Symmetric hafnium metallocene for producing polymers having a broad orthogonal composition distribution

Abstract

Embodiments of the present disclosure relate to a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand, a composition comprising the symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand, and a method of using the composition comprising the symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to metallocenes, methods for producing the same and using the same, and polyolefins produced thereby.

Background Art

[0002] Metallocenes can be used in various applications including polymerization catalysts. Polymers can be utilized in particular for several articles including films and the like. Polymers can be formed by reacting one or more monomers in a polymerization reaction. In the art, there continues to be a focus on developing novel and improved materials and / or processes that can be utilized in growth media.

Summary of the Invention

[0003] The present disclosure provides various embodiments including the following.

[0004] A symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand represented by Structure (I),

[0005]

Chemical Formula

[0006] A metallocene catalyst composition comprising a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand and an activator.

[0007] A method for producing a metallocene catalyst composition, the method comprising contacting a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand with an activator.

[0008] A method for producing a polyolefin polymer, comprising polymerizing at least one olefin monomer with a metallocene catalyst composition to produce a polyolefin polymer.

Brief Description of the Drawings

[0009]

Figure 1

Mode for Carrying Out the Invention

[0010] Symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands are discussed herein. Advantageously, these symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands can be utilized, for example, to produce catalyst compositions. These catalyst compositions can be utilized to produce polymers having an improved, i.e., larger, molecular weight comonomer distribution index (MWCDI) compared to other polymers produced from other metallocenes. These polymers are particularly desirable for many applications including films. Thus, it is advantageous to provide an improved MWCDI. In addition, these catalyst compositions can be utilized to produce polymers having an improved, i.e., larger, comonomer incorporation (C6 wt%) compared to polymers produced from other metallocenes.

[0011] Symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands can also be used to provide polymers having an improved inverse short chain branch distribution, as discussed herein. A defining characteristic of polymers such as poly(ethylene-co-1-alkene) resins is the short chain branch distribution (SCBD), or comonomer distribution. For improved product performance in many applications, it is desirable to have an inverse SCBD or inverse comonomer distribution in which the weight percent (wt%) of comonomer in the polymer increases as the molecular weight (MW) of the polymer chains increases. This is also referred to as a polymer having a broad orthogonal composition distribution (BOCD). Such distributions are typically obtained using a dual reactor configuration and single or dual catalyst processes. In a dual reactor process, a single catalyst can be used to produce a high MW low density component (having a higher comonomer wt%) and a low MW high density (lower comonomer wt%) component in separate reactors through independent process control within the two reactors. The result is a bimodal resin having an inverse SCBD. In the case of a dual catalyst single reactor process, one catalyst produces a high MW low density component while the other forms a low MW high density component, resulting in a bimodal product having an inverse SCBD.

[0012] A more desirable method for obtaining polymers having an inverse SCBD is to use a single catalyst capable of producing such BOCD resins in a single reactor. The symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands of the present disclosure, as discussed herein, are capable of producing in a single reactor polymers having an improved BOCD resin, particularly polymers having a measurable greater tendency for the comonomer to chain to the higher MW fraction and maintaining significant BOCD characteristics over a wide range of process conditions. In addition, there is a need in the industry for low melt index resins having a broad molecular weight distribution and high BOCD compositions for films and other applications. Without being bound by theory, the iso-butyl groups of the symmetric hafnium metallocenes of the present disclosure are primary C(sp 3)-Increase the number of -H bonds, thereby increasing the frequency of this reaction, enhancing the tendency towards multi-site nature of the symmetric hafnium metallocene catalyst, and generating a polymer having BOCD.

[0013] A symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand can be represented by structure (I).

[0014] [Chemical formula] Each X is, independently, a leaving group. As shown in structure (I), the upper cyclopentadienyl ring is substituted with an isobutyl ligand, and the lower cyclopentadienyl ring is substituted with another isobutyl ligand. Since one of both cyclopentadienyl rings is substituted with each isobutyl ligand, the metallocene can be referred to as a symmetric metallocene.

[0015] Embodiments of the present disclosure provide that X is a leaving group. One or more embodiments provide that X is selected from alkyl, aryl, hydride, and halogen. One or more embodiments provide that X is selected from halogen, (C1-C5) alkyl, CH2SiMe3, and benzyl. One or more embodiments provide that X is selected from alkyl and halogen. One or more embodiments provide that X is Cl. One or more embodiments provide that X is methyl.

[0016] Examples of X include halide ions, hydrides, (C1-C 12 ) alkyl, (C2-C 12 ) alkenyl, (C6-C 12 ) aryl, (C7-C 20 ) alkylaryl, (C1-C 12 ) alkoxy, (C6-C 16 ) aryloxy, (C7-C8) alkylaryloxy, (C1-C 12 fluoroalkyl, (C6-C 12 ) fluoroaryl, and (C1-C12 ) Heteroatom-containing hydrocarbons and their substituted derivatives are included. One or more embodiments include hydrides, halogen ions, (C1-C6) alkyl, (C2-C6) alkenyl, (C7-C 18 alkylaryl, (C1-C6) alkoxy, (C6-C 14 ) aryloxy, (C7-C 16 ) alkylaryloxy, (C1-C6) alkyl carboxylate, (C1-C6) fluorinated alkyl carboxylate, (C6-C 12 ) aryl carboxylate (C7-C 18 ) alkylaryl carboxylate, (C1-C6) fluoroalkyl, (C2-C6) fluoroalkenyl, and (C7-C 18 ) fluoroalkylaryl. One or more embodiments include hydrides, chlorides, fluorides, methyl, phenyl, phenoxy, benzyloxy, tosyl, fluoromethyl, and fluorophenyl. One or more embodiments include (C1-C 12 ) alkyl, (C2-C 12 ) alkenyl, (C6-C 12 ) aryl, (C7-C 20 ) alkylaryl, substituted (C1-C 12 ) alkyl, substituted (C6-C 12 ) aryl, substituted (C7-C 20 ) alkylaryl, and (C1-C 12 ) heteroatom-containing alkyl, (C1-C 12 ) heteroatom-containing aryl, and (C1-C 12 ) heteroatom-containing alkylaryl. One or more embodiments include chlorides, fluorides, (C1-C6) alkyl, (C2-C6) alkenyl, (C7-C 18 ) alkylaryl, halogenated (C1-C6) alkyl, halogenated (C2-C6) alkenyl, and halogenated (C7-C 18)It includes alkylaryl. One or more embodiments include fluoride, methyl, ethyl, propyl, phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, fluoromethyl (mono-, di-, and trifluoromethyl), and fluorophenyl (mono-, di-, tri-, tetra-, and pentafluorophenyl).

