Deoxidizer composition, method for producing same, and deoxidizer package

Abstract

A deoxidizer composition containing iron powder, activated carbon, water, a halide of an alkaline earth metal, and an alkaline substance, the content of the activated carbon being from 20 parts by mass to 40 parts by mass (inclusive) per 100 parts by mass of the content of the iron powder, the content of the water being from 230 parts by mass to 370 parts by mass (inclusive) per 100 parts by mass of the content of the activated carbon, the content of the halide of the alkaline earth metal is from 50 parts by mass to 65 parts by mass (inclusive) with respect to 100 parts by mass of the water content.

Description

Technical Field

[0001] The present invention relates to a deoxidizer composition and a method for producing the same, and a deoxidizer package. Background Art

[0002] In the past, deoxidizers using the oxidation reaction of iron powder (hereinafter referred to as iron-based deoxidizers) have been proposed. Commercially available deoxidizers (e.g., trade name "ageless", manufactured by Mitsubishi Gas Chemical Co., Ltd.) have been widely used to maintain the quality and freshness of food, medicine, etc. by sealing them together with items such as food and medicine in a gas-tight container and removing oxygen from the container.

[0003] Iron-based deoxidizers include "moisture-dependent" deoxidizers that start absorbing oxygen by utilizing moisture evaporated from stored objects, and "self-reactive" deoxidizers in which moisture required for the oxygen absorption reaction of iron is preliminarily contained in the deoxidizer composition.

[0004] In the “self-reactive” deoxidizer, by allowing a moisture supply agent such as an inorganic filler impregnated with water to exist in the deoxidizer composition, water required for the oxygen absorption reaction of iron can be supplied from the moisture supply agent to iron.

[0005] However, since the self-reactive deoxidizer contains water in advance, when a stored object such as dry food or medicine containing less water than the self-reactive deoxidizer (in other words, having a lower water activity) is stored, there is a problem that water is transferred from the deoxidizer composition to the stored object, and the water content of the stored object changes. In addition, when water is transferred to the stored object, water required for the oxygen absorption reaction of iron is lost from the deoxidizer composition, and there is also a problem that the oxygen absorption performance is reduced.

[0006] The transfer of water from the deoxidizer composition to the stored object tends to occur more easily as the difference in water activity between the stored object and the deoxidizer composition increases. Therefore, studies have been conducted to obtain a deoxidizer composition having a water activity close to that of the stored object.

[0007] For example, Patent Document 1 proposes a deoxidizer composition comprising iron powder, calcium chloride, water, and a water-retaining carrier, wherein the contents of water and calcium chloride are controlled within a prescribed range.

[0008] The deoxidizer composition proposed in Patent Document 1 solves the problem of water transfer to stored objects having a low water activity, and exhibits excellent oxygen absorption performance even in a low-humidity atmosphere.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent No. 6690201 Summary of the invention

[0012] Problem that the invention aims to solve

[0013] On the other hand, the deoxidizer composition showing a relatively low water activity (so-called medium water activity) tends to have poor oxygen absorption performance compared to the deoxidizer composition with a high water activity. In order to increase the oxygen absorption, it is necessary to use a large amount of iron powder and water. However, if iron powder and water are used in large quantities, the amount of hydrogen generated by these reactions will increase during oxygen absorption, which becomes the cause of container deformation and rupture. Therefore, as a deoxidizer composition with a medium water activity, it is required to absorb a large amount of oxygen while suppressing the amount of hydrogen generated.

[0014] Therefore, an object of the present invention is to provide a deoxidizer composition having a moderate water activity, excellent oxygen absorption performance, and a small amount of hydrogen generation, a method for producing the same, and a deoxidizer package.

[0015] Solutions for solving problems

[0016] That is, the main configuration of the present invention is as follows.

[0017] [1] A deoxidizer composition comprising: iron powder, activated carbon, water, an alkaline earth metal halide, and an alkaline substance,

[0018] The content of the activated carbon is 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the iron powder.

[0019] The content of the water is 230 parts by mass or more and 370 parts by mass or less relative to 100 parts by mass of the activated carbon,

[0020] The content of the alkaline earth metal halide is 50 parts by mass or more and 65 parts by mass or less relative to 100 parts by mass of the water content.

[0021] [2] The deoxidizer composition according to [1] above, wherein the alkaline earth metal halide is one or more selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide and calcium bromide.

[0022] [3] The deoxidizer composition according to [1] or [2], wherein the alkaline substance is one or more selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, and salts of weak acids and strong bases.

[0023] [4] The deoxidizer composition according to any one of [1] to [3] above, wherein the alkaline substance is calcium hydroxide.

[0024] [5] The deoxidizer composition according to any one of [1] to [4] above, further comprising a swelling agent.

[0025] [6] The deoxidizer composition according to [5] above, wherein the swelling agent is one or more selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite, and sodium bentonite.

[0026] [7] The deoxidizer composition according to [5] or [6], wherein the content of the swelling agent is 3 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the water.

[0027] [8] The deoxidizer composition according to any one of [1] to [7] above, wherein the deoxidizer composition is in the form of granules.

[0028] [9] The deoxidizer composition according to any one of [1] to [8] above, wherein the water activity of the deoxidizer composition is 0.40 or more and 0.60 or less.

[0029]

[10] A method for producing a deoxidizer composition, which is a method for producing the deoxidizer composition described in any one of [1] to [9] above, comprising the step of mixing iron powder, activated carbon, water, an alkaline earth metal halide and an alkaline substance.

[0030]

[11] An oxygen scavenger package comprising: the oxygen scavenger composition according to any one of [1] to [9] above, and an air-permeable packaging material containing the oxygen scavenger composition.

[0031] Effects of the Invention

[0032] According to the present invention, there can be provided a deoxidizer composition having a moderate water activity, excellent oxygen absorption performance, and a small amount of hydrogen generation, a method for producing the same, and a deoxidizer package. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the deoxidizer composition and the method for producing the deoxidizer composition, and the deoxidizer package of the present invention will be described in detail.

