Coated film

Abstract

A glossy coated film having recyclable properties, comprising a combination of (a) at least one film layer of a recyclable polyolefin and (b) at least one coating layer, wherein the at least one coating layer comprises an aqueous coating composition and a water-dispersible polyisocyanate, the coating layer having recyclable properties, and the at least one coating layer is disposed on at least a portion of one surface of the at least one film layer of the recyclable polyolefin.

Description

[Technical Field]

[0001] The present invention relates to coated films, and more specifically, to coated films comprising a combination of (a) a polyolefin polymer layer and (b) an aqueous coating layer having beneficial recyclability. [Background technology]

[0002] As plastic production capacity and global consumption continue to increase, the cumulative and irreparable damage to ecosystems caused by plastic waste is widely known and a growing concern. The flexible packaging industry is one of the major sectors, primarily comprised of plastic articles. Therefore, film manufacturers, packaging converters, and brand owners are all urgently seeking ways to reduce, or more ideally eliminate, plastic pollution. Among the approaches to providing sustainable solutions that significantly minimize or eliminate the plastic pollution problem is the development of new recyclable plastic packaging materials. Packaging product converters and manufacturers have already begun planning for 100 percent recyclable or compostable packaging articles for packaging a variety of products.

[0003] Conventional flexible packaging designs typically involve laminating various functional layers composed of different materials such as polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), metallized PET, metallized oriented polypropylene (OPP), aluminum foil, and nylon / polyimide. These functional layers, which provide printable or barrier layers, are generally laminated with sealable layers such as low-density polyethylene (LDPE) or sealable OPP via adhesive layers. Due to the different materials laminated together, the resulting flexible packaging materials are non-recyclable, and an economically practical and technically efficient process for separating the various different films (and layers) and recycling each material individually has yet to be discovered.

[0004] For example, laminating different polyolefin film layers, such as high-density polyethylene (HDPE) and low-density polyethylene (LDPE), biaxially oriented polyethylene (BOPE) and LDPE, BOPP and LDPE, BOPE and BOPP, using conventional adhesives that are either acrylic or polyurethane (PU) based, presents a significant challenge in providing recyclability to the resulting laminated plastic packaging material. Conventional laminating adhesives used to laminate these films are very different from polyolefins in their main chain chemistry and are usually highly crosslinked, thus limiting the feasibility of making this conventional packaging design easily recyclable. To achieve mechanical recyclability of packaging materials, it is preferable and desirable to produce packaging films from a single type of material. However, the material must be heat-sealable to produce packaging articles such as pouches, and generally, sealable polyolefin films, even those made from HDPE, have poor heat-sealing properties, making it almost impossible to directly use a single-type material film to produce packaging materials.

[0005] Conventionally, one method used to produce heat-sealable polyolefin films is to coat the polyolefin film with a solvent-based PU gloss coating made from a polyol component combined with an aromatic polyisocyanate in an organic solvent, such that the coated film is heat-resistant under sealing conditions. For example, International Publication Nos. 2020005927(A1), 2019240921(A1), and 2016196168(A1) disclose coated films and articles formed from such films, wherein the coated film comprises (a) an ethylene-based polymer film and (b) a PU coating, and the coated film is heat-resistant under sealing conditions. However, solvent-based coatings have limitations in terms of recyclability.

[0006] Conventionally, another method used to produce heat-sealable polyolefin films is to coat the polyolefin film with an aqueous coating. For example, U.S. Patent No. 5,188,867(A) discloses a thermoplastic film coated with an aqueous acrylic copolymer combined with a solid material dispersed in the acrylic copolymer. The above patent provides an acrylic coating applied to a polyolefin film, comprising an acrylic emulsion, an inorganic blocking agent, and a wax slip agent. In another example, Canadian Patent No. 2381315(C) discloses a method for producing a high-gloss coating on a printed surface film using an aqueous coating comprising a film-forming coating polymer, additives, and a pigment. While the above known methods provide coated heat-sealable polyolefin films, the known methods use coating formulations with additives containing solid materials such as inorganic pigment particles, and therefore do not provide coated polyolefin films with recyclable properties. [Overview of the Initiative]

[0007] One object of the present invention is to provide a recyclable gloss-coated polyolefin film useful for packaging applications, wherein the coated film has heat-sealing and abrasion-resistant properties, and one side of the polyolefin film has a coating layer made from an aqueous (waterborne, WB) acrylic coating composition formulated using a hydroxyl-functionalized emulsion and additives without containing inorganic pigment particles.

[0008] Another object of the present invention is to provide a heat-sealable coated polyolefin film that can be made from polyolefin material alone and can be used to manufacture articles such as packaging materials for obtaining mechanically recyclable packaging materials. The use of heat-sealable and recyclable polyolefin films is a significant step in helping converters and manufacturers mitigate the problem of plastic pollution.

