Aqueous dispersion composition for structural color development

Abstract

To provide a structure having an excellent planar shape which exhibits structural coloration, maintains mirror surface properties, suppresses the occurrence of liquid pooling, makes it difficult for defects to occur in an obtained crystal structure, and provides sufficient leveling properties even when a simple coating method such as spray coating is used.SOLUTION: Used is an aqueous dispersion composition for structural color development, which has colloidal particles, a solvent (A) having a boiling point of less than 100°C, and a solvent (B) having a boiling point of 100°C or more but less than 200°C and a solubility in water of 260 g / L or more (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous dispersion composition for structural color development, and a method for producing a structural color-developing laminate using the same. [Background technology]

[0002] Structural coloring refers to the coloring phenomenon caused by microscopic structures at or below the wavelength of light. Familiar examples of structural color include compact discs, soap bubbles, morpho butterflies, and jewel beetles. These objects themselves are not colored, but appear colored because light is reflected and interfered by their microscopic structures. In recent years, development has been progressing to artificially create regular structures that exhibit structural color.

[0003] This structure is obtained by dispersing colloidal particles in a solvent to prepare a dispersion, which is then coated onto a substrate to form a colloidal particle layer. When the colloidal particles are arranged in an orderly manner, they form a photonic crystal structure and emit structural colors. In Patent Document 1, when a single solvent is used, there may be areas in the crystal structure where colloidal particles are not arranged, resulting in defects. To prevent this, a solvent mixture containing at least two specific organic solvents is used. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2022-245099 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the coating liquid obtained by the method of Patent Document 1 is applied by a simple method such as spray coating, the coating liquid may not be applied cleanly, resulting in pools of liquid collecting in some areas, or the leveling ability of the coated layer to become uniform before solidification may be insufficient. Furthermore, although the amount of generation is reduced, defects such as the lack of alignment of colloidal particles may occur. Furthermore, the specularity of the resulting crystal structure may be insufficient. Therefore, an object of the present invention is to solve the above-mentioned problems. That is, an object of the present invention is to provide a structure having an excellent surface state, which exhibits structural coloring, maintains specularity, suppresses the occurrence of liquid pools, reduces the occurrence of defects in the resulting crystal structure, and provides sufficient leveling properties, even when a simple coating method such as spray coating is used. Another object of the present invention is to provide a dispersion of fine particles to be used in forming the fine particle structure. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by using a specific solvent mixture, and have arrived at the present invention.

[0007] That is, the present invention has the following features. [1] A structural coloring aqueous dispersion composition comprising colloidal particles, a solvent (A) having a boiling point of less than 100°C, and a solvent (B) having a boiling point of 100°C or more but less than 200°C and a solubility in water of 260 g / L or more. [2] The aqueous dispersion composition according to [1], wherein the aqueous dispersion composition contains 5 parts by mass or more of water per 100 parts by mass of the total mass. [3] The aqueous dispersion composition according to [1], wherein the solvent (A) and the solvent (B) are alcohol-based solvents. [4] The aqueous dispersion composition according to [1], wherein the total mass of the solvent (A) and the solvent (B) is 5 parts by mass or more and 2000 parts by mass or less per 100 parts by mass of water. [5] The aqueous dispersion composition according to [1], which contains 5 parts by mass or less of a leveling agent per 100 parts by mass of the total of water, solvent (A) and solvent (B). [6] A coating material comprising the aqueous dispersion composition according to any one of [1] to [5]. [7] A writing implement containing the paint described in [6]. [8] A method for producing a laminate, which comprises applying the aqueous dispersion composition according to any one of [1] to [5] to a substrate. [9] A method for producing a laminate, comprising applying the aqueous dispersion composition according to any one of [1] to [5] to a substrate using a spray gun. [Effects of the Invention]

[0008] The structural coloring aqueous dispersion composition of the present invention uses at least two specific solvents, and therefore, even if a simple coating method such as spray coating is used instead of a precision coating method, structural coloring and specularity can be maintained, while suppressing the occurrence of liquid pools, making it difficult for defects to occur in the resulting crystal structure, and achieving sufficient leveling properties, thereby making it possible to obtain a structure that is excellent in terms of surface appearance. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes in detail the embodiments of the present invention. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to the following content as long as it does not exceed the gist of the present invention. Furthermore, when the expression "to" is used in this specification, it is intended to include the numerical values ​​or physical values ​​written before and after it. Furthermore, numerical values ​​or physical values ​​written as upper and lower limits are intended to include those values.

