JP6974935B2 - Non-aqueous dispersion of metal nanoplates - Google Patents

Description

The present invention relates to a non-aqueous dispersion of metal nanoplates containing a dispersant and an organic solvent having specific properties.

In recent years, in the fields of optical members and optical sensors, a film having wavelength selectivity for light absorption has been demanded, and a coating material for producing such a film has been developed. As a material having wavelength selectivity for light absorption, a material that can easily control the wavelength range of light absorption in order to correspond to each application, that is, a toning design that selectively absorbs a specific wavelength in the wavelength band of the visible region. , Materials applicable to multicolor designs that combine multiple wavelengths are preferred. Such materials are expected to be applied to human body sensors, near-infrared sensors, optical sensors used in security sensors, optical devices, optical communication systems, etc. that use the wavelength band from the visible region to the near-infrared region. There is. Further, in the field of decoration technology on a base material such as plastic or glass, which requires a high-class feeling, it is expected to be applied as a coloring material showing vivid absorption or a material capable of obtaining metallic reflection.
Metallic nanoplates such as gold nanoplates and silver nanoplates are known to absorb light by localized surface plasmon resonance (LSPR), and by controlling their size and shape, the wavelength range of light absorption can be controlled. It is known to be controllable. For example, a silver nanoplate is prepared in an aqueous system, and the aqueous suspension exhibits a color corresponding to the absorption wavelength of the silver nanoplate (Patent Document 1, Non-Patent Documents 1 to 3). Since silver nanoplates are less stable and can cause the intended color change, especially when the shape changes due to oxidation, methods for preparing stable aqueous suspensions of silver nanoplates are being studied (patented). Document 1). Further, it is known that colloidal fine particles of gold or silver, that is, spherical fine particles that are not plate-shaped are dispersed in an aqueous system and used as a coloring material for ink (Patent Document 2).

International Application No. PCT / JP2015 / 065558 Japanese Unexamined Patent Publication No. 2003-292836

Science (2001), Vol. 294, pp. 1901-1903 Chemistry --A European Journal (2010), Vol. 16, No. 42, pp. 12559-12563 Langmuir (2002), Vol. 18, pp. 8692-8699

Water-based coating materials are not suitable for coating on films due to problems such as dryness, and it is necessary to use non-water-based coating materials. However, metal nanoplates such as gold nanoplates and silver nanoplates cannot be prepared in a stably dispersed state in a non-aqueous system. For example, in order to prepare a non-aqueous dispersion of silver nanoplates, the silver nanoplates must be prepared as an aqueous suspension and then water must be replaced with an organic solvent. The storage stability was low, and the particles tended to aggregate easily. Although it has been known that silver nanoplates are simply dispersed in ethanol (Non-Patent Document 3), the stability of silver nanoplates in that case remains questionable. Therefore, an object of the present invention is to provide a non-aqueous dispersion of metal nanoplates having good stability.
It is also an object of the present invention to provide a method for adjusting the maximum absorption wavelength of a metal nanoplate or a dispersion thereof.

As a result of diligent studies to solve the above problems, the present inventors can prepare a non-aqueous dispersion of metal nanoplates having good stability by using a dispersant having specific properties, and metal nanos. We have found that the properties of the plate or dispersion medium correlate with the maximum absorption wavelength, completing the present invention.
That is, the present invention relates to a non-aqueous dispersion of a metal nanoplate and a solid composition for preparing the following, a non-aqueous paint of the metal nanoplate and a coating film formed from the same, and a metal nanoplate or a metal nanoplate. It provides a method of adjusting the maximum absorption wavelength of the dispersion.
[1] A non-aqueous dispersion of metal nanoplates containing a dispersant and an organic solvent.
A non-aqueous dispersion liquid characterized in that the acid value of the dispersant is 90 or less and the base value of the dispersant is 5 to 100.
[2] The non-aqueous dispersion liquid according to the above [1], wherein the metal is gold or silver.
[3] The non-aqueous dispersion liquid according to the above [1] or [2], wherein the ratio of the acid value of the dispersant to the base value is acid value / base value = 2.0 or less.
[4] The non-aqueous dispersion liquid according to any one of [1] to [3] above, wherein the dispersant has a weight average molecular weight Mw of 10,000 or more.
[5] The non-aqueous dispersion liquid according to any one of the above [1] to [4], wherein the solubility parameter (SP value) of the organic solvent is 8 to 12.
[6] The non-aqueous dispersion according to any one of [1] to [5] above, wherein the organic solvent contains at least one selected from the group consisting of aromatic hydrocarbons, ketones, esters and ethers. liquid.
[7] A solid composition containing a dispersant and a metal nanoplate for preparing a non-aqueous dispersion of a metal nanoplate.
A solid composition, wherein the acid value of the dispersant is 90 or less, and the base value of the dispersant is 5 to 100.
[8] The solid composition according to the above [7], wherein the ratio of the acid value of the dispersant to the base value is acid value / base value = 2.0 or less.
[9] The solid composition according to the above [7] or [8], wherein the dispersant has a weight average molecular weight Mw of 10,000 or more.
[10] A non-aqueous coating material for a metal nanoplate containing the non-aqueous dispersion liquid according to any one of the above [1] to [6] and a binder.
[11] A coating film of a metal nanoplate formed from the non-aqueous dispersion liquid according to any one of the above [1] to [6] or the non-aqueous paint according to the above [10].
[12] The non-aqueous dispersion liquid according to any one of the above [1] to [6], which is used for a member for light control, a member for utilizing electrical characteristics, or a sensor-related member.
[13] The non-aqueous paint according to the above [10], which is used for a member that controls light, a member that utilizes electrical characteristics, or a member related to a sensor.
[14] The coating film according to the above [11], which is used for a member for light control, a member for utilizing electrical characteristics, or a sensor-related member.
[15] The non-aqueous dispersion according to any one of [1] to [6] and [12], the solid composition according to any one of [7] to [9], and the above [ 10] or [13] is a method for adjusting the maximum absorption wavelength of the metal nanoplate used for the non-aqueous paint or the coating film according to [11] or [14].
The step of increasing the particle size of the metal nanoplate to shift the maximum absorption wavelength of the metal nanoplate to the longer wavelength side, or decreasing the particle size of the metal nanoplate to maximize the absorption of the metal nanoplate. A method comprising the step of shifting the wavelength to the short wavelength side.
[16] A method for adjusting the maximum absorption wavelength of a metal nanoplate in a non-aqueous dispersion.
The step of increasing the particle size of the metal nanoplate to shift the maximum absorption wavelength of the metal nanoplate to the longer wavelength side, or decreasing the particle size of the metal nanoplate to maximize the absorption of the metal nanoplate. A method comprising the step of shifting the wavelength to the short wavelength side.
[17] The step of increasing or decreasing the particle size is a step of preparing a metal nanoplate having a particle size of about 10 nm to about 30 nm and adjusting the maximum absorption wavelength of the metal nanoplate to about 420 nm to about 530 nm. A step of preparing a metal nanoplate having a diameter of about 30 nm to about 50 nm and adjusting the maximum absorption wavelength of the metal nanoplate to about 470 nm to about 640 nm, or a metal nanoplate having a particle diameter of about 50 nm to about 200 nm. The method according to [15] or [16] above, comprising the step of preparing and adjusting the maximum absorption wavelength of the metal nanoplate to about 520 nm to about 1350 nm.
[18] The method for adjusting the maximum absorption wavelength of the non-aqueous dispersion liquid according to any one of the above [1] to [6] and [12].
A step of substituting at least a part of the organic solvent (first organic solvent) in the non-aqueous dispersion liquid with a second organic solvent, or an organic solvent (first organic solvent) in the non-aqueous dispersion liquid. Including the step of adding a second organic solvent,
In the replacement step or the addition step, a liquid having a higher refractive index than the first organic solvent is adopted as the second organic solvent, and the maximum absorption wavelength of the non-aqueous dispersion liquid is used as the dispersion medium. A step of shifting to a longer wavelength side than the maximum absorption wavelength of the non-aqueous dispersion liquid containing only the organic solvent of the above, or adopting a liquid having a lower refractive index than the first organic solvent as the second organic solvent. The method comprising a step of shifting the maximum absorption wavelength of the non-aqueous dispersion liquid to a shorter wavelength side than the maximum absorption wavelength of the non-aqueous dispersion liquid containing only the first organic solvent as a dispersion medium. ..
[19] A method for adjusting the maximum absorption wavelength of the dispersion liquid of the metal nanoplate containing the first dispersion medium.
A step of replacing at least a part of the first dispersion medium with a second dispersion medium, or a step of adding a second dispersion medium to the first dispersion medium is included.
The replacement step or the addition step employs a liquid having a higher refractive index than the first dispersion medium as the second dispersion medium, and uses the maximum absorption wavelength of the dispersion as the first dispersion medium as the dispersion medium. The step of shifting to a longer wavelength side than the maximum absorption wavelength of the dispersion liquid containing only, or by adopting a liquid having a refractive index lower than that of the first dispersion medium as the second dispersion medium, the dispersion liquid A method comprising a step of shifting the maximum absorption wavelength to a shorter wavelength side than the maximum absorption wavelength of a dispersion liquid containing only the first dispersion medium as the dispersion medium.
[20] The method for preparing a non-aqueous dispersion according to any one of the above [1] to [6] and [12].
The metal nanoplate is dispersed in an organic solvent having a refractive index higher than that of water, and the maximum absorption wavelength of the non-aqueous dispersion is shifted to a longer wavelength side than the maximum absorption wavelength of the aqueous dispersion of the metal nanoplate. The maximum absorption wavelength of the non-aqueous dispersion liquid is shifted to a shorter wavelength side than the maximum absorption wavelength of the water dispersion liquid of the metal nanoplate by dispersing in an organic solvent having a refractive index lower than that of water. A method comprising steps.

According to the present invention, a non-aqueous dispersion of metal nanoplates having good stability can be prepared. Then, by using the non-aqueous dispersion liquid, it becomes possible to prepare a non-aqueous paint of a metal nanoplate, and further to form a film thereof to prepare a coating film. Further, according to the present invention, the maximum absorption wavelength of the metal nanoplate or its dispersion can be easily adjusted.

