Cap, bottle can body, and method for manufacturing the cap

Abstract

To provide a cap that can be gripped without any slipping of fingers when opened, a bottle can body and a method of manufacturing the cap.SOLUTION: The present invention relates to a bottomed cylindrical cap which has a top plate part and a peripheral wall part which extends cylindrically from an outer peripheral edge of the top plate part, and is fitted to a mouthpiece part of a bottle can body, and the cap has a resin layer formed by uniting a plurality of resin films including photopolymerizable material through photopolymerization. The resin layer is formed on an outer surface of the peripheral wall part intermittently at predetermined intervals.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cap for a bottle can body, a bottle can body, and a method for manufacturing a cap. [Background technology]

[0002] For example, a bottle-shaped can body having a can wall and a can bottom, and a shoulder portion with a reduced diameter on the opening side, is known as a can body into which contents such as beverages are filled and sealed. A mouth portion is formed at the tip of the shoulder portion of such a bottle-shaped can body for attaching a cap that closes the opening. A screw cap that is screwed onto a thread groove formed in the mouth portion is known as a cap that closes the bottle-shaped can body (see, for example, Patent Document 1).

[0003] However, when opening a bottle can with a screw-type cap, the cap must be rotated so as to break a cut portion called a bridge portion formed on the edge of the cap, and a relatively large rotational force must be applied. For this reason, caps with non-slip recesses and projections formed on the outer periphery are known so that fingers can grip the cap without slipping when opening (see, for example, Patent Document 2). Also known is a cap that can be opened without fingers slipping even if water droplets or the like are attached to the cap (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4908544 [Patent Document 2] Japanese Patent Application Publication No. 2018-177335 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-269381 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the invention disclosed in Patent Document 2, since the unevenness is formed on the cap itself which is made of metal, it is difficult to form unevenness deep enough to have an anti-slip effect. Furthermore, the invention disclosed in Patent Document 3 uses a water-repellent paint for the coating applied to the cap to prevent fingers from slipping when condensation forms on the cap, so the anti-slip effect is limited.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a cap, a bottle can body, and a method for manufacturing a cap that can be gripped without fingers slipping when opening the can. [Means for solving the problem]

[0007] In order to solve the above problems, the cap, bottle can body, and cap manufacturing method of one embodiment of the present invention propose the following means. That is, the cap of the present invention is a cylindrical cap with a bottom, which has a top plate portion and a peripheral wall portion extending cylindrically from the outer periphery of the top plate portion, and is attached to the mouth portion of a bottle can body, and the cap has a resin layer formed by integrating a plurality of resin films containing a photopolymerizable material by photopolymerization, and the laminated coating film portion is formed intermittently at predetermined intervals on the outer surface of the peripheral wall portion. and at least one of the resin films constituting the resin layer, which is located above the lowermost resin film closer to the peripheral wall portion, has an area on one side larger than the area on one side of the lowermost resin film. It is characterized by:

[0008] According to the cap of the present invention, by intermittently forming a resin layer consisting of multiple resin films on the peripheral wall portion, it is possible to form unevenness that is deeper than when unevenness is formed on the cap body itself by pressing, etc., so that when rotating the cap to open it, the cap can be gripped and rotated without the fingers slipping.

[0009] Furthermore, since the resin layer is made up of multiple resin films containing photopolymerizable materials that are integrated together through photopolymerization, even if condensation forms on the cap when, for example, a cooled beverage is placed inside, the cap can be gripped and rotated without fingers slipping, compared to metal irregularities formed on the cap body itself.

[0010] In addition, in the present invention, a knurl portion that bulges circumferentially so as to widen the outer diameter may be integrally formed on the peripheral wall portion near the top plate portion, and the resin layer may be formed intermittently on the knurl portion.

[0011] In addition, in the present invention, a screw groove extending at a predetermined lead angle is formed on the peripheral wall portion, and the resin layer may be formed intermittently along the lead angle on convex portions that protrude outward from the outer surface of the peripheral wall portion, among the irregularities that make up the screw groove.

[0013] The bottle can body of the present invention has a body portion formed in a cylindrical shape centered on a can axis, a bottom portion closing one end of the body portion, a shoulder portion extending from the other end of the body portion so as to reduce in diameter, and a mouth portion extending from the shoulder portion toward the opening of the other end, and the bottle can body has a resin layer formed by integrating a plurality of resin films containing a photopolymerizable material by photopolymerization, and the resin layer is formed intermittently at predetermined intervals on the outer surface of the body portion. and an area of ​​one surface of at least one resin film located above the bottommost resin film near the body portion among the plurality of resin films constituting the resin layer is larger than an area of ​​one surface of the bottommost resin film. It is characterized by:

[0014] According to the bottle can body of the present invention, by intermittently forming a resin layer on the body portion in which multiple resin films containing a photopolymerizable material are integrated by photopolymerization, it is possible to form irregularities with greater depth than, for example, when irregularities are formed on the body portion itself by pressing, etc., so that when gripping the body portion and rotating the cap to open it, the bottle can body can be gripped without fingers slipping.

