EP0910470A1 - Catalyseurs a forte activite pour la preparation de polyethylene avec une repartition intermediaire des poids moleculaires - Google Patents

Catalyseurs a forte activite pour la preparation de polyethylene avec une repartition intermediaire des poids moleculaires

Info

Publication number
EP0910470A1
EP0910470A1 EP97932291A EP97932291A EP0910470A1 EP 0910470 A1 EP0910470 A1 EP 0910470A1 EP 97932291 A EP97932291 A EP 97932291A EP 97932291 A EP97932291 A EP 97932291A EP 0910470 A1 EP0910470 A1 EP 0910470A1
Authority
EP
European Patent Office
Prior art keywords
catalyst
ethylene
molecular weight
reactor
electron donor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97932291A
Other languages
German (de)
English (en)
Other versions
EP0910470A4 (fr
Inventor
Robert Ivan Mink
Thomas Edward Nowlin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ExxonMobil Oil Corp
Original Assignee
Mobil Oil Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mobil Oil Corp filed Critical Mobil Oil Corp
Publication of EP0910470A1 publication Critical patent/EP0910470A1/fr
Publication of EP0910470A4 publication Critical patent/EP0910470A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/12—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides
    • B01J31/122—Metal aryl or alkyl compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/12—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides
    • B01J31/14—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides of aluminium or boron
    • B01J31/143—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides of aluminium or boron of aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
    • B01J31/38—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24 of titanium, zirconium or hafnium
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • the present invention relates to a method for polymerizing alpha-olefins, a catalyst for such a polymerization method and a method for producing such a catalyst.
  • the present invention relates to a catalyst, and a method for preparation thereof, which produces high density polyethylene or linear low density polyethylene (LLDPE) having an intermediate molecular weight distribution, as evidenced by relatively intermediate values of melt flow ratio (MFR) , suitable for film applications.
  • LLDPE linear low density polyethylene
  • MFR melt flow ratio
  • the invention is also directed to a highly productive polymerization process carried out with the catalyst of the invention.
  • ethylene homopolymers and ethylene/1-olefin copoly ers with either a very narrow molecular weight distribution (MWD) or very broad MWD are important.
  • MWD molecular weight distribution
  • recently polymer with intermediate MWDs have been found to be important for blending two or more polymer samples into commercially important products, e.g., for film or blow-molding applications.
  • the two or more polymer samples which are blended into the final product each may have a very different molecular weight.
  • One polymer sample will usually have a relatively very high molecular weight as indicated by a High Load Melt Index (HLMI) of 0.4 - 5, while the other polymer sample will have arelatively very low molecular weight as indicated by a Melt Index (MI) of 20-1000.
  • HLMI High Load Melt Index
  • MI Melt Index
  • melt flow ratio is the ratio of high load melt index (HLMI or I ) to melt index (I ) for a given resin.
  • the melt flow ratio is believed to be an indication of the molecular weight distribution of the polymer, the higher the value, the broader the molecular weight distribution.
  • Resins having relatively very low MFR values e.g., of 15 to 30, have relatively narrow molecular weight distribution.
  • resins with relatively high MFR values i.e. 80-150
  • Resins with an intermediate MWD have MFR values of 30-70.
  • a supported alpha-olefin polymerization catalyst composition of this invention of improved activity as measured by productivity is prepared in a multi-step process.
  • An ethylene homopolymerization or ethylene copolymer- ization catalyst is formed by:
  • the catalyst also produces polymers having relatively an intermediate molecular weight distribution, high activity and good Flow Index response.
  • the polymers prepared in the presence of the catalyst composition of this invention are linear polyethylenes with short chain branching which are homopolymers of ethylene or copolymers of ethylene and higher alpha-olefins.
  • the polymers exhibit relatively intermediate values of melt flow ratio (MFR) , as compared to similar polymers prepared in the presence of previously-known catalyst compositions.
  • MFR melt flow ratio
  • the polymers prepared with the catalyst compositions of the invention are especially suitable as components for the production of resins used in film and blow molding applications.
  • Catalysts produced according to the present invention are described below in terms of the manner in which they are made.
  • the carrier material is a solid, particulate, porous, preferably inorganic material.
  • These carrier materials include inorganic materials, such as oxides of silicon and/or aluminum.
