JP2018203794A - Aqueous inkjet ink set for substrate for modifying humidity, and manufacturing method of substrate for modifying humidity - Google Patents

Abstract

A high-quality, highly colored decorative image can be formed on a humidity-conditioning substrate using an aqueous inkjet ink. A water-based inkjet ink set for humidity-conditioning substrates comprising a black water-based ink and a non-black water-based ink, wherein the charge density of the black water-based ink is higher than the charge density of the non-black water-based ink by 80 μeq/g or more. be. This ink set may further include a surface treatment liquid, and the absolute value of the difference between the charge density of the black water-based ink and the charge density of the surface treatment liquid is preferably 200 μeq/g or less. [Selection figure] None

Description

  One embodiment of the present invention relates to a water-based inkjet ink set for a humidity control substrate, a method for producing a decorated humidity control substrate, and a decorated humidity control substrate.

  The humidity control building material is a building material for interiors having a function of adjusting humidity in a target space such as a room. A humidity control building material is generally made of a porous material, and has a large number of pores on the surface. The pores absorb and release moisture in the target space to exert a humidity control function.

  Under the humidity control building material labeling system, humidity control building materials that meet the specified humidity control and other requirements stipulated in the humidity control building material criteria can be registered with the Japan Building Materials and Housing Equipment Industries Association. A predetermined humidity-controlled building material mark can be displayed on the wet building material as a quality guarantee. In the moisture conditioning building material judgment criteria, the moisture absorption and desorption amount (JIS A 1470-1: 2014, moisture absorption / desorption test method for moisture conditioning building materials-Part 1: Humidity response method-Absorption / release by humidity fluctuation) Wet test method) and equilibrium water content (ie, water content gradient and average equilibrium water content) (JIS A 1475: 2004, method for measuring the equilibrium water content of building materials) are specified to satisfy predetermined levels. .

  In addition, according to the humidity control performance evaluation criteria of the humidity control building materials compiled by the humidity control building materials performance evaluation committee in March 2006, the humidity control materials according to the above moisture absorption / release amount and the equilibrium moisture content are shown in Table 1 below. There are three classes. Here, the first grade satisfies the performance that should be possessed at the minimum as a humidity control building material, the third grade has an excellent performance as a humidity control construction material, the second grade has an intermediate performance between the first grade and the third grade. ing. The humidity control performance evaluation standards for humidity control building materials are posted on the homepage of the Building Materials Testing Center (http://www.jtccm.or.jp/main_services/seino/seino_jigyou_cyositu.html). As for the wettability, the moisture absorption amount at a relative humidity of 50 to 75% exceeds the numerical value shown in Table 1 below, and the moisture release amount is specified to be approximately 70% or more of the moisture absorption amount for 12 hours after 12 hours. The equilibrium moisture content is defined such that the value of the equilibrium moisture content (volume-based mass moisture content) in the moisture absorption process is greater than the values in Table 1 below.

When using a humidity control building material as an interior material, it is desired to enhance the design by decorating the surface of the humidity control building material, and a method of decorating the humidity control building material has been proposed.
Japanese Patent Application Laid-Open No. 2003-146775 (Patent Document 1) discloses a technique for obtaining a building material having excellent design properties by baking the surface of a humidity-controlled building material obtained by blending unexpanded vermiculite with calcium silicate. Proposed.
Japanese Patent Application Laid-Open No. 2011-26871 (Patent Document 2) proposes a technique for decorating a surface of a humidity control building material by forming an image with an ink jet recording means using an ultraviolet curable ink.

The humidity control building material exhibits its humidity control function more when fine holes with a size of about 1 to 50 nm called mesopores absorb and release moisture. When decorating humidity control building materials with ink, it is important to devise so as not to block the holes. Moreover, since the humidity control building material is generally used in an indoor space, it is desired to be decorated with water-based ink that can reduce the amount of organic solvent.
In JP-A-2015-127499 (Patent Document 3), the surface of a porous substrate is finely decorated by decorating a humidity-conditioning building material using an aqueous inkjet ink containing a color material having a small particle diameter and a water-dispersible resin. It has been proposed to obtain vivid color with a small amount of coloring material without damaging the holes and without impairing the humidity control performance. In Patent Document 3, it is proposed to further improve glossiness and humidity control performance by combining pretreatment liquids.
In Japanese Patent Laid-Open No. 2016-210838 (Patent Document 4), a humidity control building material is decorated with an aqueous inkjet ink containing at least one surfactant selected from acetylene glycol surfactants and silicone surfactants. By doing so, while the water in the ink permeates the inside of the base material, the coloring material and the water-dispersible resin in the ink are well fixed on the surface of the base material, thereby improving the water resistance of the decorative image. Proposed. In Patent Document 4, it is proposed to further improve color developability and glossiness by combining surface treatment liquids.

In addition, when decorating a humidity control building material with water-based ink, the surface is porous unlike a general paper medium, so that bleeding of the decorated image is a particular problem. Moreover, when decorating using multicolor ink, there exists a problem that a color mixes on the humidity-control building material surface, and an image quality falls.
Patent Documents 5 to 8 propose methods for preventing image bleeding and color mixing with respect to various substrates that are not porous.

  In WO2012 / 132403 (Patent Document 5), a receiving solution containing a specific metal salt having a valence of 2 or more and a specific resin and / or resin emulsion is attached to a recording medium, and a pigment is formed on the receiving solution attaching portion. By using a water-based ink in which a phosphorus-containing group having at least one P—O or P═O bond is bonded to the surface and / or the surface of the anionic resin emulsion, the fixability is improved, and feathering is performed. It has been proposed to suppress color bleed.

  In JP2013-010823A (Patent Document 6), printing is performed on paper using an ink set in which black ink and ink of a color other than black are made to have different ink viscosities together with the constitution of a water-soluble organic solvent. Therefore, it has been proposed to suppress the occurrence of color bleeding between black and a color other than black.

  In JP 2011-006672 A (Patent Document 7), a black pigment ink containing an anionic self-emulsifying ether polyurethane resin having an acid value of 65 to 85, and an acid value of 10 to 10 than the resin of the black pigment ink. It has been proposed to prevent color bleeding by printing on paper using a color pigment ink containing 40 low anionic self-emulsifying ether polyurethane resin.

  JP 2011-508797 A (Patent Document 8) includes a carbon black pigment and an amphoteric polymer dispersant that is a block copolymer, and destabilizes the black ink having a pH higher than 7 and the carbon black pigment of the black ink. It has been proposed to use a second ink containing reactive species to prevent bleeding of the black ink to other colors when printing the black ink in the proximity of the second ink.

JP 2003-146775 A JP 2011-26871 A JP, 2015-127499, A JP 2016-210838 A WO2012 / 132403 JP 2013-010823 A JP 2011-006672 A Special table 2011-508797 gazette

The technique of Patent Document 3 requires that the surface of the humidity-controlled building material be heated at a high temperature for the baking process, and as a result, the components internally added to the building material may be carbonized and become black. It is difficult to express a full color image.
In the technique of Patent Document 4, since the humidity control performance is lowered at the portion where the ultraviolet curable ink is attached, the image area must be reduced to 1/3 or less of the surface area of the porous substrate. In addition, there is a high possibility that uncured ultraviolet curable ink will remain inside the humidity control building material, which causes a problem in safety as an interior material, and there is a concern about an adverse effect on the human body.

In the method of Patent Document 5, color bleed of a plurality of color inks is suppressed by treating the recording medium with a specific receiving solution. However, in the plurality of color inks, the same components other than the pigment are used. Yes. Therefore, when a plurality of color inks are overlapped and printed, color mixing cannot be sufficiently prevented among the plurality of color inks.
In the method of Patent Document 6, when the black ink and the color ink having similar components other than the colorant are printed while overlapping with each other, although the ink viscosity is different, it becomes easy to become familiar with both inks in contact with each other on paper. Color bleeding cannot be prevented sufficiently. Also, when the solvent composition and ink viscosity vary greatly depending on the ink, it may be necessary to change the print head depending on the color.

In the methods of Patent Documents 7 and 8, a component that agglomerates the pigment of the black ink is blended in the color ink, and the black ink and the color ink come into contact with each other on the paper surface, so that the pigment of the black ink aggregates, Bleeding and color mixing are prevented. In this method, when black ink and color ink are mixed in the vicinity of the ink discharge portion of the ink jet nozzle, there is a problem that the ink aggregates on the surface of the ink jet nozzle and causes discharge failure. For example, ink may be mixed in the operation of cleaning the inkjet head or wiping the nozzle surface.
In addition, by varying the acid value of the resin between inks as in Patent Document 7 or adjusting the pH of the ink as in Patent Document 8, color bleeding cannot be sufficiently prevented, and in particular, a humidity control building material Then, color blur becomes a problem.

