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WO1995013872A1 - Catalyst for preparing alpha-olefin polymers and copolymers - Google Patents

Catalyst for preparing alpha-olefin polymers and copolymers Download PDF

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Publication number
WO1995013872A1
WO1995013872A1 PCT/US1994/013434 US9413434W WO9513872A1 WO 1995013872 A1 WO1995013872 A1 WO 1995013872A1 US 9413434 W US9413434 W US 9413434W WO 9513872 A1 WO9513872 A1 WO 9513872A1
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WIPO (PCT)
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bis
cyclopentadienyl
metallocene
dichloride
trimethylaluminum
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PCT/US1994/013434
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French (fr)
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Yuri Viktorovich Kissin
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Mobil Oil Corporation
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Publication of WO1995013872A1 publication Critical patent/WO1995013872A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/12—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides
    • B01J31/14—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides of aluminium or boron
    • B01J31/143—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides of aluminium or boron of aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
    • B01J31/22—Organic complexes
    • B01J31/2282—Unsaturated compounds used as ligands
    • B01J31/2295—Cyclic compounds, e.g. cyclopentadienyls
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/40—Complexes comprising metals of Group IV (IVA or IVB) as the central metal
    • B01J2531/46—Titanium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/40—Complexes comprising metals of Group IV (IVA or IVB) as the central metal
    • B01J2531/48—Zirconium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/40—Complexes comprising metals of Group IV (IVA or IVB) as the central metal
    • B01J2531/49—Hafnium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
    • B01J31/1616—Coordination complexes, e.g. organometallic complexes, immobilised on an inorganic support, e.g. ship-in-a-bottle type catalysts
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00—Polymerisation catalysts
    • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62—Refractory metals or compounds thereof
    • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
    • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
    • C08F4/65912—Component covered by group C08F4/64 containing a transition metal-carbon bond in combination with an organoaluminium compound
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00—Polymerisation catalysts
    • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62—Refractory metals or compounds thereof
    • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
    • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
    • C08F4/65916—Component covered by group C08F4/64 containing a transition metal-carbon bond supported on a carrier, e.g. silica, MgCl2, polymer
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00—Polymerisation catalysts
    • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62—Refractory metals or compounds thereof
    • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
    • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
    • C08F4/6592—Component covered by group C08F4/64 containing a transition metal-carbon bond containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring
    • C08F4/65922—Component covered by group C08F4/64 containing a transition metal-carbon bond containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring containing at least two cyclopentadienyl rings, fused or not

