WO1999002573A1 - Procede de reduction de la formation de feuilles pendant la polymerisation d'olefines - Google Patents
Procede de reduction de la formation de feuilles pendant la polymerisation d'olefines Download PDFInfo
- Publication number
- WO1999002573A1 WO1999002573A1 PCT/US1998/013884 US9813884W WO9902573A1 WO 1999002573 A1 WO1999002573 A1 WO 1999002573A1 US 9813884 W US9813884 W US 9813884W WO 9902573 A1 WO9902573 A1 WO 9902573A1
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- reactor
- catalyst
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- polymerization
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
Definitions
- a relatively simple method of controlling static in a fluidized bed reactor is to feed a prostatic agent in ppm quantities to the reactor in order to neutralize the existing static voltage as taught in U.S. Patent No. 4,855,370 and U.S. Patent No. 4,803,251.
- HP-LDPE high pressure, low density polyethylene
- HP-LDPE's are characterized by an intricate long chain branched molecular architecture. These long chain branches have a dramatic effect on the melt rheology of these resins.
- HP-LDPE's also possess a spectrum of short chain branches, generally 1 to 6 carbon atoms in length. These short chain branches disrupt crystal formation and depress resin density.
- low pressure, high or low density polyethylene s, as well as other polymers can now be conventionally provided by a fluidized bed process utilizing several families of catalysts to produce a full range of low density and high density products.
- the appropriate selection of catalysts to be utilized depends in part upon the type of end product desired, i.e., high density, low density, extrusion grade, film grade resins and other criteria.
- the present invention provides a method for reducing sheeting during polymerization of olefins or diolefins in a fluidized bed reactor in the presence of a polymerization catalyst, optionally in the presence of an inert particulate material, which method comprises lowering the reactor bed temperature, optionally with the addition of a prostatic agent, by an amount sufficient to maintain the electrostatic levels at the site of potential sheet formation at levels which avoid sheeting without substantially altering the activity of said catalyst.
- the above- described method for reducing sheeting is employed in the polymerization of an ethylene-hexene copolymer in a gas phase fluidized bed reactor in the presence of a titanium-based catalyst such as a TiCl3 or TiCl4 catalyst.
- a titanium-based catalyst such as a TiCl3 or TiCl4 catalyst.
- copolymer has a density of about 0.915 to 0.932 g/cm , e.g., 0.925
- the ethylene-hexene copolymer is produced such that the feeds are 35-41% C2; 2-6% CQ; 5-8.1% H2 with the balance being made up of inerts (e.g., N2, isopentane and/or hexane).
- the normal temperature for this product is 90-92°C, but can be and is preferably polymerized at temperatures ranging from 75-92°C, most preferably 75-85°C to prevent or reduce sheeting.
- Figure 1 is a schematic depiction of a gas phase polymerization reactor and system.
- Figure 2 shows reactor transition from a first product (0.917 density; 1.0 MI) to a second product (0.925 density; 0.5 MI) of Example 1.
- Figure 3 demonstrates effectiveness of decreasing temperature to control/reduce static when employing a triethylaluminum cocatalyst.
- polymers Illustrative of the polymers which can be produced in accordance with the process of the invention are the following: homopolymers and copolymers of C2-C18 alpha olefins, preferably homo- and co-polymers of ethylene and a C3-C8 alpha olefin; ethylene propylene rubbers (EPRs); ethylene-propylene diene rubbers (EPDMs); polyisoprene; polystyrene; polybutadiene; polymers of butadiene copolymerized with styrene; polymers of butadiene copolymerized with isoprene; polymers of butadiene copolymerized with acrylonitrile; polymers of isobutylene copolymerized with isoprene; ethylene butene rubbers and ethylene butene diene rubbers; polychloroprene; norbornene homopolymers and copolymers with one or more C2-C18 al
- the preferred polymers to which the present invention is primarily directed, and which cause the sheeting problems referred to above, are those produced using a titanium catalyst.
- Such preferred polymers can include, for example, linear homopolymers of ethylene or linear copolymers of a major mol percent (greater than or equal to 80%) of ethylene, and a minor mol percent (less than or equal to 20%) of one or more C3 to Cg alpha olefins.
- the C3 to Cs alpha olefins should not contain any branching on any of their carbon atoms which is closer than the fourth carbon atom.
- the C3 to Cg alpha olefins are present in amounts ranging from 1% to 20%, most preferably from 1% to 12%.
