JP2006016673A - Functional aluminum alloy sheet and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional aluminum alloy sheet whose adhesion and corrosion resistance can be improved more than those of the conventional one, and to provide its production method. <P>SOLUTION: The functional aluminum alloy sheet comprises: a substrate 10 composed of an aluminum alloy sheet; a chemical film 2 formed on one side or both sides of the substrate 10; and a resin coating film 3 formed after the application of corona discharge treatment from the surface of the chemical film 2. It is preferable that the resin coating film 3 is formed of epoxy resin, polyester resin or urethane resin, and has a thickness of 1 to 150 μm. The chemical film 2 is preferably composed of phosphoric acid chromate, zirconium phosphate, zirconium oxide or chromic acid chromate, wherein the coating amount is 5-40 mg/m<SP>2</SP>. The functional aluminum alloy sheet is preferably the stock for a can top worked into the cover of a drink can. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a functional aluminum alloy plate (including an aluminum alloy foil) excellent in adhesion and corrosion resistance.

  Conventionally, so-called functional aluminum alloy plates, such as a coating material in which the surface of an aluminum alloy plate is coated with a resin coating film, or a laminate material in which a resin film is attached to the surface of an aluminum alloy plate, have been widely used. These functional aluminum alloy plates can exhibit excellent corrosion resistance and design properties while maintaining the workability and excellent strength characteristics of the aluminum alloy plates.

As the functional aluminum alloy plate, a surface treatment of coating or laminating is performed on a flat plate material in advance, and then a pre-processing material that is subjected to bending or the like, and a flat plate material is subjected to bending or the like It is roughly divided into post-processing materials for surface treatment of coating or laminate. And these are used properly according to the kind and use.
Since the post-treated material is subjected to a surface treatment after processing, the degree of processing is not limited, and has been used for various purposes. On the other hand, the pre-processed material is limited in processability to some extent, but coupled with recent progress in processability improvement technology, it also specializes in process rationalization, cost reduction, etc. It has become widely used as a material for home appliances, OA equipment casings, and building materials.

Regardless of whether it is a post-treatment material or a pre-treatment material, generally, the basic properties required for a functional aluminum alloy plate include adhesion between the aluminum alloy plate material and a coating film or a resin film, and corrosion resistance. is there. For this reason, since the aluminum alloy plate manufactured by rolling is soiled with rolling oil or the like, first, a degreasing treatment using a weak alkaline degreasing liquid or a solvent is performed. Thereafter, in order to ensure adhesion, the surface of the plate is etched, and in some cases, after pickling treatment for the purpose of desmutting, a chemical conversion film is formed by chemical conversion treatment. As the chemical conversion treatment, a phosphoric acid chromate chemical conversion treatment that is excellent in adhesion, corrosion resistance, cost, and the like is common. On top of that, a pre-coating material (pre-processing material) is a resin coating film formed without being processed. Further, the post-coating material (post-processing material) is formed by performing the above-mentioned chemical conversion treatment after processing, or processing after the chemical conversion treatment, and then forming a resin coating film.
Similarly, a pre-laminated material (pre-processed material) is obtained by bonding a resin film on a chemical conversion film without any processing. On the other hand, the above-mentioned chemical conversion treatment is performed after processing, and then the resin film is bonded. What is obtained is a post-laminate material (post-processing material).

Recently, there has been a strong demand for higher functionality and cost reduction of the final product, and environmental improvement, and the demand for functional aluminum alloy sheets is increasing. Further, in both the post-processing material and the pre-processing material, further improvement in the adhesion between the aluminum alloy plate serving as the substrate and the surface treatment film such as a coating film or a resin film is desired. In particular, the blurring treatment material is required to have excellent adhesion that can withstand subsequent processing.
In addition, as a literature regarding the functional aluminum alloy plate proposed so far, there are the following.

JP 2000-280399 A JP 2000-281118 A JP 2001-179881 A JP 2002-206178 A

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a functional aluminum alloy plate capable of improving adhesion and corrosion resistance as compared with the conventional one and a method for producing the same.

