JP5862022B2 - Inkjet recording method, UV curable inkjet ink and liquid. - Google Patents

Description

  The present invention relates to an ink jet recording method.

Conventionally, various methods have been used as a recording method for forming an image on a recording medium based on an image data signal. Among these, the ink jet system is an inexpensive apparatus, and ink is ejected only to a required image portion to form an image directly on a recording medium. Therefore, the ink can be used efficiently, and the running cost is low.

In recent years, in order to form good images such as water resistance, solvent resistance, and abrasion resistance on the surface of a recording medium, an ultraviolet curable inkjet ink that is cured when irradiated with ultraviolet rays is used in an inkjet recording method. Has been.

For example, Patent Document 1 provides an ink jet recording method capable of obtaining an ink jet recording medium having a high color density and a small hue change and a high density recorded image and suppressing a hue change immediately after printing. In addition, a non-water-absorbing support such as a polyolefin resin (PP, PE) or the like has at least two or more ink receiving layers containing vapor-phase silica as inorganic fine particles and polyvinyl alcohol as a water-soluble resin. Is disclosed.

For example, Patent Document 2 discloses an inkjet having an ink receiving layer containing inorganic fine particles, a water-soluble resin, and a cross-linking agent on a support in order to obtain an image having a high density and a suppressed color difference (color change). A recording medium for use, a conveying means for conveying the recording medium, an ejection means for ejecting ink containing a dye, water, and a water-soluble organic solvent, and a drying means for drying the ink applied to the recording medium; And an inkjet recording method using the same.

Further, for example, Patent Document 3 discloses an inkjet recording medium provided with an ink receiving layer containing a pigment and a binder in order to obtain a high-quality, high-rubber recorded image. An inkjet recording medium containing a polyvinyl alcohol having a contact angle with respect to glycerin of the outermost layer of 45 ° or less and a saponification degree of 90 mol% or less and a modified product thereof as a binder, and An ink jet recording method used is disclosed.

JP 2010-76179 A JP 2010-69870 A JP 2007-216509 A

However, the techniques disclosed in Patent Documents 1 to 3 are inferior or have room for improvement in at least one of ink curability and line width when printed.

Accordingly, an object of the present invention is to provide an ink jet recording method excellent in both the curability of ink and the line width when printed.

The present inventors have intensively studied to solve the above problems. As a result, Japanese Industrial Standards (JIS
On the recording medium having a surface roughness (Rq value [square root height]) defined based on B0601) of 1 or more, an undercoat layer is provided using a resin-containing liquid, and then the recording medium By attaching an ultraviolet curable inkjet ink containing a compound having both a vinyl group and a (meth) acryl group in the molecule to the undercoat layer side, both the curability of the ink and the line width when printed As a result, the present invention was completed.

That is, the present invention is as follows.
[1]
A step of providing an undercoat layer using a resin-containing liquid on a recording medium having a surface roughness of 1 or more, and the undercoat layer side of the recording medium provided with the undercoat layer has the following general formula: (I)
:
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. Group.)
And a step of adhering an ultraviolet curable ink-jet ink containing a compound represented by formula (1) to the recording medium.
[2]
[1] The resin is at least one of an acrylic resin and a urethane resin.
The ink jet recording method described in 1.
[3]
The step of providing the undercoat layer is an ink jet recording method according to [1] or [2], wherein the undercoat layer is provided using the resin dispersion.
[4]
The step of providing the undercoat layer includes applying at least one dispersion liquid of the acrylic resin and the urethane resin.
[5]
The inkjet recording method according to any one of [1] to [4], wherein the thickness of the undercoat layer is 5 to 20 μm.
[6]
The inkjet recording method according to any one of [1] to [5], wherein the ultraviolet curable inkjet ink is attached to the recording medium under a condition of 0.7 mg / inch ² or less.
[7]
The ultraviolet curable inkjet ink according to any one of [1] to [6], containing 10 to 87% by mass of 2- (vinyloxyethoxy) ethyl acrylate with respect to the total mass of the ink. Inkjet recording method.
[8]
[1] The viscosity of the ultraviolet curable ink-jet ink is 15 mPa · s or less.
-The inkjet recording method in any one of [7].

Hereinafter, embodiments for carrying out the present invention will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

In this specification, “curability” refers to a property of curing in response to light. "Tackiness"
The term “characteristic” refers to the property that no scratch marks are made even when rubbed with a cotton swab. More specifically, when the surface of the recording medium having the undercoat layer is touched with a finger, the surface does not adhere to the finger due to the viscosity of the surface (tack).

In this specification, “surface roughness” means surface roughness defined based on JIS B0601;
That is, it means an Rq value (square root height). Here, JIS B0601 is ISO
Corresponding to 4287, "Geometrical Product Specifications (GPS)-Surface Properties: Contour Curve Method-Terminology, Definitions and Surface Properties Parameters"
exture: Profile method-Terms, definitions and surface texture parameters). Among these, the root mean square height (Rq) represents the root mean square height in the reference length, and means the standard deviation of the surface roughness.

In this specification, “(meth) acrylate” means at least one of acrylate and its corresponding methacrylate, and “(meth) acryl” means at least one of acryl and its corresponding methacryl.
In this specification, “application” means application to a surface, and the application method is not limited, but specifically, by a roller coating method, a spin coating method, a dipping method, a spray method, an inkjet method, or the like. Means painting on the surface.

[Inkjet recording method]
In an ink jet recording method according to an embodiment of the present invention, a resin-containing liquid (hereinafter also referred to as “anchor agent”) is used for undercoating on a recording medium having a surface roughness (Rq) of 1 or more. A step of providing a layer (hereinafter also referred to as “undercoat layer forming step”) and a vinyl group and a (meth) acryl group in the molecule on the undercoat layer side of the recording medium provided with the undercoat layer. And a step of adhering an ultraviolet curable ink-jet ink containing the compound to the recording medium (hereinafter also referred to as “ink adhering step”). Hereinafter, each step will be described in detail.

[Undercoat layer forming step]
In the undercoat layer forming step, an undercoat layer is formed by applying an anchor agent (base material) containing a resin onto a recording medium having an Rq of 1 or more and then drying it as desired. The anchor agent may be applied using a roll coater or the like. The conditions for drying the anchor agent as desired are not particularly limited as long as the anchor agent is sufficiently dried. For example, the anchor agent may be dried at 40 to 60 ° C. for 3 to 4 minutes.

The thickness of the undercoat layer after coating (after drying when dried) is preferably 5 to 20 μm, and more preferably 5 to 10 μm. When the thickness is within the above range, the curability of the ink and the line width upon printing are further improved.

