Patent Description:
Embodiments of the present disclosure generally relate to procatalysts containing high oxidation state transition metal compounds that may be used to produce ethylene-based polymers. More specifically, embodiments of the present disclosure relate to procatalysts containing high oxidation state transition metal compounds, with the exception of vanadium, that may be used to produce ethylene-based polymers with an increased high density fraction.

Ethylene-based polymers are commonly used in a variety of applications depending on the structure of the polymer. For example, high density polyethylene (HDPE) may be used as bottles, piping, geomembranes, plastic lumber, etc. It has been estimated that approximately <NUM> million metric tons of HDPE is produced each year.

HDPE has a large strength to density ratio. Although the density of HDPE is only marginally higher than that of low-density polyethylene (LDPE), HDPE has little branching, giving it stronger intermolecular forces and tensile strength than LDPE. The difference in strength exceeds the difference in density, giving HDPE a higher specific strength. It is also harder and more opaque and can withstand somewhat higher temperatures (e.g., <NUM>/ <NUM> °F for short periods). The lack of branching may be ensured by an appropriate choice of catalyst and reaction conditions.

Ziegler-Natta catalysts have been used for many years in producing a variety of polyethylenes, including HDPE. These catalysts generally include a magnesium halide support and at least one catalyst compound.

<CIT> relates to dual transition metal catalysts exhibiting high activity for the polymerization of alpha-olefins prepared by reacting a tetravalent hydrocarbyloxy titanium halide with chromium oxide and combining the resulting product, preferably in the presence of an inert solid catalyst support, with an organometallic activating agent such as trialkyl aluminum.

<CIT> relates to alpha-olefins are polymerized in the presence of a catalyst which comprises (A) a zirconium carboxylate, a chromium carboxylate or mixture thereof; (B) a solid catalyst support; (C) an organometallic activating agent or cocatalyst and (D) a trivalent or tetravelent titanium compound.

<CIT> relates to catalyst compositions comprising three or more transition metals effective in increasing catalyst efficiency, reducing polydispersity, and increasing uniformity in molecular weight distribution when used in olefin, and particularly, linear low density polyethylene (LLDPE), polymerizations.

Though effective, Ziegler-Natta catalysts are generally limited in their ability to produce differentiated polymers, such as making ethylene-based polymers having very high polymer density or very low polymer density under normal polymerization conditions. Accordingly, there is an ongoing need for procatalysts, catalysts, and processes for producing new, differentiated HDPE polymers. In particular, there is an ongoing need for procatalysts, catalysts, and processes for producing ethylene-based polymers with increased high density fraction (HDF). The present disclosure is directed to procatalysts, catalysts, and processes utilizing these procatalysts and catalysts to produce ethylene-based polymers having increased HDF.

According to at least one embodiment, a procatalyst, comprises: a preformed magnesium chloride catalyst support having a surface area of greater than or equal to <NUM><NUM>/g; a titanium containing component; a chlorinating agent; and a hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+, wherein the hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+ does not comprise vanadium; wherein the transition metal compound is a metal-ligand complex and.

According to another embodiment, a catalyst comprises:as defined in the claim <NUM> as appended hereto.

According to another embodiment, a method for preparing a procatalyst as defined in the claim <NUM> as appended hereto.

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows and the claims.

The term "polymer" refers to a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term "homopolymer," usually employed to refer to polymers prepared from only one type of monomer as well as "copolymer," which refers to polymers prepared from two or more different monomers.

"Ethylene-based polymer" shall mean polymers comprising greater than <NUM>% by weight of units that have been derived from ethylene monomer. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of ethylene-based polymer known in the art include Low Density Polyethylene (LDPE); Linear Low Density Polyethylene (LLDPE); Ultra Low Density Polyethylene (ULDPE); Very Low Density Polyethylene (VLDPE); single-site catalyzed Linear Low Density Polyethylene, including both linear and substantially linear low density resins (m- LLDPE); Medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE).

As used herein, a "solution polymerization reactor" is a vessel that performs solution polymerization, wherein ethylene monomer, optionally with a comonomer, polymerizes or copolymerizes after being dissolved in a non-reactive solvent that contains a catalyst. Heat may be removed or added to the solution polymerization reactors by coupling the reactors to heat exchangers. In the solution polymerization process, hydrogen may be utilized; however, it is not required in all solution polymerization processes.

Ziegler-Natta catalysts are commonly used to produce ethylene-based polymers in processes for polymerizing ethylene and, optionally, one or more alpha-olefin comonomers. In these polymerization processes comprising typical Ziegler-Natta catalysts, polymer average molecular weight decreases rapidly as polymerization temperature increases. However, high polymerization temperatures in solution polymerization processes increase production throughput and produce ethylene-based polymers with desired properties, such as superior optics and dart/tear balance. Increasing the molecular weight capability of a Ziegler-Natta catalyst may expand its ability to make new products and make it possible to operate at higher polymerization temperatures.

The present disclosure is directed to Ziegler-Natta-type procatalysts and catalysts comprising the procatalyst that exhibit increased molecular weight capability and exhibit the ability to increase the HDF of the ethylene-based polymer. A "procatalyst," as used herein, is a catalyst composition that is basically catalytically inactive before contacting with a cocatalyst and becomes catalytically active once contacting a cocatalyst. The procatalyst disclosed herein includes, in embodiments, a procatalyst comprising: a magnesium chloride catalyst support having a surface area of greater than or equal to <NUM><NUM>/g; a titanium containing component; a chlorinating agent; and a hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+, wherein the hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+ does not comprise vanadium. Embodiments also include a catalyst comprising the procatalyst and an aluminum alkyl cocatalyst, and include polymerization processes comprising the procatalyst and/or catalyst.

