Multilayer structures and articles having a coating layer

Abstract

Multilayer structures and articles formed therefrom are provided. The multilayer structures according to embodiments disclosed herein include a substrate layer and a coating layer, where the substrate layer is coated with the coating layer. The coating layer includes a blend of high-pressure low-density polyethylene and a masterbatch composition. When the coating layer is coated onto the substrate layer, the coating layer can have improved neck-in reduction and drawdown retention or improvement during processing.

Description

Technical Field

[0001] The present invention relates to a multilayer structure including a base material layer and a coating layer, an article including such a multilayer structure, and a method for producing such a multilayer structure.

[0002] Introduction Multilayer structures including an extruded coated substrate (i.e., a base material layer coated with a coating layer) are widely used in packaging applications. To produce such structures, a polyolefin coating can be adhered or coated onto the substrate via extrusion coating. The coating can improve or impart desirable properties (e.g., barrier properties, sealing properties, and toughness properties) when added to the base material layer. However, there are challenges in the production and manufacture of extruded coated substrates. For example, low-density polyethylene is often used as a polyolefin coating due to its high melt strength and the presence of long-chain branches. However, by extruding and coating low-density polyethylene onto a substrate (e.g., a film), an increase in neck-in can occur when the production line is operating at its maximum target speed. Therefore, there is still a need for a multilayer structure including a coating layer and resin design that exhibits a reduction in neck-in while maintaining or improving drawdown performance.

Summary of the Invention

[0003] The present invention provides a multilayer structure including a base material layer and a coating layer, wherein the base material layer is coated with the coating layer. According to an embodiment, the coating layer includes a polyethylene composition including high-pressure low-density polyethylene and a masterbatch composition, and when the coating layer is coated onto the base material layer, the coating layer can exhibit desirable properties such as a reduction in neck-in while maintaining or improving drawdown.

[0004] In one embodiment, the present invention comprises (a) a substrate layer including a base material and (b) a coating layer including a polyethylene composition, wherein the polyethylene composition is (i) 0.916 g / cm³ 3 ~0.940g / cm 3 (ii) a masterbatch composition comprising (ii) a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density in the range of 0.900 g / cm³ 3 ~0.970g / cm 3 The present invention provides a multilayer structure comprising a coating layer and a substrate layer coated with the coating layer, the masterbatch composition comprising a masterbatch composition having a density in the range of 0.01 g / 10 min to a melt index in the range of 0.01 g / 10 min to 100 g / 10 min.

[0005] In another embodiment, the present invention provides an article such as packaging that includes any of the multilayer structures of the present invention disclosed herein.

[0006] In another aspect, the present invention provides a method for forming a multilayer structure of the present invention, the method comprising (a) 0.916 g / cm³ 3 ~0.940g / cm 3 (b) to provide high-pressure, low-density polyethylene having a density in the range of , a melt index (I2) of 2.0 to 30.0 g / 10 min, and less than 0.20 vinyl groups per 1,000 total carbon atoms; and to provide a masterbatch composition comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density of 0.900 g / cm³ 3 ~0.970g / cm 3The invention provides (c) a polyethylene composition having a density in the range of 0.01 g / 10 min to 100 g / 10 min, and (d) a polyethylene composition formed by reacting high-pressure low-density polyethylene with a masterbatch composition, and (c) a multilayer structure formed by extruding the polyethylene composition as a coating layer onto a substrate layer containing a substrate.

[0007] These and other embodiments are described in more detail in “Modes for Carrying Out the Invention.” [Modes for carrying out the invention]

[0008] The embodiments of the multilayer structures, articles, and methods for producing the multilayer structures disclosed are described in more detail below. However, this disclosure should not be construed as limiting the embodiments described below.

[0009] As used herein, the term “polymer” means a polymer compound prepared by polymerizing monomers, whether of the same or different types. Thus, the general term polymer encompasses the terms homopolymer (used to refer to a polymer prepared from only one type of monomer) and copolymer or interpolymer. Trace amounts of impurities (e.g., catalyst residue) may be incorporated into and / or within the polymer. A polymer may be a single polymer, a polymer blend, or a polymer mixture containing a mixture of polymers formed in situ during polymerization.

[0010] As used herein, the terms "polyethylene" or "ethylene polymer" shall mean a polymer containing units derived from more than a majority (more than 50 mol%) of ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). General forms of polyethylene known in the art include Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), Ultra Low Density Polyethylene (ULDPE), Very Low Density Polyethylene (VLDPE), single-site catalyst linear low density polyethylene (m-LLDPE) including both linear low density resin and substantially linear low density resin, ethylene-based plastomer (POP), and ethylene-based elastomer (POE), Medium Density Polyethylene (MDPE), and High Density Polyethylene (HDPE).

[0011] As used herein, the term "high pressure low density polyethylene" shall mean polyethylene that is partially or wholly polymerized or copolymerized alone or with other monomers at a pressure above 14,500 psi (100 MPa) using a free radical initiator such as a peroxide in an autoclave or a tubular reactor (see, for example, U.S. Patent No. 4,599,392, which is incorporated herein by reference). As used herein, high pressure low density polyethylene has a density in the range of 3 ~0.916 g / cm 3 to 0.940 g / cm.

[0012] As used herein, the term “multilayer structure” refers to any structure having two or more layers. For example, a multilayer structure may have two, three, four, five, or more layers. A multilayer structure may be described as having layers specified by letters. For example, a three-layer structure having a core layer B and two outer layers A and C may be indicated as A / B / C. Similarly, a structure having two core layers B and C and two outer layers A and D would be indicated as A / B / C / D. Multilayer structures disclosed herein include structures that include a coating layer and a substrate layer.

[0013] The terms “comprising,” “including,” and “having,” and their derivatives, are not intended to exclude the presence of any additional components, processes, or procedures, whether or not they are specifically disclosed. To avoid any doubt, all compositions claimed through the use of the term “comprising” may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless otherwise stated. In contrast, the term “consisting essentially of” excludes any other components, processes, or procedures from the scope of any subsequent description, except those not essential to operability. The term “consisting of” excludes any components, processes, or procedures not specifically described or listed.