[0034] It should be noted that in this specification, the term "A to B" for numerical values ​​means "A or more and B or less" (when A < B) or "A or less and B or more" (when A > B). In addition, in the present invention, a combination of preferred embodiments is a more preferred embodiment.

[0035] [Deoxidizer composition]

[0036] The deoxidizer composition of the present invention comprises: iron powder, activated carbon, water, alkaline earth metal halide, and alkaline substance, wherein the content of the activated carbon is 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the iron powder, the content of the water is 230 parts by mass or more and 370 parts by mass or less relative to 100 parts by mass of the activated carbon, and the content of the alkaline earth metal halide is 50 parts by mass or more and 65 parts by mass or less relative to 100 parts by mass of the water.

[0037] The deoxidizer composition of the present invention has the above-mentioned structure and shows a moderate water activity, can exhibit excellent oxygen absorption performance, and can also suppress the generation of hydrogen.

[0038] It should be noted that, in the present specification, “medium water activity” means that the water activity is within the range of “0.4 or more and 0.6 or less”.

[0039] The reason why the deoxidizer composition of the present invention exhibits the above-mentioned effect is not yet clear, but one of the reasons is considered to be the following.

[0040] Conventionally, the moisture supplying agent contained in the self-reactive deoxidizer composition is a material obtained by using an inorganic filler such as silica or diatomaceous earth as a water-retaining carrier and loading water on the water-retaining carrier.

[0041] In contrast, the present invention is characterized in that activated carbon is particularly selectively used as a water-retaining carrier. It is speculated that since activated carbon is also a component that acts as a reaction promoter for the oxygen absorption reaction of iron, the oxygen absorption performance of the obtained deoxidizer composition is improved compared with the water-retaining carriers such as silica used in the past. It is also speculated that activated carbon tends to absorb more water per unit mass (water retention) than silica, etc., and even if the moisture supply agent is reduced, sufficient water can be supplied to the iron, and the oxygen absorption performance is improved compared to the case of using silica, etc. For these reasons, it is believed that when using activated carbon as a water-retaining carrier, the oxygen absorption per unit mass of the deoxidizer composition (original powder) can be increased.

[0042] In addition, the deoxidizer composition of the present invention is characterized in that it contains an alkaline substance. By containing an alkaline substance, the surface of iron (especially the water present on the surface) can be kept alkaline. As a result, it is believed that the hydrogen ion concentration in the reaction water can be reduced on the surface of iron during the oxygen absorption reaction, and the situation that hydrogen ions are reduced by iron to produce hydrogen can be effectively suppressed.

[0043] It is also believed that the deoxidizer composition of the present invention can exhibit a moderate water activity and achieve both the effect of improving oxygen absorption performance and the effect of suppressing hydrogen generation by controlling the blending amounts of activated carbon, water and alkaline earth metal halide to a predetermined ratio.

[0044] Hereinafter, each component and the like will be described.

[0045] (Iron Fan)

[0046] The deoxidizer composition of the present invention contains iron powder.

[0047] The iron powder in the deoxidizer composition of the present invention is the main agent for the deoxidation reaction.

[0048] The iron powder is not particularly limited, and preferably has an exposed surface of iron (metallic iron of zero valence), and may have an extremely thin oxide film as on a common metal surface within the range that does not hinder the effect of the present invention. Specifically, reduced iron powder, electrolytic iron powder, sprayed iron powder (atomized iron powder), etc. may be suitably used. In addition, pulverized materials such as cast iron and cut products may also be used.

[0049] The iron powder may be used alone or in combination of two or more kinds as required. Commercial products of these iron powders are easily available and can be used.

[0050] From the viewpoint of good contact with oxygen, the average particle size (D50) of the iron powder is, for example, 3000 μm or less, preferably 1000 μm or less, more preferably 500 μm or less, and further preferably 300 μm or less, and from the viewpoint of suppressing dust generation, it is preferably 1 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. Specifically, the average particle size (D50) of the iron powder is preferably 1 to 1000 μm, more preferably 10 to 500 μm, and further preferably 20 to 300 μm.

[0051] It should be noted that the iron powder having an average particle size within the above range can be obtained by appropriately selecting commercially available iron powder or by classifying using a sieve that matches the desired average particle size.

[0052] The average particle size of the iron powder can be measured by the method described in Examples.

[0053] In addition, from the viewpoint of oxygen absorption performance, the specific surface area of ​​the iron powder is preferably 0.03 m 2 / g or more, more preferably 0.05m 2 / g or more, and preferably 0.50 m / g from the viewpoint of suppressing dust generation. 2 / g or less, more preferably 0.20m 2 Specifically, the specific surface area of ​​the iron powder is preferably 0.03 to 0.50 m 2 / g, more preferably 0.05 to 0.20 m 2 / g.

[0054] It should be noted that the specific surface area of ​​the iron powder can be measured by the method described in the Examples.

[0055] The content of the iron powder is not particularly limited, but is preferably 15 mass % to 75 mass %, more preferably 20 mass % to 60 mass %, and further preferably 25 mass % to 50 mass % in the deoxidizer composition.

[0056] (Activated carbon)

[0057] The deoxidizer composition of the present invention contains activated carbon.

[0058] The activated carbon in the deoxidizer composition of the present invention functions as a reaction accelerator and a water-retaining carrier.

[0059] The activated carbon is not particularly limited, and the raw material may be wood, coconut shell, coal, or the like. From the viewpoint of using the deoxidizer composition of the present invention for food, at least one selected from wood and coconut shell is preferred.

[0060] The properties of the activated carbon are not particularly limited, but from the viewpoint of workability when producing the deoxidizer composition, a granular or powdery activated carbon having high fluidity is preferably used, and a spherical activated carbon is more preferred.

[0061] The activated carbon may be used alone or in combination of two or more kinds as required. Commercial products of these activated carbons are easily available and can be used.