  • the carrier material is used in the form of a dry powder having an average particle size of from 1 micron to
  • the carrier material is also porous and has a surface area of at
  • the carrier material should be dry, that is, free of absorbed water. Drying of the carrier material can be effected by heating at 100° to 1000°C, preferably at 600°C. When the carrier is silica, it is heated at at least 200°C, preferably 200° to 850°C and most preferably at 600°C.
  • the carrier material must have at least some active hydroxyl (OH) groups to produce the catalyst composition of this invention.
  • the carrier is silica which, prior to the use thereof in the first catalyst synthesis step, has been dehydrated by fluidizing it with nitrogen and heating at 600 C C for 16 hours to achieve a surface hydroxyl group concentration of 0.7 millimoles per gram (mmols/gm) .
  • the silica is in the form of spherical particles, e.g., as obtained by a spray-drying process.
  • the carrier material is slurried in a non-polar solvent and the resulting slurry is contacted with at least one organomagnesium composition having the empirical formula (I) .
  • the slurry of the carrier material in the solvent is prepared by introducing the carrier into the solvent, preferably while stirring, and heating the mixture to 25° to 100°C, preferably to 40° to 60°C. The slurry is then contacted with the aforementioned organomagnesium composition, while the heating is continued at the aforementioned temperature.
  • the organomagnesium composition has the empirical formula Rm Mg R n where R and R are the same or different
  • C -C 2 alkyl groups preferably C -C 0 alkyl groups, more preferably C -C 8 normal alkyl groups, and most preferably both R and R are butyl groups, and m and n are each 0, 1 or 2, providing that m + n is equal to the valence of Mg.
  • Suitable non-polar solvents are materials in which all of the reactants used herein, i.e., the organomagnesium composition (R MgR'n) transition metal compound, and the oxygen containing electron donor compound are at least partially soluble and which are liquid at reaction temperatures herein.
  • Preferred non-polar solvents are alkanes, such as isopentane, hexane, n-heptane, octane, nonane, and decane, although a variety of other materials including cycloalkanes, such as cyclohexane, aromatics, such as benzene and ethylbenzene, may also be employed.
  • the most preferred non-polar solvent is hexane.
  • the non-polar solvent should be purified, such as by percolation through silica gel and/or molecular sieves, to remove traces of water, oxygen, polar compounds, and other materials capable of adversely affecting catalyst activity.
  • the synthesis of this catalyst it is important to add only such an amount of the organomagnesium composition that will be deposited, physically or chemically, onto the support since any excess of the organomagnesium composition in the solution may react with other synthesis chemicals and precipitate outside of the support.
  • the carrier drying temperature affects the number of sites on the carrier available for the organomagnesium composition - the higher the drying temperature the lower the number of sites.
  • the exact molar ratio of the organomagnesium composition to the hydroxyl groups will vary and must be determined on a case-by-case basis to assure that only so much of the organomagnesium composition is added to the solution as will be deposited onto the support without leaving any excess of the organomagnesium composition in the solution.
  • the molar amount of the organomagnesium composition deposited onto the support is greater than the molar content of the hydroxyl groups on the support.
  • the molar ratios given below are intended only as an approximate guideline and the exact amount of the organomagnesium composition in this embodiment must be controlled by the functional limitation discussed above, i.e., it must not be greater than that which can be deposited onto the support. If greater than that amount is added to the solvent, the excess may react with the other compounds used in the preparation thereby forming a precipitate outside of the support which is detrimental in the synthesis of our catalyst and must be avoided.
  • the amount of the organomagnesium composition which is not greater than that deposited onto the support can be determined in any conventional manner, e.g., by adding the organomagnesium composition to the slurry of the carrier in the solvent, while stirring the slurry, until the organomagnesium composition is detected as a solution in the solvent.
  • the amount of the organomagnesium composition added to the slurry is such that the molar ratio of Mg to the hydroxyl groups (OH) on the solid carrier is 1:1 to 3:1, preferably 1.1:1 to 2:1, more preferably 1.2:1 to 1.8:1 and most preferably 1.4:1.