Definitions

  • This invention relates to a catalyst for preparing alpha- olefin polymers and copolymers; the invention also relates to a process for preparing such polymers and copolymers.
  • the invention is particularly concerned with a catalyst for preparing ethylene polymers and copolymers.
  • Metallocene compounds of transition metals are used as catalyst precursors for polymerization and copolymerization of ethylene and in the stereospecific polymerization of olefins. Metallocenes can be described by the empirical formula Cp m MA n B p . These compounds in combination with an aluminoxane such as methylaluminoxane (MAO) have been used to produce olefin polymers and copolymers, such as ethylene and propylene homopolymers, ethylene-butene and ethylene-hexene copolymers, e.g., see US-A-4542199 and US-A-4404344.
  • MAO methylaluminoxane
  • MAO has been used as a co-catalyst with various metallocenes. It comprises mixtures of oligomeric linear and/or cyclic aluminoxanes with an average molecular weight of about 1200 represented by the formulas: R-(Al(R)-0) n -AlR 2 for linear aluminoxanes; and (-Al(R)-0-) m for cyclic alumoxanes wherein n is 1-40, m is 3-40, and R is preferably methyl.
  • MAO has presented problems in the development of catalysts formed from metallocenes. Because of the varying chemical makeup of the material itself, as reflected by its formula above, it can be difficult to obtain reproducible catalyst synthesis results. If supported catalysts are prepared with combinations of metallocenes and MAO, MAO is not always uniformly distributed within catalyst particles. The resulting non-homogeneous polymerization catalysts have low activity and produce resins with less attractive properties.
  • the present invention seeks to provide a solution to this problem.
  • a catalyst composition for producing alpha-olefin polymers or copolymers comprising:
  • a metallocene wherein the metallocene has the formula: Cp m MA n B p , wherein Cp is a cyclopentadienyl or a substituted cyclopentadienyl group; m is 1 or 2; M is titanium, zirconium or hafnium; and each of A and B is selected from the group consisting of a halogen atom, a hydrogen atom and an alkyl group, providing that m+n+p is equal to the valency of the metal M;
  • trimethylaluminum wherein the Al(0H) x 0 y is used in an amount sufficient to provide and an Al(OH) x 0 y :metallocene molar ratio of 5 to 10,000; the trimethylaluminum is used in an amount sufficient to provide a trimethylaluminum:metallocene molar ratio of 50 to 10,000; and the Al(0H) x 0 y and the trimethylaluminum are used in amounts to provide a molar ratio of trimethylaluminum to Al(0H) x 0 y in the range of from 0.1 to 100.
  • the Al(0H) x 0 y is A1(0H) 3 or A1(0)0H.
  • the metallocene is biscyclopentadienylzirconium dichloride; or biscyclopentadienyltitanium dichloride.
  • the catalyst may be supported or unsupported, but in a most preferred embodiment, the catalyst is a supported catalyst in which the metallocene is supported on a carrier, which is porous and has a particle size of 1 to 500 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of 0.5 to 5.0 cm 3 /g.
  • a process for preparing a catalyst for producing alpha-olefin polymers or copolymers comprising the steps of: (i) preparing a catalyst precursor by providing silica which is porous and has a particle size of 1 to 200 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of
  • Cp is a cyclopentadienyl or a substituted cyclopentadienyl group, m is 1 or 2
  • M is titanium, zirconium or hafnium, and each of A and B is selected from the group consisting of a halogen atom, a hydrogen atom and an alkyl group, providing that m+n+p is equal to the valency of the metal M; and ii) combining the impregnated catalyst precursor (i) with a combination of: an inorganic aluminum compound
  • Al(OH) x O y in the range of from 0.1 to 100.
  • the mixture of trimethylaluminum and Al(OH) x .O y is subjected to ultrasonic irradiation prior to combining it with the catalyst precursor.
  • the transition metal atom M in the metallocene compound is zirconium.
  • the Cp group is an unsubstituted, a mono- or a polysubstituted cyclopentadienyl group.
  • the substituents on the cyclopentadienyl group may be straight-chain Cj-C 6 alkyl groups.
  • the cyclopentadienyl group can be also a part of a bicyclic or a tricyclic moiety such as indenyl, tetrahydroindenyl, fluorenyl or a partially hydrogenated fluorenyl group, as well as a part of a substituted bicyclic or tricyclic moiety.
  • m in the above formula of the metallocene compound is equal to
  • the cyclopentadienyl groups can be also bridged by alkyl groups, such as -CH 2 -, -CH 2 -CH 2 -, -CR'R"- and -CR'R"-CR'R”-, where R' and R" are short alkyl groups or hydrogen atoms; or dialkylsilane groups, such as -Si(CH 3 ) 2 -, Si(CH 3 ) 2 -CH 2 -CH 2 -
  • Bridged cyclopentadienyl complexes are used for stereospecific polymerization of propylene. If the A and B substituents in the above formula of the metallocene compound are halogen atoms, they belong to the group of fluorine, chlorine, bromine or iodine.
  • substituents A and B in the above formula of the metallocene compound are alkyl groups, they are preferably straight-chain or branched C j -Cg alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl or n-octyl.
  • Suitable metallocene compounds include: bis (cyclopentadienyl)metal dihalides; bis (cyclopentadienyl) metal hydridohalides ; bis (cyclopentadienyl) metal monoalkyl monohalides; bis (cyclopentadienyl)metal dialkyls;and bis (indenyl) metal dihalides, wherein the metal is titanium, zirconium or hafnium, and the halide atoms are preferably chlorine, and the alkyl groups are preferably C j -C, ⁇
  • metallocenes include: bis (cyclopentadienyl) zirconium dichloride; bis (cyclopentadienyl) hafnium dichloride; bis (cyclopentadienyl ) titanium dichloride; bis (cyclopentadienyl) zirconium dimethyl ; bis (cyclopentadienyl) hafnium dimethyl;
  • the support carrier material is a particulate, porous, solid such as an oxide of silicon and/or of aluminum, or a crosslinked polymer, e.g. polystyrene.
  • the carrier material can be used in the form of a dry powder and has an average particle size of from 1 to 500 microns, preferably from 1 to 250 microns, more preferably from 10 to 150 microns.
  • the surface area of the carrier is preferably at least 50 m 2 /g up to 350 m 2 /g.
  • the carrier material should preferably be dry, i.e., free of absorbed water.
  • Drying of the inorganic carrier material can be effected by heating at about 100°C to about 1000°C, preferably at about 600°C.
  • the carrier is silica, it is preferably heated to at least 200°C, preferably about 200°C to about 850°C and most preferably at about 600°C.
  • the carrier is silica which, prior to the use thereof in the catalyst synthesis, has been dehydrated by fluidizing it with nitrogen and heating at about 600°C for about 4 to 16 hours.
