EP3999566A1 - Process for producing a polymer composition - Google Patents

Process for producing a polymer composition

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Publication number
EP3999566A1
EP3999566A1 EP20737484.4A EP20737484A EP3999566A1 EP 3999566 A1 EP3999566 A1 EP 3999566A1 EP 20737484 A EP20737484 A EP 20737484A EP 3999566 A1 EP3999566 A1 EP 3999566A1
Authority
EP
European Patent Office
Prior art keywords
ethylene
polymer
polymer component
ethylene polymer
producing
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.)
Pending
Application number
EP20737484.4A
Other languages
German (de)
French (fr)
Inventor
Girish Suresh GALGALI
Friedrich Berger
Jani Aho
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.)
Borealis AG
Original Assignee
Borealis AG
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 Borealis AG filed Critical Borealis AG
Publication of EP3999566A1 publication Critical patent/EP3999566A1/en
Pending legal-status Critical Current

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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
    • C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00—Polymerisation catalysts
    • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62—Refractory metals or compounds thereof
    • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
    • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
    • C08F4/65912—Component covered by group C08F4/64 containing a transition metal-carbon bond in combination with an organoaluminium compound
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00—Polymerisation catalysts
    • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62—Refractory metals or compounds thereof
    • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
    • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
    • C08F4/65916—Component covered by group C08F4/64 containing a transition metal-carbon bond supported on a carrier, e.g. silica, MgCl2, polymer
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00—Polymerisation catalysts
    • C08F4/42—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors
    • C08F4/44—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides
    • C08F4/60—Metals; Metal hydrides; Metallo-organic compounds; Use thereof as catalyst precursors selected from light metals, zinc, cadmium, mercury, copper, silver, gold, boron, gallium, indium, thallium, rare earths or actinides together with refractory metals, iron group metals, platinum group metals, manganese, rhenium technetium or compounds thereof
    • C08F4/62—Refractory metals or compounds thereof
    • C08F4/64—Titanium, zirconium, hafnium or compounds thereof
    • C08F4/659—Component covered by group C08F4/64 containing a transition metal-carbon bond
    • C08F4/6592—Component covered by group C08F4/64 containing a transition metal-carbon bond containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring
    • C08F4/65922—Component covered by group C08F4/64 containing a transition metal-carbon bond containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring containing at least two cyclopentadienyl rings, fused or not
    • C08F4/65925—Component covered by group C08F4/64 containing a transition metal-carbon bond containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring containing at least two cyclopentadienyl rings, fused or not two cyclopentadienyl rings being mutually non-bridged
    • 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
    • C08J2323/08—Copolymers of ethene
    • 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
    • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
    • 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
    • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend

Definitions

  • the present invention relates to a process for producing a polymer composition, especially for pipes, caps, closures, rotomolded articles, artificial grass mats, geomembranes, blow molded articles and/or mono or multilayer films.
  • metallocene catalysts to improve optical properties, like for example transparency and/or mechanical properties are also known in the art.
  • the present invention provides a process for producing a polymer composition wherein: that a prepolymer based on ethylene (P) is obtained in a prepolymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a first ethylene polymer component (A) is obtained in a first polymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha- olefins having from 4 to 10 carbon atoms and optionally hydrogen and a second ethylene polymer component (B) is obtained in a second polymerization zone by polymerization conducted in slurry in the presence of ethylene, first ethylene
  • the densities of ethylene polymer components (A) and (B) are each between 925 and 970 kg/m 3 and the density of ethylene polymer component (C) has a density between 880 and 950 kg/m 3 , wherein further the ethylene polymer components (A), (B) and (C) have different MFR2 values.
  • the process according to the present invention thereby allows to combine good optical properties, especially a high transparency, and/or good mechanical properties and/or a good processability with a good optical appearance, especially a low level of defects, particularly low levels of gels, particularly low levels of gels with a size > 1000 microns and/or with a size of 600-1000 micron and/or with a size of 300-599 micron and/or with a size of 100-299 micron.
  • Gels or defects may thereby especially for example be due to cross-linked and/or high molecular weight polymer components.
  • High-transparency in the sense of the invention may be obtained especially for example for metallocene LLDPEs and/or may mean for example a light transmission in the visible spectrum of > 75 %, preferably > 80 %.
  • Different MFR2 values in the sense of the present invention may thereby be for example values that differ by 0.5, 0.1, 0.01 or even 0.001. That the ethylene polymer components (A), (B) and (C) have different MFR2 values may thereby mean that the multimodal ethylene polymer (a) may be for example bimodal or trimodal from a molecular weight point of view.
  • the molecular weight distribution (MWD) is thereby equivalent to Mw/Mn as measured by GPC in a suitable way.
  • the weight percent (wt%) of ethylene polymer components (A), (B) and (C) are given based on the weight of the polymer, namely the multimodal ethylene polymer (a), of the composition and thereby add up to > 93 wt%, preferably > 95 wt% or 100 wt% of the polymer, namely the multimodal ethylene polymer (a), in the polymer composition according to the invention.
  • values in weight percent (wt%) for ethylene polymer components (A), (B) and (C) may have to be selected, preferably in their respective ranges, so that they add up to > 93 wt%, preferably > 95 wt% or 100 wt% of the polymer, namely the multimodal ethylene polymer (a), in the polymer composition according to the invention.
  • the second ethylene polymer component (B) may preferably be obtained in the presence of the first ethylene polymer component (A) and/or the third ethylene polymer component (C) may be obtained in the presence of the first ethylene polymer component (A) and/or the second ethylene polymer component (B). Nonetheless (and in contrast to the second ethylene polymer component (B)), third ethylene polymer component (C) as used herein may preferably refer (only) to the component produced in the third polymerization zone, as such.