A first invention is a substrate made of an aluminum alloy plate;
A chemical conversion film formed on one or both sides of the substrate;
A functional aluminum alloy plate having a resin coating film formed after corona discharge treatment from the surface of the chemical conversion coating film (Claim 1).

The most remarkable point in the functional aluminum alloy sheet of the present invention is that, as described above, the resin coating film is formed after the corona discharge treatment is performed from the surface of the chemical conversion coating. Here, in the corona discharge treatment, a high voltage is momentarily applied between the electrodes installed in the air to break through the air insulation and instantaneously discharge the material to be treated (electrons collide with the surface of the substrate). ) Processing.
The functional aluminum alloy plate of the present invention is an unprecedented method in which the chemical conversion film as the first base treatment is formed on the substrate, and then the corona discharge treatment is performed as the second base treatment. It was obtained through active adoption.

Therefore, the said functional aluminum alloy plate can aim at the improvement of the adhesiveness of a resin coating film and a board | substrate, and the corrosion resistance of a board | substrate rather than what formed the resin coating film immediately after the conventional chemical conversion film formation.
And the improvement of the use of the said functional aluminum alloy plate and quality, such as workability, can further be improved by the improvement of this adhesiveness and corrosion resistance.
The mechanism by which such effects can be obtained has not yet been clarified structurally, but by performing the corona discharge treatment after the formation of the conversion coating, the micro-soil content in the conversion coating can be decomposed and removed. It is presumed that the above effect can be obtained because the adhesion improving effect by the chemical conversion film can be maximized.

  The above-described effects are effective in both the so-called post-coating material and the pre-coating material, but the pre-coating material can increase the degree of freedom of subsequent processing in particular. It is valid.

  2nd invention is the adhesive layer which consists of the board | substrate which consists of an aluminum alloy plate, the chemical conversion film formed in the single side | surface or both surfaces of this board | substrate, and the adhesive apply | coated after performing a corona discharge process from the surface of this chemical conversion film And a functional aluminum alloy plate characterized by having a resin film joined by the adhesive layer.

  The most notable point in the functional aluminum alloy plate of the present invention is that, as described above, the resin film is bonded through the adhesive layer applied after the corona discharge treatment from the surface of the chemical conversion film. . That is, the functional aluminum alloy plate of the present invention is an unprecedented method in which the chemical conversion film is formed on the substrate as the first base treatment, and then the corona discharge treatment is performed as the second base treatment. It was obtained through active adoption.

Therefore, the functional aluminum alloy plate is intended to improve the adhesion between the resin film and the substrate and the corrosion resistance of the substrate, compared to the case where the resin film is bonded via the adhesive layer after the conventional chemical conversion film is formed. Can do.
And the improvement of the use of the said functional aluminum alloy plate and quality, such as workability, can further be improved by the improvement of this adhesiveness and corrosion resistance. In addition, it is thought that the reason for obtaining this action effect is the same as in the case of the coating material.
The above-described effects are effective for both so-called post-laminating materials and pre-laminating materials, but the pre-laminating material increases the degree of freedom of subsequent processing as in the case of the coating material. It is more effective because it can.

Next, there is the following invention as an invention of a method for producing the functional aluminum alloy plate of the first invention.
That is, as a third invention, a chemical conversion treatment step of forming a chemical conversion film on one side or both sides of a substrate made of a degreased aluminum alloy plate, and a corona discharge step of performing a corona discharge treatment from the surface of the chemical conversion coating, And a coating step of forming a resin coating film on the chemical conversion film that has been subjected to the corona discharge treatment (Claim 7).

  In the manufacturing method of the present invention, as described above, the second base treatment step called the corona discharge step is subsequently performed following the first base treatment step called the chemical conversion treatment step. By carrying out these two continuous surface treatment steps, the adhesion between the resin coating film formed in the subsequent coating step and the substrate can be improved as compared with the conventional, and the above-described excellent functional aluminum alloy A board can be obtained.

  In addition, before performing the said chemical conversion treatment process, plastic processing is added to the said board | substrate, and the said chemical conversion treatment process, a corona discharge process, and a coating process can also be performed after that. In this case, a post coat material is obtained. Moreover, what was produced without performing the said plastic working becomes a precoat material.

