Barrier film

Abstract

A multilayer oxygen barrier film comprising a base film layer containing a polyolefin, an oxygen barrier layer containing a vinyl alcohol-based polymer, and a primer layer containing polyethyleneimine, wherein the primer layer contains at least about 0.005 g / m² 2 A method having a coat weight of [weight].

Description

[Technical Field]

[0001] This invention relates to a multilayer oxygen barrier film having good oxygen barrier properties maintained in the presence of moisture. The multilayer oxygen barrier film is suitable for use as a packaging film even in high humidity environments. [Background technology]

[0002] Films can be used to provide barrier properties against various compounds. For example, U.S. Patent Application Publication No. 2019322429 discloses a mineral oil barrier film. However, a commonly required barrier film is an oxygen barrier film that can be used to reduce the rate of oxygen permeation through the film.

[0003] Many materials are known to provide oxygen barrier properties to polymer packaging films. For example, polyvinyl alcohol (PVOH) is widely used as an oxygen barrier layer in packaging films. However, because PVOH is soluble in water and therefore prone to degradation when exposed to moisture, the PVOH layer suffers a loss of oxygen barrier performance in the presence of moisture. This means that packaging films containing a PVOH layer may not be suitable for use in packaging environments with high humidity levels.

[0004] Various methods are known in the prior art to avoid the problem of PVOH moisture sensitivity. One such method involves crosslinking PVOH to reduce its sensitivity to moisture. To achieve this, a crosslinking agent is typically added to the PVOH layer.

[0005] U.S. Patent No. 6,444,750 describes a polymer film structure with enhanced oxygen barrier, produced by a method that includes coating at least one polymer-based surface adapted to receive an oxygen barrier with a solution of polyvinyl alcohol, a formaldehyde-containing crosslinking agent, and a crosslinking-promoting acid catalyst. The pH of the aforementioned solution is about 3.5 or less, and the aforementioned acid catalyst is selected from the group consisting of phosphoric acid, nitric acid, and hydrochloric acid.

[0006] However, crosslinking agents can potentially reduce the shelf life of packaging films. Additionally, some crosslinking agents have associated health hazards and are not suitable for use in certain packaging applications, such as food packaging.

[0007] It is also known to include in the PVOH layer a component that reacts with PVOH to become more stable in the presence of moisture.

[0008] For example, European Patent No. 1,211,295 describes a gas barrier coating composition that includes (a) a polyvinyl alcohol resin and (b) at least one member selected from the group consisting of metal alcoholates, hydrolyzates of metal alcoholates, condensates of metal alcoholates, chelate compounds of metal alcoholates, hydrolyzates of chelate compounds, and metal acylates.

[0009] Another known method to address the problem of the moisture sensitivity of the PVOH layer is to include the PVOH layer as part of a laminated structure. For example, the PVOH layer may be coated on a film substrate. However, PVOH and similar compounds tend to exhibit insufficient adhesion to film bases, such as polyolefins.

[0010] To improve the adhesion of the PVOH layer to the film base, it is common to include an adhesion promoter in the PVOH layer.

[0011] For example, European Patent Application Publication No. 3842229 describes a water-resistant gas barrier film having at least a gas barrier layer disposed on a base film, the gas barrier layer being formed from a coating solution containing (a) at least one of carboxyl-modified polyvinyl alcohol and partially saponified polyvinyl alcohol, (b) fully saponified polyvinyl alcohol, and (c) polyethyleneimine. The polyethyleneimine acts as an adhesion promoter to bond the coating film to the base.

[0012] European Patent Application Publication No. 3405536 describes a primer coating comprising an aqueous mixture containing amorphous polyvinyl alcohol, an adhesion promoter containing one or more polyethyleneimines and polyurethanes, a crosslinking agent, and optionally a catalyst.

[0013] Films having a PVOH layer containing an adhesion promoter are also described in European Patent Publication No. 0960159, Japanese Patent Publication No. 2001 / 121658, European Patent Publication No. 2762539, European Patent Publication No. 2245092, European Patent Publication No. 2914670, and International Publication No. 22 / 124171.

[0014] However, like crosslinking agents, some adhesion promoters have associated health risks and are unsuitable for certain packaging applications, such as food packaging.

[0015] Primer layers have also been mentioned in the art as a way to improve adhesion between the PVOH layer and the film base. Primer layers prepare the polymer surface for the addition of further layers. Typically, primer layers are used to flatten the polymer surface and prepare it for receiving functional coatings.

[0016] International Publication No. 2022 / 084397 describes a multilayer system comprising at least the following layers: (a) a packaging sheet; (b) a primer layer on the packaging sheet containing at least one polymer having at least 5% by weight of carboxylic acid groups, wherein the at least one polymer has a carboxyl number of 50 to 200; and (c) a barrier layer on the primer layer containing at least one polyvinyl alcohol and / or at least one copolymer containing polyvinyl alcohol.

