JP6000208B2 - Inkjet recording method - Google Patents

Description

  The present invention relates to an inkjet recording method and a printed matter.

As an image recording method for forming an image on a recording medium such as paper based on an image data signal, there are an electrophotographic method, a sublimation type and a melt type thermal transfer method, an ink jet method and the like.
The ink jet method is an inexpensive printing apparatus and does not require a plate at the time of printing, and the ink composition is ejected only on the required image portion to form an image directly on a recording medium. It can be used efficiently, and the running cost is low especially for small lot production. Furthermore, it has low noise and is excellent as an image recording method, and has attracted attention in recent years.
In particular, an ink composition for ink jet recording (a radiation curable ink composition for ink jet recording) that can be cured by irradiation with radiation such as ultraviolet rays is cured by irradiation with radiation such as ultraviolet rays, and most of the components of the ink composition are cured. It is an excellent method in that it can be printed on various recording media because it is excellent in drying property and difficult to bleed out as compared with the solvent-based ink composition.

Until now, soft packaging printing has been performed mainly by conventional printing methods such as gravure printing and flexographic printing. However, in recent years, digital printing capable of responding to the increase in small lot printing has also attracted attention in the flexible packaging field. In the case of digital printing, there is no need to create a plate and color matching is not required, so it is possible to reduce costs, especially when printing small lots, and to shorten the printing time because preparation time can be reduced. It also leads to.
Examples of conventional inkjet recording methods include the methods described in Patent Documents 1 to 3.

JP 2013-043894 A JP 2008-105377 A JP 2009-184206 A

  The problem to be solved by the present invention is to provide an ink jet recording method capable of obtaining a printed matter in which migration from a cured image is suppressed, ink bleeding and repellency is suppressed, and odor is low, and a printed matter. .

The above-mentioned problems of the present invention have been solved by means described in the following <1> and <12>. It is described below together with <2> to <11> which are preferred embodiments.
<1> (Step a) A step of preparing a recording medium having an undercoat layer (1) obtained by completely curing the undercoat composition (I), (Step b) applying the undercoat composition (II) on the undercoat layer (1). A step of irradiating the applied undercoat composition (II) with actinic rays and semi-curing, (Step c) discharging the ink composition (III) onto the semi-cured undercoat composition (II) And (step d) irradiating the undercoat composition (II) and the ink composition (III) with actinic rays to cure the whole, in this order, the undercoat composition (I) and the undercoat composition The product (II) and the ink composition (III) each contain (Component A) a radical polymerizable compound and (Component B) a polymerization initiator, and the undercoat composition (II) and the ink composition (III). ), 60% by mass of each composition with a polyfunctional ethylenically unsaturated compound as component A The ink jet recording method, wherein the undercoat composition (I) contains an acrylate oligomer as component A,
<2> The ink jet recording method according to <1>, wherein the undercoat composition (I) contains an acrylate oligomer in an amount of 60% by mass or more of the composition,
<3> When the surface tension of the undercoat composition (II) at 25 ° C. is P _II (mN / m) and the surface tension of the undercoat composition (I) at 25 ° C. is P _I (mN / m), the following formula The inkjet recording method according to <1> or <2>, which satisfies (X),
1 ≦ P _I −P _II ≦ 15 (X)

<4> When the amount of surfactant contained in the undercoat composition (II) is Q _II mass% and the amount of surfactant contained in the undercoat composition (I) is Q _I mass%, the following formula (Y) is obtained: The inkjet recording method according to any one of <1> to <3>,
1 <Q _II / Q _I ≦ 15 (Y)

<5> The inkjet recording method according to any one of <1> to <4>, wherein the step d is a step of irradiating active rays at an oxygen partial pressure of 0.15 atm or less.
<6> Any one of <1> to <5>, wherein the undercoat composition (I), the undercoat composition (II), and the ink composition (III) contain an acylphosphine oxide compound as Component B An inkjet recording method according to claim 1,
<7> The inkjet recording method according to any one of <1> to <6>, wherein the actinic rays in steps b and d are actinic rays irradiated by an LED,
<8> The inkjet recording method according to any one of <1> to <7>, wherein the undercoat composition (II) and the ink composition (III) contain an alkylene glycol diacrylate as the component A,
<9> The ink composition (III) according to any one of <1> to <8>, wherein the ink composition (III) contains a compound represented by the following formula (1) and / or formula (2) as the component B: Inkjet recording method,

(In Formula (1) and Formula (2), R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, and x and y are each independently Each represents an integer of 2 to 4, j and m each independently represents an integer of 0 to 4, k and n each independently represents an integer of 0 to 3, and j, k, m and n are When it is an integer of 2 or more, a plurality of R ¹ , R ² , R ³ and R ⁴ may be the same or different, and X ¹ includes at least ^one of a hydrocarbon chain, an ether bond and an ester bond x And X ² represents a y-valent linking group containing at least one of a hydrocarbon chain, an ether bond, and an ester bond.)

<10> The inkjet recording method according to any one of <1> to <9>, which is for package printing.
<11> The recording medium is a resin film having a film thickness of 10 μm or more and 90 μm or less and containing at least one component selected from the group consisting of polyethylene terephthalate, polyethylene, polypropylene, and nylon. <1> ~ inkjet recording how according to any one of <10>.

  ADVANTAGE OF THE INVENTION According to this invention, the migration from a cured image was suppressed, and the ink-jet recording method and printed matter which can obtain the printed matter with which the bleeding and repelling of ink were suppressed and there were few odors were able to be provided.

It is a schematic diagram which shows an example of the inkjet recording device used suitably for this invention. It is a schematic diagram which shows the image used for evaluation of a blur in an Example.

(Inkjet recording method)
The inkjet recording method of the present invention provides a recording medium having an undercoat layer (1) in which (Step a) the undercoat composition (I) (hereinafter also simply referred to as “composition (I)”) is completely cured. Step (Step b) An undercoat composition (II) (hereinafter, also simply referred to as “composition (II)”) is applied onto the undercoat layer (1), and active light is applied to the applied undercoat composition (II). (Step c) ink composition (III) (hereinafter referred to as “ink composition” or “composition (III)”) on the semi-cured undercoat composition (II) And (step d) a step of irradiating the undercoat composition (II) and the ink composition (III) with actinic rays to cure the whole (hereinafter referred to as “overall curing step”). In this order, the undercoat composition (I), the undercoat composition (II), and the The composition (III) contains (Component A) a radically polymerizable compound and (Component B) a polymerization initiator, and the undercoat composition (II) and the ink composition (III) are many as Component A. It contains 60% by mass or more of a functional ethylenically unsaturated compound, and the undercoat composition (I) contains an acrylate oligomer as component A.
The ink jet recording method of the present invention is suitable for package printing, and is particularly suitable for package printing for food packaging.

The present inventor has found that there is a problem that the substrate adhesion of the image is insufficient when an image is formed by a conventional ink jet recording method, particularly in food packaging package printing for soft packaging. The inventor has intensively studied and found that the adhesion is improved by forming an image using the composition (I) containing the acrylate oligomer, but the composition (I) is cured. When an ink composition was directly applied onto a material to form an image, a sufficient problem of bleeding occurred although sufficient substrate adhesion was obtained.
On the other hand, in order to improve the problem of bleeding, when the composition (I) is in a semi-cured state and an image is formed thereon with the ink composition, sufficient adhesion cannot be obtained.
The present inventor forms a semi-cured layer with the composition (II) on the cured product of the composition (I), and further forms an image with the ink composition on the layer, thereby providing adhesion to the substrate. The present invention has been completed by finding out that an image having excellent image quality and further suppression of bleeding can be obtained.
Further, the composition (II) and the composition (III) contain a polyfunctional ethylenically unsaturated compound of 60% by mass or more of the whole composition, so that a printed matter with less odor and suppressed migration can be obtained. I found.

In the specification, the description of “A to B” representing a numerical range is synonymous with “A or more and B or less”. Further, “(component A) radical polymerizable compound” or the like is also simply referred to as “component A” or the like. Further, “mass%” and “part by mass” are synonymous with “% by weight” and “part by weight”, respectively.
Furthermore, in the present invention, when referring to “acrylate” and / or “methacrylate”, “(meth) acrylate” and when referring to both “acryl” and “methacryl” or “(meth) acryl” May be described respectively.
In the following description, a combination of preferred embodiments is a more preferred embodiment.
Hereinafter, the present invention will be described in detail.

(Step a) Step of preparing a recording medium having an undercoat layer (1) in which the undercoat composition (I) is completely cured The ink jet recording method of the present invention comprises an undercoat layer in which the undercoat composition (I) is completely cured ( Including a step of preparing a recording medium having 1).
The undercoat composition (I) contains (Component A) a radical polymerizable compound and (Component B) a polymerization initiator, and contains an acrylate oligomer as Component A.
A preferred embodiment of the undercoat composition (I) in the present invention will be described later.

The recording medium (base material, support, recording material, etc.) used in the ink jet recording method of the present invention is not particularly limited, and any known recording medium can be used. Among these, a transparent recording medium is preferable.
In the present invention, “transparent” means that the visible light transmittance is 80% or more, and the visible light transmittance is preferably 90% or more. A transparent recording medium may be colored as long as it is transparent, but is preferably a colorless recording medium.
Specific examples of the recording medium include glass, quartz, plastic film (for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, acrylic resin, chlorinated polyolefin resin, poly Ether sulfone resin, polyethylene terephthalate (PET), polyethylene naphthalate, nylon, polyethylene, polystyrene, polypropylene, polycycloolefin resin, polyimide resin, polycarbonate resin, polyvinyl acetal, and the like.
The transparent recording medium may be a mixture of two or more of these resins, or a laminate of two or more of these resins.

Among them, the recording medium is preferably a recording medium having an image forming surface made of at least one resin selected from the group consisting of polyolefin resin, polyester resin and polyamide resin, and polyethylene terephthalate, polyethylene, polypropylene and nylon. More preferably, the recording medium has an image forming surface made of at least one resin selected from the group consisting of, and consists of at least one resin selected from the group consisting of polyethylene terephthalate, polyethylene, polypropylene and nylon. More preferably, it is a recording medium.
As polyethylene, LDPE (low density polyethylene), MDPE (medium density polyethylene), HDPE (high density polyethylene), and polypropylene as CPP (unstretched polypropylene), OPP (biaxially stretched polypropylene), KOP (polyvinylidene chloride coating) As the OPP), AOP (PVA-coated OPP), and polyethylene terephthalate, biaxially stretched polyester and nylon as the ON (stretched nylon), KON (stretched nylon), and CN (unstretched nylon) are preferably used.
In addition, EVA (ethylene / vinyl acetate copolymer film), PVA (vinylon), EVOH (polyvinyl alcohol), PVC (polyvinyl chloride), PVDC (polyvinylidene chloride, saran), cellophane (PT, MST, K cello), It is also preferable to use a combination with ZX (Zecron (polyacrylonitrile, PAN)) and PS (polystyrene, styrene).
An optimum material is selected depending on the application of the package, and a film having a combination of the characteristics of each material can be produced by forming a multilayer film.
Moreover, AL (aluminum foil), VM film (aluminum vapor-deposited film, transparent vapor-deposited film), etc. can be incorporated in the multilayer structure for the purpose of improving the strength of the package and blocking oxygen.
In recent years, a co-extruded film in which a resin is extruded from two or more parallel slits to form a film and laminate at the same time is also preferably used. Even films as thin as a few μm that cannot be made into a film can be laminated up to 5 to 7 layers, so films with various performances and applications have been made.

  Although there is no restriction | limiting in particular as thickness of the said recording medium, It is preferable that it is 1-500 micrometers, It is more preferable that it is 2-200 micrometers, It is further more preferable that it is 5-100 micrometers, It is 10-90 micrometers. Is particularly preferred.

In the present invention, the recording medium having the undercoat layer (1) obtained by completely curing the undercoat composition (I) may be prepared as a recording medium provided with the undercoat layer (1) in advance, The following step a ¹ and step a ² may be performed in this order together with step c.
(Step a ¹ ) A step of applying the undercoat composition (I) on the recording medium,
(Step a ² ) A step of irradiating the applied undercoat composition (I) with actinic rays to completely cure it to form an undercoat layer (1) (hereinafter also referred to as “complete curing step”).
In the present invention, when performing step b and step c, it is more preferable to perform step a ¹ and step a ² .

