JP2023024109A - Method for manufacturing printed matter - Google Patents

Abstract

To provide a method for manufacturing a printed matter less prone to breakage while maintaining hardness even when a printed layer built up thick is subjected to heat treatment.SOLUTION: A method for manufacturing a printed matter with a clear layer includes: a first step including forming a clear layer by carrying out printing with an active energy ray-curable clear ink on a substrate or a layer formed on the substrate, followed by curing the clear layer, in which the clear ink includes a polymerizable compound and a photoinitiator, and an average function base number of the polymerizable compound in the clear ink is 1.05 to 1.60; and a second step of heating a printed matter including a cured clear layer.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a method for producing a printed matter, and more particularly to a method for producing a printed matter that is resistant to cracking while ensuring hardness even when a thickly raised printed layer is subjected to heat treatment.

In recent years, decoration is performed using active energy ray-curable ink. Since active energy ray-curable inks are cured by irradiation with active energy rays, ejection failures such as nozzle clogging due to volatilization and drying of water and organic solvents can occur, as in the case of conventional organic solvent-based inks and water-based inks. It has the advantage of improving productivity because it is hard to dry and dries quickly.

In addition, a method of inkjet printing using an active energy ray-curable ink on a heat-resistant substrate to obtain a printed matter with excellent design is being studied.

Japanese Patent Application Laid-Open No. 2018-79400 (Patent Document 1) discloses that after coating the surface of a heat-resistant substrate with an undercoat paint, the undercoat film is formed by baking and curing, and then the surface of the undercoat film thus formed. is inkjet printed using an active energy ray-curable ink, and then cured by irradiation with an active energy ray to form a printed layer. Here, by blending an acrylic resin with a specific crosslinkable functional group into the undercoat paint and baking it to form an undercoat film, it can be used on non-absorbing substrates such as metals that do not absorb ink. It is described that a printed layer having good adhesion and excellent design can be formed.

Japanese Patent Application Laid-Open No. 2018-83343 (Patent Document 2) is an invention of a printed matter manufacturing method in which a base layer is printed with an active energy ray-curable ink to form a printed layer, and the printed layer is cured and then heated. wherein an active energy ray-curable ink containing a compound having a specific structure as a monomer having an ethylenically unsaturated group and an underlayer containing a functional group capable of reacting with the compound are used. Therefore, even in a printed layer formed from an active energy ray-curable ink, the portion derived from the compound present in the printed layer and the functional group contained in the underlayer are reacted to form the printed layer and It is described that the interlayer adhesion of the underlayer can be improved.

Japanese Patent Application Laid-Open No. 2018-79400 JP 2018-83343 A

The printed layer described in Patent Documents 1 and 2 is a method for obtaining a printed layer that adheres well to a non-absorbing substrate such as a metal that does not absorb ink and that is excellent in design. The surface protective layer that protects the decorative ink layer has not been sufficiently studied. For example, Patent Literature 2 describes that conventionally known paints and inks can be used to form a surface protective layer that protects a printed layer.

Here, from the viewpoint of solving the problem of odor and stickiness of the ink layer, the surface protective layer formed by the active energy ray-curable ink is used when printing on a heat-resistant substrate. Treatment is desirable. In addition, this can improve the adhesion of the surface protective layer.

The present inventors have studied a method of printing on a heat-resistant substrate such as metal, glass, ceramic, artificial marble, etc., curing the surface protective layer, and then further heating it. However, there is a problem that the surface protective layer cracks or peels off. In recent years, it has been proposed to apply various designs such as gloss, matte, and lenticular to the surface, in addition to protecting the underlying layer, by using a colorless and transparent clear ink layer using active energy ray-curable ink. However, when such a design is applied, the problem of cracking or peeling off of the clear ink layer, especially in the thickly-encrusted portion, is conspicuous.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-described problems of the prior art, and to provide a method for producing a printed material that is resistant to cracking while ensuring hardness even when a thickly raised printed layer is subjected to heat treatment.

As a result of intensive studies to achieve the above object, the present inventors have found that printing and The present inventors have found that it is possible to form a clear layer that is resistant to cracking while ensuring hardness in the heat treatment after curing, and have completed the present invention.

That is, the method for producing a printed matter of the present invention is a method for producing a printed matter having a clear layer,
A first step of printing on a base material or a layer formed on a base material with an active energy ray-curable clear ink to form a clear layer, and then curing the clear layer. a first step in which the clear ink contains a polymerizable compound and a photopolymerization initiator, and the average number of functional groups of the polymerizable compound in the clear ink is 1.05 to 1.60;
and a second step of heating the printed material having the cured clear layer.

In a preferred embodiment of the printed matter manufacturing method of the present invention, the clear layer has a thickness of 10 to 400 μm and a difference between the minimum thickness and the maximum thickness of 30 μm or more.

In another preferred embodiment of the printed matter manufacturing method of the present invention, the layer formed on the substrate includes a colored layer.

In another preferred embodiment of the printed matter manufacturing method of the present invention, the layers formed on the substrate include a base coat layer or a primer layer and a colored layer.

In another preferred embodiment of the printed matter manufacturing method of the present invention, the heating temperature is in the range of 70 to 300° C. in the second step.

ADVANTAGE OF THE INVENTION According to this invention, even if the printing layer which piled up thickly is heat-processed, the manufacturing method of printed matter which is hard to crack can be provided, ensuring hardness.

Clear layer pattern A printed for crack resistance evaluation Clear layer pattern B printed for crack resistance evaluation Clear layer pattern C printed for crack resistance evaluation Clear layer printed for crack resistance evaluation (clear layer printed with patterns A, B, and C stacked in order)

The method for producing a printed matter according to the present invention will be described in detail below. The present invention is a method for producing a printed matter having a clear layer, comprising a step of forming a clear layer using an active energy ray-curable clear ink (first step: clear layer forming step), and heating a printed matter having a clear layer. (second step: heat treatment step).

In the method for producing a printed matter of the present invention, the clear layer forming step includes printing with an active energy ray-curable clear ink on a substrate or a layer formed on a substrate to form a clear layer, The next step is to harden the clear layer.

Here, when printing is performed on the base material in the clear layer forming step, the clear layer is formed on part or the entire surface of the base material. Moreover, when printing is performed on a layer formed on a base material, the clear layer is formed on part or the entire surface of the layer formed on the base material. When printing is performed on a layer formed on part of the base material surface, the clear layer may be formed on part or the whole of the base material surface that is not covered with the layer. The clear layer may be one layer or a plurality of layers of two or more layers. When the clear layer is a plurality of layers, it is possible to easily form a thick portion, and thereby, it is also possible to impart a texture and a three-dimensional effect in accordance with the design given to the base.

The ink used in the clear layer forming step is an active energy ray-curable clear ink containing a polymerizable compound and a photopolymerization initiator. In this specification, the ink used in the clear layer forming step is also referred to as clear layer ink.

In this specification, active energy ray-curable ink means an ink composition that can be cured by irradiation with active energy rays such as ultraviolet rays, visible rays, and electron beams.

In this specification, clear ink refers to a clear ink having a light transmittance of 80% or more in a wavelength range of 380 to 800 nm when a film having a thickness of 30 μm is formed, and the light transmittance is preferably 80% or more, more preferably 90% or more. In this specification, the light transmittance is measured according to JIS K7361-1:1997 "Plastics-Testing method for total light transmittance of transparent materials-Part 1: Single beam method".

The polymerizable compound exhibits a reactive functional group (e.g., an acryloyl group, a methacryloyl group, a vinyl group, or a polymerizable unsaturated group such as a carbon-carbon double bond that constitutes an allyl group) when irradiated with an active energy ray. A compound that undergoes a polymerization reaction. In addition, a polymerizable compound may be used individually by 1 type, and may be used in combination of 2 or more types. The amount of the polymerizable compound in the active energy ray-curable clear ink is preferably 70 to 97% by mass.