[0009] According to the present invention, a heat-sealable and recyclable polyolefin film is produced that has heat-sealability on one side of the film and, at the same time, sealability (i.e., heat-sealability) on the other side of the film via a novel heat-seal-resistant coating layer. In one embodiment, the heat-seal-resistant coating layer comprises a novel WB acrylic coating crosslinked with a water-dispersible polyisocyanate. In a preferred embodiment, the WB acrylic coating is formulated from a hydroxyl-functionalized acrylic emulsion and additives, and the WB coating does not contain inorganic pigment particles.

[0010] The heat-sealable coating layer advantageously provides the polyolefin film with high gloss (i.e., enhanced HDPE transparency and package color fidelity), sealability above 205 degrees Celsius (°C), lower coefficient of friction (COF) properties, and a significant increase in the abrasion resistance of the polyolefin film. By using coated polyolefin films having the coating of the present invention, it becomes possible to construct packaging materials consisting entirely of polyolefin for packaging applications, achieving beneficial mechanical recyclability of the packaging material. In addition to the film having advantageous recyclability properties, other beneficial properties of the film include a long pot life and high abrasion resistance.

[0011] According to one embodiment, the present invention relates to a heat-sealable, recyclable coated polyolefin film. The coated film comprises a combination of (a) a recyclable polyolefin polymer layer and (b) a WB acrylic high-gloss coating layer having recyclable properties.

[0012] In some embodiments, the present invention includes a method for producing the above-described coated film.

[0013] In some embodiments, the present invention includes a first article made from the above-mentioned coated film, such as pellets, single-layer films, multilayer films, single-layer laminates, multilayer laminates, packaging materials, and molded products.

[0014] In some embodiments, the present invention includes a subsequent second article made from recycled material derived from any one of the first articles described above.

[0015] Advantageously, the first article manufactured incorporating the above-mentioned WB acrylic gloss coating film can be subjected to a recycling process in accordance with current recycling characteristics guidelines for the packaging industry. For example, by using the WB acrylic coating composition of the present invention, which is an acrylic system, in combination with a polymer film structure such as an all-polyethylene high-density polyethylene film or an all-polypropylene film, a film structure is provided that can be reprocessed to produce a new second article having substantially the same properties and performance as the first article. [Modes for carrying out the invention]

[0016] With respect to polyolefin film articles having a WB acrylic coating, "recyclable" and "recyclability" as used herein mean mechanically recyclable or mechanically recyclable, and that the film article having a WB acrylic coating can be mechanically reprocessed to produce another subsequent recycled article having the desired performance and characteristics.

[0017] With respect to polyolefin film articles, "heat-sealable" and "heat-sealable" as used herein mean a film having two sides, one side of which is coated with a coating layer and the other side of which is uncoated, where the uncoated side of the film is heat-sealable and the coated side of the film is not heat-sealable.

[0018] In one broad embodiment, the present invention includes a recyclable coated film structure for producing packaging material that can be recycled at the point of sale. The recyclable coated film comprises a combination of at least one heat-sealable and recyclable polyolefin film layer substrate coated with a coating layer. The coating layer is disposed on at least a portion of one face of the polyolefin film layer.

[0019] According to one or more embodiments of the present invention, the polyolefin film layer, which is component (a) of the heat-sealable and recyclable coated film structure, comprises, for example, a polyolefin film containing an ethylene-based polymer, and the coating layer, which is component (b) of the heat-sealable and recyclable coated film structure, comprises, for example, a recyclable WB acrylic high-gloss coating layer having recyclable properties, wherein the recyclable WB coating layer is compatible with the polyolefin layer. Generally, the recyclable polymer film layer has an outer (or external or top) surface and an inner (or internal or bottom) surface, and the coating layer has an outer (or external or top) surface and an inner (or internal or bottom) surface. At least a portion of the inner surface of the coating layer is in contact with at least a portion of the outer surface of the polyolefin film layer. In a preferred embodiment, the outer surface of the coating layer forms the outer surface of the entire coated film structure (i.e., polyolefin layer + coating layer). For example, in a general embodiment, the coated film of the present invention comprises (a) at least one polyolefin film layer, such as a polyethylene (PE) film, and (b) a WB acrylic coating layer bonded to the polyolefin film. If desired, one or more other optional film layer substrates can be added to the above film structure to produce a multilayer film structure.

[0020] In one or more embodiments, the polyolefin film web or layer, which is component (a) used to produce the film structure of the present invention, may comprise a single layer made from one or more polyolefins or olefin polymers, or the film structure may comprise a multilayer structure made from one or more polyolefin layers. As used herein, the terms “olefin polymer,” “olefin polymer,” and “polyolefin” refer to a polymer that, in its polymerized form, comprises a majority of olefin monomers (based on the weight of the polymer), such as ethylene or propylene, and may optionally comprise one or more comonomers. The term “polymer” refers to a polymer compound prepared by polymerizing monomers, whether of the same or different types. Thus, the general term polymer encompasses the term “homopolymer,” which is usually used to refer to a polymer prepared from only one type of monomer, and “copolymer,” which refers to a polymer prepared from two or more different monomers.