[0014] In embodiments, the present invention comprises (a) a substrate layer containing a base material and (b) a coating layer containing a polyethylene composition, wherein the polyethylene composition is (i) 0.916 g / cm³ 3 ~0.940g / cm 3(ii) a masterbatch composition comprising (ii) a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density in the range of 0.900 g / cm³ 3 ~0.970g / cm 3 The present invention provides a multilayer structure comprising a coating layer and a substrate layer coated with the coating layer, the masterbatch composition comprising a masterbatch composition having a density in the range of 0.01 g / 10 min to 100 g / 10 min. While not bound by any particular theory, it is believed that a blend of a specific high-pressure low-density polyethylene and a specific masterbatch composition having a free radical generator contributes to reducing neck-in and maintaining or improving drawdown compared to a multilayer structure comprising a coating layer having low-density polyethylene or linear low-density polyethylene without the blend.

[0015] The multilayer structure of the present invention may include a combination of two or more embodiments described herein.

[0016] In other embodiments, the present invention relates to articles such as packaging. In embodiments, the article comprises one of the multilayer structures of the present invention disclosed herein. The article of the present invention may comprise a combination of two or more embodiments described herein.

[0017] Base material layer The multilayer structure of the present invention includes a substrate layer containing a substrate. The coating layer is applied to the substrate layer using techniques known in the art, such as extrusion coating (i.e., the substrate layer is coated with the coating layer).

[0018] In the embodiment, the substrate of the substrate layer may include at least one of the following: film, nonwoven fabric, woven fabric, scrim, foil, carpet, plastic, saran, paper, cellulose, or metal.

[0019] coating layer The multilayer structure of the present invention includes a coating layer. The coating layer includes a polyethylene composition. The polyethylene composition is (i) 0.916 g / cm³ 3 ~0.940g / cm 3 (ii) a masterbatch composition comprising (ii) high-pressure low-density polyethylene having a density in the range of , a melt index (I2) in the range of 2.0 to 30.0 g / 10 min, and less than 0.20 vinyl groups per 1,000 total carbon atoms, and (ii) a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density of 0.900 g / cm³ 3 ~0.970g / cm 3 The multilayer structure comprises a masterbatch composition having a density in the range of 0.01 g / 10 min to 100 g / 10 min and a melt index (I2) in the range of 0.01 g / 10 min to 100 g / 10 min. The multilayer structure includes a coating layer that enhances neck-in reduction and maintains or improves drawdown.

[0020] The polyethylene composition comprises high-pressure low-density polyethylene. In embodiments, the polyethylene composition comprises 90 to 99.5 weight percent (W%) of high-pressure low-density polyethylene and 0.5 to 10 weight percent of a masterbatch composition. All individual values ​​and partial ranges of the 90 to 99.5 weight percent of high-pressure low-density polyethylene are disclosed and incorporated herein. For example, the polyethylene composition may contain 90 to 99.5 weight percent, 92 to 99.5 weight percent, 95 to 99.5 weight percent, or 96 to 99.5 weight percent of high-pressure low-density polyethylene, where weight percent (W%) is based on the total weight of the polyethylene composition. Similarly, all individual values ​​and partial ranges of the 0.5 to 10 weight percent of a masterbatch composition are disclosed and incorporated herein. For example, the polyethylene composition may contain 0.5 to 10 weight percent, 0.5 to 8 weight percent, 0.5 to 5 weight percent, or 0.5 to 4 weight percent of a masterbatch composition, where weight percent (W%) is based on the total weight of the polyethylene composition.

[0021] In this embodiment, the high-pressure low-density polyethylene of the polyethylene composition is 0.916 g / cm³. 3 ~0.940g / cm 3 It has a density of 0.916 g / cm³. 3 ~0.940g / cm 3 All individual values ​​and subranges of are disclosed and included herein. For example, high-pressure low-density polyethylene is 0.916 g / cm³. 3 ~0.940g / cm 3 , 0.916 g / cm³ 3 ~0.935g / cm 3 , 0.916 g / cm³ 3 ~0.930g / cm 3 , 0.916 g / cm³ 3 ~0.925g / cm 3 , or 0.916 g / cm³ 3 ~0.920g / cm 3 It can have a density of .

[0022] In embodiments, the high-pressure low-density polyethylene of the polyethylene composition has a melt index (I2) in the range of 2.0 to 30.0 g / 10 min. All individual values ​​and partial ranges of 2.0 to 30.0 g / 10 min are disclosed and incorporated herein. For example, the high-pressure low-density polyethylene may have a melt index (I2) in the range of 2.0 to 30.0 g / 10 min, 2.0 to 20 g / 10 min, or 0.2 to 10 g / 10 min.

[0023] In the embodiments, the high-pressure low-density polyethylene of the polyethylene composition has fewer than 0.20 vinyl groups per 1,000 total carbon atoms. All values ​​and partial ranges of fewer than 0.20 vinyl groups per 1,000 total carbon atoms are disclosed and included herein. For example, high-pressure low-density polyethylene may have fewer than 0.20 vinyl groups per 1,000 total carbon atoms, fewer than 0.18 vinyl groups per 1,000 total carbon atoms, fewer than 0.16 vinyl groups per 1,000 total carbon atoms, fewer than 0.14 vinyl groups per 1,000 total carbon atoms, fewer than 0.12 vinyl groups per 1,000 total carbon atoms, fewer than 0.10 vinyl groups per 1,000 total carbon atoms, fewer than 0.08 vinyl groups per 1,000 total carbon atoms, or fewer than 0.06 vinyl groups per 1,000 total carbon atoms, and vinyl unsaturation can be measured according to the test methods described below.

[0024] In one embodiment, high-pressure low-density polyethylene can be polymerized in an autoclave reactor. In another embodiment, high-pressure low-density polyethylene can be polymerized in a tubular reactor.

[0025] Examples of high-pressure, low-density polyethylenes that can be used in the polyethylene composition of the coating layer in some embodiments include DOW® LDPE 772 and AGILITY® (e.g., AGILITY® EC7000 and AGILITY® EC7080) high-pressure, low-density polyethylenes, which are commercially available from The Dow Chemical Company (Midland, MI).

