Condensation reactive microgel dispersion, its manufacturing method, hydrophilic treatment agent, hydrophilic treatment method, and hydrophilic film

Abstract

The present invention provides a condensation reactive microgel dispersion that can form a film having excellent water resistance and hydrophilicity when used together with a film-forming component and that has excellent storage stability. The present invention provides a condensation-reactive microgel dispersion comprising a microgel (G) comprising a core (C) containing a polymer of an ethylenically unsaturated monomer and a hydrophilic shell (S), and a medium (M) comprising water and / or a hydroxyl group-containing organic solvent, wherein the hydrophilic shell (S) provides dispersion stability to the core (C) in the medium (M), and the mass fractions of the core (C), hydrophilic shell (S), and medium (M) used to form the microgel (G) satisfy 0.05≦((C)+(S)) / (M)≦1, and the condensation-reactive microgel dispersion has a viscosity of [(NV 105℃ -NV 150℃ ) / NV 150℃ ] × 100 is 5% or more and 50% or less.

Description

[Technical Field]

[0001] The present disclosure relates to a condensation reactive microgel dispersion, a method for producing the same, a hydrophilization treatment agent, a hydrophilization treatment method, and a hydrophilic coating. [Background technology]

[0002] Conventionally, a technique for imparting functionality such as hydrophilicity by forming a coating on the surface of a substrate such as a metal material has been known. The coating is formed, for example, from a composition containing dispersible fine particles and a film-forming resin. As dispersible fine particles, hydrophilic crosslinked polymer fine particles that are intraparticle-crosslinked by a monomer component and dispersed in a medium have been disclosed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-003251 Summary of the Invention [Problem to be solved by the invention]

[0004] The hydrophilic crosslinked polymer microparticles disclosed in Patent Document 1 are intraparticle-crosslinked, which allows them to maintain their shape even in a medium containing a large amount of water or when heated. On the other hand, depending on the degree of intraparticle crosslinking of the dispersible microparticles, there is a problem that the formed film may become hydrophobic, and therefore it is necessary to appropriately control the intraparticle crosslinking. Furthermore, in order to form a film with excellent water resistance and solvent resistance by reacting the dispersible microparticles with a film-forming resin or the like, it is more important that a sufficient number of reactive groups remain in the dispersible microparticles by the time of reaction with the film-forming resin or the like than to maintain the shape of the microparticles.

[0005] The present disclosure has been made in view of the above, and aims to provide a condensation reactive microgel dispersion that can form a film with excellent water resistance and hydrophilicity when used together with a film-forming component, and that has excellent storage stability. [Means for solving the problem]

[0006] [1] The present disclosure relates to a condensation-reactive microgel dispersion having a microgel (G) composed of a core portion (C) containing a polymer of an ethylenically unsaturated monomer and a hydrophilic shell portion (S), and a medium (M) composed of water and / or a hydroxyl group-containing organic solvent, wherein the hydrophilic shell portion (S) imparts dispersion stability to the core portion (C) in the medium (M), and the mass fractions of the core portion (C), the hydrophilic shell portion (S), and the medium (M) used to form the microgel (G) satisfy 0.05≦((C)+(S)) / (M)≦1, and the ΔNV (%) of the condensation-reactive microgel dispersion, represented by the following formula (1), is 5% or more and 50% or less. ΔNV(%)=[(NV 105℃ -NV 150℃ ) / NV 150℃ ]×100 (1) In the above formula (1), NV 105℃ means the mass ratio (%) of the residue after heating the condensation reactive microgel dispersion at 105°C for 1 hour to the total mass before heating, and NV 150℃ means the mass ratio (%) of the residue after heating the condensation reactive microgel dispersion at 150°C for 1 hour relative to the total mass before heating.

[0007] [2] The condensation-reactive microgel dispersion according to [1], wherein the hydrophilic shell portion (S) is composed of an amphipathic compound, the amphipathic compound having a number-average molecular weight of 400 or more and 100,000 or less, the amphipathic compound is immobilized on the surface of the core portion (C) by chemical bonding and / or physical adsorption, the amphipathic compound has a polyoxyethylene structure represented by the following formula (2) in its molecule, and the mass fraction p of the polyoxyethylene structure relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) satisfies 0.1≦p≦0.5.

[0008] [ka]

[0009] In the above formula (2), n is 8 or more and 2000 or less.

[0010] [3] The condensation-reactive microgel dispersion according to [1] or [2], wherein the core portion (C) comprises a polymer of a monomer (a1) having one ethylenically unsaturated double bond, which is represented by the following formula (3), and the mass fraction r of the monomer (a1) relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) satisfies 0.5≦r≦0.9:

[0011] [ka]

[0012] In the above formula (3), R represents a hydrogen atom (H) or a methyl group (CH3).

