阅读说明：本技术 脱氧剂组合物及其制造方法 (Oxygen scavenger composition and method for producing same ) 是由 佐藤大挥 井上敦 于 2020-05-19 设计创作，主要内容包括：一种脱氧剂组合物,其包含含有保水剂、溶胀剂、金属盐、水和铁的组合物的混合造粒物,以及一种脱氧剂组合物的制造方法,其包括将保水剂、溶胀剂、金属盐、水和铁一起混合来造粒的工序。(A deoxidizer composition comprising a mixed granulated product of a composition containing a water-retaining agent, a swelling agent, a metal salt, water and iron, and a method for producing the deoxidizer composition, which comprises a step of mixing and granulating the water-retaining agent, the swelling agent, the metal salt, water and iron together.)

1. A deoxidizer composition comprising a mixed granulated substance of a composition containing a water retaining agent, a swelling agent, a metal salt, water and iron.

2. The oxygen scavenger composition according to claim 1, wherein the average particle diameter is 0.3mm or more and 5.0mm or less.

3. The oxygen scavenger composition according to claim 1 or 2, wherein a layer containing a porous carrier is provided on the outer side of the mixed granulated substance.

4. The oxygen scavenger composition according to any one of claims 1 to 3, wherein the water retaining agent contains at least one selected from the group consisting of diatomaceous earth, silica and activated carbon.

5. The oxygen absorbent composition according to any one of claims 1 to 4, wherein the swelling agent contains at least one selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite and sodium bentonite.

6. The oxygen scavenger composition according to any one of claims 1 to 5, wherein the mixed granulated substance is not a press-molded substance.

7. The oxygen scavenger composition according to any one of claims 1 to 6, wherein iron is dispersed throughout the mixed granules.

8. A method for producing the oxygen scavenger composition according to any one of claims 1 to 7, which comprises a step of mixing together a water retaining agent, a swelling agent, a metal salt, water and iron, and granulating the mixture.

9. A deoxidizer package comprising the deoxidizer composition of any one of claims 1 to 7 and a breathable packaging material for containing the deoxidizer composition.

Technical Field

The present invention relates to a deoxidizer composition and a method for producing the same, and more particularly, to an iron-based deoxidizer composition and a method for producing the same.

Background

As a technique for preserving foods, medicines, and the like, a method using a deoxidizer is known. In this method, the article to be stored and the oxygen scavenger are sealed in a gas-tight sealed container, and the oxygen scavenger absorbs oxygen in the sealed container, whereby the atmosphere in the sealed container can be maintained in a substantially oxygen-free state. As a function of the oxygen scavenger, it is required to be small and absorb a large amount of oxygen. In other words, a deoxidizer composition having a high oxygen absorption amount per unit volume is required.

Typical examples of the oxygen scavenger include an iron-based oxygen scavenger containing iron (iron powder) as a main component and a non-iron-based oxygen scavenger containing ascorbic acid, glycerin, or the like as a main component. The oxygen scavenger is appropriately selected depending on the application, but from the viewpoint of oxygen absorption performance, an iron-based oxygen scavenger is widely used.

Iron powder requires moisture in order to absorb oxygen. In a conventional deoxidizer containing iron powder and water, the iron powder and a water retaining agent that retains water supplied thereto are contained in the form of separate powder particles that can be separated from each other. Therefore, a gap is formed between the iron powder and the powder particles of the water retaining agent, and this gap is one of the causes of a decrease in the oxygen absorption amount per unit volume of the oxygen absorbent composition. In addition, the iron powder and the water retaining agent are easily agglomerated and bound to each other to form a lump. When the iron powder is formed into a lump, the surface area of the iron powder that can be oxidized is reduced, and therefore, the oxygen absorption amount is reduced as compared with a case where the iron powder and the water-retaining agent are uniformly dispersed and mixed.

For example, patent document 1 discloses an oxygen absorbent composition containing an oxygen absorbing substance, water and a swelling agent, and being solidified by press molding to eliminate gaps between powder and granules and reduce the volume thereof, thereby achieving compactness. However, the oxygen absorbent composition described in patent document 1 requires a new step of press molding compared to the oxygen absorbent composition that can be produced by merely mixing, and therefore the production cost increases. Further, the iron powder located in the powder and granular material is less likely to be oxidized, and therefore, there is room for improvement in the amount of oxygen absorbed per unit volume.