Polymerizable compounds are classified as monofunctional polymerizable compounds or multifunctional polymerizable compounds. Here, the monofunctional polymerizable compound includes a monofunctional polymerizable monomer having one functional group exhibiting reactivity when irradiated with an active energy ray (for example, a monofunctional polymerizable monomer having one polymerizable unsaturated group) or an active Examples thereof include monofunctional polymerizable oligomers having one functional group that exhibits reactivity when irradiated with energy rays (for example, monofunctional polymerizable oligomers having one polymerizable unsaturated group). Examples of the polyfunctional polymerizable compound include polyfunctional polymerizable monomers having two or more functional groups that exhibit reactivity when irradiated with active energy rays (for example, polyfunctional polymerizable monomers having two or more polymerizable unsaturated groups) and active Examples thereof include polyfunctional polymerizable oligomers having two or more functional groups that exhibit reactivity when irradiated with energy rays (for example, polyfunctional polymerizable oligomers having two or more polymerizable unsaturated groups).

Specific examples of monofunctional polymerizable monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6- Hydroxyhexyl (meth)acrylate, polyoxyethylene mono(meth)acrylate, polyoxypropylene mono(meth)acrylate, polyoxybutylene mono(meth)acrylate, stearyl (meth)acrylate, acryloylmorpholine, tridecyl (meth)acrylate, lauryl (Meth)acrylates, dimethylacrylamide, hydroxyethylacrylamide, diethylacrylamide, isopropylacrylamide, dimethylaminopropylacrylamide, diacetoneacrylamide, Nn-butoxymethylacrylamide, N-isobutoxymethylacrylamide, N-methoxymethylacrylamide, N- Methylolacrylamide, N-vinylcaprolactam, decyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, benzyl (meth)acrylate, isodecyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, octyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butyl Cyclohexyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl-diglycol (meth)acrylate, EO (ethylene oxide)-modified 2-ethylhexyl (meth)acrylate, neopentyl glycol (meth)acrylate benzoate, N- Vinyl-2-pyrrolidone, N-vinylimidazole, tetrahydrofurfuryl (meth)acrylate, methoxydipropylene glycol (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth) ) acrylate, cyclic trimethylolpropane formal (meth)acrylate, and ethoxy-diethylene glycol (meth)acrylate.

Among polyfunctional polymerizable monomers, specific examples of polyfunctional polymerizable monomers (bifunctional polymerizable monomers) having two functional groups exhibiting reactivity upon irradiation with active energy rays include 1,12-dodecanediol di(meth ) acrylate, 1,10-decanediol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate , 1,9-nonanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1 , 4-butanediol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, dimethylol Cyclohexane di(meth)acrylate, neopentylglycol hydroxypivalate di(meth)acrylate, neopentylglycol di(meth)acrylate, PO (propylene oxide)-modified neopentylglycol di(meth)acrylate, tetraethylene glycol di(meth) Acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate and the like.

Further, specific examples of the polyfunctional polymerizable monomer (trifunctional or higher polyfunctional polymerizable monomer) having three or more functional groups exhibiting reactivity upon irradiation with active energy rays include trimethylolpropane tri(meth)acrylate, ethoxy trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated glycerin tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, EO modified Examples include diglycerin tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and EO-modified dipentaerythritol hexa(meth)acrylate.

As used herein, the term (meth)acrylate means methacrylate or acrylate. In addition, when a prefix indicating a plurality of (meth)acrylates such as di(meth)acrylate, tri(meth)acrylate, etc. is attached to each (meth)acrylate, each (meth)acrylate moiety may be the same or different. good too.

The amount of the monofunctional polymerizable monomer in the active energy ray-curable clear ink is preferably 30 to 90% by mass. The amount of the polyfunctional polymerizable monomer in the active energy ray-curable clear ink is, for example, 1 to 50% by mass, preferably 5 to 40% by mass, and particularly preferably 5 to 30% by mass. If the amount of the polyfunctional polymerizable monomer is less than 1% by mass, the curability may be lowered, and if it exceeds 50% by mass, the volume shrinkage of the printed film during curing may cause the ink layer to crack easily when it is thick. Sometimes. In addition, it is preferable to combine the bifunctional polymerizable monomer which has an alicyclic structure among polyfunctional polymerizable monomers.

The active energy ray-curable clear ink preferably contains a polyfunctional polymerizable compound having an alicyclic structure as the polymerizable compound. By using a polyfunctional polymerizable compound having an alicyclic structure, it is possible to form a printed film that is hard to crack even when formed into a thick film. Regarding this point, the present inventors have found that polyfunctional polymerizable compounds having an alicyclic structure have properties of both a cyclic compound and an aliphatic compound, so that the volume shrinkage of the printed film during curing is suppressed, and the film It is speculated that it is possible to relax the internal stress of the film and provide a printed film that is hard to crack even when formed into a thick film. Curability can also be improved.

The polyfunctional polymerizable compound having an alicyclic structure is preferably a bifunctional polymerizable monomer having an alicyclic structure, and among them, tricyclodecanedimethanol di(meth)acrylate or cyclohexanedimethanol di(meth)acrylate is particularly preferable. .

In the active energy ray-curable clear ink, the amount of the polyfunctional polymerizable compound having an alicyclic structure is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and particularly preferably 10 to 30% by mass. be. Polyfunctional polymerizable compounds having an alicyclic structure may be used singly or in combination of two or more. If the amount of the polyfunctional polymerizable compound having an alicyclic structure is less than 1% by mass, the curability may decrease. Layers may crack easily.

The active energy ray-curable clear ink preferably contains a nitrogen-containing polymerizable compound as the polymerizable compound. Adhesion of the printed film can be improved by using the nitrogen-containing polymerizable compound. Furthermore, since it is thermosetting, a reaction can be caused by heat treatment, and the surface hardness can be increased. The nitrogen-containing polymerizable compound can cause yellowing of the printed film, but by using the (II) silicon-containing compound described later, the heat-resistant yellowing can be improved, so even when a thick film is formed, It can provide excellent transparency.

The nitrogen-containing polymerizable compound is preferably a nitrogen-containing polymerizable monomer. Moreover, the nitrogen-containing polymerizable compound has, for example, nitrogen-containing groups such as amino groups, amide groups, imide groups, urea groups, and urethane groups. The amount of the nitrogen-containing polymerizable compound in the active energy ray-curable clear ink is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, and particularly preferably 3 to 10% by mass. The nitrogen-containing polymerizable compounds may be used singly or in combination of two or more.

（式中、Ｒ^１は、水素原子又は炭素数が１～８のアルキル基であり、Ｒ^２は、水素原子又はメチル基である）で表される化合物を含むことが好ましい。構造式（Ｉ）で表される化合物は、付着性の向上効果が高い。さらに、熱硬化性であるため、加熱処理により反応を起こし、表面硬度を上げる効果が高い。 The nitrogen-containing polymerizable compound has the structural formula (I)

(wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ² is a hydrogen atom or a methyl group). The compound represented by Structural Formula (I) is highly effective in improving adhesion. Furthermore, since it is thermosetting, it is highly effective in raising the surface hardness by causing a reaction upon heat treatment.

In Structural Formula (I), R ¹ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Here, the alkyl group may be linear or branched, preferably an alkyl group having 1 to 4 carbon atoms. Specific examples include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group and the like. The alkyl group may be unsubstituted or substituted, but is preferably an unsubstituted alkyl group. A halogen etc. are mentioned as a substituent of an alkyl group. In Structural Formula (I), R ² is a hydrogen atom or a methyl group, preferably hydrogen.

Specific examples of the compound represented by Structural Formula (I) preferably include Nn-butoxymethylacrylamide, N-isobutoxymethylacrylamide, N-methoxymethylacrylamide and N-methylolacrylamide.

The amount of the compound represented by Structural Formula (I) in the active energy ray-curable clear ink is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, and particularly preferably 3 to 10% by mass. be. The compounds represented by Structural Formula (I) may be used singly or in combination of two or more.

The active energy ray-curable clear ink preferably contains phenoxyethyl acrylate as a polymerizable compound from the viewpoint of lowering its viscosity and improving ejection properties.

