Method and apparatus for cleaning seamless aluminum cans

Abstract

To provide a method for cleaning a seamless aluminum can, simplified as compared with conventional cleaning methods without spoiling the quality of a cleaned seamless aluminum can, and a device for cleaning the seamless aluminum can.SOLUTION: A method for cleaning a seamless aluminum can molded by draw-ironing molding using a coolant comprises at least: the degreasing step of degreasing the seamless aluminum can using a degreasing agent; the washing step of washing the degreased seamless aluminum can; and the surface treatment step of surface-treating the seamless aluminum can by a surface treatment bath including a film formation agent and a surface control agent.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for cleaning seamless aluminum cans. [Background technology]

[0002] Conventionally, aluminum seamless cans have been widely used as containers for food and beverages such as beer and carbonated drinks. Such aluminum seamless cans are obtained by subjecting aluminum sheets to severe processing such as drawing and ironing, and are generally formed using a lubricant (coolant). As a result, the lubricant and aluminum powder (smut) adhere to the seamless can after drawing and ironing. In addition, a coating such as aluminum oxide is formed on the surface of the aluminum sheet. Cans on which such lubricants and other substances have adhered and on which an aluminum oxide coating has formed must have the adhering lubricants and other substances removed before they are subjected to the subsequent painting and printing processes. In addition, the cans are subjected to a degreasing process using a degreaser containing a surfactant and an etching agent, and a water washing process in order to form a good chemical conversion coating on the aluminum surface.

[0003] After degreasing and water-rinsing, seamless aluminum cans are subjected to acid washing to form an oxide layer mainly composed of aluminum oxide or hydroxide, which makes the aluminum surface chemically inactive and prevents the occurrence of an appearance defect known as brown spots (Patent Document 1). Furthermore, the seamless cans that have been acid-washed are subjected to a water-washing process and a drying process, and are then transferred to a painting / printing process, etc., but it is necessary to impart slipperiness to the can surface to improve the transportability of the seamless cans, and to impart hydrophilicity so that the water film that has adhered to the can surface in the water-washing process can be effectively removed before the drying process. For this reason, a surface conditioner that reduces the static friction coefficient of the can surface is sprayed onto the seamless cans that have been washed in the water-washing process, and then the cans are subjected to a drying process (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5007482 [Patent Document 2] Patent No. 3186189 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned method for cleaning aluminum seamless cans requires many steps, such as a degreasing step, a water-rinsing step, a film-forming treatment step for forming a film mainly composed of an oxide or hydroxide of aluminum, a water-rinsing step, a surface treatment step, a water-rinsing step, and a drying step, and therefore the line for cleaning aluminum seamless cans is very long and the equipment is inevitably large. On the other hand, each step is essential for providing good aluminum seamless cans, and it is difficult to omit them.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a cleaning method and apparatus for cleaning seamless aluminum cans which is simpler than conventional cleaning methods without impairing the quality of the cleaned seamless aluminum cans. [Means for solving the problem]

[0007] According to the present invention, a method for cleaning aluminum seamless cans formed by drawing and ironing using a coolant includes a pre-cleaning step for pre-cleaning the aluminum seamless cans, a degreasing step for degreasing the aluminum seamless cans using a degreaser, a water-rinsing step for rinsing the degreased aluminum seamless cans with water, and a surface treatment step for surface-treating the aluminum seamless cans that have been subjected to the water-rinsing step in a surface treatment bath containing a film-forming treatment agent and a surface conditioner, the film-forming treatment agent being a water-soluble phosphoric acid or phosphate salt having a phosphoric acid concentration of 1 to 50 ppm in the surface treatment bath. The present invention provides a method for cleaning aluminum seamless cans, the method comprising the steps of: (a) providing a surface conditioner containing a main component (A) which is a polyoxyethylene alkyl ether having an EO addition mole number of 3 to 8, an HLB value of 8 to 12, and a carbon chain number of 10 to 14, and (b) which disperses the main component (A) and the polyoxyethylene alkyl ether having an EO addition mole number of 6 to 10, an HLB value of 12 to 14, and a carbon chain number of 8 to 12, the ratio of A to B being 1:0.2 to 1:1; and (b) providing a surface conditioner used in a surface treatment bath at a concentration of 50 to 1000 ppm.

[0008] The cleaning method of the present invention preferably includes a drying step of drying the aluminum seamless can that has been subjected to the surface treatment step, after the surface treatment step.

