WO2010080871A1 - Additive for gas phase polymerization processes - Google Patents

Additive for gas phase polymerization processes Download PDF

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Publication number
WO2010080871A1
WO2010080871A1 PCT/US2010/020313 US2010020313W WO2010080871A1 WO 2010080871 A1 WO2010080871 A1 WO 2010080871A1 US 2010020313 W US2010020313 W US 2010020313W WO 2010080871 A1 WO2010080871 A1 WO 2010080871A1
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reactor
catalyst
polysulfone
polymerization
static
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PCT/US2010/020313
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French (fr)
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F. David Hussein
Michael E. Muhle
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Univation Technologies, Llc
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Priority to US20461609P priority Critical
Priority to US61/204,616 priority
Application filed by Univation Technologies, Llc filed Critical Univation Technologies, Llc
Publication of WO2010080871A1 publication Critical patent/WO2010080871A1/en

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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F10/00Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F210/00Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/16Copolymers of ethene with alpha-alkenes, e.g. EP rubbers

Abstract

A polymerization process including: polymerizing at least one olefin to form an olefin based polymer in a gas phase polymerization reactor; and feeding at least one polysulfone additive system to the polymerization reactor, wherein the polysulfone additive system includes a polysulfone copolymer, a polymeric polyamine, and an oil-soluble sulfonic acid.

Description

ADDITIVE FOR GAS PHASE POLYMERIZATION PROCESSES

CROSS REFERENCE TO RELATED CASE [0001] This application claims the benefit of U.S. provisional application Serial No. 61/204,616, filed January 8, 2009, the disclosure of which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] Embodiments disclosed herein relate generally to the use of additives in polymerization processes. More specifically, embodiments disclosed herein relate to the use of additive systems comprising a polysulfone copolymer, a polymeric polyamine, and an oil-soluble sulfonic acid. The additive systems are suitable for use in the manufacture of ethylene-based and propylene- based polymers for food contact applications.

BACKGROUND

[0003] Metallocene catalysts allow the production of polyolefins with unique properties such as narrow molecular weight distribution. These properties in turn result in improved structural performance in products made with the polymers, such as greater impact strength and clarity in films. While metallocene catalysts have yielded polymers with improved characteristics, they have presented new challenges when used in traditional polymerization systems. [0004] For example, when metallocene catalysts are used in fluidized bed reactors, "sheeting" and the related phenomena "drooling" may occur. See U.S. Patent Nos. 5,436,304 and 5,405,922. "Sheeting" is the adherence of fused catalyst and resin particles to the walls of the reactor. "Drooling" or dome sheeting occurs when sheets of molten polymer form on the reactor walls, usually in the expanded section or "dome" of the reactor, and flow along the walls of the reactor and accumulate at the base of the reactor. Dome sheets are typically formed much higher in the reactor, on the conical section of the dome, or on the hemi-spherical head on the top of the reactor.

[0005] Sheeting and drooling may be a problem in commercial gas phase polyolefin production reactors if the risk is not properly mitigated. The problem is characterized by the formation of large, solid masses of polymer on the walls of the reactor. These solid masses or polymer (the sheets) may eventually become dislodged from the walls and fall into the reaction section, where they may interfere with fluidization, block the product discharge port, and usually force a reactor shut-down for cleaning.

[0006] Various methods for controlling sheeting have been developed. These often involve monitoring the static charges near the reactor wall in regions where sheeting is known to develop and introducing a static control agent into the reactor when the static levels fall outside a predetermined range. For example, U.S. Patent Nos. 4,803,251 and 5,391,657 disclose the use of various chemical additives in a fluidized bed reactor to control static charges in the reactor. A positive charge generating additive is used if the static charge is negative, and a negative charge generating additive is used if the static charge is positive.

[0007] U.S. Patent Nos. 4,803,251 and 5,391,657 disclose that static plays an important role in the sheeting process with Ziegler-Natta catalysts. When the static charge levels on the catalyst and resin particles exceed certain critical levels, the particles become attached by electrostatic forces to the grounded metal walls of the reactor. If allowed to reside long enough on the wall under a reactive environment, excess temperatures can result in particle sintering and melting, thus producing the sheets or drools.

[0008] U.S. Patent No. 4,532,311 discloses the use of a reactor static probe (the voltage probe) to obtain an indication of the degree of electrification of the fluid bed. U.S. Patent No. 4,855,370 combined the static probe with addition of water to the reactor (in the amount of 1 to 10 ppm of the ethylene feed) to control the level of static in the reactor. This process has proven effective for Ziegler-Natta catalysts, but has not been effective for metallocene catalysts. [0009] For conventional catalyst systems such as traditional Ziegler-Natta catalysts or chromium-based catalysts, sheet formation usually occurs in the lower part of the fluidized bed. Formation of dome sheets rarely occurs with Ziegler-Natta catalysts. For this reason, the static probes or voltage indicators have traditionally been placed in the lower part on the reactor. For example, in U.S. Patent No. 5,391,657, the voltage indicator was placed near the reactor distributor plate. See also U.S. Patent No. 4,855,370. The indicators were also placed close to the reactor wall, normally less than 2 cm from the wall.

[0010] U.S. Patent No. 6,548,610 describes a method of preventing dome sheeting (or "drooling") by measuring the static charge with a Faraday drum and feeding static control agents to the reactor as required to maintain the measured charge within a predetermined range. Conventional static probes are described in U.S. Patent Nos. 6,008,662, 5,648,581, and 4,532,311. Other background references include WO 99/61485, WO 2005/068507, EP 0 811 638 A, EP 1 106 629 A, and U.S. Patent Application Publication Nos. 2002/103072 and 2008/027185.

[0011] As a result of the risks associated with reactor discontinuity problems when using metallocene catalysts, various techniques have been developed that are said to result in improved operability. For example, various supporting procedures or methods for producing a metallocene catalyst system with reduced tendencies for fouling and better operability have been discussed in U.S. Patent No. 5,283,278, which discloses the prepolymerization of a metallocene catalyst. Other supporting methods are disclosed in U.S. Patent Nos. 5,332,706 and 5,473,028 5,427,991, 5,643,847 5,492,975, 5,661,095, and PCT publications WO 97/06186, WO 97/15602, and WO 97/27224.

[0012] Others have discussed different process modifications for improving reactor continuity with metallocene catalysts and conventional Ziegler-Natta catalysts. See, PCT publications WO 96/08520, WO 97/14721, U.S. Patent Nos. 5,627,243, 5,461,123, 5,066,736, 5,610,244, 5,126,414 and EP-Al 0 549 252. There are various other known methods for improving operability including coating the polymerization equipment, controlling the polymerization rate, particularly on start-up, and reconfiguring the reactor design and injecting various agents into the reactor.

