JPH0615168A - Oxygen absorbent - Google Patents

Abstract

PURPOSE:To provide an oxygen absorgent having excellent water resistance and bleeding resistance and fast oxygen absorption rate. CONSTITUTION:This oxygen absorbent consists of an deoxidizing agent packed in a packaging material. The packaging material is obtd. by laminating a plastic film outer material, intermediate material having air permeability, and a plastic film inner material having low softening point than that of the outer plastic film with an adhesive, and the peripheral part of the packaging material is joined by thermal welding. Thereby, the obtd. oxygen absorbent has extremely excellent air permeability and fast deoxidizing rate. The oxygen absorbent is a cross-sectional absorption type showing enough performance of water resistance and bleeding resistance intrinsic to the plastic films. The obtd. absorbent can be used for foods having high water content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen absorbent used for storage of foods and the like, and is effectively used in the field of food industry.

[0002]

2. Description of the Related Art Conventionally, packaging materials used for oxygen absorbers include paper, non-woven fabrics, plastic films, and materials obtained by combining them. The oxygen absorbers are mainly used for foods. Therefore, among them, a laminated film in which a plastic film having excellent water resistance is used as an exterior material and paper or a non-woven fabric is used as an interior material, and these are laminated is often used. In those laminated films, the water-resistant plastic film itself lacks the air permeability required for the oxygen absorbent to take in oxygen, so it is widely practiced to make holes in the film to ensure air permeability. ing. Oxygen absorbers that use a plastic film made of a perforated film to give air permeability to the film are widely used, but when this is applied to food with high water content, There are many movements of water through the oxygen absorber, and as a result, the oxygen absorber oozes out to contaminate the food, or the appearance is significantly impaired without contaminating the food. As a packaging material for improving the above-mentioned drawbacks, Japanese Patent Laid-Open No. 60-240664 discloses a method in which a non-breathable plastic film is used as an exterior material, and deoxygenation is performed by aeration of gas from the cross section of the sealed portion after packaging. (Cross-section oxygen absorption method) has been proposed. This method
Since it does not use a perforated film as an exterior material, it is an excellent method that makes it possible to prevent the oxygen absorber from seeping out of the package, but on the other hand, it is possible to obtain a packaging material with good gas ventilation. It's also a difficult method. The oxygen absorbent using a packaging material with poor gas permeability is slow in oxygen absorption rate, contains a large amount of water, and is unsuitable for use in foods with rapid deterioration, and the method proposed in that respect is It has a problem.

[0003]

DISCLOSURE OF THE INVENTION The inventors of the present invention used a plastic film as an exterior material to improve the exudation resistance of contents, and further improve the breathability, that is, Since a method for solving the above-mentioned problems was investigated, a large amount of water was contained therein, and a keen study was carried out with the aim of providing an oxygen absorber with a fast deoxidization rate that can be sufficiently used even for foods with fast deterioration. is there.

[0004]

Means for Solving the Problems The present inventors have made various investigations to develop a packaging material for an oxygen absorbent having a fast deoxidization rate even though it is a gas flow system (cross-section oxygen absorption system) from the cross section of the seal portion. As a result, in the method, the components constituting the packaging material are pasted together by heat lamination, and it is determined that the air permeability is deteriorated because the holes of the perforated film are deformed or clogged during lamination, and the exterior material and the intermediate material. And when the interior material is adhesively laminated with dry lamination to minimize heating, the adhesive blocks the holes and lowers the air permeability, which is a method that is considered to be a reverse method originally. The present invention has been completed by finding that a packaging material that can satisfy the target performance can be obtained without being affected by it.

That is, according to the present invention, an exterior material made of a plastic film, an air-permeable intermediate material, and an interior material made of a plastic film having a lower softening point and pores than the plastic film of the exterior material are adhesively laminated with an adhesive. The present invention relates to an oxygen absorber, which is obtained by wrapping a deoxidizer in a wrapping material and joining the peripheral portions by heat fusion.

