JPH06297639A - Film laminating aluminum material and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an aluminum material having base stability also after polymer processing and having high adhesion to a resin film by a manufacturing method wherein environmental pollution does not occur, processing can be done in a short time and productivity is high, the cost for equipment is low, and processing cost is also low. CONSTITUTION:On an aluminum material having an oxide film with branched micropores having film thickness of 500-5000 angstrom, a resin film is layered. As for manufacturing method, the surface of the aluminum material is electrolyzed by alternating wave form in an alkaline water solution so as to form the oxide film with the branched micropores having the film thickness of 500-5000 angstrom. Or, precedingly, etching processing is performed by an acid solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a container, a capacitor case, a rice cooker after the film is laminated and molded.
The present invention relates to an aluminum material for laminating a film, which is used for an inner pot, an automobile body sheet and the like.

[0002]

2. Description of the Related Art In order to impart corrosion resistance, chemical resistance, etc. of a final product even in the case where it is molded before use,
Lamination of an organic resin film or the like on an aluminum material (particularly, a plate or a coil) has been performed in order to impart lubricity during molding. However, if the adhesion between the resin film and the aluminum material is insufficient in the molding process, the resin film will not peel off during molding, or corrosion will occur from a location with insufficient adhesion, and sufficient performance will not be exhibited. There are cases. This adhesion is
It is greatly affected by the material of the resin film and the type of adhesive, but it is also greatly affected by the condition of the surface of the aluminum material. Therefore, in order to improve the adhesion between the aluminum material and the resin film, the following surface treatment has been conventionally performed on the aluminum material. (1) A phosphoric acid chromate treatment is applied to an aluminum material to improve the adhesion to a resin film by coating the phosphoric acid chromate formed on the surface of the aluminum material. (2) A composite film of a specific resin and a fiber metal compound as disclosed in JP-A-1-114435 is formed (adhesive primer) to improve the adhesion to the resin film. (3) An aluminum hydrated oxide film as disclosed in JP-A-63-126728 is provided to improve the adhesion.

[0003]

However, in the phosphoric acid chromate treatment method (1), the treatment liquid is mainly chromate, phosphate, hydrofluoric acid, etc. and is harmful to the human body, which is an enormous wastewater treatment facility. Is necessary and is not suitable from the viewpoint of environmental protection. In addition, since the phosphoric acid chromate film is prone to cracks due to heating and molding during resin film lamination,
There is a drawback in that the coating film adhesion may decrease in this portion. In addition, the method (2) of forming an adhesive primer not only causes a high cost due to the application of the primer, but also has a problem that productivity is deteriorated because a separate baking process is required. The method of providing the hydrated oxide film of (3) is poor in productivity because it takes a long time to process the hydrated oxide film, and the hydrated oxide film is so hard that cracks are likely to occur during the molding process. In the same manner as in the above case, the adhesion of the coating film may decrease in this part. The present inventors have overcome the above-mentioned drawbacks of the prior art, have no environmental pollution, require only a short processing time, have high productivity, have low equipment costs, and have low processing costs. The present invention has been completed by conducting research to provide a high-performance aluminum plate having a stable base and high adhesion to a resin film.

[0004]

In order to achieve these objects, in the present application, each claim has the following structure. That is, claim 1 is a film laminated aluminum material obtained by laminating a resin film on an aluminum material on which an oxide film having branched micropores having a film thickness of 500 to 5000 angstrom is formed. According to a second aspect of the present invention, the surface of the aluminum material is electrolyzed in an alkaline aqueous solution with an alternating waveform to form an oxide film having branched micropores having a film thickness of 500 to 5000 angstroms. A method for producing an aluminum material for film lamination, which has excellent adhesiveness with. Claim 3
The electrolysis condition is that the amount of electricity exceeds 80 C / dm ² at a current density of 4 to 50 A / dm ^{2 in} an alkaline aqueous solution of pH 9 to 13 at 35 to 85 ° C. A method for producing an aluminum material for film lamination as described above. According to a fourth aspect of the present invention, the concentration is 1 to 30 wt% and the bath temperature is 10 to 90 before the electrolytic treatment with an alternating waveform in an alkaline aqueous solution.
The intermetallic compound is removed by etching treatment with an acidic solution at a temperature of 1 ° C. for several seconds to several tens of seconds, followed by washing with water.
Alternatively, the method for producing an aluminum material for film lamination according to Item 3. Is.

