Metal container and manufacturing method of metal container

Abstract

To provide a metal container that includes a container body, a base color resin layer, and a different color resin layer, as well as a method for manufacturing the metal container.SOLUTION: The metal container includes: a container body having an opening, a side wall, and a bottom; a base color resin layer formed on at least a part of the surface of the container body and containing a base color resin; and a different color resin layer that includes a resin of a color other than the base color, formed in a predetermined pattern shape in a pseudo base color area provided on at least a part of the surface of the base color resin layer. The color difference ΔE* in the L*a*b* color space between the base color resin layer and the pseudo base color area is 2.5 or less. The manufacturing method includes a base color resin layer forming step and a different color resin layer forming step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a metal container and 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, a metal container is provided. The metal container includes a container body, a base color resin layer, and an other color resin layer. The container body may have an opening, a side wall, and a bottom. The base color resin layer may include a base color resin formed on at least a part of the surface of the container body. The other color resin layer may include a resin of a color other than the base color formed in a predetermined pattern shape in a pseudo base color region provided on at least a part of the surface of the base color resin layer. The color difference ΔE* in the L*a*b* color system between the base color resin layer and the pseudo base color region may be 2.5 or less.

[0004] In the above, the base color resin layer may be white.

[0005] In the above, the difference in L* value in the L*a*b* color system between the base color resin layer and the pseudo base color region may be 2.5 or less.

[0006] In the above, the pseudo base color region may be formed on the entire surface of the base color resin layer.

[0007] In the above, the pattern shape may include one or more shapes of a dot pattern, a line pattern, a random pattern, a barcode, and a two-dimensional code.

[0008] In the above, the pattern shape includes a shape in which the same or similar repeating units are repeated, and the length of the repeating unit may be 0.01 to 1 mm.

[0009] In the above, the pattern shape may be provided at an area density of 3 to 15% of the pseudo base color region.

[0010] In the above, the base color resin layer may be a cured radiation cured resin.

[0011] In the above, a pattern printed layer on which a pattern is printed may be further provided on the container body, the base color resin layer, or the other color resin layer.

[0012] The above may further comprise a peelable release film provided so as to be in direct contact with the other color resin layer.

[0013] In the above, the container body may include a metal layer and a resin film layer covering one or both sides of the metal layer.

[0014] In the above, the average thickness of the side wall of the metal container may be 0.08 to 0.22 mm.

[0015] In a second aspect of the present invention, there is provided a method for manufacturing a metal container. The method for manufacturing a metal container includes a base color resin layer forming step and an other color resin layer forming step. In the base color resin layer forming step, a base color resin layer containing a base color resin may be formed on at least a part of the surface of a container body having an opening, a side wall, and a bottom. In the other color resin layer forming step, an other color resin layer containing a resin of a color other than the base color formed in a predetermined pattern shape may be formed on a pseudo base color region provided on at least a part of the surface of the base color resin layer. The color difference ΔE* in the L*a*b* color system between the base color resin layer and the pseudo base color region may be 2.5 or less.

[0016] In the above, the base color resin layer forming step and / or the other color resin layer forming step may be performed by inkjet printing.

[0017] In the above, the method may further include a molding step of forming a 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, and the ink application step may include applying a radiation-curable ink to the resin film layer.

[0018] In the above, a surface modification treatment for modifying the surface of the resin film layer may be included after the molding step and before the base color resin layer forming step.

[0019] The above method may further include a pattern printing step of forming a pattern printed layer having a pattern printed thereon on the container body, the base color resin layer, or the other color resin layer.

[0020] The above method may further include a release film forming step of providing a peelable release film so as to be in direct contact with the other color resin layer.

[0021] In the above, the pattern shape may be provided at an area density of 3 to 15% of the pseudo base color region.

[0022] In the above, the pattern shape may include one or more shapes of a dot pattern, a line pattern, a random pattern, a barcode, and a two-dimensional code.

[0023] In the above, the pattern shape includes a shape in which the same or similar repeating units are repeated, and the length of the repeating unit may be 0.01 to 1 mm.

[0024] 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]

[0025] [Figure 1] An example of the metal container 10 of this embodiment is shown. [Diagram 2] An example of a layer structure 200 of the metal container 10 of this embodiment is shown. [Diagram 3] An example of a layer structure 300 of the metal container 10 of this embodiment is shown. [Figure 4] An example of a layer structure 400 of the metal container 10 of this embodiment is shown. [Diagram 5] An example of a layer structure 500 of the metal container 10 of this embodiment is shown. [Figure 6] 4 shows an example of a pattern of a pseudo base color region of the present embodiment. [Figure 7] 4 shows an example of a pattern of a pseudo base color region of the present embodiment. [Figure 8] 4 shows an example of a pattern of a pseudo base color region of the present embodiment. [Figure 9] An example of a flow of a method for manufacturing the metal container 10 of this embodiment will be shown. [Figure 10] An example of a sub-flow of S200 is shown. [Figure 11] Another example of the flow of the method for manufacturing the metal container 10 of this embodiment will be described. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] 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.

