WO2011105529A1

WO2011105529A1 - Corrosion-proofing coating composition and process for production thereof, and method for prevention of corrosion in steel material

Info

Publication number: WO2011105529A1
Application number: PCT/JP2011/054237
Authority: WO
Inventors: 勉戸越; 慎二曽根; 幹友池田; 孝雄山本
Original assignee: 新日本製鐵株式会社; ダイキ工業株式会社; エス・エルテック株式会社
Priority date: 2010-02-26
Filing date: 2011-02-25
Publication date: 2011-09-01
Also published as: KR20120120350A; JPWO2011105529A1; CN102782055A; TW201139570A; HK1175491A1; KR101431358B1; JP5759898B2; TWI435920B; CN102782055B

Abstract

A corrosion-proofing composition comprising: a compound comprising a cement, an inorganic powdery material and a swelling material; a polymer emulsion selected from a styrene/butadiene copolymer emulsion and an acryl/styrene copolymer emulsion; and a nitrous acid salt.

Description

Anticorrosion coating composition, method for producing the same, and method for preventing corrosion of steel

The present invention relates to an anticorrosion coating composition used as an undercoat material on a steel surface, a method for producing the same, and a method for preventing corrosion of a steel material.
This application claims priority based on Japanese Patent Application No. 2010-042285 filed in Japan on February 26, 2010 and Japanese Patent Application No. 2010-042298 filed on February 26, 2010 in Japan, The contents are incorporated here.

Steel structures such as steel structures and steel bridges are premised on long-term use. For this reason, these steel structures have been conventionally surface-coated for the purpose of preventing corrosion and ensuring aesthetics. Usually, the coating consists of three layers: a base coat for the purpose of preventing rust, a top coat for the purpose of ensuring weather resistance and aesthetics, and an intermediate coat for improving the adhesion between the base coat and the top coat. Has been. The coating life is greatly influenced by the coating material and the use environment, but in a relatively severe environment, there are examples of 6 years for the modified epoxy paint and 10 years for the epoxy urethane paint. Accordingly, a plurality of repaints are required during the service period of the steel structure.

Here, the mechanism of rust generation will be described. When iron is exposed to rainwater or the like, the moisture adsorbed on the iron surface takes in electrons from the iron element and causes a chemical reaction with oxygen in the air to generate OH ⁻ . On the other hand, Fe ^{2+ from} which electrons have been taken dissolves in moisture and combines with the generated OH ⁻ to become Fe (OH) ₂ , which is oxidized to FeOOH, Fe ₂ O ₃ .nH ₂ O, Fe ₃ O _4. It changes to rust such as nH ₂ O.

As one of iron rust prevention methods, a method is known in which the surface of iron is kept alkaline and passivated. In general, it is said that a passivating layer of Fe ₂ O ₃ is formed in a pH range of 9 to 12.5, and iron becomes stable. As a technique for preventing rust by keeping the iron surface alkaline, for example, in Patent Document 1, a compound in which carbon fiber is added to a main material composed of a mixture of white cement and ultrafine silica, and cationic styrene butadiene copolymer An invention of a surface coating agent comprising a water-soluble curing agent composed of a mixture of a coalesced polymer and a cyclohexyl methacrylate copolymer is disclosed.

Further, Patent Document 2 discloses an invention of a pollution-free rust-proof coating composition obtained by blending slag, mica, and aluminum phosphomolybdate containing an alkali group generated during a scouring process with respect to a resin solid content. Yes.

On the other hand, as an anticorrosion coating technique different from the alkali anticorrosion coating, in Patent Document 3, a mortar formed by mixing a polymer cement, an aggregate, water, and a lithium nitrite solution is applied to a predetermined portion of a concrete structure through a mortar spray nozzle. The invention of the mortar spraying method characterized by spraying on the surface is disclosed. In this method, a passive film (Fe ₂ O ₃ ) is formed by the following reaction due to the action of nitrite ions (NO ₂ ⁻ ) of lithium nitrite (LiNO ₂ ) present in the mortar, and rust Occurrence is prevented.
Fe ²⁺ + 2OH ⁻ + 2NO ₂ ⁻ → 2NO + Fe ₂ O ₃ + H ₂ O

Further, in Patent Document 4, an anion adsorbent is contained in the base conditioning material, so that a nest generated at the interface between the rust layer and the steel material (an anion is generated by the corrosion cell formed on the steel surface due to the corrosion of the steel). An invention of a base material adjustment material for steel that positively removes the anions in the portion (electrochemically supplemented and concentrated in the part) is disclosed.

JP-A-5-155649 Japanese Patent Laid-Open No. 2002-80786 JP 2007-177567 A JP 2004-299979 A

However, the surface coating agent described in Patent Document 1 uses carbon fiber, which is a high-cost material. In addition, by increasing the coating thickness (700-800 μm), the effect of preventing cracking of the coating and the diffusion suppression effect of moisture and oxygen is increased and the life is extended. High cost.
The pollution-free rust-proof coating composition described in Patent Document 2 is said to be excellent in long-term rust-proof properties, but the passive film on the surface of a steel material formed by components such as slag containing an alkali group It is destroyed by a corrosive factor that enters from a flawed part caused by deterioration or external damage, rust progresses in a short time, and the lifetime is as short as about ten years.

On the other hand, in the invention described in Patent Document 3, when the passive film is damaged due to some external factor, the passive film is reconstructed by the action of nitrite ions. In this case, the rust inhibitor is eluted because nitrite is soluble. For this reason, there is a problem with long-term corrosion resistance. In the invention described in Patent Literature 4, an anion adsorbent such as a calcium / aluminum composite hydroxide that is not consumed by reaction with cement is contained in a cement-based ground preparation agent containing an aqueous epoxy resin as an admixture, and steel material Although the occurrence of corrosion is suppressed, long-term anticorrosion properties are not clarified.

The present invention has been made in view of such circumstances, and is intended to reduce the surface treatment compared to the prior art, properly contain nitrite used as a rust inhibitor, reduce the diffusion speed of nitrite, and prevent rust prevention of steel materials. It aims at providing the anticorrosion coating composition which can maintain an effect over a long period of time, its manufacturing method, and the anticorrosion method of steel materials.

An anticorrosive coating composition according to the present invention includes a compound containing cement, an inorganic powder material, and an expansion material, a polymer emulsion selected from a styrene / butadiene copolymer emulsion or an acrylic / styrene copolymer emulsion, Contains nitrite.
By setting it as the said structure, the workability and durability as a coating material are ensured. Moreover, since an alkaline coating film is formed on the steel material surface, the steel material surface is passivated and corrosion does not proceed. When the passive film (Fe ₂ O ₃ ) is damaged due to some external factor, nitrite ions (NO ₂ ⁻ ) cause a chemical reaction with Fe ²⁺ and OH ⁻ and passivated film (Fe ₂ O ₃ ). To rebuild. For this reason, the lifetime of a steel structure can be significantly extended compared with the past. In addition, a solid structure can be constructed by adjusting the mass ratio of the cement to the inorganic powder material to be 1.0 to 1.4. Thereby, the spreading | diffusion speed of nitrite falls and it can maintain the rust prevention effect of nitrite over a long period of time. As a result, the number of repaints during the service period of the steel structure is reduced, and the cost for repainting can be greatly reduced. On the other hand, when the mass ratio of the cement to the inorganic powder material is less than 1.0 or exceeds 1.4, the diffusion speed of nitrite cannot be reduced appropriately.

