WO2008075738A1 - Surface pretreatment fluid for the metal to be coated by cationic electrodeposition - Google Patents

Abstract

The invention provides a zirconium ion containing surface pretreatment fluid for the metal to be coated by cationic electrodeposition which makes it possible to develop satisfactory throwing power in the electrodeposition and is excellent in corrosion inhibition performance. The invention relates to a surface pretreatment fluid for the metal to be coated by cationic electrodeposition which contains zirconium ions and tin ions and has a pH of 1.5 to 6.5, wherein the zirconium ion concentration is 10 to 10000ppm and the content ratio by mass of tin ion to zirconium ion is 0.005 to 1. The fluid may further contain a polyamine, copper ion, fluoride ion, or a chelate compound.

Description

 Specification

 Metal surface treatment solution for cationic electrodeposition coating

 Technical field

 The present invention relates to a metal surface treatment liquid, particularly a metal surface treatment liquid suitable for cationic electrodeposition coating, and a metal surface treatment method.

 Background art

 [0002] Conventionally, surface treatment has been performed to impart corrosion resistance to various metal substrates. In particular, zinc phosphate treatment has been generally used for metal substrates constituting automobiles. However, this zinc phosphate treatment has a problem that sludge is generated as a by-product. For this reason, there is a demand for next-generation surface treatment that does not use zinc phosphate, and surface treatment with zirconium ions is one of them (for example, see Patent Document 1).

).

 [0003] On the other hand, a cationic base electrodeposition coating is applied after a surface treatment to a metal base material constituting an automobile, which requires high anticorrosion properties. The reason why cationic electrodeposition coating is applied is that the coating film obtained by force thioion electrodeposition coating has excellent anticorrosion properties and that it is applied to every corner of an automobile body with a complex shape. It has the property of being able to do so-called “climbing performance”!

 [0004] However, recently, when cationic electrodeposition coating is performed on a metal base material that has been surface-treated with the zirconium ions, it is difficult to obtain a sufficient effect on the throwing power! For example, it has been found that the throwing power for cold-rolled steel sheets may not be sufficient. Thus, when cationic electrodeposition is applied, sufficient corrosion resistance cannot be obtained unless the throwing power is sufficient.

 Patent Document 1: Japanese Patent Application Laid-Open No. 2004-218070

 Disclosure of the invention

 Problems to be solved by the invention

[0005] The present invention is based on zirconium ions, which can exhibit sufficient throwing power and have excellent anticorrosion properties when cationic electrodeposition is applied to a surface-treated metal substrate. The object is to provide a surface treatment.

 Means for solving the problem

[0006] The present invention is as follows.

 (1) A metal surface treatment solution for cationic electrodeposition coating containing zirconium ions and tin ions and having a pH of 1 · 5 to 6.5, wherein the concentration of the zirconium ions is 10 to; ΙΟΟΟΟρ pm, and The concentration ratio of tin ions to zirconium ions is 0.005 in terms of mass.

A metal surface treatment solution for cationic electrodeposition coating, which is ~!

[0007] (2) A metal surface treatment solution for cationic electrodeposition coating further comprising a polyamine compound as the metal surface treatment solution for cationic electrodeposition coating (1).

[0008] (3) A metal surface treatment solution for cationic electrodeposition coating further comprising copper ions as the metal surface treatment solution for cationic electrodeposition coating of (1) to (2) above.

[0009] (4) The metal surface treatment liquid for cationic electrodeposition coating described in (1) to (3) above further contains fluorine, and the amount of free fluorine ions when the pH is 3.0 is 0. . ~! Power of 50ppm Metal surface treatment solution for thione electrodeposition coating.

[0010] (5) A metal surface treatment solution for cationic electrodeposition coating further comprising a chelate compound as the metal surface treatment solution for cationic electrodeposition coating of (1) to (4) above.

[0011] (6) A metal surface treatment solution for cationic electrodeposition coating in which the chelate compound is sulfonic acid as the metal surface treatment solution for cationic electrodeposition coating in (5).

[0012] (7) A metal surface treatment solution for cationic electrodeposition coating further comprising an oxidizing agent as the metal surface treatment solution for cationic electrodeposition coating of (1) to (6) above.

[0013] (8) The metal surface treatment solution for cationic electrodeposition coating according to any one of (1) to (7), further comprising aluminum ions and / or indium ions.

[0014] (9) A metal surface treatment method comprising a step of performing a surface treatment on a metal substrate using the metal surface treatment liquid for cationic electrodeposition coating described in (1) to (8) above.

[0015] (10) A metal substrate on which a film is formed by surface treatment, which is obtained by the metal surface treatment method of (9).

[0016] (11) A metal substrate in which the element ratio of zirconium / tin in the film formed on the metal substrate of (10) is 1/10 to 10/1 in terms of mass. [0017] (12) A step of performing a surface treatment on a metal substrate using the metal surface treatment liquid for cationic electrodeposition coating according to (1) to (8) above, and the metal substrate subjected to the surface treatment A cationic electrodeposition coating method including a step of applying cathodic electrodeposition coating to a material.

 [0018] (13) A cationic electrodeposition-coated metal substrate obtained by the cationic electrodeposition coating method of (12) above.

 That is, the metal surface treatment solution for cationic electrodeposition coating of the present invention is a chemical conversion treatment solution containing zirconium ions and tin ions and having a pH of 1.5 to 6.5, and the concentration of the zirconium ions is The content of tin ions with respect to the zirconium ions is 0.0005 to 1 in terms of mass. Furthermore, a polyamine compound, copper ion, fluorine ion, chelate compound, oxidizing agent, and antifungal agent may be included. When fluorine ions are included, the amount of free fluorine ions when the pH is 3.0 may be 0.;!-50 ppm.

 [0020] The metal surface treatment method of the present invention includes a step of performing a surface treatment on a metal substrate using the above metal surface treatment liquid.

 [0021] The surface-treated metal substrate of the present invention is formed with a film obtained by the previous surface treatment. The element ratio of zirconium / tin in the film may be 1/10 to 10/1 in terms of mass.

 [0022] The cationic electrodeposition coating method of the present invention includes a step of performing a surface treatment on a metal substrate using the above-described metal surface treatment solution, and a cation for the metal substrate subjected to the surface treatment. And a process of performing electrodeposition coating.

 [0023] The metal substrate coated with cationic electrodeposition according to the present invention is obtained by the previous coating method.

 [0024] The metal surface treatment liquid for cationic electrodeposition coating of the present invention contains tin ions in addition to zirconium ions, so that it can be used when the cationic electrodeposition coating is performed after forming a chemical conversion film with this treatment liquid. This is considered to improve the performance. Although the reason is not clear, it can be considered as follows.

[0025] That is, when zirconium ions are used alone, the formation of the oxide film is considered to be performed simultaneously with the etching of the metal substrate in an acidic atmosphere. Toko However, on the cold-rolled steel sheet, there are segregated materials of compounds containing silicon and carbon in addition to silica, and such portions are difficult to be etched. For this reason, the film formation by the zirconium oxide is not performed uniformly, and there is a portion where the film is not formed. Since the current flow is different between the part where the film is formed and the part where the film is not formed, electrodeposition is not performed uniformly. As a result, it is considered that sufficient throwing power cannot be obtained.

 [0026] Here, when tin ions are present, it is considered as follows. Tin ions are less susceptible to steel plate effects than zirconium ions, so it is easy to form an oxide film on the substrate. Although tin ions do not specifically form a film on a portion where zirconium ions are difficult to precipitate, tin ions do not form an oxide film on a specific portion. As a result, the tin ion forms a film by compensating for the part where the zirconium ion could not be formed.