[0013] [4] The condensation-reactive microgel dispersion according to any one of [1] to [3], wherein the condensation-reactive microgel dispersion further has an index I represented by the following formula (4) of 3 or more: I=(ΔNV-p×n 1 / 3 )×r (4) In the above formula (4), ΔNV, p, n, and r have the same meanings as those defined above.

[0014] [5] The condensation-reactive microgel dispersion according to any one of [1] to [4], wherein the monomer constituting the core portion (C) comprises a monomer (a1) having one ethylenically unsaturated double bond, and may optionally comprise a monomer (a2) other than the monomer (a1) having one ethylenically unsaturated double bond, and / or a monomer (a3) ​​having two or more ethylenically unsaturated double bonds, wherein the mass fraction of the monomer (a2) relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) is 0 or more and 0.2 or less, and the mass fraction of the monomer (a3) ​​relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) is 0 or more and 0.05 or less.

[0015] [6] A method for producing the condensation-reactive microgel dispersion according to any one of [1] to [5], comprising (co)polymerizing, in the medium (M), a compound constituting the hydrophilic shell portion (S) and a monomer constituting the core portion (C) using a radical polymerization initiator at a temperature of 60°C or higher and 120°C or lower.

[0016] [7] A hydrophilization treatment agent comprising the condensation-reactive microgel dispersion according to any one of [1] to [5] and an aqueous resin and / or a crosslinking agent, wherein the aqueous resin and / or the crosslinking agent has a reactive group that can react with the reactive group of the condensation-reactive microgel dispersion by heating.

[0017] [8] The reactive group of the condensation reactive microgel dispersion is a methylol group, The hydrophilic treatment agent according to [7], wherein the reactive group of the aqueous resin and / or the crosslinking agent is a hydroxy group.

[0018] [9] A hydrophilic treatment method comprising a step of applying the hydrophilic treatment agent according to [7] or [8] to a substrate.

[0019]

[10] The hydrophilization treatment method according to [9], wherein the substrate is a metal substrate.

[0020]

[11] A hydrophilic film formed by the hydrophilization treatment method described in [9]. [Effects of the Invention]

[0021] According to the present disclosure, it is possible to provide a condensation reactive microgel dispersion that can form a film with excellent water resistance and hydrophilicity when used together with a film-forming component and that has excellent storage stability. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present disclosure will be described, but the present disclosure is not limited to the following embodiments.

[0023] <Condensation reactive microgel dispersion> The condensation-reactive microgel dispersion according to this embodiment comprises a microgel (G) consisting of a core (C) containing a polymer of an ethylenically unsaturated monomer and a hydrophilic shell (S), and a medium (M) that is a dispersion medium consisting of water and / or a hydroxyl-containing organic solvent. This condensation-reactive microgel dispersion can be used, for example, with an aqueous resin and / or a crosslinker, which are film-forming components, to form a hydrophilic coating on the surface of a substrate such as a metal material. Because the microgel has high dispersibility in the treatment agent, it can form a hydrophilic coating with uniform performance.

[0024] In the condensation reactive microgel dispersion (hereinafter sometimes referred to as "dispersion"), when the microgel (G) is dispersed in a medium (M) consisting of water and / or a hydroxyl group-containing organic solvent, the reactive groups (e.g., methylol groups) of the core portion (C) are protected by the hydrophilic shell portion (S). This allows the reactive groups of the core portion (C) to be preserved for a long period of time in the dispersion. Therefore, the reactive groups of the core portion (C) can be sufficiently retained in the dispersion until the microgel (G) is reacted with the aqueous resin and / or crosslinking agent to form a hydrophilic coating. This allows the formation of a coating having a dense crosslinked structure with excellent water resistance, chemical resistance, solvent resistance, appearance, etc.

[0025] In the dispersion, the core (C) may be partially crosslinked, but does not necessarily retain its particle structure. Therefore, by appropriately controlling the degree of crosslinking, unreacted functional groups can be retained, improving physical properties such as the toughness and flexibility of the coating film. Furthermore, the new microgel, which is highly reactive and flexible in shape, efficiently reacts with the third component to form a film with a dense crosslinked structure and also has the property of enhancing the transparency of the film. Furthermore, the shell (S), which is expected to function as a coating for the core component in the treatment agent, is uniformly dispersed within the film once it is formed, allowing the chemical substances contained in the shell (S) to function as they are.

