JPH0867939A - Aluminum alloy and magnesium alloy - Google Patents

Abstract

(57) [Summary] [Object] To provide an aluminum alloy and a magnesium alloy which are continuously oxidized at a predetermined rate in the presence of oxygen, and foils, films, laminated sheets and the like using these alloys. [Structure] (a) a metal selected from the group consisting of aluminum and magnesium, and (b) at least one additive component to be combined with this metal, which is used to continuously oxidize the alloy in the presence of oxygen at a predetermined rate. An alloy comprising an effective amount of additional components to produce.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to aluminum alloys and magnesium alloys that undergo near-continuous complete oxidation. The invention also relates to a packaging material, in particular
The present invention relates to foil, film and laminated sheet materials containing the above alloy.

[0002]

2. Description of the Related Art Metallic aluminum is characterized in that a durable surface oxide layer is instantaneously formed in the atmosphere, and this prevents the progress of metal oxidation. This property of aluminum is an advantage in almost all conventional applications. Aluminum films with aluminum foils and supports are widely used packaging materials. The reason is cheap,
It has no toxicity, is easy to process, can be easily laminated with a polymer film, has an excellent metallic luster, and has durability. This durability derives from its inherent mechanical strength and erosion resistant surface oxide layer.

[0003] Magnesium, which is nontoxic and forms a protective oxide layer like aluminum, is currently used for the same purpose. However, it is not as widely used as aluminum because it is more expensive than aluminum and difficult to process. There are numerous patents on how to enhance this property of aluminum. In each case, the aluminum layer is used as a protective layer, and the purpose is to enhance the erosion resistance of this protective layer. As one of them, U.S. Pat. No. 5,283,118 to Murakami discloses a metallized wrap film having a metal layer formed on one side of a plastic base film. This metal layer is 70
.About.99% aluminum and one or more elements having an atomic number of 12 to 30 to enhance the uniformity and strength of the metal layer and enhance the bondability with the polymer layer.

Many commercial products are susceptible to oxidative erosion during storage, either by the direct chemical action of oxygen or by the action of bacteria in the presence of oxygen. A number of methods have been developed to protect such oxidizable commercial products. For example, they are packaged in an inert atmosphere or hermetically sealed with a thick or laminated polymer film. Can be placed in a package or product, or an antioxidant can be placed in food or medicine.

Cartwright US Pat. No. 5,126,174 proposes a food packaging material in which a plurality of porous polymeric beads are impregnated with an oxygen scavenger.
The beads are attached to the inner surface of the protective material to prevent the well known phenomenon of external air infiltration into the sealed enclosure. Metal scavengers have long been sought in the industry. The only metal that has been practically successful is iron, which has a very slow oxidation rate and the amount of oxygen per gram of oxidation is about 250 cc (in contrast, the amount of oxygen due to oxidation of pure aluminum is about 600 cc per gram). . Another drawback as an oxygen scavenger is that iron is used only as a powder and other components must be added to increase the oxidation rate. Therefore, iron is not suitable for use as a rolled foil, not suitable for being mixed in a polymer material, and cannot be attached onto a polymer film.

None of the other metals have been used successfully as oxygen scavengers. Since aluminum and magnesium have excellent protective properties such that the surface oxide layer prevents the progress of oxidation, there has been no attempt to use them. Today, both aluminum and magnesium are used as rocket fuels. Both of them are suitable for this application because they have a very high oxidation rate in the presence of oxygen. However, this is only true at high temperatures and the presence of the protective oxide layer reduces the oxidation rate. Therefore, it is desired to use a weak protective oxide layer that has an extremely high oxidation rate under the same conditions.

[0007]

SUMMARY OF THE INVENTION The present invention provides significant advantages by making aluminum or magnesium susceptible to continuous oxidation by oxygen within a controllable range, at the expense of some durability. I found that surprising. That is, according to the first aspect of the present invention, a metal selected from the group consisting of aluminum and magnesium, and at least one additive component to be combined with this metal, the alloy is substantially continuous at a predetermined rate in the presence of oxygen. An alloy is provided that includes an effective amount of additive components for effective overall oxidation.

