CA1320737C - Alpha-olefin polymerization catalyst system including an advantageous modifier component - Google Patents

Abstract

Abstract of the Disclosure An olefin polymerization catalyst system comprises a solid, hydrocarbon-insoluble, magnesium-containing, tita-nium-containing, electron donor-containing component; an alkyl aluminum compound; and organosilane compound selected from the group consisting of diisobutyldimethoxy-silane, diisopropyldimethoxysilane, t-butyltrimethoxysi-lane and di-t-butyldimethoxysilane, and mixtures thereof.

Description

ALPHA-OL~FIN POLYMERIZATION CATALYST SYSTEM
-INCLUDING AN ADVANTAGEOUS MODIFIER COMPONENT

Background of the Invention This invention relates to olefin polymerization cata-lysts and particularly relates to specific modifier com-pounds useful in a supported alpha-olefin poly~erization catalyst system.
Use of solid, transition metal-based, olefin polymer-ization catalyst components is well known in the art including such solid components supported on a metal oxide, halide or other salt such as widely-described mag-nesium-containin~, titanium halide-based catalyst compo-nents. Also known is incorporating an electron donor compound into the titanium-containin~ component. An olefin polymerization system typically comprises a titani-um-containing compound, an alkylaluminum compound and an electron donor modifier compound. The electron donor mod-ifier used in combination with the alkyl aluminum compound and solid titanium-containing compound is distinct from the electron donor which may be incorporated within the titanium-containing compound. Many classes of electron donors have been disclosed for possible use as electron donor modifiers used during polymeri~a~ion.
One class of such electron donor compounds is organo-silanes. For example in UDS~ Patent 4,540,679, organosi-lanes, especially aromatic silanes are described. Use oforganosilanes as cocatalyst modifiers also is described in Published ~.K. Application 2,111,066 and Published Euro-pean Applications 86,288, 86,471, 86,472 and 86,473.
Other aliphatic and aromatic silanes used in polymeriza-tion catalysts are described in U.S. Patents 4,420,594,4,525,555 and 4,565,798. Typically, it has been found that aliphatic silanes are not as effective as aromatic ~

silanes. It has been found that certain aromatic silanes may produce undesirable products. The invention described herein is a species of aliphatic silane which performs better than other aliphatic silanes as an olefin catalyst electron donor modifier and in many instances as well as, cr better, than aromatic silanes.

Summary of the Invention An olefin polymerization catalyst system comprises a solid, hydrocarbon-insoluble, magnesium-containing, tita-nium-containing, electron donor-containing component; an alkyl aluminum compound; and organosilane compound selected from the group consisting of diisobutyldimethoxy-silane, diisopropyldimethoxysilane, t-butyltrimethoxysi-5 lane and di-t-butyldimethoxysilane, and mixtures thereof.
Brief Description of the Invention The olefin polymerization catalyst system of this invention comprises a supported titanium-containing compo-nent, an alkyl aluminum component and a specific class of aliphatic organosilane compounds. Such class of aliphatic organosilane compounds found most useful in this invention is based on hindered alkylalkoxysilanes and particularly on branched alkyl such as isobutyl and branched butyl (such as isobutyl and t-butyl) methoxy silanes. ~lso, included in this class of organosilane compounds found particularly useful are isopropylalkoxysilanes. Of par-ticular interest is isobutylalkoxysilanes and, partic-ularly, isobutylmethoxysilanes. Of these, diisobutyldimethoxysilane is preferred. Other preferred branched butyl silanes are t-butyltrimethoxysilane and di-t-butyldimethoxysilane. A preferred branched alkyl silane is diisopropyldimethoxysilane. Mixtures of silanes may be used.
The aliphatic silane most useful in this invention is diisobutyldimethoxysilane. This compound may be prepared by methods known to the art such as reacting isobutylene with trichlorosilane in a hydrosilylation reaction to form isobutyltrichlorosilan~. This compound may be reacted with a Grignard-type reagent such as isobutyl magnesium chloride followed by methanolysis with a methoxide to form diisobutyldimethoxysilane.
In another representation of this invention, the silanes useful in this invention may be described as:
RR'Si(OCH3)2 wherein R and R' are isopropyl, isobutyl or t-butyl.
Silanes with mixed alkyl groups, such as isobutylisopropyldimethoxysilane, isobutyl-t-butyldime-thoxysilane and isopropyl-t-butyldimethoxysilane, are included.
The branched alkylalkoxysilanes of this invention, especially diisobutyldimethoxysilane, t-butyltrimethoxysi-lane, di-t-butyldimethoxysilane, and diisopropyldimethoxy-silane show advantageous results when used as a cocatalyst modifier in olefin, particularly propylene, polymerization when used with a supported titanium-containing component.
Such silanes of this invention are particularly advanta-geous used in gas-phase olefin polymerizations.
Other possible hindered alkylmethoxysilanes include diisopentyldimethoxysilane, dineopentyldimethoxysilane, di-t-pentyldimethoxysilane, neopentyltrimethoxysilane, and t-butyltrimethoxysilane. Another group o~ hindered alkyl-methoxysilanes include silacylic compunds with structuressuch as:
~. ~
~ Sl(OCH3)2 or CnH2n Si(oCH3~2 n=4-6 and substituted silacycles having a formula (CyclocnR2n)2si(ocH3)2 wherein R = hydrogen or an alkyl group having 1 to about 5 carbon atoms and n = 4~6, such as:

3 H C ~ ~ ~
Si~OCH )23 ~ Si(OCH3)2 ~ Si(OCH3)2 ~ 3 2 3 H3C CH3 CH3 H3C ~H

Titanium-containing components useful in this invention generally are supported on hydrocarbon-insolu-ble, magnesium-containing compounds in combination with an electron donor compound. Such supported titanium-contain-ing olefin polymerization catalyst component typically is formed by reacting a titanium(IV) halide, an organic elec-tron donor compound and a magnesium-containing compound.
Optionally, such supported titanium-containing reaction product may be further treated or modified by comminution or further chemical treatment with additional electron donor or Lewis acid species.
Suitable magnesium-containing compounds include mag-nesium halides; a react;on product of a magnesium halide such as magnesium chloride or magnesium bromide with an organic compound, such as an alcohol or an organic acid ester, or with an organometallic compound of metals of Groups I-III; magnesium alcoholates; or magnesium alkyls.
One possible magnesium-containing compound, described in U.S. Patent 4,227,370, is based on at least one magne-sium alcoholate which may be pretreated with at least one modifier such as mineral acid or anhydrides of sulfur, organometallic, chalcogenide derivative of hydrogen sul-fide, and organic acids and esters thereof. Such magnesi-um-containing compound may be the pretreatment product of at least one magnesium alcoholate, at least one Group II
or IIIA metal alkyl and, optionally, at least one modifier such as a mineral acid or an anhydride, sulfur, organome-tallic chalcogenide derivatives of hydrogen sulfide, organic acids and organic acid esters. Solid magnesium alkoxide may be milled prior to further treatment. In another catalyst component, magnesium ethoxide may be reacted with an aromatic ester such as phenyl benzoate prior to further treatment with a ~ewis acid.
Another possible catalyst component is described in Canadian Patent Number 1,253,134, issued April 25, 1989, assigned to a common assignee~
.:

The catalyst component described therein is prepared by complexing a magnesium alkyl composition with a specific class of hindered aromatic ester such as ethyl 2,6-dimethylbenzoate followed by reaction with a compatible precipitation agent such as silicon tetrachlo-ride and a suitable titanium(IV) compound in co~bination with an organic electron donor compound in a suitable diluent.
Another possible, and preferable, catalyst component is described in Canadian Pdtent Application Number 539,404, ~iled on June 11, 1987, assigned to a common assignee.

The possible solid catalyst components listed above only are illustrative of many possible solid, magnesium-containin~, titanium halide-based, hydrocarbon-insoluble catalyst components useful in this invention and known to the art. This invention is not limited to a specific sup-ported catalyst component.
Titanium~IV) compounds useful in preparing the solid, titanium-containing catalyst component of invention are titanium halides and haloalcoholates having 1 to about 20 carbon atoms per alcoholate group. Mixtures of titanium compounds can be employed if desired. Preferred titanium compounds are the halides and haloalcoholates having 1 to about 8 carbon atoms per alcoholate group. Examples of such compounds include TiC14, TiBr~, Ti(OCH3)C13, Ti(OC2H5)C13, Ti(OC4Hg)C13~ Ti(OC6H5)C13, Ti(OC6H13)Br3, Ti(OC8H17)C13~ Ti(OCH3)2Br2, Ti(OC2H5)2C12, ( 6 13)2Cl2, Ti(oc8Hl7)2Br2~ Ti(CH3)3Br' Ti(C2H5~3Cl' Ti(OC4Hg)3C1~ Ti(OC6H13)3Br~ and Ti(OC8H17)3Cl- Titanium tetrahalides, particularly titanium tetrachloride (TiC14), are most preferred.