  • the prepolymer based on ethylene (P) and/or the first and/or second ethylene polymer components (A) and/or (B) may be obtained in the presence of 1 -butene, 1 -hexene and/or 1-octene as comonomer and/or the third ethylene polymer component (C) may be obtained in the presence of 1 -butene, 1 hexene and/or 1-octene as comonomer.
  • This may contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
  • the prepolymerization zone and/or the first and/or second polymerization zone may comprise at least one slurry loop reactor and the third polymerization zone comprises at least one gas phase reactor, preferably connected in series. This may contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
  • the prepolymer based on ethylene (P) and/or the first ethylene polymer component (A) may be produced in a slurry loop reactor and the second ethylene polymer component (B) is produced in a slurry loop reactors, preferably where the two or three slurry loop reactors are connected in series. This may contribute to improve the homogeneity of the composition.
  • the first and second polymerization zones each may comprise one slurry loop reactor connected in series, whereby hydrogen is fed only to the first of these slurry loop reactors and both of these slurry loops reactors are otherwise run under the same/similar conditions or different conditions, preferably under the same/similar conditions, whereby preferably both of these slurry loops reactors are run at a temperature of between 70 and 95 °C and/or a pressure of 5000-6000 kPa and/or preferably both of these slurry loops reactors are run at the same temperature ⁇ 10 % or ⁇ 5 °C and/or at the same pressure ⁇ 10 % or ⁇ 50 kPa.
  • the prepolymerization zone may be the smallest of the reactors used, whereby preferably prepolymerization may be carried out at temperature lower than the temperature in the first and/or second polymerization zone, preferably at a temperature lower than both slurry loop reactors, preferably in the range of 30 to 70 °C and/or prepolymerization may be carried out at a pressure of 5000-6000 kPa and/or the concentration of hydrogen (in mol/kmol) in the prepolymerization zone may be the same as the concentration of hydrogen (in mol/kmol) in the first polymerization zone ⁇ 30 %, preferably ⁇ 20 %, preferably ⁇ 10 %. Similar conditions in the sense of the present inventions may thereby be conditions that deviate for example only by ⁇ 25 %,
  • ⁇ 20 % or ⁇ 10 % are identical conditions. Different conditions in the sense of the invention may mean different by > ⁇ 20 %, preferably > ⁇ 25 %. This may further contribute to improve the homogeneity of the composition.
  • the polymerization of a third ethylene polymer component (C) in a third polymerization zone may preferably conducted in gas phase in the presence of at least one comonomer that is different from the comonomer present in the first and/or second polymerization zone, preferably so that the molecular weight is maximized and/or in the with no hydrogen fed to the second polymerization zone.
  • This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
  • the ethylene polymer component (A) may have a MFR 2 lower than the MFR 2 of ethylene polymer component (B), preferably of 5 to 50, preferably of 5 to 45, preferably of 7 to 40, more preferably of 10 to 30 g/ 10 min, further preferred 15 to 27 g/lOmin and/or the ethylene polymer component (B) may have an MFR 2 5 to 50 g/10 min, preferably of 5 to 45, preferably of 7 to 40, more preferably of 10 to 35 g/10 min, further preferred 15 to 34 g/lOmin and/or the MFR 5 of the ethylene polymer component (C) may be 0.01 to 5, preferably 0.05 to 3, preferably 0.5 to ⁇ 2 g/lOmin all measured according to ISO 1133 at 190°C under 2.16 kg or 5 kg load and/or wherein the MFR.2of the prepolymer may be in the range of 5 to 50, preferably may be the same as the MFR2
  • the alpha- olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer components (A) and (B) may be 1 -butene and the alpha-olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer component (C) may be 1 -hexene and/or the multimodal polymer of ethylene (a) may comprise between 15 and 24, preferably 17 and ⁇ 24 wt% of the ethylene polymer components (A) and (B) and/or between > 51 and 65, preferably 55 and ⁇ 65 wt%, 52 and 63 wt%, preferably > 52 and ⁇ 63 wt% or > 50 and ⁇ 60 wt% of the ethylene polymer component (C). This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
  • the ethylene polymer component (B) may have a density equal or lower than the density of the ethylene polymer component (A). This may contribute to improve the homogeneity of the composition and/or to further improve the optical appearance.
  • the density of the ethylene component (C) is equal or lower than the density of the ethylene polymer component (A) and/or of ethylene polymer component (B). This may contribute to improve the homogeneity of the composition and/or to further improve the optical appearance.
  • the density of the ethylene polymer components (A) and (B) may be of 930 to 945, preferably 931 to 945, preferably > 931 to ⁇ 945, preferably of 935 to 945 kg/m 3 and/or the density of polymer component (C) may be of 905 to 955, preferably 910 to 940, preferably 915 to 950, further preferred 925 to 945 or 930 to 942 kg/m 3 or of 945 to 965, preferably of 950 to ⁇ 965 kg/m 3 and/or the density of polymer component (C) may be of 920 to 945, preferably 925 to ⁇ 945, preferably 930 to ⁇ 945 kg/m 3 . This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. In addition, this may also contribute to improve the homogeneity of the composition.