[0027] 1 shows an example of a metal container 10 according to the present embodiment. The metal container 10 is a metal container capable of holding contents. The metal container 10 may be used for the purpose of holding beverages or fluids, or may be used for the purpose of holding food.

[0028] The metal container 10 comprises a container body having an opening 12, a side wall 20, and a bottom 30. As shown in Fig. 1, the opening 12 is a ring-shaped portion of the container body in which an opening is formed. The side wall 20 forms the side wall of the container body and is cylindrical in shape. The bottom 30 forms the bottom of the container body and holds the contents from below.

[0029] In the metal container 10, the container body may have a cup-like shape that is used with the opening 12 open. The container body may have a shape in which the inner diameter is largest at the opening 12 and decreases toward the bottom 30. This makes it possible to stack the metal containers 10, and thus allows a plurality of metal containers 10 to be stored and transported in a stacked state.

[0030] As shown in FIG. 1, the container body may have a curled portion 40 around the periphery of the opening 12, which curves the end of the container body toward the outside in the radial direction of the container. The side wall portion 20 may have a shape that gradually reduces in diameter from the opening 12 to the bottom portion 30, either uniformly or in a stepped shape, and may have a cross-sectional shape that combines curved and straight lines. For example, the side wall portion 20 may have a shape that includes a bulging portion 50 that bulges outward. By having the bulging portion 50 in the container body, the metal containers 10 can be easily pulled apart when being separated from each other when they are stacked. The bottom portion 30 of the container body may have a dome-like shape that protrudes toward the opening 12 side.

[0031] There may be no clear boundaries between the opening 12, the sidewall 20, and the bottom 30. For example, the metal container 10 may have a bowl shape with the sidewall 20 and the bottom 30 integrated together.

[0032] The metal container 10 may be a cylindrical can container with a lid attached to the opening 12. The can container may be cylindrical in shape with an upper portion of the side wall portion 20 having a shape that tapers from the bottom portion 30 toward the opening 12. The can container may be bottle-shaped with the opening 12 provided at a narrow-diameter mouth portion.

[0033] The thickness of the metal container 10 may vary depending on the application. For example, the average thickness of the side wall 20 of the metal container 10 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.

[0034] A pattern 32 may be provided on a portion of the metal container 10 (e.g., the side wall portion 20). The pattern 32 may be formed by a pattern printed layer 140 described below. In the metal container 10, an area 34 where the pattern 32 is not formed becomes the base color. Such an area 34 is formed by a base color resin layer 120 and an other color resin layer 130 described below, and becomes a pseudo base color area.

[0035] 2 shows an example of a layer structure 200 of the metal container 10 of this embodiment. The metal container 10 includes a container body 110, a base color resin layer 120, an additional color resin layer 130, a pattern printed layer 140, and a release film 150.

[0036] The container body 110 may include a metal layer and a resin film layer covering one or both sides of the metal layer. In this example, the container body 110 is not a simple metal, but has a layer structure including a metal layer 112 as a core, and resin film layers 114 and 116 covering the inner and / or outer surfaces of the metal layer 112.

[0037] The metal layer 112 may be a plate-shaped metal sheet. The metal sheet may be made of a metal that is suitable for use with food, such as aluminum, an aluminum alloy, stainless steel, or steel. The thickness of the metal sheet may be 0.05 to 0.22 mm.

[0038] The resin film layer 114 and the resin film layer 116 may be a film made of a thermoplastic resin. The resin film layer 114 and the resin film layer 116 may be, for example, a polyethylene terephthalate (PET) film, a polyolefin film, and / or a polyester film. For example, the container body 110 may be formed by laminating a PET film to the inner and outer surfaces of a metal plate. These films may be stretched or unstretched. The resin film layer 114 and the resin film layer 116 may be a coating made of a thermosetting resin and / or a thermoplastic resin. Examples of paints that can be formed into a coating include polyester-based, acrylic-based, urethane-based, silicone-based, and fluorine-based paints.

[0039] By using the container body 110 covered with a resin film in this manner, it is possible to prevent the container body 110 from being corroded by the filling material. In addition, the amount of lubricant and water used during molding of the container body 110 can be reduced.

[0040] The base color resin layer 120 is a layer containing a base color resin that is uniformly provided as a base on the metal container 10. The base color resin layer 120 is formed on at least a portion of the surface of the container body 110. The base color resin layer 120 may be formed in a solid shape so as to cover a certain or larger wide area or the entire area of ​​the container body 110. As described below, a pseudo base color area is provided on at least a portion of the surface of the base color resin layer 120.