[0026] The polyethylene composition comprises a masterbatch composition containing a free radical generator and a polyethylene resin. In some embodiments, the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy greater than -250 kJ / mol (i.e., less than -250 kJ / mol). In some embodiments, the free radical generator has a half-life of less than 175 seconds, 150 seconds, or 125 seconds at 220°C. In other embodiments, the free radical generator has a half-life of 60 to 200 seconds, 60 to 175 seconds, 60 to 150 seconds, 60 to 125 seconds, or 60 to 120 seconds at 220°C.

[0027] In embodiments, the free radical generator may have a molecular weight of 200 to 1,000 daltons. All individual values ​​and subranges of 200 to 1,000 daltons are included and disclosed herein. For example, in some embodiments, the free radical generator may have a molecular weight of 225 to 1,000, 250 to 1,000, or 250 to 700.

[0028] In embodiments, the free radical generator is present in an amount ranging from 5 ppm to 1000 ppm relative to the total amount of polyethylene resin. All individual values ​​and subranges of 5 to 1000 ppm are included and disclosed herein, and for example, the amount of the free radical generator relative to the total amount of polyethylene resin may range from a lower limit of 5, 10, 20, 30, 50, 80, 100, 200, 300, 400, 500, 600, 700, 800, or 900 ppm to an upper limit of 15, 25, 30, 35, 50, 60, 65, 75, 100, 150, 250, 350, 450, 550, 650, 750, 850, 950, or 1000 ppm.

[0029] In the embodiments described herein, the free radical generator may be a cyclic peroxide. A suitable example of a cyclic peroxide may be represented by the following formula. [ka] In the formula, R1 to R6 are independently hydrogen- or inertly substituted or unsubstituted C1 to C20 alkyl, C3 to C20 cycloalkyl, C6 to C20 aryl, C7 to C20 aralkyl, or C7 to C20 alkaryl. Representative inert substituents included in R1 to R6 are hydroxyl, C1 to C20 alkoxy, linear or branched C1 to C20 alkyl, C6 to C20 aryloxy, halogen, ester, carboxyl, nitrile, and amide. In some embodiments, R1 to R6 are independently lower alkyls, for example, C1 to C10 alkyl or C1 to C4 alkyl.

[0030] Some of the cyclic peroxides described herein are commercially available, but otherwise they can be prepared by contacting a ketone with hydrogen peroxide, as described in U.S. Patent No. 3,003,000; Uhlmann, 3rd Ed., Vol. 13, pp. 256-57 (1962); the paper, “Studies in Organic Peroxides XXV Preparation, Separation and Identification of Peroxides Derived from Methyl Ethyl Ketone and Hydrogen Peroxide,” Milas, NA and Golubovic, A., J. Am. Chem., Soc, Vol. 81, pp. 5824-26 (1959); “Organic Peroxides”, Swern, D. editor, Wiley-Interscience, New York (1970); and Houben-Weyl Methoden der Organische Chemie, El 3, Volume 1, page 736.

[0031] Other examples of cyclic peroxides include those derived from acetone, methyl amyl ketone, methyl heptyl ketone, methyl hexyl ketone, methyl propyl ketone, methyl butyl ketone, diethyl ketone, methyl ethyl ketone, methyl octyl ketone, methyl nonyl ketone, methyl decyl ketone, and methyl undecyl ketone. Cyclic peroxides can be used individually or in combination with each other.

[0032] In some embodiments, the cyclic peroxide may be 3,6,9-triethyl-3-6-9-trimethyl-1,4,7-triperoxonane, which is commercially available from AkzoNobel under the trade name TRIGONOX301. The cyclic peroxide used herein may be a liquid, solid, or paste, depending on the melting points of the peroxide and the diluent supported therein (if any).

[0033] The polyethylene resin in the masterbatch composition is 0.900 g / cm³. 3 ~0.970g / cm 3 It has a density in the range of 0.900 g / cm³ and a melt index (I2) in the range of 0.01 g / 10 min to 100 g / 10 min. 3 ~0.970g / cm 3 All individual values ​​and subranges of densities in the range of 0.01 g / 10 min to 100 g / 10 min and melt indices in the range of 0.01 g / 10 min to 100 g / 10 min are included and disclosed herein. For example, in some embodiments, the densities are 0.900, 0.902, 0.905, 0.907, 0.910, 0.912, 0.915, 0.920, 0.925, 0.930, 0.935, or 0.940 g / cm³. 3 From the lower limit, 0.970, 0.965, 0.960, 0.955, 0.950, 0.945, 0.942, 0.940, 0.937, 0.935, 0.930, 0.927, 0.925, 0.922, or 0.920 g / cm³ 3 This is within the range up to the upper limit. In other embodiments, the density is 0.905 g / cm³. 3 ~0.965g / cm 3 , 0.905 g / cm³ 3 ~0.960g / cm 3, 0.907 g / cm³ 3 ~0.960g / cm 3 , 0.910 g / cm³ 3 ~0.955 g / cm³ 3 , 0.910 g / cm³ 3 ~0.950g / cm 3 , 0.910 g / cm³ 3 ~0.947 g / cm³ 3 , 0.910 g / cm³ 3 ~0.945g / cm 3 , 0.910 g / cm³ 3 ~0.9420 g / cm³ 3 , or 0.910 g / cm³ 3 ~0.940g / cm 3 The range is as follows: For example, in some embodiments, the melt index (I2) ranges from a lower limit of 0.01, 0.05, 0.1, 0.5, 1, 3, 5, 7, 10, 12, 15, 18, 20, 23, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 to an upper limit of 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 27, 25, 22, 20, 17, 15, 12, 10, 8, 5, 2, 1, 0.9, 0.7, or 0.5. In other embodiments, the melt index (I2) is in the range of 0.05g / 10 min to 30g / 10 min, 0.1g / 10 min to 30g / 10 min, 0.1g / 10 min to 25g / 10 min, 0.1g / 10 min to 20g / 10 min, 0.1g / 10 min to 18g / 10 min, 0.1g / 15 min to 30g / 10 min, 0.25g / 10 min to 15g / 10 min, 0.25g / 10 min to 12g / 10 min, 0.25g / 10 min to 10g / 10 min, 0.25g / 10 min to 8g / 10 min, and 0.25g / 10 min to 5g / 10 min.

