Polyethylene composition

Abstract

Disclosed are embodiments of polyethylene compositions and articles comprising the polyethylene compositions. The polyethylene composition may comprise a first polyethylene fraction region defined by a region in the elution profile in the temperature range of 70°C to 97°C, a first peak in the elution profile in the temperature range of 70°C to 97°C, a second polyethylene fraction region defined by a region in the elution profile in the temperature range of 97°C to 110°C, and a second peak in the temperature range of 97°C to 110°C, according to improved comonomer composition distribution (iCCD) analysis. The polyethylene composition may have a densitometric value of 0.935 g / cm. 3 ~0.955g / cm 3 and a melt index (I2) of 1.0 g / 10 min to 10.0 g / 10 min. The ratio of the first polyethylene fraction domain to the second polyethylene fraction domain may be less than 2.0.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 046,396, filed June 30, 2020, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION FIELD OF THE INVENTION Embodiments described herein relate generally to polymers, and more specifically to polyethylene compositions. [Background technology]

[0003] The use of polyolefin compositions in forming molded articles is generally known. Any conventional method can be used to produce such polyolefin compositions. Various polymerization techniques using different catalyst systems have been used to produce such polyolefin compositions suitable for forming articles. Summary of the Invention

[0004] However, despite research efforts in developing compositions suitable for forming articles, there remains a need for compositions that have a balance of stiffness and performance properties that meet customer and industry demands. Furthermore, researchers are continually seeking solutions to enable material cost reduction, for example, by downgauging (i.e., using thinner wall thicknesses) or by reducing or eliminating relatively expensive materials. For example, downgauging can be achieved by using polymer resins with higher densities, but higher densities typically result in reduced environmental stress crack resistance (ESCR). Therefore, there remains a need for compositions that have a balance of stiffness and performance properties that meet customer and industry demands.

[0005] Embodiments of the present disclosure are directed to polyethylene compositions that can exhibit desirable stiffness without compromising performance properties, such as ESCR. Thus, embodiments of the present disclosure can provide polyethylene compositions that, when utilized in the production of polymeric articles, can enable reduced material costs brought about by this balance of stiffness and ESCR properties.

[0006] According to one or more embodiments, a polyethylene composition is provided. The polyethylene composition may comprise a first polyethylene fraction region defined by a region in the elution profile in the temperature range of 70°C to 97°C, a first peak in the elution profile in the temperature range of 70°C to 97°C, a second polyethylene fraction region defined by a region in the elution profile in the temperature range of 97°C to 110°C, and a second peak in the temperature range of 97°C to 110°C, as determined by improved comonomer composition distribution (iCCD) analysis. The polyethylene composition may have a viscosity of 0.935 g / cm. 3 ~0.955g / cm 3 and a melt index (I2) of 1.0 g / 10 min to 10.0 g / 10 min. The ratio of the first polyethylene fraction domain to the second polyethylene fraction domain may be less than 2.0.

[0007] According to one or more embodiments, a polyethylene composition is provided, the polyethylene composition comprising a first polyethylene fraction in an elution profile measured by an improved comonomer composition distribution (iCCD) analysis method in a temperature range of 70°C to 97°C, the first fraction comprising a first peak and a molecular weight (Mw (iCCD、70℃~97℃) and a second polyethylene fraction in the temperature range of 97°C to 110°C in the elution profile, the second polyethylene fraction including a second peak. The polyethylene composition may have an overall molecular weight (Mw (iCCD) ), 0.935g / cm 3 ~0.955g / cm 3 and a melt index (I2) of 1.0 g / 10 min to 10.0 g / 10 min. (iCCD) The molecular weight of the first fraction (Mw(iCCD、70℃~97℃) ) may be less than 0.9.

[0008] According to one or more embodiments, an article is provided. The article may be a rotationally molded or injection molded article. The article may comprise the polyethylene composition described above.

[0009] These and other embodiments are described in more detail below in the Detailed Description of the Invention, taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0010] The following detailed description of certain embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, in which like structure is indicated with like reference numerals and in which: [Figure 1] 1 is a graph showing the elution profile of polyethylene composition 1, according to one or more embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0011] Certain embodiments of the present application will now be described. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the claimed subject matter to those skilled in the art.

[0012] The term "polymer" refers to a polymeric compound prepared by polymerizing monomers, whether of the same or different types. Thus, the general term polymer generally encompasses the term "homopolymer," which refers to a polymer prepared from only one type of monomer, and the term "copolymer," which refers to a polymer prepared from two or more different types of monomers. As used herein, the term "interpolymer" refers to a polymer prepared by polymerization of at least two different types of monomers. Thus, the general term interpolymer includes copolymers or polymers prepared from more than two different types of monomers, such as terpolymers.

[0013] "Polyethylene" or "ethylene-based polymer" shall mean a polymer containing more than 50 mole percent units derived from ethylene monomers. This includes ethylene-based homopolymers or copolymers (meaning the units are derived from two or more comonomers). Common forms of ethylene-based polymers known in the art include, but are not limited to, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (ULDPE), very low-density polyethylene (VLDPE), single-site catalyzed linear low-density polyethylene (m-LLDPE), including both linear and substantially linear low-density resins, medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0014] The term "LDPE," sometimes referred to as "high pressure ethylene polymer" or "highly branched polyethylene," is defined to mean that the polymer is partially or fully homopolymerized or copolymerized in an autoclave or tubular reactor at pressures exceeding 14,500 psi (100 MPa) using a free radical initiator such as peroxide (see, for example, U.S. Pat. No. 4,599,392, incorporated herein by reference in its entirety). LDPE resins typically have a viscosity of 0.916 g / cm. 3 ~0.940g / cm 3 The density is in the range of

[0015] The term "LLDPE" includes resins made using Ziegler-Natta catalyst systems, as well as resins made using single-site catalysts, including but not limited to bismetallocene catalysts (sometimes referred to as "m-LLDPE"), phosphinimine, and constrained geometry catalysts, and post-metallocene catalysts, including but not limited to bis(biphenylphenoxy) catalysts (also referred to as polyaryloxy ether catalysts). LLDPE includes linear, substantially linear, or heterogeneous ethylene-based copolymers or homopolymers. LLDPE contains less long chain branching than LDPE and includes substantially linear ethylene polymers as further defined in U.S. Pat. Nos. 5,272,236, 5,278,272, 5,582,923, and 5,733,155, each of which is incorporated herein by reference in its entirety; homogeneously branched linear ethylene polymer compositions such as those in U.S. Pat. No. 3,645,992, which is incorporated herein by reference in its entirety; heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Pat. No. 4,076,698, which is incorporated herein by reference in its entirety; and blends thereof (such as those disclosed in U.S. Pat. Nos. 3,914,342 and 5,854,045, which are incorporated herein by reference in their entireties). LLDPE resins may be made by gas phase, solution phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0016] The term "MDPE" means 0.930 g / cm 3 ~0.950g / cm 3MDPE refers to polyethylene with a density of 1000 MPa (1200 MPa). MDPE is typically made using chromium or Ziegler-Natta catalysts, or single-site catalysts, including but not limited to substituted mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts, and polyaryloxy ether catalysts (typically referred to as bisphenylphenoxy). Note that MDPE may be used in one or more of the outer layers.

[0017] The term "HDPE" refers to a polymer having a viscosity of 0.935 g / cm, typically prepared using a single-site catalyst, including, but not limited to, Ziegler-Natta catalysts, chromium catalysts, or substituted mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts, and polyaryloxy ether catalysts (typically referred to as bisphenylphenoxy). 3 Super~maximum 0.980g / cm 3 It refers to polyethylene having a density of

[0018] The term "ULDPE" refers to polymers with a viscosity of 0.855 g / cm, typically prepared using single-site catalysts, including, but not limited to, Ziegler-Natta catalysts, chromium catalysts, or substituted mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts, and polyaryloxy ether catalysts (typically referred to as bisphenylphenoxy). 3 ~0.912g / cm 3 ULDPE refers to polyethylene with a density of 0.855 g / cm. ULDPE includes, but is not limited to, polyethylene (ethylene-based) plastomers and polyethylene (ethylene-based) elastomers. Polyethylene (ethylene-based) elastomer plastomers generally have a density of 0.855 g / cm. 3 ~0.912g / cm 3 It has a density of

[0019] The terms "blend," "polymer blend," and the like refer to a composition of two or more polymers. Such a blend may or may not be miscible. Such a blend may or may not be phase separated. Such a blend may or may not contain one or more domain configurations as determined from transmission electron spectroscopy, light scattering, X-ray scattering, and any other method known in the art. A blend is not a laminate, although one or more layers of a laminate may contain the blend. Such a blend may be prepared as a dry blend, formed in situ (e.g., in a reactor), as a melt blend, or using other techniques known to those skilled in the art.

[0020] The terms "comprising," "including," "having," and their derivatives are not intended to exclude the presence of any additional component, step, or procedure, whether specifically disclosed or not. For the avoidance of doubt, all compositions claimed through the use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless otherwise stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any subsequent description any other component, step, or procedure, except those that are not essential to operability. The term "consisting of" excludes any component, step, or procedure not specifically delineated or listed.

[0021] Various embodiments of the polyethylene compositions are described below. Embodiments of the polyethylene compositions described herein may provide an improved balance of stiffness and ESCR properties when utilized in rotational molding applications. Furthermore, embodiments of the polyethylene compositions described herein may provide such a balance of stiffness and ESCR properties even with reduced thickness (downgauging).

[0022] As used herein, the polyethylene composition disclosed herein refers to a polyethylene terephthalate (PE)-based copolymer comprising ethylene and a C3-C 12 It may be formed from the polymerization of a comonomer such as an alkene. Contemplated comonomers include C6-C9 alkenes such as 1-octene and 1-hexene. In one or more embodiments, the comonomer is 1-octene. In one or more embodiments, the comonomer is 1-hexene.

[0023] In one or more embodiments, the polyethylene composition has a modulus of elasticity of 0.935 g / cm, as measured according to ASTM D792. 3 ~0.955g / cm 3 In embodiments, the polyethylene composition of the present disclosure may have a density of 0.935 g / cm, as measured according to ASTM D792. 3 ~0.950g / cm 3 , 0.935g / cm 3 ~0.945g / cm 3 , 0.935g / cm 3 ~0.940g / cm 3 , 0.940g / cm 3 ~0.955g / cm 3 , 0.940g / cm 3 ~0.950g / cm 3 , 0.940g / cm 3 ~0.945g / cm 3 , 0.945g / cm 3 ~0.955g / cm 3 , 0.945g / cm 3 ~0.950g / cm 3 , 0.950g / cm 3 ~0.955g / cm 3 , or a density in any combination of these ranges.

[0024] In one or more embodiments, the polyethylene composition may have a melt index (I2) of from 1.0 g / 10 minutes (g / 10 min) to 10.0 g / 10 min, when measured according to ASTM D-1238 at 190°C and 2.16 kg. In embodiments, the polyethylene composition may have a melt index (I2) of from 1.0 g / 10 min to 8.0 g / 10 min, from 1.0 g / 10 min to 6.0 g / 10 min, from 1.0 g / 10 min to 4.0 g / 10 min, from 1.0 g / 10 min to 2.0 g / 10 min, from 2.0 g / 10 min to 10.0 g / 10 min, from 2.0 g / 10 min to 8.0 g / 10 min, from 2.0 g / 10 min to 6.0 g / 10 min, or from 2.0 g / 10 min to 4. The melt index (I2) may be 0 g / 10 min, 4.0 g / 10 min to 10.0 g / 10 min, 4.0 g / 10 min to 8.0 g / 10 min, 4.0 g / 10 min to 6.0 g / 10 min, 6.0 g / 10 min to 10.0 g / 10 min, 6.0 g / 10 min to 8.0 g / 10 min, 8.0 g / 10 min to 10.0 g / 10 min, or any combination of these ranges.

