JP2022057729A - Ink set, and method for producing laminate - Google Patents

Abstract

To provide an ink set capable of producing a laminate excellent in coatability of an underlayer while having no image defect, and excellent in stability with time in printing by simultaneously discharging a plurality of liquid compositions.SOLUTION: An ink set has a first liquid composition, and a second liquid composition, and satisfies the following relational expressions a) and b) when forming a second liquid droplet layer by making liquid droplets composed of the second liquid composition having a diameter of 200 μm or less strike on a first liquid layer composed of the first liquid composition. a) AE/AM≥0.9 where AM(μm2) is a maximum cross-sectional area of the second liquid droplet layer, and AE(μm2) is an exposed cross-sectional area of the second liquid droplet layer at any time of a time after two seconds and a time after 10 seconds from strike. b) -0.2≤(AM_0.2-AM_30)/AM_0.2≤0.2 where AM_0.2(μm2) and AM_30(μm2) are maximum cross-sectional areas after 0.2 second and 30 seconds from strike of the second liquid droplet layer.SELECTED DRAWING: None

Description

The present invention relates to a method for manufacturing an ink set and a laminate.

In recent years, active energy ray-curable inks have been widely used for offsets, silk screens, topcoat agents, etc., but they have advantages such as cost reduction by simplifying the drying process and reduction of solvent volatilization as an environmental measure. , The amount used is increasing. Recently, the number of industrial applications for decorative printing and coating using inkjet is increasing from the viewpoint of on-demand performance.

Generally, when the same color is reproduced on a transparent base material and a colored base material (wood, metal, etc.) regardless of the base material, for example, two layers of a white base layer and a color layer for drawing are formed. There are methods and so on. In addition, as inkjet suitability, there is generally a trade-off relationship between coating film fastness and adhesion, and ink coating films alone often do not meet market demands, so it is necessary to separately coat or laminate. However, since these are separate processes, productivity is reduced. It is also possible to maintain productivity by providing an in-line inkjet base layer forming process, drawing process, and coating process, but a large device that connects the processes corresponding to each layer is required, and a small inkjet machine is required. Cannot be adapted to.

On the other hand, if an inkjet device such as a serial printer is used alone to form multiple layers, each layer needs to be printed, which significantly reduces the production speed. Therefore, instead of printing each layer individually, if the base layer and the upper layer for coating or drawing can be formed into multiple layers by batch ejection in one step without disturbing the laminated state, the functions can be separated in each layer. , Productivity can be greatly improved.
Normally, even if inks having different functions are simply ejected all at once, a layer cannot be formed, which causes problems such as image distortion. Therefore, in order to solve the above-mentioned problems, for example, the second liquid composition (liquid B) is subjected to an inkjet method on the liquid surface of the first active energy ray-curable liquid composition (liquid A) according to a target periodic signal. ) Is discharged, and then the liquid A and the liquid B are irradiated with active energy rays to be cured, and a method for producing a film having a periodic pattern is proposed. For example, see Patent Document 1).

It is an object of the present invention to provide an ink set which is excellent in the covering property of the lower layer and is excellent in the time-dependent stability of an image immediately after ejection in printing in which a plurality of liquid compositions are simultaneously ejected, and can prevent image defects.

The ink set of the present invention as a means for solving the above-mentioned problems has a first liquid composition and a second liquid composition, and is on a first liquid layer composed of the first liquid composition. When a droplet having a diameter of 200 μm or less composed of the second liquid composition is landed to form a second droplet layer, the following relational expressions a) and b) are satisfied.
a) At any time within 10 seconds from 2 seconds after landing, the maximum cross-sectional area of the second droplet layer on the plane parallel to the first liquid layer is _AM (μm ² ), the first. When the cross-sectional area of the second droplet layer exposed on one liquid layer is _AE (μm ² ),
A _E / _AM ≧ 0.9
b) The maximum cross-sectional area 0.2 seconds after the impact of the second droplet layer on the plane parallel to the first liquid layer is _{AM_0.2} (μm ² ) and the second droplet. When the maximum cross-sectional area 30 seconds after the landing of the layer is _{AM_30} (μm ² ),
-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2

According to the present invention, in printing in which a plurality of liquid compositions are simultaneously ejected, it is possible to provide an ink set which is excellent in the covering property of the lower layer, is excellent in the stability of an image immediately after ejection with time, and can prevent image defects.

FIG. 1 is a schematic view showing an example of a laminated body manufacturing apparatus according to the present invention. FIG. 2 is a schematic view showing a state of formation of a laminated body using the apparatus for producing a laminated body in the present invention. FIG. 3 is a diagram showing an example of a color image used for calculating the maximum cross-sectional area _AM of the second droplet layer. FIG. 4 is a diagram showing an example of a laser image used for calculating the exposed cross-sectional area _AE of the second droplet layer. FIG. 5 is a diagram showing an example of a color image showing a corresponding portion of the maximum cross-sectional area _AM of the second droplet layer. FIG. 6 is a diagram showing an example of a laser image showing a corresponding portion of the exposed cross-sectional area _AE of the second droplet layer. FIG. 7 is a schematic cross-sectional view showing the position of the maximum cross-sectional area _AM of the second droplet layer in the laminated body of the present invention. FIG. 8 is a schematic cross-sectional view showing the position of the exposed cross-sectional area _AE of the second droplet layer in the laminated body of the present invention.

(Ink set)
The ink set of the present invention has at least a first liquid composition and a second liquid composition, and further has a plurality of second liquid compositions, other liquid compositions, and the like, if necessary. May be good.
The ink set formed a second droplet layer by landing a droplet having a diameter of 200 μm or less made of the second liquid composition on the first liquid layer made of the first liquid composition. In this case, the following relational expressions a) and b) are satisfied.
a) At any time within 10 seconds from 2 seconds after landing, the maximum cross-sectional area of the second droplet layer on the plane parallel to the first liquid layer is _AM (μm ² ), the first. When the cross-sectional area of the second droplet layer exposed on one liquid layer is _AE (μm ² ),
A _E / _AM ≧ 0.9
b) The maximum cross-sectional area 0.2 seconds after the impact of the second droplet layer on the plane parallel to the first liquid layer is _{AM_0.2} (μm ² ), and the second droplet layer. When the maximum cross-sectional area 30 seconds after landing is _{AM_30} (μm ² ),
-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2

The ink set of the present invention is based on the fact that the present inventors have found the following problems in the prior art. That is, the film manufacturing method of the prior art document (Japanese Unexamined Patent Publication No. 2011-23501) has a problem that a thin film having a low dot density can be manufactured with high accuracy, but the spreading method of the ink to be landed cannot be controlled. Normally, when forming a layer, it is necessary to land the upper layer ink on the lower layer ink in a floating state and with a large dot diameter. When the spread of ink dots cannot be controlled, when the dot diameter is large, the ink dots continue to spread in a short time after landing until they dry or cure, the image area of the upper layer ink changes, and the image blurs. There is a problem that image defects such as low density occur. On the other hand, when the dot diameter is reduced so that the ink dots do not spread in the floating state, there is a problem that the lower layer surface cannot be covered and the lower layer surface is exposed and the color development property is deteriorated. Therefore, when the landing ink is floated to have a large dot diameter for layer formation, it is important to control the spread of the ink dots.

Further, in the prior art, when the same color is reproduced on a transparent base material and a colored base material (wood, metal, etc.) regardless of the base material, a white base layer is formed and then a color layer for drawing is formed. There is a problem that the productivity is significantly lowered because the layer needs to be formed in another process. When the image is carried out by batch ejection, there is a problem that the layer formation does not go well and the image is distorted and the color development property cannot be obtained. In order to obtain color development, it is necessary to cover the white base layer with the drawing color layer, but when covering the white base layer, the ink of the drawing color layer that lands on the white base layer floats. It is necessary to form a state and a large dot diameter. It is possible to land while floating on the surface of the lower layer and to form a large dot diameter at the time of landing, but the dot diameter will change in a short time after forming a large dot diameter at the time of landing and then curing. It becomes difficult to control because it keeps expanding. As a result, the dot diameter of the landed color layer for drawing continues to expand on the white base layer until it dries and cures, and as a result, the density changes and the size of the image change depending on the time until it cures. Therefore, there is a problem that image defects such as distortion of the formed image occur.

