Silobags including polyethylene

Abstract

Provided are multilayer films. The multilayer films according to embodiments disclosed herein are suitable for making silobags and include one or more core layer with a low amount of a polyethylene elastomer have a Brookfield Viscosity of less than 12.0 Pa.s. The multilayer films can have a desirable balance of properties such as puncture and tear properties.

Description

SILOBAGS INCLUDING POLYETHYLENETECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to multilayer films suitable for making silobags, and processes for making the same.INTRODUCTION

[0002] Silobags are an essential component in modern agricultural practices, offering a convenient and efficient method for storing and preserving grains, forage, and other agricultural products. These large, flexible storage solutions are designed to protect the contents from environmental factors such as moisture, pests, and UV exposure. By providing a controlled atmosphere, silobags can significantly prolong the shelf life of stored materials, ensuring that farmers can maintain the quality and nutritional value of their produce until it is ready to be used or sold.

[0003] The performance of silobags in the industry faces several challenges. One of the primary issues is the durability and strength of the materials used in their construction. Silobags must withstand harsh weather conditions, mechanical stress during filling and unloading, and potential damage from wildlife. Additionally, there is a need to balance the cost-effectiveness of production with the ability to provide adequate protection and longevity. Innovations in material science and manufacturing processes are crucial to address these concerns and enhance the overall performance of silobags, ensuring they remain a reliable and sustainable solution for agricultural storage. For instance, silobag applications made from blown multilayer films often require high MD tear propagation resistance for unloading, high puncture resistance against ground imperfections, high dart drop resistance to withstand heavy rains and hail, and high creep resistance to maintain shape. In addition to these challenges, the industry faces the challenge of downgauging and using less materials to perform similarly. Accordingly, new multilayer film formulations are necessary to meet silobag application requirements and reduce the use of materials.SUMMARY

[0004] Embodiments of the present disclosure meet one or more of the foregoing needs by providing a multilayer film that can achieve a balance of silobag properties.

[0005] In a first aspect, a multilayer film is disclosed. The multilayer film comprises a first outer layer, a second outer layer, and one or more core layers. The one or more core layers is positioned between the first outer layer and the second outer layer. The one or more core layers comprises at least 95 wt.% ethylene-based polymers, at least 65 wt.% linear low density polyethylene, less than 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers. A first core layer comprises a combination of a low density polyethylene, a linear low density polyethylene, and a polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s.

[0006] In a second aspect, a process for making a multilayer film is disclosed. The process comprises: extruding a first outer layer, a second outer layer, and one or more core layers to form a multilayer film, wherein the one or more core layers is positioned between the first outer layer and the second outer layer; the one or more core layers comprises at least 95 wt.% ethylene-based polymers, at least 65 wt.% linear low density polyethylene, less than 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers, wherein a first core layer comprises a combination of a low density polyethylene, a linear low density polyethylene, and a polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s.

[0007] These and other embodiments are described in more detail in the Detailed Description.DETAILED DESCRIPTION

[0008] Aspects of the disclosed multilayer films are described in more detail below. The multilayer films are suitable for making silobags and can have a wide variety of applications, including, for example, as coverings or bags or the like.

[0009] As used herein, the term “polymer” means a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer), and the term copolymer or interpolymer. Trace amounts of impurities (for example, catalyst residues) may be incorporated into and / or within the polymer. A polymermay be a single polymer, a polymer blend, or a polymer mixture, including mixtures of polymers that are formed in situ during polymerization.

[0010] As used herein, the term “copolymer” means a polymer formed by the polymerization reaction of at least two structurally different monomers. The term “copolymer” is inclusive of terpolymers.

[0011] As used herein, the terms “polyethylene” or “ethylene-based polymer” shall mean polymers comprising a majority amount (>50 mol %) of units which have been derived from ethylene monomer. This includes polyethylene homopolymers and copolymers (meaning units derived from two or more comonomers). The terms “ethylene-based polymer” and “polyethylene” may be used interchangeably. Generally, polyethylene may be produced in gas-phase, fluidized bed reactors, liquid phase slurry process reactors, or liquid phase solution process reactors, using a heterogeneous catalyst system, such as Ziegler-Natta catalyst, a homogeneous catalyst system, comprising Group 4 transition metals and ligand structures such as metallocene, non -metallocene metal-centered, heteroaryl, heterovalent aryloxyether, phosphinimine, and others. Combinations of heterogeneous and / or homogeneous catalysts also may be used in either single reactor or dual reactor configurations.