[0010] The present invention relates to an aqueous dispersion composition for structural color development, which contains colloidal particles and at least two predetermined solvents. <Fine particles> The colloidal particles are composed of fine particles having a volume average particle size of 0.1 to 10 μm and a CV value of the particle size based on number of 15% or less. The fine particles are not particularly limited as long as the number average particle size and the CV value of the particle size based on the number are within the above ranges, and may be organic or inorganic fine particles.

[0011] [Volume average particle size] The volume average particle diameter of the fine particles is 0.1 to 10 μm, preferably 0.1 to 5 μm, and more preferably 0.1 to 1 μm. If the volume average particle diameter is within the above range, it is preferable because the structural coloring property is good. The method for measuring the number average particle diameter of the present invention is as described in the Examples.

[0012] [CV value of particle size based on number] The CV value of the particle size based on the number of particles of the present invention is preferably 15% or less, preferably 10% or less, and more preferably 5% or less. There is no particular restriction on the lower limit of the CV value of the particle size based on the number, but it is usually 1% or more. If the CV value of the particle size based on the number is within the above range, it is preferable because the design properties are good. The CV value is also called the "coefficient of variation" or "relative standard deviation," and in the present invention means the relationship between the standard deviation in the particle size distribution based on the number and the number average particle size, (standard deviation / number average particle size) x 100 It is calculated as follows. The microparticles have the CV value of the particle diameter based on the number as described above, and therefore, when a colloidal crystal layer is formed using the raw material microparticles by the method described below, the colloidal crystals are arranged in a regular pattern, which can produce structural coloring and contribute to improved design properties. The method for measuring the CV value of the particle size based on the number of particles in the present invention is as described in the Examples.

[0013] [Organic fine particles] The organic fine particles are preferably organic polymer fine particles. The organic polymer fine particles refer to fine particles made of a general organic polymer. Common organic polymers include, for example, polyamides, polyimides, low-density polyethylene, high-density polyethylene, poly(meth)acrylic acid esters, polystyrenes such as polystyrene and its derivatives, polyvinyl chloride, phenolic resins, and polycarbonate.

[0014] [Poly(meth)acrylic acid esters] The poly(meth)acrylic esters are polymers whose main component is a (meth)acrylic ester unit, where the main component means that the content of the (meth)acrylic ester unit relative to the entire polymer is 50% by mass or more, and even 60% by mass or more.

[0015] Examples of the (meth)acrylic acid ester that serves as the raw material for the (meth)acrylic acid ester unit include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate.

[0016] The poly(meth)acrylic acid esters may be either random copolymers or block copolymers, but are generally random copolymers. The poly(meth)acrylic acid esters may be copolymerized with any monomer in addition to the above-mentioned (meth)acrylic acid esters.

[0017] Examples of this optional monomer include styrenes such as styrene and methylstyrene; metal salts such as sodium salt of styrenesulfonic acid; acidic monomers such as acrylic acid and methacrylic acid; and acrylamides such as acrylamide and N-propylacrylamide. Among these, metal salts such as sodium salt of styrenesulfonic acid are preferred because they allow good control of the particle size. When a crosslinked structure is to be introduced into the poly(meth)acrylic acid ester, a known polyfunctional monomer may be copolymerized.

[0018] [Polystyrenes] The polystyrenes are polymers containing styrene units as the main component, where the main component means that the content of styrene units in the entire polymer is 50% by mass or more, and further 60% by mass or more. The polystyrenes may be random copolymers or block copolymers, but are generally random copolymers. The polystyrenes may be copolymerized with any monomer in addition to styrene.

[0019] Examples of the optional monomer include styrenes other than styrene, such as methylstyrene and chlorostyrene; metal salts such as sodium salt of styrenesulfonic acid; acidic monomers such as acrylic acid and methacrylic acid; (meth)acrylic acid esters such as methyl (meth)acrylate and ethyl (meth)acrylate; and acrylamides such as acrylamide and N-propylacrylamide. Among these, metal salts such as sodium salt of styrenesulfonic acid are preferred because they allow good control of the particle size. When a crosslinked structure is to be introduced into polystyrenes, a known polyfunctional monomer may be copolymerized.

[0020] The polystyrenes preferably contain 80.0 to 99.75% by mass of styrene units. If the content of styrene units is within the above range, the refractive index of the particles increases, and structural coloring properties are improved, which is preferable. The content of the styrene unit is more preferably 90.0% by mass or more, and more preferably 99.4% by mass or less.

