JP7739804B2 - Antibacterial photocurable topcoat paint, laminate and method for manufacturing same, packaging container member and method for manufacturing same, and packaging container - Google Patents

Description

The present invention relates to an antibacterial photocurable topcoat paint. It also relates to a laminate comprising a topcoat film that is a cured product of the antibacterial photocurable topcoat paint, and a method for manufacturing the same. It also relates to a packaging container member comprising the laminate, a method for manufacturing the same, and a packaging container comprising the packaging container member.

Photocurable compositions exhibit photocurability through polymerization and crosslinking when exposed to actinic rays such as ultraviolet light, which means that a heating process is generally not required, resulting in excellent productivity. For this reason, they are particularly useful for adherends that cannot be heated, and are widely used in a variety of applications.

For example, Patent Document 1 discloses a photocurable resin composition suitable for use in optical three-dimensional modeling. Specifically, the proposed photocurable resin composition contains a cationic polymerizable organic compound, a cationic photopolymerization initiator, an ethylenically unsaturated monomer, a radical photopolymerization initiator, and a polyether polyol having three or more hydroxyl groups per molecule, with at least 60% by mass of the ethylenically unsaturated monomer being a polyfunctional monomer having three or more ethylenically unsaturated bonds per molecule. Patent Document 2 also discloses an actinic radiation-curable composition suitable for use as a hard coat film, containing an acrylic compound, an alicyclic epoxy compound, and a curing catalyst. Patent Document 3 also discloses a photocurable composition for antibacterial coatings, composed of a photocurable acrylate-based polymerizable monomer containing a silver salt as an antibacterial agent.

Photocurable compositions are also used as topcoats for metal cans, such as art cans for storing sweets or tea leaves, aerosol cans for insecticides, and pull-top cans. The topcoat functions as a topcoat layer that protects designs, etc., made of an ink layer applied to the surface of the metal can. Such metal cans are available in three-piece and two-piece types.
A three-piece can body is manufactured by sequentially forming a primer layer, an ink layer, and a top coat on a flat metal plate, cutting a rectangular piece for one can from the coated metal plate, rolling the rectangular piece into a cylindrical shape with the top coat facing outward, and joining the overlapping ends. The resulting cylindrical can body has open ends. A bottom member is attached to one open end of the cylindrical can body, and a lid member is attached to the other open end to allow contents to be placed inside and removed, completing the packaging container.

Two-piece can bodies are further classified into a type in which a top coating film or the like is formed before the metal plate is processed, and a type in which a top coating layer or the like is formed after the metal plate is processed.
The former two-piece type can body is manufactured by forming a primer layer, an ink layer, and a top coat in that order on a flat metal plate, cutting a small piece for one can from the coated metal plate, and molding the small piece so that the top coat and other layers are on the outer surface of the container, thereby producing a cup-shaped member with an integrated peripheral wall (also called a side wall) and a bottom (hereinafter sometimes referred to as a "first-coated, second-formed" two-piece type). The shape of the small piece can be selected depending on the shape of the container to be manufactured.
The latter two-piece can body is manufactured by first preparing a small piece for one can from a flat metal plate. The small piece is then molded into a cup shape with a peripheral wall (side surface) and a bottom surface integrated together. The peripheral wall (side surface) is then optionally processed to increase its height, and a primer layer, an ink layer, and a top coat are sequentially formed on the outer surface of the peripheral wall (side surface) (hereinafter, this may be referred to as a "pre-formed, post-coated" two-piece type). The shape of the small piece can be selected depending on the shape of the container to be manufactured.
The two-piece can body thus produced has an opening at one end, and a lid member is attached to the opening to allow the contents to be removed after they have been placed inside, thereby forming a packaging container.

A packaging container can also be made by attaching a bottom member to one open end of a three-piece cylindrical can body and combining a relatively shallow two-piece member as a lid member with the other open end. Figure 7 shows a schematic perspective view of such a packaging container. The body 71 of the packaging container 70 is made up of two parts, and the lid 75 is made up of one part. The body 71 has a cylindrical can body 72 formed by cutting a flat painted metal plate into a cylindrical shape and joining it at a seam 74, and a bottom member 73 attached to one open end of the can body 72. The lid 75 is made from a flat painted metal plate with the top and sides three-dimensionally machined into a single part, and is configured to be able to open and close freely relative to the body 71.

The can body of an art can is mainly a three-piece type. The can body of a pull-top can and the lid of an art can are mainly two-piece types that are "pre-coated and post-formed." The can body of a beverage can and aluminum aerosol can is mainly two-piece types that are "pre-formed and post-coated."

Japanese Patent Application Publication No. 09-278811 JP 2016-102193 A Japanese Patent Application Publication No. 8-311373

Topcoats used on metal cans are required to have excellent adhesion to a wide variety of materials, as a wide variety of surfaces (primer coats, ink layers, etc.) are required. Furthermore, in the case of a three-piece can, when joining the can body to the bottom and lid components, the opening edge of the can body is gradually narrowed, and then the bottom and lid components are deformed by tightening them. In the case of a two-piece can, similar deformation is applied to the opening edge of the lid when joining the peripheral wall and lid components. Alternatively, the can body (peripheral wall) may be deformed to form irregularities to add design and improve strength. The relatively shallow lid components produced with the two-piece can also undergo similar deformation at the opening edge. Therefore, there is a strong demand in the market for topcoats that can maintain adhesion even after these deformation processes. Furthermore, light-curable topcoats with extremely low solvent content have recently attracted attention from the perspective of reducing environmental impact, and there is a need for technology that further reduces the amount of radiation exposure required for curing. Additionally, there is a demand for paints that can form antibacterial coatings for applications such as beverage cans and powdered milk cans.

Note that while the above describes issues with photocurable topcoats used on metal cans, similar issues can arise with photocurable topcoats in general.

The present invention has been made in light of the above background, and aims to provide a photocurable topcoat paint that can form a topcoat film that has excellent adhesion to the surface to be coated (undercoat film, ink layer, etc.) even when cured with low exposure, has excellent adhesion after processing, and also has antibacterial properties; a laminate and a method for manufacturing the same; a packaging container component and a method for manufacturing the same; and a packaging container.

As a result of extensive research, the present inventors have found that the problems of the present invention can be solved by the following aspects, and have thus completed the present invention.
[1]: a cationic polymerizable compound (A) having an epoxy group, a polyol (B) having two or three hydroxyl groups in one molecule and having a number average molecular weight of 2000 or less, and a cationic photopolymerization initiator (C),
The composition contains a trifunctional radical polymerizable monomer (D), a radical photopolymerization initiator (E), a polydimethylsiloxane-based leveling agent (F), and a silver-based compound (G),
the content of the radical polymerizable monomer (D) is 5 to 35% by mass relative to 100% by mass of the total of the cationically polymerizable compound (A), the polyol (B), and the radical polymerizable monomer (D);
the content of the cationic photopolymerization initiator (C) is 3 to 15 parts by mass relative to 100 parts by mass in total of the cationic polymerizable compound (A) and the polyol (B);
the content of the radical photopolymerization initiator (E) is 1 to 10 parts by mass relative to 100 parts by mass of the radical polymerizable monomer (D);
and the antibacterial activity value of the cured coating film according to JIS Z2801 is 2 or more.
Antibacterial photocurable topcoat paint [2]: The antibacterial photocurable topcoat paint according to claim 1, wherein the cured coating film has an antiviral activity value according to JIS L1922 of 2 or more.
[3]: The antibacterial photocurable topcoat paint according to [1] or [2], having a surface tension of 29 mN/m or less.
[4]: A laminate comprising a metal substrate, an undercoat coating film, an ink layer, and a topcoat coating film in this order, wherein the topcoat coating film is a cured product of the antibacterial photocurable topcoat paint described in any one of [1] to [3]. [5]: The laminate according to [4], wherein the surface free energy of the topcoat coating film is 25 mJ/ ^m2 or more.
[6]: A packaging container member, comprising the laminate according to [4] or [5] in the form of a cylindrical body, the outer surface of the cylindrical body being coated with the topcoat coating film, and the cylindrical body having a seam.
[7]: The packaging container member according to [6], wherein the joint on the outer surface of the cylindrical body is coated with a protective coating film.
[8]: The packaging container member according to [6] or [7], further comprising a bottom member that closes the opening at the bottom of the cylindrical body.
[9]: An integrally molded product formed from the laminate according to [4] or [5], the inner surface of which is concave due to the peripheral wall portion and the bottom surface portion,
A packaging container member, wherein the outer surface of the integrally molded product is the topcoat coating film.
[10]: A packaging container comprising a container body having the packaging container member according to [8] or [9], and a lid member attached to the container body to cover the opening of the container body.
[11]: forming a primer coating film on a metal substrate;
forming an ink layer on the undercoat film;
A method for producing a laminate, comprising applying the antibacterial photocurable topcoat paint according to any one of [1] to [3] onto the ink layer and curing it to form a topcoat coating film.
[12]: The method for producing a laminate according to [11], wherein the curing step of the antibacterial photocurable topcoat coating is carried out by irradiating the antibacterial photocurable topcoat coating with light in a wavelength range of 320 nm or more and 390 nm or less so that the cumulative light amount is 200 mJ/ ^cm2 or less.
[13]: forming a primer coating film on a metal substrate;
forming an ink layer on the undercoat film;
[0033] Applying the antibacterial photocurable topcoat paint according to any one of [1] to [3] onto the ink layer and curing it to form a topcoat coating film to obtain a laminate;
Using the laminate, a cylindrical body is formed, the outer surface of which is the topcoat coating film, and the peripheral wall portion includes a seam;
A method for manufacturing a packaging container member, comprising a step of covering the joint on the outer surface of the cylindrical body with a protective coating film.
[14]: forming a primer coating film on a metal substrate;
forming an ink layer on the undercoat film;
[0033] Applying the antibacterial photocurable topcoat paint according to any one of [1] to [3] onto the ink layer and curing it to form a topcoat coating film to obtain a laminate;
A method for manufacturing a packaging container member, comprising a step of using the laminate to form an integrally molded product whose inner surface is concave due to the peripheral wall portion and the bottom surface portion, and whose outer surface is the topcoat coating film.
[15]: The method for manufacturing a packaging container member according to [13] or [ ¹⁴ ], wherein the curing step of the antibacterial photocurable topcoat paint is carried out by irradiating the antibacterial photocurable topcoat paint with light in a wavelength range of 320 nm or more and 390 nm or less so that the cumulative light amount is 200 mJ/cm2 or less.