[0015] Furthermore, since the resin layer is made up of multiple laminated resin films, even if condensation occurs on the body of the bottle due to the inclusion of a chilled beverage or the like, the fingers can be gripped without slipping, compared to metal irregularities formed on the body itself.

[0016] In the present invention, the resin layer may form a plurality of elongated ridges extending parallel to the can axis, and may be arranged intermittently at predetermined intervals in the circumferential direction of the body portion.

[0018] The cap manufacturing method of the present invention is a cap manufacturing method described in each of the above paragraphs, and includes a resin layer forming process for forming the resin layer on the outer surface of the peripheral wall portion, and is characterized in that the resin layer forming process photopolymerizes adjacent resin films when a resin liquid containing a photopolymerizable material is ejected by a droplet ejection device to form multiple overlapping resin films. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a cap that can be gripped without fingers slipping when opening, a bottle can body, and a method for manufacturing a cap. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is an external perspective view showing a cap according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a partially cutaway view of the cap of FIG. [Figure 3] FIG. 2 is an enlarged cross-sectional view of a main part of a resin layer in the first embodiment. [Figure 4] FIG. 10 is a partially cutaway view of a cap according to a second embodiment. [Figure 5] FIG. 11 is an enlarged cross-sectional view of a main part of a resin layer in a third embodiment. [Figure 6] 1 is a partially cutaway view showing a bottle can body according to an embodiment of the present invention. [Figure 7] FIG. 2 is an enlarged cross-sectional view of a main part of a resin layer of a bottle can body. [Figure 8]FIG. 2 is an external perspective view showing a bottle can body with a cap. [Figure 9] FIG. 2 is a schematic diagram illustrating an example of an inkjet printer (droplet ejection device) used in the resin layer forming step. DETAILED DESCRIPTION OF THE INVENTION

[0021] A cap, a bottle can body, and a method for manufacturing a cap, which are one embodiment of the present invention, will be described below with reference to the drawings. Note that the embodiment shown below is specifically described to provide a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. Furthermore, the drawings used in the following description may show essential parts enlarged for convenience in order to make the features of the present invention easier to understand, and the dimensional proportions of each component may not necessarily be the same as those in reality.

[0022] (Cap: First embodiment) A cap according to a first embodiment of the present invention will be described. Fig. 1 is an external perspective view showing a cap according to a first embodiment of the present invention, Fig. 2 is a partially cutaway view of the cap of Fig. 1, and Fig. 3 is an enlarged cross-sectional view of a main part of a resin layer in the first embodiment. The cap 10 of this embodiment is a member that is attached to the mouth portion of a bottle can body, which will be described later, to close the bottle can body.

[0023] The cap 10 has a cap body 1 formed integrally with a disk-shaped top plate 2, a peripheral wall 3 extending cylindrically from the periphery of the top plate 2 toward the lower end (lower side in FIG. 2) centered on the cap center line O, and a resin layer 13 formed on a knurl portion 5 described below. The cap body 1 is formed of a metal material such as aluminum or an aluminum alloy, and has a bottomed cylindrical shape centered on the cap center line O.

[0024] A disk-shaped resin liner 4 is disposed on the inner surface (lower surface) 2a of the top plate 2. The liner 4 has a multilayer structure including a large-diameter sliding layer 4a made of a hard resin, such as polyethylene or polypropylene, and disposed on the top plate 2 side in a non-adhered state with the inner surface 2a, and a smaller-diameter sealing layer 4b made of an elastomer resin and softer than the sliding layer 4a, and disposed on the opposite side of the sliding layer 4a from the top plate 2, either directly or via an intermediate layer such as a barrier layer. The sliding layer 4a is flat and has a substantially uniform thickness, while the sealing layer 4b has a thick outer periphery and a thin inner periphery recessed toward the top plate 2, with the step between the inner periphery and the outer periphery tapering toward the top plate 2 as it approaches the inner periphery.

[0025] Furthermore, on the peripheral wall 3 of the cap body 1, at the upper end side closer to the top plate 2, there is formed a knurled portion 5 that bulges radially outward relative to the cap center line O toward the lower end, and a groove 6 that is connected to the lower end of this knurled portion 5 and recesses inward, and these grooves 6 are formed around the peripheral wall 3 around the cap center line O. Furthermore, on the lower end side of the peripheral wall 3 opposite the top plate 2, there are formed, in order from the upper end side to the lower end side, a bead 7 that also bulges outward, a frangible portion 8 that has a smaller outer diameter than this bead 7, and a cylindrical flare (open end) 9 that has a larger outer diameter than this frangible portion 8 and extends to the lower end of the cap body 1.

