Aqueous dispersion of structurally color-developing fine particles

Abstract

To provide an aqueous dispersoid optimal for giving a structure that has excellent film-forming properties, can show structural coloration in a short drying time, and allows easy charging of a binder component or the like between fine particles.SOLUTION: An aqueous dispersoid contains fine particles and a water-soluble resin. The fine particles have a number average particle size of 50-450 nm and a number-based particle size CV value of 10% or less. Relative to 100 pts.mass of the fine particles, the content of the water-soluble resin is 0.001-0.4 pt.mass.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous dispersion of microparticles that exhibit structural color, and a structure in which the microparticles are arranged to exhibit structural color.

Background Art

[0002] Structural color refers to a color development phenomenon caused by a fine structure equal to or smaller than the wavelength of light. Examples of common structural colors include compact discs, soap bubbles, Morpho butterflies, and jewel beetles. In these examples, although they are not colored themselves, they appear colored because light is interfered by their fine structure. In recent years, development has been underway to artificially create a regular periodic structure that exhibits structural color. For example, using a dispersion in which monodisperse microparticles are dispersed in a medium, and arranging, aligning, drying, and fixing the microparticles by pouring, spraying, coating, flowing, etc., various methods have been proposed for manufacturing a structure in which the microparticles are regularly arranged in a planar direction on a substrate. As such, a colloidal crystal is known as a regular arrangement of such microparticles, and it is known that such a colloidal crystal exhibits Bragg reflection and structural color. In addition, research and development have been carried out on applying this to color materials and infrared reflection films.

[0003] As a method of forming a colloidal crystal to exhibit structural color, in Patent Document 1, a method has been proposed for forming a colloidal crystal at low cost only by coating, using core-shell particles composed of a core part and a shell part, and utilizing the fluidity of the shell part that fuses by heating. Also, in Patent Document 2, a water-soluble resin having a hydrogel ability such as carboxymethyl cellulose sodium is added to a dispersion of organic polymer particles at a ratio of 100 parts by mass of the organic polymer particles. ​​​​​​​​​​​ A method has been proposed in which a film exhibiting structural color is formed by incorporating 0.5 to 2.2 parts by mass of the substance. It is being done. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-249517 [Patent Document 2] Japanese Patent Publication No. 2016-187803 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the method proposed in Patent Document 1 involves heating for forming colloidal crystals. There was a problem with long processing times. Furthermore, the method proposed in Patent Document 2 does not produce sufficient structural color, and when forming a film... One problem was the long drying time for the eyes.

[0006] The objective of the present invention is to solve the above problems. That is, to have excellent film-forming properties and short drying time It is possible to exhibit structural color between particles, and furthermore, binder components can be easily filled between the fine particles. The objective is to provide an optimal aqueous dispersion for obtaining a structure that can be filled. [Means for solving the problem]

[0007] The inventors, after diligent research to solve the above problem, have found that a specific water-soluble resin can be added to fine particles. We discovered the importance of incorporating a specific amount of fat, which led to the present invention.

[0008] In other words, the present invention has the following features. [1] An aqueous dispersion containing fine particles and a water-soluble resin, The number average particle diameter of the fine particles is 50 to 450 nm, and the CV value of the particle diameter based on the number standard is 10 % or less, and the aqueous dispersion contains 0.001 to 0.4 parts by mass of the water-soluble resin with respect to 100 parts by mass of the fine particles. Aqueous dispersion. [2] The aqueous dispersion according to [1], wherein the contact angle with respect to the polyester film is 2° or more lower than the contact angle of water with respect to the polyester film. [[ID=X]] [3] The aqueous dispersion according to [1] or [2], wherein the concentration of the solid content is 10% by mass or more. [4] The aqueous dispersion according to any one of [1] to [3], wherein the water-soluble resin is an ionic water-soluble resin. Aqueous dispersion. [5] The aqueous dispersion according to any one of [1] to [4], wherein the water-soluble resin is an ionic polyvinyl alcohol-based resin. JAqueous dispersion.

[0009] [6] A structure in which the fine particles described in any one of [X] to [5] are arranged to develop color. [7] Further, the structure according to [6], which has an overcoat layer on the surface. [8] An aqueous dispersion containing fine particles that exhibit structural color when arranged and a water-soluble resin, , and the aqueous dispersion contains 0.001 to 0.4 parts by mass of the water-soluble resin with respect to 100 parts by mass of the fine particles. Aqueous dispersion. [9] The aqueous dispersion according to [8], wherein the contact angle with respect to the polyester film is 2° or more lower than the contact angle of water with respect to the polyester film. Aqueous dispersion.