(Step a ¹ ) Step of applying undercoat composition (I) on recording medium In the ink jet recording method of the present invention, as means for applying the undercoat composition (I) on the recording medium, a coating device or an ink jet nozzle is used. It is preferable to use a coating apparatus.
There is no restriction | limiting in particular as said coating device, According to the objective etc., it can select suitably according to the objective etc., for example, an air doctor coater, a blade coater, a lot coater, a knife coater, a squeeze coater, an impregnation coater , Reverse roll coater, transfer roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater and extrusion coater. For details, see Yuji Harasaki's “Coating Engineering”.
Among these, from the viewpoint of apparatus cost, the application of the undercoat composition (I) onto the recording medium is preferably performed using a relatively inexpensive bar coater or spin coater.

The undercoating composition (I) is preferably applied to the same area as the image formed by ejecting ink droplets on the recording medium in step c or to an area wider than the image, and covers the entire area where the image can be formed. It is preferable to be provided so as to cover.
Basecoating composition applied amount (I) (mass per unit area) is preferably 0.05-5 g / m ^2, and more preferably 0.06~3g / m ^2. When the application amount of the undercoat composition (I) is within the above range, a sufficient adhesion improving effect can be obtained and a printed matter having excellent flexibility can be obtained.

(Step a ² ) A step of irradiating the applied undercoat composition (I) with actinic rays to completely cure it to form an undercoat layer (1) (complete curing step)
The method of causing an actinic ray to cause a complete curing reaction is a method in which the polymerization reaction of the ethylenically unsaturated compound contained in the undercoat composition (I) applied to the recording medium is sufficiently performed.
As the actinic rays, in addition to ultraviolet rays, for example, visible rays, α rays, γ rays, X rays, electron rays, and the like can be used. Among these, the active light is preferably ultraviolet light or visible light, and particularly preferably ultraviolet light, from the viewpoint of cost and safety.
The “complete cure” in the present invention means a state in which the inside and the surface of the composition on the recording medium are completely cured, and means that transfer is not recognized in the following transfer test. Specifically, after irradiation with actinic rays, plain paper (copy paper manufactured by Fuji Xerox Co., Ltd.) is applied to the undercoat layer (1) with a uniform force (a constant value within a range of 500 to 1,000 mN / cm ² ). C2, product code V436) is pressed and allowed to stand for about 1 minute, and then when the plain paper is gently peeled off, no transfer is observed at all, and the state is completely cured.

Mercury lamps and gas / solid lasers are mainly used as actinic light sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing UV light-curable ink jet recording ink compositions. It has been. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as light sources for photo-curable ink jets.
In addition, a light emitting diode (LED) and a laser diode (LD) can be used as active ray sources. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. When even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit active radiation centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. A particularly preferred actinic radiation source in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 340 to 400 nm.
The ink jet recording method of the present invention is suitable for a soft packaging package, and it is preferable to use a recording medium having a relatively thin film thickness as described above. In this case, it is preferable to use a UV-LED light source because deformation and shrinkage of the recording medium due to heat are suppressed.
The amount of energy required for complete curing varies depending on the composition, particularly the type and content of the photopolymerization initiator, but the illuminance on the recording medium is preferably about 100 to 10,000 mJ / cm ² .

In the complete curing step, it is preferable that the atmosphere around the surface of the recording medium is an oxygen-poor atmosphere when irradiated with actinic rays. Although it is known that the energy of actinic rays required for curing can be reduced by suppressing the oxygen concentration in the curing atmosphere, the present invention is effective in improving migration, odor, and shrink, which are important as package print characteristics. Has been found to be.
In general, radically-polymerized ink compositions are particularly prone to oxygen polymerization inhibition on the surface in contact with air, and surface curing failure is particularly likely to occur. Due to this curable deterioration of the surface, the monomer remains in the film, or the formation of a cross-linked structure of the film with the polyfunctional monomer makes the performance of keeping low molecular components in the film insufficient, and migration and odor are remarkably deteriorated. However, it is presumed that exposure in an environment having a low oxygen concentration reduces the degree of inhibition of oxygen polymerization and improves migration and odor.
Moreover, only the surface of the cured film is selectively subjected to oxygen polymerization inhibition, resulting in a difference in curability from the inside of the film where good curability is obtained, resulting in a distribution in volume shrinkage, resulting in packaging use. A thin support body tends to cause shrinkage. Also in this regard, it is presumed that the shrinkage can be improved by making the volume shrinkage rate uniform between the film surface and the inside by exposing in an environment having a low oxygen concentration.

In the present invention, it is preferable to perform active ray irradiation in an oxygen-poor atmosphere having an oxygen partial pressure of 0.15 atm or less.
Usually, since the partial pressure of oxygen is 0.21 atm (atmospheric pressure) under the atmosphere (1 atm), in order to reduce the partial pressure of oxygen to 0.15 atm or less, (a) the atmosphere at the time of exposure is reduced. It can be achieved by setting the pressure to 0.71 atm or less, or (b) mixing a gas other than air and oxygen (for example, an inert gas such as nitrogen or argon) by 40 vol% or more with respect to air.
The poor oxygen atmosphere in the present invention is not particularly limited, and any of the above methods can be used.

The oxygen partial pressure is more preferably 0.10 atm or less, further preferably 0.08 atm or less, and particularly preferably 0.05 atm or less.
There is no restriction | limiting in particular in the minimum of oxygen partial pressure. By substituting the vacuum or atmosphere with a gas other than air (eg, nitrogen), the oxygen partial pressure can be reduced to virtually zero, which is also a preferred method.
The oxygen concentration due to the inert gas replacement is preferably controlled to 0.01% by volume to 10% by volume (at this time, the oxygen partial pressure is controlled to 0.0001 atm to 0.10 atm). It is more preferable to control to 1 to 5% by volume.

  As a means for controlling the oxygen concentration in the curing atmosphere to 0.01 volume% to 10 volume%, for example, there is a method in which the image forming apparatus is closed and a nitrogen atmosphere or a carbon dioxide atmosphere is used. Nitrogen supply means includes, for example, a method using a nitrogen cylinder or a device that separates only nitrogen gas from the air using the difference in permeability between oxygen and nitrogen through the hollow fiber membrane. As a means for supplying carbon dioxide, there is a supply method using a cylinder.

The inert gas refers to general gases such as N ₂ , H ₂ , and CO ₂ and rare gases such as He, Ne, and Ar. Among these, N ₂ (nitrogen gas) is preferably used because of safety, availability, and cost.

  The term “under reduced pressure” refers to a state of 500 hPa (0.05 MPa) or less, preferably 100 hPa (0.01 MPa) or less.

(Step b) A step of applying the undercoat composition (II) onto the undercoat layer (1) and irradiating the applied undercoat composition (II) with an actinic ray to semi-cure the inkjet recording method of the present invention, (Process b) It has the process of apply | coating undercoat composition (II) on undercoat layer (1), irradiating actinic light to the provided undercoat composition (II), and semi-hardening. The undercoat composition (II) contains (Component A) a radically polymerizable compound and (Component B) a polymerization initiator, and a polyfunctional ethylenically unsaturated compound as Component A is 60% by mass or more of the composition. contains. The undercoat composition (II) will be described later.
In the step b, (step b ¹ ) applying the undercoat composition (II) onto the undercoat layer (1), and (step b ² ) irradiating the applied undercoat composition (II) with actinic rays. Thus, the semi-curing step (hereinafter, also referred to as “semi-curing step”) is performed in this order. Hereinafter, the process b ¹ and the process b ² will be described separately.

(Step b ¹ ) Step of applying undercoat composition (II) onto undercoat layer (1) In the present invention, undercoat composition (II) is an undercoat layer formed by completely curing undercoat composition (I). (1) It is given above.
As a means for applying the undercoat composition (II), a coating apparatus or an inkjet nozzle can be used, and an inkjet nozzle is preferably used. The coating apparatus, the coating device mentioned in the above step a ¹ is exemplified.

The undercoat composition (II) is preferably applied to the same area as the image formed by ejecting ink droplets on the recording medium in step c or an area wider than the image, and covers the entire area where the image can be formed. It is preferable to be provided so as to cover.
Further, the application amount (mass ratio per unit area) of the undercoat composition (II) is 0.05 when the maximum application amount (per color) of the ink composition (III) per unit area is 1. Is preferably in the range of ˜5, more preferably in the range of 0.07 to 4, and particularly preferably in the range of 0.1 to 3.

(Step b ² ) Step of semi-curing the applied undercoat composition (II) by irradiating actinic rays (semi-curing step)
The inkjet recording method of the present invention includes a step of semi-curing by irradiating the undercoat composition (II) applied on the undercoat layer (1) with actinic rays.
In the present invention, “semi-cured” means partially cured (partially cured; partial curing), and the undercoat composition (II) and / or the ink composition (III) described below (hereinafter simply referred to as “ink”). Is also partially cured but not completely cured. When the undercoat composition (II) applied on the undercoat layer (1) or the ink composition (III) ejected on the undercoat composition (II) is semi-cured, the degree of curing is not uniform. May be. For example, the undercoating composition (II) and / or the ink composition (III) is preferably cured in the depth direction.

Examples of the method of semi-curing the undercoat composition (II) include a method of irradiating the undercoat composition (II) with actinic rays, that is, a method of causing a curing reaction by exposure.
The method of causing an actinic ray to cause a semi-curing reaction is a method of insufficiently carrying out the polymerization reaction of the ethylenically unsaturated compound on the surface of the undercoat composition (II) applied on the undercoat layer (1). .
As the actinic rays, in addition to ultraviolet rays, for example, visible rays, α rays, γ rays, X rays, electron rays, and the like can be used. Among these, the active light is preferably ultraviolet light or visible light, and particularly preferably ultraviolet light, from the viewpoint of cost and safety.
The amount of energy required for semi-curing the undercoat composition (II) varies depending on the composition, particularly the type and content of the photopolymerization initiator, but is preferably about 1 to 500 mJ / cm ² .

Mercury lamps and gas / solid lasers are mainly used as exposure light sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing UV photocurable ink jet recording ink compositions. ing. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as light sources for photo-curable ink jets.
In addition, a light emitting diode (LED) and a laser diode (LD) can be used as active ray sources. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. When even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit active radiation centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. A particularly preferred actinic radiation source in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 340 to 400 nm.
The maximum illumination intensity on the LED recording medium is preferably 10 to 2,000 mW / cm ^2, more preferably 20 to 1,000 mW / cm ^2, is 50 to 800 mW / cm ² It is particularly preferred.
Suitable exposure means for semi-curing the undercoat liquid include a metal halide lamp, a mercury lamp, and an LED light source. Among these, an LED light source is preferable. The ink jet recording method of the present invention is suitable for a soft packaging package, and it is preferable to use a recording medium having a relatively thin film thickness as described above. In this case, it is preferable to use a UV-LED light source because deformation and shrinkage of the recording medium due to heat are suppressed.

When the primer composition (II) containing an ethylenically unsaturated compound that is radically polymerizable is polymerized in an atmosphere containing a large amount of oxygen such as in the air or partially substituted with an inert gas, oxygen is used. Therefore, radical polymerization tends to be inhibited on the surface of the droplet of the undercoat composition (II) applied on the recording medium. As a result, the semi-curing becomes non-uniform, the curing progresses more inside the undercoat layer (2) droplets, and the surface curing tends to be delayed. Here, the undercoat layer (2) is a layer of the undercoat composition (II).
In the semi-curing step, it is preferable that the surface of the undercoat composition (II) on the side not in contact with the undercoat layer (1) is not cured.

In the present invention, when the radically polymerizable undercoat composition (II) is used in the presence of radical polymerization-inhibiting oxygen and partially photocured, the undercoat composition (II) is cured more internally than externally. More progress.
In particular, the surface of the undercoat composition (II) is likely to inhibit the polymerization reaction due to the influence of oxygen in the air as compared to the inside. Therefore, the undercoat composition (II) can be semi-cured by controlling the application conditions of actinic rays.

The application of actinic rays promotes the generation of active species due to decomposition of the polymerization initiator, and the increase in the active species and the temperature increase cause polymerization reaction due to the active species or a curing reaction due to polymerization or crosslinking of the crosslinkable material. Promoted.
Moreover, thickening (viscosity increase) can also be suitably performed by actinic ray irradiation.

