Sealing film having oxygen absorption effect, preparation method therefor, use thereof, and package

Abstract

A sealing film having an oxygen absorption effect, a preparation method therefor, a use thereof, and a package. The sealing film (10) comprises a film body (12) and a functional coating (14), the functional coating containing a noble metal capable of catalyzing a hydrogen-oxygen reaction, and the functional coating having at least a region satisfying E=c×h, E≥150, h≥2, and c≥50, h and c being a thickness value of the region and a concentration value of the noble metal, respectively. The functional coating contains a noble metal capable of catalyzing a hydrogen-oxygen reaction, which facilitates reduction of oxygen content. The coating is also capable of curing generated water, and the generated water can open a gas migration channel in the functional coating, thus further accelerating the removal of oxygen. By embodying the noble metal in the form of a coating, the risk of migration and falling off of the noble metal during use or transportation can also be reduced or avoided.

Description

A sealing film with oxygen absorption effect, its preparation method and application, and packaging.

[0001] Relevant publicly available cross-references

[0002] This disclosure claims priority to Chinese Patent 2024109752924, filed on July 19, 2024, entitled “A sealing film with oxygen absorption effect and its preparation method and application and packaging”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of food packaging technology, and more specifically, to a sealing film with oxygen absorption effect, its preparation method and application, and packaging. Background Technology

[0004] Traditional milk powder filling processes are limited and cannot completely remove oxygen from the cans, typically reducing the oxygen content to around 2% to 3%. The presence of oxygen is detrimental to oxygen-sensitive ingredients, easily leading to oxidation and deterioration of product quality. Furthermore, milk powder is not only sensitive to oxygen but also to water, which can manifest as clumping upon contact with water.

[0005] In view of this, this disclosure is hereby made. Summary of the Invention

[0006] The purpose of this disclosure is to provide a sealing film with oxygen absorption effect, its preparation method, application, and packaging, which can solve or improve the above-mentioned technical problems.

[0007] This disclosure can be implemented as follows:

[0008] In a first aspect, this disclosure provides a sealing membrane, which includes a membrane body and a functional coating disposed on the surface of the membrane body; the functional coating contains a noble metal capable of catalyzing a hydrogen-oxygen reaction; the functional coating has at least a region satisfying E = c × h, E ≥ 150, h ≥ 2, c ≥ 50; wherein, in μm, the thickness of the region is h; and in ppm, the concentration of the noble metal in the region is c.

[0009] In an optional embodiment, the sealing film is used to absorb oxygen by consuming the oxygen inside the sealed packaging in the presence of hydrogen.

[0010] Secondly, this disclosure provides a sealing membrane with oxygen absorption effect, which includes a membrane body and a functional coating disposed on the surface of the membrane body; the functional coating contains a noble metal capable of catalyzing the hydrogen-oxygen reaction; the functional coating has at least a region satisfying E=c×h, E≥150, h≥2, c≥50; wherein, in μm, the thickness of the region is h; and in ppm, the concentration of the noble metal in the region is c.

[0011] This sealing film is used to consume the oxygen inside the sealed packaging in the presence of hydrogen.

[0012] In an optional embodiment, the sealing film in any of the above embodiments, under the condition that the packaging contains both hydrogen and oxygen, uses the catalytic effect of precious metals to cause a hydrogen-oxygen reaction between the hydrogen and oxygen to consume the oxygen in the packaging.

[0013] In an optional embodiment, the thickness of the functional coating is h in μm; the concentration of the noble metal in the functional coating is c in ppm, and c and h satisfy: E=c×h, E≥150, h≥2, c≥50.

[0014] In an optional implementation, the precious metal includes at least one of Pd and Pt.

[0015] In an optional embodiment, the particle size of the noble metal is 10 nm to 20 nm.

[0016] In an optional embodiment, the concentration of the precious metal in the functional coating is at the ppm level.

[0017] In an optional embodiment, the thickness of the functional coating is 2 μm to 10 μm.

[0018] In an optional embodiment, the thickness of the functional coating is 5 μm to 7 μm.

[0019] In an optional embodiment, the sealing film further includes a first heat-sealing layer disposed on the surface of the film body, and a functional coating disposed on the side of the first heat-sealing layer away from the film body.

[0020] In an optional embodiment, the sealing film further includes a second heat-sealing layer disposed on the side of the functional coating away from the first heat-sealing layer.

[0021] In an optional embodiment, the sealing film further includes an additional layer disposed on the surface of the film body on the side opposite to the first heat-sealing layer.

[0022] In an optional implementation, the additional layer includes a clear coat.

[0023] In an optional embodiment, the membrane body comprises aluminum foil or plastic film.

[0024] In an optional implementation, the total thickness of the first heat-sealing layer, the functional coating, and the second heat-sealing layer does not exceed 20 μm.

[0025] Thirdly, this disclosure provides a method for preparing a sealing film as described in the foregoing embodiments, comprising the following steps: setting a structural layer on the surface of the film body at a preset position.

[0026] In an optional embodiment, the preparation slurry for each structural layer is applied to a predetermined location and then dried.

[0027] In an optional embodiment, the slurry for preparing the functional coating includes a noble metal dispersion and an adhesive.

[0028] In an optional embodiment, the mass ratio of the precious metal dispersion to the adhesive is 80:20 to 90:10.

[0029] In an optional embodiment, the concentration of the precious metal in the precious metal dispersion is 500 ppm to 10000 ppm.