In Patent Documents 5 to 8, color bleeding on a paper medium is mainly examined.
In the case where a decorative image is formed using a water-based ink on a humidity control building material, since there are many large holes exceeding 50 nm, which are referred to as macro holes, in the humidity control building material, the dot shape of the ink follows the macro holes. May be deformed or the ink may penetrate into the macropores, resulting in bleeding or a decrease in color developability. Furthermore, in color printing, color mixing may occur in a portion where a plurality of colors overlap, and the quality of the decorated image may be reduced.
In addition, it is desired that the humidity control building material has sufficient color developability with a small amount of coloring material and resin component so as not to block the above-described mesopores.
Therefore, in printing on humidity-controlled building materials, measures different from printing on paper media are more important in terms of bleeding, color developability, and color mixing.

  Accordingly, an object of the present invention is to form a high-quality and highly colored decorative image on a humidity control substrate using an aqueous inkjet ink. Another object of the present invention is to form a decorative image having excellent scratch resistance and glossiness on a humidity control substrate by combining this ink set and a surface treatment liquid.

  One embodiment of the present invention comprises a black aqueous ink and a non-black aqueous ink, wherein the black aqueous ink has a charge density of 80 μeq / g or more higher than the charge density of the non-black aqueous ink. A water-based inkjet ink set for use.

Another embodiment of the present invention is a method for producing a decorated humidity control substrate, including a step of performing inkjet printing on the humidity control substrate using the above-described aqueous inkjet ink set for a humidity control substrate.
Still another embodiment of the present invention includes a decorative image formed using the above-described water-based inkjet ink set for a humidity control substrate, and the moisture absorption after 3 hours measured according to JIS A 1470-1 (2014). Is a decorated humidity conditioning substrate with more than 15 g / m ² .

  According to one embodiment, a decorative image with high image quality and high color can be formed on a humidity control substrate using an aqueous inkjet ink. Further, by combining this ink set and the surface treatment liquid, it is possible to form a decorative image having excellent scratch resistance and glossiness on the humidity control substrate.

Hereinafter, although one Embodiment of this invention is described in detail, it cannot be overemphasized that this invention is not limited to these Embodiment, and various corrections and changes may be added.
The water-based inkjet ink set for a humidity control substrate according to one embodiment includes a black aqueous ink and a non-black aqueous ink, and the charge density of the black aqueous ink is 80 μeq / g or more than the charge density of the non-black aqueous ink. It is characterized by being expensive.
Hereinafter, the water-based inkjet ink set for the humidity control substrate is also simply referred to as “ink set”, and the black aqueous ink is also simply referred to as “black ink”. As the water-based ink other than black, inks of respective colors such as white, light cyan, and light magenta can be used in addition to the three colors of cyan, magenta, and yellow used in general color inks. These water-based inks other than black are hereinafter also simply referred to as “color inks”. The charge density is also referred to as “Cd value”.

  According to one embodiment, it is possible to provide an ink-jet ink set that forms a high-quality and highly colored decorative image on a humidity control substrate. According to this ink set, it is possible to prevent a decrease in the humidity control performance of the humidity control substrate. Further, by combining this ink set and the surface treatment liquid, it is possible to form a decorative image having excellent scratch resistance and glossiness on the humidity control substrate.

<Humidity control substrate>
The humidity control substrate is not particularly limited as long as it is a porous substrate having a humidity control function. Preferably, the humidity control substrate has a large number of pores on the surface and inside, and these pores exhibit moisture absorption / release properties.
Hereinafter, the “porous substrate” that is preferably used as the humidity control substrate will be described.
The shape of the porous substrate is usually a board shape, that is, a plate shape, but is not limited thereto.
The diameter of the pores of the porous substrate is, for example, about 1 to 200 nm or 1 to 100 nm, and more specifically, mesopores having a diameter of 1 to 50 nm and a diameter of more than 50 nm (for example, more than 50 nm or less than 200 nm or Some have macropores of more than 50 nm and about 100 nm or less. The diameter of the mesopores can be measured, for example, by a mercury intrusion method using a mercury porosimeter.

As a typical porous substrate, a hardened body of an inorganic material such as calcium silicate, and an inorganic powder having a moisture absorption / release function, for example, siliceous powder, silica gel, diatomaceous earth, activated clay, zeolite , Bentonite, montmorillonite, sepiolite, and the like, and those obtained by further firing the cured product are also included. Specific examples of the porous substrate include those used as materials for humidity control building materials, and preferably, the humidity control building materials registered with the Japan Building Materials and Housing Equipment Industries Association. That is, first-class or higher-grade humidity-control building materials having performance that matches the humidity-control performance evaluation criteria shown in Table 1 above can be preferably used. For example, as described above, it is a porous substrate having a moisture absorption amount after 3 hours as defined in JIS A 1470-1 (2014) of more than 15 g / m ² .

  More specifically, for example, a hydrophilic material selected from at least one of gypsum, calcium silicate, cement, slag gypsum, or basic magnesium carbonate as described in JP-A-2003-146775 (Patent Document 1). A humidity control building material obtained by molding a material, and a moisture control building material obtained by molding a material in which an expandable / peelable mineral is blended with the hydrophilic material, as described in JP 2002-4447 A (none) Examples include a humidity control building material produced by a carbonic acid curing reaction of a molded body whose main components are calcium carbonate and amorphous silica. In particular, a humidity-conditioning building material obtained by molding a material obtained by blending calcium silicate with unexpanded vermiculite as described in JP-A-2003-146775 (Patent Document 1) can be preferably used.

The humidity control substrate can be preferably used as a humidity control building material having a function of mainly absorbing and releasing moisture such as indoor space.
As humidity control building materials, those made from various porous materials are known. For example, as a humidity control building material composed of calcium silicate and unexpanded vermiculite, Mois (trade name) of Aika Industry Co., Ltd. ), Daiken Industry Co., Ltd.'s Sarai Art (trade name), LIXIL (INAX) Eco Carat (trade name), Nagoya Mosaic Co., Ltd. Age Plus (trade name), Sekisui Board Co., Ltd. There are Gaudia (trade name) and Nikko Co., Ltd. monche (trade name).

<Ink set>
The ink set according to an embodiment can be preferably used for decorating the surface of the porous substrate. For example, it can be particularly preferably applied to a humidity control substrate used for a humidity control building material or the like.
In this specification, “decoration” is synonymous with decoration, meaning that a print image is formed on an object, and “decorated” means having a print image. This decorative portion may be the entire surface of the object, that is, the humidity control substrate, or a part thereof.

  With the ink set according to one embodiment, on the surface of the humidity control substrate, without sacrificing the humidity control performance, for example, if it is a humidity control building material, the same grade as before decoration is maintained, and a vivid image with a small amount of color material Can be formed. Even when the printing area of the image extends over the entire surface of the humidity control substrate, the grade of the humidity control building material before decoration can be maintained. In addition, since there is no restriction on the area of the print region, various patterns, characters, and the like can be freely expressed.

The ink set includes black aqueous ink (black ink) and non-black aqueous ink (color ink). Each of the black ink and the color ink may be one type or two or more types.
Preferably, the ink set can include black ink and at least one selected from the group consisting of cyan (C) ink, magenta (M) ink, and yellow (Y) ink.
For example, as a general ink jet ink set for color printing, an ink set including four colors of ink of cyan (C), magenta (M), yellow (Y), and black (K) can be provided. Further, the ink set may include two or more water-based inks having the same color and different hues from the four colors of cyan, magenta, yellow, and black.

In one embodiment, the charge density Cd value of the black ink is preferably 80 μeq / g or more higher than the color ink charge density Cd value, more preferably 100 μeq / g or more, and more preferably 150 μeq / g or more. Even more preferred.
As a result, color mixing and blurring of the black ink and the color ink can be prevented, and the color development of the decorative image can be improved. In such an ink set, since the difference in charge density between the black ink and the color ink is large and the mixing speed is slow, it is considered that the ink is dried before the inks are mixed and the color mixing can be suppressed. .

In the case of providing a plurality of types of color inks, the Cd value of the black ink only needs to be 80 μeq / g or more higher than the Cd value of each color ink.
In the case where a plurality of types of black ink are provided, it is sufficient that the Cd value of any one of the plurality of black inks is 80 μeq / g or more higher than the Cd value of the color ink. Is preferably 80 μeq / g or more higher than the Cd value of the color ink.
For example, in the case of an ink set including four colors of ink of cyan (C), magenta (M), yellow (Y), and black (K), the Cd value of black ink (hereinafter also referred to as Cdk) in the ink set. It is preferable that the Cd value (hereinafter also referred to as Cd2) of the water-based ink having the highest Cd value and the second highest Cd value satisfy the relationship Cdk−Cd2 ≧ 80 μeq / g.

