RU2791110C2 - Bimodal polyethylene - Google Patents

Abstract

FIELD: chemical industry.

SUBSTANCE: invention relates to bimodal polyethylene compositions for the manufacture of products such as pipes, films, sheets, extruded products and products obtained by injection molding. The bimodal polyethylene composition contains a polyethylene component with a lower molecular weight (LMW) and a polyethylene component with a higher molecular weight (HMW), in which each of the polyethylene components, LMW and HMW, contains monomeric units derived from ethylene and sonomeric units derived from (C₃-C₂₀)alpha-olefins. At the same time, the bimodal low-density polyethylene composition is characterized by each of the limitations (a)-(g): (a) bimodality (molecular weight distribution) shown on the chromatogram of gel-penetrating chromatography (GPC) of the bimodal low-density polyethylene composition, where the chromatogram shows a peak representing the polyethylene component HMW, a peak representing the polyethylene component LMW, and the local minimum in the range of Log (molecular weight) (“Log(MW)”)) from 3.0 to 7.0 between the peak representing the polyethylene component HMW and the peak, representing the polyethylene component LMW, measured in accordance with the Bimodality Test Method, (b) density from 0.9310 to 0.9450 g/cm³, measured in accordance with ASTM D792-13, Method B; (c) melt index measured in accordance with ASTM D1238-13 at 190°C under a load of 2.16 kg (“I₂” or “MI2”) from 0.010 to less than 0.20 g/10 min, (d) flow index measured in accordance with ASTM D1238-13 at 190°C under a load of 21.6 kg (“I21” or “FI21”) from 8.0 to 15 g/10 min, (e) the ratio of melt flow index (FRR) to the flow index (“I₂₁/I₂”) from 100.0 to 800.0, (f) from more than 0 to 14, wt. %, of ethylene-containing chains having a molecular weight (M_W) of more than 0 to 10000 grams per mol (g/mol), based on the total mass of ethylene-containing components in a bimodal PE composition, and (g) the dispersion of molecular weights (Mw/Mn), ĐM is from 7 to 25, measured in accordance with The gel-penetrating chromatography (GPC) test method. A method for obtaining a bimodal polyethylene composition, a product containing a molded form from a bimodal polyethylene composition, a pipe from a bimodal polyethylene composition and a method for transporting a substance through the internal volume of such a pipe are also described.

EFFECT: bimodal PE composition according to the present invention is characterized by at least one improved property, such as greater resistance to slow crack growth (PENT test method), reduced hydrostatic fracture and/or increased manufacturability.

14 cl, 4 dwg, 2 tbl, 3 ex

Description

Technical field

The field includes bimodal polyethylene, polyethylene compositions containing it, products made from them, methods for their manufacture and use, and products containing them.

State of the art

Polyethylene polymers have numerous commercial applications. These include films, sheets, molded products and extruded products. Films and sheets are used in packaging applications and non-packaging applications. Examples are agricultural film, food packaging, clothing bags, grocery bags, heavy duty bags, industrial protective covers, pallets and shrink films and bags. Injection molded products include buckets, freezer containers, lids and toys. Extruded articles include pipes and electrical cable coating layers.

High Temperature Resistant Polyethylenes ("PE-RT") is a class of polyethylene polymers defined in ISO-1043-1 for use in high temperature and industrial piping applications such as pipes for transporting hot or cold water. Typically, PE-RT polymers have a molecular structure and crystalline microstructure that provide hydrostatic pressure strength at high temperatures without the need for crosslinking.

Some polyethylenes are mentioned in US 2005/0054790 A1; US 2015/0017365A1; US 7250473 B2 and US 9017784 B2.

Document US 2005/0054790 A1, S. Mawson et al. relates to a polymerization process, polymerization catalyst compositions, and methods for introducing catalyst compositions into a polymerization reactor. Also to processes for preparing a slurry or solution of a catalyst component and catalyst compositions. Also to methods for controlling the properties of polymer products using catalyst compositions and polymers derived from them.

US 2015/0017365 A1 issued by B-KSohn et al. relates to a multimodal polyolefin resin and a molded product derived therefrom. The polyolefin resin satisfies all of the following (1) to (5), (1) a density of 0.934 to 0.963 g/cm ³ ; (2) melt flow index (190°C., condition 2.16 kg load) from 0.01 to 1.0 g/10 min; (3) Mw/Mn 12 to 60 (GPC); (4) at least two peaks appear when measuring the molecular weight of the polyolefin resin using gel permeation chromatography; and (5) the amount of the polyolefin having Mw 10,000 or less exceeds 15 mass percent, and the amount of the polyolefin having Mw 1,000,000 or more exceeds 1.5 mass percent, when measuring the molecular weight of the polyolefin resin by gel permeation chromatography.

Document US 7250473 B2, issued by D. Schramm et al., relates to a polyethylene resin having a multimodal molecular weight distribution, while the specified resin is further characterized in that it has a density in the range from about 0.925 g/cm ³ to about 0.950 g/ cm ³ melt index (I ₂ ) in the range of about 0.05 g/10 min. up to about 5 g/10 min and in that it contains at least one high molecular weight ethylene interpolymer and at least a low molecular weight ethylene polymer, and to a composition containing such a resin. Also to a molded article containing said resin or composition, in particular to a pipe.

Document US 9017784 B2, issued by M. Palmlöf et al., relates to a pipe made from a polyethylene composition containing a polyethylene base resin that contains c. ethylene copolymer as fraction (A) and d. ethylene homo- or copolymer as the fraction (B), wherein the fraction (A) has a lower molecular weight than the fraction (B), while the polyethylene-based resin can be obtained in a polymerization process in which at least one of the fractions (A) and (B) uses a single site catalyst and the base resin has (i) a density of less than 0.940 kg/m3, and (ii) and an MFR ₅ at 190°C/5.00 kg of at least at least 0.20 g/10 min., and the polyethylene composition has a time to failure of at least 250 hours, measured according to ISO 1167 at 95°C and 4.3 MPa.

The essence of the invention

We have discovered a problem that is detrimental to the manufacture, use and performance of prior polyethylene (PE) compositions consisting of a prior metallocene catalyzed PE ("preceding MCN-PE") and a prior PE made with a Ziegler-Natta catalyst ("preceding MCN-PE"). ZN-PE"). For example, their heat resistance, measured at elevated temperature and tensile stress or pressure, may not be satisfactory for use in PE-RT applications.

The technical solution to this problem was not obvious from the prior art. The problem to be solved with ingenuity is to discover a new PE composition that has improved PE-RT performance. Such a new PE composition would be useful in PE-RT applications.

Our solution to this problem includes a bimodal polyethylene composition ("bimodal PE composition") made using the bimodal catalyst system described below, in which the bimodal PE composition contains from more than 0 to 14 mass percent (wt.%) of ethylene-containing chains having a formula molecular weight (MW) of greater than 0 to 10,000 grams per mole (g/mol) based on the total weight of the ethylene-containing components in the bimodal PE composition. The technical solution also provides products made from them, methods for their manufacture and use, and products containing them.

The inventive bimodal PE composition can be used in a number of industrial applications, including pipes.

Drawings

Fig. 1 - contains drawings of structural formulas of (pro)catalysts.

Fig. 2 is a GPC (Gel Permeation Chromatography) chromatogram from Example 1 of a bimodal PE composition of the present invention.

Fig. 3 is a GPC chromatogram from Example 2 of a bimodal PE composition of the present invention.

Fig. 4 is a plot of dynamic viscosity versus frequency of Examples 1 and 2 of the present invention compared to Monomodal Comparative Example 1.

Detailed description of the invention

The summary and abstract are incorporated herein by reference.

Surprisingly, the bimodal PE composition of the present invention may have at least one improved property, such as, for example, increased resistance to slow crack growth (PENT test method), reduced hydrostatic failure, and/or improved processability. The bimodal PE composition of the present invention can be used to make pipes, films, sheets, extruded products and injection molded products.

Some embodiments of the present invention are described below as numbered aspects for easy cross reference. Additional implementation options are described elsewhere in this document.

Aspect 1: A bimodal polyethylene composition comprising a lower molecular weight (LMW) polyethylene component and a higher molecular weight (HMW) polyethylene component, wherein the LMW and HMW polyethylene components each contain ethylene-derived monomer units and comonomer units. derived from (C ₃ -C ₂₀ )alpha-olefins; and wherein the bimodal polyethylene composition is characterized by each of the constraints of (a) to (f): (a) the resolved bimodality (permitted molecular weight distribution) shown on a Gel Permeation Chromatography (GPC) chromatogram of the bimodal polyethylene composition, where the chromatogram shows a peak, representing the HMW polyethylene component, a peak representing the LMW polyethylene component, and a local minimum in the range of Log (molecular weight) ("Log(MW)")) from 3.0 to 7.0 between the peak representing the HMW polyethylene component and the peak representing polyethylene component LMW measured in accordance with the bimodality test method described below; (b) a density of 0.9300 to 0.9500 grams per cubic centimeter (g/cm ³ ), measured in accordance with ASTM D792-13 Method B; (c) melt index measured in accordance with ASTM D1238-13 at 190 degrees Celsius (°C) under a load of 2.16 kg (kg) ("I ₂ " or "MI2") from 0.010 to less than 0.20 grams per 10 minutes (g/10 min.); (d) flow index measured in accordance with ASTM D1238-13 at 190°C under a load of 21.6 kg ("I ₂₁ " or "FI ₂₁ ") from 8.0 to 15 g/10 min.; (e) a flow rate ratio (FRR) of melt index to flow rate (“I ₂₁ /I ₂ ”) from 100.0 to 800.0; and (f) from more than 0 to 14 wt.% ethylene-containing chains having a formula molecular weight (MW) from more than 0 to 10,000 grams per mole (g/mol), based on the total weight of the ethylene-containing components in the bimodal PE composition. The bimodal polyethylene composition may contain from less than 100.0 to 86% by weight of ethylene-containing chains having a MW of more than 10,000 g/mol. In a bimodal polyethylene composition, the MW of the lightest mass component may differ from embodiment to embodiment, so the expression for MW in (f) as "greater than 0 to 10,000 grams per mole" (i.e., > 0 to 10,000 g/mol) is a clear way to cover all such implementations. The expression "ethylene-containing chains" means macromolecules of ethylene-containing components, which, in turn, are oligomers and/or polymers of ethylene and, optionally, one or more comonomers (eg, alpha-olefins). The ethylene-containing components include the LMW and HMW polyethylene components of the bimodal polyethylene composition. The expression "formula molecular weight" and "MW" mean the same thing and represent the mass of a macromolecule calculated from its molecular formula.

