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WO1998037103A1 - Production de polyolefines dont les particules presentent une dimension commandee - Google Patents

Production de polyolefines dont les particules presentent une dimension commandee Download PDF

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Publication number
WO1998037103A1
WO1998037103A1 PCT/US1998/003329 US9803329W WO9837103A1 WO 1998037103 A1 WO1998037103 A1 WO 1998037103A1 US 9803329 W US9803329 W US 9803329W WO 9837103 A1 WO9837103 A1 WO 9837103A1
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Prior art keywords
catalyst
group
liquid droplets
polymerization reactor
reactor
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PCT/US1998/003329
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English (en)
Inventor
Clark Curtis Williams
Timothy Roger Lynn
Mark Gregory Goode
Robert Converse Brady, Iii
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Union Carbide Chemicals & Plastics Technology Corporation
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Priority to AU61787/98A priority Critical patent/AU6178798A/en
Publication of WO1998037103A1 publication Critical patent/WO1998037103A1/fr

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    • 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
    • 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
    • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
    • 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

Definitions

  • the present invention relates to controlling the average particle size of polyolef ⁇ ns produced using unsupported catalysts in gas phase polymerization.
  • Unsupported, liquid catalysts offer many advantages over conventional solid-supported catalysts. Unsupported catalysts require less equipment and raw materials to make them and impart fewer impurities to the final polymer product. The activity of an unsupported catalyst is not adversely influenced by the surface area of a support material. Additional advantages are encountered when a high-activity, unsupported metallocene catalyst is used for polymerizations in a fluidized bed reactor.
  • a droplet of unsupported catalyst solution is introduced into a gas phase reactor such as a fluidized bed reactor
  • several simultaneous or rapid processes can occur, including droplet heating, solvent evaporation, solute (catalyst and/or cocatalyst) precipitation, monomer and comonomer diffusion, and polymerization.
  • the rate of heat generation due to polymerization can increase the particle temperature to above that of the average fluidized bed temperature, resulting in particle melting or softening to the point of excessive agglomerating or fusing of particles. This can often occur shortly after the droplet has been introduced into the reactor because of the rapid heat generation at the onset of polymerization. Polymer particles can grow so large that they cannot be fluidized thereby causing the reactor to be shut down.
  • Copending U.S. Application Serial No. 08/659,764 filed June 6, 1996 relates to one method of controlling the growth of polyolefin polymer particles made using an unsupported catalyst during gas phase polymerization.
  • the unsupported catalyst is introduced into the reactor into a particle lean zone substantially free of resin. This allows a brief period of time for droplets containing the unsupported catalyst to undergo evaporation before contacting the polymer particles already in the reactor, reducing the tendency for excessive agglomeration of polymer particles.
  • the average particle size of a polyolefin produced using an unsupported catalyst in gas phase polymerization is also well controlled by adjusting at least one of: a) the size of the liquid droplets containing the catalyst introduced into the polymerization reactor, and b) the concentration of catalyst composition in the liquid droplets.
  • This technique provides a relatively simple method, readily carried out using manual or computer operated process control, for controlling particle size in the reactor.
  • neither reactor stability nor production rates are adversely effected.
  • the invention provides a process for producing a polyolefin in a gas phase polymerization reactor, which comprises: (i) introducing monomer into the polymerization reactor;
  • Polymers Illustrative of the polymers which can be produced in accordance with the invention are the following: ethylene homopolymers and ethylene copolymers employing one or more C3-C12 alpha olefins; propylene homopolymers and propylene copolymers employing one or more C4-C12 alpha olefins; polyisoprene; polystyrene; polybutadiene; polymers of butadiene copolymerized with styrene; polymers of butadiene copolymerized with acrylonitrile; polymers of isobutylene copolymerized with isoprene; ethylene propylene rubbers and ethylene propylene diene rubbers; polychloroprene, and the like.
  • the present invention is not limited to any specific type of gas phase polymerization reaction and can be carried out in a stirred or fluidized bed reactor.
  • the invention can be carried out in a single reactor or multiple reactors (two or more reactors in series).
  • "condensed mode” including the so-called “induced condensed mode”
  • "liquid monomer” operation of a gas phase polymerization can be employed.
  • a conventional fluidized bed process for producing resins is practiced by passing a gaseous stream containing one or more monomers continuously through a fluidized bed reactor under reactive conditions in the presence of a polymerization catalyst. Product is withdrawn from the reactor. A gaseous stream of unreacted monomer is withdrawn from the reactor continuously and recycled into the reactor along with make-up monomer added to the recycle stream.
  • Condensed mode polymerizations are disclosed in U.S. Patent Nos. 4,543,399; 4,588,790; 5,352,749; and 5,462,999. Condensing mode processes are employed to achieve higher cooling capacities and, hence, higher reactor productivity.
  • a recycle stream, or a portion thereof can be cooled to a temperature below the dew point in a fluidized bed polymerization process, resulting in condensing all or a portion of the recycle stream.
  • the recycle stream is returned to the reactor.
  • the dew point of the recycle stream can be increased by increasing the operating pressure of the reaction/recycle system and/or increasing the percentage of condensable fluids and decreasing the percentage of non-condensable gases in the recycle stream.
  • the condensable fluid may be inert to the catalyst, reactants and the polymer product produced; it may also include monomers and comonomers.
  • the condensable fluid can be introduced into the reaction/recycle system at any point in the system.