  • the silica of the most preferred embodiment is a high surface area, amorphous silica with a surface area of 300 m 2 /g and a pore volume of 1.65 cm 3 /g.
  • Supporting of a metallocene compound on a carrier is undertaken by dissolving the metallocene in a solvent under anhydrous conditions, slurrying the carrier in the solvent containing the metallocene in order to impregnate the carrier with the metallocene, and removing the solvent to recover a dry particulate supported metallocene.
  • Slurrying and contact of metallocene solution with a support can be undertaken at temperatures ranging from 20 to 60°C, preferably 30 to 55°C.
  • Solvent removal, after the impregnation may be undertaken at a temperature up to 60°C, with or without a nitrogen purge.
  • the solvent in this step may be an aromatic, aliphatic or
  • the solvent in this step may be an aromatic, aliphatic or chlorinated hydrocarbon, an ether, a cyclic ether, an ester, or a ketone.
  • the loading of the metallocene on the support is in the range of 0.1 to 1.0 grams per gram of support, preferably 0.25 to 0.45 grams per gram of support.
  • the unsupported or supported metallocene, in slurry or in solution is then contacted with Al(OH) x O y and TMA.
  • the amount of TMA in the cocatalyst composition is sufficient to give an Al:metallocene molar ratio of about 50 to about 10,000, preferably about 100 to about 1,000.
  • TMA and the inorganic aluminum compound Al(OH) x O y can be used to contact the metallocene compound separately or as a mixture. Contact with the metallocene can be undertaken in the polymerization reactor by feeding either one or the other of TMA and Al(OH) x O y seriatim to the reactor or feeding a mixture comprising TMA and Al(OH) x O y to the polymerization reactor.
  • activation of the metallocene can be undertaken prior to introduction of the activated catalyst into the polymerization reactor by contacting either one or the other of TMA and Al(OH) x O y seriatim with the metallocene or contacting the metallocene with a mixture comprising TMA and Al(OH) x O y for up to about 2 hours prior to the introduction thereof into the polymerization medium at a temperature of from about -40 to about 100°C.
  • Activity of the cocatalysts can be increased by reacting TMA and the inorganic aluminum compound at elevated temperatures or by subjecting the binary mixture of TMA and the inorganic aluminum compound to ultrasonic irradiation.
  • the catalyst synthesis of the present invention is undertaken in the substantial absence of water, oxygen, and other catalyst poisons.
  • catalyst poisons can be excluded during the catalyst preparation steps by any well known methods, nitrogen, argon or other inert gas.
  • Alpha-olefins can be polymerized with the catalysts prepared according to the present invention by any suitable process. Such processes include polymerizations carried out in suspension, in solution or in the gas phase.
  • the molecular weights of the polymers may be controlled in a known manner, e.g., by using hydrogen when the polymerization is carried out at temperatures from about 30 to about 105°C. Pressures used in polymerization reactions are preferably above ambient and below 1000 psi (6.9 MPa) , more preferably below 400 psi (2.8 MPa) and most preferably from 100 to 350 psi (690 KPa to 2.4 MPa).
  • aromatic solvents e.g., toluene
  • aliphatic solvents e.g. heptane
  • Linear ethylene polymers can be prepared using the catalyst according to the invention. These polymers may be homopolymers of ethylene or copolymers of ethylene with one or more C 3 -C 10 alpha-olefins. Thus, copolymers having two monomeric units are possible as well as terpolymers having three monomeric units.
  • polymers include ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1-octene copolymers, ethylene/4-methyl-l-pentene copolymers, ethylene/1- butene/1-hexene terpolymers, ethylene/propylene/1-hexene terpolymers and ethylene/propylene/1-butene terpolymers.
  • the most preferred comonomers are 1-butene and 1-hexene.
  • the linear low density polyethylene polymers produced in accordance with the present invention preferably contain at least about 80 percent by weight of ethylene units. It is also possible to polymerize propylene with the metallocene catalysts of the invention to produce stereoregular products.
  • a stainless-steel autoclave (volume 500 cm 3 ) equipped with a stirrer, a thermocouple and several ports for adding reaction components was purged with dry nitrogen and filled with 200 cm 3 of dry n-heptane and 50 cm 3 of 1-hexene, after which 5 cm 3 of 20 wt.% solution of A1(CH3) 3 in heptane and 0.2 g of Al(OH) 3 were added to the reactor. Temperature was raised to 70°C and 0.5 cm 3 c of a solution of (C 5 H 5 ) 2 ZrCl 2 in toluene containing 1.710 "3 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 60 min to yield 26.0 g of ethylene/1- hexene copolymer with a hexene content of 1.9 mol.% and an I 2 value of 1.1.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 30 min to yield 24.2 g of ethylene/1-hexene copolymer with a hexene content of 2.3 mol.% and a I 2 value of 9.2.
  • Measurements of the ethylene consumption rates with a gas flow-meter during this polymerization experiment showed that the polymerization rate was 60% higher than in Example 1 in which no ultrasonic irradiation was applied to the cocatalyst system.
  • An autoclave (the same as in Example 1) was purged with dry nitrogen and filled with 200 cm 3 of dry n-heptane and 50 cm 3 of 1-hexene, after which 2 cm 3 of 20 wt% solution of A1(CH 3 ) 3 in heptane and 0.1 g of Al(OH) 3 were added to the reactor. Temperature was raised to 70°C and 0.25 cm 3 of a solution of (n-C 4 H 9 -C 5 H 4 ) 2 ZrCl 2 in toluene containing 6.210 4 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 24.1 g of ethylene/hexene copolymer with a hexene content of 2.6 mol% and an I 2 value of 3.2.
  • the cocatalyst was prepared as follows. To an autoclave (the same as in Example 1) were added 0.10 g of Al(OH) 3 , 10 cm 3 of dry toluene and 2 cm 3 of 15.5 wt.% solution of A1(CH 3 ) 3 in toluene. Reactor temperature was increased to 150°C, the mixture reacted at this temperature for 2 hours and then was cooled to 25°C. The polymerization was carried out as follows.
  • An autoclave (the same as in Example 1) was filled with 200 cm 3 of dry n-heptane and 50 cm 3 of 1-hexene, after which 2 cm 3 of 20 wt.% solution of A1(CH 3 ) 3 in heptane and 0.1 g of A1(0H) 3 were added to the reactor. Temperature was raised to 70°C and 0.5 cm 3 of a solution of (CH 3 -C 5 H 4 ) 2 ZrCl 2 in toluene containing 1.610 3 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 Mpa) and a polymerization reaction was continued for 120 min to yield 18.9 g of ethylene/1-hexane copolymer with a hexene content of 2.1 mol% and an I 2 value of 14.9.