[0030] In an optional embodiment, the precious metal dispersion is an organic solvent-based precious metal dispersion or an aqueous precious metal dispersion, wherein the carrier in the organic solvent-based precious metal dispersion is mainly an organic reagent, and the carrier in the aqueous precious metal dispersion is mainly water.

[0031] In an optional embodiment, the coating amount of the functional coating is 2 g / m². 2 ~10g / m 2 .

[0032] In an optional embodiment, the coating speed of the functional coating is 30 m / min to 100 m / min.

[0033] In an optional embodiment, the drying temperature of the functional coating is 80°C to 130°C.

[0034] Fourthly, this disclosure provides an application of a sealing film as described in any of the foregoing embodiments, the sealing film being used to consume oxygen within a package containing the sealing film.

[0035] Fifthly, this disclosure provides a package comprising a package body, the sealing end of which has a sealing film as described in the foregoing embodiments.

[0036] In a sixth aspect, this disclosure provides a package comprising a package body, the package body being composed of the sealing film of the foregoing embodiments.

[0037] In an optional embodiment, the packaging body contains residual oxygen and a mixture of hydrogen and inert gases.

[0038] In an optional implementation, after encapsulation, the hydrogen content inside the package is at least twice the residual oxygen content inside the package.

[0039] In an optional implementation, the packaging body may be made of a metal-containing material.

[0040] In an optional implementation, the metallic material includes materials containing iron and / or aluminum.

[0041] In an optional embodiment, the packaging body also includes oxygen-sensitive contents.

[0042] In an optional implementation, the contents include dairy products.

[0043] In an optional implementation, the contents include milk powder and / or protein powder.

[0044] The beneficial effects of this disclosure include:

[0045] The functional coating of the sealing film disclosed herein contains a noble metal capable of catalyzing the hydrogen-oxygen reaction, thus reducing oxygen content. This functional coating can also solidify the generated water, which opens gas migration channels within the functional coating, further accelerating oxygen removal. The functional coating has at least regions satisfying E = c × h, E ≥ 150, h ≥ 2, and c ≥ 50, enabling basic removal of oxygen and water. By incorporating the noble metal capable of catalyzing the hydrogen-oxygen reaction in the form of a coating, the risk of migration and shedding of the noble metal during shelf life can be reduced or avoided. The sealing film containing this functional coating has oxygen and water absorption effects and can be further used in various types of packaging, such as food packaging for milk powder. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 is a schematic diagram of the first structure of the sealing film provided in this disclosure;

[0048] Figure 2 is a schematic diagram of the second structure of the sealing film provided in this disclosure;

[0049] Figure 3 shows the results of residual oxygen content for the nine experimental groups in Example 1 of this disclosure at different numbers of days;

[0050] Figure 4 shows the results of residual oxygen content for the experimental groups "20-5", "15-5" and "10-5" in Figure 3 for different number of days;

[0051] Figure 5 shows the results of residual oxygen content for different number of days in the "15-10" experimental group in Figure 3.

[0052] Figure 6 shows the results of residual oxygen content for the experimental groups "20-7", "15-7" and "10-7" in Figure 3 for different number of days;

[0053] Figure 7 shows the results of residual oxygen content for the experimental groups “15-5”, “15-7”, and “15-10” in Figure 3 for different number of days.

[0054] Icons: 10-Sealing film; 11-Additional layer; 12-Film body; 13-First heat-sealing layer; 14-Functional coating; 15-Second heat-sealing layer. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions in the embodiments of this disclosure will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0056] The following provides a detailed description of the sealing film, its preparation method, application, and packaging provided in this disclosure.

[0057] This disclosure proposes a sealing film 10, which is not necessarily a film in the absolute sense. Specifically, it can be a layered form such as a coating, or a film form, etc.

[0058] Referring to Figure 1, the sealing film 10 includes a film body 12 and a functional coating 14, which is disposed on the surface of the film body 12.

[0059] The membrane body 12 can serve as a support layer, providing strength and barrier properties for the sealing membrane 10. In some embodiments, the membrane body 12 may include aluminum foil or plastic film, etc. Aluminum foil, in particular, has the characteristics of high strength and complete barrier properties.

[0060] In some embodiments, the thickness of the membrane body 12 is 20 μm to 200 μm, such as 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm or 200 μm.

[0061] For example, when aluminum foil is used as the membrane body 12, its thickness can be 60 μm to 90 μm; when plastic film or the like is used as the membrane body 12, its thickness can be greater than or equal to 150 μm. In some embodiments, the functional coating 14 can be directly disposed on the surface of the membrane body 12 or indirectly disposed on the surface of the membrane body 12. "Indirectly disposed" can be understood as meaning that other structures are provided between the membrane body 12 and the functional coating 14.

[0062] In the technical solution disclosed herein, the functional coating 14 contains a noble metal capable of catalyzing the hydrogen-oxygen reaction; the functional coating 14 has at least a region satisfying E=c×h, E≥150, h≥2, c≥50; wherein, in μm, the thickness of the region is h; and in ppm, the concentration of the noble metal in the region is c.

[0063] In some embodiments, the noble metal in the functional coating 14 is uniformly distributed. Accordingly, the thickness of the functional coating 14 is h in μm and the concentration of the noble metal in the functional coating 14 is c in ppm. c and h satisfy: E = c × h, E ≥ 150, h ≥ 2, c ≥ 50.