[0009] According to the present invention, a cleaning device for cleaning aluminum seamless cans formed using a coolant includes a pre-cleaning means for pre-cleaning the aluminum seamless cans supplied from a forming means, a degreasing means for degreasing the aluminum seamless cans supplied from the pre-cleaning means with a degreaser, a water washing means for washing the aluminum seamless cans supplied from the degreasing means with water, a surface treatment means for surface treating the aluminum seamless cans supplied from the water washing means with a surface treatment bath containing a film-forming treatment agent and a surface conditioner, and a drying means for drying the aluminum seamless cans supplied from the surface treatment means, and a transport means for continuously transporting the aluminum seamless cans from the forming means to the drying means. the film-forming treatment agent is an aqueous solution of phosphoric acid or a phosphate salt having a phosphoric acid concentration of 1 to 50 ppm in the surface treatment bath, the surface conditioner contains a main component (A) which is a polyoxyethylene alkyl ether having an EO addition mole number of 3 to 8, an HLB value of 8 to 12, and a carbon chain number of 10 to 14, and a dispersant (B) which disperses the main component (A) and is a polyoxyethylene alkyl ether having an EO addition mole number of 6 to 10, an HLB value of 12 to 14, and a carbon chain number of 8 to 12, the ratio of A to B being 1:0.2 to 1:1, and the surface conditioner is used in a concentration of 50 to 1000 ppm in the surface treatment bath.The present invention provides an apparatus for cleaning aluminum seamless cans. Effect of the Invention

[0010] In the method for cleaning aluminum seamless cans of the present invention, the film formation process of forming an inactive treatment film on the aluminum surface, which has conventionally been carried out after the degreasing and water rinsing processes, is carried out simultaneously with the surface treatment process using a surface conditioner. This makes it possible to shorten the line for cleaning aluminum seamless cans and reduce the size of the equipment. Moreover, even with this simplified process, the lubricant that has adhered to the aluminum seamless can during the drawing and ironing process can be efficiently cleaned. Furthermore, by simultaneously carrying out acid washing in a surface treatment step using a surface conditioner, the occurrence of brown spots caused by the reaction of water with aluminum can also be effectively prevented. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a flow chart showing a general flow of a conventional aluminum can washing process. [Diagram 2] FIG. 1 is a flow chart showing a preferred flow of the aluminum can washing process of the present invention. [Diagram 3] FIG. 1 is a side view diagrammatically illustrating an example of a cleaning device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Cleaning method) As described above, a method for cleaning aluminum seamless cans (hereinafter sometimes referred to as "aluminum cans") requires many steps, such as a degreasing step, a water-rinsing step, an acid treatment step, a water-rinsing step, a surface treatment step, and a drying step. If a water-rinsing step is performed before and after each step, as shown in FIG. 1, in addition to the above essential steps, a preliminary cleaning step is performed before the degreasing step, a first water-rinsing step is performed between the degreasing step and the film-forming treatment step, a second water-rinsing step and a rinsing step with pure water are performed between the film-forming treatment step and the surface treatment step using a surface conditioner, and a drying step is performed after the surface treatment step. This causes a problem that the number of steps is large and the cleaning line becomes long. In the cleaning method of the present invention, as shown in FIG. 2, a film formation treatment step in which an inactive treatment film is formed on the aluminum surface is carried out simultaneously with a surface treatment step, making it possible to omit the film formation treatment step and the water rinsing step following the film formation treatment step, and thus shortening the cleaning line. Furthermore, in the surface treatment step, a film for inactivating the aluminum surface can be formed simultaneously with the surface treatment with the surface conditioner, so that the occurrence of brown spots can also be effectively suppressed.

[0013] [Seamless aluminum cans] In the cleaning method of the present invention, the aluminum can to be cleaned is an aluminum seamless can formed using a lubricant as a coolant during forming. Specifically, it is a seamless can formed by rigorous processing such as drawing, drawing / deep drawing, drawing / ironing, drawing / bending / stretching / ironing, using a conventionally known lubricant such as mineral oil or synthetic oil, from an aluminum plate made of known aluminum or aluminum alloy such as 3004 material or 3104 material. Furthermore, seamless cans formed by such a forming method are not only contaminated by the lubricant, but also by smut and the like generated during the processing. Furthermore, as described above, an aluminum oxide coating is formed on the surface of the aluminum plate.