[10] The aqueous dispersion according to [8] or [9], wherein the concentration of the solid content is 10% by mass or more. .

[0010]

[11] The aqueous dispersion according to any one of [8] to

[10] , wherein the water-soluble resin is an ionic water-soluble resin. Aqueous dispersion.

[12] The aqueous dispersion according to [8] to It should be noted that there seems to be an incomplete number in "

[12] The aqueous dispersion according to [8] to ". Please check and correct if necessary. Also, the reference numbers in the original text seem a bit inconsistent in some parts (e.g., the sudden appearance of "[X]" in "[6] A structure in which the fine particles described in any one of [X] to [5] are arranged to develop color."), which might need to be clarified for a more accurate translation.

[0011] The aqueous dispersion according to any one of them.

[13] A structure in which the fine particles described in any one of [8] to

[12] are arranged to develop color.

[14] Further, the structure according to

[13] , which has an overcoat layer on the surface.

[15] Using the aqueous dispersion according to any one of [1] to [5] or [8] to

[12] Paint composition.

[0011]

[16] Using the aqueous dispersion according to any one of [1] to [5] or [8] to

[12] Ink composition.

[17] Using the aqueous dispersion according to any one of [1] to [5] or [8] to

[12] Cosmetics.

[18] Using the aqueous dispersion according to any one of [1] to [5] or [8] to

[12] Decorative film.

[19] Using the aqueous dispersion according to any one of [1] to [5] or [8] to

[12] Optical material.

[20] A paint composition using the structure described in [6], [7],

[13] or

[14] .

[0012]

[21] An ink composition using the structure described in [6], [​​​​​​​​​​​​​​​​​​​​The structure of the present invention exhibits good structural coloration because the film surface is uniform. Binder components and other substances can be easily filled in between. [Modes for carrying out the invention]

[0014] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is for illustrative purposes only. This is an example (representative example) of an embodiment of the invention, and unless the present invention exceeds its gist, it contains the following: Not limited to this. Furthermore, when the expression "~" is used in this specification, the numbers before and after it are... The term "rui" will be used in a sense that includes physical values. Also, the numerical values ​​listed as upper and lower limits... The term "physical value" should be used in a sense that includes that value.

[0015] The aqueous dispersion of the present invention contains fine particles and a water-soluble resin.

[0016] [Fine particles] The fine particles of the present invention have a number-average particle diameter of 50 to 450 nm, and a CV of particle diameter based on the number of particles. The value should be 10% or less. If the number-average particle size and the CV value of the particle size based on the number are within the above range, There are no particular restrictions; the particles may be organic or inorganic.

[0017] Among organic and inorganic microparticles, it is easier to precisely control reaction conditions such as composition, and the size is large. Organic microparticles are preferred because they make it easier to obtain microparticles with a uniform pod shape.

[0018] [Number-average particle size] The number-average particle size of the fine particles of the present invention is 50 to 450 nm. If the number-average particle size is within the above range, it is preferable because it results in good structural color development. The method for measuring the number-average particle size of the present invention is as described in the examples.

[0019] [CV value of particle size based on number of particles] The coefficient of variation (CV) of the particle size based on the number of particles in the present invention is 10% or less. The CV value is also called the "coefficient of variation" or "relative standard deviation," and in this invention, (standard deviation / It is calculated as (average particle size by number) × 100. If the CV value of the particle size based on the number of particles is within the above range, then the structural color development will be good. That is preferable. The method for measuring the CV value of particle size based on the number of particles according to the present invention is as described in the examples.

[0020] [Organic fine particles] The organic microparticles of this invention refer to microparticles made of a general polymer. Common polymers include, for example, polyamides, polyimides, and low-density polyethylene. , high-density polyethylene, poly(meth)acrylic acid esters, polystyrene and its derivatives Examples include polystyrenes, polyvinyl chlorides, phenolic resins, and polycarbonates used in bodies and other applications. It can be done.

[0021] Among these, the raw materials are readily available, and it is possible to produce fine particles with uniform particle size. Because they are easy to use, poly(meth)acrylic acid esters and polystyrenes are preferred, and they have high flexural properties. Polystyrenes are more preferred because they yield polymers with a high degree of foldability. High refractive index polymers have a large difference in refractive index between the inside and outside of the particles, which improves structural coloration. That is preferable. The organic microparticles may be non-crosslinked polymers or crosslinked polymers.