Patent document 2 aims to solve the problems in the oxygen absorbent composition of patent document 1 and provide an oxygen absorbent composition having an excellent oxygen absorption amount per unit volume, and discloses an oxygen absorbent composition containing a powder having an α layer containing a water retaining agent, a swelling agent, a metal salt and water, a β layer containing iron, and a γ layer containing a porous carrier, wherein the powder forms a layer structure in the order of the α layer, the β layer, and the γ layer from the inside toward the outside of the powder.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2007/046449

Patent document 2: international publication No. 2017/169015

Disclosure of Invention

Problems to be solved by the invention

From the viewpoint of preventing oxidation of the stored article in the sealed container, a deoxidizer is required which absorbs oxygen in the sealed container in as short a time as possible. Further, the oxygen scavenger of patent document 2 needs to be produced through the following steps: a powder or granule as a raw material of the α layer is produced by charging an aqueous solution of a halogenated metal salt while mixing a water retaining agent and a swelling agent, and then iron powder is charged into the powder or granule so that the iron powder is attached to the outside of the α layer to produce an (α layer/β layer) powder or granule.

Accordingly, an object of the present invention is to provide an oxygen absorbent composition having a high oxygen absorption rate in the initial reaction stage of the oxidation reaction of iron. Another object of the present invention is to provide a method for efficiently producing an oxygen absorbent composition having a high oxygen absorption rate in the initial stage of the oxidation reaction of iron.

Means for solving the problems

The present invention relates to the following oxygen scavenger composition and a method for producing the same.

<1> a deoxidizer composition comprising a mixed granulated substance of a composition containing a water-retaining agent, a swelling agent, a metal salt, water and iron.

<2> the oxygen scavenger composition according to <1> above, wherein the average particle diameter is 0.3mm or more and 5.0mm or less.

<3> the oxygen scavenger composition according to <1> or <2>, wherein a layer containing a porous carrier is provided outside the mixed granulated substance.

<4> the oxygen scavenger composition according to any one of <1> to <3>, wherein the water retaining agent contains at least one selected from the group consisting of diatomaceous earth, silica and activated carbon.

<5> the oxygen scavenger composition according to any one of <1> to <4>, wherein the swelling agent contains at least one selected from the group consisting of calcium carboxymethylcellulose, sodium carboxymethylcellulose, calcium bentonite and sodium bentonite.

<6> the oxygen scavenger composition according to any one of <1> to <5>, wherein the mixed granules are not a press molded product.

<7> the oxygen scavenger composition according to any one of <1> to <6>, wherein iron is dispersed throughout the mixed granules.

<8> a method for producing the oxygen scavenger composition according to any one of <1> to <7>, which comprises a step of mixing together a water retaining agent, a swelling agent, a metal salt, water and iron and granulating the mixture.

<9> an oxygen absorbent package comprising the oxygen absorbent composition according to any one of <1> to <7> and a breathable packaging material containing the oxygen absorbent composition.

ADVANTAGEOUS EFFECTS OF INVENTION

In the oxygen absorbent composition of the present invention, the oxygen absorption rate at the initial stage of the oxidation reaction of iron is high, and oxygen in a closed container can be absorbed in a short time. Further, according to the production method of the present invention, it is possible to efficiently produce an oxygen absorbent composition which has a high oxygen absorption rate in the initial stage of the oxidation reaction of iron and absorbs oxygen in a closed container in a short time.

Detailed Description

An embodiment of the present invention will be described below. The present invention is not limited to the embodiments described below.

In the present specification, the term "a to B" in the numerical description means "a to B inclusive" (in the case of a < B) or "a to B inclusive" (in the case of a > B). In the present invention, a combination of preferred embodiments is a more preferred embodiment.

[ deoxidant composition ]

The oxygen absorbent composition of the present invention comprises a mixed granulated substance of a composition containing a water retaining agent, a swelling agent, a metal salt, water and iron. The mixed granules in the present invention are preferably iron dispersed throughout the mixed granules. The oxygen scavenger composition of the present invention may contain only the mixed granulated substance, or may have a layer containing a porous carrier on the outer side of the mixed granulated substance.

The present inventors have found that an oxygen absorbent composition comprising a mixed granulated product of a composition containing a water-retaining agent, a swelling agent, a metal salt, water and iron, which is obtained by mixing and granulating the water-retaining agent, the swelling agent, the metal salt, the water and the iron together, has a high oxygen absorption rate in the initial reaction stage of the oxidation reaction of iron, and can absorb oxygen in a closed container in a short time.