  • An autoclave (the same as in Example 1) was filled with 200 cm 3 of dry n-heptane and 50 cm 3 of 1-hexene, after which 2 cm 3 of 20 wt% solution of A1(CH 3 ) 3 in heptane and 0.2 g of A1(0H) 3 were added to the reactor. Temperature was raised to 70°C and 4.0 cm 3 of a solution of ethylene-bis(idenyl)ZrCl 2 in toluene containing 4.910 4 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 90 min to yield 6.8 g of ethylene/1-hexene copolymer with a hexene content of 5.8 mol% and an I 2 value of 21.
  • a zirconocene-based supported catalyst was prepared by reacting 1.0 g of silica dehydrated at 600°C and a solution of 0.080 g of (C 5 H 5 ) 2 ZrCl 2 in 10 cm 3 of dry tetrahydrofuran for 10 min after which the solvent was stripped from the solid catalyst slurry by nitrogen purge at 70°C for 2 h.
  • An autoclave (the same as in Example 1) was filled with 200 cm 3 of dry n-heptane and 50 cm 3 of 1-hexene after which 2 cm 3 of 20 wt.% solution of A1(CH 3 ) 3 in heptane and 0.2 g of A1(0H) 3 were added to the reactor.
  • An autoclave (the same as in Example 1) was filled with 200 cm 3 of dry n-heptane and 50 cm 3 of 1-hexene, after which 4 cm 3 of 20 wt% solution of A1(CH 3 ) 3 in heptane and 0.35 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 1.0 cm 3 of a solution of (C 5 H 5 ) 2 ZrCl 2 in toluene containing 3.410 3 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 Mpa) and a polymerization reaction was continued for 210 min to yield 26.4 g of ethylene/1-hexene copolymer with a hexene content of 3.0 mol% and an I 2 value of 4.3.
  • An autoclave (the same as in Example 1) was filled with 100 cm 3 of dry toluene and 25 cm 3 of 1-hexene, after which 4 cm 3 of 20 wt% solution of A1(CH 3 ) 3 in heptane and 0.35 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 0.5 cm 3 of a solution of (n-C 4 H 9 -C 5 H 4 ) 2 ZrCl 2 in toluene containing 1.210 3 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 14.4 g of ethylene/1-hexene copolymer with a hexene content of 0.9 mol% and an I 2 value of 1.8.
  • An autoclave (the same as in Example 1) was filled with 200 cm 3 of dry toluene and 50 cm 3 of 1-hexene, after which 4 cm 3 of 20 wt% solution of A1(CH3) 3 in heptane and 0.50 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 1.0 cm 3 of a solution of (C 5 H 5 ) 2 Zr(CH 3 ) 2 in toluene containing 3.310 3 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 Mpa) and a polymerization reaction was continued for 120 min to yield 28.5 g of ethylene/1-hexene copolymer with a hexene content of 2.6 mol% and an I 2 value of 2.5.
  • An autoclave (the same as in Example 1) was filled with 200 cm 3 of dry toluene and 50 cm 3 of 1-hexene, after which 4 cm 3 of 20 wt% solution of A1(CH 3 ) 3 in heptane and 0.50 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 1.0 cm 3 of a solution of (C 5 H 5 ) 2 TiCl 2 in toluene containing 4.010 3 mmol Zr was introduced.
  • Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 17.0 g of ethylene/1-hexene copolymer with a hexene content of 4.0 mol% hexene.
  • the cocatalyst was prepared as follows. A 15cm 3 three- necked glass flask was equipped with an ultrasonic tool described in Example 2 and 0.29 g of A1(0)0H was placed in it. Then 10 cm 3 of dry toluene and 5 cm 3 of 20 wt.% solution of A1(CH 3 ) 3 in heptane was added to the flask and the slurry was irradiated with ultrasound (ca. 30 watt power) for 5 min.
  • the polymerization was carried out as follows. An autoclave (the same as in Example 1) was filled with 200 cc of dry toluene and 50 cm 3 of 1-hexene, after which all contents of the flask used for preparation of the cocatalyst system, about 15 cm 3 , was transferred into the reactor. The temperature was raised to 70°C and 0.5 cm 3 of a solution of (C 5 H s ) ZrCl 2 in toluene containing 1.710 3 mmol Zr was introduced.
  • the cocatalyst was prepared as follows. To an autoclave (the same as in Example 1) were added 0.10 g of A1(0)0H, 10 cm 3 of dry toluene and 2 cm 3 of 15.5 wt.% solution of A1(CH 3 ) 3 in toluene. Reactor temperature was increased to 150°C, the mixture reacted at this temperature for 2 hours and then was cooled to 25°C. The polymerization was carried out as follows.
  • the cocatalyst was prepared as follows. To an autoclave (the same as in Example 1) were added 0.10 g of A1 2 0 3 , 10 cm 3 of dry toluene and 2 cm 3 of 15.5 wt.% solution of A1(CH 3 ) 3 in toluene. Reactor temperature was increased to 150°C, the mixture reacted at this temperature for 2 hours and then was cooled to 25°C.
  • the polymerization was carried out as follows. 250 cm 3 of dry hexane and 50 cm 3 of dry 1-hexene were added to the reactor, its temperature was raised to 70°C and 1 cc of a solution of (n- C 4 H 9 -C 5 H 4 ) 2 ZrCl 2 i- n toluene containing 2.510 4 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and the polymerization was continued for 120 min to yield 3.5 g of ethylene/hexene copolymer with a hexene content of 2.0 mol.% and an I 2 value of 0.13.
  • the gas phase polymerization was carried out as follows. An autoclave (the same as in Example 1) was filled with 30 g of degassed crystalline polypropylene which served as a polymerization medium. 6 cm 3 of 1-hexane, 0.33 g of A1(0H) 3 and 3 cm 3 of 20 wt.% solution of A1(CH 3 ) 3 in heptane was added to the reactor and temperature was raised to 70°C. After that, 0.071 g of the supported catalyst described in Example 8 was introduced into the reactor. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 26.3 g of ethylene/1-hexene copolymer.
  • methylaluminoxane is soluble in aromatic solvents such as toluene whereas the cocatalyst systems of this invention are not soluble in these solvents.
  • the cocatalyst was prepared as follows. In a 40 cm 3 centrifuge flask capped with a septum, 0.10 g of A1(0H) 3 was slurried in 5 cm 3 of dry toluene, and 1 cm 3 of 15.5 wt.% solution of A1(CH 3 ) 3 in toluene was added to it resulting in evolution of gaseous products. The slurry was reacted at 50°C for 4 hours. After that the slurry was centrifuged and the whole liquid fraction of it was withdrawn from the flask with a syringe and was used as Cocatalyst A. The solid remaining in the flask was reslurried in 5 cm 3 of dry toluene and was used as cocatalyst B.
  • the polymerization was carried out as follows. In two separate experiments, an autoclave (the same as in Example 1) was filled with 200 cm 3 of dry n-heptane and 50 cm 3 of 1-hexene, after which 1 cm 3 of A1(CH 3 ) 3 solution in heptane was added to it to purify the reaction medium. Polymerization Experiment A. Clear liquid produced in the cocatalyst preparation step was added to the reactor, temperature was raised to 70°C and 0.5 cm 3 of a solution of (C 5 H 5 ) 2 ZrCl 2 in toluene containing 1.710 3 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 60 min. Less than 2 g of a solid product was recovered.