  • the organomagnesium composition dissolves in the non- polar solvent to form a solution from which the organomagnesium composition is deposited onto the carrier. It is also possible to add such an amount of the organomagnesium composition which is in excess of that which will be deposited onto the support, and then remove, e.g., by filtration and washing, any excess of the organomagnesium composition. However, this alternative is less desirable than the most preferred embodiment described above.
  • the slurry is contacted with at least one transition metal compound soluble in the non-polar solvent.
  • This synthesis step is conducted at 25° to 75°C, preferably at 30° to 65°C, and most preferably at 40° to 55°C.
  • the amount of the transition metal compound added is not greater than that which can be deposited onto the carrier.
  • the exact molar ratio of Mg to the transition metal and of the transition metal to the hydroxyl groups of the carrier will therefore vary (depending, e.g., on the carrier drying temperature) and must be determined on a case-by-case basis.
  • the amount of the transition metal compound is such that the molar ratio of the transition metal, derived from the transition metal compound, to the hydroxyl groups of the carrier is 1 to 2.0, preferably 1.2 to 1.8.
  • the amount of the transition metal compound is also such that the molar ratio of Mg to the transition metal is 0.5 to 3, preferably 1 to 2. It was found that these molar ratios produce a catalyst composition which produces resins having relatively intermediate melt flow ratio values of 30 to 60.
  • Suitable transition metal compounds used herein are compounds of metals of Groups 4 and 5 of the Periodic Chart of the Elements, as published by Chemical and Engineering News, 63(5), 27, 1985, providing that such compounds are soluble in the non-polar solvents.
  • Non-limiting examples of such compounds are titanium and vanadium halides, e.g., titanium tetrachloride, TiCl 4 , vanadium tetrachloride, VC1., vanadium oxytrichloride, V0C1_, titanium and vanadium alkoxides, wherein the alkoxide moiety has a branched or unbranched alkyl radical of 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms.
  • the preferred transition metal compounds are titanium compounds, preferably tetravalent titanium compounds.
  • the most preferred titanium compound is titanium tetrachloride. Mixtures of such transition metal compounds may also be used and generally no restrictions are imposed on the transition metal compounds which may be included. Any transition metal compound that may be used alone may also be used in conjunction with other transition metal compounds.
  • Oxygen-containing electron donors used in the catalyst synthesis are of the formula R COOR_ and R -O-R , or R 4 ⁇ 0H, respectively.
  • R ⁇ and R_ may be the same or different and each can contain 1 to 15 carbon atoms.
  • Each of and R 2 may be alkyl, aryl, alkyl substituted aryl; R and R may be the same or different and each can contain 1 to 15 carbon atoms and may be alkyl, aryl, alkyl substituted aryl or aryl substituted alkyl, or alkylene; comprehended by this definition is that R_ and R together may form alkylene groups thereby defining R 3 OR. as a cyclic ether.
  • Preferred oxygen containing electron donors include p-cresol, methanol, ethyl benzoate, tetrahydrofuran, and n-butyl ether. Most preferably, the oxygen containing electron donor is ethyl benzoate, tetrahydrofuran or n-butylether.
  • the electron donor is an ester or an ether which is added to the catalyst synthesis after transition metal addition to the synthesis slurry.
  • the electron donors (ED) are added in amounts, effective to increase the productivity of the catalyst and its selectivity for polymers produced with MFRs ranging from 30 to 60 at HLMI ranging from 0.1 to 40,000. Practically, such amounts range from a Ti/ED molar ratio of 0.5 to 2.0.
  • the non-polar solvent is slowly removed, e.g., by distillation or evaporation after precursor formation.
  • the temperature at which the non-polar solvent is removed from the synthesis mixture affects the productivity of the resulting catalyst composition.
  • Lower solvent removal temperatures produce catalyst compositions which are substantially more active than those produced with higher solvent removal temperatures. For this reason, it is preferred to remove the non-polar solvent at 40° to 65°C, preferably at 45° to 55°C and most preferably at 55°C by drying, distillation or evaporation or any other conventional means.
  • the resulting free-flowing powder referred to herein as a catalyst precursor, is combined with an organoaluminum activator.
  • an organoaluminum activator is used in an amount which is at least effective to promote the polymerization activity of the solid catalyst component of this invention.
  • the amount of the activator is sufficient to give an Al:Ti molar ratio of 15:1 to 1000:1, preferably 20:1 to 300:1, and most preferably 25:1 to 100:1.
  • the catalyst composition of this invention is produced by chemically impregnating the support with catalyst components sequentially added to the slurry of the carrier in the non-polar solvent. Therefore, all of the catalyst synthesis chemical ingredients must be soluble in the non-polar solvent used in the synthesis. The order of addition of the reagents may also be important since the catalyst synthesis procedure is predicated on the chemical reaction between the chemical ingredients sequentially added to the non-polar solvent (a liquid) and the solid carrier material or a catalyst intermediate supported by such a material (a solid) . Thus, the reaction is a solid-liquid reaction.