[0021] In other embodiments, the polyolefin film of the present invention may be a multilayer film having two or more layers. As described herein, “multilayer film” means any film having two or more layers. For example, a multilayer film may have two, three, four, five, or more layers. A multilayer film may be described as having layers indicated by letters to aid in describing the film. For example, a three-layer film 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. In some embodiments, the polyolefin film may be a co-extruded film having an odd number of layers, such as 3 to 11 or 3 to 7. For example, in some embodiments, the polyolefin film layers may be a three-layer multilayer film composed of three layers of polyethylene.

[0022] In one or more embodiments, the polyolefin layer may comprise an ethylene-based polymer. As described herein, "polyethylene" or "ethylene-based polymer" shall mean a polymer containing units derived from ethylene monomers in an amount greater than (>) 50 mol%. This includes ethylene-based homopolymers or copolymers (meaning that the units are derived from two or more comonomers). Common forms of polyethylene known in the art include, but are not limited to, LDPE, linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), single-site catalyst LLDPE including both linear low density resins and substantially linear low density resins, medium density polyethylene (MDPE), and HDPE. For example, the polyolefin layer can include one or more polyolefin layers such as HDPE, LDPE, LLDPE, MDO PE, BOPE, and mixtures thereof.

[0023] In one preferred embodiment, the polyolefin film layer can comprise a stretched monolayer or multilayer PE film made using either a machine direction stretching process or a biaxial stretching process and adhered to the second layer.

[0024] In another preferred embodiment, the polyolefin film layer can be a multilayer film comprising one or more layers of HDPE, LLDPE, and LDPE.

[0025] In yet another preferred embodiment, the polyolefin film layer can be a polypropylene (PP) film or a BOPP film layer.

[0026] In yet another preferred embodiment, the polyolefin film layer may be a film layer of a copolymer of polyethylene and propylene.

[0027] The thickness of the first polyolefin film layer used to form the heat-sealable and recyclable film of the present invention may be, for example, 12 microns (μm) to 500 μm in one embodiment, 20 μm to 250 μm in another embodiment, and 25 μm to 100 μm in yet another embodiment.

[0028] Furthermore, as described herein, the term “LDPE” may also be referred to as “high-pressure ethylene polymer” or “highly branched polyethylene,” and is defined as meaning that the polymer is partially or completely homopolymerized or copolymerized in an autoclave or tubular reactor at a pressure greater than 14,500 psi (100 megapascals [MPa]) using a free radical initiator such as a peroxide (see, for example, U.S. Patent No. 4,599,392). LDPE resins typically have a viscosity of 0.916 grams / cubic centimeter (g / cm³). 3 ) ~0.940g / cm³ 3 It has a density within the range.

[0029] As described herein, the term “LLDPE” may include resins prepared using the Ziegler-Natta catalyst system, as well as resins prepared using single-site catalysts, including but not limited to bis-metallocene catalysts (sometimes referred to as “m-LLDPE”), phosphine imines, and geometrically constrained catalysts; and resins prepared using post-metallocene molecular catalysts, including but not limited to bis(biphenylphenoxy) catalysts (also referred to as polyvalent aryloxy ether catalysts). LLDPE comprises linear, substantially linear, or heterogeneous ethylene copolymers or homopolymers. LLDPE contains fewer long-chain branches than LDPE and includes, for example, substantially linear ethylene polymers as further defined in U.S. Patents 5,272,236, 5,278,272, 5,582,923 and 5,733,155, uniformly branched ethylene polymers as 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 blends thereof (such as those disclosed in U.S. Patents 3,914,342 or 5,854,045). LLDPE resins can be produced by gas-phase, solution-phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0030] Furthermore, as described herein, the term "HDPE" generally refers to a product prepared using a Ziegler-Natta catalyst, a chromium catalyst, or even a metallocene catalyst, with a concentration of approximately 0.940 g / cm³. 3 This refers to polyethylene having the above density. In one or more embodiments, the polyolefin film layer may be a multilayer film including an outer layer containing an ethylene-based polymer.

[0031] Examples of such ethylene-based polymers include, but are not limited to, those commercially available from Dow Inc., such as ELITE® 5960G, ELITE® 5390, DOW® DGDP-6097, DOW® DMDA-8905NT, DOW® DGDC-2100NT, and similar known polymers commercially available from other suppliers such as Dow Inc. or Exxon Mobil.

