JP2019143187A - Rust conversion method - Google Patents

Abstract

To provide a rust conversion method having high antirust effect, in a steel stock existing in a place affected greatly by seawater or UV light.SOLUTION: There is provided a rust conversion method for converting red rust into black rust, in a red rust steel stock having a red rust layer on the surface of the steel stock made of iron or mainly composed of iron. The rust conversion method includes a penetration step for penetrating a liquid rust conversion agent having action for converting red rust into black rust, to the inside the red rust layer, and a rust conversion step for converting red rust in the red rust layer into black rust by the penetrated rust conversion agent under a sea wind atmosphere.SELECTED DRAWING: None

Description

  The present invention relates to a rust conversion method and a rust conversion agent.

  Steel materials including iron are widely used as constituent materials for various structures, but rust is likely to occur. When the steel material rusts, not only the appearance is impaired, but also the strength of the structure may be impaired. Therefore, various rust prevention methods for suppressing the progress of rust generation in steel materials have been studied.

  Steel materials are usually coated with a top coating, and rust is generated inside the top coating. As such a rust prevention method with steel materials, for example, a coating film of top coating is peeled off, and then a kelen treatment or the like is performed to remove at least a part of the surface rust, and then the progress of rust generation is suppressed. There is known a method of applying (rust preventive agent) and finally performing top coating. As such a method, more specifically, as a rust preventive, it can sufficiently penetrate into the rust surface of steel materials and can be cured in a short time, and as a result, can be overcoated in a short time. A repair coating method for steel structures used is disclosed (see Patent Document 1). According to this method, it is said that the anticorrosion coating film excellent in anticorrosion property can be formed in a short time.

JP 2016-34621 A

  On the other hand, rust is particularly likely to occur in places where the influence of seawater and ultraviolet rays is large, such as on the sea or on the shore near land, even on land. On the other hand, in the rust prevention method disclosed in Patent Document 1, it is not certain that a sufficient rust prevention effect can be obtained in the steel material in such a place.

  Then, this invention makes it a subject to provide the rust prevention method with a high rust prevention effect in the steel materials which exist in the place where the influence of seawater and an ultraviolet-ray is large.

The present invention is a rust conversion method for converting the red rust to black rust in a red rust steel material having a red rust layer on the surface of a steel material mainly composed of iron or iron, and has an action of converting red rust to black rust. A permeation step for infiltrating the liquid rust conversion agent into the red rust layer; and a rust conversion step for converting red rust in the red rust layer to black rust by the permeated rust conversion agent in a sea breeze atmosphere; A rust conversion method is provided.
In the rust conversion method of the present invention, it is preferable that in the infiltration step, the rust conversion agent is infiltrated into a boundary region between the steel material mainly made of iron or iron and the red rust layer.
In the rust conversion method of the present invention, it is preferable that the red rust layer is not subjected to the kelen treatment or the keren three-type treatment is performed before the infiltration step.

In the rust conversion method of the present invention, the rust conversion agent may contain a polyhydric phenol compound as an active ingredient, the polyhydric phenol compound, a resin other than the polyhydric phenol compound, and an organic solvent. preferable.
In the rust conversion method of the present invention, the content of the polyphenol compound in the rust conversion agent is 0.5 to 5% by mass, the content of the resin is 1 to 10% by mass, and the organic It is preferable that content of a solvent is 85-98.5 mass%.
Moreover, this invention is a rust conversion agent which has the effect | action which converts red rust into black rust and which has a polyhydric phenol compound as an active ingredient, Comprising: Content of the said polyhydric phenol compound of the said rust conversion agent is 0. 5-5% by mass, the content of the resin other than the polyhydric phenol compound is 1-10% by mass, the content of the organic solvent is 85-98.5% by mass, and the total amount of the organic solvents The ratio of the content of toluene to the content is 27 to 37% by mass, the ratio of the content of cyclohexanone is 17 to 27% by mass, the ratio of the content of methyl ethyl ketone is 5 to 15% by mass, The proportion of isobutyl ketone content is 2 to 8% by mass, the proportion of acetone content is 2 to 8% by mass, the proportion of ethylene glycol monobutyl ether content is 2 to 8% by mass, 2 - The proportion of the content of panol, 1-butanol, 2-methyl-1-propanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, butyl acetate, 3-methoxybutyl acetate and kerosene is less than 1% by mass, respectively. Provide rust conversion agent.

  ADVANTAGE OF THE INVENTION According to this invention, the rust prevention method with a high rust prevention effect is provided in the steel materials which exist in the place where the influence of seawater and an ultraviolet-ray is large.

It is an imaging data in the test piece (T1) to which the rust conversion agent is not applied in Example 1 and the test piece (T2) to which the rust conversion agent is applied. It is imaging data of piping on the ship which will apply these before applying a rust conversion agent (L1) or a rust preventive agent in Example 2. It is the imaging data before time-lapse | temporary of the piping on the ship which applied the rust conversion agent (L1) or the rust preventive agent in Example 2. FIG. It is the imaging data after time-lapse | temporary of the piping on the ship which applied the rust conversion agent (L1) or the rust preventive agent in Example 2. FIG. In Example 2, it is the imaging data of the pipe | tube in a different angle acquired simultaneously at the time of acquisition of the imaging data shown in FIG. In Example 2, when acquiring the imaging data shown in FIG. 4, it is the imaging data of the piping at a higher magnification at different angles, acquired at the same time. It is the imaging data of the structure on a ship to which the rust conversion agent in Example 3 is applied, (a) is imaging data before aging, (b) is imaging data after aging. In Example 3, it is the imaging data of the structure on a ship to which the rust preventive agent is applied, (a) is imaging data before aging, (b) is imaging data after aging.

