Metallized polyethylene film and related structures

Abstract

Disclosed herein is a film comprising at least one layer comprising polyethylene and a metal layer, the film having less than 300 parts per million (ppm) of metal stearate and less than 50 ppm of stearic acid, based on the total weight of the film. Also disclosed herein is such a film comprising at least one layer comprising polyethylene and a metal layer, the metal layer having a modulus of at least 38 dynes / cm one week after metallization. Also disclosed herein is an article comprising such a film laminated to a substrate.

Description

[Technical Field]

[0001] This disclosure relates to metallized polyethylene films for packaging applications. [Background technology]

[0002] In some applications, packaging films must exhibit excellent barrier properties against moisture and / or oxygen to protect the contents of the package. While plastic packaging materials offer toughness, lightness, and design flexibility that glass and metal cannot match, most plastics, especially polyolefins, are permeable to oxygen and water vapor and are therefore unsuitable as packaging films on their own. One approach to improving the barrier properties of polyolefin-based film structures has been to provide a thin metallized layer on the surface of the film. The thin metallized layer provides the film with significantly enhanced barrier properties against oxygen and water vapor and contributes to the primary resistance to mass transfer during permeation.

[0003] Metallization can be carried out in various ways, among which vapor deposition is well-established and commercially available. In this process, a metal (such as Al or Cu) evaporates through a heated boat in a vacuum chamber and deposits onto the surface of a substrate such as a plastic film. Commonly used polymer films include biaxially oriented polyethylene terephthalate (BOPET), biaxially oriented polypropylene (BOPP), and cast polypropylene (CPP). For example, a metallized film can be laminated with a printed polyethylene terephthalate (PET) film on the outside and a polyethylene sealant film on the inside. [Overview of the project] [Problems that the invention aims to solve]

[0004] Metallized films require good adhesion to the metallized surface in certain applications. For example, the metallized surface of a metallized film may be printed on or laminated to other layers. However, adhesion to metallized polyethylene films has been a problem that limits the use of such films in the market. Therefore, there remains a need for metallized polyethylene packaging films that exhibit good adhesion of other materials to the metallized surface.

[0005] This disclosure reflects the finding that metal stearate and / or its by-product, stearic acid, is responsible for the poor adhesion of metallized polyethylene films to metallized surfaces. Metal stearate (typically calcium stearate or zinc stearate) is commonly used as a neutralizing agent in the production of polyethylene using the Ziegler-Natta catalyst, including many commercially available LLDPE and HDPE materials. In particular, these stearate and / or stearic acid molecules have been found to migrate rapidly to the surface, significantly lowering the surface energy of the metallized surface. This is particularly problematic because, since the metallized films are wound on rolls, migration to either surface can contaminate the metal surface.

[0006] Accordingly, disclosed herein is a film comprising at least one layer containing polyethylene and a metal layer, wherein the film has no more than 300 parts per million by weight (ppm) of metal stearate and no more than 50 ppm of stearic acid, based on the total weight of the film. Also disclosed herein is such a film comprising at least one layer containing polyethylene and a metal layer having at least 38 dynes / cm after one week of metallization. Furthermore, disclosed herein is an article comprising such a film laminated on a substrate. [Modes for carrying out the invention]

[0007] Disclosed herein are films comprising at least one polyethylene-containing layer and a metal layer, and articles such as laminates or packaging comprising such films. These layers may be bonded and in contact with each other.

[0008] Polyethylene-containing film layer The films disclosed herein have at least one layer containing polyethylene. One layer containing polyethylene may be provided. Alternatively, two or more layers containing polyethylene may be provided. These layers may be bonded and in contact. Three (or more) layers containing polyethylene may be provided. If three (or more) layers containing polyethylene are provided, the layer adjacent to the metal layer is referred to herein as the first layer, the layer on the outer side of the film opposite the metal layer is referred to as the sealant layer, and one or more layers between the first layer and the sealant layer are one or more core layers. If only one layer containing polyethylene is provided, any of the polyethylene compositions described herein as the first layer, core layer, or sealant layer may be used. If only two layers containing polyethylene are provided, any combination of the first layer and the core layer, the first layer and the sealant layer, or the core layer and the sealant layer may be used. When two or more polyethylene-containing layers are provided, each polyethylene-containing layer may be directly adjacent to at least one other polyethylene-containing layer, or an adhesive layer or other intermediate layer may be used between the two or more polyethylene-containing layers.