[0026] The activity of the core part (C), that is, the amount of reactive groups remaining in the core part (C), can be approximately estimated by the following formula (1). ΔNV(%)=[(NV 105℃ -NV 150℃ ) / NV 150℃ ]×100 (1)

[0027] In the above formula (1), NV 105℃ means the mass ratio (%) of the residue after heating the dispersion at 105°C for 1 hour to the total mass of the dispersion before heating, and NV 150℃means the mass ratio (%) of the residue after heating the dispersion at 150°C for 1 hour to the total mass of the dispersion before heating. 105℃ is close to the mass ratio (solid concentration) of the core part (C) and the hydrophilic shell part (S) to the total mass of the dispersion. 150℃ is approximately the mass ratio of the core part (C) and the hydrophilic shell part (S) to the total mass of the dispersion after components derived from the reactive groups are eliminated from the core part (C) (for example, HO may be eliminated by a condensation reaction). Therefore, ΔNV (%) is a numerical value that correlates with the amount of condensation reactive groups remaining in the core part (C).

[0028] The ΔNV (%) of the dispersion is 5% or more and 50% or less. A ΔNV (%) of 5% or more is expected to ensure that a sufficient amount of reactive groups remain in the core portion (C), thereby forming a coating with excellent water resistance, solvent resistance, etc. A ΔNV (%) of 50% or less ensures that the coating components do not evaporate and remain in sufficient amounts even when exposed to high temperatures, thereby enabling the desired functionality of the microgel to be favorably achieved. From the viewpoints of condensation reactivity and crosslinking effect, ΔNV (%) is preferably 5% or more and 30% or less, and more preferably 8% or more and 20% or less. ΔNV (%) can be controlled by adjusting the type and amount of reactive groups in the core portion (C) and the degree of protection of the core portion (C) by the hydrophilic shell portion (S).

[0029] The core part (C) is composed of a polymer of one or more ethylenically unsaturated monomers (hereinafter, sometimes referred to as "monomers"). Preferably, such a monomer essentially contains a monomer (a1) having one ethylenically unsaturated double bond. Examples of the monomer (a1) include monomers represented by the following formula (3). One type of monomer (a1) may be used, or two types may be used in combination.

[0030] [ka]

[0031] In the above formula (3), R represents a hydrogen atom (H) or a methyl group (CH3).

[0032] As shown in the above formula (3), the monomer (a1) has a polymerizable ethylenically unsaturated bond, a methylol group highly reactive with hydroxyl groups, and an amide group with hydrophilic properties. In the core portion (C) of the dispersion, the methylol groups in the polymerized monomer (a1) are protected by the hydrophilic shell portion (S), suppressing reaction with the medium (M). Therefore, a sufficient number of methylol groups are retained in the core portion (C) of the dispersion for the crosslinking reaction during film formation. During film formation, a strong chemical bond is formed by a dehydration condensation reaction between the methylol groups and the hydroxyl groups of the aqueous resin and / or crosslinking agent, and the amide groups impart favorable hydrophilic properties to the film.

[0033] The mass fraction r of the monomer (a1) relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) preferably satisfies the relationship 0.5≦r≦0.9. In this specification, each mass fraction can be determined based on the mass of each component used to form the microgel (G), i.e., the amount of the core portion (C) and the hydrophilic shell portion (S). A mass fraction r of 0.5 or greater allows the core portion (C) to contain a sufficient amount of reactive groups (methylol groups) and maintain sufficient condensation reactivity. If the mass fraction r exceeds 0.9, the mass of the hydrophilic shell portion (S) may be insufficient, resulting in problems such as an increase in the particle size of the microgel and aggregation, a loss of dispersion stability, or a thin coating layer that prevents long-term stability of the reactive groups. From the above perspectives, the mass fraction r is more preferably 0.55 or greater and 0.85 or less.

[0034] The ethylenically unsaturated monomer constituting the core portion (C) may optionally include at least one of the monomer (a2) and the monomer (a3). The monomer (a2) is a monomer other than the monomer (a1) having one ethylenically unsaturated double bond. The monomer (a3) ​​is a monomer having two or more ethylenically unsaturated double bonds. The compounds corresponding to the monomer (a2) and the monomer (a3) ​​may be used singly or in combination of two or more.

[0035] The monomer (a2) preferably has a characteristic functional group such as an amide group or a (meth)acrylic group. It is believed that the monomer (a2) can be uniformly dispersed in the treated film as a constituent of the microgel (G), and the characteristic functional group can be arranged in the film. Specific examples of the monomer (a2) include, but are not limited to, acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-(2-hydroxyethyl)acrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, N-vinylacetamide, N-vinylformamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N,N-dimethylacrylamide, N-vinylpyrrolidone, acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, glycidyl methacrylate, styrene, sodium vinyl sulfonate, sodium allyl sulfonate, sodium styrene sulfonate, and sodium 2-acrylamido-2-methylpropanesulfonate. It is particularly preferred to use at least one selected from the group consisting of acrylic acid, methacrylic acid, acrylamide, and N-(2-hydroxyethyl)acrylamide.

