Deoxidizer composition and method for producing the same, and deoxidizer package

Abstract

To provide a deoxidizer composition with reduced hydrogen evolution and a method for producing the same, and a deoxidizer package.SOLUTION: A deoxidizer composition contains iron powder, metal halide, water, a water-holding carrier and nitrate. The molar ratio of nitrate ions (NO3-) in the nitrate to halide ions (X-) in the metal halide [NO3- / X-] is 0.010 or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an oxygen scavenger composition, a method for producing the same, and an oxygen scavenger package. [Background technology]

[0002] Oxygen scavengers that utilize the oxidation reaction of iron powder (hereinafter, iron-based oxygen scavengers) have been proposed. Commercially available oxygen scavengers (for example, trade name "Ageless" manufactured by Mitsubishi Gas Chemical Co., Ltd.) are sealed together with foods, medicines, and other items in gas barrier containers to remove oxygen from the containers, and are already widely used to maintain the quality and freshness of the items.

[0003] Iron-based oxygen absorbers include "moisture-dependent" oxygen absorbers that start absorbing oxygen by utilizing moisture evaporated from the preserved material, etc., and "self-reacting" oxygen absorbers that already contain the moisture necessary for the oxygen absorption reaction of iron in the oxygen absorber composition. In the case of a "self-reacting" oxygen absorber, a moisture donor (water retention agent) made of a porous material impregnated with moisture is present in the oxygen absorber composition, so that the moisture required for the oxygen absorption reaction of iron can be supplied from the moisture donor to the iron (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-146668 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned "self-reacting type" oxygen absorbers have a problem in that the iron powder in the oxygen absorber reacts with water during storage, transportation, and use, generating hydrogen. Normally, oxygen absorbers are stored in gas barrier bags until they are used so that they do not react with oxygen in the air. If a large amount of hydrogen is generated during storage in this manner, the gas barrier bag may expand and deform, resulting in poor appearance, or poor degassing due to the gas barrier bag not being able to degas properly. In order to solve these problems, there is a demand for an oxygen scavenger composition that generates less hydrogen.

[0006] Therefore, an object of the present invention is to provide an oxygen absorbing composition which generates a small amount of hydrogen, a method for producing the same, and an oxygen absorbing package. [Means for solving the problem]

[0007] That is, the gist of the present invention is as follows. [1] An oxygen scavenger composition comprising iron powder, a metal halide, water, a water-retaining carrier, and a nitrate, The halide ion (X - ) in the nitrate salt (NO3 - ) molar ratio [NO3 - / X - ] is 0.010 or more. [2] The oxygen absorbing composition according to the above [1], wherein the nitrate is one or more selected from the group consisting of sodium nitrate, potassium nitrate and calcium nitrate. [3] The oxygen absorbing composition according to the above [1] or [2], wherein the water-retentive carrier is one or more selected from the group consisting of diatomaceous earth, silica and activated carbon. [4] The oxygen absorbing composition according to any one of the above [1] to [3], wherein the metal halide is at least one selected from the group consisting of sodium chloride, calcium chloride, magnesium chloride, sodium bromide, magnesium bromide and calcium bromide. [5] The oxygen absorbing composition according to any one of the above [1] to [4], wherein the content of the metal halide is 1.25 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the water. [6] The oxygen absorbing composition according to any one of the above [1] to [5], wherein the water content is 140 parts by mass or more and 400 parts by mass or less per 100 parts by mass of the water-retaining carrier. [7] The oxygen absorbing composition according to any one of the above [1] to [6], wherein the content of the water-retaining carrier is 10 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the iron powder. [8] The oxygen absorbing composition according to any one of the above [1] to [7], wherein the content of the nitrate is 0.10 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the iron powder. [9] The oxygen absorbing composition according to any one of the above [1] to [8], further comprising a thickener, the thickener being one or more selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite and sodium bentonite.

[10] The oxygen absorbing composition according to the above [9], wherein the content of the thickener is 5.0 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the water.

[11] The oxygen absorbing composition according to any one of the above [1] to

[10] , wherein the oxygen absorbing composition is in the form of a granule.

[12] A method for producing the oxygen absorbing composition according to any one of the above [1] to

[11] , A method for producing an oxygen scavenger composition, comprising the step of mixing iron powder, a metal halide, water, a water-retentive carrier, and a nitrate.

[13] An oxygen absorber package comprising the oxygen absorber composition according to any one of the above items [1] to

[11] and a breathable packaging material containing the oxygen absorber composition. Effect of the Invention

[0008] According to the present invention, it is possible to provide an oxygen absorbing composition that generates a small amount of hydrogen, a method for producing the same, and an oxygen absorbing package. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Embodiments of the oxygen scavenger composition according to the present invention, its manufacturing method, and the oxygen scavenger package will be described in detail below. In addition, in this specification, the term "A to B" regarding the description of numerical values means "A or more and B or less" (when A < B) or "A or less and B or more" (when A > B). Further, in the present invention, a combination of preferred embodiments is a more preferred embodiment.

[0010] [Oxygen Scavenger Composition] The oxygen scavenger composition of the present invention contains iron powder, a metal halide, water, a water retention carrier, and a nitrate, and the molar ratio [NO3 - / X - of nitrate ions (NO3 - ) in the nitrate to halide ions (X - ) in the metal halide is 0.010 or more.

[0011] Due to the above configuration, the oxygen scavenger composition of the present invention can effectively suppress the generation of hydrogen. Although the reason why the oxygen scavenger composition of the present invention exhibits the above effects is not clear, one possible reason is as follows.

