CA2171103C - Gas phase polymerization of olefins - Google Patents

Abstract

Novel gas phase fluidized bed process for producing ethylene polymers having improved processability. Multiple reactors in series or parallel may be used to produce in-situ blended polymers. Each reactor can separately have a constrained geometry catalyst or a conventional Ziegler-Natta catalyst as needed for obtaining in-situ blended polymer with the desired properties as long as there is a constrained geometry catalyst in at least one reactor. Olefin polymers can be produced according to this invention having low susceptibility to melt fracture, even under high shear stress conditions.

Description

~'~ ~''m~Qd~ P~~'lYTS94I10621 GAS PHASE PLYEIZATIGLFI S
This invention relates to a gas phase ffuidized bed process for producing olefin polymers, particularly ethylene polymers, having improved processability. These polymers include olefin polymers having low susceptibility to melt fracture, even under high shear stress conditions.
The discovery of the fluidized bed process for the production of linear olefin polymers provided a means for producing these diverse and widely used polymers with a drastic reduction in capital investment and a dramatic reduction in energy requirements as compared to then conventional processes.
To be commercially useful in a gas phase process, such as the fluid bed processes of U.S. Pat. Nos. 3,709,853; 4,003,712 and 4,011,382; Canadian Pat. No. 991,798 and Selgian Pat. No. 839,380, the catalyst employed must be a highly active catalyst. Typically, levels of productivity reach from 50,000 to 1,000,000 pounds of polymer or more per pound of primary metal in the catalyst. High productivity in the gas phase processes is desired to avoid the expense of catalyst residue removal procedures. Thus, the catalyst residue in th~~ polymer must be small enough that it can be left in the polymer without causing any undue problems to either the resin manufacturer, or to a party fabricating articles from the resin, or to an ultimate user of such fabricated articles. lNhere a high activity catalyst is successfully used in such fluid bed processes, the transition metal content of the resin is on the order of <_ 20 parts per million (ppm) of primary metal at a productivity level of _> 50,000 pounds of polymer per pound of metal. Lovv catalyst residue contents are also important in heterogeneous catalysts comprising chlorine containing materials such as the titanium, magnesium and/or aluminum chloride complexes used in some so-called Ziegler or Ziegler-Natta type catalysts. lJse of these heterogeneous catalysts results in a polymerization reaction product which is a complex mixture of polymers, ~rith a relatively wide distribution of molecular weights.
This wide distribution of molecular weights has an effect (generally detrimental) on the physical properties of the polymeric materials, e.g.
decreased tensile strength, dart impact.
_1_ The molecular weight distribution (MWD), or poiydispersity, is a known variable in polymers which is described as the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (i.e., Mw/Mn), parameters which can be determined directly, for example by gel permeation chromatography techniques. The I ~ p/12 ratio, as described in ASTM D-1238, can be an indicator of the MWD in conventional heterogeneous ethylene polymers. The I~p/12 ratio is also an indicator of the-shear sensitivity and processibility for ethylene polymers. Low density polyethylenes (LDPE) typically have a higher 11 p/12 ratio than linear low density polyethylenes (LLDPE) or ultra low density linear polyethylenes (ULDPE) and are easier to melt process in fabrication equipment ~at comparable 12 values.
Ethylene polymers having a narrow MWD and homogeneous comonomer distribution are known. These polymers can be produced using homogeneous 'single site" catalysts, such as metallocene or vanadium catalysts. Whsle the physical properties of these polymers are generally superior to heterogeneous polymers, they are often difficult to process with conventional melt fabrication equipment. The problems are manifested, for example, in their lack of ability to sustain a bubble it a blow's film process, and by a 'sag' when evaluated in blow molding processes. In addition, the melt fracture surface properties of these polymers are often unacceptable at high extrusion rates, a feature that makes them less desirable for use in equipment operating at current high speed extrusion (i:e., production) rates. Extruders often exhibit increased power consumption due to the low shear sensitivity of these polymers.
Use of the catalyst systems described in U.S. Patent Nos. 5,374,696 and 5,453,410, results in the production of unique polymers having the properties as taught in U.S. Patent Nos. 5,272,236 and 5,278,272. These polymers are substantially linear olefin polymers which are characterized as having a critical shear rate at the onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of W~ 9~J07942 PC'd'/i1S94I10621 surface melt fracture of a linear olefin polymer having about the same L2 and Mw/n.
There is a need for a gas phase olefin polymerization catalyst that can be used more efficiently and effectively to polymerize or copolymerize ethylene with higher alpha-olefins, e.g. alpha-olefins having 3 to 20 carbon atoms. In practice, the commercial copolymers are made rising monomers having only 3 to carbon atoms (i.e., propylene, 1-butane, 1-hexane, 1-octane and 4-methyl-1-pentane) because of the low rate of reactivity and incorporation of the alpha olefins with larger carbon chains and, for gas phase processes, because of the lower concentration possible in the reactor for alpha-olefins with larger carbon chains. The traditional Ziegler catalysts are not particularly efficient or efv~ective in incorporating the higher alpha-olefin comonomers into the polymer.
The rate of reaction for the ethylene monomer is much greater than the rate of reaction for the higher alpha-olefin monomers in the copolymerization reaction using traditional multi-site Ziegler catalysts. Accordingly, due to the lower reaction rate of incorporating the longer chain comonomer into the growing polymer chain, the copolymer fractions containing the higher alpha-olefin comonomers are generally the lower molecular weight fraction having limited desirable physical properties. These factors also contribute to polymer particles sticking together or agglomerating in the gas phase process.
Even in the most current olefin copolymerization systems, there is still a need for a gas phase olefin polymerization catalyst which is able to incorporate efficiently larger amounts of higher alpha-olefins into a copolymer chain and give a polymeric product which has a narrow molecular weight distribution and is more homogeneous with respect to comonomer distribution than otherwise would be achieved using a Ziegler catalyst under comparable conditions. The properties and advantages of linear homogeneous copolymers are described in IJ.S. Patent 3,fi45,992.
Canich et al. teach in IJ.S. Patent 5,057,4I'5, U.S. Patent 5,026,798, and LJ. S. Patent 5,096,867 a supported catalyst system which includes an inert support material, a Group IV B metal component and an alumoxane component for use in the production of high molecular weight poiyolefins.