The present invention has the excellent effect of providing an antibacterial photocurable topcoat paint, a laminate and a method for producing the same, a packaging container member and a method for producing the same, and a packaging container that can form a topcoat film that has excellent adhesion to the surface to be coated (such as an undercoat film or ink layer) and excellent adhesion after processing, even when cured at a ^low exposure dose. For example, the present invention provides an antibacterial photocurable topcoat paint, a laminate and a method for producing the same, a packaging container member and a method for producing the same, and a packaging container that can form a topcoat film that has excellent adhesion to the surface to be coated (such as an undercoat film or ink layer) and excellent adhesion after processing, by irradiating the surface with light in the UVA wavelength range (320-390 nm) with an integrated light dose of 200 mJ/cm2 or less.

FIG. 2 is a schematic top view showing an example of a laminate according to the present embodiment. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 1 (a modified example of FIG. 2). FIG. 2 is a schematic perspective view showing an example of a packaging container member according to the present embodiment. FIG. 5 is a partially enlarged explanatory view of a region V in FIG. 4 . 3A to 3C are schematic explanatory views of essential parts illustrating an example of a method for joining members for packaging containers according to the present embodiment. FIG. 1 is a schematic perspective view showing an example of a metal can in which a container body made of two parts and a lid member made of one part are combined.

The present invention will be described in detail below. It goes without saying that other embodiments are also included within the scope of the present invention as long as they conform to the spirit of the present invention. Furthermore, in this specification, numerical ranges specified using "to" include the numerical values written before and after "to." Furthermore, in this specification, "film" and "sheet" are not distinguished by thickness. Furthermore, unless otherwise noted, the various components appearing in this specification may be used independently, either alone or in combination of two or more types. Furthermore, the same reference numerals are used to refer to the same or equivalent components.

[[Antibacterial light-curing topcoat paint]]
The antibacterial photocurable topcoat paint (hereinafter referred to as "the paint") according to this embodiment contains a cationically polymerizable compound (A) having an epoxy group (hereinafter referred to as "cationically polymerizable compound (A)"), a polyol (B) having two or three hydroxyl groups per molecule and a number average molecular weight of 2000 or less (hereinafter referred to as "polyol (B)"), a cationic photopolymerization initiator (C), a trifunctional radically polymerizable monomer (D) (hereinafter referred to as "radical polymerizable monomer (D)"), a radical photopolymerization initiator (E), a polydimethylsiloxane-based leveling agent (F) (hereinafter referred to as "leveling agent (F)"), and a silver-based compound (G). The content of the radically polymerizable monomer (D) is 5 to 35% by mass relative to 100% by mass of the total of the cationically polymerizable compound (A), polyol (B), and radically polymerizable monomer (D). The content of the cationic photopolymerization initiator (C) is 3 to 15 parts by mass per 100 parts by mass of the total of the cationic polymerizable compound (A) and the polyol (B), and the content of the radical photopolymerization initiator (E) is 1 to 10 parts by mass per 100 parts by mass of the radical polymerizable monomer (D). The antibacterial activity value according to JIS Z2801 of a cured coating film formed from this coating material is 2 or more.

By applying this paint to a surface to be coated and irradiating it with actinic rays, a cured topcoat film is formed on the surface. The topcoat film is a topcoat layer that functions as a finishing varnish. The topcoat film protects the surface to be coated. Furthermore, if the surface to be coated is printed, the topcoat film not only adequately protects the printed surface during processing and transportation, but also improves the adhesion of the printed layer.

This paint can be obtained by uniformly mixing each component. The term "cured product" refers to the paint cured by irradiating it with actinic rays. Examples of actinic rays include ultraviolet light, visible light, infrared light, X-rays, alpha rays, beta rays, and gamma rays. Of these, ultraviolet light and visible light are preferred for ease of handling, with ultraviolet light being more preferred, and within these, the UVA wavelength range is preferred. In this specification, the UVA wavelength range refers to wavelengths of 320-390 nm.

There are no particular limitations on the uses of this paint, and there are no particular limitations on the material of the surface to be coated. This paint can be widely used, for example, as a paint for a topcoat to cover a surface to be coated that has formed on it an intermediate layer such as a primer coat and/or a printed ink layer. It can also be used to apply directly onto a substrate.

This paint is particularly suitable as a topcoat for printed metal cans. Metal cans can be manufactured by processing a laminate in which a topcoat is formed via an intermediate layer (primer coat and ink layer), i.e., the three-piece type method mentioned above, the two-piece type pre-coated and post-formed method, or the pre-formed and post-coated method.

Generally, when a cationic polymerizable component is used as the photopolymerizable component of a coating material, the curing speed required to obtain a coating film is slower than when a radically polymerizable component is used. One way to increase the curing speed is to increase the amount of cationic photopolymerization initiator (C). However, if the amount of initiator is too large, the surface layer will cure quickly, but the deeper the layer, the more light is absorbed by the cationic photopolymerization initiator (C) contained in the coating film in the upper layer, making it difficult for sufficient light to reach the deeper layers, thereby inhibiting uniform curing. Furthermore, when a cationic polymerizable component is used, an integrated light dose of 250 mJ/cm ² (UVA wavelength range) or more is usually required, and in some cases, an integrated light dose of about 1 J/cm ² (UVA wavelength range) is required. On the other hand, radically polymerizable components generally have a fast curing speed, but due to large curing shrinkage, they tend to become hard and brittle, and their adhesion is likely to be reduced compared to cationic polymerizable compounds (A).

This coating composition, which combines a cationically polymerizable component and a radically polymerizable component with a leveling agent (F), provides a photocurable topcoat coating that exhibits excellent curability even when cured at low exposure doses, and can form a topcoat coating that exhibits excellent adhesion to the surface being coated (such as an undercoat or ink layer) and excellent adhesion after processing. By combining a cationically polymerizable compound (A) having an epoxy group and a polyol (B) as the cationic component with a specific amount of a trifunctional radically polymerizable monomer (D) as the radical component, curing at low exposure doses is possible, allowing for appropriate control of the curing speed and cure shrinkage. This coating composition is particularly suitable for applications requiring irradiation with UVA light at an integrated light dose of 200 mJ/cm or ^less .

Furthermore, by combining the leveling agent (F) with the above-mentioned components, it is possible to significantly improve adhesion to the surface to be coated (undercoat film, ink layer, etc.). Furthermore, by combining the above-mentioned specific amounts of the cationic photopolymerization initiator (C) and the radical photopolymerization initiator (E) with the above-mentioned components, it is possible to provide a photocurable topcoat paint that can suppress curing inhibition while also improving adhesion after processing.
Although the present paint is suitable for use in low light exposure, this does not mean that the paint can be exposed to high light exposure. Each component of the present paint will be described in detail below.

[Cationically polymerizable compound (A)]
The cationically polymerizable compound (A) is a compound having at least one epoxy group, and is preferably a polyfunctional epoxy compound having two or more epoxy groups. It refers to a compound that polymerizes or crosslinks by cations. It is preferable to use 60 to 100 mass% of the cationically polymerizable compound (A) having two or more epoxy groups, based on 100 mass% of the cationically polymerizable compound (A). From the viewpoint of effectively suppressing cure shrinkage, it is more preferable to use 60 to 100 mass% of the cationically polymerizable compound (A) having two epoxy groups, based on 100 mass% of the cationically polymerizable compound (A).

Specific examples of the cationically polymerizable compound (A) include a cationically polymerizable compound (a1) having an alicyclic epoxy group (hereinafter also referred to as "compound (a1)" or alicyclic epoxy compound (a1)) and a cationically polymerizable compound (a2) having a glycidyl ether group (hereinafter also referred to as "compound (a2)" or compound (a2) having a glycidyl ether group).

As the cationically polymerizable compound (A), it is preferable to use an alicyclic epoxy compound (a1) from the viewpoint of reducing cure shrinkage and optimizing the cure speed. Furthermore, from the viewpoint of improving processing adhesion, it is preferable to use a compound (a2) having a glycidyl ether group in combination. By using a highly reactive compound (a1) in combination with a compound (a2) whose reactivity is lower than that of (a1), it is possible to easily adjust the balance between cure speed, cure shrinkage, and processing adhesion. Furthermore, while excellent film-forming properties can be obtained by using compound (a1), viscosity can be adjusted with compound (a2) to improve coatability. A more suitable combination of compound (a1) and compound (a2) is a combination of a cationically polymerizable compound having a bifunctional alicyclic epoxy group and a cationically polymerizable compound having a bifunctional glycidyl ether group.

The total content of compound (a1) and compound (a2) is preferably 60 to 100% by mass out of 100% by mass of cationically polymerizable compound (A). Furthermore, a mass ratio of compound (a1) to compound (a2) in the range of 100:0 to 60:40 is preferred from the viewpoints of curing speed and reduced cure shrinkage. Furthermore, a mass ratio of compound (a1) to compound (a2) in the range of 90:10 to 65:35 is even more preferred from the viewpoint of processing adhesion. Note that an alicyclic epoxy group refers to a group that forms an epoxy bond on the ring of a cycloalkane having 4 to 12 carbon atoms. The cationically polymerizable compound (A) can be used alone or in combination of two or more types.

