阅读说明：本技术 基于聚乙烯的组合物和包含它们的薄膜和制品 (Polyethylene-based compositions and films and articles comprising the same ) 是由 A·T·海特斯彻 S·比斯瓦斯 M·B·卡普尔 A·威廉森 P·P·方丹 J·B·古贝特 于 2020-05-01 设计创作，主要内容包括：本发明提供适用于包装应用、膜和制品的基于聚乙烯的组合物。一方面,适用于包装应用的基于聚乙烯的组合物包含(a)基于基于聚乙烯的组合物的总重量,至少97％重量的聚乙烯组合物,所述聚乙烯组合物包含：(i)25-37重量％的密度为0.935-0.947g/cm～(3)且熔融指数(I-(2))小于0.1g/10分钟的第一聚乙烯级分；和(ii)63％至75重量％的第二聚乙烯级分；和(b)基于基于聚乙烯的组合物的总重量,90至540ppm的1,2-环己烷二甲酸的钙盐；其中当使用～(13)C NMR测量时,聚乙烯组合物每1,000个碳原子具有小于0.10个支链,其中所述基于聚乙烯的组合物的密度为至少0.965g/cm～(3),并且其中所述基于聚乙烯的组合物的熔融指数(I-(2))为0.5至10g/10分钟。(The present invention provides polyethylene-based compositions suitable for packaging applications, films, and articles. In one aspect, a polyethylene-based composition suitable for packaging applications comprises (a) at least 97% by weight, based on the total weight of the polyethylene-based composition, of a polyethylene composition comprising: (i)25-37 wt.% of a density of 0.935‑0.947g/cm 3 And melt index (I) 2 ) A first polyethylene fraction of less than 0.1g/10 min; and (ii) 63% to 75% by weight of a second polyethylene fraction; and (b) 90 to 540ppm, based on the total weight of the polyethylene-based composition, of a calcium salt of 1, 2-cyclohexanedicarboxylic acid; wherein when in use 13 The polyethylene composition has less than 0.10 branches per 1,000 carbon atoms as measured by C NMR, wherein the polyethylene-based composition has a density of at least 0.965g/cm 3 And wherein the melt index (I) of the polyethylene-based composition 2 ) Is 0.5 to 10g/10 min.)

1. A polyethylene-based composition suitable for packaging applications, the polyethylene-based composition comprising:

(a) at least 97% by weight, based on the total weight of the polyethylene-based composition, of a polyethylene composition comprising:

(i)25-37 wt% density of 0.935-0.947g/cm³And melt index (I)₂) A first polyethylene fraction of less than 0.1g/10 min; and

(ii) from 63% to 75% by weight of a second polyethylene fraction; and

(b) 90 to 540ppm, based on the total weight of the polyethylene-based composition, of a calcium salt of 1, 2-cyclohexanedicarboxylic acid;

wherein when in use¹³The polyethylene composition has less than 0.10 branches per 1,000 carbon atoms as measured by C NMRWherein the polyethylene-based composition has a density of at least 0.965g/cm³And wherein the melt index (I) of the polyethylene-based composition₂) Is 0.5 to 10g/10 min.

2. The polyethylene-based composition according to claim 1, wherein the polyethylene composition comprises from 25 to 37 weight percent of a polyethylene having a density in the range of from 0.940 to 0.947g/cm³In the range of from 63 to 75 wt% of said first polyethylene fraction and a density of 0.970g/cm³Or a larger fraction of said second polyethylene.

3. The polyethylene-based composition according to claim 1 or claim 2, wherein the polyethylene-based composition has a melt index (I)₂) Is 2.5g/10 minutes or less.

4. The polyethylene-based composition according to any one of the preceding claims, wherein the second polyethylene fraction has a melt index (I ™)₂) With the first polyethylene fraction, and a melt index (I)₂) Is at least 1,000.

5. The polyethylene-based composition according to any one of the preceding claims, wherein the polyethylene-based composition has a zero shear viscosity ratio of less than 2.0.

6. The polyethylene-based composition according to any one of the preceding claims, further comprising a fatty acid metal salt in an amount of 45 to 360ppm, based on the total weight of the composition.

7. The polyethylene-based composition according to any one of the preceding claims, further comprising silica in an amount of from 75 to 800ppm, based on the total weight of the composition.

8. The polyethylene-based composition according to any one of the preceding claims, wherein the polyethylene composition has less than 25 non-vinyl unsaturations per 100 ten thousand carbons.

9. A film comprising the polyethylene-based composition according to any one of the preceding claims.

10. An article comprising the polyethylene-based composition according to any one of claims 1-8.

Technical Field

The present invention relates to polyethylene-based compositions, films comprising such polyethylene-based compositions, and articles comprising such polyethylene-based compositions.

Introduction to

Some packages, such as food packages, are designed to protect the contents from the external environment and to promote extended shelf life. Such packages are typically constructed using barrier films having low Oxygen Transmission Rates (OTR) and Water Vapor Transmission Rates (WVTR). However, in balancing the barrier properties, package integrity is also considered, for example to avoid leakage.

For many years, the film industry has been working on reducing the water vapor transmission rate by various techniques. Some of which are described in, for example, U.S. Pat. Nos. 5,562,905, EP 0799274B 1, WO 01/70827 and WO2005/090464A 1. Other methods are described in U.S. patent No. 6,127,484 and WO 2004/000933a 1.

Previous literature work emphasizes the complex relationship between resin morphology, molecular properties, film manufacturing conditions, and the resulting water vapor barrier properties.

In addition to having good processability and other properties, it is also desirable to have new polyethylene resins that can provide improved water vapor barrier properties.

Disclosure of Invention

The present invention provides polyethylene-based compositions suitable for packaging applications, films, and articles. The polyethylene-based composition provides improved moisture barrier when incorporated into a film. In some embodiments, the polyethylene-based composition provides improved moisture barrier properties (reduced amount of water vapor passing through the film) when incorporated into the film, while also maintaining desirable physical properties. By being polyethylene-based, compositions according to some embodiments of the present invention may be incorporated into multilayer films and articles composed primarily (if not substantially or entirely) of polyolefins to provide films and articles that are more easily recyclable. In some embodiments, the polyethylene-based compositions of the present invention may be incorporated into the surface layer of the film and exhibit relatively low levels of dusting.

In one aspect, a polyethylene-based composition suitable for packaging applications comprises (a) at least 97% by weight, based on the total weight of the polyethylene-based composition, of a polyethylene composition comprising:

(i)25-37 wt% density of 0.935-0.947g/cm³And melt index (I)₂) A first polyethylene fraction of less than 0.1g/10 min; and

(ii) from 63% to 75% by weight of a second polyethylene fraction; and

(b) 90 to 540ppm of calcium 1, 2-cyclohexanedicarboxylate, based on the total weight of the polyethylene-based composition, where used¹³The polyethylene composition has less than 0.10 branches per 1,000 carbon atoms as measured by C NMR, wherein the polyethylene-based composition has a density of at least 0.965g/cm³And wherein the melt index (I) of the polyethylene-based composition₂) Is 0.5 to 10g/10 min. In some embodiments, the polyethylene composition comprises 25 to 37 weight percent of a polyethylene having a density in the range of 0.940 to 0.947g/cm³A first polyethylene fraction in the range and 63 to 75 wt.% of a density of 0.970g/cm³Or a higher second polyethylene fraction.

In another aspect, the present invention relates to a film comprising any of the polyethylene-based compositions disclosed herein.

In another aspect, the present invention relates to an article, such as a food package, comprising any of the laminates disclosed herein.

These and other embodiments are described in more detail in the detailed description.

Detailed Description

Unless stated to the contrary, implied by context, or customary in the art, all parts and percentages are by weight, all temperatures are in degrees celsius, and all test methods are current as of the filing date of this disclosure.

The term "composition" as used herein refers to a mixture comprising the materials of the composition as well as reaction products and decomposition products formed from the materials of the composition.

"Polymer" means a polymeric compound prepared by polymerizing monomers, whether of the same type or a different type. Thus, the generic term polymer encompasses the term homopolymer, as defined below, and the term interpolymer, as defined below. Trace impurities (e.g., catalyst residues) can be incorporated into and/or within the polymer. The polymer may be a single polymer, a blend of polymers, or a mixture of polymers, including a mixture of polymers formed in situ during polymerization.

The term "homopolymer" as used herein refers to a polymer prepared from only one type of monomer, it being understood that trace impurities may also be incorporated into the polymer structure.

As used herein, the term "interpolymer" refers to a polymer prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus encompasses both copolymers (used to refer to polymers prepared from two different types of monomers) and polymers prepared from more than two different types of monomers.

As used herein, the term "olefinic polymer" or "polyolefin" refers to a polymer that includes, in polymerized form, a majority amount of an olefin monomer, such as ethylene or propylene (by weight of the polymer), and optionally may include one or more comonomers.

As used herein, the term "ethylene/a-olefin interpolymer" is meant to comprise, in polymerized form, a majority amount of (a)>50 mol%) of units derived from ethylene monomer and the remaining units derived from one or more alpha-olefins. A typical alpha-olefin used to form the ethylene/alpha-olefin interpolymer is C₃-C₁₀An olefin.

As used herein, the term "ethylene/a-olefin copolymer" refers to a copolymer that includes, in polymerized form, a majority (>50 mol%) of ethylene monomer and a-olefin as the only two monomer types.

As used herein, the term "alpha-olefin" refers to an olefin having a double bond at the primary or alpha (alpha) position.

"polyethylene" or "ethylene-based polymer" shall mean a polymer comprising a majority (>50 mol%) of units derived from ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of polyethylene known in the art include: low Density Polyethylene (LDPE); linear Low Density Polyethylene (LLDPE); ultra Low Density Polyethylene (ULDPE); very Low Density Polyethylene (VLDPE); a single-site catalyzed linear low density polyethylene comprising both a linear low density resin and a substantially linear low density resin (m-LLDPE); ethylene-based thermoplastics (POP) and ethylene-based elastomers (POE); medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE). These polyethylene materials are generally known in the art, however, the following description may be helpful in understanding the differences between some of these different polyethylene resins.

The term "LDPE" may also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene" and is defined to mean that the polymer is partially or totally homo-or co-polymerized in autoclave or tubular reactors at pressures above 14,500psi (100MPa) using a free radical initiator such as a peroxide (see for example US 4,599,392, which is hereby incorporated by reference). The density of LDPE resins is generally in the range of from 0.916 to 0.935g/cm³Within the range of (1).

The term "LLDPE" includes both resins made using conventional Ziegler-Natta catalyst systems (Ziegler-Natta catalyst systems) and chromium-based catalyst systems as well as single-site catalysts, including but not limited to substituted mono-or biscyclopentadienyl catalysts (commonly referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts, and polyvalent aryloxyether catalysts (commonly referred to as bisphenylphenoxy), and includes linear, substantially linear, or heterogeneous polyethylene copolymers or homopolymers, LLDPE contains less long chain branching than LDPE and includes substantially linear ethylene polymers, which are further defined in U.S. Pat. No. 5,272,236, U.S. Pat. No. 5,278,272, U.S. Pat. No. 5,582,923, and U.S. Pat. No. 5,733,155, homogeneously branched linear ethylene polymer compositions, such as those in U.S. Pat. No. 3,645,992, heterogeneously branched ethylene polymers, such as those prepared according to the processes disclosed in U.S. patent No. 4,076,698; and/or blends thereof (such as those disclosed in US 3,914,342 or US 5,854,045). LLDPE can be made by gas phase, liquid phase or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

The term "MDPE" means a density of 0.926 to 0.935g/cm³The polyethylene of (1). "MDPE" is typically prepared using chromium or Ziegler-Natta catalysts or using single site catalysts, including but not limited to substituted mono-or bis-cyclopentadienyl catalysts (commonly referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts, and polyvalent catalyst aryloxyether catalysts (commonly referred to as bisphenylphenoxy), and typically has a molecular weight distribution ("MWD") greater than 2.5.

