JP2014148673A - Active energy ray-curable ink composition and printed body using the ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition which is excellent in followability even to a flexible substrate to be printed.SOLUTION: There is provided an active energy ray-curable ink composition which comprises active-energy-ray-polymerizable monomers and an active energy ray polymerization initiator, and comprises, as the active-energy-ray-polymerizable monomers, a monomer (A): a monofunctional monomer having a glass transition point of -30°C or less and a monomer (B): a multifunctional monomer having a glass transition point of 0°C or less. The monomer (B) is preferably a bifunctional monomer having a glass transition point of -30°C or less. In addition, as the active-energy-ray-polymerizable monomer, the active energy ray-curable ink composition further preferably contains a monomer (C): a monofunctional monomer having an alicyclic structure having a glass transition point of 0 to 110°C. Further, the ink composition may further contain a coloring material.

Description

  The present invention relates to an active energy ray-curable ink composition and a printed material obtained by printing the ink composition on a substrate having high flexibility at room temperature by an inkjet method.

  2. Description of the Related Art Conventionally, active energy ray-curable ink compositions that are cured by ultraviolet rays, electron beams, or other active energy rays have been developed. Since the active energy ray-curable ink composition is quick-drying, it can prevent bleeding of the ink even when printing on a substrate to be printed that does not absorb or hardly absorbs ink, such as plastic, glass, and coated paper. . The active energy ray-curable ink composition is composed of a polymerizable monomer, a polymerization initiator, a pigment and other additives.

  In recent years, printing is required not only when the substrate to be printed is plastic, glass, coated paper, etc., but also when it has flexibility such as polyethylene terephthalate resin, vinyl chloride resin, rubber, and the like. In this case, it is required to have a degree of elongation of 100% or more without causing cracks or peeling even if the printed body is stretched and to have durability in the degree of elongation.

  Examples of such an active energy ray-curable ink composition include (A) an acrylate monomer having a glass transition point of 0 ° C. or less of a homopolymer of 20% by mass to 65% by mass in the reaction component, and (B) a fat The thing containing the monofunctional acrylate which has a cyclic structure, and the polyfunctional acrylate which has (C) alicyclic structure is proposed (refer patent document 1). A printed matter obtained by printing this ink composition on a polyethylene terephthalate resin and a vinyl chloride resin has excellent flexibility, elongation durability, abrasion resistance, and weather resistance, and is stretched and attached to an article having a curved surface such as a vehicle body. Even so, cracks and peeling do not occur because of the durability in the degree of elongation.

  And (A) one or more monofunctional monomers selected from vinyl caprolactam, benzyl (meth) acrylate and isobornyl (meth) acrylate, and (B) di (meth) acrylate of a modified bisphenol A alkylene oxide. And one or more monomers selected from (C) 2-hydroxy-3-phenoxypropyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, and phenoxyethyl (meth) acrylate, (D) The thing containing an active energy ray polymerization initiator is proposed (refer patent document 2). According to this ink composition, even when printing on a thermoplastic resin sheet such as an acrylic resin or a polycarbonate resin, printing can be performed directly without providing a treatment layer, and the cured sheet can be used for thermoforming. I can do it. When the curved surface portion is formed by thermoforming, the sheet is partially stretched, but the ink composition is excellent in flexibility and adhesion, and therefore excellent in that no cracking or whitening occurs.

JP 2011-162703 A International Publication No. 2011/064977

  However, when printing on an elastomer base material, which is a high-molecular substance having rubber elasticity at room temperature, the base material to be printed is more flexible than the above base material and has a high degree of elongation. Higher followability with respect to the elongation of the resin is required, and since it has rubber elasticity at room temperature, it is required that peeling and cracking do not occur even if it is repeatedly expanded and contracted. The followability means that the substrate expands and contracts in synchronism without causing a crack with respect to the deformation of the base material (hereinafter the same).

  The present invention has been made in view of the above circumstances, and the object thereof is excellent in followability even on a substrate to be printed having high flexibility at room temperature such as an elastomer substrate. It is to provide an ink composition.

  In order to solve the above-mentioned problems, the present inventor has conducted extensive research and found that an active energy ray-curable ink composition containing an active energy ray polymerizable monomer and an active energy ray polymerization initiator has an active energy ray polymerization. The inventors have found that the above-mentioned problems can be solved by studying the composition of the functional monomer, and have completed the present invention. Specifically, the present invention provides the following.

  (1) The present invention contains an active energy ray polymerizable monomer and an active energy ray polymerization initiator, and as the active energy ray polymerizable monomer, monomer A): monofunctional having a glass transition point of −30 ° C. or lower. An active energy ray-curable ink composition containing a monomer and a monomer B): a polyfunctional monomer having a glass transition point of 0 ° C. or less.

  (2) Moreover, this invention is an active energy ray hardening-type ink composition as described in (1) whose said monomer B) is a bifunctional monomer whose glass transition point is -30 degrees C or less.

  (3) Moreover, this invention contains 2-65 mass% of said monomers A) among said active energy ray polymerizable monomers, and 2-30 mass% of said monomers B), (1) or (2) The active energy ray-curable ink composition described in 1.

  (4) Moreover, this invention further contains the monofunctional monomer which has an alicyclic structure whose glass transition point is 0 degreeC or more and 110 degrees C or less as said active energy ray polymerizable monomer, (1) To the active energy ray-curable ink composition according to any one of (3) to (3).

  (5) Moreover, this invention is an active energy ray hardening-type ink composition as described in (4) which contains the said monomer C) 20-65 mass% among the said active energy ray polymerizable monomers.

  (6) In the present invention, the monomer A) is any one or more monomers selected from isooctyl acrylate, tridecyl acrylate, and ethoxydiethylene glycol acrylate, and the monomer B) is polypropylene glycol diacrylate, polyethylene glycol. Any one or more monomers selected from diacrylate and EO-modified bisphenol A diacrylate, wherein the monomer C) is from isobornyl acrylate, 4-t-butylcyclohexyl acrylate, cyclohexyl acrylate and dicyclopentenyloxyethyl acrylate The active energy ray-curable ink composition according to (4) or (5), which is any one or more selected monomers.

  (7) Moreover, this invention is an active energy ray hardening-type ink composition in any one of (1) to (6) which contains a coloring material further.

  (8) In the present invention, the active energy ray-curable ink composition according to any one of (1) to (7) is a 1 mm-thick styrene butadiene rubber (hereinafter also referred to as “SBR”) sheet. A cured film-forming substrate formed on the cured film having a thickness of 10 μm is formed as a dumbbell-shaped No. 6 type (JIS K6251-5) test piece at 25 ° C. according to JIS K7161. 8. The active energy ray-curable ink composition according to claim 1, wherein, when a tensile test is performed at a tensile rate of 100 mm / min, elongation at break of a cured film at which cracking of the cured film occurs is 200% or more. It is.

  (9) Further, in the present invention, the active energy ray-curable ink composition is formed as a cured film having a thickness of 10 μm on an SBR sheet having a thickness of 1 mm, and the cured film-forming substrate on which the cured film is formed. When the expansion / contraction of the cured film-forming substrate is repeated 50 times at a strain rate of 100 mm / min so that the elongation is repeated in the range from 100% to 200%, the cured film does not crack, (1) To the active energy ray-curable ink composition according to any one of (8) to (8).