Examples of the alicyclic epoxy compound (a1) include 4-vinylcyclohexene monoepoxide, norbornene monoepoxide, limonene monoepoxide, limonene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis-(3,4-epoxycyclohexylmethyl)adipate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexanone-meta-dioxane, and 3,4-epoxycyclohexylmethyl methacrylate.
Examples of commercially available products include Celloxide 2021P, Celloxide 2081, Celloxide 2000, Cyclomer M100, and Epolead GT-401 (all manufactured by Daicel Corporation).

Examples of the compound (a2) having a glycidyl ether group include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, brominated bisphenol A diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, and 1,4-bis[(oxiran-2-ylmethoxy)methyl]cyclohexane.
Commercially available products include Rikaresin HBE-100, Rikaresin DME-100, Rikaresin L-200, Rikaresin BPO-20E, and Rikaresin BEO-60E (all manufactured by New Japan Chemical Co., Ltd.), Denacol EX-121, Denacol EX-141, Denacol EX-145, Denacol EX-212, Denacol EX-211, and Denacol EX- -201, Denacol EX-252, Denacol EX-850, Denacol EX-851, Denacol EX-612, Denacol EX-313, Denacol EX-314, Denacol EX-421, Denacol EX-321, Denacol EX-321L, Denacol EX-411 (all manufactured by Nagase ChemteX Corporation) and the like.

From the perspective of ensuring and improving adhesion and processability, the content of the cationic polymerizable compound (A) is preferably 50 to 85% by mass relative to 100% by mass of the cationic polymerizable compound (A), polyol (B), cationic photopolymerization initiator (C), trifunctional radical polymerizable monomer (D), and radical photopolymerization initiator (E). A more preferred range is 55 to 75% by mass.

[Polyol (B)]
The polyol (B) is a compound having two or three hydroxyl groups per molecule and a number average molecular weight (hereinafter, abbreviated as Mn) of 2,000 or less. It can be appropriately selected from conventionally known polyols. By using a polyol (B) having two or three hydroxyl groups per molecule, processing adhesion can be improved.

As the polyol (B), various polyether polyols, polyester polyols, polycarbonate polyols, polybutadiene glycols, etc. can be used.
Examples of polyether polyols include polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, and the like.

Polyester polyols include saturated or unsaturated low-molecular-weight diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butylene diol, diethylene glycol, triethylene glycol, dipropylene glycol, or dimer diol, and adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric ... Examples include polyester polyols obtained by reacting dicarboxylic acids such as taric acid, pimelic acid, suberic acid, azelaic acid, or sebacic acid, or their anhydrides; alkyl glycidyl ethers such as n-butyl glycidyl ether or 2-ethylhexyl glycidyl ether; polyester polyols obtained by reacting monocarboxylic acid glycidyl esters such as versatic acid glycidyl ester with anhydrides of the above dicarboxylic acids in the presence of hydroxyl group-containing compounds such as alcohols; and polyester polyols obtained by ring-opening polymerization of cyclic ester compounds.

Examples of polycarbonate polyols include:
1) a reaction product of a glycol or bisphenol with a carbonate ester, or 2) a reaction product obtained by reacting a glycol or bisphenol with phosgene in the presence of an alkali, or the like can be used.
Examples of glycols used in the above 1) or 2) include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, butylene glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, octanediol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, 3,9-bis(1,1-dimethyl-2-hydroxyethyl), 2,2,8,10-tetraoxospiro[5.5]undecane.

Of these, polyether polyols are preferred as polyol (B) from the standpoint of ease of handling.

Examples of polyether polyols include the reaction product of addition polymerization of one or more oxirane compounds using a compound with two or three hydroxyl groups per molecule as an initiator. Examples of compounds with two or three hydroxyl groups per molecule include ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, and trimethylolpropane. Examples of oxirane compounds include alkylene oxides such as ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO), and cyclic ether compounds such as tetrahydrofuran (THF).

The polyether polyol is preferably a polyoxyalkylene polyol having an alkyleneoxy group. Suitable examples include EO-modified trimethylolpropane, PO-modified trimethylolpropane, tetrahydrofuran-modified trimethylolpropane, EO-modified glycerin, PO-modified glycerin, tetrahydrofuran-modified glycerin, polyethylene glycol, polypropylene glycol, polyoxypropylene glyceryl ether, etc. Among these, EO-modified trimethylolpropane, PO-modified trimethylolpropane, EO-modified glycerin, PO-modified glycerin, polyethylene glycol, polypropylene glycol, and polyoxypropylene glyceryl ether are preferred.
The terms EO-modified and PO-modified refer to (poly)alkylene oxide modifications such as ethylene oxide modification and propylene oxide modification, and refer to the addition of (poly)alkylene oxide units.

Commercially available polyether polyols include Sannix TP-400 (Mn: 400), Sannix GP-250 (Mn: 250), Sannix GP-400 (Mn: 400), Sannix GP-600 (Mn: 600), Sannix GP-1000 (Mn: 1000), Sannix PP-200 (Mn: 200), Sannix PP-400 (Mn: 450), Sannix PP-600 (Mn: 600), Sannix PP-1000 (Mn: 1000), Examples include PEG-200 (Mn: 200), PEG-400 (Mn: 400), PEG-600 (Mn: 600), PEG-1000 (Mn: 1000) (all manufactured by Sanyo Chemical Industries, Ltd.), Exenol 430 (Mn: 430), Exenol 1030 (Mn: 1000), Exenol 420 (Mn: 400), Exenol 720 (Mn: 700), Exenol 1020 (Mn: 1000), and Exenol 2020 (Mn: 2000) (all manufactured by AGC).

The number average molecular weight (Mn) of polyol (B) is 2000 or less. By setting the Mn of polyol (B) to 2000 or less, dispersibility in the coating material can be improved, resulting in superior processing adhesion. It is more preferably 1700 or less, and even more preferably 1500 or less. There are no particular restrictions on the lower limit of the molecular weight of polyol (B), but from the viewpoint of improving curability, it is preferably 100 or more, more preferably 200 or more, and even more preferably 300 or more.

From the viewpoint of achieving better processing adhesion and antibacterial properties, the content of polyol (B) is preferably 2 parts by mass or more per 100 parts by mass of cationically polymerizable compound (A). It is more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more. Furthermore, from the viewpoint of improving curability, it is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less.

Polyol (B) can be used alone or in combination of two or more types. Polyol (B) is a compound having two or three hydroxyl groups per molecule, but this does not preclude the inclusion of polyols having one or four or more hydroxyl groups per molecule in this paint, provided that this does not deviate from the spirit of the present invention.

[Cationic Photopolymerization Initiator (C)]
The cationic photopolymerization initiator (C) refers to a compound that, when irradiated with actinic rays, releases a cation that initiates the polymerization or crosslinking reaction of the cationically polymerizable compound (A).

Various compounds are known as cationic photopolymerization initiators (C), including diazonium compounds, sulfonium compounds, iodonium compounds, and metal complex compounds. Detailed descriptions can be found in, for example, "Functional Materials," October 1985, item 5, and "Applications and Markets of UV/EB Curing Technology," CMC Publishing, 1989, page 78. Specific examples include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, triphenyliodonium hexafluoroantimonate, diphenyl(4-(phenylthio)phenyl)sulfonium hexafluoroantimonate, bis(4-(diphenylsulfonio)phenyl)sulfide bis(hexafluoroantimonate), diphenyl(4-(phenylthio)phenyl)sulfonium hexafluorophosphate, and bis(4-(diphenylsulfonio)phenyl)sulfide bis(hexafluorophosphate). The cationic photopolymerization initiator (C) can be used alone or in combination of two or more types.

Commercially available products containing cationic photopolymerization initiator (C) include, for example, CPI-100P (50% active ingredient), CPI-101A (50% active ingredient), CPI-200K (50% active ingredient), CPI-110B (100% active ingredient), CPI-310FG (100% active ingredient), CPI-310B (100% active ingredient), CPI-410S (100% active ingredient), and CPI-410B (100% active ingredient). ), IK-1 (active ingredient 100%) (all manufactured by San-Apro Co., Ltd.), Omnicat 250 (active ingredient 75%), Omnicat 270 (active ingredient 100%), Omnicat 432 (active ingredient 45%) (all manufactured by IGM Co., Ltd.), WPI-113 (active ingredient 50%) (manufactured by Wako Pure Chemical Industries, Ltd.), AT-6992 (active ingredient 60%), AT-6976 (active ingredient 60%) (all manufactured by Aceto Pharmaceuticals).

The content of cationic photopolymerization initiator (C) is 3 to 15 parts by mass per 100 parts by mass of the total of cationically polymerizable compound (A) and polyol (B). By using this range in this paint, a topcoat coating film with excellent curing properties can be obtained, even at low exposure levels. It also optimizes cure shrinkage and cure speed, resulting in a coating film with excellent adhesion to the coated surface. Furthermore, it results in a topcoat coating film with excellent adhesion after processing. The preferred content of the cationic photopolymerization initiator (C) is 4 to 13 parts by mass, with a more preferred range being 5 to 12 parts by mass.

[Trifunctional radically polymerizable monomer (D)]
The radical polymerizable monomer (D) is a monomer having three functional groups per molecule that are radically polymerizable and/or crosslinkable. The presence or absence of other functional groups and the number of functional groups are not limited. The content of the radical polymerizable monomer (D) is 5 to 35% by mass relative to 100% by mass of the total of the cationically polymerizable compound (A), polyol (B), and radical polymerizable monomer (D). By using a content of 5% by mass or more, excellent adhesion to various coated surfaces can be achieved. Furthermore, excellent adhesion after processing can be achieved. Furthermore, by using a content of 35% by mass or less, distortion during curing can be reduced. A more preferred range is 6 to 32% by mass, and an even more preferred range is 7 to 30% by mass.

