JPS63151385A - Aluminum molding material with base film for coating - Google Patents

Abstract

PURPOSE:To increase adhesion with an ink without stripping-off by forming a dried film of an aqueous solution with dispersed polyolefin resin directly or through a metal contained resin film, as a base film for coating on an aluminum base. CONSTITUTION:A dried film 2 of a solution with dispersed polyolefin resin is formed on the surface of an aluminum base 1 such as beverage container or cap, as a base film for coating. This dried film 2 is formed by applying and drying a treatment solution of polyolefin resin which is a main component of a dispersion resin, and dispersed in an aqueous solution, in a film amount of 0.1mg/m<2> or more. However, in order to further improve adhesion and anti- corrosion properties, a metal-contained resin film 3 is interposed between the dried film 2 and the aluminum base 1. In this case, the film amount should be 0.5mg/m<2> or more. As a result, no sizing coat is required and the adhesion with printing ink or resin coat is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is applicable to moldings used for containers and caps for jelly, pudding, meat, vegetables, cooked foods, etc., and caps for containers for drinks, whiskey, juice, etc. The present invention relates to aluminum materials for molding, particularly aluminum materials for molding having a base film for resin coating, printing, etc.

In this specification, the term aluminum is used to include aluminum alloys.

BACKGROUND ART Food and beverage containers and caps, such as those described in "Prior Art and Problems Therewith", are generally made of aluminum material that is printed or coated with resin. Such printing and resin coating are applied to improve the appearance of containers and caps, or to prevent aluminum from being corroded by the contents of the containers.

However, such printing and resin coating have conventionally been applied after applying an undercoat called a size coat to the surface of the aluminum base material, which has the following drawbacks. In other words, the ink or paint film may peel off during the molding process, or the adhesion of the ink or paint film may deteriorate when retort sterilization is performed after filling the container with jelly, cooked food, drinks, etc. after molding. Moreover, there are also disadvantages in that the coating film may peel off due to the contents of the container during long-term storage, and the aluminum base material may corrode.

In addition, some users want to omit the size coat and apply printing or resin coating directly to the surface of the aluminum base material, but omitting the size coat will still result in peeling of the ink or coating film, so this requirement is not met. It was difficult to realize this.

On the other hand, in order to eliminate the drawbacks mentioned above, it is also known to coat the surface of an aluminum base material with a phosphoric acid monochromate film as a base film, and then apply resin coating or printing through the film. However, the adhesion of the paint film and ink was still insufficient. Furthermore, since the phosphoric acid-chromate film is an inorganic film, it also has the disadvantage of poor surface slipperiness. Further, the chromate treatment for forming the film is time-consuming and the phosphoric acid-chromate treatment solution is highly toxic, which poses problems in terms of work safety and waste liquid treatment.

This invention was made against this background, and by forming a new base film in place of the phosphoric acid-chromate film, it eliminates the need for a size coat and also reduces ink and paint film during retort processing. Not only can it prevent deterioration of adhesion, prevent peeling of the paint film due to contents during long-term storage of food products, and prevent corrosion of aluminum substrates, but it also has excellent adhesion with printing ink and painted resin, making it suitable for molding. An object of the present invention is to provide an aluminum material for a cap that does not cause peeling of ink or paint film and also improves workability during film formation.

Means for Solving the Problems In achieving the above object, the present invention is characterized in that a dried film of a polyolefin resin dispersion aqueous solution is employed as a base film for painting, etc. On the other hand, one of the inventions is one in which a dried film (2) of a polyolefin resin dispersion aqueous solution is directly coated on the surface of an aluminum base material (1), as shown in FIG. First, as shown in FIG. 2, the film (2) is replaced with a metal-containing resin film (3).
) is formed by coating the aluminum base material (1) via the aluminum base material (1).

The composition of the aluminum base material (1) is not particularly limited as long as it has moldability and other properties required for containers, caps, etc.

The dry film (2) of the polyolefin resin dispersion aqueous solution as the base film is formed by applying a treatment liquid in which the polyolefin resin is the main component of the dispersion resin and dispersing it in an aqueous solution, and then through a drying process. It is something. Examples of the polyolefin resin include modified thermoplastic elastomers, modified low-density polyethylenes, modified ionomers, modified ethylene-vinyl acetate copolymer resins, and modified polyethylene waxes. These may be dispersed singly in an aqueous solution, or two or more of them may be mixed and dispersed in an arbitrary ratio. Particularly preferably, when forming a coating directly on the surface of the aluminum base material (1), a treatment liquid containing modified low density polyethylene resin or modified ionomer resin as the main component of the dispersed resin is preferably used; When forming a coating via 3), it is preferable to use a treatment liquid containing a modified ionomer resin or a modified ethylene-vinyl acetate copolymer resin as a main component of the dispersed resin. Further, as a method for applying the treatment liquid, any method such as a spray method, a dipping method, a roll coating method, a brush coating method, etc. can be adopted. Further, it is desirable that drying after application be carried out at a temperature of about 15 to 300°C. The drying time may vary depending on the drying temperature; for example, at 100 to 150°C, it is recommended to dry for about 30 seconds.