[0062] In addition, for the average particle size of activated carbon, from the perspective of operability when manufacturing the deoxidizer composition, the powder is preferably 0.1 μm or more and 1000 μm or less, more preferably 1 μm or more and 100 μm or less, and further preferably 1 μm or more and 50 μm or less. As long as the activated carbon particles have a particle size within the above range, primary particles, aggregated particles, and granules can all be used. Activated carbon having a particle size within the above range can be used alone, or multiple activated carbons with different particle sizes can be mixed in any proportion and used. Commercial products of such activated carbon can be easily obtained and can also be used.

[0063] It should be noted that the average particle size of activated carbon can be measured by the method described in Examples.

[0064] The content of activated carbon is 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the content of iron powder, preferably 20 parts by mass or more and 30 parts by mass or less, more preferably 20 parts by mass or more and 25 parts by mass or less, and further preferably 20 parts by mass or more and 23 parts by mass or less. By setting the above range, a deoxidizer composition showing a moderate water activity, excellent oxygen absorption performance, and a small amount of hydrogen generated can be obtained. On the other hand, if the content of activated carbon is too little, there is a tendency that the moisture cannot be fully retained, the deoxidizer composition forms a slurry, or cannot fully exert its function as a reaction accelerator, and the oxygen absorption performance decreases.

[0065] (water)

[0066] The deoxidizer composition of the present invention contains water.

[0067] The water contained in the deoxidizer composition of the present invention is an essential component for the deoxidation reaction to proceed.

[0068] For the content of water, relative to 100 parts by mass of the content of activated carbon, it is 230 parts by mass or more and 370 parts by mass or less, preferably 250 parts by mass or more and 370 parts by mass or less, more preferably 270 parts by mass or more and 370 parts by mass or less, further preferably 300 parts by mass or more and 370 parts by mass or less, and further preferably 300 parts by mass or more and 350 parts by mass or less. By setting it to the above range, a deoxidizer composition showing a moderate water activity, excellent oxygen absorption performance, and a small amount of hydrogen generated can be obtained. On the other hand, if the content of water is too much, there is a tendency that the oxygen absorption performance is significantly reduced, and the amount of hydrogen generated also tends to increase.

[0069] (Alkaline earth metal halides)

[0070] The deoxidizer composition of the present invention contains a halide of an alkaline earth metal.

[0071] The alkaline earth metal halide in the deoxidizer composition of the present invention is a substance that catalyzes the oxidation reaction of iron powder and increases the activity of iron powder. In addition, the alkaline earth metal halide prevents the water contained in the deoxidizer composition from evaporating from the deoxidizer composition and exerts an effect of inhibiting the transfer of water to the stored object.

[0072] In order for iron to absorb oxygen, it is necessary to introduce moisture onto the surface of the iron, which utilizes the deliquescent phenomenon of metal salts.

[0073] Alkaline earth metal halides are metal salts that exhibit deliquescent properties and have greater solubility in water than alkali metal halides and the like, and are more likely to reduce water activity. Therefore, they are effective in preparing a deoxidizer composition (raw powder) having a medium water activity.

[0074] It should be noted that the alkaline earth metal halide is preferably contained in the deoxidizer composition in the form of an aqueous solution dissolved in water.

[0075] The alkaline earth metal halide is not particularly limited, and examples thereof include chlorides, bromides, and iodides of alkaline earth metals. Preferably, it is at least one selected from the group consisting of chlorides and bromides of alkaline earth metals.

[0076] Among them, from the perspectives of operability, safety, etc., the alkaline earth metal halide is preferably one or more selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide and calcium bromide; more preferably one or more selected from the group consisting of calcium chloride and magnesium chloride; further preferably calcium chloride.

[0077] The alkaline earth metal halide may be used alone or in combination of two or more as necessary. Commercially available products of the alkaline earth metal halide described above are easily available and can also be used.

[0078] The content of the alkaline earth metal halide is 50 parts by mass or more and 65 parts by mass or less, preferably 52 parts by mass or more and 62 parts by mass or less, and more preferably 52 parts by mass or more and 56 parts by mass or less, relative to 100 parts by mass of water. By setting the above range, a deoxidizer composition showing a moderate water activity, excellent oxygen absorption performance, and a small amount of hydrogen generation can be obtained. On the other hand, if the content of the alkaline earth metal halide is too much, there is a tendency for the oxygen absorption performance to decrease.

[0079] (Alkaline substances)

[0080] The deoxidizer composition of the present invention contains an alkaline substance.

[0081] The alkaline substance in the deoxidizer composition of the present invention plays a role in keeping the surface of the iron (especially the water present on the surface) alkaline. Therefore, it is believed that the hydrogen ion concentration in the reaction water can be reduced on the surface of the iron during the oxygen absorption reaction, and the situation that the hydrogen ions are reduced by the iron to generate hydrogen can be effectively suppressed.

[0082] The alkaline substance is not particularly limited, but is preferably one or more selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, and salts formed from weak acids and strong bases; more preferably one or more selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides; and further preferably alkaline earth metal hydroxides.

[0083] Examples of the alkali metal hydroxide include potassium hydroxide and sodium hydroxide, and among them, sodium hydroxide is preferred.

[0084] Examples of the hydroxide of the alkaline earth metal include calcium hydroxide and magnesium hydroxide, and among them, calcium hydroxide is preferred.

[0085] Examples of salts formed by weak acids and strong bases include phosphates, citrates, carbonates, and bicarbonates, among which phosphates and citrates are preferred. Specific examples of salts formed by weak acids and strong bases include trisodium phosphate, trisodium citrate, sodium bicarbonate, and sodium carbonate, among which trisodium phosphate and trisodium citrate are preferred.

[0086] The alkaline substance may be used alone or in combination of two or more as required. Commercial products of these alkaline substances are easily available and can also be used.