[0017] Other non-limiting examples of the X group include amines, phosphines, ethers, carboxylates, dienes, hydrocarbon groups having 1 to 20 carbon atoms, fluorinated hydrocarbon groups such as -C6F5 (pentafluorophenyl), fluorinated alkyl carboxylates such as CF3C(O)O-, hydrides, halogen ions, and combinations thereof. Other examples of the X ligand include, in particular, alkyl groups such as cyclobutyl, cyclohexyl, methyl, heptyl, tolyl, trifluoromethyl, tetramethylene, pentamethylene, methylidene, methoxy, ethoxy, propoxy, phenoxy, bis(N-methylanilide), dimethylamide, and dimethylphosphide groups. In one embodiment, two or more Xs form part of a fused ring or ring system. In one or more embodiments, X is a chloride ion, bromide ion, (C1-C 10 )alkyl, (C2-C 12 )alkenyl, carboxylate, acetylacetonate, and alkoxide, and can be a leaving group selected from the group consisting of. In one or more embodiments, X is methyl.

[0018] The isobutylcyclopentadienyl ligand symmetric hafnium metallocene discussed herein can be produced by contacting a hafnium complex with an alkali metal complex to produce the isobutylcyclopentadienyl ligand symmetric hafnium metallocene. The symmetric hafnium metallocene discussed herein can be produced by a process using, for example, conventional solvents, reaction conditions, reaction times, and isolation procedures utilized to produce known metallocenes.

[0019] The alkali metal complex can be represented by the following structure,

[0020]

Chem.

[0021] One or more embodiments provide that the hafnium complex can be hafnium tetrachloride.

[0022] One or more embodiments provide a method for producing a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand (e.g., in the formula, each X is Cl), which comprises contacting a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand with 2 molar equivalents of an organomagnesium halide of the formula RMg (halide) or 1 molar equivalent of R2Mg (wherein R is (C1-C5) alkyl, CH2SiMe3, or benzyl, and the halide is Cl or Br) to produce a symmetric hafnium metallocene of structure (I), and each X is halogen, (C1-C5) alkyl, CH2SiMe3, or benzyl. One or more embodiments provide that X is (C1-C5) alkyl, CH2SiMe3, or benzyl. One or more embodiments provide that X is Cl or CH3. As used herein, all references to the Periodic Table of the Elements and its groups are to the NEW NOTATION published in HAWLEY’S CONDENSED CHEMICAL DICTIONARY, Thirteenth Edition, John Wiley & Sons, Inc., (1997) (reproduced with permission of IUPAC), unless otherwise indicated by a reference to the previous IUPAC system denoted by Roman numerals (which is also shown in the same way), or unless otherwise specified.

[0023] As used herein, "alkyl" includes straight-chain, branched-chain, and cyclic paraffin groups lacking one hydrogen. Thus, for example, CH3 ("methyl") and CH2CH3 ("ethyl") are examples of alkyl.

[0024] As used herein, "alkenyl" includes linear, branched, and cyclic olefinic groups lacking one hydrogen. An alkynyl group includes linear, branched, and cyclic acetylene groups lacking one hydrogen group.

[0025] As used herein, the term "aryl" includes phenyl, naphthyl, pyridyl, and other groups having a ring structure characteristic of benzene, naphthylene, phenanthrene, anthracene, etc. The "aryl" group is C6-C 20 It is understood that it can be an aryl group. For example, the C6H5 aromatic structure is "phenyl", and the C6H4 aromatic structure is "phenylene". An "arylalkyl" group is an alkyl group having an aryl group pendant therefrom. An "aralkyl" group is C7-C 20 It is understood that it can be an aralkyl group. "Alkylaryl" is an aryl group having one or more alkyl groups pendant therefrom.

[0026] As used herein, "alkylene" includes linear, branched, and cyclic hydrocarbon groups lacking two hydrogens. Thus, CH2 ("methylene") and CH2CH2 ("ethylene") are examples of alkylene groups. Other groups lacking two hydrogens include "arylene" and "alkenylene".

[0027] As used herein, the term "heteroatom" includes any atom selected from the group consisting of B, Al, Si, Ge, N, P, O, and S. A "heteroatom-containing group" is a hydrocarbon group containing a heteroatom and, in certain embodiments, may contain one or more of the same or different heteroatoms and 1 to 3 heteroatoms. Non-limiting examples of heteroatom-containing groups include imine, amine, oxide, phosphine, ether, ketone, oxazoline complex cyclic compounds, oxazoline, and thioether groups (monoradicals and diradicals).

[0028] As used herein, the term "substituted" means that one or more hydrogen atoms in the parent structure are independently replaced by a substituent atom or group.

[0029] The symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands discussed herein can be utilized to produce catalyst compositions. These compositions include a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand and an activator as discussed herein. One or more embodiments provide that the activator is an alkylaluminoxane such as methylaluminoxane. As used herein, "activator" refers to any compound or combination of compounds, supported or unsupported, that can activate a complex or catalyst component, for example, by generating a cationic species of the catalyst component. For example, this can involve the extraction of at least one leaving group from the metal center of a complex / catalyst component, such as a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand of structure (I), for example, the "X" group described herein. The activator is sometimes referred to as a "cocatalyst". As used herein, "leaving group" refers to one or more chemical moieties that are bonded to a metal atom and can be extracted by an activator, thus being able to generate a species active towards olefin polymerization. Various catalyst compositions, such as olefin polymerization catalyst compositions, are known in the art, and various known catalyst composition components may be utilized in various amounts and for various applications.

[0030] The symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands discussed herein can be utilized to produce spray-dried compositions. As used herein, "spray-dried composition" refers to a composition containing several components that have undergone a spray-drying process. Various spray-drying processes are known in the art and are suitable for forming the spray-dried compositions disclosed herein. One or more embodiments provide that the spray-dried composition contains a trim composition.

[0031] In one or more embodiments, the spray drying process may include atomizing a composition comprising a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand discussed herein. Some other known components may be utilized in the spray drying process. For example, an atomizer such as an atomizing nozzle or a centrifugal high-speed disk may be used to create a spray or dispersion of droplets of the composition. Next, the droplets of the composition may be rapidly dried by contacting them with an inert drying gas. The inert drying gas may be any gas that is non-reactive under the conditions employed during atomization, such as nitrogen. The inert drying gas may contact the composition with an atomizer that continuously generates a stream of droplets. The dried particles of the composition may be captured from the process in a separator such as a cyclone that can separate solids formed from a gaseous mixture of the drying gas, solvent, and other volatile components.

