JP2019189924A - Repair agent for plating base material and repairable plating base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a repairing agent showing more sufficient corrosion resistance. A repairing agent for a plating base material having a plating layer containing a metal A having a higher ionization tendency than a metal forming the metal base material on a surface of the metal base material, and comprising a phosphoric acid compound, A repair agent comprising a phosphonate compound and a nanofiber. [Selection diagram] None

Description

  The present invention relates to a restoration agent for a plating substrate having a plating layer on the surface of a metal substrate and a repairable plating substrate.

  As an automobile part, a galvanized steel sheet in which a galvanized layer is 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 plate. For this reason, when a scratch is formed in the galvanized layer and the steel sheet is exposed, the galvanized layer has a sacrificial anticorrosive performance in which zinc elutes and a protective film in which the eluted zinc forms a film on the surface of the exposed steel sheet Has the ability to form, self-repairs, and exhibits corrosion resistance. However, the conventional galvanized steel sheet cannot 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 in such a technique, it cannot be said that sufficient corrosion resistance is exhibited.

  Patent Document 2 discloses a restoration agent containing zinc sulfate, sodium dihydrogen phosphate and aminotris (methylene phosphonic acid).

JP 2010-174273 A JP-A-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 restoration agent of Patent Document 2 is contained in the polymer layer. .

  An object of this invention is to provide the restoration | repair agent which shows more sufficient corrosion resistance.

The present invention
A restoration agent for a plating substrate having a plating layer containing a metal A having a higher ionization tendency than the metal constituting the metal substrate on the surface of the metal substrate,
Restoratives, including phosphate compounds, phosphonate compounds and nanofibers,
About.

The restoration agent of the present invention exhibits a further sufficient corrosion resistance. Specifically, the restoration agent of the present invention is more excellent in sacrificial anticorrosive performance and protective film forming ability even if scratches (scratches) reaching the metal substrate are formed on the plating substrate in an actual use environment, It has even better self-repairing properties and exhibits more sufficient corrosion resistance.
The restoration agent of the present invention is particularly useful when a high-tensile material (high-tensile steel plate) is used as the metal substrate.

The schematic sectional drawing of the plating base material of the 1st embodiment to which the restoration | repair agent of this invention was applied is shown. The schematic sectional drawing of the plating base material for demonstrating an example in which a defect (scratch) is formed in the plating base material of the 1st embodiment to which the restoration | repair agent of this invention was applied, and a protective film is formed is shown. . The schematic sectional drawing of the plating base material of the 2nd embodiment to which the restoration | repair agent of this invention was applied is shown. The schematic sectional drawing of the plating base material for demonstrating an example in which a defect (scratch) is formed in the plating base material of the 2nd embodiment to which the restoration | repair agent of this invention was applied, and a protective film is formed is shown. . The schematic sectional drawing of the plating base material of the 3rd embodiment to which the restoration | repair agent of this invention was applied is shown. The schematic sectional drawing of the plating base material for demonstrating an example in which a defect (scratch) is formed in the plating base material of the 3rd embodiment to which the restoration | repair agent of this invention was applied, and a protective film is formed is shown. . The schematic sectional drawing of the plating base material of the 4th embodiment to which the restoration | repair agent of this invention was applied is shown. The schematic sectional drawing of the plating base material for demonstrating an example in which a defect (scratch) is formed in the plating base material of the 4th embodiment to which the restoration | repair agent of this invention was applied, and a protective film is formed is shown. . The schematic sectional drawing of the test piece produced in Example 1 is shown. The schematic sectional drawing of the test piece produced in the comparative example 1 is shown. The schematic sectional drawing of the test piece produced in Example 2 is shown. The schematic sectional drawing of the test piece produced in the comparative example 2 is shown. The schematic sectional drawing of the test piece produced by the reference example 1 is shown. The schematic sectional drawing of the test piece produced in Example 3 is shown. The schematic block diagram of the apparatus for evaluating the restoration | repair agent of this invention is shown. The graph showing the relationship of the immersion time-polarization resistance of the test piece produced in the Example is shown. The graph showing the relationship of the immersion time-polarization resistance of the test piece produced in the Example is shown. The schematic sectional drawing for demonstrating the difference in the formation mechanism of a protective film when using the test piece produced in Example 1 and Example 3 is shown. The scanning electron microscope (SEM) photograph of the steel plate exposure surface in the wound part at the time of 48-hour immersion time in the test piece of Example 1 is shown. It is the mapping image of Fe element in FIG. 11A. It is a mapping image of Zn element in FIG. 11A. It is a mapping image of the P element in FIG. 11A. It is a mapping image of the O element in FIG. 11A. It is a mapping image of N element in FIG. 11A. It is an enlarged photograph of the enclosure part by the white line in FIG. 11A. It is an enlarged photograph of the enclosure part by the white line in FIG. 11B. It is an enlarged photograph of the enclosure part by the white line in FIG. 11E. It is an enlarged photograph of the enclosure part by the white line in FIG. 11C. It is an enlarged photograph of the enclosure part by the white line in FIG. 11D. The scanning electron microscope (SEM) photograph of the steel plate exposure surface in the wound part at the time of immersion time 3 hour passage in the test piece of Example 1 is shown. It is the mapping image of Fe element in FIG. 12A. It is a mapping image of Zn element in FIG. 12A. It is a mapping image of O element in FIG. 12A. It is a mapping image of P element in FIG. 12A. It is a mapping image of N element in FIG. 12A. The scanning electron microscope (SEM) photograph of the steel plate exposure surface in the wound part at the time of 48-hour immersion time in the test piece of the reference example 1 is shown. It is the mapping image of Fe element in FIG. 13A. It is a mapping image of Zn element in FIG. 13A. It is the 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. The scanning electron microscope (SEM) photograph of the steel plate exposure surface in the wound part at the time of 48-hour immersion time in the test piece of Example 3 is shown. It is the mapping image of Fe element in FIG. 14A. It is the mapping image of Zn element in FIG. 14A. It is a mapping image of O element in FIG. 14A. It is the mapping image of P element in FIG. 14A. The graph showing the error range (error bar) of the polarization resistance 48 hours after in the test piece produced in Example 1 etc. is shown.

[Restoration agent]
The restoration agent of the present invention is for a plating substrate, and when a defect reaching the metal substrate from the plating layer surface of the plating substrate is formed, the inner surface of the defect, particularly the exposed metal substrate surface A protective film is formed on the surface. Hereinafter, the present invention will be described in detail with reference to the drawings, but various elements in the drawings are merely schematically and exemplarily for understanding the present invention, and the appearance and dimensional ratio are different from the actual ones. obtain. The “vertical direction”, “left / right direction”, and “front / back direction” used directly or indirectly in this specification correspond to directions corresponding to the vertical direction, left / right direction, and front / back direction in the drawing, respectively. Unless otherwise specified, the same symbols or symbols indicate the same members or the same meaning.