In the semi-curing step, in the case of a curing reaction based on an ethylenically unsaturated compound, the unpolymerization rate can be quantitatively measured by the reaction rate of the ethylenically unsaturated group.
When the semi-cured state of the undercoat liquid is realized by a polymerization reaction of an ethylenically unsaturated compound that starts polymerization by irradiation with active energy rays, the unpolymerized rate (A (after polymerization) ) / A (before polymerization)) is preferably 0.2 or more and 0.9 or less, more preferably 0.3 or more and 0.9 or less, and 0.5 or more and 0.9 or less. Is particularly preferred.
Here, A (after polymerization) is the absorbance of the infrared absorption peak due to the ethylenically unsaturated group after the polymerization reaction, and A (before polymerization) is the infrared absorption peak due to the ethylenically unsaturated group before the polymerization reaction. Absorbance. For example, when the ethylenically unsaturated compound contained in the undercoat liquid is an acrylate monomer or a methacrylate monomer, an absorption peak based on a polymerizable group (acrylate group, methacrylate group) can be observed in the vicinity of 810 cm ⁻¹ , and the absorbance of the peak Therefore, it is preferable to define the unpolymerized rate.
Moreover, as a means for measuring an infrared absorption spectrum, a commercially available infrared spectrophotometer can be used, which may be either a transmission type or a reflection type, and is preferably selected as appropriate in the form of a sample. For example, it can be measured using an infrared spectrophotometer FTS-6000 manufactured by BIO-RAD.

(Step c) Step of discharging the ink composition (III) onto the semi-cured undercoating composition (II) The ink jet recording method of the present invention comprises the step of forming an ink on the semi-curing undercoating composition (II). A step of discharging the composition (III) (hereinafter, also referred to as “image forming step”).
By ejecting the ink composition (III) onto the semi-cured undercoat composition (II), the image quality and flexibility of the obtained printed matter are excellent.

  As a means for ejecting the ink composition by the ink jet method, it is preferable to use an ink jet head. As an inkjet head, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electrical signal is converted into an acoustic beam into ink A head such as an acoustic ink jet system that irradiates and ejects ink using radiation pressure, or a thermal ink jet (bubble jet (registered trademark)) system that uses ink to form bubbles by heating the ink is suitable. It is.

In the image forming step, the ink composition (III) is ejected onto the semi-cured undercoat composition (II) by an ink jet method.
There is no restriction | limiting in particular as an inkjet recording device which can be used for the inkjet recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known inkjet recording apparatus including a commercially available product can discharge the ink composition onto the recording medium in the image forming step of the inkjet recording method of the present invention.

Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and an active energy ray source.
The ink supply system includes, for example, an original tank containing an ink composition, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400 × 400 to 1,600 ×. It can be driven so that it can discharge at a resolution of 1,600 dpi, more preferably 1,200 × 1,200 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

Since the ink composition preferably has a constant temperature for the ejected ink composition, the ink jet recording apparatus preferably includes a means for stabilizing the ink composition temperature. The parts to be kept at a constant temperature are all the piping systems and members from the ink tank (intermediate tank if there is an intermediate tank) to the nozzle ejection surface. That is, heat insulation and heating can be performed from the ink supply tank to the inkjet head portion.
The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors at each piping site and perform heating control according to the ink flow rate and the environmental temperature. The temperature sensor can be provided near the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of heat energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

  It is preferable to keep the temperature of the in-composition (III) at the time of discharge as constant as possible. Accordingly, in the present invention, the temperature control range of the ink composition (III) is preferably set to ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and further preferably set temperature ± 1 ° C. Is appropriate.

  The droplet ejection interval from when the undercoat composition (II) is applied until the first droplet of the ink composition (III) is deposited is preferably within the range of 5 μs or more and 10 seconds or less. The droplet ejection interval of the ink droplets is more preferably 10 μs to 5 seconds, and particularly preferably 20 μs to 5 seconds.

  In the ink jet recording method of the present invention, the ink composition (III) is ejected onto the semi-cured undercoat composition (II) to form an image, and then the ejected ink composition (III) is semi-finished. Although the process of hardening may be included, when performing the said whole hardening process immediately after, it is more preferable not to include.

In the ink jet recording method of the present invention, the ink composition (III) may be used alone or in combination of two or more.
For example, when forming a color image, it is preferable to use at least each color ink composition of yellow, cyan, magenta, and black, and more preferable to use each color ink composition of white, yellow, cyan, magenta, and black. preferable.
Further, a light color ink composition such as light magenta or light cyan, a special color ink composition such as orange, green and violet, a clear ink composition, a metallic ink composition, or the like may be used.

In the ink jet recording method of the present invention, when two or more ink compositions (III) are ejected, one ink composition (III) is ejected and then another one ink composition (III) It is preferable to include a step of semi-curing the discharged ink composition (III) before discharging the ink. That is, the inkjet recording method of the present invention includes a step of ejecting the ink composition (III) onto the semi-cured undercoat composition (II) for each ink composition used, and the ejected ink. It is preferable to include a step of semi-curing the composition (III). The effect of this invention can be exhibited more as it is the said aspect.
The semi-curing step in the case of applying two or more kinds of ink compositions (III) is the same as the semi-curing step described in the above step b ² , and the exposure apparatus and exposure conditions used, and preferred embodiments Is the same.
Further, when the entire curing step is performed immediately afterward, the ink jet recording method of the present invention may or may not include a step of semi-curing the last ejected ink composition (III). However, from the viewpoint of cost and simplicity, it is preferable not to include them.
When two or more kinds of ink compositions (III) are ejected, any of the ink compositions (III) is applied on the semi-cured undercoat composition (II), on the ejected ink composition (III), or The ink composition is preferably discharged onto the semi-cured ink composition (III). That is, it is preferable that any ink composition is directly contacted or discharged onto the semi-cured undercoat composition (II) via another ink composition layer.

  In the ink jet recording method of the present invention, the order of the ink compositions to be ejected is not particularly limited, but is preferably applied to the recording medium from an ink composition having a low brightness, and yellow, cyan, magenta, black Is preferably applied on the recording medium in the order of black → magenta → cyan → yellow. In addition, when white is added to this, it is preferable to apply it on the recording medium in the order of black → magenta → cyan → yellow → white. Furthermore, the present invention is not limited to this, and the ink set of the present invention including at least seven colors of yellow, light cyan, light magenta, cyan, magenta, black and white ink compositions can be preferably used. In this case, it is preferable to apply the recording material in the order of black → magenta → cyan → yellow → light magenta → light cyan → white.

(Step d) Step of irradiating the undercoat composition (II) and the ink composition (III) with actinic rays to cure the whole The ink jet recording method of the present invention comprises (Step d) the undercoat composition (II) and the ink. A step of irradiating the composition (III) with actinic rays to cure the entire composition (overall curing step) is included. After the image forming step, a whole curing step of curing the entire semi-cured undercoat composition (II) and ink composition (III) is included.
The overall curing step is a step of curing the entire semi-cured undercoat composition (II) and ink composition (III), and the semi-cured undercoat composition (II) and ink composition (III) It is preferable to completely cure.

Overall curing step is carried out by irradiation with actinic rays, a preferred embodiment thereof, the exposure conditions and exposure apparatus in the step a ² is used, preferable embodiments thereof are also the same. That is, it is preferable to perform the whole curing process in an oxygen-poor atmosphere.

In the inkjet recording method of the present invention, it is also preferable to laminate the upper part of the printed material after performing inkjet printing on the recording medium.
By laminating, elution, blocking, and odor of the components of the composition from the printed material can be suppressed, and it can be preferably used particularly for food packaging.

The ink jet recording apparatus particularly preferably used in the present invention will be further described in detail. The above-described ink jet recording method of the present invention is preferably carried out by the ink jet recording apparatus of the present invention described below.
The ink jet recording apparatus of the present invention comprises a conveying means for conveying a recording medium, an applying means for applying an undercoat composition (I) on the recording medium, and an undercoat composition (I) applied on the recording medium. A completely curing means for completely curing; an imparting means for imparting the undercoat composition (II) onto the undercoat layer (1) formed by complete curing of the undercoat composition (I); and an applied undercoat composition (II Semi-curing means for semi-curing), discharging means for inkjet discharging the ink composition (III) onto the semi-cured undercoat composition (II), and the semi-cured undercoat liquid (II) and ink composition And a complete curing means for completely curing the product (III).
The ink jet recording apparatus of the present invention is preferably a so-called single pass ink jet recording apparatus.

FIG. 1 is a schematic diagram showing an example of an ink jet recording apparatus preferably used in the present invention. The recording medium 12 stretched by the delivery roller 24 and the take-up roller 26, which is a conveying means of the recording medium 12, is conveyed in the direction of arrow A, and the undercoat composition (I) is applied by the undercoat composition (I) coating roller 14. The undercoat composition (I) is completely cured by the nitrogen purge exposure light source unit 15 which is a complete curing means for the undercoat composition (I). Next, the undercoat composition (II) is applied onto the undercoat layer (1) formed by complete curing of the undercoat composition (I) by the applying means 16 of the undercoat composition (II). Subsequently, the undercoat composition (II) is semi-cured by the exposure light source 17 for semi-curing the undercoat composition (II). Subsequently, the ink compositions of the respective colors (K: black, Y: yellow, M: magenta, C: cyan, W: white) are ejected by the inkjet heads 18K, 18C, 18M, 18Y, and 18W that discharge the ink compositions of the respective colors. ) Are ejected, and the ejected black, yellow, magenta and cyan ink compositions are semi-cured by the semi-curing exposure light sources 20K, 20C, 20M and 20Y installed immediately after the inkjet heads 18K, 18C, 18M and 18Y. Is done. Finally, the nitrogen purge exposure light source unit 22 exposes the recording medium in an oxygen-poor atmosphere, and the entire under-cured undercoat composition (II) and ink composition (III) are cured.
In the nitrogen purge exposure light source units 15 and 22, for example, the LED light source is surrounded by an inert gas blanket and is connected to an inert gas generator via an inert gas pipe to operate the inert gas generator. When it does, the aspect by which the air in a blanket is substituted by an inert gas is mentioned preferably. As described above, N ₂ or the like can be used as the inert gas.
In FIG. 1, a nip roll 28 is provided to improve the conveyance system. By completely curing the undercoating composition (I), the ink jet recording method of the present invention enables the use of a nip roll, realizes more accurate transportability, and suppresses registration misalignment (landing position deviation). . The nip roll 28 is not essential, and an image forming apparatus that does not have a nip roll may be used.

(Undercoat Composition (I), Undercoat Composition (II), and Ink Composition (III))
The undercoat composition (I), the undercoat composition, and the ink composition (III) used in the inkjet recording method of the present invention will be described. In the present invention, the composition (I), the composition (II) and the composition (III) contain (Component A) a radically polymerizable compound and (Component B) a polymerization initiator.
Composition (I) contains an acrylate oligomer as component A, and composition (II) and composition (III) contain polyfunctional ethylenically unsaturated compound as component A in an amount of 60% by mass or more of each composition.

The composition (I), composition (II) and composition (III) used in the present invention are oily liquid compositions curable by actinic rays. “Actinic light” is radiation that can give energy to generate a starting species in the composition by irradiation, and includes α rays, γ rays, X rays, ultraviolet rays, visible rays, electron rays, and the like. Of these, ultraviolet rays and electron beams are preferable from the viewpoint of curing sensitivity and device availability, and ultraviolet rays are more preferable.
In the present invention, the ink composition (III) is an actinic ray curable ink composition and is different from an aqueous ink composition or a solvent ink composition. The ink composition (III) preferably contains as little water and volatile solvent as possible, and even if it contains, it is preferably 1% by mass or less based on the total mass of the ink composition. More preferably, it is less than or equal to 0.1% by weight, and still more preferably less than or equal to 0.1% by weight.

In the present invention, the composition (I) and the composition (II) may contain a colorant, which will be described later, but preferably contain or do not contain a white colorant. More preferred.
The composition (I) and the composition (II) preferably do not contain a colorant, or the content of the colorant is preferably 1% by mass or less, and do not contain a colorant, or the content of the colorant is 0. More preferably, it is 5 mass% or less, it does not contain a coloring agent, or it is still more preferable that content of a coloring agent is 0.1 mass% or less, and it is especially preferable not to contain a coloring agent.
In addition, in order to suppress the coloring by yellowing of composition (I) and composition (II), the aspect of containing a small amount of blue pigment etc. is not excluded.
Hereinafter, the composition (I), the composition (II) and the composition (III) used in the present invention will be described in detail.

