JP7094973B2 - A method for manufacturing a water-based rust-preventive paint composition, a rust-preventive coating film, a base material with a rust-preventive coating film, and a base material with a rust-preventive coating film. - Google Patents

Description

The present invention relates to a water-based rust-preventive coating composition, a rust-preventive coating, a base material with a rust-preventive coating, and a method for producing a base material with a rust-preventive coating.

Various industrial fields, such as (land) structures such as bridges, tanks, plants and (transport) containers, are usually coated with a rust preventive coating to prevent corrosion. As a composition for forming this rust-preventive coating film, it has been desired in recent years to switch from a solvent paint to a water-based paint (water-based rust-preventive paint composition) from the viewpoint of environmental protection and safety of the working environment.

As the water-based rust-preventive coating composition, coating compositions such as an alkyd resin-based, an epoxy ester resin-based, and an epoxy-amine curing system in which an epoxy resin and an amine-based curing agent are reacted are known.
Further, Patent Document 1 uses an aqueous resin dispersion obtained by emulsion polymerization of a monomer mixture containing a fatty acid-modified unsaturated monomer and another polymerizable unsaturated monomer copolymerizable with the monomer, thereby providing corrosion resistance and water resistance. It is disclosed that it is possible to form an excellent coating film. Patent Document 2 describes a composition in which a modified epoxy ester obtained by reacting an epoxy resin with an unsaturated fatty acid and further reacting with an ethylenically unsaturated monomer containing an unsaturated carboxylic acid, and a (semi) dry oil are combined. It is disclosed that a coating film having excellent corrosion resistance and water resistance can be formed by using a substance.

International Publication No. 2004/074327 Japanese Patent Application Laid-Open No. 2003-64302

Since the conventional water-based rust-preventive paint composition such as the alkyd resin-based and the epoxy ester resin-based and the coating film formed from the compositions described in Patent Documents 1 and 2 are cured by the oxidative polymerization reaction, they are cured. It took time to exhibit sufficient coating performance. In addition, when an undercoat coating film is formed from these compositions and a topcoat coating film is applied over the topcoat coating film to form a topcoat coating film, lifting may occur unless the topcoat coatings are applied at appropriate intervals. .. Further, the coating film formed from these compositions needs to be further improved in a usage environment where mechanical properties such as high corrosion resistance, water resistance and impact resistance are required.
Further, the coating film formed from the epoxy-amine curing water-based rust-preventive coating composition has a high shrinkage stress due to a cross-linking reaction, has excellent corrosion resistance and water resistance to a substrate, and has excellent water resistance. It was difficult to obtain a coating film having sufficient adhesiveness.

Non-ferrous metals and stainless steel are used as the material of the structure, particularly the transport container such as a freezing / refrigerating container. Since the surface of these materials has an oxide film formed, the surface activity is low, and it is difficult to firmly adhere the rust preventive coating film formed by using the conventional water-based rust preventive paint composition to these surfaces. It turned out to be.
Impact resistance is also required for the rust-preventive coating film formed on the structure, particularly the transport container.

One embodiment of the present invention is a water-based rust-preventive paint composition that can be cured at room temperature (5 to 35 ° C.) and has excellent drying properties, has excellent corrosion resistance and water resistance, and is a base material, particularly a non-ferrous metal. Provided is a water-based rust-preventive coating composition capable of forming a coating film having excellent adhesion and impact resistance even on a base material or a stainless steel base material.

As a result of diligent studies on a method for solving the above-mentioned problems, it was found that the above-mentioned problems can be solved by a coating composition having a specific composition, and the present invention has been completed.
The configuration example of the present invention is as follows.

<1> A water-based rust-preventive coating composition containing a water-based resin (A) having one or more carboxy groups in one molecule and a water-based epoxy resin (B) other than the water-based resin (A).

<2> The water-based resin (A) according to <1>, wherein the aqueous resin (A) contains at least one selected from an aqueous alkyd-modified acrylic resin (A1) having a carboxy group and an aqueous modified epoxy resin (A2) having a carboxy group. Aqueous rust preventive paint composition.
<3> The water-based rust-preventive paint composition according to <2>, wherein the alkyd-modified acrylic resin (A1) and the modified epoxy resin (A2) are resins having a bisphenol A structure.

<4> In any of <1> to <3>, the aqueous epoxy resin (B) is contained in an amount of 1 to 30 parts by mass as a non-volatile content with respect to 100 parts by mass of the non-volatile content of the aqueous resin (A). The water-based rust preventive paint composition according to the above.

<5> Any of <1> to <4>, which is a multi-component type containing the first agent containing the aqueous resin (A) and the second agent containing the aqueous epoxy resin (B). The water-based rust preventive paint composition according to the above.

<6> The water-based rust preventive paint composition according to any one of <1> to <5>, which further contains a pigment (D).
<7> The water-based rust preventive paint composition according to <6>, wherein the pigment (D) contains a rust preventive pigment (D1).
<8> The water-based rust-preventive paint composition according to <6> or <7>, wherein the pigment volume concentration (PVC) in the water-based rust-preventive paint composition is 20 to 50%.

<9> A rust-preventive coating film formed from the water-based rust-preventive paint composition according to any one of <1> to <8>.
<10> A base material with a rust-preventive coating film having the rust-preventive coating film and the base material according to <9>.
<11> The base material with a rust-preventive coating film according to <10>, wherein the base material is a non-ferrous metal or stainless steel.

<12> A method for producing a base material with a rust-preventive coating film, which comprises the following steps [1] and [2].
[1] Step of applying the water-based rust-preventive paint composition according to any one of <1> to <8> to the base material [2] Dry the water-based rust-preventive paint composition coated on the base material. Step to form rust preventive coating

According to one embodiment of the present invention, it is a water-based rust-preventive paint composition that can be cured at room temperature and has excellent dryness, has excellent corrosion resistance and water resistance, and is particularly not only a base material made of steel or the like. It is possible to provide a water-based rust-preventive coating composition capable of forming a coating film having excellent adhesion and impact resistance even on a non-ferrous metal base material or a stainless steel base material.
Further, the water-based rust-preventive coating composition according to the embodiment of the present invention is also excellent in adhesion to the topcoat coating film formed on the rust-preventive coating film obtained from the composition, and in particular, the rust-preventive coating film is excellent. Regardless of the interval from the formation of the coating film to the formation of the topcoat coating film, coating film defects such as lifting are unlikely to occur, so that a desired laminated coating film can be easily formed.

Hereinafter, the water-based rust-preventive paint composition, the rust-preventive coating film, the base material with the rust-preventive coating film, and the method for producing the same will be described. However, the present invention is not limited by the following description.

