JPS6210705B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a surface treatment method for a substrate for adhering an organic synthetic resin film or applying an organic paint to an aluminum or aluminum alloy product or material. Laminated products made by laminating aluminum or aluminum alloy foil with synthetic resin film or paper are in great demand in the food packaging field. However, aluminum or aluminum alloy foil has insufficient adhesion to paint or synthetic resin film, and when used in soft containers made using the above-mentioned laminates, for example to hold acidic contents such as fruit juice. However, there are disadvantages in that the aluminum or aluminum alloy foil and the paint or synthetic resin film peel off, and the aluminum or aluminum alloy corrodes and cannot be stored for a long period of time. Furthermore, food packaging bags that undergo high temperature sterilization after being filled with contents have an even shorter shelf life. Conventionally, anodic oxidation treatment, phosphoric acid treatment, chromate treatment, phosphoric acid treatment, boehmite treatment, etc. have been known as methods for improving the adhesion of aluminum to synthetic resins or paints. Alkaline cleaning (degreasing),
It requires many complicated cleaning steps, including acid cleaning, etc., and causes problems of environmental pollution by wastewater. In addition, in the accompanying processes such as alkaline cleaning and acid cleaning, anodizing treatment, boehmite treatment, etc., the treatment itself essentially involves dissolving aluminum, and therefore aluminum or aluminum alloy foil is essentially unavoidable. This has the undesirable effect of further enlarging the area of the pinhole. Furthermore, in alkaline cleaning and acid cleaning, aluminum is dissolved in the cleaning solution, so dissolved residue adheres to the aluminum alloy surface after cleaning, which affects the surface treatment in the next process, as well as the adhesion and corrosion resistance with synthetic resins or paints. often have a negative impact on This tendency is particularly remarkable when the type of surface treatment agent is a coating type surface treatment agent that does not require cleaning after treatment. Many attempts have been made to improve the adhesion with organic synthetic resin films and organic paints by treating the surfaces of aluminum, steel, etc., and alloys containing these as main components. ―62139
In this issue, a method is proposed in which the surface of aluminum or aluminum alloy is treated with a chemical conversion treatment solution containing a phosphate (or phosphoric acid) and a tannin metal salt (or a tannic acid metal salt). Also, the 1970s
No. 39232 discloses a method of treating the surface of steel, aluminum, etc. with a treatment liquid consisting of a soluble zirconium compound and a polymer. However, these conventional techniques have insufficient adhesion with organic synthetic resin films and organic paints, particularly when used in packaging materials subjected to high temperature sterilization (hereinafter referred to as adhesion). As a method to improve the above-mentioned shortcomings of the prior art, the inventors of the present application have previously developed a method for treating the surface of aluminum or aluminum alloy at 250 to 450°C until its surface tension reaches 46 dynes/cm or more.
We propose a treatment method in which the surface is heated to a temperature of , and then coated with a mixed aqueous solution containing (A) a water-soluble titanium compound and/or a water-soluble zirconium compound and (B) a tannin substance and/or an organic polymer substance and dried. (Special Application No. 1969-196995). Subsequently, new technologies such as those described below have been developed for packaging materials using aluminum or aluminum alloys, and there has been a demand for even improved adhesion. The tab opening piece of the conventional easy-open lid is
Because it has sharp edges, there is a serious problem that the fingers of those who handle it can be damaged, and the danger increases significantly if it is discarded at the beach where people often walk barefoot.In order to solve this problem, Easy-open lids (No. (See Figure 1)
(See No. 163642). In addition, in Fig. 1, 1 is a can lid,