The MgCl<NUM> component may be prepared by selecting an organomagnesium compound or a complex including an organomagnesium compound and reacting the organomagnesium compound with a chloride compound, such as a metallic or non-metallic chloride, under conditions suitable to make the MgCl<NUM> component. Examples of organomagnesium compounds and/or complexes may include, but are not limited to, magnesium C<NUM>-C<NUM> alkyls and aryls, magnesium alkoxides and aryloxides, carboxylated magnesium alkoxides, and carboxylated magnesium aryloxides, or combinations of these. In some embodiments, the organomagnesium compound may include a magnesium C<NUM>-C<NUM> alkyl, magnesium C<NUM>-C<NUM> alkoxides, or combinations thereof. In some embodiments, the organomagnesium compound may be butyl ethyl magnesium.

In one or more embodiments, the MgCl<NUM> components include, for example, the reaction product of a chloride source with a hydrocarbon soluble hydrocarbylmagnesium compound or mixture of compounds. Exemplary organomagnesium compounds include di(C<NUM>-C<NUM>)alkylmagnesium or di(C<NUM>-C<NUM>)arylmagnesium compounds, particularly di(n-butyl)magnesium, di(sec-butyl)magnesium, diisopropylmagnesium, di-n-hexylmagnesium, isopropyl-n-butyl-magnesium, ethyl-n-hexylmagnesium, ethyl-n-butylmagnesium, di-n-octylmagnesium, and combinations thereof. Exemplary suitable magnesium diaryls include diphenylmagnesium, dibenzylmagnesium and ditolylmagnesium. The organomagnesium compounds may optionally be treated with an organoaluminum compound for improving solubility, reducing solution viscosity, or both improving solubility and reducing solution viscosity. Stabilizers, including those derived from substituted phenol compounds, may also be present. Additional suitable organomagnesium compounds include alkyl- and aryl- magnesium alkoxides, aryloxides and chlorides, as well as mixtures of the foregoing. Highly preferred organomagnesium compounds are the halogen-free organomagnesium compounds.

Among the chloride sources which can be employed in the preparation of MgCl<NUM> components for use herein include metallic chlorides and nonmetallic chlorides, including organo chlorides and hydrogen chloride. Suitable metallic chlorides, which can be employed herein, include a formula according to: MRy-aCla, wherein: M is a metal of Groups <NUM>, <NUM>, or <NUM> of the Periodic Table of Elements; R is a monovalent organic radical; y has a value corresponding to the valence of M, and a has a value from <NUM> to y.

In one or more embodiments, metallic chlorides may be chosen from alkylaluminum chlorides having the formula: AlR<NUM>-aCla, wherein: each R is independently (C<NUM>-C<NUM>)hydrocarbyl, preferably (C<NUM>-C<NUM>)alkyl, and a is a number from <NUM> to <NUM>. The akylaluminum chlorides may include, and are not limited to: ethylaluminum sesquichloride, diethylaluminum chloride, and ethylaluminum dichloride, with ethylaluminum dichloride being especially preferred. Alternatively, a metal chloride such as aluminum trichloride or a combination of aluminum trichloride with an alkyl aluminum chloride or a trialkyl aluminum compound may be suitably employed.

Suitable nonmetallic chlorides and organochlorides are represented by the formula R'Clr wherein R' is hydrogen or (C<NUM>-C<NUM>)hydrocarbyl or a non-metal such as Si, Ga or Ge; and subscript r is an integer from <NUM> to <NUM>. Particularly suitable chloride sources include, for example, hydrogen chloride and active organochlorides such as t-alkyl chlorides, sec-alkyl chlorides, allyl chlorides, and benzyl chlorides and other active hydrocarbyl chlorides wherein hydrocarbyl is as defined herein before. By an active organic chloride is meant a hydrocarbyl chloride that contains a labile chloride at least as active, that is, as easily lost to another compound, as the chloride of sec-butyl chloride, preferably as active as t-butyl chloride. In addition to the organic monochlorides, it is understood that organic dichlorides, trichlorides and other polychlorides that are active as defined herein before are also suitably employed. Examples of preferred chloride sources include hydrogen chloride, t-butyl chloride, t-amyl chloride, allyl chloride, benzyl chloride, crotyl chloride, and diphenylmethyl chloride. Most preferred are hydrogen chloride, t-butyl chloride, allyl chloride and benzyl chloride.

The organomagnesium halide can be preformed from the organomagnesium compound and the chloride source and stored for later use or it can be preformed in situ in which instance the procatalyst is preferably prepared by mixing in a suitable solvent or reaction medium (<NUM>) the organomagnesium component and (<NUM>) the chloride source, followed by the other procatalyst components.

In embodiments, the organomagnesium compound or complex may be soluble in a hydrocarbon diluent, such as an inert hydrocarbon diluent. Examples of hydrocarbon diluents may include, but are not limited to, liquefied ethane, propane, isobutane, n-butane, n-hexane, the various isomeric hexanes, isooctane, paraffinic mixtures of alkanes having from <NUM> to <NUM> carbon atoms, cyclohexane, methylcyclopentane, dimethylcyclohexane, dodecane, industrial solvents composed of saturated or aromatic hydrocarbons such as kerosene, naphthas, and combinations thereof. In some embodiments, the hydrocarbon diluent may be substantially free of any impurities, including alkynes, dienes, allenes, and any compounds containing one or more heteroatoms. As used herein, the term "substantially free" of a constituent means that a composition includes less than <NUM> wt. % of the constituent (e.g., impurity, compound, element, etc.). In some embodiments, the hydrocarbon diluent may have a boiling point in the range from about -<NUM> to about <NUM>. The hydrocarbon diluent may, in embodiments, include an isoparaffin solvent. Examples of isoparaffin solvents may include, but are not limited to, ISOPAR™ synthetic paraffin solvents available from ExxonMobile (e.g., ISOPAR™ E paraffin solvent), and special boiling point (SBP) solvents by Shell Chemicals (e.g., SBP <NUM>/<NUM> high purity de-aromatised hydrocarbon solvent). Other examples of hydrocarbon diluents may include methylcyclopentane, ethylbenzene, cumene, decalin, and combinations thereof.