In the ink set of the present invention, when the step of ejecting the first droplet composed of the first liquid composition and the step of ejecting the second droplet composed of the second liquid composition are simultaneously performed, the first step is performed. A second droplet of the second liquid composition floats on the first liquid layer of the first liquid composition (relational formula a). Therefore, layer formation (that is, production of a laminated body) becomes possible. Further, the second droplet made of the second liquid composition forms large dots having a size capable of covering the surface of the first liquid layer on the first liquid layer made of the first liquid composition. , Maintain the dot area without continuing to spread (relational formula b). Therefore, when the second liquid composition is a color ink having a pigment, a laminate having high color development and sharpness can be obtained, and when the second liquid composition is a coating ink, the robustness is obtained. A high laminate is obtained.
Further, the laminated body can be manufactured without sandwiching the curing step between the steps. As a result, not only high productivity can be obtained, but also it can be used for a small inkjet device. In addition, since delamination is unlikely to occur, higher adhesion can be obtained than the laminate obtained by curing each layer. Since it is not necessary to consider the recoating property, it is possible to add surface products such as antifouling property and slipperiness.
Therefore, according to the method for producing an ink set and a laminate of the present invention, the lower layer surface can be covered in a layered state by printing in which a plurality of liquid compositions are simultaneously ejected, and the stability over time without causing image quality deterioration is achieved. It is possible to provide an ink set capable of manufacturing a certain laminate and a method for producing the laminate.

<Relational expressions a and b>
The ink set formed a second droplet layer by landing a droplet having a diameter of 200 μm or less made of the second liquid composition on the first liquid layer made of the first liquid composition. In this case, the following relational expressions a) and b) are satisfied.
Relational expression a) A _E / _AM ≧ 0.9
Relational expression b) -0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2

<Relational expression a>
Relational expression a) A _E / _AM ≧ 0.9
In the formula, the maximum cross-sectional area _AM (μm ² ) indicates the maximum cross-sectional area of the second droplet layer.
The exposed cross-sectional area _AM (μm ² ) indicates the cross-sectional area of the second droplet layer exposed on the first liquid layer.
The maximum cross-section area _AM and the exposed cross-section area _AM are values at any time from 2 seconds to 10 seconds after the impact of the droplet composed of the second liquid composition, for example. The maximum cross-sectional area _AM 2 seconds after the landing is referred to as " _{AM_2} ".
The "cross section" of the maximum cross-section _AM and the exposed cross-section _AM is a plane parallel to the first liquid layer (or the surface of the first liquid layer). As shown by the broken line in FIG. 7, the maximum cross-sectional area _AM of the second droplet layer 2 is on a plane parallel to the surface of the first liquid layer 1 in the cross section of the laminated body 10, and the cross-sectional area is large. It is the maximum. Further, as shown by the broken line in FIG. 8, the maximum cross-sectional area _AM of the second droplet layer 2 is on a plane parallel to the surface of the first liquid layer 1 in the cross section of the laminated body 10, and is the first. The cross-sectional area is the largest among the portions exposed on the first liquid layer 1 of the second droplet layer 2. Reference numeral 3 in FIGS. 7 to 8 indicates a recording medium.

The following equation, " _AE / _AM ", is 0.9 or more, preferably 0.95 or more, and more preferably 1.0.
When the following formula, " _AE / _AM " is 0.9 or more, the second droplet layer floats without diving into the first liquid layer composed of the first liquid composition to form dots. Since it spreads immediately after landing and maintains the dot shape over time, it is possible to continue to cover the first liquid layer. " _AE / _AM " represents the floating state of the landed droplet on the first liquid layer, so that the second droplet landing equal to 1 does not dive into the first liquid layer. Indicates a floating state.

<< Calculation of maximum cross-section area _AM and exposed cross-section area _AM >>
The maximum cross-section area _AM and the exposed cross-section area _AM can be calculated by the following procedure from a dot observation image of a laminate produced by printing 150 dpi × 150 dpi using one nozzle row (FIG. 3). , Figure 4). The maximum cross-sectional area _AM is the area surrounded by the solid line in FIG. 5 and the area surrounded by the broken line in FIG. 6, and the exposed cross-sectional area A _E is the area surrounded by the broken line in FIG. 5 and FIG. The area surrounded by the solid line.
A second liquid composition layer is formed by landing a droplet having a droplet diameter of 200 μm or less made of the second liquid composition on the first liquid layer made of the first liquid composition to form a laminated body. do. From the color images (FIGS. 3 and 5) of the obtained dot observation images of the laminated body, the first liquid composition was viewed from the discharge port of the laminated body manufacturing apparatus as the recording medium. The maximum cross-sectional area _AM of the second droplet layer in the horizontal direction with the surface of the liquid layer can be calculated (FIG. 5, the area surrounded by the solid line). Alternatively, the maximum dot diameter r _M of the second droplet layer can be calculated, and the maximum cross-sectional area _AM can be calculated by using the following calculation formula.
_{AM = ((r M /} 2) ^ 2) * 3.14

Among the obtained dot observation images of the laminated body, the laser image (FIGS. 4 and 6) shows the first liquid composition when the recording medium is viewed from the discharge port of the laminated body manufacturing apparatus. The exposed cross-sectional area _AE of the second droplet layer of the portion exposed on the first liquid layer in the horizontal direction with the liquid layer surface can be calculated (FIG. 6, the area surrounded by the solid line). Alternatively, the exposed cross-sectional area A _E can be calculated by calculating the exposed dot diameter r _E of the second droplet layer of the portion exposed on the first liquid layer and using the following calculation formula.
A _E = ((r _E / 2) ^ 2) * 3.14

The maximum cross-sectional area _AM and the exposed cross-sectional area _AM are MH5421 (Ricoh Co., Ltd.) as an inkjet head for an inkjet ejection device in which a plurality of inkjet heads and a UV light source are mounted on a series of carriages as shown in FIG. Manufactured by) can be obtained by printing at a frequency of 20 kHz and a carriage speed of 847 mm / s using a device equipped with a UV-LED light source having a wavelength of 395 nm as an active energy ray irradiation device. The specifications of the MH5420 are a laminated piezo push mode method, the number of nozzles is 1280 (320 × 4 rows), the nozzle pitch is about 0.1693 mm / row, and the maximum drive frequency is 30 kHz for single drop and 20 kHz for multi drop. As the recording medium, a base material that can be adsorbed on the pedestal, such as a polycarbonate base material (manufactured by Mitsubishi Gas Chemical Company, Inc.), can be used.

The maximum cross-sectional area _AM and the maximum dot diameter r _M represent the area and dot diameter of the entire landed second droplet when the laminate is viewed from the discharge port (FIGS. 5 and 7), and the exposed cross-sectional area A. _E and exposed dot diameter r _E represents the area and dot diameter of the portion exposed on the surface of the first liquid layer of the second droplet that has landed (FIGS. 6 and 8). The second droplet that has landed so that _AM and _AE are equal is in a state of floating on the first liquid layer, and the second droplet is submerged in the first liquid layer as _AE becomes smaller. Indicates the state.
The droplet is a minute droplet, that is, a droplet having a droplet diameter smaller than the capillary length and having a droplet diameter in which surface tension is dominant with respect to gravity. The capillary length l (mm) obtained from the ratio of gravity and surface tension serves as this index, and the surface tension γ (mN / m), the density ρ (g / cm ³ ), and the gravity acceleration g (m / s ² ) are used. The time when gravity and surface tension are balanced can be expressed by the following equation.
ρgl ³ = γl

When the capillary length is larger than the droplet diameter, gravity becomes dominant, and when the capillary length is smaller than the droplet diameter, surface tension becomes dominant. For example, when the length is reduced from the capillary length to 1/10, the contribution of gravity and tension becomes 1: 100, and the tension becomes dominant. The diameter of the droplets of the microdroplets is preferably 200 μm or less, in which the contribution of tension is large (approximately 2 mm) or less, and the contribution of tension is more dominant, and the surface tension is sufficiently dominant and inkjet is used. It is more preferably several tens of μm or less in that it can be discharged. When the droplet diameter is larger than the capillary length, the impact behavior changes according to the density of the liquid composition because it cannot be controlled by surface tension and gravity becomes dominant. It becomes difficult to control the landing behavior of the droplet. On the other hand, when the droplet diameter is 200 μm or less, the landing behavior can be controlled by the surface tension, so that the ink set of the present invention is established. The fine droplets can be ejected by, for example, an inkjet method.

<Relational expression b>
Relational expression b) -0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2
In the formula, the maximum cross-sectional area _{AM_0.2} (μm ² ) indicates the maximum cross-sectional area 0.2 seconds after the impact of the second droplet layer, and the maximum cross-sectional area _{AM_30} (μm ² ) is the second. The maximum cross-sectional area 30 seconds after the impact of the droplet layer is shown.