Each constituent element will be described in detail below. The aluminum material that is the subject of the present invention is not limited as long as it is an aluminum alloy that can be molded, and it can be applied to all JIS or AA standard alloys. However, from the viewpoint of cost and workability, 1000 series such as 1100 and 1200, 3
3000 series such as 003, 3004, 5052, 5082
And the like, and 6000 series alloys such as 6061 are preferable. In the present invention, the oxide film obtained by the alternating current electrolytic treatment in the alkaline solution has a film thickness of 500 to 5000 angstrom. In addition, since this oxide film has porous and branched micropores and the surface is clean, not only the initial adhesion to the resin film to be laminated but also the high heating and drawing ratio when laminating the resin film Since cracks do not occur even when deep drawing is performed, strong adhesion can be maintained even after deep drawing of the laminate. If the thickness of the oxide film is less than 500 Å, the adhesion with the resin film will be insufficient. On the other hand, even if the thickness of the oxide film exceeds 5000 angstroms, there is no particular problem, but this is the upper limit of the thickness obtained under normal processing conditions, and there is no particular advantage if the thickness is further increased. The resin film to be laminated is not particularly limited as long as it is appropriately selected according to the use purpose, but is not limited to a polyester film such as PET, a tetrafluoroethylene-6-fluoropropylene copolymer resin film, or the like. A fused fluorine film and a polyolefin film such as polypropylene are preferably used. The thickness of the resin film may be appropriately selected depending on the intended use, but it is usually selected from the range of about 10 to 50 μm. The lamination temperature of the resin film also varies greatly depending on the characteristics of the resin film, but it is usually selected from a temperature of room temperature to about 300 ° C. The alkaline aqueous solution used in the present invention is not particularly limited, but is usually a phosphate such as sodium pyrophosphate, sodium phosphate, potassium phosphate, sodium hydrogenphosphate, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, etc. One or a mixture of two or more kinds of the above-mentioned carbonates, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide is preferable. Further, a surfactant may be contained in order to improve the degreasing property. The pH of this electrolytic solution is in the range of 9 to 13. Particularly preferably 9.5
~ 12. If the pH is less than 9, the degreasing property is poor, the rolling oil on the aluminum surface and the oxide film formed during the production of the aluminum plate are not sufficiently removed, and the porous oxide film having branched micropores to be imparted by the present invention is not formed. Be hindered. In addition, the bath voltage rises and uneven electrolysis is likely to occur, which is not preferable. On the other hand, when the pH exceeds 13, the solubility of the electrolytic solution is too strong and a porous oxide film having excellent adhesiveness cannot be formed, so this should be avoided. The alkaline solution bath temperature is in the range of 35 to 85 ° C. Particularly preferably, it is in the range of 40 to 70 ° C. If the temperature is lower than 35 ° C, the degreasing / cleaning effect is insufficient. On the other hand, if the temperature exceeds 85 ° C, the solubility is so strong that the required oxide film cannot be obtained. The maximum current density in the alternating waveform is 4 to 50 A / dm ² , preferably 5 to
There is 30 A / dm ² . If it is less than 4 A / dm ² , the amount of bubbles generated during electrolysis is insufficient and the surface cleaning effect is poor.