[0034] The polyethylene resin may be low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), or a combination thereof. In some embodiments, the polyethylene resin is LDPE. In other embodiments, the polyethylene resin is LLDPE. In further embodiments, the polyethylene is MDPE or HDPE.

[0035] In embodiments herein where the polyethylene resin is LLDPE, the LLDPE may be homogeneous branched or heterogeneous branched, and / or monomodal or multimodal (e.g., bimodal) polyethylene. Linear low-density polyethylene includes ethylene homopolymers, interpolymers of ethylene and at least one comonomer, and blends thereof. Examples of suitable comonomers include alpha-olefins. Suitable alpha-olefins may contain 3 to 20 carbon atoms (C3 to C20). For example, the alpha-olefin may be C4 to C20 alpha-olefin, C4 to C12 alpha-olefin, C3 to C10 alpha-olefin, C3 to C8 alpha-olefin, C4 to C8 alpha-olefin, or C6 to C8 alpha-olefin. In some embodiments, the linear low-density polyethylene is an ethylene / alpha-olefin copolymer, and the alpha-olefin is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, and 1-decene. In other embodiments, the linear low-density polyethylene is an ethylene / alpha-olefin copolymer, and the alpha-olefin is selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene. In further embodiments, the linear low-density polyethylene is an ethylene / alpha-olefin copolymer, and the alpha-olefin is selected from the group consisting of 1-hexene and 1-octene.

[0036] Linear low-density polyethylene can be produced via a gas-phase, liquid-phase, or slurry polymerization process, or any combination thereof, using any type of reactor or reactor configuration known in the art, such as a fluidized bed gas-phase reactor, loop reactor, stirred-tank reactor, or batch reactor, in parallel, in series, and / or any combination thereof. In some embodiments, gas-phase or slurry-phase reactors are used. Preferred linear low-density polyethylene may be produced according to the processes described on pages 15-17 and 20-22 of International Publication 2005 / 111291(A1) (incorporated herein by reference). Catalysts used to produce the linear low-density polyethylene described herein may include Ziegler-Natta, chromium, metallocene, constrained geometry, or single-site catalysts. Examples of suitable linear low-density polyethylenes include substantially linear ethylene polymers, as further defined and incorporated by reference in U.S. Patents 5,272,236, 5,278,272, 5,582,923, 5,733,155, and European Patent No. 2,653,392; homogeneous branched linear ethylene polymer compositions, such as those in U.S. Patent No. 3,645,992, incorporated by reference; heterogeneous 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 U.S. Patent No. 3,914,342 or U.S. Patent No. 5,854,045), all incorporated by reference.In some embodiments, the linear low-density polyethylene includes, for example, ELITE® 5100G or 5400G resin, ELITE® AT 6401, ATTANE® 4201 or 4202 resin, AFFINITY® 1840, and DOWLEX® 2020, 2045G, 2049G, or 2685 resin, as well as ELITE®, ELITE® AT, ATTANE®, AFFINITY®, FLEXOMER®, or DOWLEX® resins sold by The Dow Chemical Company; for example, EXCEED® 1012, 1018, or 1023JA resin, and ENABLE® 27-03, 27-05, or 35-05 resin, as well as EXCEED® or ENABLE® resins sold by Exxon Mobil Corporation; for example, LLDPE LF1020 or HIFOR Examples include linear low-density polyethylene resins sold by Westlake Chemical Corporation, including Xtreme® SC74836 resin; linear low-density polyethylene resins sold by LyondellBasell Industries, including, for example, PETROTHENE® GA501 and LP540200 resins, and ALATHON® L5005 resin; linear low-density polyethylene resins sold by Nova Chemicals Corp., including, for example, SCLAIR® FP120 and NOVAPOL® TF-Y534; linear low-density polyethylene resins sold by Chevron Phillips Chemical Company, LLC, including, for example, mPACT® D139 or D350 resin and MARFLEX® HHM TR-130 resin; and linear low-density polyethylene resins sold by Borealis AG, including, for example, BORSTAR® FB 2310 resin.

[0037] In embodiments herein where the polyethylene resin is MDPE, the MDPE may be an ethylene homopolymer or a copolymer of ethylene and alpha-olefin. Suitable alpha-olefins may include those containing 3 to 20 carbon atoms (C3 to C20). For example, the alpha-olefin may be a C4 to C20 alpha-olefin, a C4 to C12 alpha-olefin, a C3 to C10 alpha-olefin, a C3 to C8 alpha-olefin, a C4 to C8 alpha-olefin, or a C6 to C8 alpha-olefin. In some embodiments, the MDPE is an ethylene / alpha-olefin copolymer, and the alpha-olefin is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, and 1-decene. In other embodiments, the MDPE is an ethylene / alpha-olefin copolymer, and the alpha-olefin is selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene. MDPE is 0.923 g / cm³ 3 ~0.935g / cm 3 It may have a density of . All individual values ​​and subranges are included and disclosed herein.

[0038] MDPE may be prepared by a gas-phase, liquid-phase, or slurry polymerization process, or any combination thereof, using any type of reactor or reactor configuration known in the art, such as a fluidized bed gas-phase reactor, loop reactor, stirred-tank reactor, or batch reactor, in parallel, series, and / or any combination thereof. In some embodiments, a gas-phase or slurry-phase reactor is used. In some embodiments, MDPE is prepared in a solution process operating in either parallel or series dual-reactor mode. MDPE can also be prepared by a high-pressure, free-radical polymerization process. A method for preparing MDPE by high-pressure, free-radical polymerization can be found in U.S. Patent Application Publication 2004 / 0054097 (incorporated herein by reference) and can be carried out in an autoclave or tubular reactor, or any combination thereof. Catalysts used to prepare the MDPE described herein may include Ziegler-Natta, metallocene, constrained geometry, single-site catalysts, or chromium-based catalysts. Examples of suitable MDPE resins include resins sold by The Dow Chemical Company, e.g., DOWLEX® 2038.68G or DOWLEX® 2042G; resins sold by LyondellBasell Industries (Houston, TX), e.g., PETROTHENE® L3035; ENABLE® resins sold by The ExxonMobil Chemical Company (Houston, TX); resins sold by Chevron Phillips Chemical Company LP, e.g., MARFLEX® TR-130; and resins sold by Total Petrochemicals & Refining USA Inc., e.g., HF 513, HT 514, and HR 515. Other exemplary MDPE resins are described in U.S. Patent Application Publication No. 2014 / 0255674 (incorporated herein by reference).

