JP2021167379A - Coating material, and coated steel material - Google Patents

Abstract

To provide a coating material capable of imparting high corrosion resistance to a steel material or the like, and to provide a coated steel material obtained by using the same.SOLUTION: A coating material contains a powder and a binder. The powder contains at least one kind of metal sulfate selected from a group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate and manganese sulfate, and at least one kind of metal selected from a group consisting of zinc and zinc alloy. A mass ratio of at least the one kind of metal sulfate to the total mass of the powder and the binder is 0.1-60.0 mass%, and a mass ratio of at least the one kind of metal to the total mass of the powder and the binder is 1.0-95.0 mass%. When a mass of the powder in the coating material is A, and a mass of the binder is B, B/A≤0.5 is satisfied.SELECTED DRAWING: Figure 1

Description

The present invention relates to paints and coated steel materials. More specifically, the present invention is applied to a steel material, a steel material covered with a rust layer due to oxidation / corrosion, or a steel material covered with an organic layer or an inorganic layer (hereinafter, collectively referred to as a steel material). This relates to a paint for enhancing the corrosion resistance of the steel material, and further to a steel material (coated steel material) on which the paint is applied to form a coating film.

It is generally known that forming an oxide layer having a high environmental barrier property on the surface of a steel improves the corrosion resistance of the steel. For example, stainless steel forms a passivation film, which is an oxide layer with high environmental barrier properties, and exhibits high corrosion resistance. However, stainless steel is expensive, has problems in corrosion resistance such as pitting due to being a high alloy steel, and is inferior in mechanical properties such as strength and toughness as compared with low alloy steel. There are many restrictions when using it for structures and machines.

Further, the weathering steel obtained by adding a small amount of elements such as P, Cu, Cr and Ni is rust that is protective against corrosion (protective rust) as the corrosion progresses when it is placed outdoors. It is a low alloy steel that can improve the corrosion resistance of steel in the atmosphere and reduce the need for subsequent anticorrosion treatment work such as painting. However, it takes a long period of about 10 years or more for such weathering steel to form protective rust, and floating rust such as red rust or yellow rust or flowing rust due to corrosion at the initial stage during the above period. Not only is it unfavorable in appearance, but there is also the problem that significant damage such as a decrease in plate thickness due to corrosion occurs. In particular, in an acidic environment or a severe corrosive environment containing chloride, protective rust is not even formed, and sufficient corrosion resistance may not be ensured. In order to solve the above problem, for example, Patent Document 1 proposes a surface treatment method for forming a phosphate film on a steel material.

On the other hand, as a general means for ensuring the corrosion resistance of the steel material, coating the surface of the steel material can be mentioned. However, coating cannot prevent the deterioration of the coating film and the progress of corrosion from coating film defects even in a general corrosive environment, and merely delays the progress of corrosion. For example, there are coating methods such as zinc rich primer or zinc rich paint that utilize the sacrificial anticorrosive effect of zinc powder, but similarly, the effect can be exhibited only in a relatively short period of time. , Deterioration of the coating film and progress of corrosion from coating film defects cannot be essentially prevented. Further, if the zinc powder content is increased or the coating film is thickened too much to enhance the sacrificial anticorrosion effect, the adhesion to the steel material or the workability is significantly impaired. To solve such a problem, Patent Document 2 discloses that the corrosion resistance can be improved by applying an inorganic zinc rich paint to a steel material and applying a solution containing an Mg compound to the surface of the coating film.

Further, Patent Document 3 and Patent Document 4 also disclose a coating material to be applied onto a steel material. The paints disclosed in these are different from the above-mentioned paints which cannot prevent the deterioration of the paint film and the progress of corrosion from the paint film defects. In a steel material having a coating film formed from the above paint on the surface, an oxide layer having corrosion resistance is formed at an early stage at the interface between the coating material and the steel material due to the corrosion reaction of the steel material after the coating material is formed, and the steel material is formed by this oxide layer. Corrosion resistance is obtained.

Further, Patent Documents 5 and 6 disclose rust preventive coating materials containing oxides and hydroxides of alkaline earth metals.

Japanese Unexamined Patent Publication No. 1-142088 Japanese Unexamined Patent Publication No. 2017-358777 Japanese Unexamined Patent Publication No. 2001-234369 International Publication No. 2014/020665 International Publication No. 2019/069722 International Publication No. 2019/069724

However, the surface treatment method disclosed in Patent Document 1 cannot obtain sufficient anticorrosive properties, and although it can cope with a general corrosive environment, it cannot cope with an acidic environment or a severe corrosive environment containing chlorides. .. In addition, another pretreatment needs to be performed before the phosphate film is formed, which complicates the treatment process. In addition, many rust stabilization auxiliary treatment materials used for the same surface treatment method have been developed, but they essentially assist the anticorrosion function of low alloy steel, and are in an acidic environment or a severe corrosion environment containing chlorides. Cannot be supported.

Further, with respect to the treatment disclosed in Patent Document 2, the improvement ratio of the improvement in corrosion resistance with respect to no treatment is only about 3 times at most, and even if it can be said that it can cope with a general corrosive environment, it is an acidic environment. Alternatively, it could not be said that sufficient corrosion resistance was imparted in a severe corrosive environment containing chloride.

In addition, such zinc rich paint is applied to the surface of clean steel materials obtained by performing shot blasting, etc., and is applied to steel materials covered with a rust layer due to oxidation and corrosion to provide high corrosion resistance. It does not indicate.

The oxide layer formed at the interface between the coating film and the steel material disclosed in Patent Documents 3 and 4 showed high corrosion resistance and was sufficiently compatible with a general corrosive environment, but was in an acidic environment or It could not be said that it could sufficiently cope with the severe corrosive environment containing chloride.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coating material capable of imparting high corrosion resistance to a steel material or the like and a coated steel material obtained by using the coating material.

The first coating material according to the present invention contains a powder and a binder.
The powder is
At least one metal sulfuric acid selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. With salt
Includes at least one metal selected from the group consisting of zinc and zinc alloys.
The mass ratio of the at least one metal sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
When the mass of the powder in the paint is A and the mass of the binder is B, B / A ≦ 0.5 is satisfied.

Here, the first paint can further satisfy either of the following conditions 1 and 2.
Condition 1: The mass ratio of the at least one metal to the total mass of the powder and the binder is 40% by mass or more and less than 70% by mass, and B / A ≦ 0.4 is satisfied.
Condition 2: The mass ratio of the at least one metal to the total mass of the powder and the binder is less than 70% by mass, and B / A ≦ 0.3 is satisfied.

The second coating material according to the present invention contains a powder and a binder. The powder contains nickel sulfate and at least one metal selected from the group consisting of zinc and zinc alloys.
The mass ratio of the nickel sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
The powder does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.

The third coating material according to the present invention includes a powder and a binder.
The powder is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. One kind of metal sulfate and
Includes at least one metal selected from the group consisting of zinc and zinc alloys.
The ratio of the at least one kind of metal sulfate is 0.07 mol or more with respect to 100 g of the at least one kind of metal.
The powder does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.

The first coated steel material according to the present invention includes a steel material and a coating film formed on the surface of the steel material.
The coating film contains a powder and a binder, and the powder is:
At least one metal sulfuric acid selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. With salt
Includes at least one metal selected from the group consisting of zinc and zinc alloys.
The mass ratio of the at least one metal sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
When the mass of the powder in the coating film is A and the mass of the binder is B, B / A ≦ 0.5 is satisfied.
The thickness of the coating film is 10 to 300 μm.

