WO2012119956A1 - Procédé de préparation de produits de polyéthylène pastillés - Google Patents

Procédé de préparation de produits de polyéthylène pastillés Download PDF

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WO2012119956A1
WO2012119956A1 PCT/EP2012/053661 EP2012053661W WO2012119956A1 WO 2012119956 A1 WO2012119956 A1 WO 2012119956A1 EP 2012053661 W EP2012053661 W EP 2012053661W WO 2012119956 A1 WO2012119956 A1 WO 2012119956A1
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pelleted
polyethylene
polyethylene resin
weight
product
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PCT/EP2012/053661
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English (en)
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Peter Stevens
Daan Dewachter
Etienne Laurent
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Total Research & Technology Feluy
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Publication of WO2012119956A1 publication Critical patent/WO2012119956A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/20—Compounding polymers with additives, e.g. colouring
    • C08J3/22—Compounding polymers with additives, e.g. colouring using masterbatch techniques
    • C08J3/226—Compounding polymers with additives, e.g. colouring using masterbatch techniques using a polymer as a carrier
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B9/00—Making granules
    • B29B9/12—Making granules characterised by structure or composition
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/005—Processes for mixing polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/06—Polyethene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • B29K2023/0608—PE, i.e. polyethylene characterised by its density
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2314/00—Polymer mixtures characterised by way of preparation
    • C08L2314/02—Ziegler natta catalyst
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2314/00—Polymer mixtures characterised by way of preparation
    • C08L2314/04—Philipps catalyst
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2314/00—Polymer mixtures characterised by way of preparation
    • C08L2314/06—Metallocene or single site catalysts

Definitions

  • the present invention relates to a method for preparing a pelleted polyethylene product and to the use of pelleted polyethylene.
  • the invention can advantageously be used in chemical manufacturing, specifically in the polymerization of olefins.
  • Polyethylene can be classified into several types, such as but not limited to LDPE (Low Density Polyethylene), LLDPE (Linear Low Density Polyethylene), and HDPE (High Density Polyethylene) as well as High Molecular Weight (HMW), Medium Molecular Weight (MMW) and Low Molecular Weight (LMW). Each type of polyethylene has different properties and characteristics.
  • Olefin (such as ethylene) polymerizations are frequently carried out in a loop reactor using monomer (such as ethylene), diluent and catalyst, optionally an activating agent, optionally one or more co-monomer(s), and optionally hydrogen.
  • Polymerization in a loop reactor is usually performed under slurry conditions, with the produced polymer usually in a form of solid particles suspended in diluent.
  • the slurry is circulated continuously in the reactor with a pump to maintain efficient suspension of the polymer solid particles in the liquid diluent.
  • Polymer slurry is discharged from the loop reactor by means of settling legs, which operate on a batch principle to recover the slurry. Settling in the legs is used to increase the solid concentration of the slurry finally recovered as product slurry.
  • the product slurry is further discharged through heated flash lines to a flash tank, where most of the diluent and unreacted monomers are flashed off and recycled.
  • the polymer product is collected from the reactor and the hydrocarbon residues are removed, the polymer product is dried resulting in a polymer resin. Additives can be added and finally the polymer may be mixed and pelletized resulting in polymer product.
  • polymer resin and optional additives are mixed intimately in order to obtain a polymer product as homogeneous as possible.
  • mixing is done in an extruder wherein the ingredients are mixed together and the polymer product and optionally some of the additives are melted so that intimate mixing can occur.
  • the melt is then extruded into a rod, cooled and granulated, e.g. to form pellets.
  • the resulting compound can then be used for the manufacturing of different objects.
  • two or more different polyethylene resins are produced separately and subsequently mixed, representing a physical blending process.
  • the present invention relates to a method of preparing a pelleted polyethylene product by:
  • step (iv) physically blending 1 % to 35% by weight of the pelleted first polyethylene resin with the polyethylene of step (iii) to produce the pelleted polyethylene product, preferably physically blending 3 to 20% by weight, more preferably 3.5 to 10% by weight of the pelleted first polyethylene resin with the polyethylene of step (iii) to produce the pelleted polyethylene product.