[0041] The base color resin layer 120 may be a layer of a cured base color resin formed directly on the container body 110. The base color resin layer 120 may contain a coloring material such as a pigment or a dye, a binder resin, and other solid components of the ink composition.

[0042] The base color resin layer 120 may be a radiation-curable resin obtained by curing an ink composition. The radiation may be infrared light, visible light, ultraviolet light, electromagnetic waves such as X-rays, or electron beams. For example, the ink composition may be a cured ultraviolet-curable resin or an electron beam-curable resin. For example, the ink composition may be an offset printing ink or an inkjet printing ink containing these radiation-curable resins.

[0043] The color of the coloring material may be the base color of the entire metal container 10, and may be appropriately selected according to the pattern, etc. For example, the coloring material may be transparent, white, black, gray, yellow, red, orange, green, blue, brown, pink, purple, etc., but is not limited to these. In particular, white is preferably used. For example, as a white coloring material, a white pigment such as titanium oxide, zinc oxide, calcium carbonate, kaolin, barium sulfate, etc. may be used. In the case of a coloring material other than white, a coloring material such as a yellow pigment or a magenta pigment may be appropriately selected and used depending on the color.

[0044] The other-color resin layer 130 is a resin layer that is formed in a predetermined pattern shape on the base-color resin layer 120 and contains a resin of a color other than the base color. On the surface of the metal container 10, the region where the other-color resin layer 130 is formed in a pattern shape on the base-color resin layer 120 becomes a pseudo-base-color region.

[0045] In the pseudo base color region, the other color resin layer 130 is present in a pattern on the base color resin layer 120. Therefore, to a user who picks up the metal container 10, the pseudo base color region appears to be a uniform color obtained by mixing the base color resin layer 120 and the other color resin layer 130.

[0046] The base color resin layer 120 and the pseudo base color region may be formed in a relatively similar color. This makes the other color resin layer 130 in the pseudo base color region less noticeable, and makes the pseudo base color region appear to be a uniform color. For example, the base color resin layer 120 may be white and the other color resin layer 130 may be yellow, making the pseudo base color region milky white.

[0047] The difference in color between the base color resin layer 120 and the pseudo base color region may be equal to or less than a certain level. For example, the color difference ΔE* in the L*a*b* color system between the base color resin layer 120 and the pseudo base color region may be equal to or less than 2.5, more preferably equal to or less than 2.0, and even more preferably equal to or less than 1.5. This allows the pseudo base color region to appear as a uniform color. When the color material of the base color resin layer 120 is transparent, the color of the base color resin layer 120 may be the color of the lower layer (container body 110) seen through the base color resin layer 120.

[0048] The difference in brightness between the base color resin layer 120 and the pseudo base color region may be equal to or less than a certain value. For example, when the base color resin layer 120 is white, the difference in L* value in the L*a*b* color system between the base color resin layer 120 and the pseudo base color region may be equal to or less than 2.5, more preferably equal to or less than 2.0, and even more preferably equal to or less than 1.5. This allows the pseudo base color region to appear as a uniform color.

[0049] The pseudo base color region may be formed on the entire surface of the base color resin layer 120. Alternatively, the pseudo base color region may be formed on a portion of the surface of the base color resin layer 120. In this case, the other color resin layer 130 may be formed only on a portion of the surface of the base color resin layer 120. In this case, nothing is formed on the other areas of the base color resin layer 120, or only the picture print layer 140 is formed.

[0050] The other color resin layer 130 may be a radiation cured resin cured on the base color resin layer 120. The components of the ink composition for forming the other color resin layer 130 may be the same as those used for the base color resin layer 120, or may be different.

[0051] The other-color resin layer 130 includes a resin of a color other than the base color. For example, the color of the color material included in the other-color resin layer 130 is different from the color of the color material included in the base color resin layer 120.

[0052] The pattern printed layer 140 is a layer that forms a pattern to be printed on the container body 110, the base color resin layer 120, or the other color resin layer 130. In FIG. 2, the pattern printed layer 140 is formed on the base color resin layer 120 together with the other color resin layer 130. The pattern printed layer 140 may be formed on the other color resin layer 130. By forming a pattern with the pattern printed layer 140 on a pseudo base color area that is visible as a base, the pattern can be made to stand out clearly. Also, the container body 110 can be protected by an inconspicuous layer.

[0053] The picture-printed layer 140 may be a cured radiation curable resin. The components of the ink composition for forming the picture-printed layer 140 may be the same as or different from those used in the base color resin layer 120. The picture-printed layer 140 may be a picture such as letters, figures, illustrations, identification codes, or a combination of these.