  As shown in FIG. 1A, the plating substrate 10 includes a metal substrate 1 and a plating layer 2 formed on the surface of the metal substrate. The metal substrate 1 may be any substrate containing a metal, and usually contains iron, and may contain carbon, silicon, manganese, phosphorus, sulfur and the like as desired. 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. %, And the balance is iron.

  The metal substrate 1 is preferably a steel plate in the field of automobile parts, more preferably a so-called carbon steel plate, particularly a high-tensile steel plate (high-tensile material).

  The plating layer 2 contains a metal whose ionization tendency is higher than that of the metal constituting the metal substrate 1 as a main component. The metal having a high ionization tendency that is contained as the main component of the plating layer may be hereinafter referred to as “metal A having a high ionization tendency”. When the metal substrate 1 is a steel plate, the metal constituting the metal substrate 1 is iron. Examples of the metal having a higher ionization tendency than iron include one or more metals selected from the group consisting of zinc, aluminum, magnesium, and zirconium. Zinc is preferable. The metal A having a high ionization tendency contained in the plating layer 2 is usually in the form of ions and contributes to the formation of a protective film described in detail later.

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

  As a method for forming the plating layer 2, any plating method may be employed. For example, a so-called electroplating method, electroless plating method, hot plating method such as a hot dipping method, and so-called vacuum plating method (physical vapor deposition). Method (PVD method)), chemical vapor deposition (CVD), and impact plating. A dry plating method, particularly an impact plating method is preferred. In the impact plating method, a plating layer (film) is formed by projecting composite particles having metal particles constituting the plating layer on the outer shell of the central portion (for example, iron core) onto the object to be processed (metal substrate 1). It is a method to do. In FIG. 1A, a schematic cross-sectional view of a plating substrate in which the plating layer 2 is formed by impact plating and the interfaces and gaps of the constituent metal particles exist inside the plating layer 2 is shown. It may be formed by a method and have a form in which there are no interfaces and gaps between the constituent metal particles. From the viewpoint of accommodating the restoration agent of the present invention in the plating layer, the plating layer is preferably formed by impact plating.

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

  The restorative agents of the present invention include phosphate compounds, phosphonate compounds and nanofibers. The restoration agent is an agent that forms a protective film on the exposed surface of the metal substrate.

The phosphate compound is one or more inorganic phosphate compounds selected from the group consisting of phosphoric acid (H ₃ PO ₄ ) and phosphate. From the viewpoint of forming a protective film, a phosphate is preferable. The 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 positive ion. It is a salt with ions. From the viewpoint of forming the protective film, preferred phosphate ions are a first phosphate ion and a second phosphate ion, and more preferably a first phosphate ion. The cation is one or more ions selected from the group consisting of monovalent metal ions, divalent metal ions, trivalent metal ions and ammonium ions. Preferred are monovalent metal ions and ammonium ions. Examples of the metal constituting the monovalent metal ion include alkali metals (for example, sodium, potassium and lithium), preferably sodium and potassium. Examples of the metal constituting the divalent metal ion include alkaline earth metals (eg, magnesium, calcium, strontium, barium) and manganese, preferably calcium, barium and manganese. As a metal which comprises a trivalent metal ion, chromium and aluminum are mentioned, for example, Preferably it is chromium.

Specific examples of preferred phosphoric acid compounds from the viewpoint of forming a protective film include, for example, phosphoric acid (H ₃ PO ₄ ), sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, 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 Mention may be made of 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 an anion and a cation such as tripolyphosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphorous acid, etc., and the cation includes, for example, an alkali metal ion, an alkaline earth metal ion, and It is selected from amphoteric metal ions (zinc ions, aluminum ions).

  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, and condensed phosphate compounds. Specific examples of preferable condensed phosphate compounds include, for example, aluminum trihydrogenphosphate, calcium tripolyphosphate, zinc tripolyphosphate, sodium tripolyphosphate, calcium metaphosphate, calcium metaphosphate, calcium pyrophosphate, calcium pyrophosphate, aluminum phosphite, zinc phosphite Etc.

  Phosphoric acid compounds are readily available as commercial products. Two or more compounds may be used as the 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 to the metal substrate 1, and 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 phosphono group having a salt form means that a hydrogen ion at the hydroxyl group of the phosphono group may be released and substituted 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. For example, aminotris (methylenephosphonic acid) (ATMP) (structural formula: N [CH ₂ PO (OH)) ₂ ] ₃ ), aminotris (ethylene phosphonic acid) (structural formula: N [CH ₂ CH ₂ PO (OH) ₂ ] ₃ ), and phosphono group-containing amines such as metal salts thereof. In the case where the compound has two or more hydroxyl groups in one molecule, the metal salt may be one in which hydrogen ions at some hydroxyl groups are replaced with metal ions, or hydrogen ions at all hydroxyl groups are present. It may be substituted with a metal ion.

  The phosphonic acid compound is easily available as a commercial product. Two or more compounds may be used as the phosphonic acid compound.

  The phosphoric acid compound and the phosphonic acid compound are usually contained in a weight ratio of 10/90 to 90/10 (phosphoric acid compound / phosphonic acid compound), and preferably 20/80 to 80/20 from the viewpoint of forming a protective film. More preferably, it is contained in a weight ratio of 40/60 to 80/20, more preferably 45/55 to 65/35. When using 2 or more types of compounds as a phosphoric acid compound, those total amounts should just be in the said range. When using 2 or more types of compounds as a phosphonic acid compound, those total amounts should just be in the said range.

When the restoration agent of the present invention contains a phosphoric acid compound and a phosphonic acid compound in combination, a protective film excellent in non-conductivity and adhesion can be formed on the surface of the metal substrate exposed by the formation of defects. . As a result, it is considered that the corrosion resistance is more sufficiently improved. Instead of phosphoric acid compounds, compounds such as nitric acid compounds, carbonic acid compounds, hydrogen carbonate compounds, chromic acid compounds, silicic acid compounds, metal fluorides, metal oxides, or aromatic compounds can be used instead of phosphonic acid compounds. Even when an aliphatic carboxylic acid or an organic amine is used, a protective film is not formed, or even if it is formed, at least one of the non-conductive property or the adhesive property of the protective film is lowered, so that sufficient corrosion resistance is obtained. Absent. In the present specification, the term “nonconductive” refers to an insulating property having a volume resistivity of 10 ¹² Ω · cm or more.

