JP6028660B2 - Hydrophilic coating composition, hydrophilic coating film, water-borne article, and method for producing hydrophilic coating film - Google Patents

Description

  The present invention relates to a hydrophilic coating composition excellent in antifogging property and antifouling property, a hydrophilic coating film, a water-borne article, and a method for forming a hydrophilic coating film.

  As a conventional hydrophilic coating composition containing an anionic hydrophilic group, there is one obtained by copolymerizing 2-sulfonylethyl acrylate Na and a bifunctional or higher acrylate compound (for example, see Patent Document 1). Patent Document 1 discloses an anion having a surface anion concentration (Sa) and a deep anion concentration (Da) in a coating film having at least one anionic hydrophilic group selected from a sulfonic acid group, a carboxyl group, and a phosphoric acid group. It is described that when the concentration ratio Sa / Da is 1.1 or more, hydrophilic property, antifouling property, antifogging property and antistatic property are imparted while having scratch resistance. It is also described that the ratio (molar ratio) of the substance amount of an acrylate compound having an anionic hydrophilic group and a compound having two or more (meth) acryloyl groups in one molecule is 15: 1 to 1:30. ing.

WO2007 / 064003

  In order not to impair the appearance such as hardness and transmittance of the coating film to be formed, it is preferable that the amount of the hydrophilic component is small. However, when the ratio (molar ratio) of the amount of acrylate compound having a sulfonic acid group which is an anionic hydrophilic group and two or more (bifunctional or more) acrylate compounds in one molecule is lower than 1:30, When the amount of the acrylate compound having a sulfonic acid group is reduced, there is a problem that hydrophilicity is not exhibited.

  The present invention has been made in view of the above problems, and a hydrophilic coating having high hydrophilicity while reducing the molar ratio of a hydrophilic component having an anionic hydrophilic group and an ethylenically unsaturated group to a film-forming component. PROBLEM TO BE SOLVED: To provide a hydrophilic coating composition capable of forming a film, a hydrophilic coating film containing the hydrophilic coating composition, a water-borne article on which the hydrophilic coating film is formed, and a method for forming the hydrophilic coating film With the goal.

In order to achieve the above object, the present invention provides a hydrophilic component comprising a compound (A) having at least one anionic hydrophilic group and at least one ethylenically unsaturated group in the molecule, and ethylenically unsaturated in the molecule. A film-forming component comprising a compound (B) having 4 or more groups and a compound (C) having one ethylenically unsaturated group in the molecule , wherein the compound (C) is hydroxylethyl methacrylate. Te, and a solubility parameter (SP value) of 23 (MPa ^/ cm ^{3) 1/2} or less of the film-forming components, the ratio of the substance amount of the hydrophilic component and a film-forming component is greater than 1:30 1: 450 or less Ah is, the functional group equivalent of the ethylenically unsaturated groups of the film-forming component (g / eq) is characterized in der Rukoto 125 or less.

According to the present invention, the solubility parameter (SP value) of the film-forming component is 23 (MPa / cm ³ ) ^1/2 or less, and the ratio of the amount of the hydrophilic component to the film-forming component is greater than 1:30 and 1 : By making it 450 or less, the hydrophilic component which consists of a compound (A) can be segregated on the coating-film surface efficiently. As a result, the formed hydrophilic coating film can maintain the hardness of the film-forming component and the coating film appearance while having high hydrophilicity, and is preferably used in a water environment where durability is required. I can do it.
According to the present invention, the compound (B) has 4 or more ethylenically unsaturated groups, and the functional group equivalent (g / eq) of the ethylenically unsaturated group of the film-forming component is 125 or less. Since a hydrophilic coating film having hydrophilicity and high alkali resistance can be formed, it can be particularly suitably used in a water environment exposed to an alkaline detergent or the like. Here, the functional group equivalent (g / eq) of the ethylenically unsaturated group of the film forming component is calculated by the molecular weight of each compound in the film forming component / the number of ethylenically unsaturated groups.

Moreover, in this invention, it is preferable that the ethylenically unsaturated group which a compound (A) and a compound (B ) have is either a vinyl group, an acryloyl group, or a methacryloyl group.

  Moreover, in this invention, it is preferable that a compound (A) is the following Chemical formula 1 or Chemical formula 2.

(In the formula, A represents —COO ⁻ , —PO ₄ ²⁻ , —HPO ₄ ⁻ , or —SO ₃ ^— . B represents H or CH _3. R represents an aliphatic hydrocarbon group having 2 to 20 carbon atoms. And may contain a phenylene group, an aliphatic cyclic group, an ether group, or an ester group, and M represents hydrogen, ammonium ion, alkali metal ion, or alkaline earth metal ion.)

According to the present invention, since the anionic hydrophilic group is —COO ⁻ , —PO ₄ ²⁻ , —HPO ₄ ⁻ , —SO ₃ ^— , the components constituting the scales such as silica, Na, and K in tap water are hydrophilic. Since these components do not adhere firmly to the surface of the water-resistant coating film, they can be easily removed even if these components adhere to them, and the hydrophilicity can be maintained for a long time.

In the present invention, the anionic hydrophilic group of the compound (A) is preferably —SO ₃ ^— or a salt thereof.

  According to the present invention, among anionic hydrophilic groups, a sulfonic acid group or a salt thereof has a high acid dissociation constant and is difficult to form a salt with a polyvalent metal ion. Therefore, a polyvalent such as Ca and Mg contained in tap water. Even when exposed to tap water containing metal ions, it is possible to further prevent the formation of scale.

  Moreover, in this invention, the hydrophilic coating film formed by hardening a hydrophilic coating composition can be formed.

According to the present invention, it is possible to segregate the hydrophilic component comprising the compound (A) on the surface of the hydrophilic coating film.

Moreover, the hydrophilic coating film of this invention can be used suitably for the surface of a water-based article. Here, water-filled articles refer to members used in toilets, bathrooms, kitchens, bathroom vanities, etc., such as bathroom wall materials, bathroom floor materials, bathroom window materials, bathroom door materials, shower booth wall materials, wash mirrors, Examples include, but are not limited to, bathroom vanities and bowls, artificial marble such as bathtubs, kitchen counters and kitchen sinks, range hood materials, toilet bowls, toilet seats, hot water cleaning toilet seats and cleaning nozzles, drain outlets, faucet fittings, etc. .

