JPH0748677A - Aluminum di can and common surface treatment solution and process for tin di can - Google Patents

Abstract

PURPOSE:To obtain a film forming soln. for the aluminum DI can and tin DI can by specifying the composition of the soln. for treating the surface of the DI can before being coated and printed. CONSTITUTION:At least one kind between a zirconium compd. and a titanium compd. is added to phosphate ion to control the pH to 2.0-4.0. An oxidizing agent by <=500ppm and <=2000ppm of at least one kind between hydrofluoric acid and a fluoride as fluorine are added to obtain a surface-treating soln. The aluminum DI can and tin DI can degreased and washed with water are coated with a film. In this case, the can is previously treated with the surface- treating soln. by spraying or dipping at a room temp. to 50 deg.C for 2 to 120sec. Consequently, excellent corrosion resistance and coating adhesion are obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a DI can which is formed by drawing and ironing an aluminum plate and a tin-plated steel plate, and which has excellent corrosion resistance and coating on the surface of the can before being coated and printed. The present invention relates to a novel aluminum DI can and tin plating DI can both used as a surface treatment liquid and a treatment method for providing adhesion.

[0002]

2. Description of the Related Art Conventionally, aluminum DI tins and tin DI tins have been treated with a dedicated surface treatment liquid. Examples of the surface treatment liquid for aluminum DI can include those described in JP-A-52-131937. The surface treatment liquid disclosed in this publication contains zirconium or titanium or a mixture thereof, phosphate and fluoride, and has a pH of about 1.0.
˜4.0 acidic aqueous coating solution. When treatment is carried out using this chemical conversion treatment liquid, a chemical conversion film having zirconium or titanium oxide and phosphate as main components and having excellent corrosion resistance and coating adhesion is formed on the aluminum surface.

Examples of the surface treatment liquid for tinplate DI cans include those described in Japanese Patent Application Laid-Open No. 1-100281 proposed by the present applicant. This invention has a phosphate ion of 1 to 50 g / l and an oxygenate ion of 0.2 to 20.0 g.
/ L, 0.01 to 5.0 g / l of tin ions, 0.01 to 5.0 g / l of condensed phosphate ions, and a pH of 2 to 6, which is a chemical conversion solution for metal surface treatment. By treating with a liquid, a tin-based phosphate excellent in corrosion resistance can be formed on the surface of tinplate DI can.

By the way, the surface treatment equipment for DI cans is usually called a washer, and the molded DI cans are continuously treated with a degreasing liquid or a chemical conversion liquid in an inverted state. The existing washer is used for preliminary degreasing, degreasing, water washing, surface treatment,
It consists of 6 steps of washing with water and washing with deionized water.

When performing the surface treatment with the above-mentioned existing washer, the surface treatment liquid is appropriately selected depending on the type of DI can to be treated. That is, the surface treatment liquid for aluminum DI can is, for example, the above-mentioned JP-A-52-13193.
The treatment liquid according to the invention of No. 7 is used, and tinplate DI
As the treatment liquid for the can, for example, the treatment liquid according to the invention of JP-A-1-100281 described above is used.

[0006]

However, with the recent diversification of the production of DI cans, aluminum DI cans or tin-plated DI cans are batch-processed alternately to some extent in the same washer facility. The opportunities to do it are increasing. However, even if the treatment liquid of JP-A-52-131937 is applied to a DI can, a good coating excellent in corrosion resistance is not formed, and conversely, the treatment liquid of JP-A-1-100281 is applied to an aluminum DI can. Even if it is applied, a chemical conversion film is not formed, and there is a problem that the coating film adhesion and corrosion resistance are poor. For this reason, every time the object to be treated changes, it is matched with the object, the treatment liquid is discarded, the treatment tank is cleaned, and the treatment liquid is newly replaced.

In view of the above-mentioned present situation, the present invention is a combined treatment liquid and treatment capable of applying a coating having excellent corrosion resistance and coating adhesion to the surfaces of aluminum DI can and tin DI can with the same treatment liquid. It is intended to provide a method. The inventors of the present invention adversely affect the coating formed by the mixed metal ions, that is, aluminum and tin ions, on the surface of different types of objects, and this is the reason why a good coating is not formed even when the conventional treatment liquid is applied to different types of objects. The present invention has been completed by conducting further research.