~'~ 9~1~79~2 ~Wf'lli(J~9~/~~~~g a: er .. , J t.
Thorn is also a need for a gas phase process to produce more homogeneous narrow molecular weight distribution pofyolefins ~I~~ of ~.5-2.5)9 that have improved processability such as provided by substantially linear olefin polymers.
A fluidized bed gas phase process for the production of an ethylene Another aspect of this invention is a process for in situ blending of polymers oomprising continuously contacting, under polymerization condBt~onso a mixture of ethylene and at feast one or more ~,-olefin or diolefin in at least two fluidized bed reactors connected in series, with a catalyst with the polyrneri~ation conditions being such that an ethylene copolyr~aer having a higher melt index is formed in at least one reactor and an ethylene copolymer having a lower rraelt index is formed in at least one other reactor with the provisos that:
(a) in a reactor in ~rhich the lower melt index copolymer is made:
(1 ) said alpha-olefin or diolefin is present in a ratio of about ~.~ t '~o about 3.5 total moles of alpha-olefin and diofefin per mole of ethylene; and ~'~ 95107942 PC'1'//1JS94I10621 (2) hydrogen is present in a ratio of about 0 to about 0.3 mole of hydrogen per mole of ethylene;
(b) in a reactor in which higher melt index copolymer is made:
(1 ) said alpha-olefin or diolefin is present in a ratio of about 0.005 to about 3.0 total moles of alpha-olefin and diolefir~ per mole of ethylene; and (2) hydrogen is present in a ratio of about 0.05 to about 2 moles of hydrogen per mole of ethylene, (c) the mixture of catalyst and ethylene copolymer formed in one reactor in the series is transferred to an immediately succE~eding reactor in the series.
(d) the catalyst system comprises a constrained geometry catalyst and optionally, another catalyst.
(e) catalyst may be optionally added to each reactor in the series9 provided that catalyst is added to at least the first reactor in the series;
Yet another aspect of this invention is the process for in situ blending of polymers comprising continuously contacting, under polymerization conditions, a mixture of ethylene and at least one ~,-olefin andlor diolefin in at least two fluidized bed reactors connected in parallel, with a catalyst with the polymerization conditions being such that an ethylene copolymer having a higher melt index is formed in at least one reactor and an ethylene copolymer having a lower melt index is formed in at least one other reactor with the provisos that:
(a) in a reactor in which the lower melt index copolymer is made:
(1 ) said alpha-olefin and/or diolefin is present in a ratio of about 0.01 to ak~out 3.5 total moles of alpha-olefin or diolefin per mole of ethylene; and _5_ (2) hydrogen is present in a ratio of about 0 to about 0.3 mole of hydrogen per mole of ethylene;
(b) in a reactor in which higher melt index copolymer is made:
(1) said alpha-olefin or diolefin is present in a ratio of about 0.005 to about 3.0 total moles of alpha-olefin and diolefin per mole of ethylene; and (2) hydrogen is present in a ratio of about 0.05 to about 2 moles of hydrogen per mole of ethylene, (c) the catalyst system comprises a constrained geometry catalyst and optionally, another catalyst.
In all embodiments of the invention, the constrained geometry catalyst is used in at least one of the reactors.
An advantage of this invention is that at least one constrained geometry catalyst can be used alone or in conjunction with at least one other catalyst in reactors operated in series or parallel.
Yet another advantage is that due to the ability of supported constrained geometry catalysts to incorporate efficiently longer chain higher alpha-olefin comonomers into a polymer, the range of copolymer densities which can be made in a conventional gas phase reactor without having to condense the recycle stream is dramatically increased.
In one aspect, the invention provides a fluidized bed gas phase process for the production of an ethylene polymer comprising reacting by contacting under polymerization conditions ethylene or ethylene and at least one of a copolymerizable alpha-olefin or diolefin in the presence of a catalyst characterized by an absence of an activating amount of alumoxane, comprising: A) 1) a metal complex corresponding to the general formula:
~Z\
L \Y
'M' ~X~)q ~n or dimers thereof, wherein: M is a Group 4 metal in the +3 or +4 formal oxidation state; L is a group containing a cyclic, delocalized, aromatic, anionic, ~ system and the inertly substituted derivatives thereof through which the L
group is bound to M, and which L group is also bound to Z, said L group containing up to 60 non-hydrogen atoms; Z is a moiety covalently bound to both L and Y, comprising boron, or a member of Group 14 of the Periodic Table of the Elements, said moiety having up to 60 non-hydrogen atoms; Y
is a moiety comprising nitrogen, phosphorus, sulfur or oxygen through which Y is covalently bound to both Z and M, said moiety having up to 25 non-hydrogen atoms; X' independently each occurrence is a Lewis base containing up to 40 non-hydrogen atoms; X independently each occurrence is a monovalent anionic moiety having up to 20 non-hydrogen atoms, provided however that neither X is an aromatic group that is ~-bonded to M, optionally, two X groups may be covalently bound together forming a divalent dianionic moiety having both valences bound to M, or further optionally one or more X and one X' group may be bonded together thereby forming a moiety that is both covalently bound to M and coordinated thereto by means of Lewis base functionality; q is a number from 0 to 1; and n is 1 or 2 depending on the formal oxidation state of M; 2) an -6a-activating cocatalyst selected from the group consisting of (i) C1-C3o hydrocarbyl substituted boranes and halogenated derivatives thereof, and (ii) borates of the general formula:
[L*-H]+[BQ4]
wherein: L* is a neutral Lewis base; [L*-H]+ is a Bronsted acid; B is boron in a valence state of 3; and Q is a hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-, fluorinated hydrocarbyloxy-, or fluorinated silylhydrocarbyl-group of up to 20 non-hydrogen atoms, with the proviso that in not more than one occasion is Q
hydrocarbyl; and 3) an inorganic oxide support which is substantially free of adsorbed moisture or surface hydroxyls; or B) the complex of the above formula is electrochemically oxidized to an active catalyst under electrolysis conditions in the presence of a supporting electrolyte comprising a noncoordinating, inert anion.
In a further specific aspect, the invention provides a fluidized bed gas phase process for the production of an ethylene polymer comprising reacting by contacting under polymerization conditions ethylene or ethylene and at least one of a copolymerizable alpha-olefin or diolefin in the presence of a catalyst characterized by an absence of an activating amount of alumoxane, comprising:
A) 1) a metal complex corresponding to the general formula:
R' Y
R~ (I) ~~'~n R' -6b-CA 02'171103 2004-11-04 wherein: R' each occurrence is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said R' having up to 20 non-hydrogen atoms, and optionally, two R' groups (where R' is not hydrogen, halo or cyano) together form a divalent derivative thereof connected to adjacent positions of the cyclopentadienyl ring to form a fused ring structure; Y is -0-, -S-, -NR*-, -PR*-; Z is SiR*2, CR*2, SiR*2SiR*2, CR*zCR*2, CR*=CR*, CR*zSiR*2, or GeR*2; wherein: R* each occurrence is independently hydrogen, or a member selected from the group consisting of hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, said R*
having up to 20 non-hydrogen atoms, and optionally, two R*
groups from Z (when R* is not hydrogen), or an R* group from Z and an R* group from Y form a ring system; M is titanium or zirconium in the +3 or +4 formal oxidation state; X is chloro, hydrocarbyl, hydrocarbyloxy, silyl or N,N-dialkylamino substituted hydrocarbyl group; and n is 1 or 2; 2) an activating cocatalyst selected from the group consisting of (i) C1-C3o hydrocarbyl substituted boranes and halogenated derivatives thereof, and (ii) borates of the general formula:
[L*-H] + [BQ4]
wherein: L* is a neutral Lewis base; [L*-H]+ is a Bronsted acid; B is boron in a valence state of 3; and Q is a hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-, fluorinated hydrocarbyloxy-, or fluorinated silylhydrocarbyl-group of up to 20 non-hydrogen atoms, with the proviso that in not more than one occasion is Q
hydrocarbyl; and 3) an inorganic oxide support which is g~,~hgt~_n_ti_al l_ 1r frees pf arlcprbarl rrtni_gtpre pr cprfurc hydroxyls; or B) the complex of formula (I) is electrochemically oxidized to an active catalyst under -6c-electrolysis conditions in the presence of a supporting electrolyte comprising a noncoordinating, inert anion.
Figure 1 graphically displays the structural characteristics of a traditional heterogeneous Ziegler polymerized LLDPE copolymer, a highly branched high pressure free radical LDPE, a homogeneously branched linear copolymer, and a substantially linear ethylene alpha-olefin copolymer.
The Ethylene Copolymers All reference to the Periodic Table of the Elements herein shall refer to the Periodic Table of the Elements, published and copyrighted by CRC Press, Inc., 1989. Also, any reference to a Group or Groups shall be to the Group or -6d-W~ 95/07942 PC'T/iJS94110621 Groups as reflected in this Periodic Table of the Elements using the IlJPAC
system for numbering Groups.
Monomers usefully polymerized according to the present invention include, for example, ethylenically unsaturated monomers, conjugated or nonconjugated dienes, polyenes, etc. Preferred monomers include the C2-C10 ~-olefins especially ethylene, propane, isobutylene, 1-butane, 1-hexane, 4-methyl-1-pentane, and 1-octane. ~ther preferred monomers include styrene, halo- or alkyl substituted styrenes, tetrafluoroethylene, vinylbenzocyclobutene, 1,4-hexadiene, 1,5-hexadiene, 1,7-octadieneo 4-vinylcyclohexene, and vinylcyclohexane, 2,5-norbornadiene, ethylidenenorbornene, 1,3-pentadiene, 1,4-pentadiene, 1,3-butadiene, isoprene and nahhthenics (e.g., cyclopentene, cyclohexene and cyclooctene).
Throughout this disclosure, °'melt index" cr "12°' is measured in accordance with ASTM D-1238 (190°C/2.16 kg)9 .'110" is measured in accordance with ASTM D-1238 (190°C/10 kg). I=or linear polyolefins, especially linear polyethylene, it is well known that as Mw/Mn increases, also increases. Vllith the ethylene or ethylene/~,~~olefin or diene substantially iir~~ear olefin polymers that can be made by this invention, the 110/12 may be increased without increasing Mw/Mn. The melt index for the ethylene or ethyfene/~,-olefin substantially linear olefin polymers used herein is generally from about 0.01 grams/10 minutes (g/10 min) to about 1000 g/10 min, preferably from about 0.01 g/10 min to about 100 g/10 min, and especially from about 0.01 g/10 min to about 10 g/10 min.
_7-The copolymers have a 110/12 melt flow ratio of about >_ 6 to _< 18, and preferably of about ? 7 to <_ 14.
The whole interpolymer product samples and the individual interpolymer samples are analyzed by gel permeation chromatography (GPC) on a Waters 150C high temperature chromatographic unit equipped with three mixed porosity bed columns (available from Polymer Laboratories); operating at a system temperature of 140C. The solvent is 1,2,4-trichlorobenzene, from which 0.3 percent by weight solutions of the samples are prepared for injection. The flow rate is 1.0 milliliters/minute and the injection size is 200 microliters.
The molecular weight determination is deduced by using narrow molecular weight. distribution polystyrene standards (from Polymer Laboratories) in conjunction with their elution volumes. The equivalent polyethylene molecular weights are determined by using appropriate Mark-Houwink coefficients for polyethylene and polystyrene (as described by Williams and Word in Journal of Po_lyrmer Science, Pol3rmer Letters, Vol. 6, (621 ) 1968) to derive the following equation:
Mpolyethylene = a * (Mpolystyrene)b.
In this equation, a = 0.4316 and b = 1Ø Weight average molecular weight, Mw, is calculated in the usual manner according to the following formula: Mw =
E wi* Mi, where w1 and Mi are the weight fraction and molecular weight, respectively, of the ith fraction eluting from the GPC column.
The molecular weight distribution (Mw/Mn) for the ethylene polymers of this invention is generally less than about 5, preferably from about 1.5 to about 2.6, and especially from about 1.7 to about 2.3.
The density of the polymers in the present invention is measured in accordance with ASTM D-792 and is generally from about 0.85 g/cm3 to about 0.96 g/cm3, preferably from about 0.865 g/cm3 to about 0.96 g/cm3. The density of the copolymer, at a given melt index level for the copolymer, is primarily regulated by the amount of the comonomer which is copolymerized With tl~e et hylene. lil tile abS2f7i,e Of ti i~ LW 1 ivi WnTicr , ii i2 Bti iy~2ii2 wOUid _g.