  • the present invention relates to a method of preparing a pelleted polyethylene product by:
  • step (iv) physically blending 1 % to 35% by weight of the pelleted first polyethylene resin with the polyethylene of step (iii) to produce the pelleted polyethylene product, with % by weight being based on the total weight of the pelleted polyethylene product.
  • the pelleted first polyethylene resin can be used for convenient adjustment of the properties of second polyethylene resin, allowing for flexible yet precise processing conditions, while producing homogeneous and high-quality end-products.
  • the present invention also relates to the use of pelleted polyethylene resin comprising a first polyethylene resin prepared in the presence of a metallocene catalyst, having a density of from 0.940 to 0.970 g/cm 3 , and at least one additive selected from pigments, UV-stabilizers, anti-oxidants, fillers, anti-static agents, for preparing a physical blend comprising from 1 % to 35% by weight of said pelleted polyethylene resin and a second polyethylene resin prepared in the presence of a Ziegler-Natta or Chromium catalyst.
  • a metallocene catalyst having a density of from 0.940 to 0.970 g/cm 3
  • at least one additive selected from pigments, UV-stabilizers, anti-oxidants, fillers, anti-static agents for preparing a physical blend comprising from 1 % to 35% by weight of said pelleted polyethylene resin and a second polyethylene resin prepared in the presence of a Ziegler-Natta or Chromium catalyst.
  • the present invention relates to a method of preparing a pelleted polyethylene product by physical blending (a) from 1 % to 35% by weight of a pelleted first polyethylene resin based on the total weight of the pelleted polyethylene product, with (b) a second polyethylene resin produced in the presence of a Ziegler-Natta and/or chromium catalyst, wherein said pelleted first polyethylene resin comprises a first polyethylene resin prepared in the presence of a metallocene catalyst, having a density of from 0.940 to 0.970 g/cm 3 , and at least one additive selected from pigments, UV-stabilizers, anti- oxidants, fillers, anti-static agents.
  • the present inventors have found that using from 1 % to 35% by weight of the first polyethylene resin in pelleted form may advantageously improve the properties of a second polyethylene resin produced in the presence of a Ziegler-Natta and/or chromium catalyst.
  • the pelleted first polyethylene resin may be chosen as a function of a fraction of the second polyethylene that is judged to be missing.
  • a pelleted first polyethylene resin with LMW is preferably added.
  • a pelleted first polyethylene resin with HMW is preferably added.
  • the pelleted first polyethylene resin may be chosen as a function of the density of one or more fractions of the second polyethylene.
  • the pelleted first polyethylene resin may for instance be chosen as a function of the difference in the average MFI and/or the average density between the HMW and the LMW fractions of the second polyethylene.
  • the process preferably comprises producing a first polyethylene resin having a density of from 0.940 to 0.970 g/cm 3 in the presence of a metallocene catalyst in step (i).
  • a metallocene catalyst in step (i).
  • said first metallocene produced polyethylene resin has a density of 0.950 to 0.965 g/cm 3 .
  • resin is defined as the polymer material that is produced in the loop reactor with the hard catalyst particle at the core of each grain of the powder and which is also sometimes referred to as "fluff".
  • polyethylene product or “polyethylene pellet” is defined as ethylene polymer material that is produced through compounding and homogenizing of the resin, for instance with mixing and/or extruder equipment.
  • the first polyethylene resin of step (i) is subsequently extruded in step (ii) with at least one additive into a pelleted first polyethylene resin.
  • a pelleted form of the first polyethylene resin is preferred as it allows for easy storage, for convenient adjustment of the properties of second polyethylene resin, for flexible yet precise processing conditions, and for production of homogeneous and high-quality end-products.
  • the present inventors have found that incorporating higher levels of additives in the first polyethylene that is in a pelleted form is particularly useful when adjusting the properties of the pelleted polyethylene product obtained in step (iv) of the invention. For instance, it may not be required anymore to add these additives in step (vi), providing additional processing flexibility, particularly in the case of pigment which might for instance otherwise stain processing equipment.
