JP2018070764A - Exterior coating material for electrolytically protecting reinforced concrete, and anode film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exterior coating material further improving the weather resistance of the exterior coated film of an inorganic material-based building, and an exterior coating material forming an anode film provided with conductivity, gas permeability and water permeability for electrolytically protecting reinforced concrete.SOLUTION: Provided is an exterior coating material for an inorganic material-based building obtained by mixed into a solvent containing: sulfonic acid graft polymerization type PTFE as the main component, in which the equivalent of sulfonic acid in the main component is 921 or higher; and water in the state where the main component lies in the range of 1 to 10 mass% or in the range of 1.5 to 8 mass%. Alternatively, provided is an exterior coating material for electrolytically protecting reinforce concrete obtained by being mixed into a solvent in which the equivalent of sulfonic acid in the main component lies in the range of 800 to 1,170, and the main component lies in the range of 1 to 10 mass% or in the range of 2 to 4 mass%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exterior coating and an anode coating for reinforced concrete cathodic protection, and specifically, an exterior of a building in which the exterior is formed of an inorganic material (typically concrete, a new building material of an inorganic material, etc.). The present invention relates to a coating material, an exterior coating material suitable for forming a coating used as an anode for electrocorrosion protection of a reinforcing steel (or steel frame, hereinafter referred to as “reinforcing bar”) concrete, and an anode coating for reinforced concrete electrocorrosion protection.

  In various types of buildings such as ordinary houses, high-rise houses, office buildings, factory buildings, etc., contamination by air dust, acid factors such as acid rain or carbon dioxide in the air, and even sunlight make use of inorganic materials. It is known that outer wall materials or roof materials (hereinafter collectively referred to as exterior materials) deteriorate. In order to suppress such deterioration of the exterior material, a protective film is formed on the surface by painting or the like. For example, Patent Document 1 proposes an aqueous coating material containing an aqueous resin obtained by dispersing or dissolving a composite resin composed of polysiloxane and an aggregate other than the polysiloxane in an aqueous medium. .

  On the other hand, in reinforced concrete structures such as bridges, tunnels, retaining walls, waterways, water tanks, seawater reservoirs, quay walls, etc., the concrete is highly alkaline (pH 12-13), and a dense passive film is formed on the surface of the reinforcing bars. Therefore, it is generally assumed that rust does not occur. Recently, however, there has been a problem that the concrete is neutralized by acid rain or acid factors such as carbon dioxide in the air or salt damage such as seawater. For example, when concrete becomes neutral and water and oxygen penetrate, the steel bars corrode. As one of the measures to neutralize this reinforced concrete, a protective coating is applied to the concrete surface. For example, the protective coating described in Patent Document 2 is formed by adhering a sheet material made of a nonwoven fabric impregnated with a catalyst compound having a crystal forming action of inorganic cement to an uncured concrete surface that has been placed. . As a result, the catalyst compound is dissolved from the nonwoven fabric by the heat of hydration reaction of the uncured concrete and penetrates into the concrete. The catalyst compound that has penetrated into the concrete diffuses and permanently produces cement crystals, which can prevent deterioration of the concrete.

By the way, the phenomenon that concrete becomes neutral is that calcium hydroxide (CaOH ₂ ) generated by hydration of cement in the concrete is gradually converted to calcium carbonate (CaCO ₃ ) under the action of carbon dioxide in the air. It is said that it gradually loses alkalinity from the surface and becomes neutralized (carbonated). In addition, chloride ions Cl ⁻ derived from snow melting agent sprayed on seawater and roads penetrates into the porous concrete, destroys the passive layer that is formed by the alkalinity of the concrete and protects the surface of the reinforcing bars. However, “salt damage” that causes corrosion in spite of being in an alkaline environment is also a serious problem. However, it is considered impossible to remove chloride ions once infiltrated into the reinforced concrete.