<< Rust conversion method >>
The rust conversion method of this embodiment is a rust conversion method for converting the red rust to black rust in a red rust steel material having a red rust layer on the surface of a steel material made of iron or iron as a main component. A red rust in the red rust layer is converted to black rust by the permeation step of infiltrating the inside of the red rust layer with a liquid rust conversion agent having a converting action and the permeated rust conversion agent in a sea air atmosphere. And a rust conversion step.

According to the rust conversion method, a sufficient rust prevention effect that sufficiently suppresses the progress of rust generation in steel materials existing in places where the influence of seawater and ultraviolet rays is large, such as on the sea and on the shore near the sea even on land. Is obtained.
Examples of the application target of the rust conversion method include various structures on the sea or coastal areas, and more specifically, various structures of ships including ship hulls, pipes, tanks, etc .; bridges, etc. Offshore buildings; coastal facilities, buildings, etc., but are not limited to these.

In the presence of water and air, iron ions (Fe ²⁺ ) are generated from iron, and these iron ions pass through ferrous hydroxide (Fe (OH) ₂ ) and are one type of iron oxide, hematite (Fe ₂ O ₃ ). This hematite is also called hematite or ferric oxide and is a kind of red rust.
On the other hand, iron ions (Fe ²⁺ ) and red rust react in the presence of a reducing agent to become magnetite (Fe ₃ O ₄ ). This magnetite is black rust, also called triiron tetroxide or magnetite.

In the rust conversion method, red rust is converted to black rust using a reducing agent (rust conversion agent). That is, the rust conversion method uses iron ions (Fe ²⁺ ), which are a new source of rust, and red rust that has already been generated to generate black rust and suppress further rust generation. To do. In the rust conversion method, the reason for converting red rust to black rust in a sea breeze atmosphere is to use newly generated iron ions (Fe ²⁺ ). Since the rust conversion method is performed in a sea breeze atmosphere as described above, it is particularly applicable to steel materials existing in places where the influence of seawater and ultraviolet rays is large, such as the above-mentioned various structures on the sea or coastal areas. Are better. This is a point completely different from the conventional rust conversion method.
In the present specification, “rust conversion” means conversion of red rust to black rust.

Moreover, in the said rust conversion method, a liquid rust conversion agent is used, this is penetrated into the inside of a red rust layer, and rust conversion is performed. By doing in this way, rust conversion is possible also in the deep part of a red rust layer, and sufficient rust prevention effect is acquired.
The rust conversion agent used in this embodiment will be described in detail later.

The steel material to which the rust conversion method is applied is made of iron or a metal mainly composed of iron, and is a general metal material containing iron that can generate rust. Examples of the metal containing iron as a main component include cast iron.
In the present specification, “mainly containing iron” means that the iron content is 80% by mass or more.

  The red rust steel material only needs to have a red rust layer on the surface of a steel material made of iron or iron as a main component, and the thickness of the red rust layer is not particularly limited.

<Infiltration process>
In the infiltration step, a liquid rust conversion agent having an action of converting red rust into black rust is infiltrated into the red rust layer. When the liquid rust conversion agent penetrates into the red rust layer of the red rust steel material, a sufficient rust prevention effect is obtained in the entire area of the red rust steel material.

[Rust conversion agent]
The rust conversion agent is liquid and has an action of converting red rust to black rust.
It is preferable that a rust conversion agent is liquid at -5-40 degreeC, for example.
The viscosity of the rust conversion agent at 20 ° C. is preferably 0.02 to 0.05 Pa · s, and more preferably 0.025 to 0.04 Pa · s. The rust conversion agent having a viscosity equal to or higher than the lower limit is easier to prepare. When the viscosity of the rust conversion agent is not more than the above upper limit value, the rust conversion agent penetrates more easily into the red rust layer.
The viscosity of the rust conversion agent can be measured using, for example, a rotary viscometer (Krebs viscometer).

(Polyhydric phenol compound)
The rust conversion agent preferably contains a polyhydric phenol compound as an active ingredient having an action of converting red rust to black rust.
The polyhydric phenol compound has one or more benzene ring skeletons, and at least a part or all of the benzene ring skeletons have two or more hydroxyl groups per one.
Examples of the polyhydric phenol compound include tannic acid.

  The polyhydric phenol compound contained in the rust conversion agent may be only one kind, may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof can be arbitrarily selected. .

  When the said rust conversion agent contains the said polyhydric phenol compound, it is preferable that content of the polyhydric phenol compound of a rust conversion agent is 0.5-5 mass%, and is 0.9-2 mass%. It is more preferable.

(resin)
The rust conversion agent preferably contains a resin other than the polyhydric phenol compound.
The resin fills voids in the red rust layer during the rust conversion from red rust to black rust, and the black rust layer after the rust conversion from red rust to black rust, and finally stabilizes the structure of the black rust layer Let
In addition, in this specification, description only with "resin" means the above-mentioned "resins other than a polyhydric phenol compound" unless there is particular notice.

The resin is not particularly limited as long as it is other than the polyhydric phenol compound, and may be curable or non-curable.
Examples of the resin include acrylic resin, epoxy resin, polyurethane, polyvinyl chloride, fluorine resin, acrylic silicon resin, and polyester.

  The said resin which the said rust conversion agent contains may be only 1 type, 2 or more types, and when it is 2 or more types, those combinations and ratios can be selected arbitrarily.