[0026] The fragile portion 8 is formed with a plurality of slits 8a at equal intervals in the circumferential direction, extending in a side view and recessed radially inward relative to the cap center line O, and the portion between these slits 8a is formed as a bridge portion 8b. In the slits 8a, a slit 8c is formed on the long side on the upper end side thereof, penetrating the peripheral wall portion 3. In addition, the flare 9 is wrapped around the lower end of a bulge formed on the lower end side of the male thread portion of the mouth when capping the mouth portion of the bottle can body, which will be described later.

[0027] Furthermore, the portion between the groove 6 on the upper end side of the peripheral wall portion 3 and the bead 7 on the lower end side is a female thread formation portion 12 where a female thread portion that screws into the male thread portion of the cap attachment portion is formed when capping the mouth portion of the bottle can body. The outer diameter of this female thread formation portion 12 is a substantially constant outer diameter that is larger than the outer diameter of the groove 6 and smaller than the outer diameter of the bead 7.

[0028] On the other hand, in the knurl portion 5, a liner locking portion 11 is formed in a portion of the knurl portion 5 closer to the top plate portion 2, so that the peripheral wall portion 3 of the cap body 1 is recessed inward, and the liner locking portion 11 protrudes radially inward relative to the cap center line O, but does not penetrate the peripheral wall portion 3. The radius of the cylindrical surface centered on the cap center line O that is inscribed in the liner locking portion 11 is smaller than the radius of the outer peripheral edge of the liner 4 (the outer peripheral edge of the sliding layer 4a) but larger than the radius of the outer peripheral edge of the sealing layer 4b. The liner locking portion 11 locks the outer peripheral edge of the sliding layer 4a of the liner 4, preventing it from coming off, and holds it between the inner surface 2a of the top plate portion 2.

[0029] Of the knurl portion 5 that bulges in two stages, the width of the step on the lower end side of the peripheral wall portion 3 in the direction of the cap center line O is larger than the width of the step on the upper end side in the direction of the cap center line O. In addition, a plurality of island-shaped resin layers 13 are intermittently formed in this knurl portion 5 at predetermined intervals.

[0030] The resin layer 13 is formed by forming a resin film 14 made of a resin that is entirely composed of a polymerizable compound or that contains a polymerizable compound in part, such as a photo-radical polymerization type ultraviolet curing resin, on the surface of the peripheral wall portion 3 of the cap body 1 using a droplet ejection device, such as an inkjet printer, and then stacking the layers one by one while curing each layer through a photopolymerization reaction caused by UV irradiation, or by integrating multiple stacked resin films 14, 14... through a photopolymerization reaction.

[0031] When UV light is irradiated onto each layer during the formation of the resin film 14, if the reaction is suppressed to a certain rate by reducing the irradiation intensity of the UV light or shortening the irradiation time, a photopolymerization reaction can be carried out on the next resin film 14 to be stacked, and all of the stacked resin films 14 can be integrated to form the resin layer 13.

[0032] The resin film 14 before polymerization (resin liquid sprayed from the droplet spraying device) for forming the second resin layer 13 contains a photopolymerizable material. Examples of the photopolymerizable material contained in the resin film 14 before polymerization include at least one monomer or oligomer of acrylic resin (including methacrylic resin), epoxy resin, urethane resin, vinyl resin (including vinyl chloride resin, polyvinyl alcohol resin, and vinyl acetate resin), polyester resin, polyester amino resin, silicone resin, and polyolefin resin.

[0033] More specifically, the photopolymerizable material contained in the pre-polymerized resin film 14 can be monofunctional to oligofunctional prepolymers such as acrylic monomers, methacrylic monomers, and vinyl compounds. In addition, the photopolymerizable oligomer can be, for example, epoxy acrylate, aliphatic and aromatic urethane acrylate, polyester acrylate, acrylic oligomer, etc.

[0034] Furthermore, by integrating multiple resin films 14 by photopolymerization of a photopolymerizable material to form a resin layer 13, shrinkage due to evaporation of the solvent when drying, such as in water-based paints or oil-based paints, can be prevented.

[0035] The resin film 14 before polymerization when forming the resin layer 13 can be formed by ejecting a resin paint containing a polymerizable unsaturated compound from a droplet ejection device, for example, an inkjet head. If an ultraviolet-curable resin paint containing a polymerizable unsaturated compound is used as the resin film 14, shrinkage of the coating film due to solvent evaporation during drying, as occurs when water-based or oil-based paints are used, can be prevented.