By the way, in this invention, the amount of the dry film (2) of the polyolefin resin dispersion aqueous solution is the same as that of the aluminum base material (1).
0.17I1g/ff when coated directly on the surface of
1 or more, or 0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000. 5 my / 7 ft or more" (2). Film amount is 0.1#Ig
This is because if it is less than /m or less than 0.5 mg/TIi, corrosion resistance, adhesion to coating films and printing inks, etc. will be poor. Conversely, in both cases, the amount of film is 3000111g.
/TIl or less is desirable. 3000m'i/r
Even if a coating is formed in an amount exceeding d, corrosion resistance is no longer achieved.
This is because it does not contribute to the two effects of ``adhesiveness with printing ink, etc.'', but rather leads to disadvantages such as increased costs due to wasted materials. The preferred film amount is 1 to 1 in all cases.
300m1/rtt.

The metal-containing resin film (3) is interposed between the dry film (2) of the polyolefin resin dispersion aqueous solution and the aluminum base material (1) for the purpose of further improving adhesion between the two and improving corrosion resistance. It is something. Preferred examples of this metal-containing resin film (3) include a mixed film containing a chromium compound and a water-soluble resin, or a mixed film of a zirconium compound, a monoolefin or olefin polymer, and a polymer having a hydroxyl group or a carboxyl group. sell. To explain each, first, the chromium-containing resin film is
It is formed through a process of applying and drying a treatment liquid in which a chromium compound and a water-soluble resin are mixed in an aqueous solution or emulsion state. Here, as a chromium compound, 3
Examples include various salts and oxides (eg, Cr203) containing valent or hexavalent chromium. On the other hand, the resin is a water-soluble polymer having a hydroxyl group or a carboxyl group, such as polyacrylic acid, polyvinyl alcohol, ethylene maleic anhydride, polyvinyl methyl ether, etc. Among them, polyacrylic acid is preferred. The mixing ratio of the chromium compound and the resin should be set to a value such that the content ratio of chromium and water-soluble resin in the mixed film is about 1:chromium to 0.5 to 10 resin. It is good to set the value to about 1 to 5, preferably about 1 to 5.

On the other hand, a zirconium-containing mixed film is formed by coating and drying a treatment liquid in which a zirconium compound, a monoolefin or olefin polymer, and a polymer having hydroxyl or carboxyl groups are mixed in an aqueous solution or emulsion state. It is. Here, the zirconium compounds include, for example, alkali metal salts of ammonium zirconium carbonate and fluorozirconate;
Examples include ammonium salts.

In addition, monoolefins or olefin polymers include ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2- Methyl-2
Butene, 1-hexene, 2,3-dimethyl-2-butene, 1-heptene, 1-octene, 1-nonene, 1-1
10 - Decene etc. can be mentioned. Among them, it is preferable to use ethylene and propylene. Examples of polymers having hydroxyl or carboxyl groups include polyacrylic acid, polyvinyl alcohol, cellulose hydroxyethyl ether, ethylene maleic anhydride, polyvinylpyrrolidine, and polyvinylmethyl ether. Examples include acrylic copolymer latex. Among these, polyacrylic acid is preferred. Here, to explain the mixing ratio of the above three components, the monoolefin or olefin polymer is 10 to 95 parts, more preferably 6 parts.
The amount is preferably 0 to 90 parts. The addition of a monoolefin or olefin polymer is particularly useful for improving the moldability of the film itself, but if it exceeds 95 parts, it will no longer be a water-soluble resin. For polymers having hydroxyl or carboxyl groups, the amount is preferably 5 to 50 parts, more preferably 10 to 40 parts.

The ratio of the zirconium compound is such that the ratio of zirconium and the total of both types is 1 zirconium to 0.5 of the repolymer.
The amount is preferably 10 parts, more preferably 1 to 5 parts.

The method for applying the treatment liquid for forming a metal-containing resin film as described above onto the surface of the aluminum base material (1) includes a spray method,
Any method such as a dipping method or a roll coating method can be used. Further, it is desirable that drying after coating be carried out at a temperature of about 15 to 300°C.

