JP5462561B2 - Metal surface treatment composition, metal surface treatment method using the same, and metal surface treatment film using the same - Google Patents

Description

  The present invention relates to a metal surface treatment composition capable of forming a film capable of imparting excellent corrosion resistance and coating appearance to a metal material, particularly a metal structure having a complicated shape, and a metal surface treatment using the same. The present invention relates to a method and a metal surface treatment film using them.

  Conventionally, electrodeposition coating having high throwing power has been generally used as a method for imparting excellent corrosion resistance to various metal materials, particularly metal structures having complicated shapes. However, in many cases, the desired corrosion resistance cannot be obtained only with the electrodeposition coating film obtained by electrodeposition coating. Processing was applied.

  Electrodeposition coating consists of an anionic electrodeposition coating in which a coating is deposited by anodic electrolysis in an aqueous paint containing an anionic resin emulsion, and an aqueous coating containing a cationic resin emulsion. Cathodic electrolysis can be broadly divided into cationic electrodeposition coating in which a coating film is deposited. To improve the corrosion resistance of ferrous metal materials, cationic electrolysis, which does not cause the base metal to elute into the paint during electrolytic treatment, is possible. Electrodeposition coating is advantageous, and cationic electrodeposition coating is widely applied to automobile bodies, automobile parts, home appliances, building materials, etc., which are metal components mainly composed of iron-based materials.

  Cationic electrodeposition coating has a long history in the market, and once it was rust-proof by blending chromium and lead compounds. However, since this also has insufficient rust prevention properties, a ground treatment such as a zinc phosphate chemical conversion treatment was essential. Currently, chromium and lead compounds have become virtually unusable due to environmental regulations, especially the European ELV regulations, so alternative components have been studied and their effects have been found in bismuth compounds. Is disclosed.

  Patent Document 1 (Japanese Patent Laid-Open No. 5-32919) discloses a resin composition for an electrodeposition coating, which contains at least one pigment coated with a bismuth compound.

  Patent Document 2 (WO 99/31187) discloses a cationic electrodeposition coating composition comprising an aqueous dispersion paste containing an aqueous dispersion in which an organic acid-modified bismuth compound is present in a water-insoluble form. ing.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-137367) discloses a cationic electrodeposition coating material comprising a colloidal bismuth metal and a resin composition having a sulfonium group and a propargyl group.

  Patent Document 4 (Japanese Patent Application Laid-Open No. 2007-197688) discloses an electrodeposition coating comprising particles of at least one metal compound selected from bismuth hydroxide, a zirconium compound, and a tungsten compound, wherein the metal compound contains 1 to An electrodeposition paint characterized by being 1000 nm is disclosed.

  Patent Document 5 (Japanese Patent Application Laid-Open No. 11-80621) discloses a cationic electrodeposition coating composition containing an aqueous solution of an aliphatic alkoxycarboxylic acid bismuth salt.

  Patent Document 6 (Japanese Patent Laid-Open No. 11-80622) includes an aqueous solution of a bismuth salt with two or more organic acids, wherein at least one of the organic acids is an aliphatic hydroxycarboxylic acid. A cationic electrodeposition coating composition characterized by the above is disclosed.

  Patent Document 7 (Japanese Patent Laid-Open No. 11-100533) discloses a cationic electrodeposition coating composition characterized by containing bismuth lactate using lactic acid containing 80% or more of L isomers among optical isomers. Has been.

  Patent Document 8 (Japanese Patent Laid-Open No. 11-106687) includes an aqueous solution of a bismuth salt containing two or more organic acids, wherein at least one of the organic acids is an aliphatic alkoxycarboxylic acid. A cationic electrodeposition coating composition characterized by the above is disclosed.

  These patent documents can be roughly classified into patent documents 1 to 4 and patent documents 5 to 8. That is, Patent Documents 1 to 4 are those in which a bismuth compound or metal bismuth that is insoluble in an aqueous paint is dispersed, and Patent Documents 5 to 8 dissolve at least the bismuth compound until there is no remaining solids, that is, Bi. It is characterized by being added to the paint after being in an ionic state.

  However, the bismuth compounds in these patent documents only act as substitutes for chromium compounds and lead compounds, and sufficient corrosion resistance cannot be obtained without ground treatment such as zinc phosphate chemical conversion treatment. In fact, these patent documents disclose only examples based on the combination with zinc phosphate chemical conversion treatment.

  On the other hand, recently, a technique has been studied in which corrosion resistance is further improved by a method other than a bismuth compound, and sufficient corrosion resistance can be ensured with one coat without applying a ground treatment such as a zinc phosphate chemical conversion treatment.

For example, Patent Document 9 (Japanese Patent Application Laid-Open No. 2008-274392) discloses a method of forming a film by coating a metal substrate with a film forming agent by at least two stages of multi-stage energization methods, and (i) a film forming agent. Is at least one selected from a zirconium compound and, optionally, titanium, cobalt, vanadium, tungsten, molybdenum, copper, zinc, indium, aluminum, bismuth, yttrium, lanthanoid metal, alkali metal and alkaline earth metal The compound containing metal (a) comprises 30 to 20,000 ppm in terms of total metal (in terms of mass) and 1 to 40% by mass of the resin component, and (ii) the first stage using the metal substrate as the cathode performed by energizing the painting the 1~50V voltage _{(V 1)} 10 to 360 sec 2, then, the metallic substrate as a cathode Wherein the difference in voltage 50~400V eyes after painting done by energizing 60 to 600 seconds _{(V 2),} and (iii) a voltage _{(V 2)} and the voltage _{(V 1)} is at least 10V A method for forming a surface-treated film is disclosed.

