CN111094474A - Near-infrared-curable ink composition, near-infrared-curable film, method for producing near-infrared-curable film, and method for photo-molding - Google Patents

Abstract

The present invention provides a composition containing a compound having sufficient infrared absorptionAn infrared-curable ink composition containing composite tungsten oxide fine particles having excellent capability and adhesion to a substrate, a near-infrared-curable film, and a stereolithography method using the near-infrared-curable ink composition. A near-infrared-curable ink composition comprising composite tungsten oxide fine particles having a near-infrared-absorbing ability and an uncured thermosetting resin, wherein the composite tungsten oxide fine particles are composite tungsten oxide fine particles having a hexagonal crystal structure, and the a-axis of the lattice constant of the composite tungsten oxide fine particles is

Above and

in the following, the c-axis is

Above and

Description

Near-infrared-curable ink composition, near-infrared-curable film, method for producing near-infrared-curable film, and method for photo-molding

Technical Field

The present invention relates to a near-infrared curable ink composition, a near-infrared curable film, a method for producing the same, and a method for stereolithography.

Background

The ultraviolet-curable coating material cured by ultraviolet rays can be printed without heating. Therefore, in recent years, it has been widely known as an environment-compatible coating material, and patent documents 1to 6, for example, have been proposed or disclosed.

However, according to the discussion of the present inventors, when a composition that is radical-polymerized by ultraviolet irradiation is used as an ultraviolet-curable ink or coating, the presence of oxygen hinders polymerization (curing). On the other hand, when a composition that is cationically polymerized by ultraviolet irradiation is used, there is a technical problem that strong acid is generated in the polymerization.

In order to improve the light resistance of the printed surface or coated surface, an ultraviolet absorber is generally added to the printed surface or coated surface. However, when an ultraviolet absorber is added to an ultraviolet-curable ink or paint, there is a technical problem of inhibiting curing by ultraviolet irradiation.

In order to solve the above-mentioned problems, patent documents 7 and 8 propose near-infrared ray-curable compositions which are cured by irradiation with near-infrared rays without using ultraviolet rays.

Further, the present applicant disclosed in patent document 9 a near-infrared curable ink composition containing a composite tungsten oxide.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 7-100433

Patent document 2: japanese patent No. 3354122

Patent document 3: japanese patent No. 5267854

Patent document 4: japanese patent No. 5626648

Patent document 5: japanese patent No. 3494399

Patent document 6: japanese patent laid-open No. 2004-18716

Patent document 7: japanese patent No. 5044733

Patent document 8: japanese patent laid-open publication No. 2015-131928

Patent document 9: international publication No. 2017/047736

Disclosure of Invention

Technical problem to be solved by the invention

However, according to further discussion by the inventors of the present invention, the near-infrared ray-curable compositions described in patent documents 7 and 8 have a technical problem that the near-infrared ray absorption characteristics are not sufficient.

On the other hand, the market demands for near infrared ray-curable compositions are increasing. For example, even the near-infrared ray curable ink composition or the near-infrared ray curable film containing the composite tungsten oxide described in patent document 9 is considered to be difficult to continuously satisfy the market demand for improvement of adhesion to a substrate.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide: a near-infrared ray-curable ink composition which is provided on a predetermined substrate and is cured by irradiation with near-infrared rays, a near-infrared ray-curable film obtained by curing the near-infrared ray-curable ink composition, a method for producing the near-infrared ray-curable ink composition, and a method for stereolithography using the near-infrared ray-curable ink composition.

Means for solving the problems

In order to solve the technical problems, the inventors of the present invention have conducted studies and, as a result, have conceived that: it is effective to improve the near-infrared ray absorption ability of the composite tungsten oxide fine particles and to improve the amount of heat generated when the near-infrared ray curable ink composition is irradiated with near-infrared rays. Then, the heat generation amount is increased to increase the degree of curing of the ink composition, thereby improving the adhesion to the substrate.

That is, the 1 st invention for solving the technical problem is as follows:

a near-infrared ray-curable ink composition comprising composite tungsten oxide fine particles having near-infrared ray absorbing ability and an uncured thermosetting resin, wherein,

the composite tungsten oxide fine particles are composite tungsten oxide fine particles containing a hexagonal crystal structure,

the a-axis of the lattice constant of the composite tungsten oxide fine particles is

Above and

in the following, the c-axis is

Above and

in the following, the following description is given,

the composite tungsten oxide fine particles have an average particle diameter of 100nm or less.

The invention of claim 2 is as follows:

the near-infrared-curable ink composition according to claim 1, wherein the a-axis of the lattice constant of the composite tungsten oxide fine particles is

Above and

in the following, the c-axis is

Above and

the following.

The invention 3 is as follows:

the near-infrared-curable ink composition according to claim 1 or 2, wherein the composite tungsten oxide fine particles have an average particle diameter of 10nm or more and 100nm or less.

The 4 th invention is as follows:

the near-infrared curable ink composition according to any one of claims 1to 3, wherein the composite tungsten oxide fine particles have a crystallite diameter of 10nm or more and 100nm or less.

The invention of claim 5 is as follows:

the near-infrared curable ink composition according to any one of claims 1to 4, further comprising a dispersant.

The 6 th invention is as follows:

the near-infrared curable ink composition according to any one of claims 1to 5, further comprising a solvent.

The 7 th invention is as follows:

the near-infrared curable ink composition according to any one of claims 1to 6, wherein the composite tungsten oxide is represented by the general formula MxWyOz (wherein M is at least 1 element selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb, W is tungsten, O is oxygen, and x/y is 0.001. ltoreq. x/y.ltoreq.1, and z/y is 2.0. ltoreq. z/y.ltoreq.3. 0).

The 8 th invention is as follows:

the near-infrared curable ink composition according to claim 7, wherein the composite tungsten oxide contains 1 or more composite tungsten oxides in which M element is selected from Cs and Rb.

The 9 th invention is as follows:

the near-infrared curable ink composition according to any one of claims 1to 8, wherein at least a part of the surface of the composite tungsten oxide fine particles is coated with a surface coating film, and the surface coating film contains at least 1 or more elements selected from Si, Ti, Zr, and Al.

The 10 th invention is as follows:

the near-infrared curable ink composition according to claim 9, wherein the surface coating film contains an oxygen atom.

The 11 th invention is as follows:

the near-infrared curable ink composition according to any one of claims 1to 10, further comprising 1 or more selected from the group consisting of an organic pigment, an inorganic pigment and a dye.

The 12 th invention is as follows:

a near-infrared ray-curable film obtained by curing the near-infrared ray-curable ink composition according to any one of claims 1to 11 by irradiation with near-infrared rays.

The 13 th invention is as follows:

a method of light sculpting, comprising: the near-infrared ray-curable ink composition according to any one of claims 1to 11 is applied to a substrate to prepare a coated product, and the coated product is irradiated with near-infrared rays to be cured.

The 14 th invention is as follows:

a process for producing a near-infrared-curable ink composition comprising composite tungsten oxide fine particles having near-infrared absorption ability, an uncured thermosetting resin, a dispersant and a solvent, wherein,

the composite tungsten oxide fine particles are composite tungsten oxide fine particles containing a hexagonal crystal structure,

the method comprises the following steps: the composite tungsten oxide fine particles are produced so that the lattice constant thereof is on the a-axis

Above and

in the following, the c-axis is

Above and

the following ranges are set forth below,

and a pulverization and dispersion treatment step of maintaining the range of the lattice constant of the composite tungsten oxide fine particles and making the average particle diameter of 100nm or less.

The 15 th invention is as follows:

the method for producing a near-infrared-curable ink composition according to claim 14, wherein the composite tungsten oxide is represented by a general formula MxWyOzz (M is at least 1 element selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb, W is tungsten, O is oxygen, and x/y is 0.001. ltoreq. x/y.ltoreq.1, and z/y is 2.0. ltoreq. z/y.ltoreq.30).

The 16 th invention is as follows:

the method for producing a near-infrared-curable ink composition according to claim 14 or 15, wherein the composite tungsten oxide contains a composite tungsten oxide in which the M element is 1 or more selected from Cs and Rb.

The 17 th invention is as follows:

the method for producing a near-infrared-curable ink composition according to any one of claims 14 to 16, wherein at least a part of the surface of the composite tungsten oxide fine particles is coated with a surface coating film containing 1 or more elements selected from Si, Ti, Zr, and Al.

The 18 th invention is as follows:

the method for producing a near-infrared-curable ink composition according to claim 17, wherein the surface coating film contains an oxygen atom.

The 19 th invention is as follows:

the method for producing a near-infrared-curable ink composition according to any one of claims 14 to 18, wherein the near-infrared-curable ink composition further contains at least one kind selected from the group consisting of an organic pigment, an inorganic pigment and a dye

Drawings

Fig. 1 is a conceptual diagram of an apparatus according to an embodiment of a high-frequency thermal plasma reaction apparatus used for producing composite tungsten oxide fine particles of the present invention.

Detailed Description

The following describes in detail [1] a near-infrared ray-curable ink composition, [2] a near-infrared ray-curable film, and a stereolithography method in order for the near-infrared ray-curable ink of the present invention and the stereolithography method using the same.

[1] Near-infrared curable ink composition

The near-infrared-curable ink composition of the present invention contains composite tungsten oxide fine particles having near-infrared absorption ability, an uncured thermosetting resin, and other components added as needed. Accordingly, the following description sequentially describes [ a ] composite tungsten oxide fine particles, [ b ] a method for synthesizing composite tungsten oxide fine particles, [ c ] an uncured thermosetting resin, [ d ] other components, and [ e ] a near-infrared ray curable ink composition.

[a] Composite tungsten oxide fine particles

As the near-infrared ray absorbing fine particles used in the near-infrared ray curable ink composition, composite tungsten oxide fine particles are exemplified, and carbon black powder or tin-added indium oxide (in the present invention, sometimes referred to as "ITO") powder is considered. However, when carbon black powder is used as the near-infrared ray-absorbing fine particles, the degree of freedom in selecting the color of the near-infrared ray-curable ink composition is reduced because the powder is black. On the other hand, when ITO powder is used as the near-infrared ray absorbing fine particles, the near-infrared ray curable ink composition cannot exhibit curability unless a large amount of the powder is added. Therefore, when a large amount of the ITO powder is added, the powder is added in a large amount, which may adversely affect the color tone of the near-infrared curable ink composition.

In the near-infrared ray-curable film containing the near-infrared ray-absorbing fine particles, since coloring due to the near-infrared ray-absorbing fine particles is not preferable, it is conceivable that: in the present invention, the composite tungsten oxide fine particles that do not cause coloring due to the fine particles are contained as the near-infrared-absorbing fine particles.

When the composite tungsten oxide fine particles are made into near-infrared-absorbing fine particles, free electrons are generated in the composite tungsten oxide fine particles, and absorption characteristics from the free electrons are exhibited in the near-infrared region. As a result, the composite tungsten oxide fine particles are effective as near-infrared-absorbing fine particles having a wavelength of about 1000 nm.

The composite tungsten oxide fine particles of the present invention have a near-infrared absorption characteristic, and have a hexagonal crystal structure, and the a-axis of the lattice constant is

Above and

in the following, the c-axis is

Above and

the following.

In the composite tungsten oxide fine particles of the present invention, the value of [ c-axis lattice constant/a-axis lattice constant ] is preferably from 1.0221 to 1.0289.

Hereinafter, the composite tungsten oxide fine particles of the present invention are summarized as (1) crystal structure and lattice constant, (2) particle diameter and crystallite diameter, (3) composition of the composite tungsten oxide fine particles, (4) surface coating of the composite tungsten oxide fine particles, and (5) in this order.

(1) Crystal structure and lattice constant

The composite tungsten oxide fine particles of the present invention can be formed into a tetragonal or cubic alkali tungstate structure in addition to the hexagonal structure, and are effective as near-infrared absorbing materials in any structure. However, the absorption position in the near-infrared region tends to change depending on the crystal structure formed by the composite tungsten oxide fine particles. That is, the absorption position in the near infrared region tends to be as follows: the crystal is shifted to the longer wavelength side than the cubic crystal in the case of tetragonal crystal, and to the longer wavelength side than the tetragonal crystal in the case of hexagonal crystal. Further, as the absorption position varies, the absorption of light in the visible light region is minimized by hexagonal crystals and then by tetragonal crystals, with cubic crystals being maximized.

From the above, it has been found that hexagonal alkali tungstate is most preferably used for applications in which light in the visible light region is further transmitted and light in the near infrared region is further absorbed. When the composite tungsten oxide fine particles have a hexagonal crystal structure, the transmission of the fine particles in the visible light region is improved, and the absorption in the near infrared region is improved. In the hexagonal crystal structure, WO is added₆The 8-sided body formed by the unit is a hexagonal void (channel) composed of 6 groups, and M elements are arranged in the void to constitute one unit, and a plurality of the units are grouped to constitute a hexagonal crystal structure.

