Supported polymerization catalyst (P-1180).

DESCRIPTION

This invention relates to a supported catalyst component containing transition metal, useful in combination with a cocatalyst for the polymerization and copolymerization of olefins and particularly useful for the polymerization of ethylene and copolymerization of ethylene with 1 olefins having 3 or more atoms carbon such as, for example, propylene, isobutene, 1 butene, 1-pentene, 1-hexene, 1-octene, cyclic olefins such as norbornene, and dienes such as butadiene, 1,7-octadiene and 1,4-hexadiene. The invention also relates to a heterogeneous catalyst system comprising the supported catalyst component containing transition metal and, as cocatalyst, the combination of an organometallic compound of a metal selected from Groups IA, IIA, IIB, and IIIA of the Periodic Table (Edition 66- of the Handbook of Chemistry and Physics, CRC Press, 1985-1986, CAS version) and an alumoxane. The invention generally relates to a process for polymerization of ethylene alone or with other 1-olefins or diolefins in the presence of a catalyst system comprising the catalyst component containing supported transition metal and an alumoxane.

Traditionally, ethylene and 1-olefins have been polymerized or copolymerized in the presence of hydrocarbon insoluble catalyst systems comprising a compound of a transition metal and an alkyl aluminum. More recently, it has been found that active homogenous catalyst systems comprising a bis (cyclopentadienyl) titanium dialkyl or a bis (cyclopentadienyl) zirconium dialkyl, an aluminum trialkyl and water are useful for the polymerization of ethylene.

German Patent Application 2,608,863 describes the use of a catalyst system for the polymerization of ethylene consisting of bis (cyclopentadienyl) titanium dialkyl, aluminum trialkyl and water.

German Patent Application 2,608,933 describes a catalyst system for the polymerization of ethylene consisting of zirconium-metallocenes of the general formula (cyclopentadienyl) nZrY4-n, where n represents a number in the range of 1 to 4, and represents R , CH2AlR2, CH2CH2AlR2 and CH2CH (AlR2) 2, where R represents alkyl or metalloalkyl, and a trialkyl aluminum cocatalyst and water.

EP-A-0035242 describes a process for preparing ethylene polymers and atactic propylene polymers in the presence of a halogen-free Ziegler catalyst system comprising (1) a cyclopentadienyl compound of the formula (cyclopentadienyl) nMeY4-n in which n is an integer from 1 to 4, Me is a transition metal, especially zirconium, and Y is either hydrogenic, a C1-C5 alkyl or metal-alkyl group or a radical having the following general formula CH2AlR2, CH2CH2AlR2 and CH2CH (AlR2) 2 in which R represents an alkyl or metal-C1-C5 alkyl group, and (2) an alumoxane.

Additional teachings of homogeneous catalyst systems comprising a metallocene and alumoxane are EP-A-0069951 of Kaminsky et al, and US 4,404,344, issued September 13, 1983, of Sinn et al.

In "Molecular Weight Distribution and Stereoregularity Of Polypropylenes Obtained WithTi (OC4H9) 4 / Al (C2H5) 3 Catalyst System", Polymer, p. 469-471, 1981, Vol. 22, April, Doi et al describe the polymerization of propylene with a catalyst that at approximately 41 ° C obtains a fraction of soluble catalyst and insoluble catalyst, one of them with "homogeneous catalytic centers" and the another with "heterogeneous catalytic centers". Polymerization at said temperature obtains polypropylene having a bimodal molecular weight distribution.

An advantage of the homogeneous metallocene-alumoxao catalyst system is the very high activity obtained for the polymerization of ethylene. However, the catalysts have a disadvantage, namely that the ratio of alumoxane to metallocene is high, for example, of the order of 1000 to greater. Such bulky amounts of alumoxane will require extensive treatment of the polymer product obtained in order to separate undesirable aluminum. Another disadvantage of the homogeneous catalyst system is that the polymer product produced therefrom has a small particle size and low bulk density.

EP-0128045 describes a homogeneous catalyst system comprising two different metallocenes for use in the production of polyolefins having a wide molecular weight distribution and / or a multi modal molecular weight distribution.

EP-A-128046 describes a homogeneous catalyst system comprising two or more metallocenes, each of which has different reactivity ratios, for use in the production of reactor mixtures, that is, mixtures of two or more polymers that they have a varied distribution of compositions produced simultaneously in a reactor.

James CW Chien, in "Reduction of Ti (IV) Alkyls in Cab - O - Sils Surfaces", Journal of Catalysis 23, 71 (1971); Dag Slotfeldt - Ellingsene et al in "Heterogenization of Homogeneous Catalysis", Journal Molecular Catalysis, 9, 423 (1980), describe a titanocene supported in combination with alkyl-aluminum halides as poor catalysts for the polymerization of olefins.

It would be highly desirable to provide a metallocene-based catalyst that is commercially useful for the polymerization of olefins in which the ratio of aluminum to transition metal is reduced in comparison with known homogeneous systems, to provide a polymerization catalyst system that allows obtaining a product Polymer having improved particle size and bulk density, and providing a catalyst system that demonstrates the improved incorporation of comonoimers in the production of, for example, linear low density polyethylene (LLDPE). It is particularly desirable to provide a sis2

016 259 subject catalyst capable of producing polymers having a varied range of molecular weight distributions and / or compositional distributions.

In accordance with the present invention, a catalyst system is provided comprising (i) a metallocene supported catalyst component and non-metallocene transition metal compound (ie, a transition metal compound that does not contain the cyclopentadienyl ring) and (ii) a combination of an organometallic compound of a metal of Groups IA, IIA, IIB and IIIA of the Periodic Table and an alumoxane cocatalyst in which the molar ratio of alumoxane to metallocene was in the range of 1: 1 to 100: 1, for the polymerization of olefins, and particularly for the production of linear polyethylenes of low, medium and high density and copolymers of ethylene with alpha-olefins that have 3 carbon atoms (C3-C18), cyclic olefins, and / or diolefins that have up to 18 carbon atoms.

The supported catalyst component provided in accordance with an embodiment of this invention comprises the product obtained by contacting at least one metallocene and at least one transition metal compound that does not contain cyclopentadienyl and a support material thus providing a catalyst component of supported olefin polymerization of transition metal compound (multi) metallocene - non - metallocene.

According to another embodiment of the invention, a catalyst system is provided comprising a (multi) metallocene-supported non-cyclopentadienyl transition metal compound and an alumoxane-organometallic compound that polymerized olefins with commercially acceptable rates without an inconvenient excess of alumoxane as required in the homogeneous system.

