Linear high-density polyethylene composition and rotationally molded article

Abstract

A solution-phase polymerization process using a metallocene catalyst in the first reactor and a Ziegler-Natta catalyst in the second reactor yielded 0.940 g / cm³. 3 A polyethylene composition with the above density and a melt index I2 of less than 3.0 g / 10 min is obtained. When prepared as plaque, the polyethylene composition has a good combination of environmental stress crack resistance, IZOD impact strength, and stiffness. The polyethylene composition containing the first ethylene copolymer and the second ethylene copolymer also has a good processing window when preparing rotationally molded test specimens.

Description

[Technical Field]

[0001] This invention relates to polyethylene compositions suitable for use in rotational molded articles. The invention also relates to a solution polymerization process for producing polyethylene compositions. Furthermore, the invention relates to, but is not limited to, rotational molded articles, particularly large and thick rotational molded parts, such as those for large tanks. [Background technology]

[0002] Rotational molding, also known as rotomolding, is used to manufacture hollow plastic products. This process is often described in four steps: (1) introducing the polymer (often in the form of a solid powder), (2) slow, twin-axis rotation of the mold combined with heating of the powder to form a uniform molten mass, (3) cooling and solidification of the molten mass, and (4) removing the plastic part from the mold. Twin-axis rotation of the mold is essential in steps (2) and (3) of this process.

[0003] In rotational molding processes, the material is exposed to high temperatures for a relatively long period of time, allowing for the deposition of molten material and complete densification of powder particles. The solidification of the molten material proceeds gradually and unevenly across the entire thickness of the molded product. In resin design, it is necessary to consider the ability of the material to rapidly sinter and densify, exhibit good thermal stability, and show optimal crystallization behavior in terms of mechanical properties and dimensional stability (see Rao et al., Polymer Engineering and Science,

[1972] , Vol. 12, No. 4, pp. 237-264).

[0004] The mold is subjected to relatively low rotational speeds (typically in the range of 4–30 rpm). In this process, the plastic powder gradually melts, starting from the layer adjacent to the mold surface and progressing toward the inner free surface that will become the hollow plastic part. Once the layer of particles adheres to the mold surface and a melt transition occurs, surface energy causes an aggregation process (sintering). During the powder deposition process, air bubbles are trapped between the particles, eventually forming bubbles. These bubbles slowly disappear due to gas dissolution in the molten material. To ensure the formation of a bubble-free molded product, it is crucial to minimize the size of the bubbles initially formed during powder densification. This is achieved by ensuring rapid aggregation between individual particles. Aggregation is promoted by surface energy, but the aggregation rate is slower for resins with high viscosity and relative modulus. In this conversion process, the deformation rate of the polymer is very slow. Therefore, the most important rheological properties are low shear viscosity (zero shear viscosity), the temperature dependence of viscosity, especially in the temperature range near the melt transition, and the relative modulus of the material.

[0005] Rheological parameters related to rotational molding are described in the following literature, for example: (a) Bellehumeur et al., Polymer Engineering and Science (1996), Vol. 36, No. 17, pp. 2198-2207; (b) Bellehumeur et al., Rheologica Acta (1998), Vol. 37, pp. 270-278; (c) Wang et al., Polymer Engineering and Science (2004), Vol. 44, No. 9, pp. 1662-1669.

[0006] The evaluation of the relative modulus is based on measurements performed at low frequencies that are best suited to the conditions related to powder sintering and densification in rotational molding. The relative modulus can be evaluated from DMA frequency sweep measurements performed at 190°C, based on the ratio of G' to G'' at a frequency of 0.05 rad / s. Data reported in the literature indicate that resin compositions with high relative modulus tend to be difficult to process in terms of slow powder densification. Wang et al. reported suitable rotational moldability for a blended composition characterized by a high relative modulus of 0.125 (2004). In that study, the effect of plastomer content on the rotational moldability of polypropylene was investigated. Further analysis of the results published by Wang et al. showed that the relative modulus increases with higher plastomer content (G' / G'' > 0.13), and correspondingly, it becomes more difficult to achieve complete densification during rotational molding evaluation.

[0007] When developing thermoplastic resins suitable for use in the preparation of molded products such as rotational molded articles, key considerations include resistance to environmental stress over time (e.g., environmental stress crack resistance [ESCR]), impact resistance (e.g., Izod impact test performance), and processability (rheology suitable for rotational molding applications).

[0008] While several polyethylene resins suitable for use in molded parts have been developed, further improvements are still needed, particularly in resins used in the manufacture of large and / or thick rotationally molded parts, such as those for large tanks.

[0009] For example, U.S. Patent No. 7022770 discloses the ESCR performance of polyethylene compositions suitable for molded articles, but does not teach how to achieve a balance between ESCR performance and processability.

[0010] On the other hand, U.S. Patent No. 10808053 teaches that an inverse comonomer distribution is preferred for molding applications and discloses examples including long-chain branching. However, these examples have a density of 0.930 g / cm³. 3It is limited to compositions of less than [amount missing], and its performance has only been confirmed in film applications.

[0011] U.S. Patent No. 8,076,421 discloses compositions based on molecular fractions with very low molecular weight (GPC-RI) and very high molecular weight (GPC-LC), but these examples are also limited to film applications.

[0012] U.S. Patent No. 8101687 describes a multimodal ethylene copolymer, identifying one of its low molecular weight components as a heterogeneous ethylene interpolymer. These compositions exhibit good stress crack resistance and are suitable for use in pipes. However, there is an upper limit of 1.0 g / 10 min for the melt flow index.

[0013] Resins with a low melt flow index (less than 1.5 g / 10 min) are also described in U.S. Patent No. 9,169,337, specifically a bimodal composition with improved ESCR for blow molding applications. These compositions have relatively high molecular weights and a relatively broad molecular weight distribution.

[0014] Furthermore, U.S. Patent No. 8,492,498 discloses compositions having a high ESCR, but is limited to those with a primary structure parameter (PSP2) greater than 8.9.

[0015] There is still a need for a novel polyethylene resin that can be used in rotational molding applications and simultaneously exhibits good rigidity, toughness, and environmental resistance while maintaining good processability.

[0016] This invention was devised in light of the above considerations. [Overview of the Initiative]

[0017] A first aspect of the present invention is a polyethylene composition, (i) 0.880~0.930 g / cm³ 3 Density, molecular weight distribution of 1.7~2.7 (M w / Mn ), and 10 to 60 weight percent of a first ethylene copolymer having a weight average molecular weight (M w ) of 140,000 to 250,000 g / mol, and (ii) a density of 0.940 to 0.975 g / cm 3 , a molecular weight distribution (M w / M n ) of 2.0 to 3.3, and 90 to 40 weight percent of a second ethylene copolymer having a weight average molecular weight (M w ) of 20,000 to 90,000 g / mol, and comprising, the ratio (SCB1 / SCB2) of the number of short chain branches per 1000 carbon atoms in the first ethylene copolymer to the number of short chain branches per 1000 carbon atoms in the second ethylene copolymer is at least 5.0, the polyethylene composition has a density of at least 0.940 g / cm 3 , a melt index (I2) of less than 3.0 g / 10 min, a melt flow ratio (I 21 / I2) of at most 60, and a long chain branching coefficient (LCBF) of at most 0.0400, where the weight percent of the first or second ethylene copolymer is defined as the weight of the first or second ethylene copolymer divided by the total weight of the first ethylene copolymer and the second ethylene copolymer and multiplied by 100%, a polyethylene composition.

[0018] The present invention relates to a polyethylene composition having a density of at least 0.940 g / cm 3This invention provides a polyethylene composition having a density of 1.0 to 3.0 g / 10 min, or a melt index of less than 3.0 g / 10 min, suitable for molding applications (especially rotational molding), and possessing high toughness and ESCR properties. This composition is advantageous for the manufacture of large and / or thick rotational molded parts, such as those for large tanks, because it offers an exceptional combination of performance (toughness, stiffness, ESCR) and processability (rheology). This composition has a high comonomer content and an inverse comonomer distribution. This composition also contains a limited amount of long-chain branching, resulting in high zero-shear viscosity and high flow resistance at low deformation rates. This is advantageous in preventing excessive flow during the manufacture of large and / or thick rotational molded parts, particularly because the heating cycles of such parts can be long, thus increasing the risk of the resin reaching its excessive melt flow limit.

[0019] A second aspect of the present invention is a solution polymerization process for producing a polyethylene composition, wherein the polymerization process is: A step of polymerizing ethylene and alpha-olefin using a metallocene catalyst in a first reactor, The process involves polymerizing ethylene and alpha-olefin using a Ziegler-Natta catalyst in a second reactor. Includes, The first reactor and the second reactor are configured in series with each other. Polyethylene composition, (i) 0.880~0.930 g / cm³ 3 Density, molecular weight distribution of 1.7~2.7 (M w / M n ), and weight-average molecular weight (M) of 140,000 to 250,000 g / mol w A first ethylene copolymer having 10 to 60 weight percent, (ii) 0.940~0.975 g / cm³ 3 Density, molecular weight distribution (M) of 2.0-3.3 w / M n ), and weight-average molecular weight (M) of 20,000 to 90,000 g / mol w) containing 90-40 weight percent of a second ethylene copolymer and Includes, The ratio of the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer to the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer (SCB1 / SCB2) is at least 5.0. The polyethylene composition contains at least 0.940 g / cm³ 3 Density, melt index (I2) of less than 3.0g / 10min, and melt flow ratio (I2) of up to 60. 21 / I2), and having a long-chain branching coefficient (LCBF) of up to 0.0400, The weight percentage of the first or second ethylene copolymer is defined as the weight of the first or second ethylene copolymer divided by the total weight of the first and second ethylene copolymers, multiplied by 100%, in a solution polymerization process.

[0020] Therefore, the second embodiment provides a solution polymerization process for producing the polyethylene composition of the first embodiment.

[0021] Preferably, the process of the second embodiment is a double reactor process.

[0022] A third aspect of the present invention is a rotationally molded article prepared from a polyethylene composition, Polyethylene composition, (i) 0.880~0.930 g / cm³ 3 Density, molecular weight distribution of 1.7~2.7 (M w / M n ), and weight-average molecular weight (M) of 140,000 to 250,000 g / mol w A first ethylene copolymer having 10 to 60 weight percent, (ii) 0.940~0.975 g / cm³ 3 Density, molecular weight distribution (M) of 2.0-3.3 w / M n ), and weight-average molecular weight (M) of 20,000 to 90,000 g / mol w) containing 90-40 weight percent of a second ethylene copolymer and Includes, The ratio of the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer to the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer (SCB1 / SCB2) is at least 5.0. The polyethylene composition contains at least 0.940 g / cm³ 3 Density, melt index (I2) of less than 3.0g / 10min, and melt flow ratio (I2) of up to 60. 21 / I2), and having a long-chain branching coefficient (LCBF) of up to 0.0400, The weight percentage of the first or second ethylene copolymer is defined as the weight of the first or second ethylene copolymer divided by the total weight of the first and second ethylene copolymers, multiplied by 100%, in a rotationally molded article.

[0023] Therefore, the third embodiment provides a rotationally molded article prepared from the polyethylene composition of the first embodiment.

[0024] The present invention includes combinations of the described embodiments and preferred features, unless such combinations are clearly unacceptable or explicitly avoided.

[0025] Embodiments and experiments illustrating the principle of the present invention will be described below with reference to the attached drawings. [Brief explanation of the drawing]

[0026] [Figure 1] Figure 1 shows the temperature rise elution fractionation profiles obtained from TREF-CEF for Invention Examples 1-3 and Comparative Examples 7, 12, and 13. [Figure 2] Figure 2 shows the molecular weight distribution and comonomer distribution from GPC-FTIR measurements (Examples 1-3 and Comparative Examples 15 and 16 are shown in Graph A, while Example 3, Comparative Examples 7 and 10-13 are shown in Graph B). [Figure 3]Figure 3 shows the complex viscosity profiles obtained from DMA frequency sweeps at 190°C for the inventive example and several comparative examples (Graphs A, B, and C), and the relationship between the Ellis model estimated zero shear viscosity and the weight-average molecular weight (Graph D). [Figure 4] Figure 4 shows the ESCR results under condition A100 (Graph A) and the Izod impact (Graph B), plotted against the bending secant modulus. [Figure 5] Figure 5 shows the results of tests performed on rotationally molded specimens, specifically the mean ARM impact fracture energy at -40°C (Graphs A and B), ductility at -40°C (Graphs C and D), and the difference between the density and plaque density after rotational molding (as-is) (Graphs E and F). [Modes for carrying out the invention]

[0027] Aspects and embodiments of the present invention will be described with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art. All documents referenced herein are incorporated herein by reference.

[0028] <Definition of Terms> Unless otherwise indicated, all figures or expressions relating to the quantities of ingredients, preparation conditions, etc., used herein and in the claims should be understood in all cases as being modified by the term “approximately.” Therefore, unless otherwise indicated, the numerical parameters described in the following specification and the appended claims are approximations that may vary depending on the desired characteristics that different embodiments wish to achieve. Each numerical parameter should be interpreted, at least by applying ordinary rounding techniques, taking into account the reported significant figures, not as an attempt to limit the application of the doctrine of equivalents to the claims. The figures described in the specific examples are reported as accurately as possible. However, each figure inherently contains a certain degree of error that inevitably arises from the standard deviation found in the respective test measurements.

[0029] It should be understood that any numerical range described herein is intended to include all subranges contained therein. For example, the range "1 to 10" is intended to include all subranges between the stated minimum value of 1 and the stated maximum value of 10, i.e., the minimum value is 1 or greater and the maximum value is 10 or less. Since the disclosed numerical ranges are continuous, they include all values ​​between the minimum and maximum values. Unless otherwise specified, the various numerical ranges specified in this application are approximations.

[0030] All compositional ranges expressed herein are in practice limited to a total of 100 percent (volume or weight) and not exceeding 100 percent. Where multiple components may be present in a composition, the sum of the maximum amounts of each component may exceed 100 percent, assuming, as is readily apparent to those skilled in the art, that the amounts of components actually used conform to a maximum of 100 percent.

[0031] To form a more complete understanding of this disclosure, the following terms are defined and should be used throughout the accompanying drawings and descriptions of the various embodiments.

[0032] As used herein, the term “monomer” refers to a small molecule that can react chemically and chemically bond with itself or other monomers to form polymers.

[0033] As used herein, the terms "α-olefin" or "alpha-olefin" are used to describe monomers having a linear hydrocarbon chain containing 3 to 20 carbon atoms with a double bond at one end of the chain, and the equivalent term is "linear α-olefin".

[0034] As used herein, the terms “polyethylene” or “ethylene polymer” refer to a polymer produced from ethylene monomer and optionally one or more additional monomers, regardless of the specific catalyst or process used to produce the ethylene polymer.

[0035] The terms "ethylene homopolymer" or "polyethylene homopolymer" mean a product of a polymerization process in which ethylene alone was intentionally added or intentionally present as a polymerizable monomer.

[0036] The terms "ethylene copolymer" or "polyethylene copolymer" mean a product of a polymerization process in which ethylene and one or more α-olefins were intentionally added or intentionally present as polymerizable monomers.

[0037] So-called "long chain branches" or "long chain branching" are macromolecular in nature and are distinguished from short chain branches because, for example, they can be as long as the polymer backbone (to which the long chain branches are attached).

[0038] As used herein, the term “unsubstituted” means that a hydrogen radical is bonded to the molecular group following the term “unsubstituted.” The term “substituted” means that the group following the term has one or more moieties (non-hydrogen radicals) that replace one or more hydrogen radicals at any position within the group. Non-exclusive examples of moieties include halogen radicals (F, Cl, Br), hydroxyl groups, carbonyl groups, carboxyl groups, silyl groups, amine groups, phosphine groups, alkoxy groups, phenyl groups, naphthyl groups, C1-C 30 Alkyl alkyl groups, C2-C 30This includes alkenyl groups and combinations thereof. Non-limiting examples of substituted alkyl and aryl include acyl radicals, alkylsilyl radicals, alkylamino radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals, dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl radicals, alkyl- and dialkyl-carbamoyl radicals, acyloxy radicals, acylamino radicals, arylamino radicals, and combinations thereof.

[0039] As used herein, the terms “hydrocarbyl,” “hydrocarbyl radical,” or “hydrocarbyl group” refer to linear or cyclic aliphatic, olefin, acetylene, and aryl (aromatic) radicals comprising hydrogen and one hydrogen-deficient carbon.

[0040] As used herein, “alkyl radical” includes linear, branched, and cyclic paraffinic radicals lacking one hydrogen radical, and non-limiting examples include methyl (-CH3) and ethyl (-CH2CH3) radicals. The term “alkenyl radical” refers to linear, branched, and cyclic hydrocarbons containing at least one carbon-carbon double bond lacking one hydrogen radical.

[0041] As used herein, the term “aryl” group includes phenyl, naphthyl, pyridyl, and other radicals whose molecules have an aromatic ring structure, with non-limiting examples including naphthylene, phenanthrene, and anthracene. An “arylalkyl” group is an alkyl group having an aryl group pendanted therefrom, with non-limiting examples including benzyl, phenethyl, and tolylmethyl. An “alkylaryl” group is an aryl group having one or more alkyl groups pendanted therefrom, with non-limiting examples including tolyl, xylyl, mesityl, and cumyl.

[0042] As used herein, the term “heteroatom” includes any atom other than carbon and hydrogen that can bond to carbon. A “heteroatom-containing group” is a hydrocarbon radical that contains a heteroatom and may contain one or more identical or different heteroatoms. In some embodiments, a heteroatom-containing group is a hydrocarbyl group containing one to three atoms selected from the group consisting of boron, aluminum, silicon, germanium, nitrogen, phosphorus, oxygen, and sulfur. Non-limiting examples of heteroatom-containing groups include radicals such as imines, amines, oxides, phosphines, ethers, ketones, oxoazoline heterocyclic compounds, oxazolines, and thioethers. The term “heterocyclic” refers to a cyclic system having a carbon skeleton containing one to three atoms selected from the group consisting of boron, aluminum, silicon, germanium, nitrogen, phosphorus, oxygen, and sulfur.

[0043] This disclosure provides a polyethylene composition comprising two components: (i) a first ethylene copolymer, and (ii) a second ethylene copolymer different from the first ethylene copolymer.

[0044] In some embodiments, polyethylene compositions are useful for manufacturing molded articles.

[0045] In some embodiments, polyethylene compositions are useful for the manufacture of rotationally molded articles.

[0046] In some embodiments, polyethylene compositions are useful in the manufacture of compression molded articles or injection molded articles.

[0047] In some embodiments, polyethylene compositions are useful for the production of inflation films.

[0048] <First ethylene copolymer> In some embodiments, the first ethylene copolymer comprises both polymerized ethylene and at least one polymerized α-olefin comonomer, with polymerized ethylene making up the majority.

[0049] In some embodiments, the α-olefin that can copolymerize with ethylene to produce a first ethylene copolymer may be selected from the group comprising 1-propene, 1-butene, 1-pentene, 1-hexene, and 1-octene, as well as mixtures thereof.

[0050] In some embodiments, the first ethylene copolymer is prepared using a single-site catalyst, non-limiting examples of which include phosphine imine catalysts, metallocene catalysts, and constrained geometric catalysts, all of which are well known in the art.

[0051] In some embodiments, the first ethylene copolymer is prepared using a single-site polymerization catalyst in a solution-phase polymerization process.

[0052] In some embodiments, the first ethylene copolymer is prepared using a single-site catalyst having hafnium (Hf) as the active metal center.

[0053] In some embodiments, the first ethylene copolymer is an ethylene / 1-octene copolymer.

[0054] In some embodiments, the first ethylene copolymer is prepared using a metallocene catalyst.

[0055] In some embodiments, the first ethylene copolymer is prepared using a crosslinked metallocene catalyst.

[0056] In some embodiments, the first ethylene copolymer is prepared using a crosslinked metallocene catalyst having formula (I): [ka]

[0057] In formula (I), M is a group 4 metal selected from titanium, zirconium, or hafnium; G is a group 14 element selected from carbon, silicon, germanium, tin, or lead; R1 is a hydrogen atom, C 1-20 Hydrocarbyl radical, C 1-20 Alkyl radicals, or C 6-10 It is an aryl oxide radical; R2 and R3 are hydrogen atoms, C 1-20 Hydrocarbyl radical, C 1-20 Alkyl radical or C 6-10 Independently selected from aryl oxide radicals; R4 and R5 are hydrogen atoms, unsubstituted C 1-20 Hydrocarbyl radical, substituted C 1-20 Hydrocarbyl radical, C 1-20 Alkyl radical or C 6-10 It is independently selected from the aryl oxide radical; Q is independently an activatable leaving ligand.

[0058] In some embodiments, G is carbon.

[0059] In some embodiments, R4 and R5 are independently aryl groups. In some embodiments, R4 and R5 are independently a phenyl group or a substituted phenyl group. In some embodiments, R4 and R5 are phenyl groups. In some embodiments, R4 and R5 are independently substituted phenyl groups. In some embodiments, R4 and R5 are substituted phenyl groups, and the phenyl groups are substituted with substituted silyl groups. In some embodiments, R4 and R5 are substituted phenyl groups, where the phenyl groups are substituted with trialkylsilyl groups. In some embodiments, R4 and R5 are substituted phenyl groups, where the phenyl groups are substituted with a trialkylsilyl group at the para position. In one embodiment, R4 and R5 are substituted phenyl groups, where the phenyl groups are substituted with a trimethylsilyl group at the para position. In another embodiment, R4 and R5 are substituted phenyl groups, where the phenyl groups are substituted with a triethylsilyl group at the para position. In some embodiments, R4 and R5 are independently alkyl groups. In some embodiments, R4 and R5 are independently alkenyl groups.

[0060] In some embodiments, R1 is hydrogen. In some embodiments, R1 is an alkyl group. In some embodiments, R1 is an aryl group. In some embodiments, R1 is an alkenyl group.

[0061] In some embodiments, R2 and R3 are independently hydrocarbyl groups having 1 to 30 carbon atoms. In some embodiments, R2 and R3 are independently aryl groups. In some embodiments, R2 and R3 are independently alkyl groups. In some embodiments, R2 and R3 are independently alkyl groups having 1 to 20 carbon atoms. In some embodiments, R2 and R3 are independently a phenyl group or a substituted phenyl group. In some embodiments, R2 and R3 are tert-butyl groups. In some embodiments, R2 and R3 are hydrogen.

[0062] In some embodiments, M is hafnium (Hf).

