JP2023124249A - Coated aluminum-made container, and method for manufacturing coated aluminum-made container - Google Patents

Abstract

To provide a coated aluminum-made container which can keep high productivity even when using a printing method by droplet discharge, and has high designability, and a method for manufacturing the coated aluminum-made container.SOLUTION: A coated aluminum-made container has an aluminum-made container body, a first resin layer formed so as to cover the surface of the container body, and a second resin layer formed in a part of the surface of the first resin layer, wherein the second resin layer is formed of integration of a plurality of resin films containing a photopolymerizable material by photopolymerization, and a part of the first resin layer is exposed to the outside.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a coated aluminum container obtained by coating an aluminum container, and a method for manufacturing the coated aluminum container.

For example, various aluminum containers, especially aluminum cans, are widely used for selling beverages and the like. The outer surface coating and the inner surface coating are applied to the container body of such an aluminum can. In exterior painting, an undercoating with a base paint is usually performed, and after the undercoating is baked and dried, an arbitrary design is printed and the exterior surface finish coating is performed.

In recent years, when printing an arbitrary design on a curved metal surface such as an aluminum can container body, it has been considered to apply an inkjet printing method using a droplet ejection device, for example, an inkjet printer (for example, See Patent Document 1). The inkjet printing method facilitates multicolor expression by increasing the number of nozzle heads, and can print designs with vivid color tones. Moreover, the inkjet printing method can print without preparing a printing plate.
On the other hand, in the inkjet printing method, since fine ink droplets are ejected from a nozzle head, when printing a wide area, the printing time is longer than offset printing, screen printing, and the like.

JP 2018-68361 A

In the invention disclosed in Patent Document 1, after forming a primer layer as a base on the body portion, a design construction layer expressing an arbitrary design is superimposed on a part of this primer layer, and further the primer layer is exposed. A protective layer is formed to cover the part and the design construction layer. However, in addition to the design construction layer, when the protective layer is formed by the inkjet printing method so as to cover the exposed portion of the primer layer and the design construction layer, the printing time is long, and cans are manufactured in large quantities at high speed. There is a problem that the productivity decreases when applied to the printing of In addition, when the protective layer is formed so as to cover the exposed portion of the primer layer and the design construction layer, the three-dimensional effect is lowered and the effect of the design is diminished.

The present invention has been made in consideration of such circumstances, and it is possible to maintain high productivity even by using a printing method using droplet ejection, and a painted aluminum container with high design, and It is an object of the present invention to provide a method for manufacturing painted aluminum containers.

In order to solve the above problems, the present invention proposes the following means.
That is, the coated aluminum container of the present invention includes an aluminum container body, a first resin layer formed so as to cover the surface of the container body, and a part of the surface of the first resin layer. and a second resin layer, wherein the second resin layer is formed by integrating a plurality of resin films containing a photopolymerizable material by photopolymerization, and a part of the first resin layer is It is characterized by being exposed to the outside.

According to the present invention, compared with a conventional painted aluminum container designed with a flat coating film having poor three-dimensionality, the first resin obtained by integrating a plurality of resin films by photopolymerization With the second resin layer formed so as to protrude from the layer, it is possible to realize a coated aluminum container with a three-dimensional design and high designability.

In addition, according to the coated aluminum container of the present invention, since a part of the first resin layer is exposed to the outside, it is possible to form a protective film covering the exposed parts of the second resin layer and the first resin layer. Even if the container body is painted by a droplet discharge printing method that takes longer than offset printing, the printing time for the protective film can be omitted, and the coated aluminum container can be used. can prevent a decrease in productivity.

Further, in the present invention, the first resin layer may contain a thermosetting resin and a photopolymerizable material, and at least the lowermost resin film and the first resin layer may be bonded by photopolymerization.

Further, in the present invention, the photopolymerizable material may be a photopolymerizable oligomer or a photopolymerizable monomer that undergoes photoradical polymerization or photocationic polymerization.

Moreover, in this invention, the said 2nd resin layer may contain visible light transmissive resin.

Further, in the present invention, between the container body and the first resin layer, between the first resin layer and the second resin layer, or between the resin films of the second resin layer , at least one of which may further have a printed layer formed thereon.

Moreover, in the present invention, a filler may be further dispersed in the first resin layer.

Further, in the present invention, the thickness of the second resin layer may be 0.03 mm or more and 1 mm or less.

Further, in the present invention, the container body includes a bottom portion, a cylindrical portion extending cylindrically from the outer peripheral edge of the bottom portion, a shoulder portion whose diameter decreases upward from the upper end of the cylindrical portion, and further from the shoulder portion. A neck portion extending upward and a cap attachment portion provided on the upper end side of the neck portion and to which a cap that closes the upper opening end is attached are integrally formed. A base coat layer made of the first resin layer containing a curable resin is formed, and a design layer made of the second resin layer formed in an arbitrary shape is formed, leaving an exposed portion of the base coat layer. It may be formed over the entire circumference of the cylindrical portion.

A method for manufacturing a painted aluminum container of the present invention is a method for manufacturing a painted aluminum container according to each of the above items, comprising a first resin layer forming step of forming the first resin layer on the surface of the container body; and a second resin layer forming step of forming the second resin layer overlying the first resin layer such that a part of the first resin layer is exposed, and the second resin layer forming step is characterized in that when a plurality of resin films are formed by stacking a resin liquid containing a photopolymerizable material from a droplet discharge device, the resin films adjacent to each other are photopolymerized.

Further, in the present invention, the first resin layer forming step forms the first resin layer from a material containing a photopolymerizable material, and the second resin layer forming step removes at least the lowermost resin film from the You may photopolymerize with respect to a 1st resin layer.