  When the rust conversion agent contains the resin, the content of the resin of the rust conversion agent is preferably 1 to 10% by mass, and more preferably 2 to 5% by mass.

(Organic solvent)
The rust conversion agent preferably contains an organic solvent. The rust conversion agent containing an organic solvent can be more easily penetrated into the red rust layer.
The organic solvent is not particularly limited as long as the effects of the present invention are not impaired.

  Examples of the organic solvent include aromatic hydrocarbons such as toluene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethanol, 2-propanol, 1-butanol, 2-butanol, and 2-methyl-1-propanol. Alcohols such as ethyl acetate, butyl acetate and 3-methoxybutyl acetate; alkylene glycol alkyl ethers such as ethylene glycol monobutyl ether and propylene glycol monomethyl ether; alkylene glycol monoalkyl ether esters such as propylene glycol monomethyl ether acetate; kerosene (Hydrocarbon) and the like.

  The said organic solvent which the said rust conversion agent contains may be only 1 type, may be 2 or more types, and when it is 2 or more types, those combinations and ratios can be selected arbitrarily.

  When the rust conversion agent contains the organic solvent, the content of the organic solvent in the rust conversion agent is preferably 85 to 98.5% by mass, and more preferably 93 to 97.1% by mass. .

The said rust conversion agent can adjust physical properties, such as the viscosity, by adjusting the combination and content of the said organic solvent to contain, and can improve the permeability to the inside of a red rust layer more. .
As a preferable rust conversion agent from such a viewpoint, for example, as the organic solvent, toluene, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, acetone, ethylene glycol monobutyl ether, 2-propanol, 1-butanol, 2-methyl-1- Examples include propanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, butyl acetate, 3-methoxybutyl acetate and kerosene. Thus, by defining the combination of organic solvents, the rust conversion agent is more excellent in penetrability into the red rust layer.

  Furthermore, as a more preferable thing with such a rust conversion agent, the ratio of the content of toluene with respect to the total content of the said organic solvent is 27-37 mass%, and the ratio of the content of cyclohexanone is 17- 27% by mass, the proportion of methyl ethyl ketone content is 5-15% by mass, the proportion of methyl isobutyl ketone content is 2-8% by mass, and the proportion of acetone content is 2-8% by mass. The content ratio of ethylene glycol monobutyl ether is 2 to 8% by mass, 2-propanol, 1-butanol, 2-methyl-1-propanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, butyl acetate , 3-methoxybutyl acetate and kerosene content ratios are each less than 1% by mass There can be listed. Thus, by defining the ratio of the content of each organic solvent listed here relative to the total content of the organic solvent, the rust conversion agent is particularly excellent in penetrating into the red rust layer. It will be a thing. Here, the proportion of the content of the eight organic solvents described above as “less than 1% by mass” can be set independently for each organic solvent. That is, the proportions of the contents of the eight organic solvents may all be the same, all may be different, or only a part may be the same. Moreover, the lower limit of the ratio of the contents of these eight organic solvents is not particularly limited as long as it is greater than 0% by mass.

(Other ingredients)
The rust conversion agent may contain other components that do not correspond to any of the polyhydric phenol compound, the resin, and the organic solvent.
The other components can be arbitrarily selected according to the purpose within a range not impairing the effects of the present invention, and are not particularly limited.

  The said other component which the said rust conversion agent contains may be only 1 type, may be 2 or more types, and when it is 2 or more types, those combinations and ratios can be selected arbitrarily.

The content of the other component of the rust conversion agent is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, and 1% by mass or less. It is particularly preferred that
The lower limit value of the content of the other component of the rust conversion agent is not particularly limited. Content of the said other component of the said rust conversion agent is 0 mass% or more.

The rust conversion agent preferably contains the polyhydric phenol compound, resin and organic solvent.
In such a rust converting agent, it is preferable that one or more selected from the group consisting of the polyhydric phenol compound, the resin, and the organic solvent satisfy the above-described content condition.
Among them, as a more preferable rust conversion agent, for example, the content of the polyhydric phenol compound is 0.5 to 5% by mass, the content of the resin is 1 to 10% by mass, The thing whose content is 85-98.5 mass% is mentioned.
And as a particularly preferable rust conversion agent, for example, the content of the polyhydric phenol compound is 0.5 to 5% by mass, the content of the resin is 1 to 10% by mass, and the content of the organic solvent The amount is 85 to 98.5% by mass, the ratio of the content of toluene to the total content of the organic solvent is 27 to 37% by mass, and the ratio of the content of cyclohexanone is 17 to 27% by mass The proportion of methyl ethyl ketone content is 5 to 15% by mass, the proportion of methyl isobutyl ketone content is 2 to 8% by mass, the proportion of acetone content is 2 to 8% by mass, ethylene glycol The content ratio of monobutyl ether is 2 to 8% by mass, and 2-propanol, 1-butanol, 2-methyl-1-propanol, propylene glycol monomethyl ether, Propylene glycol monomethyl ether acetate, butyl acetate, the ratio of the content of 3-methoxybutyl acetate and kerosene, include those wherein each less than 1% by weight.

  The said rust conversion agent can be manufactured by mix | blending an essential component and an arbitrary component as needed. Here, the “essential component” is an effective component having a rust conversion action such as the polyhydric phenol compound. The “arbitrary component” is, for example, the resin, the organic solvent, other components, and the like.

  The method of mixing the compounding ingredients is not particularly limited, and is a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer, a three-roller, a kneader, a bead mill, etc .; What is necessary is just to select suitably from well-known methods, such as the method of mixing.

