JPS62234544A - Sheet type oxygen scavenger - Google Patents

Abstract

PURPOSE:To improve the oxygen removing rate of the title scavenger and to raise the oxygen absorbing capacity by making a mixture consisting of a fibrous substance, iron powder, water, and an electrolyte into paper, and forming a sheet material having <=50,000sec/100ml air Gurley permeability. CONSTITUTION:A fibrous substance is suspended in water wherein an electrolyte is dissolved by using a pulper, the suspension is lightly beaten with a refiner, and the iron powder is added, mixed, and suspended. The suspension is passed through a paper machine, filtered by wires, dehydrated by suction, and then pressed and dehydrated to obtain a sheet oxygen scavenger contg. 10-50wt% water. The film 11 of an oxygen-permeable resin such as vinyl chloride is coated on the surface of the sheet oxygen scavenger 10. The permeability of the sheet oxygen scavenger is controlled to <=50,000sec/100ml air Gurley permeability stipulated in JIS P-8117, or preferably to <=5,000sec/100ml air.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sheet-shaped oxygen absorber. For more details,
This invention relates to a sheet-shaped oxygen absorber characterized by forming a composition containing a fibrous substance, iron powder, water, and an electrolyte into a sheet by papermaking.

[Conventional technology]

Conventionally, oxygen scavengers have been used in which a pouch made of a breathable packaging material is filled with a chemical containing iron powder or a reducing organic substance as a main ingredient. This oxygen absorber package is hermetically sealed together with an object to be preserved, such as food, in a bag made of a non-breathable packaging material, and the food is preserved by deoxidizing the oxygen inside the bag.

[Problem that the invention seeks to solve]

Conventional oxygen absorbers in the form of sachets have the following drawbacks. In other words, (1) there is a risk of accidental ingestion as it is enclosed in a bag with food; (2) there is a limit to the size of oxygen absorbers and it is not possible to make extremely small ones, so storage space is limited. (3) If the lid of the container is small, it cannot be fixed. (4) If the size of the bag containing the substance to be preserved is small, for example, about 30 mm, it cannot be applied to the bag. (5) When fixing it to the tray, the thickness becomes too large, making it difficult to manufacture and fix the tray. (6) The bulk powder of the oxygen absorber in the bag tends to clump, so it cannot be easily sealed with air. The contact area becomes small, and in order to obtain the desired oxygen removal rate, a large excess of oxygen scavenger bulk powder is required compared to the potential oxygen absorption capacity. As a result of conducting various studies to eliminate these drawbacks, the present invention has been completed.

The present invention can be fixed to the wall surface of a package for food or other contained items, and can be used in any shape.
Another object of the present invention is to provide a sheet-like oxygen scavenger that can achieve the oxygen scavenging effect in a short time and a method for producing the same.

[Means for solving problems]

That is, in this invention, a mixture consisting of a fibrous material, iron powder, water, and an electrolyte is formed into a sheet by papermaking, and the Gurley air permeability is 50.000 sec/airlo.
The present invention provides a sheet-like oxygen absorber characterized by having an om1 or less.

In the present invention, the fibrous material serves as a carrier for iron powder, water, or electrolyte, and is used to increase the contact area between oxygen in the air and iron and to increase oxygen permeability. It is. This fibrous material is made of natural fibers or synthetic fibers, and preferably has a width of 0.2 mm or less and a length of 0.1 to 20 mm. Specifically, pulp or acrylic fiber, nylon fiber, viscose rayon, vinylon, polyvinyl chloride fiber, polyethylene fiber, polypropylene fiber, fiber made of ethylene-vinyl acetate copolymer, polyester fiber, cotton, hemp, wool,
Asbestos fibers and mixtures thereof are used, preferably pulp, polyethylene fibers, hemp, etc.

Furthermore, it is also possible to use a combination of two or more of the above fibrous substances.

Iron powder is the main component of oxygen absorbers. The type of iron powder is not particularly limited as long as it has the ability to absorb oxygen, but specifically reduced iron, atomized iron, electrolytic iron, etc. are used as the iron.