Here, the charge density Cd value is a charge density measured according to the streaming potential method. Further, the charge density Cd value of the ink is a charge amount per effective component in the ink (unit: μeq / g). The amount of active ingredient is the total amount of non-volatile content or solid content contained in the ink, and is mainly the amount obtained by removing the solvent from the ink. When a solvent is contained in the pigment dispersion, dispersant, and water-dispersible resin, the amount of these solvents is also removed to determine the amount of active ingredients.
Specifically, the reaction end point at which the flow potential of the ink becomes 0 V is measured while titrating a 0.0025N polydiallyldimethyl-ammonium chloride (polyDADMAC) solution to the diluted ink 100 times with water. The total charge amount of the diluted ink can be determined from the amount of the polyDADMAC solution used up to this reaction end point. A value obtained by dividing the total charge amount of the diluted ink by the effective component amount contained in the diluted ink is the charge density (μeq / g) of the ink.
For example, a colloid particle charge meter (“Model CAS” manufactured by AFG ANALYTIC GmbH) or the like can be used as the charge density measuring device.

The black ink and color ink charge density can be adjusted by appropriately selecting the components contained in each ink. For example, the charge density of the ink can be adjusted by the counter ion amount of the ionic group of the material constituting the ink. The counter ion amount indicates the ion amount per particle mass. Generally, as the amount of counter ions per particle mass increases, the charge density tends to increase. It is preferable to adjust the charge density by the amount of counter ions of the pigment or water-dispersible resin in the ink. The charge density of the ink can also be adjusted, for example, by adding an ionic component such as a dispersion aid to the ink. Further, the charge density of the ink may be adjusted by combining several methods.
The adjustment of the charge density of the surface treatment liquid described later can be performed in the same manner.

  The charge density of the ink is not a physical property that depends only on the acid value of the resin to be added or the pH of the whole ink. There is no significant difference in density.

In one embodiment, the printing order of the black ink and the color ink is not particularly limited, but it is preferable to apply the black ink after applying the color ink to the porous substrate.
In the case where the black ink is applied over the region where the color ink is applied to the porous substrate, it is possible to prevent color mixing and blurring of the black ink in a portion overlapping with the color ink due to a difference in charge density.
Note that the printing order may be reversed. Even when the color ink is applied in an overlapping manner on the area where the black ink is applied to the porous substrate, color mixing and bleeding of the color ink can be prevented at the portion overlapping the black ink.

  As the black aqueous ink, an ink exhibiting black color, and an ink mainly containing a black pigment and / or a black dye can be preferably used.

The ink set according to an embodiment may further include a surface treatment liquid.
In one embodiment, the absolute value of the difference between the charge density Cd value of the black aqueous ink (black ink) and the charge density Cd value of the surface treatment liquid is preferably 200 μeq / g or less, and is 130 μeq / g or less. It is more preferable.
Thus, the difference “| Cdk−Cdp |” between the charge density Cd value of black ink (hereinafter also referred to as Cdk) and the charge density Cd value of the surface treatment liquid (hereinafter also referred to as Cdp) is small. A decorative image that is more excellent in glossiness and scratch resistance can be formed on the porous substrate.
When | Cdk−Cdp | is small, when the black ink is landed on the surface-treated portion on which the surface treatment liquid has been treated on the porous substrate, the ink easily becomes familiar with the surface-treated portion. After the ink penetrates to the depth, it dries and fixes. Therefore, it is considered that the scratch resistance and glossiness are improved.
On the other hand, when | Cdk−Cdp | is increased, the black ink is less likely to be applied to the surface-treated portion where the surface treatment liquid is treated on the porous substrate, and the ink droplets are relatively large on the porous substrate. It becomes and stays. In such a state, the black ink is not sufficiently fixed to the porous substrate and the scratch resistance is lowered, and the surface of the decorative image by the black ink becomes rough and the glossiness is lowered. become.
Since the black ink is more noticeable when the decorative image is rubbed than the color ink, it is preferable to make the charge density of the surface treatment liquid close to the charge density of the black ink. Further, it is felt that the glossiness of the entire color image is further increased by increasing the glossiness of the black ink.

  In the case where a plurality of types of black ink are provided, the absolute value of the difference between the Cd value of any one of the plurality of black inks and the Cd value of the surface treatment liquid may be 200 μeq / g or less. The absolute value of the difference between all the Cd values of the black ink and the Cd value of the surface treatment liquid is preferably 200 μeq / g or less.

Here, the charge density Cd value is a charge density measured according to the streaming potential method. The charge density Cd value of the surface treatment liquid is the amount of charge per active ingredient amount in the surface treatment liquid (unit: μeq / g). The active ingredient amount is the total amount of non-volatile content or solid content contained in the surface treatment liquid, and is mainly the amount obtained by removing the solvent from the surface treatment liquid. When a solvent is contained in the dispersant and the water-dispersible resin, the amount of these solvents is also removed to determine the amount of active ingredients.
Specifically, as a method for measuring the charge density of the surface treatment solution, the surface treatment solution is diluted 100 times with water, and a 0.0025N polydiallyldimethyl-ammonium chloride (polyDADMAC) solution is titrated in this diluted solution. Can be measured. Details are as described in the above ink.

<Water-based ink>
Hereinafter, the water-based ink constituting the ink set will be described.
The water-based ink according to an embodiment includes at least a coloring material and water, and preferably further includes a surfactant and / or a water-dispersible resin. Components other than the color material can be used in common for the black ink and the color ink.

Water is not particularly limited as long as it functions as an ink solvent, that is, a vehicle, and tap water, ion exchange water, deionized water, and the like can be used. Water is a highly volatile solvent, and since it evaporates easily after being discharged onto the porous substrate, it prevents the pores of the porous substrate after decoration from being blocked and decorated. There exists an effect | action which prevents the fall of the humidity control performance of a porous base material. Moreover, since water is harmless and highly safe and has no problems like VOC, the decorated porous substrate (decorated article) can be made environmentally friendly.
The greater the water content in the ink, the greater the effect of preventing the decrease in humidity control performance of the porous substrate, so water is preferably 60% by mass or more of the total amount of ink, and 65% by mass. More preferably. Moreover, it is preferable that content of water is 95 mass% or less, and it is more preferable that it is 90 mass% or less.

The ink solvent may contain a water-soluble organic solvent in addition to water, if necessary. As the water-soluble organic solvent, an organic compound that is liquid at room temperature and is soluble in water can be used, and a water-soluble organic solvent that is uniformly mixed with the same volume of water at 1 atm 20 ° C. is preferably used. .
For example, lower alcohols such as methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, 2-methyl-2-propanol;
Glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol;
Glycerols such as glycerin, diglycerin, triglycerin, polyglycerin;
Acetins such as monoacetin, diacetin, triacetin; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol dimethyl ether , Glycol ethers such as tetraethylene glycol diethyl ether;
Triethanolamine, 1-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, β-thiodiglycol, sulfolane and the like can be used. These may be used alone or in combination of two or more as long as a single phase is formed.
The content of the water-soluble organic solvent is preferably 50% by mass or less based on the total amount of ink from the viewpoints of viscosity adjustment and moisturizing effect. Moreover, it is preferable that it is 60 mass% or less with respect to the solvent whole quantity.

As the color material, both pigments and dyes can be used, and they may be used alone or in combination. From the viewpoint of the weather resistance of the decorative image and the printing density, it is preferable to use a pigment as the coloring material.
The content of the color material is preferably in the range of 0.01 to 20% by mass with respect to the total amount of ink. Furthermore, the content of the coloring material is more preferably 0.1% by mass or more, further preferably 0.5% by mass or more, and further preferably 1% by mass or more. Further, the content of the coloring material is more preferably 15% by mass or less, further preferably 10% by mass or less, and further preferably 8% by mass or less.

As the pigment, a black pigment, a color pigment, or the like can be used.
Specifically, examples of the pigment include organic pigments such as azo, phthalocyanine, dye, condensed polycyclic, dyed lake, nitro, and nitroso (brilliant carmine 6B, lake red C, watching red, Disazo yellow, hansa yellow, phthalocyanine blue, phthalocyanine green, alkali blue, aniline black, etc.);
Metals such as cobalt, iron, chromium, copper, zinc, lead, titanium, vanadium, manganese, nickel, metal oxides and sulfides, and inorganic pigments such as ocher, ultramarine, and bitumen;
Carbon blacks such as furnace carbon black, lamp black, acetylene black, and channel black can be used.
Examples of the azo pigments include soluble azo lake pigments, insoluble azo pigments and condensed azo pigments.
Examples of phthalocyanine pigments include metal phthalocyanine pigments and metal-free phthalocyanine pigments.
Condensed polycyclic pigments include quinacridone pigments, perylene pigments, perinone pigments, isoindoline pigments, isoindolinone pigments, dioxysazine pigments, thioindigo pigments, anthraquinone pigments, quinophthalone pigments, metal complexes Examples thereof include pigments and diketopyrrolopyrrole (DPP).
Moreover, you may use a white pigment as a pigment.
Examples of white pigments include inorganic pigments such as titanium oxide, zinc white, zinc sulfide, antimony oxide, and zirconium oxide.
These can be used alone or in combination of two or more.

  The average particle size of the pigment is preferably 50 to 500 nm, and more preferably 50 to 200 nm. When the average particle diameter of the color pigment is less than 50 nm, the color development may be insufficient, and when it exceeds 500 nm, the ejection stability may be insufficient.

