JP2017203089A - Oxygen-absorbing molded body and method for producing the same, oxygen-absorbing multilayer body, and oxygen-absorbing package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen-absorbing molded body having excellent humidity control property while keeping high oxygen absorbing property, even when containing a predetermined amount or more of a metal compound.SOLUTION: An oxygen-absorbing molded body is a molded body containing metal particles containing one or two metal selected from iron and nickel, a thermoplastic resin, and a metal compound having a content of 0.1 mass% or more and 20 mass% or less in terms of an oxide, where an average particle diameter of the metal particles is 5.0 μm or more and 200 μm or less, a BET specific surface area of the metal particles is 10 m/g or more, and water-absorbing ability calculated from expression (1):water-absorbing ability (mass%)=100×(M2-M1)/M1 is 3.0 mass% or less. In expression (1), M1 represents a mass of the molded body, and M2 represents a mass after the molded body is stored at 40°C and 75%H.SELECTED DRAWING: None

Description

  The present invention relates to an oxygen-absorbing molded body and a method for producing the same, an oxygen-absorbing multilayer body, and an oxygen-absorbing package.

  An oxygen absorbent is used as one of preservatives for foods and pharmaceuticals. The oxygen absorbent is used to prevent the object to be stored from being oxidized and deteriorated, but various performances are required depending on the properties of the object.

For example, Patent Document 1 has an object of providing an oxygen-absorbing resin composition having an ability to absorb oxygen in an atmosphere even in an atmosphere having little or no moisture and containing a small amount of moisture. , (I) (A) an alloy containing at least one transition metal selected from the group consisting of iron, cobalt, nickel, and copper, and (B) aluminum is subjected to an alkaline aqueous solution treatment, and a component ( B) a metal obtained by eluting and removing at least part of (B), and obtained by eluting and removing at least part of component (B) by BET method An oxygen-absorbing resin composition comprising an oxygen absorbent having a specific surface area of at least 10 m ² / g and (II) a thermoplastic resin and having a water content of 5000 ppm or less is disclosed.

Japanese Patent Laying-Open No. 2015-7148

  The metal described in Patent Document 1 is porous metal particles obtained by partially eluting and removing an alloy containing a metal such as iron or nickel with an acid / alkali. The oxygen-absorbing resin composition containing porous metal particles can obtain high oxygen absorbability without requiring moisture. On the other hand, the oxygen-absorbing resin composition containing porous metal particles often contains a predetermined amount of moisture due to the retention of moisture in the surface and structure of the porous metal particles. . In particular, it is relatively difficult to completely remove the moisture retained in the porous metal particle structure. Patent Document 1 also describes that the oxygen-absorbing resin composition is heated so that the water content in the oxygen-absorbing resin composition is 5000 ppm or less, but it is still possible to completely remove the water. Have difficulty.

  However, when an oxygen-absorbing resin composition containing porous metal particles is molded, by applying the pressure and temperature necessary to mold the resin, a small amount of retained moisture is released and foamed. Thus, an oxygen-absorbing molded article having excellent moldability at a high level cannot be obtained.

  Here, in order to suppress the foaming described above, the oxygen-absorbing resin composition may further contain a desiccant such as a metal compound. Thereby, it is possible to obtain an oxygen-absorbing molded article having excellent moldability due to the water released from the porous metal particles during molding being absorbed by the desiccant. However, the desiccant remains in the oxygen-absorbing molded body even after being molded, and this oxygen-absorbing molded body cannot be used when storing an object that is not desired to be dried. Moreover, it is difficult to remove only the desiccant after molding.

  Then, even if it is a case where a predetermined amount or more of metal compounds are included, this invention aims at providing the oxygen absorption molded object which has the outstanding humidity control property, maintaining high oxygen absorptivity.

  As a result of researches to solve the above-mentioned problems of the prior art, the present inventors include metal particles containing iron and / or nickel, a thermoplastic resin, and a metal compound whose content is within a predetermined range. The oxygen-absorbing molded article having an average particle diameter and a BET specific surface area of the metal particles within a predetermined range and having an absorption capacity equal to or greater than a predetermined value has excellent humidity control while maintaining high oxygen absorption. The headline, the present invention has been reached. That is, the present invention is as follows.

[1]
Metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a metal compound whose content is 0.1% by mass or more and 20% by mass or less in terms of oxides, A molded body,
The average particle diameter of the metal particles is 5.0 μm or more and 200 μm or less, and the BET specific surface area of the metal particles is 10 m ² / g or more,
The water absorption capacity calculated from the following formula (1) is 3.0% by mass or less.
Oxygen absorption molding.
Water absorption capacity (mass%) = 100 × (M2-M1) / M1 (1)
(In the formula, M1 represents the mass of the molded body, and M2 represents the mass after storing the molded body under the conditions of 40 ° C. and 75% RH.)
[2]
The metal compound is a metal oxide and a metal hydroxide,
Calculated from the following formula (2), the molar ratio of the metal hydroxide to the metal oxide is 0.5 or more.
The oxygen-absorbing molded article according to [1].
Molar ratio = [(B1 × M3 / M1) −A] / A (2)
(In the formula, A represents the water absorption capacity, B1 represents the theoretical water absorption capacity of the metal compound, M1 represents the mass of the molded body, and M3 represents the mass of the metal compound.)
[3]
Molding metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a metal compound having a content of 0.1% by mass or more and 20% by mass or less in terms of oxide. A molding step for obtaining a molded body;
A humidity control step of bringing 1.0 mL / m ² or more and 40 mL / m ² or less of water vapor into contact with water or applying water to the molded body in terms of liquid water,
A method for producing an oxygen-absorbing molded article.
[4]
Metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a metal compound whose content is 0.1% by mass or more and 20% by mass or less in terms of oxides, An oxygen absorbing layer;
On one side of the oxygen absorbing layer, one or more thermoplastic resins having a water vapor permeability of 25 μm thickness of 100 g / m ² or less at a temperature of 40 ° C. and a humidity of 90% RH are contained. A sealant layer to
A gas barrier layer is provided on the other surface side of the oxygen absorption layer,
The average particle diameter of the metal particles is 5.0 μm or more and 200 μm or less, and the BET specific surface area of the metal particles is 10 g / m ² / day or more,
Oxygen absorbing laminate.
[5]
The sealant layer contains a cyclic polyolefin;
The oxygen absorbing laminate according to [4].
[6]
A packaging container including at least a part of the oxygen-absorbing laminate according to [4] or [5],
The oxygen-absorbing laminate includes an oxygen-absorbing layer in the packaging container, a sealant layer inside the oxygen-absorbing layer, and a gas barrier layer outside the oxygen-absorbing layer.
Oxygen absorbing packaging container.