It is not preferable because the formation of the porous oxide film having excellent adhesion is insufficient. If it exceeds 50 A / dm ² , not only the electrolysis voltage becomes too high and it is easy for leakage to occur,
It is not preferable because unevenness in appearance such as "burning" easily occurs due to reaction heat. It is necessary to perform electrolysis for a time when the total amount of electricity exceeds 80 C / dm ² . If the total amount of electricity is 80 C / dm ² or less, the porous oxide film does not form up to a predetermined thickness, so the adhesion with the resin film is insufficient. If you look at it more closely, the amount of electricity when the polarity is positive (anode amount of electricity)
Is preferably in the range of more than 40 C / dm ² .
If the anodic charge is 40 C / dm ² or less, the growth of the porous oxide film is insufficient and the cleaning action is not sufficiently performed. In addition, the amount of electricity when the polarity is negative (cathode amount of electricity)
Is preferably 40 C / dm ² or more. Cathode electricity amount is 4
If it is less than 0 C / dm ² , the cleaning action is insufficient. The anodic electric quantity and the cathodic electric quantity need only satisfy the above-mentioned range, and do not have to be the same electric quantity. The current waveform should be an alternating waveform, such as sine wave alternating current, rectangular wave, trapezoidal wave,
A triangular wave or the like will do. The electrolysis time may be set based on the relationship between the required amount of electricity and the current density, and if the current density is high, a short treatment time will suffice. Industrially, it is preferably several seconds to 30 seconds. The cleaning treatment before electrolysis can be performed as necessary. In particular, in the case of an aluminum alloy having a large amount of alloy components, a large number of intermetallic compounds are present on the surface of the material in the form of crystallized substances or precipitates. (For example, in the case of 5082, Al ₃ Fe, Mg ₂ Si, etc. in the Al-Mg based aluminum alloy) These compounds inhibit the formation of porous oxide film by electrolytic treatment.
That is, the branched porous film as described above is
It is not formed on the surface of intermetallic compounds such as l ₃ Fe and Mg ₂ Si. Therefore, when viewed microscopically, it becomes a fine defect in which an oxide film is not partially formed. The presence of such a defect easily becomes a starting point of peeling after the film is laminated, which causes a deterioration in performance. Such a compound can be removed by etching in an acidic solution and then washing with water. Therefore, as in the third item of the present application, when etching is performed in an acidic solution, followed by washing with water, and then electrolytic treatment with an alternating waveform in the alkaline solution, a uniform branched porous oxide film without defects is obtained. . The acid solution used for etching with the acidic solution of the third section of the present application includes sulfuric acid, nitric acid, hydrochloric acid,
A mineral acid such as phosphoric acid, an organic acid such as sulfamic acid, or a mixed acid thereof may be used. The concentration is 1 to 30 wt%, preferably 2
~ 20 wt%. If the concentration is less than 1 wt%, the etching effect is low and the intermetallic compound or precipitate cannot be sufficiently removed. If the concentration exceeds 30 wt%, the handling risk increases, which is unsuitable. The bath temperature is 10 to 90 ° C, preferably 20 to 50 ° C. If the temperature is lower than 10 ° C., the etching rate is slow and the processing time becomes extremely long, which is not suitable, and if the temperature exceeds 90 ° C., a large amount of gas and mist are generated, which is dangerous and the facility cost rapidly increases. Time is 1
The range of seconds to several tens of seconds is preferable, and the range of several seconds to several tens of seconds is preferable.

