JP6000215B2 - 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 problems to be solved by the present invention include an inkjet recording method capable of obtaining a printed matter in which migration from a cured image is suppressed, ink bleeding is suppressed, odor is low, and excellent adhesion is obtained, and printed matter Is to provide.

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) formed of the aqueous latex composition (I), (Step b) an 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 (II), and The ink composition (III) contains (component A) a radically polymerizable compound and (component B) a polymerization initiator, respectively, an ink jet recording method,
<2> The inkjet recording method according to <1>, wherein the aqueous latex composition (I) contains a resin selected from the group consisting of a urethane resin, a polyester resin, and an acrylic ester resin.
<3> The inkjet recording method according to <1> or <2>, wherein the aqueous latex composition (I) contains a compound that reacts with a carboxylic acid,
<4> Any one of <1> to <3>, wherein the undercoat composition (II) and the ink composition (III) contain a bifunctional (meth) acrylate compound as component A in an amount of 60% by mass or more of the entire composition. An ink jet recording method according to claim 1;
<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> The ink jet recording method according to any one of <1> to <5>, wherein the undercoat composition (II) and the ink composition (III) contain an acylphosphine oxide compound as Component B.
<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 inkjet recording method 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): ,

(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. ~ Inkjet recording method according to any one of <10>,
<12> Printed matter obtained by the inkjet recording method according to any one of <1> to <11>.

  According to the present invention, there are provided an ink jet recording method capable of obtaining a printed material in which migration from a cured image is suppressed, ink bleeding is suppressed, odor is low, and adhesion is excellent, and a printed material. I was able to.

<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>.

(Inkjet recording method)
The inkjet recording method of the present invention provides a recording medium having an undercoat layer (1) formed of (step a) an aqueous latex composition (I) (hereinafter also simply referred to as “composition (I)”). 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 a step (d) of irradiating the undercoat composition (II) and the ink composition (III) with actinic rays to cure the whole, in this order. (II) and ink composition (III) are respectively (component A) radical polymerizable. And compound, characterized by containing the (Component B) a polymerization initiator.
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 is insufficient when an image is formed by a conventional ink jet recording method in food packaging package printing for soft packaging.
The present inventor has intensively studied and found that the adhesion is improved by providing an image layer on the undercoat layer (1) formed of the aqueous latex composition (I). When an image is directly formed with the ink composition (III) on the undercoat layer (1) formed with the composition (I), sufficient adhesion to the substrate can be obtained, but there is a new problem that bleeding occurs. occured.
The inventor forms a semi-cured layer with the undercoat composition (II) on the undercoat layer (1) formed with the aqueous latex composition (I), and further the ink composition (III) thereon. Thus, the inventors have found that by forming an image, an image having excellent adhesion to the substrate and further suppressing bleeding can be obtained, and the present invention has been completed.
In addition, it is preferable that the composition (II) and the composition (III) contain 60% by mass or more of a polyfunctional ethylenically unsaturated compound with respect to the whole composition, thereby reducing odor and suppressing migration. It is estimated that a printed matter can be obtained.

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) formed from an aqueous latex composition (I) The ink jet recording method of the present invention comprises an undercoat layer formed from an aqueous latex composition (I) ( Including a step of preparing a recording medium having 1).
The aqueous latex composition (I) is obtained by dispersing a dispersoid mainly composed of a polymer compound (resin) in an aqueous dispersion medium (solvent).
A preferred embodiment of the aqueous latex 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. The 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) formed of the aqueous latex 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 aqueous latex composition (I) on the recording medium,
(Step a ² ) A step of removing the solvent from the applied aqueous latex composition (I) to form the undercoat layer (1) (hereinafter also referred to as “solvent removal step” or “drying step”).
In the present invention, after performing the above steps a ¹ and step a ^2, a series of steps, the step b and step it it is more preferable to perform or c.