(Recording medium)
The recording medium used in the undercoat layer forming step has a surface roughness (Rq) of 1 or more. When Rq is within the above range, it is excellent in practical use, such as being able to describe characters with a pencil. In addition, the measurement of Rq in this specification shall be performed by the method used in the below-mentioned Example.

Examples of the recording medium include an absorbing or non-absorbing recording medium. The ink jet recording method of the present embodiment has various absorption performances from a non-absorbable recording medium in which penetration of a water-soluble anchor agent is difficult to an absorbent recording medium in which penetration of a water-soluble anchor agent is easy. Can be widely applied to recording media having However, when the anchor agent is applied to a non-absorbable recording medium, it may be necessary to provide a drying step after being cured by irradiation with ultraviolet rays.

The absorbent recording medium is not particularly limited. For example, plain paper and high-quality paper such as electrophotographic paper having high penetrability of a water-soluble anchor agent, ink jet paper (absorption composed of silica particles and alumina particles). Art paper used for general offset printing in which the permeability of a water-soluble anchor agent is relatively low), and an ink-dedicated paper having an absorption layer composed of a hydrophilic polymer such as polyvinylpyrrolidone (PVP)) , Coated paper, and cast paper.

The non-absorbable recording medium is not particularly limited. For example, plastic films and plates such as polyvinyl chloride, polyethylene, polystyrene (PS), polypropylene (PP), and polyethylene terephthalate (PET), and plastic are mainly used. Examples include synthetic paper, iron, silver, copper, and aluminum plates as raw materials, metal plates produced by vapor deposition of these various metals, plastic films, and stainless steel and brass alloy plates. It is done. Examples of commercially available non-absorbable recording media include YUPO (
New Yupo "FGS series" (registered trademark) paper (Yupo C
orporation), synthetic paper, surface roughness 1.446), PET50 (K2411) PAT1
E (Lintec Corporation product name, foamed PET film, surface roughness
112).

(Anchor agent)
The undercoat layer in this embodiment can be provided by applying the anchor agent (base material) to a recording medium.

As the resin contained in the anchor agent, those listed below are preferable. Resin may be used individually by 1 type and may be used in combination of 2 or more type.

As said resin, the thermoplastic resin conventionally used in the anchor agent can be used. Specific examples of this thermoplastic resin include, but are not limited to, urethane resins or copolymers thereof, and poly (meth) acrylic acid esters (acrylic resins) or copolymers thereof, polyacrylonitrile or copolymers thereof, poly (Meth) acrylic polymers such as cyanoacrylate, polyacrylamide, and poly (meth) acrylic acid, polyethylene,
Polypropylene, polybutene, polyisobutylene, and polystyrene, and copolymers thereof, and polyolefin polymers such as petroleum resins, coumarone-indene resins, and terpene resins, polyvinyl acetate or copolymers thereof, polyvinyl alcohol (PVA) , Vinyl acetate or vinyl alcohol polymers such as polyvinyl acetal, and polyvinyl ether, polyvinyl chloride or copolymers thereof, polyvinylidene chloride, fluororesins, and halogen-containing polymers such as fluoro rubber, polyvinyl carbazole, polyvinyl Pyrrolidone or copolymers thereof, nitrogen-containing vinyl polymers such as polyvinyl pyridine and polyvinyl imidazole, polybutadiene or copolymers thereof, polychloroprene, and polyisoprene (
Diene polymers such as butyl rubber), other ring-opening polymerization resins, condensation polymerization resins,
And natural polymer resins.

Among these, in order to further improve the tackiness, at least one of a urethane resin or a copolymer thereof and a (meth) acrylic polymer is preferable, and at least one of a urethane resin and an acrylic resin is more preferable.

The resin in the anchoring agent can be included as a solution or dispersion. That is, the undercoat layer forming step preferably includes providing an undercoat layer using a resin solution or dispersion. Examples of the resin contained in the dispersion include emulsions and suspensions. Examples of the solvent for the solution and the dispersion medium for the dispersion include water and an organic solvent. Examples of the dispersion include an aqueous dispersion in which water is the maximum mass as a dispersion medium, and a solvent dispersion in which an organic solvent is the maximum mass as the dispersion medium.
Among the liquids containing the above resins, a dispersion is preferable because of excellent tackiness and the like, and among these, an aqueous dispersion is more preferable. Moreover, since it is excellent in water resistance, the water dispersion type emulsion which is an aqueous dispersion of an emulsion, ie, an aqueous emulsion, is further preferable. More specifically, these resins need to be water-dispersible even when insoluble in water. Therefore, these resins are polymers having both a hydrophilic part and a hydrophobic part, that is, an aqueous emulsion (aqueous resin emulsion). Preferably there is. When an aqueous emulsion is used as the thermoplastic resin, the average particle size is not particularly limited as long as the emulsion is formed, but is preferably about 150 nm or less, more preferably about 5 nm to 100 nm.

When the anchor agent is used as a dispersion, a thermoplastic resin that has been conventionally used in the anchor agent can be used as the resin to be dispersed. Among these, at least one of the acrylic resin and the urethane resin is preferable because it is further excellent in tackiness.

In the present specification, the average particle diameter is measured by a particle size analyzer using a dynamic light scattering method. Pure water is added to the emulsion to dilute it 100 times, Nanotrac UPA-EX15
The 50% number average particle diameter measured using 0 (Nikkiso Co., Ltd.) is defined as the average particle diameter.

Examples of commercially available water-based emulsions include Pateracol RSI-001 (trade name, manufactured by DIC, water-based emulsion of urethane resin, resin content 30 to 40%), Pateracol RSI.
-401 (trade name, manufactured by DIC, water-based emulsion of acrylic resin, resin content 30 to 40%).

When the thermoplastic resin is obtained in an emulsion state, it can be prepared by mixing the resin particles with water. For example, an emulsion of (meth) acrylic resin or styrene- (meth) acrylic resin is composed of (meth) acrylic ester resin or styrene- (meth) acrylic ester resin and optionally (meth) acrylic resin. And are mixed with water.

An emulsion of a thermoplastic resin can also be obtained by emulsion polymerization of a resin monomer in water containing a polymerization catalyst and an emulsifier. The polymerization initiator, the emulsifier, and the molecular weight modifier used in the emulsion polymerization can be used according to a conventionally known method.

As the polymerization initiator, the same one used for normal radical polymerization is used,
For example, potassium persulfate, ammonium persulfate, hydrogen peroxide, azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, peracetic acid, cumene hydroperoxide, t-butyl hydroxyperoxide, and paramentane hydroxyperoxide Can be mentioned. When the polymerization reaction is performed in water, a water-soluble polymerization initiator is preferable. As an emulsifier, what is generally used as an anionic surfactant, a nonionic surfactant, an amphoteric surfactant other than sodium lauryl sulfate, and a mixture thereof are mentioned, for example. These may be used alone or in combination of two or more.