[0012] The term “low density polyethylene” or “LDPE” as used herein refers to as “high pressure ethylene polymer” or “highly branched polyethylene” and is defined to mean that the polymer is partly or entirely homo-polymerized or copolymerized in autoclave or tubular reactors at pressures above 14,500 psi (100 MPa) with the use of free-radical initiators, such as peroxides (see for example US 4,599,392, which is hereby incorporated by reference). The LDPE, as used herein, have a density in the range of 0.910 to 0.930 g / cm3.

[0013] The term “linear low density polyethylene” or “LLDPE”, includes resin made using the traditional Ziegler-Natta catalyst systems and chromium-based catalyst systems as well as single-site catalysts, including, but not limited to, substituted mono- or bis-cyclopentadienyl catalysts (typically referred to as metallocene), constrained geometry catalysts, phosphinimine catalysts & polyvalent aryloxyether catalysts (typically referred to as bisphenyl phenoxy), and includes linear, substantially linear or heterogeneous polyethylene copolymers or homopolymers. LLDPEs contain less long chain branching than LDPEs and includes the substantially linear ethylene polymers which are further defined in U.S. Patent 5,272,236, U.S. Patent 5,278,272, U.S. Patent 5,582,923 and US Patent 5,733,155; the homogeneouslybranched linear ethylene polymer compositions such as those in U.S. Patent No. 3,645,992; the heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698; and / or blends thereof (such as those disclosed in US 3,914,342 or US 5,854,045). The LLDPEs can be made via gas-phase, solution-phase or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art. The LLDPE, as used herein, have a density in the range of 0.910 to 0.940 g / cm3.

[0014] The term “polyethylene elastomer” shall mean an ethylene / a-olefin copolymer that (i) comprise units derived from ethylene and units derived from at least one C3-C10 a-olefin comonomer, or at least one C4-C8 a-olefin comonomer, or at least one C6-C8 a-olefin comonomer; and (ii) has a density from 0.865 g / cm , or 0.870 g / cm5, or 0.880 g / cm5, or 0.890 g / cm5to 0.900 g / cm5, or 0.902 g / cm5, or 0.904 g / cm5, or 0.909 g / cm5, or 0.910 g / cm5. Alpha-olefin comonomers include C3-C20 alpha-olefins, especially propene, isobutylene, 1 -butene, 1- hexene, 4-methyl-l -pentene, 1 -heptene, 1 -octene, 1 -nonene, and 1 -decene, 1-butene, 1 -hexene, 4-methyl-l -pentene and 1 -octene. This includes substantially linear, or linear, ethylene / a-olefin copolymers containing homogeneous short-chain branching distribution and ethylene / a-olefin multi-block copolymers. Nonlimiting examples of ethylenebased elastomers include commercially available elastomers such as ENGAGE™ Polyolefin Elastomers, and INFUSE™ Olefin Block Copolymers (available from The Dow Chemical Company), EXACT™ plastomers (available from ExxonMobil Chemical), Tafmer (available from Mitsui), Nexlene™ (available from SK Chemicals Co.), and Lucene™ (available LG Chem Ltd.).

[0015] The term “composition,” as used herein, refers to a mixture of materials that comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0016] The terms “comprising,” “including,” “having,” and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether the same is specifically disclosed. To avoid any doubt, all compositions claimed through use of the term “comprising” may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, “consisting essentially of’ excludes from the scope of any succeeding recitation any other component, stepor procedure, excepting those that are not essential to operability. The term “consisting of’ excludes any component, step or procedure not specifically delineated or listed.