(Step a ¹ ) Step of applying aqueous latex composition (I) on recording medium In the ink jet recording method of the present invention, as means for applying aqueous latex composition (I) on a recording medium, a coating device or an ink jet nozzle 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 aqueous latex composition (I) onto the recording medium is preferably performed using a relatively inexpensive bar coater, reverse roll coater, transfer roll coater, or gravure coater.

The aqueous latex 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 an area wider than the image, and the entire area where the image can be formed. It is preferable that it is provided so as to cover.
The applied amount (mass per unit area) of the aqueous latex composition (I) is preferably 0.05 to 5 g / m ² as the mass after drying (solvent removal), and 0.06 to 3 g / m. ² is more preferable. It is preferable that the application amount of the aqueous latex composition (I) is within the above range since a sufficient adhesion improving effect can be obtained and a printed matter having excellent flexibility can be obtained.
In addition, after drying means after removing the volatile component (solvent) containing water from the coating layer.

(Step a ² ) Step of removing the solvent from the applied aqueous latex composition (I) to form the undercoat layer (1) The method of removing the solvent from the aqueous latex composition (I) is an aqueous latex composition If the solvent containing water which (I) contains can be removed, it will not specifically limit, A well-known method can be used.
Specific examples include natural drying, heat drying (IR (infrared heating) drying, induction heating drying), ventilation drying, warm air drying (hot air drying), vacuum drying, and microwave drying. Moreover, you may use combining these drying methods. Among these, heat drying is preferable from the viewpoint of productivity and cost.
As described above, 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. Therefore, from the viewpoint of suppressing deformation and shrinkage of the recording medium due to heat, the heating temperature is preferably 100 ° C. or less, more preferably 30 to 80 ° C., and still more preferably 35 to 75 ° C. 40 to 70 ° C. is particularly preferable.

(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. 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, a semi-curing step (hereinafter also referred to as a 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 (1) formed from aqueous latex composition (I). 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 ink composition (III) discharged on the undercoat composition (II) or the undercoat liquid composition (II) applied on the undercoat layer (1) is semi-cured, the degree of curing is not uniform. There may be. For example, the undercoating composition (II) and / or the ink composition (III) is preferably cured in the depth direction. In addition, the case where active rays, such as an ultraviolet-ray, is not irradiated is made into an uncured state.

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 ink compositions for ultraviolet curable ink jet recording. Yes. 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. If 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 formed in 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 an image forming step).
By ejecting the ink composition (III) onto the undercoating composition (II) in a semi-cured state, the printed matter obtained is excellent in image quality and flexibility.

  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, any of the ink compositions is preferably in direct contact with each other or discharged onto the semi-cured undercoat composition (III) 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.

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 (Fuji Xerox Co., Ltd., copy paper C2, product code V436) is pressed with a uniform force (500 to 1,000 mN / cm ² ) and left to stand for about 1 minute. After that, when the plain paper is gently peeled off, no transfer is recognized at all, and the completely cured state is obtained.

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. If 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 0.1 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 0.1 atm or less, (a) the atmosphere at the time of exposure is reduced. It can be achieved by setting the pressure to 0.47 atm or less, or (b) mixing a gas other than air and oxygen (for example, an inert gas such as nitrogen or argon) in an amount of 53 vol% or more with respect to the 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 preferably 0.10 atm or less, more 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 by the inert gas replacement is preferably controlled to 0.01 to 10% by volume (at this time, the oxygen partial pressure is controlled to 0.0001 to 0.10 atm), and 0.1 to 0.1%. It is more preferable to control to 5% by volume.

  As a means for controlling the oxygen concentration in the curing atmosphere to 0.01% to 10%, 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.