1 3?0737 Organic electron donors useful ln preparation of stereospecific supported titanium-containing catalyst com-ponents many times can be organic compounds containing one or more atoms of oxygen, nitrogen, sulfur, and phosphorus.
Such compounds include organic acids, organic acid esters, alcohols, ethers, aldehydes, ketones, amines, amine oxides, amides, thiols and various phosphorous acid esters and amides, and like. Mixtures of organic electron donors can be used if desired. Specific examples of useful oxy-gen-containing electron donor compounds include organic acids and esters. Useful organic acids contain from 1 to about 20 carbon atoms and 1 to about 4 carboxyl groups.
Preferred titanium component electron donor compounds include esters of aromatic acids. Preferred organic elec-tron donors are Cl-C6 alkyl esters of aromatic mono- and dicarboxylic acids and halogen-, hydroxyl-, oxo-, alkyl-, alkoxy-, aryl-, and aryloxy-substit~ted aromatic mono- and dicarboxylic acids. Among these, the alkyl esters of ben-zoic and halobenzoic acids wherein the alkyl group con-tains 1 to about 6 carbon atoms, such as methyl benzoate,methyl bromobenzoate, ethyl benzoate, ethyl chloroben-zoate, ethyl bromoben~oate, butyl benzoate, isobutyl ben-zoate, hexyl benzoate, and cyclohexyl benzoate, are preferred. Other preferable esters include ethyl p-ani-sate and methyl-p-toluate. An especially preferred aro-matic ester is a dialkylphthalate ester in which the alkyl group contains from about two to about ten carbon atoms.
Examples of preferred phthalate ester are diisobutylphtha-late~ ethylbutylphthalate, diethylphthalate, and di-n-bu-tylphthalate.
The electron donor component used in preparation ofthe solid catalyst component is used in an amount ranging from about 0.001 to about 1.0 mole per gram atom of tita-nium, and preferably from about 0.005 to about 0.~ mole per gram atom. Best results are achieved when this ratio ranges from about 0.01 to about 0.6 mole per gram atom of titanium.

Although not required, the solid reaction product prepared as described herein may be contacted with at least one liquid Lewis acid prior to polymeri~ation. Such Lewis acids useful according to this invention are materi-als which are liquid at treatment temperatures and have a Lewis acidity high enough to remove impurities such as unreacted starting materials and poorly affixed compounds from the surface of the above-described solid reaction product. Preferred Lewis acids include halides of Group III-V metals which are in the liquid state at temperatures up to about 170C. Specific examples of such materials include BC13, AlBr3, TiC14, TiBr4, SiC14, GeC14, SnC14, PC13 and SbC15. Preferable Lewis acids are Ti~14 and SiC14. Mixtures of Lewis acids can be employed if desired. Such Lewis acid may be used in a compatible diluent.
Although not required, the above-described solid reaction product may be washed with an inert liquid hydro-carbon or halogenated hydrocarbon before contact with a Lewis acid. If such a wash is conducted it is preferred to substantially remove the inert liquid prior to contact-ing the washed solid with Lewis acid.
Due to the sensitivity of catalyst components to cat-alyst pois~ns such as water, oxygen, and carbon oxides, the catalyst components are prepared in the substantial absence of such materials. Catalyst poisons can be excluded by carrying out the preparation under an atmos-phere of an inert gas such as nitrogen or argon, or an atmosphere of alpha-olefin. As noted above, purification of any diluent to be employed also aids in removing poi-sons from the preparative system5 As a result of the above-described preparation there is obtained a solid reaction product suitable for use as a catalyst component. Prior to such use, it is desirable to remove incompletely-reacted starting materials from the solid reaction product. This is conveniently accomplished by washing the solid, after separation from any prepara-tive diluent, with a suitable solvent, such as a liquidhydrocarbon or chlorocarbon, preferably within a short time after completion of the preparative reaction because prolonged contact between the catalyst component and unreacted starting materials may adversely affect catalyst component performance.
Although the chemical structure o the catalyst com-ponents described herein is not presently known, the com-ponents preferably contain from about l to about 6 wt.~
titanium, from about lO to about 25 wt.% magnesium, and from about 45 to about 65 wt.% halogen. Preferred cata-lyst components made according to this invention contain from about l.0 to about 3 wt.% titanium, from about 15 to about 21 wt.% magnesium and from about 55 to about 65 wt.%
chlorine.
The titanium-containing catalyst component of this invention may be prepolymerized with an alpha-olefin before use as a polymerization catalyst component. In prepolymerization, catalyst and an organoaluminum compound cocatalyst such as triethylaluminum are contacted with an alpha-olefin such as propylene under polymerization condi-tions, preferably in the presence of a modifier such as a silane and in an inert hydrocarbon such as hexane. Typi-cally, the polymer/catalyst weight ratio of the resulting prepolymerized component is about 0.1:1 to about 20:1.
Prepolymeriæation forms a coat of polymer around catalyst particles which in many instances improves particle mor-phology, activity, stereospecificity, and attrition resistance. A particularly useful prepolymerization pro-cedure is described in U.S. Patent 4,579,836.