[0013] With respect to injecting various agents into the reactor, antistatic agents and process "continuity additives" have been the subject of various publications. For example, EP 0 453116 discloses the introduction of antistatic agents to the reactor for reducing the amount of sheets and agglomerates. U.S. Patent No. 4,012,574 discloses adding a surface-active compound having a perfluorocarbon group to the reactor to reduce fouling. WO 96/11961, discloses an antistatic agent for reducing fouling and sheeting in a gas, slurry or liquid pool polymerization process as a component of a supported catalyst system. U.S. Patent Nos. 5,034,480 and 5,034,481 disclose a reaction product of a conventional Ziegler-Natta titanium catalyst with an antistatic agent to produce ultrahigh molecular weight ethylene polymers. For example, WO 97/46599 discloses the use of soluble metallocene catalysts in a gas phase process utilizing soluble metallocene catalysts that are fed into a lean zone in a polymerization reactor to produce stereoregular polymers. WO 97/46599 also discloses that the catalyst feedstream can contain antifoulants or antistatic agents such as ATMER 163 (commercially available from ICI Specialty Chemicals, Baltimore, Md.). Many of these references refer to anti-static agents but in most cases the static is never totally eliminated. Rather it is reduced to an acceptable level by generating a charge opposite that which currently exists in the polymerization system. In this sense, these "anti-static" agents are really "pro-static" agents that generate a countervailing charge that reduces the net static charge in the reactor. Herein we will refer to these compounds as static control agents.

[0014] Several of the above-mentioned references disclose the use of static control agents that, when introduced into a fluidized bed reactor, may influence or drive the static charge in the fluidized bed in a desired direction. Depending upon the static control agent used, the resulting static charge in the fluidized bed may be negative, positive, or a neutral charge. Static control agents, for example, may include positive charge generating species such as MgO, ZnO, CuO, alcohols, oxygen, nitric oxide, and negative charge generating species such as V2O5, Siθ2, Tiθ2, Fe2θ3, water, and ketones. Other static control agents are also disclosed in EP 0229368 and U.S. Patent Nos. 5,283,278, 4,803,251, and 4,555,370, among others. As described in U.S. Patent Application Publication No. 2008/027185, aluminum stearate, aluminum distearate, ethoxylated amines, OCTASTAT 2000, a mixture of a polysulfone copolymer, polymeric polyamine, and oil-soluble sulfonic acid, as well as mixtures of carboxylated metal salts with amine-containing compounds, such as those sold under the trade names KEMAMINE and ATMER, may also be used to control static levels in a reactor. Various other static control agents are disclosed in U.S. Patent Application Publication No. 20050148742. [0015] U.S. Patent No. 5,026,795, discloses the addition of an antistatic agent with a liquid carrier to the polymerization zone in a gas phase polymerization reactor. Preferably, the antistatic agent is mixed with a diluent and introduced into the reactor by a carrier comprising the comonomer. The preferred antistatic agent disclosed is a mixture, which was marketed under the trademark STADIS 450 by Octel Starreon (currently available as OCTASTAT 3000 from Innospec Inc.) and which contains a polysulfone, a polymeric polyamine, a sulfonic acid, and toluene. The amount of antistatic agent is disclosed to be very important. Specifically, there must be sufficient antistatic agent to avoid adhesion of the polymer to the reactor walls, but not so much that the catalyst is poisoned. U.S. Patent No. 5,026,795 also discloses that the amount of the preferred antistatic agent is in the range of about 0.2 to 5 parts per million by weight (ppmw) of polymer produced; however, no method for optimizing the level of antistatic agent is disclosed based on measurable reactor conditions. Various other references discussing use of OCTASTAT 2000, OCTASTAT 2500, and OCTASTAT 3000 (STADIS 425 and STADIS 450) may include U.S. Patent Nos. 7,205,363, 6,646,074, 6,894,127, 6,857,322, 6,639,028, 6,562,924, 6,518,385, 6,462,161, 6,998,440, 5,283,278, and 5,414,064, U.S. Patent Application Publication No. 2008/0161510, and PCT Publication Nos. WO2007/131646, WO2007/131645, and WO2007/137396.

[0016] Static control agents, including several of those described above, may result in reduced catalyst productivity. The reduced productivity may be as a result of residual moisture in the additive. Additionally, reduced productivity may result from interaction of the polymerization catalyst with the static control agent, such as reaction or complexation with hydroxyl groups in the static control agent compounds. Depending upon the static control agent used and the required amount of the static control agent to limit sheeting, loss in catalyst activities of 40% or more have been observed. [0017] Additionally, continuity additives as formulated and as available, may include various components used as solvents or as residual components from production. For example, OCTASTAT 3000 (formerly STADIS 450) includes a polysulfone, a polymeric polyamine, a sulfonic acid, in a solvent / carrier fluid including toluene, light alcohols such as isopropanol and methanol, naphtha, and naphthalene. Such an admixture, however, does not meet regulatory approval for use in products that come into contact with food.

[0018] Changes in continuity additive formulation to meet food-grade regulatory requirements are possible, such as by changing solvents and carrier fluids. It cannot be predicted, however, if and how changes to the continuity additive formulation will affect various polymerization processes and catalysts. For example, although "active" ingredients in continuity additive formulations may remain similar, replacement of some compounds, including toluene and alcohols, which themselves may have a charge characteristic (antistatic effect), may result in an unpredictable change in how the continuity additive formulation impacts reactor performance. Changes in solvents and carrier fluids, for example, may inadvertently change the interaction of the continuity additive system, as a whole, with reactor components (metals and coatings) and with the polymers produced. With regard to fluidized bed gas-phase reactor performance, changing solvents and carrier fluids may additionally result in unpredictable changes to reactor operations, such as when operating in the condensed mode.

[0019] Further, it cannot be predicted how changes in the continuity additive formulation may result in increased interaction with various catalysts due to the presence of new compounds in the formulation or the absence of previously used compounds. For example, changing various compounds may unpredictably affect catalyst activity, productivity, and performance, especially for specialty catalysts, such as bimetallic catalysts.

[0020] Accordingly, there exists a need for additives suitable for contact with food and useful, for example, for the control of static levels, and thus sheeting, in a fluidized bed reactor, especially for use with, for example, bimetallic catalyst systems and for use in, for example, gas- phase polymerization processes operating in a condensed mode.

SUMMARY

[0021] Disclosed herein is a polymerization process that includes: polymerizing at least one olefin to form an olefin based polymer in a gas phase polymerization reactor and feeding at least one polysulfone additive system to the polymerization reactor, wherein the polysulfone additive system includes: a polysulfone copolymer; a polymeric polyamine; an oil-soluble sulfonic acid; and a carrier fluid including at least one of pentane, hexane, heptane, and a food grade oil. The gas phase polymerization reactor may be operating in a condensed mode. The process may further comprise feeding a bimetallic catalyst to the polymerization reactor. [0022] Also disclosed herein is a process for copolymerizing ethylene and one or more alpha olefins in a gas phase reactor, including: combining ethylene and one or more of 1-butene, 1- hexene, or 1-octene in the presence of a bimetallic catalyst comprising at least one metallocene, an activator and a support; monitoring static in said reactor by at least one recycle line static probe, at least one upper bed static probe, at least one annular disk static probe, or at least one distributor plate static probe; maintaining the static at a desired level by use of at least one polysulfone additive system including: a polysulfone copolymer; a polymeric polyamine; an oil- soluble sulfonic acid; and at least one of pentane, hexane, heptane, and a food grade oil, the polysulfone additive system being present in said reactor in the range from about 0.1 to about 50 ppm, based on the weight of polymer produced by said combining.

