JP7429560B2 - Anticorrosive paint composition - Google Patents

Description

The present invention relates to an anticorrosive coating composition, a coating film, a substrate with a coating film, and a method for producing the same.

BACKGROUND ART Conventionally, base materials of land and marine structures such as bridges, tanks, plants, and (transportation) containers have been provided with anticorrosive coatings for the purpose of preventing corrosion. As an example of a paint that forms this anticorrosive coating, a zinc-rich paint containing a high content of zinc powder is used. As such a zinc-rich paint, a solvent-based paint using an organic solvent as a solvent is used from the viewpoint of corrosion resistance, painting workability, etc.

In recent years, regulations regarding the content of volatile organic compounds (VOC) have become stricter from the perspective of environmental conservation and work environment safety. A switch to paint is desired.

As such a water-based zinc-rich paint, Patent Document 1 describes a two-component, one-powder type water-based zinc-rich paint consisting of a base agent containing an epoxy resin emulsion, a pigment component (powder component) containing zinc dust, and an amine curing agent. Are listed.
Further, Patent Document 2 describes a zinc-rich paint containing an aqueous urethane resin.

JP2008-272666A Japanese Unexamined Patent Publication No. 7-133442

The conventional water-based zinc-rich paints described in Patent Documents 1 and 2 do not have sufficient drying properties and/or curing properties, and there is also room for improvement in terms of the corrosion resistance of the resulting coating film. .
In addition, conventional water-based zinc-rich paints using known amine-based curing agents, which have been used as curing agents for epoxy resins, as described in Patent Document 1, have drying, curing, and/or potability. There wasn't enough life, and there was room for improvement in this respect.

The present invention has been made in view of the above, and an object of the present invention is to provide an anticorrosive coating composition that can form a coating film with excellent anticorrosion properties and has excellent drying and curing properties.

As a result of intensive studies on methods for solving the above problems, the inventors have discovered that the above problems can be solved by using a specific coating composition, and have completed the present invention.
A configuration example of the present invention is as follows.

<1> A first agent containing an aqueous epoxy resin (A) having one or more carboxyl groups in one molecule and having an acid value of non-volatile content of 1 to 20 mgKOH/g;
a second agent containing zinc dust (B);
An anticorrosive paint composition comprising:
An anticorrosive coating composition containing 43 to 85% by mass of the zinc powder (B) based on 100% by mass of nonvolatile content of the anticorrosion coating composition.

<2> The anticorrosive coating composition according to <1>, wherein the aqueous epoxy resin (A) is an aqueous amine-modified epoxy resin (A1).
<3> The anticorrosive coating composition according to <1> or <2>, wherein the nonvolatile content of the aqueous epoxy resin (A) has an amine value of 1 to 150 mgKOH/g.

<4> The anticorrosive coating composition according to any one of <1> to <3>, wherein the second agent contains a glycol ether solvent or an alcohol solvent having 1 to 3 carbon atoms.

<5> The anticorrosive coating composition according to any one of <1> to <4>, wherein the second agent contains a binder other than the aqueous epoxy resin (A).

<6> The anticorrosive coating composition according to any one of <1> to <5>, wherein the content of volatile organic compounds (VOC) in 100% by mass of the anticorrosive coating composition is 10% by mass or less.

<7> A coating film formed from the anticorrosive coating composition according to any one of <1> to <6>.
<8> A coated base material comprising a base material and the coating film according to <7>.

<9> A method for producing a coated base material, including the following steps [1] and [2].
[1] A step of coating a substrate with the anticorrosive coating composition according to any one of <1> to <6>. [2] A step of drying the composition coated on the substrate to form a coating film.

According to the present invention, it is possible to provide a water-based anticorrosive coating composition that has excellent drying properties and hardening properties, zinc dust dispersibility, storage stability, and water dilutability, and has a long pot life. Further, according to the present invention, it is possible to provide a water-based anticorrosive coating composition that has excellent drying properties and curability without using a known amine curing agent that has been used as a curing agent for epoxy resins.
Further, according to the present invention, a coating film having excellent corrosion resistance and adhesion to a substrate can be formed.

≪Anti-corrosion paint composition≫
The anticorrosive coating composition according to the present invention (hereinafter also simply referred to as "the present composition") includes:
A first agent containing an aqueous epoxy resin (A) having one or more carboxyl groups in one molecule and having an acid value of non-volatile content of 1 to 20 mgKOH/g;
a second agent containing zinc dust (B),
This composition contains 43 to 85% by mass of the zinc dust (B) based on 100% by mass of the nonvolatile content of the present composition.

The present composition is not particularly limited as long as it is a multi-component composition containing the first agent and the second agent, and may include a third agent other than the first agent and the second agent depending on the components used. Although it may be a three-component or more composition, the present composition has excellent drying and curing properties, zinc powder dispersibility, and water dilutability even if it is not a three-component or more composition. It can be a two-component composition with a long pot life.

Therefore, the present composition is a multi-component composition containing a first part and a second part. A two-component composition consisting of a first agent and a second agent (only) is preferable.
This composition may be a one-part, one-powder type composition in which the first part is liquid and the second part is powder, and the first part and the second part are liquid (paste). A two-component composition may be used, but from the viewpoints of ease of handling at the painting site (miscibility of zinc powder) and ease of storage of the second component, A two-component composition is preferred.

These first to third agents (hereinafter collectively referred to as "nth agent") are usually stored, stored, transported, etc. in separate containers, and are used at the time of painting (e.g. immediately before painting). ) to form the present composition. In other words, these nth agents can be said to be components of a kit for preparing the present composition. In other words, the present composition is an anticorrosive paint composition containing the first agent and the second agent. It can be said that it is a kit for supplies.
In the present invention, the nth agent is an agent that can be stored after the preparation of these agents until the preparation of the present composition. Since it is mixed with other ingredients and used shortly after preparation, it does not correspond to the nth agent in the present invention.