  • the density of the multimodal polymer of ethylene (a) may be of 915 to 955, preferably of 930 to 950, kg/m 3 and/or the MFR2 of the multimodal polymer of ethylene (a) may be between 0.1 and 10, preferably 0.5 and 8, preferably 0.6 and 3 g/lOmin and/or the multimodal polymer of ethylene (a) may have an MFR21/ MFR2 of 10 to 40, preferably 15 to 35, preferably 20 to ⁇ 35, preferably > 25 to ⁇ 35 and/or the multimodal polymer of ethylene (a) may have an MFR5 of 1 to 5, preferably > 1 to ⁇ 3 g/lOmin. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties
  • the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size of 600-1000 micron of > 0 to below 150, preferably below 100, preferably below 75, preferably below 60 and/or the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size of 300-599 micron of > 0 to below 1500, preferably below 1450, below 1400 and/or the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size > 1000 micron of 0 to below 2, preferably below 1 and/or the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size of 100-299 micron of > 0 to below 70000, preferably below 40000, preferably 20000. This may contribute to further improve the optical appearance
  • the multimodal polymer of ethylene (a) may be produced using a single site catalyst, preferably a substituted and/or bridged bis-cyclopentadienyl zirconium or hafnium catalyst and/or preferably the ethylene polymer components (A), (B) and (C) of the polymer of ethylene (a) may be produced using same single site catalyst, preferably a substituted and/or bridged bis-cyclopentadienyl zirconium or hafnium catalyst and/or may have each an MWD of between 2.0 and 5.0, preferably 2.5 and 4.5, preferably >
  • This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. In addition, this may also contribute to improve the homogeneity of the composition and/or the optical appearance.
  • the present invention also concerns a pipe, cap, closure, rotomolded article, artificial grass mat, geomembrane, blow molded article and/or mono or multilayer film
  • Such articles may show good optical properties, especially a high transparency, and/or good mechanical properties and/or a good processability in combination with a good optical appearance, especially a low level of defects, particularly low levels of gels, particularly low levels of gels with a size > 1000 microns and/or with a size of 600- 1000 micron and/or with a size of 300-599 micron and/or with a size of 100-299 micron. This may contribute to improve optical appearance.
  • the main polymerization stages are preferably carried out as a combination of slurry polymerization/gas-phase polymerization.
  • the slurry polymerization is preferably performed in a so-called slurry loop reactor.
  • the main polymerization stages may be preceded by a pre polymerization, in which case an ethylene based prepolymer (P) may be produced in the amount of for example 0.1 to ⁇ 7 wt%, preferably 0.1 to ⁇ 5 wt% preferably 1 to 4 wt% by weight of the total amount of polymers is produced.
  • the pre-polymer may be an ethylene homo- or copolymer, preferably an ethylene copolymer, further preferred with 1 -butene.
  • the weight percent (wt%) of ethylene polymer components (A), (B) and (C) are given based on the weight of the polymer, namely the multimodal ethylene polymer (a), of the polymer composition and thereby add up to > 93 wt%, preferably > 95 wt%, of polymer, namely the multimodal ethylene polymer (a), in the polymer composition according to the invention, so that the weight percent (wt%) of ethylene polymer components (A), (B), (C) and prepolymer (P) have to be selected in their respective ranges to add up to 100 wt% based on the weight of polymer, namely the multimodal ethylene polymer (a), in the polymer composition.
  • This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. In addition, this may also contribute to improve the homogeneity of the composition and/or the optical appearance.
  • a pre-polymerization takes place, in this case all of the catalyst is preferably charged into the first prepolymerization reactor and the pre-polymerization is performed as slurry polymerization.
  • Such a polymerization leads to less fine particles being produced in the following reactors and to a more homogeneous product being obtained in the end.
  • the resulting multimodal polymer of ethylene (a) consists of an intimate mixture of the polymers from the three main reactors, the different molecular-weight- distribution curves of these polymers together forming a molecular-weight- distribution curve having a broad maximum or three maxima, i.e. the end product is a trimodal polymer mixture.
  • the polymer composition according to the invention may also comprise additives like process aids, antioxidants, pigments, UV-stabilizers and the like.
  • the amount at those additives may be 0 to 10 wt% or > 0 to 10 wt%, based on the weight of the total composition. This means that the amount of polymer, namely the multimodal ethylene polymer (a), in the polymer composition may 90 wt% to 100 wt% or 90 wt% to ⁇ 100 wt%.
  • CE1, CE2 and IE of were produced using prepolymerization followed by polymerization in a first slurry reactor (loop reactor 1) by feeding ethylene (C2), one metallocene catalyst as described below, 1 -butene (C4) as comonomer, hydrogen and propane as a diluent.
  • first slurry loop reactor is connected in series with another slurry reactor (loop reactor 2), so that the first ethylene polymer component (A) produced in the loop reactor 1 is fed to the loop reactor 2.
  • Ethylene (C2) is thereby polymerized in the presence of the polymer produced in the loop reactor 1, 1 -butene (C4) as comonomer and hydrogen to produce a second ethylene component (B).
  • the loop reactor 2 is thereby connected in series to a gas phase reactor (GPR), so that the second ethylene component (B) is fed to the GPR and ethylene is polymerized in the GPR with 1 -hexene (C6) as comonomer as well as hydrogen to obtain a third ethylene polymer component (C), so as to produces multimodal polymers of ethylene (a).
  • GPR gas phase reactor
  • the process comprises of a flash between loop2 reactor and GPR reactor, in order to remove the diluent and unreacted monomer(s).
  • the MWD of each sample was determined to be in the range from 2-6 by GPC.
  • the MWD of each ethylene polymer component was determined to be in the range of 2 to 4 by GPC.
  • a Waters 150CV plus instrument, equipped with refractive index detector and online viscosimeter was used with 3 x HT6E styragel columns from Waters (styrene- divinylbenzene) and 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg/L 2,6-Di tert butyl-4-methyl-phenol) as solvent at 140 °C and at a constant flow rate of 1 mL/min.
  • a translucent 70 pm thick cast film was photographed using high resolution line cameras and appropriate background illumination. The number and the area of gels per total film area are then calculated using an image recognition software. The film defects/gels are measured and classified according to their size (longest dimension).
  • Screw type 3 Zone, nitrated
  • optical appearance is improved as the number of gels decreases for IE compared to CE1 and CE2.