Specific examples of the pigment include Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 94, 95, 109, 110, 117, 120, 125, 128, 137, 138, and 139. 147, 148, 150, 151, 154, 155, 166, 168, 180, 185;
Pigment orange 16, 36, 38, 43, 51, 55, 59, 61, 64, 65, 71;
Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 149, 168, 177, 178, 179, 206, 207, 209, 242, 254, 255;
Pigment violet 19, 23, 29, 30, 37, 40, 50;
Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 30, 64, 80;
Pigment green 7 (chlorinated phthalocyanine green), 36 (brominated phthalocyanine green);
Pigment brown 23, 25, 26;
Pigment black 7 (carbon black), 26, 27, 28, and the like.

Examples of commercially available carbon black include Monarch 1000, ELFTEX 415 (above, carbon black manufactured by Cabot Corporation), # 960, MA8, MA11 (above, carbon black manufactured by Mitsubishi Chemical Corporation), and the like.
Examples of commercially available color pigments include LIONOL BLUE FG-7400G (phthalocyanine pigment manufactured by Toyo Ink Co., Ltd.);
YELLOW PIGMENT E4GN (Nickel complex azo pigment manufactured by Bayer);
Chrophtal Pink PT (BASF quinacridone pigment);
Fastogen Super Magenta RG (a quinacridone pigment manufactured by DIC);
YELLOW PIGMENT E4GN (a nickel complex azo pigment manufactured by LANXESS);
Irgalite Blue 8700 (phthalocyanine pigment manufactured by BASF);
E4GN-GT (a nickel complex azo pigment manufactured by LANXESS);
Fastogen Blue TGR (DIC Corporation Cyan Pigment);
Cinquasia Magenta D4550J (magenta pigment manufactured by BASF);
Inkjet Yellow 4GP (yellow pigment manufactured by Clariant) and the like.

When a pigment is used, a pigment dispersant may be included in the ink for the dispersion stability of the pigment. As the pigment dispersant, a polymer dispersant, a surfactant or the like can be used.
Examples of commercially available polymer dispersants include the TEGO Disperse Series (TEGO Disperse 740W, TEGO Disperse 750W, TEGO Disperse 755W, TEGO Disperse 757W, TEGO Disperse 760, and TEGO Disperse 760W manufactured by EVONIK. );
Solsperse series (Solsperse 20000, 21000, 27000, 41000, 41090, 43000, 44000, 46000) manufactured by Nippon Lubrizol Corporation;
John Crill series manufactured by Johnson Polymer Co., Ltd. (John Crill 57, John Crill 60, John Crill 62, John Crill 63, John Crill 71, John Crill 501);
BYK's DISPERBYK-102, 180, 184, 185, 187, 190, 191, 192, 194N 193, 199;
FUJI SP A-54 made by Fuji Pigment;
Examples include polyvinyl pyrrolidone K-30 and polyvinyl pyrrolidone K-90 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Examples of commercially available surfactants include anionic surfactants such as Kao Corp. Demol series (Demol EP, Demol N, Demol RN, Demol NL, Demol RNL, Demol T-45);
Nonionic surfactants such as Kao's Emulgen series (Emulgen A-60, Emulgen A-90, Emulgen A-500, Emulgen B-40, Emulgen L-40, and Emulgen 420) can be mentioned.
These can be used alone or in combination of two or more.

  Although the blending amount of the pigment dispersant varies depending on the type, it can be blended in an amount of 0.005 to 0.5 with respect to the pigment 1 in terms of the mass ratio of the active ingredient.

  Self-dispersing pigments may be used as the pigment. As the self-dispersing pigment, it is preferable that a hydrophilic functional group having ionicity is introduced, and the pigment particles are stabilized in water by electrostatic repulsion by charging the pigment surface anionic or cationic. Can be dispersed. As the anionic functional group, a sulfonic acid group, a carboxy group, a carbonyl group, a hydroxy group, a phosphonic acid group, a phosphoric acid group and the like are preferable. As the cationic functional group, a quaternary ammonium group, a quaternary phosphonium group and the like are preferable. Among these, an anionic group such as a carboxy group, a hydroxy group, and a phosphate group is preferable.

  These hydrophilic functional groups may be directly bonded to the pigment surface or may be bonded via other atomic groups. Examples of other atomic groups include, but are not limited to, an alkylene group, a phenylene group, and a naphthylene group. Examples of the treatment method for the pigment surface include diazotization treatment, sulfonation treatment, hypochlorous acid treatment, humic acid treatment, and vacuum plasma treatment.

Among the self-dispersing pigments, commercially available pigments include, for example, CAB-O-JET series (CAB-O-JET200, CAB-O-JET300, CAB-O-JET250C, CAB-O-JET260M, CAB- manufactured by Cabot Corporation). O-JET270C, CAB-O-JET 270Y, CAB-O-JET 450C, CAB-O-JET 465M, CAB-O-JET 470Y, etc.);
BONJET BLACK CW-1S, CW-2, CW-3, CW-4, CW-5, CW-6, etc. manufactured by Orient Chemical Co., Ltd .;
Examples include Smart Magenta 3122BA manufactured by SENSIJET.
Moreover, you may use the microencapsulated pigment which coat | covered the pigment with resin.

  As the dye, those generally used in the technical field of printing can be used and are not particularly limited. Specific examples include basic dyes, acid dyes, direct dyes, soluble vat dyes, acid mordant dyes, mordant dyes, reactive dyes, vat dyes, sulfur dyes, etc. Among these, water-soluble dyes, reduction dyes, etc. Those that become water-soluble can be used. More specifically, examples include azo dyes, rhodamine dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, triphenylmethane dyes, diphenylmethane dyes, and methylene blue. These dyes may be used alone or in combination of two or more.

The water-dispersible resin is blended in order to sufficiently fix the color material on the porous substrate, whereby high colorability can be obtained with a small amount of color material.
As the water dispersible resin, it is preferable to use a resin that forms a transparent coating film. Further, it is preferable to use a resin capable of forming particles in an aqueous ink, that is, a resin capable of forming an oil-in-water (O / W) type resin emulsion, and can be blended as a resin emulsion.
Typically, ethylene-vinyl chloride copolymer resin, (meth) acrylic resin, styrene / maleic anhydride copolymer resin, urethane resin, vinyl acetate- (meth) acrylic copolymer resin, vinyl acetate-ethylene copolymer Examples include coalesced resins, styrene / (meth) acrylic copolymer resins, and resin emulsions thereof. Here, “(meth) acrylic resin” refers to both acrylic resin and methacrylic resin.

Of these water-dispersible resins or resin emulsions thereof, diatomaceous earth, vermiculite, kaolinite, gypsum, tiles that are used as raw materials for porous substrates such as humidity control building materials and the viewpoint of stable ejection performance from inkjet heads From the viewpoint of adhesion to inorganic porous materials such as chamotte, slaked lime, and ceramic porous powder, it is preferable to use a urethane resin (emulsion) having a glass transition temperature (Tg) of −35 to 40 ° C.
As a specific example of such water-dispersible resin or its resin emulsion,
Superflex 300, 460, 420, 470, 460S (carbonate urethane resin emulsion), 150HS (ester / ether urethane resin emulsion), 740, 840 (aromatic isocyanate ester urethane resin) from Daiichi Kogyo Seiyaku Co., Ltd. Emulsion);
DSM NeoRez R-9660, R-2170 (aliphatic polyester urethane resin emulsion), NeoRez R-966, R-967, R-650 (aliphatic polyether urethane resin emulsion), R-986, R- 9603 (aliphatic polycarbonate);
ADEKA Corporation Adekabon titer HUX-370, 541, 550, 1032, etc. (all are trade names).

Also, from the viewpoint of high compatibility with each ink material, good stability as an ink, and low cost, and the ink can be designed at low cost, (meth) acrylic resin or styrene / (meth) acrylic resin It is also preferable to use.
Specifically, Nippon Vinyl Synthetic Chemical Industry Co., Ltd. Mobile 966A, 6963, 6960 (acrylic resin emulsion), 6969D, RA-033A4 (styrene / acrylic resin emulsion);
BASF Jonkrill 7100, PDX-7370, PDX-7341 (styrene / acrylic resin emulsion);
DIC Corporation's Boncoat EC-905EF, 5400EF, CG-8400 (acrylic / styrene emulsion);
Examples include NeoCryl BT-62, XK-190, A-1094 (styrene acrylic water-dispersible resin) manufactured by DSM (all are trade names).
The water dispersible resin may be composed of one kind of resin (or emulsion thereof) such as urethane resin, (meth) acrylic resin, styrene / (meth) acrylic resin, or plural kinds of resins (or Those emulsions) may be combined.