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Abstract

The invention relates to unsupported or supported catalyst compositions for alpha-olefin (ethylene and/or propylene) polymerization which comprises (1) a metallocene compound, (2) an inorganic aluminum compound A1(OH)xOy, wherein x is a number from 0 to 3, wherein x + 2y = 3, (3) trimethylaluminum, wherein A1(OH)xOy is used in an amount sufficient to provide an A1(OH)xOy:metallocen molar ration of 5 to 10,000, wherein trimethylaluminum is used in an amount sufficient to provide a trimethylaluminum:metallocene molar ratio of 50 to 10,000, and wherein the two aluminum compounds, (2) and (3), are used in amounts to provide a molar ratio of trimethylaluminum to A1(OH)xOy in the range of from 0.1 to 100.

Description

Catalyst for Preparing Alpha-Olefin Polymers and Copolymers
This invention relates to a catalyst for preparing alpha- olefin polymers and copolymers; the invention also relates to a process for preparing such polymers and copolymers. The invention is particularly concerned with a catalyst for preparing ethylene polymers and copolymers.
Metallocene compounds of transition metals are used as catalyst precursors for polymerization and copolymerization of ethylene and in the stereospecific polymerization of olefins. Metallocenes can be described by the empirical formula CpmMAnBp. These compounds in combination with an aluminoxane such as methylaluminoxane (MAO) have been used to produce olefin polymers and copolymers, such as ethylene and propylene homopolymers, ethylene-butene and ethylene-hexene copolymers, e.g., see US-A-4542199 and US-A-4404344.
MAO has been used as a co-catalyst with various metallocenes. It comprises mixtures of oligomeric linear and/or cyclic aluminoxanes with an average molecular weight of about 1200 represented by the formulas: R-(Al(R)-0)n-AlR2 for linear aluminoxanes; and (-Al(R)-0-)m for cyclic alumoxanes wherein n is 1-40, m is 3-40, and R is preferably methyl.
The use of MAO has presented problems in the development of catalysts formed from metallocenes. Because of the varying chemical makeup of the material itself, as reflected by its formula above, it can be difficult to obtain reproducible catalyst synthesis results. If supported catalysts are prepared with combinations of metallocenes and MAO, MAO is not always uniformly distributed within catalyst particles. The resulting non-homogeneous polymerization catalysts have low activity and produce resins with less attractive properties.
The present invention seeks to provide a solution to this problem.
According to one aspect of the present invention, there is provided a catalyst composition for producing alpha-olefin polymers or copolymers, comprising:
(1) a metallocene, wherein the metallocene has the formula: CpmMAnBp, wherein Cp is a cyclopentadienyl or a substituted cyclopentadienyl group; m is 1 or 2; M is titanium, zirconium or hafnium; and each of A and B is selected from the group consisting of a halogen atom, a hydrogen atom and an alkyl group, providing that m+n+p is equal to the valency of the metal M;
(2) an inorganic aluminum compound Al(OH)xOy, wherein x is a number from 0 to 3, wherein x+2y=3; and
(3) trimethylaluminum, wherein the Al(0H)x0y is used in an amount sufficient to provide and an Al(OH)x0y:metallocene molar ratio of 5 to 10,000; the trimethylaluminum is used in an amount sufficient to provide a trimethylaluminum:metallocene molar ratio of 50 to 10,000; and the Al(0H)x0y and the trimethylaluminum are used in amounts to provide a molar ratio of trimethylaluminum to Al(0H)x0y in the range of from 0.1 to 100.
Preferably, the Al(0H)x0y is A1(0H)3 or A1(0)0H. Preferably, the metallocene is biscyclopentadienylzirconium dichloride; or biscyclopentadienyltitanium dichloride. The catalyst may be supported or unsupported, but in a most preferred embodiment, the catalyst is a supported catalyst in which the metallocene is supported on a carrier, which is porous and has a particle size of 1 to 500 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of 0.5 to 5.0 cm3/g.
According to another aspect of the present invention, there is provided a process for preparing a catalyst for producing alpha-olefin polymers or copolymers, said process comprising the steps of: (i) preparing a catalyst precursor by providing silica which is porous and has a particle size of 1 to 200 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of
0.5 to 5.0 cm3/g, and impregnating said silica with at least one metallocene compound of the formula
CpmMAnBp, wherein Cp is a cyclopentadienyl or a substituted cyclopentadienyl group, m is 1 or 2, M is titanium, zirconium or hafnium, and each of A and B is selected from the group consisting of a halogen atom, a hydrogen atom and an alkyl group, providing that m+n+p is equal to the valency of the metal M; and ii) combining the impregnated catalyst precursor (i) with a combination of: an inorganic aluminum compound
Al(OH)xOy, wherein x is a number from 0 to 3, wherein x+2y=3 and trimethylaluminum; wherein the Al(OH)xOy is used in an amount sufficient to provide an Al(OH)x0y:metallocene molar ratio of 5 to 10,000; the trimethylaluminum is used in an amount sufficient to provide a trimethylaluminum:metallocene molar ratio of 50 to 10,000; and the wherein the Al(0H)x0y and the trimethylaluminum are used in amounts to provide a molar ratio of trimethylaluminum to
Al(OH)xOy in the range of from 0.1 to 100.
In an especially preferred embodiment the mixture of trimethylaluminum and Al(OH)x.Oy is subjected to ultrasonic irradiation prior to combining it with the catalyst precursor.
It is preferred that the transition metal atom M in the metallocene compound is zirconium.
In the above formula of the metallocene compound, the Cp group is an unsubstituted, a mono- or a polysubstituted cyclopentadienyl group. The substituents on the cyclopentadienyl group may be straight-chain Cj-C6 alkyl groups.
The cyclopentadienyl group can be also a part of a bicyclic or a tricyclic moiety such as indenyl, tetrahydroindenyl, fluorenyl or a partially hydrogenated fluorenyl group, as well as a part of a substituted bicyclic or tricyclic moiety. In the case when m in the above formula of the metallocene compound is equal to
2, the cyclopentadienyl groups can be also bridged by alkyl groups, such as -CH2-, -CH2-CH2-, -CR'R"- and -CR'R"-CR'R"-, where R' and R" are short alkyl groups or hydrogen atoms; or dialkylsilane groups, such as -Si(CH3)2-, Si(CH3)2-CH2-CH2-
Si(CH3)2- and similar bridge groups. Bridged cyclopentadienyl complexes are used for stereospecific polymerization of propylene. If the A and B substituents in the above formula of the metallocene compound are halogen atoms, they belong to the group of fluorine, chlorine, bromine or iodine. If the substituents A and B in the above formula of the metallocene compound are alkyl groups, they are preferably straight-chain or branched Cj-Cg alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl or n-octyl.
Suitable metallocene compounds include: bis (cyclopentadienyl)metal dihalides; bis (cyclopentadienyl) metal hydridohalides ; bis (cyclopentadienyl) metal monoalkyl monohalides; bis (cyclopentadienyl)metal dialkyls;and bis (indenyl) metal dihalides, wherein the metal is titanium, zirconium or hafnium, and the halide atoms are preferably chlorine, and the alkyl groups are preferably Cj-C,^ Illustrative, but non-limiting examples of metallocenes include: bis (cyclopentadienyl) zirconium dichloride; bis (cyclopentadienyl) hafnium dichloride; bis (cyclopentadienyl ) titanium dichloride; bis (cyclopentadienyl) zirconium dimethyl ; bis (cyclopentadienyl) hafnium dimethyl; bis (cyclopentadienyl) zirconium hydridochloride; bis (cyclopentadienyl) hafnium hydridochloride; biε(n- butylcyclopentadienyl) zirconium dichloride; bis(n- butylcyclopentadienyl) hafnium dichloride; bis(n- butylcyclopentadienyl) zirconium dimethyl; bis(n- butylcyclopentadienyl) hafnium dimethyl; bis(n- butylcyclopentadienyl) zirconium hydridochloride bis (n-butylcyclopentadienyl) hafnium hydridochloride bis(pentamethylcyclopentadienyl) zirconium dichloride bis (pentamethylcyclopentadienyl) hafnium dichloride bis (pentamethylcyclopentadienyl) titanium dichloride cyclopentadienyl zirconium trichloride cy c 1 opent adi eny 1 t i t an ium trichloride bis (indenyl) zirconium dichloride; bis(4, 5,6,7- tetrahydro-1-indenyl) zirconium dichloride; and ethylene-[bis(4,5,6,7-tetrahydro-1-indenyl) ]zirconium dichloride. The metallocene compounds utilized within the embodiment of this art can be used as crystalline solids, as solutions in aromatic hydrocarbons or in a supported form.
As explained above, if the metallocene is supported, the support carrier material is a particulate, porous, solid such as an oxide of silicon and/or of aluminum, or a crosslinked polymer, e.g. polystyrene. Preferably, it is an inorganic material. The carrier material can be used in the form of a dry powder and has an average particle size of from 1 to 500 microns, preferably from 1 to 250 microns, more preferably from 10 to 150 microns. The surface area of the carrier is preferably at least 50 m2/g up to 350 m2/g. The carrier material should preferably be dry, i.e., free of absorbed water. Drying of the inorganic carrier material can be effected by heating at about 100°C to about 1000°C, preferably at about 600°C. When the carrier is silica, it is preferably heated to at least 200°C, preferably about 200°C to about 850°C and most preferably at about 600°C.
