JP7428539B2 - Materials with surface treatment agents and surface treatment films - Google Patents

Description

The present invention relates to a surface treatment agent and a material having a surface treatment film.

In recent years, in various fields such as home appliances, automobiles, and building materials, as products have become more sophisticated, the performance requirements for the materials used have also increased. Conventionally, it has been known to treat materials with a surface treatment agent and coat them with a surface treatment film for the purpose of imparting corrosion resistance and coating adhesion. A surface treatment agent with high performance is required.

In Patent Document 1 (Patent No. 6118419), a zirconium compound, an aqueous epoxy resin having in its skeleton a carboxyl group-containing polymer containing a repeating unit derived from a carboxyl group-containing vinyl monomer, and a predetermined amount of hydroxycarboxylic acid are included. Surface treatment agents have been proposed. According to the surface treatment agent, it has excellent initial rust prevention properties without applying rust preventive oil, has excellent lubricity, and has excellent lubrication properties, and can be used even if surface treatment such as phosphate-based chemical conversion treatment or zirconium-based chemical conversion treatment is omitted. Patent Document 1 describes that a surface-treated metal material with excellent corrosion resistance and adhesion of a coating film can be manufactured.

In Patent Document 2 (Patent No. 6127198), a blocked isocyanate (A) having an isocyanate group blocked with a blocking agent and further having an isocyanurate structure and a polyalkyleneoxy chain, a hydroxy group, an amino group, A metal surface treatment liquid has been proposed that includes an organic resin (B) having at least one functional group selected from the group consisting of a sulfo group and a carboxy group. According to the metal surface treatment liquid, it is described in Patent Document 2 that a surface-treated metal material having excellent corrosion resistance, processability, chemical resistance, coating film adhesion, and post-painting corrosion resistance can be obtained.

Patent No. 6118419 Patent No. 6127198

By using the surface treatment agent described in the above patent document, it is possible to form a film with excellent durability (corrosion resistance and coating adhesion) on the flat surface of the material. However, according to the study results of the present inventor, the surface treatment agent described in the above-mentioned patent document is effective in improving the durability (corrosion resistance and paint film adhesion) of the processed parts of the material (the parts where the material is processed and unevenness is formed). There is still room for improvement in forming films with excellent properties.

The present invention was created in view of the above circumstances, and provides a surface treatment agent capable of forming a film with excellent durability (corrosion resistance and coating adhesion) not only on the flat surface of the material but also on the processed portion. That is the issue. Another object of the present invention is to provide a material having a surface-treated film, which is produced by surface-treating the material with such a surface-treating agent.

As a result of intensive studies to solve the above problems, the present inventors have discovered that an aqueous epoxy resin (A) having a structure in which one or more types of vinyl monomers are polymerized, The monomers may include a water-based epoxy resin (A) containing a vinyl monomer having a carboxyl group, and a blocked isocyanate (B) having an isocyanate group blocked by a blocking agent, an isocyanurate structure, and a polyalkyleneoxy chain. discovered that it is advantageous in obtaining a surface treatment agent capable of forming a film that is excellent in durability (corrosion resistance and coating adhesion) not only on the flat surface of the material but also on the processed portion, and thus completed the present invention. Ta.

The invention is exemplarily specified as follows.
[1]
A surface treatment agent containing an aqueous epoxy resin (A), a blocked isocyanate (B), and water,
The aqueous epoxy resin (A) has a structure in which one or more types of vinyl monomers are polymerized, and the one or more types of vinyl monomers include a vinyl monomer having a carboxyl group,
The blocked isocyanate (B) has an isocyanate group blocked by a blocking agent, an isocyanurate structure, and a polyalkyleneoxy chain.
Surface treatment agent.
[2]
The surface treatment agent according to [1], further containing a carbodiimide compound (C).
[3]
The surface treatment agent according to [1] or [2], which has a static surface tension value of 35 dyne/cm or less.
[4]
A material having a surface treatment film formed by bringing the surface treatment agent according to any one of [1] to [3] into contact with or on the surface of the material.

According to the present invention, it is possible to provide a surface treatment agent capable of forming a film having excellent durability (corrosion resistance and coating adhesion) on a processed portion of a material. Therefore, the present invention can contribute to improving the performance of materials used in various fields such as home appliances, automobiles, and building materials.

Hereinafter, embodiments of the present invention including a surface treatment agent and a material having a surface treatment film will be described in detail. Note that the present invention can be modified as desired without departing from the spirit of the present invention, and is not limited to the embodiments described below.

<1. Surface treatment agent>
According to one embodiment of the present invention, there is provided a surface treatment agent containing an aqueous epoxy resin (A), a blocked isocyanate (B), and water, wherein the aqueous epoxy resin (A) includes one or more types of The one or more types of vinyl monomers include a vinyl monomer having a carboxyl group, and the blocked isocyanate (B) has an isocyanate group blocked with a blocking agent, an isocyanurate structure. and a polyalkyleneoxy chain. The combined use of (A) and (B) is advantageous in obtaining a surface treatment agent that can form a film with excellent durability (corrosion resistance and coating adhesion) not only on the flat surface of the material but also on the processed portion. be.

(Aqueous epoxy resin (A))
The water-based epoxy resin (A) has a structure in which one or more types of vinyl monomers are polymerized. This structure includes structural units corresponding to one or more vinyl monomers. Further, the one or more kinds of vinyl monomers include a vinyl monomer having a carboxyl group (hereinafter also referred to as a carboxyl group-containing vinyl monomer). In this structure, the content of the structural unit corresponding to the vinyl monomer having a carboxyl group with respect to all the structural units corresponding to the vinyl monomer is not particularly limited, but is preferably 0.01 to 100 mol%, and 0.1 to 80 mol%. Mol% is more preferred.
The structure in which one or more kinds of vinyl monomers are polymerized may contain other structural units other than the structural units corresponding to the vinyl monomer having a carboxyl group. In other words, a structural unit corresponding to a vinyl monomer other than the vinyl monomer having a carboxyl group may be included. Other vinyl monomers will be detailed later.

The content of the polymerized structure of one or more types of vinyl monomers contained in the skeleton of the aqueous epoxy resin (A) is not particularly limited, but is preferably within the range of 0.1 to 30% by mass. Further, the acid value, which is an indicator of water dispersibility of the aqueous epoxy resin (A), is preferably 5 to 45 mgKOH/g, more preferably 17 to 40 mgKOH/g, and even more preferably 18 to 35 mgKOH/g. In this specification, the acid value is measured by a potentiometric titration method according to JIS K0070-1992.