≪Aqueous rust preventive paint composition≫
The water-based rust-preventive coating composition according to one embodiment of the present invention (hereinafter, also simply referred to as “the present composition”) is a water-based resin (A) having one or more carboxy groups in one molecule (hereinafter, “components (hereinafter” components (”). A) ”. The same applies to other components), and the composition contains an aqueous epoxy resin (B) other than the aqueous resin (A).
This composition is a water-based rust-preventive coating composition that can be cured at room temperature and has excellent drying properties, and according to the composition, it has excellent corrosion resistance and water resistance, and is a base material, particularly a non-ferrous metal base material. It is possible to form a coating film having excellent adhesion and impact resistance even on a stainless steel substrate.

In particular, this composition is also excellent for substrates such as non-ferrous metal substrates and stainless steel substrates, for which it was difficult to form a coating film having sufficient adhesiveness with conventional compositions. A coating film having adhesiveness and impact resistance can be formed. The detailed mechanism of action by which this composition exerts the above effects is not always clear, but the following can be considered as an example.
In this composition, the carboxy group of the component (A) and the epoxy group of the component (B) undergo a cross-linking reaction to form a hydroxyl group and an ester bond, and can be firmly bonded to the surface of the substrate. As a result, as compared with conventional compositions such as alkyd resin type, epoxy ester resin type and epoxy-amine curing type, the coating film has excellent adhesion to the substrate and also has excellent impact resistance due to the cross-linking reaction. Can be formed.

This composition is suitable for the outer surface of a freezing / refrigerating container in which materials such as non-ferrous metals (eg, aluminum, copper, brass, zinc plating, zinc spraying) and stainless steel (eg, SUS304, SUS410) are often used. Therefore, it is suitably used as a paint capable of forming a rust-preventive coating film having excellent adhesion and impact resistance to the substrate.

In the present invention, the "water-based rust-preventive paint composition" refers to water or a medium containing water as a main component (water-based medium) in which components (A) and components (B) are dispersed and / or dissolved. It refers to the rust-preventive paint composition that has been made.

Further, in the present invention, the "aqueous resin" is water or a resin using water as a main solvent or a dispersion medium, or a resin that can be mixed with water (dilutable with water), and more specifically, Examples thereof include water-dispersible resins, water-soluble resins and self-emulsifying resins. The resin that can be mixed with water (dilutable with water) means a resin that does not show a significant increase in viscosity when mixed with water.

Such an aqueous resin can be obtained by a conventionally known method, for example, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, a seed polymerization method, a miniemulsion polymerization method, a microemulsion polymerization method, or an emulsifier-free (soap-free) emulsification polymerization method. It can be synthesized by such as. In addition to these, an aqueous resin can also be obtained by a known method, for example, a method of emulsifying by phase inversion emulsification, D-phase emulsification, forced emulsification, gel emulsification, reversal emulsification, high-pressure emulsification or the like.

Since this composition uses the water-based resin (A) and the water-based epoxy resin (B), it is a coating composition having excellent ease of preparation, storage stability, and the like.
It should be noted that it tends to be difficult to prepare a desired coating composition by mixing water with a resin having a carboxy group and an epoxy resin, which are not the "water-based resin". Therefore, it is preferable to use water-containing components as the components (A) and (B), respectively.

The form of the present composition is preferably a multi-component type composition containing the first agent and the second agent in consideration of storage stability and easiness of storage, and for example, the first component (A) is contained. A first agent containing one agent, preferably the component (A) and water (C), more preferably a first agent containing the component (A), water (C) and a pigment (D), and the above. A two-component composition containing a second agent containing the component (B), preferably a second agent containing the component (B) and water (C) is desirable. Further, it is also possible to prepare a composition of a three-component type or more containing a third agent or the like containing the following other components and the like.

Further, when the present composition is a multi-component type composition containing the first agent and the second agent, a method for forming a coating film by adjusting the amounts of the component (A) and the component (B) used. , The crosslink density of the formed coating film can be easily adjusted according to the type of the base material, the application, the coating environment and the like. As a result, it is possible to easily adjust the balance between the toughness and the flexibility of the coating film according to the required performance.
Further, when the present composition is a multi-component type composition containing the first agent containing the component (A) and the component (D) and the second agent containing the component (B), carboxy Since the component (A) having a group has an affinity for the component (D), it is expected that the dispersibility of the component (D) will be improved. As a result, improvement in production efficiency due to improvement in the dispersibility of the component (D) can be expected.

<Aqueous resin (A) having a carboxy group>
The component (A) is not particularly limited as long as it is an aqueous resin having one or more carboxy groups in one molecule.
The component (A) contained in the present composition may be one kind or two or more kinds.

The content of the non-volatile component (A) with respect to 100% by mass of the non-ferrous content of the present composition is well-balanced due to corrosion resistance, water resistance, adhesion to a base material, particularly a non-ferrous metal base material or a stainless steel base material, and impact resistance. It is preferably 20 to 50% by mass, more preferably 25 to 45% by mass, from the viewpoint that an excellent coating film can be easily formed.

Examples of the resin contained in the component (A) include acrylic resin, alkyd resin, epoxy resin, urethane resin, polyester resin, vinyl acetate resin, phenoxy resin, and modified products thereof having a carboxy group. Examples of the modified product include an acrylic modified product, an alkyd modified product, an epoxy modified product, an amine modified product and a urethane modified product, and examples thereof include an alkyd modified acrylic resin, an acrylic modified alkyd resin, an acrylic modified epoxy resin and an amine modified product. Examples thereof include modified epoxy resins such as epoxy resins and acrylic modified urethane resins. Here, the alkyd-modified acrylic resin refers to a resin in which the ratio of the structural units constituting the acrylic resin exceeds 50% by mass with respect to 100% by mass of all the structural units constituting the resin. That is, the modified product refers to a resin in which the proportion of structural units derived from the modified component is less than 50% by mass.
Among these, a resin having no epoxy group is preferable from the viewpoint of obtaining a composition having better storage stability, and corrosion resistance, water resistance, and adhesion to a base material, particularly a non-ferrous metal base material or a stainless steel base material. One or more of the alkyd-modified acrylic resin (A1) having a carboxy group and the modified epoxy resin (A2) having a carboxy group, which will be described later, from the viewpoint of easily forming a well-balanced coating film due to impact resistance. Is preferable.

The content of the resin in 100% by mass of the component (A) is preferably 30 to 75% by mass, more preferably 30 to 75% by mass, from the viewpoint of obtaining a coating composition excellent in ease of preparation, storage stability and the like. It is 35 to 60% by mass.
The residue of the component (A) preferably contains water, and if necessary, a conventionally known component such as a surfactant may be contained.

