JPS62244444A - Oxygen scavenger - Google Patents

Abstract

PURPOSE:To keep oxygen scavenging reaction under a high humidity condition for a long period of time, by preparing an oxygen scavenger by combining an oxidizable metal powder component with an electrolyte component and compounding a water absorbable and swellable polymer powder with the resulting composition. CONSTITUTION:An oxidizable metal powder, an electrolyte powder and a water absorbable and swellable polymer powder are mixed using a mixing apparatus for acting friction force and/or shearing force such as a friction disc mill or a Hensel mixer to obtain an oxygen scavenger. As the oxidizable metal powder, there are iron, cobalt and nickel, etc. and the particle size thereof is pref. 100-10mum. As the electrolyte component, there are alkali metal halide and alkaline earth metal halide and the particle size thereof is pref. 100-10mum. As the water absorbable and swellable polymer powder, there are carboxy methyl cellulose and a starch/polyacrylonitrile hydrolysate, etc.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to an oxygen scavenger.

[Prior art]

Conventionally, various oxygen scavengers based on powders of oxidizable metals such as iron powder, copper, and zinc have been proposed. agent is known (Japanese Unexamined Patent Publication No. 17633/1983)
. The deoxidizing reaction of such oxygen absorbers is suppressed and stable in dry air or low humidity air, but in high humidity air, they absorb moisture in the air and perform the deoxidizing reaction. Start and absorb oxygen from the air. However, although such oxygen scavengers exhibit a good deoxidation reaction under high humidity, due to the action of the electrolyte used in them, they absorb excess moisture in a relatively short period of time, causing the deoxidation reaction to deteriorate. It has been found that there are disadvantages in that the deoxidizing reaction is significantly inhibited or the deoxidizing reaction is stopped. For example, the above-mentioned oxygen absorber (a mixture of 100 parts by weight of iron powder and 10 parts by weight of common salt filled in a breathable pouch) may be placed in a plastic bag along with foods with high water activity (for example, cut rice cakes, etc.). When sealed, the relative humidity inside the bag will be 100%, so the oxygen absorber will smoothly start the deoxidizing reaction, and the oxygen concentration inside the plastic bag will drop to 1% or less within 12 hours. However, after one month or two has passed, the oxygen scavenger absorbs excess moisture relative to the oxygen scavenging reaction, and as a result, the oxygen scavenging reaction substantially stops, and the oxygen scavenger stops functioning. substantially lost. This tendency is particularly noticeable when sachets filled with oxygen scavengers come into contact with foods with high water activity. On the other hand, it may take more than a month for a product to reach the consumer from its manufacture, so the oxygen scavenger applied to it is required to maintain its oxygen scavenging function sufficiently during distribution. Ru.

〔the purpose〕

The present invention aims to overcome the above-mentioned drawbacks of conventional oxygen scavengers and to provide an oxygen scavenger that can continue its oxygen scavenging reaction over a long period of time under high humidity.

〔composition〕

According to the present invention, in an oxygen scavenger that exhibits a deoxidizing reaction under high humidity and is made of a combination of an oxidizable metal powder component and an electrolyte component, the oxygen scavenger contains a water-absorbing swelling polymer powder. An oxygen scavenger is provided.

In the present invention, in order to overcome the above-mentioned drawbacks of oxygen scavengers that are in the form of a substantially dry mixture consisting of a combination of metal powder and electrolyte components and exhibit oxygen scavenging reactions under high humidity, we have developed It is characterized by adding swellable polymer powder. In this case, the water-absorbing swelling polymer absorbs excess water in the deoxidation reaction caused by the electrolyte, maintains the moisture in the oxygen scavenger system within the required range, and smoothly maintains the moisture content for long periods of time even under high humidity. Shows the action of advancing the deoxidizing reaction.