Abstract

The present invention concerns aprocess for producing a polymer composition characterized in that a prepolymer based on ethylene (P) is obtained in a prepolymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a first ethylene polymer component (A) is obtained in a first polymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a second ethylene polymer component (B) is obtained in asecond polymerization zone by polymerization conducted in slurry in the presence of ethylene, first ethylene polymer component (A), at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a third ethylene polymer component (C ) is obtained in a third polymerization zone by polymerization conducted in gas phase in the presence of ethylene and, at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms, to produce a multimodal polymer of ethylene (a) with at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms, -which has a) a density between 900 and 960 kg/m 3 b) MFR 2 of 0.1 to 25g/10 min (according to ISO 1133 at 190°C under 2.16 kg load), c) MWD of 2 to 6, -which comprises at least -between 0.5 to <5 wt% of an prepolymer based on ethylene (P) -between 10 to < 25 wt% of an ethylene polymer component (A), -between 10 to < 25 wt% of an ethylene polymer component (B) and -between > 51 and 79.5 wt% of an ethylene polymer component (C) and wherein the densities of ethylene polymer components (A) and (B) are each between 925 and 970 kg/m3 and the density of ethylene polymer component (C) has a density between 880 and 950 kg/m3, wherein further the ethylene polymer components (A), (B) and (C) have different MFR2 values.

Description

Process for producing a polymer composition
The present invention relates to a process for producing a polymer composition, especially for pipes, caps, closures, rotomolded articles, artificial grass mats, geomembranes, blow molded articles and/or mono or multilayer films.
Various processes for producing polymer compositions are known in the art. These comprise multi-stage processes that allow to fine tune the properties of the materials and for example to improve mechanical properties and/or processability or the balance thereof.
In addition, the use of metallocene catalysts to improve optical properties, like for example transparency and/or mechanical properties are also known in the art.
However, in particular good optical appearance remains a significant challenge. This challenge becomes even more apparent and pressing with materials already having particularly good optical properties, especially a high transparency because in such cases, even slight defects such as for example gels can have a significant negative impact on optical appearance.
It is thus the object of the present invention to improve the optical appearance of articles produced with a polymer composition, especially a polymer composition having a high transparency and/or obtained with a metallocene catalyst. Therefore, the present invention provides a process for producing a polymer composition wherein: that a prepolymer based on ethylene (P) is obtained in a prepolymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a first ethylene polymer component (A) is obtained in a first polymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha- olefins having from 4 to 10 carbon atoms and optionally hydrogen and a second ethylene polymer component (B) is obtained in a second polymerization zone by polymerization conducted in slurry in the presence of ethylene, first ethylene polymer component (A), at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a third ethylene polymer component (C ) is obtained in a third polymerization zone by polymerization conducted in gas phase in the presence of ethylene and, at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms, to produce a multimodal polymer of ethylene (a) with at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms,
- which has
a) a density between 900 and 960 kg/m3
b) MFR.2 of 0.1 to 25 g/10 min (according to ISO 1133 at 190°C under 2.16 kg load), c) MWD of 2 to 6,
- which comprises at least
- between 0.5 to <7 wt% of an prepolymer based on ethylene (P)
- between 10 to < 25 wt% of an ethylene polymer component (A),
- between 10 to < 25 wt% of an ethylene polymer component (B) and
- between > 51 and 79.5 wt% of an ethylene polymer component (C)
and wherein the densities of ethylene polymer components (A) and (B) are each between 925 and 970 kg/m3 and the density of ethylene polymer component (C) has a density between 880 and 950 kg/m3, wherein further the ethylene polymer components (A), (B) and (C) have different MFR2 values.
The process according to the present invention thereby allows to combine good optical properties, especially a high transparency, and/or good mechanical properties and/or a good processability with a good optical appearance, especially a low level of defects, particularly low levels of gels, particularly low levels of gels with a size > 1000 microns and/or with a size of 600-1000 micron and/or with a size of 300-599 micron and/or with a size of 100-299 micron. Gels or defects may thereby especially for example be due to cross-linked and/or high molecular weight polymer components. High-transparency in the sense of the invention may be obtained especially for example for metallocene LLDPEs and/or may mean for example a light transmission in the visible spectrum of > 75 %, preferably > 80 %.
Different MFR2 values in the sense of the present invention may thereby be for example values that differ by 0.5, 0.1, 0.01 or even 0.001. That the ethylene polymer components (A), (B) and (C) have different MFR2 values may thereby mean that the multimodal ethylene polymer (a) may be for example bimodal or trimodal from a molecular weight point of view.
The molecular weight distribution (MWD) is thereby equivalent to Mw/Mn as measured by GPC in a suitable way.
The weight percent (wt%) of ethylene polymer components (A), (B) and (C) are given based on the weight of the polymer, namely the multimodal ethylene polymer (a), of the composition and thereby add up to > 93 wt%, preferably > 95 wt% or 100 wt% of the polymer, namely the multimodal ethylene polymer (a), in the polymer composition according to the invention. For avoidance of doubt, this means that values in weight percent (wt%) for ethylene polymer components (A), (B) and (C) may have to be selected, preferably in their respective ranges, so that they add up to > 93 wt%, preferably > 95 wt% or 100 wt% of the polymer, namely the multimodal ethylene polymer (a), in the polymer composition according to the invention.
In a process for producing a polymer composition according to the invention, the second ethylene polymer component (B) may preferably be obtained in the presence of the first ethylene polymer component (A) and/or the third ethylene polymer component (C) may be obtained in the presence of the first ethylene polymer component (A) and/or the second ethylene polymer component (B). Nonetheless (and in contrast to the second ethylene polymer component (B)), third ethylene polymer component (C) as used herein may preferably refer (only) to the component produced in the third polymerization zone, as such.