The optical characteristics of the aqueous dispersion A (A), the toluene dispersion E (E), and the propylene glycol monomethyl ether dispersion Z (Z) of the silver nanoplate and the transmittance of the coating film Z'(Z') are shown. The optical characteristics of the aqueous dispersion B (B), the toluene dispersion F (F) and the propylene glycol monomethyl ether dispersion AC (AC) of the silver nanoplate and the transmittance of the coating film AC'(AC') are shown. The optical characteristics of the aqueous dispersion C (C), the toluene dispersion G (G) and the propylene glycol monomethyl ether dispersion AF (AF) of the silver nanoplate and the transmittance of the coating film AF'(AF') are shown. The optical characteristics of the aqueous dispersion D (D), the toluene dispersion H (H), and the propylene glycol monomethyl ether dispersion AI (AI) of the silver nanoplate are shown. The relationship between the maximum absorption wavelength and the half width of the non-aqueous dispersion of silver nanoplates is shown. The optical characteristics of the aqueous dispersion A (A), the propylene glycol monomethyl ether dispersion Z (Z), and the propylene glycol monomethyl ether dispersion AM-1 (AM-1) of the silver nanoplate are shown. The relationship between the particle size of the silver nanoplate and the maximum absorption wavelength is shown. Acetone (AT), methyl ethyl ketone (MK), propylene glycol monomethyl ether (PM), propylene glycol monomethyl ether acetate (PMA), diacetone alcohol (DA), cyclohexanone (CH), or toluene (TL) was used as the dispersion medium. The optical characteristics of the non-aqueous dispersion of silver nanoplates are shown. The relationship between the refractive index of the dispersion medium and the maximum absorption wavelength of the non-aqueous dispersion liquid is shown. The transmittance of the coating film AN'(AN'), the coating film AO'(AO'), or the coating film AP'(AP') using silver nanoplates having different particle sizes is shown.

Hereinafter, the present invention will be described in more detail.
The non-aqueous dispersion of the metal nanoplate of the present invention contains a dispersant and an organic solvent, the acid value of the dispersant is 90 or less, and the base value of the dispersant is 5 to 100. It is characterized by that.

As used herein, the term "metal nanoplate" refers to plate-like nanoparticles made from metal. The particle size (corresponding to the diameter in the case of a circle and the length of the maximum side in the case of a triangle) which is the maximum length of the main surface of the metal nanoplate is usually 10 to 1000 nm, and 10 to 150 nm. preferable. The thickness of the metal nanoplate is not particularly limited as long as it can absorb plasmons, and is generally 40 nm or less, preferably 5 to 20 nm.
The metal used as the material of the metal nanoplate is not particularly limited as long as it can absorb light by LSPR when it is made into a nanoplate, and is, for example, gold (Au), silver (Ag), palladium (Pd). ), Copper (Cu), Lead (Pb), Bismus (Bi), Cobalt (Co), Nickel (Ni), or Tin (Sn), preferably gold or silver.
The aspect ratio (particle size / thickness) of the metal nanoplate is usually 1.5 or more, and 1.5 to 10 is preferable because the absorption wavelength of LSPR is expressed in the visible light region and multicolor design is possible. For example, in the case of a silver nanoplate used for detection in near-infrared light, if an aspect ratio such that LSPR is expressed at 800 to 2000 nm (for example, LSPR is expressed near 900 nm at an aspect ratio of 11) is used. good.
The shape of the metal nanoplate is not particularly limited as long as it can absorb plasmons, and a shape corresponding to the intended color can be adopted. For example, the metal nanoplate may have a polygonal shape such as a triangular shape, a pentagonal shape, and a hexagonal shape, or a circular shape having curved corners. In the present invention, a single type (single shape) of metal nanoplates may be used, or a mixture of a plurality of types of metal nanoplates having different shapes may be used.

The size (maximum length of the main surface; particle size), aspect ratio, and shape of the metal nanoplate can be appropriately set according to the intended color or maximum absorption wavelength. The maximum absorption wavelength of the metal nanoplate may be adjusted in the range of 430 to 2000 nm, preferably in the range of 430 to 1500 nm, and particularly preferably in the range of 430 to 1000 nm. The relationship between the size and shape of the metal nanoplate and the color is described in Japanese Patent Publication No. 2011-508072. For example, if the silver nanoplate has a triangular shape and a hexagonal shape (maximum length of main surface: 20 nm, thickness: 5.1 nm), magenta (maximum absorption wavelength: 538 nm) can be exhibited. When a gold nanoplate is used instead of the silver nanoplate, the gold nanoplate has the maximum absorption wavelength on the longer wavelength side even if it has the same shape. Further, the maximum absorption wavelength of the metal nanoplate is stabilized after coating with another metal after forming the metal nanoplate, adjusting the pH of the suspension, and / or carrying a specific binding substance to the test substance.
The Munsell value (hereinafter, simply referred to as the Munsell value) of the Munsell color system, which is one of the Munsell color systems that quantitatively express colors, is 5Y 8.5 / 14, and the coordinates of the CIE1931xy chromaticity diagram (hereinafter, also referred to simply as the Munsell value). Hereinafter, it is also simply referred to as chromaticity coordinates) yellow (yellow color, metal nanoplate expressing LSPR in the vicinity of 400 to 500 nm) having x: 0.4498 and y: 0.4811, and a Munsell value of 5RP 5/14. Magenta (magenta color, metal nanoplate expressing LSPR near 500 to 600 nm) with chromaticity coordinates x: 0.4142, y: 0.2428, Munsell value 7.5B 6/10, Arbitrary by adjusting the aspect ratio of the metal nanoplate such as cyan (cyan color, metal nanoplate expressing LSPR near 600 to 750 nm) whose chromaticity coordinates are x: 0.1934 and y: 0.2374. The absorption wavelength of LSPR can be selected. It is also possible to perform multicolor design by subtractive mixing using three or more kinds of metal nanoplates having different aspect ratios that express yellowish colors, magentaish colors, and cyanish colors as the three primary colors.
As the metal nanoplate, a commercially available product may be used, or a metal nanoplate manufactured according to a known manufacturing method or a method described in Examples described later may be used. Usually, metal nanoplates are prepared in an aqueous suspension.

The surface of the metal nanoplate may be coated with a metal other than the metal constituting the nanoplate. For example, in the case of a silver nanoplate, the surface may be coated with gold, platinum, palladium, silica, or the like. May be good. By covering the surface of the metal nanoplate with such another metal, its oxidation resistance can be improved. The thickness of the coating is not particularly limited as long as it does not affect the color development performance of the metal nanoplate, but the average thickness is preferably 1.0 nm or less, more preferably 0.7 nm or less. When the thickness of the coating is 1.0 nm or less, the oxidation of the metal nanoplate can be suppressed while maintaining the plasmon absorption of the metal nanoplate. The lower limit of the thickness of the coating is not particularly limited as long as it can achieve the purpose of coating the surface of the metal nanoplate, but the average thickness is preferably 0.1 nm or more or 0.3 nm. For example, when the silver nanoplate is coated with gold, the average thickness of the gold is the thickness of the gold on the surface of the silver nanoplate measured by high-angle scattering annular dark-field scanning transmission microscopy (HAADF-STEM). It may be calculated from. For example, from the HAADF-STEM image, the thickness of gold is measured for 10 points of arbitrary parts in 10 arbitrary particles, that is, 100 points in total, and the average value of 80 points excluding the upper and lower 10% of the data is obtained. The average thickness of gold may be used.
The coating method is not particularly limited as long as it can achieve the object of coating the surface of the metal nanoplate, and a known coating method can be used.

When the metal nanoplate is coated, the entire surface of the metal nanoplate may be coated with a coating material, or a part of the surface thereof may be coated. The fact that all or part of the surface of the metal nanoplate is coated with the coating material can be confirmed by various commonly used methods such as observation with an electron microscope and measurement of physicochemical properties. For example, when all or part of the surface of a silver nanoplate is coated with a coating material, it becomes more stable to acid or sodium or chloride ions and more stable to oxidation. Then, after the coating treatment, the harsh conditions for the silver nanoplate in an acidic solution (eg, 2% hydrogen peroxide solution) or buffer (eg, 10 mM phosphate buffered saline (with or without divalent ions)). If the optical properties (maximum absorption wavelength) of a suspension of silver nanoplates are measured below and the optical properties change only slightly compared to those measured in water, then the silver nanoplates are coated. It can be judged that it is covered with a material. It can also be confirmed by analyzing the elements in the suspension of the metal nanoplate that the metal nanoplate is coated with the coating material.

The "dispersant" described in the present specification is a component for migrating a metal nanoplate dispersed in an aqueous phase into an organic phase and uniformly dispersing the metal nanoplate in the organic phase. To say. Dispersants are characterized by acid and base values. The "acid value" refers to the number of milligrams (unit: mg KOH / g) of potassium hydroxide required to neutralize the acidic component present in 1 g of the sample, and is defined by JIS K2501: 2003. It can be measured by the method. The "base value" (sometimes also referred to as "amine value") is the number of milligrams of hydrochloric acid or perchloric acid equivalent to potassium hydroxide required to neutralize the basic components contained in 1 g of the sample. (Unit: mg KOH / g), which can be measured by the method specified in JIS K2501: 2003. The acid value of the dispersant used in the non-aqueous dispersion of the metal nanoplate of the present invention is 90 or less (including 0), and the base value is 5 to 100. The acid value is preferably in the range of 0 to 70, more preferably 0 to 50. The preferred range of the base value is 5 to 70, and more preferably 5 to 40. When a dispersant having an acid value of 90 or less and a base value of 5 or more is used, the metal nanoplate can be easily transferred from the aqueous phase to the organic phase, and a non-aqueous dispersion liquid of the metal nanoplate can be efficiently prepared. can. When a dispersant having a base value of 100 or less is used, aggregation, particle growth or excessive reduction of the metal nanoplate is less likely to occur, metallic luster is not generated, and the optical properties peculiar to the metal nanoplate can be maintained. The ratio of the acid value to the base value may be, for example, acid value / base value = 2.0 or less, preferably 1.1 or less, and more preferably 0.9 or less.
Examples of the dispersant having the above characteristics include "DisperBYK" manufactured by Big Chemie Japan Co., Ltd., "Azipar" manufactured by Ajinomoto Fine Techno Co., Ltd., "Solspurs" manufactured by Japan Lubrizol Co., Ltd., or Kyoeisha Chemical Co., Ltd. A product that satisfies the acid value and the basic value (amine value) specified in the present invention may be adopted from the above-mentioned "Floren", and specifically, DisperBYK108, DisperBYK142, DisperBYK145, DisperBYK164, DisperBYK185, DisperBYK2001. , DisperBYK2008, DisperBYK2013, DisperBYK2022, DisperBYK2025, DisperBYK2050, DisperBYK2150, DisperBYK9076, DisperBYK9077, SOLSPERSE 11200, SOLSPERSE 13240, SOLSPERSE 13940, SOLSPERSE 20000, SOLSPERSE 24000SC, SOLSPERSE 24000GR, Solsperse 32000, SOLSPERSE 33000, SOLSPERSE 34750, SOLSPERSE 35100, SOLSPERSE 37500, Solspers 39000, Floren DOPA-15BHFS, Floren DOPA-17HF, Floren DOPA-35, Floren DOPA-35, Azispar PB821, Ajispar PB822, Ajispar PB824, Ajispar PB881 and the like can be adopted. These may be compounds having a nitrogen atom (for example, an amino group) which is an element highly adsorbent to a metal nanoplate in the main chain and having a side chain having an affinity for a non-aqueous solvent. The acid value and base value (amine value) of the dispersant are disclosed by a data sheet prepared by the manufacturer.
The weight average molecular weight Mw of the dispersant used in the non-aqueous dispersion of the metal nanoplate of the present invention may be, for example, 10,000 or more, preferably 20,000 or more, and more preferably 30,000 to. It is 100,000. When such a dispersant is used, the dispersibility of the metal nanoplate in a non-aqueous solvent is improved as compared with the case where a dispersant having an Mw of less than 10,000 is used, and the color tone change due to oxidation or the like is less likely to occur. Therefore, the optical characteristics peculiar to the metal nanoplate can be maintained more stably. Further, when a dispersant having a molecular weight of 10,000 or more and a solid at room temperature is used, a solid composition containing a metal nanoplate can be easily obtained. On the other hand, a dispersant having a molecular weight of 100,000 or less has high solubility in an organic solvent and can be advantageously used as a dispersant. The molecular weight of the dispersant may be measured by a mass spectrometer (for example, high-speed GPC apparatus HLC-8320GPC, Tosoh Corporation) usually used for the measurement.