[0036] Examples of the polymerizable unsaturated compound include acrylic monomers, methacrylic monomers, and vinyl compounds, and can be monofunctional to oligofunctional prepolymers. Examples of the polymerizable oligomer include epoxy acrylates, aliphatic and aromatic urethane acrylates, polyester acrylates, and acrylic oligomers.

[0037] The resin layer 13 of this embodiment is formed so that the area of ​​one side of at least one of the multiple resin films 14, 14..., which is located above the lowest resin film 14a in contact with the surface of the peripheral wall portion 3, is smaller than the area of ​​one side of the lowest resin film 14.

[0038] That is, in this embodiment, the multiple resin films 14, 14... are formed so that the area of ​​one surface of each resin film 14 gradually decreases from the lowest resin film 14a near the peripheral wall portion 3 to the highest resin film 14n. As a result, each resin layer 13 is formed in a trapezoidal shape.

[0039] The thickness of the resin layer 13 protruding from the surface of the knurled portion 5 may be, for example, 0.03 mm or more and 1 mm or less. If the thickness of the resin layer 13 protruding is less than 0.03 mm, there is a concern that the anti-slip performance may be reduced. If the thickness of the resin layer 13 protruding is more than 1 mm, there is a concern that the resin layer 13 may partially peel off.

[0040] A base layer (not shown) may be formed on the outer surface of the cap body 1, including the knurl portion 5. The base layer may be, for example, a thin film formed of an epoxy resin or a thermosetting acrylic resin. More specifically, the epoxy resin may be any epoxy resin commonly used for paints, without any particular limitations. Examples of such epoxy resins include various epoxy resins that are commonly available commercially, such as epi-bis, novolac, β-methylepicro, cyclic oxirane, glycidyl ether, glycidyl ester, polyglycol ether, glycol ether, epoxidized fatty acid ester, polycarboxylic acid ester, aminoglycidyl, and resorcinol.

[0041] Such an underlayer may be formed to have a thickness of, for example, about 3 μm to 10 μm. The underlayer may be formed by applying the above-mentioned resin with a roll coater, for example.

[0042] When forming the base layer, if the resin film 14 is formed as the resin layer 13 using a resin paint containing 0.1% to 2% of a polymerizable oligomer of a polyester resin that has good adhesive compatibility with the base layer, the interface between the resin layer 13 formed on the base layer can be bonded by photopolymerization, for example, photoradical polymerization or photocationic polymerization. This prevents the resin layer 13 from peeling off from the base layer even when external stress is applied to the resin layer 13.

[0043] Furthermore, by forming the resin layer 13 from the resin film 14 colored in any color tone, the design of the cap 10 can be improved. Furthermore, by coloring the resin layer 13 in blue or red, it is possible to indicate, for example, the temperature range (hot or cold) of the beverage contained in the bottle can.

[0044] According to the cap 10 of this embodiment having the above-described configuration, by intermittently forming a resin layer 13 on the peripheral wall portion 3 by integrating multiple resin films 14, 14... by photopolymerization, it is possible to form unevenness with greater depth than when unevenness is formed on the cap body itself by pressing or the like. Therefore, when rotating the cap 10 to open it, the cap 10 can be gripped and rotated without the fingers slipping.

[0045] Furthermore, since the resin layer 13 is made up of multiple resin films 14, 14... that are integrated together by photopolymerization, even if condensation forms on the cap 10 when a cooled beverage or the like is placed inside, the fingers can grip and rotate the cap 10 without slipping, compared to metal irregularities formed on the cap body itself.

[0046] (Cap: Second embodiment) A cap according to a second embodiment of the present invention will now be described. The same components as those of the cap in the first embodiment are given the same numbers, and redundant explanations will be omitted. FIG. 4 is a partially cutaway view showing a cap according to a second embodiment of the present invention. The cap 20 of this embodiment has a cap body 1 which is integrally formed with a disk-shaped top plate portion 2 and a peripheral wall portion 3 which extends cylindrically from the periphery of the top plate portion 2 toward the lower end side (lower side in Figure 4) centered on the cap center line O, and a resin layer 13 formed on the screw portion 25.

[0047] The peripheral wall 3 of the cap body 1 is formed with a knurled portion 5, and this knurled portion 5 and a groove 6. In addition, on the lower end side of the peripheral wall 3 opposite the top plate portion 2, there are formed, in order from the upper end side to the lower end side, a bead 7 that also bulges outward, a frangible portion 8 that has a smaller outer diameter than the bead 7, and a cylindrical flare (open end) 9 that has a larger outer diameter than the frangible portion 8 and extends to the lower end of the cap body 1.