[0022] In order to achieve the effects of the present invention, the organic microparticles of this invention must have a uniform particle size. That is the case. To obtain organic fine particles with uniform particle size, methods such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization can be used. A polymer of an appropriate size is obtained by polymerization, etc., and this is pulverized to make a fine powder, and then granulated by operations such as sieving. There are methods to standardize particle size. Additionally, soap-free emulsion polymerization can produce organic microparticles with uniform particle size. There is a way to obtain particles directly. Among these methods, the soap-free emulsion polymerization method is preferred due to its superior productivity. stomach.

[0023] [Poly(meth)acrylic acid esters] The poly(meth)acrylic acid esters of the present invention are defined as having (meth)acrylic acid ester units. It is a polymer whose main component is (meth)acrylic acid. Here, the main component is (meth)acrylic acid relative to the entire polymer. This indicates that the ester unit content is 50% by mass or more, and more specifically, 60% by mass or more.

[0024] As for (meth)acrylic acid esters that serve as raw materials for (meth)acrylic acid ester units, For example, methyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate Examples include ropil and butyl (meth)acrylate.

[0025] Poly(meth)acrylic acid esters can be either random copolymers or block copolymers. However, it is generally a random copolymer. Poly(meth)acrylic acid esters include, in addition to the (meth)acrylic acid esters mentioned above, The monomers may be copolymerized.

[0026] Examples of arbitrary monomers include styrenes such as styrene and methylstyrene; styrene Metal salts of sulfonic acids such as sodium salts; acidic monomers such as acrylic acid and methacrylic acid; acrylic acid Examples include acrylamides such as lylamide and N-propylacrylamide. Among these, sodium styrene sulfonic acid is chosen because it allows for good control of particle size. Metal salts, such as salts, are preferred. Furthermore, when introducing a crosslinking structure to poly(meth)acrylic acid esters, known multi-functional The monomers can be copolymerized.

[0027] [Polystyrenes] The polystyrenes of this invention are polymers whose main component is styrene units. This refers to a polymer where the styrene unit content is 50% by mass or more, and more specifically, 60% by mass. This indicates that the value is greater than or equal to the stated value. Polystyrenes may be in the form of random copolymers or block copolymers, but generally they are It is a dam copolymer. Polystyrenes may be copolymerized with any monomer other than styrene.

[0028] Any monomer could be, for example, methylstyrene, chlorostyrene, or other monomers besides styrene. Styrenees; metal salts such as sodium styrene sulfonic acid; acrylic acid, methacrylic acid Acidic monomers such as (meth)acrylate; (meth)acrylate such as methyl (meth)acrylate and ethyl (meth)acrylate. Acrylic acid esters; acrylamides such as acrylamide and N-propylacrylamide. Examples include: Among these, sodium styrene sulfonic acid is chosen because it allows for good control of particle size. Metal salts, such as salts, are preferred. Furthermore, when introducing a crosslinked structure to polystyrenes, known polyfunctional monomers are copolymerized. That's all you need to do.

[0029] [Composition of polystyrene compounds] Polystyrenes preferably contain 80.0 to 99.75% by mass of styrene units. i. If the styrene unit content is within the above range, the refractive index of the particles will increase, and structural color development will be This is desirable because it improves [the condition]. A styrene unit content of 90.0% by mass or more is more preferable. Also, 99.4% by mass or more is preferable. The bottom one is preferable.

[0030] Polystyrenes contain acidic monomer units such as acrylic acid units and methacrylic acid units at a rate of 0.25 It is preferable to contain ~20.0% by mass. If the content of acidic monomer units is within the above range This is preferable because it reduces cullet during polymerization. A content of acidic monomer units of 0.6% by mass or more is more preferable. Also, 10.0% by mass or more is preferable. The bottom one is preferable.

[0031] Polystyrenes are any monomer units other than the acidic monomer units and / or polyfunctional monomers If body units are present, their content is preferably 3% by mass or less, and more preferably 2% by mass or less. It's nice. If the aforementioned content is 3% by mass or less, the particle size can be controlled well.

[0032] [Method for producing organic microparticles] The organic fine particles of the present invention are preferably obtained by soap-free emulsion polymerization. Emulsion polymerization is a known polymerization method, for example, as follows: Deionized water is placed in the reaction vessel, and polymerization aids are added while heating and stirring as needed. First, thoroughly disperse the polymerization aid in deionized water. Next, add the polymerization initiator while continuing to stir. Then, while continuing to stir, the monomers are added dropwise to initiate the polymerization reaction. Particles are formed according to the rows.