[0064] In other embodiments, the noble metal in the functional coating 14 is non-uniformly distributed, for example, it is not uniformly distributed in the thickness direction and / or horizontal plane. In this case, it is sufficient as long as there is a region in the entire functional coating 14 that satisfies E = c × h, E ≥ 150, h ≥ 2, and c ≥ 50 (the thickness of this region is h in μm; the concentration of the noble metal in this region is c in ppm). It should be noted that the number of regions in the functional coating 14 that satisfy the above conditions can be only one, or it can be two or more.

[0065] The aforementioned sealing film 10 is used to absorb oxygen by consuming the oxygen inside the packaging containing the sealing film 10 in the presence of hydrogen. Specifically, when the packaging contains both hydrogen and oxygen, the sealing film 10 uses the catalytic effect of a precious metal to cause a hydrogen-oxygen reaction between the hydrogen and oxygen, thereby consuming the oxygen inside the packaging.

[0066] The aforementioned functional coating 14 contains a noble metal capable of catalyzing the hydrogen-oxygen reaction, thus reducing oxygen content. By defining the coordination relationship between hydrogen and oxygen (h and c), the functional coating 14 can solidify the water generated during the hydrogen-oxygen reaction. Furthermore, it ensures that the generated water can open gas migration channels within the functional coating 14, accelerating the diffusion of hydrogen and oxygen from the container into the coating 14, further accelerating oxygen consumption and removal. The functional coating 14, satisfying the above formula, can achieve basic removal of oxygen and water. In addition, by incorporating the noble metal capable of catalyzing the hydrogen-oxygen reaction in the form of a coating, the risk of migration and detachment of the noble metal during shelf life can be reduced or avoided.

[0067] By way of example, the aforementioned precious metals may include, but are not limited to, at least one of Pd and Pt. For cost considerations, Pd is preferred.

[0068] In some embodiments, the precious metal is in particulate form; in other embodiments, the precious metal is in non-particulate form.

[0069] In some embodiments, the size of the precious metal is in the nanometer to micrometer range. In some more typical embodiments, the precious metal is in particulate form with a particle size of 10 nm to 20 nm, such as 10 nm, 12 nm, 15 nm, 18 nm, or 20 nm.

[0070] In some embodiments, the concentration of precious metals in the functional coating 14 is at the ppm level, which can save costs while achieving its function and reduce or avoid potential food safety risks. For example, the concentration of precious metals in the functional coating 14 can be 200ppm to 500ppm, such as 200ppm, 250ppm, 300ppm, 350ppm, 400ppm, 450ppm, or 500ppm.

[0071] In some embodiments, the thickness of the functional coating 14 is 2 μm to 10 μm, such as 2 μm, 4 μm, 6 μm, 8 μm, or 10 μm. In some preferred embodiments, the thickness of the functional coating 14 is 5 μm to 7 μm, such as 5 μm, 5.5 μm, 6 μm, 6.5 μm, or 7 μm.

[0072] The functional coating 14 can be a single layer or multiple layers, with a total thickness of ≥2μm. When the functional coating 14 has multiple layers, it can be a multi-layer palladium coating, a multi-layer platinum coating, or an alternating combination of palladium and platinum coatings. Furthermore, the same functional coating 14 can contain only palladium, only platinum, or both palladium and platinum.

[0073] In some embodiments, the functional coating 14, in addition to having an oxygen absorption function, can also provide a certain heat-sealing effect. Under these conditions, the functional coating 14 also contains components with heat-sealing properties.

[0074] In some embodiments, the sealing film 10 further includes a first heat-sealing layer 13, which is disposed on the surface of the film body 12, and a functional coating 14 is disposed on the side of the first heat-sealing layer 13 away from the film body 12.

[0075] The first heat-sealing layer 13 is mainly used to provide a heat-sealing effect. The thickness of the first heat-sealing layer 13 can be ≤15μm, such as 15μm, 12μm, 10μm, 8μm, 5μm or 2μm, etc.

[0076] In some optional embodiments, as shown in FIG2, the sealing film 10 may further include a second heat-sealing layer 15, which is disposed on the surface of the functional coating 14 away from the first heat-sealing layer 13. That is, the second heat-sealing layer 15 is an optional layer, which may or may not be provided depending on actual needs.

[0077] The second heat-sealing layer 15 can provide heat sealing while also isolating the contents of the packaging from the functional coating 14, making it suitable for situations where the contents of the packaging have strong permeability.

[0078] For example, the thickness of the second heat-sealing layer 15 can be ≤15μm, such as 15μm, 12μm, 10μm, 8μm, 5μm or 2μm, etc.

[0079] The heat-sealing materials for the first heat-sealing layer 13 and the second heat-sealing layer 15 can be set with reference to existing technologies; any material capable of heat sealing is acceptable. It should be noted that when the packaging is food packaging, the heat-sealing material must also meet the requirements of the food industry.

[0080] Furthermore, the sealing film 10 may also include an additional layer 11, which is disposed on the surface of the film body 12 on the side opposite to the first heat-sealing layer 13.

[0081] By way of example, the additional layer 11 may, by way of example but not by way of limitation, include a varnish coating that can protect the surface of the film body 12. In addition, it is not excluded that the additional layer 11 may be provided with other functions as needed.

[0082] For example, the thickness of the additional layer 11 can be 2μm to 8μm, such as 2μm, 3μm, 4μm, 5μm, 6μm, 7μm or 8μm.