[0036] The mass fraction of the monomer (a2) relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) is preferably 0 or more and 0.2 or less.

[0037] The monomer (a3) ​​has two or more ethylenically unsaturated double bonds, which is thought to increase the internal crosslink density of the microgel (G), thereby improving the toughness of the treated film while maintaining the flexible shape change characteristic of the microgel.Specific examples of the monomer (a3) ​​include, but are not limited to, allyl methacrylate, N,N'-methylenebisacrylamide, ethylene glycol dimethacrylate, glycerol dimethacrylate, etc.

[0038] The mass fraction of the monomer (a3) ​​relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) is preferably 0 or more and 0.05 or less.

[0039] The hydrophilic shell portion (S) provides the core portion (C) with dispersion stability in the medium (M). The hydrophilic shell portion (S) is preferably composed of an amphipathic compound. The amphipathic compound preferably has a polyoxyethylene structure represented by the following formula (2) in its molecule and is immobilized on the surface of the core portion (C) by chemical bonding and / or physical adsorption.

[0040] [ka]

[0041] In the above formula (2), n is 8 or more and 2000 or less.

[0042] The amphiphilic compound has a polyoxyethylene structure represented by the above formula (2), and the mass fraction p of the polyoxyethylene structure relative to the total mass of the core portion (C) and hydrophilic shell portion (S) used to form the microgel (G) preferably satisfies 0.1≦p≦0.5. A mass fraction p of 0.1 or more can improve the dispersion stability of the microgel in the medium (M) and the storage stability of the crosslinking reactive groups in the core portion (C). A mass fraction p of 0.5 or less ensures the amount of reactive group components in the condensation-reactive microgel dispersion and also ensures a sufficient amount of components functioning as shell components. Furthermore, condensation reactivity is sufficiently maintained. From the viewpoints of dispersion stability and condensation reactivity, the mass fraction p is more preferably 0.15 or more and 0.45 or less.

[0043] The amphipathic compound preferably has a number average molecular weight of 400 or more and 100,000 or less. The amphipathic compound may have a polymerizable group, but may not have a polymerizable group. That is, the amphipathic compound may be immobilized on the surface of the core part (C) by chemical bonding via the polymerizable group, or may not have a polymerizable group and be immobilized on the surface of the core part (C) mainly by physical adsorption. Examples of the polymerizable group include groups having an ethylenically unsaturated double bond (such as an acryloyl group, a methacryloyl group, or an allyl group).

[0044] The amphiphilic compound may have a functional group (reactive group) other than the polymerizable group at the end of the polyoxyethylene structure. Examples of the functional group include an alkoxy group such as a methoxy group, a glycidyl group, and a hydroxy group.

[0045] The amphiphilic compound constituting the hydrophilic shell portion (S) may contain a compound other than the polyoxyethylene structure represented by the above formula (2). For example, it may contain an amphiphilic compound such as polyvinylpyrrolidone, polypropylene oxide, polyvinyl alcohol, or carboxymethyl cellulose. These compounds may be copolymers with compounds having a polyoxyethylene structure, or may be compounds consisting solely of compounds other than the polyoxyethylene structure.

[0046] When the core portion (C) is composed of a polymer of the monomer (a1) and the hydrophilic shell portion (S) is composed of an amphiphilic compound having a polyoxyethylene structure represented by the above formula (2), the dispersion preferably has an index I represented by the following formula (4) of 3 or more. I=(ΔNV-p×n 1 / 3 )×r (4)

[0047] In the above formula (4), ΔNV, p, n, and r have the same meanings as those described above. Formula (4) is a formula for correcting formula (1) and is an empirically derived formula. In formula (1), NV 150℃ does not necessarily indicate the value when only components derived from reactive groups are eliminated from the core part (C), and if one wishes to more accurately estimate the amount of reactive groups remaining in the core part (C), it is necessary to consider the influence of other decomposition products, etc., elimination from the core part (C). The above formula (4) identifies the components that make up the core part (C) and the hydrophilic shell part (S), and by considering the influence of these components, it is possible to calculate the index I, which has a high correlation with the amount of reactive groups remaining in the core part (C). When the index I is 3 or more, it is estimated that a sufficient amount of reactive groups remain in the core part (C), and therefore a coating having excellent water resistance, solvent resistance, etc. can be formed.