The organic solvent contained in the non-aqueous dispersion liquid of the metal nanoplate of the present invention is used as a dispersion medium for dispersing the metal nanoplate. As the organic solvent, as long as the metal nanoplate can be dispersed in the presence of the dispersant, an ordinary organic solvent can be adopted without particular limitation. The organic solvent may contain, for example, one or more selected from the group consisting of hydrocarbons, ketones, esters and ethers, preferably toluene (SP value 8.9), xylene (SP value 8.8). , Ethyl acetate (SP value 9.1), Butyl acetate (SP value 8.5), Acetone (SP value 9.9), Methyl ethyl ketone (SP value 9.3), Methyl isobutyl ketone (SP value 8.4), Selected from the group consisting of diacetone alcohol (SP value 9.2), cyclohexanone (SP value 9.9), propylene glycol monomethyl ether (SP value 10.1) and propylene glycol monomethyl ether acetate (SP value 8.7). Includes one or more species.
The solubility parameter (SP value) (unit: (cal / cm ³ ) ^1/2 ) of the organic solvent may be, for example, 8 to 12 when determined from the latent heat of vaporization, preferably 9 to 11. be. Here, the solubility parameter is a value defined by the regular solution theory introduced by Hildebrand, and is used as an index of solubility and compatibility of a solvent or an organic compound. The solubility parameter can be obtained by a known method from the structure and physical characteristics of the chemical substance. When an organic solvent having an SP value of 12 or less is used, the transition from the aqueous phase to the organic phase becomes easy. Further, when an organic solvent having an SP value in the range of 8 to 12 is used, the dispersion stability of the metal nanoplate is improved.

The non-aqueous dispersion of the metal nanoplate of the present invention is a dispersion using the organic solvent as the main dispersion medium. Mixing of a small amount of water derived from a manufacturing process or the like, for example, mixing of 1% by mass or less of water is permitted, but the non-aqueous dispersion liquid does not substantially contain water.

The non-aqueous dispersions, paints or coatings of the metal nanoplates of the present invention have specific optical properties (eg, maximum absorption wavelength, reflection, polarization, etc.) and electrical properties (eg, maximum absorption wavelength, reflection, polarization, etc.) based on the metal nanoplates contained therein. For example, since it has conductivity), it can be applied to a member that controls light or a member that utilizes electrical characteristics. Examples of the member for controlling light include a coloring material, a bright material, a decorative material, a reflective material, a polarizing material, and a near-infrared absorber. As the coloring material, a metal nanoplate prepared to have an aspect ratio that absorbs a target wavelength in the wavelength band in the visible region can be dispersed and used in a medium such as a solvent or a resin. In this case, when the distance of the metal nanoplates in the medium is close, a change in absorption wavelength called plasmon coupling (change to broad absorption toward the long wavelength side) is confirmed, so the morphology is isolated and dispersed at a distance greater than the particle radius. Is desirable. Further, by mixing a plurality of metal nanoplates having different aspect ratios, it is possible to design in a wide color reproduction range. Furthermore, the shape of the metal nanoplate can be adjusted so that it can be selectively absorbed, transmitted or reflected in the wavelength band from the visible region to the near infrared region and further to the millimeter wave region. , In the field of optical communication systems, it can be used for human body sensors, near infrared sensors, security sensors, environment recognition sensors (for example, millimeter wave radars, laser radars, image sensors, ultrasonic sensors, etc.), magic mirrors, and the like. In addition, anti-counterfeit ink containing metal nanoplates can be used as a security material. Further, in the field of decoration technology on a base material such as plastic or glass, it can be applied as a coloring material (structural color) using transmitted light or a metallic reflective material. For example, silver, which is a precious metal, has a high reflectance, and a silver nanoplate having a plate-like shape can obtain a bulk silver-like white silver luster by arranging the interparticle distances closely on the substrate. In addition, metals such as gold and silver have high conductivity, and as a heat dissipation material for the purpose of releasing heat generated by electrical / electronic parts, wiring materials used for mounting parts, electrode materials, electromagnetic wave shielding materials, and electrical parts. Available. In particular, since the metal nanoplate having a plate-like shape has a large contact area between particles, the effect of enhancing conductivity and heat conduction can be obtained. Since the electric field enhancing effect can be obtained at the edge portion of the metal nanoplate particles, it can be used as a Raman enhancer or a sensitizer. Further, the metal nanoplate can convert light into heat by electronic vibration, and can be used as a photothermal conversion material for converting light having a specific wavelength depending on the aspect ratio into heat. When a metal nanoplate is placed on a substrate, it can be used as a recording material or a security material by identifying the arrangement pattern. Furthermore, for the purpose of enhancing the functionality and reliability of optical members and optical sensors, optical control functions such as absorption, transmission, reflection, polarization, conductivity, heat dissipation, light enhancement function, and photothermal conversion function, electrical characteristics, sensing function, and shape The characteristics may be combined, and for example, it can be used as a security material that has a plurality of pieces of information and is difficult to be forged.

The non-aqueous dispersion of the metal nanoplate of the present invention can be prepared by substituting the aqueous dispersion of the metal nanoplate prepared by a known method with the organic solvent containing the dispersant by a known method. .. For example, when the organic solvent containing the dispersant is added to the aqueous dispersion of the metal nanoplate and mixed by shaking, the metal nanoplate is transferred from the aqueous dispersion to the organic solvent. Then, by extracting this organic solvent, a non-aqueous dispersion of metal nanoplates can be prepared. Centrifugation of the prepared non-aqueous dispersion of metal nanoplates precipitates the metal nanoplates and dispersants, which may be redispersed in another organic solvent for additional substitution. .. Since this sediment also contains a dispersant that adheres to the metal nanoplate and is settled together, the non-aqueous dispersion of the metal nanoplate after substitution is also a non-aqueous dispersion of the metal nanoplate of the present invention. It corresponds to an aqueous dispersion and shows a spectral spectrum equivalent to that of the non-aqueous dispersion of the metal nanoplate before replacement.

In another aspect, the invention relates to a solid composition for the preparation of a non-aqueous dispersion of said metal nanoplates, which comprises a dispersant and a metal nanoplate. The solid composition of the present invention may be prepared, for example, by removing the non-aqueous dispersion of the metal nanoplate of the present invention once prepared and drying it. By adding an organic solvent to the solid composition of the present invention and redistributing the metal nanoplates, the non-aqueous dispersion of the metal nanoplates of the present invention can be prepared again. The non-aqueous dispersion of the metal nanoplate prepared by redispersion shows a spectral spectrum equivalent to that of the non-aqueous dispersion before preparation of the solid composition.

In yet another aspect, the invention relates to a non-aqueous coating of a metal nanoplate, which comprises a non-aqueous dispersion of the metal nanoplate and a binder. The "binder" described in the present specification is a main component that forms a coating film together with a metal nanoplate, and various resins that do not deteriorate the performance of the metal nanoplate can be used without particular limitation. Examples of the binder include resins such as acrylic resin, polyester resin, alkyd resin, urethane resin, silicone resin, fluororesin, epoxy resin, polycarbonate resin, polyvinyl chloride resin, and polyvinyl alcohol, and radically polymerizable oligomers and monomers. Further, alkoxysilane and an inorganic resin obtained by polycondensing it can be mentioned.
Among them, the active energy ray-curable non-aqueous paint is more preferable because it has a feature that a film can be formed in a short time. The active energy ray-curable non-aqueous paint can be prepared by blending a radically polymerizable monomer or oligomer as a binder, or can be prepared by blending a cationically polymerizable monomer or oligomer.
Examples of the radically polymerizable monomer and oligomer include known monofunctional (meth) acrylates, bifunctional or higher polyfunctional (meth) acrylates, and urethane acrylate oligomers. Examples of the monofunctional (meth) acrylate include stearyl acrylate, acryloylmorpholine, tridecyl acrylate, lauryl acrylate, N, N-dimethylacrylamide, decyl acrylate, phenoxyethyl acrylate, isodecyl acrylate, isobornyl acrylate, and dicyclopenta. Nyl acrylate, dicyclopentenyl acrylate, isooctyl acrylate, octyl acrylate, dicyclopentenyloxyethyl acrylate, cyclohexyl acrylate, N-vinylcaprolactam, isoamyl acrylate, 2-ethylhexyl-diglycol acrylate, EO (ethylene oxide) modified 2-ethylhexyl acrylate , Neopentyl glycol acrylic acid benzoic acid ester, N-vinyl-2-pyrrolidone, N-vinylimidazole, tetrahydrofurfuryl acrylate, methoxydipropylene glycol acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4) -Il) Methyl acrylate, cyclic trimethylol propaneformal acrylate, ethoxy-diethylene glycol acrylate and the like can be mentioned.
Examples of the bifunctional or higher polyfunctional (meth) acrylate include 1,10-decanediol diacrylate, 2-methyl-1,8-octanediol diacrylate, and 2-butyl-2-ethyl-1,3-propanediol diacrylate. Acrylate, 1,9-nonanediol diacrylate, 1,8-octanediol diacrylate, 1,7-heptanediol diacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, polytetramethylene Glycol diacrylate, 3-methyl-1,5-pentanediol diacrylate, neopentyl glycol diacrylate hydroxypivalate, neopentyl glycol diacrylate, PO (propylene oxide) modified neopentyl glycol diacrylate, tetraethylene glycol diacrylate, Triethylene glycol diacrylate, tripropylene glycol diacrylate, and dipropylene glycol diacrylate, trimethylol propane triacrylate, ethoxylated trimethylol propane triacrylate, propoxylated trimethylol propane triacrylate, ethoxylated glycerin triacrylate, pentaerythritol tetra. Examples thereof include acrylate, ethoxylated pentaerythritol tetraacrylate, EO-modified diglycerin tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, and EO-modified dipentaerythritol hexaacrylate. Further, in order to cure the radically polymerizable monomer or oligomer, a normal photopolymerization initiator can be used without particular limitation. For example, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-1-{4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one, 2-Hydroxy-2-methyl-1-phenyl-propane-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, etc. can be used as the radically polymerizable monomer. Or oligomers may be used for curing.
Examples of the cationically polymerizable monomer or oligomer include an epoxy compound, a vinyl ether compound, an oxetane compound, an oxolan compound, a cyclic acetal compound, a cyclic lactone compound, a thilane compound, a thiovinyl ether compound, a spiro orthoester compound, and an ethylenically unsaturated compound. , Cyclic ether compounds, cyclic thioether compounds and the like.