[0014] [Degreasing process / cleaning process] Aluminum cans with lubricating oil on them are continuously conveyed at high speed to the degreasing process of the washing equipment with the bottoms facing up. Before the degreasing process, a preliminary washing process is provided as necessary to remove smut and other impurities. In the degreasing step, a conventionally known degreaser made of an alkali or acid can be used. Specifically, a degreaser containing a surfactant and an etching agent is used and sprayed onto the aluminum can from above and below. The physical impact of the surfactant removes the lubricant adhering to the surface of the aluminum can, and the etching agent dissolves the aluminum, removing the aluminum oxide film that has formed on the surface of the aluminum can. The aluminum cans subjected to the degreasing step are washed with water in a washing step, and then transported to a surface treatment step. In the preferred embodiment shown in Fig. 2, the washing step is performed in two steps, a first water washing step and a pure water rinsing step, but the washing step is not limited to this and can be changed as appropriate.

[0015] [Surface treatment process] In the surface treatment process, a surface treatment bath containing a film-forming treatment agent and a surface conditioner is applied to the surface of the aluminum can. By applying the surface conditioner to the surface of the aluminum can, the outer surface of the aluminum can is given hydrophilicity and the lubricity of the aluminum can is improved. In other words, when a surfactant is used as a surface conditioner, the hydrophilic group of the surfactant is adsorbed to the aluminum base material surface, and the hydrophilic group and hydrophobic group are arranged on the surface layer side, giving the aluminum can hydrophilicity. As a result, it is possible to remove and reduce the moisture that adheres to the can by washing with water after the surface treatment before the drying process, and the drying temperature in the drying process can be reduced. In addition, after drying, the lubricity of the hydrophobic group improves the lubricity, improving the transportability of the aluminum can. Furthermore, in the present invention, by carrying out surface treatment in this surface treatment step using a surface treatment bath containing a film-forming treatment agent together with a surface conditioner, it becomes possible to effectively suppress the occurrence of brown spots on aluminum cans, which was previously suppressed by the film-forming treatment step for inactivating the aluminum surface that was conventionally carried out after the degreasing step. That is, when aluminum reacts with the pure water used in the washing process, an oxide film called a boehmite film grows significantly, causing brown spots. When these brown spots occur, printing unevenness occurs in the subsequent printing and painting processes, resulting in poor appearance characteristics. However, in the present invention, by treating the surface of aluminum cans with a film-forming treatment agent in the surface treatment process, a film mainly composed of oxide or hydroxide of aluminum is formed, which makes it possible to chemically inactivate the aluminum surface, and it becomes possible to effectively prevent the occurrence of brown spots without the need for a separate acid treatment process.

[0016] In the present invention, as the surface conditioner, it is preferable to use a surfactant as described above, and in particular, a nonionic surfactant such as polyoxyethylene alkyl ether can be suitably used. By using the main component (A), which is a polyoxyethylene alkyl ether having 3-8 EO addition moles, 8-12 HLB value, and 10-14 carbon chain number, and the polyoxyethylene alkyl ether dispersant (B), which disperses the main component (A) and has 6-10 EO addition moles, 12-14 HLB value, and 8-12 carbon chain number, as a dispersant, the stock solution to be replenished to the surface treatment bath is stabilized, and stable production of quality is possible. The ratio of A to B is 1:0.2 to 1:1, and if it is 1:1 or more, foaming occurs and treatment becomes impossible, and if it is 1:0.2 or less, the stock solution stability decreases. The film-forming treatment agent to be contained in the surface treatment bath together with the surface conditioner preferably contains an inorganic acid such as sulfuric acid, nitric acid or phosphoric acid or an inorganic acid salt thereof, and is particularly preferably an aqueous solution containing phosphoric acid or a phosphate salt.

[0017] The surface treatment bath used in the surface treatment step contains the above-mentioned surface conditioner and film-forming treatment agent, and it is preferable that the surface treatment bath contains the above-mentioned surfactant as a surface conditioner in an amount of 50 to 1000 ppm, particularly 100 to 400 ppm. If the amount of the surfactant is less than the above range, there is a risk that sufficient slipperiness cannot be imparted to the aluminum can, whereas if the amount of the surfactant is more than the above range, there is a risk that the appearance characteristics of the outer surface of the can after drying will be impaired. On the other hand, when phosphoric acid or an aqueous solution containing phosphoric acid is used, the film-forming treatment agent is preferably contained so that the phosphoric acid concentration in the surface treatment bath is 1 to 50 ppm, particularly 5 to 10 ppm. If the phosphoric acid concentration is lower than the above range, there is a risk that the generation of an oxide film on the surface of an aluminum can cannot be sufficiently suppressed, while if the phosphoric acid concentration is higher than the above range, further improvement in the effect of suppressing the generation of brown spots cannot be expected, and the cost efficiency will be poor.