Moreover, there exists the following invention as invention of the method of manufacturing the functional aluminum alloy plate of the said 2nd invention.
That is, as a fourth invention, a chemical conversion treatment step of forming a chemical conversion film on one side or both sides of a substrate made of a degreased aluminum alloy plate, a corona discharge step of performing a corona discharge treatment from the surface of the chemical conversion coating, It has the adhesive application process which forms the adhesive bond layer which consists of an adhesive agent on the said chemical conversion film which performed the said corona discharge process, and the film joining process which joins a resin film on the said adhesive bond layer, It is characterized by the above-mentioned. There is a method for producing a functional aluminum alloy sheet (claim 9).

  Also in the manufacturing method of the present invention, as described above, the second base treatment step called the corona discharge step is subsequently performed following the first base treatment step called the chemical conversion treatment step. By carrying out these two continuous surface treatment steps, the adhesiveness between the resin film and the substrate disposed in the subsequent adhesive coating step and the film bonding step can be improved as compared with the prior art. An excellent functional aluminum alloy plate can be obtained.

  In addition, before performing the said chemical conversion treatment process, plastic processing is added to the said board | substrate, and the said chemical conversion treatment process, a corona discharge process, an adhesive agent coating process, and a film joining process can also be performed after that. In this case, a post-laminate material is obtained. Moreover, what was produced without performing the said plastic working becomes a pre-laminate.

  In the first and third inventions, the resin coating film is made of any one of an epoxy resin, a polyester resin, and a urethane resin, and preferably has a thickness of 1 to 150 μm. 8). When these synthetic resins are employed as the resin coating film, the effect of improving the adhesion can be reliably obtained. Further, when the thickness of the resin coating film is less than 1 μm, there are problems that the corrosion resistance and scratch resistance are deteriorated and it is difficult to ensure the mass production stability. There are problems such as poor film adhesion and difficulty in realizing mass production coating by roll coating.

  Moreover, in the said 2nd and 4th invention, while the said resin film consists of either polyethylene terephthalate, nylon, polyester, a polypropylene, and a vinyl chloride, it is preferable that the thickness is 1-150 micrometers. Item 4, 10). When these synthetic resins are employed as the resin film, it is possible to surely obtain the effect of improving the adhesion. Further, when the thickness of the resin film is less than 1 μm, there is a problem that the corrosion resistance is lowered. On the other hand, when the thickness exceeds 150 μm, there is a problem that the cost becomes too high.

In the functional aluminum alloy plate of the first and second inventions, the chemical conversion film is any one of phosphate chromate, zirconium phosphate, zirconium oxide, or chromate chromate having a coating amount of 5 to 40 mg / m ^2. (Claim 5)
In the production methods of the third and fourth inventions, in the chemical conversion treatment step, any one of phosphate chromate, zirconium phosphate, zirconium oxide, or chromate chromate having a coating amount of 5 to 40 mg / m ² is used. It is preferable to form the chemical conversion film.

The above-mentioned phosphate chromate, zirconium phosphate, zirconium oxide, or chromate chromate are all excellent chemical conversion films as a base treatment for aluminum alloys, and their characteristics can be further improved by combination with the corona discharge treatment. . When the amount of the chemical conversion film is less than 5 mg / m ² , there is a problem that adhesion and corrosion resistance are lowered. On the other hand, when it exceeds 40 mg / m ² , there is a problem that the cost becomes too high.

In the corona discharge process, it is preferable to perform the corona discharge treatment under the conditions of an output of 0.00002 to 1.0 kWh / m ² and a distance between electrodes of 0.1 to 5 mm. To perform corona discharge, a high potential is applied to an electrode disposed opposite to an aluminum alloy plate (substrate) connected to the ground. The output can be specifically expressed by the electric power applied to the electrode. However, in actuality, since the substrate is processed while relatively running, the output unit is kWH / m ² . . When this is less than 0.00002 kWh / m ² , there is a problem that adhesion and corrosion resistance are lowered, while when it exceeds 1.0 kWh / m ² , there is a problem that the cost is increased. The inter-electrode distance is the distance between the electrode and the aluminum alloy plate. When this distance is less than 0.1 mm, there is a problem that it is difficult to produce industrially stable, while 5 mm In the case of exceeding, there is a problem that corona discharge cannot be uniformly supplied to the plate surface.