[0048] When the hydrophilic shell portion (S) contains k kinds of amphiphilic compounds having a polyoxyethylene structure represented by the above formula (2), the index I can be calculated by the following formula.

[0049]

number

[0050] In the above formula, n i p means the number of repeats of the polyoxyethylene structure in each compound. i means the mass fraction of the polyoxyethylene structure in each compound. ΔNV and r are the same as those defined above.

[0051] The medium (M) is composed of water and / or a hydroxyl group-containing organic solvent. Examples of the hydroxyl group-containing organic solvent include, but are not limited to, alcohols such as propanol and butanol, and alkylene glycol monoalkyl ethers such as ethylene glycol monobutyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and propylene glycol monopropyl ether.

[0052] In the dispersion, the mass fraction ((C) + (S)) / (M) of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) relative to the mass of the medium (M) is 0.05 or more and 1.0 or less. If the above ratio is less than 0.05, the concentration of dispersoid in the dispersion becomes too low, making it economically ineffective. If the above ratio exceeds 1.0, abnormalities such as gelation occur during polymerization, making it impossible to obtain a stable microgel dispersion. From the above viewpoints, the mass fraction ((C) + (S)) / (M) is preferably 0.10 or more and 0.70 or less.

[0053] The particle size of the microgel in the dispersion is not particularly limited, but for example, the average particle size measured by the cumulant method is 10 nm to 600 nm. The particle size can be measured, for example, by diluting the dispersion with water to a predetermined measurement concentration and using a concentrated particle size analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.).

[0054] The dispersion may contain any component other than those described above, as long as the effects of the present disclosure are not impaired.

[0055] <Method for producing condensation reactive microgel dispersion> The condensation-reactive microgel dispersion according to the above embodiment is preferably produced by (co)polymerizing the compound constituting the hydrophilic shell portion (S) and the monomer constituting the core portion (C) in the medium (M) using a radical polymerization initiator at a temperature of 60° C. to 120° C. The reaction temperature can be adjusted depending on the type of radical polymerization initiator.

[0056] If the copolymerization temperature is less than 60°C, the polymerization reaction will be insufficient, and if it exceeds 120°C, it will be difficult to control the reaction. The reaction time is usually 0.2 to 8 hours. If it is less than 0.2 hours, the polymerization reaction will be insufficient, and even if it exceeds 8 hours, the reaction will not change, which is economically disadvantageous.

[0057] The radical polymerization initiator is not particularly limited, and known radical polymerization initiators can be used. Examples of radical polymerization initiators include peroxides such as benzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, and t-butylperoxy-2-ethylhexanoate, and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, and 4,4'-azobis(4-cyanovaleric acid). These may be used alone or in combination of two or more. The amount used is usually within a range of 0.2 to 5% by mass based on the total amount of monomers.

[0058] In the copolymerization, a dispersant may be used in combination. Examples of the dispersant include dispersing resins such as polyvinylpyrrolidone, polyvinyl alcohol, and polycarboxylic acid, and various anionic, cationic, and nonionic surfactants.

[0059] In the above production method, when water and a hydroxyl-containing organic solvent are used in combination as the medium (M), water may be added after the copolymerization reaction. That is, water may be added after the compound constituting the hydrophilic shell portion (S) and the monomer constituting the core portion (C) are (co)polymerized in the hydroxyl-containing organic solvent as the medium (M) to produce a dispersion. In this case, water is not essential for the (co)polymerization reaction, but contributes to improving the dispersion stability of the hydrophilic shell portion (S) in the dispersion.

[0060] The above-mentioned production method may include other steps as long as the effects of the present disclosure are not impaired. For example, the monomers and radical polymerization initiators included in the present disclosure may undergo a neutralization or emulsification step using an acid, a base, a surfactant, or the like when they are added in order to adjust their reactivity.

[0061] <Hydrophilic treatment agent> The hydrophilic treatment agent contains the condensation reactive microgel dispersion according to the above embodiment and an aqueous resin and / or a crosslinking agent. The hydrophilic treatment agent can form a coating with excellent water resistance and hydrophilicity on the surface of a substrate made of a metal material or the like to be treated. Examples of metal materials include, but are not limited to, aluminum or an aluminum alloy.

[0062] The aqueous resin and / or crosslinking agent are film-forming components. The aqueous resin and / or crosslinking agent preferably have a reactive group capable of reacting with the reactive group (e.g., methylol group) of the dispersion. Examples of such reactive groups include hydroxyl groups and carboxyl groups. When the reactive group of the microgel is a methylol group, the reactive group of the aqueous resin and / or crosslinking agent is preferably a hydroxyl group.