[0054] The release film 150 is a peelable film. The release film 150 is provided so as to be in direct contact with the other color resin layer 130. The release film 150 may be a tack seal or the like that is attached to the other color resin layer 130 with a weak adhesive strength that allows it to be peeled off by hand.

[0055] The release film 150 may have information such as a picture, a letter, and / or a code printed on the back side (the other-color resin layer 130 side) and / or the front side (i.e., the side opposite the other-color resin layer 130). The release film 150 may be a prize sticker. For example, the front side of the release film 150 may be printed with the words "If you get a winning entry on the back, give XXX to XXX person," and the back side may be printed with the words "winner" or "lose," or with information indicating a web link such as a QR code.

[0056] The release film 150 may be a substrate made of paper, a resin film, a metal film, or a combination of these, with an adhesive applied to one side thereof. The substrate may be printed. A known adhesive may be used. For example, an acrylic polymer, a silicone rubber, a polyurethane, a natural rubber, or a natural resin may be used. The adhesive may be applied to the substrate in an amount appropriate for the needs, for example, 15 to 25 g / 1 m. 2 The coating amount may be 100%.

[0057] As shown in the figure, according to this embodiment, the release film 150 may be fixed to the container body 110 not only via the base color resin layer 120 but also via the other color resin layer 130 .

[0058] When peeling off the release film 150, the adhesive strength of the release film 150 was too strong, and the underlying resin layer (e.g., the base color resin layer 120) peeled off together with the release film 150, which damaged the aesthetic appearance of the metal container 10. Peeling was particularly noticeable when the metal container 10 was wet with moisture due to condensation or the contents.

[0059] Here, the inventors have found that, compared to contact with only a single type of resin layer (for example, the base color resin layer 120), when contacting with multiple types of resin layers (for example, the base color resin layer 120 and the other color resin layer 130), it is possible to prevent the base from peeling off when the release film 150 is peeled off. This is because by using multiple types of resin layers as the base for the release film 150, even if one resin layer is easily peeled off, the other resin layer can compensate.

[0060] On the other hand, if the colors of the base color resin layer 120 and the other color resin layer 130 are too different, it will not function as a base color region. Therefore, as described above, by forming the base color resin layer 120 and the pseudo base color region in similar colors, it is possible to prevent the base from peeling off while ensuring an appearance that is less unnatural as a base color.

[0061] In particular, when the base color resin layer 120 is white and / or formed by inkjet printing, the adhesion between the release film 150 and the base color resin layer 120 is strong and tends to peel off easily. Therefore, the degree of prevention of peeling is even more remarkable when the base color resin layer 120 is white and / or formed by inkjet printing. This is because, when the base color resin layer 120 is white and / or formed by inkjet printing, it is designed so that ink of other colors is less likely to run over it compared to other cases, and the adhesion with the release film 150 is particularly high, but by using a color other than white, which has low adhesion, for the other color resin layer 130, the adhesion with the release film 150 can be reduced.

[0062] 3 shows an example of a layer structure 300 of the metal container 10 of this embodiment. In this example, unlike FIG. 2, the container body 110 is made of only one metal layer, not three layers of the metal layer 112, the resin film layer 114, and the resin film layer 116. The metal layer forming the container body 110 may be the same as the metal layer 112 described in FIG. 2.

[0063] 4 shows an example of a layer structure 400 of the metal container 10 of this embodiment. In this example, the picture-printed layer 140 is formed directly on the container body 110 consisting of three layers, the metal layer 112, the resin film layer 114, and the resin film layer 116. This makes it possible to reduce the formation area of ​​the base color resin layer 120 and the other color resin layer 130. Although not shown, the picture-printed layer 140 may be further formed on the base color resin layer 120 and the other color resin layer 130.

[0064] 5 shows an example of a layer structure 500 of the metal container 10 of this embodiment. In this example, unlike FIG. 4, the container body 110 is made of only one metal layer, not three layers of the metal layer 112, the resin film layer 114, and the resin film layer 116. The metal layer forming the container body 110 may be the same as the metal layer 112 described in FIG. 2.

[0065] 6 shows an example of a pattern of the pseudo base color region of this embodiment. The other color resin layer 130 may be formed in various pattern shapes. For example, the pattern shape of the other color resin layer 130 is not particularly limited, and may include one or more shapes of a dot pattern, a line pattern, a random pattern, a barcode, and a two-dimensional code.

[0066] The pattern shape may include a shape in which the repeating units of the same or similar shape are repeated at regular or irregular intervals. In such a case, the other color resin layer 130 can be further blended into the base color resin layer 120 without being conspicuous in the pseudo base color area.

[0067] When the repeating unit is repeated at regular intervals, the length of the repeating unit may be 0.01 to 1 mm. In the case of a dot pattern, the distance between adjacent other color resin layers 130 may be 0.01 to 1 mm. In the case of a dot pattern, the maximum diameter of the dots in the other color resin layer 130 may be 0.01 to 1 mm.