  Patent Document 10 (Japanese Patent Application Laid-Open No. 2008-538383) discloses an aqueous coating composition containing (A) a rare earth metal compound, (B) a base resin having a cationic group, and (C) a curing agent, The amount of the rare earth metal compound (A) contained in the coating composition is immersed in an aqueous coating composition in which the amount of the rare earth metal compound is 0.05 to 10% by weight in terms of the rare earth metal with respect to the solid content of the coating. In the dipping process, in the aqueous coating composition, a voltage of less than 50 V is applied using the article to be coated as a cathode, and in the aqueous coating composition, in the aqueous coating composition, the coating article is used as a cathode in the range of 50 to 450 V. A method for forming a multilayer coating film including an electrodeposition coating step of applying a voltage is disclosed.

Japanese Patent Laid-Open No. 5-32919 WO99 / 31187 JP 2004-137367 A JP 2007-197688 A Japanese Patent Laid-Open No. 11-80621 Japanese Patent Laid-Open No. 11-80622 Japanese Patent Laid-Open No. 11-100533 JP-A-11-106687 JP 2008-274392 A JP 2008-538383 A

  As a result of various studies on these prior arts, the present inventors have applied Bi in order to form a coating on a metal material that also provides sufficient corrosion resistance without pretreatment such as a zinc phosphate-based chemical conversion coating. The conclusion is reached that is most effective. And we decided to reconsider the effect of Bi.

  And, as a function and effect of Bi, the function of a resin as a curing catalyst and the anticorrosive action of a base metal have been attracting attention in the past, but the function as a curing catalyst can be expected in the prior art, but the anticorrosive action of a metal. Was considered to be a solution to the problem by maximizing this effect.

  The anticorrosive action of the base metal must be on the surface where Bi contacts with the metal, that is, the interface between the base metal surface and the coating, but in the prior art, the Bi component is uniformly dispersed in the coating and exhibits corrosion resistance. It was estimated that sufficient Bi was not present on the base metal surface.

  As described above, Patent Documents 1 to 4 are those in which a bismuth compound or metal bismuth that is insoluble in an aqueous paint is dispersed. When a film is deposited from such a composition, the film is the same as other pigments. Bi is uniformly dispersed therein.

  Patent Documents 5 to 8 are characterized in that at least the bismuth compound is dissolved until there is no remaining solids, that is, Bi ions are added to the coating material, but the organic acid chelate is a Bi stabilizer. Since the ability is weak, Bi is gradually hydrolyzed when it is put into the composition, and changes to oxide or hydroxide, so long-term stabilization as Bi ion cannot be expected. . As a result, Bi is uniformly dispersed in the film. In these patent documents, the fact that the zinc phosphate-based chemical conversion treatment was used as the base treatment also supports the above-mentioned assumption.

  On the other hand, Patent Document 9 and Patent Document 10 are techniques for depositing an inorganic film on a base metal and laminating a resin film, which is advantageous in terms of anticorrosion of the base metal. Both the resin film and the resin film have a mechanism that precipitates due to the pH increase on the surface of the base metal by cathodic electrolysis, so that it is not easy to form a laminated film.

  In order to solve the above-described problems of the prior art, the present inventors applied an aminopolycarboxylic acid having a high chelating ability in order to make Bi ions exist more stably in the composition, and thus applied to low voltage cathode electrolysis. Thus, a reaction mechanism was found in which resin was deposited by such pH increase at the stage where Bi was diffused and reduced by high voltage cathode electrolysis.

  And it confirmed that the film | membrane obtained by this could fully improve the corrosion resistance of a base metal by Bi which exists in high density | concentration by the base metal surface as well as the hardening catalyst ability of resin which Bi has.

  Furthermore, the present inventors examined increasing the Bi concentration in order to further increase the rust prevention effect. At this time, in order to increase the Bi concentration, the aminopolycarboxylic acid concentration that is a chelating agent may be increased, but in this case, if excessive aminopolycarboxylic acid is incorporated into the coating film, the coating film appearance (specifically, This causes another problem that the glossiness is lowered. The present invention that can solve the above problems is the following (1) to (10).

The present invention (1) contains 5 to 30% by weight of an aqueous resin, 100 to 5000 ppm of trivalent Bi ions, and 0.1 to 5 times the molar concentration of aminopolycarboxylic acid with respect to Bi ions,
At least a part of the water-based resin is represented by the following formula (1):
{Wherein R1 and R2 are independently of each other-(R) m-X (where R is an alkylene group having 1 to 6 carbon atoms, m is 1 or 0, and X is A metal surface treatment characterized by being a nonionic and / or cationic resin having a nitrogen-containing group capable of forming a chelate with Bi ions in the polymer skeleton, represented by hydrogen, carboxyl, hydroxyl or acyl} Composition (metal surface treatment composition for depositing an organic-inorganic composite film by electrolysis).

  In the present invention (2), in the formula (1), R1 and R2 are independently of each other hydrogen, alkyl, hydroxyalkyl, carboxyalkyl (-R-COOH: R is an alkyl group) or alkylcarbonyl (-CO -R: R is an alkyl group), wherein the alkyl part of alkyl, hydroxyalkyl, carboxyalkyl, and alkylcarbonyl is a linear, branched or cyclic group having 1 to 6 carbon atoms. 1) The metal surface treatment composition.

  The present invention (3) is the metal surface treatment composition according to the invention (1) or (2), wherein the aqueous resin is a modified epoxy resin.

  In the present invention (4), the modified epoxy resin is bisphenol A type, and the nitrogen-containing group is directly bonded to the benzene ring portion of the phenylene group instead of the glycidyl ether portion in the modified epoxy resin. The metal surface treatment composition according to (3).

  In the present invention (5), the bisphenol A-type modified epoxy resin (A) comprises, as raw materials, a modified resin (B), an epoxy resin (C) having an epoxy equivalent of 180 to 2500, and a phenol compound having the nitrogen-containing group (D Or a secondary amino group-containing compound (F) and / or bisphenol A (E), and an aminated product of a modified epoxy resin obtained by reacting them. It is a composition for metal surface treatment.