The method for producing the aqueous epoxy resin (A) is not particularly limited, and any known method can be employed. For example, first, in the presence of optionally added amines, an epoxy resin, a glycidyl group-containing vinyl monomer, an amide group-containing vinyl monomer, an amino group-containing vinyl monomer, and a glycidyl ether of polyalkylene glycols are combined. A product X is produced by reacting at least one member selected from the group consisting of: Thereafter, a method of polymerizing the product X with a carboxyl group-containing vinyl monomer may be mentioned. In other words, the aqueous epoxy resin is a polymer obtained by reacting product X with a carboxyl group-containing vinyl monomer, and more specifically, in the presence of product It can be obtained by The carboxyl group-containing vinyl monomer may react with the product X by any reaction, but for example, the carboxyl group-containing vinyl monomer may react with the product react.

The type of epoxy resin used in producing product X is not particularly limited, as long as it contains an epoxy group. For example, an epoxy resin obtained by reacting a compound W selected from the group consisting of alkylene glycol and a compound having two or more hydroxyl phenyl groups in one molecule with epichlorohydrin is used. During the reaction, a catalyst may be added as necessary. In other words, the reaction may be carried out in the presence of a catalyst. As a catalyst, in addition to basic metal salts such as sodium hydroxide and sodium methoxide, amine compounds such as dimethylbenzylamine and tributylamine; and onium salts such as tetramethylammonium bromide, tetrabutylammonium bromide, and tetraphenylphosphonium chloride. Can be used. Further, during the reaction, a solvent (water or organic solvent) may be used as necessary.

As the glycidyl group-containing vinyl monomer used in producing the product X, any known compound containing a glycidyl group and a polymerizable vinyl group in its molecule can be used without particular limitation. Specific examples include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, and (meth)allyl glycidyl ether.
As the amide group-containing vinyl monomer used in producing the product X, any known compound containing an amide group and a polymerizable vinyl group in its molecule can be used without particular limitation. Specifically, acrylamide, N-butoxymethyl (meth)acrylamide, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, diacetone (meth)acrylamide, N- Examples include vinylformamide.
As the amino group-containing vinyl monomer used in producing the product X, any known compound containing an amino group and a polymerizable vinyl group in its molecule can be used without particular limitation. Specific examples include N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate.
In addition, the glycidyl ethers of polyalkylene glycols used in the production of product preferable. As the polyalkylene glycol, for example, known ones such as polyethylene glycol, polypropylene glycol, polybutylene glycol, etc. can be used.

The type of amine is not particularly limited, and various known amines can be used without particular limitation. Examples include alkanolamines, aliphatic amines, aromatic amines, alicyclic amines, aromatic nucleus-substituted aliphatic amines, and one or more of these can be appropriately selected and used.
To specifically show the types of amines, examples of alkanolamines include diethanolamine, diisopropanolamine, di-2-hydroxybutylamine, N-methylethanolamine, N-ethylethanolamine, N-benzylethanolamine, etc. can be mentioned. Examples of aliphatic amines include primary amines such as ethylamine, propylamine, butylamine, hexylamine, laurylamine, stearylamine, palmitylamine, oleylamine, and erucylamine, and diethylamine, dipropylamine, and dibutylamine. Examples include secondary amines. Further, examples of aromatic amines include toluidines, xylidines, cumidine (isopropylanilines), hexylanilines, nonylanilines, dodecylanilines, and the like. Examples of alicyclic amines include cyclopentylamines, cyclohexylamines, and norbornylamines. Furthermore, examples of the aromatic nucleus-substituted aliphatic amines include benzylamine, phenethylamine, and the like.

The conditions for producing product X are not particularly limited, and optimal conditions are selected depending on the materials used. The reaction temperature is not particularly limited, but is preferably from 30°C to 150°C, more preferably from 50°C to 150°C, from the standpoint that the reaction proceeds more efficiently. The reaction time is not particularly limited, but from the viewpoint of productivity, it is preferably 1 hour to 24 hours.

Examples of the carboxyl group-containing vinyl monomer include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid.

Other vinyl monomers may be used during the reaction with the carboxyl group-containing vinyl monomer. Examples of other vinyl monomers that are optional components that can be copolymerized with the carboxyl group-containing vinyl monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, and tert acrylate. - Acrylic acid esters such as butyl, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-hydroxy methacrylate Methacrylic acid esters such as ethyl and 2-ethylhexyl methacrylate; Styrenic vinyl monomers such as styrene, vinyltoluene, and α-methylstyrene; Others, such as vinyl acetate, β-hydroxyethyl acrylate, acrylonitrile, methacrylonitrile, etc. can be mentioned. These vinyl monomers can be used alone or in combination of two or more.

The conditions for the polymerization reaction of the product X and the carboxyl group-containing vinyl monomer are not particularly limited, and the optimum mode is selected depending on the compound used. For example, polymerization can be carried out at a reaction temperature of about 60 to 150° C. in the presence of a polymerization initiator.
The mass ratio between the amount of product X used and the total amount of carboxyl group-containing vinyl monomers and other vinyl monomers used (product It is preferable to adjust the acid value to the above-mentioned amount, but it is usually preferably within the range of 4 to 95.
Furthermore, the mass ratio of the carboxyl group-containing vinyl monomer in the vinyl monomer used (mass of the carboxyl group-containing vinyl monomer/total mass of the carboxyl group-containing vinyl monomer and other vinyl monomers) is not particularly limited, but is 0.01 to 0.8 is preferred.

(Blocked isocyanate (B))
Blocked isocyanate (B) has an isocyanate group blocked by a blocking agent (blocked isocyanate group), and further has an isocyanurate structure and a polyalkyleneoxy chain. Blocked isocyanate is a compound in which some or all of the isocyanate groups of an isocyanate compound are reacted with a blocking agent, and when heated, the protective group (residue of the blocking agent) dissociates and regenerates the isocyanate group. It is. Blocked isocyanates with lower dissociation temperatures regenerate isocyanate groups at relatively lower temperatures.