[0083] In some specific embodiments, the sealing film 10 may include an additional layer 11, a film body 12, a first heat-sealing layer 13, a functional coating 14, and a second heat-sealing layer 15, arranged from top to bottom. In other embodiments, in addition to the optional provisioning and replacement of the additional layer 11 and the second heat-sealing layer 15, it is also possible to add other coatings between the layers.

[0084] In some embodiments, the total thickness of the first heat-sealing layer 13, the functional coating 14, and the second heat-sealing layer 15 does not exceed 20 μm, such as 20 μm, 18 μm, 15 μm, 12 μm, 10 μm, 8 μm, or 5 μm.

[0085] The aforementioned sealing film 10 not only facilitates oxygen removal and water absorption, but also ensures good adhesive strength between the sealing film 10 and the packaging body. Furthermore, the sealing film 10 can be a disposable film, meaning it is not reused after being torn open, thus preventing excessive contact between the contents and the sealing film 10.

[0086] In addition, this disclosure also provides a method for preparing the above-mentioned sealing film 10, including the following steps: setting each structural layer on the surface of the film body 12 at a preset position.

[0087] For example, the preparation slurry for each structural layer is applied to a predetermined position, dried, and then heat-sealed as needed.

[0088] The slurry for preparing the functional coating 14 includes a precious metal dispersion and an adhesive. The adhesive may, by way of example but not by way of limitation, be an acrylic adhesive and / or a polyester adhesive. Depending on the adhesive system, it may also include water-based or oil-based adhesives. In some exemplary embodiments, the adhesive used to prepare the slurry may be, for example, Michelman Prime 498345N, Henkel LOCTITE LIOFOL HS1147, and / or Guangzhou Hongtai 13084, etc. The specific adhesive used can be selected according to actual needs.

[0089] In some embodiments, the solid content of the prepared slurry can be 30% to 45%, such as 30%, 32%, 34%, 36%, 40%, 42%, or 45%, or other values ​​within the range of 30% to 45%.

[0090] In some embodiments, the mass ratio of the precious metal dispersion to the adhesive can be from 80:20 to 90:10, such as 80:20, 81:19, 82:18, 83:17, 84:16, 85:15, 86:14, 87:13, 88:12, 89:11 or 90:10, or any other value within the range of 80:20 to 90:10.

[0091] In some embodiments, the concentration of the precious metal in the precious metal dispersion can be 500ppm to 10000ppm, such as 500ppm, 1000ppm, 2000ppm, 4000ppm, 6000ppm, 8000ppm or 10000ppm, or other values ​​within the range of 500ppm to 10000ppm.

[0092] The aforementioned precious metal dispersions can be either organic solvent-based or aqueous precious metal dispersions. In organic solvent-based precious metal dispersions, the carrier is primarily an organic reagent (such as ethyl acetate), while in aqueous precious metal dispersions, the carrier is primarily water.

[0093] In some embodiments, the aqueous precious metal dispersion is obtained by mixing water and a precious metal. The concentration of the precious metal in the aqueous precious metal dispersion is 500 ppm to 10000 ppm. Examples, but not limited to, adhesives used with this aqueous precious metal dispersion may include Michelman Prime 498345N, etc.

[0094] In some embodiments, the organic solvent-based precious metal dispersion is obtained by mixing ethyl acetate and a precious metal. The concentration of the precious metal in the organic solvent-based precious metal dispersion is 500 ppm to 10000 ppm. Exemplary, but not limited, adhesives used with this organic solvent-based precious metal dispersion may include Henkel LOCTITE LIOFOL HS1147 and / or Guangzhou Hongtai 13084, etc.

[0095] In some embodiments, the coating weight of the functional coating 14 can be 2 g / m² on a wet weight basis. 2 ~10g / m 2 such as 2g / m 2 3g / m 2 4g / m 2 5g / m 2 6g / m 2 7g / m 2 8g / m 2 9g / m 2 or 10g / m 2 etc., can also be 2g / m 2 ~10g / m 2 Any other value within the range. The functional coating 14 can be applied only once, or twice or more, as long as the total coating amount is controlled within the above range. In some embodiments, it can be 1 g / m³. 2 The coating is applied to a thickness of 1 μm. In other embodiments, the relationship between the coating amount and the thickness can be adjusted appropriately according to the actual situation.

[0096] In some embodiments, the coating speed of the functional coating 14 can be 30 m / min to 100 m / min, such as 30 m / min, 40 m / min, 50 m / min, 60 m / min, 70 m / min, 80 m / min, 90 m / min or 100 m / min, or any other value in the range of 30 m / min to 100 m / min.

[0097] The above coating can be performed using an anilox roller, but other coating equipment may also be used.

[0098] In some embodiments, the drying temperature of the functional coating 14 can be 80°C to 130°C, such as 80°C, 90°C, 100°C, 110°C, 120°C or 130°C, or any other value within the range of 80°C to 130°C.

[0099] In some other ways, the functional coating 14 may be prepared without adhesives. For example, it can be prepared by dispersing precious metals in PP or PE and using a coating method instead of a film coating, so that the functional coating 14 adheres to the surface of the membrane body 12.

[0100] The hydrogen-oxygen reaction mentioned in this disclosure takes place at the catalyst interface. The water generated can be cured by the coating system. On the one hand, this prevents the generated water molecules from escaping into the powder and causing agglomeration. On the other hand, water, as a plasticizer, can open the gas migration channels in the coating, further accelerating the removal of oxygen. However, if the precious metal is not represented by a coating but used alone, it not only poses a risk of foreign matter, but the water generated after the reaction of oxygen and hydrogen cannot be discharged, which can easily cause water-sensitive contents to clump together.