~ 95107942 ~~ThLTS94I1062I
Tl~e term °'linear" as used herein means that the ethylene polymer does not have long chain branching. That is, the polymer chains comprising the bulk linear ethylene polymer have an absence of long chain branching, as for em~ample the traditional linear low density polyethylene polymers or linear high density polyethylene polymers made using Ziegler polymerization processes (e.g., l9SP 4,0?8,698 (Anderson et al.)), sometimes called heterogeneous polymers. The term "linear" does not refer to bulk high pressure branched polyethylene, ethylene/vinyl acetate copalymers, or ethylene/vinyl alcohol o~jpolymers uvhich are known to those skilled in the art to have numerous long chain branches. The term "linear'° also refers to polymers made using uniform branching distribution polymerization processes., sometimes called homogeneous polymers, including narrow IiIIVV~ (e.g. about 2) made using single site catalysts. Such uniformly branched or homogeneous polymers include those made as described in IJSP 3,845,992 (Elston) and those made using so-called single site catalysts in a batch reactor having relatively high ethylene concentrations (as described in IJ.S. Patent 5,026,798 (Canich) or in l~.S. Patent 5,055,438 (Canich)) or those made using constrained geometry cG~talysts in a batch reactor also having relatively high olefin concentrations (as described in ~J.S. Patent 5,064,802 (Stevens et al.) or in EP 0 416 815 A2 (Stevens et al.)). The uniformly branched/homogeneous polymers are those polymers in which the comonomer is randomly distributed within a given interpolymer molecule or chain, and wherein suk~stantially al! of the interpolymer molecules have the same ethylene/'comonomer ratio within that ini:erpolymer, but these polymers, too, have an absence of long chain _g_ W~ 95107~d~ 3~~(C'~'l~J~~~/~~fa2;f r.: ~
,! a. ~ t.a branching, es, for example, Exxon Chemical has taught in their February 9992 ~appi J~~rnel paper (pp 99°903).
properties).
Long chain branching {LCS) is defined herein as a chain length of at least one {9) carbon less than the number of carbons in the comonomer, whereas short chain branching {SCS) is defined herein as a chain length of the same number of carbons in the residue of the comonomer after it is incorporated into the polymer molecule backbone. for example, en ethylene/9 moctene substantially linear polymer has backbones with long chain branches of at least seven (7) carbons in length, but it also has short chain branches of only six (6) carbons in length.
Long chain branching can be distinguished from short chain branching by using 13C nuclear magnetic resonance (NMR) spectroscopy and to a limited extent, e.g. for ethylene homopolymers, it can be quantified using the method of Randall (Rev. MacromoLChem. Phys., C29 (2&3), p. 285-297), However as a practical matter, current 13C nuclear magnetic resonance spectroscopy cannot determine the length of a long chain branch in excess of six (6) carbon atoms and as such, this analytical technique cannot distinguish between a seven (7) carbon branch and a seventy (70) carbon branch. The long chain branch can be as long as about the same length as the length of the polymer backbone.
U.S. Patent 4,500,648, teaches that long chain branching frequency (LCB) can be represented by the equation LCB=b/Mw wherein b is the weight average number of long chain branches per molecule and Mw is the weight average molecular weight. The molecular weight averages and the long chain branching characteristics are determined by gel permeation chromatography and intrinsic viscosity methods.
The SCBDI (Short Chain Branch Distribution Index) or CDBI
(Composition Distribution Branch Index) is defined as the weight percent of the polymer molecules having a comonomer content within 50 percent of the median total molar comonomer content. The CDBI of a polymer is readily calculated from data obtained from techniques known in the art, such as, for example, temperature rising elution fractionation (abbreviated herein as "TREF") as described, for example, in Wild et al, Journal of Polymer Science, Poly. Phys. Ed., Vol. 20, p. 441 (1982), or as described in U.S. Patent 4,798;081. The SCBDI or CDBI for the substantially linear ethylene polymers of the present invention is typically greater than about 30 percent, preferably greater than about 50 percent, more preferably greater than about 80 percent, and most preferably greater than about 90 percent.
"Melt tension" is measured by a specially designed pulley transducer in :,cnjunctic~~ With the melt indexes. Melt tensie~ is the load that the extrudate or filament exerts while passing over the pulley onto a two inch drum that is rotating at the standard speed of 30 rpm. The melt tension measurement is similar to the "Melt Tension Tester° made by Toyoseiki and is described by John Deaiy in 'Rheometers for Molten Plastics", published by Van Nostrand Reinhold Co. (1982) on page 250-251. The melt tension of the substantially linear polymers of this invention is also surprisingly good, e.g., as high as about 2 grams or more. For the substantially linear ethylene interpolymers of this invention, especially those having a very narrow molecular weight distribution (i.e., M~Mn from 1.5 to 2.5), the melt tension is typically at least about 5 percent; and can be as much as about 60 percent, greater than the melt tension of a conventional linear ethylene interpolymer having a melt index, polydispersity and density each within ten percent of the substantially linear ethylene polymer.
A unique characteristic of the substantially linear polymer is a highly unexpected flow property where the 110/12 value is essentially independent of polydispersity index (i.e., M~Mn). This is contrasted with conventional Ziegler polymerized heterogeneous polyethylene resins and with conventional single site catalyst polymerized homogeneous polyethylene resins having rheological properties such that as the polydispersity index increases; the 110/12 value also increases.
Processing Index Determination The 'rheological processing index" (PI) is the apparent viscosity (in kpoise) of a polymer and is measured by a gas extrusion rheometer (GER).
The GER is described by M. Shida, R.N. Shroff and t_.V. Cancio in Polym. Eng.
Sci., Vol. 17, no. 11, p. 770 (1977), and in 'Rheometers for Molten Plastics' by John Dealy, published by Van Nostrand Reinhold Co. (1982) on page 97-9~.
The processing index is measured at a temperature of 190C, at nitrogen pressure of 2500 psig using a 0.0296 inch (752 micrometers) diameter (preferably 0.0143 inch diameter die for high flow polymers, e.g. 50 -100 melt index or greater), 20:1 UD die having an entrance angle of 180 degrees. The GER processing index is calculated in millipoise units from the following equation:

~ 95/07942 P~T'IUS94/1062~
PI = 2.15 % 106 dyne/cm2J(1000 shear rate), An apparent shear stress vs. apparent shear rate plot is used to identify the melt fracture phenomena over a range of nitrogen pressures from 5250 to 500 prig using the die or GER test apparatus pr~eviousfy described. According to amamurthy in Journal of Rheotogy, 30(2), 33'7-357, 10869 above a certain critical flow rate, the observed extrudate irregularities may be broadly classified into two main types: surface melt fracture and gross melt fracture.
surface melt fracture occurs under apparently steady flow conditions arid ranges in detail from loss of specular gloss to the more severe form of ~sl~arkskin". In this disclosure, the onset of surface melt fracture is characterized at the beginning of losing extrudate gloss at which the surface roughness of extrudate can only be detected by 40X magnification. The critical shear rate at onset of surface melt fracture for the substantially linear ethylene polymers is at least 50 percent greater than the critical shear rate at th~~ onset of surface melt fracture of a linear ethylene polymer having about the same 12 and t~~,JMn. Preferably, the critical shear stress at onset of surface melt fracture for the substantially linear ethylene polymers of the invention is greater than about 2.8 x 106 dyne/cm2.
Gross melt fracture occurs at unsteady flow conditions and ranges in detail from regular (alternating rough and smooth, helical, etc.) to random distortions. For commercial acceptability, (e.g., in blown film products), surface defects: should be minimal, if not absent. The critical shear rate at onset of surface melt fracture (OSMF) and critical shear stress at onset of gross melt fracture (OGMF) are based on the changes of surface roughness and configurations of the extrudates extruded by a GER. For the substantially linear ethylene polymers of the invention, the critical shear stress at onset of gross melt fracture is preferably greater than about 4 x 106 dyne/cm2.
For the processing index and melt fracture tests, the ethylene polymers and substantially linear ethylene copolymers contain antioxidants such as phenols, hindered phenols, phosphates or phosphonites, preferably a combination of a phenol or hindered phenol and a phosphate or a phosphonite.
Suitable catalysts for use herein comprise constrained geometry complexes in combination with an activating cocatalyst or activating technique.
Examples of such constrained geometry complexes, methods for their preparation and for their activation are disclosed in EP-A-416,815; EP-A-468,651; EP-A-514,828;
EP-A-520,732; and U.S. Patent 5,374,696; as well as U.S. Patents: 5,055,438, 5,057,475, 5,096,867, 5,064,802 and 5,132,380.