The present composition is prepared by mixing the n-th agent, but after or during this preparation, it may be diluted and used depending on the coating method and the like.
Each explanation in this specification is an explanation before being diluted, except for the content regarding the dilution.

Since the present composition contains the water-based epoxy resin (A), it is usually a water-based paint composition. The aqueous coating composition refers to a composition in which components such as a resin (A) and zinc dust (B) are dispersed and/or dissolved in water or a medium containing water as a main component (aqueous medium).
The content of water in the aqueous coating composition is preferably 50% by mass or more, preferably 60 to 100% by mass, more preferably 65 to 100% by mass, based on 100% by mass of the total amount of the dispersion medium and solvent in the composition. Mass%.

The environment in which paint is applied to base materials such as containers may not have sufficient drying equipment. In such an environment, when applying conventional water-based zinc-rich paints, emphasis is placed on drying properties, and organic solvents have been blended into the paints.
On the other hand, according to the present invention, a coating composition with excellent drying and curable properties can be obtained, so even without incorporating an organic solvent, a desired coating film can be easily formed in places where drying equipment is insufficient. can be formed into
Therefore, from the viewpoint of environmental protection and work environment safety, the content of volatile organic compounds (VOC) in 100% by mass of this composition is preferably 10% by mass or less, more preferably 8% by mass or less. The VOC content in the present composition is preferably 200 g/L or less, more preferably 180 g/L or less.

The VOC content in the present composition can be calculated from the following formulas (1) and (2) using the values of composition specific gravity, heating residual fraction (mass ratio of nonvolatile components), and moisture content. Note that the composition specific gravity, heating residual fraction, and moisture content may be the following measured values or values calculated from the raw materials used.
VOC content (mass%) = (100 - heating residual fraction - moisture percentage) / 100... (1)
VOC content (g/L) = Composition specific gravity x 1000 x (100 - heating residual fraction - moisture percentage) / 100... (2)

Composition specific gravity (g/ml): Under a temperature condition of 23 ° C., fill a specific gravity cup with an internal volume of 100 ml with this composition (the composition immediately after mixing the nth agent), and calculate the mass of the composition. The value calculated by

Heating residual fraction (mass%): Weigh out 1 ± 0.1 g of the present composition (composition immediately after mixing the nth agent) and each component into a flat-bottomed dish, and spread it evenly using a wire with a known mass. Mass percentage value calculated by measuring the heating residue (non-volatile content) and the mass of the wire when heated at a heating temperature of 125° C. for 1 hour (under normal pressure).

Moisture content (mass %): The value of the mass percentage of water contained in 100 mass % of the present composition, measured by the Karl Fischer method.

This composition can be applied to iron and steel (iron, steel, ferroalloy, carbon steel, mild steel, alloy steel, etc.), nonferrous metals (zinc, aluminum, copper, brass, galvanized, zinc sprayed, etc.), stainless steel (SUS304, SUS410, etc.) ), and is particularly suitable for steel base materials.
Further, the present composition is suitably used for (large) steel structures such as ships, offshore structures, plants, bridges, tanks, and containers.

<First agent>
The first agent of the present composition is not particularly limited as long as it contains the aqueous epoxy resin (A), but since it contains the resin (A), it is usually a liquid agent containing water.
The content of water in the first part is preferably 50% by mass based on 100% by mass of the total amount of the dispersion medium and solvent in the first part, in order to easily obtain the desired aqueous coating composition. The amount is at least 70% by mass, more preferably 70 to 100% by mass, particularly preferably 80 to 100% by mass.

The first agent may contain other ingredients, such as a binder other than the resin (A), water, pigments (e.g. extender pigments, coloring pigments), rust preventives, flash rust prevention agents, to the extent that the effects of the present invention are not impaired. agents, dispersants, antifoaming agents, destabilizing agents (anti-sagging/anti-settling agents), leveling agents, wetting agents, thickeners, film forming aids, dryers, fibrous substances, surfactants, organic solvents, preventive agents. Conventionally known components such as fungicides, preservatives, ultraviolet absorbers, light stabilizers, and pH adjusters may be appropriately blended as needed.
Each of these may be used alone or in combination of two or more.

[Aqueous epoxy resin (A)]
The resin (A) is not particularly limited as long as it is an aqueous epoxy resin having one or more carboxyl groups in one molecule and having an acid value of nonvolatile content of 1 to 20 mgKOH/g.
As the resin (A), one type may be used, or two or more types may be used.

Because such resin (A) is used, even if the VOC content is within the above range or the composition is a two-component type, the composition has excellent drying properties, curability, storage stability, and pot life. It is possible to easily form a coating film that is excellent in corrosion resistance, water resistance, adhesion to substrates, and impact resistance in a well-balanced manner.
Moreover, by using such a resin (A), a coating film can be formed without using a conventional amine-based curing agent that has been used as a curing agent for epoxy resins. Therefore, it is preferable that the amine curing agent is not used in the present composition, from the viewpoint of obtaining a composition with excellent drying properties, curability, and pot life.
Furthermore, when the first agent contains a pigment, the resin (A) having a carboxyl group tends to have an affinity for the pigment, so that improvement in the dispersibility of the pigment is expected. Therefore, improvement in production efficiency due to improvement in pigment dispersibility can be expected.

In the present invention, "aqueous resin" refers to water, a resin that uses water as a main solvent or dispersion medium, or a resin that is mixable with water (dilutable with water), and more specifically, a water-based resin that is water-based. Examples include mold resins, water-soluble resins, and self-emulsifying resins. Such aqueous resins can be produced by conventionally known methods, such as solution polymerization, suspension polymerization, emulsion polymerization, seed polymerization, miniemulsion polymerization, microemulsion polymerization, and emulsifier-free (soap-free) emulsion polymerization. It can be synthesized with etc. In addition to these methods, the aqueous resin can also be obtained by emulsifying the resin by known methods such as phase inversion emulsification, D-phase emulsification, forced emulsification, gel emulsification, inversion emulsification, and high-pressure emulsification.