  • condensable fluids of the polymerization process itself may be used or other condensable fluids inert to the polymerization can be introduced to "induce" condensing mode operation.
  • suitable condensable fluids may be selected from liquid saturated hydrocarbons containing 2 to 8 carbon atoms (e.g., propane, n-butane, isobutane, n- pentane, isopentane, neopentane, n-hexane, isohexane, and other saturated C6 hydrocarbons, n-heptane, n-octane and other saturated C ⁇ and Cg hydrocarbons, and mixtures thereof). Unsaturated hydrocarbons may also be used.
  • Condensable fluids may also include polymerizable condensable comonomers such as olefins, alpha-olefins, diolefins, diolefins containing at least one alpha olefin, and mixtures thereof. In condensing mode, it desirable that the liquid entering the fluidized bed be dispersed and vaporized quickly.
  • Liquid monomer polymerization mode is disclosed in U.S. Patent No. 5,453,471, U.S. Serial No. 510,375, PCT WO95/09826 and PCT WO95/09827.
  • liquid monomer present in the bed is adsorbed on or absorbed in solid particulate matter present in the bed, such as polymer being produced or fluidization aids (e.g., carbon black) present in the bed, so long as there is no substantial amount of free liquid monomer present more than a short distance above the point of entry into the polymerization zone.
  • Liquid mode makes it possible to produce polymers in a gas phase reactor using monomers having condensation temperatures much higher than the temperatures at which conventional polyolefins are produced.
  • liquid monomer process are conducted in a stirred bed or gas fluidized bed reaction vessel having a polymerization zone containing a bed of growing polymer particles.
  • the process comprises continuously introducing a stream of one or more monomers and optionally one or more inert gases or liquids into the polymerization zone; continuously or intermittently introducing a polymerization catalyst into the polymerization zone; continuously or intermittently withdrawing polymer product from the polymerization zone; and continuously withdrawing unreacted gases from the zone; compressing and cooling the gases while maintaining the temperature within the zone below the dew point of at least one monomer present in the zone.
  • the temperature within the zone and the velocity of gases passing through the zone are such that essentially no liquid is present in the polymerization zone that is not adsorbed on or absorbed in solid particulate matter.
  • Monomers that can be employed in the process include one or more C2 to C12 alpha-olefins; dienes such as those taught in U.S. Patent No. 5,317,036 to Brady et al. such as hexadiene, dicyclopentadiene, norbornadiene, and ethylidene norbornene; readily condensable monomers such as those taught in U.S. Patent No. 5,453,471 including isoprene, styrene, butadiene, isobutylene, and chloroprene, acrylonitrile, and the like.
  • inert particulate Materials can include carbon black, silica, talc, and clays, as well as inert polymeric materials.
  • Carbon black has a primary particle size of about 10 to about 100 nanometers, an average size of aggregate of about 0.1 to about 10 micrometers, and a specific surface area of about 30 to about 1,500 m ⁇ /gm.
  • Silica has a primary particle size of about 5 to about 50 nanometers, an average size of aggregate of about 0.1 to about 10 micrometers, and a specific surface area of about 50 to 500 m ⁇ /gm.
  • Clay, talc, and polymeric materials have an average particle size of about 0.01 to about 10 micrometers and a specific surface area of about 3 to 30 m ⁇ /gm. These inert particulate materials are employed in amounts ranging about 0.3 to about 80%, preferably about 5 to about 50%, based on the weight of the final product. They are especially useful for the polymerization of sticky polymers as disclosed in U.S. Patent Nos. 4,994,534 and 5,304,588.
  • Chain transfer agents, promoters, scavenging agents and other additives can be, and often are, employed in the polymerization process of the invention. Chain transfer agents are often used to control polymer molecular weight. Examples of these compounds are hydrogen and metal alkyls of the general formula M ⁇ R ⁇ g, where M ⁇ is a Group IA, HA or IIIA metal, R ⁇ is an alkyl or aryl, and g is 1, 2, or 3. Preferably, a zinc alkyl is employed; and, of these, diethyl zinc is most preferred.
  • Typical promoters include halogenated hydrocarbons such as CHCI3, CFCI3, CH3CCI3, CF2CICCI3, and ethyl trichloroacetate. Such promoters are well known to those skilled in the art and are disclosed in, for example, U.S. Patent No. 4,988,783.
  • Other organometallic compounds such as scavenging agents for poisons may also be employed to increase catalyst activity. Examples of these compounds include metal alkyls, such as aluminum alkyls, most preferably triisobutylaluminum.
  • Some compounds may be used to neutralize static in the fluidized-bed reactor, others known as drivers rather than antistatic agents, may consistently force the static to from positive to negative or from negative to positive.
  • additives are well within the skill of those skilled in the art. These additives may be added to the reaction zone separately or independently from the liquid catalyst if they are solids, or as part of the catalyst provided they do not interfere with the desired atomization. To be part of the catalyst solution, the additives should be liquids or capable of being dissolved in the catalyst solution.
  • Catalyst Any type of polymerization catalyst may be used in the present process, provided it is stable and sprayable or atomizable when in liquid form. A single unsupported catalyst may be used, or a mixture of unsupported catalysts may be employed if desired.
  • the catalysts are used with appropriate cocatalysts and promoters well known in the art, which cocatalysts and promoters may be introduced into the polymerization zone either together with the catalyst or separately. Examples of suitable catalysts include the following.
  • Ziegler-Natta catalysts including titanium based catalysts such as those described in U.S. Patent Nos. 4,376,062 and 4,379,758.