In a further embodiment of this invention, a process is provided for the polymerization of ethylene and other olefins, and particularly homopolymers of ethylene and copolymers of ethylene and alpha-olefins and / or diolefins in the presence of the new catalyst system. The process, by means of the catalyst, provides the ability to produce polymers having a varied range of molecular weight distributions, that is, from a narrow molecular weight distribution to a wide molecular weight distribution and / or multi-modal distribution of molecular weights The process also provides the ability to produce polyethylene reactor mixtures with copolymers of selected composition polyethylene.

The metallocenes used in the production of the supported catalyst component are organometallic coordination compounds that are cyclopentadienyl derivatives of a metal of Groups IVB and VB of the Periodic Table and include mono, di and tricyclopentadienyls and their derivatives of transition metals. Metallocenes of metals such as titanium, zirconium, hafnium and vanadium are particularly desirable.

The transition metal compounds used in the production of the supported catalyst component are coordination compounds of a Group IVB, VB or VIB metal, excluding cyclopentadienyl derivatives, but including halide, alkoxide, oxyhalide, and hydride derivatives of the metals of transition. Particularly desirable are the metal derivatives of Gruos IVB and VB such as titanium, zirconium and vanadium.

The alumoxanes used as a component of the cocatalyst system are in themselves the reaction products of an aluminum-trialkyl with water.

Alumoxanes are well known in the art and comprise oligoomeric, linear and / or cyclic alkyl-alumoxanes represented by the formulas:

(I) R - (Al - O) n -AlR2 for alumoxanes ^|

R linear oligoomers, and (II) (- Al - O -) m for alumoxanes ^|

R cyclic oligomers, where n is 1-40, preferably 1-20, m is 3 40, preferably 3-20 and R is a C1-C8 alkyl group and preferably methyl. Generally, in the preparation of alumoxanes from, for example, trimethylaluminum and water, a mixture of linear and cyclic compounds is obtained.

Alumoxanes can be prepared in a variety of ways. Preferably, they are prepared by contacting water with an aluminum-trialkyl solution, such as, for example, trimethylaluminum, in a suitable organic solvent such as benzene or an aliphatic hydrocarbon. For example, aluminum-alkyl is treated with water in the form of a humid solvent. In a preferred method, the aluminum-alkyl, such as trimethyl-aluminum, may be desirably contacted with a hydrated salt such as hydrated ferrous sulfate. The method comprises treating a dilute solution of trimethyl aluminum in, for example, toluene with ferrous sulfate heptahydrate.

In summary, the catalyst component containing (multi) supported transition metal of the present invention is obtained by contacting at least one metallocene and at least one non-cyclopentadienyl transition metal compound (hereinafter referred to as "transition metal compound" ) with a solid porous support material. The supported product is used as the catalyst component containing transition metal for the polymerization of olefins.

Typically, the support can be any particularly porous solid support such as talc or inorgaonic oxides, or resinous support materials such as a polyolefin. Preferably, the support material is a finely divided inorgaonic oxide.

Suitable inorgaonic oxide materials that are desirably employed in accordance with this invention include Group IIA, IIIA, IVA or IVB metalic oxides such as solid, alumina, solid-alumina and mixtures thereof. Others

016 259 inorganic oxides that can be used alone or in combination with silica, alumina or silica alumina are magnesium oxide, titanium dioxide, and zirconium dioxide. However, other suitable support materials may be used.₅two, for example, finely divided polyolefins such as finely divided polyethylene.

Metallic oxides generally contain acidic surface hydroxyl groups that reacted with the metallocene added to the thick reaction suspension. Before use, the inorganic oxide support is dehydrated, that is, it is subjected to a thermic treatment in order to remove water and reduce the concentration of surface hydroxyl groups. He tries-₁₅This is carried out under vacuum or while purged with a dry inert gas such as nitrogen at a temperature of 100 ° C to 1000^orC, and preferably, from 300 ° C to 800 ° C. Pressure considerations are not critical. The duration of the work₂₀Thermal treatment can be from 1 to 24 hours; however, shorter or longer times may be used as long as equilibrium is established with the surface hydroxyl groups.

The dehide can be used advantageously ₂₅chemical drafting as an alternative method of dehydration of the support material of metal oxide. Chemical dehydration converts all water and hydroxyl groups on the surface of the oxide into inert chemical species₃₀tes. Useful chemical agents are, for example,

SiCl4; chlorosilanes, such as trimethylchlorosilane and dimethylaminotrimethylsilane. The chemical dehydration is carried out by putting the inorgaonic material constituted by particles in thick suspension,₃₅ such as, for example, solid in a low boiling inert hydrocarbon, such as, for example, hexane. During the chemical dehydration reaction, the solid must be kept in an atmosphere free of moisture and oxygen.₄₀

A solution in low-boiling inert hydrocarbon of the chemical dehydrating agent, such as, for example, dichlorodimethylsilane, is then added to the thick silica suspension. The solution is slowly added to the heavy suspension. The temperature ranges during the chemical dehydration reaction can be 25^°C to 120^°C; however, higher and lower temperatures can be used. Preferably, the temperature would be 50^°Ca70^°C. Must ₅₀ allow the chemical dehydration process to proceed until all moisture has been removed from the support material consisting of particles, which is indicated by the cessation of gas evolution. Normally, it will be left₅₅ that the chemical dehydration reaction proceeds for 30 minutes to 16 hours, preferably 1 to 5 hours. Once the chemical dehydration is complete, the solid material constituted by particles is filtered into the atmosphere of₆₀nitrogen and washed once or more times with a dry and oxygen-free inert hydrocarbon solvent. The washing solvents, as well as the diluents used to form the thick suspension and the solution of the dehydrated chemical agent₆₅Thus, they can be any suitable inert hydrocarbon. Illustrative of such hydrocarbons are heptane, hexane, toluene, isopentane and anaologists.

The metallocene normally soluble in hydrocarbons is converted into a heterogeneous supported catalyst by simply depositing said at least one metallocene on the support material.