  (10) Further, the present invention is described in any one of (1) to (9), wherein the present invention is used as an ink for ink jet to an elastomer substrate or a substrate to be printed having a Young's modulus of 0.001 MPa to 30 MPa. This is an active energy ray-curable ink composition.

  (11) Moreover, this invention is an active energy ray hardening type | mold in any one of (1) to (10) on an elastomer base material or a to-be-printed base material whose Young's modulus is 0.001 MPa or more and 30 MPa or less. It is a printed body on which an ink cured film layer that is a cured film of the ink composition is formed.

  (12) Moreover, this invention is a printed body as described in (11) in which the surface protection layer which protects the surface of the said ink cured film layer is formed in the surface of the said ink cured film layer.

  (13) Moreover, the present invention provides the printing according to (11) or (12), wherein a primer layer is formed between the surface of the elastomer substrate or the substrate to be printed and the ink cured film layer. Is the body.

  (14) Further, in the present invention, the active energy ray-curable ink composition according to any one of (1) to (9) is printed on an elastomer substrate or has a Young's modulus of 0.001 MPa to 30 MPa. This is a method for producing a printed material, which is printed on a substrate by an inkjet method and then cured with ultraviolet rays.

  ADVANTAGE OF THE INVENTION According to this invention, the ink composition excellent in followable | trackability can be provided also on the to-be-printed base material (it may be called a flexible base material) which has high softness | flexibility at normal temperature like an elastomer base material.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. can do.

<Active energy ray-curable ink composition>
The active energy ray-curable ink composition of the present invention contains an active energy ray polymerizable monomer and an active energy ray polymerization initiator. The active energy ray polymerizable monomer is composed of monomer A): a monofunctional monomer having a glass transition point of −30 ° C. or less, and monomer B): a polyfunctional monomer having a glass transition point of 0 ° C. or less.

  In the present specification, the “active energy ray polymerizable monomer” means a polymerizable monomer having one or more ethylenically unsaturated double bonds (hereinafter sometimes referred to as “monomer”). .

[Monomer A): Monofunctional monomer having a glass transition point of −30 ° C. or lower]
The active energy ray-polymerizable monofunctional monomer is a monomer A) active energy ray-polymerizable monofunctional monomer having a glass transition point (Tg) of a homopolymer of less than −30 ° C. and having an ethylenically unsaturated double bond (hereinafter, Also referred to as “monomer A)”. ). Monomer A) can increase the flexibility and extensibility of the cured film. High flexibility means that the ink cured film is difficult to break when the substrate on which the ink composition cured film is formed is bent, and high extensibility means forming the ink composition cured film. This means that the cured film of the ink is not easily broken when the substrate is pulled (hereinafter the same).

  Examples of monomer A) include 2-ethylhexyl acrylate (Tg = −85 ° C.), 2-ethylhexyl carbitol acrylate (Tg = −65 ° C.), 2-methoxyethyl acrylate (Tg = −50 ° C.), 2-methoxybutyl. Acrylate (Tg = −56 ° C.), 4-hydroxybutyl acrylate (Tg = −80 ° C.), diethylene glycol monoethyl ether acrylate (Tg = −70 ° C.), ethoxydiethylene glycol acrylate (Tg = −70 ° C.), isoamyl acrylate (Tg) = -45 ° C), isodecyl acrylate (Tg = -55 ° C), isooctyl acrylate (Tg = -83 ° C), isotetradecyl acrylate (Tg = -56 ° C), caprolactone acrylate (Tg = -53 ° C), Methoxytripropylene glycol Lumpur acrylate (Tg = -75 ℃), EO (ethylene oxide) modified succinic acid acrylate (Tg = -40 ℃), tridecyl acrylate (Tg = -75 ° C.), and the like. Especially, it is preferable that it is one or more monomers selected from isooctyl acrylate, tridecyl acrylate, and ethoxydiethylene glycol acrylate from the point which is excellent in a softness | flexibility and adhesiveness, and has small cure shrinkage.

  The content of the monomer A) is preferably 2% by mass or more and 65% by mass or less, more preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass with respect to the total amount of the active energy ray polymerizable monomer. More preferably, it is 35 mass% or less. If it is less than 2% by mass, it is not preferable in that it cannot follow the elongation of the flexible substrate when printed on the flexible substrate, and the cured product of the ink composition may be cracked or peeled off. If it exceeds 65% by mass, it is not preferable in that the ink composition may be insufficiently cured when a predetermined active energy dose is applied to the ink composition.

[Monomer B): Polyfunctional monomer having a glass transition point of 0 ° C. or lower]
The active energy ray-polymerizable monofunctional monomer is also referred to as monomer B): a polyfunctional monomer having a glass transition point of 0 ° C. or less and having an ethylenically unsaturated double bond (hereinafter “monomer B”). ). Monomer B) contributes to the improvement of curability and has a low glass transition point, so that the balance between “curability” and “flexibility and extensibility” is good. Curability means that since it is polyfunctional, it is highly crosslinkable and a cured film can be formed with a small amount of active energy ray irradiation. When Tg exceeds 0 ° C., it is not preferable in that it cannot follow the elongation of the substrate to be printed when printing on an elastomer substrate or the like, and the cured product of the ink composition may be cracked or peeled off.

  Among the monomers B), as an example of a bifunctional monomer, 11 moles to 32 moles of ethylene oxide addition-modified product of bisphenol A (hereinafter referred to as “EO modification”), ethylene glycol repeat number n is 7 to 7. 14 polyethylene glycol diacrylate and polypropylene glycol diacrylate having a propylene glycol repeating number n of 7 to 14 are preferred, and more preferred examples include EO-modified (30) bisphenol A diacrylate (Tg = -42 ° C), polyethylene glycol diacrylate (n = 9, Tg = -20 ° C), polyethylene glycol diacrylate (n = 13-14, Tg = -34 ° C), polypropylene glycol diacrylate (n = 7, Tg) = -8 ° C), poly B propylene glycol diacrylate (n = 12, Tg = -32 ℃), and the like.

  Among the monomers B), examples of trifunctional monomers include EO-modified (3) trimethylolpropane triacrylate (Tg = −40 ° C.), EO-modified (6) trimethylolpropane triacrylate (Tg = −8 ° C.), EO Modification (9) Trimethylolpropane triacrylate (Tg = −19 ° C.), EO modification (15) Trimethylolpropane triacrylate (Tg = −32 ° C.), propylene oxide addition modification product (hereinafter referred to as “PO modification”) (3) Trimethylolpropane triacrylate (Tg = −15 ° C.), PO-modified (6) trimethylolpropane triacrylate (Tg = −15 ° C.) and the like.

  Among these, a bifunctional monomer having a Tg of −30 ° C. or less is preferable in terms of excellent flexibility and curability of the cured film, and polypropylene glycol diacrylate (n = 12, Tg = −32 ° C.), polyethylene glycol diacrylate (N = 13 to 14, Tg = −34 ° C.) and EO-modified (30) Bisphenol A diacrylate (Tg = −42 ° C.) is more preferable.