  On the other hand, when the reinforced concrete is neutralized and the rust of the reinforcing bars progresses, the strength decreases, and the reinforcing bars may expand due to rust, leading to cracks in the concrete. As a method for preventing rusting of reinforcing bars, it is widely known to perform anticorrosion by electrochemical reaction (Patent Document 3). In other words, reinforcing bars are used as cathodes, anodes are provided on the outer surface of reinforced concrete, and currents are passed between these electrodes to maintain the potential of the reinforcing bars in the inactive region of steel corrosion, thereby preventing corrosion of the reinforcing bars. . In particular, in Patent Document 3, a metal wire serving as an anode is provided on the surface of reinforced concrete, and the metal wire serving as the anode is connected to the surface of the reinforced concrete using an aqueous conductive paint mixed with conductive particles. It has been proposed. It is described that the water-based conductive paint is produced by mixing water-based acrylic resin or water-based epoxy resin with conductive particles such as petroleum coke particles, graphite pieces, and carbon black particles.

Japanese Patent Application Laid-Open No. 2012-232828 JP 2010-242300 A JP 2012-036343 A

  The paint formed by dissolving the composite resin described in Patent Document 1 in a solvent has a certain effect on weather resistance such as exposure contamination resistance, acid rain resistance, and water resistance as an exterior paint for inorganic material buildings. It is recognized that there is. However, it seems that there is room for improvement in weather resistance and the like as an exterior paint for protecting deterioration of the exterior of a general inorganic material building.

  On the other hand, the protective film described in Patent Document 2 is obtained by adhering a sheet material made of a nonwoven fabric impregnated with a catalyst compound having a crystal forming action of an inorganic cement to an uncured concrete surface on which the concrete is placed. Although it is recognized that neutralization can be prevented, there is room for improvement in workability.

  Furthermore, the protective film described in Patent Document 3 can be applied to the electric protection of reinforced concrete to suppress neutralization and prevent rusting of the reinforcing bars. However, the conductive coating formed by a water-based conductive coating that coats the outer surface of a reinforced concrete building with a metal wire that serves as an anode for cathodic protection is simply a physical bond between the conductive particles and the coating resin. is there. Therefore, there is a problem that the water resistance and weather resistance of the coating film are easily deteriorated when exposed to wind and rain or ultraviolet rays.

  The protective coating for corrosion protection of reinforced concrete has electrical conductivity, air permeability and water permeability, and it is desirable to use it as an anode. However, the paints described in Patent Documents 1 and 2 correspond to the demand. I can't.

The first problem to be solved by the present invention is to provide an exterior paint capable of further improving the weather resistance of the exterior paint film of an inorganic material-based building.
In addition, the second problem is to provide an exterior paint capable of forming an anode coating having conductivity, air permeability and water permeability for reinforced concrete cathodic protection.
Furthermore, the third problem is to provide an anode coating suitable for reinforced concrete cathodic protection in addition to the second problem.

  In order to solve the first problem, the coating material for exterior of the inorganic material building of the present invention (first aspect) is PTFE in which the main component is graft-polymerized with sulfonic acid, and the sulfonic acid equivalent in the main component Is 921 or more, and the main component is mixed with a solvent containing water in the range of 1% by mass or more and 10% by mass or less, preferably in the range of 1.5% by mass or more and 8% by mass or less. And

  As for the sulfonic acid graft polymerization type PTFE (polytetrafluoroethylene) resin which is the main component of the coating material of the first aspect of the present invention, it is known that the main chain PTFE is an electrochemically stable resin. Therefore, since it has characteristics such as contamination by dust in the air, acidic factors such as acid rain or carbon dioxide in the air, deterioration due to sunlight, etc., excellent water resistance and weather resistance, etc. Suitable for protection of exterior wall materials or roofing materials.

  Here, the sulfonic acid equivalent at the end of the graft portion is a numerical value represented by the resin solid weight of the main component per mole of sulfonic acid. That is, when the numerical value is large, there are few sulfonic acid groups, and when the numerical value is small, there are many sulfonic acid groups. On the other hand, since the sulfonic acid group has hydrophilicity, the sulfonic acid equivalent is large (the number of sulfonic acid groups is small) and the water resistance (property that does not dissolve in water) is improved. Conversely, when the sulfonic acid equivalent is small (the number of sulfonic acid groups is large), the water resistance is lowered. Therefore, it is preferable that a general inorganic material-based exterior coating has a sulfonic acid equivalent in the main component of 800 or more in consideration of water resistance.