[0063] In some embodiments, the first ethylene copolymer is prepared using a crosslinked metallocene catalyst having formula (I): [ka]

[0064] In formula (I), G is a Group 14 element selected from carbon, silicon, germanium, tin, or lead; R1 is a hydrogen atom, C 1-20 Hydrocarbyl radical, C 1-20 Alkyl radicals, or C 6-10 It is an aryl oxide radical; R2 and R3 are hydrogen atoms, C 1-20 Hydrocarbyl radical, C 1-20 Alkyl radical or C 6-10 Independently selected from aryl oxide radicals; R4 and R5 are hydrogen atoms, unsubstituted C 1-20 Hydrocarbyl radical, substituted C 1-20 Hydrocarbyl radical, C 1-20 Alkyl radical or C 6-10 It is independently selected from the aryl oxide radical; Q is independently an activatable leaving ligand.

[0065] In this disclosure, the term “activatable” means that ligand Q can be cleaved from a metal center M via a protonolysis reaction, or abstracted from a metal center M by a suitable acidic or electrophilic catalytic compound (also known as a “cocatalytic” compound), examples of which are described below. Activatable ligand Q can also be converted to another ligand that is cleaved or abstracted from a metal center M (for example, a halide can be converted to an alkyl group). While we do not wish to be bound by a single theory, protonolysis or abstraction reactions generate an active “cationic” metal center capable of polymerizing olefins.

[0066] In some embodiments, the activatable ligand Q is independently selected from the group consisting of: hydrogen atoms; halogen atoms; C 1~20 Hydrocarbyl radical, C 1~20 Alkoxy radicals, and C 6-10Aryl or aryloxy radical, where each of the hydrocarbyl, alkoxy, aryl, or aryloxy radicals may be unsubstituted or further substituted with one or more halogens or other groups; C 1-8 Alkyl; C 1-8 Alkoxy; C 6-10 Q is an aryl or aryloxy; an amide or phosphide radical, but Q is not a cyclopentadienyl. Alternatively, two Q ligands may bond to each other to form, for example, a substituted or unsubstituted diene ligand (e.g., 1,3-butadiene); or a delocalized heteroatom-containing group such as an acetate or acetamidinate group. In a convenient embodiment of this disclosure, each Q is a halide atom, C 1~4 The ligand Q is independently selected from the group consisting of alkyl radicals and benzyl radicals. Particularly suitable activatable ligands Q are monoanionic, such as halides (e.g., chlorides) or hydrocarbyls (e.g., methyl, benzyl).

[0067] In some embodiments, the single-site catalyst used to produce the first ethylene copolymer is diphenylmethylene(cyclopentadienyl)(2,7-di-t-butylfluorenyl)hafnium dichloride having the following molecular formula: [(2,7-tBu2Flu)Ph2C(Cp)HfCl2].

[0068] In some embodiments, the single-site catalyst used to produce the first ethylene copolymer is diphenylmethylene(cyclopentadienyl)(2,7-di-t-butylfluorenyl)hafniumdimethyl, which has the following molecular formula: [(2,7-tBu2Flu)Ph2C(Cp))HfMe2].

[0069] In addition to the single-site catalyst molecule itself, the active single-site catalyst system may further include one or more of the following: an alkylaluminoxane cocatalyst and an ionic activator. The single-site catalyst system may also optionally include a hindered phenol.

[0070] Although the precise structure of alkylaluminoxanes is unknown, experts in the field generally agree that they are oligomeric species containing repeating units of the following general formula: (R)2AlO-(Al(R)-O) n -Al(R)2 (wherein the formula, the R group may be the same or different linear, branched, or cyclic hydrocarbyl radicals containing 1 to 20 carbon atoms, and n is 0 to about 50). A non-limiting example of alkylaluminoxane is methylaluminoxane (or MAO), where each R group is a methyl radical.

[0071] In some embodiments, R of the alkylaluminoxane is a methyl radical, and m is 10 to 40.

[0072] In some embodiments, the co-catalyst is modified methylaluminoxane (MMAO).

[0073] It is well known in the art that alkylaluminoxanes can play a dual role as both alkylating and activating agents. Therefore, alkylaluminoxane cocatalysts are often used in combination with activatable ligands such as halogens.

[0074] Generally, ionic surfactants consist of a cation and a bulky anion, the latter being substantially non-coordinating. A non-limiting example of an ionic surfactant is a four-coordinating boron ionic surfactant, which has four ligands bonded to the boron atom. Several formulas are shown below as non-limiting examples of boron ionic surfactants: [R 5 ] + [B(R 7 )4] - (In the formula, B represents a boron atom, and R 5 is an aromatic hydrocarbyl (e.g., triphenylmethyl cation), and each R 7This is independently selected from the following: a phenyl radical substituted with 3 to 5 substituents selected from unsubstituted or fluorine atoms, or a C substituted with unsubstituted or fluorine atoms. 1~4 Alkyl or alkoxy radicals, and formula -Si(R 9 )3 silyl radicals, where each R 9 is a hydrogen atom and C 1-4 (Selected independently of alkyl radicals), and [(R 8 ) t ZH] + [B(R 7 )4] - (In the formula, B is a boron atom, H is a hydrogen atom, Z is a nitrogen or phosphorus atom, t is 2 or 3, R 8 C 1~8 alkyl radicals, unsubstituted or up to 3 C 1-4 Selected from phenyl radicals substituted with alkyl radicals, or one R 8 R may form an anilinium radical together with the nitrogen atom, 7 (This is defined above).

[0075] In both equations, R 7A non-limiting example is the pentafluorophenyl radical. In general, boron ionic surfactants can be described as salts of tetra(perfluorophenyl)boron, and non-limiting examples include anilinium, carbonium, oxonium, phosphonium, and sulfonium salts of tetra(perfluorophenyl)boron with anilinium and trityl (or triphenylmethylium). Non-limiting examples of additional ionic surfactants include triethylammonium tetra(phenyl)boron, tripropylammonium tetra(phenyl)boron, tri(n-butyl)ammonium tetra(phenyl)boron, trimethylammonium tetra(p-tolyl)boron, trimethylammonium tetra(o-tolyl)boron, tributylammonium tetra(pentafluorophenyl)boron, tripropylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(m,m-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, tri(n-butyl)ammonium tetra(o-tolyl)boron, N,N-dimethylanilinium tetra(phenyl)boron, N,N-diethylanilinium tetra(phenyl)boron, and N,N-diethylanilinium N,N-2,4,6-Pentamethylanilinium tetra(phenyl)boron, di-(isopropyl)ammonium tetra(pentafluorophenyl)boron, dicyclohexylammonium tetra(phenyl)boron, triphenylphosphonium tetra(phenyl)boron, tri(methylphenyl)phosphonium tetra(phenyl)boron, tri(dimethylphenyl)phosphonium tetra(phenyl)boron, tropylium tetrakisspentafluorophenyl borate, triphenylmethylium tetrakisspentafluorophenyl borate, benzene(diazonium) tetrakisspentafluorophenyl borate, tropylium tetrakis(2,3,5,6-tetrafluorophenyl) borate, triphenylmethylium tetrakis(2,3,5,6-tetrafluorophenyl) borate, benzene(diazonium) tetrakis(3,4,Examples include 5-trifluorophenyl) borate, tropylium tetrakis(3,4,5-trifluorophenyl) borate, benzene(diazonium) tetrakis(3,4,5-trifluorophenyl) borate, tropylium tetrakis(1,2,2-trifluoroethenyl) borate, triphenylmethylium tetrakis(1,2,2-trifluoroethenyl) borate, benzene(diazonium) tetrakis(1,2,2-trifluoroethenyl) borate, tropylium tetrakis(2,3,4,5-tetrafluorophenyl) borate, triphenylmethylium tetrakis(2,3,4,5-tetrafluorophenyl) borate, and benzene(diazonium) tetrakis(2,3,4,5-tetrafluorophenyl) borate. Easily available commercial ionic surfactants include N,N-dimethylanilinium tetrakispentafluorophenyl borate and triphenylmethylium tetrakispentafluorophenyl borate.

[0076] Non-limiting examples of hindered phenols include butylated phenol antioxidants, butylated hydroxytoluene, 2,6-di-tert-butyl-4-ethylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and octadecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate.

[0077] To generate an active metallocene-based catalytic system, the amounts and molar ratios of three or four components—a metallocene single-site catalyst, an alkylaluminoxane, an ionic activator, and an optional hindered phenol—are optimized.

[0078] In some embodiments, the single-site catalyst used to produce the first ethylene copolymer generates long-chain branching, and the first ethylene copolymer contains long-chain branching (hereinafter referred to as "LCB").

[0079] Long chain branching (LCB) is a well-known structural phenomenon in ethylene copolymers and is well known to those skilled in the art. Conventionally, there are three methods for LCB analysis: nuclear magnetic resonance (NMR) spectroscopy (see, e.g., J. C Randall, J. Macromol. Sci., Rev., Macromol. Chem. Phys., 1989, Vol. 29, p. 201); triple-detection SEC with DRI, viscometer, and low-angle laser light scattering detector (see, e.g., W. W. Yau and D. Hill, Int. J. Polym. Anal. Character., 1996, Vol. 2, p. 151); and rheology (see, e.g., W. W. Graessley, Acc. Chem. Res., 1977, Vol. 10, pp. 332-339). In embodiments of this disclosure, the long chain branching is essentially macromolecule, i.e., long enough to be observed in NMR spectra, triple-detector SEC experiments, or rheological experiments.

[0080] In some embodiments, the first ethylene copolymer includes long-chain branching characterized by the long-chain branching coefficient LCBF disclosed herein. In embodiments of the disclosure, the upper limit of the LCBF of the first ethylene copolymer may be 0.5000, or 0.4000, or 0.0375, or 0.3000 (dimensionless). In embodiments of the disclosure, the lower limit of the LCBF of the first ethylene copolymer may be 0.0010, or 0.0015, or 0.0020, or 0.0050, or 0.0070, or 0.0100, or 0.0500, or 0.1000 (dimensionless).

[0081] In embodiments of the present disclosure, the LCBF of the first ethylene copolymer is at least 0.0010, or at least 0.0020, or at least 0.0050, or at least 0.0070, or at least 0.0100.

[0082] The first ethylene copolymer may contain catalyst residues that reflect the chemical composition of the catalyst formulation used to produce it. Those skilled in the art will understand that catalyst residues are typically quantified by parts per million of metal in the first ethylene copolymer (or polyethylene composition; see below), where the metals present are derived from the metals in the catalyst formulation used to produce it. Non-limiting examples of metal residues that may be present include Group IV metals, titanium, zirconium, and hafnium. In embodiments of the present disclosure, the upper limit of the ppm of metal in the first ethylene copolymer may be about 3.0 ppm, in other cases about 2.0 ppm, and in yet other cases about 1.5 ppm. In embodiments of the present disclosure, the lower limit of the ppm of metal in the first ethylene copolymer may be about 0.03 ppm, in other cases about 0.09 ppm, and in yet other cases about 0.15 ppm.

[0083] In some embodiments, the first ethylene copolymer contains 0.03 to 3.0 ppm of metal, or 0.09 to 3.0 ppm of metal, or 0.15 to 3.0 ppm of metal, or 0.03 to 2.0 ppm of metal, or 0.09 to 2.0 ppm of metal, or 0.15 to 2.0 ppm of metal, or 0.03 to 1.5 ppm of metal, or 0.09 to 1.5 ppm of metal, or 0.15 to 1.5 ppm of metal.

[0084] In some embodiments, the first ethylene copolymer has at least 1, or at least 2, or at least 3, or at least 4, or at least 5, or at least 7, or at least 8.5, or at least 10 short-chain branches (SCB1) per 1000 carbon atoms.

[0085] In some embodiments, the first ethylene copolymer has up to 100, or up to 75, or up to 50, or up to 30, or up to 25, or up to 20 short-chain branches (SCB1) per 1000 carbon atoms.

[0086] In some embodiments, the first ethylene copolymer has 1 to 100 short-chain branches (SCB1) per 1000 carbon atoms. In some embodiments, the first ethylene copolymer has 2 to 100 short-chain branches (SCB1) per 1000 carbon atoms, or 3 to 100 short-chain branches (SCB1) per 1000 carbon atoms, or 4 to 100 short-chain branches (SCB1) per 1000 carbon atoms, or 2 to 75 short-chain branches (SCB1) per 1000 carbon atoms, or 3 to 75 short-chain branches (SCB1) per 1000 carbon atoms, or 4 to 75 short-chain branches (SCB1) per 1000 carbon atoms, or per 1000 carbon atoms 2 to 50 short chain branches (SCB1), or 3 to 50 short chain branches (SCB1) per 1000 carbon atoms, or 4 to 50 short chain branches (SCB1) per 1000 carbon atoms, or 2 to 30 short chain branches (SCB1) per 1000 carbon atoms, or 3 to 30 short chain branches (SCB1) per 1000 carbon atoms, or 4 to 30 short chain branches (SCB1) per 1000 carbon atoms, or 5 to 30 short chain branches (SCB1) per 1000 carbon atoms, or 7 to 30 short chains per 1000 carbon atoms Branching (SCB1), or short-chain branching (SCB1) with 2 to 25 carbon atoms per 1000 carbon atoms, or short-chain branching (SCB1) with 3 to 25 carbon atoms per 1000 carbon atoms, or short-chain branching (SCB1) with 4 to 25 carbon atoms per 1000 carbon atoms, or short-chain branching (SCB1) with 5 to 25 carbon atoms per 1000 carbon atoms, or short-chain branching (SCB1) with 7 to 25 carbon atoms per 1000 carbon atoms, or short-chain branching (SCB1) with 8.5 to 25 carbon atoms per 1000 carbon atoms, or short-chain branching (SCB1) with 10 to 25 carbon atoms per 1000 carbon atoms ), or having 2 to 20 short-chain branches (SCB1) per 1000 carbon atoms, or 3 to 20 short-chain branches (SCB1) per 1000 carbon atoms, or 4 to 20 short-chain branches (SCB1) per 1000 carbon atoms, or 5 to 20 short-chain branches (SCB1) per 1000 carbon atoms, or 7 to 20 short-chain branches (SCB1) per 1000 carbon atoms, or 8.5 to 20 short-chain branches (SCB1) per 1000 carbon atoms, or 10 to 20 short-chain branches (SCB1) per 1000 carbon atoms.

[0087] In some embodiments, the first ethylene copolymer has 2 to 30 short-chain branches per 1000 carbon atoms.

[0088] In some embodiments, the first ethylene copolymer has 4 to 25 short-chain branches per 1000 carbon atoms.

[0089] In some embodiments, the first ethylene copolymer has 4 to 20 short-chain branches per 1000 carbon atoms.

[0090] Short-chain branching (i.e., short-chain branching per 1000 carbon atoms in the backbone, SCB1) is branching caused by the presence of α-olefin comonomers in ethylene copolymers. For example, 1-butene comonomers have 2 carbon atoms, 1-hexene comonomers have 4 carbon atoms, and 1-octene comonomers have 6 carbon atoms.

[0091] In embodiments of this disclosure, the number of short-chain branches per 1,000 carbon atoms in the first ethylene copolymer (SCB1) is greater than the number of short-chain branches per 1,000 carbon atoms in the second ethylene copolymer (SCB2).

[0092] In some embodiments, the density of the first copolymer is lower than the density of the second ethylene copolymer.

[0093] The first ethylene copolymer is 0.880-0.930 g / cm³ 3 It has a density of 0.880 to 0.925 g / cm³, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the first ethylene copolymer has a density of 0.880 to 0.925 g / cm³. 3 , or 0.880~0.922 g / cm³ 3 , or 0.880~0.920 g / cm³ 3 , or 0.880~0.918 g / cm³ 3 , or 0.890~0.930 g / cm³ 3, or 0.890 - 0.925 g / cm 3 , or 0.890 - 0.922 g / cm 3 , or 0.890 - 0.920 g / cm 3 , or 0.890 - 0.918 g / cm 3 , or 0.900 - 0.930 g / cm 3 , or 0.900 - 0.925 g / cm 3 , or 0.900 - 0.922 g / cm 3 , or 0.900 - 0.920 g / cm 3 , or 0.900 - 0.918 g / cm 3 , or 0.905 - 0.930 g / cm 3 , or 0.905 - 0.925 g / cm 3 , or 0.905 - 0.922 g / cm 3 , or 0.905 - 0.920 g / cm 3 , or 0.905 - 0.918 g / cm 3 , or 0.910 - 0.930 g / cm 3 , or 0.910 - 0.925 g / cm 3 , or 0.910 - 0.922 g / cm 3 , or 0.910 - 0.920 g / cm 3 , or 0.910 - 0.918 g / cm 3 has a density of

[0094] In some embodiments, the first ethylene copolymer has a density of 0.880 - 0.925 g / cm 3 less than

[0095] In some embodiments, the first ethylene copolymer has a density of 0.890 - 0.925 g / cm 3

[0096] In some embodiments, the first ethylene copolymer has a density less than 0.920 g / cm 3 , or less than 0.918 g / cm 3

[0097] In some embodiments, the first ethylene copolymer has a density of 0.900 g / cm​3 If it exceeds 0.905 g / cm³, or if it is 0.905 g / cm³ 3 It has a density exceeding that.

[0098] In some embodiments, the melt index (I2) of the first ethylene copolymer is smaller than the melt index (I2) of the second ethylene copolymer.

[0099] In some embodiments, the first ethylene copolymer has a melt index (I2) of 10 g / 10 min or less, or 5.0 g / 10 min or less, or 2.5 g / 10 min or less, or 1.0 g / 10 min or less, or 0.7 g / 10 min or less, or 0.5 g / 10 min or less, or less than 0.5 g / 10 min.

[0100] In some embodiments, the first ethylene copolymer has a melt index (I2) of up to 1.0 g / 10 min.

[0101] In some embodiments, the first ethylene copolymer has a melt index (I2) of 0.001 to 10.0 g / 10 min, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the melt index (I2) of the first ethylene copolymer is 0.001 to 7.5 g / 10 min, or 0.001 to 5.0 g / 10 min, or 0.001 to 2.5 g / 10 min, or 0.001 to 1.0 g / 10 min, or 0.001 to 0.7 g / 10 min, or 0.001 to 0.5 g / 10 min, or 0.01 to 10.0 g / 10 min, or 0.01 to 7.5 g / 10 min, or 0.01 to 5.0 g / 10 min, or 0. It may be 0.1-2.5g / 10 min, or 0.01-1.0g / 10 min, or 0.01-0.7g / 10 min, or 0.01-0.5g / 10 min, or 0.05-10.0g / 10 min, or 0.05-7.5g / 10 min, or 0.05-5.0g / 10 min, or 0.05-2.5g / 10 min, or 0.05-1.0g / 10 min, or 0.05-0.7g / 10 min, or 0.05-0.5g / 10 min, or less than 0.05-0.5g / 10 min.

[0102] In some embodiments, the first ethylene copolymer has a melt index (I2) of 0.001 to 0.7 g / 10 min.

[0103] In some embodiments, the first ethylene copolymer has a melt flow ratio (I) less than 25, or less than 23, or less than 20. 21 It has / I2).

[0104] The first ethylene copolymer has a weight-average molecular weight (M) of 130,000 to 275,000 g / mol. w ) has any narrow range within this range and any value included within these ranges. For example, in some embodiments, the first ethylene copolymer has a weight-average molecular weight (M) of 130,000 to 260,000 g / mol, or 130,000 to 250,000 g / mol, or 130,000 to 240,000 g / mol, or 140,000 to 260,000 g / mol, or 140,000 to 250,000 g / mol, or 140,000 to 240,000 g / mol. w ) has.

[0105] In some embodiments, the first ethylene copolymer has a weight-average molecular weight (M) of at least 125,000 g / mol, or at least 130,000 g / mol, or at least 135,000 g / mol, or at least 140,000 g / mol, or at least 145,000 g / mol. w ) has.

[0106] In some embodiments, the first ethylene copolymer has a weight-average molecular weight (M) of up to 275,000 g / mol, or up to 265,000 g / mol, or up to 260,000 g / mol, or up to 255,000 g / mol, or up to 250,000 g / mol, or up to 245,000 g / mol, or up to 240,000 g / mol. w ) has.

[0107] In some embodiments, the molecular weight distribution (M) of the first ethylene copolymer w / Mn The upper limit of (M) is about 2.7, or about 2.5, or about 2.4, or about 2.3. In some embodiments, the molecular weight distribution (M) of the first ethylene copolymer is w / M n The lower limit of ) is approximately 1.7, or approximately 1.8, or approximately 1.9.

[0108] The first ethylene copolymer has a molecular weight distribution of 1.7 to 2.7 M w / M n It has a molecular weight distribution (M) of 1.8-2.7, or 1.8-2.5, or 1.8-2.4, or 1.8-2.3, or 1.9-2.7, or 1.9-2.5, or 1.9-2.4, or 1.9-2.3. w / M n ) has.

[0109] In some embodiments, the CDBI of the first ethylene copolymer 50 The upper limit may be about 98% by weight, in other cases about 95 wt%, and in yet other cases about 90 wt%. In some embodiments, the CDBI of the first ethylene copolymer 50 The lower limit may be about 70% by weight, or in other cases about 75% by weight, or in yet other cases about 80% by weight.

[0110] In some embodiments, during solution-phase polymerization in a single reactor, at least 65% by weight, or at least 70% by weight, or at least 75% by weight, or at least 80% by weight, or at least 85% by weight of CDBI 50 A single-site catalyst that yields an ethylene copolymer having [a specific characteristic] is used in the preparation of the first ethylene copolymer.

[0111] In some embodiments, the first ethylene copolymer is more than about 60% by weight, or more than about 65% by weight, or more than about 70% by weight, or more than about 75% by weight, or more than about 80% by weight, or more than about 85% by weight of CDBI 50 It is an ethylene copolymer having [a certain characteristic].

[0112] The weight percentage (wt%) of the first ethylene copolymer in the polyethylene composition (i.e., the weight percentage of the first ethylene copolymer based on the total weight of the first and second ethylene copolymers) is between 10 wt% and 60 wt%, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the weight percentage (wt%) of the first ethylene copolymer in the polyethylene copolymer composition is about 10 wt% to about 55 wt%, or about 10 wt% to about 50 wt%, or about 10 wt% to about 45 wt%, or about 10 wt% to about 40 wt%, or about 15 wt% to about 55 wt%, or about 15 wt% to about 50 wt%, or about 15 wt% to about 40 wt%, or about 15 wt% to about 35 wt%, or about 20 wt% to about 45 wt%, or about 20 wt% to about 40 wt%, or about 20 wt% to about 35 wt%, or about 25 wt% to about 50 wt%, or about 25 wt% to about 40 wt%, or about 25 wt% to about 35 wt%.

[0113] <Second Ethylene Copolymer> In some embodiments, the second ethylene copolymer is prepared using a multi-site catalyst system, non-limiting examples of which include Ziegler-Natta catalysts and chromium catalysts, both of which are well known in the art.

[0114] In some embodiments, the alpha-olefins that can copolymerize with ethylene to produce a second ethylene copolymer are selected from the group comprising 1-propene, 1-butene, 1-pentene, 1-hexene, and 1-octene, as well as mixtures thereof.

