Oxygen scavenging formulations and oxygen scavenging methods

Abstract

The present invention provides an oxygen-scavenging formulation and an oxygen-scavenging method. The oxygen-scavenging formulation of the present invention comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids. The oxygen-scavenging formulation does not require an additional trigger, or heating or light radiation, to trigger the oxygen-scavenging function. The oxygen-scavenging method of the present invention is a method of reducing the oxygen atmosphere in a packaged article.

Description

Technical Field

[0001] This invention relates to an oxygen-removing formulation whose oxygen-removing function does not require an additional triggering agent, or to be activated by heating or light radiation. Specifically, the formulation comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids. Background Technology

[0002] Oxygen-removing encapsulation technology is widely used in the food packaging industry. Most oxygen-sensitive products deteriorate in the presence of oxygen, including food products such as meat and cheese, smoked and processed luncheon meat, and non-food products such as electronic components, pharmaceuticals, and medical products. Limiting oxygen exposure provides a means to maintain and enhance the quality and shelf life of packaged products (specifically in the food industry). Therefore, removing oxygen from packaged products and creating a barrier layer that prevents oxygen permeation during storage is a crucial objective for encapsulation technology.

[0003] Several technologies have been developed to limit the exposure of sensitive packaging materials to oxygen. These technologies include using barrier materials with low oxygen permeability as part of the packaging; including items other than the packaging material that can consume oxygen (via the use of pouches with materials capable of reacting with oxygen); and creating a low-oxygen environment within the packaging (e.g., modified atmospheric encapsulation (MAP) and vacuum encapsulation). While each of these technologies has its place in the industry, it is well recognized that including oxygen scavengers as part of the packaging article is one of the most desirable means of limiting oxygen exposure.

[0004] In the late 1970s, an oxygen-free agent was developed by Mitsubishi Gas Chemical Company, Inc. of Japan. Introduced into commercial applications, these scavengers take the form of oxygen-removing pouches, label stickers, or components within the food packaging materials themselves. The oxygen removal principle relies on the reaction between the scavenger and oxygen. Previously developed scavengers can be distinguished among iron-based, sulfite-based, ascorbate-based, and enzyme-based systems, as well as those capable of oxidizing polyamides and olefinic unsaturated hydrocarbons. These scavengers preferably effectively reduce the oxygen content in the package to at least 0.01% of that in air. This is significantly more effective than MAP, such as vacuum sealing or nitrogen-filling technologies, which can only reduce the oxygen content to 0.3-3%. However, triggering the scavenger to activate the oxidation reaction requires, for example, water, high temperature, or light. Iron-based scavengers are based on the oxidation of metallic iron to ferric hydroxide (II) and ferric hydroxide (III). Except for certain accelerators with a speeding effect, the reaction requires moisture to begin the scavenging process. This generates a triggering mechanism that enables targeted activation. However, such scavengers are only suitable for products with high moisture content. Furthermore, when such powdered scavengers are used on polymer sheets, a general disadvantage is reduced transparency and deterioration of the sheets' mechanical properties. Without a triggering agent or triggering process, oxygen removal cannot be initiated. On the other hand, a triggering agent can be added directly to the encapsulation material to create a self-triggered oxygen removal encapsulation material.

[0005] Conventionally, triggering processes require high temperatures or ultraviolet light to provide a specific amount of energy to activate the deoxygenation function of polymers containing double bonds. For example, US 5911910 A discloses the exposure of encapsulation films made from oxidizable organic compounds (such as unsubstituted or substituted olefinic unsaturated hydrocarbon polymers) to an intensity greater than 100 mJ / cm². 2 The deoxygenation function of oxidizable organic compounds can be triggered by exposure to ultraviolet light and heating to a temperature of 65 to 80°F in a chamber. US 6610215 B discloses a thermally activated deoxygenating formulation comprising oxidizable organic compounds, such as cyclic olefin compounds, for example, ethylene-methylcyclohexene copolymers or ethylene-methyl acrylate / cyclohexene methacrylate terpolymers, and a transition metal catalyst. The deoxygenating formulation can be used in bags and membranes having single-layer or multi-layer structures. The deoxygenation function can be triggered by heating the deoxygenating formulation to a temperature of 75 to 300°C for more than 60 minutes.