The organomagnesium compound may be dispersed in the hydrocarbon diluent to form slurry. The chloride compound may be added to the slurry so that the organomagnesium compound is contacted with the chloride compound to produce the MgCl<NUM>. The chloride compound may be a metallic or non-metallic chloride. For example, in some embodiments, the chloride compound may be hydrochloride gas. In embodiments, the organomagnesium compound and the chloride compound may be contacted at a temperature of from -<NUM> to <NUM>, or from <NUM> to <NUM>. In some embodiments, heat removal is needed in order to control set reaction temperature within ±<NUM>, such as within ±<NUM>. In some embodiments, the amount of chloride source is controlled in order to achieve a target molar ratio of Cl to Mg in the resulting MgCl<NUM>. For example, the molar ratio of Cl to Mg can be from <NUM> to <NUM> for a chloride-deficient MgCl<NUM> support, or from <NUM> to <NUM> for a chloride-rich MgCl<NUM> support. In some embodiments, the slurry of organomagnesium compound and metallic or non-metallic chloride may be contacted for a time of from <NUM> hour to <NUM> hours, or from <NUM> hours to <NUM> hours. The concentration of the organomagnesium compound in the slurry (i.e., before the chloride compound is added to the slurry) may be sufficient so that when the chloride compound is added to the slurry, the resultant composition may include a concentration of magnesium of from <NUM> moles per liter (mol/L) to <NUM> mol/L.

The reaction of the metallic or non-metallic chloride with the organomagnesium compound produces the MgCl<NUM> component, which may be present in an MgCl<NUM> slurry that includes MgCl<NUM> particles dispersed in the hydrocarbon diluent. In some embodiments, the MgCl<NUM> slurry is prepared before being treated with other procatalyst component and is referred to herein as a "preformed MgCl<NUM> slurry. " In some embodiments, the MgCl<NUM> slurry may have a concentration of MgCl<NUM> of from <NUM> mol/L to <NUM> mol/L, or from <NUM> mol/L to <NUM> mol/L.

In embodiments, the MgCl<NUM> component may be formed by solution precipitation of a hydrocarbon soluble magnesium alkyl precursor with a non-metallic chloride. The magnesium alkyl precursor may, in some embodiments, be a magnesium C<NUM>-C<NUM> alkyl precursor. The non-metallic chloride may, in some embodiments, be hydrochloride gas. The hydrocarbon-soluble magnesium alkyl precursor and non-metallic chloride are added to a hydrocarbon diluent-such as, for example, the hydrocarbon diluents listed in this disclosure. The conditions for this precipitation process are the same as those previously disclosed for forming organomagnesium compounds.

The MgCl<NUM> component has, in embodiments, a surface area greater than or equal to <NUM> meter squared per gram (m<NUM>/g), such as a surface area greater than or equal to <NUM><NUM>/g, or greater than or equal to <NUM><NUM>/g, greater than or equal to <NUM><NUM>/g, greater than or equal to <NUM><NUM>/g. In some embodiments, the upper limit of the surface area of the MgCl<NUM> component is <NUM><NUM>/g.

Following the preparation of the MgCl<NUM> component, the MgCl<NUM> component may be contacted with a chlorinating agent. The chlorinating agent may have a structural formula A(Cl)x(R<NUM>)<NUM>-x or Si(Cl)y(R<NUM>)<NUM>-y, where R<NUM> is a (C<NUM>-C<NUM>) hydrocarbyl, x is <NUM>, <NUM>, or <NUM>, and y is <NUM>, <NUM>, <NUM>, or <NUM>. In some embodiments, A may be aluminum or boron. Examples of chlorinating agents may include, but are not limited to, aluminum trichloride, methyl aluminum dichloride, dimethylaluminum chloride, ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride, isobutylaluminum dichloride, diisobutylaluminum chloride, boron trichloride, phenylboron dichloride, dicyclohexylboron chloride, silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, chlorotrimethylsilane, ethyltrichlorosilane, dichlorodiethylsilane, chlorotriethylsilane, n-propyltrichlorosilane, dichlorodi(n-propyl)silane, chlorotri(n-propyl)silane, isopropyltrichlorosilane, dichlorodiisopropylsilane, chlorotriisopropylsilane, n-butyltrichlorosilane, dichlorodi(n-butyl)silane, chlorotri(n-butyl)silane, isobutyltrichlorosilane, dichlorodiisobutylsilane, chlorotriisobutylsilane, cyclopentyltrichlorosilane, dichlorodicylcopentylsilane, n-hexyltrichlorosilane, cyclohexyltrichlorosilane, dichlorodicyclohexylsilane, or combinations thereof. In some embodiments, the chlorinating agent is an aluminum alkyl chloride.

The MgCl<NUM> component may be contacted with the chlorinating agent under conditions sufficient to condition the MgCl<NUM> component. In embodiments, the MgCl<NUM> component may be contacted with the chlorinating agent at a temperature of from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>. The MgCl<NUM> component may be contacted with the chlorinating agent for a time of from <NUM> hours to <NUM> hours, such as from <NUM> hours to <NUM> hours, from <NUM> hours to <NUM> hours, or from <NUM> hours to <NUM> hours. Not intending to be bound by any theory, it is believed that conditioning the MgCl<NUM> component by contacting the MgCl<NUM> component with the chlorinating agent may facilitate or enhance adsorption of additional metals, such as, for example, a titanium species onto the MgCl<NUM> component. In some embodiments, the procatalyst may include a molar ratio of the chlorinating agent to the MgCl<NUM> component in the heterogeneous procatalyst of from <NUM>:<NUM> to <NUM>:<NUM>, such as from <NUM>:<NUM> to <NUM>:<NUM>, or from <NUM>:<NUM> to <NUM>:<NUM>.

The MgCl<NUM> component may additionally be contacted with a titanium containing component. The titanium containing component may be any titanium compound or complex. In some embodiments, the titanium containing component may include a titanium halide, a titanium alkoxide, or combinations thereof. For example, in embodiments, the titanium containing component may include, but is not limited to, titanium tetrachloride (TiCl<NUM>), titanium isopropoxide (TiPT), other titanium halide or titanium alkoxide, Ti(OR)<NUM> where R is C<NUM>-C<NUM> hydrocarbyl, or combinations thereof.

