JP6966014B1 - Photo-curable topcoat paint, laminate and its manufacturing method, packaging container member and its manufacturing method, and packaging container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a topcoat coating film having excellent adhesion to a layer (undercoat coating film, ink layer, etc.) arranged under the layer and also having excellent adhesion after processing even when cured with a low exposure amount. Provided are a photocurable topcoat paint that can be formed, a laminate and a method for producing the same, a member for a packaging container and a method for producing the same, and a packaging container. The present invention comprises a cationically polymerizable compound (A) having an epoxy group and a polyether polyol (B) having two or three hydroxyl groups in one molecule and having a number average molecular weight of 2000 or less. , A cationic photopolymerization initiator (C), a trifunctional radically polymerizable monomer (D), a radical photopolymerization initiator (E), and a polydimethylsiloxane-based leveling agent (F). Regarding photocurable topcoats contained in quantity. [Selection diagram] Fig. 2

Description

The present invention relates to a photocurable topcoat. The present invention also relates to a laminate provided with a topcoat coating film, which is a cured product of the photocurable topcoat coating, and a method for producing the same. Further, the present invention relates to a packaging container member including the laminate, a method for manufacturing the same, and a packaging container having the packaging container member.

Since the photocurable composition is polymerized and crosslinked by active light such as ultraviolet rays to exhibit photocurability, a heating step is basically unnecessary and the photocurable composition is excellent in productivity. For this reason, it is particularly useful for adherends that cannot be heated, and is widely used for various purposes.

For example, Patent Document 1 discloses a photocurable resin composition that can be suitably used for optical three-dimensional modeling. Specifically, it contains a cationically 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 in one molecule. Therefore, a photocurable resin composition has been proposed, wherein 60% by mass or more of the ethylenically unsaturated monomer is a polyfunctional monomer having three or more ethylenically unsaturated bonds in one molecule. .. Further, Patent Document 2 discloses an active photocurable composition containing an acrylic compound, an alicyclic epoxy compound, and a curing catalyst, which can be suitably applied as a film for hard coating.

The photocurable composition is also used as a top coat for art cans containing confectionery and tea leaves, aerosol cans for insecticides, and metal cans such as pull-top cans. The topcoat film functions as a topcoat layer that protects a pattern or the like composed of an ink layer applied to the surface of a metal can. There are three-piece type and two-piece type of such metal cans.
In the 3-piece type can body, an undercoat layer, an ink layer, and a topcoat coating film are sequentially formed on a flat metal plate to prepare a can of quadrilateral small pieces from the coated metal plate, and the quadrilateral small pieces are produced. Is rolled into a tubular shape so that the topcoat coating film faces outward, and the overlapped ends are joined to each other to produce the product. Both ends of the can body of the manufactured tubular body are open. A bottom member is attached to one open end of the tubular can body, and a lid member for taking out the contents after accommodating the contents is attached to the other open end to form a packaging container. ..

The two-piece type can body further includes a type in which a topcoat coating film and the like are formed before processing the metal plate and a type in which a topcoat layer and the like are formed after the metal plate is processed.
In the former two-piece type can body, an undercoat layer, an ink layer, and a topcoat coating film are sequentially formed on a flat metal plate, and then a small piece for one can is prepared from the coated metal plate, and the small piece is coated with the topcoat. It is molded so that the coating film or the like is on the outer surface side of the container, and is manufactured as a cup-shaped member in which the peripheral wall portion (also referred to as the side surface portion) and the bottom surface portion are integrated (hereinafter, "precoating". It is sometimes called a "post-molded" two-piece type). The shape of the small piece can be selected according to the shape of the container to be manufactured.
For the latter two-piece type can body, first, a small piece for one can is made from a flat metal plate. Next, the small piece is molded into a cup shape in which the peripheral wall portion (side surface portion) and the bottom surface portion are integrated, and then processed so as to increase the height of the peripheral wall portion (side surface portion) as necessary. It is manufactured by sequentially forming an undercoat layer, an ink layer, and a topcoat coating film on the outer surface side of the peripheral wall portion (side surface portion) (hereinafter, it may be referred to as a "premolding / postcoating" two-piece type). The shape of the small piece can be selected according to the shape of the container to be manufactured.
One end of the manufactured two-piece type can body is open. A lid member for taking out the contents after accommodating the contents is attached to the opening end to form a packaging container.

In addition, a bottom member may be attached to one opening end of a 3-piece type cylindrical can body, and a relatively shallow 2-piece type member may be combined as a lid member at one opening end to form a packaging container. be. FIG. 7 shows a schematic perspective view of such a packaging container. The main body 71 of the packaging container 70 is composed of two parts, and the lid 75 is composed of one part. The main body 71 has a cylindrical can body 72 formed by forming a flat plate-shaped painted metal plate into a cylinder and joining joints 74, and a bottom member attached to one open end of the can body 72. 73. The lid 75 is formed by three-dimensionally processing the top surface and the side surface from a flat plate-shaped painted metal plate with one part, and is configured to be openable and closable with respect to the main body 71.

The mainstream of the can body of art cans is the 3-piece type. The mainstream of pull-top canned can bodies and art can lid members is a two-piece type of "pre-coating / post-molding". The mainstream of the can body of beverage cans and aluminum aerosol cans is a two-piece type of "pre-molding / post-coating".

Japanese Unexamined Patent Publication No. 09-278811 Japanese Unexamined Patent Publication No. 2016-102193

Since the topcoat coating film used for metal cans has a wide variety of surfaces to be coated (undercoat coating film, ink layer, etc.), it is required to have excellent adhesion to various materials. Further, in the case of the 3-piece method, when joining the can body and the bottom member / lid member, the opening diameter is gradually narrowed at the opening end of the can body, and then the bottom member / lid member is wound. Tightening deformation is added. Also in the case of the two-piece method, when the peripheral wall portion and the lid member are joined, the same deformation is applied to the open end of the peripheral wall portion. Alternatively, from the viewpoint of imparting design and improving strength, the can body portion (peripheral wall portion) may be deformed to form irregularities. A relatively shallow lid member manufactured by the two-piece method is also subjected to the same deformation at the open end. Therefore, there is a long-awaited market for a topcoat coating film that can maintain adhesion even after these deformation processes. Furthermore, in recent years, from the viewpoint of reducing the environmental load, photocurable topcoats having an extremely low solvent content have been attracting attention, and it is desired to develop a technique for reducing the irradiation exposure amount for curing more than before. ing.

In the above, the problems with the photocurable topcoat used for metal cans have been described, but the same problems may occur with the photocurable topcoats in general.

The present invention has been made in view of the above background, and even when cured at a low exposure amount, it has excellent adhesion to the surface to be coated (undercoat film, ink layer, etc.) and adheres after processing. It is an object of the present invention to provide a photocurable topcoat coating material capable of forming a topcoat coating film having excellent properties, a laminate and a method for producing the same, a member for a packaging container and a method for producing the same, and a packaging container.