~ 95107942 P°C'TIiJS94/10621 Suitable provided metal complexes far use herein correspond to the form ula:
~Z ~
L Y
cx,)~ c~~, or dimers thereof, wherein:
is a Group 4 metal in the +3 or -+-4 formal oxidation state, preferably is titanium or zirconium, most preferably titaniurr~;
L is a group containing a cyclic, delocalized, aromatic, anionic, II
n is 1 or 2 depending on the formal oxidai:ion state of M.
In one embodiment of this invention, the complexes can be prepared by contacting a precursor Group 4 metal compound containing 2 displaceable lic~and groups with a source of a dianionic iigancl, (L-Z-Yj~°, and optionally, if ~'~ 951~794, I~~i ~/gJ~9~J~~6~1 ', ' ;' A) ~ ) one or morn of the above metal complexes or the reaction product of the above described process, and 2) one or more activating cocatalysts;
or ~) the reaction product formed by converting one or more of the above metal complexes or the reaction product of the above described process to an active catalyst by use of an activating technique.
Preferred examples of X groups include: hydrocarbyl, carboxylate, sulfonate, hydrocarbyloxy, siloxy, arnido, phosphido, sulfido, and silyl groups9 as well as halo-, amino-, hydrocarbyloxy-, siloxy-, silyl-, and phosphino-substituted derivatives of such hydrocarbyl, carboxylate, sulfonate, hydrocarbyloxy, siloxy, amido, phosphido, sulfido, or silyl groups; hydride, halide and cyanide, said group having up to 20 nonhydrogen atoms; or alternatively, two ?C groups together are a hydrocarbadiyi, or a substituted hydrocarbadiyl group wherein the substituent is independently each W~ 95/07942 PC'T/t(1S9~BI10621 occurrence a hydrocarbyl or silyl group of up to 20 nonhydrogen atoms, said group forming a metallacycle, preferably a metallacyclopentene, with .
tore preferred X groups are hydride, hydrocarbyl (including cyclohydrocarbyl), hydrocarbyloxy, amido, silyl, silyihydrocarbyl, siloxy, halide and aminobenzyl. Especially suited are hydride, chloride, methyl, neopentyl, b~'nzyl, phenyl, dimethylamido, 2-(PV,fV-dimethylamino)benzyl, allyl, methyl-substituted allyl (all isomers), pentadienyl, ~-me~thylpentadienyl, 3-methylpentadienyl, 2,4-dimethylpentadienyl, ~,6-dimethylcyclohexadienyl, and trimethylsilylmethyi. l~lore preferred of two X groups together are ~-butene-1,4-diyl, 2,3-dimethyl-1,4-diyl, 2-methyl-~-butene-1,4-diyl, butane-1,4-diyl, propane-1,3-diyl, pentane-1,5-diyl, and 2-penter~e-~,5-diyl.
Preferred ' groups include phosphines, phosphates, ethers, amines, carbon monoxide, salts of Group 1 or 2 metals, and mixtures of the foregoing X' groups. Examples of the foregoing especially include trimethylphosphine, triethylphosphine, trifluoraphosphine, triphenylphosphine, bas-1,2-(dimethylphosphino)ethane, trimethytphosphite, ~triethylphosphite, dirnethylphenylphosphite, tetrahydrofuran, diethyl ether, carbon monoxide, pyridine, bipyridine, tetramethylethylenediamine (TE~A), dimethoxyethane (~tree), dioxane, triethylamine, lithium chloride, and magnesium chloride.
Further preferred metal coordination complexes used according to the present invention correspond to the formula:
Z Y
C IVI ~ CX~
wherein Z, M, Y, X and n are previously defined; and Cp is a C5H4 group bound to Z and bound in an rt5 bonding mode to or is such an ~5 bound group substituted with from one to four substituents independently selected from hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said substituent having up to ~0 nonhydrogen atoms, and optionally, two such substituents (except cyano or halo) together cause Cp to E~ave a fused ring structure.

~'~ 95/0792 ~~"I("I~1~9~1~~6~~
v~ .~
__, . :. C ~: _ I~oro preferred metal coordination complexes used according to the present invention correspond to the formula:
wherein:
R' each occurrence is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said ~' having up to 20 nonhydrogen atoms, and optionally, two ~' groups (where ~' is not hydrogen, halo or cyano~ together form a divalent derivative thereof connected to adjacent positions of the cyclopentadienyl ring to form a fused ring structure;
group from Y form a ring system.
I~I is titanium or zirconium in the +3 or a-4 formal oxidation state; and 3~ is chloro, hydrocarbyl, hydrocarbyloxy, silyl or N, I~-dialkylamino substituted hydrocarbyl group;
n is ~ or 20 Preferably, ~3' independently each occurrence is hydrogen, hydrocarbyl, silyl, halo and combinations thereof said R' having up to ~ 0 nonhydrogen atoms, or two ~t° groups (when R' is not hydrogen or halo) together form a divalent derivative thereof; rr~ost preferably, R' is hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, (including where appropriate all isorners~, cyclopentyl, cyclohexyl, norbornyl, benzyl, or phenyl or two ~' groups (except WO 95I~7942 g'C~'II1S94/10621 hydrogen or halo) are linked together, the entire CSR°4 group thereby being, for examply, an indenyl, tetrahydroindenyl, fluorenyl, tetrahydrofluorenyl, or octahydrofluorenyl group.
wherein:
° is independently each occurence selected from hydrogen, silyl, E is independently each occurrence silic~~n or carbon.
°" is independently each occurrence hydrogen or C~_1p hydrocarbyl;
" is hydrocarbyl or silyl, especially an aryl, benzyl, hydrocarbyl substituted aryl, hydrocarbyl substituted benzyl, secondary or tertiary alkyl or tertiary silyl group of up to 12 nonhydrogen atorr~s;
~1 is titanium in the +3 or +4 formal oxidation state;
mislto2;
n is 1 or 2;
X is methyl, allyl, phenyl, benzyl, chloro, c'.-(N,N-dimethyiamino)benzyl or trimethylsilylmethyl.
Examples of the metal complexes used according to the present in~~ention include compounds wherein R" is methyl, ethyl, propyl, butyl, panty!, _ t xc: v. vcrv : ~rA- ~~it,EVCHEV 0~ " ._ . _2~'-1 I -95 : ~~_> ; 3q, ; 414 2'?3 5055-~ +q.g gg ~g9gq~465 : # 8 ___.. .,.." _____..__..__...
40,121 Q-F ~ . '~ . -_ 1-(t-butyiami do )-2-(tetramethyi-~ ~-cyclopentadienyl)ethanediyititanium {Ifi) 2-(N,PI-dimethylaminolbanzyi 1-it-b~Ylamido)-2-~rl~-indenyl)ethanediyltitanium dimethyi, '1-(t-butylamido)-2-(rt5 indenyl)ethanediyltitanium dibenzyl, (t-butyiamido)(~b~e;rahydroindenyl)dimethylsilanetitanium dimethyi, (t-bu~tylamid~)(~$-tetr,attydroindenyt)dimethylsiianetitanium Biphenyl, 1-(t-butylamido)-2-(rts.tetcahydroindenyl)ethanediyititanium dimethyi, '1-(t-butylamido)-2-(rl~-tetrahydroindenyl)ethanediyhtitaniurn dibenzyl, (t-butylamido)(~~-fluorenyl)dimethylsilanetitanium dimethyf, (t-butyiamido){rl~ ~tuorenyl)dimethylsilanetftanium dibertzyl, 1-(t-butylamido)-2-(~~-tluorenyi)ethanediyititartium dimethyl, 't-(t-butyiamido)-2-~~~-ftuorenyl)ethanediyltitanium dibenzyl,.
{t-butylamidol(~$ tetrahydroftuorenyl)dimethylsilane#itanium dimethyl, (t-butylamido)(rye-tetrahydroiluorenyi)dimethylsiianetitanium dibenzyl, 1-~t-butylamido)-2-(,~~-tetrahydrofluorenyt)ethanediyltitanium dimethyl, 1-(t-butylamido)-2-(rl~-tetrahydro~luorenyi)ethanediyftitanium dibenzyl (t-butyiamido)(~b-ottahydrofluoreny!)dimethylsitanetitanium dimethyl (t-butyiamido){rl5~ctahydrofluorenyi)dimethyisilanetitanium dibenzyl, 1-(t-butylarnido)-2-(~~-octahydrofluorenyl)ethanediyttitanium dirnethyl, '1-{t-butylamido)-2-(rte-o~hydrofluorenyi)ethanediyititanium dibenzyi, and the corresponding airconium or hafnium coordination complexes.
The skilled arti$an will recognize that additional members of the foregoing fist will include the corresponding zirconium or hafnium containing derivatives, as welt as complexes that are variously substituted as horein defined.
Most highly preferred met~i complexes used according to the pfesent inven~on are {9-tent-burfiamido}-2-(tetrsmethyi-~5-cycfopentadienyl)ethanediyftitanium dfmethyl, 1-(tart-butylamidol-2-~tetra-methyt-rt5- cyclopentadionyl)ethanediyititanium dibenayi, 1-(tart- butylamido)-2-,;tetramethyi-,t5- cyciopentadienyl)dimethylsilanetitanium dimethyl, 1-itert-butylamido)-2-{tetrameti,yt-rid- cyciopentadienyi)dimethyisiiane:~~,ani~;m dibenzyi, (t-butylamidfl)(tetramethyf-~rt~-cycivpentadieny!)dimeihyisil2r~titani~:n, ANtEfVDED SHEF'i"

1-(t-butylamido)-2-(tetramethyl-~5-cyclopentad ienyl)ethanediyltitanium, (t-butylamido)(rt5-tetrahydroindenyl)dimethylsilanetitanium dimethyl, (t-butylamido)(~5-tetrahydroindenyl)dimethylsilanetitanium Biphenyl, 1-(t-butylamido)-2-(~b-tetrahydroindenyl)ethanediyltitanium dimethyl, (t-butylamido)(~5-tetrahydrofluorenyl)dimethylsilanetitanium dimethyl, (t-butylamido)(rt5-tetrahydrofluorenyl)dimethylsilanet'rtanium dibenzyl, 1-(t-butylamido)-2-(~b-tetrahydrofluorenyl)ethan.ediyltitanium dimethyl, 1-(t-butylamido)-2-(~b-tetrahydrofluorenyl)ethanediyltitanium benzyl (t-butylamido)(rl5-octahydrofluorenyl)dimethylsilanetitanium dimethyl (t-butylamido)(rl5-octahydrofluorenyl)dimethylsilanetitanium dibenzyl, 1-(t-butylamido)-2-(~5-octahydrofluorenyl)ethanediylt'rtanium dimethyl, 1-(t-butylamido)-2-(~5-octahydrofluorenyl)ethanediyltitanium dibenzyl, The metal complexes used in this invention are rendered catalytically active by combination with an activating cocatalyst or by use of an activating technique. Suitable activating cocatalysts for use herein include neutral Lewis acids other than an alumoxane, such as C1-30 hydrocarbyl substituted Group 13 compounds, especially tri(hydrocarbyl)aluminum- or tri(hydrocarbyl)boron compounds and halogenated (including perhalogenated) derivatives thereof, having from 1 to 10 carbons in each hydrocarbyl or halogenated hydrocarbyl group, more especially perfluorinated tri(aryl)boron compounds, and most especially tris(pentafluorophenyl)borarie; nonpolymeric, compatible, noncoordinating, ion forming compounds (including the use of such compounds under oxidizing conditions), especially the use of ammonium-, phosphonium-, oxonium-, carbonium-, silylium- or sulfonium- salts of compatible, noncoordinating anions, or ferrocenium salts of compatible, noncoordinating anions; bulk electrolysis (explained in more detail hereinafter);
and combinations of the foregoing activating cocatalysts and techniques. The foregoing activating cocatalysts and activating techniques have been previously taught with respect to different metal complexes in the following references: EP-A-277,003, US-5,153,157, US-5,064,802, EP-A-468,651 and EP-A-520,732.

