Biaxially Oriented Film

Abstract

The biaxially oriented polyethylene film structure comprises at least three layers including a core layer, the core layer having a viscosity of i) 0.940 g / cm 3 and ii) 50 to 99.5 wt. % of a first polyethylene which is an ethylene copolymer having a density of at least 0.950 g / cm 3 and 0.5 to 50 weight percent of a second polyethylene, the polyethylene homopolymer composition having a density of from about 100 to about 500 nm, the polyethylene homopolymer composition further comprising a nucleating agent or mixture of nucleating agents. This biaxially oriented film has excellent optical properties.

Description

[Technical Field]

[0001] The present disclosure relates to a BOPE film or film structure that includes at least three layers and has good optical properties. [Background technology]

[0002] Biaxially oriented polyethylene (BOPE) films are typically prepared by stretching a thick precursor (or base) film, known as a cast sheet, in two directions: the machine direction (MD) and the transverse direction (TD). Stretching can be done in a single step (simultaneous biaxial stretching) or in two successive steps (sequential biaxial stretching). The equipment commonly used in the stretching process is commonly called a "tenter frame" line.

[0003] Compared to conventional blown films, BOPE films can achieve up to twice the stiffness (tensile modulus), and offer improved tensile strength, impact strength, puncture resistance, flex crack resistance, and improved (i.e., lower) optical haze.

[0004] BOPE films may be suitable for a wide variety of packaging applications, and the improved properties observed in biaxially oriented films or film structures may enable the design of "all-polyethylene" packages (as opposed to packages made with a different type of polymer), which would be inherently more recyclable.

[0005] The tenter frame process is widely used to prepare biaxially oriented polypropylene (BOPP) and biaxially oriented polyethylene terephthalate (BOPET) films. However, polyethylene is relatively difficult to stretch / biaxially orient, which has limited the commercial use of BOPE. Prior to this work, the tenter frame process was not widely used, particularly for high density polyethylene (e.g., about 0.950 g / cm).3 It has been observed that high-density polyethylene (high density polyethylene having a density above 1000 kJ / cm) behaves poorly when subjected to biaxial orientation. Indeed, specific or precise process conditions (i.e., a very narrow process window) have been required to produce BOPE films from high-density polyethylene. Alternatively, high-density polyethylene has been coextruded using adhesion promoter layers ("casting promoters"), such as layers comprising low-density polyethylene materials and blends thereof, or layers comprising ethylene / propylene copolymers and terpolymers, as adjacent coextruded layers. Alternatively, high-density polyethylene has been coextruded using adhesion promoter layers ("casting promoters"), such as layers comprising low-density polyethylene materials and blends thereof, or ethylene / propylene copolymers and terpolymers, as adjacent coextruded layers.

[0006] There remains a need for new polyethylene compositions, particularly high density polyethylene compositions that provide improved "stretchability" in BOPE processes, such as tenter frame BOPE processes. Summary of the Invention

[0007] In one embodiment of the present disclosure, provided is an "all-polyethylene" biaxially oriented film structure that has good optical properties and may have improved recyclability compared to BOPE films made from mixed polymer materials.

[0008] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise at least 50 wt. % of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; It is a biaxially oriented polyethylene film structure.

[0009] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first skin layer adjacent to a first side of the core layer; a second skin layer adjacent to the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; The first skin layer and the second skin layer each comprise at least 50% by weight of a third polyethylene, the third polyethylene being a biaxially oriented polyethylene film structure having a density lower than that of the first polyethylene.

[0010] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a high density polyethylene having a density of the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise at least 50 wt. % of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; The biaxially oriented polyethylene film structure is a biaxially oriented polyethylene film structure having a haze value of less than 15%.

[0011] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first skin layer adjacent to a first side of the core layer; a second skin layer adjacent to the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a high density polyethylene having a density of the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; the first skin layer and the second skin layer each comprise at least 50 wt. % of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; The biaxially oriented polyethylene film structure is a biaxially oriented polyethylene film structure having a haze value of less than 15%.

[0012] In one embodiment of the present disclosure, the third polyethylene is selected from the group consisting of linear low density polyethylene (LLDPE) and medium density polyethylene (MDPE). [Brief explanation of the drawings]

[0013] [Figure 1] 1 shows a schematic diagram of a multi-zone reactor system including a first polymerization zone defined by a first tubular reactor, a second polymerization zone defined by a tank reactor, and a third polymerization zone defined by a second tubular reactor. The schematic diagram is merely representative of the multi-zone reactor system and is not drawn to scale. The approximate locations of hydrogen addition to the multi-zone reactor system are also shown (locations A and B). DETAILED DESCRIPTION OF THE INVENTION

[0014] As used herein, the term "monomer" refers to a small molecule that can chemically react and chemically bond with itself or other monomers to form a polymer.

[0015] As used herein, the term "α-olefin" or "alpha-olefin" is used to describe a monomer having a linear hydrocarbon chain containing 3 to 20 carbon atoms with a double bond at one end of the chain; an equivalent term is "linear α-olefin." Alpha-olefins are also referred to as comonomers.

[0016] As used herein, the terms "polyethylene," "polyethylene composition," or "ethylene polymer" refer to a polymer produced from ethylene monomer and, optionally, one or more additional monomers, regardless of the specific catalyst or process used to make the ethylene polymer. In the polyethylene field, the one or more additional monomers are often referred to as "comonomers" and typically comprise an α-olefin. The term "homopolymer" generally refers to a polymer containing only one type of monomer. The term "copolymer" refers to a polymer containing two or more types of monomers. Common types of polyethylene include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), or very low-density polyethylene (ULDPE), also known as plastomers and elastomers. The term polyethylene also includes polyethylene terpolymers, which may contain two or more comonomers in addition to ethylene. The term polyethylene also includes combinations or blends of the above types of polyethylene.

[0017] The term "heterogeneously branched polyethylene" refers to a subset of polymers in the ethylene polymer group that are produced using heterogeneous catalyst systems, non-limiting examples of which include Ziegler-Natta catalysts or chromium catalysts, both of which are well known in the art.

[0018] The term "homogeneously branched polyethylene" refers to a subset of polymers of the ethylene polymer group produced using single-site catalysts, non-limiting examples of which include metallocene catalysts, phosphinimine catalysts, and constrained geometry catalysts, all of which are well known in the art.

[0019] Typically, homogeneously branched polyethylene has a narrow molecular weight distribution, e.g., M w / M nValues ​​are less than about 2.8, especially less than about 2.3, although exceptions may occur, and M w and M n refers to the weight and number average molecular weights, respectively. In contrast, M for heterogeneously branched ethylene polymers w / M n is typically the M of homogeneous polyethylene w / M n Generally, homogeneously branched ethylene polymers also have a narrow comonomer distribution, i.e., each polymer within the molecular weight distribution has a similar comonomer content. The Composition Distribution Breadth Index (CDBI) is often used to quantify how the comonomer is distributed within an ethylene polymer and to distinguish between ethylene polymers produced with different catalysts or processes. 50 is defined as the percentage of ethylene polymers whose composition is within 50 weight percent (wt%) of the median comonomer composition, which is consistent with the definition set forth in WO 93 / 03093, assigned to Exxon Chemical Patents Inc. CDBI for ethylene copolymers 50 can be calculated from the TREF (Temperature Rising Elution Fractionation) curve, and the TREF method is described in Wild et al., J. Polym. Sci., Part B, Polym. Phys., Vol. 20(3), pp. 441-455. Typically, the CDBI of a homogeneously branched ethylene polymer is 50 is greater than about 70% or greater than about 75%. In contrast, the CDBI of heterogeneously branched α-olefin-containing ethylene polymers is 50 is generally a CDBI of homogeneous ethylene polymers. 50 For example, the CDBI of heterogeneously branched ethylene polymers is 50 may be less than about 75%, or less than about 70%.

[0020] As is well known to those skilled in the art, homogeneously branched ethylene polymers are often further subdivided into "linear homogeneous ethylene polymers" and "substantially linear homogeneous ethylene polymers." These two subgroups differ in the amount of long chain branching. More specifically, linear homogeneous ethylene polymers have less than about 0.01 long chain branches per 1000 carbon atoms, while substantially linear ethylene polymers have from about 0.01 to greater than about 3.0 long chain branches per 1000 carbon atoms. The long chain branches are polymeric in nature, i.e., similar in length to the polymers to which they are attached. Hereinafter, in this disclosure, the terms "homogeneously branched polyethylene" or "homogeneously branched ethylene polymer" refer to both linear homogeneous ethylene polymers and substantially linear homogeneous ethylene polymers.

[0021] In this disclosure, the terms "ethylene homopolymer" or "polyethylene homopolymer" are used to refer to a polymer that is the product of a polymerization process in which only ethylene is intentionally added or intentionally present as the polymerizable monomer.

[0022] In this disclosure, the terms "ethylene copolymer" or "polyethylene copolymer" mean that the polymer is the product of a polymerization process in which ethylene and one or more α-olefins are intentionally added or intentionally present as polymerizable monomers.

[0023] As used herein, the term "unsubstituted" means that a hydrogen radical is attached to the molecular group that follows the term "unsubstituted." The term "substituted" means that the group that follows the term has one or more moieties (non-hydrogen radicals) replacing one or more hydrogen radicals anywhere within the group.

[0024] The term "film" is used herein to mean a film having one or more layers formed by extruding a polymer through one or more die openings. The term "film structure" is used to mean that the film has a plurality of layers (a film structure that can have at least two layers, at least three layers, at least four layers, at least five layers, etc.).

[0025] In the present disclosure, the terms "biaxially oriented polyethylene film", "BOPE film", "biaxially oriented polyethylene film structure", or "BOPE film structure" generally refer to a biaxially oriented film or film structure in which polyethylene is the main component polymer (i.e., polyethylene is present at a higher weight % than other non-polyethylene polymers based on the total weight of the polymers present in the film or film structure).

[0026] The phrase "all polyethylene" as used herein, when used to describe a film or film structure, means that the film or film structure is composed of at least 90% by weight of polyethylene (in contrast to non-polyethylene-based polymer materials or compositions) based on the total weight of the polymers present in the film or film structure.

[0027] The "skin" layer is the outer layer of a multilayer film structure (i.e., the layer having an outer surface exposed to the environment).

[0028] The "core" layer is the inner layer of a multilayer film structure (i.e., the layer adjacent to the inner surface of the skin layer, or the layer adjacent to another inner layer, or the layer adjacent to another core layer). A multilayer film structure can have one or more core layers that are considered adjacent inner layers.

[0029] <BOPE film structure> In one embodiment of the present invention, the biaxially oriented polyethylene film structure has at least three layers including at least one core layer, At least one core layer comprises: i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a high density polyethylene having a density of The high density polyethylene includes a nucleating agent or mixture of nucleating agents.

[0030] In one embodiment of the present invention, the biaxially oriented polyethylene film structure has at least three layers, including at least one core layer: At least one core layer comprises: i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of The polyethylene homopolymer composition includes a nucleating agent or mixture of nucleating agents.

[0031] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a high density polyethylene having a density of the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; The first adjacent layer and the second adjacent layer each comprise a third polyethylene, the third polyethylene being a biaxially oriented polyethylene film structure having a density lower than that of the first polyethylene.

[0032] In an embodiment of the present disclosure, the biaxially oriented polyethylene film structure comprises: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a high density polyethylene having a density of the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; The first adjacent layer and the second adjacent layer each comprise at least 50% by weight (based on the weight of the polymeric material used to make each of the first adjacent layer and the second adjacent layer) of a third polyethylene, the third polyethylene being a biaxially oriented polyethylene film structure having a density lower than that of the first polyethylene.

[0033] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first skin layer adjacent to a first side of the core layer; a second skin layer adjacent to the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a high density polyethylene having a density of the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; The first skin layer and the second skin layer each comprise a third polyethylene, the third polyethylene being a biaxially oriented polyethylene film structure having a density lower than that of the first polyethylene.

[0034] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first skin layer adjacent to a first side of the core layer; a second skin layer adjacent to the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a high density polyethylene having a density of the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; The first skin layer and the second skin layer each comprise at least 50% by weight of a third polyethylene, the third polyethylene being a biaxially oriented polyethylene film structure having a density lower than that of the first polyethylene.

[0035] In one embodiment of the present disclosure, the core layer is i) 70-99.5 wt% of a first polyethylene, the first polyethylene having a viscosity of 0.940 g / cm 3 and ii) 0.5 to 30 wt. % of a second polyethylene, the second polyethylene being an ethylene copolymer having a density of at least 0.950 g / cm. 3 and a second polyethylene which is a high density polyethylene having a density of 0.05 to 0.5, wherein the high density polyethylene includes a nucleating agent or a mixture of nucleating agents. In one embodiment of the present disclosure, the core layer is i) 90-99.5 wt% of a first polyethylene, the first polyethylene having a density of 0.940 g / cm 3 and ii) 0.5 to 10 wt. % of a second polyethylene, the second polyethylene being an ethylene copolymer having a density greater than 0.950 g / cm. 3 and a second polyethylene which is a high density polyethylene having a density of 0.05 to 0.5, wherein the high density polyethylene includes a nucleating agent or a mixture of nucleating agents.

[0036] In one embodiment of the present disclosure, the nucleating agent or mixture of nucleating agents present in the high density polyethylene is present in an amount to provide 1 to 1000 ppm (parts per million) of the nucleating agent or mixture of nucleating agents based on the total weight of the polymeric materials used in the core layer (i.e., based on the total weight of i) the first polyethylene and ii) the high density polyethylene used in the core layer). In further embodiments of the present disclosure, the nucleating agent or mixture of nucleating agents present in the high density polyethylene is present in an amount to provide from 5 to 1,000 ppm (parts per million), or from 5 to 750 ppm, or from 5 to 500 ppm, or from 5 to 400 ppm, or from 5 to 350 ppm, or from 5 to 250 ppm, or from 5 to 150 ppm, or from 5 to 100 ppm of nucleating agent or mixture of nucleating agents, based on the total weight of the polymeric material used in the core layer (i.e., based on the total weight of i) the first polyethylene and ii) the high density polyethylene used in the core layer). In further embodiments of the present disclosure, the nucleating agent or mixture of nucleating agents present in the high density polyethylene is present in an amount to provide less than 500 ppm (parts per million), or less than 350 ppm, or less than 250 ppm, or less than 150 ppm, or less than 100 ppm, or less than 75 ppm, or less than 50 ppm, or less than 40 ppm, or less than 30 ppm, or less than 25 ppm, or less than 20 ppm, or less than 15 ppm, or less than 10 ppm of nucleating agent or mixture of nucleating agents, based on the total weight of the polymeric material used in the core layer (i.e., based on the total weight of i) the first polyethylene and ii) the high density polyethylene used in the core layer).

[0037] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; It is a biaxially oriented polyethylene film structure.

[0038] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise at least 50 wt. % (based on the weight of the polymeric material used to make each of the first adjacent layer and the second adjacent layer) of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; It is a biaxially oriented polyethylene film structure.

[0039] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first skin layer adjacent to a first side of the core layer; a second skin layer adjacent to the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; the first skin layer and the second skin layer each comprise a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; It is a biaxially oriented polyethylene film structure.

[0040] One embodiment of the present disclosure is a biaxially oriented polyethylene film structure comprising: A core layer; a first skin layer adjacent to a first side of the core layer; a second skin layer adjacent to the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; the first skin layer and the second skin layer each comprise at least 50 wt. % (based on the weight of the polymeric material used to make each of the first skin layer and the second skin layer) of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; It is a biaxially oriented polyethylene film structure.

[0041] In one embodiment of the present disclosure, the core layer is i) 70-99.5 wt% of a first polyethylene, the first polyethylene having a viscosity of 0.940 g / cm 3 and ii) 0.5 to 30 wt. % of a second polyethylene, the second polyethylene being an ethylene copolymer having a density of at least 0.950 g / cm. 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of from about 100 to about 1500 nm, wherein the polyethylene homopolymer composition includes a nucleating agent or mixture of nucleating agents. In one embodiment of the present disclosure, the core layer is i) 90-99.5 wt% of a first polyethylene, the first polyethylene having a density of 0.940 g / cm 3 and ii) 0.5 to 10 wt. % of a second polyethylene, the second polyethylene being an ethylene copolymer having a density greater than 0.950 g / cm. 3 and a second polyethylene which is a polyethylene homopolymer composition having a density of from about 100 to about 1500 nm, wherein the polyethylene homopolymer composition includes a nucleating agent or mixture of nucleating agents.