[0068] 6, the base color resin layer 120 is formed on one surface (i.e., solidly), and the other color resin layer 130 is formed in a regular dot pattern (in the figure, a pattern in which round dots are repeated at a constant interval of distance D). For example, distance D may be 0.01 to 1 mm.

[0069] 7 shows an example of a pattern of the pseudo base color region of this embodiment. In this example, the other color resin layer 130 is formed in a random pattern in which dots are randomly arranged on the base color resin layer 120 formed on one surface (i.e., solid). By forming the other color resin layer 130 randomly, it is possible to prevent moire from occurring and becoming easily visible.

[0070] 8 shows an example of a pattern of the pseudo base color region of this embodiment. In this example, the other color resin layer 130 is formed in a line pattern in which lines are arranged at equal intervals on the base color resin layer 120 formed on one surface (i.e., solid). The line intervals of the line pattern may be random.

[0071] Fig. 9 shows an example of a flow of the manufacturing method of the metal container 10 of this embodiment. By executing the flow from S100 to S600 in Fig. 9, the manufacturing method of the metal container 10 is performed, which includes a sheet material forming step, a molding step, a base resin layer forming step, a different color resin layer forming step, a picture print forming step, and a release film forming step.

[0072] For ease of explanation, the processes from S100 to S600 will be explained in order. However, at least some of these processes may be executed in parallel, or the steps may be interchanged and executed without departing from the spirit of the present invention. Some steps may be omitted and executed without departing from the spirit of the present invention.

[0073] First, in S100, a sheet material is formed for forming the container body 110. A resin film is formed on one or both sides of a metal sheet to form a sheet material having a metal sheet and a resin film layer covering at least one side of the metal sheet.

[0074] The metal sheet may be formed by cutting a metal plate material wound into a coil shape. A resin film layer may be formed on the metal sheet by extrusion coating, cast film heat bonding, biaxially stretched film heat bonding, or the like.

[0075] The metal plate may be made of aluminum, aluminum alloy, stainless steel, or steel. The thickness of the metal sheet may be 0.05 to 0.22 mm. The resin film may be a resin film such as a polyethylene terephthalate (PET) film. Instead of using a laminate of a metal sheet and a resin film as the sheet material, a sheet material having only the metal sheet may be obtained by using a metal sheet alone.

[0076] Next, in S200, the sheet material obtained in S100 is molded into a container body 110 having an opening 12, a side wall portion 20, and a bottom portion 30. The molding may be performed by a known molding method according to the shape of the container body 110. The above description of the container body may be applied as it is.

[0077] Fig. 10 shows an example of a sub-flow of S200. The molding step of S200 may be performed by executing S210 to S250 in Fig. 10.

[0078] First, in S210, the sheet material of S100 is punched and subjected to drawing and / or ironing to form a cup-shaped bottomed cup. In S210, the drawing and / or ironing may be performed multiple times depending on the shape of the container body.

[0079] Next, in S220, the tip of the bottomed cup formed in S210 is trimmed. In S220, the tip height of the bottomed cup, which has become uneven due to drawing and / or ironing processes, is cut evenly around the central axis to make the tip height of the bottomed cup after trimming uniform.

[0080] Next, in S230, the trimmed tip of the bottomed cup is subjected to tip diameter reduction processing. In S230, as the diameter reduction processing for the tip, the tip opening of the bottomed cup is gradually reduced in diameter toward the tip.

[0081] Next, in S240, the tip opening of the bottomed cup is curled or flanged to form the opening 12.

[0082] Next, in S250, the diameter is gradually reduced from the tip end portion reduced in S230 toward the bottom portion 30, thereby forming the side wall portion 20 having an overall tapered contour.

[0083] By the subflow shown in Fig. 10, a cup-shaped container body 110 having an opening 12, a side wall 20, and a bottom 30 is formed as shown in Fig. 1. After the steps according to the subflow are completed, the process proceeds to S300.

[0084] In S300, a base color resin layer forming step is performed to form a base color resin layer 120 containing a base color resin on at least a portion of the surface of the container body 110. For example, the base color resin layer 120 may be formed on the side wall portion 20 of the container body 110. The base color resin layer 120 may be formed on the entire surface of the container body 110, or alternatively, the base color resin layer 120 may be formed on only a portion of the surface of the container body 110 as shown in FIG.

[0085] The base color resin layer forming step may be performed by inkjet printing using an inkjet printer. Alternatively, the base color resin layer forming step may be performed by plate printing using a plate printing machine (for example, offset printing, screen printing, flexographic printing, or gravure printing using a gravure roller). The base color resin layer forming step may be performed by applying the resin to the entire outer surface of the container body 110 using a coater or the like.