The thermoplastic resin may be mixed as a particle powder with other components in the anchor agent,
The resin particles are preferably dispersed in an aqueous medium to form a resin emulsion, and then mixed with other components of the anchor agent. In order to improve the long-term storage stability of the anchor agent, the average particle diameter of the resin particles is preferably in the range of 5 to 400 nm.

The resin is 20 to 50 in terms of solid content with respect to the total mass (100% by mass) of the anchor agent.
It is preferably contained in the range of mass%. If the amount of resin is too small, the anchor agent coating (undercoat layer) formed on the surface of the recording medium becomes thin, and the curability and line width may be inferior. If there are too many of these resins, the dispersion of the resin may become unstable during storage of the anchor agent, or the resin may agglomerate and solidify due to evaporation of a slight amount of water, making it impossible to form a uniform coating (undercoat layer). is there.

[Ink adhesion process]
In the ink adhering step, a predetermined ultraviolet curable ink jet ink is ejected from the ink jet head, and is adhered to the undercoat layer side of the recording medium provided with the undercoat layer. As a result, a colored layer (image) pattern is formed on the recording medium. An ink jet recording apparatus can be used as an apparatus for performing this step. Specific examples of the ink jet recording apparatus include, but are not limited to, PX-G5000 (ink jet printer,
Seiko Epson Corporation).

As a condition at the time of ink ejection in this step, the recording resolution can be in the range of 360 to 720 dpi. Droplet weight can range from 1 to 10 ng / pixel. Also,
It is preferable that the duty is in the range of 10% or less (the implantation amount is in the range of 0.7 mg / inch ² or less). It should be noted that shading occurs as image quality reproduction.
Can take a value close to 0%, so the lower limit of the duty (the amount of implantation) is not particularly limited.

Further, when the ink is discharged, the viscosity of the ink at 20 ° C. is preferably 15 mPa · s.
Hereinafter, it is more preferable to set it as 8-12 mPa * s. If the viscosity of the ink at 20 ° C. is within the above range, ejection failure can be prevented even if the ink is ejected at room temperature or without heating the ink.

Since the ultraviolet curable ink in the present embodiment has a higher viscosity than the water-based ink used in a normal inkjet recording ink, the viscosity variation due to temperature variation during ejection is large. Such fluctuations in the viscosity of the ink have a great influence on the change in the droplet size and the change in the droplet discharge speed, which can cause image quality deterioration. Therefore, it is preferable to keep the temperature of the ink during ejection as constant as possible.
The ultraviolet curable ink jet ink will be described later.

[Curing process]
The ink jet recording method of the present embodiment preferably further includes a curing step of irradiating the ink ejected and adhered in the ink adhesion step with ultraviolet rays to cure the ink.
In this way, a coating film (cured film) is formed by the ink cured on the recording medium.

In the curing step, the ink ejected on the recording medium is cured by irradiation with ultraviolet rays (light). This is because the photopolymerization initiator contained in the ink is decomposed by irradiation with ultraviolet rays to generate starting species such as radicals, acids, and bases, and the polymerization reaction of the polymerizable compound is accelerated by the function of the starting species. Because. Or it is because the polymerization reaction of a polymeric compound starts by irradiation of an ultraviolet-ray. At this time, if the sensitizing dye is present together with the photopolymerization initiator in the ink, the sensitizing dye in the system absorbs ultraviolet rays to be in an excited state, and promotes decomposition of the photopolymerization initiator by contacting with the photopolymerization initiator. And a more sensitive curing reaction can be achieved.

As an ultraviolet ray source, a mercury lamp, a gas / solid laser, or the like is mainly used, and as a light source used for curing an ultraviolet curable inkjet ink, a mercury lamp or a metal halide lamp is widely known. On the other hand, there is a strong demand for mercury-free from the viewpoint of environmental protection, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, an ultraviolet light emitting diode (UV-LED) and an ultraviolet laser diode (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as light sources for ultraviolet curable ink jets. Among these, UV-LED is preferable.

Here, it is preferable to use an ultraviolet curable inkjet ink that can be cured by irradiating ultraviolet rays having an emission peak wavelength of preferably in the range of 360 to 420 nm. In this case, curing at low energy and high speed is possible due to the composition of the ink in the present embodiment.
In the above case, the irradiation energy is preferably 300 mJ / cm ² or less, and 150 to ²
50 mJ / cm ² is more preferable. The irradiation energy is calculated by multiplying the irradiation time by the irradiation intensity.

Irradiation time can be shortened by the composition of the ink in this embodiment, in that case,
Increases printing speed. On the other hand, the irradiation intensity can also be reduced by the composition of the ink in the present embodiment, in which case the apparatus can be downsized and the cost can be reduced. In this case, UV-LED is preferably used for ultraviolet irradiation. Such an ink can be obtained by including at least one of a photopolymerization initiator that decomposes upon irradiation with ultraviolet rays in the wavelength range and a polymerizable compound that starts polymerization upon irradiation with ultraviolet rays in the wavelength range. The emission peak wavelength may be one or plural within the above wavelength range. Even in the case where there are a plurality, the total irradiation energy of the ultraviolet rays having the emission peak wavelength is set as the irradiation energy.

Next, the ultraviolet curable ink jet ink according to this embodiment will be described in detail.

[UV curable inkjet ink]
The ultraviolet curable ink jet ink used in the ink jet recording method of the present embodiment has the following general formula (I):
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. Group.)
(Hereinafter referred to as “monomer A”).

Hereinafter, additives (components) that are contained in the ultraviolet curable ink-jet ink (hereinafter, also simply referred to as “ink”) in this embodiment, or that can be optionally contained, will be described.

(Polymerizable compound)
The polymerizable compound contained in the ink can be polymerized at the time of light irradiation by the action of a photopolymerization initiator described later, and the printed ink can be cured.

(Monomer A)
In this embodiment, the monomer A, which is an essential polymerizable compound, contains a vinyl group and (
A compound having both a (meth) acrylic group and represented by the above general formula (I). This monomer A can be rephrased as vinyl ether group-containing (meth) acrylic acid esters.

When the ink contains the monomer A, the curability of the ink can be improved.

