JPWO2019188851A1 - Black ink composition for inkjet, light-shielding film and optical member, and image forming method - Google Patents

Abstract

One embodiment of the present invention contains carbon black particles, titanium dioxide particles, and a basic dispersant, and the content of the titanium dioxide particles is 15% by mass or more and 45% by mass with respect to the total mass of the composition. % Or less, and the mass ratio of the content of titanium dioxide particles to the content of carbon black particles is 2.0 or more and 15.0 or less, as well as a black ink composition for inkjet, a light-shielding film, an optical member, and an image. A forming method is provided.

Description

The present disclosure relates to a black ink composition for an inkjet, a light-shielding film and an optical member, and an image forming method.

The light-shielding film or member is used in various fields, and is used not only for blocking light but also for absorbing light and for providing a decorative function, and has a wide variety of uses. There is.

The light-shielding film is also used, for example, in optical applications.
A lens is known as an example of an optical application, and a light-shielding film is attached to the side surface of the lens, that is, the outer peripheral surface of the lens when viewed with the incident direction of light as an axis. By attaching a light-shielding film on the outer peripheral surface of the lens, the difference in refraction at the interface between the lens and the light-shielding film is smaller than that at the interface between the lens and air. Therefore, for example, light obliquely incident on the lens is emitted from the side surface of the lens. It is possible to reduce the internal reflection that occurs when the lens hits. This makes it possible to suppress optical failures such as flares and ghosts that are likely to occur in the image.

In recent years, as optical glass, glass having a high refractive index of 1.8 or more has been developed and used. When this optical glass is used for a lens, for example, the difference in refractive index between the lens and the light-shielding film becomes wider than before, and as a result, even if the lens has a high refractive index, it is a high-refractive-index lens. It is presumed that the performance as a lens has not been fully exhibited.

As a technique related to the above, optics containing at least a resin and a colorant and having an average extinction coefficient of 0.03 or more and 0.15 or less, which is an average value of the extinction coefficient at a wavelength of 400 nm to 700 nm of the entire light-shielding film. A light-shielding film for an element is disclosed (see, for example, Japanese Patent Application Laid-Open No. 2011-186437).

As described above, when a light-shielding film is attached to a lens, which is an example of an optical member, to suppress optical failure, it is important to reduce the difference in refractive index between the lens and the light-shielding film. However, when an optical glass having a refractive index of 1.8 or more is used, it is necessary to increase the refractive index of the light-shielding film in order to keep the difference in refractive index between the lens and the lens small.

In the above-mentioned Japanese Patent Application Laid-Open No. 2011-186437, a dye is used as a main component and a black pigment is added as necessary to realize black color, and if necessary, non-black particles are contained within a range not exceeding the amount of the black pigment. The examples given are disclosed.
With such a composition, although the absorption of the light-shielding film is high, the effect of improving the refractive index cannot be expected, so it is presumed that the internal reflection at the interface between the lens and the light-shielding film is not suppressed. Further, since the light-shielding film described in JP-A-2011-186437 is a film formed by a reactive epoxy-based coating film, this coating film is simply applied to a film-forming method using an inkjet method. It is difficult to form a film.

The present disclosure has been made in view of the above.
An object to be solved by one embodiment of the present invention is to provide a black ink composition for an inkjet, which has a black color tone and forms a film having a high refractive index (preferably 1.75 or more). It is in.
An object to be solved by another embodiment of the present invention is to provide a light-shielding film and an optical member having a blackish color tone and a high refractive index (preferably 1.75 or more), and an image forming method. ..

Specific means for solving the problem include the following aspects.
<1> Containing carbon black particles, titanium dioxide particles, and a basic dispersant,
The content of titanium dioxide particles is 15% by mass or more and 45% by mass or less with respect to the total mass of the composition, and the mass ratio of the content of titanium dioxide particles to the content of carbon black particles is 2.0 or more and 15%. A black ink composition for inkjet having a mass ratio of 0.0 or less.
<2> The basic dispersant is the black ink composition for an inkjet according to <1>, wherein the amine value is 10 mgKOH / g or more and 80 mgKOH / g or less.
<3> The titanium dioxide particles are the black ink composition for an inkjet according to <1> or <2>, wherein the average primary particle diameter is 10 nm or more and 100 nm or less.
<4> The black ink composition for an inkjet according to any one of <1> to <3>, wherein the content of the carbon black particles is 1% by mass or more and 6% by mass or less with respect to the total mass of the composition. It is a thing.
<5> The black ink composition for an inkjet according to any one of <1> to <4>, which further contains an organic solvent having a boiling point of 120 ° C. or higher.
<6> The black ink composition for an inkjet according to <5>, wherein the content of the organic solvent is 10% by mass or more and 55% by mass or less with respect to the total mass of the composition.
<7> At least two kinds of organic solvents having a boiling point of 120 ° C. or higher are contained, and among the organic solvents having a boiling point of 120 ° C. or higher, the boiling point of one organic solvent is BPa and the boiling point of the other organic solvent is BPb. If this is the case, the surface tension of one of the organic solvents satisfying the relationship of 120 ° C. <BPa <BPb <250 ° C. and having a boiling point of 120 ° C. or higher in mN / m is defined as γa, and the other. The black ink composition for inkjet according to <5> or <6>, which satisfies the relationship of γa <γb, when the surface tension of the organic solvent having mN / m as a unit is γb. ..
<8> γa and γb are the black ink compositions for inkjet according to <7>, which satisfy the relationship represented by γa <30 mN / m <γb.
<9> The black ink composition for an inkjet according to any one of <1> to <8>, which further contains at least one curable compound selected from a photocurable monomer and a photocurable resin. ..

<10> A light-shielding film which is a cured product of the black ink composition for inkjet according to any one of <1> to <9>.
<11> The light-shielding film according to <10>, which has a refractive index of 1.75 or more.
<12> The light-shielding film according to <10> or <11>, wherein the content of the dye is less than 10% by mass.
<13> The light-shielding film according to any one of <10> to <12> used for an optical member.
<14> An optical member including a base material and the light-shielding film according to any one of <10> to <13>.
<15> The optical member according to <14>, wherein the base material is a glass base material or a resin base material, and the outer peripheral surface of the glass base material or the resin base material has a light-shielding film when the thickness direction is the axis.
<16> An image forming method comprising a step of applying the black ink composition for an inkjet according to any one of <1> to <9> on a base material by an inkjet method.

According to one embodiment of the present invention, there is provided a black ink composition for an inkjet that has a black color tone and forms a film having a high refractive index (preferably 1.75 or more).
According to another embodiment of the present invention, there is provided a light-shielding film having a blackish color tone and a high refractive index (preferably 1.75 or more), an optical member, and an image forming method.

Hereinafter, the black ink composition for inkjet, the light-shielding film and the optical member, and the image forming method will be described in detail.

In the present specification, "black" or "black" means that the optical density (OD) per 1 μm of thickness is 0.1 or more (OD ≧ 0.1 / μm), and the absorbance at 580 nm with respect to the absorbance at 480 nm. The ratio of is 0.3 to 3.

In the present specification, the numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.

Further, in the present specification, the amount of each component in the composition is the sum of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. Means quantity.

In addition, in this specification, "mass%" and "weight%" are synonymous, and "mass part" and "weight part" are synonymous. Further, in the present specification, a combination of two or more preferred embodiments is a more preferred embodiment.

<Black ink composition for inkjet>
The black ink composition for an inkjet of the present disclosure (hereinafter, also simply referred to as "black ink" or "black ink" of the present disclosure) includes carbon black particles, titanium dioxide particles, a basic dispersant, and the like. The content of the titanium dioxide particles is 15% by mass or more and 45% by mass or less with respect to the total mass of the composition, and the mass ratio of the content of the titanium dioxide particles to the content of the carbon black particles is set to 2. It is set to 0 or more and 15.0 or less.

The light-shielding film has come to be used in a wide variety of applications, and is also used in, for example, optical applications. A lens known as an example of optical applications is provided with a light-shielding film on the side surface of the lens, that is, the outer peripheral surface when viewed with the incident direction of light as the axis, thereby suppressing the reflection of light on the inner surface in the lens. In order to suppress this internal reflection, it is important that the refractive index of the lens and the refractive index of the light-shielding film are close to each other, and that the light-shielding film itself does not easily reflect light.
On the other hand, in recent years, a glass having a high refractive index of 1.8 or more has been developed as an optical glass. When this optical glass is used as a lens, for example, it is presumed that the performance as a high-refractive-index lens cannot be fully exhibited as a result of the widening difference in the refractive index between the optical glass and the light-shielding film.
Among the conventional techniques, the light-shielding film and the like described in Japanese Patent Application Laid-Open No. 2011-186437 are considered to be good in terms of light absorption of the light-shielding film itself, but suppress internal reflection at the interface between the lens and the light-shielding film. It is presumed that there is room for improvement in the effect. In addition, the technique described in JP-A-2011-186437 is not suitable for a film-forming method using an inkjet method because it is a film-forming method using a reactive epoxy-based paint.