In yet another aspect, the invention relates to a coating of a metal nanoplate, which is formed from a non-aqueous dispersion or non-aqueous paint of the metal nanoplate. Since the coating film formed from the non-aqueous dispersion liquid or the non-aqueous paint contains a metal nanoplate, it can be designed to exhibit various colors based on its maximum absorption wavelength. (Note that the term "film-formed" merely specifies the composition of the coating film by indicating the state, and does not specify the manufacturing method of the coating film.)
The method for forming the coating film of the metal nanoplate is not particularly limited, and a conventionally known method can be used. For example, dipping method, spray method, bar coat method, roll coater method, reverse roll coater method, kiss coater method, blade coater method, slide coater method, slit die coat method, screen printing method, flow coater method, spin coater method, letterpress printing. A method, intaglio printing (gravure printing, etc.), an inkjet method, a dispenser (liquid fixed-quantity ejection device), or the like can be used.

The spectral spectra of the non-aqueous dispersion liquid, non-aqueous coating material, and coating film of the metal nanoplate of the present invention can be evaluated by measuring the absorbance or quenching degree by a known method. Absorbance refers to the strength of light absorption of an object when parallel light rays pass through the object (absorbance in a narrow sense), but in actual measurement, light loss due to reflection or scattering on the surface of the object is also taken into consideration. Need to be (absorbance in a broad sense). Absorbance in a broad sense, which means the intensity of light loss due to all factors such as light absorption, reflection and scattering, is particularly referred to herein as quenching. The extinction or absorbance may be measured by an ultraviolet-visible spectrophotometer usually used for these measurements (for example, an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC, Shimadzu Corporation). Further, in the case of the coating film of the metal nanoplate of the present invention, the optical characteristics may be evaluated by the light transmittance. The coating film has a maximum absorption wavelength corresponding to the characteristics of the metal nanoplate, and exhibits a minimum transmittance at the maximum absorption wavelength.

The non-aqueous dispersions, non-aqueous paints, and coatings of the metal nanoplates of the present invention have good stability, for example, in a good dispersion state of the metal nanoplates during their preparation process or storage after preparation. It has excellent properties such as maintaining the above, not causing aggregation or deformation of the metal nanoplate, or maintaining the optical properties of the metal nanoplate or the sharpness of the peak of the maximum absorption wavelength. The sharpness of the peak of the maximum absorption wavelength may be evaluated by the half width of the peak. As used herein, the term "full width at half maximum" refers to the difference (nm) between two wavelengths that indicates half the value of the absorbance or quenching of the maximum absorption wavelength on both sides of the maximum absorption wavelength. .. In general, the half-value width of the peak of the maximum absorption wavelength of the metal nanoplate becomes larger as the wavelength becomes longer, so that the range of the half-value width that can be said to be "sharp" changes according to the maximum absorption wavelength. For example, the value of the half-value width of a non-aqueous dispersion liquid, a non-aqueous paint, or a coating film of a silver nanoplate is expressed by the following equation:
Half width [nm] = maximum absorption wavelength [nm] x 0.50-157 ± 40
When it is included in the range of the value represented by (see FIG. 5 if necessary), it may be determined that the peak of the maximum absorption wavelength is "sharp".

In another aspect, the invention relates to a method of adjusting the maximum absorption wavelength of a metal nanoplate in a non-aqueous dispersion, in which the particle size of the metal nanoplate and its maximum absorption wavelength are positively correlated. Based on the discovery that it is in. That is, the method of adjusting the maximum absorption wavelength of the metal nanoplate of the present invention is a step of increasing the particle size of the metal nanoplate to shift the maximum absorption wavelength of the metal nanoplate to the long wavelength side, or the above-mentioned step. It includes a step of reducing the particle size of the metal nanoplate to shift the maximum absorption wavelength of the metal nanoplate to the short wavelength side.

The maximum absorption wavelength of the metal nanoplate depends not only on the particle size of the metal nanoplate, but also on its aspect ratio and shape, and the characteristics of the dispersion medium of the metal nanoplate, but only the particle size. In order to prepare a metal nanoplate having a maximum absorption wavelength of about 420 nm to about 530 nm, a particle size of about 10 nm to about 30 nm is preferable, and a metal nanoplate having a maximum absorption wavelength of about 470 nm to about 640 nm is prepared. For this purpose, a particle size of about 30 nm to about 50 nm is preferable, and for preparing a metal nanoplate having a maximum absorption wavelength of about 520 nm to about 1350 nm, a particle size of about 50 nm to about 200 nm is preferable.

In yet another aspect, the present invention relates to a method of adjusting the maximum absorption wavelength of the dispersion liquid of the metal nanoplate containing the first dispersion medium, and this method relates to a method of adjusting the dispersion medium constituting the dispersion liquid of the metal nanoplate. It is based on the discovery that the refractive index and the maximum absorption wavelength of the dispersion have a positive correlation. That is, the method of adjusting the maximum absorption wavelength of the dispersion liquid of the metal nanoplate containing the first dispersion medium of the present invention is a step of replacing at least a part of the first dispersion medium with a second dispersion medium, or a step of replacing at least a part of the first dispersion medium with a second dispersion medium. The step of adding the second dispersion medium to the first dispersion medium is included, and the replacement step or the addition step has a higher refractive index than the first dispersion medium as the second dispersion medium. A step of adopting a liquid and shifting the maximum absorption wavelength of the dispersion liquid to a longer wavelength side than the maximum absorption wavelength of the dispersion liquid containing only the first dispersion medium as the dispersion medium, or the second dispersion medium. By adopting a liquid having a refractive index lower than that of the first dispersion medium, the maximum absorption wavelength of the dispersion liquid is set to a shorter wavelength side than the maximum absorption wavelength of the dispersion liquid containing only the first dispersion medium as the dispersion medium. It includes a step of shifting to. The refractive index of the solution that can be used as a dispersion medium for metal nanoplates is known, for example, the refractive index of trifluoroethanol is 1.29, the refractive index of methyl alcohol is 1.33, and the refractive index of water is 1.33. Refraction of acetone is 1.36, refraction of methyl ethyl ketone is 1.38, refraction of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate is 1.40, refraction of diacetone alcohol is 1.42, refraction of cyclohexanone. The rate is 1.45 and the refractive index of toluene is 1.50.

When the dispersion liquid of the metal nanoplate containing the first dispersion medium is the non-aqueous dispersion liquid of the metal nanoplate containing the first organic solvent, the non-aqueous dispersion liquid of the metal nanoplate of the present invention. The method for adjusting the maximum absorption wavelength includes a step of replacing at least a part of the first organic solvent with a second organic solvent, or a step of adding a second organic solvent to the first organic solvent. The replacement step or the addition step employs a liquid having a higher refractive index than the first organic solvent as the second organic solvent, and sets the maximum absorption wavelength of the non-aqueous dispersion liquid as a dispersion medium. As a step of shifting to a longer wavelength side than the maximum absorption wavelength of the non-aqueous dispersion liquid containing only the first organic solvent, or as the second organic solvent, a liquid having a lower refractive index than the first organic solvent. The present invention comprises a step of shifting the maximum absorption wavelength of the non-aqueous dispersion liquid to a shorter wavelength side than the maximum absorption wavelength of the non-aqueous dispersion liquid containing only the first organic solvent as the dispersion medium.

Further, when preparing a non-aqueous dispersion liquid from the aqueous dispersion liquid of the metal nanoplate, the dispersion medium of the dispersion liquid of the metal nanoplate is replaced with an organic solvent from water, so that the dispersion liquid of the metal nanoplate is used. It can be said that the maximum absorption wavelength is changed. That is, when the metal nanoplate is dispersed in an organic solvent having a refractive index higher than that of water, the maximum absorption wavelength of the non-aqueous dispersion is longer than the maximum absorption wavelength of the water dispersion of the metal nanoplate. When shifted to the wavelength side and dispersed in an organic solvent having a refractive index lower than that of water, the maximum absorption wavelength of the non-aqueous dispersion is shorter than the maximum absorption wavelength of the aqueous dispersion of the metal nanoplate. Shift to.

Hereinafter, the present invention will be specifically described with reference to Examples, but the scope of the present invention is not limited to these Examples.

1. 1. Preparation of non-aqueous dispersion of silver nanoplate 1-1. Preparation of silver nanoplate aqueous dispersion (mother solution) 1-1-1. Preparation of seed particles for silver nanoplates In 20 mL of a 2.5 mM trisodium citrate aqueous solution, 1 mL of a 0.5 g / L molecular weight 70,000 polystyrene sulfonic acid aqueous solution and 1.2 mL of a 10 mM sodium hydride aqueous solution were added. After the addition, 50 mL of a 0.5 mM silver nitrate aqueous solution was added with stirring at 20 mL / min. The obtained solution was allowed to stand in an incubator (30 ° C.) for 60 minutes to prepare an aqueous dispersion of seed particles of silver nanoplates.

1-1-2. Preparation of Silver Nanoplate Aqueous Dispersion A 4.5 mL of a 10 mM ascorbic acid aqueous solution was added to 200 ml of distilled water, and 12 ml of the above-mentioned aqueous dispersion of silver nanoplate seed particles was added. To the obtained solution, 120 mL of a 0.5 mM silver nitrate aqueous solution was added with stirring at 30 mL / min. After 4 minutes from the completion of the addition of the silver nitrate aqueous solution, stirring was stopped, 20 ml of a 25 mM trisodium citrate aqueous solution was added, and the obtained solution was allowed to stand in an incubator (30 ° C.) under an air atmosphere for 100 hours to silver. A nanoplate aqueous dispersion A was prepared. The optical characteristics of the aqueous dispersion obtained by diluting the prepared dispersion with ultrapure water 5 times are shown in FIG. 1 and Table 1 described later. The wavelength showing the maximum absorption was 454 nm (quenching degree 0.8, half width 56 nm). The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm. When the silver nanoplates in the aqueous dispersion A were observed by SEM, the average particle size of the silver nanoplates was 18 nm, the average thickness was 8 nm, and the aspect ratio was 2.2. A scanning electron microscope SU-70 manufactured by Hitachi, Ltd. was used for the analysis of SEM observation photographs.