[0101] It should be noted that the preparation processes and conditions of other structural layers involved in this disclosure can be referred to the relevant prior art, and will not be elaborated or limited here. In addition, this disclosure also provides an application of the above-mentioned sealing film 10, which is used to consume oxygen in the packaging containing the sealing film 10, and can further play the role of absorbing oxygen and water.

[0102] Accordingly, this disclosure also provides a package comprising a package body.

[0103] In some embodiments, the sealing end of the packaging body has the aforementioned sealing film 10.

[0104] In other embodiments, the packaging body is composed of the sealing film 10 described above.

[0105] The aforementioned packaging body contains residual oxygen and an oxygen-free and anhydrous gas mixture including hydrogen and an inert gas (the inert gas may include, but is not limited to, nitrogen). Specifically, after sealing, the packaging ensures that the aforementioned gas mixture is present inside. Hydrogen, as a reactive gas, is used to consume the residual oxygen within the packaging. Oxygen that may be present within the packaging body reacts with the hydrogen within the packaging body through a hydrogen-oxygen reaction under the catalytic action of the noble metal in the functional coating 14, thereby effectively removing oxygen from the packaging body.

[0106] In some implementations, after encapsulation, the hydrogen content inside the package is at least twice the amount of residual oxygen inside the package, so that all the residual oxygen can react.

[0107] In some implementations, after encapsulation, the residual oxygen content inside the packaging does not exceed 3% (e.g., 2% to 3%). Correspondingly, after encapsulation, the hydrogen content inside the packaging can be below 10%, but must meet the minimum theoretical requirement for the residual oxygen to be completely reacted. For example, after encapsulation, the hydrogen content inside the packaging can be 2% to 10%.

[0108] In some embodiments, the packaging body is made of a metal-containing material, such as a material containing iron and / or aluminum. Alternatively, it may be made of other materials, such as PET, depending on the product requirements. In some special embodiments, the packaging body may also be a paper-based packaging material containing metal.

[0109] In some embodiments, the packaging body also includes oxygen-sensitive contents. These contents may, by way of example but not in a limiting sense, include dairy products, such as milk powder and / or protein powder.

[0110] In some typical implementations, the packaging is in the form of milk powder cans and / or protein powder cans.

[0111] It should be noted that traditional milk powder filling processes are limited and cannot completely remove oxygen from the can, maintaining it at around 2% to 3%, which is detrimental to oxygen-sensitive formula ingredients. Some milk powders use oxygen removal bags (such as iron powder) for deoxygenation, but this poses a risk of foreign matter.

[0112] By applying the sealing film 10 containing the functional coating 14 provided in this disclosure to the sealed end of the milk powder can, on the one hand, under the catalytic effect of the precious metal in the functional coating 14, hydrogen and oxygen inside the milk powder can react to produce water, thereby consuming the oxygen inside the can and maintaining the can in an oxygen-free state during transportation or shelf life (e.g., achieving an oxygen-free state within 15 days after sealing); on the other hand, the functional coating 14 can absorb the generated water, preventing milk powder from clumping. Furthermore, the functional coating 14 can also form oxygen channels, accelerating oxygen consumption.

[0113] It should be noted that the above-mentioned "anaerobic state" refers to the oxygen content in the milk powder can not exceeding 1% (volume percentage), preferably not exceeding 0.5%, more preferably not exceeding 0.1%, and even more preferably 0%.

[0114] The features and performance of this disclosure will be further described in detail below with reference to embodiments.

[0115] Example 1

[0116] This embodiment provides a sealing film 10, as shown in FIG1. ​​From top to bottom, the sealing film 10 includes an additional layer 11, a film body 12, a first heat-sealing layer 13, and a functional coating 14 stacked sequentially.

[0117] The additional layer 11 is a varnish coating, and the film body 12 is an aluminum foil. The total thickness of the sealing film 10 is 105.5 μm, the thickness of the additional layer 11 is 5 μm, the thickness of the film body 12 is 90 μm, and the thickness of the first heat-sealing layer 13 is 8 μm.

[0118] The aforementioned functional coating 14 contains uniformly distributed Pd particles. The concentration of Pd particles in the functional coating 14 is 360 ppm, and the particle size of the Pd particles is 10 nm to 20 nm. The thickness of the functional coating 14 is 2.5 μm. Accordingly, E = c × h = 360 × 2.5 = 900.

[0119] Example 2

[0120] This embodiment provides a sealing film 10, which differs from Embodiment 1 in that: the concentration of Pd particles in the functional coating 14 is 200 ppm, and the particle size of the Pd particles is 10 nm to 20 nm; the thickness of the functional coating 14 is 5 μm. Accordingly, E = c × h = 200 × 5 = 1000.

[0121] Example 3

[0122] This embodiment provides a sealing film 10, which differs from Embodiment 1 in that: the concentration of Pd particles in the functional coating 14 is 500 ppm, and the particle size of the Pd particles is 10 nm to 20 nm; the thickness of the functional coating 14 is 7 μm. Accordingly, E = c × h = 500 × 7 = 3500.

[0123] Example 4

[0124] This embodiment provides a sealing film 10, which differs from Embodiment 1 in that: the concentration of Pd particles in the functional coating 14 is 600 ppm, and the particle size of the Pd particles is 10 nm to 20 nm; the thickness of the functional coating 14 is 10 μm. Accordingly, E = c × h = 600 × 10 = 6000.