Desirably, the additive component is sodium,
It is selected from the group consisting of potassium, calcium, and barium. According to another aspect of the present invention, there is provided a package containing the above alloy for protecting or heating food products. According to yet another aspect, an oxygen permeable polymeric material, a metal selected from the group consisting of aluminum and magnesium, and an amount effective to substantially continuously oxidize the alloy at a predetermined rate in the presence of oxygen. There is provided a clothing article for warming a part of the body, comprising the alloy according to the above polymeric material, which contains the additive component of.

According to another aspect of the present invention, there is provided a rocket fuel containing the above alloy. Hereinafter, the present invention will be described in more detail by way of examples with reference to the accompanying drawings.

[0010]

The present invention relates to aluminum alloys and magnesium alloys that oxidize continuously in the presence of oxygen at a predetermined rate. This is accomplished by the inclusion of additional ingredients that selectively prevent the formation of a continuous surface oxide layer. This structure allows oxygen to continue to infiltrate the oxide layer that is being formed, and continuously oxidize the entire alloy over time. That is, contrary to the conventional technique intended to strengthen the protective layer of aluminum by adding a material having higher oxidation resistance such as cobalt or silicon, in the present invention, the surface oxide layer is controlled within a controllable range. It is intended to contain a metal or other material that deteriorates.

As used herein, the term “additive ingredient”
Refers to a material added to aluminum or magnesium in small or large amounts (tens of percent) to produce the desired alloy. Suitable additional components include, for example, sodium, potassium, magnesium, calcium, strontium, and barium. As a matter of course, when the protected product is one that enters the human body such as a food product or a medicine, a nontoxic additive component must be selected.

At present, the preferred additive components for aluminum are calcium, sodium or potassium,
Alternatively, it is a combined addition of calcium and sodium or potassium. Calcium is most desirable because it is non-toxic and sufficiently active to bring it to a practical oxidation rate. Furthermore, the activity is mild enough that no new technology needs to be developed to make the packaging material from the aluminum alloy. At present, the preferred additives for magnesium are potassium, sodium, and calcium.

The aluminum alloy of the present invention can be produced, for example, by melting and solidifying the respective components together. A number of sample alloys were made by the following method. The desired amount of aluminum and the desired amount of additive component (s) were charged together in an argon atmosphere in a closed vessel. This mixture was heated at a temperature of about 900 to 1050 ° C. for about 1 to 2 hours to cool the resulting alloy. Aluminum alloys made by this method typically contained about 0.2-40 wt% calcium.

This alloy can be used in various applications. For example, it can be used by pulverizing it in an inert atmosphere to obtain a powder having a desired particle size and putting it in a bag in that state. This powder can be mixed into the polymeric material or inserted between two polymeric sheets. Alternatively, the alloy can be rolled into a foil or a film can be formed on the polymeric support by vacuum evaporation.

FIG. 1 schematically shows a "sandwich" -like laminate according to one embodiment of the present invention, in which a powdered alloy 14 is provided with a polymer support 12 and another polymer layer 16. It is placed between Polymer support 12 and polymer layer 16 may be polyethylene or polypropylene or other suitable polymer. Since the polymer layer 16 faces the oxygen source, it must be oxygen permeable.

The polymer sheet 1 according to the present invention shown in FIG.
8 is a powdery aluminum alloy or magnesium alloy 20 mixed in the polymer layer 22. In this embodiment, the alloy powder is mixed with the polymer powder to make the matrix. Low melting point polymer or paraffin,
It is desirable to use very high concentration alloys. The permeable polymer is mixed with the above base material in an extruder, and a film containing an alloy is extruded.

The alloys of this invention can also be made by vacuum depositing the individual components on a support. As the support material, aluminum foil, polymer materials, cardboard, paper, glass and the like known as support materials for forming laminated materials can be used. One of the advantages of this method is
The point is that the alloy composition can be changed during the vapor deposition process. By changing the amount of additive components that are vapor-deposited at the same time as aluminum, a gradient is created within the layer, and at first 100%
It serves as a protective layer of aluminum and can be gradually transformed into alloys containing effective amounts of other metal (s).

