JP2001162718A - Method for producing resin-coated aluminum plate excellent in adhesion and workability - Google Patents

Abstract

(57) [Summary] [Problem] Al laminated with a thermoplastic resin film
In manufacturing the board, the adhesion between the film and the Al board and the workability of the resin film itself can be sufficiently ensured. SOLUTION: A base treatment step of applying and drying an aqueous solution containing an organic resin, a metal ion and an acid to an Al plate after a degreasing treatment, and drying the Al plate at a temperature equal to or higher than a glass transition temperature of a thermoplastic resin film and a melting point (Tm). Heating to a temperature within the range of
A laminating step of laminating a thermoplastic resin film on at least one surface of the Al plate at a temperature within the range and pressing by a laminating roll, followed by a cooling step of rapidly cooling, which is characterized by adhesion and processing. Of manufacturing resin-coated Al plate with excellent properties. Between the laminating step and the cooling step, a reheating step of heating the resin film within a specific temperature range may be added, or a multilayer resin film may be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a resin film-coated aluminum plate obtained by laminating a thermoplastic resin film on one or both surfaces of an aluminum plate. The present invention relates to a method for producing a thermoplastic resin-coated aluminum plate in which the adhesion to the plate does not decrease and the workability of the resin film itself is excellent. In this specification, the aluminum plate includes not only a pure aluminum plate but also various aluminum alloy plates.

[0002]

2. Description of the Related Art Conventionally, a resin film-coated metal plate obtained by laminating a resin film on one or both surfaces of a metal plate has been widely used in various fields such as electric parts, furniture, and interior and exterior building materials. In recent years, beverage cans and other products have been developed for the purpose of environmental protection by reducing the emission of VOC and CO ₂ , and for the purpose of improving the stability and quality of contents by using the high barrier properties of polyester films. Polyester film-coated metal sheets are frequently used as container materials.

[0003] The film is composed of a single-layer film and a thermocompression bonding method, a two-layer resin film having different melting points and a thermocompression bonding method, or a method of interposing an adhesive layer between a metal plate and a resin film. There is a method of coating. The aluminum plate used for these is subjected to pretreatment such as etching with an alkali solution or an acid solution, phosphoric acid chromate treatment, anodizing treatment, electrolytic chromic acid treatment, etc., in order to improve corrosion resistance and adhesion to the film,
Phosphoric acid chromate treatment is most commonly performed. These resin-coated metal sheet materials are subjected to various forming processes such as bending, drawing, ironing, and overhang to produce products. Although there are still few examples of a resin-coated aluminum plate, studies are being made for various uses.

[0004]

As described above, the resin-coated metal sheet is subjected to various forming processes to be a product. For example, aluminum drawn ironing cans used for beverage cans such as beer and carbonated beverages are generally drawn, redrawn,
It is formed by ironing three times and necking and flanging. As the degree of working, the thickness is reduced to as much as 60% or more of the original plate thickness. However, when such severe processing is performed, the adhesion between the aluminum plate and the resin film is reduced, and peeling may occur during the processing. Even if the final product can be processed, there is a case where corrosion resistance is poor due to poor adhesion, which may cause a problem. Further, even if the adhesion between the aluminum plate and the resin film is good, if the workability of the resin film itself is poor, the resin film is cracked or broken during the processing, which also leads to deterioration of corrosion resistance.

[0005]

Means for Solving the Problems In order to solve such problems, the present inventors have conducted intensive experiments and studies and as a result, heated an aluminum plate having been subjected to an appropriate base treatment to an appropriate temperature range. After laminating the thermoplastic resin film and pressing with a laminating roll, the resin film is reheated to a temperature range appropriately adjusted as necessary, and rapidly cooled, so that the adhesion between the aluminum plate and the resin film is Have been found, and the processability of the resin film itself has also been improved, leading to the present invention.

