Manufacturing method of metal container

Abstract

To provide a method for manufacturing a metal container that includes: an ink application step of applying radiation-curable ink to the surface of the metal container, which has openings, side walls, and a bottom; a curing step of irradiating the radiation-curable ink with radiation to cure the same to form a radiation-cured resin layer; and a heating step of heating the radiation-cured resin layer to over 100°C.SOLUTION: The heating step is carried out using one or more of high-frequency induction heating, hot air heating, far infrared heating, or flame treatment.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a metal container. [Background technology]

[0002] Patent Document 1 describes a stackable metal cup having a hollow shape that is open at the top, a body portion having an inner diameter or outer diameter that tapers downward so that the inner diameter at the upper end is larger than the outer diameter at the lower end, and a bottom portion having a grounding portion connected to the lower end of the body portion via a curvature portion, wherein in a stacked state, a region P where the angle of the body portion with respect to the horizontal plane is in the range of 85 to 90 degrees and a region Q where the angle is in a range smaller than region P are alternately continuous in the height direction so that a gap t of 0.5 mm or more is formed between the inner diameter of the body portion of the lower metal cup and the outer diameter of the body portion of the upper metal cup.'' [Prior art document] [Patent documents] [Patent Document 1] JP 2023-46747 A Summary of the Invention

[0003] In a first aspect of the present invention, there is provided a method for manufacturing a metal container, comprising an ink application step, a curing step, and a heating step. In the ink application step, a radiation curable ink is applied to the surface of a metal container having an opening, a sidewall, and a bottom. In the curing step, radiation is irradiated to cure the radiation curable ink to form a radiation cured resin layer. In the heating step, the radiation cured resin layer is heated to 100°C or higher.

[0004] In the above, the heating step may be carried out by one or more of high-frequency induction heating, hot air heating, far-infrared heating, and flame treatment.

[0005] In the above, the radiation cured resin layer may be heated to 150° C. or more and 250° C. or less in the heating step.

[0006] In the above, in the heating step, the radiation-cured resin layer may be maintained at 100° C. or higher for 1 second or more.

[0007] In the above, the ink application step may include printing using a radiation curable ink by one or more of printing with a printing plate and inkjet printing.

[0008] In the above, the ink application step may include performing offset printing using radiation curable ink.

[0009] The above method may further include a molding step of molding a metal container. The molding step may mold the metal container from a sheet material having a metal sheet and a resin film layer covering at least one side of the metal sheet, or from a sheet material having a metal sheet. The ink application step may include applying a radiation curable ink to the resin film layer.

[0010] In the above, a flame treatment may be included after the molding step and before the ink application step, in which a flame is brought into contact with the resin film layer to modify the surface of the resin film layer.

[0011] In the above, the average thickness of the side wall of the metal container may be 0.08 to 0.22 mm.

[0012] The above summary of the invention does not list all of the features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0013] [Figure 1] An example of a metal container 100 according to this embodiment is shown. [Diagram 2] An example of a layer structure 200 of the metal container 100 of this embodiment is shown. [Diagram 3] An example of a layer structure 200 of the metal container 100 of this embodiment is shown. [Figure 4] An example of a flow of a method for manufacturing the metal container 100 of this embodiment will be described. [Diagram 5] An example of a sub-flow of S200 is shown. [Figure 6] An example of a sub-flow of S400 is shown. [Figure 7] An example of a flow of a method for manufacturing the metal container 100 of this embodiment will be described. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0015] 1 shows an example of a metal container 100 according to the present embodiment. The metal container 100 is a metal container capable of holding contents. The metal container 100 may be used for the purpose of holding beverages and / or food.

[0016] The metal container 100 comprises a container body having an opening 110, a sidewall 120, and a bottom 130.

[0017] 1, the opening 110 may be a ring-shaped portion of the container body in which an opening is formed. The sidewall portion 120 forms a sidewall of the container body and may be cylindrical in shape. The bottom portion 130 may be the bottom of the container body and hold the contents from below.

[0018] In the metal container 100, the container body may have a cup-like shape that is used with the opening 110 open. The container body may have a shape in which the inner diameter is largest at the opening 110 and decreases toward the bottom 130. This makes it possible to stack the metal containers 100, and therefore allows a plurality of metal containers 100 to be stacked for storage and transportation.