[0033] The solid content concentration during polymerization, i.e., the concentration of organic fine particles relative to the entire system during polymerization, is 20-40%. Amount in percent is preferred. If the solid content concentration during polymerization is above the aforementioned lower limit, the productivity of organic fine particles will improve. Furthermore, If the value is below the aforementioned upper limit, there will be no generation of cullet during polymerization or deposits on the inner walls of the polymerization apparatus, etc. When a polymerization initiator is used, the polymerization temperature is generally set to 60-90°C. Afterward, the organic microparticles are extracted as an emulsion.

[0034] Examples of polymerization initiators used in soap-free emulsion polymerization include sodium persulfate and persulfate. Water-soluble polymerization initiators such as potassium acid and ammonium persulfate; benzoyl peroxide, lauryl peroxide - Oil-soluble polymerization initiators such as oxides; redox systems formed by combinations of oxidizing and reducing agents. Polymerization initiators are one example. These may be used individually or in combination of two or more types. Among these, water-soluble polymerization initiators are preferred due to their ease of handling.

[0035] [Inorganic fine particles] The inorganic fine particles of the present invention are metal particles or metal oxides. Among these, silica nanoparticles are preferred because they are readily available and have excellent permeability. It seems so.

[0036] [Water-soluble resin] The water-soluble resin of the present invention is a polymer compound that dissolves in water or at least disperses in water. It is a substance. Water-soluble resins contain ionic groups such as sulfonyl groups and carboxyl groups; water-soluble groups such as hydroxyl groups within the molecule. It has soluble substituents and is soluble in water. In the aqueous dispersion of the present invention, the water-soluble resin enables the formation of a uniform coating film. .

[0037] Water-soluble resins include nonionic water-soluble resins and ionic water-soluble resins. Examples of nonionic water-soluble resins include water-soluble polyacrylamide and water-soluble acrylic. Polyvinyl alcohol-based resins, nonionic polyvinyl alcohol-based resins, polyvinylpyrrolidone, polyethylene Lenyl oxides, polyvinyl acetate; natural polymer compounds such as starch, gelatin, and casein. These are some examples. Examples of ionic water-soluble resins include water-soluble polyester resins and polyacrylic acid. Examples include ionic polyvinyl alcohol-based resins and carboxymethylcellulose.

[0038] Among these, nonionic polyvinyl axylamide is chosen because of its high hydrolysis resistance in the polymer main chain. It is preferable to use an alcohol-based resin and / or an ionic polyvinyl alcohol-based resin. stomach. Furthermore, among water-soluble resins, ionic water-soluble resins have improved ionic strength. preferable.

[0039] [Ionic water-soluble resin] Ionic water-soluble resins are water-soluble resins that have anionic or cationic parts. And so, specifically as described above. Among ionic water-soluble resins, ionic polyvinyl chloride is chosen because of its excellent solvent resistance. Alcohol-based resins are preferred.

[0040] [Ionic polyvinyl alcohol-based resin] Ionic polyvinyl alcohol-based resins are those containing sulfonyl groups or their salts in their molecular chains. Carboxyl groups or their salts; polyvinyl alcohol containing ionic groups such as quaternary ammonium salts. It is a rubbing resin.

[0041] Specifically, as an ionic polyvinyl alcohol-based resin, the molecular chain contains sulfonyl groups A polyvinyl alcohol-based resin containing sodium salts, with carboxyl groups in the molecular chain. Examples include polyvinyl alcohol-based resins containing um salts. Among these, the sodium salt of the sulfonyl group is included because the salt dissociates easily. Polyvinyl alcohol-based resins are preferred.

[0042] Examples of commercially available ionic polyvinyl alcohol-based resins include, for example, Gosenex. Examples include a specially modified polyvinyl alcohol-based resin manufactured by Mitsubishi Chemical Corporation.

[0043] [Aqueous dispersion] The aqueous dispersion of the present invention contains the fine particles and the water-soluble resin. Here the aqueous dispersion This means that fine particles and water-soluble resin are dispersed in a water-based medium. A water-based medium is one in which the proportion of water is 50% by mass or more, and more specifically, 60% by mass or more. This represents the following. Any organic solvent soluble in water can be selected as a component other than water.

[0044] The water-soluble resin content is 0.001 to 0.4 parts by mass per 100 parts by mass of fine particles. . The preferred content of water-soluble resin is 0.005 to 0.4 parts by mass per 100 parts by mass of fine particles. Parts by mass are more preferably 0.01 to 0.4 parts by mass, and even more preferably 0.05 to 0.4 parts by mass. stomach. If the water-soluble resin content is within the above range, film-forming properties will be good.