[0039] In embodiments herein where the polyethylene resin is HDPE, the HDPE may also be an ethylene homopolymer or a copolymer of ethylene and alpha-olefin. Suitable alpha-olefins may include those containing 3 to 20 carbon atoms (C3 to C20). For example, the alpha-olefin may be a C4 to C20 alpha-olefin, a C4 to C12 alpha-olefin, a C3 to C10 alpha-olefin, a C3 to C8 alpha-olefin, a C4 to C8 alpha-olefin, or a C6 to C8 alpha-olefin. In some embodiments, the HDPE is an ethylene / alpha-olefin copolymer, and the alpha-olefin is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, and 1-decene. In other embodiments, the HDPE is an ethylene / alpha-olefin copolymer, and the alpha-olefin is selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene. The amount of comonomer used will depend on the desired density of the HDPE polymer and the specific copolymer selected, taking into account processing conditions such as temperature and pressure, as well as other factors such as the presence or absence of telomers, as will be apparent to those skilled in the art familiar with this disclosure. The HDPE is 0.935 g / cm³. 3 ~0.975g / cm 3 It may have a density of . All individual values ​​and subranges are included and disclosed herein.

[0040] HDPE may be produced by a gas-phase, liquid-phase, or slurry polymerization process, or any combination thereof, using any type of reactor or reactor configuration known in the art, such as a fluidized bed gas-phase reactor, loop reactor, stirred-tank reactor, or batch reactor, in parallel, series, and / or any combination thereof. In some embodiments, a gas-phase or slurry-phase reactor is used. In some embodiments, HDPE is produced in a solution process operating in either parallel or series dual-reactor mode. Catalysts used to produce the HDPE described herein may include Ziegler-Natta, metallocene, constrained geometry, single-site catalysts, or chromium-based catalysts. HDPE may be unimodal, bimodal, or multimodal. Examples of commercially available HDPE resins include, for example, ELITE® 5940G, ELITE® 5960G, HDPE 35454L, HDPE82054, HDPEDGDA-2484 NT, DGDA-2485 NT, DGDA-5004 NT, and DGDB-2480 NT resins available from The Dow Chemical Company (Midland, MI); L5885 and M6020 HDPE resins available from Equistar Chemicals, LP; ALATHON® L5005 from LyondellBasell Industries (Houston, TX); and MARFLEX® HDPE HHM TR-130 from Chevron Phillips Chemical Company LP. Other example HDPE resins are described in U.S. Patent No. 7,812,094 (incorporated herein by reference).

[0041] Multilayer structure and method of forming it In some embodiments, the multilayer structure of the present invention includes a substrate layer and a coating layer deposited thereon (as described above). Incorporating a specific masterbatch and blend of high-pressure low-density polyethylene into the coating layer is advantageous in that it provides an improved reduction in neck-in during processing, which is beneficial to the processability of the structure.

[0042] A method for forming a multilayer structure is disclosed. The method is (a) 0.916 g / cm³ 3 ~0.940g / cm 3 (b) to provide high-pressure low-density polyethylene (as described above) having a density in the range of , a melt index (2) in the range of 2.0 to 30.0 g / 10 min, and less than 0.20 vinyl groups per 1,000 total carbon atoms; and (b) to provide a masterbatch composition (as described above) comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density of 0.900 g / cm³ 3 ~0.970g / cm 3 The invention provides (c) a polyethylene composition having a density in the range of 0.01 g / 10 min to 100 g / 10 min, and (d) a polyethylene composition formed by reacting high-pressure low-density polyethylene with a masterbatch composition, and (c) a multilayer structure formed by extruding the polyethylene composition as a coating layer onto a substrate layer containing a substrate.

[0043] The reaction of high-pressure low-density polyethylene with a masterbatch composition can be carried out in any conventional mixing apparatus in which the polymer is melted and mixed with the masterbatch. Suitable apparatuses are known to those skilled in the art and include, for example, mixers, kneaders, and extruders. In some embodiments, the reaction of high-pressure low-density polyethylene with a free radical generator is carried out in an extruder. The extruder may further be attached to an inflation film or cast film line. In some embodiments, the reaction of high-pressure low-density polyethylene with a free radical generator is carried out in an extruder attached to an inflation film or cast film line.

[0044] Exemplary extruders or kneaders include, for example, single-screw extruders, contra-rotating twin-screw extruders and co-rotating twin-screw extruders, planetary gear extruders, ring extruders, or co-kneaders. Suitable extruders and kneaders are further described, for example, in Handbuch der Kunststoftextrusion, Vol 1 Grundlagen, Editors F. Hensen, W. Knappe, H. Potente, 1989, pp. 3-7, ISBN. 3-446-14339-4 (Vol 2 Extrusionsanlagen 1986, ISBN 3-446-14329-7). In the embodiments described herein, the screw length may range from 1 to 60 times the screw diameter, or from 35 to 48 times the screw diameter. The rotational speed of the screw may range from 10 to 600 rotations per minute (rpm), or from 25 to 300 rpm. The maximum throughput depends on the screw diameter, rotational speed, and driving force. The process of the present invention can also be carried out at a level lower than the maximum throughput by varying the parameters described or by using a measuring device to deliver the dosage.

[0045] High-pressure low-density polyethylene and masterbatch may be reacted in a ratio of 60:40 to 99.9:0.1. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, high-pressure low-density polyethylene and masterbatch may be reacted in a ratio of 65:35 to 99.9:0.1, 65:35 to 99.9:0.1, 70:30 to 99.9:0.1, 75:25 to 99.9:0.1, 80:20 to 99.9:0.1, 85:15 to 99.9:0.1, 90:10 to 99.9:0.1, 95:5 to 99.9:0.1, 97:3 to 99.9:0.1, 95:5 to 99:1, or 97:3 to 99:1. The high-pressure low-density polyethylene and masterbatch may also be reacted such that the amount of masterbatch in the high-pressure low-density polyethylene is in the range of 0.1 to 40% by weight. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the high-pressure low-density polyethylene and masterbatch may be reacted such that the amount of masterbatch in the first polyethylene resin is in the range of 0.1 to 35% by weight, 0.1 to 30% by weight, 0.1 to 25% by weight, 0.1 to 20% by weight, 0.1 to 15% by weight, 0.1 to 10% by weight, 0.1 to 5% by weight, 0.1 to 3% by weight, 1 to 5% by weight, or 1 to 3% by weight.