FIGS. 3, 4 and 5 schematically show examples of the alloy film according to the present invention formed by vapor deposition.
The basic laminate 60 shown in FIG.
The alloy layer 64 is vapor-deposited thereon. A polymer or pure aluminum layer can be added to the outside of the basic laminate 60, or an oxygen permeable polymer layer can be added to the inside of the basic laminate 60.

The laminate 66 shown in FIG. 4 is formed by vapor-depositing a layer 68 of an alloy having a continuous composition gradient on a polymer support material 67. The alloy layer 68 may be made in a state where the adjoining portion of the polymer support material is pure aluminum and the amount of the additive component is gradually increased. The laminated body 70 shown in FIG. 5 is composed of an aluminum foil support material 72 acting as an outer protective layer, an alloy layer 74, and an oxygen permeable polymer layer 76 inside. The oxygen permeable layer 76 does not bring the alloy layer 74 into contact with the packaged item to be protected, and at the same time allows the alloy layer 74 to react with oxygen.

The alloy layer formed by vacuum evaporation generally has a thickness of about 5 to 100 μm. The total oxygen absorption capacity is in the range of about 10 to 200 cc / cm ² depending on the thickness of the alloy layer. The method of forming each of the above alloy films is shown in FIGS.
It was shown to. FIG. 6 schematically shows the inside 100 of the high vacuum chamber. Aluminum and calcium or magnesium and sodium (or other additive components according to the invention) are placed in the evaporation vessels 102 and 104, respectively,
Each component has a heater 106, such as a resistance heater.
And heat at 108. The configuration shown is Edwards ™ 3
It may be part of a 06 coating device. High vacuum is 1
It is on the order of 0 ^-6 mb. Support 112 is a suitable support such as glass, polyethylene, polypropylene, or the like. In the vapor deposition process, the alloy layer gathers on the lower surface 114 side of the support material. The amount of individual metal deposited on the bottom surface 114 is a function of the current in the heaters 106 and 108 over a period of time (eg, 40 seconds). Therefore, an electric current suitable for simultaneously depositing different kinds of metals may be applied to individual heaters at desired positions on the support 112.

The apparatus schematically shown in FIG. 7 has a bobbin 12
While rotating 2 around the shaft 124 counterclockwise to unwind the polymer film 120 to be coated, at the same time, while rotating the bobbin 126 clockwise around the shaft 128 to wind the film 120, It is a conventional device for coating. The bobbin 122 is arranged in the vacuum chamber 130, and the bobbin 126 is arranged in the vacuum chamber 132. The polymer film 120 is a chamber 130
Through the opening 138 in the high vacuum chamber 134 and out through the opening 140 in the chamber 132. By evaporation from the container 136 heated by the heater 142,
The polymeric film is coated with a coating material. The laminated sheet of the present invention can be produced by vapor-depositing the aluminum alloy or magnesium alloy of the present invention prepared in advance in the container 136 on the support material using this known apparatus.

Alternatively, the high vacuum chamber 134 of the apparatus can be modified as shown in FIG. 8 to deposit the separate components directly on the support to produce the alloy. As shown in the figure, another evaporation container 144 is provided, and a heater 142 is used to deposit additional components on the polymer film 120. The thickness of the alloy layer is controlled by the temperature of the heater 142, and the amount of additive components in the alloy is controlled by the temperature of the heater 146. The point to be noted here is that a product formed by forming an alloy layer on a polymer film support and winding it into a roll is
It is preferable that the alloy / polymer laminate itself is protected from oxidation during wrapping by wrapping, and it is also preferable that tightly wrapping to prevent air from passing through protects the outer peripheral layer from oxidation. is there.

FIG. 9 shows a modification of the device shown in FIG. In this embodiment, each heater 1
Two evaporation vessels 136 and 14 with 42 and 146
4 and 4 are spaced apart and partially separated by a screen 148. The screen 148 is effective for depositing a mixture of aluminum or magnesium and an additive component at a predetermined ratio on the film 120 (or other support material). First, aluminum or magnesium is vapor-deposited because the element of the additive component (also aluminum element or magnesium element) proceeds almost linearly from the evaporation container to the film 120 in vacuum. Each layer of alloy is added as the film moves through the chamber.