In a process for producing a polymer composition according to the invention, the prepolymer based on ethylene (P) and/or the first and/or second ethylene polymer components (A) and/or (B) may be obtained in the presence of 1 -butene, 1 -hexene and/or 1-octene as comonomer and/or the third ethylene polymer component (C) may be obtained in the presence of 1 -butene, 1 hexene and/or 1-octene as comonomer. This may contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
In a process for producing a polymer composition according to the invention, the prepolymerization zone and/or the first and/or second polymerization zone may comprise at least one slurry loop reactor and the third polymerization zone comprises at least one gas phase reactor, preferably connected in series. This may contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
In a process for producing a polymer composition according to the invention, the prepolymer based on ethylene (P) and/or the first ethylene polymer component (A) may be produced in a slurry loop reactor and the second ethylene polymer component (B) is produced in a slurry loop reactors, preferably where the two or three slurry loop reactors are connected in series. This may contribute to improve the homogeneity of the composition.
In a process for producing a polymer composition according to the invention, the first and second polymerization zones each may comprise one slurry loop reactor connected in series, whereby hydrogen is fed only to the first of these slurry loop reactors and both of these slurry loops reactors are otherwise run under the same/similar conditions or different conditions, preferably under the same/similar conditions, whereby preferably both of these slurry loops reactors are run at a temperature of between 70 and 95 °C and/or a pressure of 5000-6000 kPa and/or preferably both of these slurry loops reactors are run at the same temperature ± 10 % or ± 5 °C and/or at the same pressure ± 10 % or ± 50 kPa. and/or the prepolymerization zone may be the smallest of the reactors used, whereby preferably prepolymerization may be carried out at temperature lower than the temperature in the first and/or second polymerization zone, preferably at a temperature lower than both slurry loop reactors, preferably in the range of 30 to 70 °C and/or prepolymerization may be carried out at a pressure of 5000-6000 kPa and/or the concentration of hydrogen (in mol/kmol) in the prepolymerization zone may be the same as the concentration of hydrogen (in mol/kmol) in the first polymerization zone ± 30 %, preferably ± 20 %, preferably ± 10 %. Similar conditions in the sense of the present inventions may thereby be conditions that deviate for example only by ± 25 %,
± 20 % or ± 10 % . The same conditions in the sense of the present invention are identical conditions. Different conditions in the sense of the invention may mean different by > ±20 %, preferably > ±25 %. This may further contribute to improve the homogeneity of the composition.
In a process for producing a polymer composition according to the invention, the polymerization of a third ethylene polymer component (C) in a third polymerization zone may preferably conducted in gas phase in the presence of at least one comonomer that is different from the comonomer present in the first and/or second polymerization zone, preferably so that the molecular weight is maximized and/or in the with no hydrogen fed to the second polymerization zone. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
In a process for producing a polymer composition according to the invention, the ethylene polymer component (A) may have a MFR2 lower than the MFR2 of ethylene polymer component (B), preferably of 5 to 50, preferably of 5 to 45, preferably of 7 to 40, more preferably of 10 to 30 g/ 10 min, further preferred 15 to 27 g/lOmin and/or the ethylene polymer component (B) may have an MFR2 5 to 50 g/10 min, preferably of 5 to 45, preferably of 7 to 40, more preferably of 10 to 35 g/10 min, further preferred 15 to 34 g/lOmin and/or the MFR5 of the ethylene polymer component (C) may be 0.01 to 5, preferably 0.05 to 3, preferably 0.5 to < 2 g/lOmin all measured according to ISO 1133 at 190°C under 2.16 kg or 5 kg load and/or wherein the MFR.2of the prepolymer may be in the range of 5 to 50, preferably may be the same as the MFR2 of the first ethylene polymer component ±40%, preferably ± 30 %, preferably ± 20 %, preferably ± 10 %. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. In addition, this may also contribute to improve the homogeneity of the composition.
In a process for producing a polymer composition according to the invention, the alpha- olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer components (A) and (B) may be 1 -butene and the alpha-olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer component (C) may be 1 -hexene and/or the multimodal polymer of ethylene (a) may comprise between 15 and 24, preferably 17 and < 24 wt% of the ethylene polymer components (A) and (B) and/or between > 51 and 65, preferably 55 and < 65 wt%, 52 and 63 wt%, preferably > 52 and < 63 wt% or > 50 and < 60 wt% of the ethylene polymer component (C). This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties.
In a process for producing a polymer composition according to the invention, the ethylene polymer component (B) may have a density equal or lower than the density of the ethylene polymer component (A). This may contribute to improve the homogeneity of the composition and/or to further improve the optical appearance.
In a process for producing a polymer composition according to the invention, the density of the ethylene component (C) is equal or lower than the density of the ethylene polymer component (A) and/or of ethylene polymer component (B). This may contribute to improve the homogeneity of the composition and/or to further improve the optical appearance.
In a process for producing a polymer composition according to the invention, the density of the ethylene polymer components (A) and (B) may be of 930 to 945, preferably 931 to 945, preferably > 931 to <945, preferably of 935 to 945 kg/m3 and/or the density of polymer component (C) may be of 905 to 955, preferably 910 to 940, preferably 915 to 950, further preferred 925 to 945 or 930 to 942 kg/m3 or of 945 to 965, preferably of 950 to < 965 kg/m3 and/or the density of polymer component (C) may be of 920 to 945, preferably 925 to < 945, preferably 930 to <945 kg/m3. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. In addition, this may also contribute to improve the homogeneity of the composition.