The titanium-containing catalyst component of this invention is used in a polymerization catalyst containing a cocatalyst component including a Group II or III metal alkyl and, preferably, an alkyl aluminum compound together with the organosilane component of this invention.

;

_9_ UseEul Group II and IIIA metal alkyls are compounds of the formula MRm wherein M is a Group II or IIIA metal, each R is independently an alkyl radical of 1 to about 20 carbon atoms, and m corresponds to the valence of M.
Examples of useful metals, M, include magnesium, calcium, zinc, cadmium, aluminum, and gallium. Examples of suit-able alkyl radicals, R, include methyl, ethyl, butyl, hexyl, decyl, tetradecyl, and eicosyl.
From the standpoint of catalyst component perform-ance, preferred Group II and IIIA metal alk~ls are those of magnesium, zinc, and aluminum wherein the alkyl radi-cals contain 1 to about 12 carbon atoms. Specific exam-ples of such compounds include Mg(CH3)2, Mg(C2H5)2, Mg(C H )(C4Hg)~ Mg(C4Hg)2~ Mg(C6H13)2~ 9 1~ 25 2 ( 3)2' Zn(c2H5)2' Zn(c4H9)2~ Zn~c4H9)(c8Hl7)~
6 13)2 (C12H25)2~ Al(CH3)3~ Al(C2H5)3~ Al(C H ~
4 9)3' (C6Hl3)3' and Al(C12H25)3- More preferably a magnesium, zinc, or aluminum alkyl containing 1 to about 6 carbon atoms per alkyl radical is used. Alkyl aluminum compounds are most preferred. Best results are achieved through the use of trialkylaluminums containing 1 to about 6 carbon atoms per alkyl radical, and particularly trie-thylaluminum and triisobutylaluminum or a combination thereof.
If desired, metal alkyls having one or more halogen or hydride groups can be employed, such as ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum ses-quichloride, diisobutylaluminum hydride, and the like.
A typical catalyst composition is formed by combining the supported titanium-containing compound described in this invention and an alkyl aluminum compound together with the electron donor silane modifier of this invention.
Typically, useful aluminum-to-titanium atomic ratios in such catalyst formulations are about 10 to about 500 and preferably about 30 to about 300. Preferred aluminum com-pound-to-silane molar ratios are about 1 to about 40.