[0017] European Patent Application Publication No. 0461772 describes a combination of films comprising an oxygen-permeable polymer base, at least one of which is treated to a surface free energy of at least about 35 dynes / cm, and which has a primer coating thereon, and on this primer coating, an oxygen permeability inhibiting layer comprising crosslinked polyvinyl alcohol.

[0018] Polyurethane primer layers are frequently referenced in the art in combination with PVOH layers.

[0019] For example, U.S. Patent No. 4,927,689 describes a composite structure comprising a base synthetic thermoplastic polymer layer having two coatings on one side of the base layer, the first coating being adjacent to the base layer and being a solvent-based urethane primer, which, upon drying, contains an aqueous dispersion or solution of polyvinyl alcohol at a rate of 0.3 to 3.0 g / m² of the base layer. 2 This allows the primer to be "wetted" in amounts within this range, and the second coating is placed on the exposed surface of the first coating, at approximately 2.0 g / m². 2 The aforementioned second coating comprises an amount of polyvinyl alcohol gas barrier material in the range of up to , and is formed from a dispersion or solution.

[0020] U.S. Patent No. 6,106,950 describes a method for providing improved resistance to oxygen and moisture on at least one surface of a base, comprising: (a) coating at least one surface of the base with a primer layer composition, wherein the primer composition comprises (i) at least one aqueous polyurethane dispersion (A) and (ii) at least one crosslinking agent (B) selected from the group consisting of polyfunctional isocyanates and polyfunctional aziridines; (b) drying the base coated with the primer; (c) coating at least one surface of the primer layer with a barrier layer composition, wherein the barrier layer composition comprises (i) at least one aqueous polyvinyl alcohol or its copolymer (C) and (ii) at least one crosslinking agent (D) selected from the group consisting of polyethyleneimine, melamine, melamine derivatives and mixtures thereof; and (d) drying the coated base.

[0021] European Patent No. 3553115 describes a multilayer oxygen barrier film with improved heat and water resistance, comprising a base film layer formed from polyethylene terephthalate, nylon, polypropylene, or polyethylene, an oxygen barrier layer, and an adhesive layer formed between the base film layer and the oxygen barrier layer. The oxygen barrier layer contains polyvinyl alcohol in combination with silane, and the adhesive layer is a polyurethane primer layer.

[0022] However, in some cases, primer layers and adhesion promoters appear to have a detrimental effect on the overall oxygen barrier performance of the film. For example, a decrease in oxygen barrier performance is observed when using a polyurethane primer layer.

[0023] International Publication No. 9946120 describes a composite film structure intended to have very low oxygen permeability. This is achieved using two inorganic layers, preferably formed from metals, and a polymer barrier, which may be PVOH. These barrier layers are applied to a polyester film, which is known to have much higher oxygen barrier properties than polyolefin films, thereby further contributing to the oxygen barrier properties of this film.

[0024] Therefore, in this field, there is still a need for multilayer oxygen barrier films based on polyolefin films that have good oxygen barrier properties maintained in the presence of moisture and address the problems associated with conventional barrier films. [Overview of the project]

[0025] According to one aspect of the present invention, the invention comprises a base film layer containing a polyolefin, an oxygen barrier layer containing a vinyl alcohol-based polymer, and a primer layer containing polyethyleneimine, wherein the primer layer contains at least about 0.005 g / m² 2 A multilayer oxygen barrier film having a coating weight is provided.

[0026] The inventors of this invention have surprisingly found that the amount is at least about 0.005 g / m 2 We have found that by using a primer layer having a coat weight and containing polyethyleneimine in combination with an oxygen barrier layer containing a vinyl alcohol-based polymer, such as PVOH, the oxygen barrier performance of the entire film is significantly improved, even at relatively high relative humidity levels such as up to 50% RH. The inventors of this invention observed a synergistic oxygen barrier effect between the primer layer and the oxygen barrier layer, and although they do not wish to be bound by any such theory, they believe this may be due to the degree of crosslinking that occurs between the vinyl alcohol-based polymer, such as PVOH, and polyethyleneimine. The presence of the primer layer also provides a smoother surface to which the oxygen barrier layer can be applied, which is thought to improve the oxygen barrier performance of the layer.

[0027] This discovery is surprising because primer layers have traditionally been used to aid in interlayer adhesion in films. It was previously not recognized in the art that primer layers could impart or enhance specific properties of a film, such as oxygen barrier performance. This discovery is particularly unexpected because many primer layers in the art, used in combination with oxygen barrier layers, such as PVOH layers, do not make any difference to the oxygen barrier properties of the film, or even have a detrimental effect on them, especially polyurethane primer layers.