[0017] Disclosed herein are multilayer films. The multilayer film comprises a first outer layer, a second outer layer, and one or more core layers, the one or more core layers positioned between the first outer layer and the second outer layer. The number of film layers of the multilayer film is not particularly limited, other than that the film has at least three layers, including a first outer layer, a first core layer, and a second outer layer. The position of the first core layer (e.g., when there are multiple core layers) is not particularly limited other than that it must be positioned between the first and second outer layers. In some embodiments, the multilayer film is a three layer film with a first outer layer, a second outer layer, and a first core layer. The multilayer film can comprise 4, 5, 6, 7, 8, 9, 10, 11 or more layers. In one embodiment, the multilayer film comprises five layers, including a first outer layer, a first core layer, a second core layer, a third core layer, and a second outer layer (A / B / C / D / E, where A and E are outer layers). The film can have different thicknesses. In some embodiments, the film has a thickness 10 to 500 microns, or 20 to 350 microns, or 50 to 300 microns, or 180 to 260 microns. When the film is a blown film suitable as a silobag, the film can be downgauged and retain a balance of properties as disclosed herein. In some embodiments, the film is a five-layer film having a layer ratio of 20 / 20 / 20 / 20 / 20 with equivalently distributed layers or is a five layer film having a layer ratio of 15 / 20 / 30 / 20 / 15, or ratios in between these embodiments. In some embodiments, each layer of the film is between 15 to 30% of the total thickness of the film. In some embodiments, the first outer layer is between 15 to 30% of the total thickness of the film. In some embodiments, the one or more core layers is between 40 to 70% of the total thickness of the film.

[0018] In some embodiments, the multilayer film comprises at least 95 wt.% ethylenebased polymers, or at least 97 wt.% ethylene-based polymers, or at least 99 wt.% ethylenebased polymers, based on the total weight of the film. In some embodiments, the multilayer film is void of polymers other than ethylene-based polymers. A film made of solely of or nearly all ethylene-based polymers may be more easily recycled.

[0019] In some embodiments, the multilayer film comprises at least 60 wt.% LLDPE, or at least 65 wt.% LLDPE, or at least 70 wt.% LLDPE, or from 60 to 80 wt.% LLDPE, based on the total weight of the film. In some embodiments, the multilayer film comprises less than 35 wt.% LDPE, less than 30 wt.% LDPE, less than 25 wt.% or less than 20 wt.% LDPE, based onthe total weight of the multilayer film. In some embodiments, the multilayer film comprises at least 15 wt.% LDPE, at least 20 wt.% LDPE, or at least 25 wt.% LDPE, or at least 30 wt.% LDPE, or from 15 to 40 wt.% LDPE, based on the total weight of the film. In some embodiments, the multilayer film comprises less than 3 wt.% polyethylene elastomer, less than 2 wt.% polyethylene elastomer, or less than 1 wt.% polyethylene elastomer, based on the total weight of the film. In some embodiments, the multilayer film comprises at least 0.1 wt.%, at least 0.5 wt.%, or at least 1 wt.% or at least 3 wt.% polyethylene elastomer, based on the total weight of the film. For example, in some embodiments, the multilayer film comprises from 65 to 80 wt.% linear low density polyethylene, 20 to 30 wt.% low density polyethylene, and less than 3 wt.% polyethylene elastomer, based on the total weight of the film.

[0020] Core Layer( s)

[0021] The multilayer film comprises one or more core layers. The one or more core layers are positioned between the first outer layer and the second outer layer. The one or more core layers comprises at least 95 wt.% ethylene-based polymers, at least 65 wt.% linear low density polyethylene, less than 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers. There is at least one core layer deemed “a first core layer” herein. Other specific core layers may be deemed “a second core layer” or a “third core layer.” The core layer(s) in the film is deemed “one or more core layers.” Where there is more than one core layer, the more than one core layers can be arranged in any order between the second outer layer and the first outer layer. In a three layer embodiments, the multilayer film has a first outer layer, a first core layer, and a second outer layer as the three layers. In some embodiments, the one or more core layers comprises at least 40% of the total thickness of the film. In some embodiments, the one or more core layers comprises from 40 to 70% of the total thickness of the film, or from 45 to 65% of the total thickness of the film.