[0012] Generally, in order for iron to absorb oxygen, it is necessary to draw moisture onto the surface of the iron, and for this, the deliquescence phenomenon of metal salts such as metal halides is utilized. However, when there is a high concentration of salt and water on the surface of the iron, there is a problem that pits (holes) are generated and grow due to pitting corrosion. Furthermore, it is considered that the reaction of the following formulas (1) and (2) in the pits causes a problem of hydrogen generation. FeCl2 + H2O → Fe(OH)2 + HCl ···(1) 2H + + 2e - → H2···(2)

[0013] On the other hand, the oxygen scavenger composition of the present invention is characterized by containing a nitrate. By containing a nitrate, nitrate ions (NO3 -Nitrate ions are effective in suppressing the generation and growth of pits and cracks, and can also be used to produce nitrate ions (NO3 - ) is hydrogen ion (2H + ) can be effectively suppressed by reacting with hydrogen. No.3 - +2H + +2e - ⇔NO2 - +H2O (3)

[0014] Each component will be described below. (Iron powder) The oxygen scavenger composition of the present invention contains iron powder. The iron powder in the oxygen scavenger composition of the present invention is the main agent for the oxygen scavenging reaction.

[0015] The iron powder is not particularly limited, but is preferably one with an exposed surface of iron (zero-valent metallic iron), and may have a very thin oxide film like a normal metal surface, as long as it does not impede the effects of the present invention. Specifically, reduced iron powder, electrolytic iron powder, sprayed iron powder (atomized iron powder), etc. can be preferably used. Also, crushed or cut products of cast iron, etc. can be used. The iron powder may be used alone or in combination of two or more kinds as required. In addition, these iron powders are readily available on the market and may also be used.

[0016] 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 even more preferably 300 μm or less from the viewpoint of improving the contact with oxygen, and is preferably 1 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more from the viewpoint of suppressing the generation of dust. Specifically, the average particle size (D50) of the iron powder is preferably 1 to 1000 μm, more preferably 10 to 500 μm, and even more preferably 20 to 300 μm. The iron powder having an average particle size in the above range can be obtained by appropriately selecting a commercially available iron powder, or can be obtained by classifying the iron powder using a sieve according to the desired average particle size. The average particle size of the iron powder can be measured by the method described in the Examples.

[0017] 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 from the viewpoint of suppressing the generation of dust, it is preferably 0.50 m 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. The specific surface area of ​​the iron powder can be measured by the method described in the Examples.

[0018] The content of iron powder is not particularly limited, but is preferably 15% by mass or more and 75% by mass or less, more preferably 20% by mass or more and 60% by mass or less, and even more preferably 25% by mass or more and 50% by mass or less, in the oxygen absorbing composition.

[0019] (Metal Halides) The oxygen scavenger composition of the present invention comprises a metal halide. The metal halide in the oxygen absorbing composition of the present invention is a substance that acts as a catalyst on the oxidation reaction of iron powder, improving the activity of the iron powder. The metal halide also plays a role in preventing the water contained in the oxygen absorbing composition from evaporating and being lost from the oxygen absorbing composition, and exerts an effect of suppressing the transfer of moisture to the preserved object.

[0020] As the metal halide, any commonly known metal halide can be used without any particular limitation. The metal in the metal halide is not particularly limited, and may be, for example, one or more selected from the group consisting of alkali metals, alkaline earth metals, copper, zinc, aluminum, tin, iron, cobalt, and nickel. Among them, one or more selected from the group consisting of alkali metals, alkaline earth metals, and iron are preferred, and one or more selected from the group consisting of lithium, potassium, sodium, magnesium, calcium, barium, and iron are more preferred. In addition, the halide in the metal halide is not particularly limited, and may be, for example, chloride, bromide, and iodide.

[0021] Among these, from the viewpoints of ease of handling, safety, and the like, the metal halide is preferably at least one selected from the group consisting of sodium chloride, calcium chloride, magnesium chloride, sodium bromide, magnesium bromide, and calcium bromide. In addition, from the viewpoints that it has high solubility in water and its water activity can be easily reduced, and is suitable for preparing an oxygen scavenger composition (bulk powder) with a medium water activity, preferably it is one or more selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide and calcium bromide, more preferably it is one or more selected from the group consisting of calcium chloride and magnesium chloride, and even more preferably it is calcium chloride. The metal halides can be used alone or in combination of two or more kinds as required. In addition, these metal halides are readily available commercially and can be used.

[0022] The metal halide is preferably contained in the oxygen absorber composition as an aqueous solution dissolved in water. When the metal halide is used as a raw material in the form of an aqueous solution, the concentration of the metal halide is preferably 5% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 50% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less. The metal halide concentration of 5% by mass or more can prevent the catalytic effect of iron oxidation from decreasing, and the metal halide concentration of 60% by mass or less can prevent the vapor pressure of moisture from decreasing, and can prevent the amount of oxygen absorbed from decreasing due to insufficient moisture being supplied to iron.

[0023] The content of the metal halide is not particularly limited, but is preferably 1.25 parts by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 80 parts by mass or less, even more preferably 10 parts by mass or more and 60 parts by mass or less, and even more preferably 20 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the water content. By setting it within the above range, an oxygen scavenger composition having excellent oxygen absorption performance and generating a small amount of hydrogen can be obtained. The content of the metal halide in the oxygen scavenger composition is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 20% by mass. Furthermore, the content of the metal halide relative to 100 parts by mass of the iron powder is preferably 5 to 70 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 30 to 50 parts by mass.

