JPS632648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a packaging material for the purpose of removing oxygen. Currently, methods for extending the shelf life of foods include adding antioxidants, vacuum packaging, nitrogen gas filling packaging, carbon dioxide gas filling packaging, and the like. However, for example, in general gas-filled packaging, the residual oxygen concentration is around 2%, and the effect of inhibiting oxidation on oily sweets and the like is low. Recently, attempts have been made to use oxygen absorbers in bags. The residual oxygen concentration is suppressed to 1% or less, and various oxygen scavengers have been put into practical use because they have excellent antioxidant effects.

However, conventionally used oxygen absorbers must be packaged in small bags to prevent them from being accidentally eaten, and oxygen absorber sachets, especially those used for packaging foods, medicines, etc., are easily packaged. The bag had to be constructed so that it could not be torn, thereby preventing personal injury caused by licking the oxygen absorber or putting it into the mouth.

Furthermore, since the oxygen absorber bag is enclosed in the packaging container, there is a problem in that the oxygen absorber bag must be enclosed in the packaging bag together with the product during packaging.

The present invention was discovered as a result of research to solve these difficulties.

That is, the gist of the present invention is mainly characterized by a sheet-like product made by molding into a sheet a mixture of a thermoplastic resin and a thermoplastic resin blended with an oxygen scavenger made of ferrous oxide, which is in a state where it is easy to absorb oxygen. This is an oxygen absorbing sheet.

The oxygen-absorbing sheet according to the present invention includes (i) adhering the oxygen-absorbing sheet to the inner wall of the packaging bag, and (ii) clamping and fixing a part of the oxygen-absorbing sheet to the sealing part of the packaging bag to place the oxygen-absorbing sheet inside the packaging bag. (iii) The oxygen-absorbing sheet is used in the form of forming part of pouches, trays, etc., and is used not only for food products, but also for insect-proofing, mold-proofing of clothing, rust-proofing of metals, and for preventing chemicals. It is useful for preventing deterioration and has an extremely wide range of applications.

In addition, although the conventional packaging form was limited to enclosing the product together with an oxygen absorber bag in a bag or a molded container, the present invention makes it possible to use a packaging form such as a pristar pack.

Furthermore, the packaging material according to the present invention can be used as a constituent material of the membrane of the inner sealing material to perform oxygen-reducing packaging.

The packaging material according to the present invention can be used not only as a constituent material of trays and pouches, but also as a constituent material of (1) a membrane of an inner seal, (2) a constituent material of a mount of a prister pack, and (3) a constituent material of a bottle cap. It can be applied to sealing materials, etc.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows one embodiment of the oxygen absorbing sheet according to the present invention.

Polyethylene, ethylene-vinyl acetate copolymer, or ethylene-methacrylic acid copolymer is coated with metal ions on both sides of sheet-like material 1, which is made by molding an oxygen scavenger made of ferrous oxide into a thermoplastic resin into a sheet shape. An air-permeable overcoat layer 2 of a polymer (ionomer) cross-linked between chains is provided.

In the above embodiment, the breathable overcoat layer 2
is provided to prevent the sheet-like material 1 from coming into direct contact with the product to be enclosed together and to impart heat sealability to the surface, and the surface of the sheet-like material 1 is exposed. It is not necessary if there is no problem in use or if heat sealability is not required.

Further, in the above embodiment, the surface of the sheet-like product is exposed to the atmosphere through the breathable overcoat layer 2, but polyvinylidene chloride, polyvinyl, etc., which have low breathability and are easily peeled off, are coated on the breathable overcoat layer 2. It is also possible to laminate plastic such as alcohol or aluminum foil and peel it off during use to expose the two sides of the breathable overcoat layer. In this case, the deoxidizing effect of the sheet-like material 1 is maintained almost unchanged until it is used.

In the oxygen-absorbing sheet according to the present invention, the content of ferrous oxide is preferably 80% or less, and a content of 80% or more is not desirable because the moldability deteriorates.

Next, as the resin to be blended with ferrous oxide, thermoplastic resins such as polyethylene, polystyrene, polypropylene, polyamide, polyester, etc. can be used.

FIG. 2 shows another embodiment of the oxygen absorbing sheet according to the present invention.

Polyethylene, ethylene-vinyl acetate copolymer, or ethylene-methacrylic acid copolymer is coated with metal ions on one side of sheet-like material 1, which is made by molding an oxygen scavenger made of ferrous oxide into a thermoplastic resin into a sheet shape. An air permeable overcoat layer 2 made of interchain cross-linked polymer is provided on the other side, and a synthetic pulp paper 3 made by mixing paper pulp with a synthetic pulp made of polyethylene is provided on the other side.

In the above second embodiment, the synthetic pulp paper 3
plays the role of a support, but the reason why we chose synthetic pulp paper instead of ordinary paper as the support is that ferrous oxide has an oxygen absorbing effect. The humidity of the surrounding atmosphere must be above a certain limit, but if it is near the paper, the humidity of the atmosphere around the ferrous oxide will decrease due to the moisture absorption effect of the paper, and the ferrous oxide will no longer exhibit an oxygen absorption effect. It is from.