Since water-related products are regularly exposed to water, oil stains, and manure, the application of the hydrophilic coating composition of the present invention having an anionic hydrophilic group prevents the adhesion of stains and scales. Can suppress the occurrence of cloudiness.

Moreover, the manufacturing method of the hydrophilic coating film which concerns on this invention is the heating process which segregates the coating process which apply | coats a hydrophilic coating composition to a base material, and the hydrophilic component which consists of a compound (A) on the surface of a hydrophilic coating film. It can consist of a process and the hardening process which copolymerizes a hydrophilic component and a film-forming component by giving an active energy ray or heat.

  According to the present invention, it is possible to form a coating film having high hydrophilicity while maintaining the physical properties of the film-forming component. Moreover, it can be set as the coating film excellent in antifouling property and antifogging property.

It is the figure which showed the implementation and evaluation method of the drainage test.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

(Hydrophilic coating composition)
The hydrophilic coating composition of this invention contains the hydrophilic component and film forming component which consist of a compound (A). The film-forming component contains the compound (B), and more preferably contains the compound (C).

  In the hydrophilic coating composition of the present invention, the ratio of the amount of the hydrophilic component to the film-forming component is preferably greater than 1:30 and not greater than 1: 450. More preferably, it is more than 1:30 and 1: 200 or less, and more than 1:30 and 1: 100 or less. Thereby, a highly hydrophilic hydrophilic coating film can be formed while reducing the ratio of the amount of the hydrophilic component to the film-forming component.

Hydrophilic component The hydrophilic component of the present invention comprises the compound (A), and the compound (A) is a compound having an anionic hydrophilic group and at least one ethylenically unsaturated group in the molecule.

The compound (A) is represented by the above chemical formula 1 or chemical formula 2. In the formula, A represents an anionic hydrophilic group and represents —COO ⁻ , —PO ₄ ²⁻ , —HPO ₄ ⁻ , or —SO ₃ ^— . B represents H and CH ₃ . R represents an aliphatic hydrocarbon group having 2 to 20 carbon atoms, and may contain a phenylene group, an aliphatic cyclic group, an ether group, or an ester group. M represents hydrogen, ammonium ion, alkali metal ion, or alkaline earth metal ion. M is preferably a monovalent alkali metal, particularly preferably sodium or potassium salt.

Although the molecular weight of a compound (A) can be suitably used in the range which does not inhibit hydrophilicity, Preferably it is 200-1000, More preferably, it is 200-500. The smaller the molecular weight of the compound (A), the easier it is to segregate the compound (A) on the surface of the coating film during the heating process, and a coating film having sufficient hydrophilicity even if the molar ratio of the compound (A) is reduced. it can.

Examples of the anionic compound (A) represented by Chemical Formula 1 include 2-((meth) acryloyloxy) ethanesulfonic acid, 3-((meth) acryloyloxy) propane-1-sulfonic acid, and acrylamide tertiary butyl. Examples thereof include sodium and potassium salts of sulfonic acid.

Examples of the compound (A) represented by the chemical formula 2 include methallylsulfonic acid, sodium or potassium salt of p-styrenesulfonic acid, alkylsulfosuccinic acid alkenyl ether salt, polyoxyethylene (meth) acrylate sulfate ester salt, alkyl Examples thereof include sulfosuccinic acid alkenyl ester salts and glycerol-1-allyl-3-alkylphenyl-2-polyoxyethylene sulfate.

The compound (A) is particularly preferably a linear alkyl sulfonic acid having a (meth) acryloyloxy group and a salt thereof, 2-((meth) acryloyloxy) ethanesulfonic acid, 3-((meth) acryloyloxy ) Propane-1-sulfonic acid. Thereby, it can be set as a highly durable coating film which has sufficient reactivity with a film-forming component.

Film- forming component The film-forming component of the present invention contains a compound (B). The compound (B) is a compound having at least two ethylenically unsaturated groups in the molecule. The solubility parameter (SP value) of the film forming component is preferably 23 (MPa / cm ³ ) ^1/2 or less, and the functional group equivalent of the film forming component is preferably 125 g / eq or less.

  As an ethylenically unsaturated group of a compound (B), an acryloyl group, a methacryloyl group, and a vinyl group are preferable. Thereby, a coating film can be easily formed by heating or energy beam irradiation.

The molecular weight of the compound (B) is preferably 200 to 20000. This makes it possible to easily segregate the compound (A) on the surface of the coating film.

As a compound preferable as the compound (B), a (meth) acrylate monomer (oligomer) having at least two ethylenically unsaturated groups in the molecule, or a urethane (meth) acrylate monomer (oligomer) which is a urethane modified product thereof, An epoxy (meth) acrylate monomer (oligomer) which is an epoxy-modified product thereof can be mentioned.

Examples of the (meth) acrylate monomer (oligomer) having at least two ethylenically unsaturated groups in the molecule include 2-hydroxy-3-acryloyloxypropyl methacrylate, propoxylated ethoxylated bisphenol A diacrylate, and 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 tetra Acrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 2,2bis [4- (methacryloxyethoxy) phenyl] propane, tricyclodecane dimethanol di Methacrylate, 1,10-decanediol dimethac Relate, 1,6-hexanediol methacrylate, 1,9-nonanediol methacrylate, neopentyl glycol methacrylate, glycerin dimethacrylate, trimethylolpropane trimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetra Examples include methylene glycol diacrylate, glycerin triacrylate ethoxylate, dipentaerythritol polyacrylate, ethoxylated polypropylene glycol dimethacrylate, polypropylene dimethacrylate, and the like.

Examples of the urethane (meth) acrylate oligomer or urethane (meth) acrylate polymer having at least two ethylenically unsaturated groups in the molecule 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 Chromatography, oligourethane acrylate, and carboxylic acid-containing urethane acrylate oligomer.

  Examples of the epoxy (meth) acrylate oligomer (polymer) having at least two ethylenically unsaturated groups in the molecule include cresol novolac type epoxy acrylate and carboxylic acid anhydride-modified epoxy acrylate.