[0027] The metal surface treatment liquid for cationic electrodeposition coating of the present invention can improve the adhesion to the cationic electrodeposition coating film by containing a polyamine compound, and as a result, the conditions are more severe. The SDT test can also be cleared. Moreover, the metal surface treatment liquid for cationic electrodeposition coating of the present invention can improve corrosion resistance by containing copper ions. The reason is not clear, but it is thought that some interaction is acting between copper and zirconium during film formation. Furthermore, when the metal surface treatment liquid for cationic electrodeposition coating of the present invention contains a large amount of metal other than zirconium, a zirconium oxide film can be stably formed by including a chelate compound. This is presumably because the chelate compound captures metal ions that are more likely to precipitate than zirconium.

 Brief Description of Drawings

 FIG. 1 is a perspective view showing an example of a box used when evaluating throwing power.

 FIG. 2 is a drawing schematically showing the evaluation of throwing power.

 Explanation of symbols

[0029] 1, 2, 3, 4 ··· Test plate, 5 · · Through hole, 10 · · Box, 20 · · Electrodeposition coating container, 21 · · · Counter electrode Form for carrying out the invention [0030] The metal surface treatment solution for cationic electrodeposition coating of the present invention is a chemical conversion treatment solution containing zirconium ions and tin ions and having a pH of 1.5 to 6.5.

 [0031] The concentration of the zirconium ions is 10 to 10,000 ppm. If it is less than lOppm, the precipitation of the dinoleum oxide film is not sufficient, so that sufficient corrosion resistance cannot be obtained, and if it exceeds lOOOOppm, the deposition amount of the zirconium film does not increase, and the adhesion of the film decreases to prevent corrosion such as SDT. The performance may be inferior, and an effect commensurate with it cannot be obtained. Preferred lower and upper limits are lOOppm and 500ppm, respectively.

[0032] It should be noted that, in the present specification, the notation of the concentration of metal ions is the metal element-concentrated concentration in which, when the complex is an oxide, the focus is only on the metal atom in the complex. It shall be expressed as For example, complex ion ZrF ² (molecular weight 205)

 6

 The metal element equivalent concentration of ruconium is calculated as 44 ppm by the calculation of 100 X (91/205). In addition, in the metal surface treatment liquid for cationic electrodeposition coating of the present invention, a part of the metal compound (a zirconium compound, a tin compound, a copper compound or other metal compound) exists in a nonionic state such as an oxide. However, the ratio is very small, and is considered to exist as a metal ion. Therefore, the metal ion concentration in this specification is the metal ion concentration when 100% dissociates and exists as a metal ion regardless of whether or not a part of the metal ion exists as non-ion! .

[0033] The tin ion contained in the metal surface treatment solution for cationic electrodeposition coating of the present invention is preferably a divalent cation. At other valences, the intended effect may not be obtained. However, the tin ion is not limited to a divalent cation, and any tin ion that can be deposited on a metal substrate can be used in the present invention. For example, when a tin ion forms a complex, it may be a tetravalent cation. This can also be used in the present invention. The concentration of the tin ions is 0.005 to 1 in terms of mass with respect to the concentration of the zirconium ions. If it is less than 0.005, the effect of addition cannot be obtained, and if it exceeds 1, zirconium may be difficult to precipitate. Preferred lower and upper limits are 0.02 and 0.2, respectively. However, since the effect of the present invention may not be obtained if the total amount of zirconium ions and tin ions is too small, the sum of the concentration of the above-mentioned zirconium ions and the concentration of tin ions in the metal surface treatment liquid of the present invention. However, it is preferable that it is 15ppm or more. [0034] The content of tin ions in the metal surface treatment solution of the present invention is preferably! ~ LOOppm. If it is less than lppm, the precipitation of tin on the portion where dinoleconium cannot form a film becomes insufficient, and the anticorrosion properties such as SDT tend to be poor. If it exceeds lOOppm, a zirconium film will be deposited and the corrosion resistance and paint appearance will tend to be poor. The content is more preferably 5 to 100 ppm, and further preferably 5 to 50 ppm.

 The metal surface treatment liquid for cationic electrodeposition coating of the present invention has a pH of 1.5 to 6.5. If it is less than 1.5, the metal substrate is not sufficiently etched, so that the coating amount is reduced and sufficient corrosion resistance cannot be obtained. In addition, the stability of the processing solution may not be sufficient. On the other hand, if it exceeds 6.5, etching may be excessive and sufficient film formation may not be possible, or the coating amount and film thickness may be uneven, which may adversely affect the appearance of the coating. The lower limit value and the upper limit value are preferably 2.0 and 5.5, respectively, and more preferably 2.5 and 5.0.

[0036] The metal surface treatment liquid for cationic electrodeposition coating of the present invention may further contain a polyamine compound in order to enhance the adhesion to the cationic electrodeposition coating film formed after the surface treatment. The polyamine compound used in the present invention is considered to have an essential meaning in that it is an organic molecule having an amino group. That is, although the following is speculated, it is considered that amino groups are incorporated into the film by chemical action with zirconium oxide deposited as a film on the metal substrate and the metal substrate. In addition, it is considered that the polyamine compound that is an organic molecule contributes to adhesion with a coating film provided on the metal substrate on which the coating film is formed. Therefore, when a polyamine compound which is an organic molecule having an amino group is used, the adhesion between the metal substrate and the coating film is remarkably improved, and excellent corrosion resistance can be obtained. Examples of the polyamine compound include hydrolyzed condensates of aminosilanes, polyvinylenoamines, polyallylamamines, and water-soluble phenol resins having amino groups. An aminosilane hydrolyzed condensate is preferable because the amount of amine can be adjusted freely. Accordingly, the metal surface treatment solution for cationic electrodeposition coating of the present invention includes, for example, a metal surface treatment solution for cationic electrodeposition coating containing a hydrolytic condensate of zirconium ions, tin ions, and aminosilanes, zirconium ions, tin ions. And including polyallylamine Examples of the metal surface treatment solution for cationic electrodeposition coating include a metal surface treatment solution for cationic electrodeposition coating containing a water-soluble phenolic resin having zirconium ions, tin ions, and amino groups. Moreover, you may contain the fluorine mentioned later in these metal surface treatment liquids for cationic electrodeposition coating.

 [0037] The aminosilane hydrolyzed condensate is obtained by hydrolytic condensation of an aminosilane compound. Examples of the aminosilane compound include butyltrichlorosilane, vinyltrimethoxysilane, butyltriethoxysilane, 2- (3,4 epoxy cyclohexylenopropylenolemethinolegoxysilane, and 3-glycidoxypropinoretriethoxysilane. P

N-2- (Aminoethyl) 3 aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3 aminopropyltrimethoxysilane, N-2- (aminoethyl) 3 aminopropyltriethoxysilane, 3- Aminopropyltrimethoxysilane, 3-Aminopropyltriethoxysilane, 3-Triethoxysilyl N- (l, 3-dimethyl-propylidene) propylamine, N Phenoluyl 3-Aminopropyl trimethoxysilane, N — (Buylbenzyl) 2 aminoethyl 1 3 aminopropyltrimethoxysilane hydrochloride, 3 ureidopropyl

Pyr) tetrasulfide, 3-isocyanate propyltriethoxysilane, and other silane coupling agents having an amino group. In addition, commercially available products such as “K ΒΜ-403”, “ΚΒΜ-602”, “ΚΒΜ-603”, “ΚΒΕ-603”, “ΚΒΜ-903”, “Κ BE-903”, “ΚΒΕ— “9103”, “ΚΒΜ-573”, “ΚΒΡ-90” (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), “XS1003” (trade names, manufactured by Chisso Corporation) and the like can be used.