The following formula, "( _{AM_0.2} - _{AM_30} ) _{/AM_0.2} ", is preferably -0.2 or more and 0.2 or less, and more preferably -0.2 or more and 0 or less.
When "( _{AM_0.2} - _{AM_30} ) _{/AM_0.2} " is -0.2 or more and 0.2 or less, the second droplet landed on the first liquid layer immediately after landing. There is an advantage that the change in the maximum cross-sectional area of the second droplet layer due to spreading on the surface of the first liquid layer from to curing is small. When "( _{AM_0.2} - _{AM_30} ) _{/AM_0.2} " is -0.2 or more and 0 or less, the maximum cross-sectional area of the second droplet layer after landing does not expand and shrinks to dots. Since the force is generated, there is an advantage that image defects such as the image spreading due to the repulsion between the dots at high dot density and the image to be produced being disturbed and the color development property are deteriorated do not occur. For example, when a laminate is produced using a plurality of second liquid compositions having different colors, the laminate is produced without causing a problem that an image cannot be formed due to coalescence of different colors. Can be done.
At this time, the average thickness of the first liquid layer on which the second droplet lands is preferably 10 μm or more, and more than the radius of the droplet (more than half of the dot diameter _rM of the second droplet). preferable.

<Static surface tension>
When the static surface tension of the first liquid composition is γ _1S (mN / m) and the static surface tension of the second liquid composition is γ _2S (mN / m), the following equation, “γ”. " _1S -γ _2S " is preferably 0 or more and 5 or less, and more preferably 0 or more and 3 or less.
When "γ _1S −γ _2S " is 0 or more, the second liquid composition lands on the first liquid layer composed of the first liquid composition and then instantly appears on the surface of the first liquid layer without diving. There is an advantage that the image can be formed while floating on the surface. When "γ _1S −γ _2S " is 0 or more and 5 or less, the maximum cross-sectional area of the landed second droplet layer does not expand too much. Therefore, it is possible to prevent the maximum cross-sectional area (dot size) of the second droplet layer from expanding until the second droplet layer floating on the first liquid layer is cured. Therefore, it is possible to produce a laminated body without causing image defects. Further, when “γ _1S −γ _2S ” is 0 or more and 3 or less, the dot size can be maintained over time without the maximum cross-sectional area of the second droplet layer continuing to spread on the first liquid layer.

<Dynamic surface tension with a life time of 15 ms>
The dynamic surface tension of the first liquid composition having a lifetime of 15 ms is γ _{1D_15} (mN / m), and the dynamic surface tension of the second liquid composition having a lifetime of 15 ms is γ _{2D_15} (mN / m). Then, the following equation, “γ _{1D_15} −γ _{2D_15} ”, preferably exceeds 0, and more preferably more than 0 and 5 or less.
When "γ _{1D_15} -γ _{2D_15} " exceeds 0, the droplets of the second liquid composition landed on the first liquid layer of the first liquid composition can spread instantly after landing. A large dot diameter can be formed immediately after landing, and the surface of the first liquid layer can be covered with the second liquid composition.
From the relationship with static surface tension, when "γ _{1D_15} -γ _{2D_15} " exceeds 0 and "γ _1S -γ _2S " is 0 or more and 5 or less, the landing droplets do not dive into the lower layer and are the first. It floats on the liquid layer of the above to form a large dot diameter, and the dot size can be maintained without continuing to spread.
When "γ _{1D_15} -γ _{2D_15} " is more than 0 and 5 or less and "γ _1S -γ _2S " is 0 or more and 3 or less, the dot size after landing does not become too large, so that the dot density is high. At that time, the repulsion between dots is suppressed, and image defects do not occur.

<Dynamic surface tension with a life time of 1500 ms>
The dynamic surface tension of the first liquid composition having a lifetime of 1500 ms is γ _{1D_1500} (mN / m), and the dynamic surface tension of the second liquid composition having a lifetime of 1500 ms is γ _{2D_1500} (mN / m). Then, the following equation, “γ _{1D_1500} −γ _{2D_1500} ”, is preferably less than 0.
When "γ _{1D_1500} -γ _{2D_1500} " is less than 0, the force that the droplets try to spread after landing on the first liquid layer and forming the second droplet layer is suppressed immediately after landing. .. Therefore, a force acts on the second droplet layer formed on the first liquid layer in the direction of maintaining the shape or shrinking after forming a large dot diameter. As a result, since the dot diameter does not expand over time after landing, repulsion between ink dots can be suppressed, and a laminated body can be produced without causing image defects such as image area change and bleeding. Can be done.
On the other hand, when "γ _{1D_1500} −γ _{2D_1500} " is 0 or more, the size of the dots formed after landing increases with time, and the larger the value, the larger the spread of the dot diameter.
Further, in relation to the static surface tension, when "γ _{1D_1500} -γ _{2D_1500} " is 0 or more and "γ _1S -γ _2S " becomes positively large (for example, when it exceeds 5,), the second droplet is formed. Since the dot size of the layer expands greatly without stopping over time, it greatly affects image defects.

Here, the static surface tension and the dynamic surface tension of the curable liquid composition can be measured as follows.

-Static surface tension-
The static surface tension is measured at 25 ° C. using, for example, an automatic surface tension meter (DY-300, manufactured by Kyowa Surface Chemistry Co., Ltd.) and a platinum plate by the plate method.

-Dynamic surface tension-
For the dynamic surface tension, for example, a dynamic surface tension meter (DynoTest, manufactured by SITA) is used, and the dynamic surface tension at 150 msec is measured at 25 ° C.

When another liquid composition having a life time of 150 ms and a dynamic surface tension lower than that of the second liquid composition by 5 mN / m or more is used in place of the first liquid composition in the relational expression a). When the maximum cross-sectional area of the second droplet layer is A _MO (μm ² ), the following equation, “ _AM / A _MO ”, is preferably 1.9 or more.
That is, when a droplet having a diameter of 200 μm or less made of the second liquid composition is landed on the third liquid layer made of the other liquid composition to form the second liquid droplet layer, the first liquid composition is formed. When the maximum cross-sectional area of the second droplet layer on the plane parallel to the three liquid layers is A _MO (μm ² ), A _MO (μm ² ) and the second droplet with respect to the first liquid layer. The relationship between the maximum cross-sectional area of the layer and _AM (μm ² ) satisfies the following equation.
_AM / A _MO ≧ 1.9

Examples of the "other liquid composition" having a dynamic surface tension of 5 mN / m or more having a life time of 150 ms lower than that of the second liquid composition include a liquid composition containing silicone oil having a low surface tension. Be done. When such a liquid composition having a low surface tension is used as a lower layer instead of the first liquid composition, the second liquid composition lands so as to slip into the lower layer. At this time, the dot shape of the landing droplet maintains the droplet shape close to a sphere, and the maximum cross-sectional area _AMO of the second droplet layer is when it spreads on the surface of the lower layer ( _AM ). Small in comparison.
When " _AM / A _MO " is 1.9 or more, it indicates that the dot shape ( _AM ) of the landing droplet is not a droplet shape close to a sphere but floats and spreads on the surface of the lower layer. ing.
On the other hand, if " _AM / A _MO " is less than 1.9, the landed droplets may be submerged and cannot spread while floating on the lower layer surface. As a result, the second droplet cannot cover the surface of the first liquid composition, and the surface coverage is lowered, which leads to defects such as deterioration of color development.

The maximum cross-sectional area _AM (μm ² ) of the second droplet layer is preferably 3840 μm ² or more, preferably 3840 μm ² or more and 15390 μm ² or less when the droplet composed of the second liquid composition is 18 ng. Is more preferable. When the maximum cross-sectional area _AM is 3840 μm ² or more, the droplets landing on the first liquid layer made of the first liquid composition are in a state of floating on the surface of the first liquid layer and the second liquid. Form a drop layer. When the maximum cross-sectional area _AM is 15390 μm ² or less, an image can be formed without image defects due to repulsion between dots even when a laminated body is produced with a high dot density.
On the other hand, when the maximum cross-sectional area _AM is 15390 μm ² or more, the dot size of the second droplet layer is too large, and when a laminate is produced with a high dot density, the image spreads due to the repulsion between the dots. Therefore, it may not be possible to form an image, which may cause image defects.

The values of the maximum cross-sectional area _{AM, the exposed cross-sectional area A E ,} and the relational expressions a and b depend on the above-mentioned static surface tension difference, dynamic surface tension difference, and the type and amount of the surfactant described later. It can be controlled as appropriate.