The functional group equivalent of the compound (B) is a value obtained by dividing the molecular weight of the compound (B) by the molecular weight of the ethylenically unsaturated group in the molecule of the compound (B). Compounds satisfying such functional group equivalents include pentaerythritol tetraacrylate (88 g / eq) dipentaerythritol tetraacrylate (105 g / eq), dipentaerythritol hexaacrylate (96 g / eq), trimethylolpropane triacrylate (99 g). / Eq), trimethylolpropane tetraacrylate (117 g / eq), 1,3,5-tris (2,2-diaacryloyloxymethyl-3- (2,2,2-triacryloyloxymethylethoxy) propylhexyl carbamate ) Isocyanurate (153 g / eq) (Shin Nakamura Chemical U15HA) and the like.

Among these, those having 6 or more functional groups in one molecule are particularly preferable in order to increase the durability of the coating film, and dipentaerythritol hexaacrylate (hexafunctional), 1,3,5-tris (2,2- There is diacryloyloxymethyl-3- (2,2,2-triacryloyloxymethylethoxy) propylhexyl carbamate) isocyanurate (15 functional).

Other compounds in the film-forming component The film-forming component of the present invention has a range that does not inhibit segregation of the hydrophilic component and does not exceed the limit of the SP value and functional group equivalent of the film-forming component. A compound (C) different from the compound (B) may be added.

  The compound (C) is a polymerizable compound having one ethylenically unsaturated group, and examples thereof include compounds represented by the following chemical formula 3 or chemical formula 4.

(In the formula, A ′ represents a hydroxyl group, a morpholino group, a furfuryl group or an amide group. B represents H or CH _3. R ′ represents an aliphatic hydrocarbon having 1 to 5 carbon atoms, a phenylene group or an ester group. And may contain an ether group.)
R ′ is an aliphatic hydrocarbon having 1 to 5 carbon atoms and may contain a phenylene group, an ester group, or an ether group. B: represents H, CH ₃ , and A ′ represents a hydroxyl group, a morpholino group, a furfuryl group, or an amide group.

As an example of the compound (C), hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and its structural isomer, hydroxybutyl (meth) acrylate and its structural isomer, tetrahydrofurfuryl (meth) acrylate, (meth) Examples include acryloylmorpholine and N-vinylformamide.

The compound (C) is preferably hydroxyethyl (meth) acrylate from the viewpoint of compatibility with the compound (A).

Although it will not specifically limit if the molecular weight of a compound (C) is smaller than a compound (A), 500 or less are preferable, More preferably, it is 100-200. The compound (C) is preferably a volatile compound. Here, the compound having volatility refers to a compound having a boiling range in the classification of volatile organic compounds by WHO of 260 ° C. or lower, or a saturated vapor pressure at 25 ° C. of 10 ⁻² kPa or higher, 100 ° C. It can be easily evaporated by the following heating.

  Since the compound (C) is a volatile compound having a molecular weight of 500 or less, it can be evaporated when heated. When the compound (C) is evaporated together with the solvent component after the hydrophilic coating composition is applied to the base material, the compound (A) and the compound (B) which are compatibilized by including the compound (C) are mixed. It is believed that phase separation occurs.

The amount of the compound (C) contained in the hydrophilic coating composition is the ratio of the amount of the compound (C) and the total amount of the compounds (A), (B) and (C). (Molar ratio) is preferably added in the range of more than 0.5: 1 and 0.99: 1. When the compound (C) is added in this range, a hydrophilic coating film having sufficient hydrophilicity can be formed even at a production site where the humidity is high. On the other hand, when the amount of the compound (C) is small, the moisture resistance effect is not sufficient, and when the amount is large, the compatibility with the compound (A) increases, and the compound (A) does not segregate on the hydrophilic coating surface. The hydrophilicity is insufficient. Further, the ratio (molar ratio) of the substance amount of the compound (C) and the sum of the substance amounts of the compound (A), the compound (B), and the compound (C) is larger than 0.5: 1 and greater than 0.00. More preferably, it is added in the range of 8: 1 or less. This is because the durability of the coating film decreases particularly when the abundance ratio of the compound (C) is excessively increased with respect to the compound (B) in the hydrophilic coating composition.

A preferred composition ratio of the compound (B) and the compound (C) is expressed as a substance amount ratio (molar ratio) of the compound (B) and the compound (C) and can be produced in a high humidity environment (C) / The substance amount ratio of the compound (B) is 1.1 or more and 100 or less, and in order to obtain a highly durable coating film, the substance amount ratio of the compound (C) / compound (B) is 1.1 or more and 2 It should be in the range of .5 or less.

(Solubility parameter of film forming component (SP value))
The solubility parameter (SP value) of the film-forming component of the present invention is preferably 23 (MPa / cm ³ ) ^1/2 or less, more preferably more than 21 and less than 22. Here, any of the known methods may be used for calculating the SP value, but in this embodiment, the value obtained by the Fedor method was used.

The SP value of the film-forming component in the case where the film-forming component contains a plurality of types of compounds (B) or a compound different from the compound (B), for example, the compound (C), The SP value was calculated as follows.

δ _mix : SP value of film-forming component φ _i : volume fraction of compound i in film-forming component δ _i : SP value of compound i in film-forming component Note that compound i in the film-forming component here is Compound (A) is not included.

Therefore, the SP value may be 23 or less by appropriately adjusting the ratio of the compound contained in the film-forming component, and there is no problem in using a compound (B) having an SP value exceeding 23.

(Functional group equivalent of film forming component)
The functional group equivalent of the film-forming component is more preferably 125 g / eq or less, and even more preferably 200 g / eq. Here, the functional group equivalent represents the molecular weight of the compound per functional group. The functional group equivalents of the film-forming component when a plurality of types are used as the film-forming component as the compound (B) or when other compounds such as the compound (C) are included are calculated as follows.

X _mix : film forming component functional group equivalent y _i : mole fraction of compound i x _i : functional group equivalent of compound i In addition, compound i in the film forming component here does not include compound (A).

Therefore, by appropriately adjusting the combination and ratio of the compounds in the film-forming component, there is no problem in using a compound (B) having a functional group equivalent exceeding 120 g / eq, but the ethylenic property of the compound (B). It is more preferable that the functional group equivalent of the unsaturated group is 200 g / eq or less. Thereby, it can be set as a highly durable coating film.

In order to apply to the water-circulating field where high alkali resistance is required, the compound (B) having 4 or more ethylenically unsaturated groups in the molecule is used as the compound (B) contained in the film-forming component, and It is preferable that the functional group equivalent of the film-forming component is 125 g / eq or less.