The drying time varies depending on the drying temperature, and for example, at 150°C, it is recommended to dry for about 30 seconds. Also, the amount of chromium or zirconium deposited on the film is 0.11 mg/rr? ”−
It is desirable that the material be formed in a state specified by the following. 0.1m
If it is less than g/r+f, the adhesion to the dry film (2) of the polyolefin resin dispersion aqueous solution coated on the surface of the surface becomes poor. Further, it is desirable that the amount of adhesion be 500 mg/ni' or less. Even if the amount exceeds 500 mg/rrP, it will not be possible to significantly increase the effect of improving adhesion to the dry film (2), and the material will be wasted.

The desired adhesion range is 0. 5-50 mg/rr
It is r+. The amount of chromium or zirconylam deposited may be set by adjusting the mixing ratio of the chromium compound or zirconium compound and the water-soluble resin at the manufacturing stage of the treatment solution, or by adjusting the amount of the treatment solution applied to the aluminum substrate. You can go. In this case, the coating amount, that is, the coating amount of the metal-containing resin film is 0°5 to 300.
It is desirable to set it to about 0 mg/rrf' from the point of view of film thickness, etc., and suitably it is good to set it to about 3 to 300 mg/rrf'.

As shown in Figure 3, containers and cages are generally produced by printing or resin coating the aluminum material mentioned above to form a printed layer (4) and a coating layer (5). After that, baking is performed by performing other processes, etc., and then molding it into a predetermined shape. Vinyl and epoxy resins are generally used as coating resins. A size coat is no longer necessary for this printing or resin coating.

As described in detail, the present invention provides a method in which a dried film of an aqueous polyolefin resin dispersion solution is formed on the surface of an aluminum base material directly or via a metal-containing resin film as a base film for painting or printing. Therefore, as is clear from consideration of the examples described later, the size code
Even if step 1 is omitted and the surface of the film is directly printed or coated with resin, it can maintain excellent adhesion with resin and printing ink, and also be stable against heat. Therefore, the coating film will not be damaged during molding into containers or caps or during retort sterilization. Moreover, the coating has excellent corrosion resistance, and can prevent the coating from being corroded by the contents of the container and further corrode the aluminum base material during long-term storage, thereby improving the corrosion resistance of the container and the cap.

Furthermore, it has excellent slip properties.
Another advantage is that the film formation process is easy due to the non-rinsing process, and there is no need for waste liquid treatment of treatment liquid or washing water.

Example Next, examples of the present invention will be shown in comparison with comparative examples.

[Example 1] A treatment liquid (solid content concentration 3 wt%) consisting of an aqueous dispersion solution of an ionomer resin was prepared using JIS 1200 and having a thickness of 0.2
It was applied onto the surface of a 5 mm aluminum base material using a rubber roll, and then dried at 150° C. for 30 seconds to obtain an aluminum material according to the present invention having a dry film of an aqueous polyolefin resin dispersion solution on the surface. The amount of film at this time was 100,711 g/m.

[Example 2] Using the same aluminum base material as in Example 1, a treatment liquid having a composition as shown in Table 1 below at 10% (V/V) dilution was applied to the surface of the base material using a rubber roll. Dilute with
Next, it was dried at 150° C. for 30 seconds to form a chromium-containing resin film. The amount of chromium deposited at this time is approximately 2m'
It was j/lri.

Table 1 Next, a treatment solution (
Solid content concentration 3wt%) was applied to the surface of the chromium-containing resin film using the same rubber roll, and then heated at 150°C x 30°C.
Drying was performed for seconds to obtain an aluminum material according to the present invention having a dried film of an aqueous polyolefin resin dispersion on its surface. The coating amount at this time was 1100rn/d.

[Example 3] A stock solution was prepared by mixing a mixture of 13% Zr02 and 87% water with a 13% aqueous solution of a material consisting of 80 parts of ethylene and 20 parts of polyacrylic acid.
(%) A diluted solution was prepared as a treatment solution. The treatment solution was applied using a rubber roll to the surface of the same aluminum base material as in -16= Example 1, and then dried at 150°C for 30 seconds to first form a zirconium-containing resin film. The amount of zirconium deposited at this time was approximately 30 mg/77/.

Next, a treatment solution (
Solid content concentration 3 wt%) was applied to the surface of the zirconium-containing resin film using the same rubber roll, and then heated at 150°C.
Drying was performed for x30 seconds to obtain an aluminum material according to the present invention having a dried film of a polyolefin resin dispersion aqueous solution on the surface. The amount of film at this time is 100mg/TIt
Met.