[0042] In one embodiment of the present disclosure, the nucleating agent or mixture of nucleating agents present in the polyethylene homopolymer composition is present in an amount to provide 1 to 1000 ppm (parts per million) of the nucleating agent or mixture of nucleating agents, based on the total weight of the polymeric materials used in the core layer (i.e., based on the total weight of i) the first polyethylene and ii) the polyethylene homopolymer composition used in the core layer). In further embodiments of the present disclosure, the nucleating agent or mixture of nucleating agents present in the polyethylene homopolymer composition is present in an amount to provide from 5 to 1000 ppm (parts per million), or from 5 to 750 ppm, or from 5 to 500 ppm, or from 5 to 400 ppm, or from 5 to 350 ppm, or from 5 to 250 ppm, or from 5 to 150 ppm, or from 5 to 100 ppm of nucleating agent or mixture of nucleating agents, based on the total weight of polymeric material used in the core layer (i.e., based on the total weight of i) the first polyethylene and ii) the polyethylene homopolymer composition used in the core layer). In further embodiments of the present disclosure, the nucleating agent or mixture of nucleating agents present in the polyethylene homopolymer composition is present in an amount to provide less than 500 ppm (parts per million), or less than 350 ppm, or less than 250 ppm, or less than 150 ppm, or less than 100 ppm, or less than 75 ppm, or less than 50 ppm, or less than 40 ppm, or less than 30 ppm, or less than 25 ppm, or less than 20 ppm, or less than 15 ppm, or less than 10 ppm of nucleating agent or mixture of nucleating agents, based on the total weight of polymeric material used in the core layer (i.e. based on the total weight of i) the first polyethylene and ii) the polyethylene homopolymer composition used in the core layer).

[0043] In one embodiment of the present disclosure, the first adjacent layer and the second adjacent layer each comprise at least 70% by weight (based on the weight of the polymeric material used to make each of the first adjacent layer and the second adjacent layer) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene. In one embodiment of the present disclosure, the first adjacent layer and the second adjacent layer each comprise at least 90% by weight (based on the weight of the polymeric material used to make each of the first adjacent layer and the second adjacent layer) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene. In an embodiment of the present disclosure, the first adjacent layer and the second adjacent layer each comprise at least 95% or at least 99% by weight (based on the weight of the polymeric material used to make the first adjacent layer and the second adjacent layer, respectively) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene. In one embodiment of the present disclosure, the first adjacent layer and the second adjacent layer each comprise 100% by weight (based on the weight of the polymeric material used to make each of the first adjacent layer and the second adjacent layer) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene.

[0044] In embodiments of the present disclosure, in addition to the third polyethylene, the first adjacent layer and the second adjacent layer may each comprise (based on the weight of the polymeric material used to make each of the first adjacent layer and the second adjacent layer) 50% by weight or less, or 30% by weight or less, or 10% by weight or less, or 5% by weight or less, or 1% by weight or less of the following polyethylenes: a) 0.940 g / cm 3 a first polyethylene which is a copolymer having a density greater than b) at least 0.950 g / cm 3 a second polyethylene which is a high density polyethylene having a density of c) Another polyethylene different from the first, second, and third polyethylenes, which may be selected from the group consisting of linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), very low density polyethylene (VLDPE), and high pressure low density polyethylene (HPLDPE) prepared by free radical polymerization of ethylene.

[0045] In one embodiment of the present disclosure, the first skin layer and the second skin layer each comprise at least 70% by weight (based on the weight of the polymeric material used to make each of the first skin layer and the second skin layer) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene. In one embodiment of the present disclosure, the first skin layer and the second skin layer each comprise at least 90% by weight (based on the weight of the polymeric material used to make each of the first skin layer and the second skin layer) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene. In one embodiment of the present disclosure, the first skin layer and the second skin layer each comprise at least 95% or at least 99% by weight (based on the weight of the polymeric material used to make the first skin layer and the second skin layer, respectively) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene. In one embodiment of the present disclosure, the first skin layer and the second skin layer each comprise 100% by weight (based on the weight of the polymeric material used to make each of the first skin layer and the second skin layer) of a third polyethylene, wherein the third polyethylene has a density lower than the density of the first polyethylene.

[0046] In embodiments of the present disclosure, in addition to the third polyethylene, the first skin layer and the second skin layer may each comprise (based on the weight of the polymeric material used to make each of the first skin layer and the second skin layer) up to 50%, or up to 30%, or up to 10%, or up to 5%, or up to 1% by weight of the following polyethylene: a) 0.940 g / cm 3 a first polyethylene which is a copolymer having a density greater than b) at least 0.950 g / cm 3 a second polyethylene which is a high density polyethylene having a density of c) Another polyethylene different from the first, second, and third polyethylenes, which may be selected from the group consisting of linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), very low density polyethylene (VLDPE), and high pressure low density polyethylene (HPLDPE) prepared by free radical polymerization of ethylene.

[0047] In one embodiment, the biaxially oriented film or film structure includes a core layer, a first adjacent layer adjacent to a first side of the core layer, and a second adjacent layer adjacent to a second side of the core layer, wherein the core layer comprises at least 50% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure includes a core layer, a first adjacent layer adjacent to a first side of the core layer, and a second adjacent layer adjacent to a second side of the core layer, wherein the core layer comprises at least 60% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure includes a core layer, a first adjacent layer adjacent to a first side of the core layer, and a second adjacent layer adjacent to a second side of the core layer, wherein the core layer comprises at least 70% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure includes a core layer, a first adjacent layer adjacent to a first side of the core layer, and a second adjacent layer adjacent to a second side of the core layer, wherein the core layer comprises at least 80% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure includes a core layer, a first adjacent layer adjacent to a first side of the core layer, and a second adjacent layer adjacent to a second side of the core layer, wherein the core layer comprises at least 90% by weight of the total weight of the biaxially oriented film or film structure.

[0048] In one embodiment, the biaxially oriented film or film structure includes a core layer, a first skin layer adjacent to a first side of the core layer, and a second skin layer adjacent to a second side of the core layer, wherein the core layer comprises at least 50% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure includes a core layer, a first skin layer adjacent to a first side of the core layer, and a second skin layer adjacent to a second side of the core layer, wherein the core layer comprises at least 60% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure includes a core layer, a first skin layer adjacent to a first side of the core layer, and a second skin layer adjacent to a second side of the core layer, wherein the core layer comprises at least 70% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure comprises a core layer, a first skin layer adjacent to a first side of the core layer, and a second skin layer adjacent to a second side of the core layer, wherein the core layer comprises at least 80% by weight of the total weight of the biaxially oriented film or film structure. In one embodiment, the biaxially oriented film or film structure comprises a core layer, a first skin layer adjacent to a first side of the core layer, and a second skin layer adjacent to a second side of the core layer, wherein the core layer comprises at least 90% by weight of the total weight of the biaxially oriented film or film structure.

[0049] Biaxially oriented polyethylene (BOPE) films or film structures can be made using a tenter frame process in one embodiment of the present disclosure.

[0050] The tenterframe process is commonly used to prepare biaxially oriented films and is suitable for use in embodiments of the present disclosure. The tenterframe process is well known to those skilled in the art of film manufacturing. The process begins with an extruder equipped with a slot die to form a sheet or film. For convenience, this extruded sheet or film may be referred to as the "base film" or "base film structure" or "base structure." Once the base structure is quenched on a chill roll and reheated, machine direction (MD) stretching or machine direction orientation (MDO) is achieved by pulling the base structure using several closely spaced rolls rotating at gradually increasing surface speeds. Following MD stretching, clips (attached to chains) grab the edges of the moving sheet (or film, or web) and transport it to an oven. Within the oven, the edges of the base structure are pulled apart, widening the sheet and providing transverse direction orientation (TDO). This orientation / stretching thins the film structure in proportion to the orientation ratio or stretch ratio. For example, to prepare a 1 mil finished BOPE film with a 5:1 stretch ratio in the machine direction (MD) and an 8:1 stretch ratio in the transverse direction (TD), the process may begin with a 40 mil thick film or sheet.

[0051] In embodiments of the present disclosure, the machine direction (MD) stretch ratio may range from about 5:1 to about 9:1, and the transverse direction (TD) stretch ratio may range from about 7:1 to about 12:1. In other embodiments of the present disclosure, the machine direction (MD) stretch ratio may range from about 3:1 to about 12:1, and the transverse direction (TD) stretch ratio may range from about 3:1 to about 12:1. In yet other embodiments of the present disclosure, the machine direction (MD) stretch ratio may range from about 5:1 to about 12:1, and the transverse direction (TD) stretch ratio may range from about 5:1 to about 12:1. In yet other embodiments of the present disclosure, the machine direction (MD) stretch ratio may range from about 3:1 to about 10:1, and the transverse direction (TD) stretch ratio may range from about 3:1 to about 10:1.

[0052] Details of the biaxial orientation process are provided in the textbook "Film Processing Advances" by Kanai T. et al. (2014); Hanser Publishers. However, in general, the sequential biaxial orientation process includes the following: cast extrusion of a relatively thick base film structure through a slot die, followed by cooling on a chill roll (or using a water bath); stretching the base film structure in the machine direction using heated rollers that rotate at gradually increasing speeds; stretching the film structure in the transverse direction by pulling each end of the film structure with clips attached to the ends of the film structure, where the clips move apart as they pull the film forward, pulling the gripped film ends in the transverse direction (i.e., stretching occurs in the transverse direction); passing the film structure through an oven to anneal it; optionally surface treating the film structure; trimming the unstretched ends of the film structure held by the clips; and finally winding the film structure.

[0053] Although sequential biaxial stretching is used in embodiments of the present disclosure, sequential biaxial orientation can, in some embodiments, cause film quality problems. For example, in some embodiments, the optics of the film or multilayer film structure can be compromised. Therefore, in certain embodiments, an alternative unit operation involving simultaneous machine direction / transverse direction stretching in a single process step may be preferred. In one embodiment, during simultaneous stretching, the base film may be held by tenter clips (as described above) and suspended in air while stretching in both the MD and TD directions.

[0054] In embodiments of the present disclosure, biaxially oriented films or film structures comprising at least three layers have a haze value of 20% or less, or less than 20%, or 15% or less, or less than 15%, or 10% or less, or less than 10%, or 7.5% or less, or less than 7.5%. In embodiments of the present disclosure, biaxially oriented films or film structures comprising at least three layers have a transparency value of 80% or greater, or greater than 80%, or 85% or greater, or greater than 85%, or 90% or greater, or greater than 90%, or 95% or greater, or greater than 95%.

[0055] In an embodiment of the present disclosure, a biaxially oriented film or film structure comprising a core layer, a first adjacent layer adjacent to a first side of the core layer, and a second adjacent layer adjacent to a second side of the core layer has a haze value of 20% or less, or less than 20%, or 15% or less, or less than 15%, or 10% or less, or less than 10%, or 7.5% or less, or less than 7.5. In an embodiment of the present disclosure, a biaxially oriented film or film structure comprising a core layer, a first adjacent layer adjacent to a first side of the core layer, and a second adjacent layer adjacent to a second side of the core layer has a transparency value of 80% or greater, or greater than 80%, or 85% or greater, or greater than 85%, or 90% or greater, or greater than 90%, or 95% or greater, or greater than 95%.

[0056] In an embodiment of the present disclosure, a biaxially oriented film or film structure comprising a core layer, a first skin layer adjacent a first side of the core layer, and a second skin layer adjacent a second side of the core layer has a haze value of 20% or less, or less than 20%, or 15% or less, or less than 15%, or 10% or less, or less than 10%, or 7.5% or less, or less than 7.5. In an embodiment of the present disclosure, a biaxially oriented film or film structure comprising a core layer, a first skin layer adjacent to a first side of the core layer, and a second skin layer adjacent to a second side of the core layer has a transparency value of 80% or greater, or greater than 80%, or 85% or greater, or greater than 85%, or 90% or greater, or greater than 90%, or 95% or greater, or greater than 95%.

[0057] Biaxially oriented films prepared according to the present disclosure may be suitable for use in a wide variety of packaging applications. In one embodiment, the biaxially oriented film structure can be used in a laminate structure. For example, the biaxially oriented film structure of the present disclosure can be used as a printing web when laminated to a sealant web, also made from polyethylene, which may include a lower density polyethylene material. This type of laminate structure can be more easily recycled compared to conventional laminate structures that include a layer of polyester or polypropylene laminated to a layer of polyethylene.

[0058] Further embodiments of the first polyethylene used in the biaxially oriented film structure are given below.

[0059] Further embodiments of the second polyethylene for use in biaxially oriented film structures are given below.

[0060] A further embodiment of a third polyethylene for use in biaxially oriented film structures is given below.

[0061] <First Polyethylene> In one embodiment of the present disclosure, the first polyethylene is made using a multi-site catalyst system, non-limiting examples of which include Ziegler-Natta polymerization catalysts and chromium catalysts, both of which are well known in the art.

[0062] In one embodiment of the present disclosure, the first polyethylene is made using a Ziegler-Natta polymerization catalyst known in the art.

[0063] In one embodiment of the present disclosure, the first polyethylene is made using a Ziegler-Natta polymerization catalyst in a solution phase polymerization process. In one embodiment of the present disclosure, the first polyethylene is made using a Ziegler-Natta polymerization catalyst in a solution phase polymerization process conducted in a multi-zone polymerization reactor system. In one embodiment of the present disclosure, the first polyethylene is made using a Ziegler-Natta polymerization catalyst in a solution phase polymerization process conducted in a multi-zone polymerization reactor system, the multi-zone reactor system comprising first, second and third polymerization zones.

[0064] In one embodiment of the present disclosure, the first polyethylene is an ethylene copolymer.

[0065] In embodiments of the present disclosure, the alpha-olefin that may be copolymerized with ethylene to make the first polyethylene may be selected from the group including 1-butene, 1-pentene, 1-hexene, and 1-octene, and mixtures thereof.

[0066] In one embodiment of the present disclosure, the first polyethylene comprises ethylene and at least one alpha olefin having from 4 to 8 carbon atoms.

[0067] In one embodiment of the present disclosure, the first polyethylene is an ethylene / 1-butene copolymer.

[0068] In an embodiment of the present disclosure, the first polyethylene has a viscosity of at least 0.940 g / cm 3 , or 0.940 g / cm 3 More than or at least 0.941 g / cm 3 It has a density of

[0069] In an embodiment of the present disclosure, the first polyethylene has a density of 0.940 to 0.965 g / cm 3 , or 0.940 to 0.963 g / cm 3 , or 0.941 to 0.965 g / cm 3 , or 0.941 to 0.963 g / cm 3, or 0.941 to 0.962 g / 10 min, or 0.940 to 0.960 g / cm 3 , or 0.940 to 0.958 g / cm 3 , or 0.940 to 0.956 g / cm 3 , or 0.940 to 0.952 g / cm 3 , or 0.940 to 0.950 g / cm 3 , or 0.942 to 0.960 g / cm 3 , or 0.942 to 0.958 g / cm 3 , or 0.942 to 0.956 g / cm 3 , or 0.942 to 0.952 g / cm 3 , or 0.942 to 0.950 g / cm 3 It has a density of

[0070] In embodiments of the present disclosure, the first polyethylene has a melt index I2 of at least 0.50 g / 10 min, or at least 0.75 g / 10 min, or at least 0.80 g / 10 min, or at least 1.0 g / 10 min. In an embodiment of the present disclosure, the melt index I2 of the first polyethylene may be from about 0.01 g / 10 min to about 10.0 g / 10 min, or from about 0.1 g / 10 min to about 10.0 g / 10 min, or from about 0.5 to about 10.0 g / 10 min, or from about 0.1 g / 10 min to about 5.0 g / 10 min, or from about 0.1 g / 10 min to about 3.0 g / 10 min, or from about 0.5 g / 10 min to about 5.0 g / 10 min, or from about 0.5 g / 10 min to about 3.0 g / min, or from about 0.5 g / 10 min to about 2.5 g / 10 min.

[0071] In an embodiment of the present disclosure, the melt flow ratio (MFR) I of the first polyethylene 21 / I2 is greater than 50, or greater than 60, or greater than 65, or greater than 70, or greater than 75. In one embodiment of the present disclosure, the melt flow ratio (MFR) I of the first polyethylene 21 / I2 is less than 115. In an embodiment of the present disclosure, the melt flow ratio (MFR) I of the first polyethylene 21 / I2 is 50 to 120, or 50 to 115, or more than 65 and less than 115, or more than 75 and less than 115.

[0072] In one embodiment of the present disclosure, the first polyethylene has a molecular weight of about 5,000 to about 75,000, or about 5,000 to about 50,000, or about 5,000 to about 30,000, or about 5,000 to about 25,000, or about 7,500 to about 50,000, or about 7,500 to about 30,000, or about 7,500 to about 25,000, or about 5,000 to about 20,000, or about 5, A number average molecular weight M of 1,000 to about 15,000, or about 7,500 to about 20,000, or about 7,500 to about 15,000, or about 10,000 to about 15,000, or about 10,000 to about 12,500, or about 11,000 to about 15,000, or about 11,000 to about 12,500, or more than 11,000 but less than 12,500, or more than 11,000 but less than 15,000. n It has.

[0073] In one embodiment of the present disclosure, the first polyethylene has a weight average molecular weight M of about 75,000 to about 250,000, or about 80,000 to about 200,000, or about 90,000 to about 175,000, or about 100,000 to about 175,000, or about 90,000 to about 150,000, or about 100,000 to about 150,000, or about 100,000 to about 125,000, or about 90,000 to about 130,000, or about 90,000 to about 125,000, or about 85,000 to about 140,000, or about 85,000 to about 150,000, or more than about 85,000 but less than about 140,000. w It has.