The term "HDPE" means a density greater than about 0.935g/cm³And up to about 0.980g/cm³Typically prepared with ziegler-natta catalysts, chromium catalysts or single site catalysts, including but not limited to substituted mono-or bis-cyclopentadienyl catalysts (commonly known as metallocenes), constrained geometry catalysts, phosphinimine catalysts and polyvalent catalyst aryloxyether catalysts (commonly known as bisphenylphenoxy).

The term "ULDPE" means a density of from 0.855 to 0.912g/cm³Typically prepared with ziegler-natta catalysts, chromium catalysts or single site catalysts, including but not limited to substituted mono-or bis-cyclopentadienyl catalysts (commonly referred to as metallocenes), constrained geometry catalysts, phosphinimine catalysts and multivalent catalysts (commonly referred to as bisphenylphenoxy). ULDPE includes, but is not limited to, polyethylene (ethylene-based) plastomers and polyethylene (ethylene-based) elastomers. Polyethylene (ethylene-based) elastomeric plastomers typically have a viscosity of from 0.855 to 0.912g/cm³The density of (c).

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

The terms "comprising", "including", "having" and derivatives thereof are not intended to exclude the presence of any additional component, step or procedure, whether or not the component, step or procedure is specifically disclosed. For the avoidance of any doubt, unless stated to the contrary, all compositions claimed through use of the term "comprising" may contain any additional additive, adjuvant or compound, whether polymeric or otherwise. In contrast, the term "consisting essentially of … …" excludes any other components, steps, or procedures from any subsequently recited range, except for those that are not essential to operability. The term "consisting of … …" excludes any component, step, or procedure not specifically recited or listed.

The present invention relates generally to polyethylene-based compositions suitable for packaging applications. When incorporated into films, the polyethylene-based compositions can reduce the water vapor transmission rate. Without wishing to be bound by theory, it is believed that the unique design of the polyethylene composition in combination with a specific amount of nucleating agent may provide improved barrier properties. The polyethylene-based compositions of the present invention can be incorporated into films and articles having improved barrier properties, particularly increased water vapor barrier properties. Because the compositions of the present invention are polyethylene-based, in some embodiments, the films and articles may be formed entirely or substantially entirely of polyolefins, making the films and articles easier to recycle.

In one aspect, a polyethylene-based composition suitable for packaging applications comprises (a) at least 97% by weight, based on the total weight of the polyethylene-based composition, of a polyethylene composition comprising:

(i)25-37 wt% density of 0.935-0.947g/cm³And melt index (I)₂) A first polyethylene fraction of less than 0.1g/10 min; and

(ii) from 63% to 75% by weight of a second polyethylene fraction; and

(b) 90 to 540ppm of calcium 1, 2-cyclohexanedicarboxylate, based on the total weight of the polyethylene-based composition, where used¹³The polyethylene composition has less than 0.10 branches per 1,000 carbon atoms as measured by C NMR, wherein the polyethylene-based composition has a density of at least 0.965g/cm³And wherein the melt index (I) of the polyethylene-based composition₂) Is 0.5 to 10g/10 min.

In some embodiments, the first polyethylene fraction has from 0.940 to 0.947g/cm³The density of (c). In some embodiments, the ethylene-based polymer has 0.970g/cm³Or a higher density. In some embodiments, the polyethylene composition comprises 25 to 37 weight percent of a polyethylene having a density in the range of 0.940 to 0.947g/cm³A first polyethylene fraction in the range and 63 to 75 wt.% of a density of 0.970g/cm³Or a higher second polyethylene fraction.

In some embodiments, the polyethylene composition comprises from 30 to 37 weight percent of the first polyethylene fraction.

In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes₂). In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes and to 10,000g/10 minutes or more₂). In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes and at most 10,000g/10 minutes₂). In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes and at most 1,000g/10 minutes₂). In some embodiments, the melt index (I) of the second polyethylene fraction₂) Melt index (I) with the first polyethylene fraction₂) Is at least 1,000.

In some embodiments, polyethylene-basedThe composition has a total melt index (I) of 2.5g/10 minutes or less₂)。

In some embodiments, the polyethylene-based composition has a zero shear viscosity ratio of less than 2.0.

In some embodiments, when used¹³The polyethylene composition has less than 0.05 branches/1,000 carbon atoms as measured by C NMR. In some embodiments, when used¹³The polyethylene composition has less than 0.03 branches/1,000 carbon atoms as measured by C NMR. In some embodiments, the polyethylene-based composition has less than 25 non-vinyl unsaturations per 100 million carbons. In some embodiments, the polyethylene-based composition has less than 20 non-vinyl unsaturations per 100 million carbons. In some embodiments, when used¹³The polyethylene composition has less than 0.05 branches per 1,000 carbon atoms and less than 20 non-vinyl unsaturations per 100 ten thousand carbons, as measured by C NMR.

In some embodiments, the polyethylene-based composition further comprises a fatty acid metal salt in an amount of 45 to 360ppm based on the total weight of the composition. The metal in the fatty acid metal salt is preferably zinc or magnesium. In some embodiments, the fatty acid metal salt is at least one of zinc stearate and zinc palmitate.

In some embodiments, the polyethylene-based composition further comprises silica in an amount of 75 to 800ppm, based on the total weight of the composition.

In some embodiments, when the polyethylene-based composition is incorporated into a monolayer film, the film exhibits a (g-mil)/(100 in) of 0.1 or less when measured according to ASTM F1249-06 at 38 ℃²Day) and 100% relative humidity.

In another aspect, the present invention relates to a film comprising any of the polyethylene-based compositions disclosed herein.

In another aspect, the present invention relates to an article, such as a food package, comprising any of the polyethylene-based compositions or films disclosed herein.

Polyethylene composition

As mentioned above, the polyethylene-based composition of the invention comprises a polyethylene composition comprising (i) from 25 to 37% by weight of a polyethylene having a density of from 0.935 to 0.947g/cm³Range and melt index (I)₂) A first polyethylene fraction of less than 0.1g/10 min; and (ii)63 to 75 wt% of a second polyethylene fraction, wherein when used¹³The polyethylene composition has less than 0.10 branches/1,000 carbon atoms as measured by C NMR, wherein the polyethylene-based composition has a density of at least 0.965g/cm³Wherein the melt index (I) of the polyethylene-based composition₂) Is 0.5 to 10g/10 min.

The polyethylene composition may comprise a combination of two or more embodiments as described herein.

In one embodiment, the polyethylene composition has at least 0.965g/cm³The density of (c). In some embodiments, the polyethylene composition has at least 0.968g/cm³The density of (c). In some embodiments, the polyethylene composition has at most 0.976g/cm³The density of (c). In some embodiments, the polyethylene composition has a density of from 0.965 to 0.976g/cm³E.g., 0.965 to 0.970, or 0.967 to 0.969, or 0.965 to 0.970g/cm³Density within the range. For example, the density may be 0.965 or 0.967g/cm³To a lower limit of 0.970, 0.972, 0.975 or 0.976g/cm³The upper limit of (3).

The polyethylene composition has a melt index (I) of 0.5 to 10g/10 min₂Or I2; at 190 deg.C/2.16 kg). For example, melt index (I)₂Or I2; at 190 ℃/2.16 kg) can be from a lower limit of 0.5, 0.7, 0.9, 1.0, 1.1, 1.2, 1.5, 2,3, 4, or 5g/10 minutes to an upper limit of 1.5, 2, 2.5, 3,4, 5,6, 7, 8, 9, or 10g/10 minutes. In some embodiments, the polyethylene composition has a melt index (I) of 0.5 to 5g/10 minutes, or 0.5 to 2.5g/10 minutes, or 0.7 to 3g/10 minutes, or 1.0 to 2.0g/10 minutes, or 1.0 to 1.5g/10 minutes₂)。

In some embodiments, the polyethylene composition has a melt index ratio (I) of 10 or greater₁₀/I₂). In some embodimentsThe polyethylene composition has a melt index ratio (I) of at most 17₁₀/I₂). In some embodiments, the polyethylene composition has a melt index ratio (I) of 10 to 17₁₀/I₂). In some embodiments, the polyethylene composition has a melt index ratio (I) of 12 to 17₁₀/I₂)。

The polyethylene composition has a low level of branching. In some embodiments, when used¹³The polyethylene composition has less than 0.10 branches per 1,000 carbon atoms as measured by C NMR. In some embodiments, when used¹³The polyethylene composition has less than 0.07 branches/1,000 carbon atoms as measured by C NMR. In some embodiments, when used¹³The polyethylene composition has less than 0.05 branches/1,000 carbon atoms as measured by C NMR. In some embodiments, when used¹³The polyethylene composition has less than 0.03 branches/1,000 carbon atoms as measured by C NMR.

In some embodiments, the polyethylene composition has a low level of non-vinyl unsaturation. In some embodiments, when used¹The polyethylene composition has less than 25 non-vinyl unsaturations per 100 ten thousand carbons as measured by H NMR. In some embodiments, when used¹The polyethylene composition has less than 20 non-vinyl unsaturations per 100 ten thousand carbons as measured by H NMR.

Without wishing to be bound by theory, it is believed that the combination of low branching levels and low levels of non-vinyl unsaturation in the polyethylene composition provides a greater amount of crystallinity in the polyethylene composition, thereby improving its barrier properties when formed into a film.

In one embodiment, the polyethylene composition has a ZSVR value of less than 2.0, or from 1.0 to 2.0, or from 1.2 to 1.8, or from 1.3 to 1.7.

In one embodiment, the polyethylene composition has a molecular weight distribution, expressed as the ratio of weight average molecular weight to number average molecular weight (M), in the range of from 8.0 to 14.0_w/M_n(ii) a By conv. GPC) e.g. molecular weight distribution (M)_w/M_n) May be from a lower limit of 8.0, 8.5, 9.0 or 9.5 to 10.0. An upper limit of 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, or 14.0. In some embodiments, M_w/M_nIs 10.0 to 12.0.

In one embodiment, the polyethylene composition has a number average molecular weight (M) in the range of 8,000 to 20,000 g/mole_n(ii) a As determined by conv. gpc). For example, the number average molecular weight can be from a lower limit of 8,000, 9,000, 10,000, or 11,000 grams/mole to an upper limit of 12,000, 13,000, 15,000, or 20,000 grams/mole.

In one embodiment, the polyethylene composition has a weight average molecular weight (M) in the range of 100,000 to 125,000 g/mole_w(ii) a As determined by conv. gpc). For example, the weight average molecular weight can be from a lower limit of 100,000, 105,000, or 110,000 grams/mole to an upper limit of 115,000, 120,000, or 124,000 grams/mole.

In one embodiment, the polyethylene composition has a z-average molecular weight (M) of at least 350,000 g/mole, for example, in the range of 350,000 to 600,000 g/mole_Z(ii) a Determined by conv. gpc). For example, the z-average molecular weight can be from a lower limit of 350,000, 375,000, 400,000, 405,000, or 410,000g/mol to an upper limit of 420,000, 425,000, 450,000, 475,000, 500,000, 550,000, or 600,000 g/mol.