In view of the above, in the present disclosure, as an ink composition having a black color tone applicable to the inkjet method, a specific amount of titanium dioxide particles are included from the viewpoint of increasing the refractive index while having a black color tone, and , Carbon black particles and titanium dioxide particles are contained in a proportion of titanium dioxide particles higher than that of carbon black particles. In addition, a basic dispersant is selectively used from the viewpoint of satisfactorily dispersing two different types of carbon black particles and titanium dioxide particles.
As a result, it is possible to achieve both inkjet suitability and high refractive index while maintaining a black color tone. In other words, the black ink composition for inkjet of the present disclosure can ensure the suitability for inkjet, and dramatically improve the refractive index of the film while providing the film with light absorption (light shielding property). Can be enhanced.

Hereinafter, each component contained in the black ink of the present disclosure will be described.
-Carbon black particles-
The black ink of the present disclosure contains at least one kind of carbon black particles.
The black ink of the present disclosure contains carbon black as a particle component as a black coloring component.

The carbon black is not particularly limited, and a known carbon black can be used. Examples of the carbon black include those produced by a known method such as a contact method, a furnace method, and a thermal method.
Specific examples of carbon black, Raven1250, Raven1200, Raven1190 ULTRA, Raven1170, Raven1255, Raven1080ULTRA, Raven1060ULTRA, Raven1040, Raven1035, Raven1020, Raven1000, Raven900, Raven890, Raven850, Raven780ULTRA, Raven860Ultra, Raven520, Raven500, Raven450, Raven460, Raven415 , Raven14, Conductex7055 Ultra (above, Columbian Carbon), Regal400R, Regal330R, Regal660R, Mogul L, Black Pearls L, Regal99, Regal350, MONARCH280, MONARCH120, MONARCH120 (above, MONARCH120) S170, Printex35, Printex U, Printex V, Printex140U, Printex140V, Printex300, Printex25, Printex200, PrintexA, PrintexG, Special Black 5, Special Black 4A, Special Black4, Special Black550, Special Black 350, Special Black250, Special Black100, NEROX3500, NEROX1000, NEROX2500 (all manufactured by Orion Engineered Carbons), No. 10, No. 20, No. 25, No. 33, No. 40, No. 45, No. 47, No. 52, No. 85, No. 95, No. 260, MA7, MA8, MA11, MA77, MA100, MA220, MA230, MA600 (all manufactured by Mitsubishi Chemical Corporation) and the like can be mentioned.
However, the present disclosure is not limited to these.

The average primary particle size of carbon black is preferably 20 nm to 100 nm, more preferably 30 nm to 80 nm.
The average primary particle size is the particle size (equivalent to an area circle) of 1000 primary particles arbitrarily selected from images taken with a transmission electron microscope TEM2010 (pressurized voltage 200 kV; manufactured by JEOL Ltd.). It is a value that is measured and calculated as the arithmetic average. That is, the average primary particle diameter represents the arithmetic mean particle diameter of the area equivalent circle diameter.

The amount of dibutyl phthalate (DBP) absorbed by carbon black is not particularly limited, and is preferably 30 ml / 100 g or more and 200 ml / 100 g or less, more preferably 40 ml / 100 g or more and 150 ml / 100 g or less, from the viewpoint of color tone and ink concentration. preferable.
The amount of DBP absorbed is a value measured by the JIS K6221 A method (1982).

The BET specific surface area of carbon black is preferably 30 m ² / g or more and 450 m ² / g or less, and more preferably 200 m ² / g or more and 400 m ² / g or less, from the viewpoint of ink concentration and storage stability.

The content of the carbon black particles is preferably 1% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 6% by mass or less, based on the total mass of the black ink composition for inkjet. It is more preferably 1% by mass or more and 4% by mass or less.
When the content of the carbon black particles is 1% by mass or more, it is easy to adjust to a desired black color tone, and for example, when forming a light-shielding film, it is easy to impart light-shielding performance. Further, when the content of the carbon black particles is 10% by mass or less, good stability over time can be easily obtained. The content of the carbon black particles is more preferably 7% by mass or less in terms of stability over time.

-Titanium dioxide particles-
The black ink of the present disclosure contains at least one kind of titanium dioxide particles.
The black ink of the present disclosure contains titanium dioxide as a particle component, and the shape of the titanium dioxide particles contained therein is not particularly limited, and may be granular or needle-shaped.

The crystal structure of titanium dioxide includes rutile type (tetragonal crystal), anatase type (tetragonal crystal), and brookite type (orthorhombic crystal), and is not particularly limited. Among them, the preferable titanium dioxide is rutile-type titanium dioxide from the viewpoint of crystal stability and availability.
Titanium dioxide can be produced by a vapor phase method or a liquid phase method. Titanium dioxide produced by the vapor phase method is preferable because it is easy to obtain a highly crystalline product. Further, the titanium dioxide can be either untreated or surface-treated. When titanium dioxide is surface-treated, the surface treatment includes surface treatment with an inorganic substance such as alumina (Al ₂ O ₃ ) and silica (SiO ₂ ), or titanium coupling agent, silane coupling agent, silicone oil, etc. Examples include surface treatment with an organic substance.

Since titanium dioxide has organic matter decomposability due to photocatalytic activity, the surface of the particles is surface-treated with an inorganic oxide such as alumina, or coated with an inorganic hydrate containing zinc, magnesium, zirconium or the like. Is preferable. Further, from the viewpoint of adjusting the acidic or basic state of the particle surface and the durability, it is preferable that the surface is treated with alumina and silica in combination.

As the titanium dioxide, a commercially available product on the market may be used.
Examples of commercially available rutile-type titanium dioxide products include typake (registered trademark) R series (rutile-type; for example, R-550, R-630, R-680, R-820) and typake CR series manufactured by Ishihara Sangyo Co., Ltd. (Rutile type; for example, CR-50, CR-80), PF series, ultrafine titanium oxide TTO series (rutile type; for example, TTO-51 series (eg, TTO-51A, TTO-51B, etc.), TTO- 55 series (eg TTO-55A, TTO-55B, etc.), TTO-S series (eg TTO-S-1, etc.), TTO-V series (eg TTO-V-3, etc.), TTO-F series, TTO-W-5 series), trade name manufactured by Sakai Chemical Industry Co., Ltd .: R series, JR series manufactured by Teika Co., Ltd., MT series, fine particle titanium oxide MT series (for example, MT-01, MT-10EX, MT-) 05, MT-100S, MT-100SA, MT-500SA, MT-150EX, MT-150W), KURONOS KR series manufactured by Titanium Industry Co., Ltd., TR series manufactured by Fuji Titanium Industry Co., Ltd. and the like.

The average primary particle diameter of the titanium dioxide particles is preferably 10 nm or more and 300 nm or less, and from the viewpoint of high transparency, less influence on color tone and refractive index, and excellent dispersibility, it is 10 nm or more and 100 nm or less. It is preferably 10 nm or more and 80 nm or less, and more preferably 30 nm or more and 80 nm or less.
The average primary particle size of titanium dioxide is the particle size (equivalent to an area circle) of 1000 primary particles arbitrarily selected from images taken using a transmission electron microscope TEM2010 (pressurized voltage 200 kV; manufactured by JEOL Ltd.). It is a value calculated as the arithmetic mean by measuring the diameter). The average primary particle diameter here represents the arithmetic mean particle diameter of the diameter equivalent to the area circle.

The mass ratio of the content of titanium dioxide particles to the content of carbon black particles described above is in the range of 2.0 or more and 15.0 or less.
When the content ratio of the titanium dioxide particles to the carbon black particles is 2.0 or more, a high refractive index (refractive index of 1.75 or more) can be easily obtained, and good stability over time can be easily obtained. Further, when the content ratio of the titanium dioxide particles to the carbon black particles is 15.0 or less, the influence of the carbon black particles on the black coloring is small, and the desired black tone can be easily obtained, so that the light-shielding property can be easily maintained. ..
Among them, the content ratio of the titanium dioxide particles to the carbon black particles is more preferably 3.0 or more and 13.0 or less, and further preferably 3.0 or more and 10.0 or less for the same reason as described above.

The content of the titanium dioxide particles is in the range of 15% by mass or more and 45% by mass or less with respect to the total mass of the black ink composition for inkjet. When the content of the titanium dioxide particles is 15% by mass or more, a high refractive index (refractive index of 1.75 or more) can be easily obtained, which is also advantageous in terms of the stability of the black ink over time. Further, when the content of the titanium dioxide particles is 45% by mass or less, good stability over time can be easily obtained.
Among them, the content of titanium dioxide particles is more preferably in the range of 20% by mass or more and 35% by mass or less, and further preferably in the range of 23% by mass or more and 32% by mass or less for the same reason as described above.

-Basic dispersant-
The black ink of the present disclosure contains at least one kind of basic dispersant. When a basic dispersant is contained, the basic polar functional groups in the molecule easily act on the particle surface, and it is possible to maintain good dispersion stability of both titanium dioxide particles and carbon black particles in combination. Is.

The basic dispersant is a polymer having a basic polar functional group, and means a polymer having a weight average molecular weight of 1,000 or more. The weight average molecular weight is a value measured by GPC. The details of the measuring method will be described in detail in the section of photocurable resin described later.

