WO2024009703A1 - Pigment, and ink composition or coating composition using same - Google Patents

Abstract

Provided are: a pigment of uniform shape, the pigment having little variation in shape or size; and an ink composition or a coating composition that uses the pigment.　The pigment has two or more rotational symmetries and when observed from the direction in which the projected area of the pigment is at maximum, the coefficient of variation of the maximum length Lmax within the projection plane is 10% or lower. The relationship between D50, D10, and D90 preferably satisfies the relationship in formula (I).　Formula (I): (D90−D10)/D50≤1.0

Description

Pigment and ink composition or coating composition using the same

The present invention relates to, for example, pigments used in inks and paints, and ink compositions or paint compositions using the pigments.

In recent years, there has been an increase in the diversification of small lots of printed matter, and inkjet printing methods, which are on-demand prints, are attracting attention as an alternative to conventional offset printing methods and gravure printing methods. Inkjet printing methods are simpler than conventional printing methods, and have advantages such as economic efficiency and energy saving. Inkjet printing is a printing method in which minute droplets of ink ejected from an inkjet head land on a recording medium and are fixed through drying, curing, penetration, etc. to form dots, and images are formed when many of these dots come together. It's a method.

In addition, images having glittering properties such as metallic luster may be expressed on substrates (recording media) or objects such as printed matter coated with colored ink compositions on part or all of their surfaces. be. Methods for imparting such glitter include applying ink using metal powder made from brass, aluminum fine particles, etc. by silk screen printing or gravure printing, foil stamping printing using metal foil, and metal foil printing. A thermal transfer method using , etc. has been used.

In recent years, in addition to the above-mentioned method of forming a glittering coating film, there have been many applications of inkjet printing methods, such as glittering decorative printing using an inkjet method. This is mainly carried out using an inkjet printer or the like.

For example, Patent Document 1 describes a glitter pigment used in an ink composition discharged by an inkjet method, which is obtained by crushing a thin film formed by vapor deposition or sputtering, and an ink using the same. Compositions are disclosed.

Further, Patent Document 2 describes a glitter pigment used in an ink composition discharged by an inkjet method, which is obtained by crushing particles formed by an atomization method, and an ink composition using the same. things are disclosed.

JP2011-052041A Special Publication No. 2011-508030

The pigments of Patent Documents 1 and 2 both require a pulverization step, as is clear from their manufacturing methods. Since the grinding process relies on physical impact, it necessarily has a very wide particle size distribution. The width of the particle size distribution is measured, for example, as a volume-based cumulative particle diameter such as D10, D50, D90, etc.

When pigments such as glitter pigments are used in compositions such as inks and paints, they have irregular and distorted shapes and extremely wide particle size distributions due to the grinding process. For example, there is a problem that the stability of pigments such as dispersibility and sedimentation is insufficient. However, as mentioned above, it has been common for conventional glitter pigments to have a very wide particle size distribution, so it was considered inevitable to avoid this problem. Attempts have been made to narrow the particle size distribution through filtering, etc., but this is still insufficient, as it is limited by the pulverization process. In addition, as a result, ink that does not contribute to the required glitter or functionality, or that inhibits glitter or functionality, contains many particles of unintended sizes and shapes, or has poor printing suitability. and coating compositions, which may result in insufficient glitter and functionality in printed materials and coated materials.

When the above-mentioned pigment is applied to an ink composition for an inkjet method, variations in shape and size also affect performance as an inkjet ink, such as ejection properties.

An object of the present invention is to provide a pigment having a uniform shape with little variation in shape or size, and an ink composition or coating composition using the pigment.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that pigments of uniform shape and size can be obtained by a manufacturing method that does not use a pulverization process, thereby solving the above-mentioned problems. , we have completed the present invention. Specifically, the present invention provides the following.

(1) A pigment with rotational symmetry of two or more times, in which the coefficient of variation of the maximum length Lmax in the projection plane is 10% or less when observed from the direction in which the projected area of the pigment is maximum.

(2) The volume-based cumulative 50% particle diameter (D50) is 0.1 μm or more and 10 μm or less,
The relationship between the volume-based cumulative 10% particle diameter (D10) (μm), the volume-based cumulative 50% particle diameter (D50) (μm), and the volume-based cumulative 90% particle diameter (D90) (μm) is as follows. The pigment according to (1), which satisfies the relationship of formula (I).
(D90-D10)/D50≦1.0...(I)

(3) The pigment according to (1) or (2), wherein the pigment is a glittering pigment.

(4) The pigment according to any one of (1) to (3), which is used in an ink composition discharged by an inkjet method.

(5) From (1), the pigment has a first surface and a second surface that are parallel to each other, and a planar view from the first surface side and the second surface side is a polygonal shape having corners. The pigment according to any one of (4).

(6) The pigment according to any one of (1) to (5), wherein the maximum length Lmax is 0.5 μm or more and 10 μm or less.

(7) When the pigment is plate-shaped, the pigment according to any one of (1) to (6) has a thickness, which is the distance between the first surface and the second surface, of 10 nm or more and 250 nm or less. .

(8) After forming a deposited film by depositing a substance constituting the pigment on a mold in which a plurality of uneven shapes corresponding to the shape of the pigment are formed, (1) peeling off the deposited film from the mold. The method for producing a pigment according to any one of (7) to (7).

(9) Any one of (1) to (7), including plating a substance constituting the pigment on a mold in which a plurality of uneven shapes corresponding to the shape of the pigment are formed, and then peeling off the plating film from the mold. A method for producing the pigment described in Crab.

(10) An ink composition or coating composition containing the pigment according to any one of (1) to (7).

(11) A coated product in which an ink composition or a coating composition containing the pigment according to any one of (1) to (7) is applied to the surface of a base material.

(12) A method for producing a printed matter, which comprises applying an ink composition containing a pigment according to any one of (1) to (7) onto the surface of a substrate by an inkjet method.

(13) A recording method in which an ink composition containing the pigment according to any one of (1) to (7) is applied to the surface of a substrate by an inkjet method.