[0032] The spray-dried composition may have, for example, the form of a free-flowing powder. After the spray drying process, a slurry may be formed using the spray-dried composition and some known components. The spray-dried composition may be utilized with a diluent to form, for example, a slurry suitable for use in olefin polymerization. In one or more embodiments, the slurry may be combined with one or more additional catalysts or other known components before being delivered to the polymerization reactor.

[0033] In one or more embodiments, the spray-dried composition may be formed by contacting spray-dried activator particles, such as spray-dried MAO, with a solution of a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand as discussed herein. Such solutions can typically be prepared, for example, in an inert hydrocarbon solvent and may sometimes be referred to as trim solutions. Such spray-dried compositions, which consist of contacting a trim solution of a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand with spray-dried activator particles, such as spray-dried MAO, may be prepared in situ in a feed line leading to a gas-phase polymerization reactor by contacting the trim solution with a slurry of the spray-dried activator particles, typically a slurry in mineral oil. Alternatively, the spray-dried composition may be formed by contacting a slurry of the spray-dried activator particles (e.g., a mineral oil slurry of the spray-dried activator particles) with a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand as discussed herein.

[0034] Various spray-drying conditions may be utilized for different applications. For example, the spray-drying process may use a drying temperature of from 115 °C to 185 °C. Other drying temperatures are possible and the temperature may depend on the metallocene and activator particles. Different particle sizes may be obtained by using orifices of various sizes of the atomizing nozzles employed during the spray-drying process. Alternatively, in other types of atomizers, such as disks, different particle sizes may be obtained by adjusting the rotational speed, disk size, and number / size of the holes. One or more embodiments provide that a filler may be utilized in the spray-drying process. Different amounts of additives can be utilized for various applications.

[0035] Symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands discussed herein, such as catalyst compositions such as spray-dried hafnium metallocene compositions, may be utilized to produce polymers. For example, symmetric hafnium metallocenes having isobutylcyclopentadienyl ligands may be activated, i.e., a catalyst may be produced using an activator. One or more embodiments provide that the spray-dried composition contains an activator. As used herein, an "activator" refers to any supported or unsupported compound or combination of compounds that can activate a complex or catalyst component, for example, by generating a cationic species of the catalyst component to provide a catalyst. The activator is sometimes referred to as a "cocatalyst". The activator can include a Lewis acid or a non-coordinating ionic activator or an ionizing activator, or any other compound including a Lewis base, an aluminum alkyl, and / or a conventional type cocatalyst. Particularly, methylaluminoxane (MAO) and modified methylaluminoxane (MMAO) are mentioned as activators. One or more embodiments provide that the activator is methylaluminoxane. Activation conditions are well known in the art. Known activation conditions can be utilized.

[0036] The molar ratio of the metal in the activator, such as aluminum, to hafnium in the symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand may be from 1500:1 to 0.5:1, from 300:1 to 1:1, or from 150:1 to 1:1. One or more embodiments provide that the molar ratio of the activator to hafnium in the symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand is at least 75:1. One or more embodiments provide that the molar ratio of the activator to hafnium in the symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand is at least 100:1. One or more embodiments provide that the molar ratio of the activator to hafnium in the symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand is at least 150:1.

[0037] The symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand discussed in this specification, as well as several other components, can be supported on the same or separate carriers, or can be used in a form in which one or more components are not supported. The use of a carrier can be achieved by any technique used in the art. One or more embodiments provide that a spray drying process is utilized. For example, a symmetric metallocene having an isobutylcyclopentadienyl ligand in an inert solvent can be contacted with a supported or spray dried activator (or a slurry thereof) to obtain a spray dried metallocene catalyst composition. Alternatively, the supported symmetric hafnium metallocene of the present disclosure, as well as several other components, can be formed by drying a slurry of the components under vacuum or reduced pressure. The carrier may be functionalized. One or more embodiments provide that the spray dried composition comprises a carrier.

[0038] The "carrier", which may also be referred to as a "support", refers to any carrier material including a porous carrier material such as, for example, talc, inorganic oxides, and inorganic chlorides. Other carrier materials include resin carrier materials such as functionalized or crosslinked organic carriers such as polystyrene, polystyrene divinylbenzene polyolefins, or polymeric compounds, zeolites, clays, or any other organic or inorganic carrier material, or mixtures thereof.

[0039] Examples of the carrier material include inorganic oxides containing metal oxides of Groups 2, 3, 4, 5, 13, or 14. Some preferred carriers include silica, fumed silica, alumina, silica-alumina, and mixtures thereof. Some other carriers include magnesia, titania, zirconia, magnesium chloride, montmorillonite, phyllosilicate, zeolite, talc, clay, etc. Also, combinations of these carrier materials, such as silica-chromium, silica-alumina, silica-titania, etc. can be used. One or more embodiments provide that the carrier is silica. One or more embodiments provide that the carrier is hydrophobic fumed silica. One or more embodiments provide that the carrier is dehydrated silica. Further carrier materials include porous acrylic polymers, nanocomposites, aerogels, spherulites, and polymer beads. Further carrier materials may include porous acrylic polymers, nanocomposites, aerogels, spherulites, and polymer beads. An example of the carrier is fumed silica available under the trade name Cabosil™ TS-610, or other TS or TG series carriers available from Cabot Corporation. Fumed silica is typically silica having particles sized 7 - 30 nanometers that have been treated with dimethylsilyl dichloride such that most of the surface hydroxyl groups are capped.

[0040] A symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand described herein, for example, can be contacted with an olefin under polymerization conditions with a catalyst composition / spray-dried composition to produce a polymer, such as a polyolefin polymer. The polymerization process can be a suspension polymerization process, a slurry polymerization process, and / or a gas phase polymerization process. The polymerization process can use known equipment and reaction conditions, such as known polymerization conditions. The polymerization process is not limited to any particular type of polymerization system. The polymer can be utilized in many articles such as films, fibers, nonwovens and / or woven fabrics, extruded articles, and / or molded articles.

[0041] One or more embodiments provide that the polymer is manufactured using a gas-phase reactor system. One or more embodiments provide that, for example, as opposed to a series of reactors, a single gas-phase reactor is utilized. In other words, the polymerization reaction occurs only within one reactor. For example, the polymer can be manufactured using a fluidized bed reactor. Gas-phase reactors are known, and known components may be utilized in a fluidized bed reactor.