[0006] US 7468144 B2 discloses a process for thermally triggering a deoxygenating formulation using a peroxide (such as hydrogen peroxide), the deoxygenating formulation comprising oxidizable organic compounds and transition metals. The process involves wetting the surface of an encapsulated article made from the deoxygenating formulation with a 2% hydrogen peroxide solution; then applying hot air at 70°C to remove excess hydrogen peroxide solution; and finally exposing the article to ultraviolet light to trigger the deoxygenation function. Results show that pretreatment of the encapsulated article with a peroxide enhances the deoxygenation effect caused by oxidizable organic compounds.

[0007] Triggers have also been extensively studied in the art. For example, US 6139770A discloses that the trigger can be a photoinitiator, which includes benzophenone derivatives containing at least two benzophenone moieties, such as tribenzoyltriphenylbenzene and substituted tribenzoyltriphenylbenzene, and that scavenging formulations containing this photoinitiator can be activated by ultraviolet or visible light, electron beam, or thermal triggering with wavelengths ranging from about 200 nm to about 750 nm. US 7153891 B2 discloses that the trigger can be a photoinitiator comprising one or more materials selected from the group consisting of isopropylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 1-chloro-4-propoxythioxanthone, and that scavenging formulations including such photoinitiators can be triggered by a photochemical radiation dose from a germicidal lamp having a main emission wavelength of 254 nm.

[0008] Oxygen scavengers based on polymers containing typical double bonds require activation through exposure to light or heating to high temperatures. However, heating processes are particularly unsuitable for multilayer encapsulation films that have been coated, printed, or heat-sealed, as they are not only time-consuming but also limited to the specific processing temperature range of the encapsulation material. On the other hand, for radiation-triggered oxygen scavengers, food processing plants would need to purchase additional high-intensity UV radiation equipment, resulting in additional financial costs.

[0009] Therefore, although various methods have been developed to trigger the deoxygenation function of packaged products, there is still a need to improve deoxygenation formulations and packaging materials utilizing said deoxygenation formulations. Summary of the Invention

[0010] The present invention provides an improved deoxygenating formulation in which the deoxygenation function does not require an additional triggering agent or to be triggered by heating or light radiation, and an article made from said deoxygenating formulation.

[0011] Therefore, one aspect of the present invention relates to an oxygen-removing formulation comprising an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids.

[0012] Another aspect of the present invention relates to a method for reducing the oxygen atmosphere in an encapsulated article, comprising providing an oxygen-removing agent to the encapsulated article to allow the oxygen-removing agent to come into contact with oxygen and reduce the oxygen atmosphere in the encapsulated article, wherein the oxygen-removing agent comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids.

[0013] Another aspect of the present invention relates to a method for reducing the oxygen atmosphere in an encapsulated article, comprising the steps of: a) exposing an oxygen-removing formulation to UV radiation to trigger oxygen removal, wherein the oxygen-removing formulation comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids; and b) providing the triggered oxygen-removing formulation to the inside of the encapsulated article to allow the oxygen-removing formulation to come into contact with oxygen and reduce the oxygen atmosphere in the encapsulated article.

[0014] Another aspect of the present invention relates to a method for reducing the oxygen atmosphere in an encapsulated article, comprising the steps of: a) exposing a multilayer encapsulation film including an oxygen-removing film to UV radiation to trigger oxygen removal, wherein the oxygen-removing film is composed of an oxygen-removing formulation comprising an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids; and b) sealing the multilayer encapsulation film to form an encapsulation article to allow the oxygen-removing formulation to come into contact with oxygen and reduce the oxygen atmosphere in the encapsulation article. Attached Figure Description

[0015] Figure 1 - (a) and (b) respectively illustrate the changes in the reduction of oxygen concentration and oxygen quantity in an 11 ml gas sealed bottle with respect to the removal time of the blank membrane and the oxygen scavenging membrane containing 1 wt% benzophenone or 1 wt% β-carotene.

[0016] Figure 2 - (a) and (b) illustrate the changes in oxygen concentration and oxygen quantity in an 11 ml gas-sealed bottle with respect to the removal time of an oxygen scavenger membrane containing 1 wt% β-carotene under exposure to UVC light of different energy densities.

[0017] Figure 3 - (a) and (b) illustrate the changes in oxygen concentration and oxygen content in an 11 ml gas-sealed bottle with respect to the removal time of oxygen scavenging membranes containing different amounts of β-carotene.