Any of the conventional Ziegler-Natta transition metal compounds can be usefully used as the transition metal component in the preparation of the supported catalyst component. Typically, the transition metal component is a compound of a Group IVB, VB, or VIB metal. The transition metal component is generally represented by the formulas: TrX'4-q (OR ') q, TrX'4-qR²q, VOX'3 and VO (OR ') 3. Tr is a metal of Groups IVB, VB or VIB, preferably titanium, vanadium or zirconium; q is 0 or a number equal to or less than 4, X 'is a halogen and R¹it is an alkyl group, aryl group or cycloalkyl group having 1 to 20 carbon atoms, and R²it is an alkyl group, aryl group, aralkyl group, substituted aralkyl group, and analogs. The substituted aryls, aralkyl and aralkyl contain from 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. When the transition metal compound contains a hydrocarbyl group,

R², which is an alkyl, cycloalkyl, aryl, or aralkyl group, the hydrocarbyl group preferably did not contain an H-atom in the beta position with respect to the metal-carbon bond. Illustrative, but not limiting, examples of the alkyl group are methyl, neo-pentyl, 2,2-dimethylbutyl, 2,2 dimethylhexyl; aryl groups such as phenyl, naphthyl; aralkyl groups such as benzyl; cycloalkyl groups such as 1-norbornyl. Mixtures of these transition metal compounds may be employed, if desired.

Illustrative examples of the transition metal compounds include TiCl4, TiBr4, Ti (OC2H 5) 3Cl, Ti (OC2 H5) Cl3, Ti (OC4H 9) 3Cl, Ti (OC3 H7) 2Cl2, Ti (OC6H13) 2Cl2, Ti ( OC8H17) 2Br2, and Ti (OC12 H25) Cl3. Illustrative examples of vanadium compounds include VCl4, VOCl3, CO (OC2H5) 3, andVO (OC4H9) 3. Illustrative examples of zirconium compounds include ZrCl4, ZrCl3 (OC2H5), ZrCl2 (OC2H5) 2, ZrCl (OC2H5) 3, Zr (OC2H5) 4, ZrCl3 (OC4H9), ZrCl2 (OC4H9) 2, and ZrCl (OC4H9) 3.

As indicated above, mixtures of the transition metal compounds can be used lately, with no restriction imposed on the number of transition metal compounds that can be contacted with the support and one or more metallocenes. Any halide compound - and alkoxide - transition metal, or mixtures thereof can be used lately. Especially preferred are the aforementioned transition metal compounds, with vanadium tetrachloride, vanadium oxychloride, and titanium tetrachloride being the most preferred.

The present invention employs at least one metallocene compound in the formation of the supported catalyst. The metallocene, that is, a cyclopentadienide, is a metalic derivative of a cyclopentadiene. The metallocenes used lately according to this invention contain at least one cyclopentadiene ring. The

016 259 me such is selected from the metals of Groups IVB, or VB, preferably titanium, zirconium, hafnium, and vanadium, and especially titanium and zirconium. The cyclopentadienyl ring may be unsubstituted or contain substituents such as, for example, hydrocarbyl substituents. The metallocene may contain one, two, or three cyclopentadienyl rings; however, two rings are preferred.

Metallocenes can be represented by the general formulas:

(Cp) mMRnXq where Cp is a cyclopentadienyl ring, M is a transition metal of Group IVB or VB, R is a hydride or hydrocarbyl group having 1 to 20 carbon atoms, X is a halogen atom, m = 1-3, n = 0-3, q = 0-3 and the sum of m + n + q is equal to the oxidation state of M.

II. (C5R'k) gR ”S (C5R'k) MQ3-g and

III. R "S (C5R'k) 2MQ 'where (C5R'k) is a substituted cyclopentadienyl or cyclopentadienyl, each R' is the same or different and is hydrogen or a hydrocarbyl radical such as alkyl, alkenyl, aryl, alkylaryl radical, or arylalkyl containing from 1 to 20 carbon atoms or two carbon atoms are attached to each other to form a C4-C6 ring, R "is a C1-C4 alkylene radical, a dialkyl-germanium or silicon, or an alkyl-phosphine or amine radical that forms a bridge between two rings (C5R'k), Q is a hydrocarbyl radical such as aryl, alkyl, alkenyl, alkylaryl, or aryl-alkyl radical having carbon atoms, hydrocarbon radical having 1 to 20 carbon atoms or halogen and may be the same or different from each other, Q 'is an alkylidene radical having 1 to about 20 carbon atoms, ses0oó1, ges0,1óo2, ses0cuandoges0, k is 4 when s is one, and k is 5 when s is 0, and M is as defined above.

Illustrative hydrocarbyl radicals are methyl, ethyl, propyl, butyl, amyl, isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl, 2-ethylhexyl, phenyl and anaologists.

Illustrative halogen atoms include chlorine, bromine, fluorine and iodine, and among these halogen atoms, chlorine is preferred.

Illustrative hydrocarboxy radicals are methoxy, ethoxy, butoxy, amyloxy and analogs.

As illustrative alkylidene radicals there may be mentioned methylidene, ethylidene and propylidene.

Illustrative but not limiting examples of metallocenes represented by the formula

I are dialkyl metallocenes such as bis (cyclopentadienyl) titanium dimethyl, bis (cyclopentadienyl) titanium diphenyl, bis (cyclopentadienyl) zirconium dimethyl, bis (cyclopentadienyl) zirconium diphenyl, bis (cyclopentadienyl) hafnium dimethyl and diphenyl, bis cyclopentadienyl) titanium dineopentyl, bis (cyclopentadienyl) zirconium dineopentyl, bis (cyclopentadienyl) titanium dibenzyl, bis (cyclopentadienyl) zirconium dibenzyl, bis (cyclopentadienyl) vanadium dimethyl; mono-alkyl metallocenes such as bis (cyclopentadienyl) titanium methyl chloride, bis (cyclopentadienyl) titanium ethyl chloride, bis (cyclopentadienyl) titanium phenyl chloride, bis (cyclopentadienyl) zirconium methyl chloride, chloride bis (cyclopentadienyl) zirconium-ethyl, bis (cyclopentadienyl) zirconium-phenyl chloride, bis (cyclopentadienyl) titanium-methyl bromide, bis (cyclopentadienyl) titanium-methyl iodide, bis (cyclopentadienyl) titanium-ethyl bromide, bis (cyclopentadienyl) titanium-ethyl iodide, bis (cyclopentadienyl)-titanium-phenyl bromide, bis (cyclopentadienyl) titanium-phenyl iodide, bis (cyclopentadienyl) zirconium-methyl bromide, bis (cyclopentadienyl) zirconium-methyl iodide , bis (cyclopentadienyl) zirconium-ethyl bromide, bis (cyclopentadienyl) zirconium-ethyl bromide, bis (cyclopentadienyl) zirconium-ethyl iodide, bis (cyclopentadienyl) zirconium-phenyl bromide, bis (cyclopentadienyl) zirconium-phenyl iodide; the trialkyl

- metallocenes such as cyclopentadienyl titanium

- trimethyl, cyclopentadienylzirconium - triphenyl, and cyclopentadienylzirconium - trineopentyl, cyclopentadienylzirconium - trimethyl, cyclopentadienylhafnium

- triphenyl, cyclopentadienylhafnium - trineopentyl, and cyclopentadienylhafnium - trimethyl.