  At the time of forming the protective film, the phosphate ion of the phosphate compound is reacted with the ion of the metal A having a high ionization tendency contained in the plating layer (for example, the following general reaction formula (I)), thereby forming the main skeleton of the film. A non-conductive compound is produced as a component. On the other hand, the phosphonic acid compound forms a complex with the ion of metal A having a high ionization tendency (for example, the following general reaction formula (II)), and the nitrogen atom contained in the phosphonic acid compound portion is caused by the unshared electron pair. Exhibits an adsorption action with the surface of the metal substrate. 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 excellent in non-conductivity and adhesion is formed, and the corrosion resistance is more sufficiently improved. In addition, the following general reaction formula is an example which shows roughly formation of the product derived from the main substance concerning formation of a protective film.

  In this specification, the corrosion resistance is a characteristic that resists corrosion, and is a characteristic that can sufficiently resist corrosion even when a defect is formed and a metal substrate is exposed. Corrosion resistance shall be used in a concept that includes self-healing properties. Self-healing is a characteristic that even if a metal substrate is exposed due to the formation of a defect, a protective film is formed on the surface of the exposed metal substrate, thereby exhibiting a behavior that repairs the defect. is there.

  It is preferable that the restoration | repair agent of this invention further contains the compound containing the metal with a high ionization tendency from a viewpoint of formation of a protective film. Hereinafter, a metal having a high ionization tendency contained in such a compound contained in the restorative agent may be referred to as “metal B having a high ionization tendency” in distinction from a metal A having a high ionization tendency contained in the plating layer. . 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 metals in the same range as the metal A having a high ionization tendency, and is preferably the same type of metal 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. From the viewpoint of forming a complex in water, particularly from the viewpoint of forming a complex with ATMP, among these metals, divalent to tetravalent (preferably divalent and tetravalent) metals, particularly zinc, iron, nickel, Zirconium is preferred and zinc is more preferred. The compound containing 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. Preferable specific examples of the compound containing metal B having a high ionization tendency include, for example, zinc sulfate, iron sulfate, nickel sulfate, zirconium sulfate, zinc nitrate, aluminum sulfate, aluminum nitrate, magnesium sulfate, magnesium nitrate and the like.

  The compound containing metal B having a high ionization tendency (hereinafter sometimes referred to simply as compound B) 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. From the viewpoint of promoting the formation of a protective film, it is particularly preferably 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. The Two or more kinds of compounds may be used as the compound containing metal B having a high ionization tendency, and in this case, the total amount thereof may be within the above range.

  The repair agent of the present invention includes nanofibers. A nanofiber is a fiber having a nano-order diameter. By including such nanofibers in the repairing agent, the repairing agent of the present invention exhibits further sufficient corrosion resistance. Although the details of the mechanism by which the restorative of the present invention contains nanofibers will show more sufficient corrosion resistance is not clear, it is thought to be based on the following principles and principles. When the nanofiber is contained, components such as a phosphoric acid compound and a phosphonic acid compound, and a compound containing a metal B having a high ionization tendency (hereinafter, sometimes referred to as a phosphoric acid compound) are included on the surface of the nanofiber. To move along. For this reason, when a defect (scratch) is formed, movement of these components in a layer to be described later is promoted, and exudation from the layer is promoted. As a result, it is considered that a protective film (restoration film) is more effectively formed on the exposed surface of the metal substrate in the scratched part and exhibits sufficient corrosion resistance. If the repair agent does not include nanofibers, the repair agent does not exhibit sufficient corrosion resistance.

  As long as the diameter of the nanofiber has a nano-order, the constituent material is not particularly limited. Specific examples of nanofibers include, for example, natural polymer nanofibers such as cellulose nanofiber, chitosan nanofiber, and gelatin nanofiber; polyolefin nanofiber, polyamide nanofiber, polyvinylidene fluoride nanofiber, acrylic nanofiber, and epoxy nano Examples thereof include synthetic polymer nanofibers such as fibers, polyurethane nanofibers, and polyimide nanofibers; and carbon nanofibers and carbon nanotubes. From the viewpoint of further promoting the exudation of phosphate compounds and the like, preferred 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 nanofiber is usually 1 nm or more and 1000 nm or less, and preferably 1 to 500 nm, more preferably 10 to 400 nm, and still more preferably 100 to 300 nm, from the viewpoint of promoting exudation of a phosphate compound or the like.

  The average fiber length of the nanofiber is usually 10 to 1000 μm, and preferably 50 to 800 μm, more preferably 100 to 500 μm, and still more preferably 200 to 400 μm from the viewpoint of promoting exudation of a phosphate compound or the like.

  As the average fiber diameter and average fiber length of the nanofiber, an average value of arbitrary 200 values measured from a micrograph (SEM) is used.

  The nanofiber is preferably contained in an amount of 1 to 200 parts by weight with respect to 100 parts by weight of the total amount of the phosphoric acid compound and the phosphonic acid compound, and particularly preferably 5 to 5 from the viewpoint of promoting exudation of the phosphoric acid compound and the like. 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 nanofiber, and in that case, the total amount thereof may be within the above range.

[Repairable plating substrate]
The present invention provides a repairable plating substrate. The repairable plating base means that the plating base has repairability (particularly self-repairability).

  The restorable plating base of the present invention is a plating base provided with the above-described restorative agent. In the restorative agent provided in the restorable plating substrate, the content ratio of the phosphoric acid compound, the phosphonic acid compound, the nanofiber, and the compound B that is optionally contained is within the above range.

For example, as shown in FIG. 1A, in a plating substrate 10 having a metal substrate 1 and a plating layer 2 formed on the surface of the metal substrate, a repair agent may be included in the plating layer 2.
Further, for example, as shown in FIGS. 1C, 1E, and 1G, when one or more polymer layers (for example, reference numerals 41 to 43) are formed on the plating layer 2, a phosphate compound that constitutes a restoration agent The phosphonic acid compound and the nanofiber may be independently contained in a layer selected from the group consisting of the plating layer 2 and one or more polymer layers (for example, reference numerals 41 to 43). In this case, when the restorative agent further includes the compound B, the compound B is included in a layer selected from the group consisting of the plating layer 2 and one or more polymer layers (for example, reference numerals 41 to 43). Also good. A metal having a high ionization tendency of Compound B also contributes to the formation of a protective film.

  In the present invention, the nanofiber is preferably contained in a layer (particularly a polymer layer) containing other components. The other component is at least one component selected from the phosphoric acid compound, the phosphonic acid compound and the compound B. Specifically, the nanofibers are preferably included in, for example, a layer containing a phosphoric acid compound and / or a phosphonic acid compound (particularly a polymer layer) and / or a layer containing a compound B (particularly a polymer layer). This is because nanofibers promote the exudation of other components from the layer (particularly the polymer layer).