The second coated steel material according to the present invention includes a steel material and a coating film formed on the surface of the steel material. The coating film contains a powder and a binder, and the powder contains nickel sulfate and at least one metal selected from the group consisting of zinc and zinc alloys.
The mass ratio of the nickel sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
The powder does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.
Further, the thickness of the coating film is 10 to 300 μm.

The third coated steel material according to the present invention includes a steel material and a coating film formed on the surface of the steel material. The coating film contains a powder and a binder.
The powder is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. One kind of metal sulfate and
Includes at least one metal selected from the group consisting of zinc and zinc alloys.
The ratio of the at least one kind of metal sulfate is 0.07 mol or more with respect to 100 g of the at least one kind of metal.
It does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide. Further, the thickness of the coating film is 10 to 300 μm.

Here, each coating steel, the coating film topcoat coating provided can further comprise on top of the topcoat coating film, the dry film thickness 100μm, 300g / (m 2 · 24h) or less permeable Can have humidity.

The fourth coated steel material according to the present invention includes a steel material, a coating film formed on the surface of the steel material, and a topcoat coating film provided on the coating film. The coating film contains a powder and a binder.
The powder is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. One kind of metal sulfate and
Includes at least one metal selected from the group consisting of zinc and zinc alloys.
The topcoat coating film, the dry film thickness 100 [mu] m, with a 300g ^/ (m 2 · 24h) or less moisture permeability.
The powder may not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.

According to the present invention, it is possible to provide a coating material capable of imparting high corrosion resistance to a steel material or the like in an acidic environment or a severe corrosion environment containing chloride, and a coated steel material obtained by using the coating material.

1 (a) is a cross-sectional view of a steel material according to an embodiment of the present invention, FIG. 1 (b) is a cross-sectional view of a coated steel material according to an embodiment of the present invention, and FIG. 1 (c) is the present invention. The cross-sectional view of the corrosion-resistant steel structure which concerns on one Embodiment is shown. FIG. 2A is a cross-sectional view of a plated steel material according to another embodiment of the present invention, FIG. 2B is a cross-sectional view of a coated steel material according to another embodiment of the present invention, FIG. 2C. Shows a cross-sectional view of a corrosion resistant steel structure according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described.
(First Embodiment)
The coating material according to the first embodiment is a coating material containing a powder and a binder.

(powder)
Powder is
At least one metal sulfuric acid selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. With salt
Includes at least one metal selected from the group consisting of zinc and zinc alloys.

(Metal sulfate)
The metal sulfate is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. It is one kind, and may include any plurality of kinds among these.

Each of the above-mentioned metal sulfates has sufficient solubility in water, that is, the amount dissolved in 100 g of water is 0.5 g or more at 5 ° C. It should be noted that calcium sulfate and the like have almost no effect because of their low solubility in water. Among these, the metal sulfate preferably contains nickel sulfate and / or aluminum sulfate.

The mass ratio of at least one metal sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%, and may be 1.0 to 30.0 mass%. The lower limit may be 0.5% by mass, 1% by mass, 2% by mass, 3% by mass, or 4% by mass. The upper limit may be 50% by mass, 40% by mass, 30% by mass, 20% by mass, and 15% by mass.

(metal)
The metal is at least one metal selected from the group consisting of zinc and zinc alloys, and may contain a plurality of types. Examples of zinc alloys are zinc aluminum alloys and zinc magnesium alloys.

The mass ratio of at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%. The lower limit may be 3% by mass, 10% by mass, 20% by mass, 30% by mass, or 35% by mass. The upper limit may be 90% by mass, 85% by mass, 80% by mass, 75% by mass, 70% by mass, and 65% by mass.

(Other components in powder)
The powder may contain components other than the above-mentioned metal sulfate and metal, if necessary.
Examples of other components are pigments and oxides or hydroxides of alkaline earth metals.

Examples of pigments are color pigments, extender pigments, rust preventive pigments, and special functional pigments.

Examples of oxides or hydroxides of alkaline earth metals are calcium oxide, calcium hydroxide, barium oxide, barium hydroxide, strontium oxide, strontium hydroxide.

The mass ratio of the pigment to the total mass of the powder and the binder may be 0.10 to 80.0% by mass, 1.0 to 70.0% by mass, and 10.0 to 45. It may be 0% by mass.

The mass ratio of the oxide or hydroxide of the alkaline earth metal to the total mass of the powder and the binder may be 0.10 to 50.0% by mass, and 1.0 to 45.0% by mass. It may be 10.0 to 45.0% by mass.

The powder may also contain phosphoric acid. The mass ratio of phosphoric acid to the total mass of the powder and the binder may be 10.0% by mass or less, 0.3 to 10.0% by mass, or 0.6 to 10.0% by mass. It may be 1.0 to 10.0% by mass.

(Powder form)
The powder is usually a mixture of metal sulfate powder, metal powder, and powder of additional components added as needed (eg, pigment powder and alkali earth metal oxide or hydroxide powder). Is. However, some or all of the powder may be particles containing a plurality of constituents. For example, one particle may contain both metal sulfate and metal.

The average particle size of the powder can be 1-40 μm and may be 5-20 μm.

In the present specification, the "average particle size" is an average particle size measured as follows, unless otherwise defined. First, a paint containing powder is applied to a polished steel sheet so as to form a dry coating film of 100 μm or more, and then dried. The cross section of the coating film after drying is observed by SEM (Scanning Electron Microscope). A total of 200 fixed-direction maximum diameters are obtained for each particle observed in the image, and the arithmetic mean thereof is taken as the average particle size.

(Binder)
The binder according to the present embodiment binds powders to each other and a base material such as a powder and a steel material. An example of a binder is a resin. The resin is not particularly limited, and is not particularly limited, and is vinyl butyral resin (polyvinyl butyral resin, etc.), epoxy resin, modified epoxy resin, acrylic resin, urethane resin, nitrocellulose resin, vinyl resin (polyvinyl chloride, polyvinyl acetate, and polyvinyl alcohol). Etc.), phthalic acid resin, melamine resin, fluororesin and the like. These resins may be thermoplastic resins or thermosetting resins. When the resin is a thermosetting resin, the coating material can further contain a curing agent if necessary, and the coating material usually cures during and after drying. The weight average molecular weight of the thermosetting resin is not particularly limited, but is about 200 to 20000. The weight average molecular weight of the thermoplastic resin is not particularly limited, but is about 1000 to 500000.

In the paint, the resin can form a continuous phase in which the powder is dispersed, with a solvent added as needed.

(Mixing ratio of powder and binder)
When the mass of the powder in the coating material is A and the mass of the binder is B, the coating material of the present embodiment satisfies B / A ≦ 0.5.
From the viewpoint of adhesion, the lower limit of B / A may be 0.01, 0.02, 0.05, 0.08, and 0.10. If the B / A is too small, the adhesion between the film and the steel material and the continuity of the film may be poor.

(solvent)
The paint according to this embodiment may further contain a solvent. Examples of the solvent include aromatic solvents such as xylene and toluene, alcohols having 3 or more carbon atoms such as isopropyl alcohol and normal butanol, and non-aqueous solvents such as ester solvents such as ethyl acetate; water, methyl alcohol and ethyl alcohol. Such as water-based solvents can be mentioned. Further, the resin may be a resin that dissolves in the solvent, may be a resin that dissolves in a non-aqueous solvent, or may be a resin that dissolves in an aqueous solvent.

In the present specification, the viscosity of the coating material is measured by a B-type viscometer at 20 ° C. The viscosity of the coating material is appropriately selected depending on the coating method, and can be, for example, 200 to 1000 cps. The content of the solvent in the coating material can be adjusted so that the viscosity of the coating material is within the above range.

