JPH04210232A - Sheet-shaped deoxidizer - Google Patents

Abstract

PURPOSE:To obtain an extremely thin high-performance deoxidizer capable of being shaped in conformity to usage by dispersing and holding an oxidizable metallic powder in a sheet-shaped support in which fibers are irregularly laminated and impregnating the support with an aq. electrolyte soln. CONSTITUTION:A metallic powder 4 of iron, aluminum, etc., is dispersed and held in a sheet-shaped support 3, in which fibers 1 of natural pulp, etc., are irregularly laminated and many voids 2 are formed, to obtain a structure. An aq. soln. of the inorg. electrolyte such as sodium chloride and potassium chloride is sprayed on the structure to impregnate the structure. The metallic powder is uniformly dispersed and held in the sheet-shaped deoxidizer without the powder being separated, the deoxidizer can be thinned in optional size and shape, and the performance is enhanced.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a sheet-like oxygen absorber, and more particularly to a thin sheet in which an oxygen absorbing composition is held on a support in which fibers are irregularly laminated. The present invention relates to oxygen scavengers.

[Prior art, 1. Conventionally, as an oxygen scavenger, a powdery composition containing as a main ingredient oxidizable metal powder such as iron powder that is highly reactive with oxygen, reducing organic matter, etc. has been used as an oxygen scavenger. Chimeka has been used stored in a bag.

When this oxygen absorber is sealed and stored in a non-ventilated container or bag together with food or other preserved items, the oxygen in the air inside the container or bag reacts with the oxygen absorber and is removed. Food can be stored for a long time without deterioration.

[Problem to be solved by the invention]

However, since conventional oxygen scavengers consist of powder and granules stored in bags, they have the following problems.

■Because they are stored together with food in the storage container, there is a risk that children may accidentally eat them.

■There are limits to how small the size and thickness can be made, and small containers and trays are difficult to fix or store in narrow spaces.

Depending on the type of food, there are disadvantages such as unevenness of the powder within the bag, local heat generation due to clumping, and other problems such as deterioration of the quality of the food.

Second, it is thin and the deoxidizing composition is not unevenly distributed, and
There is a demand for an oxygen scavenger that can be obtained in any size and shape, that can be easily fixed to the lid or inner wall of a container, and that has excellent oxygen scavenging performance.

5. Means and action for solving the problems] The present inventors have solved these problems, and have created a thin, homogeneous overall structure without movement, agglomeration, or detachment of the deoxidizing composition.
As a result of intensive research to obtain an oxygen scavenger with excellent oxygen absorption performance, we discovered that by using a sheet-like support with irregularly laminated fibers and many fine voids, metal powder can be separated. The present invention was achieved based on the discovery that the particles can be uniformly dispersed and retained without any problems.

That is, the present invention impregnates an aqueous inorganic electrolyte solution into a structure in which oxidizable metal powder is dispersed and held in a sheet-like support in which fibers are laminated irregularly and a large number of voids are formed inside. This is a sheet-shaped oxygen absorber characterized by the following.

In the present invention, a sheet-like support in which fibers are randomly laminated and has a large number of voids is used.

The material for the support may be either organic or inorganic fibers, and organic fibers are usually used. Examples of these materials include pulp, hiscose rayon, cotton, linen,
Natural fibers such as wool, vinylon, polyvinyl chloride, polyethylene, polypropylene, polyethylene, nylon,
Examples include paper or nonwoven fabrics made of synthetic fibers such as acrylic and ethylene-vinyl acetate copolymers.

Among these, nonwoven fabrics produced by dry or wet papermaking using natural valves with a high porosity and a high water retention ratio are preferred.

For example, Kinocloth (Honshu Paper ■) is a dry nonwoven fabric.
, BOL T (American Can Co.), and wet-type nonwoven fabrics such as AR-27M (Mitsubishi Paper Mills @).
V■V A (5cott company), Z E
E (Crown Zellerbach)
etc. are suitable.

The thickness of the support is usually 0.2 to 5.0 mm, preferably 0.5 to 4.0 mm, and the weight per m2 is about 21] to 200 g, preferably 30 to 170 g. be.

The oxidizable metal powder held on the support is iron powder, aluminum powder, etc., or iron powder is usually used.

Iron powder is the main component of the oxygen scavenger, and there are no particular restrictions on its type as long as it absorbs oxygen through a reaction, but examples include reduced iron powder, mist-blown iron powder, and electrolytic iron powder. is usually 60 mesh or less on average, and preferably contains 50% or more of 100 mesh or less.

In the present invention, a structure holding oxidizable metal powder is impregnated with an inorganic electrolyte aqueous solution.