The temperature at the time of blending is not particularly limited as long as each blending component does not deteriorate, and may be, for example, 10 to 50 ° C.
The blending time is not particularly limited as long as each blending component does not deteriorate, and may be, for example, 1 to 60 minutes.

  The rust conversion agent can be used in the permeation step as it is after being manufactured by the method as described above. Conventional rust preventives include two-component products that use a mixture of two types of raw materials, but the rust conversion agent is not a two-component product, so the permeation process is simply performed. Can do. That is, the rust conversion method can be performed by a simplified process.

In the infiltration step, it is preferable that the rust conversion agent is infiltrated into a boundary region between the red rust steel material and the red rust layer. Thus, a higher rust prevention effect is acquired by making a rust conversion agent reach | attain to the said boundary area | region.
The said boundary area | region is an area | region used as a boundary of the red rust layer in red rust steel materials, and the layer which does not have red rust adjacent to this.
For example, the rust conversion agent can be more easily reached to the interface by adjusting the physical properties such as the viscosity of the rust conversion agent or the amount used.

The amount of the rust conversion agent used is preferably 100 to 400 g, more preferably 150 to 300 g, per 1 m ² of the surface of the application target portion of the rust conversion agent. That is, it is preferable that the usage-amount of the said rust conversion agent is 100-400 g / m < ² > with respect to the surface of the application target part of a rust conversion agent, and it is more preferable that it is 150-300 g / m < ² >. When the amount of the rust conversion agent used is not less than the lower limit, a higher rust prevention effect can be obtained. The excessive use of a rust conversion agent is suppressed because the usage-amount of a rust conversion agent is below the said upper limit.

  Here, the “applicable part of the rust conversion agent” means “the part of the red rust layer for allowing the rust conversion agent to permeate”. For example, if the surface is rough, such as when the surface of the application target part of the rust conversion agent is floating or part of the red rust has fallen off, As the area value, an area value when the surface is viewed from above and viewed from above may be adopted.

In order to infiltrate the rust conversion agent into the red rust layer, for example, the rust conversion agent may be attached to at least the surface of the red rust layer.
The method for attaching the rust conversion agent to the red rust layer is not particularly limited, and can be appropriately selected in consideration of, for example, the size of the object to which the rust conversion agent is applied.
For example, an application method in which a rust conversion agent is applied by brushing or spraying is suitable as a method for attaching the rust conversion agent regardless of the size of the object to be applied.
For example, an immersion method in which an object to be applied is immersed in a rust conversion agent is suitable as a method for attaching the rust conversion agent when the size of the application object is small.

Conditions such as temperature and atmosphere when performing the infiltration step are not particularly limited. For example, the infiltration step may be performed outdoors or indoors.
When the infiltration step is performed outdoors, it may be performed under a sea breeze atmosphere or under a normal atmosphere that is not under a sea breeze atmosphere. However, in this case, it is preferable to perform the infiltration step under fine weather or cloudy weather (in other words, under non-rainfall conditions) so as not to inhibit the penetration of the rust conversion agent into the red rust layer.
When the infiltration process is performed indoors, the temperature and atmosphere may be set to a specific range or may be performed without setting.

  In this specification, “under the sea breeze atmosphere” means, in other words, an air atmosphere where the presence of sea breeze is recognized. For example, on the sea, coastal areas close to the sea even on land are under a sea breeze atmosphere. It can be said. Focusing on the components, it can be said that the salt concentration per unit volume is higher in the sea breeze atmosphere than in the other atmosphere.

  The infiltration step may be performed a plurality of times. That is, in this embodiment, in the red rust layer not containing the rust conversion agent, an initial penetration step for infiltrating the rust conversion agent, and after the initial penetration step, in the red rust layer containing the rust conversion agent, The rust conversion step may be performed after the osmosis agent is repeatedly infiltrated and the osmosis conversion step is performed once or twice or more.

  The number of times of performing the permeation step may be appropriately selected according to the purpose, but is preferably 1 to 4 times, and more preferably 1 to 3 times. When the number of times is less than or equal to the upper limit value, a sufficient rust prevention effect can be obtained more efficiently.

  When the permeation step is performed twice or more, the methods for performing the permeation step each time may be all the same, all may be different, or only a part may be the same.

  When the permeation step is performed twice or more, the interval between the permeation steps can be arbitrarily set. For example, the time interval until the next infiltration step is performed may be, for example, 20 minutes to 24 hours, 20 minutes to 12 hours, and 20 minutes to 5 hours.

  When the permeation step is performed twice or more, a rust conversion step described later may be performed between the permeation steps. If it is a stage before a rust conversion process is completed, according to the objective, an osmosis | permeation process can be performed arbitrary number of times at arbitrary timings.

The presence or absence of penetration of the rust conversion agent into the red rust layer in the permeation step can be confirmed by observing the adhesion site of the rust conversion agent in the red rust layer. If the liquid residue remains clear at the location (attachment surface) of the rust conversion agent in the red rust layer, the rust conversion agent has not penetrated into the red rust layer, or it has been determined that the penetration is insufficient. it can. On the other hand, when the liquid substance does not remain, it can be determined that the rust conversion agent has sufficiently penetrated into the red rust layer.
As will be described later, when the film of the top coat (top coat film) is formed on the red rust layer, a rust conversion agent is attached to the top coat film. Therefore, if the adhesion site | part of the rust conversion agent of this top coat film is observed similarly to said case, the presence or absence of penetration | invasion of the rust conversion agent to the inside of a red rust layer can be confirmed.

