hydrophilic components

Abstract

To provide a composition capable of forming a coating film which can suppress generation of sagging and can exhibit good hydrophilicity and durability when applied on the whole surface (in particular, a vertical surface) of a water section member having a three-dimensional shape.SOLUTION: There is provided a hydrophilic composition which comprises a hydrophilic component containing a compound A having a sulfonic acid group or a sulfonic acid salt group in one molecule and at least one ethylenically unsaturated group in one molecule, a film-forming component containing a compound B having 3 or more ethylenically unsaturated groups in one molecule and a hydroxyl group, organic particles and an organic solvent, wherein 20 wt.% of the film-forming component is contained in the hydrophilic composition, the total hydroxyl group value is 15 mgKOH / g or more and less than 175 mgKOH / g, the weight average molecular weight is 1000 g / mol or more, the functional group equivalent of the ethylenically unsaturated group is less than 242 g / eq and 1 wt.% or more and less than 50 wt.% of the organic particles is contained in the hydrophilic composition with respect to the film-forming component.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hydrophilic composition, and more particularly to a hydrophilic composition capable of forming a good film on the surface of a member having a three-dimensional shape. [Background technology]

[0002] One known means of imparting desired functions to various components surrounding our living environment is to provide coating films with the desired functions on the surfaces of these components, and at the same time, development of coating compositions for forming such coating films is also underway.

[0003] For example, Japanese Patent Laid-Open Publication No. 2014-233946 (Patent Document 1) describes a coating material containing sulfopropyl methacrylate potassium salt as a hydrophilic component, dipentaerythritol hexaacrylate, a polyfunctional acrylic monomer, and hydroxyethyl methacrylate, a volatile compound, Irgacure 500 as a photopolymerization initiator, water, and methoxyethanol as an organic solvent, as well as acrylic resin beads having a volume average particle size of 35 μm. The coating material is applied to the surface of a substrate (acrylic plate), dried by heating, and then cured by ultraviolet irradiation. The coating material is described as having good hydrophilicity and anti-slip properties due to the presence of sulfonic acid groups and acrylic resin beads on the surface, as well as durability (Examples 1 to 5, Table 1).

[0004] On the other hand, Patent Document 1 lists bathroom flooring, washbasin bowl materials, and other wet area components as examples of substrates (paragraph 0049), but as mentioned above, the only surface on which hydrophilicity and other functions have been specifically confirmed is the surface of the acrylic plate, i.e., the top surface of the three-dimensional wet area component. Therefore, it has not been confirmed or considered whether the same functions can be obtained on the vertical surfaces. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-233946 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors have discovered a problem in that when a paint having the composition disclosed in Patent Document 1 is applied to the entire surface of a three-dimensional plumbing component, the paint drips, particularly on the elevational surface. Furthermore, if a coating film obtained by applying a paint having the composition disclosed in Patent Document 1 to the surface of a plumbing component is subjected to strong stress after curing, such as by rubbing with force or cleaning with an abrasive or alkaline detergent, the surface of the coating film containing sulfonic acid groups may be scraped off, potentially resulting in the loss of the hydrophilicity once achieved. Therefore, it is desirable for the resulting coating film to be highly durable.

[0007] The present inventors attempted to increase the viscosity of the paint to prevent sagging, particularly on the vertical surfaces of wet-area components, when the paint disclosed in Patent Document 1 is applied to the entire surface of the wet-area component. Specifically, to thicken the paint, they considered (i) replacing the compound used as the film-forming component with one having a higher molecular weight. This approach was successful in preventing sagging after application and before curing. However, the polarity of the compound used as the film-forming component affected the state of sulfonic acid groups on the surface of the paint film, preventing hydrophilicity in the paint film. Furthermore, the structure of the compound used as the film-forming component sometimes prevented the paint film from achieving sufficient strength.

[0008] In addition, (ii) increasing the amount of particulate components in the paint was considered as a way to thicken the paint. This approach also prevented the paint from sagging after application and before curing. However, the presence of a large number of particulate components in the paint film affected the state of sulfonic acid groups on the surface of the paint film, reducing hydrophilicity, inducing cohesive failure, making the paint film brittle, or causing differences in thermal expansion, reducing the heat durability of the paint film.

[0009] On the other hand, in order to prevent dripping of the paint applied to the surfaces of the wet area components, we considered painting the paint separately on the top and bottom surfaces of the wet area components. This method resulted in the creation of a boundary surface (seam) between the paint film on the top surface and the paint film on the top surface, but if the seam was painted over, it could peel off, and on the other hand, if the seam was left as it was (unpainted), dirt would adhere to it, which posed a quality issue.

[0010] Thus, in paints capable of forming coating films that are hydrophilic and durable (strength, heat resistance, etc.), it has traditionally been difficult to simultaneously prevent the paint from dripping, particularly when applied to the vertical surfaces of bathroom components.

[0011] The present inventors have now discovered a coating composition that, when applied to the entire surface, particularly the vertical surfaces, of a three-dimensional water-related component, can suppress the occurrence of sagging and form a coating film that exhibits hydrophilicity and durability. In particular, by identifying the chemical properties of the film-forming components contained in the coating composition, they have confirmed that, when such a coating composition is applied to the entire surface, particularly the vertical surfaces, of a three-dimensional water-related component, it is possible to suppress the occurrence of sagging and form a coating film that exhibits good hydrophilicity and durability. The present invention is based on this finding.