[0048] The fragile portion 8 is formed with a plurality of slits 8a at equal intervals in the circumferential direction, extending in a side view and recessed radially inward relative to the cap center line O, and the portion between these slits 8a is formed as a bridge portion 8b. In the slits 8a, a slit 8c is formed on the long side on the upper end side thereof, penetrating the peripheral wall portion 3. In addition, the flare 9 is wrapped around the lower end of a bulge formed on the lower end side of the male thread portion of the cap attachment portion when capping the mouth portion of the bottle can body, which will be described later.

[0049] In the area between the groove 6 on the upper end side of the peripheral wall portion 3 and the bead 7 on the lower end side, the unevenness of the female screw portion (thread groove) 22 that screws into the male screw portion of the cap mounting portion when capping the bottle can body to the cap mounting portion is formed in a spiral shape so as to extend at a predetermined lead angle.

[0050] Among the irregularities that make up this female thread portion 22, a plurality of island-shaped resin layers 13 are intermittently formed at predetermined intervals on the convex portions 22a that protrude outward from the outer surface of the peripheral wall portion 3. That is, the resin layers 13 are intermittently arranged at a predetermined lead angle along the extension direction of the convex portions 22a of the female thread portion 22. The resin layer 13 is made up of a plurality of resin films 14, 14... that are integrated together by photopolymerization.

[0051] The resin layer 13 of this embodiment is formed so that the area of ​​one side of at least one of the multiple resin films 14, 14..., which is located above the lowest resin film 14a in contact with the surface of the peripheral wall portion 3, is smaller than the area of ​​one side of the lowest resin film 14.

[0052] That is, in this embodiment, the multiple resin films 14, 14... are formed so that the area of ​​one surface of each resin film 14 gradually decreases from the lowest resin film 14a closest to the peripheral wall portion 3 to the highest resin film 14n. As a result, each resin layer 13 is formed in a trapezoidal shape with side surfaces sloping in a stepped manner.

[0053] The thickness of the resin layer 13 protruding from the surface of the protrusion 22a may be, for example, 0.03 mm or more and 1 mm or less. If the thickness of the resin layer 13 protruding is less than 0.03 mm, there is a concern that the anti-slip performance may be reduced. If the thickness of the resin layer 13 protruding is more than 1 mm, there is a concern that partial peeling of the resin layer 13 may occur.

[0054] Even in the cap 20 of this embodiment having the above-described configuration, by intermittently forming a resin layer 13 on the peripheral wall portion 3 by integrating multiple resin films 14, 14... by photopolymerization, it is possible to form a finger grip when opening the cap 20 on the female screw portion (thread groove) 22, where it is difficult to form irregularities on the cap body itself by pressing or the like, and the cap 20 can be gripped and rotated without fingers slipping.

[0055] (Cap: Third embodiment) A cap according to a third embodiment of the present invention will now be described. The same components as those of the caps of the first and second embodiments are given the same numbers, and redundant explanations will be omitted. FIG. 5 is an enlarged cross-sectional view of a main part of a resin layer in the third embodiment. In the first and second embodiments described above, the shape of the resin layer 13 is trapezoidal, but the resin layer 23 in this embodiment is formed so that the area of ​​one side of at least one resin film 24, among the multiple resin films 24, 24..., which is located above the lowest resin film 24a in contact with the surface of the peripheral wall portion 3, is larger than the area of ​​one side of the lowest resin film 24.

[0056] That is, in this embodiment, the multiple resin films 24, 24... are formed so that the area of ​​one surface of each resin film 24 gradually increases from the lowest resin film 24a closest to the peripheral wall portion 3 to the highest resin film 24n. As a result, each resin layer 23 is formed in an inverted trapezoidal shape.

[0057] The thickness of the resin layer 23 protruding from the surface of the peripheral wall 3 may be, for example, 0.03 mm or more and 1 mm or less. If the thickness of the resin layer 23 protruding is less than 0.03 mm, there is a concern that the anti-slip performance may be reduced. If the thickness of the resin layer 23 protruding is more than 1 mm, there is a concern that the resin layer 23 may partially peel off. The inverted trapezoidal resin layer 23 as in this embodiment may be formed on the knurl portion as in the first embodiment, or may be formed on the surface of the convex portion of the female screw portion as in the second embodiment.

[0058] According to the resin layer 23 of this embodiment, by intermittently forming the resin layer 23 on the peripheral wall portion 3 of the cap by integrating multiple resin films 24, 24... by photopolymerization, the depth of the unevenness can be made larger compared to when unevenness is formed on the cap body itself by pressing or the like, and the cap can be gripped and rotated without fingers slipping.