[0018] Figure 4 This study describes the variation in oxygen concentration in an 11 ml gas-sealed vial with respect to the clearance time of membranes containing 1 wt% β-carotene, lycopene, retinol, or astaxanthin. Detailed Implementation

[0019] The invention can be more readily understood by referring to the following detailed description of various embodiments, examples, and tables with their related descriptions. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms such as those defined in common dictionaries should be interpreted as having the same meaning as in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless so explicitly defined herein. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0020] It must be noted that, unless the context explicitly requires otherwise, the singular forms “a / an” and “the” as used herein include multiple indicators. Therefore, unless the context requires otherwise, singular terms should include plural terms, and plural terms should include singular terms.

[0021] The word "or" when referring to a list of two or more items covers the interpretation of all the following terms: any one of the items in the list, all the items in the list, and any combination of the items in the list.

[0022] Typically, ranges herein are expressed as “about” a particular value and / or “about” another particular value. When such ranges are expressed, one embodiment includes a range from one particular value and / or to another particular value. Similarly, when values ​​are expressed as approximate values ​​using the term “about,” it should be understood that the particular values ​​form another embodiment. It will be further understood that the endpoints of each of the ranges are meaningful relative to and independent of the other endpoint. As used herein, the term “about” means ±20%, preferably ±10%, and even more preferably ±5%.

[0023] Unless the context explicitly requires otherwise, throughout the specification and claims, the terms "comprise" and similar terms should be interpreted in an inclusive sense, rather than an exclusive or exhaustive sense; in other words, they should be interpreted as "including (but not limited to)". Furthermore, when used in this application, the terms "in this document," "above," "below," and similar terms should refer to the entire application and not any specific part of it.

[0024] "Reduced oxygen atmosphere" or "reduced oxygen atmosphere" refers to a packaging material with a reduced oxygen partial pressure compared to the oxygen partial pressure in the Earth's atmosphere at standard temperature and pressure at sea level. Reduced oxygen atmosphere packaging may include modified atmosphere packaging in which the oxygen partial pressure is lower than the oxygen partial pressure in the Earth's atmosphere at standard temperature and pressure at sea level.

[0025] According to the present invention, "encapsulated article" refers to a manufactured article, which may be in the form of a mesh, such as a single or multiple layer film, a single or multiple layer sheet; a container, such as a bag, shrink bag, pouch; a shell, tray, covered tray, outer tray, shape shrink package, vacuum surface package, flow cladding package, thermoforming package, encapsulation plug, or a combination thereof. Those skilled in the art will understand that, according to the present invention, the encapsulated article may comprise flexible, rigid, or semi-rigid materials and may be thermally shrinkable or thermally non-shrinkable, or oriented or non-oriented.

[0026] As used in this article, "intermediate layer" means a layer that is situated between and in contact with at least two other layers.

[0027] As used in this article, “outer layer” is a relative term and does not necessarily refer to the surface layer.

[0028] The term "outer layer" refers to a layer that includes the outermost surface of a film or product. For example, an outer layer may form the outer surface of a package that overlaps with the outer layer of another package during the heat-sealing of two packages.

[0029] The term "inner layer" refers to the layer that includes the innermost surface of a film or product. For example, the inner layer forms the inner surface of a closed package. The inner layer can be a food contact layer and / or a sealant layer.

[0030] The term "adhesive layer" refers to a layer or material disposed on one or more layers to facilitate adhesion of one layer to another surface. Preferably, the adhesive layer is disposed between two layers of a multilayer film to hold the two layers in position relative to each other and prevent unwanted delamination. Unless otherwise specified, the adhesive layer may have any suitable composition that provides a desired degree of adhesion on one or more surfaces in contact with the adhesive layer material. Optionally, the adhesive layer disposed between a first and a second layer in a multilayer film may include components of both the first and second layers to facilitate simultaneous adhesion of the adhesive layer to both the first and second layers, to opposite sides of the adhesive layer.

[0031] As used herein, the terms "seal layer / sealing layer," "heat-sealing layer," and "sealant layer" refer to an outer film layer, or a layer relating to sealing the film to itself, to another film layer of the same film or another film, and / or to another article that is not a film (e.g., a tray). Generally, a sealant layer is an inner layer of any suitable thickness that provides sealing of the film to itself or another layer. Regarding packages with only fin seals, the term "sealant layer" typically refers to the inner surface film layer of the package, as opposed to a surround seal. Inner layers often also serve as food contact layers in food packaging.