[0024] (water) The oxygen scavenger composition of the present invention comprises water. Water contained in the oxygen scavenger composition of the present invention is a component necessary for promoting the oxygen scavenging reaction.

[0025] The water content is not particularly limited, but is preferably 140 parts by mass or more and 400 parts by mass or less, more preferably 200 parts by mass or more and 400 parts by mass or less, and even more preferably 300 parts by mass or more and 350 parts by mass or less, relative to 100 parts by mass of the water-retaining carrier. By setting the water content within the above range, an oxygen absorbing composition having excellent oxygen absorption performance and generating a small amount of hydrogen can be obtained. The water content in the oxygen scavenger composition is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 40% by mass, and even more preferably 20% by mass to 35% by mass. Furthermore, the water content is preferably 50 parts by mass to 120 parts by mass, more preferably 60 parts by mass to 100 parts by mass, and even more preferably 70 parts by mass to 90 parts by mass, relative to 100 parts by mass of the iron powder.

[0026] (Water Retaining Carrier) The oxygen scavenger composition of the present invention includes a water-retentive carrier. The water-retentive carrier in the oxygen absorbing composition of the present invention is capable of carrying (holding) water by being impregnated therein, and plays a role of supplying the carried water to the surroundings, particularly to the iron powder, as required.

[0027] Such a water-retentive carrier is not particularly limited as long as it can retain water, but is preferably one or more selected from the group consisting of porous substances and highly water-absorbent polymers, and more preferably a porous substance. The porous substance may be any substance having a porous structure and a water-retaining function, and examples thereof include diatomaceous earth, zeolite, sepiolite, cristobalite, porous glass, silica, activated clay, acid clay, activated carbon, vermiculite, wood flour, etc. Among them, one or more selected from the group consisting of diatomaceous earth, silica, and activated carbon are preferred. In particular, activated carbon is more preferable because it has a function of promoting the oxidation reaction of iron in addition to a water retention function. The type of activated carbon is not particularly limited, and the raw material may be wood, coconut shell, coal, etc., but from the viewpoint of using the oxygen scavenger composition of the present invention for food, one or more types selected from wood and coconut shell are preferable. Furthermore, the superabsorbent resin may be any resin that can solidify liquids such as water into a gel, and examples of such resins include polyacrylate-based resins, polysulfonate-based resins, polyacrylamide-based resins, polyvinyl alcohol-based resins, starch-based resins, cellulose-based resins, and polyalginic acid-based resins. The above-mentioned water-retentive carriers can be used alone or in combination of two or more kinds as necessary. In addition, these water-retentive carriers are commercially available and can be used. From the viewpoint of further enhancing the water retention function, the water-retaining carrier is preferably one or more selected from the group consisting of diatomaceous earth, silica, and activated carbon, and more preferably one or more selected from the group consisting of activated carbon, diatomaceous earth, and silica.

[0028] The properties of the water-retaining carrier are not particularly limited, but from the viewpoint of ease of handling during the production of the oxygen absorbing composition, a powder-like carrier with high fluidity is preferably used, and the particle shape of the water-retaining agent is more preferably nearly spherical.

[0029] From the viewpoint of ease of handling during production of the oxygen scavenger composition, the average particle size of the water-retentive carrier is preferably 0.05 μm or more and 1000 μm or less, more preferably 0.1 μm or more and 100 μm or less, in the case of a powder form. In particular, when the water-retentive carrier is activated carbon, the particle size is more preferably 1 μm or more and 100 μm or less, and even more preferably 1 μm or more and 50 μm or less. Furthermore, when the water-retentive carrier is diatomaceous earth, the particle size is more preferably 0.2 μm or more and 50 μm or less, and even more preferably 0.2 μm or more and 10 μm or less. The particles of the water-retaining carrier can be primary particles, aggregated particles, or granulated particles as long as they have a particle size within the above range. The water-retaining carrier having a particle size within the above range can be used alone, or multiple types having different particle sizes can be mixed in any ratio. Such water-retaining carriers are readily available commercially and can be used. The average particle size of the activated carbon can be measured by the method described in the Examples.

[0030] The content of the water-retaining carrier is not particularly limited, but is preferably 10 parts by mass or more and 40 parts by mass or less, more preferably 15 parts by mass or more and 35 parts by mass or less, and even more preferably 20 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the iron powder content. By setting it within the above range, an oxygen absorbing composition having excellent oxygen absorption performance and generating a small amount of hydrogen can be obtained. The content of the water-retaining carrier in the oxygen scavenger composition is preferably from 1% by mass to 40% by mass, more preferably from 2% by mass to 20% by mass, and even more preferably from 5% by mass to 15% by mass.

[0031] (nitrate) The oxygen scavenger composition of the present invention comprises a nitrate salt. The nitrate in the oxygen scavenger composition of the present invention binds nitrate ions (NO3 - Nitrate ions suppress the generation, growth and cracking of pits on the surface of the iron powder due to pitting corrosion, and furthermore, they can reduce the hydrogen ion concentration in the reaction water during the oxygen absorption reaction, and are thought to be able to effectively suppress the generation of hydrogen due to the reduction of hydrogen ions by iron.

[0032] As the nitrate, any commonly known nitrate can be used without any particular limitation. The metal in the nitrate is not particularly limited, and examples thereof include at least one selected from the group consisting of alkali metals, alkaline earth metals, copper, zinc, aluminum, tin, iron, cobalt, and nickel. Among these, at least one selected from the group consisting of alkali metals, alkaline earth metals, and iron is preferred, and at least one selected from the group consisting of lithium, potassium, sodium, magnesium, calcium, barium, and iron is more preferred. The nitrate may be ammonium nitrate.

