JP7077121B2 - Repairable plating base material - Google Patents

Description

The present invention relates to a restorable plating substrate.

As an automobile part, a galvanized steel sheet having a zinc-plated layer formed on the surface of the steel sheet is generally used. Zinc contained in the galvanized layer shows a higher ionization tendency than iron contained in the steel sheet. Therefore, when the steel sheet is exposed due to scratches formed on the zinc-plated layer, the zinc-plated layer has sacrificial anticorrosion performance in which zinc is eluted and a protective film in which the eluted zinc forms a film on the surface of the exposed steel sheet. It has the ability to form, self-repairs, and exhibits corrosion resistance. However, the conventional galvanized steel sheet could not exhibit sufficient corrosion resistance.

Therefore, Patent Document 1 reports an anticorrosion coating provided on the surface of a metal substrate, which has a base portion made of conductive fine particles and a surface portion made of a conductive polymer. However, even with such a technique, it cannot be said that sufficient corrosion resistance is exhibited at present.

Further, Patent Document 2 discloses a repair agent containing zinc sulfate, sodium dihydrogen phosphate and aminotris (methylenephosphonic acid).

Japanese Unexamined Patent Publication No. 2010-174273 Japanese Unexamined Patent Publication No. 2018-28115

The inventors of the present invention have found a new problem that sufficient corrosion resistance cannot be obtained even if one polymer layer is formed on the surface of the plating layer and the polymer layer contains the repair agent of Patent Document 2. ..

An object of the present invention is to provide a repairable plating base material that exhibits more sufficient corrosion resistance.

The present invention
The surface of the metal substrate has a plating layer containing a metal A having a higher ionization tendency than the metal constituting the metal substrate, and two or more polymer layers formed on the plating layer. A repairable plating base material in which two or more polymer layers contain a phosphoric acid compound, a phosphonic acid compound, and a compound containing a metal B having a higher ionization tendency than the metal constituting the metal base material.
The compound containing the metal B having a high ionization tendency is contained in a polymer layer different from the polymer layer containing at least one of the phosphoric acid compound or the phosphonic acid compound among the two or more polymer layers. , Repairable plating base material,
Regarding.

The repairable plating substrate of the present invention further exhibits sufficient corrosion resistance. More specifically, the repairable plating base material of the present invention is more excellent in sacrificial anticorrosion performance and protective film forming ability even if scratches that reach the metal base material are formed in an actual use environment. Further, it has good self-repairing property and exhibits more sufficient corrosion resistance.
The repairable plating base material of the present invention is particularly useful when a high-tensile material (high-strength steel plate) is used as the metal base material.

A schematic cross-sectional view of an example of a plating base material that can be used for the repairable plating base material of the present invention is shown. The schematic cross-sectional view of the repairable plating base material which concerns on 1st Embodiment of this invention is shown. A schematic cross-sectional view of the repairable plating base material for explaining an example of an embodiment in which a defect (scratch) is formed in the repairable plating base material according to the first embodiment of the present invention and a protective film is formed is shown. The schematic cross-sectional view of the repairable plating base material which concerns on 2nd Embodiment of this invention is shown. A schematic cross-sectional view of the repairable plating base material for explaining an example of an embodiment in which a defect (scratch) is formed in the repairable plating base material according to the second embodiment of the present invention and a protective film is formed is shown. A schematic cross-sectional view of the test piece produced in Example 1 is shown. A schematic cross-sectional view of the test piece produced in Example 2 is shown. A schematic cross-sectional view of the test piece produced in Comparative Example 1 is shown. A schematic cross-sectional view of the test piece produced in Comparative Example 2 is shown. A schematic cross-sectional view of the test piece produced in Reference Example 1 is shown. A schematic cross-sectional view of the test piece produced in Example 3 is shown. The schematic block diagram of the apparatus for evaluating the restoration agent of this invention is shown. The graph which shows the relationship of the immersion time-polarization resistance of the test piece prepared in an Example is shown. The graph which shows the relationship of the immersion time-polarization resistance of the test piece prepared in an Example is shown. A schematic cross-sectional view for explaining the difference in the formation mechanism of the protective film when the test pieces prepared in Example 1 and Example 3 are used is shown. A scanning electron microscope (SEM) photograph of the exposed surface of the steel plate in the scratched portion after the immersion time of 48 hours in the test piece of Example 1 is shown. It is a mapping image of Fe element in FIG. 11A. It is a mapping image of the Zn element in FIG. 11A. It is a mapping image of P element in FIG. 11A. It is a mapping image of O element in FIG. 11A. It is a mapping image of N element in FIG. 11A. It is an enlarged photograph of the part surrounded by a white line in FIG. 11A. It is an enlarged photograph of the part surrounded by a white line in FIG. 11B. It is an enlarged photograph of the part surrounded by a white line in FIG. 11E. It is an enlarged photograph of the part surrounded by a white line in FIG. 11C. It is an enlarged photograph of the part surrounded by a white line in FIG. 11D. A scanning electron microscope (SEM) photograph of the exposed surface of the steel plate in the scratched portion after the immersion time of 3 hours in the test piece of Example 1 is shown. It is a mapping image of Fe element in FIG. 12A. It is a mapping image of the Zn element in FIG. 12A. It is a mapping image of O element in FIG. 12A. It is a mapping image of the P element in FIG. 12A. It is a mapping image of N element in FIG. 12A. A scanning electron microscope (SEM) photograph of the exposed surface of the steel plate in the scratched portion after the immersion time of 48 hours in the test piece of Reference Example 1 is shown. It is a mapping image of Fe element in FIG. 13A. It is a mapping image of the Zn element in FIG. 13A. It is a mapping image of O element in FIG. 13A. It is a mapping image of P element in FIG. 13A. It is a mapping image of N element in FIG. 13A. A scanning electron microscope (SEM) photograph of the exposed surface of the steel plate in the scratched portion after the immersion time of 48 hours in the test piece of Example 3 is shown. It is a mapping image of Fe element in FIG. 14A. It is a mapping image of the Zn element in FIG. 14A. It is a mapping image of O element in FIG. 14A. It is a mapping image of P element in FIG. 14A. The graph which shows the error range (error bar) of the polarization resistance after 48 hours in the test piece prepared in Example 1 etc. is shown.

[Repairable plating base material]
The repairable plating substrate of the present invention has a polymer layer formed on the plating layer of the plating substrate. Since the repairable plating substrate of the present invention contains a repair agent in the polymer layer, it protects the inner surface of the defect, particularly the surface of the exposed metal substrate, when a defect reaching the metal substrate from the surface of the polymer layer is formed. It forms a film and becomes repairable (particularly self-repairing). Hereinafter, the present invention will be described in detail with reference to the drawings, but various elements in the drawings are merely schematically and exemplified for the purpose of understanding the present invention, and the appearance, dimensional ratio, etc. are different from the actual ones. obtain. The "vertical direction", "left-right direction", and "front-back direction" used directly or indirectly in the present specification correspond to the directions corresponding to the vertical direction, the left-right direction, and the front-back direction in the figure, respectively. Unless otherwise specified, the same sign or symbol shall indicate the same member or the same meaning.