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 inkjet recording apparatus of the present invention comprises a conveying means for conveying a recording medium, an applying means for applying an aqueous latex composition (I) on the recording medium, and an aqueous latex composition (I) applied on the recording medium. ) A drying means for removing the solvent from the solvent, an applying means for applying the undercoat composition (II) onto the undercoat layer (1) formed by the aqueous latex composition (I), and an applied undercoat composition (II) Semi-curing means for semi-curing, discharging means for ink-jetting the ink composition (III) onto the semi-cured undercoat composition (II), and the semi-cured undercoat liquid (II) and ink composition It is preferable to have a complete curing means for completely curing (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 feeding 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 aqueous latex composition (I) is applied by the application roller 14 with the aqueous latex composition ( I) is applied, and the solvent is removed from the aqueous latex composition (I) by exposing it to hot air at 60 ° C. for 1 minute by the dryer 15 which is a drying means of the aqueous latex composition (I). Next, the undercoat composition (II) is applied onto the undercoat layer (1) formed by the aqueous latex 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 unit 22, for example, an LED light source is surrounded by an inert gas blanket and connected to an inert gas generator via an inert gas pipe, and the inert gas generator is operated. An embodiment in which the air in the blanket is replaced with an inert gas is preferred. 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. Since the undercoat layer is formed of the aqueous latex composition (I), the ink jet recording method of the present invention enables the use of nip rolls, realizes more accurate transportability, and shifts in registration (shifts in landing positions). ) Is suppressed. The nip roll 28 is not essential, and an image forming apparatus that does not have a nip roll may be used.

(Aqueous latex composition (I), undercoat composition (II), and ink composition (III))
Aqueous latex composition (I) (composition (I)), undercoat composition (II) (composition (II)), and ink composition (III) (ink) used in the inkjet recording method of the present invention The composition or the composition (III)) will be described. In the present invention, the composition (I) is an aqueous latex composition, the composition (II) and the composition (III) comprise (component A) a radical polymerizable compound and (component B) a polymerization initiator. contains.

The composition (II) and the 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.

<Aqueous latex composition (I)>
In the present invention, the aqueous latex composition (I) is obtained by dispersing a dispersoid mainly composed of a polymer compound (resin) in an aqueous dispersion medium (solvent). That is, it refers to a resin layer in which a resin is emulsified and suspended as a solid phase in a liquid layer containing water as a main solvent and can be dried to form a film.
The aqueous dispersion medium contains 50% by mass or more of water, and in addition, a mixture to which a water-miscible organic solvent is optionally added can be used. Water-miscible organic solvents include alcohols (eg, methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyhydric alcohols (E.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), glycol derivatives (e.g., Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl Ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether , Triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amine (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine) , Triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl- 2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone).
Examples of water-miscible organic solvents used in combination with methanol include methanol, ethanol, n-butanol, isopropanol, t-butyl cellosolve (ethylene glycol mono t-butyl ether), and n-butyl cellosolve (ethylene glycol mono n-butyl ether), and isopropyl Alcohol, t-butyl cellosolve, and n-butyl cellosolve are preferred.
Two or more kinds of the water-miscible organic solvents may be used in combination.
The content of the organic solvent in the dispersion medium is preferably 20% by mass or less, more preferably 10% by mass or less, and most preferably not contained.

In the present invention, the aqueous dispersion medium of the aqueous latex composition (I) contains 50% by mass or more of water, preferably 60% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass. More preferably, it is contained more preferably 90% by mass or more, and most preferably 100% by mass.
As water, pure water, distilled water, ion-exchanged water, or the like can be used.

Next, the polymer (resin) contained in the aqueous latex composition (I) as a dispersoid will be described.
The resin component is not particularly limited as long as it can form a film by drying, but from the viewpoint of improving adhesion, it is a resin selected from the group consisting of urethane resin, polyester resin, and acrylic ester resin. Is preferred. Since the compatibility with the base material is high, it is presumed that the effect of improving the adhesion is high.