  • the additive is selected from pigments, UV-stabilizers, anti-oxidants, fillers, anti-static agents, dispersive aid agents, processing aids, anti-acid agents, and mixtures thereof.
  • the pelleted first polyethylene resin is extruded with a pigment.
  • Preferred levels of additives are from 2 to 60% by weight of the pelleted first polyethylene resin.
  • the pelleted first polyethylene resin comprises pigment at a level of at least 2,5% by weight, more preferably at least 2,6 % by weight and preferably at most 55% by weight, preferably at most 50% by weight, preferably at most 46 % by weight, based on the weight of the pelleted first polyethylene resin.
  • the polyethylene resin of step (iii) (second polyethylene resin) is separately produced in the presence of a Ziegler-Natta and/or chromium catalyst. More preferably, the polyethylene resin of step (iii) (second polyethylene resin) is separately produced in the presence of a Ziegler-Natta catalyst.
  • step (iii) produces a resin of the second polyethylene that is used in extrusion step (iv) of the invention.
  • the resin of the second polyethylene is preferably first extruded into a pelleted second polyethylene product before the extrusion step (iv) with the pelleted first polyethylene resin.
  • the pelleted polyethylene product is prepared in step (iv) by physical blending and melting 1 % to 35% by weight of the pelleted first polyethylene resin of step (ii) with the second polyethylene resin of step (iii).
  • step (ii) and/or step (iv) are performed in device for continuously melting and blending.
  • physical blending takes place in a device for continuously melting and blending said resins selected from a mixer, an extruder or combinations thereof.
  • the device can be an extruder and/or a mixer.
  • the device is an extruder.
  • a preferred extruder is a co-rotating twin screw.
  • a preferred mixer is a counter-rotating twin screw.
  • the final polyethylene product comprises from 1 to 35% by weight of the pelleted first polyethylene resin, more preferably from 2% to 30% by weight, most preferably from 2% to 28% by weight and preferably from 3% to 25% by weight, more preferably from 3% to 20% by weight and most preferably from 3.5% to 15% by weight of the pelleted first polyethylene resin.
  • the polyethylene product comprises at most 99% by weight of the second polyethylene resin, more preferably at most 98% by weight, more preferably at most 97.5% by weight, and preferably at most 97% by weight, and preferably at most 95% by weight, more preferably at most 90% by weight.
  • the polyethylene product of the invention has a multimodal molecular weight distribution.
  • the pelleted first polyethylene resin of step ii) has a monomodal molecular weight distribution.
  • the present inventors have surprisingly found that physically blending a monomodal pelleted first polyethylene resin with the polyethylene of step (iii) leads to a homogeneous polyethylene product with optimal characteristics under acceptable processing conditions.
  • the second polyethylene resin has a monomodal or bimodal molecular weight distribution. More preferably, the second polyethylene resin has a bimodal molecular weight distribution.
  • polymers with a monomodal molecular weight distribution polymers having one maxima in their molecular weight distribution curve defined also as unimodal distribution curve.
  • polymers with a bimodal molecular weight distribution or “bimodal polymers” it is meant, polymers having a distribution curve being the sum of two unimodal molecular weight distribution curves.
  • polymers with a multimodal molecular weight distribution or “multimodal” polymers it is meant polymers with a distribution curve being the sum of at least two, preferably more than two unimodal distribution curves.
  • polyethylene with a monomodal molecular weight distribution polyethylene having one maxima in their molecular weight distribution curve defined also as unimodal distribution curve.
  • polyethylene with a multimodal molecular weight distribution or “multimodal” polyethylene product it is meant polyethylene with a distribution curve being the sum of at least two, preferably more than two unimodal distribution curves.
  • the pelleted polyethylene product has a High Load Melt Index (HLMI) of from 2 to 50 g/10min, preferably from 5 to 20g/10min.