DETAILED DESCRIPTION

[0023] Before the present compounds, components, compositions, and/or methods are disclosed and described, it is to be understood that unless otherwise indicated this invention is not limited to specific compounds, components, compositions, reactants, reaction conditions, ligands, metallocene structures, or the like, as such may vary, unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0024] It must also be noted that, as used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless otherwise specified. [0025] Embodiments disclosed herein relate generally to use of polysulfone additive systems in polymerization processes, such as those for the production of ethylene-based and propylene- based polymers. More specifically, embodiments disclosed herein relate to the use of polysulfone additive systems comprising a polysulfone copolymer, a polymeric polyamine, and oil-soluble sulfonic acid suitable for use in the manufacture of ethylene-based and propylene- based polymers for food contact applications. Such additive systems may be useful, for example, where the polymerization is catalyzed by a metallocene catalyst or by a bimetallic catalyst and/or during polymerization in a condensed mode of operation. In some embodiments, the additive systems may be added to a polymerization reactor to control static levels in the reactor, preventing, reducing, or reversing sheeting, drooling and other discontinuity events resulting from excessive static levels. Polysulfone Additive Systems for use in Food Contact Polymer Products

[0026] Polysulfone additive systems, suitable for use in the production of polymers for food contact applications and end products, may include compositions including a mixture of a polysulfone copolymer, a polymeric polyamine, and oil-soluble sulfonic acid, in a carrier fluid. The carrier fluid (solvent) may include a light hydrocarbon, such as pentane, hexane, or heptane, including the various isomers of each. Other compounds used in the carrier fluid may include various oils, such as those approved for food contact.

[0027] The polysulfone copolymer component of the additive system (often designated as olefin-sulfur dioxide copolymer, olefin polysulfones, or poly(olefin sulfone)) is a polymer, preferably, a linear polymer, wherein the structure is considered to be that of alternating copolymers of the olefins and sulfur dioxide, having a one-to-one molar ratio of the comonomers with the olefins in head to tail arrangement. Preferably the polysulfone copolymer consists essentially of about 50 mole percent (mol%) of units of sulfur dioxide, about 40 to 50 mol% of units derived from one or more 1 -alkenes each having from about 6 to 24 carbon atoms, and from about 0 to 10 mol% of units derived from an olefinic compound having the formula ACH=CHB where A is a group having the formula -(CXH2X)-COOH wherein x is from 0 to about 17, and B is hydrogen or carboxyl, with the provisio that when B is carboxyl, x is 0, and wherein A and B together can be a dicarboxylic anhydride group.

[0028] Preferably, the polysulfone copolymer has a weight average molecular weight in the range of 10,000 to 1,500,000, preferably in the range of 50,000 to 90,000. The units derived from the one or more 1 -alkenes are preferably derived from straight chain alkenes having 6-18 carbon atoms, for example 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, and 1 -octadecene. Examples of units derived from the one or more compounds having the formula ACH=CHB are units derived from maleic acid, acrylic acid, and 5-hexenoic acid. [0029] A preferred polysulfone copolymer is 1-decene polysulfone having an inherent viscosity (measured as a 0.5 weight percent solution in toluene at 30 °C) ranging from about 0.04 dl/g to 1.6 dl/g.

[0030] Further details of suitable polysulfones may be found in U.S. Patent Nos. 3,811,848, 3,917,466, 6,894,127, and 7,476,715, and in GB 1432265A and GB 1432266A. [0031] The polymeric polyamine component of the additive system is preferably a polymeric polyamine having the general formula:

RN[(CH2CHOHCH2NR1)a— (CH2CHOHCH2NR1-R2-NH)b— (CH2CHOHCH2NRS)CH]XH2-X wherein R1 is an aliphatic hydrocarbyl group of 8 to 24 carbon atoms, R2 is an alkylene group of 2 to 6 carbon atoms, R3 is the group -R2— HNR1,

R is R1 or an N-aliphatic hydrocarbyl alkylene group having the formula R1NHR2 — ; a, b, and c are integers of 0-20 and x is 1 or 2, with the provisio that when R is R1 then a is an integer of 2 to 20 and b=c=0, and when R is R1NHR2 — then a is 0 and b+c is an integer of 2 to 20.

[0032] Exemplary polymeric polyamine components are described in U.S. Patent No. 3,917,466, particularly at Column 6 Line 42 to Column 9 Line 29.

[0033] The polymeric polyamine component may be the product of reacting an N-aliphatic hydrocarbyl alkylene diamine or an aliphatic primary amine containing at least 8 carbon atoms and preferably at least 12 carbon atoms with epichlorohydrin. Examples of such aliphatic primary amines are those derived from tall oil, tallow, soy bean oil, coconut oil, and cotton seed oil. The polymeric polyamine derived from the reaction of tallowamine with epichlorohydrin is preferred. A preferred polymeric polyamine is a 1: 1 :5 mole ratio reaction product of N-tallow- 1,3-diaminopropane with epichlorohydrin.

[0034] The oil-soluble sulfonic acid component of the additive system is preferably any oil- soluble sulfonic acid such as an alkanesulfonic acid or an alkylarylsulfonic acid. A useful sulfonic acid is petroleum sulfonic acid resulting from treating oils with sulfuric acid [0035] Preferred oil-soluble sulfonic acids are dodecylbenzene-sulfonic acid and dinonylnapthylsulfonic acid. In a preferred embodiment, the oil-soluble sulfonic acid component of the additive system is dodecylbenzene sulfonic acid.

[0036] The polysulfone additive system preferably comprises 1 to 25 wt% of the polysulfone copolymer, 1 to 25 wt% of the polymeric polyamine, 1 to 25 wt% of the oil-soluble sulfonic acid, and 25 to 95 wt% of the carrier fluid. In some embodiments, the additive system comprises from about 10 to about 30 wt% of the polysulfone copolymer, from about 1 to about 10 wt% of the polymeric polyamine, from about 5 to about 10 wt% of the oil-soluble sulfonic acid, and from about 30 to about 85 wt% of the carrier fluid.

[0037] In some embodiments, the polysulfone additive system may comprise 1 wt.% to 10 wt.% of the polymeric polyamine; 10 wt.% to 30 wt.% of the polysulfone copolymer; 5 wt.% to 10 wt.% of the oil-soluble sulphonic acid; and 40 wt.% to 80 wt.% of the at least one of pentane, hexane, and heptane. The polysulfone additive system may further comprises 1 wt.% to 10 wt.% of the food grade oil.

[0038] In some embodiments, the polysulfone additive system comprises, 12 to 25 wt% of the polysulfone copolymer, from about 2 to about 8 wt% of the polymeric polyamine, and from about 5 to about 10 wt% of the oil-soluble sulfonic acid, and from about 35 wt% to about 85wt% of the light hydrocarbon, and from about 2 wt% to about 10 wt% of the food grade oil. [0039] As used herein, "food grade oil" may refer to any oil, for example, a petroleum-derived mineral oil, that is intended for internal human consumption. It is used as a food additive and as a lubricant in enema preparations. In some embodiments, the sulphonic acid may include one or more of dodecylbenzene sulphonic acid (DDBSA) and dinonylnaphthylsulphonic acid (DINNSA).