The blocking agent used to block (protect) the isocyanate group may be one that reacts with the isocyanate group, protects the isocyanate group, and dissociates upon heating to regenerate the isocyanate group, and its type is not particularly limited. However, compounds having one active hydrogen in the molecule are usually preferably used. For example, phenolic blocking agents (e.g., phenol, cresol), lactam-based blocking agents (e.g., caprolactam, valerolactam), oxime-based blocking agents (e.g., formamide oxime, acetamidoxime, methyl ethyl ketoxime), activated methylene-based blocking agents ( For example, diethyl malonate, dimethyl malonate), alcohol-based blocking agents (e.g., methanol, ethanol, ethylene glycol monobutyl ether), pyrazole-based blocking agents (e.g., 3,5-dimethylpyrazole), mercaptan-based blocking agents (e.g., butyl mercaptan), acid amide blocking agents (e.g. acetanilide, acetate amide), imidazole blocking agents (e.g. imidazole), amine blocking agents (e.g. diphenylamine, aniline), imine blocking agents (e.g. ethyleneimine) , urea-based blocking agents (eg, urea, thiourea). Among these, oxime-based blocking agents, active methylene-based blocking agents, alcohol-based blocking agents, and pyrazole-based blocking agents are preferred, and pyrazole-based blocking agents are more preferred. All the isocyanate groups may be blocked with one blocking agent, or two or more types of blocking agents may be used in combination.

The content of isocyanate groups blocked by a blocking agent in the blocked isocyanate (B) is not particularly limited, but the content of effective isocyanate groups in the blocked isocyanate (B) is 0 in the total mass of the blocked isocyanate (B). .5 to 10% by weight is preferable, and 1 to 7% by weight is more preferable.

The content of effective isocyanate groups refers to the content of isocyanate groups in the blocked isocyanate (B) after the blocking group that blocks the isocyanate groups is dissociated from the blocked isocyanate groups. The content (concentration) of effective isocyanate groups is measured according to the method specified in JIS K1603-1:2007.

Blocked isocyanate (B) has an isocyanurate structure (isocyanurate ring structure). The isocyanurate structure is a structure represented by the following formula (X). * represents the bonding position. The presence or absence of an isocyanurate structure in the blocked isocyanate (B) can be confirmed by isocyanate titration using the di-n-butylamine method, gas chromatography, refractive index, viscosity, infrared spectroscopy, etc.

The above-mentioned isocyanurate structure can be obtained by cyclizing and trimerizing isocyanate groups of various diisocyanates or triisocyanates.
As the diisocyanate, 1,4-tetramethylene diisocyanate, ethyl (2,6-diisocyanate) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4- or 2,4,4 - Aliphatic diisocyanates such as trimethylhexamethylene diisocyanate; 1,3- or 1,4-bis(isocyanatemethylcyclohexane), 1,3- or 1,4-diisocyanatecyclohexane, 3-isocyanate-methyl-3,5,5 - cycloaliphatic diisocyanates such as trimethylcyclohexyl isocyanate, dicyclohexylmethane-4,4'-diisocyanate, 2,5- or 2,6-diisocyanate methylnorbornane; m- or p-phenylene diisocyanate, tolylene-2,4- or 2-diisocyanate; , 6-diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,3-bis(2-isocyanate 2-propyl)benzene, naphthalene-1,5-diisocyanate, diphenyl-4,4'-diisocyanate, 4,4' -Diisocyanate Examples include aromatic diisocyanates such as 3,3'-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4'-diisocyanate, and diphenyl ether-4,4'-diisocyanate.
In addition, as the triisocyanate, aliphatic triisocyanates such as 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate 4-isocyanate methyl octane, and 2-isocyanate ethyl (2,6-diisocyanate) hexanoate; Alicyclic triisocyanates such as 5- or 2,6-diisocyanate methyl-2-isocyanate propylnorbornane; aromatic triisocyanates such as triphenylmethane triisocyanate and tris(isocyanate phenyl) thiophosphate.
The number of isocyanurate structures contained in the blocked isocyanate (B) is not particularly limited, but 1 to 10 is preferable, and 1 to 4 is more preferable, since the effects of the present invention are more excellent.

Blocked isocyanate (B) has a polyalkyleneoxy chain (eg, polyethyleneoxy chain, polypropyleneoxy chain). A polyalkyleneoxy chain is a chain having a structural unit (repeat unit) represented by the following formula (2).
Formula (2) - (LO) _n -
In the above formula (2), L represents an alkylene group. The number of carbon atoms contained in the alkylene group is not particularly limited, but is preferably from 2 to 10, more preferably from 2 to 4. The number of structural units (repeat units) represented by n is not particularly limited, but is preferably from 2 to 1,000, more preferably from 5 to 400, more preferably from 10 to 200, even more preferably from 15 to 150.

The molecular weight of the polyalkyleneoxy chain is not particularly limited, but is preferably from 100 to 10,000, more preferably from 200 to 5,000.

The content of polyalkyleneoxy chains in the blocked isocyanate (B) is not particularly limited, but is preferably 10% by mass to 70% by mass, more preferably 20% by mass to 60% by mass, based on the total mass of the blocked isocyanate (B).

The weight average molecular weight of the blocked isocyanate (B) is not particularly limited, but is preferably from 300 to 20,000, more preferably from 400 to 15,000, and even more preferably from 1,000 to 7,000. The weight average molecular weight of the blocked isocyanate (B) influences the physical properties of the formed film. In particular, the weight average molecular weight of the blocked isocyanate (B) is preferably high in terms of imparting excellent elasticity and strength to the film. Excellent elasticity and hardness not only give the coating mechanical resistance such as processing resistance, more specifically scratch resistance and abrasion resistance, but also chemical resistance such as chemical resistance. It is also effective for

The block isocyanate (B) is preferably a self-emulsifying block isocyanate. The self-emulsifying blocked isocyanate is intended to mean that the compound itself has an affinity for water and can be emulsified and dispersed in water. When the blocked isocyanate (B) is self-emulsified in the surface treatment agent, the particle size of the blocked isocyanate (B) particles in the surface treatment agent is preferably 0.01 μm to 1.00 μm, more preferably 0.05 μm to 0.05 μm. More preferably 50 μm. The particle diameter herein refers to the volume-based median diameter measured using a particle size distribution measuring device using a laser diffraction/scattering method.

Preferred embodiments of the blocked isocyanate (B) include embodiments having a structural unit represented by the following formula (1) and a structural unit represented by the above formula (2). * represents the bonding position.

In formula (1), each X independently represents a divalent hydrocarbon group. The number of carbon atoms contained in the divalent hydrocarbon group is not particularly limited, but is preferably from 1 to 20, more preferably from 2 to 20, even more preferably from 4 to 12.
Examples of the divalent hydrocarbon group include a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, or a combination thereof. The divalent aliphatic hydrocarbon group may be linear, branched, or cyclic. The cyclic type may be either monocyclic or polycyclic, and examples of monocyclic aliphatic hydrocarbon groups include cyclohexanediyl, and examples of polycyclic aliphatic hydrocarbon groups include adamantanediyl and norbornanediyl groups. Examples include.
Among these, the divalent hydrocarbon group includes an alkylene group having 1 to 6 carbon atoms, an aliphatic six-membered ring group which may be substituted with an alkyl group, or an aliphatic six-membered ring group which may be substituted with an alkyl group. Preferred examples include xylylene groups.