Suitable examples of the polymerizable group and/or crosslinkable group of the radically polymerizable monomer (D) include a (meth)acryloyl group and a vinyl group. The use of a bifunctional radically polymerizable monomer tends to result in reduced curability, while the use of a tetrafunctional or higher functional radically polymerizable monomer tends to result in reduced adhesion during processing. The use of a trifunctional radically polymerizable monomer (D) results in a coating film that combines curability, adhesion, and post-processing adhesion. The radically polymerizable monomer (D) may be used alone or in combination of two or more types. Note that the use of a bifunctional radically polymerizable monomer and a tetrafunctional or higher functional radically polymerizable monomer is not excluded, provided that it does not deviate from the spirit of the present invention.

Examples of the radically polymerizable monomer (D) having a (meth)acryloyl group include trimethylolpropane tri(meth)acrylate, trimethylolpropane ethyleneoxy-modified tri(meth)acrylate, propyleneoxy-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and isocyanuric acid ethyleneoxy-modified tri(meth)acrylate.

Examples of the radically polymerizable monomer (D) having a vinyl group include trimethylolpropane trivinyl ether and ethyleneoxy-added trimethylolpropane trivinyl ether (TMPEOTVE).

[Radical Photopolymerization Initiator (E)]
The radical photopolymerization initiator (E) is a compound that releases radicals that initiate the polymerization or crosslinking reaction of the radical polymerizable monomer (D) upon irradiation with actinic rays. The content of the radical photopolymerization initiator (E) is 1 to 10 parts by mass per 100 parts by mass of the radical polymerizable monomer (D). By using the radical photopolymerization initiator (E) in this range, poor curing can be prevented and an excellent cured film can be obtained. The radical photopolymerization initiator (E) is not particularly limited, and known compounds can be used. Specific examples include benzophenone compounds, dialkoxyacetophenone compounds, α-hydroxyalkylphenone compounds, α-aminoalkylphenone compounds, and acylphosphine oxide compounds.

Examples of benzophenone compounds include benzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, [4-(methylphenylthio)phenyl]phenylmethanone, benzophenone-2-methyl carboxylate, and compounds with two or more benzophenone structures.

Examples of dialkoxyacetophenone compounds include 2,2-dimethoxy-2-phenylacetophenone, dimethoxyacetophenone, and diethoxyacetophenone.

Examples of α-hydroxyalkylphenone compounds include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and 2-hydroxy-1-[4-(2-hydroxyethoxy)-phenyl]-2-methyl-1-propan-1-one.

Examples of α-aminoalkylphenone compounds include 2-methyl-1-[4-(methoxythio)-phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl-1-butanone, and compounds having two or more α-aminoalkylphenone structures.

Examples of acylphosphine oxide compounds include diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

From the viewpoint of the transparency of the cured coating film, it is preferable to use a compound selected from the group consisting of α-hydroxyalkylphenone compounds and acylphosphine oxide compounds.

Commercially available products include Omnirad 184, 907, 651, 1173, 819, 369E, and TPO H (all manufactured by IGM). The radical photopolymerization initiator (E) can be used alone or in combination of two or more types.

[Polydimethylsiloxane-based leveling agent (F)]
The polydimethylsiloxane leveling agent (F) (hereinafter also referred to as leveling agent (F)) improves the wettability of the underlying layer of the paint with the surface to be coated, and functions to make the topcoat film obtained from the paint smoother. By using the leveling agent (F), it is possible to more suitably adjust the adhesion to the surface to be coated (undercoat film, intermediate layer such as ink layer).

Examples of leveling agents (F) include polyether-modified polydimethylsiloxanes (those without hydroxyl groups or acryloyl groups, those with hydroxyl groups, and those with acryloyl groups), polyester-modified polydimethylsiloxanes (those without hydroxyl groups or acryloyl groups, those with hydroxyl groups, and those with acryloyl groups), and polyetherester-modified polydimethylsiloxanes (those without hydroxyl groups or acryloyl groups, those with hydroxyl groups, and those with acryloyl groups). Leveling agents (F) may be used alone or in combination.

Commercially available leveling agents (F) include BYK 333, 377, 378, UV 3500, and UV 3510 (all manufactured by BYK Corporation), and TEGO Glide 410, 435, and 450 (all manufactured by Evonic Corporation).

The content of leveling agent (F) can be selected appropriately depending on the type of surface to be coated or the type of protective coating to be formed on top. From the perspective of maintaining good wettability and penetration into the surface to be coated, the content of leveling agent (F) is preferably 0.005 parts by mass or more per 100 parts by mass of the total of cationically polymerizable compound (A), polyol (B), cationic photopolymerization initiator (C), radically polymerizable monomer (D), and radical photopolymerization initiator (E). It is more preferably 0.01 parts by mass or more, and even more preferably 0.02 parts by mass or more.

As described below, a protective coating may be partially formed on the topcoat. Information such as expiration dates may also be printed on the topcoat using inkjet printing or other methods. For this reason, the topcoat is also required to have excellent adhesion to these protective coatings and other overlying layers. To ensure excellent adhesion to the surface to be coated and to layers formed on the topcoat, the content of the leveling agent (F) is preferably 2 parts by mass or less per 100 parts by mass of the total of the cationic polymerizable compound (A), polyol (B), cationic photopolymerization initiator (C), radically polymerizable monomer (D), and radical photopolymerization initiator (E). This range of the leveling agent content also enhances the dispersibility of the leveling agent (F) within the cured film when the paint is applied to form a cured film. A content of 1 part by mass or less is more preferred, and 0.8 parts by mass or less is even more preferred.

<Silver compound (G)>
The silver-based compound (G) in the present invention is a compound containing silver. The silver-based compound (G) functions as an antibacterial agent and can also function as an active ingredient of an antiviral agent, an antifungal agent, or a deodorizer.
Therefore, a topcoat film using the silver-based compound (G) can exhibit antiviral effects in addition to antibacterial effects.

The mechanism by which the topcoat coating of the present invention exhibits antibacterial properties is thought to be as follows: When the silver-based compound (G) comes into contact with moisture, the slight moisture permeability of the polyol (B) allows moisture to penetrate into the silver-based compound. This moisture elutes silver ions. The amount of eluted silver ions remains approximately constant over a certain period of time. These positively charged silver ions are attracted to the negatively charged surface of bacteria. This disrupts the electrical balance on the surface of the bacteria, rupturing the cell membrane and killing the bacteria. The silver ions then penetrate into the cells and bind to intracellular enzymes, thereby inactivating the enzymes. They also react with the DNA of bacteria, causing it to lose its function and reducing its reproductive ability. It is believed that the antibacterial effect of the silver ions completely prevents the proliferation of bacteria on the surface of the coating layer.

Examples of the silver-based compound (G) include silver compounds such as simple silver, silver oxide, inorganic silver salts such as silver carbonate, silver chloride, silver nitrate, silver sulfate, and silver sulfonate, and organic silver salts such as silver formate and silver acetate. The silver salts may also be supported on zeolite, silica gel, low-molecular-weight glass, calcium phosphate, silicate, molybdenum oxide, titanium oxide, etc. (Supported compounds are also referred to as supported compounds or supports).
Examples of the support include zeolite-based silver-supported compounds, silica gel-based silver-supported compounds, silicate-based silver-supported compounds, molybdenum oxide-based silver-supported compounds, and titanium oxide-based silver-supported compounds, which support silver compounds such as simple silver, silver oxide, inorganic silver salts, and organic silver salts.

From the viewpoint of dispersion stability, the silver-based compound (G) is preferably a support in which elemental silver, silver oxide, or an inorganic silver salt such as silver nitrate is supported on a carrier, and more preferably a zeolite-based silver-supported compound or a molybdenum oxide-based silver-supported compound in which a silver compound is supported on zeolite or molybdenum oxide.
Zeolite-based silver-supported compounds and molybdenum oxide-based silver-supported compounds are preferred because they have excellent antibacterial and antiviral properties.

The average primary particle diameter of the silver-based compound (G) used in the present invention is preferably 5 to 100 nm. The average primary particle diameter can be measured by directly observing the particles themselves using, for example, a transmission electron microscope (TEM) or a scanning electron microscope (SEM). An average primary particle diameter of 5 nm or more results in better dispersibility, while an average primary particle diameter of 100 nm or less can form a cured film with superior transparency.

The content of the silver-based compound (G) relative to a total of 100 parts by mass of the cationically polymerizable compound (A), polyol (B), and radically polymerizable monomer (D) of the present invention is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1.0 to 7 parts by mass. A content of 0.1 parts by mass or more makes it possible to obtain a better antibacterial coating film, while a content of 20 parts by mass or less makes it easier to form a coating film with excellent dispersion stability.

The silver-based compound (G) is preferably used as a dispersion to prepare the paint. A preferred method involves dispersing the silver-based compound (G) in a premixed solution containing the cationic polymerizable compound (A), polyol (B), trifunctional radically polymerizable monomer (D), and a diluent (described below) and then blending the remaining components to prepare the paint. A dispersant is preferably blended to stabilize the dispersion state of the silver-based compound (G). The dispersed particle size _D50 of the silver-based compound (G) in the paint is preferably 300 nm or less, more preferably 200 nm or less. The dispersed particle size _D50 can be measured using a "Nanotrack UPA" manufactured by Nikkiso Co., Ltd., using dynamic light scattering. A dispersed particle size _D50 of 300 nm or less can provide superior dispersion stability.

Dispersion can be performed using a dispersing machine such as a paint conditioner (manufactured by Red Devil), ball mill, sand mill (such as Shinmaru Enterprises' "Dyno Mill"), attritor, pearl mill (such as Eirich's "DCP Mill"), Coball mill, homomixer, homogenizer (such as M-Technique's "Clearmix"), wet jet mill (such as Genus's "Genus PY" or Nanomizer's "Nanomizer"), or microbead mill (such as Kotobuki Industries' "Super Apec Mill" or "Ultra Apec Mill"). When using media in a dispersing machine, it is preferable to use glass beads, zirconia beads, alumina beads, magnetic beads, styrene beads, etc. For dispersion, it is acceptable to use two or more types of dispersing machines or two or more types of media of different sizes in a stepwise manner.