[0028] What makes this discovery of improved oxygen barrier performance even more unexpected is that the base film layer contains polyolefin. Polyolefin polymers are known to inherently have high oxygen permeability (OTR), for example, oriented polypropylene (OPP) has an OTR of approximately 1500-2500 cc / m². 2 Cast polypropylene (PP) has an OTR of 24 hours and a capacity of approximately 2300-3100 cc / m². 2 High-density polyethylene (HDPE) has an OTR of 24 hours and a density of approximately 2300-3100 cc / m² at 73°F (23°C) and 0%RH. 2 It has an OTR of / 24 hours. Therefore, polyolefin films have a lower oxygen barrier capacity compared to other polymer films that have an inherently low OTR, such as polyester films, with an OTR of approximately 31-93 cc / m² at 73°F (23°C) 0%RH. 2 It has an OTR of 24 hours. Surprisingly, the inventors of the present invention observed a significant increase in the oxygen barrier capacity of a multilayer oxygen barrier film containing a polyolefin-based film when using a combination of a vinyl alcohol-based polymer and a primer layer containing polyethyleneimine according to the present invention. Thus, this synergistic layer combination can, surprisingly, reduce the oxygen permeability through the polyolefin-based film to an acceptable level, even though the oxygen permeability of the polyolefin-based film itself is higher.

[0029] Thus, according to another aspect of the present invention, there is provided the use of a primer layer containing polyethyleneimine for reducing the oxygen transmission rate of a multilayer oxygen barrier film.

[0030] Advantageously, the improvement in the oxygen barrier performance of the film can be achieved without the need for a crosslinking agent in a vinyl alcohol-based polymer layer, such as a PVOH layer. The presence of the primer layer also eliminates the need to use an adhesion promoter to fix the oxygen barrier layer to the base film layer. As described above, some crosslinking agents and adhesion promoters have associated health hazards, so it is beneficial to have a multilayer oxygen barrier film that can be formulated without them.

[0031] Furthermore, the improvement in the oxygen barrier performance of the film provides the advantage that the multilayer oxygen barrier film of the present invention is suitable for use in a wide variety of packaging applications, including those where the packaging is exposed to moisture, such as in food packaging, even at relatively high relative humidities, such as up to 50%RH.

[0032] Thus, according to another aspect of the present invention, there is provided the use of a multilayer oxygen barrier film as a packaging film.

[0033] According to another aspect of the present invention, there is provided a package at least partially formed from a multilayer oxygen barrier film. The package may be a sealed package and may include a seal between two regions of the film.

[0034] According to another aspect of the present invention, there is provided an article encapsulated or packaged in a material containing a multilayer oxygen barrier film.

[0035] According to a further aspect of the present invention, there is provided a method for manufacturing a multilayer oxygen barrier film, comprising at least about 0.005 g / m 2A method is provided which includes the steps of applying a primer layer containing polyethyleneimine to at least one surface of a base film layer containing polyolefin at a coat weight, and coating the primer layer with an oxygen barrier layer containing a vinyl alcohol-based polymer.

[0036] In the following description, it will be understood that all features relating to one aspect of the present invention can, where appropriate, be applied to all other aspects of the present invention, and vice versa. [Modes for carrying out the invention]

[0037] The multilayer oxygen barrier film of the present invention comprises a base film layer, an oxygen barrier layer, and a primer layer.

[0038] The oxygen barrier layer contains a vinyl alcohol-based polymer.

[0039] Vinyl alcohol-based polymers may contain polyvinyl alcohol (PVOH) and / or ethylene vinyl alcohol (EVOH). Preferably, vinyl alcohol-based polymers contain polyvinyl alcohol.

[0040] The oxygen barrier layer may contain at least 70% by weight of a vinyl alcohol-based polymer, preferably at least 80% by weight of a vinyl alcohol-based polymer, at least 90% by weight of a vinyl alcohol-based polymer, at least 95% by weight of a vinyl alcohol-based polymer, or at least 98% by weight of a vinyl alcohol-based polymer.

[0041] The coating weight of the oxygen barrier layer can be selected based on the desired barrier properties of the film, and is generally about 0.1 g / m². 2 ~about 10g / m 2 It is within the range.

[0042] The oxygen barrier layer contains approximately 0.2 g / m². 2 ~about 5g / m 2 , or approximately 0.5 g / m 2 ~about 2g / m2 It may have a court weight of [weight].

[0043] In this context and throughout this specification, the term “coat weight” refers to the dry coat weight unless otherwise specified.