[0086] The printing may be performed using the ink composition described in the description of the base color resin layer 120. For example, a radiation curable ink may be applied to the resin film layer 116 as the ink composition.

[0087] In particular, in the base color resin layer forming step, printing may be performed using an ink composition containing a color material that will be a base color such as white. After printing, the ink composition is irradiated with radiation (ultraviolet rays, electron beams, etc.) to harden the ink, thereby forming the base color resin layer 120.

[0088] The base color resin layer 120 may be formed by one printing and curing process, or alternatively, the base color resin layer 120 may be formed by multiple printing and curing processes.

[0089] Next, in S400, an other color resin layer forming process is performed to form an other color resin layer 130 on the base color resin layer 120 formed in S300. The other color resin layer 130 may be formed in a predetermined pattern shape on at least a portion (all or a part) of the surface of the base color resin layer 120.

[0090] Of the regions where the base color resin layer 120 is provided, the region where the pattern shape of the other color resin layer 130 is provided becomes a pseudo base color region that functions as a background of a picture, etc. Note that the pseudo base color region does not refer to a very narrow region where the base color resin layer 120 and the other color resin layer 130 completely overlap, but refers to a region of the wide region where the base color resin layer 120 is provided that is covered by the pattern of the other color resin layer 130 (and the blank space between them). For example, the entire region shown in Figures 6 to 8 is a pseudo base color region.

[0091] The other-color resin layer forming step may be performed by inkjet printing using an inkjet printer. Alternatively, the other-color resin layer forming step may be performed by plate printing using a plate printing machine (e.g., offset printing, screen printing, flexographic printing, or gravure printing using a gravure roller).

[0092] The printing may be performed using the ink composition described in the description of the other color resin layer 130. For example, a radiation curable ink may be used as the ink composition.

[0093] In particular, in the other-color resin layer forming step, printing may be performed using an ink composition containing a color material of a color close to the base color (in the case of white), such as yellow. After printing, the ink composition is irradiated with radiation (e.g., ultraviolet light or electron beam) to cure the ink, thereby forming the other-color resin layer 130.

[0094] The pattern shape of the other-color resin layer 130 may be a combination of geometric shapes. For example, the pattern shape may be one or more of a dot pattern, a line pattern, a random pattern, a barcode, and a two-dimensional code. The pattern shape of the other-color resin layer 130 may be provided at an area density of 3 to 15%, preferably 3 to 12%, and more preferably 3 to 8% of the pseudo base color region. In the case of plate printing, the pattern shape may be expressed by, for example, halftone dots.

[0095] The pattern shape may include a shape in which repeating units of the same or similar shape are repeated at regular or irregular intervals. When the repeating units are repeated at regular intervals, the length of the repeating units may be 0.01 to 1 mm.

[0096] The other color resin layer 130 may be formed to have a pattern shape according to the patterns described in Figures 6 to 8 or other patterns. The other color resin layer 130 may be formed so that, after curing, the color difference ΔE* (for example, CIE ΔE1994 or CIE ΔE2000) in the L*a*b* color system between the base color resin layer 120 and the pseudo base color region is 2.5 or less, more preferably 2.0 or less, and even more preferably 1.5 or less. This allows the pseudo base color region to appear as a uniform color.

[0097] After curing, the other color resin layer 130 may have a difference in L* value in the L*a*b* color system between the base color resin layer 120 and the pseudo base color region of 2.5 or less, more preferably 2.0 or less, and even more preferably 1.5 or less. This allows the pseudo base color region to appear as a uniform color.

[0098] The difference in color difference ΔE and L* value can be adjusted by the color of the base color resin layer 120, the color of the other color resin layer 130, and the area ratio of the other color resin layer 130 formed on the base color resin layer 120. For example, the closer the colors of the base color resin layer 120 and the other color resin layer 130 are and / or the smaller the area ratio of the other color resin layer 130 is, the smaller the difference in color difference ΔE and L* value can be.

[0099] The other-color resin layer 130 may be formed by printing and curing once. Alternatively, the other-color resin layer 130 may be formed by printing and curing multiple times.

[0100] Table 1 shows the measurement results of L*a*b*, etc. when only the base color resin layer 120 formed with white inkjet ink is formed on the container body 110. Table 2 shows the actual area density and measurement results of L*a*b*, etc. of the other color resin layer 130 on the printed matter when the other color resin layers 130 of each color of CMY are formed on the base color resin layer 120 at an area density of 1 to 3% on the print data to form a pseudo base color area. Table 3 shows the difference between the pseudo base color area and the base color resin layer 120 (L* value (ΔL*) of L*a*b*, etc.).