[0025] In one or more embodiments, the polyethylene composition may comprise a copolymer of 5.5 to 9.5, 5.5 to 9.0, 5.5 to 8.5, 5.5 to 8.0, 5.5 to 7.5, 5.5 to 7.0, 5.5 to 6.5, 5.5 to 6.0, 6.0 to 9.5, 6.0 to 9.0, 6.0 to 8.5, 6.0 to 8.0, 6.0 to 7.5, 6.0 to 7.0, 6.0 to 6.5, 6.5 to 9.5, 6.5 to 9.0, 6.5 to 8.5, 6.5 a melt index ratio (I ) of 100 to 8.0, 6.5 to 7.5, 6.5 to 7.0, 7.0 to 9.5, 7.5 to 9.0, 7.0 to 8.5, 7.0 to 8.0, 7.0 to 7.5, 7.5 to 9.5, 7.5 to 9.0, 7.5 to 8.5, 7.5 to 8.0, 8.0 to 9.5, 8.0 to 9.0, 8.0 to 8.5, 8.5 to 9.5, 8.5 to 9.0, 9.0 to 9.5, or any combination of these ranges; 10 / I2).

[0026] According to one or more embodiments, the polyethylene composition may have a zero shear viscosity ratio of less than 2.0. In embodiments, the polyethylene composition may have a zero shear viscosity ratio of 1.0 to 2.0, 1.0 to 1.8, 1.0 to 1.6, 1.0 to 1.4, 1.0 to 1.2, 1.2 to 2.0, 1.2 to 1.8, 1.2 to 1.6, 1.2 to 1.4, 1.4 to 2.0, 1.4 to 1.8, 1.4 to 1.6, 1.6 to 2.0, 1.6 to 1.8, 1.8 to 3.0, 1.8 to 2.8, 1.8 to 2.6, 1.8 to 2.0, or any combination of ranges therein.

[0027] In embodiments, the polyethylene composition has a z-average molecular weight (Mz) of 150,000 g / mol to 400,000 g / mol, as measured by conventional GPC techniques as described herein. (GPC) According to one or more embodiments, the polyethylene composition may have a Molecular Weight (Mw) of 150,000 g / mol to 350,000 g / mol, 150,000 g / mol to 300,000 g / mol, 150,000 g / mol to 250,000 g / mol, 150,000 g / mol to 200,000 g / mol, 200,000 g / mol to 400,000 g / mol, 200,000 g / mol to 350,000 g / mol, 200,000 g / mol to 40 ... Mz of 0.01 to 300,000 g / mol, 200,000 g / mol to 250,000 g / mol, 250,000 g / mol to 400,000 g / mol, 250,000 g / mol to 350,000 g / mol, 250,000 g / mol to 300,000 g / mol, 300,000 g / mol to 400,000 g / mol, 300,000 g / mol to 350,000 g / mol, 350,000 g / mol to 400,000 g / mol, or any combination of these ranges. (GPC) may have:

[0028] In embodiments, the polyethylene composition has a number average molecular weight (Mn) in the range of 10,000 to 50,000 g / mol, as measured by conventional GPC. (GPC)For example, the number average molecular weight can be from a lower limit of 10,000, 20,000, or 25,000 g / mol to an upper limit of 35,000, 40,000, 45,000, or 50,000 g / mol.

[0029] In embodiments, the polyethylene composition has a weight average molecular weight (Mw) in the range of 60,000 to 200,000 g / mol, as measured by conventional GPC. (GPC)For example, the number average molecular weight may be 60,000 g / mol to 180,000 g / mol, 60,000 g / mol to 160,000 g / mol, 60,000 g / mol to 140,000 g / mol, 60,000 g / mol to 120,000 g / mol, 60,000 g / mol to 100,000 g / mol, 60,000 g / mol to 80,000 g / mol, 60,000 g / mol to 70,000 g / mol, 70,000 g / mol to 180,000 g / mol, as measured by conventional GPC techniques as described herein. g / mol, 70,000g / mol~160,000g / mol, 70,000g / mol~140,000g / mol, 70,000g / mol~120,000g / mol, 70,000g / mol~100,000g / mol, 70,000g / m ol~80,000g / mol, 80,000g / mol~200,000g / mol, 80,000g / mol~180,000g / mol, 80,000g / mol~160,000g / mol, 80,000g / mol~140,000g / mol, 8 0,000g / mol~120,000g / mol, 80,000g / mol~100,000g / mol, 100,000g / mol~200,000g / mol, 100,000g / mol~180,000g / mol, 100,000g / mol~1 60,000g / mol, 100,000g / mol~140,000g / mol, 100,000g / mol~120,000g / mol, 120,000g / mol~200,000g / mol, 120,000g / mol~180,000g / mol, The molecular weight may be 120,000 g / mol to 160,000 g / mol, 120,000 g / mol to 140,000 g / mol, 140,000 g / mol to 200,000 g / mol, 140,000 g / mol to 180,000 g / mol, 140,000 g / mol to 160,000 g / mol, 160,000 g / mol to 200,000 g / mol, 160,000 g / mol to 180,000 g / mol, 180,000 g / mol to 200,000 g / mol, or any combination of these ranges.

[0030] According to an embodiment, the polyethylene composition has a ratio of weight average molecular weight to number average molecular weight (Mw) in the range of 2.0 to 4.5, as measured by conventional GPC techniques. (GPC) / Mn (GPC) ), In embodiments, the polyethylene composition may have a molecular weight distribution of 2.0 to 4.0, 2.0 to 3.5, 2.0 to 3.0, 2.0 to 2.5, 2.5 to 4.5, 2.5 to 4.0, 2.5 to 3.5, 2.5 to 3.0, 3.0 to 4.5, 3.0 to 4.0, 3.0 to 3.5, 3.5 to 4.5, 3.5 to 4.0, 4.0 to 4.5, or any combination of ranges thereof. As described herein, the molecular weight distribution may be calculated according to conventional GPC techniques as described herein.

[0031] In embodiments, the polyethylene composition has a ratio of z-average molecular weight to weight average molecular weight (Mz) of 1.8 to 3.5, as measured by conventional GPC techniques as described herein. (GPC) / Mw (GPC) According to one or more embodiments, the polyethylene composition may have a ratio of z-average molecular weight to weight-average molecular weight (Mz) of 1.8 to 3.5, 1.8 to 3.0, 1.8 to 2.5, 1.8 to 2.0, 2.0 to 3.5, 2.0 to 3.0, 2.0 to 2.5, 2.5 to 3.5, 2.5 to 3.0, or 3.0 to 3.5, as measured by the light scattering GPC technique described herein. (GPC) / Mw (GPC) ).

[0032] As used herein, a polyethylene "fraction" refers to a portion of the overall composition of a multimodal polyethylene composition. Embodiments disclosed herein include at least a "first polyethylene fraction" and a "second polyethylene fraction." The various fractions contained in a polyethylene composition can be quantified by their temperature ranges in elution profiles obtained by improved comonomer composition distribution (iCCD) analysis. Unless otherwise specified, any elution profile referred to herein is an elution profile observed by iCCD. Examples of such fractions will be better understood in light of the examples provided herein. Generally, a first fraction may include a peak within the temperature range of the first fraction, and a second fraction may include a peak within the temperature range of the second fraction. The polyethylene compositions described herein may be referred to as "multimodal," meaning that the polyethylene compositions include at least two peaks in their elution profile.

[0033] In connection with the iCCD distributions described, FIG. 1 schematically illustrates a sample iCCD distribution 100. FIG. 1 generally illustrates several features of the iCCD profile of the polyethylene compositions described herein, such as the first fraction, second fraction, and half-peak width, which are discussed in detail herein. Accordingly, FIG. 1 may be used as a reference with respect to the disclosure related to the iCCD profiles provided herein. Specifically, a first fraction 102 and a second fraction 106 are illustrated. The first fraction 102 has a peak 104, and the second fraction 106 has a peak 108. Each fraction has a half-peak width 110 and 112. It should be understood that the profile in FIG. 1 is provided for informational purposes to describe specific features of the iCCD elution profile of an exemplary embodiment of the polyethylene composition described herein.

[0034] In one or more embodiments, the polyethylene composition may have a first polyethylene fraction region defined by a region in an elution profile by improved comonomer composition distribution (iCCD) analysis in the temperature range of 70° C. to 97° C. The area fraction of the first polyethylene may correspond to the total relative mass of the polymer fraction in the polyethylene composition, sometimes referred to herein as the “first mass fraction.”

[0035] In embodiments, the first polyethylene fraction may have at least one peak within the temperature range of 70°C to 97°C in an iCCD elution profile. In some embodiments, the first polyethylene fraction region may encompass the region in the elution profile below the peak in the temperature range of 70°C to 97°C in an iCCD elution profile. In further embodiments, the first polyethylene fraction may have a single peak within the temperature range of 70°C to 97°C in an iCCD elution profile. As used herein, "single peak" refers to an iCCD in which a particular fraction contains only one peak. That is, in some embodiments, the iCCD of the first polyethylene fraction contains only an upward sloping region followed by a downward sloping region to form a single peak. In one or more embodiments, the single peak of the first polyethylene fraction may be present within the temperature range of 70°C to 97°C, such as 70°C to 95°C and 70°C to 93°C.

[0036] It should be understood that the peak in the first polyethylene fraction may not be formed by a local minimum in the respective polyethylene fraction at a defined temperature boundary. That is, the peak must be a peak in terms of the entire range, rather than a peak formed by a threshold temperature for the polyethylene fraction. For example, if a polyethylene fraction has a single peak followed by a single valley (an upward slope followed by a downward slope followed by an upward slope), then only a single peak will be present in such polyethylene fraction.

[0037] According to one or more embodiments, the first polyethylene fraction region may comprise less than 60% of the total area of ​​the elution profile (e.g., less than 55% or less than 50% of the total area of ​​the elution profile). For example, the first polyethylene fraction region may comprise between 1% and 60% of the total area of ​​the elution profile, e.g., between 1% and 55%, 1% and 50%, 1% and 45%, 1% and 40%, 1% and 35%, 1% and 30%, 1% and 25%, 1% and 20%, 1% and 15%, 1% and 10%, 1% and 5%, 5% and 60%, 5% and 55%, or 5%~50%, 5%~45%, 5%~40%, 5%~35%, 5%~30%, 5%~25%, 5%~20%, 5%~15%, 5%~10%, 10%~60%, 10%~55%, 10%~50%, 10%~45%, 10%~40%, 10%~35%, 10%~30%, 10%~25%, 10%~20%, 10%~15%, 15% ~60%, 15%~55%, 15%~50%, 15%~45%, 15%~40%, 15%~35%, 15%~30%, 15%~25%, 15%~20%, 20%~60%, 20%~55%, 20%~50%, 20%~45%, 20%~40%, 20%~35%, 20%~30%, 20%~25%, 25%~60%, 25%~5 It may comprise 5%, 25% to 50%, 25% to 45%, 25% to 40%, 25% to 40%, 25% to 35%, 25% to 30%, 30% to 60%, 30% to 55%, 30% to 50%, 30% to 45%, 30% to 40%, 40% to 60%, 40% to 55%, 40% to 50%, 50% to 60%, or any combination of these ranges.

[0038] In one or more embodiments, the first polymer fraction at a temperature range of 70°C to 97°C is analyzed by iCCD analysis, as described later in this disclosure, to determine the molecular weight (Mw) of the first fraction. (iCCD、70℃~97℃) In embodiments, the molecular weight of the first fraction (Mw (iCCD、70℃~97℃)) are 80,000g / mol~180,000g / mol, 80,000g / mol~160,000g / mol, 80,000g / mol~140,000g / mol, 80,000g / mol~120,000g / mol, 80,000g / mol~100,000g / mol, 100,000g / mol~180,000g / mol, 100,000g / mol~160,000g / mol, 100,000g / mol~140,000g / mol, The weight may be 100,000 g / mol to 120,000 g / mol, 120,000 g / mol to 180,000 g / mol, 120,000 g / mol to 160,000 g / mol, 120,000 g / mol to 140,000 g / mol, 140,000 g / mol to 180,000 g / mol, 140,000 g / mol to 160,000 g / mol, 160,000 g / mol to 180,000 g / mol, or any combination of these ranges.

[0039] In one or more embodiments, the polyethylene composition may have a second polyethylene fraction region in the temperature range of 97°C to 110°C of an elution profile by improved comonomer composition distribution (iCCD) analysis. As used herein, the second polyethylene fraction region may be defined as the area in the elution profile below the second polyethylene fraction from 97°C to 110°C. The area fraction of the second polyethylene may correspond to the total relative mass of the polymer fraction in the polyethylene composition, referred to herein as the "second mass fraction."