From the viewpoint of improving adhesion, the active energy ray-curable clear ink preferably contains a hydroxyl group-containing polymerizable monomer as a polymerizable compound, and more preferably contains a hydroxyl group-containing monofunctional polymerizable monomer. Specific examples of hydroxyl group-containing polymerizable monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6- Hydroxyhexyl (meth)acrylate, hydroxyethyl acrylamide and the like are suitable. The amount of the hydroxyl group-containing polymerizable monomer in the active energy ray-curable clear ink is preferably 1 to 15% by mass. The hydroxyl group-containing polymerizable monomers may be used singly or in combination of two or more.

The active energy ray-curable clear ink preferably contains a polymerizable oligomer as the polymerizable compound. The polymerizable oligomer has little volume shrinkage and can provide a printed film that is hard to crack when heated even when formed into a thick film. The polymerizable oligomers are preferably acrylate oligomers. The number of functional groups of the polymerizable oligomer is preferably 2 to 6, and the molecular weight of the polymerizable oligomer is preferably 500 to 30,000, more preferably 1,000 to 20,000. Here, the molecular weight of the polymerizable oligomer is the weight average molecular weight in terms of polystyrene.

Specific examples of acrylate oligomers include urethane acrylate oligomers [acrylate oligomers having multiple urethane bonds (-NHCOO-)], amino acrylate oligomers [acrylate oligomers having multiple amino groups (-NH ₂ )], epoxy acrylate oligomers [epoxy group ], silicone acrylate oligomer [acrylate oligomer having multiple siloxane bonds (-SiO-)], ester acrylate oligomer [acrylate oligomer having multiple ester bonds (-COO-)], and butadiene acrylate oligomer [butadiene units multiple acrylate oligomers] and the like. Among these, urethane acrylate oligomers are preferred.

Further, the following are known as acrylate oligomers.
beam set 502H, beam set 505A-6, beam set 550B, beam set 575, beam set AQ-17 (manufactured by Arakawa Chemical Industries),
AH-600, UA-306H, UA-306T, UA-306I, UA-510H, UF-8001G (manufactured by Kyoeisha Chemical Co., Ltd.),
ＣＮ９１０、ＣＮ９５９、ＣＮ９６３、ＣＮ９６４、ＣＮ９６５ＮＳ、ＣＮ９６６ＮＳ、ＣＮ９６９ＮＳ、ＣＮ９８０ＮＳ、ＣＮ９８１ＮＳ、ＣＮ９８２、ＣＮ９８３ＮＳ、ＣＮ９８５、ＣＮ９９１ＮＳ、ＣＮ９９６ＮＳ、ＣＮ２９２０、ＣＮ２９２１、ＣＮ８８８１ＮＳ、ＣＮ８８８３ＮＳ、ＣＮ９００１ＮＳ、ＣＮ９００４、ＣＮ９００５、ＣＮ９００９、ＣＮ９０１１、ＣＮ９０２１ＮＳ、ＣＮ９０２３、 ＣＮ９０２８、ＣＮ９０３０、ＣＮ９１７８ＮＳ、ＣＮ９２９０、ＣＮ９８９３ＮＳ、ＣＮ９２９、ＣＮ９８９ＮＳ、ＣＮ９６８ＮＳ、ＣＮ９００６ＮＳ、ＣＮ９０１０ＮＳ、ＣＮ９０２５、ＣＮ９０２６、ＣＮ９０３９、ＣＮ９０６２、ＣＮ９１１０ＮＳ、ＣＮ９０２９、ＣＮ８８８５ＮＳ、ＣＮ９０１３ＮＳ、ＣＮ９７３、ＣＮ９７８ＮＳ、ＣＮ９９２、ＣＮ９１６７、ＣＮ９７８２、ＣＮ９７８３、ＣＮ９７０、 CN971, CN972, CN975NS, CN9165 (manufactured by Sartomer),
U-2PPA, U-6LPA, U-10HA, U-10PA, UA-1100H, U-15HA, UA-53H, UA-33H, U-200PA, UA-200PA, UA-160TM, UA-290TM, UA- 4200, UA-4400, UA-122P (manufactured by Shin-Nakamura Chemical Co., Ltd.),
New Frontier R-1235, R-1220, RST-201, RST-402, R-1301, R-1304, R-1214, R-1302XT, GX-8801A, R-1603, R-1150D (Daiichi Kogyo Seiyaku Co., Ltd.) company),
ＥＢＥＣＲＹＬ２０４、ＥＢＥＣＲＹＬ２０５、ＥＢＥＣＲＹＬ２１０、ＥＢＥＣＲＹＬ２１５、ＥＢＥＣＲＹＬ２２０、ＥＢＥＣＲＹＬ２３０、ＥＢＥＣＲＹＬ２４４、ＥＢＥＣＲＹＬ２４５、ＥＢＥＣＲＹＬ２６４、ＥＢＥＣＲＹＬ２６５、ＥＢＥＣＲＹＬ２７０、ＥＢＥＣＲＹＬ２８０／１５ＩＢ、ＥＢＥＣＲＹＬ２８４、ＥＢＥＣＲＹＬ２８５、ＥＢＥＣＲＹＬ２９４／２５ＨＤ、ＥＢＥＣＲＹＬ１２５９、ＥＢＥＣＲＹＬ１２９０、ＫＲＭ８２００、ＥＢＥＣＲＹＬ４２６５、ＥＢＥＣＲＹＬ４８２０、ＥＢＥＣＲＹＬ４８５８、ＥＢＥＣＲＹＬ５１２９、ＥＢＥＣＲＹＬ８２１０、 ＥＢＥＣＲＹＬ８２５４、ＥＢＥＣＲＹＬ８３０１Ｒ、ＥＢＥＣＲＹＬ８３０７、ＥＢＥＣＲＹＬ８４０２、ＥＢＥＣＲＹＬ８４０５、ＥＢＥＣＲＹＬ８４１１、ＥＢＥＣＲＹＬ８４６５、ＥＢＥＣＲＹＬ８８００、ＥＢＥＣＲＹＬ８８０４、ＥＢＥＣＲＹＬ８８０７、ＥＢＥＣＲＹＬ９２６０、ＥＢＥＣＲＹＬ９２７０、ＥＢＥＣＲＹＬ７７３５、ＥＢＥＣＲＹＬ８２９６、ＥＢＥＣＲＹＬ８４５２、ＥＢＥＣＲＹＬ８９０４、ＥＢＥＣＲＹＬ８３１１、ＥＢＥＣＲＹＬ８７０１、ＥＢＥＣＲＹＬ８６６７（ダイセル・オルネクス社製）、
UV-1700B, UV-6300B, UV-7550B, UV-7600B, UV-7605B, UV-7610B, UV-7630B, UV-7640B, UV-7650B, UV-6630B, UV-7000B, UV-7510B, UV- 7461TE,
UV-2000B, UV-2750B, UV-3000B, UV-3200B, UV-3300B, UV-3310B, UV-3700B, UV6640B (manufactured by Nippon Synthetic Chemical Co., Ltd.),
Art resin UN-333, UN-350, UN-1255, UN-2600, UN-2700, UN-5590, UN-6060PTM, UN-6200, UN-6202, UN-6300, UN-6301, UN-7600, UN-7700, UN-9000PEP, UN-9200A, UN-3320HA, UN-3320HC, UN-904, UN-906S (manufactured by Negami Kogyo Co., Ltd.)

The amount of the polymerizable oligomer in the active energy ray-curable clear ink is preferably 1 to 20% by mass, more preferably 5 to 15% by mass. In addition, a polymerizable oligomer may be used individually by 1 type, and may be used in combination of 2 or more types. By containing 1% by mass or more of the polymerizable oligomer, formation of a thick film and cracking during heating can be effectively prevented, and the weather resistance of the ink film can be improved. It becomes easy to adjust the head suitable viscosity.