Aspect 2 The bimodal PE composition of aspect 1 is characterized by at least one, alternatively each of the constraints (a) to (f): (a) a local minimum Log(MW) on the GPC chromatogram ranging from 4.0 to 6.0 Log (MW), alternatively 4.5 to 5.5 Log(MW), alternatively 5.0 to 5.5 Log(MW) (e.g. Log(MW) is 5.05 to 5.25) between peak , representing the polyethylene component of the HMW, and a peak representing the polyethylene component of the LMW, measured in accordance with the Bimodality Test Method; (b) a density of 0.931 to 0.9450 g/cm ³ , alternatively 0.9310 to 0.9400 g/cm ³ , alternatively 0.9310 to 0.9390 g/cm ³ , alternatively 0.933 to 0.938 g/ cm ³ alternatively from 0.935 to 0.937 g/cm ³ measured in accordance with ASTM D792-13 Method B; (c) melt index (I ₂ ) 0.010 to 0.10 g/10 min, alternatively 0.045 to 0.095 g/10 min, measured according to ASTM D1238-13 (190° C., 2.16 kg); (d) flow index (I ₂₁ ) from 9 to 14, alternatively from 11 to 13 g/10 min.; (e) a flow ratio (I ₂₁ /I ₂ ) of 110 to 600, alternatively 120 to 400, alternatively 130 to 300, alternatively 150 to 200; and (f) from 7.0 to less than 10.0 wt.%, alternatively from 8.0 to 9.5 wt.% of ethylene-containing chains having MW from more than 0 to 10000 g/mol, based on the total weight of ethylene-containing components in bimodal PE composition.

Aspect 3. The bimodal PE composition of aspect 2 is characterized by at least one, alternatively each of the constraints (a) to (f): (a) a local minimum Log(MW) on the GPC chromatogram ranging from 5.0 to 5.5 Log (MW) between the peak representing the HMW polyethylene component and the peak representing the LMW polyethylene component measured in accordance with the Bimodality Test Method; (b) a density of 0.935 to 0.942 g/cm ³ , alternatively 0.935 to 0.937 g/cm ³ , measured in accordance with ASTM D792-13 Method B; (c) melt index (I ₂ ) from 0.045 to 0.095 g/10 min, measured in accordance with ASTM D1238-13 (190° C., 2.16 kg); (d) flow index (I ₂₁ ) from 9 to 14, alternatively from 11 to 13 g/10 min.; (e) the ratio of flow rates (I ₂₁ /I ₂ ) from 150 to 200; and (f) from 8.0 to 9.5 wt.% ethylene-containing chains having MW from more than 0 to 10,000 g/mol.

Aspect 4 The bimodal PE composition of any of aspects 1-3 is further characterized by any of the limitations of (g) to (l): (g) the molecular weight dispersion (Mw/Mn), ĐM (pronounced D with an M) is between 5 and 30.1, alternatively 7 to 25, alternatively 10.1 to 20.1, all measured according to the Gel Permeation Chromatography (GPC) Test Method described below; (h) no measurable, or alternatively no detectable, number of long chain branches per 1000 carbon atoms (“LCB index”) measured in accordance with the LCB Test Method (described below); (i) the shear thinning index (SHI, η*(10)/η*(200)) is greater than 20, alternatively >20 to 90, alternatively 30 to 80, alternatively 40 to 70, measured according to with the Shear Loss Index Test Method described below; (j) the molecular weight dispersion (Mw/Mn), ĐM, of the LMW polyethylene component is 2.5 to 3.5, alternatively 2.8 to 3.3, alternatively 2.9 to 3.2 after deconvolution of the polyethylene components LMW and HMW bimodal PE composition according to the Deconvolution Test Method described below; and (k) Mw/Mn of the HMW polyethylene component 2.5 to 4.5, alternatively 3.0 to 4.5, alternatively 3.2 to 4.1, alternatively 3.3 to 4.0, all measured in accordance with the GPC Test Method described below, after deconvolution of the LMW and HMW polyethylene components of a bimodal PE composition in accordance with the Deconvolution Test Method described below; (l) each of (g), (i), (j), and (k).

Aspect 5 The bimodal polyethylene composition of any one of aspects 1-4 is further characterized by at least one, alternatively each of the limitations of (i) to (iii): (i) a PENT test result of more than 1000 hours, alternatively more than 2000 hours, measured at °C and 2.4 megapascals (MPa) in accordance with the PENT Test Method described below; (ii) the result of a Hydrostatic Pipe Test greater than 1000 hours, alternatively greater than 2000 hours, measured at 90°C and 3.8 megapascals (MPa) in accordance with Hydrostatic Pipe Test Method 1 described below; and (iii) the result of a Hydrostatic Pipe Test greater than 1000 hours, alternatively greater than 2000 hours, measured at 90°C and 4.0 MPa in accordance with Hydrostatic Pipe Test Method 2 described below. In some aspects, the limits (i) to (iii) are independently a maximum of 20,000 hours, alternatively 10,000 hours, alternatively 5,000 hours.

Aspect 6. The bimodal PE composition of any one of aspects 1-5, wherein the comonomer units derived from (C ₃ -C ₂₀ )alpha-olefins are further described by any of the limitations (i) to (vii): (i) comonomer units derived from (C ₃ -C ₁₀ )alpha-olefins; (ii) comonomer units derived from (C ₄ -C ₁₀ )alpha-olefins; (iii) comonomer units derived from (C ₄ -C ₈ )alpha-olefins; (iv) comonomer units derived from 1-butene; (v) comonomer units derived from 1-hexene; (vi) comonomer units derived from 1-octene; and (vii) a combination of any two from (iv) to (vi).

Aspect 7. Bimodal polyethylene composition obtained by copolymerization of ethylene (monomer) and at least one (C ₃ -C ₂₀ )alpha-olefin (comonomer) in a mixture of a bimodal catalyst system and a correction catalyst solution in the presence of gaseous molecular hydrogen (H ₂ ) and optionally an induced condensing agent (ICA) in one, two or more polymerization reactors (eg, one gas phase fluidized bed reactor) under (co)polymerization conditions; wherein, prior to mixing, the correction catalyst solution consists essentially of (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex (procatalyst, e.g. (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)dimethylzirconium) and an inert liquid solvent (e.g. consists essentially of an activator component (e.g., a methylalumoxane component), a bis(2-pentamethylphenylamido)ethyl)amine zirconium complex, and a (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex, all located on a solid support (e.g., hydrophobic colloidal silica) ; and wherein the (co)polymerization conditions include a reaction temperature of 85° to 105°C, alternatively 86° to 99°C, alternatively 89° to 96°C; a molar ratio of gaseous molecular hydrogen to ethylene (H2/C2 molar ratio) from 0.0007 to 0.010, alternatively from 0.0010 to 0.010, alternatively from 0.0011 to 0.009; and a molar ratio of comonomer (Comer) to ethylene (molar ratio Comer/C2) of 0.0005 to 0.02, alternatively 0.0007 to 0.015, alternatively 0.0010 to 0.013. The resulting bimodal PE composition may be a composition according to any of aspects 1-6. The comonomer may be 1-hexene. H ₂ may be present in the reactor(s) at a concentration of from 500 to 1000 parts per million (ppm, wt), alternatively from 600 to 900 ppm, alternatively from 700 to 800 ppm according to gas chromatography (GC ). The ICA may be a (C ₄ -C ₂₀ )alkane such as isopentane.

Aspect 8. A process for producing a bimodal polyethylene composition comprising contacting ethylene (monomer) and at least one (C ₃ -C ₂₀ )alpha-olefin (comonomer) with a mixture of a bimodal catalyst system and a correction catalyst solution in the presence of gaseous molecular hydrogen ( H ₂ ) and an induced condensing agent (ICA) in one, two or more polymerization reactors (eg, one gas phase fluidized bed reactor) under (co)polymerization conditions, resulting in a bimodal polyethylene composition; wherein, prior to mixing, the correction catalyst solution consists essentially of (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex (procatalyst, e.g. (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)dimethylzirconium) and an inert liquid solvent (e.g. consists essentially of an activator component (e.g., a methylalumoxane component), a non-metallocene ligand-group 4 metal complex (e.g., bis(2-pentamethylphenylamido)ethyl)amine-zirconium complex), and a metallocene ligand-group 4 metal complex (e.g. , complex (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium), all of which are located on a solid support (for example, hydrophobic colloidal silicon dioxide); and wherein the (co)polymerization conditions include a reaction temperature of 85° to 105°C, alternatively 86° to 104°C, alternatively 86° to 99°C, alternatively 89° to 96°C; a molar ratio of gaseous molecular hydrogen to ethylene (H2/C2 molar ratio) from 0.0007 to 0.010, alternatively from 0.0010 to 0.010, alternatively from 0.0011 to 0.009; and a molar ratio of comonomer (Comer) to ethylene (molar ratio Comer/C ₂ ) of 0.0005 to 0.02, alternatively 0.0007 to 0.015, alternatively 0.0010 to 0.013. The resulting bimodal PE composition may be a composition according to any of aspects 1-6. The comonomer may be 1-hexene. H ₂ may be present in the reactor(s) at a concentration of 500 to 1000 ppm (ppm, wt), alternatively 600 to 900 ppm, alternatively 700 to 800 ppm according to GC. In an alternative embodiment of aspect 7 or 8, the bimodal catalyst system can be prepared and then fed to the polymerization reactor(s) as a suspension (e.g., slurry) in mineral oil, and the make-up catalyst solution can be prepared and then fed to the polymerization reactor(s). in the form of a solution, for example, in a liquid alkane.

Aspect 9 The bimodal polyethylene composition of aspect 7 or the process of aspect 8 may be further described by any of the limitations of (i) to (vi): (i) wherein the bimodal catalyst system consists essentially of a bis(2-pentamethylphenylamido)ethyl)aminezirconium complex and (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex in their molar ratio from 1.0:1.0 to 5.0:1.0, respectively, alternatively from 1.5:1.0 to 2.5:1.0 , alternatively 2.0:1.0 to 4.0:1.0, 2.5:1.0 to 3.49:1.0, alternatively 2.7:1.0 to 3.3: 1.0, alternatively 2.9:1.0 to 3.1:1.0, alternatively 1.5:1.0, alternatively 2.0:1.0 and a component of methylalumoxane, all of which are sprayed onto a solid carrier; (ii) wherein the bimodal catalyst system further consists primarily of mineral oil and the solid support is hydrophobic fumed silica (eg, fumed silica treated with dimethyldichlorosilane); (iii) where the mixture is a suspension of a bimodal catalyst system in mineral oil and a correction catalyst solution, and where the mixture is pre-prepared and then fed into the polymerization reactor(s); (iv) wherein the correction catalyst solution is prepared by dissolving (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl) zirconium dimethyl in an inert liquid solvent (eg liquid alkane) to form a correction catalyst solution; (v) where the polymerization reactor(s) is a single gas phase fluidized bed reactor and the process is a gas phase polymerization; and (vi) each of (i) - (v). The molar ratio of bis(2-pentamethylphenylamido)ethyl)aminozirconium complex to (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex can be based on the molar ratio of their respective Zr atom contents, which can be calculated from the masses of the ingredients (e.g., the masses of bis(2-pentamethylphenylamido )ethyl)amino zirconiumdibenzyl and (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride) or can be measured analytically.

Aspect 10. A manufactured article comprising a molded bimodal polyethylene composition according to any one of aspects 1-7.