Examples of the basic polar functional group in the basic dispersant include an amino group, an imino group, an amide group, an imide group, and a nitrogen-containing heterocyclic group. Of these, an amino group is preferable in terms of dispersibility.

The amine value of the basic dispersant can be selected in the range of 10 mgKOH / g or more and 150 mgKOH / g, and is preferably 10 mgKOH / g or more and 80 mgKOH / g or less.
When the amine value is 10 mgKOH / g or more, the dispersibility of both the carbon black particles and the titanium dioxide particles can be well maintained, and a high refractive index can be easily obtained. Further, when the amine value is 150 mgKOH / g or less, aggregation of carbon black particles and titanium dioxide particles can be suppressed to maintain good stability over time, and it becomes easy to secure a high refractive index.
Above all, as the amine value, a high refractive index can be obtained, and 10 mgKOH / g or more and 50 mgKOH / g or less are more preferable in terms of the stability of the black ink with time.

The amine value indicates the total amount of free bases and bases, and is expressed by the number of mg of potassium hydroxide equivalent to the hydrochloric acid required to neutralize 1 g of the sample.
The amine value is a value measured by a method conforming to JIS-K7237 (1995).

Examples of the basic dispersant include a salt of a long-chain polyaminoamide and a high-molecular-weight acid ester; a salt of a long-chain polyaminoamide and a polar acid ester; a polyester polyamine; a stearylamine acetate; an unsaturated carboxylic acid such as polyacrylic acid. (Partial) amine salt, (partial) ammonium salt or (partial) alkylamine salt of the (co) polymer; unsaturated polyamide; long-chain polyaminoamide phosphate; polyethyleneimine compounds [eg with polylower alkyleneimine] Amide which is a reaction product with a free carboxy group-containing polyester]; Polyallylamine-based compound [Example: Polyallylamine and polyester having a free carboxyl group, polyamide and polyesteramide (cocondensate of ester and amide) selected from three types Reaction products with at least one compound] and the like.
Among them, a compound having a polyester polyamine skeleton or a compound having a polyethyleneimine skeleton is preferable, and a compound having a polyethyleneimine skeleton is preferable.

As the basic dispersant, a commercially available product on the market may be used.
Examples of commercially available products are the Solsparse series manufactured by Nippon Louvre Resol Co., Ltd. [For example, trade name: Solsperse 24000 (amine value: 41.6 mgKOH / g), trade name: Solsperse 32000 (amine value: 31.2 mgKOH / g). ), Product name: Solsperse 35100 (amine value: 14 mgKOH / g), Product name: Solsperse 39000 (amine value: 35.7 mgKOH / g), Product name: Solsperse 71000 (amine value: 78 mgKOH / g), Product name: Solsperse J100, product name: Solsperse J200, etc.], DisperBYK series manufactured by Big Chemie Japan Co., Ltd. [Product name: DisperBYK-109 (amine value: 140 mgKOH / g), DisperBYK-162 (amine value: 13 mgKOH / g), product name: DisperBYK-163 (amine value: 10 mgKOH / g), product name: DISPERBYK-168 (amine value: 11 mgKOH / g), product name: DISPERBYK-2050 (amine value: 30.7 mgKOH / g), product name: DISPERBYK-2200 (30.7 mgKOH / g), trade name: DISPERBYK-2150 (amine value: 56.7 mgKOH / g), etc.], BYKJET series manufactured by Big Chemie Japan Co., Ltd. [brand name: BYKJET-9151 (amine value: 17.2 mgKOH) / G), Product name: BYKJET-9152 (amine value: 27.3 mgKOH / g), etc.], Ajishpar series manufactured by Ajinomoto Fine Techno Co., Ltd. [Product name: Ajisper PB821 (amine value: 11.2 mgKOH / g), Product name: Ajisper PB-822 (amine value: 18.2 mgKOH / g), Product name: Ajisper PB-881 (amine value: 17.4 mgKOH / g), Product name: Ajisper PB-824 (amine value: 17 mgKOH / g) ), Etc., EFKA PX4731 (amine value: 25 mgKOH / g) manufactured by BASF, etc. can be mentioned.

The content of the basic dispersant in the black ink composition for inkjet is preferably 3% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less with respect to the total mass of the ink.
When the content of the basic dispersant is 3% by mass or more, it is suitable for maintaining good dispersion stability of both titanium dioxide particles and carbon black particles when used in combination. Further, when the content of the basic dispersant is 20% by mass or less, it is advantageous in terms of ejection stability of the inkjet.

-Organic solvent with a boiling point of 120 ° C or higher-
The black ink of the present disclosure preferably contains an organic solvent having a boiling point of 120 ° C. or higher. When an organic solvent having a boiling point of 120 ° C. or higher is contained, the black ink of the present disclosure contains a relatively large amount of pigment particles, but it is easy to keep the ink viscosity low and it is easy to suppress an increase in the viscosity of the ink composition.

Examples of the organic solvent having a boiling point of 120 ° C. or higher include ethylene glycol monomethyl ether (boiling point: 124 ° C.), ethylene glycol monomethyl ether acetate (boiling point: 143 ° C.), propylene glycol methyl ether acetate (boiling point: 146 ° C.), and diethylene glycol dimethyl ether. (Boiling point: 162 ° C.), Diethylene glycol diethyl ether (DEGdEE) (Boiling point: 180 ° C.), Diethylene glycol ethylmethyl ether (Boiling point: 179 ° C.), Diethylene glycol monobutyl ether (Boiling point: 230 ° C.), Diethylene glycol dibutyl ether (Boiling point: 255 ° C.) , Glycol ether solvent such as triethylene glycol dimethyl ether (boiling point: 216 ° C.); benzoate such as methyl benzoate (boiling point: 199 ° C.), ethyl benzoate (boiling point: 213 ° C.), butyl benzoate (boiling point: 250 ° C.) Alkyl acid solvent; γ butyrolactone (boiling point: 204 ° C), 1,3-butanediol (boiling point: 208 ° C), cyclohexanone (boiling point: 156 ° C), terpineol (boiling point: 218 ° C), phenetol (boiling point: 170 ° C) , Isophorone (boiling point: 215 ° C.), 1,4-butanediol diacetate (boiling point: 232 ° C.), 1,3-butylene glycol diacetate (boiling point: 232 ° C.) and the like.
It is preferable to use two or more kinds of organic solvents in combination. By using two or more kinds of organic solvents in combination, the surface tension at the time of image formation and after drying can be changed, and the patterning property at the time of image formation can be improved.

When two or more organic solvents are used in combination, the boiling point of one of the two or more organic solvents having a boiling point of 120 ° C. or higher is set to BPa, and the other organic solvent is used from the viewpoint of controlling the drying rate. When the boiling point of the solvent is BPb, it is preferable to satisfy the relationship represented by the following formula.
120 ° C <BPa <BPb <250 ° C
Further, it is preferable to satisfy the relationship represented by the following formula.
150 ° C <BPa <BPb <230 ° C
The absolute value of the difference between BPa and BPb is preferably 10 ° C to 50 ° C.
The boiling point means the boiling point under 1 atm (101325 Pa).
The boiling point is a value measured by a boiling point meter, and can be measured using, for example, DosaTherm 300 manufactured by Titan Technologies Co., Ltd.

When two or more kinds of organic solvents are used in combination, the surface tension of one of the two or more kinds of organic solvents having a boiling point of 120 ° C. or higher is set to γa (from the viewpoint of increasing the surface tension as the drying progresses. When mN / m) is used and the surface tension of the other organic solvent is γb (mN / m), it is preferable to satisfy the relationship represented by the following formula.
γa <γb
Further, it is preferable to satisfy the relationship represented by the following formula.
γa <30mN / m <γb
The surface tension of the organic solvent is a value measured under the condition of a liquid temperature of 30 ° C. using a surface tension meter (DY-700, Kyowa Surface Chemistry Co., Ltd.).

As the organic solvent having a high surface tension (preferably, the surface tension exceeds 30 mN / m), the following solvents are preferable.

Among the organic solvents having high surface tension, at least one selected from γ-butyrolactone, methyl benzoate, 1,3 butanediol, ethyl benzoate, butyl benzoate, terpineol, and isophorone is preferable, and γ-butyrolactone and methyl benzoate are preferable. , 1,3 butanediol, terpineol, and at least one selected from isophorone are more preferred.

When two or more kinds of organic solvents are used, it is preferable to use two kinds of organic solvents in which the absolute value of the difference in surface tension is 5 mN / m to 20 mN / m.

When the black ink of the present disclosure contains an organic solvent, the content of the organic solvent is preferably 10% by mass or more and 55% by mass or less with respect to the total mass of the black ink composition for inkjet. 30% by mass to 50% by mass is more preferable, and 35% by mass to 45% by mass is further preferable.
When the content of the organic solvent is 10% by mass or more, it is easy to maintain the viscosity of the ink composition itself at a viscosity suitable for ejection by the inkjet method. Further, when the content of the organic solvent is 55% by mass or less, it is advantageous in that the stability of the black ink with time becomes better and the drying after ejection can be easily performed.

-Curable compound-
The black ink of the present disclosure preferably contains a curable compound in addition to the above components and is prepared to be curable. Since the black ink has curability, the adhesiveness to a non-absorbent base material (for example, glass or plastic) is improved, and the durability is excellent.