Styrene / butadiene copolymer and acrylic / styrene copolymer both have good adhesion to the substrate, have little dependence on temperature, and have excellent elasticity even at low temperatures and relatively high temperatures. . For this reason, the coating film excellent in water permeability and a weather resistance can be obtained.
The synthetic resin of the cationic styrene butadiene copolymer system described in Patent Document 1 can be expected to have a rust prevention effect, but the deformation ability (elongation) of the coating film is 0.4%, and the bending axial force is applied to the steel material. If the elongation at the time of acting is 0.5% or more, there are problems such as cracks in the coating film. Moreover, it is generally said that the epoxy-type synthetic resin described in Patent Document 4 has a smaller elongation than the synthetic resin of the cationic styrene butadiene copolymer system.
On the other hand, in the present invention, in adopting the styrene / butadiene copolymer, the compound of the styrene / butadiene copolymer is changed (reduction in the amount of styrene), and further, the compound has a good compatibility with the emulsion (latex) whose composition is changed. In combination, the coating film with an elongation of 5% or more was successfully obtained. Incidentally, when the stability of the coating film is taken into consideration, it is possible to sufficiently follow the deformation of the steel structure by setting the elongation percentage of the coating film formed by the anticorrosive coating composition according to the present invention to 5%. As another configuration, an acryl / styrene copolymer was employed as an anionic synthetic resin in order to promote the flow of nitrite ions (NO ₂ ⁻ ) toward the anode.

When the amount of nitrite (solid content) used in the conventional polymer cement mortar described in Patent Document 3 is increased with respect to the total composition, abnormal setting of the cement occurs. Therefore, the upper limit of the amount of nitrite used is 5% by mass in the case of lithium nitrite and 1.25% by mass in the case of calcium nitrite. However, the amount of nitrite needs to be 2.5% by mass or more in order to maintain a long-term rust-preventing effect as the paint is made. Therefore, in the present invention, the amount of nitrite is increased by setting the amount of styrene / butadiene copolymer to 5% by mass or more, or by setting the amount of acrylic / styrene copolymer to 6% by mass or more. . In addition, by setting the cement amount to 26% by mass or more, the coating film was given an alkaline atmosphere with a pH of 11.5 to 12.5, thereby enabling the reduction of the ground treatment and the long-term corrosion prevention. In addition, in order to ensure the tensile strength, elongation followability, and adhesion strength as a coating material, the compound contains an inorganic powder material and an expansion material.

The nitrite contained in the anticorrosion coating composition according to the present invention is preferably 2.5% by mass or more.
When the nitrite is less than 2.5% by mass, the rust prevention effect is the same as that of an epoxy resin paint, and rust is generated at the crosscut portion in the salt spray test 3000 hours. For example, when the amount of nitrite in the present invention is 3% by mass, the amount of nitrite is about 2.5 times that of the conventional paint.
When a styrene / butadiene copolymer emulsion is selected as the polymer emulsion, the nitrite contained in the anticorrosion coating composition is preferably 7.5% by mass or less.
If the nitrite exceeds 7.5% by mass, the amount of water when mixed with the styrene / butadiene copolymer increases, and voids in the cement hydrate increase. Along with this, moisture easily enters the voids, and the diffusion of nitrite in the cement hydrate is accelerated. As a result, a long-term rust prevention effect cannot be expected.
When an acrylic / styrene copolymer emulsion is selected as the polymer emulsion, the nitrite contained in the anticorrosion coating composition is preferably 9.0% by mass or less.
If the nitrite exceeds 9.0% by mass, the amount of water when mixed with the acrylic / styrene copolymer increases, and voids in the cement hydrate increase. Along with this, moisture easily enters the voids, and the diffusion of nitrite in the cement hydrate is accelerated. As a result, a long-term rust prevention effect cannot be expected.

In the present invention, the anticorrosion coating composition may contain 5 to 18% by mass of the styrene / butadiene copolymer. When the styrene / butadiene copolymer is less than 5% by mass, the styrene / butadiene copolymer emulsion is less than 18 parts by mass with respect to 100 parts by mass of the cement, and the elongation and breaking strength of the coating film are not improved. The followability with respect to the deformation is reduced. For this reason, a coating-film crack is easy to generate | occur | produce and the rust from a crack part advances. On the other hand, when the styrene / butadiene copolymer exceeds 18% by mass, the coating film has a deformation capacity more than necessary, but the coating film adhesion strength is insufficient and the coating film peels off.
Alternatively, the anticorrosion coating composition may contain 6 to 24% by mass of the acrylic / styrene copolymer. When the acrylic / styrene copolymer is less than 6% by mass, the acrylic / styrene copolymer emulsion is less than 11 parts by mass with respect to 100 parts by mass of the cement, and the elongation and breaking strength of the coating film are not improved. The followability with respect to the deformation is reduced. For this reason, a coating-film crack is easy to generate | occur | produce and the rust from a crack part advances. On the other hand, when the acrylic / styrene copolymer exceeds 24% by mass, the coating film has an unnecessarily deformable ability, but the coating film adhesion strength is insufficient and the coating film is peeled off.

Furthermore, in the present invention, the cement contained in the anticorrosion coating composition is 26 to 39% by mass, the inorganic powder material is 20 to 28% by mass, and the expansion material is 0.5 to 1.5% by mass. .
When a styrene / butadiene copolymer emulsion is selected, the cement contained in the anticorrosion coating composition is preferably 26% by mass or more and 39% by mass or less.
When the cement is less than 26% by mass, the water cement ratio exceeds 1.4 when the nitrite and the styrene / butadiene copolymer are properly mixed, and the required coating strength cannot be obtained. Specifically, coating film peeling occurs due to insufficient adhesion strength, and cohesive failure occurs due to insufficient compression strength.
On the other hand, if it exceeds 39% by mass, the required coating strength can be expected, but the amount of cement becomes excessive, the amount of shrinkage increases, and cracks occur on the coating surface.
When an acrylic / styrene copolymer emulsion is selected, the cement contained in the anticorrosion coating composition is preferably 26% by mass or more and 38% by mass or less.
When the cement is less than 26% by mass, the water cement ratio exceeds 1.0 when the nitrite and the acryl / styrene copolymer are properly mixed, and the required coating strength cannot be obtained. Specifically, coating film peeling occurs due to insufficient adhesion strength, and cohesive failure occurs due to insufficient compression strength. On the other hand, if the cement exceeds 38% by mass, the required coating film strength can be expected, but the cement becomes excessive, the shrinkage amount increases, and cracks occur on the coating film surface.