Further, in the present invention, the step of forming the second resin layer includes, after discharging the resin liquid by the droplet discharge device, irradiating ultraviolet rays to polymerize the first resin layer and the lowermost resin film. You may let

Further, in the present invention, the resin liquid may contain a polymerizable unsaturated resin monomer or oligomer.

Further, in the present invention, the container body includes a bottom portion, a cylindrical portion extending cylindrically from the outer peripheral edge of the bottom portion, a shoulder portion whose diameter decreases upward from the upper end of the cylindrical portion, and further from the shoulder portion. A neck portion extending upward and a cap attachment portion provided on the upper end side of the neck portion and to which a cap that closes the upper opening end is attached are integrally formed, and the first resin layer forming step includes: A step of applying a base coating to the entire surface of the cylindrical portion and baking it to form a base coating film layer that is the first resin layer, and the step of forming the second resin layer is performed by the liquid droplet ejection device. In the step of forming a design layer composed of the second resin layer in which a plurality of the resin films are sequentially laminated by ejecting an ultraviolet curable paint that is a resin liquid so that a part of the base coating layer is exposed. In the second resin layer forming step, each time the upper resin film is formed over one resin film, ultraviolet light is irradiated to polymerize the adjacent resin films with ultraviolet light, or After laminating all the resin films constituting the design layer, the entire resin film may be subjected to ultraviolet polymerization.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to maintain high productivity even when a printing method using droplet ejection is used, and it is possible to provide a painted aluminum container with excellent design, and a method for manufacturing the painted aluminum container. can.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external perspective view which shows the painted aluminum container of 1st Embodiment of this invention. FIG. 2 is an enlarged cross-sectional view of a main portion of the coated aluminum container of FIG. 1; It is a principal part expanded sectional view of the painted aluminum container of 2nd Embodiment. It is a principal part expanded sectional view of the painted aluminum container of 3rd Embodiment. It is a principal part expanded sectional view of the painted aluminum container of 4th Embodiment. It is a principal part expanded sectional view of the painted aluminum container of 5th Embodiment. It is an external appearance perspective view of the painted aluminum container of 6th Embodiment. FIG. 3 is a schematic diagram showing an example of an inkjet printer (liquid droplet ejection device) used in the second resin layer forming step;

DESCRIPTION OF THE PREFERRED EMBODIMENTS A coated aluminum container as an embodiment to which the present invention is applied and a method for manufacturing the coated aluminum container will be described below with reference to the drawings. It should be noted that the embodiments shown below are specifically described for better understanding of the gist of the invention, and do not limit the invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make it easier to understand the features of the present invention, there are cases where the main parts are enlarged for convenience, and the dimensional ratio of each component is the same as the actual one. not necessarily.

(Painted aluminum container: first embodiment)
A coated aluminum container according to a first embodiment of the present invention will be described.
FIG. 1 is an external perspective view showing a painted aluminum container according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the main part of the coated aluminum container of FIG.
The coated aluminum container 10 of the present embodiment includes an aluminum container body 11, a first resin layer 12 formed on the container body 11, and a second resin layer 12 formed on a part of the first resin layer 12. layer 13;
The container body 11 has a bottomed cylindrical shape with one side open, and is formed by, for example, drawing and ironing an aluminum alloy plate.

The first resin layer 12 is a primer coating film that protects the surface of the container body 11, and may be, for example, a transparent size coat or a colored base coat such as white.

The interface between the first resin layer 12 and the second resin layer 13 formed over the first resin layer 12 is bonded by photopolymerization such as photoradical polymerization or photocationic polymerization. This prevents the second resin layer 13 from peeling off from the first resin layer 12 even if an external stress is applied to the second resin layer 13 .

The interface between the first resin layer 12 and the second resin layer 13 formed over the first resin layer 12 is bonded by photopolymerization such as photoradical polymerization or photocationic polymerization. This prevents the second resin layer 13 from peeling off from the first resin layer 12 even if an external stress is applied to the second resin layer 13 .

The first resin layer 12 before forming the second resin layer 13 (before polymerization) includes a resin base material containing a thermosetting resin and a photopolymerizable material that is photopolymerized with respect to the second resin layer 13 . I'm in.
As the resin base material constituting the first resin layer 12, for example, a hardened coating film containing a polyester resin and an amino resin as essential components may be used. In addition, such resins may further contain epoxy resins, isocyanate resins, and the like. In addition, it may be obtained by curing a coating film containing epoxy resin as an essential component and at least one of urea-based resin and phenolic resin. Moreover, what is necessary is just to harden the coating film which has an acrylic resin as an essential component.

Acid components constituting the polyester resin described above include, for example, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, hexahydroisophthalic acid, hexahydroterephthalic acid, succinic acid, fumaric acid, One or more dibasic acids selected from adipic acid, sebacic acid, maleic anhydride, etc. and lower alkyl esters of these acids are mainly used, and if necessary, benzoic acid, crotonic acid, p-tert-butylbenzoic acid. A monobasic acid such as an acid, a polybasic acid having a valence of 3 or more such as trimellitic anhydride, methylcyclohexene tricarboxylic acid, and pyromellitic anhydride may be used in combination.

Examples of alcohol components constituting the polyester resin described above include ethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 2-methyl 1,3-propanediol, Dihydric alcohols such as 3-methylpentanediol, 1,4-hexanediol, 1,6-hexanediol, and 1,4-dimethylolcyclohexane may be used. Furthermore, trihydric or higher polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane and pentaerythritol can be used in combination as necessary. These alcohol components can be used alone or in combination of two or more.

The amino resin described above is not particularly limited, but for example, a methylolated amino resin composed of an amino component such as melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, and dicyandiamide and a methylol component may be used. can be done. Compounds that react with such amino moieties to form methylol moieties include, for example, formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, and the like.