[0042] As used herein, an “olefin,” which may be referred to as an “alkene,” refers to a straight-chain, branched-chain, or cyclic compound that contains carbon and hydrogen and has at least one double bond. As used herein, when a polyolefin, polymer, and / or copolymer is said to contain an olefin, for example, be made from an olefin, the olefin present in such a polymer or copolymer is a polymerized form of the olefin. For example, when a copolymer is said to have an ethylene content of 75 wt% to 95 wt%, the polymer units in the copolymer are derived from ethylene in the polymerization reaction, and it is understood that the derived units are present at 75 wt% to 95 wt% based on the total weight of the polymer. A higher α-olefin means an α-olefin having 3 or more carbon atoms.

[0043] The polyolefins produced using the compositions discussed herein can be produced from olefin monomers such as ethylene (i.e., polyethylene) or propylene (i.e., polypropylene), among those provided herein, and the polyolefins are homopolymers produced from only olefin monomers (e.g., produced from 100 wt% ethylene or 100 wt% propylene). Alternatively, examples of polyolefins produced using the compositions discussed herein include polymers produced from olefin monomers such as ethylene, i.e., polyethylene, and linear or branched higher α-olefin monomers containing 3 to 20 carbon atoms. Examples of higher α-olefin monomers include, but are not limited to, propylene, butene, pentene, 1-hexene, and 1-octene. Examples of polyolefins include, in particular, ethylene-based polymers having at least 50 wt% ethylene, such as ethylene-1-butene, ethylene-1-hexene, and ethylene-1-octene copolymers. One or more embodiments provide that the polymer can contain 50 to 99.9 wt% of units derived from ethylene, based on the total weight of the polymer. All individual values and subranges from 50 to 99.9 wt% are included. For example, the polymer can contain units derived from ethylene from a lower limit of 50, 60, 70, 80, or 90 wt% to an upper limit of 99.9, 99.7, 99.4, 99, 96, 93, 90, or 85 wt% ethylene, based on the total weight of the polymer. The polymer can contain 0.1 to 50 wt% of units derived from comonomers, based on the total weight of the polymer. One or more embodiments provide that ethylene is utilized as the monomer and hexene is utilized as the comonomer.

[0044] As described above, the polymers produced using the compositions disclosed herein can be produced in a fluidized bed reactor. The fluidized bed reactor can have a reaction temperature of 10 to 130 °C. All individual values and subranges from 10 °C to 130 °C are included. For example, the fluidized bed reactor can have a reaction temperature from a lower limit of 10, 20, 30, 40, 50, or 55 °C to an upper limit of 130, 120, 110, 100, 90, 80, 70, or 60 °C.

[0045] The fluidized bed reactor can have an ethylene partial pressure of 30 pounds per square inch (psi) to 250 psi. All individual values and subranges from 30 to 250 psi are included. For example, the fluidized bed reactor can have an ethylene partial pressure from a lower limit of 30, 45, 60, 75, 85, 90, or 95 psi to an upper limit of 250, 240, 220, 200, 150, or 125 psi.

[0046] One or more embodiments provide that ethylene is utilized as the monomer and hexene is utilized as the comonomer. The fluidized bed reactor can have a comonomer to ethylene molar ratio, e.g., C6 / C2, of 0.0001 to 0.100. All individual values and subranges from 0.0001 to 0.100 are included. For example, the fluidized bed reactor can have a comonomer to ethylene molar ratio from a lower limit of 0.0001, 0.0005, 0.0007, 0.001, 0.0015, 0.002, 0.007, or 0.010 to an upper limit of 0.100, 0.080, or 0.050.

[0047] When hydrogen is utilized in the polymerization process, the fluidized bed reactor can have, for example, a hydrogen to ethylene molar ratio (H2 / C2) of 0.00001 to 0.90000. All individual values and subranges from 0.00001 to 0.90000 are included. For example, the fluidized bed reactor can have an H2 / C2 from a lower limit of 0.00001, 0.00005, or 0.00008 to an upper limit of 0.90000, 0.500000, 0.10000, 0.01500, 0.00700, or 0.00500. One or more embodiments provide that hydrogen is not utilized.

[0048] The melting temperature was determined by differential scanning calorimetry according to ASTM D 3418-08.

[0049] Many polymer properties may be determined using conventional compositional gel permeation chromatography. For example, the weight average molecular weight (Mw), number average molecular weight (Mn), Z average molecular weight (Mz), and Mw / Mn (PDI) were determined using a chromatographic system consisting of a PolymerChar GPC-IR (Valencia, Spain) high temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR5). The oven section of the autosampler was set at 160 °C and the column section was set at 150 °C. The columns used were four Agilent “Mixed A” 30 cm, 20 micron linear mixed bed columns. The chromatographic solvent used was 1,2,4-trichlorobenzene, which contained 200 ppm of butylated hydroxytoluene (BHT). The solvent source was nitrogen sparged. The injection volume employed was 200 microliters and the flow rate was 1.0 milliliter / minute.

[0050] Calibration of the GPC column set was performed using 21 narrow molecular weight distribution polystyrene standards having molecular weights in the range of 580 to 8,400,000 g / mol, placed in six “cocktail” mixtures having at least one order of magnitude spacing between individual molecular weights. The standards were purchased from Agilent Technologies. For molecular weights above 1,000,000, the polystyrene standards were prepared at 0.025 grams in 50 milliliters of solvent, and for molecular weights below 1,000,000, at 0.05 grams in 50 milliliters of solvent. The polystyrene standards were pre-dissolved at 80 °C with gentle stirring for 30 minutes, then cooled, and the room temperature solution was transferred to the autosampler dissolution oven at 160 °C and cooled for 30 minutes. The peak molecular weight of the polystyrene standards was converted to polyethylene molecular weight using Equation 1 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)), M ポリエチレン =A×(M ポリスチレン )B (Formula 1) In the formula, M is the molecular weight, A has a value of 0.4061, and B is equal to 1.0.

[0051] A fifth-degree polynomial was used and applied to each polyethylene equivalent calibration point.

[0052] Using decane introduced into a blank sample via a micropump controlled by a PolymerChar GPC-IR system, the total plate number of the GPC column set was performed. The plate number of the chromatography system should exceed 18,000 for four Agilent "Mixed A" 30 cm 20 micron linear mixed-bed columns.

[0053] The sample was prepared in a semi-automatic mode using PolymerChar's "Instrument Control" software, with a target weight of 2 mg / ml for the sample. Solvent (containing 200 ppm of BHT) was added to a vial with a septum cap pre-nitrogen sparged via a PolymerChar high-temperature autosampler. The sample was dissolved at 160 °C for 2 hours under "low-speed" shaking.