(solvent)
In the hydrophilic coating composition of the present invention, a solvent can be used in order to improve the wettability to the substrate and adjust the viscosity of the coating. From the viewpoint of compatibility between the hydrophilic component and the film-forming component, examples of the solvent include alcohols such as methanol, ethanol, IPA (isopropanol) and n-butanol, cellosolves such as methoxyethanol and methoxypropanol, and ketones such as acetone. , DMF (N, N′-dimethylformamide) and water are not particularly limited. Moreover, you may use a solvent in mixture of multiple types as needed.

(Polymerization initiator)
When the hydrophilic coating composition of the present invention is polymerized, a known radical polymerization initiator, catalyst, polymerization accelerator and the like are arbitrarily added within a range that does not inhibit hydrophilicity.

  When the hydrophilic coating composition of the present invention is copolymerized by radiation, for example, ultraviolet rays, a known photopolymerization initiator is used.

  Preferred photopolymerization initiators include, for example, Irgacure 651, Irgacure 184, Irgacure 500, Irgacure 2959, Irgacure 127, Irgacure 907, Irgacure 369, Irgacure 1300, Irgacure 819, provided by BASF. Irgacure 1800, Irgacure OXE01, Irgacure OXE02, Darocur 1173, Darocur TPO, Darocur 4265, and the like.

(Optional component)
Other optional ingredients such as UV absorbers, light stabilizers, antioxidants, leveling agents, antifoaming agents, thickeners, antisettling agents, dyes that control the design of paints, pigments, matting agents, etc. An agent can be added as long as the hydrophilicity of the paint is not impaired.

(Hydrophilic coating)
The hydrophilic coating film formed using the hydrophilic coating composition of the present invention preferably satisfies the following formula.
(Concentration of hydrophilic component at a depth of 50 nm from the coating film surface of the hydrophilic coating film) ÷ (Concentration of hydrophilic component on the coating film surface) × 100 ≦ 10 (%).
As the hydrophilic component exists only in the vicinity of the surface of the hydrophilic coating film, that is, a coating film in which the hydrophilic component segregates is formed, softening of the hydrophilic coating film due to the penetration of moisture into the hydrophilic coating film, Hydrolysis of the hydrophilic coating film due to the entry of the alkali component can be suppressed only at the extreme surface of the hydrophilic coating film, and a highly durable hydrophilic coating film can be obtained.

(Base material)
The substrate on which the hydrophilic coating composition of the present invention is applied is not particularly limited as long as it has physical durability in a wet environment. For example, it is widely applicable to resin members such as acrylic. In particular, it can be used for water-fitting members that are regularly exposed to water, such as water-fitting, bathroom wall materials, bathroom floor materials, bathroom window materials, bathroom door materials, shower booth wall materials, wash mirrors, and washstands. It can be widely used for artificial marble such as bathtubs, kitchen counters and kitchen sinks, range hood materials, toilet bowls, toilet seats, hot water cleaning toilet seats and cleaning nozzles, drain outlets, faucet fittings, etc.

(Manufacturing method of hydrophilic coating film)
The manufacturing method for forming a hydrophilic coating film from the hydrophilic coating composition of the present invention comprises a coating step of applying a hydrophilic coating composition to a substrate, and a hydrophilic component comprising the compound (A) as a hydrophilic coating composition. A heating step for segregating on the surface, and a curing step for copolymerizing the hydrophilic component and the film-forming component by applying an active energy ray or heat, preferably a pretreatment step for pretreating the base material; An application step of applying a hydrophilic coating composition to a substrate, a heating step of segregating the hydrophilic component comprising the compound (A) on the surface of the coating film to be formed, and applying an active energy ray or heat to the hydrophilic component. And a curing step for copolymerizing the film-forming component. It is preferable to mix a polymerization initiator with the hydrophilic coating composition, and an arbitrary polymerizable compound may be mixed. Here, between each process, there may be a moving process in which the base material is moved by a belt conveyor or the like, and a standby process that occurs to move to each process.

(Pretreatment process)
The pretreatment process may be omitted. If there is a problem with the adhesion between the hydrophilic coating film and the substrate or the coating property of the hydrophilic coating composition on the substrate, a primer layer may be provided on the substrate surface, or a known substrate before corona treatment, etc. Processing methods can be used.

(Coating process)
As a method for applying the hydrophilic coating composition of the present invention to a substrate, known methods such as brush coating, spray coating, dip coating, spin coating, and curtain coating can be used. The thickness of the hydrophilic coating film is in the range of 0.1 μm to 300 μm in order to have sufficient hydrophilicity and abrasion resistance and to generate good adhesion to the substrate without generating cracks. The thickness is preferably in the range of 1 to 100 μm, more preferably in the range of 1 to 20 μm. Accordingly, the hydrophilic coating composition is applied by adjusting the coating amount so that the film thickness is in the above range.

(Heating process)
As the heating method, a known method of heating with infrared rays or hot air can be used. The heating temperature is usually in the range of room temperature to 200 ° C, preferably 35 ° C to 150 ° C, more preferably 40 ° C to 100 ° C. On the other hand, if the heating time is too long, deformation of the substrate occurs when the substrate is a thermoplastic resin or the like. Furthermore, since mass productivity is also reduced, the preferred heating time is within 20 minutes, more preferably within 10 minutes. In addition, when the hydrophilic coating composition contains a compound (C) or a solvent, the heating time can be arbitrarily set. However, the heating time sufficient to volatilize the compound (C) and the solvent and dry the hydrophilic coating. Set.

(Curing process)
As a means for curing the hydrophilic coating composition applied to the substrate, a known method for polymerizing a compound containing an ethylenically unsaturated group such as thermal curing, active energy ray curing, or a combination thereof may be used. it can. A polymerization initiator is used when polymerization curing is performed by thermosetting. In the thermosetting, a known method of heating with infrared rays or hot air can be used as in the heating step.