[0087] It should be noted that the oxidation rate of iron is known to be usually affected by pH, and the oxidation rate of iron tends to decrease in a high pH range. Therefore, from the viewpoint of maintaining high oxygen absorption performance, as an alkaline substance, calcium hydroxide (slaked lime) having a moderate solubility and also functioning as a pH adjusting agent is more preferably used.

[0088] The content of the alkaline substance is not particularly limited, but is preferably 0.2 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and further preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the content of the iron powder. By setting the above range, a deoxidizer composition showing a moderate water activity, excellent oxygen absorption performance, and a small amount of hydrogen generation can be obtained.

[0089] (Swelling Agent)

[0090] The deoxidizer composition of the present invention preferably further contains a swelling agent.

[0091] The swelling agent in the deoxidizer composition of the present invention is a substance having a binding function that swells with water and is used to keep the deoxidizer composition in a granular form. The swelling agent is preferably used in a substantially dry state, or in a semi-swollen or swollen state having absorbed a small amount or a required amount of water.

[0092] The swelling agent is not particularly limited as long as it is a generally known swelling agent, and known swelling agents, adhesives, tackifiers, and binders used in foods and the like can be used.

[0093] Examples of inorganic swelling agents include bentonites such as calcium bentonite and sodium bentonite, and clay minerals such as sodium montmorillonite. Examples of organic swelling agents include organic bentonite, natural products such as defatted frozen tofu, agar, starch, dextrin, gum arabic, gelatin, and casein, semi-synthetic products of cellulose such as crystalline cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, and hydroxyethyl cellulose, and semi-synthetic products such as lignin sulfonic acid and hydroxyethylated starch, and synthetic products such as water-insoluble polyvinyl alcohol and polyvinyl methyl ether.

[0094] Among them, the swelling agent is preferably one or more selected from the group consisting of clay minerals and cellulose-based semi-synthetic products.

[0095] Clay minerals are cheap and excellent in performance, so they are preferred. Clay minerals are also known as inorganic soaps and have the function of being a lubricant. In addition, clay minerals that are known to swell with water show high thixotropy and also show adhesion, so they are preferred.

[0096] In addition, cellulose-based semi-synthetic products are preferred because they exhibit excellent swelling properties.

[0097] In particular, from the viewpoint of low cost, strong bonding strength and excellent workability, the swelling agent is more preferably at least one selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite and sodium bentonite; and further preferably at least one selected from the group consisting of calcium bentonite and sodium bentonite.

[0098] The above-mentioned swelling agents may be used alone or in combination of two or more kinds as required. In addition, these swelling agents may be commercially available products.

[0099] From the viewpoint of suppressing dust generation and the viewpoint of the binding function, the average particle size of the swelling agent is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[0100] It should be noted that the average particle size of the swelling agent can be measured by the method described in the Examples.

[0101] The content of the swelling agent is preferably 3 parts by mass or more and 20 parts by mass or less, more preferably 5 parts by mass or more and 15 parts by mass or less, further preferably 5 parts by mass or more and 12 parts by mass or less, and still further preferably 5 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the water content. By setting the above range, a deoxidizer composition showing a moderate water activity, excellent oxygen absorption performance, and a small amount of hydrogen generation can be obtained.

[0102] (Other ingredients)

[0103] The deoxidizer composition of the present invention may contain other components as required in addition to the above components. Examples of other components include water-retaining carriers other than activated carbon, fluidity improvers, catalysts, odor adsorbents, heat dispersants, and the like.

[0104] The water-retaining carrier other than activated carbon is not particularly limited as long as it can retain water, and commonly available porous substances and highly water-absorbent resins can be used.

[0105] Examples of the porous substance include diatomaceous earth, zeolite, sepiolite, cristobalite, porous glass, silica, activated clay, acid clay, vermiculite, and wood flour.

[0106] Examples of the highly water-absorbent resin include polyacrylic acid salt-based resins, polysulfonic acid salt-based resins, polyacrylamide-based resins, polyvinyl alcohol-based resins, starch-based resins, cellulose-based resins, and polyalginic acid-based resins.

[0107] However, in the present invention, since activated carbon functions as a water-retaining carrier, it is not necessary to intentionally use a water-retaining carrier other than activated carbon, but it may be used within a range that does not hinder the effect of the present invention. From the viewpoint of increasing the ratio of activated carbon in the water-retaining carrier, the content of the water-retaining carrier other than activated carbon is preferably 5 parts by mass or less, more preferably 1 part by mass or less, and further preferably substantially no water-retaining carrier other than activated carbon is contained, that is, 0 parts by mass.

[0108] <Shape of deoxidizer composition>

[0109] The shape of the deoxidizer composition of the present invention is not particularly limited, but is preferably in the form of granules.

[0110] Here, the granular material may be aggregated particles or granulated materials.

[0111] Examples of the particle shape include spherical, substantially spherical, elliptical, and cylindrical. Since packing properties are better and the bulk density tends to be higher, spherical and substantially spherical shapes are preferred, and spherical shapes are more preferred.

[0112] The average particle size of the deoxidizer composition of the present invention is not particularly limited, and is preferably 0.3 mm or more and 5.0 mm or less, and more preferably 0.5 mm or more and 2.0 mm or less. By making the above average particle size 0.3 mm or more, it is possible to suppress the powder and granule contact portion of the packaging machine from being attached to the powder and granule due to static electricity during filling and packaging. In addition, by making the above average particle size 5.0 mm or less, the gap between the particles becomes too large, and the oxygen absorption per unit volume can be suppressed from decreasing. In order to obtain a deoxidizer composition having an average particle size within the above range, for example, a sieve with a mesh size of 0.3 mm and 5.0 mm can be used for screening.

[0113] In addition, the average particle size of the deoxidizer composition can be measured by the method described in the Examples.

[0114] <Characteristics of deoxidizer composition>

[0115] The deoxidizer composition of the present invention preferably shows a medium water activity.

[0116] The water activity indicates that the closer the value is to 1, the closer the water vapor pressure of water evaporated from the deoxidizer composition is to the water vapor pressure of pure water.