1-1-3. Preparation of silver nanoplate water dispersion B Silver nanoplate water dispersion is the same as silver nanoplate water dispersion A except that the amount of water dispersion added to the seed particles of the silver nanoplate is changed from 12 ml to 4 ml. Liquid B was prepared. The optical characteristics of the aqueous dispersion obtained by diluting the prepared dispersion with ultrapure water 5 times are shown in FIG. 2 and Table 2 described later. The wavelength showing the maximum absorption was 482 nm (quenching degree 0.8, half width 72 nm). The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm. When the silver nanoplates in the aqueous dispersion B were observed by SEM, the average particle size of the silver nanoplates was 31 nm, the average thickness was 8 nm, and the aspect ratio was 3.8. A scanning electron microscope SU-70 manufactured by Hitachi, Ltd. was used for the analysis of SEM observation photographs.

1-1-4. Preparation of silver nanoplate aqueous dispersion C Silver nanoplates are prepared in the same manner as the preparation of silver nanoplate aqueous dispersion A, except that the amount of the aqueous dispersion added to the seed particles of the silver nanoplates is changed from 12 ml to 2 ml. An aqueous dispersion C was prepared. The optical characteristics of the aqueous dispersion obtained by diluting the prepared dispersion with ultrapure water 5 times are shown in FIG. 3 and Table 3 described later. The wavelength showing the maximum absorption was 568 nm (quenching degree 0.8, half width 114 nm). The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm. When the silver nanoplates in the aqueous dispersion C were observed by SEM, the average particle size of the silver nanoplates was 50 nm, the average thickness was 10 nm, and the aspect ratio was 5.0. A scanning electron microscope SU-70 manufactured by Hitachi, Ltd. was used for the analysis of SEM observation photographs.

1-1-5. Preparation of Silver Nanoplate Aqueous Dispersion D Add 6.0 mL of 10 mM silver nitrate aqueous solution, 2.5 mL of 24 mM copper nitrate aqueous solution and 2.5 ml of 40 mM dimethylamine borane aqueous solution to 50 ml of 2 mM trisodium citrate aqueous solution for 10 minutes. After stirring, this liquid was placed under light-shielding conditions and allowed to stand at 30 ° C. for 48 hours to obtain an aqueous dispersion of silver particles. The obtained silver particles contained plate-shaped silver particles having an average particle diameter of 90 nm and an average thickness of 15 nm. In addition, silver particles having various shapes such as spherical silver particles and polyhedral silver particles were included as by-produced particles. By centrifuging the obtained aqueous dispersion was carried out to remove by-produced particles. FIG. 4 shows the optical characteristics of the aqueous dispersion obtained by diluting the prepared dispersion with ultrapure water to a volume of 5 times. The wavelength showing the maximum absorption was 800 nm (quenching degree 0.8, half width 248 nm). The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2 Preparation of Toluene Dispersion Solution of Silver Nanoplate 1-2-1. Preparation of Toluene Dispersion E (Example 1) of Silver Nanoplate 12.5 g of Azisper PB824 (acid value: 17, base value: 21) was dissolved in 500 mL of toluene, and 500 mL of silver nanoplate aqueous dispersion A was further dissolved. Added. After stirring, the silver nanoplates were transferred from water into toluene. Then, the toluene layer was extracted to prepare a toluene dispersion E of silver nanoplates. The optical characteristics of the prepared toluene dispersion E diluted with toluene in a 5-fold volume are shown in FIG. 1 and Table 1 below. The wavelength showing the maximum absorption was 484 nm (quenching degree 0.9, half width 64 nm), and the color tone of the dispersion was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-2. Preparation of silver nanoplate toluene dispersion F (Example 2) The same method as for silver nanoplate toluene dispersion E, except that the silver nanoplate aqueous dispersion A was changed to silver nanoplate aqueous dispersion B. , A toluene dispersion F of silver nanoplates was prepared. The optical characteristics of the prepared toluene dispersion F, which is obtained by diluting the prepared toluene dispersion F in a 5-fold volume with toluene, are shown in FIG. 2 and Table 2 described later. The wavelength showing the maximum absorption was 518 nm (quenching degree 0.8, half width 92 nm), and the color tone of the dispersion liquid was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-3. Preparation of silver nanoplate toluene dispersion G (Example 3) The same method as for silver nanoplate toluene dispersion E, except that the silver nanoplate aqueous dispersion A was changed to silver nanoplate aqueous dispersion C. , A toluene dispersion G of silver nanoplates was prepared. The optical characteristics of the prepared toluene dispersion G diluted with toluene in a 5-fold volume are shown in FIG. 3 and Table 3 below. The wavelength showing the maximum absorption was 624 nm (quenching degree 0.8, half width 136 nm), and the color tone of the dispersion liquid was blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-4. Preparation of silver nanoplate toluene dispersion H (Example 4) The same method as for silver nanoplate toluene dispersion E, except that the silver nanoplate aqueous dispersion A was changed to silver nanoplate aqueous dispersion D. , A toluene dispersion H of silver nanoplates was prepared. FIG. 4 shows the optical characteristics of the prepared toluene dispersion H, which is obtained by diluting the prepared toluene dispersion H in a 5-fold volume with toluene. The wavelength showing the maximum absorption was 876 nm (quenching degree 0.8, half width 286 nm), and the color tone of the dispersion liquid was light blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-5. Preparation of Toluene Dispersion Liquid I (Example 5) of Silver Nanoplate Toluene of silver nanoplate except that 12.5 g of Azisper PB824 was changed to 12.5 g of Solspurs 39000 (acid value: 17, basic value: 30). Toluene dispersion I of silver nanoplates was prepared in the same manner as dispersion E. As a result of measuring the optical characteristics of the prepared toluene dispersion I diluted 5 times with toluene, the wavelength showing the maximum absorption was 470 nm (quenching degree 0.9, half width 66 nm), and the dispersion liquid had a wavelength of 470 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-6. Preparation of Toluene Dispersion Liquid J (Example 6) of Silver Nanoplate Toluene dispersion of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of DisperBYK9077 (acid value: 0, base value: 48). Toluene dispersion J of silver nanoplate was prepared by the same method as liquid E. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid J diluted 5 times with toluene, the wavelength showing the maximum absorption was 450 nm (quenching degree 0.9, half width 78 nm), and the dispersion liquid The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-7. Preparation of Toluene Dispersion Liquid K (Example 7) of Silver Nanoplate Toluene dispersion of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of DisperBYK2050 (acid value: 0, base value: 30). A toluene dispersion K of silver nanoplates was prepared in the same manner as in liquid E. As a result of measuring the optical characteristics of the produced toluene dispersion liquid K diluted 5 times with toluene, the wavelength showing the maximum absorption was 472 nm (quenching degree 0.9, half width 110 nm), and the dispersion liquid had a wavelength of 472 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-8. Preparation of Toluene Dispersion L (Example 8) of Silver Nanoplate Toluene of silver nanoplate except that 12.5 g of Azisper PB824 was changed to 12.5 g of Solspurs 13240 (acid value: 0, base value: 91). A toluene dispersion L of silver nanoplates was prepared in the same manner as the dispersion E. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid L diluted 5 times with toluene, the wavelength showing the maximum absorption was 468 nm (quenching degree 0.8, half width 110 nm), and the dispersion liquid had a wavelength of 468 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-9. Preparation of Toluene Dispersion Liquid M (Example 9) of Silver Nanoplate Toluene of silver nanoplate except that 2.55 g of azisper PB824 was changed to 12.5 g of Solspurs 13940 (acid value: 0, base value: 91). A toluene dispersion M of silver nanoplates was prepared in the same manner as the dispersion E. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid M diluted 5 times with toluene, the wavelength showing the maximum absorption was 467 nm (quenching degree 0.8, half width 111 nm), and the dispersion liquid had a wavelength of 467 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-10. Preparation of Toluene Dispersion N (Example 10) of Silver Nanoplate Toluene dispersion of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of DisperBYK145 (acid value: 76, base value: 71). A toluene dispersion N of silver nanoplates was prepared in the same manner as in Liquid E. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid N diluted 5 times with toluene, the wavelength showing the maximum absorption was 466 nm (quenching degree 0.8, half width 62 nm), and the dispersion liquid had a wavelength of 466 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-11. Preparation of Toluene Dispersion Solution O of Silver Nanoplate (Example 11) Toluene of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of azisper PB881 (acid value: 17, basic value: 17). Toluene dispersion O of silver nanoplate was prepared by the same method as dispersion E. As a result of measuring the optical characteristics of the prepared toluene dispersion O diluted with toluene to a 5-fold volume, the wavelength showing the maximum absorption was 480 nm (quenching degree 0.8, half width 73 nm), and the dispersion liquid had a wavelength of 480 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-12. Preparation of Toluene Dispersion P of Silver Nanoplate (Example 12) Toluene of silver nanoplate except that 12.5 g of Azispar PB824 was changed to 12.5 g of Solspurs 24000GR (acid value: 25, base value: 42). A toluene dispersion P of silver nanoplates was prepared in the same manner as the dispersion E. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid P diluted 5 times with toluene, the wavelength showing the maximum absorption was 450 nm (quenching degree 0.8, half width 70 nm), and the dispersion liquid had a wavelength of 450 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-13. Preparation of Toluene Dispersion Liquid Q (Example 13) of Silver Nanoplate Toluene of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of Solspurs 24000SC (acid value: 25, base value: 42). A toluene dispersion Q of silver nanoplates was prepared in the same manner as the dispersion E. As a result of measuring the optical characteristics of the prepared toluene dispersion Q, which was diluted 5 times with toluene, the wavelength showing the maximum absorption was 448 nm (quenching degree 0.8, half width 68 nm), and the dispersion liquid had a wavelength of 448 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-14. Preparation of Toluene Dispersion R (Example 14) of Silver Nanoplate Toluene of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of Solspurs 32000 (acid value: 16, base value: 31). A toluene dispersion R of silver nanoplates was prepared in the same manner as the dispersion E. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid R diluted 5 times with toluene, the wavelength showing the maximum absorption was 470 nm (quenching degree 0.8, half width 96 nm), and the dispersion liquid had a wavelength of 470 nm. The color was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-15. Preparation of Toluene Dispersion Liquid S (Example 15) of Silver Nanoplate Toluene dispersion of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of DisperBYK9077 (acid value: 0, base value: 48). A toluene dispersion S of silver nanoplates was prepared in the same manner as the liquid F. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid S diluted 5 times with toluene, the wavelength showing the maximum absorption was 494 nm (quenching degree 0.8, half width 102 nm), and the dispersion liquid had a wavelength of 494 nm. The color was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-16. Preparation of Toluene Dispersion Liquid T (Example 16) of Silver Nanoplate Toluene of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of Solspurs 24000SC (acid value: 25, base value: 42). A toluene dispersion T of silver nanoplates was prepared in the same manner as the dispersion F. As a result of measuring the optical characteristics of the prepared toluene dispersion liquid T diluted 5 times with toluene, the wavelength showing the maximum absorption was 490 nm (quenching degree 0.8, half width 100 nm), and the dispersion liquid The color was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-17. Preparation of Toluene Dispersion Liquid U (Example 17) of Silver Nanoplate Toluene dispersion of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of DisperBYK9077 (acid value: 0, base value: 48). A toluene dispersion U of silver nanoplates was prepared in the same manner as the liquid G. As a result of measuring the optical characteristics of the prepared toluene dispersion U diluted 5 times with toluene, the wavelength showing the maximum absorption was 590 nm (quenching degree 0.8, half width 145 nm), and the dispersion liquid had a wavelength of 590 nm. The color was blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-18. Preparation of Toluene Dispersion V (Example 18) of Silver Nanoplate Toluene of silver nanoplate except that 12.5 g of Azispar PB824 was changed to 12.5 g of Solspurs 24000SC (acid value: 25, base value: 42). A toluene dispersion V of silver nanoplates was prepared in the same manner as the dispersion G. As a result of measuring the optical characteristics of the prepared toluene dispersion V diluted 5 times with toluene, the wavelength showing the maximum absorption was 596 nm (quenching degree 0.8, half width 147 nm), and the dispersion liquid had a wavelength of 596 nm. The color was blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-2-19. Preparation of Toluene Dispersion W (Comparative Example 1) of Silver Nanoplate Toluene of silver nanoplate except that 12.5 g of azispar PB824 was changed to 12.5 g of azisper PA111 (acid value: 35, base value: 0). An attempt was made to prepare a toluene dispersion W of silver nanoplates by the same method as the dispersion E. However, the silver nanoplates have not been transferred to toluene, and the toluene dispersion W of the silver nanoplates could not be prepared.