[0032] In one or more embodiments, the polyolefin film layer may have a thickness of (≦) 1 millimeter (mm) or less, for example, ≦900 μm, ≦800 μm, ≦700 μm, ≦600 μm, ≦500 μm, ≦400 μm, ≦300 μm, or even ≦200 μm. The polyolefin film layer may have a thickness of (≧) 1 μm, ≧5 μm, ≧10 μm, ≧20 μm, ≧30 μm, ≧40 μm, or even ≧50 μm or more. As will be understood by those skilled in the art, in a multilayer film, the thicknesses of different layers may be the same or different, and the thicknesses of the layers may be selected by techniques known to those skilled in the art based on the disclosures herein.

[0033] In yet another embodiment, the polyolefin film layer of the coated polyolefin film may include a lamination of various different polyolefin films laminated together with a recyclable laminating adhesive.

[0034] The coating layer, which is component (b) used to coat the polyolefin layer, is advantageously formed from a coating composition having recyclable properties. Articles manufactured from a film structure containing a recyclable coating, such as packaging articles, are given acceptable recyclability compared to packaging articles made from a recyclable film structure.

[0035] In one embodiment, a useful WB coating composition in the present invention is, for example, a novel WB acrylic coating crosslinked with a water-dispersible polyisocyanate. In a preferred embodiment, the WB acrylic coating is formulated from a hydroxyl-functionalized acrylic emulsion and additives other than inorganic pigment particles. In some preferred embodiments, the additives may include, for example, binders, rheology modifiers, wetting agents, dispersants, slip agents, and mixtures thereof. In one preferred embodiment, the coating composition may include, for example, acrylates, polyesters, polycarbonates, and mixtures thereof.

[0036] In one embodiment, the water-dispersible polyisocyanate crosslinking agent can be a water-dispersible aliphatic polyisocyanate, such as MOR-FREE CR 9-101, which is commercially available from Dow Inc.

[0037] The coating composition of the present invention is useful for producing films that will be used later to manufacture packaging products such as packaging fresh produce, frozen produce, meat, liquid foods, dried foods, and general snacks.

[0038] In some embodiments, the coating composition advantageously has long pot life characteristics. For example, the pot life may range from 3 hours (hr) to 12 hours in one common embodiment, 4 hours to 12 hours in another embodiment, 5 hours to 10 hours in yet another embodiment, and 6 hours to 8 hours in yet another embodiment. In preferred embodiments, the pot life of the coating composition exceeds 6 hours. If the pot life of the coating composition is less than 3 hours, running ability problems arise during the application process of the composition. Pot life is measured by coating ability, which means that an acceptable coating appearance is still achieved at a given time.

[0039] The coating compositions useful in the present invention have several other beneficial properties compared to other known coating compositions, including, for example, high gloss, excellent abrasion resistance, heat seal resistance, and low COF.

[0040] According to one or more embodiments, at least a portion of the outer surface of the coating layer surface of a coated film including a coating layer has a desired optical gloss finish. As described herein, these optical properties are achieved by the processing steps currently disclosed during the manufacture of the coated film. For example, in one or more embodiments, at least a portion of the surface of a coated film having a coating layer has a gloss of 60 to 130 gloss units at 60° (60 degrees). As described herein, gloss is measured by utilizing the ASTM D2457 standard. In additional embodiments, the gloss units at 60° may be 40 to 50 gloss units, 50 to 60 gloss units, 60 to 70 gloss units, 70 to 80 gloss units, 80 to 90 gloss units, 90 to 100 gloss units, 100 to 130 gloss units, or any combination thereof. For example, the gloss at 60° may be in the range of 40 to 130 gloss units. In other embodiments, the gloss at 60° may be at least 50 gloss units, at least 60 gloss units, at least 70 gloss units, at least 80 gloss units, or at least 90 gloss units; the maximum may be ≤130 gloss units, ≤120 gloss units, ≤110 gloss units, ≤100 gloss units, or ≤90 gloss units.

[0041] In some embodiments, the coating layer advantageously has high abrasion resistance. For example, abrasion resistance may range from 50 or more friction cycles in one common embodiment, as measured by the Sutherland friction resistance test; from 50 to 2,000 friction cycles in another embodiment; and from 50 to 1,000 friction cycles in yet another embodiment. Abrasion resistance lower than 50 friction cycles may cause scratches and damage to the appearance of the packaging during packaging and transportation. Therefore, a greater number of friction cycles than 50 is preferred.

[0042] In some embodiments, the coating layer advantageously provides a film structure in which one side of the coating layer has high heat-sealing properties while the uncoated side is subjected to heat-sealable conditions. For example, the heat-sealing properties of the coating layer may be within a temperature range of ≥130°C in one general embodiment; 135°C to 220°C in another embodiment; 140°C to 210°C in yet another embodiment; and 150°C to 205°C in yet another embodiment. Heat-sealing properties below 130°C result in inefficient heat sealing, while heat-sealing properties above 220°C can lead to a breakdown of the heat-sealing resistance of the coated side. Thus, problems arise with pouching and packaging processing lines.