~lo--Typical aluminum-to-silane compound molar ratios are about 3 to about 30.
The above-described catalysts of this invention are useful in polymerization of alpha-olefins such as ethylene and propylene, and are most useful in stereospecific polymerization of alpha-olefins containing 3 or more carbon atoms such as propylene, butene-1, pentene-l, 4-me-thylpentene-l, and hexene-l, as well as mixtures thereof and mixtures thereof with ethylene. The invented cata-lysts are particularly effective in the stereospecificpolymerization of propylene or mixtures thereof with up to about 20 mole % ethylene or a higher alpha-olefin. Propy-lene homopolymeri~ation is most preferred. According to the invention, highly crystalline polyalpha-olefins are prepared by contacting at least one alpha-olefin with the above-described catalyst compositions under polymerizing conditions. Such conditions include polymerization tem-perature and time, monomer pressure, avoidance of contam-ination of catalyst, choice of polymerization ~edium in slurry processes, the use of additives to control polymer molecular weights, and other conditions well known to per-sons of skill in the art. Slurry-, bulk-, and vapor-phase polymerization processes are contemplated herein.
The amount of catalyst to be employed varies depend-ing on choice of polymerization technique, reactor size,monomer to be polymerized, and other factors known to per-sons of skill in the art, and can be determined on the basis of the examples appearing hereinafter. Typically, catalysts of this invention are used in amounts ranging from about 0.~ to 0.02 milligrams of catalyst to gram of polymer produced.
Irrespective of the polymerization process employed, polymerization should be carried out at temperatures suf-ficiently high to ensure reasonable polymeri~ation rates and avoid unduly long reactor residence times, but not so high as to result in the production of unreasonably high levels of stereorandom products due to excessively rapid polymerization rates. Generally, temperatures range from about 0 to about 120C with about 20 to about 95C being preferred from the standpoint of attaining good catalyst performance and high production rates. More preferably, polymerization according to this invention is carried out at temperatures ranging from about 50 to about 80C.
Alpha-olefin polymerization accordiny to this invention is carried out at monomer pressures of about atmospheric or above. Generally, monomer pressures range from about 20 to about ~00 psi, although in vapor phase polymerizations, monomer pressures should not be below the vapor pressure at the polymerization temperature of the alpha-olefin to be polymerized.
The polymerization time will yenerally range from about 1/2 to several hours in batch processes with corre-sponding average residence times in continuous processes.
Polymerization times ranging from about 1 to about 4 hours are typical in autoclave-type reactions. In slurry proc-esses, the polymerization time can be regulated as desired. Polymerization times ranging from about 1/2 to several hours are generally sufficient in continuous slurry processes.
Diluents suitable for use in slurry polymerization processes include alkanes and cycloalkanes such as pen-tane, hexane, heptane, n-octane; isooctane, cyclohexane, and methylcyclohexane; alkylaromatics such as toluene, xylene, ethylbenzene, isopropylbenzene, ethyl toluene, n-propyl-benzene, diethylbenzenes, and mono- and dialkyl-naphthalenes; halogenated and hydrogenated aromatics such as chlorobenzene, chloronaphthalene, ortho-dichloroben-zene, tetrahydronaphthalene, decahydronaphthalene; high molecular weight liquid paraffins or mixtures thereof, and other well-known diluents. It often is desirable to purify the polymerization medium prior to use, such as by distillation, percolation through molecular sieves, con-tacting with a compound such as an alkylaluminum compound capable of removing trace impurities, or by other suitable means.
Examples of gas-phase polymerization processes in which the catalyst of this invention is useful include both stirred bed reactors and fluidized bed reactor sys-tems and are described in U.S. Patents 3,957,448;
3,965,083i 3,971,768; 3,970,611; ~,129,701; 4,101,289;
3,652,527; and 4,003,712 Typical gas phase olefin polymerization reactor systems comprise a reactor vessel to which olefin monomer and catalyst components can be added and which contain an agitated bed of forming polymer particles. Typically, catalyst components are added together or separately through one or more valve-controlled ports in the reactor vessel. Olefin monomer, typically, is provided to the reactor through a recycle gas system in which unreacted monomer removed as ofE-gas and fresh feed monomer are mixed and injected into the reactor vessel. A quench liquid which can be liquid monomer, can be added to polym-~0 erizing olefin through the recycle gas system in order to control temperature.
Irrespective of polymerization technique, polymeriza-tion is carried out under conditions that exclude oxygen, water, and other materials that act as catalyst poisons.
Also, according to this invention, polymerization can be carried out in the presence of additives to control polymer molecular weights. Hydrogen is typically employed for this purpose in a manner well known to persons of skill in the art.
Although not usually required, upon completion of polymerization, or when it is desired to terminate polym-erization or deactivate the catalysts of this invention, the catalyst can be contacted with water, alcohols, ace-tone, or other suitable catalyst deactivators in a manner known to persons of skill in the art.
The products produced in accordance with the process of this invention are normally solid~ predominantly iso-`.