[0040] In some embodiments, the polysulfone additive systems suitable for use in the production of polymers for food contact applications and end products may be essentially free of aromatic hydrocarbons, such as toluene, xylenes, and the like. Additionally, polysulfone additive systems suitable for use in the production of polymers for food contact applications and end products may be essentially free of alcohols, such as methanol, isopropanol, and other light (Ci to Ce) alcohols. In some embodiments, polysulfone additive systems according to embodiments disclosed herein may contain less than 0.2 wt.% of a combined amount of toluene, xylenes, methanol, and isopropanol. In other embodiments, polysulfone additive systems according to embodiments disclosed herein may contain less than 0.1 wt.% of a combined amount of toluene, xylenes, methanol, and isopropanol; less than 0.05 wt.% in other embodiments; and less than 0.01 wt.% in yet other embodiments.

[0041] The polysulfone additive system may be fed to polymerization reactors as a solution or as a slurry, thus providing an effective transport medium. As formulated above, the additive system may be diluted in, for example, mineral oil or a light hydrocarbon, such as isopentane or heptane, prior to being fed to a polymerization reactor.

[0042] In some embodiments, the polysulfone additive system may comprises 1 to 10 wt% of the polymeric polyamine, 10 to 30 wt% of the polysulfone copolymer, 5 to 10 wt% of the oil- soluble sulfonic acid, 50 to 80 wt% of the light hydrocarbon, and from 1 to 10% of the food grade oil. The polymeric polyamine may be derived from a vegetable oil. The oil-soluble sulfonic acid may be dodecylbenzene sulphonic acid. The light hydrocarbon may be heptane. The polysulfone additive system may compress less than 0.1 wt% of toluene, and less than 0.1 wt% of iso-propanol, and less than 0.1 wt% of methanol.

[0043] The amount of polysulfone additive system added to the reactor system may depend upon the catalyst system used, as well as reactor pre-conditioning (such as coatings to control static buildup) and other factors known to those skilled in the art. In some embodiments, the polysulfone additive system may be added to the reactor in an amount ranging from 0.01 to 200 ppmw, based on polymer production rate. In other embodiments, the polysulfone additive system may be added to the reactor in an amount ranging from 0.02 to 100 ppmw; or from 0.05 to 50 ppmw; or from 1 to 40 ppmw. In other embodiments, the polysulfone additive system may be added to the reactor in an amount of 2 ppmw or greater, based on polymer production rate. Other suitable ranges for the polysulfone additive system, based on the polymer production weight include lower limits of greater than or equal to 0.01, 0.02, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 10, 12, 15, and upper limits of less than or equal to 200, 150, 100, 75, 50, 40, 30, 25, 20, where the ranges are bounded by any lower and upper limit described above.

[0044] In some embodiments, polysulfone additive systems may be used as or in a reactor coating emplaced during or prior to conducting polymerization reactions within the reactor. In other embodiments, the polysulfone additive system may interact with the particles and other components in the fluidized bed, reducing or neutralizing static charges related to frictional interaction of the catalyst, polymer particles, and reactor vessel.

Continuity Additives

[0045] In addition to the polysulfone additive systems described above, it may also be desired to additionally use one or more additional continuity additives to aid in regulating static levels in the reactor. "Continuity additives" as used herein also includes chemical compositions commonly referred to in the art as "static control agents." Such additional continuity additives, however, should be appropriately selected when used for the production of a product for food contact applications. Due to the enhanced performance of the reactor systems and catalysts that may result via use of a polysulfone additive system as described above, static control agents may be used at a lower concentration in polymerization reactors as compared to use of static control agents alone. Thus, the impact the static control agents have on catalyst productivity may not be as substantial when used in conjunction with polysulfone additive systems according to embodiments disclosed herein.

[0046] As used herein, a static control agent is a chemical composition which, when introduced into a fluidized bed reactor, may influence or drive the static charge (negatively, positively, or to zero) in the fluidized bed. The specific static control agent used may depend upon the nature of the static charge, and the choice of static control agent may vary dependent upon the polymer being produced and the catalyst being used. For example, the use of static control agents is disclosed in European Patent No. 0229368 and U.S. Patent No. 5,283,278. [0047] For example, if the static charge is negative, then static control agents such as positive charge generating compounds may be used. Positive charge generating compounds may include MgO, ZnO, AI2O3, and CuO, for example. In addition, alcohols, oxygen, and nitric oxide may also be used to control negative static charges. See, U.S. Patent Nos. 4,803,251 and 4,555,370. [0048] For positive static charges, negative charge generating inorganic chemicals such as V2O5, Siθ2, Tiθ2, and Fe2θ3 may be used. In addition, water or ketones containing up to 7 carbon atoms may be used to reduce a positive charge.

[0049] In some embodiments, when catalysts such as, metallocene catalysts, are used in a circulating fluidized bed reactor, continuity additives such as aluminum stearate may also be employed. The continuity additive used may be selected for its ability to receive the static charge in the fluidized bed without adversely affecting productivity. Suitable static control agents may also include aluminum distearate and ethoxlated amines.

[0050] Any of the aforementioned continuity additives, as well as those described in, for example, WO 01/44322, listed under the heading Carboxylate Metal Salt and including those chemicals and compositions listed as antistatic agents may be employed either alone or in combination as an additional continuity additive. For example, the carboxylate metal salt may be combined with an amine containing control agent (e.g., a carboxylate metal salt with any family member belonging to the KEMAMINE (available from Crompton Corporation) or ATMER (available from ICI Americas Inc.) family of products).

[0051] Other additional continuity additives useful in embodiments disclosed herein are well known to those in the art. Regardless of which continuity additives are used, care should be exercised in selecting appropriate continuity additives to avoid introduction of poisons into the reactor. In addition, in selected embodiments, the smallest amount of the continuity additives necessary to bring the static charge into alignment with the desired range should be used. [0052] In some embodiments, continuity additives may be added to the reactor as a combination of two or more of the above listed continuity additives, or a combination of an continuity additive and a polysulfone additive system according to embodiments disclosed herein. In other embodiments, continuity additive(s) may be added to the reactor in the form of a solution or a slurry, and may be added to the reactor as an individual feed stream or may be combined with other feeds prior to addition to the reactor. For example, the continuity additives may be combined with the catalyst or catalyst slurry prior to feeding the combined catalyst-static control agent mixture to the reactor.

[0053] In some embodiments, continuity additives may be added to the reactor in an amount ranging from 0.05 to 200 ppmw, or from 2 to 100 ppmw or from 2 to 50 ppmw. In other embodiments, the static control agent may be added to the reactor in an amount of 2 ppmw or greater, based on polymer production rate. Polymerization Process

[0054] Embodiments for producing polyolefin polymer disclosed herein may employ any suitable process for the polymerization of olefins, including any suspension, solution, slurry, or gas phase process, using known equipment and reaction conditions, and are not limited to any specific type of polymerization system. Generally, olefin polymerization temperatures may range from about 0 to about 3000C at atmospheric, sub-atmospheric, or super-atmospheric pressures. In particular, slurry or solution polymerization systems may employ sub- atmospheric, or alternatively, super-atmospheric pressures, and temperatures in the range of about 40 to about 3000C.