As urethane resin, HYDRAN series (for example, HYDRAN AP10, AP20, AP30, AP40, APX-101H, 1320NS, 1610NS, 1670NS, 1980NS, HW-337, HW-350, HW-920, manufactured by Dainippon Ink and Chemicals, Inc. , HW-940), Taisei Fine Chemical Co., Ltd. Acryt series (Acryt WEM-202U, WEM-3008, WEM-321U, WEM-031U, WBR-016U, WBR-2018U, WBR-2019), Daiichi Seika ( Co., Ltd. Rezamin series (Rezamin D-1000, D-2000, D-4000, D-6000, D-9000), Takamatsu Yushi Co., Ltd. NS-155NX, NS-310A, NS-310X, NS-311X , Nippon Polyurethane Co., Ltd. Ltd. WOE-305, and the like Elastron manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. (all trade names).
As various polyester resins, various plus coats manufactured by Tateo Chemical Industry Co., Ltd., various types of byronals manufactured by Toyobo Co., Ltd. (for example, Byronal MD-1200, MD-1245, MD-1500), Byron (for example, Byron 200), Examples include Finetex ES series manufactured by Dainippon Ink and Chemicals, KP series manufactured by Matsumoto Yushi Seiyaku Co., Ltd., and Pes Resin A series manufactured by Takamatsu Yushi Co., Ltd.
Torisei Co., Ltd. Jurimer AT series, Jurimer ET series, Dainippon Ink & Chemicals Co., Ltd. Finetex 6161, K-96, Voncoat series, Seiko Chemical Industry Co., Ltd. high loss series (for example, acrylic ester resin) Hyros NL-1189, BH-997L), Daicel Chemical Industries Co., Ltd. Sebian series, Nippon Zeon Co., Ltd. Nipol series, JSR Co., Ltd. AE series, Toagosei Co., Ltd. Aron series, Takamatsu Yushi ( NS series manufactured by Nissin Chemical Industry Co., Ltd., and ViniBran series manufactured by Nissin Chemical Industry Co., Ltd. (all are trade names).

The acid value of the resin is preferably 0.1 mgKOH / g or more, more preferably 1 to 60 mgKOH / g, still more preferably 2 to 60 mgKOH / g, and 2 to 40 mgKOH / g. It is particularly preferred.
When the acid value of the resin is within the above range, high adhesion can be obtained by cross-linking when used in combination with a cross-linking agent described later, and the amount of cross-linking agent required is appropriate.

  The Tg of the resin is preferably −50 to 65 ° C., more preferably −50 to 55 ° C., and still more preferably −50 to 45 ° C. It is preferable for the resin to have a Tg within the above range because the film-forming property is excellent and the adhesion is good.

The resin preferably has a weight average molecular weight of 1,000 or more. More preferably, it is 2,000-100,000, and still more preferably 5,000-100,000.
When the weight average molecular weight is within the above range, transfer is difficult when a roll is formed, which is preferable.

The aqueous latex composition (I) preferably contains 10 to 60% by mass of the resin, more preferably 20 to 50% by mass, and particularly preferably 20 to 40% by mass of the entire latex composition. .
It is preferable for the content of the resin to be in the above range because the dispersion state in the composition is excellent and the dispersion medium can be easily removed.

In this invention, aqueous latex composition (I) may contain components other than the above, and specifically, a crosslinking agent is illustrated.
By containing a crosslinking agent, the hardness of the resulting undercoat layer (1) is improved, and the adhesion is improved, which is preferable.
The cross-linking agent is preferably reactive with the functional group on the surface of the resin or substrate. For example, the cross-linking agent is preferably a compound that reacts with a carboxylic acid (carboxy group), a hydroxyl group, or the like. More preferably, the compound reacts with the group.
Examples of the compound that reacts with the carboxylic acid include oxazoline compounds and carbodiimide compounds.
Moreover, an isocyanate compound is illustrated as a compound which reacts with a hydroxyl group.
In addition, the molecular weight of the said crosslinking agent is not specifically limited, A high molecular compound may be sufficient and a low molecular compound may be sufficient.

