JPH01162800A - Aluminum cap material having superior adhesion of printing ink - Google Patents

Abstract

PURPOSE:To produce an Al cap material having superior adhesion of printing ink when an Al sheet is subjected to external printing, by forming an oxide film of a specified thickness by anodic oxidation with phosphoric acid before the printing. CONSTITUTION:When the surface of an Al sheet corresponding to the outside of a cap is subjected to prescribed external printing to produce an Al cap material, an oxide film of 0.05-0.5mum thickness is formed by anodic oxidation with phosphoric acid before the printing. A phosphoric acid bath having 60-345g/l concn. of phosphoric acid is preferably used and anodic oxidation is carried out at 40-75 deg.C bath temp. and 5-45A/dm<2> anode current density for <15sec. An Al cap material having superior adhesion of printing ink is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to capping materials for bottles, bottles, etc., and particularly to an aluminum capping material that has excellent adhesion to printing ink.

(Prior art and its problems) Aluminum cap materials have traditionally been widely used in deep drawing processing, and are recognized as materials with good deep drawing workability, and are advantageously used as cap materials for bottles, bottles, etc. It is being Prior to deep drawing, such aluminum cap material is generally subjected to printing or painting on its inner and outer surfaces, and such operations include (a) inner/outer surface size coating, (bl In reality, the processes of applying gold varnish on the inner surface, (C) printing on the outer surface, and (d) top clear coating on the outer surface are performed in order.

However, when printing the external surface of such an aluminum cap material, in addition to being deep drawn after printing, such an external surface is a very important part in terms of decoration, display function, etc. Since then, strict requirements have been placed on printing characteristics, but conventional size coat
In the products obtained through the printing process, there is still room for improvement in terms of the adhesion of the printing layer.For example, in the case of ultra-deep drawing cap materials, the adhesion of the printing ink is insufficient. In particular, it has been recognized that those printed with sumi ink have inherent problems such as peeling phenomenon and insufficient blackness. This problem can be solved by boiling aluminum cap products that have been molded after black printing.
When subjected to an accelerated deterioration test such as immersion in hot dilute sulfuric acid, a negative layer becomes apparent.

In addition, the current size coating applied to the aluminum cap material prior to external printing is usually done in a sheet-fed manner using a cutting plate that is applied to a coating machine, which results in poor productivity. This was also one of the reasons why processing costs soared.

(Solution Means) Here, the present invention has been made against the background of the above, and its feature is that a predetermined outer surface printing is applied to the surface of the aluminum plate material that becomes the outer surface of the cap. In this aluminum cap material, a phosphoric acid anodic oxide film with a thickness of 0.05 to 0.5 μm is provided as a base for such external printing.

That is, the present invention provides an aluminum cap material by subjecting an aluminum plate material to the above-described surface treatment and then printing a predetermined outer surface thereon, instead of the conventional outer surface size coating. It has been designed to provide excellent adhesion to metal printing inks, especially sumi ink, and it has also been made possible to process with a coil, making the processing cost at least lower than the current size coat. be.

(Specific structure) By the way, as the aluminum plate material to which the present invention is applied, any aluminum plate-like material conventionally used as a cap material is applicable, and the material and preparation There are no restrictions on quality, plate thickness, etc.

In addition, before the aluminum plate material is subjected to the surface treatment according to the present invention, it is generally subjected to a degreasing treatment as a pretreatment, but this degreasing treatment is performed using an acidic degreasing agent. There is no problem whether it is an alkaline degreasing agent, a weak to medium/strong etching agent, or even a combination of these. It goes without saying that other means can be used as long as the surface of the surface is kept clean.

In the present invention, the surface of such an aluminum plate material is subjected to phosphoric acid anodic oxidation treatment as a base treatment for external printing, so that the phosphoric acid anodic oxidation film as the base film has a thickness of 0.05 to A film thickness of 0.5 μm is formed on the surface of the plate.

In this way, on the surface of such aluminum plate,
By applying phosphoric acid anodic oxidation treatment in place of the conventional nozzle surface size coating, the adhesion of metal printing ink printed on the surface can be significantly improved, and the effect is particularly great for sumi ink. It becomes.

Note that if the oxide film is too thin, that is, 0.
Needless to say, if the thickness is less than 0.5 μm, the adhesion of the ink formed thereon will not be sufficient. Even in such cases, a sufficient improvement in ink adhesion cannot be expected.

By the way, the formation of such a phosphoric acid anodic oxide film generally involves the following steps:
This will be done in a coiled state.

In other words, aluminum cap materials in particular are mainly semi-rigid materials with a thickness of a < (about 0.25 mm), so the single-wafer method of anodizing in conventional size coats is rather inefficient. However, by employing such phosphoric acid anodization treatment, the printing base treatment can be advantageously performed in the coil state, and the cost of printing base treatment can be advantageously reduced. It is.

In addition, when forming a phosphoric acid anodic oxide film as described above, preferably the phosphoric acid concentration is 60 to 3.
Using a 45 g/j2 phosphoric acid bath, bath temperature 40-75°C,
An anodic oxidation method is suitably employed under the conditions of anode current density: 5 to 45 A/dm'' and an electrolytic time not exceeding 15 seconds.

In addition, in such anodic oxidation treatment, if the phosphoric acid concentration in the phosphoric acid bath falls outside the above-mentioned concentration range, it becomes difficult to obtain an oxide film with excellent characteristics. In other words, when the phosphoric acid concentration exceeds 345 g/j2, the adhesion of the ink tends to decrease;
/ If it is less than 1, the electrolysis time will be long and it will be difficult to process the coil. Furthermore, if the bath temperature exceeds 75°C, it becomes difficult to obtain an oxide film with excellent ink adhesion, and if the bath temperature is below 40°C, the electrolysis time becomes longer. . Furthermore, regarding the anode current density, it is 45
If it exceeds "A/dm", a large amount of hydrogen will be generated and the liquid temperature will rise, making the anodizing process difficult.
Moreover, if it becomes smaller than 5 A/dm2, a problem arises in that the electrolysis time becomes longer.