The inorganic electrolyte accelerates the oxidation reaction of metal powder, and is usually a sulfate, carbonate, chloride, hydroxide, or the like of an alkali metal, alkaline earth metal, or heavy metal.

Among these, chlorides are preferred, such as NaCl,
Examples include KCI, CaCl2.51gC12, FeCl□ and FeCl3.

In the present invention, for the purpose of promoting oxidation and adjusting water retention, it is preferable to use a solution in which activated carbon is further added and suspended in the non-electrolyte aqueous solution. Activated carbon includes, for example, charcoal, wood powder charcoal, charcoal, peat, and lignite.

If desired, in addition to activated carbon, zeolite, diatomaceous earth, perlite, vermiculite, water-absorbing resin, and the like may be mixed as a water-retaining agent.

Next, a method for manufacturing the sheet-like heating element of the present invention will be explained.

First, metal powder such as iron powder is uniformly scattered on a sheet-like support made of irregularly laminated fibers of the above-mentioned material, and then when vibration is applied, the metal powder gradually fills the voids inside the support. It enters the body and is held by the support. The amount of metal powder is usually 0.1 to 30 g, preferably 3 to 20 g per 1 g of support, and is adjusted to a predetermined amount by adjusting the amount of spraying, the strength of vibration, etc. Through this operation, the metal powder is dispersed and held within the voids of the support, resulting in a sheet-like structure in which the metal powder and fibers are integrated.

Next, this structure is impregnated with an inorganic electrolyte aqueous solution to form a sheet-like oxygen scavenger.

The proportion of the inorganic electrolyte aqueous solution is usually 0.05 to 0.5 g, preferably 0.0 to 1 g of metal powder held in the structure.
．． It is 1 to 0.4 g. In addition, the ratio of water and electrolyte in the electrolyte aqueous solution is usually 1:0 by weight, 002~
The ratio is about 0.20, preferably 1:0.005 to 0.15.

In addition, when impregnating an electrolyte aqueous solution in which activated carbon is suspended, the ratio is usually 0.05 to 0.60 g, preferably 0.1 to 0.5 g per 1 g of metal powder in the structure.
The ratio of water: activated carbon: inorganic electrolyte in an electrolyte aqueous solution in which activated carbon is suspended is usually 1 +
0.01-0.30: 0.002-0.20, preferably 1:0.02-0.20: 0.005-0.
It is about 15.

Impregnation methods include uniformly impregnating a sheet-like structure with a predetermined amount of an aqueous electrolyte solution;
(2) There is a method of applying and impregnating the structure by passing it between rolls to which an aqueous electrolyte solution has been attached, and the amount of impregnation can be adjusted by adjusting the pressure between the rolls.

The sheet-like oxygen absorber obtained in this way is used by cutting one or more sheets into an appropriate size, but depending on the properties of the food to be preserved, etc. It is further dried to adjust the moisture content before use.

The sheet-like oxygen scavenger thus obtained can be used as it is by being placed in a gas barrier container, bag, etc. together with food or other food to be preserved.
Form a breathable film on the surface, cover it with a breathable film, or store it in a breathable flat bag to prevent the oxygen absorbing composition from migrating and contaminating food. It is used in a form that can prevent it from happening.

In order to form a breathable film, it is preferable to use a synthetic resin that forms an emulsion in water or an organic solvent. Examples of the material include vinyl chloride, acrylic, silicone, silicone/acrylic, and polyamide. , polyester-based, polyethylene-based, polypropylene-based, ethylene-vinyl acetate copolymer, polybutadiene-based, and other synthetic resins alone, mixtures, or copolymers can be used.

As a method for forming an air-permeable film using these resins, there is a method in which an emulsion resin liquid is applied or sprayed onto the surface of a sheet-like oxygen scavenger and then dried.

The thickness of the coating is generally 1 to 1000μ, preferably 5
~500μ, and the oxygen permeation rate of the film is usually ION 1/m2・D-atm or higher,
Preferably it is 5ON1/m2·D-atm or more.

In addition, when using a sheet oxygen absorber covered with a breathable film or sheet, or stored in a breathable bag, these packaging materials have an oxygen permeation rate of INη.
A film, sheet or laminated sheet having a resistance of /mZ/p-atm or higher is used. As materials for the packaging material, natural fibers, nonwoven fabrics made of synthetic fibers, woven fabrics, paper, various synthetic resin films, and composite sheets thereof are used.

natural fibers such as cotton, linen, silk, wool and rayon;
Non-woven fabrics and woven fabrics made of synthetic fibers such as nylon, polyethylene, polypropylene, polyacrylic and polyvinyl chloride; synthetic resin films such as polyethylene, polypropylene, nylon, polyester and polyvinyl chloride; It is also possible to use a breathable film in which pores are formed by needles, lasers, electrical discharge machining, etc. to provide breathability, or a microporous film that inherently has a large number of micropores of 20 μm or less.