When the inorganic powder material is less than 20% by mass, the coating film becomes cement-rich and the probability of occurrence of cracks during drying increases. In addition, the amount of water increases and the coating strength cannot be secured. On the other hand, when the amount of the inorganic powder exceeds 28% by mass, the amount of aggregate powder is excessively increased, the viscosity of the cement hydrate is decreased, and the adhesive strength of the ground surface is decreased.
The effect of the expansion material can be expected when the amount of cement used is appropriate. When the expansion material is less than 0.5% by mass, when the amount of styrene / butadiene copolymer or acrylic / styrene copolymer is small, the coating film becomes brittle and cannot cope with shrinkage caused by cement. Conversely, when there are many styrene / butadiene copolymers or acrylic / styrene copolymers, the amount of water inevitably increases, the coating film becomes too soft, and the effect of the expanding material cannot be expected. On the other hand, if it exceeds 1.5 mass%, the amount of SO ₃ (sulfur trioxide) in the compound increases and approaches the use limit value (8% in terms of cement mass ratio), which causes expansion cracks.

When a styrene / butadiene copolymer emulsion is selected as the polymer emulsion, the water content is preferably 13 to 42% by mass. The water here is water in the styrene / butadiene copolymer emulsion and in the aqueous nitrous acid solution. If the water content is less than 13% by mass, 2.5% by mass of nitrite cannot be ensured, and if it exceeds 42% by mass, the nitrite exceeds 7.5% by mass, resulting in an excessive specification, resulting in an increase in cost.
When an acrylic / styrene copolymer emulsion is selected as the polymer emulsion, the water content is preferably 12 to 43% by mass. The water here is water in the acrylic / styrene copolymer emulsion and in the aqueous nitrous acid solution. If the water content is less than 12% by mass, 2.5% by mass of nitrite cannot be ensured. If the water content exceeds 43% by mass, the nitrite exceeds 9.0% by mass, resulting in excessive specifications. Cost increases.

Further, in order to reduce white spots and pinholes on the coating surface, the inorganic powder material is one selected from cinnabar powder, calcium carbonate, magnesium silicate, slag powder (steel slag powder, etc.), and clay powder. Or it is 2 or more types. When thin coating is applied during summer construction, it is used as a methyl cellulose thickener to prevent dry-out (a phenomenon in which moisture is removed from the substrate and the hydration reaction is inhibited, resulting in poor curing and poor adhesion). Further, the use of clay powder makes it possible to ensure water retention, and the effect is further improved.

In the anticorrosive coating composition according to the present invention, when the cement is ordinary Portland cement, the nitrite is preferably lithium nitrite. When the nitrite is calcium nitrite, the cement is preferably blast furnace cement.
The clinker produced in the cement manufacturing process is mainly composed of alite, belite, aluminate phase, and ferrite phase. The inventors have discovered that the aluminate phase in the clinker reacts with calcium nitrite, causing abnormal setting of the cement. Therefore, in order to prevent abnormal setting of the cement, it was decided to use lithium nitrite as the nitrite when the cement is ordinary Portland cement. When calcium nitrite was used as the nitrite, blast furnace cement was used to reduce the aluminate phase and prevent abnormal cementation.
In addition, when a blast furnace cement and lithium nitrite are combined, since the setting time is extended, the paint drips during construction, and it becomes difficult to ensure the coating thickness.

The anticorrosion coating film formed by the anticorrosion coating composition is selected from a compound containing cement, an inorganic powder material, and an expansion material, and a styrene / butadiene copolymer or an acrylic / styrene copolymer. It is an anticorrosion coating film containing a polymer and nitrite.
One aspect of the anticorrosion coating film is an anticorrosion coating film containing a styrene / butadiene copolymer as the polymer, wherein 32.5 to 49% by mass of the cement (cement component) and 25 to 35% by mass of the anticorrosion coating film. An inorganic powder material, 0.6 to 1.9% by mass of the expansion material, 6 to 23% by mass of the styrene / butadiene copolymer, 3.1 to 9.4% by mass of the nitrite, It contains 7 to 12% by mass of crystallization water, and the inorganic powder material is one or more selected from cinnabar powder, calcium carbonate, magnesium silicate, slag powder, and clay powder. .
Another aspect of the anticorrosion coating film is an anticorrosion coating film containing an acrylic / styrene copolymer as the polymer, wherein 32.5 to 47.5% by mass of the cement (cement component), 25 to 35 % By mass of the inorganic powder material, 0.6 to 1.9% by mass of the expansion material, 7.5 to 30% by mass of the acrylic / styrene copolymer, and 3.1 to 11.2% by mass of the above-mentioned The inorganic powder material contains nitrite and further contains 7.8 to 12% by mass of crystallization water, and the inorganic powder material is one or two kinds selected from cinnabar powder, calcium carbonate, magnesium silicate, slag powder, and clay powder It is characterized by the above.
In the composition of the above coating film, the content of cement, expansion material, nitrite, etc. represents the content of each raw material component of the coating film, and the content of crystal water depends on the hydration reaction with cement, etc. Corresponds to the amount of water incorporated in the coating.

In any of the above embodiments, the amount of water evaporated as the anticorrosion coating composition was cured was about 20% of the total mass of the anticorrosion coating composition from the experimental results. Therefore, the component ratio of the anticorrosion coating film is obtained by dividing the component ratio of the anticorrosion coating composition by 0.8.

The method for producing an anticorrosive coating composition according to the present invention comprises adding the styrene / butadiene copolymer emulsion or the acrylic / styrene copolymer emulsion to the aqueous nitrite solution when producing the anticorrosive paint composition. And a second step of adding the compound containing the cement, the inorganic powder material, and the expansion material to the mixed solution that has been subjected to the constant temperature pretreatment. It is characterized by that.
Here, “constant temperature pretreatment” means a low-speed stirring for a predetermined time in a state in which a mixed solution obtained by adding a styrene / butadiene copolymer emulsion or an acryl / styrene copolymer emulsion to an aqueous nitrite solution while maintaining a predetermined temperature. Say. The predetermined temperature is preferably 30 to 60 ° C., for example, around 40 ° C., and the predetermined time is preferably 3 to 10 minutes, for example, about 5 minutes. It is more preferable to leave the premixed mixture at a constant temperature for 5 to 10 days, for example, about 7 days, and then add the compound to the mixture.

In the present invention, the viscosity of the admixture is adjusted to a styrene / butadiene copolymer emulsion or acrylic by pretreating a mixture obtained by adding a styrene / butadiene copolymer emulsion or an acrylic / styrene copolymer emulsion to an aqueous nitrite solution. / It becomes possible to reduce to about 1/40 of the viscosity of the styrene copolymer emulsion alone. As a result, significant improvement can be expected with respect to the kneading effect with the compound. In addition, it becomes a long-term stable admixture and can be stored for a long time.

Further, the steel material corrosion prevention method according to the present invention removes floating rust on the steel material surface, and then applies an undercoat material comprising the anticorrosive coating composition to the steel material surface to form an undercoat layer, and an elongation of 5% or more. An overcoating material for forming a coating film having a rate is applied on the undercoating layer to form an overcoating layer.
And the coating-film layer which concerns on this invention is formed from the undercoat layer which consists of the said anti-corrosion coating film, and the top-coat layer which consists of a coating film which has an elongation rate of 5% or more, It is characterized by the above-mentioned.