<Rust conversion process>
In the rust conversion step, the red rust in the red rust layer is converted to black rust by the permeated rust conversion agent in a sea breeze atmosphere. By generating black rust by this step, the progress of rust generation is suppressed. Moreover, since the generated black rust layer functions as a protective layer that protects the steel material from sea breeze and ultraviolet rays that cause rust generation, the progress of rust generation is further suppressed.

  The said rust conversion process can be performed by putting the red rust steel material which made the rust conversion agent osmose | permeate the inside of a red rust layer by the said osmosis | permeation process in a sea wind atmosphere. The red rust in contact with the rust conversion agent is converted to black rust with the passage of time in a sea breeze atmosphere. Therefore, if the red rust steel material in which the rust conversion agent has permeated into the red rust layer is aged in a sea breeze atmosphere, the rust conversion step can be performed without any other operation.

  The time for performing the rust conversion step is not particularly limited as long as the rust conversion proceeds sufficiently, and can be appropriately selected in consideration of the environment in which this step is performed, the type of the object to be applied in this step, and the like. Usually, it is preferable that the time which performs a rust conversion process is 60 to 180 days, and it is more preferable that it is 60 to 150 days.

  When a black rust layer is used as a protective layer by a conventional method, the time required for rust conversion from red rust to black rust is usually about one year or longer. Therefore, the time for the rust conversion process is significantly shorter than the conventional required time. That is, the rust conversion method is remarkably excellent in that the effect is achieved in a very short time.

  If the said rust conversion process can be made into a sea breeze atmosphere, it may be performed outdoors, for example, and may be performed indoors.

<Other processes>
The said rust conversion method may have another process in the range which does not impair the effect of this invention other than the said osmosis | permeation process and a rust conversion process.
For example, in the permeation step, the red rust layer that permeates the rust conversion agent into the inside is not subjected to a kelen treatment (for example, see JIS Z 0103) such as removing a part of the surface of the red rust. Although it is good, what carried out such keren processing may be used.

  The kelen processing includes, for example, kelen type 1 processing, kelen type 2 processing, keren type 3 processing, and the like depending on the degree. In these keren treatments, the degree of rust removal is high in the order of kelen type 1 treatment, kelen type 2 treatment, and kelen type 3 treatment. For example, in the one-type treatment of keren, rust is completely removed using an instrument such as sand blast, grit blast, or shot blast. In the Keren type 2 treatment, rust is removed using a tool such as a power tool, a disk sander, or a wire brush. In the Keren 3 type treatment, floating rust is removed using a power tool, a manual tool, or a tool such as a scraper.

In the rust conversion method, it is not necessary to perform any kelen treatment of the red rust layer before the infiltration step (all types of kelen treatment, one type of kelen treatment, two types of kelen treatment, and three types of kelen treatment). Or a mild kelen treatment such as a keren three-type treatment may be performed.
That is, as the rust conversion method, there is a method that does not include a step of performing a kelen treatment of the red rust layer or a step of performing a mild keren treatment of the red rust layer before the infiltration step. In the rust conversion method, since the rust conversion agent has high permeability into the red rust layer, the red rust layer is not subjected to any keren treatment, or the red rust layer is subjected to mild kelen treatment. However, a sufficient antirust effect can be obtained. For example, as a preferable rust conversion method, there is a method in which the red rust layer is not subjected to the kelen treatment or the kelen three-type treatment is performed before the infiltration step.

  The steel material may be coated with a top coat containing a resin component such as an epoxy resin or an acrylic resin (in the present specification, such a steel material may be referred to as “top coat steel material”). In such a top-coated steel material, rust is mainly generated on the inner side of the coating film of the top-coating paint (sometimes referred to as “top-coating film” in this specification). In order to obtain a sufficient rust-preventing effect in such a top-coated steel material, conventionally, a top-coating film peeling process for peeling the top-coating film is performed to expose the red rust layer, and then a rust inhibitor is applied to the red rust layer. It was.

On the other hand, when the rust conversion method is applied to such a top coat steel material, the top coat film peeling step for peeling off the top coat film may or may not be performed before the permeation step. Good.
In other words, examples of the rust conversion method include those having and not having a top coating film peeling step for peeling the top coating film before the infiltration step.
The rust converting agent has high permeability to the top coat film, and when attached to the top coat film, it penetrates the top coat film and easily reaches the red rust layer deeper than the top coat film. Therefore, in the said rust conversion method, sufficient rust prevention effect is acquired even if it does not peel off the top coat film of top coat steel materials.

  The said coating film peeling process can be performed by the method similar to the case of the above-mentioned keren process, for example.

  Moreover, when applying the said rust conversion method to the above-mentioned top coat steel materials, a top coat film is penetrated in the thickness direction in one place or two places or more of the top coat film before the infiltration step. A through hole may be formed. That is, as the rust conversion method, before the infiltration step, a step of forming a through-hole penetrating the top coat film in the thickness direction at one place or two or more places of the top coat film (through hole forming step). ). By forming the through hole in the top coat film, the rust conversion agent can be more easily penetrated into the red rust layer through the top coat film than when the through hole is not formed.

Regardless of the number of times of the permeation step, after the permeation step, for example, a drying step of drying excess rust conversion agent such as a material not permeating the red rust layer may be performed. For example, when the permeation process is performed twice or more, the drying process may be performed between the permeation processes.
The rust conversion agent may be dried by a known method, for example, heat drying or room temperature drying. In the case of room temperature drying, for example, it may be dried under a sea breeze atmosphere, or may be dried under a normal air that is not under a sea breeze atmosphere. In the case of heat drying, the heating temperature may be 40 to 70 ° C., for example, but this is only an example.

