JPH1191034A - Surface-treated aluminum laminate with excellent barrier properties - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-treated aluminum laminate with excellent barrier properties for suppressing a manufacturing cost by preventing occurrence of feathering with excellent adhesive properties of a resin film without using chromium and preventing loss of flavorfulness of content due to metal component eluted from a film defective part due to processing such as forming. SOLUTION: The surface-treated aluminum laminate with excellent barrier properties comprises a sulfuric acid anodized film having a thickness of 100 to 15000 Angstrom on at least one side surface of aluminum or aluminum alloy material, and a thermoplastic resin film press-bonded to a surface of the anodized film in such a manner that mean surface roughness Ra of the anodized film is 0.01 to 0.1 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated aluminum laminate suitable as a lid material for aluminum cans for storing foods, especially two-piece cans for storing beverages such as soft drinks and alcoholic beverages. It is possible to prevent the loss of the flavor of the content due to the metal components eluted from the defective part of the film due to processing such as molding, and to reduce the production cost without using a resin film. The present invention relates to a surface-treated aluminum laminate excellent in barrier properties that can be suppressed.

[0002]

2. Description of the Related Art In recent years, surface-treated aluminum materials for two-piece cans for storing beverages have been applied to both the inner and outer surfaces of aluminum or aluminum alloy materials in terms of good preservability, easy processing, and beautiful appearance. A method of laminating a resin film to form a surface-treated aluminum laminate is widely used. In this type of surface-treated aluminum laminate, aluminum or an aluminum alloy material is subjected to a phosphoric acid chromate treatment for the purpose of improving the adhesion and corrosion resistance of the resin film.

A conventional surface-treated aluminum laminate for a two-piece can is manufactured, for example, as follows. First, a pretreatment is performed on an aluminum or aluminum alloy material. The pretreatment may be any as long as it can remove oils and fats adhering to the surface of the aluminum material and remove a heterogeneous oxide film on the surface of the aluminum material, and alkali etching or the like is appropriate. Then, the aluminum material is immersed in a bath solution mainly containing phosphoric acid, chromic acid, and fluoride, or the bath solution is sprayed on the surface of the aluminum material to form a thin gel on the surface of the aluminum material. An amorphous film of phosphoric acid chromate (hereinafter referred to as phosphoric acid chromate film) is formed. Then, when a resin film is laminated on one or both surfaces of the surface-treated aluminum material subjected to the phosphoric acid chromate treatment, a surface-treated aluminum laminate for a two-piece can is obtained. As a method of laminating the resin film here,
The surface-treated aluminum material is heated to a temperature close to or above the melting temperature of the resin film, the resin film is supplied on the heated material, and the resin film is pressed on the aluminum material using a pressure roll or the like. A heat fusion lamination method for fusing is adopted. In order to produce a two-piece can from the surface-treated aluminum laminate thus obtained, a lid for the surface-treated aluminum laminate is provided with a mold for attaching an open-tab, and then the open-tab is attached. In this manner, a lid is obtained, and on the other hand, a body is formed by drawing, bending, overhanging, and screwing the body material made of the surface-treated aluminum laminate, to obtain a can main body. And a bottom portion made of a surface-treated aluminum laminate, thereby obtaining an intended two-piece can.

[0004]

However, when a conventional surface-treated aluminum laminate is used as a lid for a two-piece can having an opening tab, a resin is not applied when a mold for attaching the opening tab is applied. If the film is damaged and a film defect may occur, and the phosphoric acid chromate film itself located below this defect may also be damaged, resulting in a thin part or a film defect was there. In the case where the resin film or the phosphate chromate film has deficient portions as described above, the beverage or the like that has entered from these deficient portions comes into contact with the phosphate chromate film or the aluminum material, and the metal component is eluted. Therefore, the phosphate chromate film has insufficient barrier properties as a film for protecting the aluminum material. Further, chromium used for the phosphoric acid chromate treatment is environmentally unfavorable, and may become unusable in the future due to increasing awareness of environmental issues in recent years. Therefore, various non-chromium-based treatment agents have been developed as an alternative to the phosphoric acid chromate treatment, but all of these treatment costs are high, and as a result, the production cost of the can is high. Not practical. In addition, because the resin film does not sufficiently satisfy the adhesiveness required as a lid material, when the can is opened, the resin film peels around the open tab and a feather-like shape called feathering. Peeling occurs
Furthermore, when this peeling occurs significantly, there is a problem that the resin film extends and is not cut, making it difficult to open the can.