The water dispersible resin is particulate in the ink. The water-dispersible resin particles may have a particle size that is suitable for inkjet printing, and is generally preferably 300 nm or less in average particle size. Moreover, if it is this magnitude | size suitable for inkjet printing, since the pores of a porous base material are not block | closed completely and humidity control performance can be maintained, it is preferable. In order to maintain the humidity control performance, a more preferable value of the average particle diameter is 250 nm or less, a more preferable value is 200 nm or less, a more preferable value is 150 nm or less, and a most preferable value is 90 nm or less. Further, when a pigment is used as the color material, from the viewpoint of further improving the binding property between the pigment particles, the particle size of the water-dispersible resin particles is the average particle size of the pigment (generally about 80 to 200 nm). Is preferably smaller.
The lower limit of the average particle diameter of the water-dispersible resin particles is not particularly limited, but is preferably about 5 nm or more, and more preferably 10 nm or more, from the viewpoint of the storage stability of the ink.

  In this specification, unless otherwise specified, the average particle diameter is a volume-based particle diameter value (median diameter) in a particle size distribution measured by a dynamic light scattering method. As the dynamic light scattering particle size distribution measuring device, a nano particle analyzer nano Partica SZ-100 (Horiba, Ltd.) or the like can be used. In the ink or the surface treatment liquid described later, the water-dispersible resin particles and the inorganic particles may be present in the form of independent fine particles or in the state of aggregates where the independent fine particles are aggregated. However, the median diameter measured by the dynamic light scattering method is regarded as the “average particle diameter”.

  The average particle size of the resin particles is preferably measured in the state of the raw material emulsion before preparing the ink because the influence of the coloring material (pigment particles) can be excluded, and the measured value is the average particle size of this embodiment. It can be a diameter.

  The amount of the water-dispersible resin (effective component amount) in the ink is preferably 1: 0.5 to 1: 7 (mass ratio) in terms of the ratio of the colorant to the water-dispersible resin (colorant: water-dispersible resin). 1: 0.75 to 1: 5.0 is more preferable. By setting the content of the water-dispersible resin within this range, it is possible to sufficiently ensure the water scratch resistance and high image quality of an image printed on the surface of the porous substrate. If the ratio of the water-dispersible resin to the color material 1 is less than 0.5, the fixability of the pigment may be deteriorated. If it is greater than 7, the viscosity increases, and ink can be ejected from the head that ejects ink. There is a possibility of disappearing.

  It is preferable to add a surfactant because it is easier to stably eject ink by an ink jet method, and the permeation of the ink can be appropriately controlled. The amount added (as the total amount when a surfactant is used as a pigment dispersant) varies depending on the type of the surfactant, but the surface tension of the ink and the penetration rate into the substrate such as a fabric In view of the above, it is preferably in the range of 0.1 to 10% by mass in the ink.

  Surfactants include acetylene glycol surfactants, silicone surfactants, anionic surfactants (alkyl sulfate esters, polyoxyethylene alkyl ether sulfates, alkylbenzene sulfonates, etc.), nonionic interfaces Examples include activators (polyoxyethylene alkyl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, etc.), fluorine-based surfactants, and the like. These can be used alone or in combination of two or more.

  Of these, acetylene glycol surfactants and silicone surfactants can be preferably used. Since these surfactants give the ink good wettability to the porous substrate, a high-quality image can be formed on the porous substrate. Further, these surfactants can effectively suppress the aggregation of the resin particles even when the water-dispersible resin has a small resin particle diameter.

  The acetylene glycol surfactant is a nonionic surfactant having an acetylene glycol group. Examples of commercially available products include Surfynol 104E and 104H, which are acetylene glycols, Surfynol 420, 440, 465, and 485 having a structure in which ethylene oxide is added to acetylene glycol (Air Products and Chemicals), Olfine E-1004 of acetylene glycol, E-1010, E-1020, PD-002W, PD-004, EXP-4001, EXP-4200, EXP-4123, EXP-4300, etc. (Nissin Chemical Industry Co., Ltd.), acetylene glycol acetylenol E00, E00P, acetylene Examples include acetylenol E40 and E100 having a structure to which ethylene oxide of glycol is added (Kawaken Fine Chemical Co., Ltd.).

  Specific examples of the silicone surfactant include BYK-302, BYK-307, BYK-325, BYK-331, BYK-333, BYK-342, BYK-345 / 346, BYK-347, BYK-348. BYK-349, BYK-378 (all are Big Chemie Japan Co., Ltd.), L-7001, L-7002, L-7604, FZ-2105, 8032 ADDITIVE (all are Toray Dow Corning Co., Ltd.), KF-6011 KF-6011P KF-6013 KF-6004 KF-6043 (all Shin-Etsu Chemical Co., Ltd.), Disparon AQ-7120, Disparon AQ-7130, Disparon AQ-7180 (all Enomoto Kasei Co., Ltd.), Silface SAG503A, Sil Face SAG 01, sill face SAG002, sill face SAG003, sill face SAG005, can be mentioned (both Nissin Chemical Industry Co., Ltd.) sill face SAG008 like.

  The amount of the surfactant in the ink is preferably about 0.1% by mass or more, more preferably 0.3% by mass or more, and further preferably 0.5% by mass or more. The amount of the surfactant is preferably about 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less.

In the ink, in order to further improve the dispersion stability of the pigment and the water-dispersible resin, two or more pigment dispersants may be used in combination, and a dispersion aid may be included together with the pigment dispersant.
In general, each ink constituting the ink set uses a component having a structure and characteristics similar to those of the component excluding the color material, and thus the difference in charge density between the inks is often small. Therefore, the difference in the charge density between the black ink and the color ink is adjusted by changing the additive components such as pigment dispersant and dispersion aid, and changing the amount of addition between the black ink and the color ink. can do.

  Dispersing aids can be used alone or in combination with pigment dispersants, even if the pigment dispersibility is not sufficient, or pigment dispersion in addition to ink using self-dispersing pigments. A component having a function of improving stability can be used.

  In addition to the above components, other components such as a humectant, an antifoaming agent, a pH adjuster, an antioxidant, and an antiseptic can be added to the ink as long as the properties of the ink are not adversely affected.

The charge density Cd value of the black ink and the color ink is not particularly limited, but can be appropriately controlled as long as the difference “Cdk−Cd2” between the black ink and the color ink satisfies 80 μeq / g or more.
For example, the charge density Cd value of the black ink may be 500 μeq / g or less, preferably 400 μeq / g or less, more preferably 300 μeq / g or less. Further, the charge density Cd value of the black ink may be 90 μeq / g or more, or 100 μeq / g or more.

  The charge density Cd value of the color ink may be 400 μeq / g or less, preferably 200 μeq / g or less, more preferably 150 μeq / g or less. Further, the charge density Cd value of the color ink may be 10 μeq / g or more, or 20 μeq / g or more.

  The viscosity of the ink is preferably 1 to 30 mPa · s, and more preferably 2 to 15 mPa · s, from the viewpoint of dischargeability of inkjet printing. The inks constituting the ink set preferably have the same ink viscosity in order to print using the ink jet nozzles having the same structure. Therefore, the viscosity of each ink constituting the ink set is more preferably 2 to 15 mPa · s.

  The surface tension of the ink is preferably 30 to 50 mN / m at 25 ° C. In order to control the penetration of the ink, for example, there is a method of controlling the surface tension of the ink to adjust the penetration speed into the substrate. When the surface tension of the ink is 30 mN / m to 50 mN / m, it is easy to form an ink film due to a good ink permeation rate, and it is easy to obtain good ejection properties from an inkjet nozzle.

  The method for producing the ink is not particularly limited, and can be appropriately produced by a known method. For example, it can be prepared by adding or dispersing all components in a known disperser such as a bead mill in a lump or divided and passing through a known filter such as a membrane filter if desired. For example, after preparing a mixed liquid in which the whole amount of water and the coloring material is uniformly mixed and dispersing with a disperser, add the remaining components to this dispersion and prepare by passing through a filter. Can do.

<Surface treatment solution>
The ink set can further include a surface treatment liquid.
This surface treatment liquid is preferably applied as a pretreatment agent to the surface of the humidity control substrate before being decorated with an ink set in order to obtain a high-quality decorated part. Here, “application” means that the surface treatment liquid is attached to the object by any means such as coating.
As the surface treatment liquid, one containing water and inorganic particles and / or a water-dispersible resin can be used, and preferably contains water, inorganic particles and a water-dispersible resin.

  By preliminarily attaching the surface treatment liquid to the humidity control substrate, it is possible to enhance the gloss, scratch resistance, and color developability of the ink-decorated portion. In particular, a porous substrate having a low moisture absorption and / or moisture content and / or a low average moisture content, for example, a low degree of humidity regulation, and a low-grade control as defined in JIS A 1470-1 (2014) and / or JIS A 1475 (2004). In the case of wet building materials, it is possible to obtain high color developability even with a small amount of ink, but if the amount of ink discharged per unit time is increased, ink overflow may occur, and image bleeding and ink accumulation may occur easily. . In addition to lowering the image quality, this ink reservoir can block part of the pores of the porous substrate and cause a decrease in humidity control performance. In such a case, it is preferable that the surface treatment liquid is applied (pretreatment) to the surface of the porous substrate before printing and dried.