Aspect 11 The article of manufacture of aspect 10 selected from: pipes, films, sheets, extruded articles and injection molded articles. The manufactured article may be a tube, alternatively a film, alternatively a blown film. Films and sheets can be used in packaging applications and non-packaging applications. Examples are agricultural film, food packaging, clothing bags, grocery bags, heavy duty bags, industrial protective covers, pallets and shrink films and bags. Injection molded products include buckets, freezer containers, lids and toys. Extruded articles include pipes and electrical cable coating layers.

Aspect 12. A pipe comprising a bimodal PE composition according to any one of aspects 1-7 and 9 and defining an internal volumetric space through which a substance can be transported. The pipe may be cylindrical in shape and have a cylindrical wall defining an internal volumetric space through which a substance can be transported.

Aspect 13. The method of transporting a substance, including the movement of a substance through the internal volume of the pipe according to aspect 12. The transported substance can be a fluid medium, such as a gas, vapor, liquid, slurry, or a combination of any two of them. For example, the substance may be water. In some aspects, the transported water may be at a temperature of from 1° to 99°C.

The bimodal PE composition may contain residue or by-products formed from the bimodal catalyst system and the correction catalyst solution used to form the bimodal PE composition. The bimodal polyethylene composition may optionally have zero, one, two or more optional components. Examples of optional components are additives such as colorants, antioxidants, processing aids (for polymer processing), lubricants, oxygen scavengers, chlorine scavengers, compounds resistant to water extraction, and metal deactivators. In some aspects, the bimodal PE composition of any of aspects 1-7 and 9 (i) is prepared by a polymerization process that does not contain a Ziegler-Natta catalyst, (ii) does not contain titanium, or (iii) both (i) and (ii). For example, the method of aspect 8 does not contain a Ziegler-Natta catalyst and the bimodal PE composition thus obtained does not contain titanium.

10000. A number equal to 1.0000x10 ⁴ , alternatively 10,000.0.

Activator (for activation of procatalysts to form catalysts). Also known as a cocatalyst. Any metal-containing compound, material, or combination of compounds and/or substances, whether or not retained on a carrier material, that can activate a pronatalistic agent to produce a catalyst and an activator component. Activation may include, for example, cleavage of at least one leaving group (for example, at least one X in any of the structural formulas in Fig. 1) from the procatalyst metal (for example, M in any of the structural formulas in Fig. 1) to obtain catalyst. A catalyst can be generically named by replacing the leaving group portion of the procatalyst name with "complex". For example, a catalyst obtained by activating bis(2-pentamethylphenylamido)ethyl)aminozirconiumdibenzyl may be referred to as "bis(2-pentamethylphenylamido)ethyl)aminozirconium complex". The catalyst obtained by activating (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride or (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl can be called "(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex". The catalyst obtained by activation of (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride may be the same or different from the catalyst obtained by activation of (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl. The activator metal is generally different from the procatalyst metal. The molar ratio of the metal content of the activator to the metal content of the procatalyst(s) may be from 1000:1 to 0.5:1, alternatively from 300:1 to 1:1, alternatively from 150:1 to 1:1. The activator may be a Lewis acid, a non-coordinating ionic activator or an ionizing activator, or a Lewis base, an aluminum alkyl, or an alkylalumoxane. The alkylaluminum may be a trialkylaluminum, an alkylaluminum halide or an alkylaluminum alkoxide (diethylaluminum ethoxide). The trialkylaluminum may be trimethylaluminum, triethylaluminum ("TEAl"), tripropropylaluminum, triisobutylaluminum, and the like. The alkyl aluminum halide may be diethyl aluminum chloride. The alkylalumoxane may be methylalumoxane (MAO), ethylalumoxane or isobutylaluminumoxane. The activator may be MAO, which is modified methylalumoxane (MMAO). Suitable activator components may be Lewis acid derivatives, non-coordinating ionic activator, ionizing activator, Lewis bases, alkylaluminum or alkylalumoxane, respectively. Activator components may have a structure or composition different from the activator from which they are derived and may be a by-product of procatalyst activation or a by-product derivative. An example of a by-product derivative is the methylalumoxane component, which is formed by the removal of volatiles during spray drying of a bimodal catalyst system made with methylalumoxane. The activator may be commercially available. The activator may be fed to the polymerization reactor(s) (e.g., a single gas-phase fluidized bed reactor) as a separate stream from the feedstock of the reactants used to form the bimodal catalyst system (e.g., the supported bimodal catalyst system) and/or the correction catalyst solution. The activator may be fed to the polymerization reactor(s) in a "wet" mode as a solution thereof in an inert liquid such as mineral oil or toluene, in a slurry mode as a slurry, or in a dry mode as a powder.

Bimodal. Having at least 2, but not limited to 2, peaks in a molecular weight distribution (MWD), such as MWD measured by gel permeation chromatography (GPC). Also known as multimodal. In some aspects there are 2 or 3 peaks, alternatively only 2 peaks in MWD.

bimodal catalytic system. A combination of two or more catalyst compounds independently used to increase the rate of polymerization of the same olefin monomer and/or comonomer and yield a bimodal polyethylene composition. In some aspects, the bimodal catalyst system has only two catalysts and is made from two and only two procatalyst compounds. One of the catalyst compounds may be a metallocene catalyst compound and the other a non-metallocene catalyst compound. One of the catalyst compounds under (co)polymerization conditions produces a lower molecular weight polyethylene component (LMW) and the other catalyst compound produces a higher molecular weight polyethylene component (HMW). The polyethylene components LMW and HMW together constitute a bimodal polyethylene composition, which may be a polyethylene composition of the present invention made with a bimodal catalyst system and having a multimodal (eg, bimodal) molecular weight distribution. Generally, the bimodal catalyst system, the process using it, and the bimodal PE composition of the present invention are free of the Ziegler-Natta catalyst and any residues or by-products thereof.

A bimodal catalyst system can be obtained by contacting at least two procatalysts having different structures from each other with at least one of the activators. Each procatalyst may independently contain a metal atom, at least one ligand associated with the metal atom, and at least one leaving group associated with and displaceable from the metal atom. Each metal may be an element of any of Groups 3 to 14, for example, a Group 4 metal. Each leaving group is H, an unsubstituted alkyl, aryl, aralkyl, halogen, alkoxy, or primary or secondary amino group. In metallocenes, at least one ligand is a cyclopentadienyl or substituted cyclopentadienyl group. In non-metallocenes, no ligand is a cyclopentadienyl or substituted cyclopentadienyl group, but instead at least one ligand has at least one O, N and/or P atom that is coordinated to a metal atom. Typically, the non-metallocene ligand(s) have at least two O, N, and/or P atoms that are coordinated in a multidentate (eg, bidentate or tridentate) mode of binding to the metal atom. Discrete structures mean that the procatalysts and the catalysts derived from them have different ligands and the same or different metal atoms, as well as either the same or different leaving groups.

One of the procatalysts suitable for producing a bimodal catalyst system catalyst and/or for producing a correction catalyst solution may be a metallocene compound of any of formulas (I) to (IX), and another of the procatalysts may be a non-metalocene of any of formulas (A) and ( B), where the formulas are shown in FIG. 1.

In formula (I), fig. 1, each of the groups from R ¹ to R ¹⁰ independently represents H, (C ₁ -C ₂₀ )alkyl, (C ₆ -C ₂₀ )aryl or (C ₇ -C ₂₀ )aralkyl group; M is a Group 4 metal; and each X is independently H, a halide, a (C ₁ -C ₂₀ )alkyl or (C ₇ -C ₂₀ )aralkyl group. In some aspects, each of R ⁷ -R ¹⁰ represents H in formula (I).

In formula (II), fig. 1, each of the groups R ¹ -R ⁶ independently represents H, (C ₁ -C ₂₀ )alkyl, (C ₆ -C ₂₀ )aryl or (C ₇ -C ₂₀ )aralkyl group; M is a Group 4 metal (eg Ti, Zr or Hf); and each X is independently H, a halide, a (C ₁ -C ₂₀ )alkyl or (C ₇ -C ₂₀ )aralkyl group.

In formula (III), fig. 1, each of the groups R ¹ -R ¹² independently represents H, (C ₁ -C ₂₀ )alkyl, (C ₆ -C ₂₀ )aryl or (C ₇ -C ₂₀ )aralkyl group, where at least one of R ⁴ -R ⁷ is not H; M is a Group 4 metal (eg Ti, Zr or Hf); and each X is independently H, a halide, a (C ₁ -C ₂₀ )alkyl or (C ₇ -C ₂₀ )aralkyl group. In some aspects, each of R ⁹ -R ¹² represents H in formula (III).

In some aspects, each X in formulas (I) - (III) independently represents a halide, (C ₁ -C ₄ )alkyl or benzyl; alternatively Cl or benzyl. In some aspects, each halide in formulas (I) - (III) is independently Cl, Br, or I; alternatively Cl or Br; alternatively Cl. In some aspects, each M in formulas (I) - (III) independently represents Ti, Zr or Hf; alternatively Zr or Hf; alternatively Ti; alternatively Zr; alternatively hf.

In formulas (IV) - (IX), fig. 1, Me is methyl (CH ₃ ), Pr is propyl (ie, CH ₂ CH ₂ CH ₃ ), and each “l” substituent on the ring is a methyl group.

In formulas (A) and (B), Fig. 1, M represents a Group 3-12 transition metal atom or a main Group 13 or 14 metal atom, or a Group 4, 5 or 6 metal atom. M may be a Group 4 metal atom, alternatively Ti, Zr or Hf; alternatively Zr or Hf; alternatively Zr. Each X is independently a leaving group as described above, such as an anionic leaving group. The subscript y is 0 or 1; if y is 0, there is no group L'. The subscript n represents the formal oxidation state of the metal atom M and is equal to +3, +4 or +5; alternatively n is +4. L is a Group 15 or 16 element such as nitrogen or oxygen; L' is a Group 15 or 16 element or a Group 14 containing group such as carbon, silicon or germanium. Y is a Group 15 element such as nitrogen or phosphorus; alternatively nitrogen. Z is a group 15 element such as nitrogen or phosphorus; alternatively nitrogen. The subscript m is 0, -1, -2, or -3; alternatively -2; and represents the total formal charge of Y, Z and L in formula (A) and the total formal charge of Y, Z and L' in formula (B). R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ independently represent H, (C ₁ -C ₂₀ )hydrocarbyl group, (C ₁ -C ₂₀ )heterohydrocarbyl group or (C ₁ -C ₂₀ ) an organoheteryl group, wherein the (C ₁ -C ₂₀ )heterohydrocarbyl group and the (C ₁ -C ₂₀ )organoheteryl group each independently have at least one heteroatom selected from Si, Ge, Sn, Pb, or P. Alternatively, R ¹ and R ² are covalently bonded to each other to form a divalent group of formula -R ^1a --R ^2a - and/or R ⁴ and R ⁵ are covalently bonded to each other to form a divalent group of formula -R ^4a -R ^5a - where -R ^1a --R ^2a and -R ^4a -R ^5a - independently represent a (C ₁ -C ₂₀ )hydrocarbylene group, (C ₁ -C ₂₀ )heterohydrocarbylene group or (C ₁ -C ₂₀ )organoheterylene group. R ³ may be absent; alternatively, R ³ is H, a halogen atom, a (C ₁ -C ₂₀ ) hydrocarbyl group, a (C ₁ -C ₂₀ ) heterohydrocarbyl group, or a (C ₁ -C ₂₀ ) organoheteryl group. R ³ is absent if, for example, L is O, H or an alkyl group. R ⁴ and R ⁵ may be a (C ₁ -C ₂₀ )alkyl group, a (C ₆ -C ₂₀ )aryl group substituted with a (C ₆ -C ₂₀ )aryl group, a (C ₃ -C ₂₀ )cycloalkyl group substituted a (C ₃ -C ₂₀ )cycloalkyl group, a (C ₈ -C ₂₀ ) bicyclic aralkyl group, or a substituted (C ₈ -C ₂₀ ) bicyclic aralkyl group. R ⁶ and R ⁷ may be H or absent. R* may be absent or may be hydrogen, a group containing a Group 14 atom, a halogen, or a group containing a heteroatom.

