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
  • 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
  • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
• • 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 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 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), optionally 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
• 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 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 in that 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 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 first ethylene polymer component (A) may be produced in a slurry loop reactor and the second ethylene polymer component (B) may be produced in a slurry loop reactors, preferably where both 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.
• 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 and/or optical appearance 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 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 26 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, further preferred > 26 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. This may further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/
• 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/or (B) and/or between > 50 and 70, preferably 51 and 65, preferably 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 further contribute to improve and/or optimize material properties, especially optical properties such as transparency, and/or mechanical properties. This also 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 50 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, below 1200, below 1000 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 preferably below 14000. This may contribute to further improve the optical appearance
• 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 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.
• 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 a prepolymer (P) may be produced in the amount of for example 0.1 to ⁇ 7 wt%, preferably 0.1 to ⁇ 5% 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.
• the prepolymerization may thereby be carried out in 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 % .
• 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%.
• Three samples IE1, IE2 and CE of were produced using prepolymerization followed by polymerization in a first slurry reactor (loop reactor 1) by feeding ethylene (C2), 1- butene (C4) as comonomer, one metallocene catalyst as described below, 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 IE1 and IE 2 compared to CE, especially for gels with a size > 1000 microns and/or with a size of 600-1000 micron and/or with a size of 300-599 micron.
• Optical appearance is further improved for IE1 as also the number of very small gels with a size of 100-299 micron decreases compared to IE2 and CE . Table 1.

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• 2020
  • 2020-07-15 CN CN202080061708.1A patent/CN114402003B/zh active Active
  • 2020-07-15 EP EP20737483.6A patent/EP3999565A1/de active Pending
  • 2020-07-15 WO PCT/EP2020/069926 patent/WO2021009189A1/en unknown

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