JP7823329B2 - hydrophilic composition - Google Patents

Description

The present invention relates to a hydrophilic composition, and more specifically to a hydrophilic composition that can form an excellent film on the surface of a three-dimensional object.

One known method of imparting desired functionality to various components surrounding our living environment is to apply a coating film with the desired functionality to the surface of these components, and at the same time, development of coating compositions for forming such coatings is also underway.

For example, Japanese Patent Application Laid-Open No. 2014-233946 (Patent Document 1) describes a paint 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 with a volume average particle size of 35 μm. The paint is applied to the surface of a substrate (acrylic plate), dried by heating, and then cured by ultraviolet light. The paint is described as having excellent hydrophilicity, anti-slip properties, and durability due to the presence of sulfonic acid groups and acrylic resin beads on the surface (Examples 1-5, Table 1).

Meanwhile, Patent Document 1 lists examples of bathroom flooring, washbasin bowl materials, and other wet area components as base materials (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 sheet, 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.

Japanese Patent Application Laid-Open No. 2014-233946

The inventors have discovered that when a paint having the composition disclosed in Patent Document 1 is applied to the entire surface of a three-dimensional plumbing component, dripping of the paint occurs, particularly on the vertical surfaces. 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 great force or cleaning with an abrasive or alkaline detergent, the surface of the coating film containing sulfonic acid groups may be scraped off, and as a result, the hydrophilicity once achieved may not be maintained. Therefore, it is desirable for the resulting coating film to be highly durable.

The inventors attempted to increase the viscosity of the paint to prevent paint from dripping, 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 larger molecular weight. This approach was successful in preventing paint from dripping 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.

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

On the other hand, in order to prevent the paint applied to the surfaces of wet area components from dripping, we considered applying the paint separately to the top and bottom surfaces of the wet area components. This approach 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 applying additional paint to the seam could cause peeling, and leaving the seam as it was (unpainted) could result in dirt adhering, posing quality issues.

As such, it has traditionally been difficult to prevent paint from dripping when applied to the vertical surfaces of wet areas, particularly when paint can form a coating that is both hydrophilic and durable (strength, heat resistance, etc.).

The inventors have now discovered a paint composition that, when applied to the entire surface, particularly the vertical surfaces, of a three-dimensional plumbing 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 paint composition, they have confirmed that, when such a paint composition is applied to the entire surface, particularly the vertical surfaces, of a three-dimensional plumbing component, it suppresses the occurrence of sagging and forms a coating film that exhibits good hydrophilicity and durability. The present invention is based on this finding.

Therefore, the object of the present invention is to provide a composition that, when applied to the entire surface (especially the vertical surface) of a three-dimensional plumbing component, can suppress the occurrence of dripping and form a coating film that exhibits good hydrophilicity and durability.

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,
and an organic solvent,
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 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 based on the film-forming component.

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 by 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,
- Even during drying of the (wet) coated material, 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 coated material surface 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, and
The cured film obtained by curing the uncured film maintains high durability (strength) and is not easily scraped off, even when subjected to strong stresses such as rubbing with force or cleaning with an abrasive or alkaline detergent. This durability is thought to be due to the fact that the segregation of sulfonic acid groups to the surface of the component once achieved is maintained, thereby maintaining hydrophilicity.
In the above description, the meanings of the terms "cured film", "(wet) coating", "uncured film", and "segregation of sulfonic acid groups" will be explained later.

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. 1 is a perspective view showing a bathroom counter to which a hydrophilic composition according to the present invention can be applied.

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,
and an organic solvent.

Before describing each component contained in the hydrophilic composition of the present invention, we will first describe below the members to which the hydrophilic composition of the present invention can be applied.

The hydrophilic composition according to the present invention can be applied to the surfaces of various members. Preferably, it can be applied to the surfaces of members having a three-dimensional shape. More preferably, it can be applied to the surfaces of resin members having a three-dimensional shape.