In order to mix well with fibrous substances, iron powder generally has a particle size of 0.25 mm or less, preferably 0.15 mm or less, and iron powder with a particle size of 0.05 mm or less is considered whole iron. A powder containing 50% by weight or more, preferably 70% by weight or more of the powder amount is used. If the ratio of iron powder with a particle size of 0.05 mm or less is less than 50%, the ratio of iron powder that separates from the fibrous substance increases, and the iron powder cannot be efficiently retained in the sheet-like oxygen scavenger.

The electrolyte accelerates the rate of deoxidation of the iron powder and is, for example, a sulfate, a halide, a carbonate or a hydroxide. Preferred among these salts are halides, more preferably NaC1, CaC1z, M
gC1z , FeC1□ or PeC1a. It is desirable to use these by dissolving them in water.

In the sheet-like oxygen scavenger of the present invention, the essential components are fibrous substances, iron powder, water, and electrolytes, but these include sizing agents, fillers, coloring agents, and paper strength enhancers that are usually used in paper making. A water- and oil-repellent agent, etc. can also be used in combination as appropriate.

In the sheet-shaped oxygen scavenger of the present invention, its air permeability is J
Gurley air permeability specified by IS P-8117 is 50
, 000sec/airroom1 or less, preferably 5
．． 000sec/airroom1 or less.

If the air permeability is 50,000 sec/air or more than 100 m1, the deoxidation rate will be too low to be practical.

The oxygen scavenger according to the present invention includes a predetermined amount of fibrous material, iron powder,
Suspending water and electrolytes, filtering the suspension, and further
It is dehydrated to a moisture content of 50% by weight or less, preferably 40% by weight or less, and then formed into a sheet.

The proportion of solids in the suspension is determined by fibrous substances, iron powder,
0.5 to 15% by weight based on the sum of water and electrolyte,
Preferably it is 1 to 9% by weight. The proportion of the fibrous substance in the suspension is preferably 0.01 to 12% by weight based on the sum of the fibrous substance, iron powder, water, and electrolyte, and
．． More preferably 1 to 3% by weight. In the suspension, the proportion of iron powder is 0.045 to 12% by weight, preferably 0.045 to 12% by weight, based on the sum of fibrous material, iron powder, water and electrolyte.
．． It is used in a proportion of 1 to 3% by weight. The electrolyte is usually used dissolved in water, and the amount of the electrolyte in the suspension is 0.0% based on the sum of the fibrous material, iron powder, water, and electrolyte.
05 to 30% by weight, preferably 0.1 to 10% by weight.

Note that the solid substance herein refers to a substance that does not dissolve in water and exists as a solid in the suspension.

An example of the method for producing the sheet-like oxygen scavenger of the present invention is as follows.

That is, first, a fibrous substance is suspended in water in which an electrolyte is dissolved using a pulper, and after being slightly beaten in a refiner, iron powder and other additives as necessary are added, and the mixture is thoroughly mixed and suspended. It is passed through a paper machine, filtered with a wire, dehydrated by suction, and further dehydrated in a press until the moisture content is 1.
0 to 50% by weight, preferably 20 to 40% by weight,
This sheet-like oxygen scavenger can be obtained.

Furthermore, this sheet can also be used after being dried by passing it through a dryer. The dried sheet-like oxygen absorber becomes an oxygen absorber suitable for preserving foods with high moisture content.

The sheet-like oxygen scavenger thus obtained generally contains iron powder in an amount of 10 to 5,000 parts by weight, preferably 10 to 1,000 parts by weight, per 100 parts by weight of the fibrous material. Further, the electrolyte is generally 0.01 to 900 parts by weight, preferably 0.02 parts by weight per 100 parts by weight of the fibrous material.
~100 parts by weight is contained. Further, water is contained in an amount of 0.1 to 1.200 parts by weight, preferably 1 to 400 parts by weight, per 100 parts by weight of the fibrous material.

In the present invention, the sheet-like shape has a thickness of 0.1 to 10 mm.

Preferably it means 0.1 to 5 mm.