[0125] Example 5

[0126] This embodiment provides a sealing film 10, which differs from Embodiment 1 in that: the concentration of Pd particles in the functional coating 14 is 50 ppm, and the particle size of the Pd particles is 10 nm to 20 nm; the thickness of the functional coating 14 is 3 μm. Accordingly, E = c × h = 50 × 3 = 150.

[0127] Example 6

[0128] This embodiment provides a sealing film 10, which differs from Embodiment 1 in that: the concentration of Pd particles in the functional coating 14 is 75 ppm, and the particle size of the Pd particles is 10 nm to 20 nm; the thickness of the functional coating 14 is 2 μm. Accordingly, E = c × h = 75 × 2 = 150.

[0129] Example 7

[0130] As shown in Figure 2, the difference between this embodiment and embodiment 1 is that the lower surface of the functional coating 14 is further provided with a second heat-sealing layer 15, and the thickness of the second heat-sealing layer 15 is 4μm.

[0131] Example 8

[0132] The difference between this embodiment and Embodiment 1 is that it does not include the additional layer 11.

[0133] Example 9

[0134] This embodiment provides a method for preparing a functional coating 14, including:

[0135] S1: Pd particles and water are mixed to obtain an aqueous precious metal dispersion with a Pd particle concentration of 2000 ppm;

[0136] S2: The aqueous precious metal dispersion and the adhesive (Michelman Prime 498345N) were mixed at a mass ratio of 82:18 to obtain a slurry with a solid content of 45%.

[0137] S3: The prepared slurry is coated onto the substrate surface (aluminum foil) twice, with a total coating weight of 7 g / m². 2 The coating speed is 50 m / min;

[0138] S4: After coating, dry at 100℃.

[0139] Example 10

[0140] This embodiment provides a method for preparing a functional coating 14, including:

[0141] S1: Pd particles and water are mixed to obtain an organic solvent-based noble metal dispersion with a Pd particle concentration of 2000 ppm.

[0142] S2: Mix the organic solvent-based precious metal dispersion with the adhesive (Guangzhou Hongtai 13084) at a mass ratio of 80:20 to obtain a slurry with a solid content of about 30%.

[0143] S3: The prepared slurry is coated onto the substrate surface (aluminum foil) twice, with a total coating weight of 10 g / m². 2 The coating speed is 50 m / min;

[0144] S4: After coating, dry at 80℃.

[0145] Example 11

[0146] This embodiment provides a method for preparing a functional coating 14, including:

[0147] S1: Pd particles and ethyl acetate were mixed to obtain an organic solvent-based noble metal dispersion with a Pd particle concentration of 2000 ppm.

[0148] S2: Mix the organic solvent-based precious metal dispersion with the adhesive (Henkel LOCTITE LIOFOL HS 1147) at a mass ratio of 90:10 to obtain a slurry with a solid content of approximately 40%.

[0149] S3: The prepared slurry is coated onto the substrate surface (aluminum foil) twice, with a total coating weight of 5 g / m². 2 The coating speed is 100 m / min;

[0150] S4: After coating, dry at 130℃.

[0151] Example 12

[0152] This embodiment provides a milk powder can, which includes an iron can body. The sealed end of the iron can body has a sealing film 10 provided in Embodiment 1. The functional coating in the sealing film can be prepared according to the method of Embodiment 9. The headspace of the can body is filled with nitrogen gas containing hydrogen. The hydrogen content is twice the residual oxygen content in the can body.

[0153] Experimental Example 1

[0154] Taking Example 12 as an example, the functional coating 14 was adjusted to form different experimental groups. The adjustment methods included adjusting the concentration of Pd in ​​the prepared slurry and the coating amount on a wet weight basis. Different coating amounts corresponded to different thicknesses of the functional coating. For a specific experimental group, the functional coating met the minimum thickness required for effectiveness when it reached the critical basis weight. After packaging, the relationship between the oxygen content in the milk powder cans of each experimental group and the number of days of storage was tested, and the results are shown in Figure 3.

[0155] Referring to Figure 3, the experiment was divided into nine groups, designated as "20-5", "20-7", "20-10", "15-5", "15-7", "15-10", "10-5", "10-5", and "10-10" respectively. Taking "20-5" as an example, "20" refers to the mass percentage of Pd dispersion in the prepared slurry (%), and "5" refers to the coating weight on a wet weight basis (g / m²). 2 In Figure 3, the horizontal axis represents the number of days, and the vertical axis represents the oxygen content, in percentages.

[0156] As can be seen from Figure 3, the results of some experimental groups were not ideal, while the remaining experimental groups were able to remove residual oxygen.

[0157] ① Referring to Figure 4, which shows the test results of the three experimental groups "20-5", "15-5", and "10-5" in Figure 3, the solid content of the prepared slurry in these three experimental groups was 36%, and the coating weight on a wet weight basis was 5 g / m². 2The concentration of Pd particles in the dispersion was 2000 ppm in all groups. Specifically, the mass ratio of adhesive to dispersion in group "20-5" was 80:20 (meaning the mass percentage of Pd dispersion in the prepared slurry was 20%, and the corresponding Pd concentration in the prepared slurry was 400 ppm); the mass ratio of adhesive to dispersion in group "15-5" was 85:15 (meaning the mass percentage of Pd dispersion in the prepared slurry was 15%, and the corresponding Pd concentration in the prepared slurry was 300 ppm); and the mass ratio of adhesive to dispersion in group "10-5" was 90:10 (meaning the mass percentage of Pd dispersion in the prepared slurry was 10%, and the corresponding Pd concentration in the prepared slurry was 200 ppm).