The hydrophilic composition of the present invention can preferably be applied to the surface of a wet area component. In the present invention, wet area components refer to components used in toilets, bathrooms, kitchens, vanities, 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, vanities, 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 of the present invention is applied is a wet area component having a three-dimensional shape.

As examples of three-dimensional bathroom components, a bathroom counter or a bathtub rim will be explained using Figure 1. Figure 1 is a perspective view schematically illustrating an example of a bathroom. The 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. A bathtub 90 is provided within the bathroom space BS. The bathtub 90 has a rim, which users can grasp to enter and exit the bathtub. The bathroom 100 also has a faucet counter 11 and a sink counter 12 as counters 10. The faucet counter 11 dispenses water. The sink counter 12 is a relatively large, plate-shaped component on which items such as shampoo bottles and washbasins can be placed.

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

The hydrophilic composition of the present invention is preferably applied (e.g., painted) 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.

Each component contained in the hydrophilic composition according to the present invention is described below. Note that 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, the film obtained by curing the "composition" may also be referred to as the "cured film of the composition" or simply as the "cured film."

Hydrophilic Component In the present invention, the hydrophilic component comprises 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. By containing a sulfonic acid group or a sulfonate salt group, the cured film of the composition according to the present invention can exhibit hydrophilicity. Having hydrophilicity, for example, when the composition according to the present invention is applied to the surface of a wet-related component, is advantageous in that it improves drainage and drying properties, making it possible to suppress the adhesion of stains such as water stains due to residual water, and further suppresses the adhesion of oil. The cured film of the composition according to the present invention preferably contains more sulfonic acid groups or sulfonate salt groups on the surface than in the interior. In other words, it is preferable that the cured film of the composition according to the present invention has sulfonic acid groups segregated on the surface.

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, segregation of sulfonic acid groups on the surface of a cured film of the composition according to the present invention is believed to be achieved by, but not limited to, the following process. By drying the (wet) coating of the composition, i.e., by volatilizing the solvent and, optionally, 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 (wet) coating has almost completely dried and the segregation of compound A to the surface of the uncured film is at its most complete.

In the present invention, compound A may be any compound having a sulfonic acid group or 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, and 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). Additionally, 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. can also be used. These compounds are sufficiently reactive with film-forming components including Compound B, described below, which has three or more ethylenically unsaturated groups and a hydroxyl group in one molecule, and can impart high durability (strength, heat durability) to the cured film of the composition according to the present invention.

In the present invention, the term "hydrophilic component" refers to a substance that imparts hydrophilicity to the cured film of the composition. Specifically, it refers to a compound that has hydrophilic properties.

In the present invention, the film-forming component comprises at least one compound B having three or more ethylenically unsaturated groups and a hydroxyl group in one molecule, and is contained in an amount of 20% by weight or more in the composition according to the present invention;
The total hydroxyl value is greater than 15 mgKOH/g and less than 175 mgKOH/g,
The weight average molecular weight is 1,000 [g/mol] or more, and the functional group equivalent of the ethylenically unsaturated group is less than 242 [g/eq].

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

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 significantly contributes to the effect of producing a cured film that, when applied to the entire surface of a three-dimensional part, does not or suppresses sagging, particularly on the vertical surfaces of the part, and maintains hydrophilicity and durability. The relationship between each characteristic of the film-forming component and the effect that is thought to be the main contribution of each is explained below.

In the present invention, the film-forming component is contained in an amount of 20% by weight or more in the composition, and the weight-average molecular weight of the film-forming component is 1,000 g/mol or more, which is believed to contribute at least to the suppression of sagging of the composition of the present invention. The weight-average molecular weight of the film-forming component is preferably 1,309 g/mol or more, and more preferably 1,493 g/mol or more and 8,875 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.

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.

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, 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.

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, and more preferably an acryloyl group or a methacryloyl group.

In the present invention, the film-forming component may consist solely of compound B, or may contain components other than compound B. When the film-forming component consists solely of compound B, it is preferable that compound B has the characteristics described above.