The MgCl<NUM> component may be contacted with the titanium containing component under conditions so that at least a portion of the titanium containing component is adsorbed onto the MgCl<NUM> component. For example, in embodiments, the MgCl<NUM> component may be contacted with the titanium containing component at a temperature of from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>. In some embodiments, the MgCl<NUM> component may be contacted with the titanium containing component at such temperature for a time of from <NUM> hours to <NUM> hours, such as from <NUM> hours to <NUM> hours, from <NUM> hours to <NUM> hours, or from <NUM> hours to <NUM> hours. In some embodiments, the MgCl<NUM> component is contacted with the titanium containing component after the MgCl<NUM> component is conditioned by the chlorinating agent. In other embodiments, the MgCl<NUM> component is contacted with the titanium containing component before the MgCl<NUM> component is contacted with the chlorinating agent. In yet other embodiments, the MgCl<NUM> component may be contacted with the chlorinating agent and the titanium containing component simultaneously by adding the chlorinating agent and the titanium containing component to the MgCl<NUM> slurry at the same time. The chlorinating agent may, in embodiments, react with the titanium containing component as well as the MgCl<NUM> component. For example, the chlorinating agent may react with the titanium in the titanium containing component to form a titanium chloride, such as, for example TiCl<NUM>, or TiCl<NUM>.

The procatalyst of embodiments also includes a hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+, where the transition metal compound does not comprise vanadium (hereinafter referred to as the "transition metal compound"). For example, the transition metal compound may be combined with the MgCl<NUM> component and, optionally, one or both of the titanium containing component and the chlorinating agent that are dispersed in the hydrocarbon diluent. The transition metal compound is a metal-ligand complex. Described herein is a transition metal compound havingthe structural formula (L)nM(XR<NUM>)b, where: M is a transition metal in an oxidation state of greater than or equal to <NUM>+, excluding vanadium; each L is a neutral ligand or (=O), each XR<NUM> is an anionic ligand in which X is a heteroatom and R<NUM> is (C<NUM>-C<NUM>) hydrocarbyl or (C<NUM>-C<NUM>) heterohydrocarbyl; n is <NUM> (zero), <NUM>, or <NUM>; and b is <NUM>, <NUM>, <NUM>, or <NUM>. The metal-ligand complex may be overall charge neutral. In embodiments, the metal-ligand complex is soluble in hydrocarbon solvents, such as the hydrocarbon diluents previously discussed in this disclosure. In some embodiments, one or more than one L may be a neutral ligand. In some embodiments, one or more than one L may include a neutral ligand comprising a nitrogen-containing or phosphorous-containing compound, such as, for example, ammonia, nitriles, pyridines, amines, phosphines, or combinations thereof. Examples of neutral ligands may include, but are not limited to, acetonitrile, pyridine, ammonia, ethylenediamine, triphenylphosphine, other neutral ligands, or combinations thereof. In some embodiments, one or more than one L may be an oxo group (=O). In some embodiments, X may be oxygen.

In embodiments, the metal-ligand complex is a metal alkoxide or metal halide having structural formula MXn-b(OR<NUM>)b, where M is a transition metal having an oxidation state "n" that is greater than or equal to <NUM>+ (not including vanadium), X is a halogen, b can be from <NUM> to n, and R<NUM> is (C<NUM>-C<NUM>) hydrocarbyl or (C<NUM>-C<NUM>) heterohydrocarbyl. In other embodiments, the metal ligand complex is a metal oxyalkoxide having structural formula M(=O)Xn-b (OR<NUM>)b, where M is the transition metal having an oxidation state n that is greater than or equal to <NUM>+ (not including vanadium), X is a halogen, b can be from <NUM> to n-<NUM>, and R<NUM> is (C<NUM>-C<NUM>) hydrocarbyl or (C<NUM>-C<NUM>) heterohydrocarbyl.

In some embodiments, the transition metal compound, such as M in the metal ligand previously discussed, may be a transition metal selected from the group consisting of molybdenum (Mo), niobium (Nb), tantalum (Ta), tungsten (W), iron (Fe), zirconium (Zr), chromium (Cr), manganese (Mn), zinc (Zn), and combinations thereof, each having an oxidation state of greater than or equal to <NUM>+. The transition metal compound does not comprise vanadium.

In embodiments, the transition metal compound may be combined with the slurry comprising the MgCl<NUM> component, before or after either of the titanium containing component and the chlorinating agent are dispersed in the slurry comprising the MgCl<NUM> component. In some embodiments, the transition metal compound may be combined with the slurry comprising the MgCl<NUM> component-that optionally comprises the titanium containing component and/or the chlorinating agent-and mixed for a period of from <NUM> minutes to <NUM> hours, such as from <NUM> minutes to <NUM> hours.

As discussed in this disclosure, the procatalyst comprises four components: (A) a titanium containing component; (B) a chlorinating agent; (C) a transition metal compound having an oxidation state greater than or equal to <NUM>+, excluding vanadium; and (D) an MgCl<NUM> component having a surface area or greater than or equal to <NUM><NUM>/g. In embodiments, components (A), (B), and (C) may be added to component (D) separately and in any order. In other embodiments, components (A), (B), and (C) may be added to component (D) in any combination and in any order, such as, for example, The addition sequence of components of (A), (B), and (C) to (D) may be adding (B), then adding (C), and then adding (A), or adding (B), then adding (A), and then adding (C). It should be understood that components (A), (B), and (C) may be added to component (D) in various other temporal combinations. Thus, in embodiments, at least one of components (A), (B), and (C) may be added to component (D) temporally separate from at least one other of components (A), (B), and (C).