[0038] Hydrolysis condensation of the aminosilane can be carried out by methods well known to those skilled in the art. Specifically, it can be carried out by adding water necessary for hydrolyzing an alkoxysilyl group to at least one aminosilane compound, and heating and stirring as necessary. . The degree of condensation can be controlled by the amount of water used.

[0039] A higher degree of condensation of the aminosilane hydrolyzed condensate is preferred because zirconium tends to be taken into the oxide when it precipitates as an oxide. For example, in the total amount of aminosilane, the proportion of aminosilanes in the dimer or higher is preferably 40% or more, more preferably 50% or more, more preferably 70% or more, in terms of mass. More preferably, it is 80% or more. For this reason, when aminosilane is reacted in a hydrolysis-condensation reaction, the reaction should be performed under conditions where aminosilane is more easily hydrolyzed and condensed, such as using an aqueous solvent containing a catalyst such as alcohol and acetic acid. Is preferred. In addition, a hydrolysis condensate having a high degree of condensation can be obtained by reacting under conditions where the aminosilane concentration is relatively high. Specifically, it is preferable to hydrolyze and condense the aminosilane concentration in the range of 5% by mass or more and 50% by mass or less. The degree of condensation can be determined by ²⁹ Si-NMR measurement.

[0040] As the polybulamine and polyallylamin, it is possible to use commercially available products. Examples of polyburamine include “PVAM-0595B” (trade name, manufactured by Mitsubishi Chemical), and examples of polyallylamin include “PAA-01”, ΓΡΑΑ-IOCJ, “PAA—H-10C”, “PAA—D— “41HC1” (all trade names, manufactured by Nitto Boseki Co., Ltd.) etc.

 [0041] The molecular weight of the polyamine compound is preferably 150 to 500,000. If it is less than 150, a chemical conversion film having sufficient adhesion cannot be obtained! If the molecular weight exceeds 500,000, film formation may be hindered. Further preferred lower and upper limits are 5000 and 70000, respectively. If the amount of amino group is too large, the polyamine compound may adversely affect the film. If the amount is too small, the effect of improving adhesion to the film due to the amino group is difficult to obtain. 0.1 to 1 mmol and 17 mmol or less primary and / or secondary amino group preferably 3 to 15 mmol or less primary and / or secondary amino group per lg Is preferred.

[0042] The number of moles of primary and / or secondary amino groups per lg of the solid content of the polyamine compound can be determined by the following mathematical formula (1). [0043] country

 Amine group amount = (mX-nY) / (m + n) ...

 (In the formula, when the solid mass ratio of the polyamine compound and the compound having the functional group A and / or the functional group B is m: n, the compound having the functional group A and / or the functional group B. When the number of millimoles of functional group A and / or functional group B per lg is Y and the compound having the functional group A and / or functional group B is not contained in the metal surface treatment composition, X represents the number of millimoles of primary and / or secondary amino groups contained per lg of compound).

 [0045] The content of the polyamine compound in the metal surface treatment liquid for cationic electrodeposition coating of the present invention is 1 to 200% based on the metal equivalent mass of zirconium contained in the surface treatment liquid. it can. If it is less than 1%, the intended effect cannot be obtained, and if it exceeds 200%, the skin film may not be sufficiently formed. As the upper limit of the content, 120% is more preferable, 100% is more preferable, 80% is more preferable, and 60% is more preferable.

 [0046] The metal surface treatment liquid for cationic electrodeposition coating of the present invention may contain copper ions in order to further improve the corrosion resistance. The amount of the copper ions is preferably a concentration that is 10 to 100% with respect to the concentration of the tin ions. If it is less than 10%, the intended effect may not be obtained, and if the concentration of tin ions is exceeded, zirconium may be precipitated as in the case of tin ions. Examples of the metal surface treatment solution for cationic electrodeposition coating of the present invention include a metal surface treatment solution for cationic electrodeposition coating containing zirconium ions, tin ions and copper ions. In this case, it is possible to further contain fluorine ions described later, and the polyamine compound can be contained.

[0047] The metal surface treatment liquid for cationic electrodeposition coating of the present invention preferably contains fluorine ions. Since the concentration of fluoride ion varies with pH, the amount of free fluoride ion at a specific pH is specified. In the present invention, the amount of free fluorine ions when the pH is 3.0 is 0. !!-50 ppm. If it is less than lppm, the metal substrate is not sufficiently etched, so the amount of the coating is reduced and sufficient corrosion resistance cannot be obtained. In addition, the stability of the treatment liquid may not be sufficient. If it exceeds 50 ppm, etching may be excessive and sufficient film formation may not be possible, and the coating amount and film thickness may be uneven, which may adversely affect the appearance of the coating. Like The lower and upper limits are 0.5 ppm and l Oppm, respectively. Examples of the metal surface treatment liquid for cationic electrodeposition coating of the present invention include a metal surface treatment liquid for cationic electrodeposition coating containing zirconium ions, tin ions, and fluorine ions.

 [0048] The metal surface treatment liquid for cationic electrodeposition coating of the present invention may contain a chelate compound. By including the chelate compound, precipitation of metals other than zirconium in the treatment liquid can be suppressed, and a zirconium oxide film can be stably formed. Examples of the chelate compound include amino acids, aminocarboxylic acids, phenol compounds, aromatic carboxylic acids, sulfonic acids, ascorbic acids and the like. Incidentally, carboxylic acids having a hydroxyl group such as citrate and darconic acid, which have been conventionally known as chelating agents, cannot sufficiently exhibit their functions in the present invention.

 [0049] As the amino acid, in addition to various natural amino acids and synthetic amino acids, amino acids having at least one amino group and at least one acid group (such as a carboxyl group or a sulfonic acid group) in one molecule should be widely used. Can do. Among them, alanine, glycine, dartamic acid, aspartic acid, histidine, phenylalanin, asparagine, arginine, glutamine, cysteine, leucine, lysine, proline, serine, tryptophan, valine, tyrosine, and salts thereof The ability to preferably use at least one selected from the group consisting of: In addition, when an amino acid has an optical isomer, any of L-form, D-form and racemic form can be suitably used.

[0050] As the aminocarboxylic acid, compounds other than the above amino acids, which have both an amino group and a strong carboxyl group in one molecule, can be widely used. Among these, diethylenetriaminepentaacetic acid (DTP A), hydroxyethylethylenediaminacetic acid (HED TA), triethylenetetraaminehexaacetic acid (TTHA), 1,3-propanediamintetraacetic acid (PDT A), 1,3 —Diamino mono 6-hydroxypropane tetraacetic acid (DPTA—OH), hydroxyethylimino diacetic acid (HIDA), dihydroxyethylglycine (DHEG), glycol ether diamine tetraacetic acid (GEDTA), dicarboxymethyl glutamic acid (CMGA) ), (S 1, S) -ethylenediamine disuccinic acid (EDDS), ethylenediamine 4 acetic acid (EDTA), nitrite 3 acetic acid (NTA) and at least one selected from the group consisting of these salts are preferred Use with power S. [0051] Further, examples of the phenol compound include compounds having two or more phenolic hydroxyl groups and phenol compounds having these as a basic skeleton. Examples of the former include catechol, gallic acid, pyrogallol, tannic acid and the like. On the other hand, examples of the latter include flavonoids such as flavones, isoflavones, flavonols, flavanones, flavanols, anthocyanidins, aurones, force norecons, epigallocatechin gallate, gallocatechin, theaflavin, soybean in, genistin, rutin, myristicin and other flavonoids, tannins, catechins And the like, and polyphenol compounds including polybutanol, water-soluble resols, novolac resins, lignin and the like. Of these, tannin, gallic acid, catechin and pyrogallol are particularly preferred.