[0063] The aqueous resin is not particularly limited as long as it is a hydrophilic resin, and examples thereof include polymers of unsaturated polymerizable monomers containing carboxy groups and / or hydroxy groups, natural polymer compounds containing carboxy groups and / or hydroxy groups or derivatives thereof, polyvinylpyrrolidone resins, aqueous polyester resins, aqueous polyamide resins, aqueous epoxy resins, aqueous polyurethane resins, aqueous phenolic resins, and aqueous amino resins.

[0064] Examples of the crosslinking agent include amino resins, epoxy resins, blocked isocyanates, phenolic resins, silane compounds such as silane coupling agents, silica compounds, aluminum compounds, and zirconium compounds. The crosslinking agent may have any structure, such as a sol or gel. The crosslinking agent may be used alone or in combination.

[0065] In the hydrophilic treatment agent, the blending ratio of the dispersion to the aqueous resin and / or crosslinking agent is preferably 1 / 99 to 80 / 20 in terms of solid mass ratio. If it is less than 1 / 99, the water resistance of the coating may decrease. If it exceeds 80 / 20, the processability may decrease. The blending ratio is more preferably 5 / 95 to 70 / 30.

[0066] The hydrophilic treatment agent may contain other components as long as the effects of the present disclosure are not impaired. Examples of other components include hydrophilic additives such as neutralizers for acids and bases, surfactants, colloidal silica, titanium oxide, and sugars; anti-rust additives such as tannic acid, imidazoles, triazines, triazoles, guanines, hydrazines, phenolic resins, zirconium compounds, and silane coupling agents; pigments such as inorganic pigments and organic pigments; sol compounds such as aluminum and silane; colorants, antibacterial agents, antifungal agents, dispersants, lubricants, deodorizers, photocatalytic compounds, fillers, and solvents.

[0067] <Hydrophilic treatment method> The hydrophilic treatment method using the hydrophilic treatment agent includes a coating step of coating the hydrophilic treatment agent onto a substrate (hereinafter referred to as a metal substrate) made of a metal material or the like to be treated. In addition to the above, the hydrophilic treatment method may also include a degreasing treatment step, a pretreatment step, a heating step, etc.

[0068] The degreasing treatment step is a step of degreasing the surface of the metal substrate with a known degreasing agent such as a solvent or an alkaline solution, etc. The pretreatment step is a step of applying a chemical conversion coating or a resin primer to the surface of the metal substrate after the degreasing treatment.

[0069] The coating step is a step of coating the hydrophilic treatment agent onto the surface of the metal substrate that has optionally been subjected to the degreasing treatment step and the pretreatment step. The coating method is not particularly limited, and examples thereof include roll coating, bar coating, dipping, spraying, and brush coating.

[0070] The heating step is a step of heating and curing the coating film formed on the surface of the metal substrate in the coating step. The heating temperature can be, for example, 120 to 350°C in an oven so that the temperature of the substrate reaches 100 to 200°C, and the heating time can be, for example, 3 seconds to 60 minutes.

[0071] <Hydrophilic film> The hydrophilic coating is a coating formed on a substrate such as a metal substrate by the hydrophilic treatment method. The coating has excellent water resistance and hydrophilicity. The hydrophilic coating of this embodiment is formed by mixing the components contained in the hydrophilic treatment agent, causing intermolecular interactions or chemical reactions. As a result, the resulting coating structure is complex, making it impossible or impractical to directly identify the hydrophilic coating by its structure. In other words, there are circumstances (impossible or impractical circumstances) in which it is impossible or impractical to directly identify the hydrophilic coating of this embodiment by its structure or properties. [Example]

[0072] The present disclosure will be described in more detail below based on examples, but the present disclosure is not limited to the following examples. However, Examples 14, 15, 16, and 18 are reference examples.

[0073] [Preparation of Condensation-Reactive Microgel Dispersion] Condensation reactive microgel dispersions according to the examples and comparative examples were prepared according to the formulations shown in Table 1. The values ​​indicating the content of each component in Table 1 are values ​​based on mass unless otherwise specified. "POE chain content (%)" in Table 1 refers to the mass fraction of polyoxyethylene structures in the amphiphilic compound. p, n, and n 1 / 3The definitions of are the same as those in the above embodiment. "Polymerizable group" means a group having an ethylenically unsaturated double bond. "Functional group" means a functional group at the terminal of a polyoxyethylene structure other than the above "polymerizable group". a1, a2, and a3 mean the monomer (a1), the monomer (a2), and the monomer (a3) ​​in the above embodiment, respectively. R means the substituent R in the above formula (3). The mass fraction means the mass fraction relative to the charged amount of the core portion (C) and the hydrophilic shell portion (S).

