JP2740010B2 - Organic laminated metal body with deoxidation function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a material having a deoxygenation function, and provides a material which prevents deterioration of foods and drinks which are easily affected by oxygen and enables long-term storage. That is.

[Prior art] Conventionally, some foods, beverages, medicines, etc. cause decay, deterioration, and deterioration by contact with oxygen in the air.
As a preventive method, for example, an oxygen scavenger (a reducing organic compound such as a sulfoxylate or a nitrite or an iron powder or the like) which absorbs oxygen together with the contents in a closed container is placed in a gas-permeable container, There is a method of absorbing and removing oxygen in air in a closed container by packing the film in a conductive film.

However, in the above-described method, since a package made of a gas permeable container or a gas permeable film containing a deoxidizer must be sealed together with the contents, there is a risk of reacting with the contents, and especially liquid The fact is that it has not been put to practical use for preserving goods and medicines. Therefore, if the closed container itself can be manufactured from a material having a deoxidizing function, it is easy to handle and can be easily applied to the liquid substance without preparing a separate deoxidizing agent, which is a very useful deoxidizing method. An oxygen method will be provided.

In order to achieve the above object, the present inventors have already developed a material having a deoxidizing function by reacting with oxygen on the surface of an aluminum plate, a tin-plated steel plate, a chromium-plated steel plate or a nickel-plated steel plate which is usually used for containers. A patent application was filed for a method using a material plated with iron, zinc or manganese as a metal which is easy to work with (JP-A-61-295396).
Also promotes the reaction between these metals and oxygen as needed,
In addition, for the purpose of preventing the reaction product from being dissolved again in the contents, a method has been proposed in which a hydrophilic coating layer and an oxygen / water permeable membrane are coated in multiple layers on the metal coating (Japanese Patent Application Laid-Open No. Sho 62). No. -109859). In the above invention, an ordinary wet plating method is used as a method of coating a metal which easily reacts with oxygen. However, the application of wet plating to an aluminum plate is inferior to plating ordinary steel products due to the presence of a strong oxide film on the aluminum surface, and the oxide film is removed immediately before plating. However, there are drawbacks such as the necessity of complicated pretreatment steps and associated wastewater treatment equipment.

[Problems to be Solved by the Invention] The present invention uses a special pretreatment of an aluminum plate which does not react with oxygen due to having a stable oxide film with a metal which easily reacts with oxygen such as iron, zinc, manganese or magnesium. An object of the present invention is to provide a laminate in which a required amount of plating is performed without requiring a step, and a hydrophilic organic coating layer and an oxygen / water permeable polymer coating are coated thereon in multiple layers.

[Means for Solving the Problems] The present invention uses a dry plating method such as vacuum deposition, ion plating or sputtering to deposit a metal that easily reacts with oxygen such as iron, zinc, manganese or magnesium on an aluminum plate. This is to provide a deoxygenation function by coating an amount necessary for removal. At this time, a hydrophilic coating layer as a reaction accelerator is provided on the coated metal, and an oxygen / oxygen layer is further provided thereon as a reaction product blocking layer. A water-permeable polymer membrane is coated in multiple layers (FIG. 1). The hydrophilic coating layer has the function of retaining the water required for the oxidation reaction of the substrate metal on the metal surface. The amount of oxygen that will eventually be encapsulated in the closed container is usually small, so that the amount (thickness) of the metal that reacts with the oxygen to be coated is also small. For example, if the content is beer, dissolved O ₂
The amount is usually around 1 ppm. Now, assuming that the volume of the content is 100 ml, the amount of dissolved O ₂ is 1 ppm, and the inner area of the coating in contact with the content is 100 cm ² , and taking the following reaction with iron as an example, the required amount of iron is 4Fe + 3O ₂ + H ₂ O → 2Fe ₂ O ₃ .H ₂ O 1 × 10 ^-3 (100/1000) × (4 × 55.85 / 3 × 32) = 2.32 × 10 ^-4 g = 0.232 mg Iron density 7.85 g / cm ³ , which is equivalent to only about 30 ° in terms of thickness, indicating that an extremely thin coating is sufficient. This is a coating amount (hereinafter referred to as a basis weight) in a range where the dry coating method, that is, vacuum deposition, ion plating, sputtering, or the like performed in the present invention can be easily applied, and there is no problem in plating adhesion. The vacuum deposition referred to here is a normal method of evaporating and depositing a molten metal in a vacuum of about 10 ^-2 to 10 ^-5 Torr, and ion plating applies a DC voltage (or This is a method of applying a high frequency to the signal. Sputtering is also performed in a vacuum of about 10 ^-3 Torr (including a small amount of Ar gas) by applying a voltage of several hundred volts between an object and a target metal (Fe, Zn, Mn, Mg, etc.). This is a method in which an argon plasma is generated, whereby the target metal is converted into atoms or ions and adhered to the surface of the object. In these dry coating methods, the object to be coated is not necessarily limited to the plate shape, but may be the inner surface of a bottle-shaped object.