<Liquid composition>
The first liquid composition and the second liquid composition (hereinafter, may be collectively referred to as “liquid composition”) are not particularly limited and may be appropriately selected depending on the intended purpose, for example. , Aqueous liquid compositions containing water as the main component, solvent-based liquid compositions mainly containing quick-drying organic solvents, active energy ray-curable liquid compositions that cure by irradiating active energy rays such as ultraviolet rays, etc. Can be mentioned. Among these, the active energy ray-curable liquid composition is preferable.
The first liquid composition and the second liquid composition are preferably inkjet inks in that a laminate is produced by batch ejection of a plurality of liquid compositions.

Usually, when a laminate is produced by batch ejection of a plurality of liquid compositions, the liquid composition exists in a liquid state until the liquid composition is fixed on the substrate, and the pigment, the dye and the like are fixed through a drying step or a curing step. In the case of an aqueous liquid composition containing water as a main component, water, which is the main component, evaporates during the drying step, so that convection in the layer occurs due to evaporation. Therefore, it may be difficult to control the layered structure formed in the liquid state at the time of fixing and to develop the targeted color development and functional separation. On the other hand, in the case of the active energy ray-curable liquid composition, since it is cured by irradiating it with active energy rays, it is cured on the substrate without being affected by the convection of the liquid composition formed in the layered structure. be able to. Therefore, it is more preferable that the ink set is an active energy ray-curable inkjet ink.

Further, it is preferable that the first liquid composition is a white ink or a clear ink, and the second liquid composition is a color ink or a clear ink. It is preferable that the second liquid composition can form a layer of color ink or clear ink on the first liquid layer.

The liquid composition contains a monomer and a surfactant, preferably a polymerization initiator and a coloring material, and further contains an organic solvent and other components, if necessary.

<< Monomer >>
The monomer is a compound that undergoes a polymerization reaction by an active species generated by heating or active energy rays (ultraviolet rays, electron beams, etc.) and is cured. Depending on the number of functional groups, a polyfunctional monomer or a monofunctional monomer may be used. Can be mentioned.
The monomer may be any polymerizable monomer and may contain a polymerizable oligomer or a polymerizable polymer (macromonomer).
The type of the monomer of each active energy ray-curable liquid composition is not particularly limited and may be appropriately selected depending on the intended purpose. However, since the first liquid composition is located in the lower layer of the laminate, it is therefore located in the lower layer of the laminate. It is preferable to impart the function of adhesion to form an adhesion layer, it is preferable to contain a large amount of monofunctional monomers, and it is more preferable to contain 80% by mass or more of monofunctional monomers.

-Monofunctional monomer-
The monofunctional monomer is a monomer having one functional group.
The monofunctional monomer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, hydroxyethyl (meth) acrylamide, (meth) acryloylfophorin, dimethylaminopropylacrylamide, isobornyl (meth) acrylate, etc. Adamanthyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 3,3,5 -Trimethylcyclohexane (meth) acrylate, t-butyl methacrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate , 2-Hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, phenoxyethyl acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, cyclic trimethylolpropaneformal acrylate, etc. Be done. These may be used alone or in combination of two or more.

-Polyfunctional monomer-
The polyfunctional monomer includes a bifunctional monomer, a trifunctional monomer, or a monomer having a higher number of functional groups.
The polyfunctional monomer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, neopentyl glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, diethylene glycol di (meth). Acrylate, Triethylene glycol di (meth) acrylate, Tetraethylene glycol di (meth) acrylate, (Poly) propylene glycol di (meth) acrylate, Dipropylene glycol di (meth) acrylate, (Poly) tetramethylene glycol di (meth) Acrylate, propylene oxide (PO) adduct of bisphenol A di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, ethylene oxide (EO) adduct of bisphenol A Di (meth) acrylate, EO-modified pentaerythritol trimethylolpropane (meth) acrylate, PO-modified pentaerythritol trimethylolpropane (meth) acrylate, EO-modified pentaerythritol tetra (meth) acrylate, PO-modified pentaerythritol tetra (meth) acrylate, EO-modified dipenta Elythritol tetra (meth) acrylate, PO-modified dimethylolethylene tetra (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO-modified trimethylolmethane tetra (meth) acrylate , PO-modified tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, trimethylolpropanetri (meth) acrylate, tetramethylolmethanetetra (Meta) acrylate, trimethylolethanetri (meth) acrylate, trimethylolpropane tri (meth) acrylate, bis (4- (meth) acryloxipolyethoxyphenyl) propane, diallylphthalate, triallyl trimellitate, 1,6 -Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl hydroxypivalate Glycoldi (meth) acrylice Acrylate, tetramethylol methanetri (meth) acrylate, dimethyloltricyclodecanedi (meth) acrylate, modified glycerintri (meth) acrylate, bisphenol A diglycidyl ether (meth) acrylic acid adduct, modified bisphenol A di (meth) ) Acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate tolylene diisocyanate urethane prepolymer, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate urethane prepolymer , Ditrimethylol propanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate urethane prepolymer, urethane acrylate oligomer, epoxy acrylate oligomer, polyester acrylate oligomer, polyether acrylate oligomer, silicone acrylate oligomer and the like. These may be used alone or in combination of two or more. Among these, the number of functional groups is preferably 2 to 6 functional, and the bifunctional monomer is particularly preferable from the viewpoint of low viscosity.

<< Surfactant >>
The surfactant is added in order to impart different liquid physical characteristics so that each liquid composition exhibits the above-mentioned landing behavior.
The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a fluorine-based surfactant, a polysiloxane-based surfactant, a silicone-based surfactant, an organic-based surfactant and the like can be selected. Can be mentioned.
Since the second droplet made of the second liquid composition has the property of floating and spreading on the first liquid layer made of the first liquid composition, the second liquid composition is the first one. The surfactant can be appropriately selected from the relationship with the surface tension with the liquid composition.
As the type of the surfactant in the second liquid composition, a surfactant having a high static surface tension lowering ability and a low dynamic surface tension lowering ability is preferable in terms of forming a uniform film, and such a surfactant is preferable. An amphoteric surfactant having a hydrophilic group and a lipophilic group is preferable because it has an action of weakening the surface tension. Examples of such a surfactant include a polysiloxane-based surfactant (for example, Twin 4000: an organically modified siloxane copolymer), a silicone-based surfactant (for example, Rad2500: a completely crosslinkable silicone acrylate), and the like.
The surfactant in the second liquid composition may be used alone or in combination of two or more, but it is preferable to use two different surfactants in combination.

The content of at least one of the surfactants in the second liquid composition is preferably 0.1% by mass or less, more preferably 0.001% by mass or more and 0.1% by mass or less, and more preferably 0.001. It is particularly preferable to use mass% or more and 0.01% by mass or less. By adding a small amount of a surfactant having a high static surface tension lowering ability to the second liquid composition in an amount of, for example, 0.001% by mass or more and 0.1% by mass or less, the amount of the surfactant is small, so that the landing occurs. As the droplets spread, the amount of the surfactant per unit area decreases and the surface tension increases, so that the surface tension of the first liquid composition can be balanced. That is, by adjusting the amount of the surfactant having a high ability to reduce the static surface tension, it is possible to design the dot to automatically stop expanding after the dots have expanded to some extent.
On the other hand, since the surfactant having no action of weakening the surface tension can be added without complying with the above content, the surfactant having the action of weakening the surface tension is added to the second liquid composition. If at least one of the above is contained, a design for stopping the dot expansion can be established.
The surfactant in the first liquid composition is not particularly limited and may be appropriately selected depending on the intended purpose.

The content of the surfactant in the liquid composition is not particularly limited and may be appropriately selected depending on the intended use and applicable means. For example, when the active energy ray-curable ink is ejected from the nozzle of the inkjet head. Is preferably not contained in a large amount of a surfactant, preferably less than 1% by mass, more preferably less than 0.5% by mass, and particularly preferably less than 0.1% by mass.

<< Polymerization Initiator >>
The liquid composition may contain a polymerization initiator. The polymerization initiator may be any one capable of generating active species such as radicals and cations by heat or energy of active energy rays and initiating the polymerization of the polymerizable compound (monomer or oligomer). As such a polymerization initiator, known radical polymerization initiators, cationic polymerization initiators, base generators and the like can be used alone or in combination of two or more. Among these, a radical polymerization initiator is preferable.
The radical polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose. For example, aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides and thio compounds. Examples thereof include (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, ketooxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, alkylamine compounds and the like.
The content of the polymerization initiator is preferably 5% by mass or more and 20% by mass or less with respect to the total amount of the liquid composition in order to obtain a sufficient curing rate.