<Optional ingredients>
The paint may contain an optional diluent. While the diluent is not limited, suitable examples include methyl propylene glycol and propylene carbonate. Depending on the application, the paint may also contain components that impart a gloss or matte finish.
The coating material may also contain a photosensitizer (polymerization accelerator) as an optional component. Examples of photosensitizers include amine compounds such as triethanolamine, methyldiethanolamine, triethylamine, and diethylamine; thioxanthone, thioxanthone derivatives, anthraquinone, anthraquinone derivatives, anthracene, anthracene derivatives, perylene, perylene derivatives, benzophenone, and benzoin isopropyl ether.

Furthermore, cationically polymerizable compounds and/or radically polymerizable monomers other than those mentioned above may be added to the coating material without departing from the spirit of the present invention. Furthermore, leveling agents other than leveling agent (F) may be added without departing from the spirit of the present invention. Furthermore, wettability improvers, surfactants, plasticizers, ultraviolet absorbers, silane coupling agents, inorganic fillers, resin particles, pigments, dyes, etc. may also be added.

<Surface tension of this paint and surface free energy of topcoat>
From the viewpoint of more effectively improving adhesion to various surfaces to be coated (undercoat coatings, ink layers, etc.), the surface tension of the present coating material is preferably 29 mN/m or less. More preferably, it is 28.5 mN/m or less, and even more preferably, it is 27.5 mN/m or less. The surface tension can be adjusted by adjusting the type and amount of the leveling agent (F) or the type and amount of the diluent. The lower limit of the surface tension is not particularly limited, but is usually 20 mN/m or more.

Furthermore, the surface free energy of the topcoat coating film obtained by applying the present coating material and curing it by light irradiation is preferably 25 mJ/ ^m2 or more, from the viewpoint of improving adhesion to the upper layer film described above. It is more preferably 26.5 mJ/ ^m2 or more, and even more preferably 28 mJ/ ^m2 or more. The surface free energy of the topcoat coating film can be adjusted by adjusting the type and amount of leveling agent (F) added, or by adjusting the type and amount of wax added, for example. The upper limit of the surface free energy is not particularly limited, but is usually 60 mJ/ ^m2 or less.

When the surface tension of this paint is set to 29 mN/m or less and the surface free energy of the topcoat film is set to 25 mJ/ ^m2 or more, it becomes possible to more effectively improve adhesion to the primer film and ink layer while significantly increasing the options for materials to be formed on the topcoat film.

[[Laminate and method for producing the same]]
The laminate according to this embodiment (hereinafter also referred to as "the laminate") has at least a substrate and a topcoat film formed on the substrate. This topcoat film is a cured product of the present paint. Examples of the substrate include metal, plastic, glass, ceramics, and wood. Optional layers, such as an undercoat film and an intermediate layer such as an ink layer, can be formed between the substrate and the topcoat film.

Figure 1 shows a schematic top view of an example of this laminate, and Figure 2 shows a cross-sectional view of the II-II section of Figure 1. As shown in Figure 2, the laminate 10 comprises a metal substrate 20, an undercoat film 30, an ink layer 40, and a topcoat film 50, in that order. The topcoat film 50 serves as the topcoat layer, as shown in Figure 1. The production of the laminate 10 includes steps such as forming the undercoat film 30 on the metal substrate 20, forming the ink layer 40 on this undercoat film 30, applying the present paint onto the undercoat film 30 and the ink layer 40, and curing it by exposure to actinic light to form the topcoat film 50.

The cumulative light intensity for the curing treatment of the topcoat coating film 50 can be designed as appropriate. For example, with this paint, irradiation with light in the wavelength range of 320 nm or more and 390 nm or less at 200 mJ/cm² or ^less provides excellent curability and a topcoat coating film with excellent properties. The lower limit of the cumulative light intensity is not particularly limited as long as it can cure. For example, it is about 50 mJ/ ^cm² .

The laminate 10 may further comprise other layers. At both lateral ends of the laminate 10 (the X direction in FIG. 1), there are uncoated areas 21, which are intended to be joined and in which the metal substrate 20 is exposed in a linear pattern along the Y direction. This laminate 10 is joined by overlapping the uncoated areas 21 at both ends to form a packaging container member 60, which is a cylindrical welded can as shown in FIG. 4, described below. By providing the uncoated areas 21, where the metal substrate 20 is exposed and not covered with a primer coating 30 or the like, poor welding can be prevented when the welded can is formed.

The material of the metal substrate 20 is not particularly limited, and examples include tin plate, chrome-plated steel plate, aluminum plate, aluminum alloy plate, surface-treated steel plate such as tin-free steel, aluminum-plated steel plate, nickel-plated steel plate, tin-nickel-plated steel plate, and various alloy-plated steel plates. It may also be a resin-coated metal plate on which a film made of a thermoplastic resin such as polyester is formed. When a resin-coated metal plate is used as the metal substrate, the coating resin layer may contain a white pigment.

The primer coating film 30 may be composed of one layer as shown in Figure 2, or may be composed of two layers as shown in Figure 3, or three or more layers. When there are two layers of primer coating film 30 as shown in Figure 3, the coating film of the primer coating film 30 that is in direct contact with the metal substrate 20 for the most part will be referred to as the first primer coating film 31, and the coating film further provided on the first primer coating film 31 will be referred to as the second primer coating film 32 for the most part.

The first undercoat film 31 can be formed by a known method. For example, the first undercoat film 31 can be formed by applying an undercoat paint for the first undercoat film onto the metal substrate 20, drying it, and curing it.
The second undercoat film 32 can be formed by applying, drying, and curing a paint for the second undercoat film on the first undercoat film 31. The paint for the second undercoat film 32 may be applied directly to a portion of the metal substrate 20, dried, and cured.
The paint for the first and second primer coating films (hereinafter sometimes referred to as primer paint) can be a composition in which a binder component is dissolved or dispersed in a solvent. A thermosetting compound or a photocurable compound is suitable as the binder component. When a binder component containing a thermosetting compound is used, the primer paint is applied, dried, and then cured by heat. When a binder component containing a photocurable compound is used, the primer paint is cured by irradiation with actinic rays. A thermosetting compound and a photocurable compound may be used in combination. The primer paint can contain a colorless inorganic filler or a colored pigment. For example, an example of a colorless inorganic filler is silica, and an example of a white pigment is titanium dioxide.

There are no particular limitations on the thickness of the first undercoat coating film 31 and the second undercoat coating film 32. The mass per unit area of each coating film can be, for example, 1 to 300 mg/ ^dm2 . When the main purpose is to conceal the background color of the metal substrate 20, the mass can be, for example, 40 to 300 mg/ ^dm2 .

In the example of the laminate 10 shown in Figure 3, the ink layer 40 consists of two layers: a first ink layer 41 and a second ink layer 42. The ink layer may be formed from a single layer, or may be formed from multiple layers (more than two layers). The ink layer 40 can be used to form a pattern on the metal substrate or to form a colored layer. The ink layer 40 may be formed over the entire surface of the primer coating, or may be formed in a desired position as shown in Figure 3.

The ink layer 40 can be obtained by plate printing, such as offset printing or screen printing, in which multiple plates are created to perform multi-color printing, or inkjet printing, which uses ink droplets sprayed from an ink head. Plate printing and inkjet printing can also be used in combination. In plate printing, if the ink layer is composed of multiple layers, each layer is cured separately. Alternatively, each layer can be pre-cured, and the final curing process can be performed after the multiple layers are stacked.

The ink layer 40 can be obtained, for example, by applying an ink containing a binder component (such as a binder component containing a thermosetting compound, a binder component containing an oxidatively polymerizable compound, or a binder component containing a photocurable compound) and a pigment onto the undercoat film 30 and curing it to form a cured film. Known compounds can be used as the binder component for the ink. Examples include alkyd resin, polyester resin, and epoxy resin. The pigment can be either organic or inorganic. A curing agent can also be added as necessary. Optional components such as pigment dispersants, waxes, and stabilizers can also be added.

The thickness of each of the first ink layer 41 and the second ink layer 42 is not limited, but can be, for example, approximately 0.1 to 6 μm. In the example shown in Figure 3, the first ink layer 41 is formed by applying, drying, and curing the first ink on the second undercoat film 32, and then the second ink is applied in the desired position, dried, and cured to form the second ink layer 42, thereby obtaining the ink layer 40.

The topcoat film 50 is formed on the undercoat film 30 and the ink layer 40 so as to cover them. The photocurable topcoat paint of the present paint is applied onto the undercoat film 30 and the ink layer 40 of the laminate 10, and is cured by irradiation with actinic rays to form the topcoat film 50.
For coating, a known coating device can be used, such as a Mayer bar, applicator, brush, spray, roller, gravure coater, die coater, microgravure coater, lip coater, comma coater, curtain coater, knife coater, reverse coater, or spin coater.
The light source of the actinic ray can be appropriately selected. In the case of irradiating with ultraviolet light, examples of the light source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, an LED lamp, a xenon lamp, and a metal halide lamp.

The thickness of the topcoat film can be selected appropriately depending on the application, but 2 to 20 μm is preferred, and 3 to 15 μm is more preferred.

<Modification>
Other examples of the laminate include a laminate having a metal substrate, an undercoat coating film, and a topcoat coating film laminated in this order, and a laminate having a topcoat coating film formed directly on a metal substrate.In addition, paper, plastic film, wood material, glass, stone, etc. can also be used as the substrate instead of a metal substrate.