[0033] Among these, from the viewpoint of effectively suppressing hydrogen generation and from the viewpoint of ease of handling, the nitrate is preferably one or more selected from the group consisting of sodium nitrate, potassium nitrate, and calcium nitrate, more preferably one or more selected from the group consisting of potassium nitrate and sodium nitrate, and even more preferably sodium nitrate. The nitrates can be used alone or in combination of two or more as required. These nitrates are readily available commercially and can also be used.

[0034] Usually, halide ions (X - The higher the content of nitrate ions (NO3 - ) and the halide ions (X - ) to a predetermined relationship, the hydrogen generation suppression ability can be sufficiently exhibited. That is, the halide ion (X - ) to the nitrate ion (NO3 - ) molar ratio [NO3 - / X - From the viewpoint of fully exerting the hydrogen generation suppression ability, it is 0.010 or more, preferably 0.030 or more, more preferably 0.040 or more, even more preferably 0.050 or more, and even more preferably 0.060 or more, and from the viewpoint of enhancing the oxygen absorption ability, it is preferably 1.30 or less, more preferably 0.90 or less, even more preferably 0.75 or less, even more preferably 0.60 or less, and even more preferably 0.50 or less. Specifically, it is preferably 0.010 or more and 1.30 or less, more preferably 0.030 or more and 0.90 or less, even more preferably 0.040 or more and 0.75 or less, even more preferably 0.050 or more and 0.60 or less, and even more preferably 0.060 or more and 0.50 or less.

[0035] In addition, in the present invention, the nitrate ion (NO3 -It is believed that by controlling the amount of hydrogen generated by the catalyst and water (HO) in a predetermined relationship, the equilibrium reaction of the above formula (3) can be shifted to the right, thereby improving the ability to suppress hydrogen generation. That is, the ratio of nitrate ions (NO3 - ) molar ratio [NO3 - / H2O] is preferably 0.001 or more and 0.20 or less, more preferably 0.005 or more and 0.15 or less, and even more preferably 0.010 or more and 0.090 or less. By setting it in the above range, an oxygen absorbing composition that is excellent in oxygen absorption performance and generates a small amount of hydrogen can be obtained.

[0036] The content of the nitrate in the oxygen scavenger composition is preferably 0.10% by mass to 40% by mass, more preferably 0.25% by mass to 25% by mass, and even more preferably 1.0% by mass to 20% by mass. Furthermore, the content of the nitrate relative to 100 parts by mass of the iron powder is preferably 0.10 parts by mass to 100 parts by mass, more preferably 0.60 parts by mass to 90 parts by mass, and even more preferably 2.5 parts by mass to 55 parts by mass. By setting the content within the above range, an oxygen scavenger composition having excellent oxygen absorption performance and generating a small amount of hydrogen can be obtained.

[0037] (Thickener) The oxygen scavenger composition of the present invention preferably further comprises a thickener. The thickener in the oxygen absorbing composition of the present invention is a substance that swells with moisture and has a binding function for maintaining the shape of the granulated material, and specifically, it plays a role of increasing the viscosity of the solution by dissolving or dispersing in a liquid such as an aqueous solution. The thickener is preferably used in a substantially dry state or in a semi-swollen or swollen state having absorbed a small amount to a necessary amount of water.

[0038] Such a thickener is not particularly limited as long as it has a binding function. For example, in addition to known swelling agents that have been used in foods, etc., binding agents, adhesives, binders, etc. can also be used. The thickener may be either an inorganic thickener or an organic thickener. Examples of inorganic thickeners include clay minerals such as sodium bentonite, calcium bentonite, and sodium montmorillonite. Clay minerals are preferred because they are inexpensive and have excellent performance. In particular, clay minerals are also known as inorganic soaps and have a function as a lubricant, and clay minerals swollen with water are known to exhibit high thixotropy and excellent caking properties. Among them, bentonites such as calcium bentonite and sodium bentonite are preferred from the viewpoint of inexpensiveness and strong caking power. Examples of organic thickeners include organic bentonite, natural products such as defatted frozen tofu, agar, starch, dextrin, gum arabic, gelatin, and casein, semi-synthetic products such as crystalline cellulose, carboxymethylcellulose, sodium carboxymethylcellulose, calcium carboxymethylcellulose, hydroxyethylcellulose, lignin sulfonic acid, and hydroxyethylated starch, and synthetic products such as water-insoluble polyvinyl alcohol and polyvinyl methyl ether. Among these, cellulose-based semi-synthetic products such as crystalline cellulose, carboxymethylcellulose, sodium carboxymethylcellulose, calcium carboxymethylcellulose, and hydroxyethylcellulose are preferred from the viewpoint of exhibiting excellent swelling properties, and carboxymethylcellulose, sodium carboxymethylcellulose, and calcium carboxymethylcellulose are preferred from the viewpoint of being inexpensive and having a strong caking force. The above-mentioned thickeners can be used alone or in combination of two or more kinds as necessary. In addition, these thickeners are commercially available and can be used.

[0039] The thickener is preferably one or more selected from the group consisting of clay minerals and cellulose-based semi-synthetic products, and from the viewpoint of low cost and strong caking power, it is more preferably one or more selected from the group consisting of bentonites and cellulose-based semi-synthetic products. More specifically, the thickener is preferably one or more selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite, and sodium bentonite, and more preferably calcium bentonite. The above-mentioned thickeners may be used alone or in combination of two or more kinds, if necessary. Furthermore, these thickeners may be commercially available products.