[0009] Each film and each layer containing polyethylene within the film may be characterized by being free of (0 ppm) or substantially free of metal stearate (e.g., calcium stearate or zinc stearate) and stearic acid. Specifically, the amount of metal stearate (e.g., calcium stearate or zinc stearate) in the film may be 300 ppm or less, 250 ppm or less, 200 ppm or less, 100 ppm or less, or 50 ppm or less, based on the total weight of the film. The amount of metal stearate (e.g., calcium stearate or zinc stearate) in the polyethylene layer within the film may be 300 ppm or less, 250 ppm or less, 200 ppm or less, 100 ppm or less, or 50 ppm or less, based on the weight of the polyethylene layer. The inventors have found that the amount of metal stearate can be acceptable at amounts lower than the above limitations. Therefore, the polyethylene layer may contain 0.01 ppm or more, 0.1 ppm or more, or 1 ppm or more of metal stearate (e.g., calcium stearate or zinc stearate) based on the total weight of the layer. Similarly, the film may contain 0.01 ppm or more, 0.1 ppm or more, or 1 ppm or more of metal stearate (e.g., calcium stearate or zinc stearate) based on the total weight of the film. Such amounts do not cause substantial degradation of the surface energy of the metal layer for a maximum of 1, 2, 3, or 4 weeks after metallization. The amount of stearic acid in the film may be 50 ppm or less, 40 ppm or less, or 30 ppm or less, based on the total weight of the film. The amount of stearic acid in the polyethylene layer of the film may be 50 ppm or less, 40 ppm or less, or 30 ppm or less, based on the total weight of the polyethylene layer. The inventors have found that small amounts of stearic acid are acceptable. Therefore, stearic acid may be found in the polyethylene layer in amounts of 0.01 ppm or more, 0.1 ppm or more, or 1 ppm or more, based on the total weight of the layer. Similarly, metal stearate (e.g., calcium stearate or zinc stearate) may be found in the film in amounts of 0.01 ppm or more, 0.1 ppm or more, or 1 ppm or more, based on the total weight of the film.

[0010] While stearates should be avoided, the layer may contain small amounts (e.g., less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 500 ppm, or less than 400 ppm, based on the total weight of the layer) of non-stearic acid catalyst neutralizers, such as hydrotalcite (e.g., DHT4V / DHT4A from Kisuma).

[0011] The first layer may contain polyethylene. The polyethylene in the first layer may be linear low-density polyethylene (LLDPE). This LLDPE may be single-site catalyzed polyethylene (such as m-LLDPE, but not limited to this). The first layer may further contain one or more additional polyethylenes, such as low-density polyethylene (LDPE). The additional polyethylene may be present in amounts from 0 weight percent, 1 weight percent, 5 weight percent, or 10 weight percent, up to about 40 weight percent, up to 30 weight percent, or up to 20 weight percent, based on the total weight of the first layer. The first layer may further contain additives such as antioxidants, UV stabilizers, heat stabilizers, lubricants, anti-blocking agents, pigments or colorants, processing aids, crosslinking catalysts, flame retardants, fillers, and foaming agents. When used in combination with a second polyethylene-containing layer, such as a core layer or sealant layer, the first layer is a metallized layer that, in that case, is advantageously free of lubricants but may contain antiblocking agents (e.g., talc, silicon dioxide, etc.), antioxidants, and processing aids (e.g., PEA-3S from AVI Polymers). For example, the antiblocking agent may be present in the first layer in an amount of at least 1000 ppm or 1500 ppm to 5000 ppm. The total amount of additives may be less than 10 weight percent or less than 5 weight percent based on the total weight of the first layer.

[0012] The polyethylene-containing layer may include medium-density polyethylene (MDPE), high-density polyethylene (HDPE), or a combination thereof. This layer may be a core layer. This layer may further contain one or more additional polyethylenes (such as LDPE) in amounts ranging from 0% by weight, 1% by weight, or 5% by weight, up to 40% by weight, up to 30% by weight, or up to 20% by weight, based on the total weight of the layer. This configuration may be particularly useful as a core layer. This layer may also contain the additives described for the first layer, in the amounts described for the first layer, particularly antioxidants. The total amount of additives may be less than 10% by weight or less than 5% by weight, based on the total weight of this layer.