Here, the above-mentioned elongation rate is described in “Reference Material 2 Quality Test Method for Polymer Cement-based Coating Waterproofing Material” in “Arrangement Guidelines for Polymer Cement-Based Coating Waterproof Film (draft) / Description” edited by the Architectural Institute of Japan. It is a value determined by a measuring method based on “3. Tensile strength and elongation test at break”.

In the present invention, since the undercoat layer becomes alkaline (pH 11.5 or more) by the cement contained in the anticorrosion coating composition, a passive film (Fe ₂ O ₃ ) is formed on the steel material surface, and rusting is prevented. (Alkaline anti-corrosion function). This eliminates the need for advanced substrate adjustment on the surface of the steel material, thereby reducing costs. For example, the base material may be adjusted to about 3 types of keren to remove floating rust from the surface of the steel material. When the passive film is damaged due to some external factor, nitrite is eluted to reconstruct the passive film (self-repair function). In addition, the undercoat layer is provided with flexibility by the styrene / butadiene copolymer or the acrylic / styrene copolymer, and an undercoat layer that can follow the deformation of the steel surface is formed.

In addition, the elongation rate of the anticorrosive coating film according to the present invention is, as described above, because the elongation when the bending axial force is applied to the steel material is 0.5% or more, and the stability of the coating film is considered. In order for the top coat film to follow the elongation of the undercoat layer, the elongation percentage of the top coat film needs to be 5% or more.
The overcoat layer may include at least one selected from an epoxy resin, a urethane resin, a polyurethane resin, an acrylic silicon resin, an acrylic urethane resin, a Halth hybrid resin, and the like, or may be composed of a coating film. The topcoat layer may be a single coating film or may be composed of two or more coating films.
The total thickness of the overcoat layer is not particularly limited, but may be, for example, 60 to 130 μm. For example, it may be composed of a first layer having a layer thickness of 60 to 80 μm and a second layer having a layer thickness of 20 to 40. Alternatively, it may be composed of a first layer having a layer thickness of 40 to 70 μm and a second layer having a layer thickness of 30 to 40 μm.

The anticorrosion coating composition of the present invention comprises a compound containing cement, an inorganic powder material, and an expansion material, a styrene / butadiene copolymer emulsion or an acrylic / styrene copolymer emulsion, and a nitrite. It is a composition. In order to make the amount of nitrite 2.5% by mass or more, 5% by mass or more of styrene / butadiene copolymer or 6% by mass or more of acrylic / styrene copolymer emulsion is contained. In addition, the cement amount of the entire composition is set to 26% by mass or more. As a result, the coating film was given an alkaline atmosphere with a pH of 11.5 to 12.5, and the surface treatment was reduced and anticorrosion was possible for a long period of time. In addition, since the cement paste after curing appropriately contains nitrite used as a rust preventive agent, the diffusion speed of nitrite is reduced, and the effect of nitrite can be maintained for a long time.

Further, in the present invention, when the anticorrosion coating composition is produced, a mixed solution obtained by adding a styrene / butadiene copolymer emulsion or an acrylic / styrene copolymer emulsion to an aqueous nitrite solution in advance is subjected to a constant temperature pretreatment. Therefore, the viscosity of the mixed solution can be reduced to about 1/40 of the viscosity of the styrene / butadiene copolymer emulsion alone or the viscosity of the acrylic / styrene copolymer emulsion alone. As a result, significant improvement can be expected with respect to the kneading effect with the compound.

Furthermore, in the present invention, since the undercoat layer is alkaline, a passive film is formed on the steel surface, and rusting is prevented. This eliminates the need for advanced substrate adjustment on the steel surface. If the passive film is damaged by any external factor, nitrite will elute and reconstruct the passive film. In addition, the undercoat layer is provided with flexibility by the styrene / butadiene copolymer or the acrylic / styrene copolymer, and an undercoat layer that can follow the deformation of the steel surface is formed.

Subsequently, embodiments embodying the present invention will be described, but the present invention is not limited to the following embodiments at all, and other conceivable within the scope of the matters described in the claims. These embodiments and modifications are also included.

[Prime material]
The present invention is an anticorrosion coating composition used as a primer on the surface of a steel material. In a mixed solution obtained by adding a styrene / butadiene copolymer emulsion or an acrylic / styrene copolymer emulsion to an aqueous nitrite solution and pre-isothermal treatment, It is produced by adding a compound containing cement, an inorganic powder material and an expansion material. At this time, the styrene / butadiene copolymer is preferably 5 to 18% by mass and the nitrite is preferably 2.5 to 7.5% by mass. Alternatively, it is preferable that the acrylic / styrene copolymer is 6 to 24% by mass and the nitrite is 2.5 to 9.0% by mass.
In order to ensure durability that does not reduce the rust prevention quality and to ensure a predetermined base coating thickness (200 μm to 650 μm), 10 to 18% by mass of styrene / butadiene copolymer and 3 to 4.5% of nitrite. More preferably, the content is 10% by mass or the acrylic / styrene copolymer is 10 to 20% by mass and the nitrite is 4 to 6.5% by mass. In addition, when a mixed solution obtained by adding a styrene / butadiene copolymer emulsion or an acryl / styrene copolymer emulsion to an aqueous nitrite solution is pretreated at a constant temperature, the amount of nitrite can be easily increased.

When a styrene / butadiene copolymer is used, the compounding ratio is more preferably 50 to 70% by mass based on the total composition. When an acrylic / styrene copolymer is used, it is more preferably 50-60% by mass of the total composition.
In order to prevent cracking of the coating film, the inorganic powder material is made 20 to 28% by mass, and in order to suppress the SO ₃ (sulfur trioxide) amount of the coating film, the expansion material is made 0.5 to 1% by mass. More preferably.

Nitrite is a substance that imparts a rust prevention effect. Lithium nitrite, sodium nitrite, potassium nitrite, calcium nitrite, magnesium nitrite, barium nitrite and the like can be used, but lithium nitrite and calcium nitrite have good compatibility with cement.

Cement keeps the coating film alkaline and has a function as a binder. Cement is not particularly limited, and various portland cements, various mixed cements, blast furnace cement, fly ash cement, etc. can be used. When calcium nitrite is used as the nitrite, use blast furnace cement to improve fluidity. Is preferred.

The inorganic powder material enhances the dispersibility and adhesion of the compound. As the inorganic powder material, cinnabar powder such as natural cinnabar and regenerated cinnabar, clay powder or calcium carbonate or slag powder can be used, among which calcium carbonate, magnesium silicate, slag powder and clay powder are selected. It is preferable to use two or more species.
When the compound is only cement and an expanding material, the coating thickness cannot be secured, and the coating contracts as the cement hardens. For these reasons, it is necessary to add an inorganic powder material to the anticorrosive coating composition. In this case, a stable coating film cannot be obtained unless the particle size of the inorganic powder material is reduced to about 1/3 of the minimum coating film thickness. Therefore, the particle size distribution of the inorganic powder material is such that the minimum coating thickness is 200 μm and the ratio of the inorganic powder material of 74 μm or less is 80% or more.