  The content of the monomer B) is preferably 2% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 15% by mass or less, and more preferably 9% by mass with respect to the total amount of the active energy ray polymerizable monomer. It is particularly preferably 15% by mass or less. When the amount is less than 2% by mass, a large amount of irradiation is required when the ink composition is cured by irradiating the ink composition with active energy rays, and there is a possibility that the ink composition cannot be sufficiently cured with a predetermined amount of active energy rays. When it exceeds 30% by mass, the viscosity is high, the crosslinkability becomes too high, and the followability and extensibility may be lowered.

  By containing both monomer A) and monomer B), both “flexibility and extensibility” and “curability” can be achieved. Only monomer A) or monomer B) cannot achieve both “flexibility and extensibility” and “curability”, and cannot provide an ink composition that follows a flexible substrate.

[Monomer C): Monofunctional monomer having an alicyclic structure having a glass transition point of 0 ° C. or higher and 110 ° C. or lower]
The active energy ray-polymerizable monofunctional monomer is also referred to as a monomer C): a monofunctional monomer having an alicyclic structure having a glass transition point of a homopolymer of 0 ° C. or higher and 110 ° C. or lower (hereinafter “monomer C”). ). By blending an appropriate amount of a monofunctional monomer having an alicyclic structure with a glass transition point in the above range, the flexibility and strength of the cured film are improved in a well-balanced manner.

  Examples of monomer C) are isobornyl acrylate (Tg = 94 ° C.), 4-t-butylcyclohexyl acrylate (Tg = 34 ° C.), cyclohexyl acrylate (Tg = 15 ° C.), dicyclopentenyloxyethyl acrylate (Tg = 14 ° C.). Among them, it is one or more monomers selected from isobornyl acrylate, 4-t-butylcyclohexyl acrylate, cyclohexyl acrylate, and dicyclopentenyloxyethyl acrylate in terms of improving the balance between flexibility and film strength. Is preferred.

  The content of the monomer C) is preferably 20% by mass or more and 65% by mass or less, based on the total amount of the active energy ray polymerizable monomer, in that the balance between flexibility and film strength can be appropriately improved. More preferably, it is 55 mass% or less. If it is less than 20% by mass, the film strength of the cured product may be lowered, which is not preferable. If it exceeds 65% by mass, the film strength is increased, but the followability to the substrate and the flexibility are lowered, and the balance between the film strength and the flexibility may be lowered.

  By adding monomer C) in addition to monomer A) and monomer B), “coating strength” is increased, and as a result, “flexibility and extensibility”, “curability”, and “coating strength”. A cured film satisfying all of the above can be obtained.

  Further, in addition to the monomers A) to C), another monomer may be appropriately added as long as the object of the present invention can be achieved. For example, phenoxyethyl acrylate (Tg = −22 ° C.), lauryl acrylate (Tg = −3 ° C.), 2-hydroxyethyl acrylate (Tg = −15 ° C.), stearyl acrylate (Tg = 30 ° C.), dicyclopentenyl acrylate ( Monofunctional monomer exemplified by Tg = 120 ° C., dicyclopentanyl acrylate (Tg = 120 ° C.), 1-adamantyl acrylate (Tg = 153 ° C.), etc., 1,4-butanediol diacrylate (Tg = 45 ° C.) ), Tetraethylene glycol diacrylate (Tg = 23 ° C.), dimethylol tricyclodecane diacrylate (Tg = 187 ° C.), trimethylol propane triacrylate (Tg = 62 ° C.), pentaerythritol triacrylate (Tg = 103 ° C.) Etc. Ma may also be added.

[Active energy ray polymerization initiator]
The active energy ray curable ink composition contains an active energy ray polymerization initiator. Active energy rays are energy rays that can trigger polymerization reactions such as radicals, cations, and anions. In addition to rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, electromagnetic waves such as X-rays and γ rays, electron beams Any of proton beam, neutron beam and the like may be used, but curing by ultraviolet irradiation is preferable from the viewpoints of curing speed, availability of an irradiation apparatus, price, and the like. The active energy ray polymerization initiator is not particularly limited as long as it accelerates the polymerization reaction of the compound having an ethylenically unsaturated double bond in the active energy ray-curable ink composition by irradiation with active energy rays, Conventionally known active energy ray polymerization initiators can be used. Specific examples of active energy ray polymerization initiators include, for example, aromatic ketones containing thioxanthone, α-aminoalkylphenones, α-hydroxyketones, acylphosphine oxides, aromatic onium salts, organic peroxides Thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

  In the present invention, the active energy ray polymerization initiator is composed of acylphosphine oxides, α-hydroxyketones, and α-aminoalkylphenones, among others, in order to accelerate the polymerization reaction and improve curability. It is preferable to use one or more selected from the group.

  Specific examples of acylphosphine oxide include bis (2,4,6-trimethylbenzoyl) -phenyl-phosphine oxide (trade name: Irgacure 819, manufactured by BASF Japan Ltd.), bis (2,6-dimethoxybenzoyl)- 2,4,4-trimethyl-pentylphenylphosphine oxide, (2,4,6-trimethoxybenzoyl) phosphine oxide (trade name: Lucillin TPO, manufactured by BASF Japan Ltd.) and the like.

  As a specific example of α-hydroxyketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one (commercial product) Name: Irgacure 127, manufactured by BASF Japan Ltd.), 2-hydroxy-4′-hydroxyethoxy-2-methylpropiophenone (trade name: Irgacure 2959, manufactured by BASF Japan Ltd.), 1-hydroxy-cyclohexyl-phenyl- Ketone (trade name: Irgacure 184, manufactured by BASF Japan Ltd.), oligo {2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone} (for example, trade names: ESACURE ONE, Lamberti Etc.).

  Specific examples of α-aminoalkylphenone include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name: Irgacure 369, manufactured by BASF Japan Ltd.), 2-dimethylamino -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (for example, trade name: Irgacure 379, manufactured by BASF Japan Ltd.) and the like.

  The amount of the active energy ray polymerization initiator may be an amount capable of appropriately starting the polymerization reaction of the active energy ray polymerizable monomer, and is 1% by mass or more and 20% by mass or less based on the entire active energy ray curable ink composition. It is preferable that it is 3 mass% or more and 20 mass% or less.

[Color material]
The active energy ray-curable ink composition of the present invention further contains a coloring material. The coloring material may be any inorganic pigment or organic pigment that is usually used in conventional oil-based ink compositions, such as carbon black, cadmium red, molybdenum red, chrome yellow, and cadmium yellow. , Titanium yellow, titanium oxide, chromium oxide, viridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, diketopyrrolopyrrole, anthraquinone, benzimidazolone, anthrapyrimidine, azo pigment, phthalocyanine pigment, quinacridone Pigment, isoindolinone pigment, dioxazine pigment, selenium pigment, perylene pigment, perinone pigment, thioindigo pigment, quinophthalone pigment, metal complex pigment, aluminum paste, silica, calcium carbonate, magnesium carbonate Beam, clay, precipitated barium sulfate, pearl pigments, and the like.

