JP6690201B2 - Oxygen absorber composition and oxygen absorber - Google Patents

Description

  The present invention relates to an oxygen absorber composition and an oxygen absorber. Specifically, it relates to an oxygen absorber composition having a water activity of 0.5 or less and an oxygen absorber prepared by packaging the oxygen absorber composition.

  Conventionally, a deoxidizer utilizing the oxidation reaction of iron powder (hereinafter referred to as an iron-based deoxidizer) has been proposed. Commercially available oxygen scavengers (for example, trade name "Ageless", manufactured by Mitsubishi Gas Chemical Co., Inc.) are used to remove the oxygen in the container by hermetically storing it in a gas barrier container together with products such as foods and pharmaceuticals. It is already widely used to maintain quality and freshness.

  The iron-based oxygen scavengers include a "moisture-dependent" oxygen scavenger that starts absorbing oxygen by utilizing the water that has evaporated from the preserved material, and the oxygen necessary for the oxygen absorption reaction of the iron powder. There are "self-reactive" oxygen scavengers in the composition. When "self-reactive type" oxygen scavengers are used for foods and pharmaceuticals with low water content, the oxygen content of the oxygen scavenger composition is transferred to foods and pharmaceuticals, etc. There were times when it ended up. As a method for solving the problem of water migration, Patent Document 1 discloses an oxygen scavenger composition for low humidity atmosphere having a water content of 1% by weight or less.

JP, 10-309427, A

  However, the composition of Patent Document 1 has a problem that the oxygen absorption performance is remarkably reduced particularly in a low humidity atmosphere of 50% RH or less. The present invention has been made in view of the above circumstances, and provides an oxygen absorber composition having a high oxygen absorption rate even in a low humidity atmosphere of 50% RH or less, and having suppressed water transfer to a substance to be stored. The purpose is to provide.

  As a result of studying a method for solving the above problems, the present inventors have found that in a deoxidizer composition containing iron powder, calcium chloride, water and a water-retaining carrier, the content of water is 20 per 100 parts by mass of iron powder. To 40 parts by mass, and the content of calcium chloride is 52 to 61 parts by mass with respect to 100 parts by mass of water, thereby having excellent oxygen absorption performance even in a low humidity atmosphere of 50% RH or less, and The inventors have found that an oxygen scavenger composition in which water transfer to a preserved product is suppressed can be obtained, and have completed the present invention.

  That is, the present invention is as follows.

[1] In an oxygen scavenger composition containing iron powder, calcium chloride, water and a water-retaining carrier, the water content is 20 to 40 parts by mass with respect to 100 parts by mass of the iron powder, and the calcium chloride content. Is 52 to 61 parts by mass with respect to 100 parts by mass of the water.

[2] The oxygen absorber composition according to [1], which further contains activated carbon.

[3] A method for producing a pouch-shaped oxygen scavenger, which is obtained by packaging the oxygen scavenger composition according to [1] or [2] in a composite film containing a resin layer capable of heat bonding.

[4] A method for producing a canister-shaped oxygen absorber, which is obtained by filling and packaging the oxygen absorber composition according to [1] or [2] in a container containing a thermoplastic resin.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the oxygen scavenger composition which has the outstanding oxygen absorption performance also in the low humidity atmosphere of 50% RH or less, and which suppressed the water transfer to the preservation object.

  Hereinafter, modes for carrying out the present invention (hereinafter, simply 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 and implemented within the scope of the gist.

  The oxygen scavenger composition of the present embodiment is an oxygen scavenger composition containing iron powder, calcium chloride, water and a water-retaining carrier, and the content of water is 20 to 40 parts by mass relative to 100 parts by mass of the iron powder. And the content of the calcium chloride is 52 to 61 parts by mass with respect to 100 parts by mass of the water. By using iron powder, water and calcium chloride in the above mass ratio, it is possible to obtain an oxygen scavenger composition exhibiting excellent oxygen absorption performance even in a low humidity atmosphere of 50% RH or less.

<Iron powder>
The iron powder that is the main agent of the oxygen scavenger is not particularly limited as long as the surface of iron is exposed, and reduced iron powder, electrolytic iron powder, atomized iron powder and the like are preferably used. In addition, crushed products such as cast iron and cut products can be used. As the iron powder, iron powder having an average particle size of 1 mm or less, preferably 500 μm or less, more preferably 100 μm or less is used in order to improve the contact with oxygen. The particle size as used herein means a particle size measured from the weight fraction according to the size of the sieve mesh after being vibrated for 5 minutes using a JIS Z 8801 standard sieve.