<(Component A) radical polymerizable compound>
In the present invention, each of the composition (I), the composition (II), and the composition (III) contains (Component A) a radically polymerizable compound.
As the radical polymerizable compound, an ethylenically unsaturated compound is preferable, and a known ethylenic compound can be used. Examples thereof include (meth) acrylate compounds, vinyl ether compounds, allyl compounds, N-vinyl compounds, and unsaturated carboxylic acids. it can. For example, the radically polymerizable monomer described in JP2009-22214A, the polymerizable compound described in JP2009-209289A, and the ethylenically unsaturated compound described in JP2009-191183A can be mentioned.
The ethylenically unsaturated compound is preferably a (meth) acrylate compound, and more preferably an acrylate compound.

[Acrylate oligomer]
Composition (I) contains an acrylate oligomer as component A. In addition, composition (II) and composition (III) may contain an acrylate oligomer. When the composition (I) contains an acrylate oligomer, a printed matter having an image excellent in adhesion to the substrate can be obtained.
In the present invention, the “acrylate oligomer” is an oligomer having at least one acryloyl group or methacryloyl group, and can be appropriately selected from known acrylate oligomers. The acrylate oligomer preferably has 1 to 12 acryloyl groups or methacryloyl groups in total, more preferably 1 to 6, and still more preferably 2 to 6.
In addition, the acrylate oligomer includes not only an oligomer having an acryloyl group but also an oligomer having a methacryloyl group, and is preferably an oligomer having an acryloyl group.
In the present invention, the oligomer preferably has a viscosity at room temperature (25 ° C.) of 0.1 Pa · s (100 cP) or more. Moreover, it is preferable that the upper limit of the weight average molecular weight of an oligomer is 20,000 or less. The viscosity at room temperature is measured with a RE80 viscometer manufactured by Toki Sangyo Co., Ltd.
The acrylate oligomer preferably has a weight average molecular weight of 20,000 or less, and more preferably 10,000 or less. In the present invention, the weight average molecular weight is measured by a gel permeation chromatography (GPC) method and is determined by conversion with standard polystyrene. Specifically, for example, GPC uses HLC-8220GPC (manufactured by Tosoh Corporation), and TSKgeL SuperHZM-H, TSKgeL SuperHZ4000, TSKgeL SuperHZ2000 (4.6 mm ID × 15 cm, manufactured by Tosoh Corporation) are used as columns. Three are used and THF (tetrahydrofuran) is used as an eluent. As conditions, the sample concentration is 0.35% by mass, the flow rate is 0.35 ml / min, the sample injection amount is 10 μl, the measurement temperature is 40 ° C., and an IR detector is used. In addition, the calibration curve is “standard sample TSK standard, polystyrene” manufactured by Tosoh Corporation: “F-40”, “F-20”, “F-4”, “F-1”, “A-5000”, It is prepared from 8 samples of “A-2500”, “A-1000”, “n-propylbenzene”.

The oligomer in the acrylate oligomer may be any oligomer. For example, olefin-based (ethylene oligomer, propylene oligomer, butene oligomer, chlorinated polyolefin oligomer, etc.), vinyl-based (styrene oligomer, vinyl alcohol oligomer, vinyl pyrrolidone oligomer acrylate) Oligomers, methacrylate oligomers, etc.), diene systems (butadiene oligomers, chloroprene rubber, pentadiene oligomers, etc.), ring-opening polymerization systems (di-, tri-, tetraethylene glycol, polyethylene glycol, polyethylimine, etc.), polyaddition systems (urethane) Acrylate, polyester acrylate, polyamide oligomer, polyisocyanate oligomer), addition condensation oligomer (phenol resin) Amino resins, xylene resins, ketone resins, etc.) and the like.
Among these, as the acrylate oligomer, urethane acrylate and polyester acrylate are preferable, and urethane acrylate is particularly preferable.

  Examples of urethane acrylates include aliphatic urethane acrylates and aromatic urethane acrylates, with aliphatic urethane acrylates being more preferred. The urethane acrylate is preferably 1-4 functional, more preferably 1 or bifunctional, and even more preferably bifunctional. For details, the oligomer handbook (supervised by Junji Furukawa, Chemical Industry Daily Co., Ltd.) can also be referred to.

Moreover, what is shown below is illustrated as a commercial item of an acrylate oligomer.
Examples of the urethane acrylate include CN991, CN2922, CN9011, CN992, manufactured by Sartomer, R1204, R1211, R1213, R1217, R1218, R1301, R1302, R1303, R1304, R1306, R1308, R1901 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. , R1150, etc., and Ebecryl series (for example, Ebecryl 230, 270, 4858, 8402, 8804, 8807, 8803, 9260, 1290, 1290K, 5129, 4842, 8210, 210, 4827, 6700, manufactured by Daicel Cytec Co., Ltd. 4450, 220), NK Oligo U-4HA, U-6HA, U-15HA, U-108A, U-200AX, etc., manufactured by Shin-Nakamura Chemical Co., Ltd., manufactured by Toagosei Co., Ltd. Aronix M-1100, M-1200, M-1210, M-1310, M-1600, M-1960 etc. are mentioned.
Examples of the polyester acrylate include CN146, CN820, CN147 manufactured by Sartomer, and the Ebecryl series manufactured by Daicel-Cytech Co., Ltd. (for example, Ebecryl 770, IRR467, 81, 84, 83, 80, 675, 800, 810, 812, 1657). 1810, IRR302, 450, 670, 830, 870, 1830, 1870, 2870, IRR267, 813, IRR483, 811, etc.), Aronix M-6100, M-6200, M-6250, M manufactured by Toagosei Co., Ltd. -6500, M-7100, M-8030, M-8060, M-8100, M-8530, M-8560, M-9050 and the like.

An acrylate oligomer may be used individually by 1 type, and may use 2 or more types.
The content of the acrylate oligomer in the composition (I) is preferably 60% by mass or more, preferably 65 to 99% by mass, and 70 to 97% by mass with respect to the total mass of the composition (I). % Is more preferable. When the content of the acrylate oligomer is within the above range, sufficient substrate adhesion can be obtained.
In addition, as for composition (II) and composition (III), it is preferable that content of an acrylate oligomer is 0-30 mass% of each composition, It is more preferable that it is 0-15 mass%, It is more preferable that it is 5 mass%, and it is especially preferable not to contain. When the content of the acrylate oligomer is within the above range, the discharge property is excellent and a good image is obtained.

[Polyfunctional ethylenically unsaturated compound]
The composition (II) and the composition (III) each contain 60% by mass or more of a polyfunctional ethylenically unsaturated compound with respect to the total mass of the composition. When the content of the polyfunctional ethylenically unsaturated compound is less than 60% by mass, migration easily occurs and odor is generated.
The content of the polyfunctional ethylenically unsaturated compound in the composition (II) and the composition (III) is preferably 70 to 98% by mass, and more preferably 75 to 97% by mass.
The composition (I) preferably contains a polyfunctional ethylenically unsaturated compound from the viewpoints of curability and flexibility.

In the present invention, the composition (I), the composition (II) and the composition (III) preferably contain a polyfunctional (meth) acrylate compound as a polyfunctional ethylenically unsaturated compound. ) More preferably, an acrylate compound is contained, more preferably a bifunctional acrylate compound, and particularly preferably a diacrylate monomer.
Bifunctional (meth) acrylate monomers are preferred because of their low viscosity and excellent reactivity.
In the present invention, the monomer means a radical polymerizable compound having a viscosity at room temperature (25 ° C.) of less than 0.1 Pa · s. The monomer preferably has a molecular weight (weight average molecular weight in the case of molecular weight distribution) of less than 1,000, and an oligomer is generally a weight of a finite number of monomers (generally 5 to 100) bonded thereto. Preferably, the polymer has a weight average molecular weight of 1,000 or more.

Preferred examples of the polyfunctional ethylenically unsaturated compound include di (meth) acrylic acid esters of aliphatic hydrocarbon diols having 6 to 12 carbon atoms. The hydrocarbon diol may be any of a linear hydrocarbon diol, a branched hydrocarbon diol and a cyclic hydrocarbon diol, and a linear hydrocarbon diol and a branched hydrocarbon diol are preferably exemplified.
Di (meth) acrylic acid esters of aliphatic hydrocarbon diols having 6 to 12 carbon atoms are preferred because of their low viscosity and their relatively low odor.
Examples of the di (meth) acrylic acid ester of an aliphatic hydrocarbon diol having 6 to 12 carbon atoms include 1,6-hexanediol di (meth) acrylate, 1,7-heptanediol di (meth) acrylate, 1,8- Octanediol di (meth) acrylate 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, 3-methyl-1,5 -Pentanediol di (meth) acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate Is preferably exemplified.
Among these, decanediol diacrylate, dodecanediol diacrylate, and 3-methyl-1,5-pentanediol dimethacrylate are more preferable, and 3-methyl-1,5-pentanediol diacrylate is more preferable.
In the present invention, the (meth) acrylate monomer means a compound containing one or more (meth) acryloyloxy groups in the molecule and having a viscosity of less than 0.1 Pa · s at room temperature (25 ° C.). To do. When the viscosity is within the above range, it is possible to achieve both migration of printed matter and suppression of odor and reactivity.

  Specific examples of other bifunctional (meth) acrylate compounds include dipropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and ethylene oxide (EO) modification. Neopentyl glycol di (meth) acrylate, propylene oxide (PO) modified neopentyl glycol di (meth) acrylate, EO modified hexanediol di (meth) acrylate, PO modified hexanediol di (meth) acrylate, tripropylene glycol di (meth) ) Acrylate and triethylene glycol di (meth) acrylate are preferred.

  Trifunctional or higher functional (meth) acrylate compounds include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, trimethylolethane tri (meth) acrylate, and trimethylol. Examples include propane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, and oligoester (meth) acrylate.

The composition (II) and the composition (III) preferably contain polyalkylene glycol diacrylate as a polyfunctional ethylenically unsaturated compound (more preferably, a polyfunctional ethylenically unsaturated monomer).
The polyalkylene glycol diacrylate is preferably polyethylene glycol diacrylate or polypropylene glycol diacrylate.
Moreover, the repeating number of the alkylene glycol unit in polyalkylene glycol diacrylate, ie, the repeating number of the alkyleneoxy group, is 2 or more, preferably 2 to 100, and more preferably 2 to 20.
The content of the polyalkylene glycol diacrylate in the composition (II) and the composition (III) is preferably 1 to 50% by mass, and preferably 2 to 40% by mass, based on the total mass of the composition. More preferably, it is 5-30 mass%. In the above embodiment, the reactivity is excellent and the amount of the initiator to be used can be reduced.

[Monofunctional ethylenically unsaturated compound]
Composition (I), composition (II), and composition (III) may contain a monofunctional ethylenically unsaturated compound as component A. Examples of the monofunctional ethylenically unsaturated compound include a monofunctional (meth) acrylate compound, a monofunctional (meth) acrylamide compound, a monofunctional aromatic vinyl compound, a monofunctional vinyl ether compound, and a monofunctional N-vinyl compound.

  Examples of monofunctional (meth) acrylate compounds include hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-octyl (meth) acrylate, isoamyl (meth) acrylate, decyl (meth) acrylate, and isodecyl (meth). Acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl diglycol (meth) acrylate, butoxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 4-bromobutyl (meth) acrylate, Noethyl (meth) acrylate, benzyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) Ethyl (meth) acrylate, 2,2,2-tetrafluoroethyl (meth) acrylate, 1H, 1H, 2H, 2H-perfluorodecyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate 2,4,5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, glycidyloxybutyl (meta Acrylate, glycidyloxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (Meth) acrylate, 2-hydroxybutyl (meth) acrylate,

4-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, trimethoxy Silylpropyl (meth) acrylate, trimethylsilylpropyl (meth) acrylate, polyethylene oxide monomethyl ether (meth) acrylate, oligoethylene oxide monomethyl ether (meth) acrylate, polyethylene oxide (meth) acrylate, oligoethylene oxide (meth) acrylate, oligoethylene Oxide monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl -Ter (meth) acrylate, dipropylene glycol (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, oligopropylene oxide monoalkyl ether (meth) acrylate, 2-methacryloyloxytyl succinic acid, 2-methacryloyloxyhexa Hydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl ( (Meth) acrylate, ethylene oxide (EO) modified phenol (meth) acrylate, EO modified cresol (meth) acrylate, EO modified nonyl Enol (meth) acrylate, propylene oxide (PO) modified nonylphenol (meth) acrylate, EO modified-2-ethylhexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopenta Examples include nyl (meth) acrylate, (3-ethyl-3-oxetanylmethyl) (meth) acrylate, and phenoxyethylene glycol (meth) acrylate.