In the rust conversion method, after the infiltration step or rust conversion step, a red rust layer, a red rust layer during rust conversion from red rust to black rust, or an upper portion of the black rust layer after rust conversion from red rust to black rust, A top coat film may be formed. That is, as the rust conversion method, after the infiltration step or the rust conversion step, the red rust layer, the red rust layer during the rust conversion from red rust to black rust, or the upper portion of the black rust layer after the rust conversion from red rust to black rust In addition, those having a step of forming a top coat film (top coat film forming step) are mentioned. Thus, a higher rust prevention effect may be acquired by forming a top coat film.
The top coat film can be formed by a known method. For example, a top coating containing a resin component such as an epoxy resin or an acrylic resin is converted into a red rust layer, a red rust layer from red rust to black rust, or from red rust to black rust after the infiltration step or rust conversion step. The top coat film can be formed by coating and drying on the black rust layer after rust conversion.

The amount of the top coating material used is not particularly limited and may be appropriately adjusted in consideration of the type of top coating material. Usually, it is preferable that the usage-amount of top coat is 100-400g per 1m < ² > of the area of the surface of the application target part of top coat. That is, it is preferable that the usage-amount of top coat is 100-400 g / m < ² > with respect to the surface of the application target part of top coat. When the amount of the top coating used is equal to or more than the lower limit, a higher rust prevention effect can be obtained. When the amount of the top coat used is less than or equal to the above upper limit, excessive use of the top coat is suppressed.

Here, the “applicable part of the top coat” means the above-mentioned “location where the rust conversion agent is attached to the red rust steel material”, and usually the surface of the red rust layer or the top coat previously formed on the red rust layer. It means the surface of the coating film.
For example, when the surface of the application target portion of the top coating is rough, the area value of the surface of the application target portion of the top coating applied when the surface is viewed from above is used as the area value. That's fine.

  The presence or absence of rust conversion in the rust conversion process can be confirmed by observing the adhesion site of the rust conversion agent in the red rust steel material.

  For example, if the rust conversion agent adheres to a red rust layer on which no top coat film has been formed, the rust conversion agent adheres to the surface (attached surface) from red (red rust color) to black (black rust If the color is changed to (color), it can be determined that the rust conversion has progressed sufficiently. On the other hand, if it is not discolored in this way, it can be judged that rust conversion has not progressed or the progress of rust conversion is insufficient. Furthermore, if the rust conversion has progressed sufficiently, the occurrence of new red rust will be suppressed even after a long time has passed in the area where the rust conversion agent is attached, so that the color of black rust remains reflected. is there. On the other hand, if the rust conversion has not progressed or if the rust conversion has not progressed sufficiently, the red rust color will change if the rust conversion agent adheres to the area where the rust conversion agent has been attached. Even if there is an area that reflects or reflects the color of black rust, the color changes to reflect the color of red rust.

On the other hand, when the rust conversion agent adheres to the top coat film formed on the red rust layer, if the top coat film is lifted, rust conversion has not progressed or rust conversion has occurred. It can be judged that progress is inadequate. This is because structural changes such as floating occur in the red rust layer itself as new red rust is generated. On the other hand, if the lift of the top coat film is not recognized in this way, it can be determined that the rust conversion has sufficiently progressed. Furthermore, if the rust conversion has progressed sufficiently, the occurrence of new red rust will be suppressed even in a longer period of time in the area where the rust conversion agent is attached and in the vicinity thereof, so that the top coating film will float. It remains in an unacceptable state. On the other hand, if the rust conversion has not progressed or if the rust conversion has not progressed sufficiently, in the top coat film where the rust conversion agent is attached, it will be caused by the occurrence of new red rust after a longer period of time. And the float becomes large. Furthermore, depending on the case, a red rust layer may be exposed by partial collapse of a top coat film.
If the rust conversion agent adheres to the top coat film formed on the red rust layer, observing the top coat film in this way can confirm the presence or absence of rust conversion, but peel off the top coat film. The presence or absence of rust conversion can also be confirmed by directly observing the layer below the top coat as described above.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.

[Example 1]
The ship was operated at sea for 120 days. During this period, a plurality of iron plates with a size of 50 mm × 100 mm × 7 mm were placed on the deck and exposed to the sea breeze for aging.
Subsequently, on this ship, an iron plate in which red rust is generated by the storage over time is used as a test piece (hereinafter sometimes referred to as “test piece (T1)”), and the test piece (T1) is red rusted. The rust conversion agent (L1) was directly applied to the entire surface without dropping red rust, and the rust conversion agent (L1) was permeated into the red rust layer (initial infiltration step). The coating amount of the rust conversion agent (L1) at this time was 200 g (that is, 200 g / m ² ) per 1 m ² area of the red-rusted surface of the test piece (T1). Furthermore, the rust conversion agent (L1) was again applied to the test piece (T1) by the same method (repeated penetration step). During this time, the interval from the first application to the second application (the time interval between the initial infiltration process and the repeated infiltration process) is within 30 minutes to 2 hours in each test piece (T1). I made it. In addition, application | coating of these two rust conversion agents (L1) was performed on fine weather or cloudy weather.

The components of the rust conversion agent (L1) used here are shown below.
Rust conversion agent (L1):
In the rust conversion agent (L1) used in this example, the content of tannic acid is 1% by mass, the content of the resin other than the polyhydric phenol compound is 3% by mass, and the content of the organic solvent is 96% by weight,
The ratio of the content of toluene to the total content of the organic solvent is 35.42% by mass, the ratio of the content of cyclohexanone is 25% by mass, and the ratio of the content of methyl ethyl ketone is 13.33% by mass. Yes, the proportion of methyl isobutyl ketone content is 6.25% by mass, the proportion of acetone content is 6.25% by mass, and the proportion of ethylene glycol monobutyl ether content is 6.25% by mass. Yes, the proportions of the contents of 2-propanol, 1-butanol, 2-methyl-1-propanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, butyl acetate, 3-methoxybutyl acetate and kerosene are 0.9375 respectively. % By mass.
The resin other than the polyhydric phenol compound is an epoxy resin.