¡Expansion material is used to prevent dry shrinkage of the compound. A commercially available material such as anhydrous gypsum can be used as the expansion material.

Furthermore, in addition to the above materials, a water reducing agent for reducing moisture and increasing fluidity, a thickening agent for increasing viscosity, and the like may be added as an admixture. When a styrene / butadiene copolymer is used, the amount of the admixture is preferably 0.4 to 0.8% by mass, and more preferably 0.6% by mass. When an acrylic / styrene copolymer is used, the amount of the admixture is preferably 0.3 to 0.6% by mass, and more preferably 0.4% by mass.

For coating using the anticorrosive coating composition according to the present invention, epoxy resin coating, alkali coating, and heavy anticorrosion coating, the expected life of each coating is 30 years, 7 years, 8 years, 10 years, material costs and temporary construction As a result of calculating the total cost such as costs, assuming that the total cost when using the anticorrosive coating composition according to the present invention is 1, it is 5.0 for epoxy resin coating, 4.1 for alkali coating, and 5 for heavy anticorrosion coating. 0.0. This also shows that the life cycle cost of a steel structure can be significantly reduced by using the anticorrosion coating composition according to the present invention.

[Coating material]
The coating film formed on the undercoat layer made of the anticorrosive coating composition is required to have a substrate follow-up property, nitrite elution prevention, and excellent weather resistance. Although a combination of an epoxy resin, a urethane resin, and the like having a high deformation capability can be handled, a coating material having high weather resistance will be described here. For example, as a topcoat material used for a topcoat layer formed directly on the undercoat layer, a two-component mixed paint in which a solution obtained by dissolving an acrylic silicon resin in a terpene-based weak solvent is used as a main agent and an isocyanate is hardened. Can be used. The mixing ratio of the main agent and the curing agent is preferably 2 to 15 parts by mass of the main agent with respect to 1 part by mass of the curing agent.

In the top coating material, an acrylic silicon resin having excellent weather resistance is used as the main component of the main agent, and by mixing isocyanate as a curing agent, the OH group of the main agent and the isocyanate group of the curing agent are combined to form a coating film. Urethane crosslinks are formed in the molecular structure. Thereby, the molecular structure of a coating film becomes a three-dimensional network structure, and the sealing property of a coating film improves. That is, it is possible to prevent nitrite contained in the undercoat layer from eluting into the topcoat layer. Moreover, when forming urethane bridge | crosslinking, foundation | substrate followability is ensured by making bridge | crosslinking density (ratio of the number of the crosslinking points with respect to the whole structural unit) low, and softening (a pencil hardness is about H).

In addition, the overcoat layer is required to have excellent weather resistance that can maintain gloss over a long period of time. Therefore, as another example of the topcoat material used for forming the topcoat layer, a two-component mixed paint using a solution obtained by dissolving a Hals hybrid resin in a strong solvent such as toluene or xylene as a main agent and an isocyanate as a curing agent is used. Can be used. The mixing ratio of the main agent and the curing agent is preferably 2 to 15 parts by mass of the main agent with respect to 1 part by mass of the curing agent, as in the case of the top coating material.

The Hals hybrid resin, which is the main component of the main agent, is an acrylic polyol resin obtained by copolymerizing a hindered amine light stabilizer (Hindered Amine Light Stabilizer) and cyclohexyl methacrylate. The hindered amine light stabilizer (hereinafter referred to as “HALS”) captures radicals generated by ultraviolet rays and reacts with the oxygen in the air when the radicals are generated. The phenomenon of radical generation and deterioration of the coating). On the other hand, cyclohexyl methacrylate has high hydrophobicity in addition to not having a benzene skeleton that easily absorbs sunlight and generates radicals. Hals Hybrid resin chemically binds HALS into the resin to prevent bleed out of HALS, suppresses the auto-oxidative degradation reaction of the coating film for a long time, and the high hydrophobicity of cyclohexyl methacrylate makes the coating film Long life has been achieved.

Furthermore, by mixing the main agent and the curing agent, the OH group of the main agent and the isocyanate group of the curing agent are combined to form a urethane bridge in the molecular structure, so the molecular structure of the coating film is a three-dimensional network structure. Thus, the sealing property of the coating film is improved.

[Anti-corrosion method for steel]
Next, a method for preventing corrosion of steel according to an embodiment of the present invention will be described by taking as an example the repainting of an existing structure that has undergone corrosion.
(1) High-pressure water pressurized to a water pressure of about 15 MPa to 25 MPa by a high-pressure water generator (not shown) is sprayed from the nozzle toward the steel material surface to adjust the surface of the steel material (base adjustment). The degree of substrate preparation is about 3 types of keren (same level as SSPC-SP2 or SIS St2), that is, the old paint film and floating rust are removed to reveal the steel surface. Drop it to make it a clean surface. The substrate may be adjusted using sand blasting or an electric tool.
(2) An undercoat layer made of the above-described anticorrosion coating composition is applied to the surface of the steel material that has been prepared to form an undercoat layer. At this time, the thickness of the undercoat layer is set to 200 μm to 650 μm. The standard drying time is about one day, but it varies depending on environmental conditions such as humidity.

(3) A first overcoat layer is formed by applying a solution obtained by dissolving an acrylic silicon resin in a weak solvent and an isocyanate and mixing and stirring on the undercoat layer. At this time, the thickness of the first overcoat layer is set to 60 μm to 80 μm. The standard drying time is about one day, but it varies depending on environmental conditions such as humidity.
(4) A second topcoat layer is formed by applying a solution obtained by dissolving a Hals hybrid resin in a strong solvent and an isocyanate and mixing the stirred topcoat onto the first topcoat layer. At this time, the thickness of the second overcoat layer is set to 20 μm to 40 μm. The standard drying time is about one day, but it varies depending on environmental conditions such as humidity.

In addition, each application | coating method of undercoat and 1st and 2nd topcoat may be any of brush coating, roller coating, and spray coating. When it rains after application, the next coating is performed after about 3 days.

Examples according to the present invention will be described below.
[First Example]
In the first embodiment, a styrene / butadiene copolymer was used.
[Composite cycle test]
A composite cycle test was performed on a test piece in which an undercoat material and an overcoat material were applied to a strip-shaped steel plate that had been subjected to a surface base treatment. Tables 1, 2 and 3 show the material configurations and properties of the topcoat materials of the examples and reference examples subjected to the combined cycle test, and Table 4 shows the test results. In addition, Table 5, Table 6, Table 7, and Table 8 show the material configurations and test results of the comparative examples. Here, the reference example uses an anti-corrosion coating composition according to the present invention as an undercoat material and an overcoat material having a coating film elongation of less than 5%.
In each of the examples, reference examples, and comparative examples, two test pieces were used, and each test piece was coated with a top coat material, and then a ruler was applied to the surface of the test piece and a cross cut was made with a cutter knife.

Examples A1 to A6 used lithium nitrite as the nitrite contained in the primer, and Examples A7 to A11 used calcium nitrite. In Examples A1 to A6, ordinary Portland cement was used, and in Examples A7 to A11, blast furnace cement was used. At this time, as the inorganic powder material, a combination of calcium carbonate and magnesium silicate and clay powder in Examples A1, A3 to A5, a combination of dredged sand powder and clay powder in Example A8, and a slag in Example A11 A combination of powder (iron slag powder) and clay powder, slag powder in Example 2, calcium carbonate and magnesium silicate in Examples A6 and 9, cinnabar powder in Example A7, and clay powder in Example A10 did.