  • HLMI High Load Melt Index
  • the pelleted polyethylene product has a density of from 0.930 to 0.965g/cm 3 as measured with the ASTM D-1505 standardized test at a temperature of 23°C.
  • the HLMI is determined with the ASTM D-1238 standardized test which uses a temperature of 190°C and a load of 21.6 kg.
  • the density is determined with the ASTM D-1505 standardized test at a temperature of 23°C.
  • the pelleted polyethylene product of the invention is especially useful in pipe applications.
  • the present invention relates to the use of pelleted polyethylene produced in the presence of metallocene and comprising a first polyethylene resin prepared in the presence of a metallocene catalyst, having a density of from 0.940 to 0.970 g/cm 3 , and at least one additive selected from pigments, UV-stabilizers, anti- oxidants, fillers, anti-static agents, for preparing a physical blend comprising from 1 % to 35% by weight of said pelleted polyethylene and a second polyethylene resin prepared in the presence of a Ziegler-Natta or Chromium catalyst.
  • the pelleted polyethylene and the polyethylene resin are subsequently physically blended, more preferably extruded, to produce a pelleted final polyethylene product.
  • the present invention relates to the use of pelleted polyethylene resin comprising a first polyethylene resin prepared in the presence of a metallocene catalyst, having a density of from 0.940 to 0.970 g/cm 3 as measured with ASTM D-1505 standardized test at a temperature of 23°C, and at least one additive selected from pigments, UV-stabilizers, anti-oxidants, fillers, anti-static agents, for preparing a physical blend comprising from 1 % to 35% by weight of said pelleted polyethylene resin and a second polyethylene resin prepared in the presence of a Ziegler- Natta or Chromium catalyst, with % by weight being based on the total weight of the pelleted polyethylene product.
  • a metallocene catalyst having a density of from 0.940 to 0.970 g/cm 3 as measured with ASTM D-1505 standardized test at a temperature of 23°C
  • at least one additive selected from pigments, UV-stabilizers, anti-oxidants, fillers, anti-static agents
  • Polyolefin, and in particular polyethylene, resins are preferably prepared in a loop reactor that preferably comprises interconnected pipes, defining a reactor path, and wherein a slurry is preferably pumped through said loop reactor.
  • a loop reactor that preferably comprises interconnected pipes, defining a reactor path, and wherein a slurry is preferably pumped through said loop reactor.
  • each of the polyethylene resins of the invention is separately produced.
  • polymerization slurry or “polymer slurry” or “slurry” means substantially a multi-phase composition including at least polymer solids and a liquid phase, the liquid phase being the continuous phase.
  • the solids include catalyst and a polymerized olefin, such as polyethylene.
  • the liquids include an inert diluent, such as isobutane, dissolved monomer such as ethylene, co-monomer, molecular weight control agents, such as hydrogen, antistatic agents, antifouling agents, scavengers, and other process additives.
  • catalyst refers to a substance that causes a change in the rate of a polymerization reaction without itself being consumed in the reaction.
  • it is especially applicable to catalysts suitable for the polymerization of ethylene to polyethylene. These catalysts will be referred to as ethylene polymerization catalysts or polymerization catalysts.
  • the invention is suitable for supported heterogeneous catalysts. In the present invention it is especially applicable to ethylene polymerization catalysts such as metallocene catalysts, Ziegler-Natta catalysts and chromium catalysts.
  • metallocene catalyst is used herein to describe any transition metal complexes consisting of metal atoms bonded to one or more ligands.
  • the metallocene catalysts are compounds of Group IV transition metals of the Periodic Table such as titanium, zirconium, hafnium, etc., and have a coordinated structure with a metal compound and ligands composed of one or two groups of cyclopentadienyl, indenyl, fluorenyl or their derivatives.
  • Use of metallocene catalysts in the polymerization of olefins has various advantages. Metallocene catalysts have high activities and are capable of preparing polymers with enhanced physical properties. The key to metallocenes is the structure of the complex.
  • Metallocenes can be varied to adapt to the specific need of the producer depending on the desired polymer.