  In addition, since the sulfonic acid group exhibits (responsible) ionic conductivity, when used as the anode coating of the reinforced concrete of the present invention described later, it is preferable that the sulfonic acid equivalent is small and the number of sulfonic acid groups is large. It is preferable to select the sulfonic acid equivalent according to the conditions.

  According to the exterior paint of the present invention having such a configuration (first aspect), it is applied to the outer surface of a concrete building or the outer surface of a new building material made of an inorganic material and dried, thereby providing water resistance and A coating film excellent in weather resistance can be produced. In particular, the mixing ratio of the main component in the exterior paint containing the solvent may be selected in the range of 1% by mass or more and 10% by mass or less. Furthermore, even within this range, for example, if a range of more than 1.5% by mass and 8% by mass or less is selected, acidic factors such as acid rain or carbon dioxide gas are blocked by the coating film, making it difficult to penetrate and water resistance. And weather resistance can be improved and deterioration by sunlight can be reduced. Further, even if dust in the air adheres, a special effect is obtained in that the exterior surface is cleaned and cleaned every time it rains. Moreover, it is desirable that the exterior coating material of the first aspect is directly applied to the outer surface of a concrete building or a base material of a new building material made of an inorganic material. This simplifies the construction and is effective in shortening the construction period. However, the present invention is not limited to this, and depending on the state of the coated surface of the exterior material, other general undercoating and intermediate coating may be performed, and the exterior coating of the first aspect may be used as the top coating.

  In order to solve the second problem, the exterior coating for reinforced concrete cathodic protection (second aspect) of the present invention differs from the exterior paint of the first aspect in that it defines the upper limit of the sulfonic acid equivalent, Reduce the proportion of ingredients in the exterior paint. That is, the exterior coating material for cathodic protection has a sulfonic acid equivalent in the main component in the range of 800 to 1170, and the mixing ratio of the main component in the exterior coating containing the solvent is 1% by mass or more and 10% by mass. % Or less, preferably 2% by mass or more and 4% by mass or less.

  According to such an exterior paint (second aspect) of the present invention, since the sulfonic acid group in the main component has ionic conductivity, a conductive film can be formed on the surface of the reinforced concrete building. . In particular, a coating film for reinforced concrete cathodic protection functions as an anode, so that it is desirable to have conductivity and sufficiently reduce the surface resistance of the film. Therefore, if the sulfonic acid equivalent responsible for the conductivity of the paint film is too large, the surface resistance becomes too high, so the upper limit is limited to 1170 or less.

  Moreover, the coating film for cathodic protection needs to penetrate the depth of the reinforcing bar with moisture that serves as a channel for the anticorrosion current. Therefore, the mixing ratio of the main component in the exterior paint including the solvent is set to a range lower than that of the exterior paint of the first aspect. Thereby, the density of a coating film can be lowered | hung and air permeability and water permeability can be given. In addition, since concrete is porous, it is possible to form a current path that penetrates from the coating film for anticorrosion to the reinforcing bar. As a result, the anticorrosive current of the reinforcing bars can be passed, and chloride ions, which are the main cause of salt damage of concrete, can be attracted to the vicinity of the coating film by electrophoresis.

  Thus, the coating film formed by depositing the exterior paint (second aspect) of the present invention on the surface of reinforced concrete has conductivity, air permeability, and water permeability, and therefore is suitable as an anode for cathodic protection. A simple anode coating can be formed. Further, this anode coating has an effect that water resistance and weather resistance are hardly deteriorated even when exposed to wind and rain or ultraviolet rays, unlike an anode coating in which conductive particles and a coating resin are physically bonded as in the prior art. In particular, the exterior paint (second aspect) of the present invention is applied directly to the outer surface of reinforced concrete by spraying or coating. Thereby, the anode film suitable for the cathodic protection which suppresses the rusting of the reinforcing steel of a reinforced concrete can be formed.