  A preferable dispersed particle diameter of the pigment of the active energy ray-curable ink composition is preferably 10 nm to 300 nm in terms of a volume average particle diameter by a laser scattering method. If it is less than 10 nm, the light resistance may be lowered, which is not preferable. On the other hand, if it exceeds 300 nm, it becomes difficult to stably maintain the dispersion, and when sedimentation of the pigment occurs, or when the inkjet ink is ejected by the inkjet recording apparatus, the head is clogged or the ejection bend occurs. It is not preferable.

  In the present invention, when a pigment is used, its content may be adjusted as appropriate. Although depending on the type of pigment, the content of the pigment in the entire inkjet ink composition is preferably 0.1 to 20% by mass in the case of an organic pigment from the viewpoint of achieving both dispersibility and coloring power. 10 mass% is more preferable. Moreover, from the point which balances a dispersibility and coloring power, in the case of an inorganic pigment, 1-40 mass% is preferable and 5-20 mass% is more preferable.

[Dispersant]
The active energy ray-curable ink composition preferably contains a dispersant for dispersing the color material. Examples of the dispersant include a polymer dispersant. The main chain of this polymer dispersant is made of polyester, polyacrylic, polyurethane, polyamine, polycaprolactone, etc., and the polymer dispersant has amino groups, carboxyl groups, sulfone groups, hydroxyl groups, etc. as side chains. It is preferable to have a polar group or a salt thereof.

  A preferred polymer dispersant is a polyester-based dispersant. Specific examples thereof include “SOLPERSE 33000” and “SOLPERSE 32000” and “SOLPERSE 24000” manufactured by Lubrizol Japan; “Dispersbyk 168” manufactured by BYK Chemie; Etc.

  The polymer dispersant is preferably 3 parts by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 60 parts by mass or less as an active ingredient with respect to 100 parts by mass of the color material. If the amount is less than 3 parts by mass, the color material cannot be uniformly dispersed, and the stability of the ink and the ejection property may be decreased. The ink stability means the stability of ink physical properties (for example, viscosity, particle size, etc.) when the ink composition is stored for a long period of time. When the amount exceeds 100 parts by mass, the curing component such as the polymerizable monomer is relatively decreased, and the curability may be lowered or the flexibility of the cured product may be lowered.

  The polymer dispersant is preferably 0.1% by mass or more and 30% by mass or less, and preferably 0.5% by mass or more and 20% by mass or less as an active ingredient with respect to the total amount of the ink composition. If it is less than 0.1% by mass, the coloring material cannot be uniformly dispersed, and the stability of the ink and the ejection property may be lowered, which is not preferable. If it exceeds 30% by mass, the curing component such as a polymerizable monomer is relatively decreased and the curability may be lowered, or the flexibility of the cured product may be lowered.

[Surface conditioner]
The active energy ray-curable ink composition may further contain a surface conditioner. Although it does not specifically limit as a surface conditioning agent, As a specific example, "BYK-306", "BYK-333", "BYK-371", "BYK-377", and Evonik Degussa Japan by the Big Chemie company which have dimethylpolysiloxane are included. “TegoRad2100”, “TegoRad2200N”, “TegoRad2300” and the like manufactured by the company can be mentioned.

  The content of the surface conditioner is preferably 0.1% by mass or more and 1% by mass or less based on the total amount of the ink composition. If it is less than 0.1% by mass, the surface tension of the ink is high, and the wettability to an elastomer substrate or the like is not preferable. Good wettability means that the ink composition wets and spreads without causing repelling when printing on a substrate. If it exceeds 1% by mass, the wetting tension of the cured product becomes low, which is not preferable in that repelling may occur when a surface protective layer is formed on the surface of the cured product.

[Other additives]
Moreover, the active energy ray-curable ink composition may contain various additives such as a plasticizer, a polymerization inhibitor, a light stabilizer, and an antioxidant as other additives. Although the solvent can be added within the range of achieving the object of the present application, it is most preferable not to contain it.

[viscosity]
The viscosity of the active energy ray-curable ink composition is preferably 5 mPa · s to 20 mPa · s at 40 ° C., more preferably 5 mPa · s to 15 mPa · s. When it is less than 5 mPa · s, it is not preferable in that the ejection property may be lowered when ejecting using an inkjet apparatus. Dischargeability means that normal printing cannot be performed due to ink dot missing or continuous discharge during continuous printing. If it exceeds 20 mPa · s, it is preferable in that the ink composition may not be normally ejected due to defective ejection due to missing dots even if a mechanism for reducing the viscosity by heating is incorporated in the head of the ink jet device. Absent.

  In addition, the surface tension of the active energy ray-curable ink composition of the present invention is preferably 20 to 40 mN / m at 40 ° C. from the viewpoint of inkjet dischargeability and discharge stability.

<Method for producing active energy ray-curable ink composition>
The method for producing the active energy ray-curable ink composition of the present invention is not particularly limited, and a conventionally known method can be used. First, using a disperser, the colorant is dispersed with an active energy ray polymerizable monomer, a dispersant, etc., and then an active energy ray polymerization initiator, a surface conditioner, etc. are added and stirred uniformly, and further with a filter. The active energy ray-curable ink composition of the present invention is obtained by filtering.

<Printed body manufacturing method>
The printed body of the present invention is produced by printing the active energy ray-curable ink composition on an elastomer substrate or a substrate to be printed having a Young's modulus of 0.001 MPa or more and 30 MPa or less by an ink jet method. This is done by curing with energy rays. The Young's modulus of the substrate to be printed may be 0.001 MPa or more and 30 MPa or less, but in the present invention, it can be suitably used when the Young's modulus is 0.001 MPa or more and less than 10 MPa. The printing is preferably an inkjet method. The spray method or brush coating method is not preferable in that the degree of freedom of decoration on the substrate to be printed is low.

[Substrate for printing]
The substrate to be printed may be any material as long as it is an elastomer substrate or a substrate to be printed having a Young's modulus of 0.001 MPa to 30 MPa. The elastomer substrate also includes a thermoplastic elastomer (hereinafter also referred to as “TPE”). TPE refers to a polymer material that is plasticized at a high temperature and can be injection-molded and processed like a plastic and exhibits properties of a rubber elastic body (elastomer) at room temperature.

  The TPE molecule may be a block polymer type in which a hard segment (plastic component) and a soft segment (elastic component) are chemically bonded in a single polymer, or a blend in which a hard segment and a soft segment are physically mixed. It may be a mold. Examples of TPE molecules include styrene, olefin, polyurethane and the like.

  Examples of styrene-based materials include SBS (styrene / butadiene / styrene block copolymer), SEBS (styrene / ethylene / butylene styrene block copolymer), and SEPS (styrene / ethylene / propylene / styrene block copolymer). It is done. As an example of the olefin, TPO (thermoplastic olefin) in which ethylene-propylene rubber is finely dispersed in polypropylene can be given. Further, examples of the polyurethane system include thermoplastic polyurethane (hereinafter also referred to as “TPU”).