  Moreover, it is preferable that the said functional aluminum alloy board is a raw material for can lids processed into the lid | cover of a drink can (Claims 6 and 13). The lid of a beverage can is one of the applications in which a functional aluminum alloy plate is widely used. Especially for beverages, the lid can adhere to the adhesion between the substrate and the resin coating film or the resin molded film, and the corrosion resistance of the substrate. The demand is severe. Therefore, it is very effective to use the effect of improving the adhesion and corrosion resistance by the corona discharge treatment.

A functional aluminum alloy plate according to an embodiment of the present invention will be described with reference to FIGS.
In this example, functional aluminum alloy plates as a plurality of examples and comparative examples were produced and their characteristics were evaluated.

Example 1
As shown in FIG. 1, the functional aluminum alloy plate 1 of Example 1 is subjected to corona discharge treatment from a substrate 10 made of an aluminum alloy plate, a chemical conversion film 2 formed on one surface of the substrate 10, and the surface of the chemical conversion film 2. It has the resin coating film 3 formed after giving.
In producing the functional aluminum alloy plate 1, first, an aluminum alloy plate having a thickness of 0.5 mm and a material 5052-H34 was prepared as the substrate 10. And the degreasing process of this board | substrate was performed.
In the degreasing treatment, sodium carbonate and caustic soda-based fine cleaner E3001 manufactured by Japan Parker Rising were adjusted with pure water to 15 g / L, and the substrate was immersed in a treatment solution heated to 60 ° C. for 5 seconds. .

Next, the chemical conversion treatment process which forms a chemical conversion film in the single side | surface of the board | substrate which performed the said degreasing process was performed. In Example 1, a film was formed by phosphoric acid chromate treatment.
The phosphoric acid chromate treatment was performed by degreasing the substrate with an alkaline degreasing agent and then immersing it in a phosphoric acid chromate treatment bath. The chromate film amount was 20 ± 5 mg / m ² as the Cr content in the film.

Next, the corona discharge process which performs a corona discharge process from the surface of the said chemical conversion film was performed.
Corona discharge treatment uses an electrode having a length of 300 mm, output: 0.011 kWH / m ² (actually, the output of the apparatus is 1 kW, the relative movement of the substrate is 5 m / min), and the distance between the electrodes is 5 mm. Performed under conditions.

Next, immediately after the corona discharge treatment, a coating process for forming a resin coating film on the chemical conversion film was performed.
Specifically, a commercially available water-soluble epoxy acrylic resin is applied to the chemical conversion film on one surface of the substrate using a bar coater, and the temperature of the aluminum surface is maintained at 230 ° C. for 60 seconds. Thus, a 50 μm thick resin coating film was formed by baking and curing.

(Comparative Example 1)
In Comparative Example 1, the corona discharge treatment step in Example 1 was omitted, and the others were produced in the same manner as in Example 1.

(Example 2)
In Example 2, the chemical conversion treatment step in Example 1 was changed to a non-chromium chemical conversion treatment, and the others were produced in the same manner as in Example 1.
Specifically, the non-chromium chemical conversion treatment in this case was performed by immersing the degreased substrate in a zirconium phosphate bath. The amount of chemical conversion film was 15 mg / m ^{2 in} terms of Zr content.

(Comparative Example 2)
In Comparative Example 2, the corona discharge treatment step in Example 2 was omitted, and the others were produced in the same manner as in Example 2.

Example 3
As shown in FIG. 2, the functional aluminum alloy plate 5 of Example 3 is subjected to corona discharge treatment from a substrate 50 made of an aluminum alloy plate, a chemical conversion film 6 formed on one surface of the substrate 50, and the surface of the chemical conversion film 6. It has the adhesive layer 7 which consists of an adhesive apply | coated after this, and the resin film 8 joined by the adhesive layer 7. FIG.

