JP3252866B2 - Oxygen absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various foods, pharmaceuticals, etc.
The present invention relates to an oxygen absorbent used for maintaining quality of various objects. More specifically, an oxygen absorbent comprising a water donor containing water in diatomaceous earth having an adsorption characteristic of exhibiting a relative humidity of 55% or more when containing 2% of iron powder, an oxidation promoting substance, filler and water. About.

[0002]

2. Description of the Related Art As one of food preserving techniques, the use of an oxygen absorbent package in which an oxygen absorbent is packaged with a breathable material has been widely used. Recently, there have been many types of articles that are subject to oxygen absorber packaging, including food.
Moreover, it is diversifying. In order to easily store the oxygen absorbent package in various storage containers or packaging bags containing these storage objects and to make the oxygen absorbent package more compact, there is a demand for the development of an oxygen absorbent having a smaller amount and a higher oxygen absorption capacity. On the other hand, the use thereof is expanding to inexpensive foods and the like, and the market demand for an oxygen absorbent package having a lower cost is increasing. In view of these demands, the present inventors have improved the oxygen absorber by focusing on the moisture donor in the oxygen absorber,
The excellent oxygen absorbent of the present invention was successfully developed.

[0003] Conventionally, as a technique relating to a moisture donor of an oxygen absorbent, Japanese Patent Publication No. 56-61818 discloses an oxygen absorbent obtained by encapsulating an iron powder coated with a metal halide and a water-containing substance in a gas-permeable packing material. It has been disclosed. In the same publication, as a water-containing substance, a substance obtained by impregnating granular materials such as diatomaceous earth, perlite, zeolite, activated alumina, activated carbon, sand, activated clay and the like with water or a humidity control liquid is mentioned.

[0004] The water-containing substance, which is one component of the oxygen absorbent, serves as a so-called water donor, supplying water necessary for the oxygen absorption reaction of the iron powder as the base material. Therefore, an adsorbent substance having a large water retention amount is selected as the water carrier used for the water donor. In addition, simply having a large amount of water retention is not appropriate and must have sufficient absorption capacity. From the viewpoint of safety and health, for example, when an oxygen absorbent is applied to a food containing a large amount of water, it must not absorb water evaporating from the food and exude moisture. In addition, the fluidity of the granular carrier is also important to enable automatic filling and packaging of the oxygen absorbent. Even though many water-containing substances are known in the same publication, their performances are not always satisfactory, and none other than zeolite, silica gel and pearlite have been put to practical use.

For example, the most frequently used zeolite has the disadvantage that even if the amount of retained water is large, the water is not used effectively. That is, since the equilibrium humidity rapidly decreases at a relatively high water content (see FIG. 1), the retained moisture no longer evaporates sufficiently and does not contribute to the oxygen absorption reaction. For this reason, a problem that oxygen absorption stops on the way also occurs. In order to prevent such troubles beforehand, it was necessary to use a large amount of the carrier to contain sufficient water for the oxide absorption reaction. As described above, the conventional carrier requires a large amount of the carrier, and as a result, the amount of the oxygen absorbent tends to increase. As a result, it is difficult to reduce the size of the oxygen absorbent package, and there is a point to be improved here. In addition, zeolite has a cation exchange ability, so that the pH of the water donor hardly rises even when an alkali substance is added, and the oxygen absorber, which is a main agent of iron powder, relatively suppresses the generation of hydrogen during storage. There was also a problem that it was difficult.

[0006] On the other hand, diatomaceous earth has been known to have good water absorbency, but it has a peculiar odor and has been pointed out to have a problem of fragrance retention when enclosed with foods and the like. I couldn't. In particular, there was no granular material usable as an oxygen absorbent. The present inventors have conducted various studies on various diatomaceous earths, which were not practically neglected in the past, focusing on the adsorption characteristics of water.As a result, the inventors have found that diatomaceous earth can be used as an excellent water donor of an oxygen absorbent. The inventors have found the present invention.

[0007]

An object of the present invention is to solve the above-mentioned problems of the conventional oxygen absorbent using a water-containing substance by using diatomaceous earth as a water donor, and to reduce the amount of the carrier. Accordingly, it is an object of the present invention to provide a practically excellent oxygen absorbent capable of forming a compact oxygen absorbent package having a high oxygen absorption capacity and a low cost.