In addition to the polymerization initiator, a polymerization accelerator (sensitizer) can also be used in combination. The polymerization accelerator is not particularly limited and may be appropriately selected depending on the intended purpose. For example, trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, p. Examples thereof include amine compounds such as -dimethylaminobenzoic acid-2-ethylhexyl, N, N-dimethylbenzylamine and 4,4'-bis (diethylamino) benzophenone.
The content of the polymerization accelerator is not particularly limited and can be appropriately set according to the polymerization initiator used and the amount thereof.

<< Color material >>
The liquid composition may contain a coloring material. As the coloring material, various pigments and dyes that impart glossy colors such as black, white, magenta, cyan, yellow, green, orange, gold, and silver are used depending on the purpose and required characteristics of the liquid composition. Can be used.
The content of the coloring material is not particularly limited and can be appropriately determined in consideration of a desired color concentration, dispersibility in the composition, etc., but is 0.1 with respect to the total amount of the liquid composition. It is preferably mass% or more and 20 mass% or less.
The liquid composition may be colorless and transparent without containing a coloring material, and in that case, it is suitable as, for example, an overcoat layer for protecting an image.

As the pigment, an inorganic pigment or an organic pigment can be used, and one kind may be used alone or two or more kinds may be used in combination.
As the inorganic pigment, for example, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide can be used.
Examples of the organic pigment include azo pigments such as insoluble azo pigments, condensed azo pigments, azolakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments and isoindolinone pigments. Polycyclic pigments such as quinophthalone pigments, dye chelate (for example, basic dye type chelate, acidic dye type chelate, etc.), dyeing rake (for example, basic dye type rake, acidic dye type rake), nitro pigment, nitroso pigment, Examples include aniline black and daylight fluorescent pigments.

Further, in order to improve the dispersibility of the pigment, a dispersant may be further contained.
The dispersant is not particularly limited, and examples thereof include dispersants commonly used for preparing pigment dispersions such as polymer dispersants.
As the dye, for example, an acid dye, a direct dye, a reactive dye, and a basic dye can be used, and one type may be used alone or two or more types may be used in combination.

<< Organic Solvent >>
The liquid composition may contain an organic solvent, but it is preferable not to contain it if possible.
If the liquid composition does not contain an organic solvent, particularly a volatile organic solvent (VOC (Volatile Organic Compounds) free), the safety of the place where the liquid composition is handled is further enhanced, and it is possible to prevent environmental pollution. Will be. The "organic solvent" means a general non-reactive organic solvent such as ether, ketone, xylene, ethyl acetate, cyclohexanone, and toluene, and should be distinguished from the reactive monomer. be. Further, "not containing" the organic solvent means that it is substantially free of the organic solvent, and it is preferably less than 0.1% by mass.

<< Other ingredients >>
The liquid composition may contain other components, if necessary.
The other components are not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polymerization inhibitor, a leveling agent, an antifoaming agent, a fluorescent whitening agent, a penetration accelerator, a wetting agent ( Moisturizers), fixers, viscosity stabilizers, fungicides, preservatives, antioxidants, UV absorbers, chelating agents, pH regulators, thickeners and the like.

<Preparation of liquid composition>
The liquid composition can be prepared by using the above-mentioned various components, and the preparation means and conditions thereof are not particularly limited. For example, a monomer, a coloring material, a dispersant and the like can be prepared in a ball mill, a kitty mill, a disc mill, a pin mill or the like. , Dynomill, etc., and disperse to prepare a pigment dispersion, which can be further mixed with a monomer, a polymerization initiator, a polymerization inhibitor, a surfactant, and the like. ..

<Viscosity>
The viscosity of the liquid composition is not particularly limited and can be appropriately adjusted according to the application and the application means. For example, when a discharge means for discharging the curable liquid composition from a nozzle is applied. The viscosity at 25 ° C. is preferably 15 mPa · s or more and 40 mPa · s or less, and more preferably 20 mPa · s or more and 40 mPa · s or less. Further, the viscosity in the range of 20 ° C. to 65 ° C. is preferably 5 mPa · s or more and 15 mPa · s or less, and more preferably 6 mPa · s or more and 12 mPa · s or less.
It is particularly preferable that the viscosity range is satisfied without containing the organic solvent.
Here, for the above viscosity, a cone rotor (1 ° 34'× R24) is used with a cone plate type rotational viscometer VISCOMETER TVE-22L manufactured by Toki Sangyo Co., Ltd., the rotation speed is 50 rpm, and the temperature of the constant temperature circulating water is 20. It can be appropriately set and measured in the range of ° C. to 65 ° C. VISCOMATE VM-150III can be used to adjust the temperature of the circulating water.

<Use>
When the ink set is an active energy ray-curable liquid composition, the application is not particularly limited as long as it is in a field where an active energy ray-curable material is generally used, and it can be appropriately selected according to the purpose. Examples thereof include molding resins, paints, adhesives, insulating materials, mold release agents, coating materials, sealing materials, various resists, and various optical materials.
It also includes a cured product obtained by curing an active energy ray-curable liquid composition and a molded product obtained by processing a structure in which the cured product is formed on a substrate. The molded product is, for example, a cured product or structure formed in a sheet shape or a film shape that has been subjected to molding processing such as heat stretching or punching, and is, for example, an automobile, an OA device, or electricity. -Suitably used for applications that require molding after decorating the surface, such as electronic devices, meters for cameras, and panels for operation units.

<Composition container>
The composition containing container means a container in which the liquid composition of the present invention is contained, and is suitable for use in the above-mentioned applications. For example, when the liquid composition is used for ink, the container containing the ink can be used as an ink cartridge or an ink bottle, whereby the ink can be directly applied to the ink in operations such as ink transfer and ink replacement. There is no need to touch it, and you can prevent your fingers and clothes from getting dirty. In addition, it is possible to prevent foreign substances such as dust from being mixed into the ink. Further, the shape, size, material, etc. of the container itself may be suitable for the intended use and usage, and is not particularly limited, but the material is a light-shielding material that does not transmit light, or the container blocks light. It is preferable that it is covered with a sex sheet or the like.

(Manufacturing method of laminated body)
The method for producing a laminate of the present invention includes a first liquid layer forming step and a second droplet layer forming step, preferably including a curing step, and further includes other steps as necessary.
As the method for producing the laminate, the ink set of the present invention described above is used.
The laminate produced by the method for producing a laminate is formed from a first liquid layer (or a cured product thereof) made of a first liquid composition and a second liquid composition on the first layer. It has at least a second droplet layer (or a cured product thereof) to be formed, and further has another layer and other members such as a recording medium, if necessary.

<First liquid layer forming step>
The first liquid layer forming step is a step of forming a first liquid layer composed of the first liquid composition.
As the first liquid composition, the first liquid composition in the ink set of the present invention described above is used.
The first liquid layer forming step is a step of applying the first liquid composition to the recorded medium and forming the first liquid layer composed of the first liquid composition on the recorded medium. May be good.
The method for applying the first liquid composition is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a knife coating method, a nozzle coating method, a die coating method, a lip coating method, a comma coating method, etc. Gravure coat method, rotary screen coat method, reverse roll coat method, roll coat method, spin coat method, kneader coat method, bar coat method, blade coat method, cast method, dip method, curtain coat method, etc. The method etc. can be mentioned. Among these, the inkjet method is preferable.

-Recorded medium-
The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose. For example, natural paper, synthetic paper or other paper, plastic film, non-woven fabric, cloth, wood, metal thin film, leather, glass, etc. Examples thereof include ceramics, building materials, and composite materials thereof. Among these, a durable base material is preferable, and a building material is more preferable.

Examples of the plastic film include a polyester film; a polypropylene film; a polyethylene film; a plastic film such as nylon, vinylon, and acrylic, or a film obtained by laminating the film.
The plastic film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably uniaxially or biaxially stretched from the viewpoint of strength.

The non-woven fabric is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include those obtained by spraying polyethylene fibers in a sheet shape and thermocompression bonding to form a sheet shape.

Examples of the building material include thermosetting resins used in flooring materials, wallpaper, interior materials, wallboard materials, lumbers, ceiling materials, pillars, etc., fiber slabs, particle boards, or the surface of the above materials. Examples thereof include those provided with a decorative board such as a thermosetting resin, olefin, polyester, and PVC.