[0019] As shown in FIG. 1, the container body may have a curled portion 140 around the periphery of the opening 110, which curves the end of the container body toward the outside in the radial direction of the container. The side wall portion 120 may have a shape that gradually reduces in diameter from the opening 110 to the bottom portion 130, either uniformly or in a stepped shape. In addition, the side wall portion 120 may have a shape that combines curved and straight lines in its cross-sectional shape. For example, the side wall portion 120 may have a shape that includes a bulging portion 150 that bulges outward. By having the bulging portion 150 in the container body, the metal containers 100 can be easily pulled apart when they are separated from each other in a stacked state. The bottom portion 130 of the container body may have a dome-like shape that protrudes toward the opening 110 side.

[0020] The metal container 100 may be a cylindrical can container with a lid attached to the opening 110. The can container may be cylindrical with a shape on the upper part of the side wall portion 120 that tapers from the bottom portion 130 to the opening 110. The can container may be bottle-shaped with the opening 110 provided at a narrow mouth portion.

[0021] In the metal container 100, the container body may be made of aluminum or an aluminum alloy. The container body may be made of stainless steel or steel. The container body may be made of a metal sheet. For example, the average thickness of the side wall portion 120 of the metal container 100 may be 0.08 to 0.22 mm. Within this range, it is possible to achieve both appropriate flexibility and strength. Furthermore, it is possible to combine the convenience of a paper cup with the luxurious feel of a metal cup.

[0022] 2 shows an example of a layer structure 200 of the metal container 100 of this embodiment. The metal container 100 includes a radiation cured resin layer 230 formed on at least a part of the surface of a container body 210.

[0023] The container body 210 may be the same as described above.

[0024] The radiation cured resin layer 230 provides aesthetics to the metal container 100. The radiation cured resin layer 230 may be formed on the outer surface 214 of the container body 210, as shown in Figure 2. The radiation cured resin layer 230 may be formed on the inner surface 212 of the container body 210.

[0025] The radiation cured resin layer 230 may be provided in any region of the metal container 100 shown in Fig. 1. For example, the radiation cured resin layer 230 may be formed on the side wall portion 120 and / or the bottom portion 130 of the container body 210.

[0026] The radiation cured resin layer 230 includes a radiation curable ink. The radiation curable ink is an ink that is cured by radiation such as ultraviolet light or an electron beam, and may be, for example, an ultraviolet curable ink or an electron beam curable ink. The ultraviolet curable ink may include, for example, an ultraviolet curable acrylic resin, an epoxy resin, a polyester resin, or a polyurethane resin. The radiation cured resin layer 230 is formed by applying the radiation curable ink to at least a part of the surface of the container body 210 and then curing it by irradiating it with radiation.

[0027] The radiation cured resin layer 230 may form an image. The image may include a pattern such as a design, a picture, a character, a symbol, a color, etc. The radiation cured resin layer 230 may be formed as a print layer including an image.

[0028] In the metal container 100 of this embodiment, the radiation cured resin layer 230 is subjected to a heat treatment after being cured by irradiation. The details of the heat treatment will be described later. By performing a heat treatment after curing, the water resistance of the radiation cured resin layer 230 can be improved.

[0029] The radiation cured resin layer 230 may be formed as a single layer or as multiple layers. When formed as a multiple layer, the radiation cured resin layer 230 may further include a protective layer containing a transparent resin formed on a layer containing an image. The radiation cured resin layer 230 may also be formed to include a base coat layer, such as a white solid print layer or an anchor coat layer, and a layer containing an image.

[0030] In the metal container 100 of this embodiment, as described above, by providing the radiation cured resin layer 230 that has been subjected to a heat treatment after curing, it is possible to improve the water resistance of the radiation cured resin layer 230 formed on the surface of the metal container 100. This makes it possible to provide a metal container 100 having a printed layer with excellent water resistance.

[0031] 3 shows an example of a layer structure 200 of the metal container 100 of this embodiment. The metal container 100 comprises a resin film layer 220 covering at least one side of a container body 210, and a radiation cured resin layer 230 formed on at least a part of the surface of the resin film layer 220. The above description of the container body may be applied to the container body 210 as is.