 [0052] Examples of the sulfonic acid include metasulfonic acid, isethionic acid, taurine, naphthalene disulfonic acid, amaminonaphthalenedisulfonic acid, sulfosalicylic acid, naphthalenesulfonic acid formaldehyde condensate, alkylnaphthalenesulfonic acid, and the like, and salts thereof. At least one selected from the group consisting of can be preferably used.

 [0053] When sulfonic acid is used, the paintability and corrosion resistance of the object to be treated after the chemical conversion treatment can be improved. The mechanism is not clear, but there are two possible reasons.

 [0054] First, since the surface of an object to be treated such as a steel sheet has silica segregated material and the like and the surface composition is uneven, a force sulfonic acid is added which has a portion which is difficult to be etched in chemical conversion treatment. Thus, it is estimated that such a portion that is difficult to be etched can be etched, and as a result, a uniform metal oxide film is easily formed on the surface of the object to be processed. That is, sulfonic acid is presumed to act as an etching accelerator.

 [0055] The other is that during the chemical conversion treatment, hydrogen gas that may be generated by the chemical conversion reaction may interfere with the interface reaction, and sulfonic acid removes the hydrogen gas as a reversal action and promotes the reaction. And I guess that.

 [0056] Of these, taurine is preferable in that it has both an amino group and a sulfone group. The content of sulphonic acid is preferably from 0.;! To lOOOOppm, more preferably from! To lOOOOppm. If the content is less than 0.1 lppm, it is difficult to obtain the effect. If it exceeds lOOOOppm, precipitation of zirconium may be inhibited.

[0057] When ascorbic acid is used, zirconium oxide is formed on the surface of the workpiece by chemical conversion treatment. Further, a metal oxide film such as tin oxide can be formed uniformly, and paintability and corrosion resistance can be improved. Although its mechanism is not clear, the etching action in the chemical conversion treatment is uniformly performed on the workpiece such as a steel plate, and as a result, zirconium oxide and / or tin oxide is present in the etched portion. It is estimated that a uniform metal oxide film is formed as a whole. In addition, it is presumed that as a result of tin being precipitated as tin metal at the metal interface due to some influence, zirconium oxide is deposited at the deposition site of the tin metal, and the surface coverage on the object to be treated is improved as a whole. The The content of ascorbic acid is preferably 5 to 5000 ppm force S, more preferably 20 to 200 ppm force S. If the content is less than S5ppm, it is difficult to obtain the effect. If it exceeds 5000ppm, the deposition of zirconium may be hindered.

 [0058] When the chelating agent is included, the content thereof is preferably 0.5 to 10 times the total concentration of other cations such as tin ions other than zirconium and copper ions. If it is less than 5 times, the desired effect cannot be obtained, and if it exceeds 10 times, the film formation may be adversely affected.

 [0059] The metal surface treatment liquid for cationic electrodeposition coating of the present invention may further contain nitrogen, sulfur and / or a phenolic antifungal agent. The antifungal agent can suppress corrosion by forming an anticorrosive film on the metal surface. As the nitrogen, sulfur, or phenolic antifungal agent, at least one selected from the group consisting of hydroquinone, ethylene urea, quinolinol, thiourea, benzotriazole, and the like and salts thereof can be used. Power of the present invention When nitrogen, sulfur, or a phenolic antifungal agent is used in the metal surface treatment solution for thione electrodeposition coating, metal oxides such as zirconium oxide and tin oxide are formed on the surface of the object by chemical conversion treatment. A film is formed uniformly, and paintability and corrosion resistance can be improved. The mechanism is not clear, but the following is presumed.

[0060] That is, because the surface of the steel sheet contains silica segregated materials and the surface composition is non-uniform, the etching behavior is different from the portion where the chemical conversion film is etched to form a chemical conversion film. There is a portion where the chemical conversion film is not formed and becomes iron oxide. Nitrogen, sulfur, and phenolic antifungal agents improve the primary antifungal property by covering the metal interface by adsorbing to the part where the chemical conversion film is not formed during chemical conversion treatment, and as a result, after chemical conversion treatment Treatment of It is presumed that the paintability and corrosion resistance of physical products can be improved.

[0061] Further, when copper is excessively deposited in the chemical conversion film, this copper may become a force sword base point and an electrically non-uniform chemical conversion film. By adsorbing the antifungal agent, it is presumed that uniform electrodeposition coatability can be obtained in the workpiece after chemical conversion treatment, and corrosion resistance can be improved.

[0062] The content of nitrogen, sulfur and / or phenolic antifungal agent is preferably 0.1 to 10,000 ppm;! To l OOOppm is more preferable. If the content is less than 0.1 lppm, it is difficult to obtain the effect. L If it exceeds OOOOppm, precipitation of zirconium may be hindered.

 [0063] The metal surface treatment liquid for cationic electrodeposition coating of the present invention may further contain aluminum ions and / or indium ions. Since these cations have the same function as tin ions, they are not effective with tin ions alone, and can be used in combination. Among these, aluminum is more preferable. Contains aluminum ions and / or indicium ions! : (Oh, 10 ~;! OOOppm preferred <, 50-500ppm force preferred <, 100-300ppm force S More preferred. The amount of aluminum ions and indium ions is based on the concentration of zirconium ions. For example, the concentration corresponding to 2 to 1000% is reduced by force S. The metal surface treatment liquid for cationic electrodeposition coating of the present invention is for cationic electrodeposition coating containing zirconium ions, tin ions, and aluminum ions. Examples thereof include metal surface treatment liquids, which can further contain fluorine described later, and can also include a polyamine compound described later.

 [0064] In addition to the above components, the metal surface treatment liquid for cationic electrodeposition coating of the present invention may contain various cations. Examples of the cation include magnesium, zinc, calcium, gallium, iron, manganese, nickel, cobalt, silver and the like. In addition to these, there are cationic anions that are added for the purpose of pH adjustment and are derived from bases and acids, or are included as counters of the above components.

 [0065] The metal surface treatment liquid for cationic electrodeposition coating of the present invention can be produced by putting the above components themselves and / or a compound containing the same into water and mixing them.

[0066] Examples of the compound supplying the zirconium ion include fluorinated zirconate and fluorine. Examples thereof include salts of fluorinated zirconate such as potassium zirconate fluoride and ammonium fluoride zirconate, zirconium fluoride, zirconium oxide, zirconium oxide colloid, zirconyl nitrate, and zirconium carbonate.

 [0067] Examples of compounds that supply tin ions include tin sulfate, tin acetate, tin fluoride, tin chloride, and tin nitrate. On the other hand, examples of the compound that supplies fluoride ions include fluorides such as hydrofluoric acid, ammonium fluoride, boron fluoride, ammonium hydrogen fluoride, sodium fluoride, and sodium hydrogen fluoride. It is also possible to use a complex fluoride as a source, for example, hexafluorosilicate, specifically, key hydrofluoric acid, key zinc hydrofluoride, manganese key hydrofluoride, key hydrofluoric acid. Examples thereof include magnesium, nickel key hydrofluoride, iron key hydrofluoride, and calcium key hydrofluoride. Further, it may be a compound that supplies zirconium ions and is a complex fluoride. Furthermore, copper acetate, copper nitrate, copper sulfate, copper chloride, etc. are used as the compounds that supply copper ions, aluminum nitrate, aluminum fluoride, etc. are used as the compounds that supply aluminum ions, and nitric acid is used as the compound that supplies indium ions. Examples thereof include indium and indium chloride.

 [0068] The metal surface treatment liquid for cationic electrodeposition coating of the present invention, after mixing these, uses an acidic compound such as nitric acid and sulfuric acid, and a basic compound such as sodium hydroxide, potassium hydroxide and ammonia. Thus, it is possible to adjust the power so that a predetermined pH value is obtained.