[0013] When used as an inner or core layer, additives such as lubricants or anti-blocking agents are not typically used. This layer can be adjacent to the first layer, on the opposite side of the metal layer in the first layer.

[0014] Layers containing medium-density polyethylene (MDPE), high-density polyethylene (HDPE), or a combination thereof may have a tensile modulus of at least 200 MPa, at least 250 MPa, at least 300 MPa, at least 350 MPa, or at least 400 MPa in the mechanical direction, as measured with a tensile machine (Type 5943, INSTRON, etc.) conforming to ASTM D882.

[0015] The polyethylene-containing layer may include linear low-density polyethylene (LLDPE). The LLDPE may be single-site catalyzed polyethylene (such as mLLDPE). This layer may further contain one or more additional polyethylenes, such as low-density polyethylene (LDPE). The additional polyethylene may be present in amounts from 0% by weight, 1% by weight, 5% by weight, or 10% by weight, up to about 40% by weight, up to 30% by weight, or up to 20% by weight, based on the total weight of this layer. This layer may also contain additives in the amounts described for the first layer, as described for the first layer. This may be the outer layer of the film. This layer may be a sealant layer. In its use as an outer layer or sealant layer, the layer may, advantageously in certain embodiments, contain an antiblocking agent. For example, in certain embodiments, the antiblocking agent may be present in amounts from at least 1000 ppm, or at least 1500 ppm, up to 5000 ppm. Furthermore, in its use, an anti-slip agent (e.g., erucamide) may be useful. For example, anti-slip agents may be present in amounts ranging from 100 ppm or 200 ppm to 1000 ppm or 800 ppm. The total amount of additives may be less than 10 weight percent or less than 5 weight percent, based on the total weight of this layer (e.g., outer layer or sealant layer).

[0016] Polyethylene films can be cast films or extruded films. Films can be oriented. Films can be blown films (which may contribute to orientation). Films can be uniaxially oriented. Films can be biaxially oriented. Films can be co-extruded, for example, co-extruded blown-oriented films. Films can be treated on the surface to be metallized. Examples of treatments include flame treatment, corona treatment, and plasma treatment. For example, a blown film may be corona-treated on the outer layer and then split using a side slitter. The surface energy of the film on the surface to be metallized before metallization may be at least 42 dynes / cm or at least 46 dynes / cm.

[0017] The film before metallization may have a mechanical directional tensile modulus of at least 300 or at least 350 MPa, as measured by a tensile machine conforming to ASTM D882 (e.g., Type 5943, INSTRON). The stiffer the film, the easier it is to metallize.

[0018] Metallization and metallized films Polyethylene films can be metallized by any known method for metallizing polyethylene films. For example, a metal layer can be applied using vacuum metallization. This may involve providing a metal source and evaporating it in a vacuum environment to condense it on the surface of the film.

[0019] Suitable metals include Al, Zn, Au, Ag, Cu, Ni, Cr, Ge, Se, Ti, Sn, or their oxides. The metal layer can be formed from aluminum or aluminum oxide (Al2O3).

[0020] The thickness of the metal layer according to a particular embodiment can be at least 10 nanometers, at least 20 nanometers, or at least 30 nanometers, and can be 100 nanometers or less, 90 nanometers or less, 80 nanometers or less, 70 nanometers or less, or 60 nanometers or less.

[0021] After metallization, the metallized film can be stored in a roll, which is convenient. In this process, the metallized surface layer is in contact with the polyethylene layer on the opposite side of the film. The film can be stored at a temperature in the range of 20 to 25 °C and a relative humidity of 10 to 20%.

[0022] The overall thickness of the metallized film can be at least 10 microns, at least 20 microns, or at least 30 microns. The overall thickness of the metallized film according to a particular embodiment is 100 microns or less, 80 microns or less, 60 microns or less, or 40 microns or less.

[0023] The metallized film can have an optical density (OD) of at least 2, at least 2.1, at least 2.2, or at least 2.3, and 2.7 or less, 2.6 or less, or 2.5 or less. In some embodiments, the OD is 2.4. The optical density of the metallized film (e.g., a multilayer structure comprising a polyethylene film with a metal layer deposited thereon) can be measured using an optical densitometer (model number LS177 manufactured by Shenzhen Linshang Technology).

[0024] The metallized film can retain a surface energy of at least 1 week or at least 2 weeks after metallization, at least 38 dynes / cm, at least 40 dynes / cm, or at least 42 dynes / cm of the metallized surface.