[0006]

In the present invention, electrolytic treatment is carried out using an alternating waveform in an alkaline solution at a high temperature of 35 to 85 ° C. By such electrolytic treatment, as described in detail below, the surface of the aluminum material is strongly degreased and washed, and at the same time,
A porous oxide film having excellent adhesion to the resin film is produced. First, regarding the degreasing / cleaning action, the alkaline solution itself has degreasing properties, and in addition, because of the high temperature, stronger degreasing properties are exhibited. In addition, in the electrolysis using the alternating waveform, oxygen gas is generated during the anodic reaction, while hydrogen gas is generated during the cathodic reaction, so during the anodic reaction, degreasing and degreasing of organic substances adhering to the surface of the aluminum material is caused. The cleaning action works,
During the reaction, the mechanical cleaning action is performed by the expansion of hydrogen bubbles on the plate surface. Therefore, electrolysis with an alternating waveform in a high-temperature alkaline solution synergistically functions the above-mentioned actions to exert a strong degreasing / cleaning effect, which adversely affects the adhesion to the resin film in an extremely short time. Oil components such as rolling oil on the surface of the aluminum material to be given, and lumps of thermal oxide film formed during plastic working such as rolling are completely removed to form an oxide film having a clean surface. Furthermore, in the present invention, since the electrolytic treatment is performed in an alkaline solution at a high temperature with an alternating waveform, electrolysis can be performed at a high current density and a high-speed chemical reaction occurs. That is, the dissolution reaction of the oxide film by the high temperature alkaline aqueous solution and the reaction of forming the oxide film at the anode having the polarity occur at high speed. In addition, the oxide film formed by the dissolution reaction on the surface of the oxide film and the intermittent oxide film growth due to the alternating waveform is much more porous than the oxide film anodized by DC electrolysis in a general acidic aqueous solution. Micropores of very complex structure with quality and branching are formed. On the other hand, an anodized film obtained by direct current electrolysis is a brittle oxide film having a low pore density. Therefore, the stress received during the molding process cannot be relaxed, the oxide film itself is destroyed, and as a result, the resin film laminated on the oxide film also suffers damage such as cracks and defects. The formation of this porous oxide film can be realized only by performing electrolytic treatment in an alkaline aqueous solution with an alternating waveform. That is, in the electrolytic treatment by general direct current electrolysis, since the pore density is low, the current hardly flows, the bath voltage rises rapidly, and film defects such as "burning" are likely to occur. Electrolysis becomes impossible. In addition, an acidic aqueous solution of phosphoric acid, sulfuric acid, etc., which is generally used for forming an anodized film, has a small cleaning effect on the surface, so that the bath voltage is likely to rise and electrolysis at a high current density is impossible. In this way, the oxide film electrolytically treated in an alkaline aqueous solution in an alternating waveform has a clean surface, and since it is a porous oxide film having a branched and complicated micropore structure, it is not mixed with the resin film to be laminated in the initial stage. Not only the adhesion, but also the effect of relieving the stress on the coating is strong even when heating at the time of laminating resin films and deep drawing with a high drawing ratio. It is possible to maintain strong adhesion even after drawing.

Further, degreasing cleaning and formation of a porous oxide film are carried out by the same electrolytic treatment in the same tank, and the electrolysis time is also shorter, so that the working time as a whole is remarkably shortened as compared with the conventional one, and the productivity is improved. In addition, the facility cost will be significantly reduced. In addition, since a substance harmful to human body such as chromium is not used, it is a great advantage in terms of operation and environmental protection. Thus, the present invention provides a manufacturing method that not only has good adhesion to a resin film, but also requires a minimum number of steps for a short time, and that is inexpensive in terms of equipment and operation. Also, for materials that produce a lot of intermetallic compounds on the surface, after removing the precipitates by etching with an acid-based solution and performing electrolytic treatment in an alkaline aqueous solution, a porous oxide film is formed on the entire surface of the aluminum alloy. The adhesiveness with is further improved.

[0008]

EXAMPLES Next, examples of the present invention will be described. (Example 1) A JIS A1100 aluminum plate was cold-rolled to obtain a plate material having a plate thickness of 0.3 mm. This is subjected to a base treatment as shown in Table 1, washed with water and dried, and then a fluorine-based resin film having an olefin-based adhesive layer having a thickness of 30 μm is applied to each pretreated aluminum material under a pressure of 7 kg / cm.
² , thermocompression-bonded under the conditions of temperature = 300 ° C. and 10 minutes to produce a laminated plate. This laminated board is molded with a total squeeze rate of 40%,
A cylindrical container having a diameter of 5 mm and a height of 11 mm was prepared. Then, this cylindrical container was trimmed and retorted (121 ° C,
After 3 h), the adhesion state of the resin film was observed. The results are shown in Table 1. In each of the invention examples, there was no peeling of the resin film, which was good. On the other hand, in each of the comparative examples, the resin film peeled off.