 [0069] The metal surface treatment liquid for cationic electrodeposition coating of the present invention may contain an oxidizing agent. The oxidizing agent is particularly preferably at least one selected from the group consisting of nitric acid, nitrous acid, hydrogen peroxide, bromic acid and the like and salts thereof. The oxidizing agent can uniformly form a metal oxide film on the surface of the object to be processed, and can improve the paintability and corrosion resistance of the object to be processed.

[0070] Although the mechanism is not clear, by using a predetermined amount of the oxidizing agent, the etching action in the chemical conversion treatment is uniformly performed on the object to be processed such as a steel plate, and the etched portion has zirconium. It is presumed that oxide and / or tin oxide precipitates to form a uniform metal oxide film as a whole. In addition, the predetermined amount of the oxidizer makes it easy for tin to precipitate as tin metal at the metal interface, and the tin metal is deposited at the site of precipitation. It is presumed that zirconium oxide precipitates and the surface coverage on the object to be treated is improved as a whole.

 [0071] In order to exhibit such an action, the content of each oxidizing agent is as follows. That is, the content of isotonic acid is 100-;! OOOOOOppm is preferred <, 1000-20,000 ppm is preferred, 2000-; OOOOppm power S is more preferred. The content of nitrous acid and bromic acid is preferably 5 to 5000 ppm force S, more preferably 20 to 200 ppm force S. The content of nitrous acid and bromic acid is preferably 5 to 5000 ppm force S, more preferably 20 to 200 ppm force S. The content of hydrogen peroxide is 1 ~;! OOppm is preferred 5 ~;! OOppm power is more preferred. If each content is less than the lower limit, the precipitation of zirconium may be hindered if the upper limit is exceeded where the above effects are difficult to obtain.

 [0072] The metal surface treatment method of the present invention includes a step of performing a surface treatment on a metal substrate using the above metal surface treatment liquid.

 [0073] The metal substrate is not particularly limited as long as it can be cationically electrodeposited. Examples thereof include iron-based metal substrates, aluminum-based metal substrates, and zinc-based metal substrates. The power S can be raised.

 [0074] Examples of the iron-based metal base material include cold-rolled steel sheets, hot-rolled steel sheets, mild steel sheets, and high-tensile steel sheets. In addition, examples of the aluminum-based metal base material include a 5000-series aluminum alloy, a 6000-series aluminum alloy, an aluminum-plated steel sheet such as an aluminum-based electroplating, melt-bonding, and vapor-deposition plating. . Examples of zinc-based metal base materials include zinc-based steel plating, zinc-plated steel plate, zinc-nickel-plated steel plate, zinc-titanium-plated steel plate, zinc-magnesium-plated steel plate, and zinc-manganese-plated steel plate. The ability to list zinc or zinc-based alloy-plated steel sheets, etc. There are various grades of high-strength steel sheets depending on the strength and manufacturing method, such as JSC400J, JSC440P, JSC440W, JSC590R, JS C590T, JSC590Y, JSC780T, JSC780Y, JSC980Y, JSCl 180Y Power S can be.

[0075] Further, as the metal substrate, a metal substrate made of a combination of a plurality of types of metals such as iron-based, aluminum-based, and zinc-based (including joints and contact portions of different metals) Can also be applied simultaneously.

[0076] The surface treatment step is performed by bringing the metal surface treatment liquid into contact with the metal substrate. Specific examples of the method include a dipping method, a spray method, a roll coating method, and a pouring treatment method.

[0077] The treatment temperature in the surface treatment step is preferably in the range of 20 to 70 ° C.

. If it is less than 20 ° C, sufficient film formation may not be performed, and if it exceeds 70 ° C, an effect commensurate with it cannot be expected. Further preferred lower and upper limits are 3 respectively.

0 ° C and 50 ° C.

 [0078] The treatment time in the surface treatment step is preferably 2 to 1100 seconds. If it is less than 2 seconds, a sufficient amount of film may not be obtained, and even if it exceeds 1100 seconds, no effect can be expected. Further preferred lower and upper limit values are 30 seconds and 120 seconds, respectively. In this way, a film is formed on the metal substrate.

 [0079] The surface-treated metal substrate of the present invention is obtained by the above surface treatment method. A film containing zirconium and tin is formed on the surface of the metal substrate. The element ratio of zirconium / tin in the coating is preferably 1/10 to 10/1 in terms of mass. Outside this range, the desired performance may not be obtained.

[0080] The content of zirconium in the coating is preferably 10 mg / m ² or more in the case of an iron-based metal substrate. If it is less than 10 mg / m ² , sufficient corrosion resistance cannot be obtained. More preferably, it is 20 mg / m ² or more, and further preferably 30 mg / m ² or more. The upper limit is not particularly defined, but if the amount of the film is too large, cracks are likely to occur in the fender film, making it difficult to obtain a uniform film. In this respect, the zirconium content in the coating is preferably lg / m ² or less, more preferably 800 mg / m ² or less.

[0081] When the film is formed using a metal surface treatment liquid containing copper ions, the copper content in the film is 0.5 mg / m ² or more in order to obtain the desired effect. I prefer that.

[0082] The cationic electrodeposition coating method of the present invention includes a step of performing a surface treatment on a metal substrate using the above-described metal surface treatment liquid, and a cation for the metal substrate subjected to the surface treatment. And a process of performing electrodeposition coating. [0083] The surface treatment step in the cationic electrodeposition coating method is the same as the surface treatment step in the previous surface treatment method. The surface-treated metal substrate obtained in the surface treatment step enters the cationic electrodeposition coating step as it is or after washing.

 [0084] In the cationic electrodeposition coating step, cathodic electrodeposition coating is performed on the metal base material that has been surface-treated. In the cationic electrodeposition coating, a metal substrate subjected to the above surface treatment is immersed in a cationic electrodeposition coating, and a voltage of 50 to 450 V is applied for a predetermined time using this as a cathode. The voltage application time varies depending on the electrodeposition conditions and is generally 2 to 4 minutes.

 [0085] As the cationic electrodeposition coating, generally well-known ones can be used. Specifically, a binder cationized by adding an amine sulfide to an epoxy group of an epoxy resin or an acrylic resin and adding a neutralizing acid such as acetic acid, a block isocyanate as a curing agent, and an anti-blocking agent. In general, a pigment dispersion paste in which a pigment having inertia is dispersed with a resin is added to form a paint.

[0086] After completion of the cationic electrodeposition coating process, the cured coating film is obtained by baking at a predetermined temperature as it is or after washing with water. Baking conditions vary depending on the type of cationic electrodeposition paint used, usually 120 to 260 ° C, preferably 140 to 220 ° C. The baking time can be 10-30 minutes.

 The metal substrate coated with cationic electrodeposition obtained in this way is also one aspect of the present invention. Example

 [0087] Production Example 1 Production of Hydrolyzed Condensate of Aminosilane Part 1

 As aminosilane, KBE603 (3-aminopropyl monotriethoxysilane, effective concentration 100%, manufactured by Shin-Etsu Chemical Co., Ltd.), 5 parts by mass from a dropping funnel, 47.5 parts by mass of deionized water and 47.5 parts by mass of isopropyl alcohol After dropwise addition over 60 minutes uniformly in a mixed solvent (solvent temperature: 25 ° C), the reaction was carried out at 25 ° C for 24 hours under a nitrogen atmosphere. Thereafter, the reaction solution was depressurized to evaporate isopropyl alcohol and further deionized water to obtain a hydrolyzed condensate of aminosilane having an active ingredient of 5%.

 [0088] Revelation 2 The power of aminosilane Revelation 2

In Production Example 1, the amount of KBE603 was changed to 20 parts by mass, the amount of deionized water was changed to 40 parts by mass, and the amount of isopropyl alcohol was changed to 40 parts by mass. A hydrolysis condensate of 20% aminosilane was obtained.