Next, the present invention will be specifically explained with reference to Examples.

Example 1 Oxygen scavenger made of ferrous oxide with a particle size of 5μ and polyethylene (Mirason-11, manufactured by Mitsui Polychemicals)
Mixed at a weight ratio of 20:80 and extruded to a thickness of 0.1
An oxygen absorbing sheet according to the present invention having a size of mm was created.

Example 2 Oxygen scavenger made of ferrous oxide with a particle size of 30μ and polyethylene powder (Frozen UF-80, manufactured by Seitetsu Kagaku)
were mixed at a weight ratio of 20:80 and heated at 170℃ using a heat press machine.
Hot pressing was carried out for 10 minutes to produce an oxygen absorbing sheet according to the present invention having a thickness of 0.8 mm.

Example 3 Low-density polyethylene with a thickness of 50μ was hot-pressed on both sides of the 0.1mm-thick sheet prepared in Example 1, and
An oxygen absorbing sheet according to the present invention having a thickness of 0.2 mm was prepared.

Example 4 One side of the 0.1 mm thick sheet prepared in Example 1 was made by mixing synthetic pulp made of polyethylene and paper pulp at a weight ratio of 50:50 to produce a sheet with a basis weight of 60 g/m ²
An oxygen-absorbing sheet according to the present invention was prepared by laminating synthetic pulp paper using a hot press, and laminating 50 μm low-density polyethylene on the opposite side.

The oxygen absorbing sheets of Examples 1 to 4 above
100mm x 200mm is inserted into a packaging bag made of a laminated film made of polyvinylidene chloride coated polyamide film (150mm x 250mm) laminated with 50μ of polyethylene, completely sealed and stored at a temperature of 30℃, and stored over time. Changes in oxygen concentration were investigated. As a result, as shown by curve 4 in the graph of FIG. 3, it was confirmed that the residual oxygen was 0.5% or less after 72 hours, and a good deoxidizing effect was achieved. Curve 5 in the graph of Figure 3 shows the case where a paper tray was placed inside the packaging bag in the above experiment, and when the paper tray was inside the bag, the curve 5 was compared to when it was not inside the bag. This indicates that the degree of oxygen absorption is slightly slower.
Next, a 100 mm x 200 mm oxygen absorbing sheet of Examples 1 to 4 was inserted into the bag along with 100 g of fried rice crackers, and the bag was completely sealed, and the bag was stored at room temperature to examine changes in peroxide value over time. As a result, as shown by curve 6 in the graph shown in Figure 4, the peroxide value is kept low at 10 meg/Kg or less even after 30 days, oil and fat oxidation is suppressed, flavor is retained, and the packaging material of the present invention It was confirmed that the quality maintenance effect was sufficiently achieved. In FIG. 4, curve 7 shows the peroxide value when wrapped in vinylidene chloride resin coated nylon/polyethylene.

As detailed above, the oxygen absorbing sheet according to the present invention is (i) provided inside the packaging bag by being attached to the inner wall of the packaging bag or clamped and fixed to the sealing part, and (ii) the sheet is used to hold the container together. It can be used as an oxygen absorber in a form such as forming a part, and does not require sachet packaging, and also saves the effort of enclosing the oxygen absorber bag together with the packaged item in the packaging bag during packaging. It will be destroyed. In addition, the oxygen absorbing sheet according to the present invention can be applied not only to maintaining the quality of foods, but also to preventing insects and mildew on clothing, preventing rust on metals, and preventing the quality of chemicals.
Its wide range of applications is extremely wide.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a first embodiment of an oxygen-absorbing sheet according to the present invention, FIG. 2 is a cross-sectional view of a second embodiment of an oxygen-absorbing sheet according to the present invention, and FIG. 3 is a change in oxygen concentration over time. FIG. 4 is a graph showing changes in peroxide over time. 1...Sheet-like material of thermoplastic resin containing an oxygen scavenger made of ferrous oxide, 2...Breathable overcoat layer, 3...Synthetic pulp paper.

Claims (1)

[Scope of Claims] 1. An oxygen-absorbing sheet characterized by mainly comprising a sheet-like material formed by blending an oxygen scavenger made of ferrous oxide with a thermoplastic resin into a sheet-like material. 2. The method according to claim 1, wherein both sides of the sheet-like material are coated with polyethylene, ethylene-vinyl acetate copolymer, or a polymer obtained by interchain-crosslinking an ethylene-methacrylic acid copolymer with metal ions. Oxygen absorption sheet. 3. A synthetic pulp paper made by mixing paper pulp with a synthetic pulp made of polyethylene is pasted on one side of the sheet-like material, and the other side is coated with polyethylene. Oxygen absorption sheet.