[0055] Liquid phase polymerization systems such as those described in U.S. Patent No. 3,324,095, may be used in some embodiments. Liquid phase polymerization systems generally comprise a reactor to which olefin monomers and catalyst compositions are added. The reactor contains a liquid reaction medium which may dissolve or suspend the polyolefin product. This liquid reaction medium may comprise an inert liquid hydrocarbon which is non-reactive under the polymerization conditions employed, the bulk liquid monomer, or a mixture thereof. Although such an inert liquid hydrocarbon may not function as a solvent for the catalyst composition or the polymer obtained by the process, it usually serves as solvent for the monomers used in the polymerization. Inert liquid hydrocarbons suitable for this purpose may include isobutane, isopentane, hexane, cyclohexane, heptane, octane, benzene, toluene, and mixtures and isomers thereof. Reactive contact between the olefin monomer and the catalyst composition may be maintained by constant stirring or agitation. The liquid reaction medium which contains the olefin polymer product and unreacted olefin monomer is withdrawn from the reactor continuously. The olefin polymer product is separated, and the unreacted olefin monomer and liquid reaction medium are typically recycled and fed back into the reactor. [0056] Some embodiments of this disclosure may be especially useful with gas phase polymerization systems, at superatmospheric pressures in the range from 0.07 to 68.9 bar (1 to 1000 psig), from 3.45 to 27.6 bar (50 to 400 psig) in some embodiments, from 6.89 to 24.1 bar (100 to 350 psig) in other embodiments, and temperatures in the range from 30 to 1300C, or from 65 to 1100C, from 75 to 1200C in other embodiments, or from 80 to 1200C in other embodiments. In some embodiments, operating temperatures may be less than 112°C. Stirred or fluidized bed gas phase polymerization systems may be of use in embodiments. [0057] Embodiments for producing polyolefin polymer disclosed herein may also employ a gas phase polymerization process utilizing a fluidized bed reactor. This type reactor, and means for operating the reactor, are well known and are described in, for example, U.S. Patent Nos. 3,709,853; 4,003,712; 4,011,382; 4,302,566; 4,543,399; 4,882,400; 5,352,749; 5,541,270; EP-A- 0 802 202 and Belgian Patent No. 839,380. These patents disclose gas phase polymerization processes wherein the polymerization medium is either mechanically agitated or fluidized by the continuous flow of the gaseous monomer and diluent. As described above, the method and manner for measuring and controlling static charge levels may depend upon the type of reactor system employed.

[0058] Other gas phase processes contemplated include series or multistage polymerization processes. See U.S. Patent Nos. 5,627,242, 5,665,818 and 5,677,375, and European publications EP-A-O 794 200 EP-Bl-O 649 992, EP-A-O 802 202 and EP-B-634 421.

[0059] In general, the polymerization process of the present invention may be a continuous gas phase process, such as a fluid bed process. A fluid bed reactor for use in the process of the present invention typically has a reaction zone and a so-called velocity reduction zone (disengagement zone). The reaction zone includes a bed of growing polymer particles, formed polymer particles and a minor amount of catalyst particles fluidized by the continuous flow of the gaseous monomer and diluent to remove heat of polymerization through the reaction zone. Optionally, some of the recirculated gases may be cooled and compressed to form liquids that increase the heat removal capacity of the circulating gas stream when readmitted to the reaction zone. A suitable rate of gas flow may be readily determined by simple experiment. Makeup of gaseous monomer to the circulating gas stream is at a rate equal to the rate at which particulate polymer product and monomer associated therewith is withdrawn from the reactor, and the composition of the gas passing through the reactor is adjusted to maintain an essentially steady state gaseous composition within the reaction zone. The gas leaving the reaction zone is passed to the velocity reduction zone where entrained particles are removed. Finer entrained particles and dust may be removed in a cyclone and/or fine filter. The gas is passed through a heat exchanger wherein the heat of polymerization is removed, compressed in a compressor and then returned to the reaction zone.

[0060] The process described herein is suitable for the production of homopolymers of olefins, including ethylene, and/or copolymers, terpolymers, and the like, of olefins, including polymers comprising ethylene and at least one or more other olefins. The olefins may be alpha-olefins. The olefins, for example, may contain from 2 to 16 carbon atoms in one embodiment. In other embodiments, ethylene and a comonomer comprising from 3 to 12 carbon atoms, or from 4 to 10 carbon atoms, or from 4 to 8 carbon atoms, may be used.

[0061] In embodiments, polyethylenes may be prepared by the process of the present invention. Such polyethylenes may include homopolymers of ethylene and interpolymers of ethylene and at least one alpha-olefin wherein the ethylene content is at least about 50% by weight of the total monomers involved. Olefins that may be used herein include ethylene, propylene, 1 -butene, 1 - pentene, 1-hexene, 1-heptene, 1-octene, 4-methylpent-l-ene, 1-decene, 1-dodecene, 1- hexadecene and the like. Also usable are polyenes such as 1,3-hexadiene, 1,4-hexadiene, cyclopentadiene, dicyclopentadiene, 4-vinylcyclohex-l-ene, 1,5-cyclooctadiene, 5-vinylidene-2- norbornene and 5-vinyl-2-norbornene, and olefins formed in situ in the polymerization medium. When olefins are formed in situ in the polymerization medium, the formation of polyolefins containing long chain branching may occur.

[0062] Other monomers useful in the process described herein include ethylenically unsaturated monomers, diolefins having 4 to 18 carbon atoms, conjugated or non-conjugated dienes, polyenes, vinyl monomers and cyclic olefins. Non-limiting monomers useful in the invention may include norbornene, norbornadiene, isobutylene, isoprene, vinylbenzocyclobutane, styrenes, alkyl substituted styrene, ethylidene norbornene, dicyclopentadiene and cyclopentene. In another embodiment of the process described herein, ethylene or propylene may be polymerized with at least two different comonomers, optionally one of which may be a diene, to form a terpolymer. [0063] In one embodiment, the content of the alpha-olefin incorporated into the copolymer may be no greater than 30 mol % in total; from 3 to 20 mol % in other embodiments. The term "polyethylene" when used herein is used generically to refer to any or all of the polymers comprising ethylene described above.

[0064] In other embodiments, propylene-based polymers may be prepared by processes disclosed herein. Such propylene-based polymers may include homopolymers of propylene and interpolymers of propylene and at least one alpha-olefin wherein the propylene content is at least about 50% by weight of the total monomers involved. Comonomers that may be used may include ethylene, 1 -butene, 1 -pentene, 1-hexene, 1-heptene, 1-octene, 4-methylpentene-l, 1- decene, 1-dodecene, 1-hexadecene and the like. Also usable are polyenes such as 1,3-hexadiene, 1,4-hexadiene, cyclopentadiene, dicyclopentadiene, 4-vinylcyclohexene-l, 1,5-cyclooctadiene, 5 -vinylidene-2 -norbornene and 5-vinyl-2-norbornene, and olefins formed in situ in the polymerization medium. When olefins are formed in situ in the polymerization medium, the formation of polyolefins containing long chain branching may occur. In one embodiment, the content of the alpha-olefin comonomer incorporated into a propylene-based polymer may be no greater than 49 mol % in total; from 3 to 35 mol % in other embodiments. [0065] Hydrogen gas is often used in olefin polymerization to control the final properties of the polyolefin. Increasing the concentration (partial pressure) of hydrogen may increase the melt flow index (MFI) and/or melt index (MI) of the polyolefin generated. The MFI or MI can thus be influenced by the hydrogen concentration. The amount of hydrogen in the polymerization can be expressed as a mole ratio relative to the total polymerizable monomer, for example, ethylene, or a blend of ethylene and hexene or propylene. The amount of hydrogen used in the polymerization processes of the present invention is an amount necessary to achieve the desired MFI or MI of the final polyolefin resin. Melt flow rate for polypropylene may be measured according to ASTM D 1238 (2300C with 2.16 kg weight); melt index (I2) for polyethylene may be measured according to ASTM D 1238 (1900C with 2.16 kg weight), for example. [0066] Further, a staged reactor employing two or more reactors in series may be used, wherein one reactor may produce, for example, a high molecular weight component, and another reactor may produce a low molecular weight component. In one embodiment of the invention, the polyolefin is produced using a staged gas phase reactor. Such commercial polymerization systems are described in, for example, 2 METALLOCENE-BASED POLYOLEFINS 366-378 (John Scheirs & W. Kaminsky, eds. John Wiley & Sons, Ltd. 2000); U.S. Patent No. 5,665,818, U.S. Patent No. 5,677,375, and EP-A-O 794 200.