As the curable compound, at least one compound selected from a photocurable monomer and a photocurable resin is preferable.

(Photocurable monomer)
The photocurable monomer refers to a polymerizable monomer having a polymerizable group, and includes a monofunctional polymerizable monomer and a polyfunctional polymerizable monomer. A polymerizable group is a group having an ethylenically unsaturated double bond.

The black ink of the present disclosure preferably contains at least one monomer selected from a monofunctional polymerizable monomer and a polyfunctional polymerizable monomer, and is selected from a monofunctional polymerizable monomer and a bifunctional polymerizable monomer. It is more preferable to contain the above-mentioned monomer. The black ink of the present disclosure may also contain a trifunctional or higher functional polymerizable monomer.
Furthermore, the aspects of the black ink of the present disclosure are:
1) It may be an embodiment containing at least one of monofunctional polymerizable monomers and not containing bifunctional polymerizable monomers.
2) It may be an embodiment containing at least one bifunctional polymerizable monomer and not containing a monofunctional polymerizable monomer.
3) It may be an embodiment containing at least one kind of monofunctional polymerizable monomer and at least one kind of bifunctional polymerizable monomer.

The polymerizable monomer can have a function of maintaining a liquid state of the ink in addition to a function of imparting photocurability (that is, a property of being cured by light) to the black ink.

As a monofunctional polymerizable monomer,
N-vinyl compounds such as N-vinylcaprolactam and N-vinylpyrrolidone;
2-Phenoxyethyl acrylate (PEA), benzyl acrylate, cyclic trimethylolpropaneformal acrylate (CTFA), isobornyl acrylate (IBOA), tetrahydrofurfuryl acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, octyl acrylate, Decyl acrylate, tridecyl acrylate, isodecyl acrylate, lauryl acrylate, 3,3,5-trimethylcyclohexyl acrylate (TMCHA), dicyclopentenyl acrylate (DCPA), 4-t-butylcyclohexyl acrylate, cyclohexyl acrylate, caprolactone-modified acrylate, Monofunctional acrylate compounds such as hydroxyethyl acrylate, hydroxybutyl acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate, nonylphenoxy polyethylene glycol acrylate, nonylphenoxypolypolyglycol acrylate;
2-Phenoxyethyl methacrylate, benzyl methacrylate, isobornyl methacrylate (IBOA), tetrahydrofurfuryl methacrylate, 2- (2-ethoxyethoxy) ethyl methacrylate, octyl methacrylate, decyl methacrylate, tridecyl methacrylate, isodecyl methacrylate, lauryl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate (TMCHA), dicyclopentenyl methacrylate (DCPA), 4-t-butylcyclohexyl methacrylate, cyclohexyl methacrylate, caprolactone-modified methacrylate, hydroxyethyl methacrylate, hydroxybutyl methacrylate, polyethylene glycol methacrylate, polypropylene glycol Monofunctional methacrylate compounds such as methacrylate, nonylphenoxypolyethylene glycol methacrylate, nonylphenoxypolypropylene glycol methacrylate;
Monofunctional vinyl ether compounds such as normal propyl vinyl ether, isopropyl vinyl ether, normal butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, cyclohexanedimethanol monovinyl ether;
Acrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, acryloylmorpholin, N-isopropylacrylamide, N-hydroxyethylacrylamide, N-butylacrylamide, N-tert-butylacrylamide, N- (1,1-dimethyl) Monofunctional acrylamide compounds such as -3-oxobutyl) acrylamide, N-dodecylacrylamide, N- (butoxymethyl) acrylamide;
Monofunctional methacrylamide compounds such as methacrylamide, N-phenylmethacrylamide, N- (methoxymethyl) methacrylamide, N, N-dimethylmethacrylamide, N-tert-butylmethacrylamide, etc.;
And so on.

As a bifunctional polymerizable monomer,
Hexadiol diacrylate (HDDA), dipropylene glycol diacrylate (DPGDA), polyethylene glycol diacrylate, polypropylene glycol diacrylate, nonanediol diacrylate, decandiol diacrylate, neopentyl glycol diacrylate, polyethylene glycol modified bisphenol A diacrylate , Dioxane glycol diacrylate, cyclohexanedimethanol diacrylate, tricyclodecanedimethanol diacrylate and other bifunctional acrylate compounds; 2- (2-vinyloxyethoxy) ethyl acrylate (VEEA);
Bifunctional vinyl compounds such as 1,4-butanediol divinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether (DVE3);
Bifunctional methacrylate compounds such as hexanediol dimethacrylate, dipropylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, noneopentyl glycol dimethacrylate, polyethylene glycol-modified bisphenol A dimethacrylate;
Etc.

As photocurable monomers, in addition to the above-mentioned monofunctional polymerizable monomers and bifunctional polymerizable monomers, Shinzo Yamashita, "Crosslinking Agent Handbook", (1981 Taiseisha); Kiyomi Kato, " UV / EB Curing Handbook (Ingredients) "(1985, Polymer Publishing Association); Radtech Study Group," Applications and Markets of UV / EB Curing Technology ", p. 79, (1989, CMC); Eiichiro Takiyama Commercially available products described in the author, "Polyester Resin Handbook", (1988, Nikkan Kogyo Shimbun), etc., or monofunctional or bifunctional polymerizable monomers known in the industry can be used.

The weight average molecular weight of the photocurable monomer is preferably 100 or more and less than 1,000, more preferably 100 or more and 800 or less, and further preferably 150 or more and 700 or less.

The content of the photocurable monomer in the black ink of the present disclosure is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total mass of the black ink. The upper limit of the content of the polymerizable monomer is not particularly limited, and can be, for example, 95% by mass or less, 50% by mass or less, or 20% by mass or less.

(Photocurable resin)
The photocurable resin refers to a polymerizable resin that has a polymerizable group and is cured by a polymerization reaction with light, and is an oligomer having a polymerizable group (photocurable oligomer) and a polymer having a polymerizable group (photocurable). Sex polymer) is included. A polymerizable group is a group having an ethylenically unsaturated double bond.

Examples of the resin that is the base of the photocurable resin include acrylic resin, urethane resin, polyester resin, polyether resin, polycarbonate resin, epoxy resin, and polybutadiene resin. Among these, from the viewpoint of reducing curing shrinkage, a resin having both a hard segment and a soft segment and capable of relaxing stress during curing is preferable, and at least one resin selected from urethane resin, polyester resin, and epoxy resin in particular. Is more preferable.

As the polymerizable group contained in the photocurable resin, a group containing an ethylenic double bond is preferable, and a group containing at least one of a vinyl group and a 1-methylvinyl group is more preferable.
As the polymerizable group, a (meth) acryloyl group is particularly preferable from the viewpoint of polymerization reactivity and hardness of the film to be formed.

These polymerizable groups can be introduced into a resin (polymer or oligomer) by a polymer reaction or copolymerization.
For example, the reaction of a polymer (or oligomer) having a carboxy group in the side chain with glycidyl methacrylate, or the reaction of a polymer (or oligomer) having an epoxy group with an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid is used. This makes it possible to introduce a polymerizable group into the polymer (or oligomer). These groups may be used together.

As the photocurable resin, a commercially available product on the market may be used.
Examples of commercially available acrylic resins having a polymerizable group include (ACA) Z200M, (ACA) Z230AA, (ACA) Z251, (ACA) Z254F (above, Daicel Ornex Co., Ltd.), and Hitaroid 7975D (Hitachi Kasei). Co., Ltd.) and the like.

Examples of commercially available urethane resins having a polymerizable group include EBECRYL (registered trademark) 8402, EBECRYL (registered trademark) 8405, EBECRYL (registered trademark) 9270, EBECRYL (registered trademark) 8311, EBECRYL (registered trademark) 8701, KRM8667, KRM8528 (above, Daicel Ornex Co., Ltd.), CN964, CN9012, CN968, CN996, CN975, CN9782 (above, Sartmer), UV-6300B, UV-7600B, UV-7605B, UV-7620EA, UV- 7630B, UV-1700B (above, Nippon Synthetic Chemical Co., Ltd.), U-6HA, U-15HA, U-108A, U-200PA, UA-4200 (above, Shin Nakamura Chemical Industry Co., Ltd.), Tesslac 2300, Hitaroid 4863, Tesslac 2328, Tesslac 2350, Hitaroid 7902-1 (Hitachi Kasei Co., Ltd.), 8UA-017, 8UA-239, 8UA-239H, 8UA-140, 8UA-585H, 8UA-347H, 8UX-015A (As mentioned above, Taisei Fine Chemical Co., Ltd.) and the like.