  In the restorative plating base material of the present invention, since each component of the restorative agent is contained in either the plating layer or the polymer layer as described above, FIG. 1B, FIG. 1D, FIG. 1F and FIG. When the defect 13 reaching the metal base 1 is formed, each component oozes and moves to the exposed surface of the metal base 1. Each component is a material constituting the protective film 14 (that is, a metal, a phosphoric acid compound, and a phosphonic acid compound having a high ionization tendency). As a result, the protective film 14 is formed. The metal having a high ionization tendency that oozes on the exposed surface of the metal substrate 1 may be the metal A having a high ionization tendency that constitutes the plating layer 2, or the metal A having a high ionization tendency and the restoration agent. It may be a mixture with a compound derived from a compound containing metal B having a high ionization tendency. After the movement of each component in each layer is promoted by the nanofiber, the movement of each component exuded from each layer to the exposed surface of the metal substrate 1 is achieved by moisture (for example, rainwater) adhering to the defect 13. Alternatively, it may be achieved by moisture in the air, or may be achieved by immersing the repairable plating substrate in which the defect 13 is formed in water.

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 substrate 1 initially has a corrosion potential (negative), when a metal having a high ionization tendency is electrostatically attracted to the exposed surface of the metal substrate 1 as positive ions, other constituent materials of the protective coating Is also electrostatically attracted to the positive ions.
(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, strongly adsorb or bond to the surface of the metal substrate 1 to form a highly adhesive film.

  The formation of the protective film 14 on the exposed surface of the metal substrate 1 can be easily confirmed by an SEM photograph of the surface or by 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 that reaches the metal substrate 1 from the surface of the repairable plating substrate, and is also referred to as a scratch.

  Hereinafter, the restorative plating base material of the present invention will be described in detail according to the case where each component of the restorative agent of the present invention is contained in the plating layer and the case where it is contained in the polymer layer. It may be included in the layer and other components may be included in the polymer layer.

<When each component of the restoration agent is contained in the plating layer>
When the restoration agent is included in the plating layer, for example, in the above-described impact plating method, the restoration agent is further attached to the outer portion of the constituent metal particles of the outer portion of the composite particle projected onto the object to be processed (metal substrate 1). Let me. As a result, the repairing agent can be present in the interface and the gap between the constituent metal particles in the plating layer 2. In such a case, the content of the restoration agent (total amount) is usually 0.15 to 18.20% by weight, preferably 0.50 to 7.70% by weight, based on the total amount of the plating layer.

<When each component of the restoration agent is contained in the polymer layer>
When one or more polymer layers (for example, reference numerals 41 to 43) are formed on the plating layer 2 (for example, FIG. 1C, FIG. 1E and FIG. 1G), the phosphoric acid compound and the phosphonic acid compound are independent of each other. And included in a layer selected from the group consisting of the one or more polymer layers (for example, reference numerals 41 to 43). At this time, it is preferable that the nanofiber is contained in the polymer layer containing at least one of the phosphoric acid compound or the phosphonic acid compound from the viewpoint of promoting the exudation of each component. From the viewpoint of further promoting the exudation of each component, the nanofiber is preferably included in all of the polymer layers including at least one of a phosphate compound or a phosphonate compound. The phosphoric acid compound and the phosphonic acid compound may be contained in the same polymer layer or in different polymer layers. In this case, when the restorative agent further includes the compound B, the compound B may be included in a layer selected from the group consisting of the one or more polymer layers (for example, reference numerals 41 to 43). The nanofiber is preferably also contained in the polymer layer containing Compound B.

  The polymer layer includes at least one component among components such as a phosphoric acid compound, a phosphonic acid compound, a nanofiber, and a compound B that can constitute a restoration agent. Therefore, the polymer layer can also be referred to as a restorative polymer layer from the viewpoint of contributing to the formation of a protective film.

  When two or more polymer layers are formed, the two or more polymer layers have different compositions from each other. The difference in composition means that at least one selected from the group consisting of the type and amount of the component of the restoration agent contained in the polymer layer and the type of polymer constituting the polymer layer is different. Two or more polymer layers are usually different from each other in the types of components of the included repair agent.

  Hereinafter, the embodiment will be described in detail when the polymer layer is a single layer type or a multilayer type of two or more layers.

(Single layer polymer layer)
When one polymer layer (first polymer layer) 41 is formed on the plating layer 2 (for example, FIG. 1C), the phosphoric acid compound, the phosphonic acid compound, and the nanofiber are included in the first polymer layer 41. Yes. Preferably, compound B is also contained in the one polymer layer. Thus, in this case, the nanofibers are included in a polymer layer comprising a phosphate compound, a phosphonate compound and optionally added compound B.

  The polymer constituting the polymer layer 41 is not particularly limited as long as the restoration agent component can be embedded, and may be, for example, a cured polymer or a thermoplastic polymer. The cured polymer is usually composed of a base resin and a crosslinking agent (or curing agent). The base resin is usually a resin having a crosslinkable functional group such as a hydroxyl group, an epoxy group, a carboxyl group, a silanol group, or an alkoxysilyl group. Specific examples of the base resin include, for example, epoxy resins, acrylic resins, polyester resins, alkyd resins, fluororesins, urethane resins, and silicon-containing resins. The cross-linking agent is selected according to the base resin. Specific examples of the crosslinking agent include, for example, melamine resin, amino (urea) resin, polyisocyanate compound, block polyisocyanate compound, epoxy compound, carboxyl group-containing compound, acid anhydride group-containing compound, alkoxysilyl group-containing compound, and polyamidoamine. Etc.

  The content of the phosphoric acid compound in the polymer layer 41 is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, more preferably 0.5 to 0.5% with respect to the total amount of the polymer layer. 5% by weight.

  The content of the phosphonic acid compound in the polymer layer 41 is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, more preferably 0.5 to 5% by weight.

  The content of the nanofiber in the polymer layer 41 is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, more preferably 0.5 to 5% with respect to the total amount of the polymer layer. % By weight.

  When the polymer layer 41 contains the compound B, the content of the compound B in the polymer layer 41 is usually 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the total amount of the polymer layer. More preferably, it is 2 to 8% by weight.

  In the polymer layer 41, the total content of the phosphoric acid compound, the phosphonic acid compound, and the compound B is usually 0.5 to 40% by weight, preferably 2 to 30% by weight, based on the total amount of the polymer layer. More preferably, it is 5 to 20% by weight.