[0074] In one embodiment of the present disclosure, the first polyethylene has a Z-average molecular weight M of at least 500,000, or greater than 500,000, or at least 550,000, or greater than 550,000, or at least 600,000, or greater than 600,000. z It has. In one embodiment of the present disclosure, the first polyethylene has a Z-average molecular weight M of about 500,000 to about 800,000, or greater than 500,000 to about 800,000, or greater than 500,000 to less than 800,000, or about 500,000 to 750,000, or about 525,000 to about 750,000, or about 550,000 to about 750,000, or about 575,000 to about 750,000, or about 550,000 to about 725,000, or about 575,000 to about 725,000, or about 600,000 to about 700,000. z It has.

[0075] In an embodiment of the present disclosure, the first polyethylene has a molecular weight distribution M of 3.0 to 20.0, or greater than 3.0 to 18.0, or 3.5 to 16.0. w / M n It has. In an embodiment of the present disclosure, the first polyethylene has a molecular weight distribution M of 8.0 to 12.0, or greater than 8.0 to 12.0, or greater than 8.5 to 12.0, or 9.0 to 12.0, or greater than 9.0 to less than 12.0, or 9.0 to 11.5, or 8.5 to 11.5, or 9.0 to 11.0, or 8.0 to 11.0, or 9.0 to 10.5, or 9.5 to 10.5. w / M n It has.

[0076] In an embodiment of the present disclosure, the first polyethylene has a molecular weight distribution M of 3.5 to 8.0, or 4.0 to 8.0, or 4.0 to 7.5, or 4.0 to 7.0, or 4.5 to 7.5, or 4.5 to 7.0, or 4.5 to 6.5, or 5.0 to 7.0, or 5.5 to 7.0, or 5.0 to 6.5, or 5.5 to 6.5, or more than 5.0 to less than 6.5, or 5.0 to 6.25, or 5.0 to 6.0. w / M n It has.

[0077] In one embodiment of the present disclosure, the first polyethylene has a Log 10 [I6 / I2] / Log 10It has a stress index defined as [6.48 / 2.16], and this stress index is 1.60 to 2.00, or 1.65 to 2.00, or 1.70 to 2.00, or 1.75 to 1.95, or 1.75 to 1.90, or 1.80 to 1.95, or 1.80 to 1.90, or more than 1.80 but less than 1.90.

[0078] In one embodiment of the present disclosure, the first polyethylene is characterized by having a high Mz of about 500,000 or more and a broad molecular weight distribution (Mw / Mn) of about 9.0 to about 12.0.

[0079] In an embodiment of the present disclosure, the first polyethylene has a composition distribution breadth index (CDBI) of 40 to 75 wt%, or 50 to 70 wt%, or 55 to 70 wt%, or 55 to 65 wt%. 50 It has.

[0080] In an embodiment of the present disclosure, the first polyethylene has a composition distribution breadth index (CDBI) of 35 to 65 wt%, or 35 to 60 wt%, or 35 to 55 wt%, or 40 to 60 wt%, or 40 to 55 wt%, or 40 to 50 wt%, or more than 40 wt% and less than 50 wt%. 25 It has.

[0081] In one embodiment of the present disclosure, the first polyethylene has a unimodal profile in gel permeation chromatography (GPC). The term "unimodal" is defined herein to mean the presence of only one clear, significant peak or maximum in a GPC curve. A unimodal profile includes broad unimodal profiles. A unimodal profile may also include shoulders or buried peaks that cannot be easily separated or deconvoluted into clearly defined, unique peaks.

[0082] In one embodiment of the present disclosure, the first polyethylene has a normal comonomer distribution profile as measured using GPC-FTIR. If the comonomer incorporation decreases with molecular weight, as measured using GPC-FTIR, the distribution is described as "normal." The term "normal comonomer distribution" is used herein to mean that the comonomer content of various polymer fractions across the molecular weight range of the first polyethylene is not substantially uniform, with higher molecular weight fractions having proportionally lower comonomer contents. If the comonomer incorporation is approximately constant with molecular weight, as measured using GPC-FTIR, the comonomer distribution is described as "flat" or "uniform." The terms "inverse comonomer distribution" and "partially inverse comonomer distribution" refer to the presence of one or more high molecular weight components with higher comonomer incorporation than one or more low molecular weight components in GPC-FTIR data obtained for the copolymer. The term "reverse comonomer distribution" is used herein to mean that the comonomer content of the various polymer fractions across the molecular weight range of the first polyethylene is not substantially uniform, with the higher molecular weight fractions having proportionally higher comonomer content (i.e., if comonomer incorporation increases with molecular weight, the distribution is described as "reverse" or "reversed"). If comonomer incorporation increases and then decreases with increasing molecular weight, the comonomer distribution is still considered "reverse," but may be described as "partially reversed."

[0083] In one embodiment, the first polyethylene contains catalyst residues that reflect the chemical composition of the catalyst formulation used to make it. Those skilled in the art will understand that catalyst residues are typically quantified in terms of parts per million of metal, for example, in the first polyethylene, where the metals present originate from the metals in the catalyst formulation used to make it. Non-limiting examples of metal residues that may be present include Group 4 to 6 metals, such as titanium, zirconium, hafnium, and vanadium.

[0084] In embodiments of the present disclosure, the first polyethylene has (based on the weight of the first polyethylene) at least 0.050 ppm titanium, or at least 0.100 ppm titanium, or at least 0.250 ppm titanium, or at least 0.300 ppm titanium.

[0085] In an embodiment of the present disclosure, the first polyethylene has (based on the weight of the first polyethylene) 0.050 to 3.0 ppm titanium, or 0.050 to 2.5 ppm titanium, or 0.050 to 2.0 ppm titanium, or 0.050 to 1.5 ppm titanium, or 0.050 to 1.0 ppm titanium, or 0.100 to 3.0 ppm titanium, or 0.100 to 2.5 ppm titanium, or 0.100 to 2.0 ppm titanium, or 0.100 to 1.5 ppm titanium, or 0.100 to 1.0 ppm titanium, or 0.250 to 3.0 ppm titanium, or 0.250 to 2.0 ppm titanium, or 0.250 to 1.5 ppm titanium, or 0.250 to 1.0 ppm titanium.

[0086] In embodiments of the present disclosure, the first polyethylene has at least 0.050 ppm vanadium, or at least 0.100 ppm vanadium, or at least 0.200 ppm vanadium, or at least 0.250 ppm vanadium, or at least 0.300 ppm vanadium (based on the weight of the first polyethylene).

[0087] In an embodiment of the present disclosure, the first polyethylene contains (by weight of the first polyethylene) 0.050 to 3.0 ppm vanadium, or 0.050 to 2.5 ppm vanadium, or 0.050 to 2.0 ppm vanadium, or 0.050 to 1.5 ppm vanadium, or 0.050 to 1.0 ppm vanadium, or 0.100 to 3.0 ppm vanadium, or 0 It has 0.100 to 2.5 ppm of vanadium, or 0.100 to 2.0 ppm of vanadium, or 0.100 to 1.5 ppm of vanadium, or 0.100 to 1.0 ppm of vanadium, or 0.200 to 3.0 ppm of vanadium, or 0.200 to 2.0 ppm of vanadium, or 0.200 to 1.5 ppm of vanadium, or 0.200 to 1.0 ppm of vanadium.

[0088] In one embodiment of the present disclosure, the first polyethylene has no long chain branching or does not contain measurable amounts of long chain branching ("LCB"). LCB is a well-known structural phenomenon in ethylene copolymers and is well known to those skilled in the art. Traditionally, there are three methods for LCB analysis: nuclear magnetic resonance spectroscopy (NMR) (see, e.g., J.C.Randall, J. Macromol. Sci. Rev. Macromol. Chem. Phys., 1989, Vol. 29, p. 201); triple-detection SEC with DRI, viscometer, and low-angle laser light scattering detector (see, e.g., W.W. Yau and D.R. Hill, Int. J. Polym. Anal. Character., 1996, Vol. 2, p. 151); and rheology (see, e.g., W.W. Graessley, Acc. Chem. Res., 1977, Vol. 10, pp. 332-339).

[0089] In one embodiment of the present disclosure, a first polyethylene is produced characterized by having an Mz greater than about 500,000, a molecular weight distribution (Mw / Mn) of about 9.0 to about 12.0, and a melt index greater than 0.5 g / 10 min. Without wishing to be bound by theory, we have observed that these first polyethylene properties can be achieved using the multi-zone reactor system described above and by carefully manipulating the amount and location of hydrogen addition throughout the multi-zone reactor system, as shown in the accompanying examples.

[0090] <Second polyethylene> In the present disclosure, the second polyethylene comprises a nucleating agent or a mixture of nucleating agents.

[0091] In an embodiment of the present disclosure, the second polyethylene has a viscosity of at least 0.950 g / cm 3 It is a high density polyethylene having a density of

[0092] In this disclosure, high density polyethylene (HDPE) has a density of at least 0.950 g / cm 3 is defined as an ethylene homopolymer or ethylene copolymer having a density of

[0093] In one embodiment of the present disclosure, the high density polyethylene (HDPE) comprises one or more nucleating agents.

[0094] In an embodiment of the present disclosure, the second polyethylene is a polyethylene homopolymer composition comprising one or more ethylene homopolymer components.

[0095] In an embodiment of the present disclosure, the second polyethylene has a viscosity of at least 0.950 g / cm 3 It is a polyethylene homopolymer composition having a density of

[0096] In an embodiment of the present disclosure, the second polyethylene is a polyethylene homopolymer composition comprising a first ethylene homopolymer and a second ethylene homopolymer, embodiments of the first ethylene homopolymer and the second ethylene homopolymer are further described below.

[0097] In one embodiment of the present disclosure, the polyethylene homopolymer composition has a bimodal profile in a gel permeation chromatograph. In one embodiment of the present disclosure, the polyethylene homopolymer composition has a multimodal profile in a gel permeation chromatograph.

[0098] In one embodiment of the present disclosure, the polyethylene homopolymer composition comprises one or more nucleating agents.

[0099] In an embodiment of the present disclosure, the polyethylene homopolymer composition has a viscosity of at least 0.950 grams per cubic centimeter (g / cm 3 ), or at least 0.955 grams per cubic centimeter (g / cm 3 ), or at least 0.960 grams per cubic centimeter (g / cm 3 ) density. In an embodiment of the present disclosure, the polyethylene homopolymer composition has a viscosity of 0.950 to 0.975 g / cm 3 , or 0.952 to 0.975 g / cm 3 , or 0.952 to 0.973 g / cm 3 , or 0.955 to 0.975 g / cm 3 , or 0.955 to 0.970 g / cm 3 It has a density of

[0100] In an embodiment of the present disclosure, the polyethylene homopolymer composition has a melt index I2 of 0.5 to 10.0 g / 10 min, or 0.5 to 5.0 g / 10 min. In a further embodiment of the present disclosure, the polyethylene homopolymer composition has a melt index I2 of 0.8 to 8.0 g / 10 min, or 0.8 to 5 g / 10 min.

[0101] In one embodiment of the present disclosure, the polyethylene homopolymer composition has a molecular weight distribution (Mw / Mn) of about 3.0 to about 20.0.

[0102] The polyethylene homopolymer composition can be made by any blending process, such as: 1) physical blending of particulate resins; 2) co-feeding different resins into a common extruder; 3) melt mixing (in any conventional polymer mixing equipment); 4) solution blending; or 5) a polymerization process using two or more reactors.

[0103] In one embodiment of the present disclosure, the polyethylene homopolymer composition is prepared by a solution polymerization process using two reactors operating under different polymerization conditions, which results in a homogeneous in-situ blend of the first and second ethylene homopolymer components. An example of this process is described in published U.S. Patent Application Publication No. 2006 / 0047078, the disclosure of which is incorporated herein by reference.

[0104] In one embodiment of the present disclosure, the polyethylene homopolymer composition is prepared by melt blending the first and second ethylene homopolymers in an extruder.

[0105] In one embodiment of the present disclosure, the polyethylene homopolymer composition is prepared by melt blending in an extruder the following two blend components: 90 to 70% by weight of (I) a first ethylene homopolymer having a melt index I2 of about 0.8 to about 2.0 grams / 10 minutes and a melt index I3 of 0.955 to 0.965 g / cm 3 a first ethylene homopolymer which is a conventional polyethylene homopolymer composition (HDPE) having a density of 10 to 30 wt. % of (II) a second ethylene homopolymer having a melt index I2 of about 15 to about 30 grams / 10 minutes and a melt index I3 of 0.950 to 0.960 g / cm 3 a first ethylene homopolymer which is a conventional polyethylene homopolymer composition (HDPE) having a density of

[0106] In one embodiment of the present disclosure, a polyethylene homopolymer composition is prepared by a solution polymerization process using two reactors operating under different polymerization conditions, resulting in a uniform in-situ blend of the ethylene polymer components produced in each reactor. Such a blend can be prepared, for example, according to U.S. Patent Application Publication Nos. 2013 / 0225743 or 2008 / 0118749, and U.S. Provisional Application No. 63 / 023,270.

[0107] In one embodiment, the polyethylene homopolymer composition is an in-situ blend of a first ethylene homopolymer and a second ethylene homopolymer.

[0108] <First ethylene homopolymer> In one embodiment, the first ethylene homopolymer is made using a single-site catalyst. In one embodiment, the first ethylene homopolymer is made using a phosphinimine catalyst. In one embodiment, the first ethylene homopolymer is made in a solution phase polymerization reactor using a single-site catalyst. In one embodiment, the first ethylene homopolymer is made in a solution phase polymerization reactor using a phosphinimine catalyst.

[0109] In one embodiment of the present disclosure, the first ethylene homopolymer has a melt index I2 lower than the melt index I2 of the second ethylene homopolymer. In one embodiment of the present disclosure, the first ethylene homopolymer has a melt index I2 that is at least 50% less than the melt index I2 of the second ethylene homopolymer. In one embodiment of the present disclosure, the first ethylene homopolymer has a melt index I2 that is at least 10 times less than the melt index I2 of the second ethylene homopolymer.

[0110] In one embodiment of the present disclosure, the first ethylene homopolymer has a weight average molecular weight M w Higher weight average molecular weight M w It has.

[0111] As will be appreciated by those skilled in the art, melt index I2 is generally inversely proportional to molecular weight. Thus, in one embodiment of the present disclosure, the first ethylene homopolymer has a relatively low melt index I2 (or, in other words, a relatively high molecular weight) compared to the second ethylene homopolymer.

[0112] In one embodiment of the present disclosure, the first ethylene homopolymer has a viscosity of 0.950 to 0.975 g / cm 3 In another embodiment of the present disclosure, the first ethylene homopolymer has a density of 0.955 to 0.970 g / cm 3 In another embodiment of the present disclosure, the first ethylene homopolymer has a density of 0.955 to 0.965 g / cm 3 It has a density of

[0113] In one embodiment of the present disclosure, the first ethylene homopolymer has a melt index I2 of about 0.01 to about 1.0 grams / 10 minutes (g / 10 min). In one embodiment of the present disclosure, the first ethylene homopolymer has a melt index I2 of about 0.1 to about 2.0 grams / 10 minutes (g / 10 min). In an embodiment of the present disclosure, the first ethylene homopolymer has a melt index I2 of from about 0.1 to about 5.0 grams per 10 minutes (g / 10 min), or from about 0.1 to about 10 grams per 10 min.

[0114] In one embodiment of the present disclosure, the molecular weight distribution (Mw / Mn) of the first ethylene homopolymer is from about 1.7 to about 20.0. In further embodiments of the present disclosure, the molecular weight distribution (Mw / Mn) of the first ethylene homopolymer is from about 2.0 to about 20.0, or from about 1.7 to about 4.0, or from about 2.0 to about 4.0.

[0115] In one embodiment of the present disclosure, the first ethylene homopolymer may itself comprise one or more high density ethylene homopolymer subcomponents.

[0116] In one embodiment of the present disclosure, the first ethylene homopolymer comprises 95 to 30 wt% of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the first ethylene homopolymer comprises 95 to 40 wt% of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the first ethylene homopolymer comprises 95 to 50 wt% of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the first ethylene homopolymer comprises 95 to 60 wt% of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the first ethylene homopolymer comprises 90 to 30 wt% of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the first ethylene homopolymer comprises 90 to 40 wt% of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the first ethylene homopolymer comprises 90 to 50 weight percent (wt%) of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the first ethylene homopolymer comprises 90 to 60 weight percent (wt%) of the total weight of the first and second ethylene homopolymers.

[0117] In one embodiment of the present disclosure, the first ethylene homopolymer constitutes 75 to 35 wt% of the total weight of the first and second ethylene homopolymers, or the first ethylene homopolymer constitutes 65 to 40 wt% of the total weight of the first and second ethylene homopolymers, or the first ethylene homopolymer constitutes 65 to 45 wt% of the total weight of the first and second ethylene homopolymers, or the first ethylene homopolymer constitutes 65 to 50 wt% of the total weight of the first and second ethylene homopolymers, or the first ethylene homopolymer constitutes 60 to 50 wt% of the total weight of the first and second ethylene homopolymers.