W~ 95107942 PC'~'/uJ~94/10621 Preferred anions are those containing a single coordination complex comprising a charge-bearing metal or metalloid core which anion is capable of balancing the charge of the active catalyst species (the metal canon) which may be formed when the two components are combined. Also, said anion stoould be sufficiently labile to be displaced by olefinic, diolefinic and ac;etylenically unsaturated compounds or other r~eutra! Lewis bases such as ethers or nitrites. Suitable metals include, but are not limited to, aluminum, gold and platinum. Suitable metalloids include, but are not limited to, boron, phosphorus, and silicon. Compounds containing anions which comprise coordination complexes containing a single metal or metalloid atom are, of course, well known and many, particularly such compounds containing a single boron atom in the anion portion, are available commercially.
_2g_ Preferably such cocatalysts may be represented by the following general formula:
[~t-H]+d(Ad-1 wherein:
L' is a neutral Lewis base;
[L*-H]+ is a Bronsted acid;
Ad- is a noncoordinating, compatible anion having a charge of d-, and d is an integer from 1 to 3.
More preferably Ad- corresponds to the formula: [M'k+Qn']d' wherein:
k is an integer from 1 to 3;
n' is an integer from 2 to 6;
n'-k = d;
M' is an element selected from Group 13 of the Periodic Table of the Elements; and Q independently each occurrence is selected from hydride, dialkylamido, halide, hydrocarbyl, hydrocarbyloxy, halosubstituted-hydrocarbyl, halosubstituted hydrocarbyloxy, and halo substituted silylhydrocarbyl radicals (including perhalogenated hydrocarbyl- pefialogenated hydrocarbyloxy- and perhalogenated silylhydrocarbyl radicals), said Q having up to 20 carbons with the proviso that in not more than one occurrence is Q halide. Examples of suitable hydrocarbyloxide Q groups are disclosed in U. S. Patent 5,296,433.
In a more preferred embodiment, d is one, i. e., the counter ion has a single negative charge and is A-. Activating cocatalysts comprising boron which are particularly useful in the preparation of catalysts of this invention may be represented by the following general formula: (L'-H]+ [BQ41-wherein:
[L'-H]+ is as previously defined;
B is boron in a valence state of 3; and Q is a hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-, fluorinated hydrocarbyloxy-, or fluorinated silylhydrocarbyl- group of up to nonhydrogen atoms, with the proviso that in not more than one occasion is Q

W~ 9510?942 PC~'IIJS94I1~621 hydrocarbyl. Most preferably, Q is each occurrence a fluorinated aryl group, especially, a pentafluorophenyl group.
Illustrative, but nat limiting, examples of boron compounds which may be used as an activating cocatalyst in the preparation of the improved catalysts of this invention are tri-substituted ammonium salts such as:
trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, tri(t-butyl)ammonium tetraphenyiborate, N,N-dimethylanilinium tetraphenylborate, N,N-diethylanilinium tetraphenylborate, N,N°dimethyl-2,4,6-trimethylanilinium tetraphenylborate, trimethylammonium tetrakis(pentafiuorophenyl) borate, triethylammonium tetrakis{pentafluorophenyl) borate, tripropylammonium tetrakis(pentafluorophenyl) borate, tri{n-butyl)ammonium tetrakis(pentafluorophenyl) borate, tri(sec-butyl)ammonium tetrakis(pentafluorophenyl) borate, N,N°dimethylanilinium tetrakis(pentafiuorophen'/I) borate, N,N-dimethylanilinium n-butyltris(pentafluorophenyl) borate, N,N-dimethyianilinium benzyltris(pentafluorophenyl) borate, N,N-dimethylanilinium tetrakis(4-(trimethylsilyl)-?, 3, 5, 6-tetrafluorophenyl) borate, N,N-dimethylanilinium tetrakis(4-(triisopropylsilyl)-2, 3, 5, 6-te~trafluorophenyl) borate, N,N-dimethyianilinium pentafluorophenoxytris(pentafluorophenyl) borate, N,N-diethylanilinium tetrakis(pentafluorophenyl) borate, N,N-dimethyl-2,4,6-trimethyianilinium tetrakis(pentafluorophenyl) borate, trimethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, triethylammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate, tripropylammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate, tri(n-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate, dimethyl(t-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate, N,N-dimethyianilinium tetrakis(2,3,4,6-tetrafluorophenyl) borate, N,N-diethylanilinium tetrakis(2,3,4,6-tetrafluorophenyl) borate, and N,N-dimethyl-2,4,6-trimethylanilinium tetrakis(2,3,4,6-tetrafluorophenyl) borate;
dialkyl ammonium salts such as:

~'~ 95/07942 I~CC1C/E~J~9~I~0~~~
.. > .. -~, . ~~ ~_ Preferred [L''-H]~ cations are ~I,N-dirr~ethylar~ilinium and tributylamm~niur~.
~rtother suitable iota forming, activating cocatalyst comprises a salt of a cationic oxidizing agent and a noncoordinating, compatible anion represented by the formulae (~~e~)d(~d-)e wherein:
~xe~' is a cationic oxidizing agent having a charge of e°~9 a is an integer from ~ to 3; and Ad- and d are as previously defined.
~xar~ples of cationic oxidizing agents include: ferrocenium, hydrocarbyl-substituted ferroceniurn, Age, or Pb'~~. Preferred ernbodirnents of Ad- are those anions previously defined with respect to the ~ronsted acid containing activating cocatalysts, especially tetrakis(pentafluorophenyl)borate.
-2~-Another suitable ion forming, activating cocatalyst comprises a compound which is a salt of a carbeniurri ion and a noncoordinating, compatible anion represented by the formula:
Oi-A' wherein:
C~ is a C1_20 carbenium ion; and A- is as previously defined. A preferred carbenium ion is the trityl ration, i.e., triphenylmethylium.
A further suitable ion forming, activating cocatalyst comprises a compound which is a salt of a silylium ion and a noncoordinating, compatible anion represented by the formula:
R3Si(X')q+A-wherein:
R is C1_10 hydrocarbyl, and X', q and A- are as previously defined.
Preferred silylium salt activating cocatalysts are trimethylsilylium tetrakis(pentafluorophenyl)borate, triethylsilylium(tetrakispentafluoro)phenylborate and ether subst'ttuted adducts thereof. Silylium salts have been previously generically disclosed in J. Ghem Soc. Chem.Comm., 1993, 383-384, as well as Lambert, J. B., et al., Organometallics, 1994, 13, 2430-2443. The use of the above silylium salts as activating cocatalysts for addition polymerization catalysts is known.
Certain complexes of alcohols, mercaptans, silanols, and oximes with tris(pentafluorophenyl)borane are also effective catalyst activators and may be used according to the present invention. Such cocatalysts are disclosed in USP 5,296,433. Preferred complexes include phenol, especially fluorinated phenol adducts of tris(pentafluorophenyl)borane. The latter cocatalysts are disclosed and claimed in United States Patent 5,296,433.
The technique of bulk electrolysis involves the electrochemical oxidation of the metal complex under electrolysis conditions in the presence of a supporting electrolyte comprising a noncoordinating, inert anion. In the technique, solvents, supporting electrolytes and electrolytic potentials for the electrolysis are used such that electrolysis byproducts that would render the metal complex catalytically inactive are not substantially formed during the reaction. More particularly, suitable solvents are materials that are: liquids under the conditions of the electrolysis (generally temperatures from 0 to 100C), capable of dissolving the supporting electrolyte, and inert. "Inert solvents" are those that are not reduced or oxidized under the reaction conditions employed for the electrolysis. It is generally possible in view of the desired electrolysis reaction to choose a solvent and a supporting electrolyte that are unaffected by the electrical potential used for the desired electrolysis.
Preferred solvents include difluorobenzene (all isomers), dimethoxyethane (DME), and mixtures thereof.
The electrolysis may be conducted in a standard electrolytic cell containing an anode and cathode (also referred to as the working electrode and counter electrode respectively). Suitable materials of construction for the cell are glass, plastic, ceramic and glass coated metal. The electrodes are prepared from inert conductive materials, by which are meant conductive materials that are unaffected by the reaction mixture or reaction conditions.
Platinum or palladium are preferred inert conductive materials. Normally an ion permeable membrane such as a fine glass frit separates the cell into separate compartments, the working electrode compartment and counter electrode compartment. The working electrode is immersed in a reaction medium comprising the metal complex to be activated, solvent, supporting electrolyte, and any other materials desired for moderating the electrolysis or stabilizing the resulting complex. The counter electrode is immersed in a mixture of the solvent and supporting electrolyte. The desired voltage may be determined by theoretical calculations or experimentally by sweeping the cell using a reference electrode such as a silver electrode immersed in the cell electrolyte. The background cell current, the current draw in the absence of the desired electrolysis, is also determined. The electrolysis is completed when the current drops from the desired level to the background level. In this manner, complete conversion of the initial metal complex can be easily detected.
Suitable supporting electrolytes are salts comprising a ration and a compatible, noncoordinating anion, A-. Preferred supporting electrolytes are salts corresponding to the formula G+A-; wherein:
G+ is a ration which is nonreactive towards the starting and resulting complex, and A- is as previously defined.
Examples of rations, G+, include tetrahydrocarbyl substituted ammonium or phosphonium rations having up to 40 nonhydrogen atoms.
Preferred rations are the tetra-n-butylammonium- and tetraethylammonium-rations.
During activation of the complexes of the present invention by bulk electrolysis the ration of the supporting electrolyte passes to the counter electrode and A- migrates to the working electrode to become the anion of the resulting oxidized product. Either the solvent or the ration of the supporting electrolyte is reduced at the counter electrode in equal molar quantity with the amount of oxidized metal complex formed at the working electrode. Preferred supporting electrolytes are tetra.hydrocarbylammonium salts of tetrakis(perfluoroaryl) borates having from 1 to 10 carbons in each hydrocarbyl or perfluoroaryl group, especially tetra-n-butylammonium tetrakis(pentafluorophenyl) borate.
A further recently discovered electrochemical technique for generation of activating cocatalysts is the electrolysis of a disilane compound in the presence of a source of a noncoordinating compatible anion. This technique is more fully disclosed and claimed in United States Patent 5,625,087.