- the preferred C3 to CQ alpha olefins are propylene, butene- 1, pentene-1, hexene-1, 4-methylpentene-l, heptene- 1, and octene-1.
- the most preferred C3 to Cg alpha olefin for use in an ethylene copolymer is hexene-1.
- These homopolymers and copolymers have a density ranging from about 0.84 to 0.97, preferably from about 0.88 to 0.94.
- the density of the copolymer, at a given melt index level, is primarily regulated by the amount of the C3 to Cg comonomer which is copolymerized with the ethylene.
- the amount of each of the various C3 to Cg comonomers needed to achieve the same result will vary from monomer to monomer, under the same reaction conditions. In the absence of the comonomer, the ethylene would homopolymerize. This description is not intended to exclude the use of this invention with alpha olefin homopolymer and copolymer resins in which ethylene is not a monomer.
- the melt index of a homopolymer or copolymer is a reflection of its molecular weight. Polymers having a relatively high molecular weight, have relatively high viscosities and low melt index.
- Ziegler-Natta catalysts including titanium based catalysts such as those described in U.S. Patent Nos. 4,302,566; 4,376,062; and 4,379,758.
- Ziegler-Natta catalysts are well known in the art, and typically are magnesium/titanium/electron donor complexes used in conjunction with an organoaluminum cocatalyst.
- Vanadium based catalysts such as vanadium oxychloride and vanadium acetylacetonate, such as described in U.S. Patent No. 5,317,036.
- Nickel catalysts and mixtures thereof such as those described in U.S. Patent Nos. 4,155,880 and 4,102,817; PCT Application Nos. 95/109826 and 95/09827.
- the preferred catalysts for the process of the present invention include rare earth metal catalysts, titanium catalysts, vanadium catalysts, and the metallocene/single-site/single- site-like catalysts.
- titanium catalysts and metallocenes or other single-site or single-site like catalysts or catalyst complexes containing titanium and their polymerizations can especially benefit from the present invention.
- the titanium compound has the structure: Ti(OR) a X D) wherein R is a C to C14 aliphatic or aromatic hydrocarbon radical, or COR' where R' is a C to C14 aliphatic or aromatic hydrocarbon radical; X is Cl, Br, or I; a is 0 or 1; b is 2 to 4 inclusive; and a+b equals 3 or 4.
- the catalyst may be modified with a boron halide compound having the structure: BR C X'3_ C) wherein R is an aliphatic or aromatic hydrocarbon radical containing from 1 to 14 carbon atoms or OR', wherein R' is also an aliphatic or aromatic hydrocarbon radical containing from 1 to 14 carbon atoms; X' is selected from the group consisting of Cl and Br, or mixtures thereof; and c is 0 or 1 when R is an aliphatic or aromatic hydrocarbon and c is 0, 1 or 2 when R is OR'.
- R is an aliphatic or aromatic hydrocarbon radical containing from 1 to 14 carbon atoms or OR'
- R' is also an aliphatic or aromatic hydrocarbon radical containing from 1 to 14 carbon atoms
- X' is selected from the group consisting of Cl and Br, or mixtures thereof
- c is 0 or 1 when R is an aliphatic or aromatic hydrocarbon and c is 0, 1 or 2 when R is OR'.
- the carrier materials of this particular titanium catalyst system are solid, particulate materials and include inorganic materials such as oxides of silicon and aluminum and molecular sieves, and organic materials such as olefin polymers, e.g., polyethylene.
- the process of the present invention is most effective when used in alpha olefin polymerizations utilizing these titanium catalysts, especially supported titanium catalysts. Titanium catalysts on a silica support are most preferred.
- fluidization aids employed in the invention can be inert particulate materials which are chemically inert to the reaction.
- fluidization aids include carbon black, silica, clays, other like materials such'as talc, and mixtures thereof.
- Organic polymeric materials can also be employed as a fluidization aid. Carbon blacks, silica, and mixtures of them are the preferred fluidization aids with carbon black being the most preferred.
- the carbon black materials employed have a primary particle size of about 10 to 100 nanometers and an average size of aggregate (primary structure) of about 0.1 to about 10 microns.
- the specific surface area of the carbon black is about 30 to 1,500 m2/gm and the carbon black displays a dibutylphthalate (DBP) absorption of about 80 to about 350 cc/100 grams.
- DBP dibutylphthalate
- Silicas which can be employed are amorphous and have a primary particle size of about 5 to 50 nanometers and an average size of aggregate of about 0.1 to 10 microns.