[[Packaging container member and method of manufacturing the same]]
A packaging container member according to this embodiment includes a member formed using the present laminate. Fig. 4 is a schematic perspective view showing an example of the packaging container member, and Fig. 5 is a partially enlarged explanatory view of the cross section of region V in Fig. 4 . The packaging container member 60 is a cylindrical body formed from the present laminate, and the outer surface of the cylindrical body is coated with a topcoat coating film 50 formed from the present paint. The cylindrical body has a seam 61. The seam 61 of the packaging container member 60 is formed by overlapping and joining the uncoated regions 21, which are to be welded at both ends of the laminate 10 in the X direction, shown in Fig. 1 . A protective coating film 62 is formed on the seam 61 on the outer surface 22 of the cylindrical body (see Fig. 5 ).

As shown in FIG. 5 , the protective coating 62 covers the area centered around the seam 61 on the outer surface 22 of the metal substrate 20, extending to the upper surface of the edge of the adjacent topcoat coating 50. This protects and reinforces the seam 61 and enhances the aesthetic appeal of the packaging container component. An inner protective layer (not shown) may be formed on the inner surface 23 of the metal substrate 20. The protective coating 62 can be formed by known methods. For example, it can be obtained by applying and drying a protective paint. Alternatively, after drying, it may be cured by heat or light to form a cured film. Alternatively, protective tape may be applied instead of the protective coating.

In addition to the above methods, various known methods such as welding, adhesives, soldering, and crimping can be used to join the laminate 10 into a cylindrical body. Figure 6 shows a schematic top view of the crimped portion of packaging container members joined by crimping. As shown in the figure, both ends of the laminate 10 are overlapped, folded, and wrapped to join the cylindrical body. Within the laminate 10, the outer side of the packaging container member 60 is the topcoat coating film 50, and the inner side is the metal substrate 20. Note that when joining by crimping, a laminate in which the undercoat coating film 30, ink layer 40, and topcoat coating film 50 are applied to the entire surface of the metal substrate 20 may be used, without providing the uncoated region 21 (see Figure 1). Furthermore, when using crimping, a protective coating to cover the seam is not necessary.

The cylindrical packaging container member 60 functions as the can body. When manufacturing three-piece cans, a packaging container member (not shown) can be used in which a bottom member that closes the lower opening of the cylindrical body that will become the can body is joined by welding or the like. This member can be suitably used as a packaging container member for canned goods or spray cans.

<Modification>
Another example of a packaging container member of this embodiment is a packaging container member formed from an integrally molded product formed from the sheet-like present laminate and having a recessed peripheral wall and bottom surface. A top coat film formed from the present paint is formed on the outer surface of this integrally molded product. This can be suitably used as a packaging container member for two-piece cans containing food or the like. Since this laminate uses a top coat film that has excellent adhesion after processing, it can also be suitably used as a packaging container member having such an integrally molded product.
In the above embodiment, an example was given in which a metal can was formed using a laminate, but after the metal can was formed, the present coating material can also be used for applications in which a topcoat coating film or the like is formed by applying the coating material to the formed metal can using a spray, a roll, or the like.

[[Packaging container]]
The packaging container of this embodiment includes a container body having the packaging container member of the present invention and a lid member attached to the container body to cover the opening of the container body. The container body can be, as described above, a packaging container member formed by welding or the like to a bottom member that closes the lower opening of a cylindrical body that serves as the can body, or a packaging container member described in a modified example in which the cylindrical peripheral wall and bottom are integrally molded. The opening of the container body refers to an access port for removing the contents contained in the container body. The lid member can be attached to the container body, as in a pull-tab can, or it can be a recessed, openable lid made of a single part, as described in Figure 7.

The present invention will be explained in more detail below, but the following examples are not intended to limit the scope of the present invention. In the examples, "parts" and "%" represent "parts by mass" and "% by mass," respectively, unless otherwise specified.

The average primary particle size of silver-based compound (G) and the dispersed particle size of silver-based compound (G) were measured using the following method.

[Average primary particle diameter of silver-based compound (G)]
The average primary particle diameter was determined by observing with a transmission electron microscope (TEM) using a JEM-2010 transmission electron microscope manufactured by JEOL Ltd., measuring the minor axis diameter and major axis diameter of 10 primary particles, and averaging the measured values to determine the average primary particle diameter.

[Dispersed particle size of silver-based compound (G)]
The dispersed particle size _D50 was measured using a dynamic light scattering method using "Nanotrac UPA" manufactured by Nikkiso Co., Ltd.
<Production of Silver-Based Compound Dispersion>
(Silver-based compound dispersion 1)
A dispersion of silver ions-loaded zeolite was prepared in the following manner.
200 parts of silver ion-supported zeolite (Novalon AGT330, manufactured by Toagosei Co., Ltd.), 10 parts of DisperBYK-111 (manufactured by BYK Japan K.K.) as a dispersant, and 800 parts of Celloxide 2021P (manufactured by Daicel Corporation) were mixed and dispersed under the following conditions to prepare Dispersion 1 containing a silver-based compound (GI) having an average primary particle size of 30 nm and a dispersed particle size D ₅₀ of 80 nm.
Pre-dispersion: Zirconia beads (1.25 mm) were used as media and the mixture was dispersed in a paint shaker for 1 hour.
Main dispersion: Dispersed for 1 hour using zirconia beads (0.1 mm) as media in a disperser UAM-015 manufactured by Kotobuki Industries Co., Ltd.

(Silver-based compound dispersion 2)
A dispersion of silver ions-loaded molybdenum oxide was prepared in the following manner.
195 parts of sodium molybdate dihydrate (Kanto Chemical Co., Inc.) was dissolved in 3,000 parts of ion-exchanged water, and a solution prepared by dissolving 273 parts of silver nitrate (Kanto Chemical Co., Inc.) in 3,000 parts of ion-exchanged water was added dropwise to the solution over 30 minutes with stirring to obtain a precipitate. This precipitate was filtered, washed with ion-exchanged water, and thoroughly dried at 100°C (200 parts). Dispersion 2 containing a silver-based compound (GII) having an average primary particle size of 25 nm and a dispersion particle size _D50 of 70 nm was prepared in the same manner as Silver-based Compound Dispersion 1, except that 200 parts of the precipitate was used instead of Novalon AGT330 in Silver-based Compound Dispersion 1.

(Silver-based compound dispersion 3)
A dispersion of silver ions-loaded zeolite was prepared in the following manner.
Dispersion 3 containing a silver-based compound (GIII) having an average primary particle size of 30 nm and a dispersed particle size _D50 of 90 nm was prepared in the same manner as Silver-based Compound Dispersion 1, except that Zeomic AJ10N (manufactured by Sinanen Zeomic Corporation) was used as the silver ion-supported zeolite instead of Novalon AGT330.

(Silver-based compound dispersion 4)
A dispersion of silver ion-loaded silicate was prepared in the following manner.
Dispersion 4 containing a silver-based compound (GIV) having an average primary particle size of 40 nm and a dispersed particle size D ₅₀ of 110 nm was prepared in the same manner as Silver-based Compound Dispersion 1, except that AIS-NAZ320 (manufactured by JGC Catalysts and Chemicals Co., Ltd.) was used as the silver ion-supported silicate instead of Novalon AGT330.

[Example 1]
The components shown in Table 1 were blended to obtain a photocurable topcoat paint N1 according to Example 1. In Table 1, the blending amount of each component is in parts by mass.
Specifically, 49.67 parts of "Celloxide 2021P (manufactured by Daicel Corporation)," a bifunctional alicyclic epoxy compound, was added as the cationically polymerizable compound (A) to 13.89 parts of the silver-based compound dispersion 2 (containing 2.75 parts of the silver-based compound (GII)), making the total amount of (A) added 60.67 parts. Next, 20 parts of "RD-111 (manufactured by Aditya)," a bifunctional glycidyl ether, and 5.5 parts of "Excenol 420 (manufactured by AGC)," a polyether polyol having two hydroxyl groups and a number average molecular weight of approximately 400, were blended as the polyol (B), and the mixture was stirred with a disper. To this, 60% by weight of non-volatile "AT-6992 (manufactured by Aceto)": 8 parts (including 4.8 parts of cationic photopolymerization initiator (C)), as a radical polymerizable monomer (D), a trifunctional radical polymerizable monomer "Miramer M3130 (manufactured by Miwon)": 5.5 parts, as a radical photopolymerization initiator (E) 100% by weight of non-volatile "Omnirad 1173 (manufactured by IGM)" 0.3 parts, and as a leveling agent (F) 100% by weight of non-volatile "BYK377 (manufactured by BYK)": 0.03 parts were blended in this order, and again stirred with a disperser to prepare the photocurable topcoat paint N1 of Example 1. The surface tension of the photocurable topcoat paint N1 was 28.7 mN / m. Using the obtained photocurable topcoat paint N1, laminates of test pieces I, II and III described below were prepared and various evaluations were carried out.

<Surface tension of photocurable topcoat paint>
The surface tension of the photocurable topcoat paint was measured by the plate method in an environment of 25°C using a surface tensiometer (CBVP-Z) manufactured by Kyowa Interface Science Co., Ltd.

[Examples 2 to 41], [Comparative Examples 1 to 12]
Photocurable topcoat paints N2 to N41 and N101 to N111 were obtained in the same manner as in Example 1 according to the formulations shown in Tables 1 to 5, and laminates of test pieces I, II, and III were prepared for each photocurable topcoat paint, and various evaluations were carried out.