[0158] As can be seen from Figure 4, the coating weight on a wet weight basis is 5 g / m². 2 Under these conditions, regardless of whether the concentration of Pd in ​​the slurry is 400ppm, 300ppm, or 200ppm, the palladium content in the corresponding functional coating is greater than 50ppm. However, since the critical basis weight for effectiveness is not reached, that is, the thickness of the functional coating is relatively thin, the value of E is <150. Consequently, the oxygen concentration in the milk powder can remains basically constant with the increase of days and does not decrease. The residual oxygen content is still above 1.5%, and the effect of removing residual oxygen is not achieved.

[0159] ② Referring to Figure 5, which shows the test results of experimental group "15-10" in Figure 3, the solid content of the prepared slurry in this experimental group was 36%, and the coating weight on a wet weight basis was 10 g / m². 2 The concentration of Pd particles in the dispersion was 2000 ppm, and the mass ratio of adhesive to dispersion was 85:15 (that is, the mass percentage of Pd dispersion in the prepared slurry was 15%, and the corresponding concentration of Pd in ​​the prepared slurry was 300 ppm). This experimental group satisfied E > 150.

[0160] The result curve of this experimental group, as a typical curve of the onset of effect, shows the characteristics of reverse S, indicating that the onset of effect in this experimental group is divided into three stages.

[0161] Stage I: Mainly controlled by gas adsorption and diffusion. This stage is controlled by the diffusion rate of gas in the dense coating, and the rate of decrease is relatively slow (the slope is small).

[0162] Stage II: In this stage, some hydrogen and oxygen react to produce water, which is locked in the coating and cannot escape into the container space, thus avoiding the problem of milk powder absorbing water and clumping inside the tube; on the other hand, it acts as a plasticizer, destroying the density of the coating and facilitating the subsequent diffusion process of hydrogen and oxygen gas. Therefore, the slope of the curve in this stage is accelerated.

[0163] Stage III: At this point, the concentrations of hydrogen and oxygen in the tank decrease significantly, leading to a decrease in the adsorption and even diffusion concentrations on the coating surface. During this process, the reaction rate is affected by the concentration, and the slope becomes slower.

[0164] ③ Refer to Figure 6, which shows the test results of the experimental groups “20-7”, “15-7” and “10-7” in Figure 3.

[0165] As shown in Figure 6, all three experimental groups effectively removed residual oxygen. Under the premise of effectiveness, for the same coating thickness and different Pd concentrations, the higher the Pd concentration, the faster the oxygen concentration decreased.

[0166] ④ Refer to Figure 7, which shows the test results of experimental groups “15-5”, “15-7” and “15-10” in Figure 3.

[0167] As shown in Figure 7, all three experimental groups effectively removed residual oxygen. At the same concentration, the thicker the film, the faster the oxygen concentration decreased. It should be noted that the oxygen content did not decrease in the "15-5" experimental group because it did not reach the critical point of effectiveness.

[0168] Experimental Example 2

[0169] The TBA value (thiobarbituric acid value) is used to characterize the oxidation problem of products (milk powder) caused by headspace oxygen. Aldehydes, oxidation products of unsaturated fatty acids, can react with thiobarbituric acid (TBA) to form colored compounds.

[0170] Taking Example 12 as an example as the test sample, a control sample was set up. The control sample was made by placing Pd in ​​the form of palladium balls in the milk powder can. The diameter of the palladium balls was 2 mm and the palladium loading was 1000 ppm.

[0171] The headspace oxygen concentration of the control sample was 2.6%, and after 3 months, the TBA value of the control sample was 0.12. Under the same conditions, the TBA value of the test sample in Example 12 of this application was 0.033, which was significantly lower than that of the control sample.

[0172] In summary, the functional coating 14 of the sealing film 10 provided in this disclosure contains a noble metal capable of catalyzing the hydrogen-oxygen reaction, which helps reduce oxygen content. This functional coating 14 can also solidify the generated water, which can open gas migration channels in the functional coating 14, further accelerating oxygen removal. By incorporating the noble metal capable of catalyzing the hydrogen-oxygen reaction in the form of a coating, the risk of migration and shedding of the noble metal during shelf life can be reduced or avoided. The sealing film 10 has both oxygen removal and water absorption effects and can be further used in various types of packaging, such as food packaging for milk powder.

[0173] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure. Industrial applicability

[0174] The sealing film disclosed herein possesses oxygen and water absorption properties and can be used in various packaging applications, such as food packaging seals for milk powder. The functional coating in this sealing film catalyzes the reaction between hydrogen and oxygen, effectively reducing oxygen content. This functional coating also solidifies the generated water, which opens gas migration channels within the functional coating, further accelerating oxygen removal and achieving basic removal of both oxygen and water. Furthermore, by incorporating a precious metal capable of catalyzing the hydrogen-oxygen reaction in the form of a coating, the risk of migration and detachment of precious metals during shelf life can be reduced or avoided. 。

Claims

1. A seal, characterized in that The sealing film comprises a film body and a functional coating layer arranged on the surface of the film body; the functional coating layer contains noble metal capable of catalyzing hydrogen-oxygen reaction; the functional coating layer has at least a region satisfying E=c×h, E≥150, h≥2, c≥50; wherein, h is the thickness of the region in μm; and c is the concentration of the noble metal in the region in ppm.