The present invention has been made in view of the above circumstances, and does not use chromium, has excellent adhesion of a resin film, can prevent occurrence of feathering, and has a film defect due to processing such as molding. It is an object of the present invention to provide a surface-treated aluminum laminate excellent in barrier properties that can prevent the flavor property of the contents from being impaired due to a metal component eluted from a part, and can keep production costs low. .

[0006]

SUMMARY OF THE INVENTION The inventor of the present invention has proposed an aluminum or aluminum alloy material which does not use chromium, has sufficient adhesion of a resin film, can protect a base metal even in a defective portion of the film, and has a low processing cost. In order to investigate the surface treatment of anodic oxide film formed using boehmite film, sulfuric acid, oxalic acid, chromic acid solution as a candidate, and evaluated the barrier properties of the film, the anode formed using sulfuric acid solution The oxide film (hereinafter referred to as a sulfuric acid anodic oxide film) is a colorless and transparent film, so that the appearance quality is good, and since it is harder than the phosphate chromate film, it shows good durability and barrier properties, while the boehmite film is Anode formed by using oxalic acid or chromic acid solution due to the film itself being damaged at the film defect portion due to processing and having poor barrier properties. Of film was found that appearance is not preferable because a colored coating exhibit good barrier properties. Therefore, the present inventor studied more preferable conditions for the sulfuric acid anodized film. Since the sulfuric acid anodized film is a colorless and transparent film, a thick film causes interference colors and requires a long time for production. It is not suitable for low cost processing. On the other hand, when the film is made into a thin film, it is difficult to apply uniform treatment to the aluminum or aluminum alloy material, and the barrier property is insufficient because the durability against damage when the film is damaged is reduced. Therefore, as a result of examining an appropriate film thickness of the sulfuric acid anodic oxide film, it was found that a film having a film thickness of 100 to 1500 angstroms can provide good barrier properties and a film suitable for low cost processing can be obtained. It was done.

[0007] was examined for surface roughness of the sulfuric acid anodized film and the depth of the pore (hole) formed in an average surface roughness R _a and sulfuric acid anodized film are correlated, R _a
Is too large, and even if the pores (holes) formed in the sulfuric acid anodized film become too deep, an increase in the adhesion of the resin film cannot be expected. On the other hand, when R _a is too small,
The penetration of the resin film into the pores becomes shallow,
Anchor effect cannot be expected. Therefore, as a result of examining the appropriate average surface roughness of the sulfuric acid anodic oxide film, it was found that good resin film adhesion was obtained when _Ra was 0.01 to 0.1 μm, and that occurrence of feathering could be prevented. The present invention has been completed.

That is, the invention according to claim 1 is characterized in that a sulfuric acid anodic oxide film is provided on at least one surface of an aluminum or aluminum alloy material, and a thermoplastic resin film is pressed on the surface of the anodic oxide film. A surface-treated aluminum laminate excellent in barrier properties, characterized in that the oxide film has a thickness of 100 to 1500 angstroms, is a means for solving the above problem. Also,
According to a second aspect of the invention, the average surface roughness R _a of the anodized film, surface treated aluminum laminate excellent in barrier properties of claim 1, wherein it is 0.01~0.1μm Is a means for solving the above problem.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a surface-treated aluminum laminate excellent in barrier properties of the present invention will be described in detail. The surface-treated aluminum laminate of the present invention has a sulfuric acid anodic oxide film (sulfate anodized film) on at least one surface of an aluminum or aluminum alloy material.
Are formed, and a thermoplastic resin film is pressed on the surface of the sulfuric acid anodized film. As the aluminum or aluminum alloy material used in the present invention, Al-Mn 30
Although a 00-based alloy and an Al-Mg-based 5000-based alloy are used, they are not particularly limited from the spirit of the present invention, and various rolled sheets are applied. Further, alloys subjected to various refining treatments such as solution treatment and aging treatment are also used. Further, a clad material clad on the surface of these aluminum alloys can also be used. In the present invention, among these alloys, those of 5000 series used as a lid material for aluminum two-piece cans are preferable.