Note that even for resins that do not have epoxy groups, if the resin is made from a compound that has epoxy groups, a common name that includes "epoxy" is used, so the "epoxy resin" in the present invention also includes epoxy. Contains resins without groups.

The epoxy equivalent of the non-volatile content of the resin (A) is preferably 1500 or more, more preferably 2000 or more, from the viewpoint of easily obtaining a composition with better drying properties and/or curability. It is particularly preferable that (A) does not have an epoxy group.
The epoxy equivalent can be measured according to JIS K 7236:2001.

The acid value of the nonvolatile content of the resin (A) is 20 mgKOH/g or less, preferably 15 mgKOH/g or less, more preferably 10 mgKOH/g or less, even more preferably 9 mgKOH/g or less, particularly preferably 8 mgKOH/g or less, and It is preferably 7 mgKOH/g or less, 1 mgKOH/g or more, preferably 1.5 mgKOH/g or more, particularly preferably 2 mgKOH/g or more.
By using the resin (A) having an acid value within the above range, a composition with better drying properties and/or curability can be easily obtained, and a coating film with excellent anticorrosion properties can be easily formed.
The acid value can be measured in accordance with JIS K 0070:1992.

The amine value of the non-volatile content of the resin (A) is preferably 150 mgKOH/g or less, more preferably 100 mgKOH/g or less, particularly preferably 75 mgKOH/g or less, preferably 1 mgKOH/g or more, more preferably 25 mgKOH/g. g or more, particularly preferably 50 mgKOH/g or more.
By using the resin (A) having an amine value within the above range, a composition with better drying properties and/or curability can be easily obtained, and a coating film with excellent anticorrosion properties can be easily formed.
The amine value can be measured according to JIS K 7273:1995.

The resin (A) that satisfies the epoxy equivalent (not having an epoxy group), acid value and/or amine value as described above may include an epoxy resin (a1) and a conventionally known compound having reactivity with an epoxy group ( a2) (provided that the reaction product has one or more carboxy groups in the molecule).

As the compound (a2) having reactivity with the epoxy group, amines are preferable from the viewpoint of ease of reaction with the epoxy group.
The compound (a2) can be used alone or in combination of two or more.

The amines are not particularly limited, and include monoamines and polyamines such as aliphatic amines, alicyclic amines, aromatic amines, araliphatic amines, and heterocyclic amines. The amines may be used alone or in combination of two or more.

The amines are not particularly limited, and include, for example, primary alkylamines such as butylamine, octylamine, oleylamine, and 2-ethylhexylamine, and primary alkanolamines such as monoethanolamine, 2-ethoxyethanolamine, and 2-hydroxypropanolamine. aliphatic polyamines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, alicyclic polyamines such as 1,3-diaminocyclohexane and isophoronediamine, aromatic polyamines such as diaminodiphenylmethane, o-xylene diamine, Mannich bases consisting of aromatic aliphatic amines such as m-xylene diamine and p-xylene diamine, polycondensates of polyamines, aldehyde compounds, and monohydric or polyhydric phenols; polyamines and polycarboxylic acids and dimer acids; Examples include polyamide polyamines obtained by the reaction, polyoxyalkylene amines such as polyoxyethylene amine, and polyoxypropylene amine. From the standpoint of excellent dispersibility in aqueous media and storage stability, primary alkylamines, primary alkanolamines, and polyoxyalkylene amines are preferred, and primary alkanolamines and polyoxyalkylene polyamines are more preferred.

Examples of the polyoxyalkylene amines include compounds represented by the following structural formula (a2-1).

（式中、Ｒ¹は、水素原子、メチル基、エチル基、プロピル基、またはｔ－ブチル基であり、Ｒ²は独立に、エチレン基、１，２－プロピレン基、２，３－プロピレン基、１，３－プロピレン基であり、Ｒ³はメチレン基、エチレン基、１，２－プロピレン基、２，３－プロピレン基、１，３－プロピレン基であり、ｎは繰り返し単位の平均値を意味し、２～１００である。）

(In the formula, R ¹ is a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a t-butyl group, and R ² is independently an ethylene group, a 1,2-propylene group, a 2,3-propylene group. , 1,3-propylene group, R ³ is a methylene group, ethylene group, 1,2-propylene group, 2,3-propylene group, 1,3-propylene group, and n is the average value of repeating units. 2 to 100)

The molecular weight of the polyoxyalkylene amines is preferably a weight average molecular weight (Mw) of 300 to 5,000, more preferably 300 to 5,000, from the viewpoint of easily obtaining a composition with excellent storage stability and anticorrosion properties. is 400 to 1,500.

Commercial products may be used as the polyoxyalkylene amines, and examples of the commercial products include "Jeffamine M-600" (weight average molecular weight: 600), "Jeffamine M-1000" (weight average molecular weight: 600), "Jeffamine M-1000" (weight average molecular weight: 600), Molecular weight: 1,000), "Jeffamine M-2005" (weight average molecular weight: 2,000), "Jeffamine M-2070" (weight average molecular weight: 2,000) (all manufactured by Huntsman) Can be mentioned. Among these, "Jeffamine M-600" and "Jeffamine M-1000" are preferred.

The resin (A) obtained using the above amines can be said to be an aqueous amine-modified epoxy resin (A1). By using the resin (A1), a composition with better drying properties and curability can be easily obtained, and a coating film with better corrosion resistance and adhesion to substrates can be easily formed.
Note that the modified epoxy resin in the present invention refers to a resin in which the monomer components constituting the epoxy resin exceed 50% by mass based on 100% by mass of all the monomer components constituting the resin.