(Plating base material)
As shown in FIG. 1A, the plating base material 10 has a metal base material 1 and a plating layer 2 formed on the surface of the metal base material. The metal base material 1 may be any base material containing a metal, and usually contains iron, and may optionally contain carbon, silicon, manganese, phosphorus, sulfur, and the like. In the metal substrate, the carbon content is 1% by weight or less, particularly 0.8% by weight or less, and the content of silicon, manganese, phosphorus, sulfur, etc. is 0.5% by weight or less, particularly 0.3% by weight, respectively. % Or less, and the rest is iron.

As the metal base material 1, in the field of automobile parts, a steel plate is preferable, and a so-called carbon steel plate, particularly a high-strength steel plate (high-tensile material), is more preferable.

The plating layer 2 contains a metal having a higher ionization tendency than the metal constituting the metal base material 1 as a main component. The metal having a high ionization tendency contained as a main component of the plating layer may be hereinafter referred to as "metal A having a high ionization tendency". When the metal base material 1 is a steel plate, the metal constituting the metal base material 1 is iron. Metals with a higher ionization tendency than iron include, for example, one or more metals selected from the group consisting of zinc, aluminum, magnesium and zirconium. Zinc is preferred. The metal A having a high ionization tendency contained in such a plating layer 2 usually contributes to the formation of a protective film described in detail later in the form of ions.

The plating layer 2 is preferably a zinc plating layer from the viewpoint of forming a protective film on the exposed surface of the metal base material 1. The zinc plating layer is a plating layer containing zinc, and is preferably a zinc alloy layer.

As a method for forming the plating layer 2, any plating method may be adopted, for example, a wet plating method such as a so-called electroplating method, an electroless plating method and a hot-dip plating method; and a so-called vacuum plating method (physical vapor deposition). A dry plating method such as a method (PVD method)), a chemical vapor deposition method (CVD method), and an impact plating method can be mentioned. A dry plating method, particularly an impact plating method, is preferable. In the impact plating method, a plating layer (coating) is formed by projecting composite particles having metal particles constituting the plating layer on the outer shell portion of the central portion (for example, an iron core) onto an object to be treated (metal substrate 1). How to do it. FIG. 1A shows a schematic cross-sectional view of a plating substrate in which the plating layer 2 is formed by an impact plating method and an interface and gaps of constituent metal particles are present inside the plating layer 2, but the plating layer is another It may be formed by the method and have a form in which the interface and the gap of the constituent metal particles do not exist.

The thickness of the plating layer 2 is not particularly limited, and may be, for example, 1 μm or more, usually 1 to 50 μm, and particularly 1 to 10 μm.

(Repair agent)
The repair agent contains a phosphoric acid compound, a phosphonic acid compound, and a compound containing a metal having a higher ionization tendency than the metal constituting the metal substrate 1 (hereinafter, may be referred to as compound B). The repair agent is an agent that forms a protective film on the exposed surface of the metal substrate.

The phosphoric acid compound is one or more inorganic phosphoric acid compounds selected from the group consisting of phosphoric acid (H ₃ PO ₄ ) and phosphate. Phosphate is preferable from the viewpoint of forming a protective film. Phosphate is a phosphate ion such as a first phosphate ion (H ₂ PO _4- ⁾ , a second phosphate ion (HPO _4-2 ) or a _third phosphate ion (PO ^4-3- ), and a ^positivity . It is a salt with ions. From the viewpoint of forming the protective film, the preferred phosphate ion is a first phosphate ion, a second phosphate ion, and more preferably a first phosphate ion. Cations are one or more ions selected from the group consisting of monovalent metal ions, divalent metal ions, trivalent metal ions and ammonium ions. It is preferably a monovalent metal ion and an ammonium ion. Examples of the metal constituting the monovalent metal ion include alkali metals (for example, sodium, potassium and lithium), and sodium and potassium are preferable. Examples of the metal constituting the divalent metal ion include alkaline earth metals (for example, magnesium, calcium, strontium, barium) and manganese, preferably calcium, barium and manganese. Examples of the metal constituting the trivalent metal ion include chromium and aluminum, and chromium is preferable.

Specific examples of the phosphoric acid compound preferable from the viewpoint of forming a protective film include phosphoric acid (H ₃ PO ₄ ), sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, and calcium dihydrogen phosphate. , Barium dihydrogen phosphate, Manganese dihydrogen phosphate, Lithium dihydrogen phosphate, Sodium ammonium hydrogen phosphate, Diammonium hydrogen phosphate, Dipotassium hydrogen phosphate, Disodium hydrogen phosphate, Barium hydrogen phosphate, Phosphoric acid Examples include manganese hydrogen (II), chromium (III) phosphate, tripotassium phosphate, trisodium phosphate, and condensed phosphate compounds. The condensed phosphoric acid compound is, for example, a compound composed of anions and cations such as tripolyphosphoric acid, pyrophosphoric acid, metaphosphoric acid, and phosphite, and the cations are, for example, alkali metal ions, alkaline earth metal ions, and the like. It is selected from amphoteric metal ions (zinc ion, aluminum ion).

More preferable phosphoric acid compounds from the viewpoint of forming a protective film include sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, sodium ammonium hydrogen phosphate, diammonium hydrogen phosphate, and dipotassium hydrogen phosphate. , Disodium hydrogen phosphate, trisodium phosphate, condensed phosphoric acid compounds. Specific examples of preferred condensed phosphate compounds include, for example, aluminum dihydrogen tripolyphosphate, calcium tripolyphosphate, zinc tripolyphosphate, sodium tripolyphosphate, calcium metaphosphate, calcium metaphosphate, calcium pyrophosphate, calcium pyrophosphate, aluminum phosphite, zinc phosphite. And so on.

Phosphoric acid compounds are readily available as commercial products. Two or more kinds of compounds may be used as a phosphoric acid compound.

The phosphonic acid compound is not particularly limited as long as it contains an atom having an unshared electron pair that contributes to the adsorption of the protective film on the metal substrate 1, and is, for example, a group consisting of a nitrogen-containing phosphonic acid compound and a salt thereof. One or more organic phosphonic acid compounds selected from. The organic phosphonic acid compound means a compound having an organic group and a phosphono group. Examples of the organic group include an alkylene group, and an alkylene group having 1 to 3 carbon atoms is particularly preferable. The phosphono group is represented by −P (= O) (OH) ₂ and may have a salt form. The fact that the phosphono group has a salt form means that the hydrogen ion at the hydroxyl group of the phosphono group may be liberated and replaced with a metal ion or the like. Examples of the metal ion include sodium ion, potassium ion, and calcium ion.