[0032] "Food contact layer" refers to the part of the packaging material that comes into contact with the food product.

[0033] In one embodiment, the present invention provides an oxygen-removing formulation comprising an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids.

[0034] In a preferred embodiment of the invention, the oxidizable polymer resin may include an olefin compound containing a double bond, such as...

[0035] (i) Homopolymers and copolymers of olefin monomers, such as ethylene and propylene, and higher 1-olefins, such as 1-butene, 1-hexene, 1-hexene, or 1-octene. Preferred are polyethylene LDPE and LLDPE, HDPE, and polypropylene;

[0036] (ii) Homopolymers and copolymers of olefin monomers having diene monomers, such as butadiene, isoprene, and cyclic olefins such as norbornene; or

[0037] (iii) A copolymer of one or more 1-olefins and / or dienes having carbon monoxide and / or other vinyl monomers, including (but not limited to) acrylic acid and its corresponding acrylates, methacrylic acid and its corresponding esters, vinyl acetate, vinyl alcohol, vinyl ketone, styrene, maleic anhydride and vinyl chloride.

[0038] More preferably, the oxidizable polymer resin used in this invention may be polybutadiene or styrene-butadiene copolymer.

[0039] A transition metal catalyst is added to a deoxygenating formulation to facilitate the oxidation reaction of oxidizable polymer resins. The transition metal catalyst prepares the formulation as an "activated" deoxygenating formulation. The transition metal catalyst may be a salt containing a metal selected from the first, second, or third transition series of the periodic table. The metal is preferably one of the elements in the Rh, Ru, or Sc to Zn series (i.e., Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn), more preferably at least one of Mn, Fe, Co, Ni, and Cu, and most preferably Co. Suitable anions of such salts include (but are not limited to) chlorides, acetates, octanoates, oleates, stearates, palmitates, 2-ethylhexanoates, neocaprates, decanoates, neoodecanoates, and naphthenates. Examples of the use of these salts are given in US 3,840,512 and US 4,101,720, such as cobalt neocaprate.

[0040] In one embodiment of the present invention, carotenoids can be used as photosensitizers to trigger the oxygen removal function. The carotenoids are preferably selected from the group consisting of: lycopene, zeaxanthine, retinol, cantaxanthine, α-carotene, β-carotene, γ-carotene and δ-carotene, astacin, astaxanthin, chrysanthemaxanthin, torularhodin, violaxanthin, capsanthin, capsorubin, riboflavin, xanthophyll, lutein, and any combination thereof, and more preferably β-carotene.

[0041] According to the present invention, the amount of transition metal catalyst, based on the weight of the oxidizable polymer resin, may be from about 0.001 to about 5 wt%, preferably from about 0.01 to about 4 wt%, and more preferably from about 0.1 to about 2 wt%; and the amount of photosensitizer ranges from about 0.5 to about 5 wt%, preferably from about 0.75 to about 4 wt%, and more preferably from about 1 to about 3 wt%.

[0042] Although not required, additives may be used in deoxygenating formulations. Common additives include (but are not limited to) (i) fillers and reinforcing agents, such as calcium carbonate, silica, glass fiber, glass beads, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite, wood flour, other natural product powders, synthetic fibers; stearates (such as zinc stearate or calcium stearate) used as fillers; (ii) pigments, such as carbon black, titanium dioxide in its rutile or anatase form, and other colorants; (iii) light stabilizers and / or antioxidants; and (iv) processing additives, such as anti-slip / anti-caking additives, plasticizers, optical brighteners, antistatic agents, and foaming agents.

[0043] In the process of producing the deoxygenated formulation of the present invention, the transition metal catalyst, photosensitizer, and optional additives may be blended with the oxidizable polymer resin simultaneously or sequentially or immediately before the actual processing steps.

[0044] The deoxygenating formulation of the present invention can be in the form of a deoxygenating film, and can be applied to a substrate by drying or wetting spraying or dust removal, or by roller coating or coating using a Mayer bar or doctor blade, or by printing means (e.g., using gravure or flexographic printing) or by using electrostatic transfer.