[0021] The polystyrenes preferably contain 0.25 to 20.0 mass % of acidic monomer units such as acrylic acid units, methacrylic acid units, etc. If the content of the acidic monomer units is within the above range, cullets during polymerization are reduced, which is preferable. The content of the acidic monomer unit is more preferably 0.6% by mass or more, and more preferably 10.0% by mass or less.

[0022] When the polystyrenes contain any monomer unit other than the acidic monomer unit and / or polyfunctional monomer unit, the content thereof is preferably 3% by mass or less, more preferably 2% by mass or less. If the content is 3% by mass or less, the particle size can be well controlled.

[0023] [Preferred organic fine particles] Among these, poly(meth)acrylic acid esters and polystyrenes are preferred because raw materials are easily available and it is easy to produce fine particles with a uniform particle size, and polystyrenes are more preferred because they can produce polymers with a high refractive index. A polymer with a high refractive index is preferred because it increases the difference in refractive index between the inside and outside of the particle and improves structural color development. The organic fine particles may be made of a non-crosslinked polymer or a crosslinked polymer.

[0024] In order to achieve the effects of the present invention, the organic fine particles must have a uniform particle size. To obtain organic fine particles with a uniform particle size, for example, a polymer of an appropriate size is obtained by bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, etc., which is then pulverized into fine powder, and the particle size is made uniform by sieving, etc. Another method is to directly obtain organic fine particles with a uniform particle size by soap-free emulsion polymerization. Among these, the method using soap-free emulsion polymerization is preferred because of its excellent productivity.

[0025] [Method of manufacturing organic fine particles] Examples of methods for producing the organic fine particles include a method in which a polymer of an appropriate size is obtained by bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, etc., and then pulverized into fine powder, which is then subjected to a procedure such as sieving to make the particle size uniform. Another method is to directly obtain organic fine particles of a uniform particle size by soap-free emulsion polymerization. Among these, the method using soap-free emulsion polymerization is preferred because of its excellent productivity. This soap-free emulsion polymerization is a known polymerization method, for example, as follows. Deionized water is charged into a reaction vessel, and while heating and stirring as necessary, a polymerization aid is added to thoroughly disperse the polymerization aid in the deionized water. Next, a polymerization initiator is added while continuing to stir. Then, while continuing to stir, the monomers are gradually added dropwise to initiate the polymerization reaction. As the polymerization proceeds, particles are formed.

[0026] The solid concentration during polymerization, that is, the concentration of fine particles relative to the entire system during polymerization, is preferably 20 to 40% by mass. If the solid content concentration during polymerization is equal to or higher than the lower limit, productivity of organic fine particles is improved, and if it is equal to or lower than the upper limit, no cullet is generated during polymerization and no deposits are formed on the inner walls of the polymerization apparatus. When a polymerization initiator is used, the polymerization temperature is generally set to 60 to 90° C. After the reaction is completed, organic fine particles are taken out as an emulsion.

[0027] The pH of the emulsion is preferably 3.0 to 11.0 If the pH of the emulsion is outside the above range, productivity will be poor from the viewpoint of metal corrosion. Therefore, if the pH of the emulsion is outside the above-mentioned preferred range, it is preferable to adjust the pH by adding an alkali or acid as appropriate. Since the pH of the emulsion obtained by the production of the organic fine particles is usually about 2.0 to 7.0, the pH is generally adjusted by adding an alkali. The alkali used for pH adjustment is preferably ammonia water, because it can be easily removed from the structure by heating or the like.

[0028] Examples of polymerization initiators used in soap-free emulsion polymerization include water-soluble polymerization initiators such as sodium persulfate, potassium persulfate, and ammonium persulfate; oil-soluble polymerization initiators such as benzoyl peroxide and lauryl peroxide; and redox-based polymerization initiators formed by combining an oxidizing agent and a reducing agent. These may be used alone or in combination of two or more. Among these, water-soluble polymerization initiators are preferred because they are easy to handle.

[0029] [Inorganic fine particles] Examples of the inorganic fine particles include metal particles and metal oxides. Among these, silica fine particles are preferred because they are easily available and have excellent coating properties.

[0030] (Production of inorganic fine particles) The inorganic fine particles of the present invention can be obtained by granulating metal or metal oxide to a predetermined size and then sieving the granulated particles to make the particle diameter uniform.