In the present invention, (meth)acrylate monomers (oligomers), their urethane-modified counterparts, such as urethane (meth)acrylate monomers (oligomers), and their epoxy-modified counterparts, such as epoxy (meth)acrylate monomers (oligomers), can be used as film-forming components.

(Meth)acrylate monomers (oligomers), for example, 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, 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 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, polypropylene dimethacrylate, and the like.

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.

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

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 to the surface. Examples of 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, and ethoxylated isocyanate. 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 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.

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.

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.
In the above formula, m1 is preferably 1 to 1000, and more preferably 1 to 200. m2 is preferably 5 to 1000, 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).

According to a preferred embodiment of the present invention, the compound B1-1 is, for example, the following compound:
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).

Furthermore, compound B1-2 represented by the following formula can be used as compound B1.
In the above formula, n is preferably 5 to 1,000, and more preferably 20 to 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).

According to a preferred embodiment of the present invention, compound B1-2 is, for example:
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).

Compound B2
In the present invention, it is preferred that the film-forming component 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 on the surface of the component, and contributing to maintaining hydrophilicity.

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.

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 B1:B2 = 1:0.5 or more and 29 or less, and more preferably 1:1 or more and 12 or less. In the present invention, the weight proportion of B1 in compound B contained in the film-forming component is preferably 25% by weight or more and 100% by weight or less, and more preferably 40% by weight or more and 100% by weight or less.

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 can be determined taking into account the coating method, film thickness, etc. Specifically, it is preferable that the film-forming component be contained in an amount of 25% by weight or more, and more preferably 30% by weight or more.

Organic Particles In the present invention, the organic particles are contained in the composition of the present invention in an amount of 1 wt % or more but less than 50 wt % of the film-forming components. The amount is preferably 5 wt % or more but less than 50 wt %, and more preferably 5 wt % or more but less than 40 wt %. 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.

The composition according to the present invention comprises an organic solvent.By comprising an organic solvent, as will be described later, when the (wet) coating of the composition according to the present invention is dried and the organic solvent is evaporated, it is believed that the sulfonic acid group of the hydrophilic component can be segregated on the surface of the uncured film of the composition, taking advantage of the polarity difference and the compatibility with the volatile compound C described later, along with the progress of drying (volatilization).When drying is almost completed and the state in which the segregation of sulfonic acid group on the surface of the uncured film is most achieved is maintained, it is believed that segregation can be more reliably realized by curing the uncured film.

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. Multiple types of solvents may be mixed 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% by weight or more of the organic solvent, and more preferably 20% by weight or more. Furthermore, the composition preferably contains 80% by weight or less of the organic solvent, and more preferably 70% by weight or less.

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 possessed by 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 structural isomers thereof, hydroxybutyl (meth)acrylate and structural isomers thereof, 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.

As described below, 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. In this process, it is believed that sufficient compatibility between sulfonic acid group-containing compound A and volatile compound C allows compound C to segregate together with compound A to the surface of the uncured film when the (wet) coating is dried (by heating), allowing compound A to be uniformly distributed on the surface of the uncured film. Furthermore, it is believed that 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.

The molecular weight of the 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 when 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 formed when an uncured film of the composition is cured (polymerized).

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 Omnirad 500 manufactured by IGM.

Method for Producing a Cured Film of the Composition of the Present Invention A cured film of the composition of the present invention can be produced, for example, as follows.

Preparation of 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 types 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. Since 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. Furthermore, the shape of the substrate to which the hydrophilic composition according to the present invention is applied is not particularly limited, and examples thereof include planar 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.

In the present invention, the substrate is preferably a three-dimensional wet-related component. Because 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 buildup of stains such as limescale caused by residual water and the adhesion of oil.

Coating Step The composition is then coated 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.