[0022] The one or more core layers comprises at least 95 wt.% ethylene-based polymers. In some embodiments, the one or more core layer comprises at least 96, 97, 98, or 99 wt.% ethylene-based polymers, based on the total weight of the one or more core layers. The one or more core layers can be void of polymers other than ethylene-based polymers. The one or more core layers comprises at least 65 wt.% linear low density polyethylene. In some embodiments, the one or more core layers comprises at least 66, 67, 68, 69, or 70 wt.% linear low density polyethylene, based on the total weight of the one or more core layers, or comprisesfrom 65 to 80 wt.% or 65 to 75 wt.% of linear low density polyethylene, based on the total weight of the one or more core layers. The one or more core layers comprises less than 30 wt.% low density polyethylene. In some embodiments, the one or more core layers comprises less than 29, 28, 27, 26, or 25 wt.% of low density polyethylene, based on the total weight of the low density polyethylene, or from 15 to 30 wt.%, or 20 to 30 wt.%, or 22 to 27 wt.% low density polyethylene, based on the total weight of the one or more core layers. The one or more core layers comprises less than 5 wt.% polyethylene elastomer. In some embodiments, the one or more core layers comprises less than 4, 3, or 2, wt.% polyethylene elastomer, or from 0.5 to 5 wt.%, or 1 to 5 wt.% or from 1 to 4 wt.% polyethylene elastomer, based on the total weight of the one or more core layers. In some embodiments, for example, the one or more core layers comprises from 65 to 80 wt.% linear low density polyethylene, 20 to 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers.

[0023] The first core layer comprises a combination of a low density polyethylene, a linear low density polyethylene, and a polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s. These are specific ethylene-based polymers of the first core layer and are ethylene-based polymers contributing to weight percentages in the one or more core layers or film. The one or more core layers may include additional types of LLDPE, LDPE, or polyethylene elastomer (e.g., different densities or melt indices that fit within the definitions above) as well to arrive at the weight percentages recited herein of the one or more core layers, as is well known to those skilled in the art. In some embodiments, where the first core layer is the only core layer, the first core layer comprises at least 95 wt.% ethylene-based polymers, at least 65 wt.% linear low density polyethylene, less than 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer.

[0024] In some embodiments, the low density polyethylene of the first core layer has a density between 0.910 to 0.930 g / cc and a melt index (E) of 0.1 to 7.0 g / 10 min. In some embodiments, the low density polyethylene of the first core layer has a density of a lower limit of 0.910, 0.912, 0.914, 0.916, 0.918, or 0.920 g / cc and an upper limit of 0.928, 0.926, 0.924, or 0.922 g / cc. In some embodiments, the low density polyethylene of the first core layer has a melt index (I2) of from 0.1 to 6.0 g / 10 min, from 0.1 to 6.0 g / 10 min, 0.1 to 5.0 g / 10 min, 0.1 to 4.0 g / 10 min, 0.1 to 3.0 g / 10 min, 0.1 to 2.0 g / 10 min, or 0.2 to 1.0 g / 10 min. The first corelayer can comprise less than 30 wt.% of the low density polyethylene of the first core layer or from 10 to 30 wt.%, based on the total weight of the first core layer.

[0025] In some embodiments, the linear low density of the first core layer has a density between 0.910 to 0.930 g / cc and a melt index (I2) of 0.2 to 5.0 g / 10 min. In some embodiments, the linear low density polyethylene of the first core layer has a density of a lower limit of 0.910, 0.912, 0.914, 0.916, 0.918, or 0.920 g / cc and an upper limit of 0.928, 0.926, 0.924, or 0.922 g / cc. In some embodiments, the linear low density polyethylene of the first core layer has a melt index (I2) of from 0.2 to 5.0 g / 10 min, from 0.3 to 4.0 g / 10 min, 0.4 to 3.0 g / 10 min, 0.4 to 2.0 g / 10 min, or 0.5 to 2.0 g / 10 min. The first core layer can comprise at least 65 wt.% the linear low density polyethylene, or from 65 to 80 wt.% the linear lower density, based on the total weight of the first core layer. In some embodiments, the linear low density of the first core layer comprises 1 -octene.