[0115] In some embodiments, the second ethylene copolymer is a heterogeneously branched ethylene copolymer.

[0116] In some embodiments, the second ethylene copolymer is an ethylene / 1-octene copolymer.

[0117] In some embodiments, the second ethylene copolymer is prepared using a Ziegler-Natta catalyst system.

[0118] The Ziegler-Natta catalyst system is well known to those skilled in the art. The Ziegler-Natta catalyst may be an in-line Ziegler-Natta catalyst system or a batch Ziegler-Natta catalyst system. The term "in-line Ziegler-Natta catalyst system" refers to the continuous synthesis of a small amount of activated Ziegler-Natta catalyst system and the immediate injection of this catalyst into at least one continuous-operating reactor, where the catalyst polymerizes ethylene with one or more optionally selected α-olefins to form an ethylene polymer. The terms "batch Ziegler-Natta catalyst system" or "batch Ziegler-Natta pro-catalyst" refer to the synthesis of a much larger amount of catalyst or pro-catalyst in one or more mixing vessels, either outside or separated from a continuously operating solution polymerization process. The prepared batch catalyst Ziegler-Natta catalyst system, or batch Ziegler-Natta pro-catalyst, is transferred to a catalyst storage tank. The term "procatalyst" refers to an inert catalyst system (inert with respect to ethylene polymerization), which is converted into an active catalyst by the addition of an alkylaluminum cocatalyst. If necessary, the procatalyst is pumped from a storage tank to at least one continuous-operation reactor, where the active catalyst polymerizes ethylene and one or more optionally selected α-olefins to form an ethylene copolymer. The procatalyst may be converted into an active catalyst in the reactor, outside the reactor, or en route to the reactor.

[0119] A wide variety of compounds can be used to synthesize an activated Ziegler-Natta catalyst system. The following describes various compounds that can be combined to produce an activated Ziegler-Natta catalyst system. Those skilled in the art will understand that the embodiments described herein are not limited to the specific compounds disclosed.

[0120] The activated Ziegler-Natta catalyst system can be formed from magnesium compounds, chloride compounds, metal compounds, alkylaluminum co-catalysts, and aluminum alkyls. As will be understood by those skilled in the art, the Ziegler-Natta catalyst system may also contain additional components, non-limiting examples of which are electron donors, such as amines or ethers.

[0121] Non-limiting examples of active in-line (or batch) Ziegler-Natta catalyst systems can be prepared as follows: In the first step, a solution of a magnesium compound is reacted with a solution of a chloride compound to form a magnesium chloride support suspended in solution. Non-limiting examples of magnesium compounds include Mg(R) 1 )2 is given, and in the formula, R 1 The groups may be the same or different, and may be linear, branched, or cyclic hydrocarbyl radicals containing 1 to 10 carbon atoms. Non-limiting examples of chloride compounds include R 2 Cl is mentioned, and in the formula, R 2 represents a linear, branched, or cyclic hydrocarbyl radical containing a hydrogen atom or 1 to 10 carbon atoms. In the first step, the solution of the magnesium compound may contain an aluminum alkyl group. Non-limiting examples of aluminum alkyl groups include Al(R 3 )3 is given, and in the formula, R 3 The groups may be the same or different, and may be linear, branched, or cyclic hydrocarbyl radicals containing 1 to 10 carbon atoms. In the second step, a solution of the metal compound is added to a solution of magnesium chloride to support the metal compound on the magnesium chloride. A non-limiting example of a suitable metal compound is M(X) n or MO(X)n Examples include the following formulas, where M represents a metal selected from groups 4-8 of the periodic table, or a mixture of metals selected from groups 4-8; O represents oxygen; X represents a chloride or bromide; and n is an integer from 3 to 6 that satisfies the oxidation state of the metal. Additional non-limiting examples of suitable metal compounds include group 4-8 metal alkyls, metal alkoxides (which can be prepared by reacting a metal alkyl with an alcohol), and mixed ligand metal compounds including halides, alkyl and alkoxide ligands. In the third step, a solution of the alkylaluminum cocatalyst is added to the metal compound supported on magnesium chloride. A wide variety of alkylaluminum cocatalysts are suitable, as shown in the following formula: Al(R 4 ) p (OR 9 ) q (X) r (In the formula, R 4 The groups may be the same or different, and may be hydrocarbyl groups having 1 to 10 carbon atoms, OR 9 The groups may be the same or different, and may be an alkoxy group or an aryloxy group, R 9 X is a hydrocarbyl group having 1 to 10 carbon atoms bonded to oxygen, where X is a chloride or bromide, and (p+q+r)=3, where p is greater than 0. Non-limiting examples of commonly used alkylaluminum cocatalysts include trimethylaluminum, triethylaluminum, tributylaluminum, dimethylaluminum methoxide, diethylaluminum ethoxide, dibutylaluminum butoxide, dimethylaluminum chloride or bromide, diethylaluminum chloride or bromide, dibutylaluminum chloride or bromide, and ethylaluminum dichloride or dibromide.

[0122] The process described in the above paragraph for synthesizing an active in-line (or batch) Ziegler-Natta catalyst system can be carried out in a variety of solvents, and non-limiting examples of solvents include linear or branched C5-C12 Examples include alkanes or mixtures thereof.

[0123] In some embodiments, the short-chain branching in the second ethylene copolymer can be such that the number of short-chain branches per 1000 carbon atoms (SCB2 / 1000C) is approximately 0.05 to approximately 10.0. In some embodiments, the short-chain branching in the second ethylene copolymer can be such that the number of branches per 1000 carbon atoms (SCB2 / 1000C) is approximately 0.05 to 7.5, or 0.05 to 5.0, or 0.05 to 3.0, or 0.05 to 1.5, or 0.05 to 1.0, or 0.08 to 7.5, or 0.08 to 5.0, or 0.08 to 3.0, or 0.08 to 1.5, or 0.08 to 1.0.

[0124] In some embodiments, the second ethylene copolymer has 0.05 to 3 short-chain branches (SCB2 / 1000C) per 1000 carbon atoms.

[0125] Short-chain branching (i.e., short-chain branching per 1000 carbon atoms in the backbone, SCB2) is branching caused by the presence of α-olefin comonomers in ethylene copolymers. For example, 1-butene comonomers have 2 carbon atoms, 1-hexene comonomers have 4 carbon atoms, and 1-octene comonomers have 6 carbon atoms.

[0126] In embodiments of this disclosure, the number of short-chain branches per thousand carbon atoms (SCB2) of the second ethylene copolymer is less than the number of short-chain branches per thousand carbon atoms (SCB1) of the first ethylene copolymer.

[0127] In some embodiments, the density of the second copolymer is greater than the density of the first ethylene copolymer.

[0128] The second ethylene copolymer is 0.940-0.975 g / cm³. 3It has a density of 0.940 to 0.970 g / cm³, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the second ethylene copolymer has a density of 0.940 to 0.970 g / cm³. 3 , or 0.940~0.965 g / cm³ 3 , or 0.945~0.975 g / cm³ 3 , or 0.945~0.970 g / cm³ 3 , or 0.945~0.965 g / cm³ 3 , or 0.950~0.975 g / cm³ 3 , or 0.950~0.970 g / cm³ 3 , or 0.950~0.965 g / cm³ 3 , or 0.955~0.975 g / cm³ 3 , or 0.955~0.972 g / cm³ 3 , or 0.955~0.970 g / cm³ 3 , or 0.955~0.967 g / cm³ 3 , or 0.955~0.965 g / cm³ 3 It has a density of .

[0129] In some embodiments, the melt index (I2) of the second ethylene copolymer is greater than the melt index (I2) of the first ethylene copolymer.

[0130] In some embodiments, the second ethylene copolymer has a melt index (I2) of at least 2.0 g / 10 min.

[0131] In some embodiments, the second ethylene copolymer has a melt index (I2) of 2.0 to 500 g / 10 min, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the melt index (I2) of the second ethylene copolymer is 2 to 250 g / 10 min, or 2 to 100 g / 10 min, or 2 to 75 g / 10 min, or 2 to 50 g / 10 min, or 2 to 40 g / 10 min, or 2 to 30 g / 10 min, or 2 to 25 g / 10 min, or 2 to 20 g / 10 min, or 5 to 250 g / 10 min, or 5 to 100 g / 10 min, or 5 to 75 g / 10 minutes, or 5-50g / 10 minutes, or 5-40g / 10 minutes, or 5-30g / 10 minutes, or 5-25g / 10 minutes, or 5-20g / 10 minutes, or 10-250g / 10 minutes, or 10-100g / 10 minutes, or 10-75g / 10 minutes, or 10-50g / 10 minutes, or 10-40g / 10 minutes, or 10-30g / 10 minutes, or 10-25g / 10 minutes, or 10-20g / 10 minutes.

[0132] In some embodiments, the second ethylene copolymer has a melt index (I2) of 2.0 to 50 g / 10 min.

[0133] The second ethylene copolymer has a weight-average molecular weight (M) of 20,000 to 90,000 g / mol. w ) has any narrow range within this range and any value included within these ranges. For example, in some embodiments, the second ethylene copolymer has a weight-average molecular weight (M) of 20,000 to 80,000 g / mol, or 20,000 to 70,000 g / mol, or 20,000 to 65,000 g / mol, or 30,000 to 90,000 g / mol, or 30,000 to 80,000 g / mol, or 30,000 to 70,000 g / mol, or 30,000 to 65,000 g / mol, or 40,000 to 90,000 g / mol, or 40,000 to 80,000 g / mol, or 40,000 to 70,000 g / mol, or 40,000 to 65,000 g / mol. w ) has.

[0134] In some embodiments, the second ethylene copolymer has a weight-average molecular weight (M) of at least 20,000 g / mol, or at least 30,000 g / mol, or at least 40,000 g / mol. w ) has.

[0135] In some embodiments, the second ethylene copolymer has a weight-average molecular weight (M) of up to 90,000 g / mol, or up to 80,000 g / mol, or up to 70,000 g / mol, or up to 65,000 g / mol. w ) has.

[0136] The weight-average molecular weight (M) of the second ethylene copolymer w ) is the weight-average molecular weight (M) of the first ethylene copolymer. w It is lower than ).

[0137] In some embodiments, the molecular weight distribution of the second ethylene copolymer (M w / M n The upper limit of (M) is approximately 4.0, or approximately 3.5, or approximately 3.3, or approximately 3.1, or approximately 2.9, or approximately 2.8, or approximately 2.7. In some embodiments, the molecular weight distribution (M) of the second ethylene copolymer is w / M n The lower limit of ) is approximately 2.0, or approximately 2.2, or approximately 2.4, or approximately 2.5.

[0138] In this embodiment, the second ethylene copolymer has a molecular weight distribution of 2.0 to 4.5 (M w / M n) has a molecular weight distribution (M) of 2.0-4.0, or 2.0-3.5, or 2.0-3.1, or 2.0-2.9, or 2.0-2.8, or 2.0-2.7, or 2.2-3.3, or 2.2-3.1, or 2.2-2.9, or 2.2-2.8, or 2.2-2.7, or 2.4-3.3, or 2.4-3.1, or 2.4-2.9, or 2.4-2.8, or 2.4-2.7, or 2.5-3.3, or 2.5-3.1, or 2.5-2.9, or 2.5-2.8, or 2.5-2.7 w / M n ) n It has.

[0139] In some embodiments, less than 60% by weight or less than 50 wt% of CDBI is added during solution phase polymerization in a single reactor. 50 A multi-site catalyst that yields an ethylene copolymer having [a specific characteristic] is used to prepare a second ethylene copolymer.

[0140] The weight percentage (wt%) of the second ethylene copolymer in the polyethylene composition (i.e., the weight percentage of the second ethylene copolymer based on the total weight of the first and second ethylene copolymers) may be between 90 wt% and 40 wt%, and includes any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the weight percentage (wt%) of the second ethylene copolymer in the polyethylene copolymer composition is about 90 wt% to about 45 wt%, or about 90 wt% to about 50 wt%, or about 90 wt% to about 55 wt%, or about 90 wt% to about 60 wt%, or about 85 wt% to about 45 wt%, or about 85 wt% to about 50 wt%, or about 85 wt% to about 60 wt%, or about 85 wt% to about 65 wt%, or about 80 wt% to about 55 wt%, or about 80 wt% to about 60 wt%, or about 80 wt% to about 65 wt%, or about 75 wt% to about 50 wt%, or about 75 wt% to about 60 wt%, or about 75 wt% to about 65 wt%.

[0141] <Polyethylene Composition> The polyethylene composition comprises a first ethylene copolymer and a second ethylene copolymer, respectively as defined above.

[0142] The polyethylene compositions disclosed herein can be made using any well-known techniques in the art, including, but not limited to, melt blending, solution blending, or in-reactor blending to combine the first ethylene copolymer and the second ethylene copolymer.

[0143] In some embodiments, the polyethylene composition of the present disclosure is made by producing a first ethylene copolymer using a single-site catalyst in a first reactor and a second ethylene copolymer using a multi-site catalyst in a second reactor.

[0144] In some embodiments, the polyethylene composition of the present disclosure is made by forming a first ethylene copolymer by polymerizing ethylene and an α-olefin using a single-site catalyst in a first reactor; and forming a second ethylene copolymer by polymerizing ethylene and an α-olefin using a multi-site catalyst in a second reactor.

[0145] In some embodiments, the polyethylene composition of the present disclosure is made by forming a first ethylene copolymer by polymerizing ethylene and an α-olefin using a single-site catalyst in a first solution-phase polymerization reactor; and forming a second ethylene copolymer by polymerizing ethylene and an α-olefin using a multi-site catalyst in a second solution-phase polymerization reactor.

[0146] In some embodiments, the polyethylene composition of the present disclosure is prepared by polymerizing ethylene and an α-olefin using a single-site catalyst in a first solution-phase polymerization reactor to form a first ethylene copolymer; and polymerizing ethylene and an α-olefin using a multi-site catalyst in a second solution-phase polymerization reactor to form a second ethylene copolymer; wherein the first and second solution-phase polymerization reactors are configured in series with each other.

[0147] In some embodiments, the polyethylene composition of the present disclosure is prepared by polymerizing ethylene and an α-olefin using a single-site catalyst in a first solution-phase polymerization reactor to form a first ethylene copolymer; and polymerizing ethylene and an α-olefin using a multi-site catalyst in a second solution-phase polymerization reactor to form a second ethylene copolymer; wherein the first and second solution-phase polymerization reactors are configured in parallel with each other.

[0148] In some embodiments, the solution-phase polymerization reactor used as the first solution-phase reactor is a continuous stirred tank reactor or a tubular reactor.

[0149] In some embodiments, the solution-phase polymerization reactor used as the second solution-phase reactor is a continuous stirred tank reactor or a tubular reactor.

[0150] In solution polymerization, the monomers are dissolved / dispersed in a solvent before being fed to the reactor (or in the case of gaseous monomers, the monomers may be fed to the reactor and dissolved in the reaction mixture). Before mixing, the solvent and monomers are generally purified to remove potential catalyst poisons such as water, oxygen, and metal impurities. The purification of the feedstock follows standard practices in the art. For example, molecular sieves, alumina beds, and oxygen removal catalysts are used for monomer purification. The solvent itself (e.g., methylpentane, cyclohexane, hexane or toluene) is preferably treated in the same way.

[0151] The raw materials may be heated or cooled before being supplied to the reactor.

[0152] Generally, catalyst components may be pre-mixed in the reaction solvent or supplied to the reactor as separate streams. In some cases, it may be desirable to pre-mix the catalyst components before they enter the polymerization reaction zone to ensure sufficient reaction time. Such "in-line mixing" techniques are well known to those skilled in the art.

[0153] Solution polymerization processes for the polymerization or copolymerization of ethylene are well known in the art (see, for example, U.S. Patents 6,372,864 and 6,777,509). These processes are carried out in the presence of an inert hydrocarbon solvent. In solution-phase polymerization reactors, a variety of solvents can be used as process solvents, and non-limiting examples include linear, branched, or cyclic C5-C5 polymers. 12 Alkanes are an example. Suitable catalytic solvents include aliphatic and aromatic hydrocarbons. Non-limiting examples of aliphatic catalytic solvents include linear, branched, or cyclic C5-C5 12 Aliphatic hydrocarbons include, for example, pentane, methylpentane, hexane, heptane, octane, cyclohexane, cyclopentane, methylcyclohexane, naphtha hydrogenates, or combinations thereof. Non-limiting examples of aromatic catalyst solvents include benzene, toluene (methylbenzene), ethylbenzene, o-xylene (1,2-dimethylbenzene), m-xylene (1,3-dimethylbenzene), p-xylene (1,4-dimethylbenzene), mixtures of xylene isomers, hemeritene (1,2,3-trimethylbenzene), pseudocumene (1,2,4-trimethylbenzene), mesitylene (1,3,5-trimethylbenzene), mixtures of trimethylbenzene isomers, prehenytene (1,2,3,4-tetramethylbenzene), durene (1,2,3,5-tetramethylbenzene), mixtures of tetramethylbenzene isomers, pentamethylbenzene, hexamethylbenzene, and combinations thereof.

[0154] The polymerization temperature in a conventional solution process may be about 80°C to about 300°C. In some embodiments, the polymerization temperature in a solution process is about 120°C to about 250°C. The polymerization pressure in a solution process may be a “medium-pressure process,” meaning that the pressure in the reactor is less than about 6,000 psi (about 42,000 kilopascals or kPa). In some embodiments, the polymerization pressure in a solution process may be about 10,000 to about 40,000 kPa, or about 14,000 to about 22,000 kPa (i.e., about 2,000 psi to about 3,000 psi).

[0155] Suitable comonomers (i.e., α-olefins) for copolymerization with ethylene in solution-phase polymerization processes include C 3-20 This includes monoolefins and diolefins. In some embodiments, the comonomers that can be copolymerized with ethylene are unsubstituted or contain up to two C atoms. 1-6 C substituted with alkyl radicals 3-12 α-olefin, unsubstituted or C 1-4 C is substituted with up to two substituents selected from the group consisting of alkyl radicals. 8-12 Vinyl aromatic monomers, unsubstituted or C 1-4 C substituted with alkyl radicals 4-12 This includes linear or cyclic diolefins. In further embodiments, the α-olefins copolymerizable with ethylene are one or more propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene, styrene, alpha-methylstyrene, and restricted cyclic olefins, such as cyclobutene, cyclopentene, dicyclopentadiene, norbornene, alkyl-substituted norbornene, alkenyl-substituted norbornene (e.g., 5-methylene-2-norbornene and 5-ethylidene-2-norbornene, bicyclo-(2,2,1)-hepta-2,5-diene).

[0156] In some embodiments, the polyethylene composition comprises ethylene and one or more alpha-olefins selected from the group consisting of 1-butene, 1-hexene, 1-octene, and mixtures thereof.

[0157] In some embodiments, the polyethylene composition comprises ethylene and one or more alpha-olefins selected from the group including 1-hexene, 1-octene, and mixtures thereof.

[0158] In some embodiments, the polyethylene composition comprises ethylene and 1-octene.

[0159] In some embodiments, the polyethylene composition has one or more α-olefins in 0.1 to 7.5 mole percent, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition has one or more α-olefins in 0.1 to 5.0 mole percent, or one or more α-olefins in 0.1 to 3.0 mole percent, or one or more α-olefins in 0.5 to 5.0 mole percent, or one or more α-olefins in 0.5 to 3 mole percent, or one or more α-olefins in 0.1 to 2.5 mole percent, or one or more α-olefins in 0.1 to 2.0 mole percent, or one or more α-olefins in 0.5 to 2.0 mole percent.

[0160] In some embodiments, the polyethylene composition contains 0.1 to 5.0 mol percent of 1-octene, or 0.1 to 3.0 mol percent of 1-octene, or 0.5 to 5.0 mol% of 1-octene, or 0.5 to 3 mol% of 1-octene, or 0.1 to 2.5 mol% of 1-octene, or 0.1 to 2.0 mol% of 1-octene, or 0.5 to 2.0 mol% of 1-octene.

[0161] A polyethylene composition comprising a first ethylene copolymer and a second ethylene copolymer (as defined above) has a ratio (SCB1 / SCB2) of at least 5.0 (i.e., SCB1 / SCB2 ≥ 5.0) between the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer (i.e., SCB1) and the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer (i.e., SCB2). In some embodiments, the ratio of short-chain branches (SCB1) in the first ethylene copolymer to short-chain branches (SCB2) in the second ethylene copolymer is at least 7.5 or greater than 7.5. In some embodiments, the ratio of short-chain branches (SCB1) in the first ethylene copolymer to short-chain branches (SCB2) in the second ethylene copolymer is at least 10.0 or greater than 10.0. In some embodiments, the ratio of short-chain branches (SCB1) in the first ethylene copolymer to short-chain branches (SCB2) in the second ethylene copolymer is at least 12.5 or greater than 12.5. In some embodiments, the ratio of short-chain branches (SCB1) in the first ethylene copolymer to short-chain branches (SCB2) in the second ethylene copolymer is at least 15.0 or greater than 15.0.

[0162] In some embodiments, the ratio (SCB1 / SCB2) of the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer to the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer is at least 10.

[0163] In some embodiments, a polyethylene composition comprising a first ethylene copolymer and a second ethylene copolymer (as defined above) has a ratio (SCB1 / SCB2) of the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer (i.e., SCB1) to the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer (i.e., SCB2) of 5.0 to 100, or 5.0 to 80.0, or 10.0 to 100.0, or 10.0 to 80.0.

[0164] In some embodiments, the polyethylene composition is characterized by the short-chain branching frequency at Mz (SCB-Mz), the short-chain branching frequency at Mw (SCB-Mw), and the short-chain branching frequency at Mn (SCB-Mn), where the short-chain branching frequency is the number of short-chain branches per 1000 polymer backbone carbon atoms at Mz, Mw, and Mn, respectively, in GPC-FTIR analysis.

[0165] In some embodiments, the polyethylene composition has a short-chain branching content that satisfies the following condition: SCB-Mz > SCB-Mw > SCB-Mn.

[0166] In some embodiments, the polyethylene composition has an SCB-Mz with more than 2.0 short-chain branches per 1000 polymer backbone carbon atoms. In some embodiments, the polyethylene composition has an SCB-Mz with 2.0 to 7.5 short-chain branches per 1000 polymer backbone carbon atoms.

[0167] In some embodiments, the polyethylene composition has an SCB-Mw with 0.5 to 5.0 short-chain branches per 1000 polymer backbone carbon atoms. In some embodiments, the polyethylene composition has an SCB-Mw with 0.5 to 3.5 short-chain branches per 1000 polymer backbone carbon atoms.

[0168] In some embodiments, the polyethylene composition has an SCB-Mn with less than 2.0 short-chain branches per 1000 polymer backbone carbon atoms, or less than 1.0 short-chain branches per 1000 polymer backbone carbon atoms.