[0008]

The oxygen absorbent according to the present invention is obtained by adding water to diatomaceous earth having an adsorption characteristic of exhibiting a relative humidity of 55% or more when containing 2% of iron powder, oxidation promoting substance, filler and water. It is characterized by comprising a moisture donor. Hereinafter, the present invention will be described in detail. The iron powder used as the main component in the oxygen absorbent of the present invention can be used without any particular limitation as long as it can exhibit an oxygen absorbing function.
For example, pure iron powder, cast iron powder, steel powder, reduced iron powder, spray iron powder,
Sponge iron powder, electrolytic iron powder and the like.

As the oxidation promoting substance, halides of alkali metals or alkaline earth metals, halides of ion exchange resins, hydrochloric acid, hypochlorite and the like can be used. NaCl, CaC from the oxidation promotion effect, safety and health, etc.
Use of alkali metal or alkaline earth metal halides exemplified by l ₂ , MgCl _{2 and the} like is preferred. The amount of the oxidation promoting substance to be used for the iron powder is in the range of 0.01 to 20 parts by weight based on 100 parts by weight of the iron powder. The method for adding the oxidation promoting substance is not particularly limited, and the oxidation promoting substance may be directly mixed with the oxygen absorbent or added as an aqueous solution. It is a more effective and preferable method to add separately to the water donor side and the iron powder side.

The filler is added for the purpose of improving the fluidity of the oxygen absorbent, suppressing dust, removing off-flavors, suppressing the generation of hydrogen from iron powder, and the like. Specifically, activated carbon, calcium carbonate, perlite, zeolite, activated alumina, iron oxide, hydroxides of alkaline earth metals, gypsum and the like are appropriately selected as necessary.

The water donor of the oxygen absorbent of the present invention is obtained by impregnating diatomaceous earth with water or a humidity control liquid, and has an adsorption characteristic of showing a relative humidity of 55% or more when diatomaceous earth contains 2% water. Things. According to the diatomaceous earth having such adsorption characteristics, as is clear from FIG. 1 showing the relationship between the moisture content and the equilibrium humidity, even when the moisture content is low, which was not seen in the conventional carrier, the moisture is sufficiently evaporated and retained. The water thus added effectively contributes to the oxygen absorption reaction. Diatomaceous earth has different physical properties depending on its type, production method, and treatment. Therefore, it is important to appropriately select diatomaceous earth according to the purpose.

Diatomaceous earth is generally obtained by crushing, drying, and crushing diatomaceous earth produced by the deposition of marine diatoms or freshwater diatoms.
A fired one is used. As marine diatoms, the genus Amaryllidaceae Koshinodiscus, Actinokircus genus,
The genus Stefanopyxis, the genus Cockenais, and the like of freshwater diatoms include the genus Melosila, the genus Cycroterra, the genus Stefanodiscus, and the like. In the present invention, marine diatomaceous earth is preferred, and diatomaceous earth derived from the marine diatom, Lymnaea genus Koshinodiscus, is more preferred.

In the present invention, a powdery or granular diatomaceous earth which has been calcined is used. The temperature of the baking treatment is 500 ° C. or more and less than 1500 ° C., preferably 650 to 1,300 ° C.
Range. In the calcination treatment, if the calcination temperature is low, the odor peculiar to diatomaceous earth is large and not suitable for an oxygen absorbent. If the temperature is lower than 500 ° C., the relative humidity is 55% or more when the required moisture content is 2%. Adsorption characteristics cannot be obtained. On the other hand, when the temperature is higher than 1,300 ° C., the pores of the diatomaceous earth are crushed, so that a desired pore volume cannot be obtained, and the required water content cannot be maintained. When granular diatomaceous earth is required, any of powdered diatomaceous earth fired after granulation or granulated after firing may be used. Preferably, granular diatomaceous earth which has been subjected to wet extrusion granulation of diatomaceous earth before or after drying treatment and then calcined is used.

The particulate diatomaceous earth has a particle size of 0.2 to 3 mm in order to secure fluidity when filling and packing in a gas-permeable package.
Is used, and more preferably, 0.5 to 2 mm is used. In the present invention, fluidity during water retention is particularly important. For example, a fluid having a large water retention capacity is used by evaluating the fluidity by the test method described in Example 1. In the case of powdered diatomaceous earth, after mixing other components of the oxygen absorber, including the iron powder of the main agent, with the powdered diatomaceous earth,
It can be used after granulation.