  According to the oxygen-absorbing molded article according to the present invention, even when a predetermined amount or more of the metal compound is included, the oxygen-absorbing molded article has excellent humidity control properties while maintaining high oxygen absorption.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified within the scope of the gist.

(Oxygen-absorbing molded product)
The oxygen-absorbing molded body of the present embodiment includes metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a content of 0.1% by mass or more and 20% by mass in terms of oxide. It is a molded object containing the following metal compounds. The average particle diameter of the metal particles is 5.0 μm or more and 200 μm or less, and the BET specific surface area of the metal particles is 10 m ² / g or more. Furthermore, in the oxygen absorption molding of this embodiment, the water absorption capacity calculated from the following formula (1) is 3.0% by mass or less.
Water absorption capacity (mass%) = 100 × (M2-M1) / M1 (1)
In the formula, M1 represents the mass of the molded body, and M2 represents the mass after the molded body is stored under conditions of 40 ° C. and 75% RH. Here, M1 and M2 are measured by the method described in Examples described later.

  Although the oxygen absorption molding of this embodiment is not specifically limited, It can be used with various forms, such as a film form, a sheet form, a pellet form, and a powder form. Among these, a film-like, sheet-like, or powder-like form is preferable because the surface area per unit mass increases and the oxygen absorption rate tends to be further improved. In the case of a film, the thickness is preferably 10 μm or more and less than 250 μm, and in the case of a sheet, the thickness is preferably 250 μm or more and less than 3.0 mm. Moreover, when it is a powder form, the average particle diameter becomes like this. Preferably they are 1.0 micrometer or more and 1000 micrometers or less, More preferably, they are 10 micrometers or more and 500 micrometers or less.

The water absorption capacity of the oxygen-absorbing molded body is calculated from the following formula (1) and is 3.0% by mass or less, preferably 1.5% by mass or less, and more preferably 0.5% by mass or less.
Water absorption capacity of oxygen-absorbing molded article = 100 × (M2-M1) / M1 (1)
In formula (1), M1 represents the mass of the oxygen-absorbing molded body, and M2 represents the mass after storing the oxygen-absorbing molded body at 40 ° C. and 75% RH. Moreover, M2 is specifically measured by the method described in the Example mentioned later.
When the water absorption capacity is 3.0% by mass or less, excellent humidity control is obtained. Moreover, in order to obtain the molded object whose water absorption capability is 3.0 mass% or less, what is necessary is just to manufacture a molded object by performing the humidity control process mentioned later, for example.

[Metal particles]
The metal particle of this embodiment contains 1 type or 2 types of metals selected from iron and nickel. The average particle diameter of the metal particles is 5.0 μm or more and 200 μm or less, and the BET specific surface area of the metal particles is 10 m ² / g or more. Specific examples of such metal particles include porous metal particles. As such porous metal particles, (A) one or two kinds of transition metals selected from iron and nickel (hereinafter also referred to as “component (A)” and “(A)”), (B) An alloy containing one or more selected from the group consisting of amphoteric metals, magnesium and silicon (hereinafter also referred to as “component (B)” or “(B)”), an acid or an alkali And a metal obtained by elution and removal of at least a part of the component (B). Such a metal is also referred to as a Raney metal. Here, “alloy” means not only a single composition having a certain crystal structure, but also a mixture thereof and a mixture of metals themselves.

  The average particle size of the metal particles is 5.0 μm or more and 200 μm or less, and the particle size distribution is more preferable as it is narrower. In order to obtain metal particles having an average particle diameter of 5.0 μm or more and 200 μm or less, a commercially available mesh sieve (for example, a 200 mesh sieve or the like) is used to eliminate particles having a large particle diameter or to align the particle diameter distribution. ) Can be used for appropriate sieving (classification). In the case of the atomizing method, the powder tends to be nearly spherical and the particle size distribution tends to be narrow.

The specific surface area (BET specific surface area) of the metal particles by the BET method is 10 m ² / g, preferably 20 m ² / g, more preferably 40 m ² / g. In order to obtain metal particles having a specific surface area of 10 m ² / g and an average particle diameter of 5.0 μm or more and 200 μm or less, metal particles having a porous shape may be used as described later.

  The transition metal that can be used as the component (A) is not particularly limited as long as it contains at least iron or nickel, but an iron or nickel metal or an alloy of iron and nickel is preferable.

  The component (B) is not particularly limited as long as it is a metal that is subjected to acid or alkali aqueous treatment and at least a part of which is eluted and removed, but is selected from the group consisting of aluminum, zinc, tin, lead, magnesium, and silicon. One type or two or more types are preferable. Among these, at least one selected from aluminum, zinc, magnesium, or silicon is preferable, more preferably at least one of aluminum, zinc, magnesium, or silicon, and still more preferably aluminum. Aluminum is generally inexpensive.

  The alloy containing the component (A) and the component (B) may further contain additional metals such as molybdenum, chromium, titanium, vanadium, and tungsten, and may further contain additional components such as cyanic acids. Also good.

  The alloy containing the component (A) and the component (B) can be prepared by, for example, a melting method. At this time, the composition ratio of the component (A) and the component (B) is preferably 20% by mass or more and 80% by mass or less when the component (A) is 20% by mass or more and 80% by mass or less. %, More preferably, when the component (A) is 30% by mass or more and 70% by mass or less, the component (B) is 30% by mass or more and 70% by mass or less. To give a more specific example, when the component (A) is iron or nickel and the component (B) is aluminum, the proportion of iron or nickel is 30% by mass or more and 55% by mass or less, and the proportion of aluminum Is more preferably 45% by mass or more and 70% by mass or less.

  The obtained alloy may be subjected to an acid or alkali aqueous solution treatment as it is, but is preferably subjected to an acid or alkali aqueous solution treatment after being finely pulverized. In this specification, “alloy” includes not only a single composition having a specific crystal structure but also a mixture thereof and a mixture of metals themselves.

  As a method for finely pulverizing the alloy, a conventional method for crushing and pulverizing metals can be used as appropriate, for example, pulverizing with a jaw crusher, a roll crusher, a hammer mill, etc. It can be finely pulverized with a ball mill. Alternatively, the molten alloy may be pulverized by a rapid solidification method such as an atomizing method. Here, when the atomizing method is used, it is preferably performed in an inert gas such as an argon gas. As the atomizing method, for example, the method described in JP-A-5-23597 can be used.