The metal powder used in the present invention may be any oxidizable metal powder, and various conventionally known metal powders may be used, such as iron, cobalt, nickel, manganese, zinc, copper, etc. In addition to powders of transition metals such as, alloys and carbides thereof, iron powders are generally used. In this case, the iron powder does not need to be pure iron, but only needs to have iron as its main component. Good too. Further, this iron powder may be manufactured by various methods, such as reduced powder, electrolytic powder, spray powder, crushed powder, etc. The particle size of the oxidizable metal powder is generally 1.50 μm or less, preferably 10 μm or less.
It is in the range of 0 to 10 μm.

As the electrolyte used in the present invention, various organic or inorganic acid salts are used, such as, for example,
Alkali metal halides such as NaCQ, KCfl, NaBr, and Br, MgCu2, CaCn2
In addition to alkaline earth metal halides such as CaBr2MgBr2 and BaBr2, AgCQ2, ZnCQ
2, AQCQ3, SnCQ 2゜MnCQ 2, FeC
l13. CaCO2, NxCQ2, CuCQ, Z
Various metal halides such as nBr2, SnBr2, CuBr, FeBr2, as well as Na2SO4, K2S0
．． , CaSO4, MgSO4, Al12(SO4)aN
j, SO-, various sulfates such as FeSO4, NH4CQ
, NH4Br, various ammonium salts such as (Ni1.)2SO4, sodium perchlorate, calcium perchlorate, sodium periodate, sodium chlorate, potassium chlorate, calcium chlorate, sodium bromate, calcium bromate, iodine sodium acid, calcium bromate, sodium iodate, potassium iodate, sodium chlorite, potassium chlorite, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, sodium hypobromite, etc. Examples include halogen-containing oxyacid salts. The particle size of the electrolyte powder is generally 1.50 μm or less, preferably in the range of 100 to 10 μm. Such electrolyte powder has a content of 0.0 parts by weight per 100 parts by weight of metal acid.
It is used in an amount of 1 to 10 parts by weight, preferably 0.1 to 2% by weight.

In the present invention, in order to obtain an oxygen scavenger that starts the oxygen scavenging reaction quickly, the electrolyte should be one that has deliquescent properties such as calcium chloride, magnesium chloride, iron chloride, aluminum chloride, crude common salt, etc. The use of electrolytes containing is preferred.

The water-absorbing and swelling polymer particles used in the present invention refer to polymer particles that have the property of absorbing water and swelling, and include ionic salts such as carboxylates, sulfonates, phosphates, or ammonium salts. It has a group in the polymer. Such polymers are conventionally known, and for example, when classified by polymer base material, there are carboxymethyl cellulose, starch/polyacrylonitrile hydrolyzate, and starch/polyacrylonitrile hydrolyzate.
Polyacrylate crosslinked product system, saponified vinyl acetate/methyl acrylate copolymer system, polyacrylonitrile hydrolyzate system, polyacrylate crosslinked product system, vinyl alcohol/acrylate copolymer system, ethylene/methacrylate There are acid-acid copolymer types, etc. These water-absorbing and swelling polymer particles absorb water at least 200 times their own weight, and in the case of highly water-absorbent particles, about 1000 times their own weight. In the present invention, generally 20 times or more of its own weight, preferably 5
Any material that exhibits a water absorbency of 0 times 0'' can be used.

The water-absorbing and swelling polymer particles used in the present invention may be in the form of fine powder, and generally have a particle size of about 100 μm to 1 mm. The proportion of water-absorbing and swelling polymer particles to be used is in the range of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the oxidizable metal component. If the proportion used is too high, the reactivity of the oxygen scavenger obtained tends to deteriorate, and if the proportion is too small, effective moisture absorption cannot be carried out. When an oxygen absorber is brought into contact with foods with high water activity, moisture permeates through the air-permeable bag that encloses the oxygen absorber. The deoxidizing reaction is not inhibited by the moisture that comes in. According to the present inventors, in the case of an oxygen scavenger made of a mixture of metal powder and electrolyte, if more than 20% of the weight of water is mixed into the oxygen scavenger, it can no longer be used as an oxygen scavenger. However, in the oxygen scavenger of the present invention, due to the action of the small absorbing and swelling polymer particles added to it, the use of 20
Even if more than 30% of water is mixed in, its deoxidizing reactivity is not impaired.