Examples of commercially available polyester resins having a polymerizable group include CN294, CN2254, CN2260, CN2271E, CN2300, CN2301, CN2302, CN2303, CN2304 (hereinafter, Sartmer), EBECRYL (registered trademark) 436, and EBECRYL (registered trademark). ) 438, EBECRYL (registered trademark) 446, EBECRYL (registered trademark) 524, EBECRYL (registered trademark) 525, EBECRYL (registered trademark) 811, EBECRYL (registered trademark) 812 (above, Daicel Ornex Co., Ltd.), etc. Be done.
Examples of commercially available products of the polyether resin having a polymerizable group include Blemmer (registered trademark) ADE-400A, Blemmer (registered trademark) ADP-400 (above, NOF Corporation) and the like.
Examples of commercially available products of polycarbonate resins having a polymerizable group include polycarbonate diol diacrylate (Ube Industries, Ltd.) and the like.
Examples of commercially available epoxy resins having a polymerizable group include EBECRYL (registered trademark) 3708 (Dycel Ornex Co., Ltd.), CN120, CN120B60, CN120B80, CN120E50 (above, Sartmer), and Hitaroid 7851 (Hitachi Kasei (Hitachi Kasei). Co., Ltd.) and the like.
Examples of commercially available products of the polybutadiene resin having a polymerizable group include CN301, CN303, CN307 (above, Sartmer) and the like.

The weight average molecular weight of the photocurable resin is preferably 1000 or more and 100,000 or less, more preferably 1000 or more and 40,000 or less, and further preferably 1000 or more and 10000 or less, from the viewpoint of achieving both adhesion and dispersion stability. ..

The weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC).
For the measurement by gel permeation chromatography (GPC), HLC (registered trademark) -8020 GPC (Tosoh Co., Ltd.) was used as the measuring device, and TSKgel (registered trademark) Super Multipore HZ-H (4.6 mm ID ×) was used as the column. Use 3 bottles of 15 cm, Toso Co., Ltd., and use THF (tetrahydrofuran) as the eluent. The measurement conditions are as follows: the sample concentration is 0.45% by mass, the flow rate is 0.35 ml / min, the sample injection amount is 10 μl, and the measurement temperature is 40 ° C., using an RI detector.
The calibration curve is "Standard sample TSK standard, polystyrene": "F-40", "F-20", "F-4", "F-1", "A-5000", "A" of Tosoh Corporation. It is made from 8 samples of "-2500", "A-1000", and "n-propylbenzene".

When the ink composition of the present disclosure contains a photocurable resin, the content of the photocurable resin is preferably 5% by mass or more, more preferably 10% by mass or more. The upper limit of the content of the photocurable resin is not particularly limited, and can be, for example, 95% by mass or less, 50% by mass or less, or 20% by mass or less. ..

-Photopolymerization initiator-
The black ink of the present disclosure preferably further contains a photopolymerization initiator.
As the photopolymerization initiator, a known photopolymerization initiator that absorbs active energy rays to generate radicals that are polymerization initiators can be used.

Examples of the active energy ray include ultraviolet rays (UV), visible light, electron beam, and the like. Among them, ultraviolet rays are preferable from the viewpoint of versatility.

Examples of the photopolymerization initiator include (a) carbonyl compounds such as aromatic ketones, (b) acylphosphine oxide compounds, (c) aromatic onium salt compounds, (d) organic peroxides, and (e) thio compounds. It has (f) hexaarylbiimidazole compound, (g) ketooxime ester compound, (h) borate compound, (i) azinium compound, (j) metallocene compound, (k) active ester compound, and (l) carbon halogen bond. Examples thereof include compounds, (m) alkylamine compounds and the like.
As the photopolymerization initiator, the above compounds (a) to (m) may be used alone or in combination of two or more.

Preferred examples of the (a) carbonyl compound, (b) acylphosphine oxide compound, and (e) thio compound include "RADITION CURING IN POLYMER SCIENCE AND TECHNOLOGY", J. Mol. P. FOUASSIER, J. Mol. F. RABEK (1993), pp. Examples thereof include the compounds having a benzophenone skeleton or a thioxanthone skeleton described in 77 to 117.
More preferable examples include an α-thiobenzophenone compound described in Japanese Patent Publication No. 47-6416, a benzoin ether compound described in Japanese Patent Publication No. 47-3981, and an α-substituted benzoin compound described in Japanese Patent Publication No. 47-22326. Benzene derivative described in JP-A-47-23664, alloylphosphonic acid ester described in JP-A-57-30704, dialkoxybenzophenone described in JP-A-60-26483, JP-A-60-26403, JP-A. Benzene ethers described in 1987-81345, Japanese Patent Publication No. 1-34242, US Pat. No. 4,318,791 pamphlet, α-aminobenzophenones described in European Patent No. 0284561A1, JP-A-2-211452. P-di (dimethylaminobenzoyl) benzene described in JP-A, thio-substituted aromatic ketones described in JP-A-61-194062, acylphosphine sulfides described in JP-A-2-9597, JP-A-2-9596. Examples thereof include the acylphosphins described, the thioxanthones described in Japanese Patent Publication No. 63-61950, and the coumarins described in Japanese Patent Publication No. 59-42864.
Further, the polymerization initiators described in JP-A-2008-105379 and JP-A-2009-114290 are also preferable.

Among the photopolymerization initiators, (a) carbonyl compound or (b) acylphosphine oxide compound is more preferable, and specifically, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (for example, manufactured by BASF). IRGACURE® 819), 2- (dimethylamine) -1- (4-morpholinophenyl) -2-benzyl-1-butanone (eg, IRGACURE® 369 manufactured by BASF), 2-methyl -1- (4-Methylthiophenyl) -2-morpholinopropane-1-one (eg, IRGACURE® 907, manufactured by BASF), 1-hydroxy-cyclohexyl-phenyl-ketone (eg, manufactured by BASF). IRGACURE® 184), 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one (eg, IRGACURE® manufactured by BASF). 2959), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (for example, DAROCUR (registered trademark) TPO, LUCIRIN (registered trademark) TPO (both manufactured by BASF)) and the like.
Among these, (b) acylphosphine oxide compounds are preferable as the photopolymerization initiator, and monoacylphosphine oxide compounds (particularly preferably 2,4) are preferable from the viewpoint of improving sensitivity and compatibility with LED light. , 6-trimethylbenzoyl-diphenyl-phosphine oxide), or a bisacylphosphine oxide compound (particularly preferably, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide) is more preferable.

The photopolymerization initiator may be used alone or in combination of two or more.
When the black ink of the present disclosure contains a photopolymerization initiator, the content of the photopolymerization initiator is 0.5% by mass to 25.0% by mass with respect to the total mass of the black ink composition for inkjet. % Is preferable, 0.5% by mass to 20.0% by mass is more preferable, and 1.0% by mass to 15.0% by mass is further preferable.

-Other ingredients-
The black ink of the present disclosure may contain other components in addition to the above-mentioned components, if necessary.

(Colorant)
The black ink of the present disclosure may contain at least one colorant as long as the black color tone and high refractive index are not impaired.
The colorant can be arbitrarily selected from known colorants such as pigments and dyes other than the above-mentioned carbon black and titanium dioxide.
However, since the black ink of the present disclosure has a composition using carbon black particles and titanium dioxide particles from the viewpoint of ensuring a high refractive index while having a black color tone, the content of the colorant is high. Less is preferable. In particular, the content of the dye is preferably less than 10% by mass, more preferably less than 1% by mass, still more preferably less than 0.1% by mass, based on the total mass of the black ink. A dye content of less than 10% by mass indicates that the composition does not contain a large amount of dye, and a dye content of less than 0.1% by mass indicates that the composition contains a large amount of dye. Indicates that it is not.

The pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include known organic pigments and inorganic pigments. Further, resin particles dyed with a dye, a commercially available pigment dispersion or a surface-treated pigment (for example, a pigment dispersed in water, a liquid compound, an insoluble resin, etc. as a dispersion medium, a resin, a pigment derivative, etc.) The surface of the pigment is treated with the above, etc.).
Examples of the organic pigment and the inorganic pigment include yellow pigment, red pigment, magenta pigment, blue pigment, cyan pigment, green pigment, orange pigment, purple pigment, brown pigment, black pigment, white pigment and the like.
When a pigment is used as the colorant, a pigment dispersant may be used as needed when preparing the pigment particles.
For colorants such as pigments and pigment dispersants, known documents such as paragraphs 0152 to 0158 of JP2011-225884A and paragraphs 0132 to 0149 of JP2009-209352 can be appropriately referred to.

When the black ink of the present disclosure contains a colorant (excluding dyes), the content of the colorant may be, for example, 0.1% by mass to 20% by mass with respect to the total mass of the black ink. it can.
It is also preferable that the black ink of the present disclosure is used as an ink that does not substantially contain a colorant. Here, "substantially free" means that the content of the colorant is less than 0.1% by mass with respect to the total mass of the black ink.