  In the surface treatment liquid, water functions as a solvent for the surface treatment liquid. In addition to water, a water-soluble organic solvent may be used as a solvent for the surface treatment liquid. The details of the water and the aqueous organic solvent are as described in the above ink.

As the inorganic particles, inorganic particles having an average particle diameter (median diameter measured by a dynamic light scattering method) of 300 nm or less can be preferably used. When the average particle diameter of the inorganic particles exceeds 300 nm, the inorganic particles are put on the surface of the porous base material, the scratch resistance of the decorative image is lowered, and the transparency of the surface treatment portion is lowered. The difference in appearance between the surface-treated portion and the non-surface-treated portion becomes conspicuous, which is not preferable.
The amount of the inorganic particles (effective component amount) in the surface treatment liquid is preferably 0.8% by mass or more, more preferably 1.3% by mass or more, and 20% by mass or less. Is preferable, and it is more preferable that it is 10 mass% or less.

  Since the inorganic particles can block a part of the large pores of the porous substrate to reduce the surface roughness Ra, and can suppress the components in the ink from entering the pores of the porous substrate. Compared to the case where surface treatment is not performed, the surface of the porous substrate becomes smooth, the uniformity of the dots of the image formed on the surface is improved, and the gloss of the resin contained in the ink or surface treatment liquid It is considered that the property can be expressed well. On the other hand, since only a part of the large pores of the porous substrate is blocked, the humidity control property is not lowered. Note that even if the surface of the porous substrate is simply polished to reduce the surface roughness Ra (arithmetic mean roughness), an effect corresponding to the effect obtained by the surface treatment cannot be obtained.

  Examples of the inorganic particles include silica fine particles, vermiculite, calcium carbonate, alumina and the like, and among them, silica fine particles are preferable. It is also preferable to use extender pigments such as talc, diatomaceous earth, calcium carbonate, barium carbonate, barium sulfate, alumina white, silica, kaolin, mica, acid clay, activated clay, bentonite and the like. These fine particles can be used alone or in combination of two or more.

  In the surface treatment liquid, the water dispersible resin is contained in order to sufficiently fix the inorganic particles to the porous substrate. Although it will not specifically limit if adhesiveness with a porous base material, etc. can be ensured, Specifically, various water dispersible resin described about the said ink can be used. A plurality of water-dispersible resins can also be used in combination.

  The blending amount of the water-dispersible resin in the surface treatment liquid is preferably 15: 1 to 50: 1 (mass ratio) in terms of the ratio of the inorganic particles to the water-dispersible resin (the inorganic particles: water-dispersible resin). By setting the amount of the water dispersible resin within this range, the inorganic particles can be sufficiently fixed on the porous substrate.

In the surface treatment liquid, the water-dispersible resin is present in the form of particles, and the average particle diameter of the particles is preferably larger than the diameter of the mesopores of the porous substrate to be decorated, specifically, , Larger than 40 nm, preferably 45 nm or more, more preferably 80 nm or more, and further preferably 150 nm or more. The upper limit of the average particle diameter is not particularly limited, but is preferably about 300 nm or less, more preferably 250 nm or less as a size suitable for inkjet printing.
The amount of the water-dispersible resin contained in the surface treatment liquid may be smaller than the amount of the water-dispersible resin in the ink.

The surface treatment liquid may contain a dispersion aid. The dispersion aid can further improve the dispersion stability of the inorganic particles and the water-dispersible resin in the surface treatment liquid. Further, the charge density Cd value of the surface treatment liquid can be adjusted by the dispersion aid, and the difference in charge density “| Cdk−Cdp |” between the black ink and the surface treatment liquid can be controlled to 200 μeq / g or less. .
As the dispersion aid, those common to the ink can be used, and the details are as described in the above-mentioned ink. In the ink set, the dispersion aid contained in the ink and the dispersion aid may be the same or different.
The dispersion aid can be blended in an amount of 0.1 to 10% by mass relative to the total amount of the surface treatment liquid, and may be 0.5 to 5% by mass.

The charge density Cd value of the surface treatment liquid is not particularly limited, but can be appropriately controlled as long as the difference “| Cdk−Cdp |” of the charge density between the black ink and the surface treatment liquid satisfies 200 μeq / g or less.
For example, the charge density Cd value of the surface treatment liquid may be 500 μeq / g or less, preferably 300 μeq / g or less, more preferably 200 μeq / g or less. Further, the charge density Cd value of the surface treatment liquid may be 10 μeq / g or more, or 20 μeq / g or more.

  As long as the surface treatment liquid does not adversely affect the properties of the surface treatment liquid, in addition to the above components, for example, other moisturizers, antifoaming agents, pH adjusters, antioxidants, preservatives, surfactants and the like Ingredients can be added.

  For the surface treatment liquid, water, water-dispersible resin, and inorganic particles are dispersed in a known disperser such as a bead mill, all at once or divided, and if desired, a known filtration such as a membrane filter can be used. It can be prepared by passing through a machine. For example, after preparing a mixed solution in which water and the whole amount of the above inorganic particles are uniformly mixed in advance and dispersing with a disperser, the remaining components are added to this dispersion and the mixture is passed through a filter. be able to.

<Manufacturing method of decorated humidity control substrate>
The manufacturing method of the decorated humidity control base material by one Embodiment includes the process of carrying out inkjet printing on a humidity control base material using the above-mentioned water-based inkjet ink set for humidity control base materials, It is characterized by the above-mentioned. Thereby, the decorating article which has a decorating image on the surface of a humidity control base material can be obtained.
Moreover, you may include the process of making the said surface treatment liquid adhere to a humidity-control base material before inkjet printing using an ink set.

  The surface treatment liquid may be attached to the surface of the porous substrate by applying it uniformly to the surface of the porous substrate using a brush, roller, bar coater, air knife coater, spray, or You may perform by printing an image with printing means, such as inkjet printing, gravure printing, and flexographic printing. That is, the surface treatment liquid may be applied to the entire surface of the porous substrate, or may be applied only to a necessary portion, for example, a portion where ink jet printing using the ink set is performed.

  The coating amount (attachment amount) of the surface treatment liquid varies depending on the moisture absorption / release amount and the average moisture content of the porous substrate, but in order to achieve a certain coloration and gloss of the decorated image, It is preferable to increase the coating amount (solid content) as the moisture absorption / release amount and the average moisture content are lower. In the case of a porous substrate having a surface roughness Ra of about 15 μm, printing is performed when a sufficient amount of the surface treatment solution is applied so that Ra after the surface treatment is preferably 10 μm or less, more preferably 8 μm or less. This is preferable because the color developability and glossiness of the image are improved.

Although the preferable coating amount of the surface treatment liquid varies depending on the humidity conditioning performance of the porous substrate as described above, it cannot be uniformly defined. However, as the solid content amount per coated area, for example, a first-class humidity conditioning building material If ^15g / ^{m 2 ~30g} / m 2 approximately, secondary ^5g / ^{m 2 ~15g} / m 2 about the case of the humidity control construction material, in the case of tertiary humidity building ^material, 3 g / m 2 to 10 g / it can be m ² approximately.

  The porous substrate after coating the surface treatment liquid is preferably subjected to printing with an ink set after drying moisture. This drying may be performed by heating the porous substrate to 100 to 200 ° C.

Inkjet printing for forming a decorative image on a porous substrate using an ink set can be performed using a general inkjet head, and there is no particular limitation on the printing method, the apparatus used, and the like. The inkjet printing method may be a piezo method, an electrostatic method, a thermal method, or the like.
The porous substrate after the decorative image is formed by the ink set is dried at 100 to 200 ° C. in order to dry the moisture and quickly fix the coloring material and the resin component to the porous substrate. You may heat to.
In this way, a decorative article having a decorative image mainly composed of a color material and a resin component, for example, a decorative building material can be obtained.

  When ink-jet printing is performed on a porous substrate using an ink set, in order to obtain a high-quality decorative image, (i) the ink droplets are reduced, (ii) the printing speed is decreased, (iii) one-way It is effective to use printing conditions such as printing, (iv) printing while warming the porous substrate, (v) reducing the printing resolution, or (vi) printing by combining these methods. . In particular, a porous substrate having a low moisture absorption / release amount and / or an average moisture content, for example, a humidity control building material having a low humidity control property and a low grade specified in the humidity control performance evaluation criteria of the humidity control building material (for example, the above-mentioned In the case of first-class humidity control building materials), image bleeding and ink accumulation are likely to occur unless surface treatment is applied, but by employing the above method, image bleeding and ink accumulation are avoided even without surface treatment. Can do.