[0045] [concentration] The concentration of solids in the aqueous dispersion is 10% by mass or more. The concentration of solids in the aqueous dispersion is preferably 20% by mass or more, and more preferably 25% by mass or more. Furthermore, the upper limit of the solid content concentration of the aqueous dispersion is preferably 60% by mass or less, and 50% by mass or less. The bottom one is preferable. If the solid content concentration of the aqueous dispersion is within the above range, film-forming properties will be good, and the resulting structure will be The structural coloration is excellent. The method for measuring the solid content of the present invention is as described in the examples.

[0046] [Contact angle] The aqueous dispersion of the present invention has a contact angle with the polyester film. It is characterized by being 2° or more lower than the contact angle of water with respect to the material. The contact angle of the aqueous dispersion with respect to the polyester film is It is preferable that the contact angle is 2° or lower than the contact angle of water, and more preferably 3° or lower. Furthermore, the upper limit for the contact angle difference is 20°.

[0047] Here, polyester film refers to a film made of polyethylene terephthalate resin. Surface treatments such as plasma treatment have been applied as needed. Here, "water" refers to deionized water. The method for measuring the contact angle of the present invention is as described in the examples.

[0048] [Structural color development] The fine particles of the present invention have structural coloration properties. Structural coloration refers to the regularity of fine particles with uniform particle sizes. This means that structural color is expressed when the elements are arranged in a specific way. Structural coloration refers to the fact that the crystalline structure, in which the fine particles are arranged in a regular pattern, is affected by the wavelength of light. This refers to the phenomenon where optical physical phenomena such as interference and scattering occur, causing colors to appear.

[0049] Structural coloration is due to the properties of light, so it is not limited to the visible light region, but also the ultraviolet region and red light. This phenomenon also occurs in the extra-radiation region. To exhibit structural color in the ultraviolet region, it is sufficient to use fine particles with a small number-average particle size. To produce structural color in the infrared region, it is best to use fine particles with a large number-average particle size. . In this invention, structural coloration is used to improve the design of articles, and therefore in the visible light region It is preferable to exhibit structural coloration.

[0050] Here, the visible light region refers to wavelengths of 360-830 nm, and the ultraviolet region refers to wavelengths of 200-3 This represents 59nm, and the infrared region refers to wavelengths of 831-2500nm.

[0051] [Structure and its manufacturing method] The structure of the present invention is characterized by the periodic arrangement of the fine particles, which exhibit structural coloration. Here, "arrangement" refers to the formation of colloidal crystals by fine particles, or colloidal amorphous particles. This refers to the formation of a crystalline structure. Materials that exhibit structural color are those in which fine particles of uniform size are regularly arranged, causing diffraction and interference of light. This refers to objects that exhibit angle-dependent coloration, where the color changes depending on the viewing angle.

[0052] The aqueous dispersion of the present invention contains a water-soluble resin. When fine particles are arranged, the water-soluble resin The lipids reduce the surface tension of the aqueous dispersion, improving film-forming properties while maintaining high structural color development. It is thought to produce an effect that causes this. As a result, the structure obtained using the aqueous dispersion of the present invention is an aqueous structure that does not contain a water-soluble resin. The structure obtained using the dispersion exhibits good film-forming properties.

[0053] A method for manufacturing the structure of the present invention is, for example, as follows. An appropriate amount of water-soluble resin is added to the emulsion of fine particles obtained by soap-free emulsion polymerization. Dilute this as needed. Apply this to a smooth substrate. Then, dry it at an appropriate temperature. , obtain the structure.

[0054] Because the fine particles of the present invention have uniform particle sizes, they form colloids when arranged periodically. It has the characteristic of crystallizing and exhibiting structural coloration.

[0055] The structure of the present invention is characterized by the periodic arrangement of the fine particles, which exhibit structural coloration. Examples of structures include objects in which fine particles are arranged on a substrate, and objects in which fine particles are arranged on a substrate. Examples include materials from which colloidal crystals have been detached without damaging the periodic arrangement of fine particles. The base material is not particularly limited and can be any common material such as metal, resin, wood, or paper. It is possible to use this. For surface protection purposes, an overcoat layer may be provided on the surface of the structure as needed.

[0056] When a film-like material is used as the base material, the resulting structure will be film-like. For film-like structures, an overcoat layer may be applied to the surface as needed for surface protection. It may be established.