(Ingredients other than powder, binder, and solvent)
The paint can further include additives such as thixotropic agents, dispersants, coupling agents, and antioxidants. The mass ratio of the additive may be 10.0% by mass or less with respect to the total mass of the powder and the binder.

(Preferable aspect)
In the present embodiment, it is preferable that the paint further satisfies either the following condition 1 or condition 2.
Condition 1: The mass ratio of the metal to the total mass of the powder and the binder is 40% by mass or more and less than 70% by mass, and B / A ≦ 0.4 is satisfied.
Condition 2: The mass ratio of the metal to the total mass of the powder and the binder is less than 70% by mass, and B / A ≦ 0.3 is satisfied. Further, it is preferable to satisfy B / A ≦ 0.2.
In condition 1 and condition 2, the upper limit of the mass ratio of the metal may be 65% by mass or less, or 60% by mass or less.

(Action)
When the coated steel material is exposed to a corrosive environment in a state where the metal sulfate and the powder containing the metal coexist in the coating film, the metal sulfate dissolves in water and dissociates into metal ions and sulfate ions. Sulfate ions dissolve zinc-based metals in powder to generate zinc ions (including Al and Mg ions in the case of zinc alloys). In addition, steel materials placed in a corrosive environment are dissolved by a corrosive reaction to generate iron ions. The corrosion reaction of the steel material tends to be suppressed by the sacrificial anticorrosive action of the zinc-based metal, but the presence of the metal sulfate assists the progress of the corrosion reaction of the steel material.

A thin iron rust layer mainly composed of iron ions is formed along with the corrosion reaction of steel materials by the sacrificial anticorrosion action and the assistance of the corrosion reaction by metal sulfate. At the same time, zinc ions (including Al and Mg ions in the case of alloy powder) and sulfate ions are also incorporated into the rust layer, and this rust layer functions as an anticorrosion rust layer.

When the residual rust layer already exists on the surface of the steel material, the residual rust layer is also changed to the anticorrosion rust layer by the effect of the above ions.
The iron rust layer formed in this way has high corrosion resistance. In particular, when a defective portion (crack or scratch) is present in the coating film, it is possible to suppress the generation of red rust in the defective portion, the outflow of rust juice from the defective portion, and the local corrosion of the defective portion.

In particular, if the coating film has defective parts such as cracks and scratches, the coating film does not exist in the defective parts and the steel material is exposed. Therefore, the corrosion reaction of the steel material is early from the moment the steel material is exposed to the corrosive environment. Starts.

Here, when B / A> 0.5 in the paint, the mass B of the binder is larger than the mass A of the powder by a certain amount or more, so that the metal and the powder containing metal sulfate or the like are bound. The agent will be thickly covered and the time required for the metal and metal sulfate to begin to dissolve will be longer. In particular, when the dissolution of the metal sulfate is delayed, the expression of the function of forming an iron rust layer having high corrosion resistance is particularly delayed. As a result, red rust having low corrosion resistance is generated in the defective portion of the coating film, and corrosion damage tends to proceed until an iron rust layer having high corrosion resistance is formed.

On the other hand, when B / A ≤ 0.5 in the paint and the coating film, the binder that covers the metal and the metal sulfate is thin, so there is no significant delay from the start of the corrosion reaction of the steel material in the defective part. , The reaction of metal and metal sulfate and the formation of anticorrosive iron rust layer are started in the surrounding coating film, and the iron rust layer with high anticorrosion property is formed at an early stage even in the defective part of the coating film. It is possible to improve the anticorrosive property in the defective portion of the coating film and suppress the occurrence of red rust in the defective portion.

By the way, in the defective portion of the coating film, the action of the sulfate ion generated by dissolving the metal sulfate is started at an early stage, so that the sulfate ion not only dissolves the metal but also exposes the steel material to the defective portion. Also acts directly, which may promote a certain amount of corrosion damage to the defective part. Therefore, it is not necessary to capture the metal ion generated as a cation by dissolving this sulfate in the defective portion of the coating film, but it is advantageous to capture a certain amount of the sulfate ion generated as an anion in the defective portion of the coating film. In some cases. Therefore, when the coating material and the coating film contain oxides and / or hydroxides of Ca, Sr, Ba, which are alkaline earth metals that form a sparingly soluble salt with sulfate ions, red rust of the defective portion is generated more. It may be possible to suppress it.

Further, when the paint and the coating film satisfy the above condition 1 or condition 2, the following actions are exhibited. When corrosion progresses in the defective part of the coating film, the corrosion of the steel material also progresses between the coating film and the steel material in the part adjacent to the defective part and in close contact with the coating film, and the width of the defective part of the coating film expands. Become. The degree of expansion of the width of the defective portion of the coating film depends on the adhesion of the coating film. When the ratio of metal to the total mass of powder and binder is high, the metal ions dissolved around the solid metal form corrosion products and the volume of the solid containing the solid metal expands to the binder. It tends to reduce the bondability of steel materials. When the ratio of the metal to the total mass of the powder and the binder is set to less than 70% by mass, which is lower than the lower limit of the amount of zinc in so-called zinc rich paint, which is 70% by mass, the adhesion of the coating film around the defective portion of the coating film is set. The deterioration of the property is suppressed, and the expansion and progress of the defective portion of the coating film can be suppressed. When the mass ratio of the zinc-based metal is less than 40% by mass, it is necessary that B / A ≤ 0.3 from the viewpoint of ensuring the anticorrosion effect of the zinc-based metal, but the zinc-based metal When the mass ratio of is 40% by mass or more, B / A ≦ 0.4 or less may be sufficient.

(Second Embodiment)
The coating material according to the second embodiment is a coating material containing a powder and a binder.

(powder)
The powder contains nickel sulfate and at least one metal selected from the group consisting of zinc and zinc alloys (alloy powders containing aluminum, magnesium, etc. in addition to zinc).

(Nickel sulfate)
The amount of nickel sulfate dissolved in 100 g of water is 0.5 g or more at 5 ° C.
The mass ratio of the nickel sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%. The lower limit may be 0.5% by mass, 1% by mass, 2% by mass, 3% by mass, or 4% by mass. The upper limit may be 50% by mass, 40% by mass, 30% by mass, 20% by mass, and 15% by mass.

(metal)
The metal is at least one metal selected from the group consisting of zinc and zinc alloys, and may contain a plurality of types. Examples of zinc alloys are zinc aluminum alloys and zinc magnesium alloys.

The mass ratio of at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%, may be 10 to 75 mass%, and is 35 to 65 mass%. There may be. The lower limit may be 5% by mass, 10% by mass, 20% by mass, 30% by mass, or 35% by mass. The upper limit may be 90% by mass, 85% by mass, 80% by mass, 75% by mass, 70% by mass, and 65% by mass.

(Other components in powder)
The powder can contain components other than nickel sulfate and the above-mentioned metals, if necessary.
Examples of other components are metal sulfates other than nickel sulfate, pigments, and oxides or hydroxides of alkaline earth metals.

Examples of metal sulfates other than nickel sulfate are selected from the group consisting of aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. It is at least one kind, and may include a plurality of kinds. Each of the above-mentioned metal sulfates has sufficient solubility in water like nickel sulfate, that is, the amount dissolved in 100 g of water is 0.5 g or more at 5 ° C.

Examples of pigments are color pigments, extender pigments, rust preventive pigments, and special functional pigments.

The mass ratio of the other metal sulfate to the total mass of the powder and the binder may be 0.10 to 60.0% by mass, 1.0 to 45.0% by mass, and 10. It may be 0 to 45.0% by mass.