  • Ziegler-Natta catalysts are well known in the art, and typically are magnesium/titanium/electron donor complexes used in conjunction with an organoaluminum cocatalyst.
  • Chromium based catalysts such as those described in U.S. Patent Nos. 3,709,853; 3,709,954; and 4,077,904.
  • Vanadium based catalysts such as vanadium oxychloride and vanadium acetylacetonate, such as described in U.S. Patent No. 5,317,036.
  • F Cobalt catalysts and mixtures thereof such as those described in U.S. Patent Nos. 4,472,559 and 4,182,814.
  • G Nickel catalysts and mixtures thereof such as those described in U.S. Patent Nos. 4,155,880 and 4,102,817.
  • Rare Earth metal catalysts i.e., those containing a metal having an atomic number in the Periodic Table of 57 to 103, such as compounds of cerium, lanthanum, praseodymium, gadolinium and neodymium. Especially useful are carboxylates, alcoholates, acetylacetonates, halides (including ether and alcohol complexes of neodymium trichloride), and allyl derivatives of such metals.
  • Neodymium compounds particularly neodymium neodecanoate, octanoate, and versatate, are the most preferred rare earth metal catalysts.
  • Rare earth metal catalysts are used to produce polymers of butadiene or isoprene.
  • the practice of this invention is not limited to any particular class or kind of metallocene catalyst, and any unsupported metallocene catalyst useful in slurry, solution, bulk, or gas phase olefin polymerization may be used.
  • One or more than one metallocene catalyst may be employed.
  • at least two metallocene catalysts may be used in a single catalyst composition to achieve a broadened molecular weight distribution polymer product.
  • Metallocene catalysts are organometallic coordination complexes of one or more ⁇ -bonded moieties in association with a metal atom from Groups IIIB to VIII or the rare earth metals of the Periodic Table.
  • Bridged and unbridged mono-, bis-, and tris- cycloalkadienyl/metal compounds are the most common metallocene catalysts, and generally are of the formula: (L) y Rl z (L')MX( x _ y _i) (I)
  • M is a metal from groups IIIB to VIII of the Periodic Table
  • L and L' are the same or different and are ⁇ -bonded ligands coordinated to M, preferably cycloalkadienyl groups such as cyclopentadienyl, indenyl, or fluorenyl groups optionally substituted with one or more hydrocarbyl groups containing 1 to 20 carbon atoms
  • Rl is a C1-C4 substituted or unsubstituted alkylene radical, a dialkyl or diaryl germanium or silicon, or an alkyl or aryl phosphine or amine radical bridging L and L'
  • each X is independently hydrogen, an aryl, alkyl, alkenyl, alkylaryl, or arylalkyl radical having 1-20 carbon atoms, a hydrocarboxy radical having 1-20 carbon atoms, a halogen, R2CO2-, or
  • R22NCO2- wherein each R ⁇ is a hydrocarbyl group containing 1 to about 20 carbon atoms; y is 0, 1, or 2; x is 1, 2, 3, or 4 depending upon the valence state of M; z is 0 or 1 and is 0 when y is 0; and x-y > 1.
  • metallocene catalysts represented by formula I are dialkyl metallocenes such as bis(cyclopentadienyl)titanium dimethyl, bis(cyclopentadienyl)titanium diphenyl, bis(cyclopentadienyl)zirconium dimethyl, bis(cyclopenta- dienyl)zirconium diphenyl, bis(cyclopentadienyl)hafhium methyl and diphenyl, bis(cyclopentadienyl)titanium di-neopentyl, bis(cyclopentadienyl)zirconium di-neopentyl, bis(cyclopentadienyl)titanium dibenzyl, bis(cyclopentadienyl)zirconium dibenzyl, bis(cyclopentadienyl)vanadium dimethyl; mono alkyl metallocenes such as bis(cyclopentadienyl)titanium dimethyl
  • Particularly preferred metallocene catalysts have one of the following formulas (II or III):
  • M is a metal from groups IIIB to VIII, preferably Zr or Hf;
  • L is a substituted or unsubstituted, ⁇ -bonded ligand coordinated to M, preferably a substituted cycloalkadienyl ligand; each Q is independently selected from the group consisting of -O-
  • Y is either C or S, preferably carbon
  • Z is selected from the group consisting of -OR 3 , -NR 3 2, -CR 3 3, - SR 3 , -SiR 3 3, -PR 3 2, and -H, with the proviso that when Q is -NR 3 - then Z is selected from the group consisting of -OR 3 , -NR 3 2, -SR 3 , - SiR 3 3, -PR 3 2, and -H, preferably Z is selected from the group consisting of -OR 3 , -CR 3 3, and -NR 3 2; n is 1 or 2;
  • A is a univalent anionic group when n is 2 or A is a divalent anionic group when n is 1, preferably A is a carbamate, carboxylate or other heteroallyl moiety described by Q, Y and Z combination; and each R 3 is independently a group containing carbon, silicon, nitrogen, oxygen, and/or phosphorus and one or more R 3 groups may be attached to the L substituent, preferably R 3 is a hydrocarbon group containing from 1 to 20 carbon atoms, most preferably an alkyl, cycloalkyl or an aryl group;
  • T is a bridging group selected from the group consisting of alkyl ene or arylene groups containing from 1 to 10 carbon atoms optionally substituted with carbon or heteroatoms, germanium, silicone and alkyl phosphine; and m is 2 to 7, preferably 2 to 6, most preferably 2 or 3.