In the above general formula (I), the divalent organic residue represented by R ^{2 has 2} to 2 carbon atoms.
A linear, branched or cyclic alkylene group of 0, an alkylene group having 2 to 20 carbon atoms having an oxygen atom by at least one of an ether bond and an ester bond in the structure, and a carbon number of 6 to 11
Are preferably substituted divalent aromatic groups. Among these, ethylene group, n
-Oxygen due to an ether bond in a structure such as an alkylene group having 2 to 6 carbon atoms such as propylene group, isopropylene group and butylene group, oxyethylene group, oxy n-propylene group, oxyisopropylene group and oxybutylene group An alkylene group having 2 to 9 carbon atoms having an atom is preferably used.

In said general formula (I), as a C1-C11 monovalent organic residue represented by R < ³ >, a C1-C10 linear, branched or cyclic alkyl group, carbon An optionally substituted aromatic group of formula 6 to 11 is preferred. Among these, C6-C2 aromatic groups, such as a C1-C2 alkyl group which is a methyl group or an ethyl group, a phenyl group, and a benzyl group, are used suitably.

When the above organic residue is an optionally substituted group, the substituent is divided into a group containing a carbon atom and a group not containing a carbon atom. First, when the substituent is a group containing a carbon atom, the carbon atom is counted in the carbon number of the organic residue. Examples of the group containing a carbon atom include, but are not limited to, a carboxyl group and an alkoxy group. Next, examples of the group not containing a carbon atom include, but are not limited to, a hydroxyl group and a halo group.

Specific examples of the monomer A represented by the general formula (I) are not limited to the following,
(Meth) acrylic acid 2-vinyloxyethyl, (meth) acrylic acid 3-vinyloxypropyl, (meth) acrylic acid 1-methyl-2-vinyloxyethyl, (meth) acrylic acid 2-vinyloxypropyl, (meth) acrylic acid 4 -Vinyloxybutyl, 1-methyl-3-vinyloxypropyl (meth) acrylate, 1-vinyloxymethylpropyl (meth) acrylate, (
2-methyl-3-vinyloxypropyl (meth) acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth) acrylate, 3-vinyloxybutyl (meth) acrylate, 1-methyl-2-vinyl (meth) acrylate Roxypropyl, 2-vinyloxybutyl (meth) acrylate, 4-vinyloxycyclohexyl (meth) acrylate, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate, (meth) 3-vinyloxymethylcyclohexylmethyl acrylate, 2-vinyloxymethylcyclohexylmethyl (meth) acrylate, p-vinyloxymethylphenylmethyl (meth) acrylate, m-vinyloxymethylphenylmethyl (meth) acrylate, ( (Meth) acrylic acid o-vinyloxymethylpheny Methyl, (meth) acrylic acid 2- (vinyloxy ethoxy)
Ethyl, 2- (vinyloxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxy) propyl (meth) acrylate, 2- (vinyloxyethoxy) isopropyl (meth) acrylate, (meth) acrylic acid 2- (vinyloxyisopropoxy) propyl, (
2- (vinyloxyisopropoxy) isopropyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyisopropoxy) ethyl (meth) acrylate, (meth) acrylic acid 2- (vinyloxyisopropoxyethoxy) ethyl, 2- (vinyloxyisopropoxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) propyl (meth) acrylate, 2- (meth) acrylic acid 2- (Vinyloxyethoxyisopropoxy) propyl, (meth) acrylic acid 2- (
Vinyloxyisopropoxyethoxy) propyl, (meth) acrylic acid 2- (vinyloxyisopropoxyisopropoxy) propyl, (meth) acrylic acid 2- (vinyloxyethoxyethoxy) isopropyl, (meth) acrylic acid 2- (vinyloxy) Ethoxyisopropoxy) isopropyl, 2- (vinyloxyisopropoxyethoxy) isopropyl (meth) acrylate, 2- (vinyloxyisopropoxyisopropoxy) isopropyl (meth) acrylate, 2- (vinyloxyethoxy) (meth) acrylate Ethoxyethoxy) ethyl, (meth) acrylic acid 2- (vinyloxyethoxyethoxyethoxyethoxy) ethyl, (meth) acrylic acid 2- (isopropenoxyethoxy) ethyl, (meth) acrylic acid 2- (isopropenoxyethoxyethoxy) ) Chill, 2- (isopropenoxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxyethoxyethoxyethoxy) ethyl (meth) acrylate, polyethylene glycol monovinyl ether (meth) acrylate, and (meth) ) Acrylic acid polypropylene glycol monovinyl ether.

Among those described above, 2-vinyloxyethyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, 1-methyl-2-vinyloxyethyl (meth) acrylate, (
(Meth) acrylic acid 2-vinyloxypropyl, (meth) acrylic acid 4-vinyloxybutyl,
(Meth) acrylic acid 4-vinyloxycyclohexyl, (meth) acrylic acid 5-vinyloxypentyl, (meth) acrylic acid 6-vinyloxyhexyl, (meth) acrylic acid 4-vinyloxymethylcyclohexylmethyl, (meth) acrylic Acid p-vinyloxymethylphenylmethyl, 2- (vinyloxyethoxy) ethyl (meth) acrylate, 2- (meth) acrylic acid 2-
(Vinyloxyethoxyethoxy) ethyl and 2- (vinyloxyethoxyethoxyethoxy) ethyl (meth) acrylate are preferred.

Of these, 2- (vinyloxyethoxy) ethyl (meth) acrylate is preferred because of its low viscosity, high flash point, and excellent curability, and it also has low odor and suppresses irritation to the skin. In addition, 2- (vinyloxyethoxy) ethyl acrylate is more preferable because it is excellent in reactivity and adhesion.

Examples of 2- (vinyloxyethoxy) ethyl (meth) acrylate include 2- (2-vinyloxyethoxy) ethyl (meth) acrylate and 2- (1-vinyloxyethoxy) ethyl (meth) acrylate. Examples of 2- (vinyloxyethoxy) ethyl acrylate include 2- (2-vinyloxyethoxy) ethyl acrylate and 2- (1-vinyloxyethoxy) ethyl acrylate.

  Monomer A may be used individually by 1 type, and may be used in combination of 2 or more type.

Monomer A, especially 2- (vinyloxyethoxy) ethyl acrylate, is preferably contained in an amount of 10 to 87% by mass, more preferably 50%, based on the total mass (100% by mass) of the ink.
-80 mass% is contained. When the content is in the above range, the ink can be particularly excellent in terms of viscosity reduction and curability, and the curability can be further improved.