[0018] The surface treatment bath can be applied to the surface of an aluminum can by a conventional method such as a dipping method or a spraying method, as long as the surface treatment bath can be brought into contact with the inner and outer surfaces of the aluminum can. From the viewpoint of productivity, however, the spraying method is preferable. The surface treatment bath is preferably brought into contact with the aluminum can for 3 to 10 seconds, depending on the concentration of phosphoric acid. If the contact time is shorter than the above range, it may not be possible to form a good coating mainly composed of an oxide or hydroxide of aluminum. On the other hand, if the contact time is longer than the above range, the coating formed will not change and the productivity may decrease. In addition, the surface treatment bath is preferably adjusted to a temperature of 20 to 40° C., which allows efficient formation of a good coating capable of suppressing the occurrence of brown spots. The aluminum cans that have been surface-treated in the surface treatment bath are transported to a drying process.

[0019] [Drying process] The surface-treated aluminum cans that have been transported to the drying process are heated and dried in a dryer such as an oven. As described above, aluminum cans that have been through the surface treatment process have excellent hydrophilicity and therefore reduced adhering moisture, and by drying at a temperature of 160 to 210°C for 70 to 240 seconds, aluminum cans that are free of brown spots and have excellent lubricity are produced. Since the dried aluminum cans have excellent slipperiness, even when the aluminum cans are placed next to each other with no gaps between them, they do not clog the conveying path and can be smoothly conveyed to the printing process. In addition, since the inner surface of the aluminum cans also has high slipperiness, the mandrels for holding the aluminum cans can be smoothly inserted, significantly improving productivity.

[0020] (Cleaning Equipment) The washing apparatus for washing aluminum cans of the present invention comprises a pre-washing means for pre-washing aluminum cans having a lubricant or the like attached thereto and supplied from a forming apparatus, a degreasing means for degreasing the aluminum cans supplied from the pre-washing means with a degreaser, a water-washing means for rinsing the aluminum cans supplied from the degreasing means, a surface treatment means for surface-treating the aluminum cans supplied from the water-washing means with a surface treatment bath containing a film-forming treatment agent and a surface conditioner, and a drying means for drying the aluminum cans supplied from the surface treatment means, as well as a conveying means for continuously conveying the aluminum cans from the forming apparatus to the drying means. That is, in the cleaning device of the present invention, the film forming means and the water washing means following the film forming means, which are conventionally provided after the degreasing means, are omitted, so that the cleaning device can be made compact and energy-efficient. Also, the number of steps is reduced, so the workload for maintenance and cleaning of the device is reduced.

[0021] 3 is a side view that shows a schematic diagram of one example of the cleaning apparatus of the present invention, in which aluminum cans 1 having lubricants or the like attached thereto are carried in from a molding apparatus (not shown) and are continuously transported by a transport means 2 to a drying means 8. As the transport means, a conventionally known transport means such as a mesh conveyor or a belt conveyor can be used, and a plurality of aluminum cans are placed in a line in the width direction of the transport means (perpendicular to the traveling direction) with their openings facing downward, and are continuously transported. As is clear from FIG. 3, in a preferred embodiment of the cleaning apparatus of the present invention, a preliminary cleaning means 3, a degreasing means 4, cleaning means (a first water washing means 5 and a pure water rinsing means 6), a surface treatment means 7 and a drying means 8 are installed along the conveying means 2 from the upstream (the left side of FIG. 3) to the downstream (the right side of FIG. 3) of the cleaning apparatus. Each of the means, the preliminary cleaning means 3, the degreasing means 4, the cleaning means 5, 6, and the surface treatment means 7, is provided with spray devices 10, 10, 10... having multiple outlets capable of spraying degreaser, cleaning water, pure water, and surface treatment bath from above and below the aluminum can in each process, and blower devices 11, 11, 11... for blowing away the degreaser, cleaning water, etc., that have accumulated at the bottom of the aluminum can. The installation of the blower device 11 makes it possible to prevent cleaning water, etc., from accumulating even if the can bottom is a dome-shaped bottom that is concave inward. In addition, following the surface treatment means 7, a vacuum transfer device 9 is installed which adsorbs the bottoms of the aluminum cans and transports them in a bridging manner in order to remove aluminum cans that are not in an inverted position with their bottoms facing upward.