tactic polyalpha-olefins. Polymer yields are sufficiently high relative to the amount of catalyst employed so that useful products can be obtained without separation of cat-alyst residues. Further, levels of stereorandom by-pro ducts are sufficiently low so that useful products can be obtained without separation thereof. The polymeric prod-ucts produced in the presence of the invented catalysts can be fabricated into useful articles by extrusion, injection molding, and other common techniques.
The invention described herein is illustrated, but not limited, by the following Examples and Comparative Runs.
Examples 1-7 A 1.5 wt.~ suspension of 2 grams of solid, hydrocar-bon-insoluble, magnesium-containing, electron donor-con-taining, titanium chloride-based catalyst component in 160 milliliters of hexane was prepared together with a co-ca-talyst solution containing 3.1 milliliters of 1 molar hexane solution of silane component in 20 milliliters of 1.5 molar triethylaluminum (TEA~ solution in hexane.
A series of propylene polymerization runs was per-formed in a laboratory scale continuous unit based on that described in U. S. Patent 3,965,083. A cylindrical reac-tor vessel of approximately four inches in diameter and 12 inches in length was equipped with three recycle gas noz-zles spaced equidistantly along the bottom of the reactor and three liquid quench nozzles spaced equidistantly along the top of the reactor. The reactor was equipped with an off-gas port for recycling reactor gas through a condenser and back through a recycle line to the recycle nozzles in the reactor. Propylene liquid was used as the quench liquid. During operation polypropylene powder was pro-duced in the reactor bed, flowed over a weir, and dis-charged though a powder discharge system into a secondary closed vessel blanketed with nitrogen. Polymerization temperature and pressure were maintained at 160F ~71C) and 300 psig respectively. The polymer bed was agitated by paddles attached to a longitudinal shaft with in the reactor rotating at about 50 rpm. Hydrogen content in the reactor vapor was maintained at 0.2-0.~ wt.%. Titanium-containing catalyst component was introduced into the reactor through a liquid propylene-flushed catalyst addi-tion nozzle. Mixed co-catalyst (TEA and silane in a hexane solution), maintained at 70F (21C) was added through a co-catalyst addition nozzle flushed with propy-lene. Results are shown in Table I.
Table I summarizes the polymerization results using the polymerization system including a silane modifier of this invention. Also shown are comparative runs using aromatic silanes and other aliphatic silanes as catalyst modifiers. "Yield" (grams of polymer produced per gram of solid catalyst component) was determined by magnesium analysis of the polymer product. "Extractables" were determined by measuring the loss in weight of a dry sample of ground polymer after being extracted in boiling n-hex-ane for four to six hours.

Table I
Gas-Phase Polymerlzation Performance Ex- Cocata- Extrac- Bulk ample lyst Al/Si/Ti Yield tables Density 5 (Run) Modifierl (g/g) (wt.%) (lbs/ft3) 1 IBTMSi 50/5/18~900 1.2 28.6 2 DIBDMSi 50/5/112,1001.3 28.8 3 DIBDMSi 50/8.3/1 12,100 1.0 28.8 10(A) DPDMSi 50/5/111,000103 29.4 (B) DPDMSi 50/5/110,3002.2 28.8 4 IBTMSi 50/5/17,900 2.2 28.9 DIBDMSi 50/5/111,0001.7 28.7 (C) PTMDMSi 50/5/18,300 2.2 28.9 15(D) PTMDMSi 50/3.5/1 7,200 10.7 26.7 (E) NBTMSi 50/5/18,900 1,2 (F) CHTMSi 50/5/15,700 0.7 28.1 (G) CHTMSi 50/5/16,300 0.6 (H) DPDMSi 50/5/19,200 1.0 28.5 20(J) CHMDMSi 50/5/18,800 1A8 28.7 (K) ETMSi 50/5/18,500 1.5 28.3 (L) DEDESi 50/5/16,500 4.2 2804 6 IBTMSi 50/5/17,400 1.0 28.3 7 IBMDMSi 50/5/17,400 2.4 lCocatalyst Modifiers:
IBTMSi = Isobutyltrimethoxysilane DIBDMSi = Diisobutyldimethoxysilane DPDMSi = Diphenyldimethoxysilane PTMDMSi = p-Tolylmethyldimethoxysilane 30 NBTMSi = n-Butyltrimethoxysilane CHTMSi = Cyclohexyltrimethoxysilane IBMDMSi = Isobutylmethyldimethoxysilane CHMDMSi = Cyclohexylmethyldimethoxysilane DEDESi = Diethyldiethoxysilane 35 ETMSi = Ethyltrimethoxysilane _amples 8-10 A catalyst cornponent was prepared according to Exam-ple 21 of Canadian Patent 1,293,242, assigned to a common assignee.
Propylene polymerizations were performed using the contin-uous gas-phase method described in Exa~ples 1-7. Results are shown in Table II.

Table II
10 Gas-Phase Polymerization Performance Ex- Cocata- Extrac- Bulk ample lyst Al/Si/Ti Yield tables Density ( Run ) Modifierl (g/g) (wt.~) (lbs/ft3) 15 8 DIBDMSi 200/20/1 22,100 1.4 28.4 9 IBTMSi50/5/1 19,000 1.3 26.0 IBTMSi5n/3.5/1 21,000 1.7 25.8 (M) DPDMSi100/10/1 19,700 1.3 27.5 (N) ETMSi50/5/1 13,600 1.7 27.0 lCocatalyst Modifiers:
IBTMSi = Isobutyltrimethoxysilane DIBDMSi = Diisobutyldimethoxysilane DPDMSi = Diphenyldimethoxysilane ETMSi = Ethyltrimethoxysilane ., ~ i,, ~ -17-~xamples 11-14 A titanium-containing, magnesium-containing, electron donor-containing catalyst component was prepared according to Example 21 of ~anadian Patent 1,293,242, assigned to a common assignee.