[0012] Therefore, an object of the present invention is to provide a composition that, when applied to the entire surface (particularly the vertical surface) of a three-dimensional bathroom component, can suppress the occurrence of sagging and form a coating film that can exhibit good hydrophilicity and durability. [Means for solving the problem]

[0013] The hydrophilic composition according to the present invention is a hydrophilic component including a compound A having a sulfonic acid group or a sulfonate salt group and at least one ethylenically unsaturated group in one molecule; a film-forming component containing a compound B having three or more ethylenically unsaturated groups and a hydroxyl group in one molecule; Organic particles, Organic solvents and A hydrophilic composition comprising: The film-forming component is The hydrophilic composition contains 20% by weight or more of the hydrophilic composition, The total hydroxyl value is greater than 15 mgKOH / g and less than 175 mgKOH / g, Its weight average molecular weight is 1000 [g / mol] or more, and The functional group equivalent weight of the ethylenically unsaturated group is less than 242 [g / eq], The organic particles are contained in the hydrophilic composition in an amount of 1% by weight or more and less than 50% by weight of the film-forming component. It is characterized by the following. [Effects of the Invention]

[0014] According to the present invention, there is provided a hydrophilic composition that can suppress the occurrence of sagging when applied to the entire surface (especially the vertical surface) of a three-dimensional water-related component, and can form a coating film that can exhibit good hydrophilicity and durability. More specifically, the composition according to the present invention is thought to exhibit the following effects due to the intimate interaction of a specific hydrophilic component, a specific amount of a film-forming component having specific chemical properties, a specific amount of organic particles, and an organic solvent contained therein. After the composition is applied to a member, the occurrence of sagging can be suppressed until the composition is cured, and a cured film can be obtained that can maintain its hydrophilicity and durability. - After applying the composition to the surface of the part, no sagging occurs before the (wet) applied material dries. - (Wet) The surface does not sag (flow) during drying, and at the same time, as the organic solvent evaporates, segregation of the sulfonic acid groups contained in the hydrophilic component to the surface of the coating is thought to proceed, and - After the solvent evaporates and before the film hardens, the surface of the unhardened film does not flow or sag. The cured film obtained by curing the uncured film maintains high durability (strength) and does not chip off the surface even when subjected to strong stresses such as rubbing with force or cleaning with abrasives or alkaline detergents. This durability is thought to be due to the fact that the segregation of sulfonic acid groups to the surface of the component is maintained once the segregation is achieved, thereby maintaining hydrophilicity. In the above explanation, the meanings of the terms "cured film", "(wet) coating", "uncured film", and "segregation of sulfonic acid groups" will be explained later. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing an example of installation in a bathroom of a bathroom counter to which a hydrophilic composition according to the present invention can be applied. [Figure 2] 1 is a perspective view showing a bathroom counter to which a hydrophilic composition according to the present invention can be applied. DETAILED DESCRIPTION OF THE INVENTION

[0016] hydrophilic composition The hydrophilic composition according to the present invention comprises a hydrophilic component including a compound A having a sulfonic acid group or a sulfonate salt group and at least one ethylenically unsaturated group in one molecule; a film-forming component containing a compound B having three or more ethylenically unsaturated groups and a hydroxyl group in one molecule; Organic particles, Organic solvents and Includes:

[0017] Before describing each component contained in the hydrophilic composition according to the present invention, first, members to which the hydrophilic composition according to the present invention can be applied will be described below.

[0018] Purpose The hydrophilic composition according to the present invention can be applied to the surfaces of various members, preferably to the surfaces of members having a three-dimensional shape, and more preferably to the surfaces of resin members having a three-dimensional shape.

[0019] The hydrophilic composition according to the present invention can be preferably applied to the surface of a wet area component. In the present invention, the wet area component refers to a component used in a toilet, bathroom, kitchen, vanity, etc. Examples include, but are not limited to, bathroom wall materials, bathroom floor materials, bathroom counters, bathtubs, bathtub rims, bathroom window materials, bathroom door materials, shower booth wall materials, bathroom mirrors, vanity units, washbasins, kitchen counters, kitchen doors, storage shelves, storage boards, toilet bowls, toilet seats, warm water washing toilet seats and their cleaning nozzles, drains, faucets, range hood materials, etc. According to a preferred embodiment of the present invention, the wet area component to which the hydrophilic composition according to the present invention is applied is a three-dimensional wet area component.

[0020] As examples of three-dimensional bathroom components, a bathroom counter or a bathtub rim will be described using Figure 1. Figure 1 is a perspective view schematically showing an example of a bathroom. Bathroom 100 has multiple walls (side walls) including first to third walls 110-130, a floor, and a ceiling. The walls, floor, and ceiling form a bathroom space BS. Bathtub 90 is provided within bathroom space BS. Bathtub 90 has a rim, which users can grasp to enter and exit the bathtub. Bathroom 100 also has a faucet counter 11 and a sink counter 12 as counters 10. Faucet counter 11 dispenses water. Washbasin counter 12 is a relatively large, plate-shaped member on which items such as shampoo bottles and washbasins can be placed.

[0021] FIG. 2 is a perspective view showing one embodiment of a bathroom counter 200, such as the bathroom counter 10 shown in FIG. 1. Counter 200 has a top surface (water-receiving surface) 201, a vertical surface 202, and an end portion 203 connecting top surface 201 and vertical surface 202. Top surface 201 is a surface formed in the left-right direction, and vertical surface 202 is a surface formed in the up-down direction. Vertical surface 202 and end portion 203 are provided facing the drainage direction. End portion 203 is a surface through which water moving from above top surface 201 passes, and after passing through end portion 203, this water moves downward and is drained. End portion 203 is provided downward from top surface 201, and includes a curved portion having an arc-shaped cross section with a predetermined radius of curvature.

[0022] The hydrophilic composition of the present invention is preferably applied (e.g., coated) to the entire surface of a three-dimensional bathroom component. In particular, on surfaces that are inclined (relative to the horizontal plane), such as the vertical surface 202 and edge 203 of the counter shown in Figure 2, dripping of the composition is suppressed, allowing a cured film with a uniform thickness to be formed. This uniformity of the cured film allows it to exhibit good hydrophilicity and durability.

