JP3107466B2 - 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. Oxygen absorbers are mainly used for food applications. 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, a packaging material using creped paper is used as a gas-permeable base material (intermediate material) constituting a gas-permeable layer, and furthermore, an exterior material, an intermediate material, and an interior material are bonded with an adhesive. The present invention has been completed by finding that a packaging material satisfying the target performance can be obtained by using, minimizing the heating and bonding and laminating by dry lamination. In particular, the method using an adhesive has a surprising effect of exhibiting excellent characteristics without being affected by the adhesive, which is a method considered to be a reverse method in which the adhesive closes a hole and lowers air permeability. I found it.

That is, the present invention provides a laminate of an exterior material composed of a plastic film, an intermediate material composed of creped paper 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. The present invention relates to an oxygen absorbent, characterized in that the film thus obtained is used as a packaging material, and a peripheral portion of the package after the packaging of the oxygen absorber is bonded by heat fusion.

The packaging material of the present invention comprises a film in which an exterior material made of a plastic film, an intermediate material made of crepe paper, and an interior material made of a plastic film having a softening point lower than the plastic film of the exterior material and having pores are laminated. In particular, it is made of a film bonded and laminated with an adhesive, and the oxygen absorbent using the packaging material absorbs gas from the cross section of the seal portion (cross section oxygen absorption method).
However, it has an excellent feature that it has a very excellent 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. In addition, 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, crepe obtained by creping a paper which is generally used as a packaging material and has air permeability, for example, Japanese paper, kraft paper, pure white roll paper, oil-resistant paper, or the like is used. Paper is 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 exterior material and the intermediate material, and the intermediate material and the interior material,
Each may be laminated using a heat sealant or utilizing heat fusion of the interior material itself, but in order to better achieve the object of the present invention, it is preferable to adhere with an adhesive, As the agent, a room-temperature-curing or room-temperature-drying type adhesive which requires only a small amount of heating for bonding is preferable in order to minimize the decrease in air permeability caused by bonding and to minimize bonding. 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 so, heating at 100 ° C. or lower may be performed, and any thermosetting adhesive that can be used at such a temperature can be preferably used in the present invention. 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. In addition, the adhesive is basically applied over the entire surface of the exterior material and laminated, but in order to improve the air permeability, the adhesive may be partially applied such as a linear or dot-shaped adhesive and laminated. It is possible. The coating amount of the adhesive is preferably 1 to 30 g / m ^{2, and 2} to 10 g / m ^2.
Is more preferred.

(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]

According to the present invention, creped paper is used as the intermediate material specified in the present invention, and furthermore, the exterior material, the intermediate material, and the interior material can be bonded at room temperature to a relatively low temperature (100 ° C. or lower). By bonding and laminating using an agent, a packaging material having excellent air permeability can be obtained, and the oxygen absorbent using the packaging material has a sufficient deoxygenation rate only by gas flow from the cross section of the seal portion. It shows a very remarkable effect.

[0013]

Example 1 A two-part curable urethane-based adhesive was prepared using a 12 μm polyethylene terephthalate film (exterior material) and a creped pulp paper (intermediate material: Miki Specialty Paper) having a basis weight of 50 g / m ^2. Perforated polyethylene film with a porosity of 9% (thickness: 30μ: interior material) in which holes having an average diameter of 0.4 mm are uniformly formed on the pulp paper side that has been laminated and creped with Takeda Pharmaceutical Co., Ltd. Were bonded 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 absorber containing iron powder as a main component
And heat seal on three sides, length 40mm x width 50m
m and an oxygen absorbent having a seal width of 5 mm were obtained. The oxygen absorbent thus obtained is combined with 500 ml of air in KOP (stretched polypropylene coated with polyvinylidene chloride).
/ Polyethylene and sealed and left in an atmosphere of 20 ° C. Eight hours later, the residual oxygen concentration decreased to 8.2%, and after 24 hours, the oxygen concentration was 0.0%.

Comparative Example 1 A packaging material B was obtained in the same manner as in Example 1 except that pulp paper having a basis weight of 50 g / m ² (no creping treatment, manufactured by Miki Specialty Paper) was used. Was. 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 8 hours, 12% of the oxygen remained. It took 32 hours to completely deoxygenate.

[0015]

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.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A23L 3/3436 B32B 27/10

Claims (1)

(57) [Claims] An exterior material comprising a plastic film,
A package in which an intermediate material made of crepe-treated paper 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 laminated as a packaging material, and a package after packaging an oxygen scavenger is used. An oxygen absorbent characterized in that the peripheral edges of are bonded by heat fusion.