  • the supportive substituent formed by Q, Y and Z is a unicharged polydentate ligand exerting electronic effects due to its high polarizability, similar to the cyclopentadienyl group.
  • Examples of complexes according to formulas II and III include indenyl zirconium tris(diethylcarbamate), indenyl zirconium tris(trimethylacetate), indenyl zirconium tris(p-toluate), indenyl zirconium tris(benzoate), (l-methylindenyl)zirconium tris(trimethylacetate), (2-methylindenyl) zirconium tris(diethylcarbamate), (methylcyclopentadienyl) zirconium tris(trimethylacetate), cyclopentadienyl tris(trimethylacetate), tetrahydroindenyl zirconium tris(trimethylacetate), and (pentamethyl cyclopentadienyl) zirconium tris(benzoate).
  • Preferred examples are indenyl zirconium tris(diethylcarbamate), indenyl zirconium tris(trimethylacetate), and
  • metallocene catalyst that can be used in accordance with the invention is a constrained geometry catalyst of the formula:
  • M is a metal of Group IIIB to VIII of the Periodic Table of the Elements:
  • Cp is a cyclopentadienyl or substituted cyclopentadienyl group bound in an r bonded mode to M;
  • Z' is a moiety comprising boron, or a member of Group PVB of the Periodic Table of the Elements and optionally sulfur or oxygen, the moiety having up to 20 non-hydrogen atoms, and optionally Cp and Z 1 together form a fused ring system;
  • X' is an anionic ligand group or a neutral Lewis base ligand group having up to 30 non-hydrogen atoms; a is 0, 1, 2, 3 or 4 depending on the valance of M; and
  • Y is an anionic or non-anionic ligand group bonded to Z' and M comprising is nitrogen, phosphorus, oxygen or sulfur having up to 20 non-hydrogen atoms, and optionally Y and Z' together form a fused ring system.
  • Constrained geometry catalysts are well known to those skilled in the art and are disclosed in, for example, U.S. Patent Nos. 5,026,798 and 5,055,438 and published European Application No. 0 416 815 A2.
  • di(imine) metal complexes are transition metal complexes of bidentate ligands selected from the group consisting of:
  • transition metal is selected from the group consisting of Ti, Zr, Sc, V, Cr, a rare earth metal, Fe, Co, ⁇ i, and Pd;
  • R 2 and R 5 are each independently hydrocarbyl or substituted hydrocarbyl, provided that the carbon atom bound to the imino nitrogen atom has at least two carbon atoms bound to it;
  • R 3 and R 4 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or R 3 and R 4 taken together are hydrocarbylene or substituted hydrocarbylene to form a carbocyclic ring;
  • R 44 is hydrocarbyl or substituted hydrocarbyl
  • R 28 is hydrogen, hydrocarbyl or substituted hydrocarbyl or R 44 and R 28 taken together form a ring;
  • R 45 is hydrocarbyl or substituted hydrocarbyl
  • R 29 is hydrogen, substituted hydrocarbyl or hydrocarbyl, or R 45 and R 29 taken together form a ring
  • each R 30 is independently hydrogen, substituted hydrocarbyl or hydrocarbyl, or two of R 30 taken together form a ring
  • each R 31 is independently hydrogen, hydrocarbyl or substituted hydrocarbyl
  • R 46 and R 47 are each independently hydrocarbyl or substituted hydrocarbyl, provided that the carbon atom bound to the imino nitrogen atom has at least two carbon atoms bound to it;
  • R 48 and R 49 are each independently hydrogen, hydrocarbyl, or substituted hydrocarbyl
  • R 20 and R 23 are independently hydrocarbyl or substituted hydrocarbyl
  • R 21 and R 22 are independently hydrogen, hydrocarbyl or substituted hydrocarbyl; and n is 2 or 3; and provided that: said transition metal also has bonded to it a ligand that may be displaced by or added to the olefin monomer being polymerized; and when the transition metal is Pd, said bidentate ligand is (V), (VII) or (VIII).
  • Activating cocatalysts suitable for use with metallocene catalysts include the following: (a) branched or cyclic oligomeric poly(hydrocarbyl-aluminum oxide)s which contain repeating units of the general formula -(Al(R*)O)-, where R* is hydrogen, an alkyl radical containing from 1 to about 12 carbon atoms, or an aryl radical such as a substituted or unsubstituted phenyl or naphthyl group; (b) ionic salts of the general formula [A+] [BR 4 — ] , where A + is a cationic Lewis or Bronsted acid capable of abstracting an alkyl, halogen, or hydrogen from the metallocene catalysts, B is boron, and R is a substituted aromatic hydrocarbon, preferably a perfluorophenyl radical; and (c) boron alkyls of the general formula BR 3, where R is as defined above.
  • the activating cocatalyst is an aluminoxane such as methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), or a boron alkyl.
  • Aluminoxanes are preferred and their method of preparation is well known in the art.
  • Aluminoxanes may be in the form of oligomeric linear alkyl aluminoxanes represented by the formula:
  • R*** is methyl
  • MMAO a mixture of methyl and C2 to C12 alkyl groups wherein methyl comprises about 20 to 80 percent by weight of the R*** group.
  • the mole ratio of activating cocatalyst to metallocene catalyst usefully employed can vary over a wide range.