[0043] In one common embodiment, the coating weight of the coating layer on the polyolefin layer of the coated film structure is 1.1 grams per square meter (gsm or g / m²). 2 ) up to 4.0 gsm; in another embodiment, it may be in the range of 1.6 gsm to 3.2 gsm. Coating layers with a coating weight of less than 1.1 gsm result in lower performance, while coating layers with a coating weight of more than 4.0 gsm may cause potential problems with appearance, higher cost, and drying efficiency.

[0044] When a coating layer is applied to a polyolefin layer and cured, the coating layer is formed on one side of the polyolefin layer, resulting in a coated film having a coated side and an uncoated side. In some embodiments, the uncoated side of the coated film has sufficiently high heat-seal properties so that the coated film can be formed on articles such as packaging articles under heat-sealing conditions. For example, the heat-seal properties of a coated film may be in a temperature range of 130°C to 220°C in one common embodiment; 140°C to 210°C in another embodiment; and 150°C to 205°C in yet another embodiment. A coated film with a heat-seal properties below 130°C results in heat-sealed articles such as packages that are inefficiently and unsatisfactorily heat-sealed, which then leads to leakage of the package. A coated film with heat-seal properties above 220°C may cause problems related to, for example, poor packaging appearance and heat-seal resistance on the coated side, which can lead to problems in pouching and packaging processing lines.

[0045] In some embodiments, the coated film also has other beneficial properties, including, for example, improved color retention of a polyolefin film.

[0046] The film structure of the present invention may include, in addition to the component layers (a) and (b) described above, other optional substrate layers, component (c). For example, in some embodiments, the polyolefin film structure may include a printed layer on the upper surface of the polyolefin layer, and the printed layer may be in contact with a coating layer, thus forming a multilayer film structure in which the printed layer is positioned between the polyolefin layer and the coating layer. In such embodiments, the coating composition may be applied directly onto the printed layer. The printed layer may be an ink layer for displaying product details and other packaging information in various colors. The printed layer may be ≤15 μm in one general embodiment, ≤10 μm in another embodiment, ≤5 μm in yet another embodiment, and ≤2.5 μm in yet another embodiment.

[0047] In another embodiment, the printed layer may be on the other side of the coated polyolefin film and further laminated with another heat-sealable polyolefin film or another multilayer polyolefin film and a laminating adhesive.

[0048] If desired, any layer having a specific function, such as a sealant layer, barrier layer, tie layer, or a combination thereof, can be added to the coated film structure by co-extrusion or lamination with a laminating adhesive.

[0049] In one or more embodiments, if any layer is used, the thickness of any layer may be, for example, 1 μm to 100 μm in one embodiment, 2 μm to 70 μm in another embodiment, and 3 μm to 50 μm in yet another embodiment.

[0050] In one broad embodiment, the heat-sealable and recyclable coated film of the present invention is manufactured by applying the above-described coating composition onto the surface of a polyolefin film substrate to form a coating layer on the surface of the polyolefin film substrate. According to one or more embodiments, the coated film of the present invention may be manufactured by a method generally comprising the steps of applying an uncured coating composition to at least a portion of the outer surface of a polyolefin film layer, and curing the uncured coating composition to form a coating layer on the polyolefin layer to obtain the coated film structure of the present invention. The application of the uncured coating composition may be such that the outer surface of the polyolefin layer is in contact with the inner surface of the coating layer.

[0051] For example, in one general embodiment, a method for producing a heat-sealable and recyclable film includes the steps of (I) providing (a) a polyolefin film substrate and (b) a coating composition; (II) applying the coating composition to at least a portion of the surface of the polyolefin substrate to form a coating layer; and (III) curing the recyclable coating composition to form a cured coating layer on the upper surface of the polyolefin substrate from step (II) to form a coated film. As described herein, “applying” the coating composition to the polyolefin layer substrate may include bringing the coating composition into contact with the polyolefin layer by any conventional means known in the art for applying a coating composition or formulation to a film substrate. For example, the coating composition can be applied using conventional film forming apparatus and processes, including gravure printing, flexographic printing, offset printing, and Meyer rod drawdown. In some embodiments, the above-described coating application process may be performed, in one embodiment, before a lamination process is used, or in another embodiment, after a lamination process is used.

[0052] In one or more embodiments, the application of the uncured coating composition may be carried out by a lamination process in a conventional laminating machine. For example, according to one or more embodiments, the uncured coating composition may be applied to a polyolefin film layer as the polyolefin film layer moves parallel to the machine direction. That is, the polyolefin film layer may be conveyed in the machine direction while the uncured coating composition is being applied. As described herein, the machine direction refers to the direction in which the film flows onto or into a processing machine such as a laminating machine. The uncured coating composition may be deposited on the polyolefin film layer using either a smooth roll or a gravure roll, which may be selected at least in part by the viscosity of the uncured coating composition. The polyolefin film layer may begin in roll form, be unwound and conveyed in the machine direction, where the uncured coating composition is applied to the polyolefin layer, and then the polyolefin layer is wound back onto the roll.

