JPH04220104A - Aluminum foil with hologram relief pattern and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an aluminum foil excellent in heat resistance and wear resistance by providing a hologram relief pattern executing cold rolling or photographic printing to an aluminum foil. CONSTITUTION:A photoresist layer 2 is formed on a metallic foil 1, next, a hologram relief pattern is printed, developed and the strongly exposed resist layer 2 is removed. Further, etching pitches 3 are formed in parts without the resist layer 2 by etching method, the resist layer 2 is removed and projecting and recessed parts corresponding to the hologram relief pattern are formed on the surface of metallic foil 1. This metallic foil 1 is set by coiling it around a rolling roll and rolled. As another method, a photoresist layer 11 is formed by applying a photoresist ink on the surface of the aluminum foil 10, the image of the hologram relief pattern is printed on the layer 11 and the surface of the aluminum foil 10 is exposed by developing. The layer 11 is hardened, an anodically oxidized film 12 is formed by applying anodic-oxidation and, after that, the resist layer 11 is removed with a remover.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum foil having a holographic relief pattern and a method for manufacturing the same.

0002

[Prior Art] Holograms have recently been used on magazine covers, credit cards, and ID cards in the publishing and printing fields.
It has also come to be used to prevent counterfeiting of banknotes.

[0003] The holograms used in these are all formed by hot-stamping the hologram relief pattern of a metal stamper onto a synthetic resin, and then depositing metal on top of it to give it reflectivity. .

However, since synthetic resin is used, heat resistance and abrasion resistance are insufficient, and problems have arisen, such as accidents in which holograms disappear during use.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hologram having heat resistance and wear resistance, and a method for manufacturing the same.

[0006]

[Means for Solving the Problems] In order to solve the above problems, in the first invention, an integral hologram relief pattern is provided on the surface of the aluminum foil.

[0007] The second invention also provides a method of transferring a hologram relief pattern onto the surface of an aluminum foil by providing a hologram relief pattern on a rolling roll and cold rolling the aluminum foil using the rolling roll. It was adopted.

Furthermore, in the third invention, a photoresist layer is formed on the surface of the aluminum foil, an image of a hologram relief pattern is printed by irradiation with ultraviolet rays or a laser beam, and after development, anodization treatment is performed,
The remaining photoresist layer was then removed to form a holographic relief pattern on the surface of the aluminum foil.

[0009]

[Operation] Since the hologram relief pattern is integrally formed on the surface of the aluminum foil, it has heat resistance and wear resistance.

[0010] The above-mentioned hologram relief pattern may be formed by transferring a pattern provided on a rolling roll in a rolling process, or may be formed by photo-printing, developing, and then anodizing. I can do it.

[0011]

EXAMPLES The present invention will be described in more detail below.

First, the aluminum foil used to form the hologram relief pattern is not particularly limited, but a hard or soft foil with an excellent surface gloss and a thickness of 7 to 200 μm is suitable. The thickness of the foil is preferably 50 μm or more in consideration of workability during winding.

A method of forming a hologram relief pattern by rolling using such aluminum foil will be explained.

First, the relief pattern may be formed by transferring it to an aluminum rolling roll, but it is also possible to form the hologram relief pattern on a metal foil or metal sheet that is harder than aluminum, such as Ni or stainless steel. A simple method is to set this on a rolling roll. FIG. 1 shows the process of forming a hologram relief pattern. As shown in FIG. 1(a), a photoresist layer 2 is formed on a metal foil 1 such as Ni or stainless steel, and then
As shown in b), the hologram relief pattern (negative) is printed and developed, and the strongly exposed resist layer 2 is removed. Furthermore, as shown in FIG.
When the resist layer 2 is removed as shown in FIG. 1(d), irregularities corresponding to the hologram relief pattern are formed on the surface of the metal foil 1. This metal foil 1 is wound around a rolling roll and set.

[0015] Regarding the rolling conditions, foil rolling may be carried out at a light reduction of about 30% or less, or cold rolling may be carried out under skin pass conditions.

[0016] The aluminum foil to be transferred is preferably a hard foil. This is because there is less picking up on the embossing roll (rolling roll having a hologram relief pattern), which saves the effort of cleaning the roll.

Another method of forming a hologram relief pattern will be explained based on FIG.

As shown in FIG. 2A, a photoresist layer 11 is formed by applying photoresist ink to the surface of the aluminum foil 10. As shown in FIG. The thickness of this photoresist layer 11 is preferably in the range of 0.1 to 1 μm. This is because if it is outside this range, it will be difficult to form a relief pattern made of an anodic oxide film, which will be described later. The coating method may be any of spin coating, spray coating, wiper blade method, etc.

An image of a hologram relief pattern is printed onto the photoresist layer 11. The baking means is
A method using a well-known laser beam to interfere with an object wave and a reference wave, or a method using an ultraviolet lamp to print on a mask on which a hologram fine line pattern has been previously recorded can be adopted.

After the above-mentioned printing, development is performed. In this development process, the photoresist layer 11 is formed as shown in FIG.
The more strongly exposed the portion is, the more it melts, and the surface of the underlying aluminum foil 10 is exposed. In weakly exposed areas, the surface of the aluminum foil 10 is not exposed, and the resist layer 1 is thinly exposed.
1 remains. Thereafter, the resist layer 11 is cured by known means. And when this is anodized,
2 (Fig.
An anodized film 12 (alumina) as shown in c) is formed, grows from the surface of the aluminum foil 10, and protrudes upward. Thereafter, the resist layer 11 is removed with a remover, and as shown in FIG. 2(d), an aluminum foil 10 is obtained in which a hologram relief pattern of an anodic oxide film 12 with good contrast is formed. Furthermore, if necessary, dry etching such as ion etching may be performed to improve the contrast or to make the surface of the film 12 harder.