[0074] In Examples 11 and 12, two substances having a polyoxyethylene structure (POE chain) were used in combination as compounds constituting the hydrophilic shell portion (S). In Example 13, a substance having a polyoxyethylene structure (POE chain) and polyvinylpyrrolidone were used in combination as compounds constituting the hydrophilic shell portion (S). The mass fraction of polyvinylpyrrolidone relative to the charged amounts of the core portion (C) and hydrophilic shell portion (S) was 0.1.

[0075] [Table 1]

[0076] Details of the abbreviations in Table 1 are shown below: The initiator (radical polymerization initiator) used was appropriately selected from those disclosed in the above embodiment. BC: Ethylene glycol monobutyl ether MP: 1-methoxy 2-propanol GYL group: glycidyl group AA: acrylic acid HEAA: N-(2-hydroxyethyl)acrylamide AAm: acrylamide MAA: methacrylic acid AMA: Allyl methacrylate MBAA: N,N'-methylenebisacrylamide

[0077] The dispersions of each example and comparative example were synthesized according to the following procedure. A reaction vessel was charged with the medium (M), and the mixture was heated to the predetermined temperature shown in Table 2 while stirring under a nitrogen atmosphere. Monomers (a1) to (a3) ​​having an ethylenically unsaturated bond, which are components of the core part (C), were added to the compound constituting the shell part (S). A radical polymerization initiator was used in the amount shown in Table 1 relative to the monomers, and the reaction was allowed to proceed for the predetermined time shown in Table 2, thereby obtaining a dispersion. Note that in Comparative Example 5, the reaction time was set to 4 hours, but the reaction was stopped due to an increase in viscosity.

[0078] [NV measurement] The dispersions of each Example and Comparative Example were cooled after synthesis, diluted with water as necessary, and then removed. After filtering to remove coarse particles and aggregates, approximately 2 g of the filtrate was weighed into an aluminum cup, and the non-volatile content (NV%) of the filtrate was measured under two heating conditions: 105°C for 1 hour and 150°C for 1 hour. The obtained non-volatile content was measured as NV%. 105℃ , and N.V. 150℃ , and ΔNV (%) was calculated using the above formula (1). The results are shown in Table 2. ΔNV (%) over time was calculated in the same way as above, except that the samples were stored at 25°C for 180 days.

[0079] [Calculation of Index I] Based on the mass fraction p and the mass fraction r, the index I was calculated using the above formula (4) or the above mathematical formula. The results are shown in Table 2.

[0080] [Table 2]

[0081] [Preparation of hydrophilic treatment agent] The dispersions of the above Examples and Comparative Examples were added to an aqueous solution of polyvinyl alcohol (Kuraray Poval 25-100) at a solids ratio of 1:1 to obtain a hydrophilic treatment agent with a solids content of 10% by mass. For Example 17 in Table 3, the dispersion of Example 10 was used after storage at 25°C for 180 days. Similarly, for Example 18, the dispersion of Example 15 was used, and for Example 19, the dispersion of Example 1 was used, each after storage under the above conditions. For Comparative Example 6 in Table 3, only polyvinylpyrrolidone was used instead of the dispersion.

[0082] [Creating test panels] The above hydrophilic treatment agent was applied to a degreased aluminum plate (Al3000 series), baked and dried at 150°C for 30 minutes, and the dry coating amount was approximately 0.5 g / m 2 The following test panels were obtained. Note that the hydrophilic treatment agents of Comparative Examples 1 to 3 could not be subjected to the following tests because the coatings swelled.

[0083] [Film Remaining Rate Measurement] The weight of the test plate for each example and comparative example was measured to determine the weight of the coating. Each test plate was then stored under running water for two days, then removed from the running water and dried at 40°C, and the weight of the test plate was measured to determine the weight of the coating. The coating residual rate was calculated from the difference in weight of the coating before and after the test: ((weight before test) - (weight after test)) / (weight before test) x 100 (%). The results are shown in Table 3. A higher coating residual rate indicates better water resistance of the coating.

[0084] [Water wettability evaluation] As with the above film retention rate measurement, each test panel was stored under running water for two days, then removed from the running water. Five seconds after removal, the water wettability (the percentage of the area of ​​the coated surface that was wet when immersed in water) was visually evaluated according to the following evaluation criteria. A rating of ◯ was considered a pass. The results are shown in Table 3. (Evaluation criteria) 〇: 85% to 100% (full wetness) ×: 0% or more but less than 85%

[0085] [Water contact angle measurement] The water contact angle of the test plates according to each example and comparative example was measured using a contact angle meter (DSA20E, KRUSS). Furthermore, processing oil (Idemitsu, Daphne Punch Oil AF-8) was applied to each test plate, and the test plate was dried at 150°C for 5 minutes, and the water contact angle of the test plate was measured in the same manner. Furthermore, as in the above-mentioned film retention rate measurement, each test plate was stored under running water for 2 days, then removed from the running water, dried at 40°C, and the water contact angle (after water resistance) was measured in the same manner. The results are shown in Table 3.