According to the present invention, it is possible to provide a pigment that can suppress deterioration of stability such as dispersibility and sedimentation, and an ink composition and a coating composition using the pigment.

3 is a SEM image of the pigment of Example 2. 3 is a SEM image of the pigment of Example 4. 3 is a SEM image of the pigment of Example 9. 3 is a SEM image of the pigment of Example 10. 3 is a SEM image of the pigment of Comparative Example 1. 3 is a SEM image of the pigment of Comparative Example 4. 3 is a SEM image of the pigment of Comparative Example 5. FIG. 2 is a schematic diagram of a shaping mold.

Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and may be implemented with appropriate changes within the scope of the purpose of the present invention. be able to.

<1. Pigment>
[Type of pigment]
Pigments include, in addition to colored pigments (coloring materials), pigments containing metals and metal oxides, bright pigments, conductive pigments, insulating pigments, pigments that absorb specific wavelengths, and pigments that reflect specific wavelengths. Examples include materials having optical properties and functionality other than for decorative purposes, but are not particularly limited. Examples of bright pigments include those containing pearl pigments and metal-containing bright pigments.

Pearl pigments include metal oxides and metal compounds such as mica, fish scale foil, bismuth acid chloride, silicon dioxide, and titanium oxide, and laminates of metal oxides such as titanium oxide/silicon dioxide/titanium oxide. Examples include pigments having pearlescent luster or interference luster.

The metal contained in the metal-containing pigment includes at least one of simple metals such as aluminum, silver, gold, nickel, chromium, tin, zinc, indium, titanium, copper, and iron; metal compounds; alloys and mixtures thereof; Examples include oxides of these metals and inorganic oxides doped with metals. As the metal-containing pigment, it is preferable to use one containing aluminum, nickel, indium, silver, copper, chromium, or iron. By using a metal-containing glitter pigment containing any one of aluminum, nickel, indium, silver, copper, chromium, and iron, it is possible to impart a more suitable metallic luster to the object. In particular, aluminum is preferred because it is cheaper and easier to process than other metals. The ink composition according to this embodiment can provide an effect of imparting a more suitable metallic gloss to the object, while also providing excellent ejection properties of the ink composition.

[Maximum length of pigment]
In the present invention, the coefficient of variation of the maximum length Lmax on the projection plane when observed from the direction in which the projected area of the pigment is maximum is 10% or less.

Since the coefficient of variation of the maximum length Lmax is 10% or less, it has a uniform shape and size, and has an extremely narrow particle size distribution, which reduces dispersibility and sedimentation when used as an ink composition or coating composition. The present inventors have found that it is possible to suppress a decrease in stability such as shelf life and shelf life. Moreover, when used as an ink composition for inkjet, inkjet ejection stability and printing unevenness are significantly improved.

If the pigments contained in the ink have the same shape and size, filterability is significantly improved. For example, with conventional plate-shaped bright pigments, the plane is easily distorted (not smooth) and irregular, and the periphery in plan view is uneven, so it gets caught around the filtration holes, and the pigments tend to stick to each other. The pigment may aggregate around the filtration pores and block the filtration pores, resulting in a large amount of pigment not passing through the filtration pores. Furthermore, since the particles are amorphous and uneven, particles tend to aggregate with each other, resulting in a large amount of pigment not passing through the filtration holes. On the other hand, since the pigment of the present invention has a uniform shape, uniform size, and uniform plane, the filterability is significantly improved. Note that this is supported by the results of Examples described later.

Particularly in an inkjet head with a fine structure, such behavior greatly affects ejection performance. Droplet formation may become unstable due to uneven distribution of pigments of different sizes within the head or uneven transmission of pressure for ejecting ink. If the liquid permeability of the filter in the inkjet head deteriorates, ejection failure may occur, such as non-ejection, bending, or scattering, resulting in poor ejection performance, and the ejected ink droplet size and pigment concentration in the ink droplets may become uneven or uneven. It may occur.

As mentioned above, conventional bright pigments are manufactured by vapor deposition or atomization methods, and in this case, as is clear from the manufacturing method, it is necessary to adjust the particle size through a pulverization process. There is. Since this pulverization process is based on physical impact such as a ball mill or ultrasonic waves, the particles inevitably have a predetermined particle size distribution and an amorphous shape. In other words, after going through the crushing process, it is impossible to have the same shape and size.

The present invention differs from conventional pigments in that it uses a mold for forming the pigment, which is formed by nanoimprinting, which will be described later. As a result, it is possible to basically obtain particles of the same shape and size depending on the mold, which is unprecedented.

Here, the maximum length Lmax on the projection plane when observed from the direction in which the projected area of the pigment is maximum is, for example, when the pigment is plate-shaped (also expressed as flat, fine plate, scale-like, etc.) , means the maximum length in plan view measured with a SEM image, and if the plan view is square, it means the length of the diagonal line. If it is columnar or conical, it means the maximum length observed in a SEM (scanning electron microscope) image.

Further, the coefficient of variation (Cv value) in the present invention is calculated from the arithmetic mean value of the maximum length Lmax and its standard deviation obtained by measuring 100 pigments, as coefficient of variation = standard deviation ÷ arithmetic mean value. be. The coefficient of variation is preferably 10% or less, more preferably 9% or less, even more preferably 8% or less.

[Shape of pigment]
In the present invention, the shape of the pigment has two or more rotational symmetries. When a pigment has rotational symmetry, it means that it has a shape that is symmetrical about the rotation axis, and it means that it has n rotation axes (n is an integer of 2 or more), and includes a circle. Thereby, when used as an ink composition or a coating composition, it is possible to suppress deterioration of stability such as dispersibility and sedimentation property and storage stability. Furthermore, when used as an inkjet ink composition, the inkjet ejection stability is significantly improved.