~V~ 951079~~ I~~'~'IgT~~~lb~6~.ll - ',, the foregoing activating techniques and ion forming cocatalysts are also preferably used in cor~binatior~ ~itc~ a tri(hydrocarbyl)al~rnin~r~ or tri(hydrocarbyl)borane compound having from ~ to ~ carbons in each hydrocarbyl groups acid, especially tris(pentafluorophenyl)borane.
Upon activation of the metal complexes containing taro distinct ~C
groups, utilizing one of the preceding cation forming activating cocatalysts or activating techniques, there is believed to be formed, ~titho~t wishing to be bound by such belief, a cationic metal complex corresponding to the formula:
Z Y
L
t~~-1 whereine I~i9 ~9 Z, ~, X', , n, and q are as previously defined, and ~° is as previously defined and is the noncoordinating anion from the activating cocatalyst or is formed concurrently by the activating technique.

~ 95/07942 ~~'T'Ii159411062~
lJtilizing the preferred neutral Lewis acid activating cocatalyst, ~(C~~~)3 , A° of the foregoing cationic metal complexes is believed to correspond to the formula: ~(C6F~)~°,wherein X is as previously defined.
The preceding formula can be considered as a limiting, charge separated structure. However, it is to be understood that, particularly in solid form, the catalyst may not be fully charge separated. That is, the group may retain a partial covalent bond to the metal atorr~, t~.
Z Y
tVf ~ X
Z
L ~. Ci?3 Cf~R6 CRt R2 ~~ 9~l~7~4~ I~e~'~'/~J~~~l~~~~~
~, 'e whereine ~ as t~t~r9i~r~ or arc~ni~r~p ~y ~y and ~ are as proveousiy def'ned, i:3~ y ~~y ~~, ~~., R~, and ~6 are independently each occurrence hydrogen or a hydrocarbyl or silyl group having from ~ to 2~ r~onhydroger~
atoms;
~ is boron ire a valence state of 3, and ~ is as previously defined.
~ther catalysts which are useful as the catalyst compositions of this inve~tior~y especially compounds containing other Croup ~ metals9 wills of courser be apparent to those skilled in the art.
~escriotion of a Continuous Polymerization 'fhe ~oiymerization reaction to initiate the polymerization reaction.

Typically the various comonomers that are copolymerized with ethylene in order to provide polymers having the desired density range at any given melt index range from 0 to 20 mol percent in the copolymer. The relative molar concentration of such comonomers to ethylene (CX/C2), which are present under reaction equilibrium conditions in the reactor will vary depending on the choice of comonomer and the desired copolymer density.
A fluidized bed reaction system which can be used in the practice of the process of the present invention is taught in U.S. Patent 4,543,399. A typical fluidized bed reactor can be described as follows:
The bed is usually made up of the same granular resin that is to be produced in the reactor. Thus, during the course of the polymerization, the bed comprises formed polymer particles, growing polymer particles, and catalyst particles fluidized by polymerization and modifying gaseous components pass upward through the bed at a flow rate or velocity sufficient to cause the particles to remain separated with the bed exhi5iting fluid-like behavior. The fluidizing gas comprises the initial gaseous feed of monomers, make-up feed, and cycle (recycle) gas, i.e., comonomers, hydrogen and, if desired, an inert carrier gas. Examples of such inert carrier gases include nitrogen, methane, ethane or propane, which are inert with respect to the polymerization reaction.
The essential parts of the reaction system are the polymerization reaction vessel, catalyst injection system, the fluidized bed, the gas distribution plate, inlet and outlet piping, a compressor, cycle gas cooler, and a product discharge system. In the vessel, there is a reaction zone which contains the bed and a velocity reduction zone which is above the reaction zone. Both are above the gas distribution plate. Advantages of the product of subject process are the homogeneity and uniformity of the physical properties throughout the resulting polymer and the high strength and toughness obtained without processing difficulty.

It will be apparent to the skilled artisan that use of a supported constrained geometry catalyst increases the range of reactor conditions.that may be used before condensing components in the recycle stream. But if one chooses to condense components in the recycle stream, then it may be desirable in some instances to raise the dew point temperature of the recycle stream to further increase heat removal as taught in U.S. Patents 4,543,339 and 4,588,790 . The recycle stream dew point temperature can be increased by: (1 ) raising the operating pressure of the reaction system; (2) increasing the concentrations of inert condensable compounds in the reaction system; and/or (3) reducing the concentration of inert non-condensable compounds in the reaction system. In one embodiment of this invention, the dew point temperature of the recycle stream may be increased by the addition of a condensable fluid to the recycle stream which is inert to the catalyst, reactants, and the products of the polymerization reaction.
me fluid can be introduced into the recycle stream with the make-up fluid or by any other means or at any other point in the system. Examples of such fluids are saturated hydrocarbons, such as butanes, pentanes or hexanes.
A primary limitation on the extent to which the recycle gas stream can be cooled below the dew point is in the requirement the gas to-liquid ratio be maintained at a level sufficient to keep the liquid phase of the two-phase recycle mixture in an entrained or suspended condition until the liquid is vaporized. It is also necessary for sufficient velocity of the upwardly flowing fluid stream in the reaction zone to maintain fluidization of the bed. This limitation can be overcome by collecting the condensed phase and introducing it to the fluidized bed separately from the recycled gaseous stream.
Multiple reactor polymerization processes are also useful in the present invention, such as those disclosed in U.S. Patents 3,914,342, 5,047,468, 5,126,398 and 5,149,738..
The multiple reactors can be operated in series or in parallel, with at least one constrained geometry catalyst employed in at least one of the reactors.
In this aspect of this invention resins are manufactured and blended in situ.
Multiple reactor polymerization processes may be used to produce in-situ blended polymers with enhanced physical properties and/or processability. In-situ blends of dififierent molecular weights and/or different densities may be produced for specific and desired physical and/or processability requirements.
For example, two reactors can be used in series to produce resins with a bimodal molecular weight distribution. In another example, two reactors could produce resins with a bimodality in density or short chain branching. More than two reactors in series can be used to make more molecular weight or density components for in-situ blends. Each reactor separately can have a constrained geometry catalyst or a conventional Ziegler-Natta catalyst as needed for obtaining the in-situ blended polymer with the desired properties, as long as there is a constrained geometry catalyst in at least one reactor.
The constrained geometry catalysts may be used singularly, in combination with other constrained geometry catalysts, or in conjunction with Zeigler-type catalysts in separate reactors connected in parallel or in series.
The Zeigler catalyst is generally a titanium based complex suitably prepared for use as a catalyst for the gas phase polymerization of olefins. This complex and methods for its preparation are disclosed in U.S. Patents 4,302,565, 4,302,566, 4,303,771, 4,395,359, 4,405,495, 4,481,301, and 4,562,169.
The polymerization in each reactor is conducted in the gas phase using a continuous fluidized bed process. A typical fluidized bed reactor is described in U.S. Pat. No. 4,482,687 issued on Nov. 13, 1984.
As noted, the reactors may be connected in series as taught in U.S. Patents 5,047,468, 5,126,398, and 5,149,738 .
While two reactors are preferred, three or more reactors can be used to further vary the molecular weight distribution.
As more reactors are added producing copolymers with different average molecular weight distributions, however, the sharp diversity of which two reactors are capable becomes less and less apparent. It is contemplated that these additional reactors could be used to produce copolymers with melt indices or densities, intermediate to the high and low melt indices previously referred to.
As noted previously, two or more reactors may be run in parallel with the resulting polymeric product being blended. This permits the reactors to be run independently, with different catalysts, different amounts of ethylene and alpha-olefins, different recycle rates and at different productivity rates.
The various melt indices can be prepared in any order, i.e., in any reactor in the series. For example, the low melt index copolymer can be made in the first or second reactor in the series and the high melt index copolymer can be made in the first or second reactor as well. The actual conditions used will depend on the comonomer used and the desired copolymer properties and are readily ascertained by the skilled artisan.
The constrained geometry catalyst, the ethylene monomer; any comonomers and hydrogen, ff any, are continuously fed into each reactor and ethylene copolymer and active catalyst are continuously removed from one reactor and introduced into the next reactor. The product is continuously removed from the last reactor in the series.
The alpha-olefins used in this aspect of the invention are the same as those that have been previously described in this application. Preferred alpha-olefins are 1-butane, propylene, 1-hexane, 1-octane, 4-methyl-1-pentane and styrene.
~ul2~oorted Hom2qeneous Catalyrsts Supported homogeneous catalyst complexes can be used in the process taught by applicants.
The Catalyst Support Typically, the support can be any of the known solid catalyst supports, particularly porous supports, such as talc, inorganic oxides, and resinous support materials such as polyolefins. Preferably, the support material is an inorganic oxide in particulate form.
Suitable inorganic oxide materials which are desirably employed in accordance with this invention include Group 2, 3, 4, 13, or 14 metal oxides.
The most preferred catalyst support materials include silica, alumina, and silica-alumina, and mixtures thereof. Other inorganic oxides that may be ~'~ 95/07942 P~'T/i1~94/~0621 N.
employed either alone or in combination with the silica, alumina, or silica-alumina are magnesia, titania, zirconia. Other suitable support materials, however, can be employed, for example, finely divided polyolefins such as finely divided polyethylene.
Chemical dehydration or chemical treatment to dehydrate the support may be accomplished by slurrying the inorganic particulate material, such as, ~~or example, silica in an inert low boiling hydrocarbon, such as, for example, silica in an inert low boiling hydrocarbon, such as, for example, hexane.
wring the chemical dehydration reaction, the aupport, preferably silica, should be maintained in a moisture and oxygen-free atmosphere. To the silica slurry _3~_ ~'~ 95/~79~~ ~f~'~I'ItiJ~9b/~~~~~
..r .. a .n .. "sJ
Ire ~rder ~h~~ pers~ns skil9~d in the ark rna~r beater underscored the Ex~~rirnen~ai _3~_ gases then pass through a gas booster pump. The polymer is allowed to accumulate in the reactor over the course of the reaction. The total system pressure is kept constant during the reaction by regulating the flow of the ethylene into the reactor. Polymer is removed from the reactor to a recovery vessel by opening a valve located at the bottom of the fluidization zone. The polymer recovery vessel is kept at a lower pressure than the reactor. The pressures of ethylene, comonomer and hydrogen reported refer to partial pressures. The polyethylene powders used as supports were high density homopolymers. The titanium complex, (C5Me4SiMe2NCMe3)TiM~2 is prepared according to U.S. Patent 5,189,192, and the borane complex, B(C6F5)3 is prepared according to the procedure taught in Z. Naturforsch. ~Q~, 5-11 (1965).
Prior to being used as supports, the silicas were treated with the aluminum alkyl, triethylaluminum (TEA). The purpose of this pretreatment was to remove from the silica any residual water and/or hydroxyl groups. Following the pretreatment, the silicas were then washed several times with toluene to remove any residual TEA or alumoxane which may have resulted during the dehydration process. The supports were then dried under reduced pressure.
In some cases the supports were washed with hexane before drying. Any amount of alumoxane which may have remained on the silica was present in a non-activating amount (see Examples 20 and 21 ).