[0040] In one or more embodiments, the second polyethylene fraction may have a single peak within the temperature range of 97°C to 110°C in an iCCD elution profile. It should be understood that the peak in the second polyethylene fraction may not be formed by a local minimum in the respective polyethylene fraction at a defined temperature boundary. That is, the peak must be a peak in terms of the entire range, rather than a peak formed by a threshold temperature for the polyethylene fraction. For example, if a polyethylene fraction has a single peak followed by a single valley (an upward slope followed by a downward slope followed by an upward slope), then only a single peak will be present in that polyethylene fraction. A temperature range of 97°C to 110°C for the second polyethylene fraction may be desirable because the low molecular weight, high density components at 97°C to 110°C allow the polyethylene to achieve a higher overall density while maintaining a lower density fraction.

[0041] According to one or more embodiments, the second polyethylene fraction region may comprise 30% or more of the total area of ​​the elution profile (e.g., 40% or more, 50% or more, 60% or more, or 70% or more of the total area of ​​the elution profile). For example, the second polyethylene fraction region may comprise 30% to 80%, 30% to 70%, 30% to 60%, 30% to 50%, 30% to 40%, 40% to 80%, 40% to 70%, 40% to 60%, 40% to 50%, 50% to 80%, 50% to 70%, 50% to 60%, 60% to 80%, 60% to 70%, or 70% to 80% of the total area of ​​the elution profile.

[0042] According to some embodiments, the molecular weight of the overall polyethylene composition (Mw (iCCD) ) the molecular weight (Mw (iCCD、70℃~97℃)) can be less than 0.90 (e.g., less than 0.88, less than 0.86, less than 0.84, less than 0.82, less than 0.80). For example, the ratio of the molecular weight of the entire polyethylene composition to the molecular weight of the first fraction can be 0.80 to 0.90, 0.80 to 0.88, 0.80 to 0.86, 0.80 to 0.84, 0.80 to 0.82, 0.82 to 0.90, 0.82 to 0.88, 0.82 to 0.86, 0.82 to 0.84, 0.84 to 0.90, 0.84 to 0.88, 0.84 to 0.86, 0.86 to 0.90, 0.86 to 0.88, or 0.88 to 0.90. Without being bound by theory, it is believed that having a ratio of less than 0.9 means that the low-density component (the first fraction between 70°C and 97°C) has a higher molecular weight than the average molecular weight of the entire polyethylene composition. Therefore, the low-density component with a higher molecular weight can promote bond chain formation in the polymer matrix of the polyethylene composition, which can be beneficial for ESCR and toughness properties.

[0043] According to some embodiments, the ratio of the first mass fraction to the second mass fraction can be less than 2.0 (eg, less than 1.8, less than 1.6, less than 1.4, less than 1.2, or less than 1.0). For example, the ratio of the first mass fraction to the second mass fraction may be 0.6 to 2.0, 0.6 to 1.8, 0.6 to 1.6, 0.6 to 1.4, 0.6 to 1.2, 0.6 to 1.0, 0.6 to 0.8, 0.8 to 2.0, 0.8 to 1.8, 0.8 to 1.6, 0.8 to 1.4, 0.8 to 1.2, 0.8 to 1.0, 1.0 to 2.0, 1.0 to 1.8, 1.0 to 1.6, 1.0 to 1.4, 1.0 to 1.2, 1.2 to 2.0, 1.2 to 1.8, 1.2 to 1.6, 1.2 to 1.4, 1.4 to 2.0, 1.4 to 1.8, 1.4 to 1.6, 1.6 to 2.0, 1.6 to 1.8, or 1.8 to 2.0. Without being bound by theory, having a lower value for this ratio means that there is less of the low density, high molecular weight component (the first fraction between 70°C and 97°C), but the overall polyethylene composition may still exhibit improved properties such as ESCR and toughness. Having more of the high density, low molecular weight component (the second fraction between 97°C and 110°C) may allow the polyethylene composition to have sufficient stiffness while improving the flow of the product. As described later in this disclosure, improved flow can be beneficial to various article fabrication methods and may enable more complex article designs.

[0044] Embodiments of the polyethylene compositions described herein may be further characterized by a Comonomer Distribution Breadth Index 50 (CDBI50) of 50% or less (e.g., 40% or less, 30% or less, and 40% or less). As used herein, CDBI50 is defined as the weight percent of polymer molecules having a comonomer content within 50 percent of the median total molar comonomer content. It represents a comparison of the comonomer distribution in a polymer to that predicted by a Bernoulli distribution. In further embodiments, the polyethylene compositions may have a CDBI50 of 10% to 50%, 10% to 40%, 10% to 30%, 10% to 20%, 20% to 50%, 20% to 40%, 20% to 30%, 30% to 50%, 30% to 40%, or 40% to 50%. Without being bound by theory, having a CDBI50 of less than 50% represents a broader comonomer distribution and reflects a broad density split that cannot be achieved with some conventional polyethylene compositions. A broad density split may promote high levels of chain formation from the low density, high molecular weight fraction, which contributes to overall ESCR and toughness properties. Furthermore, a broad density split may contribute to necessary stiffness properties that may enable downgauging of the product.

[0045] Polymerization of polyethylene compositions Any conventional polymerization process can be used to produce the polyethylene composition in the presence of the catalyst system of the present disclosure, including, but not limited to, solution polymerization processes, gas phase polymerization processes, slurry phase polymerization processes, and combinations thereof, using one or more conventional reactors, such as loop reactors, isothermal reactors, adiabatic reactors, fluidized bed gas phase reactors, stirred tank reactors, batch reactors, etc., in parallel, in series, or in any combination.

[0046] The polyethylene composition may be produced, for example, via a solution phase polymerization process using one or more loop reactors, adiabatic reactors, and combinations thereof. Generally, the solution phase polymerization process may be carried out in one or more well-mixed reactors, such as one or more loop reactors and / or one or more adiabatic reactors, at a temperature ranging from 115 to 250°C, e.g., from 135°C to 200°C, and a pressure ranging from 300 psig to 1000 psig, e.g., from 450 psig to 750 psig.

[0047] In one embodiment, the polyethylene composition may be produced in two loop reactors in a series configuration, with the first reactor temperature ranging from 115 to 200°C, e.g., 135 to 165°C, and the second reactor temperature ranging from 150 to 210°C, e.g., 185 to 200°C. In another embodiment, the polyethylene composition may be produced in a single reactor, with the reactor temperature ranging from 115 to 200°C, e.g., 130 to 190°C. The residence time in a solution-phase polymerization process is typically in the range of 2 to 40 minutes, e.g., 5 to 20 minutes. Ethylene, solvent, one or more catalyst systems, optionally one or more cocatalysts, and optionally one or more comonomers are continuously fed into one or more reactors. Exemplary solvents include, but are not limited to, isoparaffins. For example, such solvents are commercially available from ExxonMobil Chemical under the name ISOPAR E. The resulting mixture of polyethylene composition and solvent is then removed from the reactor or reactors, and the polyethylene composition is isolated. The solvent is typically recovered through a solvent recovery unit, i.e., a heat exchanger and separator vessel, and then recycled back into the polymerization system.

[0048] In one embodiment, the polyethylene composition may be produced via a solution polymerization process in a dual reactor system, e.g., a dual loop reactor system, in which ethylene and optionally one or more α-olefins are polymerized in one reactor in the presence of one or more catalyst systems to produce a first ethylene-based polymer, and ethylene and optionally one or more α-olefins are polymerized in a second reactor in the presence of one or more catalyst systems to produce a second ethylene-based polymer. In addition, one or more co-catalysts may be present. In another embodiment, the polyethylene composition may be produced by a solution polymerization process in a single reactor system, e.g., a single loop reactor system, in which ethylene and optionally one or more α-olefins are polymerized in the presence of one or more catalyst systems. In addition, one or more co-catalysts may be present.

[0049] catalyst system Described herein are specific embodiments of catalyst systems that can be used in one or more embodiments to produce the polyethylene compositions described herein. It is understood that the catalyst systems of the present disclosure may be embodied in different forms and should not be construed as limited to the specific embodiments described in this disclosure. Rather, the embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art.

[0050] The term "independently selected" refers to 1 , R 2 , R 3 , R 4 , and R 5 and the R groups may be the same or different (e.g., R 1 , R 2 , R 3 , R 4 , and R 5 are all substituted alkyl, or R 1 and R 2 is a substituted alkyl, and R 3The terms "a" and "an" are used herein to indicate that an R group is an alkyl group, and the R group may be an aryl group, etc. The use of the singular includes the use of the plural and vice versa (e.g., hexane solvent includes a plurality of hexanes). A named R group will generally have a structure recognized in the art as corresponding to the R group with that name. These definitions are intended to supplement and illustrate, not preclude, definitions known to those of skill in the art.

[0051] The term "procatalyst" refers to a compound that has catalytic activity when combined with an activator. The term "activator" refers to a compound that chemically reacts with a procatalyst to convert the procatalyst into a catalytically active catalyst. As used herein, the terms "cocatalyst" and "activator" are interchangeable terms.

[0052] When used to describe a chemical group containing a particular carbon atom, "(C x ~C y A bracketed expression having the form "(C1-C )" means that the unsubstituted form of the chemical group has from x carbon atoms to y carbon atoms, inclusive of x and y. For example, (C1-C 40 ) Alkyl is an alkyl group having 1 to 40 carbon atoms in its unsubstituted form. In some embodiments and general structures, certain chemical groups are S The parenthesized "(C x -C y )" for the chemical group R S Substituted versions may be formed by adding any group R S may contain more than y carbon atoms depending on the identity of S exactly one group R is phenyl (-C6H5) S (C1~C 40 A "(C ) alkyl" can contain from 7 to 46 carbon atoms. Therefore, the parenthesized "(C ) alkyl" is generally used. x ~C y )" is a substituent R SWhen substituted by, the minimum and maximum total number of carbon atoms in the chemical group are the substituents R containing all carbon atoms in both x and y. S It is determined by adding the total number of carbon atoms from

[0053] The term "substituted" means that at least one hydrogen atom (-H) bonded to a carbon or heteroatom or functional group of the corresponding unsubstituted compound is replaced by a substituent (e.g., R S The term "hypersubstituted" means that all hydrogen atoms (H) bonded to carbon atoms or heteroatoms of the corresponding unsubstituted compound or functional group are replaced by a substituent (e.g., R S The term "polysubstituted" means that at least two, but fewer than all, hydrogen atoms bonded to carbon atoms or heteroatoms of the corresponding unsubstituted compound or functional group are replaced by substituents.

[0054] The term "-H" means a hydrogen or hydrogen radical that is covalently bonded to another atom. "Hydrogen" and "-H" are interchangeable and mean the same thing unless otherwise specified.

[0055] "(C1~C 40 The term "(C1-C)hydrocarbyl" means a hydrocarbon radical of 1 to 40 carbon atoms. 40 The term "hydrocarbylene" means a hydrocarbon diradical of 1 to 40 carbon atoms, wherein each hydrocarbon radical and each hydrocarbon diradical is aromatic or non-aromatic, saturated or unsaturated, straight or branched chain, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic, including bicyclic, 3 or more carbon atoms) or acyclic, unsubstituted or substituted with one or more R S has been replaced by

[0056] In the present disclosure, (C1 to C 40 ) Hydrocarbyl is unsubstituted or substituted (C1-C 40 ) Alkyl, (C3-C 40 ) cycloalkyl, (C3-C20 )Cycloalkyl-(C1-C 20 ) alkylene, (C6-C 40 ) aryl, or (C6-C 20 )Aryl-(C1-C 20 In some embodiments, the above (C1-C) alkylene may be 40 Each of the hydrocarbyl groups has up to 20 carbon atoms (i.e., (C1-C 20 ) hydrocarbyl), in embodiments having up to 12 carbon atoms.

[0057] "(C1~C 40 ) alkyl" and "(C1-C 18 The term "alkyl" refers to an alkyl group of 1 to 40 carbon atoms or 1 to 18 carbon atoms, unsubstituted or substituted with one or more R S means a saturated straight-chain or branched hydrocarbon radical substituted by an unsubstituted (C1-C 40 Examples of alkyl are unsubstituted (C1-C 20 ) Alkyl, unsubstituted (C1-C 10 ) alkyl, unsubstituted (C1-C5) alkyl, methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methylpropyl, 1,1-dimethylethyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-nonyl, and 1-decyl. 40 Examples of substituted (C1-C 20 ) Alkyl, substituted (C1-C 10 ) alkyl, trifluoromethyl, and [C 45 ] alkyl. 45 The term "(C1-C5) alkyl" (with brackets) means that there are up to 45 carbon atoms in the radical, including the substituents, e.g., one R S replaced by (C 27 ~C 40 Each (C1-C5)alkyl can be methyl, trifluoromethyl, ethyl, 1-propyl, 1-methylethyl, or 1,1-dimethylethyl.