The epoxy resin (a1) is preferably a bisphenol type epoxy resin from the viewpoint of the toughness of the resulting coating film and its adhesion to the substrate, and bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, etc. Resins are preferred, and bisphenol A epoxy resins are more preferred.
The epoxy resin (a1) can be used alone or in combination of two or more.

In order for the reaction product to be a resin having one or more carboxyl groups in the molecule, a compound having a carboxyl group may be used as the epoxy resin (a1), and a compound having a carboxyl group as the compound (a2) may be used. A compound may be used, and a carboxyl group may be generated when these are reacted, or after reacting these, modification etc. may be performed so that the resin finally obtained has a carboxyl group. However, it is preferable to use an unsaturated carboxylic acid (a3) other than the epoxy resin (a1) and compound (a2) in the reaction.

Examples of the unsaturated carboxylic acid (a3) include (meth)acrylic acid. These can be used alone or in combination of two or more.

The order in which the epoxy resin (a1), the compound (a2), and the unsaturated carboxylic acid (a3) are reacted is not particularly limited, but it is possible to easily obtain a resin that satisfies the acid value and amine value as described above. From this point, the epoxy resin (a1) and the compound (a2) are reacted (hereinafter also referred to as "reaction 1"), and then the compound obtained in reaction 1 and the unsaturated carboxylic acid (a3) are reacted ( (hereinafter also referred to as "reaction 2") is preferred.
These reactions 1 and 2 can be performed by conventionally known methods.

The mixing ratio of the epoxy resin (a1) and the compound (a2) in the reaction 1 is determined depending on the mixing ratio of the epoxy resin (a1) and the compound (a2), since if the epoxy group remains in the resulting resin (A), the storage stability of the composition may decrease. The ratio is preferably such that no epoxy groups remain as much as possible in the resin (A), for example, the amount of amino groups is preferably about 1.1 to 1.5 mol per 1 mol of epoxy groups. The amount is preferably about 1.1 to 1.3 moles.

In the reaction 2, the mixing ratio of the compound obtained in the reaction 1 and the unsaturated carboxylic acid (a3) is such that when the amino group remains in the resulting resin (A), the corrosion resistance of the resulting coating film increases. may decrease, so the amount of carboxy group is preferably about 1.1 to 1.5 mol per 1 mol of amino group, and it is preferable to mix so that the amount is about 1.1 to 1.3 mol. More preferred.

As the resin (A), a commercially available product may be used, such as EPICLON C-250EP (manufactured by DIC Corporation), which is an aqueous amine-modified epoxy resin having a bisphenol A structure and one or more carboxyl groups in one molecule. ), epoxy group-free, acid value: 5.7 mgKOH/g, amine value: 60 mgKOH/g).

The nonvolatile content of the resin (A) relative to 100% by mass of the nonvolatile content of the present composition is such that it is possible to easily obtain a composition with excellent drying properties and curability, and to maintain a good balance between corrosion resistance and adhesion to substrates. The content is preferably 5 to 30% by mass, more preferably 6 to 20% by mass, from the standpoint of being able to easily form an excellent coating film.

The content of non-volatile matter (resin) in 100% by mass of the resin (A) is preferably 30 to 75% by mass, from the viewpoint of obtaining a composition with better preparation ease, storage stability, etc. More preferably, it is 35 to 60% by mass.
The remainder of the resin (A) only needs to contain water, and may contain conventionally known components such as a surfactant, if necessary.

[water]
Although the resin (A) may contain water, water may be added to the first part in order to facilitate the preparation of the present composition and obtain a composition with excellent coating workability. It is preferable to blend.
The water is not particularly limited, and tap water or the like may be used, but it is preferable to use ion exchange water or the like.
The content of water in the first agent (including water that may be contained in the resin (A), etc.) is not particularly limited, but is preferably 20 to 70% by mass.

[Stirring agent (anti-sagging/anti-settling agent)]
The present composition preferably contains a stimulant in order to improve thick coating properties and anti-sagging properties during coating, and to prevent sedimentation of insoluble substances such as zinc dust (B) and pigments in water and organic solvents. In particular, since this composition has excellent drying properties, cracks are likely to occur when forming a thick film (e.g. 80 μm or more), but by using a modifier, the occurrence of cracks can be suppressed. I can do it.
As the modifier, one type may be used, or two or more types may be used.

Examples of the modifier include organic clay salts such as stearate salts of Al, Ca, and Zn, lecithin salts, and alkyl sulfonates, oxidized polyethylene waxes, ethylene/vinyl acetate waxes, polyamide waxes, and hydrogenated waxes. Examples include castor oil wax and synthetic fine powder silica. Among these, organic swaying agents such as oxidized polyethylene waxes, ethylene/vinyl acetate waxes, and polyamide waxes are preferred because they can easily form a coating film with excellent crack resistance.

The nonvolatile content of the stimulant based on 100% by mass of the nonvolatile content of the present composition is preferably 0.01 to 3.5% by mass, from the viewpoint of easily forming a coating film with excellent crack resistance. More preferably, it is 0.05 to 3% by mass.

[Dispersant]
This composition improves the dispersibility of zinc powder (B), pigments, etc. in the composition, and can easily form a cured film with a good appearance, and can easily form a coating film with excellent crack resistance. From this point of view, it is preferable to contain a dispersant.
As the dispersant, one type may be used, or two or more types may be used.

Dispersants include, but are not particularly limited to, pigment adsorption groups such as carboxy groups, phosphoric acid groups, amino groups, salt groups thereof, and ammonium bases, and include fatty acids, polyaminos, polyethers, polyesters, polyurethanes, Examples include various dispersants such as copolymers having compatible chains such as polyacrylate.

The nonvolatile content of the dispersant based on 100% by mass of the nonvolatile content of the present composition is preferably 0.1 to 3% by mass, more preferably It is 0.1 to 2.5% by mass.