The diatomaceous earth according to the present invention must have a large pore volume as a water carrier, and the pore volume is 0.1 ml / g or more, preferably 0.3 ml / g or more. In addition, diatomaceous earth is preferably diatomaceous earth having a large amount of water transpiration since water retained as a water donor is efficiently consumed in the oxygen absorption reaction. For this purpose, it is preferable that the diatomaceous earth has a large pore size in the range of 500 to 10,000 nm. In this case, pores having a pore diameter of less than 500 nm have low transpiration of retained moisture and are not very effective. On the other hand, pores larger than 10,000 nm are likely to have an oxygen absorber applied to high moisture foods.
It is not effective because it cannot retain moisture and causes wet rust to seep onto the surface of the packaging material. The specific surface area of the diatomaceous earth is 0.1 to 100 m ² / g, preferably 1 to 50 m ² / g.
Those in the range of ² / g are preferred.

Further, as a property of diatomaceous earth, in order to suppress the generation of hydrogen during storage of the oxygen absorbent, which is the main component of iron powder, the ion exchange capacity is as small as possible,
Adjustable ones are preferred. Specifically, diatomaceous earth having an ion exchange capacity of 50 meq / 100 g or less is used.

In the present invention, diatomaceous earth having an adsorption characteristic of exhibiting a relative humidity of 55% or more when containing 2% of water is impregnated with water or a variety of humidity control liquids such as an aqueous metal halide solution and an aqueous alcohol solution. Yields a moisture donor. The amount of liquid carried is in the range of 45 to 250 parts by weight, preferably 50 to 200 parts by weight, as water with respect to 100 parts by weight of diatomaceous earth. The humidity adjusted as the moisture donor is set to a relative humidity of 55 to secure an appropriate oxygen absorption rate.
% Or more is preferable.

Next, a method for producing the oxygen absorbent of the present invention will be described. According to the present invention, iron powder, oxidation promoting substance, filler
A diatomaceous earth having an adsorption property of indicating a relative humidity of 55% or more when containing 2% of water and a diatomaceous earth may be used as long as it is a production method utilizing characteristics of diatomaceous earth, and is not particularly limited to the following production method.

For example, there is a method in which an oxygen-absorbing main agent composed of iron powder and a water donor composed of diatomaceous earth are individually prepared, and both are mixed. First, iron powder and an aqueous solution of a metal halide as an oxidation promoting substance are mixed and dried, and after coating the metal powder on the iron powder, a filler such as activated carbon is mixed to produce an oxygen-absorbing main agent. The oxygen-absorbing main agent may be a simple mixture of iron powder, powder of an oxidation promoting substance, and a filler. On the other hand, diatomaceous earth having the above characteristics is impregnated with water or a metal halide aqueous solution, and if necessary, coated or mixed with a filler such as activated carbon or a hydroxide of an alkaline earth metal such as slaked lime, etc. To manufacture. Then, in producing the oxygen absorbent package, the oxygen absorbent main agent and the moisture donor are mixed and filled into a gas-permeable packaging material for packaging. In the case of this production method, it is preferable that the oxygen-absorbing main agent and the water donor have fluidity during automatic filling and packaging, and the iron powder and the diatomaceous earth each have a granular form.

Further, after mixing iron powder, oxidation promoting substance, diatomaceous earth, filler, alkali, etc., the mixture is impregnated with water or a humidity control liquid to adjust the humidity, and if necessary, compression molded and granulated. A method using an oxygen absorbent is also possible.

The oxygen absorbent of the present invention is usually packaged in a breathable material and used as an oxygen absorbent package. As a breathable material, it has appropriate oxygen permeability and moisture permeability,
Materials that repel water and oil are selected as needed. Specifically, the package is made of, for example, a material such as paper, plastic film, nonwoven fabric, or microporous film, and a laminated material or a perforated material is used as necessary. As a breathable material, oxygen permeability is 5,000 to 5,
The concentration of 1,000,000 ml / m ² · atm · Day and the moisture permeability of 1 to 5,000 ml / m ² · atm · Day are suitable.