The nitrogen-containing phosphonic acid compound is not particularly limited as long as it is an organic compound containing a nitrogen atom and a phosphono group, and is, for example, aminotris (methylenephosphonic acid) (ATMP) (structural formula: N [CH ₂ PO (OH)). ₂ ] ₃ ), aminotris (ethylenephosphonic acid) (structural formula: N [CH ₂ CH ₂ PO (OH) ₂ ] ₃ ), and phosphono group-containing amines such as metal salts thereof. When the compound has two or more hydroxyl groups in one molecule, the metal salt may be one in which hydrogen ions in some hydroxyl groups are replaced with metal ions, or hydrogen ions in all the hydroxyl groups are present. It may be substituted with a metal ion.

Phosphonic compounds are readily available as commercial products. Two or more kinds of compounds may be used as a phosphonic acid compound.

The phosphoric acid compound and the phosphoric acid compound are usually contained in a weight ratio of 10/90 to 90/10 (phosphoric acid compound / phosphoric acid compound), and are preferably 20/80 to 80/20 from the viewpoint of forming a protective film. It is more preferably contained in a weight ratio of 40/60 to 80/20, more preferably 45/55 to 65/35. When two or more kinds of compounds are used as the phosphoric acid compound, the total amount thereof may be within the above range. When two or more kinds of compounds are used as the phosphonic acid compound, the total amount thereof may be within the above range.

Compound B is a compound containing a metal having a higher ionization tendency than the metal constituting the metal substrate 1. In the present specification, the metal having a high ionization tendency contained in such compound B contained in the repair agent is distinguished from the metal A having a high ionization tendency contained in the plating layer, and is referred to as "metal B having a high ionization tendency". There is that. Such a metal B having a high ionization tendency also contributes to the formation of a protective film in the form of ions. The metal B having a high ionization tendency may be selected from the metals within the same range as the metal A having a high ionization tendency described above, and is preferably a metal of the same type as the metal A having a high ionization tendency.

The metal B having a high ionization tendency is not particularly limited as long as the metal can exist in the form of ions in water, and examples thereof include zinc, iron, magnesium, cobalt, nickel, chromium, silver, zirconium, and aluminum. Among these metals, divalent to tetravalent (preferably divalent and tetravalent) metals, particularly zinc, iron, nickel, among these metals, from the viewpoint of forming a complex in water, particularly from the viewpoint of forming a complex with ATMP, Zirconium is preferred, zinc is more preferred. The compound containing the metal B having a high ionization tendency is not particularly limited as long as the metal can exist in the form of ions in water. Preferred specific examples of the compound containing the metal B having a high ionization tendency include zinc sulfate, iron sulfate, nickel sulfate, zinc sulfate, zinc nitrate, aluminum sulfate, aluminum nitrate, magnesium sulfate, magnesium nitrate and the like.

The compound B containing the metal B having a high ionization tendency is preferably contained in an amount of 10 to 400 parts by weight based on 100 parts by weight of the total amount of the phosphoric acid compound and the phosphonic acid compound, from the viewpoint of promoting the formation of the protective film. Therefore, it is particularly preferably contained in an amount of 30 to 300 parts by weight, more preferably 80 to 300 parts by weight, still more preferably 80 to 200 parts by weight, and most preferably 110 to 150 parts by weight. As the compound B containing the metal B having a high ionization tendency, two or more kinds of compounds may be used, and in that case, the total amount thereof may be within the above range.

By containing the repair agent in combination with the phosphoric acid compound, the phosphonic acid compound and the compound B, it is possible to form a protective film having excellent non-conductivity and adhesion on the surface of the metal substrate exposed by the formation of defects. , Corrosion resistance is improved more sufficiently. Fragrant compounds such as nitrate compounds, carbonate compounds, hydrogen carbonate compounds, chromium acid compounds, silicic acid compounds, metal fluorides, metal oxides, etc. may be used instead of phosphoric acid compounds, or instead of phosphonic acid compounds. Alternatively, even if an aliphatic carboxylic acid or an organic amine is used, the protective film is not formed, or even if it is formed, at least one of the non-conductiveness and the adhesiveness of the protective film is reduced, so that sufficient corrosion resistance can be obtained. do not have. Further, if the repair agent does not contain the compound B, the protective film is not sufficiently formed, so that sufficient corrosion resistance cannot be obtained. In the present specification, the non-conductive means the insulating property having a volume resistivity of 10 ¹² Ω · cm or more.

In the present invention, a protective film is formed on the surface of a metal substrate on which metals A and B, which have a high ionization tendency, a phosphoric acid compound, and a phosphonic acid compound are exposed. That is, at the time of forming the protective film, the phosphate ion of the phosphoric acid compound reacts with the ion of the metal A having a high ionization tendency contained in the plating layer and the ion of the metal B having a high ionization tendency contained in the compound B ( For example, a non-conductive compound is produced as a main skeleton component of a film by the following schematic reaction formula (I). On the other hand, the phosphonic acid compound forms a complex with the ions of the metals A and B having a high ionization tendency (for example, the following schematic reaction formula (II)), and the nitrogen atom contained in the phosphonic acid compound portion is an unshared electron thereof. By pairing, it exerts an adsorption action with the surface of the metal base material. Moreover, the presence of the phosphonic acid compound complex promotes the amorphization of the film and improves the flexibility and adhesion of the film to the surface of the metal substrate. As a result, it is considered that a protective film having excellent non-conductivity and adhesiveness is formed, and the corrosion resistance is further improved. The following schematic reaction equation is an example of a schematic representation of the formation of a product derived from a major substance involved in the formation of a protective film.

In the present specification, the corrosion resistance is a property that resists corrosion, and is a property that can sufficiently resist corrosion even if a defect is formed and a metal substrate is exposed. Corrosion resistance shall be used in a concept that includes self-repairing properties. Self-healing property is a property that even if the metal substrate is exposed due to the formation of defects, the protective film is formed on the surface of the exposed metal substrate to repair the defects. be.

The repair agent does not necessarily contain nanofibers, but is preferably contained. Nanofibers are fibers with diameters on the order of nano-order. By including such nanofibers in the repair agent, the repairable plating base material becomes more and more sufficiently corrosion resistant. The details of the mechanism by which the repairable plating substrate exhibits sufficient corrosion resistance due to the inclusion of nanofibers in the repair agent are not clear, but it is considered to be based on the following principles. When the nanofiber is contained, components such as a phosphoric acid compound, a phosphonic acid compound, and compound B (hereinafter, may be referred to as a phosphoric acid compound) move along the surface of the nanofiber. Therefore, when defects (scratches) are formed, the movement of these components in the polymer layer, which will be described later, is promoted, and the exudation from the layer is promoted. As a result, it is considered that a protective film (repair film) is more effectively formed on the exposed surface of the metal base material in the scratched portion, and sufficient corrosion resistance is exhibited.