  The polymer layer 41 is manufactured by previously mixing the phosphoric acid compound, the phosphonic acid compound, the nanofiber, and the compound B, and then coating the obtained mixture with the polymer or its precursor to coat the coating liquid. be able to. When the polymer or its precursor has curability, it may be usually 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 using an epoxy resin and a polyamidoamine, 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 preferably 5 to 10 hours.

(Multilayer polymer layer)
When two or more polymer layers are formed (or laminated) on the plating layer 2 (for example, FIG. 1E and FIG. 1G), the phosphoric acid compound, the phosphonic acid compound, and the nanofiber are each independently two layers. It may be contained in any of the above polymer layers. When the restorative agent includes Compound B, the Compound B may also be included in any layer. For example, when the polymer layer has a two-layer structure, as shown in FIG. 1E, the polymer layer having the two-layer structure includes the first polymer layer 41 and the first polymer layer laminated on the plating layer 2. 41 includes a second polymer layer 42 laminated to 41. Further, for example, when the polymer layer has a three-layer structure, as shown in FIG. 1G, the polymer layer having the three-layer structure includes a first polymer layer 41 and a first polymer layer 41 laminated on the plating layer 2. And a third polymer layer 43 laminated on the second polymer layer 42.

  The nanofiber is preferably contained in a polymer layer containing at least one of a phosphoric acid compound and a phosphonic acid compound from the viewpoint of promoting exudation of each component (phosphoric acid compound and phosphonic acid compound). From the viewpoint of further promoting the exudation of each component, the nanofiber is preferably included in all of the polymer layers including at least one of a phosphate compound or a phosphonate compound. When the restorative agent contains compound B, the nanofiber is preferably also contained in the polymer layer containing compound B from the viewpoint of promoting the exudation of each component (compound B).

  Specific examples of such a preferable polymer layer configuration 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 included in the first polymer layer 41, and the component described on the right side is a component included in the second polymer layer 42. is there. When the polymer layer is a three-layer type, the components described on the left side are components included in the first polymer layer 41, the components described in the center are components included in the second polymer layer 42, and the components described on the right side Is a component contained in the third polymer layer 43. In each of the following configuration examples, all the polymer layers include nanofibers, but it is sufficient that at least one polymer layer includes nanofibers. From the viewpoint of further promoting the exudation of each component, the nanofiber is preferably contained in all polymer layers. From the viewpoint of further promoting the exudation of each component, the configuration examples A1 and A2 and B1 to B6 are more preferable, and the configuration examples A1 and A2 are more preferable.

Two-layer type: first polymer layer 41 / second polymer layer 42
Configuration Example A1 = Compound B + Nanofiber / Phosphate Compound + Phosphonic Acid Compound + Nanofiber Configuration Example A2 = Phosphate Compound + Phosphonic Acid Compound + Nanofiber / Compound B + Nanofiber Configuration Example A3 = Phosphate Compound + Nanofiber / Compound B + phosphonic acid compound + nanofiber configuration example A4 = compound B + phosphonic acid compound + nanofiber / phosphate compound + nanofiber configuration example A5 = phosphonic acid compound + nanofiber / phosphate compound + compound B + nanofiber configuration example A6 = phosphorus Acid compound + Compound B + Nanofiber / Phosphonic acid compound + Nanofiber

Three-layer type: first polymer layer 41 / second polymer layer 42 / third polymer layer 43
Configuration Example B1 = Compound B + Nanofiber / Phosphonic Compound + Nanofiber / Phosphate Compound + Nanofiber Configuration Example B2 = Compound B + Nanofiber / Phosphate Compound + Nanofiber / Phosphonic Compound + Nanofiber Configuration Example B3 = Phosphonic Acid Compound + nanofiber / compound B + nanofiber / phosphate compound + nanofiber configuration example B4 = phosphonic acid compound + nanofiber / phosphate compound + nanofiber / compound B + nanofiber configuration example B5 = phosphate compound + nanofiber / compound B + nanofiber / phosphonic acid compound + nanofiber configuration example B6 = phosphate compound + nanofiber / phosphonic acid compound + nanofiber / compound B + nanofiber

  In the present invention, from the viewpoint of further promoting the exudation of each component, the compound B is a phosphoric acid compound or a phosphonic acid compound among the two or more polymer layers as in the structural examples A1 and A2 and B1 to B6. It is preferably contained in a polymer layer different from the polymer layer containing at least one (compound B separate layer type). Specifically, it is preferable that the compound B is contained in a polymer layer containing neither a phosphoric acid compound nor a phosphonic acid compound. More specifically, the compound B is preferably 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 presence of a polymer layer that separates the interface between two polymer layers. By including Compound B in a polymer layer containing neither a phosphoric acid compound nor a phosphonic acid compound, the reaction (I) and / or (II) in the layer is suppressed, and the exudation of each component is further enhanced. Can be promoted.

  In the compound B separate layer type, for example, when the first polymer layer 41 and the second polymer layer 42 are sequentially formed (or laminated) on the plating layer 2, as in the configuration examples A1 and A2, the compound B Is contained in one of the first polymer layer 41 and 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 restorable plating base material, the compound B is included in the first polymer layer 41 as in the configuration example A1, and the phosphate compound and the phosphonic acid compound are the second polymer. It is preferable that it is contained in the layer.

  In the compound B separate layer type, and when, for example, three polymer layers (reference numerals 41 to 43) are formed (or laminated) on the plating layer 2, as in structural examples B1 to B6, Among the three polymer layers, the polymer layer is included in any one polymer layer, and the phosphoric acid compound and the phosphonic acid compound are respectively two polymer layers other than the polymer layer containing the compound B, They are contained in different polymer layers. When the 1st polymer layer 41, the 2nd polymer layer 42, and the 3rd polymer layer 43 are formed in order on the plating layer 2, from a viewpoint of the further improvement of the corrosion resistance of a repairable plating base material, structural example B1 and B2 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 or the third polymer layer 43, and the phosphonic acid compound. Is preferably contained in the other polymer layer. From the viewpoint of further improving the corrosion resistance of the repairable plating base material, more preferably, as in the structural example B1, the compound B is contained in the first polymer layer 41, and the phosphoric acid compound is contained in the third polymer layer 43. The phosphonic acid compound is contained in the second polymer layer 42.

  In a polymer layer containing a phosphoric acid compound (for example, the first polymer layer, the second polymer layer or the third polymer layer), the content of the phosphoric acid compound is usually based on 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 may be within the above range in each polymer layer.

  In the polymer layer containing the phosphonic acid compound (for example, the first polymer layer, the second polymer layer, or the third polymer layer), the content of the phosphonic acid compound is usually based on 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 may be within the above range in each polymer layer.