In some aspects, the bimodal catalyst system may comprise a combination of a metallocene catalyst compound and a non-metallocene catalyst compound. The metallocene catalyst compound may be a metallocene ligand-metal complex, such as a Group 4 ligand-metal metallocene complex, which can be prepared by activating (with an activator) a procatalyst compound selected from (pentamethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride, bis(n -butylcyclopentadienyl)zirconium dichloride, (pentamethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconiumdimethyl and bis(n-butylcyclopentadienyl)zirconiumdimethyl. The non-metallocene catalyst compound may be a non-metallocene ligand-metal complex, such as a Group 4 non-metallocene ligand-metal complex, which can be prepared by activating (with an activator) a procatalyst compound selected from bis(2-(2,4,6-trimethylphenylamido) ethyl)amine zirconium dibenzyl; and bis (2-(pentamethylphenylamido)ethyl) amine zirconium dibenzyl.

In some aspects, a bimodal catalyst system can be obtained by activating, in accordance with the method of contacting with an activator, a combination of a metallocene procatalyst compound that is (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride and a non-metallocene procatalyst compound that is bis(2 -pentamethylphenylamido)ethyl)aminezirconiumdibenzyl. (Tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride is a compound of formula (II) wherein M is Zr, each X is Cl, R ⁶ is propyl (CH ₂ CH ₂ CH ₃ ) and each R ¹ -R ⁴ is methyl. Bis(2-pentamethylphenylamido)ethyl)aminezirconiumdibenzyl is a procatalyst compound of formula (A) wherein M is Zr, each X is benzyl, R ¹ and R ² are each CH ₂ CH ₂ ; R ³ is H; L, Y and Z are all N; and R ⁴ and R ⁵ are each pentamethylphenyl; and R ⁶ and R ⁷ are absent.

Each of the catalyst compounds of the bimodal catalyst system may independently be not supported, alternatively supported on a support material, in this latter case the bimodal catalyst system is a supported catalyst system. When each catalyst compound is supported, the catalyst compounds may be on the same support material (eg, on the same particles) or on different support materials (eg, on different particles). The bimodal catalyst system comprises unsupported mixtures of catalyst compounds in suspension and/or solution form. The carrier material can be silica (eg colloidal silica), alumina, clay or talc. Colloidal silica may be hydrophilic (untreated), alternatively hydrophobic (treated). In some aspects, the carrier is hydrophobic fumed silica, which can be obtained by treating untreated fumed silica with a treating agent such as dimethyldichlorosilane, polydimethylsiloxane fluid, or hexamethyldisilazane. In some aspects, the treating agent is dimethyldichlorosilane.

In some aspects, the bimodal catalyst system is the bimodal catalyst system described in any of the following references: US 7193017 B2; US 7312279 B2; US 7858702 B2; US 7868092 B2; US 8202940 B2; and US 8378029 B2 (eg col 4/line 60 - col 5/line 10 and col 10/lines 6 - 38 and Example 1).

The bimodal catalyst system can be fed to the polymerization reactor(s) in a "dry mode" or "wet mode", alternatively in a dry mode, alternatively in a wet mode. In the dry mode, the feed is carried out in the form of a dry powder or granules. In wet mode, the feed is carried out as a suspension of the bimodal catalyst system in an inert liquid such as mineral oil. The bimodal catalyst system is commercially available under the name PRODIGY™ BimodalCatalysts, such as BMC-200, from Univation Technologies, LLC.

(C ₃ -C ₂₀ ) alpha-olefin. The compound of formula (I): H ₂ C=C(H)-R (I), where R represents a (C ₁ -C ₁₈ )straight chain alkyl group. A (C ₁ -C ₁₈ )alkyl group is a monovalent unsubstituted saturated hydrocarbon having 1 to 18 carbon atoms. Examples of R are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl. In some embodiments, the (C ₃ -C ₂₀ )alpha-olefin is 1-propene, 1-butene, 1-hexene, or 1-octene; alternatively 1-butene, 1-hexene or 1-octene; alternatively 1-butene or 1-hexene; alternatively 1-butene or 1-octene; alternatively 1-hexene or 1-octene; alternatively 1-butene; alternatively 1-hexene; alternatively 1-octene; alternatively a combination of any two of 1-butene, 1-hexene and 1-octene. The (C ₃ -C ₂₀ ) alpha olefin which is used as the comonomer from which the comonomer units of the LMW polyethylene component are formed may be the same or alternatively different from the (C ₃ -C ₂₀ ) alpha olefin from which the comonomer units are formed. links of the polyethylene component HMW.

Consisting essentially of, consists essentially of, and the like. Partially closed expressions that exclude anything that might affect the main and new characteristics of what they describe, but otherwise allow everything else. When used to describe an embodiment of a bimodal catalyst system consisting essentially of bis(2-pentamethylphenylamido)ethyl)aminedibenzylzirconium and (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride, both located on a solid support and activated with an activating agent, the expression means that the embodiment is not contains a Ziegler-Natta catalyst or any organic ligand other than bis(2-pentamethylphenylamido)ethyl)amine, benzyl, tetramethylcyclopentadienyl and n-propylcyclopentadienyl ligand. One or more benzyl and chloride leaving groups may be absent from Zr in the bimodal catalyst system. The expression "consisting essentially of" when used to describe "correct catalyst solution" means that the correction catalyst solution is not supported (i.e., not on a particulate solid) and does not contain a Ziegler-Natta catalyst or any organic ligand other than tetramethylcyclopentadienyl and n-propylcyclopentadienyl ligands. The expression "consists essentially of" when applied to dry inert purge gas means that the dry inert purge gas does not contain, alternatively has less than 5 parts per million, based on total mass by mass of gas, of water or any reactive compound that can oxidize the component real polymerization reaction. In some aspects, any, alternatively, each "comprising" or "comprises" can be replaced by "consisting essentially of" or "consists essentially of" respectively; alternatively, "consisting of" or "consists of", respectively.

Consisting of and consists of. Closed expressions that exclude anything not specifically described by the constraint it modifies. In some aspects, any, alternatively, each expression "essentially consisting of" or "essentially consists of" can be replaced by the expression "consisting of" or "consists of", respectively.

(co)polymerization conditions. Any variable or combination of such variables that affects the result, such as the composition of the catalyst; amount of reagent; the molar ratio of the two reactants; no interfering materials (eg H ₂ O and O ₂ ); or a process parameter (eg, feed rate or temperature), step, or sequence that is effective and beneficial to the copolymerization process of the present invention in the polymerization reactor(s) to produce the bimodal PE composition of the present invention.

At least one, alternatively, each of the (co)polymerization conditions may be fixed (ie unchanged) during the production of the bimodal PE composition of the present invention. Such fixed (co)polymerization conditions may be referred to herein as stationary (co)polymerization conditions. Stationary (co)polymerization conditions are useful for continuous production embodiments of the bimodal PE composition of the present invention having the same polymer properties.

Alternatively, at least one, alternatively, two or more of the (co)polymerization conditions may be changed within their defined operating parameters during the production of the bimodal PE composition of the present invention in order to transition from the production of the first embodiment of the bimodal PE composition of the present invention, having a first set of polymer properties to a second embodiment of a bimodal PE composition of the present invention having a second set of polymer properties, wherein the first and second sets of polymer properties are different and are each within the limitations described herein for the bimodal PE composition of the present invention . For example, other things being equal (co)polymerization conditions, a higher molar ratio of (C ₃ -C ₂₀ )alpha-olefin comonomer/ethylene feed in the copolymerization process of the present invention results in a lower product density of the bimodal PE composition of the present invention. At a given comonomer/ethylene molar ratio, the molar ratio of procatalyst of the correction catalyst solution relative to the total moles of catalyst compounds of the bimodal catalyst system can be varied to control density, melt index, flow index, molecular weight, and/or melt flow ratio. To illustrate the transition approach, run one of the copolymerization examples of the present invention described below to achieve stationary (co)polymerization conditions. Then change one of the (co)polymerization conditions to start producing a new version of the bimodal PE composition of the present invention. Take a sample of the new variant and measure its property. If necessary, repeat the change condition/product sampling/property measurement steps at intervals until the measurement indicates that the desired value for the property is obtained. An example of such a change in operating parameter includes changing the operating temperature within the aforementioned range of 85°C to 100°C, for example by changing from a first operating temperature of 90°C to a second operating temperature of 95°C, or by changing from a third operating temperature of 95°C to the fourth operating temperature of 90°C. Similarly, another example of changing the operating parameter involves changing the molar ratio of molecular hydrogen to ethylene (H2/C2) from 0.0011 to 0.0013, or from 0.0012 to 0.0011. Similarly, another example of changing the operating parameter involves changing the molar ratio of comonomer (Comer) to ethylene (molar ratio Comer/C2) from 0.011 to 0.014, or from 0.014 to 0.011. Combinations of two or more of the above illustrative variations are included herein. The transition from one set to another set of (co)polymerization conditions is allowed within the meaning of "(co)polymerization conditions", as long as the operating parameters of both sets of (co)polymerization conditions are within the limits defined for them in this document. An advantageous consequence of the transition described above is that any described property value for the bimodal PE composition of the present invention, or its LMW or HMW polyethylene component, can be achieved by a person skilled in the art in view of the ideas set forth herein.

The (co)polymerization conditions may further include a high pressure, liquid phase or gas phase polymerization reactor and a polymerization process for producing the bimodal PE composition of the present invention. Such reactors and methods are generally well known in the art. For example, a liquid phase polymerization reactor/method may be in a solution phase or a slurry phase, as described in US 3,324,095. ; US 4588790; US 4994534; US 5352749; US 5,462,999 and US 6,489,408. The gas phase polymerization reactor/process may be a fluidized bed reactor/process as described in US 3,709,853; US4003712; US 4011382; US 4302566; US 4543399; US 4,882,400; US 5352749; US 5541270; EP-A-0 802 202 and Belgian Patent No. 839380. These patents disclose gas phase polymerization processes in which the polymerization medium is either mechanically agitated or fluidized by a continuous flow of gaseous monomer and diluent. Other contemplated gas phase processes include sequential or multi-stage polymerization processes such as those described in US 5,627,242; US5665818; US5677375; EP-A-0 794 200; EP-B1-0 649 992; EP-A-0 802 202 and EP-B-634421.