More specifically, the invention according to claim 1 is characterized in that an aqueous solution containing an organic resin and metal ions is contained in an aluminum plate after degreasing treatment in a total amount of 0.2 to 3 g / m ² after drying. A base treatment step of applying and drying the metal in an amount of 5 to 50 mg / m ² , followed by heating the aluminum plate at a temperature not lower than the glass transition temperature of the thermoplastic resin film and lower than the melting point (Tm). And a laminating step of laminating a thermoplastic resin film on at least one surface of the aluminum plate at a temperature within the range and pressing with a laminating roll, followed by a cooling step of rapidly cooling. This is a method for producing a resin-coated aluminum plate having excellent adhesion and workability.

Further, according to the present invention, between the laminating step and the cooling step, the resin film is heated so that the temperature of the resin film is in the range of (Tm−50) ° C. or more and (Tm + 30) ° C. or less. The method for producing a resin-coated aluminum plate excellent in adhesion and workability according to claim 1, wherein a heating step is added.

Further, in the invention of claim 3, when a thermoplastic resin film having a multilayer structure of two or more layers is used, the temperature of the aluminum plate in the laminating step is set to a value not lower than the glass transition temperature of the resin film of the adhesive layer in contact with the plate. The method for producing a resin-coated aluminum plate having excellent adhesion and workability according to claim 1 or 2, wherein the temperature is set to be equal to or lower than the melting point of the resin film of the outermost layer.

According to a fourth aspect of the present invention, when a thermoplastic resin film having a multilayer structure of two or more layers is used, the temperature of the aluminum plate in the laminating step is set to a value not lower than the glass transition temperature of the resin film of the adhesive layer in contact with the plate. In addition, the temperature of the resin film in the reheating step is set to be equal to or lower than the melting point of the outermost resin film, and the temperature of the resin film in the reheating step is equal to or higher than (Tm1-50) ° C. according to the highest melting point (Tm1) of the resin in each of the layers constituting the film. 3. The method for producing a resin-coated aluminum plate having excellent adhesion and workability according to claim 1 or 2, wherein reheating is performed to (Tm1 + 30) ° C. or lower.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The upper part (A) of FIG. 1 shows a conceptual structure of an apparatus for carrying out the method of the invention of claim 2 by a continuous laminating method, and the lower part (B) of FIG. FIG. 1A shows the transition of the temperature of the aluminum plate and the temperature of the thermoplastic resin when the thermoplastic resin is continuously laminated on the aluminum plate. FIG. 1 shows an example in which a resin film is laminated on both sides of an aluminum plate. Further, in the following description, first, the entire configuration of the invention will be described in the case of laminating using a resin film having a single-layer configuration,
Thereafter, a case where a resin film having a plurality of layers is used will be described again.

In FIG. 1A, an aluminum plate 1 which has been subjected to a degreasing treatment and a base treatment for applying and drying an aqueous solution containing an organic resin, a metal ion and an acid is previously formed into a coil, for example. Aluminum plate 1
Is continuously fed from the supply reel 3 and, while passing through the first heating means 5, has a temperature equal to or higher than the glass transition temperature (Tg) of the resin of the thermoplastic resin film to be laminated and the melting point (Tg).
m) to a temperature T1 within the range less than m). Subsequently, the aluminum plate 1 reaches between a pair of upper and lower laminate rolls (pressure rolls) 7A and 7B. This laminating roll 7A,
At a position immediately before 7B, the thermoplastic resin films 9A and 9B to be laminated are continuously supplied to one side or both sides (both sides in the illustrated example) of the aluminum plate 1 and are pressed by the laminating rolls 7A and 7B to form aluminum. It is bonded to the surface of the plate 1. The steps so far correspond to the laminating step in the method of the present invention.

Then, in the case of claim 2, the aluminum plate 1 passes through the second heating means 11 in a state where the thermoplastic resin is temporarily bonded as described above, during which the thermoplastic resin film 9A, 9B is heated to a temperature T2 which is equal to or higher than (Tm-50) ° C and lower than (Tm + 30) ° C. This step corresponds to the reheating step in the method of the present invention.

Regardless of whether the reheating step is performed or not, the laminated aluminum plate 1 is rapidly cooled immediately thereafter and continuously wound on the take-up reel 13.