  Examples of the (meth) acrylamide compound include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, Nn-butyl (meth) acrylamide, N -T-butyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl ( And (meth) acrylamide and (meth) acryloylmorpholine.

  Examples of the aromatic vinyl compound include styrene, dimethyl styrene, trimethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester, 3-methyl styrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene, 3-octylstyrene, 4-octylstyrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allylstyrene, isopropenylstyrene, butenylstyrene, octenylstyrene, 4-t-butoxyca Bonirusuchiren include 4-t-butoxystyrene.

Further, examples of the ethylenically unsaturated compound include vinyl esters (vinyl acetate, vinyl propionate, vinyl versatate, etc.), allyl esters (eg, allyl acetate), halogen-containing monomers (vinylidene chloride, vinyl chloride, etc.) ), Vinyl ether (methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxy vinyl ether, 2-ethylhexyl vinyl ether, methoxyethyl vinyl ether, cyclohexyl vinyl ether, chloroethyl vinyl ether, triethylene glycol divinyl ether, etc.), vinyl cyanide ((meth) acrylonitrile, etc.) Olefins (ethylene, propylene, etc.), N-vinyllactams (N-vinylcaprolactam, etc.) and the like.
Examples of the ethylenically unsaturated compound include unsaturated carboxylic acids such as itaconic acid, crotonic acid, isocrotonic acid and maleic acid, salts thereof, and anhydrides having an ethylenically unsaturated group.

  More specifically, Shinzo Yamashita “Cross-linking agent handbook” (1981, Taiseisha); Kato Kiyosumi “UV / EB curing handbook (raw material)” (1985, Polymer publication society); Ed., “Application and Market of UV / EB Curing Technology” on page 79 (1989, CMC Publishing); “Polyester Resin Handbook” by Eiichiro Takiyama (1988, Nikkan Kogyo Shimbun) Commercially available products or radically polymerizable or crosslinkable monomers, oligomers and polymers known in the industry can be used.

A radically polymerizable compound may be used individually by 1 type, or may use 2 or more types together.
From the viewpoint of curability, the total content of component A in the composition (I) is preferably 80 to 99% by mass, preferably 90 to 98% by mass, and 93 to 98%. More preferably, it is mass%.
From the viewpoint of curability, the total content of component A in the composition (II) is preferably 80 to 99% by mass, preferably 85 to 98% by mass, and 90 to 97% by mass. % Is more preferable.
From the viewpoint of curability, the total content of component A in the composition (III) is preferably 70 to 98% by mass, more preferably 75 to 95% by mass, and more preferably 80 to 93%. More preferably, it is mass%.

<(Component B) Polymerization initiator>
In the present invention, the composition (I), the composition (II) and the composition (III) contain (Component B) a polymerization initiator.
The polymerization initiator is preferably a radical polymerization initiator, and more preferably a radical photopolymerization initiator.
Polymerization initiators include (a) aromatic ketones, (b) acylphosphine compounds, (c) aromatic onium salt compounds, (d) organic peroxides, (e) thio compounds, (f) hexaarylbiphenyls. An imidazole compound, (g) a ketoxime ester compound, (h) a borate compound, (i) an azinium compound, (j) a metallocene compound, (k) an active ester compound, (l) a compound having a carbon halogen bond, and (m) Examples thereof include alkylamine compounds. These radical polymerization initiators may use the above compounds (a) to (m) alone or in combination. About the detail of the said polymerization initiator, what is described in Paragraph 0090-0116 of Unexamined-Japanese-Patent No. 2009-185186 can be illustrated, for example.
The polymerization initiator in this invention may be used individually by 1 type, or may use 2 or more types together.
Preferred examples of the polymerization initiator include acylphosphine compounds, α-hydroxyketone compounds and / or α-aminoketone compounds. Of these, acylphosphine compounds and / or α-aminoketone compounds are more preferred, and acylphosphine compounds are even more preferred.

  Preferred examples of the acylphosphine compound include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl)- 2-methoxyphenylphosphine oxide, bis (2,6-dimethylbenzoyl) -2-methoxyphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-dimethoxyphenylphosphine oxide, bis (2,6 -Dimethylbenzoyl) -2,4-dimethoxyphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-dipentyloxyphenylphosphine oxide, bis (2,6-dimethylbenzoyl) -2,4- Dipentyloki Phenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,6-dimethylbenzoylethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (LUCIRIN TPO, manufactured by BASF), 2,6-dimethylbenzoylmethoxyphenylphosphine oxide, 2,4,6- Trimethylbenzoyl (4-pentyloxyphenyl) phenylphosphine oxide, 2,6-dimethylbenzoyl (4-pentyloxyphenyl) phenylphosphine And oxide.

  Among these, as the acylphosphine oxide compound, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE 819, manufactured by BASF), bis (2,6-dimethoxybenzoyl) -2,4,4- Trimethylpentylphenylphosphine oxide is preferred, and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide is particularly preferred.

Moreover, as a polymerization initiator, aromatic ketones are preferable from a sclerosing | hardenable viewpoint.
As the aromatic ketones, α-hydroxyketone compounds and / or α-aminoketone compounds are preferable.
As the α-hydroxyketone compound, known compounds can be used. For example, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, Examples include 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone. Among them, a 1-hydroxycyclohexyl phenyl ketone compound is preferable. In the present invention, the 1-hydroxycyclohexyl phenyl ketone compound includes a compound in which 1-hydroxycyclohexyl phenyl ketone is substituted with an arbitrary substituent. As a substituent, it can select arbitrarily in the range which can exhibit the capability as a radical polymerization initiator, Specifically, a C1-C4 alkyl group can be illustrated.
As the α-aminoketone compound, known compounds can be used. Specifically, for example, 2-methyl-1-phenyl-2-morpholinopropan-1-one, 2-methyl-1- [4 -(Hexyl) phenyl] -2-morpholinopropan-1-one, 2-ethyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-benzyl-2-dimethylamino- 1- (4-morpholinophenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one Etc. As commercially available products, IRGACURE907 (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one), IRGACURE369 (2-benzyl-2-dimethylamino-1- (4-morpholino) Phenyl) -1-butanone), IRGACURE 379 (2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone) (above, BASF (Made by company) etc. can illustrate preferably.
Examples of the polymerization initiator include SPEEDCURE 7040 manufactured by LAMBSON and LUCIRIN TPO manufactured by BASF.

In the present invention, the composition (III) preferably contains at least a compound represented by the following formula (1) or formula (2). By using the compound represented by the formula (1) or the formula (2), the amount of migration of components in the film to the outside (migration) is small, the odor of the printed matter is further suppressed, and the curability and blocking resistance are excellent. An ink jet ink composition is obtained.
Moreover, composition (I) and composition (II) may contain the compound represented by following formula (1) or formula (2).

(In Formula (1) and Formula (2), R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, and x and y are each independently Each represents an integer of 2 to 4, j and m each independently represents an integer of 0 to 4, k and n each independently represents an integer of 0 to 3, and j, k, m and n are When it is an integer of 2 or more, a plurality of R ¹ , R ² , R ³ and R ⁴ may be the same or different, and X ¹ includes at least ^one of a hydrocarbon chain, an ether bond and an ester bond x And X ² represents a y-valent linking group containing at least one of a hydrocarbon chain, an ether bond, and an ester bond.)

  The content of the polymerization initiator having a molecular weight of less than 340 in the ink composition (III) is not contained from the viewpoint of suppressing migration, odor and blocking, or exceeds 0% by mass of the entire ink composition. It is preferably 0% by mass or less, not contained, or more preferably greater than 0% by mass and 0.5% by mass or less, not contained, or greater than 0% by mass and 0.3% by mass More preferably, it is particularly preferably not contained.

-Compound represented by Formula (1)-
The ink composition (III) preferably contains a compound represented by the formula (1) as a polymerization initiator.
In formula (1), R ¹ and R ² each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, and the alkyl group having 1 to 5 carbon atoms is linear, branched or cyclic However, it is preferably linear or branched, preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 2 or 3 carbon atoms, and ethyl. More preferably, it is a group or an isopropyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a chlorine atom is preferable.
Among these, R ¹ and R ² are particularly preferably each independently an ethyl group, an isopropyl group, or a chlorine atom.
In formula (1), j represents an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1. When j is an integer of 2 or more, a plurality of R ¹ may be the same or different.
In formula (1), k represents an integer of 0 to 3, preferably 0 to 2, more preferably 0 or 1, and still more preferably 0. When k is an integer of 2 or more, a plurality of R ² may be the same or different.
In formula (1), x represents an integer of 2 to 4, preferably 3 or 4, and more preferably 4.

In formula (1), X ¹ is an x-valent hydrocarbon chain having 2 to 300 carbon atoms which may contain an ether bond (—O—) and / or an ester bond (— (C═O) —O—). An x-valent linking group consisting of
In formula (1), the thioxanthone structure (the structure represented in [] in formula (1)) excluding X ¹ as a linking group has a plurality (x), but they are the same or different from each other. There is no particular limitation. From the viewpoint of synthesis, they are preferably the same.

  In the compound represented by the above formula (1), the position of substitution to thioxanthone is represented as follows.

When the substitution position of X ¹ is 1 to 4 positions, the substitution position of X ¹ is preferably the 2nd, 3rd or 4th position, more preferably the 2nd or 4th position. More preferably, it is a position.
The substitution position of R ¹ is not particularly limited, but is preferably 6-position or 7-position, and more preferably 6-position.
Further, the substitution position of R ² is not particularly limited, but is preferably 1-position, 2-position or 3-position, and more preferably 1-position.

  The compound represented by the formula (1) is preferably a compound represented by the following formula (1 ′).

R ^1, R ^2, j and k in the formula (1 ') are each and R ^1, R ^2, j and k synonymous in the formula (1), and preferred ranges are also the same.
In formula (1 ′), R ¹¹ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group, and more preferably a hydrogen atom.
In formula (1 ′), r each independently represents an integer of 1 to 6, preferably an integer of 1 to 3, more preferably 1 or 2, and still more preferably 1. When r is 2 or more, a plurality of R ¹¹ may be the same or different.
x ′ represents an integer of 2 to 4, preferably 2 or 3, and more preferably 2.
Y ¹ represents a residue obtained by removing a hydrogen atom of x ′ hydroxy groups from a polyhydroxy compound having at least x ′ hydroxy groups, and all (x ′ pieces) from the polyhydroxy compounds having x ′ hydroxyl groups. It is preferable that it is the residue except the hydrogen atom of the hydroxy group of). Specifically, a residue obtained by removing hydrogen atoms of x ′ hydroxy groups from a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, glycerin, trimethylolpropane, ditrimethylolpropane, and pentaerythritol. It is preferably a group, and is preferably a residue obtained by removing all hydrogen atoms from a hydroxy group.
In formula (1 ′), A ¹ represents a group selected from the group consisting of the following (i) to (iii).

(In Formula (i) to Formula (iii), any one of R ¹² and R ¹³ represents a hydrogen atom, the other represents a hydrogen atom, a methyl group, or an ethyl group, a represents an integer of 1 or 2, b represents an integer of 4 or 5, z represents an integer of 1 to 20, * represents a bonding position with the carbonyl carbon, and ** represents a bonding position with Y ^1. )

A ¹ is preferably a group represented by the formula (i), and * — (OCH ₂ CH ₂ ) _z — **, * — (OCH ₂ CH ₂ CH ₂ CH ₂ ) _z — **, or , * —O (CH (CH ₃ ) CH ₂ ) _z — ** is more preferable. In this case, z is more preferably an integer of 3 to 10.