[0046] The high-pressure low-density polyethylene and masterbatch are subjected to a temperature above the polymer's softening point for a sufficient amount of time to allow the reaction between the high-pressure low-density polyethylene and the free radical generator to take place. In some embodiments, the high-pressure low-density polyethylene and masterbatch are subjected to a temperature of 280°C or less. All individual values ​​and subranges of 280°C or less are included and disclosed herein. For example, the temperature may be 280, 260, 250, 240, 220, 200, 180, or 160°C or less. In some embodiments, the temperature is 120°C to 280°C, 140°C to 280°C, 160°C to 280°C, 180°C to 280°C, or 180°C to 260°C. In alternative embodiments, the temperature is 200°C to 260°C. It will be understood that the time required for the reaction may vary depending on the temperature, the amount of material being reacted, and the type of apparatus used. Under exemplary conditions, the time for which the temperature above the polymer's softening point is maintained may range from 10 seconds to 30 minutes. All individual values ​​and subranges are incorporated into and disclosed herein. For example, the time may range from a lower limit of 10 seconds, 20 seconds, 30 seconds, 1 minute, 5 minutes, 15 minutes, or 25 minutes to an upper limit of 45 seconds, 3 minutes, 8 minutes, 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, 23 minutes, or 30 minutes. For example, the time may range from 10 seconds to 20 minutes, or alternatively, the time may range from 10 seconds to 15 minutes, or alternatively, the time may range from 10 seconds to 10 minutes, or alternatively, the time may range from 20 seconds to 20 minutes, or alternatively, the time may range from 15 minutes to 30 minutes.

[0047] In the embodiment, the method is (a) 0.916 g / cm³ 3 ~0.940g / cm 3(b) To provide high-pressure low-density polyethylene (as described above) having a density in the range of , a melt index (I2) in the range of 2.0 to 30.0 g / 10 min, and less than 0.20 vinyl groups per 1,000 total carbon atoms; and (b) To provide a masterbatch composition (as described above) comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density of 0.900 g / cm³ 3 ~0.970g / cm 3 (c) providing a polyethylene composition having a density in the range of 0.01 g / 10 min to a melt index in the range of 0.01 g / 10 min to 100 g / 10 min, (d) reacting high-pressure low-density polyethylene with a masterbatch composition to form a polyethylene composition, and (d) extruding the polyethylene composition as a coating layer onto a substrate layer including a substrate to form a multilayer structure, wherein during the extruding coating of the polyethylene composition as a coating layer, the coating layer is formed to have a neck-in of less than 4.00 inches at 440 feet / min, or alternatively less than 3.50 inches, or alternatively less than 3.00 inches, or alternatively less than 2.50 inches.

[0048] In the embodiment, the method is (a) 0.916 g / cm³ 3 ~0.940g / cm 3 (b) To provide high-pressure low-density polyethylene (as described above) having a density in the range of , a melt index (I2) in the range of 2.0 to 30.0 g / 10 min, and less than 0.20 vinyl groups per 1,000 total carbon atoms; and (b) To provide a masterbatch composition (as described above) comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density of 0.900 g / cm³ 3 ~0.970g / cm 3(c) providing a polyethylene composition having a density in the range of 0.01 g / 10 min to a melt index in the range of 0.01 g / 10 min to 100 g / 10 min, (d) reacting high-pressure low-density polyethylene with a masterbatch composition to form a polyethylene composition, and (d) extruding the polyethylene composition as a coating layer onto a substrate layer including a substrate to form a multilayer structure, wherein during the extruding coating of the polyethylene composition as a coating layer, the coating layer is formed to have a neck-in of less than 3.50 inches at 880 feet / min, or alternatively less than 3.00 inches, or alternatively less than 2.50 inches.

[0049] Goods The multilayer structure of the present invention can be used to form articles such as packaging. Such articles can be formed from any of the multilayer structures described herein.

[0050] Examples of articles that can be formed from the multilayer structures of the present invention include flexible packaging, pouches, self-standing pouches, and ready-made packaging or pouches. In some embodiments, the multilayer structures or articles of the present invention can be used for industrial packaging. Such articles can be formed using techniques known to those skilled in the art, based on the teachings herein and on specific uses of the packaging.

[0051] Test method Unless otherwise specified herein, the following analytical methods are used in describing aspects of the present invention.

[0052] density Density is measured according to ASTM D792, in grams per cubic centimeter (g / cm³). 3 It is represented as follows: Melt Index (I2)

[0053] The melt index, or I2, is measured at 190°C and 2.16 kg according to ASTM D1238.

[0054] Vinyl unsaturated The sample was prepared by adding approximately 130 mg of the sample to 3.25 g of 50 / 50 tetrachloroethane-d2 / perchloroethylene by weight in a 10 mm Norell 1001-7 NMR tube, along with 0.001 M Cr(AcAc)3. The sample was purged by passing nitrogen through the solvent via a pipette inserted into the tube for approximately 5 minutes, then the tube was capped, sealed with Teflon tape, and immersed overnight at room temperature to facilitate dissolution. The sample was heated to 115°C and vortexed to ensure homogeneity.

[0055] 1 ¹H NMR was performed on a Bruker AVANCE 400MHz spectrometer equipped with a Bruker Dual DUL high-temperature CryoProbe, at a sample temperature of 120°C. Two experiments were performed to obtain spectra: a control spectrum for quantifying total polymer protons and a double pre-saturation experiment. This experiment suppressed strong polymer backbone peaks, enabling a highly sensitive spectrum for quantifying end groups. The control spectrum was performed with a ZG pulse, 4 scans, AQ 1.64 seconds, and D1 (relaxation delay) 14 seconds. The double pre-saturation experiment was performed with a modified pulse sequence, 100 scans, DS 4, AQ 1.64 seconds, D1 (pre-saturation time) 1 second, and D13 (relaxation delay) 13 seconds. The vinyl content was determined by integrating the region from 4.95 to 5.15 ppm.