In one embodiment, the polyethylene composition has an M of greater than 3.0_z/M_wRatios (each determined by conv. gpc). In some embodiments, the polyethylene composition has an M of greater than 3.5_z/M_wRatios (each determined by conv. gpc). In some embodiments, M_z/M_wMay be from 3.0 to 4.0, or in some embodiments from 3.5 to 4.5, or in some embodiments from 3.5 to 4.0.

In one embodiment, the polyethylene composition has a ZSVR less than 2.0 and an M greater than 3.0_z/M_wRatios (each determined by conv. gpc). In another embodiment, the polyethylene composition has a ZSVR less than 2.0 and an M greater than 3.5_z/M_wRatio (each by conv. gpc).

The polyethylene composition preferably comprises an ethylene-based polymer formed in the absence of a comonomer. In some embodiments, the polyethylene composition comprises at least 99 weight percent of the ethylene-based polymer formed in the absence of a comonomer. In some embodiments, the polyethylene composition comprises at least 99% by weight of a polymer comprising a majority (>99 mol%) of units derived from ethylene monomer.

The polyethylene composition used in the polyethylene-based composition of the invention comprises two fractions of polyethylene.

The first polyethylene fraction has a density of 0.935 to 0.947g/cm³The density of (c). In some embodiments, the first polyethylene fraction has from 0.940 to 0.947g/cm³The density of (c). The first polyethylene fraction has a melt index (I) of less than 0.1g/10 min₂). In some embodiments, the first polyethylene fraction has a melt index (I) of 0.01g/10 minutes or greater₂)_。In some embodiments, the first polyethylene fraction has a melt index of 0.05 to 0.1g/10 minutes. In some embodiments, when used¹³The first polyethylene fraction has less than 0.10 branches per 1,000 carbon atoms as measured by C NMR.

In some embodiments, the second polyethylene fraction has 0.970g/cm³Or a higher density. In some embodiments, the first polyethylene fraction has from 0.940 to 0.947g/cm³And the second polyethylene fraction has a density of 0.970g/cm³Or a greater density. In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes₂)_。In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes and at most 10,000g/10 minutes or more₂)_。In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes and at most 10,000g/10 minutes₂). In some embodiments, the second polyethylene fraction has a melt index (I) of at least 100g/10 minutes and at most 1,000g/10 minutes₂)。

In some embodiments, the melt index (I) of the second polyethylene fraction₂) And firstMelt index (I) of the polyethylene fraction₂) Is at least 1,000.

The polyethylene composition comprises from 25 to 37 wt% of the first polyethylene fraction and from 63 to 75 wt% of the second polyethylene fraction, based on the total weight of the polyethylene composition. In some embodiments, the polyethylene composition comprises from 30 to 37 weight percent of the first polyethylene fraction and from 63 to 70 weight percent of the second polyethylene fraction, based on the total weight of the polyethylene composition.

The polyethylene-based composition comprises at least 97 wt% of the polyethylene composition, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises up to 99 weight percent of the polyethylene composition, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises 97 to 98 weight percent of the polyethylene composition, based on the total weight of the polyethylene-based composition.

The following discussion focuses on the preparation of a first composition for use in embodiments of the present invention.

Polymerisation

Any conventional polymerization method may be employed to produce the polyethylene polymer. Such conventional polymerization processes include, but are not limited to, slurry polymerization processes, solution polymerization processes using one or more conventional reactors, such as loop reactors, isothermal reactors, stirred tank reactors, batch reactors, and/or any combination thereof, in parallel or in series. Polyethylene compositions can be produced, for example, via solution phase polymerization processes using one or more loop reactors, isothermal reactors, and combinations thereof.

Typically, the solution phase polymerization process is conducted at a temperature in the range of from 115 ℃ to 250 ℃ (e.g., from 115 ℃ to 200 ℃) and at a pressure in the range of from 300 to 1000psi (e.g., from 400 to 750psi) in one or more well-mixed reactors, such as one or more isothermal loop reactors or one or more adiabatic reactors. In one embodiment, in a dual reactor, the temperature in the first reactor is in the range of 115 to 190 ℃ (e.g., 115 to 175 ℃) and the second reactor temperature is in the range of 150 to 250 ℃ (e.g., 130 to 165 ℃). In another embodiment, the temperature in the reactor is in the range of 115 to 250 ℃ (e.g., 115 to 225 ℃) in a single reactor.

Residence times in solution phase polymerization processes are typically in the range of 2 to 30 minutes (e.g., 10 to 20 minutes). Ethylene, solvent, hydrogen, one or more catalyst systems, optionally one or more co-catalysts and optionally one or more co-monomers are continuously fed into one or more reactors. Exemplary solvents include, but are not limited to, isoparaffins. For example, such solvents are commercially available under the name ISOPAR E from ExxonMobil Chemical Co., Houston, Tex. The resulting mixture of polyethylene composition and solvent is then withdrawn from the reactor and the polyethylene composition is isolated. The solvent is typically recovered via a solvent recovery unit (i.e., a heat exchanger and a vapor liquid separator drum) and then recycled back into the polymerization system.

In one embodiment, the polyethylene polymer may be produced via solution polymerization in a dual reactor system (e.g., a double loop reactor system), wherein ethylene is polymerized in the presence of one or more catalyst systems. In some embodiments, only ethylene is polymerized. Additionally, one or more cocatalysts may be present. In another embodiment, the polyethylene composition may be produced by solution polymerization in a single reactor system, such as a single loop reactor system, wherein ethylene is polymerized in the presence of two catalyst systems. In some embodiments, only ethylene is polymerized.

Catalyst system

Specific embodiments of catalyst systems that may be used to produce the polyethylene compositions described herein will now be described. It should be understood that the catalyst system of the present disclosure may be embodied in different forms and should not be construed as limited to the particular embodiments set forth in the disclosure. Rather, embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art.

The term "independently selected" is used herein to indicate an R group (e.g., R)¹、R²、R³、R⁴And R⁵) May be the same or different (e.g., R)¹、R²、R³、R⁴And R⁵May each be substituted alkyl, or R¹And R²May be substituted alkyl and R³May be aryl, etc.). Use of the singular includes use of the plural and vice versa (e.g., a hexane solvent includes a plurality of hexanes). The named R group will generally have a structure recognized in the art as corresponding to the R group having the name. These definitions are intended to supplement and illustrate, but not to exclude, definitions known to those skilled in the art.

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

When used to describe certain chemical groups containing carbon atoms, the form is "(C)_x-C_y) By the insert expression "is meant that the unsubstituted form of the chemical group has from x carbon atoms to y carbon atoms, inclusive of x and y. For example, (C)₁-C₄₀) An alkyl group is an alkyl group having 1 to 40 carbon atoms in its unsubstituted form. In some embodiments and general structures, certain chemical groups may be substituted with one or more substituents (e.g., R)^S) And (4) substitution. Using the insert word "(C)_x-C_y) "defined R^SSubstituted versions of the chemical groups may contain more than y carbon atoms, depending on any group R^SThe identity of (c). For example, "exactly by one group R^SSubstituted (C)₁-C₄₀) Alkyl radical, wherein R^SIs phenyl (-C)₆H₅) "may contain 7 to 46 carbon atoms. Therefore, in general, when the insert word "(C) is used_x-C_y) "chemical groups defined by one or more substituents R containing carbon atoms^SWhen substituted, by adding both x and y to the substituents R from all carbon-containing atoms^SIs determined by the combined sum of the number of carbon atomsThe minimum and maximum total number of carbon atoms of the chemical group.

The term "substituted" means that at least one hydrogen atom (-H) bonded to a carbon atom or heteroatom corresponding to an unsubstituted compound or functional group is substituted (e.g., R)^S) And (6) replacing. The term "fully substituted" means that each hydrogen atom (H) bound to a carbon atom or heteroatom in the corresponding unsubstituted compound or functional group is substituted with a substituent (e.g., R)^S) And (6) replacing. The term "polysubstituted" means that at least two but less than all hydrogen atoms bound to a carbon atom or heteroatom in the corresponding unsubstituted compound or functional group are replaced by a substituent.

The term "-H" means a hydrogen or hydrogen group covalently bonded to another atom. "hydrogen" and "-H" are interchangeable and mean the same unless explicitly stated.

Term "(C)₁-C₄₀) The hydrocarbon group "means a hydrocarbon group of 1 to 40 carbon atoms, and the term" (C)₁-C₄₀) Hydrocarbylene "means a hydrocarbon diradical of 1 to 40 carbon atoms wherein each hydrocarbyl group and each hydrocarbon diradical is aromatic or non-aromatic, saturated or unsaturated, straight or branched chain, cyclic (including mono-and polycyclic, fused and non-fused polycyclic, including bicyclic; 3 carbon atoms or more) or acyclic and is unsubstituted or substituted by one or more R^SAnd (3) substituted.

In the present disclosure, (C)₁-C₄₀) The hydrocarbon group may be unsubstituted or substituted (C)₁-C₄₀) Alkyl, (C)₃-C₄₀) Cycloalkyl group, (C)₃-C₂₀) Cycloalkyl- (C)₁-C₂₀) Alkylene, (C)₆-C₄₀) Aryl, or (C)₆-C₂₀) Aryl radical- (C)₁-C₂₀) An alkylene group. In some embodiments, the foregoing (C)₁-C₄₀) Each of the hydrocarbyl groups independently has up to 20 carbon atoms (i.e., (C)₁-C₂₀) Hydrocarbyl), and other embodiments have up to 12 carbon atoms.

Term "(C)₁-C₄₀) Alkyl "and" (C)₁-C₁₈) Alkyl radicals "respectivelyMeans a saturated straight or branched chain hydrocarbon radical of 1 to 40 carbon atoms or 1 to 18 carbon atoms, which is unsubstituted or substituted by one or more RS. Unsubstituted (C)₁-C₄₀) Examples of alkyl are unsubstituted (C)₁-C₂₀) An alkyl group; unsubstituted (C)₁-C₁₀) An alkyl group; unsubstituted (C)₁-C₅) An alkyl group; a methyl group; an ethyl group; 1-propyl group; 2-propyl; 1-butyl; 2-butyl; 2-methylpropyl; 1, 1-dimethylethyl; 1-pentyl; 1-hexyl; 1-heptyl; 1-nonyl; and a 1-decyl group. Substituted (C)₁-C₄₀) Examples of alkyl groups are substituted (C)₁-C₂₀) Alkyl, substituted (C)₁-C₁₀) Alkyl, trifluoromethyl and [ C₄₅]An alkyl group. The term "[ C ]₄₅]Alkyl "(with square brackets) means that up to 45 carbon atoms are present in the group (including substituents) and is, for example, interrupted by one R^SSubstituted (C)₂₇-C₄₀) Alkyl radicals each of which is (C)₁-C₅) An alkyl group. Each (C)₁-C₅) The alkyl group may be methyl, trifluoromethyl, ethyl, 1-propyl, 1-methylethyl or 1, 1-dimethylethyl.