[0032] The resin film layer 220 covers at least a part of the surface of the container body 210, and has the role of improving the slipperiness of the metal container 100 when the metal container 100 is subjected to diameter reduction drawing. The resin film layer 220 may be a film made of a thermoplastic resin. The resin film layer 220 may contain a polyester resin and / or a polyolefin resin. The polyester resin may be, for example, polyethylene terephthalate. The resin film layer 220 may be a coating made of a thermosetting resin and / or a thermoplastic resin. Examples of paints capable of forming a coating include polyester-based, acrylic-based, urethane-based, silicone-based, and fluorine-based paints.

[0033] The resin film layer 220 may be formed on the inner surface 212 and / or the outer surface 214 of the container body 210 .

[0034] At least a part of the surface of the resin film layer 220 may be subjected to a surface modification treatment. The details of the surface modification treatment will be described later.

[0035] In the example of layer configuration 200 shown in Fig. 3, the surface free energy of the surface of the resin film layer 220 when the resin film layer 220 has been subjected to a surface modification treatment may be 44 mN / m or more and less than 60 mN / m. When the surface free energy of the surface of the resin film layer 220 is 44 mN / m or more, the adhesion between the resin film layer 220 and the radiation cured resin layer 230 is improved. When the surface free energy of the surface of the resin film layer 220 is less than 60 mN / m, the penetration of water into between the resin film layer 220 and the radiation cured resin layer 230 is suppressed. This further improves the water resistance of the radiation cured resin layer 230 formed on the surface of the resin film layer 220, and also improves the scratch resistance and peel resistance of the radiation cured resin layer 230.

[0036] A radiation cured resin layer 230 is formed on at least a portion of the surface of the resin film layer 220. The radiation cured resin layer 230 imparts an aesthetic appearance to the metal container 100. The radiation cured resin layer 230 may be formed on the surface of the resin film layer 220 formed on the outer surface 214 of the container body 210 as shown in Fig. 3. The radiation cured resin layer 230 may also be formed on the surface of the resin film layer 220 formed on the inner surface 212 of the container body 210. The radiation cured resin layer 230 may be formed on the side wall portion 120 and / or the bottom portion 130 of the container body 210 in the metal container 100 shown in Fig. 1.

[0037] The radiation cured resin layer 230 may be formed by applying radiation curable ink and then curing it by irradiating it with radiation. The above description may be applied to the radiation curable ink as is. The radiation cured resin layer 230 may be formed by curing the radiation curable ink and then subjecting it to a heat treatment. By subjecting the radiation cured resin layer 230 to a heat treatment after curing, the water resistance of the radiation cured resin layer 230 can be improved.

[0038] In the metal container 100 of this embodiment, the radiation cured resin layer 230 that has been subjected to a heat treatment after curing is provided, thereby improving the water resistance of the radiation cured resin layer 230 formed on the surface of the metal container 100. This makes it possible to provide a metal container 100 having a printed layer with excellent water resistance.

[0039] Next, a method for manufacturing the metal container 100 of this embodiment will be described. Fig. 4 shows an example of a flow of the method for manufacturing the metal container 100 of this embodiment. The method for manufacturing the metal container 100 of this embodiment can be performed by a molding step S200, a radiation cured resin layer forming step S400, and a heating step S500 shown in Fig. 4. For convenience of explanation, the above-mentioned processes will be explained in order, but at least some of these processes may be performed in parallel, each step may be interchanged without departing from the spirit of the present invention, and some steps may be omitted without departing from the spirit of the present invention.

[0040] First, in S200, a forming step is performed in which a metal container 100 having an opening 110, a side wall 120, and a bottom 130 is formed from a sheet material having a metal sheet. The forming of the metal container 100 may be performed by forming a container body by a known forming method according to the shape of the metal container 100. The above description of the container body may be applied as it is.

[0041] Fig. 5 shows an example of a subflow of S200. When the container body has a cup-like shape in which the inner diameter of the opening 110 is the largest and the diameter decreases toward the bottom 130 as shown in Fig. 1, a cup-like container body may be formed by executing S210 to S250 in Fig. 5.

[0042] First, in S210, a sheet material having a metal sheet is punched and subjected to drawing and / or ironing to form a cup-shaped bottomed cup. Here, the metal sheet may be formed by cutting a metal sheet wound in a coil shape. The metal sheet may be made of aluminum or an aluminum alloy. Alternatively, the metal sheet may be made of stainless steel or steel. The thickness of the metal sheet may vary depending on the application of the metal container 100. In S210, the sheet material may be drawn and / or ironed multiple times depending on the shape of the container body to form a bottomed cup.