<Alkyd-modified acrylic resin (A1) having a carboxy group>
The alkyd-modified acrylic resin (A1) having a carboxy group can be synthesized, for example, by using a (meth) acrylic compound and an alkyd resin, and an unsaturated monomer containing a (meth) acrylic compound, an alkyd resin, and an epoxy compound. It is more preferable that the resin is synthesized using and.
Specifically, a solvent is added to the alkyd resin, an epoxy compound and a catalyst such as triphenylphosphine are added thereto, and the mixture is reacted at 70 to 170 ° C. for about 3 to 15 hours, and then the (meth) acrylic compound is not contained. It can be synthesized by adding a predetermined amount of a saturated monomer and a polymerization initiator and reacting at 80 to 150 ° C. for about 3 to 10 hours.

In order to obtain the resin (A1) having a carboxy group, for example, a compound having a carboxy group may be used as the unsaturated monomer, a compound having a carboxy group may be used as the alkyd resin, and the epoxy compound may be carboxy. A compound having a group may be used, a carboxy group may be generated when these are reacted, and after the reaction, modification or the like is performed so that the finally obtained resin has a carboxy group. You may go.

The alkyd resin can be obtained by a conventionally known method, but contains (semi) drying oil, (semi) drying oil fatty acid or unsaturated fatty acid excluding the unsaturated monomer, an acid component, and a polyhydric alcohol component. It is preferably a resin obtained by polycondensation, and an epoxy compound may be used if necessary.

Examples of the (semi) dry oil include fish oil, dehydrated castor oil, safflower oil, flaxseed oil, soybean oil, sesame oil, poppy oil, eno oil, hemp seed oil, grape kernel oil, corn oil, tall oil, and sunflower oil. , Cotton seed oil, walnut oil, rubber seed oil, and examples of the (semi) dry oil fatty acid include fish oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, flaxseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, and poppy oil. Examples thereof include fatty acids, eno oil fatty acids, hemp oil fatty acids, grape kernel oil fatty acids, corn oil fatty acids, tall oil fatty acids, sunflower oil fatty acids, cottonseed oil fatty acids, walnut oil fatty acids, and rubber seed oil fatty acids. Examples of the fatty acid include palmitoleic acid, oleic acid, baxenoic acid, linoleic acid, linolenic acid, stearidonic acid, and eicosapentaenoic acid. These can be used alone or in combination of two or more.

The amount of the (semi) drying oil, the (semi) drying oil fatty acid and the unsaturated fatty acid excluding the unsaturated monomer is preferably 20 to 70% by mass with respect to 100% by mass of the monomer component in synthesizing the alkyd resin. %, More preferably 30 to 60% by mass.

Examples of the acid component include acids other than the compounds exemplified as the (semi) dry oil, the (semi) dry oil fatty acid and the unsaturated fatty acid excluding the unsaturated monomer, and specific examples thereof include phthalic acid. , Isophthalic acid, terephthalic acid, maleic acid, oxalic acid, malonic acid, glutaric acid, fumaric acid, itaconic acid, succinic acid, adipic acid, trimellitic acid, hemmellitic acid, trimesic acid, merophanic acid, planar acid, pyromerit Acid, merit acid, difenic acid, hydride trimellitic acid, hydride pyromellitic acid, benzoic acid, rosin, crotonic acid, capric acid, lauric acid, myristic acid, pentadecic acid, palmitic acid, margaric acid, stearic acid, arachidin Acid is mentioned. These can be used alone or in combination of two or more.
Among these, it is preferable to use a polyfunctional carboxylic acid such as phthalic acid, isophthalic acid, terephthalic acid, maleic acid, trimellitic acid or an acid anhydride thereof.

The amount of the acid component used is not particularly limited, but is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, based on 100% by mass of the monomer component when synthesizing the alkyd resin.

Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, 1,6-hexanediol, and 1, , 4-Cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol, butylethylpropanediol, 1,9-nonanediol, bisphenol A, dihydric alcohols such as bisphenol F, glycerin, trimethylolethane , Trimethylol propane, pentaerythritol and the like. These can be used alone or in combination of two or more.
Among these, it is preferable to use glycerin or pentaerythritol.

The amount of the polyhydric alcohol component used is not particularly limited, but is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, based on 100% by mass of the monomer component when synthesizing the alkyd resin.

Examples of the epoxy compound include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether, hydrided bisphenol A diglycidyl ether, and alkylene glycol diglycidyl ether. These can be used alone or in combination of two or more.
Among these, bisphenol A diglycidyl ether is preferable.

When the epoxy compound is used, the amount used is not particularly limited, but it is preferably 5 to 50% by mass with respect to 100% by mass of the monomer component in synthesizing the alkyd resin.

The unsaturated monomer is not particularly limited as long as a (meth) acrylic compound is used, and other unsaturated monomers may be used together with the (meth) acrylic compound.

Examples of the (meth) acrylic compound include methyl (meth) acrylate, ethyl (meth) acrylate, n- or iso-propyl (meth) acrylate, n-, iso- or tert-butyl (meth) acrylate, and hexyl (. Meta) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) (Meta) acrylic acid alkyl esters such as acrylates, cyclohexyl (meth) acrylates, phenyl (meth) acrylates, benzyl (meth) acrylates, isobornyl (meth) acrylates, glycidyl (meth) acrylates, dicyclopentanyl (meth) acrylates, Tetrahydrofurfuryl (meth) acrylate, allyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4 -Ali ring such as epoxycyclohexylpropyl (meth) acrylate and allyl glycidyl ether, aromatic ring, heterocycle or vinyl group-containing (meth) acrylic acid ester, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate. , Addition of hydroxyl group-containing (meth) acrylic acid ester such as 2-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate to ethylene oxide, propylene oxide, γ-butyrolactone or ε-caprolactone, glycerol, (Meta) acrylic acid ester containing multiple hydroxyl groups such as (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, m- or p. -Contains alkoxy groups (meth) such as methoxyphenyl (meth) acrylate, o-, m- or p-methoxyphenylethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-dicyclopentenoxyethyl (meth) acrylate. ) Acrylate ester, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylami Tertiary amino group and (meth) acryloyl group-containing monomers such as nobutyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, (meth) acrylamide, Examples thereof include primary or secondary amino group and (meth) acryloyl group-containing monomers such as butylaminoethyl (meth) acrylate, (meth) acrylonitrile, and (meth) acrylic acid. These can be used alone or in combination of two or more.

The amount of the (meth) acrylic compound used is preferably 10 to 100% by mass, more preferably 20 to 90% by mass, based on 100% by mass of the unsaturated monomer.

Examples of the other unsaturated monomers include heterocyclic basic monomers such as vinylpyrrolidone and vinylpyridine, vinyl monomers such as styrene, vinyltoluene, α-methylstyrene, vinyl acetate and vinyl propionate, and crotonic acid. , Monoester of a monobasic acid or a dibasic acid monomer such as maleic acid, fumaric acid and itaconic acid, and a monoester of a dibasic acid monomer such as monomethyl maleate, monoethyl maleate, monomethyl itaconate and monoethyl itaconate. These can be used alone or in combination of two or more.