[0025] The metallized film as described above can be printed and / or laminated onto a substrate such as another film. This other film can be another polymeric material such as polyester (e.g., polyethylene terephthalate, i.e., PET). The excellent retention of surface energy of the present metallized film avoids the problems previously seen with lamination or printing onto metallized polyethylene.

[0026] The metallized film (with or without lamination to another film) can be used to form articles such as packaging. Examples of packaging that can be formed from the multilayer structure of the present invention can include flexible packaging, pouches, stand-up pouches, and pre-made packages or pouches. The multilayer film of the present invention can be used for food packages. Examples of foods that can be included in such packaging include meat, cheese, cereal, nuts, juice, sauce, etc. Such packaging can be formed using techniques known to those skilled in the art based on the teachings of this specification and based on the particular use of the packaging (e.g., type of food, amount of food, etc.).

[0027] Test Methods and Definitions Unless otherwise stated, not implied from the context, or not conventional in the art, all parts and percentages are by weight, all temperatures are in °C, and all test methods are the latest at the time of filing of the present disclosure.

[0028] As used herein, the term "composition" refers to a mixture of materials including the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0029] "Polymer" means a polymer compound prepared by polymerizing monomers, whether of the same or different types. Thus, the general term polymer encompasses the term homopolymer (used to refer to a polymer prepared from only one type of monomer, under the understanding that trace amounts of impurities may be incorporated into the polymer structure) and the term interpolymer, as defined herein below. Trace amounts of impurities (e.g., catalyst residues) may be incorporated into and / or within the polymer. A polymer can be a single polymer, a polymer blend, or a polymer mixture containing a mixture of polymers formed in situ during polymerization.

[0030] As used herein, the term “interpolymer” refers to a polymer prepared by the polymerization of at least two different types of monomers. Thus, the collective term “interpolymer” includes copolymers (used to refer to polymers prepared from two different types of monomers) and polymers prepared from three or more different types of monomers.

[0031] The term "adherent contact" and similar terms mean that one surface of one layer and one surface of another layer are in contact and bonded to each other in such a way that one layer cannot be removed from the other layer without damaging the interlayer surfaces (i.e., contacting surfaces) of both layers.

[0032] The terms “comprising,” “including,” and “having,” and their derivatives, are not intended to exclude the existence of any additional components, steps, 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 “essentially consisting of” excludes any other components, steps, or procedures from the scope of any subsequent description, except those not essential to operability. The term “consisting of” excludes any components, steps, or procedures not specifically specified or enumerated.

[0033] "Polyethylene" or "ethylene-based polymer" means a polymer containing units derived from a majority (>50 mol%) of ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of polyethylene known in the art include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (ULDPE), extremely low-density polyethylene (VLDPE), single-site catalyst linear low-density polyethylene (m-LLDPE), which includes both linear and substantially linear low-density resins, medium-density polyethylene (MDPE), and high-density polyethylene (HDPE). While these polyethylene materials are generally known in the art, the following description may be helpful in understanding some of the differences among these different polyethylene resins.

[0034] The term "LDPE" may also be referred to as "high-pressure ethylene polymer" or "highly branched polyethylene," and is defined to mean that the polymer is partially or completely homopolymerized or copolymerized in an autoclave or tubular reactor at a pressure exceeding 14,500 psi (100 MPa) using a free radical initiator such as a peroxide (see, for example, US4,599,392 incorporated by reference). LDPE resins typically have a viscosity of 0.916–0.935 g / cm³. 3 It has a density within the range.

[0035] The term "LLDPE" includes both resins produced using single-site catalysts, including but not limited to traditional Ziegler-Natta catalyst systems and chromium-based catalysts, as well as bis-metallocene catalysts (sometimes referred to as "m-LLDPE") and constrained geometric catalysts, and includes linear, substantially linear, or heterogeneous polyethylene copolymers or homopolymers. LLDPEs contain fewer long-chain branches than LDPEs and include substantially linear ethylene polymers as further defined in U.S. Patents 5,272,236, 5,278,272, 5,582,923, and 5,733,155; homogeneously branched linear ethylene polymer compositions such as those described in U.S. Patent 3,645,992; heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent 4,076,698; and / or blends thereof (e.g., those disclosed in U.S. 3,914,342 or U.S. 5,854,045). LLDPEs can be produced by gas-phase, liquid-phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0036] The term "MDPE" refers to 0.926-0.935 g / cm³ 3This refers to polyethylene having a density of . "MDPE" is typically produced using chromium or Ziegler-Natta catalysts, or single-site catalysts including but not limited to bis-metallocene catalysts and constrained geometric catalysts, and typically has a molecular weight distribution ("MWD") greater than 2.5.