For example, in the case of a plate, if the plane view (xy plane in FIG. 8) is an ellipse or a rectangle, two times ( An equilateral triangle has three-fold (120 degrees) rotational symmetry, and a square has four-fold (90 degrees) rotational symmetry. In addition, in the case of a columnar shape, if it is a rectangular parallelepiped, it has two-fold (180 degrees) rotational symmetry with respect to the rotation axis that passes through the center of gravity and is perpendicular to the opposing parallel first and second surfaces. If the shape is a regular triangular prism, it has three-fold (120 degrees) rotational symmetry, and if it is a regular quadrangular prism, it has four-fold (90 degrees) rotational symmetry. In addition, in the case of a cone shape, with respect to the rotation axis passing through the center of gravity and perpendicular to the base, if it is a regular triangular pyramid shape, it has three times (120 degrees) rotational symmetry, and if it is a regular square pyramid shape, it has four times rotational symmetry. (90 degrees) rotational symmetry.

The specific shape of the pigment having the above-mentioned rotational symmetry may be plate-shaped (also expressed as flat, fine plate-shaped, scale-shaped, etc.), columnar, or cone-shaped. You can.

In the case of a plate, it has a first surface and a second surface that are parallel to each other, and when viewed from the first surface side or the second surface side, it has a polygonal shape such as a triangle, square, pentagon, hexagon, etc. The shape may be a circle or an ellipse and similar shapes thereof. Further, when the pigment of the present invention has a corner, the corner is not limited to a strict corner, but may be a corner formed by a curved surface.

Note that "parallel" in the present invention includes not only complete parallelism but also substantial parallelism within a certain error range, that is, substantially parallelism. Moreover, "planar view seen from the first surface side or the second surface side" means an observed image when a plate-shaped pigment is observed with an SEM.

In the case of a plate shape, the length of one side of the first surface and the second surface is preferably 0.5 μm or more and 10.0 μm or less. Further, the thickness is preferably 10 nm or more and 250 nm or less.

In the case of a columnar shape, the length of one side of the first and second surfaces is preferably 0.5 μm or more and 10.0 μm or less. Further, the thickness is preferably more than 250 nm and not more than 10.0 μm.

In the case of a conical shape, the length of one side is preferably 0.5 μm or more and 10.0 μm or less. Further, the thickness (cone height) is preferably 10 nm or more and 10.0 μm or less.

In addition, regardless of whether it is plate-shaped, columnar, or conical, the maximum length of one side is preferably set so that the diagonal of the projection plane is 500 nm or more and 10 μm or less.

[Pigment volume-based cumulative particle diameter]
The width of the particle size distribution of the pigment is also measured as a volume-based cumulative particle diameter such as D10, D50, D90, etc., for example.

In the present invention, the volume-based cumulative 10% particle diameter (D10) (μm), the volume-based cumulative 50% particle diameter (D50) (μm), and the volume-based cumulative 90% particle diameter (D90) (μm) of the pigment are preferably used. μm) satisfies the relationship of the following formula (I), and the volume-based cumulative 50% particle diameter (D50) is 0.5 μm or more and 10 μm or less.
(D90-D10)/D50≦1.0...(I)

In addition, the volume-based cumulative 10% particle diameter (D10) in this specification means the particle diameter (μm) that is the cumulative 10% calculated from the small diameter side in the volume-based cumulative particle size distribution. 50% particle diameter (D50) (μm) means the cumulative 50% particle diameter (μm) calculated from the small diameter side, and the volume-based cumulative 90% particle diameter (D90) is calculated from the small diameter side. It means the particle diameter (μm) that is cumulatively 90%. Further, the volume-based cumulative 50% particle diameter (D50) may also be referred to as "volume average particle diameter," "average particle diameter," or "median diameter." Hereinafter, each particle size may be simply written as "D10", "D50", and "D90". Moreover, in this specification, "A≦B" means that A is equivalent to B, or that A is smaller than B (B is larger than A).

The D10, D50, D90 and thickness of the pigment can be measured using a particle size distribution measuring device or the like. Specifically, it can be measured with "FPIA-3000S" manufactured by Sysmex Corporation, "SALD 7500nano" laser diffraction particle size distribution analyzer manufactured by Shimadzu Corporation, "Accusizer" manufactured by Nippon Entegris LLC, etc. Alternatively, the measurement can be performed using a microscope, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or the like. Specifically, it can be measured with S-4800 manufactured by Hitachi High Technologies, 1510 manufactured by Hitachi High Technologies, Phenon Prox manufactured by Jusco International, etc.

(D90-D10)/D50 in formula (I) is 1.0 or less, preferably 0.9 or less, and more preferably 0.8 or less. Thereby, when used as an ink composition or a coating composition, it is possible to suppress deterioration of stability such as dispersibility and sedimentation property and storage stability. Furthermore, when used as an inkjet ink composition, the inkjet ejection stability is significantly improved.

(D90-D10)/D50 in formula (I) is preferably greater than zero, more preferably 0.1 or more.

(D90-D10) in formula (I) is preferably 6.0 or less, more preferably 5.0 or less.

(D90-D10) in formula (I) is preferably 0.1 or more, more preferably 0.2 or more.

D90 is preferably 10.0 μm or less, more preferably 9.0 μm or less, and even more preferably 8.0 μm or less.

D90 is preferably 0.5 μm or more, more preferably 0.6 μm or more, and even more preferably 0.7 μm or more.

D50 is 10.0 μm or less, preferably 9.0 μm or less, more preferably 8.0 μm or less, and even more preferably 6.0 μm or less.

D50 is 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.4 μm or more, and even more preferably 0.5 μm or more.

D10 is preferably 7.0 μm or less, more preferably 6.0 μm or less, and even more preferably 5.0 μm or less.

D10 is 0.1 μm or more, preferably 0.2 μm or more, and more preferably 0.3 μm or more.

[Pigment manufacturing method]
The pigments of the present invention do not undergo a pulverization process after being formed in a large area as in the past, but each pigment is formed using a mold and then peeled off from the mold, resulting in a uniform shape and uniform size. pigments can be obtained directly. Specifically, the following two methods can be exemplified.