In the present invention, a metal that reacts with oxygen is coated and a hydrophilic layer is applied as a reaction accelerator, and in order to prevent the reaction product from dissolving into the contents, an oxygen / water permeable layer is formed on the hydrophilic film. Coat the polymer film. As the hydrophilic substance of the reaction accelerator, a water-soluble polymer is used, which includes starch, gelatin, natural substances such as casein, methylcellulose, ethylcellulose, carboxymethylcellulose,
Cellulose derivatives such as hydroxyethylcellulose, vinyl polymers such as polyvinyl alcohol, polyvinyl methyl ether and polyvinylpyrrolidone, and synthetic polymers such as acrylic acid, methacrylic acid and esters thereof are used. Among them, cellulose compounds are preferable. The water-soluble compound is coated as an aqueous solution by a spray, a roll coater or the like. It is dried by heating if necessary. The coating thickness is usually about 0.1 to 0.5 μm. The oxygen / water permeable membrane, which is applied to prevent the reaction product of oxygen from back-diffusing into the contents, is made of a material having an oxygen permeability coefficient of 10 ^-10 cm ³ .cm / cm ² .sec.cmHg or more. If so, there is no particular need to limit the type. The reason for this is that the water permeation rate of an ordinary polymer membrane is much faster than that of oxygen, and the reaction is limited by the diffusion of oxygen. Materials preferably used for this purpose include polyolefin compounds such as polyethylene, polymethylpentene and polybutadiene, and silicone coatings such as polymethylsiloxane. These are formed into a sheet and coated by thermocompression bonding or an adhesive, or dissolved in an organic solvent and sprayed. Coating thickness is 5μm to 300μm, usually 20-50μm
Is the thickness. When an adhesive is used, generally, a polyester-based, polyurethane-based, polyacrylate-based, modified vinyl-based, modified olefin-based or the like is applied alone or in a mixed form. If necessary, a polyisocyanate, a phenol resin, an epoxy resin, an amine compound and the like may be appropriately added.

[Operation and Effect of the Invention] Compared with the conventional wet plating method, an aluminum plate or a molded product thereof is coated with iron, zinc, manganese or magnesium as a metal layer reacting with oxygen by vacuum deposition, ion plating or sputtering. A stable oxide film by improving the plating adhesion and plating workability, and further coating a hydrophilic layer as a reaction accelerator and an oxygen / water permeable film to prevent reverse diffusion of reaction products Therefore, in a closed container based on an aluminum plate having no reactivity with oxygen as a base, oxygen in the container can be removed to prevent deterioration and deterioration of the contents.

[Example] An example is described below.