  In the case of active energy ray curing, examples of the radiation include visible light of 400 to 800 nm, ultraviolet rays of 400 nm or less, and electron beams, and ultraviolet curing capable of performing polymerization in a short time is preferable. When curing with ultraviolet rays, a known photopolymerization initiator is used. A photoinitiator is added in 0.01-20 mass% of the mass of the polymeric compound contained in a hydrophilic coating composition, Preferably it is added in 1-10 mass%. Examples of the ultraviolet ray source include ultraviolet rays such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a xenon lamp, a gallium lamp, a metal halide lamp, an ultraviolet laser, and sunlight. The irradiation atmosphere may be air or an inert gas such as nitrogen or argon.

(Environmental humidity)
The hydrophilic coating composition of the present invention has an adverse effect on the appearance such as segregation of hydrophilic components and coating film transmittance especially in an environment where the relative humidity is high (for example, RH 80%) in the coating process, moving process and standby process. Since it may give, it is preferable that it is under a dry condition (RH50% or less).

  Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the examples.

( Reference Example 1)
As a compound (A) represented by Chemical Formula 1 as a hydrophilic component, 0.08 g of 3-sulfonylpropyl acrylate potassium salt (hereinafter abbreviated as SPA-K) is dissolved in 0.5 g of water, and then ethylene as a film-forming component. 7 g of dipentaerythritol hexaacrylate (NK ester A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd.), which is a compound (B) having two or more unsaturated unsaturated groups, and Irgacure 500 (manufactured by BASF) as a photopolymerization initiator. By stirring a solution of 14 g and 15 g of methoxyethanol as a solvent with a stirrer for 60 minutes, the molar ratio of the compound (A) to the compound (B) was 1: 35.2 (film-forming component (mol) / hydrophilic component). The hydrophilic coating composition of Reference Example 1 was prepared so that (mol) = 35.2).

  The obtained hydrophilic coating composition was applied to the surface of an acrylic plate having a thickness of 2 mm with a bar coater # 2. The acrylic plate coated with the hydrophilic coating composition was allowed to stand for 2 minutes in an environment with a relative humidity of RH 40% at 27 ° C. using a thermostatic chamber (NO DOOR α manufactured by AmeFrec), and then a hot air drying oven ( The solvent was volatilized under the conditions of a temperature of 70 ° C. and a drying time of 10 minutes using DKN402) manufactured by YAMATO Scientific.

After taking out from the hot air drying furnace, the hydrophilic coating composition is applied, and the dried acrylic board is irradiated with ultraviolet rays having an integrated light quantity of 1000 mJ / cm ² (ANUP4154 manufactured by Panasonic Electric Works), and the hydrophilic coating having a thickness of about 5 μm. A film was formed.

( Reference Example 2)
In Reference Example 2, a hydrophilic coating film was formed in the same manner as in Reference Example 1 except that the blending ratio was as shown in Table 2, and each evaluation test was performed.

( Reference Examples 3 to 6)
In Reference Examples 3 to 5, the compound (A) was 3-sulfonylpropyl methacrylate potassium salt (SPMA-K), and in Reference Example 6 the compound (B) was changed to pentaerythritol triacrylate (PETA) and shown in Table 2. A hydrophilic coating composition was prepared with such a formulation, and a hydrophilic coating film was formed in the same manner as in Reference Example 1.

( Reference Examples 7-9)
In Reference Examples 7 to 9, the compound (A) was changed to sulfonylethyl methacrylate sodium salt (SEM-Na), and the compound (B) was represented by using two types of polyglycerin monoethylene oxide polyacrylate (PG5009) and PETA. A hydrophilic coating composition was prepared with the formulation shown in 2 and a hydrophilic coating film was formed in the same manner as in Reference Example 1.

(Example 10)
Example 10 uses SPMA-K as the compound (A), A-DPH as the compound (B) having two or more ethylenically unsaturated groups as a film-forming component, and hydroxylethyl methacrylate as the compound (C). (HEMA) was added to prepare a hydrophilic coating composition with the formulation shown in Table 3, and a hydrophilic coating film was formed in the same manner as in Reference Example 1.

(Examples 11 to 13, Reference Examples 14 to 19)
In Examples 11 to 13 and Reference Examples 14 to 19, the hydrophilic compound (A) was changed to SPA-K with respect to Example 10, and a hydrophilic coating composition was prepared with the formulation shown in Table 3, A hydrophilic coating film was formed in the same manner as in Example 10.

( Reference Example 20)
In Reference Example 20, the compound (A) was changed to SPMA-K, the compound (B) was changed to (APG5054E), a hydrophilic coating composition was prepared with the formulation shown in Table 3, and Example 10 and Similarly, a hydrophilic coating film was formed.

( Reference Example 21)
In Reference Example 21, A-DPH was further added as Compound (B) to Reference Example 20, and a hydrophilic coating composition was prepared by blending as shown in Table 3. A hydrophilic coating film was formed in the same manner as in Example 10. did.

( Reference Example 22)
In Reference Example 22, the compound (B) was changed to ethoxylated bisphenol A diacrylate (EO addition mole number 3) (manufactured by Shin-Nakamura Chemical Co., Ltd .: ABE300) with respect to Reference Example 20 and blended as shown in Table 3. A hydrophilic coating composition was prepared, and a hydrophilic coating film was formed in the same manner as in Example 10.

( Reference Example 23)
In Reference Example 23, A-DPH was further added as Compound (B) to Reference Example 22, and a hydrophilic coating composition was prepared by blending as shown in Table 3. A hydrophilic coating film was prepared in the same manner as in Example 10. Formed.

(Example 24)
As a base material, a heat-polymerized base material is prepared by applying a thermosetting acrylic primer on a soft olefin sheet 100 mm × 100 mm having a concave portion having a width of 1.5 mm and a convex portion of 14 mm × 14 mm × 1 mm. did. Next, 4 g of a gloss adjusting agent obtained by dissolving polycarbonate particles having a median particle size of 6 to 7 μm in toluene was added to the hydrophilic coating composition of Example 10, and the bath was given a matte design by stirring with a stirrer. Floor paint was formulated. After applying this bathroom floor coating to the bathroom floor with a spray gun (Meiji Kikai Seisakusho Fine II) so that the film thickness after film formation is about 6 to 7 μm, as in Reference Example 1, a constant temperature and constant temperature chamber The film was allowed to stand at an ambient humidity of RH 40% at an air temperature of 27 ° C. for 2 minutes, and then heated and irradiated with ultraviolet rays to form a hydrophilic coating film.