<Water and calcium chloride>
Since the iron-based oxygen scavenger requires water in order to exert the oxygen absorption performance, the oxygen scavenger composition of the present embodiment contains water. On the other hand, the oxygen scavenger composition of the present embodiment further contains calcium chloride from the viewpoint of suppressing the migration of water to the preserved substance when it is used as the oxygen scavenger. Calcium chloride is preferably contained as an aqueous solution dissolved in water. The content of water is not only that contained in the composition in a liquid state, but also the weight of water adsorbed on the surface of particles such as water retention carrier and the weight of water contained as hydrated water of hydrate. Calculated as a value that includes all. In addition to anhydrous calcium chloride, commercially available calcium chloride such as calcium chloride dihydrate can be used regardless of whether it is anhydrous or hydrated. The content of calcium chloride is calculated as an anhydride.

  The content of water in the oxygen scavenger composition is 20 to 40 parts by mass, preferably 25 to 35 parts by mass, and more preferably 28 to 32 parts by mass with respect to 100 parts by mass of iron powder. If the content of water is less than 20 parts by mass, the oxidation reaction of the iron powder does not proceed normally, leading to a decrease in the oxygen absorption rate, and if it is more than 40 parts by mass, the content of the iron powder becomes relatively small. Therefore, it is not preferable. By setting the content ratio of iron powder and water in the oxygen scavenger composition within the above preferable range, it is possible to obtain a oxygen scavenger having more excellent oxygen absorption performance.

  The content of calcium chloride in the oxygen scavenger composition is 52 to 61 parts by mass with respect to 100 parts by mass of the water. If the amount of calcium chloride is less than 52 parts by mass, the water activity of the oxygen scavenger composition becomes too high, which is not preferable. On the other hand, if the amount of calcium chloride is more than 61 parts by mass, the solubility of calcium chloride decreases and it becomes difficult to add it as an aqueous solution, which is not preferable from the viewpoint of producing a uniform composition.

<Water retention carrier>
From the viewpoint of improving the handleability of the oxygen absorber composition, the oxygen absorber composition of the present embodiment further contains a water retention carrier. The water retention carrier is not particularly limited as long as it can support water, and known materials such as diatomaceous earth, perlite, zeolite, activated alumina, silica gel, sand and stone can be used. From the viewpoint of the amount of water retention per carrier weight or carrier volume and the price, silica having a porous particle shape, diatomaceous earth, and zeolite are preferable, and precipitating wet silica is more preferable. From the viewpoint of oxygen absorption performance, it is preferable that the pH of the water-retaining carrier when it is made into a water slurry is close to 7.

  The property of the water-retaining carrier is not particularly limited, but a powdery one having high fluidity is preferably used from the viewpoint of handleability during production of the oxygen scavenger to be described later, and one having a shape close to a sphere is more preferred. The particle size of the water retention carrier is preferably 10 to 100 μm, more preferably 30 to 70 μm. If the particle size of the water-retaining carrier is too large, it may cause non-uniformity of the components due to classification, and if it is too small, it may cause scattering during handling, which is not preferable. By setting the particle size of the water-retaining carrier within the above-mentioned preferable range, it is possible to obtain an oxygen scavenger composition having good handleability when producing an oxygen scavenger. The water-retaining carrier particles can be used regardless of whether they are primary particles, agglomerated particles, or granulated particles, as long as they have a particle size within the above-mentioned preferred range. The water-retaining carrier having a particle size in the above range may be used alone or in combination of a plurality of kinds having different particle sizes at an arbitrary ratio.

  The content of the water retention carrier is not particularly limited, but is preferably 20 to 500 parts by mass, and more preferably 30 to 300 parts by mass with respect to 100 parts by mass of water.

<Activated carbon>
Activated carbon can be added to the oxygen scavenger composition of the present embodiment as a reaction accelerator, if necessary. The activated carbon used may be wood, coconut shell, coal or the like. Although the content of the activated carbon is not particularly limited, it is preferably 5% by mass or less and more preferably 2% by mass or less with respect to the total amount of the oxygen absorber composition. By containing activated carbon, the oxygen absorbing performance of the oxygen absorber composition in a low humidity atmosphere of 50% RH or less is further improved.