[0023] Each component contained in the hydrophilic composition according to the present invention will be described below. Hereinafter, the "hydrophilic composition according to the present invention" may also be referred to as the "composition according to the present invention" or simply as the "composition." Furthermore, a film obtained by curing the "composition" may also be referred to as a "cured film of the composition" or simply as a "cured film."

[0024] Hydrophilic component In the present invention, the hydrophilic component includes a compound A having a sulfonic acid group or a sulfonate salt group and at least one ethylenically unsaturated group in one molecule. Compound A Compound A contains a sulfonic acid group or a sulfonate salt group. The presence of a sulfonic acid group or a sulfonate salt group enables a cured film of the composition according to the present invention to exhibit hydrophilicity. Having hydrophilicity is advantageous in that, for example, when the composition according to the present invention is applied to the surface of a wet-related component, drainage and drying properties are improved, making it possible to inhibit adhesion of stains such as water stains due to residual water, and further inhibiting adhesion of oil. A cured film of the composition according to the present invention preferably contains more sulfonic acid groups or sulfonate salt groups on its surface than in its interior. That is, a cured film of the composition according to the present invention preferably has sulfonic acid groups segregated on its surface.

[0025] As described below, a cured film of the composition according to the present invention can be obtained as follows: First, the composition is applied to a substrate, and the (wet) coating of the composition applied to the substrate is dried to obtain a (dried) coating. The (dried) coating of the composition is then cured to obtain a cured film of the composition. Herein, the dried (wet) coating, i.e., the (dry) coating, is also referred to as an "uncured film" because it is subsequently cured. As described above, it is believed that segregation of sulfonic acid groups on the surface of a cured film of the composition according to the present invention can be achieved by, but is not limited to, the following process: By drying the (wet) coating of the composition, i.e., by volatilizing the solvent and, optionally, the volatile compound C (details of which will be described later) contained in the (wet) coating along with compound A, compound A, which was uniformly dispersed in the composition, segregates to the surface of the uncured film as the drying (volatilization) progresses, taking advantage of the polarity difference and compatibility with volatile compound C. This is achieved by curing the uncured film while the drying of the (wet) coating is almost complete and the state in which compound A is most effectively segregated onto the surface of the uncured film is maintained.

[0026] In the present invention, compound A may be any compound having a sulfonic acid group or a sulfonate salt group and at least one ethylenically unsaturated group. In the present invention, the ethylenically unsaturated group of compound A is preferably a vinyl group, an acryloyl group, or a methacryloyl group, more preferably an acryloyl group or a methacryloyl group. Examples of compound A include sodium or potassium salts of 2-((meth)acryloyloxy)ethanesulfonic acid, 3-((meth)acryloyloxy)propane-1-sulfonic acid, and acrylamido-tertiary-butylsulfonic acid. Preferred are linear alkylsulfonic acids having a (meth)acryloyloxy group and their salts, such as 2-((meth)acryloyloxy)ethanesulfonic acid and potassium 3-((meth)acryloyloxy)propane-1-sulfonate (potassium 3-sulfopropyl (meth)acrylate). Also usable are methacrylic sulfonic acid, sodium or potassium salt of p-styrenesulfonic acid, alkylsulfosuccinic acid alkenyl ether salt, polyoxyethylene (meth)acrylate sulfate salt, alkylsulfosuccinic acid alkenyl ester salt, glycerol-1-allyl-3-alkylphenyl-2-polyoxyethylene sulfate, etc. These compounds have sufficient reactivity with film-forming components including Compound B having three or more ethylenically unsaturated groups and a hydroxyl group in one molecule, as described below, and can impart high durability (strength, heat durability) to a cured film of the composition according to the present invention.

[0027] In the present invention, the term "hydrophilic component" refers to a substance that imparts hydrophilicity to a cured film of the composition, specifically a compound having hydrophilic properties.

[0028] Film-forming ingredients In the present invention, the film-forming component contains at least one compound B having three or more ethylenically unsaturated groups and a hydroxyl group in one molecule, and The composition according to the present invention contains 20% by weight or more of the The total hydroxyl value is greater than 15 mgKOH / g and less than 175 mgKOH / g, Its weight average molecular weight is 1000 [g / mol] or more, and The functional group equivalent weight of the ethylenically unsaturated group is less than 242 [g / eq].

[0029] In the present invention, the term "film-forming component" refers to a substance that physically constitutes a cured film, specifically a compound having two or more ethylenically unsaturated groups in one molecule.

[0030] The film-forming component contained in the composition of the present invention has three chemical properties: specific ranges of total hydroxyl value, weight-average molecular weight, and functional group equivalent weight of ethylenically unsaturated groups, and also has a specific range of concentration in the composition. It is believed that the intimate interaction of these four characteristics greatly contributes to the effect of obtaining a cured film that, when applied to the entire surface of a three-dimensional part, does not or suppresses sagging, especially on the vertical surface of the part, and maintains hydrophilicity and durability. The relationship between each feature of the film-forming component and the effect that is thought to be the main contributor thereto is explained below.

[0031] In the present invention, the film-forming component is contained in the composition at 20% by weight or more, and the weight-average molecular weight of the film-forming component is 1000 [g / mol] or more, which is believed to contribute at least to suppressing sagging of the composition of the present invention. The weight-average molecular weight of the film-forming component is preferably 1309 [g / mol] or more, and more preferably 1493 [g / mol] or more and 8875 [g / mol] or less. The weight average molecular weight is determined as follows. For the compound defined as the film-forming component, the weight average molecular weight is calculated using the following formula. TIFF0007823329000001.tif29168

[0032] In the present invention, the total hydroxyl value of the film-forming components is greater than 15 mgKOH / g and less than 175 mgKOH / g, which is believed to contribute to at least further enhancing the hydrophilicity of the cured film of the composition. The total hydroxyl value of the film-forming components is preferably 15 mgKOH / g or more and 123 mgKOH / g or less, and more preferably 23 mgKOH / g or more and less than 81 mgKOH / g. The hydroxyl value is determined as follows. For compounds defined as film-forming components, the average hydroxyl value is calculated using the following formula. TIFF0007823329000002.tif28168