[0010] Pretreatment is performed on such a material. The pre-treatment is not particularly limited, and any material may be used as long as it can remove fats and oils adhering to the surface of the material and remove a heterogeneous oxide film on the surface of the material. For example, after performing a degreasing treatment with a weak alkaline degreasing solution, a method of performing a desmut treatment in a nitric acid aqueous solution after performing an alkali etching with a sodium hydroxide aqueous solution, and a method of performing acid cleaning after the degreasing treatment are appropriately selected. Used. In addition, the surface is roughened to the extent that the material is not colored by the active etching simultaneously with the degreasing, thereby increasing the anchor effect. As the etching here, alkali etching with sodium hydroxide or the like, acid etching with sulfuric acid, hydrofluoric acid, or the like, and etching by electrolysis in an acidic solution such as nitric acid can be used.

Then, the pretreated material is subjected to an anodic oxidation treatment for electrolysis in an electrolyte solution to form a sulfuric acid anodic oxide film on the surface of the material. The anodizing treatment can be performed on a material that has been subjected to processing such as press working, but is preferably performed continuously on unprocessed aluminum or aluminum alloy. This is because the oxidation treatment can be quickly performed on a large amount of the material.

As the electrolytic solution, there is used a sulfuric acid solution which is an electrolyte which hardly dissolves the formed anodic oxide film and forms a porous anodic oxide film. The concentration of the sulfuric acid solution is
10-20 vol% is preferable. The concentration of sulfuric acid solution is 10
When the concentration is lower than 10%, the bath voltage becomes high, an anodized film (alumite film) is hardly formed, and pits are easily generated. On the other hand, when the concentration exceeds 20%, an alumite film is formed. This is because the bath has a high dissolving power and the film formation rate may be poor. The bath temperature of the electrolytic bath is preferably in the range of 10C to 30C, more preferably 15C to 20C. If the bath temperature is lower than 10 ° C., the bath voltage is increased and the number of holes is reduced, but the lightness is reduced and the color becomes gray. On the other hand, when the bath temperature exceeds 30 ° C., the chemical dissolving power of the bath increases, and the generation rate of the alumite film decreases. In this electrolytic bath, the aluminum or aluminum alloy material is connected to a power source and electrolyzed so as to serve as an anode even if it is continuous or intermittent. An insoluble conductive material is used for the cathode.

As the electrolytic current, a direct current is used. In direct current electrolysis, the direct current density is approximately 0.5 to ^{2 A} / dm ² . If the current density is less than 0.5 A / dm ^2, it takes a long time to form a film, and it is not possible to rapidly and continuously electrolyze an aluminum or aluminum alloy material. On the other hand, 2A /
When it exceeds dm ² , surface defects such as a film and a burn easily occur. The electrolysis time is about 2 to 30 seconds, and the electrolysis is performed by selecting according to the desired film thickness and electrolysis conditions. The thickness of the sulfuric acid anodic oxide film is adjusted by the electrolysis time. The applied voltage is determined by the concentration and type of the electrolytic solution and the current density. Hole depth and the average roughness R _a of the surface of the sulfuric acid anodized film may be adjusted by electrolysis voltage, for example, to increase the hole depth is processed by lowering the electrolytic voltage.

By such an anodic oxidation treatment, a sulfuric acid anodic oxide film having a uniform thickness is formed on the surface of the material. The thickness of the sulfuric acid anodic oxide film is 100 to 1500 angstroms, preferably about 200 to 600 angstroms. When the film thickness is less than 100 angstroms,
It is difficult to apply uniform treatment to aluminum or aluminum alloy material, and the barrier property is insufficient because the durability against damage at the time of film loss is reduced, and when a film defect is caused by processing such as molding. In addition, corrosive beverages and the like may enter from the defective portion of the film to corrode and elute the underlying aluminum, thereby impairing the flavor of the contents. On the other hand, when the film thickness is 15
If the thickness exceeds 00 angstroms, an interference color is generated, which is not preferable in terms of appearance quality, and a long time is required for manufacturing, resulting in an increase in manufacturing cost.