2 is an opening piece, and 3 is an opening. When this lid is applied to canned goods that require sterilization, such as coffee drinks and shiruko, if the opening piece is made of conventional aluminum foil, the adhesion between the aluminum foil and the coating will decrease during heat sterilization. As a result, peeling occurs between the two, resulting in problems such as leakage of the contents of the can. Additionally, aluminum foil lids have recently been used for semi-rigid containers, such as packaging for water mush. Attempts have been made to give this lid an easy-open function, but unlike rigid can lids, the riveted process makes it impossible to attach a ring/pull tab, and the lid is made of pre-scored painted aluminum foil. An easy-open lid (see Figure 2) was devised in which a ring pull tab painted on the top was thermally bonded via adhesive (see JP-A-58-73541). In Figure 2, symbol 6 is the score (cut line), 7 is the painted aluminum lid, 8 is the ring/pull tab, 9 is the score torn open tip, 10 is the grip, and 11 is the ring/pull tab and the painted aluminum lid. The adhesive part is shown. Even with this lid, when it goes through the heat sterilization process, the adhesion between the aluminum foil and the coating decreases, resulting in the lid and ring pull tab coming apart and making it impossible to open. There was a strong need for this. The present invention provides a surface treatment method that solves the above-mentioned problems with aluminum foil, as well as the problems of reduced adhesion and corrosion resistance when cone cups are made from aluminum (alloy) foil by deep drawing. It is something to do. Previous proposal by the present inventors (Patent Application No. 196995-1987)
In this case, the adhesion is considerably improved, but especially in the case of aluminum alloys, magnesium is concentrated on the surface, so the adhesion is not necessarily sufficient, corrosion resistance is also reduced, and the hard aluminum becomes softer. That was later discovered. The disadvantage of softening is that the thickness of the aluminum foil must be increased to maintain the necessary strength. The present invention solves these problems associated with heat treatment and provides a surface treatment method for aluminum or aluminum alloy products or materials that has even better adhesion. Another object of the present invention is to provide a method for easily providing a laminate comprising an aluminum or aluminum alloy foil and an organic coating with improved corrosion resistance in a small number of steps. The purpose of the present invention is to subject the surface of a product or material made of aluminum or aluminum alloy to a corona discharge treatment until the surface tension becomes 46 dynes/cm or more, and then (A) remove water-soluble titanium compounds and water-soluble zirconium compounds from the surface of the product or material. (B) a mixture containing one or more tannin substances, one or more water-soluble or water-dispersible organic polymer substances, or both; This is accomplished by applying a surface treatment solution consisting of an aqueous solution to the aluminum surface and drying it. For the corona discharge treatment, a commonly used method is adopted, but preferably a commercially available high frequency generator is used, an insulated roller electrode or a flat plate electrode is used, the electrode voltage is 5KV to 30KV, and the frequency is 5KHz to 50K.
The aluminum surface can be subjected to corona discharge treatment by performing corona discharge at Hz and an inter-electrode distance of 1 to 5 mm. In the following description, foil will be described as an example of an aluminum or aluminum alloy product or material. Aluminum foil or aluminum alloy foil is suitable as the aluminum or aluminum alloy product or material used in the present invention. In the method of the present invention, the surface tension of aluminum or aluminum alloy foil after corona discharge treatment is
46 dyn/cm or more, preferably 50 dyn/cm or more, most preferably 60 dyn/cm or more,
When the surface tension is lower than this, the treatment liquid cannot uniformly wet the surface of the foil in the next step of surface treatment, making it impossible to obtain an excellent surface treatment film. The surface tension (γ _s ) of aluminum or aluminum alloy foil in the present invention is γ _s = γ _s ^d + γ _s ^p (where γ _s is the surface tension of the solid, γ _s ^d is the dispersion force component of the surface tension, γ _s ^p is the polar component of the same surface tension), and γ _s ^d and γ _s ^p are the surface tension γ _L of the liquid, the dispersion force component γ _L ^d of the same surface tension, and the polar component γ of the same surface tension. The contact angle θ was measured using two liquids with known _L ^p , distilled water and formamide, and the following formula was used:
(i) cosθ+1 = 2/γ _L (√ _L ^d _s ^d + √ _L ^p _s ^p ) (1) (“Physical Chemistry of Adhesion” David H. Kaelble, p. 158, Wiley- Interscience a Division of John Wiely & Sons, Inc. ). The surface tensions of the above test liquids, distilled water and formamide, are shown in the table below.

[Table] θ was measured according to the Aluminum Surface Treatment Technology Research Association standard, “ARS1831 Contact Angle Measurement” method.
