 mg/hr. The ethylene copolymer thus prepared had a bulk density of 0.34, a density of 0.9200 and a melt index of 1.0. The catalyst activity was 332,000 g. 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 inner wall of the autoclave and the stirrer proved to be clean with no polymer adhesion thereto.

The F.R. value of the copolymer was 7.2. A film was formed from the copolymer and extracted in boiling hexane for 10 hours; as a result, its hexane extraction was 1.3 wt. % and thus very small.

Example 4 (a) Preparation of a solid catalyst component Into a three-necked 500 ml flask equipped with a stirrer were charged 200 ml of n-hexane, 20 g of n-butylmagnesium chloride, 1 5 g of aluminum triethoxide and 20 g of triethoxymonochlorosilane, and reaction was allowed to take place 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 solid substance just prepared above 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 obtain a solid catalyst component which contained 27 mg of titanium per gram thereof.

(b) Polymerization 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 just prepared above was fed at the rate of 50 mg/hr. The ethylene copolymer thus prepared had a bulk density of 0.31, a density of 0.9205 and a melt index of 1.1. The catalyst activity was 248,000 g . 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 inner wall of the autoclave and the stirrer proved to be clean with no polymer adhesion thereto.

The F.R. value of the copolymer was 7.5. A film was formed from the copolymer and extracted in boiling hexane for 10 hours; as a result, its hexane extraction was 1.4 wt. % and thus very small.

Example 5 A stainless steel 2 liter autoclave equipped with an induction stirrer was purged with nitrogen and then charged with 1,000 ml of hexane, then 1 mmol of triethylaluminum and 20 mg of the solid powder obtained in Example 1 were added and the temperature was raised to 900C with stirring. The system was pressurized to 2 kg/cm2 . G due to the vapor pressure of hexane. Hydrogen was introduced until the total pressure was 4.8 kg/cm2 . G, then ethylene was introduced so as to maintain the total pressure at 10 kg/cm2 . G, and polymerization was allowed to take place for 1 hour. Thereafter, the polymer slurry was transferred into a beaker and hexane removed under reduced pressure to yield 1 83 g of a white polyethylene having a melt index of 1.3 and a bulk density of 0.33. The catalyst activity was 70,400 g . polyethylene/g. Ti . hr. C2H4 pressure,1,760 g . polymer/g . solid . hr. C2H4 pressure.

The F.R. value of the polyethylene was 8.2 and thus the molecular weight distribution was very narrow. Its hexane extraction was 0.15 wt. % and thus very small.

Claims (14)

Claims

1. A process for preparing a polyolefin by polymerizing at least one olefin in the presence of a catalyst, said catalyst comprising a solid catalyst component and an organometallic compound, said solid catalyst component comprising a substance obtained by the reaction of at least the following four components:: (1) a compound represented by the general formula R1m(0R2)nM9X2~m-nt (2) a compound represented by the general formula Me(OR3)pXz~p, (3) a compound represented by the general formula

(4) a halogen-containing titanium compound in which formulae R', R2, R3 and R7 are each a hydrocarbon radical having 1 to 24 carbon atoms, R4, R5 and R6 are each a hydrocarbon radical having 1 to 24 carbon atoms, alkoxy, hydrogen or halogen, X is halogen, Me is an element of Groups 1-VIll in the Periodic Table provided that silicon and titanium are excluded, z is the valence of Me, and m, n, p and q are as follows: O < m < 2,0n < 2,0 < m+n < 2,0 < puz,1 q < 30.

2. The process of claim 1 wherein said components (1) and (2) are used in a ratio ranging from 1/0.001 to 1/20 in terms of Mg/Me mole ratio.

3. The process of claim 1 or claim 2 wherein said components (1) and (3) are used in a ratio such that the amount of said component (3) is in the range of 0.1 to 300 grams per 100 grams of said component (1).

4. The process of claim 1, 2 or 3 wherein said component (4) is used in an amount ranging from 0.5 to 20% by weight in terms of titanium contained in said solid catalyst component.

5. The process of any one of claims 1 to 4 wherein Me is Na, Mg, Ca, Zn, Al, B, P, or Fe.

6. The process of any one of claims 1 to 5 wherein said halogen-containing titanium compound is a titanium halide or a titanium alkoxyhalide.

7. The process of any one of claims 1 to 6 wherein said solid catalyst component comprises a substance obtained by reacting said components (1) through (4) with a component (5), said component (5) comprising at least one member selected from the group consisting of organic halides, halogenating agents, phosphoric esters, electron donors and polycyclic aromatic compounds.

8. The process of claim 7 wherein said component (5) is used in an amount of 0.01 to 5 moles per mole of said component (1).

9. The process of any one of claims 1 to 6 wherein said solid catalyst component is supported on an oxide of a Group ll-lV metal in the Periodic Table.

1 0. The process of any one of claims 1 to 9 wherein said -organometallic compound is an organoaluminum compound or an organozinc compound.

11. The process of any one of claims 1 to 10 wherein the polymerization reaction is carried out at a temperature ranging from 20 to 1200C and at a pressure ranging from atmospheric pressure to 70 kg/cm2.

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

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

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

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

1 6. As a new composition of matter, the solid catalyst component defined in any one of claims 1 to 9.