The mass ratio of the pigment to the total mass of the powder and the binder may be 0.10 to 80.0% by mass, 1.0 to 70.0% by mass, and 10.0 to 45. It may be 0% by mass.

The powder may also contain phosphoric acid. The mass ratio of phosphoric acid to the total mass of the powder and the binder may be 10.0% by mass or less, 0.3 to 10.0% by mass, or 0.6 to 10.0% by mass. It may be 1.0 to 10.0% by mass.

However, the powder (painting) of the second embodiment does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.

(Aspect of powder)
The powder is usually a mixture of nickel sulfate powder, metal powder, and powder of additional components added as needed (eg, metal sulfate powder and pigment powder). However, some or all of the powder may be particles containing a plurality of constituents. For example, one particle may contain both nickel sulphate and metal.

The average particle size of the powder can be 1-40 μm and may be 5-20 μm.

(Binder)
The binder according to the present embodiment binds powders to each other and a base material such as a powder and a steel material. An example of a binder is a resin. The resin is not particularly limited, and is not particularly limited, and is vinyl butyral resin (polyvinyl butyral resin, etc.), epoxy resin, modified epoxy resin, acrylic resin, urethane resin, nitrocellulose resin, vinyl resin (polyvinyl chloride, polyvinyl acetate, and polyvinyl alcohol). Etc.), phthalic acid resin, melamine resin, fluororesin and the like. These resins may be thermoplastic resins or thermosetting resins. When the resin is a thermosetting resin, the coating material can further contain a curing agent if necessary, and the coating material usually cures during and after drying. The weight average molecular weight of the thermosetting resin is not particularly limited, but is about 200 to 20000. The weight average molecular weight of the thermoplastic resin is not particularly limited, but is about 1000 to 500000.

In the paint, the resin can form a continuous phase in which the powder is dispersed, with a solvent added as needed.

(Mixing ratio of powder and binder)
When the mass of the powder in the paint is A and the mass of the binder is B, the paint of the present embodiment can satisfy B / A ≤ 0.5 in order to uniformly exert the rust preventive effect, and B. / A≤0.4 may be satisfied, and B / A≤0.3 may be satisfied.

From the viewpoint of adhesion, the lower limit of B / A may be 0.01, 0.02, 0.05, 0.08, and 0.10. If the B / A is too small, the adhesion between the film and the steel material and the continuity of the film may be poor.

(solvent)
The paint according to this embodiment may further contain a solvent. Examples of the solvent include aromatic solvents such as xylene and toluene, alcohols having 3 or more carbon atoms such as isopropyl alcohol and normal butanol, and non-aqueous solvents such as ester solvents such as ethyl acetate; water, methyl alcohol and ethyl alcohol. Such as water-based solvents can be mentioned. Further, the resin may be a resin that dissolves in the solvent, may be a resin that dissolves in a non-aqueous solvent, or may be a resin that dissolves in an aqueous solvent.

In the present specification, the viscosity of the coating material is measured by a B-type viscometer at 20 ° C. The viscosity of the coating material is appropriately selected depending on the coating method, and can be, for example, 200 to 1000 cps. The content of the solvent in the coating material can be adjusted so that the viscosity of the coating material is within the above range.

(Ingredients other than powder, binder, and solvent)
The paint can further include additives such as thixotropic agents, dispersants, coupling agents, and antioxidants. The mass ratio of the additive may be 10.0% by mass or less with respect to the total mass of the powder and the binder.

(Action)
When the coated steel material is exposed to a corrosive environment in the state where powder containing both nickel sulfate and metal is present in the coating film, nickel sulfate dissolves in water and dissociates into nickel ions and sulfate ions. Sulfate ions dissolve zinc-based metals to generate zinc ions (including Al and Mg ions in the case of zinc alloys). In addition, steel materials placed in a corrosive environment are dissolved by a corrosive reaction to generate iron ions. The corrosion reaction of the steel material tends to be suppressed by the sacrificial anticorrosive action of the metal in the coating film, but nickel sulfate assists the progress of the corrosion reaction of the steel material.

A thin iron rust layer mainly composed of iron ions is formed along with the corrosion reaction of steel materials by the sacrificial anticorrosive action and the assistance of the corrosion reaction by nickel sulfate, but nickel ions are taken into the iron rust layer to make the rust layer anticorrosive. At the same time, zinc ions (including Al and Mg ions in the case of zinc alloy powder) and sulfate ions are also incorporated into the rust layer, and the obtained iron rust layer functions as an anticorrosion rust layer. The iron rust layer containing nickel ions has particularly high corrosion resistance as compared with the case where it contains metal cations contained in other sulfates.

Further, when a metal sulfate other than nickel sulfate is added together with nickel sulfate, the metal ions eluted from them also work to enhance the corrosion resistance of the anticorrosion rust layer.

Further, even when the residual rust layer already exists on the surface of the steel material, the residual rust layer is changed to the anticorrosion rust layer by the effect of the above ions.

Furthermore, since the coating film does not contain hydroxides or oxides of alkaline earth metals such as calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide, the dissociated alkaline earth metal The reaction of ions with sulfate ions to form a sparingly soluble salt at an early stage is inhibited, and the action of the present invention is less likely to be hindered.

(Third Embodiment)
The coating material according to the third embodiment is a coating material containing a powder and a binder.

(powder)
The powder is at least one selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. Seed metal sulphate and
Includes at least one metal selected from the group consisting of zinc and zinc alloys.

(Metal sulfate)
The metal sulfate is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. It is one kind, and may include any plurality of kinds among these. Each of the above-mentioned metal sulfates has sufficient solubility in water, that is, the amount dissolved in 100 g of water is 0.5 g or more at 5 ° C. It should be noted that calcium sulfate and the like have almost no effect because of their low solubility in water.

The metal sulfate preferably contains at least one selected from the group consisting of nickel sulfate, aluminum sulfate, and magnesium sulfate.

The ratio of at least one kind of metal sulfate is 0.07 mol or more with respect to 100 g of at least one kind of metal. The upper limit of the proportion of at least one metal sulfate may be 0.5 mol.

The mass ratio of at least one metal sulfate to the total mass of the powder and the binder can be 0.1 to 60.0 mass%. The lower limit may be 0.5% by mass, 1% by mass, 2% by mass, 3% by mass, or 4% by mass. The upper limit may be 50% by mass, 40% by mass, 30% by mass, 20% by mass, and 15% by mass.

(metal)
The metal is at least one metal selected from the group consisting of zinc and zinc alloys, and may contain a plurality of types. Examples of zinc alloys are zinc aluminum alloys and zinc magnesium alloys.

The mass ratio of at least one metal to the total mass of the powder and the binder can be 1.0 to 95.0 mass% and may be 1.0 to 85.0 mass%. .. The lower limit may be 3% by mass, 5% by mass, 10% by mass, 20% by mass, 30% by mass, and 35% by mass. The upper limit may be 90% by mass, 85% by mass, 80% by mass, 75% by mass, 70% by mass, and 65% by mass.

(Other components in powder)
The powder may contain components other than the above-mentioned metal sulfate and metal, if necessary.
An example of another component is a pigment.

Examples of pigments are color pigments, extender pigments, rust preventive pigments, and special functional pigments.

The mass ratio of the pigment to the total mass of the powder and the binder may be 0.10 to 80.0% by mass, 1.0 to 70.0% by mass, and 10.0 to 45. It may be 0% by mass.