[0043] Next, in S220, the tip of the bottomed cup formed in S210 is trimmed. In S220, the uneven tip height of the bottomed cup caused by drawing and / or ironing is evenly cut around the central axis to make the tip height of the bottomed cup after trimming constant.

[0044] Next, in S230, a tip diameter-reducing draw is performed on the tip of the trimmed bottomed cup. In S230, as a diameter-reducing draw process for the tip, the tip opening of the bottomed cup is gradually reduced in diameter toward the tip.

[0045] Next, in S240, curling or flange forming is performed on the tip opening of the bottomed cup to form the opening 110.

[0046] Next, in S250, a gradual diameter-reducing draw is performed on the bottom 130 side from the location where the tip diameter-reducing draw was performed in S230 to form the side wall portion 120 having an overall tapered contour.

[0047] With the sub-flow shown in FIG. 5, a container body having a cup-like shape as shown in FIG. 1 is formed.

[0048] Next, in S400, a radiation-curing resin layer forming step of forming a radiation-curing resin layer 230 on the surface of the metal container 100 formed in S200 is performed. The description of the radiation-curing resin layer 230 may be directly applied as described above.

[0049] FIG. 6 shows the sub-flow of S400. The above-described radiation-curing resin layer forming step may be executed from S410 to S420 shown in FIG. 6.

[0050] First, in S410, an ink application step of applying a radiation-curing ink to the surface of the metal container 100 is executed.

[0051] In S410, the radiation-curing ink may be applied to the surface of the metal container 100 by printing. Alternatively, the radiation-curing ink may be applied by a roller or a spray.

[0052] In S410, the ink application step may include printing using a radiation curable ink by one or more of printing with a printing plate and inkjet printing. The plate printing may be offset printing, screen printing, flexographic printing, or gravure printing using a gravure roller. From the viewpoint of further enhancing the effect of improving water resistance by the heating step described below, it is preferable to perform printing by offset printing in the ink application step.

[0053] In the ink application step S410, an image may be formed on the surface of the metal container 100 by printing with a printing plate using radiation curable ink or by inkjet printing. The image may include a pattern such as a design, a picture, a letter, a symbol, or a color.

[0054] Next, in S420, a curing step is performed in which the radiation curable ink applied in S410 is cured to form the radiation cured resin layer 230. In S420, the radiation curable ink may be cured by irradiating with radiation. If the radiation curable ink includes ultraviolet ray curable ink, the ultraviolet ray curable ink is cured by irradiating with ultraviolet ray in S420. As a result, the radiation cured resin layer 230 is formed.

[0055] In S410 and S420, the radiation cured resin layer 230 may be formed in a single layer or in multiple layers. When the radiation cured resin layer 230 is formed in multiple layers, for example, a printed layer containing an image may first be applied and cured to form the layer, and a protective layer containing a transparent resin may be further formed thereon. Alternatively, a base coat layer such as a solid white printed layer or an anchor coat layer may be formed, and a printed layer containing an image may be further formed thereon to form the radiation cured resin layer 230. When the radiation cured resin layer 230 is formed in multiple layers, the radiation cured resin layer 230 may be formed by applying and curing a first radiation cured resin layer, followed by subjecting the surface of the first radiation cured resin layer to a surface modification treatment such as a frame treatment, and then forming a second radiation cured resin layer on the first radiation cured resin layer.

[0056] Next, in S500, a heating step is performed to heat the radiation cured resin layer 230 formed in S400.

[0057] In S500, the heating step may be performed by one or more of high-frequency induction heating, hot air heating, far-infrared heating, and flame treatment. When the heating step is performed by high-frequency induction heating, the manufacturing line can be designed to be compact, and the space required for production equipment can be saved. For example, the heating step may be performed by arranging a high-frequency induction heating coil in the manufacturing line for the metal container 100 and inductively heating the metal container 100 with the coil.

[0058] In the heating step, the radiation cured resin layer 230 may be heated to 100° C. or higher. Heating the radiation cured resin layer 230 to 100° C. or higher can improve the water resistance of the radiation cured resin layer 230. For example, in the heating step, the radiation cured resin layer 230 may be heated to 150° C. or higher and 250° C. or lower.