[0058] "(C6~C 40 The term "aryl" refers to an unsubstituted or (one or more R)aryl having 6 to 40 carbon atoms, of which at least 6 to 14 carbon atoms are aromatic ring carbon atoms. S means a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon radical substituted (by C6-C), wherein the monocyclic, bicyclic, or tricyclic radical contains one, two, or three rings, respectively, wherein the monocyclic ring is aromatic and the two or three rings are independently fused or unfused, and at least one of the two or three rings is aromatic. 40 Examples of alkyl are unsubstituted (C-C 20 ) Unsubstituted alkyl (C6-C 18 ) alkyl, 2-(C1-C5) alkylphenyl, 2,4-bis(C1-C5) alkylphenyl, phenyl, fluorenyl, tetrahydrofluorenyl, indacenyl, hexahydroindacenyl, indenyl, dihydroindenyl, naphthyl, tetrahydronaphthyl, and phenanthrene. 40 Examples of substituted (C1-C 20 ) Alkyl, substituted (C6-C 18 )aryl, 2,4-bis[(C 20 ) alkyl]-phenyl, polyfluorophenyl, pentafluorophenyl, and fluoren-9-on-1-yl.

[0059] "(C3~C 40 The term "cycloalkyl" refers to a group that is unsubstituted or has one or more R S means a saturated cyclic hydrocarbon radical of 3 to 40 carbon atoms, substituted with other cycloalkyl groups, such as (C x ~C y )cycloalkyl) has x to y carbon atoms and is unsubstituted or has one or more R S Unsubstituted (C3-C 40 Examples of cycloalkyl are unsubstituted (C-C 20 ) Cycloalkyl, unsubstituted (C3-C 10) cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. 40 Examples of cycloalkyl are substituted (C3-C 20 ) Cycloalkyl, substituted (C3-C 10 ) cycloalkyl, cyclopentanon-2-yl, and 1-fluorocyclohexyl.

[0060] (C1~C 40 Examples of hydrocarbylene include unsubstituted or substituted (C6-C 40 )Arylene, (C3-C 40 ) cycloalkylene, and (C1-C 40 ) alkylene (e.g. (C1-C 20 ) alkylene). In some embodiments, the diradicals are on the same carbon atom (e.g., —CH2—), or on adjacent carbon atoms (i.e., 1,2-diradicals), or separated by one, two, or more than two intervening carbon atoms (e.g., 1,3-diradicals, 1,4-diradicals, etc., respectively). Some diradicals include α,ω-diradicals. α,ω-diradicals are diradicals with the greatest carbon backbone spacing between the radical carbons. (C2-C 20 Some examples of alkylene α,ω-diradicals include ethane-1,2-diyl (i.e., -CHCH-), propane-1,3-diyl (i.e., -CHCHCH-), and 2-methylpropane-1,3-diyl (i.e., -CHCH(CH)CH-). (C6-C 50 Some examples of arylene α,ω-diradicals include phenyl-1,4-diyl, naphthalene-2,6-diyl, or naphthalene-3,7-diyl.

[0061] "(C1~C 40 The term "alkylene" refers to a group that is unsubstituted or has one or more R Smeans a saturated straight or branched chain diradical (i.e., the radical is not on a ring atom) of 1 to 40 carbon atoms, substituted with 50 Examples of alkylene are unsubstituted -CH2CH2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -(CH2)7-, -(CH2)8-, -CH2C * HCH3 and -(CH2)4C * (H) Unsubstituted (C1-C) containing CH3 20 ) alkylene, wherein "C * " represents a carbon atom from which a hydrogen atom is removed to form a secondary or tertiary alkyl radical. 50 Examples of alkylene are substituted (C1-C 20 ) alkylene, -CF2-, -C(O)-, and -(CH2) 14 C(CH3)2(CH2)5- (i.e., 6,6-dimethyl-substituted normal-1,20-eicosylene). As mentioned above, the two R S together (C1~C 18 ) alkylene, so that substituted (C1-C 50 Examples of )alkylene also include 1,2-bis(methylene)cyclopentane, 1,2-bis(methylene)cyclohexane, 2,3-bis(methylene)-7,7-dimethyl-bicyclo[2.2.1]heptane, and 2,3-bis(methylene)bicyclo[2.2.2]octane.

[0062] "(C3~C 40 The term "cycloalkylene" refers to a group that is unsubstituted or has one or more R S means a cyclic diradical (i.e., the radicals are on ring atoms) of 3 to 40 carbon atoms substituted by

[0063] The term "heteroatom" refers to an atom other than hydrogen or carbon. Examples of heteroatoms include O, S, S(O), S(O), Si(R C )2, P(R P ), N(R N ), -N=C(R C)2, -Ge(R C )2-, or -Si(R C )-, wherein each R C , each R N , and each R P is unsubstituted (C1 to C 18 ) hydrocarbyl or -H. The term "heterohydrocarbon" refers to a molecule or molecular skeleton in which one or more carbon atoms are replaced with a heteroatom. 40 The term "(C1-C)heterohydrocarbyl" means a heterohydrocarbon radical of 1 to 40 carbon atoms. 40 The term "heterohydrocarbylene" means a heterohydrocarbon diradical of 1 to 40 carbon atoms, each heterohydrocarbon having one or more heteroatoms. The heterohydrocarbyl radical can be present on a carbon atom or a heteroatom, and the heterohydrocarbyl diradical can be present on (1) one or two carbon atoms, (2) one or two heteroatoms, or (3) one carbon atom and one heteroatom. Each (C1 to C 50 ) heterohydrocarbyl and (C1-C 50 ) heterohydrocarbylene is unsubstituted or substituted (one or more R S The aromatic ring may be aromatic or non-aromatic, saturated or unsaturated, straight or branched chain, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic) or acyclic.

[0064] (C1~C 40 ) Heterohydrocarbyl is unsubstituted or substituted (C1-C 40 ) heteroalkyl, (C1-C 40 ) hydrocarbyl-O-, (C1-C 40 ) hydrocarbyl-S-, (C1-C 40 ) hydrocarbyl-S(O)-, (C1-C 40 ) hydrocarbyl-S(O)2-, (C1-C 40 ) Hydrocarbyl-Si(R C )2-, (C1~C 40 )hydrocarbyl-N(R N )-, (C1~C 40 ) hydrocarbyl-P(R P)-, (C2~C 40 ) heterocycloalkyl, (C2-C 19 )Heterocycloalkyl-(C1-C 20 ) alkylene, (C3-C 20 )Cycloalkyl-(C1-C 19 ) heteroalkylene, (C2-C 19 )Heterocycloalkyl-(C1-C 20 ) heteroalkylene, (C1-C 40 ) heteroaryl, (C1-C 19 )Heteroaryl-(C1-C 20 ) alkylene, (C6-C 20 )Aryl-(C1-C 19 ) heteroalkylene, or (C1-C 19 )Heteroaryl-(C1-C 20 ) heteroalkylene.

[0065] "(C4~C 40 The term "heteroaryl" refers to an unsubstituted or substituted (one or more R) heteroaryl group of a total of 4 to 40 carbon atoms and 1 to 10 heteroatoms. S

[0033] The term "heteroaromatic hydrocarbon radical" refers to a monocyclic, bicyclic, or tricyclic heteroaromatic hydrocarbon radical (according to the formula (C)), wherein the monocyclic, bicyclic, or tricyclic radical contains one, two, or three rings, respectively, which are independently fused or unfused, and at least one of the two or three rings is heteroaromatic. Other heteroaryl groups (e.g., generally (C) x ~C y ) heteroaryl, such as (C4-C 12 ) heteroaryl) similarly has x to y carbon atoms (e.g., 4 to 12 carbon atoms) and is unsubstituted or has one or more R SThe monocyclic heteroaromatic hydrocarbon radical is defined as being substituted by a 5-membered or 6-membered ring. The 5-membered ring has 5 minus h carbon atoms, where h is the number of heteroatoms and may be 1, 2, or 3, and each heteroatom may be O, S, N, or P. Examples of 5-membered heteroaromatic hydrocarbon radicals include pyrrol-1-yl, pyrrol-2-yl, furan-3-yl, thiophen-2-yl, pyrazol-1-yl, isoxazol-2-yl, isothiazol-5-yl, imidazol-2-yl, oxazol-4-yl, thiazol-2-yl, 1,2,4-triazol-1-yl, 1,3,4-oxadiazol-2-yl, 1,3,4-thiadiazol-2-yl, tetrazol-1-yl, tetrazol-2-yl, and tetrazol-5-yl. A 6-membered ring has 6 minus h carbon atoms, where h is the number of heteroatoms, which may be 1 or 2, and the heteroatoms may be N or P. Examples of 6-membered heteroaromatic hydrocarbon radicals include pyridin-2-yl, pyrimidin-2-yl, and pyrazin-2-yl. Bicyclic heteroaromatic hydrocarbon radicals may be fused 5,6- or 6,6-ring systems. Examples of fused 5,6-ring bicyclic heteroaromatic hydrocarbon radicals are indol-1-yl and benzimidazol-1-yl. Examples of fused 6,6-ring bicyclic heteroaromatic hydrocarbon radicals are quinolin-2-yl and isoquinolin-1-yl. Tricyclic heteroaromatic hydrocarbon radicals may be fused 5,6,5-, 5,6,6-, 6,5,6-, or 6,6,6-ring systems. An example of a fused 5,6,5-ring system is 1,7-dihydropyrrolo[3,2-f]indol-1-yl. An example of a fused 5,6,6-ring system is 1H-benzo[f]indol-1-yl. An example of a fused 6,5,6-ring system is 9H-carbazol-9-yl. An example of a fused 6,5,6-ring system is 9H-carbazol-9-yl. An example of a fused 6,6,6-ring system is acridine-9-yl.

[0066] The heteroalkyl group may be any of (C1-C 50) carbon atoms and one or more heteroatoms. Similarly, heteroalkylene may be a saturated straight or branched chain diradical containing 1 to 50 carbon atoms and one or more heteroatoms. Heteroatoms as defined above include Si(R C )3, Ge(R C )3, Si(R C )2, Ge(R C )2, P(R P )2, P(R P ), N(R N )2, N(R N ), N, O, OR C , S, S.R. C , S(O), and S(O)2, each of the heteroalkyl and heteroalkylene groups being unsubstituted or containing one or more R S is replaced by

[0067] Unsubstituted (C2~C 40 Examples of heterocycloalkyl include unsubstituted (C-C 20 ) Heterocycloalkyl, unsubstituted (C2-C 10 ) heterocycloalkyl, aziridin-l-yl, oxetan-2-yl, tetrahydrofuran-3-yl, pyrrolidin-l-yl, tetrahydrothiophene-S,S-dioxid-2-yl, morpholin-4-yl, 1,4-dioxan-2-yl, hexahydroazepin-4-yl, 3-oxa-cyclooctyl, 5-thio-cyclononyl, and 2-aza-cyclodecyl.

[0068] The term "halogen atom" or "halogen" refers to a radical of a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I). The term "halide" refers to a halogen atom: fluoride (F - ), chloride (Cl - ), bromide (Br - ), or iodide (I - ) means the anionic form of

[0069] The term "saturated" means lacking carbon-carbon double bonds, carbon-carbon triple bonds, and (in heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds. A saturated chemical group is one or more substituents R S When substituted by, one or more double and / or triple bonds may optionally be substituted by a substituent R S The term "unsaturated" refers to the presence of one or more carbon-carbon double bonds, carbon-carbon triple bonds, and (in heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds, provided that the substituents R, if present, are not present in the group. S It is meant to exclude any double bonds that may be present in, or, if present, in, a (hetero)aromatic ring.