[0045] The oxygen-removing formulation according to the present invention can be used to manufacture encapsulated articles, such as single or multilayer plastic films, sheets, laminates, bags, bottles, styrofoam cups, utensils, bubble wrap, boxes, and encapsulation layers. The encapsulated articles can be manufactured by any process available to those skilled in the art, including (but not limited to) extrusion, extrusion blow molding, film casting, film blow molding, calendering, injection molding, blow molding, compression molding, thermoforming, textiles, blow extrusion, and rotational casting.

[0046] The encapsulation article can be a multi-layer food encapsulation comprising an outer layer, a food contact layer, and an oxygen-absorbing film. The outer layer utilizes a polyolefin resin, preferably (i) EVA, (ii) EAO (such as VLDPE), and (iii) a blend of ethylene-hexene-1 copolymer with a melting point (mp) of 80 to 98°C. The food contact layer is an inner layer and may also function as a sealant layer. Suitable materials for the food contact layer should be thermally stable above 150°C and should comply with all FDA guidelines for contact with aqueous and fatty foods under all conditions experienced during encapsulation, storage, and cooking. Examples of food contact layers include polyesters, acrylic polymers, and silicones. A preferred food contact layer is a polypropylene (PP) layer.

[0047] Multilayer food packaging articles may further include an intermediate layer disposed between the oxygen-absorbing membrane and the outer layer and / or between the oxygen-absorbing membrane and the food contact layer. A common suitable intermediate layer is an adhesive layer on either side of the oxygen-absorbing membrane to which the outer layer or the food contact layer is attached. A preferred component of the adhesive layer is EMAC SP 1330 and polyurethane (PU).

[0048] In one embodiment of the invention, a multilayer encapsulation film for food packaging can be produced by coating an oxygen-scavenging compound onto a plastic substrate to create an oxygen-scavenging film. After drying, the oxygen-scavenging film can be attached to a food contact layer including an adhesive. Alternatively, a multilayer encapsulation film for food packaging can be produced by coating an oxygen-scavenging compound onto a food contact layer to create an oxygen-scavenging film. Subsequently, the oxygen-scavenging film, comprising an outer layer, a food contact layer, an oxygen-scavenging film, and optionally an adhesive layer as an intermediate layer, should be rolled to prevent the oxygen-scavenging film from contacting oxygen.

[0049] One advantage of the oxygen-scavenging formulation of the present invention is that it does not require activation of the oxidation reaction by water, high temperature, or light triggering. However, UV light or pulsed light triggering processes typically promote the oxidation reaction of the oxygen scavenger. Therefore, the oxygen-scavenging formulation of the present invention is also applicable to any conventional light-triggered process or system.

[0050] In view of the foregoing, the present invention also provides a method for reducing the oxygen atmosphere in a packaged article, comprising providing an oxygen-removing agent to the packaged article to allow the oxygen-removing agent to come into contact with oxygen, wherein the oxygen-removing agent comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids.

[0051] The present invention also provides a method for reducing the oxygen atmosphere in an encapsulated article, comprising a) exposing an oxygen-removing formulation to UV radiation to trigger oxygen removal, wherein the oxygen-removing formulation includes an oxidizable polymer resin and a transition metal catalyst; and b) providing the triggered oxygen-removing formulation to the inside of the encapsulated article to allow the oxygen-removing formulation to come into contact with oxygen and reduce the oxygen atmosphere in the encapsulated article.

[0052] The present invention further provides a method for reducing the oxygen atmosphere in a packaged article, comprising the following steps: a) exposing a multilayer packaging film including an oxygen-removing film to UV radiation to trigger oxygen removal; wherein the oxygen-removing film is composed of an oxygen-removing formulation comprising an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids; and b) sealing the multilayer packaging film to form a packaged article to allow the oxygen-removing formulation to come into contact with oxygen and reduce the oxygen atmosphere in the packaged article.

[0053] According to the present invention, the exposure step includes exposing the deoxygenating formulation to UV radiation having a concentration of approximately 250 mJ / cm². 2 Up to 600mJ / cm 2 The preferred value is approximately 350 mJ / cm³. 2 Up to 600mJ / cm 2 More preferably about 450 mJ / cm 2 Up to 600mJ / cm 2 Energy density in the ultraviolet C (UVC) band.

