Can container

Abstract

To prevent scratches when forming a diameter-reduced part, and to provide a manufacturing method of a can container capable of preventing metal powder from being attached to a die.SOLUTION: According to a first embodiment of the present invention relating to a manufacturing method of a can container comprising a cylindrical can body, there is provided the manufacturing method of a can container, that comprises the steps of: forming a surface coating layer on at least part of an outer peripheral face of the can body by coating a varnish containing a wax component, or coating the varnish containing the wax component after forming the surface coating layer by coating at least the part of the outer peripheral face of the can body with a resin film to form an additional varnish layer; reducing the diameter of at least part of a portion where the surface coating layer is formed out of the can container; and eliminating at least part of the wax component contained in the surface coating layer or the additional varnish layer by washing the can container.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a can container. [Background technology]

[0002] In can containers such as beverage cans, it is common to form a tapered portion at the end of the can body on the opening side. It is known that applying varnish to the surface of the can body before forming the tapered portion can prevent scratches on the can body and metal powder from adhering to the mold used to form the tapered portion.

[0003] Patent Document 1 describes printing after forming a reduced diameter portion on a can body and applying varnish before forming the reduced diameter portion. Patent Document 2 describes forming an image by inkjet after forming a base layer by overburnishing or the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-025521 [Patent Document 2] Japanese Patent Application Publication No. 2019-108138 Summary of the Invention

[0005] In a first aspect of the present invention, a can is provided, comprising a cylindrical can body and at least a surface coating layer, the surface coating layer being formed on at least a part of the outer peripheral surface of the can body, the surface coating layer containing a resin component, and the surface free energy of the surface of the surface coating layer being 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 The following can container is provided:

[0006] In a second aspect, there is provided a method for manufacturing a can container having a cylindrical can body and at least a surface coating layer, the method comprising: applying a varnish containing a resin component and a wax component to at least a part of the outer periphery of the can body; or coating at least a part of the outer periphery of the can body with a resin film to form a can container having a surface free energy of 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 The present invention provides a method for manufacturing a can container, comprising the steps of: forming the surface coating layer; and reducing the diameter of at least a portion of the portion of the can container where the surface coating layer is formed.

[0007] In a third aspect, there is provided a method for manufacturing a can container having a cylindrical can body and at least a surface coating layer, the method comprising: applying a varnish containing a resin component and a wax component to at least a part of the outer periphery of the can body; or coating at least a part of the outer periphery of the can body with a resin film to form a surface coating layer having a surface free energy of 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 The present invention provides a method for manufacturing a can container, comprising the steps of: forming the surface coating layer; reducing the diameter of at least a portion of the portion of the can container where the surface coating layer is formed; and printing an ink composition to form a printed image layer.

[0008] In addition, in a fourth aspect, there is provided a method for manufacturing a can container having a cylindrical can body, comprising the steps of applying a varnish containing a wax component to at least a portion of the outer surface of the can body to form a surface coating layer, or coating at least a portion of the outer surface of the can body with a resin film to form a surface coating layer, and then applying a varnish containing a wax component to form an additional varnish layer; reducing the diameter of at least a portion of the portion of the can container where the surface coating layer is formed; and heating the can container to evaporate at least a portion of the wax component contained in the surface coating layer or the additional varnish layer.

[0009] In addition, in a fifth aspect, there is provided a method for manufacturing a can container having a cylindrical can body, comprising the steps of applying a varnish containing a wax component to at least a portion of the outer surface of the can body to form a surface coating layer, or coating at least a portion of the outer surface of the can body with a resin film to form a surface coating layer, and then applying a varnish containing a wax component to form an additional varnish layer; reducing the diameter of at least a portion of the portion of the can container where the surface coating layer is formed; and washing the can container to remove at least a portion of the wax component contained in the surface coating layer or the additional varnish layer.

[0010] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also be inventions. [Brief explanation of the drawings]

[0011] [Figure 1] 1 shows an example of a sketch of a can container before an image is printed in this embodiment. [Figure 2] 10 shows an example of a sketch of a can container after an image is printed in this embodiment. [Figure 3] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 4] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 5] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 6] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 7] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 8] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 9] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 10] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 11] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 12] 1 shows an example of the overall layer structure of a can container in this embodiment. [Figure 13] 1 shows an example of a flow of a manufacturing method of a can container by wet molding according to this embodiment. [Figure 14] An example of the wet molding flow of S10 in this embodiment will be described. [Figure 15] 1 shows an example of a flow of a manufacturing method of a can container by dry molding according to this embodiment. [Figure 16] 10 shows an example of the flow of dry molding in S110 in this embodiment. [Figure 17] An example of a flow for forming a base image layer in this embodiment will be described. [Figure 18] An example of a flow for forming an ink-repellent varnish layer in this embodiment will be described below. [Figure 19] An example of a flow for forming an additional varnish layer in this embodiment will be described below. [Figure 20] An example of a flow for forming a receiving layer in this embodiment will be described below. [Figure 21] An example of a flow for heating and evaporating the wax component in this embodiment will be described below. [Figure 22] An example of a flow for cleaning and removing wax components in this embodiment will be described below. [Figure 23] An example of a flow for forming a protective layer in this embodiment will be described. [Figure 24] 10 shows a modified example of the flow of the method for manufacturing can containers in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0013] 1 shows an example of a schematic diagram of a can container 50 according to this embodiment before an image is printed. The can container 50 according to the present invention does not repel ink during printing, even after a surface coating layer is formed, allowing printing of excellent image quality. The can container 50 has a reduced diameter portion 100 provided at one end and a can body portion 200 provided at the other end.

[0014] The reduced diameter portion 100 is a portion where one end of the can container 50 has a reduced diameter. The reduced diameter portion 100 may be provided at the opening of the can container 50. By providing the reduced diameter portion 100 on the can container 50, the amount of can lids used to attach to the opening of the can container 50 can be reduced.

[0015] The reduced diameter portion 100 may be formed by necking the can container 50. The reduced diameter portion 100 may be formed so that the outer diameter gradually decreases toward one end of the can container 50. The reduced diameter portion 100 may also have a flange formed simultaneously with the necking. A can lid can be attached via the formed flange.

[0016] The can body 200 is a portion of the can container 50 other than the narrowed diameter portion 100. The can body 200 may include a bottom portion. The can body 200 may be provided on the bottom side of the can container 50. The can body 200 may have a substantially constant outer diameter in the longitudinal axis direction of the can container 50. The can body 200 may be narrowed on the bottom side of the can container 50. The can body 200 has a larger outer surface area than the narrowed diameter portion 100 and has a substantially constant outer diameter. Therefore, the can body 200 is suitable for applications in which printing is performed on the surface of the can container 50.

[0017] FIG. 2 shows an example of a sketch of a can container 50 after an image is printed in this embodiment. The can container 50 may have a reduced diameter portion 100 provided at one end, a can body portion 200 provided at the other end, and a printed portion 300. The printed portion 300 is an area printed using an ink composition on at least a portion of the outer periphery of the can container 50. The printed portion 300 may be provided on the can body portion 200 of the can container 50. The printed portion 300 may also be provided on the reduced diameter portion 100 of the can container 50 (not shown).

[0018] 3 shows an example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may have a can body 1, a surface coating layer 2, and a printed image layer 3 as its layer structure.

[0019] The can body 1 is the main body of the can container 50 and contains most of the contents. The can body 1 is formed in a cylindrical shape and has an outer peripheral surface. The can body 1 may be either a seamless can or a welded can. The material of the can body 1 may be either an aluminum can or a steel can, but is not limited to these.

[0020] The surface coating layer 2 serves to improve the slipperiness of the can container 50 when forming the reduced diameter portion 100 in the can container 50. The surface coating layer 2 may be provided on at least a part of the outer circumferential surface of the can body 1. The surface coating layer 2 may be provided at least on the reduced diameter portion 100 of the can container 50.

[0021] The surface coating layer 2 may contain a varnish, and the varnish contained in the surface coating layer 2 may contain at least a resin component. The varnish may contain at least a wax component. The varnish may contain both a resin component and a wax component. The varnish may contain, as a resin component, a thermosetting acrylic resin, a thermosetting epoxy resin, or a thermosetting polyester resin, but is not limited to these. The varnish may contain, as a wax component, an olefin hydrocarbon, a paraffin hydrocarbon, oils and fats, a synthetic polymer resin, or an organic fluorine compound, but is not limited to these.

[0022] The varnish contained in the surface coating layer 2 may not contain a leveling agent. A leveling agent is an additive that has the effect of smoothing the surface when applied to the surface, and examples of such additives include antifoaming agents, anti-cising agents, fluorine-based compounds, and silicon-based compounds.