[0044] A multilayer oxygen barrier film may include a single oxygen barrier layer containing a vinyl alcohol-based polymer. It has been found that a single oxygen barrier layer significantly improves the oxygen barrier properties of the multilayer film without requiring any additional oxygen barrier layers. Therefore, the multilayer oxygen barrier film of the present invention provides a simpler overall multilayer structure compared to multilayer films of the art that require multiple oxygen barrier layers, while still maintaining effective oxygen barrier performance. A multilayer oxygen barrier film may include a single oxygen barrier layer containing a vinyl alcohol-based polymer on one side. A multilayer oxygen barrier film may include a single oxygen barrier layer on one side. A multilayer oxygen barrier film may include a single oxygen barrier layer.

[0045] In some embodiments, the multilayer oxygen barrier film may not include a second aqueous coating layer (i.e., the oxygen barrier layer containing a vinyl alcohol polymer is the only first aqueous coating layer present). The multilayer oxygen barrier film may not include a second aqueous coating layer on the surface of the polyolefin film having the oxygen barrier layer. The multilayer oxygen barrier film may not include a second aqueous coating layer directly on the oxygen barrier layer. Coating a second aqueous coating layer on the oxygen barrier layer can be difficult, and the water in the second coating is expected to disrupt the crystalline structure of the oxygen barrier layer. It has also been found to be unnecessary due to the improved barrier properties observed with the combination of the oxygen barrier layer and the PEI primer.

[0046] In some embodiments, the multilayer oxygen barrier film may include an additional solvent-based coating layer.

[0047] The oxygen barrier layer may not contain any crosslinking agent and / or adhesion promoter. In some cases, the oxygen barrier layer may not contain any crosslinking agent and may not contain any adhesion promoter. The oxygen barrier layer may also not contain a crosslinking-promoting acid catalyst. The crosslinking agent or adhesion promoter may include any suitable compound known in the art, such as polyamidoamine-epichlorohydrin (PAE) or polyethyleneimine (PEI).

[0048] In this context, the term “absent” preferably means that the amount of components (i.e., crosslinking agents or adhesion promoters) in the oxygen barrier layer is less than about 1% by weight of the layer, less than about 0.5% by weight of the layer, less than about 0.1% by weight of the layer, substantially less than 0% by weight of the layer, or the layer is completely absent, i.e., 0% by weight of the layer. To avoid doubt, these values ​​relate to the dry content of the layer. Adhesion promoters are thought to potentially disrupt the crystalline structure of the barrier layer, thereby degrading the barrier properties of the layer.

[0049] Alternatively, the oxygen barrier layer may contain a crosslinking agent and / or adhesion promoter.

[0050] Crosslinking agents and / or adhesion promoters may be present in small amounts, preferably less than 5% of the layer's weight, in the oxygen barrier layer. Crosslinking agents and / or adhesion promoters may also be present in amounts less than 4% by weight, less than 3% by weight, or less than 2% by weight of the layer. To avoid doubt, these values ​​relate to the dry content of the layer.

[0051] It has been found that including larger amounts of crosslinking agents or adhesion promoters in the oxygen barrier layer can have a detrimental effect on oxygen permeability, especially at relatively high humidity levels such as up to 50% RH.

[0052] The primer layer contains polyethyleneimine. The primer layer may consist of polyethyleneimine.

[0053] Polyethyleneimine may contain branched and / or linear polyethyleneimine components.

[0054] The primer layer contains at least approximately 0.005 g / m² 2 The coat has a weight of approximately 0.005 g / m². This minimum coat weight was found to be necessary for an effective improvement in the oxygen barrier properties of the film. The primer layer has a weight of approximately 0.005 g / m². 2 ~about 5g / m 2 , about 0.005g / m 2 ~about 2g / m 2 , about 0.005g / m 2 ~about 1g / m 2 , about 0.005g / m 2 ~about 0.5g / m 2 , about 0.005g / m 2 ~about 0.1g / m 2 , or approximately 0.005 g / m 2 ~about 0.05g / m 2 It may have a court weight of [weight].

[0055] The primer layer contains at least approximately 0.01 g / m² 2 The coat may have a weight of approximately 0.01 g / m². The primer layer may have a weight of approximately 0.01 g / m². 2 ~about 5g / m 2 , about 0.01g / m 2 ~about 2g / m 2 , about 0.01g / m 2 ~about 1g / m 2 , about 0.01g / m 2 ~about 0.5g / m 2 , about 0.01g / m 2 ~about 0.1g / m 2 , or approximately 0.01 g / m 2 ~about 0.05g / m 2 It may have a court weight of [weight].

[0056] The primer layer may be located between the base film layer and the oxygen barrier layer. Preferably, the primer layer is adjacent to the oxygen barrier layer, i.e., without any intervening layers. The primer layer can help the oxygen barrier layer adhere to the base film layer and can also improve the overall oxygen barrier performance of the film.

[0057] The base film layer contains polyolefin. At least one layer of the base film may consist of one or more polyolefins and other additives. The base film layer may be at least 50% polyolefin, preferably at least 75% polyolefin.