Example 1 A rolled aluminum plate for a can was coated with Zn to a thickness of about 100 mm by a vacuum evaporation method. The Zn vapor was evaporated and supplied by heating and melting the granular zinc in the magnetic crucible installed in the vacuum vessel with a heater. The degree of vacuum is 10 ^-4 Torr, and the coating time is 30 seconds. After coating with Zn, hydroxyethylcellulose was coated to a dry film thickness of 0.3 μm, and then a polybutadiene film (50 μm) was hot-pressed with a hot press. Using this as a can lid, the coated surface is on the inside, and the painted aluminum can body (35
0 ml) was filled with beer containing 0.8 ppm of O ₂ and rolled up. After standing at room temperature for 24 hours, the dissolved oxygen meter
When the O ₂ amount was measured, the value was 0.08 ppm, which was reduced to 1/10. On the other hand, in the can using the normal aluminum can lid used for comparison, the O ₂ amount is only 0.4 ppm and a half (the difference from the initial value is due to the reaction with beer), and the material according to the present invention is used. A remarkable deoxygenation effect was observed in the cans used.

Example 2 An aluminum rolled sheet for cans was coated with about 40 ° of Fe by an ion plating method. Evaporated metal iron was prepared in a water-cooled copper crucible, and a 10 kV, 1 kV
Irradiation with a 00 mA electron beam caused rapid dissolution and evaporation. The evaporated iron atoms dissociate the electrons when passing through the electron beam and become positive ions.On the other hand, the aluminum plate to be coated has a DC voltage of -200 V applied between it and the earth, Is deposited on the surface of the aluminum plate. The degree of vacuum is
10 ^-4 Torr, deposition rate 2２ / sec. A 0.3 μm thick hydroxyethylcellulose membrane was coated thereon in the same manner as in Example 1. Further, a polymethylpentene film (thickness: 50 μm) was bonded with a urethane-based adhesive. The thickness of the adhesive at this time was about 1 μm. This multi-layer coated aluminum plate was used as a can lid in the same manner as in Example 1 and filled with beer containing 0.8 ppm of O ₂ . The amount of dissolved O ₂ after leaving at room temperature for 24 hours is 0.03 ppm
And a remarkable deoxygenation effect was recognized.

Example 3 The inner surface of a 350 ml aluminum can body was coated with Fe to a thickness of about 30 ° by sputtering. For this purpose, an iron rod is used as a target material, which is inserted into a can and the whole is placed in a chamber having a degree of vacuum of 10 ^-3 Torr. A DC voltage of 400 V is applied between the target and the target (supporting substrate), and iron is sputtered by the generated argon plasma to adhere to the inner surface of the container. An iron coating of about 30 ° was formed by sputtering for 20 seconds. An aqueous solution of hydroxycellulose was spray-applied to the inside, and after drying, a silicone paint was also spray-applied. This inner surface-coated can was filled with beer in the same manner as in Example 1, and sealed with a usual painted aluminum can lid. The amount of dissolved O ₂ after standing at room temperature for 24 hours was 0.03 ppm, and a remarkable deoxygenation effect was observed.

[Effects of the Invention] As described above, according to the present invention, in a sealed container having an aluminum plate as a base having a stable oxide film and having no reactivity with oxygen, oxygen remaining in the container is reduced for a short period of time. To prevent deterioration and deterioration of the contents.

[Brief description of the drawings]

FIG. 1 is a schematic view of an organic laminated metal body having a deoxidizing function of the present invention. DESCRIPTION OF SYMBOLS 1 ... Aluminum plate 2 ... Metal coating layer that reacts with oxygen 3 ... Hydrophilic organic coating layer 4 ... Oxygen / water permeable polymer coating

Claims (1)

(57) [Claims] 1. A hydrophilic organic coating layer on a substrate in which one or two or more of iron, zinc, manganese and magnesium are coated on an aluminum surface by vacuum evaporation, ion plating or sputtering, and oxygen on the substrate. -An organic laminated metal body having a deoxidizing function formed by coating a water-permeable polymer film.