[0040] The average particle size of the thickener is preferably from 1 μm to 100 μm, more preferably from 5 μm to 50 μm, and even more preferably from 10 μm to 50 μm, from the viewpoint of suppressing dust generation and from the viewpoint of binding function. The average particle size of the thickener can be measured by the method described in the Examples.

[0041] The content of the thickener is not particularly limited, but is preferably 5.0 parts by mass or more and 15 parts by mass or less, more preferably 7.0 parts by mass or more and 12 parts by mass or less, and even more preferably 8.0 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the water content. By setting it within the above range, an oxygen absorbing composition having excellent oxygen absorption performance and generating a small amount of hydrogen can be obtained. The content of the thickener in the oxygen scavenger composition is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass. Furthermore, the content of the thickener is preferably 1 to 20 parts by mass, more preferably 5 to 10 parts by mass, per 100 parts by mass of the iron powder.

[0042] (Other ingredients) In addition to the above components, the oxygen scavenger composition of the present invention may contain other components as necessary, such as a flow improver, a catalyst, an odor absorbent, and a heat dispersant.

[0043] <Shape of oxygen scavenger composition> The shape of the oxygen scavenger composition of the present invention is not particularly limited, but is preferably granular. Here, the particulate matter may be either an agglomerated particle or a granulated material. Examples of the particle shape include spherical, approximately spherical, elliptical, and cylindrical. Since they tend to have better packing properties and higher bulk density, spherical and approximately spherical shapes are preferred, and spherical shapes are more preferred.

[0044] The average particle size of the oxygen absorber composition of the present invention is not particularly limited, but is preferably 0.3 mm or more and 5.0 mm or less, more preferably 0.5 mm or more and 2.0 mm or less. The average particle size of 0.3 mm or more suppresses adhesion to the powder contact part of the packaging machine during filling and packaging due to static electricity, etc., and the average particle size of 5.0 mm or less suppresses the gap between particles from becoming too large, thereby suppressing the decrease in the oxygen absorption amount per unit volume. In order to obtain an oxygen absorber composition having an average particle size in the above range, for example, sieving may be performed using sieves with openings of 0.3 mm and 5.0 mm. The average particle size of the oxygen absorbing composition can be measured by the method described in the Examples.

[0045] <Characteristics of the oxygen scavenger composition> The oxygen scavenger composition of the present invention preferably exhibits a medium water activity. The water activity value closer to 1 means that the water vapor pressure of the water evaporating from the oxygen absorbing composition is closer to the water vapor pressure of pure water. The water activity of the oxygen scavenger composition of the present invention is preferably from 0.40 to 0.60, more preferably from 0.45 to 0.60, and even more preferably from 0.47 to 0.59, which is what is called a medium water activity. 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 meter.

[0046] 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 oxygen absorbing composition, the more likely moisture migration occurs. Therefore, from the viewpoint of suppressing moisture migration, it is preferable that the water activity of the oxygen absorbing composition is the same as that of the article to be stored. The oxygen scavenger composition of the present invention is suitably used for preserving objects exhibiting a medium water activity.

[0047] Examples of preserved items suitable for the oxygen scavenger composition of the present invention include food products such as rice, miscellaneous grains, spices, dried bonito flakes, boiled dried fish, and seaweed, industrial products such as electronic parts with soldered joints, metal screws, and metal blades such as razors, pharmaceuticals such as tableted tablets, herbal medicines, and raw pharmaceutical ingredients that may be hydrolyzed, and various other items. Among these, it is suitable for preserving pharmaceuticals.

[0048] [Method of manufacturing the oxygen scavenger composition] The method for producing the oxygen scavenger composition of the present invention is not particularly limited, but preferably includes a step of mixing iron powder, metal halide, water, a water-retentive carrier, and a nitrate. According to this manufacturing method, the iron powder, metal halide, water, water-retaining carrier, and nitrate are mixed until uniformly dispersed to prepare a granular material, and the oxygen absorbing composition can be efficiently prepared.

[0049] The mixing step may be (1) a step of mixing all the components at once, (2) a step of preparing an aqueous solution in which a metal halide is dissolved in water, and adding the aqueous solution to a homogeneous mixture of iron powder, a water-retaining carrier, a nitrate, and optionally a swelling agent and other components, and mixing the aqueous solution, or (3) a step of preparing an aqueous solution in which a metal halide and a nitrate are dissolved in water, and adding the aqueous solution to a homogeneous mixture of iron powder, a water-retaining carrier, and optionally a swelling agent and other components, and mixing the aqueous solution. From the viewpoint of obtaining a more homogeneous oxygen scavenger composition, the above step (2) or (3) is preferable. In addition, in the case of (3), the metal halide and the nitrate may react in the aqueous solution, and the concentration of the metal halide may change. Therefore, from the viewpoint of adding and mixing the metal halide to the iron powder or the like as an aqueous solution prepared to a desired concentration, the above step (2) is more preferable.

[0050] The mixing method is not particularly limited, and may be shaking mixing, mixing with a mixer, etc. Specific examples of the mixer include a Nauta mixer (manufactured by Hosokawa Micron Corporation), a conical mixer (manufactured by Ohno Chemical Machinery Co., Ltd.), a vertical granulator (manufactured by Powrex Corporation), a high-speed mixer (manufactured by EarthTechnica Corporation), and a granulator (manufactured by Akira Kiko Co., Ltd.).