[0089] Example 1

 After mixing 40% dinoleconic acid aqueous solution as a zirconium ion source, tin sulfate as a tin ion source, and hydrofluoric acid, this was diluted to a zirconium ion concentration of 500 ppm and a tin ion concentration of 30 ppm. In addition, the pH was adjusted to 3.5 using nitric acid and sodium hydroxide to obtain a metal surface treatment solution for cationic electrodeposition coating. After preparing this treatment solution at ρΗ3.0, the free fluorine ion concentration when measured with a fluorine ion meter was 5 ppm.

[0090] Example 2

 In Example 1, the aminosilane hydrolysis condensate obtained in Production Example 1 was added to 200 ppm, and tin sulfate was changed to tin acetate to change the tin ion concentration to lO ppm. A metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner except that the pH was 2.75. After adjusting this treatment solution to pH 3.0, the free fluorine ion concentration when measured using a fluorine ion meter was 5 ppm.

 [0091]

 In Example 1, “polyallylamine ^ —H-10C” (trade name, manufactured by Nitto Boseki Co., Ltd.) was added to 25 ppm, the zirconium ion concentration was changed to 250 ppm, and the pH was adjusted to 3 A metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner except that the value was 0. In addition, this treatment solution had a free fluorine ion concentration of 5 ppm when measured using a fluorine ion meter.

[0092] Example 4

 In Example 1, copper nitrate was further added so that the copper ion concentration became lOppm, the tin ion concentration was changed to lOppm, and the pH was changed to 3.0 in the same manner. A metal surface treatment solution for electrodeposition coating was obtained. For this treatment solution, the free fluorine ion concentration when measured using a fluorine ion meter was 5 ppm.

[0093] Example 5

In Example 4, the aminosilane hydrolyzed condensate obtained in Production Example 2 was added to 200 ppm, and the tin ion concentration was changed to 30 ppm. In this manner, a metal surface treatment solution for cationic electrodeposition coating was obtained. This treatment solution had a free fluorine ion concentration of 5 ppm when measured using a fluorine ion meter.

 [0094] Example 6

 In the same manner as in Example 2, except that aluminum nitrate was further added to have an aluminum ion concentration of 200 ppm, and tin sulfate was changed to tin acetate to change the tin ion concentration to 30 ppm. A metal surface treatment solution for electrodeposition coating was obtained. After adjusting this treatment solution to pH 3.0, the free fluorine ion concentration when measured using a fluorine ion meter was 5 ppm.

 [0095] Examples 7 and 8

 A metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner as in Example 6, except that the pH was 3.5 and 4.0. Table 1 shows the free fluorine ion concentration when this treatment solution was adjusted to pH 3.0 and then measured using a fluorine ion meter.

 [0096] Examples 9 to 16

 In Example 7, except that the addition amount of 40% aqueous zirconate solution, tin sulfate, and aluminum nitrate was changed so that the zirconium ion concentration, tin ion concentration, and aluminum ion concentration were as shown in Table 1. Similarly, a metal surface treatment solution for cationic electrodeposition coating was obtained. Table 1 shows the free fluorine ion concentration when this treatment solution was adjusted to pH 3.0 and then measured using a fluorine ion meter.

 [0097] Example 17

 In Example 2, indium nitrate was further added so that the indium ion concentration became 200 ppm, and tin sulfate was changed to tin fluoride so that the tin ion concentration became 30 ppm. Further, the pH was changed to 3.5. A metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner as described above. After adjusting this treatment solution to ρΗ3.0, the free fluorine ion concentration when measured using a fluorine ion meter was 5 ppm.

[0098] Example 18

In Example 2, diethylenetriaminepentaacetic acid (DTPA) was further added as a chelating agent to a concentration of lOOppm, and tin acetate was changed to tin sulfate so that the tin ion concentration was 30pp. The metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner except that the zirconium ion concentration was changed to lOOOppm. After adjusting the treatment solution to pH 3.0, the free fluorine concentration when measured using a fluorine ion meter was 1 Oppm.

[0099] Example 19

 In the same manner as in Example 2, except that sodium nitrate was further added so that the sodium ion concentration was 5000 ppm, and the tin ion concentration was changed to 30 ppm, the metal surface treatment liquid for force thione electrodeposition coating was used. Got. After adjusting this treatment solution to pH 3.0, the free fluorine ion concentration when measured using a fluorine ion meter was 5 ppm.

 [0100] Example 20

 In Example 5, glycine and copper nitrate as chelating agents were further added so that the concentration of 50 ppm and the copper ion was 10 ppm, respectively, and the polyamine concentration was changed to ΙΟΟρρ m in the same manner. Thus, a metal surface treatment solution for cationic electrodeposition coating was obtained. This treatment solution had a free fluorine ion concentration of 5 ppm when measured using a fluorine ion meter.

[0101] Examples 21-31

 In Example 1, a metal surface treatment solution for cationic electrodeposition coating was prepared in the same manner except that a predetermined amount of the polyamine listed in Table 1 was added and the concentrations of other components were changed as described in Table 1. I got each. Table 1 also shows the free fluorine ion concentrations when these treatment solutions were measured using a fluorine ion meter under the condition of ρΗ3.0.

[0102] Examples 32-50

A metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner as in Example 1 except that a predetermined amount of the sulfonic acid described in Table 2 was added and the polyamine and other components were changed as shown in Table 2. For these treatment solutions, the free fluorine ion concentrations measured using a fluorine ion meter under the condition of ρΗ3.0 are also shown in Table 2. In Table 2, naphthalene sulfonic acid formaldehyde condensates are Kao's demoles. For NL and sodium alkylnaphthalene sulfonate, Kao Perex NBL was used, and for sodium polystyrene sulfonate, Tosoh P-NASS-1 was used.

[0103] Example 51

 A metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner as in Example 1 except that a predetermined amount of ascorbic acid described in Table 3 was added and polyamine and other components were changed as shown in Table 3. Table 3 also shows the free fluorine ion concentrations when these treatment solutions were measured using a fluorine ion meter under a pH of 3.0.

 [0104] Examples 52-59

 A metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner as in Example 1 except that a predetermined amount of the oxidizing agent shown in Table 3 was added and that the polyamine and other components were changed as shown in Table 3. Table 3 also shows the free fluorine ion concentrations when these treatment solutions were measured using a fluorine ion meter under the condition of ρΗ3.0.

 [0105] Examples 60-74

 In Example 1, except that the nitrogen-based antifungal agent, sulfur-based antifungal agent, and phenolic antifungal agent described in Table 3 were added in predetermined amounts, and the polyamine and other components were as shown in Table 3. In the same manner as in Example 1, metal surface treatment solutions for cationic electrodeposition coating were obtained. Table 3 also shows the free fluorine ion concentrations when these treatment solutions were measured using a fluorine ion meter under the condition of ρΗ3.0.

 [0106] Examples 75 to 77

 Except that the substrate to be processed was a high-tensile steel plate instead of a cold-rolled steel plate (SPC) and the polyamines and other components listed in Table 3 were as shown in Table 3, the same as in Example 1, Strength Each metal surface treatment solution for thione electrodeposition coating was obtained. Table 3 also shows the free fluorine ion concentrations of these treatment solutions when measured with a fluorine ion meter under the condition of ρΗ3.0.

 [0107] Examples 78 to 106

For Examples 2, 3, and 5 to 31, a metal surface treatment solution for cationic electrodeposition coating was obtained in the same manner as in each Example except that polyamine was not added. In addition, after adjusting this treatment solution to ρ フ リ ー 3.0, free fluorine ions when measured using a fluorine ion meter The concentration is shown in Table 4.