In the present invention (6), the compound (D) is represented by the following formula (2):
(Formula 4)
(Wherein R3 is the nitrogen-containing group or hydrogen atom, at least one of R3 is the nitrogen-containing group; R4 is independently hydrogen or an alkyl group having 1 to 2 carbon atoms. The composition for metal surface treatment of the said invention (5) which is an amine addition phenol compound shown by this.

  This invention (7) is metal surface treatment any one of said invention (1)-(6) whose molar concentration of the said nitrogen-containing group is 0.1-200 times with respect to trivalent Bi ion. Composition.

  The present invention (8) includes a step of depositing a coating film on the surface of a metal material in an electrolytic treatment process using the composition according to any one of the inventions (1) to (7) as a cathode. This is a surface treatment method.

The present invention (9) is a metal surface for depositing a film on a metal material, comprising an electrolysis process for subjecting the metal material having a cleaned surface to an electrolysis process, and a water washing and baking process performed after the electrolysis process. In the processing method,
The electrolytic treatment step includes
A first step of electrolysis for 10 to 120 seconds at a voltage of 0 to 15 V in a state where the metal material is immersed in the composition of any one of the inventions (1) to (7);
In the state where the metal material is immersed in the composition according to any one of the inventions (1) to (7), electrolysis is performed at a voltage of 50 to 300 V for 30 to 300 seconds. Wherein the second step is carried out in the same bath subsequent to the first step or in a separate bath different from the first step. is there. Here, the “voltages X to Y (V)” in the first step and the second step may be a mode in which a constant voltage is applied within the range of the voltages X to Y or a mode in which the applied voltage is changed over time. In addition, the lower limit “0V” of “voltage 0 to 15V” in the first step means a voltage at a predetermined time in a mode in which the applied voltage is changed over time, not in a mode with a constant voltage.

  In the present invention (10), the metal Bi and the oxidized Bi formed by the method of the invention (8) or (9) are deposited as Bi in an amount of 20 to 500 mg / m2, the total film thickness is 5 to 40 μm, and The Bi adhesion distribution (G) on the metal material side from the center of the film thickness is a Bi adhesion distribution that is 55% or more (G / H ≧ 55%) with respect to the total Bi adhesion quantity (H). It is a metal surface treatment film.

FIG. 1 is an EPMA line analysis profile of the film in Example 1. FIG. 2 is a diagram showing appropriate ranges of Al ion concentration and pH.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, the metal surface treatment composition according to the best mode, the metal surface treatment method using the composition, and the metal surface treatment film formed by the method will be described in order.

<Metal surface treatment composition>
The composition for metal surface treatment according to the present invention comprises 5 to 30% by weight of an aqueous resin, 100 to 5000 ppm of trivalent Bi ions, and 0.1 to 5 times molar concentration of aminopolycarboxylic acid with respect to Bi ions. And at least a portion of the aqueous resin is a nonionic and / or cationic resin having a predetermined substituent. Hereinafter, each component which comprises this composition is explained in full detail.

<Composition component: Water-based resin>
The aqueous resin according to the present invention is preferably a nonionic resin and a cationic resin. In addition, a curing agent such as a blocked polyisocyanate can be arbitrarily added to the water-based resin. Here, at least a part of the aqueous resin is represented by the following formula (1):
{Wherein R1 and R2 are independently of each other-(R) m-X (where R is an alkylene group having 1 to 6 carbon atoms, m is 1 or 0, and X is And a nonionic and / or cationic resin having a nitrogen-containing group capable of forming a chelate with Bi ion in the polymer skeleton, represented by hydrogen, carboxyl, hydroxyl or acyl. Is a generic term for water-dispersed emulsions and water-soluble resins, wherein R in acyl may be aliphatic or aromatic, and preferably has 1 to 6 carbon atoms.

  Here, in formula (1), R1 and R2 are independently of each other hydrogen, alkyl, hydroxyalkyl, carboxyalkyl or alkylcarbonyl, wherein alkyl, hydroxyalkyl, carboxyalkyl and alkylcarbonyl alkyl The moiety is preferably a linear, branched or cyclic group having 1 to 6 carbon atoms. Among these, those containing O (oxygen atom) are preferable from the viewpoint of chelate forming ability, and hydroxyalkyl is most preferable in view of the ease of synthesis.

  The nitrogen-containing group represented by the formula (1) is present in the polymer backbone of the nonionic and / or cationic resin. Here, the nonionic resin and / or the cationic resin are not particularly limited, and examples thereof include an epoxy resin, a urethane resin, and an acrylic resin. Among these, epoxy resins are preferable, modified epoxy resins are more preferable, and bisphenol A type modified epoxy resins are particularly preferable.

  Here, in order to impart cationicity to the resin, typically, a method of introducing an amino group into the resin skeleton (especially the terminal) (for example, in an epoxy resin, an amino group-containing compound is added to the terminal glycidyl group). Method). This will be described in detail later.

  Moreover, in order to provide nonionic property to resin, the compound containing an ethylene oxide group can also be introduce | transduced, for example. By introducing this, this ethylene oxide group has a nonionic activator function, and effects such as improvement of emulsion stability when it is in an emulsion state can be obtained. Specifically, by reacting polyethylene glycol or polyethylene glycol diglycidyl ether, the properties of the nonionic resin are exhibited. When a bisphenol A-type modified epoxy resin is used, it is preferable to use a bisphenol A ethylene oxide adduct having the same bisphenol A structure.

  Hereinafter, an aminated product of a modified epoxy resin of bisphenol A type that is particularly suitable as a cationic resin will be described in detail.

(Aminated product of modified epoxy resin of bisphenol A type)
Here, a particularly preferred aminated product of the modified bisphenol A-type epoxy resin (A) will be described. The bisphenol A-type modified epoxy resin includes, as raw materials, a modified resin (B), an epoxy resin (C) having an epoxy equivalent of 180 to 2500, a phenol compound (D) having the nitrogen-containing group, and a secondary amino group-containing compound (F ) Or further using bisphenol A (E) and reacting these, an aminated product of a modified epoxy resin. Hereinafter, each component will be described.