[0058] The base film layer may contain polyethylene, polypropylene, mixtures thereof, and / or other known polyolefins.

[0059] The base film layer may include polypropylene, and optionally biaxially oriented polypropylene. The biaxially oriented polypropylene base film layer may be prepared as a balanced film using substantially equal longitudinal and transverse stretches, or as an unbalanced film in which the film is significantly further oriented in one direction (MD or TD). Sequential stretching or simultaneous stretching can be used to form the base film layer. Simultaneous stretching can be achieved using the so-called bubble process or simultaneous stretching stent stretching.

[0060] The base film layer may further contain polyester, polyamide, polystyrene, polyurethane, polyhalogenated vinyl, acetate, or biopolymer.

[0061] The base film layer may be a single layer or a multilayer structure. For example, the base film layer may include, for example, a polypropylene core layer and one or more co-extruded skin layers. The skin layers may be, for example, a sealing layer and / or a laminate layer. The skin layers may include, for example, a copolymer of ethylene and propylene, or a terpolymer of propylene, ethylene and butylene.

[0062] As a specific example, the base film layer may include a core layer, for example, made of polypropylene, having co-extruded skin layers on both sides thereof. The film may be heat-cured to reduce or eliminate shrinkage.

[0063] A multilayer oxygen barrier film may include one or more additional layers selected from sealable layers, e.g., heat-sealable layers; printable layers; metallized layers; metal layers (e.g., laminated sheet layers); and / or functional and / or aesthetic coatings.

[0064] Therefore, in some embodiments, the multilayer oxygen barrier film may include a metallized layer or a metal layer.

[0065] Alternatively, in some embodiments, the multilayer oxygen barrier film may not include a metallized layer or a metal layer. The inventors have found that improved oxygen barrier properties and low oxygen permeability can be achieved without the need for a metallized layer, particularly for 0-50% RH.

[0066] The multilayer oxygen barrier film or any of its layers may contain additional materials such as antiblocking additives, opacifiers, fillers, UV absorbers, colorants, antistatic agents, antioxidants, cavitation agents, and slip additives.

[0067] The multilayer oxygen barrier film according to the present invention can have various thicknesses depending on the application requirements. For example, the thickness of the multilayer barrier film can range from about 10 μm to about 240 μm.

[0068] The multilayer oxygen barrier film is preferably about 5 cm³ at 0% relative humidity when measured according to ASTM D3985. 3 / m 2 / Less than 24 hours, or about 3cm 3 / m 2 / Less than 24 hours, or about 1 cm 3 / m 2 Less than 24 hours, or approximately 0.5 cm 3 / m 2 This indicates oxygen permeability for less than 24 hours.

[0069] The multilayer oxygen barrier film preferably has a humidity of about 20 cm at 50% relative humidity, as measured according to ASTM F1927-14. 3 / m 2 / Less than 24 hours, or about 10 cm 3 / m 2 / Less than 24 hours, or about 5 cm 3 / m 2 / Less than 24 hours, or about 3cm 3 / m 2 This indicates oxygen permeability for less than 24 hours.

[0070] The multilayer oxygen barrier film of the present invention preferably has an OTR at 0% relative humidity that is at least 10%, preferably at least 20%, and more preferably at least 30% lower than that of a corresponding film of the same structure that does not include a primer layer.

[0071] The multilayer oxygen barrier film of the present invention can be used as a packaging film, for example, in food packaging.

[0072] Furthermore, the present invention provides a package formed at least partially from a multilayer oxygen barrier film. The package may be a sealed package and may include a seal between two regions of the multilayer barrier film.

[0073] Furthermore, the present invention provides an article that is encased or packaged in a material containing a multilayer oxygen barrier film.

[0074] Furthermore, according to the present invention, a method for producing a multilayer oxygen barrier film is provided, wherein the amount is at least about 0.005 g / m². 2 A method is provided which includes the steps of applying a primer layer containing polyethyleneimine to at least one surface of a base film layer with a coat weight of , and coating the primer layer with an oxygen barrier layer containing a vinyl alcohol-based polymer.

[0075] The composition of the present invention does not require a multi-step process or multiple-pass process such as the deposition of an inorganic metal oxide layer, thereby enabling the use of a simple and inexpensive coating method.

[0076] Vinyl alcohol-based polymers may contain polyvinyl alcohol.

[0077] The method may further include, prior to step a, a step of corona-treating the surface of the base film layer to which the primer layer is applied.

[0078] The primer layer and / or oxygen barrier layer can be applied using standard coating techniques, such as roller coating methods including gravure or reverse gravure, slot die coating, semi-flexographic coating, slide coating, or curtain coating.