  Next, the test piece (T1) after the application of the rust converting agent (L1) twice was further aged by exposing the test piece (T1) to a sea breeze atmosphere for about 90 days on a ship. May be called). The test piece (T2) apparently had red rust traces disappeared and turned black. The imaging data of the test piece (T1) and the test piece (T2) are shown in FIG.

The surface part of the test piece (T2) was scraped off to obtain a black powder.
Separately, naturally occurring black rust (hereinafter sometimes referred to as “black rust spot product”) was collected from the hull of the ship without using the rust conversion agent (L1).
When a magnet that had been covered with tissue paper to eliminate the influence of static electricity was brought close to the black powder and black rust field product, the black powder and black rust field product were strongly attracted to the magnet.
From the above, it was confirmed that the black powder obtained from the test piece (T2) was black rust (magnetite) of a ferromagnetic material in consideration of its history.

On the other hand, the surface part of the test piece (T1) was scraped off to obtain a red powder.
About this red powder, when the magnet which covered tissue paper was brought close like the case of said black powder, this red powder was not attracted to the magnet. Thus, it was confirmed that it was a paramagnetic red rust (hematite) that covered the surface of the test piece (T1).

  From the above, it was confirmed that red rust was converted to black rust by the rust conversion agent (L1).

[Test Example 1]
A glass column having a packed portion having a length of 10 cm and an inner diameter of 1 cm was used, and cotton was packed in the lower opening of the packed portion.
Next, the filling portion was filled with ferric oxide (Fe ₂ O ₃ ) powder (3 g) to a height of 2 cm.
Next, the rust conversion agent (L1) (1.5 mL) was uniformly placed on the surface of the uppermost part of the ferric oxide layer in the filling part and allowed to stand for 5 minutes. And when the arrival place of the rust conversion agent (L1) in the ferric oxide layer in a filling part was confirmed visually visually, it was a place 4 mm below from the uppermost surface. That is, by standing for 5 minutes, the rust conversion agent (L1) penetrated from the uppermost surface of the ferric oxide layer to a depth of 4 mm.
As described above, the rust conversion agent (L1) has good permeability to the red rust layer, and can penetrate to the boundary region between the steel material mainly made of iron or iron and the red rust layer. Was confirmed.

  On the other hand, instead of the rust conversion agent (L1) (1.5 mL), a commercially available rust preventive paint “Acry 700 Primer J” (manufactured by China Paint Co., Ltd.) 3% by weight diluted solution (1.5 mL) was used. Except for the above, the permeability of this diluted solution was confirmed by the same method as described above. As a result, this diluted solution only reached a depth of 0.5 mm from the uppermost surface of the ferric oxide layer, and this changed even when left still for another 25 minutes (30 minutes in total). There wasn't. The concentration of the diluted solution is a concentration that is generally used for rust preventive paints, and this rust preventive paint has poor permeability to the red rust layer.

[Example 2]
In a ship operating at sea, for two pipes arranged in parallel on the deck, one uses a rust conversion agent (L1) and the other uses a commercially available rust preventive “Acry 700 Primer J” ( Rust prevention effect was confirmed using a Chinese paint company). More specifically, it is as follows.
About one piping, the rust conversion agent (L1) was apply | coated to the surface where red rust exists as it was, without drying the surface red rust, and it was made to dry. The coating amount of the rust conversion agent (L1) at this time was 200 g / m ² .
About the other piping, after carrying out the kelen process of the surface and removing a part of red rust, the commercially available rust preventive agent was apply | coated to this surface, and it was made to dry. The coating amount of the rust inhibitor at this time was 300 g / m ² .
For both pipes, a commercially available top coat “Acry 700 Top Coat ST” (manufactured by China Paint Co., Ltd.) was further applied on the application site of the rust conversion agent (L1) or the rust preventive and dried. At this time, the amount of the top coat applied was 200 g / m ² .

The construction was completed as described above, and thereafter, the operation of the ship was continued at sea, and the degree of occurrence of rust in both pipes over time was compared.
FIG. 2 shows imaging data of both pipes to which the rust conversion agent (L1) or the rust preventive agent is to be applied before application.
Moreover, the imaging data immediately after construction (before aging) of both piping which applied the rust conversion agent (L1) or the said rust preventive agent are shown in FIG.
Moreover, the imaging data in the stage (after time) of 139 days after construction of both piping which applied the rust conversion agent (L1) or the said rust preventive agent are shown in FIG.
Further, FIG. 5 shows imaging data of both pipes obtained at different angles at the same time when the imaging data shown in FIG. 4 is acquired.
In addition, FIG. 6 shows the imaging data of both pipes obtained at the same time and at a higher magnification at the time of acquisition of the imaging data shown in FIG.

As is apparent from FIGS. 2 to 6 (particularly FIGS. 4 to 6), in the pipes to which the rust conversion agent (L1) was applied, almost no rust was observed, whereas a commercially available rust inhibitor. In the pipe to which was applied, red rust occurred in a relatively wide area at the part surrounded by the two-dot chain line. In particular, as is apparent from FIGS. 5 to 6, in the piping to which a commercially available rust preventive agent was applied, the amount of red rust generated was large, the surface coating was lifted, and the corrosion was severe.
Thus, it was confirmed that an excellent rust prevention effect can be obtained by using the rust conversion agent (L1).