* Raw material of modified epoxy resin (A) of bisphenol A type First, a polyol compound is usually used as the modified resin (B). These are applied for the purpose of improving the plasticity of the epoxy resin. Specific examples thereof include polyol resins such as polyester polyol, polyether polyol, polyurethane polyol, and acrylic polyol, and aromatic condensed compounds having a hydroxyl group by adding phenol to the terminal. More specifically, polycaprolactone diol, polyethylene glycol, polypropylene glycol, xylene formaldehyde resin having a phenolic hydroxyl group and the like can be mentioned. The modification with these compounds is a technique that has been used conventionally since the hydroxyl groups of these compounds and the glycidyl ether portion of the epoxy resin can easily react. In the modified epoxy resin, these modified resins are contained in an amount of 5 to 30% by weight.

  Next, as an epoxy resin (C) having an epoxy equivalent of 180 to 2500, an epoxy resin obtained by a reaction between a polyphenol compound and an epihalohydrin, for example, epichlorohydrin, is particularly preferable from the viewpoint of the corrosion resistance of the coating film. Of these, bisphenol A diglycidyl ether obtained by reaction of bisphenol A and epichlorohydrin is most suitable. In addition, an epoxy resin obtained by polymerizing bisphenol A as a basic structure also exhibits the same effect, and an epoxy equivalent of 180 to 2500, preferably 180 to 2000, and more preferably 180 to 1500 is optimal. In the modified epoxy resin, these epoxy resins are contained in an amount of 5 to 30% by weight.

Next, as the phenol compound (D) having the nitrogen-containing group, the following formula (2):
(Formula 6)
(Wherein R3 is the nitrogen-containing group or hydrogen atom, at least one of R3 is the nitrogen-containing group; R4 is independently hydrogen or an alkyl group having 1 to 2 carbon atoms. It is preferable that it is an amine addition phenol compound shown by this. Of these, those having an addition number of R3 of 1 are preferred. When R4 has 1 carbon, that is, a bisphenol A type is preferable. In the modified epoxy resin, 5 to 30% by weight of the phenol compound having a nitrogen-containing group is contained. These can be obtained by synthesizing a diphenol compound by a Mannich reaction between a carbonyl compound and a primary or secondary amine. At this time, formaldehyde is generally used as the carbonyl compound. Primary and secondary amines include ammonia; mono- or di-alkylamines such as monomethylamine, dimethylamine, monoethylamine, diethylamine, monoisopropylamine, diisopropylamine, monobutylamine, dibutylamine; monoethanolamine, Alkanolamines such as diethanolamine, mono (2-hydroxypropyl) amine, di (2-hydroxypropyl) amine, tri (2-hydroxypropyl) amine, monomethylaminoethanol, monoethylaminoethanol; N-formylmethylamine, N- Formylethylamine, acetamide, N-methylacetamide, N-ethylacetamide, propionic acid amide, N-methylpropionamide, N-ethylpropyleneamide, glycine, sarcosine Amine and the like containing carboxyl group or an acyl group and the like.

  Next, the content (addition amount) of bisphenol A (E) can be changed at an arbitrary ratio in relation to the content (addition amount) of the phenol compound (D) having the nitrogen-containing group. In the modified epoxy resin, 5 to 30% by weight is contained as the total amount of both.

  Next, the secondary amino group-containing compound (F) is a cationic property-imparting component for introducing an amino group into an epoxy resin substrate to cationize the epoxy resin. The effect is different. The amine used here contains at least one active hydrogen that reacts with an epoxy group. Examples of the amino group-containing compound used for such purpose include mono- or di-alkylamines such as monomethylamine, dimethylamine, monoethylamine, diethylamine, monoisopropylamine, diisopropylamine, monobutylamine, and dibutylamine. Alkanolamines such as monoethanolamine, diethanolamine, mono (2-hydroxypropyl) amine, di (2-hydroxypropyl) amine, tri (2-hydroxypropyl) amine, monomethylaminoethanol, monoethylaminoethanol; ethylenediamine, propylene Diamine, Butylenediamine, Hexamethylenediamine, Tetraethylenepentamine, Pentaethylenehexamine, Diethylaminopropylamine, Diethylenetriamine Alkylene polyamine and ketimine of the polyamines such as triethylenetetramine; ethyleneimine, alkylene imine such as propylene imine; piperazine, a cyclic amine such as morpholine, and the like. In the modified epoxy resin, the secondary amino group-containing compound (F) is contained in an amount of 0.5 to 20% by weight.

* Production method of aminated product of bisphenol A modified epoxy resin First, a predetermined amount of modified resin (B), epoxy resin (C), phenol compound (D) having the nitrogen-containing group, and bisphenol A (E) are mixed. And stirring with heating. The heating temperature is preferably 70 to 100 ° C. After each raw material is dissolved, a catalyst is added, the heating temperature is increased, and synthesis is performed. As the catalyst, a tertiary amine such as dimethylbenzylamine is usually used. In general, the synthesis temperature is controlled at 120 ° C to 150 ° C.

  By adjusting the synthesis temperature and time, an epoxy resin having a predetermined epoxy equivalent can be synthesized. The epoxy equivalent is calculated by the epoxy equivalent measurement defined in JIS K7236. The epoxy equivalent at this time is preferably 800 to 10,000, more preferably 800 to 5000, and most preferably 800 to 3000. The greater the epoxy equivalent, the lower the emulsification stability during emulsion preparation.

  Next, the secondary amino group-containing compound (F) is added to the synthesized modified epoxy resin. While maintaining the modified epoxy resin at 70 ° C. to 110 ° C., the secondary amino group-containing compound (F) is added, and synthesis is performed for 1 to 3 hours to obtain an aminated product of the modified epoxy resin.