[0059] In the heating step, heat treatment is performed so that the heating temperature of the radiation cured resin layer 230 is maintained for a predetermined time. For example, heat treatment may be performed so that the radiation cured resin layer 230 is maintained at 100°C or higher for 1 second or more. Specifically, the radiation cured resin layer 230 may be heated to maintain 100°C for 20 seconds or more, 150°C for 5 seconds or more, or 200°C for 1 second or more. When the heating temperature is high, the water resistance of the radiation cured resin layer 230 can be improved and the efficiency of the manufacturing process can be improved even if the time for maintaining the heating temperature is shortened.

[0060] A metal container 100 having the layer structure 200 shown in Fig. 2 may be manufactured by the flow of the manufacturing method for the metal container 100 shown in Fig. 4. By the flow of the manufacturing method for the metal container 100 shown in Fig. 4, the water resistance of the radiation cured resin layer 230 formed on the surface of the metal container 100 can be improved, and thus a metal container 100 having a printed layer with excellent water resistance can be provided.

[0061] Fig. 7 shows an example of a flow of a method for manufacturing a metal container 100 of this embodiment. The method for manufacturing a metal container 100 of this embodiment can be performed by a resin film layer forming step S100, a molding step S200, a surface modification treatment step S300, a radiation cured resin layer forming step S400, and a heating step S500 shown in Fig. 7. For convenience of explanation, the above-mentioned processes are explained in order, but at least some of these processes may be performed in parallel, each step may be interchanged within the scope of the present invention, and some steps may be omitted within the scope of the present invention.

[0062] First, in S100, a resin film layer 220 is formed on at least one surface of a metal sheet that forms the container body of the metal container 100. In S100, a sheet material is formed that has a metal sheet and the resin film layer 220 that covers at least one surface of the metal sheet.

[0063] The metal sheet may be formed by cutting a coiled metal sheet. The above description may be applied to the metal sheet as it is. In S100, the resin film layer 220 may be formed on the surface of the metal sheet that will become the inner surface 212 and / or the outer surface 214 of the container body after the manufacturing of the metal container 100.

[0064] The resin film layer 220 may be formed on the metal sheet by extrusion coating, cast film heat bonding, biaxially stretched film heat bonding, etc. The resin film layer 220 may be formed to have a thickness in the range of 2 to 30 μm.

[0065] Next, in S200, a molding process is performed in which the metal container 100 is formed from a sheet material having a metal sheet and a resin film layer 220 covering at least one side of the metal sheet. The molding process may be described by replacing "a sheet material having a metal sheet" with "a sheet material having a metal sheet and a resin film layer 220 covering at least one side of the metal sheet" in the description of the flow in Fig. 4.

[0066] Next, in S300, a surface modification process is performed to modify at least a part of the surface of the resin film layer 220 of the container body formed in S200. In the flow shown in Fig. 7, the surface modification process may be performed before the ink application process in S400.

[0067] The surface modification treatment may include a flame treatment in which a flame is brought into contact with at least a part of the surface of the resin film layer 220 to modify the surface. The surface modification treatment may include a corona treatment or an atmospheric pressure plasma treatment.

[0068] In S300, the surface free energy of the surface of the resin film layer 220 after the surface modification treatment may be 44 mN / m or more and 60 mN / m or less. When the surface free energy of the surface of the resin film layer 220 is 44 mN / m or more, the adhesion between the resin film layer 220 and the radiation cured resin layer 230 is improved. When the surface free energy of the surface of the resin film layer 220 is less than 60 mN / m, the penetration of water between the resin film layer 220 and the radiation cured resin layer 230 is suppressed. This further improves the water resistance of the radiation cured resin layer 230 formed on the surface of the resin film layer 220, and also improves the scratch resistance and peel resistance of the radiation cured resin layer 230.

[0069] In the flow of the manufacturing method shown in FIG. 7, the above-mentioned surface modification treatment step S300 may be omitted.

[0070] Next, in S400, a radiation cured resin layer forming step is performed to form a radiation cured resin layer 230 on at least a portion of the surface of the resin film layer 220. The explanation of the radiation cured resin layer forming step may be the same as that in the flow of FIG.