[0056] Half-life C 20 H 42 The thermal decomposition of different free radical generators (FRGs) as 10(w / w)% solutions in (eicosane) was investigated under both isothermal and temperature scanning conditions using a SensysEvo DSC instrument (Setaram, France). To obtain the rate law (kinetic parameters) for the thermal decomposition of FRGs, C 20 H 42A 10(w / w)% solution of FRG in eicosane was measured in temperature scanning mode at five different scanning speeds: 1°C / min, 2.5°C / min, 5°C / min, 10°C / min, and 20°C / min, over a temperature interval of 75°C to 350°C. Approximately 60 mg of the sample (10(w / w)%) of FRG in eicosane was loaded into a 170 mL aluminum pan and placed in a DSC instrument under a nitrogen atmosphere (20 cc / min) at 75°C (above the melting point of paraffin). After thermal equilibrium, the temperature was scanned according to the temperature program described above, and a thermogram was recorded. Exothermic peaks were recorded at temperature intervals of 120°C to 320°C. The amount of heat released, -ΔHr (J / g), was determined from the DSC curve of each specimen, which allows for the calculation of reaction progress / conversion with temperature. The kinetic parameters describing the decomposition rate were determined by both the equiconversion method (using AKTS Thermokinetic software, AKTS AG, Switzerland) and the best parameters following the Sestak-Berggren autocatalytic model. Activation energy, E a (kJ / mol), and the apparent frequency factor as a function of the decomposition process, α, lnA(α)·f(α)(s -1 (-) is determined using Friedman's differential and integral transformation methods and Ozawa's integral transformation method. The general form of the Sestak-Berggren equation is given below:

number

[0057] Decomposition energy and peak decomposition temperature The decomposition energy and peak decomposition temperature were measured using differential scanning calorimetry (DSC). This analysis was performed using a TA Instruments Q2000 DSC equipped with an RCS (refrigerated cooling system). 0.5–2 mg of sample was placed in a glass capillary tube, weighed, and flame-sealed under nitrogen while maintaining cooling using a "cold finger" device. The analysis was then performed to determine its thermal properties.

[0058] The thermal behavior of the sample was determined by increasing the sample temperature and creating a heat-flux-temperature profile. First, the sample was heated from 0°C to 400°C at a rate of 10°C / min. Next, the sample was cooled. Then, the sample was heated again at a heating rate of 10°C / min (this is a “reheating” increase). Both heating curves were recorded. The initial thermal curve was analyzed by setting baseline points from the start to the end of thermal activity. Reheating was used to help determine the start and end of integration.

[0059] For free radical generators, the peak temperature and total decomposition energy were recorded by integrating the area between the curve of the first thermal cycle and the baseline. If the decomposition is exothermic, the area between the curve and the baseline is integrated as negative due to the fact that there is a negative heat flow; that is, the sample generates heat. If the sample is endothermic and absorbs heat, the area is integrated as a positive number.

[0060] The heat below the exothermic peak was estimated by dividing by purity and extrapolating to 100% pure radical generator.

[0061] High-temperature gel permeation chromatography (HT-GPC) A high-temperature gel permeation chromatography system from PolymerChar (Valencia, Spain), consisting of an infrared concentration detector (IR-5), is used to determine the minimum molecular weight (MW) and minimum molecular weight (MWD). The solvent delivery pump, online solvent degassing device, automated sampler, and column oven are manufactured by Agilent. The column and detector compartments operate at 150°C. The column is a three-PLgel 10 μm mixed-B column (Agilent). The carrier solvent is 1,2,4-trichlorobenzene (TCB) with a flow rate of 1.0 mL / min. Both the chromatography and sample preparation solvent sources contain 250 ppm butylated hydroxytoluene (hydroxytoluene, BHT) and are nitrogen-spurged. The polyethylene sample is prepared at a target polymer concentration of 2 mg / mL by dissolving it in TCB at 160°C for 3 hours in the automated sampler immediately before injection. The injection volume is 200 μL.

[0062] Calibration of the GPC column set is performed using 21 narrow molecular weight distribution polystyrene standards. The molecular weights of the standards range from 580 to 8,400,000 g / mol, with at least 10 differences between individual molecular weights, and are arranged in six "cocktail" mixtures. The peak molecular weights of the polystyrene standards are converted to polyethylene molecular weights using the following formula (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)).

number

[0063] In the equation, B has a value of 1.0, and the experimentally determined value of A is approximately 0.42.

[0064] A cubic polynomial is used to fit each polyethylene equivalent calibration point obtained from equation (1) to their observed elution volumes. The actual polynomial fit is obtained by relating the logarithm of the polyethylene equivalent molecular weight to the observed elution volume (and associated force) for each polystyrene standard.

[0065] The number-average, weight-average, and z-average molecular weights are calculated according to the following formulas.

number

number

number

[0066] The precise A value was determined by adjusting the A value in equation (1) until the weight-average molecular weight and the corresponding retention capacity polynomial, calculated using equation (3), matched the independently determined value of Mw obtained according to a linear homopolymer reference with a known weight-average molecular weight of 120,000 g / mol.

[0067] Neck-in Neck-in is measured and reported as the difference between the web width at the die exit and the width of the coating layer after formation on the coated substrate. The width reduction is neck-in and is reported in inches.

[0068] drawdown Drawdown is reported as the rate at which the web can be stretched before it breaks. To measure drawdown, the line velocity is increased until the web breaks, and the velocity at the point of breakage is reported as drawdown in feet per minute (fpm). [Examples]

[0069] The following examples illustrate the features of the present disclosure, but are not intended to limit the scope of the present disclosure. The following materials are used in the examples.