Drying step: Next, the (wet) coating formed on the substrate is dried to obtain an uncured film. At this time, it is sufficient that the (wet) coating can be dried, and if necessary, it may be dried by heating. By (heating) drying, the organic solvent and volatile compound C contained in the (wet) coating are volatilized. Note that in this step, in parallel with the volatilization of the organic solvent and volatile compound C 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 component that was uniformly dispersed in the (wet) coating before (heating) drying is thought to segregate to the surface of the uncured film by utilizing the polarity difference and compatibility with the volatile compound C.

The heat drying method can be a known method using infrared rays or hot air, etc. The heating temperature is typically between room temperature and 200°C, preferably between 35°C and 150°C, and more preferably between 40°C and 100°C. The drying time can be determined appropriately within a range that allows sufficient evaporation of the organic solvent and volatile compound C, and can be determined depending on the material and size of the member to which the composition is applied. For example, it can be within 30 minutes, preferably within 20 minutes, and more preferably within 15 minutes.

Curing step: Next, the uncured film is cured. That is, compounds A, B, and C are copolymerized. The curing of the uncured film is preferably carried out while the organic solvent and volatile compound C are sufficiently volatilized by the (heating) drying step, and the state in which the hydrophilic component is segregated to the uncured film surface is maintained to the maximum extent. 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.

The uncured film can be cured using any known method for polymerizing a compound containing an ethylenically unsaturated group, such as heat curing, active energy ray curing, or a combination thereof.

When polymerizing and curing by heat curing, known polymerization initiators can be used. Furthermore, as with the drying process of the (wet) coated material described above, known heating methods such as infrared heating or hot air heating can be used. In the case of heat curing, the drying and curing processes of the (wet) coated material can also be carried out simultaneously in a single process.

When polymerization and curing are performed using actinic radiation, 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 for simple and rapid polymerization. When curing with ultraviolet light, a known photopolymerization initiator is used. The photopolymerization initiator is added in an amount of 0.01 to 20% by mass, preferably 1 to 10% by mass, of the film-forming components contained in the composition. UV sources include ultraviolet light from 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.

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

In the present invention, it is preferable that a cured film of the composition according to the present invention is hydrophilic. 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 value. 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.

The present invention will be specifically explained based on the following examples, but the present invention is not limited to these examples.

Raw Materials for the Composition The following materials were prepared as raw materials for the composition.

<Hydrophilic component>
・Hydrophilic component 1
3-sulfopropyl potassium methacrylate (molecular weight: 246) represented by the following formula

・Hydrophilic component 2
3-sulfopropyl potassium acrylate (molecular weight: 232) represented by the following formula:

<Film-forming ingredients>
・Film-forming component 1
The following formula:
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 represented by the following formula:
and 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)).

・Film-forming component 2
An acrylic acid ester copolymer having a hydroxyl group and an acryloyl group in a 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))

・Film-forming component 3
An acrylic acid ester copolymer having a hydroxyl group and an acryloyl group in a 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))

<Particle>
Organic particles 1: acrylic particles (average particle diameter 6 μm)
Organic particles 2: acrylic particles (average particle diameter 10 μm)
Organic particles 3: acrylic particles (average particle diameter 19 μm)
Organic particles 4: acrylic particles (average particle diameter 35 μm)
Organic particles 5: acrylic particles (average particle diameter 46 μm)
Inorganic particles 1: silica particles (average particle size 20-25 nm)
・Inorganic particles 2: Silica nanoparticles (average particle diameter 20 nm)
Inorganic particles 3: silica glass (average particle diameter 10 μm)

<Organic solvent>
・2-Methoxyethanol ・Methanol ・Ethanol ・Acetone ・MEK (Methyl Ethyl Ketone)
・Ethyl acetate ・Butyl acetate ・THF (tetrahydrofuran)
Toluene PEGMEA (propylene glycol monomethyl ether acetate)

<Photopolymerization initiator>
・Omnirad 500 (manufactured by IGM)
Omnirad 500 is a mixture containing 50 wt % each of 1-hydroxycyclohexyl phenyl ketone (molecular weight: 204) represented by the following formula (left side) and benzophenone (molecular weight: 182) represented by the following formula (right side).