In the packaging material of the present invention, an exterior material made of a plastic film, an air-permeable intermediate material, and an interior material made of a plastic film having a lower softening point than the plastic film of the exterior material and having pores are adhered and laminated with an adhesive. The oxygen absorbent having the above-mentioned configuration uses the packaging material to absorb gas from the cross section of the seal portion (cross section oxygen absorption method).
However, it has an excellent feature that it has an extremely excellent oxygen absorption rate.

Exterior material As the plastic film used as the exterior material in the present invention, films such as polyethylene terephthalate, polyamide, polypropylene, polyethylene, polycarbonate, polystyrene, polybutadiene, cellophane, polyvinyl alcohol, ethylene-vinyl alcohol and the like can be used. Can be mentioned. Among these, polyethylene terephthalate and polyamide films are preferable from the viewpoints of packaging property and film strength. Further, when importance is attached to the improvement of the deoxidation rate, polystyrene excellent in gas permeability,
It is preferable to use a film such as polybutadiene or polyethylene, and it is particularly preferable for the present invention to use a film having an oxygen permeability of 2000 ml / m ² · 24 hrs · atm or more and excellent gas permeability.

Intermediate Material As the intermediate material, paper or non-woven fabric, which is generally used as a packaging material and also has air permeability, is applied. Examples of the paper include Japanese paper, kraft paper, pure white roll paper, oil resistant paper and the like. Further, as the non-woven fabric, polyester, polyamide, polypropylene, polyethylene,
Examples of the material include materials such as acrylic, and from the viewpoint of the manufacturing method, those manufactured by a dry method, a wet method, a spunbond method, a needle patch method, and the like can be mentioned, and a combination thereof can also be used.

Interior material Since the interior material needs to have ventilation to the intermediate material and heat sealability when packaging the oxygen absorber,
It is a plastic film having a lower softening point than the plastic film of the exterior material and having pores, and any plastic film having a lower softening point than the plastic film used as the exterior material, preferably 10 ° C. or more, can be used. Examples thereof include polyethylene, polypropylene, ethylene vinyl acetate copolymer, ionomer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer, ethylene-acrylic acid copolymer and the like. The pores are provided in the film by a known method such as punching with a hot needle, and are used in a form having air permeability.

Adhesive In the present invention, as an adhesive for adhering the exterior material and the intermediate material, and the intermediate material and the interior material, the adhesive strength is high and the decrease in the air permeability caused by the adhesion is suppressed to a minimum. For this reason, it is preferable to use a room temperature curing type or room temperature drying type adhesive which requires less heating for bonding.
Examples of the room temperature curable adhesive include a two-component type urethane adhesive and a moisture curable urethane adhesive.
Examples of the room temperature dry type adhesive include solvent type adhesives such as acrylic type, olefin type and rubber type. It is desirable to use the same adhesive for adhering the exterior material and the intermediate material, and the intermediate material and the interior material in terms of workability and quality stabilization, but use different adhesives. It doesn't matter. In order to achieve the object of the present invention, it is most preferable to bond and laminate at room temperature using a room temperature curing type or room temperature drying type adhesive, but to accelerate the drying or curing reaction of the solvent. If so, heating at 100 ° C. or lower may be performed, and any thermosetting adhesive that can be used at such a temperature can be used in the present invention. There is no particular method for applying the adhesive to laminate the exterior material and the like, and any known method such as using a roll coater can be used. The adhesive is basically applied to the entire surface of the exterior material and laminated, but in order to improve air permeability, the adhesive may be partially applied such as linear or dotted to be laminated. It is possible. The amount of adhesive applied is preferably 1 to 30 g / m ^{2 and 2} to 10 g / m ^2.
Is more preferable.

Oxygen absorber As the oxygen absorber used in the present invention, an oxygen absorbing agent containing metal powder such as iron powder, ascorbic acid and / or its salt, sulfite salt, bisulfite salt, hydroquinone, catechol and the like. Sex drug, carbon dioxide generating oxygen absorbing drug,
Examples include carbon dioxide absorption type oxygen absorbing agents.