On the surface of the sulfuric acid anodic oxide film thus obtained, pores (holes) are formed, and the surface is provided with irregularities. If irregularities are formed on the surface of the sulfuric acid anodic oxide film in this way, when the thermoplastic film is pressed on the surface of the sulfuric acid anodic oxide film, the thermoplastic resin film can bite into these irregularities, so the anchor The effect is enhanced, and the adhesiveness of the thermoplastic resin film can be improved. The average surface roughness _Ra varies depending on the depth of the pores on the surface of the sulfuric acid anodic oxide film,
A preferable average surface roughness _Ra is 0.01 to 0.1 μm.
m. The average surface roughness R _a of sulfuric acid anodized film
Is less than 0.01, it becomes difficult for the thermoplastic resin film to enter the pores, an anchor effect cannot be expected, and the adhesion of the resin film decreases. On the other hand, the average surface roughness R _a of sulfuric acid anodized film is larger than 0.1 [mu] m, even pores too deep, increase the adhesion of the resin film can not be obtained.

As the thermoplastic resin film used in the present invention, a material which can be press-bonded to the surface of the above-mentioned sulfuric acid anodic oxide film by thermal fusion is used, and polyethylene terephthalate (PET), PET / isophthalate, PET / adipate, poly Polyester film containing butylene terephthalate / isophthalate, polyethylene naphthalate, polyethylene naphthalate / terephthalate, or 50 mol% ethylene terephthalate unit
Occupying the above, copolymerized polyester film copolymerized with glycols and dicarboxylic acids, low density polyethylene,
Polyolefin films such as medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ion-crosslinked olefin copolymer (ionomer), ethylene-acrylate copolymer, and PET are exemplified. The thickness of the thermoplastic resin film is 9 to 20 μm.
m. If the thickness of the resin film exceeds 20 μm, the film will peel off or feathering will occur.

In order to press a thermoplastic resin film on an aluminum or aluminum alloy material (hereinafter referred to as a surface-treated aluminum material) on which a sulfuric acid anodic oxide film is formed, two sheets of heat are applied between a pair of heated press rolls. The thermoplastic resin film is sent out, and on the other hand, the two thermoplastic resin films sent out between the pair of pressure rolls while heating the surface-treated aluminum material by a heat roll near or above the melting temperature of the thermoplastic resin film In this case, the surface-treated aluminum material may be sandwiched between the thermoplastic resin films and thermally fused under pressure. In this way, a surface-treated aluminum laminate excellent in barrier properties, in which a thermoplastic resin film is laminated on both sides of the surface-treated aluminum material, can be obtained. Here, the temperature of the pressure-bonding roll is sufficient to keep the temperature of the heat-insulating roll.
The temperature when T is used is about 80 ° C. The temperature of the heat roll may be any temperature at which the surface-treated aluminum material can be heated to a temperature close to or above the melting temperature of the thermoplastic resin film, and the temperature when PET is used as the thermoplastic resin film is about It is about 220-260 ° C. The temperature of the heat roll differs depending on the type of PET used. Also,
The linear pressure applied by the roll is appropriately determined depending on the material and thickness of the thermoplastic resin film. Lamination can also be performed by a heat press or the like in addition to the pressure roll. The heat-sealing lamination method described here has been described in the case where a thermoplastic resin film is bonded to the surfaces of the sulfuric acid anodic oxide films on both surfaces of the surface-treated aluminum material, respectively. When an oxide film is formed, a thermoplastic resin film is pressed only on the sulfuric acid anodic oxide film side.

In the surface-treated aluminum laminate of the present invention, a sulfuric acid anodic oxide film having a thickness of 100 to 1500 angstroms is provided on at least one surface of the aluminum or aluminum alloy material, and the surface of the anodic oxide film is further thermally treated. Since the thermoplastic resin film is pressure-bonded, even in the unlikely event that a defect occurs in the thermoplastic resin film due to processing such as molding and a corrosive beverage or the like intrudes from the defect, the above sulfuric acid anode can be used. The oxide film has sufficient uniformity of the film and is harder than the conventional phosphoric acid chromate film, so it has excellent durability against damage when the film is damaged. The flavor property can be prevented from being impaired, and the barrier property is excellent. Further, by setting the thickness of the sulfuric acid anodic oxide film to 100 to 1500 angstroms, the sulfuric acid anodic oxide film itself is a colorless and transparent film, and the surface of the material is not colored due to light interference by the film. Also, since the appearance quality is good and the processing cost is not required, the manufacturing cost can be kept low. Further, since the sulfuric acid anodic oxide film is formed with irregularities due to pores on the surface, these irregularities can enhance the anchor effect with the thermoplastic resin film, and because the adhesiveness with the thermoplastic resin film is excellent, When the can having the can tab is opened, the feathering in which the thermoplastic resin film peels around the open tab does not occur, and the thermoplastic resin film does not extend and cannot be cut due to significant peeling. Therefore, opening of the can is easy. Further, since the sulfuric acid anodic oxide film formed in the present invention does not contain Cr, there is no environmental problem. Further, in the present invention, in particular, the average surface In the those in the range of 0.01~0.1μm roughness R _a, pore irregularities thermoplastic by the surface of the sulfuric acid anodized film of sulfuric acid anodized film The anchor effect with the resin film can be further improved, and the adhesion with the thermoplastic resin film can be further improved.