[0070] According to some embodiments, a catalyst system for producing a polyethylene composition comprises a metal-ligand complex according to formula (I):

[0071] [ka]

[0072] In formula (I), M is a metal selected from titanium, zirconium, or hafnium, the metal being in a +2, +3, or +4 formal oxidation state; n is 0, 1, or 2; when n is 1, X is a monodentate or bidentate ligand; when n is 2, each X is a monodentate ligand and is the same or different; the metal-ligand complex is overall charge neutral; and each Z is independently —O—, —S—, —N(R N )-, or -P(R P )-, and L is selected from (C1 to C 40 ) hydrocarbylene or (C1-C 40 ) heterohydrocarbylene, (C1-C 40 ) Hydrocarbylene has a moiety containing a linker skeleton of 1 to 10 carbon atoms connecting the two Z groups in formula (I) (to which L is attached), or (C1 to C 40) Heterohydrocarbylene has a moiety containing a linker skeleton of 1 atom to 10 atoms connecting the two Z groups in formula (I), and (C1-C 40 Each of the 1 to 10 atoms of the 1 to 10 atom linker backbone of the heterohydrocarbylene is independently a carbon atom or a heteroatom, and each heteroatom is independently O, S, S(O), S(O), Si(R C )2, Ge(R C )2, P(R C ), or N(R C ) and independently, each R C is (C1~C 30 ) hydrocarbyl or (C1-C 30 ) heterohydrocarbyl, and R 1 and R 8 are independently -H, (C1 to C 40 ) hydrocarbyl, (C1-C 40 ) heterohydrocarbyl, -Si(R C )3, -Ge(R C )3, -P(R P )2, -N(R N )2, -OR C , -SR C , -NO2, -CN, -CF3, R C S(O)-, R C S(O)2-, (R C )2C=N-, R C C(O)O-, R C OC(O)-, R C C(O)N(R N )-, (R N )2NC(O)-, halogen, and a radical having formula (II), formula (III), or formula (IV):

[0073] [ka]

[0074] In formulas (II), (III), and (IV), R 31~35 , R 41~48 , or R 51~59 Each of (C1 to C 40) hydrocarbyl, (C1-C 40 ) heterohydrocarbyl, -Si(R C )3, -Ge(R C )3, -P(R P )2, -N(R N )2, -N=CHR C , -OR C , -SR C , -NO2, -CN, -CF3, R C S(O)-, R C S(O)2-, (R C )2C=N-, R C C(O)O-, R C OC(O)-, R C C(O)N(R N )-, (R N )2NC(O)-, halogen, or -H, with the proviso that R 1 or R 8 is a radical having formula (II), formula (III), or formula (IV).

[0075] In formula (I), R 2~4 , R 5~7 , and R 9~16 Each of (C1 to C 40 ) hydrocarbyl, (C1-C 40 ) heterohydrocarbyl, -Si(R C )3, -Ge(R C )3, -P(R P )2, -N(R N )2, -N=CHR C , -OR C , -SR C , -NO2, -CN, -CF3, R C S(O)-, R C S(O)2-, (R C )2C=N-, R C C(O)O-, R C OC(O)-, R C C(O)N(R N )-, (R C )2NC(O)-, halogen, and -H.

[0076] In some embodiments, the polyethylene composition is formed using a first catalyst according to formula (I) in a first reactor and a different catalyst according to formula (I) in a second reactor.

[0077] In one exemplary embodiment using a dual loop reactor, the procatalyst used in the first loop is zirconium, [[2,2''-[[bis[1-methylethyl]germylene]bis(methyleneoxy-κO)]bis[3'',5,5''-tris(1,1-dimethylethyl)-5'-octyl[1,1':3',1''-terphenyl]-2'-olato-κO]](2-)]dimethyl-, which has the chemical formula C 86 H 128 F2GeO4Zr and has the following structure (V):

[0078] [ka]

[0079] In such embodiments, the procatalyst used in the second loop is zirconium, [[2,2'''-[1,3-propanediylbis(oxy-κO)]bis[3-[2,7-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]]-5'-(dimethyloctylsilyl)-3'-methyl-5-(1,1,3,3-tetramethylbutyl)[1,1]-biphenyl]-2-olato-κO]](2-)]dimethyl, and has the chemical formula C 107 H 154 N2O4Si2Zr and having the following structure (VI):

[0080] [ka]

[0081] cocatalyst component Catalyst systems containing the metal-ligand complexes of formula (I) can be catalytically activated by any technique known in the art for activating metal-based catalysts for olefin polymerization reactions. For example, systems containing the metal-ligand complexes of formula (I) can be catalytically activated by contacting the complex with or combining the complex with an activating cocatalyst. Activating cocatalysts suitable for use herein include alkylaluminums, polymeric or oligomeric alumoxanes (also known as aluminoxanes), neutral Lewis acids, and non-polymeric, non-coordinating, ion-forming compounds (including the use of such compounds under oxidizing conditions). A suitable activation technique is bulk electrolysis. Combinations of one or more of the foregoing activating cocatalysts and techniques are also contemplated. The term "alkylaluminum" refers to monoalkylaluminum dihydrides or dihalides, dialkylaluminum hydrides or halides, or trialkylaluminums. Examples of polymeric or oligomeric alumoxanes include methylalumoxane, triisobutylaluminum modified methylalumoxane, and isobutylalumoxane.

[0082] The Lewis acid activator (cocatalyst) may be, as described herein, a compound having one to three (C1-C 20 In one embodiment, the Group 13 metal compound includes a tri((C1-C) hydrocarbyl substituent. 20 )hydrocarbyl)substituted aluminum or tri((C1-C 20 In an embodiment, the Group 13 metal compound is a tri(hydrocarbyl)-substituted aluminum, tri((C1-C 20 )hydrocarbyl)-boron compounds, tri((C1-C 10 ) alkyl) aluminum, tri((C6-C 18)aryl)boron compounds and their halogenated (including perhalogenated) derivatives. In further embodiments, the Group 13 metal compound is tris(fluoro-substituted phenyl)borane, tris(pentafluorophenyl)borane. In some embodiments, the activating cocatalyst is tris((C1-C 20 ) hydrocarbyl borate (e.g., trityl tetrafluoroborate) or tri((C 20 )hydrocarbyl)ammonium tetra((C1-C 20 )hydrocarbyl)borane (e.g., bis(octadecyl)methylammonium tetrakis(pentafluorophenyl)borane). As used herein, the term "ammonium" refers to a ((C1-C 20 ) Hydrocarbyl) 4N + , ((C1~C 20 )hydrocarbyl)3N(H) + , ((C1~C 20 )hydrocarbyl)2N(H)2 + , (C1~C 20 ) Hydrocarbyl N(H)3 + , or N(H)4 + In the formula, each of (C1 to C 20 When two or more hydrocarbyls are present, they may be the same or different.

[0083] As a combination of neutral Lewis acid activators (cocatalysts), tri((C1-C4) alkyl)aluminum and tri((C6-C 18(aryl)boron compounds, particularly tris(pentafluorophenyl)borane. Embodiments include mixtures containing such neutral Lewis acid mixtures in combination with polymeric or oligomeric alumoxanes, and combinations of a single neutral Lewis acid, particularly tris(pentafluorophenyl)borane, with polymeric or oligomeric alumoxanes. The molar ratio of (metal-ligand complex):(tris(pentafluorophenyl)borane):(alumoxane) [e.g., Group 4 metal-ligand complex):(tris(pentafluorophenyl)borane):(alumoxane)] is 1:1:1 to 1:10:30, and in embodiments, 1:1:1.5 to 1:5:10.

[0084] Catalyst systems comprising the metal-ligand complexes of formula (I) may be activated to form active catalyst compositions by combination with one or more cocatalysts, such as cation-forming cocatalysts, strong Lewis acids, or combinations thereof. Suitable activating cocatalysts include polymeric or oligomeric aluminoxanes, particularly methylaluminoxane, as well as inert, compatible, non-coordinating, ion-forming compounds. Examples of suitable cocatalysts include modified methyl aluminoxane (MMAO), bis(hydrogenated tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate (1 - ) amines, and combinations thereof.

[0085] In some embodiments, one or more of the aforementioned activating cocatalysts are used in combination with one another. Particularly preferred combinations are mixtures of tri((C1-C4)hydrocarbyl)aluminum, tri((C1-C4)hydrocarbyl)borane, or ammonium borate with an oligomeric or polymeric alumoxane compound. The ratio of the total moles of one or more metal-ligand complexes of Formula (I) to the total moles of one or more activating cocatalysts is from 1:10,000 to 100:1. In some embodiments, this ratio is at least 1:5000, in some embodiments at least 1:1000, and up to 10:1, and in some embodiments, up to 1:1. When alumoxane is used alone as the activating cocatalyst, the number of moles of alumoxane used is preferably at least 100 times the number of moles of the metal-ligand complex of Formula (I). When tris(pentafluorophenyl)borane is used alone as the activating cocatalyst, in some embodiments, the number of moles of tris(pentafluorophenyl)borane used relative to the total number of moles of one or more metal-ligand complexes of Formula (I) is from 0.5:1 to 10:1, from 1:1 to 6:1, or from 1:1 to 5:1. The remaining activating cocatalyst is generally used in a molar amount approximately equal to the total molar amount of one or more metal-ligand complexes of Formula (I).

[0086] Goods Embodiments of the present disclosure also relate to articles, such as rotomolded and injection molded articles, formed from the polyethylene films of the present disclosure. Such articles may be formed from any of the polyethylene compositions of the present disclosure described herein.

[0087] Rotational molding, commonly referred to as "rotomolding" or "rotocasting," is widely used to form hollow articles. Rotational molding articles, such as storage tanks, furniture, toys, canoes and kayaks, and slides, can be used in a variety of applications and industries. In particular, rotational molding allows materials to be molded into complex shapes and completely fill corners and narrow compartments. Generally, rotational molding involves depositing a polymer resin inside a mold, heating the filled mold to melt the polymer resin, spinning the mold to deposit the molten resin on the inside of the mold, cooling the mold, and removing the molded article from the mold. One-piece hollow articles can be made by rotational molding. Examples of rotational molding articles include, but are not limited to, toys, furniture, containers, such as tanks and water bottles, and sporting equipment, such as canoes and kayaks.

[0088] In polymer molding applications, including rotomolding and injection molding applications, solutions are continually sought to enable material cost reduction, for example, from downgauging (i.e., using thinner wall thicknesses) or by reducing or eliminating relatively expensive materials. Traditionally, downgauging can be achieved by using polymer resins with higher densities, but increasing density typically reduces environmental stress crack resistance (ESCR). Therefore, there is a need for polyethylene compositions that can be utilized in rotomolding applications that exhibit a balance of stiffness and ESCR properties that meet customer and industry demands.

[0089]

[0010] Embodiments of the present disclosure can provide polyethylene compositions comprising a broad comonomer distribution such that, when utilized in rotomolding applications, the polyethylene compositions can exhibit desirable stiffness without compromising ESCR or impact properties. Thus, embodiments of the present disclosure can provide polyethylene compositions that, when utilized in rotomolding applications, can provide a balance of stiffness and ESCR properties, potentially enabling reduced material costs. Furthermore, the polyethylene compositions described herein can exhibit flow and processability properties that enable easier fabrication methods and more complex article designs.

[0090] In embodiments, the polyethylene compositions may be blended with one or more polyolefins to produce blends that can be rotomolded into articles. In embodiments, the blends may include blends of the polyethylene compositions described herein with one or more of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE). In embodiments, providing a polyethylene composition comprising the polyethylene compositions described herein or a blend comprising the polyethylene compositions described herein may provide a balance of stiffness and ESCR properties when utilized in rotomolding applications.

[0091] It should be understood that the polyethylene compositions or blends comprising the polyethylene compositions described herein may further comprise one or more additives known to those skilled in the art, such as plasticizers, stabilizers including viscosity stabilizers, hydrolysis stabilizers, primary and secondary antioxidants, ultraviolet absorbers, antistatic agents, dyes, pigments, or other colorants, inorganic fillers, flame retardants, lubricants, reinforcing agents such as glass fibers and flakes, synthetic (e.g., aramid) fibers or pulp, foaming or expanding agents, processing aids, slip additives, antiblocking agents such as silica or talc, release agents, tackifying resins, hindered amine light stabilizers (HALS), or combinations of two or more thereof. Inorganic fillers such as calcium carbonate may also be incorporated into the polyethylene composition. In some embodiments, the polyethylene composition may comprise up to 5 weight percent of such additional additives, based on the total weight of the polyethylene composition. In embodiments, the total amount of additives in the polyethylene composition may be 0.2 wt% to 5 wt%, 0.2 wt% to 4 wt%, 0.2 wt% to 3 wt%, 0.2 wt% to 2 wt%, 0.2 wt% to 1 wt%, 0.2 wt% to 5 wt%, 0.5 wt% to 5 wt%, 0.5 wt% to 4 wt%, 0.5 wt% to 3 wt%, 0.5 wt% to 2 wt%, 0.5 wt% to 1 wt%, 1 wt% to 5 wt%, 1 wt% to 4 wt%, 1 wt% to 3 wt%, 1 wt% to 2 wt%, 2 wt% to 5 wt%, 2 wt% to 4 wt%, 2 wt% to 3 wt%, 3 wt% to 5 wt%, 3 wt% to 4 wt%, or 4 wt% to 5 wt%, based on the total weight of the polyethylene composition. Incorporation of the additives can be carried out by any known process, such as, for example, dry blending, extrusion of a mixture of the various components, conventional masterbatch techniques, etc.