[0054] Mn (GPC) , Mw (GPC) , and Mz (GPC) The calculations of were based on the GPC results using PolymerChar's GPCOne (trademark) software, an IR chromatogram with the baseline subtracted at each equally spaced data collection point (i), and the polyethylene equivalent molecular weights obtained from a narrow standard calibration curve for point (i) of Formula 1, according to Formulas 2 - 4, using the internal IR5 detector (measurement channel) of the PolymerChar GPC-IR chromatograph.

[0055]

Number

[0056] To monitor the deviation over time, a flow rate marker (decane) was introduced into each sample via a micropump controlled by a PolymerChar GPC-IR system. Using this flow rate marker (FM), the pump flow rate (apparent flow rate) of each sample was linearly corrected by RV-aligning each decane peak in the sample (RV(FM sample)) with that of the decane peak within the narrow standard calibration (RV(FM calibrated)). Subsequently, any change in the time of the decane marker peak is presumed to be related to a linear shift in the flow rate (effective flow rate) throughout the run. After calibrating the system based on the peak of the flow rate marker, the effective flow rate (relative to the narrow standard calibration) is calculated as per Equation 5. The processing of the flow rate marker peak was performed via PolymerChar's GPCOne™ software. The acceptable flow rate correction should be such that the effective flow rate should be within ±0.5% of the apparent flow rate. Flow rate (effective) = Flow rate (nominal) * (RV(FM calibrated) / RV(FM sample)) (Equation 5)

[0057] IR5 GPC octene composition correction. The calibration of the quantification of the IR5 detector was performed using at least 10 ethylene-based polymer standards (octene as comonomer) produced by single-site metallocene catalysts from a single reactor (polyethylene homopolymers and ethylene / octene copolymers) in solution processes with a narrow SCB distribution in the range of homopolymer (0 SCB / total 1000 carbon atoms) to approximately 40 SCB / total 1000 carbon atoms (where total C = carbon in the main chain + carbon in the branches) and known comonomer content ( 13 measured by C NMR Method, Qiu et al., Anal. Chem. 2009, 81, 8585 - 8589). Each standard had a weight average molecular weight of 36,000 g / mol to 126,000 g / mol measured by GPC. Each standard had a molecular weight distribution (Mw / Mn) of 2.0 to 2.5. The polymer properties of the SCB standards are shown in Table A.

[0058]

Table 1

[0059] "Area response minus the baseline of the IR5 methyl channel sensor" vs. "Area response minus the baseline of the IR5 measurement channel sensor" "IR5 area ratio (or "IR5 メチルチャネル面積 / IR5 測定チャネル面積 ")" (Standard filter and filter wheel supplied by PolymerChar: Part Number IR5_FWM01 is included as part of the GPC-IR instrument) was calculated for each of the "copolymer" standards. A linear fit of weight % comonomer frequency vs. "IR5 area ratio" was constructed in the form of Equation 6 below. Weight % comonomer = A0 + [A1 × (IR5 メチルチャネル面積 / IR5 測定チャネル面積 )] (Equation 6) Where A0 is the "weight % comonomer" at zero "IR5 area ratio", A1 is the slope of "weight % comonomer" vs. "IR5 area ratio", and represents the increase in weight % comonomer as a function of "IR5 area ratio". The IR5 area ratio is equal to the IR5 height ratio for narrow PDI and narrow SCBD standard materials.

[0060] The comonomer distribution or short-chain branch distribution in an ethylene / α-olefin copolymer can be characterized as either normal (also called having a Ziegler-Natta distribution), inverse, or flat. Some of the reported methods are utilized to quantify the broad orthogonal composition distribution (BOCD). Herein, a simple linear fitting is utilized such that the positive or inverse nature of the comonomer distribution can be quantified by the molecular weight comonomer distribution index (MWCDI), which is the slope of the linear regression of the comonomer distribution obtained from the compositional GPC measurement, where the x-axis line is Log(MW) and the y-axis line is the weight percentage of the comonomer. FIG. 1 shows the data plots utilized to determine the MWCDI for Example 3 (MWCDI = 5.91) and the data plots utilized to determine the MWCDI for Comparative Example C (MWCDI = 3.60), as shown in Table 3 of the Examples section of this application. The inverse comonomer distribution is defined when MWCDI > 0, and the normal comonomer distribution is defined when MWCDI < 0. When MWCDI = 0, the comonomer distribution is said to be flat. Additionally, MWCDI quantifies the magnitude of the comonomer distribution. Comparing two polymers with MWCDI > 0, the polymer with the larger MWCDI value is defined to have a larger, i.e., increased BOCD. In other words, the larger the MWCDI value of a polymer, the larger the inverse comonomer distribution. For example, as reported in Table 3, the catalyst of Example 2 has an increased BOCD compared to the catalyst of Comparative Example B. Polymers having a relatively large MWCDI, i.e., BOCD, can provide improved physical properties such as improved film properties compared to polymers having a relatively small MWCDI.

[0061] The polymers produced with the compositions disclosed herein can have an MWCDI of 0.10 to 10.00. All individual values and subranges from 0.10 to 10.00 are included. For example, the polymer can have an MWCDI from a lower limit of 0.10, 0.50, or 1.00 to an upper limit of 10.00, 9.00, 8.00, 8.50, or 8.35.

[0062] The polymers produced with the compositions disclosed herein may have a density of 0.8700 to 0.9700 g / cm 3 . All individual values and subranges of 0.8700 to 0.9700 g / cm 3 are included. For example, the polymer may have a density from a lower limit of 0.8700, 0.9000, 0.9100, 0.9150, 0.9200, or 0.9250 g / cm 3 to an upper limit of 0.9700, 0.9600, 0.9500, 0.9450, 0.9350, or 0.9300 g / cm 3 . The density can be determined in accordance with ASTM D792.

[0063] The polymers produced with the compositions disclosed herein may have a weight average molecular weight (Mw) of 5,000 to 750,000 g / mol. All individual values and subranges of 5,000 to 750,000 g / mol are included. For example, the polymer may have an Mw from a lower limit of 5,000, 10,000, or 15,000 g / mol to an upper limit of 750,000, 500,000, or 200,000 g / mol. As is known in the art, Mw can be determined by gel permeation chromatography (GPC). GPC is discussed herein.

[0064] The polymers produced with the compositions disclosed herein may have a number average molecular weight (Mn) of 3,000 to 300,000 g / mol. All individual values and subranges of 3,000 to 300,000 g / mol are included. For example, the polymer may have an Mn from a lower limit of 3,000, 5,000, or 10,000 g / mol to an upper limit of 300,000, 250,000, or 200,000 g / mol. Mn can be determined by the GPC described below.