In patent document 2, a powder or granule as a raw material of the α layer is produced by charging an aqueous solution of a halogenated metal salt while mixing a water retaining agent and a swelling agent, then an iron powder is charged into the powder or granule to adhere the iron powder to the outside of the α layer, thereby producing an (α layer/β layer) powder or granule, and further a hydrophobic silica is charged into the (α layer/β layer) powder or granule to adhere the hydrophobic silica to the outside of the β layer, thereby producing an (α layer/β layer/γ layer) powder or granule. The oxygen absorbent composition described in patent document 2 has a practically sufficient oxygen absorption rate in the initial stage of the reaction, but the oxygen absorption rate in the initial stage of the reaction of the oxygen absorbent composition of the present invention is further increased, and oxygen in the sealed container can be absorbed in a further short time.

The detailed mechanism for obtaining the effect of the present invention is not clear, but is presumed as follows: since the water-retaining agent, the swelling agent, the metal salt, water and iron are mixed together and granulated, iron is dispersed throughout the granulated substance, and iron and water are present in the vicinity of each other, the reaction amount in the initial reaction stage of the oxidation reaction of iron is large, and as a result, the oxygen absorption rate in the initial reaction stage is high, and oxygen in the closed container can be absorbed in a short time.

(Water-retaining agent)

The water-retaining agent contained in the oxygen scavenger composition of the present invention is a substance capable of retaining water without permeating water into the inside thereof.

The water retaining agent is not particularly limited as long as it can retain water, and a porous material or a super absorbent resin which can be obtained in general can be used. Examples of the porous material include diatomaceous earth, zeolite, sepiolite, cristobalite, porous glass, silica, activated clay, acid clay, activated carbon, vermiculite, and wood flour. Examples of the super absorbent resin include a polyacrylate resin, a polysulfone resin, a polyacrylamide resin, a polyvinyl alcohol resin, a starch resin, a cellulose resin, and a alginic acid resin. The water retaining agent preferably contains at least one selected from the group consisting of diatomaceous earth, silica and activated carbon. The water retaining agent can be used alone in 1, or according to the need of more than 2 combination. Further, these water-retaining agents can be easily obtained as commercially available products.

Among the above water-retaining agents, activated carbon has a function of promoting an oxidation reaction of iron in addition to a water-retaining function, and is therefore particularly preferred. The type of the activated carbon is not particularly limited, and may be any of wood, coconut shell, coal, and the like.

The properties of the water retaining agent are not particularly limited, and a powder-like water retaining agent having high fluidity is suitably used from the viewpoint of handling property in the production of the oxygen scavenger, and a water retaining agent having a shape close to a sphere is more preferable. The average particle diameter of the water retaining agent is preferably 10 μm or more and 1000 μm or less, more preferably 100 μm or more and 500 μm or less, from the viewpoint of handling property in the production of the oxygen scavenger. The particles of the water retaining agent having the above-mentioned particle size range can be used regardless of the difference between the primary particles, agglomerated particles and granulated materials. The water retaining agent having the particle size within the above range may be used singly or by mixing a plurality of kinds having different particle sizes in an arbitrary ratio.

The content of the water retaining agent in the oxygen absorbent composition is not particularly limited, but is preferably 10 mass% or more and 40 mass% or less, and more preferably 15 mass% or more and 30 mass% or less, in 100 mass% of the oxygen absorbent composition. Further, it is preferably 20 parts by mass or more and 300 parts by mass or less, more preferably 50 parts by mass or more and 200 parts by mass or less, with respect to 100 parts by mass of water. If the content of the water retaining agent is within this range, the oxygen absorbent composition can sufficiently retain water and the oxygen absorption amount per unit volume of the oxygen absorbent composition can be increased.

(swelling agent)

The swelling agent contained in the oxygen absorbent composition of the present invention swells with moisture and has a binding function for retaining the shape of the granulated product. The swelling agent is preferably used in a substantially dry state or in a semi-swollen or swollen state in which a small or necessary amount of water is absorbed.

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

Examples of the inorganic swelling agent include clay minerals such as sodium bentonite, calcium bentonite, and sodium montmorillonite. Examples of the organic swelling agent include organic bentonite; defatted frozen bean curd, agar, starch, dextrin, acacia, gelatin, casein, etc.; semi-synthetic products such as crystalline cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, hydroxyethyl cellulose, lignosulfonic acid, hydroxyethylated starch, etc.; water-insoluble synthetic products such as polyvinyl alcohol and polyvinyl methyl ether. The swelling agent can be used alone in 1 kind, or according to the need of 2 or more kinds in combination. In addition, commercially available products of these swelling agents can be easily obtained.