The (co)polymerization conditions for gas phase or liquid phase reactors/processes may further include one or more additives such as a chain transfer agent, promoter or scavenger. Chain transfer agents are well known and may be alkyl metals such as diethyl zinc. Promoters are well known, for example in US 4988783, and may include chloroform, CFCl3, trichloroethane and difluorotetrachloroethane. The scavengers may be trialkylaluminum. Suspension or gas phase polymerizations can be carried out without (deliberately added) scavengers. The (co)polymerization conditions for gas phase reactors/polymerizations may additionally include some (e.g., 0.5 to 200 ppm based on total reactor feed) static control agents and/or continuity additives such as aluminum stearate or polyethyleneimine. Static control agents may be added to the gas phase reactor to inhibit the formation or accumulation of static charge therein.

The (co)polymerization conditions may further include the use of molecular hydrogen to control the final properties of the LMW and/or HMW polyethylene components or bimodal PE composition of the present invention. Such use of H ₂ is generally described in Polypropylene Handbook 76-78 (HanserPublishers, 1996). Other things being equal, the use of hydrogen can increase the melt index (MI) or flow index (FI), while MI or FI is affected by the concentration of hydrogen. The molar ratio of hydrogen to total monomer (H ₂ /monomer), hydrogen to ethylene (H ₂ /C ₂ ) or hydrogen to comonomer (H ₂ /α-olefin) can be from 0.0001 to 10, alternatively from 0.0005 to 5, alternatively 0.001 to 3 0.001 to 0.10.

The (co)polymerization conditions may include the partial pressure of ethylene in the polymerization reactor(s) independently from 690 to 3450 kilopascals (kPa, from 100 to 500 pounds per square inch absolute (psi abs.), alternatively from 1030 to 2070 kPa (150 to 300 psig), alternatively 1380 to 1720 kPa (200 to 250 psig), alternatively 1450 to 1590 kPa (210 to 230 psig) 1520 kPa (220 psi abs.) 1000 psi abs = 6.8948 kPa.

Dry. Typically, the moisture content is from 0 to less than 5 parts per million, based on all parts by weight. The materials fed into the polymerization reactor(s) during the polymerization reaction under (co)polymerization conditions are usually dry.

Ethylene. Compound of formula H ₂ C=CH ₂ . polymerizable monomer.

Submitted materials. The amounts of reactants and/or reactants that are added or "feed" to the reactor. In the continuous polymerization mode, each feed can independently be continuous or intermittent. Amounts or "feeds" can be measured, for example, by dosing, to control the amounts and relative amounts of various reactants and reagents in the reactor at any given time.

Film: For the purposes of the application, properties were measured on single layer films 25 micrometers thick.

Higher molecular weight (HMW). Relative to LMW, having a higher weight average molecular weight (Mw). The HMW polyethylene component of the bimodal PE composition of the present invention may have a Mw of 10,000 to 1,000,000 g/mol. The lower limit point Mw for the HMW polyethylene component may be 20,000, alternatively 50,000, alternatively 100,000, alternatively 150,000, alternatively 200,000, alternatively 250,000, alternatively 300,000 g/mol. The upper limit point Mw may be 900,000, alternatively 800,000, alternatively 700,000, alternatively 600,000 g/mol. In describing the bimodal PE composition of the present invention, the lower Mw range for the HMW polyethylene component may overlap the upper Mw range for the LMW polyethylene component, provided that in any embodiment of the bimodal PE composition of the present invention, the specific Mw for the HMW polyethylene component is greater than than the specific Mw for the LMW polyethylene component. The HMW polyethylene component can be produced with a catalyst obtained by activating a Group 4 non-metallocene ligand-metal complex.

Inert. In general, not (noticeably) reactive or not (noticeably) disruptive of the polymerization reaction of the present invention. The expression "inert" when applied to the purge gas or ethylene supply means a molecular oxygen (O ₂ ) content of 0 to less than 5 ppm based on all parts by weight of the purge gas or ethylene supply.

Induced Condensing Agent (ICA). An inert liquid used to cool materials in a polymerization reactor(s) (eg, a fluidized bed reactor). In some aspects, ICA is (C ₅ -C ₂₀ )alkane, alternatively (C ₁₁ -C ₂₀ )alkane, alternatively (C ₅ -C ₁₀ )alkane. In some aspects, ICA is a (C ₅ -C ₁₀ )alkane. In some aspects, the (C ₅ -C ₁₀ )alkane is pentane, such as normal pentane or isopentane; hexane; heptane; octane; nonane; dean, or a combination of any two or more of them. In some aspects, the ICA is isopentane (ie, 2-methylbutane). The polymerization process of the present invention that uses ICA may be referred to herein as induced condensation mode operation (ICMO). The gas phase concentration was measured using gas chromatography by calibrating the peak area percent to mole percent (mol %) with a gas mixture standard with known concentrations of the respective gas phase components. The concentration may be from 1 to 10 mol.%, alternatively from 3 to 8 mol.%.

Lower molecular weight (LMW). Relative to HMW, having a lower weight average molecular weight (Mw). The polyethylene component LMW of the bimodal PE composition of the present invention may have a Mw of 3,000 to 100,000 g/mol. The lower limit point Mw for the polyethylene component LMW may be 5000, alternatively 8000, alternatively 10000, alternatively 12000, alternatively 15000, alternatively 20000 g/mol. The upper limit point Mw may be 50,000, alternatively 40,000, alternatively 35,000, alternatively 30,000 g/mol. The LMW polyethylene component can be produced with a catalyst obtained by activation of a Group 4 metallocene ligand-metal complex. As mentioned above, the bimodal PE composition has a maximum of more than 0 to 14 wt. based on the total weight of the polyethylene polymers in the bimodal PE composition.

Polyethylene. Macromolecule or set of macromolecules consisting of repeating units, in which from 50 to 100 mol.%, alternatively from 70 to 100 mol.%, alternatively from 80 to 100 mol.%, alternatively from 90 to 100 mol.%, alternatively from 95 up to 100 mol%, alternatively any of the above ranges in which the upper limit point is <100 mol%, such repeat units are derived from ethylene monomer, and, in aspects in which less than 100 mol% ethylene repeat units are present, the remainder repeating units are comonomer units derived from at least one (C ₃ -C ₂₀ )alpha-olefin; or a collection of such macromolecules. Low density polyethylene (LDPE): typically having a density of 0.910 to 0.940 g/cm ³ measured in accordance with ASTM D792-13, Method B. In some aspects, the bimodal PE composition is a bimodal LDPE composition, alternatively a bimodal linear low density polyethylene composition ( LLDPE). LLDPE: typically has a density of 0.910 to 0.940 g/cm ³ measured in accordance with ASTM D792-13 Method B and a substantially linear backbone structure.

Procatalyst. Also called a precatalyst or catalyst compound (as opposed to an active catalyst compound), usually a material, compound, or combination of compounds that exhibits no or extremely low polymerization activity (e.g., catalyst efficiency can be between 0 or <1000) in the absence of an activator, but after activation with an activator, provides a catalyst that exhibits a catalytic efficiency at least 10 times greater than, if any, that of the pronatalistic.

Resolved (GPC chromatogram). A molecular weight distribution that has two peaks separated by an intermediate local minimum. For example, the resolved GPC chromatogram of the polymers of the present invention, represented by a plot of dW/dLog(MW) versus Log(MW), which shows the local maximum values dW/dLog(MW) for the peaks of the polyethylene components LMW and HMW and the value of the local minimum dW/ dLog(MW) at Log(MW) between peaks. At least some separation of the peaks for the polyethylene components LMW and HMW in the GPC chromatogram. As a rule, the division cannot be up to the baseline.

Starting or restarting the polymerization reactor(s), illustrated by a fluidized bed reactor. Starting a recommissioned fluidized bed reactor (cold start) or restarting a fluidized bed reactor in a transitional state (warm start/transition) includes a period of time that precedes the achievement of (co)polymerization conditions. Starting or restarting may include the use of a seed bed, pre-loaded or loaded, respectively, in the fluidized bed reactor. The seed layer may consist of polyethylene powder. The seed layer polyethylene may be PE, alternatively bimodal PE, alternatively a previously manufactured embodiment of the bimodal PE composition of the present invention.

Starting or restarting a fluidized bed reactor may also include gas atmosphere transitions comprising purging air or other unwanted gas(s) from the reactor with dry (anhydrous) inert gas to purge followed by purging dry inert gas to purge out of the reactor with dry ethylene gas. The dry inert purge gas may consist essentially of molecular nitrogen (N ₂ ), argon, helium, or a mixture of any two or more of these. When the fluidized bed reactor is idle, it contains an atmosphere of air prior to start-up (cold start). The dry inert purge gas can be used to remove air from a recommissioned fluidized bed reactor in the early stages of startup to provide a fluidized bed reactor having a dry inert purge atmosphere. Prior to restart (eg, after seed bed changes or before alpha olefin comonomer change), the fluidized bed reactor in the transition state may contain an atmosphere of unwanted alpha olefin, unwanted ICA, or other unwanted gas or vapour. The dry inert purge gas can be used to remove unwanted vapor or gas from the fluidized bed reactor in the transitional state in the early stages of restart to provide a fluidized bed reactor having a dry inert purge atmosphere. Any dry inert purge gas itself can be removed from the fluidized bed reactor with dry ethylene gas. The dry ethylene gas may further comprise molecular hydrogen gas such that the dry ethylene gas is fed to the fluidized bed reactor as a mixture of the two. Alternatively, dry molecular hydrogen gas can be introduced separately and after the fluidized bed reactor atmosphere has been converted to ethylene. Gas atmosphere transitions can be performed before, during or after heating the fluidized bed reactor to the reaction temperature of the (co)polymerization conditions.

Starting or restarting the fluidized bed reactor also includes the introduction of the original reagents and reagents. Reactants include ethylene and alpha-olefin. The reactants fed to the fluidized bed reactor include gaseous molecular hydrogen and an induced condensing agent (ICA), as well as a mixture of a bimodal catalyst system and a correction catalyst solution.

Correction catalyst solution. Any of the metallocene procatalyst compounds or non-metallocene procatalyst compounds described above, dissolved in an inert liquid solvent (eg liquid alkane). The correction catalyst solution is mixed with a bimodal catalyst system to obtain a mixture, and this mixture is used in the polymerization reaction of the present invention to modify at least one property of the thus obtained bimodal PE composition of the present invention. Examples of such at least one property are density, melt index MI2, flow index FI21, flow ratio and molecular weight dispersion (Mw/Mn), ĐM. The mixture of the bimodal catalyst system and the correction catalyst solution can be fed to the polymerization reactor(s) in a "wet mode", alternatively it can be devolatilized and fed in a "dry mode". In the dry mode, the feed is carried out in the form of a dry powder or granules. If the mixture contains a solid carrier, in the wet mode it is served as a suspension or slurry. In some aspects, the inert liquid is a liquid alkane such as heptane.