The oxazoline compound is not particularly limited as long as it is a compound having an oxazoline group. Oxazoline groups react with carboxy groups and thiol groups to form crosslinks. In particular, it reacts with a carboxy group at a relatively low temperature to form an amide ester as a crosslinked structure. The reaction is characterized by the absence of by-products.
Specific examples of the oxazoline compound include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2 -Isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2,2'-bis- (2-oxazoline), 2,2'-methylene-bis- (2- Oxazoline), 2,2′-ethylene-bis- (2-oxazoline), 2,2′-trimethylene-bis- (2-oxazoline), 2,2′-tetramethylene-bis- (2-oxazoline), 2 2'-hexamethylene-bis- (2-oxazoline), 2,2'-octamethylene-bis- (2-oxazoline), 2,2'-ethylene-bis- (4,4'-dimethyl) -2-oxazoline), 2,2'-p-phenylene-bis- (2-oxazoline), 2,2'-m-phenylene-bis- (2-oxazoline), 2,2'-m-phenylene- Bis- (4,4′-dimethyl-2-oxazoline), bis- (2-oxazolinylcyclohexane) sulfide, bis- (2-oxazolinylnorbornane) sulfide and the like can be mentioned. Furthermore, (co) polymers of these compounds are also preferably used.
Further, as the oxazoline compound, Epocros K2010E, K2020E, K2030E, WS-500, WS-700 (manufactured by Nippon Shokubai Chemical Co., Ltd.) and the like can be used.

As the carbodiimide compound, those having a cyclic structure are also preferable. This is because the carboxylic acid and the cyclic carbodiimide undergo a ring-opening reaction, the other of the ring-opening reaction with the carboxylic acid reacts with another carboxylic acid to increase the molecular weight, and thus the generation of isocyanate gas is suppressed. is there.
Specific examples of the carbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, 1,5-naphthalenecarbodiimide, 4,4′-diphenylmethanecarbodiimide, 4,4′-diphenyldimethylmethanecarbodiimide, and JP2011-153209A. There are carbodiimides having the cyclic structure described.
As the carbodiimide compound, for example, Carbodilite V-02, Carbodilite V-02-L2, Carbodilite V-04, Carbodilite E-01, Carbodilite E-02 (manufactured by Nisshinbo Industries, Inc.) can be used.

  In this invention, it is preferable that content of a crosslinking agent is 5-200 mass% with respect to latex resin, It is more preferable that it is 8-150 mass%, It is further that it is 10-120 mass%. preferable. It is preferable from a viewpoint of adhesion improvement that content of a crosslinking agent is in the above-mentioned range.

  In addition to the above components, the aqueous latex composition (I) may contain a surfactant, a dispersant, a thickener, a water retention agent, an antifoaming agent, a water resistance agent, a colorant, and the like. The surfactant will be described later.

(Undercoat composition (II) and ink composition (III))
The undercoat composition (II) and the ink composition (III) each contain (Component A) a radical polymerizable compound and (Component B) a polymerization initiator.

<(Component A) radical polymerizable compound>
In the present invention, each of 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.

[Polyfunctional ethylenically unsaturated compound]
The undercoat composition (II) and the ink composition (III) each preferably contain a polyfunctional ethylenically unsaturated compound, and more preferably 60% by mass or more based on the total mass of the composition. When the content of the polyfunctional ethylenically unsaturated compound is 60% by mass or more, the occurrence of migration and odor is suppressed.
The content of the polyfunctional ethylenically unsaturated compound in the undercoat composition (II) and the ink composition (III) is more preferably 70 to 98% by mass, and particularly preferably 75 to 97% by mass.

In the present invention, the undercoat composition (II) and the ink composition (III) preferably contain a polyfunctional (meth) acrylate compound as a polyfunctional ethylenically unsaturated compound. More preferably, it contains a bifunctional acrylate compound, more preferably a diacrylate monomer.
In the present invention, the undercoat composition (II) and the ink composition (III) preferably contain 60% by mass or more of a bifunctional (meth) acrylate compound, more preferably 70 to 98% by mass, and 75 It is especially preferable to contain -97 mass%.
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.

  Specifically, as other bifunctional (meth) acrylate compounds, dipropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide (EO) modified neo Pentyl 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) Preferred are acrylate and triethylene glycol di (meth) acrylate.