[0026] The polyethylene elastomer of the first core layer has a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s. In some embodiments, the polyethylene elastomer of the first core layer has a lower limit density of 0.855, 0.860, 0.865 g / cc and an upper limit of 0.910, 0.905, 0.900, 0.895, 0.890, 0.885, 0.880 or 0.875 g / cc. In some embodiments, the polyethylene elastomer of the first core layer has a Brookfield Viscosity of less than 11.0 Pa.s, less than 10.0 Pa.s, less than 9.0 Pa.s, or less than 8.5 Pa.s, or from 6.0 to 11.0 Pa.s or 7.0 to 10.0 Pa.s. In some embodiments, the polyethylene elastomer of the first core layer has a melt index (I2) of greater than 500 g / 10 min. In some embodiments, the first core layer comprises less than 5 wt.% of the polyethylene elastomer, or from 1 to 4 wt.% of the polyethylene elastomer, based on the total weight of the first core layer.

[0027] In some embodiments, the multilayer film comprises a second core layer comprising a second low density polyethylene, a second linear low density polyethylene, and a second polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s. In such embodiments, the second low density polyethylene, the second linear low density polyethylene, and second polyethylene elastomer can be the same type or different type (e.g., Commercial name, density, melt index) of low density polyethylene, linear low density polyethylene, and polyethylene elastomer of the first core layer, as described herein. Similarly, in some embodiments, the multilayer film comprises a third core layer or even more core layers that comprise linear low density polyethylene, low density polyethylene, and / or polyethylene elastomer.

[0028] Outer Layer(s)

[0029] In some embodiments, the first outer layer and the second outer layer each comprise linear low density polyethylene and low density polyethylene. In some embodiments, the first outer layer and the second outer layer are void of polyethylene elastomer. In some embodiments, the first outer layer comprises at least 60 wt.% LLDPE, or at least 65 wt.% LLDPE, or at least 70 wt.% LLDPE, or from 60 to 80 wt.% LLDPE, based on the total weight of the first outer layer. In some embodiments, the first outer layer comprises less than 35 wt.% LDPE, less than 30 wt.% LDPE, less than 25 wt.% or less than 20 wt.% LDPE, based on the total weight of the first outer layer. In some embodiments, the first outer layer comprises at least 15 wt.% LDPE, at least 20 wt.% LDPE, or at least 25 wt.% LDPE, or at least 30 wt.% LDPE, or from 15 to 40 wt.% LDPE, based on the total weight of the first outer layer.

[0030] In some embodiments, the second outer layer comprises at least 60 wt.% LLDPE, or at least 65 wt.% LLDPE, or at least 70 wt.% LLDPE, or from 60 to 80 wt.% LLDPE, based on the total weight of the second outer layer. In some embodiments, the second outer layer comprises less than 35 wt.% LDPE, less than 30 wt.% LDPE, less than 25 wt.% or less than 20 wt.% LDPE, based on the total weight of the second outer layer. In some embodiments, the second outer layer comprises at least 15 wt.% LDPE, at least 20 wt.% LDPE, or at least 25 wt.% LDPE, or at least 30 wt.% LDPE, or from 15 to 40 wt.% LDPE, based on the total weight of the second outer layer. The first and second outer layers can comprise at least 95 wt.% or 97 wt.% or 99 wt.% ethylene-based polymers.

[0031] Commercially available low density polyethylene suitable for use in the multilayer films in accordance with embodiments disclosed herein include those commercially available from The Dow Chemical Company such as AGILITY™ AT 1604 Performance LDPE and LDPE 310E. Other commercially available low density polyethylene include Sabie 2100, Carmel Ipethene 4203, Braskem LD7000A, Celanese AT505, and Repsol PE-033.

[0032] Commercially available linear low density polyethylenes suitable for use in the multilayer film according to embodiments disclosed herein include those commercially available from The Dow Chemical Company such as DOWLEX™ 2645 and DOWLEX™ 2045G. Other commercially available linear low density polyethylene include Exceed 1018, Sabie Supeer 7118, Marlex 7109, Ineos LL8109, and Novapol PF0118.