  In a polymer layer including nanofibers (for example, the first polymer layer, the second polymer layer, or the third polymer layer), the content of nanofibers is generally 0. 0 relative to the total amount of polymer layers including the nanofibers. 1 to 20% by weight, preferably 0.5 to 10% by weight, more preferably 0.5 to 5% by weight. When nanofibers are contained in two or more polymer layers, the content of nanofibers in each polymer layer may be in the above range.

  In the polymer layer containing the compound B (for example, the first polymer layer, the second polymer layer, or the third polymer layer), the content of the compound B is generally 0. 0 relative to the total amount of the polymer layer containing the compound B. 1 to 20% by weight, preferably 1 to 10% by weight, more preferably 2 to 8% by weight. When compound B is contained in two or more polymer layers, the content of compound B may be in the above range in each polymer layer.

  In each polymer layer (for example, the first polymer layer, the second polymer layer, or the third polymer layer), the total content of the phosphoric acid compound, the phosphonic acid compound, and the compound B is usually based on the total amount of each polymer layer. It is 0.5 to 40 weight%, Preferably it is 2 to 30 weight%, More preferably, it is 5 to 20 weight%.

  When the polymer layer is a multilayer type, the first polymer layer 41, the second polymer layer 42, and the third polymer layer 43 are each independently a single layer type using a predetermined component and a polymer (or a precursor thereof). It can be produced by the same method as that for the polymer layer (first polymer layer) 41 of the polymer layer.

  The thickness of each polymer layer (the first polymer layer, the second polymer layer, or the third polymer layer) is preferably as thick as possible from the viewpoint of leaching of each component. Is usually 1 to 100 μm, preferably 1 to 50 μm, more preferably 5 to 40 μm.

When one or more polymer layers (for example, reference numerals 41 to 43) are formed on the plating layer 2, an insulating layer may be formed between the plating layer 2 and the polymer layer. The insulating layer means an insulating layer (particularly a polymer layer) having a volume resistivity of 10 ¹² Ω · cm or more. By forming the insulating layer, it is possible to prevent moisture that has entered from the nanofiber from coming into direct contact with the metal. The insulating layer does not contain a component of the restorative agent, and can usually be produced by a material and method within the same range as the polymer layer (first polymer layer) 41 of the single-layer polymer layer. The thickness of the insulating layer is usually 1 to 100 μm, and preferably 1 to 50 μm, more preferably 5 to 40 μm from the viewpoint of insulation.

  In the restorative 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 restoration agent of the present invention does not necessarily have to be a plating base material to which repairability is imparted, and is useful for the metal base material 1 that does not have the plating layer 2. Therefore, the repairable plating substrate of the present invention may not have a plating layer. When the repairable plating substrate of the present invention does not have a plating layer, it can also be referred to as a “repairable metal substrate”. The structure of the “restorable metal substrate” of the present invention has no plating layer and has the above-described single layer type or multilayer type polymer layer formed directly on the surface of the metal substrate 1, The structure is the same as that of the repairable plating substrate. When the restoration agent of the present invention exhibits the restorability is the metal substrate 1 that does not have a plating layer, and the restorability plating substrate of the present invention is a repairable metal substrate that does not have a plating layer. In some cases, the restorative agent of the present invention further comprises Compound B as an essential component.

(material)
The following materials were used.
・ Epoxy resin (Hypon 20 Decro Gray; manufactured by Nippon Paint Co., Ltd., curing agent = polyamidoamine, coating liquid: curing agent = 85: 15 (weight ratio))
Carbon steel plate (high tensile material) (12 mm x 12 mm) (content ratio: carbon 0.5 wt%, silicon 0.02 wt%, manganese 0.2 wt%, phosphorus 0.1 wt%, sulfur 0.1 wt% , Balance: iron)
・ Zinc sulfate (hereinafter sometimes abbreviated as “Zn”)
Cellulose nanofiber (Serish; manufactured by Daicel, average fiber length: 0.3 mm, average fiber diameter: 0.2 μm) (hereinafter sometimes abbreviated as “CNF”)
・ Sodium dihydrogen phosphate (hereinafter sometimes abbreviated as “PO ₄ ”)
ATMP sodium salt (hereinafter sometimes abbreviated as “AT”)

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

Formation of Insulating Layer 40 An epoxy resin was coated on a carbon steel plate by a bar coating method so that the coating thickness (after drying) was 20 μm, and was cured by holding at 80 ° C. for 3 hours to form the insulating layer 40.

-Formation of the 1st polymer layer 41 Zinc sulfate and the cellulose nanofiber were mixed with the spatula, the mixture was added to the epoxy resin, and it stirred and deaerated with the stirrer, and prepared the 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 was cured by holding at 80 ° C. for 3 hours to form the first polymer layer 41.

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

-Formation of the topcoat layer 60 The topcoat layer 60 was formed in the 2nd polymer layer 42 by the method similar to the formation method of the insulating layer 40. The top coat layer 60 is a layer for preventing elution of the repair agent from other than scratches to be formed later.

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

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

(Example 2)
A test piece having a schematic cross-sectional structure shown in FIG. 4 was produced. Details are as follows.
A test piece was produced in the same manner as in Example 1 except that the second polymer layer 42 was not formed and that the following coating liquid was used to form the first polymer layer 41.
-Coating liquid of first polymer layer 41 Zinc sulfate, sodium dihydrogen phosphate, ATMP sodium salt and cellulose nanofiber are mixed with a spatula, the mixture is added to an epoxy resin, and the mixture is stirred and degassed with a stirrer. A liquid was prepared. The contents of zinc sulfate, sodium dihydrogen phosphate, ATMP sodium salt and cellulose nanofiber are 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 produced. Details are as follows.
A test piece was produced in the same manner as in Example 2 except that cellulose nanofibers were not used to form the first polymer layer 41.

(Reference Example 1)
A test piece having a schematic cross-sectional structure shown in FIG. 6 was produced. Details are as follows.
A test piece was produced in the same manner as in Example 2 except that zinc sulfate, sodium dihydrogen phosphate, ATMP sodium salt, and cellulose nanofiber were not used to form the first polymer layer 41.

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

Example 4
A test piece having a cross-sectional structure similar to the schematic cross-sectional structure shown in FIG. 1G was manufactured except that an insulating layer was formed instead of the plating layer 2 and scratches were applied. Details are as follows.

-Formation of an insulating layer By the method similar to the formation method of the insulating layer of Example 1, the insulating layer was formed in the carbon steel plate.

-Formation of the 1st polymer layer 41 Zinc sulfate and the cellulose nanofiber were mixed with the spatula, the mixture was added to the epoxy resin, and it stirred and deaerated with the stirrer, and prepared the 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 was cured by holding at 80 ° C. for 3 hours to form the first polymer layer 41.