  • the cocatalyst is a branched or cyclic oligomeric poly(hydrocarbylaluminum oxide)
  • the mole ratio of aluminum atoms contained in the poly(hydrocarbylaluminum oxide) to metal atoms contained in the metallocene catalyst is generally in the range of from about 2:1 to about 100,000:1, preferably in the range of from about 10:1 to about 10,000:1, and most preferably in the range of from about 50:1 to about 2,000:1.
  • the cocatalyst is an ionic salt of the formula
  • the mole ratio of boron atoms contained in the ionic salt or the boron alkyl to metal atoms contained in the metallocene catalyst is generally in the range of from about 0.5:1 to about 10:1, preferably in the range of from about 1:1 to about 5:1.
  • the unsupported catalyst is introduced into the polymerization reactor in the form of liquid droplets.
  • the liquid droplets comprise a solution, dispersion, or emulsion of one or more catalysts, optionally one or more cocatalysts, and optionally promoters or other catalyst additives in one or more liquid solvents.
  • the liquid droplets comprise a solution or emulsion of a catalyst and a cocatalyst. More preferably, the liquid droplets comprise a solution of a catalyst and a cocatalyst.
  • the catalyst is typically dissolved or prepared in a solvent.
  • the cocatalyst is also prepared and handled in a solvent, which may be the same or different than that used for the catalyst.
  • These two solutions can be combined after being fed into the reactor, or preferably before they are fed into the reactor.
  • the feed rate of the two solutions can be varied to adjust the mole ratio of cocatalyst to catalyst in the mixture, in order to change resin properties or to minimize the total cost of cocatalyst and catalyst.
  • Solvents that can be utilized to form solutions of the unsupported catalyst and/or cocatalyst are inert solvents, preferably non-functional hydrocarbon solvents, and may include aliphatic hydrocarbons such as butane, isobutane, ethane, propane, pentane, isopentane, hexane, heptane, octane, decane, dodecane, hexadecane, octadecane, and the like; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, cyclooctane, norbornane, ethylcyclohexane and the like; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, propylbenzene, butylbenzene, xylene, tetrahydrofuran and the like; and petroleum fractions such as
  • halogenated hydrocarbons such as methylene chloride, chlorobenzene, and the like may also be utilized.
  • inert is meant that the material being referred to is non- deactivating in the polymerization zone under the conditions of gas phase, polymerization and does not deactivate the catalyst in or out of the polymerization zone.
  • non-functional is meant that the solvents do not contain groups such as strong polar groups which can deactivate the active catalyst metal sites.
  • Any atomization device can be used to introduce the liquid droplets into the reactor.
  • the liquid droplet size and catalyst concentration in the liquid droplets can be varied independently.
  • the flow rate of solvent can be adjusted so that only the catalyst concentration and number of liquid droplets are changed.
  • Suitable nozzles include air- assisted or air-blast atomizers, pressure atomizers, rotary atomizers, ultrasonic, effervescent, and electrostatic nozzles. Particularly preferred nozzles are those described in copending U.S.
  • Nozzles can produce either a narrow or wide liquid droplet size distribution. A narrow distribution is preferred, but a wide distribution can be tolerated. Nozzles that produce larger liquid droplets may require higher amounts of liquid to provide the desired amount of catalyst per liquid droplet.
  • the average particle size of the polyolefin produced in the presence of the unsupported catalyst is controlled by adjusting the size of the liquid droplets containing catalyst, or the concentration of catalyst in the liquid droplets, or both. If both the size of the liquid droplets and the catalyst concentration in the liquid droplets are adjusted, they may be adjusted simultaneously or in sequence.
  • the nature of both the catalyst and the activating cocatalyst determine the magnitude and direction in which the size of the liquid droplets and the catalyst concentration in the liquid droplets should be adjusted in order to achieve a given average polyolefin product particle size.
  • the average particle size of the ethylene copolymer may be increased or decreased by about 10 % by adjusting the size of the liquid droplets by about 10 % or adjusting the catalyst concentration in the liquid droplets (i.e., in the total liquid feedstream of unsupported catalyst, cocatalyst, solvent(s), etc.) by about 33 %.
  • the average particle size of an ethylene copolymer so made may be increased or decreased by about 20% by adjusting the size of the liquid droplets by about 20 % or adjusting the catalyst concentration by about 40 %.
  • a 10 % increase in liquid droplet size can lead to a 50% or more increase in ethylene copolymer average particle size.
  • diluting the catalyst in the liquid feedstream by 33% can decrease the ethylene copolymer average particle size by 50% or more.
  • the average diameter of the liquid droplets is generally in the range of about 0.1 to about 1000 micrometers, preferably 1 to 300 micrometers, most preferably about 10 to 75 micrometers.
  • the size, i.e., average diameter, of the liquid droplets may be adjusted in one of several ways.
  • the flow rate of the liquid feedstream of unsupported catalyst, cocatalyst, solvent(s), etc. may be increased in order to increase the size of the liquid droplets, or decreased to decrease the size of the liquid droplets.
  • the flow rate of the inert carrier gas into the polymerization reactor may be increased to break up the liquid into smaller sized droplets, which in turn decreases the average particle size of the polyolefin produced.
  • the flow rate of the inert carrier gas may be decreased, allowing the size of the liquid droplets to increase, thereby increasing the average particle size of the polyolefin produced. This is a preferred method of adjusting the liquid droplet size, and thereby polyolefin average particle size.
  • the size of the liquid droplets containing the catalyst is adjusted while using an effervescent spray nozzle, such as that described in copending U.S. Application
  • Droplet Size with an Effervescent Spray Nozzle of Williams et al. (docket no. 17733) to spray the liquid feedstream containing the unsupported catalyst into the polymerization reactor.