Components (A), (B), (C), and (D) may be present in the procatalyst in various ratios. In embodiments a molar ratio of the transition metal present in the transition metal compound to the titanium present in the titanium containing compound (i.e., transition metal (mol)/Ti (mol)) is from <NUM> to <NUM>, such as from <NUM> to <NUM>, or from <NUM> to <NUM>. In embodiments, a molar ratio of the chlorinating agent to the titanium present in the titanium containing component (i.e., chlorinating agent (mol)/Ti (mol)) is from <NUM> to <NUM>, such as from <NUM> to <NUM>, or from <NUM> to <NUM>. In embodiments, a molar ratio of the MgCl<NUM> component to the titanium present in the titanium containing component (i.e., MgCl<NUM> (mol)/Ti (mol)) is from <NUM> to <NUM>, such as from <NUM> to <NUM>, or from <NUM> to <NUM>.

In embodiments, a cocatalyst may be combined with the procatalyst described herein to produce a catalyst system. The cocatalyst may include at least one organometallic compound such as an alkyl or haloalkyl of aluminum, an alkylaluminum halide, a Grignard reagent, an alkali metal aluminum hydride, an alkali metal borohydride, an alkali metal hydride, an alkaline earth metal hydride, or the like. In some embodiments, the cocatlyst is an alkyl of aluminum. The formation of the catalyst system from reaction of the procatalyst and the cocatalyst may be carried out in situ (in place), or just prior to entering the polymerization reactor. Thus, the combination of the procatalyst and the cocatalyst may occur under a wide variety of conditions. Such conditions may include, for example, contacting the procatalyst and cocatalyst under an inert atmosphere such as nitrogen, argon, or other inert gas at temperatures of from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> ° to <NUM>. In the preparation of the catalytic reaction product (i.e., catalyst system), it is not necessary to separate hydrocarbon soluble components from hydrocarbon insoluble components. In some embodiments, the procatalyst and cocatalyst may be introduced into a reactor simultaneously and contact each other inside the reactor. In some embodiments, the catalyst system may have a molar ratio of the cocatalyst to the titanium species in the titanium containing component of the procatalyst of from <NUM>:<NUM> to <NUM>:<NUM>, such as from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, or from <NUM>:<NUM> to <NUM>:<NUM>.

Once the catalyst system including the procatalyst and cocatalyst has been prepared, the catalyst system may be used in a polymerization or copolymerization process for polymerizing olefins. For example, in some embodiments, the catalyst system may be utilized in a polymerization or copolymerization process to make ethylene-based polymers, such as, for example, HDPE and linear low density polyethylene (LLDPE). In some embodiments, a polymerization or copolymerization process may include contacting ethylene monomers and optionally one or more α-olefin comonomers with the catalyst system comprising the procatalyst and, optionally, a cocatalyst to form an ethylene-based polymer. The olefin polymerization/copolymerization reaction may be conducted in a reaction medium. The reaction medium may be a hydrocarbon diluent, such as an isoparaffin, an aliphatic hydrocarbon, or any of the other hydrocarbon diluents previously described in this disclosure. The olefin polymerization/copolymerization process may include contacting the olefin or a combination of olefins with the reaction medium in the presence of the catalyst system, which includes the procatalyst composition and, optionally, the cocatalyst. Conditions for the polymerization may be any that are suitable, and a molecular weight regulator, such as, for example, hydrogen may also be present in the reaction vessel to suppress formation of undesirably high molecular weight polymers.

Any ethylene polymerization or copolymerization reaction process may be employed with the catalyst disclosed herein to produce the ethylene-based polymers. Such ethylene polymerization or copolymerization reaction processes may include, but are not limited to, slurry phase polymerization processes, solution phase polymerization processes, gas phase processes, and combinations thereof. The polymerization or copolymerization process may be performed within one or more conventional reactors, examples of which may include, but are not limited to, loop reactors, stirred tank reactors, batch reactors in parallel or in series, and/or any combinations thereof. In some embodiments, the polymerization process may be performed in two or more reactors in series, parallel, or combinations thereof. In other embodiments, the polymerization process may be conducted in a single reactor. The polymerization process may be a batch polymerization process or a continuous polymerization process. For example, in some embodiments, the polymerization process may be a batch polymerization process, which may be conducted in a stirred tank reactor. In some embodiments, the polymerization process may be continuous, such as a polymerization reaction conducted in a continuous solution polymerization reactor. In other embodiments, the polymerization process may include two or more polymerization steps. In these embodiments, the catalyst system comprising the procatalyst disclosed herein may be used for any one or a plurality of the polymerization steps.

The polymers produced from polymerization/copolymerization processes utilizing the procatalyst and/or catalyst disclosed herein may be homopolymers of C<NUM>-C<NUM> α-olefins, such as ethylene, propylene, or <NUM>-methyl-<NUM>-pentene. In some embodiments, the polymers formed in the presence of the procatalyst and/or catalyst disclosed herein may include interpolymers of ethylene or propylene with at least one or more α-olefins comonomers, C<NUM>-C<NUM> acetylenically unsaturated comonomers, and/or C<NUM>-C<NUM> diolefin comonomers. In some embodiments, the polymers may be ethylene-based polymers, such as interpolymers of ethylene with at least one of the above C<NUM>-C<NUM> α-olefins, diolefins, and/or acetylenically unsaturated comonomers in combination with other unsaturated comonomers. In some embodiments, the comonomer may be an α-olefin comonomer having no more than <NUM> carbon atoms. For example, in some embodiments, the α-olefin comonomer may have from <NUM> to <NUM> carbon atoms, from <NUM> to <NUM> carbon atoms, or from <NUM> to <NUM> carbon atoms. Exemplary α-olefin comonomers may include, but are not limited to, propylene, <NUM>-butene, <NUM>-pentene, <NUM>-hexene, <NUM>-heptene, <NUM>-octene, <NUM>-nonene, <NUM>-decene, and <NUM>-methyl-<NUM>-pentene. In some embodiments, the ethylene-based polymers may include an α-olefin comonomer selected from the group consisting of <NUM>-butene, <NUM>-hexene, and <NUM>-octene. In some embodiments, the ethylene-based polymers produced in the presence of the procatalyst and/or catalyst systems disclosed herein may be interpolymers of ethylene monomer units and comonomer units chosen from <NUM>-butene, <NUM>-hexene, <NUM>-octene, or combinations of these.