  The present invention can sufficiently follow the elongation of the substrate to be printed even in the above-described substrate to be printed, and even when the substrate to be printed is repeatedly expanded and contracted, the cured formed on the surface thereof. It is characterized by being able to suppress cracking and peeling of the film.

[Curing with active energy rays]
The active energy ray is preferably light having a wavelength range of 200 to 450 nm, and more preferably light having a wavelength range of 250 to 430 nm. The light source is not particularly limited, and examples thereof include a high pressure mercury lamp, a metal halide lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, an ultraviolet laser, sunlight, and an LED lamp. By using these light sources and irradiating active energy rays so that the integrated light quantity is 100 mJ / cm ² or more, preferably 200 mJ / cm ² or more, the ink composition can be cured instantaneously.

  The thickness of the cured film (hereinafter referred to as “cured film”) obtained by curing the active energy ray-curable ink composition of the present invention is preferably 1 μm or more and 100 μm or less. If the thickness is less than 1 μm, the color density of the cured film containing the colorant may become thin, and the design and decorative properties may decrease, and physical properties such as adhesion and extensibility may decrease. . If it exceeds 100 μm, the ink composition may not be sufficiently cured in a short time when the ink composition is irradiated with active energy rays, which is not preferable.

  The cured film thickness is measured by applying an ink composition to a PET film (A4300, manufactured by Toyobo Co., Ltd.) under the same coating conditions as the prepared cured film, and measuring the thickness of the obtained cured film with a micrometer. did. The measurement was performed at 10 points per sample, and the average value of these was taken as the average film thickness. The same applies to the protective layer and primer described later.

  The active energy ray-curable ink composition of the present invention was formed as a cured film having a thickness of 10 microns on an SBR sheet having a thickness of 1 mm, and a cured film-forming substrate on which the cured film was formed was dumbbell-shaped No. 6. As a test piece of the shape (JIS K6251-5), the minimum elongation when cracking of the cured film occurs when a tensile test is performed at 25 ° C. and a tensile speed of 100 mm / min according to JIS K7161 is the elongation at break of the cured film. By definition, the elongation at break of the cured film is preferably 200% (for example, the elongation when the substrate is stretched three times the original is expressed as 200%) or more and 1000% or less. The active energy ray-curable ink composition of the present invention was formed as a cured film having a thickness of 10 microns on an SBR sheet having a thickness of 1 mm, and a cured film-forming substrate on which the cured film was formed was dumbbell-shaped No. 6. As a test piece of the shape (JIS K6251-5), the minimum elongation when cracking of the cured film occurs when a tensile test is performed at 25 ° C. and a tensile speed of 100 mm / min according to JIS K7161 is the elongation at break of the cured film. As defined, the elongation at break of the cured film is preferably 100% or more (for example, the elongation when the base material is stretched twice the original is expressed as 100%) or more, and preferably 200% or more. More preferably, it is preferably 1000% or less. The elongation at break of the cured film is 100% or more, so that it can sufficiently follow the elongation of the substrate to be printed, and the cured film formed on the surface even when the substrate to be printed expands and contracts Can be further suppressed. On the other hand, when the elongation at break of the cured film exceeds 1000%, it is difficult to increase the strength of the cured film.

  In addition, the active energy ray-curable ink composition of the present invention is formed as a cured film having a thickness of 10 μm on a 1 mm thick SBR sheet, and the elongation percentage of the cured film-forming substrate on which the cured film is formed is 100%. Even if the expansion / contraction of the cured film forming substrate is repeated 50 times at a strain rate of 100 mm / min so as to repeat the range from 1 to 200%, the cured film does not crack. Therefore, it is possible to sufficiently follow the elongation of the substrate to be printed, and even when the substrate to be printed expands and contracts, cracking and peeling of the cured film formed on the surface can be suppressed.

[Protection of cured film]
In order to further improve the durability of the printed body, it is preferable that a surface protective layer made of a surface protective agent is further formed on the surface of the cured film of the ink composition of the present invention. In particular, when the printed material is exposed outdoors, dust, dirt, mud, soot, pitch, etc. may adhere to it, and cracks may occur on the surface due to deterioration due to oxidation or ultraviolet rays, and gloss may be impaired. It is preferable that a surface protective layer made of a surface protective agent is formed on the surface of the cured film. The surface protective layer is not limited to being formed on the surface of the layer made of the cured film of the ink composition, but may be formed directly on the surface of the substrate to be printed, or on the surface of the substrate to be printed. You may form in the surface of the formed primer layer mentioned later.

  Examples of the surface protective layer include applying and drying an overcoat agent on the cured film of the ink composition to form a cured film, and laminating a film substrate on a substrate to be printed. When forming the surface protective layer, the surface of the cured film of the ink composition may have tackiness. Tack means that the surface of the cured film is sticky when touched with a finger. When an overcoat agent is used, it is a composition containing a silicone-modified (meth) acrylic emulsion having a Tg of 50 ° C. or less because of excellent followability to a substrate to be printed, scratch resistance, chemical resistance, and the like. preferable.

  The amount of the active ingredient in the silicone-modified (meth) acrylic emulsion of the overcoat agent is preferably 10 to 80%, more preferably 20 to 60%. When it is less than 10%, the drying time is long to form the protective layer, which is not preferable in terms of inferior productivity. When it is 80% or more, it is not preferable in that it may be difficult to apply the overcoat agent to the substrate to be printed.

  The thickness of the cured film is preferably 1 μm or more and 100 μm or less. If it is less than 1 μm, the cured film may not be properly protected, which is not preferable. If it exceeds 100 μm, the protective layer is formed, and thus the drying time becomes long, which is not preferable in terms of inferior productivity.

  As a commercial product of a resin composition for forming a surface protective layer containing a silicone-modified (meth) acrylic emulsion, OP-11, OP-13, OP-39, OP-53, OP-55 (all manufactured by DNP Fine Chemical Co., Ltd.) Is mentioned. Since the Tg of the silicone-modified (meth) acrylic emulsion containing any of these is 50 ° C. or less, the elongation of the cured film is good. Further, even under conditions where repeated stress is applied, it has high followability to the substrate to be printed.

[Improved adhesion between printed substrate and cured film]
In order to increase the adhesion between the elastomer substrate or the substrate to be printed having a Young's modulus of 0.001 MPa to 30 MPa and the cured film of the active energy ray-curable ink composition of the present invention, A primer layer may be formed between them.

  Examples of the primer composition constituting the primer layer include a resin composition containing the above silicone-modified (meth) acrylic emulsion or chlorinated polyolefin. Primer composition comprising a silicone-modified (meth) acrylic emulsion having a Tg of 50 ° C. or less in terms of adhesion to a substrate to be printed, followability, adhesion to an active energy ray-curable ink composition, flexibility, etc. Is preferred. Moreover, in order to improve adhesiveness, you may add a hardening | curing agent to a primer composition.

  The amount of the active ingredient in the silicone-modified (meth) acrylic emulsion of the primer composition is preferably 10 to 80%, more preferably 20 to 60%. If it is less than 10%, the drying time is long to form the primer layer, which is not preferable in terms of inferior productivity. When it is 80% or more, it is not preferable in that it may be difficult to apply the primer composition.