1-2-20. Preparation of Toluene Dispersion Liquid X (Comparative Example 2) of Silver Nanoplate Toluene dispersion of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of DisperBYK180 (acid value: 94, base value: 94). An attempt was made to prepare a toluene dispersion liquid X of silver nanoplates by the same method as that of liquid E. However, the silver nanoplates have not been transferred to toluene, and the toluene dispersion liquid X of the silver nanoplates could not be prepared. In addition, metallic luster due to particle growth of silver nanoplates was observed, and it is presumed that the particle size of silver nanoplates changed during the transition from water to toluene.

1-2-21. Preparation of Toluene Dispersion Liquid Y (Comparative Example 3) of Silver Nanoplate Toluene dispersion of silver nanoplate except that 12.5 g of azisper PB824 was changed to 12.5 g of DisperBYK109 (acid value: 0, base value: 140). A toluene dispersion Y of silver nanoplates was prepared in the same manner as the liquid E. However, in the obtained toluene dispersion Y of the silver nanoplate, metallic luster due to the particle growth of the silver nanoplate was observed, and it is speculated that the particle size of the silver nanoplate changed during the transition from water to toluene. Will be done.

1-3 Preparation of propylene glycol monomethyl ether dispersion of silver nanoplate 1-3-1 Preparation of propylene glycol monomethyl ether dispersion Z (Example 19) of silver nanoplate Centrifuge 35 g of toluene dispersion E and silver. The nanoplates and dispersants were precipitated. The obtained precipitate was redispersed in 35 mL of propylene glycol monomethyl ether to prepare a silver nanoplate propylene glycol monomethyl ether dispersion Z. The optical characteristics of the prepared propylene glycol monomethyl ether dispersion Z diluted with propylene glycol monomethyl ether 5 times in volume are shown in FIG. 1 and Table 1 below. The wavelength showing the maximum absorption was 474 nm (quenching degree 0.8, half width 62 nm), and the color tone of the dispersion was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-2 Preparation of propylene glycol monomethyl ether dispersion liquid AA (Example 20) of silver nanoplates The propylene glycol monomethyl ether dispersion liquid Z of silver nanoplates except that the toluene dispersion liquid E was changed to the toluene dispersion liquid J. A propylene glycol monomethyl ether dispersion AA of silver nanoplates was prepared in the same manner as in the above. As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AA diluted 5 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 440 nm (dimming degree 0.8, half). The value width was 66 nm), and the color tone of the dispersion was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-3 Preparation of propylene glycol monomethyl ether dispersion liquid AB (Example 21) of silver nanoplates Except for changing the toluene dispersion liquid E to the toluene dispersion liquid Q, the propylene glycol monomethyl ether dispersion liquid Z of silver nanoplates. A propylene glycol monomethyl ether dispersion AB of silver nanoplates was prepared in the same manner as in the above. As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AB obtained by diluting the prepared propylene glycol monomethyl ether dispersion 5 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 438 nm (dimming degree 0.8, half). The value width was 56 nm), and the color tone of the dispersion was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-4 Preparation of propylene glycol monomethyl ether dispersion AC (Example 22) of silver nanoplates Ppropylene glycol monomethyl ether dispersion Z of silver nanoplates, except that the toluene dispersion E was changed to the toluene dispersion F. A propylene glycol monomethyl ether dispersion AC of silver nanoplates was prepared in the same manner as in the above. The optical characteristics of the produced propylene glycol monomethyl ether dispersion AC diluted 5-fold with propylene glycol monomethyl ether are shown in FIG. 2 and Table 2 below. The wavelength showing the maximum absorption was 506 nm (quenching degree 0.8, half width 86 nm), and the color tone of the dispersion liquid was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-5 Preparation of propylene glycol monomethyl ether dispersion AD (Example 23) of silver nanoplates propylene glycol monomethyl ether dispersion Z of silver nanoplates, except that the toluene dispersion E was changed to the toluene dispersion S. A propylene glycol monomethyl ether dispersion AD of silver nanoplates was prepared in the same manner as in the above. As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AD diluted with propylene glycol monomethyl ether 5 times, the wavelength showing maximum absorption was 492 nm (dimension 0.8, half). The value width was 81 nm), and the color tone of the dispersion was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-6 Preparation of propylene glycol monomethyl ether dispersion AE (Example 24) of silver nanoplates Ppropylene glycol monomethyl ether dispersion Z of silver nanoplates, except that the toluene dispersion E was changed to the toluene dispersion T. A propylene glycol monomethyl ether dispersion AE of silver nanoplates was prepared in the same manner as in the above. As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AE diluted 5 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 498 nm (dimming degree 0.8, half). The price range was 79 nm), and the color tone of the dispersion was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-7 Preparation of propylene glycol monomethyl ether dispersion AF (Example 25) of silver nanoplates Ppropylene glycol monomethyl ether dispersion Z of silver nanoplates, except that the toluene dispersion E was changed to the toluene dispersion G. A propylene glycol monomethyl ether dispersion AF of silver nanoplates was prepared in the same manner as in the above. The optical characteristics of the produced propylene glycol monomethyl ether dispersion AF obtained by diluting the prepared propylene glycol monomethyl ether dispersion AF with propylene glycol monomethyl ether 5 times are shown in FIG. 3 and Table 3 below. The wavelength showing the maximum absorption was 600 nm (quenching degree 0.8, half width 126 nm), and the color tone of the dispersion liquid was blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-8 Preparation of propylene glycol monomethyl ether dispersion AG (Example 26) of silver nanoplates propylene glycol monomethyl ether dispersion Z of silver nanoplates, except that the toluene dispersion E was changed to the toluene dispersion U. A propylene glycol monomethyl ether dispersion AG of silver nanoplates was prepared in the same manner as above. As a result of measuring the optical characteristics of the produced propylene glycol monomethyl ether dispersion AG obtained by diluting the prepared propylene glycol monomethyl ether dispersion AG 5 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 586 nm (dimming degree 0.8, half). The value width was 115 nm), and the color tone of the dispersion was blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-7 Preparation of propylene glycol monomethyl ether dispersion AH (Example 27) of silver nanoplate Except for changing the toluene dispersion E to toluene dispersion V, the propylene glycol monomethyl ether dispersion Z of silver nanoplates Z. A propylene glycol monomethyl ether dispersion AH of silver nanoplates was prepared in the same manner as in the above. As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AH diluted 5 times with propylene glycol monomethyl ether, the wavelength showing maximum absorption was 592 nm (dimension 0.8, half). The price range was 117 nm), and the color tone of the dispersion was blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

1-3-8 Preparation of propylene glycol monomethyl ether dispersion AI (Example 28) of silver nanoplates Ppropylene glycol monomethyl ether dispersion Z of silver nanoplates, except that the toluene dispersion E was changed to the toluene dispersion H. A propylene glycol monomethyl ether dispersion AI of silver nanoplates was prepared in the same manner as in the above method. FIG. 4 shows the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AI, which is obtained by diluting the prepared propylene glycol monomethyl ether dispersion 5-fold with propylene glycol monomethyl ether. The wavelength showing the maximum absorption was 846 nm (quenching degree 0.8, half width 264 nm), and the color tone of the dispersion liquid was light blue. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

2. 2. Preparation of solid composition for preparation of non-aqueous dispersion of silver nanoplate 2-1 Preparation of solid composition AJ (Example 29) for preparation of non-aqueous dispersion of silver nanoplate 12.5 g of Solspurs 24000SC (acid value) : 25, base value: 42) was dissolved in 500 mL of toluene, and 500 mL of silver nanoplate aqueous dispersion A was further added. After stirring, the silver nanoplates were transferred from water into toluene. Then, the toluene layer was extracted to prepare a toluene dispersion of silver nanoplates.
35 g of the prepared toluene dispersion (Solspurs 24000SC) was centrifuged to settle the silver nanoplate and the dispersant. Further, toluene was removed from the obtained precipitate to obtain a solid composition AJ.
The obtained solid composition AJ was redispersed in 35 mL of propylene glycol monomethyl ether to prepare a silver nanoplate propylene glycol monomethyl ether dispersion AJ-1 (Example 29-1). As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AJ-1 diluted 5 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 438 nm (dimming degree 0.8). , Half width 78 nm), and the color tone of the dispersion was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

2-2 Preparation of solid composition AK (Example 30) for preparing a non-aqueous dispersion of silver nanoplates 12.5 g of DisperBYK2050 (acid value: 0, base value: 30) was dissolved in 500 mL of toluene, and further. 500 mL of silver nanoplate aqueous dispersion B was added. After stirring, the silver nanoplates were transferred from water into toluene. Then, the toluene layer was extracted to prepare a toluene dispersion of silver nanoplates.
35 g of the prepared toluene dispersion was centrifuged to settle the silver nanoplate and the dispersant. Further, toluene was removed from the obtained precipitate to obtain a solid composition AK.
The obtained solid composition AK was redispersed in 35 mL of propylene glycol monomethyl ether to prepare a silver nanoplate propylene glycol monomethyl ether dispersion AK-1 (Example 30-1). As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AK-1 diluted 5 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 554 nm (dimming degree 0.8). , Half-value width 114 nm), and the color tone of the dispersion was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