The unsaturated monomer preferably contains methyl (meth) acrylate, n- or iso-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, styrene and the like.

The resin (A1) preferably has a structural unit derived from a (meth) acrylic compound, a structural unit derived from an alkyd resin, and a structural unit derived from an epoxy compound, and has 100 mass of structural units derived from the (meth) acrylic compound. The content of the structural unit derived from the alkyd resin is preferably 1 to 20 parts by mass, and the structural unit derived from the epoxy compound is preferably 5 to 10 parts by mass.
Further, the resin (A1) can easily form a coating film having an excellent balance due to corrosion resistance, water resistance, adhesion to a base material, particularly a non-ferrous metal base material or a stainless steel base material, and impact resistance. A resin having a bisphenol A structure is preferable.

As the component (A) containing the resin (A1), a commercially available product may be used. For example, Yuka Resin C-390AE (Yoshimura Oil Chemical Co., Ltd.), which is a water-dispersible alkyd-modified acrylic resin having a carboxy group and a bisphenol A structure. (Made by Co., Ltd.).

<Modified epoxy resin having a carboxy group (A2)>
The modified epoxy resin (A2) having a carboxy group is not particularly limited as long as it is a modified epoxy resin having one or more carboxy groups in one molecule. For example, a reaction product of a bisphenol type epoxy resin, a compound having at least two or more carboxy groups in the molecule, and a compound having a reactivity with a conventionally known epoxy group, or a bisphenol type epoxy resin in the molecule. Examples thereof include reaction products of a compound having an amino group and (meth) acrylic acid.
In order to obtain the resin (A2) having a carboxy group, for example, a compound having a carboxy group may be used as the bisphenol type epoxy resin, and a compound having a carboxy group may be used as the compound having reactivity with the epoxy group. Alternatively, a carboxy group may be generated when these are reacted, or after the reaction, modification may be performed so that the finally obtained resin has a carboxy group.

The resin (A2) is preferably a resin that does not contain an epoxy group from the viewpoint of storage stability. As for such a resin having no epoxy group, if it is a resin made from a compound having an epoxy group, a common name including "epoxy" is used, and therefore, similarly in the present invention, it does not have an epoxy group. Even if it is a resin, it is called "modified epoxy resin".

As the bisphenol type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol AD type epoxy resin are preferable, and a bisphenol A type epoxy resin is more preferable. These can be used alone or in combination of two or more.

Examples of the compound having at least two or more carboxy groups in the molecule include aliphatic polyvalent carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid and maleic acid, and phthalic acid. , Isophthalic acid, terephthalic acid, hemmellitic acid, trimellitic acid, trimesic acid, merophanic acid, planar acid, pyromellitic acid, merit acid, diphenic acid and other aromatic polyvalent carboxylic acids, hydride trimellitic acid, hydrogenation Examples thereof include alicyclic polyvalent carboxylic acids such as pyromellitic acid. These can be used alone or in combination of two or more.
Further, a polyvalent carboxylic acid obtained by reacting an anhydride of a compound having at least three or more carboxy groups in the molecule with polyethylene glycol monoalkyl ether can also be used. By using such a polyvalent carboxylic acid, the resin (A2) can be made into a self-emulsifying type resin.

The reaction between the bisphenol type epoxy resin and the compound having at least two or more carboxy groups in the molecule uses a conventionally known catalyst such as triphenylphosphine for 3 to 15 hours in the range of 70 to 200 ° C. There is a method of reacting to some extent.

The mixing ratio of the bisphenol type epoxy resin and the compound containing at least two or more carboxy groups in the molecule is such that the carboxy group is about 1.1 to 1.5 mol with respect to 1 mol of the epoxy group. It is preferable to mix with.

Examples of the compound having reactivity with the epoxy group include amines and carboxylic acids, and amines are preferable from the viewpoint of ease of reaction with the epoxy group. These can be used alone or in combination of two or more.

The amines are not particularly limited, and examples thereof include aliphatic amines, alicyclic amines, aromatic amines, aromatic aliphatic amines, monoamines such as heterocyclic amines, diamines, and the like, but they contain hydroxyl groups. Amines that do not are preferable.

The carboxylic acids are not particularly limited, and examples thereof include saturated or unsaturated, aliphatic, aromatic or alicyclic carboxylic acids, monovalent or polyvalent carboxylic acids, but carboxylic acids containing no hydroxyl group are preferable.

As a method for synthesizing the reaction product of the bisphenol type epoxy resin, the compound having at least two or more carboxy groups in the molecule, and the compound having reactivity with the epoxy group, for example, a method of reacting in multiple steps is used. Can be mentioned. More specifically, the resin having one or more carboxy groups in the molecule, which is obtained by reacting the bisphenol type epoxy resin with the compound having at least two or more carboxy groups in the molecule, and the epoxy. Examples thereof include a method of reacting a group with a reactive compound.

The mixing ratio of the epoxy resin having one or more carboxy groups in the molecule used in the reaction and the compound having reactivity with the epoxy group is such that the amines and carboxylic acids remain in the obtained resin (A2). Then, the corrosion resistance of the obtained rust-preventive coating film may decrease, and if the epoxy group remains in the obtained resin (A2), the storage stability of the present composition may decrease. The ratio is preferably such that the amines, carboxylic acids, and epoxy groups do not remain in the resin (A2) as much as possible. For example, the epoxy group and the reactive group are preferably 0.9 with respect to 1 mol of the epoxy group. The amount is about 1.3 mol, more preferably about 1 to 1.2 mol.

Examples of the compound having an amino group in the molecule include compounds similar to the amines, but monoamine is preferable from the viewpoint of reactivity with the epoxy group and storage stability of the obtained resin (A2). These amines may be used alone or in combination of two or more.

Examples of the (meth) acrylic acid include acrylic acid and methacrylic acid.

Further, as the reaction of the bisphenol type epoxy resin, the compound having an amino group in the molecule, and (meth) acrylic acid, these may be reacted collectively or may be reacted in multiple steps. In the latter case, the reactions may be carried out in any order, and examples thereof include the following methods.
Method (1): A method of reacting a bisphenol type epoxy resin with the amines and adding (meth) acrylic acid to the obtained reaction product. Method (2): With the amines and the (meth) acrylic acid. A method of reacting an adduct obtained by an addition reaction with a bisphenol type epoxy resin. Examples of these addition reactions include a Michael addition reaction.

The reaction between the bisphenol type epoxy resin and the amines in the method (1) can be carried out without solvent or in the presence of a solvent. As the solvent, a hydrophilic solvent is preferable because desolvation after the reaction is not required, cellosolves, propylene glycols and grime are more preferable, and propyl cellosolve, butyl cellosolve, t-butyl cellosolve, methoxypropanol, etc. Propoxypropanol is more preferred. The reaction temperature is preferably 50 to 120 ° C. in terms of good reactivity.