<Second droplet layer forming step>
In the second droplet layer forming step, the droplets made of the second liquid composition are landed on the first liquid layer, and the second droplet layer made of the second liquid composition is attached to the first liquid layer. This is a step of forming on one liquid layer.
As the second liquid composition, the second liquid composition in the ink set of the present invention described above is used.
The method for landing the droplets composed of the second liquid composition on the first liquid layer is not particularly limited and may be appropriately selected depending on the intended purpose, but may be landed with non-contact or fine droplets. The inkjet method is preferable because it can be laminated without disturbing the liquid layer even if the second liquid composition is landed on the first liquid layer without curing the first liquid layer.

<Curing process>
The curing step is a step of curing the first liquid layer and the second droplet layer.
Examples of the curing means include heat curing and curing with active energy rays, and among these, curing with active energy rays is preferable.
The active energy rays may be any energy rays that can impart energy necessary for advancing the polymerization reaction of polymerizable components such as electron beams, α rays, β rays, γ rays, and X-rays in addition to ultraviolet rays. Not limited. In particular, when a high-energy light source is used, the polymerization reaction can proceed without using a polymerization initiator. Further, in the case of ultraviolet irradiation, mercury-free is strongly desired from the viewpoint of environmental protection, and replacement with a GaN-based semiconductor ultraviolet light emitting device is very useful industrially and environmentally. Further, the ultraviolet light emitting diode (UV-LED) and the ultraviolet laser diode (UV-LD) are compact, have a long life, have high efficiency, and are low in cost, and are preferable as an ultraviolet light source.

<Other processes>
The other steps are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a control step.

(Laminate manufacturing equipment)
The apparatus for producing a laminated body of the present invention comprises a first discharging means for discharging a first curing liquid composition to form a first liquid layer.
It has a second ejection means for ejecting the second curable liquid composition to form a second droplet layer.
It is preferable to have a curing means for curing the first liquid layer and the second droplet layer, and further have other means as needed.
The stack manufacturing apparatus is equipped with the ink set of the present invention described above.

<Image formation method, forming device>
As a method for forming an image, active energy rays may be used, or heating or the like may be mentioned.
In order to cure the cured liquid composition with active energy rays, an irradiation step of irradiating the active energy rays is provided, and the image forming apparatus includes an irradiation means for irradiating the active energy rays and a cured liquid. A storage unit for accommodating the composition may be provided, and the container may be stored in the storage unit. Further, it may have a discharge process and a discharge means for discharging the cured liquid composition. The method of discharging is not particularly limited, and examples thereof include a continuous injection type and an on-demand type. Examples of the on-demand type include a piezo method, a thermal method, and an electrostatic method.

Here, FIG. 1 is a schematic view showing an example of a laminated body manufacturing apparatus according to the present invention, and the laminated body manufacturing apparatus includes an inkjet ejection means. Each liquid composition is ejected to the recording medium 22 supplied from the supply roll 21 by the printing units 23a and 23b including the ink cartridge containing the first liquid composition and the second liquid composition and the ejection head. Will be done. Then, the liquid composition is cured by irradiating it with active energy rays from the light source 24 for curing to form a laminated body. After that, the recording medium 22 is conveyed to the processing unit 25 and the printed matter take-up roll 26. Each of the printing units 23a and 23b may be provided with a heating mechanism so that the recorded medium is liquefied at the recording medium ejection portion. Further, if necessary, a mechanism for cooling the base material to about room temperature by contact or non-contact may be provided. Further, as the inkjet printing method, a serial method in which the head is moved to eject the liquid composition onto the recorded medium with respect to the recorded medium that moves intermittently according to the width of the ejection head, or a serial method in which the liquid composition is continuously ejected is recorded. Any of the line methods in which the medium is moved and the liquid composition is discharged onto the substrate from the head held at a fixed position can be applied.

Examples of the recorded medium 22 include the above-mentioned recorded medium, which is not particularly limited and may be appropriately selected depending on the intended purpose. For example, paper, film, ceramics, glass, metal, or a composite material thereof. Etc., and may be in the form of a sheet. Further, the configuration may be such that only single-sided printing is possible or double-sided printing is possible. It should be noted that the material is not limited to that used as a general base material, and cardboard, building materials such as wallpaper and floor materials, cloth for clothing such as concrete and T-shirts, textiles, leather and the like can be appropriately used.
The laminate manufactured by the ink set of the present invention includes not only those printed on a smooth surface such as ordinary paper or resin film, but also those printed on a surface to be printed having irregularities, metals, ceramics, and the like. Including those printed on the printed surface made of various materials of. Further, by stacking two-dimensional images, it is possible to form a partially three-dimensional image (an image composed of two-dimensional and three-dimensional) or a three-dimensional object.

FIG. 2 is a schematic view showing a state of formation of a laminated body using an example of a laminated body manufacturing apparatus according to the present invention. As the apparatus for manufacturing the laminate, an inkjet ejection device in which a plurality of inkjet heads and a UV light source are mounted on a series of carriages was used. From the left, the first liquid composition 32 discharged from the discharge means 35 equipped with the first liquid composition lands on the recording medium 31, and the first liquid layer 38 made of the first liquid composition 32. The first liquid layer 38 in which the second liquid composition 33 discharged from the discharge means 36 equipped with the second liquid composition and the first liquid layer forming step of forming the first liquid composition is composed of the first liquid composition. A second droplet layer forming a second droplet layer 39 composed of the second liquid composition 33 on the first liquid layer 38 by landing on the surface of the first liquid layer 38 and spreading on the surface of the first liquid layer 38. The forming step and the curing step of curing by the active energy ray 34 irradiated from the active energy ray irradiating means 37 are shown respectively.
The inkjet printing apparatus includes a first ejection means 35 for ejecting the first liquid composition 32, a second ejection means 36 for ejecting the second liquid composition 33, and an active energy ray 34. It is preferable to have an active energy ray irradiating means 37 for irradiating and curing the active energy beam in this order.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

(Example 1)
-Preparation of active energy ray-curable liquid composition-
First, 18 parts by mass of acryloylmorpholine (ACMO), 40 parts by mass of phenoxyethyl acrylate (PEA), 30 parts by mass of cyclic trimethylolpropane formal acrylate (CTFA), 2 parts by mass of aliphatic urethane acrylate (CN963), and 2,4. , 6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO) 10 parts by mass was added and stirred to obtain a common composition of the first liquid composition and the second liquid composition.
Next, 12 parts by mass of titanium oxide as a white pigment and 0.1 part by mass of RS-76-NS as a surfactant were added to the first liquid composition as a magenta pigment to the second liquid composition. Add 3 parts by mass of PR122, 0.01 part by mass of Twin4000 as a surfactant, and 0.001 part by mass of Rad2500, and stir them to make the first liquid composition and the second liquid of Example 1, respectively. An ink set with the composition was obtained.
The "lower layer" in Table 1 indicates the first liquid composition and the first liquid layer composed of the first liquid composition, and the "upper layer" refers to the second liquid composition and the second liquid composition. The second droplet layer composed of the liquid composition is shown.

(Example 2 and Comparative Examples 1 to 3)
-Preparation of active energy ray-curable liquid composition-
In Example 1, the first liquid composition and the second liquid composition of Example 2 and Comparative Examples 1 to 3 are the same as in Example 1 except that the composition and content are changed to those shown in Table 1. An ink set with objects was prepared.

Next, the static surface tension and the dynamic surface tension of each of the obtained liquid compositions were measured as follows. The results are shown in Table 1.

<Static surface tension>
It was measured at 25 ° C. using an automatic surface tensiometer (DY-300, manufactured by Kyowa Surface Chemistry Co., Ltd.) and a platinum plate by the plate method.

<Dynamic surface tension>
Using a dynamic surface tension meter (DynoTester, manufactured by SITA), the dynamic surface tension at 15 msec and 1500 msec was measured at 25 ° C.

-Measurement of cross-sectional area of the second droplet layer using an ink set and evaluation of image quality-
Next, using the prepared ink set, a laminated body was prepared by the combination shown in Table 1 below. Although pigments are appropriately added for image quality evaluation and evaluation of the multilayer formation state, the color combination is not always suitable for an actual printed matter.
For an inkjet ejection device in which a plurality of inkjet heads and a UV light source are mounted on a series of carriages as shown in FIG. 2, MH5421 (manufactured by Ricoh Co., Ltd.) is used as an inkjet head, and a UV-LED having a wavelength of 395 nm is used as an active energy ray irradiation device. A light source was mounted, the liquid composition was mounted in the combination shown in Table 1, and printing was performed at a wavelength of 20 kHz and a carriage speed of 847 mm / s. The specifications of the MH5420 are a laminated piezo push mode method, the number of nozzles is 1280 (320 × 4 rows), the nozzle pitch is about 0.1693 mm / row, and the maximum drive frequency is 30 kHz for single drop and 20 kHz for multi drop. A polycarbonate base material (manufactured by Mitsubishi Gas Chemical Company, Inc.) was used as the recording medium.