[0117] The water activity of the deoxidizer composition of the present invention is a so-called medium water activity, that is, preferably 0.40 to 0.60, more preferably 0.42 to 0.55, and even more preferably 0.42 to 0.53.

[0118] It should be noted that the method for measuring the water activity is not particularly limited, and the water activity can be measured using a known device such as a dew point water activity measuring device. Specifically, the water activity can be measured by the method described in the Examples.

[0119] Generally, when an article is stored in a sealed state, the greater the difference in water activity between the article to be stored and the deoxidizer composition, the easier it is for moisture transfer to occur. Therefore, from the viewpoint of inhibiting moisture transfer, the water activity of the deoxidizer composition is preferably the same as that of the article to be stored.

[0120] The oxygen scavenger composition of the present invention exhibits a medium water activity and is therefore suitable for preserving objects exhibiting a medium water activity.

[0121] Examples of the objects suitable for storage in the deoxidizer composition of the present invention include: foods such as rice / cereals, spices, dried bonito flakes / dried fish, and nori; industrial products such as electronic components with solder joints, metal threads, and metal knives such as razors; pharmaceuticals such as tablets, herbal medicines, and original drugs with a risk of hydrolysis; and various articles. Among them, it is suitable for the storage of pharmaceuticals.

[0122] [Method for producing deoxidizer composition]

[0123] The method for producing the deoxidizer composition of the present invention is not particularly limited, but preferably includes a step of mixing iron powder, activated carbon, water, an alkaline earth metal halide, and an alkaline substance.

[0124] According to this production method, iron powder, activated carbon, water, alkaline earth metal halide and alkaline substance are mixed until they are uniformly dispersed, thereby preparing a granular material and efficiently preparing a deoxidizer composition.

[0125] In addition, the mixing step may be (1) a step of mixing all the components at once, (2) a step of preparing an aqueous solution prepared by dissolving an alkaline earth metal halide in water, adding the aqueous solution to a mixture of iron powder, activated carbon, an alkaline substance, and, if necessary, a swelling agent and other components, and mixing the solution, or (3) a step of preparing an aqueous solution prepared by dissolving an alkaline earth metal halide and an alkaline substance in water, adding the aqueous solution to a mixture of iron powder, activated carbon, and, if necessary, a swelling agent and other components, and mixing the solution. From the viewpoint of obtaining a more homogeneous deoxidizer composition, the step (2) or (3) is preferred. In addition, in the case of (3), the alkaline earth metal halide reacts with the alkaline substance in the aqueous solution, and the concentration of the alkaline earth metal halide may change. Therefore, from the viewpoint of adding the alkaline earth metal halide to the iron powder and the like in an aqueous solution prepared to a desired concentration and mixing the solution, the step (2) is more preferred.

[0126] The mixing method is not particularly limited, and the mixing can be carried out by vibration mixing, mixing using a mixing device, etc. Specific examples of the mixing device include: Nauta mixer (manufactured by Hosokawa Micron Corporation), cone mixer (manufactured by Ohno Chemical Machinery Co., Ltd.), vertical granulator (manufactured by POWREX CORP.), high-speed mixer (manufactured by EARTHTECHNICA Co., Ltd.), and granulator (manufactured by AKIRAKIKO Co., Ltd.).

[0127] Since the main component of the deoxidizer, i.e., iron, can react with oxygen, it will slowly react with oxygen even in the absence of water, alkaline earth metal halides, etc. Therefore, it is preferred to mix in an inert atmosphere (in the case of a substantially closed system, the system is usually made to be an oxygen-free inert gas (e.g., N2) atmosphere) and to take appropriate heat removal measures.

[0128] [Deoxidizer packaging]

[0129] The deoxidizer package of the present invention comprises: the deoxidizer composition described above; and a gas-permeable packaging material containing the deoxidizer composition.

[0130] (Packaging Materials)

[0131] Examples of the packaging material include: a bag formed by laminating two sheets of air-permeable packaging material; a bag formed by laminating one sheet of air-permeable packaging material and one sheet of non-air-permeable packaging material; and a bag formed by folding one sheet of air-permeable packaging material and sealing the edges except the folded portion.

[0132] Here, when the air-permeable packaging material and the non-air-permeable packaging material are quadrilateral, the packaging material may be: a bag-shaped bag formed by overlapping two air-permeable packaging materials and heat-sealing four sides; a bag-shaped bag formed by overlapping one air-permeable packaging material and one non-air-permeable packaging material and heat-sealing four sides; a bag-shaped bag formed by folding one air-permeable packaging material and heat-sealing three sides excluding the folded portion. In addition, the packaging material may be a bag-shaped bag formed by forming the air-permeable packaging material into a tube and heat-sealing both ends and the main body of the tube.

[0133] (Breathable packaging material)

[0134] As the air permeable packaging material, a packaging material that is permeable to oxygen and carbon dioxide is selected. Among them, the air permeability resistance based on the Wang Yan tester method is preferably 40,000 seconds or less, more preferably 30,000 seconds or less, further preferably 20,000 seconds or less, and further preferably 10,000 seconds or less, and preferably 500 seconds or more, and more preferably 1000 seconds or more. Here, the air permeability resistance refers to the value measured by the method of JIS P8117 (1998). More specifically, it can be measured by the method described in the examples.

[0135] As the above-mentioned breathable packaging material, in addition to paper and nonwoven fabrics, a packaging material obtained by imparting breathability to a plastic film can also be used. As the plastic film, for example, a laminated film obtained by laminating and bonding a film of polyethylene terephthalate, polyamide, polypropylene, polycarbonate, etc., with a film of polyethylene, ionomer, polybutadiene, ethylene acrylic acid copolymer, ethylene methacrylic acid copolymer, or ethylene vinyl acetate copolymer as a sealant can be used. In addition, these laminates can also be used as breathable packaging materials.

[0136] As a method of imparting air permeability, various methods can be adopted in addition to perforation processing using a cold needle or a hot needle. When perforation processing is used to impart air permeability, the air permeability can be freely adjusted by the diameter, number, material, etc. of the perforated holes.