  Next, the alloy or alloy powder obtained as described above is subjected to an acid or alkali aqueous solution treatment to elute and remove at least part of the component (B) from the alloy. That is, as the oxygen absorbent used in the storage method according to the present embodiment, a metal obtained after eluting and removing at least a part of the component (B) from the alloy is used.

  As the aqueous solution of acid or alkali, the component (A) does not dissolve or hardly dissolves, and the component (B) mainly dissolves, or both the components (A) and (B) dissolve. As long as the dissolution rate of the component (B) is higher than that of the component (A), it can be used without any particular limitation.

Examples of the acid in the aqueous acid solution include hydrochloric acid, sulfuric acid, and nitric acid. Examples of the alkali in the aqueous alkaline solution include sodium hydroxide, potassium hydroxide, calcium hydroxide, and tetramethylammonium hydroxide (TMAH). ), Na ₂ CO ₃ , K ₂ CO ₃ , and ammonia. About these acid and alkali aqueous solution, you may use it in combination of 2 or more type as needed.

  According to a preferred aspect of the present embodiment, an alkaline aqueous solution is preferably used as the acid or alkaline aqueous solution, and a sodium hydroxide aqueous solution is more preferred. For example, when aluminum is used as the component (B), when sodium hydroxide is used as the alkaline aqueous solution, excess sodium hydroxide can be easily removed by washing with water, and the eluted aluminum can be easily removed. The effect of reducing the number of washings can be expected.

  In the acid or alkali aqueous solution treatment, preferably, in the case of an alloy powder, the alloy powder is gradually added to the acid or alkali aqueous solution while stirring, but the alloy powder is put in water and concentrated acid is added here. Alternatively, alkali may be dropped.

  In the acid or alkali aqueous solution treatment, the concentration of the acid or alkali aqueous solution used is preferably 5.0% by mass or more and 60% by mass or less, and more preferably, for example, 10% by mass or more and 40% by mass in the case of sodium hydroxide. It is as follows.

  In the acid or alkali aqueous solution treatment, the temperature of the aqueous solution is preferably about 20 to 120 ° C., for example. A more preferable temperature is 25 to 100 ° C.

  The treatment time for which the alloy or alloy powder is subjected to the acid or alkali aqueous solution treatment may vary depending on the shape and state of the alloy used, the amount thereof, the concentration of the acid or alkali aqueous solution, the temperature at the time of treatment, etc. Preferably it is 30 to 300 minutes. By adjusting the treatment time, the elution amount of the component (B) from the alloy can be adjusted.

  In the present embodiment, at least a part of the component (B) is eluted and removed from the alloy by treatment with an aqueous solution of acid or alkali. Here, “leaving and removing at least a part of the component (B)” means to elute and remove a part of the component (B) from the alloy containing the component (A) and the component (B), It also includes the case where all of component (B) is eluted and removed from the alloy. In addition, in the process of elution of component (B), the possibility that a part of component (A) is dissolved as a result cannot be denied. Therefore, “at least a part of component (B)” includes only component (B). There is no need to interpret it only when it is eluted by an aqueous solution of acid or alkali.

  By treatment with an aqueous solution of acid or alkali, at least a part of component (B) (for example, aluminum), preferably most of it is eluted from the alloy. The elution ratio of the component (B) from the alloy can be indicated by the content (mass basis) (residual rate) of the component (B) in the metal obtained by elution removal.

  In the metal particles used in the present embodiment (that is, the metal after the component (B) is eluted), the content of the component (B) is preferably 0.01% by mass or more and 50% by mass or less, more preferably. Is 0.1 mass% or more and 40 mass% or less. More specifically, for example, when the alloy is an Al—Fe alloy, the content of aluminum in the metal obtained by elution and removal of aluminum by treatment with an aqueous solution of acid or alkali is preferably 0.01% by mass or more and 50%. It is not more than mass%, more preferably not less than 0.1 mass% and not more than 40 mass%, and still more preferably not less than 1.0 mass% and not more than 5.0 mass%. In addition, content of the component (B) (for example, aluminum) in the metal used for an oxygen absorber can be measured by ICP method, for example.

The metal obtained as described above has a porous shape (or a porous body). Here, the porous shape means a state having a large number of pores on the surface and inside that can be confirmed with an electron microscope. The degree of the porous shape of the metal can be expressed by its specific surface area. Specifically, the specific surface area of the metal according to the BET method is at least 10 m ² / g, preferably at least 20 m ² / g, more preferably at least 40 m ² / g.

For example, when iron is used as the component (A) and aluminum is used as the component (B), the specific surface area of the resulting porous metal (by the BET method) is about ^{20 to} 120 m ² / g. In the case of conventional non-porous iron powder (reduced iron powder or atomized iron powder), the specific surface area is about 0.07 to 0.13 m ² / g, and it is clear whether it is a porous shape or not. It is.

Moreover, the degree of the porous shape which a metal has can also be represented by a bulk density. The bulk density of the metal particles used in the oxygen-absorbing molded body of the present embodiment is preferably 2.0 g / cm ³ or less, more preferably 1.5 g / cm ³ or less. Incidentally, in the case of conventional iron powder (reduced iron powder or atomized iron powder) that is not porous, the bulk density is about 2 to ³ g / cm ³ .

  In the present embodiment, the porous metal used as the active metal has a high oxygen absorption activity, and therefore has an atmosphere of a low humidity condition (for example, a condition of 30% RH (relative humidity) (25 ° C.) or lower). Even below, it can be suitably used as an oxygen absorbent. Of course, even in an atmosphere of high humidity conditions (for example, conditions of 100% RH (relative humidity) (25 ° C.)), it can be suitably used as an oxygen absorbent.

  Therefore, the metal obtained as described above contains at least 5.0 mL / g oxygen, more preferably 10 mL / g oxygen in a low humidity atmosphere of 30% RH (relative humidity) (25 ° C.) or less. Can absorb. Moreover, the oxygen absorption amount when the metal particles made of the metal are used alone as an oxygen absorbent is, for example, 5.0 to 150 mL in a low humidity atmosphere of 30% RH (relative humidity) (25 ° C.) or less. / G.

[Thermoplastic resin]
The type of the thermoplastic resin in the present embodiment is not particularly limited, but examples thereof include polyolefin resins, polyester resins, polyamide resins, polyvinyl alcohol resins, and chlorinated resins. Among these, polyethylene, polypropylene, ethylene- Vinyl acetate copolymers, elastomers, and mixtures thereof can be suitably used.