The production method of the monomer A represented by the general formula (I) is not limited to the following,
A method of esterifying (meth) acrylic acid and a hydroxyl group-containing vinyl ether (production method B),
Method of esterifying (meth) acrylic acid halide and hydroxyl group-containing vinyl ethers (Production method C), Method of esterifying (meth) acrylic anhydride and hydroxyl group-containing vinyl ethers (Production method D), (Meth) acrylic Method of transesterifying acid ester with hydroxyl group-containing vinyl ether (Production method E), Method of esterifying (meth) acrylic acid and halogen-containing vinyl ether (Production method F), Alkali (meth) acrylate (earth) Method of esterifying metal salt and halogen-containing vinyl ether (production method G), method of exchanging hydroxyl-containing (meth) acrylic acid esters with vinyl carboxylate (production method H), hydroxyl-containing (meth) acrylic acid ester And a method of exchanging ethers with alkyl vinyl ethers (Production Method I).

Among these, since the desired effect can be further exhibited in this embodiment, the production method E is preferable.

(Polymerizable compounds other than the above)
As the polymerizable compound other than the above (hereinafter, referred to as “other polymerizable compound”), conventionally known various monomers and oligomers such as monofunctional, bifunctional, and trifunctional or more polyfunctional can be used. . Examples of the monomer include unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid, and salts or esters thereof, urethane, amide and anhydride thereof, acrylonitrile, styrene. , Various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes. Examples of the oligomer include oligomers formed from the above monomers such as linear acrylic oligomers, epoxy (meth) acrylates, oxetanes (
Examples include (meth) acrylates, aliphatic urethane (meth) acrylates, aromatic urethane (meth) acrylates, and polyester (meth) acrylates.

Moreover, an N-vinyl compound may be included as another monofunctional monomer or polyfunctional monomer. Examples of such N-vinyl compounds include N-vinylcaprolactam, N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone, and acryloylmorpholine, and derivatives thereof.

Among other polymerizable compounds, an ester of (meth) acrylic acid, that is, (meth) acrylate is preferable, polyfunctional (meth) acrylate having 2 or more functions is more preferable, and polyfunctional acrylate is more preferable. In particular, the ink according to the present embodiment includes, as the polymerizable compound, at least one of the predetermined amount of monomer A, a polymerizable compound having an alicyclic structure in the molecule, and a polymerizable compound having a cyclic ether structure in the molecule. In addition, the adhesiveness is further improved by including a polyfunctional acrylate.

Among the above (meth) acrylates, monofunctional (meth) acrylates include, for example, isoamyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, iso Myristyl (meth) acrylate, isostearyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2-hydroxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydiethylene glycol ( (Meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate DOO, 2-hydroxyethyl (meth) acrylate, 2-
Hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (
And lactone-modified flexible (meth) acrylates. Among these, phenoxyethyl (meth) acrylate is preferable. When the ink composition contains phenoxyethyl (meth) acrylate, the content in the ink composition is preferably 5 to 50% by mass, and more preferably 10 to 45% by mass. Phenoxyethyl (
When the content of the (meth) acrylate is within the above range, the solubility of the photopolymerization initiator and the like can be further improved.

Among the above (meth) acrylates, as the polyfunctional (meth) acrylate, for example, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di ( (Meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonane Diol di (
(Meth) acrylate, neopentyl glycol di (meth) acrylate, di (meth) acrylate of bisphenol A, neopentyl glycol di (meth) hydroxypivalate
Bifunctional (such as acrylate and polytetramethylene glycol di (meth) acrylate)
(Meth) acrylate, and trimethylolpropane tri (meth) acrylate, glycerin propoxytri (meth) acrylate, cowprolactone-modified trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, sorbitol penta (meth) (Meth) acrylates having a pentaerythritol skeleton such as acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and pentaerythritol ethoxytetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactam modified Dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (
(Meth) acrylate, (meth) acrylate having a dipentaerythritol skeleton such as caprolactone-modified dipentaerythritol hexa (meth) acrylate, propionic acid-modified tripentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tri Pentaerythritol hepta (meth) acrylate, (pentaerythritol octa (meth) acrylate) and other (meth) acrylates having a tripentaerythritol skeleton, tetrapentaerythritol penta (meth) acrylate, tetrapentaerythritol hexa (meth) acrylate, tetrapenta Erythritol hepta (meth) acrylate, tetrapentaerythritol octa (meth)
Acrylate, tetrapentaerythritol nona (meth) acrylate, tetrapentaerythritol nona (meth) acrylate, and tetrapentaerythritol deca (meth)
(Meth) acrylate having tetrapentaerythritol skeleton such as acrylate, (meth) acrylate having pentapentaerythritol skeleton such as pentapentaerythritol undeca (meth) acrylate and pentapentaerythritol dodeca (meth) acrylate, and ethylene oxide thereof A trifunctional or higher functional (meth) acrylate such as at least one of (EO) adduct and propylene oxide (PO) adduct may be mentioned.

Among these, it is preferable that another polymeric compound contains polyfunctional (meth) acrylate as above-mentioned. Among the polyfunctional (meth) acrylates, the polyfunctional (meth) acrylate having the pentaerythritol skeleton is preferable, dipentaerythritol hexa (meth) acrylate is more preferable, and dipentaerythritol hexaacrylate is more preferable. In the above case, the viscosity of the ink is further lowered and the curability is further improved.

  The said other polymeric compound may be used individually by 1 type, and may use 2 or more types together.

The other polymerizable compound may be contained in an amount of 5 to 40% by mass with respect to the total mass (100% by mass) of the ink.

[Polymerization inhibitor]
The ink in this embodiment may contain a polymerization inhibitor. Examples of the polymerization inhibitor include, but are not limited to, p-methoxyphenol, cresol, t-butylcatechol, di-t-butylparacresol, hydroquinone monomethyl ether, α-naphthol,
3,5-di-tert-butyl-4-hydroxytoluene, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-butylphenol), and Phenol compounds such as 4,4′-thiobis (3-methyl-6-tert-butylphenol), p-benzoquinone, anthraquinone, naphthoquinone, phenanthraquinone, p-xyloquinone, p-toluquinone, 2,6-dichloroquinone, 2,5-diphenyl-p-benzoquinone, 2,5-diacetoxy-p-benzoquinone, 2,5-dicaproxy-p-benzoquinone, 2,5-diacyloxy-p-benzoquinone, hydroquinone, 2,5
-Dibutylhydroquinone, mono-t-butylhydroquinone, monomethylhydroquinone,
And quinone compounds such as 2,5-di-t-amylhydroquinone, phenyl-β-naphthylamine, p-benzylaminophenol, di-β-naphthylparaphenylenediamine, dibenzylhydroxylamine, phenylhydroxylamine, and diethylhydroxylamine Amine compounds such as dinitrobenzene, trinitrotoluene, and picric acid, oxime compounds such as quinonedioxime and cyclohexanone oxime, and sulfur compounds such as phenothiazine.