(Comparative Example 1)
In Comparative Example 1, a hydrophilic coating film was formed in the same manner as in Reference Example 1 except that a hydrophilic coating composition was prepared with the formulation shown in Table 2.

(Comparative Examples 2 and 3)
In Comparative Example 2, SPMA-K as the compound (A), 2-propenoic acid, 1,1 ′-[(2-hydroxy1,3-propanediyl) bis [oxy (2-hydroxy-3, as the compound (B) 1-propanediyl)]] ester (manufactured by Kyoeisha Chemical Co., Ltd .: 80MFA) was used to prepare a hydrophilic coating composition with the formulation shown in Table 2, and a hydrophilic coating film was formed in the same manner as in Example 1.

(Comparative Examples 4 and 5)
In Comparative Examples 4 and 5, the hydrophilic component and the film-forming component were the same as in Reference Examples 7 to 9, and a hydrophilic coating composition was prepared with the formulation shown in Table 2, and a hydrophilic coating film was formed in the same manner as in Reference Example 1. did.

(Comparative Example 6)
In Comparative Example 6, a hydrophilic coating film was formed in the same manner as in Reference Example 1 except that A-DPH was used as a film-forming component without adding a hydrophilic component.

(Comparative Example 7)
In Comparative Example 7, the compound (A) is SPMA-K, the compound (B) is a cresol novolac epoxy acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd .: EA7420), the compound (C) is HEMA, and the composition shown in Table 3 is hydrophilic. An adhesive coating composition was prepared, and a hydrophilic coating film was formed in the same manner as in Example 10.

(Comparative Example 8)
In Comparative Example 8, a hydrophilic coating composition was prepared with the formulation shown in Table 3 with the compound (B) being 80 MFA relative to Comparative Example 7, and a hydrophilic coating film was formed in the same manner as in Example 10.

(Comparative Example 9)
In Comparative Example 9, a hydrophilic coating composition was prepared by blending compound (A) with SPMA-K, compound (B) with A-DPH and 80MFA, and compound (C) with HEMA shown in Table 3. A hydrophilic coating film was formed in the same manner as in Example 10.

(Comparative Example 10)
In Comparative Example 10, the same hydrophilic coating composition as in Comparative Example 9 was used, and a hydrophilic coating film was formed on the bathroom floor in the same manner as in Example 24.

The structures of compound (A), compound (B) and compound (C) used in Examples , Comparative Examples and Reference Examples are shown in Chemical Formulas 5 to 15. In addition, the molecular weight of the compound (A), the molecular weight of the compound (B) and the compound (C), the SP value calculated by the Fedor method, the functional group equivalent (g / eq), and the specific gravity (g / cm ³ ) are combined. Show.

Compound (A)

3-sulfonylpropyl acrylate potassium salt (SPA-K)
Molecular weight: 232.3

3-sulfonylpropyl methacrylate potassium salt (SPMA-K)
Molecular weight: 246.3

Sulfonylethyl methacrylate sodium salt (SEM-Na)
Molecular weight: 216.19

Compound (B)

Dipentaerythritol hexaacrylate (A-DPH)
Molecular weight: 579
SP value: 21
Functional group equivalent: 96.5
Specific gravity: 1.189

Pentaerythritol triacrylate (PETA)
Molecular weight: 298
SP value: 22.7
Functional group equivalent: 99.3
Specific gravity: 1.183

Polyglycerol monoethylene oxide polyacrylate (NK ECONOMER PG5009E manufactured by Shin-Nakamura Chemical Co., Ltd.)
Molecular weight: 1400
SP value: 21.4
Functional group equivalent: 200
Specific gravity: 1.183

2-propenoic acid, 1,1 ′-[(2-hydroxy1,3-propanediyl) bis [oxy (2-hydroxy-3,1-propanediyl)]] ester (80MFA)
Molecular weight: 348.4
SP value: 25.2
Functional group equivalent: 174.2
Specific gravity: 1.073

Polyglycerol monoethylene oxide polyacrylate (APG5054E)
Molecular weight: 3500
SP value: 20.1
Functional group equivalent: 388.9
Specific gravity: 1.073

Cresol novolac epoxy acrylate (EA7420)
Molecular weight: 3216
SP value: 24.7
Functional group equivalent: 247.4
Specific gravity: 1.136

Ethoxylated bisphenol A diacrylate (EO addition mole number 3) (ABE300)
Molecular weight: 469
SP value: 21
Functional group equivalent: 234.5
Specific gravity: 1.146

Compound (C)

Hydroxyethyl methacrylate (HEMA)
Molecular weight: 130.1
SP value: 23
Specific gravity: 1.073

  Evaluation of the hydrophilic coating film was performed as follows.

(Measurement of water contact angle)
The static contact angle with respect to water was measured by the θ / 2 method using a FACE contact angle meter CA-X150 (manufactured by Kyowa Interface Science) and the static contact angle 20 seconds after dropping a water droplet of 2 μL at room temperature. The measurement was carried out by measuring three points after forming the hydrophilic coating film, washing the hydrophilic coating film with distilled water and drying it, and after the chemical resistance test described later. Each measurement result used the average value of 3 times of each measurement.

(Anti-fouling (self-cleaning) test)
Hydrophobic pseudo-fouling in which carbon black (MA100 manufactured by Mitsubishi Chemical Co., Ltd.) was added to oleic acid so as to be 1 wt% was prepared, about 2 ml of the pseudo-fouling was dropped on the test specimen, and then washed with tap water. The contamination state was visually judged as follows.
○: When there is almost no adherence of contaminants on the surface of the test specimen △: When slightly adhered and remained ×: When clearly adhered and remained

(Anti-fogging test)
In the anti-fogging test, the surface on which the hydrophilic coating film was formed was placed vertically against the steam of the ultrasonic humidifier, the appearance was observed for 5 seconds, and visually judged as follows.
○: No cloudiness occurs △: Some cloudiness occurs ×: Cloudiness occurs

(Pencil hardness measurement)
The pencil hardness when dry and wet was measured according to the scratch hardness (pencil method) of JISK5600-5-4. In addition, at the time of drying here, the room temperature of 20 degreeC, the relative humidity of 50 RH% or less, and the time of wetness were immediately after taking out the hydrophilic coating film created in distilled water for 1 hour, and taking out.