[0108] Comparative Example:! ~ 6 Preparation of Comparative Metal Surface Treatment Solution

 Based on the descriptions in Tables 1 and 3, comparative metal surface treatment solutions were obtained based on the above examples. The obtained metal surface treatment liquids are summarized in Tables 1 and 3.

[0109] [Table 1]

[0110] [Table 2]

[0111] [Table 3]

[0112] [Table 4] Degree Tin ion supply Sn; Degree Additive component (concentration (ppm) in ΐΐ ツ コ)

 Sn pH Free-Fluorine (ppm) Compound (ppm) Oriamine Compound Other Ion Concentration Implementation '| 78 500 Tin sulfate 10 0.02 2.75 5 Implementation ί? | J79 250 Tin sulfate 30 0.12 3 5 Implementation <? L | 80 500 Tin sulfate 30 0.06 3 Copper nitrate (10) 5 Implementation 81 500 Tin sulfate 30 0.06 2.75 Aluminum nitrate (200) 5 Implementation 'fi | 82 500 Tin acetate 30 0.06 3.5 Aluminum nitrate (200) 5 Implementation 3 500 Tin acetate 30 0.06 4 Nitric acid Aluminum (200) 5 Implementation f? | J84 1000 Tin acetate 30 0.03 3.5 Aluminum nitrate (200) 7 Implementation | 85 500 Tin acetate 30 0.06 3.5 Aluminum nitrate (500) 5 Implementation 1 86 500 Tin acetate 30 0.06 3.5 Aluminum nitrate (1000 5 Implementation 500 Tin acetate 10 0.02 3.5 Aluminum nitrate (500) 5 Implementation 88 500 Tin acetate 200 0.4 3.5 1 Aluminum nitrate (500) 5

? 1 89 200 Tin acetate 10 0.05 3.5 One aluminum nitrate (200) 7 Implementation '90 200 Tin acetate 30 0.15 3.5 Aluminum nitrate (200) 5 Implementation? 1 91 200 Tin acetate 70 0.35 3.5 Aluminum nitrate (200) 5 Implementation ? 1 92 500 Tin fluoride 30 0.06 3.5 Nitrate In (50) 5 Implementation '?! 93 1000 Tin sulfate 30 0.03 2.75 DTPA (100) 10 Implementation' 500 Tin sulfate 30 0.06 2.75 Sodium mononitrate (5000) 5 Implementation? l 95 500 Tin sulfate 30 0.06 3 1 Copper nitrate (10), Gericin (50) 5 Implementation 96 20 Tin sulfate 5 0.25 3 1 2 Implementation f 500 Tin sulfate 20 0.04 2 1 1 Example 98 500 Tin sulfate 30 0.06 5.5 20 Implementation i? Lj99 5000 Tin sulfate 25 0.005 3 10 Implementation 100 50 Tin sulfate 10 0.2 3 3 Implementation 101 50 Tin sulfate 50 1 3 1 Implementation '102 500 Tin sulfate 30 0.06 3 0 Implementation' 3 500 Tin sulfate 30 0.06 2.75 1 0.1 Implementation 104 500 Tin sulfate 30 0.06 2.75 1 0.6 Implementation? 1] 105 500 Tin sulfate 30 0.06 4 1 20 Implementation i? Lj 106 500 Tin sulfate 30 0.06 4.5 50

 [0113] <Surface treatment>

 Examples;! To 74, Examples 78 to; 106, Comparative Examples;! To 5 are commercially available cold-rolled steel sheets (SPC, 70 mm XI 50 mm X O. 8 mm) manufactured by Nippon Test Panel Co., Ltd. In Examples 75 to 77 and Comparative Example 6, a high-tensile steel plate (70 mm x 150 mm x l. Omm) was prepared. In contrast, “surf cleaner EC92” (trade name, Nippon Paint) was used as an alkaline degreasing agent. Was used for degreasing treatment at 40 ° C for 2 minutes. This was immersed and washed in a water washing tank and then spray washed with tap water for about 30 seconds.

 [0114] Surface treatment was performed by immersing the metal substrate after degreasing treatment in metal surface treatment solutions prepared in Examples and Comparative Examples for 90 seconds at 40 ° C. However, for Examples 21 and 22, the treatment times were 240 seconds and 15 seconds, respectively. After completion of the surface treatment, drying was performed at 40 ° C. for 5 minutes or more to obtain a surface-treated metal substrate. Unless otherwise specified, this surface-treated metal substrate was used as a test plate in the following evaluation.

 [0115] <Measurement of element content in film>

The content of each element contained in the film was measured using a fluorescent X-ray analyzer “XRF 1700” manufactured by Shimadzu Corporation. [0116] <Primary defense>

 [0117] The state of wrinkles after the test plate was immersed in pure water at 25 ° C for 5 hours was observed by visual observation.

Yes

 ○: No occurrence of soot

 Δ: Slightly wrinkled

 X: The occurrence of wrinkles can be clearly seen

[0118] <Observation of sludge>

 With respect to 10 L of the surface treatment liquid of the examples and comparative examples, 200 test panels were surface-treated, and it was visually confirmed whether or not turbidity due to sludge occurred in the surface treatment liquid after 30 days at room temperature. The evaluation was based on the following criteria.

 ◎: Transparent liquid

 ○: Slightly cloudy

 Δ: Cloudy

 X: Precipitate (sludge) generated

[0119] <Evaluation of throwing power>

 The throwing power was evaluated by the “four-sheet box method” described in Japanese Patent Application Laid-Open No. 2000-038525. That is, as shown in Fig. 1, box 10 was adjusted in which test plates 1 to 4 were erected, placed in parallel at an interval of 20 mm, and sealed at the bottom and bottom of both sides with an insulator such as cloth adhesive tape. . Metal materials 1, 2, and 3 except metal material 4 were provided with through holes 5 having a diameter of 8 mm at the bottom.

 [0120] The box 10 was immersed in an electrodeposition coating container 20 filled with a cationic electrodeposition paint "Power Nitas 110" (trade name, manufactured by Nippon Paint Co., Ltd.). In this case, the cationic electrodeposition paint enters the inside of the box 10 only from each through hole 5.

[0121] While stirring the cationic electrodeposition paint with a magnetic stirrer, each test plate;! To 4 was electrically connected, and the counter electrode 21 was arranged so that the distance from the test plate 1 was 150 mm. Cationic electrodeposition coating was performed by applying a voltage with each test plate 1 to 4 as a cathode and the counter electrode 21 as an anode. The coating was performed by increasing the voltage to the target voltage (210V and 160V) over 30 seconds from the start of application, and then maintaining that voltage for 150 seconds. Adjust the bath temperature to 30 ° C. did.

 [0122] After coating, each test plate 1 to 4 was washed with water, baked at 170 ° C for 25 minutes, then air-cooled, and the coating film formed on side A of test plate 1 closest to counter electrode 21 And the film thickness of the coating film formed on the G surface of the test plate 4 both far from the counter electrode 21 and the ratio of the film thickness (G surface) / film thickness (A surface) By seeking, throwing power was evaluated. The larger this value, the better the messiness! /. The passing level is over 40%.

[0123] <Paint voltage>

 Using the surface treatment liquids of Examples and Comparative Examples, surface treatment was performed on cold-rolled steel sheets and galvanized steel sheets to obtain test plates. For these test plates, the voltage required to obtain a 20 m electrodeposition coating film was obtained using the above-mentioned cationic electrodeposition coating material “Power Nitas 110”. The difference in the coating voltage required to obtain the electrodeposition coating film of 2 (^ 111) was determined when the metal substrate was a zinc-plated steel sheet and a cold-rolled steel sheet. Shows that it is excellent as a physical coating! /, 40 / V is acceptable.