[0065] The polymers produced using the compositions disclosed herein may have a Z-average molecular weight (Mz) of 20,000 to 2,000,000 g / mol. All individual values and subranges from 20,000 to 2,000,000 g / mol are included. For example, the polymer may have an Mz from a lower limit of 20,000, 25,000, or 30,000 g / mol to an upper limit of 2,000,000, 1,000,000, 500,000, or 200,000 g / mol. Mz can be determined by GPC.

[0066] The polymers produced using the compositions disclosed herein may have a weight-average molecular weight to number-average molecular weight ratio (Mw / Mn) of 1.00 to 6.00. All individual values and subranges from 1.00 to 6.00 are included. For example, the polymer may have an Mw / Mn from a lower limit of 1.00, 1.50, 2.00, or 2.10 to an upper limit of 6.00, 5.50, or 4.50.

[0067] Some aspects of the present disclosure are provided as follows.

[0068] Aspect 1 is a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand represented by structure (I),

[0069]

Chemical formula

[0070] Aspect 2 provides the symmetric hafnium metallocene of Aspect 1, wherein each X is, independently, a leaving group selected from halogen, (C1-C5) alkyl, CH2SiMe3, and benzyl.

[0071] Aspect 3 provides a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand of Aspect 1 or 2, wherein each X is -Cl represented by Structure (II).

[0072]

Chemical formula

[0073] Aspect 4 provides a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand of any one of Aspects 1 to 2, wherein each X is -CH3 represented by Structure (III).

[0074]

Chemical formula

[0075] Aspect 5 is a method for synthesizing a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand of any one of Aspects 1 to 4, comprising contacting a hafnium complex with an alkali metal complex, wherein the alkali metal complex is represented by the following structure,

[0076]

Chemical formula

[0077] Aspect 6 provides a method of Aspect 5, which involves contacting a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand with 2 molar equivalents of an organomagnesium halide of the formula RMg(halide) or 1 molar equivalent of R2Mg (wherein R is (C1-C5)alkyl, CH2SiMe3, or benzyl, and the halide is Cl or Br) to produce a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand of structure (I), and each X is (C1-C5)alkyl, CH2SiMe3, or benzyl.

[0078] Aspect 7 provides a metallocene catalyst composition comprising a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand of any one of Aspects 1-4, or a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand produced by the method of Aspect 5 or Aspect 6, and an activator (e.g., an alkylaluminoxane such as methylaluminoxane).

[0079] Aspect 8 provides a metallocene catalyst composition of Aspect 7, further comprising a support (e.g., silica such as hydrophobic fumed silica or dehydrated silica).

[0080] Aspect 9 provides a metallocene catalyst composition of Aspect 8, wherein the composition is a spray-dried metallocene catalyst composition.

[0081] Embodiment 10 provides a method of making the metallocene catalyst composition of any one of Embodiments 7-9, comprising contacting a symmetrical hafnium metallocene having an isobutylcyclopentadienyl ligand with an activator but not with a support to obtain a supported metallocene catalyst composition; or contacting a symmetrical hafnium metallocene having an isobutylcyclopentadienyl ligand with an activator and a support to obtain a supported metallocene catalyst composition; or contacting a symmetrical hafnium metallocene having an isobutylcyclopentadienyl ligand with an activator and a support in an inert solvent; or contacting a symmetrical hafnium metallocene having an isobutylcyclopentadienyl ligand with an activator and a support in an inert solvent to obtain a suspension thereof and spray drying the suspension to obtain a spray-dried metallocene catalyst composition; or contacting a symmetrical hafnium metallocene having an isobutylcyclopentadienyl ligand in an inert solvent that can be contacted with a supported or spray-dried activator (or a slurry thereof) to obtain a spray-dried metallocene catalyst composition.

[0082] Example 11 is a method of producing a polyolefin polymer, comprising polymerizing at least one olefin monomer with the metallocene catalyst composition of any one of Examples 7-9, or with any of the metallocene catalyst compositions produced by the method of Example 10, to produce a polyolefin polymer, preferably wherein the at least one olefin monomer is ethylene and, optionally, propene and (C4-C 20 and a comonomer selected from the group consisting of: α-olefins.

[0083] Example 12 provides the method of example 11, wherein the at least one olefin monomer comprises ethylene and a comonomer, and the polyolefin polymer has a Molecular Weight Comonomer Distribution Index (MWCDI) of 0.10 to 10.00, as measured by the MWCDI test method described herein, and preferably the comonomer is selected from the group consisting of 1-butene, 1-hexene, and 1-octene.

[0084] Aspect 13 provides a polyolefin polymer produced by any one of the methods of Aspects 11 to 12.

Example

[0085] 5-(2-Methylpropylidene)cyclopenta-1,3-diene, which can be represented by the following formula,

[0086]

Chemical formula

[0087] was synthesized as follows. In a glove box, pyrrolidine (1.45 g, 10 mol%) was added to a glass container containing a solution of isobutyraldehyde (14.6 g, 203 mmol) and cyclopentadiene (13.4 g, 203 mmol) in MeOH-H2O (200 mL 4 / 1). The contents of the container were transferred to an ice-cooled mixture of aqueous sodium chloride solution and 10 mol% AcOH in a narrow graduated cylinder. The organic phase was isolated and dried over molecular sieves. The product (5-(2-methylpropylidene)cyclopenta-1,3-diene) was filtered to obtain a pale yellow oil, which was then used without further purification (16.0 g, 65%). 1 1H NMR (400 MHz, CDCl3) δ: 6.54 (tdd, J = 5.4, 3.8, 2.5 Hz, 2H), 6.51 - 6.44 (m, 1H), 6.29 - 6.17 (m, 2H), 3.02 (dp, J = 10.0, 6.6 Hz, 1H), 1.15 (d, J = 6.6 Hz, 6H). 13 13C NMR (101 MHz, CDCl3) δ: 149.88, 143.69, 133.08, 130.87, 126.06, 119.36, 30.58, 23.24.

[0088] Isobutylcyclopentadienyllithium, which can be represented by the following formula,

[0089]

Chemical formula

[0090] Et2O (250 mL) was added to a container. 5-(2-Methylpropylidene)cyclopenta-1,3-diene (16.0 g, 133 mmol) was added to the contents of the container with stirring. LiAlH4 (33 mL, 4 M Et2O solution) was added dropwise to the contents of the container with stirring. Bubbling was observed. A white solid precipitated during the addition, and the yellow color gradually disappeared as the addition of LiAlH4 continued. The addition was stopped when the solution became very faintly yellow. The product isobutylcyclopentadienyllithium, which was observed to be a white solid, was collected by filtration, washed with Et2O, and dried under vacuum (13.7 g, 80%).