[0054] In embodiments of the present invention, the oxygen-removing agent is present on the inner layer of the packaged article.

[0055] The embodiments described above are not intended to be exhaustive or to limit the invention to the precise forms disclosed above. Those skilled in the art will recognize that, although the specific embodiments and examples of the invention described above are for illustrative purposes, various equivalent modifications can be made within the scope of the invention.

[0056] Example

[0057] Example 1: Fabrication of a multilayer structure including an oxygen removal membrane

[0058] To prepare an oxygen-scavenging formulation containing β-carotene, 0.03 g of β-carotene (1 wt%) was added to 9 g of butyl acetate solvent, and the resulting solution was heated to dissolve the β-carotene. Under continuous stirring and heating, 3 g of styrene-butadiene-styrene and 0.03 g of cobalt neodecanoate (1 wt%) were subsequently added to the solution to obtain an oxygen-scavenging formulation containing 1 wt% β-carotene. (The above weight percentages are based on the total weight of styrene-butadiene-styrene.) The formulation was coated onto a terephthalate (PET) substrate using a doctor blade. The coated PET substrate was dried at 80 °C, resulting in an oxygen-scavenging film with a thickness of 45 μm on the PET substrate.

[0059] The comparison membrane was prepared according to the process described above, wherein a blank membrane was obtained without the addition of β-carotene, and an oxygen-removing membrane containing benzophenone was obtained by replacing β-carotene with 0.03 g of benzophenone (1 wt% of the total weight of styrene-butadiene-styrene).

[0060] Example 2: Exposure to UV lamps

[0061] The membrane containing β-carotene, the blank membrane, and the membrane containing benzophenone prepared in Example 1 were cut into pieces with an area of ​​9 cm². 2 The film was then applied to the surface of each of the formulations, which was subsequently exposed to a 400W UV lamp at a distance of 7 cm, with the intensity distribution profiles listed in Table 1, for 10 seconds.

[0062] Table 1

[0063] Electromagnetic band (wavelength) <![CDATA[Power density (mW / cm 2 )]]> VIS band (400-800nm) 28 UVA band (320-400nm) 26 UVB band (275-320nm) 24 UVC band (200-275nm) 19 Total wavelength (200-800nm) 97

[0064] Following exposure, the membranes were individually placed in 11 ml airtight bottles. The oxygen concentration in each bottle was measured at intervals using gas chromatography (Trace 1310). Figure 1 As demonstrated, the oxygen removal effect of membranes containing 1 wt% β-carotene or 1 wt% benzophenone can be triggered by exposure to UV light for 30 seconds. Furthermore, over 500 hours, the oxygen removal effect achieved by the membrane containing 1 wt% β-carotene is similar to that achieved by the membrane containing 1 wt% benzophenone (a conventional trigger). These results demonstrate that conventionally used triggers (e.g., benzophenone) can be replaced by natural and water-insoluble β-carotene.

[0065] Example 3: The effect of energy density of ultraviolet C light

[0066] The oxygen-scavenging membrane containing 1 wt% β-carotene prepared in Example 1 was individually exposed to an atmosphere with a voltage of 19 mV / cm. 2A 400W UV lamp with UVC power density for 0, 15, 20, 25, or 30 seconds. UVC band energy density (mJ / cm²). 2 This can be achieved by increasing the power density (19mV / cm). 2 The oxygen concentration was calculated by multiplying the exposure time (0, 15, 20, 25, or 30 seconds). Similarly, the exposed membrane was individually placed in 11 ml airtight bottles. The oxygen concentration in each bottle was measured at intervals by gas chromatography (Trace 1310). Figure 2 As shown in (a) and 2(b), when a deoxygenating membrane containing 1 wt% β-carotene is exposed to an atmosphere with 285 mJ / cm², 2 When exposed to UVC light with higher energy density, the oxygen removal effect of an oxygen-removing membrane containing 1 wt% β-carotene can be triggered within 25 hours.