[0053] According to embodiments disclosed herein, following the application of an uncured coating composition, the uncured coating composition can be dried and cured to form a coating layer comprising a cured coating composition layer disposed on the surface of a polyolefin layer. Curing can be “passive,” meaning that curing occurs by leaving the uncured coating composition at rest for a certain period of time under ambient conditions. Alternatively, curing can be accelerated by exposure to high temperatures, infrared (IR) radiation, or other mechanisms that can cause curing in the coating composition. In some embodiments, curing may occur while the polyolefin film layer and the uncured coating composition are rolled after lamination. After a certain period, the uncured coating composition solidifies, forming a roll of film comprising a coated film having the coating layer.

[0054] The coated film of the present invention can be used, for example, in packaging and lamination applications for packaging either food or non-food items, and in industries that readily utilize recyclable packaging. For example, the coated film of the present invention can be used in packaging applications for manufacturing various packaging materials and products before recycling. For example, the coated film can be used for bulk packaging of edible grains / legumes, seed packaging, lentil and grain packaging, fertilizer packaging, oilseed packaging, sugar packaging, salt packaging, pharmaceutical packaging, other food packaging, and personal care items such as bath salts and detergent pods. The coated film can also be used as packaging material for baby wipes, feminine hygiene products, cereal bars, protein bars, cheese and confectionery products. Other advantageous features and applications of the recyclable film when used in packaging articles include, for example, resistance to harsh weather conditions, high tensile strength, robust drop test resistance, excellent optical appearance, and resistance to leakage.

[0055] One of the advantages of the present invention is that used raw articles made from the coated film of the present invention can be easily processed through a recycling process. After recycling, subsequent recycled films can be made using the recycled material from the previous raw articles, and subsequently recycled articles can be made using the subsequent recycled films. The resulting subsequent recycled films can be advantageously used to manufacture subsequent recycled articles having properties and performance very close to those of the previous raw articles. For example, a new single-layer recycled film structure made from recycled material from a recycled article may exhibit a performance change of less than 50% compared to a control raw film similarly reprocessed without recycled material. In some embodiments, the new single-layer film structure may exhibit a performance change in the range of 0% to <50% in one embodiment, 0.01% to <40% in another embodiment, and 0.1% to <30% in yet another embodiment. The recycled film structure and the recycling performance of the recycled film structure meet the recyclability guidelines of The Association of Plastic Recyclers. [Examples]

[0056] The following examples and comparative examples of the present invention (collectively referred to as "Examples") are presented herein to further illustrate the present invention, but should not be construed as limiting the scope of the claims. Unless otherwise indicated, all parts and percentages are by weight.

[0057] The various materials used in the following examples are listed in Table I.

[0058] [Table 1]

[0059] Examples 1-9 and Comparative Examples A and B - Coating Compositions Part A: General Procedure for Preparing Coating Compounds The coating formulations of Invention Examples 1 to 9 described in Table II are prepared as follows.

[0060] Using a high-speed mixer, mix the ingredients in the given amounts shown in the formulations in Table II. First, add the acrylic emulsion polymer to the mixing vessel, followed by the defoaming agent. Then, while mixing at room temperature (RT, approximately 23°C), add the other additives one by one to the mixture in the mixing vessel.

[0061] The web coating is prepared by mixing the coating composition with a water-dispersible aliphatic polyisocyanate in an appropriate mixing ratio under an overhead mixer before applying the coating composition onto the polyolefin film substrate. The coated film substrate is then dried in a drying oven at 90°C for approximately 2 minutes (min).

[0062] The coating formulations of Comparative Examples A and B, as described in Table III, are prepared according to the recommendations shown in the product manufacturer's Technical Data Sheet (TDS). For example, the coating formulation of Comparative Example A or B is prepared by mixing the two components that make up the product under overhead mixing using a high-speed mixer, and then the coating composition is coated onto a polyolefin substrate at a given mixing ratio using RT and dried in a drying oven at 90°C for about 2 minutes.

[0063] Comparative Example C is an uncoated polyethylene film of ELITE(trademark) 5960 PE.

[0064] Part B: General Procedure for Preparing Coated Film Samples The wet coating composition prepared using the procedure in Part A is coated onto the surface of an HDPE film (made from ELITE 5960, 50 μm thick) using a K-coater equipped with a #2 drawdown bar. The target weight of the coating is 3.0 g / m². 2 ~3.5g / m 2It is. A QD printer equipped with a 120Q anilox roll in the flexo-proof is also used to prepare a coated film sample for testing in the flexographic printing process, aiming for a coating weight of 1.3 g / m 2 ~2.0 g / m 2 .