Next, in the method of addition-reacting the reaction product thus obtained with (meth) acrylic acid, for example, immediately after obtaining the reaction product, an addition reaction is carried out under a temperature condition of 50 to 120 ° C. Alternatively, the epoxy group in the reaction product may be further reacted with the amines, and then the reaction product and (meth) acrylic acid may be subjected to an addition reaction under a temperature condition of 50 to 120 ° C. May be good.

The addition reaction between the amines and (meth) acrylic acid in the method (2) can be carried out in the absence of a solvent or in the presence of a solvent. Here, it is preferable that the solvent is the hydrophilic solvent in that desolvation after the reaction is not required. The reaction temperature is preferably 50 to 120 ° C. in terms of good reactivity.
In these addition reactions, a catalyst may be used if necessary, and examples of the catalyst include sodium ethoxide and the like.

Next, as a method of reacting the adduct thus obtained with the bisphenol type epoxy resin, for example, a method of reacting the adduct with the bisphenol type epoxy resin under a temperature condition of 50 to 120 ° C. can be mentioned. ..

The mixing ratio of the amines and (meth) acrylic acid in the addition reaction is about 0.7 to 0.9 mol of the vinyl group of (meth) acrylic acid with respect to 1 mol of the amino group of the amines. It is preferable to mix them so as to be.

As for the mixing ratio of each component, if the amines remain in the obtained resin (A2), the corrosion resistance of the obtained rust-preventive coating film may decrease, and the obtained resin (A2) contains an epoxy group. If it remains, the storage stability of the composition may be lowered. Therefore, it is preferable that the ratio is such that the amines and epoxy groups do not remain in the obtained resin (A2) as much as possible, for example, 1 mol of epoxy group. On the other hand, the amount of amines is about 0.9 to 1.3 mol, more preferably about 1 to 1.2 mol.

As the component (A) containing the resin (A2), a commercially available product may be used. For example, Epicron C-250EP (DIC Corporation), which is an aqueous dispersion type modified epoxy resin having a carboxy group and a bisphenol A structure. Made).

<Aqueous epoxy resin (B)>
The component (B) may be a compound other than the component (A), and preferably has two or more epoxy groups in one molecule. The component (B) may be an emulsion or a dispersion, and the resin physical property values such as the molecular weight and epoxy equivalent of the epoxy resin are not particularly limited.
The component (B) contained in the present composition may be one kind or two or more kinds.

Examples of the component (B) include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin (for example, phenol novolac type epoxy resin, cresol novolac type epoxy resin), alicyclic epoxy resin, and aliphatic. Examples include modified epoxy resins.

The content of the epoxy resin in 100% by mass of the component (B) is preferably 35 to 100% by mass, more preferably from the viewpoint of obtaining a coating composition excellent in ease of preparation, storage stability and the like. Is 45 to 80% by mass.
The residue of the component (B) may contain water, and if necessary, a conventionally known component such as a surfactant may be contained.

As the component (B), a commercially available product may be used. For example, Epicron EM-85-75W and Epicron EM-8358 (both of which are water-dispersed bisphenol A type epoxy resins having no carboxy group). Examples thereof include DIC (manufactured by DIC Corporation) and Adecaledin C-110EP (manufactured by ADEKA Corporation).

The content of the non-volatile content of the component (B) is such that a coating film having an excellent balance can be easily formed due to corrosion resistance, water resistance, adhesion to a base material, particularly a non-ferrous metal base material or a stainless steel base material, and impact resistance. From this point of view, preferably 1 to 30 parts by mass, more preferably 1 to 25 parts by mass, still more preferably 5 to 20 parts by mass, and particularly preferably 5 to 5 parts by mass with respect to 100 parts by mass of the non-ferrous content of the component (A). It is 15 parts by mass.

<Water (C)>
The components (A) and (B) may contain water, and the components (A) and (B) preferably contain water, but the preparation of the present composition. It is preferable to further add water (C) to the present composition from the viewpoints of facilitating the above and improving the storage stability of the composition. When the present composition comprises a first agent containing the component (A) and a second agent containing the component (B), the ease of preparation and storage stability of the first agent and the second agent are further improved. From the viewpoint of improvement and the like, it is preferable to add the component (C) to the first agent and / or the second agent, and it is preferable to add the component (C) to the first agent and the second agent.
The component (C) is not particularly limited, and tap water or the like may be used, but ion-exchanged water or the like is preferably used.
The content of water in the present composition (total of water that can be contained in the components (A) and (B) and other water (C)) is not particularly limited, but is preferably 10 to 50% by mass. Is.

<Pigment (D)>
Examples of the component (D) include extender pigments, coloring pigments, rust preventive pigments (D1) and the like, and one type alone or two or more types can be used.
When the present composition is a multi-component composition consisting of a first agent and a second agent, the component (D) may be blended with either one of the first agent and the second agent, or both. It may be blended, but it is preferably blended in the first agent.

The content of the component (D) in the present composition can easily form a coating film having an excellent balance due to corrosion resistance, water resistance, adhesion to a base material, particularly a non-ferrous metal base material or a stainless steel base material, and impact resistance. From the above points, it is preferably 45 to 75% by mass, more preferably 50 to 70% by mass, based on 100% by mass of the non-ferrous content of the present composition.

With regard to the pigment volume concentration (PVC) in the present composition, a composition having excellent coating workability can be easily obtained, and a coating film having excellent adhesion to a substrate due to stress relaxation and water resistance can be easily obtained. From the viewpoint of being able to do so, it is preferably 20 to 50%, more preferably 20 to 45%, still more preferably 20 to 40%, and particularly preferably 20 to 38%.
If the PVC is below the above range, the corrosion resistance of the obtained coating film tends to be deteriorated and the effect of stress relaxation due to the addition of the pigment tends to be poor, and if it exceeds the above range, the impact resistance of the obtained coating film tends to be poor. As the property decreases, the painting workability tends to decrease.

The PVC refers to the total volume concentration of the pigment with respect to the volume of the non-volatile component in the present composition. Specifically, PVC can be obtained from the following formula.
PVC [%] = total volume of all pigments in this composition x 100 / volume of non-volatile content in this composition

The non-volatile content (solid content) of the present composition means the mass percentage of the coating film (heated residue) after the composition is sufficiently reaction-cured (heated), or the coating film (heated residue) itself. do. For the non-volatile content, 1 ± 0.1 g of the present composition (for example, the composition immediately after mixing the first agent and the second agent) was weighed in a flat-bottomed dish according to JIS K 5601-1-2: 2008. By spreading evenly using a wire of known mass, drying at 23 ° C for 24 hours, and then heating at a heating temperature of 125 ° C for 1 hour (under normal pressure), the heating residue and the mass of the wire are measured. Can be calculated. The non-volatile content is a value equivalent to the total amount of solid content (components other than the solvent) of the raw material components used in the present composition.