[0037] The term "HDPE" generally refers to single-site catalysts, including but not limited to Ziegler-Natta catalysts, chromium catalysts, or bis-metallocene catalysts and constrained geometry catalysts, prepared at approximately 0.935 g / cm³. 3 Super ~ approx. 0.970g / cm 3 This refers to polyethylene having a certain density.

[0038] The term "ULDPE" generally refers to single-site catalysts, including but not limited to Ziegler-Natta catalysts, chromium catalysts, or bis-metallocene catalysts and constrained geometry catalysts, prepared at concentrations of 0.880–0.912 g / cm³. 3 This refers to polyethylene having a certain density.

[0039] Generally, compositions, methods, and articles may, by substitution, consist of, or essentially consist of any material, step, or component disclosed herein. Compositions, methods, and articles may, additionally or by substitution, be formulated, implemented, or manufactured without, or substantially without, any material, step, or component not necessary to achieve the function or purpose of the claims herein. Films and articles disclosed herein include combinations of embodiments described herein.

[0040] All ranges disclosed herein include endpoints, and these endpoints can be combined independently of each other (for example, “up to 25% by weight, more specifically, 5% to 20% by weight” includes the endpoints and all intermediate values ​​of the range “5% to 25% by weight”, etc.). Furthermore, the upper and lower limits described can be combined to form ranges (for example, “at least 1 or at least 2% by weight” and “up to 10 or 5% by weight” can be combined as the ranges “1 to 10% by weight”, or “1 to 5% by weight”, or “2 to 10% by weight”, or “2 to 5% by weight”). [Examples]

[0041] The surface energy of the film and metallized film is monitored over time in accordance with ASTM Std.D2578 by testing the wettability of the test fluid and the wettability of the tested substrate. Examples The materials used are shown in Table 1. [Table 1]

[0042] The films are manufactured on a commercially available 7-ply blow film line equipped with feeders suitable for single-layer or 3-layer blow films. The film width is 400 mm. In-line corona treatment ensures the film's surface energy exceeds 50 dynes / cm. In the single-layer example, the blow film conditions are kept the same, with a thickness of 50 μm and a blow-up rate (BUR) of 2.3. In the 3-layer example, the blow film conditions are kept the same, with a total thickness of 30 μm, a layer ratio of 1:3:1 (outer:core:inner), and a BUR of 2.3. In some examples, additional additives are introduced in addition to those provided as part of the commercially available resin, as listed in Table 2. These additives are mixed into the formulation via pre-formulated LDPE masterbatches. The films are subjected to in-line corona treatment, ensuring the film's surface energy exceeds 50 dynes / cm.

[0043] The film is surface-treated again with an outer layer before metallization, so that the surface energy of the film is higher than 46 dynes / cm before metallization. Metallization of the PE film is performed in a laboratory-scale vacuum deposition chamber (Shenyang Vacuum Technology Institute), where a substrate holder fixes the PE film with the outer layer facing outwards. Al wire (99.9999% purity) is inserted into a container of resistance heater (heating boat). The vacuum level is 3 × 10⁻⁶. -3 When Pa is reached, the heating boat is turned on, and the Al melts and evaporates. The current is adjusted to induce a deposition rate of 40 A / s. A spinning component drives a constant-speed spin of the substrate to facilitate more uniform deposition. A thickness monitor (quartz crystal microbalance (QCM)) is used to monitor the thickness and deposition rate in situ. After ventilating the vacuum deposition chamber, the metallized sample is removed.

[0044] The optical density (OD) of the metallized film is measured using a spectrophotometer under visible light settings. Transmittance (T, %) is used to derive the optical density value.

[0045] Next, the metallized film is stacked inside each PE film, at a density of 0.2 N / cm². 2 The polished glass plate and the washed glass plate are stored under controlled loads at ambient conditions (23°C and 15% RH) to ensure reliable contact between the flexible films.

[0046] At predetermined time intervals, the surface energy of the Al-coated outer surface of each metallized PE film was tested according to ASTM Std. D2578. This value is reported in Table 2, based on the average of five samples.