[0118] <Second ethylene homopolymer> In one embodiment, the second ethylene homopolymer is made using a single-site catalyst. In one embodiment, the second ethylene homopolymer is made using a phosphinimine catalyst. In one embodiment, the second ethylene homopolymer is made in a solution phase polymerization reactor using a single-site catalyst. In one embodiment, the second ethylene homopolymer is made in a solution phase polymerization reactor using a phosphinimine catalyst.

[0119] In one embodiment of the present disclosure, the second ethylene homopolymer has a melt index I2 higher than the melt index I2 of the first ethylene homopolymer. In one embodiment of the present disclosure, the second ethylene homopolymer has a melt index I2 that is at least 50% greater than the melt index I2 of the first ethylene homopolymer. In one embodiment of the present disclosure, the second ethylene homopolymer has a melt index I2 that is at least 10 times greater than the melt index I2 of the first ethylene homopolymer.

[0120] In one embodiment of the present disclosure, the second ethylene homopolymer has a weight average molecular weight M w Weight average molecular weight M w It has.

[0121] As will be appreciated by those skilled in the art, melt index I2 is generally inversely proportional to molecular weight. Thus, in one embodiment of the present disclosure, the second ethylene homopolymer has a relatively high melt index I2 (or, in other words, a relatively low molecular weight) compared to the first ethylene homopolymer.

[0122] In one embodiment of the present disclosure, the second ethylene homopolymer has a viscosity of 0.950 to 0.975 g / cm 3In another embodiment of the present disclosure, the second ethylene homopolymer has a density of 0.955 to 0.970 g / cm 3 In another embodiment of the present disclosure, the second ethylene homopolymer has a density of 0.955 to 0.965 g / cm 3 It has a density of

[0123] In one embodiment of the present disclosure, the second ethylene homopolymer has a melt index I2 greater than about 100 g / 10 min, or greater than about 250 g / 10 min, or greater than about 500 g / 10 min. In further embodiments, the second ethylene homopolymer may have a melt index I2 greater than about 500 to about 25,000 g / 10 min, or greater than about 500 to about 15,000 g / 10 min, or greater than about 500 to about 10,000 g / 10 min, or greater than about 500 to about 8,500 g / 10 min.

[0124] In further embodiments, the second ethylene homopolymer may have a melt index of greater than about 5.0 to about 50 g / 10 min, or greater than about 5.0 to about 40.0 g / 10 min, or greater than about 5.0 to about 30 g / 10 min, or greater than about 5.0 to about 20.0 g / 10 min.

[0125] In one embodiment of the present disclosure, the molecular weight distribution (Mw / Mn) of the second ethylene homopolymer is from about 1.7 to about 20.0. In further embodiments of the present disclosure, the molecular weight distribution (Mw / Mn) of the second ethylene homopolymer is from about 2.0 to about 20.0, or from about 1.7 to about 4.0, or from about 2.0 to about 4.0.

[0126] In one embodiment of the present disclosure, the second ethylene homopolymer may itself comprise one or more high density ethylene homopolymer minor components.

[0127] In one embodiment of the present disclosure, the second ethylene homopolymer comprises 5 to 70 wt% (wt%) of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the second ethylene homopolymer comprises 5 to 60 wt% (wt%) of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the second ethylene homopolymer comprises 5 to 50 wt% (wt%) of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the second ethylene homopolymer comprises 5 to 40 wt% (wt%) of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the second ethylene homopolymer comprises 10 to 70 wt% (wt%) of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the second ethylene homopolymer comprises 10 to 60 wt% (wt%) of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the second ethylene homopolymer comprises 10 to 50 wt% of the total weight of the first and second ethylene homopolymers. In one embodiment of the present disclosure, the second ethylene homopolymer comprises 10 to 40 wt% of the total weight of the first and second ethylene homopolymers.

[0128] In one embodiment of the present disclosure, the second ethylene homopolymer constitutes 25% to 65% by weight (wt%) of the total weight of the first and second ethylene homopolymers, or the second ethylene homopolymer constitutes 35% to 60% by weight (wt%) of the total weight of the first and second ethylene homopolymers, or the second ethylene homopolymer constitutes 35 to 55% by weight (wt%) of the total weight of the first and second ethylene homopolymers, or the second ethylene homopolymer constitutes 35 to 50% by weight (wt%) of the total weight of the first and second ethylene homopolymers, or the second ethylene homopolymer constitutes 40 to 50% by weight (wt%) of the total weight of the first and second ethylene homopolymers.

[0129] <Nucleating agent> The term "nucleating agent" as used herein is intended to convey its conventional meaning to those skilled in the art of preparing nucleated polyolefin compositions, namely, an additive that alters the crystallization behavior of a polymer as the polymer melt cools.

[0130] A review of nucleating agents is provided in US Pat. Nos. 5,981,636, 6,465,551 and 6,599,971, the disclosures of which are incorporated herein by reference.

[0131] A nucleating agent that is commercially available and can be added to the second polyethylene (eg, high density polyethylene or polyethylene homopolymer composition) is dibenzylidene sorbital ester. Further examples of nucleating agents that can be added to the second polyethylene include the cyclic organic structures disclosed in U.S. Pat. No. 5,981,636 (and salts thereof, such as disodium bicyclo[2.2.1]heptenedicarboxylate); saturated versions of the structures disclosed in U.S. Pat. No. 5,981,636 (such as those disclosed in U.S. Pat. No. 6,465,551; Zhao et al. to Milliken); salts of certain cyclic dicarboxylic acids having a hexahydrophthalic acid structure (or "HHPA" structure) disclosed in U.S. Pat. No. 6,599,971 (Dotson et al. to Milliken); and cyclic dicarboxylic acid salts and salts thereof, such as phosphate esters such as those disclosed in U.S. Pat. No. 5,342,868 and sold by Asahi Denka Kogyo under the trade names NA-11 and NA-21, and divalent metal or metalloid salts (especially calcium salts) of the HHPA structure disclosed in U.S. Pat. No. 6,599,971. For clarity, the HHPA structure includes a ring structure having six carbon atoms in the ring and two carboxylic acid groups that are substituents on adjacent atoms of the ring structure. The other four carbon atoms in the ring may be substituted, as disclosed in U.S. Pat. No. 6,599,971. One example is calcium 1,2-cyclohexanedicarboxylic acid (CAS Registry Number 491589-22-1). Further examples of nucleating agents that can be added to the second polyethylene include those disclosed in WO 2015 / 042561, WO 2015 / 042563, WO 2015 / 042562, and WO 2011 / 050042.

[0132] Another nucleating agent that is commercially available and that can be added to the second polyethylene in one embodiment of the present disclosure is talc (sold as MICROTUFF® AG609).

[0133] A nucleating agent that is commercially available and that can be added to the second polyethylene in one embodiment of the present disclosure is IRGASTAB® NA287. A nucleating agent that is commercially available and that can be added to the second polyethylene in one embodiment of the present disclosure is HPN® 210M.

[0134] Many of the nucleating agents mentioned above can be difficult to mix with the second polyethylene to be nucleated, and it is known to use dispersing aids such as zinc stearate to alleviate this problem.

[0135] In one embodiment of the present disclosure, the nucleating agent is well dispersed in the second polyethylene.

[0136] In one embodiment of the present disclosure, the amount of nucleating agent used is relatively small, between 100 and 3000 ppm by weight (based on the weight of the polymer), and those skilled in the art will appreciate that some care should be taken to ensure good dispersion of the nucleating agent. In one embodiment of the present disclosure, the nucleating agent is added to the second polyethylene in a finely divided form (less than 50 microns, particularly less than 10 microns) to facilitate mixing. This type of "physical blend" (i.e., a mixture of the nucleating agent in solid form with the resin) is, in some embodiments, preferable to using a "masterbatch" of the nucleating agent (where the term "masterbatch" refers to an embodiment in which the additive (in this case, the nucleating agent) is first melt-mixed with a small amount of the second polyethylene and then the "masterbatch" is melt-mixed with the remaining bulk of the second polyethylene).

[0137] In one embodiment of the present disclosure, additives such as nucleating agents may be added to the second polyethylene by means of a "masterbatch," where the term "masterbatch" refers to an embodiment in which the additive (e.g., nucleating agent) is first melt-mixed with a small amount of the second polyethylene, and then the "masterbatch" is melt-mixed with the remaining bulk of the second polyethylene.

[0138] In one embodiment of the present disclosure, the second polyethylene comprises a nucleating agent or a mixture of nucleating agents.

[0139] In one embodiment of the present disclosure, the nucleating agent or mixture of nucleating agents comprises a salt of a dicarboxylic acid.

[0140] In one embodiment, the nucleating agent or mixture of nucleating agents comprises 1,2-cyclohexanedicarboxylic acid (CAS Registry Number 491589-22-1) as a calcium salt.

[0141] In one embodiment, the nucleating agent, or mixture of nucleating agents, is 1,2-cyclohexanedicarboxylic acid (CAS Registry Number 491589-22-1) as a calcium salt mixed with zinc stearate.

[0142] In embodiments, the nucleating agent or mixture of nucleating agents is added in an amount of 50 to 5,000 ppm, or 100 to 4,000 ppm, or 200 to 4,000 ppm, or 100 to 3,000 ppm, or 200 to 3,000 ppm, or 100 to 2,000 ppm, or 200 to 2,000 ppm, or 500 to 5,000 ppm, or 500 to 4,000 ppm, or 500 to 3,000 ppm, or 500 to 2,000 ppm, or 500 to 1,500 ppm, based on the weight of the second polyethylene.

[0143] <Third Polyethylene> In an embodiment of the present disclosure, the third polyethylene has a lower density than the first polyethylene.

[0144] In one embodiment of the present disclosure, the third polyethylene is an ethylene copolymer.

[0145] In an embodiment of the present disclosure, the third polyethylene is selected from the group consisting of linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), very low density polyethylene (VLDPE), and high pressure low density polyethylene (HPLDPE) prepared by free radical polymerization of ethylene.

[0146] In an embodiment of the present disclosure, the third polyethylene is selected from the group consisting of linear low density polyethylene (LLDPE) and medium density polyethylene (MDPE).

[0147] In an embodiment of the present disclosure, the third polyethylene is a polymer blend comprising two or more polymer blend components selected from the group consisting of linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), very low density polyethylene (VLDPE), and high pressure low density polyethylene (HPLDPE) prepared by free radical polymerization of ethylene.

[0148] <Very low density polyethylene (VLDPE)> As used herein, the terms "very low density polyethylene" and "VLDPE" refer to a density of about 0.910 g / cm 3 Less than, or about 0.910 g / cm 3 refers to an ethylene copolymer having a density of

[0149] Ultra-low density polyethylene includes plastomers and elastomers.

[0150] In an embodiment, the VLDPE has a viscosity of about 0.870 g / cm 3 ~Approx. 0.910g / cm 3 , or about 0.880 g / cm 3 ~Approx. 0.910g / cm 3 , or about 0.890 to about 910 g / cm 3 It has a density of

[0151] In one embodiment of the present disclosure, the VLDPE is an ethylene copolymer comprising, as polymerizable monomers, ethylene and an alpha-olefin selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene, and mixtures thereof. In one embodiment of the present disclosure, the VLDPE is an ethylene copolymer that includes ethylene and 1-octene as polymerizable monomers.

[0152] In an embodiment of the present disclosure, the VLDPE has a melt index I2 of about 0.5 to about 20 g / 10 min, or about 0.5 to 10 g / 10 min.

[0153] In an embodiment, the VLDPE may be a homogeneously branched polyethylene. In an embodiment, the VLDPE may be a heterogeneously branched polyethylene.

[0154] In one embodiment of the present disclosure, the VLDPE is made using a multi-site catalyst. In one embodiment of the present disclosure, the VLDPE is made using a Ziegler-Natta catalyst. In one embodiment of the present disclosure, the VLDPE is made using a single-site catalyst. In embodiments of the present disclosure, the VLDPE is made using a metallocene catalyst, a phosphinimine catalyst, or a constrained geometry catalyst. In one embodiment of the present disclosure, the VLDPE is made using a Ziegler-Natta catalyst in a solution phase polymerization process. In one embodiment of the present disclosure, the VLDPE is produced using a single-site catalyst in a solution phase polymerization process.

[0155] In embodiments of the present disclosure, the VLPDE has a melt index (I2) of 0.1 to 10 g / 10 min, or 0.9 to 2.3 g / 10 min, and a melt index (I2) of about 0.890 to about 0.910 g / cm 3 It has a density of

[0156] <Linear low-density polyethylene (LLDPE)> As used herein, the terms "linear low density polyethylene" and "LLDPE" refer to a linear low density polyethylene having a density of about 0.910 g / cm 3 ~Approx. 0.935g / cm 3 refers to a polyethylene homopolymer or copolymer having a density of

[0157] In one embodiment, the LLDPE is a linear polymer containing minimal or relatively low, or even undetectable, amounts of long chain branching.

[0158] In one embodiment, the LLDPE may contain long chain branching.

[0159] As used herein, "long-chain branching" refers to branches having a chain length longer than short-chain branches, resulting from the incorporation of comonomers. In embodiments, long-chain branches may be approximately the same length as the polymer backbone, or may be the same length. Long-chain branching (LCB) can be determined by conventional techniques known in the art, such as C nuclear magnetic resonance (C NMR) spectroscopy, and can be quantified, for example, using the method of Randall (Rev. Macromol. Chem. Phys., C29(2&3), pp. 285-297). Two other methods that can be used include gel permeation chromatography coupled with a low-angle laser light scattering detector (GPC-LALLS) and gel permeation chromatography coupled with a differential viscometer detector (GPC-DV). The use of these techniques for long-chain branching detection and the underlying theory are well documented in the literature. See, for example, Zimm, BH and Stockmayer, WH, J. Chem. Phys., 17, 1301 (1949) and Rudin A., Modern Methods of Polymer Characterization, John Wiley & Sons, New York (1991), 103-112.

[0160] In embodiments, the linear low density polyethylene may be substituted, on average, in the range of from 0.001 long chain branches / 10,000 carbons to 3 long chain branches / 10,000 carbons, from 0.001 long chain branches / 10,000 carbons to 1 long chain branch / 10,000 carbons, from 0.05 long chain branches / 10,000 carbons to 1 long chain branch / 10,000 carbons.

[0161] In other embodiments, the linear low density polyethylene is substituted with an average of less than 1 long chain branch / 10,000 carbons, less than 0.5 long chain branches / 10,000 carbons, or less than 0.05 long chain branches / 10,000 carbons, or less than 0.01 long chain branches / 10,000 carbons.

[0162] In one embodiment of the present disclosure, the LLDPE is an ethylene copolymer.

[0163] In an embodiment, the LLDPE is an ethylene / alpha olefin copolymer, wherein at least 50% by weight of the ethylene copolymer is polymerized ethylene. In a further embodiment, the LLDPE is an ethylene / alpha olefin copolymer, wherein at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95% by weight of the ethylene copolymer is polymerized ethylene.

[0164] In an embodiment of the present disclosure, the LLDPE is an ethylene / alpha-olefin copolymer containing, by molar ratio, less than 15%, or less than 10%, or less than 8%, or less than 7%, or less than 5%, or less than 4%, or less than 3% of units derived from one or more alpha-olefin comonomers.

[0165] In an embodiment of the present disclosure, the LLDPE is an ethylene / alpha-olefin copolymer containing, in a molar ratio, 0.5-15%, or 0.5-12%, or 0.5-10%, or 0.5-8%, or 0.5-5%, or 0.5-3%, or 1-12%, or 1-10%, or 1-8%, or 1-5%, or 2-12%, or 2-10%, or 2-8%, or 2-5%, or 3-12%, or 3-10%, or 3-7% of units derived from one or more alpha-olefin comonomers.

[0166] In one embodiment of the present disclosure, the LLDPE is an ethylene copolymer comprising, as polymerizable monomers, ethylene and an alpha-olefin selected from the group consisting of 1-butene, 1-hexene, 1-octene, and mixtures thereof. In one embodiment of the present disclosure, the LLDPE is an ethylene copolymer comprising ethylene and 1-butene as polymerizable monomers. In one embodiment of the present disclosure, the LLDPE is an ethylene copolymer containing ethylene and 1-hexene as polymerizable monomers. In one embodiment of the present disclosure, the LLDPE is an ethylene copolymer comprising ethylene and 1-octene as polymerizable monomers. In one embodiment of the present disclosure, the LLDPE is an ethylene copolymer comprising ethylene and 1-octene as polymerized monomers.