(binder)
When the black ink of the present disclosure does not contain a curable compound, a binder may be contained.
As the binder, known binder polymers such as polyester resin, polyurethane resin, vinyl resin, acrylic resin, and rubber resin can be used. Among them, acrylic resin or polyester resin is preferable, and methyl methacrylate alone is inactive. Polymers and / or copolymers are more preferred.
As the binder, a commercially available product on the market may be used. For example, a polymethylmethacrylate manufactured by Aldrich (molecular weight 10,000, catalog number 81497; molecular weight 20,000, catalog number 81489; molecular weight 50,000, catalog number 81501) may be used. ), Methyl methacrylate / n-butyl methacrylate copolymer (mass ratio 85/15, molecular weight 75,000; Catalog No. 474029), etc .; Lucite International
ELVACITE 2013 (methyl methacrylate / n-butyl methacrylate copolymer, mass ratio 36/64, molecular weight 37,000), 2021, 2614, 4025, 4026, 4028, etc .; Rohm and Haas Paraloid DM55, B
66 etc.; BR113, 115 etc. manufactured by Mitsubishi Rayon Co., Ltd. can be mentioned.
The weight average molecular weight (Mw) of the binder polymer is preferably 1,000 or more, more preferably 1,000 to 1,000,000, and even more preferably 5,000 to 200,000. , 8,000-100,000 is particularly preferable.
The weight average molecular weight is a value measured by GPC, and the measuring method is the same as that of the photocurable resin described above.
The glass transition temperature (Tg) of the binder polymer is preferably 50 to 120 ° C, more preferably 60 to 100 ° C. Tg is a value measured by differential scanning calorimetry (DSC).
The binder polymer may be used alone or in combination of two or more.

(Polymerization inhibitor)
The black ink of the present disclosure may contain a polymerization inhibitor.
Polymerization inhibitors include p-methoxyphenols, quinones (eg, hydroquinone, benzoquinone, methoxybenzoquinone, etc.), phenothiazines, catechols, alkylphenols (eg, dibutylhydroxytoluene (BHT), etc.), alkylbisphenols, dimethyldithiocarbamine. Zinc acid, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionic acid esters, mercaptobenzimidazole, phosphites, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO), Examples thereof include 2,2,6,6-tetramethyl-4-hydroxypiperidin-1-oxyl (TEMPOL), cuperon Al, and tris (N-nitroso-N-phenylhydroxylamine) aluminum salts.
Among them, at least one selected from p-methoxyphenols, catechols, quinones, alkylphenols, TEMPO, TEMPOL, cuperon Al, and tris (N-nitroso-N-phenylhydroxylamine) aluminum salts is preferable.
When the black ink of the present disclosure contains a polymerization inhibitor, the content of the polymerization inhibitor is preferably 0.01% by mass to 2.0% by mass, preferably 0.02, based on the total mass of the black ink. More preferably, it is by mass% to 1.0% by mass.

(Sensitizer)
The black ink of the present disclosure may additionally contain a sensitizer.
A sensitizer is a substance that absorbs a specific active energy ray and becomes an electron-excited state. The sensitizer in the electron-excited state comes into contact with the photopolymerization initiator and causes actions such as electron transfer, energy transfer, and heat generation. This promotes chemical changes in the photopolymerization initiator, that is, decomposition, radicals, acid or base production, and the like.

Examples of the sensitizer include benzophenone (BP), thioxanthone, isopropylthioxanthone (ITX), ethyl 4- (dimethylamino) benzoate (EDB), anthraquinone, 3-acylcoumarin derivative, terphenyl, styrylketone, 3-. (Aloylmethylene) Thiazoline, ginseng quinone, eosin, rhodamine, erythrosin and the like can be mentioned.
Further, as the sensitizer, a compound represented by the general formula (i) described in JP-A-2010-24276 and a compound represented by the general formula (I) described in JP-A-6-107718. Can also be suitably used.
Among them, the sensitizer is selected from thioxanthone, isopropylthioxanthone, ethyl 4- (dimethylamino) benzoate, and benzophenone from the viewpoint of compatibility with light emitting diode (LED) light and reactivity with a photopolymerization initiator. At least one type is preferable.
When the black ink of the present disclosure contains a sensitizer, the content of the sensitizer is preferably 0.5% by mass to 10% by mass.

(Surfactant)
The black ink of the present disclosure may contain a surfactant.
Examples of the surfactant include the surfactants described in JP-A-62-173436 and JP-A-62-183457. For example, anionic surfactants such as dialkyl sulfosuccinate, alkylnaphthalene sulfonate, fatty acid salt, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, acetylene glycol, polyoxyethylene / polyoxypropylene block copolymer, modified Examples thereof include nonionic surfactants such as siloxanes such as polydimethylsiloxane, cationic surfactants such as alkylamine salts and quaternary ammonium salts, and betaine-based surfactants such as carbobetaine and sulfobetaine.
When the black ink of the present disclosure contains a surfactant, the content of the surfactant is preferably 0.01% by mass to 5.0% by mass with respect to the total mass of the black ink.

(water)
The black ink of the present disclosure may contain a small amount of water.
The black ink of the present disclosure is preferably a non-water-based ink that does not substantially contain water. Specifically, the content of water with respect to the total mass of the black ink of the present disclosure is preferably 3% by mass or less, more preferably 2% by mass or less, and further preferably 1% by mass or less.

(Other ingredients)
The black ink of the present disclosure may contain other components other than the above.
Examples of other components include ultraviolet absorbers, co-sensitizers, antioxidants, anti-fading agents, conductive salts and the like. For other components, publicly known documents such as JP-A-2011-225884 and JP-A-2009-209352 can be appropriately referred to.

~ Physical properties of black ink composition for inkjet ~
(viscosity)
The viscosity of the black ink composition for inkjet of the present disclosure at 25 ° C. is preferably 10 mPa · s to 50 mPa · s, more preferably 10 mPa · s to 30 mPa · s, and 10 mPa · s to 25 mPa · s. It is more preferably s. The viscosity of the ink can be adjusted, for example, by adjusting the composition ratio of each component contained. When the viscosity of the ink is in the above-mentioned preferable range, the ejection stability at the time of ejection by the inkjet method can be further improved.
The viscosity is a value measured using a viscometer (VISCOMETER RE-85L, Toki Sangyo Co., Ltd.) for an ink composition whose temperature has been adjusted to 25 ° C.

(surface tension)
The surface tension of the black ink composition for inkjet of the present disclosure at 30 ° C. is preferably 20 mN / m to 30 mN / m, and more preferably 23 mN / m to 28 mN / m. When forming a film on various substrates such as polyolefin, PET, coated paper, and uncoated paper, 30 mN / m or less is preferable in terms of wettability, and 20 mN / m or more is preferable in terms of image bleeding suppression and permeability. preferable.
The surface tension is a value measured using a surface tension meter (DY-700, Kyowa Surface Chemistry Co., Ltd.) for an ink composition whose temperature has been adjusted to 30 ° C.

<Image formation method>
The black ink of the present disclosure can be suitably used for forming a film.
The image formation can be performed by a method using an inkjet method, and preferably, a step of applying the above-mentioned black ink composition for inkjet (black ink) of the present disclosure to a substrate by an inkjet method (hereinafter, "" It can be performed by a method (the image forming method of the present disclosure) having a "giving step".
The image forming method of the present disclosure further includes a step of irradiating the black ink applied on the base material with active energy rays (hereinafter, also referred to as “irradiation step”) after the application step. Is preferable. By using an ink containing a curable compound as the black ink and providing an irradiation step after the applying step, it is possible to form a film having better adhesion to the substrate.
The details of the base material will be described in detail in the section of light-shielding film described later.

(Granting process)
In the applying step, the black ink of the present disclosure is applied onto the base material by an inkjet method.
The black ink can be applied by the inkjet method using a known inkjet recording device. The inkjet recording device is not particularly limited, and a known inkjet recording device can be arbitrarily selected and used.

Examples of the inkjet recording device include a device including an ink supply system, a temperature sensor, and a heating means.
The ink supply system preferably includes, for example, a source tank containing the ink composition, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo type inkjet head. The piezo type inkjet head preferably has multi-size dots of 1 pl to 100 pl (more preferably 8 pl to 30 pl), preferably 320 dpi (dot per inch) × 320 dpi to 4000 dpi × 4000 dpi (more preferably 400 dpi × 400 dpi to 1600 dpi ×). It is preferable that the device can be driven so that it can be discharged at a resolution of 1600 dpi, more preferably 720 dpi × 720 dpi to 1600 dpi × 1600 dpi).
In addition, dpi represents the number of dots per 2.54 cm (1 inch).

(Irradiation process)
In the irradiation step, the black ink applied on the base material is irradiated with active energy rays.
When the black ink is irradiated with active energy rays, the polymerization reaction of the curable compound in the black ink proceeds. As a result, the film (for example, an image) can be cured and fixed, and the film strength can be improved.

Examples of the active energy rays to be irradiated in the irradiation step include ultraviolet rays (UV), visible rays, electron beams, and the like, and among them, ultraviolet rays are preferable from the viewpoint of versatility.
The peak wavelength of the active energy ray is preferably 200 nm to 405 nm, more preferably 220 nm to 390 nm, and even more preferably 220 nm to 385 nm.

Illuminance on the irradiated surface of the active energy ray is irradiated, for ^example, preferably ^{10mW / cm 2 ~2000mW / cm 2} , 20mW / cm 2 ~1000mW / cm 2 is more preferable.