The clay mineral is preferable because it is inexpensive and also excellent in performance. Clay minerals are also known as inorganic soaps and function as lubricants. It is also known that clay minerals swollen with water exhibit high thixotropy and also exhibit cohesiveness, and therefore, such clay minerals are preferable. Further, a cellulose-based semi-synthetic product is preferable because it exhibits excellent swelling properties. Among them, bentonite such as calcium bentonite and sodium bentonite, carboxymethyl cellulose, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, and the like are preferable because of low cost and high binding power. The swelling agent preferably contains at least one selected from the group consisting of carboxymethylcellulose calcium, carboxymethylcellulose sodium, calcium bentonite, and sodium bentonite.

The average particle diameter of the swelling agent is preferably 0.001 μm or more and 10 μm or less, more preferably 0.01 μm or more and 1.0 μm or less, from the viewpoint of suppressing the generation of dust and from the viewpoint of a binding function.

The content of the swelling agent in the oxygen absorbent composition is not particularly limited, but is preferably 0.1 mass% or more and 20 mass% or less, more preferably 1 mass% or more and 15 mass% or less, in 100 mass% of the oxygen absorbent composition. Further, it is preferably 1 part by mass or more and 15 parts by mass or less, more preferably 3 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of iron. When the content of the swelling agent is within this range, the shape of the oxygen absorbent composition is easily maintained, the ratio of the water retaining agent is not excessively small, the amount of water supplied to iron does not decrease, and the oxygen absorption amount tends to increase further.

(Metal salt)

The metal salt contained in the oxygen absorbent composition of the present invention acts catalytically on the oxidation reaction of iron to improve the activity of iron. The metal salt also serves to prevent water contained in the oxygen absorbent composition from evaporating and being lost by the oxygen absorbent composition.

The metal salt is not particularly limited, but is preferably a metal halide. As the metal halide, those generally known can be used without particular limitation.

The metal in the metal halide 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 them, at least one selected from the group consisting of lithium, potassium, sodium, magnesium, calcium, barium and iron is more preferable. The halide in the metal halide is not particularly limited, and examples thereof include chloride, bromide, and iodide.

The metal halide is preferably calcium chloride, sodium chloride, calcium bromide, sodium bromide, calcium iodide, or sodium iodide, and more preferably calcium chloride or sodium chloride, from the viewpoint of handling property, safety, or the like.

The metal salt may be used alone in 1 kind, or may be used in combination of 2 or more kinds as required. In addition, these metal salts can be easily obtained as commercially available products.

The concentration of the metal salt when the metal salt is formed as a raw material in the form of an aqueous solution is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 20% by mass or less. When the salt concentration is 5 mass% or more, the effect of suppressing the oxidation of the catalytic iron is reduced, and when the salt concentration is 30 mass% or less, the vapor pressure of the moisture can be suppressed from decreasing. It is possible to suppress a decrease in the amount of oxygen absorbed due to insufficient supply of water to the iron.

The content of the metal salt in the oxygen scavenger composition is not particularly limited, but is preferably 0.5 mass% or more and 15 mass% or less, more preferably 1 mass% or more and 10 mass% or less, in 100 mass% of the oxygen scavenger composition. Further, it is preferably 0.5 parts by mass or more and 20 parts by mass or less, more preferably 2 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of iron.

(Water)

The oxygen absorbent composition of the present invention contains water from the viewpoint that the iron-based oxygen absorbent exhibits oxygen absorbing performance. The content of water in the oxygen absorbent composition is not particularly limited, but is preferably 10 mass% or more and 40 mass% or less, and more preferably 15 mass% or more and 30 mass% or less, in 100 mass% of the oxygen absorbent composition. From the viewpoint of oxygen absorption performance, the amount is preferably 20 parts by mass or more and 50 parts by mass or less, and more preferably 25 parts by mass or more and 40 parts by mass or less, based on 100 parts by mass of iron.

(iron)

The shape of iron contained in the oxygen absorbent composition of the present invention is not particularly limited, but from the viewpoint of oxygen absorption performance, availability, and handling easiness, iron powder is preferred. The iron powder is not particularly limited as long as the surface of iron is exposed, and reduced iron powder, electrolytic iron powder, sprayed iron powder, and the like can be suitably used. Further, a ground product or a cut product of cast iron or the like may be used.