In a process for producing a polymer composition according to the invention, the density of the multimodal polymer of ethylene (a) may be of 915 to 955, preferably of 930 to 950, kg/m3 and/or the MFR2 of the multimodal polymer of ethylene (a) may be between 0.1 and 10, preferably 0.5 and 8, preferably 0.6 and 3 g/lOmin and/or the multimodal polymer of ethylene (a) may have an MFR21/ MFR2 of 10 to 40, preferably 15 to 35, preferably 20 to < 35, preferably > 25 to < 35 and/or the multimodal polymer of ethylene (a) may have an MFR5 of 1 to 5, preferably > 1 to < 3 g/lOmin. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties
In a process for producing a polymer composition according to the invention, the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size of 600-1000 micron of > 0 to below 150, preferably below 100, preferably below 75, preferably below 60 and/or the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size of 300-599 micron of > 0 to below 1500, preferably below 1450, below 1400 and/or the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size > 1000 micron of 0 to below 2, preferably below 1 and/or the multimodal polymer of ethylene (a) may have a number of gels per square meter with a size of 100-299 micron of > 0 to below 70000, preferably below 40000, preferably 20000. This may contribute to further improve the optical appearance
In a process for producing a polymer composition according to the invention, the multimodal polymer of ethylene (a) may be produced using a single site catalyst, preferably a substituted and/or bridged bis-cyclopentadienyl zirconium or hafnium catalyst and/or preferably the ethylene polymer components (A), (B) and (C) of the polymer of ethylene (a) may be produced using same single site catalyst, preferably a substituted and/or bridged bis-cyclopentadienyl zirconium or hafnium catalyst and/or may have each an MWD of between 2.0 and 5.0, preferably 2.5 and 4.5, preferably >
2.5 and < 4. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. In addition, this may also contribute to improve the homogeneity of the composition and/or the optical appearance.
The present invention also concerns a pipe, cap, closure, rotomolded article, artificial grass mat, geomembrane, blow molded article and/or mono or multilayer film
comprising a polymer composition produced using a process according to the invention. Such articles may show good optical properties, especially a high transparency, and/or good mechanical properties and/or a good processability in combination with a good optical appearance, especially a low level of defects, particularly low levels of gels, particularly low levels of gels with a size > 1000 microns and/or with a size of 600- 1000 micron and/or with a size of 300-599 micron and/or with a size of 100-299 micron. This may contribute to improve optical appearance.
To produce polymer compositions, such as in the present invention, two or more reactors or zones connected in series as described in EP 517 868, which is hereby incorporated by way of reference in its entirety, can be used.
According to the present invention, the main polymerization stages are preferably carried out as a combination of slurry polymerization/gas-phase polymerization. The slurry polymerization is preferably performed in a so-called slurry loop reactor.
Optionally, the main polymerization stages may be preceded by a pre polymerization, in which case an ethylene based prepolymer (P) may be produced in the amount of for example 0.1 to < 7 wt%, preferably 0.1 to < 5 wt% preferably 1 to 4 wt% by weight of the total amount of polymers is produced. The pre-polymer may be an ethylene homo- or copolymer, preferably an ethylene copolymer, further preferred with 1 -butene.
In the case there is a pre-polymerization the weight percent (wt%) of ethylene polymer components (A), (B) and (C) are given based on the weight of the polymer, namely the multimodal ethylene polymer (a), of the polymer composition and thereby add up to > 93 wt%, preferably > 95 wt%, of polymer, namely the multimodal ethylene polymer (a), in the polymer composition according to the invention, so that the weight percent (wt%) of ethylene polymer components (A), (B), (C) and prepolymer (P) have to be selected in their respective ranges to add up to 100 wt% based on the weight of polymer, namely the multimodal ethylene polymer (a), in the polymer composition. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. In addition, this may also contribute to improve the homogeneity of the composition and/or the optical appearance.
If a pre-polymerization takes place, in this case all of the catalyst is preferably charged into the first prepolymerization reactor and the pre-polymerization is performed as slurry polymerization. Such a polymerization leads to less fine particles being produced in the following reactors and to a more homogeneous product being obtained in the end.
The resulting multimodal polymer of ethylene (a) consists of an intimate mixture of the polymers from the three main reactors, the different molecular-weight- distribution curves of these polymers together forming a molecular-weight- distribution curve having a broad maximum or three maxima, i.e. the end product is a trimodal polymer mixture.
The polymer composition according to the invention may also comprise additives like process aids, antioxidants, pigments, UV-stabilizers and the like. Usually, the amount at those additives may be 0 to 10 wt% or > 0 to 10 wt%, based on the weight of the total composition. This means that the amount of polymer, namely the multimodal ethylene polymer (a), in the polymer composition may 90 wt% to 100 wt% or 90 wt% to < 100 wt%.
Examples
Three samples CE1, CE2 and IE of were produced using prepolymerization followed by polymerization in a first slurry reactor (loop reactor 1) by feeding ethylene (C2), one metallocene catalyst as described below, 1 -butene (C4) as comonomer, hydrogen and propane as a diluent. Whereby the first slurry loop reactor is connected in series with another slurry reactor (loop reactor 2), so that the first ethylene polymer component (A) produced in the loop reactor 1 is fed to the loop reactor 2. Ethylene (C2) is thereby polymerized in the presence of the polymer produced in the loop reactor 1, 1 -butene (C4) as comonomer and hydrogen to produce a second ethylene component (B). The loop reactor 2 is thereby connected in series to a gas phase reactor (GPR), so that the second ethylene component (B) is fed to the GPR and ethylene is polymerized in the GPR with 1 -hexene (C6) as comonomer as well as hydrogen to obtain a third ethylene polymer component (C), so as to produces multimodal polymers of ethylene (a).
The process comprises of a flash between loop2 reactor and GPR reactor, in order to remove the diluent and unreacted monomer(s).
The polymerization conditions are given in Table 1 below.
The MWD of each sample was determined to be in the range from 2-6 by GPC. Similarly, the MWD of each ethylene polymer component was determined to be in the range of 2 to 4 by GPC.
Catalyst preparation:
130 grams of a metallocene complex bis(l-methyl-3-n-butylcyclopentadienyl) zirconium (IV) dichloride (CAS no. 151840-68-5) and 9.67 kg of a 30% solution of commercial methylalumoxane (MAO) in toluene were combined and 3.18 kg dry purified toluene was added. Thus, obtained complex solution was added onto 17kg silica carrier Sylopol 55 SJ (supplied by Grace) by very slow uniform spraying over 2 hours. The temperature was kept below 30°C. The mixture was allowed to react for 3 hours after complex addition at 30°C.