[0019]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to only these Examples. (Example 1) After using a JIS5183 alloy as an aluminum alloy and performing a degreasing treatment with a weak etching degreasing agent,
Electrolysis was performed with a sulfuric acid solution having a concentration of 15% at an applied voltage of 15 V, a current density of 1.5 A / dm ² and at 20 ° C. for 2 seconds to form a sulfuric acid anodic oxide film having a thickness of 100 Å on the surface of the aluminum alloy. After electrolysis, wash the alloy with water,
Drying was performed at 70 ° C. to obtain a surface-treated aluminum material.
Then, the two PET films are sent out between a pair of pressure rolls heated to 80 ° C., while the surface-treated aluminum material is heated to 200 to 230 ° C. by a heat roll heated to 260 ° C. By supplying between the two PET films sent out between the pair of pressure-bonding rolls, the surface-treated aluminum material is sandwiched between the PET films and thermally fused under pressure, so that both surfaces of the surface-treated aluminum material are A surface-treated aluminum laminate laminated with a PET film was obtained.
The thickness of the PET film used here was 10 μm.

(Example 2) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 20 V, a current density of 1.5 A / dm ² , 20 ° C.,
Electrolysis for 2 seconds, thickness 2 on the surface of aluminum alloy material
A sulfuric acid anodic oxide film of 00 Å was formed.
After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Example 3) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 20% was applied using a 15% sulfuric acid solution.
V, current density of 1.5 A / dm ² , electrolysis at 20 ° C. for 10 seconds to form a 500 angstrom thick sulfuric acid anodic oxide film on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Example 4) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 20% was applied using a 15% sulfuric acid solution.
V, a current density of 1.5 A / dm ² , electrolysis at 20 ° C. for 18 seconds was performed to form a 900 angstrom thick sulfuric acid anodic oxide film on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Example 5) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 20% was applied using a 15% sulfuric acid solution.
V, current density: 1.5 A / dm ² , electrolysis at 20 ° C. for 20 seconds to form a 1000 angstrom thick sulfuric acid anodic oxide film on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained.

(Embodiment 6) In the same manner as in Embodiment 1, aluminum
After degreasing the aluminum alloy, mark it with a 15% sulfuric acid solution.
Applied voltage 15V, current density 1.2A / dm^Two, 20 ° C, 8
Electrolysis for 2 seconds, thickness 3 on the surface of aluminum alloy material
10 angstrom, average surface roughness R _a0.01μ
m of sulfuric acid anodized film was formed. Example after electrolysis is completed
PE on both sides of surface treated aluminum material in the same manner as in 1.
Surface treated aluminum laminate with T film laminated
I got a board. (Example 7) An aluminum alloy was prepared in the same manner as in Example 1.
After degreasing, the applied voltage was 25% with a 15% sulfuric acid solution.
V, current density 2A / dm^TwoElectrolysis at 20 ° C for 7 seconds
And a thickness of 450 Å on the surface of the aluminum alloy material
In the tromes, the average surface roughness R_a0.01μm sulfuric acid anode
An oxide film was formed. After the electrolysis is completed, in the same manner as in Example 1,
PET film on both sides of surface treated aluminum material
A laminated surface-treated aluminum laminate was obtained.