[0124] The voltage required to obtain an electrodeposition coating film of 20 m was determined as follows. In other words, as the electrodeposition conditions, the voltage is increased to a predetermined voltage in 30 seconds and then held for 150 seconds, and the resulting film thickness is measured. This is performed for 150V, 200V, and 250V, and the voltage at which a film thickness of 20 am is obtained is obtained from the relational expression between the obtained voltage and the film thickness.

[0125] <Paint appearance>

 The test plate was subjected to cationic electrodeposition coating, and the appearance of the obtained electrodeposition coating film was evaluated according to the following criteria. The results are shown in Tables 5-8.

 A: A uniform coating film is obtained.

 ○: An almost uniform coating film is obtained!

 Δ: Some unevenness in the coating film

 X: Unevenness is observed in the coating film

[0126] <Secondary adhesion test (SDT)>

After forming a 20 m electrodeposition coating on the test plate, two longitudinally parallel cuts reaching the metal substrate were put and immersed in a 5% aqueous sodium chloride solution at 55 ° C for 240 hours. Next, after washing and air drying, the adhesive tape “ELPACK LP-24” (trade name, Nichiban Co., Ltd.) was adhered, and then the adhesive tape was peeled off rapidly. The maximum width (one side) of the paint adhering to the peeled adhesive tape was measured.

 (O): Omm

 ○: Less than 2mm

 Δ: 2mm or more, less than 5mm

 X: 5mm or more

[0127] <Cycle corrosion test (CCT)>

 After forming a 20 m electrodeposition coating on the test plate, the edges and back were tape sealed, and a cross-cut punch reaching the metal substrate was inserted. This was continuously sprayed with a 5% sodium chloride aqueous solution maintained at 35 ° C for 2 hours in a salt spray tester maintained at 35 ° C and 95% humidity. Next, it was dried for 4 hours under the conditions of 60 ° C and humidity of 20-30%. This was repeated three times during 24 hours to make one cycle, and after 200 cycles, the swollen width (both sides) of the coating film was measured.

 : Less than 6mm

 ○: 6mm or more and less than 8mm

 Δ: 8 mm or more and less than 10 mm

 X: 10mm or more

[0128] <Salt spray test (SST)>

 After forming a 20 m electrodeposition coating on the test plate, the edges and back were tape sealed, and a cross-cut punch reaching the metal substrate was inserted. This was continuously sprayed with a 5% sodium chloride aqueous solution maintained at 35 ° C for 840 hours in a salt spray tester maintained at 35 ° C and 95% humidity. Next, after washing with water and air drying, the adhesive tape “ELVAC LP-24” (trade name, manufactured by Nichiban Co., Ltd.) was adhered to the cut part, and then the adhesive tape was peeled off rapidly. The maximum width (one side) of the paint adhering to the peeled adhesive tape was measured.

○: Less than 2mm

 Δ: 2mm or more, less than 5mm

 X: 5mm or more

[0129] The evaluation results are summarized in Tables 5-8. [0130] [Table 5]

[0131] [Table 6]

[0132] [Table 7] Moto * sha * M Primary slang Throw resistance [%] m SDT CCT SST

Zr Si Sn Cu Protection observation 21 OV 1 60V difference (V) Appearance Example 51 91 5.7 19 ○ ○ 62 55 30 ○ Example 52 75 5.1 21 ○ ○ 57 50 30 ○ Example 53 81 5.3 18 ○ ○ 56 51 30 ◎ ○ Example 54 88 5.7 14 ○ ○ 59 47 30 ◎ ○ Example 55 72 4.8 17 ○ ○ 60 50 30 ◎ ○ Example 56 72 18 6 ○ ○ 59 51 20 ◎ ○ ○ ○ ○ Example 57 85 21 ○ ○ 57 48 30 ○ ○ ○ Example 58 91 20 7 ○ ○ 59 51 20 ○ ○ ○ Example 59 94 18 ○ ○ 60 52 30 ○ ○ ○ Example 60 44 3.2 15 ○ ○ 62 55 30 ○ Example 61 46 3.1 19 ○ ○ 61 51 30 ◎ ◎ ○ Example 62 49 3.6 18 ○ ○ 60 53 30 ◎ o Example 63 38 3 20 ○ ○ 65 57 20 ◎ ○ Example 64 44 3.2 16 ○ ○ 66 55 20 ◎ o Example 65 41 3.5 17 ○ ○ 61 58 20 ◎ ○ Example 66 49 3.2 16 ○ ○ 62 55 30 ◎ ○ Example 67 41 3.2 15 7 ○ ○ 68 59 20 ◎ ○ Example 68 51 18 7 ○ ○ 59 53 30 ○ ○ Example 69 52 18 5 ○ ○ 63 51 30 ○ ○ Example 70 48 19 9 ○ ○ 61 53 30 ◎ ○ Example 71 55 17 6 ○ ○ 65 55 30 ○ ○ Example 72 43 16 10 ○ ○ 62 58 20 ○ ○ Example 73 49 20 7 ○ ○ 66 54 20 ○ o Example 74 52 17 5 ○ ○ 62 52 30 ○ ◎ ○ Example 75 67 4.7 18 ○ ○ 59 52 30 ◎ ◎ o Example 76 54 3.2 16 ○ ○ 62 58 20 ◎ ○ Example 77 48 2.8 17 o 59 50 30 o Comparative Example 6 58 4.2 Δ ○ 22 10 80 Δ ○ △

[0133] [Table 8]

 Industrial applicability

 [0134] The metal surface treatment liquid for cationic electrodeposition coating of the present invention can be applied to a metal substrate to be subjected to cationic electrodeposition, such as an automobile body or a part.

Claims

 The scope of the claims  [I] A metal surface treatment solution for cationic electrodeposition coating containing zirconium ions and tin ions and having a pH of 1 · 5 to 6.5,  The concentration of the dinoleconium ion is 10 to 10,000 ppm, and  The concentration ratio of tin ions to zirconium ions is 0.005 to;! In terms of mass.  Metal surface treatment solution for cationic electrodeposition coating. [2] The metal surface treatment liquid for cationic electrodeposition coating according to claim 1, further comprising a polyamine compound.  [3] The metal surface treatment solution for cationic electrodeposition coating according to claim 1 or 2, further comprising copper ions.  [4] The metal surface for cationic electrodeposition coating according to any one of Claims 1 to 3, further comprising fluorine ions, wherein the amount of free fluorine ions when the pH is 3.0 is 0.1 to 50 ppm. Treatment liquid.  [5] The metal surface treatment solution for cationic electrodeposition coating according to any one of claims 1 to 4, further comprising a chelate compound.  6. The metal surface treatment solution for cationic electrodeposition coating according to claim 5, wherein the chelate compound is sulfonic acid.  [7] The metal surface treatment solution for cationic electrodeposition coating according to any one of [6] to [6], further comprising an oxidizing agent.  [8] The metal surface treatment solution for cationic electrodeposition coating according to any one of [8] to [7], further comprising aluminum ions and / or indium ions. [9] A metal surface treatment method comprising a step of performing a surface treatment on a metal substrate using the metal surface treatment liquid according to any one of claims 1 to 8. [10] A metal substrate obtained by the method according to claim 9, and having a film formed by surface treatment.  11. The metal substrate according to claim 10, wherein an element ratio of zirconium / tin in the film is 1/10 to 10/1 in terms of mass. [12] Using the metal surface treatment liquid according to any one of claims 1 to 8, the surface of the metal substrate A cationic electrodeposition coating method, comprising: a step of performing a treatment; and a step of performing cationic electrodeposition coating on the metal substrate on which the surface treatment has been performed.  13. A metal substrate coated with cationic electrodeposition, obtained by the method according to claim 12.