The constituent materials of the nanofibers are not particularly limited as long as the diameter has a nanoorder. Specific examples of nanofibers include natural polymer nanofibers such as cellulose nanofibers, chitosan nanofibers, and gelatin nanofibers; polyolefin nanofibers, polyamide nanofibers, polyvinylidene fluoride nanofibers, acrylic nanofibers, and epoxy nanofibers. Synthetic polymer nanofibers such as fibers, polyurethane nanofibers and polyimide nanofibers; and carbon nanofibers, carbon nanotubes and the like can be mentioned. From the viewpoint of further promoting the exudation of phosphoric acid compounds and the like, preferable nanofibers are natural polymer nanofibers, particularly cellulose nanofibers. Cellulose nanofibers are fibers obtained by finely loosening plant fibers obtained from plants to nanosize, and those known as so-called reinforcing fibers in the field of plastics can be used.

The average fiber diameter of the nanofibers is usually 1 nm or more and 1000 nm or less, and is preferably 1 to 500 nm, more preferably 10 to 400 nm, and further preferably 100 to 300 nm from the viewpoint of promoting exudation of phosphoric acid compounds and the like.

The average fiber length of the nanofibers is usually 10 to 1000 μm, preferably 50 to 800 μm, more preferably 100 to 500 μm, still more preferably 200 to 400 μm from the viewpoint of promoting exudation of phosphoric acid compounds and the like.

For the average fiber diameter and average fiber length of the nanofibers, the average value of any 200 values measured from micrographs (SEM) is used.

When the repair agent contains nanofibers, the nanofibers are preferably contained in an amount of 1 to 200 parts by weight based on 100 parts by weight of the total amount of the phosphoric acid compound and the phosphoric acid compound, and promote leaching of the phosphoric acid compound and the like. From the above viewpoint, it is particularly preferably contained in an amount of 5 to 100 parts by weight, more preferably 10 to 80 parts by weight, still more preferably 10 to 60 parts by weight, and most preferably 20 to 40 parts by weight. Two or more kinds of compounds may be used for the nanofibers, in which case the total amount thereof may be within the above range.

(Polymer layer)
The polymer layer has a multi-layered structure of two or more layers and contains a repair agent. For example, when the polymer layer has a two-layer structure, as shown in FIG. 1B, the first polymer layer 41 and the second polymer layer 42 are sequentially formed (or laminated) on the plating layer 2, and as a result, the 2nd polymer layer is formed. The polymer layer having a layered structure includes a first polymer layer 41 laminated on the plating layer 2 and a second polymer layer 42 laminated on the first polymer layer 41. Further, for example, when the polymer layer has a three-layer structure, as shown in FIG. 1D, the first polymer layer 41, the second polymer layer 42, and the third polymer layer 43 are sequentially (or laminated) on the plating layer 2. As a result, the polymer layer having the three-layer structure is the first polymer layer 41 laminated on the plating layer 2, the second polymer layer 42 laminated on the first polymer layer 41, and the second polymer. The third polymer layer 43 laminated on the layer 42 is included. In the present specification, each polymer layer contains at least one component among the components of the phosphoric acid compound, the phosphonic acid compound, the nanofiber and the compound B constituting the repair agent. Therefore, each polymer layer can also be referred to as a repairable polymer layer from the viewpoint of contributing to the formation of the protective film.

The composition of two or more polymer layers constituting the polymer layer is different from each other. The difference in composition means that at least one selected from the group consisting of the types and amounts of the components of the repair agent contained in the polymer layer and the types of the polymers constituting the polymer layer is different. The two or more polymer layers usually contain different types of repair agent components from each other.

In the present invention, the compound B is contained in a polymer layer having two or more layers, which is different from the polymer layer containing at least one of the phosphoric acid compound and the phosphonic acid compound. Specifically, compound B is contained in a polymer layer containing neither a phosphoric acid compound nor a phosphonic acid compound. More specifically, compound B is contained in another polymer layer adjacent to the polymer layer containing at least one of the phosphoric acid compound and the phosphonic acid compound. Separation is the form of existence of a polymer layer that separates the interface between two polymer layers. In the present invention, by including the compound B in the polymer layer containing neither the phosphoric acid compound nor the phosphonic acid compound, the repairable plating base material becomes more sufficiently corrosion resistant. The details of the mechanism are not clear, but it is considered to be based on the following principles. When compound B is contained in one polymer layer together with a phosphoric acid compound and / or a phosphonic acid compound, the reaction (I) and / or (II) occurs in the polymer layer, and a product is produced. The exudation and release of the component out of the layer is hindered. Therefore, when compound B is contained in a polymer layer different from the polymer layer containing at least one of the phosphoric acid compound and / or the phosphoric acid compound, the reaction (I) and / or (II) in the layer occurs. In order to be suppressed, when the defect 13 reaching the metal substrate 1 as shown in FIGS. 1C and 1E is formed, each component is smoothly exuded and released out of the layer. As a result, it is considered that the protective film (repair film) 14 is more effectively formed on the exposed surface of the metal base material in the scratched portion, and further exhibits sufficient corrosion resistance. The movement of each component exuded from each polymer layer to the exposed surface of the metal substrate 1 may be achieved by the moisture adhering to the defect 13 (for example, rainwater) or by the moisture in the air. , Or by immersing the repairable plating substrate on which the defect 13 is formed in water. When compound B is contained in a polymer layer containing at least one of a phosphoric acid compound and / or a phosphonic acid compound, the reaction (I) and / or (II) occurs in the polymer layer, and a product is produced. , The exudation and release of each component to the outside of the layer is hindered, and the repairable plating substrate does not exhibit sufficient corrosion resistance.

In the repairable plating substrate of the present invention, the protective film 14 is selectively formed on the exposed surface of the metal substrate 1. This is not intended to be bound by any particular theory, but may be due to the following reasons:
(1) Since the metal base material 1 has a corrosion potential (negative) at the initial stage, when the metals A and B, which have a high ionization tendency, are electrostatically attracted to the exposed surface of the metal base material 1 as positive ions, in addition to the protective film. The constituent material of is also electrostatically attracted to the positive ion.
(2) The attracted ions are adsorbed on the surface of the metal substrate 1 and then bonded to each other to form a film. These form a two-dimensional or three-dimensional film, and at the same time, they are strongly adsorbed or bonded to the surface of the metal substrate 1 to form a film having high adhesion.

The fact that the protective film 14 is formed on the exposed surface of the metal substrate 1 can be easily confirmed by an SEM photograph of the surface or by an analysis of the film on the surface by XRD (X-ray diffraction method). be able to.

In the present specification, the defect 13 has a depth reaching the metal base material 1 from the surface of the polymer layer, and is also referred to as a scratch.

Specific examples of the polymer layer configuration in the present invention include the following configuration examples. In the following notation, when the polymer layer is a two-layer type, the component described on the left side is a component contained in the first embodiment 41, and the component described on the right side is a component contained in the second polymer layer 42. be. When the polymer layer is a three-layer type, the component described on the left side is the component contained in the first embodiment 41, the component described in the center is the component contained in the second polymer layer 42, and the component described on the right side. Is a component contained in the third polymer layer 43.