In the above, the undercoating step is the most important step of the present invention. In other words, the present inventors performed an application-type base treatment after applying a proper amount of an aqueous solution containing an organic resin and a metal ion and an acid after the degreasing treatment. It has been found that this is the most suitable method for improving the properties, and the present invention has been completed.

Generally, as a base treatment before resin coating, a reactive chemical conversion treatment such as a phosphoric acid chromate treatment or a zirconium phosphate treatment is performed. However, in all of these treatments, an inorganic hard film is formed, and there is a defect that the adhesion during the resin coating treatment is excellent but the adhesion during the processing is inferior. The cause is that when the aluminum plate material is subjected to strong processing, these inorganic hard undercoating films cannot follow the processing and become crushed and dispersed, and the adhesion between the resin film and the aluminum plate material decreases. It depends. Therefore, as a result of various experiments and studies by the present inventor, it was found that applying a coating-type base treatment in which a resin is contained and an organic film and an inorganic film are combined is the most appropriate method for maintaining processing adhesion. I found it. By containing a resin, it does not break and disperse like an inorganic film even when subjected to strong processing, and even after processing, it has a slight film thickness but exists as a uniform film, and the resin film to be coated Can maintain the adhesion.

As the undercoating agent, an organic resin such as polyacrylic acid, acrylic-modified epoxy, urethane-modified epoxy, or a copolymer resin thereof may be added to Cr, Zr, Mg,
One or more of metal ions such as Ba, Fe, Ti, and Li, and others containing an acid that reacts with an aluminum base such as phosphoric acid or hydrofluoric acid are used. Here, it is considered that the metal ion oxidizes the OH group of the hydroxyl group-containing monomer contained in the organic resin, strengthens the crosslinking between the resin molecules, and forms a dense film. It is also considered that the synergistic effect of OH groups remaining without being oxidized by metal ions and phosphoric acid and the like ensures strong adhesion to the coating resin. The aqueous solution containing such an organic resin, metal ions and acid is dried in a total amount of 0.2 to 3 g / m ² , and the amount of a metal such as Cr or Zr in the film is 5 to 50 mg / m ² .
Coated to a ² to dryness. 0.2mg in total film
/ M ² , or less than 5 mg / m ^{2 in} the amount of metal, does not provide sufficient adhesion, workability, and corrosion resistance. Further, if the total amount of the coating exceeds 3 g / m ² or the amount of the metal exceeds 50 mg / m ² , the effect is not only saturated but also uneconomical.

The first purpose is to wash off the lubricating oil used at the time of rolling, and the second purpose is to remove the oxide film on the surface of the plate to improve the conformability of the undercoating agent. Is subjected to a degreasing treatment prior to the base treatment. In the degreasing step, the surface of the aluminum plate is activated as much as possible by a method of degreasing using an acidic or alkaline degreasing solution or a method of using a combination of degreasing with an alkali and degreasing with an acid.

Next, the laminating step is a step of heating the aluminum plate, laminating a thermoplastic resin film on one side or both sides thereof, and applying pressure by a laminating roll to temporarily adhere the thermoplastic resin film to the surface of the aluminum plate. However, the purpose of heating the aluminum plate in this laminating step is to soften the thermoplastic film in contact with the aluminum plate and to bond the film to the aluminum plate by pressing with a laminating roll. If the heating temperature T1 in the laminating step is lower than the glass transition temperature of the resin, the softening of the resin film becomes insufficient, and the resin film may not be sufficiently adhered to the surface of the aluminum plate due to air entrainment or the like.

On the other hand, the higher the heating temperature, the higher the adhesion can be obtained. However, if the heating temperature is higher than the melting point of the resin, the resin film is melted and adheres to the laminating roll, which causes a problem that the lamination cannot be performed smoothly. Therefore, the heating temperature of the aluminum plate in the laminating step needs to be in a temperature range not lower than the glass transition temperature of the resin constituting the resin film to be used and lower than the melting point.