As a result of diligent studies by the present inventors, they have found that the problems of the present invention can be solved in the following aspects, and have completed the present invention.
[1]: A cationically polymerizable compound (A) having an epoxy group, a polyether polyol (B) having two or three hydroxyl groups in one molecule and having a number average molecular weight of 2000 or less, and cationic light. Polymerization initiator (C) and
It contains a trifunctional radically polymerizable monomer (D), a radical photopolymerization initiator (E), and a polydimethylsiloxane-based leveling agent (F), and a cationically polymerizable compound (A), a polyether polyol (B), and The content of the radically polymerizable monomer (D) is 5 to 35% by mass with respect to the total of 100% by mass of the radically polymerizable monomer (D).
The content of the cationic photopolymerization initiator (C) is 3 to 15 parts by mass with respect to a total of 100 parts by mass of the cationically polymerizable compound (A) and the polyether polyol (B).
A photocurable topcoat coating material in which the content of the radical photopolymerization initiator (E) is 1 to 10 parts by mass with respect to 100 parts by mass of the radically polymerizable monomer (D).
[2]: The photocurable topcoat coating material according to [1], which has a surface tension of 29 mN / m or less.
[3]: A laminate comprising a metal base material, an undercoat coating film, an ink layer, and a topcoat coating film in this order, wherein the topcoat coating film cures the photocurable topcoat coating according to [1] or [2]. A laminated body that is a thing.
[4]: The laminate according to [3], wherein the surface free energy of the topcoat coating film is 25 mJ / m ^{2 or more.}
[5]: A member for a packaging container, wherein the laminate according to [3] or [4] is a tubular body, the outer surface side of the tubular body is the topcoat coating film, and the tubular body has a joint.
[6]: The packaging container member according to [5], wherein a protective coating film is coated on the joint on the outer surface side of the tubular body.
[7]: The packaging container member according to [5] or [6], further having a bottom surface member that closes the lower opening of the tubular body.
[8]: An integrally molded product formed from the laminate according to [3] or [4], the inner surface side of which is concave due to the peripheral wall portion and the bottom surface portion.
A member for a packaging container in which the outer surface of the integrally molded product is the topcoat coating film.
[9]: A packaging container including a container body having the packaging container member according to [7] or [8], and a lid member that covers the opening of the container body and is attached to the container body.
[10]: An undercoat coating film is formed on the metal substrate, and the undercoat film is formed.
An ink layer is formed on the undercoat film to form an ink layer.
A method for producing a laminate, wherein the photocurable topcoat coating according to [1] or [2] is applied onto the ink layer and cured to form a topcoat coating film.
[11]: The step of curing the photocurable topcoat is performed by irradiating the photocurable topcoat so that the integrated light amount of light in the wavelength range of 320 nm or more and 390 nm or less is 200 mJ / cm ² or less, according to [10]. Method of manufacturing a laminate of.
[12]: An undercoat coating film is formed on the metal substrate, and the undercoat film is formed.
An ink layer is formed on the undercoat film to form an ink layer.
The photocurable topcoat coating according to [1] or [2] is applied onto the ink layer and cured to form a topcoat coating film to obtain a laminate.
Using the laminated body, the outer surface side is the topcoat coating film, and a tubular body including a joint is formed on the peripheral wall portion.
A method for manufacturing a member for a packaging container, which comprises a step of coating the joint on the outer surface side of the tubular body with a protective coating film.
[13]: An undercoat coating film is formed on the metal substrate, and the undercoat film is formed.
An ink layer is formed on the undercoat film to form an ink layer.
The photocurable topcoat coating according to [1] or [2] is applied onto the ink layer and cured to form a topcoat coating film to obtain a laminate.
A method for manufacturing a member for a packaging container, which comprises a step of forming an integrally molded product in which the inner surface side is concave due to the peripheral wall portion and the bottom surface portion and the outer surface is the topcoat coating film using the laminated body.
[14]: The curing step of the photocurable topcoat is performed by irradiating the photocurable topcoat so that the integrated light amount of light in the wavelength range of 320 nm or more and 390 nm or less is 200 mJ / cm ² or less, [12] or [13] The method for manufacturing a member for a packaging container according to the above.

According to the present invention, a topcoat coating film having excellent adhesion to a surface to be coated (undercoat film, ink layer, etc.) and also excellent adhesion after processing even when cured at a low exposure amount can be obtained. It has an excellent effect of being able to provide a photocurable topcoat coating film that can be formed, a laminate and a method for producing the same, a member for a packaging container and a method for producing the same, and a packaging container. For example, by irradiating light in the UVA wavelength range (320-390 nm) with an integrated light amount of 200 mJ / cm ² or less, the adhesion to the surface to be coated (undercoat coating, ink layer, etc.) is excellent, and the adhesion after processing is excellent. It is possible to provide a photocurable topcoat coating material capable of forming a topcoat coating film having excellent properties, a laminate and a method for producing the same, a member for a packaging container and a method for producing the same, and a packaging container.

The schematic top view which shows an example of the laminated body which concerns on this embodiment. FIG. 1 is a cross-sectional view of the II-II cut portion of FIG. FIG. 1 is a cross-sectional view of the III-III cut portion of FIG. 1 (a modified example of FIG. 2). The schematic perspective view which shows an example of the member for a packaging container which concerns on this embodiment. FIG. 4 is a partially enlarged explanatory view of a region of V in FIG. The schematic explanatory view of the main part which shows an example of the joining method of the member for a packaging container which concerns on this embodiment. A schematic perspective view showing an example of a metal can in which a container body composed of two parts and a lid member composed of one part are combined.

Hereinafter, the present invention will be described in detail. Needless to say, other embodiments are also included in the scope of the present invention as long as they are consistent with the gist of the present invention. In addition, the numerical range specified by using "~" in the present specification includes the numerical values described before and after "~". Further, in the present specification, "film" and "sheet" shall not be distinguished by thickness. In addition, various components appearing in the present specification may be used independently or in combination of two or more, unless otherwise specified. In addition, the same or equivalent members are designated by the same reference numerals.

[[Photo-curing topcoat]]
The photocurable topcoat coating material (hereinafter, also referred to as “the present coating material”) according to the present embodiment includes a cationically polymerizable compound (A) having an epoxy radical (hereinafter, also referred to as “cationically polymerizable compound (A)”). A polyether polyol (B) having two or three hydroxyl groups in one molecule and having a number average molecular weight of 2000 or less (hereinafter, also referred to as "polyether polyol (B)") and a cationic photopolymerization initiator. (C), a trifunctional radically polymerizable monomer (D) (hereinafter, also referred to as “radical polymerizable monomer (D)”), a radical photopolymerization initiator (E), and a polydimethylsiloxane-based leveling agent (hereinafter, also referred to as “radical polymerizable monomer (D)”). F) (hereinafter, also referred to as "leveling agent (F)") is contained. The content of the radically polymerizable monomer (D) is 5 to 35% by mass with respect to 100% by mass of the total of the cationically polymerizable compound (A), the polyether polyol (B) and the radically polymerizable monomer (D). The content of the cationic photopolymerization initiator (C) is 3 to 15 parts by mass with respect to 100 parts by mass of the total of the cationically polymerizable compound (A) and the polyether polyol (B), and the radical photopolymerization initiator (C). The content of E) is 1 to 10 parts by mass with respect to 100 parts by mass of the radically polymerizable monomer (D).

By applying this paint to the surface to be coated and irradiating it with active light rays, a topcoat coating film, which is a cured product, is formed on the surface to be coated. The topcoat film is a topcoat layer and functions as a finishing varnish. The surface to be coated can be protected by the top coat. Further, when the surface to be coated is printed, the printed surface can be appropriately protected from the time of processing or transporting the surface to be coated, and the adhesion of the printed layer can be improved.

The present paint can be obtained by uniformly mixing each component. The cured product refers to a product obtained by irradiating the present paint with active light and curing it. Examples of active rays include ultraviolet rays, visible light, infrared rays, X-rays, α-rays, β-rays, and γ-rays. Among these, ultraviolet rays and visible rays are preferable, and ultraviolet rays are more preferable, and among these, the UVA wavelength range is preferable in consideration of ease of handling. In the present specification, the UVA wavelength range means a wavelength of 320-390 nm.

The use of this paint is not particularly limited, and the material of the surface to be painted is not particularly limited. This coating material is widely used, for example, as a coating material for a topcoat coating film for coating a surface to be coated in which an intermediate layer such as an undercoat coating film or / and a printed ink layer is formed on a base material. be able to. It may be used for coating directly on the base material.

This paint is particularly suitable as a paint for a top coat of a printed metal can. The production of metal cans is a method of processing a laminate in which a topcoat coating film is formed via an undercoat coating film and an intermediate layer which is an ink layer, that is, the above-mentioned three-piece type method or two-piece type precoating. In addition to work and post-molding, it can be manufactured by pre-molding and post-coating methods.