2-layer type: 1st polymer layer 41 / 2nd polymer layer 42
Constituent Example A1 = Compound B / Phosphoric acid compound + Phosphoric acid compound Constituent example A2 = Phosphoric acid compound + Phosphoric acid compound / Compound B

3-layer type: 1st polymer layer 41 / 2nd polymer layer 42 / 3rd polymer layer 43
Constituent Example B1 = Compound B / Phosphoric acid compound / Phosphoric acid compound Constituent example B2 = Compound B / Phosphoric acid compound / Phosphoric acid compound Constituent example B3 = Phosphoric acid compound / Compound B / Phosphoric acid compound Constituent example B4 = Phosphoric acid compound / Phosphoric acid compound / compound B
Configuration Example B5 = Phosphoric Acid Compound / Compound B / Phosphoric Acid Compound Configuration Example B6 = Phosphoric Acid Compound / Phosphoric Acid Compound / Compound B

In the present invention, for example, when the first polymer layer 41 and the second polymer layer 42 are sequentially formed on the plating layer 2, the compound B is the first polymer layer 41 and the compound B as in the constituent examples A1 and A2. It is contained in one of the polymer layers of the second polymer layer 42, and the phosphoric acid compound and the phosphonic acid compound are contained in the other polymer layer. At this time, from the viewpoint of further improving the corrosion resistance of the repairable plating substrate, the compound B is contained in the first polymer layer 41 and the phosphoric acid compound and the phosphoric acid compound are the second polymer as in the configuration example A1. It is preferably contained in the layer.

Further, for example, when three polymer layers (reference numerals 41 to 43) are formed on the plating layer 2, the compound B is one of the three polymer layers as in the constituent examples B1 to B6. It is contained in one polymer layer, and the phosphoric acid compound and the phosphonic acid compound are contained in different polymer layers from the two polymer layers other than the polymer layer containing compound B, respectively. When the first polymer layer 41, the second polymer layer 42, and the third polymer layer 43 are sequentially formed on the plating layer 2, the constituent examples B1 and B2 are formed from the viewpoint of further improving the corrosion resistance of the repairable plating base material. As described above, the compound B is contained in the first polymer layer 41, the phosphoric acid compound is contained in one of the second polymer layer 42 and the third polymer layer 43, and the phosphonic acid compound is contained. Is preferably contained in the other polymer layer. From the viewpoint of further improving the corrosion resistance of the repairable plating substrate, compound B is more preferably contained in the first polymer layer 41 and the phosphoric acid compound is contained in the third polymer layer 43 as in the configuration example B1. It is contained and the phosphonic acid compound is contained in the second polymer layer 42.

In each of the above configuration examples, all the polymer layers do not contain nanofibers, but from the viewpoint of smoother exudation of each component, the nanofibers are included in the polymer layer containing other components of the repair agent. It is preferably contained. The other component is a component of at least one of a phosphoric acid compound, a phosphonic acid compound, and compound B. Specifically, the nanofibers are contained in a polymer layer containing one or more components selected from the group consisting of phosphoric acid compounds, phosphonic acid compounds and compound B, from the viewpoint of further promoting the exudation of each component. Is preferable, and more preferably, it is contained in all polymer layers containing one or more components selected from the group.

The polymer constituting each polymer layer (for example, the first polymer layer 41, the second polymer layer 42, and the third polymer layer 43) is not particularly limited as long as it can embed the repair agent component, and is, for example, a cured polymer or a thermoplastic polymer. May be. The cured polymer is usually composed of a substrate resin and a cross-linking agent (or curing agent). The substrate resin is usually a resin having a crosslinkable functional group such as a hydroxyl group, an epoxy group, a carboxyl group, a silanol group, and an alkoxysilyl group. Specific examples of the substrate resin include epoxy resin, acrylic resin, polyester resin, alkyd resin, fluororesin, urethane resin, silicon-containing resin and the like. The cross-linking agent is selected according to the substrate resin. Specific examples of the cross-linking agent include, for example, melamine resin, amino (urea) resin, polyisocyanate compound, blocked polyisocyanate compound, epoxy compound, carboxyl group-containing compound, acid anhydride group-containing compound, alkoxysilyl group-containing compound, and polyamide amine. And so on. The polymers constituting the first polymer layer 41, the second polymer layer 42 and the third polymer layer 43 may be independently selected from the above polymers, but the protective film may be selected according to the exudation rate of the components from each layer. From the viewpoint of further and sufficiently forming the polymer, the same kind of polymer is preferable.

Each polymer layer (for example, the first polymer layer 41, the second polymer layer 42, and the third polymer layer 43) is a coating liquid obtained by mixing, for example, a desired repair agent component with a polymer or a precursor thereof. Can be manufactured by coating. If the polymer or its precursor is curable, it may usually be cured by heating or light irradiation. For example, in the case of curing by heating, the heating temperature and the heating time may be appropriately set according to the type of polymer. For example, when an epoxy resin and a polyamide amine are used, the heating temperature is preferably 50 to 120 ° C., particularly preferably 60 to 100 ° C., and the heating time is preferably 1 to 10 hours, particularly 5 to 10 hours.

In a polymer layer containing a phosphoric acid compound (eg, a first polymer layer, a second polymer layer or a third polymer layer), the content of the phosphoric acid compound is usually relative to the total amount of the polymer layer containing the phosphoric acid compound. , 0.1 to 20% by weight, preferably 0.5 to 10% by weight, and more preferably 0.5 to 5% by weight. When the phosphoric acid compound is contained in two or more polymer layers, the content of the phosphoric acid compound in each polymer layer may be within the above range.

In a polymer layer containing a phosphonic acid compound (eg, a first polymer layer, a second polymer layer or a third polymer layer), the content of the phosphonic acid compound is usually relative to the total amount of the polymer layer containing the phosphonic acid compound. , 0.1 to 20% by weight, preferably 0.5 to 10% by weight, and more preferably 0.5 to 5% by weight. When the phosphonic acid compound is contained in two or more polymer layers, the content of the phosphonic acid compound in each polymer layer may be within the above range.

In the polymer layer containing compound B (for example, the first polymer layer, the second polymer layer or the third polymer layer), the content of compound B is usually 1 to 1 to the total amount of the polymer layer containing the compound B. It is 20% by weight, preferably 1 to 10% by weight, and more preferably 2 to 8% by weight. When compound B is contained in two or more polymer layers, the content of compound B in each polymer layer may be within the above range.

In a polymer layer containing nanofibers (eg, a first polymer layer, a second polymer layer or a third polymer layer), the content of the nanofibers is usually 0. It is 1 to 20% by weight, preferably 0.5 to 10% by weight, and more preferably 0.5 to 5% by weight. When the nanofibers are contained in two or more polymer layers, the content of the nanofibers in each polymer layer may be within the above range.