The anodic oxide film 12 is made of sulfuric acid, phosphoric acid,
It may be a porous or barrier film formed in a solution of oxalic acid, chromic acid, boric acid, ammonium borate, or the like. Its thickness is 0.05-1μ, preferably
It is 0.1-0.3μ.

In addition to the methods described above, a drawing die, for example, can be used to provide a hologram relief pattern on a three-dimensional object such as a container. An example of this method is shown in FIGS. 3 and 4. As shown in the figure, a molded cup 21 made of a sheet made of aluminum foil with a synthetic resin film bonded to the inner surface is fitted onto the tip of the mandrel 20, and a ring-shaped drawing die 22 is press-fitted onto the outer periphery of the molded cup 21. On the inner periphery of this drawing die 22, a fine linear negative relief pattern 23 (for example, line spacing 0.
By ironing with this die 22, a hologram relief pattern 24 is formed on the surface of the aluminum foil, so that the surface of the cup 21 exhibits an interference color.

More detailed experimental examples will be given below.

[Experimental Example 1] First, a hologram relief pattern (negative) was formed on a stainless steel foil having a thickness of 30 μm and having excellent surface gloss by photoresist, image printing using an interference method, and ion etching. The obtained foil was wound around one of the rolling rolls of a two-high rolling mill, the jack pressure was set to about 20 kg/cm, and a mirror-finished hard aluminum foil (1N30) with a thickness of 50 μm was passed once between the rolls for a skin pass. The obtained aluminum foil has a hologram relief pattern similar to that formed on stainless steel foil (approximately 1,500 lines/mm, difference in unevenness of approximately 0.5 mm), which was found by cross-sectional observation using a scanning electron microscope.
1μ).

[Experimental Example 2] A hologram relief pattern was formed directly on one aluminum rolling roll of a two-high rolling mill, and approximately 20% of the aluminum foil used in Experimental Example 1 was used.
Cold rolling was performed at a rolling reduction ratio of .

The aluminum foil obtained had a holographic relief pattern similar to that of a rolling roll.

[Experimental Example 3] First, photoresist ink (Shipley 1350, Shipley
y Company Inc. ) was spin-coated to form a photoresist layer approximately 0.7μ thick, and then argon laser (488 nm, Spectra-Phys
lcs Model 165) was used to record the interference pattern of the object wave and reference wave on the photoresist layer, and then a developer (Microposit MF-312, Sh
ipley Company Inc. ) was used to form a relief pattern with a line width of about 0.5 μm and a difference in unevenness of about 0.2 μm.

Thereafter, anodization treatment was carried out at room temperature in 15% by weight sulfuric acid at a constant DC voltage so that the oxide film thickness became 0.2 μm, and the remaining photoresist layer was removed in a photoresist remover solution.

The relief pattern of the anodic oxide film obtained had a hologram pattern.

[Experimental Example 4] A photoresist layer was formed on the same aluminum foil as in Experimental Example 3, a mask glass slide on which a fine hologram pattern was recorded was placed on top of the photoresist layer, and the fine pattern was transferred by irradiating ultraviolet rays. . Next, using the same developer as in Experimental Example 3, a relief pattern with a density of 2500 lines/mm and a difference in unevenness of about 0.2 μm was formed. Thereafter, anodization was performed at room temperature in 5% by weight oxalic acid at a constant DC voltage so that the oxide film thickness became 0.3 μm, and the remaining photoresist layer was removed using a remover solution.

The relief pattern of the anodic oxide film obtained had a hologram pattern.

[0032]

[Effects] According to the present invention, as described above, since an integral hologram relief pattern is provided on the surface of the aluminum foil, a product with excellent heat resistance and abrasion resistance can be obtained. Since the hologram relief pattern was formed by anodic oxidation after printing using the photoresist method, a high-resolution relief pattern on the order of 1500 lines/mm, which was impossible with the conventional hot stamping method, could be reproduced extremely easily and at low cost. I can do it.

[Brief explanation of the drawing]

[Figure 1] Cross-sectional view showing the process of forming a hologram relief pattern on metal foil

[Figure 2] Cross-sectional view showing the process of forming a hologram relief pattern on the surface of aluminum foil

[Figure 3] A perspective view showing the process of forming a hologram relief pattern on the surface of an aluminum container.

[Figure 4] Partially enlarged cross-sectional view of the drawing die used in the above process

[Explanation of symbols]

1 Metal foil 2 Photoresist layer 3 Ecchi pit 10 Aluminum foil 11 Photoresist layer 12 Anodic oxide film 20 Mandrel 21 Molded cup 22 Drawing die 23 Negative relief pattern 24 Hologram relief pattern

Claims (3)

[Claims] Claim: 1. An aluminum foil having a hologram relief pattern integrally formed on its surface. 2. Aluminum having a hologram relief pattern, which is obtained by cold rolling an aluminum foil using a rolling mill with a hologram relief pattern on a rolling roll, thereby transferring the hologram relief pattern onto the surface of the aluminum foil. Method of manufacturing foil. 3. A photoresist layer is formed on the surface of the aluminum foil, an image of a hologram relief pattern is printed by irradiation with ultraviolet rays or a laser beam, developed, and anodized, and then the remaining photoresist layer is removed. A method for producing an aluminum foil having a holographic relief pattern comprising: