JP3222223B2 - 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 the movement of moisture through the water, contaminating the food, or significantly impairing the appearance without contaminating the food. As a packaging material to improve the above disadvantages,
Japanese Patent Application Laid-Open No. Sho 60-240664 proposes a method in which a non-breathable plastic film is used as an exterior material, and after packaging, deoxygenation is performed by passing gas from the cross section of the seal portion (cross-sectional oxygen absorption system). ing. This method is
Because it does not use a perforated film as the outer material, it is an excellent method that can prevent the oxygen scavenger from seeping out of the package, but it is difficult to obtain a package with good gas permeability. It is also a method. Oxygen absorbents that use packaging materials with poor gas ventilation have a low oxygen absorption rate and are unsuitable for use in fast-changing foods that contain a lot of moisture. 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, in which the air permeability is further improved. 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, in the method, the components constituting the packaging material are bonded by heat lamination, and the holes of the perforated film are deformed or stacked at the time of lamination. As a result of examining a method of maximizing air permeability for the method of forming a perforated plastic film and the method of laminating the film and the air-permeable packaging material, it was found that a packaging material satisfying the target performance can be obtained. The present invention has been completed and found.

Namely, the present invention is irradiated with a hot needle into a sheet having a laminated plastic film and breathable, the breathable composite film formed by joining the Rutotomoni both to impart breathability provided a hole in the plastic film ventilation A plastic film having a softening point higher than that of the above-mentioned plastic film is applied to the sheet having the property using a two-component urethane adhesive.
The bonded laminate is used as a packaging material, and the oxygen-absorbing component is packaged with the perforated plastic film surface of the packaging material as the inner surface,
The present invention relates to an oxygen absorbent characterized in that a peripheral portion of a package is sealed by heat sealing.

The packaging material used for the oxygen absorbent of the present invention will be described in more detail. First, a plastic film serving as an inner surface (hereinafter referred to as an interior material) and a breathable sheet are laminated, and a number of heated needles are passed through the laminated body from the plastic film serving as the interior material through a plurality of heated needles. By inserting a large number of fine holes in the plastic film by simultaneously inserting the plastic film, the molten portion of the plastic film melted around each of the thermal needles is welded or entangled to the adjacent air-permeable sheet, The interior material and the air-permeable sheet are joined at a number of hot needle insertion portions to form a breathable composite film, and a plastic film having a higher softening point than the plastic film of the interior material is provided on the air-permeable sheet side of the composite film. (Hereinafter, referred to as an exterior material) as an exterior material. The oxygen absorbent of the present invention, in which the deoxidized component is wrapped with this wrapping material and the peripheral portion of the package is sealed by heat sealing, is obtained by gas absorption from the cross section of the seal portion (cross-section absorption type oxygen absorption method). However, it has an excellent feature of having a very excellent oxygen absorption rate.

[0007] Interior material [0007] As the plastic film used as the interior material in the present invention, any film can be used as long as it is a material usually used as a sealant for a packaging material. Examples thereof include polyethylene, polypropylene and ethylene acetate vinyl. Copolymer, an ionomer, an ethylene-acrylate copolymer, an ethylene-methacrylate copolymer, an ethylene-acrylic acid copolymer, and the like, and a multilayer film may be used.

A sheet having air permeability As a sheet having air permeability, any sheet, such as paper or nonwoven fabric, which is generally used as a packaging material, can be used as long as it has air permeability. For example, as paper
Examples include Japanese paper, pulp paper, kraft paper, pure white roll paper, oil-resistant paper, and the like. As the nonwoven fabric, a material having a softening point higher than that of the plastic film of the interior material, preferably 1
Any material having a high softening point of 0 ° C. or higher can be used. Examples of the material include polyester, polyamide, polypropylene, polyethylene, and acryl. , A spun bond method, a needle patch method and the like, and a combination thereof can also be used. In particular, paper-based papers, especially Japanese paper and pulp paper, are preferred from the viewpoint of welding with plastic films and entanglement. Further, a crepe or the like may be applied to paper or the like to create a space between the paper or the like and the film, and a material having further improved air permeability may be employed.

Exterior material The plastic film used as an exterior material in the present invention has a softening point higher than that of an interior material plastic film used as a heat sealing material, preferably 10%.
Any film can be used as long as it is a plastic film having a high temperature of at least C.C. When the lamination with the interior material is performed by heat lamination, a film having a lower softening point than that of the exterior film, for example, laminated with low density polyethylene or the like is used. When the improvement of the deoxygenation rate is emphasized, it is preferable to use a film having excellent gas permeability such as polystyrene, polybutadiene, or polyethylene, and the oxygen permeability has a performance of 2000 ml / m ² · 24 hrs · atm or more. It is particularly preferable for the present invention to use a film having excellent gas permeability.

Oxygen-absorbing component As the oxygen-absorbing component used in the present invention, oxygen absorption containing metal powder such as iron powder, ascorbic acid and / or a salt thereof, sulfite, bisulfite, hydroquinone, catechol, etc. Drugs, carbon dioxide-generating oxygen-absorbing drugs,
Carbon dioxide-absorbing oxygen-absorbing agents and the like can be mentioned.