Examples of the light source for irradiating the active energy ray include a mercury lamp, a metal halide lamp, an ultraviolet (UV) fluorescent lamp, a gas laser, a solid-state laser and the like. In addition, the replacement of the illustrated light source with a semiconductor ultraviolet light emitting device is useful in terms of industry and environment.
Among semiconductor ultraviolet light emitting devices, LEDs (Light Emitting Diodes) and LDs (Laser Diodes) are expected as light sources because of their small size, long life, high efficiency, and low cost.
Among the above, as the light source, a metal halide lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp, an LED, or a bluish purple laser is preferable. Among them, when the sensitizer and the photopolymerization initiator are used in combination, an ultra-high pressure mercury lamp capable of irradiating light having a wavelength of 365 nm, 405 nm or 436 nm, a high-pressure mercury lamp capable of irradiating light having a wavelength of 365 nm, 405 nm or 436 nm, Alternatively, an LED capable of irradiating light having a wavelength of 355 nm, 365 nm, 385 nm, 395 nm or 405 nm is more preferable, and an LED capable of irradiating light having a wavelength of 355 nm, 365 nm, 385 nm is most preferable.

In the irradiation step, the irradiation time of the active energy rays on the ink composition applied on the substrate can be, for example, 0.01 seconds to 120 seconds, preferably 0.1 seconds to 90 seconds.
As the irradiation conditions and the basic irradiation method, the irradiation conditions and the irradiation method disclosed in Japanese Patent Application Laid-Open No. 60-132767 can be similarly applied.
As the activation energy ray irradiation method, specifically, a method in which light sources are provided on both sides of the head unit including the ink composition ejection device and the head unit and the light source are scanned by a so-called shuttle method, or a method without driving is provided. A method of irradiating active energy rays with a light source is preferable.
The irradiation of the active energy rays is preferably performed after a certain period of time (for example, 0.01 seconds to 120 seconds, preferably 0.01 seconds to 60 seconds) after the ink composition is landed and heat-dried. ..

(Heat drying process)
At the time of image formation, if necessary, a heat drying step may be further provided after the applying step, or after the applying step and before the irradiation step.
In the heat-drying step, the black ink applied on the base material in the application step is dried.

Drying can be performed using heating means.
The heating means is not particularly limited, and for example, a heat drum, a hot air blower, an infrared lamp, a heat oven, a heat plate, or the like can be used.
The heating temperature during drying is preferably 40 ° C. or higher, more preferably 40 ° C. to 150 ° C., and even more preferably 40 ° C. to 80 ° C.
The heating time can be appropriately set in consideration of the composition of the black ink and the formation speed of the film (image).

<Shading film>
The light-shielding film of the present disclosure is a cured product of the black ink composition for an inkjet of the present disclosure described above. Therefore, it has a blackish color tone and a high refractive index.

The light-shielding film of the present disclosure is a film having a high refractive index, and the refractive index is preferably 1.75 or more, and more preferably 1.80 or more.
The refractive index is a value measured by ellipsometry at a wavelength of 590 nm, and can be measured using a high-speed spectroscopic ellipsometer M-2000 (JA Woolam Japan Co., Ltd.).

The light-shielding film of the present disclosure contains at least carbon black particles, titanium dioxide particles, and a basic dispersant, and can contain a curable compound and other components, if necessary. The details of the components such as the carbon black particles, the titanium dioxide particles and the basic dispersant, and the curable compound and other components are as described above, and the description thereof will be omitted here.
The colorant contained in the light-shielding film can be arbitrarily selected from known coloring materials such as pigments and dyes other than carbon black and titanium dioxide.
As described above, the light-shielding film of the present disclosure uses the above-mentioned black ink and has a composition using carbon black particles and titanium dioxide particles, so that the content of the colorant is preferably small. .. In particular, the content of the dye is preferably less than 10% by mass, more preferably less than 1% by mass, and even more preferably less than 0.1% by mass with respect to the total mass of the light-shielding film. A dye content of less than 10% by mass indicates that the composition does not contain a large amount of dye, and a dye content of less than 0.1% by mass indicates that the composition contains a large amount of dye. Indicates that it is not.

The thickness of the light-shielding film can be in the range of 0.5 μm to 20 μm, preferably in the range of 0.5 μm to 10 μm, and more preferably in the range of 0.5 μm to 5 μm.

The light-shielding film of the present disclosure can be used not only for blocking light, but also for absorbing light, providing a decorative function, and the like.
Above all, the light-shielding film of the present disclosure is preferably used for an optical member. Details of the optical member will be described later.

<Optical member>
The optical member of the present disclosure includes a base material and the above-mentioned light-shielding film of the present disclosure.
Since the optical member of the present disclosure includes a light-shielding film having a high refractive index formed by using the black ink composition for inkjet of the present disclosure described above, the difference in refractive index between the base material and the light-shielding film is small. It is possible to effectively absorb the reflected light when the incident light is internally reflected in the base material.
Since the details of the light-shielding film are as described above, the description thereof will be omitted.

-Base material-
The base material is not particularly limited, and either a non-absorbent base material that does not absorb ink or an absorbent base material that absorbs ink can be used.
"Non-absorbent" means water absorption (mass%, 24 hr) in ASTM D570 of the ASTM test method.
.. ) Is less than 0.2.

Examples of the non-absorbent base material include a glass base material, a resin (plastic) base material [eg, a polyvinyl chloride (PVC) base material, a polystyrene (PS) base material, a polypropylene (PC) base material, and a polyester base material (for example, Polyethylene terephthalate (PET), polyethylene naphthalate), polyolefin base material (for example, polypropylene (PP)), acrylic resin base material, etc.] and the like.
Examples of the absorbent base material include paper and non-woven fabric.

The optical member of the present disclosure preferably uses a glass base material or a resin base material as the base material, and has a light-shielding film on the outer peripheral surface when the thickness direction of the glass base material or the resin base material is taken as an axis. be able to.
Preferred specific examples of the optical member include a lens, a prism, optical glass and the like.
When the optical member is, for example, a lens, for example, a glass base material or a resin base material is used, and a light-shielding film is provided on the outer peripheral surface of concentric circles about the thickness direction of the glass base material or the resin base material, that is, the incident direction of light. doing. In this case, when the light obliquely incident into the lens hits the outer peripheral surface of the lens (that is, the interface between the lens and the light-shielding film) before passing through the lens, it is absorbed by the light-shielding film and suppresses internal reflection at the interface. can do. As a result, it is possible to suppress the occurrence of flare or ghost due to the incident of light not related to the image.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded. Unless otherwise specified, "parts" are based on mass.

(Examples 1 to 17, Comparative Examples 1 to 7)
-Preparation of ink composition-
Each component shown in Tables 1 and 2 below is mixed and subjected to dispersion treatment under the following conditions using a bead mill NPM (manufactured by Simmal Enterprises) and a circulation type piping and charging tank. 5000 g of each ink composition having the composition shown in 2 was prepared.

<Dispersion condition>
Bead diameter: φ0.05 mm
Bead filling rate: 60% by volume
Mill peripheral speed: 10 m / sec Amount of mixed liquid to be dispersed: 5000 g
Circulation flow rate (pump supply amount): 30 kg / hour
Treatment liquid temperature: 25 ° C to 30 ° C
Cooling water: Tap water Treatment time: 30 passes

-Film formation-
Using each ink composition prepared as described above, each ink was dropped onto a glass substrate (Corning 1737 (manufactured by Corning), thickness 0.7 mm), and a spin coating method (2000 rpm (revolutions per minute)) was performed. , 60 seconds). The coating film is dried in a heating furnace at 70 ° C. for 30 minutes, and the dried coating film is further exposed to ultraviolet light (wavelength 365 nm) at 1200 mJ / cm using an ultraviolet light emitting diode NC4U134 (manufactured by Nichia Chemical Industries, Ltd.). ^The coating film was cured by irradiating with an exposure energy amount of ² (that is, an integrated amount of ultraviolet light).
In this way, a light-shielding film having a thickness of 1.0 μm after curing was formed.

-Evaluation-
The following measurements and evaluations were performed on the ink composition and the light-shielding film prepared as described above. The measurement and evaluation results are shown in Tables 1 to 3. In addition, "γ" and "bm" described in the column of the organic solvent of Table 1 represent "surface tension" and "boiling point", respectively.

(1) Refractive index of light-shielding film The refractive index of the light-shielding film was measured at a wavelength of 590 nm using a high-speed spectroscopic ellipsometer M-2000 (JA Woolam Japan Co., Ltd.), and the following values were used based on the measured values. It was evaluated according to the evaluation criteria.
<Evaluation criteria>
AA: The refractive index is 1.85 or more.
A: The refractive index is 1.80 or more and less than 1.85.
B: The refractive index is 1.75 or more and less than 1.80.
C: The refractive index is less than 1.75.

(2) Light-shielding property of light-shielding film For the glass substrate on which the light-shielding film is formed, a desktop transmission densitometer 361T (manufactured by X-Rite) is used, and the optical density at transmission (transmission OD; "OD" is Optical Density. Omitted) was measured. Based on the measurement results, evaluation was performed according to the following evaluation criteria.
The larger the measured value, the better the light-shielding property.
<Evaluation criteria>
AA: The transmission OD is 0.4 or more.
A: The transmission OD is 0.3 or more and less than 0.4.
B: The transmission OD is 0.1 or more and less than 0.3.
C: The transmission OD is less than 0.1.