The heating means for heating the aluminum plate in the laminating step is not particularly limited.
Any method such as a roll heating method, a hot air heating method, an infrared heating method, an electric heating method, and an induction heating method may be applied. However, among these, the roll heating method is the most suitable in terms of making the temperature distribution uniform and efficient.

The surface temperature of the roll at the time of pressurization by the laminating roll is not particularly limited, but may be generally slightly lower than the temperature of the aluminum plate. The pressure applied by the laminating rolls is not particularly limited, but generally, a linear pressure of 20 N / cm or more is appropriate. Pressing force by laminating roll is 20N / c in linear pressure
If it is less than m, sufficient adhesion may not be obtained.
The upper limit of the pressing force is not particularly limited, but may be a common sense pressure that does not damage the device.

Although a certain degree of adhesion can be obtained even if the process proceeds to a cooling step to be described later immediately after the lamination step, in order to obtain better adhesion, a further repetition is required between the lamination step and the cooling step. A heating step is added. In the reheating step added between the laminating step and the cooling step, the thermoplastic resin film temporarily bonded to the surface of the aluminum plate as described above is heated to (Tm-50) ° C with respect to its melting point (Tm). ~ (Tm +
30) Heating to a temperature within the range of ° C. by an infrared heating method.

The first purpose of the heating in the reheating step is to bond the resin film to the surface of the aluminum plate with sufficient adhesion. That is, by further softening and melting the resin film temporarily bonded in the laminating step, air entrapped between the aluminum plate and the film is removed by permeating the film, and the rolls on the aluminum plate surface and An object of the present invention is to allow the resin of the film to penetrate into minute recesses such as oil pits and to firmly adhere the film to the aluminum plate.

The second purpose of the heating in the reheating step is to disrupt the orientation of the oriented and crystallized resin film and to impart good workability to the film. That is, in general, a film oriented and crystallized by biaxial stretching is often used as a resin film for lamination, and since the oriented crystallized state does not have sufficient workability, the finally obtained resin is Cracks occur in the resin film when pressing the film-coated aluminum plate,
There is a possibility that it may be broken or difficult to process. Therefore, in order to impart sufficient workability, it is necessary to collapse the orientation by heating.

The heating temperature of the resin film in the reheating step for these purposes is (Tm-50) ° C. or higher,
(Tm + 30) ° C. or lower. That is, the resin film heating temperature in the reheating step is (Tm−5).
0) When the temperature is lower than 0 ° C., the softening and melting of the resin film does not sufficiently proceed, so that a high adhesion force cannot be obtained. Therefore, the resin film may be peeled off at the time of processing or the like, and the collapse of the orientation of the resin film is not sufficient. Poor workability,
Therefore, the resin film may be cracked or broken at the time of processing, which may make processing difficult.
Therefore, the lower limit of the heating temperature of the resin film in the reheating step is (Tm-50) ° C. When the heating temperature is (T
If the temperature is higher than (m + 30) ° C., a part of the molecular structure constituting the resin film may be cut off. In such a case, the film surface may be roughened or cracked during processing. In addition, the corrosion resistance and heat resistance also deteriorate, and when performing heating such as retort treatment, peeling or whitening of the resin film may occur,
Therefore, the upper limit of the heating temperature of the resin film in the reheating step is (Tm + 30) ° C.

Here, it is preferable to use an infrared heating method as a heating method in the reheating step. That is, since the heating temperature T2 in the reheating step is generally set to a temperature higher than the heating temperature in the laminating step, the strength of the coated aluminum plate is determined by the heating temperature in the reheating step. Normal. On the other hand, the aluminum sheet has a remarkably low softening temperature as compared with a steel sheet or the like, so that the strength may be significantly reduced by heating in the reheating step. As described above, this reduction in strength causes a particular inconvenience when the coated plate is applied to an application requiring high pressure resistance, such as a beverage can. Therefore, the heating temperature in the reheating step is desirably as low as possible, but if the heating temperature in the reheating step is low, the resin film cannot be sufficiently softened and melted as described above, and Is difficult to disintegrate, and as a result, it is difficult to obtain sufficient adhesion and good workability. In this way, prevention of the strength reduction of the aluminum plate,
Ensuring sufficient adhesion and workability of the resin film are mutually contradictory in relation to the heating temperature in the reheating step. In order to overcome such conflicting objectives, it is most appropriate to apply an infrared heating method as a heating method.