[0008]

The present inventors have made clear that the following points are necessary to solve the above conventional problems. (1) Similar to the conventional treatment liquid, a film containing an oxide of zirconium or titanium as a main component is formed on the surface of an aluminum DI can. A film containing tin oxide as a main component is formed on the surface of the tin-plated DI can. (2) In order to form the film of the above (1), it is necessary to etch the target metal. Therefore, the pH of the treatment liquid is adjusted to 2.0 to 4.0. If the pH is less than 2.0, etching will increase and it will be difficult to form a film. If the pH exceeds 4.0, it will be difficult to form a film having excellent corrosion resistance. Therefore, the pH should be controlled in the range of 2.0-4.0. (3) Under the above condition (2), tin ions (Sn2 +, Sn4 +) are eluted from the surface of the tin-plated DI can. Tin ions eluted in the treatment liquid tend to be reduced to metallic tin on the surface during treatment of an aluminum can, which prevents formation of a good film on the aluminum surface. For this reason, it is necessary to add an oxidizing agent to the treatment liquid to rapidly oxidize tin ions in the treatment liquid to tetravalent so that the tin ions are stably present in the treatment liquid. (4) Also, under the above condition (2), aluminum ions are eluted from the aluminum surface. This aluminum ion interferes with the stability of the zirconium or titanium compound in the liquid. As a countermeasure against this, it is necessary to add hydrofluoric acid or fluoride to the treatment liquid so that aluminum can be stably present as fluoride in the treatment liquid. (5) The oxidizing agent promotes the formation of zirconium or titanium oxide on the aluminum surface, but tends to suppress the formation of phosphate. When the amount of the oxidizing agent exceeds 500 ppm, the formation of a film is hindered, so the upper limit is 500 ppm. If the amount of hydrofluoric acid and the amount of fluoride are too large, etching will be excessive and the appearance will be deteriorated. Therefore, the upper limit of 2000 ppm of fluorine is suitable.

The present invention has been completed by synthesizing the above-mentioned findings (1) to (5).
In a DI can treatment liquid containing a phosphate ion and at least one of a zirconium compound and a titanium compound and having a pH of 2.0 to 4.0, an oxidizing agent of 500 ppm or less and at least 1 of hydrofluoric acid and fluoride. A surface treatment liquid for aluminum DI cans and tin DI cans, which further contains 2000 ppm or less of fluorine as a seed.

Furthermore, the present invention relates to an aluminum DI can and a surface treatment method for a tin DI can, wherein the treatment liquid is brought into contact with an aluminum DI can or a tin DI can whose surface is clean.

Examples of the above-mentioned oxidizing agent include hydrogen peroxide, chlorate, nitrite, tungstate, molybdate, etc., but are not particularly limited, but hydrogen peroxide is preferable. Since the oxidizing agent has an effect of stabilizing tin eluted from the DI can, the optimum content thereof is selected according to the amount of tin eluted. Elution concentration of tin is 5
If it is about 0ppm, the content of oxidant is 20 ~ 500pp
A range of m is preferred. More preferable range is 40 to 20.
It is in the range of 0 ppm. In addition, when the stability of the treatment liquid is significantly lowered by metal ions such as iron or tin eluted from tin tin DI or aluminum eluted from aluminum DI can, an organic acid such as gluconic acid or oxalic acid is additionally added. You may add.

At least one of hydrofluoric acid (HF) and fluoride is contained in the treatment liquid. Hydrofluoric acid (HF), sodium fluoride (NaF
) Or fluorozirconic acid (H2ZrF)
6) or fluorotitanic acid (H2TiF6) or its salt can be used. The optimum content of fluoride is aluminum D
It is determined depending on the concentration of aluminum eluted from the can. Fluoride content is 10-2000pp as fluorine
The range of m is good, and the range of 20 to 90 ppm is particularly preferable. For example, the amount of fluorine required for 100 ppm of aluminum is about 200 ppm. If the fluoride content is less than 20 ppm in terms of fluorine, the reactivity of the treatment liquid with respect to the surface of the aluminum DI can is poor and a film cannot be formed sufficiently.