[0137] The thickness of the laminated film is preferably 30 μm to 300 μm, more preferably 40 μm to 250 μm. In this case, compared with a case where the thickness is not within the above range, a packaging material having excellent heat-sealing properties and packaging suitability while maintaining strength can be obtained.

[0138] (Application of deoxidizer package)

[0139] Since the deoxidizer package of the present invention contains the deoxidizer composition of the present invention, it has a medium water activity, excellent oxygen absorption performance, and a small amount of hydrogen generation. Therefore, it is suitable for storing objects having a medium water activity.

[0140] Specifically, the present invention is suitable for a method of deoxygenating the space inside a gas barrier container containing a stored object having a medium water activity by using the deoxidizer package of the present invention. According to this method, the transfer of water from the deoxidizer package to the stored object can be suppressed, and the space inside the gas barrier container can be deoxygenated efficiently, so that the quality of the stored object can be well maintained.

[0141] In addition, when the deoxidizer package of the present invention is used, it is preferred to prepare a package comprising the deoxidizer package, a stored object, and a gas barrier container for storing the deoxidizer package. In this case, from the viewpoint of maintaining the quality of the stored object, the humidity of the space in the gas barrier container is preferably 40%RH or more and 60%RH or less. In addition, the stored object is preferably one or more selected from food, industrial products, and medicines; more preferably, medicines.

[0142] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes all aspects covered by the concept of the present invention and the claims, and various modifications can be made within the scope of the present invention.

[0143] Example

[0144] Hereinafter, the present embodiment will be described in detail using Examples and Comparative Examples, but the present embodiment can be modified as appropriate as long as the effects of the present invention can be exhibited.

[0145] <Materials>

[0146] Materials and the like used in Examples and Comparative Examples are shown below.

[0147] Calcium chloride (CaCl2): Made by FUJIFILM Wako Pure Chemical Corporation, reagent premium grade

[0148] Iron powder: average particle size 100 μm, specific surface area 0.104 m 2 / g

[0149] [Measurement of average particle size of iron powder]

[0150] The average particle size of the iron powder is determined by measuring the average particle size (D50) at a cumulative frequency of 50% from the weight fraction based on the mesh size after vibration for 5 minutes using a standard sieve in accordance with ISO 3310-1:2000 (equivalent to JIS Z8801-1:2006).

[0151] [Specific surface area of ​​iron powder]

[0152] The specific surface area of ​​the iron powder (unit: m 2 / g) is measured based on the BET multipoint method in accordance with JIS Z8830:2013.

[0153] Activated carbon: Osaka Gas Chemicals Co., Ltd. "Shirayuki A", powder, average particle size 10 μm

[0154] [Average particle size of activated carbon]

[0155] The average particle size of the activated carbon is measured by using a laser diffraction / scattering particle size distribution measuring apparatus (“LA-960” manufactured by HORIBA, Ltd.) to obtain an average particle size (D50) at a cumulative frequency of 50% in a volume-based particle size distribution.

[0156] Calcium hydroxide (Ca(OH)2): Made by FUJIFILM Wako Pure Chemical Corporation, reagent premium grade

[0157] · Bentonite: Calcium-based bentonite, "Neokunibond" manufactured by KUNIMINE INDUSTRIES CO., LTD., average particle size 32.7 μm

[0158] [Average particle size of swelling agent]

[0159] The average particle size of the swelling agent (bentonite) was measured by using a laser diffraction / scattering particle size distribution measuring apparatus (“LA-960” manufactured by HORIBA, Ltd.) to measure the average particle size (D50) at a cumulative frequency of 50% in the volume-based particle size distribution.

[0160] Silica: Precipitated wet silica, "CARPLEX (registered trademark) #67" manufactured by EVONIC

[0161] Breathable packaging material A: Bag-shaped with outer dimensions of 40 mm x 30 mm

[0162] The air-permeable packaging material A was prepared by using linear low-density polyethylene (porous film, thickness 30 μm, hereinafter simply referred to as “LLDPE”) / tex paper (unit area mass 50 g / m 2 A multilayer sheet (thickness 52 μm, air permeability resistance 5300 seconds) of a polyethylene terephthalate (porous film, thickness 12 μm, hereinafter referred to as “PET”) structure was folded with the LLDPE inside and heat-sealed on three sides with a sealing width of 5 mm with one side as an opening.

[0163] [Breathability resistance of multi-layer sheets]

[0164] The air permeability resistance of the multilayer sheet was measured three times using a digital Oken air permeability tester ("EG02" manufactured by ASAHI SEIKO CO., LTD.), and the arithmetic mean of the obtained results was taken as the measurement result.

[0165] Breathable packaging material B: Bag-shaped with outer dimensions of 100 mm x 70 mm

[0166] The air-permeable packaging material B was prepared as follows: LLDPE (same as above) / foreign paper (weight per unit area 50 g / m 2 ) structure multilayer sheet (thickness 39 μm, air permeability resistance 10 seconds (determination method is the same as above)), folded with LLDPE on the inside, and heat-sealed on three sides with a sealing width of 5 mm with one side as an opening.

[0167] <Production of deoxidizer composition and deoxidizer package using the same>

[0168] (Example 1)

[0169] [1] Preparation of deoxidizer composition

[0170] First, 8.4 g of calcium chloride (CaCl 2 ) as an alkaline earth metal halide was dissolved in 14.8 g of water to prepare a calcium chloride aqueous solution.

[0171] Then, 20.0 g of iron powder, 4.0 g of activated carbon, 0.2 g of calcium hydroxide (Ca(OH)2) as an alkaline substance, and 1.5 g of bentonite as a swelling agent were put into a 300 ml plastic container and shaken to obtain a mixture.

[0172] Next, the previously prepared calcium chloride aqueous solution is added to the above mixture, and further shaken and mixed to obtain a deoxidizer composition.