[Comparative Example 1] Using the same aluminum base material as in 1, a conventional aluminum material was obtained by coating the surface of the aluminum base material with a phosphoric acid-chromate film by a well-known method. The amount of chromium deposited was about 10 my/rd.

[Comparative Example 2] An aluminum material (without film treatment) consisting of a rolled aluminum base material having the same composition and shape as above was obtained.

The following tests were conducted on the five types of aluminum materials obtained above.

[Adhesiveness test of resin coating film and printing ink] 2. Approximately 10% of black acrylic resin was applied to the surface of each aluminum material.
It was coated to a thickness of μm and dried at 200° C. for 10 minutes to form a coating film. Similarly, the surface of each aluminum material was printed using ink made of black alkyd resin, and then dried at 150° C. for 10 minutes to form a printed layer with a thickness of about 1 μm. The resin-coated test materials were directly stretched using an Erichsen tester based on JIS B7729 (primary adhesion test), and after the coating film was formed,
After being immersed in hot water at 5°C for 30 minutes, Erichsen overhang processing (secondary adhesion test) was carried out in the same manner, and the printed sample materials were only subjected to the first adhesion test. The peeling state of the coating film and printing ink was visually observed. The results are shown in Table 2 as O: No peeling was observed, Δ: Fine peeling was observed, and ×: Severe peeling.

[Slip property test] The five types of aluminum materials mentioned above were molded under the same conditions, and the slip properties were evaluated using a J slip tester. Table 2 shows those with poor performance.

[Corrosion resistance test] JISZ23 for each of the above five types of aluminum materials.
The corrosion state of the surface was investigated when salt water spray according to No. 71 was applied for 150 hours. The results are shown in Table 2 as ○: No corrosion observed, Δ: Slight corrosion observed, and X: Severe corrosion. Furthermore, each aluminum material was examined for surface discoloration when immersed in hot water at 95° C. or higher for 30 minutes.

The results are shown in Table 2 as ○: No discoloration was observed, Δ: Slight discoloration was observed, and ×: Severe discoloration.

It is clear from the above results in Table 2 that the aluminum material according to the present invention has superior adhesion to paint films and printing inks, as well as smoothness and It can be seen that it also has excellent corrosion resistance.

[Brief explanation of the drawing]

Figure 1 is an enlarged cross-sectional view of an aluminum material according to the present invention in which a dry film of an aqueous polyolefin resin dispersion solution is directly coated on an aluminum base material, and Figure 2 is a dry film of an aqueous polyolefin resin dispersion solution coated on an aluminum base material through a metal-containing resin film. FIG. 3 is an enlarged sectional view of the aluminum material of the present invention having a film formed thereon. FIG. 3 is an enlarged sectional view of the aluminum material of FIG. 1 with a coating layer or a printed layer formed thereon. (1)...Aluminum base material, (2)...Dry film of polyolefin resin dispersion aqueous solution, (3)...Metal-containing resin film, (4)...Printed layer, (5)... Paint layer. Figure 3 above

Claims (8)

[Claims] (1) A dried film of a polyolefin resin dispersion aqueous solution is applied to the surface of an aluminum base material as a base film for painting, etc.
．． An aluminum material for molding having a base film for painting, etc., characterized in that the coating is formed in an amount of 1 mg/m^2 or more. (2) The aluminum material for molding having a base film for painting, etc., according to claim 1, wherein the polyolefin resin is a modified low-density polyethylene resin. (3) The aluminum material for molding having a base film for painting, etc., according to claim 1, wherein the polyolefin resin is a modified ionomer resin. (4) A metal-containing resin film is formed on the surface of the aluminum base material, and on the surface of the metal-containing resin film,
An aluminum material for molding having a base film for painting, etc., characterized in that the base film for painting, etc. is formed by coating a dried film of a polyolefin resin dispersion aqueous solution in an amount of 0.5 mg/m^2 or more. . (5) The aluminum material for molding having a base film for painting, etc., according to claim 4, wherein the metal-containing resin film is a mixed film containing a chromium compound and a water-soluble resin. (6) The metal-containing resin film has a base film for painting, etc. as set forth in claim 4, which is a mixed film of a zirconium compound, a monoolefin or an olefin polymer, and a polymer having a hydroxyl group or a carboxyl group. Aluminum material for molding. (7) An aluminum material for molding having a base film for painting, etc. according to any one of claims 4 to 6, wherein the polyolefin resin is a modified ionomer resin. (8) An aluminum material for molding having a base film for painting, etc. according to any one of claims 4 to 6, wherein the polyolefin resin is a modified ethylene-vinyl acetate copolymer resin.