  • Metallocenes comprise a single metal site, which allows for more control of branching and molecular weight distribution of the polymer. Monomers are inserted between the metal and the growing chain of polymer.
  • the metallocene catalyst has a general formula (I) or (II):
  • metallocenes according to formula (I) are non-bridged metallocenes and the metallocenes according to formula (II) are bridged metallocenes;
  • metallocene according to formula (I) or (II) has two Ar bound to M which can be the same or different from each other;
  • Ar is an aromatic ring, group or moiety and wherein each Ar is independently selected from the group consisting of cyclopentadienyl, indenyl (IND), tetrahydroindenyl (THI) or fluorenyl, wherein each of said groups may be optionally substituted with one or more substituents each independently selected from the group consisting of halogen, a hydrosilyl, a SiR 3 group wherein R is a hydrocarbyl having 1 to 20 carbon atoms, and a hydrocarbyl having 1 to 20 carbon atoms, and wherein said hydrocarbyl optionally contains one or more atoms selected from the group comprising B, Si, S, O, F, CI and P; wherein M is a transition metal selected from the group consisting of titanium, zirconium, hafnium and vanadium; and preferably is zirconium;
  • each Q is independently selected from the group consisting of halogen; a hydrocarboxy having 1 to 20 carbon atoms; and a hydrocarbyl having 1 to 20 carbon atoms and wherein said hydrocarbyl optionally contains one or more atoms selected from the group comprising B, Si, S, O, F, CI and P; and
  • R" is a divalent group or moiety bridging the two Ar groups and selected from the group consisting of a C C 20 alkylene, a germanium, a silicon, a siloxane, an alkylphosphine and an amine, and wherein said R" is optionally substituted with one or more substituents each independently selected from the group consisting of halogen, a hydrosilyl, a SiR 3 group wherein R is a hydrocarbyl having 1 to 20 carbon atoms, and a hydrocarbyl having 1 to 20 carbon atoms and wherein said hydrocarbyl optionally contains one or more atoms selected from the group comprising B, Si, S, O, F, CI and P.
  • hydrocarbyl having 1 to 20 carbon atoms as used herein is intended to refer to a moiety selected from the group comprising a linear or branched C C 20 alkyl; C 3 -C 2 o cycloalkyl; C 6 -C 2 o aryl; C 7 -C 20 alkylaryl and C 7 -C 20 arylalkyl, or any combinations thereof.
  • Exemplary hydrocarbyl groups are methyl, ethyl, propyl, butyl, amyl, isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl, 2-ethylhexyl, and phenyl.
  • Exemplary halogen atoms include chlorine, bromine, fluorine and iodine and of these halogen atoms, fluorine and chlorine are preferred.
  • Exemplary of the alkylene groups is methylidene, ethylidene and propylidene.
  • metallocene catalysts comprise but are not limited to bis(cyclopentadienyl) zirconium dichloride (Cp 2 ZrCI 2 ), bis(cyclopentadienyl) titanium dichloride (Cp 2 TiCI 2 ), bis(cyclopentadienyl) hafnium dichloride (Cp 2 HfCI 2 ); bis(tetrahydroindenyl) zirconium dichloride, bis(indenyl) zirconium dichloride, and bis(n- butyl-cyclopentadienyl) zirconium dichloride; ethylenebis(4,5,6,7-tetrahydro-1-indenyl) zirconium dichloride, ethylenebis(l-indenyl) zirconium dichloride, dimethylsilylene bis(2- methyl-4-phenyl-inden-1-yl) zirconium dichloride, diphenylmethylene (cyclopentadienyl)(
  • the metallocene catalysts generally are provided on a solid support.
  • the support should be an inert solid, which is chemically unreactive with any of the components of the conventional metallocene catalyst.
  • the support is preferably a silica compound.
  • the metallocene catalyst is provided on a solid support, preferably a silica support.
  • Ziegler-Natta catalyst refers to catalysts preferably of the a general formula M 1 X V , wherein M 1 is a transition metal compound selected from group IV to VII, wherein X is a halogen, and wherein v is the valence of the metal.