The molecular weight of the compound represented by the formula (1) is preferably 500 to 3,000, more preferably 800 to 2,500, and still more preferably 1,000 to 2,000.
When the molecular weight is 500 or more, elution of the compound from the cured film is suppressed, and an ink composition in which migration, odor, and blocking are suppressed is obtained. On the other hand, when it is 3,000 or less, the steric hindrance of the molecule is small, the degree of freedom of the molecule in the liquid / film is maintained, and high sensitivity is obtained.
In addition, when the compound represented by Formula (1) is a mixture of a plurality of compounds having different carbon numbers and the like, the weight average molecular weight is preferably in the above range.

  Specific examples of the compound represented by the formula (1) are shown below, but the present invention is not limited to the following compounds.

  Among these, the compound (IA) or (IE) is preferable, and the compound (IE) is more preferable.

  As the compound represented by the formula (1), a commercially available compound can also be used. Specifically, SPEEDCURE 7010 (1,3-di ({α- [1-chloro-9-oxo-9H-thioxanthen-4-yl] oxy} acetylpoly [oxy (1-methylethylene)]) oxy) -2 , 2-bis ({α- [1-chloro-9-oxo-9H-thioxanthen-4-yl] oxy} acetylpoly [oxy (1-methylethylene)]) oxymethyl) propane, CAS No. 1003567-83-6) OMNIPOL TX (Polybutyleneglycol bis (9-oxo-9H-thioxanthenyloxy) acetate, CAS No. 813452-37-8).

  The compound represented by the formula (1) can be produced by a known reaction and is not particularly limited. For example, the compound represented by the formula (1 ′) is represented by the following formula (1-1). It can prepare by making the compound and the compound represented by following formula (1-2) react.

Equation (1-1) and formula R ^1, R ^2, R ¹¹ in ^{(1-2), A 1, Y} 1, j, k, r and x 'has the formula (1' R ¹ in), R ² , R ¹¹ , A ¹ , Y ¹ , j, k, r and x ′, and the preferred range is also the same.
The above reaction is preferably performed in the presence of a solvent, and examples of suitable solvents include aromatic hydrocarbons such as benzene, toluene, and xylene.
The catalyst is preferably used in the presence of a catalyst. Examples of the catalyst include sulfonic acid (eg, p-toluenesulfonic acid, methanesulfonic acid), inorganic acid (eg, sulfuric acid, hydrochloric acid, phosphoric acid), Lewis acid (aluminum chloride, three Examples thereof include boron fluoride and organotitanate.
The reaction temperature and reaction time are not particularly limited.
After completion of the reaction, the product can be separated by isolation from the reaction mixture by known means, washing as necessary and drying.

-Compound represented by Formula (2)-
The ink composition (III) preferably contains a compound represented by the formula (2) as a polymerization initiator.

(In the formula (2), R ³ and R ⁴ each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, m represents an integer of 0 to 4, and n represents an integer of 0 to 3. Y represents an integer of 2 to 4, and when m and n are integers of 2 or more, a plurality of R ³ and R ⁴ may be the same or different, and X ² represents a hydrocarbon chain or an ether bond. And represents a y-valent linking group containing at least one of ester bonds.)

In formula (2), R ³ and R ⁴ each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, and the alkyl group having 1 to 5 carbon atoms is linear, branched or cyclic However, it is preferably linear or branched, preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 2 or 3 carbon atoms, and ethyl. More preferably, it is a group or an isopropyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a chlorine atom is preferable. R ³ and R ⁴ are particularly preferably an ethyl group, an isopropyl group, or a chlorine atom.
In formula (2), m represents an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1. When m is an integer of 2 or more, a plurality of R ³ may be the same or different from each other.
In formula (2), n represents an integer of 0 to 3, preferably 0 to 2, more preferably 0 or 1, and still more preferably 0. When n is an integer of 2 or more, a plurality of R ⁴ may be the same or different.
In formula (2), y represents an integer of 2 to 4, preferably 2 or 3, and more preferably 2.

In formula (2), X ² is a y-valent linkage containing at least one selected from the group consisting of a hydrocarbon chain, an ether bond (—O—) and an ester bond (— (C═O) —O—). Represents a group.
In the formula (2), there are a plurality (y) of benzophenone structures (the structures represented in [] in the formula (2)) excluding the linking group X ² , but they are the same or different from each other. There is no particular limitation. From the viewpoint of synthesis, they are preferably the same.

  In the compound represented by the above formula (2), the position of substitution with benzophenone is represented as follows.

When the substitution position of X ² is 1 to 5 positions, the substitution position of X ² is preferably the 2nd or 3rd position, and more preferably the 3rd position.
The substitution position of R ³ is not particularly limited, but is preferably 2′-position or 3′-position, and more preferably 3′-position.
Further, the substitution position of R ⁴ is not particularly limited, but is preferably 2-position, 3-position or 4-position.

  The compound represented by the formula (2) is preferably a compound represented by the following formula (2 ′).

R ^3, R ⁴ in the formula (2 '), m and n are each and R ^3, R ^4, m and n in Formula (2) synonymous, and preferred ranges are also the same.
In formula (2 ′), R ²¹ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group, and more preferably a hydrogen atom.
In formula (2 ′), each t independently represents an integer of 1 to 6, preferably an integer of 1 to 3, more preferably 1 or 2, and still more preferably 1. When t is 2 or more, a plurality of R ²¹ may be the same or different.
y ′ represents an integer of 2 to 4, preferably 2 or 3, and more preferably 2.
Y ² represents a residue obtained by removing a hydrogen atom of y ′ hydroxy groups from a polyhydroxy compound having at least y ′ hydroxy groups, and all (y ′ groups) are obtained from polyhydroxy compounds having y ′ hydroxy groups. It is preferably a residue obtained by removing a hydrogen atom from a hydroxy group. Specifically, a residue obtained by removing hydrogen atoms of y ′ hydroxy groups from a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, glycerin, trimethylolpropane, ditrimethylolpropane and pentaerythritol. It is preferably a group, and is preferably a residue obtained by removing all hydrogen atoms from a hydroxy group.
In formula (2 ′), A ² represents a group selected from the group consisting of the following formulas (i) to (iii).

(In Formula (i) to Formula (iii), any one of R ¹² and R ¹³ represents a hydrogen atom, the other represents a hydrogen atom, a methyl group, or an ethyl group, a represents an integer of 1 or 2, b represents an integer of 4 or 5, and z represents an integer of 1 to 20. In addition, * represents a bonding position with the carbonyl carbon, and ** represents a bonding position with Y ^2. )

A ² is preferably a group represented by the formula (i), and * — (OCH ₂ CH ₂ ) _z — **, * — (OCH ₂ CH ₂ CH ₂ CH ₂ ) _z — **, or , * —O (CH (CH ₃ ) CH ₂ ) _z — ** is more preferable. In this case, z is more preferably an integer of 3 to 10.

The molecular weight of the compound represented by the formula (2) is preferably 500 to 3,000, more preferably 800 to 2,500, and still more preferably 1,000 to 2,000.
When the molecular weight is 500 or more, elution of the compound from the cured film is suppressed, and an ink composition in which migration, odor, and blocking are suppressed is obtained. On the other hand, when it is 3,000 or less, the steric hindrance of the molecule is small, the degree of freedom of the molecule in the liquid / film is maintained, and high sensitivity is obtained.
In addition, when the compound represented by Formula (2) is a mixture of a plurality of compounds having different carbon numbers and the like, the weight average molecular weight is preferably in the above range.

  Specific examples of the compound represented by formula (2) are shown below, but the present invention is not limited to the following compounds.

  As the compound represented by the formula (2), a commercially available compound can also be used. Specifically, OMNIPOL BP (Polybutyleneglycol bis (4-benzoylphenoxy) acetate, CAS No. 515136-48-8) is exemplified.

  The compound represented by the formula (2) can be produced by a known reaction and is not particularly limited. For example, the compound represented by the above formula (2 ′) is represented by the following formula (2-1): It can prepare by making the compound represented and the compound represented by following formula (2-2) react.

R ³ , R ⁴ , R ²¹ , A ² , Y ² , m, n, t, and y ′ in formula (2-1) and formula (2-2) are R ³ , R ⁴ , R ²¹ , A ² , Y ² , m, n, t and y ′ have the same meanings, and the preferred ranges are also the same.
The above reaction is preferably performed in the presence of a solvent, and examples of suitable solvents include aromatic hydrocarbons such as benzene, toluene, and xylene.
The catalyst is preferably used in the presence of a catalyst. Examples of the catalyst include sulfonic acid (eg, p-toluenesulfonic acid, methanesulfonic acid), inorganic acid (eg, sulfuric acid, hydrochloric acid, phosphoric acid), Lewis acid (aluminum chloride, three Examples thereof include boron fluoride and organotitanate.
The reaction temperature and reaction time are not particularly limited.

  After completion of the reaction, the product can be separated by isolation from the reaction mixture by known means, washing as necessary and drying.

The content of the compound represented by the formula (2) is preferably 1 to 5% by mass of the entire ink composition from the viewpoint of increasing sensitivity and suppressing migration, odor and blocking, and 2 to 4%. More preferably, it is mass%.
Moreover, as a compound represented by Formula (2), the compound represented by Formula (2-1) is more preferable.

  The content of the compound represented by the formula (1) or the formula (2) is preferably 0.01 to 10% by mass, and preferably 0.05 to 8.0% by mass with respect to the entire ink composition. More preferably, it is more preferably 0.1 to 5.0% by mass, and particularly preferably 0.1 to 2.4% by mass. Within the above range, the curability is excellent.

In addition, the composition (I), the composition (II) and the composition (III) function as sensitizers as polymerization initiators because they absorb specific active energy rays and promote decomposition of the polymerization initiators. It is preferable to contain a compound (hereinafter also simply referred to as “sensitizer”).
Examples of the sensitizer include polynuclear aromatics (eg, pyrene, perylene, triphenylene, 2-ethyl-9,10-dimethoxyanthracene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, Rose Bengal etc.), cyanines (eg thiacarbocyanine, oxacarbocyanine etc.), merocyanines (eg merocyanine, carbomerocyanine etc.), thiazines (eg thionine, methylene blue, toluidine blue etc.), acridines (eg , Acridine orange, chloroflavin, acriflavine, etc.), anthraquinones (eg, anthraquinone, etc.), squaliums (eg, squalium), coumarins (eg, 7-diethylamino-4-methylcoumarin, etc.), thioxanthate Class (e.g., isopropyl thioxanthone), thiochromanone compound (e.g., a thiochromanone etc.) and the like.
Especially, as a sensitizer, thioxanthone is preferable and isopropyl thioxanthone is more preferable.
Moreover, a sensitizer may be used individually by 1 type and may use 2 or more types together.

  The total content of the polymerization initiator is preferably 1.0 to 15.0% by mass of each of the compositions (I), (II) and (III). More preferably, it is 5-10.0 mass%, and it is still more preferable that it is 3.0-8.0 mass%. It is excellent in curability as it is the said range.

<Colorant>
In the present invention, the ink composition (III) preferably contains a colorant in order to improve the visibility of the formed image portion.
The undercoat composition (I) and the undercoat composition (II) that can be used in the present invention may contain a colorant, but as described above, may contain a white colorant or not. Preferably it is not contained.
Although there is no restriction | limiting in particular as a coloring agent, The pigment and oil-soluble dye which were excellent in weather resistance and were rich in color reproducibility are preferable, and it can select and use arbitrarily from well-known coloring agents, such as a soluble dye. As the colorant, it is preferable to select a compound that does not function as a polymerization inhibitor from the viewpoint of not reducing the sensitivity of the curing reaction by actinic radiation.