[0065] After applying the wet coating composition onto the HDPE film, the wet coating composition is dried at 90 °C for 2 minutes, and then the coated film sample is kept at room temperature for 7 days. After that, the coated film sample is subjected to a coating performance test.

[0066] Table II describes the components of the formulations of the coating compositions of Invention Examples 1 to 9 and the characteristics of the formulations. The viscosity and pot life of the wet coating composition samples are measured. The viscosity is measured using a Signature series viscosity cup, Zahn #3 cup.

[0067] Table III describes two commercially available formulations of the coating compositions of Comparative Example A and Comparative Example B and the characteristics of the formulations. The viscosity and pot life of the wet coating composition samples are measured. The viscosity is measured using a Signature series viscosity cup, Zahn #2 cup.

[0068]

Table 2

[0069]

Table 3

[0070] Comparative Example C Comparative Example C is the HDPE multilayer film itself (ELITE® 5960) with a thickness of 50 μm.

[0071] Examples 10-18 and Comparative Examples D and E - Coated Films Coating performance test The cured coatings were tested for gloss at 60° and 20° (20 degrees) according to ASTM D2457. Gloss was measured using a gloss meter at room temperature.

[0072] The hardened coating was tested for face-to-face Sutherland abrasion. Sutherland abrasion was tested using a SUTHERLAND® 2000RUB testing machine and a 1.81 kg load, in accordance with ASTM D5265.

[0073] The COF of the cured coating was measured in a control room (25°C, 50% humidity) using a COF tester manufactured by Testing Machines Inc.

[0074] Heat sealing performance was evaluated by heat sealing the coated sides facing each other at 205°C with a pressure of 0.276 MPa and a duration of 1 second using a heat sealer equipped with Teflon-coated heating jaws. A coating was designated "pass" if the coatings did not adhere to each other and the film did not shrink significantly after sealing. A coating was designated "fail" if the coatings adhered to each other and / or the film shrunk significantly after sealing. Table IV lists the coating performance results for the coated films.

[0075] [Table 4] *** No test was conducted. ****Coated film samples were prepared on 50 μm HDPE using a Labocombi pilot coater at 122 M / min. Data was collected after curing the samples at room temperature for 7 days. Coating weight = 1.5 g / m² 2

[0076] [Table 5]

[0077] It will be apparent that modifications and alterations are possible without departing from the scope of the invention as defined in the appended claims. More specifically, several aspects of the invention are identified herein as preferred or particularly advantageous, but the invention is intended not to be limited to these aspects.

[0078] In claims using the singular form, it should be clear that the possibility of a plural form is also included. For example, a reference to a coating layer implicitly includes a reference to at least one coating layer.

[0079] Note that one or more of the following claims utilize the term “wherein” as a transitional clause. Note that for the purposes of defining the present invention, the term “wherein” is introduced into the claims as an unrestricted transitional clause used to introduce an enumeration of a set of structural features and should be interpreted similarly to the more commonly used unrestricted preamble term “including.” Furthermore, although this application relates to the invention described in the claims, it may also encompass the following as other embodiments. [1] A glossy coated film having recyclable properties for packaging articles, (a) at least one film layer of recyclable polyolefin, (b) A combination comprising at least one coating layer disposed on a portion of one surface of the at least one film layer of the recyclable polyolefin, The at least one coating layer comprises an aqueous coating composition, The aforementioned coating layer has (1) heat-resistant sealing properties above 130°C, (2) Wear resistance for more than 50 friction cycles under a load of 1.81 kilograms, (3) A film having a gloss characteristic of 60° with a gloss unit of 90 or more, and (4) a recyclable characteristic in which the change in performance is less than 50 percent compared to a film without the coating layer. [2] The heat-resistant sealing properties are 130°C to 220°C, The aforementioned wear resistance is between 50 and 2000 friction cycles. The film according to [1] above, wherein the gloss characteristics at 60° are 90 gloss units to 130 gloss units, and the recyclability is a change in performance of 0.01 percent to less than 50 percent compared to a control unprocessed film reprocessed in the same manner without using any recycled material. [3] The film according to [1], wherein at least one film layer of the recyclable polyolefin is polyethylene. [4] The film according to [1], wherein the at least one coating layer is an aqueous acrylic coating formulated with a hydroxyl-functionalized emulsion and an additive that does not contain an inorganic pigment material, and the aqueous acrylic coating is cured using a water-dispersible aliphatic polyisocyanate. [5] Packaging articles made from the glossy coated film described in [1] above. [6] Recycled articles made from the glossy coated film described in [5] above. [7] A method for producing a glossy coated film having recyclable properties, (I)(a) Recyclable polyolefin film substrate, (b) A step of providing an aqueous coating composition, (II) A step of applying the aqueous coating composition of step (I) to at least a portion of the surface of the polyolefin substrate to form an aqueous coating composition coating layer, (III) A step of curing the aqueous coating composition to form a cured coating layer disposed on at least a portion of one surface of the polyolefin substrate of step (II) to form a coated film, The aforementioned coating layer has (1) heat-resistant sealing properties above 130°C, (2) Wear resistance for more than 50 friction cycles under a load of 1.81 kilograms, (3) A method having a gloss characteristic of 60° with 90 gloss units or more, and (4) a recyclability characteristic in which the change in performance is less than 50 percent compared to a polyolefin film without the coating layer. [8] A method for manufacturing recycled film articles, (i) The process of providing the packaged articles described in (4) above, (ii) A step of fragmenting the packaged article from step (A) into a plurality of pieces of a predetermined size, (iii) A step of pelletizing the plurality of fragments from step (B) to form a plurality of pellets of a predetermined size, (iv) A method comprising the step of processing the pellets from step (C) to form a recycled film article. [9] Recycled film articles manufactured by the method described in [8] above. (0) an aqueous coating composition, (A) at least one hydroxyl-functionalized emulsion polymer, (B) at least one crosslinking agent, (C) Water and, (D) At least one urethane-based thickener, (E) at least one slip agent, (F) comprising at least a combination agent, The aqueous coating composition provides a coating layer on a polyolefin film substrate. The aforementioned coating layer has (1) heat-resistant sealing properties above 130°C, (2) Wear resistance for more than 50 friction cycles under a load of 1.81 kilograms, (3) A water-based coating composition having a gloss characteristic of 60° with 90 gloss units or more, and (4) a recyclability characteristic in which the change in performance is less than 50 percent compared to a film without the coating layer.