[0067] Example 4: The effect of the amount of β-carotene

[0068] 0.015 g, 0.03 g, and 0.09 g of β-carotene (0.5 wt%, 1 wt%, or 3 wt%) were added to 9 g of butyl acetate solvent, and the resulting solutions were heated to dissolve the β-carotene. Under continuous stirring and heating, 3 g of styrene-butadiene-styrene and 0.03 g of cobalt neodecanoate (1 wt%) were subsequently added to each of the solutions to obtain three oxygen-scavenging formulations containing 0.5 wt%, 1 wt%, and 3 wt% β-carotene, respectively. (The above weight percentages are calculated based on the total weight of styrene-butadiene-styrene.) The formulations were coated onto a terephthalate (PET) substrate using a doctor blade. The coated PET substrate was dried at 80 °C, resulting in an oxygen-scavenging film with a thickness of 45 μm on the PET substrate.

[0069] Oxygen-absorbing membranes containing 0.5 wt%, 1 wt%, and 3 wt% β-carotene were cut into pieces with an area of ​​9 cm². 2 The sheet, with the surface coated with the deoxygenating agent exposed at a distance of 7 cm, has a strength of 19 mW / cm². 2 The power density of a 400W UV lamp in the UVC band for 30 seconds is equal to 570mJ / cm². 2 (Energy density). After exposure, the membrane was individually placed in 11 ml airtight bottles. The oxygen concentration in each bottle was measured at intervals by gas chromatography (Trace 1310).

[0070] like Figure 3 As shown in (a) and 3(b), when passing through a medium with 570 mJ / cm 2 After being triggered by UVC light of high energy density, membranes containing 1 wt% or more of β-carotene can exhibit oxygen removal effects within fifty hours.

[0071] Example 5: Preparation of oxygen-free encapsulation

[0072] 0.009 g, 0.03 g, and 0.09 g of β-carotene (0.3 wt%, 1 wt%, or 3 wt%) were added to 9 g of butyl acetate solvent, and the resulting three solutions were heated to dissolve the β-carotene. Under continuous stirring and heating, 3 g of styrene-butadiene-styrene and 0.03 g of cobalt neodecanoate (1 wt%) were then added to the solution to obtain an oxygen-scavenging formulation containing β-carotene. (The above weight percentages are based on the total weight of styrene-butadiene-styrene). The formulation was then coated onto a polypropylene (PP) substrate using a doctor blade. The coated PP substrate was dried at 80°C, resulting in an oxygen-scavenging film with a thickness of 25 μm. A #6 coating rod was used to coat a polyurethane (PU) adhesive onto a polyethylene terephthalate (PET) substrate. After the PET substrate is coated and dried, the PU adhesive side of the PET substrate is attached to the deoxygenation film of each of the PP substrates to form a thin layer. The formed thin layer is then placed independently in an aluminum foil bag.

[0073] The resulting thin layer was cut into 3×3cm pieces. 2 Two thin-layer sheets from the same thin layer were arranged with their PP substrates facing each other, and the two sheets were sealed to form a package. 11 ml of air was then injected into each of the packages. The oxygen concentration in the packages was measured at intervals using gas chromatography (trace 1310). The results are shown in Table 2:

[0074] Table 2

[0075]

[0076] The results above demonstrate that when the amount of β-carotene is 3 wt% or more based on the weight of styrene-butadiene-styrene, the oxygen-removing formulation can significantly reduce the oxygen concentration in the encapsulation without the use of triggering agents or heating or light.

[0077] Example 6: Other carotenoids

[0078] Membranes, each containing 1 wt% β-carotene, lycopene, retinol, or astaxanthin, were prepared according to the process described in Example 1 and then exposed to a 400W UV lamp as described in Example 2 at a distance of 7 cm for 30 seconds. Figure 4 As shown, the deoxygenation effect can be triggered by all membranes containing 1 wt% of different carotenoids.

Claims

1. An oxygen-scavenging formulation comprising an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids, wherein the oxygen-scavenging formulation is in the form of an oxygen-scavenging film coated on a substrate, the substrate being an outer layer and / or an inner layer of an encapsulated article, wherein the encapsulated article contains oxygen-containing air, and the oxygen-scavenging film is configured with the outer layer and / or the inner layer such that the oxygen-scavenging film can reduce the oxygen concentration in the air within the encapsulated article, wherein the amount of the transition metal catalyst is 0.1 to 5 wt% by weight of the oxidizable polymer resin, and wherein the carotenoid is zeaxanthin, retinol, canthaxanthin, β-carotene, astaxanthin, astaxanthin, chrysanthemin, erythropoietin, zeaxanthin, capsanthin, riboflavin, lutein, or progesterone.