[0022] The aluminum cans 1 carried out from the forming device are first sprayed with cleaning water from a spray device 10 in the preliminary cleaning means 3 by the conveying means 2, and then the cleaning water accumulated at the bottom of the can is blown away by a blower device 11, thereby removing in advance any dirt other than the lubricant that adhered during forming. The cans are then carried into the degreasing means 4, where a degreaser containing a surfactant and an etching agent is sprayed from above and below the aluminum can 1 by the spray device 10, and the degreaser that has accumulated at the bottom of the can is removed by the blower device 11, thereby removing the lubricant and smut that have adhered to the aluminum can, and also removing the aluminum oxide film that has formed on the surface by etching the aluminum surface. The aluminum cans 1 transported from the degreasing means 4 are washed by spraying and blowing off cleaning water using the spray device 10 and blower device 11 of the first water washing means 5, and then the pure water rinsing means 6 sprays pure water using the spray device 10 and removes the pure water accumulated at the bottom of the can using the blower device 11, and the cans are transported to the surface treatment means 7.

[0023] In the surface treatment means 7, a surface treatment liquid containing a surface conditioner and a film-forming treatment agent is sprayed from above and below the aluminum cans by a spray device 10, thereby treating the surface of the aluminum cans. After the excess surface treatment liquid that has accumulated at the bottom of the cans is blown away by a blower device 11, only the aluminum cans in an inverted state with their bottoms facing up are carried into the drying means 8 by a vacuum transfer device 9. As described above, since the surfaces of the surface-treated aluminum cans have excellent hydrophilicity, the washing water from the washing means 5 and 6 is easily removed by the air blown by the blower device 11, and therefore the drying time in the drying means 8, which is then carried in, can be shortened. The drying means 8 can be a conventional heating and drying device such as an oven. As described above, the aluminum cans dried by the drying means 8 have their surfaces coated with a surface conditioner to improve slipperiness, so that the aluminum cans do not stick to each other and cause clogging of the transport path when transported to the printing process, and can be transported smoothly to the printing process. In addition, the occurrence of brown spots is suppressed by the film-forming treatment agent, so the cans are also excellent in printability.

[0024] The cleaning device of the present invention is not limited to the specific example shown in Fig. 3, and the required number or length (line length) of cleaning devices may be installed before and after the degreasing device and the surface treatment device, and the number of nozzles of the spray device and the number of blower devices may also be changed appropriately. Furthermore, the installation position of the vacuum transfer device 9 may also be changed appropriately as long as the aluminum cans conveyed out of the cleaning device of the present invention do not clog the conveying path. EXAMPLES

[0025] The following examples of the method for cleaning seamless aluminum cans are given below, but the present invention is not limited to these examples. <Examples 1 to 6 and Comparative Examples 1 to 8> The surface treatment baths according to the examples and comparative examples were prepared at the concentrations shown in Table 1. For the preparation, an aqueous solution containing 5% by mass of polyoxyethylene alkyl ether (A), an aqueous solution containing 5% by mass of polyoxyethylene alkyl ether (B), and an aqueous solution containing 2% by mass of sodium dihydrogen phosphate in terms of phosphate ions were used, and the surface treatment baths were prepared by diluting with water to the concentrations shown in Table 1. An aluminum seamless can was used as the object to be treated, and after a preliminary water washing step, the can was spray washed with water for 10 seconds, and after a degreasing step, the can was spray degreased for 60 seconds using a degreaser Surf Cleaner NHC310 manufactured by Nippon Paint Surf Chemicals Co., Ltd., and then sprayed with water for 10 seconds as a water washing step. After a pure water rinsing step by spraying for 10 seconds, the can was sprayed with the above-prepared surface treatment bath for 10 seconds as a surface treatment step, and then dried at 170°C for 3 minutes as a drying step. After drying, the aluminum seamless cans were evaluated for brown spots, appearance, and lubricity under the following conditions, and the stock solutions for preparing the surface treatment baths and the stability and foaming properties of the stock solutions of the surface treatment baths were evaluated under the following conditions.