In the present invention, in order to obtain effects of improving the transmission in the visible light region and improving the absorption in the near infrared region, the composite tungsten oxide is usedThe substance particles contain unit structures (in WO)₆A structure in which 6 hexagonal voids are formed by collecting 8 bodies formed as a unit and M elements are arranged in the voids) may be used.

When a cation of an M element is added to the hexagonal voids, the absorption in the near infrared region is improved. Here, the hexagonal crystal is generally formed when the M element having a large ionic radius is added, and specifically, the hexagonal crystal is easily formed when 1 or more kinds selected from Cs, Rb, K, Tl, Ba, and In are added, which is preferable.

Further, in the composite tungsten oxide fine particles in which 1 or more kinds selected from Cs and Rb are added to the M element having a large ionic radius, both absorption in the near infrared region and transmission in the visible light region can be achieved.

When 2 or more elements are selected as the M element, one of them is selected from Cs, Rb, K, Tl, Ba and In, and the remaining is selected from 1 or more elements constituting the M element, hexagonal crystals may be formed.

When Cs tungsten oxide fine particles are selected as the M element, the lattice constant is preferably such that the a axis is

Above and

in the following, the c-axis is

Above and

the following; preferably the a axis is

Above and

in the following, the c-axis is

Above and

the following.

When Rb tungsten oxide fine particles in which Rb is selected as the M element, the lattice constant is preferably such that the a axis is

Above and

in the following, the c-axis is

Above and

the following.

When CsRb tungsten oxide fine particles in which Cs and Rb are selected as the M element, the lattice constant is preferably such that the a axis is

Above and

in the following, the c-axis is

Above and

the following.

However, the M element is not limited to the Cs or Rb. Even if the M element is an element other than Cs or Rb, the element is present in WO as an additive M element₆The unit may be formed in a hexagonal void.

When the composite tungsten oxide having a hexagonal crystal structure of the present invention is represented by the general formula MxWyOz, the amount of the M element added is 0.001. ltoreq. x/y.ltoreq.1, preferably 0.2. ltoreq. x/y.ltoreq.0.5, more preferably 0.20. ltoreq. x/y.ltoreq.0 when the composite tungsten oxide fine particles have a uniform crystal structure37, most preferably x/y is 0.33. The reason for this is considered to be that, theoretically, when z/y is 3, the additive M element is arranged in all the voids of the hexagonal shape when x/y is 0.33. As typical examples, there may be mentioned: cs_0.33WO₃、Cs_0.03Rb_0.30WO₃、Rb_0.33WO₃、K_0.33WO₃、Ba_0.33WO₃And the like.

The inventors of the present invention have made extensive studies on a countermeasure for further improving the near-infrared absorption function of the composite tungsten oxide fine particles, and have conceived of a configuration in which the amount of free electrons contained therein is further increased.

That is, as a measure for increasing the amount of free electrons, it is conceivable to apply mechanical treatment to the composite tungsten oxide fine particles to impart appropriate strain or deformation to the hexagonal crystal contained therein. In the hexagonal crystal to which an appropriate strain or deformation is applied, it is considered that the overlap state of the electron orbitals of the atoms constituting the microcrystalline structure changes, and the amount of free electrons increases.

Based on the idea, the inventors of the present invention have made studies on the following matters: in a dispersing step in producing a composite tungsten oxide fine particle dispersion from composite tungsten oxide particles produced in a firing step of "[ b ] a method for synthesizing composite tungsten oxide fine particles" described below, the composite tungsten oxide particles are pulverized under predetermined conditions to impart strain or deformation to the crystal structure, thereby increasing the amount of free electrons and further improving the near-infrared ray absorption function of the composite tungsten oxide fine particles.

Then, based on this study, the particles of the composite tungsten oxide produced in the firing step are discussed focusing on the respective particles. As a result, it was found that the lattice constant and the composition of the constituent elements were varied among the respective particles.

As a result of further studies, it was found that the composite tungsten oxide fine particles finally obtained exhibited desired optical characteristics when the lattice constant thereof was within a predetermined range, despite variations in the lattice constant or the composition of the constituent elements among the respective particles.

The inventors of the present invention, which have obtained the above-mentioned findings, further examined the optical properties exhibited by the fine particles by measuring the a-axis and c-axis that are lattice constants in the crystal structure of the fine particles of the composite tungsten oxide, and thereby grasping the degree of strain or deformation of the crystal structure of the fine particles.

Then, it was found from the results of the investigation that the hexagonal composite tungsten oxide fine particles had the a axis of the hexagonal composite tungsten oxide fine particles

Above and

in the following, the c-axis is

Above and

the fine particles are composite tungsten oxide fine particles exhibiting a maximum light transmittance in the wavelength range of 350nm to 600nm and a minimum light transmittance in the wavelength range of 800nm to 2100nm, and exhibiting an excellent near infrared ray absorption effect.

The a-axis of the composite tungsten oxide fine particles of the present invention is

Above and

in the following, the c-axis is

Above and

in the hexagonal composite tungsten oxide fine particles described below, particularly excellent near-infrared absorption effect is exhibited when the x/y value indicating the addition amount of the element M is in the range of 0.001. ltoreq. x/y. ltoreq.1, preferably in the range of 0.20. ltoreq. x/y. ltoreq.0.37.

In addition, it was found that the single crystal in which the amorphous phase volume ratio is 50% or less is preferable in the composite tungsten oxide fine particles.

It is considered that when the composite tungsten oxide fine particles are single crystals having an amorphous phase volume ratio of 50% or less, the lattice constant is maintained within the above-described predetermined range, and the crystallite diameter is set to 10nm or more and 100nm or less, whereby excellent optical characteristics can be exhibited.

Note that the composite tungsten oxide fine particles are single crystals, and can be confirmed by: in an electron microscopic image of a transmission electron microscope or the like, only uniform lattice grains are observed in each fine particle, and no grain boundary is observed. In the case where the volume ratio of the amorphous phase in the composite tungsten oxide fine particles is 50% or less, it can be confirmed that uniform lattice grains are observed in the entire particles and almost no lattice-indistinct points are observed in the transmission electron microscope image as well.

Further, since the amorphous phase is present in many cases in the outer peripheral portion of each fine particle, the volume ratio of the amorphous phase can be calculated in many cases by focusing attention on the outer peripheral portion of each fine particle. For example, when an amorphous phase in which lattice grains are not conspicuous is present in a layered manner in the outer periphery of the spherical composite tungsten oxide fine particles, the volume ratio of the amorphous phase in the composite tungsten oxide fine particles is 50% or less when the thickness is 10% or less of the average particle diameter.

On the other hand, when the composite tungsten oxide fine particles are dispersed in a matrix of a solid medium such as a resin constituting a composite tungsten oxide fine particle dispersion, if the difference obtained by subtracting the crystallite diameter from the average particle diameter of the dispersed composite tungsten oxide fine particles is 20% or less of the average particle diameter, the composite tungsten oxide fine particles belong to a single crystal having an amorphous phase volume ratio of 50% or less.

From the above, it is preferable to appropriately adjust the synthesis step, the pulverization step, and the dispersion step of the composite tungsten oxide fine particles in accordance with the production equipment so that the difference obtained by subtracting the crystallite diameter from the average particle diameter of the composite tungsten oxide fine particles dispersed in the composite tungsten oxide fine particle dispersion becomes 20% or less of the value of the average particle diameter.

The crystal structure or lattice constant of the composite tungsten oxide fine particles was measured by determining the crystal structure contained in the fine particles of the composite tungsten oxide obtained by removing the solvent of the dispersion for forming a near-infrared absorber by X-ray diffraction, and calculating the a-axis length and the c-axis length as the lattice constants by using the Rietveld method.

(2) Particle size and crystallite diameter

The composite tungsten oxide fine particles of the present invention have an average particle diameter of 100nm or less. From the viewpoint of more excellent near-infrared absorption characteristics, the average particle diameter is preferably 10nm or more and 100nm or less, more preferably 10nm or more and 80nm or less, and still more preferably 10nm or more and 60nm or less. The most excellent near infrared absorption characteristics are exhibited when the average particle diameter is in the range of 10nm to 60 nm.

Here, the average particle diameter refers to a value of a diameter of each of the unagglomerated composite tungsten oxide fine particles, and is an average particle diameter of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion liquid described below.

On the other hand, the average particle diameter does not include the diameter of the aggregate of the composite tungsten oxide fine particles, and is different from the dispersed particle diameter.

The average particle diameter is calculated from an electron microscopic image of the composite tungsten oxide fine particles.

The average particle diameter of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion is determined as follows: from the transmission electron microscope image of the flaked sample of the composite tungsten oxide fine particle dispersion liquid taken out by the cross-sectional processing, the particle diameters of 100 composite tungsten oxide fine particles were measured by using an image processing apparatus, and the average value thereof was calculated. For the Cross-sectional processing for taking out the thin slice sample, a microtome, a Cross-section polisher (Cross-section polisher), a Focused Ion Beam (FIB) apparatus, or the like can be used. The average particle diameter of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion is an average value of the particle diameters of the composite tungsten oxide fine particles dispersed in the matrix solid medium.

From the viewpoint of exhibiting excellent infrared absorption characteristics, the crystallite diameter of the composite tungsten oxide fine particles is preferably 10nm or more and 100nm or less, more preferably 10nm or more and 80nm or less, and still more preferably 10nm or more and 60nm or less. When the crystallite diameter is within the range of 10nm to 60nm, the most excellent near-infrared absorption characteristics can be exhibited.

The lattice constant or crystallite diameter of the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion obtained after the crushing treatment, pulverization treatment, or dispersion treatment described below is maintained in the composite tungsten oxide fine particles obtained by removing volatile components from the composite tungsten oxide fine particle dispersion, or in the composite tungsten oxide fine particles contained in the composite tungsten oxide fine particle dispersion obtained from the composite tungsten oxide fine particle dispersion.

As a result, the effects of the present invention can be exhibited also in the composite tungsten oxide fine particle dispersion liquid of the present invention or the composite tungsten oxide fine particle dispersion liquid containing the composite tungsten oxide fine particles.

(3) Composition of composite tungsten oxide fine particles

The composite tungsten oxide fine particles of the present invention are preferably composite tungsten oxide fine particles represented by the general formula MxWyOz (wherein M is at least 1 element selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb, W is tungsten, O is oxygen, and x/y is 0.001. ltoreq. x/y.ltoreq.1, z/y is 2.0. ltoreq. z/y.ltoreq.3.0).

The composite tungsten oxide fine particles represented by the general formula MxWyOz will be described.

M element, x, y, z and crystal structure thereof in the general formula MxWyOz have close relation with free electron density of the composite tungsten oxide particles, and great influence is caused on near infrared ray absorption characteristics.

Generally speaking, tungsten trioxide (WO)₃) Due to deficiency of middle energizerThere are effective free electrons, and thus the near infrared ray absorption characteristics are low.

The inventors of the present invention have found that a composite tungsten oxide is produced by adding an M element (wherein the M element is at least one element selected from the group consisting of H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, and Yb) to the tungsten oxide, thereby generating free electrons in the composite tungsten oxide, exhibiting absorption characteristics from the free electrons in the near infrared region, this is effective as a near-infrared ray absorbing material having a wavelength of about 1000nm, and the composite tungsten oxide is chemically stable, and is effective as a near-infrared ray absorbing material having excellent weather resistance. The M element is preferably Cs, Rb, K, Tl, Ba, or In, and when the M element is Cs or Rb, the composite tungsten oxide is easily formed into a hexagonal crystal structure. As a result, the visible light is transmitted, and the near infrared ray is absorbed and converted into heat, which is particularly preferable for the following reason. When two or more kinds of elements are selected as the M element, one of the elements is selected from Cs, Rb, K, Tl, Ba, and In, and the remaining elements are selected from 1 or more kinds of elements constituting the M element, hexagonal crystals may be formed.

The inventors of the present invention will now explain the finding of the value of x indicating the amount of the element M added.

When the x/y value is 0.001 or more, a sufficient amount of free electrons can be generated to obtain the desired near infrared absorption characteristics. Further, as the amount of the element M added increases, the amount of free electrons supplied increases, and the near infrared absorption characteristics also improve, but the effect is saturated when the x/y value is about 1. Further, when the value of x/y is 1 or less, it is preferable to avoid formation of an impurity phase in the composite tungsten oxide fine particles.

Next, the findings of the present inventors on the z value indicating the oxygen amount control are explained.

In the fine particles of the composite tungsten oxide represented by the general formula MxWyOz, the z/y value is preferably 2.0. ltoreq. x/y. ltoreq.3.0, more preferably 2.2. ltoreq. z/y3.0 or less, more preferably 2.6 or less, and still more preferably 2.7 or less, z/y or less 3.0 or less. This is because, if the z/y value is 2.0 or more, the occurrence of WO which is not the target in the composite tungsten oxide can be avoided₂And chemical stability as a material can be obtained, and thus can be applied as an effective infrared absorbing material. On the other hand, when the z/y value is 3.0 or less, a desired amount of free electrons are generated in the tungsten oxide, and thus the infrared absorbing material is highly efficient.