[0059] Furthermore, by making the shape of the resin layer 23 an inverted trapezoid, it becomes easier to retain water droplets caused by condensation between adjacent resin layers 23, so that even when a chilled beverage or the like is contained, the cap can be grasped and rotated without the fingers slipping due to the water droplets.

[0060] (Bottle can body) A bottle can body according to one embodiment of the present invention will be described. Fig. 6 is a partially cutaway view showing a bottle can body according to one embodiment of the present invention, and Fig. 7 is an enlarged cross-sectional view of a main part of the resin layer of the bottle can body. The bottle can body 30 of this embodiment is formed in a roughly multi-stage, bottomed cylindrical shape centered on a can axis C, and includes a bottom 32 that closes one end of a cylindrical body 35, and an outer peripheral portion 33 that is formed integrally with the bottom 32 and extends from the outer peripheral edge of the bottom 32 to the upper end side (upward in Figure 6).

[0061] The bottom 32 has a dome portion 32a in the center that is recessed inward in the direction of the can axis C (toward the upper end of the bottle can body 30) and has an approximately arc-shaped cross section. At the outer periphery of this dome portion 32a, an annular protrusion 32b is formed continuously in the circumferential direction around the can axis C, protruding outward in the direction of the can axis C (toward the lower end of the bottle can body 30).

[0062] The outer periphery 33 is formed, in this order from the bottom 32 toward the opening 34 at the upper end of the bottle can body 30, with a cylindrical body 35 centered on the can axis C, a truncated conical shoulder portion 36 that gradually reduces in diameter at a constant incline from the other end of the body 35 toward the upper end, a cylindrical neck 37 that extends further toward the upper end from the shoulder portion 36, and a mouth portion 38 that includes: a bulge 38a that protrudes outward from the upper end of the neck 37, a threaded portion 38b, a reduced diameter portion 38c that gradually reduces in diameter from the upper end of the threaded portion 38b toward the upper end, and a curled portion 38d formed by folding the upper part of the reduced diameter portion 38c toward the outer periphery and then back toward the lower end.

[0063] A plurality of resin layers 43, 43... are formed on the body 35 of the bottle can body 30. That is, each resin layer 43 in this embodiment forms an elongated ridge extending parallel to the can axis C, and is formed intermittently at predetermined intervals along the circumferential direction of the body 35. In this embodiment, the resin layer 43 is formed in the upper region of the body 35. Note that the resin layer 43 may also be formed in the lower region of the body 35 or over the entire body 35, and the formation region is not limited.

[0064] The resin layer 43 is made up of a plurality of resin films 44, 44 . . . that are integrated together by photopolymerization. The photopolymerizable material contained in the pre-polymerized resin film 44 can be monofunctional to oligofunctional prepolymers such as acrylic monomers, methacrylic monomers, and vinyl compounds. In addition, photopolymerizable oligomers such as epoxy acrylates, aliphatic and aromatic urethane acrylates, polyester acrylates, and acrylic oligomers can be used.

[0065] Furthermore, by integrating multiple resin films 44 through photopolymerization using a photopolymerizable material to form a resin layer 43, it is possible to prevent shrinkage due to solvent evaporation during drying, as occurs when using water-based paint or oil-based paint, for example.

[0066] The resin film 44 can be formed by ejecting a resin paint containing a polymerizable unsaturated compound from a droplet ejection device, such as an inkjet head. In this case, the resin films 44 are polymerized together during the coating film formation process, thereby integrating the multiple resin films 44, 44, to form the resin layer 43. If an ultraviolet-curable resin paint containing a polymerizable unsaturated compound is used as the resin film 44, it is possible to prevent the coating film from shrinking due to solvent evaporation during drying, as occurs when water-based or oil-based paints are used.

[0067] The resin layer 43 of this embodiment is formed so that the area of ​​one side of at least one of the multiple resin films 44, 44... that is located above the lowest resin film 44a that contacts the outer surface 35a of the body 35 is smaller than the area of ​​one side of the lowest resin film 44.

[0068] That is, in this embodiment, the multiple resin films 44, 44... are formed so that the area of ​​one surface of each resin film 44 gradually decreases from the lowest resin film 44a closest to the outer surface 35a of the body 35 to the highest resin film 44n. As a result, each resin layer 43 is formed in a trapezoidal shape with side surfaces sloping in a stepped manner.

[0069] The thickness of the resin layer 43 protruding from the outer surface 35a of the body 35 may be, for example, 0.03 mm or more and 1 mm or less. If the thickness of the resin layer 43 protruding is less than 0.03 mm, there is a concern that the anti-slip performance may be reduced. If the thickness of the resin layer 43 protruding is more than 1 mm, there is a concern that the resin layer 43 may partially peel off.