In some embodiments, a solution polymerization/copolymerization process is used. Polymerization is effected by adding a catalytic amount of the procatalyst and/or catalyst to a polymerization reactor containing the selected α-olefin monomers (e.g., ethylene and/or one or more α-olefin comonomers), or vice versa. The polymerization reactor may be maintained at a temperature of from <NUM> to <NUM>. For example, in some embodiments, the polymerization reactor may be maintained at temperatures of from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>. In some embodiments, the reactants, catalyst system, or both may have a residence time in the polymerization reactor of from <NUM> minutes to <NUM> minutes. In some embodiments, the residence time may be <NUM> minutes to <NUM> hours. Longer or shorter residence times may alternatively be employed.

In some embodiments, the polymerization/copolymerization process may be conducted at pressures that are relatively low, such as pressures of from <NUM> to <NUM>,<NUM> psig (<NUM> to <NUM> MPa), such as from <NUM> to <NUM>,<NUM> psig (<NUM> to <NUM> MPa), or from <NUM> to <NUM> psig (<NUM> to <NUM> MPa). However, polymerization/copolymerization in the presence of the procatalyst and/or catalyst described herein may be conducted at pressures from atmospheric pressure to pressures determined by the capabilities (e.g., pressure rating) of the polymerization equipment.

In some embodiments, the polymerization/copolymerization process may include a carrier, which may be an inert organic diluent, excess monomer, or both. Oversaturation of the carrier with the polymer may be generally avoided during the polymerization/copolymerization process. If such saturation of the carrier with the polymer occurs before the catalyst system becomes depleted, the full efficiency of the catalyst system may not be realized. In some embodiments, the polymerization/copolymerization process may be operated at conditions sufficient to maintain the amount of polymer in the carrier/diluent at a concentration less than an oversaturation concentration of the polymer. For example in some embodiments, the polymerization/copolymerization process may be operated at conditions sufficient to maintain the amount of the polymer in the carrier/diluent less than <NUM> weight percent (wt. %), based on the total weight of the reaction mixture. In some embodiments, the polymerization/copolymerization process may include mixing or stirring the reaction mixture to maintain temperature control and enhance the uniformity of the polymerization reaction throughout the polymerization zone. In some embodiments, such as with more rapid reactions with relatively active catalysts, the polymerization/copolymerization process may include refluxing monomer and diluent, if diluent is included, thereby removing at least some of the heat of reaction. In some embodiments, heat transfer equipment (e.g., heat exchangers, cooling jackets, or other heat transfer means) may be provided for removing at least a portion of the exothermic heat of polymerization.

In some embodiments, the reaction mixture added to the polymerization/copolymerization process may include an amount of ethylene monomer sufficient to maintain reactor stability and increase catalyst efficiency. In some embodiments, the reaction mixture may have a molar ratio of diluent to ethylene monomer of from <NUM>:<NUM> to <NUM>:<NUM>, such as from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, or from <NUM>:<NUM> to <NUM>:<NUM>. In some embodiments, a portion of excess ethylene monomer may be vented from the polymerization process to maintain the concentration of ethylene monomer in the reactor.

In some embodiments, the polymerization/copolymerization process may include contacting hydrogen gas with the reaction mixture during the reaction. The hydrogen gas may be operable to reduce formation of ultra-high molecular weight molecules of the ethylene-based polymer. In some embodiments, a concentration of the hydrogen gas in the reaction mixture may be maintained at from <NUM> to <NUM> mole of hydrogen per mole of monomer, where the monomer includes the ethylene monomer and any optional α-olefin comonomers. The hydrogen may be added to the polymerization reactor with a monomer stream, as a separate hydrogen feed stream, or both. The hydrogen may be added to the polymerization reactor before, during, and/or after addition of the monomer to the polymerization reactor. In some embodiments, the hydrogen may be added either before or during addition of the catalyst system.

The resulting ethylene-based polymer may be recovered from the polymerization mixture by driving off unreacted monomer, comonomer, diluent, or combinations thereof. In some embodiments, no further removal of impurities may be required. The resultant ethylene-based polymer may contain small amounts of catalyst residue. The resulting ethylene-based polymer may further be melt screened. For example, the ethylene-based polymer may be melted within an extruder and then passed through one or more active screens, positioned in series, with each active screen having a micron retention size of from <NUM> micrometers (µm) to about <NUM>, such as from <NUM> to about <NUM>, or from <NUM> to about <NUM>. During melt screening, the mass flux of the ethylene-based polymer may be from <NUM> to about <NUM> lb/hr/in<NUM> (<NUM> to about <NUM>/s/m<NUM>).

The resulting ethylene-based polymers produced with the procatalyst and/or catalyst disclosed herein may exhibit increased HDF compared to ethylene-based polymers that were not prepared in the presence of the procatalyst and/or catalyst disclosed herein. The HDF content may be determined in accordance with the test methods described in this disclosure. As used herein, the term "comparative polymer" refers to a polymer prepared by a comparative polymerization process in which an ethylene based polymer is polymerized in the presence of a comparative catalyst system. The comparative catalyst system comprises a comparative procatalyst composition in place of the procatalyst described herein, except that it does not contain the hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+.

In some embodiments, the ethylene-based polymers produced in the presence of the procatalyst and/or catalyst disclosed herein may have an HDF determined in accordance with the test methods described herein of at least <NUM>% greater than an HDF of a comparative polymer (HFD change). In some embodiments, the ethylene-based polymers produced by a process comprising the catalyst system disclosed herein may have a HDF of at least <NUM>% greater than the HDF of a comparative polymer (HFD change), such as at least <NUM>% greater than the HDF of a comparative polymer.