Catalyst/support preparation An aliquot (4 mL) of a 0.005 M solution (60 Nmol) of (C5Me4SiMe2NCMe3)TiMe2 in toluene and 4.8 mL of a 0.005 M solution (60 Nmol) of B(C6F5)3 in toluene were stirred with 0.640 g of high density polyethylene powder having zero melt index which previously had been sieved to remove any particles larger than 25 mesh. The solvent was removed to give a pale yellowish free-flowing powder. The resulting catalyst composition was divided into two portions, each weighing about 0.32 g.
Polymerization 1~(~~IYI~1~~4~/~l~~e~~
~~ 95107~4~
w~
__J ~( t. 4 Catalyst/support preparation ~olyrr,eriz~tion ~x~rr»I~ 3 Catalystlsupport preparation in a ~ar~r~er substantially the same as in Example ~ , except that 2 r~~
(~0 Nrz~ol) of the (C5~e4Si~e2~~~e3)TiMe~ solution and ~.~ m~. (~~ pmol) of the ~(COE~)~ solution were combined with 0.600 g of t ~ .~ melt index egp_ ~17~103 polyethylene powder to prepare the supported catalyst. 0.30 g of the resulting supported catalyst (5 Nmol titanium complex, 6 Nmol borane complex) was used in the following polymerization.
Polymerization The polymerization was carried out in two stages, similar to Example 2, except that the ethylene pressure was 300 psi. No hydrogen was present during the polymerization. The initial temperature was 61 °C. The second portion of catalyst was added about 1 hour after the first portion of catalyst had been added. The yield of granular polymer having a melt index of zero was 25.4 g.
Examl la a 4 Catalyst/support preparation A polyethylene-supported catalyst was formed analogous to Example 3, except that 0.59 melt index polyethylene and 12 Nmol of the borane complex were used.
Polymerization The polymerization was carried out analogous to Example 3, except that the ethylene pressure was 290 psi. No hydrogen was present during the polymerization. The initial temperature was 66°C. An exotherm of 4°C was observed on addition of the first portion of catalyst. An exotherm of 24°C was observed on addition of the second portion of catalyst. The yield of granular polymer having a melt index of zero was 43.9 g. ' Exam,~he 5 Catalyst/support preparation An aliquiot (4 mL) of a 0.~05 M solution {20 Nmol) of (C5Me4SiMe2NCMe3)TiMe~°rn'~aJ~~~~ and 4.8 mL of a 0.005 M solution (24 _~.1 _ m.v. r__~o,~~~~.:.vtl.c:y Vb r ILy ~.. -_ . =='' _ 11 X95 : '?~or ;34 ...-. _____ 41~ 223 5055.-~ +49 g9 2:3994 4ss:# s 40,121Q-F . . _~ ~___ 2~~7910~
umolj of B(C6F5)3 in toluene were s#irred with O.CGO g of Q.33 melt index high density polyethylene pQ,,~er which previously had been sieved to remove an Y
particl$s larger than 25 mesh. The solvent was removed to give a pale yellowish free-tlnwing Powder.
Polymerization An amount (0.30 g; 10 Nmol titanium Complex, 12 Nmol borane complex) of the solid supported catalyst was Introduced into a fluidizsd bed reactor preSSUrized to 260 psi ethyie,~ ~rytaining 0.25 rnol '~G (based on ethylene 0.6,5 psij hydrogen at a temperature of 53°C. After a run time of 5 hours 81 g of polyethylene hawing a melt index of 1.30 was removed. The productivity was 169;000 g polymerlg Ti.
Exam~nle 6_ Catalystfsupport preparation 1n a manner substantially the same as in F~carriple 1, except that 2 mL
(10 ~rmol) of the (C6Me~SilVle2NCMe3)TilIAe2 solution and 2.4 mL (12 Nmot) of the B(C6F5j3 solution were combined with 0.60Q g of 0.33 melt index polyothyiene powder to prepare the supported catalyst. 0.30 g of the resulting $uPPa~ed catalyst (5 Nmol titanium complex, 6 pmol borane complex) ryas used in the following pvtyrr~eriZ~on.
Polymerlaation The polymerization yeas carried out as In Example 5, except that the ethylene and hydrogen pre$sures were 230 psi and O. d6 psi (Q_20 mol %), respectively, at a temperature of 47~C. The yield of polymer having a melt index of 0.65 was 27, 0 g.
-~.2-AMENDED SHEET