Illustrative, but not limiting, examples of the metallocenes II and III which can be used useful in accordance with this invention are monocyclopentadienyl titanocenes such as pentamethylcyclopentadienyl titanium trichloride, pentaethylcyclopentadienyl titanium trichloride, bis (pentamethylcyclopentadyl titanium, titanium diphenylcyclopentadyl titanium trichloride Carbine represented by the Cp2Ti = CH2 formula and derivatives of this reagent such as Cp2Ti = CH2 ^. Al (CH3) 3, (Cp2TiCH2) 2, and

Cp2TiCH2CH (CH3) CH2, Cp2Ti-CH2CH2CH2; substituted bis (Cp) Ti (IV) compounds such as titanium diphenyl or dihalides; dialkyl, trialkyl, tetraalkyl and pentaalkyl cyclopentadienyl titanium compounds such as bis (1,2-dimethylcyclopentadienyl) titanium diphenyl or dichloride, bis (1,2-diethylcyclopentadienyl) titanium diphenyl or dichloride and other dihalide complexes; cyclopentadiene complexes bridged with silicon, phosphine, amine or carbon, such as dimethyl silyldyl

- cyclopentadienyl titanium diphenyl or dichloride, methyl phosphine dicyclopentadienyl titanium diphenyl or dichloride, methylene dichlorpentadienyl titanium diphenyl or dichloride and other dihalide complexes.

Illustrative but non-limiting examples of the Formula II and III zirconocenes that can be used useful in accordance with this invention are pentamethylcyclopentadienyl zirconium trichloride, pentaethylcyclopentadienyl zirconium trichloride, cyclopentadiene dichloromethyl dimethyl dichloride, such as alkyl, dimethylthiocyl dimethyl dichloride , bis (e

- fenilpropilciclopentadienil) zirconium - dimethyl, bis (methylcyclopentadienyl) zirconium - dimethyl, bis (n - butylcyclopentadienyl) zirconium - dimethyl bis (cyclohexylmethylcyclopentadienyl) zirconium - dimethyl, bis (n - octyl - cyclopentadienyl) - zirconium - dimethyl and complexes haloalkyl and dihalide of the above; dialkyl, trialkyl, tetraalkyl, and pentaalkylcyclopentadiene, such as bis (pentamethylcyclopentadienyl) -zirconium-diphenyl, bis (pentamethylcyclopentadienyl) zirconium-dimethyl, bis (1,2-dimethylcyclopentadienyl) zirconium dimethyl and mono-and dihal mono-complexes; cyclopentadiene bridge complexes5

016 259 two with silicon, phosphorus and carbon such as dimethylsilyldicyclopentadienyl-zirconium-dimethyl, methyl halide or dihalide, and methylene-dicyclopentadienyl-zirconium-dimethyl, methyl halide or dihalide, carbons represented by the formulas Cp2 = Zr = CH2 P (C6 = CH6 P (C6 = CH2 = P5 ) 2CH3, and derivatives of these compounds such as Cp2ZRCH2CH (CH3) CH2.

Bis (cyclopentadienyl) hafnium dichloride, bis (cyclopentadienyl) hafnium-dimethyl, bis (cyclopentadienyl) vanadium dichloride and analogs are illustrative of other metallocenes.

The treatment of the support material, as mentioned above, is carried out in an inert solvent. The same inert solvent or a different inert solvent can also be used to dissolve the metallocenes and, if desired and / or required, the transition metal component. Preferred solvents include mineral oils and the various hydrocarbons that are liquid at the reaction temperatures and in which the metallocenes are soluble. Illustrative examples of useful solvents include alkanes such as pentane, iso-pentane, hexane, heptane, octane and nonane; cycloalkanes such as cyclopentane and cyclohexane; and aromotics such as benzene, toluene, ethylbenzene and diethylbenzene. Preferably, the support material is suspended in toluene and the metallocene (s) dissolved in toluene before addition to the support material. The transition metal component or components may (n) be contacted with the support material together with the metallocene (s) by dissolution or suspended in the solvent, may be contacted separately and simultaneously as a solution or in solution. pure state with the support, or the transition metal component may be contacted before or after the metallocene comes into contact with the support material. The amount used should provide adequate heat transmission away from the catalytic components during the reaction and allow a satisfactory mixing.

The metallocene or metallocenes and the transition metal component or components can be added to the support material quickly or slowly. The temperature maintained during the contact of the reactants can vary widely, such as, for example, from 0 ° to 100 ° C. Higher or lower temperatures can also be used. Preferably, the contacting of the at least one metallocene and the at least one transition metal compound with the solid is carried out at room temperature. The reaction between the at least one metallocene and the support material is rapid; however, it is desirable that the at least one metallocene be contacted with the support material for approximately one hour to eighteen hours or more. Preferably, the reaction is maintained for about an hour. The reaction of the at least one metallocene with the support material is evidenced by elementary anaolysis of the support material for the transition metal contained in the metallocene (s).

At all times, the individual ingredients, as well as the recovered catalyst component, are protected against oxygen and moisture. Therefore, the contact must be carried out in an atmosphere free of oxygen and moisture and recovered in an atmosphere free of oxygen and moisture. Preferably, therefore, the contacting is carried out in the presence of a dry inert gas such as, for example, nitrogen. The recovered solid catalyst is maintained in a nitrogen atmosphere.

Upon completion of the contact of at least one metallocene and at least one transition metal component with the support, the solid catalyst component can be recovered by any well known technique. For example, the solid material can be recovered from the liquid by evaporation under vacuum, filtration or decantation. The solid is then dried by any suitable drying technique, such as drying in pure dry nitrogen stream or vacuum drying.

The total amount of metallocene used useful in the preparation of the solid supported catalyst component may vary within a wide range. The metallocene concentration deposited on the essentially dry support may be between 0.001 and 5 millimoles / g of support; however, larger or smaller amounts can be used useful. Preferably, the metallocene concentration was in the range of 0.010 to 2 mmol / g of support, and especially 0.03 to 1 mmol / g of support.