[0022]

Next, the present invention will be described in more detail with reference to examples.
Note that the present invention is not limited to these examples.

Example 1 Diatomaceous earth derived from diatoms belonging to the genus Kashinodiscus sp. Was wet granulated and calcined at 800 ° C. to prepare granular diatomaceous earth having a particle diameter of 0.1 to 1.5 mm. The moisture content and relative humidity of this calcined granular diatomaceous earth when saturated saline was held were measured by the following methods. First, 0.05 g, 0.08 g, 0.1 g, and 0.2 g of a saturated saline solution were added to 5 g of each of the calcined diatomaceous earth particles, respectively.
g, a sample containing 0.5 g and a saline solution not added,
Six kinds were prepared. The water activity (relative humidity,%) of each sample was measured with a water activity meter. Each sample was kept at 120 ° C ± 5 ° C.
The sample was dried for 15 hours in a thermostat adjusted to the above, and the water content of the sample was calculated from the loss on drying. The results are shown in FIG. 1 as the relationship between the water content and the relative humidity.

Comparative Example 1 A diatomaceous earth derived from a diatom belonging to the genus Kashinodiscus of the genus Lymnaea was wet-granulated and dried, and unfired granular diatomaceous earth having a particle size of 0.1 to 1.5 mm was obtained in Example 1. In the same manner as described above, the water content and the relative humidity when a saturated saline solution was held were measured. The results are shown in FIG.

Comparative Example 2 The particle size of the oxygen absorbent used in Comparative Example 4 was 0.5 to 0.5.
For 1.5 mm zeolite, as in Example 1,
The relationship between water content and relative humidity was investigated. To each 5 g of the granular zeolite, 0.05 g of a saturated saline solution and 0.08
g, 0.1 g, 0.2 g, and 0.5 g were prepared, and six samples were prepared without adding saline. The water activity (relative humidity,%) and water content of each sample were measured in the same manner as in Example 1, and the results are shown in FIG.

According to FIG. 1, the granular diatomaceous earth of the present invention calcined at 800 ° C. (Example 1) has a relative humidity of 60% or more at a water- containing (water-containing) concentration of 1% or more. This is because the calcined granular diatomaceous earth has a moisture content of only 1
% Indicates that the oxygen absorbent exhibits sufficient humidity to function effectively even when the water content is as low as about%, that is, the water can be evaporated. In contrast, in the case of granular zeolite, which is to indicate more than 60% relative humidity, it is necessary to the water concentration in the more than 7% (Comparative Example
2) Even in the case of unfired diatomaceous earth, zeolite
Indicating the need of comparable water content to that of (Comparative Example 1). This indicates that the diatomaceous earth of the present invention is an excellent water donor of the oxygen absorbent, and it is known that such characteristics of the diatomaceous earth are imparted by the calcination treatment.

Example 2 100 g of iron powder was mixed with 2 g of a 50 wt% calcium chloride solution, mixed well, and then dried in a drier to obtain a metal halide-coated iron powder. According to a 12-hour loss on drying method, the water content was 5 wt% or less, and the apparent density was 2.7 g / ml. This granular diatomaceous earth 1 prepared in Example 1 and calcined at 800 ° C.
100 g of 25% saline was added to 00 g and mixed. All saline was carried on diatomaceous earth and was free flowing (water retention amount: 75 g / 100 g). Also in the fluidity test described below, it was confirmed that the maintain sufficient fluidity. Next, 1 g of powdered activated carbon having a mesh size of 100 mesh or less was mixed with the granular diatomaceous earth supporting a saline solution to coat the surface, and this was used as a moisture donor. The apparent density of this is 0.75g
/ Ml. After mixing well the resulting halogenated metal-coated iron powder 1g and brine moisture donor 0.75g consisting granular diatomaceous earth having a surface coated with a powdered activated carbon is supported, enclosed perforated polyethylene film laminated with paper bags Then, an oxygen absorbent package was obtained. The oxygen-absorbing package was sealed in a K-coated nylon / polyethylene laminated film outer bag together with 2 liters of air and kept at 25 ° C. When the oxygen concentration in the bag was analyzed 72 hours later, the oxygen concentration was 8%. In this case, the oxygen absorption amount of the oxygen absorbent (1 g of the metal halide-coated iron powder) is 283.
Calculated as ml. No particular abnormality was observed in the appearance of the packaging material constituting the oxygen absorbent package .