  A polyisocyanate is mentioned as a hardening | curing agent. It is preferable that content of a hardening | curing agent is 1 to 50 mass parts with respect to 100 mass parts of primer compositions. If it is less than 1 part by mass, the adhesiveness may not be significantly improved even if a curing agent is added. If the amount exceeds 50 parts by mass, the followability to the substrate to be printed may be lowered, which is not preferable.

  When the substrate to be printed is colored, it is preferable that the primer composition contains a hiding pigment such as a white pigment such as titanium oxide, an aluminum paste, or a pearl pigment in order to improve designability and color developability after printing. . In particular, a primer composition containing titanium oxide is preferable in order to improve design properties and color developability after printing.

  When the primer composition contains titanium oxide, the content of titanium oxide is preferably 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the primer composition. If the amount is less than 1 part by mass, there is a possibility that the design and color developability after printing are not significantly improved. When the amount exceeds 50 parts by mass, the other resin components are reduced, and the followability of the cured film may be reduced.

  The thickness of the primer layer is preferably 1 μm or more and 100 μm or less. If it is less than 1 μm, even if a primer layer is provided, the adhesion between the substrate surface and the cured film of the active energy ray-curable ink composition may not be significantly improved, or it contains a concealing pigment. In the case of a primer layer, it is not preferable because the designability and color development after printing may not be significantly improved. If it exceeds 100 μm, the drying time for curing the primer composition becomes longer, which is not preferable in terms of poor productivity.

  Examples of commercially available primer compositions include PR-12 and PR-13 (both manufactured by DNP Fine Chemical Co.) containing titanium oxide and silicone-modified (meth) acrylic emulsion.

  In addition, when forming a surface protective layer or a primer layer on a substrate to be printed, any method may be used as long as the composition is uniformly applied. For example, spray coating, towel, sponge, nonwoven fabric Application using a tissue or the like, dispenser, brush coating, gravure printing, flexographic printing, silk screen printing, inkjet, thermal transfer method, etc. may be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention does not receive a restriction | limiting at all in these description.

  <Preparation of Ink Composition (Examples 1 to 31, Comparative Examples 1 to 9)>

（単位は質量％）

(Unit is mass%)

〔分散体の調製〕
まず、白色以外の黄色・紅色・藍色・黒色については、表１−１及び１−２に示す割合の分散剤を単官能モノマーに溶解し、表１−１及び１−２に示す割合の顔料を加えた。ここで使用する単官能モノマーの量は、顔料濃度が１２％となるようにする。そして、混合液を、ペイントシェーカーを用いて顔料の体積平均径が３００ｎｍ以下となるように分散し、分散体を得た。粒子径は、レーザー散乱法を利用した粒度分布測定器である、マイクロトラック粒度分析計ＵＰＡ１５０（日機装社製）を用いて測定した。また、白色インクについては顔料濃度が４０％となるように行う以外は同様の方法で行った。 The details of carbon black, polymer dispersant A, and polymer dispersant B are as follows.

(Preparation of dispersion)
First, for yellow, red, indigo and black other than white, the dispersants in the ratios shown in Tables 1-1 and 1-2 are dissolved in the monofunctional monomer, and the ratios shown in Tables 1-1 and 1-2 are dissolved. Pigment was added. The amount of the monofunctional monomer used here is such that the pigment concentration is 12%. And the liquid mixture was disperse | distributed so that the volume average diameter of the pigment might be 300 nm or less using the paint shaker, and the dispersion was obtained. The particle size was measured using a Microtrac particle size analyzer UPA150 (manufactured by Nikkiso Co., Ltd.), which is a particle size distribution measuring device using a laser scattering method. For white ink, the same method was used except that the pigment concentration was 40%.

[Preparation of ink composition]
Subsequently, the other raw materials were mixed so as to have the ratios shown in Tables 1-1 and 1-2, and stirred for 1 hour while heating to 50 ° C. Then, after confirming that there was no undissolved residue and returning to room temperature, a dispersion prepared in advance was added and stirred for 1 hour. Then, it filtered using a membrane filter and prepared the ink composition of Examples 1-31 and Comparative Examples 1-9.

<Manufacture of printed materials (Examples 1 to 43, Comparative Examples 1 to 9)>

1. Manufacture of Printed Body According to Example A printed body was manufactured using an SBR sheet having a thickness of 1 mm and a thermoplastic polyurethane sheet having a thickness of 0.3 mm (hereinafter referred to as “TPU sheet”) as a base material. On the surface of the substrate, the composition constituting the decorative print layer shown in Table 3 was printed by the ink jet method under the condition of resolution 720 dpi so that the average film thickness was the thickness shown in Table 3 (for the layer structure, see Table 1). 4-1 and 4-2, thereby producing Examples 1 to 43). Then, using a SubZero system (UV lamp system, manufactured by Integration Technology, D bulb, output 100 W / cm), the integrated light quantity is 640 mJ / cm ² , the peak illuminance is 640 mW / cm ² , and the conveyance speed is 18 m / min. The ink composition was cured. The measurement of the integrated light quantity and peak illuminance was performed using an ultraviolet light quantity meter UV-351 (manufactured by Oak Manufacturing Co., Ltd.). Thereby, the decorative printing layer was produced.

2. Production of Printed Body According to Comparative Example Comparative Examples 1 to 9 were printed at a resolution of 720 dpi to produce a decorative print layer.

  Hereinafter, evaluation of various items will be described. In the evaluation, there are places where “○ ・ ×” evaluation and “○ ・ △ ・ ×” evaluation are performed, but as a practical range of evaluation results, “○ ×” evaluation is ○,・ In the “X” evaluation, “◯” or “△” is given.

[Evaluation of adhesion]
The evaluation of adhesion was performed as follows. A cellophane adhesive tape is applied to the decorative print layer after curing, and after the cellophane tape is peeled off at 90 degrees, the decorative print layer and the cellophane adhesive tape are sufficiently adhered to the base material. The degree of adhesion was judged. The results are shown in Tables 4-1 to 4-3. The case where there was no peeling was indicated as “◯”, and the case where there was peeling was indicated as “x”.

[Evaluation of curability]
The evaluation of curability was performed by touching the cured coating film with a finger and confirming the curing speed and ink adhesion. The results are shown in Tables 4-1 to 4-3. The case where the ink cured quickly and the ink did not adhere was marked with “◯”, the case where the curing took a long time but the ink did not adhere was marked with “Δ”, and the case where the ink cured slowly and the ink adhered was marked with “X”.

[Evaluation of tack]
Evaluation of tack was performed at room temperature.
The printed body was placed at room temperature, and the coating film was touched with a finger to check for stickiness. The results are shown in Tables 4-1 to 4-3. The case where there was no stickiness was set as “◯”, the case where there was a little stickiness was set as “Δ”, and the case where stickiness was strong was set as “X”.

[Evaluation of bending resistance]
The bending resistance was evaluated by a 90 ° bending test. The 90 ° bending test was performed by visually evaluating the presence or absence of cracks in the cured film when the printed bodies of Examples and Comparative Examples were bent at 90 °. The results are shown in Tables 4-1 to 4-3. The case where there was no crack was indicated as “◯”, the case where a crack was observed in a very small part was indicated as “Δ”, and the case where a crack was observed on the entire surface was indicated as “X”.