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

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

-Formation of topcoat layer The topcoat layer was formed in the 3rd polymer layer 43 by the method similar to the formation method of the topcoat layer of Example 1. FIG.

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

(Example 5)
The coating liquid for the third polymer layer was used as the coating liquid for the second polymer layer, and the coating liquid for the second polymer layer was used as the coating liquid for the third polymer layer. A test piece was produced in the same manner as in Example 4 except that.

(Evaluation 1)
In the electrochemical measuring apparatus 50 shown in FIG. 8, the test piece is immersed in the corrosive solution 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-repairability of the test piece is measured. evaluated. As the corrosive solution 52, 0.5% by weight of saline was kept at 35 ° C. and saturated with air. 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).

  9A to 9B show changes with time in the polarization resistance of each test piece. In these figures, the vertical axis represents polarization resistance and the horizontal axis represents immersion time. This indicates that the higher the polarization resistance, the less likely the corrosion reaction occurs at the scratch. In addition, the graph which shows a time-dependent change of the test piece of Example 4 and 5 was abbreviate | omitted. For Examples 4 and 5, the average value of polarization resistance and its error range (maximum value and minimum value) in Evaluation 2 described later are shown in FIG.

  When only epoxy resin was coated in Reference Example 1 (Plain), high polarization resistance was exhibited at the initial stage of immersion, but the resistance value gradually decreased thereafter. It is thought that corrosion has progressed on the exposed surface of the steel plate at the scratch.

From the comparison between Example 1 and Comparative Example 1 and the comparison between Example 2 and Comparative Example 2, it was revealed that the inclusion of CNF increases the polarization resistance and suppresses corrosion more sufficiently. It is considered that CNF promoted leaching from the layers of Zn, PO ₄ and AT, and a protective film (restoration film) was more effectively formed on the exposed surface of the steel plate at the scratched part.

From the comparison between Example 1 and 3 and Example 2, the polymer layer is divided into two layers and divided into a Zn and CNF layer and a PO ₄ , AT and CNF layer. It became clear that it became high. When Zn, PO ₄ and AT are contained separately in a Zn layer and a PO ₄ and AT layer, the reactions of the above reaction formulas (I) and (II) in the layer are suppressed, and Zn, It is considered that the exudation from the PO ₄ and AT layers was further sufficiently promoted by CNF.

From the comparison between Example 1 and Example 3, the corrosion suppression effect is more sufficiently achieved by using two polymer layers and positioning the Zn and CNF layers below the PO ₄ , AT and CNF layers. It became clear that it became high. As shown in FIG. 10, a Zn-rich layer that is more effective in inhibiting corrosion is more easily formed on the exposed surface of the metal substrate than a layer made of a composite product of Zn + PO ₄ + AT, and therefore, the corrosion-inhibiting effect is more effective. It is thought that it will be much higher.

In Example 1, when a scanning electron microscope (SEM) photograph of the exposed surface of the steel sheet in the scratched part after 48 hours of immersion time was taken (FIG. 11A), a product having a diameter of about 1 μm covered the exposed surface. Was confirmed. In addition, 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 encircled portion by the white line in FIG. 11A. FIG. 11H is an enlarged photograph of a portion surrounded by a white line in FIG. 11B. FIG. 11I is an enlarged photograph of a portion surrounded by a white line in FIG. 11E. FIG. 11J is an enlarged photograph of a portion surrounded by a white line in FIG. 11C. FIG. 11K is an enlarged photograph of the encircled portion by the white line in FIG. 11D.
11A to 11K (actual: color copy) and photographs (actual: color copy) of FIGS. 12A to 12F, 13A to 13F, and 14A to 14E described later are used as reference material (reference photograph) 1. Submit in the property submission form.

From FIGS. 11G, 11H, and 11I, Fe and O are detected in different regions. This shows 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. This shows 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 part when the immersion time was 3 hours was taken (FIG. 12A). In addition, 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 part when the immersion time was 48 hours was taken (FIG. 13A). In addition, an element mapping image was obtained by an energy dispersive X-ray analyzer (EDS). 13B to 13F are mapping images of the 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 at the scratched part when the immersion time was 48 hours was taken (FIG. 14A). In addition, 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)
Reproducibility was verified for Examples 1 to 5 and Reference Example 1. In each of the examples / reference examples, three or more test pieces were prepared, the AC impedance was measured for 48 hours by the same method as in Evaluation 1, and the polarization resistance was measured at 48 hours of immersion. 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 represents polarization resistance (Ω · cm ² ).

  The restoration | repair agent of this invention is useful in the field | area of articles | goods (for example, metal products, such as a motor vehicle, household appliances, and metal building materials) by which suppression of corrosion is calculated | required.

1: Metal base material 2: Plating layer 10: Plating base material 13: Defect (scratch)
14: Protective film 40: Insulating layer 41: First polymer layer 42: Second polymer layer 43: Third polymer layer

Claims (26)