Example 1 An aluminum-calcium alloy consisting of about 20 wt% calcium and about 80 wt% aluminum was prepared. The alloy had a particle diameter of about 1 mm. Oxygen absorption rate is 1.1
It was cc / hr / g. 270 cc of oxygen was absorbed per 1 g of alloy powder in 10 days.

Example 2 An aluminum-calcium alloy consisting of about 5 wt% calcium and about 95 wt% aluminum was prepared. The alloy was crushed into particles with a diameter of about 0.2 mm. The oxygen absorption rate was 0.4 cc / hr / g.

Example 3 A film of aluminum-calcium-sodium alloy was prepared by vacuum deposition on a polypropylene film support. This film was formed from a pre-prepared alloy comprising about 20 wt% calcium and about 0.5 wt% sodium. Oxygen absorption rate is 0.09cc / hr / c
m ² .

Example 4 An aluminum-calcium alloy was prepared by vacuum vapor deposition on a polypropylene film. Metallic aluminum and metallic calcium were placed in a vacuum evaporation system. Adjustment of each heater produced an alloy containing about 40 wt% calcium. Oxygen absorption rate is about 0.06cc / hr / cm
^{Was 2} .

Example 5 A polymer film was coated with an aluminum alloy containing Ca: Al in a weight ratio of 5: 100 by vacuum vapor deposition. When this alloy was placed in a sealed glass container having a constant humidity of 120 ml and kept at room temperature for 4 days, the oxygen concentration in the container decreased from 21% at the beginning to less than 0.01%.

Example 6 A magnesium / potassium alloy film was prepared by vacuum vapor deposition on a polymer support material. The adjustment of each heater produced an alloy layer of about 2 wt% potassium and about 98 wt% magnesium. The oxidation rate was equivalent to that of the aluminum-calcium alloy.

Those skilled in the art are well aware that the rate of oxidation is highly dependent on humidity. That is, the oxidation rate under high humidity may be 10 times or more as high as that under the condition without humidity. The alloys of the present invention have a wide variety of uses, some of which will be described by the following examples.

The alloy of the present invention can be used in the same manner as a conventional oxygen scavenger. In particular, the inclusion of the alloys of the present invention in packaging materials can react with oxygen around oxygen-sensitive items to remove oxygen, thereby extending shelf life. A package containing an aluminum alloy or a magnesium alloy as an oxygen scavenger has the following advantages.

(1) The technology, equipment, and experience necessary for producing an aluminum foil or a laminate of aluminum and a polymer film have been heretofore known and are widely used. (2) Aluminum and magnesium have a very high reaction capacity with oxygen, and 1 g of aluminum can remove 3 liters of oxygen from the air in the standard state (N.T.P.).

(3) When the alloy of the present invention is used, the oxidation of the alloy components contained in the packaging material continues until all the free oxygen in the packaged atmosphere is removed. (4) The produced aluminum oxide and magnesium oxide are chemically inactive and have no toxicity. (5) When the protection-treated product enters the human body, a nontoxic additive component can be easily selected.

(6) The package made of the alloy of the present invention can completely transform into a harmless oxide when exposed to the outside air, and immediately disperses and becomes invisible. is there. 10 and 11 show a package 86 according to one embodiment of the present invention for an article to be protected from oxidation, in a sealed and unsealed state, respectively. Package 8
6 is a plastic container 80 sealed with a laminated foil 82 along a flange 84 that is integrally formed with the container and is bent outward. When it is necessary to contact the contents, at least part of the laminated foil is removed.

In FIG. 11, the foil 82 is shown greatly enlarged to clearly show its laminated structure. What is shown in the figure is a laminate having a four-layer structure, in which a protective layer 94 of aluminum or magnesium without any additive is vapor-deposited on a polymer protective film 92 which is an outer layer. An aluminum alloy or magnesium alloy layer 96 is vapor-deposited on the protective layer 94, and an oxygen permeable polymer layer 98 is coated thereon as an inner layer.

When the container 80 is initially sealed with the foil 82, the oxygen present in the package diffuses through the oxygen permeable layer 98 and reacts with the alloy layer 96 to oxidize the contents of the package. To prevent deterioration due to. The same laminate or foil can be used to prepare the entire container, which can be used for instant food or as a bag of potato chips.