  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 undercoat composition (II) and the ink 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 the polyalkylene glycol diacrylate, that is, the repeating number of the alkyleneoxy group is 2 or more, preferably 2 to 100, and more preferably 2 to 20.
The content of polyalkylene glycol diacrylate in the undercoat composition (II) and the ink composition (III) is preferably 1 to 50% by mass, and 2 to 40% by mass, based on the total mass of the composition. It is more preferable, and it is still more preferable that 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 (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 ether ) Acrylate, dipropylene glycol (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, oligopropylene oxide monoalkyl ether (meth) acrylate, 2-methacryloyloxytyl succinic acid, 2-methacryloyloxyhexahydrophthalic 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 nonylphenol (meta Acrylate, propylene oxide (PO) modified nonylphenol (meth) acrylate, EO modified-2-ethylhexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) Examples include 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 (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 (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 the present invention may be used alone or in combination of two or more.
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.

  As preferable examples of the acylphosphine compound, 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- Dipentyloxyphenylphos Oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,6-dimethylbenzoylethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine 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-pentyloxy) Phenyl) phenylphosphine 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 ink composition (III) preferably contains at least a compound represented by the following formula (1) or (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, undercoat 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 in the formula (2-1) and formula ^{(2-2), R 4, R} 21, A 2, Y 2, m, n, t and y 'formula (2' R ³ in), R ⁴ , R ²¹ , A ² , Y ² , m, n, t and y ′, respectively, 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.

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 (II) and the composition (III), as a polymerization initiator, absorb a specific active energy ray and promote the decomposition of the polymerization initiator. It is also preferable to contain a “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 the entire composition (II) and composition (III), and 1.5 to 10.0% by mass. % Is more preferable, and 3.0 to 8.0 mass% is still more preferable. 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 aqueous latex composition (I) and the undercoat composition (II) that can be used in the present invention may contain a colorant but, as described above, may or may not contain a white colorant. Is preferable, and it is more preferable not to contain.
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.
Further, when the aqueous latex 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% of the total solid content of thing (I). The total solid content means the total mass excluding volatile components such as a solvent containing water. Moreover, it is preferable that it is 0.01-30 mass% with respect to the whole mass of undercoat composition (II).

<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, the aqueous latex composition (I) and the undercoat composition (II) used in the present invention may contain a dispersant.
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 aqueous latex 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 the mass of the entire composition. It is preferably ˜15% by mass.

<Surfactant>
A surfactant may be added to the aqueous latex 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, as the surfactant contained in the undercoat composition (II) and the ink composition (III), a silicone-based surfactant is preferably exemplified.

In addition, the aqueous latex composition (I) preferably contains a nonionic surfactant as a surfactant. Polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene Examples include polyoxypropylene block copolymers, polyoxyethylene alkyl esters, polyoxyethylene alkyl allyl esters, sorbitol and sorbitan fatty acid esters, pentaerythritol fatty acid ester, and the like.
Among these, polyoxyethylene alkyl ether is preferable because it has an excellent function as an emulsifier. Polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene Preferred examples include poly (oxyethylene) alkyl ethers having an alkyl group having 12 or more carbon atoms, such as oleyl ether. The alkyl group may be linear or branched.

  The content of the surfactant is appropriately selected depending on the purpose of use, but is preferably 0.0001 to 5% by mass, and 0.001 to 2% by mass with respect to the mass of the entire solid content of the composition. Is more preferable.

<Other ingredients>
In the present invention, the undercoat composition (II) and the ink composition (III) may contain, in addition to the above-described components, a co-sensitizer, an ultraviolet absorber, an antioxidant, an anti-fading agent, and conductive salts, if necessary. , 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 (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 Aqueous Latex 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 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. 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 aqueous latex composition (I) is preferably 500 mPa · s or less at 25 ° C., more preferably 200 mPa · sec or less, and 100 mPa · sec or less from the viewpoint of uniform application to the recording medium. More preferably.
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.