In general, when a cationically polymerizable component is used as a photopolymerizable component of a coating material, the curing speed for obtaining a coating film is slower than when a radically polymerizable component is used. Here, as a method of increasing the curing speed, there is a method of increasing the amount of the cationic photopolymerization initiator (C). However, if the amount of the initiator is too large, the surface layer cures rapidly, while the deeper the layer, the more the cationic photopolymerization initiator (C) relatively contained in the coating film of the upper layer becomes. Light is absorbed and it becomes difficult for sufficient light to reach the deep layer, so that uniform curability is hindered. Further, when a cationically polymerizable component is used, an ^{integrated light amount of 250 mJ / cm 2} (UVA wavelength range) or more is ^{usually required, and in some cases, an integrated light amount of about 1 J / cm 2} (UVA wavelength range) is required. Become. On the other hand, the radically polymerizable component generally has a high curing speed, but since it has a large curing shrinkage, it tends to be hard and brittle, and its adhesion tends to be lower than that of the cationically polymerizable compound (A).

According to this coating film, the above composition in which a cationically polymerizable component and a radically polymerizable component are used in combination and combined with a leveling agent (F) has excellent curability even when cured at a low exposure amount. Therefore, it is possible to provide a photocurable topcoat coating material capable of forming a topcoat coating film having excellent adhesion to a surface to be coated (undercoat coating film, ink layer, etc.) and also excellent adhesion after processing. A cationically polymerizable compound (A) having an epoxy group and a polyether polyol (B) having 2 or 3 hydroxyl groups in one molecule and having a molecular weight of 2000 or less are used as a cationic component, and a specific content of 3 is used. By combining the functional radically polymerizable monomer (D) as a radical component, it is possible to cure at a low exposure amount, and the curing speed and curing shrinkage can be appropriately controlled. In particular, the present paint is suitable for irradiating light in the UVA wavelength range with an integrated light amount of 200 mJ / cm ^{2 or less.}

Further, by combining the leveling agent (F) and the above-mentioned components, the adhesion to the surface to be coated (undercoat film, ink layer, etc.) can be remarkably improved. 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 improve the adhesion after processing while suppressing curing inhibition. A photocurable topcoat can be provided.
Although the present paint can be suitably used for a low exposure amount, it does not exclude the irradiation of the present paint with a high exposure amount. Hereinafter, each component of the present paint will be described in detail.

[Cation-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. And it means a compound that polymerizes or crosslinks with a cation. It is preferable to use 60 to 100% by mass of the cationically polymerizable compound (A) having two or more epoxy groups in 100% by mass of the cationically polymerizable compound (A). From the viewpoint of effectively suppressing curing shrinkage, it is more preferable to use 60 to 100% by mass of the cationically polymerizable compound (A) having two epoxy groups in 100% by 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 an alicyclic epoxy compound (a1)) and glycidyl. Examples thereof include a cationically polymerizable compound (a2) having an ether group (hereinafter, also referred to as “compound (a2)” or a compound (a2) having a glycidyl ether group).

As the cationically polymerizable compound (A), it is preferable to use the alicyclic epoxy compound (a1) from the viewpoint of reducing the curing shrinkage and making the curing speed appropriate, but from the viewpoint of further improving the processing adhesion. Therefore, it is preferable to use the compound (a2) having a glycidyl ether group in combination. By using the compound (a1) having high reactivity and the compound (a2) having lower reactivity than (a1) in combination, the balance between the curing rate, the curing shrinkage and the processing adhesion can be easily adjusted. Further, it is possible to improve the coatability by adjusting the viscosity with the compound (a2) while obtaining excellent film forming property by using the compound (a1). A more preferable combination of the compound (a1) and the compound (a2) includes a combination of a cationically polymerizable compound having a bifunctional alicyclic epoxy group and a cationically polymerizable compound having a bifunctional glycidyl ether group. Be done.

The total content of the compound (a1) and the compound (a2) is preferably 60 to 100% by mass in 100% by mass of the cationically polymerizable compound (A). Further, it is preferable that the mass ratio of the compound (a1) and the compound (a2) is in the range of 100: 0 to 60:40 from the viewpoint of curing rate and reduction of curing shrinkage. Further, it is more preferable that the mass ratio of the compound (a1) and the compound (a2) is in the range of 90: 10 to 65:35 from the viewpoint of processing adhesion. The alicyclic epoxy group refers to a group forming 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.

Examples of the alicyclic epoxy compound (a1) include 4-vinylcyclohexene monoepoxyside, norbornene monoepoxyside, limonene monoepoxyside, limonen dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis-. (3,4-Epoxycyclohexylmethyl) adipate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexanone-meth-dioxane, 3,4-epoxycyclohexylmethylmethacrylate, etc. Can be mentioned.
Examples of commercially available products include celoxide 2021P, celoxide 2081, celoxide 2000, cyclomer M100, and Epolide 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, and polyethylene glycol diglycidyl ether. , Neopentyl glucol 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 type diglycidyl ether, bisphenol F type diglycidyl ether, brominated bisphenol A type diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A type diglycidyl ether, 1,4- Bis [(oxylan-2-ylmethoxy) methyl] cyclohexane and the like can be mentioned.
Commercially available products include Rikaresin HBE-100, Rikaresin DME-100, Rikaresin L-200, Rikaresin BPO-20E, Rikaresin BEO-60E (all manufactured by Shin Nihon Rika Co., Ltd.) Denacol EX-121, Denacol EX-141, and Denacol EX. -145, Denacol EX-212, Denacol EX-211, Denacol EX-201, Denacol EX-252, Denacol EX-850, Denacol EX-851, Denacol EX-612, Denacol EX-313, Denacol EX-314, Denacol EX Examples thereof include -421, Denacol EX-321, Denacol EX-321L, and Denacol EX-411 (all manufactured by Nagase ChemteX Corporation).

With respect to 100% by mass of the cationically polymerizable compound (A), the polyether polyol (B), the cationic photopolymerization initiator (C), the trifunctional radically polymerizable monomer (D) and the radical photopolymerization initiator (E). From the viewpoint of ensuring / improving adhesion and processability, it is preferable that the cationically polymerizable compound (A) is contained in an amount of 50 to 85% by mass. A more preferable range is 55 to 75% by mass.

[Polyester polyol (B)]
The polyether polyol (B) is a compound having two or three hydroxyl groups in one molecule and having a number average molecular weight (hereinafter, the number average molecular weight is abbreviated as Mn) of 2000 or less. It can be appropriately selected from conventionally known polyether polyols. By using a polyether polyol (B) having 2 or 3 hydroxyl groups in one molecule, the processing adhesion can be enhanced.

Examples of the polyether polyol (B) include a reaction product obtained by addition-polymerizing one or more kinds of oxylan compounds using a compound having two or three hydroxyl groups in one molecule as an initiator. Compounds having two or three hydroxyl groups in one molecule include ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, and trimethylolpropane. Etc. can be exemplified. Examples of the oxylan compound 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 (B) is preferably a polyoxyalkylene polyol having an alkyleneoxy group. Preferable 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 and the like. Of these, EO-modified trimethylolpropane, PO-modified trimethylolpropane, EO-modified glycerin, PO-modified glycerin, polyethylene glycol, polypropylene glycol, and polyoxypropylene glyceryl ether are preferable.
The EO modification and PO modification mean (poly) alkylene oxide modification such as ethylene oxide modification and propylene oxide modification, and refer to the addition of a (poly) alkylene oxide unit.

By setting the Mn of the polyether polyol (B) to 2000 or less, the dispersibility in the present coating material can be enhanced and the processing adhesion can be further improved. It is more preferably 1700 or less, still more preferably 1500 or less. The lower limit of the molecular weight of the polyether polyol (B) is not particularly limited, but from the viewpoint of enhancing the curability, 100 or more is preferable, 200 or more is more preferable, and 300 or more is further preferable.

Commercially available products of polyether polyol (B) include Sanniks TP-400 (Mn: 400), Sanniks GP-250 (Mn: 250), Sanniks GP-400 (Mn: 400), and Sanniks GP-600. (Mn: 600), Sanniks GP-1000 (Mn: 1000), Sanniks PP-200 (Mn: 200), Sanniks PP-400 (Mn: 450), Sanniks PP-600 (Mn: 600), Sanniks PP-1000 (Mn: 1000), PEG-200 (Mn: 200), PEG-400 (Mn: 400), PEG-600 (Mn: 600), PEG-1000 (Mn: 1000) (above, Sanyo Made by Kasei Kogyo Co., Ltd.), Exenol 430 (Mn: 430), Exenol 1030 (Mn: 1000), Exenol 420 (Mn: 400), Exenol 720 (Mn: 700), Exenol 1020 (Mn: 1000), Exenol 2020 (Mn: Mn) : 2000) (all manufactured by AGC) and the like.