The components in Tables 1 to 5 are as follows:
(Cationically polymerizable compound (A), etc.)
AI: Celloxide 2021P, manufactured by Daicel Corporation, a bifunctional alicyclic epoxy compound.
AII: RD-111, manufactured by Aditya, a bifunctional glycidyl ether.
AIII: Epogose BD(D), manufactured by Yokkaichi Synthetic Co., Ltd., a bifunctional glycidyl ether.
AIV: Aron Oxetane OXT-101, manufactured by Toagosei Co., Ltd., a monofunctional oxetane.
(Polyol (B), etc.)
BI: Excenol 420: manufactured by AGC, a polyether polyol having two hydroxyl groups and a number average molecular weight of about 400.
BII: Excenol 1030, manufactured by AGC, a polyether polyol having three hydroxyl groups and a number average molecular weight of approximately 1,000.
BIII: Sannix GP-400, manufactured by Sanyo Chemical Industries, Ltd., a polyether polyol having three hydroxyl groups and a number average molecular weight of approximately 400.
BIV: Excenol 2020, manufactured by AGC, a polyether polyol having two hydroxyl groups and a number average molecular weight of approximately 2,000.
BV: Excenol 3020, manufactured by AGC, a polyether polyol having two hydroxyl groups and a number average molecular weight of approximately 3,000.
BVI: K-Flex A-308, manufactured by King Chemical, a polyester polyol having two hydroxyl groups and a number average molecular weight of approximately 600.
BVII: K-Flex 188, manufactured by King Chemical, a polyester polyol having two hydroxyl groups and a number average molecular weight of about 500.
(Cationic Photopolymerization Initiator (C))
・CI: AT-6992, manufactured by Aceto, Triarylsulfonium Hexafluorophosphate Salts, (active ingredient 60%).
CII: AT-6976, manufactured by Aceto, Triarylsulfonium Hexafluoroantimonate Salts, (active ingredient 60%).
(Radical polymerizable monomer (D), etc.)
DI: Miramer M3130 (trimethylolpropane ethyleneoxy-modified triacrylate), manufactured by Miwon.
DII: Visocat #295 (trimethylolpropane triacrylate), manufactured by Osaka Organic Chemicals Co., Ltd. DIII: Aronix M-315 (isocyanuric acid ethyleneoxy-modified tri(meth)acrylate), manufactured by Toagosei Co., Ltd.
DIV: KAYARAD DPHA (dipentaerythritol hexaacrylate): manufactured by Nippon Kayaku Co., Ltd. (radical photopolymerization initiator (E))
EI: Omnirad 1173 (active ingredient 100%) 2-hydroxy-2-methyl-1-phenyl-propan-1-one, manufactured by IGM. EII: Omnirad 184 (active ingredient 100%) 1-hydroxy-cyclohexyl phenyl ketone, manufactured by IGM (polydimethylsiloxane leveling agent (F)
FI: BYK377 (100% active ingredient), manufactured by BYK Corporation, polyether-modified polydimethylsiloxane (containing hydroxyl groups)
FII: BYK-UV3500 (100% active ingredient), manufactured by BYK, polyether-modified polydimethylsiloxane (containing acryloyl groups)
FIII: BYK333 (100% active ingredient), manufactured by BYK Corporation, polyether-modified polydimethylsiloxane (containing neither hydroxyl nor acryloyl groups)
(Silver compound (G))
GI: Novalon AGT330 (silver ion-supported zeolite), manufactured by Toagosei Co., Ltd. GII: Produced using silver ion-supported molybdenum oxide, sodium molybdate dihydrate (Kanto Chemical Co., Ltd.), and silver nitrate (Kanto Chemical Co., Ltd.) GIII: Zeomic AJ10N (silver ion-supported zeolite), manufactured by Sinanen Zeomic Co., Ltd. GIV: AIS-NAZ320 (silver ion-supported silicate), manufactured by JGC Catalysts and Chemicals Co., Ltd.

[Preparation of Test Piece I (Laminate Composed of Metal Substrate/Undercoat Coating Film 1/Topcoat Coating Film)]
Primer 1 ("S48-1281" (containing polyester resin and amino resin), manufactured by Toyochem Co., Ltd.) was applied to a tin plate having a thickness of 0.24 mm and heated at 180°C for 10 minutes to obtain primer coating film ¹ with a coating amount of 20 mg/dm².

Next, the photocurable topcoat paints N1 to N41 and N101 to N111 obtained in Examples 1 to 41 and Comparative Examples 1 to 10 and 12 were applied onto the undercoat film 1, respectively, and irradiated with ultraviolet light under the conditions described below to obtain a topcoat film of ⁷⁰ mg/dm2.
Irradiation conditions: UV irradiation device manufactured by JATEC, high-pressure mercury lamp with an output of 160 W, conveying speed of 25 m/min, cumulative light intensity of UVA band of 100 mJ/cm ² .

The photocurable topcoat paint N110 of Comparative Example 10 did not produce a cured film under the above conditions. Therefore, a laminate was produced under modified conditions, and this laminate was designated Comparative Example 11. Specifically, the process up to coating was the same as in Comparative Example 10, and the photocurable topcoat paint N110 was used, with only the ultraviolet irradiation conditions being changed. The ultraviolet irradiation conditions were changed to a conveying speed of 5 m/min and an integrated light dose of 500 mJ/ ^cm2 .

For each laminate of Test Piece I, the surface free energy, initial curing property, adhesion, and adhesion after processing were evaluated according to the methods described below.

[Preparation of Test Piece II (Laminate consisting of Metal Substrate/Undercoat 1/Ink Layer 1/Topcoat)]

An undercoat film 1 was formed on a 0.24 mm thick tinplate in the same manner as for test piece I. Next, a UV-curable ink 1 ("MDK UV Black M-1", manufactured by Toyo Ink Co., Ltd.) was printed on the undercoat film 1, and the ink was irradiated with ultraviolet light in the UVA band at an integrated light intensity of 100 mJ/ ^cm2 using a 160 W high-pressure mercury lamp at a conveying speed of 25 m/min, thereby obtaining an ink layer ¹ of 20 mg/dm2.

Next, a topcoat film of 70 mg/ ^dm2 was formed on the ink layer 1 using photocurable topcoat paints N1 to N41 and N101 to N111 in the same manner as in the case of test piece I. The surface free energy of each topcoat film is shown in Table 6. Furthermore, as in the case of test piece I, the initial curability, adhesion, and adhesion after processing were evaluated according to the methods described below.

<<Surface free energy of topcoat coating>>
The surface free energy of the topcoat coating film of test piece I of each example and comparative example was determined using a contact angle meter (Drop Master) manufactured by Kyowa Interface Science Co., Ltd. Specifically, the contact angles of water, diiodomethane, and n-hexadecane with the topcoat coating film surface in an environment of 25°C were measured, and the surface free energy was calculated using the Kitazaki-Hata theory (Kitazaki, Hata, Journal of the Adhesion Society of Japan, Vol. 8, No. 3, (1972), etc.).

<<Initial curing properties of topcoat coatings on test pieces I and II>>
Immediately after preparation of each test piece I or II, i.e., immediately after irradiation with ultraviolet light, the surface of the topcoat film of each test piece was touched with a finger, and the time required for the tackiness to disappear was determined. Note that tackiness refers to the degree of stickiness. The evaluation criteria were as follows. From the viewpoint of industrial productivity, a standard of 4.0 or higher is required.
5.0: Tack loss time is less than 3 seconds.
4.5: Tack disappearance time is 3 seconds or more and less than 7 seconds.
4.0: Tack disappearance time is 7 seconds or more and less than 10 seconds.
3.5: Tack disappearance time is 10 seconds or more and less than 15 seconds.
3.0: Tack disappearance time is 15 seconds or more and less than 20 seconds.
2.5: Tack disappearance time is 20 seconds or more and less than 25 seconds.
2.0: Tack disappearance time is 25 seconds or more and less than 30 seconds.
1.5: Tack disappearance time is 30 seconds or more and less than 60 seconds.
1.0: The tackiness of the coating surface does not disappear even after 60 seconds or more.

<<Adhesion of topcoat film on test pieces I and II>>
After 3 minutes or more had passed since the preparation of each of the test specimens I and II (3 minutes or more had passed since the ultraviolet irradiation), 25 grid-like notches were made at 2 mm intervals on the topcoat coating surface of each test specimen. Cellophane tape was applied to the entire grid, and then a first peel test was conducted in which the cellophane tape was peeled off. Subsequently, new cellophane tape was applied to the same location on this sample, and a second peel test was conducted. After the two peel tests, the total peeled area (%) was calculated and evaluated according to the following criteria. In practical use, a standard of 4.0 or higher is required. LP-18 cellophane tape manufactured by Nichiban Co., Ltd. was used.
5.0:0% (no peeling).
4.5: Peeled area is less than 10%.
4.0: Peeled area is 10% or more and less than 20%.
3.5: Peeled area is 20% or more and less than 30%.
3.0: Peeled area is 30% or more and less than 40%.
2.5: Peeled area is 40% or more and less than 50%.
2.0: Peeled area is 50% or more and less than 60%.
1.5: Peeled area is 60% or more and less than 70%.
1.0: Peeled area is 70% or more.

<<Adhesion of topcoat film after processing on test pieces I and II>>
Each test piece I and II was subjected to processing by dropping an impact core onto the backside of a tinplate so that the topcoat surface was convexly processed, thereby obtaining a test sample. Specifically, processing was performed using a Dupont impact tester under the following conditions: the radius of the impact core tip was 1/2 inch, the drop height was 50 cm, and the mass of the drop weight was 300 g. A peel test was then performed twice on the topcoat surface of the processed portion of each test sample, in which cellophane tape was applied and peeled off. Note that the cellophane tape was applied and peeled off from the same location. After the two tests, the total peeled area (%) was calculated and evaluated according to the following criteria. For practical purposes, a standard of 4.0 or higher is required.
5.0:0% (no peeling).
4.5: Peeled area is less than 10%.
4.0: Peeled area is 10% or more and less than 20%.
3.5: Peeled area is 20% or more and less than 30%.
3.0: Peeled area is 30% or more and less than 40%.
2.5: Peeled area is 40% or more and less than 50%.
2.0: Peeled area is 50% or more and less than 60%.
1.5: Peeled area is 60% or more and less than 70%.
1.0: Peeled area is 70% or more.