Although it does not necessarily limit as a pigment which can be used for this invention, For example, the organic or inorganic pigment of the following number described in a color index can be used.
Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 42, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, 53. : 1, 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144 , 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13, 16, 20, 36, blue or cyan pigments include Pigment Blue 1,15,15: 1,15: 2,15: 3,15: 4,15: 6,16,1 -1, 22, 27, 28, 29, 36, 60, Pigment Green 7, 26, 36, 50 as a green pigment, and Pigment Yellow 1, 3, 12, 13, 14, 17, 34 as a yellow pigment , 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 120, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180 185, 193, Pigment Black 7, 28, 26 as the black pigment, and Pigment White 6, 18, 21, etc. as the white pigment according to the purpose.
In the present invention, a disperse dye can be used as long as it is soluble in a water-immiscible organic solvent. The disperse dye generally includes a water-soluble dye, but in the present invention, the disperse dye is preferably used as long as it is soluble in a water-immiscible organic solvent.
Preferable specific examples of the disperse dye include C.I. I. Disperse Yellow 5,42,54,64,79,82,83,93,99,100,119,122,124,126,160,184: 1,186,198,199,201,204,224 and 237 C. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54, 55, 66, 73, 118, 119 and 163; I. Disperse Red 54, 60, 72, 73, 86, 88, 91, 92, 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167: 1,177 , 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165: 1, 165: 2, 176, 183, 185, 197, 198, 201, 214, 224, 225 , 257, 266, 267, 287, 354, 358, 365 and 368; I. Disperse Green 6: 1 and 9;

  It is preferable that the colorant is appropriately dispersed in the ink composition (III) after being added to the ink composition (III). For dispersing the colorant, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, or a paint shaker can be used.

The colorant may be directly added together with each component when preparing the ink composition (III). Further, in order to improve dispersibility, it may be added to a dispersion medium such as a solvent or a polymerizable compound used in the present invention in advance and uniformly dispersed or dissolved, and then blended.
In the present invention, in order to avoid the deterioration of solvent resistance when the solvent remains in the cured image and the problem of VOC (Volatile Organic Compound) of the remaining solvent, the colorant is polymerizable. It is preferable to add and mix in advance in a dispersion medium such as a compound. In consideration of only dispersibility, it is preferable to select a monomer having a low viscosity as the polymerizable compound used for adding the colorant. One or more colorants may be appropriately selected and used depending on the intended use of the ink composition (III).

When using a colorant such as a pigment that remains solid in the ink composition (III), the average particle diameter of the colorant particles is preferably 0.005 to 0.5 μm, more preferably 0. It is preferable to set the colorant, the dispersant, the dispersion medium, the dispersion conditions, and the filtration conditions so as to be 0.01 to 0.45 μm, more preferably 0.015 to 0.4 μm. This particle size control is preferable because clogging of the head nozzle can be suppressed and the storage stability, transparency and curing sensitivity of the ink composition (III) can be maintained.
The content of the colorant in the ink composition (III) is appropriately selected depending on the color and purpose of use, but is preferably 0.01 to 30% by mass with respect to the mass of the entire ink composition.
In addition, when the undercoat composition (I) or the undercoat composition (II) contains a colorant, the content of the colorant in the composition is appropriately selected depending on the color and the purpose of use. It is preferable that it is 0.01-30 mass% with respect to mass.

<Dispersant>
In the present invention, the ink composition (III) preferably contains a dispersant. In particular, when a pigment is used, a dispersant is preferably contained in order to stably disperse the pigment in the ink composition.
Moreover, undercoat composition (I) and undercoat composition (II) used for this invention may contain a dispersing agent.
As the dispersant, a polymer dispersant is preferable. The “polymer dispersing agent” in the present invention means a dispersing agent having a weight average molecular weight of 1,000 or more.

Examples of the polymer dispersant include DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-111, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-166, and DISPERBYK-166. , DISPERBYK-168, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-182 (manufactured by BYK Chemie); EFKA7462, EFKA7500, EFKA7570, EFKA7575, EFKA7580 (manufactured by Efka Additive); Disperse Aid 6, Disperse Aid 8, Disperse Aid 15, Disperse Aid 9100 (manufactured by Sannopco); Solsperse (SOLSPERSE) 3000 Various Solsperse dispersants (manufactured by Noveon) such as 5000, 9000, 12000, 13240, 13940, 17000, 22000, 24000, 26000, 28000, 32000, 36000, 39000, 41000, 71000; Adeka Pluronic L31, F38, L42, L44 , L61, L64, F68, L72, P95, F77, P84, F87, P94, L101, P103, F108, L121, -123 (manufactured by ADEKA Co., Ltd.), Ionette S-20 (manufactured by Sanyo Chemical Industries, Ltd.); Disparon KS-860, 873SN, 874 (polymer dispersant), # 2150 (aliphatic polycarboxylic acid), # 7004 (polyether ester type) (manufactured by Enomoto Kasei Co., Ltd.).
The content of the dispersant in the undercoat composition (I), the undercoat composition (II) or the ink composition (III) is appropriately selected depending on the purpose of use, but is 0.05 to It is preferable that it is 15 mass%.

<Surfactant>
A surfactant may be added to the undercoat composition (I), the undercoat composition (II), or the ink composition (III) in order to provide stable ejection properties for a long time.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. Moreover, you may use a fluorine-type surfactant (for example, organic fluoro compound etc.) and silicone type surfactant (for example, polysiloxane compound etc.) as said surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compound include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826.

The polysiloxane compound is preferably a modified polysiloxane compound in which an organic group is introduced into a part of the methyl group of dimethylpolysiloxane. Examples of modification include polyether modification, methylstyrene modification, alcohol modification, alkyl modification, aralkyl modification, fatty acid ester modification, epoxy modification, amine modification, amino modification, mercapto modification, etc. is not. These modification methods may be used in combination. Of these, polyether-modified polysiloxane compounds are preferred from the viewpoint of improving ejection stability in inkjet.
Examples of the polyether-modified polysiloxane compound include, for example, SILWET L-7604, SILWET L-7607N, SILWET FZ-2104, SILWET FZ-2161 (manufactured by Nihon Unicar Co., Ltd.), BYK306, BYK307, BYK331, BYK333, BYK347. , BYK348 and the like (manufactured by BYK Chemie), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, Examples thereof include KF-6020, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (manufactured by Shin-Etsu Chemical Co., Ltd.).
Among these, a silicone-based surfactant is preferably used as the surfactant.
The content of the surfactant in the undercoat composition (I), the undercoat composition (II) or the ink composition (III) is appropriately selected depending on the purpose of use, but is 0.0001 to the mass of the entire composition. It is preferably 5% by mass, and more preferably 0.001 to 2% by mass.

In the present invention, when the amount of surfactant contained in the undercoat composition (II) is Q _II mass% and the amount of surfactant contained in the undercoat composition (I) is Q _I mass%, the following formula (Y) It is preferable to satisfy.
1 <Q _II / Q _I ≦ 15 (Y)
When Q _II / Q _I is within the above range, wetting and spreading of the undercoat composition (II) on the undercoat layer (1) formed by the undercoat composition (I) is good, and the occurrence of repelling is more Since it is suppressed, it is preferable.
Q _II / Q _I is more preferably 2 to 13, further preferably 5 to 13, and particularly preferably 8 to 12.

<Other ingredients>
In the present invention, the undercoating composition (I), the undercoating composition (II), and the ink composition (III) may include a co-sensitizer, an ultraviolet absorber, an antioxidant, It may contain an antifading agent, conductive salts, a solvent, a polymer compound, a basic compound, and the like. As these other components, known components can be used, for example, those described in JP-A-2009-22214.

The undercoat composition (I), the undercoat composition (II) or the ink composition (III) preferably contains a polymerization inhibitor from the viewpoints of storage stability and suppression of head clogging.
The content of the polymerization inhibitor is preferably 200 to 20,000 ppm with respect to the total mass of the composition.
Examples of the polymerization inhibitor include nitroso polymerization inhibitors, hindered amine polymerization inhibitors, hydroquinone, benzoquinone, p-methoxyphenol, TEMPO, TEMPOL, and cuperon Al.

<Physical Properties of Undercoat Composition (I), Undercoat Composition (II), and Ink Composition (III)>
In the present invention, it is preferable to use the ink composition (III) having a viscosity at 25 ° C. of 40 mPa · s or less in consideration of dischargeability. More preferably, it is 5-40 mPa * s, More preferably, it is 7-30 mPa * s. Moreover, it is preferable that the viscosity in discharge temperature (Preferably 25-80 degreeC, More preferably, 25-50 degreeC) is 3-15 mPa * s, and it is more preferable that it is 3-13 mPa * s. The composition ratio of the ink composition (III) is preferably adjusted appropriately so that the viscosity is in the above range. By setting the viscosity at room temperature (25 ° C.) high, even when a porous recording medium (support) is used, the penetration of the ink composition (III) into the recording medium is avoided, and the uncured monomer Can be reduced. Further, it is preferable because ink bleeding at the time of landing of the ink composition (III) droplets can be suppressed, and as a result, the image quality is improved.

  When the undercoat layer (2) is produced by inkjet, the viscosity at 25 ° C. of the undercoat composition (II) is preferably 40 mPa · s or less, more preferably 5 to 40 mPa · s, more preferably in consideration of dischargeability. Is 7 to 30 mPa · s. Moreover, it is preferable that the viscosity in discharge temperature (Preferably 25-80 degreeC, More preferably, 25-50 degreeC) is 3-15 mPa * s, and it is more preferable that it is 3-13 mPa * s. It is preferable that the composition ratio of the undercoat composition (II) is appropriately adjusted so that the viscosity is in the above range. By setting the viscosity at room temperature (25 ° C.) high, even when a porous recording medium (support) is used, the penetration of the undercoat composition (II) into the recording medium is avoided, and the uncured monomer Can be reduced.

The viscosity of the undercoat composition (I) is preferably 2,000 mPa · s or less at 25 ° C., more preferably 10 to 1,800 mPa · sec, from the viewpoint of uniform application to the recording medium, More preferably, it is 100-1500 mPa * s.
The viscosity of said composition (I), composition (II), and composition (III) is measured using an E-type viscosity meter (made by Toki Sangyo Co., Ltd.).

  The surface tension of the ink composition (III) at 25 ° C. is preferably 20 mN / m or more and 40 mN / m or less, more preferably 20.5 mN / m or more and 35.0 mN / m or less, and 21 mN / m. It is more preferably 30.0 mN / m or less, particularly preferably 21.5 mN / m or more and 28.0 mN / m or less. When the content is in the above range, a printed matter having excellent blocking resistance can be obtained.

In the present invention, when the surface tension at 25 ° C. of the undercoat composition (II) is P _II (mN / m) and the surface tension at 25 ° C. of the undercoat composition (I) is P _I (mN / m), It is preferable to satisfy the formula (X).
1 ≦ P _I −P _II ≦ 15 (X)
It is preferable that the surface tension of the undercoat composition (I) and the surface tension of the undercoat composition (II) satisfy the above relationship because the occurrence of repelling is further improved. When the relationship of the formula (X) is satisfied, the wetting spread of the undercoat composition (II) on the undercoat layer (1) formed by the undercoat composition (I) becomes good, and streak-like image defects are eliminated. It is estimated that the occurrence is suppressed.
(P _I -P _II ) is more preferably 2 to 14 (mN / m), further preferably 4 to 12 (mN / m), and 5 to 10 (mN / m). Is particularly preferred.

The surface tension of the undercoat composition (II) at 25 ° C. is preferably 15 mN / m to 40 mN / m, more preferably 20 mN / m to 35 mN / m, and 20 mN / m to 30 mN / m. More preferably.
Further, the surface tension of the undercoat composition (I) at 25 ° C. is preferably 15 mN / m to 40 mN / m, more preferably 20 mN / m to 35 mN / m, and 20 mN / m to 30 mN / m. More preferably.
In addition, as a method for measuring the surface tension of the composition (I), the composition (II) or the composition (III) at 25 ° C., a known method can be used, but the suspension ring method or the Wilhelmy method is used. It is preferable to measure. For example, a method of measuring using an automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. or a method of measuring using SIGMA 702 manufactured by KSV INSTRUMENTS LTD is preferred.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples.
In the following description, “parts” means “parts by mass” unless otherwise specified.

The materials used in the present invention are as shown below.
<Colorant>
・ IRGALITE BLUE GLVO (Cyan pigment, manufactured by BASF Japan)
・ CINQUASIA MAGENTA RT-355-D (magenta pigment, manufactured by BASF Japan)
・ NOVOPERM YELLOW H2G (yellow pigment, manufactured by Clariant)
SPECIAL BLACK 250 (black pigment, manufactured by BASF Japan)
・ Taipeku CR60-2 (white pigment, manufactured by Ishihara Sangyo Co., Ltd.)