The content of the polyether polyol (B) is preferably 2 parts by mass or more with respect to 100 parts by mass of the cationically polymerizable compound (A) from the viewpoint of making the effect of processing adhesion more excellent. It is more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more. Further, from the viewpoint of improving the curability, it is preferably 30 parts by mass or less. It is more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less.

The polyether polyol (B) can be used alone or in combination of two or more. The polyether polyol (B) is a compound having two or three hydroxyl groups in one molecule, but the present coating material has one or four hydroxyl groups in one molecule as long as it does not deviate from the gist of the present invention. It does not exclude the inclusion of a polyether polyol having more than one.

[Cationic Photopolymerization Initiator (C)]
The cationic photopolymerization initiator (C) refers to a compound that releases a cation that initiates a polymerization or cross-linking reaction of the cationically polymerizable compound (A) by irradiation with active light.

Various compounds such as diazonium compounds, sulfonium compounds, iodonium compounds, and metal complex compounds are known as cationic photopolymerization initiators (C). Technology application and market ”CMC, published in 1989, p. 78, etc., has a detailed description. Specific examples include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, triphenyliodonium hexafluoroantimonate, diphenyl (4- (phenylthio) phenyl) sulfonium hexafluoroantimonate, and bis (4- (diphenylsul)). Phenyl) phenyl) sulfide bis (hexafluoroantimonate), diphenyl (4- (phenylthio) phenyl) sulfonium hexafluorophosphate, bis (4- (diphenylsulfonio) phenyl) sulfide bis (hexafluorophosphate), etc. Be done. The cationic photopolymerization initiator (C) can be used alone or in combination of two or more.

Examples of commercially available products containing the cationic photopolymerization initiator (C) include CPI-100P (active ingredient 50%), CPI-101A (active ingredient 50%), CPI-200K (active ingredient 50%), and CPI. -110B (100% active ingredient), CPI-310FG (100% active ingredient), CPI-310B (100% active ingredient), CPI-410S (100% active ingredient), CPI-410B (100% active ingredient), IK -1 (100% active ingredient) (above, manufactured by San-Apro), Omnicat250 (75% active ingredient), Omnicat270 (100% active ingredient), Omnicat432 (45% active ingredient) (above, manufactured by IGM), WPI-113 (Active ingredient 50%) (manufactured by Wako Pure Chemical Industries, Ltd.), AT-6992 (active ingredient 60%), AT-6996 (active ingredient 60%) (all manufactured by Aceto).

The content of the cationic photopolymerization initiator (C) is 3 to 15 parts by mass with respect to 100 parts by mass in total of the cationically polymerizable compound (A) and the polyether polyol (B). By using this coating material in this range, a topcoat coating film, which is a cured film having excellent curability even at a low exposure amount, can be obtained. In addition, a coating film having appropriate curing shrinkage and curing speed and excellent adhesion to the surface to be coated can be obtained. Further, a topcoat coating film having excellent adhesion after processing can be obtained. The preferred content of the cationic photopolymerization initiator (C) is 4 to 13 parts by mass, and the more preferable range is 5 to 12 parts by mass.

[Trifunctional radically polymerizable monomer (D)]
The radically polymerizable monomer (D) is a monomer having a trifunctional group that exhibits polymerizable and / or crosslinkability by radicals in one molecule. The presence or absence of other functional groups and the number of functional groups are not limited. The content of the radically polymerizable monomer (D) is 5 to 35% by mass with respect to 100% by mass of the total of the cationically polymerizable compound (A), the polyether polyol (B) and the radically polymerizable monomer (D). .. By setting the content to 5% by mass or more, the adhesion to various surfaces to be coated can be improved. In addition, the adhesion after processing can be improved. Further, by setting the content to 35% by mass or less, the strain at the time of curing can be reduced. A more preferable range is 6 to 32% by mass, and a more preferable range is 7 to 30% by mass.

Preferable examples of the polymerizable group and / and the crosslinkable group of the radically polymerizable monomer (D) include a (meth) acryloyl group and a vinyl group. When a bifunctional radical polymerizable monomer is used, the curability tends to decrease, and when a tetrafunctional or higher functional radical polymerizable monomer is used, the processing adhesion tends to decrease. By using the trifunctional radically polymerizable monomer (D), a coating film having curability, adhesion and adhesion after processing can be obtained. The radically polymerizable monomer (D) is used alone or in combination of two or more. It should be noted that the use of a bifunctional radically polymerizable monomer and a tetrafunctional or higher functional radically polymerizable monomer is not excluded as long as the gist of the present invention is not deviated.

Examples of the radically polymerizable monomer (D) having a (meth) acryloyl group include trimethylolpropane tri (meth) acrylate, trimethylolpropane ethyleneoxy-modified tri (meth) acrylate, and propyleneoxy-modified trimethylolpropane tri (meth) acrylate. Examples thereof include pentaerythritol trimethylolpropane and isocyanurate 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) refers to a compound that emits a radical that initiates a polymerization or cross-linking reaction of the radically polymerizable monomer (D) by irradiation with active light. The content of the radical photopolymerization initiator (E) is 1 to 10 parts by mass with respect to 100 parts by mass of the radically polymerizable monomer (D). Within this range, it is possible to prevent poor curing and obtain an excellent cured film. The radical photopolymerization initiator (E) is not particularly limited, and known radical photopolymerization initiators (E) can be used. Specific examples include benzophenone compounds, dialkoxyacetophenone compounds, α-hydroxyalkylphenone compounds, α-aminoalkylphenone compounds, acylphosphine oxide compounds and the like.

Examples of benzophenone compounds include benzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 4,4'-bis (diethylamino) benzophenone, 4,4'-bis (dimethylamino) benzophenone, and [4- (methylphenylthio) phenyl. ] -Phenylmethanone, methyl benzophenone-2-carboxylate, compounds having two or more benzophenone structures and the like can be mentioned.

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

Examples of α-hydroxyalkylphenone compounds include 1-hydroxy-cyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, and 2-hydroxy-1- [4- (2-hydroxyethoxy). ) -Phenyl] -2-methyl-1-propane-1-one, and the like.

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

Examples of the acylphosphine oxide-based compound 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-based compounds and acylphosphine oxide-based compounds.

Examples of commercially available products include Omnirad 184, 907, 651, 1173, 819, 369E, TPO H (all manufactured by IGM) and the like. The radical photopolymerization initiator (E) is used alone or in combination of two or more.

[Leveling agent (F)]
The leveling agent (F) is a polydimethylsiloxane-based leveling agent as described above. The leveling agent (F) has a function of improving the wettability with the surface to be coated formed under the present coating material and making the topcoat coating film obtained by the present coating material flatter. By using the leveling agent (F), the adhesion to the surface to be coated (intermediate layer such as undercoat film and ink layer) can be adjusted more preferably.

Leveling agents (F) include polyether-modified polydimethylsiloxanes (those that do not have hydroxyl groups and acryloyl groups, those that have hydroxyl groups, those that have acryloyl groups), and polyester-modified polydimethylsiloxanes (those that do not have hydroxyl groups and acryloyl groups). , Those having a hydroxyl group, those having an acryloyl group), those having a polyether ester-modified polydimethylsiloxane (those having no hydroxyl group and an acryloyl group, those having a hydroxyl group, those having an acryloyl group) and the like. The leveling agent (F) is used alone or in combination.

Examples of commercially available leveling agents (F) include BYK333, 377, 378, UV3500, UV3510 (above, manufactured by BYK), TEGO Glide410, 435, 450 (above, manufactured by Evonik) and the like.

The content of the leveling agent (F) can be appropriately selected depending on the type of the surface to be coated or the type of the protective coating film formed on the upper layer. From the viewpoint of maintaining good wettability and permeability to the surface to be coated, the content of the leveling agent (F) is a cationically polymerizable compound (A), a polyether polyol (B), and a cationic photopolymerization initiator ( It is preferably 0.005 part by mass or more with respect to 100 parts by mass of the total of C), the radically polymerizable monomer (D) and the radical photopolymerization initiator (E). It is more preferably 0.01 part by mass or more, and further preferably 0.02 part by mass or more.