The first manufacturing method is a method in which a substance constituting the pigment is vapor-deposited onto a mold in which a plurality of uneven shapes corresponding to the shape of the pigment are formed to form a vapor-deposited film, and then the vapor-deposited film is peeled from the mold. It is.

Specifically, a mold is formed in which a plurality of uneven shapes corresponding to the pigment shape are formed, and the uneven shape of this mold is shaped into a film or a film coated with resin to obtain a shaping mold. A process of obtaining a shaping mold by the so-called nanoimprint method, a vapor deposition process of forming a thin film along the uneven shape with a predetermined thickness by vapor deposition or sputtering on this mold, and peeling off the thin film from the shaping mold. The method further includes, if necessary, a purification step for removing unnecessary size particles by centrifugation or filtration. Note that the mold is not limited to a shaping mold, and may be formed by photolithography, which will be described later. Further, in order to smooth the vapor deposition surface, a dry etching step may be provided after vapor deposition as necessary, and a desired pigment may be produced by repeating the vapor deposition and dry etching steps.

FIG. 8 is a conceptual perspective view showing an example of the above-mentioned shaping mold. In this shaping mold 100, on the surface of a shaping base material 150, square irregularities are alternately arranged in a staggered pattern when viewed from above. Each of the uneven portions is composed of a square top flat portion 110 constituting the first surface, a square bottom flat portion 120 constituting the second surface, and a vertical side wall 130. Here, in the vapor deposition process, by performing vapor deposition perpendicularly to the xy plane in FIG. By performing this, a square-shaped pigment corresponding to concave and convex planes can be obtained. Note that the peeling process may be physical peeling, chemical peeling, a combination thereof, etc., and is not particularly limited, and may be appropriately adjusted depending on the properties of the deposited film and the pigment.

The uniformity of the deposited film can be obtained by measuring the variation in thickness using an AFM (also called an atomic force microscope or a scanning probe microscope), and according to the present invention, the uniformity of the deposited film when n=10 or more is measured. The standard deviation can be 10% or less. The standard deviation of the thickness is preferably 10% or less, more preferably 5% or less, and even more preferably 2% or less.

Note that the vapor deposition film may also be formed on the uneven side wall 130, but due to the characteristics of the vapor deposition method, it is easier to vapor deposit on the top and bottom surfaces than in the vertical direction. The side wall 130 is thinner than the top flat part 110 and the bottom flat part 120, so by applying an appropriate shearing force such as brushing to the xy plane (physical peeling), the vapor deposition film on the side wall 130 can be easily removed. It is possible to separate the pigment from the deposited film (pigment) on the top flat part 110 and the bottom flat part 120 and prevent the pigments from connecting with each other. Further, by transferring only the vapor deposited film onto the adhesive surface of the adhesive film, the connection between the side wall 130, the upper flat part 110, and the bottom flat part 120 can be severed by the impact. Thereafter, a tabular pigment can be obtained by removing the adhesive layer by, for example, dissolving the adhesive layer. In order to remove the vapor deposited film on the side wall 130, a purification process such as centrifugation or classification may preferably be performed to remove undersized particles originating from the side wall. Further, a separate purification process such as a filtration process for removing non-imprinted portions and upper-sized fragments may be provided. By this method, a uniform pigment with a uniform shape corresponding to an uneven shape can be obtained, and is particularly suitable for obtaining a plate-shaped pigment.

Note that if the vapor deposition surface is tilted to perform so-called oblique vapor deposition, the thickness may become uneven on the inclined surface or shadows may be formed, making it impossible to completely vapor deposit at the desired location. As a result, a pigment having rotational symmetry cannot be obtained, and the yield of the pigment also decreases. Furthermore, since oblique vapor deposition is often performed in a batch manner for small areas, it is difficult to increase productivity.

The second manufacturing method involves plating a substance constituting the pigment onto a mold in which a plurality of uneven shapes corresponding to the shape of the pigment are formed, and then peeling off the plating film from the mold. Note that plating is used to include the so-called electroforming method.

Specifically, there is a mold forming process in which a mold is formed with a plurality of uneven shapes corresponding to the shape of the pigment using photolithography, and a film formation process in which a plating film is formed by plating (electroforming) only on the concave portions of this mold. step, and a peeling step of peeling off the coating from the mold, and further includes a filtration step of removing unnecessary sizes by filtering, if necessary. Note that the mold is not limited to photolithography, and may be formed using the above-mentioned shaping mold.

By this method, a uniform pigment with a uniform shape corresponding to an uneven shape can be obtained, and it is particularly suitable for obtaining a pigment having a thickness such as a columnar shape or a conical shape.

A protective layer may be formed (coated) on the surface of the pigment. Preferably, the protective layer is a non-metallic protective layer. Examples of the non-metallic protective layer include a layer made of a hydrophobic compound such as a resin or a fatty acid compound. For example, fatty acids, fatty acid esters, aromatic carboxylic acids, aromatic carboxylic esters, phosphoric acid esters, silicon-containing compounds, fluorine-containing compounds, polymers and oligomers containing these, polyester resins, acrylic resins, epoxy resins, urethane resins. , cellulose ester resin, etc. Particularly when the bright pigment contains aluminum, the protective layer is preferably made of a hydrophobic compound. Examples of the hydrophobic compound include compounds having a structure such as an alkyl group having 4 or more carbon atoms, an aromatic group, an alicyclic group, a trifluoro group, etc., and which do not dissolve in water, and the above-mentioned resins. By forming a protective layer on the surface of the pigment, oxidation of the pigment can be suppressed, resulting in an ink composition with high storage stability.

<2. Ink composition or coating composition>
The ink composition or coating composition (hereinafter also simply referred to as composition) of the present invention contains the above pigment. The ink composition or coating composition may be solvent-based (non-aqueous), water-based, or active energy ray-curable, and is not particularly limited.