In the printed matter production method of the present invention, the average functional group number of the polymerizable compound in the active energy ray-curable clear ink is 1.05 to 1.60, preferably 1.10 to 1.50. More preferably 1.20 to 1.40. If the average number of functional groups of the polymerizable compound is within the range specified above, it is possible to prevent the clear layer from cracking that may occur during heat treatment even if the clear layer has a thick portion. On the other hand, if the average number of functional groups of the polymerizable compound is too high, the stress in the clear layer cannot be completely removed during the heat treatment, and the clear layer, especially the thickly-encrusted portion, tends to crack. On the other hand, if the average number of functional groups of the polymerizable compound is too low, the clear layer lacks hardness and is easily damaged, and contaminants and the like tend to adhere.

[Method for calculating the average number of functional groups]
As used herein, the term "functional group" in the "average number of functional groups" refers to a functional group that exhibits reactivity upon irradiation with active energy rays. The average number of functional groups represents the average number of functional groups per molecule of the polymerizable compound contained in the ink composition. It is the value divided by the total amount of the sexual compound.

The photopolymerization initiator has the effect of initiating the polymerization of the polymerizable compound described above when irradiated with active energy rays. The amount of the photopolymerization initiator in the ink is preferably 1 to 25% by mass, more preferably 3 to 20% by mass, even more preferably 3 to 15% by mass. When the content of the photopolymerization initiator is less than 1% by mass, the printed layer may be poorly cured. be. Furthermore, in order to accelerate the initiation reaction of the photopolymerization initiator, it is also possible to use an auxiliary agent such as a photosensitizer.

Examples of photopolymerization initiators include benzophenone-based compounds, acetophenone-based compounds, thioxanthone-based compounds, and phosphine oxide-based compounds. It is preferred that the wavelengths overlap as much as possible. In particular, the photopolymerization initiator preferably contains an acylphosphine oxide initiator from the viewpoint of improving resistance to yellowing during heating. Acylphosphine oxide-based initiators tend to yellow the printed film more easily than other initiators when cured by irradiation with active energy rays, but the subsequent heat treatment improves the transparency. In addition, a photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more types.

Specific examples of photopolymerization initiators include:
2,2-dimethoxy-1,2-diphenylethan-1-one,
1-hydroxy-cyclohexyl-phenyl-ketone,
2-hydroxy-2-methyl-1-phenylpropan-1-one,
benzophenone,
1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one,
2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methyl-propan-1-one,
phenylglyoxylic acid methyl ester,
2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one,
2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone,
2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one,
bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,
bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide,
2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide,
1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)],
Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime),
2,4-diethylthioxanthone,
2-isopropylthioxanthone,
2-chlorothioxanthone and the like.

Among these, from the viewpoint of ink curability, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl -phosphine oxide and 2,4-diethylthioxanthone are preferred, and from the viewpoint of improving yellowing resistance during heating, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2, 6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide are preferred, 2,4,6-trimethylbenzoyl-diphenyl-phosphine Oxides are particularly preferred.

（式中、ｘは０又は１であり、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立して水素原子、又はアルキル基であり、Ｒ^４は炭素数１～１０の有機基である）で表されるケイ素含有化合物を含むことが好ましい。構造式（ＩＩ）で表される化合物は、付着性の向上を目的として使用される物質であるが、驚くべきことに、構造式（ＩＩ）で表される化合物を用いることで、耐熱黄変性をも向上でき、厚膜を形成した際にも優れた透明性を提供することができる。この点について、本発明者は、インク組成物に構造式（ＩＩ）の化合物を配合すると、構造式（ＩＩ）の化合物は、インク中の重合性化合物と結合し、膜自体の結晶性が高まり、加熱処理後の透明度が向上したものと推察する。本明細書においては、構造式（ＩＩ）で表される化合物を（ＩＩ）ケイ素含有化合物とも称する。 The active energy ray-curable clear ink may contain a silicon-containing compound and has the following structural formula (II)

(Wherein, x is 0 or 1, R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group, and R ⁴ is an organic group having 1 to 10 carbon atoms) It preferably contains a silicon-containing compound that is The compound represented by the structural formula (II) is a substance used for the purpose of improving adhesion. can also be improved, and excellent transparency can be provided even when a thick film is formed. In this regard, the present inventor found that when the compound of structural formula (II) is added to the ink composition, the compound of structural formula (II) bonds with the polymerizable compound in the ink, and the crystallinity of the film itself increases. , it is inferred that the transparency after the heat treatment was improved. In this specification, the compound represented by Structural Formula (II) is also referred to as (II) silicon-containing compound.

In Structural Formula (II), R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group. Here, the alkyl group may be linear or branched, preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms. Specific examples include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group and the like. The alkyl group may be unsubstituted or substituted, but is preferably an unsubstituted alkyl group. In addition, a halogen etc. are mentioned as a substituent of an alkyl group.

In Structural Formula (II), R ⁴ is an organic group having 1 to 10 carbon atoms. Here, the organic group preferably has at least one functional group that exhibits reactivity with the polymerizable compound. It is more preferable to have one or more kinds of polymerizable unsaturated groups, and it is even more preferable to have one or more kinds of functional groups such as acryloyl groups and methacryloyl groups. As used herein, the term (meth)acryloyl group means an acryloyl group or a methacryloyl group. Here, the organic group includes, for example, methyl group, ethyl group, propyl group, isopropyl group, hexyl group, octyl group, decyl group, cyclohexyl group, phenyl group, vinyl group, allyl group, 2-(3,4- epoxycyclohexyl)ethyl group, 3-glycidoxypropyl group, p-styryl group, 3-methacryloxypropyl group, 3-acryloxypropyl group, N-2-(aminoethyl)-3-aminopropyl group, 3- aminopropyl group, N-(1,3-dimethyl-butylidene)propylamino group and the like.

In Structural Formula (II), x is 0 or 1.

(II) Specific examples of silicon-containing compounds include methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, n-propyltrimethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, and isopropyltrimethoxysilane. Silane, isopropyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, cyclohexyl methyldimethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane , 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-amino Propylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-amino propyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and the like. Among these, methyltrimethoxysilane, n-propyltrimethoxysilane, phenyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxysilane Propylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane are preferred.

The amount of the silicon-containing compound (II) in the active energy ray-curable clear ink is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, particularly preferably 1 to 5% by mass, and most preferably 0.5% to 10% by mass. It is preferably 2 to 5% by mass. (II) Silicon-containing compounds may be used singly or in combination of two or more.

The active energy ray-curable clear ink preferably contains either an ultraviolet absorber or a radical scavenger, or both an ultraviolet absorber and a radical scavenger.

The ultraviolet absorber has the action of absorbing ultraviolet rays and preventing deterioration due to ultraviolet rays. Examples of UV absorbers include cyanoacrylate compounds, benzophenone compounds, benzoate compounds, benzotriazole compounds, hydroxyphenyltriazine compounds, benzylidene camphor compounds, inorganic fine particles, etc. Among them, UV absorption is at a shorter wavelength. Hydroxyphenyltriazine-based compounds are preferred from the viewpoint of ink curability. From the viewpoint of curability, it is preferable that the wavelength of the irradiated active energy ray and the absorption wavelength of the ultraviolet absorber do not overlap as much as possible.

Specific examples of UV absorbers include:
2,4-dihydroxybenzophenone,
2-hydroxy-4-methoxybenzophenone,
2-hydroxy-4-methoxybenzophenone-5-sulfonic acid,
2-hydroxy-4-octoxybenzophenone,
2-hydroxy-4-dodecyloxybenzophenone-2-hydroxy-4-benzyloxybenzophenone,
bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane,
2,2′-dihydroxy-4-methoxybenzophenone,
2,2′-dihydroxy-4,4′-dimethoxybenzophenone,
2,2′,4,4′-tetrahydroxybenzophenone,
2-hydroxy-4-methoxy-2'-carboxybenzophenone,
2-(2'-hydroxy-5'-methylphenyl)benzotriazole 2-[2'-hydroxy-3',5'-bis(α,α-(dimethylbenzyl)phenyl]benzotriazole,
2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole,
2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole,
2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole,
2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzotriazole,
2-(2′-hydroxy-5′-t-octylphenyl)benzotriazole,
2,2′-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-(2N-benzotriazol-2-yl)phenol],
condensation products of methyl-3-[3-t-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate and polyethylene glycol;
2-(2-hydroxyphenyl)benzotriazole,
2-(2′-hydroxy-5′-methylphenyl)benzotriazole,
2,6-di-t-butylphenyl-3′,5′-di-t-butyl-4′-hydroxybenzoate,
hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate and the like.