Term "(C)₆-C₄₀) Aryl "means unsubstituted or substituted (with one or more R) having 6 to 40 carbon atoms^SSubstituted) monocyclic, bicyclic or tricyclic aromatic hydrocarbon groups in which at least 6 to 14 carbon atoms are aromatic ring carbon atoms, and the monocyclic, bicyclic or tricyclic groups each include 1,2 or 3 rings; wherein 1 ring is aromatic, and 2 or 3 rings are independently fused or unfused and at least one of the 2 or 3 rings is aromatic. Unsubstituted (C)₆-C₄₀) Examples of aryl groups include: unsubstituted (C)₆-C₂₀) Aryl, unsubstituted (C)₆-C₁₈) An aryl group; 2- (C)₁-C₅) Alkyl-phenyl; 2, 4-bis (C)₁-C₅) Alkyl-phenyl; a phenyl group; a fluorenyl group; a tetrahydrofluorenyl group; a dicyclopentadiene acenyl group; hexahydro-dicyclopentadiene-o-phenyl; an indenyl group; a dihydroindenyl group; a naphthyl group; tetrahydronaphthyl; and phenanthrene. Substituted (C)₆-C₄₀) Aryl radicalsExample is substituted (C)₁-C₂₀) An aryl group; substituted (C)₆-C₁₈) An aryl group; 2, 4-bis ([ C ]₂₀]Alkyl) -phenyl; a polyfluorophenyl group; pentafluorophenyl; and fluoren-9-on-1-yl.

Term "(C)₃-C₄₀) Cycloalkyl "means a saturated cyclic hydrocarbon group of 3 to 40 carbon atoms, unsubstituted or substituted by one or more R^SAnd (4) substitution. Other cycloalkyl groups (e.g., (C)_x-C_y) Cycloalkyl) is defined in an analogous manner as having x to y carbon atoms and being unsubstituted or substituted by one or more R^SAnd (3) substituted. Unsubstituted (C)₃-C₄₀) Examples of cycloalkyl are unsubstituted (C)₃-C₂₀) Cycloalkyl, unsubstituted (C)₃-C₁₀) Cycloalkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Substituted (C)₃-C₄₀) Examples of cycloalkyl are substituted (C)₃-C₂₀) Cycloalkyl group, substituted (C)₃-C₁₀) Cycloalkyl, cyclopentanone-2-yl and 1-fluorocyclohexyl.

(C₁-C₄₀) Examples of the alkylene group include unsubstituted or substituted (C)₆-C₄₀) Arylene, (C)₃-C₄₀) Cycloalkylene and (C)₁-C₄₀) Alkylene (e.g., (C)₁-C₂₀) Alkylene). In some embodiments, the diradicals are on the same carbon atom (e.g., -CH)₂-) either on adjacent carbon atoms (i.e., a1, 2-diradical) or separated by one, two, or more than two intervening carbon atoms (e.g., respective 1, 3-diradicals, 1, 4-diradicals, etc.). Some diradicals include alpha, omega diradicals. An α, ω -diradical is a diradical having the greatest carbon backbone spacing between the carbons of the group. (C)₂-C₂₀) Some examples of alkylene alpha, omega-diyl include ethylene-1, 2-diyl (i.e., -CH)₂CH₂-), propan-1, 3-diyl (i.e., -CH₂CH₂CH₂-), 2-methylpropan-1, 3-diyl (i.e., -CH₂CH(CH₃)CH₂-)。(C₆-C₅₀) Some examples of arylene α, ω -diradicals includePhenyl-1, 4-diyl, naphthalene-2, 6-diyl or naphthalene-3, 7-diyl.

Term "(C)₁-C₄₀) Alkylene "means a saturated straight or branched chain diradical having 1 to 40 carbon atoms (i.e., the point of attachment of the group is not on a ring atom) that is unsubstituted or substituted with one or more R^SAnd (4) substitution. Unsubstituted (C)₁-C₅₀) Examples of alkylene are unsubstituted (C)₁-C₂₀) Alkylene radicals containing unsubstituted-CH₂CH₂-、-(CH₂)₃-、-(CH₂)₄-、-(CH₂)₅-、-(CH₂)₆-、-(CH₂)₇-、-(CH₂)₈-、-CH₂C*HCH₃And- (CH)₂)₄C*(H)(CH₃) Wherein "C" represents a carbon atom from which a hydrogen atom is removed to form a secondary or tertiary alkyl group. Substituted (C)₁-C₅₀) Examples of alkylene are substituted (C)₁-C₂₀) Alkylene, -CF₂-, -C (O) -and- (CH)₂)₁₄C(CH₃)₂(CH₂)₅- (i.e., 6-dimethyl-substituted n-1, 20-eicosene). Due to two R as mentioned previously^SCan be put together to form (C)₁-C₁₈) Alkylene radicals, thus substituted (C)₁-C₅₀) Examples of alkylene groups also include 1, 2-bis (methylene) cyclopentane, 1, 2-bis (methylene) cyclohexane, 2, 3-bis (methylene) -7, 7-dimethyl-bicyclo [2.2.1]Heptane and 2, 3-bis (methylene) bicyclo [2.2.2]Octane.

Term "(C)₃-C₄₀) Cycloalkylene "means unsubstituted or substituted with one or more R having from 3 to 40 carbon atoms^SSubstituted cyclic diradicals (i.e., groups on ring atoms).

The term "heteroatom" refers to an atom other than hydrogen or carbon. Examples of heteroatoms include O, S, S (O), S (O)₂、Si(R^C)₂、P(R^P)、N(R^N)、-N＝C(R^C)₂、-Ge(R^C)₂-or-Si (R)^C) -, wherein each R^CEach R^NAnd each R^PIs unsubstituted (C)₁-C₁₈) A hydrocarbyl group or-H. The term "heterohydrocarbon" refers to a molecule or molecular framework in which one or more carbon atoms are replaced with a heteroatom. Term "(C)₁-C₄₀) Heterohydrocarbyl "means a heterohydrocarbyl having 1 to 40 carbon atoms, and the term" (C)₁-C₄₀) Heterocarbylene "means a heterocarbyl diradical having 1 to 40 carbon atoms and one or more heteroatoms per heterohydrocarbon. The radical of the heterohydrocarbyl group is located on a carbon atom or a heteroatom, and the diradical of the heterohydrocarbyl group may be located: (1) on one or two carbon atoms, (2) one or two heteroatoms, or (3) on both carbon and heteroatoms. Each (C)₁-C₅₀) A heterohydrocarbyl radical and (C)₁-C₅₀) The heterohydrocarbylene group may be unsubstituted or may be substituted with (one or more R)^S) Substituted, aromatic or non-aromatic, saturated or unsaturated, linear or branched, cyclic (including monocyclic and polycyclic, fused and non-fused polycyclic) or acyclic.

(C₁-C₄₀) The heterohydrocarbyl group may be unsubstituted or substituted (C)₁-C₄₀) Heteroalkyl group, (C)₁-C₄₀) alkyl-O-, (C)₁-C₄₀) alkyl-S-, (C)₁-C₄₀) alkyl-S (O) -, (C)₁-C₄₀) alkyl-S (O)₂-、(C₁-C₄₀) hydrocarbyl-Si (R)^C)₂-、(C₁-C₄₀) hydrocarbyl-N (R)^N)-、(C₁-C₄₀) hydrocarbyl-P (R)^P)-、(C₂-C₄₀) Heterocycloalkyl group, (C)₂-C₁₉) Heterocycloalkyl- (C)₁-C₂₀) Alkylene, (C)₃-C₂₀) Cycloalkyl- (C)₁-C₁₉) Heteroalkylidene, (C)₂-C₁₉) Heterocycloalkyl- (C)₁-C₂₀) Heteroalkylidene, (C)₁-C₄₀) Heteroaryl, (C)₁-C₁₉) Heteroaryl- (C)₁-C₂₀) Alkylene, (C)₆-C₂₀) Aryl radical- (C)₁-C₁₉) A heteroalkylene group, or (C)₁-C₁₉) Heteroaryl radical-(C₁-C₂₀) A heteroalkylene group.

Term "(C)₄-C₄₀) Heteroaryl "means unsubstituted or substituted (with one or more R) with 4 to 40 total carbon atoms and 1 to 10 heteroatoms^SSubstituted) monocyclic, bicyclic or tricyclic heteroaromatic hydrocarbon groups, and the monocyclic, bicyclic or tricyclic groups contain 1,2 or 3 rings, respectively, wherein 2 or 3 rings are independently fused or non-fused, and at least one of the 2 or 3 rings is heteroaromatic. Other heteroaryl groups (e.g., (C)_x-C_y) Heteroaryl radicals are typically, e.g., (C)₄-C₁₂) Heteroaryl) is defined in an analogous manner as having x to y carbon atoms (e.g., 4 to 12 carbon atoms) and is unsubstituted or substituted with one or more than one R^SAnd (3) substituted. Monocyclic heteroaryl hydrocarbon groups are 5-or 6-membered rings. The 5 membered ring has 5 minus h carbon atoms, where h is the number of heteroatoms and can be 1,2 or 3; and each heteroatom may be O, S, N or P. Examples of the 5-membered heterocyclic aromatic hydrocarbon group are pyrrol-1-yl; pyrrol-2-yl; furan-3-yl; thiophen-2-yl; pyrazol-1-yl; isoxazol-2-yl; isothiazol-5-yl; imidazol-2-yl; oxazol-4-yl; thiazol-2-yl; 1,2, 4-triazol-1-yl; 1,3, 4-oxadiazol-2-yl; 1,3, 4-thiadiazol-2-yl; tetrazol-1-yl; tetrazol-2-yl; and tetrazol-5-yl. The 6 membered ring has 6 minus h carbon atoms, where h is the number of heteroatoms and can be 1 or 2, and the heteroatoms can be N or P. Examples of the 6-membered heterocyclic aromatic hydrocarbon group are pyridin-2-yl; pyrimidine-2-; and pyrazin-2-yl. Bicyclic heteroaromatic hydrocarbon groups may be fused 5, 6-or 6, 6-ring systems. Examples of fused 5, 6-ring system bicyclic heteroaromatic hydrocarbon groups are indol-1-yl; and benzimidazol-1-yl. Examples of fused 6, 6-ring system bicyclic heteroaromatic hydrocarbon radicals are quinolin-2-yl; and isoquinolin-1-yl. The tricyclic heteroaromatic hydrocarbon group may be a fused 5,6, 5-ring system; a 5,6, 6-ring system; a 6,5, 6-ring system; or a 6,6, 6-ring system. Examples of fused 5,6, 5-ring systems are 1, 7-dihydropyrrolo [3,2-f ]]Indol-1-yl. An example of a fused 5,6, 6-ring system is 1H-benzo [ f]Indol-1-yl. An example of a fused 6,5, 6-ring system is 9H-carbazol-9-yl. An example of a fused 6,5, 6-ring system is 9H-carbazol-9-yl. An example of a fused 6,6, 6-ring system is acridin-9-yl.

The aforementioned heteroalkyl group may be a heteroalkyl group containing (C)₁-C₅₀) Saturated straight or branched chain groups of carbon atoms, or fewer carbon atoms and one or more heteroatoms. Likewise, the heteroalkylene group can be a saturated straight or branched chain diradical containing 1 to 50 carbon atoms and one or more than one heteroatom. Heteroatoms as defined above may include Si (R)^C)₃、Ge(R^C)₃、Si(R^C)₂、Ge(R^C)₂、P(R^P)₂、P(R^P)、N(R^N)₂、N(R^N)、N、O、OR^C、S、SR^CS (O) and S (O)₂Wherein each of heteroalkyl and heteroalkylene is unsubstituted or substituted with one or more R^SAnd (4) substitution.

Unsubstituted (C)₂-C₄₀) Examples of heterocycloalkyl are unsubstituted (C)₂-C₂₀) Heterocycloalkyl, unsubstituted (C)₂-C₁₀) Heterocycloalkyl, aziridin-1-yl, oxetan-2-yl, tetrahydrofuran-3-yl, pyrrolidin-1-yl, tetrahydrothiophen-S, S-dioxido-2-yl, morpholin-4-yl, 1, 4-dioxan-2-yl, hexaazaphen-4-yl, 3-oxa-cyclooctyl, 5-thio-cyclononyl and 2-aza-cyclodecyl.