[0169] In some embodiments, the polyethylene composition is 0.940 g / cm 3 or more, or exceeds 0.940 g / cm 3 or is 0.942 g / cm 3 or more, or exceeds 0.942 g / cm 3 or is 0.944 g / cm 3 or more, or exceeds 0.944 g / cm 3 or is 0.945 g / cm 3Above, or 0.945 g / cm³ 3 If it exceeds 0.946 g / cm³, or if it is 0.946 g / cm³ 3 Above, or 0.946 g / cm³ 3 If it exceeds 0.947 g / cm³, or 0.947 g / cm³ 3 Above, or 0.947 g / cm³ 3 It has a density exceeding that.

[0170] In some embodiments, the polyethylene composition is 0.942 g / cm³. 3 It has a density exceeding 0.947 g / cm³. In some embodiments, the polyethylene composition is 0.947 g / cm³. 3 It has a density exceeding that.

[0171] In some embodiments, the polyethylene composition is 0.940 to 0.965 g / cm³. 3 It has a density of 0.940 to 0.960 g / cm³, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition has a density of 0.940 to 0.960 g / cm³. 3 , or 0.940~0.957 g / cm³ 3 , or 0.940~0.955 g / cm³ 3 , or 0.940~0.953 g / cm³ 3 , or 0.940~0.950 g / cm³ 3 , or 0.942~0.960 g / cm³ 3 , or 0.942~0.957 g / cm³ 3 , or 0.942~0.955 g / cm³ 3 , or 0.942~0.953 g / cm³ 3 , or 0.942~0.950 g / cm³ 3 , or 0.944~0.960 g / cm³ 3 , or 0.944~0.957 g / cm³ 3 , or 0.944~0.955 g / cm³ 3 , or 0.944~0.953 g / cm³ 3 , or 0.944~0.950 g / cm³ 3 , or 0.945~0.960 g / cm³ 3 , or 0.945~0.957 g / cm³ 3, or 0.945~0.955 g / cm³ 3 , or 0.945~0.953 g / cm³ 3 , or 0.945~0.950 g / cm³ 3 , or 0.946~0.960 g / cm³ 3 , or 0.946~0.957 g / cm³ 3 , or 0.946~0.955 g / cm³ 3 , or 0.946~0.953 g / cm³ 3 , or 0.946~0.950 g / cm³ 3 , or 0.947~0.960 g / cm³ 3 , or 0.947~0.957 g / cm³ 3 , or 0.947~0.955 g / cm³ 3 , or 0.947~0.953 g / cm³ 3 , or 0.947~0.950 g / cm³ 3 It has a density of .

[0172] In some embodiments, the polyethylene composition is 0.942 g / cm³. 3 ~0.957 g / cm³ 3 It has a density of .

[0173] In some embodiments, the polyethylene composition is 0.945 g / cm³ 3 ~0.955 g / cm³ 3 It has a density of .

[0174] In some embodiments, the polyethylene composition is 0.947 g / cm³ 3 ~0.955 g / cm³ 3 It has a density of .

[0175] In some embodiments, the polyethylene composition has a weight-average molecular weight (M) of 130,000 g / mol or less, 120,000 g / mol or less, or 110,000 g / mol or less, or 105,000 g / mol or less, or less than 130,000 g / mol, less than 120,000 g / mol, or less than 110,000 g / mol, or less than 105,000 g / mol. w ) has.

[0176] In some embodiments, the polyethylene composition has a weight-average molecular weight (M) of 30,000 to 150,000 g / mol. w ) has a range including any narrow range within this range and any value contained within these ranges. For example, in some embodiments, the polyethylene composition has a weight-average molecular weight (M) of 50,000 to 150,000 g / mol, or 50,000 to 130,000 g / mol, or 50,000 to 120,000 g / mol, or 70,000 to 150,000 g / mol, or 70,000 to 130,000 g / mol, or 70,000 to 120,000 g / mol, or 70,000 to 110,000 g / mol, or 70,000 to 105,000 g / mol, or 75,000 to 130,000 g / mol, or 75,000 to 120,000 g / mol, or 75,000 to 110,000 g / mol, or 75,000 to 105,000 g / mol. w ) has.

[0177] In some embodiments, the polyethylene composition has a weight-average molecular weight (M) of 70,000 to 120,000 g / mol. w ) has.

[0178] In some embodiments, the polyethylene composition has a number average molecular weight M of 60,000 g / mol or less, or 50,000 g / mol or less, or less than 50,000 g / mol, or 45,000 g / mol or less, or less than 45,000 g / mol, or 40,000 g / mol or less, or less than 40,000 g / mol, or 35,000 g / mol or less, or less than 35,000 g / mol. n It has.

[0179] In some embodiments, the polyethylene composition has a number-average molecular weight (M) of 5,000 to 60,000 g / mol. n) has any narrow range within this range and any value included within these ranges. For example, in some embodiments, the polyethylene composition has a number average molecular weight (M) of 5,000 to 50,000 g / mol, or 10,000 to 50,000 g / mol, or 10,000 to 45,000 g / mol, or 15,000 to 45,000 g / mol, or 20,000 to 45,000 g / mol, or 10,000 to 40,000 g / mol, or 15,000 to 40,000 g / mol, or 20,000 to 40,000 g / mol, or 10,000 to 35,000 g / mol, or 15,000 to 35,000 g / mol, or 20,000 to 35,000 g / mol. n ) has.

[0180] In some embodiments, the polyethylene composition has a number-average molecular weight (M) of 20,000 to 40,000 g / mol. n ) has.

[0181] In some embodiments, the polyethylene composition has a Z-average molecular weight (M) of 400,000 g / mol or less, or 350,000 g / mol or less, or 310,000 g / mol or less, or 275,000 g / mol or less, or 250,000 g / mol or less, or less than 400,000 g / mol, or less than 350,000 g / mol, or less than 310,000 g / mol, or less than 275,000 g / mol, or less than 250,000 g / mol. z ) has.

[0182] In some embodiments, the polyethylene composition has a Z-average molecular weight (M) of less than 400,000 g / mol. z ) has. In some embodiments, the polyethylene composition has a Z average molecular weight (M) of less than 310,000 g / mol. z ) has.

[0183] In some embodiments, the polyethylene composition has a Z-average molecular weight (M) of 100,000 to 400,000 g / mol. z) has any narrow range within this range and any value included within these ranges. For example, in some embodiments, the polyethylene composition is 100,000 to 350,000 g / mol, or 125,000 to 350,000 g / mol, or 150,000 to 350,000 g / mol, or 160,000 to 350,000 g / mol, or 200,000 to 350,000 g / mol, or 100,000 to 310,000 g / mol, or 125,000 to 310,000 g / mol, or 150,000 to 310,000 g / mol, or 160,000 to 310,000 g / mol, or 2 The Z-average molecular weight (M) of molecules with a molecular weight of 00,000 to 310,000 g / mol, or 100,000 to 275,000 g / mol, or 125,000 to 275,000 g / mol, or 150,000 to 275,000 g / mol, or 160,000 to 275,000 g / mol, or 200,000 to 275,000 g / mol, or 100,000 to 250,000 g / mol, or 125,000 to 250,000 g / mol, or 150,000 to 250,000 g / mol, or 160,000 to 250,000 g / mol. z ) has.

[0184] In some embodiments, the polyethylene composition has a Z-average molecular weight (M) of 100,000 to 350,000 g / mol. z ) has.

[0185] In some embodiments, the polyethylene composition has a Z-average molecular weight (M) of 100,000 to 250,000 g / mol. z ) has.

[0186] In some embodiments, the polyethylene composition exhibits a bimodal profile (i.e., a bimodal molecular weight distribution) in gel permeation chromatography (GPC) analysis.

[0187] In some embodiments, the polyethylene copolymer composition has a bimodal profile in a gel permeation chromatograph produced according to the method of ASTM D6474-99.

[0188] In some embodiments, the polyethylene composition exhibits a unimodal profile (i.e., a unimodal molecular weight distribution) in gel permeation chromatography (GPC) analysis.

[0189] In some embodiments, the polyethylene copolymer composition has a unimodal profile in a gel permeation chromatograph produced according to the method of ASTM D6474-99.

[0190] The term "unimodal" is defined herein as meaning that in a GPC curve, there is only one clear and significant peak or maximum. In contrast, the use of the term "bimodal" means that, in addition to the first peak, there is a second peak or shoulder representing a higher or lower molecular weight component (i.e., the molecular weight distribution can be said to have two maximums in the molecular weight distribution curve). Alternatively, the term "bimodal" means that in a molecular weight distribution curve generated according to the method of ASTM D6474-99, there are two maximums. The term "multimodal" means that in a molecular weight distribution curve generated according to the method of ASTM D6474-99, there are two or more, typically more than two, maximums.

[0191] In some embodiments, the polyethylene composition has a molecular weight distribution (M) of 6.0 or less, or less than 6.0, or 5.5 or less, or less than 5.5, or 5.0 or less, or less than 5.0, or 4.5 or less, or less than 4.5, or less than 4.0, or less than 4.0, or 3.5 or less, or less than 3.5, or less than 3.0, or less than 3.0. w / M n ) has. In some embodiments, the polyethylene composition has a molecular weight distribution of 2.0 to 6.5 (M w / M n) has any narrow range within this range and any value included within these ranges. For example, in some embodiments, the polyethylene composition has a molecular weight distribution (M) of 2.0 to 6.0, or 2.0 to 5.5, or 2.0 to 5.0, or 2.0 to 4.5, or 2.0 to 4.0, or 2.0 to 3.5, or 2.3 to 6.0, or 2.3 to 5.5, or 2.3 to 5.0, or 2.3 to 4.5, or 2.3 to 4.0, or 2.3 to 3.5. w / M n ) has.

[0192] In some embodiments, the polyethylene composition has a molecular weight distribution of less than 4.5 (M w / M n ) has. In some embodiments, the polyethylene composition has a molecular weight distribution of 2.0 to 4.0 (M w / M n ) has.

[0193] In some embodiments, the polyethylene composition has a melt index (I2) of up to 3.0 g / 10 min, or up to 2.8 g / 10 min, or up to 2.6 g / 10 min, or up to 2.4 g / 10 min, or up to 2.2 g / 10 min, or up to 2.0 g / 10 min, or up to 1.8 g / 10 min, or less than 3.0 g / 10 min, or less than 2.8 g / 10 min, or less than 2.6 g / 10 min, or less than 2.4 g / 10 min, or less than 2.2 g / 10 min, or less than 2.0 g / 10 min, or less than 1.8 g / 10 min.

[0194] In embodiments, the polyethylene composition has a melt index (I2) of 1.0 to 3.0 g / 10 min, or less than 1.0 to 3.0 g / 10 min, or less than 3.0 g / 10 min, and includes any narrow range within this range and any value included within these ranges. For example, in some embodiments, the polyethylene composition has a melt index (I2) of 1.0 to 2.8 g / 10 min, or 1.0 to 2.6 g / 10 min, or 1.0 to 2.4 g / 10 min, or 1.0 to 2.2 g / 10 min, or 1.0 to 2.0 g / 10 min, or 1.0 to 1.8 g / 10 min, or 1.3 to 3.0 g / 10 min, or 1.3 to 2.8 g / 10 min, or 1.3 to 2.6 g / 10 min, or 1.3 to 2.4 g / It has a melt index (I2) of 10 minutes, or 1.3-2.2 g / 10 minutes, or 1.3-2.0 g / 10 minutes, or 1.3-1.8 g / 10 minutes, or 1.5-3.0 g / 10 minutes, or 1.5-2.8 g / 10 minutes, or 1.5-2.6 g / 10 minutes, or 1.5-2.4 g / 10 minutes, or 1.5-2.2 g / 10 minutes, or 1.5-2.0 g / 10 minutes, or 1.5-1.8 g / 10 minutes.

[0195] In some embodiments, the polyethylene composition has a melt index (I2) of 1.3 to 3.0 g / 10 min.

[0196] In some embodiments, the polyethylene composition has a melt index (I2) of less than 1.3 to 3.0 g / 10 min.

[0197] In some embodiments, the polyethylene composition has a melt index (I2) of 1.5 to 3.0 g / 10 min.

[0198] In some embodiments, the polyethylene composition has a melt index (I2) of less than 1.5 to 3.0 g / 10 min.

[0199] In some embodiments, the polyethylene composition has a melt index (I2) of 1.3 to 2.6 g / 10 min.

[0200] In some embodiments, the polyethylene composition has a high load melt index (I) of at least 20 g / 10 min, or at least 25 g / 10 min, or at least 30 g / 10 min, or at least 35 g / 10 min, or at least 40 g / 10 min, or more than 20 g / 10 min, or at least 25 g / 10 min, or at least 30 g / 10 min, or at least 35 g / 10 min, or at least 40 g / 10 min. 21 ) has.

[0201] In some embodiments, the polyethylene composition has a high-load melt index (I) of at least 30 g / 10 min. 21 ) has.

[0202] In some embodiments, the polyethylene composition has a high-load melt index (I) of 20-150 g / 10 min. 21 ) and include any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition is 20-125 g / 10 min, or 20-100 g / 10 min, or 20-80 g / 10 min, or 20-70 g / 10 min, or 20-60 g / 10 min, or 25-150 g / 10 min, or 25-125 g / 10 min, or 25-100 g / 10 min, or 25-80 g / 10 min, or 25-70 g / 10 min, or 25-60 g / 10 min, or 30-150 g / 10 min, or 30-125 g / 10 min, or 30-100 g / 10 min , or 30-80g / 10 min, or 30-70g / 10 min, or 30-60g / 10 min, or 35-150g / 10 min, or 35-125g / 10 min, or 35-100g / 10 min, or 35-80g / 10 min, or 35-70g / 10 min, or 35-60g / 10 min, or 40-150g / 10 min, or 40-125g / 10 min, or 40-100g / 10 min, or 40-80g / 10 min, or 40-70g / 10 min, or 40-60g / 10 min high load melt index (I 21 ) has.

[0203] In some embodiments, the polyethylene composition has a high-load melt index (I) of 30-100 g / 10 min. 21) has.

[0204] In some embodiments, the polyethylene composition has a melt flow ratio (I) of 60 or less, or less than 60, 50 or less, or less than 50, or 40 or less, or less than 40. 21 In some embodiments, the polyethylene composition has a melt flow ratio (I2) of 15 to 60. 21 The melt flow ratio (I²) is such that it has any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition has a melt flow ratio (I²) of 15-50, or 15-40, or 20-60, or 20-50, or 20-40, or 25-60, or 25-50, or 25-40. 21 It has / I2).

[0205] In some embodiments, the polyethylene composition has a melt flow ratio of 20 to 50 (I 21 It has / I2).

[0206] In some embodiments, polyethylene compositions have a reverse or partially reversed comonomer distribution profile, as measured by GPC-FTIR. If comonomer incorporation decreases with molecular weight, as measured by GPC-FTIR, the distribution is described as "normal." If comonomer incorporation is nearly constant with respect to molecular weight, as measured by GPC-FTIR, the comonomer distribution is described as "flat" or "uniform." The terms "reverse comonomer distribution" and "partially reverse comonomer distribution" mean that, in the GPC-FTIR data obtained for the copolymer, there is one or more high molecular weight components with higher comonomer incorporation than one or more low molecular weight components. The term "reverse comonomer distribution" is used herein to mean that, across the molecular weight range of the ethylene copolymer, the comonomer content of various polymer fractions is not substantially uniform, and the high molecular weight fraction has a proportionally higher comonomer content (i.e., if comonomer incorporation increases with molecular weight, the distribution is described as "reverse" or "reversed"). Even if comonomer incorporation increases with increasing molecular weight and then decreases, the comonomer distribution is considered "inverted," but may be described as "partially inverted." A partially inverted comonomer distribution shows a peak or maximum value.

[0207] In some embodiments, the polyethylene composition has an inverted comonomer distribution profile, as measured using GPC-FTIR.

[0208] In some embodiments, the polyethylene composition has a partially inverted comonomer distribution profile, as measured using GPC-FTIR.

[0209] In some embodiments, the polyethylene composition contains about 20 to about 75% by weight, or about 20 to about 65% by weight, or about 20 to about 60% by weight of CDBI. 50 It has.

[0210] In some embodiments, the upper limit of parts per million (ppm) of hafnium in the polyethylene composition is about 3.0 ppm, or about 2.5 ppm, or about 2.4 ppm, or about 2.0 ppm, or about 1.5 ppm, or about 1.0 ppm, or about 0.75 ppm, or about 0.5 ppm. In some embodiments, the lower limit of parts per million (ppm) of hafnium in the polyethylene composition is about 0.0015 ppm, or about 0.0050 ppm, or about 0.0075 ppm, or about 0.010 ppm, or about 0.015 ppm, or about 0.030 ppm, or about 0.050 ppm, or about 0.075 ppm, or about 0.100 ppm, or about 0.150 ppm, or about 0.175 ppm, or about 0.200 ppm.

[0211] In some embodiments, the polyethylene composition contains at least 0.0015 ppm of hafnium, or at least 0.005 ppm of hafnium, or at least 0.0075 ppm of hafnium, or at least 0.015 ppm of hafnium, or at least 0.030 ppm of hafnium, or at least 0.050 ppm of hafnium, or at least 0.075 ppm of hafnium, or at least 0.100 ppm of hafnium, or at least 0.125 ppm of hafnium, or at least 0.150 ppm of hafnium, or at least 0.175 ppm of hafnium, or at least 0.200 ppm of hafnium, or at least 0.300 ppm of hafnium, or at least 0.350 ppm of hafnium.

[0212] In some embodiments, the polyethylene composition contains 0.0015 to 2.4 ppm of hafnium, or 0.0050 to 2.4 ppm of hafnium, or 0.0075 to 2.4 ppm of hafnium, or 0.010 to 2.4 ppm of hafnium, or 0.015 to 2.4 ppm of hafnium, or 0.050 to 3.0 ppm of hafnium, or 0.050 to 2.4 ppm of hafnium, or 0.075 to 2.4 ppm of hafnium, or 0.075 to 2.0 ppm of hafnium, or 0.075 to 1.5 ppm of hafnium, or 0.075 to 1.0 ppm of hafnium, or 0.075 to 0 It contains 0.75 ppm of hafnium, or 0.100 to 2.0 ppm of hafnium, or 0.100 to 1.5 ppm of hafnium, or 0.100 to 1.0 ppm of hafnium, or 0.100 to 0.75 ppm of hafnium, or 0.20 to 2.0 ppm of hafnium, or 0.20 to 1.5 ppm of hafnium, or 0.20 to 1.0 ppm of hafnium, or 0.20 to 0.75 ppm of hafnium, or 0.35 to 2.0 ppm of hafnium, or 0.35 to 1.5 ppm of hafnium, or 0.35 to 1.0 ppm of hafnium, or 0.35 to 0.75 ppm of hafnium.

[0213] In some embodiments, the polyethylene composition contains 0.0015 to 2.4 ppm of hafnium.

[0214] In some embodiments, the polyethylene composition includes long-chain branching characterized by a long-chain branching coefficient (LCBF) disclosed herein. In embodiments of this disclosure, the upper limit of the LCBF of the polyethylene composition is 0.0400 (dimensionless).

[0215] In some embodiments, the LCBF of the polyethylene composition is, or at most 0.0375, or at most 0.0370, or at most 0.0350, or at most 0.0330, or at most 0.0300, or at most 0.0270, or at most 0.0250. In some embodiments, the LCBF of the polyethylene composition is less than 0.0400, or less than 0.0370, or less than 0.0350, or less than 0.0330, or less than 0.0300, or less than 0.0270, or less than 0.0250.

[0216] In some embodiments, the LCBF of the polyethylene composition is at least 0.0010, or at least 0.0030, or at least 0.0050, or at least 0.0060, or at least 0.0070, or at least 0.0080. In some embodiments, the LCBF of the polyethylene composition is greater than 0.0010, or greater than 0.0030, or greater than 0.0050, or greater than 0.0060, or greater than 0.0070, or greater than 0.0080.

[0217] In some embodiments, the LCBF of the polyethylene composition is 0.0010 to 0.0400, or 0.0030 to 0.0400, or 0.0050 to 0.0400, or 0.0050 to 0.0375, or 0.0060 to 0.0400, or 0.0070 to 0.0400, or 0.0010 to 0.0370, or 0.0030 to 0.03 70, or 0.0050~0.0370, or 0.0060~0.0370, or 0.0070~0.0370, or 0.0010~0.0350, or 0.0030~0.0350, or 0.0050~0.0350, or 0.0060~0.0350, or 0.0070~0.0350, or 0.0010~0.0330, or 0. 0030~0.0330, or 0.0050~0.0330, or 0.0060~0.0330, or 0.0070~0.0330, or 0.0010~0.0300, or 0.0030~0.0300, or 0.0050~0.0300, or 0.0060~0.0300, or 0.0070~0.0300, or 0.0010~0. The values ​​are 0270, or 0.0030~0.0270, or 0.0050~0.0270, or 0.0060~0.0270, or 0.0070~0.0270, or 0.0010~0.0250, or 0.0030~0.0250, or 0.0050~0.0250, or 0.0060~0.0250, or 0.0070~0.0250.

[0218] In some embodiments, the polyethylene composition has an LCBF of 0.0050 to 0.0375.

[0219] In some embodiments, the polyethylene composition has an LCBF of 0.0050 to 0.0350.

[0220] In some embodiments, the polyethylene composition has an LCBF of 0.0080 to 0.0350.

[0221] In some embodiments, the polyethylene composition has a fraction that elutes at temperatures above 95°C in CTREF analysis.

[0222] In some embodiments, the polyethylene composition has a fraction that elutes at temperatures below 90°C in CTREF analysis.

[0223] In some embodiments, the polyethylene composition has a fraction that elutes at approximately 95°C and a fraction that elutes at 90°C in CTREF analysis.

[0224] In some embodiments, the polyethylene composition has a rheological width parameter (a) measured by the Carreau-Yasuda model that is less than 0.450, or at most 0.450, or less than 0.425, or at most 0.425, or less than 0.400, or at most 0.400, or less than 0.375, or at most 0.375.

[0225] In some embodiments, the polyethylene composition has a rheological width parameter (a) measured by the Carreau-Yasuda model of at least 0.200 or greater than 0.200, or at least 0.225 or greater than 0.225, or at least 0.250 or greater than 0.250.

[0226] In some embodiments, the polyethylene composition has a rheological width parameter (a) measured by the Carreau-Yasuda model of 0.200-0.450, or 0.200-0.425, or 0.200-0.400, or 0.200-0.375, or 0.225-0.450, or 0.225-0.425, or 0.225-0.400, or 0.225-0.375, or 0.250-0.450, or 0.250-0.425, or 0.250-0.400, or 0.250-0.375.