[Fluidity test method] The relationship between the water retention of the carrier and the fluidity is examined by the following test method, and the water retention of the carrier is evaluated. A predetermined amount of water is added to 100 g of the carrier and mixed to prepare a water retention agent. The prepared water retention agent is placed in a glass legless funnel (cut off the funnel legs) which is placed on a horizontal table and the lower outlet is blocked. Then, when the glass-made funnel containing the water retention agent is lifted and the lower outlet is separated from the table, the fluidity is determined by whether the water retention agent in the funnel smoothly flows out from the lower mouth and falls. In this method,
Even if the amount of water added to the carrier is increased, it does not flow out, or does not clog in the middle of flowing out, with the maximum amount of added water that can flow smoothly and maintain fluidity, The water retention capacity of the carrier. As the carrier, a carrier having a larger water retention amount and a higher fluidity, that is, a carrier having a higher water retention capacity, has a higher water retention capacity.

Comparative Example 3 Diatomaceous earth derived from diatoms belonging to the genus Kashinodiscus species of the genus Lymnaea is wet-granulated and calcined at 1,500 ° C. to 100 g of diatomaceous earth having a particle size of 0.1 to 1.5 mm.
% Saline was added. However, about 50% of the added saline remained unabsorbed. And the granular diatomaceous earth containing the saline solution was sticky, and it was not necessary to examine the fluidity.

Comparative Example 4 2 g / 100 g of granular zeolite having a particle size of 0.5 to 1.5 mm
Even when 100 g of a 5% saline solution was added and mixed, about 50% of the added saline solution was not retained in the zeolite but remained in a liquid state. According to the water retention test, the particle size is 0.5 to 1.5.
mm zeolite has a water retention capacity of granular zeolite 1
The amount of water was 40 g with 25% saline for 00 g (the water retention of the granular zeolite was 30 g / 100 g).

Then, after holding 40 g of 25% saline in 100 g of granular zeolite having a particle size of 0.5 to 1.5 mm, 1 g of powdered activated carbon having a mesh size of 100 mesh or less is mixed and the surface is coated to obtain a water donor. Was. However, the apparent density was 0.8 g / ml. A water donor consisting of granular zeolite carrying 1.0 g of the same metal halide-coated iron powder as in Example 2 and a saline solution and coated with activated carbon powder.
After well mixing 8 g, the mixture was sealed in a paper bag laminated with a perforated polyethylene film to obtain an oxygen absorbent package.
This oxygen-absorbing package was sealed in a bag with a K-coated nylon / polyethylene laminated film exterior together with 2 liters of air in the same manner as in Example 2, kept at 25 ° C., and analyzed for oxygen concentration in the bag after 72 hours. The oxygen concentration in the system was 13%, and the oxygen absorption amount of the oxygen absorbent (1 g of the metal halide-coated iron powder) in this case was 184 ml. in this case,
To reduce the oxygen concentration to the same level as in Example 2, 1.3 g of a water donor composed of granular zeolite was required.

In Comparative Example 4, when the same volume of water donor was used for the same amount of iron powder as in Example 2, the result was much worse than in Example 2. This is not only due to the difference in water retention between the granular zeolite and the calcined granular diatomaceous earth, but also because the granular zeolite has about 7% of water that does not contribute to oxygen absorption.

Example 3 A water donor was prepared by adding 0.08 g of saturated saline to 5 g of the calcined diatomaceous earth having a particle size of 0.5 to 1.5 mm obtained in Example 1 (water content: 1.5 wt%). . After mixing 1 g of this moisture donor and 1 g of the metal halide-coated iron powder of Example 2, the mixture was sealed in a paper bag laminated with a perforated polyethylene film to obtain an oxygen absorbent package. This oxygen-absorbing package was sealed in a bag with a K-coated nylon / polyethylene laminated film exterior together with 100 ml of air and kept at 25 ° C. When the oxygen concentration in the bag was analyzed 24 hours later, the oxygen concentration in the system was 0.1% or less.

