JP3238483B2 - Oxygen absorber - Google Patents

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 preserving foods and the like, and is effectively used in the field of the food industry.

[0002]

2. Description of the Related Art Conventionally, packaging materials used for oxygen absorbers include paper, non-woven fabric, plastic film, and materials combining them, and the like. Therefore, among these, a laminated film in which a plastic film having particularly excellent performance in water resistance is used as an exterior material, paper or a nonwoven fabric is used as an interior material, and the laminated film is used in many cases. In these laminated films, the plastic film itself, which has excellent water resistance, has poor 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 plastic films made of perforated films to provide breathability to the films are widely used. There is a drawback that the oxygen scavenger seeps out as a result of a large amount of water transfer through, and contaminates the food, or significantly impairs the appearance without contaminating the food. As a packaging material for improving the above drawbacks, Japanese Patent Application Laid-Open No. 60-240664 discloses a method in which a non-breathable plastic film is used as an exterior material, and after packaging, deoxygenation is carried out by passing gas from the cross section of the sealing portion. (Section oxygen absorption method) has been proposed. This method is
This is an excellent method that prevents the oxygen scavenger from seeping out of the package because it does not use a perforated film as an exterior material.However, it is possible to obtain a packaging material with good gas ventilation. It is also a difficult method. An oxygen absorbent using a packaging material with poor gas ventilation has a low oxygen absorption rate, contains a large amount of water, and is unsuitable for use in foods that deteriorate quickly. It has problems.

[0003]

SUMMARY OF THE INVENTION The present inventors have proposed a method of using a plastic film as an exterior material and improving the bleeding resistance of the contents. We studied a method to solve the above problems, and conducted extensive research with the aim of providing an oxygen absorber with a high water content and a high deoxygenation rate that can be used satisfactorily even in foods that deteriorate quickly. is there.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted various studies in order to develop a packaging material for an oxygen absorbent having a high deoxygenation rate while using a gas flow system (cross-sectional oxygen absorption system) from the seal section. As a result, according to the method, the components constituting the packaging material are bonded by heat lamination, and the holes of the perforated film are deformed or clogged at the time of lamination, and it is determined that the air permeability is reduced, so that the exterior material and the intermediate material are determined. And the interior material, using an adhesive, holding down the heating to a minimum, and laminated by dry lamination, the adhesive closes the hole and reduces the air permeability, although it is a method that is considered to be the reverse way originally The present invention was completed by finding that a packaging material satisfying the target performance can be obtained without being affected by the above.

That is, according to the present invention, an exterior material composed of a plastic film, an intermediate material having air permeability, and an interior material composed of a plastic film having a softening point lower than that of the plastic film of the exterior material and having pores are bonded and laminated with an adhesive. A packaging material and the outer material and the intermediate
Bonding between the intermediate material and the interior material
Do not bond using a thermosetting or room temperature drying adhesive.
The present invention relates to an oxygen absorbent characterized in that an oxygen absorber is wrapped with a wrapping material and the peripheral portion is joined by heat fusion.

[0006] The packaging material of the present invention is capable of bonding an exterior material made of a plastic film to an intermediate material having air permeability, and the like.
Plastic film of intermediate and exterior materials with air permeability
Plastic film with softening point lower than lum and pores
Adhesion to interior materials made of
It is composed of an adhesive or a room temperature drying type adhesive bonded and laminated, and the oxygen absorbent using the packaging material is extremely excellent in spite of gas absorption from the cross section of the seal portion (cross sectional oxygen absorption method). It has the excellent feature of having an oxygen absorption rate.

(7) 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. No. Of these, polyethylene terephthalate and polyamide films are preferred from the viewpoint of packaging properties, film strength, and the like. Also, when emphasis is placed on improving the deoxygenation rate, polystyrene with excellent gas permeability,
It is preferable to use a film of polybutadiene, polyethylene or the like, 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 in gas permeability.

[0008] Intermediate material As the intermediate material, paper or nonwoven fabric which is generally used as a packaging material and has air permeability is applied. Examples of paper include Japanese paper, kraft paper, pure white roll paper, oil-resistant paper, and the like. In addition, as a nonwoven fabric, polyester, polyamide, polypropylene, polyethylene,
Materials such as acryl can be used. From the viewpoint of the manufacturing method, those manufactured by a dry method, a wet method, a spun bond method, a needle patch method, and the like can be used, and those obtained by combining them can also be used.

[0009] Interior material Since the interior material needs to have ventilation to the intermediate material and heat sealability when packaging the oxygen scavenger,
Any plastic film having a softening point lower than the plastic film of the exterior material and having pores, and having a softening point lower than the plastic film used as the exterior material, preferably 10 ° C. or more, can be used, For example, films such as polyethylene, polypropylene, ethylene vinyl acetate copolymer, ionomer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer, ethylene-acrylic acid copolymer and the like can be mentioned. The pores are provided by a known method such as piercing the film with a hot needle, and are used in a form provided with air permeability.