As will be described later, a protective coating film may be further formed on the topcoat coating film. In addition, information such as the expiration date may be printed on the topcoat coating film by inkjet printing or the like. For this reason, the topcoat coating film is also required to have excellent adhesion to the upper layer film such as these protective coating films and printing. The content of the leveling agent (F) is cationically polymerizable from the viewpoint of excellent adhesion to the surface to be coated and excellent adhesion to the layer formed on the topcoat coating film. 2 parts by mass with respect to a total of 100 parts by mass of the compound (A), the polyether polyol (B), the cationic photopolymerization initiator (C), the radically polymerizable monomer (D) and the radical photopolymerization initiator (E). The following is preferable. By setting the amount of the leveling agent within this range, there is also an effect of enhancing the dispersibility of the leveling agent (F) in the cured film when the present paint is applied to form a cured film. It is more preferably 1 part by mass or less, and further preferably 0.8 part by mass or less.

<Arbitrary ingredient>
A diluent can be used as an optional component in this coating material. The diluent is not limited, but preferred examples thereof include methylpropylene glycol and propylene carbonate. Further, the present paint may be added with a component that imparts a glossy or matte effect depending on the intended use.
Further, a photosensitizer (polymerization accelerator) may be added to the present coating material as an optional component. Photosensitizers include amine compounds such as triethanolamine, methyldiethanolamine, triethylamine, and diethylamine; thioxanthone, thioxanthone derivatives, anthracene, anthracene derivatives, anthracene, anthracene derivatives, perylene, perylene derivatives, benzophenone, benzoin. Examples thereof include a photosensitizer composed of isopropyl ether and the like.

Further, a cationically polymerizable compound and / or a radically polymerizable monomer other than the above can be added to the present coating material without departing from the spirit of the present invention. Further, a leveling agent other than the leveling agent (F) may be added as long as the gist of the present invention is not deviated. Further, a wettability improver, a surfactant, a plasticizer, an ultraviolet absorber, a silane coupling agent, an inorganic filler, resin particles, a pigment, a dye and the like may be added.

<Surface tension of this paint, surface free energy of topcoat film>
The surface tension of the present coating material can be appropriately adjusted depending on the surface to be coated, and is not particularly limited. From the viewpoint of more effectively enhancing the adhesion to various surfaces to be coated (undercoat film, ink layer, etc.), the surface tension is preferably 29 mN / m or less. It is more preferably 28.5 mN / m or less, and even more preferably 27.5 mN / m or less. The surface tension can be adjusted by a method of adjusting the type and amount of the leveling agent (F), a method of adjusting the type of diluent and the amount of addition, and the like. The lower limit of the surface tension is not particularly limited, but is usually 20 mN / m or more.

Further, the surface free energy of the topcoat coating film cured by applying this paint and being cured by light irradiation can be appropriately adjusted, and is not particularly limited, but from the viewpoint of improving the adhesion with the above-mentioned upper layer film. It is preferable that the temperature is 25 mJ / m ^{2 or more.} It is more preferably 26.5 mJ / m ² or more, and even more preferably 28 mJ / m ² or more. The surface free energy of the topcoat coating film can be adjusted by a method of adjusting the type and amount of the leveling agent (F), a method of adjusting the type and amount of wax added, and the like. The upper limit of the surface free energy is not particularly limited, but is usually 60 mJ / m ² or less.

When the surface tension of this paint is 29 mN / m or less and the surface free energy of the topcoat film is 25 mJ / m ² or more, the topcoat is more effectively improved in adhesion to the undercoat and the ink layer. It is possible to dramatically increase the choice of materials to be formed on the coating film.

[[Laminate and its manufacturing method]]
The laminate according to the present embodiment (hereinafter, also referred to as “the present laminate”) has at least a base material and a topcoat coating film formed on the base material. This topcoat coating is a cured product of the present coating. Examples of the base material include metal, plastic, glass, ceramics, and wood. Any layer such as an undercoat coating film and an intermediate layer such as an ink layer can be formed between the base material and the topcoat coating film.

A schematic top view of an example of this laminated body is shown in FIG. 1, and a cross-sectional view of the II-II cut portion of FIG. 1 is shown in FIG. As shown in FIG. 2, the laminate 10 includes a metal base material 20, an undercoat coating film 30, an ink layer 40, and a topcoat coating film 50 in this order. The topcoat coating film 50 is a topcoat layer as shown in FIG. In the production of the laminate 10, the undercoat coating film 30 is formed on the metal base material 20, the ink layer 40 is formed on the undercoat coating film 30, and the present paint is applied on the undercoat coating film 30 and the ink layer 40. It has a step of forming a topcoat coating film 50 by processing and curing by irradiation with active light.

The integrated light amount for the curing treatment of the topcoat coating film 50 can be appropriately designed. For example, according to this coating film, excellent curing is achieved by irradiating light in a wavelength range of 320 nm or more and 390 nm or less of ^{200 mJ / cm 2 or less.} It is possible to provide a topcoat coating film having properties and having excellent properties. The lower limit of the integrated light amount is not particularly limited as long as it can be cured. For example, it is about 50 mJ / cm ^2.

The laminated body 10 may have another layer. At both ends of the laminated body 10 in the lateral direction (X direction in FIG. 1), the metal base material 20 is exposed in a line along the Y direction, and has uncoated regions 21 which are planned to be joined. The laminated body 10 is joined by superimposing the uncoated regions 21 at both ends on each other to form a packaging container member 60 which is a tubular weld can as shown in FIG. 4 to be described later. By providing the non-coated region 21 in which the metal base material 20 on which the undercoat coating film 30 and the like are not laminated is exposed, it is possible to prevent welding defects when forming a welding can.

The material of the metal base material 20 is not particularly limited, and surface-treated steel sheets such as tin plate, chrome-plated steel plate, aluminum plate, aluminum alloy plate, tin-free steel, aluminum-plated steel plate, nickel-plated steel plate, tin-nickel-plated steel plate, and various types thereof. An example is the alloy-plated steel sheet of. Further, it may 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 base material, the white pigment may be contained in the resin layer to be coated.

The undercoat coating film 30 is configured as one layer as shown in FIG. 2, may be composed of two layers as shown in FIG. 3, or may be composed of three or more layers. As shown in FIG. 3, when the two-layer undercoat coating film 30 is provided, the first undercoat coating film 31 and the first undercoat coating film 30 for convenience are those in which most of the undercoat coating film 30 is in direct contact with the metal substrate 20. For convenience, the coating film further provided on the first undercoat coating film 31 is referred to as the second undercoat coating film 32.

The first undercoat coating film 31 can be formed by a known method. For example, the first undercoat coating film 31 can be formed by applying, drying, and curing the undercoat coating film for the first undercoat coating film on the metal base material 20.
The second undercoat coating film 32 can be formed by applying a coating film for the second undercoat coating film on the first undercoat coating film 31, drying, and curing. The paint for the second undercoat coating film 32 may be directly applied / dried to a part of the metal base material 20 and cured.
As the paint for the first and second undercoat coating films (hereinafter, may be referred to as undercoat paint), a composition in which the binder component is dissolved or dispersed in a solvent can be used. As the binder component, a thermosetting compound and a photocurable compound are suitable. When a binder component containing a thermosetting compound is used, the undercoat paint is applied and dried, and then cured by heat. When a binder component containing a photocurable compound is used, it is cured by irradiating it with active light. A thermosetting compound and a photocurable compound may be used in combination. The undercoat paint can include colorless inorganic fillers and colored pigments. For example, silica can be exemplified as a colorless inorganic filler, and titanium dioxide or the like can be exemplified as a white pigment.

The thickness of the first undercoat coating film 31 and the second undercoat coating film 32 is not particularly limited. The mass per unit area of each coating film can be, for example, 1 to 300 mg / dm ^2. When the main purpose is to conceal the ground color of the metal base material 20, it can be ^{, for example, 40 to 300 mg / dm 2.}

In the example of the laminate 10 of FIG. 3, the ink layer 40 is composed 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 a plurality of layers exceeding two layers. The ink layer 40 can form a pattern or a colored layer on the metal base material. The ink layer 40 may be formed on the entire surface of the undercoat coating film, or may be formed at a desired position as shown in FIG.