[0173] The obtained deoxidizer composition was a granular material (average particle size: 1.60 mm) in which powder particles were aggregated.

[0174] [Average particle size of deoxidizer composition]

[0175] The average particle size of the deoxidizer composition is measured by using a laser diffraction / scattering particle size distribution measuring apparatus ("LA-960" manufactured by HORIBA, Ltd.) to measure the average particle size (D50) at a cumulative frequency of 50% in a volume-based particle size distribution.

[0176] [2] Production of deoxidizer packaging

[0177] [2-1] Preparation of deoxidizer package A (sample for measuring oxygen absorption amount)

[0178] The air-permeable packaging material A was filled with 0.8 g of the deoxidizer composition prepared in the above [1], and then the opening was heat-sealed with a sealing width of 5 mm to prepare a bag-type deoxidizer package A.

[0179] It should be noted that the prepared deoxidizer package A was placed in a gas barrier bag with low oxygen permeability (manufactured by Fukusuke Kogyo Co., Ltd., made by laminating barrier nylon and LLDPE) and the opening was heat-sealed to prevent reaction with oxygen in the atmosphere for storage until the oxygen absorption amount was measured.

[0180] [2-2] Preparation of deoxidizer package B (sample for measuring hydrogen generation amount)

[0181] The air-permeable packaging material B was filled with 25 g of the deoxidizer composition prepared in the above [1], and then the opening was heat-sealed with a sealing width of 5 mm to prepare a bag-type deoxidizer package B.

[0182] It should be noted that the prepared deoxidizer package B was placed in a gas barrier bag with low oxygen permeability (manufactured by Fukusuke Kogyo Co., Ltd., made by laminating barrier nylon and LLDPE) and the opening was heat-sealed to prevent reaction with oxygen in the atmosphere for storage until the hydrogen generation amount was measured.

[0183] (Examples 2 to 16 and Comparative Examples 4 and 5)

[0184] In Examples 2 to 16 and Comparative Examples 4 and 5, except that the compounding amounts of the components were changed to the values ​​shown in Table 1, deoxidizer compositions and deoxidizer packages A and B were prepared in the same manner as in Example 1.

[0185] (Comparative Examples 1 to 3)

[0186] In Comparative Examples 1 to 3, except that the compounding amount of each component was changed to the value shown in Table 1, the same method as in Example 1 was used to prepare deoxidizer compositions.

[0187] However, the obtained deoxidizer composition had little activated carbon and was not fully water-retaining, and was in a slurry state. Therefore, the deoxidizer packages A and B were not produced.

[0188] (Comparative Example 6)

[0189] In Comparative Example 6, deoxidizer packages A and B were prepared by the same method as in Example 1, except that the deoxidizer composition was prepared by the following method [1′] instead of the method [1] described above.

[0190] [1'] Preparation of deoxidizer composition

[0191] 8.5 g of calcium chloride (CaCl 2 ) as an alkaline earth metal halide was dissolved in 16.5 g of water to prepare a calcium chloride aqueous solution.

[0192] Next, 10.0 g of silicon dioxide as a water-retaining carrier was placed in a 300 ml plastic container, and the above-mentioned calcium chloride aqueous solution was added and mixed to obtain a water supply agent.

[0193] Next, 50.0 g of iron powder was mixed with the moisture supply agent, and 1.0 g of activated carbon was further added, and the mixture was shaken and mixed in the plastic container to obtain a deoxidizer composition.

[0194] It should be noted that the obtained deoxidizer composition is a granular material formed by aggregation of powder particles (average particle size 0.12 mm, measured by the same method as above).

[0195] (Comparative Example 7)

[0196] In Comparative Example 7, except that the compounding amount of each component was changed to the value shown in Table 1, the deoxidizer composition and deoxidizer packages A and B were prepared by the same method as in Comparative Example 6.

[0197] <Evaluation>

[0198] The following evaluations were performed using the deoxidizer compositions and deoxidizer packages A and B prepared in Examples 1 to 16 and Comparative Examples 4 to 7. The results are shown in Table 1.

[0199] (water activity)

[0200] The water activity was measured by the following method using the deoxidizer composition prepared in the above [1].

[0201] First, 1.0 g of the deoxidizer composition was placed in a dedicated petri dish, and a water activity measuring device ("AquaLab TDL 2" manufactured by METER) was used to measure the water activity at 25°C according to the procedure specified by the device.

[0202] The above measurement was performed three times, and the arithmetic mean of the obtained results was evaluated as the water activity value of the deoxidizer composition of each Example or Comparative Example.

[0203] In this embodiment, the water activity is controlled to be 0.40 or more and 0.60 or less (medium water activity) as good, and the value close to the median, that is, 0.50, is evaluated as better. It should be noted that the water activity values ​​in Table 1 are rounded off to the third decimal place and evaluated.

[0204] (oxygen uptake)

[0205] The oxygen absorption amount was measured by the following method using the deoxidizer package A prepared in the above [2-1].

[0206] First, one deoxidizer package A was placed in a gas barrier bag made of nylon / polyethylene laminate film (manufactured by Fukusuke Kogyo Co., Ltd., size 250 mm×400 mm, oxygen permeability 7.3 ml / m 2 The opening was heat-sealed and sealed at 100 ·day·atm). Furthermore, the oxygen concentration (initial oxygen concentration) in the gas barrier bag at this time was measured.

[0207] Then, the gas barrier bag was quickly placed in a thermostatic chamber at 25°C and kept for 72 hours, and then the oxygen concentration in the gas barrier bag (oxygen concentration after storage) was measured to calculate the oxygen absorption (initial oxygen concentration - oxygen concentration after storage). Furthermore, the calculated oxygen absorption was divided by the mass of the deoxidizer composition (unit: g) to calculate the oxygen absorption per unit mass of the deoxidizer composition (original powder) (unit: ml / original powder 1g).