2. The deoxygenating formulation according to claim 1, wherein the amount of the photosensitizer is between 0.5 and 5 wt% based on the weight of the oxidizable polymer resin.

3. The deoxygenating formulation according to claim 1, wherein the deoxygenating film is coated on the outer layer of the packaged article and not coated on the inner layer of the packaged article.

4. The deoxygenating formulation according to claim 1, wherein the deoxygenating film is coated on the inner layer of the packaged article and not coated on the outer layer of the packaged article.

5. The deoxygenating formulation according to claim 1, wherein the encapsulation article further comprises an intermediate layer and / or an adhesive layer.

6. A method for reducing the oxygen atmosphere in an encapsulated article, comprising coating an oxygen-removing agent onto an outer layer and / or an inner layer of the encapsulated article in the form of an oxygen-removing film, wherein the encapsulated article contains oxygen-containing air, and the oxygen-removing film is configured with the outer layer and / or the inner layer such that the oxygen-removing film can reduce the oxygen concentration in the air within the encapsulated article, wherein the oxygen-removing agent comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids, wherein the amount of the transition metal catalyst is 0.1 to 5 wt% by weight of the oxidizable polymer resin, and wherein the carotenoid is zeaxanthin, retinol, canthaxanthin, β-carotene, astaxanthin, astaxanthin, chrysanthemin, erythropoietin, zeaxanthin, capsanthin, riboflavin, lutein, or progesterone.

7. The method of claim 6, wherein the amount of the photosensitizer ranges from 0.5 to 5 wt% based on the weight of the oxidizable polymer resin.

8. A method for reducing the oxygen atmosphere in a packaged article, comprising: a) Exposing the deoxygenating formulation to UV radiation to trigger deoxygenation, wherein the deoxygenating formulation comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids, wherein the amount of the transition metal catalyst is 0.1 to 5 wt% by weight of the oxidizable polymer resin, and wherein the carotenoid is zeaxanthin, retinol, canthaxanthin, β-carotene, astaxanthin, astaxanthin, chrysanthemin, erythropoietin, zeaxanthin, capsanthin, riboflavin, lutein, or progesterone; and b) Applying the triggered deoxygenating formulation to the packaged article in the form of a deoxygenating film, wherein the packaged article contains oxygen-containing air, and the deoxygenating film is configured such that it can reduce the concentration of oxygen in the air within the packaged article.

9. The method of claim 8, wherein the exposure step comprises exposing the deoxygenating formulation to an environment having approximately 250 mJ / cm². 2 Up to 600 mJ / cm 2 The energy density of UV radiation in the UVC band.

10. The method according to claim 8 or 9, wherein the amount of the photosensitizer ranges from 0.5 to 5 wt% based on the weight of the oxidizable polymer resin.

11. A method for reducing the oxygen atmosphere in an encapsulated article, comprising: a) Coating an oxygen-removing formulation onto a substrate to form an oxygen-removing film, wherein the substrate is an outer layer and / or an inner layer of an encapsulated article, and the oxygen-removing formulation comprises an oxidizable polymer resin, a transition metal catalyst, and a photosensitizer selected from one or more carotenoids, wherein the amount of the transition metal catalyst is 0.1 to 5 wt% based on the weight of the oxidizable polymer resin, and wherein the carotenoid is zeaxanthin, retinol, canthaxanthin, β-carotene, astaxanthin, astaxanthin, chrysanthemin, erythropoietin, zeaxanthin, capsanthin, riboflavin, lutein, or progesterone; b) Expose the substrate, including the deoxygenation membrane, to UV radiation to trigger deoxygenation; and c) The substrate is sealed to form the packaged article, wherein the packaged article contains air containing oxygen, and the oxygen removal membrane is configured with the outer layer and / or the inner layer such that the oxygen removal membrane can reduce the concentration of oxygen in the air within the packaged article.

12. The method of claim 11, wherein the exposure step comprises exposing the deoxygenation membrane to an environment with approximately 250 mJ / cm². 2 Up to 600 mJ / cm 2 The energy density of UV radiation in the UVC band.

13. The method according to claim 11 or 12, wherein the amount of the photosensitizer ranges from 0.5 to 5 wt% based on the weight of the oxidizable polymer resin.

14. The method according to claim 11 or 12, wherein the encapsulated article further comprises an intermediate layer and / or an adhesive layer.

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