Using the inkjet ejection device, an ink set consisting of two liquid compositions is ejected on a polycarbonate substrate (manufactured by Mitsubishi Gas Chemical Company, Inc., Iupiron NF-2000, average thickness 0.5 mm) in the same scan of one scan. And UV irradiation was performed. In Table 1, in the case of "0.2s", the time from the passage of the ejection unit to the passage of the UV irradiator is 0.24 seconds, and the gap between the base material and the head is 1 mm. , The droplet was ejected under the condition that the velocity after flying 1 mm was 7 m / s. The ones described as "2s", "10s", and "30s" are 2 seconds, 10 seconds, and 30 after the ink set consisting of the two liquid compositions lands on the recording medium, respectively. UV irradiation was performed after a second.

The first liquid composition (lower layer) was printed in a 2 cm square size, and the second liquid composition (upper layer) was printed in a 1 cm square size in the center of the lower layer printing. The output of the UV-LED light source with a wavelength of 395 nm is 4.5 W / cm ² , the moving speed of the carriage is 840 mm / sec, the distance from the head to the UV irradiator is 20 cm, and the amount of drops per drop is 18 ng. As for the dot density, the first liquid composition was set to 600 dpi × 600 dpi, and the average thickness was set to 10 μm. The second liquid composition was 150 dpi × 150 dpi when measuring the cross-sectional area, and 600 dpi × 600 dpi when evaluating the image area change rate and the surface coverage rate.

<Measurement of the maximum cross section of the second droplet layer and the exposed cross section of the second droplet layer>
A color image and a laser microscope image were obtained using a laser microscope (OLS4100, manufactured by Olympus Corporation). In the color image and the laser image, dot images of different sizes may be obtained for the second droplet layer, and the maximum cross-sectional area _AM (μm ² ) of the second droplet layer was obtained from the dot image in the color image. .. The cross-sectional area (exposed cross-sectional area) _AE (μm ² ) of the second droplet layer exposed on the first liquid layer was measured from the dot image in the laser image. In addition, the ratio ( _AE / _AM ) (%) of the two cross-sectional areas was determined. The ratio ( _AE / _AM ) is preferably 90% or more.

The prepared laminate was evaluated for the image area change rate and surface coverage rate of dot density 600 dpi × 600 dpi as follows. The results are shown in Table 1.
<Image area change rate>
In an image with a dot density of 600 dpi x 600 dpi, the image area (cm ² ) 10 seconds after the landing of the second liquid composition is the image area (cm) 0.2 seconds after the landing, based on the input image size 1 cm square. From ² ), it was calculated how much the size changed.
The image area was defined as the area of the image including not only the dark-colored portion of the upper layer coloring portion (magenta in this embodiment) but also the lightly blurred and spread portion.
The image area change rate (%) is calculated by the following formula: ("Image area 0.2 seconds after landing"-"Image area 0.2 seconds after landing") / "Image 0.2 seconds after landing" Obtained from "area".
When the image area change rate is 35% or less, there is no image defect and it is good.
[Evaluation criteria]
〇: 35% or less △: 36% or more and 50% or less ×: 51% or more and 100% or less

<Surface coverage>
For an image having a dot density of 600 dpi × 600 dpi, which was irradiated with UV 0.2 seconds after the impact of the second liquid composition, 1 cm composed of the second liquid composition (upper layer) on the first liquid layer (lower layer). The area (cm ² ) where the first liquid layer (lower layer) is exposed in the color image obtained by observing the surface of the central part of the corner image is obtained, and the first liquid layer (lower layer) is the second liquid. The ratio (surface coverage) covered with the composition (upper layer) was calculated.
The surface coverage (%) was determined from the following formula (1- "exposed area of the first liquid layer").
When the surface coverage is 91% or more and 100% or less, the coverage of the lower layer immediately after discharge is excellent and good.
〇: 91% or more and 100% or less Δ: 70% or more and 90% or less ×: 0% or more and 69% or less

From the results in Table 1, Examples 1 and 2 have " _AE / _AM ≥ 0.9" and "-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2". By satisfying the condition, the second droplet landed on the first liquid layer floats and spreads on the surface of the first liquid layer, and the time from the landing of the droplet to the irradiation is 30 seconds. The size change of is less than 20%. Therefore, it can be seen that the ink sets of Examples 1 and 2 can form layers without causing image defects in the state where the lower layer surface is covered. Further, in Examples 1 and 2, "0 ≤ γ _1S -γ _2S ≤ 3" is satisfied, and the static surface tension difference between the upper and lower layers does not become negative (the lower limit value is 0), so that the second droplet is formed. It can spread on the first liquid layer. Further, since the upper limit value is 3, the force for spreading the second droplet on the surface of the first liquid layer does not increase, so that the second droplet landing on the first liquid layer irradiates. Dot size expansion can be suppressed in the time required.
Further, even when the formulations of the first liquid composition and the second liquid composition are changed, the first liquid composition and the second liquid composition contain the same combination of monomers, and the monomer. Similar results are obtained if the static and dynamic surface tensions do not fall below the static and dynamic surface tensions of the surfactant.

On the other hand, in Comparative Example 1, since “ _AE / _AM ≧ 0.9” is satisfied, the second droplet can float and spread on the first liquid layer. However, Comparative Example 1 does not satisfy "-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2", and the dot size of the second droplet immediately after landing is adjusted. On the other hand, since it has expanded too much, the image area of the produced laminated body has expanded too much, causing poor image quality. Similarly, in Comparative Example 3, the second droplet floats and spreads on the first liquid layer, but the dynamic surface tension difference (γ _{1D_1500} −γ _{2D_1500} ) with a lifetime of 1500 ms between the upper and lower layers is large. Since it becomes a positive value and the static surface tension difference (γ _1S -γ _2S ) exceeds 3, the second droplet that has landed on the first liquid layer has a strong spreading force and spreads instantly immediately after landing. It keeps spreading without stopping. Therefore, in Comparative Example 3, it can be seen that the image area is greatly expanded, the image cannot be formed, and the image quality is poor.
In Comparative Example 2, “ _AE / _AM ≧ 0.9” is not satisfied, and the maximum cross-sectional area _{AM_0.2} of the second droplet layer immediately after landing is also 3840 μm ² or less, so that the first liquid layer The second droplet has landed on the top so that it does not float and dive into the lower layer. When the droplets land so as to dive, the spread of the dots after landing is unlikely to occur in the first place, so the image area does not change significantly. Also in Comparative Example 3, since the second droplet is submerged in the first liquid layer, the image area does not change significantly. However, in Comparative Examples 2 and 3 in which the surface of the first liquid layer cannot be covered and the layer cannot be formed, the target lower layer has excellent coverage and no image defect. It turns out that you can't get it.

The detailed contents of the materials used in the examples and comparative examples in Table 1 are as follows.

<Monomer>
<< Monofunctional Monomer >>
-ACMO: Acryloyl morpholine, manufactured by KJ Chemicals Co., Ltd., ACMO
-CTFA: Cyclic trimethylolpropane formal acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., Viscoat # 200
-PEA: Phenoxyethyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., Viscoat # 192

<< Polyfunctional Monomer >>
-CN963: Aliphatic urethane acrylate, manufactured by Sartmer, CN963J85

<Surfactant>
<< Polysiloxane-based surfactant >>
-Twin 4000: Organically modified siloxane copolymer, manufactured by Evonik, TEGO Twin 4000
<< Silicone-based surfactant >>
-Rad2500: Completely crosslinkable silicone acrylate, manufactured by Evonik, TEGO Rad 2500
<< Fluorosurfactant >>
F-554: Fluorine-containing group / lipophilic group-containing oligomer, manufactured by DIC Corporation, F-554
-RS-76-NS: Fluorine-containing group, hydrophilic group, lipophilic group, UV-reactive self-containing oligomer (DPGDA), manufactured by DIC Corporation, RS-76-NS

<Polymer initiator>
-TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by iGM, Omnirad TPO H

<Color material>
-TiO ₂ : Titanium oxide (coloring material for white ink)
-Magenta pigment: PR122 (coloring material for magenta ink)