The term "halogen atom" or "halogen" means a group of fluorine atom (F), chlorine atom (Cl), bromine atom (Br) or iodine atom (I). The term "halide" means the anionic form of the following halogen atoms: fluoride ion (F)^-) Chloride ion (Cl)^-) Bromine ion (Br)^-) Or iodide ion (I)^-)。

The term "saturated" means free of carbon-carbon double bonds, carbon-carbon triple bonds, and (in heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus, and carbon-silicon double bonds. By one or more substituents R in saturated chemical groups^SIn the case of substitution, one or more double and/or triple bonds may or may not optionally be present in the substituent R^SIn (1). The term "unsaturated" means containing one or more carbon-carbon double bonds, carbon-carbon triple bonds and (in heteroatom-containing groups) carbon-nitrogen, carbon-phosphorus and carbon-silicon double bonds, excluding substituents R which may be present^SAny such double bond (if present) or that may be present in a (hetero) aromatic ring (if present).

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

in formula (I), M is a metal selected from titanium, zirconium or hafnium, said metal being in a formal oxidation state of +2, +3 or + 4; n is 0, 1 or 2; when n is 1, X is a monodentate ligand or a bidentate ligand; when n is 2, each X is a monodentate ligand and is the same or different; the metal-ligand complex is generally charge neutral; each Z is independently selected from-O-, -S-, -N (R)^N) -or-P (R)^P) -; l is (C)₁-C₄₀) Alkylene or (C)₁-C₄₀) A heterohydrocarbylene group of which (C)₁-C₄₀) A part of the alkylene group comprises a linker backbone of 1 to 10 carbon atoms connecting the two Z groups (bonded with L) in formula (I), or (C)₁-C₄₀) Part of the heterohydrocarbylene group comprises a linker backbone of 1 atom to 10 atoms linking the two Z groups in formula (I), wherein (C)₁-C₄₀) Each of the 1 to 10 atoms of the 1 atom to 10 atom linker backbone of the heterohydrocarbylene group is independently a carbon atom or a heteroatom, wherein each heteroatom is independently O, S, S (O), S (O)₂、Si(R^C)₂、Ge(R^C)₂、P(R^C) Or N (R)^C) Wherein each R is^CIndependently is (C)₁-C₃₀) Hydrocarbyl or (C)₁-C₃₀) A heterohydrocarbyl group; r¹And R⁸Independently selected from the group consisting of: -H, (C)₁-C₄₀) Hydrocarbyl radical, (C)₁-C₄₀) Heterohydrocarbyl, -Si (R)^C)₃、-Ge(R^C)₃、-P(R^P)₂、-N(R^N)₂、-OR^C、-SR^C、-NO₂、-CN、-CF₃、R^CS(O)-、R^CS(O)₂-、(R^C)₂C＝N-、R^CC(O)O-、R^COC(O)-、R^CC(O)N(R^N)-、(R^N)₂Nc (o) -, halogen and a group having formula (II), formula (III) or formula (IV):

in the formulae (II), (III) and (IV), R^31-35、R^41-48Or R^51-59Each of (A) is independently selected from (C)₁-C₄₀) Hydrocarbyl radical, (C)₁-C₄₀) Heterohydrocarbyl, -Si (R)^C)₃、-Ge(R^C)₃、-P(R^P)₂、-N(R^N)₂、-N＝CHR^C、-OR^C、-SR^C、-NO₂、-CN、-CF₃、R^CS(O)-、R^CS(O)₂-、(R^C)₂C＝N-、R^CC(O)O-、R^COC(O)-、R^CC(O)N(R^N)-、(R^N)₂NC (O) -, halogen or-H, with the proviso that R¹Or R⁸Is a group having formula (II), formula (III) or formula (IV).

In the formula (I), R^2-4、R^5-7And R^9-16Each of (A) is independently selected from (C)₁-C₄₀) Hydrocarbyl radical, (C)₁-C₄₀) Heterohydrocarbyl, -Si (R)^C)₃、-Ge(R^C)₃、-P(R^P)₂、-N(R^N)₂、-N＝CHR^C、-OR^C、-SR^C、-NO₂、-CN、-CF₃、R^CS(O)-、R^CS(O)₂-、(R^C)₂C＝N-、R^CC(O)O-、R^COC(O)-、R^CC(O)N(R^N)-、(R^C)₂NC (O) -, halogen and-H.

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

In an exemplary embodiment using a double loop reactor, the procatalyst used in the first loop is zirconium, [ [2, 2' "[ [ bis [ 1-methylethyl) germane]Bis (methyleneoxy-kappa O)]Bis [3 ", 5, 5" -tris (1, 1-dimethylethyl) -5' -octyl [1,1':3',1 "-terphenyl]-2'-olato-κO]](2-)]Dimethyl-having the formula C₈₆H₁₂₈F₂GeO₄Zr and the following structure:

in such an embodiment, the procatalyst used in the second loop is zirconium, [ [2, 2' "- [1, 3-propanediylbis (oxygen-. kappa.O) ]]Bis [3- [2, 7-bis (1, 1-dimethylethyl) -9H-carbazol-9-yl]]-5'- (dimethyloctylsilyl) -3' -methyl-5- (1,1,3, 3-tetramethylbutyl) [1,1 ]]-biphenyl]-2-olato-κO]](2-)]Dimethyl of formula C₁₀₇H₁₅₄N₂O₄Si₂Zr and the following structure:

cocatalyst component

The catalyst system comprising the metal-ligand complex of formula (I) may be rendered catalytically active by any technique known in the art for activating metal-based catalysts for olefin polymerization reactions. For example, a system comprising a metal-ligand complex of formula (I) can exhibit catalytic activity by contacting the complex with an activating cocatalyst or combining the complex with an activating cocatalyst. Suitable activating cocatalysts for use herein comprise an aluminum alkyl; polymeric or oligomeric aluminoxanes (also known as aluminoxanes); a neutral lewis acid; and non-polymeric, non-coordinating, ionic forms of compounds (including the use of such compounds under oxidizing conditions). A suitable activation technique is bulk electrolysis. Combinations of one or more of the foregoing activating cocatalysts and techniques are also contemplated. The term "alkylaluminum" means a monoalkylaluminum dihalide or monoalkylaluminum dihalide, a dialkylaluminum hydride or a dialkylaluminum halide or a trialkylaluminum. Examples of the polymeric or oligomeric aluminoxane include methylaluminoxane, methylaluminoxane modified with triisobutylaluminum, and isobutylaluminoxane.

The Lewis acid activator (cocatalyst) comprises a catalyst comprising 1 to 3 of (C) as described herein₁-C₂₀) A hydrocarbyl-substituted group 13 metal compound. In one embodiment, the group 13 metal compound is tris ((C)₁-C₂₀) Hydrocarbyl)) substituted aluminum or tris ((C)₁-C₂₀) Hydrocarbyl) -boron compounds. In other embodiments, the group 13 metal compound is a tri (hydrocarbyl) -substituted aluminum, tri ((C)₁-C₂₀) Hydrocarbyl-boron compound, tris ((C)₁-C₁₀) Alkyl) aluminum, tris ((C)₆-C₁₈) Aryl) boron compounds and halogenated (including perhalogenated) derivatives thereof. In other embodiments, the group 13 metal compound is tris (fluoro substituted phenyl) borane, tris (pentafluorophenyl) borane. In some embodiments, the activating cocatalyst is tris ((C)₁-C₂₀) Hydrocarbyl borates (e.g. trityl tetrafluoroborate) or tris ((C)₁-C₂₀) Hydrocarbyl) ammonium tetrakis ((C)₁-C₂₀) Hydrocarbyl) boranes (e.g., bis (octadecyl) methylammonium tetrakis (pentafluorophenyl) borane). As used herein, the term "ammonium" is intended as ((C)₁-C₂₀) Alkyl radical)₄N⁺、((C₁-C₂₀) Alkyl radical)₃N(H)⁺、((C₁-C₂₀) Alkyl radical)₂N(H)₂ ⁺、(C₁-C₂₀) Alkyl radicals N (H)₃ ⁺Or N (H)₄ ⁺Of each (C)₁-C₂₀) The hydrocarbyl groups (when two or more are present) may be the same or different.

The combination of neutral Lewis acid activators (co-catalysts) comprises a compound comprising tris ((C)₁-C₄) Alkyl) aluminum and tris ((C) halide₆-C₁₈) Aryl) boron compounds, especially tris (pentafluorophenyl) borane. Other embodiments are combinations of such neutral lewis acid mixtures with polymeric or oligomeric alumoxanes and combinations of a single neutral lewis acid, especially tris (pentafluorophenyl) borane, with polymeric or oligomeric alumoxanes. (Metal-ligand Complex) (Tris (pentafluoro-phenylborane): aluminoxane) [ e.g., (group 4 metal-ligand Complex) (Tris (pentafluoro-phenylborane): aluminoxane)]The ratio of moles is from 1:1:1 to 1:10:30, and in other embodiments from 1:1:1.5 to 1:5: 10.

The metal-ligand complex catalyst system comprising formula (I) can be activated to form an active catalyst composition by combination with one or more cocatalysts (e.g., a cation forming cocatalyst, a strong lewis acid, or a combination thereof). Suitable activating cocatalysts include polymeric or oligomeric aluminoxanes, especially methylaluminoxane, as well as inert, compatible, noncoordinating, ion forming compounds. Exemplary suitable cocatalysts include, but are not limited to: modified Methylaluminoxane (MMAO), bis (hydrogenated tallow alkyl) methyltetrakis (pentafluorophenyl) borate (1)^-) Amines, and combinations thereof.

In some embodiments, one or more of the foregoing activating cocatalysts are used in combination with each other. A particularly preferred combination is tris ((C)₁-C₄) Hydrocarbyl aluminum, tris ((C)₁-C₄) Hydrocarbyl) borane or ammonium borate with oligomeric or polymeric aluminoxane compounds. The ratio of the total moles of the one or more metal-ligand complexes of formula (I) to the total moles of the one or more activating cocatalysts in the activating cocatalysts is from 1:10,000 to 100: 1. In some embodiments, the ratio is at least 1:5000, in some other embodiments, at least 1: 1000; and 10:1 or less, and in some other embodiments, 1:1 or less. When aluminoxane is used alone as the activating cocatalyst, preferably, the number of moles of aluminoxane employed is at least 100 times the number of moles of the metal-ligand complex of formula (I). In some other embodiments, when tris (pentafluorophenyl) borane alone is used as the activating cocatalyst, the moles of tris (pentafluorophenyl) borane employed are the same as those of formula (I)The ratio of the total moles of the one or more metal-ligand complexes is 0.5:1 to 10:1, 1:1 to 6:1, or 1:1 to 5: 1. The remaining activating cocatalyst generally employed is in a molar amount approximately equal to the total molar amount of the one or more metal-ligand complexes of formula (I).

1, 2-Cyclohexanedicarboxylic acid calcium salt

The polyethylene-based composition of the invention further comprises a calcium salt of 1, 2-cyclohexanedicarboxylic acid. The calcium salt of 1, 2-cyclohexanedicarboxylic acid is a nucleating agent, which when used in appropriate amounts and in combination with the polyethylene compositions described herein, has been found to provide significant moisture barrier improvements (i.e., a reduction in the amount of moisture transported through the film) to films formed from the polyethylene-based compositions.