[0023] The surface coating layer 2 may also be a layer coated with a resin film. The resin may be a polyester resin. For example, the resin film is a polyethylene terephthalate resin.

[0024] When the surface coating layer 2 is a resin film, the can body 1 and the surface coating layer 2 may be bonded together using an adhesive. The adhesive may be transparent or colored. For example, an acrylic resin adhesive, a urethane resin adhesive, a polyester resin adhesive, or the like may be used. As an example, a polyester resin adhesive is preferably one that uses a polyester resin as the base resin and a phenol resin, an amino resin, or an isocyanate resin as the curing agent.

[0025] Since the varnish contained in the surface coating layer 2 does not contain a leveling agent, the surface free energy of the surface of the surface coating layer 2 is 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 Furthermore, since the surface coating layer 2 is a layer coated with a resin film, the surface free energy of the surface of the surface coating layer 2 may be 30 mJ / m or less at a temperature of 25°C. 2 More than 50mJ / m 2 If the surface free energy of the surface of the surface coating layer 2 is in the above range, ink can be prevented from being repelled even when printing is performed on the surface coating layer 2. If the surface free energy of the surface of the surface coating layer 2 is 30 mJ / m at a temperature of 25°C, 2 If the surface free energy of the surface of the surface coating layer 2 is less than 50 mJ / m at a temperature of 25°C, the surface will not wet well and may repel ink, resulting in a deterioration in image quality. 2If the amount exceeds this, the surface becomes more wettable, which may cause the ink to bleed and result in a deterioration in image quality. The surface free energy of the surface of the surface coating layer 2 may be adjusted by flame treatment, plasma treatment, corona treatment, ITO treatment, etc.

[0026] The surface free energy of the surface of the surface coating layer 2 can be calculated based on the contact angle measured using a contact angle meter in accordance with JIS R 3257:1999 (IEC62073). Specifically, the measurement can be performed by the following procedure. 1) The contact angles of pure water and methylene iodide are measured in accordance with JIS R 3257:1999 "Testing method for wettability of substrate glass surfaces." A contact angle meter (DropMaster DM500, manufactured by Kyowa Interface Science Co., Ltd.) may be used as the measuring device. 2) Using the contact angle value obtained, calculate the surface free energy using the following Kaelble-Uy equation. γs=γs d +γs p γw(1+cosθw)=2(γs d γw d ) 1 / 2 +2(γs p γw p ) 1 / 2 γi(1+cosθi)=2(γs d γi d ) 1 / 2 +2(γs p γi p ) 1 / 2 where γs is the surface free energy of the surface, γs d is the dispersion component of the surface free energy of the surface, γs p is the polar component of the surface free energy of the surface, and γw is 72.8 mJ / m 2 , γw d is 21.8 mJ / m 2 , γw p is 51.0 mJ / m 2 , γi is 50.8 mJ / m 2 , γi d is 48.5 mJ / m 2 , γi pis 2.3 mJ / m 2 , θw is the contact angle of water on the surface, and θi is the contact angle of methylene iodide on the surface. d , γw p , γi, γi d , and γi p is a known literature value.

[0027] Since the varnish contained in the surface coating layer 2 does not contain a leveling agent, the kinetic friction coefficient of the surface of the surface coating layer 2 may be 0.30 or less. Furthermore, since the surface coating layer 2 is a layer coated with a resin film, the kinetic friction coefficient of the surface of the surface coating layer 2 may be 0.30 or less. Having the kinetic friction coefficient of the surface of the surface coating layer 2 within the above range prevents ink from being repelled when printing on the surface coating layer 2. If the kinetic friction coefficient of the surface of the surface coating layer 2 exceeds 0.30, the slipperiness between the surface coating layer 2 and the processing tool during necking may be poor, causing the load during forming to be unevenly applied to the processed portion, potentially resulting in buckling of the can body 200. Furthermore, if the kinetic friction coefficient of the surface coating layer 2 exceeds 0.30, the slipperiness between the surface coating layer 2 and the conveying guide or adjacent can containers 50 during transport of the can containers may be poor, potentially resulting in clogging or poor flow in the can container 50 production line or the subsequent content filling line.

[0028] The dynamic friction coefficient of the surface of the surface coating layer 2 may be measured in accordance with JIS K 7125:1999. A heating friction coefficient measuring instrument AB-550-TS (manufactured by Tester Sangyo Co., Ltd.) may be used as a measuring device for the dynamic friction coefficient. A test piece of a can container 50 on which the surface coating layer 2 is formed may be used as the fixed test piece, and a stainless steel ball with a diameter of 10 mm may be used as the moving test piece. The dynamic friction coefficient can be measured by applying a load of 1 N to the moving test piece using a weight and moving the moving test piece over a distance of 100 mm at a sliding speed of 150 mm / min.

[0029] The thickness of the surface coating layer 2 may be 0.5 μm or more and 15 μm or less. Preferably, the thickness of the surface coating layer 2 may be 1 μm or more and 10 μm or less. More preferably, the thickness of the surface coating layer 2 may be 2 μm or more and 6 μm or less. When the thickness of the surface coating layer 2 is within the above range, smoothness is ensured when forming the reduced diameter portion 100 on the can container 50, and printing with excellent image quality can be performed.

[0030] If the thickness of the surface coating layer 2 is less than 0.5 μm, the surface of the surface coating layer 2 will be less slippery, and there is a risk that the can container 50 will be scratched or that metal powder will adhere to the can container 50 when forming the reduced diameter portion 100 in the can container 50. If the thickness of the surface coating layer 2 exceeds 15 μm, more material will be required, which may increase costs and affect productivity, such as requiring a slower production speed.

[0031] The surface coating layer 2 may be formed by applying and baking varnish to the outer peripheral surface of the can body 1. The varnish may be applied to all or at least a part of the outer peripheral surface of the can body 1. Baking may be performed by hot air, ultraviolet irradiation, or electron beam irradiation.

[0032] By providing the surface coating layer 2, it is possible to prevent the can container 50 from being scratched when forming the reduced diameter portion 100 in the can container 50, and to prevent metal powder from adhering to the mold when reducing the diameter of the can container 50. Furthermore, when the surface coating layer 2 is a resin film, the can container 50 has the effect of excellent adhesion between the can body 1 and the printed image layer 3 provided on the surface coating layer 2 due to the softness and flexibility of the resin of the surface coating layer 2.

[0033] The printed image layer 3 is a layer of an image that expresses characters, pictures, etc. on the outer surface of the can container 50. The printed image layer 3 may be provided on the surface coating layer 2. The printed image layer 3 may constitute a printed portion 300 on the can container 50.

[0034] The printed image layer 3 may be a layer printed on the can container 50 using an ink composition. The ink composition may be, but is not limited to, an aqueous ink, a solvent ink, an ultraviolet curable ink, or an electron beam curable ink. The image formed on the printed image layer 3 may be a color image using ink compositions of multiple colors. The image formed on the printed image layer 3 may be a monochrome image using an ink composition of one color.

[0035] For example, the printed image layer 3 may be provided by inkjet printing on the surface coating layer 2. As an example, the printed image layer 3 is provided by direct inkjet printing on the surface coating layer 2. As an example, the printed image layer 3 is provided by offset inkjet printing on the surface coating layer 2. Details of these inkjet printing methods will be described later.

[0036] The can container 50 of the embodiment shown in Fig. 3 can prevent scratches on the can container 50 when the diameter of the can container 50 is reduced, and can prevent metal powder from adhering to the mold when the diameter of the can container 50 is reduced. Furthermore, the can container 50 of the embodiment shown in Fig. 3 does not repel the ink composition when printing is performed using the ink composition, and can produce an image with excellent image quality.

[0037] 4 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may have a can body 1, a surface coating layer 2, and a printed image layer 3 as its layer structure.

[0038] The reduced diameter portion 100 of the can container 50 may include a can body 1, a surface coating layer 2, and a printed image layer 3. The can body 200 of the can container 50 may include a can body 1 and a printed image layer 3.

[0039] The surface coating layer 2 may be provided on at least the reduced diameter portion 100 of the can container 50. The printed image layer 3 may be formed by printing an ink composition on all or at least a part of the outer circumferential surface of the can container 50. Unless otherwise specified, the layer structure described above may be applied as is.

[0040] The can container 50 of the embodiment shown in Fig. 4 has the minimum surface coating layer 2 required when reducing the diameter of the can container 50, and therefore can have a smaller amount of varnish. Furthermore, the can container 50 of the embodiment shown in Fig. 4 does not repel the ink composition when printing with the ink composition, and can produce an image with excellent image quality.