  As the polyolefin resin, a conventionally known polyolefin resin can be used. For example, various polyethylenes (PE) such as high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, ultra low density polyethylene, polyethylene by metallocene catalyst, polystyrene, polymethylpentene, propylene homopolymer, propylene -Polypropylenes, such as an ethylene block copolymer and a propylene-ethylene random copolymer, are mentioned. Polyolefin resin is used individually by 1 type or in combination of 2 or more types.

  Due to oxygen absorption performance and film processability, polyolefin resins include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, various polyethylenes such as polyethylene using a metallocene catalyst, and propylene-ethylene block copolymers. Various polypropylenes such as propylene-ethylene random copolymer are particularly preferably used. These polyolefin resins include ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, if necessary. A polymer, an ethylene-methyl methacrylate copolymer, or a thermoplastic elastomer may be added.

  A conventionally known polyester resin can be used as the polyester resin. For example, aromatic polyester and aliphatic polyester are mentioned, and more specifically, polyethylene terephthalate (PET) is mentioned.

  As the polyamide resin, a conventionally known polyamide resin can be used. Examples thereof include aromatic polyamides and aliphatic polyamides, and more specifically, nylon-6, nylon-6,6, nylon-6,12, and polymetaxylylene adipamide (for example, Mitsubishi Gas Chemical Co., Ltd.). MX nylon).

  A conventionally known polyvinyl alcohol resin can be used as the polyvinyl alcohol resin. Here, the “polyvinyl alcohol resin” means a resin obtained by saponifying a vinyl ester polymer or a copolymer of a vinyl ester and another monomer using an alkali catalyst. The saponification degree of the vinyl ester component of the polyvinyl alcohol resin is preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more. The polyvinyl alcohol resin may be a blend of two or more types of polyvinyl alcohol resins having different degrees of saponification.

  As the ethylene vinyl alcohol copolymer resin (EVOH), a conventionally known ethylene vinyl alcohol copolymer resin can be used. The ethylene-vinyl alcohol copolymer resin means a resin obtained by saponifying an ethylene-vinyl ester copolymer. Among them, an ethylene-vinyl alcohol copolymer having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more is preferable. The lower limit of the ethylene content of the ethylene-vinyl alcohol copolymer resin is preferably 20 mol%, more preferably 25 mol%. The upper limit of the ethylene content is preferably 55 mol%, more preferably 50 mol%. The saponification degree of the vinyl ester component is preferably 85% or more, more preferably 90% or more, and still more preferably 99% or more.

  A conventionally well-known chlorine resin can be used as a chlorine resin. Examples thereof include block copolymers, graft copolymers mainly composed of polyvinyl chloride and polyvinylidene chloride (PVDC), and polymer blends mainly composed of vinyl chloride resin. Examples of comonomers copolymerized with vinyl chloride include vinyl acetate, vinylidene chloride, acrylic acid, methacrylic acid and esters thereof, acrylonitriles, olefins such as ethylene and propylene, maleic acid and anhydrides thereof. it can.

  Among the above thermoplastic resins, in view of oxygen absorption, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, elastomer, and mixtures thereof are preferable.

  In the thermoplastic resin, unless the effects according to the present invention are essentially impaired, a dispersant such as a wax and a surfactant, a color pigment such as titanium oxide; an antioxidant, a slip agent, an antistatic agent, a stabilizer, and the like Additives, calcium carbonate, clay, mica, silica and other fillers; desiccants, deodorants, phenolic antioxidants, phosphorus antioxidants, lactone antioxidants, flame retardants, light stabilizers, UV rays Optional components such as an absorbent, a lubricant, a deodorant, an antistatic agent, an anti-tacking agent, an antifogging agent, and a surface treatment agent can be blended. In particular, a dispersant may be added to improve the dispersion of the oxygen absorbent. Moreover, what is necessary is just to add antioxidant, in order to recycle and reprocess the scrap generated during manufacture. A blending method is not particularly limited, but is generally melt kneaded with a resin.

[Metal compounds]
As the metal compound of the present embodiment, a metal compound that absorbs moisture released from the metal particles is suitably used in order to suppress foaming when forming a molded body. The metal compound is preferably one that chemically adsorbs moisture so that re-release of moisture does not occur. Moreover, what can hold | maintain a solid state after moisture adsorption | suction so that the structure of the oxygen absorption molding before and behind moisture absorption may not be affected is preferable. Examples thereof include alkali metal oxides such as sodium oxide and potassium oxide, and alkaline earth metal oxides such as magnesium oxide, calcium oxide, strontium oxide, and barium oxide.

  The oxygen absorption molded object of this embodiment contains the metal compound whose content is 0.1 mass% or more and 20 mass% or less in conversion of an oxide. Content of a metal compound becomes like this. Preferably it is 0.5 to 15 mass%, More preferably, it is 1.0 to 10 mass%. When the content of the metal compound is 0.1% by mass or more, foaming during molding of the oxygen-absorbing molded body is suppressed. Moreover, when the content of the metal compound is 20% by mass or less, when storing an article using an oxygen-absorbing molded article, the storage environment of the article is conditioned and suitable for an object that does not require drying. A safe storage environment.

The metal compound is composed of a metal oxide and a metal hydroxide. The metal oxide chemically adsorbs moisture and changes to a metal hydroxide. At this time, the number of water molecules that can adsorb one molecule of the metal compound is determined by the molecular species, and the theoretical water absorption capacity of the metal compound is also determined. For example, if the metal oxide is calcium oxide, one molecule of water H ₂ O reacts with one molecule of calcium oxide CaO, thereby generating one molecule of Ca (OH) ₂ . For this reason, the theoretical water absorption capacity of the metal compound is 32.1% by mass.

In the oxygen-absorbing molded body, the metal compound is a metal oxide and a metal hydroxide,
It is preferable that the molar ratio of the metal hydroxide to the metal oxide, calculated from the following formula (2), is 0.5 or more from the viewpoint of reliably achieving the effects of the present invention.
Molar ratio = [(B1 × M3 / M1) −A] / A (2)
In formula (2), A represents the water absorption capacity obtained from the above-described formula (1), B1 represents the theoretical water absorption capacity of the metal compound, M1 represents the mass of the molded body, and M3 represents the metal compound. The mass of Here, the mass of the metal compound can be calculated, for example, from the content of the metal compound measured using the ICP method.