<Method for producing oxygen absorber composition>
The oxygen scavenger composition of the present embodiment can be manufactured by the steps shown below, but is not limited thereto. A uniform oxygen absorber composition can be produced by the following steps.
<1> A step of dissolving calcium chloride in water <2> A step of supporting an aqueous solution prepared by the step <1> on a water retention carrier <3> A step of adding iron powder to the water retention carrier prepared by the step <2> and mixing

<Package form of oxygen absorber>
The oxygen scavenger composition of this embodiment is packaged in various forms and used for maintaining the quality and freshness of foods, pharmaceuticals and the like. Examples of the packaging form of the oxygen scavenger include, but are not limited to, a pouch-type packaging with a multilayer film including a heat-bondable resin layer, and a canister form by filling and packaging in a thermoplastic resin container.

<Pouch type oxygen absorber>
In the present embodiment, a pouch-type oxygen scavenger can be formed by packaging the oxygen scavenger composition with a multilayer film including a heat-bondable resin layer. The multilayer film is not particularly limited as long as a heat-bondable layer (hereinafter, sealant layer) is provided on the side in contact with the oxygen absorber composition, but the oxygen absorber composition to be contained is outside the packaging bag. A highly breathable multilayer film that does not leak and has a sufficient oxygen absorbing effect is preferably used. For example, a multi-layer film in which papers such as Japanese paper, western paper, rayon paper, pulp, cellulose, and non-woven fabrics using various fibers such as fibers from synthetic resin are laminated with a perforated sealant layer, and more preferably, Further, a multilayer film in which a heat-resistant resin film such as perforated polyester, polyamide, or polyvinylidene chloride is laminated on the side opposite to the sealant layer can be used. The sealant layer is not particularly limited as long as it has sufficient heat seal strength when heat-bonded, and a polyolefin resin film such as low density polyethylene, linear low density polyethylene (hereinafter, LLDPE), unstretched polypropylene and the like; Copolymer films of ethylene vinyl acetate copolymer, ethylene methacrylic acid copolymer, ethylene acrylic acid copolymer, ethylene methyl acrylate and the like; commercially available products such as Ionomer (trademark) can be used.

Filling and packaging form of the sachet-type oxygen scavenger can be a known packaging form such as pillow packaging form, three-way sealing packaging form, four-side sealing packaging form, etc., respectively, stick packer, rotary packer, four-way filling packaging machine, etc. Filling and packaging can be performed using a known filling and packaging machine.

<Canister type oxygen absorber>
In this embodiment, a canister type oxygen absorber can be formed by filling and packaging the oxygen absorber composition in a canister type container. As the canister type container, a thermoplastic resin container is preferable. As the thermoplastic resin container, a container made of polyolefin such as low density polyethylene, high density polyethylene or polypropylene; a container made of chlorinated polyolefin such as polyvinyl chloride or polyvinylidene chloride; a container made of polyester such as polyethylene terephthalate (hereinafter PET); A known container such as a container made of a copolymer such as an ethylene-vinyl acetate copolymer, an ethylene-methyl methacrylate copolymer, or a cyclic olefin copolymer can be used. From the viewpoints of price, impact resistance, safety, heat resistance, processability, etc., a polyolefin container or a chlorinated polyolefin container is more preferable, and a polypropylene container or a polyvinyl chloride container is further preferable.

<Oxygen absorption performance of oxygen absorber>
The oxygen absorption performance of the oxygen scavenger of the present embodiment is evaluated by the oxygen removal time and the oxygen absorption amount as an index showing the oxygen absorption rate. The deoxidizing time means that when a certain volume of air and an oxygen scavenger are co-sealed in the oxygen barrier bag, the oxygen scavenger absorbs oxygen in the oxygen barrier bag and the concentration in the bag is less than 0.1% by volume. The oxygen absorption amount is derived from the oxygen concentration in the bag measured after enclosing the excess oxygen and oxygen scavenger in an oxygen barrier bag and storing it for a certain period of time. The amount of oxygen reduction in the bag.

<Moisture migration from oxygen absorber>
When the oxygen scavenger of the present embodiment is used for storage of foods and pharmaceuticals, it is possible to minimize the transfer of water contained in the oxygen scavenger composition to the stored product. The degree of water migration can be evaluated by measuring the water activity of the oxygen absorber composition and the water activity of the stored material. The method for measuring the water activity is not particularly limited, and it can be measured using a known device such as a dew point water activity measuring device.

  Examples of the present invention will be shown below and will be described more specifically. The present invention is not limited to these examples.

  In the following examples, reagents made by Wako Pure Chemical Industries, Ltd. were used for iron powder, calcium chloride anhydrous, activated carbon, and calcium hydroxide.