[0041] 5 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, a surface coating layer 2, a receiving layer 4, a printed image layer 3, and a protective layer 5.

[0042] The receiving layer 4 is a layer that enables inkjet printing on materials that are not or difficult to inkjet print on, and is a layer that receives the ink composition contained in the printed image layer 3. The surface coating layer 2, the printed image layer 3, and the receiving layer 4 may be provided on all or at least a part of the outer peripheral surface of the can container 50.

[0043] The receiving layer 4 may be a swelling-type receiving layer with a transparent surface or a whitish porous receiving layer. The swelling-type receiving layer is made of a resin that easily absorbs ink, and the absorbed ink swells the resin and remains in the swelling-type receiving layer, making it possible to print on the swelling-type receiving layer.

[0044] The base resin contained in the swelling-type receiving layer is not limited as long as it is a resin that easily absorbs ink, but may be an acrylic resin, a polyester resin, an epoxy resin, a vinyl resin, a urethane resin, or a blend of these. Of these, it is preferable to include one or more selected from acrylic resins, polyester resins, epoxy resins, urethane resins, and blends of these. When forming a blend resin, the proportion of each resin is not particularly limited, and a blend of two or more types may be used.

[0045] The swelling-type receiving layer may also contain other resins as long as the resin does not impair its function. The base resin contained in the swelling-type receiving layer is preferably in a semi-cured state, since the resin's ability to absorb ink and swell may be reduced when it is cured.

[0046] The porous receiving layer contains inorganic fine particles, which form voids inside, and ink penetrates into the voids and remains in the porous receiving layer, allowing printing onto the porous receiving layer. The inorganic fine particles contained in the porous receiving layer are not limited as long as they can form voids, but may be silica, alumina, titania (titanium oxide), boron nitride, etc. Of these, silica and alumina are preferably selected.

[0047] The particle size of the inorganic fine particles is not particularly limited, but the average primary particle size may be 10 nm or more, or 50 nm or more, or 50 μm or less. The average primary particle size of the inorganic fine particles can be calculated from the results of measuring the particle size distribution using a laser diffraction / scattering particle size distribution analyzer or the like, but for commercially available products, catalog values ​​may be used.

[0048] When the receiving layer 4 is the swelling type receiving layer or the porous type receiving layer, the ink composition may penetrate into the receiving layer 4 when printing with the ink composition. Therefore, the printed image layer 3 does not necessarily have to be laminated on the receiving layer 4 as shown in FIG.

[0049] The thickness of the receiving layer 4 is not particularly limited, but may be, for example, 0.1 μm to 50 μm. When the thickness of the receiving layer 4 is in the above range, the ink composition contained in the printed image layer 3 can be appropriately received.

[0050] The receiving layer 4 may be formed by applying a solution in which a resin component is dissolved in an organic solvent and baking the solution. The solution in which a resin component is dissolved in an organic solvent may be applied to all or at least a portion of the surface of the surface coating layer 2. The resin component may contain a thermosetting acrylic resin, a thermosetting epoxy resin, a thermosetting polyurethane resin, or a thermosetting polyester resin. Baking may be performed by heat, air, ultraviolet irradiation, or electron beam irradiation. There are no particular restrictions on the type of organic solvent that can be used.

[0051] The receiving layer 4 may further contain a white pigment. Examples of white pigments include titanium oxide, zinc sulfide, zinc oxide (zinc white), and lithopone (a mixture of zinc sulfide and barium sulfate), with titanium oxide being particularly preferred. By including a white pigment in the receiving layer 4, the image in the printed image layer 3 formed on the receiving layer 4 can be more clearly recognized.

[0052] By additionally providing the receiving layer 4 on the surface coating layer 2, the receiving layer 4 can firmly hold and fix the printed image layer 3 provided thereon, thereby increasing the adhesion between the surface coating layer 2 and the printed image layer 3. Furthermore, by providing the receiving layer 4, the can container 50 can have an image with better image quality.

[0053] The protective layer 5 is a layer that protects the printed image layer 3 from external impacts and the like. The protective layer 5 may be provided on the printed image layer 3. The protective layer 5 may be provided on the entire outer peripheral surface of the can container 50 or on at least a part of the outer peripheral surface.

[0054] The thickness of the protective layer 5 may be 0.5 μm or more and 15 μm or less. When the thickness of the protective layer 5 is in the above range, the protective layer 5 can adequately protect the printed image layer 3.

[0055] The protective layer 5 may contain a resin component. The protective layer 5 may be formed by applying a solution in which the resin component is dissolved in an organic solvent, followed by baking. The solution in which the resin component is dissolved in an organic solvent may be applied to all or at least a portion of the surface of the printed image layer 3. The resin component may contain a thermosetting acrylic resin, a thermosetting epoxy resin, or a thermosetting polyester resin. Baking may be performed by heat, air, ultraviolet irradiation, or electron beam irradiation.

[0056] By additionally providing the protective layer 5 on the printed image layer 3, the protective layer 5 protects the printed image of the printed image layer 3 from deterioration due to physical impact, oxygen, moisture, etc., thereby improving the durability of the can container 50. Furthermore, by providing the protective layer 5, color transfer of the printed image of the printed image layer 3 can be prevented. Furthermore, by providing the protective layer 5, the can container 50 can have a smooth surface.

[0057] Only one of the receiving layer 4 and the protective layer 5 may be provided on the can container 50. Alternatively, both the receiving layer 4 and the protective layer 5 may be provided on the can container 50.

[0058] The can container 50 of the embodiment shown in Fig. 5 can have an image with better image quality by being provided with the receiving layer 4. Furthermore, the can container 50 of the embodiment shown in Fig. 5 can have improved durability by being provided with the protective layer 5, which protects the printed image of the printed image layer 3.

[0059] 6 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, a base image layer 6, a surface coating layer 2, and a printed image layer 3.

[0060] The reduced diameter portion 100 of the can container 50 may include a can body 1, a base image layer 6, a surface coating layer 2, and a printed image layer 3. The can body 200 of the can container 50 may include a can body 1, a surface coating layer 2, and a printed image layer 3.

[0061] The base image layer 6 serves as a base for laminating the printed image layer 3. The base image layer 6 may be a layer formed by forming a base on the can body 1 and then printing the base using an ink composition. The base may contain an acrylic resin, an epoxy resin, a polyurethane resin, a rosin-modified phenolic resin, a polyester resin, a petroleum resin, a ketone resin, a rosin-modified maleic acid resin, an amino resin, or a benzoguanamine resin.

[0062] The base image layer 6 may be provided at least on the reduced diameter portion 100 of the can container 50. A surface coating layer 2 may be provided on the base image layer 6. After the surface coating layer 2 is provided on the base image layer 6, a printed image layer 3 may be further provided on the surface coating layer 2. The surface coating layer 2 and the printed image layer 3 may be provided on all or at least a part of the outer peripheral surface of the can container 50.

[0063] The base of the base image layer 6 may be formed by applying a solution in which a resin component is dissolved in an organic solvent and baking the solution. The solution in which a resin component is dissolved in an organic solvent may be applied to all or at least a portion of the surface of the can body 1. The resin component may contain a thermosetting acrylic resin, a thermosetting epoxy resin, a thermosetting polyester resin, or a thermosetting polyurethane resin. Baking may be performed by heat, air, ultraviolet irradiation, or electron beam irradiation.

[0064] The base image layer 6 may be formed by solid printing. The base image layer 6 may be formed by pattern printing. In the printing to form the base image layer 6, a single color ink composition such as white or transparent may be used. In the printing to form the base image layer 6, a plurality of colors of ink compositions may be used.

[0065] By additionally providing the base image layer 6 on the can body 1, the image of the printed image layer 3 becomes clearer. Furthermore, providing the base image layer 6 can enhance the decorative properties of the printed image layer 3. Furthermore, because the base image layer 6 and the printed image layer 3 are in contact with each other via the surface coating layer 2, the base image layer 6 and the printed image layer 3 are not in direct contact with each other. Therefore, the images of the base image layer 6 and the printed image layer 3 can be superimposed without mixing of the ink composition between them, thereby increasing the degree of freedom in printing on the can container 50.

[0066] The can container 50 of the embodiment shown in Fig. 6 can have a clearer image of the printed image layer 3 by providing the base image layer 6. Furthermore, the can container 50 of the embodiment shown in Fig. 6 can have improved decorating properties.

[0067] 7 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, a base image layer 6, a surface coating layer 2, and a printed image layer 3.

[0068] The reduced diameter portion 100 of the can container 50 may include a can body 1, a base image layer 6, and a surface coating layer 2. The can body 200 of the can container 50 may include a can body 1, a surface coating layer 2, and a printed image layer 3.