[0070] In addition to the shape shown in FIG. 7, the resin layer 43 may be formed in a trapezoidal shape, for example, as shown in FIG. 3, so that the area of ​​one side of each resin film gradually decreases from the bottom resin film to the top resin film.

[0071] A base layer (not shown) may be formed on the outer surface of the bottle can body 30. The base layer may be, for example, a thin film formed of an epoxy resin or a thermosetting acrylic resin. More specifically, the epoxy resin may be any epoxy resin commonly used for paints, without any particular restrictions. Examples of such epoxy resins include various epoxy resins that are commonly available commercially, such as epi-bis type, novolac type, β-methylepicro type, cyclic oxirane type, glycidyl ether type, glycidyl ester type, polyglycol ether type, glycol ether type, epoxidized fatty acid ester type, polycarboxylic acid ester type, aminoglycidyl type, and resorcinol type.

[0072] Such an underlayer may be formed to have a thickness of, for example, about 3 μm to 10 μm. The underlayer may be formed by applying the above-mentioned resin with a roll coater, for example.

[0073] When forming the base layer, if resin film 44 is formed as resin layer 43 using a resin paint containing 0.1% to 2% of a polymerizable oligomer of a polyester resin that has good adhesive compatibility with the base layer, the interface between resin layer 43 formed on this base layer can be bonded by photopolymerization, for example, photoradical polymerization or photocationic polymerization. This prevents peeling from the base layer even when external stress is applied to resin layer 43.

[0074] Furthermore, by forming the resin layer 43 from a resin film 44 colored in any color tone, the design of the bottle-can body 30 can be improved. Furthermore, by coloring the resin layer 43 blue or red, it is possible to indicate, for example, the temperature range (heated or cooled) of the beverage contained in the bottle-can body 30.

[0075] According to the bottle can body 30 of this embodiment configured as described above, a resin layer 43 made by integrating a plurality of resin films 44, 44... is intermittently formed on the outer surface 35a of the body portion 35, so that when the cap attached to the mouth portion 38 of the bottle can body 30 is turned to open it, the resin layer 43 can be used as a fingerhold to grip the body portion 35 without the fingers slipping.

[0076] Furthermore, since the resin layer 43 is made up of a plurality of resin films 44, 44... that are integrated together by photopolymerization using a photopolymerizable material, even if condensation forms on the bottle can body 30 due to the storage of a cooled beverage or the like, the bottle can body 30 can be held without fingers slipping by gripping the portion where the resin layer 43 is formed.

[0077] (Bottle can with cap) The bottle can with a cap will now be described. FIG. 8 is an external perspective view showing a bottle can with a cap according to one embodiment. The capped bottle can body 50 of this embodiment is formed by, for example, attaching the cap 10 of the first embodiment to the mouth portion 38 of the bottle can body 30 of the above-described embodiment.

[0078] In the capped bottle can body 50 of this embodiment having such a configuration, a resin layer 13 is formed on the knurl portion 5 of the cap 10, which is made by laminating a plurality of resin films 14, 14... (see FIG. 3) containing a photopolymerizable material and integrating them by photopolymerization. Also, a resin layer 43 is formed on the body portion 35 of the bottle can body 30, which is made by laminating a plurality of resin films 44, 44... containing a photopolymerizable material and integrating them by photopolymerization.

[0079] With the capped bottle can body 50 configured as described above, for example, when a person holds the bottle can body 30 with one hand and the cap 10 with the other and turns the cap 10 to open it, even if the surfaces are covered with condensation due to cooled liquid contents, the resin layers 13 and 44 prevent fingers from slipping and allow the bottle can body 30 and the cap 10 to be securely gripped, respectively. This makes it easy to open the capped bottle can body 50.

[0080] (Cap manufacturing method) A method for manufacturing a cap according to one embodiment of the present invention will now be described. For example, when manufacturing the cap 10 of the first embodiment described above, a cap body 1 formed by pressing an aluminum alloy plate is prepared, and multiple resin films 14 are laminated on the knurled portion 5 of the cap body 1 using an inkjet printer to form a resin layer 13 (resin layer formation process).

[0081] When forming the resin layer 13, a droplet ejection device capable of ejecting a resin liquid for forming the resin film 14 on the curved peripheral wall portion 3 of the cap 10, such as an inkjet printer having an inkjet head, may be used. The resin liquid to be applied may contain an ultraviolet-curable resin.

[0082] For example, monofunctional to oligofunctional prepolymers such as acrylic monomers, methacrylic monomers, and vinyl compounds can be used as the photopolymerizable material used in the resin liquid for forming the resin film 14 that constitutes the second resin layer 13. In addition, epoxy acrylates, aliphatic and aromatic urethane acrylates, polyester acrylates, acrylic oligomers, etc. can be used as polymerizable oligomers.