(Photopolymerization initiator)
The ink in this embodiment preferably contains a photopolymerization initiator. By using a photopolymerizable compound as the above-described polymerizable compound, it is possible to omit the addition of a photopolymerization initiator. However, it is preferable to use a photopolymerization initiator because the start of polymerization can be easily adjusted.

The photopolymerization initiator is used to form an image by curing ink present on the surface of a recording medium by photopolymerization by irradiation with ultraviolet rays. The photopolymerization initiator is not limited as long as it generates active species such as radicals and cations by the energy of light and initiates the polymerization of the polymerizable compound. A polymerization initiator can be used, and among these, it is preferable to use a radical photopolymerization initiator.

Examples of the photo radical polymerization initiator include aromatic ketones, acyl phosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiphenyls, and the like. Examples include imidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

Among these, since the curability of the ink can be particularly improved, at least one of the acylphosphine oxide compound and the thioxanthone compound is preferable,
An acyl phosphine oxide compound and a thioxanthone compound are more preferable.

Specific examples of the photo radical polymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine. , Carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) ) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthio Xanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenyl Phosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone, and bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide Can be mentioned.

Examples of commercially available radical photopolymerization initiators include IRGACURE 651 (2, 2
-Dimethoxy-1,2-diphenylethane-1-one), IRGACURE 184 (1
-Hydroxy-cyclohexyl-phenyl-ketone), DAROCUR 1173 (2-
Hydroxy-2-methyl-1-phenyl-propan-1-one), IRGACURE 2
959 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one), IRGACURE 127 (2-hydroxy-1- {
4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl] -2
-Methyl-propan-1-one}, IRGACURE 907 (2-methyl-1- (4-
Methylthiophenyl) -2-morpholinopropan-1-one), IRGACURE 3
69 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1), IRGACURE 379 (2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone), DA
ROCUR TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), IRGACURE 819 (bis (2,4,6-trimethylbenzoyl)-
Phenylphosphine oxide), IRGACURE 784 (bis (η5-2,4-
Cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole)
1-yl) -phenyl) titanium), IRGACURE OXE 01 (1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]), I
RGAURE OXE 02 (ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime)), IRG
ACURE 754 (mixture of oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) ethyl ester) (above, manufactured by BASF), Speedcure TPO (Lambso
n), KAYACURE DETX-S (2,4-diethylthioxanthone) (manufactured by Nippon Kayaku Co., Ltd.), Lucirin TPO, LR8883, L
R8970 (above, manufactured by BASF), Ubekrill P36 (manufactured by UCB), and the like.

The said photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type.

The photopolymerization initiator sufficiently exhibits the ultraviolet curing rate, and avoids undissolved photopolymerization initiator and coloring derived from the photopolymerization initiator, so that the total mass (100% by mass) of the ink composition is used. 5 to 20% by mass is preferable.

[Color material]
The ink in the present embodiment preferably further includes a color material. As the color material, at least one of a pigment and a dye can be used.

(Pigment)
In the present embodiment, by using a pigment as the color material, the light resistance of the ink can be improved. As the pigment, both inorganic pigments and organic pigments can be used.

As the inorganic pigment, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, iron oxide, and titanium oxide can be used. In addition, as a commercial item of titanium oxide, for example, CR60
-2 (trade name made by ISHIHARA SANGYO KAISHA, LTD.).

Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc. Polycyclic pigments, dye chelates (eg basic dye chelates, acid dye chelates, etc.), dye rakes (basic dye rakes, acid dye rakes), nitro pigments, nitroso pigments, aniline black, daylight A fluorescent pigment is mentioned.

More specifically, as carbon black used as black ink, No. 23
00, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52,
MA7, MA8, MA100, No. 2200B, etc. (above, Mitsubishi Chemical Corporation (Mitsubishi Che
mical Corporation), Raven 5750, Raven 5250, Raven
5000, Raven 3500, Raven 1255, Raven 700, etc. (above, Columbia Carbon), Rega1 400R, Rega
1 330R, Rega1 660R, Mogul L, Monarch 700, Mo
narch 800, Monarch 880, Monarch 900, Monarc
h 1000, Monarch 1100, Monarch 1300, Monarch
1400 etc. (manufactured by CABOT JAPAN K.K.), Color Black F
W1, Color Black FW2, Color Black FW2V, Colo
r Black FW18, Color Black FW200, Color B1a
ck S150, Color Black S160, Color Black S17
0, Printex 35, Printex U, Printex V, Printex
140U, Special Black 6, Special Black 5, Sp
special Black 4A, Special Black 4 (Degussa (De
gussa)).

Examples of pigments used in white ink include C.I. I. Pigment White 6, 18,
21.

Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3
4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 3
7, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98
99, 108, 109, 110, 113, 114, 117, 120, 124, 128,
129, 133, 138, 139, 147, 151, 153, 154, 167, 172,
180.

Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 2
1, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 4
8 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144
146, 149, 150, 166, 168, 170, 171, 175, 176, 177
178, 179, 184, 185, 187, 202, 209, 219, 224, 245
Or C.I. I. Pigment Violet 19, 23, 32, 33, 36, 38, 43
, 50.

Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 1
5, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25,
60, 65, 66, C.I. I. Bat Blue 4, 60.

Examples of pigments other than magenta, cyan, and yellow include C.I. I. Pigment green 7,10, C.I. I. Pigment brown 3, 5, 25, 26, C.I. I.
Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 3
8, 40, 43, 63.

  The said pigment may be used individually by 1 type, and may use 2 or more types together.

When the above pigment is used, the average particle size is preferably 300 nm or less, and 50 to 25
0 nm is more preferable. When the average particle diameter is in the above range, the ink can be more excellent in reliability such as ejection stability and dispersion stability, and an image with excellent image quality can be formed. Here, the average particle diameter in this specification is measured by the above-mentioned dynamic light scattering method.

(dye)
In the present embodiment, a dye can be used as the color material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79,
142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I
. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94
, C.I. I. Food Black 1, 2, C.I. I. Direct yellow 1, 12, 24, 3
3, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct blue 1, 2,
15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35
Is mentioned.

  The said dye may be used individually by 1 type, and may use 2 or more types together.

The content of the color material is preferably in the range of 1 to 20% by mass with respect to the total mass (100% by mass) of the ink.

[Dispersant]
When the ink in this embodiment contains a pigment, it may further contain a dispersant in order to improve pigment dispersibility. Although it does not specifically limit as a dispersing agent, For example, the dispersing agent currently used in preparing pigment dispersions, such as a polymer dispersing agent, is mentioned. Specific examples include polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, sulfur-containing polymers, fluorine-containing polymers, and epoxies. The thing which has 1 or more types of resin as a main component is mentioned. Commercially available polymer dispersants include Ajinomoto Fine Techno's Ajisper series, LUBRIZOL's Solsper's series (Solsperse 36000, etc.), BYK's Dispervic series, and Enomoto Kasei's Disparon series. It is done.