The powder may also contain phosphoric acid. The mass ratio of phosphoric acid to the total mass of the powder and the binder may be 10.0% by mass or less, 0.3 to 10.0% by mass, or 0.6 to 10.0% by mass. It may be 1.0 to 10.0% by mass.

However, the powder (painting) of the third embodiment does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.

(Powder form)
The powder is usually a mixture of metal sulfate powder, metal powder, and powder of additional components (eg, pigment powder) added as needed. However, some or all of the powder may be particles containing a plurality of constituents. For example, one particle may contain both a metal sulfate and a metal.
The average particle size of the powder can be 1-40 μm and may be 5-20 μm.

(Binder)
The binder according to the present embodiment binds powders to each other and a base material such as a powder and a steel material. In paints, powder in the binder is an example of a binder, which is a resin. The resin is not particularly limited, and is not particularly limited, and is vinyl butyral resin (polyvinyl butyral resin, etc.), epoxy resin, modified epoxy resin, acrylic resin, urethane resin, nitrocellulose resin, vinyl resin (polyvinyl chloride, polyvinyl acetate, and polyvinyl alcohol). Etc.), phthalic acid resin, melamine resin, fluororesin and the like. These resins may be thermoplastic resins or thermosetting resins. When the resin is a thermosetting resin, the coating material can further contain a curing agent if necessary, and the coating material usually cures during and after drying. The weight average molecular weight of the thermosetting resin is not particularly limited, but is about 200 to 20000. The weight average molecular weight of the thermoplastic resin is not particularly limited, but is about 1000 to 500000.

In the paint, the resin can form a continuous phase in which the powder is dispersed, with a solvent added as needed.

(Mixing ratio of powder and binder)
When the mass of the powder in the paint is A and the mass of the binder is B, the paint of the present embodiment can satisfy B / A ≤ 0.5 in order to uniformly exert the rust preventive effect, and B. / A≤0.4 may be satisfied, and B / A≤0.3 may be satisfied.
From the viewpoint of adhesion, the lower limit of B / A may be 0.01, 0.02, 0.05, 0.08, and 0.10. If the B / A is too small, the adhesion between the film and the steel material and the continuity of the film may be poor.

(solvent)
The paint according to this embodiment may further contain a solvent. Examples of the solvent include aromatic solvents such as xylene and toluene, alcohols having 3 or more carbon atoms such as isopropyl alcohol and normal butanol, and non-aqueous solvents such as ester solvents such as ethyl acetate; water, methyl alcohol and ethyl alcohol. Such as water-based solvents can be mentioned. Further, the resin may be a resin that dissolves in the solvent, may be a resin that dissolves in a non-aqueous solvent, or may be a resin that dissolves in an aqueous solvent.

In the present specification, the viscosity of the coating material is measured by a B-type viscometer at 20 ° C. The viscosity of the coating material is appropriately selected depending on the coating method, and can be, for example, 200 to 1000 cps. The content of the solvent in the coating material can be adjusted so that the viscosity of the coating material is within the above range.

(Ingredients other than powder, binder, and solvent)
The paint can further include additives such as thixotropic agents, dispersants, coupling agents, and antioxidants. The mass ratio of the additive may be 10.0% by mass or less with respect to the total mass of the powder and the binder.

(Action)
When the coated steel material is exposed to a corrosive environment in a state where the metal sulfate and the powder containing the metal coexist in the coating film, the metal sulfate dissolves in water and dissociates into metal ions and sulfate ions. Sulfate ions dissolve zinc-based metals in powder to generate zinc ions (including Al and Mg ions in the case of zinc alloys). In addition, steel materials placed in a corrosive environment are dissolved by a corrosive reaction to generate iron ions. The corrosion reaction of the steel material tends to be suppressed by the sacrificial anticorrosive action of the zinc-based metal, but the presence of the metal sulfate assists the progress of the corrosion reaction of the steel material.

A thin iron rust layer mainly composed of iron ions is formed along with the corrosion reaction of steel materials by the sacrificial anticorrosion action and the assistance of the corrosion reaction by metal sulfate. At the same time, zinc ions (including Al and Mg ions in the case of alloy powder) and sulfate ions are also incorporated into the rust layer, and this rust layer functions as an anticorrosion rust layer. When the residual rust layer already exists on the surface of the steel material, the residual rust layer is also changed to the anticorrosion rust layer by the effect of the above ions.

When 0.07 mol or more of metal sulfate is added to 100 g of metal, the amount of metal sulfate added is sufficiently large with respect to the metal powder. Therefore, the metal sulfate not only dissolves the metal but also iron in the steel material. Also promotes dissolution of. Therefore, since a large amount of iron ions constituting the anticorrosion rust layer is supplied, the anticorrosion rust layer can be further strengthened.

Further, when the B / A is set to the above lower limit or more, the ratio of the resin becomes more than a certain level, so that the adhesion of the coating film to the steel material is improved and the invasion of the coating film in a corrosive environment such as water and salt also occurs. Since it becomes gentle, the anticorrosion effect on the steel material is further enhanced.

(Fourth Embodiment)
[Coated steel material and corrosion-resistant steel structure based on the paint according to the first to third embodiments]
1 (a) is a cross-sectional view of a steel material according to an embodiment of the present invention, FIG. 1 (b) is a cross-sectional view of a coated steel material according to an embodiment of the present invention, and FIG. 1 (c) is the present invention. The cross-sectional view of the corrosion-resistant steel structure which concerns on one Embodiment is shown.

The steel type of the steel material 10 is not particularly limited, and may be an ordinary steel material, a low alloy steel material, a high alloy steel material such as stainless steel, or a special steel material. The steel material does not have to have a rust layer or an organic layer or an inorganic layer on the surface, and may have a rust layer or an organic layer or an inorganic layer.

Before applying the paint, the surface of the steel material 10 may be polished by shot blasting or an electric tool, and if a rust layer is formed on the surface, rust that can be easily removed by a wire brush or the like may be removed. good. Further, when the steel material has a rust layer or an organic layer or an inorganic layer on the surface, it is not necessary to peel off these layers, and a coating film can be provided on the surface of the steel material including these layers.

The coated steel material 100 of FIG. 1 (b) is obtained by applying the paint of any of the first to third embodiments described above on the surface of the steel material 10 of FIG. 1 (a) and drying or curing the paint. Can be obtained by Therefore, the coating film 20 contains the above-mentioned powder, binder and the like, and the composition of these powders and the binder and the like is the same as that of any of the paints in the above-mentioned first to third embodiments. Can be done.

In the coating film 20, the resin as a binder can form a continuous phase in which powder is dispersed.

Examples of the method for applying the paint include air spray, airless spray, brush coating, roller coating and the like. Further, the coating material is dried, for example, by natural drying in air at room temperature (25 ° C.) and atmospheric pressure (1 atm). The drying time varies depending on the drying form, but is usually about 30 minutes to 6 hours, and is selected to such an extent that a practical coating film strength can be obtained. The coating film 20 can be formed by applying the coating film once, but may also be formed by applying the coating film 20 times in layers. When the coating film 20 is formed by applying the coating film a plurality of times, the composition of the coating film may be the same or different.

The thickness of the coating film 20 can be 1 to 1000 μm. Further, when the thickness of the coating film 20 is 10 μm or more, each component in the paint is sufficiently retained on the steel material, and when the coated steel material is exposed to a corrosive environment, the anticorrosive compound layer 30 is formed. Only steel corrosion tends not to precede too much. Further, when the thickness of the coating film is 500 μm or less, it is not only economically advantageous, but also when a bending moment is generated in the coating film due to stress generated by some influence on the underlying steel material, the coating film is applied. It is possible to suppress cracking of the film 20 or peeling from the surface of the steel material. The lower limit of the thickness of the coating film 20 may be 3 μm, 5 μm, or 10 μm. The upper limit of the thickness of the coating film 20 may be 750 μm, 500 μm, or 300 μm.