In the most preferred embodiment, the carrier is silica which, prior to the use thereof in the catalyst synthesis, has been dehydrated by fluidizing it with nitrogen and heating at about 600°C for about 4 to 16 hours. The silica of the most preferred embodiment is a high surface area, amorphous silica with a surface area of 300 m2/g and a pore volume of 1.65 cm3/g.
Supporting of a metallocene compound on a carrier is undertaken by dissolving the metallocene in a solvent under anhydrous conditions, slurrying the carrier in the solvent containing the metallocene in order to impregnate the carrier with the metallocene, and removing the solvent to recover a dry particulate supported metallocene. Slurrying and contact of metallocene solution with a support can be undertaken at temperatures ranging from 20 to 60°C, preferably 30 to 55°C. Solvent removal, after the impregnation, may be undertaken at a temperature up to 60°C, with or without a nitrogen purge. The solvent in this step may be an aromatic, aliphatic or The solvent in this step may be an aromatic, aliphatic or chlorinated hydrocarbon, an ether, a cyclic ether, an ester, or a ketone. The loading of the metallocene on the support is in the range of 0.1 to 1.0 grams per gram of support, preferably 0.25 to 0.45 grams per gram of support.
For activation, the unsupported or supported metallocene, in slurry or in solution is then contacted with Al(OH)xOy and TMA.
The Al(OH)xOy, is a solid inorganic compound containing aluminum and oxygen atoms and hydroxyl groups and with x in the range from 0 to 3, wherein x+2y=3. These compounds include Al(OH)3, A1(0)0H and A1203. These solids should not contain water, either in a free or an adsorbed form. The amount of TMA in the cocatalyst composition is sufficient to give an Al:metallocene molar ratio of about 50 to about 10,000, preferably about 100 to about 1,000.
TMA and the inorganic aluminum compound Al(OH)xOy can be used to contact the metallocene compound separately or as a mixture. Contact with the metallocene can be undertaken in the polymerization reactor by feeding either one or the other of TMA and Al(OH)xOy seriatim to the reactor or feeding a mixture comprising TMA and Al(OH)xOy to the polymerization reactor. Alternatively, activation of the metallocene can be undertaken prior to introduction of the activated catalyst into the polymerization reactor by contacting either one or the other of TMA and Al(OH)xOy seriatim with the metallocene or contacting the metallocene with a mixture comprising TMA and Al(OH)xOy for up to about 2 hours prior to the introduction thereof into the polymerization medium at a temperature of from about -40 to about 100°C. Activity of the cocatalysts can be increased by reacting TMA and the inorganic aluminum compound at elevated temperatures or by subjecting the binary mixture of TMA and the inorganic aluminum compound to ultrasonic irradiation.
The catalyst synthesis of the present invention is undertaken in the substantial absence of water, oxygen, and other catalyst poisons. Such catalyst poisons can be excluded during the catalyst preparation steps by any well known methods, nitrogen, argon or other inert gas.
The polymerization processes, with which the catalyst according to the invention can be used, will now be described.
Alpha-olefins can be polymerized with the catalysts prepared according to the present invention by any suitable process. Such processes include polymerizations carried out in suspension, in solution or in the gas phase.
The molecular weights of the polymers may be controlled in a known manner, e.g., by using hydrogen when the polymerization is carried out at temperatures from about 30 to about 105°C. Pressures used in polymerization reactions are preferably above ambient and below 1000 psi (6.9 MPa) , more preferably below 400 psi (2.8 MPa) and most preferably from 100 to 350 psi (690 KPa to 2.4 MPa). When the catalyst of the invention is used in solution or in slurry polymerizations, aromatic solvents (e.g., toluene) and aliphatic solvents (e.g. heptane) can constitute the polymerization medium.
Linear ethylene polymers can be prepared using the catalyst according to the invention. These polymers may be homopolymers of ethylene or copolymers of ethylene with one or more C3-C10 alpha-olefins. Thus, copolymers having two monomeric units are possible as well as terpolymers having three monomeric units. Particular examples of such polymers include ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1-octene copolymers, ethylene/4-methyl-l-pentene copolymers, ethylene/1- butene/1-hexene terpolymers, ethylene/propylene/1-hexene terpolymers and ethylene/propylene/1-butene terpolymers. The most preferred comonomers are 1-butene and 1-hexene. The linear low density polyethylene polymers produced in accordance with the present invention preferably contain at least about 80 percent by weight of ethylene units. It is also possible to polymerize propylene with the metallocene catalysts of the invention to produce stereoregular products. EXAMPLES Example 1
A stainless-steel autoclave (volume 500 cm3) equipped with a stirrer, a thermocouple and several ports for adding reaction components was purged with dry nitrogen and filled with 200 cm3 of dry n-heptane and 50 cm3 of 1-hexene, after which 5 cm3 of 20 wt.% solution of A1(CH3)3 in heptane and 0.2 g of Al(OH)3 were added to the reactor. Temperature was raised to 70°C and 0.5 cm3c of a solution of (C5H5)2ZrCl2 in toluene containing 1.710"3 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 60 min to yield 26.0 g of ethylene/1- hexene copolymer with a hexene content of 1.9 mol.% and an I2 value of 1.1.
Example 2
First, the cocatalyst preparation will be described. An ultrasonic tool (Lab-Line Ultra Tip with a diameter of 12.5 mm, a part of a Labsonic Systems ultrasonic apparatus) was inserted into a 15 cm3 three-necked glass flask through its central 18 mm diameter inlet and was secured in the flask with a rubber collar. 0.20 g of Al(OH)3 was added to the flask through one of its two side inlets, after which both side inlets were capped with rubber septums and the flask was purged with dry nitrogen for 15 min. Then 10 cm3 of dry toluene and 5 cm3 of 20 wt.% solution of A1(CH3)3 in heptane was added to the flask with syringes through one of the septums and the slurry was irradiated with ultrasound (ca. 20 watt power) for 5 min. The reaction produced a large volume of gaseous products which escaped through a needle inserted in one of the septums.
The polymerization will now be described. An autoclave (the same as in Example 1) was purged with nitrogen and filled with 200 cm3 of dry heptane and 50 cm3 of 1-hexene, after which all contents of the flask used for preparation of the cocatalyst system, about 15 cm3, was transferred into the reactor. The temperature was raised to 70°C and 0.5 cm3 of a solution of (C5H5)2ZrCl2 in toluene containing 1.7103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 30 min to yield 24.2 g of ethylene/1-hexene copolymer with a hexene content of 2.3 mol.% and a I2 value of 9.2. Measurements of the ethylene consumption rates with a gas flow-meter during this polymerization experiment showed that the polymerization rate was 60% higher than in Example 1 in which no ultrasonic irradiation was applied to the cocatalyst system.
Example 3
An autoclave (the same as in Example 1) was purged with dry nitrogen and filled with 200 cm3 of dry n-heptane and 50 cm3 of 1-hexene, after which 2 cm3 of 20 wt% solution of A1(CH3)3 in heptane and 0.1 g of Al(OH)3 were added to the reactor. Temperature was raised to 70°C and 0.25 cm3 of a solution of (n-C4H9-C5H4)2ZrCl2 in toluene containing 6.2104 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 24.1 g of ethylene/hexene copolymer with a hexene content of 2.6 mol% and an I2 value of 3.2.
Example 4
The cocatalyst was prepared as follows. To an autoclave (the same as in Example 1) were added 0.10 g of Al(OH)3, 10 cm3 of dry toluene and 2 cm3 of 15.5 wt.% solution of A1(CH3)3 in toluene. Reactor temperature was increased to 150°C, the mixture reacted at this temperature for 2 hours and then was cooled to 25°C. The polymerization was carried out as follows. 250 cm3 of dry hexane and 50 cm3 of dry 1-hexane were added to the reactor, its temperature was raised to 70°C and 1 cm3 of a solution of (n-C4H9-C5H4)2ZrCl2 in toluene containing 2.5104 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 27.6 g of ethylene/hexene copolymer with a hexene content of 2.8 mol % and an I2 value of 0.45.
Example 5
An autoclave (the same as in Example 1) was filled with 200 cm3 of dry n-heptane and 50 cm3 of 1-hexene, after which 2 cm3 of 20 wt.% solution of A1(CH3)3 in heptane and 0.1 g of A1(0H)3 were added to the reactor. Temperature was raised to 70°C and 0.5 cm3 of a solution of (CH3-C5H4)2ZrCl2 in toluene containing 1.6103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 Mpa) and a polymerization reaction was continued for 120 min to yield 18.9 g of ethylene/1-hexane copolymer with a hexene content of 2.1 mol% and an I2 value of 14.9.