(4) Surface coating film of composite tungsten oxide fine particles

In order to improve the weather resistance of the composite tungsten oxide fine particles, at least a part of the surface of the composite tungsten oxide fine particles is preferably coated with a surface coating film containing 1 or more elements selected from silicon, zirconium, titanium, and aluminum. These surface coating films are substantially transparent and do not suffer from a decrease in visible light transmittance due to the addition. The coating method is not particularly limited, and the surface of the composite tungsten oxide fine particles can be coated by adding an alkoxide of a metal containing the element to a solution in which the composite tungsten oxide fine particles are dispersed. In this case, the surface coating film contains oxygen atoms, but more preferably the surface coating film is composed of an oxide.

(5) Summary of the invention

The lattice constant, average particle diameter, and crystallite diameter of the composite tungsten oxide fine particles described in detail above can be controlled by a predetermined synthesis condition. Specifically, in the thermal plasma method, the solid-phase reaction method, or the like described below, the temperature (firing temperature) at which the fine particles are produced, the production time (firing time), the production environment (firing environment), the form of the precursor material, the annealing treatment after production, the doping of the impurity element, or other synthesis conditions can be appropriately set and controlled. On the other hand, the content of volatile components in the composite tungsten oxide fine particles can be controlled by appropriately setting the storage method or storage environment of the fine particles, the temperature when drying the fine particle dispersion, the drying time, the drying method, and other production conditions. The content of volatile components in the composite tungsten oxide fine particles does not depend on the crystal structure of the composite tungsten oxide fine particles, or the synthesis method such as the thermal plasma method or the solid-phase reaction described below.

[b] Method for synthesizing composite tungsten oxide particles

The method for synthesizing the composite tungsten oxide fine particles of the present invention will be described.

Examples of the method for synthesizing the composite tungsten oxide fine particles of the present invention include a thermal plasma method in which a starting material of a tungsten compound is put into a thermal plasma; or a solid-phase reaction method in which a tungsten compound starting material is heat-treated in a reducing gas atmosphere. The composite tungsten oxide fine particles synthesized by the thermal plasma method or the solid-phase reaction method are subjected to dispersion treatment or pulverization and dispersion treatment.

The following describes the composite tungsten oxide fine particles synthesized by (1) the thermal plasma method, (2) the solid-phase reaction method, and (3) in this order.

(1) Thermal plasma method

The thermal plasma method is described in order of (i) raw materials used in the thermal plasma method, (ii) the thermal plasma method and conditions thereof.

(i) Raw material for thermal plasma method

In the synthesis of the composite tungsten oxide fine particles of the present invention by the thermal plasma method, a mixed powder of a tungsten compound and an M element compound can be used as a raw material.

The tungsten compound is preferably 1 or more selected from the following: tungstic acid (H)₂WO₄) Ammonium tungstate, tungsten hexachloride, and tungsten hydrate obtained by adding water to tungsten hexachloride dissolved in alcohol, hydrolyzing the mixture, and then evaporating the solvent.

In addition, as the M element compound, preferably used is selected from the M element oxide, hydroxide, nitrate, sulfate, chloride, carbonate of more than 1.

Wet-mixing an aqueous solution containing the tungsten compound and the M element compound so that the ratio of M element to W element is MxWyOz (wherein M is the M element, W is tungsten, O is oxygen, x/y is 0.001-1, and z/y is 2.0-3.0). Then, the obtained mixed solution is dried to obtain mixed powder of the M element compound and the tungsten compound. The mixed powder can be used as a raw material for a thermal plasma method.

In addition, the mixed powder is subjected to the firing in the stage 1 under an atmosphere of an inert gas alone or an atmosphere of a mixed gas of an inert gas and a reducing gas to obtain a composite tungsten oxide, which can be used as a raw material for a thermal plasma method. In addition, the composite tungsten oxide obtained by firing in stage 1 in a mixed gas atmosphere of an inert gas and a reducing gas, and firing the fired product in stage 1 in stage 2 in an inert gas atmosphere can be used as a raw material for the thermal plasma method.

(ii) Thermal plasma method and conditions therefor

As the thermal plasma used in the present invention, for example, any of a direct current arc plasma, a high frequency plasma, a microwave plasma, and a low frequency alternating current plasma can be applied, or a plasma generated by an electrical method in which these plasmas are superimposed, or a magnetic field is applied to a direct current plasma, a plasma generated by irradiation of a high output laser, and a plasma generated by a high output electron beam or an ion beam can be applied. Among them, regardless of the thermal plasma used, thermal plasma having a high temperature portion of 10000 to 15000K is preferable, and particularly plasma capable of controlling the generation time of fine particles is preferable.

The raw material supplied to the thermal plasma having the high-temperature portion is instantaneously evaporated in the high-temperature portion. Then, the evaporated raw material is condensed in the process of reaching the plasma tail flame portion, and rapidly solidified outside the plasma flame, thereby producing composite tungsten oxide fine particles.

The synthesis method will be described with reference to FIG. 1, taking as an example the case of using a high-frequency plasma reaction apparatus.

First, the inside of a reaction system comprising a water-cooled quartz double tube and the inside of the reaction vessel 6 was evacuated to about 0.1Pa (about 0.001Torr) by a vacuum evacuation apparatus. After the reaction system was evacuated, the inside of the reaction system was filled with argon gas to prepare an argon gas flow system having 1 atmosphere.

Then, a gas selected from the group consisting of argon, a mixed gas of argon and helium (Ar-He mixed gas), and a mixed gas of argon and nitrogen (Ar-N mixed gas) is introduced into the reaction vessel through the plasma gas supply nozzle 4 at a flow rate of 30 to 45L/min₂Mixed gas) as a plasma gas. On the other hand, an Ar-He mixed gas is introduced from a sheath gas supply nozzle 3 at a flow rate of 60 to 70L/min as a sheath gas flowing adjacent to and outside the plasma region.

Then, an alternating current is applied to the high-frequency coil 2, and thermal plasma 1 is generated by a high-frequency electromagnetic field (frequency 4 MHz). In this case, the high-frequency power is set to 30 to 40 kW.

Then, the mixed powder of the M element compound and the tungsten compound or the composite tungsten oxide obtained by the above synthesis method is introduced into the thermal plasma through the powder supply nozzle 5 at a ratio of a supply speed of 25 to 50g/min using argon gas of 6 to 98L/min supplied from the gas supply device as a carrier gas, and reacted for a predetermined time. After the reaction, the produced composite tungsten oxide fine particles are collected because they are deposited on the filter 8 through the suction tube 7.

The carrier gas flow rate and the raw material supply rate greatly affect the generation time of the fine particles. Therefore, it is preferable that the carrier gas flow rate is set to 6L/min to 9L/min, and the raw material supply rate is set to 25 to 50 g/min.

Preferably, the plasma gas flow rate is set to 30L/min to 45L/min, and the sheath flow rate is set to 60L/min to 70L/min. The plasma gas has the following functions: the thermal plasma region having a high temperature portion of 10000-15000K is maintained, and the sheath flow gas cools the inner wall surface of the quartz torch in the reaction vessel, thereby preventing the melting of the quartz torch. At the same time, since the plasma gas and the sheath gas affect the shape of the plasma region, the gas flow rates thereof become important parameters for controlling the shape of the plasma region. As the flow rates of the plasma gas and the sheath gas are increased, the shape of the plasma region is extended in the gas flow direction, and the temperature gradient of the plasma tail flame portion is made gentler.

When the crystallite diameter of the composite tungsten oxide obtainable by the thermal plasma method exceeds 200nm, or when the dispersion particle diameter of the composite tungsten oxide in the composite tungsten oxide fine particle dispersion liquid obtainable by the composite tungsten oxide obtainable by the thermal plasma method exceeds 200nm, the following pulverization and dispersion treatment can be performed. When the composite tungsten oxide is synthesized by the thermal plasma method, the plasma conditions or the conditions for subsequent pulverization and dispersion treatment are appropriately selected, and pulverization conditions (pulverization conditions) that can impart the average particle diameter, crystallite diameter, and lattice constant to the composite tungsten oxide are determined.

(2) Solid phase reaction method

In the solid-phase reaction method, (i) raw materials used in the solid-phase reaction method, (ii) firing and conditions thereof in the solid-phase reaction method are described in order.

(i) Raw materials for solid phase reaction

In the synthesis of the composite tungsten oxide fine particles of the present invention by the solid-phase reaction method, a tungsten compound and an M element compound are used as raw materials.

The tungsten compound is preferably selected from tungstic acid (H)₂WO₄) Ammonium tungstate, tungsten hexachloride, and 1 or more of tungsten hydrates obtained by adding water to tungsten hexachloride dissolved in alcohol, hydrolyzing the mixture, and then evaporating the solvent.

In addition, the M element compound used for producing the raw material of the composite tungsten oxide fine particles represented by the general formula MxWyOz (wherein M is 1 or more elements selected from Cs, Rb, K, Tl, Ba and In, x/y is 0.001. ltoreq. x/y. ltoreq.1, and z/y is 2.0. ltoreq. z/y. ltoreq.3.0) of the embodiment is preferably 1 or more elements selected from oxides, hydroxides, nitrates, sulfates, chlorides and carbonates of M elements.

Further, a compound containing 1 or more impurity elements selected from Si, Al, and Zr (which may be referred to as "impurity element compound" in the present invention) may be contained as a raw material. The impurity element compound does not react with the composite tungsten compound in the subsequent firing step, and has an effect of suppressing crystal growth of the composite tungsten oxide and preventing coarsening of the crystal. The impurity element-containing compound is preferably at least 1 selected from the group consisting of oxides, hydroxides, nitrates, sulfates, chlorides, and carbonates, and particularly preferably colloidal silica or colloidal alumina having a particle size of 500nm or less.

Wet-mixing an aqueous solution containing the tungsten compound and the M element compound so that the ratio of M element to W element is MxWyOz (wherein M is the M element, W is tungsten, O is oxygen, x/y is 0.001-1.0, and z/y is 2.0-3.0). When the impurity element compound is contained as a raw material, wet mixing is performed so that the impurity element compound is 0.5 mass% or less. Then, the obtained mixed solution is dried to obtain a mixed powder of the M element compound and the tungsten compound or a mixed powder of the M element compound containing the impurity element compound and the tungsten compound.

(ii) Calcination by solid-phase reaction and conditions therefor

The mixed powder of the M element compound and the tungsten compound obtained by the wet mixing or the mixed powder of the M element compound containing the impurity element compound and the tungsten compound is fired in 1 stage in an atmosphere of an inert gas alone or an atmosphere of a mixed gas of an inert gas and a reducing gas. The firing temperature is preferably close to the temperature at which the composite tungsten oxide fine particles start to crystallize, and specifically, the firing temperature is preferably 1000 ℃ or lower, more preferably 800 ℃ or lower, and still more preferably in a temperature range of 800 ℃ or lower and 500 ℃ or higher.

The reducing gas is not particularly limited, and is preferably H₂. In addition, in the use of H₂In the case of the reducing gas, the concentration thereof may be appropriately selected depending on the firing temperature and the amount of the starting material, and is not particularly limited. For example, 20 vol% or less, preferably 10 vol% or less, and more preferably 7 vol% or less. When the concentration of the reducing gas is 20% by volume or less, the formation of WO having no solar radiation absorbing function due to rapid reduction can be avoided₂. In this case, the composite tungsten of the present invention can be formed by controlling the firing conditionsThe average particle diameter, crystallite diameter, and a-axis length or c-axis length of the lattice constant of the oxide fine particles are controlled to be specified values.

Of course, in the synthesis of the composite tungsten oxide fine particles, tungsten trioxide may be used instead of the tungsten compound.

(3) Synthetic composite tungsten oxide fine particles

When the composite tungsten oxide fine particles obtained by a synthesis method based on a thermal plasma method or a solid-phase reaction method are used to produce a composite tungsten oxide fine particle dispersion liquid described below, if the dispersion particle size of the fine particles contained in the dispersion liquid exceeds 200nm, the composite tungsten oxide fine particle dispersion liquid may be pulverized and dispersed in the following step of producing the composite tungsten oxide fine particle dispersion liquid. Then, as long as the values of the average particle diameter, crystallite diameter, and a-axis length or c-axis length of the lattice constant of the composite tungsten oxide fine particles obtained by pulverization and dispersion treatment fall within the ranges of the present invention, the composite tungsten oxide fine particles of the present invention or the composite tungsten oxide fine particle dispersion liquid obtained from the dispersion liquid thereof can realize excellent near-infrared absorption characteristics.