  • M 1 is a group IV, group V or group VI metal, more preferably titanium, chromium or vanadium and most preferably titanium.
  • X is chlorine or bromine, and most preferably, chlorine.
  • Illustrative examples of the transition metal compounds comprise but are not limited to TiCI 3 , TiCI 4 . Suitable ZN catalysts for use in the invention are described in US6930071 and US6864207, which are incorporated herein by reference.
  • the first polyethylene resin is produced in the presence of a Ziegler-Natta catalyst with an average particle size (D50) of at most 50 ⁇ , preferably, at most 30 ⁇ , more preferably at most 15 ⁇ , more preferably at most 13 ⁇ , most preferably at most 10 ⁇ , most preferably at most 8 ⁇ , for example at most 5 ⁇ and preferably at least 3 ⁇ .
  • D50 average particle size
  • the D50 is defined as the particle size for which fifty percent by volume of the particles has a size lower than the D50.
  • the measurement of the average particle size (D50) can be made according to the International Standard ISO 13320:2009 ("Particle size analysis - Laser diffraction methods").
  • ISO 13320:2009 Particle size analysis - Laser diffraction methods
  • Malvern Instruments' laser diffraction systems can advantageously be used.
  • the D50 can be measured by laser diffraction analysis on a Malvern type analyzer after having put the supported catalyst in suspension in cyclohexane.
  • Suitable Malvern systems include the Malvern 2000, Malvern MasterSizer (such as Mastersizer S), Malvern 2600 and Malvern 3600 series. Such instruments together with their operating manual meets or even exceeds the requirements set-out within the ISO 13320 Standard.
  • the Malvern MasterSizer (such as Mastersizer S) may also be useful as it can more accurately measure the D50 towards the lower end of the range e.g
  • Suitable Ziegler Natta catalysts of average particle size (D50) of at most 15 ⁇ are commercially available from W. R. Grace and Company, such as SYLOPOL®5910 which has an average particle size of 10 ⁇ , or from Lyondellbasell.
  • chromium catalysts refers to catalysts obtained by deposition of chromium oxide on a support, e.g. a silica or aluminium support.
  • Illustrative examples of chromium catalysts comprise but are not limited to CrSi0 2 or CrAI 2 0 3 .
  • the catalyst is preferably added to the loop reactor as a catalyst slurry.
  • catalyst slurry refers to a composition comprising catalyst solid particles and a diluent.
  • the solid particles can be suspended in the diluent, either spontaneously or by homogenization techniques, such as mixing.
  • the solid particles can be non- homogeneously distributed in a diluent and form a sediment or deposit.
  • activating agent is used in processes according to the invention.
  • activating agent refers to materials that can be used in conjunction with a catalyst in order to improve the activity of the catalyst during the polymerization reaction.
  • an organo-aluminium compound being optionally halogenated, having general formula AIR 11 R 12 R 13 or AIR 11 R 12 Y, wherein R 11 , R 12 , R 13 is an alkyl having from 1 to 6 carbon atoms and R 11 , R 12 , R 13 may be the same or different and wherein Y is hydrogen or a halogen, as disclosed in US6930071 and US6864207, which are incorporated herein by reference.
  • Preferred activating agents are Tri-Ethyl Aluminum (TEAI), Tri-lso-Butyl Aluminum (TIBAI), Tri-Methyl Aluminum (TMA), and Methyl-Methyl- Ethyl Aluminum (MMEAI).
  • the activating agent is added to the loop reactor in an activating agent slurry at a concentration of less than 90% by weight of the activating agent slurry composition, more preferably from 10 to 50% by weight, for instance around 20% by weight.
  • concentration of the activating agent in the loop reactor is lower than 200ppm, more preferably from 10 to 100 parts per million, most preferably from 20-70ppm and for instance around 50ppm.
  • the term "monomer” refers to olefin compound that is to be polymerized.
  • olefin monomers are ethylene and propylene.
  • the invention is directed to ethylene.
  • the term "diluent” refers to diluents in a liquid state, liquid at room temperature and preferably liquid under the pressure conditions in the loop reactor.