~ 95/07942 Exam Bye 7 Polymerization PCT'/CTS94/10621 The polymerization was carried out as in Example 6, except that the ethylene and hydrogen pressures were 230 psi and 1.4 psi (0.50 mol °/~)y respectively, at a temperature of 55°C. The yield of polymer having a melt index of 17.3 was 11.6 g.
Exam Ip a 3 ~atalyst/support preparation Polymerization lJsing the catalystlsupport prepared above, the polymerization was carried out in a manner similar to Example 5, excoept that the ethylene and hydrogen pressures were X70 psi and 0.3 psi (0.30 mol ~/~), respectively, at a temperature of 60°C. The yield of polymer having a melt index of 3.0 was 30.4 g.
_43_ ~'~ ~5l~7~~~ ~'~B'l~1~~9/~t~~2ll ,;
J
~X~r$"i~~~S ~~1 ~
Supp~rt preparation °~h~ silicas ~er~ pretreated pri~r t~ catalyst ~dditior~ pith ~ac~urra.
Preparati~n ~~ the supported catalyst General pelyrraeri~ation procedure ~~4_ ~R'~ 95107942 PC1'/ITS94I10621 n.
iExam 9~c a 20 ~;atalyst/support preparation ~avison 952 silica was pretreated as in Examples 9-19 under '°Support preparation'° using 0.5 mL of TEA and 2.0 g silica.
The catalyst was prepared as in Examples 9-19 under "Preparation of the Supported catalyst" using 3 g.mole of (CSA~Je4Sie2NCe3)Ti~e2, 9 .mole of ~(C6F5)3 and 0.10 g of the above treated silica.
Polymerization The solid supported catalyst was invrodu~ced into the fluidized bed reactor pressurized with 240 psi ethylene, 9 psi 1-butane, 1.2 psi hydrogen and 51 psi nitrogen. The initial temperature was 74~ and the run time was 7~
minutes. The yield of granular powder was 5.5 g.
Example 21 Catalyst/support preparation l9sing the silica of Example 20, the silica-supported catalyst was prepared analogously to Example 20 except that none of the borane complex was added to the support.
Polymerization The solid supported catalyst was introduced into the fluidized bed reactor pressurized with 240 psi ethylene, 9 psi '1-butane, 1.2 psi hydrogen and 51 psi nitrogen. The initial temperature was 75C and the run time was 75 minutes. No polymer was recovered from the reactor, indicating that any aluminum compounds possibly remaining after washing the silica to remove re:;idual TEA are only present at non-activating levels.
_45_ ~~ 95l~7~~~ I1'~'~'/I1i11~~~1g~~~~
-~, , fi_~, ~ ~ ~ ~,.
~x~r~ 1 ~~t~9yst9support preparation f~rop~r~tior~ of the supported catalyst was analogous to ~~~rnple 20 except that ~2 ~.rnole of ~~~6F5)3 and 4 ~.rnole of (C5e4Si~le2l~Ceg)Ti&~e2, were added to 0.20 g of the treated si6ica.
~olyrr~eri~ati~r~
The solid supported catalyst was introduced into the fluidized bed reactor pressurized with 240 psi ethylene, ~ .5 psi, ~ ,5-hexadsene, ~ .2 psi hydrogen, and 60 psi nitrogen. The initial temperature was 76 ~ and the run $irne eras X26 minutes. 21 g of free flowing polymer powder were rerruo~ed.
Examele 23 ~atalystdsupport preparation The supported catalyst was prepared analogously 9~0 ~xarnple 22.
polymerisation The solid supported catalyst was introduced into the fiuidized bed reactor pressurized with 240 psi ethylene, 0.75 psi 1,5-hexadiene, ~ .2 psi hydrogen, and 60 pie nitrogen. The initial temperature was ~0 C and the run titres was ~ ~7 minutes. 1 ~ .6 g of free flowing polymer powder were removed.
m46-~ 95/07942 P~TiYYTS94110621 E~~am h 24 Catalystlsupport preparation Preparation of the supported catalyst vuas analogous to Example 20 except that 9 mole of E(Cgl°5)3p 3 p.mole of (C~P~Ie~ ;ie2NCi~e~)Tie2, and 0.10 g of the treated silica r~rere used.
Polymerization Exam ire 25 Catalystlsupport preparation The supported catalyst vvas prepared an~~logously to Example 24.
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_48_

Claims (23)

CLAIMS:

1. A fluidized bed gas phase process for the production of an ethylene polymer comprising reacting by contacting under polymerization conditions ethylene or ethylene and at least one of a copolymerizable alpha-olefin or diolefin in the presence of a catalyst characterized by an absence of an activating amount of alumoxane, comprising:
A) 1) a metal complex corresponding to the general formula:
or dimers thereof, wherein:
M is a Group 4 metal in the +3 or +4 formal oxidation state;
L is a group containing a cyclic, delocalized, aromatic, anionic, .pi. system and the inertly substituted derivatives thereof through which the L group is bound to M, and which L group is also bound to Z, said L group containing up to 60 non-hydrogen atoms;
Z is a moiety covalently bound to both L and Y, comprising boron, or a member of Group 14 of the Periodic Table of the Elements, said moiety having up to 60 non-hydrogen atoms;

Y is a moiety comprising nitrogen, phosphorus, sulfur or oxygen through which Y is covalently bound to both Z and M, said moiety having up to 25 non-hydrogen atoms;
X' independently each occurrence is a Lewis base containing up to 40 non-hydrogen atoms;
X independently each occurrence is a monovalent anionic moiety having up to 20 non-hydrogen atoms, provided however that neither X is an aromatic group that is .pi.-bonded to M, optionally, two X groups may be covalently bound together forming a divalent dianionic moiety having both valences bound to M, or further optionally one or more X and one X' group may be bonded together thereby forming a moiety that is both covalently bound to M and coordinated thereto by means of Lewis base functionality;
q is a number from 0 to 1; and n is 1 or 2 depending on the formal oxidation state of M;
2) an activating cocatalyst selected from the group consisting of (i) C1-C30 hydrocarbyl substituted boranes and halogenated derivatives thereof, and (ii) borates of the general formula:
[L*-H]+[BQ4]-wherein:
L* is a neutral Lewis base;
[L*-H]+ is a Bronsted acid;
B is boron in a valence state of 3; and Q is a hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-, fluorinated hydrocarbyloxy-, or fluorinated silylhydrocarbyl-group of up to 20 non-hydrogen atoms, with the proviso that in not more than one occasion is Q
hydrocarbyl; and 3) an inorganic oxide support which is substantially free of adsorbed moisture or surface hydroxyls; or B) the complex of the above formula is electrochemically oxidized to an active catalyst under electrolysis conditions in the presence of a supporting electrolyte comprising a noncoordinating, inert anion.

2. The process according to claim 1, wherein M is titanium and X each occurrence is a monovalent ligand group of up to 20 non-hydrogen atoms.

3. The process according to claim 2, wherein X is methyl or benzyl.

4. The process according to claim 2, wherein X is a C1-20 hydrocarbyl group or 2X taken together are a hydrocarbadiyl group.

5. The process according to any one of claims 1 to 4, wherein the ethylene polymer contains >= 80 mol percent of ethylene and <= 20 mol percent of one or more alpha-olefin or diolefin comonomers.

6. The process according to any one of claims 1 to 5, wherein L is a cyclopentadienyl, indenyl, fluorenyl, tetrahydroindenyl, tetrahydrofluorenyl or octahydrofluorenyl group.

7. The process according to any one of claims 1 to 6, wherein the support is silica, alumina, clay, talc or a mixture thereof.

8. The process according to any one of claims 1 to 7, wherein Y is -O-, -S-, -NR*-, -PR*, and R* is independently a hydrocarbyl or silyl group having up to 12 non-hydrogen atoms.

9. The process according to any one of claims 1 to 8, wherein the resulting ethylene polymer has a density of about 0.85 to 0.96 g/cm3 and a melt index of less than 100 g/10 min measured in accordance with ASTM D-1238 (190°C/2.16 kg).

10. The process according to any one of claims 1 to 9, wherein the gas phase fluid bed reaction is carried out at a pressure less than 1000 psi and at a temperature of from about 0 to 110°C.

11. The process according to any one of claims 1 to 10, wherein the activating cocatalyst is a tris(pentafluorophenyl)borane.

12. The process according to any one of claims 1 to 11, wherein said process is conducted in at least two fluidized bed gas phase reactors connected in series or in parallel.

13. The process according to claim 12, wherein said process is conducted in at least two fluidized bed gas phase reactors connected in series.

14. The process of claim 12 or 13, wherein the catalyst system in one reactor further comprises a supported Ziegler catalyst.

15. The process of any one of claims 1 to 14, in which the support is pretreated.

16. A fluidized bed gas phase process for the production of an ethylene polymer comprising reacting by contacting under polymerization conditions ethylene or ethylene and at least one of a copolymerizable alpha-olefin or diolefin in the presence of a catalyst characterized by an absence of an activating amount of alumoxane, comprising:
A) 1) a metal complex corresponding to the general formula:
wherein:
R' each occurrence is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said R' having up to 20 non-hydrogen atoms, and optionally, two R' groups (where R' is not hydrogen, halo or cyano) together form a divalent derivative thereof connected to adjacent positions of the cyclopentadienyl ring to form a fused ring structure;
Y is -O-, -S-, -NR*-, -PR*-;
Z is SiR*2, CR*2, SiR*2SiR*2, CR*2CR*2, CR*=CR*, CR*2SiR*2, or GeR*2; wherein:
R* each occurrence is independently hydrogen, or a member selected from the group consisting of hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, said R* having up to 20 non-hydrogen atoms, and optionally, two R* groups from Z (when R* is not hydrogen), or an R* group from Z and an R* group from Y form a ring system;
M is titanium or zirconium in the +3 or +4 formal oxidation state;
X is chloro, hydrocarbyl, hydrocarbyloxy, silyl or N,N-dialkylamino substituted hydrocarbyl group; and n is 1 or 2;
2) an activating cocatalyst selected from the group consisting of (i) C1-C30 hydrocarbyl substituted boranes and halogenated derivatives thereof, and (ii) borates of the general formula:
[L*-H]+[BQ4]-wherein:
L* is a neutral Lewis base;
[L*-H]+ is a Bronsted acid;
B is boron in a valence state of 3; and Q is a hydrocarbyl-, hydrocarbyloxy-, fluorinated hydrocarbyl-, fluorinated hydrocarbyloxy-, or fluorinated silylhydrocarbyl-group of up to 20 non-hydrogen atoms, with the proviso that in not more than one occasion is Q
hydrocarbyl; and 3) an inorganic oxide support which is substantially free of adsorbed moisture or surface hydroxyls; or B) the complex of formula (I) is electrochemically oxidized to an active catalyst under electrolysis conditions in the presence of a supporting electrolyte comprising a noncoordinating, inert anion.

17. The process according to claim 16, wherein M is titanium.

18. The process according to claim 16 or 17, wherein X
is a C1-20 hydrocarbyl group.

19. The process according to any one of claims 16 to 18, wherein the ethylene polymer contains >= 80 mol percent of ethylene and <= 20 mol percent of one or more alpha-olefin or diolefin comonomers.

20. The process of any one of claims 16 to 19, in which the support is pretreated with triethylaluminum.

21. The process according to any one of claims 16 to 20, in which the support is silica, alumina, clay, talc or a mixture thereof.

22. The process according to any one of claims 16 to 21, in which the support is pretreated.

23. The process according to claim 22, in which the support is pretreated with triethylaluminum.