The molar ratio of the metallocene component to the transition metal component can vary within a wide range, and according to this invention it is only limited by the desired amplitude of the molecular weight distribution. The ratio may be in the range of 100 to 0.01 and preferably 10 to 0.1 moles of metallocene component per mole of transition metal component.

It is highly desirable to have for many applications, such as extrusion and molding processes, polyethylenes having a wide molecular weight distribution (BMWD) of the "broad molecular weight distribution" English of the unimodal or multimodal type. Such polyethylenes exhibit an excellent ability to be transformed, that is, they can be transformed at a faster production rate with lower energy requirements and at the same time such polymers show reduced disturbances of the melt flow. The polyethylenes can be obtained by using the supported catalyst of this invention comprising the at least one metallocene and the at least one component of the transition metal. According to the invention, BMWD polyethylenes can be obtained by use on a support of metallocenes and transition metal components that would have different propagation rate constants and termination for the polymerization of ethylene. Such speed constants are easily determined by those who have ordinary experience in the technique.

The molecular weight distribution of the polyethylenes can also be easily controlled by varying the molar ratios of the metallocene to the transition metal component on the support. Poly6 adjuvants can be used

016 Conventional merizacion such as hydrogen to control the molecular weight of the produced polymer.

The present invention also provides a process for producing reactor mixtures of (co) polyolefins comprising polyethylene and copolyethylene-alpha-olefins. The reactor mixtures are obtained directly during a simple polymerization process, that is, the mixtures of this invention are obtained in a single reactor by polymerizing ethylene and simultaneously copolymerizing ethylene with an alpha-olefin, thus eliminating expensive mixing operations. The process for producing reactor mixtures according to this invention can be used in association with other mixing methods of the prior art. For example, the reactor mixtures produced in a first reactor may be subjected to subsequent mixing in a second stage by the use of the reactors in series.

In order to produce reactor mixtures, the metallocene supported catalyst - transition metal component comprises metallocenes and transition metal compounds having different reactivity ratios.

The reactivity ratios of metallocenes and transition metal components in general are obtained by well-known methods such as, for example, as described in "Linear Method for Determining Monomer Reactivity Ratios in Copolymerization", M, Fineman and SD Ross, J. Polymer Science 5, 259 (1950) or "Copolymerization", FR ,. May and c. Walling, Chem. Rev. 46, 191 (1950) which are incorporated herein in their entirety as a reference. For example, to determine the reactivity ratios, the most widely used copolymerization model was based on the following equations:

In Table I it can be seen that if a mixture comprising HDPE / ethylene-propylene copolymer is desired, 2ZrCl2 and TiCl4 should be selected in ratios of 1 to 10 to 10 to 1, whereas if a mixture comprising LLDPE / ethylene is desired - Propylene should be selected (MeCp) 2ZrCl2 and VCl4 in ratios from 1 to 10 to 10 to 1.

Desirably, the molar ratio of metallocene to transition metal component on the support would be 100 to 1 to 1 to 100, and preferably 10 to 1 to 10. The specific metallocenes selected and their molar ratios depend on the desired molecular composition for the component polymers and on the overall composition desired for the mixture. In general, the component catalyst used in a catalytic mixture of reactor mixture each had r values ​​that are different in order to produce final polymer compositions comprising mixtures of two or more polymers.

TABLE I

Me*

Me*

M2 *

M2 * ^M1

M2 ^Mi

M2 ii i2

2i

K22

M_i^*

M₂^*

M_i^*

M₂^* (1) (2) (3) (4)

<td>Catalyst</td><td>ri</td><td>r2</td>

<td>Cp2Ti = CH₂ Al (Me)₂Cl</td><td> 24</td><td> 0,0085</td>

<td>Cp2TiPh2</td><td> 19,5±1,5</td><td> 0,015±,002</td>

<td>I₂SiCp₂ZrCl₂</td><td> 24±2</td><td> 0,029±,007</td>

<td>Cp2ZrCl2</td><td> 48±2</td><td> 0,015±,003</td>

<td>(MeCp)₂ZrCl₂</td><td> 60</td><td></td>

<td>(I₃Cp) 2ZrCl2</td><td> 250±30</td><td> 0,002±0,001</td>

<td>| Cp2ZrCl | 2O</td><td> 50</td><td> 0,007</td>

<td>TiCl3 (a)</td><td> 15,7</td><td> 0,110</td>

<td>TiCl₄ (to)</td><td> 33,4</td><td> 0,032</td>

<td>VCl3 (a)</td><td> 5,6</td><td> 0,145</td>

<td>VCl₄ (to)</td><td> 7,1</td><td> 0,088</td>

<td>VO (OR) xCl3-x (a)</td><td> 17-28</td><td> -</td>

<td>ZrCl₄ (to)</td><td> 61</td><td> -</td>

where Mi refers to a manomere molecule that is arbitrarily designated i (where i = 1, 2) and Mi^* it refers to a chain of growing polymer to which monomer i has been fixed at the last moment.

The Kij values ​​are the velocity constants for the indicated reactions. In this case, Kii represents the rate at which an ethylene unit is inserted into a growing polymer chain in which the monomer unit previously inserted was also ethylene. The degrees of reactivity are indicated as: ri = kii / ki2 and r2 = k22 / k2i, where kii, ki2, k22 and k2i are the velocity constants for the addition of ethylene (1) or comonoomer (2) to a catalyst site in which the last polymerized monoomer is ethylene (kix) or comonoomer (2) (k2x).

The ratios of ethylene-propylene ri and r2 reactivity for various metallocenes and transition metal components are listed in Table I.

(a) J. Boor, Ziegler - Natta Catalysts and Polymerizations, Academic Press, New York, 1979, p. 577

The cocatalyst system used in accordance with this invention comprises an alumoxane and an orgaonic compound of a metal from Groups 1 to 3 of the Periodic Table.