[Slip agent]
The ink in this embodiment may further contain a slip agent (surfactant). The slip agent is not particularly limited. For example, polyester-modified silicone or polyether-modified silicone can be used as a silicone-based surfactant, and polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane is particularly used. preferable. Specific examples include BYK-347, BYK-348, BYK-UV35.
00, 3510, 3530, 3570 (manufactured by BYK).

[Other additives]
The ink in the present embodiment may include additives (components) other than the additives listed above. Such components are not particularly limited, and may include, for example, conventionally known polymerization accelerators, penetration enhancers, wetting agents (humectants), and other additives. Examples of the other additives include conventionally known fixing agents, antifungal agents, preservatives, antioxidants, ultraviolet absorbers,
Chelating agents, pH adjusters, and thickeners can be mentioned.

As described above, according to this embodiment, an ink jet recording method excellent in all of the tackiness of the ink receiving layer (undercoat layer), the viscosity of the ink, the curability of the ink, and the line width upon printing is provided. be able to. Furthermore, the ink jet recording method of the present embodiment controls the ink penetration speed into the recording medium by smoothing the recording medium with an undercoat layer interposed therebetween, or the affinity of the ink for the recording medium. The contact angle is controlled by suppressing (wetting) to some extent. Thus, bleeding (bleed) due to ink permeation caused by voids and fiber gaps in the recording medium such as YUPO paper and fine paper,
It is possible to suppress filling failure (a state in which the background color of the recording medium is visible) and curing failure.

Hereinafter, the embodiments of the present invention will be described more specifically by way of examples. However, the embodiments are not limited to these examples.

[Materials used]
The materials used in the following examples and comparative examples are as follows.
(Polymerizable compound)
2- (2-vinyloxyethoxy) ethyl acrylate (VEEA [trade name], trade name by Nippon Shokubai Co., Ltd., hereinafter abbreviated as “VEEA”)
Dipentaerythritol hexaacrylate (NK ester A-DPH [trade name], manufactured by Shin-Nakamura Chemical Co., Ltd., hereinafter abbreviated as “DPEHA”)
・ Biscoat # 192 (Phenoxyethyl acrylate, Osaka Organic Chemical Industry Co., Ltd. (OSAKA OR
GANIC CHEMICAL INDUSTRY LTD.) Product name, hereinafter abbreviated as “PEA”. )
2-methoxyethyl acrylate (2-MTA [trade name], manufactured by Osaka Organic Chemical Industry Co., Ltd., hereinafter abbreviated as “MOEA”)
Dipropylene glycol diacrylate (APG-100 [trade name], manufactured by Shin-Nakamura Chemical Co., Ltd., hereinafter abbreviated as “DPGDA”)
Tripropylene glycol diacrylate (APG-200 [trade name], manufactured by Shin-Nakamura Chemical Co., Ltd., hereinafter abbreviated as “TPGDA”)
N-vinylcaprolactam (manufactured by BASF, abbreviated as “NVC” in Table 1)
(Photopolymerization initiator)
IRGACURE 819 (trade name, manufactured by BASF, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, solid content 100%, hereinafter abbreviated as “819”)
DAROCURE TPO (trade name, manufactured by BASF, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, solid content 100%, hereinafter abbreviated as “TPO”.
)
KAYACURE DETX-S (Nippon Kayaku Co., Ltd. trade name, hereinafter abbreviated as “DETX-S”)
[Slip agent]
Silicone surface conditioner BYK-UV3500 (polydimethylsiloxane having a polyether-modified acrylic group, trade name by BYK, hereinafter abbreviated as “UV3500”)
[Polymerization inhibitor]
・ P-methoxyphenol (KANTO CHEMICAL CO., INC)
Abbreviated as “EHQ”. )
[Pigment]
・ IRGALITE BLUE GLVO (Color index name: Pigment Blue
15. Product name manufactured by BASF, abbreviated as “cyan” below. )
[Dispersant]
・ Solsperse 36000 (trade name, manufactured by LUBRIZOL, hereinafter “Sol 36000
". )
[Recording medium]
-YUPO (registered trademark) paper FGS80 (manufactured by Yupo Corporation, synthetic paper, surface roughness 1.446)
PET 50A (Lintec Corporation product name, PET transparent film,
Surface roughness 0.145)
PET50 (K2411) PAT1E (trade name, foamed PET film, surface roughness 1.112 manufactured by Lintec Corporation)

The surface roughness of each recording medium is determined by observing the surface of the recording medium using a laser microscope VK-9700 (trade name, manufactured by KEYENCE) and reading the root mean square height (Rq value) of the surface. Was measured.

[Examples 1 to 23]
[Preparation of UV curable inkjet ink]
The components described in Table 1 below were added so as to have the composition (unit: mass%) described in Table 1, and this was mixed and stirred at room temperature for 1 hour to be completely dissolved. This was further filtered through a 5 μm membrane filter to obtain ultraviolet curable inkjet inks having compositions 1 to 8.

[Preparation of anchor agent and formation of undercoat layer]
First, Pateracol RSI-001 (trade name, manufactured by DIC, water-based emulsion of urethane resin, resin content 30 to 40%), which is a commercial product, is referred to as “anchor agent 1” and Pateracol RSI.
-401 (trade name, manufactured by DIC, water-based emulsion of acrylic resin, resin content 30 to 40%) was designated “anchor agent 2”.

Next, cation-modified polyvinyl alcohol (PVA-C-318AA Kuraray Co., Ltd. (KURA
RAY CO., LTD), 10% by weight of cationic groups) and 90% by weight of ultrapure water were mixed to prepare an aqueous PVA solution (resin content 30%). did.

Anchor agent 1, anchor agent 2, and anchor agent 3 were applied on the recording media shown in Tables 3 and 4 below by a roll coater, and then dried at 100 ° C. for 2 minutes to form an undercoat layer. The thickness of the undercoat layer after drying is as shown in Table 3 and Table 4 below.

[Evaluation item]
About the ultraviolet curable inkjet ink prepared by each Example and the comparative example, tack property, a viscosity, adhesiveness, and shrinkage | contraction property were evaluated with the following method.

[Tackiness]
The surface of the undercoat layer obtained by drying each anchor agent as described above was rubbed with a Johnson swab manufactured by Johnson & Johnson. At this time, when the undercoat layer adhered to the cotton swab or the undercoat layer on the recording medium was scratched, it was determined that there was tack (poor tackiness). Note that the number of times of rubbing is 10 reciprocations and the rubbing strength is 1
The load was 00 g.
The evaluation criteria are as follows. The evaluation results are shown in Tables 3 and 4 below.
A: After drying the anchor agent, there was no tack on the surface of the undercoat layer.
B: There was tack on the surface of the undercoat layer after the anchor agent was dried.