[0167] In one embodiment, the LLDPE has a viscosity of about 0.910 g / cm 3 ~Approx. 0.935g / cm 3 In an embodiment of the present disclosure, the LLDPE has a density of about 0.910 g / cm 3 , or about 0.912 g / cm 3 , or about 0.915 g / cm 3 , or about 0.916 g / cm 3 , or about 0.917 g / cm 3 , or about 0.918 g / cm 3 From a low density of about 0.927 g / cm 3 , or about 0.930 g / cm 3 , or about 0.932 g / cm 3 , or about 0.935 g / cm 3 In an embodiment of the present disclosure, the LLDPE has a density ranging from about 0.910 g / cm 3 ~Approx. 0.935g / cm 3 , or approximately 0.910 to 0.932 g / cm 3 , or about 0.912 g / cm 3 ~Approx. 0.935g / cm 3 , or about 0.912 to about 0.932 g / cm 3 , or about 0.915 g / cm 3 ~Approx. 0.935g / cm 3 , or about 0.915 g / cm 3 ~Approx. 0.932g / cm 3 , or about 0.915 to about 0.930 g / cm 3, or about 0.916 to about 0.935 g / cm 3 , or about 0.916 to about 0.932 g / cm 3 , or about 0.916 to about 0.930 g / cm 3 , or about 0.915 to about 0.927 g / cm 3 , or about 0.915 to about 0.925 g / cm 3 , or about 0.916 to about 0.924 g / cm 3 , or about 0.920 to about 0.935 g / cm 3 , or about 0.920 to about 0.932 g / cm 3 It has a density of

[0168] In one embodiment of the present disclosure, the LLDPE has a molecular weight distribution (Mw / Mn) of 10.0 or less. In further embodiments of the present disclosure, the LLDPE has a molecular weight distribution (Mw / Mn) of 9.0 or less, 8.0 or less, 7.0 or less, or 6.0 or less.

[0169] In one embodiment of the present disclosure, the LLDPE has a molecular weight distribution (Mw / Mn) of about 1.6 to about 6.0.

[0170] In an embodiment of the present disclosure, the LLDPE has a molecular weight distribution (Mw / Mn) ranging from a low molecular weight of about 1.6, or about 1.7, or about 2.0, or about 2.5, or about 3.0, or about 3.5, to a high molecular weight of about 4.5, or about 5.0, or about 5.25, or about 5.5, or about 6.0. In an embodiment of the present disclosure, the LLDPE has a viscosity of from about 1.7 to about 5.5, or from about 1.7 to about 5.0, or from about 1.7 to about 4.5, or from about 1.7 to about 4.0, or from about 1.8 to about 3.5, or from about 2.0 to about 3.0, or from about 2.0 to about 10.0, or from about 2.0 to about 9.0, or from 2.0 to about 8.0, or from about 2.0 to about 7.0, or from about 2.0 to about 6.0, or from about 2.0 to about 5.0, or from about 2.0 to about 4.0, or from about 2.0 to about 3.5, or from about 2.5 to about 5.0. The molecular weight distribution (Mw / Mn) is about 10.0, or about 2.5 to about 9.0, or 2.5 to about 8.0, or about 2.5 to about 7.0, or about 2.5 to about 6.0, or about 2.5 to about 5.0, or about 2.5 to about 4.0, or about 2.5 to about 3.5; or about 3.0 to about 10.0, or about 3.0 to about 9.0, or about 3.0 to about 8.0, or about 3.0 to about 7.0, or about 3.0 to about 6.0, or about 3.0 to about 5.0, or about 3.0 to about 4.0.

[0171] In some embodiments, the LLDPE can have a Z-average molecular weight distribution, Mz / Mw, ratio of 1.5 to 6.0, including all values ​​and subranges subsumed within this range. For example, in further embodiments, the LLDPE can have a Z-average molecular weight distribution, Mz / Mw, from a lower limit of 1.5, or 1.75, or 2.0, or 2.5, or 2.75, or 3.0, or 3.5, to an upper limit of 2.0, or 2.5, or 3.0, or 3.5, or 4.0, or 4.5, or 5.0, or 5.5, or 6.0. In some embodiments, the LLDPE has a Z-average molecular weight distribution, Mz / Mw, ratio of 1.5 to 5.5, or 1.5 to 5.0, or 1.5 to 4.0, or 1.5 to 3.5, or 1.5 to 3.0, or 1.5 to 2.5.

[0172] In embodiments of the present disclosure, the LLDPE may be unimodal, bimodal, or multimodal in gel permeation chromatography (GPC) analysis. The term "unimodal" is defined herein to mean the presence of only one clear, significant peak or maximum in a molecular weight distribution curve generated according to the method of ASTM D6474-99. In contrast, use of the term "bimodal" is meant to convey the presence of a second peak or shoulder representing a higher or lower molecular weight component in addition to the first peak (i.e., the molecular weight distribution can be said to have two maxima in the molecular weight distribution curve). Alternatively, the term "bimodal" refers to the presence of two maxima in a molecular weight distribution curve generated according to the method of ASTM D6474-99. The term "multimodal" refers to the presence of two or more, typically more than two, maxima in a molecular weight distribution curve generated according to the method of ASTM D6474-99.

[0173] In one embodiment of the present disclosure, the LLDPE has a melt index (I2) of about 0.1 g / 10 min to about 20 g / 10 min. In an embodiment of the present disclosure, the LLDPE has a melt index (I2) in the range of about 0.75 g / 10 min to about 15 g / 10 min, or about 0.85 g / 10 min to about 10 g / 10 min, or about 0.9 g / 10 min to about 8 g / 10 min. In embodiments of the present disclosure, the LLDPE has a melt index (I2) ranging from a low melt index of about 0.20 g / 10 min, or about 0.25 g / 10 min, or about 0.5 g / 10 min, or about 0.75 g / 10 min, or about 1 g / 10 min, or about 2 g / 10 min, to a high melt index of about 3 g / 10 min, or about 4 g / 10 min, or about 5 g / 10 min, or about 10 g / 10 min.

[0174] In an embodiment of the present disclosure, the LLDPE has a melt index (I2) of 0.1 to 10 g / 10 min, or 0.5 to 10.0 g / 10 min, or 0.5 to 5.0 g / 10 min, or 0.8 to 5.0 g / 10 min, or 0.8 to 10 g / 10 min.

[0175] In an embodiment of the present disclosure, the LLDPE has a melt index (I2) of from about 0.75 g / 10 min to about 6 g / 10 min, or from about 1 g / 10 min to about 8 g / 10 min, or from about 0.8 g / 10 min to about 6 g / 10 min, or from about 1 g / 10 min to about 4.5 g / 10 min, or from about 0.20 g / 10 min to about 5.0 g / 10 min, or from about 0.30 g / 10 min to about 5.0 g / 10 min, or from about 0.40 g / 10 min to about 5.0 g / 10 min, or from about 0.50 g / 10 min to about 5.0 g / 10 min, or from about 0.5 to 2.5 g / 10 min, or from about 0.5 to 2.0 g / 10 min.

[0176] In an embodiment of the present disclosure, the LLDPE has a melt flow ratio I of 20 to 80. 21 For example, in a further embodiment, the LLDPE may have a melt index ratio I / I2 of 20 to 75, or 20 to 70, or 20 to 65, or 20 to 60, or 20 to 55, or 20 to 50, or 25 to 75, or 25 to 70, or 25 to 65, or 25 to 60, or 25 to 55, or 25 to 50, or 30 to 80, or 30 to 75, or 30 to 70, or 30 to 65, or 30 to 60, or 30 to 55, or 30 to 50, or 35 to 80, or 35 to 75, or 35 to 70, or 35 to 65, or 35 to 60, or 35 to 55 g / 10 min. 21 / I2.

[0177] In other embodiments, the LLDPE has a melt flow ratio I less than 50, less than 47, less than 45, less than 42, less than 40, less than 35, or less than 30. 21 In a further embodiment, the LLDPE may have a melt index ratio I / I2 of 20 to 40, or 20 to 37, or 22 to 37, or 22 to 35, or 25 to 35, or 25 to 30. 21 / I2.

[0178] In an embodiment of the present disclosure, the LLDPE has a melt flow ratio (I) of less than about 36, or less than about 35, or less than about 32, or less than about 30, or less than about 28, or less than about 26, or less than about 24, or less than about 22, or less than about 20. 21In an embodiment of the present disclosure, the LLDPE has a melt flow ratio (I / I2) of from about 16 to about 36, or from about 16 to about 35, or from about 16 to about 32, or from about 16 to about 30, or from about 18 to about 35, or from about 18 to about 32, or from about 18 to about 30, or from about 16 to about 27, or from about 16 to about 25, or from about 16 to about 22, or from about 16 to about 20. 21 / I2).

[0179] In one embodiment of the present disclosure, the LLDPE has greater than or equal to about 50% by weight CBDI as determined by TREF analysis. 50 or about 50% by weight or less of CBDI 50 It has.

[0180] In an embodiment of the present disclosure, the LLDPE has a composition distribution breadth index (CDBI) of from about 25 wt. % to about 95 wt. %, or from about 35 wt. % to about 90 wt. %, or from about 40 wt. % to about 85 wt. %, or from about 40 wt. % to about 80 wt. %, as determined by temperature elution fractionation (TREF). 50 It has.

[0181] In embodiments of the present disclosure, the LLDPE can be produced using a gas phase polymerization process, a solution phase polymerization process, or a slurry phase polymerization process, or any combination thereof, using any type of reactor or reactor configuration known in the art (e.g., fluidized bed gas phase reactors, loop reactors, stirred tank reactors, batch reactors, etc.; and reactors can be connected in series or parallel, and any combination thereof).

[0182] In an embodiment of the present disclosure, the LLDPE has a melt index (I2) of 0.1 to 10 g / 10 min, or 0.9 to 2.3 g / 10 min, and a melt index (I2) of about 0.910 to about 0.935 g / cm 3 It has a density of

[0183] In an embodiment, the LLDPE may be a homogeneously branched polyethylene. In an embodiment, the LLDPE may be a heterogeneously branched polyethylene.

[0184] In one embodiment of the present disclosure, the LLDPE is made using a multi-site catalyst. In one embodiment of the present disclosure, the LLDPE is made using a Ziegler-Natta catalyst. In one embodiment of the present disclosure, the LLDPE is made using a single-site catalyst. In embodiments of the present disclosure, the LLDPE is made using a metallocene catalyst, a phosphinimine catalyst, or a constrained geometry catalyst. In one embodiment of the present disclosure, the LLDPE is made using a Ziegler-Natta catalyst in a solution phase polymerization process. In one embodiment of the present disclosure, the LLDPE is made using a single-site catalyst in a solution phase polymerization process.

[0185] In one embodiment of the present disclosure, the LLDPE is an ethylene copolymer containing ethylene and 1-octene as polymerized monomers and has a viscosity of 0.910 to 0.935 g / cm 3 and a melt index I2 of 0.8 to 10 g / 10 min.

[0186] <Medium Density Polyethylene (MDPE)> As used herein, the terms "medium density polyethylene" and "MDPE" refer to a density of about 0.936 g / cm 3 ~Approx. 0.949g / cm 3 refers to a polyethylene homopolymer or copolymer having a density of

[0187] In one embodiment of the present disclosure, the MDPE is an ethylene copolymer. In one embodiment of the present disclosure, the MDPE is an ethylene copolymer comprising, as polymerizable monomers, ethylene and an alpha-olefin selected from the group consisting of 1-butene, 1-hexene, 1-octene, and mixtures thereof. In one embodiment of the present disclosure, the MDPE is an ethylene copolymer comprising ethylene and 1-butene as polymerizable monomers. In one embodiment of the present disclosure, the MDPE is an ethylene copolymer containing ethylene and 1-hexene as polymerizable monomers. In one embodiment of the present disclosure, the MDPE is an ethylene copolymer comprising ethylene and 1-octene as polymerizable monomers. In one embodiment of the present disclosure, the MDPE is an ethylene copolymer comprising ethylene and 1-octene as polymerized monomers.

[0188] In one embodiment, the MDPE is about 0.936 g / cm 3 ~Approx. 0.949g / cm 3 In an embodiment of the present disclosure, the MDPE has a density of about 0.936 g / cm 3 , or about 0.938 g / cm 3 , or about 0.940 g / cm 3 From a low density of about 0.949 g / cm 3 , or about 0.947 g / cm 3 , or about 0.945 g / cm 3 , or about 0.942 g / cm 3 In an embodiment of the present disclosure, the MDPE has a density ranging from about 0.936 g / cm 3 ~Approx. 0.948g / cm 3 , or about 0.936 to about 0.946 g / cm 3 , or about 0.938 g / cm 3 ~Approx. 0.948g / cm 3 , or about 0.938 to about 0.946 g / cm 3 , or about 0.940 g / cm 3 ~Approx. 0.949g / cm 3 , or about 0.940 g / cm 3 ~Approx. 0.948g / cm 3 , or about 0.940 to about 0.946 g / cm 3 , or about 0.936 to about 0.945 g / cm 3 , or about 0.938 to about 0.945 g / cm 3 , or about 0.940 to about 0.945 g / cm 3 It has a density of

[0189] In one embodiment of the disclosure, the MDPE has a molecular weight distribution (Mw / Mn) of less than or equal to 10.0. In further embodiments of the disclosure, the MDPE has a molecular weight distribution (Mw / Mn) of less than or equal to 9.0, less than or equal to 8.0, less than or equal to 7.0, or less than or equal to 6.0.

[0190] In one embodiment of the present disclosure, the MDPE has a molecular weight distribution (Mw / Mn) of about 1.6 to about 8.0.

[0191] In an embodiment of the present disclosure, the MDPE has a molecular weight distribution (Mw / Mn) ranging from a low molecular weight of about 1.6, or about 1.7, or about 2.0, or about 2.5, or about 3.0, or about 3.5, to a high molecular weight of about 4.5, or about 5.0, or about 5.25, or about 5.5, or about 6.0, or about 7.0, or about 8.0. In an embodiment of the present disclosure, the MDPE has a viscosity of from about 1.7 to about 5.5, or from about 1.7 to about 5.0, or from about 1.7 to about 4.5, or from about 1.7 to about 4.0, or from about 1.8 to about 3.5, or from about 2.0 to about 3.0, or from about 2.0 to about 10.0, or from about 2.0 to about 9.0, or from 2.0 to about 8.0, or from about 2.0 to about 7.0, or from about 2.0 to about 6.0, or from about 2.0 to about 5.0, or from about 2.0 to about 4.0, or from about 2.0 to about 3.5, or from about 2.5 to about 5.0. The molecular weight distribution (Mw / Mn) is about 10.0, or about 2.5 to about 9.0, or 2.5 to about 8.0, or about 2.5 to about 7.0, or about 2.5 to about 6.0, or about 2.5 to about 5.0, or about 2.5 to about 4.0, or about 2.5 to about 3.5; or about 3.0 to about 10.0, or about 3.0 to about 9.0, or about 3.0 to about 8.0, or about 3.0 to about 7.0, or about 3.0 to about 6.0, or about 3.0 to about 5.0, or about 3.0 to about 4.0.

[0192] In some embodiments, the MDPE can have a Z-average molecular weight distribution, Mz / Mw, ratio of 1.5 to 6.0, including all values ​​and subranges subsumed within this range. For example, in further embodiments, the MDPE can have a Z-average molecular weight distribution, Mz / Mw, from a lower limit of 1.5, or 1.75, or 2.0, or 2.5, or 2.75, or 3.0, or 3.5, to an upper limit of 2.0, or 2.5, or 3.0, or 3.5, or 4.0, or 4.5, or 5.0, or 5.5, or 6.0. In some embodiments, the MDPE has a Z-average molecular weight distribution, Mz / Mw, ratio of 1.5 to 5.5, or 1.5 to 5.0, or 1.5 to 4.0, or 1.5 to 3.5, or 1.5 to 3.0, or 1.5 to 2.5.

[0193] In embodiments of the present disclosure, the MDPE may be unimodal, bimodal, or multimodal in gel permeation chromatography (GPC) analysis. The term "unimodal" is defined herein to mean the presence of only one clear, significant peak or maximum in a molecular weight distribution curve generated according to the method of ASTM D6474-99. In contrast, use of the term "bimodal" is meant to convey the presence of a second peak or shoulder representing a higher or lower molecular weight component in addition to the first peak (i.e., the molecular weight distribution can be said to have two maxima in the molecular weight distribution curve). Alternatively, the term "bimodal" refers to the presence of two maxima in a molecular weight distribution curve generated according to the method of ASTM D6474-99. The term "multimodal" refers to the presence of two or more, typically more than two, maxima in a molecular weight distribution curve generated according to the method of ASTM D6474-99.

[0194] In one embodiment of the present disclosure, the MDPE has a melt index (I2) of about 0.1 g / 10 min to about 20 g / 10 min. In an embodiment of the present disclosure, the MDPE has a melt index (I2) ranging from about 0.75 g / 10 min to about 15 g / 10 min, or from about 0.85 g / 10 min to about 10 g / 10 min, or from about 0.9 g / 10 min to about 8 g / 10 min. In an embodiment of the present disclosure, the MDPE has a melt index (I2) ranging from a low melt index of about 0.20 g / 10 min, or about 0.25 g / 10 min, or about 0.5 g / 10 min, or about 0.75 g / 10 min, or about 1 g / 10 min, or about 2 g / 10 min, to a high melt index of about 3 g / 10 min, or about 4 g / 10 min, or about 5 g / 10 min, or about 10 g / 10 min.