When a metal compound absorbs water, the metal oxide changes to a metal hydroxide. From this, the molar amount of the metal oxide can be obtained from the following formula.
Molar amount of metal oxide = water absorption capacity (above A1) / theoretical water absorption capacity (above B1) × amount of metal compound The molar amount of the metal hydroxide can be obtained from the following formula.
Mole amount of metal hydroxide = (theoretical water absorption capacity (above B1) −water absorption capacity (above A1)) / theoretical water absorption capacity (above B1) × the amount of the metal compound The molar ratio can be calculated from the above formula (2).

  The oxygen-absorbing molded body of the present embodiment can be applied from a region having a high water activity to a region having a low water activity. Thereby, it can apply suitably to the articles | goods with which water activity is low and the preservation | save on the dry conditions of low humidity is required. Moreover, since the oxygen absorption molded object of this embodiment suppresses that the preservation | save object of an article | item becomes a dry state, it can be applied suitably also to the article | item which does not desire drying. The water activity is a scale indicating the free water content in an article, and is indicated by a number from 0 to 1, with 0 for an article without moisture and 1 for pure water. That is, the water activity Aw of an article is P, the water vapor pressure in the space after the article is sealed and reaches equilibrium, the water vapor pressure in pure water is P0, the relative humidity in the space is RH (%), Is defined as Aw = P / P0 = RH / 100.

  In order to store an object that does not require drying, the relative humidity (RH) of the storage atmosphere is preferably 10% RH or more and 90% RH or less, more preferably 20% RH or more and 80% RH or less, and further preferably Is 30% RH or more and 70% RH or less.

  The target for which the oxygen-absorbing molded article of this embodiment is suitably used is not particularly limited, and examples thereof include pharmaceuticals such as pharmaceutical solid tablets, patches, injections, and infusions, and foods rich in water. When stored in a dry state, the solid preparation is unfavorable because the tablet disintegrates and the contained components are altered in patches, injections, infusions, and the like. In addition, it is not preferable to store a food containing a lot of moisture in a dry state because it leads to a decrease in flavor.

[Method for producing oxygen-absorbing molded article]
The method for producing an oxygen-absorbing molded body of the present embodiment includes a metal particle containing one or two metals selected from iron and nickel, a thermoplastic resin, and a content of 0.1% by mass or more in terms of oxide. A molding step of molding a metal compound of 20% by mass or less to obtain a molded body is provided. Further, this production method, the obtained molded article, a humidifying process for applying or water contacting the 1.0 mL / m ² or more 40 mL / m ² or less of water vapor in the water in terms of liquid, further comprising be able to.

[Molding process]
Specifically, the molding step can be performed by mixing metal particles, a thermoplastic resin, and a metal compound. At this time, the content of the metal particles of the oxygen-absorbing molded body is preferably 1.0% by mass to 80% by mass, more preferably 5.0% by mass to 70% by mass, and further preferably 10% by mass. It is added so that it becomes 65 mass% or less. When the content of the metal particles is in the above range, the content of the metal particles is 1.0% by mass or more, so that there is an advantage that higher oxygen absorption performance can be obtained, and the content of the metal particles is 80%. When the content is less than or equal to mass%, it is possible to suppress an increase in the overall viscosity accompanying an increase in the metal content, so that the resin processability and the like can be favorably maintained.

  As an example of producing an oxygen-absorbing molded body according to the present embodiment, for example, a master batch containing metal particles and a thermoplastic resin is melt-kneaded, and this is molded into a desired shape as necessary, and then cooled. It can be set as the oxygen absorption molding of embodiment.

  The method for forming the oxygen-absorbing molded body of the present embodiment into a desired shape is not particularly limited, and a conventionally known method can be employed. In the case of a sheet or a film, it can be formed by, for example, forming by a solution casting method, or by extrusion through a die having a predetermined shape such as a T-die or a circular die using a single-screw or multi-screw melt extruder. Of course, a compression molding method, an injection molding method, or the like can be employed.

[Humidity control process]
In this embodiment, in order to suppress that the target object preserve | saved with an oxygen absorption molded object is dried excessively, you may further have a humidity control process in the manufacturing process of an oxygen absorption molded object. It is preferable to perform the humidity control step after the molding step of the oxygen absorbing molded body so as not to affect the foaming suppression effect at the time of molding the oxygen absorbing molded body with the metal compound. By including a humidity control step in the manufacturing process of the oxygen-absorbing molded body, the water absorption capacity of the oxygen-absorbing molded body can be reduced, and an object that does not require drying can be suitably stored.

In the present embodiment, a conventionally known method can be used for the humidity control step that is suitably used, and is not particularly limited. For example, a method in which water vapor is brought into direct contact with the oxygen-absorbing molded body, and a method in which liquid water is applied using a water-containing rubber or resin or a metal roll can be used. The water vapor or water supplied to the oxygen-absorbing molded body in the humidity control step is preferably 1.0 mL / m ² or more and 40 mL / m ² or less in terms of liquid water. More preferably 3.0 mL / m ² or more 35 mL / m ² or less, more preferably 5.0 mL / m ² or more 30 mL / m ² or less. When there is too little water to supply, the water absorption capability of an oxygen absorptive form cannot fully be reduced. On the other hand, when there is too much water to supply, water will adhere to the surface of an oxygen absorptive form, and there exists a concern about generation | occurrence | production and proliferation of fungi.

[Oxygen absorbing laminate]
The oxygen-absorbing laminate of this embodiment is a laminate comprising an oxygen-absorbing layer, a sealant layer containing one or more thermoplastic resins on one side, and a gas barrier layer on the other side. . Hereinafter, details of each layer and its components of the oxygen-absorbing laminate of the present embodiment will be described.

[Oxygen absorbing layer]
The oxygen absorption layer is composed of metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a metal compound having a content of 0.1% by mass or more and 20% by mass or less in terms of oxide. It is a layer containing.

[Sealant layer]
A sealant layer is a layer containing 1 type, or 2 or more types of thermoplastic resins. As the thermoplastic resin, the same type as that described in “Thermoplastic resin” in the above oxygen-absorbing laminate can be used. However, the use of a thermoplastic resin having a low water vapor permeability is more conservative. It is preferable because moisture transfer from the object to the metal compound can be prevented. The water vapor permeability of the thermoplastic resin used for the sealant layer is preferably 100 g / m ² / day or less, more preferably 70 g in terms of 25 μm thickness at a temperature of 40 ° C. and a humidity of 90% RH. / M ² / day or less, more preferably 50 g / m ² / day or less.