[0086] [Table 3]

[0087] From the results of the above examples and comparative examples, it is clear that the dispersions of each example, when used together with a film-forming component, can form a film with excellent water resistance and hydrophilicity, and also have excellent storage stability.

Claims

1. a microgel (G) comprising a core portion (C) containing a polymer of an ethylenically unsaturated monomer and a hydrophilic shell portion (S); A condensation-reactive microgel dispersion having a medium (M) consisting of water and / or a hydroxyl group-containing organic solvent, The core part (C) contains a polymer of a monomer (a1) having one ethylenically unsaturated double bond, which is represented by the following formula (3): a mass fraction r of the monomer (a1) relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) satisfies 0.5≦r≦0.9; the hydrophilic shell portion (S) imparts dispersion stability to the core portion (C) in the medium (M), and is immobilized on the surface of the core portion (C) by chemical bonding and / or physical adsorption; The hydrophilic shell portion (S) is composed of an amphipathic compound, and the amphipathic compound has a polyoxyethylene structure represented by the following formula (2) in its molecule: The mass fractions of the core portion (C), the hydrophilic shell portion (S), and the medium (M) used to form the microgel (G) satisfy 0.05≦((C)+(S)) / (M)≦1, and the condensation-reactive microgel dispersion has a ΔNV (%) represented by the following formula (1) of 5% or more and 50% or less. ΔNV(%)=[(NV １０５℃ -NV １５０℃ ) / NV １５０℃ ]×100 (1) In the above formula (1), NV １０５℃ means the mass ratio (%) of the residue after heating the condensation reactive microgel dispersion at 105°C for 1 hour to the total mass before heating, and NV １５０℃ means the mass ratio (%) of the residue after heating the condensation reactive microgel dispersion at 150°C for 1 hour to the total mass before heating. 【Chemical 1】 In the above formula (2), n is 8 or more and 2000 or less. 【Chemistry 2】 In the above formula (3), R is a hydrogen atom (H) or a methyl group (CH ３ ) means

2. the amphiphilic compound has a number average molecular weight of 400 or more and 100,000 or less; 2. The condensation-reactive microgel dispersion according to claim 1, wherein a mass fraction p of the polyoxyethylene structure relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) satisfies 0.1≦p≦0.

5.

3. The condensation-reactive microgel dispersion according to claim 2, wherein the condensation-reactive microgel dispersion further has an index I represented by the following formula (4) of 3 or more and 26.3 or less. I=(ΔNV-p×n １／３ )×r (4) In the above formula (4), ΔNV, p, n, and r have the same meanings as those defined above.

4. The monomer constituting the core part (C) may, as necessary, contain a monomer (a2) having one ethylenically unsaturated double bond other than the monomer (a1), and / or a monomer (a3) ​​having two or more ethylenically unsaturated double bonds, a mass fraction of the monomer (a2) relative to the total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) is 0 or more and 0.2 or less; 2. The condensation-reactive microgel dispersion according to claim 1, wherein a mass fraction of the monomer (a3) ​​relative to a total mass of the core portion (C) and the hydrophilic shell portion (S) used to form the microgel (G) is 0 or more and 0.05 or less.

5. A method for producing the condensation reactive microgel dispersion according to claim 1, comprising: A method for producing a condensation-reactive microgel dispersion, comprising (co)polymerizing a compound constituting the hydrophilic shell portion (S) and a monomer constituting the core portion (C) in the medium (M) using a radical polymerization initiator at a temperature of 60°C or higher and 120°C or lower.

6. A composition comprising the condensation reactive microgel dispersion according to claim 1 and an aqueous resin and / or a crosslinking agent, The hydrophilization treatment agent, wherein the aqueous resin and / or crosslinking agent has a reactive group that can react with the reactive group of the condensation reactive microgel dispersion by heating.

7. the reactive group of the condensation reactive microgel dispersion is a methylol group, The hydrophilic treatment agent according to claim 6, wherein the reactive group of the aqueous resin and / or the crosslinking agent is a hydroxy group.

8. A hydrophilic treatment method comprising the step of applying the hydrophilic treatment agent according to claim 6 or 7 to a substrate.

9. The hydrophilization treatment method according to claim 8 , wherein the substrate is a metal substrate.

10. A hydrophilic film formed by the hydrophilization treatment method according to claim 8.

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