[0195] In an embodiment of the present disclosure, the MDPE has a melt index (I2) of 0.1 to 10 g / 10 min, or 0.5 to 10.0 g / 10 min, or 0.5 to 5.0 g / 10 min, or 0.8 to 5.0 g / 10 min.

[0196] In an embodiment of the present disclosure, the MDPE has a melt index (I2) of from about 0.75 g / 10 min to about 6 g / 10 min, or from about 1 g / 10 min to about 8 g / 10 min, or from about 0.8 g / 10 min to about 6 g / 10 min, or from about 1 g / 10 min to about 4.5 g / 10 min, or from about 0.20 g / 10 min to about 5.0 g / 10 min, or from about 0.30 g / 10 min to about 5.0 g / 10 min, or from about 0.40 g / 10 min to about 5.0 g / 10 min, or from about 0.50 g / 10 min to about 5.0 g / 10 min, or from about 0.5 to 2.5 g / 10 min, or from about 0.5 to 2.0 g / 10 min.

[0197] In an embodiment of the present disclosure, the MDPE has a melt flow ratio I of 20 to 80. 21For example, in further embodiments, the MDPE can have a melt index ratio I / I2 of 20 to 75, or 20 to 70, or 20 to 65, or 20 to 60, or 20 to 55, or 20 to 50, or 25 to 75, or 25 to 70, or 25 to 65, or 25 to 60, or 25 to 55, or 25 to 50, or 30 to 80, or 30 to 75, or 30 to 70, or 30 to 65, or 30 to 60, or 30 to 55, or 30 to 50, or 35 to 80, or 35 to 75, or 35 to 70, or 35 to 65, or 35 to 60, or 35 to 55 g / 10 min. 21 / I2.

[0198] In other embodiments, the MDPE has a melt flow ratio I of less than 50, less than 47, less than 45, less than 42, less than 40, less than 35, or less than 30. 21 In further embodiments, the MDPE may have a melt index ratio I / I2 of 20 to 40, 20 to 37, 22 to 37, 22 to 35, 25 to 35, or 25 to 30. 21 / I2.

[0199] In an embodiment of the present disclosure, the MDPE has a melt flow ratio (I) of less than about 36, or less than about 35, or less than about 32, or less than about 30, or less than about 28, or less than about 26, or less than about 24, or less than about 22, or less than about 20. 21 In an embodiment of the present disclosure, the MDPE has a melt flow ratio (I / I2) of about 16 to about 36, or about 16 to about 35, or about 16 to about 32, or about 16 to about 30, or about 18 to about 35, or about 18 to about 32, or about 18 to about 30, or about 16 to about 27, or about 16 to about 25, or about 16 to about 22, or about 16 to about 20. 21 / I2).

[0200] In one embodiment of the present disclosure, the MDPE contains greater than or equal to about 50% by weight of CBDI as determined by TREF analysis. 50 or about 50% by weight or less of CBDI 50 It has.

[0201] In an embodiment of the present disclosure, the MDPE has a Composition Distribution Breadth Index (CDBI) of from about 25% to about 95% by weight, or from about 35% to about 90% by weight, or from about 40% to about 85% by weight, or from about 40% to about 80% by weight, as determined by Temperature Elution Fractionation (TREF). 50 It has.

[0202] In embodiments of the present disclosure, the MDPE can be produced using a gas phase polymerization process, a solution phase polymerization process, or a slurry phase polymerization process, or any combination thereof, using any type of reactor or reactor configuration known in the art (e.g., fluidized bed gas phase reactors, loop reactors, stirred tank reactors, batch reactors, etc.; and reactors can be connected in series or parallel, and any combination thereof).

[0203] In an embodiment of the present disclosure, the MDPE has a melt index (I2) of 0.1 to 10 g / 10 min, or 0.9 to 2.3 g / 10 min, and a melt index (I2) of about 0.936 to about 0.949 g / cm 3 It has a density of

[0204] In embodiments, the MDPE may be a homogeneously branched polyethylene. In embodiments, the MDPE may be a heterogeneously branched polyethylene.

[0205] In one embodiment of the present disclosure, the MDPE is made using a multi-site catalyst. In one embodiment of the present disclosure, the MDPE is made using a Ziegler-Natta catalyst. In one embodiment of the present disclosure, the MDPE is made using a single-site catalyst. In an embodiment of the present disclosure, the MDPE is made using a metallocene catalyst, a phosphinimine catalyst, or a constrained geometry catalyst. In one embodiment of the present disclosure, MDPE is made using a Ziegler-Natta catalyst in a solution phase polymerization process. In one embodiment of the present disclosure, the MDPE is made using a single-site catalyst in a solution phase polymerization process.

[0206] In one embodiment, the MDPE is an ethylene copolymer comprising ethylene and 1-octene as polymerized monomers and has a viscosity of 0.936 to 0.949 g / cm 3 and a melt index I2 of 0.8 to 10 g / 10 min.

[0207] <Other additives> The first, second, or third polyethylene, in embodiments of the present disclosure, may contain conventional additives selected from the group consisting of: primary antioxidants (such as hindered phenols, including vitamin E); secondary antioxidants (such as phosphites and phosphonites); ultraviolet absorbers and light stabilizers; processing aids (such as fluoroelastomers and / or polyethylene glycol-bound processing aids); slip agents; fillers, antiblocking agents, and reinforcing agents; or other additives.

[0208] Further details of other additives that may be added to the first, second, or third polyethylene in embodiments of the present disclosure are provided below.

[0209] In embodiments of the present disclosure, other additives may also be used in amounts of 100 to 5,000 ppm, or 100 to 3,000 ppm, or 200 to 3,000 ppm, or 200 to 2,000 ppm (based on the weight of the polymer).

[0210] <Primary antioxidant> In an embodiment of the present disclosure, the primary antioxidant is selected from alkylated monophenols such as, for example, 2,6-di-tert-butyl-4-methylphenol; 2-tert-butyl-4,6-dimethylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,6-di-tert-butyl-4-n-butylphenol; 2,6-di-tert-butyl-4-isobutylphenol; 2,6-dicyclopentyl-4-methylphenol; 2-(alpha-methylcyclohexyl)-4,6-dimethylphenol; 2,6-di-octadecyl-4-methylphenol; 2,4,6-tricyclohexylphenol; and 2,6-di-tert-butyl-4-methoxymethylphenol.

[0211] In an embodiment of the present disclosure, the primary antioxidant is selected from alkylated hydroquinones such as, for example: 2,6-di-tert-butyl-4-methoxyphenol; 2,5-di-tert-butylhydroquinone; 2,5-di-tert-amyl-hydroquinone; and 2,6-diphenyl-4-octadecyloxyphenol.

[0212] In an embodiment of the present disclosure, the primary antioxidant is selected from hydroxylated thiodiphenyl ethers, such as, for example: 2,2′-thio-bis-(6-tert-butyl-4-methylphenol); 2,2′-thio-bis-(4-octylphenol); 4,4′-thio-bis-(6-tert-butyl-3-methylphenol); and 4,4′-thio-bis-(6-tert-butyl-2-methylphenol).

[0213] In an embodiment of the present disclosure, the primary antioxidant is selected from alkylidene bisphenols, such as, for example: 2,2'-methylene-bis-(6-tert-butyl-4-methylphenol); 2,2'-methylene-bis-(6-tert-butyl-4-ethylphenol); 2,2'-methylene-bis-(4-methyl-6-(alpha-methylcyclohexyl)phenol); 2,2'-methylene-bis-(4-methyl-6-cyclohexylphenol); 2,2'-methylene-bis-(6-nonyl-4-methyl Phenol; 2,2'-methylene-bis-(6-nonyl-4-methylphenol); 2,2'-methylene-bis-(6-(alpha-methylbenzyl)-4-nonylphenol); 2,2'-methylene-bis-(6-(alpha,alpha-dimethylbenzyl)-4-nonyl-phenol); 2,2'-methylene-bis-(4,6-di-tert-butylphenol); 2,2'-ethylidene-bis-(6-tert-butyl-4-isobutylphenol); 4,4'-methylene-bis-(2,6-di-tert-butylphenol) phenol;4,4'-methylene-bis-(6-tert-butyl-2-methylphenol);1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenol)butane 2,6-di-(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol;1,1,3-tris-(5-tert-butyl-4-hydroxy-2-methylphenyl)butane;1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-dodecyl-mercaptobutane;Ethylene glycol Other phenols such as monoacrylate esters of bisphenols such as ricol-bis-(3,3,-bis-(3'-tert-butyl-4'-hydroxyphenyl)-butyrate)-di-(3-tert-butyl-4-hydroxy-5-methylphenyl)-dicyclopentadiene; di-(2-(3'-tert-butyl-2'hydroxy-5'methylbenzyl)-6-tert-butyl-4-methylphenyl) terephthalate; and ethylidenebis-2,4-di-t-butylphenol monoacrylate.

[0214] In embodiments of the present disclosure, the primary antioxidant may be used in an amount of 100 to 5,000 ppm, or 100 to 3,000 ppm, or 200 to 3,000 ppm, or 200 to 2,000 ppm (based on the weight of the polymer).

[0215] <Secondary antioxidant> In embodiments of the present disclosure, the secondary antioxidant is selected from phosphites and phosphonites, such as, for example, triphenyl phosphite; diphenyl alkyl phosphates; phenyl dialkyl phosphates; tris(nonylphenyl) phosphite; trilauryl phosphite; trioctadecyl phosphite; distearyl pentaerythritol diphosphite; tris(2,4-di-tert-butylphenyl) phosphite; diisodecyl pentaerythritol diphosphite; 2,4,6-tri-tert-butylphenyl-2-butyl-2-ethyl-1,3-propanediol phosphite; bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite tristearyl sorbitol triphosphite; and tetrakis(2,4-di-tert-butylphenyl) 4,4′-biphenylene diphosphonite.

[0216] In embodiments of the present disclosure, the secondary antioxidant is selected from hydroxylamines and amine oxides, such as, for example, N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine, N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydroxylamine, N-heptadecyl-N-octadecylhydroxylamine, and N,N-dialkylhydroxylamine derived from hydrogenated tallow amine. Similar amine oxides are also suitable.

[0217] In embodiments of the present disclosure, secondary antioxidants may also be used in amounts of 100 to 5,000 ppm, or 100 to 3,000 ppm, or 200 to 3,000 ppm, or 200 to 2,000 ppm (based on the weight of the polymer).

[0218] <UV absorbers and light stabilizers> In an embodiment of the present disclosure, the UV absorber or light stabilizer is selected from 2-(2'-hydroxyphenyl)-benzotriazoles, such as, for example: 5'-methyl-, 3', 5'-di-tert-butyl-, 5'-tert-butyl-, 5'(1,1,3,3-tetramethylbutyl)-, 5-chloro-3', 5'-di-tert-butyl-, 5-chloro-3'-tert-butyl-5'-methyl-3'-sec-butyl-5'-tert-butyl-, 4'-octoxy, 3', 5'-ditert-amyl-3', 5'-bis-(alpha, alpha-dimethylbenzyl)-derivatives.

[0219] In an embodiment of the present disclosure, the UV absorber or light stabilizer is selected from 2-hydroxy-benzophenones, such as, for example, 4-hydroxy-4-methoxy-, 4-octoxy-, 4-decyloxy-, 4-dodecyloxy-, 4-benzyloxy, 4,2',4'-trihydroxy-, and 2'-hydroxy-4,4'-dimethoxy derivatives.

[0220] In an embodiment of the present disclosure, the UV absorber or light stabilizer is selected from sterically hindered amines such as, for example: bis(2,2,6,6-tetramethylpiperidyl)-sebacate; bis-5(1,2,2,6,6-pentamethylpiperidyl)-sebacate; n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonic acid bis(1,2,2,6,6-pentamethylpiperidyl) ester; 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidine and succinic acid. Condensation products of N,N'-(2,2,6,6-tetramethylpiperidyl)-hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine; tris-(2,2,6,6-tetramethylpiperidyl)-nitrilotriacetate, tetrakis-(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarbonic acid; and 1,1'(1,2-ethanediyl)-bis-(3,3,5,5-tetramethylpiperazinone). These amines are typically referred to as HALS (Hindered Amines Light Stabilizing) and include butanetetracarboxylic acid 2,2,6,6-tetramethylpiperidinol ester. Such amines include hydroxylamines derived from hindered amines. For example, di(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate; 1-hydroxy-2,2,6,6-tetramethyl-4-benzoxypiperidine; 1-hydroxy-2,2,6,6-tetramethyl-4-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy)-piperidine; and N-(1-hydroxy-2,2,6,6-tetramethyl-piperidin-4-yl)-ε-caprolactam.

[0221] In an embodiment of the present disclosure, the slip agent is selected from oleamide, erucamide, stearamide, and behenamide.

[0222] <Fillers, anti-blocking agents, and reinforcing agents> In an embodiment of the present disclosure, the filler, anti-blocking agent, or reinforcing agent is selected from calcium carbonate, diatomaceous earth, natural and synthetic silica, silicates, glass fiber, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, and graphite.

[0223] <Other additives> In an embodiment of the present disclosure, the other additives are selected from plasticizers, epoxidized vegetable oils such as epoxidized soybean oil, lubricants, emulsifiers, pigments, optical brighteners, flame retardants, antistatic agents, antifogging agents, foaming agents, and thiosynergists such as dilauryl thiodipropionate or distearyl thiodipropionate.

[0224] The following examples are presented for the purpose of illustrating selected embodiments of the present disclosure, and it is understood that the presented examples do not limit the scope of the presented claims. [Example]

[0225] <Polymer characteristic evaluation and test methods> Prior to testing, each polymer specimen was conditioned at 23±2°C and 50±10% relative humidity for at least 24 hours, with subsequent testing being performed at 23±2°C and 50±10% relative humidity. As used herein, the term "ASTM conditions" refers to a laboratory maintained at 23±2°C and 50±10% relative humidity, and the specimens to be tested were conditioned in this laboratory for at least 24 hours prior to testing. ASTM refers to American Society for Testing and Materials.

[0226] <density> The density of the polymer was determined using ASTM D792-13 (November 1, 2013).

[0227] <Melt index> The melt index of the polymer was determined using ASTM D1238 (August 1, 2013). Melt index, I2, I6, I 10 , and I 21were measured at 190°C using weights of 2.16 kg, 6.48 kg, 10 kg, and 21.6 kg, respectively. As used herein, the term "stress index" or its acronym "S.Ex." is defined by the following relationship: S.Ex.=log(I6 / I2) / log(6480 / 2160) (where I6 and I2 are the melt flow ratios measured at 190°C using loads of 6.48 kg and 2.16 kg, respectively.) In this disclosure, melt index is expressed using the units g / 10 min, or g / 10 min, or dg / min, or dg / min, which are equivalent.

[0228] <Neutron activation (elemental analysis)> Neutron activation analysis (NAA) was used to determine catalytic metal residues in polymers as follows: Polymer samples were loaded into radioactive vials (made of ultra-high purity polyethylene, internal volume 7 mL), and the sample weight was recorded. Using a pneumatic transfer system, the samples were placed in a SLOWPOKE™ reactor (Atomic Energy of Canada Limited, Ottawa, Ontario, Canada) and irradiated for 30–600 s for short-half-life elements (e.g., Ti, V, Al, Mg, and Cl) or 3–5 h for long-half-life elements (e.g., Zr, Hf, Cr, Fe, and Ni). The average thermal neutron flux in the reactor was 5 × 10 11 / cm 2 / s. After irradiation, the samples were removed from the reactor and aged to allow the radioactivity to decay; short-half-life elements were aged for 300 seconds, and long-half-life elements were aged for several days. After aging, the gamma-ray spectra of the samples were recorded using a germanium semiconductor gamma-ray detector (Ortec model GEM55185, Advanced Measurement Technology Inc., Oak Ridge, TN, USA) and a multichannel analyzer (Ortec model DSPEC Pro). The amount of each element in the sample was calculated from the gamma-ray spectrum and recorded in parts per million (ppm) relative to the total weight of the polymer sample. The NAA system was calibrated using Specpure standards (1,000 ppm solutions of the desired elements (>99% purity)). 1 mL of the solution (target element) was pipetted onto a 15 mm x 800 mm rectangular paper filter and air-dried. The filter paper was then placed in a 1.4 mL polyethylene irradiation vial and analyzed with the NAA system. The standards are used to determine the sensitivity (counts / µg) of the NAA procedure.

[0229] <Gel Permeation Chromatography (GPC)> Polymer sample (polymer) solutions (1–3 mg / mL) were prepared by heating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating it on a wheel in an oven at 150 °C for 4 hours. To stabilize the polymer against oxidative degradation, an antioxidant (2,6-di-tert-butyl-4-methylphenol (BHT)) was added to the mixture. The BHT concentration was 250 ppm. The polymer solution was chromatographed in a PL220 high-temperature chromatography unit equipped with four Shodex columns (HT803, HT804, HT805, and HT806) using TCB as the mobile phase at a flow rate of 1.0 mL / min at 140 °C, with differential refractive index (DRI) as the concentration detector. To protect the GPC column from oxidative degradation, BHT was added to the mobile phase at a concentration of 250 ppm. The sample injection volume was 200 μL. The GPC column was calibrated with narrow-distribution polystyrene standards. Polystyrene molecular weights were converted to polyethylene molecular weights using the Mark-Houwink equation as described in ASTM Standard Test Method D6474-12 (December 2012). Raw GPC data were processed with CIRRUS® GPC software to obtain molar mass averages (M n , M w , M z ) and molar mass distribution (e.g., polydispersity M w / M n In the polyethylene art, the commonly used term equivalent to GPC is SEC, or size exclusion chromatography.