Examples of aspects of the present invention are as follows.
<1> Having a first liquid composition and a second liquid composition,
When a droplet having a diameter of 200 μm or less made of the second liquid composition is landed on the first liquid layer made of the first liquid composition to form a second droplet layer, the following It is an ink set characterized by satisfying the relational expressions a) and b).
a) At any time within 10 seconds from 2 seconds after landing, the maximum cross-sectional area of the second droplet layer on the plane parallel to the first liquid layer is _AM (μm ² ), the first. When the cross-sectional area of the second droplet layer exposed on one liquid layer is _AE (μm ² ),
A _E / _AM ≧ 0.9
b) The maximum cross-sectional area 0.2 seconds after the impact of the second droplet layer on the plane parallel to the first liquid layer is _{AM_0.2} (μm ² ), and the second droplet layer. When the maximum cross-sectional area 30 seconds after landing is _{AM_30} (μm ² ),
-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2
<2> The static surface tension of the first liquid composition is γ _1S (mN / m),
The ink set according to <1>, which satisfies the following formula, when the static surface tension of the second liquid composition is γ _2S (mN / m).
0 ≤ γ _1S -γ _2S ≤ 3
<3> The dynamic surface tension of the first liquid composition having a life time of 15 ms was set to γ _{1D_15} (mN / m).
The ink set according to any one of <1> to <2>, which satisfies the following formula, when the dynamic surface tension of the second liquid composition having a life time of 15 ms is γ _{2D_15} (mN / m). ..
0 <γ _{1D_15} -γ _{2D_15}
<4> The dynamic surface tension of the first liquid composition having a life time of 1500 ms was set to γ _{1D_1500} (mN / m).
The ink set according to any one of <1> to <3>, which satisfies the following formula, when the dynamic surface tension of the second liquid composition having a life time of 1500 ms is γ _{2D_1500} (mN / m). ..
γ _{1D_1500} －γ _{2D_1500} <0
<5> The second liquid composition contains at least one surfactant and contains.
The ink set according to any one of <1> to <4>, wherein the content of at least one of the surfactants is 0.001% by mass or more and 0.01% by mass or less.
<6> When the droplet of the second liquid composition is 18 ng, the maximum cross-sectional area _AM (μm ² ) of the second droplet layer satisfies the following formula from <1> to <5>. The ink set described in any of the above.
3840 ≤ _AM ≤ 15300
<7> The ink set according to any one of <1> to <6>, wherein the average thickness of the first liquid layer is 10 μm or more.
<8> When the average thickness of the first liquid layer is 10 μm or more, the maximum cross-sectional area _{AM_0.2} (μm ² ) 0.2 seconds after the impact of the second droplet layer and the above. The maximum cross-sectional area _{AM_30} (μm ² ) 30 seconds after the impact of the second droplet layer is the ink set according to any one of <1> to <7>, which satisfies the following formula.
-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2
<9> The ink set according to any one of <1> to <8>, wherein the first liquid composition and the second liquid composition are active energy ray-curable liquid compositions.
<10> A method for manufacturing a laminate using the ink set according to any one of <1> to <9>.
The first liquid layer forming step of forming the first liquid layer composed of the first liquid composition, and
A second liquid layer composed of the second liquid composition is landed on the first liquid layer, and a second liquid droplet layer made of the second liquid composition is formed on the first liquid layer. Droplet layer formation process and
It is a method of manufacturing a laminated body characterized by containing.
<11> The method for producing a laminate according to <10>, further comprising a curing step of curing the first liquid layer and the second droplet layer.
<12> A first discharging means for discharging the first liquid composition to form the first liquid layer, and
It has a second ejection means for ejecting the second liquid composition to form a second droplet layer.
It is a laminated body manufacturing apparatus characterized in that the ink set according to any one of <1> to <9> is mounted.

According to the ink set according to any one of <1> to <9>, the conventional problems can be solved and the object of the present invention can be achieved.
According to the method for manufacturing a laminate according to any one of <10> to <11> and the apparatus for producing a laminate according to <12>, the conventional problems are solved and the following objectives are achieved. Is the subject. That is, according to the method for manufacturing the laminated body and the manufacturing apparatus for the laminated body, in printing in which a plurality of liquid compositions are simultaneously ejected, the coating property of the lower layer is excellent, there is no image defect, and it is stable over time immediately after ejection. It is possible to provide a method for manufacturing a laminated body capable of producing an excellent laminated body, and an apparatus for manufacturing the laminated body.

1 First liquid layer 2 Second droplet layer 10 Laminated body 31 Recorded medium 32 First liquid composition 33 Second liquid composition 34 Active energy ray 35 Discharge means equipped with the first liquid composition 36 Discharge means equipped with a second liquid composition 37 Active energy ray irradiation means 38 First liquid layer 39 Second droplet layer

Japanese Unexamined Patent Publication No. 2011-23501

Claims (12)

It has a first liquid composition and a second liquid composition,
When a droplet having a diameter of 200 μm or less made of the second liquid composition is landed on the first liquid layer made of the first liquid composition to form a second droplet layer, the following An ink set comprising satisfying the relational expressions a) and b).
a) At any time within 10 seconds from 2 seconds after landing, the maximum cross-sectional area of the second droplet layer on the plane parallel to the first liquid layer is _AM (μm ² ), the first. When the cross-sectional area of the second droplet layer exposed on one liquid layer is _AE (μm ² ),
A _E / _AM ≧ 0.9
b) The maximum cross-sectional area 0.2 seconds after the impact of the second droplet layer on the plane parallel to the first liquid layer is _{AM_0.2} (μm ² ), and the second droplet layer. When the maximum cross-sectional area 30 seconds after landing is _{AM_30} (μm ² ),
-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2 The static surface tension of the first liquid composition was γ _1S (mN / m),
The ink set according to claim 1, wherein the static surface tension of the second liquid composition is γ _2S (mN / m), and the following formula is satisfied.
0 ≤ γ _1S -γ _2S ≤ 3 The dynamic surface tension of the first liquid composition having a lifetime of 15 ms was set to γ _{1D_15} (mN / m).
The ink set according to any one of claims 1 to 2, wherein the dynamic surface tension of the second liquid composition having a life time of 15 ms is γ _{2D_15} (mN / m), and the following formula is satisfied.
0 <γ _{1D_15} -γ _{2D_15} The dynamic surface tension of the first liquid composition having a lifetime of 1500 ms was set to γ _{1D_1500} (mN / m).
The ink set according to any one of claims 1 to 3, wherein the dynamic surface tension of the second liquid composition having a life time of 1500 ms is γ _{2D_1500} (mN / m), and the following formula is satisfied.
γ _{1D_1500} －γ _{2D_1500} <0 The second liquid composition comprises at least one surfactant and comprises
The ink set according to any one of claims 1 to 4, wherein the content of at least one of the surfactants is 0.001% by mass or more and 0.01% by mass or less. The invention according to any one of claims 1 to 5, wherein when the droplet of the second liquid composition is 18 ng, the maximum cross-sectional area _AM (μm ² ) of the second droplet layer satisfies the following formula. Ink set.
3840 ≤ _AM ≤ 15300 The ink set according to any one of claims 1 to 6, wherein the average thickness of the first liquid layer is 10 μm or more. When the average thickness of the first liquid layer is 10 μm or more, the maximum cross-sectional area _{AM_0.2} (μm ² ) 0.2 seconds after the impact of the second droplet layer and the second The ink set according to any one of claims 1 to 7, wherein the maximum cross-sectional area _{AM_30} (μm ² ) 30 seconds after the impact of the droplet layer satisfies the following formula.
-0.2 ≤ ( _{AM_0.2} - _{AM_30} ) / _{AM_0.2} ≤ 0.2 The ink set according to any one of claims 1 to 8, wherein the first liquid composition and the second liquid composition are active energy ray-curable liquid compositions. A method for manufacturing a laminate using the ink set according to any one of claims 1 to 9.
The first liquid layer forming step of forming the first liquid layer composed of the first liquid composition, and
A second liquid layer composed of the second liquid composition is landed on the first liquid layer, and a second liquid droplet layer made of the second liquid composition is formed on the first liquid layer. Droplet layer formation process and
A method for producing a laminate, which comprises. The method for producing a laminate according to claim 10, further comprising a curing step of curing the first liquid layer and the second droplet layer. A first discharging means for discharging the first liquid composition to form a first liquid layer,
It has a second ejection means for ejecting the second liquid composition to form a second droplet layer.
An apparatus for manufacturing a laminate, characterized in that the ink set according to any one of claims 1 to 9 is mounted.

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