In order to produce the oxygen scavenger of the present invention, the above-described oxidizable metal powder, electrolyte powder, and water-absorbing swelling polymer powder may be mixed. In this case, as the mixer, in order to bring each component into close contact with each other, it is preferable to use a mixing device that applies a force and/or shear force, such as a Masatsu disk mill or a Hensel mixer.

Various changes are possible in the oxygen scavenger of the present invention,
It is also effective to coat the surface of the oxidizable metal powder with the electrolyte in advance. Such metal powder whose surface is coated with electrolyte can be produced by mixing an aqueous electrolyte solution and metal powder and drying it, or by mixing an aqueous solution of an acidic substance such as hydrochloric acid, sulfuric acid, or an organic acid with metal powder. There is a method of mixing, reacting an acidic substance on the surface of the metal powder, and then drying. Such metal powder whose surface is coated with electrolyte is similar to the above-mentioned mixture of metal powder and electrolyte,
Reacts with atmospheric oxygen under high humidity. Further, if such a metal powder whose surface is coated with an electrolyte is kept under high humidity for a long time, it will absorb more moisture than is suitable for the deoxidation reaction, and the deoxidation reaction will be inhibited. The principles of the present invention can also be applied to such an oxygen scavenger made of metal powder whose surface is coated with an electrolyte.

In this case, the proportion of the electrolyte component coated on the surface is about 0.01 to 10 parts by weight, preferably about 0.1 to 1 part by weight, based on 100 parts by weight of the metal powder.

In addition, in the oxygen scavenger of the present invention, if necessary, an appropriate amount of porous material powder is added, for example, about 0.05 to 5 parts by weight, preferably about 0.01 to 2 parts by weight, per 100 parts by weight of metal powder. can be added. In this case, the particle size of the porous material powder is generally 150 μm or less, preferably 1
The porous material powder preferably supports an electrolyte. This electrolyte support is carried out by mixing an electrolyte aqueous solution and porous material powder, and drying the mixture to a moisture content of about 15% or less. Various organic or inorganic materials are used as the porous material, such as oily carbon, activated carbon, coal powder, coke, zeolite, perlite, vermiculite, loess, diatomaceous earth, bentonite, kaolin,
Examples include sepiolyte 1-1 clay, silica, alumina, magnesia, silica/alumina, and the like.

According to a preferred embodiment of the present invention, the particle size is 150 μm or less,
Preferably, per 100 parts by weight of metal powder with a particle size of 100 μm or less, 0.05 to 5 parts of electrolyte powder with a particle size of 11007z or less, preferably 50 μm or less, preferably 0.1 to 4 parts by weight.
Part by weight and particle size 500 μm or less, preferably 200 μm
An oxygen scavenger consisting of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight of the following water-absorbing swelling polymer powder is provided.

According to another preferred embodiment of the present invention, there is provided an oxygen scavenger of the present invention described above, in which a chlorate is used as at least a portion of the electrolyte powder. Such an oxygen absorber absorbs moisture under high humidity and starts a deoxidizing reaction, and also generates a small amount of sterilizing chlorine-based gas from the added chlorate. for example,
Sodium chlorite (NthCβ02
), chlorine dioxide gas (cQO7) is generated. Furthermore, when a sulfite such as sodium hydrogen sulfite or monohelium sulfite is used in place of the chlorate, sulfur dioxide gas is generated. Therefore, when such an oxygen absorber is sealed together with food in a plastic bag, the inside of the bag is deoxidized and the surface of the food is sterilized at the same time.

The generation of chlorine-based gas and sulfur dioxide gas is caused by acidic substances such as sulfates such as iron chloride, calcium chloride, iron sulfate, and calcium sulfate, solid organic acids or their salts, sulfuric acid, and organic acids supported. This can be promoted by adding porous material powder or the like. In such an oxygen scavenger, the amount of chlorate or sulfite used is 1
The amount is usually 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight.