(Alkali resistance test)
The following alkali resistance test was performed on the examples in which the hydrophilic coating film was formed.
After immersing in a 5 wt% sodium hydroxide aqueous solution for 48 hours, it was thoroughly rinsed with running water. After drying, the water contact angle, antifouling test and antifogging test of the hydrophilic coating film were carried out to evaluate the deterioration of performance.

Table 1 shows the abbreviations and weights of the compounds used in Examples , Comparative Examples and Reference Examples , and the volumes of Compound (B) and Compound (C). In Table 2, the abbreviations of the compounds used in Reference Examples 1 to 9 and Comparative Examples 1 to 6, the number of functional groups of each compound, the molar ratio of the compound (B) when the molar amount of the compound (A) is 1, The calculated SP value of the film-forming component, the film-forming component / hydrophilic component molar ratio, the functional group equivalent of the film-forming component, and the results of each evaluation test are shown.

Table 2 shows that each of the reference examples in which the molar ratio of the film-forming component to the hydrophilic component is 450 or less and the SP value of the film-forming component is 23 or less shows good hydrophilicity with a water contact angle of 30 ° or less. It was. Moreover, there was no change in pencil hardness at the time of drying or wetting, and a hydrophilic coating film showing good hydrophilicity but no decrease in hardness at the time of wetting was obtained. On the other hand, Comparative Examples 2 and 3 in which the SP value of the film forming component exceeded 23 had a water contact angle of more than 30 ° and did not show hydrophilicity. In addition, Comparative Examples 1, 4, and 5 in which the molar ratio of the film forming component to the hydrophilic component is 30 or less show good hydrophilicity with a water contact angle of 30 ° or less, while the pencil hardness at the time of drying or wetting is high. Declined. Further, Reference Examples 1 to 5 and Comparative Example 6 in which a hydrophilic coating film was formed using A-DPH, which is the same film forming component as Reference Examples 1 to 5 without adding a hydrophilic component, were both dry and wet. He always maintained the same pencil hardness.

In Table 3, the abbreviations of the compounds used in Examples 10 to 13, Reference Examples 14 to 23, and Comparative Examples 7 to 9, the number of functional groups of each compound, and the compound (B) when the molar amount of the compound (A) is 1. And the compound (C) molar ratio, the calculated SP value of the film-forming component, the film-forming component / hydrophilic component molar ratio, the functional group equivalent of the film-forming component, and the results of each evaluation test.

Table 3 shows that when a plurality of types of compounds (B) are used as the compound (B) or when the compound (C) is added to the film-forming component, the film-forming component and the hydrophilic property are the same as in Reference Examples 1-9. In Examples 10 to 13 and Reference Examples 14 to 23 in which the molar ratio of the components was 450 or less and the SP value of the film-forming component was 23 or less, all showed good hydrophilicity with a water contact angle of 30 ° or less. Moreover, there was no change in the pencil hardness at the time of drying or wetting, and a coating film showing good hydrophilicity and no decrease in hardness at the time of wetting was obtained.

In any of the examples and reference examples shown in Tables 2 and 3, the film-forming component contains a compound (B) having 4 or more ethylenically unsaturated groups, and the functional group equivalent in the film-forming component is In Reference Examples 1 to 5, Reference Examples 7 to 9, and Examples 10 to 13 of 125 g / eq or less, the hydrophilicity with a water contact angle of 30 ° or less was maintained even after the alkali resistance test.
In Examples and Reference Examples outside the above range, the water contact angle was remarkably increased and the hydrophilicity was deteriorated after the alkali resistance test.

(Measurement of surface and depth distribution of sulfur atom concentration derived from sulfonic acid or its salt in hydrophilic coating)
Next, for Reference Example 2, Reference Example 3, Reference Example 7, Comparative Example 1 and Comparative Example 5, measurement of the surface and depth distribution of the sulfur atom concentration (S) derived from the sulfonate group of the hydrophilic coating film is performed. went.

For the measurement, PHI5000 VersaProbe (manufactured by ULVAC-PHI) was used as an X-ray photoelectron spectroscopy (XPS) analyzer. The measurement of the depth distribution of the hydrophilic coating film was performed by measuring the surface exposed every specific sputtering time by Ar sputtering the hydrophilic coating film. Here, the surface of the hydrophilic coating film refers to a depth of less than 10 nm on the surface of the hydrophilic coating film in consideration of the X-ray penetration depth by the X-ray photoelectron spectrometer.

Device configuration Device: PHI5000 Versa Probe (ULVAC-PHI)
X-ray source: Monochromatic Al Ka (1486.6 eV)
Spectrometer: Electrostatic concentric hemispherical analyzer Amplifier: Multi-channel type (Multi-Channel Detector. 16ch parallel)
Measurement conditions Measurement energy: C1s, O1s, K2s, S2p, Na1s
Sputter depth profile X-ray beam diameter: 300 μmφ (75 W, 15 kV)
Analysis area: 300 μm × 300 μm
Signal capture angle: 45.0 °
Sputtering conditions Ion source: Ar ₂₅₀₀ ⁺
Acceleration voltage: 20 kV
Sample voltage: 100 nA
Sputtering area: 2mm x 2mm
Charge neutralization condition Neutralization gun 1.1V
Ion gun: 7V

The measurement was performed for Reference Example 2, Reference Example 3, Reference Example 7, Comparative Example 1 and Comparative Example 5.

The sulfur atom concentration (at%) is a ratio of the amount of sulfur atoms to the total amount of atoms detected at each depth from the coating film surface of the hydrophilic coating film.

The sulfur atom concentration (at%) on the surface of the hydrophilic coating film measured in Table 4 (hereinafter referred to as coating film surface S concentration) and the sulfur atom concentration (wt%) in the hydrophilic coating film (hereinafter referred to as in coating film) S ratio) and coating surface S concentration / coating film S concentration ratio (at% / wt%), results of water contact angle after alkali resistance test shown in Table 2 and Table 3, pencil hardness when wet Indicates. Here, the ratio of the coating film surface S concentration / the coating film S concentration indicates the degree of segregation of the sulfonic acid group derived from the hydrophilic component present in the coating film on the coating film surface.

Further, the S concentration in the coating film is calculated as follows.
(S concentration in coating film [wt%])
= (Weight concentration of compound (A)) × (sulfur atom weight / molecular weight of compound (A)) × 100
... Formula (3)

Since the weight concentration of the compound (A) used here is the weight concentration in the hydrophilic film, the weight of the solvent contained in the hydrophilic coating composition is not used for the calculation. Moreover, the sulfur atomic weight used 32.07.