[0033] In the present invention, it is believed that the lower the functional group equivalent of the ethylenically unsaturated group in the film-forming component, the more durable the cured film of the composition will be. According to one embodiment of the present invention, the functional group equivalent of the ethylenically unsaturated group in the film-forming component is greater than 103 [g / eq] and less than 242 [g / eq]. The functional group equivalent of the ethylenically unsaturated group in the film-forming component is preferably 194 [g / eq] or less, and more preferably 105 [g / eq] or more and 159 [g / eq] or less. This is believed to enable the durability of the cured film to be improved. The functional group equivalent of the ethylenically unsaturated group is determined as follows. For a compound defined as a film-forming component, the functional group equivalent of the ethylenically unsaturated group is calculated using the following formula. TIFF0007823329000003.tif29168

[0034] In the present invention, the ethylenically unsaturated group of the film-forming component is preferably a vinyl group, an acryloyl group, or a methacryloyl group, more preferably an acryloyl group or a methacryloyl group.

[0035] In the present invention, the film-forming component may consist solely of compound B, or may contain other compounds in addition to compound B. When the film-forming component consists solely of compound B, it is preferable that compound B has the above-mentioned characteristics.

[0036] In the present invention, the film-forming component may be a (meth)acrylate monomer (oligomer), a urethane-modified (meth)acrylate monomer (oligomer), or an epoxy-modified (meth)acrylate monomer (oligomer).

[0037] Examples of the (meth)acrylate monomer (oligomer) include 2-hydroxy-3-acryloyloxypropyl methacrylate, propoxylated ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, propoxylated bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, 1,10-decanediol diacrylate, and 1,6-hexanediol diacrylate. , 1,9-nonanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone-modified tris(2-acryloxyethyl) isocyanurate, pentaerythritol triacrylate, trimethylolpropane triacrylate, ditrimethylolpropane trimethacrylate, ethoxylated glycerin triacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethylolpropane trimethacrylate Examples of suitable acrylates include ethylolpropane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 2,2-bis[4-(methacryloxyethoxy)phenyl]propane, tricyclodecane dimethanol dimethacrylate, 1,10-decanediol dimethacrylate, 1,6-hexanediol methacrylate, 1,9-nonanediol methacrylate, neopentyl glycol methacrylate, glycerin dimethacrylate, trimethylolpropane trimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, glycerin triacrylate ethoxylate, dipentaerythritol polyacrylate, ethoxylated polypropylene glycol dimethacrylate, and polypropylene dimethacrylate.

[0038] Furthermore, examples of urethane (meth)acrylate oligomers (polymers) having two or more ethylenically unsaturated groups include phenyl glycidyl ether acrylate hexamethylene diisocyanate urethane prepolymer, phenyl glycidyl ether acrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, oligourethane acrylate, and carboxylic acid-containing urethane acrylate oligomer.

[0039] Furthermore, examples of epoxy (meth)acrylate oligomers (polymers) having two or more ethylenically unsaturated groups include cresol novolac epoxy acrylate and carboxylic anhydride-modified epoxy acrylate.

[0040] Among these, those that do not have hydrophilic functional groups such as hydroxyl groups, carboxyl groups, or ethylene oxide chains are particularly preferred because they have low compatibility with compound A and are effective in segregating compound A on the surface.Such film-forming components include propoxylated ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, propoxylated bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, 1,10-decanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, ethoxylated isocyanate, and the like. Nuric acid triacrylate, ε-caprolactone modified tris(2-acryloxyethyl) isocyanurate, trimethylolpropane triacrylate, ditrimethylolpropane trimethacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 2,2-bis[4-(methacryloxyethoxy)phenyl]propane, tricyclohexyl Examples of the acrylic acid esters include chlorodecane dimethanol dimethacrylate, 1,10-decanediol dimethacrylate, 1,6-hexanediol methacrylate, 1,9-nonanediol methacrylate, neopentyl glycol methacrylate, glycerin dimethacrylate, trimethylolpropane trimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, glycerin triacrylate ethoxylate, ethoxylated polypropylene glycol dimethacrylate, polypropylene dimethacrylate, phenyl glycidyl ether acrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, and dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer.

[0041] In the present invention, examples of compound B having three or more ethylenically unsaturated groups and a hydroxyl group in one molecule include pentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol tri(meth)acrylate, ethoxylated dipentaerythritol tetra(meth)acrylate, ethoxylated dipentaerythritol penta(meth)acrylate, polyglycerin monoethylene oxide poly(meth)acrylate, and (meth)acrylic acid ester copolymers.

[0042] Compound B1 In the present invention, the film-forming component preferably contains, as compound B, compound B1, which is an oligomer or polymer having an acrylic skeleton and having a hydroxyl group and three or more (meth)acrylate groups in the side chain. As such a compound B1, a compound B1-1 represented by the following formula can be used. [ka] In the above formula, m1 is preferably 1 to 1,000, and more preferably 1 to 200. m2 is preferably 5 to 1,000, and more preferably 10 to 200. The compound B1-1 preferably has a weight average molecular weight of 1,000 to 200,000, an ethylenically unsaturated functional group equivalent of 200 to 600 (g / eq), and a hydroxyl value of 50 to 290 (mgKOH / g).

[0043] According to a preferred embodiment of the present invention, compound B1-1 is, for example, the following compound: [ka] This compound has a weight average molecular weight of 10,500, an ethylenically unsaturated functional group equivalent of 314 (g / eq), and a hydroxyl value of 179 (mgKOH / g).

[0044] Furthermore, compound B1-2 represented by the following formula can be used as compound B1. [ka] In the above formula, n is preferably 5-1000, and more preferably 20-200. The compound B1-2 preferably has a weight average molecular weight of 1,000 to 200,000, an ethylenically unsaturated functional group equivalent of 200 to 250 (g / eq), and a hydroxyl value of 230 to 290 (mgKOH / g).