In the present invention, generating chlorine-based gas or sulfur dioxide gas by absorbing moisture from chlorate or sulfite in the presence of metal powder means that excessive chlorine-based gas or sulfur dioxide gas is generated due to the action of the metal powder. This is very advantageous because trace amounts of chlorine-based gas and sulfur dioxide gas are generated stably over a long period of time.

The oxygen scavenger of the present invention consists of a mixture in a substantially dry state and is stable in dry air or low humidity air, but in high humidity air it absorbs moisture in the air and undergoes a deoxidizing reaction. Start smoothly. The oxygen scavenger of the present invention has a water content of 5% by weight.
Thereafter, the oxygen absorber is filled in a dry state, preferably at a concentration of 1% by weight or less, into a breathable pouch, and the oxygen scavenger-filled pouch is sealed and stored in a non-breathable plastic bag.

〔effect〕

The oxygen scavenger of the present invention has the above-mentioned structure, and by mixing water-absorbing and swelling polymer particles with a metal powder containing an electrolyte, the surface of the metal powder absorbs excess water from the electrolyte, causing the surface of the metal powder to absorb the water. is prevented from being wetted by
The deoxidizing reaction can be continued for a long period of time in high humidity air.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (1) Get rid of N! Production of base material C1) (a) Metal powder [F]: As metal powder, the amount passing through 150 mesh is 65% by weight,
Iron powder having an amount of 50% by weight passing through 200 meshes was used.

(b) Water-absorbing swelling polymer powder [P]: Commercially available vinyl alcohol/sodium acrylate copolymer beads (particle size approximately 0.5 mm, manufactured by Sumikagaku Co., Ltd., "Sumikagel") were used. (c) Electrolyte powder [E]: Commercially available salt (4.5% by weight passing through 50 meshes, 80.5% by weight passing through 28 meshes) was dried and pulverized to a particle size of 350 meshes or less.

(d) 100 parts by weight of the metal powder [F], the water = 12-31 parts by weight of the absorption-swelling polymer (+), and the electrolyte powder [E]
Add 0.6 parts by weight and mix uniformly in a mortar to prepare the oxygen absorber [
1] was manufactured.

(E) For comparison, only 0.6 parts by weight of the electrolyte powder (IE) was added to 1.00 parts by weight of the metal powder (F), mixed uniformly in a mortar, and oxygen scavenger (n) was manufactured.

(2) Reactivity test of oxygen scavenger 2.7 g of each of the above-obtained aS agents (1) and [old] were placed in a sachet [overlaid with breathable plastic film (product name: Typec) and sealed on three sides. Dimensions 5αX5an
sachet] was filled through its opening, and the opening was sealed.

Place this oxygen absorber filling bag in a container with a space of about 500cc,
Furthermore, absorbent cotton soaked with 5 cc of water was placed in contact with the oxygen absorber-filled sachet, fixed with cellophane tape, and sealed, and the oxygen concentration in the sealed space was measured at predetermined time intervals. We measured the decrease in

The results are shown in Table-1. After continuing this reactivity test (first reactivity test) for 15 days, we removed the oxygen absorber filling bag from the container, opened the lower end of the filling bag, and observed the inside. (Water accumulated inside the oxygen absorber [rl] bag, and the entire bag became soaked and could no longer be used as an oxygen absorber. On the other hand, with the product of the present invention (oxygen scavenger [I], it was confirmed that the added polymer particles [P] absorbed moisture and swelled, and that the oxygen scavenger [I] had good deoxidation properties. It was confirmed that the oxygen absorber (1) exhibits an oxygen reaction.Table 2 shows the oxygen absorber (1).
After this was left in the air for 2 hours, the same reactivity test as above (second reactivity test) was repeated, and the results are shown below.

11 (First reactivity test) Table 2 (Second reactivity test) From the above, the oxygen absorber of the present invention exhibits a smooth deoxidation reaction over a long period of time even in high moisture environments. I understand that.