In the active energy ray-curable clear ink, the amount of the ultraviolet absorber is preferably 0.1 to 15% by mass, more preferably 0.1 to 10% by mass, and still more preferably 0.2% from the viewpoint of weather resistance. It is preferably in the range of ~5% by mass. If the amount of ultraviolet absorber is too large, the printed layer may not be sufficiently cured. The UV absorbers may be used singly or in combination of two or more, but the UV absorbers preferably contain at least two UV absorbers. By using a plurality of types of ultraviolet absorbers having different structures, the effects of the ultraviolet absorbers can be maintained longer.

A radical scavenger can scavenge free radicals and the like to improve photostability. Radical scavengers also include substances that react with free radicals and have the function of preventing polymerization reactions (so-called polymerization inhibitors). Examples of radical scavengers include hindered amine compounds, hydroquinone compounds, phenol compounds, phenothiazine compounds, nitroso compounds, N-oxyl compounds, etc. Hindered amine light stabilizers (HALS) are particularly preferred.

Specific examples of radical scavengers include bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1-{2-(3-(3,5-di-t-butyl-4- hydroxyphenyl)propionyloxy)ethyl}-2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro {4. 5} Hindered amine compounds such as decane-2,4-dione, phenol, o-, m- or p-cresol, 2-t-butyl-4-methylphenol, 6-t-butyl-2,4-dimethylphenol , 2,6-di-t-butyl-4-methylphenol, 2-t-butylphenol, 4-t-butylphenol, 2,4-di-t-butylphenol, 2-methyl-4-t-butylphenol, 4- Phenolic compounds such as t-butyl-2,6-dimethylphenol, hydroquinone, hydroquinone monomethyl ether, methylhydroquinone, 2,5-di-t-butylhydroquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone , trimethylhydroquinone 4-methylbenzcatechin, t-butylhydroquinone, 3-methylbenzcatechin, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, trimethylhydroquinone, t-butylhydroquinone, benzoquinone, t-butyl-p -benzoquinone, hydroquinone compounds such as 2,5-diphenyl-p-benzoquinone, phenothiazine compounds such as phenothiazine, N-nitroso-N-phenylhydroxylamine ammonium, nitroso such as N-nitroso-N-phenylhydroxylamine aluminum salt compound, 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-methoxy-2 , 2,6,6-tetramethyl-piperidine-N-oxyl and other N-oxyl compounds.

In the active energy ray-curable clear ink, the amount of the radical scavenger is preferably 0.1 to 15% by mass, more preferably 0.1 to 10% by mass, and particularly preferably 0.2% from the viewpoint of weather resistance. It is preferably in the range of ~5% by mass. Too much radical scavenger may cause poor curing. A radical scavenger may be used individually by 1 type, and may be used in combination of 2 or more types.

As long as the active energy ray-curable clear ink is a clear ink, it may contain a coloring agent such as a dye or a pigment, but in that case, it preferably contains a pigment from the viewpoint of weather resistance. For example, it is possible to use metallic pigments or pearl pigments to obtain metallic inks. The content of the colorant is, for example, preferably 0.1 to 5% by mass, more preferably 0.1 to 1% by mass in the ink. Colorants may be used singly or in combination of two or more.

Specific examples of colorants include:
C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 14, 15, 16, 17, 24, 32, 34, 35, 36, 37, 41, 42, 43, 49, 53, 55, 60, 61, 62, 63, 65, 73, 74, 75, 77, 81, 83, 87, 93, 94, 95, 97, 98, 99, 100, 101, 104, 105, 106, 108, 109, 110, 111, 113, 114, 116, 117, 119, 120, 123, 124, 126, 127, 128, 129, 130, 133, 138, 139, 150, 151, 152, 153, 154, 155, 165, 167, 168, 169, 170, 172, 173, 174, 175, 176, 179, 180, 181, 182, 183, 184, 185, 191, 193, 194, 199, 205, 206, 209, 212, 213, 214, 215, 219,
C. I. Pigment Orange 1, 2, 3, 4, 5, 13, 15, 16, 17, 19, 20, 21, 24, 31, 34, 36, 38, 40, 43, 46, 48, 49, 51, 60, 61, 62, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 81,
C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 21, 22, 23, 31, 32, 38, 41, 48, 48:1, 48:2, 48:3, 48:4, 48:5, 49, 52, 52:1, 52:2, 53:1, 54, 57:1, 58, 60:1, 63, 64:1, 68, 81:1, 83, 88, 89, 95, 101, 104, 105, 108, 112, 114, 119, 122, 123, 136, 144, 146, 147, 149, 150, 164, 166, 168, 169, 170, 171, 172, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 187, 188, 190, 193, 194, 200, 202, 206, 207, 208, 209, 210, 211, 213, 214, 216, 220, 220, 221, 224, 226, 237, 238, 239, 242, 245, 247, 248, 251, 253, 254, 255, 256, 257, 258, 260, 262, 263, 264, 266, 268, 269, 270, 271, 272, 279,
C. I. Pigment Violet 1, 2, 3, 3:1, 3:3, 5:1, 13, 15, 16, 17, 19, 23, 25, 27, 29, 31, 32, 36, 37, 38, 42, 50,
C. I. Pigment Blue 1, 15, 15:1, 15:2, 15:3, 15:4, 15:5, 15:6, 16, 17:1, 24, 24:1, 25, 26, 27, 28, 29, 36, 56, 60, 61, 62, 63, 75, 79, 80,
C. I. Pigment Green 1, 4, 7, 8, 10, 15, 17, 26, 36, 50,
C. I. Pigment Brown 5, 6, 23, 24, 25, 32, 41, 42,
C. I. Pigment Black 1, 6, 7, 9, 10, 11, 20, 26, 28, 31, 32, 34,
C. I. Pigment White 1, 2, 4, 5, 6, 7, 11, 12, 18, 19, 21, 22, 23, 26, 27, 28,
Examples include aluminum flakes, glass flakes, pearl pigments and hollow particles.

Among these, from the viewpoint of weather resistance and color reproducibility of the printed layer,
C. I. Pigment Black 7,
C. I. Pigment Blue 15:3, C.I. I. Pigment Blue 15:4, C.I. I. Pigment Blue 28,
C. I. Pigment Red 101, C.I. I. Pigment Red 122, C.I. I. Pigment Red 202, C.I. I. Pigment Red 254, C.I. I. Pigment Red 282,
C. I. Pigment Violet 19,
C. I. Pigment White 6,
C. I. Pigment Yellow 42, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 138, C.I. I. Pigment Yellow 139, C.I. I. Pigment Yellow 150, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 213 is preferred.

From the viewpoint of ejection stability, the pigment particles dispersed in the ink preferably have a volume average particle diameter of 0.05 to 0.4 μm and a maximum volume particle diameter of 0.2 to 1 μm. When the volume average particle size is larger than 0.4 μm and the volume maximum particle size is larger than 1 μm, it tends to be difficult to stably eject the ink. The volume average particle size and the volume maximum particle size can be measured with a measuring instrument using a dynamic light scattering method.

The active energy ray-curable clear ink may further contain a pigment dispersant as necessary to disperse the pigment. The content of the pigment dispersant is, for example, 0.1 to 5% by mass in the ink. Moreover, a pigment dispersant may be used individually by 1 type, and may be used in combination of 2 or more types.