[0227] In some embodiments, the polyethylene composition has a rheological width parameter (a) measured by the Carreau-Yasuda model of less than 0.450. In some embodiments, the polyethylene composition has a rheological width parameter (a) measured by the Carreau-Yasuda model of less than 0.400. In some embodiments, the polyethylene composition has a rheological width parameter (a) measured by the Carreau-Yasuda model of 0.200 to 0.400.

[0228] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 100% IGEPAL® CO-630 under condition A, which is greater than 500 hours, or greater than 600 hours, or greater than 700 hours, or greater than 800 hours, or greater than 900 hours, or greater than 1000 hours, or greater than 1100 hours, or greater than 1200 hours.

[0229] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) of more than 500 hours in 100% IGEPAL CO-630 under condition A, as determined by ASTM D1693. In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) of more than 1000 hours in 100% IGEPAL CO-630 under condition A, as determined by ASTM D1693.

[0230] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 100% IGEPAL CO-630 under condition B, exceeding 500 hours, or exceeding 600 hours, or exceeding 700 hours, or exceeding 800 hours, or exceeding 900 hours, or exceeding 1000 hours, or exceeding 1100 hours, or exceeding 1200 hours.

[0231] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 100% IGEPAL CO-630, under both conditions A and B, of more than 500 hours, or more than 600 hours, or more than 700 hours, or more than 800 hours, or more than 900 hours, or more than 1000 hours, or more than 1100 hours, or more than 1200 hours.

[0232] In some embodiments, a polyethylene composition or a plaque made from a polyethylene composition has an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 100% IGEPAL CO-630 for more than 500 hours, or more than 600 hours, or more than 700 hours, or more than 800 hours, or more than 900 hours, or more than 1000 hours, or more than 1100 hours, or more than 1200 hours, under either condition A or condition B.

[0233] In some embodiments, a polyethylene composition or a plaque made from a polyethylene composition has an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 10% IGEPAL CO-630 under condition A, which is greater than 50 hours, or greater than 60 hours, or greater than 100 hours, or greater than 150 hours, or greater than 200 hours, or greater than 400 hours, or greater than 600 hours, or greater than 700 hours, or greater than 800 hours, or greater than 900 hours.

[0234] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) of more than 50 hours in 10% IGEPAL CO-630 under condition A, as determined by ASTM D1693. In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) of more than 100 hours in 10% IGEPAL CO-630 under condition A, as determined by ASTM D1693.

[0235] In some embodiments, polyethylene compositions or plaques made from polyethylene compositions have an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 10% IGEPAL CO-630 under condition B, exceeding 30 hours, or 40 hours, or 50 hours, or 60 hours, or 100 hours, or 150 hours, or 200 hours, or 400 hours.

[0236] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 10% IGEPAL CO-630 for more than 50 hours, or more than 60 hours, or more than 100 hours, or more than 150 hours, or more than 200 hours, or more than 400 hours, under both conditions A and B.

[0237] In some embodiments, a polyethylene composition or a plaque made from a polyethylene composition has an environmental stress crack resistance (ESCR) determined by ASTM D1693 in 10% IGEPAL CO-630 for more than 50 hours, or more than 60 hours, or more than 100 hours, or more than 150 hours, or more than 200 hours, or more than 400 hours, under either condition A or condition B.

[0238] In some embodiments, the polyethylene composition has a zero shear viscosity (η0) at 190°C of about 4,000 Pa·s to about 20,000 Pa·s, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition has a pressure range of approximately 4,000 Pa·s to approximately 16,000 Pa·s, or approximately 4,000 Pa·s to approximately 14,000 Pa·s, or approximately 4,000 Pa·s to approximately 13,000 Pa·s, or approximately 6,000 Pa·s to approximately 20,000 Pa·s, or approximately 6,000 Pa·s to approximately 16,000 Pa·s, or approximately 6,000 Pa·s to approximately 14,000 Pa·s, or approximately 6,000 Pa·s to approximately 13,000 Pa·s, or approximately 7,000 Pa·s to approximately 20,000 Pa·s, or approximately 7,000 Pa·s to approximately 16,000 Pa·s, or approximately 7,000 Pa·s It has a zero shear viscosity η0 at 190°C of approximately 14,000 Pa·s, or approximately 7,000 Pa·s to approximately 13,000 Pa·s, or approximately 8,000 Pa·s to approximately 20,000 Pa·s, or approximately 8,000 Pa·s to approximately 16,000 Pa·s, or approximately 8,000 Pa·s to approximately 14,000 Pa·s, or approximately 8,000 Pa·s to approximately 13,000 Pa·s, or approximately 10,000 Pa·s to approximately 20,000 Pa·s, or approximately 10,000 Pa·s to approximately 16,000 Pa·s, or approximately 10,000 Pa·s to approximately 14,000 Pa·s, or approximately 10,000 Pa·s to approximately 13,000 Pa·s.

[0239] In some embodiments, the polyethylene composition has a relative modulus (elastic ratio G' / G'') at 0.05 rad / s of up to 0.30, or up to 0.27, or up to 0.25, or up to 0.22, or up to 0.20. In some embodiments, the polyethylene composition has a relative modulus (elastic ratio G' / G'') at 0.05 rad / s of up to 0.25.

[0240] In some embodiments, the polyethylene composition has a melt strength of at least 0.75 cN, or at least 1.00 cN, or at least 1.25 cN, or at least 1.50 cN, or at least 1.75 cN, or at least 2.00 cN, or at least 2.25 cN, or at least 2.50 cN, or at least 2.75 cN.

[0241] In some embodiments, the polyethylene composition has a melt strength of 2.0 to 5.0 cN, or 2.0 to 4.0 cN, or 2.5 to 4.0 cN.

[0242] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a bending secant modulus of 1% of at least 900 MPa or greater than 900 MPa, or at least 950 MPa or greater than 950 MPa, or at least 1000 MPa or greater than 1000 MPa, or at least 1050 MPa or greater than 1050 MPa, or at least 1000 MPa or greater than 1000 MPa.

[0243] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a flexural secant modulus at 1% of 900 to 1400 MPa, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a flexural secant modulus at 900 to 1300 MPa, or 900 to 1200 MPa, or 900 to 1150 MPa, or 950 to 1400 MPa, or 950 to 1300 MPa, or 950 to 1200 MPa, or 950 to 1150 MPa, or 1000 to 1400 MPa, or 1000 to 1300 It has a bending secant modulus of elasticity at 1% of MPa, or 1000-1200 MPa, or 1000-1150 MPa, or 1050-1400 MPa, or 1050-1300 MPa, or 1050-1200 MPa, or 1050-1150 MPa, or 1100-1400 MPa, or 1100-1300 MPa, or 1100-1200 MPa, or 1100-1150 MPa.

[0244] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a bending secant modulus of at least 1000 MPa and 1%. In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a bending secant modulus of at least 1000 to 1300 MPa and 1%.

[0245] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a tensile secant modulus at 1% of at least 900 MPa or greater than 900 MPa, or at least 950 MPa or greater than 950 MPa, or at least 1000 MPa or greater than 1000 MPa, or at least 1050 MPa or greater than 1050 MPa, or at least 1100 MPa or greater than 1100 MPa.

[0246] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a tensile secant modulus of 1% in the range of 900 to 1500 MPa, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a tensile secant modulus of 900 to 1400 MPa, or 900 to 1300 MPa, or 900 to 1250 MPa, or 950 to 1500 MPa, or 950 to 1400 MPa, or 950 to 1300 MPa, or 950 to 1250 MPa, or 1000 to 1500 MPa, or 1000 to 1400 It has an elastic modulus of elastic secant at 1% of MPa, or 1000-1300 MPa, or 1000-1250 MPa, or 1050-1500 MPa, or 1050-1400 MPa, or 1050-1300 MPa, or 1050-1250 MPa, or 1100-1500 MPa, or 1100-1400 MPa, or 1100-1300 MPa, or 1100-1250 MPa.

[0247] In some embodiments, a polyethylene composition or a plaque made from a polyethylene composition has an Izod impact strength value (also known as Izod impact value or Izod impact strength) of ≥4.0 ft-pounds / inch, or >4.5 ft-pounds / inch, or ≥5.0 ft-pounds / inch, or >5.0 ft-pounds / inch, or ≥6.0 ft-pounds / inch, or >6.0 ft-pounds / inch, or ≥6.5 ft-pounds / inch, or >6.5 ft-pounds / inch.

[0248] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an Izod impact strength value of at least 4.0 ft-pounds / inch. In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an Izod impact strength value of at least 6.0 ft-pounds / inch.

[0249] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an Izod impact strength value of 4.0 to 20.0 ft-pounds / inch, including any narrow range within this range and any value encompassed within these ranges. For example, in some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an Izod impact strength value of 4.0 to 18.0 ft-pounds / inch, or 4.0 to 16.0 ft-pounds / inch, or 4.0 to 14.0 ft-pounds / inch, or 4.0 to 13.0 ft-pounds / inch, or 5.0 to 20.0 ft-pounds / inch, or 5.0 to 18.0 ft-pounds / inch, or 5.0 to 16.0 ft-pounds / inch, or 5.0 to 14.0 ft-pounds / inch, or 5.0 to 13.0 ft-pounds / inch. It has an Izod impact strength value of 0.75 lbs / inch, or 6.0–20.0 ft·lbs / inch, or 6.0–18.0 ft·lbs / inch, or 6.0–16.0 ft·lbs / inch, or 6.0–14.0 ft·lbs / inch, or 6.0–13.5 ft·lbs / inch, or 6.5–20.0 ft·lbs / inch, or 6.5–18.0 ft·lbs / inch, or 6.5–16.0 ft·lbs / inch, or 6.5–14.0 ft·lbs / inch, or 6.5–13.0 ft·lbs / inch.

[0250] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has an Izod impact strength value of 4.0 to 13.0 ft-pounds / inch.

[0251] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition is ≥150 ft-pounds / inch 2 , or ≥175 ft-pounds / inch 2 , or ≥200 ft-pounds / inch 2 , or ≥215 ft-pounds / inch 2 , or ≥230 ft-pounds / inch 2 , or ≥240 ft-pounds / inch2 It has a tensile impact strength value (also known as tensile impact value or tensile impact strength).

[0252] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a load capacity of at least 230 ft-pounds / inch 2 It has a tensile impact strength value of [value].

[0253] In some embodiments, the polyethylene composition or plaque made from the polyethylene composition has a yield of 150 to 500 ft-pounds / inch 2 , or 150-450 ft-pounds / inch 2 , or 150-400 ft-pounds / inch 2 , or 150-375 ft-pounds / inch 2 , or 175-500 ft-pounds / inch 2 , or 175-450 ft-pounds / inch 2 , or 175-400 ft-pounds / inch 2 , or 175-375 ft-pounds / inch 2 , or 200-500 ft-pounds / inch 2 , or 200-450 ft-pounds / inch 2 , or 200-400 ft-pounds / inch 2 , or 200-375 ft-pounds / inch 2 , or 215-500 ft-pounds / inch 2 , or 215-450 ft-pounds / inch 2 , or 215-400 ft-pounds / inch 2 , or 215-375 ft-pounds / inch 2 , or 230-500 ft-pounds / inch 2 , or 230-450 ft-pounds / inch 2 , or 230-400 ft-pounds / inch 2 , or 230-375 ft-pounds / inch 2 , or 240-500 ft-pounds / inch 2, or 240-450 ft-pounds / inch 2 , or 240-400 ft-pounds / inch 2 , or 240-375 ft-pounds / inch 2 It has a tensile impact strength value of [value].

[0254] Additives may be optionally added to the polyethylene composition. Additives may be added to the polyethylene composition during the extrusion or compounding process, but other suitable known methods will be apparent to those skilled in the art. Additives may be added as is, or as part of a separate polymer component (i.e., not the first or second ethylene polymer described above) added during the extrusion or compounding process. Suitable additives known in the art include, but are not limited to, antioxidants, phosphates and phosphonites, nitrones, antacids, UV stabilizers, UV absorbers, metal deactivators, dyes, fillers and reinforcing agents, nanoscale organic or inorganic materials, antistatic agents, lubricants such as calcium stearate, anti-slip additives such as erucamide, and nucleating agents (including nucleating agents, pigments, or other chemicals that may impart a nucleating effect to the polyethylene composition). Optionally added additives are typically added in amounts up to 20% by weight (wt%).

[0255] One or more nucleating agents can be introduced into a polyethylene composition by kneading a mixture of the polymer (usually in the form of powder or pellets) and the nucleating agent. The nucleating agent can be used alone or in the form of a concentrate containing further additives such as stabilizers, pigments, antistatic agents, UV stabilizers, and fillers. It must be a material that is wetted or absorbed by the polymer, insoluble in the polymer, has a melting point higher than the polymer's melting point, and can be uniformly dispersed in the polymer molten material in the finest possible form (1-10 μm). Compounds known to have nucleating ability in polyolefins include salts of aliphatic monobasic or dibasic acids or arylalkyl acids (such as sodium succinate or aluminum phenylacetate); and alkali metal or aluminum salts of aromatic or alicyclic carboxylic acids (such as sodium β-naphthoate). Another compound known to have nucleating ability is sodium benzoate. The nucleating effect can be monitored microscopically by observing the degree of reduction in the size of spherulites formed by the aggregation of crystallites.

[0256] Examples of commercially available nucleating agents that can be added to polyethylene compositions include dibenzylidene sorbital ester (for example, the product sold by Milliken Chemical under the trademark MILLAD® 3988, and the product sold by Ciba Specialty Chemicals under the trademark IRGACLEAR®). Further examples of nucleating agents that can be added to polyethylene compositions include the cyclic organic structure (and its salts, e.g., disodium bicyclo[2.2.1]heptenedicarboxylate) disclosed in U.S. Patent No. 5,981,636; saturated versions of the structure disclosed in U.S. Patent No. 5,981,636 (disclosed in U.S. Patent No. 6,465,551; from Zhao et al. to Milliken); salts of certain cyclic dicarboxylic acids having a hexahydrophthalic acid structure (or "HHPA" structure) disclosed in U.S. Patent No. 6,599,971 (from Dotson et al. to Milliken); and cyclic dicarboxylic acid salts and salts thereof, such as phosphate esters disclosed in U.S. Patent No. 5,342,868 and sold by Asahi Denka Kogyo under the trade names NA-11 and NA-21, and divalent metal salts or metalloid salts (especially calcium salts) of the HHPA structure disclosed in U.S. Patent No. 6,599,971. For clarity, an HHPA structure generally comprises a ring structure having six carbon atoms in the ring and two carboxylic acid groups that are substituents on atoms adjacent to the ring structure. The other four carbon atoms in the ring may be substituted, as disclosed in U.S. Patent No. 6,599,971. One example is calcium 1,2-cyclohexanedicarboxylate (CAS Registry No. 491589-22-1). Further examples of nucleating agents that can be added to polyethylene compositions are disclosed in International Publication Nos. 2015 / 042561, 2015 / 042563, 2015 / 042562, and 2011 / 050042.

[0257] Many of the nucleating agents mentioned above can be difficult to mix with the polyethylene composition on which they form nucleation, and it is known that dispersing agents such as zinc stearate are used to mitigate this problem.

[0258] In some embodiments, the nucleating agent is well dispersed in the polyethylene composition.

[0259] In some embodiments, the amount of nucleating agent used is relatively small (5 to 3000 ppm by weight [based on the weight of the polyethylene composition]), so it will be understood by those skilled in the art that some care must be taken to ensure that the nucleating agent is well dispersed. In some embodiments, the nucleating agent is added to the polyethylene composition in a finely divided form (less than 50 microns, especially less than 10 microns) to facilitate mixing. This type of “physical blend” (i.e., a mixture of the nucleating agent and resin in solid form) is generally preferred over using a “masterbatch” of the nucleating agent (wherein the term “masterbatch” refers to embodiments in which the additive [in this case, the nucleating agent] is first melt-mixed with a small amount of polyethylene composition resin, and then the “masterbatch” is melt-mixed with the remaining bulk of the polyethylene composition resin).

[0260] In some embodiments, additives such as nucleating agents may be added to the polyethylene composition in a “masterbatch” manner, where the term “masterbatch” refers to an embodiment in which the additive (e.g., nucleating agent) is first melt-mixed with a small amount of polyethylene composition, and then the “masterbatch” is melt-mixed with the remaining bulk of the polyethylene composition.

[0261] In some embodiments, the polymer composition further comprises a nucleating agent or a mixture of nucleating agents.

[0262] In some embodiments, polyethylene compositions are used to form molded articles. For example, molded articles formed by rotational molding, continuous compression molding, and injection molding are possible. Such molded articles include, for example, tanks formed by rotational molding, and bottle caps, screw caps, and closures formed by compression molding or injection molding. However, those skilled in the art will understand that the compositions described above can also be used in other applications, but are not limited to, films, injection blow molding, blow molding, and sheet extrusion applications.

[0263] In some embodiments, the polyethylene compositions disclosed herein can be converted into molded articles.

[0264] In some embodiments, the polyethylene compositions disclosed herein can be used to manufacture articles by a rotational molding process.

[0265] In some embodiments, the polyethylene compositions disclosed herein can be converted into rotationally molded articles.

[0266] In some embodiments, as an alternative to rotational molding, the polyethylene compositions of the present disclosure can be used to manufacture articles by extrusion, compression, or injection molding processes.

[0267] In some embodiments, the polyethylene compositions of this disclosure can be used to manufacture articles by an inflation film process as an alternative to rotational molding.

[0268] <Rotomolded Articles> Typically, polyethylene compositions can be manufactured in the form of powder or pellets for use in a rotational molding process. The rotational molding process may further include process steps for manufacturing the polyethylene composition. Powder is preferably used for rotational molding, and its particle size may be 35 US mesh or less. Grinding may be performed at cryogenic temperatures if necessary. The polymer powder is then placed in a hollow mold and heated inside the mold while the mold is rotated. The mold is usually rotated in two axes, that is, simultaneously around two vertical axes. The mold is typically heated from the outside (generally using a forced air circulation oven). Generally, the rotational molding process steps include tumbling, heating, and melting the polymer powder, followed by agglomeration, fusion, or sintering, and cooling to remove the molded product.

[0269] The polyethylene compositions of this disclosure can be processed in a commercially available rotational molding machine in certain embodiments of this disclosure. The time and temperature used depend on factors including the thickness of the part being rotationally molded, and appropriate processing conditions can be easily determined by those skilled in the art. To give some non-limiting examples, the oven temperature range during the heating process can be 400°F to 800°F (204°C to 427°C), or about 500°F to about 700°F (about 260°C to about 371°C), or about 575°F to about 650°F (about 302°C to about 343°C).

[0270] After the heating process, the mold is cooled. The parts need to be sufficiently cooled so that they can be easily removed from the mold and maintain their shape. The mold may be removed from the oven while rotating it. First, cool air is blown onto the mold. The air may be at ambient temperature. After a controlled time, when the air has begun to cool the mold, a water spray may be used. The mold is rapidly cooled by the water. The water used may be cold tap water, for example, at a temperature of about 4°C (40°F) to about 16°C (60°F). After the water cooling process, another air cooling process may be performed. This may be a short process to dry the equipment by removing heat as the water evaporates.

[0271] The heating and cooling cycle times vary depending on the equipment used and the article being molded. Specific factors include the thickness of the part in the mold material. As a non-limiting example, the conditions for a 1 / 8-inch thick part in a steel mold may be as follows: the mold is heated in an oven with air at approximately 316°C (600°F) for approximately 15 minutes; the part is then cooled by forced air cooling at ambient temperature for approximately 8 minutes, followed by cooling by spraying with tap water at approximately 10°C (50°F) for approximately 5 minutes; optionally, the part may be cooled further by forced air cooling at ambient temperature for an additional 2 minutes.

[0272] During the heating and cooling processes, the mold containing the molded product is preferably rotated continuously. Typically, this is done along two vertical axes. The rotational speed of the mold around each axis is limited by the capabilities of the machine and the shape of the article being molded. A typical non-limiting range of operation that can be used in this disclosure is a rotational ratio of the major axis to the minor axis of about 1:8 to 10:1, or about 1:2 to 8:1.

[0273] Non-limiting examples of molded products that can be manufactured using rotational molding processes include custom tanks, water tanks, carts, transport cases and containers, coolers, sports and recreational equipment (boats, kayaks, etc.), toys, and play equipment.

[0274] The desirable physical properties of rotationally molded parts vary depending on the intended application. Non-limiting examples of desirable properties include flexural modulus (1% and 2% secant modulus), environmental stress crack resistance (ESCR), Shore hardness, thermal deflection temperature (HDT), VICAT softening point, Izod impact strength, ARM impact resistance, and color (whiteness and / or yellowness index).

[0275] In some embodiments, a rotationally molded article having an internal volume of at least about 2,500 liters, at least about 5,000 liters, at least about 10,000 liters, at least about 20,000 liters, at least about 50,000 liters, or at least about 100,000 liters is prepared using a polyethylene composition having a melt index (I2) of 1.0 to 3.0 g / 10 min or less than 3.0 g / 10 min.

[0276] In some embodiments, the rotationally molded product is a tank. In some embodiments, the rotationally molded product is a large tank.

[0277] In some embodiments, a polyethylene composition having a melt index (I2) of 1.0 to 3.0 g / 10 min or less than 3.0 g / 10 min is used to prepare a rotationally molded article having an internal volume of less than about 1,000,000 liters or less than about 500,000 liters.

[0278] In some embodiments, the process for producing a rotationally molded product includes the following steps: (i) filling a mold with a polyethylene composition; (ii) heating the mold in an oven to a temperature exceeding 280°C; (iii) rotating the mold around at least two axes; (iv) cooling the mold while it is rotating; and (v) opening the mold and removing the rotationally molded product.

[0279] <Additives and Auxiliaries - Rotational Molded Products> The polyethylene compositions described and the rotationally molded articles produced may optionally contain additives and auxiliaries depending on the intended use. Additives may be added to the polyethylene compositions during the extrusion or compounding process, but other suitable known methods will be apparent to those skilled in the art. Additives may be added as is or as part of a separate polymer component added during the extrusion or compounding process. Non-limiting examples of additives and auxiliaries include antiblocking agents, antioxidants, heat stabilizers, slip agents, processing aids, antistatic additives, colorants, dyes, fillers, light stabilizers, heat stabilizers, light absorbers, lubricants, pigments, plasticizers, nucleating agents, and combinations thereof. Non-limiting examples of suitable primary antioxidants include IRGANOX® 1010 [CAS Registry No. 6683-19-8] and IRGANOX 1076 [CAS Registry No. 2082-79-3]; both are available from BASF Corporation (Florham Park, New Jersey, USA). Some non-exclusive examples of suitable secondary antioxidants include IRGAFOS® 168 [CAS Reg. No. 31570-04-4], available from BASF Corporation (Florham Park, New Jersey, USA); Weston 705 [CAS Reg. No. 939402-02-5], available from SI Group (Woodlands, Texas, USA); and DOVERPHOS® LGP-11 [CAS Reg. No. 1227937-46-3], available from Dover Chemical Corporation (Dover, Ohio, USA). Optional additives are typically added in amounts up to 20% by weight (wt%).