R ₁ represents a blocking agent residue. The residue of the blocking agent is intended to be a residue obtained by removing a hydrogen atom from the blocking agent that can react with an isocyanate group. The type of blocking agent is as described above. Among these, preferable examples include an alkylamino group having 3 to 8 carbon atoms, a 1,3-dicarbonyl group having 2 to 8 carbon atoms, and a pyrazole group having 2 to 8 carbon atoms.

The number of structural units represented by formula (1) in the blocked isocyanate (B) is not particularly limited, but is synonymous with the number of isocyanurate structures described above.

The content of the blocked isocyanate (B) in the surface treatment agent is not particularly limited, but the ratio of the mass (M _B ) of the block isocyanate (B) to the mass (M _A ) of the aqueous epoxy resin (A) (M _B /M _A ) is preferably blended into the surface treating agent so that it is 0.100 to 2.200, more preferably 0.200 to 1.200.

The method for producing the blocked isocyanate (B) is not particularly limited and any known method may be employed. For example, a polyisocyanate such as a diisocyanate is reacted to produce a polyisocyanate having an isocyanurate structure, and then a blocking agent is added. An example of this method is to add a polyalkyleneoxy compound to protect a part of the isocyanate group, and then to react by adding a polyalkyleneoxy compound. Note that the polyalkyleneoxy compound has a structural unit (repeat unit) represented by the above formula (2), and has a group capable of reacting with an isocyanate group such as a hydroxy group at the terminal (preferably both terminals). It is a compound.

When synthesizing a polyisocyanate having an isocyanurate structure, a catalyst (for example, a basic catalyst) may be used as necessary. Examples of the catalyst include trialkylbenzylammonium hydroxide; tetraalkylammonium hydroxide; alkyl metal salts of alkylcarboxylic acids such as tin, zinc, and lead; metal alcoholates such as sodium and potassium; and hexamethyldisilazane. Examples include aminosilyl group-containing compounds; Mannich bases; combined use of tertiary amines and epoxy compounds; and phosphorus compounds such as tributylphosphine. These may be used alone or in combination of two or more. In addition, when a basic catalyst is used as a catalyst, it is preferable to neutralize it with an acidic compound as necessary. The acidic compounds may be used alone or in combination of two or more.

The surface treatment agent for metal materials may contain a solvent for dissolving and dispersing the components and adjusting the concentration. The type of solvent is not particularly limited, and hexane, benzene, toluene, xylene, N-methylpyrrolidone, water (for example, deionized water), etc. can be used, and from the viewpoint of easier handling of the surface treatment agent. , it is preferred to use deionized water.
Further, the content of the solvent is preferably 30 to 95% by mass based on the total amount of the surface treatment agent.
Further, when water (eg, deionized water) is used as a solvent, it is preferable that the pH of the surface treatment agent for metal materials is 6 to 10. More preferred pH is 8-10.
In addition, it is preferable to use ammonia, carbonic acid, nitric acid, organic acid, etc. to adjust the pH.

(Carbodiimide compound (C))
It is preferable to incorporate a carbodiimide compound (C) into the surface treatment agent. Examples of carbodiimide compounds include N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N'-diisopropylphenylcarbodiimide, and N-ethyl-N'-(3-dimethylaminopropyl)-carbodiimide hydrochloride. Can be mentioned. The carbodiimide compounds may be used alone or in combination of two or more.

The content of the carbodiimide compound (C) in the surface treatment agent is not particularly limited, but the ratio of the mass (M _c ) of the carbodiimide compound (C) to the mass (M A ) of the aqueous epoxy resin ( _A ) (M _c /M _A ) is preferably blended into the surface treatment agent so that it is 0.020 to 1.100, more preferably blended to the surface treatment agent so that it is 0.040 to 0.700, and 0.080 It is even more preferable to mix it into the surface treatment agent so that the ratio is 0.350 to 0.350.

(Surfactant (D))
The lower the static surface tension value of the surface treatment agent, the better. Specifically, it is preferably 80 dyne/cm or less, more preferably 50 dyne/cm or less, more preferably 40 dyne/cm or less, even more preferably 35 dyne/cm or less, for example. It can be 20 dyne/cm to 35 dyne/cm. In this specification, static surface tension refers to a value measured at a temperature of 25° C. by the Wilhelmy method according to JIS K 2241:2017. In order to reduce the static surface tension value of the surface treatment agent, it is preferable to incorporate a surfactant (D) into the surface treatment agent. Suitable surfactants (D) include fluorine-based surfactants, and in particular, nonionic polyoxyalkylene ether compounds having a perfluoroalkyl group in the side chain can be preferably used. The surfactants may be used alone or in combination of two or more.

The content of the surfactant (D) in the surface treatment agent is not particularly limited, but the solid concentration of the surfactant (D) in the surface treatment agent is 0.005% by mass to 0.250% by mass. It is preferably 0.010% by mass to 0.150% by mass, and even more preferably 0.015% by mass to 0.080% by mass.

(Silane compound (E))
It is preferable to incorporate a silane compound (E) into the surface treatment agent. The type of silane compound (E) is not particularly limited, but one or more types selected from alkoxysilanes, silane coupling agents, and hydrolysates and condensates thereof can be used. For example, epoxysilanes such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-(2-aminoethyl) Aminosilanes such as 3-aminopropylmethyldimethoxysilane, N-(aminoethyl)3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane, mercaptosilanes such as 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyl Examples include isocyanate silanes such as trimethoxysilane and 3-isocyanatepropyltriethoxysilane, and vinyl group-containing silanes such as vinyltriethoxysilane and p-styryltrimethoxysilane. Among these, silane compounds having a methoxy group and/or ethoxy group are preferred, and silane compounds having a methoxy group are more preferred. The silane compounds may be used alone or in combination of two or more.

The content of the silane compound (E) in the surface treatment agent is not particularly limited, but may be determined by the ratio of the mass (M E ) of the silane compound (E) to the mass (M _A ) of the aqueous epoxy resin ( _A ) (M _E /M _A ) is preferably blended into the surface treatment agent so that it is 0.005 to 0.350, more preferably blended into the surface treatment agent so that it is 0.010 to 0.250, and 0.020 It is even more preferable to mix it into the surface treatment agent so that the ratio is 0.150 to 0.150.