Molecular weights, molecular weight distribution, Mn, Mw, MWD:
The weight average molecular weight Mw and the molecular weight distribution (MWD = Mw/Mn wherein Mn is the number average molecular weight and Mw is the weight average molecular weight) is measured by a method based on ISO 16014-4:2003. A Waters 150CV plus instrument, equipped with refractive index detector and online viscosimeter was used with 3 x HT6E styragel columns from Waters (styrene- divinylbenzene) and 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg/L 2,6-Di tert butyl-4-methyl-phenol) as solvent at 140 °C and at a constant flow rate of 1 mL/min.
500 pL of sample solution were injected per analysis. The column set was calibrated using universal calibration (according to ISO 16014-2:2003) with 10 narrow MWD polystyrene (PS) standards in the range of 1.05 kg/mol to 11 600 kg/mol. Mark
Houwink constants were used for polystyrene and polyethylene (K: 19 xlO 3 dL/g and a: 0.655 for PS, and K: 39 xlO 3 dL/g and a: 0.725 for PE). All samples were prepared by dissolving 0.5 - 3.5 mg of polymer in 4 mL (at 140 °C) of stabilized TCB (same as mobile phase) and keeping for 2 hours at 140 °C and for another 2 hours at 160 °C with occasional shaking prior sampling in into the GPC instrument.
Gel content:
Gel content was analyzed by an Optical Control System (OCS Film-Test FSA100) with a CCD (Charged-Coupled Device) camera provided by Optical Control Systems GmbH, which measures gels and defects in the film produced from the compositions. The gels and defects are recognized optoelectronically by their different light transmittance compared to the film matrix.
A translucent 70 pm thick cast film was photographed using high resolution line cameras and appropriate background illumination. The number and the area of gels per total film area are then calculated using an image recognition software. The film defects/gels are measured and classified according to their size (longest dimension).
Cast film preparation, extrusion parameters:
1. Output 25±4g/min
2. Extruder temperature profile 200/210/210/210/210-Die
3. Film thickness about 70 pm
4. Chill Roll temperature 20°C
5. airknife needed
Technical data for the extruder:
1. Screw type: 3 Zone, nitrated
2. Screw diameter:25mm
3. Screw length: 25D
4. Feeding zone: 10D
5. Compression zone: 4D
6. Die 150mm
The defects were classified according to the size (pm)/m2:
100-299
300-599
600-999
>1000
The results are also shown in Table 1 below.
One can see that optical appearance is improved as the number of gels decreases for IE compared to CE1 and CE2.
Table 1.

Claims

Claims:
1. A process for producing a polymer composition characterized in that a
prepolymer based on ethylene (P) is obtained in a prepolymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a first ethylene polymer component (A) is obtained in a first polymerization zone by polymerization conducted in slurry in the presence of ethylene, optionally at least one comonomer selected from alpha- olefins having from 4 to 10 carbon atoms and optionally hydrogen and a second ethylene polymer component (B) is obtained in a second polymerization zone by polymerization conducted in slurry in the presence of ethylene, first ethylene polymer component (A), at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms and optionally hydrogen and a third ethylene polymer component (C ) is obtained in a third polymerization zone by polymerization conducted in gas phase in the presence of ethylene and, at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms, to produce a multimodal polymer of ethylene (a) with at least one comonomer selected from alpha-olefins having from 4 to 10 carbon atoms,
- which has
a) a density between 900 and 960 kg/m3
b) MFR.2 of 0.1 to 25 g/10 min (according to ISO 1133 at 190°C under 2.16 kg load), c) MWD of 2 to 6,
- which comprises at least
- between 0.5 to <7 wt% of an prepolymer based on ethylene (P)
- between 10 to < 25 wt% of an ethylene polymer component (A),
- between 10 to < 25 wt% of an ethylene polymer component (B) and
- between > 51 and 79.5 wt% of an ethylene polymer component (C)
and wherein the densities of ethylene polymer components (A) and (B) are each between 925 and 970 kg/m3 and the density of ethylene polymer component (C) has a density between 880 and 950 kg/m3, wherein further the ethylene polymer components (A), (B) and (C) have different MFR2 values.
2. A process for producing a polymer composition according to claim 1, characterized in that prepolymer based on ethylene (P) and/or the first and/or second ethylene polymer components (A) and/or (B) is/are obtained in the presence of 1 -butene, 1 -hexene and/or 1-octene as comonomer and/or in that the third ethylene polymer component (C) is obtained in the presence of 1 -butene,
1 hexene and/or 1-octene as comonomer.
3. A process for producing a polymer composition according to claim 1 or 2,
characterized in that the prepolymerization zone and/or the first and/or second polymerization zone comprise at least one slurry loop reactor and the third polymerization zone comprises at least one gas phase reactor, preferably connected in series.
4. A process for producing a polymer composition according to any of the
preceding claims, characterized in that prepolymer based on ethylene (P) and/or the first ethylene polymer component (A) is/are produced in a slurry loop reactor and the second ethylene polymer component (B) is produced in a slurry loop reactors, preferably where the two or three slurry loop reactors are connected in series.