Among these, composite sheets of non-woven fabric and synthetic resin film with breathability added to them, micro-porous films alone or with some of the micro-pores restricted in air with paint, heat fusion, etc., micro-porous films with non-woven fabrics or It is preferable to use one in which perforated synthetic resin films are laminated.

The bag or covering material may be composed entirely of such a breathable film or sheet, or may be partially composed of a non-breathable film or sheet, such as on one side. Good too. As the non-air permeable film or sheet, the above-mentioned films made of various synthetic resins, composite sheets of these films and nonwoven fabrics, aluminum foil, or aluminum laminated sheets laminated with synthetic resin films can be used.

Further, if desired, an adhesive layer may be partially provided on the outer surface of the sheet-like oxygen scavenger for the purpose of being attached to the inner wall of a container for storing objects to be stored.

Next, the sheet-like heating element of the present invention will be specifically explained with reference to the drawings.

Figure 1 is a cross-sectional view of a sheet-like heating element, and Figures 2 to 4 are a sheet-like heating element covered with the sheet-like oxygen scavenger shown in Figure 1 or an air-permeable coating or housed in a bag. FIG. 3 is a cross-sectional view of a sheet-like oxygen scavenger with different embodiments.

In FIG. 1, an inorganic electrolyte aqueous solution is added to a sheet-like structure in which fibers 1 are laminated irregularly and metal powder 4 is dispersed and retained in the voids 2 of a sheet-like support 3 in which numerous voids 2 are formed. By spraying and impregnating the inside of the structure with (not shown), the metal powder 4 and the inorganic electrolyte aqueous solution are mixed with each other and integrated with the support 3 to form the sheet-like oxygen scavenger i. It has become.

FIG. 2 shows a sheet-like oxygen scavenger i as shown in FIG. 1, which is coated by overlapping microporous films 6 on both sides and adhering the films to each other at their peripheral edges 7.

FIG. 3 shows a case where a breathable sheet in which a microporous film 6 and a nonwoven fabric 8 are laminated is used on one side, and a non-breathable aluminum laminate sheet in which a low softening point resin 10 is laminated on aluminum foil 9 is used on the other side. , microporous film 6 and low drying 1 hit point resin 1
Inside the bag, the 0 side is the inner surface and the peripheral edge 7 is glued,
It houses a sheet-shaped oxygen absorber as shown in Figure 1.

Further, FIG. 4 shows a sheet-like oxygen scavenger i as shown in FIG. 1 with an air-permeable coating 11 made of a synthetic resin emulsion formed on the surface thereof.

The various forms of oxygen scavenger thus obtained are further sealed and stored in an outer bag made of non-breathable film or the like until use.

〔Effect of the invention〕

In the sheet-like oxygen scavenger of the present invention, the oxygen scavenging composition is uniformly dispersed on the support and firmly held, so there is no deviation or deformation due to detachment or movement of the composition, and the shape of the food storage container is eliminated. It can be used in various forms by cutting or bending it into any size or shape depending on the space available. In addition, compared to conventional oxygen scavengers that contain powdered compositions in sachets, they are extremely thin, do not cause local heat generation due to agglomeration, and have a high oxygen scavenging rate, making them compact and high-performance. It can be made into a product form and has a wide range of uses.

〔Example〕

Example 1 A paper-like nonwoven fabric (Kinocloth, Honshu Paper ■) in which pulp fibers are laminated irregularly as a support, with a basis weight of 70 g/rn''
, thickness 1,2 mm, tensile strength; Dry 3.5Kg/1
00mm, Wet 2.0Kg/100mm, Elongation;
Dry 1g%, 1lleel thick was used.

A particle size of 300 m was placed on a support cut into 201 x 20 marks (length).
32.8g reduced iron powder containing 80% or more of esh or less
was sprinkled uniformly and vibrated to hold the iron powder on the support to form a sheet-like structure.

A sheet-like oxygen absorber was obtained by spraying 9.2 g of a 3 wt % aqueous solution of common salt in which activated carbon was suspended at 13 W % in water on this structure, and pressing with a roller to uniformly impregnate the structure. This material was cut to 5 cm x 5 cm, and a composite sheet of nonwoven fabric and microporous film with an oxygen permeability of 70
It was stored in the inner bag of a 7ON l/m" D ATM.

This sheet-like oxygen absorber was sealed in a Tetra bag with 1.2 parts of air, and the change in oxygen concentration was measured at a room temperature of 20°C. It was 8 vol. 1% in 4 hours and 0.0 vol. in 9.5 hours. It was 1 vol % or less, and had a practically sufficient oxygen removing ability.