<Composition component: Trivalent Bi ion>
Bi ion in the present invention refers to a Bi component that is not solidified in the composition and is in a completely dissolved state. Specifically, the nitrogen-containing group in the aminopolycarboxylic acid or polymer described later is used. This means that the chelate is constituted by a water-soluble state stably.

<Composition component: Aminopolycarboxylic acid>
Aminopolycarboxylic acid is a generic term for chelating agents having an amino group and a plurality of carboxyl groups in the molecule. Specifically, EDTA (ethylenediaminetetraacetic acid), HEDTA (hydroxyethylethylenediaminetriacetic acid), NTA (nitrilotrimethyl). Acetic acid), DTPA (diethylenetriaminepentaacetic acid), TTHA (triethylenetetraminehexaacetic acid) and the like are applicable, and EDTA, HEDTA, and NTA are more preferable from the viewpoint of chelate stability with Bi ions.

<Composition component: Other ingredients>
In the composition of the present invention, additives usually used in the paint field such as a pigment, a catalyst, an organic solvent, a pigment dispersant, and a surfactant can be further applied as necessary. Examples of pigments include colored pigments such as titanium white and carbon black, extender pigments such as clay, talc and barita, rust preventive pigments such as aluminum tripolyphosphate and zinc phosphate, organic tin compounds such as dibutyltin oxide and dioctyltin oxide, Examples thereof include dialkyltin fatty acids such as dibutyltin laurate and dibutyltin dibenzoate, and tin compounds such as aromatic carboxylates. Further, as described later in detail, Al ions may be added from the viewpoint of promoting the precipitation of the aqueous resin (especially in the case of a nonionic resin). Furthermore, even if the composition of the present invention contains metal ions such as Fe ions, Zn ions, and Ce ions in addition to Bi ions and Al ions, the effects of the present invention are not impaired. Rather, these metal ions have the effect of promoting the precipitation of the aqueous resin, although not as much as the Al ions. The Fe ion is more preferably trivalent than divalent.

<Composition component: Liquid medium>
As the liquid medium of the metal surface treatment composition according to the present invention, an aqueous medium is preferable, and water is more preferable. When the liquid medium is water, the liquid medium may contain an aqueous solvent other than water (for example, water-soluble alcohols).

<Composition of composition>
Next, the composition of the metal surface treatment composition according to the present invention will be described.

(Water-based resin)
First, the metal surface treatment composition according to the present invention contains 5 to 30% by weight of an aqueous resin, preferably 10 to 25% by weight, more preferably 10 to 20% by weight, based on the total weight of the composition. Including. Here, the ratio (weight ratio) of the nonionic and / or cationic resin represented by the formula (1) in the total water-based resin is preferably 30 to 100%, and more preferably 70 to 100%. . The smaller the ratio of the resin represented by the formula (1), the lower the chelating ability, and it cannot contribute to the stability of Bi. Further, if the total water-based resin content is too low, the amount of film deposition is insufficient, and if the content is too high, it is economically disadvantageous.

  Here, the molar concentration of the nitrogen-containing group represented by the formula (1) in the metal surface treatment composition according to the present invention is 0.1 to 200 times the trivalent Bi ion, 0 More preferably, it is 5 to 100 times, and more preferably 1.0 to 50 times. The lower the molar concentration, the lower the chelating ability and cannot contribute to the stability of Bi. The higher the molar concentration, the less economical it is.

(Trivalent Bi ion)
Next, the metal surface treatment composition according to the present invention contains 100 to 5000 ppm of trivalent Bi ions. 500 to 4000 ppm is more preferable, and 1000 to 3000 ppm is most preferable. If the Bi ion concentration is too low, a sufficient amount of Bi adhesion necessary for improving the corrosion resistance cannot be obtained. If the Bi ion concentration is too high, the electrical conductivity of the composition becomes too high, and the coating on the metal material having a complicated shape is increased. As a result, the Bi adhesion amount becomes excessive and the film adhesion may be impaired. The Bi ion concentration in the composition can be determined by solid-liquid separation of the composition using an ultracentrifuge, and the liquid phase can be quantified using high frequency inductively coupled plasma emission spectrometry (ICP) or atomic absorption spectrometry (AA). .

(Aminopolycarboxylic acid)
The metal surface treatment composition according to the present invention contains aminopolycarboxylic acid at a molar concentration of 0.1 to 5 times with respect to Bi ions. 0.1-4 times molar concentration is still more preferable, and it is most preferable that it is 0.1-3 times molar concentration. If the concentration ratio with respect to Bi ions is too low, Bi ions are hydrolyzed in the composition and become oxides, so that the effective Bi ion concentration is lowered, and as a result, a sufficient amount of Bi deposition cannot be obtained. On the other hand, if it is too high, Bi ions will be overstabilized and a sufficient amount of Bi will not be obtained. As will be described later, the excessive aminopolycarboxylic acid may cause gelation of the cationic resin, and is incorporated into the coating film during electrolysis, thereby deteriorating the appearance of the coating film.

(Al ion)
Here, the composition according to the present invention contains an aminopolycarboxylic acid, but particularly when combined with a cationic resin, the presence of excess aminopolycarboxylic acid sometimes causes gelation of the cationic resin. There is. In such a case, the amount of the cation group of the cationic resin is reduced or a nonionic resin is used (or the cationic resin and the nonionic resin are mixed, and the total amount of cation groups is relatively reduced. (Decrease) is preferred. By the way, in this case, another problem that the resin does not precipitate so much even when the pH is increased may occur. Here, the problem can be solved by including Al ions. At this time, it is preferable to contain 20 to 500 ppm of Al ions. 50 to 400 ppm is more preferable, and 100 to 300 ppm is most preferable. If the lower limit is not reached, the effect of improving the coating deposition of Al ions becomes insufficient, and if the upper limit is exceeded, the electrical conductivity of the composition becomes excessive, and the throwing power is reduced.