  According to the anode coating for reinforced concrete cathodic protection of the present invention as described above, water containing acid rain, seawater, or salt and other chlorine compounds (for example, sodium chloride, calcium chloride, etc.) is a reinforcing bar that is a cathode. Penetrates and is broken down by electrochemical reaction. As a result, the alkalinity of the concrete is restored and maintained, and the passive film on the reinforcing bar surface is not affected. On the other hand, negative ions such as chlorine ions decomposed by the electrochemical reaction migrate toward the anode and reach the anode, where they are oxidized into a gas such as chlorine gas, and enter the atmosphere through the pores of the conductive coating. Dissipated. As a result, the special effect of being able to remove chlorine compounds in reinforced concrete, which has been a problem in the past, is obtained.

  The anode coating for reinforced concrete cathodic protection according to the present invention is used by being connected to an anode power source. Therefore, in order to solve the third problem, it is preferable that the surface of the anode coating is provided with an anode electrode made of a string-like or linear carbon fiber or a known platinum group-coated titanium material. In particular, an anode electrode in which a titanium material is formed in a thin strip shape is preferably used. In this case, the electrical connection of the conductor to the anode coating may be made, for example, by pressing with a general conductive adhesive or sealing material. It works even by simply crimping the anode coating. Thereby, the connection to the anode coating of the DC power source for cathodic protection can be easily and reliably performed.

  Furthermore, it is preferable to use a solar cell as a direct current power source for supplying an anticorrosion current. That is, the anode of the solar cell is electrically connected to the anode electrode, and the cathode of the solar cell is electrically connected to the reinforced concrete reinforcing bar. That is, since the current for cathodic protection is a minute current and the voltage is also a DC voltage of several volts to several tens of volts, it is possible to cover a reinforced concrete surface of a large area with a small solar cell. Moreover, what is necessary is just to adjust an electric current so that the electric potential of a reinforcing bar may fall to the well-known inactive area | region of steel corrosion according to the principle of the anticorrosion of a reinforcing bar. Thereby, the iron content of the reinforcing bar is suppressed or prevented from being ionized and eluted, and corrosion of the steel is prevented. The output current of the solar cell is adjusted so that the current flowing at this time maintains the potential of the reinforcing bar in the inactive region.

In addition, in the case of nighttime when rain cannot be obtained or in the case of rain, an anticorrosion current cannot be obtained. However, even with an intermittent anticorrosive current, a certain anticorrosive effect is obtained and chloride ions are removed, so that there is no problem. Moreover, since the OH ⁻ group generated by the electric power of the solar cell remains in the reinforced concrete during the time when sunshine is obtained, the alkalinity around the reinforcing bar is maintained, so that corrosion of the reinforcing bar can be prevented. If necessary, a rechargeable battery having a capacity according to need may be attached.

ADVANTAGE OF THE INVENTION According to this invention, the exterior coating material which can further improve the weather resistance of the exterior coating film of an inorganic material type | system | group building can be provided.
In addition to this, it is possible to provide an exterior coating material capable of forming an anode coating having electrical conductivity, air permeability and water permeability for reinforced concrete cathodic protection.
Furthermore, an anode coating suitable for reinforced concrete cathodic protection can be provided.

1 is a cross-sectional view of a reinforced concrete including an anode coating and an anode electrode formed by an exterior paint for reinforced concrete cathodic protection according to the present invention.

  Hereinafter, the present invention will be described based on examples.

  Example 1 of the exterior paint of the present invention describes an exterior paint for an inorganic material building. The present embodiment is an exterior paint suitable for outer wall materials, roof materials, and the like of various buildings such as ordinary houses, high-rise houses, office buildings, and factory buildings. The outer walls or roofs of these buildings are exposed to dust from the air, acid factors such as acid rain or carbon dioxide in the air, and sunlight. These outer walls or roofs are formed of various materials, but more and more are formed using inorganic materials such as concrete and new building materials made of inorganic materials. These inorganic material-based outer wall materials or roof materials (hereinafter collectively referred to as exterior materials) are widely used because they have a certain weather resistance.

  However, even in inorganic material buildings, exterior materials can deteriorate for a long time when exposed to pollution from air dust, acidic factors such as acid rain or carbon dioxide in the air, sunlight, etc. Are known. In order to suppress such deterioration, a protective film is formed on the surface of the exterior material by painting or the like. However, there is room for improvement in the lifetime and cost of the weather resistance of the exterior paint that protects the deterioration of the exterior of a general inorganic material building.