(Example 1)
<Preparation of oxygen absorber composition>
An aqueous solution was prepared by dissolving 25 g of calcium chloride dihydrate in 25 g of water. This was added to and mixed with 20 g of precipitating wet silica which is a water retention carrier to obtain a moisture donor.
An oxygen absorber composition was obtained by mixing 100 g of iron powder with 100 g of iron powder and adding 1.0 g of activated carbon.

<Evaluation of water activity of oxygen absorber composition>
The water activity of the obtained oxygen scavenger composition was evaluated using a dew point water activity measuring device. The water activity of the oxygen absorber composition at 25 ° C. was 0.45.

<Preparation of sachet type oxygen absorber>
Width 20 mm x pitch 40 mm, lower seal width and spine sticker width so that the LLDPE is on the inside by using a multi-layered sheet of LLDPE (thickness 30 μm) / paper (weight per unit area 50 g / m ² ) / PET (thickness 12 μm) A pillow packaging bag having a size of 5 mm was produced. The pillow packaging bag was filled with 1.0 g of the oxygen scavenger composition, and the upper end of the pillow packaging bag was heat-bonded so as to have an upper seal width of 5 mm to obtain an evaluation sample.

<Evaluation of oxygen absorption of sachet type oxygen absorber>
The pouch type oxygen absorber sample prepared as described above was enclosed in a barrier bag together with 1.0 L of air, and the ends were heat-bonded and sealed. The barrier bag was stored at 25 ° C. for 14 days, and the oxygen concentration in the bag was measured with a zirconia oxygen analyzer. As a result of calculating the oxygen absorption amount from the difference in concentration with the atmospheric oxygen concentration, it was 59 mL.

(Example 2 and Comparative Examples 1 to 4)
An experiment was conducted in the same manner as in Example 1 except that the composition shown in Table 1 was used. The results are shown in Table 1.

  As is clear from Table 1, in Examples 1 and 2, the water activity was 0.5 or less, and it was confirmed that the calcium chloride aqueous solution was easily prepared and the oxygen absorption performance was good. . On the other hand, in Comparative Examples 1 and 2, it was confirmed that it was difficult to prepare an aqueous calcium chloride solution, and in Comparative Examples 3 and 4, the water activity exceeded 0.5, which was not preferable from the viewpoint of water migration to foods and the like. .

(Example 3)
<Preparation of canister type oxygen absorber>
A polypropylene container shown in FIG. 1 was filled with 1.0 g of the same oxygen scavenger composition as in Example 1, and a lid member made of a multi-layer sheet of PET (thickness 12 μm) / cardboard (weight per unit area 150 g / m ² ). Was crimped into a canister shape so that the paper side was the inside of the canister (the bulk powder side), and this was used as the evaluation sample.

<Evaluation of oxygen absorption amount of canister type oxygen absorber>
The oxygen absorption amount of the canister-type oxygen absorber prepared as described above was 56 mL as a result of the same method as the evaluation of the oxygen absorption amount of the pouch-type oxygen absorber.

  According to the present invention, an oxygen scavenger composition having excellent oxygen absorption performance even in a low humidity atmosphere of 50% RH or less and having less migration of water to an article to be stored is provided. In particular, an oxygen scavenger composition suitable for storage of foods such as dried foods and rice crackers that do not like water, and medicines such as tablets and powders that deteriorate due to water is provided at a low price. This makes it possible to effectively use a deoxidizer having an excellent oxygen absorption performance for foods and pharmaceuticals to which a high water activity deoxidizer could not be applied due to the concern of water migration.

Claims (5)

  In the oxygen scavenger composition containing iron powder, calcium chloride, water and a water retention carrier, the content of the water is 20 to 40 parts by mass relative to 100 parts by mass of the iron powder, and the content of the calcium chloride is the water. An oxygen absorber composition whose amount is 52 to 61 parts by mass with respect to 100 parts by mass.   The oxygen scavenger composition according to claim 1, further comprising activated carbon.   The oxygen scavenger composition according to claim 1 or 2, wherein the calcium chloride is contained as an aqueous solution dissolved in water. A method for producing a pouch-shaped oxygen scavenger, which comprises packaging the oxygen scavenger composition according to claim 1 in a composite film containing a resin layer capable of heat bonding. A method for producing a canister-shaped oxygen absorber, which comprises filling and packaging the oxygen absorber composition according to any one of claims 1 to 3 in a container containing a thermoplastic resin.