[0047] The calcium stearate content is determined by analyzing the Ca content using ICP-OES (Inductively Coupled Plasma Atomic Emission Spectrometry). The calcium element is determined by specific wavelengths in the mass spectrum. Standard solutions are prepared within the appropriate concentration range of the calcium element.

[0048] The stearic acid content is analyzed by extracting the additive from the film using CH2Cl2, followed by filtration and analysis by LC-MS (liquid chromatography-mass spectrometry). Standard solutions are prepared within the appropriate concentration range of stearic acid. [Table 2]

[0049] All metallized films had a surface energy exceeding 46 dynes / cm immediately after production (day 0). Comparative Example 1 is a single-layer film made from Dowlex 2045G containing calcium stearate as a catalyst neutralizer. Comparative Example 2 has a high-density PE core layer made of polyethylene using calcium stearate as a catalyst neutralizer in both Elite 5960G and Dowlex 2038.68G. This calcium stearate additive and its stearic acid by-products are thought to form catalyst neutralization and cause the decrease in surface energy. The mobile composition of stearic acid and stearates reaches the metal surface through the low-density inner and outer layers, driving a rapid decrease in surface energy. Comparative Examples 3 and 4 are identical to Example 4 except that the core layer is made of high-density polyethylene only. Examples 1 to 5 show that the surface energy was maintained at an acceptable level for two weeks in the absence of calcium stearate. In particular, Example 5 has DHT4V (a catalyst neutralizer other than calcium stearate) added to the intermediate layer of Example 2. Unless stearate is included in the formulation, the surface energy is retained.

[0050] This disclosure further encompasses the following aspects:

[0051] Appearance 1 A film comprising at least one layer containing polyethylene and a metal layer, wherein the film has, based on the total weight of the film, 300 ppm or less, preferably less than 300 ppm, of metal stearate and 50 ppm or less, preferably less than 50 ppm, of stearic acid.

[0052] Appearance 2 The film according to embodiment 1, wherein the film is a multilayer film, and the first layer contains linear low-density polyethylene.

[0053] Appearance 3 The film according to embodiment 2, wherein the first layer further comprises up to 40 percent by weight of low-density polyethylene.

[0054] Pattern 4 The film according to embodiment 2 or 3, wherein the first layer further comprises one or more of an antioxidant, an antiblocking agent, or a processing aid.

[0055] Appearance 5 A film according to any one of embodiments 2 to 4, further comprising a core layer adjacent to the first layer on the opposite side of the first layer from the metal layer.

[0056] Appearance 6 The core layer has a density of 0.935 to 0.970 g / cm³. 3 The film according to embodiment 5, comprising polyethylene having a combination thereof, and low-density polyethylene of 0 to 40 weight percent.

[0057] Appearance 7 The film according to embodiment 6, wherein the core layer further comprises one or more of an antioxidant and a non-stearic acid catalyst neutralizing agent.

[0058] Appearance 8 The film according to any one of embodiments 2 to 7, further comprising a sealant layer located on the opposite side of the film from the metal layer and on the outer surface of the film.

[0059] Appearance 9 The film according to embodiment 8, wherein the sealant layer comprises linear low-density polyethylene and 0 to 40 weight percent low-density polyethylene.

[0060] Appearance 10 The film according to any one of embodiments 1 to 9, wherein at least one of the layers is surface-treated before metallization to form the metal layer.

[0061] Appearance 11 The film according to any one of embodiments 1 to 10, wherein the at least one layer is a cast film, a co-extruded blow film, or an orientation film (e.g., a uniaxially oriented film or a biaxially oriented film).

[0062] Appearance 12 A film according to any one of embodiments 1 to 11, having a thickness of 10 to 100 microns and an optical density of 2.0 to 2.8.

[0063] Appearance 13 The film according to any one of embodiments 1 to 12, wherein the at least one layer containing polyethylene has a mechanical direction coefficient of at least 300 MPa.

[0064] Appearance 15 A film according to any one of embodiments 1 to 13, having a surface energy of at least 38 dynes / cm on the surface of the metal layer one week after metallization.

[0065] Appearance 16 The film according to embodiment 15, wherein the film is stored in a roll for one week after metallization.

[0066] Appearance 17 The film according to embodiment 15 or 16, wherein the film is stored at a temperature in the range of 20 to 25°C and a relative humidity of 10 to 20%.