Coating 20, in a dry film thickness of 100 [mu] m, preferably has a 300g ^/ (m 2 · 24h) following moisture permeability, and more preferably has a 200g ^/ (m 2 · 24h) or less moisture permeability. Coating 20, by having a 300g / (m 2 · ^24h) following moisture permeability, in a corrosive environment, by suppressing the acceleration of the dissociation of such metals and metal sulfates, suppresses efflux to these external be able to. As a result, the metal and the metal sulfate in the coating film 20 are likely to be effectively applied to the formation of the anticorrosion compound layer 30.

If the moisture permeability of the coating film 20 is too low, the reaction (dissociation, etc.) of the metal and the metal sulfate is slowed down, but this itself is not a problem from the viewpoint of ensuring corrosion resistance in a severe corrosive environment. This is because if the moisture permeability of the coating film is not zero, water or the like invades, albeit slightly, and the formation of the anticorrosive compound layer accompanied by corrosion proceeds. Therefore, even if the moisture permeability of the coating film 20 is low, the effect of the present invention can be obtained if it is not zero. For example, the moisture permeability of the coating film 20 may be a 3g ^/ (m 2 · 24h) or more, may be 5g ^/ (m 2 · 24h) or more. Even if the initial moisture permeability is zero, when the coating film is used as an anticorrosion coating film, the coating film begins to deteriorate due to deformation caused by ultraviolet rays and stress acting on the steel material, and the moisture permeability increases with time. Due to the increase, constant moisture permeability is obtained during use.

Further, after forming the coating film 20, another one layer or two or more layers of topcoat coating film may be formed on the surface of the coating film 20. That is, the coated steel material 100 may further include a topcoat coating film provided on the coating film 20.

Topcoat coating film, the dry film thickness 100 [mu] m, it is preferably a layer having a 300g ^/ (m 2 · 24h) or less moisture permeability. Topcoat coating film, the dry film thickness 100 [mu] m, and more preferably has a 200g ^/ (m 2 · 24h) or less moisture permeability.

Moisture permeability refers to the amount of water vapor that passes through a unit area of film-like substance in a certain period of time. With the film-like substance as the boundary line, one air is kept at 90% relative humidity and the other air is kept dry by a dehumidifying agent. , The amount of water vapor passing through this boundary line in 24 hours is a value converted per ^{1 m 2 of the film-like substance.} By forming the topcoat coating film as described above, it is possible to impart designability to the steel material and the like, and it is possible to assist the anticorrosion effect of the anticorrosion compound layer, and it is possible to further improve the corrosion resistance of the steel material. It becomes. Further, the moisture permeability of the top coating film, in a dry film thickness of 100 [mu] m, may be 10g ^/ (m 2 · 24h) or more. By moisture permeability of the topcoat paint film is 10g / (m 2 · ^24h) or more, the water required for the formation of anti-corrosion compound layer easily supply early between the steel 10 and the coating film 20, the corrosion resistance imparted The effect of is easy to be exhibited. With such a topcoat coating film, the amount of water supplied to the coating film 20 can be controlled regardless of the external environment. However, the moisture permeability of the top coating film, in a dry film thickness of 100 [mu] m, no problem even less than ^{10g / (m 2 · 24h)} . When the moisture permeability of the topcoat coating film is small, the supply of water between the steel material 10 and the coating film 20 is reduced, and it becomes difficult for the anticorrosion compound layer to be formed at an early stage. However, at the same time, it is possible to prevent early corrosion, elution and decrease in plate thickness of the steel material 10 due to moisture permeation. This is because when the corrosion of the steel material 10 is sufficiently prevented by the topcoat coating film, the anticorrosion compound layer does not necessarily have to be formed at an early stage.

The resin coating material of the top coat may be a polyethylene resin, an epoxy resin, a polyvinyl butyral resin, a polyvinyl alcohol resin, or a mixture thereof. The moisture permeability of the topcoat coating film can be controlled within a desired range by selecting or mixing the resin used for the resin coating film. For example, moisture permeability in the dry film thickness 100μm polyethylene resin was about ^{5~20g / (m 2 · 24h)} , moisture permeability of the epoxy resin is about ^{5~40g / (m 2 · 24h)} , polyvinyl butyral resin the moisture permeability was about ^{100~200g / (m 2 · 24h)} , moisture permeability of the polyvinyl alcohol resin is about ^{200~400g / (m 2 · 24h)} .

The thickness of the topcoat coating film is, for example, 10 to 300 μm, preferably 25 to 200 μm, and more preferably 25 to 150 μm. Further, in order to obtain the effect of the topcoat coating film, the thickness of the topcoat coating film is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, and particularly preferably 20 μm or more. It may be 30 μm or more, or 50 μm or more. The thickness of the topcoat coating film can be, for example, 1 mm or less, 500 μm or less, 300 μm or less, or the like from an economical point of view, but is not particularly limited from the viewpoint of obtaining the effect of the topcoat film. It is also possible to apply two or more layers of different types of topcoat coatings.

As shown in FIG. 1 (c), the corrosion-resistant steel structure 200 includes a steel material 10, a coating film 20, and an anticorrosion compound layer 30 formed between the steel material 10 and the coating film. By exposing the coated steel material 100 shown in FIG. 1 (b) to a corrosive environment containing water, each component in the coating film 20 and a metal component such as iron in the steel material 10 have the above-mentioned actions. Corrosion-resistant steel structure is formed by forming an anticorrosion compound layer 30 containing an oxide containing iron ions as a main component, metal ions and sulfate ions derived from a metal sulfate, and zinc ions derived from a zinc-based metal. Body 200 is obtained.

For the formation of the anticorrosion compound layer 30, the suitable exposure environment of the coated steel material 100 can be a water-containing atmosphere capable of providing water to the coated steel material 100, and the above exposure is, for example, in an outdoor environment or an indoor environment, such as hydrochloric acid. It may be carried out in an acidic environment, a sea salt particle flying environment, or an air pollutant flying environment such as _{SO x} or NO _x. Further, as a suitable exposure condition for the coated steel material 100, for example, exposure to the outdoors for about 1 to 30 days can be mentioned.

Since the corrosion-resistant steel structure 200 includes the anticorrosive compound layer 30, it is possible to prevent water, oxygen and various corrosive substances existing in the external corrosive environment from being excessively permeated into the steel material (barrier effect). It has excellent corrosion resistance not only in a general corrosive environment but also in an acidic environment or a severe corrosive environment containing chloride. The coating film 20 may be peeled off after the anticorrosion compound layer 30 is formed.

The thickness of the anticorrosion compound layer 30 may be about 0.5 to 50 μm. When the thickness of the anticorrosion compound layer 30 is 0.5 μm or more, the corrosion resistance effect of the steel material can be easily obtained.

This anticorrosive compound layer exerts its effect not only in a general corrosive environment but also in an acidic environment or a severe corrosive environment containing chloride. The acidic environment or severe corrosive environment containing chloride is defined as a low pH environment (for example, pH 4.0 or less) or a natural air corrosive environment (general corrosive environment) in which chloride is constantly present on the surface of various steel materials. ) Is present (for example, on the ground where seawater in the immediate vicinity of the sea directly flies), and an environment where corrosion of steel materials is expected to be significantly accelerated is exemplified.