In addition, the resin base material constituting the first resin layer 12 is the methylol component of the above-mentioned methylolated amino resin, from the viewpoint of improving the drawability, adhesion, scratch resistance, hot water resistance, and gloss of the first resin layer 12. can be used an alkoxylated amino resin in which at least a part of is etherified with a monohydric alcohol. In particular, benzoguanamine is preferred as the amino component, and at least part of the methylol component is preferably etherified with butanol. Specifically, a butoxylated benzoguanamine resin is particularly preferred.

The isocyanate compounds described above are not particularly limited, but for example, aromatic isocyanate compounds such as tolylene diisocyanate (TDI), phenylene diisocyanate, diphenylmethane diisocyanate (MDI), dimethylbiphenylene diisocyanate, dimethoxybiphenylene diisocyanate, dichlorobiphenylene diisocyanate, and naphthalene diisocyanate. , tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate (HDI), cyclohexyl diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate. group isocyanate compounds. Dimers and trimers of the isocyanate compounds described above can also be used. Aliphatic isocyanate compounds are preferable from the viewpoint of less yellowing than aromatic isocyanate compounds.

The first resin layer 12 before polymerization contains a photopolymerizable material to be photopolymerized with respect to the second resin layer 13 together with the resin base material described above. Photopolymerizable materials include photopolymerizable oligomers or photopolymerizable monomers that undergo photoradical polymerization or photocationic polymerization. Examples include various oligomers or polymers including (meth)acrylates. By using these, when the second resin layer 13 is formed over the first resin layer 12, the interface between the first resin layer 12 and the second resin layer 13 can be firmly bonded by photopolymerization. .

A compound having an acryloyl group can be used as the photoradical polymerizable material. Examples of oligomers that can be used include acrylic acrylate, urethane acrylate, polyester acrylate, epoxy acrylate, and glycidyl acrylate. A multifunctional acrylate having a branched structure can also be used. Compounds having a glycidyl group or an oxetane group can also be used as the photo-cationically polymerizable material, and oligomers such as alicyclic epoxy, glycidyl type epoxy, and oxetane compounds can also be used.

For example, the first resin layer 12 before polymerization contains 1% by mass or more and 10% by mass of a compound having an acryloyl group or a glycidyl group with respect to the entire solid content of the first resin layer 12, for example, the resin base material described above. It should be included within the following range.

Further, in the first resin layer 12, solids such as acrylic resin beads, fumed silica, diatomaceous earth, etc. are used to form fine unevenness on the surface of the second resin layer 13 side, and the first resin layer 12 and the second resin are separated. It is also preferable to adopt a configuration that enhances adhesion to the layer 13 . By forming minute unevenness on the first resin layer 12 using such a solid material, it is possible to suppress movement (positional deviation) when the discharged liquid lands on the second resin layer 13 during film formation.

In the first resin layer 12, the surface of a solid such as acrylic resin beads, fumed silica, or diatomaceous earth is further treated with a material having a photopolymerizable functional group such as methacrylsilyl or acrylsilyl. can also be used.

In addition, the first resin layer 12 contains either hydrophilic fumed silica having a specific surface area of 20 to 410 m ² /g as measured by the BET method or hydrophobic fumed silica whose surface is modified with an organic compound. The above can also be contained in the range of 0.1 to 5% by mass.

It is also preferable that the first resin layer 12 further contains a lubricant. By containing such a lubricant, it is possible to effectively prevent the first resin layer 12 from being scratched during the processing and transportation of the container body 11 . Lubricants are not particularly limited, but examples include plant waxes, animal waxes, mineral waxes, petroleum waxes, fatty acid ester waxes, silicone waxes, fluorine waxes, polyolefin waxes, and the like. be done. Also, two or more of these waxes can be used in combination.

Examples of the plant-based waxes mentioned above include carnauba wax, cotton wax, and Japan wax. Animal waxes include lanolin wax, gay wax, and beeswax, and mineral waxes include ozokerite, montan wax, and the like.

Examples of the petroleum wax include paraffin wax, microcrystalline wax, and petrolatum. Examples of fatty acid ester wax include esters of fatty acid sucrose ester polyglycerin ether and fatty acid.

Examples of the fluorine-based wax include polytetrafluoroethylene wax, and examples of the polyolefin-based wax include polyethylene wax and oxidized polyethylene wax.

The amount of the lubricant that constitutes the first resin layer 12 is, for example, 0.1 to 30 parts by mass with respect to 100 parts by mass of the above-described resin base material, which is the base resin of the first resin layer 12. is preferred, and 0.5 to 10 parts by mass is more preferred.

Such a first resin layer 12 can further contain a filler. The filler is not particularly limited, but titanium oxide, aluminum paste, pearl powder, high-brightness inorganic compounds, etc. can be used, for example, in order to hide the metallic color of the container body 11 and enhance the design.

For example, an undercoat paint containing titanium oxide as a filler is called white, and acts as a primer that enhances bonding to the container body 11, and forms a white first resin layer 12 that hides the metallic color of the container body 11, It plays a role of a colored layer that enhances the design of the second resin layer 13 formed over the first resin layer 12 .

The first resin layer 12 configured as described above may be formed, for example, so as to have a film thickness of approximately 0.5 μm to 15 μm. The first resin layer 12 is formed by, for example, coating the surface of the container body 11 with the above-described resin base material and a resin made of a photopolymerizable material using a roll coater, and thermally curing the resin base material at, for example, 160°C to 240°C. formed by After such thermal curing, the polymerization reaction points of the photopolymerizable material are maintained.

Also, the first resin layer 12 is preferably formed so that the surface tension at 20° C. is 22 mN/m or more and 72 N/m or less. By setting the surface tension of the first resin layer 12 to 22 mN/m or more, when the second resin layer 13 is formed over the first resin layer 12, the resin film 14 formed using a droplet discharge device is It is possible to prevent the surface of the first resin layer 12 from being repelled, and to increase the thickness of the second resin layer 13 in an intended portion and shape to form a three-dimensional shape.