  The sealant layer of this embodiment may contain a cyclic polyolefin resin for the purpose of lowering the water vapor permeability. A conventionally known cyclic polyolefin resin can be used as the cyclic polyolefin resin. Examples of the cyclic polyolefin resin include a cycloolefin polymer (COP) synthesized by ring-opening polymerization and hydrogenation of norbornenes and a cycloolefin copolymer (COC) which is an addition polymer of norbornenes and ethylene.

[Gas barrier layer]
The gas barrier layer is a layer capable of suppressing gas permeation. The gas barrier layer may be made of a barrier resin using polymetaxylylene adipamide resin, ethylene-vinyl alcohol copolymer resin, polyvinylidene chloride, amine-epoxy curing agent, etc. It may be made of a deposited film of a product or a metal foil.

[Oxygen absorbing packaging container]
According to another aspect of this embodiment, the oxygen-absorbing laminate of this embodiment is provided with a packaging container that includes at least a portion thereof, and the oxygen-absorbing laminate includes an oxygen-absorbing layer in the packaging container, and oxygen-absorbing. An oxygen-absorbing packaging container is provided that includes a sealant layer inside the layer and a gas barrier layer outside the oxygen-absorbing layer.

  More specifically, as the form of the oxygen-absorbing molded body of the present embodiment, for example, all of various packaging forms such as a pouch, a container lid, a tray, a cup, a laminated tube container, a paper container, a bottle, or a blister container Or it can be used as a part. According to still another preferred aspect of the present embodiment, the oxygen-absorbing resin composition of the present embodiment includes a pouch, a container lid, a tray, a cup, a laminated tube container, a paper container, a bottle, a deep-drawn container, and a vacuum. Used as all or part of various packaging forms such as molded containers or blister containers.

  Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples. However, the present embodiment is not construed as being limited to the contents of the following examples.

(Preparation of dried Al-Fe porous metal powder)
Al (aluminum) powder and Fe (iron) powder were mixed at a ratio of 50% by mass and dissolved in nitrogen to obtain an Al-Fe alloy. The obtained Al—Fe alloy was pulverized using a jaw crusher, a roll crusher, and a ball mill, and the pulverized product was classified using a net having a mesh size of 250 mesh to obtain an Al—Fe alloy powder of 250 mesh or less.

  After 300 g of the obtained Al—Fe alloy powder was stirred and mixed in a 35 mass% sodium hydroxide aqueous solution at 50 ° C. for 1.5 hours, the mixed solution was allowed to stand and the upper layer liquid was removed. The precipitate remaining after removing the upper layer liquid was washed with distilled water until the pH became 10 or less to obtain Al-Fe porous metal powder. Here, the Al—Fe porous metal powder was obtained by a reaction in an aqueous solution in order to avoid contact with oxygen.

  The obtained Al—Fe porous metal powder was vacuum-dried at 200 Pa or less and 80 ° C. to a moisture content of 1% by mass or less, and dried Al—Fe porous metal powder (hereinafter, the Al—Fe porous metal powder was dried). The product is expressed as “metal powder 1”).

(Bulk density)
The bulk density of the obtained metal powder 1 was 1.3 g / cm ³ (measured according to JIS Z2504).

(Oxygen absorption)
1 g of metal powder 1 is packed in a breathable sachet, put in a gas barrier bag (Al foil laminated plastic bag) with a desiccant, filled with 500 mL of air (oxygen concentration 20.9%), sealed, and 25 ° C. And stored for 1 day. As a result of measuring the oxygen concentration in the gas barrier bag stored at 25 ° C. for one day by gas chromatography, the oxygen concentration in the gas barrier bag was 5.9% by volume, and the oxygen absorption amount was calculated from the reduced oxygen concentration in the gas barrier bag. As a result, the oxygen absorption amount was 79.7 mL / g.

(Average particle size)
As a result of measuring the average particle size of the metal powder 1 using a particle size / shape distribution measuring instrument (“PITA-2” manufactured by Seishin Enterprise Co., Ltd.), the average particle size of the metal powder 1 was 45 μm.

(Specific surface area)
As a result of measuring the specific surface area of the metal powder 1 using an automatic specific surface area measuring device (“Gemini VII2390” manufactured by Shimadzu Corporation), the specific surface area of the metal powder 1 was 53.0 m ² / g.

(Preparation of oxygen-absorbing resin composition pellet A)
Metal powder 1 and linear low density polyethylene (available from Nippon Polyethylene, MFR 2.1 g / 10 min (measured according to JIS K7210), hereinafter referred to as “LLDPE1”), LLDPE1: Metal powder 1 = It was melt-kneaded with a twin screw extruder so that the content was 70% by mass: 30% by mass to obtain “oxygen-absorbing resin composition pellet A”.

The density of the oxygen-absorbing resin composition pellet A was 1.25 g / cm ³ . Raw materials were fed into the twin-screw extruder through two types of feeders, a main feeder and a side feeder each replaced with nitrogen gas. LLDPE1 was charged by a main feeder, and metal powder 1 was charged by a side feeder to molten LLDPE1.

(Preparation of oxygen-absorbing resin composition pellet B)
Oxygen-absorbing property except that a random copolymer of polypropylene (available from Prime Polymer Co., Ltd., MFR 7.0 g / 10 min (measured according to JIS K7210), hereinafter referred to as “PP2”) was used instead of LLDPE1. “Oxygen-absorbing resin composition pellet B” was obtained in the same manner as in resin composition pellet A.

The density of the oxygen-absorbing resin composition pellet B was 1.24 g / cm ³ .

(Preparation of oxygen-absorbing resin composition pellets C and D)
As the metal compound, calcium oxide CaO (available from Wako Pure Chemical Industries) was used. Except that CaO and LLDPE1 were LLDPE1: CaO = 30% by mass: 70% by mass, and melt-kneaded by a twin screw extruder by the same operation as the oxygen-absorbing resin composition pellet A, “ Metal compound resin pellet C "was obtained. By the same operation, CaO and PP2 were melt-kneaded with a twin-screw extruder so that PP2: CaO = 30% by mass: 70% by mass to obtain “metal compound resin pellet D”.

The density of the metal compound resin pellet C was 1.80 g / cm ³ . The density of the metal compound resin pellet D was 1.80 g / cm ³ .

[Example 1]
Two types of two-layer films (thickness: oxygen absorption layer 40 μm / thermoplastic resin layer 20 μm) using LLDPE1 as a thermoplastic resin layer were corona discharge treated at a width of 650 mm and 40 m / min. A film roll of an absorption molded body was produced (hereinafter referred to as “oxygen absorption molded body a”). The oxygen absorbing layer was prepared in such a composition that oxygen absorbing resin composition pellets A: metal compound resin pellets C = 97 mass%: 3 mass%. The film roll had no uneven thickness such as bumps, and the appearance of the obtained film was good.