The packages shown in FIGS. 10 and 11 are most easily made of conventional packaging materials that act as a support for depositing the alloys of the present invention. Another layer of oxygen permeable polymer may be added to prevent direct contact between the alloy and the contents of the package. Alternatively, conventional oxygen scavengers can be replaced with the alloys of the present invention. For example, the powdered alloy can be packaged in a bag and inserted into a conventional package to protect the product therein.

The aluminum alloy foil of the present invention can be produced by cold rolling or hot rolling an alloy produced in advance. High temperature alloy sheets and liquid alloys need to be protected from oxidation by processing in an inert gas atmosphere substantially free of oxygen. As an example of the application of the foil, a laminate having a very thin protective layer as an outer layer and a thin oxygen-permeable polymer protective layer as an inner layer is formed, and this is molded to form a can or canned beer or non-alcoholic beverage. Grocery,
It can be a bottle cap and so on. These products have the advantage that they are durable, protect the food in the package and are completely degradable.

The alloy of the present invention can be used in various applications other than the above. Those skilled in the art will recognize that the oxidation process is an exothermic process. Utilizing this fact, various alloys are prepared by selecting the amount of additive components and adjusting the rate of heat generation that can be used to obtain the desired rate of heat, for example, to warm foods, wear clothing for winter, or use as a bandage on the body of the wearer. It can be used as a heater for heating a part of the.

That is, a package such as that shown in FIGS. 10 and 11 can be used in combination with a suitable alloy according to the present invention to warm foodstuffs as contents.
A suitable heater material is an outer alloy layer coated with a removable protective layer. A heat conducting layer should be placed between the alloy and the food item to avoid direct contact between the two. Removal of the removable protective layer exposes the alloy to oxygen, causing oxidation and heating of the package contents.

FIG. 12 shows a sock or inner boot 30 that can be made and implemented according to one embodiment of the present invention.
Is schematically shown as an example. Socks 30 in the illustrated example
Is molded by extruding a mixture of the oxygen-permeable polymer material 32 and the alloy powder 34 of the present invention. The sock 30 is hermetically sealed with a protective cover (not shown) until it is used. This sock is entirely permeable to oxygen, so if you remove the protective cover it will
The alloy 34 in 0 oxidizes and generates heat. Similarly, other apparel items, such as gloves, vests, hats, etc., can be made.

According to another embodiment of the invention, the above garment is made by sandwiching the alloy between two polymeric layers (FIG. 2) or two layers of paper. Similarly, as rocket fuel, suitable alloys according to the invention can be used in place of the aluminum and magnesium fuels used today. The alloys of the present invention are preferred because they have a very fast oxidation rate. Since the protective oxide outer layer according to the present invention is much weaker than that formed on the surface of pure aluminum or pure magnesium, the oxidation rate of the alloy is very high, resulting in a large rocket thrust.

As will be appreciated by those skilled in the art, the present invention is not limited to what has been illustrated above. The scope of the present invention is limited only by the claims.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a laminate according to one embodiment of the present invention.

FIG. 2 is a sectional view schematically showing a flexible sheet material according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view schematically showing a flexible laminated material according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a flexible laminated material according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view schematically showing a flexible laminated material according to one embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a portion of an apparatus for producing an alloy according to one embodiment of the present invention.

FIG. 7 is a cross-sectional view schematically showing a conventional apparatus for coating a polymer film with aluminum by evaporation in a vacuum.

8 is a cross-sectional view showing the apparatus of FIG. 7 prepared to produce an aluminum alloy or magnesium alloy according to the present invention.

9 is a cross-sectional view showing the apparatus of FIG. 8 prepared to produce an aluminum alloy or a magnesium alloy according to another embodiment of the present invention.

FIG. 10 is a perspective view showing a closed state of the package according to the embodiment of the present invention.

FIG. 11 is a perspective view showing a state where the package of FIG. 10 is opened.

FIG. 12 is a perspective view showing an example of a clothing article manufactured from the laminate of FIG.