The volume of the non-volatile component in the present composition can be calculated from the mass and the true density of the non-volatile component of the present composition. The mass and true density of the non-volatile component may be measured values or values calculated from the raw materials used.
The volume of the pigment can be calculated from the mass and true density of the pigment used. The mass and true density of the pigment may be measured values or values calculated from the raw materials used. For example, it can be calculated by separating the pigment from other components from the non-volatile content of the present composition and measuring the mass and true density of the separated pigment.

<Constitution pigment>
The extender pigment is not particularly limited, but is a pigment other than the following coloring pigments and rust preventive pigments.
Examples of the extender pigment include conventionally known talc, mica, barium sulfate (including precipitated barium sulfate and barium sulfate), (potassium) feldspar, kaolin, alumina white, clay, magnesium carbonate, barium carbonate, and the like. Calcium carbonate, dolomite, silica can be mentioned. Among these, talc, barium sulfate, and (potassium) feldspar are preferable.
As the extender pigment, one kind may be used, or two or more kinds may be used.

When the extender pigment is blended in the present composition, a coating film having an excellent balance of corrosion resistance, water resistance, adhesion to a base material, particularly a non-ferrous metal base material or a stainless steel base material, and impact resistance can be easily obtained. From the viewpoint of being able to be formed, it is preferably 15 to 60% by mass, more preferably 20 to 55% by mass, based on 100% by mass of the non-ferrous content of the present composition.

<Coloring pigment>
The coloring pigment is not particularly limited, but is a pigment other than the following rust preventive pigments.
Examples of the coloring pigment include conventionally known inorganic pigments such as carbon black, titanium dioxide (titanium white), iron oxide (valve handle), yellow iron oxide, and ultramarine, and organic pigments such as cyanine blue and cyanine green. Be done. Among these, titanium white, carbon black, and valve handle are preferable.
As the coloring pigment, one kind may be used, or two or more kinds may be used.

When the coloring pigment is blended in the present composition, the content is preferably 0.1 to 25% by mass, more preferably 0.5 to 20% by mass, based on 100% by mass of the non-volatile content of the present composition. be.

<Rust preventive pigment (D1)>
The present composition preferably contains a rust preventive pigment (D1) as the component (D) from the viewpoint that a coating film having more excellent corrosion resistance and water resistance can be easily obtained.
As the component (D1), one kind may be used, or two or more kinds may be used.

The component (D1) is preferably a metal phosphate-based rust preventive pigment, and is preferably zinc phosphate-based, molybdenum phosphate-based, aluminum phosphate-based, or strontium phosphate-based, from the viewpoint that the above effects can be easily obtained. It is more preferable that it is a rust preventive pigment. More specifically, as these rust preventive pigments, for example, hydrate of aluminum molybdenum polyphosphate, hydrate of zinc aluminum molybdenate polyphosphate, aluminum phosphomolybdate, zinc strontium phosphate silicate, zinc molybdenum polyphosphate. Examples include hydrates, silicate hydrates of calcium polyphosphate strontium, silicate hydrates of zinc aluminum polyphosphate silicates, zinc phosphates, and organic modifications thereof, preferably of organically modified aluminum molybdenum polyphosphate. A hydrate, aluminum phosphate molybdenum, a hydrate of zinc polyphosphate molybdenum, and zinc phosphate.

When the component (D1) is blended in the present composition, a coating film having an excellent balance of corrosion resistance, water resistance, adhesion to a base material, particularly a non-ferrous metal base material or a stainless steel base material, and impact resistance is obtained. From the viewpoint of easy formation and the like, it is preferably 0.1 to 15% by mass, more preferably 1 to 15% by mass with respect to 100% by mass of the non-ferrous content of the present composition.
When the content of the component (D1) is lower than the above range, the corrosion resistance and water resistance of the obtained coating film tend to decrease, and when it exceeds the above range, the adhesion and impact resistance to the substrate are deteriorated. As it decreases, the water resistance tends to decrease.

<Other ingredients>
Further, in the present composition, in addition to the above-mentioned components, if necessary, a known dispersant, a film-forming auxiliary, an antifoaming agent, a thickener, an anti-sedimenting agent, as long as the effect of the present invention is not impaired. A dryer, a curing accelerator, an organic solvent and the like may be blended.

[Organic solvent]
Since the composition may freeze in winter due to the inclusion of water, the purpose of suppressing the freezing, the purpose of obtaining appropriate coating workability as a coating composition, and the like, etc. Therefore, an organic solvent that can be mixed with water in any amount can be used.
Examples of such an organic solvent include alcohol solvents having 1 to 3 carbon atoms such as isopropyl alcohol, ether solvents such as ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether.

≪Rust-proof coating film, base material with rust-preventive coating film≫
The rust-preventive coating film according to an embodiment of the present invention (hereinafter, also referred to as “the present coating film”) is formed by using the present composition, and is a group with a rust-preventive coating film according to the embodiment of the present composition. The material (hereinafter, also referred to as “base material with a coating film”) is a laminate containing the main coating film and an object to be coated (base material).

The material of the base material is not particularly limited, and is, for example, steel (eg, iron, steel, mild steel), non-ferrous metal (eg, aluminum, copper, brass, zinc plating, zinc spraying), stainless steel (eg, SUS304, etc.). SUS410), and the surface of the base material may be coated with a coating film formed from a coating composition such as an alkyd resin-based, an acrylic resin-based, or an epoxy resin-based coating composition.
Further, when mild steel (SS400 or the like) is used as the base material, the base material adjustment (eg, arithmetic mean roughness (Ra)) is 30 to 75 μm, for example, by polishing the base material surface with grit blast or the like, if necessary. It is desirable to adjust it so that it becomes a degree.

The base material is not particularly limited and can be used without limitation for a base material that is required to have corrosion resistance and water resistance, but it is preferable from the viewpoint that the effect of using this composition is more exhibited. , Bridges, tanks, plants, (land) structures such as (transport) containers.

The dry film thickness of this coating film is not particularly limited, but a coating film having sufficient corrosion resistance and water resistance and having excellent adhesion and impact resistance to a base material, particularly a non-ferrous metal base material or a stainless steel base material, is obtained in a well-balanced manner. From the viewpoint of being obtained, it is usually 10 to 100 μm, preferably 20 to 60 μm.

Further, the substrate with the coating film is a laminate containing the coating film and the object to be coated (base material), and even if a topcoat coating film having further excellent weather resistance and aesthetics is formed on the coating film. good. Examples of such a topcoat coating film include a coating film formed from various topcoat water-based coating compositions such as acrylic resin-based, acrylic silicon resin-based, urethane resin-based, silicone resin-based, and fluororesin-based.