The sheet-shaped oxygen absorber of the present invention can be used as a filtered, dehydrated, and optionally dried sheet sealed in a gas-barrier container together with food or other food to be preserved. By covering or encapsulating with another material, the sheet-shaped oxygen absorber is separated from the filling (or contents) of food, etc., and the components in this sheet-shaped oxygen absorber are prevented from transferring to the food, etc. It can also prevent contamination.

For example, as shown in FIGS. 1 and 2, the surface of a sheet-like oxygen scavenger 100 is coated with a film 11 of oxygen permeable resin. The resin used in this case is not particularly limited as long as it forms an emulsion in water or an organic solvent, but vinyl chloride, acrylic, silicone, etc.
Silicon acrylic, polyamide, polyester,
A resin composition consisting of a single resin or a copolymer of polyethylene, polypropylene, ethylene/vinyl acetate copolymer, polybutadiene, or a mixture thereof is used. Among these, practically preferred ones are:
Vinyl chloride resin, polyethylene resin, silicone resin, silicone acrylic resin, ethylene/vinyl acetate copolymer,
Polybutadiene type etc.

As a method for coating the oxygen scavenger with a film of these resins, a method may be employed in which a resin liquid in the form of an emulsion is coated by an appropriate method and then dried.

The thickness of the resin film is generally 0.1 to i', ooo
μ, preferably 1 to 500 μ. In addition, the oxygen permeation rate of the film is generally 1.000 m1/m2D.
atm or more, preferably 10.000 m1/m2D a
tm or more.

In addition, as a method for coating the surface of this sheet-like oxygen scavenger 100, an oxygen permeability of 1,000 m1/m2D atm
The above film, sheet or laminate film may also be used. Figure 3 shows a specific example of this,
Paper, non-woven fabric or microporous membrane 130 as packaging material "A"
A perforated or non-perforated plastic film 14 and a perforated plastic film 14' are laminated on both sides (one side may be used. Fig. 4 shows a specific example in this case). The sheet is folded in two, a sheet-like oxygen absorber 10 smaller than the packaging material "A'" is inserted between the two, and the peripheral edge of the packaging material "A" is then heat-sealed to complete the packaging.

In addition, as shown in Fig. 5, a sheet-shaped oxygen absorber 10
A breathable sheet 15 such as paper, nonwoven fabric, synthetic valve paper, or microporous membrane is placed on one side of the oxygen absorber 10, and a plastic film 16 is placed on the other side of the oxygen absorber 10. It may be sealed and packaged.

In both cases, the plastic film located in the seal portion is preferably a low softening point film such as polyethylene. As the nonwoven fabric, wet type, dry type, spunbond, etc. are all suitably used, but in particular, TYVEK (trade name, manufactured by nu Pont), which is a polyethylene nonwoven fabric,
Aldo (ALT, trade name, manufactured by Donami Paper Co., Ltd.) is preferable from the viewpoint of water resistance. The microporous membrane usually has extremely fine pores and has a Gurley air permeability of 0.01 to 10.0 OOsec/a.
It is a synthetic resin film that is irroom and does not allow water to pass through under normal pressure.For example, it can be used for stretching synthetic resin films such as polyethylene, polypropylene, polyfluoroethylene resin, etc., extracting foreign matter from films containing foreign matter, and removing foreign matter from films containing foreign matter. Stretching after extracting foreign matter from the film containing
A synthetic resin film obtained by hot pressing after cross-dispersing laminated nonwoven fibers, or by irradiating the film with an electron beam or the like is used. Specifically, Duraguard (trade name, manufactured by Celanese Corp.), NF Receipt (trade name, manufactured by Tokuyama Soda ■), etc. are preferably used. When laminating plastic films on both sides of paper, nonwoven fabric, or microporous membrane, the outer film is preferably polyethylene terephthalate/polyethylene, nylon/polyethylene, stretched polypropylene/polyethylene, or the like. Although the thickness of these packaging materials is appropriate, it is usually 10 mm or less, preferably 5 mm or less.