The iron powder may be used alone in 1 kind, or 2 or more kinds may be used in combination as necessary. Further, commercially available products of these iron powders can be easily obtained.

In addition, iron powder whose surface is covered with metal halide may be used. The iron powder covered with the metal halide can be produced by mixing an iron powder with an aqueous solution of a metal halide and then drying the mixture to remove moisture. The metal halide coated on the iron powder may cover the aforementioned metal salt.

The average particle size of the iron powder is preferably 1mm or less, more preferably 500 μm or less, and further preferably 200 μm or less from the viewpoint of good contact with oxygen, and is preferably 1 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more from the viewpoint of suppressing the generation of dust. The particle size referred to herein means that the particle size is measured using a particle size according to ISO 3310-1: 2000 (corresponding to JIS Z8801-1: 2006), particle size determined from the weight fraction based on the size of the mesh openings after shaking for 5 minutes.

The specific surface area of the iron powder is preferably 0.05m from the viewpoint of oxygen absorption capacity²A value of at least g, more preferably 0.1m²More than g. The specific surface area of the iron powder can be measured by the BET multipoint method.

The oxygen scavenger composition of the present invention contains iron as a main agent. The content of iron in the oxygen scavenger composition is preferably 40 mass% or more and 90 mass% or less, more preferably 45 mass% or more and 80 mass% or less, further preferably 50 mass% or more and 70 mass% or less, and further preferably 50 mass% or more and 60 mass% or less, with respect to the oxygen scavenger composition.

< Mixed granules >

The oxygen absorbent composition of the present invention comprises a mixed granulated substance of a composition containing a water retaining agent, a swelling agent, a metal salt, water and iron. In the present invention, "granulation" refers to an operation of mixing a raw material powder containing a single component or a plurality of components using a binder or the like, reducing the existence ratio of fine powder compared with the state of the raw material powder, and processing the mixture into granules larger than the raw material powder. The "granulated material" refers to a granular material obtained by the granulation operation, in which the existence ratio of the fine powder is reduced as compared with the state of the raw material powder, and which is processed into a larger grain than the raw material powder. The mixed granules in the present invention are not press molded products. That is, the granulated substance contained in the oxygen absorbent composition of the present invention can be produced simply and at low cost only by mixing without press molding.

In the present invention, the mixed granules are preferably dispersed with iron throughout the whole of the mixed granules. In patent document 2, since a powder or granule as a raw material of the α layer is produced by pouring an aqueous solution of a halogenated metal salt while mixing a water retaining agent and a swelling agent, and then an iron powder is poured into the powder or granule so that the iron powder is attached to the outside of the α layer, a (α layer/β layer) powder or granule is produced, the iron powder is locally present in the vicinity of the outside of the powder or granule. In contrast, as described later, the method for producing the oxygen absorbent composition of the present invention is a method including a step of mixing the water-retaining agent, the swelling agent, the metal salt, water and iron together to granulate, and the iron is dispersed in the whole granulated material in the granulated material obtained by the method.

The content of the mixed granules in the oxygen scavenger composition of the present invention is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and further preferably substantially 100% by mass.

(porous carrier)

The oxygen scavenger composition of the present invention may contain only the mixed granulated substance, or may have a layer containing a porous carrier on the outer side of the mixed granulated substance.

The porous carrier that can be used in the present invention is not particularly limited as long as it has a porous shape. Here, the porous fingerThe surface and the inside of the sample had many pores that could be confirmed by an electron microscope. The porous carrier may be a porous material used for the water retaining agent, but is preferably silica. The silicon dioxide refers to silicon dioxide (SiO)₂) A porous material as a main component. By using silica, the bulk density of the resulting powder increases, and the oxygen absorption amount increases.

The silica is not particularly limited, and examples thereof include hydrophobic silica (surface-treated silica), wet silica, dry silica, silica gel, diatomaceous earth, acid clay, activated clay, pearlite, kaolin, talc, and bentonite. The porous carrier can be used alone in 1 or according to the need of 2 or more combinations to use. These porous carriers are also readily available as commercially available products.

When the oxygen scavenger composition of the present invention comprises a layer containing a porous carrier, the content of the porous carrier in the layer containing a porous carrier is preferably 30% by mass or more, more preferably 50% by mass or more, and still more preferably 80% by mass or more.