[0069] The base image layer 6 may be provided on at least the reduced diameter portion 100 of the can container 50. The surface coating layer 2 may be provided on all or at least a part of the outer circumferential surface of the can container 50. The printed image layer 3 may be provided on at least the can body portion 200 of the can container 50.

[0070] The embodiment of the can container 50 shown in Figure 7 has a base image layer 6 in the narrowed diameter portion 100 and a printed image layer 3 in the can body portion 200, and is therefore suitable for cases where there is no need to superimpose the image of the base image layer 6 and the image of the printed image layer 3.

[0071] 8 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, a base image layer 6, a surface coating layer 2, and a printed image layer 3. The base image layer 6, the surface coating layer 2, and the printed image layer 3 may be provided on all or at least a part of the outer peripheral surface of the can container 50.

[0072] The embodiment of the can container 50 shown in Figure 8 has a base image layer 6 and a printed image layer 3 formed over the narrowed diameter portion 100 and the can body portion 200, making it suitable for cases where an image is to be formed widely over the outer peripheral surface of the can container 50.

[0073] 9 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, a base image layer 6, a surface coating layer 2, and a printed image layer 3.

[0074] The reduced diameter portion 100 of the can container 50 may include a can body 1, a base image layer 6, a surface coating layer 2, and a printed image layer 3. The can body 200 of the can container 50 may include the can body 1 and the printed image layer 3.

[0075] The base image layer 6 may be provided at least on the narrowed diameter portion 100 of the can container 50. The surface coating layer 2 may be provided at least on the narrowed diameter portion 100 of the can container 50. The printed image layer 3 may be provided on all or at least a part of the outer peripheral surface of the can container 50.

[0076] The can container 50 of the embodiment shown in Fig. 9 can have a smaller amount of varnish. Also, the can container 50 of the embodiment shown in Fig. 9 can have improved decorative properties because the images of the base image layer 6 and the printed image layer 3 can be superimposed in the reduced diameter portion 100.

[0077] 10 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, an ink-repellent varnish layer 7, a surface coating layer 2, and a printed image layer 3. The ink-repellent varnish layer 7 serves to improve the slipperiness of the can container 50 when forming the reduced diameter portion 100 in the can container 50.

[0078] The reduced diameter portion 100 of the can container 50 may include a can body 1 and an ink-repellent varnish layer 7. The can body 200 of the can container 50 may include a can body 1, a surface coating layer 2, and a printed image layer 3.

[0079] The ink-repellent varnish layer 7 may be provided at least on the narrowed diameter portion 100 of the can container 50. The surface coating layer 2 and the printed image layer 3 may be provided at least on the can body portion 200 of the can container 50. If the ink-repellent varnish layer 7 has ink-repellent properties, the printed image layer 3 does not need to be provided directly on the ink-repellent varnish layer 7.

[0080] The ink-repellent varnish contained in the ink-repellent varnish layer 7 may contain at least a resin component. The ink-repellent varnish may contain at least a wax component. The ink-repellent varnish may contain both a resin component and a wax component. The ink-repellent varnish may contain, as a resin component, a thermosetting acrylic resin, a thermosetting epoxy resin, or a thermosetting polyester resin, but is not limited to these. The ink-repellent varnish may contain, as a wax component, an olefin hydrocarbon, a paraffin hydrocarbon, oils and fats, a synthetic polymer resin, or an organic fluorine compound, but is not limited to these.

[0081] The ink-repellent varnish contained in the ink-repellent varnish layer 7 may contain a leveling agent. For example, the ink-repellent varnish contained in the ink-repellent varnish layer 7 may contain an antifoaming agent, an anti-cising agent, a fluorine-based compound, a silicon-based compound, etc.

[0082] The ink-repellent varnish contained in the ink-repellent varnish layer 7 contains a leveling agent, so that the surface free energy of the ink-repellent varnish layer 7 calculated from the Kaelble-Uy equation based on the contact angle measured in accordance with JIS R 3257:1999 is 20 mJ / m at a temperature of 25°C. 2The thickness of the ink-repellent varnish layer 7 may be 0.5 μm or more and 15 μm or less. When the surface free energy and thickness of the ink-repellent varnish layer 7 are within the above ranges, smoothness can be ensured when forming the reduced diameter portion 100 on the can container 50.

[0083] The ink-repellent varnish layer 7 may be formed by applying and baking an ink-repellent varnish to the outer peripheral surface of the can body 1. The ink-repellent varnish may be applied to all or at least a portion of the outer peripheral surface of the can body 1. Baking may be performed by heat, air, ultraviolet irradiation, or electron beam irradiation.

[0084] Although ink-repellent varnish is not suitable for forming the printed image layer 3, it can provide good slip properties to the can container 50. Therefore, by additionally providing the ink-repellent varnish layer 7 on the can body 1, it is possible to prevent the can container 50 from being scratched when forming the reduced diameter portion 100 in the can container 50 and to prevent metal powder from adhering to the mold when reducing the diameter of the can container 50.

[0085] 10 can prevent scratches on the can container 50 when the diameter of the can container 50 is reduced, and prevent metal powder from adhering to the mold when the diameter of the can container 50 is reduced. In addition, the can container 50 of the embodiment shown in FIG. 10 is suitable for cases where it is not necessary to form a printed image layer 3 on the reduced diameter portion 100.

[0086] 11 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, an ink-repellent varnish layer 7, a surface coating layer 2, and a printed image layer 3.

[0087] The reduced diameter portion 100 of the can container 50 may include a can body 1 and an ink-repellent varnish layer 7. The can body 200 of the can container 50 may include a can body 1, an ink-repellent varnish layer 7, a surface coating layer 2, and a printed image layer 3.

[0088] The ink-repellent varnish layer 7 may be provided on all or at least a portion of the outer peripheral surface of the can container 50. The surface coating layer 2 and the printed image layer 3 may be formed on at least the can body 200 of the can container 50.

[0089] The can container 50 of the embodiment shown in Figure 11 is provided with an ink-repellent varnish layer 7 and a surface coating layer 2, and is therefore suitable for cases where it is desired to form a printed image layer 3 on top of the ink-repellent varnish layer 7.

[0090] 12 shows another example of the overall layer structure of a can container 50 in this embodiment. The can container 50 may include a can body 1, a surface coating layer 2, an additional varnish layer 8, and a printed image layer 3. The additional varnish layer 8 is a layer containing varnish formed on the surface coating layer 2 when the surface coating layer 2 is a resin film.

[0091] An additional varnish layer 8 may be provided on all or at least a part of the surface of the surface coating layer 2. For example, the additional varnish layer 8 may be provided only on the narrowed diameter portion 100 of the can container 50. In addition, a printed image layer 3 may be provided on at least one of the surface coating layer 2 and the additional varnish layer 8.

[0092] The varnish contained in the additional varnish layer 8 may be of the same ingredients as the varnish contained in the surface coating layer 2 when it contains varnish. For example, the varnish contained in the additional varnish layer 8 may contain a lubricant. When the varnish contained in the additional varnish layer 8 is of the same ingredients as the varnish contained in the surface coating layer 2, the ink composition is not repelled when printing using the ink composition on the additional varnish layer 8, and an image with excellent image quality can be obtained.

[0093] 12 has the effect of providing excellent adhesion between the can body 1 and the additional varnish layer 8 or printed image layer 3 provided on the surface coating layer 2 due to the softness and flexibility of the resin of the surface coating layer 2. Furthermore, by providing the additional varnish layer 8 on at least the reduced diameter portion 100 of the can container 50, it is possible to prevent the can container 50 from being scratched when the reduced diameter portion 100 is formed on the can container 50.

[0094] Fig. 13 shows an example of a flow for manufacturing the can container 50 of this embodiment. The can container 50 of this embodiment can be manufactured by performing the processes of S10 to S95 in Fig. 13. For convenience of explanation, the processes of S10 to S95 will be explained in order, but at least some of these processes may be performed in parallel, or the steps may be interchanged within the scope of the present invention.

[0095] First, in S10, a metal coil material is wet-formed. In the wet-forming, the metal coil material is punched into a cup shape, and the side wall is stretched to form the can body 200. In S10, the wet-forming includes steps S11 to S16, as shown in FIG.

[0096] FIG. 14 is a diagram showing S10 in the flow.

[0097] First, in S11, an uncoiler step is performed to unwind and stretch a coiled metal coil material, which may be, but is not limited to, aluminum or steel.

[0098] Next, in S12, a lubricator step is performed to apply a lubricant to the metal material. The lubricant may be a lubricant. Any known lubricant may be used.

[0099] Next, in S13, a cupping press step is performed in which the metal material is punched into a cup shape to form a cup-shaped material.