Adhesive In the present invention, the adhesive for bonding the exterior material and the intermediate material and the adhesive between the intermediate material and the interior material have a high adhesive strength and also minimize a decrease in air permeability caused by the adhesion. For this purpose, a room temperature drying type adhesive or a room temperature drying type adhesive which requires less heating for bonding is used . Examples of the room-temperature-curable adhesive include a two-part urethane-based adhesive and a moisture-curable urethane-based adhesive. Examples of the room-temperature-curable adhesive include acrylic, olefin, and rubber-based adhesives. Solvent type adhesives may be used. As an adhesive for bonding the exterior material and the intermediate material, and the intermediate material and the interior material,
It is desirable to use the same one in terms of workability and stabilization of quality, but different adhesives may be used. In addition, it is the most preferable to achieve the object of the present invention to bond and laminate at room temperature using a room temperature curing type and room temperature drying type adhesive, but to promote the drying and curing reaction of the solvent. If, heating may be carried out in 100 ° C. or less in some cases. There is no particular method for applying the adhesive to laminate the exterior material, and any method using a known roll coater or the like can be used. Also,
Adhesive is basically applied over the entire surface of the exterior material and laminated, but it is also possible to apply and laminate the adhesive partially or linearly to improve air permeability. is there. The amount of the adhesive applied is preferably 1 to 30 g / m ² ,
-10 g / m < ² > is more preferable.

(1) Oxygen absorber The oxygen absorber used in the present invention includes metal powder such as iron powder, ascorbic acid and / or its salt, sulfite, bisulfite, hydroquinone, catechol and the like. Drugs, carbon dioxide-generating oxygen-absorbing drugs,
Carbon dioxide-absorbing oxygen-absorbing agents and the like can be mentioned.

[0012]

The exterior material, the intermediate material having air permeability, and the interior material specified in the present invention are each bonded and laminated by using an adhesive capable of bonding at room temperature to a relatively low temperature (100 ° C. or lower) to provide air permeability. An oxygen absorbent using the packaging material has an extremely remarkable effect that it has a sufficient deoxygenation rate only by 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 with a moisture-curable urethane-based adhesive (manufactured by Takeda Pharmaceutical Co., Ltd.), and further on the pure white paper side. A perforated polyethylene film having an opening ratio of 9% (thickness: 30 μm) wherein holes having an average diameter of 0.4 mm are uniformly formed.
(Interior material) using the same adhesive to obtain a packaging material A for oxygen absorbent. The packaging material A is folded with the polyethylene side inside, and 3 g of an oxygen scavenger containing iron powder as a main component is added.
The three sides were heat-sealed to obtain an oxygen absorbent having a length of 40 mm, a width of 50 mm and a seal width of 5 mm. The oxygen absorbent thus obtained was put in a bag of KOP (stretched polypropylene coated with polyvinylidene chloride) / polyethylene together with 500 ml of air, sealed, and allowed to stand at 20 ° C. At the stage after 20 hours, 0.4% of oxygen remained, but after 24 hours, the oxygen concentration was 0.0%.

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

Comparative Example 1 A laminated film in which polyethylene was extruded to a thickness of 15 μm on a polyethylene terephthalate of 12 μm, pure white paper having a basis weight of 50 g / m ² , and a hole having an average diameter of 0.4 mm were uniformly formed. Perforated polyethylene film with a porosity of 9% (film thickness 30
μ) was heat-laminated to give a laminated film / paper / polyethylene film structure to obtain a packaging material C. When the oxygen absorbing agent packaged in the same manner as in Example 1 using this packaging material C was evaluated for the deoxidation rate under the same conditions as in Example 1, it was completely deoxygenated 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 olefin-based hot melt agent (manufactured by Toa Gosei Chemical Industry Co., Ltd.) was used for bonding the polyethylene terephthalate film and pure white paper. D was obtained. When the oxygen absorbing agent packaged in the same manner as in Example 1 using this packaging material D was evaluated for the deoxidation rate under the same conditions as in Example 1, it was completely deoxygenated and the oxygen concentration was 0.0%. 7 to be
It took two hours.

[0017]

The oxygen absorbent of the present invention has excellent air permeability and is a gas circulating method (cross-sectional absorption type oxygen absorption method) from the cross section of the seal portion, but has a high deoxygenation rate. A cross-sectional absorption type oxygen absorber that can exhibit 100% of the excellent water resistance and exudation resistance of plastic films, which has an excellent effect of enabling the use of high moisture foods, which was previously impossible. It is.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01J 20/00-20/34

Claims (2)

(57) [Claims] An exterior material comprising a plastic film,
In packaging material and adhesive lamination with an adhesive intermediate material and interior material softening point than the plastic film of the outer package is made of plastic film having pores less having air permeability
And bonding between the exterior material and the intermediate material and
Room temperature curing or room temperature drying
An oxygen absorber characterized in that a deoxidizing agent is wrapped in a packaging material bonded by using a dry-type adhesive, and a peripheral portion is joined by heat fusion. 2. The adhesive according to claim 1, wherein the adhesive is a two-part urethane-based adhesive.
Adhesive or moisture-curable urethane-based adhesive
The oxygen absorbent according to claim 1, which is a thermosetting adhesive .