[0208] It should be noted that the oxygen concentration was measured using a gas analyzer ("Check Mate 3" manufactured by MOCON). The hollow needle at the front end of the sampling silicon tube attached to the gas analyzer was inserted into the bag through a sampling rubber sheet (25 mm × 25 mm, thickness 2 mm) previously attached to the gas barrier bag, and the oxygen concentration in the gas barrier bag was measured.

[0209] The above measurement was performed 3 times, and the arithmetic mean of the obtained results was used as the oxygen absorption of the deoxidizer composition of each embodiment or comparative example and evaluated. The more oxygen absorption, the better the oxygen absorption performance. In this embodiment, the oxygen absorption per unit mass of the deoxidizer composition (original powder) was 85.0 [ml / original powder 1g] or more and was evaluated as good.

[0210] (Hydrogen production)

[0211] The amount of hydrogen generation was measured by the following method using the deoxidizer package B prepared in the above [2-2].

[0212] First, one deoxidizer package B was placed together with 25 ml of air at 35°C in a gas barrier bag made of nylon / aluminum foil / polyethylene laminated film (manufactured by MEIWA PAX Co., Ltd., size 175 mm×250 mm, oxygen permeability 0.1 ml / m 2 ·day·atm or less), the opening is heat-sealed to seal it.

[0213] Then, the gas barrier bag was quickly placed in a thermostatic chamber at 35°C and kept for 72 hours, and then the hydrogen concentration in the gas barrier bag was measured by gas chromatography to calculate the hydrogen generation amount (unit: ml). Furthermore, the calculated hydrogen generation amount was divided by the mass of the deoxidizer composition (unit: g) to calculate the hydrogen generation amount per unit mass of the deoxidizer composition (original powder) (unit: ml / original powder 1g).

[0214] In addition, the hydrogen concentration was measured using a gas chromatograph ("GC-14A" manufactured by Shimadzu Corporation).

[0215] The above measurement was performed 3 times, and the arithmetic mean of the obtained results was used as the hydrogen generation amount of the deoxidizer composition of each embodiment or comparative example and evaluated. The less the hydrogen generation amount, the more effectively the hydrogen generation can be suppressed. In this embodiment, the hydrogen generation amount per unit mass of the deoxidizer composition (original powder) was 0.100 [ml / original powder 1g] or less and was evaluated as good.

[0216] (Amount of hydrogen produced per 100ml of oxygen absorbed)

[0217] The amount of hydrogen generated when absorbing 100 ml of oxygen, i.e., the amount of hydrogen generated per 100 ml of oxygen absorbed (unit: ml / 100 ml of oxygen absorbed) was calculated using the results of the oxygen absorption amount per 1 g of the deoxidizer composition and the hydrogen generation amount per 1 g of the deoxidizer composition calculated by the above method.

[0218] The smaller the amount of hydrogen generated per 100 ml of oxygen absorption, the smaller the amount of hydrogen generated relative to the amount of oxygen absorption required in actual use, and the better. In this embodiment, the amount of hydrogen generated per 100 ml of oxygen absorption was evaluated as good if it was 0.050 [ml / 100 ml of oxygen absorption] or less.

[0219] [Table 1]

[0220]

[0221] As shown in Table 1, it was confirmed that the deoxidizer composition comprising iron powder, activated carbon, water, alkaline earth metal halide and alkaline substance, wherein the iron powder, activated carbon, water and alkaline earth metal halide are in specified contents, exhibited moderate water activity, excellent oxygen absorption performance and low hydrogen generation (Examples 1 to 16).

[0222] On the other hand, when the content of activated carbon relative to iron powder was less than the specified ratio, it was confirmed that the activated carbon acting as a water-retaining carrier did not completely retain water, and the excess water formed a slurry state, so the deoxidizer package could not be produced (Comparative Examples 1 to 3).

[0223] Furthermore, even when the content of activated carbon relative to iron powder was appropriate, when the content of water relative to activated carbon exceeded a predetermined ratio, it was confirmed that the amount of oxygen absorption decreased (Comparative Examples 4 and 5).

[0224] Furthermore, when silica was used instead of activated carbon, it was confirmed that silica acted as a water-retaining carrier and could retain water, thereby obtaining a granular deoxidizer composition, but the oxygen absorption amount was small and the hydrogen generation amount was large (Comparative Examples 6 and 7).

Claims

1. A deoxidizer composition comprising: iron powder, activated carbon, water, a halide of an alkaline earth metal, and an alkaline substance, The content of the activated carbon is 20 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the iron powder. The content of the water is 230 parts by mass or more and 370 parts by mass or less relative to 100 parts by mass of the content of the activated carbon, The content of the alkaline earth metal halide is 50 parts by mass or more and 65 parts by mass or less relative to 100 parts by mass of the water content.

2. The deoxidizer composition according to claim 1, wherein The alkaline earth metal halide is at least one selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide and calcium bromide.

3. The deoxidizer composition according to claim 1 or 2, wherein The alkaline substance is one or more selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, and salts of weak acids and strong bases.

4. The deoxidizer composition according to any one of claims 1 to 3, wherein The alkaline substance is calcium hydroxide. 5 . The deoxidizer composition according to claim 1 , further comprising a swelling agent.

6. The deoxidizer composition according to claim 5, wherein The swelling agent is at least one selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite, and sodium bentonite.

7. The deoxidizer composition according to claim 5 or 6, wherein The content of the swelling agent is 3 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the water content.

8. The deoxidizer composition according to any one of claims 1 to 7, wherein The deoxidizer composition is in granular form.

9. The deoxidizer composition according to any one of claims 1 to 8, wherein The water activity of the deoxidizer composition is greater than or equal to 0.40 and less than or equal to 0.

60.

10. A method for producing a deoxidizer composition, which is a method for producing the deoxidizer composition according to any one of claims 1 to 9, the method comprising: The process of mixing iron powder, activated carbon, water, alkaline earth metal halide and alkaline substance. 11 . An oxygen scavenger package, comprising: the oxygen scavenger composition according to claim 1 , and an air-permeable packaging material containing the oxygen scavenger composition.

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