[0033] Commercially available elastomers suitable for use in accordance with embodiments disclosed herein include such as AFFINITY™ Polyolefin Elastomer ENGAGE™ Polyolefin Elastomers, and INFUSE™ Olefin Block Copolymers (available from The Dow Chemical Company), EXACT™ Elastomers (available from ExxonMobil Chemical), Tafmer (available from Mitsui), Nexlene™ (available from SK Chemicals Co.), and Lucene™ (available LG Chem Ltd.).Other Lavers

[0034] In addition to the first outer layer, the second outer layer, and the first core layer, the multilayer film can comprise additional core layers as disclosed herein.Process for Making Multilayer Film

[0035] The multilayer film can be formed via a film casting or blown-film processes. In some embodiments, the multilayer film is a blown film. In some embodiments, the film is a silobag. A silobag can be produced through a blown film process and used for the storage and preservation of grains and other agricultural products. The blown film process can be used by extruding molten polymer through a circular die to form a continuous tube of plastic, which is then inflated to create a film. The film can subsequently wound onto rolls and can be converted into silobags of various sizes. A silobag can be from 5 to 12 feet in diameter and can be from 200 to 240 feet long.

[0036] Films disclosed herein and silbags can have a desirable balance of MD tear propagation, high puncture resistance, dart drop, and creep. The properties and components of the film in accordance with embodiments disclosed herein can produce a film and silbag offering excellent durability, puncture resistance, and flexibility, making them ideal for protecting stored products from environmental factors such as moisture, pests, and UV radiation. In accordance with embodiments disclosed herein, the multilayer film can have at least one of the following properties: a Dart Drop impact resistance of at least 1450 g (or at least 1470 g); an MD Elmendorf Tear of at least 4700 gf (or at least 4800 gf or at least 4900 gf); a Puncture Elongation at Break of at least 80 mm; a Puncture Energy at Break of at least 14.0 I (or at least 15.0 I); a Puncture Force of at least 300 N (or at least 310 N); a Puncture Resistance of at least 7.0 J / cc (or at least 7.5 I / cc). Without being bound by theory, the composition of the one or more core layers with the specific low amount and type of elastomercan deliver a film having the desirable properties recited herein. The composition and film can be suitable for recycling steams as well in being formed from ethylene-based polymers.

[0037] Silobag applications can demand a high MD tear propagation resistance (critical during the unloading process), and balance of puncture resistance (as silobags are laid on the ground in the field where an imperfection on the soil can perforate the bag, losing the preservation conditions required for the grains) and dart drop.

[0038] A process for making a multilayer film according to embodiments disclosed herein comprises extruding a first outer layer, a second outer layer, and one or more core layers to form a multilayer film, wherein the one or more core layers is positioned between the first outer layer and the second outer layer; the one or more core layers comprises at least 95 wt.% ethylene-based polymers, at least 65 wt.% linear low density polyethylene, less than 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers, wherein a first core layer comprises a combination of a low density polyethylene, a linear low density polyethylene, and a polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s. In embodiments where the multilayer film is a blown film, the process can include extruding through a circular die to form a tube and inflating a tube to form the film.

[0039] The process can be adjusted to form films as described herein, for example, extruding additional layers, adding more or less amounts of polymer compositions, adjusting the layer ratios, and adjusting the thickness of the films.

[0040] TEST METHODS

[0041] Density

[0042] Density is measured in accordance with ASTM D792 and expressed in grams / cm3(g / cm3or g / cc).

[0043] Melt Index (I2)

[0044] The procedure described in ASTM D1238 is followed to determine the melt index of the low density polyethylene and linear low density polyethylene. Method B of ASTM D1238 is used. Units are g / 10 min or dg / min.

[0045] PUNCTURE

[0046] The test is conducted in Instron - 5982 (Load Cell: 500 N) equipment which punctures the film with a stainless steel prove until it is pierced. The test reports puncture energy (J), puncture force (N), puncture resistance (J / cc), puncture elongation (mm) and thickness of the film tested. The test follows ASTM D-5748.

[0047] DART DROP IMPACT

[0048] The test is conducted in a Die Punch - 6054 - CEAST equipment which releases a standardized dart (following ASTM D 1709) of 1350 grams from 0.66 meters of height (for method A) and a dart of 2000 grams from 1.5 meters of height (for method B). The tests report the impact in grams.

[0049] ELMENDORF TEAR

[0050] The test is conducted in an Elmendorf - 83200000 ED30 - CEAST - Pro tear -81369 - Thwing Albert equipment (following ASTM D1922), which with a blade with weight, tears the tested film. The test reports tear resistance in grams force. The test is conducted in Machine and Cross direction of the film.