[0100] Next, in S14, the cup-shaped blank is subjected to a drawing process using a coolant to thin the can body and form the bottom, which is called the bodymaker step. The coolant may be a lubricant. Known lubricants can be used.

[0101] Next, in S15, a trimmer step is performed on the cup-shaped material to cut off unnecessary portions and make the height uniform.

[0102] Next, in S16, a washer step is performed in which the cup-shaped material is washed and dried, and the applied coolant and the like are removed. The washed and dried cup-shaped material is referred to as a can body 1. The can body 1 proceeds to step S20.

[0103] Next, in S20, varnish is applied to at least a portion of the outer circumferential surface of the can body 1. The varnish may contain at least a resin component. The varnish may contain at least a wax component. The varnish may contain both a resin component and a wax component. The varnish may not contain a leveling agent.

[0104] The resin component may include, but is not limited to, a thermosetting acrylic resin, a thermosetting epoxy resin, or a thermosetting polyester resin. The wax component may include, but is not limited to, an olefin hydrocarbon, a paraffin hydrocarbon, oils and fats, a synthetic polymer resin, or an organic fluorine compound. The varnish can be applied to the can body 1 by a known method. The can body 1 to which the varnish has been applied is referred to as a can container 50.

[0105] Next, in S30, the can container 50 is baked to form the surface coating layer 2. Baking can be performed by a known method. For example, baking may be performed by hot air drying. As an example, baking can be performed under conditions of a heating temperature of 170 to 215°C for about 0.5 to 3 minutes.

[0106] Since the varnish does not contain a leveling agent, the surface free energy of the surface coating layer 2 at a temperature of 25°C calculated from the Kaelble-Uy equation based on the contact angle measured in accordance with JIS R 3257:1999 is 30 mJ / m 2 More than 50mJ / m 2Since the varnish does not contain a leveling agent, the coefficient of dynamic friction of the surface of the surface coating layer 2, measured in accordance with JIS K 7125:1999, may be 0.30 or less. The thickness of the surface coating layer 2 may be 0.5 μm or more and 15 μm or less.

[0107] Next, in S40, paint is applied to the inner peripheral surface of the can container 50 and baked. Coating the inner peripheral surface of the can container 50 with paint makes the inner peripheral surface less susceptible to scratches. Any known paint may be used. The paint may be applied by spray painting. Baking may be performed by a known method. For example, baking may be performed by hot air drying.

[0108] Next, in S50, necking is performed on the can container 50 to form the reduced diameter portion 100. The necking can be performed by a known method. For example, the necking may be performed by the method described in Japanese Patent Publication No. 2748856 or Japanese Patent Publication No. 2705571.

[0109] For example, necking may be performed to reduce the diameter of at least a portion of the can container 50 where the surface coating layer 2 is formed, thereby forming a reduced diameter portion 100. In this case, the surface coating layer 2 is provided at least in the reduced diameter portion 100. For example, necking may be performed to reduce the diameter of at least a portion of the can container 50 where the base image layer 6 is formed, thereby forming the reduced diameter portion 100. In this case, the base image layer 6 is provided at least in the reduced diameter portion 100. For example, necking may be performed to reduce the diameter of at least a portion of the can container 50 where the ink-repellent varnish layer 7 is formed, thereby forming the reduced diameter portion 100. In this case, the ink-repellent varnish layer 7 is provided at least in the reduced diameter portion 100.

[0110] After necking, the can container 50 may be subjected to flange processing to form a flange for attaching a can lid. After necking, the can container 50 proceeds to step S60.

[0111] Next, in S60, an ink composition is printed onto all or at least a portion of the outer circumferential surface of the can container 50 (for example, the reduced diameter portion 100 or the can body portion 200). The printing may be performed on the surface coating layer 2. The printing may be performed by inkjet printing. The printing may be performed by plate-type offset printing. As an example, the inkjet printing may be performed by the method described in Japanese Patent Publication No. 6314468.

[0112] Inkjet printing may be a method of directly ejecting an ink composition from an inkjet head provided in an inkjet printer onto a can container. As an example, inkjet printing may be a direct inkjet printing method in which an ink composition is directly ejected from an inkjet head provided in an inkjet printer onto a can container 50. As an example, inkjet printing may be an offset inkjet printing method in which an ink composition is ejected from an inkjet head provided in an inkjet printer onto a blanket, and an inkjet image formed on the blanket is transferred to the can container 50.

[0113] The ink composition used for printing may be, but is not limited to, an aqueous ink, a solvent ink, an ultraviolet-curable ink, or an electron beam-curable ink. The image formed by printing may be a color image using ink compositions of multiple colors. The image formed by printing may be a monochrome image using an ink composition of one color.

[0114] When printing the ink composition on a can 50, the can 50 may be fixed to a can holder and then the ink composition may be printed. A known can holder, such as a star wheel, may be used as the can holder. For example, the can 50 may be fixed by the method described in Japanese Patent Publication No. 6124024. For example, the can 50 may be fixed to the can holder by chucking the bottom of the can 50. As an example, the can 50 may be fixed to the can holder by vacuum suction.

[0115] In order to stably fix the can container 50, a pressing member may be provided in addition to the can container holding member. By providing a pressing member, the can container 50 can be fixed even more stably. Furthermore, by providing a pressing member, the ink composition can be prevented from entering the inside of the can container 50. The pressing member may be disposed in a position where it presses the reduced diameter portion 100 or the opening of the can container 50. The pressing member may or may not cover the reduced diameter portion 100.

[0116] If the ink composition or varnish is highly irritating or sensitizing to the skin, by placing a pressing member to cover the reduced diameter portion 100, the ink composition or varnish can be prevented from being applied to the reduced diameter portion 100, thereby reducing the irritation and sensitization to the skin.

[0117] Next, in S70, the printed can container 50 is baked to form a printed image layer 3. By baking, the printed image is fixed to the can container 50. Baking may be performed by heat drying, and air drying may be performed by ultraviolet irradiation, electron beam irradiation, or the like. The can container 50 on which the printed image layer 3 has been formed proceeds to step S80.

[0118] Next, in S80, the can container 50 on which the printed image layer 3 is formed is inspected. For example, the inspection may be to check whether there are any dents or holes on the outer or inner surface of the can container 50. For example, the inspection may be to check whether the printed image of the printed image layer 3 is clear.

[0119] Next, in S90, the contents are filled into the inspected can container 50. For example, the filling of the contents may be carried out by filling a certain amount of the contents with a filler (filling machine), but is not limited to this.

[0120] Next, in S95, a can lid is attached to the filled can container 50. For example, the can lid may be attached by using a lid seaming machine to cover the opening of the can container 50 and then seaming the lid around the can container 50, but this is not limitative. In this manner, the can container 50 shown in the embodiment of FIGS. 3 and 4 can be obtained.

[0121] Steps S10 to S50 may be performed at a can manufacturing plant. Steps S60 to S95 may be performed at a bottler. When steps S60 and after are performed at a bottler, the can manufacturing plant performs steps S10 to S50 and stores the can containers 50 on which the printed image layer 3 is not formed.

[0122] In this case, even if the printed image on the printed image layer 3 is changed, the bottler can print the changed image on the can containers 50, thereby reducing the number of can containers 50 to be discarded. Furthermore, the design of the printed image can be changed more swiftly and with greater flexibility. Furthermore, since there is no need to store many different types of printed can containers 50 at the can manufacturing factory, this method is advantageous in terms of storage costs and can meet the needs of small-lot production of a wide variety of products.

[0123] Steps S10 to S70 may be performed at a can factory and steps S80 to S95 may be performed at a bottler. Steps S10 to S80 may be performed at a can factory and steps S90 and S95 may be performed at a bottler, but this is not a limitation.

[0124] Next, modified examples of this embodiment will be described. A can container may be manufactured by combining a plurality of the modified examples shown below. [First Modification] In this embodiment, a flow for manufacturing the can container 50 by wet molding is shown. In the first modified example, a flow for manufacturing the can container 50 by dry molding is shown. In the can container 50 manufactured by the first modified example, the surface coating layer 2 is in a film-like form.

[0125] Fig. 15 shows an example of a flow for manufacturing a can container 50 by dry molding. The can container 50 of the first modified example can be manufactured by performing the processes of S110 to S95 in Fig. 15. For convenience of explanation, the processes of S110 to S95 will be explained in order, but at least some of these processes may be performed in parallel, or the steps may be interchanged within the scope of the present invention.

[0126] First, in S110, dry forming is performed on a metal coil material. In dry forming, a resin film is coated on the metal coil material, punched into a cup shape, and the side wall is stretched to form a can body. In S110, dry forming includes steps S11 to S15 as shown in FIG. 16.