On the other hand, the overcoat layer has a two-layer structure composed of two types of topcoat materials different for each example, and the total thickness is set to 80 μm or 100 μm. The crosslink density of the topcoat material is a comparative evaluation of the crosslink densities of Examples A1 to A11 with respect to the average value of the first topcoat layer and the second topcoat layer. Similarly, the elongation percentage of the top coat material is an average value of the first top coat layer and the second top coat layer.

In Reference Examples A1 to A4, lithium nitrite was used as the nitrite contained in the primer and the cement was ordinary Portland cement. In Reference Example A5, calcium nitrite was used as the nitrite contained in the primer, and the cement was blast furnace cement. For inorganic powder materials, Reference Examples A1, A4 and A5 are calcium carbonate and magnesium silicate, Reference Example A2 is a combination of slag powder and clay powder, Reference Example A3 is calcium carbonate and magnesium silicate and clay powder. Each combination was used. On the other hand, for the top coat material, reference examples A1 and A2 used epoxy resins, reference example A3 used weak solvent silicone epoxy resins, and reference examples A4 and A5 used modified silicone epoxy resins.

As an undercoat material for Comparative Examples A1 to A3, Mighty CF manufactured by Mighty Chemical Co., Ltd., mainly composed of white cement and ultrafine silica was used. For the undercoat materials of Comparative Examples A4 and A5, Tomolic (registered trademark) made by Primet Technology Co., Ltd., mainly composed of silicon resin and zinc powder, was used. Further, the undercoat material of Comparative Examples A6 and A7 was an alkali paint, the undercoat material of Comparative Example A8 was a zinc rich paint, and the undercoat material of Comparative Example A9 was an epoxy resin paint. Comparative Examples A10 to A12 are paints comprising the same components as in the present invention, but the blending ratio is outside the scope of the present invention.
On the other hand, as for the overcoat material of Comparative Examples A1 to A12, only Comparative Example A7 used a chlorinated olefin-based paint, and other Comparative Examples used epoxy resin.

In Comparative Examples A13, A14, A17 to A21, A23, A24, A29, and A30, lithium nitrite was used as the nitrite contained in the primer, and ordinary Portland cement was used as the cement. Comparative Examples A15, A16, A22, A25 to A28, and A31 to 34 used calcium nitrite as the nitrite contained in the primer and blast furnace cement as the cement. Moreover, as an inorganic type powder material, in Comparative Examples A13, A14, A16, A25, and A26, a combination of calcium carbonate and magnesium silicate and clay powder is used, and in Comparative Example A27, a combination of cinnabar powder and clay powder. In Comparative Examples A30 and A31, a combination of slag powder and clay powder is used. In Comparative Examples A15, A19, A20, and A32 to A34, calcium carbonate and magnesium silicate are used, and Comparative Examples A17 and A18 are used. A28 used cinnabar powder, Comparative Examples A21, A22 and A29 used slag powder, and Comparative Examples A23 and A24 used clay powder.
On the other hand, the overcoat material of Comparative Examples A13 to A34 was a weak solvent acrylic urethane resin, and the thickness was all 180 μm.

The coating amount was 1.0 kg / m ² for the undercoat material and 0.4 to 0.5 kg / m ² for the top coat material. In addition, each coating-film thickness of Table 2, Table 5, and Table 7 is a measured value with a film thickness meter.

In the combined cycle test, a cass spray test was carried out at 35 ° C. for 4 hours, then dried at 60 ° C. and a humidity of 50% for 2 hours, and further a moisture resistance test at a temperature of 50 ° C. and a humidity of 95%. The test for a total of 8 hours that is performed for 2 hours is defined as one cycle, and a plurality of cycles are performed.

The cast spray test is a test in which the test solution is changed from salt water to a cast solution in the salt spray test method according to JIS Z 2371. The cast solution is an aqueous solution containing 40 g / L of sodium chloride and 0.205 g / L of cupric chloride and adjusted to pH 3.0 with acetic acid.
The moisture resistance test was performed in accordance with JIS K 5600-7-3 moisture resistance (discontinuous condensation method).

The combined cycle test was conducted 200 times. In each of the Examples, Reference Examples, and Comparative Examples, the rust generation state (rust prevention effect) on the surface of the two test pieces was evaluated based on the criteria shown in Table 9, with a maximum of 10 points. The average of the evaluation points was obtained. In addition, the comprehensive evaluation in Table 4, Table 6, and Table 8 is the result of comprehensively evaluating the rust prevention effect, the workability, the ground followability, and the weather resistance.

From these tables, the following can be understood.
a) Although all of the examples have high antirust effects and some workability is poor, they are generally highly evaluated.
b) Although all of the reference examples are excellent in the rust prevention effect and workability, the base coatability is poor because the elongation rate of the topcoat layer is as low as less than 5%. Therefore, the overall evaluation is low.
c) All of the comparative examples have a low rust prevention effect and a low overall evaluation.
d) The overall evaluation of the examples using the top coating material having a high crosslinking density and an elongation of 5% or more is high. That is, it can be seen that a paint having both the sealing property of the coating film and the base following property is desirable as the top coating material.

[Mixing stability]
A mixture of lithium nitrite aqueous solution with styrene / butadiene copolymer emulsion and a mixture of calcium nitrite aqueous solution with styrene / butadiene copolymer emulsion immediately after the isothermal pretreatment and 7 days after the isothermal pretreatment Table 10 shows the properties after standing. Here, the mass ratio of the aqueous nitrous acid solution to the styrene / butadiene copolymer emulsion is 1: 4. The viscosity is measured using a BH viscometer at a rotation speed of 20 rpm. From the same table, it can be seen that the properties are stable with no significant changes in the concentration, viscosity, and pH immediately after the constant temperature pretreatment and after standing for 7 days.
The viscosity of both admixtures is 40 to 50 mPa · s, which indicates that the fluidity is greatly improved compared to the viscosity of 600 to 800 mPa · s of the styrene / butadiene copolymer emulsion alone.

[Tensile strength test]
This test determines the tensile strength of a coating film. Table 11 shows the composition of the anticorrosion coating composition of Example A12. In the case of a coating film, a tensile strength of 0.5 to 1.0 N / mm ² or more is necessary, but the tensile strength of Example A12 is 1.5 N / mm ² , and it has a sufficient tensile strength as a coating film. .

[Break elongation test]
This test involves determining the elongation at break of a coating film. The formulation in the examples is the same as in the tensile test. In order to follow the deformation of the base material, in the case of a steel material, an elongation of 0.5% or more is necessary, but the breaking elongation of the example is 5%, and the base material can be sufficiently deformed as a coating film. Can follow. Incidentally, in the case of the conventional product, the breaking elongation is at a level of 1.4%.