[Ink viscosity]
The viscosity of each ink was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.)
Measurement was performed under conditions of a temperature of 20 ° C. and a rotation speed of 10 rpm. The evaluation results are shown in Tables 3 and 4 below.
AA: 10 mPa · s or less,
A: more than 10 mPa · s and not more than 15 mPa · s,
B: Over 15 mPa · s.

[Ink curing]
Inkjet printer PX-G5000 (Seiko Epson Co
rporation) and the above ultraviolet curable inkjet inks were filled into the respective nozzle rows. On each recording medium (Examples 1 to 14 are the undercoat layer side of the recording medium) at room temperature and normal pressure, a recording resolution of 720 dpi × 720 dpi, a droplet weight of 10 ng / pixel,
The image was printed under the conditions of Duty 10% (injection amount 0.52 mg / inch ² ).
Along with the above printing, from the UV-LED in the ultraviolet irradiation device mounted on the side of the carriage,
The solid pattern image was cured by irradiation with ultraviolet rays having an irradiation intensity of 400 mW / cm ² and a wavelength of 395 nm. In addition, it was judged that it was hardened | cured when the tackiness of the image (coating film surface) disappeared by the finger touch test.
Evaluation was performed by calculating the irradiation energy of ultraviolet rays required for curing. The irradiation energy [mJ / cm ² ] is the irradiation intensity [mW on the irradiated surface irradiated from the light source.
/ Cm ² ] was measured and obtained from the product of this and the irradiation duration [s]. The measurement of irradiation intensity
UV intensity meter UM-10, light receiving unit UM-400 (both Konica Minolta Sensing (
KONICA MINOLTA SENSING, INC.)).
The evaluation criteria are as follows. A and B are practically acceptable evaluation criteria. The evaluation results are shown in Tables 3 and 4 below.
A: 200 mJ / cm ² or less,
B: More than 200 mJ / cm ^{2 and} 300 mJ / cm ² or less,
C: more than 300 mJ / cm ^{2 and} 400 mJ / cm ² or less,
D: Over 400 mJ / cm ² .

[Line width]
The maximum value of the line width when one line of the prepared ultraviolet curable ink-jet ink was discharged at a resolution of 720 dpi and an ink weight of 10 ng / pixel was measured, and this was taken as the line width.
The line width evaluation criteria were set in consideration of the following burial evaluation and bleed evaluation.
For the evaluation of filling, a test pattern was printed under the conditions of a recording resolution of 720 dpi × 720 dpi, a droplet weight of 10 ng / pixel, and a duty of 100%. ○ is a practically acceptable evaluation standard.
X: The background color of the recording medium was visible.
○: The background color of the recording medium was not visible.
For the bleed evaluation, the same test pattern as the filling evaluation was printed. ○ and Δ are practically acceptable evaluation criteria.
X: Ink bleeding was observed around the pattern by visual inspection.
(Triangle | delta): Although the blur was not seen visually around the pattern, the blur was seen by observation with a microscope.
○: No bleeding was observed with a microscope.

  The correspondence between the evaluation criteria for line width, filling, and bleed is as shown in Table 2 below.

From Table 2 above, AA, A, and B-1 are practically acceptable evaluation criteria. The evaluation results are shown in Tables 3 and 4 below.

From Tables 3 and 4 above, compositions 1 to 5 containing VEEA are inherently excellent in curability, but when recording on a recording medium having a large surface roughness, the ink spreads and is subjected to oxygen inhibition, so that the curability is improved. Presumed to be inferior. When an anchor agent is applied and ink spreading is suppressed, good curability can be obtained. It has been found that when an anchor agent is used in compositions 6 to 8 not containing VEEA, the effect of suppressing the spread is the same, but the curability is inferior, and the curability cannot be improved even if the spread is suppressed. In addition, although it was possible to describe the characters on the surface of the recording medium YUPO, K2411 with a pencil (Mitsubishi Pencil Co., Ltd., Uni HB), it was not possible to describe the characters on PET 50A. Use the non-ink adhesion area of the recording medium).

Further, from Examples 1 and 9 and Examples 15 and 20, a recording medium having a surface roughness of less than 1 (
When PET 50A) is used, the evaluation results are the same regardless of the presence or absence of the anchor agent, whereas when a recording medium (YUPO) having a surface roughness of 1 or more is used, the ink is obtained by using the anchor agent. It was found that the curability and the line width were significantly superior.

Although not shown in the above results, when ink jet recording was performed in a system in which the thickness of the undercoat layer (anchor agent) exceeded 20 μm, the drying time after application was 30 minutes or more, and the efficiency was slightly poor. It was confirmed.

Claims (9)

An undercoat layer is formed on a recording medium having an Rq value (square root height) having a surface roughness of 1 to 1.446 μm and containing a resin as a dispersion liquid and the dispersion medium is water or an organic solvent. Providing, and
On the undercoat layer side of the recording medium provided with the undercoat layer, the following general formula (I):
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. Group.)
Adhering an ultraviolet curable inkjet ink containing 10 to 87% by mass of the compound represented by the following formula to the recording medium:
The inkjet recording method wherein the thickness of the undercoat layer after drying is 5 to 20 μm.   The inkjet recording method according to claim 1, wherein the resin is at least one of an acrylic resin and a urethane resin. The inkjet recording method according to claim 1, wherein the step of providing the undercoat layer includes providing an undercoat layer using an aqueous dispersion of the resin. Wherein the step of providing an undercoat layer, the resin comprising applying at least one aqueous dispersion of the acrylic resin及beauty urethane resins, ink jet recording method according to claim 2. Wherein said ultraviolet curable ink ink 0.7 mg / inch ² following conditions is deposited on the recording medium, ink jet recording method according to any one of claims 1-4. The said ultraviolet curable ink for inkjet contains 10-80 mass% 2- (vinyloxyethoxy) ethyl acrylate with respect to the gross mass of this ink, The any one of Claims 1-5 . Inkjet recording method. The viscosity at 20 ° C. UV-curable inkjet ink is not more than 15 mPa · s, ink-jet recording method according to any one of claims 1-6. The inkjet recording according to any one of claims 1 to 7 , wherein a recorded line width value is smaller than that in the case of performing recording in the same manner except that the step of providing the undercoat layer is not performed. Method. Claim 1 is intended for use in the ink jet recording method according to any one of 8, the liquid for the undercoat layer formed with the ultraviolet-curable inkjet ink.