≪Manufacturing method of base material with rust preventive coating film≫
The method for producing a base material with a rust-preventive coating film according to an embodiment of the present invention (hereinafter, also referred to as “the present method”) includes the following steps [1] and [2].
Step [1]: Step of applying the present composition to the substrate Step [2]: Step of drying the present composition coated on the substrate to form a rust-preventive coating film.

<Step [1]>
The coating method in the step [1] is not particularly limited, and examples thereof include conventionally known methods such as airless spray coating, spray coating such as air spray coating, brush coating, and roller coating. Among these, spray coating is preferable from the viewpoint that a large-area substrate such as the structure can be easily coated.
In such painting, it is preferable to paint so that the dry film thickness of the obtained coating film is within the above range.

The conditions for spray coating may be appropriately adjusted according to the dry film thickness to be formed. For example, in the case of airless spray coating, the primary (air) pressure: about 0.3 to 0.6 MPa, the secondary (paint). ) Pressure: preferably about 10 to 15 MPa and a gun moving speed of about 50 to 120 cm / sec.

The viscosity of this composition suitable for the spray coating is preferably 6 under the measurement conditions of 23 ° C. using a B-type viscometer (manufactured by Rion Co., Ltd., model VT-06) as a measuring instrument. It is 000 to 20,000 mPa · s, more preferably 8,000 to 12,000 mPa · s.

When painting the present composition, the viscosity of the coating composition may be adjusted to an appropriate level, if desired. It is preferable to use water as the diluent used for such viscosity adjustment.
In this case, it is preferable to use a diluent so as to have a coating viscosity suitable for each coating method. For example, in the case of airless spray coating, the amount of the diluent used per 100 parts by mass of the present composition is preferably 1 to 30. It is a mass part.

<Step [2]>
The drying conditions in the step [2] are not particularly limited and may be appropriately set according to the coating film forming method, the type of the base material, the application, the coating environment, etc., but the drying temperature is the case of normal temperature drying. It is usually 5 to 35 ° C., more preferably 10 to 30 ° C., and usually 30 to 90 ° C., more preferably 40 to 80 ° C. when dried with a hot air dryer or the like. According to this composition, the composition can be cured even by such room temperature drying.
On the other hand, the drying time varies depending on the drying method of the coating film, and is usually 1 hour to 7 days, preferably 1 day to 3 days in the case of normal temperature drying, and usually 5 minutes to 60 minutes in the case of drying with a hot air dryer or the like. Minutes, preferably 10 to 30 minutes.

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. The blending amount in the table represents "parts by mass" unless otherwise specified.
The raw materials used in the following Examples and Comparative Examples are shown in Table 1 below.

[Example 1]
In a container, 9.7 parts by mass of ion-exchanged water, 1 part by mass of dispersant, 0.1 part by mass of defoaming agent, 14 parts by mass of talc, 13 parts by mass of barium sulfate, and 10 parts by mass of titanium oxide. A mill base was prepared by adding 0.1 part by mass of a settling inhibitor and dispersing to a grain gauge of 40 μm or less (based on JIS K 5600-2-5: 1999) with a high-speed disper. To the obtained mill base, add 45 parts by mass of the aqueous resin A1, 1 part by mass of the film-forming auxiliary, 0.1 part by mass of the defoaming agent, and 1 part by mass of the thickener, and then mix them with a high-speed disper. , The first agent was prepared.
Further, 2.5 parts by mass of water-dispersed epoxy B1 and 2.5 parts by mass of ion-exchanged water were added to another container, and then mixed with a high-speed disper to prepare a second agent.
The obtained first agent and second agent were mixed immediately before coating to prepare a coating composition.

[Examples 2 to 19 and Comparative Example 2]
Each coating composition was prepared in the same manner as in Example 1 except that the raw materials shown in Tables 2 to 4 were used in the amounts shown in the table.

[Comparative Example 1]
In a container, 11.7 parts by mass of ion-exchanged water, 1 part by mass of dispersant, 0.1 parts by mass of defoaming agent, 11 parts by mass of talc, 11 parts by mass of barium sulfate, and 10 parts by mass of titanium oxide. Add 5 parts by mass of rust-preventive pigment 1 and 0.1 parts by mass of anti-settling agent, and disperse to a grain gauge of 40 μm or less (based on JIS K 5600-2-5: 1999) with a high-speed disper to make a mill base. Made. To the obtained mill base, 48 parts by mass of the aqueous resin A1, 1 part by mass of the film-forming auxiliary, 0.1 part by mass of the defoaming agent, and 1 part by mass of the thickener were added, and then mixed with a high-speed disper. , The coating composition of Comparative Example 1 was prepared.

[Comparative Example 3]
A coating composition was prepared in the same manner as in Comparative Example 1 except that the raw materials shown in Table 2 were used in the amounts shown in the table.

<Preparation of acrylic resin-based water-based paint>
In the container, 6 parts by mass of ion-exchanged water, 1 part by mass of dispersant, 0.1 part by mass of defoaming agent, 15 parts by mass of titanium oxide, 15 parts by mass of barium sulfate, and 0. 1 part by mass was added and dispersed with a paint shaker to a grain gauge of 30 μm or less (based on JIS K 5600-2-5: 1999) to prepare a mill base. To the obtained mill base, add 55 parts by mass of a water-dispersible acrylic resin, 4 parts by mass of a film-forming auxiliary, 0.1 parts by mass of an antifoaming agent, and 1 part by mass of a thickener, and then use a high-speed disperser. Acrylic resin-based water-based paint was prepared by mixing.

[How to make a test piece]
The viscosities of the coating compositions of Examples and Comparative Examples were adjusted using ion-exchanged water so that the viscosities at 23 ° C. measured using the B-type viscometer were 10,000 mPa · s.
Each coating composition after adjusting the viscosity is applied on a stainless steel sheet (SUS410) by air spray so that the average dry film thickness is 40 μm, dried at room temperature for 10 minutes, and then dried with hot air at 50 ° C. for 15 minutes. To form an undercoat coating film. Then, the acrylic resin-based water-based paint was applied onto the undercoat coating film by air spray so that the average dry film thickness was 40 μm, and the topcoat coating film was formed under the same drying conditions as the undercoat coating film. After forming the topcoat film, it was dried in an environment of 23 ° C. and a relative humidity of 50% for 7 days to prepare a test body (base material with a coating film) used for various coating film performance evaluation tests described later.
In this method, in order to promote drying, the undercoat film was formed by hot air drying at 50 ° C. for 15 minutes, but each coating film obtained in the examples was prepared at room temperature (23 ° C.) for 1.5 hours. The undercoat coating film (cured coating film) could also be formed by drying.