Table 5 shows the results of measuring the sulfur atom concentration (at%) on the coating film surface and the sulfur atom concentration (at%) at each depth (nm) (hereinafter, each depth S concentration) with an X-ray photoelectron spectrometer. Indicates.
The depth from the coating film surface of each sample was calculated from the sputtering time and sputtering rate at the time of sputtering until reaching the substrate from the surface of the hydrophilic coating film. The sputter rates were calculated to be 135.1 nm / min for Reference Example 2, Reference Example 3 and Comparative Example 1, 63.6 nm / min for Reference Example 7, and 59.8 nm / min for Comparative Example 5, respectively.
Moreover, the ratio (%) of surface S concentration was obtained from the following equation.
(Ratio of surface S concentration [%]) = (each depth S concentration at each depth) / (each depth S concentration when the depth from the coating surface is 0 nm) × 100

From Table 4, the coating film of the reference example in which the ratio of the coating film surface S concentration / the S concentration in the coating film is 20 or more does not decrease the pencil hardness when wet, and the water contact angle after the alkali resistance test is 30 ° or less. Is maintained. On the other hand, a coating film having a coating surface S concentration / S coating concentration ratio of less than 20 has a pencil hardness when wet or a water contact angle of more than 30 ° after an alkali resistance test. In a humid environment or an environment exposed to an alkaline detergent.

Moreover, from Table 5, the sulfur atom concentration derived from the hydrophilic component in the coating film of the reference example is 54 nm deep from the coating film surface, the surface S concentration ratio of the coating film of the reference example 2 is 2.8%, and the reference example 3 In the coating film of 5.4%, in Reference Example 7, the depth is reduced to 2.4% at a depth of 64 nm, and the sulfur atom concentration derived from the hydrophilic component exists only in a very thin layer from the surface to about 50 nm. ing. On the other hand, the coating film of Comparative Example 2 has a surface S concentration ratio of 134% at a depth of 54 nm from the coating film surface, and the coating film of Comparative Example 7 has a surface S concentration ratio of 17.3% at 48 nm from the coating film surface. The presence of a certain amount of sulfur atoms was confirmed even at a depth of about 50 nm.

(Evaluation test when applied to bathroom floor)
Next, the example which apply | coated to the floor for bathrooms as a base material which apply | coats the hydrophilic coating composition of this invention is shown.

  The result of the evaluation test is shown as the time when the samples prepared in Example 24 and Comparative Example 10 were applied to the bathroom floor. As an evaluation test, a water contact angle, an antifouling test, and a drainage test were performed for evaluation. In addition, the measurement of the water contact angle in the bathroom floor was performed by dropping water droplets on the convex portions of the olefin sheet having irregularities. Here, when the water contact angle is less than 20 °, the water droplet dropped on the convex portion flows into the concave portion and it becomes difficult to determine the amount. Therefore, the evaluation was performed with the quantitative limit on the substrate as 20 °.

(Drainage test)
As shown in FIG. 1 (a), the four sides of the formed bathroom floor were covered with Kim Towel (registered trademark), and about 25 ml of tap water was poured over the entire bathroom floor (FIG. 1 (b)). . The drainage of the bathroom floor after pouring tap water was evaluated as follows.
○: The drained water is quickly and uniformly drained (FIG. 1 (a)).
Δ: A part of the flowed water remains on the floor, but is finally drained (FIG. 1 (b) → (a))
X: A portion of the water that has been passed through remains on the floor and is not drained. (Fig. 1 (c))

Table 6 shows the evaluation results of Example 24 and Comparative Example 10.

  As shown in Table 6, the bathroom floor of Example 24 has sufficient hydrophilicity, antifouling properties, and good drainage properties, but the bathroom floor of Comparative Example 10 has drainage performance because of its high water contact angle. However, the antifouling property was low. In particular, pseudo stains accumulated in the recesses could not be removed with water.

Claims (7)

A hydrophilic component comprising a compound (A) having at least one anionic hydrophilic group and at least one ethylenically unsaturated group in the molecule, and a compound having four or more ethylenically unsaturated groups in the molecule (B ) And a compound (C) having one ethylenically unsaturated group in the molecule ,
The compound (C) is hydroxylethyl methacrylate,
The solubility parameter (SP value) of the film-forming component is 23 (MPa / cm ³ ) ^1/2 or less, and the ratio of the amount of the hydrophilic component to the film-forming component is greater than 1:30 and 1: 450 or less. der is,
The film-forming functional group equivalent of the ethylenically unsaturated groups of component (g / eq) hydrophilic coating composition, characterized in der Rukoto 125 or less. The ethylenically unsaturated group which the said compound (A) and the said compound (B ) have is at least 1 sort (s ) chosen from either a vinyl group, an acryloyl group, and a methacryloyl group, The feature of Claim 1 characterized by the above-mentioned. Hydrophilic coating composition. The hydrophilic coating composition according to claim 2 , wherein the compound (A) is represented by the following chemical formula 1 or chemical formula 2.


(In the formula, A represents —COO ⁻ , —PO ₄ ²⁻ , —HPO ₄ ⁻ , or —SO ₃ ^— . B represents H or CH _3. R represents an aliphatic hydrocarbon group having 2 to 20 carbon atoms. And may contain a phenylene group, an aliphatic cyclic group, an ether group, or an ester group, and M represents hydrogen, ammonium ion, alkali metal ion, or alkaline earth metal ion.) The hydrophilic coating composition according to claim 3 , wherein the anionic hydrophilic group of the compound (A) is sulfonic acid or a salt thereof. The hydrophilic coating film formed by apply | coating the hydrophilic coating composition as described in any one of Claim 1 to 4 to the surface of a base material, and heating and hardening. A water-borne article in which the hydrophilic coating film according to claim 5 is formed on a surface of the surface material. An application step of applying the hydrophilic coating composition according to any one of claims 1 to 4 to a substrate;
A heating step of segregating the hydrophilic component comprising the compound (A) on the hydrophilic coating surface;
A curing step in which the hydrophilic component and the film-forming component are copolymerized by applying an active energy ray or heat,
A method for producing a hydrophilic coating film.