Measured under conditions of temperature 23±2℃ and humidity 50±5%RH. Let γ s d and _γ sp, which are obtained by substituting the values _of each θ measured for both of the above test solutions and the values of γ _L , γ _L ^d , and γ _L ^p in the above table, into equation (1 ⁾ as unknowns ^. Find γ _s ^d and γ _s ^p from the two equations and obtain γ _s as their sum. In the present invention, organic synthetic resin films, organic paints, etc. Improves adhesion to coatings. The surface treatment liquid is an aqueous solution containing components selected from two groups, where one component (A) is selected from the group consisting of a water-soluble titanium compound and a water-soluble zirconium compound, and the other component (B) is one type. or selected from the group of two or more tannin substances, one or more organic polymer substances, or both. The organic polymer substance used is water-soluble or water-dispersible. Examples of water-soluble titanium compounds of component (A) include titanium hydrofluoric acid and its Na, K, or ammonium salts, and titanium sulfate, and examples of water-soluble zirconium compounds include zirconium hydrofluoric acid and its Na, K, and , or ammonium salts and ammonium zirconium carbonate. The above titanium compound and zirconium compound are used in a total amount of 0.01 to 5 g (metal equivalent), preferably 0.02 to 4 g per aqueous solution. The tannin substance of component (B) means tannin or tannic acid, examples of which include quebratillo, depujito, Chinese tannin, Turkish tannin, hamamelitannic acid, chebulic acid, sumac tannin, fivefold tannin, and erlagic acid tannin. It is. Examples of the organic polymer compound of component (B) are polymers or copolymers of acrylic acid and its esters such as methyl, ethyl and butyl esters, and polymers or copolymers of methacrylic acid and its esters such as methyl, ethyl and butyl esters. Polymers or copolymers, alkali metal and ammonium salts of polyacrylic acid or polymethacrylic acid or acrylic polymers or copolymers such as acrylamide; sodium alginate; polyvinylpyrrolidine; polyvinyl alcohol; polyvinyl methyl ether and ethylene-acrylic Acid copolymers, etc., and preferred examples include polymers of acrylic acid, copolymers of acrylic acid and its esters such as methyl, ethyl, butyl, etc., polymers of methacrylic acid, methacrylic acid and its methyl, It is a copolymer with esters such as ethyl and butyl. The amount of compound (B) to be used is 15g per aqueous solution for each tannin substance and organic polymer substance.
Below, preferably 10g or less, the total of both is at least 0.1g or more, preferably 0.3g or more. The processing liquid as exemplified above can be used in a roll coater,
It is applied onto the surface of aluminum or aluminum alloy foil by spraying or by dipping and then passing through a squeeze roll. The coating amount is 1 to 20 g/m ² , preferably 3 to 15 g/m ² based on the weight of the wet film. After coating, water is evaporated and dried by hot air drying or any other known drying method. If the weight of the wet film is less than 1g/ ^m2 , it is difficult to completely cover the metal surface;
Coating in an amount of 20 g/m ² or more is unnecessary and may cause the coating liquid to flow and cause unevenness, and also requires excessive drying equipment. There are no particular restrictions on aluminum or aluminum alloys suitable for treatment by the method of the present invention, and all aluminum and aluminum alloys specified in JIS H4000 and H4160 can be used. Products or materials having aluminum or aluminum alloy surfaces treated by the method of the present invention have excellent adhesion to paints, synthetic resin films, etc., and can be applied to packaging materials or containers, especially by coating or laminating them. Used for soft or semi-rigid containers such as bags and their lids, and especially for ring pull tabs and container lids when securing easy-open lid opening pieces and ring pull tabs with an easy-open function with adhesive. suitable for Particularly suitable paints include epoxy paints, phenol paints, amino resin paints, alkyd paints,
Polyester paints, vinyl chloride/vinyl acetate copolymers, organosol type paints, and acrylic paints.
These can be used alone or in combination of two or more. Particularly suitable synthetic resin films include films of homopolyesters such as polyethylene terephthalate and polybutylene terephthalate, copolyesters such as polyethylene terephthalate-isophthalate and polybutylene terephthalate-isophthalate, or blends thereof; Films of polyolefins such as high-density polyethylene, low-density polyethylene, or polypropylene, which can be used stretched or unstretched. The present invention will be explained in more detail with reference to Examples below. Examples Through each example, primary adhesion strength test, secondary adhesion strength test, heat sterilization test of tape heat seal lid,
An adhesive ring pull tab openability test and a draw cup corrosion resistance test were conducted as follows. 1 Primary adhesion strength test After reinforcing the back side of the test surface of the organic film-coated aluminum foil by adhering a 100 μm thick biaxially stretched polyester film using a urethane adhesive,
A test piece was cut out to a size of mm x 100 mm and the test surfaces were bonded together by heating using a nylon adhesive. However, in Examples 9 to 11, polyester was used without using adhesive.