[Example 3]
In ships operating at sea, rust conversion agent (L1) is used in some areas of structures on the deck, and commercially available rust preventive "Acry 700 Primer J" in some other areas. The antirust effect was confirmed using (manufactured by China Paint Co., Ltd.). More specifically, it is as follows.
About one area | region, the rust conversion agent (L1) was apply | coated to the surface where red rust exists as it was, without drying the surface red rust, and it was made to dry. The coating amount of the rust conversion agent (L1) at this time was 180 g / m ² .
About the other area | region, after carrying out the kelen process of the surface and removing a part of red rust, the commercially available rust preventive agent was apply | coated to this surface, and it was made to dry. The coating amount of the rust inhibitor at this time was 290 g / m ² .
In both areas, a commercially available top coat “Acry 700 Top Coat ST” (manufactured by China Paint Co., Ltd.) was further applied on the application site of the rust conversion agent (L1) or the rust preventive and dried. At this time, the amount of the top coat applied was 200 g / m ² .

  The construction was completed as described above, and thereafter, the ship was operated at sea for 120 days, and the degree of occurrence of rust in both areas over time was compared. FIG. 7 shows the respective imaging data immediately after construction (before aging) and 90 days after construction (after aging) in the region to which the rust conversion agent (L1) is applied. FIG. 7A shows imaging data before aging, and FIG. 7B shows imaging data after aging. Moreover, each imaging data in the area | region which applied the said rust preventive agent immediately after construction (before aging) and the stage (after aging) 90 days after construction is shown in FIG. FIG. 8A shows imaging data before aging, and FIG. 8B shows imaging data after aging.

As is clear from FIG. 7, the generation of rust was suppressed in the region where the rust conversion agent (L1) was applied. On the other hand, as is apparent from FIG. 8, in the region where the commercially available rust preventive agent was applied, red rust was generated in a wide range mainly at the site surrounded by the two-dot chain line.
Thus, it was confirmed that an excellent rust prevention effect can be obtained by using the rust conversion agent (L1).

  INDUSTRIAL APPLICABILITY The present invention can be used for suppressing the progress of rust generation in steel materials.

The present invention is a rust conversion method for converting the red rust to black rust in a red rust steel material having a red rust layer on the surface of a steel material mainly composed of iron or iron, and has an action of converting red rust to black rust. A permeation step for infiltrating the liquid rust conversion agent into the red rust layer; and a rust conversion step for converting red rust in the red rust layer to black rust by the permeated rust conversion agent in a sea breeze atmosphere; A rust conversion method is provided.
In the rust conversion method of the present invention, it is preferable that in the infiltration step, the rust conversion agent is infiltrated into a boundary region between the steel material mainly made of iron or iron and the red rust layer .

In the rust conversion method of the present invention, the rust conversion agent may contain a polyhydric phenol compound as an active ingredient, the polyhydric phenol compound, a resin other than the polyhydric phenol compound, and an organic solvent. preferable.
In the rust conversion method of the present invention, the content of the polyphenol compound in the rust conversion agent is 0.5 to 5% by mass, the content of the resin is 1 to 10% by mass, and the organic It is preferable that content of a solvent is 85-98.5 mass% .

Claims (6)

In a red rust steel material having a red rust layer on the surface of a steel material mainly made of iron or iron, a rust conversion method for converting the red rust to black rust,
A permeation step in which a liquid rust conversion agent having an action of converting red rust into black rust penetrates into the red rust layer;
A rust conversion method comprising: a rust conversion step of converting red rust in the red rust layer into black rust by the permeated rust conversion agent in a sea breeze atmosphere.   2. The rust conversion method according to claim 1, wherein in the infiltration step, the rust conversion agent is infiltrated into a boundary region between the steel material made of iron or iron as a main component and the red rust layer.   The rust conversion method according to claim 1 or 2, wherein the red rust layer is not subjected to keren treatment or three kinds of kelen treatment is performed before the infiltration step.   The said rust conversion agent makes a polyhydric phenol compound an active ingredient, The said polyhydric phenol compound, resin other than the said polyhydric phenol compound, and an organic solvent are contained, The any one of Claims 1-3. The rust conversion method described in 1.   The content of the polyphenol compound in the rust conversion agent is 0.5 to 5% by mass, the content of the resin is 1 to 10% by mass, and the content of the organic solvent is 85 to 98. The rust conversion method according to claim 4, which is 5% by mass. A rust conversion agent having an action of converting red rust to black rust and comprising a polyphenol compound as an active ingredient,
The content of the polyhydric phenol compound in the rust conversion agent is 0.5 to 5% by mass, the content of the resin other than the polyhydric phenol compound is 1 to 10% by mass, and the content of the organic solvent The amount is 85-98.5% by weight,
The ratio of the content of toluene to the total content of the organic solvent is 27 to 37% by mass, the ratio of the content of cyclohexanone is 17 to 27% by mass, and the ratio of the content of methyl ethyl ketone is 5 to 15% by mass. %, The proportion of methyl isobutyl ketone content is 2-8% by mass, the proportion of acetone content is 2-8% by mass, and the proportion of ethylene glycol monobutyl ether content is 2-8% by mass. The ratio of the content of 2-propanol, 1-butanol, 2-methyl-1-propanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, butyl acetate, 3-methoxybutyl acetate and kerosene is 1 respectively. Rust conversion agent that is less than mass%.