2-3 Preparation of solid composition AL (Example 31) for preparing a non-aqueous dispersion of silver nanoplates 12.5 g of DisperBYK2022 (acid value: 0, base value: 61) was dissolved in 500 mL of toluene, and further. 500 mL of silver nanoplate aqueous dispersion B was added and shaken for 1 minute. After stirring, the silver nanoplates were transferred from water into toluene. Then, the toluene layer was extracted to prepare a toluene dispersion of silver nanoplates.
35 g of the prepared toluene dispersion was centrifuged to settle the silver nanoplate and the dispersant. Further, toluene was removed from the obtained precipitate to obtain a solid composition AL.
The obtained solid composition AL was redispersed in 35 mL of propylene glycol monomethyl ether to prepare a silver nanoplate propylene glycol monomethyl ether dispersion AL-1 (Example 31-1). As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AL-1 diluted 5 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 558 nm (dimension 0.8). , Half-value width 114 nm), and the color tone of the dispersion was red. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

2-4 Preparation of Solid Composition AM (Example 32) for Preparation of Non-Aqueous Dispersion Liquid of Silver Nanoplate 35 g of toluene dispersion liquid E was centrifuged to precipitate the silver nanoplate and the dispersant. Further, toluene was removed from the obtained silver nanoplates to obtain a solid composition AM.
The obtained solid composition AM was dispersed in 1 mL of propylene glycol monomethyl ether to prepare a silver nanoplate propylene glycol monomethyl ether dispersion AM-1 (Example 32-1). As a result of measuring the optical characteristics of the prepared propylene glycol monomethyl ether dispersion AM-1 diluted 700 times with propylene glycol monomethyl ether, the wavelength showing the maximum absorption was 472 nm (dimension 0.8). , Half width 72 nm), and the color tone of the dispersion was yellow. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of an optical path length of 1 cm and a measurement wavelength of 190-1300 nm.

3. 3. Preparation of non-aqueous paint of silver nanoplate 3-1 Preparation of non-aqueous paint of silver nanoplate (propylene glycol monomethyl ether solution) 3-1-1 Non-aqueous paint of silver nanoplate (containing dispersion Z) (Example 33) ), 20 parts by mass of dispersion Z, 100 parts by mass of pentaerythritol triacrylate (PET-30 manufactured by Nippon Kayaku Co., Ltd.), and 3 parts by mass of a photopolymerization initiator (DAROCUR1173, manufactured by BASF), and silver. A nanoplate non-aqueous paint (containing dispersion Z) was prepared.
3-1-2 Preparation of non-aqueous paint (containing dispersion AC) of silver nanoplate (Example 34) Same as non-aqueous paint (containing dispersion Z) except that the dispersion Z was changed to the dispersion AC. By the method, a non-aqueous paint (containing a dispersion liquid AC) of silver nanoplates was prepared.
3-1-3 Preparation of non-aqueous paint (containing dispersion AF) of silver nanoplate (Example 35) Same as non-aqueous paint (containing dispersion Z) except that the dispersion Z was changed to the dispersion AF. By the method, a non-aqueous paint (containing a dispersion liquid AF) of silver nanoplates was prepared.

4. Preparation of silver nanoplate coating film Use a bar coater to apply a non-aqueous paint (containing dispersion Z), a non-aqueous paint (containing dispersion AC), or a non-aqueous paint (containing dispersion AF) to the silver nanoplate. After coating on a glass plate and evaporating the organic solvent, a cured film having a film thickness of 60 μm (coating film Z'(Example 33') is irradiated with light of ^{300 mJ / cm 2 using a high-pressure mercury lamp under air.} , The coating film AC'(Example 34') or the coating film AF'(Example 35')) was prepared. Then, the optical characteristic spectrum of the glass plate having the cured film on the surface was measured. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of measurement wavelength: 190-1300 nm. A glass plate having a coating film Z'(derived from a non-aqueous paint containing a dispersion liquid Z), a coating film AC'(derived from a non-aqueous paint containing a dispersion liquid AC), and a coating film AF'(derived from a non-aqueous paint containing a dispersion liquid AF). The measurement results of the optical characteristic spectrum are shown in FIGS. 1 to 3 and Tables 1 to 3 described later, respectively.

5. Further Example of Non-Aqueous Dispersion of Silver Nanoplate A water-based dispersion of silver nanoplate having a maximum absorption wavelength on the long wavelength side (region of 800 nm to 900 nm) was prepared by a conventional method, and according to the preparation method of Example 1. Non-aqueous dispersion of silver nanoplates using azisper PB822 (acid value: 14, base value: 17) or azisper PB821 (acid value: 17, base value: 9) as a dispersant and toluene as an organic solvent. Liquids (Examples 36 and 37) were prepared. Then, from the non-aqueous dispersion of silver nanoplates using these toluenes as an organic solvent, azisper PB822 or azisper PB821 is used as a dispersant and propylene glycol monomethyl ether is used as an organic solvent according to the production method of Example 19. Non-aqueous dispersions of the silver nanoplates used (Examples 38 and 39) were also prepared.

6. Types of dispersants and dispersion media used in the non-aqueous dispersions of Evaluation Examples 1-28, Examples 29-1 to 2-32-1 and Examples 36 to 39, and Comparative Examples 1 to 3, and the non-aqueous dispersion. The success or failure of the liquid preparation is summarized in Table 4 below. In addition, when a non-aqueous dispersion can be prepared, its maximum absorption wavelength and full width at half maximum are also described.

As can be understood from the results of the above-mentioned examples, when a dispersant having an acid value of 90 or less and a base value of 5 to 100 is used, it is almost the same as that of an aqueous dispersion having a stable dispersed state. A non-aqueous dispersion having the same spectral characteristics could be prepared. Further, FIG. 5 shows the relationship between the maximum absorption wavelength and the full width at half maximum. The plot derived from the examples is as follows:
Half width [nm] = maximum absorption wavelength [nm] x 0.50-157
It was possible to approximate with (solid line in FIG. 5). In addition, each plot is roughly expressed by the following equation:
Half width [nm] = maximum absorption wavelength [nm] x 0.50-157 ± 40
It was within the range of (dashed line in FIG. 5). These half-value width values were similar to those of the corresponding aqueous dispersions, and it was possible to prepare a non-aqueous dispersion with a sharp peak at the maximum absorption wavelength. From this, it was found that by using a dispersant having the above-mentioned characteristics, it is possible to convert from an aqueous dispersion to a non-aqueous dispersion without changing the optical characteristics of the silver nanoplate.
On the other hand, when a dispersant having a base value of less than 5 is used as in Comparative Example 1, the silver nanoplates do not migrate to the organic solvent, and a non-aqueous dispersion of silver nanoplates can be prepared. There wasn't. Then, when a dispersant having an acid value of more than 90 is used as in Comparative Example 2 and when a dispersant having a base value of more than 100 is used as in Comparative Example 3, the particles of the silver nanoplate are used. Metallic luster due to growth was observed. This is because the silver nanoplates aggregated and became bulky during the transition from water to toluene, and it is presumed that the particle size of the silver nanoplates also changed.

Further, as can be understood from the results of Examples 29-1 to 2-1, an aqueous dispersion having a stable dispersed state even when the solid composition of the powdered silver nanoplate is dispersed again in an organic solvent. It was found that a non-aqueous dispersion having almost the same spectral characteristics can be produced. The half-value width was also similar to that of the corresponding aqueous dispersion, and a non-aqueous dispersion with a sharp peak at the maximum absorption wavelength could be prepared. From these facts, it was found that a solid composition for preparing a non-aqueous dispersion of silver nanoplates having excellent redispersibility can be produced by using a dispersant having the above-mentioned characteristics.
In addition, in order to compare the effect of the production method on the non-aqueous dispersion of silver nanoplates, the aqueous dispersion, the dispersion Z of Example 19 in which the dispersion medium was replaced by centrifugation, and the solid composition. FIG. 6 shows the optical characteristics of the dispersion liquid AM-1 of Example 32-1 in which the dispersion medium was replaced through the formation. From this figure, it can be understood that the dispersion liquid Z of Example 19 and the dispersion liquid AM-1 of Example 32-1 have substantially the same spectral characteristics. Therefore, by any method, the silver nanoplate Even in the case of producing a non-aqueous dispersion, a stable non-aqueous dispersion can be produced by using a dispersant having an acid value of 90 or less and a base value of 5 to 100. I understood.
From the above, a dispersant having an acid value of 90 or less and a base value of 5 to 100 is useful for producing a stable non-aqueous dispersion of a metal nanoplate such as a silver nanoplate.

7. Another Example of Non-Aqueous Dispersion of Silver Nanoplate An aqueous dispersion of silver nanoplate having a maximum absorption wavelength on the long wavelength side (region of 900 nm to 1200 nm) was prepared by a conventional method. The particle size of the silver nanoplate having a maximum absorption wavelength of 956 nm was 120 nm, the particle size of the silver nanoplate having a maximum absorption wavelength of 1026 nm was 150 nm, and the particle size of the silver nanoplate having a maximum absorption wavelength of 1140 nm was 180 nm. .. From these aqueous dispersions, silver nano using azisper PB824 as a dispersant and propylene glycol monomethyl ether as an organic solvent according to the preparation methods of Examples 1 and 19 (solvent replacement method from toluene dispersion). Non-aqueous dispersions (Examples 40-42) of plates were prepared.

Further, an aqueous dispersion of silver nanoplates having a maximum absorption wavelength of 505 nm was prepared by a conventional method, and azisper PB824 was used as a dispersant according to the preparation methods of Examples 1 and 19 (solvent replacement method from toluene dispersion). A non-aqueous dispersion of silver nanoplates (Examples 43 to 49) using acetone, methyl ethyl ketone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diacetone alcohol, cyclohexanone, or toluene as an organic solvent was prepared. bottom. (For the toluene dispersion liquid of Example 49, when the toluene dispersion liquid prepared according to the preparation method of Example 1 is replaced with a solvent according to the preparation method of Example 19, toluene is again adopted as the dispersion medium. It was made by

The types of dispersants and dispersion media used in the non-aqueous dispersions of Examples 40 to 49, the success or failure of the preparation of the non-aqueous dispersion, and the maximum absorption wavelength and full width at half maximum thereof are summarized in Table 5 below.

The particle size of the silver nanoplate having the maximum absorption wavelength on the long wavelength side as in Examples 40 to 42 was relatively large, but even such a silver nanoplate is according to the present invention. We were able to prepare a non-aqueous dispersion with good stability. Further, even when different dispersion media were used as in Examples 43 to 49, according to the present invention, a non-aqueous dispersion liquid having good stability could be produced. Since the half-value widths of Examples 40 to 49 are also within the range of the above-mentioned formula (maximum absorption wavelength [nm] × 0.50-157 ± 40), these half-value widths are the corresponding aqueous dispersions. It can be said that a non-aqueous dispersion with a sharp peak at the maximum absorption wavelength could be produced. From these facts, if a dispersant having an acid value of 90 or less and a base value of 5 to 100 is used, silver in the aqueous dispersion is used regardless of the particle size of the silver nanoplate and the type of dispersion medium. It was confirmed that a non-aqueous dispersion can be prepared without changing the optical characteristics of the nanoplate.