Ziegler-Natta catalysts. Heterogeneous materials which increase the reaction rates of the polymerization of olefins and are generally products which are obtained by contacting inorganic titanium compounds such as titanium halides supported on a magnesium chloride support with an activator. The activator may be an aluminum alkyl activator such as triethylaluminum (TEA), triisobutylaluminum (TIBA), diethylaluminum chloride (DEAC), diethylaluminum ethoxide (DEAE) or ethylaluminum dichloride (EADC).

As an advantage, we have found the bimodal PE of the present invention. It unexpectedly has at least one improved property, such as, for example, increased (greater) resistance to slow crack growth (PENT test method), reduced hydrostatic failure (eg, increased time to hydrostatic failure), and/or improved processability.

Test samples of embodiments of unfilled and filled compositions can be separately manufactured into injection molded plates. The mechanical properties of these compositions can be characterized using test specimens cut from injection molded plates.

A compound includes all of its isotopes, both naturally occurring and isotopically enriched forms. Enriched forms can be used in medicine or to combat counterfeiting.

In some aspects, any compound, composition, formulation, mixture, or reaction product herein may be free of any of the chemical elements selected from the group consisting of: H, Li, Be, B, C, N, O, F, Na , Mg, Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr , Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au , Hg, Tl, Pb, Bi, lanthanides and actinides; provided that the chemical elements required for the compound, composition, composition, mixture or reaction product (eg C and H required for a polyolefin or C, H and O required for an alcohol) are not excluded.

The following applies unless otherwise noted. Alternatively, a separate embodiment precedes. ASTM means Standards Organization, ASTM International, West Conshohocken, Pennsylvania, USA. IEC means the Standards Organization, International Electrotechnical Commission, Geneva, Switzerland. ISO means the Standards Organization, International Organization for Standardization, Geneva, Switzerland. Any comparative example is used for illustrative purposes only and will not be prior art. Does not contain or absent means complete absence; alternatively not found. IUPAC is the International Union of Pure and Applied Chemistry (IUPAC Secretariat, ResearchTrianglePark, North Carolina, USA). May means a permitted choice, not an imperative. Working means functionally efficient or efficient. Optional (optional) means absent (or excluded), alternatively present (or included). Parts per million are by weight. Properties are measured using a standard test method and measurement conditions (eg viscosity: 23° C. and 101.3 kPa). Ranges include endpoints, subranges, and the integer and/or fractional values included therein, except that the integer range does not include fractional values. Room temperature: 23°C. ± 1°C. Substituted in relation to a compound means the presence of one or more substituents instead of hydrogen, up to and including complete substitution.

Unless otherwise noted, use the following blanks to determine specifications.

Bimodality Test Method: Determine the presence or absence of allowed bimodality by plotting dWf/dLogM (mass detector response) on the y-axis versus LogM on the x-axis to obtain a GPC chromatogram curve containing the local maximum Log(MW) values for the peaks polyethylene components LMW and HMW, and observe the presence or absence of a local minimum between the peaks of the polyethylene components LMW and HMW. DWf is the change in mass fraction, dLogM is also called dLog(MW) and is the change in the logarithm of the molecular weight, and LogM is also called Log(MW) and is the logarithm of the molecular weight.

Deconvolution Test Method: Divide the chromatogram obtained using the Bimodality Test Method into nine (9) Schultz-Flory molecular weight distributions. Such a deconvolution method is described in US6534604. Assign the lowest four MW distributions to the LMW polyethylene component and the highest five MW distributions to the HMW polyethylene component. The respective weight percentages (wt.%) for each of the polyethylene components LMW and HMW in the bimodal polyethylene composition of the present invention are determined using the summed values of the mass fractions (Wf) of the polyethylene components LMW and HMW, and the corresponding number average molecular weights (Mn) and weight average molecular mass (Mw) according to the well-known mathematical processing of the aggregated distributions of MW according to Schultz-Flory.

Density Method: Measured in accordance with ASTM D792-13, Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement Method B (for testing solid plastics in liquids other than water, such as liquid 2-propanol ). The results are expressed in units of grams per cubic centimeter (g/cm ³ ).

Flow Index (190°C, 21.6 kg, "I ₂₁ ") Test Method: Uses ASTMD1238-13, Standard Test Method for Melt Flow Rates of Thermoplastics Using an Extrusion Plastometer Using Conditions of 190°C/21.6 kilograms (kg) . Results are expressed in units of grams elapsed per 10 minutes (g/10 min) or the equivalent in decigrams per 1.0 minute (dg/1 min).

Flow ratios: (190°C, "I ₂₁ /I ₂ ") Method of determination: Calculated by dividing the value from the FI Flow Index Test Method ₂₁ by the value from the Melt Index Test Method I ₂ .

, где нижний индекс «X» обозначает испытуемую пробу, индекс «PS» обозначает стандарты PS,

,

, а ax и

получены из опубликованной литературы. Для полиэтиленов ax/Kx = 0,695/0,000579. Для полипропилена ax/Kx = 0,705/0,0002288. В каждой точке полученной хроматограммы рассчитывают концентрацию c из сигнала DRI с вычтенной базовой линией, IDRI, используя следующее уравнение: c = KDRIIDRI/(dn/dc), где KDRI является постоянной величиной, определенной путем калибровки DRI, / обозначает деление, а dn/dc - приращение показателя преломления для полимера. Для полиэтилена dn/dc = 0,109. Рассчитывают массовую степень извлечения полимера из отношения интегральной площади хроматограммы концентрационной хроматографии по объему элюента и массе закалывания, которая равна предварительно определенной концентрации, умноженной на объем петли ввода. Выражают все молекулярные массы в граммах на моль (г/моль), если не указано иное. Дополнительные подробности, касающиеся способов определения Mw, Mn, MWD, описаны в US 2006/0173123, стр. 24-25, абзацы с [0334] по [0341]. Откладывают dW/dLog(MW) на оси y в зависимости от Log(MW) на оси x с получением хроматограммы GPC, где Log(MW) и dW/dLog(MW) являются такими, как определено выше.Gel Permeation Chromatography (GPC) method: Weight average molecular weight method: Mw, number average molecular weight (Mn), and Mw/Mn are determined using chromatograms obtained with a High Temperature Gel Permeation Chromatography (HTGPC, PolymerLaboratories) apparatus. The HTGPC is equipped with transmission lines, a differential refractive index detector (DRI), and three PolygerLaboratoriesPLgel 10 µmMixed-B columns, all in an oven maintained at 160°C. The method uses a solvent consisting of BHT-treated TCB at a nominal flow rate of 1.0 milliliters per minute (mL/min) and a nominal injection volume of 300 microliters (µL). A solvent is prepared by dissolving 6 g of butylated hydroxytoluene (BHT, antioxidant) in 4 liters (L) of analytical grade 1,2,4-trichlorobenzene (TCB). and filtering the resulting solution through a 0.1 μm (μm) Teflon filter to obtain a solvent. The solvent is degassed with an inline degasser before it enters the HTGPC. Calibrate the columns using a series of monodisperse polystyrene (PS) standards. Separately, known concentrations of test polymer dissolved in solvent are prepared by heating known amounts of it in known volumes of solvent at 160° C. with continuous shaking for 2 hours to obtain solutions. (Measure all amounts gravimetrically.) Target concentrations of solutions, s, of the polymer under test, from 0.5 to 2.0 milligrams of polymer per milliliter of solution (mg/ml), with lower concentrations, s, used for polymers with higher molecular weight. Before testing each sample, purge the DRI detector. Then increase the flow in the instrument to 1.0 ml/min and allow the DRI detector to stabilize for 8 hours before introducing the first sample. Calculate Mw and Mn using universal calibration curves with column calibrations. Calculate the MW for each elution volume using the following equation:

where the subscript "X" denotes the test sample, the subscript "PS" denotes the PS standards,

,

, and ax and

obtained from published literature. For polyethylenes ax/Kx = 0.695/0.000579. For polypropylene ax/Kx = 0.705/0.0002288. At each point in the resulting chromatogram, calculate the concentration c from the baseline-subtracted DRI signal, IDRI, using the following equation: c = KDRIIDRI/(dn/dc), where KDRI is a constant determined by DRI calibration, / denotes division, and dn/ dc is the refractive index increment for the polymer. For polyethylene dn/dc = 0.109. Calculate the mass recovery of the polymer from the ratio of the integral area of the concentration chromatography chromatogram over the eluent volume and the puncture mass, which is equal to the predetermined concentration multiplied by the volume of the inlet loop. All molecular weights are expressed in grams per mol (g/mol) unless otherwise indicated. Additional details regarding methods for determining Mw, Mn, MWD are described in US 2006/0173123, pages 24-25, paragraphs [0334] to [0341]. Plot dW/dLog(MW) on the y-axis versus Log(MW) on the x-axis to obtain a GPC chromatogram where Log(MW) and dW/dLog(MW) are as defined above.

Long Chain Branching (LCB) Test Method: Calculate the number of long chain branches (LCB) per 1000 carbon atoms of the polymer tested using the correlation developed by Janzen and Colby (J. Mol. Struct., 485/486, 569-584 (1999)) between zero shear viscosity, ηο, and Mw. Their correlation is drawn as a control line on the control plot of η _ο on the Y-axis and Mw on the X-axis. The test polymer is then characterized (a) and (b): (a) using the Zero Shear Viscosity Method described below, measuring the vibrational shear the test polymer at low strain (10%) and using a three-parameter empirical Carro-Yasuda model ("CY model") to determine from it the values of η _ο ; and (b) using the GPC Test Method described previously, measuring the Mw of the polymer being tested. Display the results for η _ο and Mw of the tested polymer on the control graph and compare them with the control line. Results for test polymers with zero (0) long chain branching per 1000 carbons will be plotted below the Janzen and Colby control line, while results for test polymers having long chain branching > 0 per 1000 carbons will be plotted above the Janzen and Colby control lines. Colby. The CY model is well known from RB Bird, RC Armstrong, & O. Hasseger, Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, ^2nd Edition, John Wiley & Sons, 1987; CA Hieber & HH Chiang, Rheol. Acta, 1989, 28: 321; and C. A. Hieber & H. H. Chiang, Polym. Eng. sci. 1992, 32:931.

Melt index (190° C., 2.16 kilograms (kg), "I ₂ ") Test method: for an ethylene-based (co)polymer, measured in accordance with ASTM D1238-13 using the conditions of 190° C./2.16 kg, formerly known as "Condition E" and also known as MI ₂ . Results are expressed in units of grams elapsed per 10 minutes (g/10 min) or the equivalent in decigrams per 1.0 minute (dg/1 min). 10.0 dg = 1.00 g. The melt index is inversely proportional to the weight average molecular weight of the polyethylene, although the inverse relationship is not linear. Thus, the higher the molecular weight, the lower the melt index.