[0051] EXAMPLES

[0052] Materials Used

[0053] The following materials are included in the examples discussed below.

[0054] Table 1. MaterialsResin Melt Index Density Brookfield Type [g / lOmin] [g / cm3] Viscosity[Pa.s]LDPE™ 203M 0.30 0.921 - LDPE DOWLEX™ TG 0.95 0.919 - LLDPE2085AFFINITY™ GA >500 0.870 8.2 Elastomer 1900AFFINITY™ 1.00 0.904 - Elastomer 1888ENGAGE™ 8100 1.00 0.870 - ElastomerENGAGE™ 8200 5.00 0.870 - Elastomer

[0055] Films are extruded on a Dr. Collin blown film line located in Pack Studios (Jundiai, Sao Paulo). Line setting and processing conditions available in Table 2. The first and second outer layers of each of the films are made of 75% DOWLEX™ TG 2085B and 25% LDPE 203M.

[0056] Table 2. Blown Film Line Setting and Processing conditions.Parameter ValueTotal thickness 230(pm)Die gap (mm) 1.8Blow Up Ratio 2.0Total Output (kg / h) 22

[0057] Tables 3 - Core Layer CompositionsSample Inventive Film Inventive Film Inventive Film Inventive Film1 2 3 4Core 1 75% 75% 73.5% 72%DOWLEX™ DOWLEX™ DOWLEX™ DOWLEX™(20%) TG 2085B TG 2085B TG 2085B TG 2085B25% LDPE 25% LDPE 25% LDPE 25% LDPE 203M 203M 203M 203M1.5% 3%AFFINITY™ AFFINITY™GA 1900 GA 1900Core 2 72% 70% 75% 75%DOWLEX™ DOWLEX™ DOWLEX™ DOWLEX™(20%) TG 2085B TG 2085B TG 2085B TG 2085B25% LDPE 25% LDPE 25% LDPE 25% LDPE 203M 203M 203M 203M3% 5%AFFINITY™ AFFINITY™GA 1900 GA 1900Core 3 75% 75% 73.5% 72%DOWLEX™ DOWLEX™ DOWLEX™ DOWLEX™(20%) TG 2085B TG 2085B TG 2085B TG 2085B25% LDPE 25% LDPE 25% LDPE 25% LDPE 203M 203M 203M 203M1.5% 3%AFFINITY™ AFFINITY™ GA 1900 GA 1900Sample Comparative 1 Comparative 2 Comparative 3 Comparative 4 Core 1 75% 73.5% 73.5% 73.5%DOWLEX™ TG DOWLEX™ TG DOWLEX™ TG DOWLEX™ TG (20%) 2085B 2085B 2085B 2085B 25% LDPE 25% LDPE 25% LDPE 25% LDPE 203M 203M 203M 203M1.5% AFFINITY 1.5% ENGAGE 1.5% ENGAGE 1888 8100 8200 Core 2 75% 75% 75% 75%DOWLEX™ TG DOWLEX™ TG DOWLEX™ TG DOWLEX™ TG (20%) 2085B 2085B 2085B 2085B 25% LDPE 25% LDPE 25% LDPE 25% LDPE 203M 203M 203M 203M Core 3 75% 73.5% 73.5% 73.5%DOWLEX™ TG DOWLEX™ TG DOWLEX™ TG DOWLEX™ TG (20%) 2085B 2085B 2085B 2085B 25% LDPE 25% LDPE 25% LDPE 25% LDPE 203M 203M 203M 203M1.5% AFFINITY 1.5% ENGAGE 1.5% ENGAGE 1888 8100 8200