[0067] Appearance 18 a. A first layer comprising linear low density polyethylene and up to 40 weight percent of low density polyethylene based on the first layer, optionally further comprising one or more of an antioxidant, an antiblocking agent, or a processing aid; b. A core layer adjacent to the first layer on the side opposite the metal layer in the first layer, the core layer having a density of 0.935 to 0.970 g / cm 3 Or a polyethylene having a combination thereof, and the core layer comprising from 0 to 40 weight percent of low density polyethylene, optionally further comprising one or more of an antioxidant and a non-stearic acid catalyst neutralizer; c. A sealant layer on the side of the film opposite the metal layer, which is the outer surface of the film, the sealant layer comprising linear low density polyethylene and from 0 to 40 weight percent of low density polyethylene, the film according to any one of aspects 1 to 17.

[0068] Aspect 19 The film according to any one of aspects 1 to 18, having printing on the metallized surface.

[0069] Aspect 20 An article comprising the film according to any one of aspects 1 to 19 laminated to a substrate. The present invention includes the following embodiments. Item 1. A film comprising at least one layer containing polyethylene and a metal layer, the film having a metal stearate of 300 ppm or less and stearic acid of 50 ppm or less based on the total weight of the film. Item 2. The film according to item 1, wherein the film is a multilayer film and the first layer contains linear low density polyethylene. Item 3. The film according to item 2, wherein the first layer further contains up to 40 weight percent of low density polyethylene. Item 4. The film according to claim 2 or 3, wherein the first layer further comprises one or more of an antioxidant, an antiblocking agent, or a processing aid. Section 5. The film according to any one of claims 2 to 4, further comprising a core layer adjacent to the first layer on the opposite side of the first layer from the metal layer. Section 6. The core layer has a density of 0.935 to 0.970 g / cm³. 3 The film according to item 5, comprising polyethylene having a combination thereof, and low-density polyethylene from 0 to 40 weight percent. Section 7. The film according to claim 6, wherein the core layer further comprises one or more of an antioxidant and a non-stearic acid catalyst neutralizer. Section 8. The film according to any one of claims 2 to 7, further comprising a sealant layer located on the opposite side of the film from the metal layer and on the outer surface of the film. Section 9. The film according to claim 8, wherein the sealant layer comprises linear low-density polyethylene and 0 to 40 weight percent low-density polyethylene. Section 10. The film according to any one of claims 1 to 9, wherein at least one of the layers is surface-treated before metallization to form the metal layer. Section 11. The film according to any one of claims 1 to 10, wherein the at least one layer is a cast film, a co-extruded blown film, or an oriented film. Section 12. A film according to any one of items 1 to 11, having a thickness of 10 to 100 microns and an optical density of 2.0 to 2.8. Section 13. The film according to any one of claims 1 to 12, wherein the at least one layer containing polyethylene has a mechanical direction coefficient of at least 300 MPa. Section 14. A film according to any one of claims 1 to 13, having a surface energy of at least 38 dynes / cm on the surface of the metal layer one week after metallization. Section 15. An article comprising a film according to any one of items 1 to 14 laminated on a substrate.

Claims

1. A film, wherein the film is A first layer comprising linear low-density polyethylene, the first layer having a metal layer on its surface, A core layer adjacent to the first layer on the opposite side of the first layer from the metal layer, comprising polyethylene having a density of 0.935 to 0.970 g / cm³, low-density polyethylene of 0 to 40 weight percent, and metal stearate of 0 to 250 ppm or less, A sealant layer located on the opposite side of the film from the metal layer and forming the outer surface of the film, comprising a sealant layer containing linear low-density polyethylene and 0 to 40 weight percent low-density polyethylene, A film having 300 ppm or less of metal stearate and 50 ppm or less of stearic acid, based on the total weight of the film.

2. The film according to claim 1, wherein the first layer further comprises up to 40% by weight of low-density polyethylene and / or one or more of an antioxidant, an antiblocking agent, or a processing aid.

3. The film according to claim 1 or 2, having a thickness of 10 to 100 microns and an optical density of 2.0 to 2.

8.

4. The film according to any one of claims 1 to 3, wherein the surface energy of the metal layer is at least 38 dynes / cm one week after metallization.

5. An article comprising a film according to any one of claims 1 to 4 laminated on a substrate.

6. A method for preparing a film according to any one of claims 1 to 4, wherein the first layer is surface-treated before metallization to form the metal layer.

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