(Iv) The printing condition for printing while warming the porous substrate is that the porous substrate has many irregularities when it is necessary to obtain a high color image with a small amount of ink regardless of the performance of the porous substrate. It is also effective as a printing condition in the case of uniformly printing a pattern that straddles a plurality of porous substrates having different water absorption performance of ink. By printing while warming the porous substrate, it is possible to form the presence of pigments and other components other than water in the ink near the surface of the porous substrate. The influence on the wet performance and shape is reduced, and a stable image can be obtained.
The method for warming the porous substrate is arbitrary, and the heating temperature is not particularly limited as long as the nozzle used for inkjet printing is dried and the discharge does not become unstable. For example, the heating can be performed in the range of 50 to 100 ° C.

  The apparatus for forming the decorative image is not particularly limited. For example, the placement unit for placing the porous substrate and the inkjet printing by discharging ink onto the surface of the porous substrate. A surface treatment liquid application unit for applying a surface treatment liquid to the surface of the porous substrate, and / or a heating unit for heating the porous substrate. Can be used.

  More specifically, the decoration device includes an input unit (for example, a scanner) for providing electronic data of an image to be decorated (having a pixel value corresponding to each pixel), the surface of the porous substrate An inkjet head unit that records an image by ejecting water-based ink onto the substrate, and a conveyance unit that conveys the porous substrate to a position facing the ejection nozzle formed on the lower surface of the inkjet head unit with the porous substrate placed thereon And before the porous substrate reaches the ink jet head unit, a surface treatment liquid coating unit is provided for discharging the surface treatment liquid onto the surface of the porous substrate and coating the surface treatment liquid on the porous substrate. Can do. Furthermore, a heating unit (various heaters such as a ceramic heater) for heating the decorative region on the porous substrate is provided during printing or at any stage before and after printing, and the discharged surface treatment liquid and / or ink is dried. It is preferable to be able to promote.

Before decorating with an ink set, or when performing surface treatment, the porous substrate before coating with the surface treatment liquid, that is, the untreated porous substrate is flattened by polishing the surface or the like. It is preferable. Thereby, the coloring property and glossiness of the printed decorative image can be further improved.
Specifically, the untreated porous substrate preferably has a surface roughness Ra of about 10 μm or less, more preferably 8 μm or less. The surface roughness Ra can be measured by “Laser Scanning Microscope VK-8700” manufactured by KEYENCE. In the measurement, specific parts such as large irregularities and missing parts of the porous substrate may be excluded.

  In the case of a humidity control building material produced by a carbonic acid curing reaction as described in JP-A-2002-4447, it is usually produced and decorated in the following steps: mixing of raw materials, press molding, carbon dioxide gas curing (exothermic heat), and drying. A process is performed with respect to a carbon dioxide gas hardening body, and specifically, it is performed in the process of carbon dioxide gas hardening body-> decorative printing-> heating-> natural cooling (completion). In one embodiment, the decoration can be performed on the humidity-controlled building material with respect to the carbon dioxide cured body. However, in another embodiment, the molded product before the carbon dioxide gas curing after press molding is performed. Even decoration can be performed. In the latter case, decorative building materials can be manufactured in the process of material mixing-> press molding-> decorative printing-> carbon dioxide curing (exotherm)-> drying (completion), so use the heat from the carbon dioxide curing process and the drying process. Thus, water and other volatile components of the ink can be volatilized, energy consumption can be kept low, the process can be shortened, and the stock stock before decoration can be eliminated.

<Decorated humidity control substrate>
The decorated humidity conditioning substrate (decorated article) has a decorated image formed using the aqueous inkjet ink set for the humidity conditioning substrate, and is measured according to JIS A 1470-1 (2014). It has a moisture conditioning function in which the amount of moisture absorption after 3 hours is greater than 15 g / m ² .
For example, the decorative article is preferably a humidity-controlled building material, but may be a coaster, a foot-wiping mat or the like in addition to the building material.

The decorative image formed by inkjet printing is preferably one that has been previously surface-treated with the above-described surface treatment liquid, that is, formed on the surface of the porous substrate to which the surface treatment liquid has adhered.
The recording area of the decorative image is not particularly limited, and an arbitrary picture or character or a combination of a picture and a character can be freely selected.

A series of embodiments of the present invention will be described below, but the present invention is not limited thereto.
[1] A water-based inkjet ink set for a humidity control substrate, comprising a black water-based ink and a water-based ink other than black, wherein the charge density of the black water-based ink is 80 μeq / g or more higher than the charge density of the water-based ink other than black .
[2] At least one of the black water-based ink and the non-black water-based ink includes a color material, a water-dispersible resin, and water, and the water-dispersible resin includes a water-dispersible urethane resin and a water-dispersible ( The water-based inkjet ink set for a humidity control substrate according to [1], comprising at least one selected from the group consisting of a (meth) acrylic resin and a water-dispersible styrene / (meth) acrylic resin.

[3] The method according to [1] or [2], further comprising a surface treatment liquid, wherein an absolute value of a difference between the charge density of the black aqueous ink and the charge density of the surface treatment liquid is 200 μeq / g or less. A water-based inkjet ink set for humidity control substrates.
[4] The water-based inkjet ink set for a humidity control substrate according to [3], wherein the surface treatment liquid includes inorganic particles, a water-dispersible resin, and water.

[5] A decorated humidity control substrate comprising a step of performing inkjet printing on a humidity control substrate using the water-based inkjet ink set for a humidity control substrate according to any one of [1] to [4] Production method.
[6] including a step of performing inkjet printing on the humidity control substrate using the aqueous inkjet ink set for a humidity control substrate according to [3] or [4], and attaching the surface treatment liquid to the humidity control substrate A method for producing a decorated humidity control substrate, wherein after the ink-jet ink set is used, inkjet printing is performed on the humidity control substrate using the aqueous inkjet ink set.
[7] A decorative image formed using the water-based inkjet ink set for a humidity control substrate according to any one of [1] to [4], and measured according to JIS A 1470-1 (2014) 3 A decorated humidity control substrate having a moisture absorption after time of more than 15 g / m ² .

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited only to these Examples.

<Manufacture of water-based ink>
Table 2 shows black (K) ink, Table 3 shows cyan (C) ink, and Table 4 shows magenta (M) and yellow (Y) ink.
Each component shown in each table was premixed in the ratio shown in each table, then dispersed for 1 minute by a homogenizer, and the obtained dispersion was passed through a membrane filter having a pore size of 3 μm to obtain inks 1 to 17.

Details of the raw materials in each table are as follows.
(Pigment dispersion / pigment)
BONJET BLACK CW-6: A self-dispersing carbon black dispersion manufactured by Orient Chemical Industry Co., Ltd.
BONJET BLACK CW-2: Self-dispersing carbon black dispersion manufactured by Orient Chemical Co., Ltd.
CAB-O-JET 450C: a cyan self-dispersing pigment dispersion manufactured by Cabot Corporation.
CAB-O-JET 465M: Magenta self-dispersing pigment dispersion manufactured by Cabot Corporation.
Smart Magenta 3122BA :: Magenta pigment dispersion manufactured by SENSIJET.
CAB-O-JET 470Y: Yellow self-dispersing pigment dispersion manufactured by Cabot Corporation.
Fastogen Blue TGR: Cyan pigment manufactured by DIC Corporation.
Cinquasia Magenta D4550J: Magenta pigment manufactured by BASF.
Inkjet Yellow 4GP: Yellow pigment manufactured by Clariant.

(Dispersant)
TEGO Dispers 760W: a styrene maleic acid-based dispersant manufactured by Evonic.
TEGO Dispers 757W: a polymer dispersant manufactured by Evonic.
DISPERBYK-102: Dispersant manufactured by BYK.
FUJI SP A-54: an acrylic dispersant manufactured by Fuji Color Co., Ltd.

(Water dispersible resin)
Superflex 460S: manufactured by Daiichi Kogyo Seiyaku Co., Ltd., self-emulsifying water-based urethane resin (average particle size 56 nm).
Superflex 300: manufactured by Daiichi Kogyo Seiyaku Co., Ltd., urethane-based water-dispersible resin (average particle size 40 nm).
Adekabon titer HUX-370: ADEKA Corporation, a self-emulsifying water-based urethane resin (average particle size 10 nm).
Mobile 966A: Nippon Synthetic Chemical Industry Co., Ltd., anionic aqueous acrylic resin emulsion (average particle size 170 nm).
NeoCryl BT-62: a styrene acrylic water-dispersible resin (average particle diameter of less than 100 nm) manufactured by DSM.
Takelac XW-75-W932 (acid value 80): a urethane resin emulsion manufactured by Mitsui Chemicals, Inc.
Takelac W 5661 (acid value 48): manufactured by Mitsui Chemicals, urethane resin emulsion.
(Solvent) Water: Ion exchange water.
(Water-soluble solvent) Diethylene glycol: manufactured by Wako Pure Chemical Industries, Ltd.
(Activator) Surfynol 465: Nissin Chemical Industry Co., Ltd., acetylene glycol surfactant.