  Here, the mechanism of action of the Al ions described above is as follows. In other words, ionic Al becomes a fine hydroxide colloid due to the increase in pH of the metal surface due to cathode electrolysis, and when it completely loses zeta charge at around pH 9 and begins to agglomerate rapidly, the surrounding resin is also involved and precipitates. Presumed to be.

  A series of reactions from cathodic electrolysis to disappearance of the charge of the hydroxide colloid must be completed instantaneously. If it has become a hydroxide in advance, aggregation starts over time, and the aggregation ability around pH 9 is extremely reduced. Therefore, the Al component in this embodiment must be in the form of ions in the composition.

  In addition, metal ions are usually stabilized by the presence of a chelating agent, but in the case of Al ions, there is no or rare chelating agent that is stable enough to prevent the formation of hydroxide colloid accompanying pH increase. . At least organic acids such as acetic acid, formic acid, sulfamic acid, and lactic acid, and aminopolycarboxylic acids that are usually blended in electrodeposition coating compositions do not have a chelating ability to stabilize Al ions.

  Al ions can be added using an Al compound. The Al compound is not particularly limited, but can be added in the form of an inorganic acid salt such as nitrate or sulfate, or an organic acid salt such as lactate or acetate.

Furthermore, in addition to containing Al ions in the above-mentioned range, it is preferable to satisfy the following calculation formula when the pH of the composition according to this embodiment is defined as A [ppm] Al ion concentration.
3.5 ≦ pH ≦ −Log ((A × 1.93 × 10 ⁻¹⁵ ) ^1/3 )
The following formula is more preferable.
3.6 ≦ pH ≦ −Log ((A × 1.93 × 10 ⁻¹⁵ ) ^1/3 )
The following formula is most preferable.
3.7 ≦ pH ≦ −Log ((A × 1.93 × 10 ⁻¹⁵ ) ^1/3 )
When the pH is lower than the lower limit, the deposition efficiency is lowered and the throwing power is also lowered. When the pH exceeds the upper limit, Al ions cause hydrolysis, which is not preferable.

The term -Log ((A × 1.93 × 10 ⁻¹⁵ ) ^1/3 ) is obtained from the solubility product of Al hydroxide at 25 ° C .: 1.92 × 10 ⁻³² . That is, when the pH is exceeded, Al ions precipitate as hydroxides and can no longer be ions. Here, 25 ° C. is a typical temperature during storage and use of the composition.

  Further, the effects of the present invention are not impaired even if the composition of the present invention contains metal ions such as Fe ions, Zn ions, and Ce ions in addition to Bi ions and Al ions. Rather, these metal ions have the effect of promoting the precipitation of the aqueous resin, although not as much as the Al ions. The Fe ion is more preferably trivalent than divalent.

  For reference, the appropriate range of Al ion concentration and pH is shown in FIG.

<Physical properties of metal surface treatment composition>
(PH)
The pH of the metal surface treatment composition according to the present invention is not particularly limited, but is usually adjusted to a range of 2.0 to 7.0, preferably 3.0 to 6.5. it can.

(temperature)
Although there is no restriction | limiting in particular also about the temperature of the metal surface treatment composition which concerns on this invention, When depositing a film | membrane by electrolytic treatment, it is normally used in 15-40 degreeC, Preferably it is used within the range of 20-35 degreeC. it can.

<< Method for producing metal surface treatment composition >>
Next, a method for producing a metal surface treatment composition according to the present invention will be described. The case where an aminated product of a modified epoxy resin is used as the aqueous resin will be described as an example. First, a neutralized acid is added to the synthesized aminated product of the modified epoxy resin, mixed with stirring, and then diluted with water to prepare a resin emulsion having a predetermined concentration. As the neutralizing acid, formic acid, acetic acid, lactic acid, sulfamic acid and the like are used.

  At this time, it is preferable to add a curing agent, a curing catalyst, an organic solvent, etc. before adding the neutralizing acid. By adding in advance, a uniform emulsion can be obtained.

  As the curing agent, a block polyisocyanate is generally used. Block polyisocyanate is an addition reaction product of approximately the theoretical amount of a polyisocyanate compound and an isocyanate blocking agent. Examples of the polyisocyanate compound used here include tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, diphenylmethane-2,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate (usually referred to as “MDI”), Aromatic, aliphatic or alicyclic polyisocyanate compounds such as crude MDI, bis (isocyanate methyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, isophorone diisocyanate; cyclized polymers of these polyisocyanate compounds; Isocyanate biuret; ethylene glycol, propylene glycol, trimethylolpropane in excess of these isocyanate compounds Hexanetriol, and the like terminal isocyanate-containing compounds obtained by reacting a low molecular weight active hydrogen-containing compounds such as castor oil. These can be used alone or in combination of two or more.

  On the other hand, the isocyanate blocking agent is blocked by adding to the isocyanate group of the polyisocyanate compound, and the blocked polyisocyanate compound produced by the addition is stable at room temperature, but the baking temperature of the coating film (usually about 100). When heated to about 200 ° C., it is desirable that the blocking agent can be dissociated to regenerate free isocyanate groups.

  Examples of the blocking agent that satisfies such requirements include lactam compounds such as ε-caprolactam and γ-butyrolactam; oxime compounds such as methyl ethyl ketoxime and cyclohexanone oxime; phenols such as phenol, para-t-butylphenol, and cresol. Compounds; aliphatic alcohols such as n-butanol and 2-ethylhexanol; aromatic alkyl alcohols such as phenyl carbinol and methyl phenyl carbinol; ether alcohol compounds such as ethylene glycol monobutyl ether and diethylene glycol monoethyl ether Can be mentioned. These blocking agents can be used alone or in combination of two or more. In addition, in order to efficiently advance the dissociation and curing reaction of the blocking agent, and to generate the intended curing reaction product, a part of the isocyanate group is added to the modified epoxy resin skeleton in advance, and the remaining isocyanate A method of blocking a group with a blocking agent is used.