[0057] [Overcoat layer] The overcoat layer is a layer that protects the surface of the structure, forming a film on the surface of the structure. The materials used are not particularly limited, as long as they are suitable for that purpose. The overcoat layer not only covers the surface of the microparticles but also fills the spaces between them. It is preferable. Examples of resins that make up the overcoat layer include acrylic resin and acrylic urethane. Examples include resins, silicone resins, and epoxy resins. The resin can be in the form of a resin solution diluted with any solvent, or an emulsion dispersed in water. "Yon" is the more common form.

[0058] The thickness of the overcoat layer is not particularly limited, and it covers the fine particles of the structure. It just needs to be thicker than that. The overcoat layer is applied as a thin film of the resin solution or emulsion onto the structure, and if necessary... Depending on the circumstances, heat treatment or other processes can be applied to form it on the surface of the structure.

[0059] [Application] The aqueous dispersion of the present invention exhibits excellent wettability to the substrate to be coated, and the high viscosity component contained in the dispersion medium Because it is present in small quantities, it does not inhibit the arrangement of fine particles and exhibits excellent film-forming properties. The structure of the present invention is Because the film surface is uniform, structural color development is good. Also, binders can easily form between the fine particles. It can be filled with ingredients, etc. Based on these characteristics, the aqueous dispersion of the present invention can be used alone or as a secondary processing material, for example, in construction... Paint compositions such as building paints, automotive paints, and plastic paints; inkjet recording Ink compositions such as inks, gravure printing inks, and stationery inks; foundations, lipsticks Cosmetics such as lip balm, blush, eyebrow cosmetics, and nail polish; color sheets, etc. Decorative films such as decorative films; reflective displays, color change sensors, anti-counterfeiting agents, electrodeposition It is suitably used in optical materials such as color plates, color filters, and polarizing films.

[0060] Furthermore, the structure of the present invention can be used alone or as a secondary processed material in applications such as architectural paints and automobiles. Paint compositions such as paints for general use and paints for plastics; inkjet recording inks, gravure printing inks. Ink compositions such as inks for printing and stationery; foundations, lipsticks, lip balms. Cosmetics such as blush, eyebrow cosmetics, and nail polish; decorative sheets, decorative films, etc. Decorative films; reflective displays, color change sensors, anti-counterfeiting agents, electrodeposited color boards, color It is suitably used in optical materials such as filters and polarizing films.

[0061] In the various applications described above, the aqueous dispersion of the present invention may be used as a direct raw material. Furthermore, using a structure in which fine particles are arranged as a raw material, while maintaining the state in which the fine particles are arranged, It may also be used by dispersing it in a matrix material. [Examples]

[0062] The present invention will be described in more detail below with reference to examples, but the present invention will not exceed its essence. The following examples are not the only ones that may be included. In the following description, "parts" and "%" refer to "parts by mass" and "% by mass," respectively. show. In the following examples and comparative examples, various physical properties were measured by the methods described below.

[0063] [Evaluation Method] (1) Number-average particle size After coating a substrate with a fine particle emulsion and drying it, the image is taken using an electron microscope with a magnification of 20,000x or more. Then, images of the microparticles were observed. The diameter of at least 400 microparticles in the images was measured, and this The number-average particle size was obtained by taking the arithmetic mean of the values.

[0064] (2) CV value of particle size Using the above measurements of the diameter of at least 400 particles, (standard deviation / average particle diameter) The calculation was multiplied by 100 to determine the CV value of the particle size based on the number of particles.

[0065] (3) Solid content concentration The solid content concentration of the emulsion was measured using a heat-drying type moisture meter MX manufactured by A&D Co., Ltd. Using -50, heat 10g of emulsion at 190°C for 60 minutes to evaporate the water. This was determined by [method / method].

[0066] (4) Difference in contact angle The contact angle was determined as follows: A polyester film treated with plasma using DM-300 manufactured by Kyowa Interface Science. (Toray Films, Lumirror (black), 100 μm thick) on which 2 μL of aqueous dispersion liquid A droplet was prepared, and the contact angle was measured at two points 60 seconds after droplet placement in an environment of 25°C and 60% RH, and the average was taken. The value was calculated. Furthermore, the contact angle of deionized water was measured under similar conditions. Next, calculate the difference in contact angles: "contact angle of ion-exchanged water" - "contact angle of aqueous dispersion". They sought it.