(Metal compound (F))
It is preferable to mix at least one metal compound (F) selected from zirconium compounds, titanium compounds, and vanadium compounds in the surface treatment agent. The type of metal compound (F) is not particularly limited as long as it contains at least one of a zirconium atom, a titanium atom, and a vanadium atom. The metal compound (F) may be used alone or in combination of two or more.

Examples of zirconium compounds (compounds containing a zirconium atom) include carbonates, chlorides, nitrates and sulfates of zirconium; ammonium carbonate salts of zirconium such as ammonium zirconium carbonate; zirconic acid and its salts; zirconium oxide; zirconium lactate. and organic acid salts of zirconium such as zirconium acetate: zirconium alkoxides such as zirconium ethoxide, zirconium tetraisopropoxide, diisopropoxyzirconium diacetylacetonate, diisopropoxyzirconium ditriethanolaminate, zirconium hexafluoroacetylacetonate, zirconium Organic zirconium compounds such as tetraacetylacetonate and chelate complexes containing zirconium atoms can be used.

As the titanium compound (compound containing a titanium atom), for example, titanium alkoxide, a chelate complex containing a titanium atom, an inorganic salt of titanium, an organic acid salt, and an organic titanium compound such as titanium acetylacetonate can be used.

As the vanadium compound (compound containing a vanadium atom), for example, vanadium alkoxides, chelate complexes containing vanadium, inorganic salts, organic salts, and oxides of vanadium can be used. Specifically, vanadyl acetylacetonate, metavanadate, sodium metavanadate, potassium metavanadate, ammonium metavanadate, vanadium pentoxide, vanadium trioxide, vanadium fluoride, vanadium phosphate, vanadium sulfate, vanadium oxalate, vanadium oxy. Examples include triisopropoxide, vanadium oxytributoxide, vanadium oxytriisobutoxide, vanadium oxytriethanolaminate, and the like.

The content of the metal compound (F) in the surface treatment agent is not particularly limited, but the ratio of the mass (M F ) of the metal compound (F) to the mass (M _A ) of the aqueous epoxy resin ( _A ) (M _F /M _A ) is preferably blended into the surface treatment agent so that it is 0.001 to 0.050, more preferably blended to the surface treatment agent so that it is 0.002 to 0.035, and 0.003 It is even more preferable to mix it into the surface treatment agent so that the amount of

(Other ingredients)
Surface treatment agents include pigments, water-based lubricants, resin curing components, plasticizers, water-soluble solvents, antifoaming agents, antibacterial and antifungal agents, coloring agents, and other agents such as wettability improvers for uniform coating. These components can be blended within a range that does not impair the liquid stability of the surface treatment agent or the effects of the present invention.

In a preferred embodiment, the surface treatment agent according to the present invention does not contain phosphorus-containing compounds such as inorganic phosphoric acid, inorganic phosphates, organic phosphoric acids, organic phosphates, organic phosphonic acids, and organic phosphonates. The surface treatment agent according to the present invention can form a film with excellent durability on the processed part of the material (corrosion resistance and coating adhesion) without adding a phosphorus-containing compound.

<2. Materials with surface treatment film>
According to one embodiment of the present invention, there is provided a material having a surface treatment film formed by bringing the surface treatment agent according to the present invention into contact with or on the surface of the material. The method for producing a material having a surface treatment film is not particularly limited, but includes, for example, a method in which the above-mentioned surface treatment agent is brought into contact with or on the surface of the material and then heated and dried. As a result, a surface treatment film is formed on or on the surface of the material. One or more other films may be present on the surface of the material, and in this case, the surface of the other film is brought into contact with the above-mentioned surface treatment agent and dried by heating. As a result, a surface treatment film is formed on the surface of another film, in other words, on the surface of the material. Other films may be formed by any method, for example, by surface treatment described below. Hereinafter, a method for manufacturing a material having a surface treatment film will be described in detail.

(material)
There are no particular limitations on the materials to which the surface treatment agent according to the present invention is applied, but examples thereof include metal materials in general (metal materials). The type of metal material used is not particularly limited, and any known metal material can be used. Examples include iron-based materials, plating-based materials, zinc-based materials, aluminum-based materials, magnesium-based materials, and the like. More specifically, iron plates, zinc plates, cold-rolled steel plates, hot-rolled steel plates, hot-dip galvanized steel plates, electrogalvanized steel plates, molten alloyed galvanized steel plates, aluminum-plated steel plates, aluminum-zinc alloy plated steel plates, and tin-zinc alloy plates. Examples include alloy plated steel plates, zinc-nickel alloy plated steel plates, stainless steel plates, aluminum plates (including not only single aluminum plates but also aluminum alloy plates), copper plates, titanium plates, magnesium plates, etc. The shape of the metal material may be a shape such as a metal sheet metal structure.

(pre-cleaning)
Prior to treatment with a surface treatment agent, alkaline cleaning with a degreasing agent, hot water cleaning, pickling, solvent cleaning, etc. are appropriately combined to remove oil and dirt adhering to the material to be treated, although this is not essential. It is preferable to do so. After pre-cleaning, it is preferable to wash with water and dry so that no cleaning liquid remains on the surface of the material.

(surface treatment)
Although normally unnecessary, a surface treatment may be performed before the treatment with a surface treatment agent for the purpose of further improving the corrosion resistance of the material and the adhesion between the film and the metal material. The method of surface treatment is not particularly limited, but may include surface conditioning treatment to adhere metals such as Fe, Co, Ni, Cu, Zn, Mn, Zr, Ti, or V, and chemical conversion treatments such as phosphate-based and zirconium-based treatments. Examples include. After the surface treatment, the material may be washed with water and dried so that no treatment liquid remains on the surface of the material, or may not be washed with water.

(Surface treatment using surface treatment agent)
The method of contacting the surface treatment agent with the material is not particularly limited, and examples thereof include coating methods such as a roll coater method, a dipping method, a spray method, and a bar coating method. The temperature of the surface treatment agent during contact is not particularly limited, but is preferably 10°C to 60°C, more preferably 15°C to 40°C. After bringing the material into contact with the surface treatment agent, the material is subjected to a heat drying treatment. There are no particular limitations on the heating and drying method, and examples include a dryer, a hot air oven, a high frequency induction heating oven, an infrared oven, and the like. In order to enhance the coating effect by promoting curing and crosslinking of the aqueous epoxy resin (A) and block isocyanate (B), heating and drying using a hot air oven, induction heating furnace, electric furnace, etc. is preferable. The heat drying temperature is not particularly limited, but the peak metal temperature (PMT) during drying is preferably 50°C to 250°C, more preferably 70°C to 220°C.