[0026] [Brown spot evaluation] For each of the aluminum seamless cans of the Examples and Comparative Examples, the presence or absence of brown spots (parts discolored to brownish red) in the center of the inner surface was visually evaluated according to the following criteria. The results are shown in Table 1. ○: No occurrence ×: Occurred

[0027] [Appearance evaluation] The aluminum seamless cans of each Example and Comparative Example were visually inspected for the presence or absence of whitening in the center of the outer can bottom according to the following criteria. The results are shown in Table 1. ○: No whitening ×: Whitening

[0028] [Stability evaluation of undiluted solution] An aqueous solution containing 5% by mass of polyoxyethylene alkyl ether (A) and (B) in total in the ratio (A:B) shown in Table 1 was prepared, and after standing for 24 hours, the presence or absence of separation was visually evaluated. The results are shown in Table 1. ○: No separation ×: Separation occurs

[0029] [Slipperiness evaluation] Two seamless aluminum cans from each Example and Comparative Example were placed horizontally in contact with each other in the same direction, and one can was placed on top of the other in the opposite direction like a bale. The cans were then tilted at a speed of 50° / 30 seconds, at which point the can began to slide. The results are shown in Table 1. ○: Less than 50° ×: 50° or more

[0030] [Foaming evaluation] 30 L of the surface treatment bath was prepared, and the foaming height was evaluated when the prepared surface treatment bath was sprayed and stirred for 3 minutes. The results are shown in Table 1. ○: Less than 5cm ×: 5cm or more

[0031] [Table 1] [Explanation of symbols]

[0032] Reference Signs List 1 aluminum can, 2 conveying means, 3 pre-cleaning means, 4 degreasing means, 5, 6 cleaning means, 7 surface treatment means, 8 drying means, 9 vacuum transfer device.

Claims

1. A method for cleaning aluminum seamless cans formed by drawing and ironing using a coolant, comprising the steps of: the aluminum seamless can is subjected to a pre-cleaning step, a degreasing step, a water-washing step, a surface treatment ... a surface conditioner that is used in a surface treatment bath at a concentration of 50 to 1000 ppm; and a surface conditioner that is used in a surface treatment bath at a concentration of 50 to 1000 ppm. The method for cleaning aluminum seamless cans is characterized in that the film-forming treatment agent is an aqueous solution of phosphoric acid or a phosphate salt having a phosphoric acid concentration of 1 to 50 ppm in the surface treatment bath; the surface conditioner contains a main component (A) that is a polyoxyethylene alkyl ether having an EO addition mole number of 3 to 8, an HLB value of 8 to 12, and a carbon chain number of 10 to 14, and a dispersant (B) that disperses the main component (A) and the polyoxyethylene alkyl ether having an EO addition mole number of 6 to 10, an HLB value of 12 to 14, and a carbon chain number of 8 to 12, the ratio of A to B being 1:0.2 to 1:

1.

2. 2. The cleaning method according to claim 1, further comprising a drying step of drying the aluminum seamless can that has been subjected to the surface treatment step, after the surface treatment step.

3. A cleaning device for cleaning aluminum seamless cans formed using a coolant, comprising: the aluminum seamless can supplying means for supplying the aluminum seamless cans from the forming means to the drying means; a pre-cleaning means for pre-cleaning the aluminum seamless cans supplied from the pre-cleaning means, a degreasing means for degreasing the aluminum seamless cans supplied from the pre-cleaning means with a degreaser; a water-washing means for rinsing the aluminum seamless cans supplied from the degreasing means with water; a surface treatment means for surface-treating the aluminum seamless cans supplied from the water-washing means with a surface treatment bath containing a film-forming treatment agent and a surface conditioner; and a drying means for drying the aluminum seamless cans supplied from the surface treatment means; and a conveying means for continuously conveying the aluminum seamless cans from the forming means to the drying means, The cleaning device for aluminum seamless cans is characterized in that the film-forming treatment agent is an aqueous solution of phosphoric acid or a phosphate having a phosphoric acid concentration of 1 to 50 ppm in the surface treatment bath, the surface conditioner contains a main component (A) which is a polyoxyethylene alkyl ether having an EO addition mole number of 3 to 8, an HLB value of 8 to 12, and a carbon chain number of 10 to 14, and a dispersant (B) which disperses the main component (A) and the polyoxyethylene alkyl ether having an EO addition mole number of 6 to 10, an HLB value of 12 to 14, and a carbon chain number of 8 to 12, the ratio of A to B being 1:0.2 to 1:1, and the surface conditioner is used in a surface treatment bath at a concentration of 50 to 1,000 ppm.

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