The ink layer 40 can be obtained by plate printing such as offset printing or screen printing in which a plurality of plates are produced and multicolor printing is performed, inkjet printing using the liquid suitability of the ink sprayed from the ink head, and the like. Plate printing and inkjet printing may be used together. When the ink layer is composed of multiple layers in plate printing, each layer is cured. Alternatively, each layer may be temporarily cured, and the final curing treatment may be performed after laminating the plurality of layers.

The ink layer 40 is coated with an ink containing, for example, a binder component (a binder component containing a thermosetting compound, a binder component containing an oxidatively polymerizable compound, a binder component containing a photocurable compound, etc.) and a pigment. It is obtained by coating on 30 and curing to form a cured film. A known compound can be used as the binder component used in the ink. For example, alkyd resin, polyester resin, epoxy resin and the like can be mentioned. The pigment may be either an organic pigment or an inorganic pigment. In addition, a curing agent can be added if necessary. Further, a pigment dispersant, a wax, a stabilizer and the like can be added as optional components.

The film thicknesses of the first ink layer 41 and the second ink layer 42 are not limited, but can be, for example, about 0.1 to 6 μm. In the example of FIG. 3, for example, the first ink is applied, dried, and cured on the second undercoat coating film 32 to form the first ink layer 41, and then the second ink is placed at a desired position. The ink layer 40 is obtained by forming the second ink layer 42 by applying, drying, and curing the ink layer 42.

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

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

<Modification example>
As another example of the present laminate, a laminate having a structure in which a metal base material, an undercoat coating film, and a topcoat coating film are laminated in this order, or a laminate having a structure in which a topcoat coating film is directly formed on a metal base material. Can be exemplified. Further, instead of the metal base material, paper, plastic film, wood material, glass, stone material and the like can be used as the base material.

[[Packaging container members and their manufacturing methods]]
The packaging container member according to the present embodiment has a member formed by using the present laminate. FIG. 4 is a schematic perspective view showing an example of the member for the present packaging container, and FIG. 5 is a partially enlarged explanatory view of a cross section of the region V in FIG. In the packaging container member 60, the laminated body is a tubular body, and the outer surface side of the tubular body is a topcoat coating film 50 formed of the present paint. The tubular body has a joint 61. The joint 61 of the packaging container member 60 is a portion joined by superimposing the uncoated regions 21 which are the planned welding portions at both ends of the laminated body 10 in the X direction of FIG. 1 and performing a joining process. A protective coating film 62 is formed on the joint 61 (see FIG. 5) on the outer surface side 22 of the tubular body.

As shown in FIG. 5, the protective coating film 62 is coated from the joint 61 on the outer surface side 22 of the metal base material 20 to the upper surface of the end portion of the adjacent topcoat coating film 50. As a result, the joint 61 can be protected and reinforced, and the aesthetic appeal of the packaging container member can be enhanced. An inner surface protective layer (not shown) may be formed on the inner surface side 23 of the metal base material 20. The protective coating film 62 can be formed by a known method. For example, it can be obtained by applying a protective paint and drying it. Alternatively, it may be a cured film that has been dried and then cured by heat or light. Further, a protective tape may be attached instead of the protective coating film.

In addition to the above method, various known methods such as welding, adhesive, solder, and caulking can be applied to the joining for forming the laminated body 10 into a tubular body. FIG. 6 shows a schematic top view of the crimped portion of the packaging container member joined by caulking. As shown in the figure, the tubular bodies are joined by overlapping, bending, and wrapping both ends of the laminated body 10 in one direction. Of 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 base material 20. In the case of joining by caulking, the undercoat coating film 30, the ink layer 40, and the topcoat coating film 50 are provided on the entire surface of the metal base material 20 without providing the non-coating region 21 (see FIG. 1). You may use the body. Further, in the case of caulking, it is not necessary to provide a protective coating film for covering the joint.

The tubular packaging container member 60 functions as a can body. In the case of manufacturing a three-piece can, a packaging container member (not shown) in which a bottom member for closing the lower opening of the tubular body serving as the can body is joined by welding or the like can be used. It can be suitably used as a member for a canned packaging container or a member for a spray can packaging container.

<Modification example>
As an example of another packaging container member of the present embodiment, a packaging container member formed of an integrally molded product formed of a sheet-shaped main laminated body and recessed by a peripheral wall portion and a bottom surface portion can be exemplified. A topcoat coating film formed by the present paint is formed on the outer surface of this integrally molded product. It can be suitably used as a member for a packaging container of a two-piece can for accommodating foods and the like. Since this laminate uses a topcoat coating film having excellent adhesion after processing, it can be suitably used as a member for a packaging container having such an integrally molded product.
In the above embodiment, an example of forming a metal can using a laminate has been given, but after forming the metal can, the molded metal can is coated with a spray, a roll, or the like to provide a top coat or the like. This paint can also be used for the purpose of forming.

[[Packaging container]]
The packaging container of the present embodiment includes a container main body having the main packaging container member, and a lid member that covers the opening of the container main body and is attached to the container main body. As described above, the container body is a member for a packaging container in which a bottom member that closes a lower opening of a cylindrical body to be a can body is joined by welding or the like, or a tubular peripheral wall portion described in a modified example. An example is a packaging container member whose bottom surface is formed of an integrally molded product. The opening of the container body means an outlet for taking out the contents contained in the container body. The lid member may be a member attached to the container body such as a pull-tab can, or a concave openable / closable lid made of one part described with reference to FIG. 7.

The present invention will be described in more detail, but the following examples do not limit the scope of rights of the present invention. In addition, "part" and "%" in an Example represent "part by mass" and "mass%", respectively.

[Example 1]
The components shown in Table 1 were blended to obtain the photocurable topcoat N1 according to Example 1. In Table 1, the blending amount of each component is parts by mass.
Specifically, as the cationically polymerizable compound (A), a bifunctional alicyclic epoxy compound "Ceroxide 2021P (manufactured by Daicel)": 60.67 parts, and a bifunctional glycidyl ether "RD-". 111 (manufactured by Aditya) ”: 20 parts were used. As the polyether polyol (B), "Excenol 420 (manufactured by AGC)" which is a polyether polyol having two hydroxyl groups and having a number average molecular weight of about 400: 5.5 parts, "AT" having a non-volatile content of 60% by mass. -6992 (manufactured by Aceto) ”: 8 parts (including cationic photopolymerization initiator (C): 4.8 parts) was used. As the radically polymerizable monomer (D), "Miramer M3130 (manufactured by Miwon)" which is a trifunctional radically polymerizable monomer: 5.5 parts, and as the radical photopolymerization initiator (E), the non-volatile content is 100% by mass. 0.3 part of "Omnirad 1173 (manufactured by IGM)" and 0.03 part of "BYK377 (manufactured by BYK)" having a non-volatile content of 100% by mass were used as the leveling agent (F). The surface tension of the photocurable topcoat N1 was 26.8 mN / m. For the obtained photocurable topcoat paint N1, laminates of test pieces I, II, and III, which will be described later, were prepared and evaluated in various ways.

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

[Examples 2 to 30], [Comparative Examples 1 to 11]
According to the formulations shown in Tables 1 to 4, photocurable topcoats N2 to N30 and N101 to N110 were obtained in the same manner as in Example 1. Laminates were prepared and evaluated in various ways.