[0031] [Structural coloring aqueous dispersion composition] The structural color-developing aqueous dispersion composition of the present invention (hereinafter, sometimes simply referred to as "aqueous dispersion composition") is an aqueous dispersion composition that contains the fine particles (colloidal particles) and at least two predetermined types of solvents, as described above.

[0032] [solvent] The solvent is a dispersion medium for dispersing the fine particles, and contains at least two types of solvent: a solvent having a boiling point of less than 100°C (hereinafter referred to as "solvent (A)"), and a solvent having a boiling point of 100°C or more but less than 200°C and a solubility in water of 260 g / L or more (hereinafter referred to as "solvent (B)"). Furthermore, the aqueous dispersion composition contains water in addition to solvent (A) and solvent (B).

[0033] [Solvent (A)] As described above, the solvent (A) is a solvent having a boiling point of less than 100°C, and examples thereof include alcoholic solvents such as methyl alcohol, ethyl alcohol, 1-propanol, and 2-propanol, as well as acetone, tetrahydrofuran, methyl ethyl ketone, and ethyl acetate.

[0034] [Solvent (B)] As described above, the solvent (B) refers to a solvent having a boiling point of 100°C or higher but lower than 200°C and a solubility in water of 260 g / L or higher, and examples of the solvent include alcohol solvents such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, and 1-methoxy-2-propanol. Examples include:

[0035] [Contents of water and each solvent in aqueous dispersion composition] In the aqueous dispersion composition, the water content is preferably 5 parts by mass or more, and preferably 20 parts by mass or more, relative to a total mass of 100 parts by mass. By including 5 parts by mass or more, the characteristic of promoting colloid formation can be exhibited. Furthermore, the water content is preferably 90 parts by mass or less, and preferably 80 parts by mass or less. By including 90 parts by mass or less, the characteristic of improving leveling properties can be exhibited.

[0036] In the aqueous dispersion composition, the total amount of solvent (A) and solvent (B) is preferably 5 parts by mass or more, and more preferably 50 parts by mass or more, per 100 parts by mass of the aqueous dispersion composition. By including 5 parts by mass or more, the leveling property is improved and the drying speed can be shortened. Furthermore, the total amount is preferably 2000 parts by mass or less, and more preferably 500 parts by mass or less. By including 2000 parts by mass or less, the formation of colloidal crystals can be promoted.

[0037] Furthermore, in the aqueous dispersion composition, the content ratio of solvent (A) to solvent (B) is preferably 1 / 100 or more, and more preferably 1 / 50 or more, solvent (A) / solvent (B). By making it 1 / 100 or more, the characteristic of improved leveling can be exhibited. Furthermore, the ratio is preferably 100 / 1 or less, and more preferably 50 / 1 or less. By containing 100 / 1 or less, the characteristic of promoted colloidal crystal formation can be exhibited.

[0038] [Leveling agent] The aqueous dispersion composition may contain a leveling agent, such as sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, acrylic silicone, polyether silicone, or polyamide, as long as the effect of the present invention is not impaired. The content of this leveling agent is preferably 5 parts by mass or less, and more preferably 2 parts by mass or less, relative to 100 parts by mass of the total of the water, solvent (A), and solvent (B). By including 5 parts by mass or less, the characteristic of promoting the formation of colloidal crystals can be exhibited. Furthermore, the content is preferably 0.01 parts by mass or more, and more preferably 0.05 parts by mass or more. By including 0.01 parts by mass or more, the characteristic of improving leveling properties can be exhibited.

[0039] [Solids concentration of aqueous dispersion composition] The solid content of the aqueous dispersion composition is preferably 10% by mass or more, more preferably 20% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less. When the solid content concentration of the aqueous dispersion composition is within the above range, the film-forming properties are good, and the structural color development of the resulting colloidal crystal film is good. Here, the solid content of the dispersion refers to the components other than the dispersion medium in the dispersion, and is usually the total of the fine particles and other components that may be contained as needed. The solids concentration of the dispersion can be measured in the same manner as the solids concentration of the emulsion described in the Examples section below, but it can also be calculated from the solids concentration and component amounts of each component used in producing the dispersion.

[0040] [Other ingredients] The aqueous dispersion composition of the present invention may contain, as necessary, other components such as a plasticizer, a film-forming aid, a pH adjuster, and the like, in addition to the fine particles, water, solvent (A), solvent (B), and a leveling agent used as needed, within the scope of the present invention.