  • a stream of liquid or gas is passed through an inner tube, while a liquid or gas is passed cocurrently through an annular space defined by the inner tube and a concentric outer tube.
  • the direction of flow of the liquid and gas is generally along the central axis of the tubes.
  • the liquid feedstream containing the unsupported catalyst and atomization gas are fed through their respective inlets and exit through a common orifice at the spray tip.
  • the size of the liquid droplets containing the catalyst is adjusted while using a perpendicular spray nozzle such as that described in copending U.S.
  • Such a perpendicular nozzle comprises a tube for delivering the liquid feedstream containing the unsupported catalyst wherein there is an inlet end for the input of the liquid, and optionally, a gas.
  • distal end The other end of the tube (i.e., "distal end") wherein there is at least one exit hole (orifice) which is at least 10-20°, preferably more than 45°, and most preferably 60 to 90°, off from the direction of flow of the liquid within the nozzle (i.e., from the central axis of the tube), where the orifice is located towards the distal end of the nozzle.
  • Said nozzle may have any number of orifices and may include a gas stream within the liquid feedstream. There is no need for a separate mixing chamber for the gas and liquid within the nozzle.
  • the distal end of the nozzle may be of any geometric configuration, e.g., bulbous, rounded, parabolic, conical, or semicircular, but to limit turbulence the nozzle preferably is tapered at about 5 to 15 degrees off horizontal (the central axis of the tube). Higher taper angles can be tolerated given that the taper from horizontal is gradual. A tapered tip also minimizes fouling because of the small area available for accumulation of catalyst and polymer.
  • the liquid feedstream may be atomized with an inert carrier gas, as is done with a gas-assisted perpendicular spray nozzle.
  • a perpendicular pressure nozzle could be used to deliver a perpendicular spray of high-pressure liquid in the absence of an atomizing gas.
  • the perpendicular feeding geometry can be used with effervescent gas- liquid contact in the spraying nozzle or with an ultrasonic nozzle, or could also be applied to other known atomization devices, such as electrostatic, sonic-whistle, or rotary, etc. nozzles.
  • the concentration of catalyst in the liquid droplets is in the range of about 0.01 to about 10,000 millimoles/liter, preferably 0.1 to about 1000 millimoles/liter, more preferably 1 to about 100 millimoles/liter.
  • the concentration of catalyst in the liquid droplets can be adjusted within this range by changing the amount of solvent fed with the catalyst to the polymerization zone. It should be borne in mind, however, that if too much solvent is added, the reactor dew point is increased and the catalyst activity per volume of droplet is low. These factors slow the evaporation rate from the droplets so that the overall average polymer particle size may be too large. With a high activity catalyst, a low dew point solvent, and a concentrated catalyst solution, the polymer particles can overheat and fuse together. Depending on the type of agglomeration occurring, a change in the amount of solvent fed with the catalyst can shift the average polyolefin particle size into a desirable range. The opposite can also occur, that is, changes in catalyst dilution can improve a very small average particle size to an acceptable range.
  • a gas phase polymerization reactor may be cycled through dozens of products, requiring different reactor process conditions and different catalysts.
  • concentration of catalyst and cocatalyst as mixed may not be suitable for some of the required products or reactor conditions.
  • the mixture of catalyst and cocatalyst can be diluted further with one or more additional solvents, referred to as diluents. These diluents may be the same as the solvent(s) originally used for the catalyst and cocatalyst, or may be completely different.
  • the actual concentration of catalyst and cocatalyst in the liquid droplets can then be varied over a wide range of conditions, obviating the need for catalyst and cocatalyst solutions of varying concentrations.
  • the feedrates of catalyst and cocatalyst are adjusted to maintain the target production rates, the optimum catalyst/cocatalyst economics, and the desired resin properties.
  • the amount of solvent and diluent added to the catalyst and cocatalyst can be changed without affecting the production rate. This allows for droplet size control while maintaining a stable process.
  • the use of two or more solvents or diluents having different evaporation rates has the additional advantage of allowing one to control better the rate of solvent evaporation from the liquid droplets. This can be used to moderate the tendency of the droplets either to overheat or to wet and adhere.
  • the diluent can be combined directly with and introduced into the polymerization reactor with the liquid feedstream of catalyst, cocatalyst, and solvent(s).
  • the diluent can be fed to the polymerization reactor separately from the liquid feedstream of catalyst, cocatalyst, and solvent(s), for example as an induced condensing agent.
  • diluent can be both added to the liquid feedstream of catalyst, cocatalyst, and solvent(s) and fed separately to the reactor.
  • the relative rate of solvent evaporation from the liquid droplets can be controlled by adjusting the amount of diluent vapor in the cycle gas.
  • the evaporation rate of solvent in the liquid droplets decreases, which leads to increased polyolefin particle size under some conditions.
  • the amount of solvent in the liquid droplets can then be decreased by, for example, feeding less solvent with the catalyst, and the liquid droplet size can be decreased by feeding more inert carrier gas with the unsupported catalyst.
  • the liquid droplets can form new, stable polymer particles more readily under the conditions of increased dew point or condensation in the cycle gas.
  • the average particle size of a polyolefin produced using an unsupported catalyst in a gas phase, fluidized bed polymerization reactor is controlled by adjusting at least one of: a) the size of the liquid droplets containing the catalyst introduced into the polymerization reactor, and b) the concentration of catalyst composition in the liquid droplets, while introducing said liquid droplets into a particle lean zone in the reactor in the manner described in copending U.S. Application Serial No. 08/659,764 filed June 6, 1996.