When the oxygen absorbent composition of the present invention has a layer containing a porous carrier, the content of the porous carrier in the oxygen absorbent composition is preferably 0.1 mass% or more and 5 mass% or less, and more preferably 0.5 mass% or more and 3 mass% or less. When the content of the porous carrier is in such a range, the bulk density of the oxygen absorbent composition tends to increase, and the oxygen absorption amount tends to further increase, and the flowability of the oxygen absorbent composition improves, whereby the handleability of the oxygen absorbent package during production thereof can be improved.

< shape of deoxidant composition >

The shape of the oxygen absorbent composition of the present invention is not particularly limited, and examples thereof include a spherical shape, an elliptical shape, and a cylindrical shape, and a spherical shape is preferable from the viewpoint that the filling property is more excellent and the bulk density tends to be further increased.

The average particle diameter of the oxygen absorbent composition of the present invention is preferably 0.3mm or more and 5.0mm or less, more preferably 0.5mm or more and 2.0mm or less. When the average particle diameter is 0.3mm or more, adhesion to the contact portion of the powder and granular material of the packaging machine due to static electricity or the like is suppressed at the time of filling and packaging, and when the average particle diameter is 5.0mm or less, the gap between the powder and granular material tends to be too large and the amount of oxygen absorbed per unit volume tends to be reduced. In order to obtain the oxygen absorbent composition having an average particle diameter within the above range, for example, the oxygen absorbent composition may be sieved using a sieve having an aperture of 0.3mm or 2 mm. The average particle diameter can be measured, for example, by a commercially available laser diffraction/scattering particle size distribution measuring apparatus ("LA-960" manufactured by horiba, Ltd.).

The bulk density of the oxygen scavenger composition of the present invention is not particularly limited, but is preferably 1.0g/mL or more, more preferably 1.3g/mL or more, and still more preferably 1.5g/mL or more. When the bulk density is 1.0g/mL or more, the oxygen absorption amount per unit volume tends to be more excellent. In order to obtain the oxygen absorbent composition having a bulk density within the above range, for example, an oxygen absorbent composition having a target bulk density is selected by a specific gravity classifier ("HIGH SPEED ASPIRATOR", manufactured by Tokyo Mill, Ltd.). The bulk density can be measured according to JIS Z8901.

[ method for producing deoxidizer composition ]

The method for producing the oxygen absorbent composition of the present invention is not particularly limited, but a method including a step of mixing together the water-retaining agent, the swelling agent, the metal salt, water and iron and granulating (the production method of the present invention) is preferable. According to the production method of the present invention, the water-retaining agent, the swelling agent, the metal salt, water and iron are mixed to be uniformly dispersed to produce the mixed granules, whereby the oxygen absorbent composition can be efficiently produced. In patent document 2, a powder or granule as a raw material of the α layer is produced by charging an aqueous solution of a halogenated metal salt while mixing a water retaining agent and a swelling agent, then an iron powder is charged into the powder or granule to adhere the iron powder to the outside of the α layer, thereby producing an (α layer/β layer) powder or granule, and further a hydrophobic silica is charged into the (α layer/β layer) powder or granule to adhere the hydrophobic silica to the outside of the β layer, thereby producing an (α layer/β layer/γ layer) powder or granule. That is, a two-stage process of manufacturing a powder and granular material as a raw material of the α layer and then attaching iron powder to the outside of the α layer is required. In contrast, in the production method of the present invention, the deoxidizer composition can be produced by a one-stage step of mixing the water retaining agent, the swelling agent, the metal salt, water, and iron together and granulating, and therefore, the deoxidizer composition can be produced more efficiently than the method of patent document 2. Further, the mixed granules contained in the oxygen absorbent composition of the present invention can be produced simply and at low cost by merely mixing them without press molding.

The mixing device is not particularly limited, and specific examples thereof include a nauta mixer (manufactured by Hosokawa Micron Corporation), a conical mixer (manufactured by yowex chemico), a vertical granulator (manufactured by POWREX corp.), a high-speed mixer (EARTHTECHNICA co., ltd.), and a granulator (akirakko co., ltd.).

In addition, as a method for producing the oxygen absorbent composition having a layer containing a porous carrier, the oxygen absorbent composition may be produced by charging and mixing surface-treated silica (hydrophobic silica) into the mixed granulated product and forming a layer containing a porous carrier on the outer side of the mixed granulated product.

Since iron as a main agent of the deoxidizer reacts with oxygen, the reaction with oxygen proceeds slowly even in the absence of water, metal salts, or the like. Therefore, the mixing is preferably performed in an inert atmosphere (in the case of forming a substantially closed system, the inside of the system is usually set to a reducing atmosphere without oxygen), and heat removal means is appropriately employed.