The average particle size of the resin was determined by using a dynamic light scattering particle size distribution measuring device “nano particle analyzer nano Prica SZ-100” (manufactured by HORIBA, Ltd.) with each resin dispersion having a particle concentration of 0. Dilute with purified water to 5% by mass and measure the dispersion medium refractive index: 1.333, sample refractive index: 1.600, calculation condition: polydispersion / narrow, and measured at a temperature of 25 ° C. Is the median diameter.
In each table, the column of “active ingredient” indicates the ratio of the nonvolatile content or solid content of each component, and the amount of active ingredient of each component is indicated in parentheses in the table.

<Manufacture of surface treatment liquid>
Table 5 shows the formulation of the surface treatment liquid.
Each component shown in the table was premixed at the ratio shown in the table, and then dispersed for 1 minute by an ultrasonic disperser to obtain surface treatment liquids 1 and 2.
Details of the raw materials in the table are as follows.
Aerosil OX-50: manufactured by Nippon Aerosil Co., Ltd., hydrophilic fumed silica (primary particle size 40 nm).
Sumilite 1010: manufactured by Sumika Chemtex Co., Ltd., ethylene-vinyl chloride copolymer resin emulsion (average particle size 200 nm).
FUJI SP A-54: an acrylic dispersant manufactured by Fuji Color Co., Ltd.

<Evaluation>
The charge density of each of the inks of K, C, M, and Y and the surface treatment liquid was measured by the following procedure. The charge density is also shown in Tables 2 to 5.
The following evaluation was performed using an ink set in which the inks of the respective colors K, C, M, and Y and the surface treatment liquid were combined. Tables 6 and 7 show combinations of ink sets and evaluation results.

(Measurement of charge density)
The charge density (Cd) of each ink and surface treatment liquid was measured by the streaming potential method. The charge density was measured using a colloidal particle charge meter (“Model CAS” manufactured by AFG ANALYTIC GmbH). The ink and surface treatment liquid to be measured were each diluted 100-fold with ion-exchanged water, and the sample was 0.0025 N Titration is performed with a polydiallyldimethyl-ammonium chloride (polyDADMAC) solution (manufactured by Wako Pure Chemical Industries, Ltd.), the reaction end point at which the streaming potential becomes 0 V is measured, and the total charge of the ink is determined from the amount of polyDADMAC used up to the reaction end point. The charge density (μeq / g) was determined from the total charge amount of the ink per active ingredient amount in the diluted ink.
The charge density of the K ink is represented as Cdk, the maximum charge density of the C ink, the M ink, and the Y ink is represented as Cd2, and the charge density of the surface treatment liquid is represented as Cdp. Tables 6 and 7 show calculated values of “Cdk-Cd2” and “Cdk-Cdp”.

(Preparation of printed matter)
Commercially available humidity conditioning building materials (thickness 6mm, surface roughness Ra15μm, surface) with mesopores and macropores as the printing substrate, with moisture absorption / release amounts of grade 3 and equilibrium moisture content of grade 3 60 ° glossiness of 2.5; “Mois” manufactured by Aika Industry Co., Ltd.). The surface of the humidity control building material was polished until the surface roughness was Ra 8 μm.
For printing, a textile printer “MMP8130” manufactured by Mastermind was used.
Ink combinations of inks shown in Table 6 and Table 7 are used to introduce K, C, M, and Y color inks into the printer, and C, M, and Y stripes are formed on the humidity control building material. A fine print of K and a solid image were formed thereon to obtain a printed matter.
The striped pattern of C, M, and Y is a striped pattern in which a C band having a length of 2 mm, a C band having a length of 120 mm, an M band, and a Y band are repeatedly arranged in this order without a gap. On this striped pattern, a K fine character of font 6 and a solid image of K of size 10 mm × 10 mm were printed so as to overlap each color of C, M, and Y.
After printing, the obtained image was heat-fixed at 160 ° C. for 60 seconds.
In Examples other than Examples 3 and 6 and Comparative Example 2, surface treatment was performed before printing.
When the surface treatment is performed, the surface treatment solution 1 or 2 is applied to the entire surface of the base material by a commercially available air spray at a wet coating amount of 78 g / m ² (solid content of about 6.2 g / m ² ), 110 After heating for 2 hours on a sheet heater at 0 ° C., printing was performed by the above method.

The following evaluation was performed about the obtained printed matter.
(Color mixing / smearing)
Color mixing and blurring were evaluated according to the following evaluation criteria by observing the blurring of the K-shaped edge of the printed matter with a microscope.
AA: The characters are not blurred.
A: The characters have a slight blur but are hardly understood.
B: The characters are slightly blurred but not noticeable.
C: Characters are blurred and noticeable.
D: The characters are blurred.

(Glossiness)
The 60 ° glossiness of the K solid image partial surface of the obtained printed matter and the humidity-controlled building material (material) before printing is measured with “Multi-Gloss 268” manufactured by Konica Minolta, and the glossiness before and after printing is measured according to the following criteria: evaluated.
A: It is higher than the material.
B: Same as the material.
C: Inferior to the material.

(Color development (K))
The OD value of the surface of the solid image portion of K of the obtained printed matter was measured, and the color developability (K) was evaluated according to the following criteria. For measurement of the OD value, “X-Rite eXact” manufactured by X-Rite was used.
A: The OD value exceeds 1.07.
B: OD value is 1.02-1.07.
C: The OD value is less than 1.02.

(Abrasion resistance)
The surface of the solid image portion of K of the obtained printed material was rubbed with a dry sponge, and scratch resistance was evaluated according to the following criteria.
AA: The image is not peeled even after 50 times of rubbing with a sponge.
A: The image is peeled off by rubbing with a sponge 30 times or more and less than 50 times.
B: The image is peeled off by rubbing with a sponge 10 times or more and less than 30 times.
C: The image is peeled off by rubbing with a sponge less than 10 times.

As shown in each table, each of the evaluation results was good in the decorative and humidity-controlled building material of each example.
In Examples 2 and 9, the difference between Cdk and Cd2 was large, and color mixing and bleeding were further improved.
In Examples 1, 2, and 9, the difference in Cdk-Cdp was small, and the color development and scratch resistance were further improved. In particular, in Example 1, the result of scratch resistance was good.
Through Examples 3-6, it can be seen that the glossiness and scratch resistance are improved by using the surface treatment liquid. In Example 10, the charge density Cdk of the black ink was smaller than the charge density Cdp of the surface treatment liquid, but the absolute value of Cdk-Cdp was small, and the color development and scratch resistance were further improved.
Moreover, when the moisture absorption / release amount of JIS A 1470-1 (2014) and the equilibrium moisture content of JIS A 1475 (2004) were measured for the decorative moisture-conditioning building materials obtained in each example, all examples The grades of all items were maintained.

In each of the comparative examples, the difference of Cdk-Cd2 was 68 μeq / g or less, and color mixing / bleeding and color development deteriorated.
In Comparative Example 2, no surface treatment solution was used, and each evaluation was bad.
In Comparative Example 3, the difference between Cdk and Cdp was more than 200 μeq / g, and the scratch resistance was further lowered.
In Comparative Example 5, there is a large difference in acid value between the water-dispersible resin used for the black ink and the water-dispersible resin used for the cyan ink having the second highest Cd value, but the difference in Cdk−Cd2 is It was as small as 22 μeq / g, and color mixing / bleeding was not improved.

Claims (7)

  A water-based inkjet ink set for a humidity control substrate, comprising a black water-based ink and a water-based ink other than black, wherein the charge density of the black water-based ink is 80 μeq / g or more higher than the charge density of the water-based ink other than black. At least one of the black aqueous ink and the non-black aqueous ink contains a color material, a water-dispersible resin, and water,
The water dispersible resin is
The humidity control substrate according to claim 1, comprising at least one selected from the group consisting of a water dispersible urethane resin, a water dispersible (meth) acrylic resin, and a water dispersible styrene / (meth) acrylic resin. Water-based inkjet ink set.   The humidity control substrate according to claim 1, further comprising a surface treatment liquid, wherein an absolute value of a difference between a charge density of the black aqueous ink and a charge density of the surface treatment liquid is 200 μeq / g or less. Water-based inkjet ink set.   The water-based inkjet ink set for a humidity control substrate according to claim 3, wherein the surface treatment liquid contains inorganic particles, a water-dispersible resin, and water.   The manufacturing method of the decorated humidity control base material including the process of performing inkjet printing on a humidity control base material using the water-based inkjet ink set for humidity control base materials of any one of Claim 1 to 4.   A step of performing inkjet printing on the humidity control substrate using the water-based inkjet ink set for a humidity control substrate according to claim 3 or 4, wherein the surface treatment liquid is attached to the humidity control substrate, The manufacturing method of the decorated humidity control base material which inkjet-prints on the said humidity control base material using an aqueous inkjet ink set. A decorative image formed using the water-based inkjet ink set for a humidity control substrate according to any one of claims 1 to 4, and after 3 hours measured according to JIS A 1470-1 (2014) A decorated moisture conditioning substrate having a moisture absorption greater than 15 g / m ² .