The thickness of the surface treatment film formed by the above procedure is not particularly limited, but the average thickness is preferably 0.1 μm to 5.0 μm, more preferably 0.5 μm to 4.0 μm.

EXAMPLES Below, the content of the present invention will be specifically explained with reference to Examples and Comparative Examples. This example is only a part of explaining the present invention, and does not limit the present invention.

First, the water-based epoxy resin (A) used in Examples and Comparative Examples will be explained.
(1) Water-based epoxy resin (A1) to (A4)

Synthesis of aqueous epoxy resin (A1) 114 parts by mass of 2,2-bis(4-hydroxyphenyl)propane, 56 parts by mass of epichlorohydrin, and 17 parts by mass of tetrabutylammonium bromide were added to a flask equipped with a cooling tube. , and reacted at 70°C for 24 hours. Next, the reaction solution was cooled to room temperature, 12 parts by mass of a 20% by mass aqueous sodium hydroxide solution was added to the reaction solution, and the mixture was allowed to react at room temperature for about 5 hours, followed by extraction with chloroform to obtain a reaction product.
To 590 parts by mass of this reaction product, 43 parts by mass of glycidyl methacrylate and 7 parts by mass of dimethylbenzylamine were added, and the mixture was reacted at 130° C. for 4 hours to obtain a reaction product (a1).
To 265 parts by mass of this reaction product (a1), 150 parts by mass of butyl cellosolve was added, 30 parts by mass of a mixture of methyl methacrylate/2-hydroxyethyl methacrylate/acrylic acid = 375/210/173, and 30 parts by mass of butyl cellosolve. A mixture consisting of parts by mass and 10 parts by mass of t-butylperoxy-2-ethylhexanoate was added dropwise over 2 hours, and the mixture was reacted at 100° C. for 4 hours. Thereafter, the reaction vessel was cooled to 80° C., and 10 parts by mass of triethylamine and 500 parts by mass of deionized water were sequentially added to the reaction vessel and mixed to obtain an aqueous epoxy resin (A1). The acid value of this aqueous epoxy resin (A1) was 17 mgKOH/g.

Synthesis of aqueous epoxy resin (A2) 100 parts by mass of 2,2-bis(4-hydroxyphenyl)methane, 56 parts by mass of epichlorohydrin, and 17 parts by mass of tetrabutylammonium bromide were added to a flask equipped with a cooling tube. , and reacted at 70°C for 24 hours. Next, the reaction solution was cooled to room temperature, 12 parts by mass of a 20% by mass aqueous sodium hydroxide solution was added to the reaction solution, and the mixture was allowed to react at room temperature for about 5 hours, followed by extraction with chloroform to obtain a reaction product.
To 534 parts by mass of this reaction product, 60 parts by mass of polyethylene glycol diglycidyl ether (manufactured by Nagase Chemtech, EX-821) and 7 parts by mass of dimethylbenzylamine were added, and the mixture was reacted at 130°C for 4 hours to form a reaction product. Product (a2) was obtained.
To 254 parts by mass of this reaction product (a2), 150 parts by mass of butyl cellosolve was added, 35 parts by mass of a mixture of methyl methacrylate/2-hydroxyethyl methacrylate/acrylic acid = 375/210/288 mass ratio, and 30 parts by mass of butyl cellosolve. and 10 parts by mass of t-butylperoxy-2-ethylhexanoate was added dropwise over 2 hours, and the mixture was reacted at 100° C. for 4 hours. Thereafter, the reaction vessel was cooled to 80° C., and 16 parts by mass of triethylamine and 500 parts by mass of deionized water were sequentially added to the reaction vessel and mixed to obtain a water-based epoxy resin (A2). The acid value of this aqueous epoxy resin (A2) was 28 mgKOH/g.

Synthesis of aqueous epoxy resin (A3) 114 parts by mass of 2,2-bis(4-hydroxyphenyl)propane, 56 parts by mass of epichlorohydrin, and 17 parts by mass of tetrabutylammonium bromide were added to a flask equipped with a cooling tube. , and reacted at 70°C for 24 hours. Next, the reaction solution was cooled to room temperature, 12 parts by mass of a 20% by mass aqueous sodium hydroxide solution was added to the reaction solution, and the mixture was allowed to react at room temperature for about 5 hours, followed by extraction with chloroform to obtain a reaction product.
To 590 parts by mass of this reaction product, 43 parts by mass of glycidyl methacrylate and 7 parts by mass of dimethylbenzylamine were added and reacted at 130° C. for 4 hours to obtain a reaction product (a3).
150 parts by mass of butyl cellosolve was added to 254 parts by mass of this reaction product (a3), 40 parts by mass of a mixture with a mass ratio of methyl methacrylate/2-hydroxyethyl methacrylate/acrylic acid = 375/210/405, and 30 parts by mass of butyl cellosolve. and 10 parts by mass of t-butylperoxy-2-ethylhexanoate was added dropwise over 2 hours, and the mixture was reacted at 100° C. for 4 hours. Thereafter, the reaction vessel was cooled to 80° C., and 22 parts by mass of triethylamine and 500 parts by mass of deionized water were sequentially added to the reaction vessel and mixed to obtain an aqueous epoxy resin (A3). The acid value of this aqueous epoxy resin (A3) was 40 mgKOH/g.

(Property measurement of water-based epoxy resin: acid value)
The acid value of the aqueous epoxy resin produced in the above synthesis example was measured by potentiometric titration according to JIS K0070-1992.

Water-based epoxy resin (A4)
As the aqueous epoxy resin (A4), an epoxy resin having a hydroxyl group (Watersol EFD-5560, manufactured by DIC Corporation) was used.

Next, the blocked isocyanate (B) used in Examples and Comparative Examples will be explained.
(2) Synthesis of blocked isocyanate (B) Preparation of polyisocyanate 300 g of each isocyanate shown in the "Isocyanate species" column of Table 1 was added to a reaction apparatus equipped with a stirrer (1 L separable flask), and the mixture was stirred at 60°C. , 0.1 g of trimethylbenzylammonium hydroxide was added as a catalyst. After 4 hours, when the conversion rate of the reaction solution reached 38%, an organic acid was added to stop the reaction.

Preparation of Blocked Isocyanate The method for preparing blocked isocyanate will be described below. The "polyisocyanate" used in each synthesis example was prepared using the isocyanate listed in the "Isocyanate species" column of each synthesis example in Table 1 using the above procedure.
The block isocyanate synthesized in each synthesis example below was a so-called self-emulsifying block isocyanate.