The second resin layer 13 is entirely composed of a polymerizable compound, or a resin film 14 composed of a resin containing a polymerizable compound in part, for example, a photo-radical polymerizable ultraviolet curable resin, is formed by a droplet discharge device, For example, it is formed on the surface of the first resin layer 12 using an inkjet printer, and each layer is sequentially laminated while being cured by photopolymerization reaction by UV irradiation, or a plurality of laminated resin films 14, 14 ... are photopolymerized. It is formed by integrating by

When each layer is irradiated with UV light during the formation of the resin film 14, if the reaction is suppressed at a certain rate by lowering the irradiation intensity of the UV light or shortening the irradiation time, the next layer is formed. The second resin layer 13 can be formed by performing a photopolymerization reaction on the resin film 14 and integrating all the laminated resin films 14 .

In the process of forming the second resin layer 13, the photopolymerizable material contained in the lowermost resin film 14 and the photopolymerizable material contained in the first resin layer 12 are photopolymerized to form the second resin layer. 13 is firmly bonded to the first resin layer 12 .

The resin film 14 (resin liquid ejected from the droplet ejection device) before polymerization 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 acrylic resin (including methacrylic resin), epoxy resin, urethane resin, and vinyl resin (including vinyl chloride resin, polyvinyl alcohol resin, and vinyl acetate resin). , polyester resins, polyester amino resins, silicone resins, and polyolefin resins.

More specifically, as the photopolymerizable material contained in the resin film 14 before polymerization, monofunctional to oligofunctional and prepolymers can be used as acrylic monomers, methacrylic monomers, and vinyl compounds. In addition, as photopolymerizable oligomers, for example, epoxy acrylates, aliphatic and aromatic urethane acrylates, polyester acrylates, acrylic oligomers, and the like can be used.

In particular, the resin film 14 is coated with a resin paint containing 0.1% to 2% of a polyester-based resin such as polyester acrylate (ultraviolet polymerizable oligomer) as a photopolymerizable material having good adhesion to the first resin layer 12. If formed, it can be photopolymerized with the photopolymerizable material contained in the first resin layer 12 before polymerization.

In addition, by forming the second resin layer 13 by integrating a plurality of resin films 14 by photopolymerization using a photopolymerizable material, for example, shrinkage due to solvent evaporation during drying such as water-based paint or oil-based paint can be prevented. can do.

The resin film 14 before polymerization when forming the second resin layer 13 is formed by using a water-based paint obtained by dissolving the above-described resin in an aqueous solvent or an oil-based paint obtained by dissolving the above-described resin in an organic solvent. For example, it can be formed by discharging from an ink jet head of an ink jet printer toward the first resin layer 12 .

Also, the resin film 14 can be formed by ejecting a resin paint containing a polymerizable unsaturated compound from an inkjet head. If an ultraviolet curable resin coating containing a polymerizable unsaturated compound is used as the resin film 14, it is possible to prevent the coating from shrinking due to evaporation of the solvent during drying, unlike water-based or oil-based coatings.

As the polymerizable unsaturated compound, monofunctional to oligofunctional and prepolymers can be used as acrylic monomers, methacrylic monomers and vinyl compounds. In addition, epoxy acrylates, aliphatic and aromatic urethane acrylates, polyester acrylates, acrylic oligomers, and the like can be used as polymerizable oligomers.

In particular, if the resin film 14 is formed with a resin coating containing 0.1% to 2% of a polymerizable oligomer of a polyester resin that is compatible with the first resin layer 12 in terms of adhesion, the first resin layer 12 can be A strongly fixed second resin layer 13 can be formed.

Such a second resin layer 13 may be formed to have any design, such as letters or figures. In this embodiment, the second resin layer 13 is designed with Chinese characters formed so as to protrude from the first resin layer 12 .

The second resin layer 13 of the present embodiment has, for example, a substantially semicircular cross section and a smooth curved surface. By making the surface of the second resin layer 13 a smooth curved surface, irregular reflection of light rays is suppressed. Therefore, if the second resin layer 13 is made to have a color tone impermeable to visible light, a metallic appearance can be obtained. Further, if the second resin layer 13 has a transparent color tone that transmits visible light, the lens effect allows the design formed by the second resin layer 13 to stand out three-dimensionally.

The protrusion thickness of the second resin layer 13 protruding from the surface of the first resin layer 12 may be, for example, 0.03 mm or more and 1 mm or less. If the protrusion thickness of the second resin layer 13 is less than 0.03 mm, there is a concern that the three-dimensional effect of the second resin layer 13 cannot be obtained. Moreover, if the thickness of the protrusion of the second resin layer 13 exceeds 1 mm, the amount of protrusion from the first resin layer 12 becomes too large, so there is a concern that the second resin layer 13 may partially peel off.

The second resin layer 13 is formed so as to partially cover the first resin layer 12 . That is, part of the first resin layer 12 (the part where the second resin layer 13 is not formed) is exposed to the outside. Therefore, the exposed portion of the first resin layer 12 functions as a protective film for the container body 11 .

According to the coated aluminum container 10 of the present embodiment configured as described above, compared with a conventional coated aluminum container designed with a flat coating film having poor three-dimensionality, the plurality of resin films 14 The second resin layer 13 formed so as to protrude from the first resin layer 12 obtained by laminating and integrating is realized a painted aluminum container 10 with a three-dimensional design and high designability. can do.

Further, the first resin layer 12 and the second resin layer 13 are made of a resin containing a photopolymerizable material, and the interface between the first resin layer 12 and the second resin layer 13 is photopolymerized, for example, by ultraviolet polymerization, The first resin layer 12 and the second resin layer 13 can be strongly bonded. As a result, even if the second resin layer 13 having a three-dimensional thickness is formed on the first resin layer 12, there is no concern that the second resin layer 13 will separate from the first resin layer 12 due to external stress or the like. A highly durable painted aluminum container 10 can be achieved.