Other than the above-mentioned components, conventional processing liquids are known. Phosphoric acid (H3PO4), sodium phosphate (Na3PO4), or the like can be used to contain phosphate ions in the treatment liquid. The content is not particularly limited, but is preferably in the range of 10 to 500 ppm, particularly 20 to 9 ppm.
A range of 0 ppm is preferred.

In order to contain the zirconium and titanium compounds in the treatment liquid, zirconium and titanium oxides, hydroxides, fluorides and the like can be used without any particular limitation. The content of zirconium or titanium compound is 10 to 200 pp in terms of Zr or Ti.
The range of m is good, and the range of 30 to 800 ppm is particularly preferable.

The pH of the treatment liquid is adjusted by using an acid such as phosphoric acid, nitric acid, hydrochloric acid or hydrofluoric acid and an alkali such as sodium hydroxide, sodium carbonate or ammonium hydroxide. The pH range of the treatment liquid is 2.0 to 4.0. A more preferable pH range is 2.5 to 3.3.

Examples of the method for contacting the surface treatment liquid with the aluminum DI can and the tinned DI can include immersion treatment and spray treatment, but spray treatment is preferable. The temperature of the treatment liquid is, for example, room temperature to 50 ° C.
The range of ° C is preferred. The treatment time is 2 to 120 seconds, preferably 2 to 60 seconds. A more preferable range is 15 to 60 seconds. Less than 2 seconds will not react well,
It is difficult to form a film with excellent corrosion resistance. Even if processing is performed for more than 60 seconds, the improvement in performance is reduced.

Next, the treatment process of aluminum DI tin and tin DI can to which the surface treatment method of the present invention is applied will be outlined. The treatment liquid of the present invention is preferably used in the following process. Surface cleaning of DI can: Degreasing, water washing, film formation treatment Treatment temperature: Room temperature to 50 ° C Treatment method: Spraying or dipping Treatment time: 2 to 120 seconds Water washing, deionized water washing, drying

[0018]

The treatment liquid of the present invention forms a film mainly containing an oxide of titanium or zirconium on the surface of an aluminum DI can, and forms a film mainly containing tin oxide on the surface of a tinplate DI can. The reason why it is possible to be used for different kinds of objects in this way is that the oxidizing agent and hydrofluoric acid and / or fluoride coexist in the treatment liquid, and the upper limits thereof are specified.

[0020]

EXAMPLES Some examples of the surface treatment liquid of the present invention will be given below, and their usefulness will be shown in comparison with comparative examples.

Aluminum DI can An aluminum DI can made by subjecting an aluminum plate to DI processing is cleaned with a heated aqueous solution of an acid degreasing agent (registered trademark PAL CLEAN 400, manufactured by Nippon Parkerizing Co., Ltd.) and then subjected to surface treatment. did.

Tinplate DI can A tinplate DI can made by tin-processing a tin-plated steel plate is weakly alkaline degreasing agent (registered trademark Fine Cleaner 436).
1A, manufactured by Nihon Parkerizing Co., Ltd.) was used for surface treatment after cleaning.

Corrosion Resistance The corrosion resistance of aluminum DI cans was evaluated by immersing the treated cans in boiling water for 30 minutes and then blackening them. That is, it is preferable that blackening does not occur. The corrosion resistance of tinplate DI cans was evaluated by the iron exposure (IEV). The measurement of IEV is U.
According to S. Patent 4332646. The lower the IEV value is, the more excellent the corrosion resistance is, and usually 150 or less is good.

Paint adhesion Paint adhesion is applied to the surface of the treated can with an epoxyurea-based paint for cans with a coating thickness of 5 to 7 μm and baked at 215 ° C. for 4 minutes to make the cans into strips of 5 × 150 mm. It was cut and thermocompression-bonded with a polyamide film to give a test piece, which was peeled off by the 180-degree peel test method, and the peel strength at that time was evaluated. Therefore, the greater the peel strength, the better the paint adhesion. Generally, it is good if the width is 1.5 kgf / 5 mm or more.