  The exterior paint for inorganic material buildings of Example 1 of the present invention protects the deterioration of the exterior of general inorganic material buildings, and is a sulfonic acid graft polymerization type PTFE having a chemical structure shown in Chemical Formula 1 ( (Polytetrafluoroethylene) resin as a main component. The RF in Chemical Formula 1 can be variously modified as shown in Chemical Formulas 2-4.

  The main component shown in Chemical Formula 1 is dissolved or mixed in a solvent containing water and alcohol to obtain an exterior paint for an inorganic material building. It is preferable that the exterior coating material of this embodiment is directly applied to the surface of the exterior material by spraying or brushing. Thereby, construction becomes simple and the construction period can be shortened. However, the present invention is not limited to this, and depending on the condition of the surface of the exterior material, for example, when the surface is rough and the permeability of the paint is high, such as concrete, the undercoat and the intermediate coat are appropriately applied, and then this implementation is performed. It does not preclude overcoating the example exterior paint. Further, the undercoat paint and the intermediate coat paint can be appropriately selected according to the purpose.

  PTFE, which is the main chain of the chemical structure of Chemical Formula 1, is known to be an electrochemically stable resin. Therefore, it is difficult to be deteriorated by acid factors such as acid rain or carbon dioxide in the air, sunlight or the like. In addition, because it is excellent in water resistance and weather resistance, it can be easily cleaned by washing against contamination by dust in the air, and it is suitable for protection of inorganic material outer wall materials or roof materials. Yes.

  Here, the sulfonic acid equivalent at the terminal of the graft portion is a numerical value represented by the weight of the solid resin main component per mole of sulfonic acid, that is, the weight of the sulfonic acid graft polymerization type PTFE. Therefore, a large sulfonic acid equivalent value means that there are few sulfonic acid groups, and a small value means that there are many sulfonic acid groups. By the way, since the sulfonic acid group has hydrophilicity, the sulfonic acid equivalent is large (the number of sulfonic acid groups is small) and the water resistance (property that does not dissolve in water) is improved. Conversely, when the sulfonic acid equivalent is small (the number of sulfonic acid groups is large), the water resistance is lowered. Therefore, it is necessary to adjust the sulfonic acid equivalent according to the purpose of use of the exterior paint.

  The inorganic material-type exterior material, which is an application of the exterior paint of the present embodiment, is exposed to wind and rain, so water resistance is the main factor. Therefore, it is preferable that the inorganic material-based exterior coating material of this example has a sulfonic acid equivalent in the main component of a certain value or more in consideration of water resistance. Therefore, as shown in Table 1, a plurality of samples were measured by changing the sulfonic acid equivalent Ew in the main component.

Here, as a method for measuring the sulfonic acid equivalent Ew, there is a method of preparing a calibration curve related to S by FT-IR or atomic absorption method, but the measurement in Table 1 is the simplest and most accurate acid / base titration method. I did. For convenience, a fluorine-based cation exchange resin shown in Chemical formula 5 was used as a sample. This resin is widely used as a solid electrolyte of a fuel cell or as a diaphragm for a salt electric field because of its high electrochemical stability and high ionic conductivity. In particular, it chemical and electrochemical stability, which is responsible chemical structure portion Ruishi the PTFE of the main chain, ionic conductivity grafts terminal sulfonic acid groups SO ₃ ^- since it is responsible, backbone It is understood that evaluation of water resistance and ionic conductivity of the sulfonic acid equivalent can be considered even when PTFE is PTFE or PTDF.

Here, the procedure for measuring the sulfonic acid equivalent by titration of the sample E2 of the fluorinated cation exchange resin will be described below.
-Sample E2 is a 1 propanol / water mixed solution with a non-volatile content of 20%.-Sample E2: Add 100 g of water to 80 g to make 100 g, add 10 g of 1% phenolphthalein solution, and add 1.0 M lithium hydroxide aqueous solution. Dropping ・ Neutralization was confirmed when 4.8 g of 1.0 M lithium hydroxide aqueous solution was dropped. Based on the data obtained by this dropping, the sulfonic acid equivalent Ew was calculated by the following formula (Formula 1).