Then, according to the coated aluminum container 10 of the present embodiment, the exposed portions of the second resin layer 13 and the first resin layer 12 are covered by configuring a portion of the first resin layer 12 to be exposed to the outside. Formation of a protective film becomes unnecessary, and even when the container body 11 is coated by an inkjet printing method that takes longer time to print than offset printing, the printing time of the protective film can be omitted, and the coating can be performed. A decrease in productivity of the aluminum container 10 can be prevented.

Further, in the coated aluminum container 10 of the present embodiment, when forming the resin film 14 constituting the second resin layer 13 using a resin paint containing a polymerizable unsaturated compound, after laminating a plurality of resin films 14 Since the second resin layer 13 can be formed by integrating these by polymerization, even if the protruding thickness of the second resin layer 13 is a three-dimensional thick coating such as 0.03 mm or more and 1 mm or less, physical A design print having excellent strength and durability can be formed on the container body 11. - 特許庁

(Painted aluminum container: Second embodiment)
A coated aluminum container according to a second embodiment of the present invention will be described.
FIG. 3 is an enlarged cross-sectional view of a main part of a coated aluminum container according to a second embodiment.
In addition, the same number is attached|subjected to the structure similar to 1st Embodiment, and the overlapping description is abbreviate|omitted.
The coated aluminum container 20 of this embodiment comprises a container body 11, a first resin layer 12 formed on the container body 11, and a second resin layer 23 formed on a part of the first resin layer 12. have

The second resin layer 23 is formed by integrating a plurality of resin films 24, 24 containing a photopolymerizable material by photopolymerization. The resin film 24 of the present embodiment is formed so that the width gradually narrows from the lower resin film 24 in contact with the first resin layer 12 toward the upper resin film 24 . As a result, a plurality of steps are formed on the outer surface of the second resin layer 23, and the cross-sectional shape thereof is substantially trapezoidal.

According to the coated aluminum container 20 of the present embodiment, the second resin layer 23 protruding from the surface of the first resin layer 12 has a cross section of, for example, a substantially trapezoidal shape, and the inclined portions on both sides have a plurality of steps. is formed. As a result, when light hits the second resin layer 23, the light is irregularly reflected by the plurality of steps, and a mud-like appearance can be obtained. By coloring the second resin layer 23 in an arbitrary color tone with a pigment, characters in an arbitrary color tone with reduced luster can be expressed as if they stand out three-dimensionally.

In addition, in the present embodiment, since the upper edge portion of the second resin layer 23 is directly exposed to the outside, the outline of the second resin layer 23 can be represented sharper than when covered with a protective film or the like. can be done.

Also in the coated aluminum container 20 of the second embodiment, the first resin layer 12 is formed of a material containing a photopolymerizable material, and the interface between the first resin layer 12 and the second resin layer 23 is photopolymerized. The first resin layer 12 and the second resin layer 23 can be strongly bonded by making the first resin layer 12 and the second resin layer 23 . As a result, even if the second resin layer 23 having a three-dimensional thickness is formed on the first resin layer 12, there is a concern that the second resin layer 23 may separate from the first resin layer 12 due to external stress or the like. It is possible to realize a coated aluminum container 20 having high durability.

In addition, by exposing a part of the first resin layer 12 to the outside without covering it with the second resin layer 23, a protective film covering the exposed parts of the second resin layer 13 and the first resin layer 12 is formed. becomes unnecessary, and even when the container body 11 is coated by an inkjet printing method that takes more time to print than offset printing, the printing time of the protective film can be omitted, and the coated aluminum container 10 can prevent a decrease in productivity.

(Painted Aluminum Container: Third Embodiment)
A coated aluminum container according to a third embodiment of the present invention will be described.
FIG. 4 is an enlarged cross-sectional view of a main part of a painted aluminum container according to a third embodiment.
In addition, the same number is attached|subjected to the structure similar to 1st Embodiment, and the overlapping description is abbreviate|omitted.
The coated aluminum container 30 of this embodiment includes a container body 11, a first resin layer 12 formed on the container body 11, and a plurality of resin films 14 formed on a part of the first resin layer 12. , 14 integrated by photopolymerization, and a printed layer 31 formed between the container body 11 and the first resin layer 12 .

The printed layer 31 is a layer in which an arbitrary pattern or the like is printed on the surface of the container body 11, and can be formed by offset printing, screen printing, or the like, in addition to inkjet printing or the like.

The second resin layer 13 may be formed at a position overlapping the print layer 31 . Then, for example, if the second resin layer 13 is formed in a colorless and transparent color tone that transmits visible light, and has a smooth surface and a semicircular cross-section, as in the first embodiment, the lens effect of the second resin layer 13 can be obtained. As a result, when viewed from the outside, the pattern of the printed layer 31 below the second resin layer 13 appears enlarged.

Thus, in the coated aluminum container 30 of the present embodiment, the printed layer 31 formed on the surface of the container body 11 decorates the second resin layer 13 itself formed so as to protrude from the first resin layer 12. Therefore, it is possible to realize the painted aluminum container 30 with a three-dimensional design that is even more excellent in design.

In addition, by exposing a part of the first resin layer 12 to the outside without covering it with the second resin layer 13, a protective film covering the exposed parts of the second resin layer 13 and the first resin layer 12 is formed. becomes unnecessary, and even when the container body 11 is coated by an inkjet printing method that takes more time to print than offset printing, the printing time of the protective film can be omitted, and the coated aluminum container 10 can prevent a decrease in productivity.