5. A process for producing a polymer composition according to any of the
preceding claims, characterized in that each of the the first and second polymerization zone comprises one slurry loop reactor connected in series, whereby hydrogen is fed only to the first of these slurry loop reactors and both of these slurry loops reactors are otherwise run under the same/similar conditions or different conditions, preferably under the same/similar conditions, preferably both of these slurry loops reactors are run at a temperature of between 70 and 95 °C and/or a pressure of 5000-6000 kPa and/or preferably both of these slurry loops reactors are run at the same temperature ± 10 % or ± 5 °C and/or at the same pressure ± 10 % or ± 50 kPa and/or in that the prepolymerization zone is the smallest of the reactors used, whereby preferably prepolymerization is carried out at temperature lower than the temperature in the first and/or second polymerization zone, preferably at a temperature lower than both slurry loop reactors, preferably in the range of 30 to < 70 °C and/or prepolymerization is carried out at a pressure of 5000-6000 kPa and/or in that the concentration of hydrogen (in mol/kmol) in the prepolymerization zone is the same as the concentration of hydrogen (in mol/kmol) in the first polymerization zone ± 30 %, preferably ± 20 %, preferably ± 10 % .
6. A process for producing a polymer composition according to any of the
preceding claims characterized in that the polymerization of a third ethylene polymer component (C) in a third polymerization zone is preferably conducted in gas phase in the presence of at least one comonomer that is different from the comonomer present in the first and/or second polymerization zone, preferably so that the molecular weight is maximized and/or in the with no hydrogen fed to the second polymerization zone.
7. A process for producing a polymer composition according to any of the
preceding claims , wherein the ethylene polymer component (A) has a MFR2 lower than the MFR2 of ethylene polymer component (B), preferably of 5 to 50, preferably of 5 to 45, preferably of 7 to 40, more preferably of 10 to 30 g/10 min, further preferred 15 to 27 g/lOmin and/or wherein the ethylene polymer component (B) has an MFR2 5 to 50 g/10 min, preferably of 5 to 45, preferably of 7 to 40, more preferably of 10 to 35 g/10 min, further preferred 15 to 34 g/lOmin and/or wherein the MFR5 of the ethylene polymer component (C) is 0.01 to 5, preferably 0.05 to 3, preferably 0.5 to < 2 g/lOmin all measured according to ISO 1133 at 190°C under 2.16 kg or 5 kg load and/or wherein the MFR2 of the prepolymer is in the range of 5 to 50, preferably is the same as the MFR2 of the first ethylene polymer component ±40%, preferably ± 30 %, preferably ± 20 %, preferably ± 10 %.
8. A process for producing a polymer composition according to any of the
preceding claims, wherein the alpha-olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer components (A) and (B) is 1 -butene and the alpha-olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer component (C) is 1 -hexene and/or wherein the multimodal polymer of ethylene (a) comprises betweenl5 and 24, preferably 17 and < 24 wt% of the ethylene polymer components (A) and/or (B) and/or preferably 52 and 63 wt%, preferably > 52 and < 63 or > 50 to < 60 wt% of the ethylene polymer component (C).
9. A process for producing a polymer composition according to any of the
preceding claims, wherein the ethylene polymer component (B) has a density equal or lower than the density of the ethylene polymer component (A).
10. A process for producing a polymer composition according to any of the
preceding claims, wherein the density of the ethylene component (C) is equal or lower than the density of the ethylene polymer component (A) and/or of ethylene polymer component (B)
11. A process for producing a polymer composition according to any of the
preceding claims, wherein the density of the ethylene polymer components (A) and (B) is of 930 to 945, preferably 931 to 945, preferably > 931 to <945, preferably of 935 to 945 kg/m3 and/or the density of polymer component (C) is of 905 to 955, preferably 910 to 940, preferably 915 to 950, further preferred 925 to 945 or 930 to 942 kg/m3 or of 945 to 965, preferably of 950 to < 965 kg/m3 and/or the density of polymer component (C) is of 920 to 945, preferably 925 to < 945, preferably 930 to <945 kg/m3.
12. A process for producing a polymer composition according to any of the
preceding claims, wherein the density of the multimodal polymer of ethylene (a) is of 915 to 955, preferably of 930 to 950, kg/m3 and/or wherein the MFR2 of the multimodal polymer of ethylene (a) is between 0.1 and 10, preferably 0.5 and 8, preferably 0.6 and 3 g/lOmin and/or wherein the multimodal polymer of ethylene (a) has MFR21/ MFR2 of 10 to 40, preferably 15 to 35, preferably 20 to < 35, preferably > 25 to < 35 and/or wherein the multimodal polymer of ethylene (a) has an MFR5 of 1 to 5, preferably > 1 to < 3 g/lOmin
13. A process for producing a polymer composition according to any of the
preceding claims, wherein the multimodal polymer of ethylene (a) has a number of gels per square meter with a size of 600-1000 micron of 0 to below 150, preferably below 100, preferably below 75, preferably below 60 and/or wherein the multimodal polymer of ethylene (a) has a number of gels per square meter with a size of 300-599 micron of 0 to below 1500, preferably below 1450, below 1400 and/or wherein the multimodal polymer of ethylene (a) has a number of gels per square meter with a size > 1000 micron of 0 to below 2, preferably below 1 and/or wherein the multimodal polymer of ethylene (a) has a number of gels per square meter with a size of 100-299 micron of 0 to below 70000, preferably below 40000, preferably 20000.
14. A process for producing a polymer composition according to any of the
preceding claims, wherein the multimodal polymer of ethylene (a) is produced using a single site catalyst, preferably a substituted and/or bridged bis- cyclopentadienyl zirconium or hafnium catalyst and/or preferably wherein the ethylene polymer components (A), (B) and (C) of the polymer of ethylene (a) are produced using same single site catalyst, preferably a substituted and/or bridged bis-cyclopentadienyl zirconium or hafnium catalyst and/or have each an MWD of between 2.0 and 5.0, preferably 2.5 and 4.5, preferably > 2.5 and < 4.
15. A pipe, cap, closure, rotomolded article, artificial grass mat, geomembrane, blow molded article and/or mono or multilayer film comprising the polymer composition produced using a process according to any of the preceding claims 1 to 14.
EP20737484.4A 2019-07-17 2020-07-15 Process for producing a polymer composition Pending EP3999566A1 (en)

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