[0127] FIG. 16 is a diagram showing S110 in the flow.

[0128] First, in S11, an uncoiler step is performed to unwind and stretch a coiled metal coil material, which may be, but is not limited to, aluminum or steel.

[0129] Next, in S120, a resin film is laminated on one or both sides of the metal. For example, the laminator described in JP 2004-25640 A may be used to laminate the resin film. The can body 1 laminated with the resin film is referred to as a can container 50. After S120 is completed, the process may proceed to step S13. Note that, before proceeding to step S13, a lubricant may be applied to the metal laminated with the resin film, if necessary. Steps S13 to S15 may be the same as the wet molding steps in FIG. 14.

[0130] After the dry molding of S110, the can container 50 may be subjected to step S50. When the surface coating layer 2 is formed in step S110, the metal coil material is coated with a resin film, thereby improving the slipperiness of the can container 50 and preventing the surface from being scratched during processing of the can container 50, even without applying varnish. In addition, since the reduced diameter portion 100 can be formed without applying varnish, the step of washing away the varnish after necking (e.g., step S16 in wet molding) can be omitted, thereby reducing water consumption. By performing the flow of FIG. 15, the can container 50 shown in the embodiment of FIG. 3 can be obtained.

[0131] [Second Modification] In this embodiment, the surface coating layer 2 is formed on all or at least a part of the outer peripheral surface of the can body 1. In the second modified example, a base image layer 6 is formed on all or at least a part of the outer peripheral surface of the can body 1, and then the surface coating layer 2 is formed.

[0132] FIG. 17 shows a step of forming a base image layer 6 on all or at least a part of the outer peripheral surface of the can body 1 after performing S16 and before proceeding to step S20.

[0133] In S171, a solution in which a resin component is dissolved in an organic solvent may be applied to all or at least a portion of the outer circumferential surface of the can body 1 that has been wet-molded. The resin component may include a thermosetting acrylic resin, a thermosetting epoxy resin, or a thermosetting polyurethane resin. The solution in which a resin component is dissolved in an organic solvent may be formed on the surface of at least the portion of the can body 1 that will be reduced in diameter. The applied resin component is baked to form a base. Baking can be performed by a known method.

[0134] Next, in S172, printing is performed on the substrate using the ink composition. The printing may be solid printing or pattern printing. The pattern may be a stripe pattern or a gradient pattern. The printing color may be colorless and transparent or white. The printing color may be a single color other than white, or multiple colors.

[0135] Next, in S173, the printed ink composition is baked to form a base image layer 6. Baking can be performed by a known method. The can body 1 on which the base image layer 6 has been formed is referred to as a can container 50.

[0136] By additionally performing steps S171 to S173, a can container 50 can be obtained in which the base image layer 6 is formed only in the narrowed portion 100, as shown in the embodiments of Figures 6, 7, and 9. Furthermore, by additionally performing steps S171 to S173, a can container 50 can be obtained in which the base image layer 6 is formed in the narrowed portion 100 and the can body portion 200, as shown in the embodiment of Figure 8. These can containers 50 are then subjected to step S20. In S20, a varnish for forming the surface coating layer 2 may be applied on the base image layer 6.

[0137] In the first modified example, the base image layer 6 may be formed by the above method on the can body 1 that has been dry-molded in S110 before proceeding to step S50. In this case, the can body 1 (i.e., the can container 50) on which the base image layer 6 has been formed may proceed to step S50.

[0138] [Third Modification] In this embodiment, the surface coating layer 2 is formed on all or at least a portion of the outer peripheral surface of the can body 1. In the third modified example, an ink-repellent varnish layer 7 is formed on all or at least a portion of the outer peripheral surface of the can body 1, and then the surface coating layer 2 is formed.

[0139] FIG. 18 shows a step of forming an ink-repellent varnish layer 7 on all or at least a part of the outer circumferential surface of the can body 1 that has been subjected to S16, before proceeding to S20.

[0140] In S181, an ink-repellent varnish containing a resin component and a wax component may be applied to the outer peripheral surface of at least the portion of the can body 1 where the diameter is reduced.

[0141] Next, in S182, the ink-repellent varnish layer 7 may be formed on the can body 1 by heating, drying, and irradiating with ultraviolet light or electron beams. When the ink-repellent varnish contains a leveling agent, the surface free energy of the ink-repellent varnish layer 7 calculated from the Kaelble-Uy equation based on the contact angle measured in accordance with JIS R 3257:1999 is 20 mJ / m at a temperature of 25°C. 2 It may be the following:

[0142] The ink-repellent varnish may be a commercially available varnish. The ink-repellent varnish may contain, but is not limited to, a thermosetting acrylic resin, a thermosetting epoxy resin, or a thermosetting polyester resin as a resin component. The wax may contain, but is not limited to, an olefin hydrocarbon, a paraffin hydrocarbon, oils and fats, a synthetic polymer resin, or an organic fluorine compound. The ink-repellent varnish may contain a leveling agent. The can body 1 on which the ink-repellent varnish layer is formed is referred to as a can container 50.

[0143] By additionally performing steps S181 and S182, a can container 50 can be obtained in which the ink-repellent varnish layer 7 is formed only on the narrowed diameter portion 100, as shown in the embodiment of Figure 10. Furthermore, by additionally performing steps S181 and S182, a can container 50 can be obtained in which the ink-repellent varnish layer 7 is formed on the narrowed diameter portion 100 and the can body portion 200, as shown in the embodiment of Figure 11. These can containers are then subjected to step S20. In S20, a varnish for forming the surface coating layer 2 may be applied onto the ink-repellent varnish layer 7.

[0144] [Fourth Modification] In the embodiment of the first modified example, the can body 1 is manufactured by dry molding, and a surface coating layer 2 in a film-like form is formed on the outer peripheral surface of the can body 1. In the fourth modified example, an additional varnish layer 8 is further formed on all or at least a part of the surface coating layer 2 in a film-like form.

[0145] FIG. 19 shows a step of forming an additional varnish layer 8 by applying varnish to all or at least a part of the outer peripheral surface of the can body 1 that has been subjected to S15 of the dry forming in S110, before proceeding to S20.

[0146] In S191, a varnish containing a resin component and a wax component may be applied to at least the outer peripheral surface of the portion of the can body 1 that is to be reduced in diameter. The varnish may have the same components as the varnish contained in the surface coating layer 2.

[0147] Next, in S192, baking may be performed by heating, drying, ultraviolet irradiation, electron beam irradiation, or the like to form an additional varnish layer 8 on the can body 1. The can body 1 on which the additional varnish layer 8 has been formed is referred to as a can container 50.

[0148] By additionally performing steps S191 and S192, a can container 50 can be obtained in which an additional varnish layer 8 is formed on the reduced diameter portion 100 and the can body portion 200, as shown in the embodiment of Figure 12. This can container 50 is then subjected to step S50.

[0149] [Fifth Modification] In this embodiment, the printed image layer 3 is formed on all or at least a part of the surface coating layer 2 of the can container 50. In the fifth modified example, a receiving layer 4 is formed on all or at least a part of the surface coating layer 2, and then the printed image layer 3 is formed.

[0150] 20 shows a step of forming a receiving layer 4 on all or at least a part of the outer peripheral surface of the can container 50 on which the reduced diameter portion 100 has been formed in S50, before proceeding to step S60. The receiving layer 4 may be formed on at least the reduced diameter portion 100 of the can container 50. The receiving layer 4 may be formed on at least the surface coating layer 2 of the can container 50.

[0151] In S51, a solution in which a resin component is dissolved in an organic solvent is applied to the entire surface of the surface coating layer 2 of the can container 50 or at least a part of the surface of the surface coating layer 2.

[0152] Next, in S52, the can container 50 coated with the solution of a resin component dissolved in an organic solvent may be baked to form the receiving layer 4. The resin component may include a thermosetting acrylic resin, a thermosetting epoxy resin, a thermosetting polyurethane resin, or a thermosetting polyester resin. The thickness of the receiving layer 4 may be 0.1 μm or more and 50 μm or less. Baking may be performed using heat, air, ultraviolet light, electron beam irradiation, or the like.

[0153] By additionally performing steps S51 and S52, a can container 50 can be obtained in which a receiving layer 4 is formed on the reduced diameter portion 100 and the can body portion 200, as shown in the embodiment of Figure 5. The can container 50 on which the receiving layer 4 has been formed then proceeds to step S60.

[0154] [Sixth Modification] In this embodiment, an ink composition is printed on a can container 50 on which a surface coating layer 2 is formed to form a printed image layer 3. In the sixth modified example, before printing the ink composition on the surface coating layer 2, at least a portion of the wax component contained in the surface coating layer 2 is evaporated.