[0101] [Table 1] [Table 2] [Table 3]

[0102] In the examples where the other-color resin layer 130 of each of the above CMY colors is formed with an area density of 1 to 3% on the print data (3 to 12% on the print), the pattern of the other-color resin layer 130 is not very noticeable in the pseudo base color area and functions adequately as a background. In all of these examples, the difference in L* (absolute value of ΔL*) is 2.5 or less. ΔE* means CIE ΔE1994.

[0103] Furthermore, for 1% yellow (Y), 1% magenta (M), and 1% cyan (C), which had a color difference ΔE* (ΔE2000) of 2.5 or less in the L*a*b* color system, the other-color resin layer 130 was even less noticeable. In particular, for 1% yellow (Y), which had a ΔE* (ΔE2000) of 1 or less, the other-color resin layer 130 was completely unnoticeable unless viewed from a close distance.

[0104] Next, in S500, a pattern printing forming process is performed to form a pattern-printed layer 140 on which a pattern is printed. The pattern-printed layer 140 may be provided at any location on the metal container 10. For example, the pattern-printed layer 140 may be formed on the container body 110, the base color resin layer 120, and / or the other color resin layer 130.

[0105] The picture print forming step may be performed by inkjet printing using an inkjet printer. Alternatively, the picture print forming step may be performed by plate printing using a plate printing machine (e.g. offset printing, screen printing, flexographic printing, or gravure printing using a gravure roller).

[0106] The printing may be performed using the ink composition described in the description of the other color resin layer 130. For example, a radiation curable ink may be used as the ink composition. The picture-printed layer 140 may be formed by printing and curing once. Alternatively, the picture-printed layer 140 may be formed by printing and curing multiple times.

[0107] In the above example, the step of forming the other-color resin layer S400 and the step of forming the picture print S500 are described as separate steps, but the step of forming the picture print may be performed simultaneously with the step of forming the other-color resin layer. For example, the other-color resin layer 130 and the picture print layer 140 may be formed simultaneously by inkjet printing.

[0108] Next, in S600, a release film forming step is performed in which a peelable release film 150 is provided so as to be in direct contact with the other color resin layer 130. For example, the release film 150 may be provided in the pseudo base color region. This results in the release film 150 being in direct contact with the other color resin layer 130. The release film 150 may be the same as that described above.

[0109] Thus, according to this embodiment, a pseudo base color region is formed by combining the base color resin layer 120 and the other color resin layer 130 having a pattern shape, and the release film 150 is provided on the pseudo base color region. This makes it possible to prevent the release film 150 from adhering too closely to the base layer, causing it to peel off, compared to a case in which the release film 150 is provided only on the base color resin layer 120.

[0110] Also, as explained in Tables 1 to 3, in a metal container in which the other-color resin layers 130 of each of the CMY colors were formed with an area density of 1 to 3% on the print data (3 to 12% on the print), and the release film 150 was formed, the base did not peel off when the release film was peeled off. Specifically, in the case of only the base color resin layer in Table 1, when the immersion time in water exceeded 180 minutes, a certain degree of failure occurred in which the release film peeled off the base (base color resin layer) in the peeling test after immersion, but in an example in which the other-color resin layers 130 of each of the CMY colors were formed with an area density of 1 to 3% on the print data (3 to 12% on the print data), no peeling failure occurred even when the immersion time exceeded 20 hours.

[0111] The sheet material forming step S100 may be omitted. In this case, the container body 110 will have only one layer, the metal layer, as shown in Fig. 3. Even in this case, the provision of the other-color resin layer 130 can provide a certain degree of prevention of peeling.

[0112] 11 shows another example of the flow of the method for manufacturing the metal container 10 of this embodiment. In this embodiment, after the molding step S200 and before the base color resin layer forming step S300, a surface modification treatment for modifying the surface of the resin film layer 116 is included.

[0113] In the surface modification treatment, at least a part of the surface of the resin film layer 116 of the container body 110 after molding in S200 is modified. For example, one or more of a flame treatment, a corona treatment, and an atmospheric pressure plasma treatment may be performed, in which at least a part of the surface of the resin film layer 116 is brought into contact with a flame to modify the surface.

[0114] The surface free energy of the surface of the resin film layer 116 after the surface modification treatment may be 44 mN / m or more and less than 60 mN / m. The surface free energy of the resin film layer 116 may be 46 mN / m or more and less than 57 mN / m. The surface free energy may be measured by the OWRK method using a double drop handy contact angle and surface free energy analyzer manufactured by KRUSS. By performing the surface modification treatment so that the surface free energy of the surface of the resin film layer 116 falls within this range, the adhesion between the base color resin layer 120 and the pattern printed layer 140, etc. and the resin film layer 116 can be improved. Furthermore, the water resistance of the metal container 10 including the pattern printed layer 140, etc. can be improved.