[0092] Various methods of making embodiments of articles, such as rotomolded articles, from the polyethylene compositions disclosed herein are familiar to those skilled in the art. Various methodologies are contemplated for making embodiments of rotomolded articles.

[0093] Test Method Test methods include:

[0094] Melt Index The melt index I2 (or I2) and I of the polymer sample 10 (or I10) were measured according to ASTM D-1238 (Method B) at 190°C and loads of 2.16 kg and 10 kg, respectively. The values ​​are reported in g / 10 min. Fractions of polymer samples can be measured by recovering product polymer from reactors producing specific fractions or portions of the polymer composition. For example, a first polyethylene fraction can be recovered from a reactor producing a lower density, higher molecular weight component of the polymer composition. Prior to melt index measurement, the polymer solution is dried under vacuum.

[0095] density Samples for density measurements were prepared according to ASTM D4703. Measurements were performed according to ASTM D792, Method B, within 1 hour of sample pressing.

[0096] Creep Zero Shear Viscosity Measurement Method Zero shear viscosity is obtained via creep testing conducted on an AR-G2 stress-controlled rheometer (TA Instruments, New Castle, Del.) using 25 mm diameter parallel plates at 190°C. The rheometer oven is set to the test temperature for at least 30 minutes before zeroing the fixture. At the test temperature, a compression-molded sample disc is inserted between the plates and allowed to equilibrate for 5 minutes. The upper plate is then lowered to 50 μm above the desired test gap (1.5 μm). Any excess material is trimmed away, and the upper plate is lowered to the desired gap. Measurements are performed under a nitrogen purge at a flow rate of 5 L / min. The initial creep time is set to 2 hours.

[0097] To ensure that the steady-state shear rate was low enough in the Newtonian region, all of the samples were subjected to a constant low shear stress of 20 Pa. The resulting steady-state shear rate was 10 for the samples in this study. -3 ~10 -4 s -1The steady state is determined by taking a linear regression of all data within the last 10% time window of a plot of log(J(t)) vs. log(t), where J(t) is the creep compliance and t is the creep time. If the slope of the linear regression is greater than 0.97, steady state is considered to have been reached, and the creep test is then stopped. In this study, in all cases, the slope meets the criterion within 2 hours. The steady-state shear rate is determined from the slope of the linear regression of all data points within the last 10% time window of a plot of ε vs. t (ε is strain). The zero-shear viscosity is determined from the ratio of the applied stress to the steady-state shear rate.

[0098] To determine whether the specimen degrades during the creep test, perform small amplitude oscillatory shear tests on the same specimen before and after the creep test at 0.1 to 100 rad / s. Compare the complex viscosity values ​​from the two tests. If the difference in viscosity at 0.1 rad / s is greater than 5%, consider the specimen to have degraded during the creep test and discard the results.

[0099] Gel Permeation Chromatography (GPC) The chromatography system consisted of a PolymerChar GPC-IR (Valencia, Spain) high-temperature GPC chromatograph equipped with an internal IR5 infrared detector (IR5). The autosampler oven compartment was set to 160°C, and the column compartment was set to 150°C. The columns used were four Agilent "Mixed A" 30 cm 20-micron linear mixed-bed columns and a 20-um precolumn. The chromatography solvent used was 1,2,4-trichlorobenzene containing 200 ppm butylated hydroxytoluene (BHT). The solvent source was nitrogen sparged. The injection volume used was 200 microliters, and the flow rate was 1.0 milliliters / minute.

[0100] The GPC column set was calibrated using 21 narrow molecular weight distribution polystyrene standards ranging from 580 to 8,400,000, arranged in six "cocktail" mixtures with at least 10-fold spacing between individual molecular weights. The standards were purchased from Agilent Technologies. Polystyrene standards were prepared at 0.025 grams in 50 milliliters of solvent for molecular weights above 1,000,000 and 0.05 grams in 50 milliliters of solvent for molecular weights below 1,000,000. The polystyrene standards were dissolved at 80°C for 30 minutes with gentle agitation. The peak molecular weights of the polystyrene standards were converted to polyethylene molecular weights using Equation 1 (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)).

[0101]

number

[0102] A fifth-order polynomial was used to fit each polyethylene equivalent calibration point. A small adjustment to A (approximately 0.375 to 0.445) was made to ensure that the linear homopolymer polyethylene standard had a 120,000 Mw (GPC) Corrections were made for column resolution and band broadening effects as given by

[0103] Total plate counts for the GPC column set were performed using decane (prepared at 0.04 g in 50 milliliters of TCB and dissolved for 20 minutes with gentle stirring). Plate counts (Equation 2) and symmetry (Equation 3) were measured with a 200 microliter injection according to the following equations:

[0104]

number

[0105]

number

[0106] Samples were prepared in a semi-automated fashion using PolymerChar "Instrument Control" software, with a target sample weight of 2 mg / mL, and solvent (containing 200 ppm BHT) added via a PolymerChar high-temperature autosampler to a pre-nitrogen-sparged septa-capped vial. Samples were dissolved at 160°C for 2 hours under "slow" shaking.

[0107] Mn (GPC) , Mw (GPC) , and Mz (GPC) The calculation of was based on GPC results using the internal IR5 detector (measurement channel) of the PolymerChar GPC-IR chromatograph according to Equations 4-6 using PolymerChar GPCOne™ software, baseline-subtracted IR chromatograms at each equally spaced data collection point (i), and polyethylene equivalent molecular weights obtained from a narrow standard calibration curve for point (i) of Equation 1.

[0108]

number

[0109] To monitor deviations over time, a flow rate marker (decane) was introduced into each sample via a micropump controlled by the PolymerChar GPC-IR system. This flow rate marker (FM) was used to linearly correct the pump flow rate (flow rate (apparent)) for each sample by RV-matching the respective decane peak in the sample (RV (FM sample)) with that of the decane peak in the narrow standard calibration (RV (FM calibrated)). Any change in the time of the decane marker peak is then assumed to be related to a linear shift in flow rate (flow rate (effective)) throughout the run. To facilitate the highest accuracy in the RV measurement of the flow rate marker peaks, a least-squares fitting routine is used to fit the peaks in the flow rate marker concentration chromatogram to a quadratic equation. The first derivative of the quadratic equation is then used to solve for the true peak position. After calibrating the system based on the flow rate marker peaks, the effective flow rate (relative to the narrow reference calibration) is calculated as Equation 7. Processing of the flow rate marker peaks was performed via PolymerChar GPCOne™ software. The acceptable flow correction is one in which the effective flow rate should be within + / - 0.5% of the apparent flow rate.

[0110]

number

[0111] Improved Method for Comonomer Content Analysis (iCCD) An improved comonomer content analysis method (iCCD) was developed in 2015 (Cong and Parrott et al., WO 2017040127(A1)). iCCD experiments were performed using a crystallization elution fractionation (CEF) instrument (PolymerChar, Spain) equipped with an IR-5 detector (PolymerChar, Spain) and a two-angle light scattering detector model 2040 (Precision Detectors, now Agilent Technologies). A 5 cm or 10 cm (length) x 1 / 4 inch (ID) guard column packed with 20-27 micron glass on stainless steel (MoSCi Corporation, USA) was placed immediately before the IR-5 detector in the detector oven. Ortho-dichlorobenzene (ODCB, 99% anhydrous grade or technical grade) was used. Silica gel 40 (particle size 0.2–0.5 mm, catalog number 10181-3) was obtained from EMD Chemicals (which could be used to dry the ODCB solvent beforehand). The dried silica was packed into three empty HT-GPC columns to further purify the ODCB as the eluent. The CEF instrument was equipped with an autosampler with N2 purge capability. ODCB was sparged with dry nitrogen (N2) for 1 h before use. Samples were prepared at 4 mg / mL using the autosampler (unless otherwise specified) at 160 °C for 1 h with shaking. The injection volume was 300 μL. The temperature profile for the iCCD was: crystallization from 105 °C to 30 °C at 3 °C / min, thermal equilibration at 30 °C for 2 min (including setting the soluble fraction elution time to 2 min), and elution from 30 °C to 140 °C at 3 °C / min. The flow rate during crystallization was 0.0 mL / min. The flow rate during elution was 0.50 mL / min. Data is collected at 1 data point / second.

[0112] The iCCD column was packed with gold-coated nickel particles (Bright 7GNM8-NiS, Nippon Chemical Industrial Co.) in a 15 cm (length) × ¼ inch (ID) stainless steel tube. Column packing and conditioning were performed using a slurry method according to reference (Cong, R.; Parrott, A.; Hollis, C.; Cheatham, M. International Publication No. 2017040127(A1)). The final pressure using TCB slurry packing was 150 bar.

[0113] The ODCB reference material is a linear homopolymer polyethylene (comonomer content: zero, melt index (I2): 1.0, polydispersity: Mw (GPC) / Mn (GPC) Column temperature calibration was performed by using a mixture of ethanol (approximately 2.6, 1.0 mg / mL) and eicosane (2 mg / mL) in conventional gel permeation chromatography. The iCCD temperature calibration consisted of four steps: (1) calculating the delay volume, defined as the temperature offset between the measured peak elution temperatures of eicosane minus 30.00°C; (2) subtracting the temperature offset of the elution temperatures from the iCCD raw temperature data (note that this temperature offset is a function of experimental conditions such as elution temperature and elution flow rate); (3) constructing a linear calibration line converting elution temperatures over the range of 30.00°C to 140.00°C, such that a linear homopolymer polyethylene reference material has a peak temperature at 101.0°C and eicosane has a peak temperature of 30.0°C; and (4) linearly extrapolating elution temperatures below 30.0°C for the soluble fraction measured isothermally at 30°C by using an elution heating rate of 3°C / min according to reference (Cerk and Cong et al., U.S. Pat. No. 9,688,795).

[0114] Comonomer content versus iCCD elution temperature was constructed using 12 reference materials (ethylene homopolymers and single-site metallocene-catalyzed ethylene-octene random copolymers with ethylene equivalent weight average molecular weights ranging from 35,000 to 128,000). All of these reference materials were analyzed at 4 mg / mL using the same methodology as previously specified. The reported elution peak temperatures were linearly fit to the linear equation y = -6.3515x + 101.00, where y represents the iCCD elution temperature, x represents octene mole %, and R 2 was 0.978.

[0115] The molecular weights of the polymer and polymer fractions were determined directly from the LS detector (at a 90-degree angle) and the concentration detector (IR-5) according to the Rayleigh-Gans-Debys approximation (Striegel and Yau, "Modern Size Exclusion Liquid Chromatogram," pp. 242 and 263) by assuming a form factor of 1 and all virial coefficients of zero. An integration window was set to integrate all chromatograms over the elution temperature range of 23.0 to 120 °C (temperature calibration specified above).

[0116] Molecular weight (Mw (iCCD) ) involves four steps: (1) Step of measuring the inter-detector offset. The offset is defined as the geometric volume offset between the LS detector and the concentration detector. It is calculated as the difference in elution volume (mL) of the polymer peak between the concentration detector and the LS chromatogram. This is converted to a temperature offset by using the elution heat rate and elution flow rate. A linear high-density polyethylene (comonomer content zero, melt index (I2) 1.0, polydispersity M w / M nConventional gel permeation chromatography (GPC) is used (approximately 2.6). The experimental conditions are the same as those for the conventional iCCD method described above, except for the following parameters: crystallization from 140°C to 137°C at 10°C / min, thermal equilibration at 137°C for 1 minute as the soluble fraction elution time, soluble fraction (SF) time of 7 minutes, and elution from 137°C to 142°C at 3°C / min. The flow rate during crystallization is 0.0 mL / min. The flow rate during elution is 0.80 mL / min. The sample concentration is 1.0 mg / mL. (2) Shift each LS data point in the LS chromatogram to correct for inter-detector offset before integration. (3) The baseline-subtracted LS and concentration chromatograms are integrated over the elution temperature range of step (1). The MW detector constant is calculated using HDPE samples of known MW in the range of 100,000 to 140,000 MW and the area ratio of the LS and concentration integrated signals. (4) The Mw of the polymer was calculated by using the ratio of the integrated light scattering detector (at a 90-degree angle) to the concentration detector and using the MW detector constant.