Examples of the organometallic compounds used in combination with the catalyst component are organic compounds of lithium, magnesium, calcium, zinc, and aluminum. Among other organometallic compounds just mentioned, orgaonic aluminum compounds have proved particularly desirable. The organo-aluminum compounds usable herein are represented by the general formula RnALX3-n (where R denotes an alkyl group or an aryl group having 1 to 18 carbon atoms, X denotes a halogen atom, an alkoxy group or a hydrogen atom, and n denotes a desired number in the range of 1 to 3). Particularly desirable examples of the orgaonic aluminum compounds are aluminum-alkyl compounds such as trialkyl aluminum, dialkyl aluminum monohalide, aluminum dihalide

016 259 monoalkyl, aluminum sesquihalide-alkyl, aluminum monoalkoxide-dialkyl, and aluminum monohydride-dialkyl, having respectively 1 to 18 carbon atoms, preferably 2-6 carbon atoms, and complex mixtures and compounds thereof. Illustrative examples of such organic aluminum compounds are aluminum-trialkyl such as aluminum-trimethyl, aluminum-triethyl, tripropyl aluminum, aluminum-triisobutyl, and trihexyl aluminum; aluminum-dialkyl monohalides such as aluminum chloride-dimethyl, aluminum chloride-diethyl, aluminum bromide

- diethyl, aluminum iodide-diethyl, and aluminum chloride-diisobutyl; aluminum dihalides

- monoalkyl such as methyl aluminum dichloride, aluminum-ethyl dichloride, aluminum-methyl dibromide, ethyl aluminum dibromide, aluminum-ethyl diiodide, and aluminum-isobutyl dichloride; aluminum sesquihalides

- alkyl such as ethyl aluminum sesquichloride; aluminum-dialkyl monoalkoxides such as aluminum-dimethyl methoxide, aluminum-diethyl ethoxide, aluminum-diethyl-ethoxide, aluminum ethoxide-dipropyl, aluminum-ethoxide-diisobutyl, and aluminum-phenoxide diisobutyl, and aluminum-dialkyl hydrides as aluminum hydride - dimethyl, aluminum hydride - diethyl, aluminum hydride - dipropyl, and aluminum hydride - diisobutyl. Among other orgaonic aluminum compounds listed above, aluminum-trialkyl, specifically aluminum-trimethyl, aluminum-triethyl, and aluminum-triisobutyl prove to be particularly desirable. Aluminum-trialkyl can be used in combination with other orgaonic aluminum compounds such as aluminum-diethyl chloride, aluminum-ethyl dichloride, aluminum-ethyl sesquichloride, aluminum ethoxide

- diethyl or aluminum hydride - diethyl, which are commercially available. These other orgaonic aluminum compounds can be used in the form of a complex mixture or compound.

Additionally, it is also usable, an orgaonic aluminum compound having two other aluminum atoms joined together by means of an oxygen atom or nitrogen atom atom. Concrete examples of this organic aluminum compound are (C2H5) 2AlOAl (C2H5) 2, (C4H9) 2AlOAl (C4H9) 2, and (C2H5) 2Al NAl (C2H5) 2.

^|

C2H5

Examples of organic compounds of metals other than aluminum are diethyl magnesium, ethyl magnesium chloride, diethyl zinc and compounds such as LiAl (C2H5) 4 and LiAl (C7H15) 4.

The ratio of alumoxane to the organometallic compound can vary over a wide range and is generally controlled only by the ratio of metallocene to transition metal component. The ratio of alumoxane to metallocene can vary in the range of 1 to 100 moles of aluminum per mole of metallocene metal on the support. The ratio of organometallic compound to transition metal component would generally be in the range of 1 to 100 moles of aluminum per mole of metal of the transition metal component on the support. The alumoxane and the organometallic compound may be mixed in the desired ratio in a suitable hydrocarbon solvent such as isopentane, hexane, or toluene.

The inorgaonic oxide support used in the preparation of the catalyst can be any mixed oxide or oxide consisting of particles as described above that has been chemically or chemically dehydrated so that it is substantially free of adsorbed moisture.

The particle size, the specific surface area, the pore volume, and the number of specific surface hydroxyl groups characteristic of inorgaonic oxide are not critical to their usefulness in the practice of the invention. However, since such characteristics determine the amount of inorganic oxide to be used in the preparation of the catalyst compositions, while affecting the properties of the polymers formed with the aid of the catalyst compositions, these characteristics have to be taken into consideration. frequently when selecting an inorganic oxide for use in a particular aspect of the invention. For example, when the catalyst composition is to be used in a gas phase polymerization process - a type of process in which it is known that the particle size of the polymer can be varied by varying the particle size of the support - the inorganic oxide used in the Preparation of the catalytic composition would be one that had a particle size that was suitable for the production of a polymer that had the desired particle size. In general, optimal results are usually obtained by the use of inorganic oxides having an average particle size in the range of 30 to 600 micrometers, preferably 30 to 100 micrometers; a specific area of ​​50 to 1000 square meters per gram, preferably 100 to 400 square meters per gram; and a pore volume of 0.5 to 3.5 ml per gram, preferably 0.5 to 2 ml per gram.

The polymerization can be conducted by a solution, suspension, or gas phase technique, generally at a temperature in the range of 0 ° - 160 ° C or even higher, and under atmospheric, subatmospheric, or superatmospheric pressure conditions; and can be used if desired conventional polymerization aids, such as hydrogen. It is generally preferred to use the catalytic composition at a concentration such that it provides 0.000001 - 0.005%, most preferably 0.00001 - 0.0003%, by weight of transition metal based on the weight of monomer (s), in the polymerization of ethylene, alone or with one or more higher olefins.

A thick suspension suspension polymerization process can use sub-or super-thermostatic pressures and temperatures in the range of 40-110^°C. In a thick suspension polymerization, a suspension of solid polymer consisting of particles is formed in a liquid polymerization medium to which they are added

016 259 ethylene, alpha-olefin comonomer, hydrogen and catalyst. The liquid used as a polymerization medium may be an alkane or cycloalkane, such as butane, pentane, hexane, or cyclohexane, or an aromatic hydrocarbon, such as toluene, ethylbenzene or xylene. The medium used must be liquid under the conditions of polymerization and relatively inert. Preferably, hexane or toluene is used.

A gas phase polymerization process used superatmospheric pressure and temperatures in the range of 50 120 C. The gas phase polymerization can be carried out in a stirred or fluidized bed of catalyst and product particles in a pressure vessel adapted to allow the separation of product particles and gases that have not reacted. Ethylene, comonoomer, hydrogen and an inert diluent gas such as nitrogen, at thermostatted temperature, can be introduced or recirculated in order to keep the particles at a temperature of 50-120 ^ C. The polymer product can be withdrawn continuously or semi-continuously at a rate such that constant stocks of product are maintained in the reactor. After polymerization and deactivation of the catalyst, the product polymer can be recovered by any suitable means. In commercial practice, the polymer product can be recovered directly from the gas gas reactor, released from residual monoomer with a nitrogen purge, and used without further deactivation or separation of the catalyst. The obtained polymer can be extruded in water and cut into tablets or other appropriate powdered forms. Pigments, anti-oxidants and other additives may be added to the polymer, as is known in the art.