[0280] One or more nucleating agents can be introduced into a polyethylene composition by kneading a mixture of the polymer (usually in the form of powder or pellets) and the nucleating agent. The nucleating agent can be used alone or in the form of a concentrate containing further additives such as stabilizers, pigments, antistatic agents, UV stabilizers, and fillers. It must be a material that is wetted or absorbed by the polymer, insoluble in the polymer, has a melting point higher than the polymer's melting point, and can be uniformly dispersed in the polymer molten material in the finest possible form (1-10 μm). Compounds known to have nucleating ability in polyolefins include salts of aliphatic monobasic or dibasic acids or arylalkyl acids (such as sodium succinate or aluminum phenylacetate); and alkali metal or aluminum salts of aromatic or alicyclic carboxylic acids (such as sodium β-naphthoate). Another compound known to have nucleating ability is sodium benzoate. The nucleating effect can be monitored microscopically by observing the degree of reduction in the size of spherulites formed by the aggregation of crystallites.

[0281] In some embodiments, the polyethylene compositions described and the rotationally molded articles produced may contain additives selected from the group including antioxidants, phosphites and phosphonites, nitrones, antacids, ultraviolet stabilizers, ultraviolet absorbers, metal deactivators, dyes, fillers and reinforcing agents, nanoscale organic or inorganic materials, antistatic agents, mold release agents such as zinc stearate, and nucleating agents (including nucleating agents, pigments, or other chemicals that may impart a nucleating effect to the polyethylene composition).

[0282] In some embodiments, the additives that can be added are added in an amount of up to 20% by weight (wt%).

[0283] Additives can be added to the polyethylene composition during the extrusion or compounding process, but other suitable known methods will be apparent to those skilled in the art. Additives can be added as is, or as part of a separate polymer component added during the extrusion or compounding process.

[0284] A more detailed list of additives that can be added to the polyethylene compositions of this disclosure and used in rotationally molded articles is given below:

[0285] <Phosphite (e.g., aryl monophosphite)> As used herein, the term aryl monophosphite means a phosphite stabilizer that (1) contains only one phosphorus atom per molecule; and (2) contains at least one aryl oxide (also called phenoxide) radical bonded to phosphorus.

[0286] In some embodiments, the aryl monophosphite comprises three aryl oxide radicals, for example, trisphenyl phosphite is the simplest member of this preferred group of aryl monophosphites.

[0287] In some embodiments, the aryl monophospite has at least one C1-C aryl oxide group. 10 This includes alkyl substituents. These substituents may be linear (in the case of nonyl substituents) or branched (in the case of isopropyl substituents or tert-butyl substituents, etc.).

[0288] Non-limiting examples of aryl monophosphites that can be used in embodiments of the present disclosure include triphenyl phosphite; diphenylalkyl phosphite; phenyl dialkyl phosphite; tris(nonylphenyl) phosphite [WESTON 399, available from SI Group]; tris(2,4-di-tert-butylphenyl) phosphite [IRGAFOS 168, available from Ciba Specialty Chemicals Corp.]; and bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite [IRGAFOS 38, available from BASF Corp.]; and 2,2',2''-nitrilo[triethyltris(3,3'5,5'-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl) phosphite [IRGAFOS 12, available from BASF Corp.].

[0289] In some embodiments, the amount of aryl monophosphine added to the polyethylene composition is 200 to 2,000 ppm (based on the weight of the polymer), or 300 to 1,500 ppm, or 400 to 1,000 ppm.

[0290] <Phosphites, phosphonates (e.g., diphosphites, diphosphonates)> As used herein, the term diphosphite refers to a phosphite stabilizer containing at least two phosphorus atoms per phosphite molecule (similarly, the term diphosphonite refers to a phosphonite stabilizer containing at least two phosphorus atoms per phosphonite molecule).

[0291] Non-limiting examples of diphosphites and diphosphonates that can be used in embodiments of this disclosure include distearyl pentaerythritol diphosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite [ULTRANOX® 626, available from SI Group]; bis(2,6-di-tert-butyl-4-methylpenyl) pentaerythritol diphosphite; bisdecyloxy pentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl) pentaerythritol diphosphite, bis(2,4,6-tri-tert-butylphenyl) pentaerythritol diphosphite, tetrakis(2,4-di-tert-butylphenyl) 4,4'-biphenylenediphosphonite [HOSTANOX Examples include P-EPQ (registered trademark, available from Clariant); and bis(2,4-dicumylphenyl)pentaerythritol diphosphite [DOVERPHOS S9228-T or DOVERPHOS S9228-CT]; and P-EPQ (CAS number 119345-01-06), an example of a commercially available diphosphonite.

[0292] In some embodiments, the diphosphite and / or diphosphonite added to the polyethylene composition is added at concentrations of 200 ppm to 2,000 ppm (based on the weight of the polymer), 300 to 1,500 ppm, or 400 to 1,000 ppm.

[0293] In some embodiments, the use of diphosphite is preferred over the use of diphosphonite.

[0294] In some embodiments, the most preferred diphosphites are those available under the trademarks DOVERPHOS S9228-CT and ULTRANOX 626.

[0295] <Hindered phenol-based antioxidants> The antioxidant may be any of the molecules conventionally used as hindered phenol antioxidants or primary antioxidants for stabilizing polyolefins. Suitable examples include 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(1-methylcyclohexyl)-4,6-dimethylphenol, 2,6-di-octadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, and 2,6-di-tert-butyl-4-methoxymethylphenol.

[0296] Two (non-limiting) examples of suitable hindered phenol antioxidants that can be used in embodiments of the present disclosure are sold by BASF Corporation under the trademark IRGANOX 1010 (CAS Registry No. 6683-19-8) and the trademark IRGANOX 1076 (CAS Registry No. 2082-79-3).

[0297] In some embodiments, the amount of hindered phenol antioxidant added to the polyethylene composition is 100 to 2000 ppm, or 400 to 1000 ppm (based on the weight of the polymer).

[0298] <Long-term tranquilizer> Plastic components intended for long-term use may, in some embodiments of this disclosure, contain at least one hindered amine light stabilizer (HALS). HALS are well known to those skilled in the art.

[0299] When using HALS, in some embodiments, the HALS may be a commercially available material and may be used in conventional methods and quantities.

[0300] Commercially available HALS that can be used in embodiments of this disclosure include those sold by BASF Corporation under the trademarks CHIMASSORB® 119; CHIMASSORB 944; CHIMASSORB 2020; TINUVIN® 622 and TINUVIN 770, and those sold by Solvay under the trademarks CYASORB® UV 3346, CYASORB UV 3529, CYASORB UV 4801 and CYASORB UV 4802. In some embodiments of this disclosure, TINUVIN 622 is preferred. In other embodiments of this disclosure, the use of mixtures of two or more HALS is also envisioned.

[0301] In some embodiments, preferred HALS include bis(2,2,6,6-tetramethylpiperidyl)-sebacate; bis-5(1,2,2,6,6-pentamethylpiperidyl)-sebacate; n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate bis(1,2,2,6,6-pentamethylpiperidyl) ester; condensation product of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidine and succinic acid; N,N'-(2,2,6,6 Examples of HALS selected from tris-(2,2,6,6-tetramethylpiperidyl)-hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine; tris-(2,2,6,6-tetramethylpiperidyl)-nitrilotriacetate, tetrakis-(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarbonate; and 1,1'(1,2-ethanediyl)-bis-(3,3,5,5-tetramethylpiperazinone).

[0302] <Hydroxylamine> Hydroxylamines and their derivatives (including amine oxides) are known to be used as additives in polyethylene compositions used to prepare rotationally molded parts (for example, as disclosed in U.S. Patent No. 6,444,733), and in embodiments of this disclosure, the hydroxylamines and derivatives disclosed in this patent may also be suitable for use.

[0303] In some embodiments, hydroxylamines useful for inclusion in polyethylene compositions can be selected from N,N-dialkylhydroxylamines, a commercially available example being N,N-di(alkyl)hydroxylamine sold as IRGASTAB FS 042 (BASF), which has been reported to be prepared by direct oxidation of N,N-di(hydrogenated) fatamines.

[0304] <Additive Package> In some embodiments, the polyethylene composition contains an additive package comprising a hindered monophosphite, a diphosphite, a hindered amine light stabilizer, and at least one additional additive selected from the group consisting of hindered phenols and hydroxylamines.

[0305] In some embodiments, the additive package contains hydroxylamine.

[0306] In some embodiments, the hydroxylamine is an N,N-dialkylhydroxylamine.

[0307] In some embodiments, the hydroxylamine is IRGASTAB FS 042 (manufactured by BASF).

[0308] In some embodiments, hydroxylamine is present at a concentration of at least about 400 ppm by weight, or at least about 500 ppm by weight, or at least about 600 ppm by weight, or at least about 700 ppm by weight, or at least about 750 ppm by weight, or at least about 800 ppm by weight.

[0309] In some embodiments, hydroxylamine is present at a concentration of at least about 750 ppm by weight.

[0310] In some embodiments, hydroxylamine is present at concentrations of about 400 ppm by weight, or about 500 ppm by weight, or about 600 ppm by weight, or about 700 ppm by weight, or about 750 ppm by weight, or about 800 ppm by weight.

[0311] In embodiments of this disclosure, the amount of hydroxylamine added to the polyethylene composition is 100 to 2,000 ppm by weight, or 400 to 1,000 ppm by weight, or 600 to 1,000 ppm by weight, or 700 to 1,000 ppm by weight, or 800 to 1,000 ppm by weight.

[0312] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, are expressed as appropriate in their specific forms, or as means for performing the disclosed functions, or as methods or processes for obtaining the disclosed results, and these features can be used individually or in any combination to realize the present invention in various forms.

[0313] The present invention has been described in conjunction with the exemplary embodiments described above, but those skilled in the art will see from reading this disclosure that many equivalent modifications and variations are possible. Therefore, the exemplary embodiments of the present invention described above are illustrative and not limiting. Various modifications can be made to the embodiments described above without departing from the spirit and scope of the invention.

[0314] To avoid any doubt, the theoretical explanations provided herein are provided for the purpose of enhancing the reader's understanding. The inventors do not wish to be bound by any of these theoretical explanations.

[0315] The headings used herein are for structural purposes only and should not be construed as limiting the subject matter described herein.

[0316] Throughout this specification and in the subsequent claims, unless otherwise specified in the context, the words “comprise” and “include,” as well as variations such as “comprises,” “comprising,” and “including,” shall be understood to mean including the integer, process, or group of integers or processes described, but not to exclude other integers, processes, or groups of integers or processes.

[0317] Note that, as used herein and in the appended claims, the singular forms “a,” “an,” and “the” refer to multiple subjects unless otherwise specified in the context. In this specification, ranges may be expressed as “approximately” from one particular value and / or “approximately” to another particular value. Where such ranges are expressed, another embodiment includes that particular value and / or that other particular value. Similarly, where a value is expressed as an approximation using the preceding term “approximately,” it is understood that the particular value forms another embodiment. The term “approximately” with respect to numbers is arbitrary and means, for example, + / - 10%.

[0318] Further non-limiting details of this disclosure are provided in the following embodiments. The embodiments are presented for illustrative purposes of selected embodiments of this disclosure, and it is understood that the examples presented are not intended to limit the scope of the presented claims. [Examples]

[0319] <General Test Procedures> Prior to testing, each polymer test specimen was conditioned at 23±2°C and 50±10% relative humidity for at least 24 hours, and the subsequent testing was carried out at 23±2°C and 50±10% relative humidity. In this specification, the term "ASTM conditions" refers to a laboratory maintained at 23±2°C and 50±10% relative humidity, where the test specimens were conditioned for at least 24 hours prior to testing. ASTM refers to the American Society for Testing and Materials.

[0320] <density> The density of the polyethylene composition was determined using ASTM D792-13 (November 1, 2013).

[0321] <Melt Index> The melt index of the polyethylene composition was determined using ASTM D1238 (August 1, 2013). Melt index: I2, I6, I 10 , and I 21 These were measured at 190°C using weights of 2.16 kg, 6.48 kg, 10 kg, and 21.6 kg, respectively. In this specification, the term "stress index," or its acronym "S.Ex.", is defined by the following relationship: S.Ex.=log(I6 / I2) / log(6480 / 2160) (In the formula, I6 and I2 are the melt flow rates measured at 190°C using loads of 6.48 kg and 2.16 kg, respectively). In this disclosure, the melt index may be expressed in units of g / 10 min, g / 10 min, dg / min, or dg / min, and these units are equivalent.

[0322] <Gel Permeation Chromatography (GPC)> Molecular weight M of polyethylene composition n M w M z , and polydispersity (M w / M nThe ) was determined using ASTM D6474-12 (December 15, 2012). Polymer sample solutions (1-2 mg / mL) were prepared by heating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating it on a wheel in an oven at 150°C for 4 hours. To stabilize the polymer against oxidative degradation, an antioxidant (2,6-di-tert-butyl-4-methylphenol (BHT)) was added to the mixture. The BHT concentration was 250 ppm. The sample solutions were chromatographed at 140°C at a flow rate of 1.0 mL / min using TCB as the mobile phase in a PL220 high-temperature chromatography unit equipped with four SHODEX® columns (HT803, HT804, HT805, and HT806), with differential refractive index (DRI) as the concentration detector. To protect the GPC columns from oxidative degradation, BHT was added to the mobile phase at a concentration of 250 ppm. The sample injection volume was 200 μL. GPC raw data was processed with CIRRUS® GPC software. The GPC column was calibrated with a narrow-distribution polystyrene standard. Polystyrene molecular weight was converted to polyethylene molecular weight using the Mark-Houwink formula, as described in ASTM D6474-12 (December 15, 2012).

[0323] <Triple detection size exclusion chromatography (3D-SEC)> Polyethylene composition sample (polymer) solutions (1-3 mg / mL) were prepared by heating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating it on a wheel in an oven at 150°C for 4 hours. To stabilize the polymer against oxidative degradation, an antioxidant (2,6-di-tert-butyl-4-methylphenol (BHT)) was added to the mixture. The BHT concentration was 250 ppm. The sample solutions were chromatographed at 140°C using a PL 220 high-temperature chromatography unit equipped with a differential refractive index (DRI) detector, dual-angle light scattering detectors (15° and 90°), and a differential viscometer. The SEC columns used were either four SHODEX columns (HT803, HT804, HT805, and HT806) or four PL Mixed ALS or BLS columns. TCB was used as the mobile phase at a flow rate of 1.0 mL / min, and BHT was added to the mobile phase at a concentration of 250 ppm to protect the SEC column from oxidative degradation. The sample injection volume was 200 μL. Raw SEC data was processed with CIRRUS GPC software to calculate the absolute molar mass and intrinsic viscosity ([η]). The term "absolute" molar mass was used to distinguish between the absolute molar mass determined by 3D-SEC and the molar mass determined by conventional SEC. Viscosity-average molar mass (M) determined by 3D-SEC v The long-chain branching coefficient (LCBF) was determined using the following formula.

[0324] <gpc-ftir> Polyethylene composition (polymer) solutions (2-4 mg / mL) were prepared by heating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating it on a wheel in an oven at 150°C for 4 hours. An antioxidant (2,6-di-tert-butyl-4-methylphenol (BHT)) was added to the mixture to stabilize the polymer against oxidative degradation. The BHT concentration was 250 ppm. The sample solutions were chromatographed using TCB as the mobile phase at a flow rate of 1.0 mL / min and 140°C in a Waters GPC 150C chromatography unit equipped with four SHODEX columns (HT803, HT804, HT805, HT806). As a detection system, an FTIR spectrometer and a heated FTIR flow-through cell were connected to the chromatography unit via a heated transfer line. BHT was added to the mobile phase at a concentration of 250 ppm to protect the SEC columns from oxidative degradation. The sample injection volume was 300 μL. Raw FTIR spectra were processed with OPUS FTIR software, and polymer concentrations and methyl content were calculated in real time using the chemometric software (PLS technique) associated with OPUS. Polymer concentrations and methyl content were then obtained and baseline-corrected using CIRRUS GPC software. SEC columns were calibrated with narrow-distribution polystyrene standards. Polystyrene molecular weights were converted to polyethylene molecular weights using the Mark-Houwink formula, as described in ASTM standard test method D6474. Comonomer content was calculated based on the polymer concentrations and methyl content predicted by the PLS technique, as described in Paul J. DesLauriers, Polymer 43, pp. 159–170 (2002); incorporated herein by reference.

[0325] The GPC-FTIR method measures the total methyl content, including methyl-terminated groups located at the ends of each polymer chain. Therefore, raw GPC-FTIR data needs to be corrected by subtracting the contribution from the methyl-terminated groups. To clarify, raw GPC-FTIR data overestimates the amount of short-chain branching (SCBs), and this overestimation increases as the molecular weight (M) decreases. In this disclosure, raw GPC-FTIR data were corrected using the 2-methyl correction. Given a molecular weight (M), the following formula applies: N E =28000 / M used for methyl terminal group (N E Calculate the number of N E (M-dependent) was subtracted from the raw GPC-FTIR data to create SCB / 1000C (2-methyl corrected) GPC-FTIR data.

[0326] <Unsaturated content> The amount of unsaturated groups, i.e., double bonds, in the polyethylene compositions was determined according to ASTM D3124-98 (vinylidene unsaturated, published March 2011) and ASTM D6248-98 (vinyl and trans unsaturated, published July 2012). Polymer samples were (a) first subjected to carbon disulfide extraction to remove any additives that may interfere with the analysis; (b) the samples (pellets, films, or granules) were pressed to form plaques of uniform thickness (0.5 mm); and (c) the plaques were analyzed by FTIR.

[0327] <Comonomer content: Fourier transform infrared (FTIR) spectroscopy> The amount of comonomers in the polyethylene composition was determined by FTIR and reported as the short-chain branch (SCB) content with dimensions of CH3# / 1000C (number of methyl branches per 1000 carbon atoms). This test was completed using compression-molded polymer plaques and a Thermo-Nicolet 750 Magna-IR spectrophotometer according to ASTM D6645-01 (2001). The polymer plaques were prepared using a compression molding apparatus (Wabash-Genesis series press) according to ASTM D4703-16 (April 2016).

[0328] <Composition Distribution Branching Index (CDBI) by CTREF> The "Composition Distribution Branching Index" or "CDBI" of the disclosed examples and comparative examples was determined using a Crystallizing-TREF unit ("CTREF" unit) commercially available from Polymer Char (Valencia, Spain). The acronym "TREF" refers to Temperature Rising Elution Fractionation. A sample (80 - 100 mg) of the polyethylene composition was placed in the reactor of the Polymer Char Crystallizing-TREF unit, and the reactor was filled with 35 ml of 1,2,4-trichlorobenzene (TCB), heated to 150°C, and held at this temperature for 2 hours to dissolve the sample. Next, an aliquot (1.5 mL) of the TCB solution was loaded onto a Polymer Char TREF column packed with stainless steel beads, and the column was equilibrated at 110°C for 45 minutes. Then, the polyethylene composition was crystallized from the TCB solution within the TREF column by slowly cooling the TREF column from 110°C to 30°C at a cooling rate of 0.09°C per minute. Thereafter, the TREF column was equilibrated at 30°C for 30 minutes. Next, while slowly raising the temperature of the TREF column from 30°C to 120°C at a heating rate of 0.25°C per minute, a pure TCB solvent was passed through the column at a flow rate of 0.75 mL / min to elute the crystallized polyethylene composition from the TREF column. Using Polymer Char software, a TREF distribution curve was created when the polyethylene composition eluted from the TREF column. That is, the TREF distribution curve is a plot of the amount (or intensity) of the polymer material eluting from the column as a function of the TREF elution temperature. For each polyethylene composition analyzed, CDBI 50 was calculated. "CDBI 50 The TREF elution temperature is defined as the percentage of polymers whose composition is within 50% of the median comonomer composition (25% on each side of the median comonomer composition). This is calculated from the TREF composition distribution curve and the normalized cumulative integral of the TREF composition distribution curve. Those skilled in the art will understand that a calibration curve is necessary to convert the TREF elution temperature into comonomer content, i.e., the amount of comonomer in the polyethylene composition fraction that elutes at a specific temperature. The preparation of such a calibration curve is described in the prior art, for example, Wild et al., J. Polym. Sci., Part B, Polym. Phys., Vol. 20(3), pp. 441-455.

[0329] <Crystallization elution fractionation (CEF)> Crystallization elution fractionation (CEF) is also referred to as TREF-CEF in this document. A polymer sample (20-25 mg) was weighed into a sample vial and loaded into the autosampler of the Polymer Char CEF unit. The vial was filled with 6-7 mL of 1,2,4-trichlorobenzene (TCB) and heated to the desired dissolution temperature (e.g., 160°C) for 2 hours at a shaking rate of level 3. Next, the solution (0.5 mL) was loaded into a CEF column (two CEF columns purchased from Polymer Char and installed in series). After equilibration at a predetermined stabilization temperature (e.g., 115°C) for 5 minutes, the polymer solution was cooled from the stabilization temperature to 30°C to crystallize. After equilibration at 30°C for 10 minutes, the crystallized sample was eluted with TCB while increasing the temperature from 30°C to 110°C. The CEF column was washed at 150°C for 5 minutes at the end of the analysis. Other CEF analysis conditions were: cooling rate 0.5°C / min, flow rate during crystallization 0.02 mL / min, heating rate 1.0°C / min, and flow rate during elution 2.0 mL / min. The data were processed using an Excel spreadsheet.

[0330] <Hexane extract> Hexane extracts were determined in accordance with Federal Regulation 21 CFR §177.1520 Para(c) 3.1 and 3.2. The amount of hexane-extractable substances in the sample was determined by gravimetric analysis.

[0331] <Neutron activation analysis (NAA)> Catalyst residues in polyethylene compositions were determined using neutron activation analysis (NAA) as follows: Polymer samples were packed into radiation vials (made of ultra-high-purity polyethylene, internal capacity 7 mL), and the sample weight was recorded. Using a pneumatic transfer system, the samples were placed inside a SLOWPOKE® reactor (Atomic Energy of Canada Limited, Ottawa, Ontario, Canada) and irradiated for 30-600 seconds for elements with short half-lives (e.g., Ti, V, Al, Mg, and Cl) or 3-5 hours for elements with long half-lives (e.g., Zr, Hf, Cr, Fe, and Ni). The average thermal neutron flux inside the reactor was 5 × 10⁻¹⁶. 11 / cm 2 The irradiation time was / s. After irradiation, the sample was removed from the reactor and aged to decay its radioactivity; elements with short half-lives were aged for 300 seconds, and elements with long half-lives were aged for several days. After aging, the gamma-ray spectrum of the sample was recorded using a germanium semiconductor gamma-ray detector (Ortec model GEM55185, Advanced Measurement Technology Inc., Oak Ridge, Tennessee, USA) and a multi-channel analyzer (Ortec model DSPEC Pro). The amount of each element in the sample was calculated from the gamma-ray spectrum and recorded as parts per million (ppm) relative to the total weight of the polymer sample. The NAA system was calibrated using a Specpure standard (1000 ppm solution of the desired element (purity over 99%)). 1 mL of the solution (of the target element) was pipetteed onto a 15 mm × 800 mm rectangular paper filter and air-dried. The filter paper was then placed in a 1.4 mL polyethylene irradiation vial and analyzed with the NAA system. Use the standard to determine the sensitivity (counts / μg) of the NAA procedure.