8. Relationship between the particle size of the silver nanoplate and its maximum absorption wavelength With respect to the non-aqueous dispersion of the above embodiment, the relationship between the particle size of the silver nanoplate contained therein and its maximum absorption wavelength is shown in FIG. 7 and It is shown in Table 6.

As is clear from FIGS. 7 and 6, there was a positive correlation between the particle size of the silver nanoplate and its maximum absorption wavelength. In particular, in FIG. 7, a linear approximation was possible for the plot of the particle size of the silver nanoplate and its maximum absorption wavelength. From these facts, it was found that the maximum absorption wavelength of the silver nanoplate can be adjusted to a desired region by adjusting the particle size of the silver nanoplate. Specifically, the maximum absorption wavelength of the silver nanoplate is shifted to the long wavelength side by increasing the particle size of the silver nanoplate, or the particle size of the silver nanoplate is decreased to maximize the silver nanoplate. It was found that the absorption wavelength can be shifted to the short wavelength side.

9. Relationship between the Refractive Index of the Dispersion Medium and the Maximum Absorption Wavelength of the Dispersion Solution of Silver Nanoplates The non-aqueous dispersions of Examples 43 to 49 contain the same silver nanoplates but differ only in the dispersion medium. The maximum absorption wavelength is slightly different (Fig. 8). As a result of investigating which characteristic of the dispersion medium corresponds to the change of the maximum absorption wavelength, as shown in FIGS. 9 and 7, between the refractive index of the dispersion medium and the maximum absorption wavelength of the dispersion liquid of the silver nanoplate. Was found to have a positive correlation.

In particular, in FIG. 9, the refractive index of the dispersion medium and the plot of the maximum absorption wavelength of the non-aqueous dispersion of the silver nanoplate could be linearly approximated. From these facts, it was found that the maximum absorption wavelength of the non-aqueous dispersion liquid of the silver nanoplate can be adjusted to a desired region by selecting a dispersion medium having an appropriate refractive index. Specifically, a dispersion medium having a high refractive index is used to shift the maximum absorption wavelength of the non-aqueous dispersion medium of the silver nanoplate to the long wavelength side, or a dispersion medium having a low refractive index is used to shift the silver nano. It was found that the maximum absorption wavelength of the non-aqueous dispersion medium of the plate can be shifted to the short wavelength side.

10. Another Example of Non-Aqueous Paint and Coating on Silver Nanoplates An aqueous dispersion of silver nanoplates having a particle size of 17 nm, 40 nm, or 65 nm was prepared by a conventional method, and the preparation methods of Examples 1 and 19 ( A non-aqueous dispersion (AN, AO, and AP) of silver nanoplates using azisper PB824 as a dispersant and propylene glycol monomethyl ether as an organic solvent was prepared according to the solvent replacement method from a toluene dispersion). bottom. Next, 20 parts by mass of any of the above non-aqueous dispersions, 10 parts by mass of pentaerythritol triacrylate (PET-30 manufactured by Nippon Kayaku Co., Ltd.), and 0. 3 parts by mass were mixed to prepare a non-aqueous coating material (containing dispersion AN, AO, or AP) of silver nanoplates (Examples 50 to 52).

Non-water-based paint (containing dispersion AN), non-water-based paint (containing dispersion AO), or non-water-based paint (containing dispersion AP) of silver nanoplates are each applied to a glass plate using a spin coater and organic. After evaporating the solvent, a high-pressure mercury lamp is used ^{to irradiate light of 300 mJ / cm 2} under air to obtain a cured film having a thickness of 6 μm (coating film AN'(Example 50'), coating film AO'(implementation). Example 51') or coating film AP'(Example 52')) was prepared. Then, the optical characteristic spectrum of the glass plate having the cured film on the surface was measured. The optical characteristics were measured using an ultraviolet-visible near-infrared spectrophotometer MPC3100UV-3100PC manufactured by Shimadzu Corporation under the conditions of measurement wavelength: 190-1300 nm. The measurement results of the optical characteristic spectrum of the glass plate having the coating film AN'(Example 50'), the coating film AO'(Example 51'), or the coating film AP'(Example 52') are shown in FIGS. 10 and Table. Shown in 8.

As can be understood from the above examples, according to the present invention, if a dispersant having an acid value of 90 or less and a basic value of 5 to 100 is used, a metal nanoplate such as a silver nanoplate can be used. Since a non-aqueous dispersion can be produced without changing the optical characteristics of the metal nanoplate in the aqueous dispersion regardless of the particle size or the type of dispersion medium, the metal nanoplate having various maximum absorption wavelengths can be produced. Non-aqueous paints and coatings can be produced. Further, according to the present invention, the maximum absorption wavelength can be easily adjusted by adjusting the particle size of the metal nanoplate such as the silver nanoplate, so that the metal nanoplate showing various color tones can be adjusted. Non-aqueous paints and coatings can be provided. Further, according to the present invention, by adopting a dispersion medium having a different refractive index as the dispersion medium of the metal nanoplate, the maximum absorption wavelength of the dispersion liquid of the metal nanoplate can be easily adjusted.

Claims (15)

A non-aqueous dispersion of metal nanoplates containing a dispersant and an organic solvent.
The acid value of the dispersing agent is 90 or less, the base number of the previous SL dispersing agent is 5 to 100, the ratio acid number of base number of the dispersant is, acid value / base value = 2.0 The weight average molecular weight Mw of the dispersant is 10,000 or more.
A non-aqueous dispersion liquid containing no heterocyclic compound containing at least one sulfur atom. The non-aqueous dispersion according to claim 1, wherein the metal is gold or silver. The non-aqueous dispersion according to claim 1 or 2 , wherein the solubility parameter (SP value) of the organic solvent is 8 to 12. The non-aqueous dispersion according to any one of claims 1 to 3 , wherein the organic solvent contains at least one selected from the group consisting of aromatic hydrocarbons, ketones, esters and ethers. A solid composition containing a dispersant and a metal nanoplate for preparing a non-aqueous dispersion of a metal nanoplate.
The acid value of the dispersing agent is 90 or less, the base number of the previous SL dispersing agent is 5 to 100, the ratio acid number of base number of the dispersant is, acid value / base value = 2.0 The weight average molecular weight Mw of the dispersant is 10,000 or more.
A solid composition free of heterocyclic compounds containing at least one sulfur atom. A non-aqueous coating material for metal nanoplates, which comprises the non-aqueous dispersion liquid according to any one of claims 1 to 4 and a binder. A coating film of a metal nanoplate formed from the non-aqueous dispersion liquid according to any one of claims 1 to 4 or the non-aqueous paint according to claim 6. The non-aqueous dispersion liquid according to any one of claims 1 to 4 , which is used for a member that controls light, a member that utilizes electrical characteristics, or a sensor-related member. The non-aqueous paint according to claim 6 , for use in a member that controls light, a member that utilizes electrical characteristics, or a member related to a sensor. The coating film according to claim 7 , for use in a member that controls light, a member that utilizes electrical characteristics, or a member related to a sensor. The non-aqueous dispersion according to any one of claims 1 to 4 and 8 , the solid composition according to claim 5, the non-aqueous paint according to claim 6 or 9 , or claim 7 or 10 . A method of adjusting the maximum absorption wavelength of the metal nanoplates used in the described coatings.
The step of increasing the particle size of the metal nanoplate to shift the maximum absorption wavelength of the metal nanoplate to the longer wavelength side, or decreasing the particle size of the metal nanoplate to maximize the absorption of the metal nanoplate. A method comprising the step of shifting the wavelength to the short wavelength side. The step of increasing or decreasing the particle size is a step of preparing a metal nanoplate having a particle size of about 10 nm to about 30 nm and adjusting the maximum absorption wavelength of the metal nanoplate to about 420 nm to about 530 nm. A step of preparing a metal nanoplate of 30 nm to about 50 nm and adjusting the maximum absorption wavelength of the metal nanoplate to about 470 nm to about 640 nm, or preparing a metal nanoplate having a particle size of about 50 nm to about 200 nm. The method according to claim 11 , further comprising the step of adjusting the maximum absorption wavelength of the metal nanoplate to about 520 nm to about 1350 nm. A method for adjusting the maximum absorption wavelength of a non-aqueous dispersion of a metal nanoplate containing a dispersant and an organic solvent.
A step of substituting at least a part of the organic solvent (first organic solvent) in the non-aqueous dispersion liquid with a second organic solvent, or an organic solvent (first organic solvent) in the non-aqueous dispersion liquid. Including the step of adding a second organic solvent,
In the replacement step or the addition step, a liquid having a higher refractive index than the first organic solvent is adopted as the second organic solvent, and the maximum absorption wavelength of the non-aqueous dispersion liquid is used as the dispersion medium. A step of shifting to a longer wavelength side than the maximum absorption wavelength of the non-aqueous dispersion liquid containing only the organic solvent of the above, or adopting a liquid having a refractive index lower than that of the first organic solvent as the second organic solvent. The step of shifting the maximum absorption wavelength of the non-aqueous dispersion liquid to a shorter wavelength side than the maximum absorption wavelength of the non-aqueous dispersion liquid containing only the first organic solvent as a dispersion medium is included.
A method in which the acid value of the dispersant is 90 or less and the base value of the dispersant is 5 to 100. It is a method of adjusting the maximum absorption wavelength of the dispersion liquid of the metal nanoplate containing the first dispersion medium.
A step of replacing at least a part of the first dispersion medium with a second dispersion medium, or a step of adding a second dispersion medium to the first dispersion medium is included.
The replacement step or the addition step employs a liquid having a higher refractive index than the first dispersion medium as the second dispersion medium, and uses the maximum absorption wavelength of the dispersion as the first dispersion medium as the dispersion medium. The step of shifting to a longer wavelength side than the maximum absorption wavelength of the dispersion liquid containing only, or by adopting a liquid having a refractive index lower than that of the first dispersion medium as the second dispersion medium, the dispersion liquid A method comprising a step of shifting the maximum absorption wavelength to a shorter wavelength side than the maximum absorption wavelength of a dispersion liquid containing only the first dispersion medium as the dispersion medium. The method for preparing a non-aqueous dispersion according to any one of claims 1 to 4 and 8.
The metal nanoplate is dispersed in an organic solvent having a refractive index higher than that of water, and the maximum absorption wavelength of the non-aqueous dispersion is shifted to a longer wavelength side than the maximum absorption wavelength of the aqueous dispersion of the metal nanoplate. The maximum absorption wavelength of the non-aqueous dispersion liquid is shifted to a shorter wavelength side than the maximum absorption wavelength of the water dispersion liquid of the metal nanoplate by dispersing in an organic solvent having a refractive index lower than that of water. A method comprising steps.

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