The molecular weight of the polymer product obtained in accordance with this invention may vary over a wide range, from values ​​as low as 500 to 2,000,000 or greater, and preferably from 1,000 to 500,000.

In order to further improve the behavior of the catalyst, modification of the surface of the support material may be desirable. The surface modification is carried out by specifically treating the support material such as silica, alumina or silica-alumina with an organometallic compound having a hydrolytic character. In particular, the surface modifying agents for the support materials comprise the organometallic compounds of the metals of Groups IIA and IIIA of the Periodic Table. Most preferably, the organometallic compounds are selected from organometallic compounds of magnesium and aluminum, and especially between magnesium-and aluminum-alkyls or mixtures thereof, represented by the R-formulas¹MgR² and R¹R²AlR³ in which each of R¹, R² yR³, which may be the same or different, are alkyl groups, aryl groups, cycloalkyl groups, aralkyl groups, alkoxide groups, alkydienyl groups or alkenyl groups. R hydrocarbon groups¹, R² yR³ they can contain between 1 and 20 carbon atoms and preferably 1 to 10 carbon atoms.

The surface modifying action is carried out by adding the organometallic compound in a suitable solvent to a thick suspension of the support material. The contact of the organometallic compound in a suitable solvent with the support is maintained from 30 to 180 minutes and preferably from 60 to 90 minutes at a temperature in the range of 20 to 100 ° C. The diluent used in suspending the support can be any of the solvents used in the solubilization of the organometallic compound, and preferably it is the same.

The amount of surface modifying agent employed in the preparation of the surface modified support material can vary within a wide range. Generally, said amount will be in the range of 1 x 10^-6 moles to approximately 2x10^-3moles of modifying agent per gram of support material. However, larger or smaller amounts may be used.

Illustrative, but not limiting, examples of magnesium compounds that can be suitably employed as a surface modifying agent for the support materials according to the invention are magnesium dialkyl such as diethylmagnesium, dipropylmagnesium, di-isopropyl magnesium, di-n-butylmagnesium. , di-isobutylmagnesium, diamilmagnesium, di-n-octylmagnesium, di-n-hexylmagnesium, di-n-decylmagnesium, and di-n-dodecylmagnesium; dicycloalkylmagnesium, such as dicylohexyl magnesium; diarylmagnesium, such as dibenzylmagnesium, ditolylmagnesium and dixylyl magnesium; alkylalkoxy-magnesiums such as ethyl magnesium ethoxide, and anaologists.

Illustrative, but not limiting, examples of the aluminum compounds that can be suitably employed in accordance with the invention are aluminum trialkyl such as trimethylaluminum, triethylaluminum, tripropyl aluminum, tri-isobutylaluminum, tri-n-hexyl aluminum, and tri-n-octylaluminum. Preferably, the organoaluminum compounds are trimethylaluminum, triisobutylaluminum and triethylaluminum.

Preferably, the surface modifying agents are organomagnesium compounds having 1 to 6 carbon atoms, and most preferably R¹ yR² They are different. Illustrative examples of the preferred magnesium compounds are ethyl-n-propylmagnesium, ethyl-n-butylmagnesium, amyl-n-hexylmagnesium, n-butyl sec-butylmagnesium, n-butyl-n-octylmagnesium and analogs. Mixtures of hydrocarbylmagnesium compounds such as, for example, di-n-butylmagnesium and ethyl n-butylmagnesium can be suitably employed.

Magnesium hydrocarbyl compounds are generally obtained from commercial sources such as mixtures of the magnesium hydrocarbon compound with a small amount of aluminum hydrocarbyl compound. A small amount of aluminum hydrocarbyl is present in order to facilitate solubilization and / or reduce the viscosity of the organomagnesium compound in the hydrocarbon solvent. Solvent

016 The hydrocarbon used useful for the organomagnesium compound can be any of the well-known hydrocarbon liquids, for example, hexane, heptane, octane, decane, dodecane, or mixtures thereof, as well as aromatic hydrocarbons such as benzene, toluene, xylene, etc.

The organomagnesium complex with a smaller amount of aluminum-alkyl can be represented by the formula (R¹MgR²) x (R⁴3Al) and where R¹ yR² are defined as above, R⁴ is defined as R¹ yR² yx is greater than 0. The ratio of ya (y + x) is from 0 to a value less than 1, preferably from 0 to 0.7 and preferably from 0 to 0.1.

Illustrative examples of organomagnesium-organoaluminium complexes are [(n-C4H9) (C2H5) Mg] [(C2H5) 3Al] 0.02, [(n-C4H9) 2Mg] [(C2H5) 3Al] 0.03, [( n-C4H9) 2Mg] [(C2H5) 3Al] 2.0 and [(n-C6H13) 2Mg] [(C2H5) 3Al] 0.01. A suitable magnesium-aluminum complex is MAGALA^R, BEM, manufactured by Texas Alkyls, Inc.

Hydrocarbon soluble organomagnesium materials can be prepared by conventional methods. One such method involves, for example, the addition of an appropriate aluminum-alkyl to a solid dialkylmagnesium in the presence of an inert hydrocarbonate solvent. Organomagnesium-organoaluminum complexes are described, for example, in US Pat. Nos. 3,737,393 and 4,004,071. However, any other method suitable for the preparation of the organometallic compound can be suitably employed.

Since, according to this invention, it is possible to produce a polymer product of high viscosity at a relatively high temperature, the temperature does not constitute a limiting parameter as is the case with the homogeneous metallocene / alumoxane catalysts of the prior art. The catalyst systems described herein, therefore, are suitable for the polymerization of olefins in solution, suspension or gas phase polymerizations and within a wide range of temperatures and pressures. For example, said temperatures may be in the range of -60^°C to 280^°C, and especially in the range of 0^°C to 160^°C. The pressures employed in the process of the present invention are well known, for example, in the range of 1 to 500 atmospheres; however, high pressures of mine can be used.

Polydispersions (molecular weight distribution) expressed as Mw / Mn are typically 2.5 to 100 or greater. The polymers can contain up to 1.0 terminal chain unsaturations per molecule.

The polymers produced by the process of this invention are capable of being transformed into a wide variety of articles, as is known for ethylene homopolymers and copolymers of ethylene and higher alpha-olefins.

In a suspension phase polymerization, the alumoxane cocatalyst in the alumoxane / aluminum-alkyl cocatalyst mixture is preferably methyl-alumoxane, and the aluminum-alkyl cocatalyst in the mixture is preferably Al (CH3) 3 or Al (C2H5) 3. The alumoxane and the aluminum-alkyl cocatalyst are dissolved together in a suitable solvent, typically in an inert hydrocarbonate solvent such as toluene, xylene, and anaologists in a molar concentration of about 5x10^-3M; however, larger or smaller amounts may be used.