[0117] The half-width calculation is defined as the temperature difference between the forward and backward temperatures at half the maximum peak height, where the forward temperature at half the maximum peak is searched forward from 35.0°C, and the backward temperature at half the maximum peak is searched backward from 119.0°C.

[0118] Zero-shear viscosity ratio (ZSVR) ZSVR is calculated by the equivalent weight average molecular weight (Mw (GPC) ) is defined as the ratio of the zero shear viscosity (ZSV) of the branched polyethylene material to the ZSV of the linear polyethylene material.

[0119]

number

[0120] ZSV values ​​were obtained from creep tests at 190°C using the method described above.(GPC) The ZSV of linear polyethylene and its Mw (GPC) A correlation between ZSV-Mw and ZSV-Mw was established based on a series of linear polyethylene reference materials. (GPC) A discussion of this relationship can be found in ANTEC Proceedings: Karjala, Teresa P., Sammler, Robert L., Mangnus, Marc A., Hazlitt, Lonnie G., Johnson, Mark S., Hagen, Charles M. Jr., Huang, Joe W. L., Reichek, Kenneth N., 'Detection of low levels of long-chain branching in polyolefins', Annual Technical Conference - Society of Plastics Engineers (2008), 66th pp. 887-891.

[0121] Dynamic Rheological Analysis To characterize the rheological behavior of substantially linear ethylene polymers, S. Lai and G.W. Knight (ANTEC '93 Proceedings, Insite™ Technology Polyolefins (ITP)—New Rules in the Structure / Rheology Relationship of Ethylene & Ethylene Copolymers, New Orleans, La., May 1993) introduced a new rheological measurement, the Dow Rheology Index (DRI), which represents the "normalized relaxation time as a result of long chain branching" of a polymer. S. Lai et al. (ANTEC '94, Dow Rheology Index (DRI) for Insite™ Technology Polyolefins (ITP): Unique structure-Processing Relationships, pp. 1814-1815) defined the DRI as the extent to which the rheology of ethylene-octene copolymers known as ITPs (Dow's Insite Technology Polyolefins), which incorporate long-chain branching in the polymer backbone, deviates from the rheology of conventional linear homogeneous polyolefins reported to have no long-chain branching (LCB), by the following normalized equation:

[0122]

number

[0123]

number

[0124] Dynamic rheology measurements are performed in an inert atmosphere in dynamic mode on a dynamic rheometer (e.g., a TA Instruments ARES rheometer) equipped with 25 mm diameter parallel plates, in accordance with ASTM D4440. For all experiments, the rheometer is thermally stabilized at 190°C for at least 30 minutes before inserting a compression-molded sample, appropriately stabilized (using antioxidant additives), onto the parallel plates. The plates are then closed with a positive normal force registered on the meter to ensure good contact. After approximately 5 minutes at 190°C, the plates are gently compressed and excess polymer around the plates is trimmed. An additional 10 minutes is allowed for thermal stability and normal force to return to zero. Thus, all measurements are performed after equilibrating the sample at 190°C for approximately 15 minutes and are performed under a full nitrogen blanket.

[0125] Two strain sweep (SS) experiments are first conducted at 190 °C to determine the linear viscoelastic strain that produces a torque signal that is greater than 10% of the transducer's lower scale across the entire frequency range (e.g., 0.01–100 rad / s). The first SS experiment is conducted at a low applied frequency of 0.1 rad / s. This test is used to determine torque sensitivity at low frequencies. The second SS experiment is conducted at a high applied frequency of 100 rad / s. This is to ensure that the selected applied strain is well within the polymer's linear viscoelastic region so that the oscillatory rheology measurements do not induce structural changes to the polymer during testing. Additionally, a time sweep (TS) experiment is conducted at a low applied frequency of 0.1 rad / s at the selected strain (determined by the SS experiment) to check the sample's stability during testing.

[0126] Storage modulus (or elastic modulus), loss modulus (or viscous modulus) (G''), complex modulus (G * ), complex viscosity (η *), and tan δ (ratio of loss modulus to storage modulus, G′VG′) were obtained as a function of frequency (ω) at a given temperature (e.g., 190° C.).

[0127] Instrumented Dart Impact The instrumented dart impact method is measured on compression-molded plaque specimens according to ASTM D3763 using an Instron CEAST 9350 impact tester. Tests are performed using a 12.7 mm diameter tip with a hemispherical head. The instrument is equipped with an environmental chamber for testing at low or high temperatures. Typical specimen size is 100 mm x 100 mm. The standard test speed is 200 m / min. The plaque thickness is 3.0 mm. Tests were performed at a temperature of -40°C.

[0128] Comonomer Distribution Breadth Index (CDBI) CDBI50 (Composition Distribution Breadth Index) is a parameter used to characterize resin composition distribution. It is a quantitative measure of the breath of the distribution. CDBI50 is defined as the weight percent of copolymer molecules having a comonomer content within 50% (i.e., 50% on either side) of the median total molar comonomer content (Cmed). The Cmed composition corresponds to the composition at which the cumulative integral equals 0.5. The difference between the cumulative integrals at compositions 0.5 Cmed and 1.5 Cmed is the CDBI50 of the copolymer. The CDBI50 of a resin can be determined using separation techniques such as iCCD, ATREF, and CEF. CDBI50 values ​​range from 0 to 1, with larger values ​​indicating a narrower comonomer distribution and smaller values ​​indicating a broader comonomer distribution. Following a similar principle, CDBI25 is defined as the weight percent of copolymer molecules having a comonomer content within 25% of the median total molar comonomer content (Cmed). The difference between the cumulative integrals at compositions 0.75 Cmed and 1.25 Cmed is the CDBI25 of the copolymer.

[0129] CDBI50 is calculated from the data obtained from the CEF using the method described in WO 93 / 03093, which is incorporated herein by reference. CDBI represents a comparison of the comonomer distribution in a polymer with that expected from a Bernoulli distribution.

[0130] Environmental Stress Cracking Resistance (ESCR) The ESCR of the resins was measured according to ASTM D 1693-13. Test specimens were compression molded into plaques according to ASTM Method D4703-10a (Procedure C). 38 mm x 13 mm test specimens were cut using a die cut within 24 hours after the sheets were prepared. The thickness of the test specimens depended on the ESCR method (A or B) being performed. Samples were tested using both Method A. Method A used 3.15 mm thick test specimens, while Method B used 1.90 mm thick test specimens.

[0131] To perform the test, a controlled defect (notch) was placed on one surface of each specimen. Ten specimens were bent and exposed to the action of a surfactant (Igepal® CO-630) at 50°C. The concentration of the surfactant was 10% in water. The number of cracked specimens was monitored as a function of time. Failure was recorded and the result F50 corresponds to the time taken for 50% of the specimens to break (calculated by linear regression). [Example]

[0132] The following examples illustrate features of the present disclosure and are not intended to limit the scope of the disclosure. The following experiments analyzed the performance of embodiments of the polyethylene compositions described herein.

[0133] Example 1: Preparation of polyethylene compositions 1 to 4 Polyethylene Compositions 1-4 described according to one or more embodiments of the Detailed Description were prepared by the methods described below utilizing the catalysts and reactors.

[0134] All raw materials (monomer and comonomer) and process solvents (Shellsol SBP 100-140) were purified with molecular sieves before being introduced into the reaction environment. Hydrogen was supplied under pressure as a high-purity grade without further purification. The reactor monomer feed stream was pressurized above the reaction pressure via a mechanical compressor. The solvent and comonomer feeds were pressurized above the reaction pressure via pumps. The individual catalyst components were manually batch diluted with purified solvent and pressurized to the reaction pressure described above. All reaction feed streams were measured with mass flow meters and independently controlled by a computerized automated valve control system.

[0135] Two reactor systems were used in a series configuration. Each continuous solution polymerization reactor utilized a liquid-filled, non-adiabatic, isothermal, circulating, isothermal continuous stirred tank reactor (CSTR). Independent control of all fresh solvent, monomer, comonomer, hydrogen, and catalyst component feeds was possible. All fresh feed streams to each reactor (solvent, monomer, comonomer, and hydrogen) were temperature controlled to maintain a single solution phase by passing the feed streams through heat exchangers. Fresh feeds were controlled so that each injector received half of the total fresh feed mass flow rate. Catalyst components were injected into the polymerization reactor through injection stingers. Catalyst feed was computer-controlled to maintain the monomer conversion of each reactor at a specific target. The cocatalyst component was fed to the primary catalyst component based on a specific calculated molar ratio.

[0136] The effluent from the first polymerization reactor (containing solvent, monomer, comonomer, hydrogen, catalyst components, and polymer) exited the first reactor and was added to the second reactor.

[0137] The second reactor effluent entered a zone where it was deactivated by addition and reaction with a suitable reagent (water). At this same reactor exit location, other additives were added for polymer stabilization (typical antioxidants suitable for stabilization during extrusion and film fabrication, such as octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, tetrakis(methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate))methane, and tris(2,4-di-tert-butyl-phenyl)phosphite).

[0138] Following catalyst deactivation and additive addition, the reactor effluent entered a devolatilization system where the polymer was removed from the non-polymer stream. The isolated polymer melt was pelletized and collected. The non-polymer stream was removed from the system.

[0139] Reactor flow feed data correspond to the values ​​in Table 1. The data are presented to allow for the complexity of the solvent recycle system and to make the reaction system easier to treat as a once-through flow diagram. Table 2 shows the catalysts referenced in Table 1.

[0140] [Table 1] * Solvent = Shellsol SBP 100-140

[0141] [Table 2]

[0142] Example 2: Preparation of polyethylene composition 5 Polyethylene composition 5, as described according to one or more embodiments of the Detailed Description, was prepared by the method described below utilizing a catalyst and reactor.

[0143] Polyethylene Composition 5 was prepared utilizing a continuous additive (CA-300 from Univation Technologies, LLC, Houston, Texas, USA), (methylaluminoxane (MAO) activator, ethylene, hexene, mineral oil (Sonneborn HYDROBRITE 380 PO White), hydrogen gas, and ICA (a mixture consisting essentially of at least 95%, alternatively at least 98%, 2-methylbutane (isopentane, CH(CH)CH(CH)), with minor components including at least pentane (CH(CH)CH)).

[0144] The catalyst used was bis(n-propylcyclopentadienyl)hafnium dimethyl (CAS No. 255885-01-9, available from BOC Sciences, a brand of BOCSCI Inc., Shirley, New York, USA). To prepare the spray-dried catalyst system utilized to produce Polyethylene Composition 5, a Buchi B-290 mini spray dryer housed within a nitrogen-atmosphere glove box was set at a temperature of 165°C, with an outlet temperature set at 60-70°C. Fumed silica (Cabosil TS-610, 3.2 g), MAO in toluene (10 wt%, 21 g), and bis(propylcyclopentadienyl)hafnium dimethyl (0.11 g) were mixed in toluene (72 g). The resulting mixture was introduced into an atomizer to generate droplets, which were then contacted with a stream of hot nitrogen gas to evaporate the liquid and thereby produce a powder. The powder was separated from the gas mixture in a cyclone separator, and sd-Cat-1 was collected as a powder (3.81 g) in a conical can. sd-Cat-1 can be fed to the gas-phase polymerization reactor as a dry powder or as a slurry in mineral oil.