As described above, the composite tungsten oxide fine particles of the present invention have an average particle diameter of 100nm or less.

Here, when the average particle diameter of the composite tungsten oxide fine particles obtained by the method described in "[ b ] a method for synthesizing composite tungsten oxide fine particles" exceeds 100nm, the composite tungsten oxide fine particles of the present invention can be produced by the following steps: a step (pulverization/dispersion treatment step) of pulverizing and dispersing the particles to produce a composite tungsten oxide fine particle dispersion; the produced composite tungsten oxide fine particle dispersion liquid is subjected to a drying treatment to remove volatile components (almost solvent).

The following describes (i) the pulverization and dispersion treatment step and (ii) the drying step in this order.

(i) Pulverizing and dispersing treatment process

The process for pulverizing and dispersing the composite tungsten oxide fine particles comprises the following steps: the composite tungsten oxide fine particles are uniformly dispersed in a monomer of a thermosetting resin in an appropriate uncured state or in an appropriate solvent described below together with a dispersant described below, and are not aggregated.

The grinding and dispersing step ensures that the average particle diameter of the composite tungsten oxide fine particles is 100nm or less, preferably 10nm or more and 100nm or less, and the lattice constant of the crystal is ensured to be in the a-axis

Above and

in the following, the c-axis is

Above and

hereinafter, [ c-axis lattice constant/a-axis lattice constant ] is more preferable]The value of (b) is in the range of 1.0221 or more and 1.0289 or less.

Specifically, for example, a method of pulverizing and dispersing for a predetermined time using an apparatus such as a bead mill, a ball mill, a sand mill, a paint dispersing machine, or an ultrasonic homogenizer can be exemplified. Among them, it is preferable to pulverize and disperse the particles by a media agitation mill such as a bead mill, a ball mill, a sand mill, and a paint disperser using media such as beads, balls, and ottawa sand, because it takes a short time to obtain a desired average particle size or dispersed particle size.

The composite tungsten oxide fine particles can be dispersed into the dispersion liquid by the pulverization and dispersion treatment using the media mill, and the composite tungsten oxide fine particles can be further pulverized and dispersed (that is, the pulverization and dispersion treatment) by the collision of the composite tungsten oxide fine particles with each other or the collision of the medium media with the fine particles.

By the mechanical dispersion treatment process using these devices, the composite tungsten oxide fine particles are dispersed in the solvent, and at the same time, the composite tungsten oxide fine particles are made fine by collision or the like between the composite tungsten oxide fine particles, and strain or deformation is imparted to the hexagonal crystal structure contained in the composite tungsten oxide fine particles, so that the superposed state of the electron orbitals of the atoms constituting the crystal structure is changed, and the amount of free electrons is increased.

The micronization of the composite tungsten oxide fine particles and the variation of the a-axis length or the c-axis length, which is a lattice constant in the hexagonal crystal structure, differ depending on the device constant of the pulverizing device. And, what is important is: the pulverizing apparatus may be one which performs experimental pulverization in advance and gives the composite tungsten oxide fine particles the predetermined average particle diameter, crystallite diameter, and a-axis length or c-axis length of lattice constant, and the pulverizing conditions may be determined in advance.

The state of the composite tungsten oxide fine particle dispersion can be confirmed by measuring the dispersion state of the composite tungsten oxide fine particles when the composite tungsten oxide fine particles are dispersed in a solvent. For example, a sample is collected from a liquid in which the composite tungsten oxide fine particles of the present invention are present in a solvent in a state of fine particles and fine particles being aggregated, and the sample can be confirmed by measurement with various commercially available particle size distribution meters. As the particle size distribution meter, a known measurement apparatus such as ELS-8000 manufactured by Otsuka electronics Co., Ltd can be used, for example, based on the dynamic light scattering method.

The composite tungsten oxide fine particles of the present invention preferably have a dispersion particle diameter of 200nm or less, and more preferably have a dispersion particle diameter of 10nm or more and 200nm or less.

The near-infrared ray absorbing component containing the composite tungsten oxide fine particles of the present invention absorbs light in the near-infrared region, particularly, in the vicinity of a wavelength of 900 to 2200nm, to a large extent, and therefore the transmitted color tone of visible light may be blue or green. On the other hand, when the composite tungsten oxide fine particles contained in the near-infrared ray absorption layer have a dispersion particle diameter of 1to 200nm, light scattering in the visible light region having a wavelength of 380 to 780nm due to geometric scattering or mie scattering is not caused, and therefore color development of the near-infrared ray absorption layer due to light scattering is reduced, and the visible light transmittance is increased. In the rayleigh scattering region, since scattered light decreases in proportion to the particle diameter to the power of 6, scattering decreases as the dispersed particle diameter decreases, and transparency improves. Therefore, when the dispersed particle diameter is 200nm or less, scattered light becomes extremely small, and transparency is further increased, which is preferable.

As described above, when the dispersed particle diameter of the fine particles is less than 200nm, transparency can be secured, and thus the near-infrared ray curable ink composition is easily colored. When importance is attached to the transparency, the dispersion particle diameter is 150nm or less, and more preferably 100nm or less. On the other hand, if the dispersed particle size is 10nm or more, the industrial production is easy.

Here, the particle diameter of the composite tungsten oxide fine particles dispersed in the composite tungsten oxide fine particle dispersion will be briefly described. The dispersion particle diameter of the composite tungsten oxide fine particles means the particle diameter of the monomer particles of the composite tungsten oxide fine particles dispersed in the solvent or the particle (agglomerate particle) obtained by agglomerating the composite tungsten oxide fine particles, and can be measured by various commercially available particle size distribution meters. For example, a sample of the composite tungsten oxide fine particle dispersion may be collected and measured using ELS-8000 manufactured by Otsuka Denshi, which is a principle of the dynamic light scattering method.

The composite tungsten oxide fine particle dispersion having a content of the composite tungsten oxide fine particles obtained by the above synthesis method of 0.01 mass% to 80 mass% is excellent in solution stability. When an appropriate liquid medium, dispersant, coupling agent or surfactant is selected, gelation of the dispersion or sedimentation of particles does not occur even after 6 months or more when the dispersion is left in a thermostatic bath at a temperature of 40 ℃, and the dispersed particle diameter can be maintained in the range of 10 to 200 nm.

The dispersion particle size of the composite tungsten oxide fine particle dispersion may be different from the average particle size of the composite tungsten oxide fine particles dispersed in the composite tungsten oxide fine particle dispersion. This is because, even if the fine composite tungsten oxide particles are aggregated in the fine composite tungsten oxide particle dispersion, the aggregation of the fine composite tungsten oxide particles is decomposed when the fine composite tungsten oxide particle dispersion is processed into a fine composite tungsten oxide particle dispersion.

(ii) Drying step

The drying step is a step of drying the composite tungsten oxide fine particle dispersion obtained in the pulverizing and dispersing step to remove volatile components in the dispersion, thereby obtaining the composite tungsten oxide fine particles of the present invention.

The drying apparatus is preferably an air dryer, a universal mixer, a belt mixer, a vacuum fluidized dryer, a vibration fluidized dryer, a freeze dryer, a RIBOCONE, a rotary kiln, a spray dryer, a pulverizing dryer, or the like, from the viewpoint of allowing heating and/or pressure reduction, and facilitating mixing or recovery of the fine particles, but is not limited thereto.

[c] Uncured thermosetting resin

The uncured thermosetting resin of the present invention is a thermosetting resin comprising: the near-infrared-curable ink composition is in the form of an uncured liquid at the time, but is cured by applying thermal energy from the composite tungsten oxide fine particles after being irradiated with near-infrared rays.

Specific examples of the uncured thermosetting resin include uncured resins such as epoxy resins, polyurethane resins, acrylic resins, urea resins, melamine resins, phenol resins, ester resins, polyimide resins, silicone resins, and unsaturated polyester resins.

The uncured thermosetting resin may contain a monomer or oligomer that forms a thermosetting resin by a curing reaction, and a known curing agent that is added as appropriate. And a known curing accelerator may be added to the curing agent.

[d] Other ingredients

The near-infrared curable ink composition of the present invention further contains other components such as a pigment, a solvent, and a dispersant as necessary.

Therefore, (1) the pigment and the dye, (2) the dispersant, and (3) the solvent will be described in this order.

(1) Pigments and dyes

As the pigment that can be used for coloring the near-infrared curable ink composition of the present invention, a known pigment can be used without particular limitation. Specifically, organic pigments such as insoluble pigments and lake pigments, and inorganic pigments such as carbon black are preferably used.

These pigments are preferably present in a state of being dispersed in the near-infrared ray curable ink composition of the present invention. The method for dispersing these pigments is not particularly limited, and known methods can be used.

As described above, the insoluble pigment is not particularly limited, and examples thereof include azo, methine dye, diphenylmethane, triphenylmethane, quinacridone, anthraquinone, perylene, indigo, quinophthalone, isoindolinone, isoindoline, azine, perylene, quinophthalone, isoindolinone, indoline, perylene, quinophthalone, perylene,

Oxazine, thiazine, II

Oxazines, thiazoles, phthalocyanines, pyrrolopyrrolediones and the like are preferred insoluble pigments.

Here, the names of commercially available pigments which can be preferably used are listed below.

Examples of the pigment for magenta or red include c.i. pigment red2, c.i. pigment red 3, c.i. pigment red 5, c.i. pigment red 6, c.i. pigment red 7, c.i. pigment red 15, c.i. pigment red 16, c.i. pigment red 48:1, c.i. pigment red 53:1, c.i. pigment red 57:1, c.i. pigment red 122, c.i. pigment red 123, c.i. pigment red 139, c.i. pigment red 144, c.i. pigment red 149, c.i. pigment red 166, c.i. pigment red 177, c.i. pigment red 178, c.i. pigment red 202, c.i. pigment red 222, c.i. pigment violet 19, and the like.

Examples of orange or yellow pigments include c.i. pigment orange 31, c.i. pigment orange 43, c.i. pigment yellow 12, c.i. pigment yellow 13, c.i. pigment yellow 14, c.i. pigment yellow 15:3, c.i. pigment yellow 17, c.i. pigment yellow 74, c.i. pigment yellow 93, c.i. pigment yellow 128, c.i. pigment yellow 94, and c.i. pigment yellow 138.

Examples of the pigment for green or bluish color include c.i. pigment blue 15, c.i. pigment blue 15:2, c.i. pigment blue 15:3, c.i. pigment blue 16, c.i. pigment blue 60, and c.i. pigment green 7.

Examples of the black pigment include c.i. pigment black 1, c.i. pigment black 6, and c.i. pigment black 7.

As described above, the inorganic pigment is not particularly limited, and an extender pigment containing carbon black, titanium dioxide, zinc sulfide, zinc oxide, zinc phosphate, mixed metal oxide phosphate, iron oxide, manganese iron oxide, chromium oxide, ultramarine, nickel or chromium antimony titanium oxide, cobalt oxide, aluminum oxide, silicon oxide, silicate, zirconium oxide, a mixed oxide of cobalt and aluminum, molybdenum sulfide, a rutile mixed phase pigment, a rare earth sulfide, bismuth vanadate, aluminum hydroxide, or barium sulfate is preferable.

The dispersed pigment contained in the near-infrared curable ink composition of the present invention preferably has a dispersed particle diameter of 10nm to 200 nm. This is because the storage stability in the near-infrared curable ink composition is good when the dispersion particle diameter of the pigment dispersion is 10nm or more and 200nm or less.

The dye used in the present invention is not particularly limited, and any oil-soluble dye or water-soluble dye can be used, and a yellow dye, a magenta dye, a cyan dye, and the like can be preferably used.

As the yellow dye, there can be exemplified an aryl dye or a heteroaryl azo dye having, as a coupling component, a phenol, a naphthol, an aniline, a pyrazolone, a pyridone, an open-chain active methylene compound;

such as methine azo dyes having an open-chain type active methylene compound as a coupling component;

methine dyes such as benzylidene dyes or monomethyl Oxonol (Oxonol) dyes;

quinone dyes such as naphthoquinone dyes and anthraquinone dyes, and the like. Examples of the other dye types include quinophthalone dyes, nitro-nitroso dyes, acridine dyes, and acridone dyes.

Some of the chromophores of these dyes can dissociate to initially appear yellow. The cation may be an inorganic cation such as an alkali metal or ammonium, or may be pyridine

The organic cation such as quaternary ammonium salt may be a polymer cation having these in a partial structure.

As the magenta dye, there can be exemplified an aryl or heteroaryl azo dye having a phenol type, a naphthol type, an aniline type as a coupling component;

such as methine azo dyes having pyrazolones, pyrazolotriazoles as coupling components;

methine dyes such as arylene dyes, styryl dyes, merocyanine dyes, Oxonol (Oxonol) dyes, and the like;

carbons such as diphenylmethane dye, triphenylmethane dye, xanthene dye, etc

An ionic dye;

quinone dyes such as naphthoquinone, anthraquinone, anthrapyridone, and the like;

for example two

And condensed polycyclic dyes such as oxazine dyes.