Claims

1. A glossy coated film having recyclable properties for packaging articles, (a) at least one film layer of recyclable polyolefin, (b) A combination comprising at least one coating layer disposed on a portion of one surface of the at least one film layer of the recyclable polyolefin, The at least one coating layer comprises an aqueous coating composition. The coating layer has (1) heat-resistant sealing properties at temperatures of 130°C or higher, (2) Wear resistance for 50 or more friction cycles under a load of 1.81 kilograms, and (3) A film having a gloss characteristic of 60° with 90 gloss units or more.

2. The heat-resistant sealing properties are 130°C to 220°C. The aforementioned wear resistance is between 50 and 2000 friction cycles. The film according to claim 1, wherein the gloss characteristic at 60° is between 90 gloss units and 130 gloss units.

3. The film according to claim 1, wherein at least one film layer of the recyclable polyolefin is polyethylene.

4. The film according to claim 1, wherein the at least one coating layer is an aqueous acrylic coating formulated with a hydroxyl-functionalized emulsion and an additive that does not contain an inorganic pigment material, and the aqueous acrylic coating is cured using a water-dispersible aliphatic polyisocyanate.

5. A packaging article made from a glossy coated film as described in claim 1.

6. A recycled article made from the glossy coated film described in claim 5.

7. A method for producing a glossy coated film having recyclable properties, (I) (a) A recyclable polyolefin film substrate, (b) A step of providing an aqueous coating composition, (II) A step of applying the aqueous coating composition of step (I) to at least a portion of the surface of the polyolefin substrate to form an aqueous coating composition coating layer, (III) A step of curing the aqueous coating composition to form a cured coating layer disposed on at least a portion of one surface of the polyolefin substrate of step (II) to form a coated film, The coating layer has (1) heat-resistant sealing properties at temperatures of 130°C or higher, (2) Wear resistance for 50 or more friction cycles under a load of 1.81 kilograms, and (3) A method having a gloss characteristic of 60° with 90 gloss units or more.

8. A method for manufacturing recycled film articles, (i) A step of providing the packaged article described in claim 5, (ii) A step of fragmenting the packaged article from step (A) into a plurality of pieces of a predetermined size, (iii) A step of pelletizing the plurality of fragments from step (B) to form a plurality of pellets of a predetermined size, A method comprising (iv) processing the pellets from step (C) to form a recycled film article.

9. A recycled film article manufactured by the method described in claim 8.

10. A water-based coating composition, (A) at least one hydroxyl-functionalized emulsion polymer, (B) at least one crosslinking agent, (C) Water and, (D) At least one urethane-based thickener, (E) comprising at least one slip agent, The aqueous coating composition is cured and forms a coating layer on a polyolefin film substrate. The polyolefin film substrate has an ethylene-based polymer, The aforementioned coating layer is an aqueous acrylic coating, and is crosslinked with a water-dispersible polyisocyanate. The aqueous acrylic coating is formulated from additives other than a hydroxyl-functionalized acrylic emulsion and inorganic pigment particles. The coating layer has (1) heat-resistant sealing properties at temperatures of 130°C or higher, (2) Wear resistance for 50 or more friction cycles under a load of 1.81 kilograms, and (3) An aqueous coating composition having a gloss characteristic of 60° with 90 gloss units or more.

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