Comparative Example 5 A water donor was prepared by adding 0.08 g of saturated saline to 5 g of zeolite having a particle size of 0.5 to 1.5 mm (water content: 6.1 wt%). After mixing 1 g of the moisture donor and 1 g of the metal halide-coated iron powder of Example 2, the mixture was sealed in a paper bag laminated with a perforated polyethylene film to obtain an oxygen-absorbing package. This oxygen-absorbing package was sealed in a bag of a K-coated nylon / polyethylene laminated film together with 100 ml of air and kept at 25 ° C in the same manner as in Example 3.
Four hours later, when the oxygen concentration in the bag was analyzed, the oxygen concentration in the system was 20.8%. In Example 3, the treated diatomaceous earth sufficiently absorbed oxygen at a water content of 1.5%, whereas Comparative Example 5 did not absorb oxygen at all regardless of the water content of 6.1% zeolite.

Example 4 100 g of the calcined diatomaceous earth having a particle size of 0.5 to 1.5 mm of Example 1 was added with 100 g of 25% saline and mixed, and then 1 g of powdered activated carbon having a mesh size of 100 mesh or less was added. 1 g of powdered magnesium hydroxide having a mesh or less was added, and the surface was coated to prepare a moisture donor. This had an apparent density of 0.7 g / ml. Also, 100 g of pure water is poured into 5 g of the water donor to suspend the suspension, and p
When H was measured, it was pH 9.5. After 10 g of the water donor obtained by adding a saline solution to granular diatomaceous earth and 10 g of the metal halide-coated iron powder of Example 2 were mixed well, the mixture was placed in a paper bag laminated with perforated polyethylene and used as an oxygen absorbent. The oxygen absorbent was sealed in an aluminum-deposited film bag together with 25 ml of air and kept at 35 ° C. After 72 hours, the hydrogen concentration in the bag was analyzed. As a result, the hydrogen concentration in the system was 0.2%.

Comparative Example 5 25% in 100 g of zeolite having a particle size of 0.5 to 1.5 mm
After adding and mixing 40 g of a saline solution, 1 g of powdered activated carbon having a mesh size of 100 mesh or less and 1 g of magnesium hydroxide powdering having a mesh size of 100 mesh or less were further added to coat the surface to prepare a water donor. The apparent density of this is 0.8 g / ml
Met. Further, 100 g of pure water was poured into 5 g of the water donor to suspend the suspension, and the pH of the supernatant was measured.
H8.5. After 10 g of the water donor prepared by adding granular saline to the granular zeolite and 10 g of the metal halide-coated iron powder of Example 2 were mixed well, the mixture was placed in a paper bag laminated with perforated polyethylene to obtain an oxygen absorbent package. This oxygen absorbent package was sealed in an aluminum vapor-deposited film bag together with 25 ml of air and kept at 35 ° C. as in Example 4, and after 72 hours, the hydrogen concentration in the bag was analyzed. Was 4.2%.

Example 5 1 g of the moisture donor prepared in Example 4 and 1 g of the metal halide-coated iron powder of Example 2 were mixed, and the mixture was filled in a paper bag laminated with perforated polyethylene, and the oxygen absorbent package was used. did. The oxygen absorbent package was placed in a K-coated nylon / polyethylene laminated film packaging bag containing 200 g of castella, sealed with 150 ml of air, and stored at room temperature. One day later, when the oxygen concentration in the bag was measured,
Oxygen was absorbed to a concentration of 0.01% or less. When the storage was continued as it was and opened and inspected two weeks later, the quality of the castella was well maintained. No abnormality was found in the appearance of the oxygen absorbent package.

Comparative Example 6 Diatomaceous earth derived from the freshwater diatom Stefanodiscus sp. Was wet granulated and calcined at about 1,000 ° C.
100 g of granular diatomaceous earth of ~ 1.5 mm in 25% saline 10
After adding and mixing 0 g, a water donor was obtained whose surface was coated with 1 g of powdered activated carbon of 100 mesh or less. Apparent density thereof was 0.6 g / ml. 1 g of a water donor comprising the above granular diatomaceous earth derived from the freshwater diatom Stefanodiscus and the metal halide-coated iron powder 1 of Example 2
g, and then mixed well with a paper bag laminated with a perforated polyethylene film to obtain an oxygen absorbent package.
The oxygen absorber package, in the same manner as in Example 5, placed in a packaging bag K coat nylon / polyethylene laminated film housing the sponge cake 200 g, and <br/> enclosed sealed with air 150 ml, and stored at room temperature . One day later, when the oxygen concentration in the bag was measured, the oxygen was absorbed to a concentration of 0.01% or less. The storage was continued as it was, and opened and inspected two weeks later. As a result, the quality of the castella was well maintained.
However, the exudation of the content was slightly observed on the outer surface of the oxygen absorbent package.