[0045] According to a preferred embodiment of the present invention, compound B1-2 is, for example: [ka] This compound has a weight average molecular weight of 13,000, an ethylenically unsaturated functional group equivalent of 218 (g / eq), and a hydroxyl value of 257 (mgKOH / g).

[0046] Compound B2 In the present invention, the film-forming component preferably further contains Compound B2, which is a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups in one molecule and no hydroxyl group. The inclusion of a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups in one molecule is thought to contribute at least to suppressing sagging of the composition and to impart durability to a cured film of the composition, thereby maintaining segregation of sulfonic acid groups to the surface of the component and contributing to maintaining hydrophilicity.

[0047] In the present invention, examples of compound B2 include pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate, propoxylated dipentaerythritol hexa(meth)acrylate, and propoxylated ditrimethylolpropane tetra(meth)acrylate.

[0048] In the present invention, the film-forming component may contain both compounds B1 and B2. In this case, the weight ratio of compounds B1 to B2 is preferably 1:0.5 to 29, more preferably 1:1 to 12. In the present invention, the weight ratio of B1 to compound B contained in the film-forming component is preferably 25 to 100% by weight, more preferably 40 to 100% by weight.

[0049] In the present invention, the composition contains 20% by weight of the film-forming component. This prevents the composition from sagging. The proportion of the film-forming component contained in the composition may be determined taking into consideration the coating method, film thickness, etc. Specifically, the content is preferably 25% by weight or more, and more preferably 30% by weight or more.

[0050] organic particles In the present invention, the organic particles are contained in the composition of the present invention in an amount of 1% by weight or more but less than 50% by weight, based on the film-forming components. The amount is preferably 5% by weight or more but less than 50% by weight, and more preferably 5% by weight or more but less than 40% by weight. By containing organic particles in this range, the occurrence of sagging of the composition of the present invention is further suppressed. Examples of organic particles include particles containing at least one type selected from acrylic, urethane, and polycarbonate. In the present invention, the organic particles are preferably acrylic particles. Acrylic particles have a high affinity with the acrylic main skeleton that constitutes the cured film of the composition of the present invention, thereby further suppressing the occurrence of sagging. Furthermore, the average particle diameter of the organic particles is preferably 1 μm or more but less than 50 μm, and more preferably 5 μm or more but less than 35 μm. By having the size of the organic particles within the above range, the occurrence of sagging of the composition of the present invention is further suppressed.

[0051] organic solvents The composition according to the present invention contains an organic solvent. By including an organic solvent, as described below, when a (wet) coating of the composition according to the present invention is dried and the organic solvent is evaporated, the sulfonic acid groups of the hydrophilic component can be segregated to the surface of the uncured film of the composition as the drying (volatilization) progresses, taking advantage of the polarity difference and compatibility with the volatile compound C described below. It is considered that segregation can be more reliably achieved by curing the uncured film while the drying is almost complete and the state in which the sulfonic acid groups are most segregated to the surface of the uncured film is maintained.

[0052] In terms of compatibility with other compounds contained in the composition of the present invention, examples of such organic solvents include, but are not limited to, alcohols such as methanol, ethanol, IPA (isopropanol), and n-butanol; cellosolves such as methoxyethanol and methoxypropanol; ketones such as acetone and MEK (methyl ethyl ketone); ethyl acetate, butyl acetate, THF (tetrahydrofuran), toluene, PEGMEA (propylene glycol monomethyl ether acetate), DMF (N,N'-dimethylformamide), and water. A mixture of multiple solvents may be used as needed. In the present invention, the composition preferably contains an amount of organic solvent that prevents the composition from dripping when applied to a substrate. In the present invention, the composition preferably contains 10 wt% or more, and more preferably 20 wt% or more, of the organic solvent. Furthermore, the composition preferably contains 80 wt% or less, and more preferably 70 wt% or less, of the organic solvent.

[0053] Other ingredients Volatile Compound C The composition according to the present invention preferably further comprises a volatile compound C having a smaller molecular weight than compound A and having one ethylenically unsaturated group and one hydrophilic group per molecule. Here, the volatile compound refers to a compound having a boiling point of 280°C or less, more preferably 260°C or less. The hydrophilic group of volatile compound C is preferably a hydroxyl group or a carboxyl group. Specific examples of volatile compound C include hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and its structural isomers, hydroxybutyl (meth)acrylate and its structural isomers, tetrahydrofurfuryl (meth)acrylate, (meth)acryloylmorpholine, N-vinylformamide, and (meth)acrylic acid. Among these, hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, and (meth)acrylic acid are preferred as volatile compound C from the viewpoint of compatibility with compound A.

[0054] A cured film of the composition according to the present invention can be obtained by applying the composition to a substrate, drying the (wet) coating on the substrate, and curing the uncured film, as described below. In this process, it is believed that the sulfonic acid group-containing compound A and the volatile compound C are sufficiently compatible with each other, so that when the (wet) coating is dried (by heating), compound C segregates together with compound A to the surface of the uncured film, allowing compound A to be uniformly distributed on the surface of the uncured film. Furthermore, it is believed that the volatile compound C remaining in the uncured film can easily polymerize with compound B when the uncured film is cured, thereby further increasing the strength of the cured film.

[0055] The molecular weight of volatile compound C is not particularly limited as long as it is smaller than the molecular weight of compound A, but is preferably 500 or less. When the molecular weight of volatile compound C is 500 or less, volatile compound C can be efficiently volatilized when a (wet) coating of the composition is dried. Furthermore, it is believed that as volatile compound C is volatilized together with the organic solvent, phase separation occurs between compound A containing sulfonic acid groups and compound B, which have been compatibilized by the inclusion of volatile compound C. It is believed that this phase separation promotes segregation of compound A containing sulfonic acid groups to the surface of the uncured film. The molecular weight of the volatile compound C is more preferably 100 to 200. This allows compound C to be volatilized without reducing the strength of the cured film when the uncured film of the composition is cured (polymerized).