In the case of an ink composition, it is suitably used as an ink composition discharged by an inkjet method. When this ink composition is ejected onto an object by an inkjet method, the ink composition is applied to the surface of the object, and when the pigment is a glitter pigment, the object has a metallic or pearlescent appearance. Glossiness (glitter) can be imparted. In the case of materials that have functions other than decoration, such as conductive pigments, insulating pigments, pigments that absorb specific wavelengths, and pigments that reflect specific wavelengths, those functions can be imparted. Note that in this specification, the term "substrate" may be the surface of the recording medium itself, or may be one in which a colored ink composition or a primer is applied to a part or the entire surface of the recording medium, and there are no particular limitations. It is not something that will be done. It is also used not only for inkjet, but also for ink (paint) used in dispensers, ink (paint) used in coaters, sprayers, etc., ink used in offset and gravure printing, toner, etc. can. The pigment of the present invention is a uniformly shaped particle that can be obtained without the need for a pulverization process, so there is no distortion or deterioration of structure and functionality caused by general physical pulverization, and it has excellent dispersibility. It is easy to add to ink compositions and coating compositions.

The composition may be an aqueous composition, an active energy ray-curable composition that is cured by irradiation with active energy rays, or a non-aqueous composition. A non-aqueous ink composition is an ink composition that does not contain water. As used herein, "contains no water" means that the ink composition is manufactured without intentionally containing water, for example, water vapor contained in the atmosphere or contained in additives. Water that is contained due to reasons not intended by the manufacturer, such as water contained in the product, is not considered.

The content of the pigment contained in the composition is not particularly limited, but the lower limit of the content of the pigment is preferably 0.3% by mass or more, and 0.5% by mass based on the total amount of the ink composition. The content is more preferably at least 1.0% by mass, and even more preferably at least 1.0% by mass. As a result, when the pigment is a glittering pigment, it becomes possible to impart a more suitable metallic luster to the object. The upper limit of the pigment content is not particularly limited, but in the case of inkjet inks, it is preferably 5.0% by mass or less, and preferably 4.0% by mass or less based on the total amount of the ink composition. The content is more preferably 3.0% by mass or less. Since the pigment of the present invention has extremely high uniformity, good glitter can be obtained even with a small content, and dischargeability can be maintained even with a large content, so it is possible to obtain good functionality. It has the characteristic that it can be done.

In addition, in the case of paints for painting, dispensers, and spray paints other than inkjet inks, the content of pigment in the paint composition is preferably 40% by mass or less, and preferably 35% by mass or less. The content is more preferably 30% by mass or less. In the case of ink compositions used in coater application, silk screen printing, gravure printing, etc., the content of the ink composition is preferably 30% by mass or less, more preferably 25% by mass or less, and 20% by mass or less. It is more preferable that In the case of an ink composition used in offset printing or the like, it is preferably at most 25% by mass, more preferably at most 20% by mass, and even more preferably at most 15% by mass. The lower limit is preferably 1.0% by mass or more, more preferably 3.0% by mass or more, and even more preferably 5.0% by mass or more.

(Method for producing composition)
The method for producing the composition of the present invention involves adding a bright pigment and other necessary components such as an organic solvent, water, a polymerizable compound, a dispersant, a surfactant, a resin, a polymerization initiator, and a pH adjuster. A composition can be produced by mixing the following.

For example, in the case of a non-aqueous composition, it can be prepared by adding an organic solvent, a bright pigment, and if necessary a resin, a surfactant, etc.; After adding a resin, a surfactant, and other ingredients as necessary, a method of preparing a glitter pigment, a resin, a surfactant, and other ingredients as necessary are added to an organic solvent. Examples include a method of preparing by adding a pigment.
For example, in the case of an aqueous composition, it can be prepared by adding water, an organic solvent, a glitter pigment, and if necessary a resin, an additive, etc., or it can be prepared by adding a glitter pigment and a surface treatment agent to an organic solvent. After that, water, a resin, a surfactant, and other components are added as necessary.
For example, in the case of active energy ray-curable compositions, a method of preparing a composition by adding a polymerizable compound, a polymerization initiator, a glittering pigment, an oligomer, a polymer, an additive, etc. as necessary, or a method of preparing a composition by adding a glittering compound to an organic solvent, Examples include a method of preparing by adding a pigment and a dispersant, and then adding a polymerizable compound, a polymerization initiator, and other components as necessary. A polymerizable compound is a compound having an ethylenically unsaturated double bond that is polymerized by irradiation with active energy rays. Active energy rays include ultraviolet rays (UV), electron beams (EB), and the like.

Next, printed matter (coated matter) obtained using the composition of the present invention will be explained.

<3. Printed matter (coated material)>
A coated product such as a printed matter obtained using the composition according to the above embodiment or a coating film obtained using the coating composition includes a base material (recording medium) and a base material (recording medium). When the above-mentioned composition is applied to the surface and the pigment is a glittering pigment, metallic luster can be imparted to the object.

[Base material (recording medium)]
The substrate (recording medium) is not particularly limited, and may be a non-absorbent substrate such as a resin substrate, metal plate, or glass, or an absorbent substrate such as paper or cloth. A variety of base materials can be used, including a base material with a surface coating such as a base material provided with a layer.

Non-absorbent base materials include polyester resins (polyethylene terephthalate, polyethylene naphthalate), polypropylene synthetic paper, polyolefin resins (polypropylene resins, polyethylene resins, etc.), acrylic resins, polystyrene resins, and polycarbonate resins. Examples include resin base materials such as ABS resin, vinyl chloride resin, and polyimide resin, metal, metal foil coated paper, glass, synthetic rubber, and natural rubber.

Examples of the absorbent substrate include cardboard, medium-quality paper, high-quality paper, synthetic paper, cotton, synthetic fabric, silk, hemp, fabric, nonwoven fabric, and leather.

Examples of the surface-coated base material include coated paper, art paper, cast paper, lightweight coated paper, lightly coated paper, and the like. Moreover, in the case of an ink composition, various base materials having an ink absorbing layer can also be used.

[others]
A primer may be applied to the substrate. Primers are applied to the surface of a substrate (recording medium) to improve the fixing properties of colored ink compositions containing coloring materials (dyes and pigments) and compositions containing glitter pigments, and to suppress bleeding. It has a function to improve image quality.