  • the catalyst synthesis procedure must be conducted in such a manner as to avoid the reaction of two or more reagents in the non-polar solvent to form a reaction product insoluble in the non-polar solvent outside of the pores of the solid catalyst support.
  • Such an insoluble reaction product would be incapable of reacting with the carrier or the catalyst intermediate and therefore would not be incorporated onto the solid support of the catalyst composition.
  • the catalyst precursors of the present invention are prepared in the substantial absence of water, oxygen, and other catalyst poisons. Such catalyst poisons can be excluded during the catalyst preparation steps by any well known methods, e.g., by carrying out the preparation under an atmosphere of nitrogen, argon or other inert gas.
  • An inert gas purge can serve the dual purpose of excluding external contaminants during the preparation and removing undesirable reaction by-products resulting from the preparation of the neat, liquid reaction product. Purification of the non-polar solvent employed in the catalyst is also helpful in this regard.
  • the catalyst may be activated in situ by adding the activator and catalyst separately to the polymerization medium. It is also possible to combine the catalyst and the activator before the introduction thereof into the polymerization medium, e.g., for up to 2 hours prior to the introduction thereof into the polymerization medium at a temperature of from -40° to 100°C.
  • Ethylene homopolymers or ethylene/1-olefin copolymers are polymerized with the catalysts prepared according to the present invention by any suitable process.
  • Such processes include polymerizations carried out in suspension, in solution or in the gas phase.
  • Gas phase polymerization reactions are preferred, e.g. , those taking place in stirred bed reactors and, especially, fluidized bed reactors.
  • the molecular weight of the polymer may be controlled in a known manner, e.g., by using hydrogen.
  • molecular weight may be suitably controlled with hydrogen when the polymeri- zation is carried out at relatively low temperatures, e.g., from 30° to 105°C. This control of molecular weight may be evidenced by measurable positive change in melt index (I ) of the polymer produced.
  • MFR molecular weight distribution of the polymers prepared in the presence of the catalysts of the present invention, as expressed by the MFR values, varies from 30 to 60, preferably 32 to 50. As is known to those skilled in the art, such MFR values are indicative of a relatively intermediate molecular weight distribution of the polymer. As is also known to those skilled in the art, such MFR values are indicative of the polymers especially suitable as components for polymers used for film or blow molding applications. MFR is defined herein as the ratio of the high load melt index (HLMI or I 21 ) divided by the melt index, i.e. ,
  • the catalysts prepared according to the present invention are highly active and may have an activity of at least 1 to 5 kilograms of polymer per gram of catalyst per 100 psi of ethylene in 1 hour.
  • the polyethylene polymers prepared in accordance with the present invention are homopolymers of ethylene or copolymers of ethylene with one or more C -C.0 alpha-olefins.
  • copolymers having two monomeric units are possible as well as terpolymers having three monomeric units.
  • Particular examples of such polymers include ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1-octene copolymers, ethylene/4-methyl/1-pentene copolymers, ethylene/ 1-butene/l-hexene terpolymers, ethylene/propylene/1-hexene terpolymers and ethylene/propylene/1-butene terpolymers.
  • the polyethylene polymers produced in accordance with the present invention preferably contain at least 80 percent by weight of ethylene units.
  • a particularly desirable method for producing polyethylene polymers according to the present invention is in a fluid bed reactor. Such a reactor and means for operating it are described by Levine et al, U.S. Patent No. 4,011,382, Karol et al , U.S. Patent 4,302, 566 and by Nowlin et al, U.S. Patent 4,481,301, the entire contents of all of which are incorporated herein by reference.
  • the polymer produced in such a reactor contains the catalyst particles because the catalyst is not separated from the polymer.
  • bimodal ethylene polymer blends having a desirable combination of processability and mechanical properties are produced by a process including the steps of polymerizing gaseous monomeric compositions comprising a major proportion of ethylene in at least two gas phase, fluidized bed reactors operating in the tandem mode under the following conditions.