Immediately after the laminating step or the reheating step, the thermoplastic resin is rapidly cooled to the glass transition temperature or lower. Here, the cooling rate is 40 ° C./sec or more, preferably 50 ° C./sec or more. It is necessary to rapidly cool the crystallization temperature range which differs depending on the type of the resin used. However, since the crystallization temperature range is higher than the glass transition temperature, it is sufficient to rapidly cool the glass transition temperature. For example, 200 ° C for general polyester
The temperature range from to the glass transition temperature is rapidly cooled. Unless this temperature range is rapidly cooled, unnecessary crystallization is caused by the resin, which causes undesired whitening and reduced adhesion.

Next, when the thermoplastic resin film laminated on one or both sides of the aluminum plate has a multilayer structure composed of two or more kinds of thermoplastic resins, that is, a third or fourth aspect of the present invention. The case of the method of the present invention will be described.

When a resin film having a multi-layer structure is used, the basic process and its operation are the same as those when the resin film having a single-layer structure is used. Further, the heating temperature of the resin film in the reheating step needs to be determined according to the resin of each layer constituting the resin film. That is, in the case of a resin film having a multilayer structure of two or more layers, at least a layer in contact with the aluminum plate is a layer to be finally bonded to the aluminum plate (hereinafter referred to as an adhesive layer),
In the final cover plate, there is a layer exposed on the outer surface side (hereinafter referred to as an outermost layer), and in the case of three or more layers, one or more intermediate layers are interposed between the adhesive layer and the outermost layer. However, the heating temperature of the aluminum plate in the laminating step is determined according to the glass transition temperature of the resin of the adhesive layer and the melting point of the resin of the outermost layer. It is necessary to determine according to the melting point of the resin having the highest melting point.

Specifically, first, the heating temperature of the aluminum plate in the laminating step is a temperature not lower than the glass transition temperature of the resin constituting the adhesive layer and less than the melting point of the resin constituting the outermost layer. There is a need to. That is, if the heating temperature in the laminating step is lower than the glass transition temperature of the resin of the adhesive layer, the resin of the adhesive layer is insufficiently softened, and the resin film is sufficiently adhered to the surface of the aluminum plate by air entrainment or the like. It may not be done. On the other hand, if the heating temperature in the laminating step is equal to or higher than the melting point of the resin of the outermost layer, the resin of the outermost layer may be melted and adhere to the laminating roll, and the lamination may not be performed smoothly.

In the laminating step in which a resin film having a plurality of layers is used, in order to increase the adhesion of the resin film to the aluminum plate as much as possible, the temperature of the adhesive layer reaches the melting point and It is desirable that the resin be completely melted and pressed by a laminating roll. However, if the melting point of the resin of the outermost layer is equal to or lower than the melting point of the resin of the adhesive layer, the resin of the outermost layer is in a molten state while the resin of the adhesive layer is in a molten state. Disadvantageously adheres to the laminating roll. Therefore, it is desirable to select the resin of the outermost layer whose melting point is lower than the melting point of the resin of the adhesive layer. Then, in the heating of the laminating step, as described above, the adhesive layer is completely melted to increase the adhesion, and further, so as not to melt the resin of the outermost layer, the melting point of the resin of the adhesive layer is higher than the melting point of the resin of the outermost layer. It is desirable to heat at a low temperature.