For example, when printing a glitter ink composition, a colored ink composition may be used together. A colored ink composition is an ink composition containing a coloring material (dye/pigment) that is different from a glittering pigment and is used in ordinary ink compositions. Furthermore, printing with a colored ink composition may be performed before or after printing with the glitter ink composition. This colored ink composition may be an active energy ray-curable ink composition or a non-aqueous ink composition that contains a coloring material and does not contain water. It may also be an aqueous ink composition. Alternatively, a plurality of ink compositions (for example, a plurality of ink compositions including yellow ink, magenta ink, cyan ink, and black ink) may be used. Note that this colored ink composition may contain a resin.

Furthermore, the method of applying this colored ink composition is not particularly limited. Examples include a spray method, a coater method, an inkjet method, a gravure method, a flexo method, and the like. Among these, it is preferable to discharge (coat) by an inkjet method. If the inkjet method is used, it is easy to discharge (coat) to any location on the base material or to discharge (coat) the entire surface of the base material.

The coloring material of the colored ink composition is not particularly limited, and may be dye-based or pigment-based, but pigment-based ink with good water resistance, light resistance, etc. Preference is given to using compositions. Pigments that can be used in the colored ink composition are not particularly limited. Examples include organic pigments or inorganic pigments used in conventional ink compositions. These may be used alone or in combination of two or more. Specific organic pigments include, for example, insoluble azo pigments, soluble azo pigments, derivatives from dyes, phthalocyanine organic pigments, quinacridone organic pigments, perylene organic pigments, perinone organic pigments, dioxazine organic pigments, and nickel azo pigments. Pigments, isoindolinone organic pigments, pyranthrone organic pigments, thioindigo organic pigments, condensed azo organic pigments, benzimidazolone organic pigments, quinophthalone organic pigments, isoindoline organic pigments, quinacridone solid solution pigments, perylene pigments Examples of inorganic pigments such as organic solid solution pigments such as solid solution pigments include titanium oxide and zinc oxide, and examples of other pigments include carbon black and the like. Pigments that can be used in the ink composition may be a combination of multiple organic pigments or inorganic pigments, or a combination of a pigment dispersion dispersed in a water-soluble solvent using a pigment dispersant and a self-dispersed pigment. There may be.

[Overcoat agent]
An overcoat agent may be applied to the surface of the printed matter. The overcoat agent is formed on the uppermost surface of the printed matter (for example, the surface of the colored ink composition) and has the function of improving the durability of the printed matter.

The overcoat agent may be an active energy ray-curable ink composition, a nonaqueous ink composition that does not contain water, or an aqueous ink composition that contains water. The overcoat agent is, for example, a colored ink composition containing the above-mentioned coloring material (dye/pigment), which has a resin component or a polymerizable compound as its main component, and excludes or reduces the amount of the coloring material so that the color is not visible. An ink composition prepared as described above may also be used. Adhesion with the colored ink composition or glitter ink composition can be improved by using an overcoat agent having the same composition as the colored ink composition or glitter ink composition. Further, the overcoat agent may be, for example, a conventionally known overcoat agent.

Any method may be used to apply the overcoat agent to the surface of the printed matter, such as spray application, application using cloth or sponge, dispenser, brush application, coater, gravure printing, flexographic printing, Any method such as silk screen printing, inkjet printing, or thermal transfer method may be used.

<4. Recording method＞
As a recording method for recording on the surface of a base material (recording medium) using the composition according to the above embodiment, any printing method or coating method can be applied, such as offset, gravure, silk screen, toner, spray, dispenser, etc. It is applicable to either method. Among these, when used in the inkjet method, the ejection stability is high and it is well applicable.

The inkjet recording device can be applied to any inkjet recording device such as a piezo type, a thermal type, an electrostatic type, etc. From the viewpoint of versatility and high definition, the piezo method is preferable.

The inkjet recording apparatus may be equipped with a drying mechanism such as a heater or a feeder in order to dry the ink composition (for example, glitter ink composition) discharged by the inkjet method.

The glitter pigment contained in an ink composition (for example, a glitter ink composition) has a particle diameter controlled within a predetermined range, so it has high inkjet ejection stability, and recording using this ink composition By this method it is possible to obtain printed matter with a desired metallic tone.

<5. Manufacturing method of printed matter (coated material)>
A recording method in which a composition (for example, a glitter ink composition) according to the above embodiment is discharged onto the surface of a base material can also be defined as a method for producing a printed matter and a printed matter. For example, it is possible to obtain printed matter with a desired metallic tone by a method of manufacturing printed matter using a glitter ink composition.

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these descriptions in any way.

1. Preparation and evaluation of glitter pigment <Example 1>
A shaping mold having a square uneven shape in a plan view as shown in FIG. A thin aluminum film having a predetermined average film thickness was formed on the mold (in the table, it is labeled "NIP-vapor deposition"; the same applies to Examples 2 to 8). After that, it goes through a peeling process that applies physical shear using brush rollers, centrifugation to remove particles with a specific gravity that is lighter than the target particles, and a purification process that includes filtration to remove dust and some upper-sized fragments. , as shown in Table 1, the average length of the major axis (diagonal of the square) is 0.7 μm, the coefficient of variation (Cv value) of the major axis length is 6%, and the thickness is 0.05 μm. A bright pigment (A-1) of Example 1 was obtained.

<Example 2>
Same as Example 1 except that the shaping mold and vapor deposition conditions were changed, and the average value of the major axis length was 1.4 μm, the coefficient of variation (Cv value) of the major axis length was 7%, and the thickness was 0.03 μm. A plate-shaped glitter pigment (A-2) of Example 2 was obtained. FIG. 1 is a SEM image of the glitter pigment of Example 2.

<Example 3>
Same as Example 1 except that the shaping mold and vapor deposition conditions were changed, and the average value of the major axis length was 2.8 μm, the coefficient of variation (Cv value) of the major axis length was 3%, and the thickness was 0.10 μm. A plate-shaped glitter pigment (A-3) of Example 3 was obtained.