[0155] FIG. 21 shows step S55, in which the can container 50 having the reduced diameter portion 100 formed therein in S50 is heated to evaporate at least a part of the wax component contained in the surface coating layer 2, before proceeding to step S60.

[0156] In S55, the heat treatment may be carried out at 170 to 215°C for 0.5 to 10 minutes. Since the varnish does not contain a leveling agent, the surface free energy of the surface of the can container 50 after at least a part of the wax component has evaporated is calculated from the Kaelble-Uy equation based on the contact angle measured in accordance with JIS R 3257:1999 and is 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 The following may be true: By evaporating the wax component, it is possible to prevent ink from being repelled when printing is performed on the surface coating layer 2. The can container 50 from which at least a portion of the wax component has evaporated proceeds to step S60.

[0157] In addition, in the fourth variant, if an additional varnish layer 8 is formed on all or at least part of the surface coating layer 2, a process similar to that described above may be carried out to evaporate at least part of the wax components contained in the additional varnish layer 8.

[0158] [Seventh Modification] In this embodiment, an ink composition is printed on a can container 50 on which a surface coating layer 2 is formed to form a printed image layer 3. In the seventh modification, before printing the ink composition on the surface coating layer 2, at least a portion of the wax component contained in the surface coating layer 2 is removed by washing.

[0159] FIG. 22 shows step S56 in which the can container 50 having the reduced diameter portion 100 formed thereon in step S50 is washed to remove at least a part of the wax component contained in the surface coating layer 2, before proceeding to step S60.

[0160] In S56, the cleaning may be performed by rinsing with water. Since the varnish does not contain a leveling agent, the surface free energy of the surface of the can container 50 after at least a part of the wax component has been removed is calculated from the Kaelble-Uy equation based on the contact angle measured in accordance with JIS R 3257:1999 and is 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2The following may be true: By removing the wax component, it is possible to prevent ink from being repelled when printing is performed on the surface coating layer 2. The can container 50 from which at least a portion of the wax component has been removed proceeds to step S60.

[0161] In addition, in the fourth variant, if an additional varnish layer 8 is formed on all or at least part of the surface coating layer 2, the same process as described above may be performed to remove at least part of the wax components contained in the additional varnish layer 8 by washing.

[0162] [Eighth Modification] In this embodiment, the printed image layer 3 is formed on the can container 50. In the eighth modification, a protective layer 5 is further formed on the entire or at least a part of the printed image layer 3 of the can container 50.

[0163] FIG. 23 shows a step of forming a protective layer 5 containing a resin component on the can container 50 on which the print image layer 3 has been formed, before proceeding to step S80.

[0164] In S71, a solution in which a resin component is dissolved in an organic solvent is applied to all or at least a part of the surface of the printed image layer 3. The resin component may include a thermosetting acrylic resin, a thermosetting epoxy resin, or a thermosetting polyester resin.

[0165] Next, in S72, the can container 50 coated with the solution prepared by dissolving a resin component in an organic solvent may be baked to form a protective layer 5 on the can container 50. Baking may be performed by heat, wind, ultraviolet irradiation, electron beam irradiation, or the like. The thickness of the protective layer 5 may be 0.5 μm or more and 15 μm or less.

[0166] By additionally performing steps S71 and S72, a can container 50 can be obtained in which a protective layer 5 is formed on the reduced diameter portion 100 and the can body portion 200, as shown in the embodiment of Figure 5. The can container 50 on which the protective layer 5 has been formed then proceeds to step S80.

[0167] [Ninth Variation] In this embodiment, an ink composition is printed on a can container 50 having a reduced diameter portion 100 formed therein to form a printed image layer 3, and then the can container 50 is filled with contents. In the ninth modification, a can container 50 having a reduced diameter portion 100 formed therein is filled with contents, and then the ink composition is printed to form a printed image layer 3. In other words, unlike this embodiment, in the ninth modification, the can container 50 is first filled with contents, and then the ink composition is printed on the can container 50.

[0168] Figure 24 shows an example of a step in which, in the ninth variant, that is, step S50 of the present embodiment in Figure 13 or step S50 of the first variant in Figure 15, after forming a reduced diameter portion 100 in the can container 50, the can container 50 is filled with contents, and then an ink composition is printed on the can container 50.

[0169] First, in S590, the contents are filled into the can container 50. For example, the filling of the contents may be carried out by filling a certain amount of the contents using a filler (filling machine), but is not limited to this.

[0170] Next, in S592, a can lid is attached to the can container 50. For example, the can lid may be attached by placing a lid on the opening of the can container 50 using a lid winding machine and winding the lid around the can container 50, but this is not limited to this.

[0171] Next, in S594, the can container 50 with the can lid attached is washed to remove wax components. Washing may be performed in the same manner as in S56, and may be, for example, washing with water. Removing the wax components by washing can prevent ink from being repelled when printing is performed on the surface coating layer 2. Note that step S594 may be omitted, or instead of washing, the wax components may be removed by heating the can container 50 in a step similar to S55 (for example, retort sterilization by heating at 125°C for 30 minutes, or pasteurization by heating at 65°C for 10 minutes).

[0172] Next, in S596, the ink composition is printed on the can 50. Step S596 may be performed in the same manner as S60. Thereafter, steps S70 and S80 are performed on the can 50 on which the ink composition has been printed. By performing these steps, the can 50 shown in the embodiment of FIGS. 3 and 4 can also be obtained. Note that after S70, steps S71 and S72 may be additionally performed to form a protective layer 5 on the can 50.

[0173] The can container 50 of the ninth variant is convenient because it is filled with the contents and then printed with an ink composition to form the printed image layer 3, allowing for flexible changes to the pattern or design to be formed on the printed image layer 3 even after the contents have been filled, thereby increasing mobility. [Example]

[0174] Specifically, the surface free energy E (mJ / m 2 The following shows the results of an experiment to confirm the relationship between the surface coating layer 2 and the image quality of the printed image. A can container 50 was prepared by performing steps S10 to S50. The can container 50 had a surface coating layer 2 and a printed image layer 3 formed on the entire outer surface, and the base image layer 6, the receiving layer 4, the ink-repellent varnish layer 7, and the additional varnish layer 8 were not formed on the outer surface. The surface free energy E of the surface coating layer 2 was measured for each of the can containers of Examples 1 to 5 and Comparative Examples 1 to 5. The surface free energy E was measured at 25°C using a contact angle meter (DropMaster DM500, manufactured by Kyowa Interface Science Co., Ltd.) in accordance with JIS R 3257:1999. The dynamic friction coefficient was measured using a heated friction coefficient measuring instrument AB-550-TS (manufactured by Tester Sangyo Co., Ltd.) in accordance with JIS K 7125:1999.

[0175] Using water and methylene iodide (diiodomethane) as liquids with known surface free energies, a contact angle meter was used to measure the contact angle on the surface of the surface coating layer 2 of the can container 50. From the measured contact angle, the surface free energy E on the surface of the surface coating layer 2 of the can container 50 was calculated using the Kaelble-Uy equation.

[0176] Next, a printed image layer 3 was formed on the surface of the surface coating layer 2 of the can container 50 by inkjet printing. The inkjet printing was performed using a head manufactured by Kyocera Corporation. The ink composition printed by inkjet printing was baked by hot air drying. The image quality of the printed image of the printed image layer 3 was evaluated visually.

[0177] [Evaluation criteria for print image quality] ○: The printed image was very clear. △: The outline of the printed image was slightly unclear, but the printed image was sufficiently recognizable. ×: The printed image was unclear.

[0178] [Evaluation criteria for can container diameter reduction molding] ○: Easily molded. ×: The can body buckled during molding, and a can container could not be manufactured.

[0179] [Table 1]

[0180] As shown in the results in Table 1, the surface free energy E of the surface of the surface coating layer 2 of the can container 50 is 30 mJ / m 2 Above 50mJ / m 2 By keeping the values ​​within the following ranges, the inkjet printed image was clear, and a can container 50 having a printed portion 300 with excellent image quality could be provided.

[0181] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0182] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the can bodies, can containers, and methods shown in the claims, specification, and drawings is not specifically stated as "before," "prior to," etc., and can be realized in any order unless the can bodies or can containers from a previous process are used in a later process. Even if the operational flow in the claims, specification, and drawings is described using "first," "next," etc. for convenience, it does not mean that it is necessary to perform the process in this order.