[0067] In one embodiment, the one or more reactors in a gas phase or fluidized bed polymerization process may have a pressure ranging from about 0.7 to about 70 bar (about 10 to 1000 psia), or from about 14 to about 42 bar (about 200 to about 600 psia). In one embodiment, the one or more reactors may have a temperature ranging from about 100C to about 1500C, or from about 400C to about 125°C. In one embodiment, the reactor temperature may be operated at the highest feasible temperature taking into account the sintering temperature of the polymer within the reactor. In one embodiment, the superficial gas velocity in the one or more reactors may range from about 0.2 to 1.1 meters/second (0.7 to 3.5 feet/second), or from about 0.3 to 0.8 meters/second (1.0 to 2.7 feet/second).

[0068] In one embodiment, the polymerization process is a continuous gas phase process that includes the steps of: (a) introducing a recycle stream (including ethylene and alpha olefin monomers) into the reactor; (b) introducing the supported catalyst system; (c) withdrawing the recycle stream from the reactor; (d) cooling the recycle stream; (e) introducing into the reactor additional monomer(s) to replace the monomer(s) polymerized; (f) reintroducing the recycle stream or a portion thereof into the reactor; and (g) withdrawing a polymer product from the reactor.

[0069] In embodiments, one or more olefins, C2 to C30 olefins or alpha-olefins, including ethylene or propylene or combinations thereof, may be prepolymerized in the presence of the metallocene catalyst systems described above prior to the main polymerization. The prepolymerization may be carried out batch-wise or continuously in gas, solution or slurry phase, including at elevated pressures. The prepolymerization can take place with any olefin monomer or combination and/or in the presence of any molecular weight controlling agent such as hydrogen. For examples of prepolymerization procedures, see U.S. Patent Nos. 4,748,221, 4,789,359, 4,923,833, 4,921,825, 5,283,278 and 5,705,578 and European publication EP-B-0279 863 and WO 97/44371 .

[0070] The present invention is not limited to any specific type of fluidized or gas phase polymerization reaction and can be carried out in a single reactor or multiple reactors such as two or more reactors in series. In embodiments, the present invention may be carried out in fluidized bed polymerizations (that may be mechanically stirred and/or gas fluidized), or with those utilizing a gas phase, similar to that as described above. In addition to well-known conventional gas phase polymerization processes, it is within the scope of the present invention that "condensing mode," including the "induced condensing mode" and "liquid monomer" operation of a gas phase polymerization may be used.

[0071] Embodiments may employ a condensing mode polymerization, such as those disclosed in U.S. Patent Nos. 4,543,399; 4,588,790; 4,994,534; 5,352,749; 5,462,999; and 6,489,408. Condensing mode processes may be used to achieve higher cooling capacities and, hence, higher reactor productivity. In addition to condensable fluids of the polymerization process itself, other condensable fluids inert to the polymerization may be introduced to induce a condensing mode operation, such as by the processes described in U.S. Patent No. 5,436,304. [0072] Other embodiments may also use a liquid monomer polymerization mode such as those disclosed in U.S. Patent No. 5,453,471; U.S. Ser. No. 08/510,375; PCT 95/09826 (US) and PCT 95/09827 (US). When operating in the liquid monomer mode, liquid can be present throughout the entire polymer bed provided that the liquid monomer present in the bed is adsorbed on or in solid particulate matter present in the bed, such as polymer being produced or inert particulate material (e.g., carbon black, silica, clay, talc, and mixtures thereof), so long as there is no substantial amount of free liquid monomer present. Operating in a liquid monomer mode may also make 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.

[0073] Any type of polymerization catalyst may be used, including liquid- form catalysts, solid catalysts, and heterogeneous or supported catalysts, among others, and may be fed to the reactor as a liquid, slurry (liquid/solid mixture), or as a solid (typically gas transported). Liquid-form catalysts useful in embodiments disclosed herein should be stable and sprayable or atomizable. These catalysts may be used alone or in various combinations or mixtures. For example, one or more liquid catalysts, one or more solid catalysts, one or more supported catalysts, or a mixture of a liquid catalyst and/or a solid or supported catalyst, or a mixture of solid and supported catalysts may be used. These catalysts may be used with co-catalysts, activators, and/or promoters well known in the art. Examples of suitable catalysts include:

A. 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 co-catalyst.

B. Chromium based catalysts, such as those described in U.S. Patent Nos. 3,709,853; 3,709,954; and 4,077,904.

C. Vanadium based catalysts, such as vanadium oxychloride and vanadium acetylacetonate, such as described in U.S. Patent No. 5,317,036.

D. Metallocene catalysts, such as those described in U.S. Patent Nos. 6,933,258 and 6,894,131.

E. Cationic forms of metal halides, such as aluminum trihalides.

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.

H. 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. In various embodiments, neodymium compounds, particularly neodymium neodecanoate, octanoate, and versatate, are particularly useful rare earth metal catalysts. Rare earth catalysts may be used, for example, to polymerize butadiene or isoprene. I. Any combination of one or more of the catalysts above.

[0074] The described catalyst compounds, activators and/or catalyst systems, as noted above, may also be combined with one or more support materials or carriers. For example, in some embodiments, the activator is contacted with a support to form a supported activator wherein the activator is deposited on, contacted with, vaporized with, bonded to, or incorporated within, adsorbed or absorbed in, or on, a support or carrier. [0075] Support materials may include inorganic or organic support materials, such as a porous support material. Non-limiting examples of inorganic support materials include inorganic oxides and inorganic chlorides. Other carriers include resinous support materials such as polystyrene, functionalized or crosslinked organic supports, such as polystyrene divinyl benzene, polyolefins or polymeric compounds, or any other organic or inorganic support material and the like, or mixtures thereof.