[0051] Since the iron powder, which is the main ingredient of the oxygen scavenger, reacts with oxygen, the reaction with oxygen proceeds gradually even in the absence of water, metal halide, etc. Therefore, it is preferable to carry out the mixing in an inert atmosphere (in the case of a substantially sealed system, the system is usually filled with an oxygen-free inert gas (e.g., N2) atmosphere) and to take appropriate measures to remove heat.

[0052] [Oxygen absorber packaging] The oxygen absorber package of the present invention comprises the oxygen absorber composition described above and a breathable packaging material containing the oxygen absorber composition.

[0053] (packaging material) Examples of packaging materials include those formed by bonding two sheets of breathable packaging material together to form a bag, those formed by bonding one sheet of breathable packaging material with one sheet of non-breathable packaging material to form a bag, and those formed by folding one sheet of breathable packaging material and sealing the edges together except for the folded part to form a bag.

[0054] Here, when the breathable packaging material and the non-breathable packaging material are rectangular, the packaging material may be one in which two sheets of breathable packaging material are overlapped and the four sides are heat-sealed to form a bag, one sheet of breathable packaging material and one sheet of non-breathable packaging material are overlapped and the four sides are heat-sealed to form a bag, or one sheet of breathable packaging material is folded and three sides excluding the folded part are heat-sealed to form a bag. The packaging material may also be one in which the breathable packaging material is shaped into a cylinder and both ends and the body of the cylinder are heat-sealed to form a bag.

[0055] (Breathable packaging materials) As the breathable packaging material, a packaging material that allows oxygen and carbon dioxide to pass through is selected. Among them, a material having an air resistance measured by the Oken type testing machine method of preferably 40,000 seconds or less, more preferably 30,000 seconds or less, even more preferably 20,000 seconds or less, even more preferably 10,000 seconds or less, and preferably 500 seconds or more, more preferably 1000 seconds or more is preferably used. Here, the air resistance refers to a value measured by the method of JIS P8117:2009. More specifically, it can be measured by the method described in the examples.

[0056] As the breathable packaging material, in addition to paper and nonwoven fabric, a plastic film with breathability can be used. As the plastic film, for example, a laminated film formed by laminating and bonding a film of polyethylene terephthalate, polyamide, polypropylene, polycarbonate, etc., and a film of polyethylene, ionomer, polybutadiene, ethylene acrylic acid copolymer, ethylene methacrylic acid copolymer, ethylene vinyl acetate copolymer, etc. as a sealing layer can be used. These laminates can also be used as breathable packaging materials.

[0057] As a method for imparting breathability, various methods can be adopted, including perforation processing using a cold needle or a hot needle. When perforation processing is used to impart breathability, the breathability can be freely adjusted by the diameter, number, material, etc. of the holes to be perforated.

[0058] The thickness of the laminated film is preferably 30 μm to 300 μm, more preferably 40 μm to 250 μm, in which case the film can be a packaging material that retains strength and has excellent heat sealability and packaging suitability, compared to a thickness outside the above range.

[0059] (Applications of oxygen absorber packaging) The oxygen absorber package of the present invention contains the oxygen absorber composition of the present invention, and therefore exhibits medium water activity, has excellent oxygen absorption performance, and generates a small amount of hydrogen. Therefore, it is suitable for preserving objects exhibiting medium water activity. Specifically, the oxygen absorber package of the present invention is preferably used in a method for deoxidizing the space inside a gas barrier container that contains a preserved object exhibiting a medium water activity. According to such a method, it is possible to suppress the transfer of moisture from the oxygen absorber package to the preserved object, and further to efficiently deoxidize the space inside the gas barrier container, thereby maintaining the quality of the preserved object in a good condition.

[0060] In addition, when the oxygen absorber package of the present invention is used, it is preferable to use a package including the oxygen absorber package, a preserved object, and a gas barrier container for containing them. In this case, the humidity of the space inside the gas barrier container is preferably 40% RH or more and 60% RH or less from the viewpoint of maintaining the quality of the preserved object. In addition, the preserved object is preferably one or more selected from food, industrial products, and pharmaceuticals, more preferably pharmaceuticals.

[0061] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and includes all aspects encompassed by the concept of the present invention and the scope of the claims, and can be modified in various ways within the scope of the present invention. EXAMPLES

[0062] The present embodiment will be described in detail below using examples and comparative examples, but the present embodiment can be modified as appropriate as long as the effects of the present invention are achieved.

[0063] <Material> The materials used in the examples and comparative examples are shown below. Iron powder: average particle size 100μm, specific surface area 0.104m 2 / g Calcium chloride (CaCl2): Fujifilm Wako Pure Chemical Industries, Ltd., special grade reagent Hydrated activated carbon: Futamura Chemical Co., Ltd. "S-W50", powder form, average particle size 10 μm, moisture content 50% by mass Calcium bentonite: "Neokunibond" manufactured by Kunimine Kogyo Co., Ltd., average particle size 32.7 μm, hereafter referred to as "bentonite." Sodium nitrate (NaNO3): Fujifilm Wako Pure Chemical Industries, special grade reagent Breathable packaging material A: Bag-shaped with outer dimensions of 40mm x 30mm The breathable packaging material A is a linear low-density polyethylene (perforated film, thickness 30 μm, hereinafter referred to simply as "LLDPE") / foreign paper (basis weight 50 g / m 2 A multilayer sheet (thickness 52 μm, air resistance 5,300 seconds) consisting of LLDPE / polyethylene terephthalate (perforated film, thickness 12 μm, hereafter referred to as "PET") was folded so that the LLDPE was on the inside, and three sides were heat sealed with a seal width of 5 mm so that one side would be an opening. Breathable packaging material B: Bag-shaped with outer dimensions of 100mm x 70mm Breathable packaging material B was produced by folding a multilayer sheet (thickness 39 μm, air resistance 10 seconds) made of LLDPE (same as above) / paper (same as above) so that the LLDPE was on the inside, and heat sealing three sides with a seal width of 5 mm so that one side would be an opening.