  • a gas comprising monomeric composition and, optionally, a small amount of hydrogen is contacted under polymerization conditions with a catalyst of the invention, at a hydrogen/ethylene molar ratio of no higher than 0.3 and an ethylene partial pressure no higher than 100 psia such as to produce a relatively high molecular weight (HMW) polymer powder wherein the polymer is deposited on the catalyst particles.
  • HMW relatively high molecular weight
  • the HMW polymer powder containing the catalyst is then transferred to a second reactor with, optionally, additional activator (or cocatalyst) which may be the same or different from the cocatalyst utilized in the first reactor but with no additional transition metal catalyst component, together with a gaseous mixture comprising hydrogen and monomeric composition wherein additional polymerization is carried out at a hydrogen/ethylene molar ratio of at least 0.9, the ratio being sufficiently high such that it is at least 8.0 times that in the first reactor, and an ethylene partial pressure at least 1.7 times that in the first reactor, to produce a relatively low molecular weight (LMW) polymer much of which is deposited on and within the HMW polymer/catalyst particles from the first reactor, such that the fraction of HMW polymer in the bimodal polymer leaving the second reactor is at least 0.35.
  • additional activator or cocatalyst
  • the foregoing conditions provide for a process wherein the production of fines tending to foul compressors and other equipment is kept to a relatively low level. Moreover, such conditions provide for an inhibited level of productivity in the first reactor with a resulting increased level of productivity in the second reactor to produce a bimodal polymer blend having a favorable melt flow ratio (MFR, an indication of molecular weight distribution) and a high degree of homogeneity (indicated by low level of gels and low heterogeneity index) caused by a substantial degree of blending of HMW and LMW polymer in each final polymer particle inherently resulting from the process operation.
  • MFR melt flow ratio
  • the bimodal blend is capable of being processed without undue difficulty into films and containers for household industrial chemicals having a superior combination of mechanical properties.
  • the gaseous monomer entering both reactors may consist wholly of ethylene or may comprise a preponderance of ethylene and a minor amount of a comonomer such as a alpha- olefin containing 3 to 10 carbon atoms.
  • the comonomer may be present in the monomeric compositions entering either or both reactors . In many cases, the monomer composition will not be the same in both reactors.
  • the monomer entering the first reactor contain a minor amount of comonomer such as 1-hexene so that the HMW component of the bimodal product is a copolymer, whereas the monomer fed to the second reactor consists essentially of ethylene so that the LMW component of the product is substantially an ethylene homopolymer.
  • the molar ratio of comonomer to ethylene may be in the range, for example, of 0.005 to 0.7, preferably 0.04 to 0.6.
  • Hydrogen may or may not be used to modulate the molecular weight of the HMW polymer made in the first reactor.
  • hydrogen may be fed to the first reactor such that the molar ratio of hydrogen to ethylene (H 2 /C ratio) is, for example, up to 0.3, preferably 0.005 to 0.2.
  • H 2 /C ratio the molar ratio of hydrogen to ethylene
  • the second reactor it is necessary to produce a LMW polymer with a low enough molecular weight and in sufficient quantity so as to produce a bimodal resin which can be formed, with a minimum of processing difficulties, into end use products such as films and containers for household industrial chemicals having a superior combination of mechanical properties.
  • hydrogen is fed to the second reactor with the ethylene containing monomer such that the hydrogen to ethylene mole ratio in the gas phase is 0.9, preferably in the range of 0.9 to 5.0 and most preferably in the range of 1.0 to 3.5.
  • the hydrogen to ethylene mole ratios in the two reactors should be such that the ratio in the second reactor is at least 8.0 times the ratio in the first reactor, for example in the range 8.0 to 10,000 times such ratio, and preferably 10 to 200 times the ratio in the first reactor.
  • a significant part of this invention lies in the discovery that this effect can be largely overcome by employing ethylene partial pressures in the two reactors so as to reduce the polymer productivity in the first reactor and raise such productivity in the second reactor.
  • the ethylene partial pressure employed in the first reactor is no higher than 100 psia, for example in the range of 15 to 100 psia, preferably in the range of 20 to 80 psia and the ethylene partial pressure in the second reactor is, for example in the range of 26 to 170 psia, preferably 45 to 120 psia, with the ethylene partial pressures in any specific process being such that the ratio of ethylene partial pressure in the second to that in the first reactor is 1.7, preferably 1.7 to 7.0, and more preferably 2.0 to 4.0.
  • an inert gas such as nitrogen may also be present in one or both reactors in addition to the monomer and hydrogen.