<<Antibacterial properties of the topcoat coating film of test piece I>>
The antibacterial properties of each test piece I sample were tested in accordance with the test method of JIS Z2801.
A: Antibacterial activity value of 3 or more B: Antibacterial activity value of 2 or more but less than 3 C: Antibacterial activity value of less than 2

<<Antiviral properties of the topcoat coating of test piece I>>
The antiviral properties of each test piece I sample were tested in accordance with the test method of JIS L1922.
A: Antiviral activity value of 3 or more B: Antiviral activity value of 2 or more but less than 3 C: Antiviral activity value of less than 2

[Preparation of Test Piece III (Test Piece Having Protective Coating Film 1 Formed on a Laminate Consisting of Metal Substrate/Undercoat Coating Film 1/Ink Layer 1/Topcoat Coating Film)]
A laminate consisting of metal substrate/undercoat film 1/ink layer 1/topcoat film was prepared using the same procedure as for test piece II. Next, a protective coating "HX75-10R" (manufactured by Toyochem Co., Ltd.) was applied to the topcoat film of this laminate using a bar coater #14, and the state of the coating was observed after 1 minute. The coverage rate of the protective coating relative to the painted area was calculated and evaluated according to the following criteria. For practical purposes, a rating of 4.0 or higher is required.

5.0: The protective paint is not repelled and the painted area is 100% covered with paint.
4.5: The coverage rate of the protective coating is 90% or more but less than 100%.
4.0: The coverage rate of the protective coating is 80% or more but less than 90%.
3.5: The coverage rate of the protective coating is 70% or more but less than 80%.
3.0: The coverage rate of the protective coating is 60% or more but less than 70%.
2.5: The coverage rate of the protective coating is 50% or more but less than 60%.
2.0: The coverage rate of the protective coating is 40% or more but less than 50%.
1.5: The coverage rate of the protective coating is 30% or more but less than 40%.
1.0: Coverage of protective paint is less than 30%.

The evaluation results for each example and comparative example are shown in Tables 6 and 7.

[Examples 42 to 44]
The following test pieces IV, V, and VI were prepared using the antibacterial photocurable topcoat paints N3, 12, and 16. The various physical properties of the topcoat films were evaluated in the same manner as for test pieces I, II, and III.

[Preparation of Test Piece IV (Laminate Composed of Metal Substrate/Undercoat Coating Film 2/Topcoat Coating Film)]
Test piece IV (a laminate consisting of metal substrate/undercoat film 2/topcoat film) was obtained in the same manner as test piece I, except that undercoat film 1 was replaced with undercoat film 2 ("ZE-1500" (a white paint containing polyester resin and amino resin), manufactured by Toyo Printing Inks), the heat drying time was changed to 170°C for ¹² minutes, and the coating weight of the undercoat paint was changed to 150 mg/dm2.

[Preparation of Test Piece V (Laminate Composed of Metal Substrate/Undercoat Film 2/Ink Layer 1/Topcoat Film)]
An undercoat film 2 was formed on a 0.24 mm thick tinplate in the same manner as for Test Piece IV. Next, a UV-curable ink 1 was printed on the undercoat film 2 under the same conditions as for Test Piece II to obtain an ink layer ¹ of 20 mg/dm². Then, the photocurable topcoat paints of each Example and Comparative Example were applied to this ink layer 1, and cured by irradiating with ultraviolet light under the same conditions as for Test Piece I to obtain Test Piece IV (laminate) having a topcoat film. The obtained Test Piece IV was evaluated in the same manner as for Test Piece II.

[Preparation of Test Piece VI (Laminate Composed of Metal Substrate/Undercoat Film 1/Ink Layer 2/Topcoat Film)]
Test piece VI (laminate) having an ink layer 2 of 20 mg/dm2 was prepared in the same manner as test piece II, except that the ink layer 2 was formed using a thermosetting ink 2 ("CPA-97 India ink" manufactured by Matsui Kagaku Co., Ltd.) instead of the UV-curable ink layer ¹ , and the ink layer 2 was cured by heating (heating at 160°C for 10 minutes) instead of by ultraviolet irradiation.

Table 8 shows the results of evaluations of the initial cure, adhesion, and processing adhesion for test pieces IV to VI formed using antibacterial light-curing topcoats N3, N12, and N16.

Comparative Example 1, which contains a high content of radical polymerizable monomer, exhibits poor curing properties. Comparative Example 9, which does not contain polyol (B), also exhibits problems with processing adhesion. Similarly, Comparative Examples 10 and 11, which contain a low amount of cationic photopolymerization initiator (C), also exhibit problems with curing properties and processing adhesion. Comparative Example 12, which does not contain silver-based compound (G), also exhibits neither antibacterial nor antiviral properties. On the other hand, the antibacterial photocurable topcoat paint of this example exhibits excellent curing properties, excellent adhesion to underlying layers (undercoat film, ink layer, etc.), excellent processing adhesion, and antibacterial properties, even when irradiated with a low exposure dose.

The antibacterial photocurable topcoat of the present invention has excellent adhesion to underlayers (primer coatings, ink layers, etc.) made of various materials, making it suitable for a wide range of applications where a topcoat film must be formed on a surface to be coated. For example, it is suitable as a photocurable topcoat for forming a topcoat film on artistic cans with printed metal substrates for storing sweets or tea, beverage cans such as beer cans, coffee cans, and fruit drink cans, food cans for fish, meat, and simmered foods, powdered milk cans, and spray cans.

10: laminate,
20: Metal substrate, 21: Uncoated area, 22: Outer surface side, 23: Inner surface side,
30: primer coating film, 31: first primer coating film, 32: second primer coating film,
40: ink layer, 41: first ink layer, 42: second ink layer,
50: Top coat film,
60: packaging container member, 61: seam, 62: protective coating film,
70: packaging container, 71: main body, 72: can body, 73: bottom member, 74: joint, 75: lid.

Claims (15)

a cationically polymerizable compound (A) having an epoxy group;
a polyol (B) which is a polyether polyol or polyester polyol having two or three hydroxyl groups in one molecule and having a number average molecular weight of 400 or more and 2,000 or less;
a cationic photopolymerization initiator (C);
a radical polymerizable monomer (D) having only trifunctional (meth)acryloyl groups;
a radical photopolymerization initiator (E);
Contains a polydimethylsiloxane-based leveling agent (F) and a silver-based compound (G),
the content of the radical polymerizable monomer (D) is 5 to 35% by mass relative to 100% by mass of the total of the cationically polymerizable compound (A), the polyol (B), and the radical polymerizable monomer (D);
the content of the cationic photopolymerization initiator (C) is 3 to 15 parts by mass relative to 100 parts by mass in total of the cationic polymerizable compound (A) and the polyol (B);
the content of the radical photopolymerization initiator (E) is 1 to 10 parts by mass relative to 100 parts by mass of the radical polymerizable monomer (D);
and the antibacterial activity value of the cured coating film according to JIS Z2801 is 2 or more.
Antibacterial light-curing topcoat paint. The antibacterial photocurable topcoat paint according to claim 1, wherein the cured coating film has an antiviral activity value according to JIS L1922 of 2 or higher. The antibacterial photocurable topcoat paint according to claim 1 or 2, having a surface tension of 29 mN/m or less. A laminate comprising a metal substrate, an undercoat film, an ink layer, and a topcoat film in this order, wherein the topcoat film is a cured product of the antibacterial photocurable topcoat paint described in any one of claims 1 to 3. The laminate according to claim 4, wherein the surface free energy of the topcoat coating film is 25 mJ/ ^m2 or more. A packaging container member comprising the laminate according to claim 4 or 5 in the form of a cylindrical body, the outer surface of the cylindrical body being coated with the topcoat coating film, and the cylindrical body having a seam. The packaging container member according to claim 6, wherein a protective coating is applied to the seam on the outer surface of the cylindrical body. The packaging container member according to claim 6 or 7, further comprising a bottom member that closes the lower opening of the cylindrical body. 6. An integrally molded article formed from the laminate according to claim 4 or 5, wherein the inner surface side is concave due to the peripheral wall portion and the bottom surface portion,
A packaging container member, wherein the outer surface of the integrally molded product is the topcoat coating film. A packaging container comprising a container body having the packaging container member according to claim 8 or 9, and a lid member attached to the container body to cover the opening of the container body. A primer coating is formed on the metal substrate,
forming an ink layer on the undercoat film;
A method for producing a laminate, comprising applying the antibacterial photocurable topcoat paint according to any one of claims 1 to 3 onto the ink layer and curing it to form a topcoat film. The method for producing a laminate according to claim 11, wherein the step of curing the antibacterial photocurable topcoat coating is carried out by irradiating the antibacterial photocurable topcoat coating with light in a wavelength range of 320 nm or more and 390 nm or less so that the integrated light amount is 200 mJ/ ^cm2 or less. A primer coating is formed on the metal substrate,
forming an ink layer on the undercoat film;
an antibacterial photocurable topcoat paint according to any one of claims 1 to 3 is applied onto the ink layer and cured to form a topcoat film, thereby obtaining a laminate;
Using the laminate, a cylindrical body is formed, the outer surface of which is the topcoat coating film, and the peripheral wall portion includes a seam;
A method for manufacturing a packaging container member, comprising a step of covering the joint on the outer surface of the cylindrical body with a protective coating film. A primer coating is formed on the metal substrate,
forming an ink layer on the undercoat film;
an antibacterial photocurable topcoat paint according to any one of claims 1 to 3 is applied onto the ink layer and cured to form a topcoat film, thereby obtaining a laminate;
A method for manufacturing a packaging container member, comprising a step of using the laminate to form an integrally molded product whose inner surface is concave due to the peripheral wall portion and the bottom surface portion, and whose outer surface is the topcoat coating film. The method for manufacturing a packaging container member according to claim 13 or 14, wherein the step of curing the antibacterial photocurable topcoat paint is carried out by irradiating the antibacterial photocurable topcoat paint with light in a wavelength range of 320 nm or more and 390 nm or less so that the integrated light amount is 200 mJ/ ^cm2 or less.