(Synthesis examples B1, B4)
Polyisocyanate (100 g), 3,5-dimethylpyrazole (28.8 g) and sodium methoxide (1.0 g) were charged into a reactor and heated at 65-70°C. Next, polyethylene glycol (188.4 g) was added to the reaction solution, and the reaction solution temperature was brought to 70° C. and maintained for 5 hours. Thereafter, water (430 g) was added to the reaction solution while stirring it to prepare a blocked isocyanate emulsion.
In the production of B1 and B4, the type of polyethylene glycol was changed so that the weight average molecular weight shown in Table 1 could be obtained. Specifically, polyethylene glycol (number of repeating units (n): 22) was used in the synthesis of B1, and polyethylene glycol (number of repeating units (n): 180) was used in the synthesis of B4. .

(Synthesis example B2)
A blocked isocyanate emulsion was prepared in the same manner as in Synthesis Example B1, except that polyethylene glycol was changed to polypropylene glycol (number of repeating units (n): 17).

(Synthesis example B3)
Polyisocyanate (100 g), 3,5-dimethylpyrazole (26.2 g) and sodium methoxide (1.0 g) were charged into a reactor and heated at 65-70°C. Next, polyethylene glycol (136.6 g) (number of repeating units (n): 68) was added to the reaction solution, and the reaction solution temperature was brought to 70° C. and maintained for 5 hours. Thereafter, water (350 g) was added to the reaction solution while stirring it to prepare a blocked isocyanate emulsion.

(Synthesis example B5)
A blocked isocyanate emulsion was prepared in the same manner as in Synthesis Example B1 except that 3,5-dimethylpyrazole was changed to ethylene glycol monobutyl ether.

(Synthesis example B6)
Polyisocyanate (100 g), 3,5-dimethylpyrazole (75.7 g) and sodium methoxide (1.0 g) were charged into a reactor, and the reaction solution was heated at 65-70°C. Thereafter, water (260 g) was added to the reaction solution while stirring it to prepare a blocked isocyanate emulsion.

The weight average molecular weight of the obtained blocked isocyanate was determined by determining the relative molecular weight distribution of the block isocyanate by GPC (gel permeation chromatography) and determining the weight average molecular weight in terms of polyethylene glycol. The measurement conditions for GPC are as follows.

Measurement model: Tosoh Corporation SC-8010 System Column: Shodex Ohpak SB-G + Ohpak SB-806MHQ x 2 Dissolution solution: DMF/0.06M LiBr/0.04M H ₃ PO ₃
Temperature: Column constant temperature bath 40℃
Flow rate: 0.05mL/min Concentration: 0.1wt/Vol%
Injection volume: 50μL
Solubility: Complete dissolution Pretreatment: 0.45 μm filter Detector: Differential refractometer

B1 to B5 synthesized above contained an isocyanurate structure and a polyalkyleneoxy chain.
Although B6 contained an isocyanurate structure, it did not contain a polyalkyleneoxy chain.
In Table 1 below, in the "polymerization form" column, "trimer" indicates that an isocyanurate structure is included.
"Alkyleneoxy number" represents the number of alkyleneoxy units.
"Particle diameter" represents the volume-based median diameter of the block isocyanate in each block isocyanate emulsion as measured using a particle size distribution analyzer (Model LA-960, manufactured by HORIBA) using a laser diffraction/scattering method.
"Effective NCO%" represents the content (mass%) of effective isocyanate groups in each block isocyanate, measured according to the method specified in JIS K1603-1:2007.

In addition, each symbol in the above table represents the following.
HDI: 1,6-hexamethylene diisocyanate, TMXDI: 1,3-bis(2-isocyanate 2-propyl)benzene, TDI: tolylene-2,6-diisocyanate, PEG: polyethylene glycol, PPG: polypropylene glycol, DMP: 3 , 5-dimethylpyrazole, EGB: ethylene glycol monobutyl ether

(3) Preparation of surface treatment agent Next, using the above-mentioned aqueous epoxy resins (A1) to (A4) and block isocyanates (B1) to (B6) shown in Table 1, prepare the composition shown in Table 2 ( Each component of A) to (F) was mixed in deionized water to obtain a surface treatment agent for metal materials. In addition, the solid content concentration of all the surface treatment agents for metal materials was 10% by mass.

In Table 2, "M _B /M _A " is the ratio of the mass of blocked isocyanate (B) to the mass of the water-based epoxy resin (A), and "M _C /M _A " is the ratio of the mass of the block isocyanate (B) to the mass of the water-based epoxy resin (A). "(D) content (%)" is the mass ratio of the compound (C), "(D) content (%)" is the mass % of the solid content of the surfactant (D) in the surface treatment agent, and "M _E /M _A " is the aqueous epoxy "M F /M A " represents the ratio of the mass of the silane compound (E) to the mass of the resin (A), and "M _F /M _A " represents the ratio of the mass of the metal compound (F) to the mass of the aqueous epoxy resin (A), respectively.

Compounds (C), (D), (E), and (F) listed in Table 2 will be explained below.
C1: N,N'-dicyclohexylcarbodiimide

D1: Nonionic polyoxyalkylene ether compound having a perfluoroalkyl group in the side chain (PolyFox PF-151N manufactured by Omnova)

E1: 3-glycidoxypropyltrimethoxysilane E2: 3-aminopropyltriethoxysilane E3: Vinyltriethoxysilane

F1: Zirconium ammonium carbonate F2: Titanium acetylacetonate F3: Vanadyl acetylacetonate F4: Zirconium hexafluoroacetylacetonate

Although not listed in Table 2, in Comparative Example 4 corresponding to the invention of Patent Document 1, the ratio of the mass of citric acid monohydrate to the mass of the aqueous epoxy resin (A) (citric acid monohydrate Citric acid monohydrate was further added so that the ratio (mass of /mass of aqueous epoxy resin (A)) was 0.12, and in Comparative Example 7, which corresponds to Example C13 of Patent Document 2, the mass of the phosphorus-containing compound Ammonium phosphate was further added as a phosphorus-containing compound so that the ratio of the mass of the block isocyanate (B) to the total weight of the block isocyanate (B) (mass of the block isocyanate (B)/mass of the phosphorus-containing compound) was 0.1.

(4) Static surface tension measurement of surface treatment agent The surface treatment agent for metal materials prepared by the above procedure was measured using a high-performance surface tension meter (Kyowa Interface Science "DY-500"), and measured according to JIS K 2241:2017. Static surface tension was measured at a temperature of 25° C. using the Wilhelmy method according to . The results are shown in Table 2.

(5) Preparation of a test plate with a surface-treated film A test plate with a surface-treated film was prepared according to the steps (5-1) to (5-3), and the film was coated according to the steps (5-4). The thickness was measured.
(5-1) Test material A cold rolled steel plate (SPCC) with a thickness of 0.8 mm was used as the test plate.