In each polymer layer (eg, first polymer layer, second polymer layer or third polymer layer), the total content of the restorative component is typically 0.5-40% by weight based on the total amount of each polymer layer. Yes, preferably 2 to 30% by weight, more preferably 5 to 20% by weight. The total content of the repair agent component is, for example, the total content of the phosphoric acid compound, the phosphonic acid compound and the nanofibers when one polymer layer contains the phosphoric acid compound, the phosphonic acid compound and the nanofibers. The total content of the repair agent component is also, for example, the total content of the compound B and the nanofibers when one polymer layer is contained.

The thickness of each polymer layer (for example, a first polymer layer, a second polymer layer, or a third polymer layer) is preferably thicker from the viewpoint of exudation of each component, but the balance between exudation and cost of each component and automobile applications are preferable. From this point of view, it is usually 1 to 100 μm, preferably 1 to 50 μm, and more preferably 5 to 40 μm independently of each other.

An insulating layer may be formed between the plating layer 2 and the polymer layer. The insulating layer means a layer having an insulating property (particularly a polymer layer) having a volume resistivity of 10 ¹² Ω · cm or more. The formation of the insulating layer can prevent the moisture invading from the nanofibers from coming into direct contact with the metal. The insulating layer does not contain a component of a repairing agent, and can usually be produced by a material and method within the same range as the polymer layer (for example, the first polymer layer 41). The thickness of the insulating layer is usually 1 to 100 μm, preferably 1 to 50 μm, and more preferably 5 to 40 μm from the viewpoint of insulating properties.

In the restorable plating substrate of the present invention, any coat layer such as a so-called hard coat layer may be formed on the outermost surface of the polymer layer.

The restorable plating substrate of the present invention does not necessarily have to have a plating layer. The repairable plating base material of the present invention can also be referred to as a "repairable metal base material" when it does not have a plating layer. The "repairable metal substrate" of the present invention is the repairable plating group except that it does not have a plating layer and has the above-mentioned multilayer polymer layer directly formed on the surface of the metal substrate 1. Similar to wood.

(material)
The following materials were used.
-Epoxy resin (Hypon 20 Decro Gray; manufactured by Nippon Paint Co., Ltd., curing agent = polyamide amine, paint liquid: curing agent = 85: 15 (weight ratio))
-Carbon steel sheet (high ten material) (12 mm x 12 mm) (content ratio: carbon 0.5% by weight, silicon 0.02% by weight, manganese 0.2% by weight, phosphorus 0.1% by weight, sulfur 0.1% by weight) , The rest; iron)
-Zinc sulfate (hereinafter, may be abbreviated as "Zn")
-Cellulose nanofibers (Cerish; manufactured by Daicel, average fiber length 0.3 mm, average fiber diameter 0.2 μm) (hereinafter, may be abbreviated as “CNF”)
-Sodium dihydrogen phosphate (hereinafter, may be abbreviated as "PO ₄ ")
-ATMP sodium salt (hereinafter, may be abbreviated as "AT")

(Example 1)
A test piece having a schematic cross-sectional structure shown in FIG. 2 was manufactured. The details are as follows.

-Formation of the insulating layer 40 An epoxy resin was coated on a carbon steel sheet by a bar coating method so that the coating thickness (after drying) was 20 μm, and the insulating layer 40 was formed by holding and curing at 80 ° C. for 3 hours.

-Formation of the first polymer layer 41 Zinc sulfate and cellulose nanofibers were mixed with a spatula, the mixture was added to the epoxy resin, and the mixture was stirred and defoamed with a stirrer to prepare a coating liquid. The contents of zinc sulfate and cellulose nanofibers were 4.6% by weight and 1.0% by weight, respectively, based on the total amount.
The coating liquid was coated on the insulating layer by a bar coating method so that the coating thickness (after drying) was 20 μm, and the coating liquid was held at 80 ° C. for 3 hours to be cured to form the first polymer layer 41.

-Formation of the second polymer layer 42 Sodium dihydrogen phosphate, ATMP sodium salt and cellulose nanofibers were mixed with a spatula, the mixture was added to the epoxy resin, and the mixture was stirred and defoamed with a stirrer to prepare a coating liquid. .. The contents of sodium dihydrogen phosphate, ATMP sodium salt and cellulose nanofibers were 1.9% by weight, 1.5% by weight and 1.0% by weight, respectively, based on the total amount.
The coating liquid was coated on the first polymer layer by a bar coating method so that the coating thickness (after drying) was 20 μm, and the mixture was held at 80 ° C. for 3 hours to be cured to form the second polymer layer 42.

-Formation of the top coat layer 60 The top coat layer 60 was formed on the second polymer layer 42 by the same method as the method for forming the insulating layer 40. The topcoat layer 60 is a layer for preventing elution of the repairing agent from other than scratches formed later.

-Formation of scratches Scratches (scratches) with a length of 4 mm and a depth of 30 μm (depth of carbon steel plate only) were applied to the prepared test piece using a scratch tester with a load of 500 g.

(Example 2)
A test piece having a schematic cross-sectional structure shown in FIG. 3 was manufactured. The details are as follows.
Specimens were produced by the same method as in Example 1 except that cellulose nanofibers were not used to form the first polymer layer 41 and the second polymer layer 42.

(Comparative Example 1)
A test piece having a schematic cross-sectional structure shown in FIG. 4 was manufactured. The details are as follows.
A test piece was produced by the same method as in Example 1 except that the second polymer layer 42 was not formed and the following coating liquid was used for forming the first polymer layer 41.
-Coating liquid of the first polymer layer 41 Zinc sulfate, sodium dihydrogen phosphate, ATMP sodium salt and cellulose nanofibers are mixed with a spatula, the mixture is added to the epoxy resin, and the mixture is stirred and defoamed with a stirrer to coat. The liquid was prepared. The contents of zinc sulfate, sodium dihydrogen phosphate, ATMP sodium salts and cellulose nanofibers were 4.6% by weight, 1.9% by weight, 1.5% by weight and 1.0% by weight, respectively, based on the total amount. there were.

(Comparative Example 2)
A test piece having a schematic cross-sectional structure shown in FIG. 5 was manufactured. The details are as follows.
A test piece was produced by the same method as in Comparative Example 1 except that the cellulose nanofiber was not used for forming the first polymer layer 41.

(Reference example 1)
A test piece having a schematic cross-sectional structure shown in FIG. 6 was manufactured. The details are as follows.
A test piece was produced by the same method as in Comparative Example 1 except that zinc sulfate, sodium dihydrogen phosphate, ATMP sodium salt and cellulose nanofibers were not used for forming the first polymer layer 41.

(Example 3)
A test piece having a schematic cross-sectional structure shown in FIG. 7 was manufactured. The details are as follows.
The same as in Example 1 except that the coating liquid of the second polymer layer 42 was used for forming the first polymer layer 41 and the coating liquid of the first polymer layer 41 was used for forming the second polymer layer 42. A test piece was produced by the method.