Each component in Tables 1 to 4 is as follows.
(Cation-polymerizable compound (A), etc.)
-AI: Celoxide 2021P, a bifunctional alicyclic epoxy compound manufactured by Daicel.
-AII: RD-111, made by Aditya, bifunctional glycidyl ether.
-AIII: Epogoose BD (D), a bifunctional glycidyl ether manufactured by Yokkaichi Chemical Company Limited.
-AIV: Aron Oxetane OXT-101, manufactured by Toagosei Co., Ltd., monofunctional oxetane.
(Polyester polyol (B), etc.)
-BI: Excenol420: Made by AGC, a polyether polyol having two hydroxyl groups and having a number average molecular weight of about 400.
-BII: Excenol1030, manufactured by AGC, a polyether polyol having three hydroxyl groups and having a number average molecular weight of about 1000.
-BIII: Sanniks GP-400, manufactured by Sanyo Chemical Industries, Ltd., a polyether polyol having three hydroxyl groups and having a number average molecular weight of about 400.
-BIV: Excenol2020, manufactured by AGC, a polyether polyol having two hydroxyl groups and having a number average molecular weight of about 2000.
-BV: Excenol3020, manufactured by AGC, a polyether polyol having two hydroxyl groups and having a number average molecular weight of about 3000.
(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, trifunctional acrylate (TMP / EO / TA) manufactured by Miwon.
-DII: Visocat # 295, trifunctional acrylate (TMPTA) manufactured by Osaka Organic Co., Ltd.
-DIII: Aronix315, trifunctional acrylate (THEIC-TA) manufactured by Toagosei Co., Ltd.
-DIV: KAYARAD DPHA: A hexafunctional acrylate manufactured by Nippon Kayaku Co., Ltd.
(Radical Photopolymerization Initiator (E))
-EI: Omnirad1173 (100% active ingredient), manufactured by IGM-EII: Omnirad184 (100% active ingredient), manufactured by IGM (polydimethylsiloxane-based leveling agent (F))
・ FI: BYK377 (100% active ingredient), BYK ・ FII: BYK-UV3500 (100% active ingredient), BYK ・ FIII: BYK333 (100% active ingredient), BYK

[Preparation of test piece I (laminate consisting of metal substrate / undercoat film 1 / topcoat film)]
Undercoating agent 1 ("S48-1281" (including polyester resin and amino resin), manufactured by Toyochem Co., Ltd.) is applied to a tin plate having a thickness of 0.24 mm, and heated at 180 ° C. for 10 minutes to obtain a coating film amount. An undercoat film 1 of 20 mg / dm ^{2 was obtained.}

Next, the photocurable topcoats N1 to N30 and N101 to N110 obtained in Examples 1 to 30 and Comparative Examples 1 to 10 were coated on the undercoat coating film 1, respectively, and irradiated with ultraviolet rays under the following conditions to obtain 70 mg. A topcoat film of / dm ^{2 was obtained.}
Irradiation conditions: UV irradiation device manufactured by Jatec, high-pressure mercury lamp with an output of 160 W, transfer speed 25 m / min, integrated light intensity of UVA band 100 mJ / cm ² .

In the photocurable topcoat N110 according to Comparative Example 10, a cured film could not be obtained under the above conditions. Therefore, a laminated body under different conditions was prepared, and this laminated body was designated as Comparative Example 11. Specifically, as the process up to coating, the same process as in Comparative Example 10 and the photocurable topcoat paint N110 were used, and only the ultraviolet irradiation conditions were changed. As for the ultraviolet irradiation conditions, the transport speed was changed to 5 m / min and the integrated light intensity was set to 500 mJ / cm ² .

The surface free energy, initial curability, adhesion, and adhesion after processing were evaluated for each laminate of Test Piece I according to the method described later.

[Preparation of test piece II (laminate consisting of metal substrate / undercoat film 1 / ink layer 1 / topcoat film)]

The undercoat coating film 1 was formed on a tin plate having a thickness of 0.24 mm by the same method as that of the test piece I. Next, UV curable ink 1 (“MDK UV Black M-1”, manufactured by Toyo Ink Co., Ltd.) was printed on the undercoat coating film 1 and used at a transport speed of 25 m / min using a high-pressure mercury lamp with an output of 160 W. Ink layer 1 of ^{20 mg / dm 2} was obtained by irradiating ultraviolet rays in the UVA band with an integrated light amount of 100 mJ / cm ^2.

^{Next, a 70 mg / dm 2} topcoat film was formed on the ink layer 1 using the photocurable topcoats of Examples 1 to 30 and Comparative Examples 1 to 10 by the same method as in the case of Test Piece I. bottom. Table 5 shows the surface free energy of each topcoat film. Further, as in the case of Test Piece I, the initial curability, adhesion and adhesion after processing were evaluated according to the method described later.

<< 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 by a contact angle meter (Drop Master) manufactured by Kyowa Interface Science Co., Ltd. Specifically, the contact angles of water, diiodomethane, and n-hexadecane on the surface of the topcoat coating film in an environment of 25 ° C were measured, and the Kitazaki-Hata theory "Kitasaki, Hata, Journal of the Japan Adhesive Society, Vol.8, No." The surface free energy was calculated using ".3, (1972), etc."

<< Initial curability of topcoat coating film of test pieces I and II >>
Immediately after the preparation of the test pieces I and II, that is, immediately after the irradiation with ultraviolet rays, the surface of the topcoat coating film of each test piece was touched with a finger, and the time required for the tack to disappear was determined. The tack means the degree of stickiness. The evaluation criteria are as follows. From the viewpoint of industrial productivity, a standard of 4.0 or higher is required.
5.0: Tack disappearance 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 tack on the coating film surface does not disappear even after 60 seconds or more.

<< Adhesion of topcoat coating film of test pieces I and II >>
More than 3 minutes have passed since the samples of each test piece I and II were prepared (more than 3 minutes have passed after irradiation with ultraviolet rays). Formed eyes. After the cellophane tape was attached to the entire grid, the first peeling test was performed to peel off the cellophane tape. Subsequently, a new cellophane tape was attached to the same part of this sample, and a second peeling test was performed. After performing the peeling test twice, the total peeled area (%) was calculated and evaluated according to the following criteria. Practically, a standard of 4.0 or higher is required. As the cellophane tape, LP-18 manufactured by Nichiban Co., Ltd. was used.
5.0: 0% (no peeling).
4.5: The peeled area is less than 10%.
4.0: The peeled area is 10% or more and less than 20%.
3.5: The peeled area is 20% or more and less than 30%.
3.0: The peeled area is 30 or more and less than 40%.
2.5: The peeled area is 40% or more and less than 50%.
2.0: The peeled area is 50% or more and less than 60%.
1.5: The peeled area is 60% or more and less than 70%.
1.0: The peeled area is 70% or more.

<< Adhesion after processing of the topcoat coating film of test pieces I and II >>
A test sample was obtained by dropping a striking core on the back surface of the tin plate so that the surface of the topcoat coating film of each test piece I or II was convexly processed. Specifically, using a DuPont impact tester, the processing was performed under the conditions that the radius of the tip of the striking core was 1/2 inch, the drop height was 50 cm, and the mass of the drop weight was 300 g. Then, a peeling test was carried out twice in which a cellophane tape was applied and peeled off on the topcoat coating film surface of the processed portion of this test sample. The place where the cellophane tape was applied and peeled off was the same. After performing twice, the total peeled area (%) was calculated and evaluated according to the following criteria. Practically, a standard of 4.0 or higher is required.
5.0: 0% (no peeling).
4.5: The peeled area is less than 10%.
4.0: The peeled area is 10% or more and less than 20%.
3.5: The peeled area is 20% or more and less than 30%.
3.0: The peeled area is 30 or more and less than 40%.
2.5: The peeled area is 40% or more and less than 50%.
2.0: The peeled area is 50% or more and less than 60%.
1.5: The peeled area is 60% or more and less than 70%.
1.0: The peeled area is 70% or more.

[Preparation of test piece III (test piece in which the protective coating film 1 is formed on a laminate consisting of a metal base material / undercoat coating film 1 / ink layer 1 / topcoat coating film)]
A laminate consisting of a metal base material / undercoat coating film 1 / ink layer 1 / topcoat coating film was prepared in the same procedure as Test Piece II. Next, the protective coating film "HX75-10R" (manufactured by Toyochem Co., Ltd.) was applied onto the topcoat coating film of this laminate using bar coater # 14, and the state of the coating film after 1 minute was observed. The coverage of the protective paint was calculated for the painted area and evaluated according to the following criteria. Practically, a standard 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 of the protective paint is 90% or more and less than 100%.
4.0: The coverage of the protective paint is 80% or more and less than 90%.
3.5: The coverage of the protective paint is 70% or more and less than 80%.
3.0: The coverage of the protective paint is 60% or more and less than 70%.
2.5: The coverage of the protective paint is 50% or more and less than 60%.
2.0: The coverage of the protective paint is 40% or more and less than 50%.
1.5: The coverage of the protective paint is 30% or more and less than 40%.
1.0: The coverage of the protective paint is less than 30%.