(3) Stability of ink composition over time Each ink composition prepared as described above was allowed to stand in an environment of a temperature of 60 ° C. for 7 days, and the average particle size fluctuated before and after the standing (particle size fluctuation; %) Was measured. The particle variation was calculated from the following formula. Then, using the value of particle size fluctuation as an index, the stability over time was evaluated according to the following evaluation criteria.
Particle size fluctuation (%) = (average particle size after standing) / (average particle size before standing) x 100
The average particle size was measured by a particle size analyzer (FPAR, manufactured by Otsuka Electronics Co., Ltd.). At the time of measurement, diethylene glycol diethyl ether was used as a diluting solvent for adjusting the concentration.
<Evaluation criteria>
AA: Particle variation is less than 10%.
A: Particle variation is 10% or more and less than 15%.
B: Particle variation is 15% or more and less than 20%.
C: Particle variation is 20% or more and less than 25%.

(4) Patterning property The operation of forming the coating film is changed to the operation of drawing 10 line patterns, and the same operation as the above "-film formation-" is performed, and the target line width is 1 mm. Ten light-shielding patterns (that is, line patterns cured by ultraviolet light irradiation) were formed.
Here, the line pattern was formed by applying ink to a glass substrate by an inkjet method using an inkjet printer DMP-3000 manufactured by FUJIFILM Corporation. At this time, the dot density was set to 1200 dpi × 1200 dpi, and the ink ejection amount per drop ejected from the inkjet head was set to 10 pL (picolitre).

For 10 shading patterns, the line width of 10 points (that is, 100 points in total) was measured for each shading pattern, and the average line width was calculated as the arithmetic mean value of the obtained measured value group, and the obtained average was obtained. Based on the line width, the average fluctuation width of the line width was calculated by the following formula.
Average fluctuation width of line width (%) = (average line width-1) x 100

Based on the obtained average fluctuation range, the patterning property was evaluated according to the following evaluation criteria, and the evaluation results are shown in Table 3.
In the following evaluation criteria, the rank with the best patterning property is "A".
<Evaluation criteria>
A: The average fluctuation range is less than 10%.
B: The average fluctuation range is 10% or more and less than 18%.
C: The average fluctuation range is 18% or more.
D: The line width cannot be measured due to poor ejection or poor line pattern drawing.

Details of each component shown in Tables 1 and 2 are as follows.
-Carbon black particles-
Special black 250: Made by Orion Engineered Carbons (Furness Black; Average primary particle size: 56 nm, DBP absorption amount: 48 ml / 100 g)
-Titania particles-
TTO-55A: Made by Ishihara Sangyo Co., Ltd. (Rutile type; average primary particle size: 50 nm, surface treatment: Al (OH) ₃ )
R-550: manufactured by Ishihara Sangyo Co., Ltd. (rutile type; average primary particle size: 240 nm, surface treatment: Al, Si)
-Zirconia particles-
TECNAPOW-ZNO: Made by TECNAN (Average primary particle size: 15 nm)

-Dispersant-
EFKA PX4731: Made by BASF (basic dispersant, amine value: 25 mgKOH / g; compound having a polyethyleneimine skeleton)
DisperBYK-168: manufactured by Big Chemie Japan Co., Ltd. (basic dispersant, amine value: 11 mgKOH / g)
solspec71000: manufactured by Nippon Lubrizol Co., Ltd. (basic dispersant, amine value: 78 mgKOH / g)
DisperBYK-109: manufactured by Big Chemie Japan Co., Ltd. (basic dispersant amine value: 140 mgKOH / g)
solspec 39000: manufactured by Nippon Lubrizol Co., Ltd. (basic dispersant, amine value: 35.7 mgKOH / g)
solspec 36000: manufactured by Nippon Lubrizol Co., Ltd. (acid dispersant)
DisperBYK-111: Made by Big Chemie Japan Co., Ltd. (acid dispersant)

-Curable compound-
UV-1700B: Urethane acrylate (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; photocurable oligomer)
PEA: 2-phenoxyethyl acrylate (monofunctional photocurable monomer)
DPGDA: Dipropylene glycol diacrylate (bifunctional photocurable monomer)
-Photopolymerization initiator-
IRG819: IRGACURE® 819 (BASF; bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide))
IRG2959: IRGACURE® 2959 (BASF; 2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone)
-Polymerization inhibitor-
MEHQ: p-methoxyphenol (manufactured by Tokyo Chemical Industry Co., Ltd.)

-Organic solvent-
-DEGdEE: Diethylene glycol diethyl ether (boiling point 180 ° C., surface tension 25.0 mN / m)

As shown in Tables 1 and 2, a specific amount of titanium dioxide particles is contained, and the carbon black particles and the titanium dioxide particles are contained in a ratio higher than that of the carbon black particles, and further basic dispersion is performed. In the examples in which the composition was selectively used with the agent, the light-shielding property was good and a high refractive index was obtained. In addition, the dispersion stability over time was also good, and the suitability for inkjet was excellent.
In particular, a higher refractive index was obtained in Example 1 and the like in which the particle size of the titanium dioxide particles was 100 μm or less as compared with Example 7 in which the particle size of the titanium dioxide particles was large, and the stability over time was also excellent.
Similarly, as compared with Example 10 in which the amine value of the basic dispersant is high, in Example 1 and the like using the basic dispersant having an amine value of 80 mgKOH / g or less, a higher refractive index can be obtained and with time. It was excellent in terms of stability.
Furthermore, from the comparison between Example 2 and Example 12, it can be seen that the mass ratio of the content of titanium dioxide particles to the content of carbon black particles is preferably 13 or less.
Further, as shown in Table 3, in Examples 13 to 16 in which a plurality of types of organic solvents were used in combination within a certain range, better results were obtained in terms of patterning property as compared with Example 1.

On the other hand, in the comparative example, the effect of improving the refractive index is inferior to that of the example, or the stability of the ink composition with time is inferior. It was difficult to achieve compatibility with the refractive index.

The black ink composition for inkjet of the present disclosure is suitable for applications requiring a black color tone having a high refractive index, and can also be applied to decorative applications in that it has a high refractive index. Specific examples include light-shielding films for optical elements (eg, lenses, prisms, optical glass members) used in optical equipment such as cameras, binoculars, microscopes, and semiconductor exposure equipment, and black-based materials with surface gloss. It is suitable for use as a color-tone decorative film.
Further, the light-shielding film and the optical member of the present disclosure can be widely used in applications requiring light-shielding.

The disclosures of Japanese application Japanese Patent Application No. 2018-059958 filed on March 27, 2018 and Japanese application Japanese Patent Application No. 2019-023498 filed on February 13, 2019 are incorporated herein by reference in their entirety.
All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims (16)

Containing carbon black particles, titanium dioxide particles, and a basic dispersant,
The content of the titanium dioxide particles is 15% by mass or more and 45% by mass or less with respect to the total mass of the composition.
A black ink composition for an inkjet in which the mass ratio of the content of the titanium dioxide particles to the content of the carbon black particles is 2.0 or more and 15.0 or less. The black ink composition for an inkjet according to claim 1, wherein the basic dispersant has an amine value of 10 mgKOH / g or more and 80 mgKOH / g or less. The black ink composition for an inkjet according to claim 1 or 2, wherein the titanium dioxide particles have an average primary particle diameter of 10 nm or more and 100 nm or less. The black ink composition for an inkjet according to any one of claims 1 to 3, wherein the content of the carbon black particles is 1% by mass or more and 6% by mass or less with respect to the total mass of the composition. The black ink composition for an inkjet according to any one of claims 1 to 4, further comprising an organic solvent having a boiling point of 120 ° C. or higher. The black ink composition for an inkjet according to claim 5, wherein the content of the organic solvent is 10% by mass or more and 55% by mass or less with respect to the total mass of the composition. It contains at least two kinds of organic solvents having a boiling point of 120 ° C. or higher,
When the boiling point of one organic solvent is BPa and the boiling point of the other organic solvent is BPb among the organic solvents having a boiling point of 120 ° C. or higher, the relationship of 120 ° C. <BPa <BPb <250 ° C. is satisfied. ,
And,
Among the organic solvents having a boiling point of 120 ° C. or higher, the surface tension of one organic solvent in mN / m is defined as γa, and the surface tension of the other organic solvent in mN / m is defined as γa. When γb is set, the relationship of γa <γb is satisfied.
The black ink composition for an inkjet according to claim 5 or 6. The black ink composition for an inkjet according to claim 7, wherein the γa and the γb satisfy the relationship represented by γa <30 mN / m <γb. The black ink composition for an inkjet according to any one of claims 1 to 8, further comprising at least one curable compound selected from a photocurable monomer and a photocurable resin. A light-shielding film which is a cured product of the black ink composition for inkjet according to any one of claims 1 to 9. The light-shielding film according to claim 10, which has a refractive index of 1.75 or more. The light-shielding film according to claim 10 or 11, wherein the content of the dye is less than 10% by mass. The light-shielding film according to any one of claims 10 to 12, which is used for an optical member. With the base material
The light-shielding film according to any one of claims 10 to 13.
An optical member equipped with. The base material is a glass base material or a resin base material,
The optical member according to claim 14, further comprising the light-shielding film on the outer peripheral surface of the glass base material or the resin base material in the thickness direction. An image forming method comprising a step of applying the black ink composition for inkjet according to any one of claims 1 to 9 onto a substrate by an inkjet method.