<Initial adhesion>
[Go board adhesion test]
Each of the test pieces was subjected to a grid adhesion test (cross-cut method) of 25 squares of 2 mm × 2 mm according to JIS K 5600-5-6: 1999, and the 25 squares occupy the test pieces according to the following evaluation criteria. Adhesion was evaluated by the ratio (%) of the area of the coating film peeled from the stainless steel plate to 100% of the coating film area.
It can be said that there is no practical problem in the adhesiveness if the following evaluation is "4" or higher.

(Evaluation criteria)
5: The area of the peeled coating film is 5% or less 4: The area of the peeled coating film is larger than 5% and 15% or less 3: The area of the peeled coating film is larger than 15% and 35% or less 2: The peeled coating film is peeled off The area of the coating film is larger than 35% and 65% or less 1: The area of the peeled coating film is larger than 65%

[Impact resistance test]
For each of the test pieces, an impact tester (manufactured by BYK-Gardener) was used to attach a 2-pound weight having a spherical tip (diameter: 0.625 inches) to the coating film surface (front) of the test piece. It was dropped from a height of 30 inches from the specimen. A cross-shaped cut is made 1.5 cm at a time around the falling part of the weight on the coating film surface until it reaches the base material (SUS410), and after attaching the transparent pressure-sensitive adhesive tape, the tape is peeled off and applied. The maximum peeling width of the film was measured. Impact resistance (impact resistance test (table)) was evaluated according to the following evaluation criteria.
Further, the weight is dropped on the surface (back side) opposite to the coating film surface of the test piece, and the maximum peeling width is measured on the coating film surface corresponding to the falling portion of the weight in the same manner as described above, and the following evaluation is performed. Impact resistance (impact resistance test (back)) was evaluated according to the criteria. The maximum peeling width refers to the length at which the line connected so as to pass through the center of the drop portion of the weight is the longest at the portion where the coating film is peeled off.
It can be said that there is no practical problem in impact resistance if the following evaluation is "3" or higher.

(Evaluation criteria)
5: The coating film did not peel off 4: The maximum peeling width of the coating film is 8 mm or less 3: The maximum peeling width of the coating film is larger than 8 mm and 12 mm or less 2: The maximum peeling width of the coating film is larger than 12 mm and 16 mm or less 1: The maximum peeling width of the coating film is larger than 16 mm

<Secondary adhesion>
After performing the salt spray test described later on each of the test pieces, the secondary adhesion of each test piece was evaluated according to the same test methods and evaluation criteria as those of the grid adhesion test and the impact resistance test.

<Water resistance>
[Water immersion test]
A water immersion test in which each test piece is immersed in water at 23 ° C. for 96 hours (4 days) or 168 hours (7 days) based on JIS K 5600-6-2: 1999 regarding liquid resistance (water immersion method). Was carried out. The water resistance was evaluated according to the evaluation criteria described later.
As for the water resistance, if the following evaluation of the test piece after being immersed in water for 96 hours is "3" or more, it can be said that there is no practical problem, and even after being immersed in water for 168 hours, the following evaluation is "3". In the above cases, it can be said that the undercoat coating film has extremely high water resistance.

(Evaluation criteria)
5: No rust or swelling occurred 4: No swelling occurred, but for the entire area of the painted surface of the test piece
Rust generation area is 0.03% or less 3: No swelling occurs, but with respect to the total area of the painted surface of the test piece
Rust generation area is larger than 0.03% and 0.1% or less 2: No swelling occurs, but with respect to the total area of the painted surface of the test piece
Rust generation area is greater than 0.1% and 0.3% or less 1: Swelling occurs and / or with respect to the total area of the painted surface of the test piece
, Rust generation area is larger than 0.3%

<Anti-corrosion property>
[Salt spray test]
Based on JIS K 5600-7-1: 1999 regarding neutral salt spray resistance, each of the above test specimens was placed in a salt spray tester under salt spray conditions of a salt water concentration of 5 wt%, a temperature of 35 ° C, and a relative humidity of 98%. A salt spray test was performed by holding for 200 hours. The anticorrosion property was evaluated by evaluating each test piece after this salt spray test according to the same evaluation criteria as in the water immersion test.
It can be said that there is no practical problem in the anticorrosion property if the evaluation is "3" or higher.

Even when the base material of the base material with a coating film (test piece) is changed from a stainless steel plate to an aluminum base material or a steel plate in each of the above tests, it can be obtained from the coating composition obtained in Examples in the same manner as described above. The coating film had excellent adhesion to these substrates.

It was found that this coating film is excellent in initial adhesion, secondary adhesion, water resistance and corrosion resistance. It was also found that this coating film has excellent adhesion to a base material, particularly a non-ferrous metal base material, a stainless steel base material, and an iron-based base material, and also has excellent adhesion to a topcoat coating film. When a conventional composition such as an alkyd resin is used, if the above-mentioned interval is insufficient, a coating film defect tends to occur due to lifting, but according to the present composition, the present coating film is formed. It was found that coating film defects such as lifting are unlikely to occur and a desired laminated coating film can be easily formed regardless of the range of the interval from the formation to the formation of the topcoat coating film.

Claims (9)

A first agent containing an aqueous resin (A) having one or more carboxy groups in one molecule, and
It is a multi-component type containing a second agent containing an aqueous epoxy resin (B) having two or more epoxy groups in one molecule other than the aqueous resin (A).
The aqueous resin (A) contains one or more selected from an aqueous alkyd-modified acrylic resin (A1) having a carboxy group and an aqueous modified epoxy resin (A2) having a carboxy group.
The content of the non-volatile component of the aqueous epoxy resin (B) is 1 to 20 parts by mass with respect to 100 parts by mass of the non-volatile content of the aqueous resin (A).
Aqueous rust preventive paint composition. The water-based rust-preventive coating composition according to claim 1, wherein the alkyd-modified acrylic resin (A1) and the modified epoxy resin (A2) are resins having a bisphenol A structure. The water-based rust-preventive coating composition according to any one of claims 1 to 2 , further comprising a pigment (D). The water-based rust-preventive coating composition according to claim 3 , wherein the pigment (D) contains a rust-preventive pigment (D1). The water-based rust-preventive paint composition according to claim 3 or 4 , wherein the pigment volume concentration (PVC) in the water-based rust-preventive paint composition is 20 to 50%. A rust-preventive coating film formed from the water-based rust-preventive paint composition according to any one of claims 1 to 5 . A base material with a rust-preventive coating film having the rust-preventive coating film and the base material according to claim 6 . The base material with a rust-preventive coating film according to claim 7 , wherein the base material is a non-ferrous metal or stainless steel. A method for producing a base material with a rust-preventive coating film, which comprises the following steps [1] and [2].
[1] Step of applying the water-based rust-preventive coating composition according to any one of claims 1 to 5 to a substrate [2] Drying the water-based rust-preventive coating composition coated on the substrate Step to form rust preventive coating