  • Diluents which are suitable for being used in accordance with the present invention may comprise but are not limited to hydrocarbon diluents such as aliphatic, cycloaliphatic and aromatic hydrocarbon solvents, or halogenated versions of such solvents.
  • the preferred solvents are C12 or lower, straight chain or branched chain, saturated hydrocarbons, C5 to C9 saturated alicyclic or aromatic hydrocarbons or C2 to C6 halogenated hydrocarbons.
  • Non-limiting illustrative examples of solvents are butane, isobutane, pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, methyl cyclopentane, methyl cyclohexane, isooctane, benzene, toluene, xylene, chloroform, chlorobenzenes, tetrachloroethylene, dichloroethane and trichloroethane.
  • said diluent is isobutane.
  • other diluents may as well be applied according to the present invention.
  • Suitable ethylene polymerization includes but is not limited to homopolymerization of ethylene, copolymerization of ethylene and a higher 1 -olefin co-monomer.
  • co-monomer refers to olefin co-monomers which are suitable for being polymerized with ethylene monomers.
  • Co-monomers may comprise but are not limited to aliphatic C3-C20 alpha-olefins.
  • Suitable aliphatic C3-C20 alpha- olefins include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene.
  • co-polymer refers to a polymer, which is made by linking two different types of in the same polymer chain.
  • homo-polymer refers to a polymer which is made by linking ethylene monomers, in the absence of co-monomers. In an embodiment of the present invention, said co-monomer is 1-hexene.
  • reactants comprising the monomer ethylene, isobutane as hydrocarbon diluent, a catalyst, the co-monomer 1-hexene are used.
  • the polymerization can be performed over a wide temperature range.
  • the temperature is within the range of about 0°C to about 1 10°C.
  • a more preferred range is from about 60°C to about 100°C, more preferably from about 80 to 1 10°C,
  • the reactor pressure is preferably held between 20 and 100 bar, 30 to 50 bar, more preferably at pressure of 37 to 45 bar.
  • the slurry flow can be set between 5 and 15 m/s.
  • the pelleted polyethylene product of the invention can be easily produced under flexible processing conditions by using the pelleted first polyethylene resin, while leading to homogeneous pelleted polyethylene product.
  • the method provides advantages such as easy mixing; and easy of processing.
  • the present invention also provides improved master batches, by improving the average MFI and/or the average density.
  • the invention allows preparing polyethylene products with tailor made properties.
  • a first polyethylene resin is produced in a single loop in the presence of a metallocene catalyst. Ethylene was injected with 1-hexene together with the catalyst.
  • the metallocene catalyst used was an activated supported ethylene bis (tetrahydro-indenyl) zirconium dichloride. Isobutane was used as diluent.
  • the polymerization conditions are indicated in Table 1.
  • the produced first polyethylene resin has a density of 0.960 g/cm 3 and a Ml 2 of 8g/10 min with the Melt Index Ml 2 being measured by the procedure of ASTM D-1238 using a temperature of 190°C and a load of 2.16 kg. Table 1
  • TIBAL triisobutylaluminium
  • the first polyethylene resin is extruded with 40% by weight of carbon black pigment, and 4.5% by weight of anti-oxidant, 2.7% by weight of anti-acid, into a pelleted first polyethylene resin.
  • a second polyethylene fluff is produced in a double loop reactor in the presence of a Ziegler-Natta.
  • a Ziegler-Natta catalyst slurry (0.7% by weight; D 50 of 5 ⁇ ) was fed under 200-240 kg/h isobutane flushing into a double loop reactor.
  • TEAI activating agent concentration of 20% by weight; at 50 ppm in the reactor
  • Ethylene monomer was fed at 5-10°C.
  • the reactor temperature was kept at 90°C.