[0071] Next, in S500, a heating step is performed to heat the radiation cured resin layer 230 formed in S400. The heating step may be explained in the same manner as in the flow chart of FIG.

[0072] A metal container 100 having the layer structure 200 shown in Fig. 3 may be manufactured by the flow of the manufacturing method for the metal container 100 shown in Fig. 7. The flow of the manufacturing method for the metal container 100 shown in Fig. 7 can improve the water resistance of the radiation cured resin layer 230 formed on the metal container 100, thereby providing a metal container 100 having a printed layer with excellent water resistance. In addition, by forming a resin film layer 220 that has been subjected to a surface modification treatment on the surface of the container body 210 and then forming a radiation cured resin layer 230 on the surface of the resin film layer 220, the water resistance of the radiation cured resin layer 230 can be further improved and the scratch resistance and peel resistance of the radiation cured resin layer 230 can be improved.

[0073] Table 1 shows the results of a test on the water resistance of the radiation cured resin layer 230 in the metal container 100 manufactured according to the flow shown in Fig. 7. The water resistance test was performed by immersing the metal container 100 in water at 25°C for a predetermined period of time, and then attaching cellophane tape to the surface of the radiation cured resin layer 230 and peeling it off to evaluate the peelability of the radiation cured resin layer 230. [Table 1]

[0074] In Table 1, "heating conditions" indicate the heating temperature and the time for which the heating temperature was maintained for the radiation cured resin layer 230. "Immersion time" indicates the length of time that the metal container 100 was immersed in water at 25° C. In Table 1, the peelability was expressed by the following index. ◯: No peeling. ×: Peeling occurred.

[0075] As shown in Table 1, by subjecting the cured radiation-cured resin layer 230 to a heat treatment, the water resistance of the radiation-cured resin layer 230 after immersion in water was improved. Furthermore, although water resistance improves depending on the time the heating temperature is maintained, by performing heat treatment at a high temperature, excellent water resistance was obtained even when the heating time was shortened.

[0076] Table 2 shows the results of testing the water resistance of the radiation cured resin layer 230 when the heating step was carried out by high-frequency induction heating in the flow shown in Fig. 7. The water resistance test and evaluation were carried out in the same manner as the example shown in Table 1. [Table 2]

[0077] As shown in Table 2, by subjecting the cured radiation-cured resin layer 230 to a short-time heat treatment using high-frequency induction heating, the water resistance of the radiation-cured resin layer 230 after immersion in water was improved.

[0078] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0079] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0080] 100 metal containers 110 Opening 120 Side wall 130 Bottom 140 Curl section 150 Bulge 200 layer configuration 210 Container body 212 Inner surface 214 Outer surface 220 Resin film layer 230 Radiation curing resin layer

Claims

1. an ink application step of applying a radiation curable ink to a surface of a metal container having an opening, a side wall, and a bottom; a curing step of irradiating radiation to cure the radiation curable ink to form a radiation cured resin layer; a heating step of heating the radiation cured resin layer to 100° C. or higher; A method for manufacturing a metal container comprising the steps of:

2. The heating step is carried out by one or more of high-frequency induction heating, hot air heating, far-infrared heating, and flame treatment. The method for manufacturing a metal container according to claim 1 .

3. In the heating step, the radiation cured resin layer is heated to 150° C. or higher and 250° C. or lower. A method for manufacturing a metal container according to claim 1.

4. In the heating step, the radiation cured resin layer is maintained at 100° C. or higher for 1 second or more. A method for manufacturing a metal container according to claim 1.

5. the ink application step includes performing printing using the radiation curable ink by one or more of printing with a printing plate and inkjet printing; A method for manufacturing a metal container according to claim 1.

6. the ink application step includes performing offset printing using the radiation curable ink; A method for manufacturing a metal container according to claim 1.

7. The method further includes a molding step of molding the metal container from a sheet material having a metal sheet and a resin film layer covering at least one side of the metal sheet, or a sheet material having a metal sheet, the ink applying step includes applying a radiation curable ink to the resin film layer; A method for manufacturing a metal container according to claim 1.

8. a flame treatment for modifying a surface of the resin film layer by contacting the resin film layer with a flame after the molding step and before the ink application step; The method for manufacturing a metal container according to claim 7.

9. The average thickness of the side wall of the metal container is 0.08 to 0.22 mm. The method for manufacturing a metal container according to claim 1 .

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