(Painted Aluminum Container: Fourth Embodiment)
A painted aluminum container according to a fourth embodiment of the present invention will be described.
FIG. 5 is an enlarged cross-sectional view of a main part of a painted aluminum container according to a fourth embodiment.
In addition, the same number is attached|subjected to the structure similar to 1st Embodiment, and the overlapping description is abbreviate|omitted.
The coated aluminum container 40 of this embodiment includes a container body 11, a first resin layer 12 formed on the container body 11, and a plurality of resin films 14 formed on a part of the first resin layer 12. , 14 integrated by photopolymerization, and a printed layer 41 formed between the first resin layer 12 and the second resin layer 13 .

The printed layer 41 is a layer in which an arbitrary pattern or the like is printed on the surface of the first resin layer 12, and can be formed by offset printing, screen printing, or the like other than inkjet printing.

The second resin layer 13 may be formed at a position overlapping the print layer 41 . Then, for example, if the second resin layer 13 is formed in a colorless and transparent color tone that transmits visible light, and has a smooth surface and a semicircular cross-section, as in the first embodiment, the lens effect of the second resin layer 13 can be obtained. As a result, when viewed from the outside, the pattern of the printed layer 41 under the second resin layer 13 can be seen enlarged.

Thus, in the coated aluminum container 40 of the present embodiment, the printed layer 41 formed on the surface of the first resin layer 12 allows the second resin layer 13 itself formed to protrude from the first resin layer 12 to be Since it can be decorated, it is possible to realize a painted aluminum container 30 with a three-dimensional design that is even more excellent in design.

In addition, by exposing a part of the first resin layer 12 to the outside without covering it with the second resin layer 13, a protective film covering the exposed parts of the second resin layer 13 and the first resin layer 12 is formed. becomes unnecessary, and even when the container body 11 is coated by an inkjet printing method that takes more time to print than offset printing, the printing time of the protective film can be omitted, and the coated aluminum container 10 can prevent a decrease in productivity.

(Painted Aluminum Container: Fifth Embodiment)
A coated aluminum container according to a fifth embodiment of the present invention will be described.
FIG. 6 is an enlarged cross-sectional view of a main portion of a coated aluminum container according to a fifth embodiment.
In addition, the same number is attached|subjected to the structure similar to 1st Embodiment, and the overlapping description is abbreviate|omitted.
The coated aluminum container 50 of this embodiment includes a container body 11, a first resin layer 12 formed on the container body 11, and a plurality of resin films 14 formed on a part of the first resin layer 12. , 14 are integrated by photopolymerization.

Fine fillers 56 are mixed and dispersed in the first resin layer 12 of the present embodiment. The filler 56 may be, for example, micro-sized or nano-sized inorganic powder or organic powder. By mixing the filler 56 into the first resin layer 12, it is possible to improve visual effects such as enhancing the appearance of the first resin layer 12 with a muddiness.

(Painted Aluminum Container: Sixth Embodiment)
A coated aluminum container according to a sixth embodiment of the present invention will be described.
FIG. 7 is an external perspective view of a painted aluminum container according to a sixth embodiment.
In addition, the same number is attached|subjected to the structure similar to 1st Embodiment, and the overlapping description is abbreviate|omitted.
The coated aluminum container 60 of the present embodiment is a bottle-shaped aluminum bottle can intended for containing alcoholic beverages, for example, and has a container body 61 .

The container body 61 includes a bottom portion 62, a cylindrical portion 63 extending cylindrically upward from the outer peripheral edge of the bottom portion 62, a shoulder portion 64 whose diameter decreases upward from the upper end of the cylindrical portion 63, and the shoulder portion 64. A neck portion 65 extending further upward from the portion 64 and a cap mounting portion 66 provided on the upper end side of the neck portion 65 and covered with a cap C for covering the upper opening end 65a are integrally formed of aluminum. It becomes

The cap mounting portion 66 may be formed with a screw or a flange according to the shape of the cap C. As shown in FIG. In this embodiment, a male threaded portion 66b that is screwed into a female thread (not shown) formed on the inner peripheral surface of the cap C is formed.

In order to manufacture such a container body 61, first, in a cupping press process using a cupping press machine, a metal plate such as aluminum or an aluminum alloy is punched into a disk shape and drawn to form a shallow cup-shaped material. manufacture. Next, the cup-shaped material is subjected to redrawing and ironing in a DI pressing process using a DI press machine, and stretched in the can axial direction, whereby the container body 61, which is a bottle-shaped bottomed cylindrical body, can be formed. .

A base coat layer (first resin layer) 72 containing a thermosetting resin is formed on the cylindrical portion 63 of the container body 61 so as to cover the entire surface. The undercoating film layer 72 before forming the design layer (second resin layer) 73 (before polymerization) is exposed to light with respect to the design layer 73 formed so as to partially expose the undercoating film layer 72 . It is preferred that the mutual interfaces are bonded by polymerisation, for example photoradical polymerisation or photocationic polymerisation. As a result, even if external stress is applied to the design layer 73 , it is possible to prevent the design layer 73 from peeling off from the undercoat layer 72 .

The design layer (second resin layer) 73 is entirely composed of a polymerizable compound, or is a resin film (see FIG. 2 etc. ) is formed on the surface of the base coating film layer 72 using a droplet discharge device, and each layer is sequentially laminated while being cured by photopolymerization reaction by UV irradiation, or a plurality of laminated resin films are collectively formed. It is formed by integrating by a photopolymerization reaction.

The design layer (second resin layer) 73 of the present embodiment is formed, for example, in the entire circumferential direction of the cylindrical portion 63 of the container body 61 so as to emulate an arbitrary design, and is solidly painted in an elliptical shape near the center. A labeled area is formed. The design layer 73 of the present embodiment has a design representing, for example, wine as a contained object.