  • the total pressure in both reactors may be in the range, for example, of 100 to 600 psig, preferably 200 to 350 psig.
  • the temperature of polymerization in the first reactor may be in the range, for example, of 60° to 130°C, preferably 60° to 90°C, while the temperature in the second reactor may be in the range, for example, of 80° to 130°C, preferably 90° to 120°C.
  • the temperature in the second reactor be at least 10°C higher, preferably 30° to 60°C higher than that in the first reactor.
  • the residence time of the catalyst in each reactor is controlled so that the productivity is suppressed in the first reactor and enhanced in the second reactor, consistent with the desired properties of the bimodal polymer product.
  • the residence time may be, for example, 0.5 to 6 hours, preferably 1 to 3 hours in the first reactor, and, for example, 1 to 12 hours, preferably 2.5 to 5 hours in the second reactor, with the ratio of residence time in the second reactor to that in the first reactor being in the range, for example, of 5 to 0.7, preferably 2 to 1.
  • the superficial gas velocity through both reactors is sufficiently high to disperse effectively the heat of reaction so as to prevent the temperature from rising to levels which could partially melt the polymer and shut the reactor down, and high enough to maintain the integrity of the fluidized beds.
  • Such gas velocity is in the range, for example, of 40 to 120, preferably 50 to 90 cm/sec.
  • the productivity of the process in the first reactor in terms of grams of polymer per gram atom of transition metal in the catalyst multiplied by 10 , may be in the range, for example, of 1.6 to 16.0, preferably 3.2 to 9.6; in the second reactor, the productivity may be in the range, for example, of 0.6 to 9.6, preferably 1.6 to 3.5, and in the overall process, the productivity is in the range, for example, of 2.2 to 25.6, preferably 4.8 to 16.0.
  • the foregoing ranges are based on analysis of residual catalyst metals in the resin product.
  • the polymer produced in the first reactor has a flow index (FI or I 21/ measured at 190°C in accordance with ASTM D-1238, Condition F) , for example, of 0.05 to 5, preferably 0.1 to 3 grams/10 min. and a density in the range, for example, of 0.890 to 0.960, preferably 0.900 to 0.940 grams/cc.
  • the polymer produced in the second reactor has a melt index (MI or I_, measured at 190°C in accordance with ASTM D- 1238, Condition E) in the range, for example, of 10 to 4000, preferably 15 to 2000 grams/10 min. and a density in the range, for example, of 0.890 to 0.976, preferably 0.930 to 0.976 grams/cc. These values are calculated based on a single reactor process model using steady state process data.
  • MI or I_ measured at 190°C in accordance with ASTM D- 1238, Condition E
  • the final granular bimodal polymer from the second reactor has a weight fraction of HMW polymer of at least 0.35, preferably in the range of 0.35 to 0.75, more preferably 0.45 to 0.65, a flow index in the range, for example, of 3 to 200, preferably 6 to 100 grams/10 min., a melt flow ratio (MFR, calculated as the ratio of flow index to melt index) in the range, for example, of 60 to 250, preferably 80 to 150, a density in the range, for example, of 0.89 to 0.965, preferably 0.910 to 0.960, an average particle size (APS) in the range, for example, of 127 to 1270, preferably 380 to 1100 microns, and a fines content (defined as particles which pass through a 120 mesh screen) of less than 10 wt.%, preferably less than 3 wt.%.
  • MFR melt flow ratio
  • APS average particle size
  • pellets When pellets are formed from granular resin which was stabilized and compounded with two passes on a Brabender extruder to ensure uniform blending, such pellets have a flow index in the range, for example, of 3 to 200, preferably 6 to 100 grams/10 min., a melt flow ratio in the range, for example, of 60 to 250, preferably 80 to 150, and a heterogeneity index (HI, the ratio of the FI's of the granular to the pelleted resin) in the range for example of 1.0 to 1.5, preferably 1.0 to 1.3. HI indicates the relative degree of inter-particle heterogeneity of the granular resin.
  • Ethylene/1-hexene copolymers were prepared with these catalysts under the same polymerization conditions.
  • a typical example is shown below.
  • a 1.6 liter stainless steel autoclave under a slow nitrogen purge at 50 C C was filled with 750 ml of dry hexane, 30 ml of dry 1-hexene, and 3.0 mmol of triethylaluminum.
  • the reactor was closed, the stirring was increased to 900 rpm, and the internal temperature was increased to 85°C.
  • the internal pressure was raised 12 psi with hydrogen. Ethylene was introduced to maintain the pressure at 120 psi.
  • the internal temperature was decreased to 80°C, 20.0 mg of catalyst was introduced into the reactor with ethylene over pressure, and the internal temperature was increased and held at 85°C.
  • the polymerization was continued for 60 minutes, and then the ethylene supply was stopped and the reactor was allowed to cool to room temperature.
  • the polyethylene was collected and air dried.