In producing the functional aluminum alloy plate 5, as in Example 1, the substrate was subjected to the degreasing treatment, the chemical conversion treatment step and the corona discharge step, and then immediately after the corona discharge treatment was performed on the chemical conversion film. An adhesive coating process for forming an adhesive layer made of an adhesive and a film bonding process for bonding a resin film on the adhesive layer were performed.
More specifically, in the adhesive application step, 1 g / m ² of urethane adhesive was applied as an adhesive, and thereafter, in the film bonding step, a commercially available nylon film having a thickness of 20 μm was laminated.

(Comparative Example 3)
In Comparative Example 3, the corona discharge treatment step in Example 3 was omitted, and the others were produced in the same manner as in Example 3.

Example 4
Example 4 is an example in which the resin film in Example 3 was changed to a polypropylene film with a thickness of 25 μm, and the others were the same as Example 3.
(Comparative Example 4)
In Comparative Example 4, the corona discharge treatment step in Example 4 was omitted, and the others were produced in the same manner as in Example 4.

(Example 5)
Example 5 is an example in which only the conditions of the corona discharge treatment in Example 1 were changed, and the others were the same as Example 1.
The corona discharge treatment in Example 5 is performed under the condition that the output is 0.00002 kW / m ² (actually, the output of the apparatus is 0.02 kW, the relative movement of the substrate is 60 m / min), and the distance between the electrodes is 5 mm. Others were the same as in Example 1.

(Comparative Example 5)
In Comparative Example 5, the corona discharge treatment conditions in Example 5 were further changed, and the output was 0.00001 kW / m ² (actually, the output of the apparatus was 0.01 kW, and the relative movement of the substrate was 60 m / min. This is an example in which the distance between the electrodes is 1 mm, and the others are the same as in the fifth embodiment.

(Example 6)
Example 6 is an example in which only the conditions of the corona discharge treatment in Example 1 were changed, and the others were the same as Example 1.
In the corona discharge treatment in Example 6, the output is 1 kWh / m ² (actually, the output of the apparatus is 2 kW, the relative movement of the substrate is 0.1 m / min), and the distance between the electrodes is 5 mm. Others were the same as in Example 1.

(Comparative Example 6)
In Comparative Example 6, the conditions of the corona discharge treatment in Example 6 were further changed to output: ² kWH / m ² (actually, the output of the apparatus was 2 kW, and the relative movement of the substrate was 0.05 m / min. ), And the distance between the electrodes is 5 mm, and the others are the same as in Example 6.

(Example 7)
In Example 7, the distance between the electrodes in Example 1 was set to 0.1 mm, and the others were produced in the same manner as in Example 1.
(Comparative Examples 7 and 8)
In Comparative Example 7 and Comparative Example 8, the distances between the electrodes in Example 1 were set to 0.05 mm and 7 mm, respectively.

Next, the functional aluminum alloy plates of the above examples and comparative examples were evaluated. The evaluation method was as follows.
<Adhesion evaluation>
For adhesion, JIS K5400 8.5.2 cross cut tape method was used, and the peeling of the coating film after spraying with salt water for 500 hours was investigated. As evaluation criteria, 95 or more remaining coatings after the above test were indicated as と し て, and less than 95 points were indicated as x, indicating failure.

<Corrosion resistance evaluation>
Corrosion resistance was evaluated by using JIS K54009.1 salt spray resistance and initially observing the corrosion state after 500 hours. The evaluation criteria were indicated by “◎” when the corrosion width of the cross-cut portion of the coating film was 3 mm or less as acceptable, and “x” when the corrosion width exceeded 3 mm was rejected.

<Manufacturing cost>
Manufacturing cost is evaluated by corona discharge amount of power supply, ◎ as the best in the case of less than 0.001kWH / m ^2, ○ as good in the case of ^{0.001~1.0kWH / m 2, 1.0kWH / m} 2 If it exceeds, it is shown as x as bad.
All the results are shown in Table 1.

  As is known from Table 1, by performing a corona discharge treatment after the chemical conversion treatment, the adhesion between the resin coating film or the resin film and the substrate on the functional aluminum alloy plate can be improved, and as a result, the corrosion resistance can also be improved. it can. Then, it is possible to increase the accuracy of the processing thereafter by the factory for adhesion and the like.