The amount of calcium 1, 2-cyclohexanedicarboxylate salt used in the polyethylene-based composition is important to provide the desired moisture barrier properties (i.e., a reduction in the amount of moisture transported through the film). The polyethylene-based composition comprises 90 to 540ppm of the calcium 1, 2-cyclohexanedicarboxylate salt, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises from 150 to 525ppm of the calcium salt of 1, 2-cyclohexanedicarboxylic acid, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises 165 to 495ppm of the calcium 1, 2-cyclohexanedicarboxylate salt, based on the total weight of the polyethylene-based composition.

In some embodiments, the calcium salt of 1, 2-cyclohexanedicarboxylic acid may be provided with a fatty acid metal salt, such as zinc stearate, zinc palmitate, and mixtures thereof. Some zinc palmitate may also be present based on the commercial preparation of zinc stearate, since commercial stearic acid typically contains a significant amount of palmitic acid. In some such embodiments, the polyethylene-based composition comprises 45 to 360ppm of at least one of zinc stearate and zinc palmitate, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises 50 to 275ppm of zinc stearate and/or zinc palmitate, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises from 85 to 255ppm of zinc stearate and/or zinc palmitate, based on the total weight of the polyethylene-based composition.

One non-limiting example of a calcium 1, 2-cyclohexanedicarboxylate salt that may be used in embodiments of the present invention is Hyperform HPN-20E from Milliken Chemical, Spartanburg, South Carolina. Hyperform HPN-20E contains 60-70 wt.% calcium 1, 2-cyclohexane dicarboxylate and 30-40 wt.% zinc stearate/palmitate. In some embodiments, the polyethylene-based composition comprises 150 to 800ppm of Hyperform HPN-20E, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises 250 to 750ppm of Hyperform HPN-20E, based on the total weight of the polyethylene-based composition.

In some embodiments, the calcium salt of 1, 2-cyclohexanedicarboxylic acid (and fatty acid metal salts (e.g., zinc stearate and/or zinc palmitate), when also included) may be provided as a masterbatch by blending it with a carrier resin prior to combination with the polyethylene composition described herein. In some such embodiments, the carrier resin is a resin having a melt index (I) of 4 to 12g/10 minutes₂) The polyethylene of (1). In some embodiments in which the calcium 1, 2-cyclohexanedicarboxylate salt and the zinc stearate/palmitate are provided as a masterbatch, the masterbatch comprises 2 to 4 weight percent of the calcium 1, 2-cyclohexanedicarboxylate salt and the zinc stearate/zinc palmitate, based on the total weight of the masterbatch. In one embodiment, the carrier resin is a resin having a density of 0.965 and a melt index (I) of 8 to 9g/10 minutes₂) A high density polyethylene homopolymer of narrow molecular weight distribution. In some embodiments, the masterbatch may also include other additives. Depending on the total amount of additives included, the masterbatch may include 85 to 98 wt% of a carrier resin, based on the total weight of the masterbatch.

Silicon dioxide

In some embodiments, the polyethylene composition further comprises silica. It has been found that when silica is used in appropriate amounts and in combination with the polyethylene compositions described herein, the level of dust in films formed from the polyethylene-based compositions can be reduced.

The amount of silica in the polyethylene-based composition is important to reduce the dust level when the polyethylene-based composition is incorporated into the surface layer of the film. In some embodiments, the polyethylene-based composition comprises 75 to 800ppm of silica, based on the total weight of the polyethylene-based composition. In some embodiments, the polyethylene-based composition comprises 100 to 500ppm of silica, based on the total weight of the polyethylene-based composition.

One non-limiting example of a silica useful in embodiments of the present invention is Sylobloc 45, commercially available from Grace Davison Company.

In some embodiments, talc may be used in addition to or as an alternative to silica.

In some embodiments, the silica may be provided as a masterbatch by blending with a carrier resin, calcium salt of 1, 2-cyclohexanedicarboxylic acid, and zinc stearate/palmitate prior to combination with the polyethylene composition described herein. The masterbatch may be as described above for the calcium salts of 1, 2-cyclohexanedicarboxylic acid and zinc stearate/palmitate. The amount of silica in the masterbatch can be based on the target silica of the overall polyethylene-based composition.

Film

In some embodiments, the invention relates to a film formed from any of the inventive polyethylene-based compositions as described herein.

The polyethylene-based composition provides improved moisture barrier when incorporated into a film. In some embodiments, when the polyethylene-based composition is incorporated into a monolayer film, the film exhibits a (g-mil)/(100 in) of 0.15 or less when measured according to ASTM F1249-06 at 38 ℃²Day) and 100% relative humidity. In some embodiments, when the polyethylene-based composition is incorporated into a monolayer film, the film exhibits a (g-mil)/(100 in) of 0.10 or less when measured according to ASTM F1249-06 at 38 ℃²Day) and 100% relative humidity.

In some embodiments, when incorporated into a surface layer of a monolayer film or a multilayer film, the film may exhibit a desired (i.e., low) level of dusting. Low levels of dust are advantageous in film manufacture and conversion of films to other articles. When the surface layer has a print, less dusting also helps to better maintain the print on the article.

In some embodiments of the multilayer film of the present invention, the multilayer film may comprise the polyethylene-based composition of the present invention in a surface layer and an inner layer. In some such embodiments, by using the same polyethylene-based composition in the surface layer and the inner layer, the multilayer film can be significantly simplified in terms of the number of different polymers incorporated in the multilayer film.

In some embodiments, the film is a blown film. In some embodiments, the film is a monolayer film. In some embodiments, the film is a multilayer film. Films may be formed from the polyethylene-based compositions of the present invention using methods and equipment well known to those skilled in the art.

The amount of polyethylene-based composition used in the film of the present invention may depend on a number of factors including, for example, whether the film is a monolayer film or a multilayer film, the other layers in the film (if a multilayer film), the barrier properties desired for the film, the end use of the film, and the like. In some embodiments where the film is a multilayer film, the polyethylene-based composition of the present invention may be provided in a single layer to provide barrier properties.

The films of the present invention can have a variety of thicknesses. The thickness of the blown film depends on many factors including, for example, whether the film is a monolayer film or a multilayer film, the other layers in the film (if a multilayer film), the desired properties of the film, the application in which the film is ultimately used, the equipment available for making the film, and the like. In some embodiments, the films of the present invention have a thickness of up to 10 mils. For example, the blown film can have a thickness with a lower limit of 0.25 mil, 0.5 mil, 0.7 mil, 1.0 mil, 1.75 mil, or 2.0 mil to an upper limit of 4.0 mil, 6.0 mil, 8.0 mil, or 10 mil.

In embodiments where the film comprises a multilayer film, the number of layers in the film may depend on a number of factors, including, for example, the desired properties of the film, the desired thickness of the film, the content of other layers of the film, the end use of the film, the equipment available for making the film, and the like. In various embodiments, the multilayer blown film may comprise up to 2,3, 4,5, 6, 7, 8, 9, 10, or 11 layers.

In some embodiments, the polyethylene-based composition of the present invention may be used in more than one layer of film. Other layers within the multilayer films of the present invention may comprise, in various embodiments, a polymer selected from the group consisting of: the composition of the present invention, LLDPE, VLDPE (very low density polyethylene), MDPE, LDPE, HDPE, HMWHDPE (high molecular weight HDPE), propylene-based polymers, polyolefin plastomer (POP), polyolefin elastomer (POE), Olefin Block Copolymer (OBC), ethylene vinyl acetate, ethylene acrylic acid, ethylene methacrylic acid, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene butyl acrylate, isobutylene, maleic anhydride grafted polyolefin, ionomers of any of the foregoing, or combinations thereof. In some embodiments, the multilayer films of the present invention may comprise one or more tie layers known to those skilled in the art.

It is to be understood that any of the foregoing layers may further include one or more additives known to those skilled in the art, such as antioxidants, ultraviolet stabilizers, thermal stabilizers, slip agents, antiblock agents, pigments or colorants, processing aids, crosslinking catalysts, flame retardants, fillers, and blowing agents. In some embodiments, the polyethylene-based composition comprises up to 3 weight percent of such additional additives. All individual values and subranges from 0 to 3 weight percent are included herein and disclosed herein; for example, the total amount of additives in the polymer blend can be from a lower limit of 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5 weight percent to an upper limit of 1,2, 3,4, or 5 weight percent.

By being polyethylene-based, according to some embodiments of the present invention, the polyethylene-based compositions of the present invention can be incorporated into multilayer films and articles that are primarily (if not substantially or entirely) composed of polyolefins to provide films and more easily recyclable articles. The polyethylene-based polymer of the present invention is particularly advantageous in verifying films in which the film is formed mainly of polyolefins such as polypropylene and/or polyethylene. For example, coated films in which the film comprises primarily polyethylene or polypropylene have improved recyclability characteristics, as well as other advantages that may be provided by the use of such polymers. In some embodiments, the film comprises 95 wt% or more polyethylene, based on the total weight of the film. In other embodiments, the film comprises 96 wt% or more, 97 wt% or more, 98 wt% or more, or 99 wt% or more polyethylene, based on the total weight of the film.

In some embodiments, a film comprising a layer formed from the polyethylene-based composition of the present invention may be laminated to another film.

In some embodiments, the films of the present invention may be corona treated and/or printed (e.g., reverse or surface printed) using techniques known to those skilled in the art.

In some embodiments, the films of the present invention may be oriented uniaxially (e.g., in the machine direction) or biaxially using techniques known to those skilled in the art.

Article of manufacture

Embodiments of the present invention also relate to articles, such as packaging, formed from or incorporated into the polyethylene-based compositions of the present invention (or films comprising the polyethylene-based compositions of the present invention). Such packages may be formed from any of the inventive polyethylene-based compositions (or films incorporating the inventive polyethylene-based compositions) described herein. The polyethylene-based composition of the invention is particularly suitable for articles requiring high water vapor barrier properties.

Examples of such articles may include flexible packaging, pouches, stand-up pouches, and pre-made packaging or pouches. In some embodiments, the multilayer film or laminate of the present invention may be used in food packaging. Examples of food products that may be included in such packages include meats, cheeses, grains, nuts, juices, sauces, and the like. Based on the teachings herein and based on the particular use of the package (e.g., type of food product, amount of food product, etc.), such packages can be formed using techniques known to those skilled in the art.

Test method

Unless otherwise indicated herein, the following analytical methods are used to describe various aspects of the present invention:

melt index

Melt index I₂(or I2) and I₁₀(or I10) measured at 190 ℃ and under loads of 2.16kg and 10kg, respectively, according to ASTM D-1238. The values are reported in g/10 minutes.

Density of

Samples for density measurement were prepared according to ASTM D4703. Method B measurements were made within one hour of pressing the sample according to ASTM D792.

Water vapor transmission rate

The WVTR of the films was measured according to ASTM F1249-06 with Mocon W3/33 at 38 ℃, 100% relative humidity and a thickness of about 50 microns.

Conventional gel permeation chromatography (conv. GPC)

The GPC-IR high temperature chromatography system from PolymerChar (Valencia, Spain) was equipped with a precision detector (Amherst, MA), a 2-angle laser light scattering detector model 2040, an IR5 infrared detector, and a 4-capillary viscometer (both from PolymerChar). Data collection was performed using PolymerChar Instrument Control software and a data collection interface. The system was equipped with an on-line solvent degassing apparatus from Agilent Technologies (Santa Clara, CA) and a pumping system.