  Next, a Bi ion aqueous solution is added to the obtained emulsion. The Bi ion aqueous solution can be obtained by dissolving a polyaminocarboxylic acid having a predetermined concentration in water, adding bismuth nitrate pentahydrate thereto, and stirring the mixture at 50 to 70 ° C. until dissolved.

  Usually, a pigment is added here for improving the coating film performance or coloring. As the pigment, a dispersion resin is used, and a dispersion (paste) is used in advance.

  A product obtained by sufficiently stirring these is a metal surface treatment composition.

<< Usage method of metal surface treatment composition (application) >>
(Applicable)
The metal surface treatment composition according to the present invention is used for the purpose of preventing various metals from corrosion. The metal material is not particularly limited, but steel materials such as cold-rolled steel plates, hot-rolled steel plates, cast materials, steel pipes, etc., and zinc-based plating treatment and / or aluminum-based plating are performed on those steel materials. Materials, aluminum alloy plates, aluminum castings, magnesium alloy plates, magnesium castings, and the like. It is particularly suitable for use in metal structures having complicated shapes, for example, automobile bodies, automobile parts, home appliances, building materials, etc., which are metal structures mainly composed of iron-based materials.

(Usage method <metal surface treatment method>)
The usage method (metal surface treatment method) according to the present invention includes a step of depositing a coating film on the surface of a metal material in an electrolytic treatment step using the above-described metal surface treatment composition as a cathode. More preferably, the method of use (metal surface treatment method) according to the present invention comprises an electrolytic treatment step of performing electrolytic treatment on a metal material whose surface has been cleaned in order to deposit a film on the metal material; It includes a water washing and baking process performed after the treatment process. Hereinafter, the electrolytic treatment process characteristic of this method will be described in detail.

  The electrolytic treatment step (cathode electrolysis) includes a first step of electrolysis at a voltage of 0 to 15 V for 10 to 120 seconds in a state where the metal material is immersed in a metal surface treatment composition, and a metal surface treatment composition. A second step performed after the first step, in which the metal material is immersed in an object and electrolyzed at a voltage of 50 to 300 V for 30 to 300 seconds, wherein the second step includes: Following the first step, it is carried out in the same bath or in a different bath different from the first step.

  Here, a 1st process is a process mainly performed in order to adhere Bi preferentially, and a 2nd process is a process mainly performed in order to precipitate resin preferentially. In order to obtain sufficient corrosion resistance, Bi that is in direct contact with the metal material, that is, the presence of the interface Bi that exists at the interface between the metal material and the film is necessary. For this purpose, the order of the first step and the second step is required. And conditions are extremely important.

  The voltage of a 1st process is 0-15V, and it is preferable to electrolyze for 10 to 120 seconds. When the voltage is lower than the lower limit, that is, when electrolysis is performed using the metal material as an anode, the metal material is eluted in the composition, not only reducing the stability of the composition, but also the interface Bi necessary for improving the corrosion resistance. It will not adhere sufficiently. Even when the upper limit is exceeded, resin deposition starts before Bi is preferentially deposited on the metal surface, so that sufficient corrosion resistance cannot be obtained.

  Even when the treatment time is less than the lower limit, sufficient interface Bi is not deposited, and when the treatment time is more than the upper limit, the adhesion amount of the interface Bi becomes excessive, and the adhesion of the film may be impaired.

  The voltage in the second step is 50 to 300 V, and electrolysis is preferably performed for 30 to 300 seconds. When the voltage is lower than the lower limit, the amount of the resin film deposited is insufficient. When the voltage is higher than the upper limit, the resin film is excessively deposited, which is economically disadvantageous, and the finished appearance of the film may be impaired.

  When shifting from the first step to the second step, there is no need to increase the voltage instantaneously, and even if it is gradually increased, the effect of the present invention is not impaired.

  Furthermore, the two-stage electrolytic treatment in the present invention is not necessarily performed in the same tank, and may be performed in different tanks. When the two-stage electrolytic treatment is performed in two tanks, it is possible to adjust the Bi concentration and the resin concentration in accordance with the first stroke and the second stroke in the first tank and the second tank, thereby achieving cost merit. For example, by reducing the Bi concentration in the second tank, the amount of Bi contained in the carry-out liquid can be reduced, leading to cost reduction.

<Metal surface treatment film>
The metal surface treatment film according to the present invention is obtained by the treatment method of the present invention using the metal surface treatment composition of the present invention. Here, Bi which exists in a film | membrane exists with the form of a metal and an oxide. Bi deposited by cathodic electrolysis is basically reduced Bi metal Bi, but a part of it is oxidized in particular in the coating baking process to become an oxide. In addition, when a high voltage is applied in the second step, Bi stabilization by the aminopolycarboxylic acid is insufficient due to an increase in pH on the surface of the film, so that it also precipitates as oxidized Bi especially on the film surface side.

  The Bi adhesion amount is preferably 20 to 500 mg / m2, more preferably 30 to 400 mg / m2, and most preferably 50 to 300 mg / m2. If the amount of Bi deposited is too low, sufficient corrosion resistance cannot be obtained. If it is too high, improvement in corrosion resistance can no longer be expected, and film adhesion may be impaired. The amount of Bi attached can be determined by fluorescent X-ray spectroscopic analysis. The “metal Bi adhesion amount” and “oxidized Bi adhesion amount” in the claims and in the present specification are values determined by the fluorescent X-ray spectroscopic analysis. In addition, the presence of hydroxides cannot be denied as other forms, but when quantified as “metal Bi” or “oxidized Bi” by the measurement method, the numerical value is “metal Bi adhesion amount” or “oxidized Bi”. It shall be referred to as “attachment amount”.