(Equation 1)
25 × 0.24 / x = y × 1.0 / 1000
Where x is the sulfonic acid equivalent Ew of sample E2.
y is the amount of dripping lithium hydroxide aqueous solution [g]
By substituting y = 4.8 into Equation 1, x = 1042 was obtained.

  From the consideration of Table 1, the sulfonic acid equivalent that allows water resistance is 800. Therefore, by setting the sulfonic acid equivalent in the main component to 800 or more, it is excellent in water resistance and weather resistance if it is applied to the outer surface of a concrete building or the outer surface of a new building material made of an inorganic material and dried. A coated film can be produced.

  On the other hand, in order to ensure the weather resistance, not only the sulfonic acid equivalent, but also the property of blocking the penetration of acid rain and carbon dioxide in the air is required. Therefore, since a high density (denseness) of the resin forming the exterior coating film is required, the mixing ratio of the main component in the exterior coating containing the solvent is increased to a range of 1% by mass or more and 10% by mass or less. If it is set within the range of the mixing ratio (for example, 1.5% by mass or more and 8% by mass or less), dust in the air adheres, and acid factors such as acid rain or carbon dioxide gas are blocked by the coating film and penetrated. It is difficult to improve the water resistance and weather resistance, and the deterioration due to sunlight can be reduced. In addition, every time it rains, the exterior surface is washed with rain, and the adhering dust is washed away to make it clean.

  The durability can be improved by adding the amount of the photocatalyst particles selected from the range of 0.2% by mass or more and 5.0% by mass or less to the coating material mass in the exterior coating material of Example 1.

  Example 2 is an exterior coating for reinforced concrete cathodic protection according to the present invention that solves the second problem. The difference from the exterior paint of Example 1 is that the upper limit of the sulfonic acid equivalent in the main component is defined and the mixing ratio of the main component in the exterior paint is defined in a small range. That is, the exterior coating material for cathodic protection has a sulfonic acid equivalent in the main component in the range of 800 to 1170, and the mixing ratio of the main component in the exterior coating containing the solvent is 1% by mass or more and 10% by mass. % Or less, preferably 2% by mass or more and 4% by mass or less. Since the other points are the same as those of the first embodiment, description thereof is omitted.

  According to this example, since the sulfonic acid group in the main component has ionic conductivity, a conductive coating can be formed on the surface of the reinforced concrete building. In particular, a coating film for reinforced concrete cathodic protection functions as an anode, so that it is desirable to have conductivity and sufficiently reduce the surface resistance of the film. Therefore, if the sulfonic acid equivalent responsible for the conductivity of the paint film is too large, the surface resistance becomes too high, so the upper limit is limited to 1170 or less.

Moreover, the coating film for cathodic protection needs to penetrate moisture to the depth of the reinforcing bar. Therefore, in this embodiment, the mixing ratio of the main component in the exterior paint containing the solvent is set to a range lower than that of the exterior paint of Example 1. Thereby, the coating film can be provided with air permeability and water permeability, and a current path penetrating from the coating film for anticorrosion to the reinforcing bar through the porous concrete layer can be formed. For water permeability, the penetration depth of water is, for example, 5 mm, and the coating amount in that case is 50 to 90 g / m ² . As a result, the anticorrosive current of the reinforcing bars can be passed, and chloride ions, which are the main cause of the neutralization of concrete, can be attracted to the vicinity of the coating film by electrophoresis. Chloride ions attracted to the vicinity of the coating film are neutralized and protonated by protons supplied from the connected anode, and are released to the atmosphere through the coating film having air permeability. As a result, chloride ions in reinforced concrete can be released to the atmosphere and removed.

  As described above, according to the exterior paint of this example, the coating film formed on the surface of the reinforced concrete has conductivity, air permeability, and water permeability, so that an anode film suitable as an anode for cathodic protection is formed. can do. Further, this anode coating has an effect that water resistance and weather resistance are hardly deteriorated even when exposed to wind and rain or ultraviolet rays, unlike an anode coating in which conductive particles and a coating resin are physically bonded as in the prior art. In addition, since a transparent film is formed, there is an advantage that the appearance is not impaired. In particular, the exterior coating of the present embodiment can be directly applied to the outer surface of the reinforced concrete directly by spraying or coating to form a conductive film suitable for the electric protection of the reinforced concrete reinforcing bars.