Example 2 Electrolyte powder [E] to 100 parts by weight of metal powder (F)
0.6 parts by weight and water-absorbing swelling polymer (P) 0.1-1
0 parts by weight and 0.5 parts by weight of activated carbon fine powder were added and mixed uniformly in a mortar to obtain a de-Ming agent.

This oxygen scavenger was filled into the sachet shown in Example 1 so that the metal powder content was 2.5 g. Place this oxygen absorber filled pouch in a container with a space of about 500cc and add 5cc of water.
Place the absorbent cotton soaked in the oxygen absorber in a separate manner so that it does not come into contact with the oxygen absorber-filled bag, seal the entire bag, and measure the oxygen concentration in the sealed space at two predetermined time intervals to measure the decrease in the oxygen concentration. did. The results are shown in Table-3. From the results in Table 3, it can be seen that when the amount of water-absorbing swelling particles added is too large, the reactivity of the oxygen scavenger is impaired.

Table 3 Example 3 12g of common salt and sulfuric acid (concentration 95%) per 100cc of water
After adding 3 cc of this aqueous solution and uniformly mixing 25 cc of this aqueous solution with 100 g of zeolite powder having a particle size of about 0.7 mm, the resulting mixture was heated and dried to obtain a porous material coarse powder [T-]. made. Next, this coarse powder [T-1
] is finely pulverized to produce a fine powder with a particle size of 150 mesh or less [T~
2] was obtained.

Next, 0.6 parts by weight of the electrolyte powder (E) and 0.6 parts by weight of sodium chlorite were added to 100 parts by weight of the metal powder (F).
2 parts by weight, 1 part by weight of polymer powder [P], and 0.5 parts by weight of the porous material fine powder (T-2) were added and mixed uniformly in a mortar to obtain an oxygen absorber. When I put 3g of this oxygen scavenger into a small bag and added ice water to this bag, the polymer powder [
The water was absorbed by the action of P], and free water did not accumulate at the bottom of the sachet. Furthermore, due to the addition of water, the odor of chlorine dioxide gas liberated from chlorite was observed, and the generation of chlorine dioxide was confirmed.

For comparison, in the case of an oxygen absorber obtained in the same manner except that polymer powder CP) was not added, the same test as above was conducted, and it was confirmed that free water accumulated at the bottom of the sachet. Ta.

Example 4 An oxygen absorber was prepared in the same manner as in Example 3 except that sodium hydrogen sulfite (NalISO3) was used instead of chlorite, and water was added to it in the same manner. The color of the p)l test paper impregnated with the water retained in the sample changed to a color in the acidic range, and the generation of sulfur dioxide gas was confirmed. Furthermore, no free water accumulation was observed at the bottom of the sachet.

Example 5 To 100 parts by weight of the metal powder [F], 0.6 parts by weight of the electrolyte powder [E], 1 part by weight of polymer powder [P], and 0.2 parts by weight of sodium chlorite were added, Mixed evenly in a mortar. In the case of this mixture as well, generation of chlorine dioxide was confirmed by the addition of water in a similar manner. Furthermore, in this experiment, when sodium hydrogen sulfite was used instead of sodium chlorite, generation of sulfur dioxide gas was confirmed. In addition, in these experiments as well, no accumulation of free water was observed at the bottom of the sachet.

Example 6 In Example 3, ferrous sulfate/ferrous sulfate was used instead of 3 cc of sulfuric acid.
An oxygen absorber was obtained in the same manner except that 71 (2015 g) and 5 g of citric acid were used. 3 g of this oxygen absorber was placed in a sachet,
When one drop of ammonia water was added to this bag and the odor inside the bag was examined, ferrous sulfate reacted with ammonia and no ammonia odor was detected.

Claims (1)

[Claims] (1) In an oxygen scavenger that exhibits an oxygen scavenging reaction under high humidity and is made of a combination of an oxidizable metal powder component and an electrolyte component,
An oxygen absorber characterized in that the oxygen absorber contains a water-absorbing swelling polymer powder.