[Evaluation of elongation]
Evaluation of elongation rate was performed as follows. When the printed bodies of the examples and comparative examples were dumbbell-shaped No. 6 (JIS K6251-5) test pieces and were subjected to a tensile test at 25 ° C. and a tensile rate of 100 mm / min according to JIS K7161, the cracks in the cured film were observed. The elongation at break of the cured film at which rupture occurs was measured. The elongation at break of the cured film was calculated from (the length of the printed body when the crack of the cured film occurred−the original length of the printed body) / the original length of the printed body × 100. The results are shown in Tables 4-1 to 4-3.

[Evaluation when the printed material is repeatedly stretched]
When the prints of Examples and Comparative Examples were repeatedly expanded and contracted 50 times at a strain rate of 100 mm / min so as to repeat the range of elongation from 100% to 200%, cracks in the cured film occurred. Confirmed whether or not. The elongation was calculated from (length of printed body when crack of cured film occurred−original length of printed body) / original length of printed body × 100. The results are shown in Tables 4-1 to 4-3. When the crack of the cured film did not occur, “◯” was indicated, when a part of the crack was observed, “△”, and when crack or peeling was observed, “X”.

[Evaluation of water resistance]
The water resistance was evaluated by immersing the printed body in tap water at room temperature for 1 week, and performing the 90 ° bending test with the printed body remaining wet. Moreover, it immersed for 1 week and evaluated the external appearance of the printed body after drying. The results are shown in Tables 4-1 to 4-3. The 90 ° bending test was evaluated in the same manner as in the above [Evaluation of Bending Resistance]. As for the appearance, “○” indicates that there was no change, “△” indicates that there was a change but no peeling of the coating film, and “×” indicates that the coating peeling was observed. .

[Evaluation of scratch resistance]
The scratch resistance was evaluated by evaluating the appearance when the sample was rubbed 100 times with a polybrush. The results are shown in Tables 4-1 to 4-3. The case where there was no change in the appearance was indicated by “◯”, the case where the coating film was scratched was indicated by “Δ”, and the case where the coating film was peeled was indicated by “X”.

  Monomer A): a cured film of an active energy ray-curable ink composition containing a monofunctional monomer having a glass transition point of −30 ° C. or less and monomer B): a polyfunctional monomer having a glass transition point of 0 ° C. or less. It was confirmed that the printed body on which a certain decorative printing layer was formed could prevent cracks and peeling from entering the decoration even when the expansion and contraction was repeated at all times (Examples 1 to 43). Moreover, since the decoration was directly printed on the flexible base material by the inkjet method, the degree of freedom of decoration on the flexible base material can be increased.

  It can be seen from Tables 4-1 to 4-3 that the following tendencies are generally obtained. Examples 1 to 6 contain monomer A) and monomer B) but do not contain monomer C). As a result, although it has good results, scratch resistance is inferior compared to the case of containing monomer C) in addition to monomer A) and monomer B) (Examples 7 to 27). In particular, Examples 4 to 6 are inferior in elongation at break of the cured film as compared with other examples because the Tg of the monomer B is high.

  Examples 7 to 27 are cases in which monomer C) is contained in addition to monomer A) and monomer B), and in terms of scratch resistance compared to the case of monomer A) and monomer B) only (Examples 1 to 6). Is preferred. Examples 28-31 contain monomer A), monomer B), and monomer C), but the content of any monomer is close to the upper limit or lower limit, so any of tack, scratch resistance, elongation evaluation, or curability is selected. Is inferior to Examples 7-27. This will be described in detail below.

  Regarding the curability, when the amount of monomer A) is 50% by mass or less based on the total amount of active energy ray polymerizable monomer (Examples 7 to 27, etc.), the amount of monomer A) becomes the total amount of active energy ray polymerizable monomer. On the other hand, it was confirmed that the curability was excellent as compared with the case of exceeding 50 mass% (Example 29). Further, when the amount of monomer B) exceeds 5% by mass with respect to the total amount of the active energy ray polymerizable monomer (Examples 7 to 27), the content of monomer B) is 5 parts by mass or less (Examples). Compared with 30), it was confirmed that the curability is excellent.

  Regarding tack, when the amount of monomer A) is 50% by mass or less based on the total amount of active energy ray polymerizable monomer (Examples 7 to 27, etc.), the amount of monomer A) is based on the total amount of active energy ray polymerizable monomer. Thus, it was confirmed that the stickiness was small as compared with the case of exceeding 50 mass% (Example 29). This is considered to be because when the amount of the monomer A) exceeds 50% by mass with respect to the total amount of the active energy ray polymerizable monomer, the Tg as the ink composition becomes too low.

  Regarding the extensibility, when the amount of the monomer A) is 5% by mass or more with respect to the total amount of the active energy ray polymerizable monomer (Examples 7 to 27), the amount of the monomer A) becomes the total amount of the active energy ray polymerizable monomer. On the other hand, compared with the case where it is less than 5 mass% (Example 28), it was confirmed that the cured film was excellent in elongation at break and repeatability of expansion and contraction. When the amount of monomer B) is 20% by mass or less based on the total amount of active energy ray polymerizable monomer (Examples 7 to 27, etc.), the amount of monomer B) is based on the total amount of active energy ray polymerizable monomer. Compared with the case where it exceeds 20 mass% (Example 31), it was confirmed that the cured film was excellent in elongation at break and repeatability of expansion and contraction. The elongation at break of the SBR sheet is 650%, and the elongation at break of the TPU sheet is 400%. That is, in the evaluation, the elongation at break was 650% or 400% because the base material was not a cured film, and the cured film formed from the ink composition of the present invention had a base material. Even if it breaks, it has extensibility that can still be extended.

  Regarding scratch resistance, when the amount of monomer A) is 50% by mass or less based on the total amount of active energy ray polymerizable monomer (Examples 7 to 27, etc.), the amount of monomer A) becomes the total amount of active energy ray polymerizable monomer. On the other hand, it was confirmed that the scratch resistance was excellent as compared with the case where it exceeded 50 mass% (Example 29). In addition to monomers A) and B), monomer C): a monomer having a alicyclic structure with a glass transition point of 0 ° C. or higher and 110 ° C. or lower (Examples 7 to 27, etc.), monomer It was confirmed that it was superior in scratch resistance as compared with the case where C) was not contained (Examples 1 to 6). From this, it can be said that the addition of the monomer C) increases the strength of the cured film.

  In Examples 32-43, inks of a plurality of colors are overlaid and printed. When printing with multiple color inks, the decorative print layer is thicker than when printing single color inks only once, but in this case it was also confirmed that each physical property was not affected. It was. It was also confirmed that there was no difference in physical properties depending on the colors to be superimposed. It is preferable to print with overlapping inks because color development and design properties are improved. In particular, it is preferable to use a white ink as the underprinting ink because the color developability and design properties of the overprinting ink are improved.