Example 6
An autoclave (the same as in Example 1) was filled with 200 cm3 of dry n-heptane and 50 cm3 of 1-hexene, after which 2 cm3 of 20 wt% solution of A1(CH3)3 in heptane and 0.2 g of A1(0H)3 were added to the reactor. Temperature was raised to 70°C and 4.0 cm3 of a solution of ethylene-bis(idenyl)ZrCl2 in toluene containing 4.9104 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 90 min to yield 6.8 g of ethylene/1-hexene copolymer with a hexene content of 5.8 mol% and an I2 value of 21.
Example 7
A zirconocene-based supported catalyst was prepared by reacting 1.0 g of silica dehydrated at 600°C and a solution of 0.080 g of (C5H5)2ZrCl2 in 10 cm3 of dry tetrahydrofuran for 10 min after which the solvent was stripped from the solid catalyst slurry by nitrogen purge at 70°C for 2 h. An autoclave (the same as in Example 1) was filled with 200 cm3 of dry n-heptane and 50 cm3 of 1-hexene after which 2 cm3 of 20 wt.% solution of A1(CH3)3 in heptane and 0.2 g of A1(0H)3 were added to the reactor. Temperature was raised to 70°C and 0.0268 g of the above catalyst was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 60 min to yield 10.2 g of ethylene/1-hexene copolymer with a hexene content of 1.7 mol.% and an I2 value of 0.50.
Example 8
An autoclave (the same as in Example 1) was filled with 200 cm3 of dry n-heptane and 50 cm3 of 1-hexene, after which 4 cm3 of 20 wt% solution of A1(CH3)3 in heptane and 0.35 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 1.0 cm3 of a solution of (C5H5)2ZrCl2 in toluene containing 3.4103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 Mpa) and a polymerization reaction was continued for 210 min to yield 26.4 g of ethylene/1-hexene copolymer with a hexene content of 3.0 mol% and an I2 value of 4.3.
Example 9
An autoclave (the same as in Example 1) was filled with 100 cm3 of dry toluene and 25 cm3 of 1-hexene, after which 4 cm3 of 20 wt% solution of A1(CH3)3 in heptane and 0.35 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 0.5 cm3 of a solution of (n-C4H9-C5H4)2ZrCl2 in toluene containing 1.2103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 14.4 g of ethylene/1-hexene copolymer with a hexene content of 0.9 mol% and an I2 value of 1.8.
Example 10
An autoclave (the same as in Example 1) was filled with 200 cm3 of dry toluene and 50 cm3 of 1-hexene, after which 4 cm3 of 20 wt% solution of A1(CH3)3 in heptane and 0.50 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 1.0 cm3 of a solution of (C5H5)2Zr(CH3)2 in toluene containing 3.3103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 Mpa) and a polymerization reaction was continued for 120 min to yield 28.5 g of ethylene/1-hexene copolymer with a hexene content of 2.6 mol% and an I2 value of 2.5.
Example 11
An autoclave (the same as in Example 1) was filled with 200 cm3 of dry toluene and 50 cm3 of 1-hexene, after which 4 cm3 of 20 wt% solution of A1(CH3)3 in heptane and 0.50 g of A1(0)0H were added to the reactor. Temperature was raised to 70°C and 1.0 cm3 of a solution of (C5H5)2TiCl2 in toluene containing 4.0103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 17.0 g of ethylene/1-hexene copolymer with a hexene content of 4.0 mol% hexene.
Example 12
The cocatalyst was prepared as follows. A 15cm3 three- necked glass flask was equipped with an ultrasonic tool described in Example 2 and 0.29 g of A1(0)0H was placed in it. Then 10 cm3 of dry toluene and 5 cm3 of 20 wt.% solution of A1(CH3)3 in heptane was added to the flask and the slurry was irradiated with ultrasound (ca. 30 watt power) for 5 min.
The polymerization was carried out as follows. An autoclave (the same as in Example 1) was filled with 200 cc of dry toluene and 50 cm3 of 1-hexene, after which all contents of the flask used for preparation of the cocatalyst system, about 15 cm3, was transferred into the reactor. The temperature was raised to 70°C and 0.5 cm3 of a solution of (C5Hs) ZrCl2 in toluene containing 1.7103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 50 min to yield 16.7 g of ethylene/1-hexene copolymer with a hexene content of 2.6 mol% and an I2 value of 14.9. Measurements of ethylene consumption rates with a gas flow-meter during this polymerization experiment showed that the polymerization rate was 260% higher than in a similarly performed experiment in which no ultrasonic irradiation was applied to the cocatalyst syste . Example 13
The cocatalyst was prepared as follows. To an autoclave (the same as in Example 1) were added 0.10 g of A1(0)0H, 10 cm3 of dry toluene and 2 cm3 of 15.5 wt.% solution of A1(CH3)3 in toluene. Reactor temperature was increased to 150°C, the mixture reacted at this temperature for 2 hours and then was cooled to 25°C. The polymerization was carried out as follows. 250 cm3 of dry hexane and 50 cm3 of dry 1-hexene were added to the reactor, its temperature was raised to 70°C and 1 cm3 of a solution of (n-C4H9-C5H4)2ZrCl2 in toluene containing 2.5103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 9.5 g of ethylene/hexene copolymer with a hexene content of 3.4 mol.% and an I2 value of 43.
Example 14
The cocatalyst was prepared as follows. To an autoclave (the same as in Example 1) were added 0.10 g of A1203, 10 cm3 of dry toluene and 2 cm3 of 15.5 wt.% solution of A1(CH3)3 in toluene. Reactor temperature was increased to 150°C, the mixture reacted at this temperature for 2 hours and then was cooled to 25°C.
The polymerization was carried out as follows. 250 cm3 of dry hexane and 50 cm3 of dry 1-hexene were added to the reactor, its temperature was raised to 70°C and 1 cc of a solution of (n- C4H9-C5H4)2ZrCl2 i-n toluene containing 2.5104 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and the polymerization was continued for 120 min to yield 3.5 g of ethylene/hexene copolymer with a hexene content of 2.0 mol.% and an I2 value of 0.13. Example 15
The gas phase polymerization was carried out as follows. An autoclave (the same as in Example 1) was filled with 30 g of degassed crystalline polypropylene which served as a polymerization medium. 6 cm3 of 1-hexane, 0.33 g of A1(0H)3 and 3 cm3 of 20 wt.% solution of A1(CH3)3 in heptane was added to the reactor and temperature was raised to 70°C. After that, 0.071 g of the supported catalyst described in Example 8 was introduced into the reactor. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 120 min to yield 26.3 g of ethylene/1-hexene copolymer.
Comparative Example 1 First, an evaluation of possible cocatalyst contamination with methylaluminoxane was carried out. All inorganic compounds of aluminum of this invention may contain occluded or absorbed water. This possibility is the highest in the case of A1(0H)3 and is lower for A1(0)0H or Al203. Interaction between water and A1(CH3)3 is known to produce methylaluminoxane, which is an efficient cocatalyst for metallocenes. To evaluate possible contamination of the cocatalyst systems of this invention with methylaluminoxane, a use was made of the fact that methylaluminoxane is soluble in aromatic solvents such as toluene whereas the cocatalyst systems of this invention are not soluble in these solvents.
The cocatalyst was prepared as follows. In a 40 cm3 centrifuge flask capped with a septum, 0.10 g of A1(0H)3 was slurried in 5 cm3 of dry toluene, and 1 cm3 of 15.5 wt.% solution of A1(CH3)3 in toluene was added to it resulting in evolution of gaseous products. The slurry was reacted at 50°C for 4 hours. After that the slurry was centrifuged and the whole liquid fraction of it was withdrawn from the flask with a syringe and was used as Cocatalyst A. The solid remaining in the flask was reslurried in 5 cm3 of dry toluene and was used as cocatalyst B.
The polymerization was carried out as follows. In two separate experiments, an autoclave (the same as in Example 1) was filled with 200 cm3 of dry n-heptane and 50 cm3 of 1-hexene, after which 1 cm3 of A1(CH3)3 solution in heptane was added to it to purify the reaction medium. Polymerization Experiment A. Clear liquid produced in the cocatalyst preparation step was added to the reactor, temperature was raised to 70°C and 0.5 cm3 of a solution of (C5H5)2ZrCl2 in toluene containing 1.7103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 60 min. Less than 2 g of a solid product was recovered.
Polymerization Experiment B. The slurry of white powder produced in the cocatalyst preparation step was added to the reactor, temperature was raised to 70°C and 0.5 cm3 of a solution of (C5H5)2ZrCl2 in toluene containing 1.7103 mmol Zr was introduced. Ethylene was added to the reactor to a total pressure of 180 psig (1.3 MPa) and a polymerization reaction was continued for 60 min. 29.7 g of ethylene/1-hexene copolymer was recovered. This example demonstrated that contamination of the cocatalyst systems of this invention with methylaluminoxane due to a possible presence of water in the inorganic compounds of aluminum in negligible.