The heating temperature in the reheating step in the case of using a resin film having a multilayer structure is as follows: Tm1 is the melting point of the resin having the highest melting point among the resins of the plural layers constituting the resin film. , (Tm1-50) ° C or higher, (Tm
(m1 + 30) ° C. or lower. In other words, the purpose of heating the resin film in the reheating step is not only to bond the resin film to the aluminum plate surface with sufficient adhesion force as described above, but also to disintegrate the orientation of the crystallized resin film and to form a favorable film. It is also important to impart good workability, the adhesive layer among the layers of the resin film having a multilayer structure, the collapse of the orientation has progressed to some extent by heating in the laminating step, but has a higher melting point than the adhesive layer Since the collapse of the orientation in the layers is still insufficient, in the heating of the reheating step, by disrupting the orientation of these layers,
It is necessary to have good workability. Therefore, the heating temperature in the reheating step in the case of using a resin film having a plurality of layers is (Tm1-50) ° C or more and (Tm1 + 30) ° C based on the melting point Tm1 of the layer having the highest melting point.
It was determined to be within the range.

The structure of the present invention other than the above-mentioned heating temperature conditions in the case of using a resin film having a multilayer structure is the same as that in the case of using the resin film having a single-layer structure described above, and a description thereof will be omitted. .

The thermoplastic resin film may be a single-layer or multi-layer resin film containing a polyolefin resin, a polyester resin, a polyamide resin, or the like as a main component, a resin film obtained by blending two or more of these resins, or a copolymer. A resin film or the like can be used.

[0035]

Example 1 (2-layer film, no reheating step) A JIS A 5052 alloy rolled plate having a thickness of 0.5 mm was degreased with a weak etching type alkaline degreasing solution, and then subjected to a base treatment. For the invention examples, an aqueous solution containing a polyacrylic acid-based organic resin, phosphoric acid, and ammonium zirconium carbonate was applied, and heated at 110 ° C. for 5 hours.
A coating-type base treatment for drying for 2 seconds was performed. Application amount is 11
0.5 g / m ^{2 of the} total amount of the film after drying at 0 ° C. for 5 seconds, Zr
The amount was 10 mg / m ² . Also those same as Zr weight coating amount using an aqueous solution with reduced ammonium zirconium carbonate as a comparative example were subjected to a coating type surface treatment of 1 mg / m ^2, of 20 mg / m ² of Cr amount usual reactive phosphoric acid chromate Processed ones were also prepared.

A resin having a glass transition temperature of 72.degree. C. and a melting point of 215.degree.
A polyester film having a total thickness of 20 μm was formed by using a polyester having a glass transition temperature of 75 ° C. and a melting point of 260 ° C. and a thickness of 17 μm as a resin for the outer layer. T1 was coated with various changes, and then cooled immediately to produce a resin-coated aluminum plate.

When the condition of claim 3 is applied, the heating temperature T1 of the aluminum plate in the laminating step is 72 ° C. ≦ T1 ≦ 2
It will be 60 ° C.

As the cooling method, water cooling and standing cooling were employed.
The cooling rate of water cooling is 120 ° C / sec, and the cooling rate of cooling is 20
° C / sec.

The thus obtained resin-coated aluminum plate was subjected to a rolling process of 30% as a simulated forming process, and as an index of the adhesion between the resin film and the aluminum plate, the presence or absence of occurrence of peeling of the resin film and the processing of the resin film itself were determined. The film appearance was also examined as an index of the properties. The adhesion was evaluated as ○ when there was no peeling, and x when there was any peeling. Regarding the film appearance, those having neither whitening, roughening nor cracks were denoted by ○, and those having any of whitening, roughening and cracking were denoted as “whitening”, “roughness” and “crack”, respectively. The resin-coated aluminum plate after lamination and after 30% rolling is
A cas test of 24 hours was performed according to ISH 8681 to evaluate the corrosion resistance.も の indicates that no corrosion occurred, and x indicates that corrosion was observed even slightly. Table 1 shows processing conditions and evaluation results.

[0040]

[Table 1]

The test material No. Nos. 4 and 5 have been subjected to a normal reaction type phosphoric acid chromate treatment as a base treatment. The adhesion after lamination is good, and as a result, the corrosion resistance is excellent, but the adhesion during subsequent processing and the corrosion resistance after processing. Was inferior. Test material No. Sample No. 6 was inferior in adhesion and corrosion resistance because the amount of metal in the coating type base treatment was too small.
o. In the cases 7 and 8, cooling was adopted, so that the resin film was slightly whitened, and the adhesion and corrosion resistance were poor. In addition, the test material No. 9
Since the T1 temperature is too low, adhesion, workability, and corrosion resistance are poor. On the other hand, the test material No. 1, 2, and 3 showed good workability, adhesion, and corrosion resistance.