A test piece was prepared by heat-bonding polyethylene or polypropylene together. The test piece was subjected to a T-peel test using a tensile tester at a tensile speed of 200 mm/min, and the peel strength was defined as the primary adhesion strength. 2 Secondary adhesion strength test A test piece prepared in the same manner as for primary adhesion strength measurement was immersed in tap water at 90°C for 4 days and then subjected to a T-peel test, and the peel strength was defined as secondary adhesion strength. 3 Heat sterilization test of tape heat seal lids After adhering 50 μm thick biaxially stretched polyester to the back side of the test surface of the painted aluminum foil prepared in the following Examples and Comparative Examples using a urethane adhesive, Cut into a rectangular shape with a length of 36 mm to make an opening piece. This opening piece was attached to a can lid (outer diameter 67 mm) made of electrolytic chromic acid-treated steel plate with epoxyphenol paint applied to the outside of the container.
A tape heat-sealed lid was manufactured by heat-sealing a 2-mm wide copolyester film around the 20-mm round opening so as to cover the opening. Next, 250 g of coffee beverage is filled into a 250 g can with an inner diameter of 52.3 mm, a tape heat seal lid is double-sealed, and heat sterilization is performed at 130° C. for 30 minutes. After 50 cans are tested and sterilized by heat, the evaluation is based on the number of cans that leaked from the opening of the tape heat seal lid. 4 Openability test of adhesive ring pull tab After a 50 μm thick polypropylene film was thermally bonded to the back side of the painted aluminum foil prepared in the following Examples and Comparative Examples (however, only the front surface was painted) via a modified polypropylene resin adhesive. , diameter 74mm
It was cut into a circle, and a score was placed on the painted surface along a position 5 mm from the outer periphery so that the thickness of the metal foil was approximately 35 μm to form a lid. An opening ring pull tab made of the same painted aluminum foil as the lid is thermally bonded to the painted surface of the lid using nylon adhesive so that the tearing tip is positioned on the score, allowing easy opening of the adhesive ring pull tab. I made a lid. After hot filling a 90 c.c. container with water oat, heat-sealing it with the lid, sterilize it by pressure heating at 120℃ for 60 minutes, and then store it at 50℃ for one month. 50 samples each
Individual tests are performed and evaluation is made based on the number of pieces that cannot be opened after storage. 5 Draw cup corrosion resistance test Organic film coated aluminum foil
14363, a cup with an inner diameter of 65 mmφ, a height of 30 mm, and a flange width of 3 mm is made by drawing from a blank size of 120 mmφ, and then filled with vinegar containing 3% salt at 80℃ to form an organic film with the same material composition as the cup. The lid of the coated aluminum foil is sealed by heat-sealing the flange portion with a nylon adhesive, and retort treatment is performed at 120°C for 20 minutes. However, Examples 9 to 11 were sealed by heat sealing copolyesters, polyethylenes, or polypropylenes without using an adhesive.
After storing this at 50°C for one week, remove the lid, visually observe the condition of the inner surface of the cup, and evaluate the results using the following 5-point method. 5: No abnormality 4: 1 to 5% of the aluminum surface is corroded and the organic film is peeled off. 3: 6-25% 〃 〃 2: 26-60% 〃 〃 1: 61-100% 〃 〃 Examples 1-4, comparatively 1-3 50 μm thick aluminum alloy foil A1N30H-
H18 was subjected to corona discharge treatment for the time shown in Table 1 under the conditions of an electrode spacing of 1 to 3 mm, an electrode voltage of 20 KV, and a frequency of 10 KHz, and the surface tension of the aluminum alloy surface was adjusted to the value shown in Table 1. However, in Comparative Example 2, the commercially available alkaline degreaser Ridrin 72N-1 (Nippon Paint
Comparative Example 3 is a comparative example in which the surface tension is not adjusted, and the surface tensions of each are shown in Table 1. It was hot on the street. The following surface treatment solution was applied to the surface of these aluminum alloy foils using a roll at a wet coating amount of 6 g/m ² and dried by heating at 150° C. for 5 seconds. The composition of the surface treatment liquid was as follows. Sodium zircon fluoride 3g Polyacrylic acid aqueous solution (average molecular weight 50000,