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

Preparation of Compositions 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. To this solution, the particles shown in Tables 1 and 2 were added in the amounts shown in the tables, and the mixture was stirred for 5 minutes to prepare composition samples 1 to 52.

Evaluation 1: Evaluation of sagging of the composition (observation of uncured film)
Using a sagging 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 a (wet) coating of the composition sample having a thickness of 38.1 μm was formed was placed vertically in a hot air drying oven (DKN402, manufactured by Yamato Scientific Co., Ltd.) and left to stand for 10 minutes at a temperature of 70° C. Thereafter, the mount was removed from the drying oven, and the uncured film was observed to determine whether sagging of the composition occurred after application and before curing, and this was evaluated according to the following criteria.
◯: No sauce was observed. ×: Sauce was observed. The results are shown in Table 3.

Preparation of three-dimensional member having a cured film of composition formed thereon An A4 size acrylic plate (Acrylite EX manufactured by Mitsubishi Chemical Corporation) was processed using an acrylic plate bending machine (HA-400 manufactured by Taiyo Electric Sangyo Co., Ltd.) to prepare a substrate having 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, edge, and vertical surfaces to a film thickness of 20 μm. The substrate on which the (wet) coating of the composition sample was formed was quickly transferred to a hot air drying oven (YAMATO Scientific Corporation, DKN402), and while maintaining the top surface horizontal, it was heated at 70°C for 10 minutes to volatilize the solvent. The substrate was then removed from the hot air drying oven, and the uncured film on the top, edge, and vertical surfaces was irradiated with ultraviolet light (Panasonic Electric Works, ANUP4154) at an integrated light intensity of 1000 mJ/ ^cm2 to cure. As a result, component samples 1 to 52 were prepared in which a cured film of the composition was formed on the top, edge, and vertical surfaces of the substrate.

Evaluation The fabricated member samples 1 to 52 were evaluated as follows.

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 cured film on the vertical surface was uniform. Δ: There was some unevenness in gloss on the surface of the cured film on the vertical surface. ×: The film thickness of the lower part of the cured film on the vertical surface was thicker. The results are shown in Table 3.

For component samples that received an x in Evaluation 2, it was not possible to evaluate the hydrophilicity and durability (Evaluations 3 to 5) described below.

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 (manufactured by 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 of the top and vertical surfaces of each component, and the average value of the values analyzed using the θ/2 method was used as the water contact angle value, and 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 ×
The results are shown in Table 3.

Evaluation 4: Durability evaluation (rubbing resistance)
20 g of detergent containing an abrasive (Look Bath Cleaner, manufactured by Lion) was dropped onto the top and vertical surfaces of each component sample, and the surface was rubbed 100 times with a resin brush (EKL0034, manufactured by TOTO) while applying 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 was 45° or less, and the difference in the water contact angle before and after rubbing was less than 10°. △: The water contact angle was 45° or less, and the difference in the water contact angle before and after rubbing was 10° or more. ×: The water contact angle was 45° or more. The results are shown in Table 3.

Evaluation 5: Durability evaluation (hot water resistance)
Each component sample was immersed in warm water at 80° C. for 24 hours. Thereafter, the component sample was taken out of the warm water, and changes in the appearance of the top surface and the elevation of the component sample were checked and evaluated according to the following criteria.
◯: No change was observed. Δ: A slight change in appearance was observed upon close observation. ×: A significant change in appearance, such as cloudiness, was observed. The results are shown in Table 3.

Claims (7)

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,
and an organic solvent,
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 ;
A hydrophilic composition, wherein the organic particles are acrylic particles . The hydrophilic composition according to claim 1, wherein the ethylenically unsaturated groups possessed by compound A and compound B are (meth)acryloyl groups. 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. 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. 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. 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. The hydrophilic composition according to any one of claims 4 to 6 , wherein the organic particles have an average particle size of 5 µm or more and 35 µm or less.