The solid titanium-containing catalyst components prepared above were tested in batch hexane-slurry propy-lene polymerizations. A two-liter ~arr reactor was charged with 650 milliliters of hexane, 150 psig of propy-lene, and 130 ml of hydrogen gas. About 20 milligrams of titanium-containing catalyst component together with a triethylaluminum (TE~)-based cocatalyst system including an organosilane cocatalyst modifier were used in the polymerization test run for two hours at 71C. Specif-ically, a two-liter Parr reactor was charged with 650 mil-liliters of hexane and the temperature was raised to about 43C. The catalyst system was formed from a mixture of 1.0 milliliter of 1.56 molar TEA in hexane, 1.6 millili-ters of 0.1 molar organosilane in hexane and 5 millilitersof additional hexane, into which the solid component was rinsed with about 5 milliliters of hexane. The resulting mixture was flushed into the reactor with about 50 milli-liters of hexane. Following catalyst addition, 130 milli-liters of hydrogen were added, the reactor temperature wasraised to 71C and the reactor was pressuri2ed to 150 psig with propylene. Polymerization continued at this temper-ature and pressure for two hours.

Table III
Slurry-Phase Polymerization Performance Ex- Cocata- Hexane Extrac-ample lyst Al/Si/TiYield Solubles tables 5 (Run) Modifier1 (g/g) (wt.%) (wt.%) ___ _ 11 DIBDMSi 200/10/1 12,600 1.1 2.1 12 IBTMSi 200/10/1 9,200 1.4 2.4 13 IBTMSi 200/10/1 12,300 2.2 10(O) DPDMSi 200/10/1 11,600 0.9 2.0 14 IBMDMSi 200/10/1 10,950 2~0 2.7 (P) ATMSi 200/10/1 9,200 2.1 2.3 (Q) CHTMSi 200/10/1 10,700 1.0 2.1 (R) TMSi 200/10/1 5,000 3.2 3.5 lCocatalyst Modifiers:
IBTMSi = Isobutyltrimethoxysilane DIBDMSi = Diisobutyldimethoxysilane DPDMSi = Diphenyldimethoxysilane ATMSi = Amyltrimethoxysilane 20 CHTMSi = Cyclohexyltrimethoxysilane TMSi = tetramethoxysilane -19~

Examples 15-21 - Comparative Runs AA--QQ
A series of polymerization test runs were performed as described in Examples 11-14 but using different organo-silane compounds as a modifier component. The Al/Si/Ti ratio was 200/20/1 in all runs. That the results are shown in the Table IV.

Table IV
Slurry-Phase Polymerization Performance Ex- Cocata- Hexane Extrac- Melt ample lyst Yield Solubles tables Flow Rate (Run) Modifier1 (g/g) (wto%) (wt~%) ~g/lOmin) DIBDMSi~ 13,500 0.8 1.5 2.0 16 TBTMSi3 11,500 0.6 0.8 1.5 1017 TBTMSi3 13,300 0.6 1.3 0.7 18 DIPDMSi3 12,000 0.6 1.1 2.5 19 DTBDMSi3 15,800 0.6 1.6 0.4 DTBDMSi5 20,000 0.9 1.8 1.4 21 DTBDMSi6 19,000 1.0 1.6 loO
15(AA) DIBDESi 10,000 2.2 3.3 3.4 (BB) DIBDESi 10,600 2.4 2.8 9-3 (CC) DIBDIPSi ~7,500 >12 _4 (DD) DIBDIPSi ~6,500 ~25 _4 (EE) DIBDIBSi 67700 >43 4.64 15.2 20(FF) IBTESi9,800 103 2~3 (GG) IBTESi8,900 2.3 2.0 (HHJ IBTESi12,200 2.7 4.0 6.5 (JJ) IBTESi12,000 3.1 3.2 5.7 (KK) IBTIBSi 7,600 >24 ~.24 13.9 25(LL~ IBTIBSi 9,600 >32 6.14 9.1 (MM) SBTESi10,400 2.4 2.6 5.2 (NN) SBTESi3 11,200 2.0 2.6 4-9 (00) DNBDMSi 10,600 1.7 2.7 6.0 (PP) IBMDMSi 10,800 1.7 1.8 4.6 30(QQ) DCHDMSi3 10,000 0.9 2~ 3 Cocatalyst Modifiers:
DIBDMSi = Diisobutyldimethoxysilane TBTMSi = t-Butyltrimethoxysilane DIPDMSi = Diisopropyldimethoxysilane DTBDMSi = Di-t~Butyldimethoxysilane DIBDESi = Diisobutyldiethoxysilane DIBDIPSi = Diisobutyldiisopentoxysilane DIBDIBSi = Diisobutyldiisobutoxysilane IBTESi = Isobutyltriethoxysilane IBTIBSi = Isobutyltriisobutoxysilane SBTESi = s-Butyltriethoxysilane DNBDMSi = Di-n-butyldimethoxysilane IBMDMSi = Isobutylmethyldimethoxysilane DCHDMSi = Dicyclohexyldimethoxysilane 2Results listed for DIBDMSi are an average of 13 separate test runs.
3Results are an average of 2 separate test runs.
4Polymer could not be filtered.
524 mmole of H2 used; average of 2 test runs.
616 mmole of H2 used; average of 3 test runs.