According to the coated aluminum container 60 of the present embodiment, a plurality of resin films are laminated and integrated with the container body 61 formed in the same shape as a conventional glass bottle. The design layer 73 formed so as to protrude from the base coating film layer 72 makes it possible to realize the bottle-shaped painted aluminum container 60 with a three-dimensional design and high designability.

By forming the design layer 73 over the entire circumference of the cylindrical portion 63 so as to protrude from the base coating film layer 72, for example, a beverage bottle can provided with the coated aluminum container 60 can be used as a storage box. Even if vibration is applied when a plurality of bottle cans are conveyed side by side, the design layer (second resin layer) 73 of adjacent beverage bottle cans will only come into contact with each other and rub against each other, and the underlying coating film layer 72 will rub against each other. there is nothing As a result, the base coating film layer 72 that protects the container body 61 does not peel off, and corrosion of the container body 61 can be prevented.

(Manufacturing method of painted aluminum container)
A method for manufacturing a painted aluminum container according to one embodiment of the present invention will be described.
For example, when manufacturing the coated aluminum container 10 of the first embodiment described above, the container body 11 is prepared by drawing and ironing an aluminum alloy plate.

As the container body 11, for example, as shown in FIG. A shoulder portion 64 with a reduced diameter, a neck portion 65 extending further upward from the shoulder portion 64, and a cap attachment portion 66 provided on the upper end side of the neck portion 65 and to which a cap C is attached to close the upper opening end 65a. and can be bottle cans integrally formed of aluminum.

Then, the first resin layer (base coat layer) 12 is formed on the surface of, for example, the cylindrical portion 63 of the container body 11 as described above (first resin layer forming step).
Materials for forming the first resin layer 12 include, for example, a resin base material made of a thermosetting resin, and a photopolymerizable material that is photopolymerized with respect to the second resin layer 13 in the next step. A material containing a curing (polymerizing) UV curable coating may be used. Examples of UV-curable photopolymerizable materials include photoradical polymerizable materials and photocationically polymerizable materials. Examples include various oligomers or polymers including (meth)acrylates. By using these, when the second resin layer 13 is formed over the first resin layer 12, the interface between the first resin layer 12 and the second resin layer 13 can be firmly bonded by photopolymerization. .

For forming the first resin layer 12, for example, using a roll coater, a coating liquid containing the material for forming the first resin layer 12 is applied to the surface of the container body 11 so that the film thickness is, for example, about 3 μm to 10 μm. Then, the thermosetting resin contained in the forming material of the first resin layer 12 is thermally cured (baked) at 160° C. to 240° C., for example. After such thermal curing, the polymerization reaction points of the photopolymerizable material are maintained.

Next, a plurality of resin films 14 are laminated on the container main body 11 having the first resin layer 12 formed thereon by using a droplet discharge device such as an inkjet printer, and integrated by polymerization by ultraviolet irradiation to form a second resin layer. 13 is formed (second resin layer forming step). In this second resin layer forming step, after the resin liquid is discharged onto the surface of the first resin layer 12 to form the resin film 14 before polymerization, the first resin layer 12 is irradiated with ultraviolet rays, for example. A second resin layer 13 is formed that is bonded to the surface by photopolymerization.

When forming the second resin layer 13, an inkjet printer (droplet ejection device) having an inkjet head capable of ejecting a resin liquid for forming the resin film 14 on the curved surface of metal may be used.

As the photopolymerizable material used for the resin liquid for forming the resin film 14 constituting the second resin layer 13, for example, monofunctional to oligofunctional and prepolymers may be used as acrylic monomers, methacrylic monomers, and vinyl compounds. can be done. In addition, epoxy acrylates, aliphatic and aromatic urethane acrylates, polyester acrylates, acrylic oligomers, and the like can be used as polymerizable oligomers.

In this embodiment, as shown in FIG. 8, an inkjet printer P (droplet ejection device) having, for example, six inkjet heads is used, and productivity is improved by limiting the number of inkjet heads to be used. . For example, among C, M, Y, and K heads used for color printing, only the M (magenta) head is used, and two heads V are assigned to laminate a transparent resin film (varnish). there is

Then, while rotating the container body 11 on which the first resin layer 12 is formed, the resin liquid containing the photopolymerizable material is discharged from each head to form the resin film 14 before polymerization. Then, for example, by irradiating ultraviolet rays from an ultraviolet irradiation unit UV formed at a position facing each head, the resin film 14 before polymerization ejected from each head is photopolymerized, and the resin film 14 in the lowermost layer is are bonded to the first resin layer 12, and the upper resin film 14 is bonded to the lower resin film 14 by photopolymerization. As a result, the second resin layer 13 firmly bonded to the first resin layer 12 by photopolymerization is formed.

In forming the second resin layer 13, as described above, the ultraviolet irradiation unit UV is arranged corresponding to each ink jet head. Alternatively, after laminating all the resin films 14 before polymerization, polymerization may be performed all at once.

In any of these methods, the lowermost resin film 14 and the first resin layer 12 are photopolymerized to form the second resin layer 13 firmly bonded to the first resin layer 12 . can be done. For example, a photopolymerizable material that can be photopolymerized with respect to the photopolymerizable material contained in the first resin layer 12, for example, a resin containing a polymerizable oligomer of a polyester resin in the range of 1 to 10% by mass. The second resin layer 13 can be formed by photopolymerizing the first resin layer 12 by ejecting the liquid to form the lowermost resin film 14 and irradiating it with ultraviolet rays.

In addition, by reducing the number of colors without performing multicolor coating as in this embodiment, the time to form the second resin layer 13 is shortened, and the productivity of the coated aluminum container 10 is improved. can be done. In addition, by using two heads for laminating a transparent resin film (varnish) for increasing the thickness of the second resin layer 13 and increasing the discharge amount of the resin liquid, a thick three-dimensional effect can be achieved. The second resin layer 13 can be formed in a short time, and the productivity of the coated aluminum container 10 can be improved.