<Example 4>
Same as Example 1 except that the shaping mold and vapor deposition conditions were changed, and the average value of the major axis length was 7.1 μm, the coefficient of variation (Cv value) of the major axis length was 3%, and the thickness was 0.25 μm. A plate-shaped glitter pigment (A-4) of Example 4 was obtained. FIG. 2 is a SEM image of the glitter pigment of Example 4.

<Example 5>
The vapor deposition material was changed to chromium (Cr), the shaping type and vapor deposition conditions were changed, and the average value of the major axis length was 2.3 μm, the coefficient of variation (Cv value) of the major axis length was 3%, and the thickness was 0. A plate-shaped bright pigment (A-5) of Example 5 was obtained in the same manner as in Example 1 except that the thickness was 10 μm.

<Example 6>
A shaping mold with a quadrangular pyramidal uneven shape was created using the nanoimprint method, the vapor deposition material was changed to titanium oxide (TiO ₂ ), the shaping mold and the vapor deposition conditions were changed, and the major axis length (diagonal length of the bottom surface) was changed to titanium oxide (TiO 2 ). A square pyramid shape was prepared in the same manner as in Example 1, except that the average value of the diameter) was 2.8 μm, the coefficient of variation of the major axis length (Cv value) was 7%, and the thickness (cone height) was 0.50 μm. A bright pigment (A-6) of Example 6 was obtained.

<Example 7>
The vapor deposition material was changed to a three-layer structure of titanium oxide (TiO ₂ )-silicon oxide (SiO ₂ )-titanium oxide (TiO ₂ ), and the shaping type and vapor deposition conditions were changed so that the average value of the major axis length was 2. The bright pearl pigment of Example 7 (A-7) was prepared in the same manner as in Example 1 except that the coefficient of variation (Cv value) of the major axis length was 3% and the thickness was 0.20 μm. I got it.

<Example 8>
A shaping mold having a concavo-convex shape in the shape of a truncated pyramid (with tapered sides) was created using the nanoimprint method, the deposition material was changed to silver (Ag), the shaping mold and deposition conditions were changed, and the major axis length was adjusted. Same as Example 1 except that the average value of the length (diagonal length of one base) was 1.4 μm, the coefficient of variation (Cv value) of the major axis length was 8%, and the thickness (cone height) was 0.50 μm. Then, a glitter pigment (A-8) of Example 8 in the shape of a truncated quadrangular pyramid was obtained.

<Example 9>
A mold having a square uneven shape in plan view was created by photolithography, and a thin copper (Cu) film having a predetermined average film thickness was formed on the mold using electroforming (in the table, (Denoted as "electroforming"; the same applies to Example 10). After that, it goes through a peeling process that applies physical shear using brush rollers, centrifugation to remove particles with a specific gravity that is lighter than the target particles, and a purification process that includes filtration to remove dust and some upper-sized fragments. , as shown in Table 1, the average length of the major axis (diagonal of the square) is 3.1 μm, the coefficient of variation (Cv value) of the major axis length is 3%, and the thickness is 0.20 μm. A bright pigment (A-9) of Example 9 was obtained. FIG. 3 is a SEM image of the glitter pigment of Example 9.

<Example 10>
A mold having a rectangular parallelepiped uneven shape was created by photolithography, and copper (Cu) having a predetermined average thickness was electroformed in the recessed portions of the mold using electroforming. After that, it goes through a peeling process that applies physical shear using brush rollers, centrifugation to remove particles with a specific gravity that is lighter than the target particles, and a purification process that includes filtration to remove dust and some upper-sized fragments. , as shown in Table 1, the luminescence of Example 10 in the shape of a rectangular parallelepiped, having an average value of the major axis length of 3.5 μm, a coefficient of variation (Cv value) of the major axis length of 5%, and a thickness of 2.0 μm. A pigment (A-10) was obtained. FIG. 4 is a side view SEM image of the glitter pigment of Example 10.

<Comparative example 1>
A resin layer coating solution consisting of 3.0% by mass of cellulose acetate butyrate (butylation rate 35-39%, manufactured by Kanto Kagaku Co., Ltd.) and 97% by mass of isopropanol was uniformly coated on a PET film with a thickness of 100 μm using a bar coating method. A thin resin layer was formed on the PET film by coating the resin on the PET film and drying it at 60°C for 10 minutes. Next, an aluminum thin film having an average thickness of 0.02 μm was formed on the resin layer using a vacuum evaporation apparatus (Vacuum Devices Co., Ltd. model VE-1010 vacuum evaporation apparatus).

Next, the laminate of the resin layer and aluminum layer formed by the above method was immersed in diethylene glycol diethyl ether, and peeled from the PET film and micronized using a VS-150 ultrasonic dispersion machine (manufactured by As One Corporation). - A dispersion treatment was performed at the same time to obtain a bright pigment dispersion (in the table, it is marked as "vapor deposition-dispersion"; the same applies to Comparative Examples 2 and 3).

The obtained metallic pigment dispersion was filtered using a SUS mesh filter to remove coarse particles. Next, the filtrate is placed in a round-bottomed flask, and diethylene glycol diethyl ether is distilled off using a rotary evaporator. The particle size of the bright pigment is adjusted by changing the ultrasonic intensity, treatment time, and filter opening. However, as shown in Table 1, the flat plate-shaped comparative example 1 has an average value of the major axis length of 1.1 μm, a coefficient of variation (Cv value) of the major axis length of 50%, and a thickness of 0.02 μm. A bright pigment (A-11) was obtained. FIG. 5 is a SEM image of the glitter pigment of Comparative Example 1.

<Comparative example 2>
A plate-shaped comparative example 2 was prepared in the same manner as in Example 1, except that the average value of the major axis length was 2.0 μm, the coefficient of variation (Cv value) of the major axis length was 60%, and the thickness was 0.05 μm. A bright pigment (A-12) was obtained.