[ deoxidizer package ]

The oxygen absorbent package of the present invention comprises the oxygen absorbent composition and a breathable packaging material for containing the oxygen absorbent composition.

(packaging Material)

Examples of the wrapping material include a wrapping material formed by laminating 2 sheets of air-permeable wrapping material to form a bag shape; a packaging material formed by laminating 1 piece of air-permeable packaging material and 1 piece of non-air-permeable packaging material to form a bag shape; a packaging material formed by bending 1 sheet of a gas-permeable packaging material and sealing edge portions other than the bent portions to each other to form a bag shape.

Here, when the air-permeable packaging material and the air-impermeable packaging material are square, the packaging material may be a bag-shaped packaging material formed by overlapping 2 sheets of air-permeable packaging material and heat-sealing 4 sides; a packaging material formed by overlapping 1 piece of air-permeable packaging material and 1 piece of non-air-permeable packaging material and heat-sealing 4 edges to form a bag shape; a packaging material obtained by bending 1 sheet of a gas-permeable packaging material and heat-sealing 3 sides except the bent portion to form a bag-like shape. The packaging material may be formed by forming the air-permeable packaging material into a tubular shape, and heat-sealing both end portions and an intermediate portion of the tubular body to form a bag-like shape.

(air-permeable packaging Material)

As the air-permeable packing material, a packing material permeable to oxygen and carbon dioxide is selected. Among these, a breathable packaging material having a resistance to air permeation of 600 seconds or less, more preferably 90 seconds or less, obtained by the grignard method is preferably used. Here, the air permeability resistance means a value measured by the method of JIS P8117 (1998). More specifically, it means the time required for 100mL of air to pass through the air-permeable packaging material by a Grignard air permeability tester (manufactured by Toyo Seiki Seisaku-Sho Ltd.).

As the air-permeable packing material, an air-permeable packing material obtained by imparting air permeability to a plastic film is used in addition to paper and nonwoven fabric. Examples of the plastic film include a film of polyethylene terephthalate, polyamide, polypropylene, polycarbonate, and the like, and a laminate film obtained by laminating and bonding films of polyethylene, ionomer, polybutadiene, ethylene acrylic acid copolymer, ethylene methacrylic acid copolymer, ethylene vinyl acetate copolymer, and the like as a sealant layer. In addition, laminates thereof may also be used as breathable packaging materials.

As a method for imparting air permeability, various methods can be employed in addition to the perforation processing by a cold needle or a hot needle. When the air permeability is provided by the punching process, the air permeability can be freely adjusted by the diameter, number, material, and the like of the punched holes.

The thickness of the laminated film is preferably 50 to 300 μm, and particularly preferably 60 to 250 μm. In this case, a packaging material having excellent heat sealability and suitability for packaging can be formed while maintaining strength as compared with a case where the thickness is outside the above range.

Examples

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 exhibited. In the examples and comparative examples, "part" means part by mass unless otherwise clearly stated.

(average particle diameter of deoxidant composition)

The average particle diameter of the oxygen absorbent composition was measured by a laser diffraction/scattering particle size distribution measuring apparatus ("LA-960" manufactured by horiba, Ltd.).

(bulk Density of deoxidant composition)

The bulk density (unit: g/mL) of the oxygen absorbent composition was measured in accordance with JIS Z8901.

(oxygen absorption amount of deoxidant composition)

A deoxidizer composition (1 g) was added to a gas barrier bag (size 250 mm. times.400 mm) made of a nylon/polyethylene laminated film together with 3000mL of air, and sealed. After the gas barrier bag was kept at 25 ℃ for 4 hours and 72 hours, the oxygen concentration in the gas barrier bag was measured to calculate the oxygen absorption amount (unit: mL). The oxygen absorption amount per unit volume (unit: mL/mL) was calculated by dividing the obtained oxygen absorption amount by the volume (unit: mL) of the oxygen absorbent composition.

Example 1

Diatomaceous earth (iso lite manufacturing "CG-2U" co., ltd. manufactured), 1240 parts of activated carbon (futamar CHEMICAL co., ltd. manufactured "S-W50"), 1120 parts of calcium bentonite (kunmine INDUSTRIES co., ltd. manufactured "neokungubond"), 225 parts of sodium carboxymethylcellulose (NIPPON PAPER CHEMICALs co., ltd. manufactured "F350 HC-4"), 20 parts of sodium chloride aqueous solution obtained by dissolving 407 parts of sodium chloride in 2008 parts of water, and 6000 parts of iron powder (average particle diameter 100 μm) were put into a high-speed mixer (EARTHTECHNICA co., ltd. manufactured "SPG 20L") and mixed at 240rpm for 3 minutes, thereby obtaining a mixed particulate matter.