The injection temperature was controlled at 150 ℃. The columns used were three 10 micron "hybrid B" columns from polymer laboratories (Shropshire, UK). The solvent used is 1,2, 4-trichlorobenzene. Samples were prepared at a concentration of "0.1 g polymer in 50ml solvent". The chromatographic solvent and sample preparation solvent each contained "200 ppm of Butylated Hydroxytoluene (BHT). "both solvent sources were sparged with nitrogen. The ethylene-based polymer sample was gently stirred at 160 degrees celsius for three hours. The injection volume was "200 microliters" and the flow rate was "1 milliliter/minute. The "GPC column set was calibrated by running 21" narrow molecular weight distribution "polystyrene standards. The Molecular Weight (MW) of the standards ranged from 580 to 8,400,000g/mol, and the standards were included in six "cocktail" mixtures. Each standard mixture has at least ten degrees of separation between the individual molecular weights. The standard mixtures were purchased from the polymer laboratory. The polystyrene standards were prepared as follows: for molecular weights equal to or greater than 1,000,000g/mol, 0.025g in 50mL solvent, and for molecular weights less than 1,000,000g/mol, 0.050g in 50mL solvent.

The polystyrene standards were dissolved at 80 ℃ for 30 minutes with gentle stirring. Narrow standard mixtures were run first and the descending order of the highest molecular weight components was followed to minimize degradation. The polystyrene standard peak molecular weight was converted to polyethylene molecular weight using equation 1 (described by Williams and Ward, j.polym.sci., polym.letters,6,621 (1968)):

m polyethylene ═ A × (M polystyrene)^B(equation 1) of the reaction mixture,

where M is the molecular weight, A equals 0.4316 and B equals 1.0.

The number average molecular weight (Mn (conv gpc)), the weight average molecular weight (Mw-conv gpc), and the z average molecular weight (Mz (conv gpc)) were calculated according to the following equations 2 to 4.

In equations 2-4, RV is the column retention volume (linear interval), collected at "1 Point per second," IR is the baseline-subtracted IR detector signal in volts from the IR5 measurement channel of the GPC instrument, and M_PEIs the polyethylene equivalent MW as determined by equation 1. Data calculations were performed using "GPC One software (version 2.013H)" from PolymerChar.

Creep zero-shear viscosity measurement method

Zero shear viscosity was obtained by creep testing on an AR G2 stress control rheometer (TA Instruments; New Castle, Del.) using "25 mm diameter" parallel plates at 190 ℃. The rheometer oven was set to the test temperature for at least 30 minutes before the fixture was zeroed. The compression molded sample pan was inserted between the plates at the test temperature and allowed to equilibrate for five minutes. The upper plate was then lowered to 50 μm (instrument setup) above the desired test gap (1.5 mm). Any excess material is trimmed away and the upper plate is lowered to the desired gap. The measurement was carried out at a flow rate of 5L/min under a nitrogen purge. The default creep time is set to two hours. Each sample was compression molded into a "2 mm thick x25 mm diameter" circular plate at 177 ℃ in air at a pressure of 10MPa over a period of 5 minutes. The sample was then removed from the press and placed on a counter to cool.

A constant low shear stress of 20Pa was applied to all samples to ensure that the steady state shear rate was low enough to be in the newton regime. For the samples in this study, the resulting steady state shear rate was 10^-3To 10^-4s^-1Within the range of (1). Steady state was determined by linear regression of all data in the last 10% time window of the plot of "log (J (t)) versus log (t)", where J (t) is creep compliance and t is creep time. If the slope of the linear regression is greater than 0.97, then steady state is considered to be reached and the creep test is stopped. In all cases of the study, the slope meets the criteria within one hour. The steady state shear rate is determined by the slope of the linear regression of all data points in the last 10% time window of the plot of "ε vs. t", where ε is the strain. The zero shear viscosity is determined by the ratio of the applied stress to the steady state shear rate.

To determine whether a sample degrades during a creep test, the same sample is subjected to a small amplitude oscillatory shear test from 0.1 to 100rad/s before and after the creep test. The complex viscosity values of the two tests were compared. If the difference in viscosity values is greater than 5% at 0.1rad/s, the sample is considered to have degraded during the creep test and the results are discarded.

Zero Shear Viscosity Ratio (ZSVR)

ZSVR is defined as the ratio of the Zero Shear Viscosity (ZSV) of a branched polyethylene material to the ZSV of a linear polyethylene material at an equivalent average molecular weight. According to the equation:

ZSVR＝η_0B/η_0L＝η_0B/(2.29^-15 X Mwt^3.65)

the ZSV value was obtained from the creep test at 190 ℃ by the method described above. As described above, Mwt was determined using conventional gel permeation chromatography. A correlation between the ZSV of a linear polyethylene and its mw (conv gpc) was established based on a series of linear polyethylene reference materials. Lower ZSVR indicates lower levels of long chain branching.

Use of¹³C NMR for branching measurements

Sample preparation

By mixing about 2.7g of a mixture containing 0.025M Cr (AcAc) in a Norell 1001-710 mm NMR tube₃To 0.20 to 0.30g of a sample was added 50/50 mixture of tetrachloroethane-d 2/o-dichlorobenzene to prepare a sample. Oxygen was removed by purging the tube with N2 for 1 minute. The sample was dissolved and homogenized by heating the tube and its contents to 120 ℃ - & 140 ℃ using a heating block and vortex mixer. Each sample was visually inspected to ensure homogeneity. The thoroughly mixed sample is not allowed to cool before inserting the heated NMR sample converter and/or NMR probe.

Data acquisition parameters

Data were collected using a Bruker 600MHz spectrometer equipped with a Bruker 10mm multinuclear high temperature CryoProbe. Data were acquired with a sample temperature of 120 ℃ using 1280 transients, 7.8 second pulse repetition delay, 90 degree flip angle, and reverse gating decoupling per data file. All measurements were performed on non-spinning samples in locked mode. The samples were thermally equilibrated and data was collected.¹³The C NMR chemical shifts are internally referenced to the EEE triad at 30.0 ppm. The data is processed into spectra, the appropriate peaks are integrated (branching quantified), and then one or more peak integrals are used or the total branching/1000C is averaged. If no branching is detected, the detection limit of the spectrum is calculated using, for example, the integration of peaks due to chain ends and the signal-to-noise ratio.

Use of¹H NMR measurement of unsaturation

The stock solution (3.26g) was added to 0.10 to 0.13g of polymer sample in a 10mm NMR tube. The stock solution is tetrachloroethane-d₂(TCE) and perchloroethylene (50:50, w: w) with 0.001M Cr³⁺Or 100% TCE and 0.001M Cr³⁺A mixture of (a). With N₂The solution in the tube was purged for 5 minutes to reduce the amount of oxygen. The sample was dissolved at 120 to 140 ℃ by periodic vortex mixing. Each time¹H NMR analysis was performed on a Bruker AVANCE 600MHz spectrometer with a 10mm cryoprobe at 120 ℃.

Two experiments were performed to measure unsaturation: one control and one double presaturation experiment. For the control experiment, the data were processed with an exponential window function for 0.7Hz line broadening. The residual 1H signal from TCE was set to 100 and the integral (Iotal) of about-0.5 ppm to 3ppm was used as the signal for the entire polymer in the control experiment. The total carbon number NC in the polymer is calculated as equation 1A below:

NC＝I_{total of}2 (equation 1A),

for the double pre-saturation experiment, the data was processed with an exponential window function with 0.7Hz line broadening and baseline was corrected from about 7ppm to 4 ppm. Residue from TCE¹The signal of H is set to 100 and the corresponding integral of the degree of unsaturation (I)_{Vinylidene radical}、I_{Trisubstituted}、I_{Vinyl radical}And I_{Vinylidene radical}) Integration is performed. It is well known that NMR spectroscopy can be used to determine polyethylene unsaturation, for example, as described in Busico, V. et al, Macromolecules (Macromolecules), 2005, volume 38, page 6989. The number of unsaturated units of vinylidene, trisubstituted, vinyl and vinylidene is calculated as follows:

N_{vinylidene radical}＝I_{Vinylidene radical}2 (equation 2A),

N_{trisubstituted}＝I_{Trisubstituted}(equation 3A) of the process,

N_{vinyl radical}＝I_{Vinyl radical}2 (equation 4A),

N_{vinylidene radical}＝I_{Vinylidene radical}/2 (equation 5A).

The units of unsaturation per 1,000 total carbons (i.e., all polymer carbons including backbone and branch) are calculated as follows:

N_{vinylidene radical}/1,000C＝(N_{Vinylidene radical}NC) 1,000 (equation 6A),

N_{trisubstituted}/1,000C＝(N_{Trisubstituted}NC) 1,000 (equation 7A),

N_{vinyl radical}/1,000C＝(N_{Vinyl radical}/NCH₂) 1,000 (equation 8A),

N_{vinylidene radical}/1,000C＝(N_{Vinylidene radical}/NC) 1,000 (equation 9A).

For residual protons from TCE-d2¹H signal, chemical shift reference set to 6.0 ppm. Control runs with ZG pulses, NS-16, DS-2, AQ-1.82 s, D1-14 s (where D1 is the relaxation delay). The double pre-saturation experiment was run with a modified pulse sequence where O1P-1.354 ppm, O2P-0.960 ppm, NS-50, AQ-1.82 s, D1-1 s (where D1 is the pre-saturation time), and D13-13 s (where D13 is the relaxation delay).

Some embodiments of the present invention will now be described in detail in the following examples.

Examples

Polyethylene composition 1

Embodiments of the polyethylene-based composition of the invention described in the following examples use polyethylene composition 1 and polyethylene composition 2. Polyethylene composition 1 was prepared according to the following process and based on the reaction conditions reported in table 1.

All of the feed (ethylene monomer) and process solvents (narrow boiling range high purity isoparaffin solvent, ISOPAR-E) are purified with molecular sieves prior to introduction to the reaction environment. Hydrogen is supplied pressurized at high purity levels and without further purification. The reactor monomer feed stream is pressurized via a mechanical compressor to greater than the reaction pressure. The solvent feed is pressurized via a pump to above the reaction pressure. Each catalyst component was manually batch diluted with purified solvent to the specified component concentration and pressurized above the reaction pressure. All reaction feed streams were measured with mass flow meters and independently controlled with a computer automated valve control system.

The continuous solution polymerization reactor consists of two liquid-filled non-adiabatic isothermal circulating loop reactors mimicking a Continuous Stirred Tank Reactor (CSTR) with heat removal. All fresh solvent, monomer, hydrogen and catalyst component feeds to each reactor can be independently controlled. The temperature of all fresh feed streams (solvent, monomer and hydrogen) entering each reactor is controlled by passing the feed streams through a heat exchanger. The total fresh feed to each polymerization reactor was injected into the reactor at two locations with approximately equal reactor volumes between each injection location. Fresh feed to the first reactor is typically controlled with each injector receiving half of the total fresh feed mass flow. The fresh feed to the second reactor in series is typically controlled to maintain half the total ethylene mass flow near each injector, and since unreacted ethylene from the first reactor enters the second reactor adjacent to the low pressure fresh feed, the injector typically has less than half the total fresh feed mass flow into the second reactor.

The catalyst/cocatalyst component of each reactor was injected into the polymerization reactor through a specially designed injection plug. Each catalyst/co-catalyst component was injected separately into the reactor at the same relative location with no contact time prior to the reactor. The computer controls the main catalyst component to maintain the individual reactor monomer conversion at a specified target. The co-catalyst component is fed based on the calculated specified molar ratio to the main catalyst component.