The present invention is illustrated by the following examples.

Examples

In the Examples that follow, the alumoxane used was prepared by adding 45.5 grams of ferrous sulfate heptahydrate in 4 increments equally spaced over a period of 2 hours to a round bottom flask of 2 liters of rapidly agitated capacity that It contained 1 liter of a 10% by weight solution of trimethylaluminum (TMA) in hexane. The flask was kept at 50^°C and in nitrogen atmosphere. The methane produced was expelled into the atmosphere continuously. After the addition of ferrous sulfate heptahydrate was completed, the flask was continuously stirred and kept at a temperature of 50^°C for 6 hours. The reaction mixture was cooled to room temperature and allowed to settle. The clear solution was separated from the solids by decantation. The aluminum-containing catalyst prepared according to this procedure contains 65 mole percent of aluminum present as methylalumoxane and 35 mole percent of aluminum present as trimethylaluminum.

Molecular weights were determined in a GPC (Gel Permeation Chromatography) Model No. 150C apparatus of Water's Associates. The measurements were obtained by dissolving polymer samples in hot trichlorobenzene, followed by filtration. GPC operations are performed at 145^°C in trichlorobenzene at a flow rate of 1.0 ml / min using stregel columns from Perkin Elmer, Inc. 300 microliters of a 3.1% solution (300 ml) were injected into trichlorobenzene and the samples were analyzed in duplicate. Integration parameters were obtained with a Hewlett-Packard Data Module.

Fluency index data for polyethylene products was determined at 190^°In accordance with ASTM Method D 1238.

Example 1

Catalyst Preparation Grams of a specific high surface silica (Davison 952^R), dehydrated in a dry nitrogen stream at 600^°C for 5 hours were suspended in suspension with 50 ml of dry toluene at 30^°C under nitrogen in a 250 ml round bottom flask using a magnetic stirrer. A solution of 0.200 grams of bis (cyclopentadienyl) zirconium dichloride and 0.450 grams of TiCl was added dropwise₄ dissolved in 25 ml of toluene was added drop depleted thick suspension of stirred silica. Stirring was continued for 1 hour while the temperature was maintained at 30^°C, at which time the toluene was separated by decantation and the solids were recovered. The solid catalyst is

016 259 washed by stirring and decanting with three 10 ml portions of toluene and dried dry for 4 hours at room temperature. The analysis of the supported catalyst indicated that it contained 1.1 percent by weight of titanium and 0.63 percent by weight of zirconium referred to solid.

Polymerization of ethylene in the gas phase

Polymerization was carried out in the gas phase in a 1-liter autoclave reactor equipped with a vane stirrer, an outer water jacket for temperature control, a septum inlet and a regulated supply of dry nitrogen, ethylene, hydrogen and 1-butene. The reactor, which contained 40.0 grams of ground polystyrene (10 mesh) that was added to aid agitation in the gas phase, dried and thoroughly degassed at 85^°C. 2.0 ml of a solution in hexane of methyl-almoxane and trimethyl-aluminum, which was 0.40 molar in methyl-alumoxane and 0.40 molar in trimethyl-aluminum, were injected through the septum entrance into the interior of the container using a gas-tight syringe. The reactor contents were stirred at 120 rpm a85^°C for 1 minute and at 0 bars of nitrogen pressure (manometric). 60.0 mg of Catalyst A was injected into the reactor and the reactor was pressurized to 13.78 manometric bars with ethylene. Polymerization was continued for 10 minutes while the reaction vessel was maintained at 85^°C and 13.78 manometric bars by constant flow of ethylene. The reaction was interrupted by rapid cooling and expansion. 8.7 grams of polyethylene were recovered. The polyethylene had a weight average molecular weight of 663,000, a number average molecular weight of 5,500, a molecular weight distribution of 121 and a density of 0.960 g / ml. The specific polymerization activity was calculated by dividing the polymer yield by the total weight of transition metal contained in the catalyst, by the time in hours and by the absolute pressure of monomer in atmospheres. For example 1, the specific activity is calculated as follows:

specific activity =

8.7 grams = 0.00104 g Ti + Zr x 0.167 hours x 13.6 = 3700 g / gM. h. atm

Example 2

Polymerization

Using Catalyst A, polymerization was carried out in an identical manner to that of Example 1 with the exception that 13.0 ml of 1-butene was injected after the trimethylaluminum / methylalumoxane solution but before zirconocene.

12.2 grams of polyethylene were recovered. The polyethylene had a weight average molecular weight of 333,000, a number average molecular weight of 5,700, a molecular weight distribution of 58, and a density of 0.920 grams / ml. The specific activity was 5200g / g Mhatm.

Example 3

Polymerization

Polymerization with Catalyst A was carried out in an identical manner to that of Example 1 with the exception that 8.1 millimoles of gaseous hydrogen was injected after the trimethylaluminum / methylalumoxane solution, but before zirconocene. 10.0 grams of polyethylene were recovered. The polyethylene had a weight average molecular weight of 516,000, a number average molecular weight of 4,100, a molecular weight distribution of 126 and a density of 0.960 grams / ml. The specific activity was 4300 g / g Mhatm.

Example 4

Catalyst B Preparation

Catalyst B was prepared ideally to Catalyst A, with the exception that 0.500 mg of di (n-butoxy) titanium dichloride was used as a replacement for TiCl 4, and zirconocene and the titanium compound were dissolved in 10 ml of dry hexane . The analysis of the supported catalyst indicated that it contained 0.90 percent by weight of titanium and 0.63 percent by weight of zirconium.

Polymerization (gas phase)

The polymerization was carried out exactly as in Example 3, with the exception that 50.0 milligrams of Catalyst B were used instead of Catalyst A. 1.4 grams of polyethylene were recovered, which had a weighted average molecular weight of 464,000, a number average molecular weight of 5,900, a molecular weight distribution of 79, and a density of 0.960 g / ml. The specific activity was 800 g / g Mhatm.

Example 5

The polymerization was carried out ideally to that of Example 2, with the exception that 50.0 milligrams of Catalyst B were used as a replacement for Catalyst A. 4.3 grams of polyethylene were recovered, which had a weighted average molecular weight of 825,000, a number average molecular weight of 9,300, a molecular weight distribution of 88, and a density of 0.928 g / ml. The specific activity was 2,500 g / g Mhatm.

016 259