Test Method PENT 90°C, 2.4 MPa): ASTMF1473-16, Standard Test Method for Notched Tensile Test for Measuring the Resistance of Polyethylene Pipes and Resins to Slow Crack Growth. Also known as the Pennsylvania Notched Test ("PENT"). Test specimens are prepared from injection molded plates, the specimens are precisely notched, and then the notched specimens are subjected to constant tensile stress at elevated temperature in air.

Hydrostatic Pipe Test Methods 1 and 2 (90°C, 3.8 or 4.0 MPa, respectively): characterized as PE-RTII type material which, when tested in accordance with ISO 9080 or equivalent, with internal pressure tests carried out in according to ISO 1167-1 and ISO 1167-2, the composition of the present invention corresponds to the 4-parameter model given in ISO 24033 for PE-RT type II material over the temperature and internal pressure ranges specified in ISO 22391. Thus, embodiments The bimodal polyethylene composition of the present invention may be referred to herein as high temperature bimodal polyethylene or PE-RT. As a short-term preliminary test ("water in water"), a hydrostatic test, as described in ISO 22391-2, is carried out on pipes composed of the test material in accordance with ISO 24033:2009 under two specific hydrostatic conditions, namely 3.8. MPa and 90°C or 4.0 MPa and 90°C. The test pipes are SDR 11 pipes having a diameter of 1 inch (25.4 mm), a wall thickness of 0.12 inch (3 mm) and a length of 18 inches (457 mm). Pipes are made by extruding a polymer melt at an internal temperature maintained at 204.4°C (400°F) and a polymer feed rate of 130.6 kg/h (288 lb/h) using a model Maplan SS60-30 pipe extruder, having an annular head that defines an opening in the slot. The profile of the molten pipe exiting the annular head is pulled from the slot opening into the inside of the sizing sleeve by a downstream pulling device operating at a pulling speed of 8.1 meters per minute (26.57 feet per minute). As the pipe moves through the calibration sleeve, the vacuum draws the molten pipe profile towards the inside of the sleeve. Cooling water enters the calibration sleeve, cooling the pipe and maintaining the specified dimensions and smooth surface.

Shear Thinning Index (SHI) Test Method: Perform vibrational shear measurements at low stresses (10%) on polymer melts at 190°C using TAInstruments' advanced ARES-G2 rheometric expansion system with parallel plate geometry to obtain storage modulus (G '), loss modulus (G"), complex modulus (G*), and complex viscosity (η*) as a function of frequency (ω). Obtain the SHI value by calculating the complex viscosities at given values of the complex modulus and calculating the ratio of the two viscosities. For example, using the complex modulus values of 10 kilopascals (kPa) and 200 kPa, the values η*(10 kPa) and η*(200 kPa) are obtained with a constant complex modulus of 10 kPa and 200 kPa respectively Shear thinning index SHl (10/200) is defined as the ratio of two viscosities η*(10 kPa) and η*(200 kPa), i.e. η*(10)/η*(200).

, в которой

является величиной комплексной вязкости, η_о представляет собой вязкость при нулевом сдвиге, τη представляет собой время вязкой релаксации, a - параметр ширины, n - показатель степенной зависимости, а ω - угловая частота колебательного сдвига.Zero Shear Viscosity Method: Perform vibrational shear measurements at low stresses (10%) on polymer melts at 190°C using TAInstruments' advanced ARES-G2 rheometric expansion system with parallel plate geometry to obtain complex viscosity data ⎢η*⎪ in frequency dependence (ω). Determine values for the three parameters, zero shear viscosity, ηο, characteristic viscous relaxation time, τη, and latitude parameter, and by fitting the data obtained using the following CY Model:

, wherein

is the complex viscosity value, _ηo is the zero shear viscosity, τη is the viscous relaxation time, a is the width parameter, n is the exponent, and ω is the angular frequency of the vibrational shear.

Bimodal Catalyst System 1: Consisting essentially of or derived from bis(2-pentamethylphenylamido)ethyl)aminezirconiumdibenzyl and (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride was spray dried in a 3:1 molar ratio on CAB-O-SILTS610, a hydrophobic colloidal dioxide silicon obtained by surface treatment of hydrophilic (untreated) colloidal silicon dioxide with a dimethyldichlorosilane carrier and methylalumoxane (MAO), and loaded into a gas-phase polymerization reactor in the form of a suspension in mineral oil. The molar ratio of moles of MAO to (moles of bis(2-pentamethylphenylamido)ethyl)aminozirconiumdibenzyl + moles of (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride) was 140:1.

Comonomer 1: 1-hexene used in the 1-hexene/C2 molar ratio shown in Table 1.

Ethylene ("C2"): C2 partial pressure was maintained as described in Table 1 below.

Induced condensing agent 1 ("ICA1"): isopentane used in molar percentage concentration (mol.%) in the gas phase of the gas phase reactor relative to the total molar content of the substance in the gas phase. Shown below in Table 1.

Molecular hydrogen gas (“H ₂ ”): used in the H2/C2 molar ratio shown in Table 1.

Correction Catalyst Solution 1: consisting essentially of (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dimethyl (procatalyst) dissolved in heptane to give a solution having a concentration of procatalyst of 0.7 g per milliliter of solution (g/mL). The correction catalyst solution is further diluted in isopentane to a concentration of 0.04 wt.%.

Comparative Example 1 (CE1): monomodal polyethylene having a density of 0.937 g/cm ³ ; I ₂ 0.61 g/10 min., I ₂₁ 11.1 g/10 min. I ₂₁ /I ₂ 18.2, Mn 42050, Mw 129320, molecular weight dispersion (Mw/Mn), ĐM 3.08, was obtained as the product QHM 22F from QiluPetrochemical, People's Republic of China.

Inventive Example 1 (IE1): A bimodal PE composition IE1 was produced in a single gas phase polymerization reactor containing a continuous pilot reactor, a fluidized bed gas phase reactor with a capacity of 22 to 110 kg of resin per hour. For the experimental launch, a seed layer of granulated resin was preliminarily loaded into the reactor before launch. Dry the seed bed reactor to below 5 ppm moisture with high purity nitrogen. The constituent reaction gases were then introduced into the reactor to create a gas phase state. Simultaneously heated the reactor to the desired temperature. The reactor was charged with hydrogen gas sufficient to obtain a hydrogen to ethylene molar ratio of 0.0012 under the reaction conditions, and 1-hexene was charged to the reactor to obtain a 1-hexene to ethylene molar ratio of 0.0135 under the reaction conditions. The reactor was pressurized with ethylene (total pressure = 220 psi) and the reactor temperature was maintained at 90°C. Once the (co)polymerization conditions were reached, the initial slurry of Bimodal catalyst system 1 was introduced into the reactor. molar ratios in the range of 1.5 to 2.0 (Zr _{cat./Zr correct.} mol/mol) to fine-tune the flow index and melt index of the bimodal polyethylene composition of the present invention to the desired target values. Approximately three bed revolutions were used to reach the bimodal polyethylene production steady state, thereby giving the embodiment of the bimodal polyethylene of the present invention (product) IE1. The bimodal PE of the present invention IE1 was recovered from the reactor product discharge port and its properties were characterized. The operating components and parameters are shown in Table 1 below. Product properties of the bimodal PE of the present invention IE1 are shown in Table 2 below.

Example 2 according to the present invention (IE2): repeated the procedure of IE1, except that the temperature of the reactor was maintained at 95°C.

Table 1. Operating components/parameters for Examples of the present invention IE1 and IE2.

React Component/Parameter Conditions for (co)polymerization Reactor single, continuous, fluidized bed Initial seed coat = granular PE resin Pre-loaded into the reactor Reactor purge method Anhydrous gas N2 Ethylene ("C2") Partial pressure 1500 kPa Comonomer = 1-hexene mole ratio 1-hexene/C2 = 0.011-0.016 Molecular hydrogen gas ("H ₂ ") molar ratio H2/C2 = 0.0012 Induced condensing agent 1: isopentane 7 to 8 mol.% Working temperature 90° (IE1) or 95° (IE2) C. Layer weight Surface gas velocity (SGV, m/s) 0.60

Comparative Example (A): production of a pipe from PE CE1. Uses CE1 compound to produce SDR 11 pipe in accordance with Hydrostatic Pipe Test Methods 1 and 2 above.

Examples (A) and (B) of the present invention: preparation of bimodal PE pipes of the present invention from IE1 and IE2, respectively. Uses IE1 or IE2 compositions to produce SDR 11 pipe according to Hydrostatic Pipe Test Method 1 or 2 above.

Table 2. Properties of bimodal PE according to the present invention IE1, IE2, IE (A), IE (B), CE1 and CE (A).

Measured polymer property CE1 IE1 IE2 Density (ASTM D792-13) 0.937 g/ ^cm3 0.936 g/ ^cm3 0.936 g/ ^cm3 Melt index I ₂ (190°C, 2.16 kg, ASTMD1238-04) 0.61 g/10 min. 0.062 g/10 min. 0.063 g/10 min. Flow index I ₂₁ (190°C, 21.6 kg, ASTMD1238-04) 11.1 g/10 min. 12.1 g/10 min. 10.9 g/10 min. The ratio of flow rates (I ₂₁ /I ₂ ) 18.2 194 173 SHI (η*(10)/η*(200)) 2.76 60.5 46.4 Number average molecular weight (Mn) of the composition 42050 g/mol 21030 g/mol 23710 g/mol Weight average molecular weight (Mw) of the composition 129320 g/mol 355610 g/mol 326630 g/mol Molecular weight dispersion (Mw/Mn), ĐM compositions 3.08 16.9 13.8 Allowed bimodality (local GPC minimum) No Yes, at 5.2 LogM Yes, at 5.2 LogM The concentration of the polyethylene component LMW (wt.%) Not applicable 67.8 67.0 The concentration of the polyethylene component HMW (wt.%) Not applicable 32.2 33.0 Mn Polyethylene component LMW (g/mol) Not applicable 13980 15780 Mn Polyethylene component HMW (g/mol) Not applicable 266280 257640 Mw Polyethylene component LMW (g/mol) Not applicable 43590 46030 Mw Polyethylene component HMW (g/mol) Not applicable 1015900 901059 Mw/Mn, ĐM Polyethylene component LMW Not applicable 3.12 2.92 Mw/Mn, ĐM Polyethylene component HMW Not applicable 3.82 3.50 PENT test method (hours) 467 (failed) > 1000 > 1000 Hydrostatic Pipe Test Method 2 (90°C, 4.0 MPa) > 2000 hours > 2000 hours > 2000 hours Hydrostatic pipe test method 1 (90°C, 3.8 MPa) > 2000 hours > 2000 hours > 2000 hours

In some aspects, the bimodal PE of the present invention is characterized by any of the properties listed in Table 2 for IE1 or IE2, where the property is defined by a range having a midpoint equal to the property value listed in Table 2, and the maximum and minimum limit points are, respectively, plus or minus (±) 55%, alternatively ±25%, alternatively ±15%, alternatively ±11%, alternatively ±5%. The expected allowed bimodalities for IE1 and IE2 are illustrated by the chromatograms in FIG. 2 and 3, respectively, where the peaks for the respective LMW polyethylene components are each at approximately 4.4 LogM, the peaks for the respective HMW polyethylene components are each at approximately 5.8 LogM, and each respective local minimum is at approximately 5.2 LogM. The chromatograms in Fig. 2 and 3 each reach baseline at about 2.2 LogM and about 7.5 LogM.