However, in the present invention, it is only necessary to form a phosphoric acid anodic oxide film with a film thickness of 0.05 to 0.5 μm on the surface of the aluminum plate, and the processing conditions are limited to the above conditions. It's definitely not a thing.

Next, this phosphoric acid anodic oxide film has a thickness of 0605 to 0.5 μm.
The aluminum plate formed with a film thickness of By drawing, it becomes the desired cap product. Note that the inner surface of such an aluminum plate material is also coated with ordinary gold varnish before or after the outer surface is printed.

(Effect of the invention) As described above, according to the present invention, as a base for external printing,
According to the aluminum cap material provided with a phosphoric acid anodic oxide film with a film thickness of 0.05 to 0.5 μm, ink adhesion is significantly improved compared to products obtained by the conventional size coat → printing process. By selecting a top clearer, it is possible to further enhance the effect of the present invention.Furthermore, the effect of the present invention is particularly noticeable when using Sumi ink. It becomes noticeable.

In addition, the base treatment applied to the aluminum cap material of the present invention is suitable for coil coating treatment,
Economically, it is cheaper than the current single-wafer size coating method, and its advantages are also great.

(Examples) Examples of the present invention are shown below to clarify the present invention more specifically, but the present invention is not limited in any way by the description of such examples. That goes without saying.

In addition to the following examples and the above-mentioned specific description, the present invention includes various changes and modifications based on the knowledge of those skilled in the art, as long as they do not depart from the spirit of the present invention. It should be understood that improvements and modifications may be made. Note that all percentages in the following examples are expressed on a weight basis unless otherwise specified.

First, American standard AA is often used as a cap material.
-Aluminum plate material equivalent to 8011-H14 (thickness:
A 3% aqueous solution of an alkaline degreaser: Ridrin 322N8 (manufactured by Nippon Paint Co., Ltd.) was applied to the aluminum plate material, while the coil was continuously taken out from the coil and run. After degreasing by spraying for 6 seconds at 0.degree. C., it was washed with water and dried.

Then, this degreased aluminum plate material was immediately anodized using an electrolytic bath consisting of an aqueous phosphoric acid solution under various conditions shown in Table 1 below.For comparison, A plate material (N[Lll) coated with a normal size coat was also prepared.

The various plate materials obtained in this way were used as test materials, and black printing was performed on the outer surface of each using a metal printing ink (MDC-94 manufactured by Toyo Ink Mfg. Co., Ltd.) according to a conventional method. (Number of prints: 2 times), and after that,
While a top coat was applied with an epoxy ester top clear (F69-IONA manufactured by Toyo Ink Manufacturing Co., Ltd.), gold varnish was applied to the inner surface of each plate.

Then, the thus obtained printed aluminum plate material was subjected to ultra-deep drawing in the same manner as before to form a cap product (height: 60mm, outer diameter: 30m+*).

The shape and name of the obtained cap molded product are as follows. First, a screw (thread cut) part is provided at a part 12 mm from the top surface (occlusion part) including the shoulder part, and a knurl (knurling, bead) part is provided at a length of 611 from this part of the screw. A skirt roller 1 and a skirt roller 2 of a predetermined depth are provided at a distance of 7 mm from the knurl and further 10 m from the knurl, and a skirt roller 1 and a skirt roller 2 of a predetermined depth are provided at a distance of 25 mm below the knurl. It is a molded cap with a body section.

Next, the cap molded products obtained by ultra-deep drawing in this way were immersed in spring water for 30 minutes for evaluation, and the appearance of each part of each molded product after boiling ( The state of ink peeling was visually determined and evaluated using a 5-point method.

Note that the higher the number of points, the worse the ink peeling condition becomes, and 1 point indicates the best appearance.

The results obtained are shown in Table 1. In addition, in the evaluation symbols in Table 1, ◎ indicates the best appearance, O indicates good, and △
indicates an acceptable appearance.

From the results in Table 1, regarding the peeling status of the body tape, the tape according to the present invention did not peel off at all, whereas the comparative example showed slight peeling, and the body tape did not peel off at all. Compared to the one according to the present invention, the gloss of the comparative example was lowered and the blackness was slightly faded.

And, as is clear from Table 1, according to the present invention,
The aluminum cap material, which has a phosphoric acid anodized film formed on the surface of the aluminum plate material as a base for external printing, exhibits excellent adhesion (formability) of the printed layer, thereby improving the quality of the cap. It has been recognized that the material can be advantageously obtained, and the effect of the present invention is as follows:
It exhibits excellent characteristics especially in printing using Sumi ink.

Applicant: Sumitomo Light Metal Industries, Ltd.

Claims (2)

[Claims] (1) The aluminum cap material is made by applying a predetermined outer surface printing to the surface of the aluminum plate material that becomes the outer surface of the cap, and as a base for such outer surface printing, 0.05 to 0.0
．． An aluminum cap material with excellent adhesion to printing ink, characterized by being provided with a 5 μm thick phosphoric acid anodic oxide film. (2) The phosphoric acid anodic oxide film is formed using a phosphoric acid bath within the range of phosphoric acid concentration: 60 to 345 g/l, bath temperature: 40 to 75°C, and anode current density: 5 to 45 A/dm^2,
The aluminum cap material according to claim 1, which is formed by anodizing for an electrolytic time not exceeding 15 seconds.