The catalyst used in the first reactor was zirconium, [ [2, 2' - [ [ bis [ 1-methylethyl) germanene]Bis (methyleneoxy-kappa O)]Bis [3 ", 5, 5" -tris (1, 1-dimethylethyl) -5' -octyl [1,1':3',1 "-terphenyl]-2'-olato-κO]](2-)]Dimethyl-having the formula C₈₆H₁₂₈F₂GeO₄Zr and the following structure ("catalyst 1"):

the catalyst used in the second reactor was zirconium, [ [2, 2' - [1, 3-propanediylbis (oxygen-. kappa.O) ]]Bis [3- [2, 7-bis (1, 1-dimethylethyl) -9H-carbazol-9-yl]]-5'- (dimethyloctylsilyl) -3' -methyl-5- (1,1,3, 3-tetramethylbutyl) [1,1 ]]-biphenyl]-2-olato-κO]](2-)]Dimethyl of formula C₁₀₇H₁₅₄N₂O₄Si₂Zr and the following structure ("catalyst 2"):

immediately following each reactor feed injection location, the feed stream is mixed with the circulating polymerization reactor contents using static mixing elements. The contents of each reactor are continuously circulated through a heat exchanger responsible for removing most of the heat of reaction, and wherein the temperature of the coolant side is responsible for maintaining the isothermal reaction environment at the specified reactor temperature. Circulation around each reactor loop is provided by a pump.

The effluent from the first polymerization reactor (containing solvent, monomer, hydrogen, catalyst components, and molten polymer) leaves the first reactor loop and passes through a control valve (responsible for controlling the pressure of the first reactor at a specified target) and is injected into a second polymerization reactor of similar design. The final effluent from the second polymerization reactor enters a zone where it is deactivated by the addition and reaction with a suitable reagent (water). At this same reactor outlet position, other additives were added for polymer stabilization. The final effluent stream is passed through another set of static mixing elements to promote catalyst deactivation and dispersion of additives.

After catalyst deactivation and addition of additives, the reactor effluent enters a devolatilization system where the polymer is removed from the non-polymer stream. The separated polymer melt was pelletized and collected. The non-polymer streams pass through various devices that separate most of the ethylene removed from the system. Most of the solvent is recycled back to the reactor after passing through the purification system. A small amount of solvent is purged from the process. The polyethylene composition 1 is stabilized with a small amount (ppm) of stabilizer.

The polymerization conditions of polyethylene composition 1 are shown in table 1. As shown in table 1, Cocat. 1 (bis (hydrogenated tallow alkyl) methyl, 1-amine tetrakis (pentafluorophenyl) borate and Cocat. 2 (modified methylaluminoxane (MMAO)) were used as cocatalysts for catalyst 1 and catalyst 2, respectively.

Polyethylene composition 2 was produced using the same catalyst system as polyethylene composition 1 and using the same process with comparable reaction conditions.

Other properties of polyethylene composition 1 and polyethylene composition 2 were measured using the test methods described above and are reported in table 2. The first polyethylene fraction refers to the polyethylene fraction from the first reactor and the second polyethylene fraction refers to the polyethylene fraction from the second reactor.

TABLE 1

TABLE 2

Limit of detection of this measurement < 3.

Target

The densities of the first polyethylene fraction of polyethylene composition 1, total polyethylene composition 1 and total polyethylene composition 2 were measured as described in the test methods section above. The density of the first polyethylene fraction of polyethylene composition 2 is the target value. The density of the second polyethylene fraction was calculated using the following blending rule:

polyethylene composition 1 and polyethylene composition 2 were evaluated relative to two comparative resins. Comparative composition A is ELITE^TM5960G, a high density reinforced polyethylene resin commercially available from the Dow chemical company, excluding Hyperform HPN-20E. Comparative composition A has 0.962g/cm³And a melt index (I) of 0.85g/10 min₂). Comparative composition B is a commercially available high density polyethylene resin having a density of 0.967g/cm³And melt index (I)₂) 1.2g/10 min and contained 1200ppm of Hyperform HPN-20E. Table 3 illustrates some of the differences in polymer design for these resins.

TABLE 3

Example 1

Polyethylene composition 1 and comparative compositions a and B were evaluated on a blown film line. The resin was dry blended with Hyperform HPN-20E nucleator (Milliken Chemical) provided in a masterbatch to target the final loadings of different HPN-20E nucleators ("HPN-20E") (targets: 0, 250, 750, 1250, 2500, and 5000ppm HPN-20E loadings) and further evaluated for water vapor barrier properties (MVTR or WVTR). The masterbatch containing HPN-20E comprises 3 wt.% HPN-20E, 1.5 wt.% silica, 0.5 wt.% hydrotalcite, 5 wt.% antioxidant and 90 wt.% carrier resin. The carrier resin has a density of 0.965g/cm³And melt index (I)₂) A high density polyethylene homopolymer with a narrow molecular weight distribution of 8.0g/10 min. Hyperform HPN-20E contains about 66 weight percent% calcium 1, 2-cyclohexanedicarboxylate and about 34% by weight zinc stearate/palmitate.

The blown film line used a twin screw extruder in which the specified resin and nucleating agent were dry blended and melted before being sent to a two inch diameter extrusion ring at a nominal rate of 15 lbs/hr. The extruder die temperature was set between 215 and 235 ℃. The blown film structure was a single layer film with a target thickness of 2 mils. The blow-up ratio target was 2.5, the frost line height ranged from-9 to 11 inches, and was flat at-7.9 inches. A film of bubbles of approximately 100 feet was produced and separated into two films.

The Water Vapor Transmission Rate (WVTR) of the film is measured, and it is particularly desirable that the WVTR be 0.10(g-mil)/(100 in)²Day). The results are shown in Table 4 with the units (g-mil)/(100 in)²Day).

TABLE 4

The composition as a blend of polyethylene composition 1 and HPN-20E, in particular 250-1250ppm, represents a polyethylene-based composition according to some embodiments of the invention. The composition blended with comparative composition a or comparative composition B is a comparative example. Note that the data for comparative composition B is not available at 0-750ppm, as it is commercially available with about 1200ppm HPN-20E. The polyethylene-based composition of the invention with 250ppm of HPN-20E provides the best WVTR performance.

Example 2

Collin 3 layer co-extrusion blown film line was used to make other film samples. Instead of the twin-screw extruder used in example 1, the blown film line had a single-screw extruder which fed an extrusion ring having a diameter of 2.36 inches. The nominal run rate was 30 lbs/hr and the extruder die temperature was set at-215 ℃. The blown film structure was a single layer film with a target thickness of 2 mils. The blow-up ratio target was 2.5, the frost line height was-5.5 inches, and the lay flat was-10 inches. A film of bubbles of approximately 100 feet was produced and separated into two films.

Three polyethylene-based compositions were prepared from polyethylene composition 1 by: (1) the polyethylene composition 1 was dry blended ("dry blended") with a HPN-20E masterbatch (as described in example 1) in a single screw extruder of a blown film line; (2) melt blending ("melt blending") polyethylene composition 1 and HPN-20E on a ZSK-26 extruder prior to providing the blended composition to a blown film line; and (3) melt blending polyethylene composition 1 and HPN-20E masterbatch on a ZSK-26 extruder (as described in example 1), followed by supplying the blend to a blown film line ("melt blending x 2"). The results are shown in Table 5.

TABLE 5

Each of the above compositions using 250-750ppm HPN-20E represents a polyethylene-based composition according to some embodiments of the invention. In particular, melt blending polyethylene composition 1 with 250HPN-20E provided particularly desirable WVTR values, nearly 20% lower than comparative composition B.

Example 3

In this example, many multilayer films were manufactured using a 7-layer Alpine blown film line. The multilayer film was made from five different layers, with a total nominal thickness of 2.2 mils and a blow-up ratio of 2.5. The membrane structure is: layer a (15%)/layer B (20%)/layer C (30%)/layer D (20%)/layer E (15%). The A layer is made of ELITE^TM5960G1 (Dow chemical Co.). Both layer B and layer D are INNATE^TMTH 60 (dow chemical company). The E layer is a sealing layer made of SEALUTION^TM220 (dow chemical company). Layer C is a barrier layer and is further described in table 6 below. The blend of polyethylene composition 1 and masterbatch HPN-20E (as described in example 1) was dry blended ("dry blended") in an extruder feeding the Alpine blown film line or melt blended with a ZSK40 twin screw extruder before being fed to the extruder of the Alpine blown film line ("melt blending"). Comparative composition B was evaluated as commercially available in layer C. The WVTR of the samples was measured and the results are shown in table 6.

TABLE 6

Polyethylene composition 1 and a blend of 250-750ppm HPN-20E represent polyethylene-based compositions according to some embodiments of the present invention. Providing a polyethylene-based composition having 750ppm HPN-20E produces particularly desirable WVTR results. In particular, melt blending polyethylene composition 1 with 750ppm HPN-20E provided about a 15% improvement in WVTR over comparative composition B.

Example 4

In this example, films formed from polyethylene composition 2 and comparative resin B were compared for dusting.

Polyethylene composition 2 was melt blended with Hyperform HPN-20E nucleating agent ("HPN-20E") provided in a masterbatch, as well as silica, hydrotalcite, antioxidant and HDPE carrier resin. The masterbatch comprises 3 wt% HPN-20E, 1.5 wt% silica, 0.5 wt% hydrotalcite, 5 wt% antioxidant and 90 wt% carrier resin. The carrier resin has a density of 0.965g/cm³And melt index (I)₂) A high density polyethylene homopolymer with a narrow molecular weight distribution of 8.0g/10 min. Hyperform HPN-20E contained about 66 wt% calcium 1, 2-cyclohexane dicarboxylate and about 34 wt% zinc stearate/palmitate. The polyethylene-based composition of the invention formed from polyethylene composition 2 and masterbatch ("polyethylene-based composition 2") comprised 750ppm of HPN-20E, 375ppm of silica, 125ppm of hydrotalcite, and 1,250ppm of antioxidant, based on the total weight of the polyethylene-based composition.

Comparative composition B contained about 1200ppm HPN-20E, believed to exclude any silica.

A monolayer film having a target thickness of 2 mils was produced on a blown film line from polyethylene-based composition 2 and comparative composition B. The blown film line was equipped with a screw single screw extruder, capable of producing polyethylene at speeds approaching 600 lbs/hr, using an 8 inch DSB II screw design. The target temperature profiles during extrusion were 177 ℃, 218 ℃, 193 ℃, 163 ℃, 221 ℃ and 227 ℃ through barrels 1-5, the screen blocks and the lower and upper dies, respectively. To produce a film, the composition was fed to an 8 inch blown film die having a 70 mil die gap and an output rate of 10.4 lbs/hr/inch of die circumference. The target melt temperature was 227 ℃ and the blow-up ratio was maintained at 2.5: 1. The air temperature in the air ring and air cooling unit was 7.2 ℃. Frost line height averages 34 inches. The film thickness was controlled to within + -10% (2 mils) by adjusting the nip speed. The width of the tiling of bubbles was 31 inches. The film is wound into a roll before slitting.

The films were evaluated for dusting. The dust on the film was collected on an 8.5 inch x11 inch black felt sheet that adhered to a fixed roller on the slitter/rewinder. The films slide on the stationary mat as they are wound through the machine. Dust was collected from 800 feet of each sample at a run rate of 200 feet/minute. The black felt sample was then carefully removed and visually inspected. The film sample formed from polyethylene-based composition 2 exhibited less dust than the film sample formed from comparative composition B.