(Example 4)
A test piece having a cross-sectional structure similar to that of the schematic cross-sectional structure shown in FIG. 1D was manufactured except that an insulating layer was formed in place of the plating layer 2 and scratches were provided. The details are as follows.

-Formation of the insulating layer The insulating layer was formed on the carbon steel sheet by the same method as the method for forming the insulating layer in Example 1.

-Formation of the first polymer layer 41 Zinc sulfate and cellulose nanofibers were mixed with a spatula, the mixture was added to the epoxy resin, and the mixture was stirred and defoamed with a stirrer to prepare a coating liquid. The contents of zinc sulfate and cellulose nanofibers were 4.6% by weight and 1.0% by weight, respectively, based on the total amount.
The coating liquid was coated on the insulating layer by a bar coating method so that the coating thickness (after drying) was 20 μm, and the coating liquid was held at 80 ° C. for 3 hours to be cured to form the first polymer layer 41.

-Formation of the second polymer layer 42 ATMP sodium salt and cellulose nanofibers were mixed with a spatula, the mixture was added to the epoxy resin, and the mixture was stirred and defoamed with a stirrer to prepare a coating liquid. The contents of the ATMP sodium salt and the cellulose nanofibers were 1.5% by weight and 1.0% by weight, respectively, based on the total amount.
The coating liquid was coated on the first polymer layer by a bar coating method so that the coating thickness (after drying) was 20 μm, and the mixture was held at 80 ° C. for 3 hours to be cured to form the second polymer layer 42.

-Formation of the third polymer layer 43 Sodium dihydrogen phosphate and cellulose nanofibers were mixed with a spatula, the mixture was added to the epoxy resin, and the mixture was stirred and defoamed with a stirrer to prepare a coating liquid. The contents of sodium dihydrogen phosphate and cellulose nanofibers were 1.9% by weight and 1.0% by weight, respectively, based on the total amount.
The coating liquid was coated on the second polymer layer by a bar coating method so that the coating thickness (after drying) was 20 μm, and the mixture was held at 80 ° C. for 3 hours to be cured to form the third polymer layer 43.

-Formation of the top coat layer The top coat layer was formed on the third polymer layer 43 by the same method as the method for forming the top coat layer of Example 1.

-Formation of scratches Scratches (scratches) with a length of 4 mm and a depth of 30 μm (depth of carbon steel plate only) were applied to the prepared test piece using a scratch tester with a load of 500 g.

(Evaluation 1)
In the electrochemical measuring apparatus 50 shown in FIG. 8, the test piece is immersed in the corrosive liquid 52 as the working electrode 51, the AC impedance is measured for 48 hours, the change in polarization resistance with time is measured, and the self-healing property of the test piece is improved. evaluated. As the corrosive liquid 52, 0.5% by weight saline solution was used at a constant temperature of 35 ° C. and air-saturated. A platinum electrode was used as the counter electrode 53, and an Ag / AgCl electrode was used as the reference electrode 54. 55 is a potentiostat and 56 is a frequency response analyzer (FRA).

The changes over time in the polarization resistance of each test piece are shown in FIGS. 9A to 9B. In these figures, the vertical axis shows the polarization resistance and the horizontal axis shows the immersion time. The higher the polarization resistance, the less likely it is that a corrosion reaction will occur at the wound. The graph showing the change over time of the test piece of Example 4 is omitted. For Example 4, in Evaluation 2 described later, the average value of the polarization resistance and its error range (maximum value and minimum value) are shown in FIG.

When only the epoxy resin was coated in Reference Example 1 (Plan), a high polarization resistance was shown at the initial stage of immersion, but the resistance value gradually decreased thereafter. It is considered that corrosion is progressing on the exposed surface of the steel sheet at the scratched part.

Based on the comparison between Examples 1, 3 and 4 and Comparative Example 1, and the comparison between Example 2 and Comparative Example 2, the number of polymer layers is two or more, a layer containing Zn and one layer containing PO ₄ and AT. It was clarified that the polarization resistance was increased and the corrosion was more sufficiently suppressed by separating the layers into the above layers. This is because when components such as Zn, PO ₄ and AT are contained in the polymer layer of one layer (Comparative Examples 1 and 2), the reactions of the reaction formulas (I) and (II) are carried out in the polymer layer of one layer. It is probable that the polarization resistance did not increase sufficiently because the exudation and release of each component to the wound were prevented. On the other hand, when Zn, PO ₄ and AT are separately contained in a layer containing Zn and one or more layers containing PO ₄ and AT, each component is smoothly exuded from the layer and then the reaction formula is formed. It is considered that the reaction of (I) and (II) occurred and the protective film (repair film) was more effectively formed on the exposed surface of the steel sheet at the scratched portion, so that the corrosion was suppressed more sufficiently.

From the comparison between Example 1 and Example 3, the corrosion suppressing effect is further improved by having two or more polymer layers and locating the layer containing Zn below the one or more layers containing PO ₄ and AT. It became clear that it would be even higher. As shown in FIG. 10, the Zn-rich layer, which is more effective in suppressing corrosion, is more likely to be formed on the exposed surface of the metal substrate than the layer composed of the composite product of Zn + PO ₄ + AT, so that the corrosion suppressing effect is more effective. It is expected that it will be even higher.

In Example 1, when a scanning electron microscope (SEM) photograph of the exposed surface of the steel sheet in the scratched portion after the immersion time of 48 hours was taken (FIG. 11A), a product having a diameter of about 1 μm covered the exposed surface. Was confirmed. At the same time, an element mapping image was obtained by an energy dispersive X-ray analyzer (EDS). 11B to 11F are mapping images of Fe, Zn, P, O and N elements in FIG. 11A, respectively. FIG. 11G is an enlarged photograph of the portion surrounded by the white line in FIG. 11A. FIG. 11H is an enlarged photograph of the portion surrounded by the white line in FIG. 11B. FIG. 11I is an enlarged photograph of the portion surrounded by the white line in FIG. 11E. FIG. 11J is an enlarged photograph of the portion surrounded by the white line in FIG. 11C. FIG. 11K is an enlarged photograph of the portion surrounded by the white line in FIG. 11D.
The photographs (actual: color copy) of FIGS. 11A to 11K and the photographs (actual: color copy) of FIGS. 12A to 12F, FIGS. 13A to 13F and FIGS. 14A to 14E described later are used as reference material (reference photograph) 1. Submit with the property submission form.

From FIGS. 11G, 11H and 11I, Fe and O are detected in different regions. From this, it can be seen that the detected Fe is derived from the metal surface.
From FIGS. 11I, 11J and 11K, Zn, P and O are detected in the same region. From this, it can be seen that the detected Zn, P and O are derived from the reaction products of the reaction formulas (I) and (II).

In Example 1, a scanning electron microscope (SEM) photograph of the exposed surface of the steel sheet in the scratched portion after the immersion time of 3 hours was taken (FIG. 12A). At the same time, an element mapping image was obtained by an energy dispersive X-ray analyzer (EDS). 12B to 12F are mapping images of Fe, Zn, O, P and N elements in FIG. 12A, respectively.