Examples 22-24 A titanium-containing, magnesiurn-containing, electron donor-containing catalyst component was prepared as described in Canadian Patent 1,293,242, assigned to a common assignee. Propylene polymerizations were performed using the continuous gas-phase method described in Exam-ples 1-7 using diisobutyldimethoxysilane and diisobutyldi-methoxysilane as modiiers. Results are shown in Table V.

Tab]e V
Gas-Phase Polymerization Performance Ex- Cocata- Extrac- Bulk ~FR
ample lyst Al/Si/Ti Yield tables Density (g/
15 (Run) ModiEierl (g/g) (wt-3) (lbs/ft3) min) 22 DIBDMSi 100/17/1 20,000 1.1 25.7 3.9 23 DIPDMSi lO0/17/l 20,000 l.0 25.5 2.0 24 DIPDMSi lO0/8/l 21,000 0.9 26.2 2.3 lCocatalyst Modifiers:
DlBDMSi = Diisobutyldimethoxysilane DIPDMSi = Diisopropyldimethoxysilane

Claims (14)

1. An olefin polymerization catalyst system compris-ing a solid, hydrocarbon-insoluble, magnesium-containing, titanium-containing, electron donor-containing component;
an alkyl aluminum compound; and organosilane compound selected from the group consisting of diisobutyldimethoxy-silane, diisopropyldimethoxysilane, t-butyltrimethoxysi-lane and di-t-butyldimethoxysilane.

2. The catalyst system of claim 1 wherein the orga-nosilane compound is diisobutyldimethoxysilane.

3. The catalyst system of claim 1 wherein the orga-nosilane compound is diisopropyldimethoxysilane.

4. The catalyst system of claim 1 wherein the orga-nosilane compound is t-butyltrimethoxysilane or di-t-bu-tyldimethoxysilane.

5. The catalyst system of claim 1 wherein the orga-nosilane compound is t-butyltrimethoxysilane.

6. The catalyst system of claim 1 wherein the orga-nosilane compound is di-t-butyldimethoxysilane.

7. An olefin polymerization catalyst system compris-ing a solid, hydrocarbon-insoluble, magnesium-containing, titanium-containing, electron donor-containing component;
triethylaluminum; and organosilane compound selected from the group consisting of diisobutyldimethoxysilane, diiso-propyldimethoxysilane, t-butyltrimethoxysilane and di-t-butyldimethoxysilane.

8. The catalyst system of claim 7 wherein the orga-nosilane compound is diisobutyldimethoxysilane.

9. The catalyst system of claim 7 wherein the orga-nosilane compound is diisopropyldimethoxysilane.

10. The catalyst system of claim 7 wherein the orga-nosilane compound is t-butyltrimethoxysilane or di-t-bu-tyldimethoxysilane.

11 The catalyst system of claim 7 wherein the orga-nosilane compound is t-butyltrimethoxysilane.

12. The catalyst system of claim 7 wherein the orga-nosilane compound is di-t-butyldimethoxysilane.

13. An olefin polymerization catalyst system compris-ing a solid, hydrocarbon-insoluble magnesium-containing, titanium-containing, electron donor-containing component;
an alkyl aluminum compound; and organosilane compound having a structure:
RR'Si(OCH3)2 wherein R and R' are isobutyl-, isopropyl or t-butyl-groups.

14. An olefin polymerization catalyst system compris-ing a solid, hydrocarbon-insoluble, magnesium-containing, titanium-containing, electron donor-containing component;
an alkyl aluminum compound; and organosilane compound selected from the group consisting of isobutyltrimethoxy-silane and mixtures of isobutyltrimethoxysilane and diiso-butyldimethoxysilane.