[0091] Synthesis of Example 1 - Bis(isobutylcyclopentadienyl)hafnium dichloride (Example 1)

[0092]

Chemical formula

[0093] Isobutylcyclopentadienyllithium (0.150 g, 17.7 mmol) and hafnium tetrachloride (0.187 g, 0.585 mmol) were added to a container together with THF and stirred at about 20 °C for about 12 hours. Then, the contents of the container were concentrated to obtain an off-white residue. The residue was extracted with dichloromethane and then filtered. The resulting solution was placed under vacuum to obtain Example 1 (0.276 g, 96%). 1 H NMR (400 MHz, C6D6) δ: 5.83 (t, J = 2.7 Hz, 4H), 5.72 - 5.61 (m, 4H), 2.57 (d, J = 7.0 Hz, 4H), 1.62 (dq, J = 13.5, 6.8 Hz, 2H), 0.80 (d, J = 6.6 Hz, 12H). 13 C NMR (101 MHz, C6D6) δ: 130.67, 116.15, 110.24, 39.50, 30.32, 22.09.

[0094] Example 2, which is a spray-dried composition, was produced as follows. In a nitrogen-purged glove box, hydrophobic fumed silica (CABOSIL TS-610, 1.33 grams) and toluene (37.5 grams) were added to a container and mixed, and then a 10 wt% solution of methylaluminoxane (MAO) in toluene (11 grams) was added. The contents of the container were stirred for about 15 hours. Then, Example 1 (0.049 grams) was added to the container, and the contents of the container were stirred for about 30 minutes. Then, the contents of the container were spray-dried using a Buchi Mini Spray Drier B-290 (set temperature 140 °C, reaction temperature 100 °C, aspirator 95, pump speed 150 rpm) to obtain Example 2 (Example 2).

[0095] Hafnium metallocene (bis-(n-propylcyclopentadienyl)hafnium dichloride) having two two n-propylcyclopentadienyl ligands, which is Comparative Example A (Example A), was commercially obtained from TCI.

[0096] [Chemical formula]

[0097] Comparative Example B (Comparative Example B), which is a spray-dried composition, was produced as follows. In a nitrogen-purged glove box, hydrophobic fumed silica (CABOSIL TS-610, 2.65 grams) and toluene (75 grams) were added to a container and mixed, and then a 10 wt% solution of methylaluminoxane (MAO) in toluene (22 grams) was added. The contents of the container were stirred for about 15 hours. Then, Comparative Example A (0.105 grams) was added to the container, and the contents of the container were stirred for about 30 minutes. Then, the contents of the container were spray-dried using a Buchi Mini Spray Drier B-290 (set temperature 140 °C, reaction temperature 100 °C, aspirator 95, pump speed 150 rpm) to obtain Comparative Example B (Comparative Example B).

[0098] Comparative Example C (Comparative Example C), which is a hafnium metallocene having two two n-butylcyclopentadienyl ligands (bis(n-butylcyclopentadienyl)hafnium dichloride), was produced as follows.

[0099]

Chemical formula

[0100] In a glove box, hafnium tetrachloride (2.068 g) and dimethyl ether (DME, 30 g) were charged into a 4-ounce container (first jar) to obtain a white mixture. A solution of n-butylcyclopentadienyllithium (1.68 g) in DME (30 g) was slowly added to the stirred contents of the first jar to obtain an opaque orange mixture. The resulting mixture was stirred at room temperature (20 °C) overnight (18 hours), and then the solvent was removed in vacuo. The resulting residue was dissolved in toluene and placed in a freezer (-30 °C). Pale orange crystals (0.500 g) of Comparative Example C were obtained. Property evaluation: 1 H NMR (400 MHz, benzene-d6) δ 5.83 (t, J = 2.7 Hz, 4H), 5.67 (t, J = 2.7 Hz, 4H), 2.77 - 2.62 (m, 4H), 1.50 - 1.36 (m, 4H), 1.22 (h, J = 7.3 Hz, 4H), 0.84 (t, J = 7.3 Hz, 6H).

[0101] Comparative Example D (Comparative Example D), which is a spray-dried composition, was produced as follows. In a nitrogen-purged glove box, hydrophobic fumed silica (CABOSIL TS-610, 2.65 grams) and toluene (70 grams) were added to a container and mixed, and then a 10 wt% solution of methylaluminoxane (MAO) in toluene (22 grams) was added. The contents of the container were then stirred for about 15 hours. Then, Comparative Example C (0.115 grams) was added to the container, and the contents of the container were stirred for about 30 minutes. Then, the contents of the container were spray-dried using a Buchi Mini Spray Drier B-290 (set temperature 140 °C, reaction temperature 100 °C, aspirator 95, pump speed 150 rpm) to obtain Comparative Example D (Comparative Example D).

[0102] The polymerization was carried out as follows. For each polymerization, a laboratory-scale gas-phase polymerization reactor (a 2-liter stainless-steel autoclave equipped with a variable-speed mechanical stirrer) was dried at 100 °C for 1 hour, then dry NaCl (200 g) was charged, and it was heated to 100 °C for 30 minutes under a nitrogen stream. Then, the reactor was purged with nitrogen, 3 g of silica-supported methylaluminoxane was added to the reactor as a scavenger, the reactor temperature was adjusted to approximately the desired temperature, the reactor was sealed, and the contents of the reactor were stirred. The reactor was pre-filled with hydrogen, ethylene, and 1-hexene to the desired pressure. Once the steady state was reached, the catalyst was introduced into the reactor at a temperature of 80 °C to initiate the polymerization. The reactor temperature was maintained at the desired temperature for a 60-minute polymerization. The hydrogen, C6 / C2 ratio, and ethylene pressure were kept constant. At the end of the 60-minute polymerization, the reactor was cooled, vented, and opened. The resulting mixture was washed with water and methanol and dried. The polymerization conditions for Examples 3-9 and Comparative Examples C-O are reported in Table 1.

[0103] Several properties of the polymers produced in Examples 3-9 and Comparative Examples C-O, respectively, were determined. The results are reported in Tables 2 and 3. The catalyst productivity (polymer (grams) / catalyst (grams)-hour) was determined as the ratio of the produced polymer to the amount of catalyst added to the reactor. The melt index (I2) was determined according to ASTM D1238 (190 °C, 2.16 kg), the melt index (I5) was determined according to ASTM D1238 (190 °C, 5 kg), and the melt index (I 21 ) was determined according to ASTM D1238 (190 °C, 21.6 kg). The molecular weight comonomer distribution index (MWCDI) was determined as discussed herein. The melting temperature was determined using differential scanning calorimetry according to ASTM D 3418-08, using a scan rate of 10 °C / min for a 10 mg sample and using the second heating cycle to determine T m was determined. M w , M n , M z , M w / M n (PDI), and Mz / M w was determined as described above in the detailed description. The comonomer content incorporated in the polymer, for example, 1 - hexene, was determined by high - speed FT - IR spectroscopy for the dissolved polymer in GPC measurement as described above in the detailed description.