Production method of packaging material The packaging material used in the present invention is produced by the following means. First, there is a method in which a plastic film as an interior material and a breathable sheet are processed with a hot needle to form a breathable composite film.
The method described in JP-A No. 21 is applied, a laminate of a plastic film and a gas-permeable sheet is passed between a heating roll and a cooling roll having a large number of needles, and the heated needles are placed on the plastic film side. The plastic film around the hot needle is melted at the same time by inserting many air holes into the plastic film without penetrating through the air-permeable sheet from the plastic film. A sheet having air permeability is joined.
At this time, the adhesive strength is not necessarily high, but has sufficient strength for the purpose of the present invention.
In addition, the method using a roll as described above is a preferable method because of good productivity and a method using a roll as described above. However, the method is not limited to this, and a method using a press or the like can be used. On the breathable sheet side of the breathable composite film,
As a method for bonding the high plastic film softening point than the plastic film of the interior laminate, breathable
From the point of view of productivity and
The dry lamination method used is preferably adopted
You .

[0012]

By laminating and bonding the interior material having excellent air permeability defined in the present invention to the exterior material, a packaging material having excellent air permeability can be obtained. This shows a very remarkable effect that a sufficient deoxygenation rate is obtained only by gas flow from the cross section.

[0013]

【Example】

Example 1 30 μm ethylene vinyl acetate copolymer (EV for short)
A) A film and a pulp paper (manufactured by Miki Special Paper) having a basis weight of 50 g / m ² are laminated, and holes having an average diameter of 0.4 mm are uniformly formed in the EVA film using a heating roll having a large number of perforating needles ( The EVA film and the pulp paper were adhered together with an opening ratio of 9% to obtain a breathable composite film. Further, a 12 μm polyethylene terephthalate film was bonded to the paper side of the breathable composite film with a two-component curable urethane-based adhesive (manufactured by Takeda Pharmaceutical Co., Ltd.) to obtain a packaging material A for an oxygen absorbent. The packaging material A was folded with the EVA side inside, 3 g of a deoxidizing component containing iron powder as a main component, and heat sealed on three sides 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 into a bag of KOP (stretched polypropylene coated with polyvinylidene chloride) / polyethylene together with 500 ml of air, and allowed to stand at 20 ° C. The concentration of residual oxygen decreased to 3.8% at the stage after 8 hours, and the oxygen concentration after 24 hours was 0.0%.

Example 2 In Example 1, the basis weight was changed to 50 instead of pulp paper.
A packaging material B was obtained in the same manner as in Example 1 except that pulp paper (manufactured by Miki Specialty Paper Co., Ltd.) creped with g was used. The oxygen absorbing agent packaged in the same manner as in Example 1 using this packaging material B was evaluated for the deoxidation rate under the same conditions as in Example 1. After 8 hours, 1.9% of the oxygen absorbent remained. The oxygen concentration decreases, and the oxygen concentration after 24 hours is 0.0%
Met.

REFERENCE EXAMPLE 1 In Example 1, a laminated film obtained by extrusion-laminating polyethylene to a thickness of 15 μm on a polyethylene terephthalate film of 12 μm was used as an exterior material, except that the film was laminated with a breathable composite film and heat lamination. A packaging material C was obtained in the same manner as in Example 1. The oxygen absorbing agent packaged in the same manner as in Example 1 using this packaging material C was evaluated for the deoxygenation rate under the same conditions as in Example 1. As a result, after 8 hours, the oxygen absorbent remained at 5.0%. The oxygen concentration decreased, and the oxygen concentration after 24 hours was 0.0%.

Comparative Example 1 A laminated film in which polyethylene was extruded and laminated 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 D. 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. As a result, the oxygen absorbent was completely deoxygenated and the oxygen concentration was 0.0%. It took 80 hours to become.

[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. 100% of the excellent performance of plastic film against water resistance and bleeding resistance, and has an excellent effect that it can be used in high moisture foods, which was previously impossible with cross-sectional absorption type oxygen absorbers. Things.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinji Nakamura 1 at Funamicho, Minato-ku, Nagoya-shi, Aichi, Japan Toagosei Chemical Industry Co., Ltd. Nagoya Research Institute (56) References JP-A-60-240664 ( JP, A) JP-A-62-109621 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A23L 3/00-3/3598

Claims (1)

(57) [Claims] 1. A gas-permeable sheet side of a gas-permeable composite film obtained by applying a thermal needle to a laminated plastic film and a gas-permeable sheet to form a hole in the plastic film to impart gas-permeability and joining them together. Then, a laminate obtained by bonding a plastic film having a softening point higher than that of the plastic film using a two-component urethane-based adhesive is used as a packaging material, and the oxygen-absorbing component is packaged with the perforated plastic film surface of the packaging material as the inner surface. An oxygen absorbent characterized in that a peripheral portion of a package is sealed by heat fusion. "