Specific examples of the pigment dispersant include:
ANTI-TERRA-U, ANTI-TERRA-U100,
ANTI-TERRA-204, ANTI-TERRA-205,
DISPERBYK-101, DISPERBYK-102,
DISPERBYK-103, DISPERBYK-106,
DISPERBYK-108, DISPERBYK-109,
DISPERBYK-110, DISPERBYK-111,
DISPERBYK-112, DISPERBYK-116,
DISPERBYK-130, DISPERBYK-140,
DISPERBYK-142, DISPERBYK-145,
DISPERBYK-161, DISPERBYK-162,
DISPERBYK-163, DISPERBYK-164,
DISPERBYK-166, DISPERBYK-167,
DISPERBYK-168, DISPERBYK-170,
DISPERBYK-171, DISPERBYK-174,
DISPERBYK-180, DISPERBYK-182,
DISPERBYK-183, DISPERBYK-184,
DISPERBYK-185, DISPERBYK-2000,
DISPERBYK-2001, DISPERBYK-2008,
DISPERBYK-2009, DISPERBYK-2020,
DISPERBYK-2025, DISPERBYK-2050,
DISPERBYK-2070, DISPERBYK-2096,
DISPERBYK-2150, DISPERBYK-2155,
DISPERBYK-2163, DISPERBYK-2164,
BYK-P104, BYK-P104S, BYK-P105,
BYK-9076, BYK-9077, BYK-220S, BYKJET-9150, BYKJET-9151 (manufactured by BYK-Chemie Japan),
Solsperse 3000, Solsperse 5000,
Solsperse 9000, Solsperse 11200,
Solsperse 13240, Solsperse 13650,
Solsperse 13940, Solsperse 16000,
Solsperse 17000, Solsperse 18000,
Solsperse 20000, Solsperse 21000,
Solsperse 24000SC, Solsperse 24000GR,
Solsperse 26000, Solsperse 27000,
Solsperse 28000, Solsperse 32000,
Solsperse 32500, Solsperse 32550,
Solsperse 32600, Solsperse 33000,
Solsperse 34750, Solsperse 35100,
Solsperse 35200, Solsperse 36000,
Solsperse 36600, Solsperse 37500,
Solsperse 38500, Solsperse 39000,
Solsperse 41000, Solsperse 54000,
Solsperse 55000, Solsperse 56000,
Solsperse 71000, Solsperse 76500,
Solsperse X300 (manufactured by Lubrizol),
Disparlon DA-7301, Disparlon DA-325, Disparlon DA-375, Disparlon DA-234 (manufactured by Kusumoto Kasei Co., Ltd.),
Floren AF-1000, Floren DOPA-15B, Floren DOPA-15BHFS, Floren DOPA-17HF, Floren DOPA-22, Floren DOPA-33, Floren G-600, Floren G-700, Floren G-700AMP, Floren G-700DMEA, Floren G-820, Floren G-900, Floren GW-1500, Floren KDG-2400, Floren NC-500, Floren WK-13E (manufactured by Kyoeisha Chemical Co., Ltd.),
TEGO Dispers610, TEGO Dispers610S,
TEGO Dispers 630, TEGO Dispers 650,
TEGO Dispers 652, TEGO Dispers 655,
TEGO Dispers662C, TEGO Dispers670,
TEGO Dispers 685, TEGO Dispers 700,
TEGO Dispers710, TEGO Dispers740W,
LIPOTIN A, LIPOTIN BL,
LIPOTIN DB, LIPOTIN SB (manufactured by Evonik Degussa),
PB821, PB822, PN411, PA111 (manufactured by Ajinomoto Fine-Techno Co., Inc.),
Texahall 963, Texahall 964, Texahall 987, Texahall P60, Texahall P61, Texahall P63, Texahall 3250, Texahall SF71, Texahall UV20, Texahall UV21 (manufactured by Cognis),
BorchiGenSN88, BorchiGen0451 (above, manufactured by Bosius) and the like.

The active energy ray-curable clear ink may further contain a surface modifier from the viewpoint of improving wettability. As used herein, a surface modifier means a substance that has a hydrophilic site and a hydrophobic site in its molecular structure and that can adjust the surface tension of ink when added.

Specific examples of surface modifiers that can be used for active energy ray-curable clear inks include anionic surface modifiers such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, and fatty acid salts, polyoxyethylene alkyl ethers, polyoxy Nonionic surface control agents such as ethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene/polyoxypropylene block copolymers; cationic surface control agents such as alkylamine salts and quaternary ammonium salts; acrylic surface control agents , silicon-based surface conditioners, and fluorine-based surface conditioners. In particular, silicon-based surface conditioners and acrylic-based surface conditioners are preferred, and commercially available products such as BYK-Chemie, Evonik, and Dow Corning Toray can be used. Furthermore, in the case of a silicone-based surface conditioner, it is preferably a polyether-modified silicone oil and has an HLB of 7.6 to 12.

The amount of the surface control agent in the active energy ray-curable clear ink can be appropriately selected depending on the purpose of use, but is preferably 0.01 to 1% by mass in the ink, for example. The surface conditioners may be used singly or in combination of two or more.

Specific examples of the surface conditioner include:
BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-313, BYK-315N, BYK-320, BYK-322, BYK-323, BYK-325, BYK-326, BYK- 330, BYK-331, BYK-333, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-350, BYK-354, BYK-355, BYK-356, BYK-358N, BYK-361N, BYK-370, BYK-375, BYK-377, BYK-378, BYK-381, BYK-392, BYK-394, BYK-399, BYK-3440, BYK-3441, BYK- 3455, BYK-3550, BYK-3560, BYK-3565, BYK-3760, BYK-DYNWET 800N, BYK-SILCLEAN 3700, BYK-SILCLEAN 3701, BYK-SILCLEAN 3720, BYK-UV3500, BYK-UV3503, BYK-UV10YK- BYK-UV3530, BYK-UV3535, BYK-UV3570, BYK-UV3575, BYK-UV3576 (manufactured by BYK-Chemie Japan),
ＴＥＧＯ Ｆｌｏｗ ３００、ＴＥＧＯ Ｆｌｏｗ ３７０、ＴＥＧＯ Ｆｌｏｗ ４２５、ＴＥＧＯ Ｆｌｏｗ ＡＴＦ ２、ＴＥＧＯ Ｆｌｏｗ ＺＦＳ ４６０、ＴＥＧＯ Ｇｌｉｄｅ １００、ＴＥＧＯ Ｇｌｉｄｅ １１０、ＴＥＧＯ Ｇｌｉｄｅ １３０、ＴＥＧＯ Ｇｌｉｄｅ ４０６、ＴＥＧＯ Ｇｌｉｄｅ ４１０、ＴＥＧＯ Ｇｌｉｄｅ ４１１、ＴＥＧＯ Ｇｌｉｄｅ ４１５、 TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 482, TEGO Glide A 115, TEGO Glide B 1484, TEGO Glide ZG 400 (manufactured by Evonik Japan),
501W ADDITIVE, FZ-2104, FZ-2110, FZ-2123, FZ-2164, FZ-2191, FZ-2203, FZ-2215, FZ-2222, FZ-5609, L-7001, L-7002, L-7604 , OFX-0193, OFX-0309 FLUID, OFX-5211 FLUID, SF 8410 FLUID, SH3771, SH 3746 FLUID, SH 8400 FLUID, SH 8700 FLUID, Y-7006 (manufactured by Dow Corning Toray Co., Ltd.),
KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-640, KF-642, KF-643, KF-644, KF-945, KF-6004, KF- 6011, KF-6012, KF-6015, KF-6017, KF-6020, KF-6204, X-22-2516, X-22-4515 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

Among these, in terms of structure and HLB, 501W ADDITIVE, FZ-2104, FZ-2123, FZ-2215, L-7002, OFX-0309 FLUID, OFX-5211 FLUID, SH 8400 FLUID, KF-351A, KF- 353, KF-355A, KF-615A, KF-642, KF-644, KF-6004, KF-6011, KF-6204 are preferred.

Other components of the active energy ray-curable clear ink include antioxidants, plasticizers, rust inhibitors, solvents, non-reactive polymers, fillers, antifoaming agents, charge control agents, stress relaxation agents, penetrants, Additives such as a light guide material, glitter material, magnetic material, and phosphor may be used as necessary.

The active energy ray-curable clear ink is mixed with various components appropriately selected as necessary, and if necessary, using a filter having a pore size of about 1/10 or less of the nozzle diameter of the inkjet print head to be used, It can be prepared by filtering the resulting mixture.