[0012]

The exterior material, the air-permeable intermediate material, and the interior material specified in the present invention are adhered and laminated with an adhesive capable of adhering at room temperature to a relatively low temperature (100 ° C. or less), so that the air permeability is improved. An excellent packaging material can be obtained, and the oxygen absorbent using the packaging material has a very remarkable effect of having a sufficient deoxidizing rate even by only gas flow from the cross section of the seal portion.

[0013]

【Example】

Example 1 A 12 μm polyethylene terephthalate film (exterior material) and a pure white paper (intermediate material) having a basis weight of 50 g / m ² were bonded together with a moisture-curable urethane adhesive (manufactured by Takeda Pharmaceutical Co., Ltd.), and further on the pure white paper side. Perforated polyethylene film with a hole area of 9% and uniform opening with an average diameter of 0.4 mm (film thickness 30μ:
The interior material) was attached using the same adhesive to obtain a packaging material A for oxygen absorbent. Fold the packaging material A with the polyethylene side inside and add 3 g of the oxygen absorber with iron powder as the main component,
The three sides were heat-sealed to obtain an oxygen absorbent having a length of 40 mm × width of 50 mm and a seal width of 5 mm. The oxygen absorbent thus obtained was put together with 500 ml of air in a bag made of KOP (polyethylene chloride coated with polyvinylidene chloride) / polyethylene, hermetically sealed, and left in an atmosphere of 20 ° C. In the stage after 20 hours, 0.4% oxygen remained, but the oxygen concentration after 24 hours was 0.0%.

Example 2 Packaging was performed in the same manner as in Example 1 except that 16 μm polystyrene film (oxygen permeability 5500 ml / m ² · 24 hrs · atm) was used as the exterior material in place of polyethylene terephthalate in Example 1. Material B was obtained. The oxygen absorbent packaged in the same manner as in Example 1 using this packaging material B was evaluated for deoxidation rate under the same conditions as in Example 1, and after 20 hours, the oxygen concentration was 0.0%. there were.

Comparative Example 1 A laminated film obtained by extrusion laminating polyethylene to a thickness of 15 μm on 12 μm polyethylene terephthalate, a pure white paper having a basis weight of 50 g / m ² and holes having an average diameter of 0.4 mm were uniformly opened. Perforated polyethylene film with a porosity of 9% (film thickness 30
μ) was heat-laminated to form a laminated film / paper / polyethylene film to obtain a packaging material C. With respect to the oxygen absorbent packaged in the same manner as in Example 1 using this packaging material C, the deoxidation rate was evaluated under the same conditions as in Example 1, and it was completely deoxidized and the oxygen concentration was 0.0%. It took 80 hours to become.

Comparative Example 2 A packaging material was prepared in the same manner as in Comparative Example 1 except that a modified olefinic hot melt agent (manufactured by Toagosei Kagaku Kogyo Co., Ltd.) was used for laminating the polyethylene terephthalate film and pure white paper. I got D. With respect to the oxygen absorbent packaged in the same manner as in Example 1 using this packaging material D, the deoxidation rate was evaluated under the same conditions as in Example 1, and it was completely deoxidized and the oxygen concentration was 0.0%. To be 7
It took 2 hours.

[0017]

[Effects] The oxygen absorbent of the present invention is very excellent in air permeability, and is a gas absorbent from the cross section of the seal portion (a cross-section absorption type oxygen absorption method), but an oxygen absorbent with a high deoxidization rate, A cross-section absorption type oxygen absorber capable of exhibiting 100% of excellent water resistance and exudation resistance of a plastic film, which has an excellent effect of being able to be used for high-moisture foods, which has hitherto been impossible. Is.

Claims (1)

[Claims] 1. A packaging material in which an exterior material made of a plastic film, an air-permeable intermediate material and an interior material made of a plastic film having pores having a lower softening point than the plastic film of the exterior material are adhered and laminated with an adhesive. An oxygen absorbent characterized by being formed by wrapping an oxygen agent and bonding the peripheral portions by heat fusion.