[Flash last prevention agent]
When a water-based paint is applied to an active steel surface, a flash occurs in which rust occurs and the rust appears on the surface of the paint film due to iron ions being eluted from the surface of the steel material immediately after painting and during the drying process. The last thing may happen. In particular, the occurrence of flash last may be noticeable under high temperature and high humidity conditions.
In order to suppress such flash last, it is preferable to use a flash last inhibitor in the present composition.
As the flash last inhibitor, one type may be used, or two or more types may be used.

Examples of flash last inhibitors include nitrites such as sodium nitrite, potassium nitrite, calcium nitrite, strontium nitrite, barium nitrite, and ammonium nitrite; sodium benzoate, potassium benzoate, calcium benzoate, and ammonium benzoate. benzoates such as; phytates such as sodium phytate and potassium phytate; fatty acid salts such as sebacic acid and dodecanoic acid; phosphoric acid derivatives such as alkyl phosphoric acid and polyphosphoric acid; tannates; Hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), propylenediaminetetraacetic acid (PDTA), iminodiacetic acid, nitrilotriacetic acid (NTA), diethylenetriaminepentamethylenephosphonic acid (DTPMP) ), amine-based chelating agents such as these alkali metal salts; addition reaction products of 4-methyl-γ-oxo-benzenebutanoic acid and N-ethylmorpholine; monoalkylamines, polyamines, quaternary ammonium ions, etc. Examples include intercalation compounds formed by intercalating layered phosphates such as aluminum dihydrogen; hydrazine derivatives such as hydrazide compounds, semicarbazide compounds, and hydrazone compounds.

Among these, nitrites (e.g., metal salts such as sodium, potassium, calcium, ammonium salts), benzoates (e.g., sodium, potassium, calcium, etc.) have excellent flash rust resistance and are inexpensive. metal salts, ammonium salts) are preferred, nitrites are more preferred, and sodium nitrite is particularly preferred because a composition exhibiting high flash last resistance can be easily obtained even if the amount used is small. .

The content of the flash rust inhibitor based on 100 mass % of the nonvolatile content of the present composition is preferably 0.01 to 2 mass %, more preferably It is 0.05 to 1.0% by mass.

[Organic solvent]
When the first agent contains water, an arbitrary amount of a water-miscible organic solvent may be used in order to suppress freezing in winter and to obtain a composition with better coating workability.
As the organic solvent, one type may be used, or two or more types may be used.
Examples of such organic solvents include alcohol solvents having 1 to 3 carbon atoms such as isopropyl alcohol and ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl. Examples include glycol ether solvents such as ether and propylene glycol monoethyl ether.

<Second agent>
The second agent of the present composition is not particularly limited as long as it contains zinc dust (B), and may consist essentially only of the zinc dust (B), as long as it does not impair the effects of the present invention. It may contain components other than the zinc powder (B).
These other components may be used alone or in combination of two or more.

[Zinc dust (B)]
The zinc powder (B) is a metallic zinc powder or an alloy mainly composed of zinc (zinc content is 90% by mass or more of the total) (e.g., at least one selected from zinc and aluminum, magnesium, and tin). Examples include powders of alloys with seeds, preferably zinc-aluminum alloys, zinc-tin alloys).
As zinc dust (B), one type may be used, or two or more types may be used.

The shape of the zinc powder (B) is not particularly limited, but the median diameter (D50) is preferably 2 to 15 μm, more preferably 2 to 15 μm, since a coating film with better corrosion resistance can be easily obtained. Particulate zinc dust having a diameter of 7 μm is preferred.
The D50 can be measured using a laser scattering diffraction particle size distribution analyzer, for example, "SALD 2200" (manufactured by Shimadzu Corporation).

The content of zinc dust (B) based on 100% by mass of the nonvolatile content of the present composition is 43 to 85% by mass, and is preferably 45% by mass from the viewpoint of easily obtaining a coating film with better corrosion resistance. ~85% by weight, more preferably 50-85% by weight, particularly preferably 65-82% by weight.
If the content of zinc powder (B) is less than 43% by mass, the sacrificial anode effect of zinc will be insufficient and the corrosion resistance will tend to deteriorate, and if it exceeds 85% by mass, the pigment content in the dried coating film will be reduced. becomes excessive, which tends to cause a decrease in water permeability.

Components other than the zinc dust (B) include the same components as the other components listed in the column of the first agent.
As mentioned above, the second agent is preferably liquid (paste-like), and in this case, the second agent has excellent dispersibility of the zinc dust (B) and excellent miscibility with the first agent. It is preferable that an organic solvent is included because it is possible to easily obtain the present composition in which the zinc dust (B) is uniformly dispersed.
As a specific example of such an organic solvent, the same organic solvents as those mentioned in the section of the first agent are preferable.
In addition, since the reaction between zinc dust (B) and water will reduce corrosion resistance due to oxidation of zinc dust (B) and increase the risk of fire due to the generation of hydrogen, the second agent should not be used with water. Preferably, it does not contain.

The content of the organic solvent in the second agent is preferably such that the amount of VOC in the composition falls within the above range. It is preferably 1 to 10% by weight, more preferably 3 to 8% by weight based on 100% by weight.

Further, the second agent preferably contains a swaying agent for the same reason as above and from the viewpoint of transportability and storage stability of the second agent, and as the swaying agent, the first agent Examples include the same stimulants as the stimulants listed in the section above.

[Binder other than resin (A)]
The second agent preferably contains a binder other than the resin (A), and more preferably a compound that is reactive with the resin (A). Examples of such compounds include epoxy resins, isocyanate-based curing agents, carbodiimide-based curing agents, and epoxy group-containing silane coupling agents. Epoxy resins are particularly preferred.