Claims

Claims
1. A catalyst composition for producing alpha-olefin polymers or copolymers, comprising: (1) a metallocene, wherein the metallocene has the formula: CpmMAnBp, wherein Cp is a cyclopentadienyl or a substituted cyclopentadienyl group; m is 1 or 2; M is titanium, zirconium or hafnium; and each of A and
B is selected from the group consisting of a halogen atom, a hydrogen atom and an alkyl group, providing that m+n+p is equal to the valency of the metal M;
(2) an inorganic aluminum compound Al(0H)x0y, wherein x is a number from 0 to 3, wherein x+2y=3; and
(3) trimethylaluminum, wherein the Al(0H)x0y is used in an amount sufficient to provide and an Al(0H)x0y:metallocene molar ratio of 5 to 10,000; the trimethylaluminum is used in an amount sufficient to provide a trimethylaluminum:metallocene molar ratio of 50 to 10,000; and the Al(OH)xOy and the trimethylaluminum are used in amounts to provide a molar ratio of trimethylaluminum to Al(0H)x0y in the range of from 0.1 to 100.
2. A catalyst composition according to Claim 2, wherein the Al(0H)x0y is A1(0H)3 or A1(0)0H.
3. A catalyst composition according to Claim 1 or 2, wherein the metallocene is selected from the group consisting of bis (cyclopentadienyl) z irconium dichloride bis (cyclopentadienyl) hafnium dichloride bis ( cyclopentadienyl ) titanium dichloride bis (cyclopentadienyl) z irconium dimethyl bis (cyclopentadienyl) hafnium dimethyl bis (cyclopentadienyl) zirconium hydridochloride bis (cyclopentadienyl) hafnium hydridochloride bis (pentamethylcyclopentadienyl) titanium dichloride bis (pentamethylcyclopentadienyl) zirconium dichloride bis (pentamethylcyclopentadienyl) hafnium dichloride bis(n-butylcyclopentadieny1) zirconium dichloride; cyclopentadienyl-zirconium trichloride; cyclopentadienyltitanium trichloride; bis(indenyl)zirconium dichloride; bis(4,5,6,7- tetrahydro-1-indenyl)zirconium dichloride; and ethylene-[bis(4,5,6,7-tetrahydro-l-indenyl) ]zirconium dichloride.
4. A catalyst composition according to Claim 1, 2 or 3, wherein said metallocene is supported on a carrier, which is porous and has a particle size of 1 to 500 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of 0.5 to 5.0 cm3/g.
5. A catalyst composition according to Claim 4, wherein the carrier is a silica carrier.
6. A catalyst composition according to any one of the preceding Claims, wherein the metallocene is: biscyclopentadienylzirconium dichloride; or biscyclopentadienyltitanium dichloride.
7. A process for preparing a catalyst for producing alpha- olefin polymers or copolymers, said process comprising the steps of:
(i) preparing a catalyst precursor by providing silica which is porous and has a particle size of 1 to 200 microns, having pores which have an average diameter of 50 to 500 Angstroms and having a pore volume of 0.5 to 5.0 cm3/g, and impregnating said silica with at least one metallocene compound of the formula CpmMAnBp, wherein Cp is a cyclopentadienyl or a substituted cyclopentadienyl group, m is 1 or 2, M is titanium, zirconium or hafnium, and each of A and B is selected from the group consisting of a halogen atom, a hydrogen atom and an alkyl group, providing that m+n+p is equal to the valency of the metal M; and ii) combining the impregnated catalyst precursor (i) with a combination of: an inorganic aluminum compound Al(0H)x0y, wherein x is a number from 0 to 3, wherein x+2y=3 and trimethylaluminum; wherein the Al(0H)x0y is used in an amount sufficient to provide an Al(OH)xOy:metallocene molar ratio of 5 to 10,000; the trimethylaluminum is used in an amount sufficient to provide a trimethylaluminum:metallocene molar ratio of 50 to 10,000; and the wherein the Al(OH)xOy and the trimethylaluminum are used in amounts to provide a molar ratio of trimethylaluminum to Al(OH)xOy in the range of from 0.1 to 100.
8. A process according to Claim 7 wherein the Al(0H)x0y is A1(0H)3 or A1(0)0H.
9. A process according to Claim 7 or 8, wherein the metallocene compound is selected from the group consisting of: bis (cyclopentadienyl)metal dihalides; bis (cyclopentadienyl)metal hydridohalides; bis(cyclopentadienyl)metal monoalkyl monohalides; bis (cyclopentadienyl) metal dialkyls; and bis(indenyl)metal dihalides, wherein the metal is titanium, zirconium or hafnium.
10. A process according to Claim 9, wherein the metallocene compound is selected from the group consisting of bis ( cyclopentadienyl) zirconium dichloride bis ( cyclopentadieny 1 ) hafnium dichloride bis (cyclopentadienyl) z irconium dimethyl bis (cyclopentadienyl) titanium dichloride bis (cyclopentadienyl) hafnium dimethy 1 bis (cyclopentadienyl) zirconium hydridochloride bis (cyclopentadienyl) hafnium hydridochloride bis (pentamethylcyclopentadienyl) zirconium dichloride bis (pentamethylcyclopentadienyl) titanium dichloride bis (pentamethylcyclopentadienyl) hafnium dichloride bis(n-butylcyclopentadienyl) zirconium dichloride cyclopentadienyl-zirconium trichloride cyclopentadienyltitanium trichloride bis (indenyl) zirconium dichloride; bis (4, 5,6,7- tetrahydro-1-indenyl) zirconium dichloride; and ethylene- [bis (4,5,6, 7-tetrahydro-l-indenyl) ] zirconium dichloride.
11. A process according to any one of Claims 7 to 10, wherein the mixture of trimethylaluminum and Al(0H)x0y is subjected to ultrasonic irradiation prior to combining it with the catalyst precursor.
12. A process for polymerizing an alpha-olefin comprising polymerizing said alpha olefin under polymerization conditions in the presence of a catalyst composition as defined in any one of Claims 1 to 7.
PCT/US1994/013434 1993-11-18 1994-11-17 Catalyst for preparing alpha-olefin polymers and copolymers WO1995013872A1 (en)

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EP1062040A4 (en) * 1997-12-18 2005-01-19 Exxonmobil Oil Corp Olefin polymerisation catalyst based on metallocene complexes and perfluorinated oligoaryl derivatives of aluminates

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US5077255A (en) * 1986-09-09 1991-12-31 Exxon Chemical Patents Inc. New supported polymerization catalyst
US5171799A (en) * 1988-09-14 1992-12-15 Mitsui Petrochemical Industries, Ltd. Olefin polymerization catalyst component, olefin polymerization catalyst and process for the polymerization of olefins
US5223465A (en) * 1990-03-16 1993-06-29 Tonen Corporation Olefin polymerization catalyst

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Publication number Priority date Publication date Assignee Title
US5077255A (en) * 1986-09-09 1991-12-31 Exxon Chemical Patents Inc. New supported polymerization catalyst
US5171799A (en) * 1988-09-14 1992-12-15 Mitsui Petrochemical Industries, Ltd. Olefin polymerization catalyst component, olefin polymerization catalyst and process for the polymerization of olefins
US5223465A (en) * 1990-03-16 1993-06-29 Tonen Corporation Olefin polymerization catalyst

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1062040A4 (en) * 1997-12-18 2005-01-19 Exxonmobil Oil Corp Olefin polymerisation catalyst based on metallocene complexes and perfluorinated oligoaryl derivatives of aluminates

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