These dyes may initially appear magenta upon dissociation of a portion of the chromophore. The counter cation in this case may be an inorganic cation such as an alkali metal or ammonium. In addition, the cation may be an organic cation such as pyridinium or quaternary ammonium salt. And may be a polymer cation having these in a partial structure.

As the cyan dye, methine azo dyes such as indoaniline dyes, indophenol dyes, and the like;

polymethine dyes such as cyanine dyes, Oxonol (Oxonol) dyes, merocyanine dyes, and the like;

carbons such as diphenylmethane dye, triphenylmethane dye, xanthene dye, etc

An ionic dye;

a phthalocyanine dye; anthraquinone dyes; for example aryl or heteroaryl azo dyes having phenols, naphthols, anilines as coupling components; indigo-thioindigo dyes.

Some of the chromophores of these dyes dissociate to initially appear cyan. The counter cation in this case may be an inorganic cation such as an alkali metal or ammonium, or may be pyridine

Quaternary ammonium salts and the like. And may also be a polymer cation having these in a partial structure. In addition, a black dye such as a polyazo dye may be used.

The water-soluble dye used in the present invention is not particularly limited, and a direct dye, an acid dye, an edible dye, a basic dye, a reactive dye, or the like can be preferably used.

As the water-soluble dye, specific dye names that can be preferably used are listed below.

Examples of the direct red include c.i. direct red2, c.i. direct red 4, c.i. direct red 9, c.i. direct red 23, c.i. direct red 26, c.i. direct red 31, c.i. direct red 39, c.i. direct red 62, c.i. direct red 63, c.i. direct red 72, c.i. direct red 75, c.i. direct red 76, c.i. direct red 79, c.i. direct red 80, c.i. direct red 81, c.i. direct red 83, c.i. direct red 84, c.i. direct red 89, c.i. direct red 92, c.i. direct red 95, c.i. direct red 111, c.i. direct red 173, c.i. direct red 184, c.i. direct red 207, c.i. direct red 211, c.i. direct red 212, c.i. direct red 232, c.i. direct red 223, c.i. direct red 225, c.i. direct red 223, c.i. direct red 225, c.i. direct red 223, c.,

c.i. direct violet 7, c.i. direct violet 9, c.i. direct violet 47, c.i. direct violet 48, c.i. direct violet 51, c.i. direct violet 66, c.i. direct violet 90, c.i. direct violet 93, c.i. direct violet 94, c.i. direct violet 95, c.i. direct violet 98, c.i. direct violet 100, c.i. direct violet 101,

c.i. direct yellow 8, c.i. direct yellow 9, c.i. direct yellow 11, c.i. direct yellow 12, c.i. direct yellow 27, c.i. direct yellow 28, c.i. direct yellow 29, c.i. direct yellow 33, c.i. direct yellow 35, c.i. direct yellow 39, c.i. direct yellow 41, c.i. direct yellow 44, c.i. direct yellow 50, c.i. direct yellow 53, c.i. direct yellow 58, c.i. direct yellow 59, c.i. direct yellow 68, c.i. direct yellow 86, c.i. direct yellow 87, c.i. direct yellow 93, c.i. direct yellow 95, c.i. direct yellow 96, c.i. direct yellow 98, c.i. direct yellow 100, c.i. direct yellow 106, c.i. direct yellow 108, c.i. direct yellow 109, c.i. direct yellow 110, c.i. direct yellow 163, c.i. direct yellow 144, c.i. direct yellow 142, c.i. direct yellow 144,

c.i. direct blue 1, c.i. direct blue 10, c.i. direct blue 15, c.i. direct blue 22, c.i. direct blue 25, c.i. direct blue 55, c.i. direct blue 67, c.i. direct blue 68, c.i. direct blue 71, c.i. direct blue 76, c.i. direct blue 77, c.i. direct blue 78, c.i. direct blue 80, c.i. direct blue 84, c.i. direct blue 86, c.i. direct blue 87, c.i. direct blue 90, c.i. direct blue 98, c.i. direct blue 106, c.i. direct blue 108, c.i. direct blue 109, c.i. direct blue 151, c.i. direct blue 156, c.i. direct blue 158, c.i. direct blue 159, c.i. direct blue 160, c.i. direct blue 168, c.i. direct blue 193, c.i. direct blue 192, c.i. direct blue 211, c.i. direct blue 207, c.i. direct blue 213, c.i. direct blue 207, c.i. direct blue 218, c.i. direct blue 207, c.i. direct blue 125, c.i. direct blue 207, c.i, C.i. direct blue 236, c.i. direct blue 237, c.i. direct blue 244, c.i. direct blue 248, c.i. direct blue 249, c.i. direct blue 251, c.i. direct blue 252, c.i. direct blue 264, c.i. direct blue 270, c.i. direct blue 280, c.i. direct blue 288, c.i. direct blue 289, c.i. direct blue 291,

c.i. direct black 9, c.i. direct black 17, c.i. direct black 19, c.i. direct black 22, c.i. direct black 32, c.i. direct black 51, c.i. direct black 56, c.i. direct black 62, c.i. direct black 69, c.i. direct black 77, c.i. direct black 80, c.i. direct black 91, c.i. direct black 94, c.i. direct black 97, c.i. direct black 108, c.i. direct black 112, c.i. direct black 113, c.i. direct black 114, c.i. direct black 117, c.i. direct black 118, c.i. direct black 121, c.i. direct black 122, c.i. direct black 125, c.i. direct black 132, c.i. direct black 146, c.i. direct black 154, c.i. direct black 166, c.i. direct black 168, c.i. direct black 199, c.i. direct black 173,

c.i. acid red 35, c.i. acid red 42, c.i. acid red 52, c.i. acid red 57, c.i. acid red 62, c.i. acid red 80, c.i. acid red 82, c.i. acid red 111, c.i. acid red 114, c.i. acid red 118, c.i. acid red 119, c.i. acid red 127, c.i. acid red 128, c.i. acid red 131, c.i. acid red 143, c.i. acid red 151, c.i. acid red 154, c.i. acid red 158, c.i. acid red 249, c.i. acid red 254, c.i. acid red 257, c.i. acid red 261, c.i. acid red 263, c.i. acid red 266, c.i. acid red 289, c.i. acid red 301, c.i. acid red 299, c.i. acid red 305, c.i. acid red 337, c.i. acid red 361, c.i. acid red 396,

C.I. acid Violet 5, C.I. acid Violet 34, C.I. acid Violet 43, C.I. acid Violet 47, C.I. acid Violet 48, C.I. acid Violet 90, C.I. acid Violet 103, C.I. acid Violet 126,

c.i. acid yellow 17, c.i. acid yellow 19, c.i. acid yellow 23, c.i. acid yellow 25, c.i. acid yellow 39, c.i. acid yellow 40, c.i. acid yellow 42, c.i. acid yellow 44, c.i. acid yellow 49, c.i. acid yellow 50, c.i. acid yellow 61, c.i. acid yellow 64, c.i. acid yellow 76, c.i. acid yellow 79, c.i. acid yellow 110, c.i. acid yellow 127, c.i. acid yellow 135, c.i. acid yellow 143, c.i. acid yellow 151, c.i. acid yellow 159, c.i. acid yellow 169, c.i. acid yellow 174, c.i. acid yellow 190, c.i. acid yellow 195, c.i. acid yellow 196, c.i. acid yellow 197, c.i. acid yellow 199, c.i. acid yellow 218, c.i. acid yellow 227,

c.i. acid blue 9, c.i. acid blue 25, c.i. acid blue 40, c.i. acid blue 41, c.i. acid blue 62, c.i. acid blue 72, c.i. acid blue 76, c.i. acid blue 78, c.i. acid blue 80, c.i. acid blue 82, c.i. acid blue 92, c.i. acid blue 106, c.i. acid blue 112, c.i. acid blue 113, c.i. acid blue 120, c.i. acid blue 127: 1. c.i. acid blue 129, c.i. acid blue 138, c.i. acid blue 143, c.i. acid blue 175, c.i. acid blue 181, c.i. acid blue 205, c.i. acid blue 207, c.i. acid blue 220, c.i. acid blue 221, c.i. acid blue 230, c.i. acid blue 232, c.i. acid blue 247, c.i. acid blue 258, c.i. acid blue 260, c.i. acid blue 264, c.i. acid blue 271, c.i. acid blue 277, c.i. acid blue 278, c.i. acid blue 279, c.i. acid blue 280, c.i. acid blue 288, c.i. acid blue 290, c.i. acid blue 326,

c.i. acid black 7, c.i. acid black 24, c.i. acid black 29, c.i. acid black 48, c.i. acid black 52: 1. c.i. acid black 172,

c.i. reactive red 3, c.i. reactive red 13, c.i. reactive red 17, c.i. reactive red 19, c.i. reactive red 21, c.i. reactive red 22, c.i. reactive red 23, c.i. reactive red24, c.i. reactive red 29, c.i. reactive red 35, c.i. reactive red 37, c.i. reactive red 40, c.i. reactive red 41, c.i. reactive red 43, c.i. reactive red 45, c.i. reactive red 49, c.i. reactive red 55,

c.i. reactive violet 1, c.i. reactive violet 3, c.i. reactive violet 4, c.i. reactive violet 5, c.i. reactive violet 6, c.i. reactive violet 7, c.i. reactive violet 8, c.i. reactive violet 9, c.i. reactive violet 16, c.i. reactive violet 17, c.i. reactive violet 22, c.i. reactive violet 23, c.i. reactive violet 24, c.i. reactive violet 26, c.i. reactive violet 27, c.i. reactive violet 33, c.i. reactive violet 34,

c.i. reactive yellow 2, c.i. reactive yellow 3, c.i. reactive yellow 13, c.i. reactive yellow 14, c.i. reactive yellow 15, c.i. reactive yellow 17, c.i. reactive yellow 18, c.i. reactive yellow 23, c.i. reactive yellow 24, c.i. reactive yellow 25, c.i. reactive yellow 26, c.i. reactive yellow 27, c.i. reactive yellow 29, c.i. reactive yellow 35, c.i. reactive yellow 37, c.i. reactive yellow 41, c.i. reactive yellow 42,

c.i. reactive blue 2, c.i. reactive blue 3, c.i. reactive blue 5, c.i. reactive blue 8, c.i. reactive blue 10, c.i. reactive blue 13, c.i. reactive blue 14, c.i. reactive blue 15, c.i. reactive blue 17, c.i. reactive blue 18, c.i. reactive blue 19, c.i. reactive blue 21, c.i. reactive blue 25, c.i. reactive blue 26, c.i. reactive blue 27, c.i. reactive blue 28, c.i. reactive blue 29, c.i. reactive blue 38,

c.i. reactive black 4, c.i. reactive black 5, c.i. reactive black 8, c.i. reactive black 14, c.i. reactive black 21, c.i. reactive black 23, c.i. reactive black 26, c.i. reactive black 31, c.i. reactive black 32, c.i. reactive black 34,

c.i. basic red 12, c.i. basic red 13, c.i. basic red 14, c.i. basic red 15, c.i. basic red 18, c.i. basic red 22, c.i. basic red 23, c.i. basic red24, c.i. basic red 25, c.i. basic red 27, c.i. basic red 29, c.i. basic red 35, c.i. basic red 36, c.i. basic red 38, c.i. basic red 39, c.i. basic red 45, c.i. basic red 46,

c.i. basic violet 1, c.i. basic violet 2, c.i. basic violet 3, c.i. basic violet 7, c.i. basic violet 10, c.i. basic violet 15, c.i. basic violet 16, c.i. basic violet 20, c.i. basic violet 21, c.i. basic violet 25, c.i. basic violet 27, c.i. basic violet 28, c.i. basic violet 35, c.i. basic violet 37, c.i. basic violet 39, c.i. basic violet 40, c.i. basic violet 48,

c.i. basic yellow 1, c.i. basic yellow 2, c.i. basic yellow 4, c.i. basic yellow 11, c.i. basic yellow 13, c.i. basic yellow 14, c.i. basic yellow 15, c.i. basic yellow 19, c.i. basic yellow 21, c.i. basic yellow 23, c.i. basic yellow 24, c.i. basic yellow 25, c.i. basic yellow 28, c.i. basic yellow 29, c.i. basic yellow 32, c.i. basic yellow 36, c.i. basic yellow 39, c.i. basic yellow 40,

c.i. basic blue 1, c.i. basic blue 3, c.i. basic blue 5, c.i. basic blue 7, c.i. basic blue 9, c.i. basic blue 22, c.i. basic blue 26, c.i. basic blue 41, c.i. basic blue 45, c.i. basic blue 46, c.i. basic blue 47, c.i. basic blue 54, c.i. basic blue 57, c.i. basic blue 60, c.i. basic blue 62, c.i. basic blue 65, c.i. basic blue 66, c.i. basic blue 69, c.i. basic blue 71,

c.i. basic black 8, etc.