Example 8 After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 15 V, a current density of 1.2 A / dm ² , 20 ° C.,
Electrolysis for 8 seconds, the thickness of the aluminum alloy material is 710 angstroms, the average surface roughness _Ra 0.05
A μm sulfuric acid anodic oxide film was formed. After the electrolysis is completed, P is applied to both surfaces of the surface-treated aluminum material in the same manner as in Example 1.
A surface-treated aluminum laminate laminated with an ET film was obtained. (Embodiment 9) After the aluminum alloy was degreased in the same manner as in Embodiment 1, the applied voltage was 25% with a 15% sulfuric acid solution.
V, current density: 2 A / dm ² , electrolysis at 20 ° C. for 13 seconds to form a sulfuric acid anodic oxide film having _a thickness of 850 Å and an average surface roughness _{Ra of} 0.05 μm on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained.

Example 10 An aluminum alloy was degreased in the same manner as in Example 1 and then treated with a 15% sulfuric acid solution.
Applied voltage 15 V, current density 1.2 A / dm ² , 20 ° C.,
Electrolysis is performed for 30 seconds, the thickness of the aluminum alloy material is 1210 Å, and the average surface roughness is _Ra 0.
A 1 μm sulfuric acid anodic oxide film was formed. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Example 11) After degreasing the aluminum alloy in the same manner as in Example 1, the applied voltage was 25% with a 15% sulfuric acid solution.
V, current density of 2 A / dm ² , electrolysis at 20 ° C. for 20 seconds to form a sulfuric acid anodic oxide film having _a thickness of 1350 Å and an average surface roughness _{Ra of} 0.1 μm on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained.

(Comparative Example 1) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 20 V, a current density of 1.5 A / dm ² , 20 ° C.,
Seconds of electrolysis, and a thickness of 9
A 0 angstrom sulfuric acid anodic oxide film was formed. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Comparative Example 2) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 20% was applied using a 15% sulfuric acid solution.
V, current density of 1.5 A / dm ² , electrolysis was performed at 20 ° C. for 32 seconds to form a 1600 angstrom thick sulfuric acid anodic oxide film on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Comparative Example 3) After the aluminum alloy was degreased in the same manner as in Example 1, an applied voltage of 20% was applied using a 15% sulfuric acid solution.
V, current density 1.5 A / dm ² , electrolysis at 20 ° C. for 36 seconds to form a sulfuric acid anodic oxide film having a thickness of 1800 angstroms on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained.

(Comparative Example 4) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 3 V, a current density of 0.2 A / dm ² , 20 ° C., 14
Seconds of electrolysis, and a thickness of 9
0 angstrom, average surface roughness _Ra 0.005μ
m of sulfuric acid anodized film was formed. After the completion of the electrolysis, both surfaces of the surface-treated aluminum material are
A surface-treated aluminum laminate laminated with a T film was obtained. (Comparative Example 5) After the aluminum alloy was degreased in the same manner as in Example 1, the applied voltage was 3 V with a 15% sulfuric acid solution.
Electrolysis was performed at a current density of 0.2 A / dm ² at 20 ° C. for 240 seconds to form a sulfuric acid anodic oxide film having _a thickness of 1600 Å and an average surface roughness _{Ra of} 0.005 μm on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Comparative Example 6) After degreasing the aluminum alloy in the same manner as in Example 1, an applied voltage of 15% was applied using a 15% sulfuric acid solution.
V, current density 1.2 A / dm ² , electrolysis at 20 ° C. for 43 seconds to form a sulfuric acid anodic oxide film having _a thickness of 1710 Å and an average surface roughness _{Ra of} 0.15 μm on the surface of the aluminum alloy material. . After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Comparative Example 7) After degreasing the aluminum alloy in the same manner as in Example 1, the applied voltage was 25% with a 15% sulfuric acid solution.
V, current density of 2 A / dm ² , electrolysis at 20 ° C. for 28 seconds to form a sulfuric acid anodic oxide film having _a thickness of 1850 Å and an average surface roughness _{Ra of} 0.15 μm on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained.