Further, from the comparison between Examples 5 and 6 and Comparative Examples 5 and 6, it is preferable that the condition for performing the corona discharge treatment is at least the output in the range of 0.00002 to 1.0 kWh / m ^2. Recognize.

Explanatory drawing which shows the structure of the functional aluminum alloy plate in Example 1. FIG. Explanatory drawing which shows the structure of the functional aluminum alloy plate in Example 3. FIG.

Explanation of symbols

1, 5 Functional aluminum alloy plate 10, 50 Substrate 2, 6 Chemical conversion coating 3 Resin coating 7 Adhesive layer 8 Resin film

Claims (13)

A substrate made of an aluminum alloy plate;
A chemical conversion film formed on one or both sides of the substrate;
A functional aluminum alloy plate comprising a resin coating film formed after corona discharge treatment from the surface of the chemical conversion coating.   2. The functional aluminum alloy plate according to claim 1, wherein the resin coating film is made of any one of an epoxy resin, a polyester resin, and a urethane resin and has a thickness of 1 to 150 [mu] m. A substrate made of an aluminum alloy plate;
A chemical conversion film formed on one or both sides of the substrate;
An adhesive layer made of an adhesive applied after the corona discharge treatment from the surface of the chemical film;
A functional aluminum alloy plate comprising a resin film bonded by the adhesive layer.   4. The functional aluminum alloy plate according to claim 3, wherein the resin film is made of any one of polyethylene terephthalate, nylon, polyester, polypropylene, and vinyl chloride, and has a thickness of 1 to 150 [mu] m. 5. The chemical conversion film according to claim 1, wherein the chemical conversion film is any one of phosphate chromate, zirconium phosphate, zirconium oxide, or chromate chromate having a coating amount of 5 to 40 mg / m ^2. Functional aluminum alloy plate.   The functional aluminum alloy plate according to any one of claims 1 to 5, wherein the functional aluminum alloy plate is a material for a can lid that is processed into a lid of a beverage can. A chemical conversion treatment step of forming a chemical conversion film on one or both sides of a substrate made of an aluminum alloy plate subjected to degreasing;
A corona discharge process for performing a corona discharge treatment from the surface of the chemical conversion film;
And a coating process for forming a resin coating film on the chemical conversion film subjected to the corona discharge treatment.   8. The method for producing a functional aluminum alloy plate according to claim 7, wherein the resin coating film is made of any one of an epoxy resin, a polyester resin, and a urethane resin and has a thickness of 1 to 150 μm. . A chemical conversion treatment step of forming a chemical conversion film on one or both sides of a substrate made of an aluminum alloy plate subjected to degreasing;
A corona discharge process for performing a corona discharge treatment from the surface of the chemical conversion film;
An adhesive application step of forming an adhesive layer made of an adhesive on the chemical conversion film subjected to the corona discharge treatment;
A method for producing a functional aluminum alloy plate, comprising: a film joining step for joining a resin film on the adhesive layer.   10. The method for producing a functional aluminum alloy plate according to claim 9, wherein the resin film is made of any one of polyethylene terephthalate, nylon, polyester, polypropylene, and vinyl chloride and has a thickness of 1 to 150 μm. . In any one of claims 7 to 10, in the chemical conversion treatment step, phosphoric acid chromate coating weight of 5 to 40 mg / m ^2, zirconium phosphate, zirconium oxide, or more becomes the chemical conversion either chromic acid chromate A method for producing a functional aluminum alloy sheet, wherein a film is formed. The corona discharge process according to any one of claims 7 to 11, wherein in the corona discharge step, corona discharge treatment is performed under conditions of an output of 0.00002 to 1.0 kWh / m ² and a distance between electrodes of 0.1 to 5 mm. A method for producing a functional aluminum alloy sheet.   The method for producing a functional aluminum alloy plate according to any one of claims 7 to 12, wherein the functional aluminum alloy plate is a material for a can lid that is processed into a lid of a beverage can.

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