Example 2 (Single-layer film, with reheating step) An aluminum plate made of a JIS A 3004 alloy having a thickness of 0.5 mm was degreased with a weak etching type alkaline degreasing solution, and then subjected to a base treatment. For the invention examples, a coating-type base treatment in which an aqueous solution containing a polyacrylic acid-based organic resin, hydrogen fluoride, and chromium phosphate was applied and dried at 130 ° C. for 5 seconds was performed. Although the coating amount was changed, in the invention example, the total amount of the film was 0.4, 0.8, and 1.2 g.
/ M ² , and levels of 10, 20, and 30 mg / m ^{2 in} terms of the amount of Cr after drying. As a comparative example, the total amount of the coating was 0.4 g / m ² and the amount of Cr was 1 using an aqueous solution containing reduced chromium phosphate.
mg / m ² coated base treatment, Cr content 2
A product that had been subjected to a normal reactive phosphoric acid chromate conversion treatment at 0 mg / m ² was also prepared.

A polyethylene terephthalate film having a single-layer structure having a glass transition temperature of 80 ° C., a melting point of 264 ° C., and a thickness of 20 μm was applied to these base material plates at a heating temperature T1 of the aluminum plate in the laminating step and a resin film in the reheating step. Was changed at various temperatures T2, and then cooled immediately to produce a resin-coated aluminum plate.

According to the condition of claim 2, the heating temperature T1 of the aluminum plate in the laminating step is 80 ° C. ≦ T1 ≦ 2
64 ° C., the temperature T2 of the resin film in the reheating step is 2
14 ° C. ≦ T2 ≦ 294 ° C.

The cooling method, the simulated molding process, and the evaluation method are the same as those in the first embodiment. Table 2 shows processing conditions and evaluation results.

[0046]

[Table 2]

Sample No. Nos. 13 and 14 have been subjected to a conventional chemical conversion chromate treatment as a base treatment. The adhesion after lamination is good and as a result, the corrosion resistance is excellent, but the adhesion during processing and the corrosion resistance after processing are low. Inferior results. Test material No. No. 17 is a coating type base treatment, but the coating amount is too small, so that adhesion and corrosion resistance are poor. In Examples 18 and 19, cooling was adopted, so that the resin film was slightly whitened, resulting in poor adhesion and corrosion resistance. In addition, the test material No. Sample No. 20 was inferior in adhesion and corrosion resistance because the T1 temperature was too low. Sample No. 21 was inferior in adhesion, workability and corrosion resistance because the T2 temperature was too low.
o. In No. 22, since the T2 temperature was too high, the film was roughened and the corrosion resistance was poor. On the other hand, the test material No.
10, 11, 12, 15, and 16 exhibited good workability, adhesion, and corrosion resistance.

Example 3 (two-layer film, with a reheating step) A plate material subjected to the same undercoating treatment as in Example 2 was applied as a resin for the adhesive layer to a glass transition temperature of 72 ° C. and a melting point of 215 ° C. and a thickness of 5 mm.
A polyester film having a total thickness of 20 μm is coated using a polyester having a glass transition temperature of 75 ° C. and a melting point of 260 ° C. as a resin of the outer layer using a polyester having a thickness of 20 μm. The coating was performed by changing the heating temperature T1 of the resin film and the temperature T2 of the resin film in the reheating step, and then cooled immediately to produce a resin-coated aluminum plate.

When the conditions of claim 4 are applied, the heating temperature T1 of the aluminum plate in the laminating step is 72 ° C. ≦ T1 ≦ 2
60 ° C., the temperature T2 of the resin film in the reheating step is 2
10 ° C. ≦ T2 ≦ 290 ° C.

The cooling method, the simulated forming process, and the evaluation method are the same as those of the first and second embodiments. Table 3 shows processing conditions and evaluation results.