Further, as shown in FIGS. 2A to 2C, a plated steel material 14 may be used instead of the steel material 10. As shown in FIG. 2A, the plated steel material 14 has a plating layer 12 made of a metal having an anticorrosion effect, for example, aluminum, zinc, or a metal such as an alloy thereof, on the surface of the steel material 10. When the plated steel material 14 is used instead of the steel material 10, as shown in FIG. 2B, the coated steel material 100 includes the plated steel material 14 and the coating film 20 formed on the surface of the plated steel material 14. .. Examples of the plated steel material 14 include hot-dip galvanized steel material.

When the plated steel material 14 is used instead of the steel material 10, as shown in FIG. 2C, the corrosion-resistant steel structure 200 includes the plated steel material 14, the coating film 20, the plated steel material 14, and the coating film 20. It is provided with an anticorrosion compound layer 30 formed between the coating film 20 and the coating film 20. When the above paint is applied onto the steel material 10 as shown in FIG. 1, the formation of iron ions and iron oxides due to the corrosion of a part of iron or the like in the steel material 10 contributes to the formation of the anticorrosion compound layer 30. When the paint is applied onto the plated steel material 14 as shown in FIG. 2, the formation of zinc ions and zinc oxide due to the corrosion of a part of iron or the like in the plating layer 12 contributes to the formation of the anticorrosion compound layer 30.

(Deformation mode when having a specific topcoat film)
In the case where coating steel has a top coating film having a 300g / (m 2 · ^24h) following moisture permeability in a dry film thickness of 100 [mu] m, based on the coating material other than the first to third embodiments is formed The high corrosion resistance of the present invention can be realized even with the coated film.
For example, in the coating film based on the coating film of the third embodiment, the ratio of at least one kind of metal sulfate in the coating film is 0.07 mol or more with respect to 100 g of at least one kind of metal in the coating film, but the third. Based on the composition of the coating film of the embodiment, the proportion of at least one metal sulfate in the coating film may be less than 0.07 mol. Even in such a case, it is possible to have the corrosion resistance as in the third embodiment. The lower limit of the ratio of at least one metal sulfate can be 0.005 mol. In addition, the coating may also contain oxides and / or hydroxides of alkaline earth metals such as calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.

Hereinafter, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited to these examples, and various types are described without departing from the technical idea of the present invention. Can be changed.

(First Embodiment: Test Nos. A1 to A29)
<Manufacturing of coated steel>
Steel materials having dimensions of 70 × 150 × 3 mm and having the compositions shown in Table 1 below were prepared. This steel material was exposed to the atmosphere (Obama City) for 3 years to naturally form a rust layer on the surface, and then the surface was cleaned with a wire brush to obtain a steel material.

<Preparation of paint>
Zinc powder, aluminum sulfate powder, nickel sulfate powder, magnesium sulfate powder, calcium sulfate powder, calcium oxide powder, barium oxide powder, and extender pigment powder were prepared. The average particle size of each powder was about 10 μm. Each powder, epoxy resin (Mitsubishi Chemical, Epicoat: epoxy equivalent 160 to 170), and solvent were mixed and dispersed in a bead mill to obtain paints of test numbers A1 to A26. As the solvent, a mixture of xylene in an amount and ratio such that the viscosity of the coating material was 200 to 1000 cps at 20 ° C. and ethylene glycol monotersial butyl ether was used. Tables 2 to 4 show the mass ratio of the solid content, that is, the powder and the epoxy resin in the coating material. Barium sulfate was used as the extender pigment.

<Paint application>
Each paint was applied to the surface of the steel material by the air spray method. Then, the coated steel material was dried in air for 7 days at room temperature (25 ° C.) according to a normal coating film test method to obtain a coated steel material having each test number. The thickness (dry film thickness) of the coating film formed from the paint is shown in the table. Further, the ratio (B / A) of the mass B of the binder to the mass A of the powder is also shown in the table.

In Test Number A4 and A17, after the formation of the coating film, further, the epoxy resin was applied and dried as top coating film, the moisture permeability of 100μm was formed film (thickness 20 [mu] m) of 5g ^/ (m 2 · 24h) ..

The moisture permeability was measured in advance by preparing a topcoat film having a thickness of 100 μm with the same epoxy resin and measuring in accordance with Condition B (temperature 40 ° C., relative humidity 90%) of JIS Z 0208 (cup method). ..

<Corrosion resistance test>
Using a cutter, two cuts with a length of 80 mm and a width of 0.1 mm and a depth reaching the steel material are cut on the main surface of a 70 x 150 x 3 mm coated steel material at 60 ° at the center of the main surface. I gave it like this.

The coated steel material was maintained in a corrosive environment for 240 cycles by adopting the cycle D method (CCT) of the cycle corrosion test method specified in JIS K5600-7-9: 2006. This corrosion test consists of (1) spraying a 50 ± 10 g / L sodium chloride aqueous solution for 30 minutes in an environment of 30 ± 2 ° C., and (2) a wet environment with a temperature of 30 ± 2 ° C. and a humidity of 95 ± 3% RH. This is a cycle corrosion test method in which a total of three steps of wetting for 1.5 hours and (3) drying at temperatures of 50 ± 2 ° C. and 30 ± 2 ° C. for 2 hours, respectively, is one cycle.

<Corrosion resistance evaluation>
After the corrosion test, the state of red rust generated in this cut portion was confirmed and classified into the following four ranks. A is "no red rust is generated in the cut part", B is "partially dotted red rust is generated in the cut part", C is "partial red rust is generated in the cut part", and D is "red rust is generated in the entire cut part length". Outflow ".

Further, the average swelling width in the cut portion was measured and classified into the following three ranks. When S has an average bulge width of less than 0.1 mm, A has an average bulge width of 0.1 mm or more and less than 1 mm, and B has an average bulge width of 1 to 1.5 mm, the average bulge width exceeds 1.5 mm. Was designated as C. As for the swelling width, 12 points of swelling width on one side were measured at intervals of 10 mm along the cut, and the average value of the top 10 points was used.

The test results are shown in Tables 2 to 4.

The following was clarified from the test results. In test numbers A1 to A11, which contain metal sulfate and zinc powder and have a B / A of 0.5 or less, and test numbers A14, A15, A18 to A20, and A22 to A29, test numbers A12, A13, Compared with A16, A17, and A21, the occurrence of red rust in the cut portion was suppressed.

Further, Condition 1: That is, the mass ratio of the metal to the total mass of the powder and the binder is 40% by mass or more and less than 70% by mass, and B / A ≤ 0.4 is satisfied, or Condition 2: Test numbers A3, A4, A6 to A9, A15, A19 in which the mass ratio of at least one metal to the total mass of the powder and the binder is less than 70% by mass and B / A ≤ 0.3 is satisfied. , A22, and A26 to A29, the average swelling width of the cut portion was suppressed to be small.
In test number A27 satisfying B / A ≦ 0.2, the average swelling width of the cut portion was extremely small, and the swelling was not measured with the measurement accuracy of the minimum width of 0.1 mm. Therefore, under condition 2, B / It was confirmed that there is a particular effect when A ≦ 0.2.

(Second and third embodiments: test numbers B1 to B39)
<Manufacturing of coated steel>
A steel material was obtained in the same manner as in Test No. A1.