(Oxygen absorption)
The obtained oxygen-absorbing molded product a was cut into 10 cm × 10 cm. The mass of the oxygen-absorbing molded body a cut out is 0.69 g, and when calculated from the mass ratio of LLDPE1 and metal powder 1 in the molded body, the mass of the metal powder 1 contained in the molded body is 0.00. It was 15 g. The molded body was placed in a gas barrier bag (Al foil laminated plastic bag) together with a desiccant, filled with 100 mL of air (oxygen concentration 20.9%), sealed, and stored at 25 ° C. for 30 days.

  As a result of measuring the oxygen concentration in the gas barrier bag stored at 25 ° C. for 30 days by gas chromatography, the oxygen concentration in the gas barrier bag was 15.0% by volume, and the oxygen absorption amount was calculated from the reduced oxygen concentration in the gas barrier bag. As a result, the oxygen absorption amount per unit mass of the metal powder 1 contained in the oxygen-absorbing resin was 47.1 mL / g.

(Theoretical water absorption capacity)
The oxygen absorption molded body a was cut into 21 cm × 30 cm. The mass of the oxygen-absorbing molded body a cut out was 4.34 g. The amount of calcium oxide contained in the molded body was 0.067 g in terms of oxide and 1.5% by mass when calculated from the measurement result of ICP. Since the theoretical water supply capacity of calcium oxide is 32.1% by mass, the theoretical water supply capacity of the oxygen-absorbing molded body a is calculated as 0.5% by mass.

(Water absorption capacity and molar ratio)
Subsequently, the oxygen-absorbed molded body a cut out to 21 cm × 30 cm was stored for 30 days at 40 ° C. and 90% RH under a nitrogen condition with an oxygen concentration of 0.1% or less, and then the mass was measured and the measured mass. From the above, the water absorption capacity of the oxygen absorption molded body a was calculated, and the water absorption capacity of the oxygen absorption molded body a was 0.4% by mass. When the molar ratio of the hydroxide to the oxide of calcium oxide was calculated from the theoretical water supply capacity and water absorption capacity of the oxygen-absorbing molded body a, the molar ratio was 0.25. The results are shown in Table 1.

(Manufacture of oxygen absorption laminated body a)
Using the urethane dry laminate adhesive (manufactured by Mitsui Chemicals Co., Ltd.) on the corona-treated surface side of the produced oxygen-absorbing molded product a, PET (manufactured by Toyobo Co., Ltd., single-sided corona treated, 12) / adhesive ( 3) / Gas barrier layer: Aluminum foil (7) / Adhesive (3) / Oxygen absorption layer (40) / Sealant layer: LLDPE1 (20) An oxygen absorption laminate a was obtained. The numbers in parentheses mean the thickness of each layer (unit: μm).

(Relative humidity)
An oxygen-absorbing packaging container a (9 cm × 12 cm) is produced with the sealant layer of the oxygen-absorbing laminate a inside, and a patch (trade name: Patex Usupita Ship (registered trademark), Daiichi Sankyo Healthcare Co., Ltd. And sealed with heat seal (so that the air amount in the bag is 15 cc) to obtain a sealed body. This sealed body was stored at 23 ° C. and 30 RH%, and when the oxygen concentration on the 14th day was measured by gas chromatography, it was 0.1 vol% or less. In addition, when the relative humidity inside the sealed body after 14 days storage at 23 ° C. and 30 RH% was measured, the relative humidity was 21% RH, which was constant without making the object to be stored inside the sealed body dry. It was possible to store at a low humidity. The results are shown in Table 1.

[Example 2]
A humidity control step was introduced into the film roll of the oxygen absorbing molded body a to produce an oxygen absorbing molded body b. As the humidity control step, the film roll of the oxygen-absorbing molded product a was unwound at 20 m / min, and water vapor was sprayed on the thermoplastic resin layer so as to be 4 mL / m ² . The water vapor was sprayed on the film roll using an ultrasonic humidifier.

(Oxygen absorption)
In the same manner as in Example 1, the oxygen-absorbing molded body b was cut into 10 cm × 10 cm. The mass of the cut oxygen-absorbing molded body b is 0.69 g. When calculated from the mass ratio of LLDPE1 and metal powder 1 in the molded body, the mass of the metal powder 1 contained in the molded body is 0.00. It was 15 g.

  In the same manner as in Example 1, the oxygen absorption amount of the oxygen absorption molded body b was measured. As a result, the oxygen concentration in the gas barrier bag was 15.2% by volume, and the oxygen absorption amount was calculated from the reduced oxygen concentration in the gas barrier bag. As a result of calculation, the oxygen absorption amount per unit mass of the metal powder 1 contained in the oxygen-absorbing resin was 45.6 mL / g.

(Theoretical water absorption capacity)
The oxygen absorption molded body b was cut into 21 cm × 30 cm. The mass of the oxygen-absorbing molded body b cut out was 4.34 g. The amount of calcium oxide contained in the compact was the same as that of the oxygen-absorbing compact a, 0.067 g, and 1.5% by mass. The theoretical water supply capacity of the oxygen-absorbing molded body b is 0.5% by mass, like the oxygen-absorbing molded body a.

(Water absorption capacity and molar ratio)
Subsequently, in the same manner as in Example 1, the water absorption capacity of the oxygen-absorbing molded article b cut out to 21 cm × 30 cm was calculated and found to be 0.1% by mass. Further, when the molar ratio of the hydroxide to the oxide of calcium oxide contained in the oxygen-absorbing molded body b was calculated, the molar ratio was 0.8. The results are shown in Table 1.

(Manufacture of oxygen-absorbing laminate b and oxygen-absorbing packaging container b)
An oxygen-absorbing molded body b was obtained in the same manner as in Example 1 except that the oxygen-absorbing molded body b was used in place of the oxygen-absorbing molded body a, and then an oxygen-absorbing packaging container b was further obtained.

(Relative humidity)
A patch (trade name: Patex Usupita Ship (registered trademark), manufactured by Daiichi Sankyo Healthcare Co., Ltd.) was filled in the oxygen-absorbing packaging container b, and sealed with heat seal to obtain a sealed body. The oxygen concentration after storing this sealed body at 23 ° C. and 30 RH% for 14 days was 0.1% by volume or less. In addition, the relative humidity inside the sealed body after storage for 14 days at 23 ° C. and 30 RH% is 43% RH, and the object to be stored inside the sealed body should be stored under a certain humidity without being dried. Was possible. The results are shown in Table 1.