[0056] polymerization initiator In the present invention, as described below, when an uncured film of the composition is cured (polymerized) by heat, the composition may contain a known radical polymerization initiator, curing catalyst, polymerization accelerator, etc. Furthermore, when an uncured film of the composition is cured (polymerized) by radiation, for example, active energy rays such as ultraviolet rays or visible light, the composition may contain a known photopolymerization initiator. An example of the photopolymerization initiator is Omnirad500 manufactured by IGM.

[0057] Method for producing a cured film of the composition according to the present invention A cured film of the composition according to the present invention can be prepared, for example, as follows.

[0058] Preparing the substrate First, a substrate to which the composition is to be applied is prepared. The substrate to which the hydrophilic composition of the present invention is to be applied is not particularly limited. Examples of the substrate material include metal, glass, resin, paper, and wood materials. Resins are preferred. Examples include thermosetting resins and thermoplastic resins. As the thermosetting resin, one or more resins selected from urea resin, melamine resin, phenolic resin, unsaturated polyester resin, epoxy resin, and silicone resin can be used. The thermoplastic resin may be one or more selected from polypropylene resin (PP), polyethylene resin (PE), polyacetal resin (POM), polybutylene terephthalate resin (PBT), polyvinyl chloride resin (PVC), polystyrene resin (PS), acrylonitrile-butadiene-styrene copolymer resin (ABS), polyphenylene sulfide resin (PPS), polyethylene terephthalate resin (PET), polymethyl methacrylate resin (PMMA), polyamide resin (PA), polyether ether ketone resin (PEEK), polytrimethylene terephthalate resin (PTT), polycarbonate resin (PC), and polytetrafluoroethylene (PTFE) (tetrafluoroethylene resin). In the present invention, a thermoplastic resin is preferably used as the resin. More preferably, the resin is one or more selected from PP, PE, POM, PBT, PVC, ABS, PPS, PET, PMMA, PA, and PC. Among these, one or more selected from PP, POM, PBT, ABS, and PMMA are even more preferred. Because the cured film of the composition according to the present invention has an acrylic main skeleton, substrates made of acrylic resin materials have good affinity (e.g., adhesion) with the cured film of the composition. The shape of the substrate to which the hydrophilic composition according to the present invention is applied is not particularly limited, and examples include flat and three-dimensional shapes. Since the hydrophilic composition according to the present invention is less likely to sag when applied to a substrate, it is preferably applied to a substrate having a three-dimensional shape.

[0059] In the present invention, the substrate is preferably a three-dimensional wet-related component. Since wet-related components are often used in environments where they are periodically exposed to water, forming a cured film of the hydrophilic composition of the present invention on the surface of the wet-related component improves drainage and drying properties, and can suppress the adhesion of stains such as water stains caused by residual water and oil.

[0060] Coating process The composition is then applied onto a substrate to form a (wet) coating of the composition. In the present invention, the composition can be applied to a substrate by any known method, such as brush coating, spray coating, dip coating, spin coating, or curtain coating.

[0061] Drying process The (wet) coating formed on the substrate is then dried to obtain an uncured film. At this time, it is sufficient to dry the (wet) coating, and if necessary, drying may be performed by heating. By (heating) drying, the organic solvent and volatile compound C contained in the (wet) coating are volatilized. During this process, as the organic solvent and volatile compound C volatilize from the (wet) coating (in other words, following the migration of the organic solvent and volatile compound C to the surface of the uncured film), the hydrophilic components that were uniformly dispersed in the (wet) coating before (heating) drying are thought to segregate to the surface of the uncured film by utilizing differences in polarity and compatibility with volatile compound C.

[0062] Heat drying can be performed using known methods such as drying with infrared rays or hot air. The heating temperature is usually from room temperature to 200°C, preferably from 35°C to 150°C, and more preferably from 40°C to 100°C. The drying time can be determined appropriately within a range that allows sufficient volatilization of the organic solvent and the volatile compound C, and can be determined depending on the material and size of the member to which the composition is applied. For example, the drying time can be within 30 minutes, preferably within 20 minutes, and more preferably within 15 minutes.

[0063] Curing process The uncured film is then cured. That is, compounds A, B, and C are copolymerized. The uncured film is preferably cured while the organic solvent and volatile compound C are sufficiently volatilized by a (heat) drying step, and the state in which the hydrophilic component is segregated to the uncured film surface is maintained. This is believed to ensure that the cured film has sulfonic acid groups segregated to its surface. As a result, it is believed that the cured film of the composition according to the present invention can also exhibit sufficient hydrophilicity.

[0064] As a method for curing the uncured film, known methods for polymerizing a compound containing an ethylenically unsaturated group, such as heat curing, active energy ray curing, or a combination thereof, can be used.

[0065] When polymerization curing is performed by thermal curing, a known polymerization initiator can be used. Furthermore, as the heating method, a known method of heating with infrared rays, hot air, or the like can be used, similar to the drying process of the (wet) coated material described above. In the case of thermal curing, the drying process and curing process of the (wet) coated material can be performed simultaneously in one process.

[0066] When polymerization and curing are carried out using active energy rays, examples of the radiation include visible light of 400 to 800 nm, ultraviolet light of 400 nm or less, and electron beams. However, ultraviolet light is preferred because it allows polymerization to be carried out easily and in a short time. When curing is carried out using ultraviolet light, a known photopolymerization initiator is used. The photopolymerization initiator is added in an amount of 0.01 to 20 mass% and preferably 1 to 10 mass% of the mass of the film-forming components contained in the composition. Examples of ultraviolet light sources include ultraviolet light such as low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, ultraviolet lasers, and sunlight. The irradiation atmosphere may be air or an inert gas such as nitrogen or argon.