The active energy ray-curable clear ink preferably has a viscosity at 40° C. of 5 to 25 mPa·s, more preferably 5 to 20 mPa·s. If the ink viscosity at 40° C. is within the specified range, good ejection stability can be obtained. Ink viscosity can be measured using a cone-plate viscometer.

The active energy ray-curable clear ink preferably has a surface tension of 20 to 35 mN/m at 25° C., more preferably 23 to 33 mN/m. If the surface tension of the ink at 25° C. is within the specified range, good ejection stability can be obtained. Incidentally, the ink surface tension can be measured by a plate method.

In the clear layer forming step, printing is preferably performed by an inkjet printing method, but is not limited to this, and various methods such as gravure printing, offset printing, flexographic printing, screen printing, and coater methods are used. It is also possible to carry out by a printing method.

In this specification, printing means applying ink onto an object by means of printing, and is not limited to those for the purpose of coloring the object, or drawing characters, images, etc., on the surface of the object. It is also included for the purpose of coating the object, or for the purpose of performing surface treatment on the object. In this specification, the ink for use in the inkjet printing method is also referred to as inkjet ink.

Various inkjet printers can be used for inkjet printing. Examples of inkjet printers include inkjet printers that eject an ink composition by a charge control method or a piezo method. In addition, a large-sized inkjet printer, as a specific example, an inkjet printer for the purpose of printing on articles produced on an industrial line can also be suitably used.

In the clear layer forming step, curing of the clear layer is preferably performed by irradiation with light having a peak wavelength in the range of 350 nm or more and 400 nm or less. Here, a high-pressure mercury lamp, a metal halide lamp, an LED lamp, or the like can be used as the light source. Moreover, it is preferable that the wavelength of the active energy ray irradiated to cure the ink layer overlaps with the absorption wavelength of the photopolymerization initiator. Although it is not particularly limited, for example, the integrated amount of active energy rays is preferably in the range of 100 to 5,000 mJ/cm ² .

In the clear layer forming step, the active energy ray-curable clear ink can be subjected to surface finishing such as gloss tone and matte tone by appropriately selecting ejection conditions for inkjet printing and subsequent curing conditions. For example, if the ink is ejected and cured after a period of time (after the ink has wetted and spread), the surface of the printed matter can be finished in a glossy finish. The surface of the printed matter can be finished in a matt tone by curing while the dots remain independent without wetting and spreading. Furthermore, by adjusting the printed image, changing the ink distribution, changing the ink head, changing the amount of ink droplets ejected, and changing the number of printing passes, the gloss difference can be changed. can also In addition, by forming a thick portion on the clear layer, it is possible to add a texture and a three-dimensional effect according to the design applied to the base. There is a method in which an image is drawn with color ink, and unevenness is formed thereon with clear ink to give texture and a three-dimensional effect, and there is a method in which unevenness is formed with clear ink and then an image is drawn with color ink. Combining and stacking color ink layers and clear ink layers, it is possible to express complex shades. When forming a thick film portion with clear ink, by stacking the same image, a building-shaped convex portion can be formed. By gradually reducing the area of the image and stacking the images, a sharp mountain-shaped convex portion can be formed. On the other hand, by gradually increasing the area of the image and laminating the images, it is possible to form a gentle mountain-shaped convex portion. When forming a thick portion with a clear layer, in order to increase the printing efficiency, there is a method of increasing the discharge amount of the clear ink by changing the ink head. Furthermore, it is also possible to perform lenticular printing. For example, by ejecting clear ink onto a colored layer consisting of two or more colors to form a dome-shaped clear layer, it is possible to provide a printed material whose image changes depending on the viewing angle. In addition, by combining a clear ink layer or a color ink layer and a clear ink layer, wood grain, stone grain, brick, leather, sand, concrete, fur, carbon, cloth, A wide variety of designs such as tile tone, glass tone, metal tone, ceramic tone, pearl tone, paper tone, Japanese paper tone, hairline tone, and etching tone can be expressed.

The base material is not particularly limited as long as it has heat resistance that can withstand the heating of the printed matter described later. Examples of such materials include metals such as iron, stainless steel, aluminum, copper, titanium and alloys thereof, cement, concrete, gypsum, calcium silicate, calcium carbonate, marble, artificial marble, glass, and ceramics. or a combination of two or more of these materials. In addition, the surface of the base material may be subjected to pretreatment such as degreasing treatment, chemical conversion treatment, polishing, or the like, sealer, primer coating, or the like. The substrate surface may be smooth, uneven, or three-dimensional. In the present invention, by using a base material having such materials and properties, it can be suitably used for applications such as furniture, building materials, and small metal articles.

The base material may have a layer (for example, a coating film or a printed film) formed on part or all of its surface, and various designs can be applied thereto. For example, a coating film formed of paint, a printed film formed of ink, a printed film formed of powder toner, or the like may be formed on the substrate. The layer formed on the base material includes resins, colorants such as dyes and pigments, ultraviolet absorbers, radical scavengers, antioxidants, plasticizers, rust inhibitors, fillers, charge control agents, light guide materials, Luminescent materials, magnetic materials, phosphors, waxes, and the like can be included.

Paints and inks used to form a layer on a substrate include organic solvent-based paints and inks using an organic solvent as the main solvent, water-based paints and inks using water as the main solvent, and active agents using a polymerizable compound. Examples include various paints and inks such as energy ray-curable paints and inks, and powder paints. Here, the components that can be used in the active energy ray-curable ink include the components that can be used in the clear layer ink described above.

In the clear layer forming step, means for forming a layer on the substrate are not particularly limited. For example, in the case of paint, various coating means such as air spray, airless spray, roll coater, flow coater and electrostatic coating can be used. In the case of ink, various printing means such as gravure printing, offset printing, flexographic printing, screen printing, coater printing, and inkjet printing can be used. In the case of a powder toner, an electrophotographic printing means (specifically, an image forming apparatus such as a copying machine or a laser printer) can be used.

In the clear layer forming step, the layer formed on the substrate before printing for forming the clear layer may be a single layer or a plurality of layers, and in the case of a plurality of layers, it is composed of different layers. good too. The configuration of the layer formed on the substrate includes a configuration including a colored layer on the substrate, a configuration including a base coat layer or a primer layer on the substrate, a configuration including a primer layer and a base coat layer in this order, and a configuration including a base coat layer on the substrate. Examples include a configuration in which a base coat layer or a primer layer and a colored layer are provided in order on the substrate, and a configuration in which a primer layer, a base coat layer, and a colored layer are provided in order on a substrate. In this specification, the colored layer is mainly a layer for coloring the substrate or drawing characters, images, etc., and the base coat layer or primer layer is mainly a colored layer or a clear layer. It is a layer intended to cover the surface of the substrate from the viewpoint of improving the adhesion of the coloring layer, the coloring property of the coloring layer, etc., and the role of the coloring layer. As the base coat layer or primer layer, known ones can be applied, for example, the coating layer described in JP-A-2019-77090 and JP-A-2019-162732, JP-A-2018-83343. A base layer and the like are included.

In the printed matter manufacturing method of the present invention, the heat treatment step is a step of heating the printed matter having the clear layer obtained in the clear layer forming step. This makes it possible to solve the problem of odor and stickiness of the clear layer and the like, and also improve the adhesion of the clear layer and the like. Here, the heat treatment is performed, for example, within the range of 70°C to 300°C, preferably within the range of 70°C to 200°C from the viewpoint of yellowing resistance, and within the range of 70°C to 180°C. More preferably, it is performed in

The printed matter obtained by the method for producing a printed matter of the present invention comprises a clear layer on a base material, and may further comprise other layers such as a base coat layer, a primer layer and a colored layer.

In the printed matter obtained by the printed matter production method of the present invention, the clear layer preferably has a thickness in the range of 10 to 400 μm, and the difference between the minimum thickness and the maximum thickness in the clear layer is preferably 30 μm or more. preferable.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

<Ink preparation method>
A mixture according to the formulation shown in Tables 1 to 3 was obtained to prepare an active energy ray-curable inkjet ink.