[0058] Tables 4. Film PropertiesSample Inventive Inventive Inventive Inventive Film 1 Film 2 Film 3 Film 4 ResultDart Drop Impact1490 1483 1490 1450 Resistance [g]MD Elmendorf Tear [gf] 5013 4842 4674 4574 Puncture Elongation at88 84 92 85 Break [mm]Puncture Energy at Break15.4 15.2 17.7 16.2 [J]Puncture Force [N] 330 321 344 325 Puncture Resistance [J / cc] 7.9 8.0 9.7 9.0Sample Comparative 1 Comparative 2 Comparative 3 Comparative 4 Dart Drop Impact Resistance1350 1367 1550 1450 [g]MD Elmendorf Tear [gf] 4547 4751 4685 4640 Puncture Elongation at75 111 106 100 Break [mm]Puncture Energy at Break [J] 12.8 17.3 15.1 13.8 Puncture Force [N] 303 234 209 202Puncture Resistance [J / cc] 6.8 8.7 7.7 6.9

Claims

We Claim:

1. A multilayer film comprising a first outer layer, a second outer layer, and one or more core layers, the one or more core layers positioned between the first outer layer and the second outer layer; the one or more core layers comprises at least 95 wt.% ethylene-based polymers, at least 65 wt.% linear low density polyethylene, less than 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers, wherein a first core layer comprises a combination of a low density polyethylene, a linear low density polyethylene, and a polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s.

2. The multilayer film of any one of the preceding claims, wherein the linear low density of the first core layer has a density between 0.910 to 0.930 g / cc and a melt index (I2) of 0.2 to 5.0 g / 10 min.

3. The multilayer film of any one of the preceding claims, wherein the low density polyethylene of the first core layer has a density between 0.910 to 0.930 g / cc and a melt index (I2) of 0.1 to 7.0 g / 10 min.

4. The multilayer film of any one of the preceding claims, wherein the polyethylene elastomer of the first core layer has a melt index (12) of greater than 500 g / 10 min.

5. The multilayer film of any one of the preceding claims, wherein the multilayer film comprises a second core layer comprises a second low density polyethylene, a second linear low density polyethylene, a second polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s.

6. The multilayer film of any one of the preceding claims, wherein the first outer layer and the second outer layer each comprise linear low density polyethylene and low density polyethylene.

7. The multilayer film of any one of the preceding claims, wherein the multilayer film comprises less than 3 wt.% polyethylene elastomer, based on the total weight of the film.

8. The multilayer film of any one of the preceding claims, wherein the multilayer film comprises at least 95 wt.% ethylene-based polymers.

9. The multilayer film of any one of the preceding claims, wherein the one or more core layers comprises from 65 to 80 wt.% linear low density polyethylene, 20 to 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers.

10. The multilayer film of any one of the preceding claims, wherein the multilayer film comprises from 65 to 80 wt.% linear low density polyethylene, 20 to 30 wt.% low density polyethylene, and less than 3 wt.% polyethylene elastomer, based on the total weight of the film.

11. The multilayer film of any one of the preceding claims, wherein the linear low density of the first core layer comprises 1 -octene.

12. The multilayer film of any one of the preceding claims, wherein the multilayer film has a thickness between 180 to 260 microns.

13. The multilayer film of any one of the preceding claims, wherein the one or more core layers comprise at least 40% of the total thickness of the film.

14. The multilayer film of any one of the preceding claims, wherein the multilayer film has at least one of the following properties: a Dart Drop impact resistance of at least 1450 g; an MD Elmendorf Tear of at least 4700 gf; a Puncture Elongation at Break of at least 80 mm; a Puncture Energy at Break of at least 14.0 J; a Puncture Force of at least 300 N ; a Puncture Resistance of at least 7.0 J / cc.

15. The multilayer film of any one of the preceding claims, wherein the film is a blown film.

16. The multilayer film of any one of the preceding claims, wherein the film is a silobag.

17. A process for making a multilayer film comprising: extruding a first outer layer, a second outer layer, and one or more core layers to form a multilayer film, wherein the one or more core layers is positioned between the first outer layer and the second outer layer; the oneor more core layers comprises at least 95 wt.% ethylene-based polymers, at least 65 wt.% linear low density polyethylene, less than 30 wt.% low density polyethylene, and less than 5 wt.% polyethylene elastomer, based on the total weight of the one or more core layers, wherein a first core layer comprises a combination of a low density polyethylene, a linear low density polyethylene, and a polyethylene elastomer having a density of from 0.855 g / cc to 0.910 g / cc and a Brookfield Viscosity of less than 12.0 Pa.s.

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