[0332] <Dynamic mechanical analysis (DMA)> Vibrational shear measurements were performed at small strain amplitudes, and linear viscoelastic functions were obtained in a frequency range of 0.02 to 126 rad / s at 190°C in an N2 atmosphere, with a strain amplitude of 10%, and 5 points per 10 points. Frequency sweep experiments were performed using a TA Instruments DHR3 stress-controlled rheometer with a cone angle of 5°, a truncated head of 137 μm, and a conical plate shape with a diameter of 25 mm. In these experiments, sinusoidal strain waves were applied, and the stress response was analyzed in terms of linear viscoelastic functions. The zero shear rate viscosity (η0) based on the DMA frequency sweep results was predicted by the Ellis model (see RBBird et al., "Dynamics of Polymer Liquids. Volume 1: Fluid Mechanics," Wiley-Interscience Publications (1987), p. 228) or the Carreau-Yasuda model (see K. Yasuda (1979) PhD Thesis, IT Cambridge). Dynamic rheological data was analyzed using rheometer software (i.e., Rheometrics RHIOS V4.4 or Orchestrator Software) to determine the melt modulus G'(G''=500) at a reference melt viscosity (G'') value of G''=500 Pa. Where necessary, values ​​were obtained by interpolation between available data points using Rheometrics software. The term "storage modulus" G'(co), also called "modulus," is a function of the applied frequency co and is defined as the stress in phase with the strain in sinusoidal deformation divided by the strain. On the other hand, the term "viscosity" G''(ω), also called "loss modulus," is similarly a function of the applied frequency ω and is defined as the stress out of phase with the strain divided by the strain. These moduli of elasticity, as well as other linear viscoelastic and dynamic rheological parameters, are well known to those skilled in the art, for example, as discussed by G. Marin in Chapter 10, "Oscillatory Rheometry," of "Oscillatory Rheometry" edited by A.A.Collyer and D.W.C.Legg (Rheological Measurement, Elsevier, 1988).

[0333] Shear viscosity index SHI (1,100) This was calculated as the ratio of the complex viscosity estimated at a shear stress of 1 kPa to the complex viscosity estimated at a shear stress of 100 kPa. Shear viscosity reduction index SHI (1,100) This provides information on the shear viscosity reduction behavior of polymer molten materials. High values ​​indicate a strong dependence of viscosity on changes in deformation rate (shear or frequency).

[0334] The evaluation of the relative modulus is based on measurements performed at low frequencies best suited to the conditions related to powder sintering and densification in rotational molding. The relative modulus was evaluated based on the ratio of G' to G'' at a frequency of 0.05 rad / s (or 0.5 rad / s) from DMA frequency sweep measurements performed at 190°C. Data reported in the literature indicate that resin compositions with high relative moduli tend to be difficult to process due to slow powder densification. Wang and Kontopoulou reported suitable rotational moldability for a blend composition characterized by a high relative modulus of 0.125 (2004). Their study investigated the effect of plastomer content on the rotational moldability of polypropylene (WQ Wang and M. Kontopoulou (2004) Polymer Engineering and Science, Vol. 44, No. 9, pp. 1662-1669). Further analysis of the results published by Wang and Kontopoulou shows that compositions with higher plastomer content exhibit an increased relative modulus (G' / G'' > 0.13), and correspondingly, it becomes more difficult to achieve complete densification during rotational molding evaluation.

[0335] In this disclosure, the LCBF (Long Chain Branching Factor) was determined using η0 obtained by DMA (see U.S. Patent No. 10,442,921).

[0336] <Melting Strength> Melt strength is measured at 190°C using a Rosand RH-7 capillary rheometer (barrel diameter = 15 mm) with a 2 mm diameter flat die and an L / D ratio of 10:1. Pressure transducer: 10,000 psi (68.95 MPa). Piston speed: 5.33 mm / min. Conveying angle: 52°. Incremental conveying rate: 50-80 m / min 2 or 65±15m / min 2 The polymer molten material is extruded through a capillary die at a constant rate, and the polymer strand is then drawn out at an increasing transport rate until it bursts. The maximum steady-state value of the force in the plateau region of the force-time curve is defined as the melt strength of the polymer. The melt strength elongation ratio is defined as the ratio of the velocity at the pulley to the velocity at the die exit.

[0337] <Long-chain branching coefficient (LCBF)> LCBF (dimensionless) was determined for polyethylene compositions using the method described in U.S. Patent No. 10,442,921, which is incorporated herein by reference.

[0338] The calculation of the long-chain branching coefficient ("LCBF") involves multi-dispersion-corrected zero shear viscosity (ZSV), as detailed in the following paragraphs. c ) and short-chain branched ("SCB") corrected intrinsic viscosity (IV c ) is necessary.

[0339] Zero shear viscosity (ZSV) with dimensions of Poise c The correction for ) was made as shown in equation (1):

number

[0340] Intrinsic viscosity (IV) with dimensions of dL / g c The correction for ) was made as shown in equation (2):

number

[0341] A "linear" ethylene copolymer (or linear ethylene homopolymer) that does not contain LCB or contains LCB at undetectable levels lies on the baseline defined by formula (3).

number

[0342] The LCBF is calculated by the following formula, which defines the horizontal shift (S) from the linear baseline. h ) and vertical shift (S v ) was done based on:

number

number

[0343] In equations (4) and (5), ZSV c and IV c However, each must have dimensions of poise and dL / g, respectively.

[0344] Horizontal shift (S h ) is the intrinsic viscosity (IV c ZSV when ) is constant c It is a shift of , and if we remove the log function, its physical meaning becomes clear. That is, it is the ratio of two zero shear viscosities, and the same IV c ZSV of linear ethylene copolymer (or linear ethylene homopolymer) having c ZSV of the test sample c This is the horizontal shift (S h ) was dimensionless.

[0345] Vertical shift (S v ) is zero shear viscosity (ZSV). c IV when ) is constant c It is a shift, and if we remove the log function, its physical meaning becomes clear. That is, it is the ratio of the two intrinsic viscosities, and the IV of the test sample. c For the same ZSV c IV of a linear ethylene copolymer (or linear ethylene homopolymer) having c This is the vertical shift (S v ) was dimensionless.

[0346] The dimensionless long-chain branching coefficient (LCBF) was defined by equation (6):

number

[0347] In some embodiments of this disclosure, an ethylene polymer having LCB (e.g., a polyethylene composition) is characterized by having an LCBF (dimensionless) of 0.0010 or greater; in contrast, an ethylene polymer without LCB (or in which LCB cannot be detected) is characterized by having an LCBF (dimensionless) of less than 0.0010.

[0348] <Impact properties> Izod impact performance was determined according to ASTM D256. Izod impact test specimens were notched to promote stress concentration points that induce brittle fracture rather than ductile fracture.

[0349] The tensile impact performance was determined according to ASTM D1822.

[0350] <Tensile properties> The following tensile properties were determined using ASTM D638: yield elongation (%), yield strength (MPa), ultimate elongation (%), ultimate strength (MPa), and 1% and 2% secant modulus (MPa).

[0351] <Bending properties> The bending properties, specifically the 2% secant modulus of the bending wire, were determined using ASTM D790-10 (published April 2010).

[0352] <Environmental Stress Crack Resistance (ESCR)> Plaques molded from polyethylene compositions were tested according to the following ASTM method: Bending strip environmental stress crack resistance (ESCR), ASTM D1693; ESCR test under ASTM D1693 "B" conditions (temperature 50°C) was performed using IGEPAL CO-630 (nonylphenoxypoly(ethyleneoxy)ethanol, branched; formula: 4-(branched C9H 19 )-phenyl-[OCH2CH2] n The test was conducted using a 100% solution of (containing -OH, where the subscript n is 9-10) and a 10% solution of IGEPAL CO-630. A person skilled in the art would know that the test using the 10% solution ("B 10 ") is a test using a 100% solution ("B 100 Something more difficult than ""), namely, B 10 The value of is typically B 100 You will notice that it is lower than the value.

[0353] Plaques molded from polyethylene compositions were tested according to the following ASTM method: Bending strip environmental stress crack resistance (ESCR), ASTM D1693; ESCR test under ASTM D1693 "A" conditions (temperature 50°C) was performed using IGEPAL CO-630 (nonylphenoxypoly(ethyleneoxy)ethanol, branched; formula: 4-(branched C9H 19 )-phenyl-[OCH2CH2] n The test was conducted using a 100% solution of (containing -OH, where the subscript n is 9 to 10) and a 10% solution of IGEPAL CO-630. A person skilled in the art would know that the test using the 10% solution ("A 10 ") is a test using a 100% solution ("A 100 Something more difficult than "), namely, A 10 The value of is typically A 100 You will notice that it is lower than the value.

[0354] <Preparation of polyethylene composition> The polyethylene composition was prepared using a mixed binary catalyst system in an "in-series" double reactor solution polymerization process. As a result, the polyethylene composition contained a first ethylene copolymer prepared with a single-site catalyst and a second ethylene copolymer prepared with a multi-site catalyst. A "in-series" double reactor, solution-phase polymerization process, including one using a mixed binary catalyst, is described in U.S. Patent Application Publication 2018 / 0305531. Essentially, in the "in-series" double reactor system, the outlet flow from the first polymerization reactor (R1) flows directly into the second polymerization reactor (R2). The pressure in R1 was approximately 14 MPa to 18 MPa, while R2 was operated at a lower pressure to facilitate continuous flow from R1 to R2. Both R1 and R2 were continuous stirred reactors (CSTRs) and stirred under conditions that ensured thorough mixing of the reactor contents. The process was operated continuously by supplying fresh process solvent, ethylene, 1-octene, and hydrogen to the reactors and removing the product. In this example of the present invention, although the comonomer is not directly supplied to the downstream second reactor R2 (i.e., fresh 1-octene is supplied only to the first reactor R1), it should be noted that the presence of unreacted 1-octene flowing from the first reactor to the second reactor causes copolymerization with ethylene in the second reactor, thus forming an ethylene copolymer in the second reactor. Methylpentane was used as the process solvent (a commercially available blend of methylpentane isomers). The volume of the first CSTR reactor (R1) was 3.2 gallons (12 L), and the volume of the second CSTR reactor (R2) was 5.8 gallons (22 L). The monomer (ethylene) and comonomer (1-octene) were purified using a conventional feed preparation system (such as contact with various absorption media to remove impurities such as water, oxygen, and polar contaminants) before being added to the reactors. The reactor feed was pumped into the reactors in the ratios shown in Table 1. The average residence time in a reactor is calculated by dividing the average flow rate by the reactor volume and is primarily influenced by the amount of solvent flowing through each reactor and the total amount of solvent flowing through the solution process.

[0355] The following single-site catalyst (SSC) components were used to prepare the first ethylene copolymer in the first reactor (R1): diphenylmethylene (cyclopentadienyl)(2,7-di-t-butylfluorenyl)hafnium dimethyl [(2,7-tBu2Flu)Ph2C(Cp)HfMe2]; methylaluminoxane (MMAO-07); trityltetrakis(pentafluorophenyl)borate (tritylborate); and 2,6-di-tert-butyl-4-ethylphenol (BHEB). Methylaluminoxane (MMAO-07) and 2,6-di-tert-butyl-4-ethylphenol were pre-mixed in-line and combined with diphenylmethylene (cyclopentadienyl)(2,7-di-t-butylfluorenyl)hafnium dimethyl and trityltetrakis(pentafluorophenyl)borate immediately before entering the polymerization reactor (R1). Suitable solvents for supplying single-site catalyst components to the reactor include methylpentane and orthoxylene. The efficiency of the single-site catalyst formulation was optimized by adjusting the molar ratio of the catalyst components and the R1 catalyst inlet temperature.

[0356] The second ethylene copolymer was prepared in a second reactor (R2) using the following Ziegler-Natta (Zn) catalyst components: butylethylmagnesium; tertiary butyl chloride; titanium tetrachloride; diethylaluminum ethoxide; and triethylaluminum. Using methylpentane as the catalyst solvent, an in-line Ziegler-Natta catalyst formulation was prepared using the following steps and then injected into the second reactor (R2). In step 1, a solution of triethylaluminum and butylethylmagnesium (Mg:Al=20, molars:molars) was mixed with a solution of tertiary butyl chloride and reacted for approximately 30 seconds to produce a MgCl2 support. In step 2, a solution of titanium tetrachloride was added to the mixture formed in step 1 and reacted for approximately 14 seconds before being injected into the second reactor (R2). The in-line Ziegler-Natta catalyst was activated in the reactor by injecting a solution of diethylaluminum ethoxide into R2. The amount of titanium tetrachloride added to the reactor is shown in Table 1. The efficiency of the in-line Ziegler-Natta catalyst formulation was optimized by adjusting the molar ratio of the catalyst components.

[0357] Polymerization in the continuous solution polymerization process was terminated by adding a catalyst deactivator to the second reactor outlet flow. The catalyst deactivator used was octanoic acid (caprylic acid), commercially available from P&G Chemicals (Cincinnati, Ohio, USA). The catalyst deactivator was added so that the moles of the fatty acid added amounted to 50% of the total molar amount of hafnium, titanium, and aluminum added to the polymerization process; for clarity, the moles of added octanoic acid = 0.5 × (moles of hafnium + moles of titanium + moles of aluminum).

[0358] The ethylene interpolymer product was recovered from the process solvent using a two-stage defoliation process. Specifically, two vapor / liquid separators were used to pass the second bottom flow (from the second V / L separator) through a gear pump / pelletizer combination. DHT-4V® (hydrotalcite) [Clariant] was used as a passivator or acid scavenger in the continuous solution process. A slurry of DHT-4V in the process solvent was added before the first V / L separator.

[0359] Before pelletizing, the polyethylene composition was stabilized by adding approximately 500 ppm of IRGANOX1076 (primary antioxidant) and approximately 500 ppm of IRGAFOS168 (secondary antioxidant) based on the weight of the polyethylene composition. The antioxidants were dissolved in a process solvent and added between the first V / L separator and the second V / L separator.

[0360] Table 1 shows the reactor conditions used to produce Examples 1 to 6, which are polymer compositions of the present invention, and Examples 10, 11, 15, and 16, which are comparative polyethylene compositions.

[0361] Examples 1-6 and Comparative Examples 15 and 16 are ethylene-octene copolymers produced under similar conditions in a pilot plant. The production process utilized a double solution polymerization mode configured in series, using a single-site hafnocene catalyst (referred to as "metallocene" in the table) in the first reactor (R1) and a Ziegler-Natta catalyst (referred to as "Zn" in the table) in the second reactor (R2). Comparative Examples 15 and 16 had a melt flow ratio (I) greater than 60. 21 (Having / I2) (larger than the example of invention)

[0362] As can be seen from the table, Invention Examples 4-6 were manufactured using slightly different manufacturing conditions than Invention Example 3, demonstrating the robustness of product performance against changes in manufacturing conditions. This is important in commercial operation (facilitating process control and improving product quality).

[0363] Comparative Examples 10 and 11 were produced in the first reactor (R1) using a phosphine imine catalyst (referred to as "phosphine imine" in the table) instead of a hafnocene catalyst.

[0364] This specification also describes Comparative Examples 7-9 and 12-14.

[0365] Comparative Example 7: Commercially available rotational molding grade SURPASS® RMs245 (single-site catalyst, dual reactor AST technology), NOVA Chemicals. Comparative Example 8: Prepared substantially in accordance with U.S. Patent No. 9,321,865, Example 1. Comparative Example 9: Manufactured substantially in accordance with U.S. Patent No. 9,321,865, Example 3. Comparative Example 10: Prepared substantially in accordance with U.S. Patent No. 9,695,309, Example 73. Comparative Example 11: Prepared substantially in accordance with U.S. Patent No. 9,695,309, Example 71. Comparative Example 12: Manufactured substantially in accordance with U.S. Patent No. 2022 / 0396690, Example 1. Comparative Example 13: Prepared substantially in accordance with U.S. Patent No. 2022 / 0396690, Example 2. Comparative Example 14: Prepared substantially in accordance with Example 1, International Publication No. 2021 / 250520. This is a blend of two commercially available products, namely SURPASS RMs245 and CCs154. Comparative Example 15: Prepared substantially in accordance with Example 3 of International Publication No. 2022 / 195513. Comparative Example 16: Prepared substantially in accordance with Example 4 of International Publication No. 2022 / 195513.

[0366] Table 2 shows the properties of the polyethylene compositions of Invention Examples 1 to 6 and Comparative Examples 7 to 16.

[0367] As shown in Table 2, the CTREF profile of the inventive example is characterized by at least two peaks, specifically a first peak that elutes at temperatures above 95°C and a second peak that elutes at temperatures below 90°C. Figure 1 shows the temperature-ascending elution fractionation profiles obtained from REF-CEF for inventive examples 1 to 3 and comparative examples 7, 12, and 13.

[0368] Table 3 shows the main performance indicators in tests of plaques prepared from the exemplary polyethylene compositions and the rheological properties of the exemplary polyethylene compositions. In Invention Example 6, compared to Invention Examples 3-5, the melt flow index I2 (1.98 g / 10 min) is higher and the average molecular weight (M n M w M z It is noteworthy that the ESCR performance is maintained despite the low melt flow index I2 (since it is known that ESCR performance decreases when the melt flow index I2 is high or the molecular weight is low).

[0369] The results will be explained in more detail below, with reference to the figures.

[0370] [Table 1-1]

[0371] [Table 1-2]

[0372] [Table 2-1]

[0373] [Table 2-2]

[0374] [Table 2-3]

[0375] [Table 3-1]

[0376] [Table 3-2]

[0377] [Table 3-3]

[0378] <Estimation of zero-shear viscosity and rheological width parameters> Viscosity data can be fitted using the following Ellis model (Equation 7) and Carreau-Yasuda (CY) model (Equation 8).

number

[0379] In Equation 7, η(ω) is the complex viscosity as a function of angular frequency ω, C1 is the zero shear viscosity, C2 is the characteristic relaxation time, and C3 is the power exponent.

number

[0380] In Equation 8, η(ω) is the complex viscosity, C1 is the zero shear viscosity, C2 is the characteristic relaxation time, C3 is the transition width between the Newton plateau and the power law region, and C4 is the power law exponent. C3 is called the "rheological width parameter" or "parameter" in some literature and is proportional to the polydispersity index or the width of the molecular weight distribution. A steeper transition indicates a narrower molecular weight distribution.

[0381] <Dauleology Index (DRI)> The DRI estimates the deviation caused by the presence of long-chain branches in the zero-shear viscosity and the estimated characteristic relaxation time. For resins with a narrow molecular weight distribution and no long-chain branches, values close to zero are expected. When the molecular weight distribution of the material is narrow, high DRI values may be due to the presence of LCB.

[0382] Reference: S. Lai, T. A. Plumley, T. I. Butler, G. W. Knight, C. I. Kao, Dow Rheology Index (DRI) for Insite Technology Polyolefins (ITP): Unique Structure-Processing Relationships, ANTEC (San Francisco) May 1 - 5, 1994: 1814 - 1815.

[0383] <Relaxation Spectrum Index (RSI)> The chain mobility of polymer molecules can be characterized by the relaxation time spectrum. Union Carbide introduced the Relaxation Spectrum Index (RSI) based on the discrete relaxation spectrum. The RSI is sensitive to changes in molecular weight, molecular weight distribution, and long-chain branches.

[0384] Reference: M. Baumgaertel, H. H. Winter, Interrelation between continuous and discrete relaxation time spectra, Journal of Non-Newtonian Fluid Mechanics, 1992, Vol. 44: 15 - 36.

[0385] <GPC-FTIR Measurement Results> Figure 2 shows the molecular weight distribution and comonomer distribution by GPC-FTIR measurement. In graph A, Invention Examples 1 - 3 and Comparative Examples 15 and 16 are shown, and in graph B, Invention Example 3 and Comparative Examples 7 and 10 - 13 are shown.

[0386] The invention is characterized in that the high molecular weight component has a branching frequency of more than 2 per 1000 carbon atoms, and preferably more than 4 per 1000 carbon atoms.

[0387] <Results of rheological behavior> Figure 3 shows the results of the rheological behavior. Specifically, in Figure 3, graphs A, B, and C show the complex viscosity profiles obtained from DMA frequency sweeps at 190°C. On the other hand, graph D shows the relationship between zero shear viscosity (estimated using the Ellis model) and weight-average molecular weight, with labels indicating example numbers and dashed lines indicating the trend for each dataset.

[0388] Furthermore, the data was fitted using a rheological model, and various parameters were obtained. These parameters are summarized in Table 3 above.

[0389] The presence of long-chain branching in the examples produced using the hafnocene catalyst (Inventive Examples 1-6 and Comparative Examples 15 and 16) is most evident from the characteristic that the transition width between the Newton plateau and the power law region extends over a longer frequency range compared to resins with a linear molecular structure (i.e., resins without long-chain branching). The transition width is less pronounced in the inventive examples than in Comparative Examples 15 and 16 (which have a higher long-chain branching content). In this disclosure, this transition is quantified using the rheological width parameter a (Carreau-Yasuda model).

[0390] The relaxation spectral index (RSI) and Daureology index (DRI) values ​​also suggest the presence of long-chain branching in Examples 1-3, but the effect is not as pronounced as in Comparative Examples 15 and 16.

[0391] The inventive example contains a small amount of long-chain branching, and as a result, it has a linear structure and is considered to have a higher zero-shear viscosity and higher melt strength compared to a resin having an equivalent molecular weight distribution otherwise (see graph D in Figure 3). The presence of long-chain branching is indicated by a relatively low value of the rheology breadth parameter a (generally less than about 0.040). The high zero-shear viscosity (i.e., high flow resistance at low deformation frequencies) is advantageous in the manufacture of large rotational molding parts (such as large tanks) where the heating cycle is long and the resin has a high risk of reaching an excessive melt flow limit.

[0392] <ESCR, Izod Impact and Rigidity: Considerations and Results> Environmental stress cracking occurs when chemicals penetrate the material, resulting in a decrease in ductility and interference with the intermolecular forces that bind polymer chains. When the chemical penetrates, the energy required to unwind the entanglement of the polymer chains decreases, and the failure mechanism changes from yielding.