The following claims are incorporated herein by reference as numbered aspects, except that "claim" and "claims" should be replaced by "aspect" or "aspects", respectively.

Claims (14)

1. A bimodal polyethylene product composition comprising a lower molecular weight (LMW) polyethylene component and a higher molecular weight (HMW) polyethylene component, wherein the LMW and HMW polyethylene components each contain monomer units derived from ethylene, and conomer units derived from (C ₃ -C ₂₀ )alpha-olefins; and wherein the bimodal low density polyethylene composition is characterized by each of the constraints (a) to (g): (a) bimodality (molecular weight distribution) as shown in a gel permeation chromatography (GPC) chromatogram of the bimodal low density polyethylene composition, where the chromatogram shows a peak representing the HMW polyethylene component, a peak representing the LMW polyethylene component, and a local minimum in the range of Log (molecular weight) ("Log(MW)")) from 3.0 to 7.0 between the peak representing the HMW polyethylene component, and a peak representing the polyethylene component LMW measured in accordance with the Bimodality Test Method of the specification; (b) a density of 0.9310 to 0.9450 grams per cubic centimeter (g/cm ³ ), measured in accordance with ASTM D792-13 Method B; (c) melt index measured in accordance with ASTM D1238-13 at 190 degrees Celsius (°C) under a load of 2.16 kg (kg) ("I ₂ " or "MI2") from 0.010 to less than 0.20 grams for 10 minutes (g / 10 minutes); (d) flow index measured in accordance with ASTM D1238-13 at 190°C under a load of 21.6 kg ("I21" or "FI21") from 8.0 to 15 g/10 min; (e) a flow rate ratio (FRR) of melt index to flow rate (“I ₂₁ /I ₂ ”) from 100.0 to 800.0; (f) more than 0 to 14 wt. % ethylene-containing chains having a molecular weight (M _W ) from more than 0 to 10,000 grams per mol (g/mol), based on the total weight of the ethylene-containing components in the bimodal PE composition; and (g) the dispersion of molecular weights (Mw/Mn), D _M is from 7 to 25, measured in accordance with the Test Method of Gel Permeation Chromatography (GPC) of the description. 2. The bimodal polyethylene composition of claim 1 wherein at least one of (a) to (f) is further defined as: (a) a local minimum Log(MW) on the GPC chromatogram ranging from 4.0 to 6 .0 Log(MW) between the peak representing the polyethylene component of the HMW and the peak representing the polyethylene component of the LMW, measured in accordance with the Bimodality Test Method; (b) density from 0.9310 to 0.9400 g/cm ³ measured in accordance with ASTM D792-13 method B; (c) melt index (I ₂ ) from 0.010 to 0.10 g/10 min, measured in accordance with ASTM D1238-13 (190° C., 2.16 kg); (d) flow index (I ₂₁ ) from 9 to 14 g/10 min; (e) the ratio of flow rates (I21/I2) from 110 to 600; and (f) from 7.0 to less than 10.0 wt. % of ethylene-containing chains having MW from more than 0 to 10000 g/mol, based on the total weight of ethylene-containing components in the bimodal PE composition. 3. Bimodal polyethylene composition according to claim 2, in which at least one of the restrictions (a)-(f) is further defined as: (a) a local minimum Log(MW) on the GPC chromatogram in the range from 5.0 to 5, 5 Log(MW) between the peak representing the polyethylene component of the HMW and the peak representing the polyethylene component of the LMW measured in accordance with the Bimodality Test Method; (b) a density of 0.935 to 0.940 g/cm ³ measured in accordance with ASTM D792-13 Method B; (c) melt index (I ₂ ) from 0.045 to 0.095 g/10 min, measured in accordance with ASTM D1238-13 (190° C., 2.16 kg); (d) flow index (I ₂₁ ) from 9 to 14, alternatively from 11 to 13 g/10 min; (e) the ratio of flow rates (I ₂₁ /I ₂ ) from 150 to 200; and (f) from 8.0 to 9.5 wt. % ethylene-containing chains having MW from more than 0 to 10000 g/mol. 4. Bimodal polyethylene composition according to any one of paragraphs. 1-3, further characterized by any of the limitations (h)-(l): (h) no measurable number of long chain branches per 1000 carbons ("LCB index") measured in accordance with the LCB Test Method of the specification; (i) a shear thinning index (SHI, η*(10)/η*(200)) value is greater than 20, measured in accordance with the Shear Loss Index Test Method of the specification; (j) the molecular weight dispersion (Mw/Mn), D _M , of the LMW polyethylene component is 2.5 to 3.5 after deconvolution of the LMW and HMW polyethylene components of the bimodal PE composition according to the Deconvolution Test Method of the specification; and (k) Mw/Mn of the HMW polyethylene component from 2.5 to 4.5, measured in accordance with the GPC Test Method, after deconvolution of the LMW and HMW polyethylene components of the bimodal PE composition in accordance with the Deconvolution Test Method; (l) each of (i), (j), and (k). 5. Bimodal polyethylene composition according to any one of paragraphs. 1-4, further characterized by at least one of the limitations of (i)-(iii): (i) PENT test result over 1000 hours measured at 90°C and 2.4 megapascals (MPa) in accordance with ASTM PENT Test Method F1473-16; and the result of the Hydrostatic test of pipes over 1000 hours, measured at 90° C. and 4.0 MPa in accordance with the Hydrostatic test of pipes 2 of the description. 6. Bimodal polyethylene composition according to any one of paragraphs. 1-5, in which comonomer units derived from (C ₃ -C ₂₀ )alpha-olefins are further described by any of the restrictions (i)-(vii): (i) comonomer units derived from (C ₃ -C ₁₀ ) alpha olefins; (ii) comonomer units derived from (C ₄ -C ₁₀ )alpha-olefins; (iii) comonomer units derived from (C ₄ -C ₈ )alpha-olefins; (iv) comonomer units derived from 1-butene; (v) comonomer units derived from 1-hexene; (vi) comonomer units derived from 1-octene; and (vii) a combination of any two from (iv) to (vi). 7. Bimodal polyethylene composition according to any one of paragraphs. 1-6, obtained by copolymerization of ethylene (monomer) and at least one (C ₃ -C ₂₀ ) alpha-olefin (comonomer) in a mixture of a bimodal catalytic system and a correction catalyst solution in the presence of gaseous molecular hydrogen (H ₂ ) and induced a condensing agent (ICA) in one, two or more polymerization reactors under (co)polymerization conditions; at the same time, before mixing, the correction catalyst solution contains a (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex and an inert liquid solvent, and the bimodal catalytic system contains an activator component, a bis(2-pentamethylphenylamido)ethyl)aminezirconium complex and a (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl) complex ) zirconium, all of them are located on a solid support; and while the conditions of (co)polymerization include the reaction temperature from 85 to 105°C; molar ratio of gaseous molecular hydrogen to ethylene (molar ratio H2/C2) from 0.0007 to 0.010; and a molar ratio of comonomer (Comer) to ethylene (molar ratio Comer/C2) of 0.0005 to 0.02. 8. The method of obtaining a bimodal polyethylene composition according to any one of paragraphs. 1-6, which includes contacting ethylene (monomer) and at least one (C ₃ -C ₂₀ )alpha-olefin (comonomer) with a mixture of a bimodal catalytic system and a correction catalyst solution in the presence of gaseous molecular hydrogen (H ₂ ) and an induced condensing agent (ICA) in one, two or more polymerization reactors under (co)polymerization conditions, resulting in a bimodal polyethylene composition; at the same time, before mixing, the correction catalyst solution contains a (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex and an inert liquid solvent, and the bimodal catalytic system contains an activator component, a complex of non-metallocene ligand - group 4 metal, and a complex of metallocene ligand - group 4 metal, all of them located on a solid carrier; and while the conditions of (co)polymerization include the reaction temperature from 85 to 105°C; molar ratio of gaseous molecular hydrogen to ethylene (molar ratio H2/C2) from 0.0007 to 0.010; and a molar ratio of comonomer (Comer) to ethylene (molar ratio Comer/C ₂ ) from 0.0005 to 0.02. 9. Bimodal polyethylene composition for the manufacture of articles according to p. 7, further characterized by any of the restrictions (i)-(vi): (i) while the bimodal catalyst system contains a complex of bis(2-pentamethylphenylamido)ethyl)aminozirconium and a complex (tetramethylcyclopentadienyl) (n-propylcyclopentadienyl)zirconium in their molar ratio from 1.0:1.0 to 5.0:1.0 and a component of methylalumoxane, all of which are sprayed onto a solid carrier; (ii) wherein the bimodal catalyst system further comprises mineral oil, and the solid support is a hydrophobic colloidal silicon dioxide; (iii) wherein the mixture is a suspension of the bimodal catalyst system in mineral oil and a correction catalyst solution, and wherein the mixture is pre-prepared and then fed to the polymerization reactor(s); (iv) wherein the correction catalyst solution is prepared by dissolving (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dimethyl in an inert liquid solvent to form a correction catalyst solution; (v) wherein the polymerization reactor(s) is a single gas phase fluidized bed reactor and the process is a gas phase polymerization; and (vi) each of (i)-(v). 10. The method for producing a bimodal polyethylene composition according to claim 8, in which the bimodal polyethylene composition is further characterized by any of the restrictions (i)-(vi): (i) wherein the bimodal catalyst system contains a complex of bis(2-pentamethylphenylamido)ethyl)aminozirconium a (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium complex in their molar ratio of 1.0:1.0 to 5.0:1.0 and a methylalumoxane component, all of which are sprayed onto a solid support; (ii) wherein the bimodal catalyst system further comprises mineral oil, and the solid support is a hydrophobic colloidal silicon dioxide; (iii) wherein the mixture is a suspension of the bimodal catalyst system in mineral oil and a correction catalyst solution, and wherein the mixture is pre-prepared and then fed to the polymerization reactor(s); (iv) wherein the correction catalyst solution is prepared by dissolving (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dimethyl in an inert liquid solvent to form a correction catalyst solution; (v) wherein the polymerization reactor(s) is a single gas phase fluidized bed reactor and the process is a gas phase polymerization; and (vi) each of (i)-(v). 11. Manufactured product containing molded from a bimodal polyethylene composition according to any one of paragraphs. 1-7 and 9. 12. A manufactured product according to claim 11, selected from pipes, films, sheets, extruded products and injection molded products. 13. A pipe consisting of a bimodal polyethylene composition according to any one of paragraphs. 1-7 and defining the internal volumetric space through which the substance can be transported. 14. The method of transporting a substance, including the movement of the substance through the internal volume of the pipe according to claim 13.

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