2. The closure membrane of claim 1, wherein The sealing film is used to consume oxygen in the package containing the sealing film by means of the cooperation of hydrogen to achieve the oxygen absorption effect.

3. A packaging film having an oxygen absorbing effect, characterized by The sealing film comprises a film body and a functional coating layer arranged on the surface of the film body; the functional coating layer contains noble metal capable of catalyzing hydrogen-oxygen reaction; the functional coating layer has at least a region satisfying E=c×h, E≥150, h≥2, c≥50; wherein, h is the thickness of the region in μm; and c is the concentration of the noble metal in the region in ppm. The sealing film is used to consume oxygen in the package containing the sealing film by means of the cooperation of hydrogen.

4. The envelope according to any one of claims 1 to 3, characterized in that The sealing film is used to consume oxygen in the package containing the sealing film by means of the cooperation of hydrogen.

5. The envelope according to any one of claims 1 to 4, characterized in that The sealing film is used to consume oxygen in the package containing the sealing film by means of the cooperation of hydrogen.

6. The closure membrane of claim 5, wherein, The thickness of the functional coating layer is h in μm; and the concentration of the noble metal in the functional coating layer is c in ppm, c and h satisfying E=c×h, E≥150, h≥2, c≥50.

7. The closure membrane of claim 6, wherein The thickness of the functional coating layer is 2 μm-10 μm.

8. The envelope according to any one of claims 1 to 7, characterized in that The thickness of the functional coating layer is 5 μm-7 μm.

9. The lidding membrane according to any one of claims 1 to 8, characterized in that, The noble metal comprises at least one of Pd and Pt.

10. The envelope according to any one of claims 1 to 9, characterized in that The particle size of the noble metal is 10 nm-20 nm.

11. The lidding membrane according to any one of claims 1 to 10, characterized in that, The concentration of the noble metal in the functional coating layer is ppm level.

12. The closure membrane of claim 11, wherein, The sealing film further comprises a first heat sealing layer arranged on the surface of the film body, and the functional coating layer is arranged on the surface of the side of the first heat sealing layer away from the film body.

13. The closure membrane of claim 12, wherein, The sealing film further comprises a second heat sealing layer arranged on the surface of the side of the functional coating layer away from the first heat sealing layer.

14. The closure membrane of claim 13, wherein, The sealing film further comprises an additional layer arranged on the surface of the side of the film body opposite to the first heat sealing layer.

15. The lidding membrane according to any one of claims 1 to 14, characterized in that, The additional layer comprises a varnish coating layer.

16. A closure membrane according to any one of claims 12 to 15, characterised in that The film body comprises aluminum foil or plastic film.

17. A method of producing a closure membrane as claimed in any one of claims 1 to 16, characterised in that, The total thickness of the first heat sealing layer, the functional coating layer and the second heat sealing layer is not more than 20 μm.

18. The method of claim 17, wherein, The method comprises the following steps: arranging a structural layer on the surface of the film body at a preset position.

19. The method of claim 18, wherein, The preparation slurry of each structural layer is coated at the preset position and dried.

20. The method of claim 19, wherein, The preparation slurry of the functional coating layer comprises noble metal dispersion liquid and adhesive.

21. The method of manufacturing according to claim 19 or 20, wherein, The mass ratio of the noble metal dispersion liquid to the adhesive is 80:20-90:

10.

22. The method of any one of claims 19 to 21, wherein the method further comprises, The concentration of noble metal in the noble metal dispersion liquid is 500 ppm-10000 ppm. The noble metal dispersion liquid is organic solvent type noble metal dispersion liquid or water type noble metal dispersion liquid, wherein, the carrier in the organic solvent type noble metal dispersion liquid is mainly organic reagent, and the carrier in the water type noble metal dispersion liquid is mainly water.

23. The method of any one of claims 19 to 22, wherein the method further comprises, The functional coating has a coating amount of 2 g / m 2 ~ 10 g / m 2 .

24. The method of any one of claims 19 to 23, wherein the method further comprises, The functional coating has a coating speed of 30 m / min to 100 m / min.

25. The method of any one of claims 19 to 24, wherein the method further comprises the step of: The functional coating has a drying temperature of 80°C to 130°C.

26. Use of a sealing membrane according to any one of claims 1 to 16, characterized in that The film is used to consume oxygen in a package containing the film.

27. A package characterized in that, The package comprises a package body having a closure end with the film according to any one of claims 1 to 16.

28. A package characterized in that, The package comprises a package body consisting of the film according to any one of claims 1 to 16.

29. The package of claim 27 or 28, wherein, The package body has residual oxygen and a mixed gas comprising hydrogen and an inert gas.

30. The package of claim 29, wherein, After packaging, the hydrogen content in the package is at least twice the residual oxygen content in the package.

31. The package of any one of claims 27-30, wherein, The material of the package body comprises a metal-containing material.

32. The package of claim 31, wherein, The metal-containing material comprises a material containing iron and / or aluminum.

33. The package of any one of claims 29-32, wherein, The package body further comprises an oxygen-sensitive content.

34. The package of claim 33, wherein, The content comprises a dairy product.

35. The package of claim 34, wherein, The content comprises milk powder and / or protein powder.

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