[0064] <Measurement method> The above physical properties were measured by the following methods. [Measuring the average particle size of iron powder] The average particle size of the above iron powder was measured using a standard sieve conforming to ISO 3310-1:2000 (equivalent to JIS Z8801-1:2006) and was determined as the average particle size at a cumulative frequency of 50% (D50) from the weight fraction based on the size of the sieve openings after vibrating for 5 minutes. [Specific surface area of ​​iron powder] The specific surface area of ​​the above iron powder (unit: m 2 / g) was measured based on the BET multipoint method in accordance with JIS Z8830:2013. [Average particle size of components other than iron powder] The average particle size of components other than iron powder was measured using a laser diffraction / scattering particle size distribution analyzer (HORIBA, Ltd., "LA-960") as the average particle size at 50% cumulative frequency (D50) in the volumetric particle size distribution. [Air permeability resistance of multi-layer sheet] 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.) The arithmetic mean value of the obtained results was recorded as the measurement result.

[0065] <Oxygen Absorber Composition and Preparation of Oxygen Absorber Package Using the Same> Example 1 [1] Preparation of oxygen scavenger composition First, 18.0 g of calcium chloride (CaCl2) as a metal halide was dissolved in 23.1 g of water to prepare an aqueous calcium chloride solution (calcium chloride 43.7% by mass). Next, 40.0 g of iron powder, 20.0 g of activated carbon in the form of hydrated activated carbon as a water-retaining carrier, 3.0 g of bentonite as a thickener, and 2.75 g of sodium nitrate (NaNO3) were placed in a 300 ml plastic container and shaken to mix, obtaining a mixture. Next, a previously prepared aqueous calcium chloride solution was added to the above mixture, and the mixture was further mixed by shaking to obtain an oxygen scavenger composition. The obtained oxygen absorbing composition was in the form of granules (average particle size: 1.60 mm) that resembled an agglomeration of powder particles.

[0066] [Average particle size of oxygen scavenger composition] The average particle size of the oxygen absorbing composition was measured by a laser diffraction / scattering type particle size distribution measuring device (same as above) as the average particle size at 50% cumulative frequency (D50) in the volume-based particle size distribution.

[0067] [2] Preparation of oxygen absorber packaging [2-1] Preparation of oxygen absorber package A (sample for measuring oxygen absorption amount) 0.8 g of the oxygen absorber composition prepared in [1] above was filled into the breathable packaging material A, and the opening was then heat sealed with a seal width of 5 mm to prepare a small pouch-shaped oxygen absorber package A. The prepared oxygen absorber package A was stored in a gas barrier bag with low oxygen permeability (manufactured by Fukusuke Kogyo Co., Ltd., laminated with barrier nylon and LLDPE) with the opening heat-sealed to prevent reaction with oxygen in the air until it was used to measure the amount of oxygen absorbed.

[0068] [2-2] Preparation of oxygen absorber package B (sample for measuring hydrogen generation amount) After filling the breathable packaging material B with 30 g of the oxygen absorber composition prepared in [1] above, the opening was heat sealed with a seal width of 5 mm to prepare a bag-shaped oxygen absorber package B. The prepared oxygen absorber package B was stored in a gas barrier bag (same as above) with low oxygen permeability, with the opening heat-sealed to prevent reaction with oxygen in the air, until it was used to measure the amount of hydrogen generated.

[0069] Comparative Example 1 In Comparative Example 1, an oxygen absorbing agent composition and oxygen absorbing agent packages A and B were prepared in the same manner as in Example 1, except that sodium nitrate (NaNO3) was not used.

[0070] (Examples 2 to 13 and Comparative Examples 2 and 3) In Examples 2 to 13 and Comparative Examples 2 and 3, oxygen absorber compositions and oxygen absorber packages A and B were prepared in the same manner as in Example 1, except that the amount of sodium nitrate (NaNO3) was changed to the value shown in Table 1.

[0071] <Evaluation> The following evaluations were carried out using the oxygen absorber compositions and oxygen absorber packages A and B prepared in Examples 1 to 13 and Comparative Examples 1 to 3. The results are shown in Table 1.