[0076] The support materials may include inorganic oxides including Group 2, 3, 4, 5, 13 or 14 metal oxides, such as silica, fumed silica, alumina, silica-alumina and mixtures thereof. Other useful supports include magnesia, titania, zirconia, magnesium chloride, montmorillonite, phyllosilicate, zeolites, talc, clays, and the like. Also, combinations of these support materials may be used, for example, silica-chromium, silica-alumina, silica-titania and the like. Additional support materials may include those porous acrylic polymers described in EP 0 767 184. Other support materials include nanocomposites, as described in PCT WO 99/47598, aerogels, as described in WO 99/48605, spherulites, as described in U.S. Patent No. 5,972,510, and polymeric beads, as described in WO 99/50311.

[0077] Support material, such as inorganic oxides, may have a surface area in the range from about 10 to about 700 m2/g, a pore volume in the range from about 0.1 to about 4 cc/g, and an average particle size in the range from about 0.1 to about 1000 μm. In other embodiments, the surface area of the support may be in the range from about 50 to about 500 m2/g, the pore volume is from about 0.5 to about 3.5 cc/g, and the average particle size is from about 1 to about 500 μm. In yet other embodiments, the surface area of the support is in the range from about 100 to about 1000 m2/g, the pore volume is from about 0.8 to about 5.0 cc/g, and the average particle size is from about 1 to about 100 μm, or from about 1 to about 60 μm. The average pore size of the support material may be in the range from 10 to 1000 A; or from about 50 to about 500 A; or from about 75 to about 450 A.

[0078] There are various methods known in the art for producing a supported activator or combining an activator with a support material. In an embodiment, the support material is chemically treated and/or dehydrated prior to combining with the catalyst compound, activator and/or catalyst system. In a family of embodiments, the support material may have various levels of dehydration, such as may be achieved by drying the support material at temperatures in the range from about 1000C to about 10000C.

[0079] In some embodiments, dehydrated silica may be contacted with an organoaluminum or alumoxane compound. In the embodiment wherein an organoaluminum compound is used, the activator is formed in situ in the support material as a result of the reaction of, for example, trimethylaluminum and water.

[0080] In yet other embodiments, Lewis base-containing support substrates will react with a Lewis acidic activator to form a support bonded Lewis acid compound. The Lewis base hydroxyl groups of silica are exemplary of metal/metalloid oxides where this method of bonding to a support occurs. These embodiments are described in, for example, U.S. Patent No. 6,147,173.

[0081] Other embodiments of supporting an activator are described in U.S. Patent No. 5,427,991, where supported non-coordinating anions derived from trisperfluorophenyl boron are described; U.S. Patent No. 5,643,847, discusses the reaction of Group 13 Lewis acid compounds with metal oxides such as silica and illustrates the reaction of trisperfluorophenyl boron with silanol groups (the hydroxyl groups of silicon) resulting in bound anions capable of protonating transition metal organometallic catalyst compounds to form catalytically active cations counterbalanced by the bound anions; immobilized Group IIIA Lewis acid catalysts suitable for carbocationic polymerizations are described in U.S. Patent No. 5,288,677; and James C. W. Chien, Jour. Poly. ScL: Pt A: Poly. Chem, Vol. 29, 1603-1607 (1991), describes the olefin polymerization utility of methylalumoxane (MAO) reacted with silica (Siθ2) and metallocenes and describes a covalent bonding of the aluminum atom to the silica through an oxygen atom in the surface hydroxyl groups of the silica.

[0082] In some embodiments, the supported activator is formed by preparing, in an agitated, temperature and pressure controlled vessel, a solution of the activator and a suitable solvent, then adding the support material at temperatures from 00C to 1000C, contacting the support with the activator solution for up to 24 hours, then using a combination of heat and pressure to remove the solvent to produce a free flowing powder. Temperatures can range from 40 to 1200C and pressures from 5 psia to 20 psia (34.5 to 138 kPa). An inert gas sweep can also be used in assist in removing solvent. Alternate orders of addition, such as slurrying the support material in an appropriate solvent then adding the activator, can be used.

[0083] In an embodiment, the weight percent of the activator to the support material is in the range from about 10 weight percent to about 70 weight percent, or in the range from about 15 weight percent to about 60 weight percent, or in the range from about 20 weight percent to about 50 weight percent, or in the range from about 20 weight percent to about 40 weight percent in other embodiments.

[0084] Conventional supported catalysts system useful in embodiments disclosed herein include those supported catalyst systems that are formed by contacting a support material, an activator and a catalyst compound in various ways under a variety of conditions outside of a catalyst feeder apparatus. Examples of conventional methods of supporting metallocene catalyst systems are described in U.S. Patent Nos. 4,701,432, 4,808,561, 4,912,075, 4,925,821, 4,937,217, 5,008,228, 5,238,892, 5,240,894, 5,332,706, 5,346,925, 5,422,325, 5,466,649, 5,466,766, 5,468,702, 5,529,965, 5,554,704, 5,629,253, 5,639,835, 5,625,015, 5,643,847, 5,665,665, 5,698,487, 5,714,424, 5,723,400, 5,723,402, 5,731,261, 5,759,940, 5,767,032, 5,770,664, 5,846,895, 5,939,348, 546,872, 6,090,740 and PCT publications WO 95/32995, WO 95/14044, WO 96/06187 and WO 97/02297, and EP-Bl-O 685 494.

[0085] The catalyst components, for example a catalyst compound, activator and support, may be fed into the polymerization reactor as a mineral oil slurry. Solids concentrations in oil may range from about 1 to about 50 weight percent, or from about 10 to about 25 weight percent. [0086] The catalyst compounds, activators and or optional supports used herein may also be spray dried separately or together prior to being injected into the reactor. The spray dried catalyst may be used as a powder or solid or may be placed in a diluent and slurried into the reactor. In other embodiments, the catalyst compounds and activators used herein are not supported.

[0087] Catalysts useful in various embodiments disclosed herein may include conventional Ziegler-Natta catalysts and chromium catalysts. Illustrative Ziegler-Natta catalyst compounds are disclosed in ZIEGLER CATALYSTS 363-386 (G. Fink, R. Mulhaupt and H. H. Brintzinger, eds., Springer-Verlag 1995); or in EP 103 120; EP 102 503; EP 0 231 102; EP 0 703 246; RE 33,683; U.S. Pat. Nos. 4,302,565; 5,518,973; 5,525,678; 5,288,933; 5,290,745; 5,093,415 and 6,562,905. Examples of such catalysts include those having Group 4, 5 or 6 transition metal oxides, alkoxides and halides, or oxides, alkoxides and halide compounds of titanium, zirconium or vanadium; optionally in combination with a magnesium compound, internal and/or external electron donors (alcohols, ethers, siloxanes, etc.), aluminum or boron alkyl and alkyl halides, and inorganic oxide supports.

[0088] In one or more embodiments, conventional-type transition metal catalysts can be used. Conventional type transition metal catalysts include traditional Ziegler-Natta catalysts in U.S. Pat. Nos. 4,115,639, 4,077,904, 4,482,687, 4,564,605, 4,721,763, 4,879,359 and 4,960,741. Conventional-type transition metal catalysts can be represented by the formula: MRx, where M is a metal from Groups 3 to 17, or a metal from Groups 4 to 6, or a metal from Group 4, or titanium; R is a halogen or a hydrocarbyloxy group; and x is the valence of the metal M. Examples of R include alkoxy, phenoxy, bromide, chloride and fluoride. Preferred conventional- type transition metal catalyst compounds include transition metal compounds from Groups 3 to 17, or Groups 4 to 12, or Groups 4 to 6.

