JPH1015632A - Production of aerosol can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a complete paint film of internal face by forming the paint film of internal face by executing, at least, spray painting of more than two times in the internal face painting process for an aerosol can. SOLUTION: After the internal face of a can body 1 is cleaned, the internal face of the can body 1 is treated with spray painting of the first time. This spray painting is executed by using an injection nozzle downward gun to spray on the total internal face of the can body 1 and an injection nozzle upward gun to spray on parts of a shoulder part 6 and a recessing part concentrically. After then, the can is exposed inside the atmosphere of about 150 deg.C in about 90 seconds, an excess paint is scattered, further, spray painting of second time is executed, and at last it is finished via baking of about 295 deg.C in about 16 minutes. Therefore, the aerosol can with the excellent corrosion resistance against the content can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an aerosol can, and more particularly, to an improvement in a method for coating an inner surface of an aerosol can.

[0002]

2. Description of the Related Art Conventionally, when manufacturing aerosol cans, various types of inner surface coating have been applied to the inner surface of the can. This prevents the metal such as Al forming the inner wall of the can body from being corroded by the contents stored in the can body, or the metal being eluted by the contents and being mixed into the contents. That's why. Particularly, in a can body containing contents containing a corrosive component, a paint is spray-coated on the inner surface of the can body to form an inner coating film. As the inner surface paint of the can body, paints such as epoxyphenol-based resin, epoxyamino-based resin, and vinyl-based resin are often used in terms of adhesion and corrosion resistance.

[0003] As a method of manufacturing such a conventional aerosol can, for example, there is the following manufacturing method. First, as shown in FIG. 1, Al slag is subjected to impact molding to produce a bottomed can 1. Next, neck-in processing is performed on the opening 3 of the can body 1, bead processing is performed on the outer periphery of the opening 3, and various processing (cutting, curling, etc.) is performed on the tip of the opening 3 as necessary. Alternatively, the can body 1 is cleaned by solvent cleaning, and then the inner surface is coated. For the inner surface coating, a spray gun downward is inserted from the opening 3 of the can 1 and spray coating is performed on the entire inner surface of the can 1. Next, after baking, as shown in FIG. 3, the holding pin 9 is inserted into the can 1 to hold the can 1,
After a base coating (ground printing) is applied to the outer surface, drying is performed, and finally, desired printing is performed.

[0004]

However, in the conventional method for manufacturing an aerosol can, as shown in FIG. 1, the diameter of the opening 3 of the can body 1 is narrowed so that the diameter is small and the can height is small. Since it is high, there is a disadvantage that the inner surface coating film 5 is not uniformly fixed on the inner surface of the can 1 by only one spray coating performed before the printing process. In particular, since the spray direction of the conventionally used spray gun is downward, the opening 3
In many cases, the inner coating 5 at the shoulder 6 or the concave portion 4 becomes incomplete, and it was impossible to provide a practical can 1 with completely assured corrosion resistance. Conventionally, after the inner surface coating, the holding pins 9 are inserted into the can body 1 to hold the can body 1 and are conveyed to the printing process. Therefore, the inner coating of the rotating can body 1 is performed at the time of base coating. There is a disadvantage that rubbing occurs between the membrane 5 and the holding pin 9 which does not rotate. Further, since the inner coating film 5 is softened by drying after the base coating and printing is performed in the softened state, there is a problem that the inner coating film 5 in the rotating can body 1 is significantly damaged by the holding pins 9. . The electric current value of the inner surface coating film 5 destroyed by the damage is high (the lower the electric current value, the less damage to the coating film due to processing), and there is a disadvantage that it is not practically suitable.

[0005] The present invention is an invention which has solved the above-mentioned drawbacks. In the method of manufacturing an aerosol can, the inner surface of the can is protected by protecting the inner wall of the can by completely coating the inner surface of the can. It is an object of the present invention to provide a method for producing an aerosol can having excellent corrosion resistance to articles.

[0006]

According to the present invention, a can body 1 is formed by an impact molding method, and an opening 3 of the can body 1 is subjected to neck-in processing. The outer periphery of the part 3 is subjected to bead processing and various processing (cutting, curling, and the like) to the tip of the opening 3 as required, and then, after each step of cleaning and inner surface coating, finally, printing is performed on the outer surface of the can body 1. In the method for manufacturing an aerosol can comprising a printing step, in the inner coating step, the inner coating film is formed by spray coating at least twice or more, and as an example, the diameter of the can body is as follows. 1
The present invention is characterized in that it is applied to a small aerosol can of 0 to 35 mm.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 7 are drawings showing an embodiment of the present invention. In the figure, the description of the manufacturing method of the present invention which is the same as the conventional manufacturing method of the aerosol can is omitted. The feature of the manufacturing method of the aerosol can according to the present invention, which is different from the conventional manufacturing method, is that after the cleaning step of the can body 1,
The point is that the inner surface coating is performed at least twice. The following are two examples (first embodiment and second embodiment).