[Adhesion strength test]
This test determines the degree of adhesion between the base material and the coating film. This time, it was carried out according to the provisions of JIS A 6203 “Polymer dispersion for cement admixture and re-emulsified powder resin”. Table 12 shows the composition of the anticorrosion coating composition of Example A13. Example adhesion strength of A13 is 1.1 N / mm ^2, bond strength of 1.0N JIS A bond strength of 6916 to a defined thin intermediate coating material 0.5 N / mm ² and a thickness intermediate coating material / Mm ² is satisfied.

[Second Example]
In the second example, an experiment was performed using an acrylic / styrene copolymer.

[Composite cycle test]
A composite cycle test was performed on a test piece in which an undercoat material and an overcoat material were applied to a strip-shaped steel plate that had been subjected to a surface base treatment. Tables 13, 14, and 15 show the material configurations and properties of the topcoat materials of Examples and Reference Examples in which combined cycle tests were performed, and Table 16 shows the test results. In addition, Table 17, Table 18, Table 19, and Table 20 show the material configurations and test results of the comparative examples. Here, the reference example uses an anti-corrosion coating composition according to the present invention as an undercoat material and an overcoat material having a coating film elongation of less than 5%.
In each of the examples, reference examples, and comparative examples, two test pieces were used, and each test piece was coated with a top coat material, and then a ruler was applied to the surface of the test piece and a cross cut was made with a cutter knife.

Examples B1 to B6 used lithium nitrite as the nitrite contained in the primer, and Examples B7 to B11 used calcium nitrite. In Examples B1 to B6, ordinary Portland cement was used, and in Examples B7 to B11, blast furnace cement was used. At this time, as inorganic powder materials, in Examples B1 and B3 to B5, a combination of calcium carbonate and magnesium silicate and clay powder, in Example B8, a combination of dredged sand powder and clay powder, in Example B11, slag A combination of powder (steel slag powder) and clay powder, slag powder in Example B2, calcium carbonate and magnesium silicate in Examples B6 and B9, cinnabar powder in Example B7, and clay powder in Example B10 did.

On the other hand, the overcoat layer has a two-layer structure composed of two types of topcoat materials different for each example, and the total thickness is set to 80 μm or 100 μm. The crosslink density of the topcoat material is an average value of the first topcoat layer and the second topcoat layer, and is a comparative evaluation of the crosslink densities of Examples B1 to B11. Similarly, the elongation percentage of the top coat material is an average value of the first top coat layer and the second top coat layer.

In Reference Examples B1 to B4, lithium nitrite was used as the nitrite contained in the primer, and the cement was ordinary Portland cement. In Reference Example B5, calcium nitrite was used as the nitrite contained in the primer, and the cement was blast furnace cement. Regarding inorganic powder materials, Reference Examples B1, B4, and B5 are calcium carbonate and magnesium silicate, Reference Example B2 is a combination of slag powder and clay powder, and Reference Example B3 is calcium carbonate and magnesium silicate and clay powder. Each combination was used.
On the other hand, for the topcoat material, Reference Examples B1 and B2 used epoxy resins, Reference Example B3 used weak solvent silicone epoxy resins, and Reference Examples B4 and B5 used modified silicone epoxy resins.

For the undercoat material of Comparative Examples B1 to B3, Mighty CF manufactured by Mighty Chemical Co., Ltd., mainly composed of white cement and ultrafine silica was used. For the undercoat materials of Comparative Examples B4 and B5, Tomolic (registered trademark) made by Primet Technology Co., Ltd., mainly composed of silicon resin and zinc powder, was used. Further, the undercoat material of Comparative Examples B6 and B7 was an alkali paint, the undercoat material of Comparative Example 8 was a zinc rich paint, and the undercoat material of Comparative Example B9 was an epoxy resin paint. Comparative Examples B10 to B12 are paints comprising the same components as in the present invention but having a blending ratio outside the scope of the present invention.
On the other hand, for the overcoat materials of Comparative Examples B1 to B12, only Comparative Example B7 used a chlorinated olefin-based paint, and the other Comparative Examples used epoxy resins.

In Comparative Examples B13, B14, B17 to B21, B23, B24, B29, and B30, lithium nitrite was used as the nitrite contained in the primer, and ordinary Portland cement was used as the cement. In Comparative Examples B15, B16, B22, B25 to B28, and B31 to B34, calcium nitrite was used as the nitrite contained in the primer and blast furnace cement was used as the cement. Further, as inorganic powder materials, in Comparative Examples B13, B14, B16, B25, and B26, a combination of calcium carbonate and magnesium silicate and clay powder is used, and in Comparative Example B27, a combination of cinnabar powder and clay powder is used. In Comparative Examples B30 and B31, a combination of slag powder and clay powder is used. In Comparative Examples B15, B19, B20, and B32 to B34, calcium carbonate and magnesium silicate are used, and Comparative Examples B17 and B18 are used. , B28 used cinnabar powder, Comparative Examples B21, B22 and B29 used slag powder, and Comparative Examples B23 and B24 used clay powder.
On the other hand, the overcoat material of Comparative Examples B13 to B34 was a weak solvent acrylic urethane resin, and the thickness was all 180 μm.

The coating amount was 1.0 kg / m ² for the undercoat material and 0.4 to 0.5 kg / m ² for the top coat material. In addition, each coating-film thickness of Table 13, Table 17, and Table 19 is a measured value with a film thickness meter.

The above-mentioned cast spray test is a test in which the test solution is changed from salt water to a cast solution in the salt spray test method according to JIS Z 2371. The cast solution is an aqueous solution containing 40 g / L of sodium chloride and 0.205 g / L of cupric chloride and adjusted to pH 3.0 with acetic acid. The moisture resistance test was performed in accordance with JIS K 5600-7-3 moisture resistance (discontinuous condensation method).

The combined cycle test was conducted 200 times. In each of the Examples, Reference Examples, and Comparative Examples, the rust generation state (rust prevention effect) on the surface of the two test pieces was evaluated based on the criteria shown in Table 21, with a maximum of 10 points. The average of the evaluation points was obtained. In addition, the comprehensive evaluation in Table 16, Table 18, and Table 20 is the result of comprehensively evaluating the rust prevention effect, the workability, the ground followability, and the weather resistance.

[Mixing stability]
Immediately after the isothermal pretreatment and 7 days after the isothermal pretreatment for each of the admixture obtained by adding an acrylic / styrene copolymer emulsion to an aqueous lithium nitrite solution and the admixture obtained by adding an acrylic / styrene copolymer emulsion to an aqueous calcium nitrite solution Table 22 shows the properties after standing. Here, the mass ratio between the aqueous nitrous acid solution and the acrylic / styrene copolymer emulsion is 3: 4. The viscosity is measured using a BH viscometer at a rotation speed of 20 rpm. From the same table, it can be seen that the properties are stable with no significant changes in the concentration, viscosity, and pH immediately after the constant temperature pretreatment and after standing for 7 days.
The viscosity of both admixtures is 40 to 50 mPa · s, and it can be seen that the fluidity is greatly improved as compared with the viscosity of the acrylic / styrene copolymer emulsion alone of 1500 to 1600 mPa · s.