[0183] [Item 1] The container includes a cylindrical can body and at least a surface coating layer, the surface coating layer is formed on at least a part of the outer peripheral surface of the can body, the surface coating layer contains a resin component, The surface free energy of the surface of the surface coating layer is 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 Below is a can container. [Item 2] The dynamic friction coefficient of the surface of the surface coating layer is 0.30 or less. A can container as described in item 1. [Item 3] 3. The can container according to item 1 or 2, wherein the thickness of the surface coating layer is 0.5 μm or more and 15 μm or less. [Item 4] The can body has a reduced diameter portion whose one end is reduced in diameter and a can body portion, The surface coating layer is provided at least on the reduced diameter portion. A can container according to any one of items 1 to 3. [Item 5] Further comprising a printed image layer formed on the surface coating layer. A can container according to any one of items 1 to 4. [Item 6] a receiving layer formed on the surface coating layer; a printed image layer formed on the receiving layer, A can container according to any one of items 1 to 4. [Item 7] A protective layer containing a resin component is formed on the printed image layer. A can container according to item 5 or 6. [Item 8] The can body includes a reduced diameter portion having one end reduced in diameter, a can body portion, a base image layer formed on at least the reduced diameter portion, the surface coating layer is provided on at least the base image layer; A can container according to any one of items 1 to 7. [Item 9] The can body has a reduced diameter portion whose one end is reduced in diameter and a can body portion, an ink-repellent varnish layer containing a resin component and a wax component is formed at least on the reduced diameter portion; The surface free energy of the ink-repellent varnish layer is 20 mJ / m at a temperature of 25°C. 2 Below is the A can container according to any one of items 1 to 8. [Item 10] A method for manufacturing a can container having a cylindrical can body and at least a surface coating layer, A varnish containing a resin component and a wax component is applied to at least a part of the outer circumferential surface of the can body, Alternatively, at least a part of the outer peripheral surface of the can body is covered with a resin film, Surface free energy at 25°C is 30mJ / m 2 More than 50mJ / m 2 forming the surface coating layer, reducing the diameter of at least a portion of the can container where the surface coating layer is formed; A method for manufacturing a can container comprising the steps of: [Item 11] A method for manufacturing a can container having a cylindrical can body and at least a surface coating layer, A varnish containing a resin component and a wax component is applied to at least a part of the outer circumferential surface of the can body, Alternatively, at least a part of the outer peripheral surface of the can body is covered with a resin film, Surface free energy at 25°C is 30mJ / m 2 More than 50mJ / m 2 forming the surface coating layer, reducing the diameter of at least a portion of the can container where the surface coating layer is formed; printing an ink composition to form a printed image layer; A method for manufacturing a can container comprising the steps of: [Item 12] Item 12. The method for manufacturing a can container according to Item 11, wherein the step of forming the printed image layer is performed by inkjet printing. [Item 13] The dynamic friction coefficient of the surface of the surface coating layer is 0.30 or less. 13. The method for producing a can container according to any one of items 10 to 12. [Item 14] Item 14. The method for producing a can container according to any one of items 10 to 13, wherein the thickness of the surface coating layer is 0.5 μm or more and 15 μm or less. [Item 15] The can body has a reduced diameter portion whose one end is reduced in diameter and a can body portion, The surface coating layer is provided at least on the reduced diameter portion. 15. A method for producing a can container according to any one of items 10 to 14. [Item 16] The step of forming the print image layer includes: forming a receiving layer on the surface coating layer at least in the portion of the surface coating layer that has been reduced in diameter by the reducing step; printing an ink composition onto the receiving layer to form a printed image layer; 16. The method for producing a can container according to item 11 or any one of items 12 to 15 indirectly dependent on item 11, [Item 17] forming a protective layer containing a resin component on the printed image layer; Item 11 or any one of items 12 to 16 indirectly dependent on item 11, further comprising: [Item 18] A method for manufacturing a can container further comprising a step of forming a base image layer on at least a reduced diameter portion, the can body has the reduced diameter portion, one end of which is reduced in diameter, and a can body portion, the surface coating layer is provided on at least the base image layer; Item 18. A method for producing a can container according to any one of items 10 to 17. [Item 19] A method for manufacturing a can container, further comprising a step of forming an ink-repellent varnish layer containing a resin component and a wax component on at least the reduced diameter portion, the can body has the reduced diameter portion, one end of which is reduced in diameter, and a can body portion, The surface free energy of the ink-repellent varnish layer is 20 mJ / m at a temperature of 25°C. 2 Below is the 19. A method for producing a can container according to any one of items 10 to 18. [Item 20] A method for manufacturing a can container having a cylindrical can body, A surface coating layer is formed by applying a varnish containing a wax component to at least a part of the outer circumferential surface of the can body, or Alternatively, a step of forming a surface coating layer by coating at least a portion of the outer circumferential surface of the can body with a resin film, and then applying a varnish containing a wax component to form an additional varnish layer; reducing the diameter of at least a portion of the can container where the surface coating layer is formed; a step of heating the can container to evaporate at least a portion of the wax component contained in the surface coating layer or the additional varnish layer; A method for manufacturing a can container comprising the steps of: [Item 21] The surface free energy of the can container after the step of evaporating at least a portion of the wax component is 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 Below is the Item 20. A method for producing a can container according to item 20. [Item 22] A method for manufacturing a can container having a cylindrical can body, A surface coating layer is formed by applying a varnish containing a wax component to at least a part of the outer circumferential surface of the can body, or Alternatively, a step of forming a surface coating layer by coating at least a portion of the outer circumferential surface of the can body with a resin film, and then applying a varnish containing a wax component to form an additional varnish layer; reducing the diameter of at least a portion of the can container where the surface coating layer is formed; a step of washing the can container to remove at least a portion of the wax component contained in the surface coating layer or the additional varnish layer; A method for manufacturing a can container comprising the steps of: [Item 23] The surface free energy of the can container after the step of removing at least a portion of the wax component is 30 mJ / m at a temperature of 25°C. 2 More than 50mJ / m 2 Below is the Item 23. A method for producing a can container according to Item 22. [Item 24] 24. The method for manufacturing a can container according to any one of items 20 to 23, further comprising a step of printing an ink composition to form a printed image layer. [Item 25] Item 25. The method for manufacturing a can container according to Item 24, further comprising forming a protective layer containing a resin component on the printed image layer. [Item 26] the step of forming the print image layer includes a step of fixing the can container to a can container holding member by chucking and printing the ink composition. Item 11 or any one of items 12 to 25 indirectly dependent on item 11, [Explanation of symbols]

[0184] 1 can body 2 Surface coating layer 3 Printing image layer 4. Receptor 5 Protective layer 6 Base image layer 7 Ink-repellent varnish layer 8 additional varnish layers 50 cans 100 Reduced diameter part 200 can body 300 Printing Department

Claims

1. A method for manufacturing a can container having a cylindrical can body, A surface coating layer is formed by applying a varnish containing a wax component to at least a part of the outer circumferential surface of the can body, or Alternatively, a step of forming a surface coating layer by coating at least a portion of the outer circumferential surface of the can body with a resin film, and then applying a varnish containing a wax component to form an additional varnish layer; reducing the diameter of at least a portion of the can container where the surface coating layer is formed; a step of heating the can container to evaporate at least a portion of the wax component contained in the surface coating layer or the additional varnish layer; A method for manufacturing a can container comprising the steps of:

2. The surface free energy of the can container after the step of evaporating at least a portion of the wax component is 30 mJ / m at a temperature of 25°C. ２ 50mJ / m or more ２ Below is the A method for manufacturing the can container according to claim 1.

3. A method for manufacturing a can container having a cylindrical can body, A surface coating layer is formed by applying a varnish containing a wax component to at least a part of the outer circumferential surface of the can body, or Alternatively, a step of forming a surface coating layer by coating at least a portion of the outer circumferential surface of the can body with a resin film, and then applying a varnish containing a wax component to form an additional varnish layer; reducing the diameter of at least a portion of the can container where the surface coating layer is formed; a step of washing the can container to remove at least a portion of the wax component contained in the surface coating layer or the additional varnish layer; A method for manufacturing a can container comprising the steps of:

4. The surface free energy of the can container after the step of removing at least a portion of the wax component is 30 mJ / m at a temperature of 25°C. ２ 50mJ / m or more ２ Below is the The method for manufacturing the can container according to claim 3.

5. The method for manufacturing a can container according to claim 1 , further comprising the step of printing an ink composition to form a printed image layer.

6. The method for manufacturing a can container according to claim 5 , further comprising the step of forming a protective layer containing a resin component on the printed image layer.

7. the step of forming the print image layer includes a step of fixing the can container to a can container holding member by chucking and printing the ink composition. The method for manufacturing the can container according to claim 5 or 6.

Images