Example 1 Surface treatment liquid 1 for washed aluminum DI tin and tin DI can
Was heated to 40 ° C. and sprayed for 30 seconds. Then, it was washed with tap water, further sprayed with deionized water of 3 MΩcm or more for 10 seconds, and then dried in a hot air drying oven at 180 ° C. for 3 minutes. Then, the corrosion resistance and adhesiveness of this DI can were evaluated. Surface treatment liquid 1 75% Phosphoric acid (H3PO4) 69ppm (PO43-: 50ppm) 20% Fluorozirconic acid (H2ZrF6) 500ppm Zr4 +: 44ppm 20% Hydrofluoric acid (HF) 210ppm Overall F-1: 95ppm 30% excess Hydrogen oxide (H2O2) 166ppm (H2O2: 50ppm) pH 3.0 (adjusted with ammonia water)

Example 2 The surface treatment liquid 2 was heated to 30 ° C. and spray-treated for 15 seconds on the washed aluminum DI can and tinned DI can. Then, as in Example 1, washing with water, washing with deionized water, drying, and then
The corrosion resistance and adhesion of this DI can were evaluated. Surface treatment liquid 2 75% Phosphoric acid (H3PO4) 69ppm (PO43-: 50ppm) 20% Fluorozirconic acid (H2ZrF6) 1000ppm Zr4 +: 88ppm 20% Hydrofluoric acid (HF) 210ppm Overall F-: 150ppm 30% Peroxidation Hydrogen (H2O2) 166ppm (H2O2: 50ppm) pH 3.3 (adjusted with ammonia water)

Example 3 A surface treatment liquid 3 was prepared from washed aluminum DI tin and tin DI can.
Was heated to 35 ° C. and sprayed for 15 seconds. Then, it was washed with water, washed with deionized water and dried in the same manner as in Example 1, and thereafter, the corrosion resistance and adhesion of this DI can were evaluated. Surface treatment liquid 3 75% Phosphoric acid (H3PO4) 69ppm (PO43-: 50ppm) 20% Fluorotitanic acid (H2TiF6) 500ppm Ti4 +: 29ppm 20% Hydrofluoric acid (HF) 210ppm Overall F-: 110ppm 30% Peroxidation Hydrogen (H2O2) 664ppm (H2O2: 200ppm) pH 2.5 (adjusted with ammonia water)

Example 4 A surface treatment liquid 4 was prepared from the washed aluminum DI can and tinplate DI can.
Was heated to 40 ° C. and sprayed for 30 seconds. Then, it was washed with water, washed with deionized water and dried in the same manner as in Example 1, and thereafter, the corrosion resistance and adhesion of this DI can were evaluated. Surface treatment liquid 4 75% phosphoric acid (H3PO4) 138ppm (PO43-: 100ppm) 20% fluorotitanic acid (H2TiF6) 500ppm Ti4 +: 29ppm 20% hydrofluoric acid (HF) 210ppm Overall F-: 110ppm 30% peroxide Hydrogen (H2O2) 166ppm (H2O2: 50ppm) pH 3.5 (adjusted with ammonia water)

Example 5 As described above, in the case of the combined treatment liquid, the film performance in the presence of different metal ions eluted from the DI can is important. 500 ppm of tin ions were mixed in the surface treatment liquid 1, and the surface treatment liquid was heated to 60 ° C. and sprayed for 30 seconds. After the treatment, it was washed with water and dried under the same conditions as in Example 1.

Example 6 100 ppm of aluminum ions were mixed in the surface treatment liquid 1,
The surface treatment solution was heated to 30 ° C. and sprayed for 30 seconds. After the treatment, it was washed with water and dried under the same conditions as in Example 1.

Example 7 50 ppm of tin ions were mixed in the surface treatment liquid 2, and the surface treatment liquid was heated to 60 ° C. and sprayed for 30 seconds.
After the treatment, it was washed with water and dried under the same conditions as in Example 1.

Example 8 100 ppm of aluminum ions were mixed in the surface treatment liquid 2,
The surface treatment solution was heated to 30 ° C. and sprayed for 30 seconds. After the treatment, the DI can was washed with water and dried under the same conditions as in Example 1, and then the DI can was evaluated for corrosion resistance and adhesion.