<Comparative example 3>
A flat plate-shaped comparative example 2 was prepared in the same manner as in Example 1, except that the average value of the major axis length was 3.1 μm, the coefficient of variation (Cv value) of the major axis length was 64%, and the thickness was 0.10 μm. A bright pigment (A-13) was obtained.

<Comparative example 4>
By using the atomization method described in Patent Document 2 and then pulverizing, the average value of the long axis length is 4.9 μm, the coefficient of variation (Cv value) of the long axis length is 36%, and the thickness is 0.10 μm. A plate-like nickel bright pigment (A-14) of Comparative Example 4 was obtained (marked as "atomized" in the table). FIG. 6 is a SEM image of the glitter pigment of Comparative Example 4.

<Comparative example 5>
Obtained by coating natural mica with a high refractive metal oxide film, the average value of the major axis length is 16.9 μm, the coefficient of variation (Cv value) of the major axis length is 69%, and the thickness is 0.50 μm. , a plate-shaped bright pearl pigment (A-15) of Comparative Example 5 was obtained (marked as "coated" in the table). FIG. 7 is a SEM image of the glitter pigment of Comparative Example 5.

[Measurement of volume-based cumulative particle diameter]
Volume-based cumulative 10% particle diameter (D10), volume-based cumulative 50% particle diameter (D50), volume-based cumulative 90% particle diameter (D90), (D90-D10)/D50, and film thickness of Examples and Comparative Examples are shown in Table 1. The particle size was measured using a laser diffraction particle size distribution meter "SALD 7500nano" manufactured by Shimadzu Corporation. Table 1 shows the measurement results.

[Measurement of filterability]
Inorganic particles were dispersed in ethanol at a concentration of 0.1 g/L, the following filter having a size approximately twice the length of the long axis of each particle was selected, and 20 ml of the solution was passed through the filter. When observed with a microscope (Keyence VHX-5000), if 5 or more particles were present on the filter, it was marked as ×, and when there were less than 5 particles, it was marked as ○. Table 1 shows the measurement results.
φ2.5μm: opening 2.5μm metal filter #2300: metal mesh (manufactured by Manabe Kogyo)
#2000: Metal mesh (manufactured by Manabe Industries)

2. Production of Ink Composition An ink composition was produced using the above-mentioned "glitter pigment dispersion". Specifically, the above glittering pigment dispersion, water (B-1), various organic solvents (B-2 to B-4), and resin (C-1: cellulose acetate butyl) shown in Table 2 were used. Inks of Examples and Comparative Examples were prepared using a rate resin, C-2: polyvinyl alcohol (degree of polymerization 500)), and a surfactant (D-1, D-2) so that the ratios were as shown in Table 3 below. After mixing the composition, the composition was stirred for 24 hours and irradiated with ultrasonic waves for 10 minutes to adjust the composition. The blending amount unit in Table 3 is mass %.

3. Evaluation Inkjet Ejection Stability Test The ejection stability of the ink compositions of Production Examples and Production Comparative Examples was evaluated. Specifically, after performing nozzle cleaning in advance, the ink compositions of Examples and Comparative Examples were filled into an inkjet head with a nozzle diameter of 20 μm and ejected. Then, the ejection was stopped for 5 minutes, the ink compositions of Examples and Comparative Examples were ejected again, and the ejection stability of the ink composition was evaluated by checking the number of bent or non-ejecting nozzles based on the following evaluation criteria. Confirmed using the following evaluation criteria.
<Evaluation criteria>
A: The number of bent or non-ejecting nozzles is less than 10% of all nozzles.
B: The number of bent or non-ejecting nozzles is 10% or more and less than 30% of all nozzles.
C: The number of bent or non-ejecting nozzles is 30% or more of all nozzles.

As can be seen from Table 3, an ink composition containing a glittering pigment with a variation coefficient of maximum length Lmax of 10% or less and having two or more rotational symmetry has inkjet ejection stability. I can see that it is something.

Claims (13)

A pigment having two or more rotational symmetry, in which the coefficient of variation of the maximum length Lmax in the projection plane when observed from the direction where the projected area of the pigment is maximum is 10% or less. The volume-based cumulative 50% particle diameter (D50) is 0.1 μm or more and 10 μm or less,
The relationship between the volume-based cumulative 10% particle diameter (D10) (μm), the volume-based cumulative 50% particle diameter (D50) (μm), and the volume-based cumulative 90% particle diameter (D90) (μm) is as follows. The pigment according to claim 1, which satisfies the relationship of formula (I).
(D90-D10)/D50≦1.0...(I) The pigment according to claim 1 or 2, wherein the pigment is a glittering pigment. The pigment according to any one of claims 1 to 3, which is used in an ink composition discharged by an inkjet method. Any one of claims 1 to 4, wherein the pigment has a first surface and a second surface that are parallel to each other, and has a polygonal shape with corners when viewed from the first surface side and the second surface side. Pigment described in Crab. The pigment according to any one of claims 1 to 5, wherein the maximum length Lmax is 0.5 μm or more and 10 μm or less. The pigment according to any one of claims 1 to 6, wherein the pigment is plate-shaped and has a thickness, which is the distance between the first surface and the second surface, of 10 nm or more and 250 nm or less. 8. The method according to claim 1, wherein a material constituting the pigment is deposited on a mold in which a plurality of uneven shapes corresponding to the shape of the pigment are formed to form a deposited film, and then the deposited film is peeled from the mold. A method for producing any of the pigments. The pigment according to any one of claims 1 to 7, wherein a substance constituting the pigment is plated on a mold in which a plurality of uneven shapes corresponding to the shape of the pigment are formed, and then the plating film is peeled from the mold. manufacturing method. An ink composition or coating composition comprising the pigment according to any one of claims 1 to 7. A coated product comprising an ink composition or a coating composition containing the pigment according to any one of claims 1 to 7 applied to the surface of a base material. A method for producing printed matter, which comprises applying an ink composition containing the pigment according to any one of claims 1 to 7 onto the surface of a substrate by an inkjet method. A recording method comprising applying an ink composition containing the pigment according to any one of claims 1 to 7 onto the surface of a base material by an inkjet method.

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