[0039]

The oxygen absorber according to the present invention is obtained by impregnating water or a humidifying liquid into diatomaceous earth having an adsorption characteristic of exhibiting a relative humidity of 55% or more when containing 2% of iron powder, oxidation promoting substance, filler and water. It is an excellent oxygen absorbent consisting of a water donor. The diatomaceous earth having the specific adsorption characteristics according to the present invention has a high water retention, and the water is sufficiently evaporated even at a low water content that is not present in conventional carriers, and the retained water can effectively contribute to the oxygen absorption reaction. Yes, and it is cheap. Therefore, by using this diatomaceous earth as a component of the oxygen absorbent as a moisture donor, the amount of the carrier can be greatly reduced, and the oxygen absorbent having a large oxygen absorbing capacity per oxygen absorbent capacity can be obtained. become. in addition,
The oxygen absorbent of the present invention using diatomaceous earth has good scent retention, generates little hydrogen during storage, does not wet or exude even when applied to high moisture foods, and is excellent in safety and hygiene. That is, according to the present invention, it is possible to form a compact oxygen absorbent package having a small amount of carrier, high oxygen absorption capacity, good storage capacity, excellent safety and hygiene, and economical cost reduction. It is possible to provide a cheap and practically excellent oxygen absorbent. Further, the oxygen absorbent according to the present invention can be suitably used for maintaining the quality of a wide range of food fields from dry foods to high-moisture foods, and for maintaining the quality of articles such as pharmaceuticals that can be deteriorated by oxygen.

[Brief description of the drawings]

FIG. 1 shows the relationship between the moisture content and the equilibrium relative humidity in calcined marine diatomaceous earth, unfired marine diatomaceous earth, and one type of zeolite.

Claims (6)

(57) [Claims] 1. An iron powder, an oxidation promoting substance, a filler, and
In an oxygen absorbent comprising a moisture donor composed of diatomaceous earth containing a humidity control liquid, the diatomaceous earth is obtained by baking marine diatomaceous earth at a temperature of 500 ° C.
Baked at a temperature below 1,500 ° C.
Characteristics showing a relative humidity of 55% or more when the water content is 2%
An oxygen absorbent, which is a diatomaceous earth having the following . 2. The diatomaceous earth has a pore volume of 0.1 ml / g.
As described above, the pore diameter is 500 to 10,000 nm, and the specific surface area is
0.1~100m ² / g, ion exchange capacity is 50meq
2. Oxygen absorption according to claim 1, wherein the diatomaceous earth is 100 g or less.
Agent . 3. The diatomaceous earth is obtained by firing marine diatomaceous earth.
With a temperature of 650 to 1,300 ° C
The oxygen absorbent according to claim 1 . 4. The diatomaceous earth wet extrudes marine diatomaceous earth.
After granulation, it was fired and the particle size was 0.2 to 3 mm.
The oxygen absorbent according to claim 1, which is granular diatomaceous earth . 5. An iron powder coated with an oxidation-promoting substance, and then a filler is added.
An oxygen-absorbing main agent obtained by mixing and marine diatomaceous earth are fired at a temperature of 500 ° C. or more and 1,500.
It is calcined at less than ℃ and contains 2% moisture
Diatomaceous earth with adsorption characteristics sometimes showing a relative humidity of 55% or more
Impregnated with a humidity control liquid, and
Moisture donor coated or mixed with lithium earth metal hydroxide
And a method for producing an oxygen absorbent . 6. Mixing iron powder, oxidation promoting substance and filler
Oxygen absorbing main agent and marine diatomaceous earth having a calcination temperature of 500 ° C. or more and 1,500
It is calcined at less than ℃ and contains 2% moisture
Diatomaceous earth with adsorption characteristics sometimes showing a relative humidity of 55% or more
Characterized by mixing a moisture donor impregnated with a humidity control liquid
A method for producing an oxygen absorbent .