Abstract

Cette invention se rapporte à une composition de catalyseur de polymérisation d'α-oléfines sur support, qui possède une activité accrue mesurée en terme de productivité et qui est préparée selon un procédé à plusieurs étapes. On forme un catalyseur d'homopolymérisation d'éthylène ou de copolymérisation d'éthylène: (i) en prenant une boue d'un support inorganique poreux solide ayant des groupes hydroxyle (-OH) réactifs et un solvant non polaire; (ii) en imprégnant ce support contenant les groupes -OH avec un composé RMgR', afin de former un intermédiaire, lequel présente un rapport groupe -OH:Mg inférieur à 1, composé dans lequel chacun des éléments R et R' représente alkyle de 1 à 12 atomes de carbone et est identique ou différent; (iii) en traitant cet intermédiaire avec TiCl4, afin de former un intermédiaire contenant du titane, qui présente un rapport groupe -OH:Ti inférieur à 1; (iv) en faisant réagir cet intermédiaire contenant du titane avec une quantité d'un donneur d'électrons à teneur en oxygène, contenant 1 à 15 atomes de carbone et en combinant avec du triéthylaluminium cet intermédiaire contenant du titane traité avec un donneur d'électrons, afin de former ledit catalyseur. Ce catalyseur permet également de produire des polymères ayant une répartition relativement intermédiaire des poids moléculaires.
EP97932291A 1996-07-11 1997-06-25 Catalyseurs a forte activite pour la preparation de polyethylene avec une repartition intermediaire des poids moleculaires Withdrawn EP0910470A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US677163 1991-03-29
US67716396A 1996-07-11 1996-07-11
PCT/US1997/011078 WO1998002245A1 (fr) 1996-07-11 1997-06-25 Catalyseurs a forte activite pour la preparation de polyethylene avec une repartition intermediaire des poids moleculaires

Publications (2)

Publication Number Publication Date
EP0910470A1 true EP0910470A1 (fr) 1999-04-28
EP0910470A4 EP0910470A4 (fr) 2000-08-09

Family

ID=24717594

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97932291A Withdrawn EP0910470A4 (fr) 1996-07-11 1997-06-25 Catalyseurs a forte activite pour la preparation de polyethylene avec une repartition intermediaire des poids moleculaires

Country Status (7)

Country Link
EP (1) EP0910470A4 (fr)
JP (1) JP2000514492A (fr)
KR (1) KR20000023620A (fr)
AU (1) AU715831B2 (fr)
CA (1) CA2260026A1 (fr)
TW (1) TW494111B (fr)
WO (1) WO1998002245A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6399531B1 (en) 1999-12-28 2002-06-04 Union Carbide Chemicals & Plastics Technology Corporation Hybrid ziegler-natta and cycloalkadienyl catalysts for the production of polyolefins
US6444605B1 (en) 1999-12-28 2002-09-03 Union Carbide Chemicals & Plastics Technology Corporation Mixed metal alkoxide and cycloalkadienyl catalysts for the production of polyolefins
BR0309539A (pt) 2002-05-06 2005-03-01 Union Carbide Chem Plastic Composições de catalisadores misturados para a produção de poliolefinas e seu uso
EP1780225A1 (fr) * 2005-11-01 2007-05-02 Borealis Technology Oy Catalyseur Ziegler-Natta et son utilisation pour la preparation de polyolefines multimodales
WO2018091261A1 (fr) * 2016-11-17 2018-05-24 Basell Polyolefine Gmbh Composition de polyéthylène à taux de gonflement élevé
BR112019010107B1 (pt) * 2016-11-24 2022-11-01 Basell Polyolefine Gmbh Composição de polietileno para moldagem por sopro, artigos fabricados compreendendo a mesma e processo para sua preparação
RU2720235C1 (ru) * 2016-11-24 2020-04-28 Базелл Полиолефин Гмбх Полиэтиленовая композиция для выдувного формования с высокой стойкостью к растрескиванию под напряжением