A restoration agent for a plating substrate having a plating layer containing a metal A having a higher ionization tendency than the metal constituting the metal substrate on the surface of the metal substrate,
A restorative agent comprising a phosphoric acid compound, a phosphonic acid compound and nanofibers. The nanofiber is included in an amount of 1 to 200 parts by weight with respect to 100 parts by weight of the total amount of the phosphoric acid compound and the phosphonic acid compound.
The restoration agent according to claim 1, wherein the phosphoric acid compound and the phosphonic acid compound are contained in a weight ratio of 10/90 to 90/10. The plating substrate has a defect reaching the metal substrate;
The nanofiber promotes the leaching of the phosphate compound and the phosphonate compound to the surface of the exposed metal substrate,
The restoration agent according to claim 1 or 2, wherein the metal A, the phosphoric acid compound, and the phosphonic acid compound having a high ionization tendency form a protective film on the surface of the exposed metal substrate. One or more polymer layers are formed on the plating layer,
The phosphoric acid compound and the phosphonic acid compound are each independently contained in a layer selected from the group consisting of the one or more polymer layers, and the nanofiber is composed of the phosphoric acid compound or the phosphonic compound. The restoration | repair agent in any one of Claims 1-3 contained in the polymer layer containing at least one of an acid compound. The restoration agent further includes a compound containing a metal B having a higher ionization tendency than a metal constituting the metal base material,
The compound containing metal B having a high ionization tendency is included in a layer selected from the group consisting of the one or more polymer layers, and the nanofiber contains the metal B having a high ionization tendency. Contained in the polymer layer containing the compound,
The restoration agent according to claim 4, wherein the compound containing metal B having a high ionization tendency is included 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. Two or more polymer layers are formed on the plating layer,
The compound containing 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. The repair agent according to claim 5. A first polymer layer and a second polymer layer are sequentially formed on the plating layer,
The compound containing metal B having a high ionization tendency is included in one polymer layer of the first polymer layer and the second polymer layer,
The restoration agent according to claim 6, wherein the phosphoric acid compound and the phosphonic acid compound are contained in the other polymer layer. The compound containing metal B having a high ionization tendency is included in the first polymer layer,
The restoration agent according to claim 7, wherein the phosphoric acid compound and the phosphonic acid compound are contained in the second polymer layer. Three polymer layers are formed on the plating layer,
The compound containing metal B having a high ionization tendency is included in one polymer layer among the three polymer layers,
The phosphoric acid compound and the phosphonic acid compound are respectively contained in different polymer layers among the two polymer layers other than the polymer layer containing the compound containing the metal B having a high ionization tendency. 6. The repair agent according to 6. A first polymer layer, a second polymer layer, and a third polymer layer are sequentially formed on the plating layer,
The compound containing metal B having a high ionization tendency is included in the first polymer layer,
The phosphoric acid compound is contained in one polymer layer of the second polymer layer or the third polymer layer,
The restoration | repair agent of Claim 9 in which the said phosphonic acid compound is contained in the other polymer layer. In the polymer layer including the compound containing the metal B having a high ionization tendency, the compound containing the metal B having the high ionization tendency is included in an amount of 1 to 20% by weight with respect to 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 included in an amount of 0.1 to 20% by weight based on the total amount of the polymer layer.
The restoration agent according to any one of claims 5 to 10, wherein in the polymer layer including the nanofiber, the nanofiber is included in an amount of 0.1 to 20 wt% with respect to the total amount of the polymer layer. The phosphate compound is an inorganic phosphate compound,
The inorganic phosphate compound is one or more compounds selected from the group consisting of phosphoric acid (H ₃ PO ₄ ) and phosphate,
The phosphonic acid compound is an organic phosphonic acid compound,
The organic phosphonic acid compound is one or more compounds selected from the group consisting of nitrogen-containing phosphonic acid compounds and salts thereof;
The said nanofiber is a restoration | repair agent in any one of Claims 1-11 which is a cellulose nanofiber. The metal substrate is a steel plate;
The metals A and B having a high ionization tendency are each independently one or more metals selected from the group consisting of zinc, aluminum, magnesium and zirconium;
The restoration agent according to claim 1, wherein the plating layer is formed by an impact plating method. A repairable plating substrate having a plating layer containing a metal A having a higher ionization tendency than the metal constituting the metal substrate on the surface of the metal substrate,
A restorative plating substrate comprising a restorative comprising a phosphoric acid compound, a phosphonic acid compound and nanofibers. The nanofiber is included in an amount of 1 to 200 parts by weight with respect to 100 parts by weight of the total amount of the phosphoric acid compound and the phosphonic acid compound.
The repairable plating base material according to claim 14, wherein the phosphoric acid compound and the phosphonic acid compound are contained in a weight ratio of 10/90 to 90/10. The plating substrate has a defect reaching the metal substrate;
The nanofiber promotes the leaching of the phosphate compound and the phosphonate compound to the surface of the exposed metal substrate,
The repairable plating base material according to claim 14 or 15, wherein the metal A, the phosphoric acid compound and the phosphonic acid compound having a high ionization tendency form a protective film on the surface of the exposed metal base material. One or more polymer layers are formed on the plating layer,
The phosphoric acid compound and the phosphonic acid compound are each independently contained in a layer selected from the group consisting of the one or more polymer layers, and the nanofiber is composed of the phosphoric acid compound or the phosphonic compound. The repairable plating base material according to any one of claims 14 to 16, which is contained in a polymer layer containing at least one of acid compounds. The restoration agent further includes a compound containing a metal B having a higher ionization tendency than a metal constituting the metal base material,
The compound containing metal B having a high ionization tendency is included in a layer selected from the group consisting of the one or more polymer layers, and the nanofiber contains the metal B having a high ionization tendency. Contained in the polymer layer containing the compound,
18. The restorative plating according to claim 17, wherein the compound containing metal B having a high ionization tendency is included 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. Base material. Two or more polymer layers are formed on the plating layer,
The compound containing 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. The repairable plating base material according to claim 18. A first polymer layer and a second polymer layer are sequentially laminated on the plating layer,
The compound containing metal B having a high ionization tendency is included in one polymer layer of the first polymer layer and the second polymer layer,
The repairable plating base material according to claim 19, wherein the phosphoric acid compound and the phosphonic acid compound are contained in the other polymer layer. The compound containing metal B having a high ionization tendency is included in the first polymer layer,
21. The repairable plating substrate according to claim 20, wherein the phosphoric acid compound and the phosphonic acid compound are contained in the second polymer layer. Three polymer layers are formed on the plating layer,
The compound containing metal B having a high ionization tendency is included in one polymer layer among the three polymer layers,
The phosphoric acid compound and the phosphonic acid compound are respectively contained in different polymer layers among the two polymer layers other than the polymer layer containing the compound containing the metal B having a high ionization tendency. 19. The restorative plating base material according to 19. A first polymer layer, a second polymer layer, and a third polymer layer are sequentially laminated on the plating layer,
The compound containing metal B having a high ionization tendency is included in the first polymer layer,
The phosphoric acid compound is contained in one polymer layer of the second polymer layer or the third polymer layer,
The restorative plating base material according to claim 22, wherein the phosphonic acid compound is contained in the other polymer layer. In the polymer layer including the compound containing the metal B having a high ionization tendency, the compound containing the metal B having the high ionization tendency is included in an amount of 1 to 20% by weight with respect to 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 included in an amount of 0.1 to 20% by weight based on the total amount of the polymer layer.
The restorative plating according to any one of claims 18 to 23, wherein in the polymer layer including the nanofiber, the nanofiber is included in an amount of 0.1 to 20 wt% with respect to the total amount of the polymer layer. Base material. The phosphate compound is an inorganic phosphate compound,
The inorganic phosphate compound is one or more compounds selected from the group consisting of phosphoric acid (H ₃ PO ₄ ) and phosphate,
The phosphonic acid compound is an organic phosphonic acid compound,
The organic phosphonic acid compound is one or more compounds selected from the group consisting of nitrogen-containing phosphonic acid compounds and salts thereof;
The repairable plating base material according to any one of claims 14 to 24, wherein the nanofiber is a cellulose nanofiber. The metal substrate is a steel plate;
The metals A and B having a high ionization tendency are each independently one or more metals selected from the group consisting of zinc, aluminum, magnesium and zirconium;
The repairable plating base material according to any one of claims 14 to 25, wherein the plating layer is formed by an impact plating method.