[0079] Both vinyl alcohol-based polymers and polyethyleneimines can be provided as solutions that are coated onto a base film layer and subsequently dried.

[0080] Vinyl alcohol-based polymer solutions may have a solid content of approximately 1% to 50% by weight relative to the solution, or approximately 5% to 20% by weight relative to the solution. Polyethyleneimine solutions may have a solid content of approximately 1% to 20% by weight, or approximately 2% to 10% by weight relative to the solution.

[0081] Vinyl alcohol-based polymer solutions may have a pH of approximately 11 or less, approximately 10 or less, approximately 9 or less, approximately 8 or less, approximately 7 or less, approximately 6 or less, approximately 5 or less, approximately 4 or less, or approximately 3 or less. Vinyl alcohol-based polymer solutions may have a pH of approximately 4 or more, approximately 5 or more, or approximately 6 or more.

[0082] The use of a primer layer containing polyethyleneimine to reduce the oxygen permeability of a multilayer oxygen barrier film is also provided according to the present invention.

[0083] Surprisingly, it was found that using a polyethyleneimine primer layer could improve the oxygen barrier properties of the film, in addition to enhancing the adhesion of the layers. The barrier effect was at least about 0.005 g / m². 2This is particularly advantageous in terms of court weight.

[0084] example The present invention will now be described in more detail with reference to the following non-limiting examples.

[0085] Example 1 (Comparative Example) A 25μm polypropylene-based film was heated in a 1.8m oven at 15.4 W / min / m². 2 The film was boosted (corona) on the corona-treated surface at a power density of 20 m / min, an operating speed of 20 m / min, and a drying temperature of 100°C.

[0086] Using a Pilot RK coater, a PVOH coating (Mica® EL-1421 HS) was applied directly onto the boosted surface of the base film. The PVOH coating was applied at a rate of 1 g / m². 2 The dry coating was applied with a 10% solids content using 120 Trihelical Gravure with reverse gravure coating technology, based on the coat weight of the dry coating.

[0087] Example 2 A 25μm polypropylene-based film was heated in a 1.8m oven at 15.4 W / min / m². 2 The film was boosted (corona) on the corona-treated surface at a power density of 20 m / min, an operating speed of 20 m / min, and a drying temperature of 100°C.

[0088] A polyethyleneimine primer layer (Mica® WBA-131-X) was applied to the corona-treated surface of the film using a pilot RK coater. The polyethyleneimine primer layer was applied using reverse gravure and 250Q gravure at a rate of 0.02 g / m². 2 The target coat weight was obtained. The process was performed in a 1.8m oven at a drying temperature of 75°C with a running speed of 40m / min.

[0089] Next, a PVOH coating (Mica® EL-1421 HS) was applied to the primer layer using a pilot RK coater. The PVOH coating was applied at a rate of 1 g / m².2 The dry coating was applied with a 10% solids content using 120 Trihelical Gravure with reverse gravure coating technology, based on the coat weight of the dry coating.

[0090] Example 3 (Comparative Example) A 25μm polypropylene-based film was heated in a 1.8m oven at 15.4 W / min / m². 2 The film was boosted (corona) on the corona-treated surface at a power density of 20 m / min, an operating speed of 20 m / min, and a drying temperature of 100°C.

[0091] A polyurethane primer layer (Covestro® NeoRez® R-610) was applied to the corona-treated surface of the film using a pilot RK coater. The polyurethane primer layer was applied using reverse gravure and 250Q gravure at a rate of 0.02 g / m². 2 The target coat weight was obtained. The process was performed in a 1.8m oven at a drying temperature of 75°C with a running speed of 40m / min.

[0092] Next, a PVOH coating (Mica® EL-1421 HS) was applied to the primer layer using a pilot RK coater. The PVOH coating was applied at a rate of 1 g / m². 2 The dry coating was applied with a 10% solids content using 120 Trihelical Gravure with reverse gravure coating technology, based on the coat weight of the dry coating.

[0093] Example 4 - Oxygen permeability at different relative humidity levels The film samples prepared in Examples 1-3 were evaluated for oxygen permeability at 0% and 50% relative humidity according to the standard test methods ASTM D3985 and ASTM F1927-14, respectively. The data shown in Table 1 are the average of two repeated tests for each sample. [Table 1]

[0094] The results show that the use of polyethyleneimine primer significantly reduces the oxygen permeability of the film at 0% and 50% RH. Conversely, the use of polyurethane primer appears to have a detrimental effect on the oxygen barrier properties of the film. These findings support the present invention's concept of a synergistic effect between polyethyleneimine primer and PVOH functionality that improves oxygen barrier performance.

[0095] Example 5 - Effect of adhesion promoter versus primer layer Various film samples were prepared with the compositions shown in Table 2 using one of the general methods outlined in Example 1 (without primer), Example 2 (with PEI primer), or Example 3 (with polyurethane primer).