COMPARATIVE EXAMPLE 1 A surface treatment liquid 5 was prepared from washed aluminum DI tin and tin DI can.
Was heated to 30 ° C. and sprayed for 30 seconds. Then, as in Example 1, washing with water, washing with deionized water, drying, and then
The corrosion resistance and adhesion of this DI can were evaluated. Surface treatment liquid 5 75% Phosphoric acid (H3PO4) 69ppm (PO43-: 50ppm) 20% Fluorozirconic acid (H2ZrF6) 500ppm Zr4 +: 44ppm 20% Hydrofluoric acid (HF) 210ppm Overall F-: 95ppm pH 3.0 (Adjust with ammonia water)

Comparative Example 2 A surface treatment liquid 6 was prepared from the washed aluminum DI tin and tin DI can.
Was heated to 30 ° C. and sprayed for 30 seconds. Then, as in Example 1, washing with water, washing with deionized water, drying, and then
The corrosion resistance and adhesion of this DI can were evaluated. Surface treatment liquid 6 75% Phosphoric acid (H3PO4) 69ppm (PO43-: 50ppm) 20% Hydrofluoric acid (HF) 210ppm F-: 40ppm pH 3.0 (adjusted with ammonia water)

Comparative Example 3 50 ppm of tin ions were mixed in the surface treatment liquid 5, and the surface treatment liquid was heated to 30 ° C. and sprayed for 30 seconds.
After the treatment, it was washed with water and dried under the same conditions as in Example 1, and then,
The corrosion resistance and adhesion of this DI can were evaluated.

Comparative Example 4 The washed aluminum DI can and tinplate DI can were spray-treated with a commercially available aluminum DI can surface treatment liquid (registered trademark Aloydine 404 manufactured by Nippon Parkerizing Co., Ltd.) at 30 ° C. for 30 seconds. Then, it was washed with water, washed with deionized water and dried in the same manner as in Example 1, and thereafter, the corrosion resistance and adhesion of this DI can were evaluated.

Comparative Example 5 The washed aluminum DI can and tinplate DI can were heated to 30 ° C. with a commercially available surface treatment liquid for tinplate DI can (registered trademark Parphos K3482 manufactured by Nippon Parkerizing Co., Ltd.).
Sprayed for seconds. Then, washing with water in the same manner as in Example 1,
Deionized water wash, dry, then the corrosion resistance of this DI can,
The adhesion was evaluated.

[0038]

TABLE 1 Test Results corrosion resistance coating adhesion (kgf / 5 mm width) aluminum (blackening) tin (IEV) 100 5.0 3.5 Example 2 Black without aluminum tin Example 1 blackened No change 100 5.0 3.5 Example 3 No black change 100 5.0 3.5 Example 4 No black change 100 5.0 3.5 Example 5 No black change 100 5.0 3 .5 Example 6 No black discoloration 100 5.0 3.5 Example 7 No black discoloration 100 5.0 3.5 Example 8 No black discoloration 100 5.0 3.5 Comparative Example 1 Some black discoloration 200 2.5 1.5 Comparative example 2 Full black discoloration 300 1.0 l. 0 Comparative Example 3 Full black discoloration 180 1.0 1.0 Comparative Example 4 No black discoloration 300 5.0 1.0 Comparative Example 5 Total black discoloration 100 1.0 3.5

[0039]

As described above, by treating aluminum DI cans and tin DI cans with the surface treatment method according to the present invention, excellent corrosion resistance and paint adhesion can be obtained on the surface of DI cans before painting and printing. It has an excellent effect that it can be applied by low-temperature treatment and can be used in combination with the same treatment liquid.

Claims (2)

[Claims] 1. A phosphate ion and at least one of a zirconium compound and a titanium compound and having a pH of 2.
500 pp in DI can processing liquid having 0-4.0
m or less oxidizer and at least one of hydrofluoric acid and fluoride
A surface treatment liquid for aluminum DI cans and tin DI cans, which further contains 2000 ppm or less of fluorine as a seed. 2. A treatment solution containing at least one of phosphate ions, zirconium compounds and titanium compounds, 500 ppm or less of an oxidizing agent, and at least one of hydrofluoric acid and fluoride of 2000 ppm or less as fluorine, and the surface is cleaned. Aluminum DI can or tinplate DI can are brought into contact with the aluminum DI can and tinplate DI can surface treatment method.