[Explanation of symbols]

12 ... Polymer support material 14 ... Powder alloy 16 ... Polymer layer 18 ... Polymer sheet 20 ... Powder aluminum alloy or magnesium alloy 22 ... Polymer layer 30 ... Socks or inner boots 32 ... Oxygen permeable polymer Material 34 ... Alloy powder 60 ... Basic laminate 62 ... Polymer support material 64 ... Alloy layer 66 ... Laminate body 67 ... Polymer support material 68 ... Alloy layer 70 having continuous composition gradient 70 ... Laminate body 72 ... Aluminum Foil support material 74 ... Alloy layer 76 ... Oxygen permeable polymer layer 80 ... Plastic 82 ... Laminated foil 84 ... Flange 86 ... Package 92 ... Polymer protective film 94 ... Additive-free aluminum or magnesium protective layer 96 ... Aluminum alloy Or layer of magnesium alloy 98 ... Oxygen permeable polymer layer 100 ... Interior of high vacuum chamber 102, 10 4 ... Evaporation container 106, 108 ... Heater 112 ... Support material 114 ... Support material lower surface 120 ... Polymer film 122, 126 ... Bobbin 124, 128 ... Shaft 130, 132 ... Vacuum chamber 136, 144 ... Evaporation container 138, 140 ... Openings 142, 146 ... Heater 148 ... Screen

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C22C 23/00 C23C 14/06 Z 8939-4K

Claims (25)

[Claims] 1. The following components: (a) a metal selected from the group consisting of aluminum and magnesium, and (b) at least one additive component in combination with the above metals, which is a continuous alloy in the presence of oxygen. An alloy comprising additional components in an amount effective to produce a satisfactory overall oxidation at a predetermined rate. 2. (a) The metal is aluminum,
(b) The additive component is selected from the group consisting of sodium, potassium, calcium, and barium.
The listed alloy. 3. (a) the metal is magnesium,
The alloy according to claim 1, wherein (b) the additive component is selected from the group consisting of sodium, potassium, and calcium. 4. The alloy according to claim 1 in powder form. 5. The alloy of claim 4, wherein the metal is aluminum and (b) the additive component is selected from the group consisting of sodium, potassium, calcium, and barium. 6. An alloy film comprising the alloy of claim 1 on a support material. 7. The alloy film according to claim 6, wherein the alloy is vacuum-deposited on the support material. 8. (a) The metal is aluminum,
(b) The additive component is selected from the group consisting of sodium, potassium, calcium, and barium.
The alloy film described. 9. An alloy film in which the alloy according to claim 1 in a powder state is mixed in an oxygen permeable polymer material. 10. (a) The metal is aluminum,
(b) The additive component is selected from the group consisting of sodium, potassium, calcium, and barium.
The alloy film described. 11. An alloy foil obtained by rolling the alloy according to claim 1 into a foil. 12. A layer of the alloy of claim 1;
(b) A flexible laminated sheet material comprising at least one polymer layer bonded to at least one side of the alloy layer. 13. The flexible laminated sheet material according to claim 12, wherein at least one of the at least one polymer layer is an oxygen-permeable polymer layer. 14. The flexible laminated sheet material of claim 12, further comprising an outer barrier layer. 15. The flexible laminated sheet material of claim 14, wherein the outer barrier layer is selected from the group consisting of an undoped aluminum layer and an oxygen impermeable polymer layer. 16. A package comprising the alloy of claim 1 for packaging an article to be protected from oxygen oxidation. 17. A package comprising the alloy of claim 2 for packaging an article to be protected from oxygen oxidation. 18. A package comprising the alloy of claim 1 for heating food products. 19. A clothing article for warming a body part, comprising (a) an oxygen-permeable polymeric material and (b) the alloy of claim 1 together with said polymeric material. 20. (a) The metal is aluminum,
(b) The additive component is selected from the group consisting of sodium, potassium, calcium, and barium.
Clothing item according to 9. 21. The apparel of claim 19, wherein the alloy is in the polymeric material. 22. The garment according to claim 19, wherein the alloy powder is sandwiched between two layers of the polymer material. 23. Rocket fuel comprising the alloy of claim 1. 24. (a) The metal is aluminum,
(b) The additive component is selected from the group consisting of sodium, potassium, calcium, and barium.
Rocket fuel described in 3. 25. (a) The metal is magnesium,
24. The rocket fuel of claim 23, wherein (b) the additive component is selected from the group consisting of sodium and potassium.