(5-2) Pre-cleaning In advance, the test plate was cleaned with an alkaline degreaser (alkaline degreaser Fine Cleaner L4460 manufactured by Nippon Parkerizing Co., Ltd., degreasing conditions: degreaser concentration in water 2.0 g/L, treatment liquid temperature 45°C, degreasing time A degreasing treatment was performed using a sprayer for 120 seconds to remove oil and dirt from the surface. Next, after washing with tap water and confirming that the surface of the test plate was 100% wet with water, deionized water was further poured over the test plate, and moisture was dried in an oven at 100°C.

(5-3) Preparation of test plate with surface treatment film After pre-cleaning, a surface treatment agent for metal materials having the composition shown in Table 2 was applied to one surface of the test plate using a bar coater, and then heated in a hot air drying oven. The sample was dried so that the peak metal temperature (PMT) reached the temperature shown in Table 2 to obtain a test plate having a surface treated film.

(5-4) Measuring the film thickness of the film The film thickness of the test plate with the surface treatment film was measured using a dual type film thickness meter LZ-373 (manufactured by Kett Science Institute) on the surface of a 70 mm x 150 mm steel plate. Measurements were taken at five locations within the range, and the average value was calculated. The results are shown in Table 2.

(6) Evaluation test method Table 3 shows the results of the following evaluations (6-1) to (6-3) performed on the test plate having the surface treated film obtained by the above procedure. Regarding the evaluation criteria, "◎", "○+", and "○" are practically preferable.

(6-1) Wet test initial rust prevention evaluation A 70 mm x 150 mm test piece (hereinafter simply referred to as a "sample") was cut out from a test plate with a surface treatment film. After sealing the other surface (not the other surface) and end surface with vinyl tape, a humidity test (49°C, 95% RH) in accordance with JIS K 2246:2018 was conducted, and the time until red rust appeared on the sample surface was visually determined. . Evaluation was made based on the following evaluation criteria. The results are shown in the "Wetting test" column of Table 3.
◎: 720 hours or more 〇+: 600 hours or more and less than 720 hours ○: 480 hours or more and less than 600 hours △: 240 hours or more and less than 480 hours ×: less than 240 hours

(6-2) SST Initial Rust Prevention Evaluation Flat Section The back and end surfaces of each sample were sealed with vinyl tape, and a salt spray test (SST) in accordance with JIS Z 2371:2000 was conducted. The area ratio of red rust occurrence after 36 hours was visually confirmed, and the corrosion resistance on the sample surface (flat portion) was evaluated based on the following evaluation criteria. The results are shown in the "Plane part SST" column of Table 3.
◎: Red rust area ratio less than 5%〇+: Red rust area ratio 5% or more and less than 10% 〇: Red rust area ratio 10% or more and less than 20% △: Red rust area ratio 20% or more and less than 30%
×: Processed area with red rust area ratio of 30% or more The back and end faces of each sample were sealed with vinyl tape, and extrusion processing was performed using an Erichsen tester so that a convex portion with a height of 5 mm was formed on the sample surface. Next, a salt spray test (SST) in accordance with JIS Z 2371:2000 was conducted. The area ratio of red rust occurrence after 24 hours was visually confirmed, and the corrosion resistance of the convex portions (processed portions) on the sample surface was evaluated. Evaluation was made based on the following evaluation criteria. The results are shown in the "Processed part SST" column of Table 3.
◎: Red rust area ratio less than 5%〇+: Red rust area ratio 5% or more and less than 10% 〇: Red rust area ratio 10% or more and less than 20% △: Red rust area ratio 20% or more and less than 30%
×: Red rust area ratio 30% or more

(6-3) Paint film adhesion evaluation A melamine paint (Amilac #1000, manufactured by Kansai Paint Co., Ltd.) was applied to the surface of each sample so that the film thickness after baking and drying was 25 μm. A top coat was applied by baking for 20 minutes.

Primary adhesion Use a cutter to draw 11 parallel lines at 1 mm intervals on the surface of each sample after topcoating, and then draw 11 parallel lines at 1 mm intervals perpendicular to these parallel lines to form 100 grid patterns. I made a cut. Next, extrusion processing was performed using an Erichsen tester so that convex portions with a height of 5 mm were formed on the sample surface, cellophane tape was applied to the grid areas, and after peeling off the tape, the number of peeled pieces in the grid pattern of the coating film was determined as follows. Evaluation was made according to the criteria. (Hereinafter referred to as the "checkerboard test.") The results are shown in the "Primary" column of "Coating Performance" in Table 3.
◎: 0 pieces〇+: 1 to 5 pieces 〇: 6 to 10 pieces △: 11 to 30 pieces ×: 31 or more pieces Secondary adhesion After each sample after top coating was immersed in boiling deionized water for 2 hours. , leave it for one day, use a cutter to draw 11 parallel lines at 1 mm intervals on the surface of each sample, and then draw 11 parallel lines at 1 mm intervals perpendicular to these parallel lines to form 100 pieces in a grid pattern. I made a cut. Next, extrusion processing was performed using an Erichsen testing machine so that a convex portion with a height of 5 mm was formed on the sample surface, and evaluation was performed using a grid test. The results are shown in the "Secondary" column of "Coating Performance" in Table 3.
◎: 0 pieces〇+: 1 to 5 pieces 〇: 6 to 10 pieces △: 11 to 30 pieces ×: 31 pieces or more

Note that even when test materials other than those used in this study were used, materials with surface treatment films showing the same evaluation trends as in the above examples and having excellent properties were obtained.

Claims (4)

A surface treatment agent containing an aqueous epoxy resin (A), a blocked isocyanate (B), a carbodiimide compound (C), and water,
The aqueous epoxy resin (A) has a structure in which one or more types of vinyl monomers are polymerized, and the one or more types of vinyl monomers include a vinyl monomer having a carboxyl group,
The blocked isocyanate (B) has an isocyanate group blocked by a blocking agent, an isocyanurate structure, and a polyalkyleneoxy chain.
Surface treatment agent. Mass (M) of the aqueous epoxy resin (A) _A ) of the carbodiimide compound (C) (M _c ) ratio (M _c /M _A ) is 0.040 to 0.700, the surface treatment agent according to claim 1. The surface treatment agent according to claim 1 or 2, which has a static surface tension value of 35 dyne/cm or less. A material having a surface treatment film formed by bringing the surface treatment agent according to any one of claims 1 to 3 into contact with or on the surface of the material.