It is desirable that at least a part of the packaging material wrapping the sheet-like oxygen absorber has an oxygen permeability of 1.000 m1/m" Da atm or more, and examples thereof include the above-mentioned paper, nonwoven fabric, microporous membrane, and even , on one or both sides of which a perforated plastic film and/or a lattice-like reinforcing material such as Warif, cloth, Frenet or Soft, specifically for example Nisseki Warif (trade name, Nisseki Goju Products) sheets laminated with diamond cloth (product name, manufactured by Diatex ■), Kushinet (product name, manufactured by Kuraray), or Sofnet (product name, manufactured by Shin Nihon Sofu ■), and polyethylene, polypropylene. , ethylene-vinyl acetate copolymer, polybutadiene, polyethylene ionomer, polymethylpentene, silicone resin, and other films may also be used.

Furthermore, as shown in FIG. 6, the periphery (for example, 3 to 10 mm) of the sheet-like oxygen absorber 10 is surrounded by a low softening point resin 17, and then the above-mentioned breathable packaging material is wrapped on both sides of the sheet-like oxygen absorber 10. It is also possible to arrange and laminate a film or sheet 18,19. In this case, it is possible to suppress the contents of the sheet-like oxygen absorber 10 from seeping out, which is preferable. In this case, as the resin having a low softening point, polyethylene, polypropylene, polyethylene ionomer, ethylene vinyl acetate copolymer, etc. are used.

Furthermore, as shown in FIG. 7, a breathable laminate film containing the above-described low softening point resin layer 20 as an inner layer is used as the packaging material, and a sheet-like oxygen absorber 10 is placed between the layers.
It may also be a laminate structure in which the two are sandwiched together and the peripheral portion is heat-sealed. Note that outer layer 2 of the above laminate film
For 1, a breathable film or sheet as described above is used as appropriate. In this case, since the low softening point resin layers 20 of the laminate film are heat-sealed to each other, the contents can be prevented from seeping out as described above. Generally, methods such as thermal lamination, dry lamination, wet lamination, extrusion lamination, etc. are used as a method for press-bonding the above-mentioned laminate structure.

〔Example〕

Example 1 100 g of softwood pulp mainly composed of cellulose fibers having a length of 2 to 7 mm and a width of 0.03 to 0.05 mm,
350 g of iron powder with a particle size of 0.15 mm or less and a proportion of 80% by weight of particles with a particle size of 0.05 mm or less,
Suspended in 7.000 ml of water with 160 g of NaC,
The suspension was placed in a filter paper with a diameter of 600 mm and filtered with suction. Immediately after filtration, the oxygen scavenger with a water content of 40% by weight was compressed with a roll press and dehydrated until the water content became 30% by weight.

The sheet-like oxygen absorber thus obtained had a thickness of 1.5 mm, and 350 parts of iron powder was added to 100 parts by weight of pulp.
parts by weight, 12 parts by weight of NaC, and 195 parts by weight of water.

Example 2 The sheet-like oxygen scavenger obtained in Example 1 was
When the sample was cut into pieces with an air content II of 2.25° C. and kept sealed, the oxygen concentration became 0.1% or less in 12 hours, indicating a practically sufficient deoxidation rate.

Example 3 The sheet-like oxygen scavenger of Example 1 was further dried in a dry bomber at 85 to 95°C to a moisture content of 2.1%. The sheet-like molded product thus obtained had a thickness of 1.4 mm,
350 parts by weight of iron powder, NaC per 100 parts by weight of pulp
The composition was 12 parts by weight and 9.7 parts by weight of water.

Example 4 The sheet-like oxygen scavenger obtained in Example 3 was placed in a 9cm x 9cm
Cut into air ffi I A 5RII 100%, 2
When stored in a sealed container at 5°C, the oxygen concentration decreased to 0.0 after 15 hours.
The oxygen removal rate was 1% or less, which was sufficient for practical use.

Example 5 A sheet-like oxygen scavenger was produced in the same manner as in Examples 1 and 3, except that the fibrous material, the particle size of the iron powder, and the electrolyte were changed. This sheet-like molded product was cut into 9 cm x 9 cm and stored in a sealed state at 25° C. with an air content of 100% I A 5 RH. Table 1 shows the measurement results of the physical properties of this sheet-like oxygen scavenger.