[0009]

[Table 1]

(Example 2) A JIS A5052 aluminum plate is cold-rolled to form a plate material having a plate thickness of 0.3 mm. This is subjected to a base treatment as shown in Table 2, washed with water and dried,
Nylon-based resin film containing adhesive components with a thickness of 30 μm is applied to each pre-treated aluminum material at a pressure of 5k.
Thermocompression bonding was performed under the conditions of g / cm ² and temperature = 230 ° C. for 10 minutes to prepare a laminated plate. This laminated board is 40% in total
Was molded into a cylindrical container having a diameter of 5 mm and a height of 11 mm. Then, this cylindrical container was trimmed and subjected to retort treatment (121 ° C., 3 hours), and then the adhesion state of the resin film was observed. In each of the invention examples, there was no peeling of the resin film, which was good. On the other hand, in each of the comparative examples, the resin film peeled off.

[0011]

[Table 2]

(Example 3) A JIS A5082 aluminum alloy plate was cold-rolled to obtain a plate material having a plate thickness of 0.3 mm. This is subjected to a base treatment as shown in Table 3, washed with water and dried, and then each pretreated aluminum material has a thickness of 30 μm.
The nylon-based resin film containing the adhesive component was heat-pressed under the conditions of pressure = 5 kg / cm ² and temperature = 230 ° C. for 10 minutes to produce a laminated plate. This laminate has a total squeeze rate of 4
It was molded with 0% to obtain a cylindrical container having a diameter of 5 mm and a height of 11 mm. Then, the cylindrical container was trimmed and subjected to a severe retort treatment (121 ° C., 12 h), and then the film adhesion state was observed. Despite the severe retort treatment conditions, all of the invention examples in claim 4 were good with no peeling of the film. On the other hand, in the comparative example of claim 4, the film peeled off under the severe retort treatment conditions.

[0013]

[Effect] The oxide film formed by electrolytically treating in an alkaline aqueous solution with an alternating waveform in this way has a clean surface, and is very porous and has a branched structure, so it adheres to the resin film. Since the adhesiveness is remarkably improved, and since it is rich in flexibility, cracking and peeling of the resin film do not occur even when molding is performed, it is possible to maintain strong adhesion even after molding. In addition, degreasing cleaning and formation of a porous oxide film are performed simultaneously in the same tank by the same electrolytic treatment, and because the time is shorter, the work time is shorter than before, productivity is improved, and equipment costs are low. . Further, unlike chemical conversion treatment, it does not use a substance harmful to the human body such as chromium, which is a great advantage in terms of operation and maintenance. Furthermore, even for a material that produces a large amount of intermetallic compounds on its surface, the same effect can be obtained by adding a step of removing the precipitate by etching with an acid-based solution before electrolytically treating it in an alkaline aqueous solution.

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C25F 3/04 A 8414-4K

Claims (4)

[Claims] 1. A film laminated aluminum material obtained by laminating a resin film on an aluminum material on which an oxide film having branched micropores having a film thickness of 500 to 5000 angstrom is formed. 2. A film thickness of 500 to 50 obtained by subjecting the surface of an aluminum material to an electrolytic treatment with an alternating waveform in an alkaline aqueous solution.
A method for producing an aluminum material for film lamination having excellent adhesion to a laminated resin film, characterized in that an oxide film having branched micropores of 00 angstrom is formed. 3. The electrolytic treatment is carried out under the condition that the pH is 9 to 13 (35).
Current density 4 to 50 A / in alkaline aqueous solution at ~ 85 ° C
method of producing a film laminating aluminum material according to claim 2 in which the quantity of electricity is equal to or in excess of 80C / dm ² at dm ^2. 4. A concentration of 1 to 30 wt% and a bath temperature of 10 to 90 ° C. before electrolytic treatment with an alternating waveform in an alkaline aqueous solution.
The method for producing an aluminum material for film lamination according to claim 2 or 3, wherein the acidic solution is subjected to etching treatment for 1 second to several tens of seconds to remove intermetallic compounds and washed with water.