<Dispersant>
・ SOLSPERSE32000 (Noveon dispersant)

<Polymerizable compound>
SR341: 3-methyl-1,5-pentanediol diacrylate (Sartomer)
SR344: Polyethylene glycol (400) diacrylate (manufactured by Sartomer)
PEA: Phenoxyethyl acrylate (SR339, manufactured by Sartomer)
CTFA: cyclic trimethylolpropane formal acrylate (SR531, manufactured by Sartomer)
SR9003: propoxylation (2) neopentyl glycol diacrylate

<Polymerization initiator>
IRGACURE 819 (bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, manufactured by BASF, molecular weight 419)
Speedcure 7010 (Compound IB described above, manufactured by Lambson, molecular weight 1,899)

<Acrylate oligomer>
CN147 (polyester acrylate oligomer, manufactured by Sartomer, viscosity (25 ° C.): 0.2 Pa · s or more, weight average molecular weight ≦ 20,000)
CN146 (polyester acrylate oligomer, manufactured by Sartomer, viscosity (25 ° C.): 1.2 Pa · s or more, weight average molecular weight ≦ 20,000)
CN820 (polyester acrylate oligomer, manufactured by Sartomer, viscosity (25 ° C.): 1.2 Pa · s or more, weight average molecular weight ≦ 20,000)
CN991 (urethane acrylate oligomer, manufactured by Sartomer, viscosity (25 ° C.): 1.2 Pa · s or more, weight average molecular weight ≦ 20,000)
CN2922 (urethane acrylate oligomer, manufactured by Sartomer, viscosity (25 ° C., 1.2 Pa · s or more, weight average molecular weight ≦ 20,000)

<Polymerization inhibitor>
UV-12 (FLORSTAB UV12, nitroso polymerization inhibitor, tris (N-nitroso-N-phenylhydroxylamine) aluminum salt, manufactured by Kromachem)

<Surfactant>
BYK-307 (silicone surfactant (polyether-modified polydimethylsiloxane), manufactured by BYK Chemie)
BYK-333 (silicone surfactant (polyether-modified polydimethylsiloxane), manufactured by BYK Chemie)

(Preparation of each mill base)
<Preparation of cyan mill base A>
300 parts by mass of IRGALITE BLUE GLVO, 620 parts by mass of SR9003, and 80 parts by mass of SOLPERSE32000 were mixed with stirring to obtain cyan mill base A. Cyan mill base A was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 4 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

<Preparation of magentavir base B, yellow mill base C, black mill base D and white mill base E>
Magenta mill base B, yellow mill base C, black mill base D and white mill base E were prepared in the same manner as cyan mill base A with the composition and dispersion conditions shown in Table 1.

<Preparation of Composition (I), Composition (II), and Composition (III)>
Each material was stirred and mixed at room temperature (25 ° C.) at 5,000 rpm for 20 minutes using a mixer (Silverson L4R) at the ratios shown in Tables 2 to 4, and Examples 1 to 15 and Comparison Composition (I), composition (II) and composition (III) used in Examples 1 to 6 were respectively prepared. In addition, the unit of content of each component in Tables 2-4 is a mass part. Moreover, description of "-" in a table | surface means that the said component is not contained.

<Image Forming Method 1>
As shown in FIG. 1, a roller coating machine is disposed at the most upstream part of the roll conveyance system, a nitrogen purge LED light source downstream thereof, a composition (II) head (clearing head), an LED light source downstream thereof, A black head, an LED light source, a cyan head, an LED light source, a magenta head, an LED light source, a W head, and a nitrogen purge LED exposure machine were arranged.
As the inkjet head, CA3 heads manufactured by TOSHIBA TEC CO., LTD. Were arranged in parallel for each color, and the heads were heated to 45 ° C., and the frequency was controlled so that drawing was possible with a droplet ejection size of 42 pL. As a light source, an LED light source unit having a peak wavelength of 385 nm (LEDZero Solidcure, manufactured by Integration Technology) is placed in an inert gas blanket, and an N ₂ gas generator with compressor, Maxi-Flow30 (manufactured by Inhouse Gas) is used as an inert gas source. ) At a pressure of 0.2 MPa · s, and N ₂ is flowed at a flow rate of ₂ to 10 L / min so that the N ₂ concentration in the blanket is in the range described in Tables 2 to 4, and the N ₂ concentration is Set. As the support (base material, recording medium), OPP (stretched polypropylene) 25 μm, PET 12 μm, and nylon 15 μm were used.
Scanning was performed at a speed of 30 m / min to draw a 100% solid image, and various performance tests shown below were performed.
In addition, the light quantity of the LED light source was adjusted so that composition (II) and each composition (III) (colored ink composition) could be maintained in a semi-cured state.
In Examples 16 and 17, the compositions (I) and (II) were formed in the same manner as in Example 1. For composition (III), the composition (III) of Example 1 was printed. The composition (III) of Example 12 was printed, and then the composition (III) of Example 13 was printed.

In Comparative Examples 3 and 5, the exposure amount with respect to the composition (I) was set to 400 W / cm ² to be in a semi-cured state. Moreover, in Comparative Example 6, the exposure amount for the composition (II) was set to 4,000 W / cm ² to obtain a completely cured state. In the pinning light source of the composition (III), the exposure amount was 400 W / cm ² . The exposure conditions described in Tables 2 to 4 are the exposure conditions for the last complete curing.
Whether the film was completely cured or semi-cured was determined by extracting a sample after exposure and performing a transfer test.
Specifically, plain paper (Fuji Xerox) is applied to the semi-cured undercoat composition or semi-cured ink composition on the extracted recording medium (PET) with a uniform force (500 to 1,000 mN / cm ² ). Co., Ltd. copy paper C2, product code V436) was pressed and allowed to stand for about 1 minute. After that, the plain paper was gently peeled off. A case where no transfer was observed was regarded as a completely cured state. The uncured state means a state in which no ultraviolet irradiation is performed.
As a result, all the compositions irradiated with 400 W / cm ² were in a semi-cured state, and all the compositions irradiated with 4,000 W / cm ² were in a completely cured state.

<Migration evaluation method>
10 mL of a water: ethanol = 70: 30 mixed solution was dropped onto the surface of the printed material, and the entire printed material was placed in a glass sealed container so that the mixed solvent would not volatilize, and left at 40 ° C. for 10 days. Thereafter, the total elution amount from the film (overall migration amount: OML) contained in the water and ethanol mixed solution was calculated and evaluated in 1 to 5 stages. The total volume was measured by allowing the aqueous ethanol mixture to volatilize after standing for 10 days and measuring the mass of the remaining components.
5: Elution amount is 50 ppb or less 4: Elution amount exceeds 50 ppb, 200 ppb or less 3: Elution amount exceeds 200 ppb, 1,000 ppb or less 2: Elution amount exceeds 1,000 ppb, 2,000 ppb or less 1: Elution amount If the evaluation exceeds 2,000 ppb and is 3 or more, there is no practical problem.

<Repelling evaluation method>
A solid image of 5 cm × 15 cm was printed on a PET substrate, and was evaluated visually from the occurrence frequency of streaks based on the following evaluation criteria.
4: No streak is observed 3: 1 or 2 streaks are observed 2: 3 or 4 streaks are observed 1: 5 or more streaks are observed Practical if the evaluation is 2 or more There is no problem.

<Smudge evaluation method>
As shown in FIG. 2, a 1 mm blank is provided around a 1 cm × 1 cm solid image on a PET substrate, and a green solid is printed around the blank with the yellow ink of Example 13 and the cyan ink of Example 1. The degree of bleeding was visually observed by printing an image (stipple portion in the figure).
Evaluation was performed based on the following criteria.
Among 5 images printed and observed,
No blurring is observed in 3: 1 sheets. Bleeding is observed in 2: 1 or 2 sheets. 1: Bleeding is observed in 3 or more sheets. If the evaluation is 2 or more, there is no practical problem.

<Odor evaluation method>
The image (21 cm × 29.7 cm) on the PET substrate obtained by the inkjet image recording method was enclosed in a plastic bag with a zip of 30 cm × 30 cm and left for 24 hours.
Thereafter, the zip was released and the odor was evaluated. The evaluation was made by rounding off the average value of 10 people.
5: Almost odorless 4: Slight odor but little concern 3: Some odor but not unpleasant level 2: Strong odor 1: Very strong odor Evaluation is 3 or more If there is, there is no practical problem.

<Evaluation of adhesion (tape peeling)>
A tape peel test was performed on the image obtained by the inkjet image recording method. The tape peeling test of each base material of OPP, PET, and nylon was performed.
3: No peeling at all.
2: The peeling of the entire area of the image is 20% or less 1: The peeling of the entire area of the image exceeds 20% If the evaluation is 2 or more, there is no practical problem.

  12: recording medium, 14: primer composition (I) coating roller, 15, 22: nitrogen purge exposure light source unit, 16: means for applying primer composition (II), 17: primer composition (II) semi-curing exposure Light source, 18K, 18C, 18M, 18Y, 18W: inkjet head, 20K, 20C, 20M, 20Y: semi-curing exposure light source, 24: delivery roller, 26: take-up roller, 28: nip roll

Claims (11)

(Step a) preparing a recording medium having an undercoat layer (1) obtained by completely curing the undercoat composition (I);
(Step b) A step of applying the undercoat composition (II) onto the undercoat layer (1) and irradiating the applied undercoat composition (II) with an actinic ray to semi-cure,
(Step c) A step of discharging the ink composition (III) onto the semi-cured undercoat composition (II), and
(Step d) including a step of irradiating the undercoat composition (II) and the ink composition (III) with actinic rays to cure the whole in this order,
Undercoat composition (I), undercoat composition (II), and ink composition (III) each contain (Component A) a radically polymerizable compound and (Component B) a polymerization initiator,
The undercoat composition (II) and the ink composition (III) each contain a polyfunctional ethylenically unsaturated compound as component A in an amount of 60% by mass or more of each composition,
The undercoat composition (I) contains an acrylate oligomer as component A,
Inkjet recording method.   The ink jet recording method according to claim 1, wherein the undercoat composition (I) contains an acrylate oligomer in an amount of 60% by mass or more of the composition. When the surface tension of the undercoat composition (II) at 25 ° C. is P _II (mN / m) and the surface tension of the undercoat composition (I) at 25 ° C. is P _I (mN / m), the following formula (X) The inkjet recording method according to claim 1 or 2, wherein
1 ≦ P _I −P _II ≦ 15 (X) When the amount of surfactant contained in the undercoat composition (II) is Q _II mass% and the amount of surfactant contained in the undercoat composition (I) is Q _I mass%, the following formula (Y) is satisfied: Item 4. The inkjet recording method according to any one of Items 1 to 3.
1 <Q _II / Q _I ≦ 15 (Y)   The inkjet recording method according to claim 1, wherein step d is a step of irradiating active rays at an oxygen partial pressure of 0.15 atm or less.   The ink jet recording according to any one of claims 1 to 5, wherein the undercoat composition (I), the undercoat composition (II), and the ink composition (III) contain an acylphosphine oxide compound as the component B. Method.   The inkjet recording method according to any one of claims 1 to 6, wherein the actinic rays in the steps b and d are actinic rays irradiated by the LED.   The inkjet recording method according to any one of claims 1 to 7, wherein the undercoat composition (II) and the ink composition (III) contain an alkylene glycol diacrylate as the component A. The ink jet recording method according to any one of claims 1 to 8, wherein the ink composition (III) contains a compound represented by the following formula (1) and / or formula (2) as the component B.

(In Formula (1) and Formula (2), R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, and x and y are each independently Each represents an integer of 2 to 4, j and m each independently represents an integer of 0 to 4, k and n each independently represents an integer of 0 to 3, and j, k, m and n are When it is an integer of 2 or more, a plurality of R ¹ , R ² , R ³ and R ⁴ may be the same or different, and X ¹ includes at least ^one of a hydrocarbon chain, an ether bond and an ester bond x And X ² represents a y-valent linking group containing at least one of a hydrocarbon chain, an ether bond, and an ester bond.)   The inkjet recording method according to any one of claims 1 to 9, which is for package printing.   The recording medium according to claim 1, wherein the recording medium is a resin film having a film thickness of 10 μm or more and 90 μm or less and containing at least one component selected from the group consisting of polyethylene terephthalate, polyethylene, polypropylene, and nylon. The inkjet recording method according to any one of the above.