[0115] When the surface modification treatment includes a flame treatment, the ratio of fuel gas to combustion air used to generate the flame that is brought into contact with the surface of the resin film layer 116 may be 1:10 to 1:30.

[0116] The flame treatment may be performed by adjusting the amounts of fuel gas and combustion air used to generate the flame and / or the ratio of fuel gas and combustion air according to the treatment time during which the flame is in contact with at least a portion of the surface of the resin film layer 116. By adjusting the amounts of fuel gas and combustion air used to generate the flame and the ratio of fuel gas and combustion air according to the treatment time during which the flame is in contact with the surface of the resin film layer 116, the surface free energy of the surface of the resin film layer 116 after the surface modification treatment can be adjusted to be within the above range.

[0117] In the above description, the present embodiment has been described with reference to the metal container 10, but the manufacturing method of the present embodiment may be applied to containers other than those made of metal. For example, at least some of the above-described surface modification process, base resin layer forming process, other color resin layer forming process, picture print forming process, and release film forming process may be applied to a resin cup-shaped container.

[0118] 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.

[0119] 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]

[0120] 10 metal container 12 Opening 20 Side wall 30 bottom 32 Design 34 areas 40 Curl section 50 Bulge 110 Container body 112 Metal layer 114 Resin film layer 116 Resin film layer 120 Base color resin layer 130 Other color resin layer 140 Pattern printing layer 150 Release film 200 layer configuration 300 layer configuration 400 layer configuration 500 layer configuration

Claims

1. a container body having an opening, a sidewall and a bottom; a base color resin layer including a base color resin formed on at least a portion of the surface of the container body; a second color resin layer including a resin of a color other than the base color formed in a predetermined pattern shape in a pseudo base color region provided on at least a part of the surface of the base color resin layer; Equipped with a color difference ΔE* between the base color resin layer and the pseudo base color region in the L*a*b* color system is 2.5 or less; metal container.

2. The base color resin layer is white.

2. The metal container according to claim 1.

3. a difference in L* value in the L*a*b* color system between the base color resin layer and the pseudo base color region is 2.5 or less; The metal container according to claim 2.

4. The pseudo base color region is formed on the entire surface of the base color resin layer. The metal container according to claim 1.

5. The pattern shape includes one or more shapes of a dot pattern, a line pattern, a random pattern, a bar code, and a two-dimensional code. The metal container according to claim 1.

6. The pattern shape includes a shape in which repeat units of the same or similar shape are repeated, The length of the repeating unit is 0.01 to 1 mm. The metal container according to claim 5.

7. The pattern shape is provided at an area density of 3 to 15% of the pseudo base color area. The metal container according to claim 1.

8. The base color resin layer is a cured radiation cured resin. The metal container according to claim 1.

9. The container further includes a pattern printed layer on which a pattern is printed on the container body, the base color resin layer, or the other color resin layer. The metal container according to claim 1.

10. The ink jet recording medium further includes a peelable release film provided so as to be in direct contact with the other color resin layer. The metal container according to claim 1.

11. The container body includes a metal layer and a resin film layer covering one or both sides of the metal layer. The metal container according to claim 1.

12. The average thickness of the side wall of the metal container is 0.08 to 0.22 mm. The metal container according to claim 1.

13. a base color resin layer forming step of forming a base color resin layer containing a base color resin on at least a part of a surface of a container body having an opening, a side wall, and a bottom; a step of forming an other-color resin layer, the other-color resin layer including a resin of a color other than the base color and formed in a predetermined pattern shape on the pseudo base color region provided on at least a part of the surface of the base color resin layer; Equipped with a color difference ΔE* between the base color resin layer and the pseudo base color region in the L*a*b* color system is 2.5 or less; A method for manufacturing metal containers.

14. The base color resin layer forming step and / or the other color resin layer forming step are performed by inkjet printing. The method of claim 13.

15. The method further includes a molding step of molding the container body 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 base color resin layer forming step and the other color resin layer forming step include applying a radiation curable ink to the resin film layer, The method of claim 13.

16. A surface modification treatment for modifying the surface of the resin film layer after the molding step and before the base color resin layer forming step is included. The method of claim 15.

17. The container body, the base color resin layer, or the other color resin layer may further include a pattern printing step of forming a pattern printing layer having a pattern printed thereon. The method of claim 13.

18. The method further includes a release film forming step of providing a release film that can be peeled off so as to be in direct contact with the other color resin layer. The method of claim 13.

19. The pattern shape is provided at an area density of 3 to 15% of the pseudo base color area. The method of claim 13.

20. The pattern shape includes one or more shapes of a dot pattern, a line pattern, a random pattern, a bar code, and a two-dimensional code. The method of claim 13.

21. The pattern shape includes a shape in which repeat units of the same or similar shape are repeated, The length of the repeating unit is 0.01 to 1 mm. The method of claim 20.

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