Details of the ingredients shown in the formulation are given below.
1) Light acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd., phenoxyethyl acrylate 2) Light acrylate IB-XA, manufactured by Kyoeisha Chemical Co., Ltd., isobornyl acrylate 3) Light acrylate EC-A, manufactured by Kyoeisha Chemical Co., Ltd., ethoxy-diethylene glycol acrylate 4) Light acrylate DPM-A, manufactured by Kyoeisha Chemical Co., Ltd., methoxydipropylene glycol acrylate 5) Light acrylate THF-A, manufactured by Kyoeisha Chemical Co., Ltd., tetrahydrofurfuryl acrylate 6) Light ester HOA (N), manufactured by Kyoeisha Chemical Co., 2-hydroxyethyl acrylate 7) 4-HBA, manufactured by Osaka Organic Chemical Industry Co., Ltd., 4-hydroxyethyl acrylate 8) Praxel FA2D, manufactured by Daicel Chemical Industries, an adduct of 2-hydroxyethyl acrylate and ε-caprolactone 9) NBMA , MCC Unitec Co., Ltd., Nn-butoxymethyl acrylamide 10) Light acrylate 1.6HX-A, Kyoeisha Chemical Co., Ltd., 1,6-hexanediol diacrylate 11) Light acrylate 1.9ND-A, Kyoeisha Chemical Co., Ltd. , 1,9-nonanediol diacrylate 12) Light acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd., tricyclodecanedimethanol diacrylate 13) Light acrylate TMP-A, manufactured by Kyoeisha Chemical Co., Ltd., trimethylolpropane triacrylate 14) EBECRYL230 , manufactured by Daicel Allnex Co., Ltd., urethane acrylate oligomer, molecular weight 5,000
15) EBECRYL4265, manufactured by Daicel Ornex, urethane acrylate oligomer, molecular weight 650
16) EBECRYL1290, manufactured by Daicel Ornex, urethane acrylate oligomer, molecular weight 1,000
17) KBM-502, manufactured by Shin-Etsu Chemical Co., Ltd., 3-methacryloxypropylmethyldimethoxysilane 18) SPEEDCURE TPO, manufactured by Lambson, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide 19) Omnirad 651, manufactured by BASF , 2,2-dimethoxy-2-phenylacetophenone

<Printing process>
The ink prepared according to the formulations shown in Tables 1 to 3 is set in an inkjet printer, and the surface of a 0.8 mm × 100 mm × 50 mm aluminum substrate is painted with acrylic resin white paint manufactured by Dainippon Toryo Co., Ltd. A base layer is prepared, and an image (printing layer) of 100 mm×50 mm is prepared on the base layer.

<Pencil hardness>
An aluminum plate was coated with an acrylic resin white paint manufactured by Dainippon Toryo Co., Ltd. as described in <Printing process> above to prepare a base layer. Next, a solid image (thickness: 100 μm) is printed on the underlayer by an inkjet printer using an active energy ray-curable inkjet ink, and then an active energy ray with a main wavelength of 360 to 425 nm is applied at 2000 mJ using a metal halide lamp. /cm ² to cure the image (clear layer). Next, the surface temperature of the base material was raised to 180° C., and heating was performed for 20 minutes at this temperature to produce a printed matter. Next, the clear layer of the print was evaluated for pencil hardness by scratch hardness (pencil method) according to JIS K-5600-5-4. The results are shown in Tables 1-3.

<Crack resistance>
An aluminum plate was coated with an acrylic resin white paint manufactured by Dainippon Toryo Co., Ltd. as described in <Printing process> above to prepare a base layer. Next, an inkjet printer using an active energy ray-curable inkjet ink is used to print a solid image on the underlayer step by step, and then an active energy ray having a main wavelength of 360 to 425 nm is applied at 2000 mJ/cm ² using a metal halide lamp. The image (clear layer) was cured by irradiation. Next, the surface temperature of the base material was raised to 180° C., and heating was performed for 20 minutes at this temperature to produce a printed matter.
Specifically, the clear layer printed step by step is prepared by preparing three patterns shown in FIGS. is. The results are shown in Tables 1-3.
⊚: No cracks were observed in the pattern C region of the printed matter when the clear layer was prepared with a pattern A film thickness of 100 µm, a pattern B film thickness of 150 µm, and a pattern C film thickness of 150 µm. The maximum thickness of the clear layer is 400 μm, and the difference between the minimum thickness (100 μm) and the maximum thickness (400 μm) is 300 μm.
◯: No cracks were observed in the pattern C region of the printed matter when the clear layer was prepared with the pattern A having a film thickness of 80 μm, the pattern B having a film thickness of 100 μm, and the pattern C having a film thickness of 120 μm. The maximum thickness of the clear layer is 300 μm, and the difference between the minimum thickness (80 μm) and the maximum thickness (300 μm) is 220 μm.
Δ: When a clear layer was prepared with a pattern A film thickness of 50 μm, a pattern B film thickness of 100 μm, and a pattern C film thickness of 100 μm, cracks were not observed in the pattern C region of the printed matter. The maximum thickness of the clear layer is 250 μm, and the difference between the minimum thickness (50 μm) and the maximum thickness (250 μm) is 200 μm.
x: Cracks are observed in the pattern C area of the printed matter when the clear layer is prepared with a pattern A film thickness of 50 μm, a pattern B film thickness of 100 μm, and a pattern C film thickness of 100 μm. The maximum thickness of the clear layer is 250 μm, and the difference between the minimum thickness (50 μm) and the maximum thickness (250 μm) of the outermost layer is 200 μm.

<Heat-resistant yellowing>
A mixture according to the formulation of Example 1 in Table 1 was obtained to prepare an active energy ray-curable inkjet ink. Printing, curing, and heating were carried out in the same manner as described in <Pencil Hardness> above, except that the baking temperature was changed, to produce a printed matter. Next, the color of the clear layer of the printed matter was measured using a spectrophotometer (SpectroEye, manufactured by X-Rite). In the L*a*b* color system, the b value is an index of yellowness. The b values of the printed area and the non-printed area were measured, the difference between these b values was determined, and the thermal yellowing resistance was evaluated according to the following evaluation criteria. Table 4 shows the results.
A: Less than 2.0.
○: 2.0 or more and less than 3.0.
Δ: 3.0 or more and less than 4.0.
×: 4.0 or more.

<Adhesion>
Printing, curing and heating were carried out in the same manner as described in <Heat yellowing> above to prepare a printed matter. In addition, a printed material was similarly prepared by coating an acrylic plate with an acrylic urethane-based resin white paint manufactured by Dainippon Toryo Co., Ltd. Regarding the baking temperature, from the viewpoint of the heat resistance temperature of acrylic, 100° C. or higher is not carried out. A cross cut of 100 squares with a width of 1 mm was made on the clear layer of the printed matter, and a cellophane tape was sufficiently adhered and then peeled off. Adhesiveness was evaluated according to the following evaluation criteria. Table 4 shows the results.
A: Peeling is not observed at the cut portion.
◯: Less than 5% peeling was observed at the cut portion.
Δ: Peeling of 5% or more and less than 20% was confirmed at the cut portion.
x: Peeling of 20% or more was confirmed at the cut portion.

Claims (5)

A method for producing a printed matter having a clear layer,
A first step of printing on a base material or a layer formed on a base material with an active energy ray-curable clear ink to form a clear layer, and then curing the clear layer. a first step in which the clear ink contains a polymerizable compound and a photopolymerization initiator, and the average number of functional groups of the polymerizable compound in the clear ink is 1.05 to 1.60;
and a second step of heating the printed matter having the cured clear layer. 2. The method of producing a printed matter according to claim 1, wherein the clear layer has a thickness of 10 to 400 μm, and a difference between a minimum thickness and a maximum thickness of 30 μm or more. 3. The method for producing a printed matter according to claim 1, wherein the layer formed on the substrate includes a colored layer. 4. The method for producing a printed matter according to any one of claims 1 to 3, wherein the layers formed on the substrate include a base coat layer or a primer layer and a colored layer. 5. The method for manufacturing a printed matter according to claim 1, wherein the heating temperature in said second step is within a range of 70 to 300.degree.

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