The epoxy resin preferably has two or more epoxy groups in one molecule, and the resin physical properties such as molecular weight and epoxy equivalent are not particularly limited, but the VOC content of the composition is It is preferable to be liquid at room temperature (23° C.) from the viewpoint of suppressing the increase.
In addition, when using the said epoxy resin, it is preferable to use it together with the said organic solvent from points of miscibility with zinc dust (B), etc.
These epoxy resins may be used alone or in combination of two or more.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin (e.g., phenol novolac type epoxy resin, cresol novolac type epoxy resin), alicyclic epoxy resin, and fatty acid-modified epoxy resin. can be mentioned. Among these, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable because a coating film with better corrosion resistance can be easily obtained, their viscosity is low, and the second agent has excellent workability. .

As the epoxy resin, a commercially available product may be used, and examples of the commercially available product include jER828 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, acid value : <1 mgKOH/g) and jER807 (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin, acid value: <1 mgKOH/g).

When such an epoxy resin is contained, the content of the resin is preferably set to 100% by mass of the non-volatile content of the present composition, from the viewpoint of easily obtaining a coating film with better corrosion resistance. is 0.1 to 10% by weight, more preferably 0.5 to 5% by weight.

<Method for preparing anticorrosion paint composition>
The first agent and the second agent can be prepared by mixing (kneading) the respective components to be added to these agents, and during this mixing (kneading), each component is added/mixed at once. They may be mixed, or may be added and mixed in multiple batches.
The present composition can be prepared by mixing (kneading) these first agent, second agent, and other agents (eg, third agent) used as necessary.
During the mixing (kneading), conventionally known devices such as mixers, dispersers, stirrers, etc. can be used, such as dispers, mixing/dispersing mills, mortar mixers, rolls, paint shakers, homogenizers, etc. can be mentioned. The mixing (kneading) may be performed while heating, cooling, etc. depending on the season, environment, etc.
Moreover, when preparing the present composition by mixing each of the above-mentioned agents, the content of zinc dust (B) in the resulting composition may be adjusted and mixed so that it falls within the above-mentioned range.

≪Coating film, base material with coating film≫
The coating film according to the present invention (hereinafter also referred to as "main coating film") is formed using the above-mentioned composition, and the coating film according to the present invention (hereinafter also referred to as "substrate with main coating film") is formed using the above-mentioned composition. ) is a laminate having a main coating film and a base material.

The material of the base material is not particularly limited, and includes, for example, steel (iron, steel, ferroalloy, carbon steel, mild steel, alloy steel, etc.), non-ferrous metals (zinc, aluminum, copper, brass, galvanized, zinc sprayed, etc.). etc.), stainless steel (SUS304, SUS410, etc.).
In addition, when using mild steel (SS400, etc.) as the base material, if necessary, the surface of the base material may be polished by grit blasting or the like to adjust the base material (for example, the arithmetic mean roughness (Ra) is 30 to 75 μm). It is desirable to adjust it to a certain degree.
The base material may be a base material that has been subjected to pretreatment such as cleaning or blasting treatment to remove rust, dirt, paint (old paint film), etc. that have adhered to the base material.

The base material is not particularly limited and can be used without any restriction for base materials that require anti-corrosion properties, but ships, ships, Examples include (steel) structures such as offshore structures, plants, bridges, tanks, and containers.

The dry thickness of the coating film is not particularly limited, but from the viewpoint of obtaining a coating film with sufficient anticorrosion properties, it is usually 10 to 100 μm, preferably 15 to 80 μm, and more preferably 20 to 60 μm.

The base material with the main coating film is a laminate containing the main coating film and the base material, and on top of the main coating film, an intermediate coating film is added for the purpose of improving corrosion resistance, weather resistance, aesthetics, etc. It may also form an excellent top coat. Examples of the intermediate coating film include coating films formed from various intermediate coating compositions such as acrylic resin, epoxy resin, and urethane resin. Examples of the top coat film include those formed from various top coat compositions such as acrylic resin, acrylic silicone resin, urethane resin, silicone resin, and fluorine resin.

≪Method for manufacturing base material with coating film≫
The method for producing a coated substrate according to the present invention (hereinafter also referred to as "the present method") includes the following steps [1] and [2].
Step [1]: Step of coating the present composition on a substrate Step [2]: Step of drying the present composition coated on the substrate to form a coating film.

<Step [1]>
The coating method in step [1] is not particularly limited, and examples thereof include conventionally known methods such as spray coating such as airless spray coating and air spray coating, brush coating, and roller coating. Among these, spray coating is preferred because it can easily coat large-area base materials such as the above-mentioned structures.
In such coating, it is preferable to apply the coating so that the dry film thickness of the resulting coating film falls within the above range.

The spray coating conditions may be adjusted as appropriate depending on the desired dry film thickness. 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 gun movement speed of about 50 to 120 cm/sec.

In addition, when coating the present composition, the viscosity of the coating composition may be adjusted to an appropriate value as 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 to obtain a paint viscosity suitable for each coating method. For example, in the case of airless spray painting, the amount of diluent used per 100 parts by mass of the present composition is preferably 1 to 30 parts by mass. Parts by weight, more preferably 1 to 20 parts by weight.

The viscosity of this composition (composition diluted if necessary) suitable for the above-mentioned spray coating was determined using a B-type viscometer (manufactured by Rion Co., Ltd., model VT-06) at 23°C. The viscosity below is preferably 3,000 to 15,000 mPa·s, more preferably 5,000 to 12,000 mPa·s.

<Step [2]>
The drying conditions in step [2] are not particularly limited and may be set appropriately depending on the coating film formation method, type of substrate, application, coating environment, etc., but the drying temperature is when drying at room temperature. The temperature is usually 5 to 35°C, more preferably 10 to 30°C, and when forced drying with a hot air dryer etc., the temperature is usually 30 to 90°C, more preferably 40 to 80°C. According to the present composition, the composition can be cured even by drying at room temperature.
The drying time varies depending on the drying method of the coating film, and in the case of drying at room temperature, it may be about 1 to 7 days like conventional paints, but according to the present composition, it is preferably 3 hours to 12 hours. The drying time can be more preferably 5 hours to 10 hours. In addition, when forced drying, it may take about 5 to 60 minutes like conventional paints, but according to the present composition, it is preferably 5 to 30 minutes, more preferably 10 to 20 minutes. Can be dried.