[0145] To produce Polyethylene Composition 5, the spray-dried catalyst system prepared as described above was fed as a dry powder to a fluidized-bed gas-phase polymerization dual-reactor system comprising two Pilot FB-GPP reactors (the first reactor and the second reactor) containing a bed of polyethylene granules. Polymerization was initiated in the first reactor by continuously feeding the dry sd-Cat-1 catalyst powder, ethylene, hexene, and hydrogen (H2) into the fluidized bed of polyethylene granules while feeding continuity additive CA-300 as a 20 wt% solution in mineral oil at a feed rate of 3 milliliters per hour (mL / h). A unimodal polyethylene polymer was produced and removed from the first reactor, containing active catalyst. The removed material was transferred to the second reactor using the second reactor gas as a transport medium. The feed ethylene, hexene, and hydrogen (excluding fresh sd-Cat-1) were fed to the second reactor. Inert gas, nitrogen, and isopentane made up the remaining gas composition in both the first and second reactors. The properties of the polyethylene component discharged from the first reactor were measured directly on a sample of the granular resin of the polyethylene component produced in the first reactor before the polyethylene component was transferred to the second reactor. Prior to the measurements, the granular resin was stabilized with 2000 ppmw of butylated hydroxytoluene (BHT). The polymerization conditions for the first and second reactors and the properties of the granular resin from the first reactor are reported in Table 3. The polymer discharged from the second reactor was blended as granules with 4950 ppm by weight (ppmw) of antioxidant and UV stabilizer additives available from Solvay. This combination was fed into a continuous mixer (LCM-100 manufactured by Kobe Steel, Ltd.), which was connected to a gear pump and closed, equipped with a melt filtration device and an underwater pelletizing system to separately produce strands that were chopped into pellets. The overall properties of polyethylene composition 5 were measured directly on it.

[0146] [Table 3]

[0147] Example 3: Comparative Compositions A to C Table 4 identifies the commercially available polyethylene compositions of Comparative Polyethylene Compositions A-C.

[0148] [Table 4]

[0149] Example 4: Comparative Compositions D to F Comparative polyethylene compositions D to F were prepared using the catalysts and reactors according to the methods described below.

[0150] All raw materials (monomers and comonomers) and process solvents (high-purity narrow-boiling range isoparaffinic solvent, Isopar-E) were purified with molecular sieves before being introduced into the reaction environment. Hydrogen was supplied under pressure as a high-purity grade without further purification. The reactor monomer feed stream was pressurized above the reaction pressure via a mechanical compressor. The solvent and comonomer feeds were pressurized above the reaction pressure via pumps. The individual catalyst components were manually batch diluted with purified solvent and pressurized to the above reaction pressure. All reaction feed streams were measured with mass flow meters and independently controlled by a computerized automated valve control system.

[0151] Two reactor systems were used in a series configuration. Each continuous solution polymerization reactor consisted of a liquid-filled, non-adiabatic, isothermal circulation loop reactor, simulating a heat-removing continuous stirred tank reactor (CSTR). Independent control of all fresh solvent, monomer, comonomer, hydrogen, and catalyst component feeds was possible. All fresh feed streams to each reactor (solvent, monomer, comonomer, and hydrogen) were temperature controlled to maintain a single solution phase by passing the feed streams through heat exchangers. The total fresh feed to each polymerization reactor was injected into the reactor at two locations, with reactor volumes approximately equal between each injection location. Fresh feed was controlled, with each injector receiving half of the total fresh feed mass flow rate. Catalyst components were injected into the polymerization reactor through injection stingers. The feed of the primary catalyst components was computer-controlled to maintain the monomer conversion of each reactor at a specific target. The cocatalyst components were fed to the primary catalyst component based on a specific calculated molar ratio. Immediately after each reactor feed injection point, the feed stream was mixed with the contents of the circulation polymerization reactor using a static mixing element. The contents of each reactor were continuously circulated through a heat exchanger that removed most of the heat of reaction and maintained an isothermal reaction environment at a specified temperature on the coolant side. Circulation around each reactor loop was provided by a pump.

[0152] In the dual series reactor configuration, the effluent from the first polymerization reactor (containing solvent, monomer, comonomer, hydrogen, catalyst components, and polymer) exited the first reactor loop and was added to the second reactor loop.

[0153] The second reactor effluent entered a zone where it was inactivated by addition and reaction with a suitable reagent (water). At this same reactor exit location, other additives were added to stabilize the polymer (typical antioxidants suitable for stabilization during extrusion and film fabrication, such as octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, tetrakis(methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate))methane, and tris(2,4-di-tert-butyl-phenyl)phosphite).

[0154] Following catalyst deactivation and additive addition, the reactor effluent entered a devolatilization system where polymer was removed from the non-polymer stream. The isolated polymer melt was pelletized and collected. The non-polymer stream passed through various equipment that separated most of the ethylene, which was removed from the system. Most of the solvent and unreacted comonomer were recycled to the reactor after passing through a purification system. A small amount of solvent and comonomer was purged from the process.

[0155] Reactor flow feed data is shown in Table 5. The data is presented to allow for the complexity of the solvent recycle system and to allow the reaction system to be more easily treated as a once-through flow diagram. Table 6 shows the catalysts referenced in Table 5.

[0156] [Table 5]

[0157] [Table 6]

[0158] Comparative polyethylene composition F was prepared utilizing a catalyst and reactor by the method described below.

[0159] All raw materials (monomers and comonomers) and process solvents (high-purity narrow-boiling-range isoparaffinic solvent, Isopar-E) were purified with molecular sieves before being introduced into the reaction environment. Hydrogen was supplied under pressure as a high-purity grade without further purification. The reactor monomer feed stream was pressurized above the reaction pressure via a mechanical compressor. The solvent and comonomer feeds were pressurized above the reaction pressure via pumps. The individual catalyst components were manually batch diluted with purified solvent and pressurized to the reaction pressure described above. All reaction feed streams were measured with mass flow meters and independently controlled by a computerized valve control system.

[0160] Two reactor systems were used in a parallel configuration. Each continuous solution polymerization reactor consisted of a liquid-filled, non-adiabatic, isothermal circulating loop reactor, replicating a heat-removing continuous stirred tank reactor (CSTR). Independent control of all fresh solvent, monomer, comonomer, hydrogen, and catalyst component feeds was possible. All fresh feed streams to each reactor (solvent, monomer, comonomer, and hydrogen) were temperature-controlled to maintain a single solution phase by passing the feed streams through heat exchangers. The total fresh feed to each polymerization reactor was injected into the reactor at two locations, with reactor volumes approximately equal between each injection location. Fresh feed was controlled, with each injector receiving half of the total fresh feed mass flow rate. Catalyst components were injected into the polymerization reactor through specially designed injection stingers. The feed of the primary catalyst components was computer-controlled to maintain the monomer conversion of each reactor at a specific target. The cocatalyst components were fed to the primary catalyst component based on a specific calculated molar ratio. Immediately after each reactor feed injection point, the feed stream was mixed with the contents of the circulation polymerization reactor using a static mixing element. The contents of each reactor were continuously circulated through a heat exchanger that removed most of the heat of reaction and maintained an isothermal reaction environment at a specified temperature on the coolant side. Circulation around each reactor loop was provided by a pump.

[0161] The effluent streams from the first and second polymerization reactors were combined before any additional processing. This combined final reactor effluent entered a zone where the effluent was inactivated by addition and reaction with a suitable reagent (water). At this same reactor exit point, other additives were added to stabilize the polymer (typical antioxidants suitable for stabilization during extrusion and blown film fabrication, such as octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, tetrakis(methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate))methane, and tris(2,4-di-tert-butyl-phenyl)phosphite).

[0162] Following catalyst deactivation and additive addition, the reactor effluent entered a devolatilization system where polymer was removed from the non-polymer stream. The isolated polymer melt was pelletized and collected. The non-polymer stream passed through various pieces of equipment, which separated most of the ethylene, which was removed from the system. Most of the solvent and unreacted comonomer were recycled to the reactor after passing through a purification system. Small amounts of solvent and comonomer were purged from the process.

[0163] The reactor flow feed data is shown in Table 7. The data is presented to allow for the complexity of the solvent recycle system and to allow the reaction system to be more easily treated as a once-through flow diagram. Table 6 shows the catalysts referenced in Table 7.

[0164] [Table 7]

[0165] Example 5: Comparison of polyethylene compositions 1 to 5 with comparative compositions A to F Comparative properties of polyethylene compositions 1-5 and comparative compositions A-F were measured and calculated according to the test methods described herein and are reported in Tables 8-10. Figure 1 graphically depicts the elution profile of polyethylene composition 1 according to one or more embodiments described herein.

[0166] [Table 8] 1 Weight fraction of components eluting at temperatures above 95°C in the elution profile based on improved comonomer composition distribution (ICCD)

[0167] [Table 9]

[0168] [Table 10]

[0169] It will be apparent that modifications and variations are possible without departing from the scope of the present disclosure, as defined in the appended claims. More specifically, while certain aspects of the present disclosure have been identified herein as preferred or particularly advantageous, it is not intended that the present disclosure be necessarily limited to these aspects.

Claims

1. 1. A polyethylene composition comprising: a first polyethylene fraction region defined by a region in an elution profile by improved comonomer composition distribution (iCCD) analysis in the temperature range of 70°C to 97°C; a first peak in the temperature range of 70°C to 97°C in the elution profile; a second polyethylene fraction region defined by a region in said elution profile ranging in temperature from 97°C to 110°C; a second peak in the temperature range of 97°C to 110°C in the elution profile; 0.935 g / cm ３ ~0.955g / cm ３ Density of 1.0 g / 10 min to 10.0 g / 10 min, melt index (I ２ ) and the ratio of the first polyethylene fraction area to the second polyethylene fraction area is less than 2.0; 1. A polyethylene composition comprising: a polyethylene composition having an overall molecular weight (Mw(iCCD)) as determined by iCCD; a first polyethylene fraction having a first fraction molecular weight (Mw(iCCD, 70°C-97°C)) as determined by iCCD; and a ratio of the overall molecular weight (Mw(iCCD)) to the molecular weight of the first fraction (Mw(iCCD, 70°C-97°C)) of less than 0.

9.

2. The ratio of the weight average molecular weight to the number average molecular weight (Mw （ＧＰＣ） / Mn （ＧＰＣ） 2. The polyethylene composition of claim 1 , having a molecular weight distribution expressed as

3. 3. The polyethylene composition according to claim 1 or 2, wherein the second polyethylene fraction region may comprise 30% to 80% of the total area of ​​the elution profile.

4. The polyethylene composition according to any one of claims 1 to 3, having a CDBI50 of 50% or less.

5. 5. The polyethylene composition according to any one of claims 1 to 4, having a zero shear viscosity ratio of less than 2.

0.

6. 6. The polyethylene composition according to any one of claims 1 to 5, having an ESCR F50(10%, A) of more than 300 hours, measured in accordance with ISO 14449-1.

7. 1. A polyethylene composition comprising: A first polyethylene fraction in the temperature range of 70°C to 97°C in an elution profile by improved comonomer composition distribution (iCCD) analysis, comprising a first peak, and the molecular weight (Mw （ｉＣＣＤ、７０℃～９７℃） a first polyethylene fraction having a a second polyethylene fraction in the temperature range of 97°C to 110°C in the elution profile, the second polyethylene fraction comprising a second peak; The total molecular weight (Mw （ｉＣＣＤ） ), 0.935g / cm ３ ~0.955g / cm ３ Density of 1.0 g / 10 min to 10.0 g / 10 min, melt index (I ２ ) The total molecular weight (Mw （ｉＣＣＤ） The molecular weight (Mw) of the first fraction （ｉＣＣＤ、７０℃～９７℃） ) is less than 0.

9.

8. The ratio of the weight average molecular weight to the number average molecular weight (Mw （ＧＰＣ） / Mn （ＧＰＣ） 8. The polyethylene composition of claim 7, having a molecular weight distribution expressed as

9. 9. The polyethylene composition according to claim 7 or 8, wherein the second polyethylene fraction region may comprise 30% to 80% of the total area of ​​the elution profile.

10. The polyethylene composition according to any one of claims 7 to 9, having a CDBI50 of 50% or less.

11. 11. The polyethylene composition according to any one of claims 7 to 10, wherein the ratio of the first mass fraction to the second mass fraction is less than 2.

0.

12. 12. The polyethylene composition according to any one of claims 7 to 11, having a zero shear viscosity ratio of less than 2.

0.

13. 13. The polyethylene composition according to any one of claims 7 to 12, having an ESCR F50(10%, A) measured in accordance with ISO 14449-1 D1693 of more than 300 hours.

14. A method for producing a rotomoulded article comprising the polyethylene composition of any one of claims 1 to 13.

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