[0096] Film samples A through H were evaluated for oxygen permeability at 0% and 50% relative humidity according to the standard test methods ASTM D3985 and ASTM F1927-14, respectively. The data shown in Table 2 are the average of two repeated tests for each sample. [Table 2]

[0097] The results for samples A to F show that using a PEI primer layer with a PVOH coating increases the oxygen barrier of the film at both 0% RH and 50% RH (Sample B).

[0098] Comparing Sample A and Sample D, it appears that adding a higher amount of PEI adhesion promoter, i.e., a 10 wt% layer, provides little additional benefit to the film's oxygen barrier and may even be damaging at 50% RH. Indeed, Sample E exhibits slightly worse oxygen permeability than Sample B at 0% RH, demonstrating that these samples have a greater detrimental effect from the addition of PEI adhesion promoter at 50% RH, even in the presence of a PEI primer layer.

[0099] Comparing the results of Sample C and Sample F further demonstrates the potential adverse effects of using PEI adhesion promoters in higher amounts, i.e., 10 wt% layers. In these samples, adverse effects on oxygen permeability are observed at both 0% RH and 50% RH. Comparing the results of Sample C and Sample F with those of Sample B and Sample E, respectively, also highlights the advantages of using PEI primers compared to polyurethane primers in terms of oxygen permeability at both 0% and 50% RH.

[0100] The results for samples G-J show that using a PEI primer layer with a PVOH coating increases the oxygen barrier of the film at both 0% RH and 50% RH (sample H). The addition of a PAE adhesion promoter appears to increase the oxygen barrier of the film at 0% RH. However, it appears to have a detrimental effect on the oxygen barrier at 50% RH. Additionally, the oxygen permeability of sample J is worse than that of sample H at 50% RH, demonstrating the detrimental effect of the adhesion promoter on oxygen barrier properties when used in larger quantities.

[0101] Example 6 - PVOH coating weight, primer, adhesion promoter, and metallization effect Using the general method outlined in Example 2 (one of two different PEI primers), various film samples were prepared with the compositions shown in Table 3.

[0102] When an adhesion promoter was used, it was blended with the PVOH coating at a dry content of 1.95% by weight per layer.

[0103] The samples were metallized using a Bobst K5 metallizer at 300 m / min under standard metallization conditions.

[0104] Film samples K to P were evaluated for oxygen permeability at 50% relative humidity according to the standard test method ASTM F1927-14. The data shown in Table 3 are the average of two repeated tests for each sample. Water vapor permeability was evaluated according to the standard test method ASTM F1249-13. [Table 3]

[0105] The results for samples K and M suggest that the presence of adhesion promoters can negatively affect the oxygen barrier capacity of the resulting multilayer film.

[0106] Comparing the results for L and M, there appears to be no significant difference in oxygen permeability between the two PEI primers.

[0107] Comparing the results for M and N, it can be seen that there is a significant difference in oxygen permeability and water vapor permeability between the case with a high PVOH coating weight and the case with a low PVOH coating weight. PVOH 1.0g / m 2 The higher coat weight is PVOH 0.5g / m 2 This shows a significant increase in the oxygen barrier of the film compared to the previous case.

[0108] Comparing the results for K and O, metallization with Al appears to provide improved oxygen barrier capacity and reduced oxygen permeability compared to AlOx. However, the metallized films in Table 3 provide a better oxygen barrier than the non-metallized films in Table 2.

Claims

1. A multilayer oxygen barrier film, A base film layer containing polyolefin, An oxygen barrier layer containing a vinyl alcohol-based polymer, and A primer layer containing polyethyleneimine and Includes, The primer layer contains at least about 0.005 g / m² ２ A multilayer oxygen barrier film having a coating weight of [weight].

2. A multilayer oxygen barrier film according to claim 1, comprising a single oxygen barrier layer containing a vinyl alcohol-based polymer.

3. The multilayer oxygen film according to claim 1 or 2, wherein the multilayer film does not include a second aqueous coating layer.

4. The multilayer oxygen barrier film according to any one of claims 1 to 3, wherein the vinyl alcohol-based polymer comprises polyvinyl alcohol and / or ethylene vinyl alcohol.

5. The multilayer oxygen barrier film according to any one of claims 1 to 4, wherein the vinyl alcohol-based polymer contains polyvinyl alcohol.

6. The oxygen barrier layer has a density of approximately 0.1 g / m². ２ ~Approx. 10g / m ２ , about 0.2g / m ２ ~Approx. 5g / m ２ , or approximately 0.5 g / m ２ ~About 2g / m ２ A multilayer oxygen barrier film according to any one of claims 1 to 5, having a coating weight of [amount missing].