[0041] [Method for preparing aqueous dispersion composition] The aqueous dispersion composition of the present invention can be prepared by mixing the fine particles, water, solvent (A), solvent (B), and other components used as needed. For example, it can be prepared by mixing the emulsion containing fine particles produced by the above-mentioned method with solvent (A), solvent (B), and other components used as needed.

[0042] [Laminates, paints, etc.] The aqueous dispersion composition according to the present invention can be applied to a substrate by coating or the like to form a layer of colloidal particles on the substrate, thereby obtaining a laminate. Furthermore, in this laminate, an overcoat layer can be provided on the surface of the colloidal particle layer as needed to protect the surface of the colloidal particle layer.

[0043] The aqueous dispersion composition according to the present invention can be used as a coating material either directly or by adding other components to the aqueous dispersion composition as needed. When used as a coating material, the aqueous dispersion composition can be included as a component of ink and used in writing instruments such as fountain pens, color markers, and gel ink ballpoint pens.

[0044] [Base material] The substrate is a material that serves as the base of the laminate, and is not particularly limited, and general materials such as metal, resin, wood, and paper can be used. For example, thermoplastic resin substrates such as polyvinyl chloride sheets, polyester films such as polyethylene terephthalate (PET), polypropylene films, polyethylene films, nylon films, polystyrene films, and polyvinyl alcohol films, metal substrates such as aluminum foil, glass substrates, and coated paper substrates can also be used. When the above-mentioned film-like material is used as the substrate, the resulting structure is in the form of a film.

[0045] The substrate may have a smooth or uneven surface, and may be transparent, translucent, or opaque. It is also possible to use a substrate that has been pre-colored, such as black. Two or more of the above substrates may be laminated together. The substrate may be subjected to a corona treatment or plasma treatment in advance to improve the coatability of the dispersion of the present invention. A primer layer may be provided on the substrate.

[0046] [Overcoat layer] The overcoat layer is a layer for protecting the surface of the colloid particle layer, and is not particularly limited as long as it is made of a material that forms a film on the surface of the structure. The overcoat layer may cover the surface of the colloid particle layer and may also be filled between the colloid particle layers. Examples of the resin that constitutes the overcoat layer include acrylic resin, acrylic urethane resin, silicone resin, and epoxy resin. The resin is generally in the form of a solventless resin, a resin solution diluted with an arbitrary solvent, or an emulsion dispersed in water.

[0047] The thickness of the overcoat layer is not particularly limited, as long as it is thick enough to cover the colloid particle layer or thicker. The overcoat layer can be formed on the surface of the structure by applying a thin film of the resin or a precursor thereof onto the colloid particle layer, and optionally subjecting it to heat treatment, etc. For example, the overcoat layer can be formed by applying a precursor of a material constituting the overcoat layer or a heated fluid, etc., onto the surface of the colloidal crystal layer, followed by curing, cooling, etc.

[0048] <Manufacturing of laminate> The laminate of the present invention can be produced, for example, by the following method. The aqueous dispersion composition is applied onto the substrate and then dried at an appropriate temperature, resulting in the microparticles being periodically arranged in three dimensions.

[0049] Examples of a method for applying the aqueous dispersion composition to a substrate include a printing method that does not use a plate, such as inkjet printing, spraying, dipping, or spin coating, and a printing method that uses a plate, such as an offset gravure coater, gravure coater, doctor coater, bar coater, blade coater, flexo coater, or roll coater. Additionally, a drawing method using a writing instrument such as a fountain pen, a color marker, or a gel ink ballpoint pen can be used. Furthermore, as a simpler coating method, a method of spraying onto a substrate with a spray gun can be employed. When the aqueous dispersion composition of the present application is used, even when a simple coating method such as a method using a spray gun is employed, liquid pooling is unlikely to occur, leveling properties are excellent, defects in the resulting crystal structure are unlikely to occur, and specularity can be maintained.

[0050] The coating thickness of the aqueous dispersion composition of the present invention varies depending on the solids concentration of the dispersion, but is preferably 1 to 100 μm, more preferably 5 to 50 μm, and even more preferably 10 to 30 μm. When the coating thickness is 1 μm or more, the structural coloring properties of the resulting colloid particle layer are improved. When the coating thickness is 100 μm or less, the ordered arrangement of the resulting colloid particle layer is improved, and the structural coloring properties are improved.