The efficiency of the catalyst in producing the ethylene-based polymer is, in embodiments, from <NUM> polymer/g Ti to <NUM> polymer/g Ti, such as from <NUM> polymer/g Ti to <NUM> polymer/g Ti, from <NUM> polymer/g Ti to <NUM> polymer/g Ti, from <NUM> polymer/g Ti to <NUM> polymer/g Ti, or from <NUM> polymer/g Ti to <NUM> polymer/g Ti.

The molecular weight of the ethylene-based polymer produced according to embodiments, as measured by gel permeation chromatography (GPC). In some embodiments, the ethylene-based polymers produced in the presence of the procatalyst and/or catalyst disclosed herein may have a Mw determined in accordance with the test methods described herein of at least <NUM>% greater than a Mw of a comparative polymer (Mw change), or at least <NUM>%, or at least <NUM>%.

The ethylene-based polymers produced in the presence of the procatalyst and/or catalyst disclosed herein may further include additional components such as other polymers and/or additives. Examples of additives may include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, and combinations thereof. In some embodiments, antioxidants, such as IRGAFOS™ <NUM> and IRGANOX™ <NUM> available from Ciba Geigy, may be used to protect the ethylene-based polymer compositions from thermal and/or oxidative degradation. The ethylene-based polymers may contain any amount of the additives. For example, in some embodiments, the ethylene-based polymers may include from <NUM> wt. % to <NUM> wt. %, such as from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or even from <NUM> wt. % to <NUM> wt. % additives based on the total weight of the ethylene-based polymer compositions including such additives.

The ethylene-based polymers produced in the presence of the catalyst systems disclosed herein may be included in a wide variety of products including, in embodiments, LLDPE, but also high density polyethylenes (HDPE), plastomers, medium density polyethylenes, and polypropylene copolymers. For these and other applications, articles may be prepared showing enhanced overall quality due to the increased average molecular weight and high-density fraction of the ethylene-based polymer. Useful forming operations for the polymers may include, but are not limited to, film, sheet, pipe, and fiber extrusion and co-extrusion as well as blow molding, injection molding, and rotary molding may be pursued. Films may include blown or cast films formed by co-extrusion or by lamination and may be useful as shrink film, cling film, stretch film, sealing film, oriented film, snack packaging, heavy duty bags, grocery sacks, baked and frozen food packaging, medical packaging, industrial liners, agricultural film applications, and membranes, for example, in food-contact and non-food-contact applications. Fibers may include melt spinning, solution spinning, and melt blown fiber operations for use in woven and non-woven form to make filters, diaper fabrics, medical garments, and geotextiles. Extruded articles may include medical tubing, wire and cable coatings, geomembranes, and pond liners. Molded articles may include single and multi-layered constructions in the form of bottles, tanks, large hollow articles, rigid food containers, and toys.

Density is measure in accordance with ASTM D792 and reported in grams/cubic centimeter (g/cc or g/cm<NUM>).

Melt index (I<NUM>), is measured in accordance with ASTM D1238, under conditions of <NUM> and <NUM> of load. Melt Flow Index (I<NUM>) was obtained with a CEAST <NUM> or an Instron MF20 instrument. The instruments followed ASTM D1238, Methods E and N. The melt index (I<NUM>) is reported in grams eluted per <NUM> minutes (g/<NUM>). The melt index I<NUM> was used for polymer characterization. A higher I<NUM> value may generally correlates to a lower Mw.

The weight average molecular weight (Mw) of the ethylene-based polymers are measured with GPC. The polymer sample is dissolved by adding the polymer sample to <NUM>,<NUM>,<NUM>-trichlorobenzene (TCB) at a concentration of <NUM>/mL and heating the mixture for <NUM> minutes at <NUM>. The solution includes <NUM> parts per million by weight (ppmw) of butylated hydroxytoluene (BHT) to stabilize the solution. Each sample was then diluted to <NUM> milligram per milliliter (mg/mL) immediately before the injection of a <NUM> microliter (µL) aliquot of the sample. The chromatograph was equipped with two Polymer Labs PLgel <NUM> MIXED-B columns (<NUM> millimeters (mm) x <NUM>), which are operated at a flow rate of <NUM>/minute and a temperature of <NUM>. Sample detection is performed with a PolymerChar IR4 detector in concentration mode. A conventional calibration of narrow polystyrene (PS) standards was utilized with apparent units adjusted to homo-polyethylene (PE) using known Mark-Houwink coefficients for PS and PE in TCB at this temperature.

Improved comonomer content distribution (iCCD) analysis was performed with a Crystallization Elution Fractionation (CEF) instrument (PolymerChar, Spain) equipped with an IR-<NUM> detector (PolymerChar, Spain) and two angle light scattering detectors (e.g., Model <NUM> detectors from Precision Detectors, currently Agilent Technologies). A guard column that includes <NUM>-<NUM> micron glass (MoSCi Corporation, USA) packed into a <NUM> centimeter (cm) (length) by ¼ inch (<NUM>) inner diameter (ID) stainless column is installed just before IR-<NUM> detector in the detector oven. Ortho-dichlorobenzene (oDCB, <NUM>% anhydrous grade or technical grade) is distilled before use. Silica gel <NUM> (Aldrich, high purity grade, <NUM>-<NUM> mesh) is used to further dry oDCB. The silica gel is dried in a vacuum oven at <NUM> for about two hours before use. The silica gel <NUM> is packed into three <NUM> x <NUM> GPC size stainless steel columns. The Silica gel <NUM> columns are installed at the inlet of the pump of the CEF instrument. CEF instrument is equipped with an autosampler with N<NUM> purging capability. oDBC is sparged with dried nitrogen (N<NUM>) continuously and for at least one hour before use.