The present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

[Example 1]
In a container, 18.1 parts by mass of ion exchange water, 2 parts by mass of dispersant 1, 0.5 parts by mass of antifoaming agent, 0.3 parts by mass of flash last inhibitor, 8 parts by mass of extender, and , 1.5 parts by mass of thixotropic agent 1 was added and dispersed with a high-speed disperser to a grain size of 40 μm or less to prepare a mill base. After adding 63 parts by mass of water-dispersed epoxy resin A, 2.5 parts by mass of a film-forming agent, 0.1 parts by mass of a leveling agent, and 4 parts by mass of a thickener to the obtained mill base, high speed The first agent of Example 1 was prepared by mixing with a disper.
Next, 40 parts by mass of the first part obtained as described above and 60 parts by mass of zinc powder, which is the second part, were mixed with a high-speed disperser until uniform. was prepared.

[Example 2]
A first agent was prepared in the same manner as in Example 1.
Next, 7 parts by mass of an organic solvent, 2 parts by mass of dispersant 2, 3 parts by mass of thixotropic agent 2, 1 part by mass of wetting agent, and 87 parts by mass of zinc powder were added to the container, and high speed The second agent of Example 2 was prepared by mixing with a disper.
Thereafter, 30 parts by mass of the first part and 70 parts by mass of the second part were mixed using a high-speed disperser until they became uniform, thereby preparing the coating composition of Example 2.

[Example 3]
A first agent was prepared in the same manner as in Example 1.
Next, in a container, 5 parts by mass of an organic solvent, 2 parts by mass of dispersant 2, 3 parts by mass of thixotropic agent 2, 1 part by mass of a wetting agent, 2 parts by mass of a binder other than the resin (A), and 87 parts by mass of zinc powder was added and mixed using a high-speed disperser to prepare the second agent of Example 3.
Thereafter, 30 parts by mass of the first part and 70 parts by mass of the second part were mixed using a high-speed disperser until they became uniform, thereby preparing the coating composition of Example 3.

[Examples 4 to 7 and Comparative Examples 5 to 7]
A coating composition was prepared in the same manner as in Example 2, except that each of the raw materials listed in Table 2 was used in the amounts listed in the table.

[Comparative example 1]
A first agent was prepared in the same manner as in Example 1, except that each of the raw materials listed in Table 1 was used in the amounts listed in the table.
Next, 45 parts by mass of a water-soluble amine, 0.2 parts by mass of an antifoaming agent, and 54.8 parts by mass of ion-exchanged water were added to the container, and then mixed with a high-speed disper. A curing agent was prepared.
Thereafter, 30 parts by mass of the first part, 5 parts by mass of the curing agent, and 65 parts by mass of zinc dust as the second part were mixed with a high-speed disper until uniform, to prepare the coating composition of Comparative Example 1. did.

[Comparative Examples 2 to 4]
Each coating composition was prepared in the same manner as in Example 1 except that each raw material listed in Table 1 was used in the amount listed in the table.

The numerical value in the column for each agent (first agent, second agent, or curing agent) in Tables 1 and 2 represents "parts by mass."
Details of the raw materials in Tables 1 and 2 are shown in Table 3.

<1. Zinc dust miscibility test>
(1) Zinc powder miscibility test by manual stirring 160 parts by mass of the second agent used in each example and comparative example was placed in a container, and water and the resin used in the first agent of each test example were mixed into a container. Add so that the total is 40 parts by mass (however, if no curing agent is used, use an amount that makes the nonvolatile content of the resin used in each test example 15 parts by mass [for example, in the case of Example 1 , using 35.7 parts by mass of water-dispersed epoxy resin A (42% non-volatile content) and 4.3 parts by mass of water].In the case of Comparative Example 1, water-dispersed epoxy resin B (52% non-volatile content) was used. A mixture of 24.6 parts by mass and 3.0 parts by mass of a water-soluble amine (75% non-volatile content) with 12.4 parts by mass of water was stirred for 5 minutes using a spatula (hand stirring). Subsequently, the degree of dispersion of the zinc powder was measured using a particle gauge (0 to 100 μm) in accordance with JIS K 5600-2-5; 1999.

(2) Zinc powder miscibility test using disper stirring In the same manner as in (1) above, except that instead of manual stirring, stirring was performed for 5 minutes using a high-speed disper (rotation speed: 1000 rpm) (disper stirring). was measured.

Based on the dispersion degree of zinc powder measured in the tests (1) and (2) above, the miscibility of zinc powder was evaluated according to the following criteria.
・Evaluation criteria ○: Dispersity in the test (1) above is less than 30 μm △: Dispersity in the test (1) above is 30 μm or more, and dispersity in the test (2) above is less than 30 μm ×: The degree of dispersion in the test (2) above is 30 μm or more

<2. Drying test>
Each of the coating compositions of Examples and Comparative Examples was applied onto a glass plate at 23° C. using an applicator with a gap of 0.075 mm, and the drying state over time was measured. The drying property was evaluated based on JIS K 5600-1-1:1999 based on the time required for the dry state of the coated film surface to reach a semi-cured dry state. The "semi-cured and dry" state refers to a state where no scratches are left on the paint film by gently and lightly rubbing the center of the paint film surface with your fingertips.
・Evaluation criteria ○: A semi-cured and dry state was reached in 30 minutes or less. ×: A semi-cured and dry state was not reached even after 30 minutes had passed.