[Tensile strength test]
This test determines the tensile strength of a coating film. Table 23 shows the composition of the anticorrosion coating composition of Example B12. In the case of a coating film, a tensile strength of 0.5 to 1.0 N / mm ² or more is necessary, but the tensile strength of Example B12 is 1.5 N / mm ² , and it has a sufficient tensile strength as a coating film. .

[Adhesion strength test]
This test determines the degree of adhesion between the base material and the coating film. This time, it was carried out according to the provisions of JIS A 6203 “Polymer dispersion for cement admixture and re-emulsified powder resin”. Table 24 shows the composition of the anticorrosion coating composition of Example B13. Implementation adhesion strength of Example B13 is 1.1 N / mm ^2, bond strength of 1.0N JIS A bond strength of 6916 to a defined thin intermediate coating material 0.5 N / mm ² and a thickness intermediate coating material / Mm ² is satisfied.

The coating film formed on the steel material surface using the anticorrosion coating composition of the present invention has an alkaline atmosphere with a pH of 11.5 to 12.5. If a coating film layer having such a coating film as an undercoat layer is formed, a passive film is formed on the steel material surface, and rusting is prevented. Moreover, since the nitrite is appropriately held by the cement paste, the rust preventive effect by the nitrite can be maintained for a long time. Further, the polymer made of styrene / butadiene copolymer or acrylic / styrene copolymer imparts flexibility to the undercoat layer and can follow the deformation of the steel surface. These effects eliminate the need for advanced substrate preparation on the steel surface and enable long-term corrosion protection.

Claims

Anticorrosion comprising a compound containing cement, an inorganic powder material and an expansion material, a polymer emulsion selected from an emulsion containing a styrene / butadiene copolymer or an emulsion containing an acrylic / styrene copolymer, and nitrite Sex composition.
The anticorrosive composition according to claim 1, wherein the polymer emulsion is a styrene / butadiene copolymer emulsion,
26 to 39% by mass of the cement, 20 to 28% by mass of the inorganic powder material, 0.5 to 1.5% by mass of the expansion material, 5 to 18% by mass of the styrene / butadiene copolymer, 2 Containing 5 to 7.5% by weight of the nitrite,
Further, it contains 13 to 42% by mass of water, and the inorganic powder material is one or more selected from cinnabar powder, calcium carbonate, magnesium silicate, slag powder, and clay powder. Anticorrosion paint composition.
The anticorrosive composition according to claim 1, wherein the polymer emulsion is an acrylic / styrene copolymer emulsion,
26 to 38% by mass of the cement, 20 to 28% by mass of the inorganic powder, 0.5 to 1.5% by mass of the expansion material, 6 to 24% by mass of the acrylic / styrene copolymer; 5 to 9.0% by weight of the nitrite,
Further, it contains 12 to 43% by mass of water, and the inorganic powder material is one or more selected from cinnabar powder, calcium carbonate, magnesium silicate, slag powder, and clay powder. Anticorrosion paint composition.
The anticorrosion coating composition according to any one of claims 1 to 3, wherein the cement is a blast furnace cement and the nitrite is calcium nitrite.
The anticorrosion coating composition according to any one of claims 1 to 3, wherein the cement is ordinary Portland cement and the nitrite is lithium nitrite.
A method for producing an anticorrosive coating composition according to any one of claims 1 to 3,
A first step of isothermal pretreatment of a mixed solution obtained by adding the polymer emulsion selected from a styrene / butadiene copolymer emulsion or an acrylic / styrene copolymer emulsion to the aqueous nitrite solution; and the isothermal pretreatment The manufacturing method of the anticorrosion coating composition which has a 2nd process of adding the said compound containing the said cement, the said inorganic type powder material, and the said expansion | swelling material to a liquid mixture.
5. The method for producing an anticorrosive coating composition according to claim 4, wherein the polymer emulsion selected from a styrene / butadiene copolymer emulsion or an acrylic / styrene copolymer emulsion is added to the aqueous nitrite solution. Anticorrosion comprising: a first step of pretreating a mixed solution at a constant temperature; and a second step of adding the compound containing the cement, the inorganic powder material, and the expansion material to the mixed solution subjected to a constant temperature pretreatment. A method for producing a coating composition.
6. The method for producing an anticorrosive coating composition according to claim 5, wherein the polymer emulsion selected from a styrene / butadiene copolymer emulsion or an acryl / styrene copolymer emulsion is added to the aqueous nitrite solution. Anticorrosion comprising: a first step of pretreating a mixed solution at a constant temperature; and a second step of adding the compound containing the cement, the inorganic powder material, and the expansion material to the mixed solution subjected to a constant temperature pretreatment. A method for producing a coating composition.
After removing floating rust on the surface of the steel material, an undercoating material comprising the anticorrosive coating composition according to any one of claims 1 to 3 is applied to the surface of the steel material to form an undercoating layer, and an elongation of 5% or more An anti-corrosion method for a steel material, wherein an overcoat layer for forming a coating film having a rate is applied on the undercoat layer to form an overcoat layer.
After removing floating rust on the surface of the steel material, an undercoat composed of the anticorrosive coating composition according to claim 4 is applied to the surface of the steel material to form an undercoat layer, and a coating film having an elongation of 5% or more is formed. A method for preventing corrosion of a steel material, comprising: applying an overcoat material on the undercoat layer to form an overcoat layer.
After removing floating rust on the steel material surface, an undercoat material comprising the anticorrosive coating composition according to claim 5 is applied to the steel material surface to form an undercoat layer, and a coating film having an elongation of 5% or more is formed. A method for preventing corrosion of a steel material, comprising: applying an overcoat material on the undercoat layer to form an overcoat layer.
An anticorrosive coating film comprising a compound containing cement, an inorganic powder material and an expansion material, a polymer selected from a styrene / butadiene copolymer or an acrylic / styrene copolymer, and nitrite.
The anticorrosion coating film according to claim 12, wherein the polymer is a styrene / butadiene copolymer,
32.5 to 49% by mass of the cement, 25 to 35% by mass of the inorganic powder, 0.6 to 1.9% by mass of the expansion material, and 6 to 23% by mass of the styrene / butadiene copolymer. 3.1 to 9.4% by mass of the nitrite,
Further, it contains 7 to 12% by mass of crystal water, and the inorganic powder material is one or more selected from cinnabar powder, calcium carbonate, magnesium silicate, slag powder, and clay powder. Anticorrosion coating.
The anticorrosion coating film according to claim 12, wherein the polymer is an acrylic / styrene copolymer,
32.5 to 47.5% by mass of the cement, 25 to 35% by mass of the inorganic powder, 0.6 to 1.9% by mass of the expansion material, 7.5 to 30% by mass of the acrylic / A styrene copolymer, 3.1 to 11.2% by mass of the nitrite,
Further, 7.8 to 12% by mass of crystallization water is included, and the inorganic powder material is one or more selected from cinnabar powder, calcium carbonate, magnesium silicate, slag powder, and clay powder. Characteristic anticorrosion coating.
A coating layer comprising: an undercoat layer comprising the anticorrosion coating film according to any one of claims 12 to 14; and an overcoat layer comprising a coating film having an elongation of 5% or more.