[0051]

[Table 3]

Sample No. Nos. 26 and 27 have been subjected to a conventional chemical conversion chromate treatment as a base treatment. Although the adhesion after lamination is good and the corrosion resistance is excellent as a result, the adhesion during the subsequent processing and the corrosion resistance after the processing are low. Inferior results. Test material No. No. 30 is a coating type base treatment, but the coating amount was too small, so that the adhesion and corrosion resistance were poor. Since cooling was adopted for 31 and 32, the resin film was slightly whitened, resulting in poor adhesion and corrosion resistance. In addition, the test material No. Sample No. 33 was inferior in adhesion and corrosion resistance because the T1 temperature was too low. In the sample No. 34, the T2 temperature was too low, so the adhesion, workability and corrosion resistance were poor.
o. In No. 35, since the T2 temperature is too high, the film is roughened and the corrosion resistance is poor. On the other hand, the test material No.
23, 24, 25, 28 and 29 exhibited good workability, adhesion and corrosion resistance.

[0053]

According to the method of the present invention, an aqueous solution containing an organic resin, metal ions and an acid is applied to an aluminum plate.
Since a drying base treatment step is provided and a lamination step at an appropriate temperature is provided, high adhesion and workability of the resin film can be obtained. Therefore, according to the method of the present invention, the adhesion of the resin film to the aluminum plate material is good, and the workability of the resin film itself is also excellent, and as a result, a coated aluminum plate having good corrosion resistance can be obtained reliably and stably. .

[Brief description of the drawings]

FIG. 1A is a schematic diagram showing an example of a conceptual configuration of a situation in which a method according to the second aspect of the present invention is performed;
(B) of the lower stage is a diagram showing a temperature transition of the aluminum plate and the resin film in each step corresponding to the configuration of (A).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum plate 5 1st heating means 7A, 7B Laminating roll 9A, 9B Thermoplastic resin film 11 2nd heating means (infrared heating method)

Claims (4)

[Claims] An aqueous solution containing an organic resin, a metal ion and an acid is dried on an aluminum plate after degreasing treatment in a total amount of 0.2 to 3 g / m ² after drying, and an amount of metal in the coating is 5 to 3 g / m ² .
A base treatment step of coating and drying to a concentration of 50 mg / m ² , followed by heating the aluminum plate to a temperature not lower than the glass transition temperature of the thermoplastic resin film and lower than the melting point (Tm); A laminating step of laminating a thermoplastic resin film on at least one surface of an aluminum plate at a temperature of 3 ° C. and pressing with a laminating roll, followed by quenching at a cooling rate of 40 ° C./sec or less below the glass transition temperature of the thermoplastic resin film A process for producing a resin-coated aluminum plate having excellent adhesion and workability, comprising the steps of: 2. The method according to claim 1, wherein the temperature of the resin film is (Tm−50) ° C. or more and (Tm + 3) between the laminating step and the cooling step.
The method for producing a resin-coated aluminum plate excellent in adhesion and workability according to claim 1, characterized by adding a reheating step of heating the temperature to 0 ° C or lower. 3. When using a thermoplastic resin film having a multilayer structure of two or more layers, the temperature of the aluminum plate in the laminating step is equal to or higher than the glass transition temperature of the resin film of the adhesive layer in contact with the plate, and the resin film of the outermost layer The method for producing a resin-coated aluminum plate excellent in adhesion and workability according to claim 1 or 2, wherein the temperature is not higher than the melting point. 4. When a thermoplastic resin film having a multilayer structure of two or more layers is used, the temperature of the aluminum plate in the laminating step is not lower than the glass transition temperature of the resin film of the adhesive layer in contact with the plate, and the resin film of the outermost layer Below the melting point of
In addition, according to the highest resin melting point (Tm1) of the layers constituting the film, the temperature of the resin film in the reheating step is reheated to (Tm1−50) ° C. or more and (Tm1 + 30) ° C. or less. 3. A method according to claim 1, wherein
3. The method for producing a resin-coated aluminum plate having excellent adhesion and processability described in 1. above.