Non-volatile residue 25wt%) 5g Tannic acid (quintuple tannin) 0.1g Deionized water 1 Next, apply epoxy-phenol paint to a thickness of approximately 5μm after drying and baking at 250℃ for 30 seconds. did. The thus obtained coated aluminum foil was tested for primary adhesion strength, secondary adhesion strength, heat sterilization of the tape heat-sealed lid, and openability of the adhesive ring pull tab. The results are shown in Table 1. Example 5 Aluminum alloy foil A3004H-O with a thickness of 60 μm
Electrode spacing 1~3mm, electrode voltage 20KV, frequency
Corona discharge treatment for 0.5 seconds at 10KHz condition,
The surface tension of the aluminum alloy foil surface is 66.0dyn/
After that, the surface treatment liquid was sprayed onto the surface of the aluminum foil, the wet coating amount was adjusted to 7 to 10 g/m ² using a squeezing roll, and it was dried at 170° C. for 3 seconds. The composition of the surface treatment liquid was as follows. Sodium titanium fluoride 5g Tannic acid (quintuple tannin) 0.3g Polyacrylic acid aqueous solution (average molecular weight 60,000,
(Non-volatile residue: 25wt%) 8g Deionized water 1 Further, apply epoxy-phenol paint on the surface treated above so that the thickness after drying and baking becomes approximately 5μm, and drying and baking at 250℃ for 30 seconds. did. The thus obtained coated aluminum foil was tested for primary adhesion strength, secondary adhesion strength, and draw cup corrosion resistance. The results are shown in Table 2. Example 6 Corona discharge treatment time of aluminum alloy foil 0.4
sec, the surface tension is 64.2 dyn/cm, and the composition of the treatment solution is: Titanium ammonium fluoride 1.5g ((NH ₄ ) ₂ TiF ₆ ) Zirconium ammonium fluoride 1.0g ((NH ₄ ) ₂ ZrF ₆ ) Polyacrylic acid aqueous solution (Average molecular weight 50000,
The results shown in Table 2 were obtained in the same manner as in Example 5 except that the non-volatile residue was changed to 5 g deionized water 1 %. Example 7 A3004H-H18 as aluminum alloy foil, corona discharge treatment time 0.9 seconds, surface tension 60.2 dyn/
cm, and the composition of the treatment solution was changed to 0.5 g of sodium zirconium fluoride, 0.5 g of sodium titanium fluoride, 1 g of tannic acid (quintuple tannin), 1 g of deionized water, and the results shown in Table 2 were obtained. Ta. Example 8 The results shown in Table 2 were obtained in the same manner as in Example 7, except that the composition of the treatment solution was changed to 1.5 g of sodium titanium fluoride, 1 g of tannic acid (quintuple tannin), 5 g of aluminum phosphate, and 1 part of deionized water. Example 9 Aluminum alloy foil A5052H-H18 with a thickness of 100 μm
Electrode spacing 1~3mm, electrode voltage 20KV, frequency
Corona discharge treatment was performed for 0.8 seconds at 10KHz to adjust the aluminum alloy surface tension to 58.1dyn/cm.
The surface treatment liquid was applied with a roll to a wet coating amount of 7 g/m ² and dried at 150° C. for 5 seconds.
The composition of the surface treatment liquid was as follows. Sodium titanium fluoride 1g Tannic acid (quintuple tannin) 1g Aluminum phosphate 5g Deionized water 1 Next, a 30μm copolyester film was heated at 220℃.
It was heat laminated. The organic synthetic resin film-coated aluminum foil thus obtained was tested for primary adhesion strength, secondary adhesion strength, and draw cup corrosion resistance. The results are shown in Table 2. Example 10 Example 9 except that a 50 μm polyethylene film was used for the organic synthetic resin film coating, and this was thermally laminated onto a surface-treated aluminum alloy foil using a modified polyethylene adhesive.
The results shown in Table 2 were obtained in the same manner as above. Example 11 Table 2 was carried out in the same manner as in Example 9, except that a 50 μm polypropylene film was used for the organic synthetic resin film coating, and this was thermally laminated onto the surface-treated aluminum alloy foil via a modified polypropylene adhesive. The results shown are obtained. Comparative example 4 Aluminum alloy foil A3004H-O with a thickness of 60 μm
was degreased using a commercially available alkaline degreaser Ridrin 72N-1 (manufactured by Nippon Paint Co., Ltd.) at 70°C for 1 minute and washed with water. (The surface tension at this time is 63.2dyn/cm
It was hot. ), then immersed in an aqueous solution with the following composition at 60°C for 60 seconds, washed with water, and dried. Tannic acid (quintuple tannin) 1g First ammonium phosphate 1g 75% phosphoric acid 1.2g Sodium titanium fluoride 1g Dissolve the above ingredients in 1 part water. PH2.6 Next, an epoxy-phenol paint was applied and baked in the same manner as in Example 5, and the same tests as in Example 5 were conducted to obtain the results shown in Table 2. Comparative example 5 Aluminum alloy foil A3004H-O with a thickness of 60 μm
Acidic cleaning liquid Ridrin 419 (manufactured by Nippon Paint Co., Ltd.)