  By connecting the anode of the DC power source to the conductive coating for reinforced concrete cathodic protection of the present embodiment formed in this way, and connecting the cathode to the reinforcing bar to flow the corrosion protection current, acid rain, seawater, or salt content , And other chlorine compounds (for example, sodium chloride, hydrogen chloride, etc.) penetrate into the cathode rebar and are decomposed by an electrochemical reaction. As a result, the alkalinity of the concrete is maintained and the passive film on the surface of the reinforcing bar is not affected. On the other hand, negative ions such as chlorine ions decomposed by the electrochemical reaction migrate toward the anode and reach the anode, where they are oxidized into a gas such as chlorine gas, and enter the atmosphere through the pores of the conductive coating. Dissipated. As a result, the special effect of being able to remove chlorine compounds in reinforced concrete, which has been a problem in the past, is obtained.

  By including the amount of the photocatalyst particles selected from the range of 0.2% by mass or more and 5.0% by mass or less with respect to the coating mass in the exterior coating of Example 2, the hydrophilic state and the high conductivity due thereto are obtained. Can be improved.

  Example 3 of the present invention uses an electrically conductive coating for reinforced concrete cathodic protection formed using the exterior paint of Example 2, and has an anode coating having a structure connectable to a DC power source, and an anticorrosion current connected to the DC power source. An anode coating having a structure capable of flowing through is formed. In particular, the anode coating must be connected to the anode of the DC power source. However, since a conductive film formed of paint is generally very thin, the structure or structure of the anode electrode on the film side, which is an interface for connecting the film and the anode of the DC power supply, is important. Conventionally, a rectangular plate-like anode electrode is embedded in an anode coating or attached with a conductive adhesive or the like, and an electric wire connected to the anode of a DC power source is terminal-connected to the anode electrode. According to this, since it is necessary to disperse a plurality of rectangular plate-like anode electrodes on the anode coating as appropriate, the work becomes complicated, and wiring is required for them, which causes problems in workability. There is.

  This embodiment is characterized in that the anode electrode for connecting the anode coating and the anode of the DC power source is improved. In FIG. 1, the structure of the anode coating, anode electrode, and DC power supply for reinforced concrete cathodic protection of a present Example is shown with sectional drawing. FIG. 1 schematically shows a partial cross-section of reinforced concrete, and the dimensions of each part are described in an appropriately reduced scale, so that they are different from actual dimensions. As shown, the reinforced concrete 1 has a reinforcing bar 2 embedded therein. A conductive coating that is the anode coating 3 is formed on the outer surface of the reinforced concrete 1. On the surface of the anode coating 3, a string-like anode electrode 4 made of carbon fiber is fixed by crimping with a conductive adhesive 5 and electrically connected thereto. In addition, it may replace with the adhesive material 5 and you may make it press-contact with a well-known sealing material.

  For example, a rectangular electrode terminal 6 is provided at an appropriate position of the anode electrode 4 so as to be electrically connected to the string-like anode electrode 4. The electrode terminal 6 is fixed by a conductive adhesive (not shown). The electrode terminal 6 is connected to the anode of the DC power source 7 through a connection terminal and an electric wire (not shown). The cathode of the DC power source 7 is connected to the reinforcing bar 2 through an electric wire. Further, the string-like anode electrodes 4 do not need to be formed in a net shape, and the intervals between the anode electrodes 4 that are stretched and arranged in a string shape or a line shape may be sparse (20 cm to 1000 cm intervals, preferably 30 to 50 cm intervals). In addition, it is preferable to close the interval because gasification of chlorine ions is promoted.