[0067] The thickness of the cured film of the composition according to the present invention prepared as described above may be appropriately determined depending on the intended use and within a range in which the effects of the present invention can be achieved. For example, the thickness is preferably in the range of 0.1 μm to 300 μm, more preferably in the range of 1 to 100 μm, and even more preferably in the range of 1 to 20 μm.

[0068] water contact angle In the present invention, a cured film of the composition according to the present invention preferably has hydrophilicity. This hydrophilicity can be expressed as an index of the static contact angle with water. The static contact angle with water of a cured film of the composition according to the present invention can be measured, for example, by dropping a 1 μL water droplet onto the surface of the cured film at room temperature using a portable contact angle meter PCA-11 (manufactured by Kyowa Interface Science Co., Ltd.). Measurements are taken at several locations on the cured film surface, and the average value of the values ​​analyzed by the θ / 2 method can be used as the water contact angle. The water contact angle of a cured film of the composition according to the present invention is preferably 45° or less, more preferably 35° or less. When water adheres to the surface of a cured film having such a water contact angle, a rolling-up effect is achieved, resulting in a surface that is less susceptible to dirt adhesion. [Example]

[0069] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

[0070] Composition raw materials The following materials were prepared as raw materials for the composition.

[0071] <Hydrophilic component> ·Hydrophilic component 1 3-sulfopropyl potassium methacrylate (molecular weight: 246) represented by the following formula [ka]

[0072] ·Hydrophilic component 2 3-sulfopropyl potassium acrylate (molecular weight: 232) represented by the following formula [ka]

[0073] <Film-forming ingredients> Film-forming ingredient 1 The following formula: [ka] Dipentaerythritol hexaacrylate (corresponding to compound B2 in the present invention), which is a hexafunctional acrylic monomer having six acryloyl groups in one molecule, represented by the following formula: In the production process of the film-forming component 1, a small amount of a compound of the following formula: [ka] Dipentaerythritol pentaacrylate (corresponding to compound B in the present invention), which is a pentafunctional acrylic monomer having five acryloyl groups and hydroxyl groups in one molecule, represented by the formula: (molecular weight: 578, functional group equivalent of ethylenically unsaturated group: 96 (g / eq), hydroxyl value: 10 (mgKOH / g).

[0074] Film-forming ingredient 2 An acrylic acid ester copolymer having a hydroxyl group and an acryloyl group in the side chain, represented by the following formula (corresponding to compound B1-1 in the present invention; solid content: 40 wt %; weight average molecular weight: 10,500; functional group equivalent of ethylenically unsaturated group: 314 (g / eq); hydroxyl value: 179 (mgKOH / g)) [ka]

[0075] Film-forming ingredient 3 An acrylic acid ester copolymer having a hydroxyl group and an acryloyl group in the side chain, represented by the following formula (corresponding to compound B1-2 in the present invention; solid content: 40 wt %; weight average molecular weight: 13,000; functional group equivalent of ethylenically unsaturated group: 218 (g / eq); hydroxyl value: 257 (mgKOH / g)) [ka]

[0076] <particle> Organic particles 1: Acrylic particles (average particle size 6 μm) Organic particles 2: Acrylic particles (average particle size 10 μm) Organic particles 3: Acrylic particles (average particle size 19 μm) Organic particles 4: Acrylic particles (average particle size 35 μm) Organic particles 5: Acrylic particles (average particle size 46 μm) Inorganic particles 1: Silica particles (average particle size 20-25 nm) ·Inorganic particles 2: Silica nanoparticles (average particle diameter 20nm) Inorganic particle 3: silica glass (average particle size 10 μm)

[0077] <Organic solvents> 2-Methoxyethanol ·methanol ·ethanol ·acetone MEK (methyl ethyl ketone) Ethyl acetate Butyl acetate THF (tetrahydrofuran) ·toluene ·PEGMEA (Propylene glycol monomethyl ether acetate)

[0078] <Photopolymerization initiator> Omnirad500 (IGM) Omnirad500 is a mixture containing 50 wt% each of 1-hydroxycyclohexyl phenyl ketone (molecular weight: 204) represented by the formula below (left side) and benzophenone (molecular weight: 182) represented by the formula below (right side). [ka]

[0079] <Other ingredients> 2-Hydroxyethyl methacrylate (2-hydroxyethyl methacrylate, HEMA) (molecular weight: 130), represented by the following formula: [ka] Acrylic acid (AA) (molecular weight: 72) represented by the following formula: [ka] Methyl methacrylate (MMA) (molecular weight: 100) represented by the following formula: [ka]

[0080] Preparation of the composition A solution prepared by mixing the materials (above-mentioned hydrophilic component, film-forming component, organic solvent, other components, and photopolymerization initiator) shown in Tables 1 and 2 in the amounts (parts by weight) shown in the tables was stirred for 60 minutes with a stirrer. The particles shown in Tables 1 and 2 were added to this solution in the amounts shown in the tables, and the mixture was stirred for 5 minutes to prepare composition samples 1 to 52.

[0081] Evaluation 1: Evaluation of composition sagging (observation of uncured film) Using a sag tester (Anti-Sag Meter 1-6 mils, manufactured by BYK), composition samples (several selected from 1 to 52) were spray-coated onto a mount (Bikochart No. 2833, manufactured by BYK), and the mount on which the (wet) coating of the composition sample having a thickness of 38.1 μm was formed was placed vertically in a hot air drying oven (YAMATO Scientific DKN402) and left to stand for 10 minutes at a temperature of 70 ° C. The mount was then removed from the drying oven, and the uncured film was observed to evaluate whether sagging of the composition occurred after application and before curing, according to the following criteria. 〇: No sauce was found ×: Sauce was confirmed The results are shown in Table 3.