  • a particle lean zone can be established in the reactor by feeding the unsupported catalyst in any manner such that the liquid droplets containing the catalyst do not immediately contact a substantial portion of the resin particles of the fluidized bed.
  • the particle density in the particle lean zone is at least 10 times lower than that in the fluidized bed.
  • the time between a liquid droplet being introduced into the reactor and its contacting the particles in the bed ranges from about 0.01 seconds to 60 seconds, preferably about 0.01 to 30 seconds, and most preferably about 0.01 seconds to 5 seconds.
  • a particle lean zone may be a section of the reactor that normally does not contain the fluidized bed, such as the disengaging section, the gas recirculation system, or the area below the distributor plate.
  • the particle lean zone may also be created by deflecting resin away from the unsupported catalyst spray with a stream of gas.
  • the liquid feedstream containing unsupported catalyst, accompanied by an inert carrier gas is surrounded by at least one other gas which serves to move or deflect resin particles of the bed out of the path of the liquid droplets of unsupported catalyst as they enter the fluidization zone and away from the area of catalyst entry, thereby providing a particle lean zone.
  • the unsupported catalyst in the carrier gas is surrounded by at least two other gases, the first gas serving primarily to deflect resin particles of the bed out of the path of the liquid droplets and the second gas primarily to prevent the injection tube or nozzle tip from becoming clogged.
  • the average particle size of the polyolefin produced ranges from about 0.01 to 0.06, preferably about 0.015 to 0.04, most preferably about 0.02 to 0.03 inches.
  • low particle size can result in high fines levels, which present handling difficulties due to possible dust-cloud formation and explosion.
  • small particles can more readily be entrained from the fluidized bed, leading to fouling in the cycle gas piping and equipment, such as the cooler or distributor plate.
  • Small particles are also more susceptible to electrostatic forces, leading to sheeting or wall fouling.
  • Large average particle size on the other hand, can often lead to bed segregation and other fluidization problems, as well as a decrease in the resin bulk density.
  • Control of polyolefin average particle size according to the invention can improve reactor operability by avoiding these problems.
  • the average particle size of the polyolefin produced can be increased to reduce the possibility of reactor sheeting or other ill effects of static, perhaps to a 0.04 to 0.06 inch range.
  • the static risk decreases the particle size can be adjusted back to a middle range.
  • the average particle size of the polyolefin can also be increased when producing products that tend to foul the cycle gas line. Fewer particles are entrained and fouling is reduced.
  • the amount of offgrade polyolefin produced is proportional to the bed weight of polymer in the reactor.
  • the average particle size of the polyolefin Prior to a transition, the average particle size of the polyolefin can be increased, causing the bulk density to decrease.
  • the bed weight concomitantly decreases to compensate for the reduced bulk density. This requires fewer pounds of transition grade resin to be made.
  • the increased average particle size also facilitates low bed level transitions so that offgrade production can be decreased.
  • the catalyst used for Examples 1 through 4 was a Zr-based metallocene at a 2 wt % solution in n-hexane.
  • the solution was used as made for Examples 1 and 2, but was diluted with 1-hexene for Examples 3 and 4 to 1.33 wt-% catalyst with 32.9% 1-hexene and 65.8% hexane.
  • Catalyst was mixed in line with MMAO 3A (modified methyl alumoxane) as received from Akzo Nobel at 7.1 wt % Al. Additional dilution was performed by adding isopentane to the mixture before introducing it to the reactor. Catalyst and MMAO feedrates were adjusted to provide a final Al:Zr molar ratio between 330 and 340.
  • the reactor was 2.4 m in diameter and was operated with a bed height of 11.6 m and a superficial gas velocity of approximately 0.6 m/s. Total reactor pressure was 1960 kPa. ATMER-163, marketed by ICI, was added as necessary to the reactor to control the buildup of electrostatic charge.
  • the catalyst atomization devices used in all examples were located at the end of a 1/4" (0.635 cm) OD stainless steel tube, and they could be removed from the reactor during operation.
  • This tube passed through a 3/4-inch (1.9 cm) schedule-40 pipe.
  • a stream of 1000 to 1180 kg/hr of ethylene monomer at a temperature between 85 and 95°C was fed through the annular space between the ⁇ -inch tube and the 3/4- inch pipe.
  • This monomer stream is referred to as a nozzle cleaning gas.
  • the 3/4-inch pipe was located in the center of a six-inch pipe (15.2 cm), through which was fed between 22,700 and 29,500 kg/hr of cycle gas, known as particle deflecting gas.
  • the six-inch pipe extended 53 cm into the reactor, the 3/4-inch pipe extended 61 cm into the reactor, and the spray nozzle extended 66 cm into the reactor, at a location 2.4 m above the distributor plate.
  • EXAMPLES 1 and 2 A seed bed was charged to the reactor and it was dried to 9 ppm water. It was pressurized to 790 kPa of nitrogen and then 22.7 kg/hr of 10 wt % TEAL in isopentane were fed to the reactor and allowed to circulate for 1 hour. The conditions listed in the Table below were established in the reactor. Catalyst was fed through a perpendicular spray nozzle, located within the stream of 22,700 kg/hr of cycle gas, as described above. Catalyst and MMAO were mixed for 15 to 30 seconds. The reactor was started with a nitrogen carrier rate of 27.2 kg/hr. This caused the APS of the resin to drop rapidly from 0.66 to 0.356. cm, which was not acceptable for good operation. The nitrogen carrier rate was then decreased to 14.3 lbs/hr and the APS increased to 0.533 cm, where it remained stable, and desirable.