for 1 minute at 77°C (the surface tension at this time is
It was 60.7 dyn/cm. ), then zirconium oxide
2.0g/, polyacrylic acid aqueous solution (average molecular weight
60000, non-volatile residue 25 wt%) in an aqueous composition of 2.8 g/ml, and then dried. Next, an epoxy-phenol paint was applied and baked in the same manner as in Example 5, and the same tests as in Example 5 were conducted to obtain the results shown in Table 2. Comparative Example 6 The results shown in Table 2 were obtained in the same manner as in Example 5, except that 8 g of polyacrylic acid aqueous solution (average molecular weight 50,000, non-volatile residue 25 wt%) was dissolved in deionized water (1) to prepare a surface treatment solution. Ta. Comparative Example 7 The results shown in Table 2 were obtained in the same manner as in Example 5, except that 1 g of tannic acid (quintuple tannin) was dissolved in 1 deionized water to prepare a surface treatment solution. Comparative Example 8 The results shown in Table 2 were obtained in the same manner as in Example 5, except that the composition of the treatment liquid was changed to 0.5 g of sodium titanium fluoride, 0.5 g of sodium zirconium fluoride, and 1 part of deionized water. Comparative Example 9 The results shown in Table 2 were obtained in the same manner as in Example 5, except that the surface treatment with the treatment liquid was not performed. Comparative Example 10 Aluminum alloy foil after corona discharge treatment was treated at 60℃ using a treatment bath with the following composition: chromic anhydride (CrO ₃ ) 4g phosphoric acid (75%) 12g sodium fluoride (NaF) 3g deionized water 1 The results shown in Table 2 were obtained in the same manner as in Example 5, except that the sample was treated with phosphoric acid chromic acid for 30 seconds, washed with water, and dried. Comparative Example 11 Aluminum alloy foil after corona discharge treatment,
The results shown in Table 2 were obtained in the same manner as in Example 5, except that the sample was immersed in deionized water containing 0.3% by weight of triethanolamine at 100° C. for 1 minute, treated with boehmite, washed with water, and dried. Comparative Example 12 Aluminum alloy foil after corona discharge treatment was
The results are shown in Table 2 in the same manner as in Example 5, except that the anodization treatment was carried out in deionized water containing sulfuric acid at a current density of 1.5 A/dm ² and a temperature of 20° C. for 2 minutes, followed by washing with water and drying. Got the results. From Examples 1 to 4 and Comparative Examples 1 and 3, when the surface tension of the aluminum alloy foil is 46 dyn/cm or more, the primary adhesion strength, secondary adhesion strength, heat sterilization resistance of the tape heat seal lid, and adhesion are lower than those with a surface tension of 46 dyn/cm or more. It can be seen that the ring pull tab has excellent opening properties. From Examples 1 to 4 and Comparative Example 2, the surface tension of aluminum alloy foil was determined by alkaline degreasing.