The particle diameter of the pigment or the composite tungsten oxide fine particles of the coloring material contained in the near-infrared ray-curable ink described above is preferably determined in consideration of the characteristics of the applicator of the near-infrared ray-curable ink composition.

The near-infrared curable ink composition of the present invention includes a concept of a near-infrared curable ink composition containing no pigment or dye.

(2) Dispersing agent

The composite tungsten oxide fine particles of the present invention can be dispersed in a suitable monomer of a thermosetting resin in an uncured state or in a suitable solvent described below together with a suitable dispersant. By adding an appropriate dispersant, the composite tungsten oxide fine particles can be easily dispersed in the near-infrared ray curable ink, and it is expected that the curing variation of the coating film of the near-infrared ray curable ink can be suppressed.

As the dispersant, a commercially available dispersant can be suitably used, and preferably, the dispersant has a molecular structure having a main chain of polyester, polyacrylic acid, polyurethane, polyamine, polycaprolactone or polystyrene as a dispersant, and has an amino group, an epoxy group, a carboxyl group, a hydroxyl group, a sulfonic acid group, or the like as a functional group. The dispersant having such a molecular structure is less likely to change its quality when the near-infrared ray is intermittently irradiated to the coating film of the near-infrared ray curable ink of the present invention for several tens of seconds. Therefore, the deterioration, coloring, and other problems do not occur.

Examples of the above-mentioned dispersant include:

SOLSPERSE (registered trademark) (the same shall apply hereinafter) 3000, SOLSPERSE5000, SOLSPERSE9000, SOLSPERSE11200, SOLSPERSE12000, SOLSPERSE13000, SOLSPERSE13240, SOLSPERSE13650, SOLSPERSE13940, SOLSPERSE16000, SOLSPERSE17000, SOLSPERSE18000, SOLSPERSE20000, SOLSPERSE21000, SOLSPERSE240 24000SC, SOLSPERSE24000GR, SOLSPERSE26000, SOLSPERSE27000, SOLSPERSE28000, SOLSPERSE31845, SOSPELSPERSERSE 32000, SOSPERSE 32500, SOLSPERSE32550, SOLSE 32560600, SOLSE 35500, SOLSE LSE 35500, SOLSE 410500, SOLSE 35500, SOLSE 410200, SOLSE 71500, SOLSE 410500, SOLSE LSE 35500, SOLSE 71500, SOLSE LSE 35500, SOLSE 33200, SOLSE 35500, SOLSE LSE 35500, SOLSE LSE 3300, SOLSE 33000, SOLSE LSE 33500, SOLSE LSE 3300, SOLSE LSE 33200, SOLSE LSE 3300, SOLSE 33500, SOLSE LSE 3, SOLSE LSE 3, SOLSE LSE 3, SOLSE LSE 3, SOLSE LS;

SOLPLUS (registered trademark) (the same applies hereinafter) D510, SOLPLUS D520, SOLPLUS D530, SOLPLUS D540, SOLPLUS sp 310, SOLPLUS sk500, SOLPLUS sl300, SOLPLUS sl400, SOLPLUS sr700, and the like;

disperbyk (registered trademark) manufactured by BYK-Chemie JAPAN corporation, Disperbyk102, Disperbyk103, Disperbyk106, Disperbyk107, Disperbyk108, Disperbyk109, Disperbyk110, Disperbyk111, Disperbyk112, Disperbyk116, Disperbyk130, Disperbyk140, Disperbyk142, Disperbyk145, Disperbyk154, Disperbyk161, Disperbyk162, Disperbyk163, Disperbyk164, Disperbyk165, Disperbyk166, Disperbyk167, Disperbyk168, Disperbyk170, Disperbyk171, Disperbyk174, Disperbyk180, Disperbyk181, Disperbyk 215181, disperby2095, disperby215181, disperby2095, Disperbyk 2022, Disperbyk185, Disperbyk 2022, Disperbyk, disperb;

Anti-Terra (registered trademark) (the same applies hereinafter) -U, Anti-Terra203, Anti-Terra204, and the like;

BYK (registered trademark) (the same applies hereinafter) P104, BYK-P104S, BYK-P105, BYK-P9050, BYK-P9051, BYK-P9060, BYK-P9065, BYK-P9080, BYK-051, BYK-052, BYK-053, BYK-054, BYK-055, BYK-057, BYK-063, BYK-065, BYK-066-067A, BYK-077, BYK-088, BYK-141, BYK-220-S, BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-315, BYK-320, K-322, BK-323, BYK-325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-340, BYK-347, BYK-348, K-345, BYK-K-346, BYK-, BYK-350, BYK-354, BYK-355, BYK-358N, BYK-361, 361N, BYK-370, BYK-375, BYK-377, BYK-378, BYK-380N, BYK-381, BYK-392, BYK-410, BYK-425, BYK-430, BYK-1752, BYK-4510, BYK-6919, BYK-9076, BYK-9077, BYK-W909, BYK-W935, BYK-W940, BYK-W961, BYK-W966, BYK-W969, BYK-W972, BYK-W980, BYK-W985, BYK-W995, BYK-W996, BYK-W9010, BYK-Dynwet800, BYK-Sillean 0, BYK-UV-3500, BYK-UV-3510, BYK-3570, etc.;

EFKA (registered trademark) (the same applies hereinafter) 2020, EFKA2025, EFKA3030, EFKA3031, EFKA3236, EFKA4008, EFKA4009, EFKA4010, EFKA4015, EFKA4046, EFKA4047, EFKA4060, EFKA4080, EFKA7462, EFKA4020, EFKA4050, EFKA4055, EFKA4300, ka EFKA4310, EFKA4320, EFKA4400, EFKA4401, EFKA4402, EFKA4403, EFKA4300, EFKA4320, EFKA4330, EFKA4340, EFKA5066, EFKA5220, EFKA6220, EFKA6225, EFKA6230, EFKA6700, EFKA6780, EFKA6782, EFKA 85efka 03;

JONCRYL (registered trademark) (the same shall apply hereinafter) 67, JONCRYL678, JONCRYL586, JONCRYL611, JONCRYL680, JONCRYL682, JONCRYL690, JONCRYL819, JONCRYL-JDX5050, etc., manufactured by BASF Japan K.K.;

TERPLUS (registered trademark) (the same applies hereinafter) MD 1000, TERPLUS D1180, TERPLUS D1130 and the like manufactured by Otsuka chemical Co., Ltd;

AJISPER (registered trademark) (the same shall apply hereinafter) PB-711, AJISPER PB-821, AJISPER PB-822, etc., manufactured by Ajine Techno;

DISPERLON (registered trademark) (the same applies hereinafter) 1751N, DISPERLON1831, DISPERLON 1850, DISPERLON 1860, DISPERLON 1934, DISPERLON DA-400N, DISPERLONDA-703-50, DISPERLON DA-325, DISPERLON DA-375, DISPERLON DA-550, DISPERLON DA-705, DISPERLON DA-725, DISPERLON DA-1401, DISPERLON DA-7301, DISPERLON DN-900, DISPERLON NS-5210, DISPERLON NVI-8514L and the like, manufactured by NANOCHEMICAL CROGENS;

ARUFON (registered trademark) (the same applies hereinafter) manufactured by Toyo Synthesis Co., Ltd., UC-3000, ARUFON UF-5022, ARUFON UG-4010, ARUFON UG-4035, ARUFONUG-4070, and the like.

(3) Solvent(s)

In the near-infrared curable ink composition of the present invention, it is preferable to use a solvent together with a monomer of the thermosetting resin in an uncured state.

In this case, as the solvent of the near-infrared ray curable ink composition, a reactive organic solvent having a functional group such as an epoxy group which reacts with a monomer or oligomer of the thermosetting resin contained in the resin in an uncured state at the time of curing reaction of the thermosetting resin described below is preferably used.

The viscosity of the near-infrared curable ink composition can be appropriately adjusted by adding the solvent. As a result, the coatability and the smoothness of the coating film can be easily ensured.

Examples of the solvent of the near-infrared-curable ink composition of the present invention include water, alcohols such as methanol, ethanol, propanol, butanol, isopropanol, isobutanol, and diacetone alcohol, ethers such as methyl ether, ethyl ether, and propyl ether, esters, ketones such as acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, and isobutyl ketone, and various organic solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, polyethylene glycol, and polypropylene glycol.

[e] Near-infrared curable ink composition

As described above, the near-infrared curable ink composition of the present invention can be obtained by adding the composite tungsten oxide fine particles of the present invention to an uncured thermosetting resin, or by dispersing the composite tungsten oxide fine particles of the present invention in an appropriate solvent and then adding the uncured thermosetting resin. The near-infrared-curable ink composition of the present invention has excellent adhesion to a predetermined substrate when the composition is placed on the substrate and cured by irradiation with near infrared light.

The near-infrared curable ink composition of the present invention is preferably used in the following photofabrication method, in addition to known ink applications: the coating was applied in a predetermined amount, and irradiated with near infrared rays to be cured and laminated, thereby forming the following 3-dimensional object.

As described above, a near-infrared-curable ink composition in which the solvent is removed from the near-infrared-curable ink composition containing the composite tungsten oxide fine particles and containing the solvent, the dispersant, and the uncured thermosetting resin is preferably configured; alternatively, a near-infrared curable ink composition containing composite tungsten oxide fine particles and further containing a dispersant and an uncured thermosetting resin is preferably obtained without using a solvent.

The near-infrared curable ink composition containing the composite tungsten oxide fine particles, the dispersant and the uncured thermosetting resin without using a solvent can omit the steps related to solvent volatilization in the subsequent steps, and has high curing reaction efficiency.

On the other hand, the method for removing the solvent is not particularly limited, and a heating distillation method or the like in which a reduced pressure operation is added may be used.

The amount of the composite tungsten oxide fine particles contained in the near-infrared curable ink of the present invention may be an amount that allows the thermosetting resin that is not cured at the time of curing reaction to be properly added. Therefore, the amount of the composite tungsten oxide fine particles per coated area of the near-infrared ray-curable ink may be determined in consideration of the coating thickness of the near-infrared ray-curable ink.

The method for dispersing the composite tungsten oxide fine particles in the solvent is not particularly limited, and a wet media mill is preferably used. Here, at this time, a trial dispersion was previously carried out to determine that the composite tungsten oxide fine particles can be given an average particle diameter of 100nm or less and a lattice constant with the a-axis of

Above and

in the following, the c-axis is

Above and

hereinafter, [ c-axis lattice constant/a-axis lattice constant ] is more preferable]A value of (D) is 1.0221 or more and 1.0289 or less.

[2] Near-infrared cured product and stereolithography method

Since the near-infrared curable ink of the present invention has visible light transmittance, the near-infrared curable ink composition of the present invention can be cured by applying a predetermined amount of the ink composition to obtain a coating film and irradiating the coating film with near-infrared light, thereby obtaining the near-infrared curable film of the present invention which exhibits excellent adhesion to a predetermined substrate. Further, a colored film can be easily obtained by adding at least 1 or more of various pigments or dyes to the near-infrared ray curable ink. Since the composite tungsten oxide fine particles in the colored film hardly affect the color tone, the colored film can be used for a color filter of a liquid crystal display or the like.

The reason why excellent adhesion can be obtained is that the composite tungsten oxide fine particles absorb irradiated near infrared rays to generate heat, and the thermal energy of the heat generation accelerates a polymerization reaction, a condensation reaction, an addition reaction, or the like by a monomer, an oligomer, or the like contained in the uncured thermosetting resin to cause a curing reaction of the thermosetting resin. In addition, the solvent is volatilized by heat generation of the composite tungsten oxide fine particles due to irradiation with near infrared rays.

On the other hand, even when the near-infrared ray cured film of the present invention is further irradiated with near-infrared rays, the cured film does not melt. The near-infrared ray cured film of the present invention contains a thermosetting resin obtained by curing an uncured thermosetting resin, and therefore does not melt even when the composite tungsten oxide fine particles generate heat by irradiation of near-infrared rays.

This characteristic is particularly effective in combination with the excellent adhesion to the substrate when applied to a stereolithography method in which a predetermined amount of the near-infrared curable ink composition of the present invention is cured and stacked, and the application of the near-infrared curable ink and the irradiation with near-infrared light are repeated and the stacking is repeated to form a three-dimensional object.

Of course, it is preferable that a predetermined amount of the near-infrared curable ink composition of the present invention is applied to a substrate and irradiated with near-infrared rays to be cured, thereby obtaining the near-infrared curable film of the present invention.

The material of the substrate used in the present invention is not particularly limited, and for example, paper, PET, acrylic, polyurethane, polycarbonate, polyethylene, ethylene-vinyl acetate copolymer, vinyl chloride, fluororesin, polyimide, polyacetal, polypropylene, nylon, and the like can be preferably used according to various purposes. In addition, glass may be preferably used in addition to paper and resin.