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4301029A (en) * 1979-01-10 1981-11-17 Imperial Chemical Industries Limited Olefin polymerization catalyst and the production and use thereof
WO1994009041A1 (fr) * 1992-10-19 1994-04-28 Mobil Oil Corporation Catalyseurs de polyethylene fortement actifs

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0655780B2 (ja) * 1984-07-09 1994-07-27 東燃株式会社 オレフイン重合用触媒成分

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4301029A (en) * 1979-01-10 1981-11-17 Imperial Chemical Industries Limited Olefin polymerization catalyst and the production and use thereof
WO1994009041A1 (fr) * 1992-10-19 1994-04-28 Mobil Oil Corporation Catalyseurs de polyethylene fortement actifs

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9802245A1 *

Also Published As

Publication number Publication date
AU715831B2 (en) 2000-02-10
TW494111B (en) 2002-07-11
WO1998002245A1 (fr) 1998-01-22
JP2000514492A (ja) 2000-10-31
AU3578797A (en) 1998-02-09
CA2260026A1 (fr) 1998-01-22
KR20000023620A (ko) 2000-04-25
EP0910470A4 (fr) 2000-08-09

Similar Documents

Publication Publication Date Title
US5470812A (en) High activity polyethylene catalysts prepared with alkoxysilane reagents
AU677145B2 (en) Catalyst composition
US5561091A (en) High activity polyethylene catalyst prepared from an alcohol and silicon tetrachloride
AU723865B2 (en) Ziegler-natta catalyst for ethylene polymerization or copolymerization
US5260245A (en) High activity polyethylene catalysts
EP0324588A2 (fr) Composition de catalyseur pour la préparation de polymères d'alpha-oléfines à distribution de poids moléculaire étroite
JPH01308407A (ja) 分子量分布の狭いアルファオレフィンポリマー重合用触媒組成物
US5442018A (en) Ethylene polymerization using a titanium and vanadium catalyst system in staged reactors
US5939348A (en) Catalyst for the manufacture of polythylene with a narrow molecular weight distribution
AU715831B2 (en) High activity catalysts for the preparation of polyethylene with an intermediate molecular weight distribution
EP1052266A1 (fr) Catalyseur pour la polymérisation d'éthylène ayant une activité élevée
US5330951A (en) Catalyst composition for polymerizing alpha-olefin
EP0518604B1 (fr) Catalyseurs de polymérisation d'éthylène à haute activité, préparés à partir d'agent oxidant
US5093443A (en) Alpha-olefins polymerization with chlorinated alcohol-containing catalyst composition
US4954470A (en) Chlorinated alcohol-containing catalyst composition for polymerizing alpha-olefins
AU700892B2 (en) Catalyst for the manufacture of polyethylene with a narrow molecular weight distribution
EP0664815B1 (fr) Procede de preparation d'une compostion de catalyseur
US20030054944A1 (en) Catalyst for polyethylene giving an improved short chain branching distribution

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19990204

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): BE DE ES FR GB IT NL

A4 Supplementary search report drawn up and despatched

Effective date: 20000628

AK Designated contracting states

Kind code of ref document: A4

Designated state(s): BE DE ES FR GB IT NL

RIC1 Information provided on ipc code assigned before grant

Free format text: 7B 01J 31/26 A, 7B 01J 31/32 B, 7C 08F 10/00 B

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: EXXONMOBIL OIL CORPORATION

17Q First examination report despatched

Effective date: 20021004

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20040113