  On the other hand, when the monomer A) was not contained, it was confirmed that the elongation at break of the cured film was remarkably inferior, and the flex resistance and the repeatability of expansion and contraction were also inferior (Comparative Examples 1 to 3). As a result, when printing on the flexible substrate, the elongation of the flexible substrate cannot be followed, and the cured product of the ink composition may be cracked or peeled off. Moreover, when the monomer B) was replaced with a monofunctional monomer, it was confirmed that curability was remarkably lowered, and accordingly, tack and scratch resistance were also lowered (Comparative Examples 4 to 6). Moreover, when the monomer B) was replaced with a monomer having a high Tg, it was confirmed that sufficient elongation at break of the cured film was not obtained and the repeatability of expansion and contraction was inferior (Comparative Examples 7 to 9).

<Examples 44 to 61>

Details of the raw materials are as follows.

[Manufacture of printed materials]
In order to use for table evaluation, a printed body was produced using a 1 mm thick SBR sheet as a base material. About the composition which comprises the primer layer shown in Table 5, it apply | coated on the said rubber | gum base material using the bar-coater # 20 so that the average film thickness after drying might be 10 micrometers. And it was made to dry on 120 degreeC conditions for 1 minute. Through the above steps, a primer layer was obtained.

Subsequently, the composition constituting the decorative print layer shown in Table 5 was printed on the surface of the primer layer by an inkjet method so that the average film thickness was the film thickness shown in Table 5. Then, using a SubZero system (UV lamp system, manufactured by Integration Technology, D bulb, output 100 W / cm), the integrated light quantity is 640 mJ / cm ² , the peak illuminance is 640 mW / cm ² , and the conveyance speed is 18 m / min. The ink composition was cured. The measurement of the integrated light quantity and peak illuminance was performed using an ultraviolet light quantity meter UV-351 (manufactured by Oak Manufacturing Co., Ltd.). Thereby, the decorative printing layer was produced.

  Then, the composition which comprises the surface protective layer shown in Table 5 was apply | coated to the surface of a decorating printing layer so that the average film thickness after drying might be set to 10 micrometers using bar coater # 20. And it was made to dry on 120 degreeC conditions for 1 minute. Through the above steps, a surface protective layer was obtained and printed bodies of Examples 44 to 61 were obtained.

[Evaluation]
In addition to the items evaluated in Example 1 etc. for the printed matter, the scratch resistance is not only the appearance when the sample is rubbed 100 times with a polybrush, but also when the sample is rubbed 100 times (one way) with a brass brush. Appearance and appearance when the film was scratched with a nail at room temperature were also evaluated. The results are shown in Table 7. The case where there was no change in the appearance was indicated by “◯”, the case where the coating film was scratched was indicated by “Δ”, and the case where the coating film was peeled was indicated by “X”.

  About Examples 44-49, it was confirmed by forming a surface protective layer on the surface of a decorative printing layer that water resistance, scratch resistance, etc. improve further compared with Examples 1-3 and 11. Moreover, about Example 53-61, even if it was a case where a primer layer was formed between the flexible base material surface and the decorative printing layer, it was confirmed that performance is not inferior.

  About Examples 50-52, even if it was a case where the kind of monomer which the ink composition which comprises a decorative printing layer contains differs, it was confirmed that a performance is not inferior compared with Examples 44-49. . Moreover, it was confirmed that the formation of the surface protective layer is effective not only for water resistance and scratch resistance (poly brush) but also for improving other resistance such as detergent resistance and chemical resistance.

Claims (14)

Containing an active energy ray polymerizable monomer and an active energy ray polymerization initiator,
As the active energy ray polymerizable monomer,
Monomer A): a monofunctional monomer having a glass transition point of −30 ° C. or lower,
Monomer B): an active energy ray-curable ink composition containing a polyfunctional monomer having a glass transition point of 0 ° C. or lower.   The active energy ray-curable ink composition according to claim 1, wherein the monomer B) is a bifunctional monomer having a glass transition point of -30 ° C or lower. Among the active energy ray polymerizable monomers,
2 to 65% by weight of monomer A)
2 to 30% by weight of the monomer B)
The active energy ray-curable ink composition according to claim 1, which is contained. As the active energy ray polymerizable monomer,
Monomer C): The active energy ray-curable ink composition according to any one of claims 1 to 3, further comprising a monofunctional monomer having an alicyclic structure having a glass transition point of 0 ° C or higher and 110 ° C or lower.   The active energy ray-curable ink composition according to claim 4, wherein the monomer C) is contained in an amount of 20 to 65% by mass of the active energy ray polymerizable monomer. The monomer A) is any one or more monomers selected from isooctyl acrylate, tridecyl acrylate and ethoxydiethylene glycol acrylate;
The monomer B) is any one or more monomers selected from polypropylene glycol diacrylate, polyethylene glycol diacrylate and EO-modified bisphenol A diacrylate,
6. The active energy according to claim 4 or 5, wherein the monomer C) is any one or more monomers selected from isobornyl acrylate, 4-t-butylcyclohexyl acrylate, cyclohexyl acrylate and dicyclopentenyloxyethyl acrylate. Line curable ink composition.   The active energy ray-curable ink composition according to claim 1, further comprising a coloring material.   The active energy ray-curable ink composition according to claim 1 is formed as a cured film having a thickness of 10 μm on a styrene butadiene rubber (hereinafter referred to as “SBR”) sheet having a thickness of 1 mm. When the cured film-formed substrate on which this cured film was formed was subjected to a tensile test at 25 ° C. and a tensile speed of 100 mm / min as a dumbbell-shaped No. 6 type (JIS K6251-5) test piece, The active energy ray-curable ink composition according to claim 1, wherein an elongation at break of a cured film at which the cured film is cracked is 200% or more.   The active energy ray-curable ink composition is formed on a 1 mm thick SBR sheet as a cured film having a thickness of 10 μm, and the elongation percentage of the cured film forming substrate on which the cured film is formed is 100% to 200%. The activity according to any one of claims 1 to 8, wherein the cured film does not crack when the expansion / contraction of the cured film-forming substrate is repeated 50 times at a strain rate of 100 mm / min so as to repeat the above range. Energy ray curable ink composition.   The active energy ray-curable ink composition according to any one of claims 1 to 9, wherein the active energy ray-curable ink composition is used as an inkjet ink for an elastomer substrate or a substrate to be printed having a Young's modulus of 0.001 MPa to 30 MPa.   The ink cured film which is a cured film of the active energy ray-curable ink composition according to any one of claims 1 to 10 on an elastomer substrate or a substrate to be printed having a Young's modulus of 0.001 MPa to 30 MPa. Printed body on which a layer is formed.   The printed body according to claim 11, wherein a surface protective layer for protecting a surface of the ink cured film layer is formed on a surface of the ink cured film layer.   The printed body according to claim 11 or 12, wherein a primer layer is formed between the surface of the elastomer substrate or the substrate to be printed and the ink cured film layer.   After printing the active energy ray-curable ink composition according to any one of claims 1 to 9 on an elastomer substrate or a substrate to be printed having a Young's modulus of 0.001 MPa to 30 MPa by an inkjet method, A method for producing a printed material, which is cured by ultraviolet rays.