[0089] Conventional-type transition metal catalyst compounds based on magnesium/titanium electron-donor complexes are described in, for example, U.S. Pat. Nos. 4,302,565 and 4,302,566. Catalysts derived from Mg/Ti/Cl/THF are also contemplated, which are well known to those of ordinary skill in the art.

[0090] Suitable chromium catalysts include di-substituted chromates, such as Crθ2(OR)2; where R is triphenylsilane or a tertiary polyalicyclic alkyl. The chromium catalyst system can further include Crθ3, chromocene, silyl chromate, chromyl chloride (CrO2Cl2), chromium-2-ethyl- hexanoate, chromium acetylacetonate (Cr(AcAc) 3), and the like. Illustrative chromium catalysts are further described in U.S. Pat. Nos. 3,709,853; 3,709,954; 3,231,550; 3,242,099; and 4,077,904.

[0091] Metallocenes are generally described throughout in, for example, 1 & 2 METALLOCENE-BASED POLYOLEFΓNS (John Scheirs & W. Kaminsky eds., John Wiley & Sons, Ltd. 2000); G. G. Hlatky in 181 COORDINATION CHEM. REV. 243-296 (1999) and in particular, for use in the synthesis of polyethylene in 1 METALLOCENE-BASED POLYOLEFINS 261-377 (2000). The metallocene catalyst compounds can include "half sandwich" and "full sandwich" compounds having one or more Cp ligands (cyclopentadienyl and ligands isolobal to cyclopentadienyl) bound to at least one Group 3 to Group 12 metal atom, and one or more leaving group(s) bound to the at least one metal atom. Hereinafter, these compounds will be referred to as "metallocenes" or "metallocene catalyst components." [0092] The Cp ligands are one or more rings or ring system(s), at least a portion of which includes pi-bonded systems, such as cycloalkadienyl ligands and heterocyclic analogues. The ring(s) or ring system(s) typically include atoms selected from Groups 13 to 16 atoms, or the atoms that make up the Cp ligands can be selected from carbon, nitrogen, oxygen, silicon, sulfur, phosphorous, germanium, boron and aluminum and combinations thereof, wherein carbon makes up at least 50% of the ring members. Or, the Cp ligand(s) can be selected from substituted and unsubstituted cyclopentadienyl ligands and ligands isolobal to cyclopentadienyl, non-limiting examples of which include cyclopentadienyl, indenyl, fluorenyl and other structures. Further non-limiting examples of such ligands include cyclopentadienyl, cyclopentaphenanthreneyl, indenyl, benzindenyl, fluorenyl, octahydrofluorenyl, cyclooctatetraenyl, cyclopentacyclododecene, phenanthrindenyl, 3,4-benzofluorenyl, 9- phenylfluorenyl, 8-H-cyclopent[a]acenaphthylenyl, 7H-dibenzofluorenyl, indeno[l,2- 9]anthrene, thiophenoindenyl, thiophenofluorenyl, hydrogenated versions thereof (e.g., 4,5,6,7- tetrahydroindenyl, or "H4lnd"), substituted versions thereof, and heterocyclic versions thereof. [0093] In one or more embodiments, a "mixed" catalyst system or "multi-catalyst" system may be used. A mixed catalyst system includes at least one metallocene catalyst component and at least one non-metallocene component. The mixed catalyst system may be described as a bimetallic catalyst composition or a multi-catalyst composition. As used herein, the terms "bimetallic catalyst composition" and "bimetallic catalyst" include any composition, mixture, or system that includes two or more different catalyst components, each having the same or different metal group but having at least one different catalyst component, for example, a different ligand or general catalyst structure. Examples of useful bimetallic catalysts are in U.S. Patent Nos. 6,271,325, 6,300,438, and 6,417,204. The terms "multi-catalyst composition" and "multi-catalyst" include any composition, mixture, or system that includes two or more different catalyst components regardless of the metals. Therefore, terms "bimetallic catalyst composition," "bimetallic catalyst," "multi-catalyst composition," and "multi-catalyst" will be collectively referred to herein as a "mixed catalyst system" unless specifically noted otherwise. Any one or more of the different catalyst components can be supported or non-supported. [0094] Use of prior art continuity additives, in general, may enhance polymerization reactor operations by reducing the occurrence of sheeting and drooling. However, productivity of various catalysts may be adversely affected by use of such continuity additives. For example, it has been observed that for certain bimodal catalyst systems, use of various continuity additives may decrease catalyst productivity by up to 40% or more. Further, reactor operations may be sensitive when using such continuity additives, often requiring a continuous flow of continuity additive, and where a slight decrease in continuity additive concentration may result in immediate skin thermocouple excursions. In contrast, polysulfone additive systems according to embodiments disclosed herein may be used without significant detriment to catalyst productivity, including use with bimetallic catalysts and metallocene catalysts. Further, when using polysulfone additive systems according to embodiments disclosed herein, it may be possible to run a reactor for an extended time following loss or stoppage of additive flow to the reactor.

[0095] Processes disclosed herein may optionally use inert particulate materials as fluidization aids. These inert particulate materials can include carbon black, silica, talc, and clays, as well as inert polymeric materials. Carbon black, for example, has a primary particle size of about 10 to about 100 nanometers, an average size of aggregate of about 0.1 to about 30 microns, and a specific surface area from about 30 to about 1500 m2/g. Silica has a primary particle size of about 5 to about 50 nanometers, an average size of aggregate of about 0.1 to about 30 microns, and a specific surface area from about 50 to about 500 m /g. Clay, talc, and polymeric materials have an average particle size of about 0.01 to about 10 microns and a specific surface area of about 3 to 30 m2/g. These inert particulate materials may be used in amounts ranging from about 0.3 to about 80%, or from 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.

[0096] Chain transfer agents, promoters, scavenging agents and other additives may be, and often are, used in the polymerization processes disclosed herein. Chain transfer agents are often used to control polymer molecular weight. Examples of these compounds are hydrogen and metal alkyls of the general formula MxRy, where M is a Group 3-12 metal, x is the oxidation state of the metal, typically 1, 2, 3, 4, 5 or 6, each R is independently an alkyl or aryl, and y is 0, 1, 2, 3, 4, 5, or 6. In some embodiments, a zinc alkyl is used, such as diethyl zinc. Typical promoters may include halogenated hydrocarbons such as CHCI3, CFCI3, CH3-CCI3, CF2Cl- CCI3, and ethyltrichloroacetate. 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 used to increase catalyst activity. Examples of these compounds include metal alkyls, such as aluminum alkyls, for example, 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 from positive to negative or from negative to positive. The use of these additives is well within the skill of those skilled in the art. These additives may be added to the circulation loops, riser, and/or downer 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.

[0097] In one embodiment of the process of the invention, the gas phase process may be operated in the presence of a metallocene-type catalyst system and in the absence of, or essentially free of, any scavengers, such as triethylaluminum, trimethylaluminum, triisobutylaluminum and tri-n-hexylaluminum and diethyl aluminum chloride, dibutyl zinc, and the like. By "essentially free," it is meant that these compounds are not deliberately added to the reactor or any reactor components, and if present, are present in the reactor at less than 1 ppm. [0098] In some embo