[0230] <gpc-ftir> Polyethylene composition (polymer) solutions (2–4 mg / mL) were prepared by heating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating it on a wheel in an oven at 150 °C for 4 hours. To stabilize the polymer against oxidative degradation, the antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT) was added to the mixture. The BHT concentration was 250 ppm. The sample solution was chromatographed on a WATERS GPC 150C chromatography unit equipped with four Shodex columns (HT803, HT804, HT805, and HT806) using TCB as the mobile phase at a flow rate of 1.0 mL / min at 140 °C. A FTIR spectrometer and a heated FTIR flow-through cell were connected to the chromatography unit via a heated transfer line as the detection system. To protect the SEC column from oxidative degradation, BHT was added to the mobile phase at a concentration of 250 ppm. The sample injection volume was 300 μL. The raw FTIR spectra were processed using OPUS FTIR software, and polymer concentration and methyl content were calculated in real time using the OPUS-associated Chemometric software (PLS technique). Polymer concentration and methyl content were then acquired and baseline corrected using CIRRUS GPC software. The SEC column was calibrated with narrow-dispersion polystyrene standards. Polystyrene molecular weights were converted to polyethylene molecular weights using the Mark-Houwink equation, as described in ASTM standard test method D6474. Comonomer content was calculated based on the polymer concentration and methyl content predicted by PLS technique, as described by Paul J. DesLauriers, Polymer 43, pp. 159-170 (2002); incorporated herein by reference.

[0231] <Short Chain Branching: GPC-FTIR> The short-chain branches per 1000 carbon atoms are measured for copolymer fractions with different molecular weights. When plotted on a semi-logarithmic graph, the sloping line (logarithmic horizontal x-axis from low to high molecular weight fractions and vertical y-axis representing the number of short-chain branches) represents the distribution of short-chain branches for the different molecular weight fractions as determined by Fourier transform infrared (FTIR) spectroscopy. The GPC-FTIR method measures the total methyl content, including the methyl groups located at the end of each polymer chain, i.e., the methyl end groups. Therefore, the raw GPC-FTIR data must be corrected by subtracting the contribution from the methyl end groups. More specifically, the raw GPC-FTIR data overestimate the amount of short-chain branches (SCB), and this overestimation increases as the molecular weight (M) decreases. In this disclosure, the raw GPC-FTIR data were corrected using the 2-methyl correction. At a given molecular weight (M), the total methyl end groups (N E ) is calculated using the following formula: N E = 28000 / M, calculated using N E (M dependent) was subtracted from the raw GPC-FTIR data to generate SCB / 1000C (2-methyl corrected) GPC-FTIR data.

[0232] <Unsaturated content> The amount of unsaturation, i.e., double bonds, in the polyethylene compositions was determined in accordance with ASTM D3124-98 (vinylidene unsaturation, published March 2011) and ASTM D6248-98 (vinyl and trans unsaturation, published July 2012). Ethylene interpolymer samples were a) first subjected to carbon disulfide extraction to remove additives that could interfere with the analysis; b) the samples (pellets, films, or granules) were pressed into plaques of uniform thickness (0.5 mm); and c) the plaques were analyzed by FTIR.

[0233] <Comonomer content: Fourier transform infrared (FTIR) spectroscopy> The amount of comonomer in the polyethylene compositions was determined by FTIR and reported as short-chain branching (SCB) content, measured as CH3# / 1000C (number of methyl branches per 1000 carbon atoms). This test was completed in accordance with ASTM D6645-01 (2001) using compression-molded polymer plaques and a Thermo-Nicolet 750 Magna-IR spectrophotometer. Polymer plaques were prepared in accordance with ASTM D4703-16 (April 2016) using a compression molding apparatus (Wabash-Genesis series press).

[0234] <Differential scanning calorimetry (DSC)> DSC testing was performed according to ASTM D3418. The analysis was performed by subjecting a polymer sample (5–10 mg prepared in an aluminum pan) and a reference material (an empty aluminum pan) to a constant rate of temperature change in a DSC cell. The actual temperatures of the sample and reference material were monitored by the instrument as the sample temperature increased or decreased linearly with time. If the sample undergoes a transition, reaction, or transformation, its rate of temperature change will differ from that of the reference material. The instrument (TA Instruments Q2000) was first calibrated with indium. After calibration, the polymer specimen was equilibrated at 0°C, the temperature was increased to 200°C at a heating rate of 10°C / min, and the melt was then isothermally held at 200°C for 5 minutes. The melt was then cooled to 0°C at a cooling rate of 10°C / min and held at 0°C for 5 minutes. The specimen was then heated to 200°C at a heating rate of 10°C / min. The temperature difference between the sample and the reference (DT = Treference - Tsample) was then plotted against the temperature of the sample to generate a differential thermogram, from which the melting peak temperature (°C), melting enthalpy (J / g), and crystallinity (%) were determined.

[0235] <Dynamic mechanical analysis (DMA)> Oscillatory shear measurements at small strain amplitudes were performed at 190 °C under a N2 atmosphere, with a 10% strain amplitude and five points per 100 μm, to obtain linear viscoelastic functions over a frequency range of 0.02 to 126 rad / s. Frequency sweep experiments were performed on a TA Instruments DHR3 stress-controlled rheometer using a cone-plate geometry with a 5° cone angle, a 137 μm truncation, and a 25 mm diameter. In these experiments, a sinusoidal strain wave was applied, and the stress response was analyzed in terms of linear viscoelastic functions. Zero shear rate viscosity (η) based on DMA frequency sweep results was predicted using the Ellis model (see R.B. Bird et al., "Dynamics of Polymer Liquids. Volume 1: Fluid Mechanics," Wiley-Interscience Publications, 1987, p. 228) or the Carreau-Yasuda model (see K. Yasuda's (1979) PhD Thesis, Cambridge, IT). Dynamic rheological data were analyzed using rheometer software (i.e., Rheometrics RHIOS V4.4 or Orchestrator Software) to determine the melt elastic modulus G' (G''=500) at a reference melt viscosity (G'') value of G''=500 Pa. When necessary, values ​​were obtained by interpolation between available data points using the Rheometrics software.

[0236] Shear thinning index SHI (0.5,50) was calculated as the ratio of the complex viscosity estimated at a shear stress of 0.5 kPa to that estimated at a shear stress of 50 kPa. (0.5,50) provides information about the shear thinning behavior of polymer melts. High values ​​indicate a strong dependence of viscosity on changes in deformation rate (shear or frequency).

[0237] <Capillary Rheology> Rheological data obtained from a Dynisco LCR7000 capillary rheometer was used to obtain viscosity profiles at different shear rates for different resins. In a capillary extrusion rheometer, the material is held in a temperature-controlled barrel and forced by a piston into a die of precise dimensions. The bore size, die size, and piston speed determine the apparent shear rate applied to the material, and the force and die size are used to calculate the apparent shear stress. Shear viscosity can be obtained from the capillary flow method using Poiseuille's law.

number

[0238] The shear rate, shear stress, and shear viscosity determined using the Poiseuille equation are usually referred to as apparent shear viscosity, apparent shear stress, and apparent shear rate. This is because they do not take into account the non-Newtonian properties of most fluids and the pressure drop across the die inlet and outlet pressures. The test temperature was set at 200°C. For this evaluation, the capillary length used was 30.48 mm, and the die diameter was 1.524 mm.

[0239] <Melt strength> Melt strength is measured at 190°C on a Rosand RH-7 capillary rheometer (barrel diameter = 15 mm) using a flat die with a 2 mm diameter and L / D ratio of 10:1. Pressure transducer: 10,000 psi (68.95 MPa). Piston speed: 5.33 mm / min. Conveying angle: 52°. Conveying incremental speed: 50-80 m / min. 2 or 65±15m / min 2 The polymer melt is extruded through a capillary die at a constant rate, and then the polymer strand is drawn at an increasing conveying rate until it ruptures. The maximum steady value of force in the plateau region of the force versus time curve is defined as the melt strength of the polymer.

[0240] <Vicat softening point (temperature)> The Vicat softening point of polymer samples was determined in accordance with ASTM D1525-07, published December 2009. This test determines the temperature at which a specified needle penetration occurs when the sample is subjected to the test conditions of ASTM D1525-07, i.e., heating rate B (120±10°C / hr and 938 gram load (10±0.2 N load)).

[0241] <CYTSAF / TREF(CTREF)> The "Composition Distribution Breadth Index" (hereinafter, CDBI) of polymer samples was measured using a CRYSTAF / TREF200+ unit equipped with an IR detector (hereinafter, CTREF). The acronym "TREF" stands for Temperature Rising Elution Fractionation. CTREF was provided by Polymer Characterization SA (Valencia Technology Park, Gustave Eiffel, 8, Paterna, E-46980 Valencia, Spain). The CTREF was operated in TREF mode, which allows the determination of the elution temperature, Co / Ho ratio (copolymer / homopolymer ratio), and CDBI (Composition Distribution Breadth Index), i.e., CDBI 50 and CDBI 25 The chemical composition of a polymer sample as a function of pH was calculated. A polymer sample (80–100 mg) was placed in a CTREF reaction vessel. 35 mL of 1,2,4-trichlorobenzene (TCB) was added to the reaction vessel, and the polymer was dissolved by heating the solution to 150 °C for 2 h. An aliquot (1.5 mL) of the solution was then loaded onto a CTREF column packed with stainless steel beads. The sample-loaded column was then stabilized at 110 °C for 45 min. The polymer was then crystallized from the solution in the column by lowering the temperature to 30 °C at a cooling rate of 0.09 °C / min. The column was then equilibrated at 30 °C for 30 min. The crystallized polymer was then eluted from the column while TCB was flowed through the column at 0.75 mL / min, and the column was slowly heated from 30 °C to 120 °C at a heating rate of 0.25 °C / min. Raw CTREF data were processed using Polymer ChAR software, an Excel spreadsheet, and in-house developed CTREF software. 50 is defined as the percentage of polymers whose composition is within 50% of the median central comonomer composition; 50 was calculated from the composition distribution curve and the normalized cumulative integral of the composition distribution curve, as described in U.S. Patent No. 5,376,439. Those skilled in the art will understand that a calibration curve is required to convert the CTREF elution temperature to comonomer content, i.e., the amount of comonomer in the ethylene / α-olefin polymer fraction eluting at a particular temperature. The construction of such a calibration curve is described in the prior art, for example, Wild et al., J. Polym. Sci., Part B, Polym. Phys., Vol. 20(3), pp. 441-455, which is incorporated herein by reference in its entirety. CDBI calculated in a similar manner 25 ;CDBI 25 is defined as the percentage of polymers whose composition is 25% of the median central comonomer composition. At the end of each sample run, the CTREF column was cleaned for 30 minutes by bringing the temperature of the CTREF column to 160°C and running TCB (0.5 mL / min) through the column for 30 minutes.

[0242] <Hexane extract> Hexane extractables were determined in accordance with Federal Regulations 21 CFR § 177.1520 Para (c) 3.1 and 3.2. The amount of hexane extractable material in a sample was determined gravimetrically.

[0243] <Film Optics> Film optical properties were measured as follows: Haze and clarity were measured according to ASTM D1003-13 (November 15, 2013).

[0244] <Film mechanical properties> Tensile tests in both the machine and transverse directions (MD and TD, respectively) were performed according to ASTM D882 (ASTM D882-10 and ASTM D882-12). The specimen width used for tensile property measurements was 1.0 inch. The initial extension rate was 1.0 inch / min to 5% strain, after which the rate was increased to 20.0 inch / min until break. The grip spacing was 2.0 inches. The mechanical properties measured were tensile stress at break (reported in MPa), strain at yield (%), yield stress (MPa), strain at break (%), and stress at break (MPa). Modulus (MPa) was measured using specimens with a width of 1.0 inch and a grip spacing of 2 inches, at a test speed of 1.0 inch / min.

[0245] <Film heat shrinkage rate (%)> The shrinkage of the film was measured using a 10 x 10 cm film specimen placed in an oven in air at 120°C for 5 minutes. The machine and transverse lengths of the heated film were compared with those of the original film, and the relative decrease is reported as the shrinkage. (%) Shrinkage rate = L initial -L final ) / L initial (In the formula, L initial and L final are the lengths before and after heat treatment).

[0246] <Film thickness> The film thickness of the stretched multilayer films was measured according to ASTM D6988-13.

[0247] <First Polyethylene> For use as the first polyethylene, an ethylene copolymer was made substantially according to the disclosure of co-pending Canadian Patent Application No. 3,102,574. The ethylene copolymer (used as the first polyethylene) was prepared in a multi-zone solution polymerization process configured with three polymerization zones in series with one another, each defined by a different polymerization reactor (see Figure 1). The first polymerization zone was defined by a first tubular reactor (Reactor 1), the second polymerization zone was defined by an optionally stirred tank reactor (Reactor 2), and the third polymerization zone was defined by a second tubular reactor (Reactor 3). Each reactor had an inlet through which the process flow entered the reactor and an outlet through which the process flow exited the reactor. For the tubular reactors, the inlet was located at the upstream end of the reactor and the outlet was located at the downstream end of the reactor. In this polymerization process, the tank reactor (Reactor 2) receiving the process flow from the first tubular reactor was a stirred tank reactor, optionally with an agitator present, but was operated without agitation and thus functioned as a type of plug flow reactor. Thus, in this disclosure, the tank reactor, optionally equipped with an agitator, is said to be operating in "plug flow mode" when the agitator is off.

[0248] The first tubular reactor (Reactor 1) was a 6-inch diameter, 36.6-meter long, 500-liter total volume pipe. The polymerization reaction was initiated by injecting a Ziegler-Natta polymerization catalyst into the reactor inlet (position A in Figure 1) along with the solvent (cyclohexane), hydrogen, ethylene, and 1-butene. (Note: The Ziegler-Natta polymerization catalyst components were combined immediately upstream of the first tubular reactor inlet, as described further below; not shown in Figure 1). Hydrogen was also supplied to a second location (position B in Figure 1) downstream from the first tubular reactor inlet and approximately 50% along the length of the first tubular reactor. In this solution phase polymerization process, as the process flow moved from the first tubular reactor into the tank reactor and then into the second tubular reactor, the polymerization reaction continued throughout the length of the first tubular reactor, continued in the tank reactor (Reactor 2), and then continued throughout the length of the second tubular reactor. The polymerization reaction temperature profile was monitored using eight temperature indicators located along the first tubular reactor.

[0249] Reactor 2 was a 3,640-liter tank (or "autoclave") reactor protected by a safety valve set at 19.1 MPa. The tank reactor was constructed of carbon steel and had a Monel-plated inlet nozzle. Four 11.4-cm-wide baffles were positioned 6.35 cm vertically from the wall at 90° angles to each other to prevent circulation within the vessel caused by the presence of the agitator. The agitator had five hubs, each with six impeller blades, evenly spaced across the height of the reactor. The tank reactor agitator was not used during this solution-phase polymerization process (it was present but not turned on), and therefore the tank reactor was operated in "plug flow mode." Temperature indicators located throughout the tank reactor were used to monitor the polymerization reaction temperature profile. The tank reactor was also traced with high-pressure steam.

[0250] Reactor 3 was a second tubular reactor with a 10 inch diameter pipe and was 53 meters long. Temperature indicators placed throughout the tank reactor were used to monitor the polymerization reaction temperature profile.

[0251] The polymerization in the solution polymerization process was terminated by adding a catalyst deactivator to the outlet stream leaving the outlet of the second tubular reactor (Reactor 3). The catalyst deactivator used was pelargonic acid.

[0252] A solution absorbent (activated aluminum) is used to remove traces of metal residues (vanadium and zirconium) from Ziegler-Natta catalysts.

[0253] A two-stage devolatilization process was employed to recover the ethylene copolymer from the process solvent: two vapor / liquid separators were used and the second bottoms stream (from the second V / L separator) was passed through a gear pump / pelletizer combination.

[0254] DHT-4V (hydrotalcite), supplied by Kyowa Chemical Industry Co., Ltd. (Tokyo, Japan), can be used as a passivator or acid scavenger in the solution process. A slurry of DHT-4V in the process solvent may be added before the first V / L separator.

[0255] The resin product is pelletized in two single screw extruders, followed by deactivation of the pellets in a nitrogen and steam supplied stripper.

[0256] Prior to pelletizing, the ethylene copolymer was stabilized by adding 1,000 ppm IRGANOX® 1010 (primary antioxidant) and 1,000 ppm IRGAFOS® 168 (secondary antioxidant), based on the weight of the ethylene copolymer composition. The antioxidants were dissolved in process solvent and added between the first and second V / L separators.