- the average size of agglomerates of silica is about 2 to about 120 microns.
- the silicas employed have a specific surface area of about 50 to 500 m2/gm and a dibutylphthalate (DBP) absorption of about 100 to 400 cc/100 grams.
- DBP dibutylphthalate
- the amount of fluidization aid utilized generally depends on the type of material utilized and polymer produced. When utilizing carbon black or silica, or preferably a mixture of the two, as the fluidization aid, they can be employed in amounts of about 0.3% to about 80% by weight, preferably about 5% to about 60%, and most preferably about 10% to about 45%, based on the weight of the final product (polybutadiene or polyisoprene) produced. When clays or talcs are employed as the fluidization aid, the amount can range from about 0.3% to about 80% based on the weight of the final product, preferably about 12% to 75% by weight. Organic polymeric materials are used in amounts of about 0.1% to about 50% by weight, preferably about 0.1% to about 10% based on the weight of the final polymer product produced.
- the polymerization conditions in the gas phase reactor are such that the temperature ranges from about 0° to 120°C, preferably about 40° to 110°C, and most preferably about 70° to 90°C.
- Partial pressure will vary depending upon the particular monomer employed and the temperature of the polymerization, and it can range from about 1 to 150 psi. Condensation temperatures of the monomers are well known.
- the ethylene partial pressure ranges from about 80 to 120 psia. In general, it is preferred to operate at a partial pressure slightly above to slightly below the dew point of the monomer (that is, for example, + 10°C for low boiling monomers).
- static voltage in the reactor is monitored near the reactor wall by one or more static voltage indicators such as static probe (50) inserted into the reactor bed, preferably approximately 5 feet above the gas distribution plate.
- static probe 50
- the voltage range of the indicators is in the range of about +15,000 volts.
- catalyst activity is not altered significantly by lowering the temperature and/or the washing effect (which occurs in less than 4% of the total bed volume) because the catalyst kinetics are such that the loss of activity is less than 10%.
- Any gas inert to the catalyst and reactants can also be present in the gas stream.
- the cocatalyst is added to the gas recycle stream upstream of its connection with the reactor as from dispenser (28) through line (30).
- the appropriate catalyst used in the fluidized bed is preferably stored for service in a reservoir (16) under a blanket of a gas which is inert to the stored material, such as nitrogen or argon.
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polymerisation Methods In General (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
L'invention concerne un procédé de réduction de la formation de feuilles pendant la polymérisation d'une ou plusieurs oléfines, notamment des dioléfines, dans un réacteur à lit fluidisé, en présence d'un catalyseur de polymérisation et éventuellement d'une substance particulaire inerte. Ce procédé consiste à baisser le niveau de la température du lit, éventuellement par ajout d'un agent conducteur d'électricité statique, cet agent étant en quantité suffisante pour maintenir les niveaux électrostatiques sur le site de formation potentielle de feuilles, permettant ainsi d'éviter la formation de feuilles sans altérer sensiblement l'activité dudit catalyseur.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU83826/98A AU8382698A (en) | 1997-07-08 | 1998-07-07 | Method for reducing sheeting during olefin polymerization |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US88961797A | 1997-07-08 | 1997-07-08 | |
US08/889,617 | 1997-07-08 |
Publications (1)
Publication Number | Publication Date |
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WO1999002573A1 true WO1999002573A1 (fr) | 1999-01-21 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/013884 WO1999002573A1 (fr) | 1997-07-08 | 1998-07-07 | Procede de reduction de la formation de feuilles pendant la polymerisation d'olefines |
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AU (1) | AU8382698A (fr) |
WO (1) | WO1999002573A1 (fr) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000058371A1 (fr) * | 1999-03-30 | 2000-10-05 | Eastman Chemical Company | Procede de production de polyolefines |