[0067] (5) Film forming properties The film-forming properties were determined as follows. Using wire bars (OSG, OSP-15), plasma-treated polyester A water-based dispersion is placed on a film (manufactured by Toray Films, Lumirror (black), 100 μm thick). The coating was applied at a rate of 15 mm / second, and the width of the coating film after standing at 25°C for 30 minutes was measured from the liquid width at the time of application and the width of the coating film after standing at 25°C for 30 minutes. It was calculated based on the following formula. Film-forming performance evaluation index = (Width of coated film after standing / Width of liquid during application) Evaluation Criteria ◎: Film-forming performance evaluation index is 0.9 or higher ○: Film-forming performance evaluation index is 0.7 or higher and less than 0.9 ×: Film-forming performance index is less than 0.7

[0068] (6) Color development The color development was determined as follows: The reflected light of the structural color when white light is irradiated onto the surface of the structure after film formation is evaluated using the following criteria The decision was made based on the criteria. ◎: When monochromatic metallic luster is confirmed and angle-dependent color dependence is confirmed. △: When metallic luster is not observed, but monochromatic reflection is observed. ×: When a single-color reflection cannot be observed.

[0069] [Raw materials, etc.] Styrene (manufactured by Denka Co., Ltd.) Acrylic acid (manufactured by Mitsubishi Chemical Corporation) Sodium styrene sulfonate (manufactured by Tosoh Finechem Co., Ltd.) Sodium bicarbonate (manufactured by Fujifilm Wako Co., Ltd.) Ammonium persulfate (manufactured by Kanto Chemical Co., Ltd.)

[0070] Water-soluble resin Ionic PVA: Anionic polyvinyl alcohol-based resin (manufactured by Mitsubishi Chemical Corporation, etc.) (Senex CKS50) Water-soluble polyester: Anionic polyester resin (manufactured by Mitsubishi Chemical Corporation, Nichigo) Polyester WR905) Nonionic PVA: Nonionic polyvinyl alcohol-based resin (manufactured by Mitsubishi Chemical Corporation) Nichigo G Polymer)

[0071] [Example 1] A monomer mixture was prepared by mixing 98.4 parts of styrene with 1.5 parts of acrylic acid. On the other hand, 0.1 parts sodium styrenesulfonate and 0.15 parts sodium bicarbonate are added to the ion A solution of the auxiliary agent [A] was prepared by dissolving it in 16.4 parts of water-exchanged water. A reaction chamber equipped with a stirring device, a heating and cooling device, a nitrogen introduction device, and a raw material / auxiliary agent loading device. Place 177.5 parts of deionized water into the container, then rotate at 150 rpm while adding the auxiliary agent. Solution [A] was added, and the internal temperature was raised to 80°C. Next, dissolve 0.42 parts of ammonium persulfate in 33.7 parts of deionized water in the reaction vessel. The initiator solution was added, and 5 minutes later, the monomer mixture was added dropwise over 3 hours. After the monomer mixture was added dropwise, polymerization treatment was carried out for 5 hours. Deionized water was added as needed to maintain a constant liquid level during the subsequent polymerization reaction. Subsequently, the polymerization reaction product is filtered through nonwoven gauze (Treat) to obtain an emulsion of organic fine particles. I obtained the n.

[0072] The obtained organic microparticles had a number-average particle size of 246 nm, a CV value of 6.4%, and a solid content concentration of 29%. The percentage was 0%, and the yield was 98.5%. Organic fine particles are uniform particles because only one type of monomer mixture is used, and Tg is The temperature was calculated to be 100°C using Fox's formula.

[0073] To this emulsion, add ionic PVA as a water-soluble resin, per 100 parts of organic fine particles. Add 0.01 part, neutralize with ammonia water, and then ionize to achieve a solid content concentration of 28%. The mixture was diluted with replacement water to prepare an aqueous dispersion. After thoroughly dispersing the aqueous dispersion, a plasma-treated polyester film (Toray) is formed. A wire bar (OSG, OSP) is placed on top of a film-based Lumirror (black, 100 μm thick). Using -15), the structure was obtained by coating at 15 mm / second and drying at 25°C for 3 minutes. .

[0074] [Example 2] As a water-soluble resin, 0.05 parts of ionic PVA were added per 100 parts of organic fine particles. Except for that, the structure was obtained in the same manner as in Example 1.

[0075] [Example 3] As a water-soluble resin, ionic PVA was added in a quantity of 0.1 parts per 100 parts of organic fine particles. Except for the above, the structure was obtained in the same manner as in Example 1.

[0076] [Example 4] As a water-soluble resin, 0.4 parts of ionic PVA were added per 100 parts of organic fine particles. Except for the above, the structure was obtained in the same manner as in Example 1.

[0077] [Example 5] As a water-soluble resin, 0.05 parts of water-soluble polyester are added per 100 parts of organic fine particles. The structure was obtained in the same manner as in Example 1, except for the above.