The method for curing the near-infrared-curable ink composition of the present invention is preferably irradiation with infrared rays, and more preferably irradiation with near-infrared rays. The near infrared ray has a high energy density, and can effectively impart energy required for curing the resin in the ink composition.

The near-infrared-curable ink composition of the present invention is preferably cured by a combination of infrared irradiation and any method selected from known methods. For example, a method such as heating, air blowing, or irradiation with electromagnetic waves may be used in combination with infrared irradiation.

In the present invention, infrared rays mean electromagnetic waves having a wavelength in the range of 0.1 to 1mm, near infrared rays mean infrared rays having a wavelength of 0.75 to 4 μm, and far infrared rays mean infrared rays having a wavelength of 4 to 1000 μm. In general, the effects of the present invention can be obtained when any infrared ray, i.e., far infrared ray or near infrared ray, is irradiated. In particular, when near-infrared rays are irradiated, the thermosetting resin can be cured in a shorter time and efficiently.

In the present invention, the microwave refers to an electromagnetic wave having a wavelength in the range of 1mm to 1 m.

The irradiated microwave preferably has a power of 200 to 1000W. When the power is 200W or more, vaporization of the organic solvent remaining in the ink is promoted, and when the power is 1000W or less, the irradiation condition is relatively mild and the substrate or the thermosetting resin is not deteriorated.

The preferable infrared ray irradiation time for the near-infrared ray-curable ink composition of the present invention varies depending on the energy or wavelength of irradiation, the composition of the near-infrared ray-curable ink, and the amount of the near-infrared ray-curable ink applied, but irradiation of 0.1 second or more is generally preferable. When the irradiation time is 0.1 second or more, the infrared irradiation can be performed within the range controlled to the preferable power. The solvent in the ink composition can be sufficiently dried by extending the irradiation time, but the irradiation time is preferably 30 seconds or less, more preferably 10 seconds or less, in consideration of entering the field of view of printing or coating at high speed.

The infrared radiation source may be obtained directly from a heat source, or may be obtained from a heat medium through which effective infrared radiation is obtained. For example, infrared rays can be obtained by heating a discharge lamp such as mercury, xenon, cesium, or sodium, a carbon dioxide gas laser, a resistor such as platinum, tungsten, nichrome, or cortael (chromium cobalt aluminum), or the like. As a preferred radiation source, a halogen lamp is exemplified. The halogen lamp has the advantages of good thermal efficiency, quick warm-up and the like.

The irradiation with infrared rays of the near-infrared ray-curable ink composition of the present invention may be performed from the near-infrared ray-curable ink application surface side or from the back surface side. The irradiation is preferably performed simultaneously from both sides, and is also preferably performed in combination with temperature-raising drying or air-blow drying. Further, it is more preferable to use a light collecting plate as needed. By combining these methods, they can be cured by irradiation with infrared light for a short time.

[ examples ]

The present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(1) Method for measuring crystal structure, method for calculating lattice constant and crystallite diameter

As a sample to be measured of the composite tungsten oxide fine particles, composite tungsten oxide fine particles obtained by removing the solvent from the dispersion for forming a near-infrared absorber were used. The X-ray diffraction pattern of the composite tungsten oxide fine particles was measured by a powder X-ray diffraction method (θ -2 θ method) using a powder X-ray diffraction apparatus (X \ Pert-PRO/MPD manufactured by PANalytical, inc., of mingri (Spectris)). The crystal structure contained in the fine particles was determined from the obtained X-ray diffraction pattern, and the lattice constant and the crystallite diameter were calculated using the rietveld method (rietveld method).

(2) Dispersed particle size

The dispersion particle diameter of the fine particles in the composite tungsten oxide fine particle dispersion was measured by using ELS-8000 manufactured by Otsuka electronics corporation, and disturbance of the scattered light of the laser beam was observed, and an autocorrelation function was obtained by a dynamic light scattering method (photon correlation method), and an average particle diameter (hydrodynamic diameter) was calculated by an integration method.

(3) Evaluation of cured film containing composite tungsten oxide Fine particles

A blue plate glass plate having a thickness of 3mm was coated with a near-infrared ray-curable ink composition, and irradiated with near-infrared rays to prepare a cured film containing composite tungsten oxide fine particles. The optical properties of the cured film were measured using a spectrophotometer U-4100 (manufactured by Hitachi, Ltd.). The visible light transmittance was measured according to JIS R3106: 1998.

(4) Average particle diameter in cured film containing composite tungsten oxide fine particles

The average particle diameter of the composite tungsten oxide fine particles dispersed in the near-infrared ray-curable ink composition was measured by observing a transmission electron microscope image of a cross section of the cured film. The transmission electron microscope image was observed using a transmission electron microscope (HF-2200 manufactured by Hitachi-Hightech K.K.). The transmission electron microscope image was processed by an image processing apparatus, and the particle diameters of 100 composite tungsten oxide fine particles were measured, and the average value thereof was defined as the average particle diameter.

[ example 1]

Cesium carbonate (Cs) was dissolved in 6.70kg of water₂CO₃)7.43kg of solution was obtained. Adding the solution to tungstic acid (H)₂WO₄)34.57kg, and mixed well with stirring, then stirred and dried (molar ratio of W to Cs corresponds to 1: 0.33). Supplying N to the dried product₂5% by volume H of gas as carrier₂Heating the mixture at 800 ℃ for 5.5 hours while heating the mixture, and then switching the supply gas to N alone₂The temperature of the gas was lowered to room temperature to obtain composite tungsten oxide particles (hereinafter referred to as particles a).

A mixture was obtained by mixing 20 parts by mass of the particles a, 65 parts by mass of methyl isobutyl ketone, and 15 parts by mass of an acrylic dispersant. The mixture was charged to the addition of 0.3mm phi ZrO₂Paint dispersing machine for beads (manufactured by Seiko Seisakusho K.K.)Manufactured), and subjected to pulverization and dispersion treatment for 7 hours to obtain a fine particle dispersion (hereinafter referred to as fine particle dispersion a) of fine particles a (hereinafter referred to as fine particles a). In this case, ZrO 0.3 mm. phi. was used in an amount of 100 parts by mass of the mixture₂The beads were pulverized and dispersed in 300 parts by mass.

Here, the dispersed particle diameter of the fine particles a in the fine particle dispersion a was measured by using a particle diameter measuring apparatus according to the dynamic light scattering method (ELS-8000 manufactured by Otsuka Denshi Co., Ltd.), and as a result, it was 70 nm. Further, the lattice constant of the fine particles a after the solvent was removed from the fine particle dispersion liquid a was measured, and the a-axis was

c axis is

In addition, the crystallite diameter was 24 nm. Furthermore, a hexagonal crystal structure was confirmed.

The near-infrared curable ink (hereinafter referred to as ink a) of example 1 was prepared by mixing 25 parts by mass of the fine particle dispersion a with 75 parts by mass of a commercially available one-pack thermosetting resin-containing thermosetting ink (MEG ScreenInk (medium) manufactured by imperial ink co., ltd.).

Ink A was applied to a 3mm thick blue plate glass by using a bar coater (No.10), LINE HEATER HYP-14N (output: 980W) manufactured by HYBEC corporation as a near infrared ray irradiation source was set at a height of 5cm from the applied surface, and the cured film of example 1 (hereinafter referred to as cured film A) was obtained by irradiating with near infrared ray for 10 seconds.

The average particle diameter of the composite tungsten oxide fine particles dispersed in the cured film a was calculated by an image processing apparatus using a transmission electron microscope image, and the result was 25 nm.

The adhesion of the cured film a was evaluated by the following method.

100 crosshatch cuts were cut out using a cutting guide with a gap interval of 1mm, an 18mm wide tape (manufactured by NICIBAN corporation) CELLOTAPE (registered trademark) CT-18) was attached to the cut surfaces of the crosshatch, and the tape was completely adhered by 20 times of back and forth movement using a 2.0kg roller, and then rapidly peeled at a peeling angle of 180 degrees, and the number of the peeled crosshatch was counted.

The number of squares peeled off was 0.

The cured film a was not remelted even when irradiated with near infrared rays for 20 seconds under the same conditions as those for curing the near infrared ray-curable ink.

The results are shown in tables 1 and 2.

[ example 2]

Cs tungsten oxide fine particles (hereinafter referred to as fine particles b) of example 2 were obtained in the same manner as in example 1 except that specified amounts of tungstic acid and cesium carbonate were weighed and the molar ratio of W to Cs was set to 1: 0.31.

A dispersion of fine particles b (hereinafter referred to as fine particle dispersion b) was obtained in the same manner as in example 1, except that fine particles b were used instead of fine particles a.

Then, a near-infrared curable ink (hereinafter referred to as ink B) of example 2 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid B was used in place of the fine particle dispersion liquid a.

A cured film of example 2 (hereinafter referred to as cured film B) was obtained in the same manner as in example 1, except that ink B was used instead of ink a.

The fine particle dispersion B and the cured film B were evaluated in the same manner as in example 1. In addition, a hexagonal crystal structure was confirmed in the composite tungsten oxide fine particle sample.

The results are shown in tables 1 and 2.

[ example 3]

Cs tungsten oxide fine particles (hereinafter referred to as fine particles c) of example 3 were obtained in the same manner as in example 1, except that predetermined amounts of tungstic acid and cesium carbonate were weighed and the molar ratio of W to Cs was 1: 0.35.

A dispersion of fine particles c (hereinafter referred to as fine particle dispersion c) was obtained in the same manner as in example 1, except that the fine particles c were used instead of the fine particles a.

Then, a near-infrared curable ink (hereinafter referred to as ink C) of example 3 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid C was used instead of the fine particle dispersion liquid a.

A cured film (hereinafter referred to as cured film C) of example 3 was obtained in the same manner as in example 1, except that ink C was used instead of ink a.

The fine particle dispersion C and the cured film C were evaluated in the same manner as in example 1. In addition, a hexagonal crystal structure was confirmed in the composite tungsten oxide fine particle sample.

The results are shown in tables 1 and 2.

[ example 4]

Cs tungsten oxide fine particles (hereinafter referred to as fine particles d) of example 4 were obtained in the same manner as in example 1, except that predetermined amounts of tungstic acid and cesium carbonate were weighed and the molar ratio of W to Cs was set to 1: 0.37.

A dispersion of fine particles d (hereinafter referred to as fine particle dispersion d) was obtained in the same manner as in example 1, except that fine particles d were used instead of fine particles a.

Then, a near-infrared curable ink (hereinafter referred to as ink D) of example 4 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid D was used instead of the fine particle dispersion liquid a.

A cured film of example 4 (hereinafter referred to as cured film D) was obtained in the same manner as in example 1, except that ink D was used instead of ink a.

The fine particle dispersion D and the cured film D were evaluated in the same manner as in example 1. In addition, a hexagonal crystal structure was confirmed in the composite tungsten oxide fine particle sample.

The results are shown in tables 1 and 2.

[ example 5]

Cs tungsten oxide fine particles (hereinafter referred to as fine particles e) of example 5 were obtained in the same manner as in example 1 except that specified amounts of tungstic acid and cesium carbonate were weighed and the molar ratio of W to Cs was set to 1: 0.21.

A dispersion of fine particles e (hereinafter referred to as fine particle dispersion e) was obtained in the same manner as in example 1, except that fine particles e were used instead of fine particles a.

Then, a near-infrared curable ink (hereinafter referred to as ink E) of example 5 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid E was used instead of the fine particle dispersion liquid a.

A cured film of example 5 (hereinafter referred to as cured film E) was obtained in the same manner as in example 1, except that ink E was used instead of ink a.

The fine particle dispersion E and the cured film E were evaluated in the same manner as in example 1. In addition, a hexagonal crystal structure was confirmed in the composite tungsten oxide fine particle sample.

The results are shown in tables 1 and 2.

[ example 6]

One side is supplied with N₂5% H with gas as carrier₂Cs tungsten oxide fine particles (hereinafter referred to as fine particles f) of example 6 were obtained in the same manner as in example 1, except that the gas was baked at 550 ℃ for 9.0 hours.

A dispersion of fine particles f (hereinafter referred to as fine particle dispersion f) was obtained in the same manner as in example 1, except that the fine particles f were used instead of the fine particles a.

A near-infrared curable ink (hereinafter referred to as ink F) of example 6 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid F was used instead of the fine particle dispersion liquid a.

A cured film of example 6 (hereinafter referred to as cured film F) was obtained in the same manner as in example 1, except that ink F was used instead of ink a.

The fine particle dispersion liquid F and the cured film F were evaluated in the same manner as in example 1. In addition, a hexagonal crystal structure was confirmed in the composite tungsten oxide fine particle sample.

The results are shown in tables 1 and 2.