Example 2 The same kind of paper-like nonwoven fabric used in Example 1, 10 cm
Reduced iron powder 7.
6 g was dispersed and held in the same manner as in Example 1 to obtain a sheet-like structure. A 1 wt% aqueous solution of common salt 2.
8 g was sprayed and impregnated in the same manner as in Example 1 to obtain a sheet-like oxygen absorber.

This is a composite sheet of non-woven fabric and microporous film on one side with an oxygen permeability of 707 ON (j/m2・D・a
tm sheet and an inner bag using a non-breathable sheet on one side.

This oxygen absorber was sealed in a Tetra bag with air 11, and the change in oxygen concentration was measured at a room temperature of 20°C. It was found that 6 VOI in 4 hours was 0.1 VO1% in 8 hours.
Example 3 AR-27M (Mitsubishi Paper Industries ■, basis weight 155 g/m2) was used as the nonwoven fabric for the support. Ild 1. Ocm
>3.4 g of reduced iron powder of the same type as used in Example 1 was uniformly sprinkled on a 10 cm wide support and vibrated to hold the iron powder on the support to form a sheet-like structure.

This structure was coated with a 3 wt % aqueous solution of common salt in which activated carbon was suspended at 7.2 wt % in water. A sheet-shaped oxygen absorber was obtained by spraying Og and pressing with a roller to uniformly impregnate it.

This material was cut to 8 cm x 8 cm, and one side was covered with a composite sheet of nonwoven fabric and microporous film with an oxygen permeability of 7.
07ON 12/m”・I)-atm seat,
It was stored in an inner bag with a non-breathable sheet on the other side.

This sheet-like oxygen absorber was sealed in a Tetra bag with air at 1°C, and changes in oxygen concentration were measured at room temperature of 20°C. The results were 8.8vo1% and 10.2% over 4 hours.
The sail was reduced to 1vo1% or less in hours, and had a practically sufficient oxygen removal ability.

Example 4 A paper-like nonwoven fabric (kinocloth) in which pulp fibers are irregularly laminated as a support, basis weight 40 g/m2, thickness 1.0 mm, tensile strength: Dryl, 6 Kg/100 mm, W
et 0.8Kg/100 am, elongation; Dry 1
g%, Wet, 28% was used.

Vertical 20σ×Il! Example 1 was applied to a support cut to 20 cm.
10.8 g of reduced iron powder of the same type used in was uniformly sprinkled and vibrated to hold the iron powder on the support to form a sheet-like structure.

A sheet-like oxygen absorber was obtained by spraying 1.3 g of a 3 wt % aqueous solution of common salt, in which activated carbon was suspended at 6.5 wt % in water, on this structure and pressing with a roller to uniformly impregnate the structure.

Cut this into 7cm x 7cm pieces and stack them on top of each other.
It was housed in an inner bag of a composite sheet of nonwoven fabric and microporous film with an oxygen permeability of 707 ON 4 /m 2 ·D-atm.

This sheet-shaped oxygen absorber was sealed in a Tetra bag with air at 1°C, and the change in oxygen concentration was measured at room temperature of 20°C. It was found to be 10.5 vol% in 4 hours and 0.1 vol in 12 hours. % or less, and had a practically sufficient oxygen removing ability.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a sheet-like heating element, and FIGS. 2 to 4 are cross-sectional views of different embodiments in which the sheet-like oxygen absorber of FIG. 1 is covered with a breathable film or stored in a bag. . The drawing numbers are as follows. 1. Fiber 2. Voids 3. Support 4, metal powder
Sheet-like oxygen scavenger 6, microporous film 71 peripheral portion 8, nonwoven fabric 9. Aluminum foil 10, low softening point resin 11. Coating patent applicant Nippon Bionics Co., Ltd. ff← Agent
Patent attorney Sadafumi Kobori Drawing pole / open spear Z Figure 4 Concave procedure amendment (5 types) % formula % 1. Indication of the case 1990 Patent Application No. 330161 2 Name of the invention Sheet-shaped oxygen absorber Representative Ryo Yamazaki - Drawing 7/ ,;,y'

Claims (2)

[Claims] (1) A structure in which oxidizable metal powder is dispersed and held in a sheet-like support in which fibers are laminated irregularly and a large number of voids are formed inside, and the structure is impregnated with an inorganic electrolyte aqueous solution. A sheet-shaped oxygen absorber featuring: (2) The sheet-like oxygen scavenger according to claim 1, wherein the inorganic electrolyte aqueous solution contains activated carbon in a suspended state.