'f31 table (■m9J 2) Gurley air permeability unit: seconds/air ffi100ml
Example 6 The sheet-like oxygen absorber obtained in Example 1 was placed in a 9 mm x 9 cm sheet.
After coating the surface with a silicone acrylic resin emulsion, it was dried at 90° C. to coat a silicone acrylic resin layer in Log/m'. The thickness of this film was 10μ. The obtained sheet-like oxygen scavenger was sealed in a gas barrier bag with 0.5 kg of Kirimochi and 0.5 I2 of air.
Stored at 5°C. The oxygen concentration inside the bag will be 0 within 12 hours.
．． It decreased to 1%. Thereafter, the rice cake was stored at 25°C for one month, but no rust was transferred to the rice cake, and the rice cake was well preserved.

Example 7 The sheet-like oxygen absorber obtained in Example 1 was placed in a 5 cm x 9 cm
A laminated film of a polyethylene terephthalate film with a thickness of 12μ and a polyethylene film with a thickness of 45μ on one side, and Tyvek, a nonwoven fabric made of polyethylene fibers, on the other side were heated under pressure at 135°C for 5 seconds. A sheet-like oxygen absorber laminated in three layers was obtained.

The sheet-like oxygen scavenger thus obtained was kept sealed at 25°C in a system with an air volume of 061, and the oxygen concentration inside was 1.
It reached 0.1% or less at 0 hours.

Example 8 Oxygen scavenging performance was measured under the same conditions as in Example 7 using a three-layer stacked oxygen scavenger obtained in the same manner as in Example 7 using various outer layer packaging materials.

The measurement results are shown in Table 'M2.

Table 2 Example 9 The sheet-like oxygen scavenger obtained in Example 1 was cut into 5 cm x 9 cm pieces on a laminate film (outer layer) of a 7 cm x 11 cm, 12 μ thick polyethylene terephthalate film and a 45 μ thick polyethylene film. A sheet-shaped oxygen absorber is placed, and the surrounding area 1 of the sheet-shaped oxygen absorber is placed.
0 mm was surrounded by ethylene-vinyl acetate copolymer resin, and a polyethylene nonwoven fabric of 7 CmXll (m) was placed on top of it and heated under pressure at 140° C. for 5 seconds to heat-seal the periphery.

The three-layer sheet-like oxygen absorber thus obtained was mixed with an air amount of 0.5
When stored at 25° C. in the closed system of No. 1, the oxygen concentration reached 0.1% in 7 hours.

〔Effect of the invention〕

The sheet-like oxygen scavenger of the present invention has the following effects.

(1) Since it can be fixed to a food container or outer bag, there is no risk of accidental ingestion. (2) It can be cut or bent to suit the space of the container and used in various forms. (3) Furthermore, it is possible to prevent stains such as rust from seeping out from the oxygen absorber.

(4) Furthermore, since the oxygen scavenger of the present invention has high air permeability, it comes into sufficient contact with oxygen, and gas can easily permeate and diffuse through the oxygen scavenger layer, resulting in a rapid oxygen removal rate. Large absorption capacity. (5) Compared to conventional oxygen absorbers in the form of sachets, it is compact in volume, small in size, and has high performance, making it a very convenient product form for practical use.

[Brief explanation of drawings]

FIGS. 1 to 7 are cross-sectional views showing various embodiments of the sheet-like oxygen scavenger according to the present invention. In the figure, 10 is a sheet-like oxygen absorber, 11 is an oxygen-permeable resin film, 13.15 is a breathable film or sheet, 14 and 14' are perforated plastic films,
16 is a plastic film, 17 is a low softening point resin, 1
8.19 represents a film or sheet, 20 represents a low softening point resin layer, and 21 represents a breathable film or sheet. Patent Application Book Mitsubishi Gas Chemical Co., Ltd. Representative Patent Attorney Sadafumi Tebori Figure 1 Figure 2

Claims (1)

[Claims] A mixture of fibrous material, iron powder, water and electrolyte is formed into a sheet by papermaking, and the Gurley air permeability is 5.
A sheet-shaped oxygen absorber characterized by an air flow rate of 0,000 sec/air 100 ml or less