Sample preparation is done with an autosampler at <NUM>/ml (unless otherwise specified) under shaking at <NUM> for <NUM> hours. The injection volume is <NUM>µl. The temperature profile of iCCD is: stabilization at <NUM>, crystallization at a cooling rate of <NUM>/min from <NUM> to <NUM>, the thermal equilibrium at <NUM> for <NUM> minutes (including Soluble Fraction Elution Time being set as <NUM> minutes), elution at a heating rate of <NUM>/min from <NUM> to <NUM>. The flow rate during crystallization is <NUM>/min. The flow rate during elution is <NUM>/min. The data is collected at one data point/second. The iCCD column is packed with Bright 7GNM8-NiS (Bright 7GNM8-NiS) in a <NUM> (length) by ¼ inch (<NUM>) ID stainless tubing according to the reference (<CIT>). Column temperature calibration is performed by with a mixture of the Reference Material Linear homopolymer polyethylene <NUM>-<NUM> (<NUM>/ml) and Eicosane (<NUM>/ml) in oDCB. The molecular weight of polymer and the molecular weight of the polymer fractions was determined directly from LS detector (<NUM> degree angle) and concentration detector (IR-<NUM>) according Rayleigh-Gans-Debye approximation (Striegel and Yau, Modern Size Exclusion Liquid Chromatogram, Page <NUM> and Page <NUM>) by assuming the form factor of <NUM> and all the virial coefficients equal to zero. Baselines are subtracted from LS, and concentration detector chromatograms. For the whole resin, integration windows are set to integrate all the chromatograms in the elution temperature (temperature calibration is specified above) range from <NUM> to <NUM>. The weight percentage of the high density fraction of the resin (HDF) is defined by the following Equation <NUM> (EQU. <NUM>): <MAT>.

Catalyst efficiency is calculated based on the amount of ethylene consumed during the polymerization per g of Ti used in the procatalyst composition (g/g Ti).

Embodiments of the present disclosure will be further clarified by the following examples.

MgCl<NUM> slurry is prepared according to description in the "Magnesium halide support" section in <CIT>.

All procatalyst preparations were performed within a nitrogen-purged glovebox. Preparations involved sequential room temperature additions (with stirring) of stock solutions of procatalyst components in hexane (<NUM>) to a MgCl<NUM> slurry (<NUM> in Isopar-E). Procatalyst components were added to MgCl<NUM> in the order of Et<NUM>AlCl, transition metal component Reagent X (if any), and Ti compounds (TiCl<NUM> or TiPt). The reaction time for each reaction step is about <NUM> hours. For example, procatalyst (<NUM> Al; <NUM> Ti; <NUM> Zn) in Example <NUM> was prepared by adding EtAlCl<NUM> to MgCl<NUM> slurry. After stirring at room temperature for <NUM> hours, a hexane solution of zinc <NUM>-ethylhexanoate (Zn(EHA)<NUM>; ~<NUM>% in mineral spirit) obtained from STREM Chemical, Inc. After the reaction was allowed to proceed at room temperature with agitation for another <NUM> hours, a TiCl<NUM> solution was introduced to the mixture and the content was stirred overnight at room temperature to yield the procatalyst. The molar ratio of the individual reagents (relative to <NUM> equivalents of Mg) are listed in following tables.

Solution batch ethylene/<NUM>-octene polymerizations were carried out in a stirred one-gallon reactor, which was charged with <NUM> of <NUM>-octene (C<NUM>) and <NUM> of Isopar-E. The reactor was heated to <NUM> and then saturated with ethylene (<NUM> psig) in the presence of hydrogen (<NUM> mmol). The catalyst premix and cocatalyst (triethylaluminum, TEA; TEA/Ti = <NUM> for Table <NUM> and TEA/Ti = <NUM> for Table <NUM>) were mixed briefly (<NUM>-<NUM>) in an overhead shot tank before injection to the reactor. The polymerization was allowed to proceed for <NUM> minutes during which time the ethylene pressure was maintained via on-demand ethylene feed. After which time the bottom valve was opened and the contents transferred to a glass kettle and mixed with an antioxidant solution (<NUM> of toluene containing <NUM> IRGAFOS <NUM> (manufactured by BASF Corporation) and <NUM> of IRGANOX <NUM> (manufactured by BASF Corporation)). The contents were poured onto a Mylar lined pan, cooled, and allowed to stand in a hood overnight. The resin was then dried in a vacuum oven at <NUM> for <NUM> hr. Catalyst loadings typically ranged from <NUM>-<NUM> micromoles Ti.

As shown in Table <NUM> above, many transition metal compounds having an oxidation state of less than or equal to <NUM>+ caused polymer molecular weight and HDF content to decrease (see Comp. <NUM> vs. Comp. <NUM> - <NUM>). In contrast, compounds with oxidation state of <NUM> or higher, i.e., Mo(OEt)<NUM>, Nb(OnBu)<NUM> and Ta(OnBu)<NUM>, increased polymer molecular weight (c. <NUM> -<NUM> and Comp. <NUM>) and HDF content.

Claim 1:
A procatalyst, comprising:
a preformed magnesium chloride catalyst support having a surface area of greater than or equal to <NUM><NUM>/g;
a titanium containing component;
a chlorinating agent; and
a hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+, wherein the hydrocarbon soluble transition metal compound having an oxidation state of greater than or equal to <NUM>+ does not comprise vanadium;
wherein the transition metal compound is a metal-ligand complex and
(a) the metal-ligand complex is a metal alkoxide or metal halide having structural formula MXn-b(OR<NUM>)b, where M is a transition metal having an oxidation state "n" that is greater than or equal to <NUM>+ (not including vanadium), X is a halogen, b is from <NUM> to n, and R<NUM> is (C<NUM>-C<NUM>) hydrocarbyl or (C<NUM>-C<NUM>) heterohydrocarbyl; or
(b) the metal ligand complex is a metal oxyalkoxide having structural formula M(=O)Xn-b(OR<NUM>)b, where M is the transition metal having an oxidation state n that is greater than or equal to <NUM>+ (not including vanadium), X is a halogen, b is from <NUM> to n-<NUM>, and R<NUM> is (C<NUM>-C<NUM>) hydrocarbyl or (C<NUM>-C<NUM>) heterohydrocarbyl.