In the second resin layer forming step, a resin paint containing a polymerizable unsaturated compound can be used as the resin liquid for forming the resin film 14 . For example, an ultraviolet curable resin coating containing a polymerizable unsaturated compound is ejected from an inkjet head as a resin liquid to laminate a plurality of resin films 14, and when irradiated with ultraviolet rays, the plurality of resin films 14 do not shrink with each other. A second resin layer 13 that is polymerized and integrated can be formed.

As shown in FIG. 8, the second resin layer 13 formed in this manner is, for example, a design layer (a design layer) formed in the entire circumferential direction of the cylindrical portion 63 of the container body 61 so as to have an arbitrary design. The second resin layer) 73 may be sufficient, and the design layer 73 formed to protrude from the base coating film layer 72 allows the bottle-shaped painted aluminum container 60 with a three-dimensional design and high design property to be manufactured. can be manufactured.

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 implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, as well as the scope of the invention described in the claims and its equivalents.

For example, the container body of the embodiment may be a container body that is open on one side before being filled with the contents, or a container body that is filled with the contents and the can lid is seamed (filled can). may Further, instead of the aluminum container body, an aluminum cup-shaped container body having a cylindrical or tapered body portion may be used.

DESCRIPTION OF SYMBOLS 10... Painted aluminum container 11... Container main body 12... First resin layer (base coat layer)
13... Second resin layer (design layer)
14... resin film

Claims (13)

a container body made of aluminum;
a first resin layer formed to cover the surface of the container body;
a second resin layer formed on part of the surface of the first resin layer;
The second resin layer is formed by integrating a plurality of resin films containing a photopolymerizable material by photopolymerization,
A coated aluminum container, wherein a part of the first resin layer is exposed to the outside. 2. The method according to claim 1, wherein the first resin layer contains a thermosetting resin and a photopolymerizable material, and at least the resin film of the lowermost layer and the first resin layer are bonded by photopolymerization. Painted aluminum container as described. 3. The painted aluminum container according to claim 1, wherein the photopolymerizable material is a photopolymerizable oligomer or photopolymerizable monomer that undergoes photoradical polymerization or photocationic polymerization. The painted aluminum container according to any one of claims 1 to 3, wherein the second resin layer contains a visible light transmissive resin. At least one of between the container body and the first resin layer, between the first resin layer and the second resin layer, or between the resin films of the second resin layer 5. The painted aluminum container according to claim 4, further comprising a printed layer. The painted aluminum container according to any one of claims 1 to 5, wherein a filler is further dispersed in the first resin layer. The painted aluminum container according to any one of claims 1 to 6, wherein the thickness of the second resin layer is 0.03 mm or more and 1 mm or less. The container body includes a bottom portion, a cylindrical portion extending cylindrically from the outer peripheral edge of the bottom portion, a shoulder portion whose diameter decreases upward from the upper end of the cylindrical portion, and a neck portion extending upward from the shoulder portion. and a cap mounting portion provided on the upper end side of the neck portion and to which a cap that closes the upper opening end is attached, are integrally formed,
An undercoat layer made of the first resin layer containing a thermosetting resin is formed on the entire surface of the cylindrical portion, and a design layer made of the second resin layer formed in an arbitrary shape is the undercoat. 8. The painted aluminum container according to any one of claims 1 to 7, characterized in that it is formed over the entire circumference of the cylindrical portion, leaving exposed portions of the layer. A method for manufacturing a painted aluminum container according to any one of claims 1 to 8,
a first resin layer forming step of forming the first resin layer on the surface of the container body;
a second resin layer forming step of forming the second resin layer over the first resin layer such that a part of the first resin layer is exposed;
In the second resin layer forming step, when a plurality of the resin films are formed by stacking a resin liquid containing a photopolymerizable material from a droplet discharge device, the resin films adjacent to each other are photopolymerized. A method for manufacturing a painted aluminum container, characterized by: The first resin layer forming step includes forming the first resin layer with a material containing a photopolymerizable material,
10. The method for manufacturing a painted aluminum container according to claim 9, wherein in the second resin layer forming step, at least the lowermost resin film is photopolymerized with respect to the first resin layer. In the second resin layer forming step, after the resin liquid is discharged by the droplet discharge device, ultraviolet rays are irradiated to polymerize the first resin layer and the lowermost resin film. A method for producing a painted aluminum container according to claim 10. 12. The method for manufacturing a painted aluminum container according to any one of claims 9 to 11, wherein the resin liquid contains a polymerizable unsaturated resin monomer or oligomer. The container body includes a bottom portion, a cylindrical portion extending cylindrically from the outer peripheral edge of the bottom portion, a shoulder portion whose diameter decreases upward from the upper end of the cylindrical portion, and a neck portion extending upward from the shoulder portion. and a cap mounting portion provided on the upper end side of the neck portion and to which a cap that closes the upper opening end is attached, are integrally formed,
The first resin layer forming step is a step of applying a base paint to the entire surface of the cylindrical portion and baking it to form a base coating film layer as the first resin layer,
In the second resin layer forming step, the ultraviolet curable paint, which is the resin liquid, is discharged from the droplet discharge device so that a part of the base coating film layer is exposed, and a plurality of the resin films are sequentially laminated. A step of forming a design layer made of the second resin layer that has been formed,
In the second resin layer forming step, ultraviolet rays are irradiated each time an upper resin film is formed over one resin film to polymerize the adjacent resin films with ultraviolet rays, or the design layer is formed. 13. The method for manufacturing a painted aluminum container according to any one of claims 9 to 12, wherein after laminating all the resin films constituting the above, the entire resin film is subjected to ultraviolet polymerization.

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