[0051] There are no particular limitations on the drying method used after the aqueous dispersion composition of the present invention has been applied to a substrate, and any conventionally known method can be used, such as heat drying, hot air drying, infrared drying, microwave drying, drum drying, etc. The above drying methods may be used alone or in combination. If the drying temperature is too high, the dispersion medium will volatilize rapidly, disrupting the alignment of the colloid particle layer and adversely affecting color development. On the other hand, if the drying temperature is too low, it may lead to uneven drying, making it impossible to obtain a uniform colloid particle layer. From the viewpoint of the alignment of the colloid particle layer, the drying temperature is preferably in the range of 10 to 120°C, particularly 20 to 100°C. The drying time varies depending on the drying temperature, but is preferably 0.5 to 30 minutes, more preferably 1 to 10 minutes, from the viewpoint of the alignment of the colloidal particle layer. The laminate according to the present invention can be obtained by the above method, and by drying by the above method, a colloid particle layer in which fine particles are periodically arranged three-dimensionally can be formed.

[0052] [Structural coloring] The microparticles of the present invention have structural coloring properties when they are formed into a layer of colloidal particles periodically arranged in three dimensions. Structural coloring means that structural color is exhibited when microparticles of uniform particle diameter are regularly arranged. Structural coloring is a phenomenon in which a material has a crystalline structure in which fine particles are regularly arranged, and optical physical phenomena such as interference and scattering occur depending on the wavelength of light, causing the material to appear colored.

[0053] Since structural coloring is due to the properties of light, it appears not only in the visible light region but also in the ultraviolet and infrared regions. To produce structural colors in the ultraviolet region, fine particles with a small number-average particle diameter should be used, and to produce structural colors in the infrared region, fine particles with a large number-average particle diameter should be used. Here, the visible light region refers to wavelengths of 360 to 830 nm, the ultraviolet region refers to wavelengths of 200 to 359 nm, and the infrared region refers to wavelengths of 831 to 2500 nm.

[0054] [Colloidal particle layer] The colloid particle layer of the present invention refers to a substance that exhibits structural color, specifically, a substance containing colloid aggregates that exhibit structural color, in which fine particles contained in the aqueous dispersion composition are periodically arranged in three dimensions. Here, the colloidal aggregate refers to a colloidal crystal or a colloidal amorphous aggregate. By arranging the fine particles, the fine particles form a colloidal crystal or a colloidal amorphous aggregate, that is, a colloidal aggregate. Furthermore, a material that exhibits structural color is one in which fine particles of uniform diameter are regularly arranged, causing diffraction and interference of light, resulting in an angle-dependent color that appears to change depending on the viewing angle.

[0055] Examples of the colloid particle layer include a layer in which fine particles are arranged on a substrate, and a layer in which colloid particles are peeled off from a layer in which fine particles are arranged on a substrate without damaging the regular arrangement of the fine particles.

[0056] In one embodiment, the colloid particle layer of the present invention is characterized by containing fine particles having a volume average particle diameter of 0.1 to 10 μm and a CV value of particle diameter based on number of 15% or less. In this case, the fine particles contained in the colloid particle layer preferably have the same properties as the fine particles in the dispersion of the present invention described above, and more preferable ranges can also be considered similarly.

[0057] [Reflectance of colloidal particle layer] The colloid particle layer of the present invention preferably has a reflectance derived from structural coloring of 5% or more in the wavelength range of 180 to 2500 nm. The reflectance of the colloid particle layer can be increased to 5% or more by using, for example, the dispersion of the present invention. The reflectance is more preferably 10% or more, and even more preferably 20% or more. If the reflectance is 5% or more, it is preferable because the structural coloring property is excellent. The reflectance due to structural coloring can be measured by the method described in the Examples below.

[0058] [Application] The aqueous dispersion composition of the present invention can be suitably used alone or as a secondary processing material, for example, in paint compositions such as stationery paints, toy paints, paints for vehicles such as railways, automobiles, and bicycles, paints for aircraft, paints for furniture, and paints for building walls; ink compositions such as inkjet recording inks, gravure printing inks, and stationery inks; writing instruments using these ink compositions, such as fountain pens, color markers, and gel ink ballpoint pens; cosmetics, such as foundations, lipsticks, lip balms, blushers, eyebrow cosmetics, and nail polish cosmetics; decorative films, such as color sheets, decorative films, and packaging films; optical materials, such as reflective displays, discoloration sensors, anti-counterfeiting agents, electrodeposited color plates, and color filters; window film materials; and optical films, such as polarizing films and light-diffusing films.