[0393] ESCR is an important property in applications that contain chemicals, from household uses (such as detergents) to many industrial uses (such as agriculture and chemistry), including containers (such as intermediate bulk containers). The ESCR performance of polyethylene resins with a density exceeding 0.940 g / cm 3 tends to decrease as the density increases, which increases the rigidity. An increase in the amount of the crystalline structure may further restrict the mobility of the chains associated with the amorphous region. However, in the case of resins with a high density, a decrease in the comonomer content leads to a decrease in the amount of tie molecules that connect the crystalline domains to each other. The concept of tie molecules is related to the resistance to crack generation because it causes a decrease in the mobility of the chains in the amorphous region, making it more difficult for the chain entanglement to unwind when the specimen is subjected to stress.

[0394] The concept of tie molecules is also related to the effects of energy transfer and dissipation when a test specimen is subjected to impact. Resistance to IZOD impact and tensile impact generally decreases as density (stiffness) increases compared to resins with other comparable properties. IZOD impact measures a resin's resistance to bending impact, while tensile impact measurements are performed at higher deformation rates, thus helping to further differentiate resins.

[0395] Figure 4 (and Table 3 above) shows a comparison of the ESCR and impact performance of Invention Examples 1-6 and several comparative examples. In Figure 4, Graph A shows the results under ESCR condition A100 (in IGEPAL CO-630), and Graph B shows the Izod impact, both plotted against the bending secant modulus (1%).

[0396] The high performance of the inventive examples is primarily explained by the high content of comonomers incorporated into the high molecular weight components of these polymer compositions. This follows general guidelines for improving ESCR and toughness, based on the concept of tie molecules. The formation of tie molecules is facilitated by a combination of increased molecular weight and increased comonomer incorporation.

[0397] Izod impact generally decreases as density (stiffness) increases compared to resins with equivalent other resin properties. A similar trend is observed between ESCR and stiffness within the density range of the rigid molding applications discussed herein. As shown in Figure 4, in the examples produced using hafnosene catalysts (Inventive Examples 1-6 and Comparative Examples 15 and 16), the Izod impact-to-stiffness relationship tends to shift to higher values.

[0398] The inventive example demonstrates a superior combination of ESCR, Izod impact value, and stiffness compared to the comparative examples. Generally, higher Izod impact performance is observed when stiffness is equivalent (see, for example, Comparative Examples 7, 13, and 14).

[0399] <Preparation of rotationally molded parts> The powdered polyethylene composition was converted into rotational molded parts using a rotational molding machine. Specifically, a Rotospeed RS160 available from Ferry Industries Inc. (Stow, Ohio, USA) was used. The Rotospeed has two arms that rotate about a central axis within a sealed oven. A plate is attached to each arm, and this plate rotates about an axis that is approximately perpendicular to the axis of rotation of the arm. Six cast aluminum molds are attached to each arm to produce hollow rotational molded parts in a cubic shape (i.e., 12.5 inches (31.8 cm) × 12.5 inches × 12.5 inches). The rotation of the arms was set at approximately 8 revolutions per minute (rpm), and the rotation of the plates was set at approximately 2 rpm. Using a polyethylene composition in powder form with a standard fill weight of approximately 3.7 kg, rotational molded parts with a nominal thickness of approximately 0.250 inches (0.64 cm) were produced. The powder used had a 35 US mesh size (opening 0.0197 inches (500 μm)). The temperature within the sealed oven was maintained at 560°F (293°C). The molds and their contents were heated within the oven for 18, 20, 22, 24, and 26 minutes so that the powder was fully densified. Then, before removing the parts from the molds, the molds were cooled using an air fan for approximately 30 minutes. After removing the plastic parts from the molds, the parts were kept at room temperature for at least 24 hours and then cut to collect specimens for subsequent testing. Specimens were collected from the molded parts to evaluate the density and to conduct an ARM impact test.

[0400] <ARM Impact Test> The ARM impact test was conducted in accordance with ASTM D5628 at a test temperature of -40°C. This test was based on the Low Temperature Impact Test version 4.0 (July 2003) of the Association of Rotational Molders International. The purpose of this test was to investigate the impact properties of rotationally molded parts. The ARM impact test specimens (5 inches x 5 inches, 12.7 cm x 12.7 cm) were cut from the sidewall of a cubic rotationally molded part. The specimens were thermally equilibrated in a refrigerated test laboratory maintained at -40°F ± 3.5°F (-40°C ± 2°C) for at least 24 hours prior to the impact test. The test method employed is commonly known as the Bruceton step method or up-and-down method. In this procedure, a specific dart height is set at which 50% of the specimen will break. In other words, the test of dropping darts onto the specimen was continued until at least 10 passes and 10 failures (failures) were obtained. Each fracture was characterized as either ductile or brittle fracture. Ductile fracture was characterized by the dart penetrating the specimen, the impact area stretching and thinning, and a thread-like hole remaining at the fracture point. Brittle fracture was evident when a crack formed in the specimen, the crack radiating outward from the fracture point, and the specimen stretching little to no at the fracture point. The "ARM ductility" was calculated using the following formula: 100% × [(number of ductile fractures) / (total number of fractures)].

[0401] The samples were subjected to impact testing using a drop impact testing machine. The available impact darts consisted of 10-pound (4.54 kg), 15-pound (6.80 kg), 20-pound (9.07 kg), or 30-pound (13.6 kg) darts. All impact darts featured a round dart tip with a diameter of 1.0 ± 0.005 inches (2.54 cm), transitioning into a lower cylindrical shaft (1.0 inch in diameter), with the lower cylindrical shaft (to the dart tip) measuring 4.5 inches (11.4 cm). The impact darts included an upper cylindrical shaft with a diameter of 2.0 inches (5.08 cm), the length of which varied depending on the desired weight of the dart. For example, for 10-pound or 20-pound darts, the length was 10.5 inches (26.7 cm) or 16.5 inches (41.9 cm), respectively. Preferably, the weight of the dart was selected so that the drop height was between 2.5 feet and 7.5 feet (0.8 m to 2.3 m). The test specimen was positioned in the impact testing machine so that the falling dart would strike the surface of the part that had been in contact with the mold (during molding). If the specimen did not break at a given height and weight, either the height or the weight was gradually increased until the part broke. If breakage occurred, the height or weight was decreased by the same amount, and this process was repeated. The "ARM mean fracture energy (ft·lb)" was calculated by multiplying the drop height (ft) by the nominal dart weight (lb). After impact, both the top and bottom surfaces of the test specimen were inspected for fracture. For the polyethylene compositions disclosed herein, ductile fracture was the preferred mode of fracture.

[0402] <Results of rotational molding processability and performance window> Good rotational molding performance is characterized by parts that possess both high average fracture energy (>100 ft.lb) and high ductility (>50%). Processability and process window are defined by the range of oven residence times that provide good performance when molding conditions (mold, part thickness, oven temperature) are constant.

[0403] Figure 5 shows the results of tests performed on rotationally molded specimens (the specimens were 1 / 4 inch thick and collected from test cubes rotationally molded at an oven temperature of 293°C (560°F). See above for details on the preparation of rotationally molded parts). In Figure 5, graphs A and B show the mean ARM impact fracture energy at -40°C, graphs C and D show the ductility at -40°C, and graphs E and F show the difference between the density and plaque density (ASTM D792-13) after rotational molding.

[0404] Examples 1-3 of the invention demonstrate a process window comparable to or better than that of commercially available rotational molding grades (Comparative Example 7). Examples 1-3 also exhibit a superior process window compared to Comparative Examples 15 and 16. This is thought to be due to the inventions having more favorable rheological properties (lower zero-shear viscosity). Lower zero-shear viscosity promotes neck growth (sintering) between powder particles during the melt densification process. Good sintering leads to the formation of smaller bubbles, which dissolve into the molten material at a faster rate. Faster sintering and bubble dissolution are crucial for ensuring that densification of the molten material is completed within the molding cycle. If densification of the molten material is not completed, bubbles remain in the molded part, acting as defects and leading to a decrease in mechanical performance.

[0405] The inventive example maintains good performance despite the presence of air bubbles in the molded part (short oven heating time). The presence of air bubbles is presumed when the density of the molded sample is much lower than the plaque density (ASTM D792-13). Interestingly, the disclosed example exhibits superior impact performance (average fracture energy and ductility) despite slower densification than Comparative Example 7. This result suggests that the inventive example can provide good toughness while tolerating a higher level of defects in the molded part.

[0406] In Invention Examples 1 and 2, the additive package formulation for rotational molding tests contained 384 ppm by weight of hydroxylamine, IRGASTAB FS 042. Invention Example 3 was formulated using two levels of IRGASTAB FS 042. As shown in the results for Invention Example 3 in Figure 5, the change in the additive package, specifically increasing the hydroxylamine content from 384 ppm by weight (labeled "standard additive") to 800 ppm by weight (labeled "alternative additive"), resulted in a significant improvement in performance and powder densification. This is shown in the average fracture energy, ductility, and density profiles against oven residence time in Figure 5. Significant changes were observed in achieving high ductility and fracture energy, as well as high densification.

[0407] Some additives were added in masterbatch form, while others were added in powder form. The masterbatch additives were melt-blended into Examples 1 and 2 using a Coperion ZSK26 twin-screw extruder. The additives were added to Example 3 using a Leistritz LSM 30.34 twin-screw extruder. Typical additive formulations were prepared by melt-blending the masterbatch additives. Alternative additive formulations used a combination of the masterbatch and selected additives (added in powder form). When adding powdered additives, the powder was first mixed with a portion of the base resin, also in powder form, to ensure accurate additive weight throughout the sample.

[0408] <Deconvolution of polyethylene compositions> For Invention Examples 1 to 6, mathematical deconvolution was performed to determine the relative amounts of the first and second ethylene copolymers (and the third ethylene copolymer if present in the comparative example) in the polyethylene composition, and the molecular weight (M) of each copolymer was determined. w M n M z The ), and comonomer content (SCB frequency per 1000 carbon atoms in the polymer skeleton) were determined. In the deconvolution calculations, it was assumed that the single-site catalyzed ethylene copolymer component followed the Flory molecular weight distribution function and had a uniform comonomer distribution across the entire molecular weight range. The ethylene copolymer component produced using the Ziegler-Natta catalyst was modeled as a combination of four catalyst sites, each catalyst site following the Flory molecular weight distribution function. The data shown in Table 4 for comparative examples (Examples 10 and 11) are the same as those previously reported in U.S. Patent No. 9695309.

[0409] The estimates were first obtained from predictions using a basic kinetic model with kinetic constants specific to each catalyst formulation, as well as the feedstock and reactor conditions. This simulation is based on the configuration of the solution pilot plant described above, which was used to produce the polyethylene compositions disclosed herein. Using the predictions of the kinetic model, estimates of the short-chain branching distribution in the first and second ethylene copolymer components were established. The estimates of the short-chain branching content were also validated against experimental results obtained from GPC-FTIR for the comonomer distribution. The fit between the simulated molecular weight distribution profiles and the actual data obtained from GPC chromatography was improved by modeling the molecular weight distribution as the sum of components having molecular weight distributions described using a multi-site idealized Flory distribution.

[0410] During deconvolution, the total Mn, Mw, and Mz are calculated using the following relationship: Mn = 1 / Σ(w i / (Mn) i ),Mw=Σ(w i x(Mw) i ), Mz=Σ(w i x(Mz) i 2 / Σ(w i x(Mz i In the formula, i represents the i-th component, and w i This represents the relative weight fraction of the i-th component in the composition.

[0411] The density and melt index I2 of each ethylene copolymer component were calculated using the following formula:

number

number

number

[0412] The results of molecular weight deconvolution are shown in Table 4. Table 4 shows Invention Examples 1 to 6 and Comparative Examples (10 and 11) with the closest compositions.

[0413] [Table 4] [Industrial applicability]

[0414] This paper presents a polyethylene composition suitable for use in rotationally molded plastic articles. When fabricated into plaque, the polyethylene composition exhibits a good combination of environmental stress crack resistance, IZOD impact strength, and rigidity.

Claims

1. A polyethylene composition, (i) 0.880-0.930g / cm ３ Density, molecular weight distribution of 1.7 to 2.7 (M ｗ / M ｎ ), and weight-average molecular weight (M) of 140,000 to 250,000 g / mol ｗ A first ethylene copolymer having 10 to 60 weight percent, (ii) 0.940-0.975g / cm ３ Density, molecular weight distribution of 2.0 to 3.3 (M ｗ / M ｎ ), and weight-average molecular weight (M) of 20,000 to 90,000 g / mol ｗ ) comprising 90 to 40 weight percent of a second ethylene copolymer and Includes, The ratio of the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer to the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer (SCB1 / SCB2) is at least 5.

0. The polyethylene composition has a density of at least 0.940 g / cm ３ , a melt index (I ２ ) of less than 3.0 g / 10 min, a melt flow ratio (I ２１ / I ２ ) of at most 60, and a long chain branching factor (LCBF) of at most 0.0400, and A polyethylene composition in which the weight percentage of the first or second ethylene copolymer is defined as the weight of the first or second ethylene copolymer divided by the total weight of the first and second ethylene copolymers and multiplied by 100%.

2. The polyethylene composition according to claim 1, wherein the polyethylene composition has an LCBF of 0.0050 to 0.0375.

3. The polyethylene composition has a melt flow ratio of 20 to 50 (I ２１ / I ２ A polyethylene composition according to claim 1 or 2, having the following characteristics:

4. The polyethylene composition has a molecular weight distribution of less than 4.5 (M ｗ / M ｎ A polyethylene composition according to any one of claims 1 to 3, having the following characteristics:

5. The polyethylene composition has a molecular weight distribution of 2.0 to 4.0 (M ｗ / M ｎ The polyethylene composition according to claim 4, having )

6. The polyethylene composition according to any one of claims 1 to 5, wherein the polyethylene composition has a unimodal profile in GPC analysis.

7. The density of the first ethylene copolymer is 0.890–0.925 g / cm³ ３ The polyethylene composition according to any one of claims 1 to 6.

8. Melt index of the first ethylene copolymer (I ２ The polyethylene composition according to any one of claims 1 to 7, wherein the maximum amount is 1.0 g / 10 min.

9. Melt index of the first ethylene copolymer (I ２ The polyethylene composition according to claim 8, wherein the amount is 0.001 to 0.7 g / 10 min.

10. Melt index of the second ethylene copolymer (I ２ The polyethylene composition according to any one of claims 1 to 9, wherein the amount is at least 2.0 g / 10 min.

11. Melt index of the second ethylene copolymer (I ２ The polyethylene composition according to claim 10, wherein the amount is 2.0 to 50 g / 10 min.

12. The polyethylene composition contains 0.942 to 0.957 g / cm³. ３ A polyethylene composition according to any one of claims 1 to 11, having the density of .

13. The polyethylene composition contains 0.945 to 0.955 g / cm³. ３ The polyethylene composition according to claim 12, having the density of .

14. The polyethylene composition has a melt index (I) of 1.0 to 2.6 g / 10 min. ２ A polyethylene composition according to any one of claims 1 to 13, having the following characteristics:

15. The polyethylene composition has a high-load melt index (I) of at least 30 g / 10 min. ２１ A polyethylene composition according to any one of claims 1 to 14, having the following characteristics:

16. The polyethylene composition has a high-load melt index (I) of 30 to 100 g / 10 min. ２１ The polyethylene composition according to claim 15, having )

17. The polyethylene composition has a weight-average molecular weight (M) of 70,000 to 120,000 g / mol. ｗ A polyethylene composition according to any one of claims 1 to 16, having the following characteristics:

18. The polyethylene composition has a number average molecular weight (M) of 20,000 to 40,000 g / mol. ｎ A polyethylene composition according to any one of claims 1 to 17, having the following characteristics:

19. The polyethylene composition has a Z-average molecular weight (M) of less than 400,000 g / mol. ｚ A polyethylene composition according to any one of claims 1 to 18, having the following characteristics:

20. The polyethylene composition has a Z-average molecular weight (M) of 100,000 to 350,000 g / mol. ｚ The polyethylene composition according to claim 19, having ).

21. Polyethylene composition has an M content of less than 3.3 ｚ / M ｗ A polyethylene composition according to any one of claims 1 to 20, having the following characteristics.

22. The polyethylene composition has an M content of 1.5 to 3.

0. ｚ / M ｗ The polyethylene composition according to claim 21, having the following characteristics.

23. The polyethylene composition according to any one of claims 1 to 22, wherein the polyethylene composition contains 0.0015 to 2.4 ppm of hafnium.

24. The polyethylene composition according to any one of claims 1 to 23, wherein the first ethylene copolymer has 2 to 30 short-chain branches (SCB1 / 1000C) per 1000 carbon atoms.

25. The polyethylene composition according to claim 24, wherein the first ethylene copolymer has 4 to 25 short-chain branches (SCB1 / 1000C) per 1000 carbon atoms.

26. The polyethylene composition according to any one of claims 1 to 25, wherein the second ethylene copolymer has 0.05 to 3 short-chain branches (SCB2 / 1000C) per 1000 carbon atoms.

27. The polyethylene composition according to any one of claims 1 to 26, wherein the ratio (SCB1 / SCB2) of the number of short-chain branches per 1,000 carbon atoms in the first ethylene copolymer to the number of short-chain branches per 1,000 carbon atoms in the second ethylene copolymer is at least 10.

28. The polyethylene composition according to any one of claims 1 to 27, wherein the polyethylene composition has a fraction that elutes at a temperature above 95°C in CTREF analysis.

29. The polyethylene composition according to any one of claims 1 to 28, wherein the polyethylene composition has a fraction that elutes at a temperature of less than 90°C in CTREF analysis.

30. The polyethylene composition according to any one of claims 1 to 29, wherein the rheological width parameter (a) measured by the Carreau-Yasuda model is less than 0.

400.

31. A polyethylene composition according to any one of claims 1 to 30, having an environmental stress crack resistance (ESCR) of more than 500 hours (determined by ASTM D1693 in 100% IGEPAL CO-630 under condition A).

32. The polyethylene composition according to claim 31, having an environmental stress crack resistance (ESCR) of more than 1,000 hours (determined by ASTM D1693 in 100% IGEPAL CO-630 under condition A).

33. A polyethylene composition according to any one of claims 1 to 32, having an environmental stress crack resistance (ESCR) of more than 50 hours (determined by ASTM D1693 in 10% IGEPAL CO-630 under condition A).

34. The polyethylene composition according to claim 33, having an environmental stress crack resistance (ESCR) of more than 100 hours (determined by ASTM D1693 in 10% IGEPAL CO-630 under condition A).

35. A polyethylene composition according to any one of claims 1 to 34, having an Izod impact value of at least 4.0 foot-pounds / inch.

36. The polyethylene composition according to claim 35, having an Izod impact value of 4.0 to 13.0 foot-pounds / inch.

37. The polyethylene composition according to claim 35 or 36, having an Izod impact value of at least 6.0 foot-pounds / inch.

38. At least 230 foot-pounds per inch ２ A polyethylene composition according to any one of claims 1 to 37, having a tensile impact value.

39. The polyethylene composition according to any one of claims 1 to 38, wherein the secant modulus of bending at 1% is at least 1000 MPa.

40. The polyethylene composition according to claim 39, wherein the secant modulus of bending at 1% is 1000 to 1300 MPa.

41. A polyethylene composition according to any one of claims 1 to 40, wherein the elastic ratio (G' / G'') at 0.05 rad / s is a maximum of 0.

25.

42. A solution-phase polymerization process for producing polyethylene compositions, The solution-phase polymerization process is A step of polymerizing ethylene and alpha-olefin using a metallocene catalyst in a first reactor, The process involves polymerizing ethylene and alpha-olefin using a Ziegler-Natta catalyst in a second reactor. Includes, The first reactor and the second reactor are configured in series with respect to each other. Polyethylene composition, (i) 0.880-0.930g / cm ３ Density, molecular weight distribution of 1.7 to 2.7 (M ｗ / M ｎ ), and weight-average molecular weight (M) of 140,000 to 250,000 g / mol ｗ A first ethylene copolymer having 10 to 60 weight percent, (ii) 0.940-0.975g / cm ３ Density, molecular weight distribution of 2.0 to 3.3 (M ｗ / M ｎ ), and weight-average molecular weight (M) of 20,000 to 90,000 g / mol ｗ ) comprising 90 to 40 weight percent of a second ethylene copolymer and Includes, The ratio of the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer to the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer (SCB1 / SCB2) is at least 5.

0. The polyethylene composition contains at least 0.940 g / cm³ ３ Density, melt index (I) less than 3.0 g / 10 min ２ ), with a maximum melt flow ratio of 60 (I ２１ / I ２ ), and having a long-chain branching coefficient (LCBF) of up to 0.0400, A solution-phase polymerization process in which the weight percentage of the first or second ethylene copolymer is defined as the weight of the first or second ethylene copolymer divided by the total weight of the first and second ethylene copolymers and multiplied by 100%.

43. A rotationally molded article prepared from a polyethylene composition, Polyethylene composition, (i) 0.880-0.930g / cm ３ Density, molecular weight distribution of 1.7 to 2.7 (M ｗ / M ｎ ), and weight-average molecular weight (M) of 140,000 to 250,000 g / mol ｗ A first ethylene copolymer having 10 to 60 weight percent, (ii) 0.940-0.975g / cm ３ Density, molecular weight distribution of 2.0 to 3.3 (M ｗ / M ｎ ), and weight-average molecular weight (M) of 20,000 to 90,000 g / mol ｗ ) comprising 90 to 40 weight percent of a second ethylene copolymer and Includes, The ratio of the number of short-chain branches per 1000 carbon atoms in the first ethylene copolymer to the number of short-chain branches per 1000 carbon atoms in the second ethylene copolymer (SCB1 / SCB2) is at least 5.

0. The polyethylene composition contains at least 0.940 g / cm³ ３ Density, melt index (I) less than 3.0 g / 10 min ２ ), with a maximum melt flow ratio of 60 (I ２１ / I ２ ), and having a long-chain branching coefficient (LCBF) of up to 0.0400, A rotationally molded article in which the weight percentage of the first or second ethylene copolymer is defined as the weight of the first or second ethylene copolymer divided by the total weight of the first and second ethylene copolymers and multiplied by 100%.

44. The rotational molded article according to claim 43, wherein the polyethylene composition contains an additive package comprising at least one additional additive selected from the group consisting of a hindered monophosphite, a diphosphite, a hindered amine light stabilizer, and hindered phenol and hydroxylamine.

45. The rotationally molded article according to claim 44, wherein the hydroxylamine in the additive package is N,N-dialkylhydroxylamine, preferably IRGASTAB FS042.

46. The rotationally molded article according to claim 45, wherein hydroxylamine is present at a concentration of at least about 750 ppm by weight.

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