[0257] The Ziegler-Natta polymerization catalyst used to conduct the polymerization reaction was fed into the inlet of the first tubular reactor and consisted of three components: (i) vanadium precatalyst compound, VOCl3; (ii) titanium precatalyst component, titanium tetrachloride, TiCl4; and (iii) cocatalyst compound, triethylaluminum, (C2H5)3Al. The VOCl3 and TiCl4 compounds were first mixed (in cyclohexane) in an 80 / 20 weight ratio and then mixed with triethylaluminum at the inlet of the first tubular reactor (location A in Figure 1) just before injection into the first tubular reactor.

[0258] Details of the solution phase polymerizations carried out in a multi-zone reactor system are shown in Table 1. Details of the resulting ethylene copolymers are shown in Table 2.

[0259] [Table 1]

[0260] [Table 2]

[0261] <Second polyethylene> For use as the second polyethylene, a polyethylene homopolymer composition was made substantially according to the disclosure of U.S. Patent Application Publication Nos. 2013 / 0225743 or 2008 / 0118749, and according to the teachings of U.S. Provisional Application No. 63 / 023,270.

[0262] The polyethylene homopolymer compositions used in this example were as follows: Polyethylene homopolymer composition "C1": density 0.968 g / cm 3 , melt index (I2) 2.0 g / 10 min, molecular weight distribution 8.8; and polyethylene homopolymer composition "C2": density 0.967 g / cm 3 , melt index (I2) 1.2g / 10min, molecular weight distribution (M w / M n ) 8.5, commercially available from NOVA Chemicals as SURPASS® HPs167-AB.

[0263] Further details of the polyethylene homopolymer composition are provided in Table 3.

[0264] [Table 3]

[0265] <Addition of nucleating agent> The polyethylene homopolymer compositions ("C1" or "C2") were nucleated with 1,200 ppm (parts per million by weight) of HYPERFORM® HPN-20E, commercially available from Milliken. The nucleating agent is reported to be a combination of a) the calcium salt of HHPA and b) zinc stearate (2 / 1 weight ratio). To nucleate the polyethylene homopolymer compositions, an HPN-20E masterbatch was prepared, the masterbatch was let down to the appropriate level, and melt blended into the polyethylene homopolymer compositions.

[0266] Alternatively, an ethylene copolymer ("EC2") was nucleated with 4,000 ppm (parts per million by weight) of MICROTUFF AG609, commercially available from Specialty Minerals, Inc. To nucleate the ethylene copolymer, a masterbatch containing MICROTUFF AG609 was prepared, the masterbatch let down at the appropriate level, and melt compounded into the ethylene copolymer.

[0267] <Third Polyethylene> The linear low density polyethylene (LLDPE1) used as the third polyethylene in this example was SURPASS® FPs123-A, an ethylene copolymer containing ethylene and 1-octene, with a density of 0.923 g / cm 3 and a melt index (I2) of 1.3 g / 10 min and is commercially available from NOVAChemicals.

[0268] The medium-density polyethylene (MDPE1) used as the third polyethylene in this example is SURPASS FPs236-A, which is an ethylene copolymer containing ethylene and 1-octene, with a density of 0.936 g / cm 3 and a melt index (I2) of 2.9 g / 10 minutes, and is commercially available from NOVA Chemicals.

[0269] Another medium-density polyethylene (MDPE2) used as the third polyethylene in this example is SURPASS RMs341-U, which is an ethylene copolymer containing ethylene and 1-octene, with a density of 0.941 g / cm 3 and a melt index (I2) of 3.5 g / 10 minutes, and is commercially available from NOVA Chemicals.

[0270] <A. Preparation of Unstretched Film (or "Base Structure")> The multilayer (three-layer) sheet is co-extruded through a 17.2-inch slot or flat die with a flexible lip (adjustable gap) using a combination of a biaxial screw extruder and a uniaxial screw extruder. The molten streams are combined near the entrance of the die. The multilayer web extruded from the die is fixed to a casting roll or a cooling roll using an air knife and an edge pinner, and is rapidly cooled on the cooling roll. The primary cooling roll temperature was set at 76 °C. For convenience, this unstretched multilayer sheet may be referred to herein as the "base structure". The weight of the polymer used in each of the three layers is indicated in the form of A / B / C. For example, a base structure having two outer layers (or skin layers) each containing 15% by weight of the total polymer used in the film structure and a core layer containing 70% by weight of the total polymer used in the film structure is described as a 15 / 70 / 15 structure.

[0271] Several three-layer base film structures were prepared using various polyethylene materials, with structures ranging from 10 / 80 / 10 to 16 / 68 / 16, as described in Table 4. For layers containing a blend of two polyethylene materials (e.g., a core layer containing an ethylene copolymer and a nucleated ethylene homopolymer composition), the layer was cast as a polymer blend by blending pellets immediately prior to extrusion using an in-line gravimetric blending system.

[0272] [Table 4]

[0273] Biaxially oriented polyethylene (BOPE) films were prepared from each of these base multilayer film structures (Base Film Structure Nos. 1-15) using the procedure described in Part B below.

[0274] Part B. Preparation of BOPE Films - Sequential Stretching BOPE film structures were made using a sequential stretching process on a tenter-frame biaxial stretching line. First, the machine direction stretch / orientation was performed. The "oriented" sheet was then stretched in the transverse direction.

[0275] Machine direction orientation (MDO) was accomplished using either a single-stage or multi-stage short-gap stretching process at temperatures up to 245°F and stretch ratios up to about 6.5:1. Transverse direction orientation (TDO) was accomplished in multiple zones: a preheat zone, a stretch zone, an annealing zone, and finally a cooling zone. The TDO stretch zone temperatures were up to 280°F and the stretch ratios up to about 5.5:1.

[0276] MDO is achieved by preheating the base film and stretching the sheet between a set or stack of heated rollers rotating at different speeds. The difference in roll speeds determines the stretch ratio. Stretching can be done with a single set of stretch rolls or on a series of stretch rolls. Stretching is generally done at a temperature below the crystalline melting temperature (Tm) of the film. The MDO film is then fed into a tenter frame oven using clips on chains attached to rails and preheated. As the rails move apart, the edges of the film are pulled, stretching the film, resulting in transverse stretching. The film's width is set by the distance between the rails and can be adjusted to achieve the desired stretch ratio. TDO is generally performed at a temperature equivalent to or slightly higher than MDO. The film can be annealed or relaxed as it exits the TDO unit. After TDO, the film can be cooled and wound. Typical process conditions used in the tenter frame process are summarized in Table 5.

[0277] [Table 5]

[0278] All base film structures in Table 4 (Base Film Structure Nos. 1-15) were successfully converted to BOPE film structures (BOPE Film Structure Nos. 1-15). Selected properties of these biaxially oriented multilayer film structures are shown in Table 6.

[0279] [Table 6]

[0280] As can be seen from the data presented in Table 6, when biaxially oriented film structures have a core layer comprising an ethylene copolymer and a nucleated polyethylene homopolymer composition, the film structures have very good haze and clarity: haze is less than 15% and clarity is greater than 80%. Remarkably, good haze and clarity were maintained even when the core layer contained very low amounts of nucleated polyethylene homopolymer composition (e.g., when the core layer contained a blend of at least 95% by weight ethylene copolymer and 5% by weight or less of the nucleated polyethylene homopolymer composition (see BOPE Film Nos. 6, 7, 8, 9, 14, and 15)). Good haze and clarity values ​​were maintained even in film structures having different materials in the first and second adjacent layers (e.g., skin layers) as long as the core layer contained an ethylene copolymer and a nucleated polyethylene homopolymer composition. For comparison, when the core layer was composed solely of a non-nucleated ethylene copolymer (Film Nos. 1, 2, and 11), or when the core layer was composed of a blend of an ethylene copolymer and a non-nucleated polyethylene homopolymer composition (Film No. 10), or when the core layer was composed of a blend of an ethylene copolymer and a nucleated ethylene copolymer (Film No. 13), one or both of the haze and clarity of the BOPE film structures were adversely affected.

[0281] Non-limiting embodiments of the present disclosure include the following:

[0282] Embodiment A. A biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 a second polyethylene which is a polyethylene homopolymer composition having a density of Including, the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise at least 50 wt. % of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; Biaxially oriented polyethylene film structure.

[0283] Embodiment B. The polyethylene homopolymer composition has a viscosity of 0.952 to 0.975 g / cm 3 The biaxially oriented polyethylene film structure of embodiment A, having a density of

[0284] Embodiment C. The biaxially oriented polyethylene film structure of embodiment A or B, wherein the polyethylene homopolymer composition has a melt index of 0.5 to 5.0 g / 10 min.

[0285] Embodiment D. The polyethylene homopolymer composition comprises: i) 0.950-0.975g / cm 3 5 to 70 wt. % of a first ethylene homopolymer having a density of ii) 0.950-0.975 g / cm 3 95 to 30% by weight of a second ethylene homopolymer having a density of Including, The biaxially oriented polyethylene film structure of embodiment A, B, or C, wherein the ratio of the melt index I2 of the second ethylene homopolymer to the melt index I2 of the first ethylene homopolymer is at least 10.

[0286] Embodiment E. The first polyethylene has a viscosity of 0.941 to 0.962 g / cm 3 The biaxially oriented polyethylene film structure of embodiment A, B, C, or D, having a density of

[0287] Embodiment F. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, or E, wherein the first polyethylene has a melt index of 0.5 to 5.0 g / 10 min.

[0288] Embodiment G. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, or F, wherein the first polyethylene has a molecular weight distribution of 3.0 to 20.0.

[0289] Embodiment H. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, or F, wherein the first polyethylene has a molecular weight distribution of 8.5 to 20.0.

[0290] Embodiment I. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, or H, wherein the first polyethylene has a Z-average molecular weight, Mz, of at least 500,000 g / mole.

[0291] Embodiment J. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, or I, wherein the polyethylene homopolymer composition comprises from 100 to 3,000 ppm (based on the weight of the polyethylene homopolymer composition) of a nucleating agent or mixture of nucleating agents.

[0292] Embodiment K. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, I, or J, wherein the nucleating agent or mixture of nucleating agents comprises a salt of a dicarboxylic acid.

[0293] Embodiment L. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, I, J, or K, wherein the third polyethylene is selected from the group consisting of linear low density polyethylene (LLDPE), and medium density polyethylene (MDPE).

[0294] Embodiment M. The core layer comprises: i) 70 to 99.5 wt% of a first polyethylene; ii) 0.5 to 30 wt. % of a second polyethylene; The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, I, J, K, or L, comprising:

[0295] Embodiment N. The core layer comprises: i) 90 to 99.5 wt% of a first polyethylene; ii) 0.5 to 10 wt. % of a second polyethylene; The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, I, J, K, or L, comprising:

[0296] Embodiment O. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, or N having a haze value of less than 15%.

[0297] Embodiment P. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, N, or O having a clarity value of greater than 80%.

[0298] Embodiment Q. The biaxially oriented polyethylene film structure of embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, or P, wherein the first adjacent layer and the second adjacent layer are skin layers.

[0299] Embodiment R. A biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent to the second side of the core layer; Including, The core layer is i) 50 to 99.5 wt % of a first polyethylene, the first polyethylene being 0.940 g / cm 3 a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a density of at least 0.950 g / cm 3 a second polyethylene which is a high density polyethylene having a density of Including, the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise at least 50 wt. % of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; The biaxially oriented polyethylene film structure has a haze value of less than 15%. Biaxially oriented polyethylene film structure.

[0300] Embodiment S. The biaxially oriented polyethylene film structure of embodiment R, wherein the third polyethylene is selected from the group consisting of linear low density polyethylene (LLDPE) and medium density polyethylene (MDPE).

[0301] Embodiment T. The core layer comprises: i) 70 to 99.5 wt% of a first polyethylene; ii) 0.5 to 30 wt. % of a second polyethylene; The biaxially oriented polyethylene film structure of embodiment R or S, comprising:

[0302] Embodiment U. The core layer comprises: i) 90 to 99.5 wt% of a first polyethylene; ii) 0.5 to 10 wt. % of a second polyethylene; The biaxially oriented polyethylene film structure of embodiment R or S, comprising:

[0303] Embodiment V. The biaxially oriented polyethylene film structure of embodiment R, S, T, or U having a clarity value greater than 80%.

[0304] Embodiment W. The biaxially oriented polyethylene film structure of embodiment R, S, T, U, or V, wherein the first adjacent layer and the second adjacent layer are skin layers. [Industrial Applicability]

[0305] Provided is a biaxially oriented polyethylene (BOPE) film structure comprising at least three layers. The BOPE film structure has good optical properties and excellent recyclability, making it suitable for a variety of packaging applications.

Claims

1. 1. A biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt. % of a first polyethylene, the first polyethylene having a viscosity of 0.940 g / cm ３ a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a viscosity of at least 0.950 g / cm ３ a second polyethylene which is a polyethylene homopolymer composition having a density of Including, the polyethylene homopolymer composition comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise at least 50 wt. % of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; Biaxially oriented polyethylene film structure.

2. The polyethylene homopolymer composition has a viscosity of 0.952 to 0.975 g / cm ３ 10. The biaxially oriented polyethylene film structure of claim 1 having a density of

3. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the polyethylene homopolymer composition has a melt index of 0.5 to 5.0 g / 10 min.

4. The polyethylene homopolymer composition comprises: i) 0.950-0.975g / cm ３ 5 to 70 wt. % of a first ethylene homopolymer having a density of ii) 0.950-0.975g / cm ３ 95 to 30% by weight of a second ethylene homopolymer having a density of Including, the melt index I of the first ethylene homopolymer ２ the melt index I of the second ethylene homopolymer relative to ２ is at least 10; 10. The biaxially oriented polyethylene film structure of claim 1.

5. The first polyethylene has a viscosity of 0.941 to 0.962 g / cm ３ 10. The biaxially oriented polyethylene film structure of claim 1 having a density of

6. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the first polyethylene has a melt index of 0.5 to 5.0 g / 10 min.

7. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the first polyethylene has a molecular weight distribution of 3.0 to 20.

0.

8. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the first polyethylene has a molecular weight distribution of 8.5 to 20.

0.

9. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the first polyethylene has a Z average molecular weight, Mz, of at least 500,000 g / mol.

10. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the polyethylene homopolymer composition comprises 100 to 3,000 ppm (based on the weight of the polyethylene homopolymer composition) of a nucleating agent or mixture of nucleating agents.

11. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the nucleating agent or mixture of nucleating agents comprises a salt of a dicarboxylic acid.

12. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the third polyethylene is selected from the group consisting of linear low density polyethylene (LLDPE) and medium density polyethylene (MDPE).

13. The core layer, i) 70 to 99.5 wt. % of a first polyethylene; ii) 0.5 to 30 wt. % of a second polyethylene; 10. The biaxially oriented polyethylene film structure of claim 1, comprising:

14. The core layer, i) 90 to 99.5 wt. % of a first polyethylene; ii) 0.5 to 10 wt. % of a second polyethylene; 10. The biaxially oriented polyethylene film structure of claim 1, comprising:

15. 10. The biaxially oriented polyethylene film structure of claim 1 having a haze value of less than 15%.

16. 10. The biaxially oriented polyethylene film structure of claim 1 having a clarity value greater than 80%.

17. 10. The biaxially oriented polyethylene film structure of claim 1, wherein the first adjacent layer and the second adjacent layer are skin layers.

18. 1. A biaxially oriented polyethylene film structure comprising: A core layer; a first adjacent layer adjacent a first side of the core layer; a second adjacent layer adjacent the second side of the core layer; and Including, The core layer is i) 50 to 99.5 wt. % of a first polyethylene, the first polyethylene having a viscosity of 0.940 g / cm ３ a first polyethylene which is an ethylene copolymer having a density greater than ii) 0.5 to 50 wt. % of a second polyethylene, the second polyethylene having a viscosity of at least 0.950 g / cm ３ a second polyethylene which is a high density polyethylene having a density of Including, the high density polyethylene comprises a nucleating agent or a mixture of nucleating agents; the first adjacent layer and the second adjacent layer each comprise at least 50 wt. % of a third polyethylene, the third polyethylene having a density lower than the density of the first polyethylene; The biaxially oriented polyethylene film structure has a haze value of less than 15%. Biaxially oriented polyethylene film structure.

19. 20. The biaxially oriented polyethylene film structure of claim 18, wherein the third polyethylene is selected from the group consisting of linear low density polyethylene (LLDPE) and medium density polyethylene (MDPE).

20. The core layer, i) 70 to 99.5 wt. % of a first polyethylene; ii) 0.5 to 30 wt. % of a second polyethylene; 20. The biaxially oriented polyethylene film structure of claim 18, comprising:

21. The core layer, i) 90 to 99.5 wt. % of a first polyethylene; ii) 0.5 to 10 wt. % of a second polyethylene; 20. The biaxially oriented polyethylene film structure of claim 18, comprising:

22. 20. The biaxially oriented polyethylene film structure of claim 18 having a clarity value of greater than 80%.

23. 20. The biaxially oriented polyethylene film structure of claim 18, wherein the first adjacent layer and the second adjacent layer are skin layers.

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