[0078] [Example 6] As a water-soluble resin, 0.05 parts of nonionic PVA were added per 100 parts of organic fine particles. Except for that, the structure was obtained in the same manner as in Example 1.

[0079] [Example 7] As a water-soluble resin, 0.1 parts of nonionic PVA were added per 100 parts of organic fine particles. Except for the above, the structure was obtained in the same manner as in Example 1.

[0080] [Comparative Example 1] The structure was obtained in the same manner as in Example 1, except that a water-soluble resin was not added.

[0081] [Comparative Example 2] As a water-soluble resin, 0.5 parts of ionic PVA were added per 100 parts of organic fine particles. The structure was obtained in the same manner as in Example 1, except for the rest.

[0082] [Table 1]

[0083] As shown in Table 1, Examples 1 to 7 using the aqueous dispersion of the present invention exhibit excellent film-forming properties and color development. It was discovered that... Examples using 0.05 parts and 0.1 parts of a nonionic water-soluble resin (nonionic PVA) Compared to 6 and 7, 0.05 parts and 0.1 parts of ionic water-soluble resin (ionic PVA) are used. Examples 2 and 3 showed good color development. From this, it was found that nonionic water-soluble resins are better than It was found that using an ionic water-soluble resin is preferable.

[0084] In contrast, Comparative Example 1, which did not use a water-soluble resin, did not have sufficient film-forming properties and color development. Even that wasn't enough. Comparative Example 2, which used 0.5 parts of water-soluble resin, showed sufficient film-forming properties, but its color development was not sufficient. It wasn't there.

Claims

1. An aqueous dispersion containing fine particles and a water-soluble resin, The number-average particle diameter of the fine particles is 50 to 450 nm, and the CV value of the particle diameter based on the number is 10 It is less than %. A water-soluble resin is contained in a solution containing 0.001 to 0.4 parts by mass per 100 parts by mass of the fine particles. Gender dispersion.

2. The contact angle with the polyester film is different from the contact angle with water on the polyester film. The aqueous dispersion according to claim 1, having a temperature 2° or lower.

3. The aqueous dispersion according to claim 1 or 2, wherein the solid content concentration is 10% by mass or more.

4. The water-soluble resin is an ionic water-soluble resin, according to any one of claims 1 to 3. Aqueous dispersion.

5. The water-soluble resin is an ionic polyvinyl alcohol-based resin, according to any of claims 1 to 4. An aqueous dispersion as described in any one of the items.

6. A structure in which fine particles according to any one of claims 1 to 5 are arranged to produce color.

7. Furthermore, the structure according to claim 6, having an overcoat layer on its surface.

8. An aqueous dispersion containing fine particles that exhibit structural coloration when arranged and a water-soluble resin, A water-soluble resin is contained in a solution containing 0.001 to 0.4 parts by mass per 100 parts by mass of the fine particles. Gender dispersion.

9. The contact angle with the polyester film is different from the contact angle with water on the polyester film. The aqueous dispersion according to claim 8, having a temperature 2° or lower.

10. The aqueous dispersion according to claim 8 or 9, wherein the solid content concentration is 10% by mass or more.

11. The water-soluble resin is an ionic water-soluble resin, as described in any one of claims 8 to 10. an aqueous dispersion of the same.

12. The water-soluble resin is an ionic polyvinyl alcohol-based resin, according to claims 8 to 11. The aqueous dispersion described in any one of the items.

13. A structure in which fine particles according to any one of claims 8 to 12 are arranged to produce color.

14. Furthermore, the structure according to claim 13, having an overcoat layer on its surface.

15. A paint composition using the aqueous dispersion according to any one of claims 1 to 5 or 8 to 12.

16. An ink composition using the aqueous dispersion according to any one of claims 1 to 5 or 8 to 12.

17. A cosmetic composition using the aqueous dispersion described in any one of claims 1 to 5 or 8 to 12.

18. Decorative film using the aqueous dispersion according to any one of claims 1 to 5 or 8 to 12 。

19. An optical material using an aqueous dispersion according to any one of claims 1 to 5 or 8 to 12.

20. A paint composition using the structure described in claim 6, 7, 13, or 14.

21. An ink composition using the structure described in claim 6, 7, 13, or 14.

22. A cosmetic composition using the structure described in claim 6, 7, 13, or 14.

23. A decorative film using the structure described in claim 6, 7, 13, or 14.

24. An optical material using the structure described in claim 6, 7, 13, or 14.

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