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.
In addition, as a measuring method of the surface tension at 25 degreeC of composition (II) or composition (III), although a well-known method can be used, it is preferable to measure by the suspension ring method or the Wilhelmy method. 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)
CTFA: cyclic trimethylolpropane triacrylate (SR531, manufactured by Sartomer)
SR344: Polyethylene glycol (400) diacrylate (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)
Vinylchloro-acetate (prepared by the method described in Example 22 of JP-T-2008-520623)

<Resin (latex)>
-WBR016U (Acrit WBR-016U, polyether urethane emulsion, Taisei Fine Chemical Co., Ltd., solid content concentration: 26% by mass)
・ Plus coat Z-592 (water-soluble polyester resin, Kyoyo Chemical Co., Ltd., solid content concentration: 25% by mass)
・ Jurimer ET-410 (acrylic emulsion, Toagosei Co., Ltd., solid content concentration: 30% by mass)
<Crosslinking agent>
Epocross K-2020E (Oxazoline group-containing emulsion, manufactured by Nippon Shokubai Co., Ltd., solid content concentration: 39% by mass)
Carbodilite V-02-L2 (Cross-linking agent for carbodiimide-based aqueous resin, manufactured by Nisshinbo Co., Ltd., solid content concentration: 40% by mass)

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

<Surfactant>
・ Emulgen 109P (polyoxyethylene lauryl ether (ether type nonionic surfactant), manufactured by Kao Corporation)
BYK-307 (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 5,000 rpm at room temperature (25 ° C.) for 20 minutes using a mixer (Silverson L4R) at the ratio shown in Table 2, Examples 1 to 14 and Comparative Examples 1 to 1. Composition (I), composition (II) and composition (III) used in 4 were 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 coater is disposed at the most upstream part of the roll conveyance system, and is dried by exposure to hot air at 60 ° C. for 1 minute downstream thereof, and further a head for the composition (II) (clear) Head), LED light source, black head, LED light source, cyan head, LED light source, magenta head, LED light source, W head, nitrogen purge LED exposure machine. The aqueous latex composition (I) was applied to the substrate so as to be 1.0 g / m ² after drying.
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 with a peak of 385 nm (LEDZero Solidcure, manufactured by Integration Technology) is placed in an inert gas blanket, and an N ₂ gas generator with a compressor Maxi-Flow30 (Inhouse Gas, Inc.) is used as an inert gas source. Made 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 shown in Table 2, and the N ₂ concentration is set did. As a support (base material, recording medium), OPP (stretched polypropylene, thickness: 25 μm, manufactured by Futamura Chemical Co., Ltd., FOR-AQ), PET (thickness: 12 μm, manufactured by Futamura Chemical Co., Ltd., FE2001), Nylon (thickness: 15 μm, manufactured by Unitika Ltd., ON) was 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 9 and 10, compositions (I) and (II) were formed in the same manner as in Example 2. For composition (III), composition (III) of Example 2 was printed. The composition (III) of Example 5 was printed, and then the composition (III) of Example 6 was printed.

<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.

<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.

<Adhesion (tape peeling) evaluation method>
A tape peel test was performed on the image obtained by the inkjet image recording method. A tape peel test of the PET substrate was performed.
3: No peeling at all 2: Peeling of the entire area of the image is 20% or less 1: Peeling of the entire area of the image exceeds 20% If the evaluation is 2 or more, there is no practical problem.

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

Claims (11)

(Step a) preparing a recording medium having an undercoat layer (1) formed from the aqueous latex 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,
The undercoat composition (II) and the ink composition (III) each contain (Component A) a radical polymerizable compound and (Component B) a polymerization initiator.
Inkjet recording method.   The inkjet recording method according to claim 1, wherein the aqueous latex composition (I) contains a resin selected from the group consisting of a urethane resin, a polyester resin, and an acrylic ester resin.   The inkjet recording method according to claim 1 or 2, wherein the aqueous latex composition (I) contains a compound that reacts with a carboxylic acid.   The undercoat composition (II) and the ink composition (III) contain a bifunctional (meth) acrylate compound as component A in an amount of 60% by mass or more based on the total composition. Inkjet recording method.   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 inkjet recording method according to claim 1, wherein the undercoat composition (II) and the ink composition (III) contain an acylphosphine oxide compound as Component B.   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).

(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.