  • the APS can be controlled. In other cases, if the APS is too large, the carrier gas rate can be increased to lower the APS back to an acceptable range.
  • APS can also be controlled by adjusting the amount of diluent added to the catalyst and cocatalyst mixture.
  • the reactor was operating with the perpendicular spray nozzle and with the 1.33 wt % catalyst in the mixed hexane/hexene solvent, which was mixed with the MMAO for 19 minutes before being diluted with isopentane and fed to the reactor.
  • Several hundred pounds per hour of isopentane were additionally fed to the reactor at a separate location to induce condensing mode operation.
  • the amount of isopentane in the cycle gas was increased to about 5 mole percent.
  • Example 3 The reactor was operated with the conditions listed in Example 3, and the APS was stable at 0.483 mm.
  • the isopentane feedrate then was decreased for Example 4, as shown in the Table, and the APS increased to 0.610 mm, demonstrating that the APS can be controlled while in condensing mode, and that it can be controlled with the amount of isopentane diluent added to the catalyst mixture. It also was demonstrated throughout the course of a 10 day run with the perpendicular spray nozzle that the APS could be kept in a narrow range by adjusting the nitrogen and isopentane carrier rates independently, or in concert.

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  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Organic Chemistry (AREA)
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Abstract

Procédé servant à commander la dimension moyenne des particules d'une polyoléfine produite au moyen du contact, dans des conditions de polymérisation en phase gazeuse, d'au moins un monomère avec des gouttelettes de liquide contenant un catalyseur non supporté, ce qui consiste à régler au moins un de (a) la dimension des gouttelettes de liquide et (b) de la concentration du catalyseur dans les gouttelettes de liquide.
PCT/US1998/003329 1997-02-19 1998-02-18 Production de polyolefines dont les particules presentent une dimension commandee WO1998037103A1 (fr)

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US08/802,232 1997-02-19

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000039175A1 (fr) * 1998-12-30 2000-07-06 Union Carbide Chemicals & Plastics Technology Corporation Procede de reduction du colmatage de tubes grace a l'utilisation de catalyseurs non supportes pre-actives
EP1057523A1 (fr) * 1999-06-04 2000-12-06 Union Carbide Chemicals & Plastics Technology Corporation Alimentation du catalyseur par buse à ultrasons pour polymérisation d'olefines dans un lit fluidisé
US7341971B2 (en) 2001-12-19 2008-03-11 Borealis Technology Oy Production of olefin polymerization catalysts
KR101057854B1 (ko) * 2007-01-22 2011-08-19 주식회사 엘지화학 폴리올레핀의 입도 조절 방법
WO2016102513A1 (fr) * 2014-12-22 2016-06-30 Norner Verdandi As Polyéthylène pour tuyaux

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0593083A1 (fr) * 1992-10-16 1994-04-20 Union Carbide Chemicals & Plastics Technology Corporation Réaction de polymérisation en phase gazeuse utilisant des catolyseurs non supportés, solubles

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0593083A1 (fr) * 1992-10-16 1994-04-20 Union Carbide Chemicals & Plastics Technology Corporation Réaction de polymérisation en phase gazeuse utilisant des catolyseurs non supportés, solubles

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000039175A1 (fr) * 1998-12-30 2000-07-06 Union Carbide Chemicals & Plastics Technology Corporation Procede de reduction du colmatage de tubes grace a l'utilisation de catalyseurs non supportes pre-actives
EP1057523A1 (fr) * 1999-06-04 2000-12-06 Union Carbide Chemicals & Plastics Technology Corporation Alimentation du catalyseur par buse à ultrasons pour polymérisation d'olefines dans un lit fluidisé
US6365695B1 (en) 1999-06-04 2002-04-02 Union Carbide Chemicals & Plastics Technology Corporation Ultrasonic catalyst feed for fluid bed olefin polymerization
AU768842B2 (en) * 1999-06-04 2004-01-08 Union Carbide Chemicals & Plastics Technology Corporation Ultrasonic catalyst feed for fluid bed olefin polymerization
US7341971B2 (en) 2001-12-19 2008-03-11 Borealis Technology Oy Production of olefin polymerization catalysts
US7718563B2 (en) 2001-12-19 2010-05-18 Borealis Technology Oy Production of olefin polymerization catalysts
KR101057854B1 (ko) * 2007-01-22 2011-08-19 주식회사 엘지화학 폴리올레핀의 입도 조절 방법
WO2016102513A1 (fr) * 2014-12-22 2016-06-30 Norner Verdandi As Polyéthylène pour tuyaux
JP2018501394A (ja) * 2014-12-22 2018-01-18 ノルナー・ヴェルダンディ・アーエス パイプ用ポリエチレン
RU2694769C2 (ru) * 2014-12-22 2019-07-16 Норнер Верданди Ас Полиэтилен для труб
US10604603B2 (en) 2014-12-22 2020-03-31 Norner Verdandi As Polyethylene for pipes
US10995169B2 (en) 2014-12-22 2021-05-04 Norner Verdandi As Polyethylene for pipes

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ID19921A (id) 1998-08-20
AU6178798A (en) 1998-09-09

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