In the first embodiment, after the inner surface of the can 1 was cleaned, the inner surface of the can 1 was spray-painted for the first time. The spray coating was performed using a spray gun downward spraying the entire inner surface of the can body 1 and a spray gun upward spray gun for spray-coating the portions of the shoulder 6 and the concave portion 4 intensively. After that, it is exposed to an atmosphere of 150 ° C. for about 90 seconds to scatter excess paint (hereinafter referred to as “pre-heating”), further spray-coated, and finally baked at 295 ° C. for 16 minutes. Finished. In the first embodiment,
The inner coating film 5 has a thickness of 5 μm to 30 μm. FIG. 2 is an enlarged cross-sectional view (enlarged view of a portion A in FIG. 1) of the inner coating film 5 of the first embodiment, where 7 is the inner coating film formed by the first spray coating, and 8 is 2 This is the inner coating film formed by the second spray coating. After the inner coating is performed twice, as shown in FIG. 3, a holding pin 9 is inserted into the can body 1, and the can body 1 is held by the holding pin 9 and printed by a transport device moved by a chain 11. It is transported to the process. In the embodiment shown in FIG.
The cut cylindrical body 10 is inserted. Cylinder 10
Is formed to be larger than the outer diameter of the holding pin 9, so that it can freely rotate around the holding pin 9. Further, since the cylindrical body 10 is divided and inserted into a short length, even if the inner coating film 5 and the holding pin 9 are partially rubbed, the can 1
The cylindrical body 10 that comes into contact with the rotation of the cylinder 10 rotates freely. Therefore, direct rubbing between the inner coating film 5 and the holding pin 9 can be prevented. The most frequent damage due to rubbing occurs in the can body 1 during base coating.
And rotation of the can 1 during printing performed after the base coating. In particular, since the can 1 is dried after the base coating, the inner coating 5
Is softened, and the inner coating film 5 is significantly rubbed during subsequent printing. As a material of the cylindrical body 10, a fluororesin, a silicone resin, or the like is used.

In the second embodiment, after the inner surface of the can 1 is cleaned, the inner surface of the can 1 is subjected to a first spray coating (the spray coating method is the same as that of the first embodiment), and thereafter. Preheating was performed. After this process was repeated four times, baking was performed. (After the fourth spray coating, baking was performed immediately without performing preheating.) The subsequent printing process is the same as in the first embodiment.
In the second embodiment, the inner coating film 5 has a thickness of 15 μ to 35 μ. The inner paint used for the spray coating is an epoxyphenol-based resin, an epoxyamino-based resin, a vinyl-based resin, or the like in both the first and second embodiments.
As described above, in the examples shown in the first embodiment and the second embodiment, the current value of the inner coating film 5 is 20 mA on average (6.3 V DC).
The results are as follows, and a remarkable effect was obtained as compared with the case where the average of the energization value in the case of the conventional spray coating only once was 100 mA (DC 6.3 V).

The operation of the present invention having the above configuration will be described. In the method of manufacturing an aerosol can according to the present invention, before the can 1 enters the printing process,
Since the inner surface coating 5 is formed by spraying (first embodiment) to four times (second embodiment), the inner surface coating becomes perfect.

[0011]

FIG. 4 to FIG. 7 show a specific embodiment of the present invention.
Shown in 4 to 7 are sectional views showing an embodiment of an aerosol can assembled by fixing a valve 2 and the like to a can 1 produced by the above-described manufacturing method of the present invention. FIG. 4 shows a state in which the valve 2 is inserted into the mouth 3 of the can 1 and is covered with a cover 12 so as to cover the valve 2 from above, and the tip 12 a of the cover 12 is hooked on the recess 4 of the can 1. This is an embodiment in which the valve 2 is fixed in the mouth 3 of the can 1 by caulking. In addition, packing 13 is inserted in the gap between the can 1 and the valve 2 to prevent the contents in the can 1 from leaking.

FIG. 5 shows that a valve 2 is inserted into a mouth 3 of a can 1 similarly manufactured by the manufacturing method of the present invention, and a tip 3a of the mouth 3 is bent on the top surface of the valve 2. This is an embodiment in which the valve 2 is fixed in the mouth 3 of the can 1 by caulking. Similarly, a packing 13 is inserted into a gap between the can 1 and the valve 2.

FIGS. 6 and 7 show aerosol cans of the type shown in FIGS. 4 and 5, respectively. Similarly, an inner cylinder 14 is suspended in a can 1 made by the manufacturing method of the present invention. FIG. 4 is a cross-sectional view showing a double aerosol container that has been applied. In addition, similarly, packing 13 is inserted between the can 1 and the inner cylinder 14 and between the valve 2 and the inner cylinder 14.

In the present invention, the diameter of the can is 10 mm.
It goes without saying that the present invention can be applied to an aerosol can having a normal size of 35 mm or more, in addition to a small aerosol can having a size of from 35 mm to 35 mm.

[0015]

As described above, perfect internal coating of an aerosol can was conventionally impossible, but according to the manufacturing method of the present invention, a perfect internal coating film can be formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an aerosol can manufactured by the method for manufacturing an aerosol can according to the present invention.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is a sectional view showing a holding pin for holding the aerosol can according to the present invention.

FIG. 4 is a cross-sectional view of an aerosol can when a valve is fixed to a can body manufactured by the manufacturing method according to the present invention via a cover.

FIG. 5 is a cross-sectional view of an aerosol can in a case where a valve is fixed to the can manufactured by the manufacturing method according to the present invention, by bending a tip of a mouth of the can.

FIG. 6 is a cross-sectional view of a double aerosol container when an inner cylinder is suspended in a can body manufactured by the manufacturing method according to the present invention.

FIG. 7 is a cross-sectional view of a double aerosol container when an inner cylinder is suspended in a can body manufactured by the manufacturing method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Can body 3 Opening 5 7 8 Inner coating film

Claims (2)

[Claims] 1. A can body is formed by an impact molding method, neck-in processing is performed on an opening of the can body, and then bead processing is performed on the outer periphery of the opening and various processing (cutting / curling) is performed on a tip of the opening. Etc.) as necessary, followed by washing and inner coating processes, and finally a printing process of printing on the outer surface of the can body. In the aerosol can manufacturing method, at least two times in the inner coating process. A method for producing an aerosol can, characterized in that an inner coating film is formed by the above spray coating. 2. The diameter of the can body is 10 mm to 35 m.
2. A small aerosol can of m.
A method for producing the aerosol can as described above.