WO2001066610A1 (fr) * | 2000-03-06 | 2001-09-13 | Bp Chemicals Limited | Procede de reduction de la mise en nappe ou en agglomerats au cours de la polymerisation d'olefine |
AU2001247683B2 (en) * | 2000-03-27 | 2006-01-12 | Bristol-Myers Squibb Company | Synergistic methods and compositions for treating cancer |
US7598327B2 (en) | 2004-11-10 | 2009-10-06 | Chevron Phillips Chemical Company Lp | Method for polymerizing olefins in a gas phase reactor using a seedbed during start-up |
US8433443B2 (en) | 2007-02-16 | 2013-04-30 | Univation Technologies, Llc | Method for on-line monitoring and control of polymerization processes and reactors to prevent discontinuity events |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4035560A (en) * | 1975-05-27 | 1977-07-12 | Naphtachimie | Method of polymerizing olefins in a fluidized bed |
US4855370A (en) * | 1986-10-01 | 1989-08-08 | Union Carbide Corporation | Method for reducing sheeting during polymerization of alpha-olefins |
US4994534A (en) * | 1989-09-28 | 1991-02-19 | Union Carbide Chemicals And Plastics Company Inc. | Process for producing sticky polymers |
US5352749A (en) * | 1992-03-19 | 1994-10-04 | Exxon Chemical Patents, Inc. | Process for polymerizing monomers in fluidized beds |
WO1994025497A1 (fr) * | 1993-04-26 | 1994-11-10 | Exxon Chemical Patents Inc. | Procede de polymerisation de monomeres dans des lits fluidifies |
US5453471A (en) * | 1994-08-02 | 1995-09-26 | Union Carbide Chemicals & Plastics Technology Corporation | Gas phase polymerization process |
US5462999A (en) * | 1993-04-26 | 1995-10-31 | Exxon Chemical Patents Inc. | Process for polymerizing monomers in fluidized beds |
-
1998
- 1998-07-07 WO PCT/US1998/013884 patent/WO1999002573A1/fr active Application Filing
- 1998-07-07 AU AU83826/98A patent/AU8382698A/en not_active Abandoned
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4035560A (en) * | 1975-05-27 | 1977-07-12 | Naphtachimie | Method of polymerizing olefins in a fluidized bed |
US4855370A (en) * | 1986-10-01 | 1989-08-08 | Union Carbide Corporation | Method for reducing sheeting during polymerization of alpha-olefins |
US4994534A (en) * | 1989-09-28 | 1991-02-19 | Union Carbide Chemicals And Plastics Company Inc. | Process for producing sticky polymers |
US5352749A (en) * | 1992-03-19 | 1994-10-04 | Exxon Chemical Patents, Inc. | Process for polymerizing monomers in fluidized beds |
WO1994025497A1 (fr) * | 1993-04-26 | 1994-11-10 | Exxon Chemical Patents Inc. | Procede de polymerisation de monomeres dans des lits fluidifies |
US5462999A (en) * | 1993-04-26 | 1995-10-31 | Exxon Chemical Patents Inc. | Process for polymerizing monomers in fluidized beds |
US5453471A (en) * | 1994-08-02 | 1995-09-26 | Union Carbide Chemicals & Plastics Technology Corporation | Gas phase polymerization process |
US5453471B1 (en) * | 1994-08-02 | 1999-02-09 | Carbide Chemicals & Plastics T | Gas phase polymerization process |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000058371A1 (fr) * | 1999-03-30 | 2000-10-05 | Eastman Chemical Company | Procede de production de polyolefines |
US6300432B1 (en) | 1999-03-30 | 2001-10-09 | Eastman Chemical Company | Process for producing polyolefins |
WO2001066610A1 (fr) * | 2000-03-06 | 2001-09-13 | Bp Chemicals Limited | Procede de reduction de la mise en nappe ou en agglomerats au cours de la polymerisation d'olefine |
EP1688444A2 (fr) | 2000-03-06 | 2006-08-09 | Innovene Europe Limited | Procédé pour réduire la formation de feuilles et d' agglomérations pendant la polymérisation d'oléfines |
EP1688444A3 (fr) * | 2000-03-06 | 2009-03-18 | Ineos Europe Limited | Procédé pour réduire la formation de feuilles et d' agglomérations pendant la polymérisation d'oléfines |
US7812103B2 (en) | 2000-03-06 | 2010-10-12 | Ineos Europe Limited | Method for reducing sheeting and agglomerates during olefin polymerisation |
AU2001247683B2 (en) * | 2000-03-27 | 2006-01-12 | Bristol-Myers Squibb Company | Synergistic methods and compositions for treating cancer |
US7598327B2 (en) | 2004-11-10 | 2009-10-06 | Chevron Phillips Chemical Company Lp | Method for polymerizing olefins in a gas phase reactor using a seedbed during start-up |
US8433443B2 (en) | 2007-02-16 | 2013-04-30 | Univation Technologies, Llc | Method for on-line monitoring and control of polymerization processes and reactors to prevent discontinuity events |
Also Published As
Publication number | Publication date |
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AU8382698A (en) | 1999-02-08 |
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