(Comparative Example 8) After degreasing the aluminum alloy in the same manner as in Example 1, the aluminum alloy was etched with a 10% aqueous sodium hydroxide solution at 50 ° C. for 2 minutes and washed with water.
After immersing in 10% nitric acid at room temperature for 1 minute and desmutting,
A bath solution of 55 ° C. in which a phosphoric acid chromate treating agent (trade name: Alodine) is dissolved is sprayed on an aluminum alloy for 3.0 to 3.5 seconds, then washed with water and dried at 60 ° C. to obtain 20 mg / m ^2. To obtain a surface-treated aluminum material on which a phosphoric acid chromate film having an adhesion amount of was formed. After the surface treatment, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Comparative Example 9) After degreasing the aluminum alloy in the same manner as in Example 1, the applied voltage was 25% with a 3% oxalic acid solution.
V, current density of 1 A / dm ² , electrolysis at 28 ° C. for 24 seconds to form an oxalic acid anodic oxide film having _a thickness of 1000 Å and an average surface roughness R _{a of} 0.01 μm on the surface of the aluminum alloy material. After the completion of the electrolysis, a surface-treated aluminum laminate in which PET films were laminated on both surfaces of the surface-treated aluminum material in the same manner as in Example 1 was obtained. (Comparative Example 10) An aluminum alloy was degreased in the same manner as in Example 1, and then subjected to electrolysis with a 10% chromic acid solution at an applied voltage of 30 V, a current density of 1 A / dm ² , 50 ° C. for 24 seconds, and aluminum A chromic acid anodic oxide film having _a thickness of 1000 angstroms and an average surface roughness R _{a of} 0.01 μm was formed on the surface of the alloy material. Example 1 after completion of electrolysis
PET on both sides of surface treated aluminum material
A surface-treated aluminum laminate laminated with a film was obtained.

(Experimental Examples) Examples 1 to 11 and Comparative Examples 1 to 1
The surface-treated aluminum laminate obtained in Step 0 was processed into can lids each having a can tab, and the PE when the can tab was opened was prepared.
The adhesion was evaluated by measuring the degree of the peel width of the T film. The results are shown in Tables 1 and 2 below. The evaluation criteria were as follows: (◎) not peeled, (○) peeled about 0 to 0.1 mm, (△) peeled about 0.1 to 0.5 mm, 0.6 mm or more peeled The sample was marked (x). Examples 1 to 11 and Comparative Examples 1 to 10
A pinhole was formed in the PET film of the surface-treated aluminum laminate obtained in the above, and processed into a can lid having a can tab, which was attached to a beverage can body having a bottom, and a liqueur was put therein and stored for 14 days. Later, the can was opened and the presence of aluminum odor was checked by taste to evaluate the flavor. The results are shown in Tables 1 and 2 below. The evaluation criterion was that the aluminum odor was not felt (○), the aluminum odor was slight (△), and the aluminum odor was clearly (x). Also,
The degree of coloring of the surface-treated aluminum materials obtained in Examples 1 to 11 and Comparative Examples 1 to 10 was evaluated by visually comparing the degree of coloring with an untreated aluminum material.
The results are shown in Tables 1 and 2 below. The evaluation criteria are as follows: those that are not different from the untreated aluminum material (coloring is not felt) (○), those that are slightly colored (△),
Those that clearly felt coloring were evaluated as (x).

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

As described above, in the surface-treated aluminum laminate having excellent barrier properties of the present invention, a sulfuric acid anodic oxide film having a thickness of 100 to 1500 Å is formed on at least one surface of an aluminum or aluminum alloy material. Since it is formed, a thermoplastic resin film is further pressed on the surface of the anodized film,
Without using chromium, the thermoplastic resin film has excellent adhesion and can prevent the occurrence of feathering.Furthermore, the flavor of the content is impaired due to aluminum eluted from the film defect due to processing such as molding. This has the advantage that the manufacturing cost can be kept low. In the present invention, in particular,
0.01 to 0 an average surface roughness R _a of the anodized film.
In the case of 1 μm, unevenness due to pores on the surface of the sulfuric acid anodic oxide film can further improve the anchoring effect with the thermoplastic resin film, and can further improve the adhesion with the thermoplastic resin film.

Claims (2)

[Claims] An anodic oxide film formed by using a sulfuric acid solution is provided on at least one surface of an aluminum or aluminum alloy material, and a thermoplastic resin film is pressed on the surface of the anodic oxide film. A surface-treated aluminum laminate excellent in barrier properties, characterized in that the thickness of the laminate is 100 to 1500 angstroms. 2. The average surface roughness R of the anodic oxide film
_The surface-treated aluminum laminate excellent in barrier properties according to claim 1, wherein _a is 0.01 to 0.1 µm.