<3. Curing test>
The coating compositions of Examples and Comparative Examples were applied onto a glass plate (200 mm x 180 mm x 3 mm thickness) at 23°C using an applicator with a gap of 75 μm, and after standing for 10 minutes, the coating composition was heated at 50°C. A test specimen for hardening test was prepared by force drying for 10 minutes at room temperature, and then allowing it to stand at room temperature for one day. The scratch hardness (pencil method) of the coating film of the test specimen was measured based on JIS K 5600-5-4:1999. The hardest pencil hardness without any scratches on the surface of the coating film was defined as the coating hardness, and evaluation was made according to the following evaluation criteria.
・Evaluation criteria ○: Pencil hardness is 2B or more (Example: 2B, B, HB...)
×: Pencil hardness is less than 2B (e.g. 3B, 4B, 5B...)

<4. Pot life test>
Weigh out 1000 g of the composition immediately after preparing each coating composition of Examples and Comparative Examples (hereinafter also referred to as "coating composition (immediately)") and each coating composition of Examples and Comparative Examples into a container, The paint condition and coating hardness were observed or measured using the paint composition after being kept in a constant temperature bath at 35° C. for 5 hours (hereinafter also referred to as "paint composition (after 5 hours)").
The state of the paint composition (after 5 hours) was visually observed (presence of precipitation or agglomeration).
In addition, coating film hardness was evaluated according to the following evaluation criteria based on the difference in pencil hardness measured using the coating composition (immediately) or the coating composition (after 5 hours) in the same manner as the curing test. did.
・Evaluation criteria ○: There is no precipitation or agglomeration in the coating composition (after 5 hours), and the hardness of the coating film obtained from the coating composition (immediately) and the coating film obtained from the coating composition (after 5 hours) are There is no difference between the hardness of the paint film obtained from the paint composition (immediately after 5 hours), or the hardness of the paint film obtained from the paint composition (immediately after 5 hours). There was a difference in the hardness of the paint film obtained from the paint composition (after 5 hours).

<5. Water dilubility test>
After adding and mixing 15 parts by mass of water to 100 parts by mass of each coating composition of Examples and Comparative Examples, a glass plate (200 mm x 150 mm x 2 mm thick) placed on a horizontal stand at 23 ° C. ), using a sag tester (manufactured by Elcometer, model: 4270, gap 100-600 μm) as described in ASTM D 4400, and immediately place the glass plate so that the trajectory line of the sag tester becomes horizontal. The anti-sagging property was measured by standing it vertically. If the composition flowing out into the gap (3 mm) between the paint layers formed by each gap of the sag tester does not reach 1/2 of the gap distance (the composition drips from the paint layer formed by the sag tester) When the length did not reach 1.5 mm), it was determined that no sag occurred, and when the gap distance reached 1/2 of the gap distance, it was determined that sagging occurred.
In addition, anti-sagging property refers to the maximum film thickness (thickness of a wet coating film applied to a glass plate (sag tester gap)) when the flowing out composition does not reach 1/2 of the gap distance. The water dilutability was evaluated based on the difference between the anti-sagging property when diluted by 15% and the anti-sagging property when the coating composition was mixed (without dilution).
・Evaluation criteria ○: Difference in anti-sagging properties between undiluted and 15% dilution is within 250 μm ×: Difference in anti-sagging properties between undiluted and 15% diluted exceeds 250 μm

<6. Corrosion resistance test>
Each of the coating compositions of Examples and Comparative Examples was adjusted using ion-exchanged water so that the anti-sagging property measured in the same manner as the water dilubility test was 50 μm.
Each paint composition thus adjusted was applied by air spray onto a blast-treated steel plate (SS400, dimensions: 150 mm x 70 mm x 1.6 mm (thickness)) so that the average dry film thickness was 30 μm, After drying at room temperature for 10 minutes, a coating film was formed by drying with hot air at 50° C. for 10 minutes. Thereafter, a test specimen (base material with a coating film) was created by drying it for 7 days in an environment of 23° C. and 50% relative humidity.

Based on JIS K 5600-7-1:1999, each test specimen was kept in a salt spray tester for 24 hours under the conditions of salt water concentration 5wt%, temperature 35°C, and relative humidity 98%. A spray test was conducted. Each test piece after this salt spray test was evaluated according to the following evaluation criteria.
-Evaluation Criteria ○: The area where rust occurs is 0.03% or less of the total area of the coating surface of the test piece, and no blistering occurs in the coating film.
×: The area where rust occurred exceeded 0.03% of the total area of the coating surface of the test piece, or blistering occurred in the coating film.

Claims (8)

An anticorrosive paint composition, comprising:
A first agent containing an aqueous epoxy resin (A) having one or more carboxyl groups in one molecule and having an acid value of non-volatile content of 1 to 20 mgKOH/g;
a second agent containing zinc dust (B);
Contains
The zinc powder (B) is contained in an amount of 43 to 85% by mass based on 100% by mass of the non-volatile content of the anticorrosive coating composition,
The amine value of the nonvolatile content of the aqueous epoxy resin (A) is 1 to 150 mgKOH/g.
Anticorrosive paint composition. The anticorrosive coating composition according to claim 1, wherein the aqueous epoxy resin (A) is an aqueous amine-modified epoxy resin (A1). The anticorrosive coating composition according to claim 1 or 2 , wherein the second agent contains a glycol ether solvent or an alcohol solvent having 1 to 3 carbon atoms. The anticorrosive coating composition according to any one of claims 1 to 3 , wherein the second agent contains a binder other than the aqueous epoxy resin (A). The anticorrosive coating composition according to any one of claims 1 to 4 , wherein the content of volatile organic compounds in 100% by mass of the anticorrosive coating composition is 10% by mass or less. A coating film formed from the anticorrosive coating composition according to any one of claims 1 to 5 . A coated base material comprising a base material and the coated film according to claim 6 . A method for producing a coated substrate, including the following steps [1] and [2].
[1] A step of coating a substrate with the anticorrosive coating composition according to any one of claims 1 to 5. [2] A step of drying the composition coated on the substrate to form a coating film.