Further, 110 parts of surface-treated Silica ("SS-30P" manufactured by Tosoh Silica corporation) was charged and mixed at 240rpm for 30 seconds to obtain an oxygen absorbent composition having a porous support layer formed on the outer side of the mixed granules. The average particle diameter of the obtained oxygen absorbent composition was 0.9 mm.

Example 2

In example 1, the mixed granules before the surface-treated silica was charged were collected and used as the oxygen absorbent composition of example 2.

Comparative example 1

Diatomaceous earth (CG-2U manufactured by ltd.) 1240 parts, activated carbon (futamar CHEMICAL co, manufactured by ltd. "S-W50") 1120 parts, calcium bentonite (kunmine INDUSTRIES co, manufactured by ltd. "nookungubnd") 225 parts, and sodium carboxymethylcellulose (NIPPON PAPER CHEMICALs co, manufactured by ltd. "F350 HC-4") 20 parts were put into a high-speed mixer (EARTHTECHNICA co, manufactured by ltd. "SPG 20L") and mixed at 240rpm for 30 seconds, and then a sodium chloride aqueous solution prepared by dissolving sodium chloride 407 parts in water 2008 parts was put into the mixer at 30 seconds while mixing at 240rpm, and further mixed for 60 seconds, thereby obtaining a powder as a raw material for an α layer.

Next, 6000 parts of iron powder (average particle diameter 100 μm) were charged and mixed at 240rpm for 3 minutes to obtain a powder/granule (α layer/β layer) in which a β layer was formed on the outer side of the powder/granule as a raw material of the α layer.

Further, 110 parts of surface-treated Silica ("SS-30P" manufactured by Tosoh Silica corporation) was charged and mixed at 240rpm for 30 seconds to obtain an oxygen absorbent composition containing a powder/particle (α layer/β layer/γ layer) in which a γ layer was formed on the outer side of the powder/particle (α layer/β layer). The average particle diameter of the obtained oxygen absorbent composition was 0.9 mm.

As a result of taking a photograph of a cross section of the obtained oxygen scavenger composition cut with a cutter using a digital microscope ("VHX-2000" manufactured by KEYENCE CORPORATION), it was confirmed that the powder/granule (α layer/β layer/γ layer) had a structure having an α layer in the center, a β layer on the outer side, and a γ layer on the outer side.

Comparative example 2

In comparative example 1, the powder and granular material (α layer/β layer) before the surface-treated silica was charged was collected and used as the oxygen absorbent composition of comparative example 2.

The bulk density and the oxygen absorption amount per unit volume of the obtained oxygen scavenger composition are shown in table 1. In table 1, "method of adding raw materials" indicates a method of adding raw materials other than surface-treated silica, "mixing together" indicates mixing raw materials other than surface-treated silica together, "α layer/β layer" indicates mixing raw materials other than surface-treated silica and iron powder to form powder and granular materials as raw materials of the α layer, and then adding iron powder to form the β layer outside the α layer.

[ Table 1]

TABLE 1

As is clear from the comparison between example 1 and comparative example 1 and the comparison between example 2 and comparative example 2, the oxygen absorbing amount after 4 hours was significantly larger and the oxygen absorbing rate in the initial reaction period of the oxidation reaction of the iron powder was higher in the oxygen absorbing compositions of examples 1 and 2 in which the raw materials were mixed together, as compared with the oxygen absorbing compositions of comparative examples 1 and 2 in which the β layer was formed on the outer side of the α layer. That is, the oxygen scavenger compositions of examples 1 and 2 can absorb oxygen in a closed container in a short time.

Further, as is clear from the comparison of example 1 with comparative example 1 and the comparison of example 2 with comparative example 2, according to the method of example in which the raw materials other than the surface-treated silica are mixed together, the oxygen absorbent composition having the bulk density and the oxygen absorption amount per unit volume after 72 hours substantially equal can be efficiently produced in one stage, as compared with the production method of comparative example in which a two-stage process of forming the powder particles as the raw material of the α layer, adding the iron powder, and forming the β layer on the outer side of the α layer is required.