[0072] (oxygen absorption) The amount of oxygen absorbed was measured by the following method using the oxygen absorber package A prepared in [2-1] above. First, one oxygen absorber package A was placed together with 1,500 ml of air at 25°C in a gas barrier bag made of nylon / polyethylene laminate film (manufactured by Fukusuke Kogyo Co., Ltd., dimensions 250 mm x 400 mm, oxygen permeability 7.3 ml / m 2 The opening was then heat sealed. Furthermore, the oxygen concentration (initial oxygen concentration) inside the gas barrier bag was measured. The gas barrier bag was then immediately placed in a thermostatic chamber at 25°C and held for 7 days, after which the oxygen concentration in the gas barrier bag (oxygen concentration after storage) was measured and the oxygen absorption amount (initial oxygen concentration - oxygen concentration after storage) was calculated. The calculated oxygen absorption amount was then divided by the mass (unit: g) of the iron powder in the oxygen scavenger composition to calculate the oxygen absorption amount per unit mass of iron powder (unit: ml / g of iron powder) at each time point. The oxygen concentration was measured using a gas analyzer (MOCON's "Check Mate 3") by inserting a hollow needle at the tip of a sampling silicon tube attached to the gas analyzer into the bag through a sampling rubber sheet (25 mm x 25 mm, 2 mm thick) that had been attached to the gas barrier bag in advance, and measuring the oxygen concentration inside the gas barrier bag. The above measurements were carried out three times at each time point, and the average value was evaluated as the oxygen absorption amount of the oxygen absorber composition of each Example or Comparative Example. The larger the oxygen absorption amount, the better the oxygen absorption performance. In this Example, the oxygen absorption amount per unit mass of iron powder of 140 ml / 1 g or more was evaluated as good, 160 ml / 1 g or more was evaluated as better, and 200 ml / 1 g or more was evaluated as even better.

[0073] (Amount of hydrogen generated) The amount of hydrogen generated was measured by the following method using the oxygen absorber package B prepared in [2-2] above. First, one oxygen absorber package B was placed together with 25 ml of 35°C air in a gas barrier bag made of nylon / aluminum foil / polyethylene laminate film (manufactured by Meiwa Packs, dimensions 175 mm x 250 mm, oxygen permeability 0.1 ml / m 2The container was stored in a temperature range of 100 °C (100 °F) or less (100 °C per day atm) and the opening was heat sealed. The gas barrier bag was then immediately placed in a thermostatic chamber at 35° C. and held there for 72 hours, after which the hydrogen concentration in the gas barrier bag was measured by gas chromatography and the amount of hydrogen generated (unit: ml) was calculated. The hydrogen concentration was measured using a gas chromatograph ("GC-14A" manufactured by Shimadzu Corporation). The above measurement was carried out three times, and the arithmetic mean value of the obtained results was evaluated as the amount of hydrogen generated for each example or comparative example of the oxygen scavenger composition. The smaller the amount of hydrogen generated, the more effectively hydrogen generation was suppressed. In this example, the amount of hydrogen generated was evaluated as good when it was 1.0 ml or less, better when it was 0.15 ml or less, and even better when it was 0.05 ml or less.

[0074] [Table 1]

[0075] The blending compositions of the oxygen scavenger compositions prepared in Examples 1 to 13 and Comparative Examples 1 to 3 are shown in Table 2 below.

[0076] [Table 2]

[0077] As shown in Table 1, the composition contains iron powder, metal halide, water, a water carrier, and nitrate. The halide ions (X - ) in the nitrate salt (NO3 - ) molar ratio [NO3 - / X - It was confirmed that the oxygen absorbing composition having a value of 0.010 or more has excellent oxygen absorbing performance and generates a small amount of hydrogen (Examples 1 to 13).

[0078] On the other hand, the halide ions (X - ) in the nitrate salt (NO3 -) molar ratio [NO3 - / X - It was confirmed that when the value of [Ratio of Hydrogen Generation Suppression to the Total Hydrogen Generation] is less than 0.010, the hydrogen generation suppression effect is not sufficiently exhibited (Comparative Examples 1 to 3).

Claims

1. An oxygen scavenger composition comprising iron powder, a metal halide, water, a water-retaining carrier, and a nitrate, The halide ions (X － nitrate ions (NO ３ － ) molar ratio [NO ３ － / X － ] is 0.010 or more.

2. 2. The oxygen scavenger composition according to claim 1, wherein the nitrate is at least one selected from the group consisting of sodium nitrate, potassium nitrate, and calcium nitrate.

3. 2. The oxygen absorbing composition according to claim 1, wherein the water-retaining carrier is at least one selected from the group consisting of diatomaceous earth, silica, and activated carbon.

4. 2. The oxygen scavenger composition according to claim 1, wherein the metal halide is at least one selected from the group consisting of sodium chloride, calcium chloride, magnesium chloride, sodium bromide, magnesium bromide, and calcium bromide.

5. 2. The oxygen absorbing composition according to claim 1, wherein the content of the metal halide is 1.25 parts by mass or more and 100 parts by mass or less per 100 parts by mass of water.

6. 2. The oxygen absorber composition according to claim 1, wherein the content of the water is 140 parts by mass or more and 400 parts by mass or less per 100 parts by mass of the water-retaining carrier.

7. 2. The oxygen absorber composition according to claim 1, wherein the content of the water-retaining carrier is 10 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the iron powder.

8. 2. The oxygen absorbing composition according to claim 1, wherein the content of the nitrate is 0.10 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the iron powder.

9. 2. The oxygen scavenger composition according to claim 1, further comprising a thickener, wherein the thickener is at least one selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite, and sodium bentonite.

10. 10. The oxygen absorber composition according to claim 9, wherein the content of the thickener is 5.0 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the water.

11. 10. The oxygen scavenger composition of claim 1, wherein the oxygen scavenger composition is granular.

12. A method for producing the oxygen scavenger composition according to any one of claims 1 to 11, comprising: A method for producing an oxygen scavenger composition, comprising the step of mixing iron powder, a metal halide, water, a water-retaining carrier, and a nitrate.

13. An oxygen absorber package comprising the oxygen absorber composition according to any one of claims 1 to 11 and a breathable packaging material containing the oxygen absorber composition.