  According to the present embodiment, since the anode coating 3 of the reinforced concrete 1 has water permeability, water containing acid rain, seawater, salinity, and other chlorine compounds (for example, sodium chloride, hydrogen chloride, etc.) is present. It penetrates into the inside of the reinforced concrete 1 through the anode coating 3 and reaches the reinforcing bar 2 which is a cathode. In the process, an anticorrosion current flows from the DC power source 7 to the rebar 2 through the electrode terminal 6 and the anode electrode 4, and acid rain, seawater, salinity, and other chlorine compounds (for example, sodium chloride, calcium chloride, etc.) Is decomposed by electrochemical reaction. As a result, the alkalinity of the reinforced concrete 1 is maintained, the passive film on the surface of the reinforcing bar 2 is not attacked, the alkalinity of the concrete is maintained, and the passive film on the surface of the reinforcing bar is not attacked, that is, the elution of iron ions is suppressed. Thus, rusting of the reinforcing bars 2 is suppressed.

  On the other hand, negative ions such as chloride ions generated by electrolysis migrate toward the anode and reach the anode, where they are oxidized into a gas such as chlorine gas, and are diffused into the atmosphere through the pores of the anode coating 3. Is done. As a result, the chlorine compound in the reinforced concrete, which has been a problem in the past, can be removed, and the special effect that the corrosion protection of the reinforcing bars can be maintained is obtained. In addition to this, it goes without saying that the paint film of Example 2 has the weather resistance.

  Here, the DC power source 7 of the present embodiment is preferably configured using a solar cell or a wind power generator. That is, it is assumed that the anode coating 3 in which the anode of the solar cell is electrically connected and the cathode of the solar cell are electrically connected to the reinforcing bar 2. That is, since the anticorrosion current of the reinforcing bars is a minute current and the voltage is also a DC voltage of several volts to several tens of volts, the surface of the reinforced concrete 1 having a large area can be covered with a small solar cell. In particular, the principle of the anticorrosion of the reinforcing bars 2 is to adjust the current so that the potential of the reinforcing bars 2 is lowered to a known inactive region of steel corrosion. Thereby, the iron content of the reinforcing bar 2 is suppressed or prevented from being ionized and eluted, and corrosion of the steel is prevented. In order to adjust the output current of the solar cell in order to maintain the potential of the reinforcing bar 2 in the inactive region, the DC power supply 7 is configured to have a voltage control function for controlling the anticorrosion current to the set current.

  Moreover, when a solar cell is used, the anticorrosion current cannot be obtained at night or when it is raining when sunshine is not obtained. However, even with an intermittent anticorrosive current, a certain anticorrosive effect is obtained and chloride ions are removed, so that there is no problem. If necessary, a storage battery having an appropriate capacity may be attached.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited thereto, and can be implemented in a form that is modified or changed within the scope of the gist of the present invention. It will be apparent to those skilled in the art that such variations or modifications are naturally within the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Reinforced concrete 2 Reinforcement 3 Anode coating 4 Anode electrode 5 Adhesive 6 Electrode terminal 7 DC power supply

Claims (7)

  The main component is PTFE obtained by graft polymerization of sulfonic acid, the sulfonic acid equivalent in the main component is 921 or more, the main component is in the range of 1% by mass to 10% by mass, or 1.5% by mass or more. An exterior paint for an inorganic material-based building mixed with a solvent containing water in the range of 8% by mass or less.   The exterior paint according to claim 1, further comprising photocatalyst particles in a range of 0.2 mass% or more and 6.0 mass% or less.   The main component is PTFE obtained by graft polymerization of sulfonic acid, the sulfonic acid equivalent in the main component is in the range of 800 to 1170, and the main component is in the range of 1% by mass to 10% by mass, preferably An exterior paint for reinforced concrete, which is mixed with a solvent containing water in the range of 2% by mass or more and 4% by mass or less.   The exterior paint according to claim 3, further comprising photocatalyst particles in a range of 0.2 mass% to 5.0 mass%.   An anode coating for reinforced concrete cathodic protection having electrical conductivity and air permeability formed by applying the exterior paint according to claim 3 or 5 to the outer surface of a reinforced concrete building.   Furthermore, the anode coating is provided with an anode electrode formed by fixing a strip-like, string-like, or wire-like conducting wire formed of titanium metal coated with carbon fiber or platinum group metal oxide on the surface of the anode coating. The anode coating according to claim 5. The anode coating according to claim 6, wherein the anode of the solar cell is electrically connected to the anode electrode, and the cathode of the solar cell is electrically connected to the reinforcing bar of the reinforced concrete.

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