  • the Ziegler-Natta catalyst of D 50 of 5 ⁇ was prepared as described herein:
  • BEM/TEAI (1 :0.03) + 2-ethylhexanol (2-EHOH) ⁇ Mg(2-EHO) 2 ; wherein BEM MgRR' with RH and R'H are butane and ethane, respectively;
  • Step 6 Product D + TEAI ⁇ catalyst 5 ⁇
  • the second polyethylene fluff produced has a density of 0.958 g/cm 3 and HLMI of 8 g/10 min.
  • pelleted first polyethylene resin 5% by weight is physically blended with the second polyethylene fluff to produce a pelleted polyethylene product.
  • the pelleted final product displayed good mechanical properties in particular for pipe application.

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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)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)

Abstract

Cette invention concerne un procédé de préparation d'un produit de polyéthylène pastillé par : (i) production d'une première résine de polyéthylène en présence d'un catalyseur métallocène, ladite première résine polyéthylène ayant une densité, mesurée par le test normalisé ASTM D-1505 à une température de 23°C, de 0,940 à 0,970 g/cm3 ; (ii) extrusion de la première résine polyéthylène avec au moins un additif choisi parmi les pigments, les stabilisants UV, les antioxydants, les charges, les agents antistatiques, les agents d'aide à la dispersion, les auxiliaires de traitement, les agents antiacides, et leurs mélanges, pour obtenir une première résine polyéthylène pastillée; (iii) production séparée d'une seconde résine polyéthylène en présence d'un catalyseur de Ziegler-Natta et/ou de chrome; et (iv) mélange physique de 1 à 35 % en poids de la première résine polyéthylène pastillée avec le polyéthylène de l'étape (iii) pour obtenir le produit de polyéthylène pastillé selon l'invention, les % en poids étant basés sur le poids total du produit de polyéthylène pastillé.
PCT/EP2012/053661 2011-03-04 2012-03-02 Procédé de préparation de produits de polyéthylène pastillés WO2012119956A1 (fr)

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US9512283B2 (en) 2014-10-21 2016-12-06 NOVA Chemicals (International S.A. Rotomolded articles
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US10023730B2 (en) 2014-10-21 2018-07-17 Nova Chemicals (International) S.A. HDPE articles
US9512282B2 (en) 2014-10-21 2016-12-06 Nova Chemicals (International) S.A. Dilution index
US10023729B2 (en) 2014-10-21 2018-07-17 Nova Chemicals (International) S.A. Films produced from ethylene interpolymer products
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US9518159B2 (en) 2014-10-21 2016-12-13 Nova Chemicals (International) S.A. Ethylene interpolymer films
US9695309B2 (en) 2014-10-21 2017-07-04 Nova Chemicals (International) S.A. Rotomolded articles
US10000630B2 (en) 2014-10-21 2018-06-19 Nova Chemicals (International) S.A. Ethylene interpolymers having improved color
US10023706B2 (en) 2014-10-21 2018-07-17 Nova Chemicals (International) S.A. Rotomolded articles
US11078351B2 (en) 2014-10-21 2021-08-03 Nova Chemicals (International) S.A. Ethylene interpolymers having improved color
US9505893B2 (en) 2014-10-21 2016-11-29 Nova Chemicals (International) S.A. Caps and closures
US9512283B2 (en) 2014-10-21 2016-12-06 NOVA Chemicals (International S.A. Rotomolded articles
US10040928B2 (en) 2014-10-21 2018-08-07 Nova Chemicals (International) S.A. Rotomolded articles
US10053565B2 (en) 2014-10-21 2018-08-21 Nova Chemicals (International) S.A. Ethylene interpolymer films
US10053564B2 (en) 2014-10-21 2018-08-21 Nova Chemicals (International) S.A. Caps and closures
US9505892B2 (en) 2014-10-21 2016-11-29 Nova Chemicals (International) S.A. HDPE articles
US10577491B2 (en) 2014-10-21 2020-03-03 Nova Chemicals (International) S.A. Dilution index
US10954365B2 (en) 2014-10-21 2021-03-23 Nova Chemicals (International) S.A. Dilution index
US10329412B2 (en) 2017-02-16 2019-06-25 Nova Chemicals (International) S.A. Caps and closures

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