In Reference Example 1, a scanning electron microscope (SEM) photograph of the exposed surface of the steel sheet in the scratched portion after the immersion time of 48 hours was taken (FIG. 13A). At the same time, an element mapping image was obtained by an energy dispersive X-ray analyzer (EDS). 13B to 13F are mapping images of Fe, Zn, O, P and N elements in FIG. 13A, respectively.

In Example 3, a scanning electron microscope (SEM) photograph of the exposed surface of the steel sheet in the scratched portion after the immersion time of 48 hours was taken (FIG. 14A). At the same time, an element mapping image was obtained by an energy dispersive X-ray analyzer (EDS). 14B to 14E are mapping images of Fe, Zn, O and P elements in FIG. 14A, respectively.

(Evaluation 2)
The reproducibility of Examples 1, 3 and 4, Comparative Example 1 and Reference Example 1 was verified. Three or more test pieces were prepared in each Example / Comparative Example / Reference Example, the AC impedance was measured for 48 hours by the same method as in Evaluation 1, and the polarization resistance at the time of immersion for 48 hours was measured. The average value of the polarization resistance and its error range (maximum value and minimum value) are shown in the graph of FIG. The error bar in FIG. 15 represents the error range. In FIG. 15, the vertical axis indicates the polarization resistance (Ω · cm ² ).

The repairable plating base material of the present invention is useful in the field of articles (for example, metal products such as automobiles, home appliances, and metal building materials) in which corrosion suppression is required.

1: Metal base material 2: Plating layer 10: Plating base material 13: Defects (scratches)
14: Protective film 40: Insulation layer 41: First polymer layer 42: Second polymer layer 43: Third polymer layer

Claims (12)

The surface of the metal substrate has a plating layer containing a metal A having a higher ionization tendency than the metal constituting the metal substrate, and three polymer layers formed on the plating layer. The polymer layer of the layer is a repairable plating base material containing a phosphoric acid compound, a phosphonic acid compound, and a compound containing a metal B having a higher ionization tendency than the metal constituting the metal base material.
The compound containing the metal B having a high ionization tendency is contained in one of the three polymer layers, which is different from the polymer layer containing at least one of the phosphoric acid compound and the phosphonic acid compound. And
The phosphoric acid compound and the phosphonic acid compound are each contained in two polymer layers other than the polymer layer containing the compound containing the metal B having a high ionization tendency, and are contained in different polymer layers . Plating substrate. A first polymer layer, a second polymer layer, and a third polymer layer are sequentially laminated on the plating layer.
The compound containing the metal B having a high ionization tendency is contained in the first polymer layer.
The phosphoric acid compound is contained in one of the second polymer layer and the third polymer layer.
The repairable plating substrate according to claim 1 , wherein the phosphonic acid compound is contained in the other polymer layer. The surface of the metal substrate has a plating layer containing a metal A having a higher ionization tendency than the metal constituting the metal substrate, and two or more polymer layers formed on the plating layer. A repairable plating base material in which two or more polymer layers contain a phosphoric acid compound, a phosphonic acid compound, and a compound containing a metal B having a higher ionization tendency than the metal constituting the metal base material.
The compound containing the metal B having a high ionization tendency is contained in a polymer layer different from the polymer layer containing at least one of the phosphoric acid compound and the phosphonic acid compound among the two or more polymer layers . ,
In the polymer layer containing the compound containing the metal B having a high ionization tendency, the compound containing the metal B having a high ionization tendency is contained in an amount of 1 to 20% by weight based on the total amount of the polymer layer.
In the polymer layer containing the phosphoric acid compound, the phosphoric acid compound is contained in an amount of 0.1 to 20% by weight based on the total amount of the polymer layer.
In the polymer layer containing the phosphonic acid compound, the phosphonic acid compound is contained in an amount of 0.1 to 20% by weight based on the total amount of the polymer layer, and is a repairable plating base material. The phosphoric acid compound and the phosphonic acid compound are contained in a weight ratio of 10/90 to 90/10, and are contained in a weight ratio of 10/90 to 90/10.
Any of claims 1 to 3 , wherein the compound containing the metal B having a high ionization tendency is contained in an amount of 10 to 400 parts by weight with respect to 100 parts by weight of the total amount of the phosphoric acid compound and the phosphonic acid compound. Repairable plating base material described in Crab . The plated substrate has defects that reach the metal substrate and
The repairable plating substrate according to any one of claims 1 to 4 , wherein a protective film is formed on the surface of the metal A and B having a high ionization tendency, the phosphoric acid compound and the phosphonic acid compound. .. The first polymer layer and the second polymer layer are sequentially laminated on the plating layer, and the first polymer layer and the second polymer layer are sequentially laminated.
The compound containing the metal B having a high ionization tendency is contained in one of the first polymer layer and the second polymer layer.
The phosphoric acid compound and the phosphonic acid compound are dependent on claim 3, claim 4 or 5, which is dependent on claim 3, or claim 4, which is dependent on claim 3, which is contained in the other polymer layer. The repairable plating substrate according to claim 5 . The compound containing the metal B having a high ionization tendency is contained in the first polymer layer.
The repairable plating substrate according to claim 6 , wherein the phosphoric acid compound and the phosphonic acid compound are contained in the second polymer layer. The phosphoric acid compound is an inorganic phosphoric acid compound and is
The repairable plating substrate according to any one of claims 1 to 7 , wherein the phosphonic acid compound is an organic phosphonic acid compound. The inorganic phosphoric acid compound is one or more compounds selected from the group consisting of phosphoric acid (H ₃ PO ₄ ) and phosphate.
The repairable plating substrate according to claim 8 , wherein the organic phosphonic acid compound is one or more compounds selected from the group consisting of a nitrogen-containing phosphonic acid compound and a salt thereof. The phosphate is a salt of a cation with a first phosphate ion (H ₂ PO _4- ⁾ , a second phosphate ion ( ^HPO _4-2 ) or a _third phosphate ion (PO ^4-3- ). can be,
The cation is one or more ions selected from the group consisting of monovalent metal ion, divalent metal ion, trivalent metal ion and ammonium ion.
The repairable plating substrate according to claim 9 , wherein the nitrogen-containing phosphonic acid compound is a phosphono group-containing amine. The metal base material is a steel plate,
The metals A and B having high ionization tendency are one or more metals independently selected from the group consisting of zinc, aluminum, magnesium and zirconium.
The repairable plating substrate according to any one of claims 1 to 10 , wherein the plating layer is formed by an impact plating method. The plating layer is a zinc plating layer.
The claim that the compound containing the metal B having a high ionization tendency is selected from the group consisting of zinc sulfate, iron sulfate, nickel sulfate, zirconium sulfate, zinc nitrate, aluminum sulfate, aluminum nitrate, magnesium sulfate, and magnesium nitrate. The repairable plating substrate according to any one of 1 to 11 .

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