7. The multilayer oxygen barrier film according to any one of claims 1 to 6, wherein the oxygen barrier layer contains no crosslinking agent and / or adhesion promoter, and optionally contains neither a crosslinking agent nor an adhesion promoter.

8. The primer layer contains at least about 0.01 g / m² ２ A multilayer oxygen barrier film according to any one of claims 1 to 7, having a coating weight of .

9. The primer layer has a coat weight of from about 0.01 g / m ２ to about 5 g / m ２ from about 0.01 g / m ２ to about 2 g / m ２ from about 0.01 g / m ２ to about 1 g / m ２ from about 0.01 g / m ２ to about 0.5 g / m ２ from about 0.01 g / m ２ to about 0.1 g / m ２ or from about 0.01 g / m ２ to about 0.05 g / m ２ and is a multilayer oxygen barrier film according to any one of claims 1 to 8.

10. The multilayer oxygen barrier film according to any one of claims 1 to 9, wherein the primer layer is adjacent to the oxygen barrier layer.

11. The multilayer oxygen barrier film according to any one of claims 1 to 10, wherein the primer layer is located between the base film layer and the oxygen barrier layer.

12. The multilayer oxygen barrier film according to any one of claims 1 to 11, wherein the base film layer comprises polypropylene.

13. The multilayer oxygen barrier film according to any one of claims 1 to 12, wherein the base film layer comprises biaxially oriented polypropylene.

14. The aforementioned film, A sealable layer; Printable layer; Metallized layer; and / or Functional and / or aesthetic coatings A multilayer oxygen barrier film according to any one of claims 1 to 13, comprising one or more additional layers selected from.

15. A multilayer oxygen barrier film according to any one of claims 1 to 14, wherein the film does not contain a metallized layer.

16. A multilayer oxygen barrier film according to any one of claims 1 to 15, wherein the thickness of the multilayer barrier film is approximately 10 μm to approximately 240 μm.

17. The film, when measured according to ASTM D3985, has a thickness of approximately 5 cm at 0% relative humidity. ３ / m ２ / Less than 24 hours, or about 3 cm ３ / m ２ / Less than 24 hours, or about 1 cm ３ / m ２ / Less than 24 hours, or about 0.5 cm ３ / m ２ A multilayer oxygen barrier film according to any one of claims 1 to 16, exhibiting an oxygen permeability of less than 24 hours.

18. The film, when measured according to ASTM F1927-14, is approximately 20 cm² at 50% relative humidity. ３ / m ２ / Less than 24 hours, or about 10 cm ３ / m ２ / Less than 24 hours, or about 5 cm ３ / m ２ / Less than 24 hours, or about 3 cm ３ / m ２ A multilayer oxygen barrier film according to any one of claims 1 to 17, exhibiting an oxygen permeability of less than 24 hours.

19. Use of the multilayer oxygen barrier film according to any one of claims 1 to 18 as a packaging film.

20. A package formed at least partially from a multilayer barrier film according to any one of claims 1 to 18.

21. An article enclosed or packaged in a material comprising a multilayer oxygen barrier film according to any one of claims 1 to 18.

22. A method for manufacturing a multilayer oxygen barrier film, a. At least about 0.005 g / m ２ The steps include: applying a primer layer containing polyethyleneimine to at least one surface of a base film layer containing polyolefin at a coat weight, and b. The step of coating the primer layer with an oxygen barrier layer containing a vinyl alcohol-based polymer. A method that includes this.

23. The method according to claim 22, wherein the vinyl alcohol-based polymer contains polyvinyl alcohol.

24. The method according to claim 22 or 23, further comprising the step of corona-treating the surface of the base film to which the primer layer is applied, prior to step a.

25. The method according to any one of claims 22 to 24, wherein step a. and / or step b. are performed using standard coating techniques, optionally using reverse gravure.

26. The method according to any one of claims 22 to 25, wherein step b comprises coating the primer layer with a vinyl alcohol-based polymer solution, and subsequently drying the layer.

27. The method according to claim 26, wherein the vinyl alcohol-based polymer solution has a pH of about 11 or less, about 10 or less, about 9 or less, about 8 or less, about 7 or less, about 6 or less, about 5 or less, about 4 or less, or about 3 or less.

28. Use of a primer layer containing polyethyleneimine to reduce the oxygen permeability of a multilayer oxygen barrier film.

29. The primer layer contains at least about 0.005 g / m² ２ The use according to claim 28, having a coat weight of

30. The use according to claim 28 or 29, wherein the multilayer oxygen barrier film further comprises an oxygen barrier layer containing a vinyl alcohol-based polymer, optionally polyvinyl alcohol.

31. The use according to any one of claims 28 to 30, wherein the multilayer oxygen barrier film optionally further comprises a base film layer containing biaxially oriented polypropylene.

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