60 dyn/cm or more, and the primary adhesion strength and secondary adhesion strength are close to those obtained by corona discharge treatment. Differences emerged when the pull tab opening test was conducted, and it is clear that corona discharge treatment has less variation in product characteristics than alkaline degreasing. From Examples 5 to 8 and Comparative Examples 6 to 7, the surface tension of the aluminum alloy foil was 46 dyn/cm or more, and a water-soluble titanium compound, a water-soluble zirconium compound, or both of them, tannic acid, and a water-soluble organic polymer compound were used. or a surface treatment solution containing both of them is applied and dried, a water-soluble titanium compound,
a water-soluble zirconium compound or both;
It can be seen that this surface treatment solution is superior to a surface treatment solution using only a tannin substance or a water-soluble organic polymer compound only in terms of primary adhesion, secondary adhesion, and corrosion resistance after drawing. Examples 9 to 11 show that the aluminum alloy foil of the present invention has a surface tension of 46 dyn/cm or more, and contains a water-soluble titanium compound, a water-soluble zirconium compound, or both of them, tannic acid, a water-soluble organic polymer compound, or both of them. When coated with an organic synthetic resin film such as polyester film, polyethylene film, or polypropylene film, products coated with a surface treatment liquid containing I understand. Examples 5 to 8 and Comparative Examples 9 to 12 show that the aluminum alloy foil of the present invention has a surface tension of 46 dyn/cm or more, and a water-soluble titanium compound, a water-soluble zirconium compound, or both of them, tannic acid, and a water-soluble organic polymer Materials coated and dried with a surface treatment solution containing a molecular compound or both are not only superior to untreated materials, but also superior to conventional phosphochromic acid treatment and boehmite treatment. I understand that. From Examples 5 to 8 and Comparative Examples 4 and 5, the aluminum alloy foil of the present invention was treated with corona discharge to have a surface tension of 46 dyn/cm or more, and a water-soluble titanium compound, a water-soluble zirconium compound, or both of them and tannic acid, a water-soluble The surface treatment liquid containing organic polymer compound or both of them is coated and dried.
Aluminum alloy foil is degreased with alkali, then immersed in a surface treatment solution containing tannic acid, ammonium phosphate, 75% phosphoric acid, and titanium fluoride soda, washed with water, and dried; It can be seen that the secondary adhesion and corrosion resistance after drawing are superior to those obtained by coating and drying a surface treatment liquid containing zirconium oxide and polyacrylic acid. Comparative Example 4 differs from the present invention in that alkaline degreasing is performed in the pretreatment and that primary ammonium phosphate and 75% phosphoric acid are added to the surface treatment solution. The difference between the invention and the pretreatment is that acid cleaning is performed, and in the present invention, the aluminum alloy foil is treated with corona discharge to have a surface tension of 45 dyn/cm or more, and in addition, water-soluble titanium compound, water-soluble zirconium It can be seen that an important technique is to apply and dry a surface treatment liquid containing the compound or both, tannic acid, a water-soluble organic polymer compound, or both. From Examples 1 to 11 and Comparative Examples 2, 4, 5, and 9, if the surface tension of the aluminum or aluminum alloy surface is adjusted to 46 dyn/cm or more by corona discharge treatment, aluminum alloy foil of any composition can be used. It can be seen that by applying the surface treatment of the invention, a surface-treated aluminum alloy foil having excellent primary adhesion, secondary adhesion, and processing corrosion resistance can be obtained.

【table】

【table】

【table】 [Brief explanation of the drawing]

Figure 1 is a perspective view of a can lid with an opening piece made of aluminum foil attached to which the surface treatment method of the present invention is applied, and Figure 2 is a perspective view of a can lid to which the surface treatment method of the present invention is applied. FIG. 3 is a plan view of the easy-open lid with the lid and ring pull tab attached via adhesive.

Claims (1)

[Claims] 1. After subjecting the surface of a product or material made of aluminum or aluminum alloy to corona discharge treatment until its surface tension becomes 46 dynes/cm or more, (A) a water-soluble titanium compound and a water-soluble zirconium compound. and (B) one or more tannin substances, one or more water-soluble or water-dispersible organic polymer substances, or both. 1. A method for treating the surface of an aluminum or aluminum alloy product or material, comprising applying a surface treatment liquid consisting of a mixed aqueous solution to the surface and drying it. 2. The method according to claim 1, wherein the aluminum or aluminum alloy material is aluminum or aluminum alloy foil. 3. The method according to claim 1, wherein the titanium compound is titanium hydrofluoric acid, its sodium, potassium, or ammonium salt; or titanium sulfate. 4. The method according to claim 1, wherein the zirconium compound is zirconium hydrofluoride, its sodium, potassium, or ammonium salt; or ammonium zirconium carbonate. 5. The method according to claim 1, wherein the titanium compound and the zirconium compound are contained in a total concentration of 0.01 to 5 grams (metal equivalent) per liter of the surface treatment solution. 6. The method according to claim 1, wherein the tannin substance is tannin or tannic acid. 7. The tannin substance and the water-soluble or water-dispersible organic polymer substance are each contained in an amount of 15 g or less per liter of treatment liquid, and at least one of them is
The method according to claim 1, wherein the amount is 0.1 g or more.