[0059] The colloidal crystal layer can also be suitably used, either alone or as a secondary processed material, in decorative films such as color sheets, decorative films, and packaging films; optical materials such as reflective displays, discoloration sensors, anti-counterfeiting agents, electrodeposited color plates, and color filters; window film materials; and optical films such as polarizing films and light diffusing films.

[0060] Furthermore, the laminate can be suitably used alone or as a secondary processed material for decorative films such as color sheets and decorative films; and optical materials such as reflective displays, discoloration sensors, anti-counterfeiting agents, electrodeposited color plates, color filters, and polarizing films. [Example]

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. In the following description, "parts" and "%" indicate "parts by mass" and "% by mass", respectively.

[0062] [Evaluation method] In the following examples and comparative examples, various physical properties were measured by the following methods. (1) Volume average particle size of fine particles In the present invention, the volume median diameter is used as the volume average particle diameter. Measurements were performed using NanotracWave II manufactured by Microtrac Bell Co., Ltd. and the company's analysis software, Microtrac Date Management System. Specifically, a sample dispersion was prepared by mixing 0.02 g of the aqueous dispersion composition with 20 mL of diluted sodium dodecylbenzenesulfonate (0.02% concentration), and this sample dispersion was placed in a sample cell and measured under the following conditions: solvent refractive index: 1.333, measurement time: 180 seconds, number of measurements: 1. Other conditions were: particle refractive index: 1.59, transparency: transparent, shape: spherical, density: 1.00.

[0063] (2) CV value of particle size based on the number of fine particles The aqueous dispersion composition was applied to a substrate, dried, and then an image of the microparticles was observed using an electron microscope at a magnification of 20,000 times or more. The diameters of at least 400 microparticles in the image were measured, and the arithmetic average was calculated to determine the number-average particle size. Then, (standard deviation / number-average particle size) × 100 was calculated to determine the CV value of the particle size based on the number.

[0064] (3) Solids concentration of aqueous dispersion composition The solids concentration of the aqueous dispersion composition was determined by heating 10 g of emulsion at 190°C for 60 minutes to evaporate the water using a heat-drying moisture meter MX-50 manufactured by A&D Corporation.

[0065] (4) Specularity The spray coating was performed using a spray gun (Wider 13H2GEC) at an air pressure of 0.4 MPa and a distance of 140 mm from the substrate. After coating, the mixture was dried at 25°C for 10 minutes to obtain a colloidal particle laminate. The obtained laminate was allowed to stand at 25° C. for 30 minutes, and then a 5 cm square sample was cut out from the formed laminate and subjected to spectroscopic measurement. The samples were photographed by the following method, and the resulting photographic images were evaluated for specularity according to the following criteria. ·photo shoot The substrate was photographed at a distance of 300 mm from the substrate, with a lit straight tube fluorescent lamp (Panasonic FL40SSECW37F3D) positioned 3 m above the substrate, so that the light was reflected in the image. ·evaluation 〇: From the image of the fluorescent lamp, the straight tube of the fluorescent lamp can be easily identified as a straight line. △: It is difficult to see the straight tube of the fluorescent light from the image of the fluorescent light.

[0066] (5) Grain defects (4) Draw lines at 1 cm intervals on the sample obtained in the specular test, and visually inspect the lines at 1 cm intervals. 2 The number of grain defects (areas where colloidal particles are randomly gathered and whitened) per area was counted, and the average was calculated and evaluated. ○: Grain defects are 10 or less, △: Grain defects: over 10 and up to 30 ×: More than 30 grain defects.

[0067] (6) Leveling ability The specularity was judged and evaluated from the photographs of the samples obtained in (4) Specularity. 〇: No mottled patterns were observed. ×: A mottled pattern was observed.

[0068] (7) Liquid accumulation The width of the liquid pool at the coated edge of the laminate obtained in (4) Specularity was measured and evaluated. ○: The width of the liquid pool was 5 mm or more and 10 mm or less. ×: The width of the liquid pool exceeded 10 mm.