[0083] In this embodiment, an inkjet printer P (droplet ejection device) with six inkjet heads is used as shown in Fig. 9, but the number of inkjet heads used is limited to improve productivity. For example, of the C, M, Y, and K heads used for color printing, only the M (magenta) head is used, and two heads V are allocated to further laminate a transparent resin film (varnish).

[0084] Then, while rotating each cap body 1, resin liquid containing a photopolymerizable material is ejected from each head to form pre-polymerized resin films 14a (lowest layer) to 14n (uppermost layer). At this time, the area of ​​one side of each resin film 14 (see FIG. 3) gradually decreases from the lowest resin film 14a toward the uppermost resin film 14n, and the resin liquid is ejected so that the cross section forms a trapezoidal shape, forming the resin film 14 of each layer.

[0085] Thereafter, for example, ultraviolet rays are irradiated from ultraviolet irradiation units UV formed at positions opposite each head, thereby photopolymerizing the unpolymerized resin films 14a-14n ejected by each head, and bonding each adjacent lower resin film 14 to each other by photopolymerization. As a result, a resin layer 13 is formed that is firmly bonded to the first resin layer 12 by photopolymerization.

[0086] In forming the resin film 14, as described above, an ultraviolet irradiation unit UV may be arranged corresponding to each inkjet head, and each time a resin film 14 is formed, it may be polymerized with the underlying resin film 14, or all of the unpolymerized resin films 14 may be stacked and then polymerized all at once.

[0087] Furthermore, when forming a base layer on the cap 10, a resin paint containing 0.1% to 2% polymerizable oligomer of polyester-based resin, which has good adhesive properties, can be used as a resin liquid and ejected from an inkjet head to laminate multiple resin films 14, thereby photopolymerizing the bottommost resin film 14a and the base layer to form a firmly bonded resin layer 13.

[0088] Although one embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0089] 1...Cap body 2...Top plate 3...Peripheral wall part 4. Liner 5...Nar Department 10...Cap 13...Resin layer 14...Resin film 30...Bottle can body 32...Bottom 33...Outer periphery 35...Torso 36...Shoulder part 38...Mouth part 50...Bottle can with cap

Claims

1. A cylindrical cap with a bottom has a top plate portion and a peripheral wall portion extending cylindrically from the outer periphery of the top plate portion, and is attached to a mouth portion of a bottle can body, the cap has a resin layer formed by integrating a plurality of resin films containing a photopolymerizable material by photopolymerization; the resin layer is formed intermittently at predetermined intervals on the outer surface of the peripheral wall portion, A cap characterized in that the area of ​​one side of at least one of the multiple resin films that make up the resin layer, which is located above the lowest resin film closer to the peripheral wall portion, is larger than the area of ​​one side of the lowest resin film.

2. A knurled portion is integrally formed on the peripheral wall portion near the top plate portion, the knurled portion expanding in the circumferential direction so as to widen the outer diameter, The cap according to claim 1 , wherein the resin layer is intermittently formed on the knurl portion.

3. A screw groove extending at a predetermined lead angle is formed on the peripheral wall portion, The cap described in claim 1 or 2, characterized in that the resin layer is formed intermittently along the lead angle on convex portions that protrude outward from the outer surface of the peripheral wall portion, among the concave and convex portions that constitute the screw groove.

4. A bottle-shaped can body has a body portion formed in a cylindrical shape centered on a can axis, a bottom portion closing one end of the body portion, a shoulder portion extending from the other end of the body portion so as to reduce in diameter, and a mouth portion extending from the shoulder portion toward an opening at the other end, The bottle can body has a resin layer formed by integrating a plurality of resin films containing a photopolymerizable material by photopolymerization, the resin layer is formed intermittently at predetermined intervals on the outer surface of the body portion, A bottle can body characterized in that, among the plurality of resin films constituting the resin layer, the area of ​​one side of at least one resin film located above the lowest resin film closer to the body portion is larger than the area of ​​one side of the lowest resin film.

5. 5. The bottle-shaped can body according to claim 4, wherein the resin layer forms elongated ridges extending parallel to the can axis, and the resin layer is arranged intermittently at predetermined intervals in the circumferential direction of the body portion.

6. A method for manufacturing the cap according to any one of claims 1 to 3, comprising the steps of: a resin layer forming step of forming the resin layer on the outer surface of the peripheral wall portion, The resin layer forming process is a method for manufacturing a cap, characterized in that when a resin liquid containing a photopolymerizable material is ejected using a droplet ejection device to form multiple overlapping resin films, adjacent resin films are photopolymerized together.

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