[ example 7]

A near-infrared curable ink (hereinafter referred to as ink G) of example 7 was prepared in the same manner as in example 1, except that 30 parts by mass of the fine particle dispersion liquid a was mixed with 70 parts by mass of a commercially available one-pack type thermosetting ink.

A cured film (hereinafter referred to as cured film G) of example 7 was obtained in the same manner as in example 1, except that ink G was used instead of ink a.

The cured film G was evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

[ example 8]

A near-infrared curable ink (hereinafter referred to as ink H) of example 8 was prepared in the same manner as in example 1, except that 35 parts by mass of the fine particle dispersion liquid a was mixed with 65 parts by mass of a commercially available one-pack type thermosetting ink.

A cured film (hereinafter referred to as a cured film H) of example 8 was obtained in the same manner as in example 1, except that the ink H was used instead of the ink a.

The cured film H was evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

[ example 9]

A near-infrared curable ink (hereinafter referred to as ink I) of example 9 was prepared in the same manner as in example 1, except that 25 parts by mass of the fine particle dispersion a, 37.5 parts by mass of the uncured bisphenol a epoxy resin, and 37.5 parts by mass of the curing agent to which the curing accelerator was added were mixed. The curing agent is a mixture of a phenol resin and imidazole (curing accelerator).

A cured film (hereinafter referred to as cured film I) of example 9 was obtained in the same manner as in example 1, except that ink I was used instead of ink a.

Cured film I was evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

[ example 10]

20 parts by mass of the particles a, 65 parts by mass of methyl isobutyl ketone, and 15 parts by mass of an acrylic dispersant were mixed to prepare a mixture. Filling the mixtureTo add 0.3mm phi ZrO₂The beads were pulverized and dispersed for 20 minutes by a paint dispersing machine (manufactured by suyota ferrite co., ltd.) to obtain a fine particle dispersion of fine particles a (hereinafter referred to as a fine particle dispersion p). In this case, 300 parts by mass of 0.3 mm. phi. ZrO was used with respect to 100 parts by mass of the mixture₂The beads were pulverized and dispersed.

A near-infrared-curable ink (hereinafter referred to as ink P) of example 10 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid P was used instead of the fine particle dispersion liquid a.

A cured film (hereinafter referred to as cured film P) of example 10 was obtained in the same manner as in example 1, except that ink P was used instead of ink a.

The fine particle dispersion P and the cured film P were evaluated in the same manner as in example 1. In addition, a hexagonal crystal structure was confirmed in the composite tungsten oxide fine particle sample.

The results are shown in tables 1 and 2.

Comparative example 1

Cs tungsten oxide fine particles (hereinafter referred to as fine particles j) of comparative example 1 were obtained in the same manner as in example 1 except that specified amounts of tungstic acid and cesium carbonate were weighed and the molar ratio of W to Cs was 1: 0.15.

A dispersion of fine particles j (hereinafter referred to as a fine particle dispersion j) was obtained in the same manner as in example 1, except that the fine particles j were used instead of the fine particles a.

Then, a near-infrared-curable ink (hereinafter referred to as ink J) of comparative example 1 was prepared in the same manner as in example 1, except that the fine particle dispersion J was used instead of the fine particle dispersion a.

A cured film of comparative example 1 (hereinafter referred to as cured film J) was obtained in the same manner as in example 1, except that ink J was used instead of ink a.

The fine particle dispersion J and the cured film J were evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

Comparative example 2

Cs tungsten oxide fine particles (hereinafter referred to as fine particles k) of comparative example 2 were obtained in the same manner as in example 1, except that specified amounts of tungstic acid and cesium carbonate were weighed and the molar ratio of W to Cs was set to 1: 0.39.

A dispersion of fine particles k (hereinafter referred to as fine particle dispersion k) was obtained in the same manner as in example 1, except that fine particles k were used instead of fine particles a.

Then, a near-infrared curable ink (hereinafter referred to as ink K) of comparative example 2 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid K was used instead of the fine particle dispersion liquid a.

A cured film (hereinafter referred to as cured film K) of comparative example 2 was obtained in the same manner as in example 1, except that ink K was used instead of ink a.

The fine particle dispersion K and the cured film K were evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

Comparative example 3

Cs tungsten oxide fine particles (hereinafter referred to as fine particles 1) of comparative example 3 were obtained in the same manner as in example 1 except that specified amounts of tungstic acid and cesium carbonate were weighed so that the molar ratio of W to Cs was 1:0.23, and the particles were fired at a temperature of 400 ℃ for 5.5 hours.

Then, a near-infrared-curable ink (hereinafter referred to as ink L) of comparative example 3 was prepared in the same manner as in example 1, except that the fine particle dispersion L was used instead of the fine particle dispersion a.

A cured film of comparative example 3 (hereinafter referred to as cured film L) was obtained in the same manner as in example 1, except that ink L was used instead of ink a.

The fine particle dispersion L and the cured film L were evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

Comparative example 4

Cs tungsten oxide fine particles (hereinafter referred to as fine particles m) of comparative example 4 were obtained in the same manner as in example 1, except that specified amounts of tungstic acid and cesium carbonate were weighed so that the molar ratio of W to Cs was 1:0.23, and the particles were fired at 600 ℃ for 5.5 hours.

Then, 20 parts by mass of the fine particles m, 65 parts by mass of methyl isobutyl ketone, and 15 parts by mass of an acrylic dispersant were mixed to prepare a mixture. This mixture was charged into a paint dispersing machine (manufactured by suyota iron corporation) and subjected to a dispersing treatment for 10 minutes to obtain a dispersion of fine particles m (hereinafter referred to as fine particle dispersion m).

A near-infrared-curable ink (hereinafter referred to as ink M) of comparative example 4 was prepared in the same manner as in example 1, except that the fine particle dispersion M was used instead of the fine particle dispersion a.

A cured film of comparative example 4 (hereinafter referred to as cured film M) was obtained in the same manner as in example 1, except that ink M was used instead of ink a.

The fine particle dispersion M and the cured film M were evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

Comparative example 5

20 parts by mass of the fine particles a, 65 parts by mass of methyl isobutyl ketone, and 15 parts by mass of an acrylic dispersant were mixed to prepare a mixture. The mixture was charged to the addition of 0.3mm phi ZrO₂The beads were pulverized and dispersed for 50 hours by a paint dispersing machine (manufactured by suyota ferrite co., ltd.) to obtain a fine particle dispersion of fine particles a (hereinafter referred to as a fine particle dispersion n). In this case, ZrO 0.3 mm. phi. was used in an amount of 100 parts by mass of the mixture₂The beads were pulverized and dispersed in 300 parts by mass.

A near-infrared-curable ink (hereinafter referred to as ink N) of comparative example 5 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid N was used instead of the fine particle dispersion liquid a.

A cured film of comparative example 5 (hereinafter referred to as cured film N) was obtained in the same manner as in example 1, except that ink N was used instead of ink a.

The fine particle dispersion N and the cured film N were evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

Comparative example 6

20 parts by mass of the fine particles m, 65 parts by mass of methyl isobutyl ketone, and 15 parts by mass of an acrylic dispersant were mixed to prepare a mixture. The mixture was charged to the addition of 0.3mm phi ZrO₂The bead paint dispersion machine was pulverized and dispersed for 4 hours to obtain a dispersion of fine particles m (hereinafter referred to as fine particle dispersion o). In this case, ZrO 0.3 mm. phi. was used in an amount of 100 parts by mass of the mixture₂The beads were pulverized and dispersed in 300 parts by mass.

A near-infrared curable ink (hereinafter referred to as ink O) of comparative example 6 was prepared in the same manner as in example 1, except that the fine particle dispersion liquid O was used instead of the fine particle dispersion liquid a.

A cured film (hereinafter referred to as cured film O) of comparative example 6 was obtained in the same manner as in example 1, except that ink O was used instead of ink a.

The fine particle dispersion liquid O and the cured film O were evaluated in the same manner as in example 1.

The results are shown in tables 1 and 2.

[ conclusion ]

From the results of examples 1to 10 and comparative examples 1to 6 described above, it was confirmed that the cured films of examples 1to 10 all have good efficiency of absorbing light in the near infrared region and high adhesion to the substrate.

On the other hand, the cured films of comparative examples 1to 6 had low adhesion to the substrate and had insufficient near infrared ray characteristics.

Description of the symbols

1 … thermal plasma

2 … high-frequency coil

3 … sheath flow gas supply nozzle

4 … plasma gas supply nozzle

5 … raw material powder supply nozzle

6 … reaction vessel

7 … suction tube

8 … filter

Claims (19)

1. A near-infrared ray-curable ink composition comprising composite tungsten oxide fine particles having near-infrared ray absorbing ability and an uncured thermosetting resin, wherein,

the composite tungsten oxide fine particles are composite tungsten oxide fine particles containing a hexagonal crystal structure,

the a-axis of the lattice constant of the composite tungsten oxide fine particles is

Above and

in the following, the c-axis is

Above and

in the following, the following description is given,

the composite tungsten oxide fine particles have an average particle diameter of 100nm or less.

2. The near-infrared-curable ink composition according to claim 1, wherein the a-axis of the lattice constant of the composite tungsten oxide fine particles is

Above and

in the following, the c-axis is

Above and

the following.

3. The near-infrared-curable ink composition according to claim 1 or 2, wherein the composite tungsten oxide fine particles have an average particle diameter of 10nm or more and 100nm or less.

4. The near-infrared-curable ink composition according to any one of claims 1to 3, wherein the composite tungsten oxide fine particles have a crystallite diameter of 10nm or more and 100nm or less.

5. The near-infrared curable ink composition according to any one of claims 1to 4, further comprising a dispersant.

6. The near-infrared curable ink composition according to any one of claims 1to 5, further comprising a solvent.

7. The near-infrared curable ink composition according to any one of claims 1to 6, wherein the composite tungsten oxide is represented by the general formula MxWyOz (M element is at least 1 element selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb, W is tungsten, O is oxygen, and 0.001. ltoreq. x/y.ltoreq.1, 2.0. ltoreq. z/y.ltoreq.30).

8. The near-infrared-curable ink composition according to claim 7, wherein the composite tungsten oxide contains 1 or more composite tungsten oxides in which the M element is selected from Cs and Rb.

9. The near-infrared curable ink composition according to any one of claims 1to 8, wherein at least a part of the surface of the composite tungsten oxide fine particles is coated with a surface coating film, and the surface coating film contains at least 1 or more elements selected from the group consisting of Si, Ti, Zr, and Al.

10. The near-infrared curable ink composition according to claim 9, wherein the surface coating film contains an oxygen atom.

11. The near-infrared curable ink composition according to any one of claims 1to 10, further comprising at least one selected from the group consisting of an organic pigment, an inorganic pigment and a dye.

12. A near-infrared ray-curable film obtained by curing the near-infrared ray-curable ink composition according to any one of claims 1to 11 by irradiation with near-infrared rays.

13. A method of light sculpting, comprising: a coating material prepared by applying the near-infrared curable ink composition according to any one of claims 1to 11 to a substrate, and curing the coating material by irradiating the coating material with near-infrared light.

14. A process for producing a near-infrared-curable ink composition comprising composite tungsten oxide fine particles having near-infrared absorption ability, an uncured thermosetting resin, a dispersant and a solvent, wherein,

the composite tungsten oxide fine particles are composite tungsten oxide fine particles containing a hexagonal crystal structure,

the method comprises the following steps: the composite tungsten oxide fine particles are produced so that the lattice constant thereof is on the a-axis

Above and

in the following, the c-axis is

Above and

the following ranges are set forth below,

and a pulverization and dispersion treatment step of maintaining the range of the lattice constant of the composite tungsten oxide fine particles and making the average particle diameter to 100nm or less.

15. The method for producing a near-infrared-curable ink composition according to claim 14, wherein the composite tungsten oxide is represented by a general formula MxWyOz (M element is at least 1 element selected from H, He, alkali metal, alkaline earth metal, rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb, W is tungsten, O is oxygen, and 0.001. ltoreq. x/y.ltoreq.1, 2.0. ltoreq. z/y.ltoreq.30).

16. The method for producing a near-infrared-curable ink composition according to claim 14 or 15, wherein the composite tungsten oxide contains a composite tungsten oxide in which the M element is 1 or more selected from Cs and Rb.

17. The method for producing a near-infrared-curable ink composition according to any one of claims 14 to 16, wherein at least a part of the surface of the composite tungsten oxide fine particles is coated with a surface coating film, and the surface coating film contains 1 or more elements selected from Si, Ti, Zr, and Al.

18. The method for producing a near-infrared-curable ink composition according to claim 17, wherein the surface coating film contains an oxygen atom.

19. The method for producing a near-infrared-curable ink composition according to any one of claims 14 to 18, further comprising adding at least one kind selected from the group consisting of an organic pigment, an inorganic pigment and a dye to the near-infrared-curable ink composition.

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