[0070] [Table 1] *All resins listed in Table 1 are commercially available from The Dow Chemical Company (Midland, MI). **Not measured=NM

[0071] In addition to the high-pressure low-density polyethylene and linear low-density polyethylene polymers listed in Table 1, the masterbatch composition DOWLEX® GM AX01 is used. DOWLEX® GM AX01 is commercially available from The Dow Chemical Company (Midland, MI). DOWLEX® GM AX01 contains a free radical generator (cyclic peroxide) and a polyethylene resin. The free radical generator has a half-life of 82 seconds at 220°C, a decomposition energy of -835 (kJ / mol), a molecular weight of 264.3 daltons, and a peak decomposition temperature of 208°C. The polyethylene resin in the masterbatch composition is 0.920 g / cm³ 3 It has a density and a melt index (I2) of 16 g / 10 min. The free radical generator is added in an amount of 1,000 ppm relative to the total amount of polyethylene resin to form the masterbatch composition.

[0072] Extrusion coating blend studies were conducted to confirm neck-in reduction by blending the high-pressure low-density polyethylene or linear low-density polymers listed in Table 1 with the masterbatch composition DOWLEX® GM AX01 ("MB") and coating this blend onto 50 lb multilayer brown kraft paper (a substrate layer including the substrate). Examples of the present invention and comparative examples are provided in Table 2 below, each containing specific amounts of LDPE and MB blended and extruded onto 50 lb multilayer brown kraft paper.

[0073] The extrusion coating trials are performed using a Black-Clawson line following conventional coating procedures. Single-layer coatings are extruded using a 3-layer EC line, with only a primary 3.5-inch diameter extruder (30:1 L / D) equipped with a 150 HP Eurotherm drive. The primary barrel consists of six heater zones with temperature profiles A1-16 = 180 / 230 / 285 / 315 / 315 / 315°C. A 36-inch Nordson 36-inch Autoflex VI LH40 EPC die with internal deckle edge bead reduction is used, with a die gap of 0.5-0.6 mm (0.020 inch) and an air gap of 153 mm (6 inch). The line is equipped with a 30-inch chill roll, nip roll, backing roll, and shear slitter. Extrusion coating is performed at 600°C (or 315°C) at 25 gsm, a screw speed of 90 RPM and 250 lbs / hour, with a die width of 24 inches and a die gap of 20 mils, resulting in a 1 mil coating thickness at 440 ft / min on 50 lb multilayer brown kraft paper.

[0074] [Table 2]

[0075] During the extrusion coating of the coating layer (i.e., a blend of LLDPE or LDPE and MB) onto the substrate layer (kraft paper), the neck-in and draw-down of the coating layer are measured according to the test method described above. Table 3 below provides the results.

[0076] [Table 3] *Maximum line speed for measuring drawdown.

[0077] As shown in Table 3, Comparative Examples 1-4 represent five different high-pressure low-density polyethylenes commonly used in extrusion coatings. When the MB composition is added (Examples 1-8 of the present invention) and the blend is extruded onto a substrate, neck-in is reduced and drawdown is maintained or improved. Comparative Examples 5 and 6 include LLDPE, and adding the MB composition to the LLDPE did not improve neck-in during processing.

Claims

1. A multilayer structure, (a) A substrate layer including a substrate, (b) A coating layer comprising a polyethylene composition, wherein the polyethylene composition is (i) 0.916g / cm ３ ~0.940g / cm ３ Density in the range of 2.0 to 30.0 g / 10 min, melt index (I ２ ), and high-pressure low-density polyethylene having less than 0.20 vinyl groups per 1,000 total carbon atoms, and (ii) A masterbatch composition comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density in the range of 0.900 g / cm³ to 0.970 g / cm³ and a melt index in the range of 0.01 g / 10 min to 100 g / 10 min, comprising a coating layer, The substrate layer is coated with the coating layer, A multilayer structure comprising the polyethylene composition comprising 90 to 99.5% by weight of the high-pressure low-density polyethylene and 0.5 to 10% by weight of the masterbatch composition.

2. The multilayer structure according to claim 1, wherein the high-pressure low-density polyethylene and 0.5 to 10% by weight of the masterbatch composition are reacted in a ratio of 60:40 to 99.9:0.

1.

3. The multilayer structure according to claim 1 or 2, wherein the amount of the free radical generating agent is less than 100 ppm relative to the total amount of the polyethylene resin.

4. The multilayer structure according to any one of claims 1 to 3, wherein the free radical generating agent has a half-life of 60 to 120 seconds at 220°C.

5. The multilayer structure according to any one of claims 1 to 4, wherein the molecular weight of the free radical generator is 200 to 1,000 daltons.

6. The multilayer structure according to any one of claims 1 to 5, wherein the free radical generating agent is a cyclic peroxide.

7. The multilayer structure according to any one of claims 1 to 6, wherein the substrate of the substrate layer comprises at least one of film, nonwoven fabric, woven fabric, scrim, foil, carpet, plastic, saran, paper, cellulose, or metal.

8. A method for forming a multilayer structure, (a) 0.916g / cm ３ ~0.940g / cm ３ Density in the range of 2.0 to 30.0 g / 10 min, melt index (I ２ To provide high-pressure, low-density polyethylene having less than 0.20 vinyl groups per 1,000 total carbon atoms, (b) To provide a masterbatch composition comprising a free radical generator and a polyethylene resin, wherein the free radical generator has a half-life of less than 200 seconds at 220°C and a decomposition energy higher than -250 kJ / mol, and the polyethylene resin has a density in the range of 0.900 g / cm³ to 0.970 g / cm³ and a melt index in the range of 0.01 g / 10 min to 100 g / 10 min, (c) Reacting the high-pressure low-density polyethylene with the masterbatch composition to form a polyethylene composition, (d) The polyethylene composition is extruded onto a substrate layer containing a base material to form the multilayer structure, A method wherein the polyethylene composition comprises 90 to 99.5% by weight of the high-pressure low-density polyethylene and 0.5 to 10% by weight of the masterbatch composition.

9. The method according to claim 8, wherein, during the extrusion coating of the polyethylene composition as the coating layer, the coating layer has a neck-in of less than 4.00 inches at 440 feet / min.

10. The method according to claim 8 or 9, wherein, during the extrusion coating of the polyethylene composition as the coating layer, the coating layer has a neck-in of less than 3.50 inches at 880 feet / min.

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