<Preparation of paint>
Zinc powder, aluminum sulfate powder, nickel sulfate powder, magnesium sulfate powder, sodium sulfate powder, and extender pigment powder were prepared. The average particle size of each powder was about 10 μm. Each powder, epoxy resin (Mitsubishi Chemical, Epicoat: epoxy equivalent 160 to 170), and solvent were mixed and dispersed in a bead mill to obtain paints of test numbers B1 to B39. As the solvent, a mixture of xylene and ethylene glycol monotersial butyl ether having an amount and ratio such that the viscosity of the coating material was 200 to 1000 cps at 20 ° C. was used. Tables 4 to 6 show the mass ratio of the solid content, that is, the powder and the epoxy resin in the coating material. Barium sulfate was used as the extender pigment.

<Paint application>
Each paint was applied to the surface of the steel material by an air spray method, and a coated steel material of each test number was obtained in the same manner as in test number A1. The thickness (dry film thickness) of the coating film formed from the paint is shown in Tables 3 to 5. Further, the ratio (B / A) of the mass B of the binder to the mass A of the powder is also shown in the table.

Test No. B3, B8, B16, B21, the B28, B30, and B34, after the formation of the coating film, further, the epoxy resin was applied and dried as top coating film, the moisture permeability of 100μm is 5g / ^{(m 2} · A film (thickness 20 μm) of 24 hours) was formed. The measurement of moisture permeability was carried out in the same manner as in Test No. A4.

<Corrosion resistance test>
An aqueous solution containing 0.5 mass% NaCl and 0.075% NaHCO _{3 was prepared.} The following three steps were set as one cycle for the coated steel material, and this was repeated 45 times (45 days).
(1) The coated steel material is allowed to stand horizontally for 6 hours in an environment having a temperature of 50 ° C. and a relative humidity of 95%.
(2) Immerse the coated steel material in a test aqueous solution at 25 ° C. for 15 minutes.
(3) The coated steel material is allowed to stand horizontally for 17 hours and 45 minutes in an environment having a temperature of 60 ° C. and a relative humidity of 50%.

<Corrosion resistance evaluation>
The corrosion current density of the coated steel material after the corrosion test was measured in the test aqueous solution.
Specifically, the polarization test is performed by a three-electrode method in which the coated steel material after the corrosion test is used as the working electrode and the Ag / AgCl electrode and the Pt plate are used as the reference electrode and the counter electrode, respectively, and the Tafel method is used from the anodic polarization curve and the cathode polarization curve. The corrosion current density was determined by Before the polarization test, the side surface and the back surface of the test piece were thickly coated with anticorrosive paint and excluded from the evaluation.

The composition and test results are shown in Tables 5 to 7.

The following was clarified from the test results.
The mass ratio of nickel sulfate to the total mass of the powder and the binder, which contains nickel sulfate and a zinc-based metal, is 0.1 to 60.0 mass%, and is based on the total mass of the powder and the binder. , The mass ratio of zinc light metal is 1.0 to 95.0% by mass, and it does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide. Numbers B1 to B3, B6 to B8, B11, B14 to B16, B19 to B21, B24, and nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, It contains at least one metal sulfate sulfate selected from the group consisting of zirconium sulfate, vanadium sulfate, and manganese sulfate, and a zinc-based metal, and the ratio of at least one metal sulfate is to 100 g of the zinc-based metal. In test numbers B14 to B26, which are 0.07 mol or more and do not contain calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, or barium hydroxide, test numbers B4, B5, B9, B10 , B12, B13, and B27 to B39, the corrosion current density was sufficiently small.
It was also found that the formation of the topcoat film also improved the corrosion resistance.

10 ... Steel material, 12 ... Plating layer, 14 ... Plated steel material, 20 ... Coating film, 30 ... Anticorrosion compound layer, 100 ... Coated steel material, 200 ... Corrosion resistant steel structure.

Claims (13)

A paint containing a powder and a binder,
The powder is
At least one metal sulfuric acid selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. With salt
Containing with at least one metal selected from the group consisting of zinc and zinc alloys,
The mass ratio of the at least one metal sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
A paint that satisfies B / A ≤ 0.5, where A is the mass of the powder in the paint and B is the mass of the binder. The coating material according to claim 1, further satisfying either the following condition 1 or condition 2.
Condition 1: The mass ratio of the at least one metal to the total mass of the powder and the binder is 40% by mass or more and less than 70% by mass, and B / A ≦ 0.4 is satisfied.
Condition 2: The mass ratio of the at least one metal to the total mass of the powder and the binder is less than 70% by mass, and B / A ≦ 0.3 is satisfied. The coating material according to claim 1 or 2, wherein the powder further contains an oxide of an alkaline earth metal and / or a hydroxide. A paint containing a powder and a binder,
The powder is
Nickel sulfate and
Contains at least one metal selected from the group consisting of zinc and zinc alloys
The mass ratio of the nickel sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
The powder is a paint that does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide. A paint containing a powder and a binder,
The powder is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. One kind of metal sulfate and
Containing with at least one metal selected from the group consisting of zinc and zinc alloys,
The ratio of the at least one kind of metal sulfate is 0.07 mol or more with respect to 100 g of the at least one kind of metal.
The powder is a paint that does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide. A steel material and a coating film formed on the surface of the steel material are provided.
The coating film contains a powder and a binder, and contains
The powder is
At least one metal sulfuric acid selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. With salt
Containing with at least one metal selected from the group consisting of zinc and zinc alloys,
The mass ratio of the at least one metal sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
When the mass of the powder in the coating film is A and the mass of the binder is B, B / A ≦ 0.5 is satisfied.
A coated steel material having a coating film thickness of 10 to 300 μm. The coated steel material according to claim 6, further satisfying either the following condition 1 or condition 2.
Condition 1: The mass ratio of the at least one metal to the total mass of the powder and the binder is 40% by mass or more and less than 70% by mass, and B / A ≦ 0.4 is satisfied.
Condition 2: The mass ratio of the at least one metal to the total mass of the powder and the binder is less than 70% by mass, and B / A ≦ 0.3 is satisfied. The coated steel material according to claim 6 or 7, wherein the powder further contains an oxide of an alkaline earth metal and / or a hydroxide. A steel material and a coating film formed on the surface of the steel material are provided.
The coating film contains a powder and a binder and contains.
The powder is
Nickel sulfate and
Contains at least one metal selected from the group consisting of zinc and zinc alloys
The mass ratio of the nickel sulfate to the total mass of the powder and the binder is 0.1 to 60.0 mass%.
The mass ratio of the at least one metal to the total mass of the powder and the binder is 1.0 to 95.0 mass%.
The powder does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.
A coated steel material having a coating film thickness of 10 to 300 μm. A steel material and a coating film formed on the surface of the steel material are provided.
The coating film contains a powder and a binder, and contains
The powder is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. One kind of metal sulfate and
Containing with at least one metal selected from the group consisting of zinc and zinc alloys,
The ratio of the at least one kind of metal sulfate is 0.07 mol or more with respect to 100 g of the at least one kind of metal.
Contains neither calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide,
A coated steel material having a coating film thickness of 10 to 300 μm. Further provided with a topcoat coating film provided on the coating film,
The topcoat coating film, the dry film thickness 100 [mu] m, 300 g ^/ have a (m 2 · 24h) following moisture permeability, coating steel according to any one of claims 6-10. A steel material, a coating film formed on the surface of the steel material, and a topcoat coating film provided on the coating film are provided.
The coating film contains a powder and a binder and contains.
The powder is at least selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. One kind of metal sulfate and
Containing with at least one metal selected from the group consisting of zinc and zinc alloys,
The topcoat coating film, the dry film thickness 100 [mu] m, with a 300g ^/ (m 2 · 24h) following moisture permeability, coating steel. The coated steel material according to claim 12, wherein the powder does not contain any of calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, barium oxide, and barium hydroxide.

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