[Comparative Example 1]
Two types of three-layer film (thickness: thermoplastic resin layer 30 μm / oxygen absorption layer 70 μm / thermoplastic resin layer 30 μm) made of PP2 as a thermoplastic resin layer with a width of 830 mm and a corona discharge on one side at 50 m / min. The film roll of the oxygen absorption molding was processed (it is hereafter described as "oxygen absorption molding c"). The oxygen-absorbing layer was prepared in such a composition that oxygen-absorbing resin composition pellets B: metal compound resin pellets D = 70% by mass: 30% by mass. The film roll had no uneven thickness such as bumps, and the appearance of the obtained film was good.

(Oxygen absorption)
In the same manner as in Example 1, the oxygen-absorbing molded body c was cut into 10 cm × 10 cm. The mass of the cut oxygen absorbing molded body c is 1.53 g. When calculated from the mass ratio of PP2 and the metal powder 1 in the molded body, the mass of the metal powder 1 contained in the molded body is 0.00. It was 21 g.

  When the oxygen absorption amount of the oxygen-absorbing molded body c was measured in the same manner as in Example 1, the oxygen concentration in the gas barrier bag was 12.2% by volume, and the oxygen absorption amount was calculated from the reduced oxygen concentration in the gas barrier bag. As a result of calculation, the oxygen absorption amount per unit mass of the metal powder 1 contained in the oxygen-absorbing resin was 47.9 mL / g.

(Theoretical water absorption capacity)
The oxygen absorption molding c was cut into 21 cm × 30 cm. The mass of the oxygen-absorbing molded product c cut out was 9.61 g. When the amount of calcium oxide contained in the molded body was calculated from the measurement result of ICP, it was 1.304 g in terms of oxide, which was 13.6% by mass. The theoretical water supply capacity of the oxygen-absorbing molded body c is calculated as 4.4% by mass.

(Water absorption capacity and molar ratio)
Subsequently, in the same manner as in Example 1, the water absorption capacity of the oxygen-absorbing molded body c cut into 21 cm × 30 cm was calculated, and it was 3.4% by mass. When the molar ratio of the hydroxide to the oxide of calcium oxide contained in the oxygen-absorbing molded body c was calculated, the molar ratio was 0.23. The results are shown in Table 1.

(Manufacture of oxygen absorption laminated body c)
Using the urethane dry laminate adhesive (manufactured by Toyo Morton Co., Ltd.) on the corona-treated surface side of the produced oxygen absorbing molded product c, PET (manufactured by Toyobo Co., Ltd., single-sided corona treated, 12) / adhesive ( 3) / Gas barrier layer: aluminum foil (7) / adhesive (3) / nylon (manufactured by Toyobo Co., Ltd., double-sided corona treatment, 15) / adhesive (3) / PP2 (30) / oxygen absorbing layer (70 ) / Sealant layer: PP2 (30) oxygen-absorbing laminate c was obtained. The numbers in parentheses mean the thickness of each layer (unit: μm).

(Manufacture of oxygen-absorbing packaging container c)
An oxygen-absorbing packaging container c was obtained in the same manner as in Example 1 except that the oxygen-absorbing laminate c was used instead of the oxygen-absorbing laminate a.

(Relative humidity)
A patch (trade name: Patex Usupita Ship (registered trademark), manufactured by Daiichi Sankyo Healthcare Co., Ltd.) was filled in the oxygen-absorbing packaging container c and sealed with heat seal to obtain a sealed body. The oxygen concentration after storing this sealed body at 23 ° C. and 30 RH% for 14 days was 0.1% by volume or less. Moreover, the relative humidity inside the sealed body after storing for 14 days at 23 ° C. and 30 RH% was 2.0% RH, and the environment for storing the object inside the sealed body became dry.

Claims (6)

Metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a metal compound whose content is 0.1% by mass or more and 20% by mass or less in terms of oxides, A molded body,
The average particle diameter of the metal particles is 5.0 μm or more and 200 μm or less, and the BET specific surface area of the metal particles is 10 m ² / g or more,
The water absorption capacity calculated from the following formula (1) is 3.0% by mass or less.
Oxygen absorption molding.
Water absorption capacity (mass%) = 100 × (M2-M1) / M1 (1)
(In the formula, M1 represents the mass of the molded body, and M2 represents the mass after storing the molded body under the conditions of 40 ° C. and 75% RH.) The metal compound is a metal oxide and a metal hydroxide,
Calculated from the following formula (2), the molar ratio of the metal hydroxide to the metal oxide is 0.5 or more.
The oxygen-absorbing molded article according to claim 1.
Molar ratio = [(B1 × M3 / M1) −A] / A (2)
(In the formula, A represents the water absorption capacity, B1 represents the theoretical water absorption capacity of the metal compound, M1 represents the mass of the molded body, and M3 represents the mass of the metal compound.) Molding metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a metal compound having a content of 0.1% by mass or more and 20% by mass or less in terms of oxide. A molding step for obtaining a molded body;
A humidity control step of bringing 1.0 mL / m ² or more and 40 mL / m ² or less of water vapor into contact with water or applying water to the molded body in terms of liquid water,
A method for producing an oxygen-absorbing molded article. Metal particles containing one or two metals selected from iron and nickel, a thermoplastic resin, and a metal compound whose content is 0.1% by mass or more and 20% by mass or less in terms of oxides, An oxygen absorbing layer;
On one side of the oxygen absorbing layer, one or more thermoplastic resins having a water vapor permeability of 25 μm thickness of 100 g / m ² or less at a temperature of 40 ° C. and a humidity of 90% RH are contained. A sealant layer to
A gas barrier layer is provided on the other surface side of the oxygen absorption layer,
The average particle diameter of the metal particles is 5.0 μm or more and 200 μm or less, and the BET specific surface area of the metal particles is 10 g / m ² / day or more,
Oxygen absorbing laminate. The sealant layer contains a cyclic polyolefin;
The oxygen absorption laminated body of Claim 4. A packaging container comprising at least a part of the oxygen-absorbing laminate according to claim 4 or 5,
The oxygen-absorbing laminate includes an oxygen-absorbing layer in the packaging container, a sealant layer inside the oxygen-absorbing layer, and a gas barrier layer outside the oxygen-absorbing layer.
Oxygen absorbing packaging container.