The evaluation results of each Example and Comparative Example are shown in Tables 5 and 6.

[Examples 31 to 33]
The following test pieces IV, V, and VI were prepared using the photocurable topcoats N3, 12, and 16 obtained in Examples 3, 12, and 16. Then, various physical properties of the topcoat coating film were evaluated in the same manner as in the cases of the test pieces I, II, and III.

[Preparation of test piece IV (laminate consisting of metal substrate / undercoat film 2 / topcoat film)]
Instead of the undercoating agent 1, the undercoating agent 2 (“ZE-1500” (white paint containing polyester resin and amino resin), manufactured by Toyo Printing Inks) was used, and the heating and drying time was heated at 170 ° C. for 12 minutes. From the test piece IV (metal base material / undercoat film 2 / topcoat film) by the same method as the test piece I, except that the conditions were changed to the above and the amount of the undercoat paint was set to 150 mg / dm ^2. A laminate) was obtained.

[Preparation of test piece V (laminate consisting of metal substrate / undercoat film 2 / ink layer 1 / topcoat film)]
The undercoat coating film 2 was formed on a tin plate having a thickness of 0.24 mm by the same method as that of the test piece IV. Next, the UV curable ink 1 was printed on the undercoat coating film 2 under the same conditions as the test piece II to obtain an ink layer 1 of ^{20 mg / dm 2.} Then, a photocurable topcoat coating material of each Example and Comparative Example is coated on the ink layer 1, and the test piece has a topcoat coating film by irradiating and curing the ink layer 1 with ultraviolet rays under the same conditions as the test piece I. IV (laminated body) was obtained. The obtained test piece IV was evaluated by the same method as that of test piece II.

[Preparation of test piece VI (laminate consisting of metal substrate / undercoat film 1 / ink layer 2 / topcoat film)]
The point that the ink layer 2 was formed by using the heat-curable ink 2 (“CPA-97 ink” manufactured by Matsuikagaku Co., Ltd.) instead of the UV curable ink layer 1, and the ink layer 2 was cured instead of the ultraviolet irradiation. A test piece VI (laminated body) having an ink layer 2 of ^{20 mg / dm 2} was prepared by the same method as the test piece II except that it was heated (heated at 160 ° C. for 10 minutes).

Results of evaluating the initial curability, adhesion, and processing adhesion of each of the test pieces IV to VI according to Examples 17 to 19 formed by the photocurable topcoats N3, N12, and N16 of Examples 3, 12, and 16. Is shown in Table 7.

In Comparative Example 1 in which the content of the radically polymerizable monomer is high, it is confirmed that the curability is inferior. Further, in Comparative Example 9 which does not contain the polyether polyol (B), it can be seen that there is a problem in processing adhesion. Similarly, in Comparative Examples 10 and 11 in which the amount of the cationic photopolymerization initiator (C) is small, it is confirmed that there are problems in curability and processing adhesion. On the other hand, according to the photocurable topcoat coating according to the present embodiment, even when irradiated with a low exposure amount, the curability is excellent, and the layer (undercoat coating film, ink layer, etc.) arranged in the lower layer is used. It can be seen that the adhesion is excellent and the processing adhesion is also excellent.

Since the photocurable topcoat coating material of the present invention has excellent adhesion to underlayers (undercoat coating film, ink layer, etc.) made of various materials, it can be used in a wide range of applications in which a topcoat coating film is desired to be formed on the surface to be coated. Applicable. For example, art cans for storing sweets and tea printed on a metal substrate, beer cans, coffee beverage cans, beverage cans such as fruit beverage cans, food cans such as fish, meat, and simmered foods, spray cans, etc. It is suitable as a photocurable topcoat for forming a topcoat.

10: Laminated body,
20: Metal substrate, 21: Uncoated area, 22: Outer surface side, 23: Inner surface side,
30: Undercoat coating, 31: First undercoat, 32: Second undercoat,
40: Ink layer, 41: First ink layer, 42: Second ink layer,
50: Topcoat coating,
60: Packaging container member, 61: Joint, 62: Protective coating film,
70: Packaging container, 71: Main body, 72: Can body, 73: Bottom member, 74: Joint, 75: Cover.

Claims (14)

A cationically polymerizable compound (A) having an epoxy group and
A polyether polyol (B) having 2 or 3 hydroxyl groups in one molecule and having a number average molecular weight of 2000 or less,
Cationic photopolymerization initiator (C) and
A radically polymerizable monomer (D) having a trifunctional acryloyl group and
Radical photopolymerization initiator (E) and
The radically polymerizable monomer (D) contains a polydimethylsiloxane-based leveling agent (F) with respect to a total of 100% by mass of the cationically polymerizable compound (A), the polyether polyol (B) and the radically polymerizable monomer (D). The content of is 5 to 35% by mass,
The content of the cationic photopolymerization initiator (C) is 3 to 15 parts by mass with respect to a total of 100 parts by mass of the cationically polymerizable compound (A) and the polyether polyol (B).
A photocurable topcoat coating material in which the content of the radical photopolymerization initiator (E) is 1 to 10 parts by mass with respect to 100 parts by mass of the radically polymerizable monomer (D). The photocurable topcoat coating according to claim 1, wherein the surface tension is 29 mN / m or less. A laminate comprising a metal base material, 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 photocurable topcoat coating according to claim 1 or 2. .. The laminate according to claim 3, wherein the surface free energy of the topcoat coating film is 25 mJ / m ^{2 or more.} A member for a packaging container in which the laminate according to claim 3 or 4 is a tubular body, the outer surface side of the tubular body is the topcoat coating film, and the tubular body has a joint. The packaging container member according to claim 5, wherein a protective coating film is coated on the joint on the outer surface side of the tubular body. The packaging container member according to claim 5 or 6, further comprising a bottom surface member that closes the lower opening of the tubular body. An integrally molded product formed from the laminate according to claim 3 or 4, wherein the inner surface side is concave due to the peripheral wall portion and the bottom surface portion.
A member for a packaging container in which 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 7 or 8, and a lid member that covers the opening of the container body and is attached to the container body. An undercoat film is formed on the metal substrate,
An ink layer is formed on the undercoat film to form an ink layer.
A method for producing a laminate, wherein the photocurable topcoat coating according to claim 1 or 2 is applied onto the ink layer and cured to form a topcoat coating film. The step of curing the photocurable topcoat coating is carried out by irradiating the laminate so that the integrated light amount of light in the wavelength range of 320 nm or more and 390 nm or less is 200 mJ / cm ^{2 or less.} Production method. An undercoat film is formed on the metal substrate,
An ink layer is formed on the undercoat film to form an ink layer.
The photocurable topcoat coating according to claim 1 or 2 is applied onto the ink layer and cured to form a topcoat coating film to obtain a laminate.
Using the laminated body, the outer surface side is the topcoat coating film, and a tubular body including a joint is formed on the peripheral wall portion.
A method for manufacturing a member for a packaging container, which comprises a step of coating the joint on the outer surface side of the tubular body with a protective coating film. An undercoat film is formed on the metal substrate,
An ink layer is formed on the undercoat film to form an ink layer.
The photocurable topcoat coating according to claim 1 or 2 is applied onto the ink layer and cured to form a topcoat coating film to obtain a laminate.
A method for manufacturing a member for a packaging container, which comprises a step of forming an integrally molded product in which the inner surface side is concave due to the peripheral wall portion and the bottom surface portion and the outer surface is the topcoat coating film using the laminated body. The packaging according to claim 12 or 13, wherein the curing step of the photocurable topcoat is performed by irradiating the light in a wavelength range of 320 nm or more and 390 nm or less so that the integrated light amount is 200 mJ / cm ^{2 or less.} A method for manufacturing container members.

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