[0082] Preparation of a three-dimensional member having a cured film of the composition formed thereon An A4-sized acrylic plate (Acrylite EX manufactured by Mitsubishi Chemical) was processed using an acrylic plate bending machine (HA-400 manufactured by Taiyo Electric Industry Co., Ltd.) to produce a substrate with a top surface measuring approximately 210 x 260 mm, a vertical surface measuring 210 x 30 mm, an edge radius of 5 mm, and an angle of 90° between the top surface and the vertical surface. With the top surface of this substrate horizontal, each composition sample was spray-coated uniformly on the top surface, edge, and vertical surface to a film thickness of 20 μm. The substrate on which the (wet) composition sample was formed was quickly transferred to a hot air drying oven (YAMATO Scientific Co., Ltd. DKN402), and while maintaining the top surface horizontal, it was heated at a temperature of 70°C for 10 minutes to volatilize the solvent. Thereafter, the substrate was removed from the hot air drying oven, and the uncured film on the top surface, edge, and vertical surface was sprayed with an integrated light dose of 1000 mJ / cm. 2 The composition was cured by irradiating it with ultraviolet light (ANUP4154 manufactured by Panasonic Electric Works Co., Ltd.) in an amount of 1000 kJ / cm². As a result, sample components 1 to 52 were produced, each having a cured film of the composition formed on the top surface, edge, and elevational surface of the substrate.

[0083] evaluation The fabricated member samples 1 to 52 were evaluated as follows.

[0084] Evaluation 2: Evaluation of sagging of the composition (observation of the cured film) The appearance of the elevation of each component sample was visually inspected, and the presence or absence of non-uniformity in the cured film due to sagging of the composition after application and before curing was evaluated according to the following criteria. ○: The hardened film on the vertical surface was uniform △: There was some unevenness in gloss on the cured film surface of the vertical surface ×: The film thickness of the lower part of the cured film on the vertical surface was thick. The results are shown in Table 3.

[0085] For the member samples for which the result of Evaluation 2 was ×, it was not possible to carry out the evaluation of hydrophilicity and durability (Evaluations 3 to 5) described below.

[0086] Evaluation 3: Hydrophilicity evaluation The static contact angle with water was measured on the top and vertical surfaces of each component sample. Specifically, a portable contact angle meter PCA-11 (Kyowa Interface Science Co., Ltd.) was used to drop a 1 μL drop of water onto the top and vertical surfaces of each component sample at room temperature. Measurements were taken at five locations on each top and vertical surface of each component, and the average value of the values ​​analyzed using the θ / 2 method was used as the water contact angle value. Hydrophilicity was evaluated according to the following criteria. When the water contact angle is 35° or less, the surface is hydrophilic. When the water contact angle is 45° or less, the hydrophilicity is △ When the water contact angle is greater than 45°, the hydrophilicity is negative. The results are shown in Table 3.

[0087] Rating 4: Durability rating (rubbing resistance) 20 g of detergent containing an abrasive (Lion Bath Look Cleaning) was dropped onto the top and vertical surfaces of each component sample, and the surface was rubbed 100 times with a resin brush (TOTO EKL0034) under a load of 3 kg. After that, hydrophilicity evaluation (Evaluation 3) was performed. The obtained water contact angles were evaluated according to the following criteria. ○: The water contact angle is 45° or less, and the difference in the water contact angle before and after rubbing is less than 10° △: The water contact angle is 45° or less, and the difference in the water contact angle before and after rubbing is 10° or more ×: Water contact angle is 45° or more The results are shown in Table 3.

[0088] Rating 5: Durability rating (hot water resistance) Each component sample was immersed in warm water at 80°C for 24 hours. After that, the component sample was removed from the warm water, and the changes in the appearance of the top and elevational surfaces of the component sample were checked and evaluated according to the following criteria. ○: No change △: A slight change in appearance was observed when staring ×: Significant changes in appearance such as cloudiness were observed The results are shown in Table 3.

[0089] [Table 1]

[0090] [Table 2]

[0091] [Table 3]

Claims

1. a hydrophilic component including a compound A having a sulfonic acid group or a sulfonate salt group and at least one ethylenically unsaturated group in one molecule; a film-forming component containing a compound B having three or more ethylenically unsaturated groups and a hydroxyl group in one molecule; Organic particles, Organic solvents and A hydrophilic composition comprising: The film-forming component is The hydrophilic composition contains 20% by weight or more of the hydrophilic composition, The total hydroxyl value is greater than 15 mgKOH / g and less than 175 mgKOH / g, The weight average molecular weight is 1000 [g / mol] or more, and the functional group equivalent of the ethylenically unsaturated group is 194 [g / eq] or less, the organic particles are contained in the hydrophilic composition in an amount of 1% by weight or more and less than 50% by weight based on the film-forming component; The organic particles are acrylic particles. A hydrophilic composition comprising:

2. The hydrophilic composition according to claim 1 , wherein the ethylenically unsaturated group possessed by the compound A and the compound B is a (meth)acryloyl group.

3. 3. The hydrophilic composition according to claim 1, wherein the film-forming component comprises, as compound B, compound B1, which is an oligomer or polymer having an acrylic skeleton and having a hydroxyl group and three or more (meth)acrylate groups in its side chain.

4. 4. The hydrophilic composition according to claim 1, wherein the organic particles have an average particle size of 1 μm or more and 50 μm or less.

5. The hydrophilic composition according to any one of claims 1 to 4, wherein the film-forming component further comprises a compound B2 which is a polyfunctional (meth)acrylic monomer or oligomer having three or more functional groups in one molecule and no hydroxyl group.

6. The hydrophilic composition according to any one of claims 1 to 5, further comprising a volatile compound C having a smaller molecular weight than the compound A and having one ethylenically unsaturated group and a hydrophilic group in one molecule.

7. 7. The hydrophilic composition according to claim 4, wherein the organic particles have an average particle size of 5 μm or more and 35 μm or less.

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