[0104]

Table 2

[0105]

Table 3

[0106]

Table 4

[0107] The data in Tables 2 - 3 show that the polymer produced using Example 2 had a more quantifiable inverse SCBD or BOCD (MWCDI), which is a desirable feature. In addition, the polymer produced using Example 2 also had a higher comonomer incorporation (wt% C6), which is also a desirable feature. In addition, with the exception of high C6 / C2 (e.g., 0.016) and low H2 / C2 (e.g., 0.0005), Example 2 had the following advantages over the catalyst of Comparative Example B, and the increase in H2 / C2 seems to improve the productivity of Example 2 while impairing the productivity of Comparative Example B. This suggests that Example 2 is a more robust catalyst and can withstand a wider range of process conditions. In addition, Example 2 had an improved, i.e., larger molecular weight comonomer distribution index compared to the polymers produced using Comparative Example A or B. In other words, Example 2 was better at incorporating comonomers (e.g., a higher wt% of 1 - hexene under the same conditions).

[0108] As shown in Table 3, FIG. 1 shows data plots utilized to determine the MWCDI for Example 3 (MWCDI = 5.91) and Comparative Example C (MWCDI = 3.6). Data plot 102 corresponds to the determination of the MWCDI for Example 3. Data plot 104 corresponds to the determination of the MWCDI for Comparative Example C. The polymerization conditions of Example 5, Comparative Example E, and Comparative Example L are representative examples of higher density polymers, showing that Example 5 maintains a good BOCD and a higher MWCDI than Comparative Example E or Comparative Example L. Example 7 and Comparative Example G were produced at a high temperature (90 °C) that has an adverse effect on the BOCD. However, Example 7 maintained a significantly higher and still good MWCDI value than Comparative Example G. Example 8, Comparative Example H, and Comparative Example N were both polymerized at both a high temperature (100 °C) and a low C6 / C2 (high density) that have an adverse effect on the BOCD (MWCDI) of Comparative Example H and Comparative Example N. Example 8 still maintained a fairly high MWCDI under these more stringent conditions. Finally, Example 9, Comparative Example I, and Comparative Example O were produced at a polymerization temperature of 90 °C and a high C6 / C2 (low density) such that the polymer has a melt index of less than 1, but at a higher H2 / C2. Example 9 continued to have a larger MWCDI than Comparative Example I produced by Comparative Example B.

Claims

1. A symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand represented by structure (I), 【Chemistry 1】 Each X independently has an isobutylcyclopentadienyl ligand, forming a symmetric hafnium metallocene.

2. Each X independently produces a halogen, (C １ ~C ５ ) alkyl, CH ２ SiMe ３ A symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand according to claim 1, wherein the leaving group is selected from benzyl.

3. A symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand according to claim 1, wherein each X is -Cl represented by structure (II). 【Chemistry 2】

4. Each X is represented by structure (III) - CH ３ The symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand as described in claim 1. 【Transformation 3】

5. A method for synthesizing a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand as described in Claim 1, The process involves contacting a hafnium complex with an alkali metal complex, wherein the alkali metal complex is represented by the following structure: 【Chemistry 4】 In the formula, M' is lithium, sodium, or potassium, and R １ However, it is an isobutyl group, A method for synthesizing a symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand, wherein the hafnium complex is hafnium tetrachloride.

6. The symmetric hafnium metallocene having the isobutylcyclopentadienyl ligand is contacted with 2 molar equivalents of an organomagnesium halide of the formula RMg (halide) or 1 molar equivalent of R ２ Mg (where R is (C １ -C ５ ) alkyl, CH ２ SiMe ３ , or benzyl, and the halide is Cl or Br), to produce the symmetric hafnium metallocene having the isobutylcyclopentadienyl ligand of structure (I), and each X is (C １ -C ５ ) alkyl, CH ２ SiMe ３ , or benzyl, the method according to claim 5.

7. A metallocene catalyst composition, Symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand as described in any one of claims 1 to 4, or symmetric hafnium metallocene having an isobutylcyclopentadienyl ligand produced by the method described in claim 5 or claim 6, and A metallocene catalyst composition containing an activator.

8. The metallocene catalyst composition according to claim 7, further comprising a carrier.

9. The metallocene catalyst composition according to claim 8, wherein the composition is a spray-dried metallocene catalyst composition.

10. A method for producing the metallocene catalyst composition according to Claim 7, comprising: contacting the symmetric hafnium metallocene having the isobutylcyclopentadienyl ligand with the activator instead of the support to obtain the metallocene catalyst composition without a support; or contacting the symmetric hafnium metallocene having the isobutylcyclopentadienyl ligand with the activator and the support to obtain the metallocene catalyst composition with a support; or contacting the symmetric hafnium metallocene having the isobutylcyclopentadienyl ligand with the activator and the support in an inert solvent. A method for producing a metallocene catalyst composition, comprising: contacting the isobutylcyclopentadienyl ligand with a support; contacting the symmetric hafnium metallocene having the isobutylcyclopentadienyl ligand with the activator and the support in an inert solvent to obtain a suspension thereof; spray-drying the suspension to obtain the spray-dried metallocene catalyst composition; or contacting the symmetric metallocene having the isobutylcyclopentadienyl ligand with a supported or spray-dried activator (or its slurry) in an inert solvent to obtain the spray-dried metallocene catalyst composition.

11. A method for producing polyolefin polymers, The process includes polymerizing at least one olefin monomer with the metallocene catalyst composition described in claim 7 to produce the polyolefin polymer, preferably the at least one olefin monomer being ethylene and optionally propene and (C ４ ~C ２０ A method for producing a polyolefin polymer comprising a comonomer selected from the group consisting of α-olefins.

12. The method according to claim 11, wherein the at least one olefin monomer comprises ethylene and the comonomer, and the polyolefin polymer has a molecular weight comonomer distribution index (MWCDI) of 0.10 to 10.00 as measured by the MWCDI test method described herein, and preferably the comonomer is selected from the group consisting of 1-butene, 1-hexene, and 1-octene.

13. A polyolefin polymer produced by the method described in Claim 11.

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