[0069] [Raw materials, etc.] The raw materials used in the following examples and comparative examples are as follows. Styrene (manufactured by Denka) Acrylic acid (Mitsubishi Chemical Corporation) Sodium styrene sulfonate (manufactured by Tosoh Finechem Co., Ltd.) Sodium bicarbonate (Fujifilm Wako Co., Ltd.) Ammonium persulfate (Kanto Chemical Co., Ltd.) Ethanol (Kanto Chemical Co., Ltd.) 1-Methoxy-2-propanol (Kanto Chemical Co., Ltd.) Leveling agent (Shin-Etsu Chemical Co., Ltd. Polyether silicone KP-120)

[0070] [Synthesis Example 1] Synthesis of fine particles A monomer mixture liquid was prepared by mixing 98.4 parts by mass of styrene and 1.5 parts by mass of acrylic acid. Separately, an auxiliary solution was prepared by dissolving 0.1 parts by mass of sodium styrenesulfonate and 0.15 parts by mass of sodium hydrogencarbonate in 16.4 parts by mass of ion-exchanged water. A reaction vessel equipped with a stirrer, a heating / cooling device, a nitrogen introducing device, and a raw material / auxiliary agent feeding device was charged with 177.5 parts by mass of ion-exchanged water, and then the auxiliary agent solution was fed while rotating at 150 rpm, and the internal temperature was raised to 77°C. Next, an initiator solution prepared by dissolving 0.42 parts by mass of ammonium persulfate in 33.7 parts by mass of ion-exchanged water was added to the reaction vessel, and after 5 minutes, the monomer mixture was successively added dropwise over 3 hours. After the monomer mixture was added, the temperature was raised to 90°C and the water was evaporated until the solid content reached 40%, after which the polymerization reaction product was filtered through nonwoven gauze (Treaty) to obtain an emulsion of fine particles. The resulting fine particles had a number-average particle size of 252 nm, a CV value of 6%, and a solid content of 40.0%.

[0071] [Example 1] The emulsion of fine particles was neutralized by adding ammonia water, and then 31.1 parts by mass of ion-exchanged water, 45.6 parts by mass of ethanol, and 0.25 parts by mass of a leveling agent were added to prepare an aqueous dispersion composition. After thoroughly dispersing the microparticle dispersion, a 30 μm thick film was formed on a plasma-treated polyester film (Toray Films, Lumirror (black): 100 μm thick) using a spray gun under the above conditions, and the film was dried at 25°C for 30 minutes to obtain a laminate.

[0072] [Example 2] A laminate was obtained in the same manner as in Example 1, except that the amount of ion-exchanged water was changed to 0.74 parts by mass, the amount of ethanol added was changed to 60.7 parts by mass, and the amount of 1-methoxy-2-propanol added was changed to 60.74 parts by mass.

[0073] [Comparative Example 1] A laminate was obtained in the same manner as in Example 1, except that 1-methoxy-2-propanol was not added and the amount of ethanol added was changed to 91.1 parts by mass.

[0074] [Table 1]

[0075] (result) As shown in Table 1, Examples 1 and 2, which used the aqueous dispersion composition of the present invention, were found to be excellent in all evaluation items. In contrast to this, in the comparative example in which no alcohol with a boiling point exceeding 100°C was used, the specular surface properties of the structural coloring were good, but the suppression of grain defects and the leveling properties were insufficient.

Claims

1. A structural coloring aqueous dispersion composition comprising colloidal particles, a solvent (A) having a boiling point of less than 100°C, and a solvent (B) having a boiling point of 100°C or more but less than 200°C and a solubility in water of 260 g / L or more.

2. The aqueous dispersion composition according to claim 1 , comprising 5 parts by mass or more of water per 100 parts by mass of the total mass.

3. The aqueous dispersion composition according to claim 1 , wherein the solvent (A) and the solvent (B) are alcohol-based solvents.

4. The aqueous dispersion composition according to claim 1 , wherein the total parts by mass of the solvent (A) and the solvent (B) is 5 parts by mass or more and 2,000 parts by mass or less per 100 parts by mass of water.

5. The aqueous dispersion composition according to claim 1 , comprising 5 parts by mass or less of a leveling agent per 100 parts by mass of the total of water, the solvent (A), and the solvent (B).

6. A paint comprising the aqueous dispersion composition according to any one of claims 1 to 5.

7. A writing implement comprising the coating material of claim 6.

8. A method for producing a laminate, comprising applying the aqueous dispersion composition according to any one of claims 1 to 5 to a substrate.

9. A method for producing a laminate, comprising applying the aqueous dispersion composition according to any one of claims 1 to 5 to a substrate using a spray gun.

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