  The total film thickness of the obtained film is preferably 5 to 40 μm, more preferably 5 to 30 μm, and most preferably 7 to 25 μm. If it is too thin, sufficient corrosion resistance cannot be obtained, and if it is too thick, not only is it economically disadvantageous, but the throwing power may be lowered. The film thickness can be measured by an electromagnetic induction type film thickness meter if the base metal is a magnetic metal, or by an eddy current film thickness meter if the base metal is a non-magnetic metal.

  Bi in the film needs to be present more on the base metal side than the film surface. Specifically, the Bi adhesion amount B on the metal material side from the center of the film thickness is a Bi adhesion distribution in which the total Bi adhesion amount: 55% or more (B / A ≧ 55%) with respect to A. preferable. It is more preferably 58% or more, and most preferably 60% or more. If it is too low, sufficient corrosion resistance cannot be obtained. Note that if it exceeds 90%, the Bi concentration on the surface side of the film is extremely lowered and the function of Bi as a curing catalyst is lost.

  The distribution of Bi adhesion in the film can be measured by line analysis of the film cross section using EPMA. The position of the base metal / film interface and the film surface is specified from the backscattered electron image taken at the same time, and the integrated value of Bi intensity in the film by EPMA line analysis: the integrated value of only the base metal side from the center of A and film thickness: B can be obtained and B / A can be calculated.

Synthesis of Phenol Compound (D) Bisphenol A (Wako Pure Chemical): 264.8 g was completely dissolved in a mixed solvent of butyl cellosolve (Wako Pure Chemical): 100 g and ethanol (Pure Chemical): 100 g, and then diethanolamine (Wako Pure) Drug): 121.8 g, formaldehyde solution (Pure Chemical): 96.8 g were added and heated to 75 ° C. Stirring was performed for 4 days at 75 ° C., and then the solvent was removed by an evaporator to obtain a phenol compound (D1). From the NMR analysis, it was confirmed that the structure of the compound obtained at this time was Formula 3.
(Formula 7)

Bisphenol A (Wako Pure Chemical Industries): 264.8 g was completely dissolved in a mixed solvent of butyl cellosolve (Wako Pure Chemical Industries): 100 g and ethanol (Pure Chemical): 100 g, and then glycine (Tokyo Kasei): 87.1 g, formaldehyde Liquid (Pure Chemical): 96.8 g was added and heated to 75 ° C. Stirring was performed at 75 ° C. for 6 days, and then the solvent was removed by an evaporator to obtain a phenol compound (D2). From the NMR analysis, it was confirmed that the structure of the compound obtained at this time was Formula 4.
(Formula 8)

Bisphenol A (Wako Pure Chemical Industries): 264.8 g was completely dissolved in a mixed solvent of butyl cellosolve (Wako Pure Chemical Industries): 100 g and ethanol (Pure Chemical): 100 g, then acetylethylamine (Tokyo Kasei): 101.1 g, Formaldehyde solution (Pure Chemical): 96.8 g was added and heated to 75 ° C. Stirring was performed for 6 days at 75 ° C., and then the solvent was removed by an evaporator to obtain a phenol compound (D3). From the NMR analysis, it was confirmed that the structure of the compound obtained at this time was Formula 5.
(Formula 9)

Bisphenol A (Wako Pure Chemical Industries): 264.8 g was completely dissolved in a mixed solvent of butyl cellosolve (Wako Pure Chemical Industries): 100 g and ethanol (Pure Chemical): 100 g, then diethylamine (Tokyo Kasei): 84.8 g, formaldehyde Liquid (Pure Chemical): 96.8 g was added and heated to 75 ° C. Stirring was performed for 4 days at 75 ° C., and then the solvent was removed with an evaporator to obtain a phenol compound (D4). From the NMR analysis, it was confirmed that the structure of the compound obtained at this time was Formula 6.
(Formula 10)

Bisphenol A (Wako Pure Chemical Industries): 264.8 g was completely dissolved in a mixed solvent of butyl cellosolve (Wako Pure Chemical Industries): 100 g and ethanol (Pure Chemical): 100 g, and then ethylamine (methanol solution) (Tokyo Kasei): 149 .4 g, formaldehyde solution (Pure Chemical): 96.8 g was added and heated to 75 ° C. Stirring was performed for 6 days at 75 ° C., and then the solvent was removed by an evaporator to obtain a phenol compound (D5). From the NMR analysis, it was confirmed that the structure of the compound obtained at this time was Formula 7.
(Formula 11)

Bisphenol A (Wako Pure Chemical Industries): 264.8 g was completely dissolved in a mixed solvent of butyl cellosolve (Wako Pure Chemical Industries): 100 g and ethanol (Pure Chemical): 100 g, then ammonia (ethanol solution) (Tokyo Kasei): 580 0.0 g, formaldehyde solution (Pure Chemical): 96.8 g was added and heated to 75 ° C. Stirring was performed for 6 days at 75 ° C., and then the solvent was removed with an evaporator to obtain a phenol compound (D6). From the NMR analysis, it was confirmed that the structure of the compound obtained at this time was Formula 8.
(Formula 12)

Confirmation of Bi ion chelating ability Bi ion aqueous solution (B2, see below): To 100 g, 1.7 g of phenol compound (D1) previously dissolved in 50 g of ethanol was added and stirred while heating to 60 ° C. About the obtained solution, it has confirmed that the phenolic compound (D1) was chelating Bi by using a liquid chromatography mass spectrometry. In this case, the phenol compound (D1) has a molar concentration of 1.0 times that of Bi.

  Bi ion aqueous solution (B2, see below): A solvent solution of 1.1 g of bisphenol A dissolved in 50 g of ethanol in advance was added to 100 g, and the mixture was stirred while heating to 60 ° C. By using liquid chromatography mass spectrometry for the resulting solution, it was confirmed that bisphenol A did not chelate Bi. In this case, bisphenol A has a molar concentration of 1.0 times that of Bi.

  Bi ion aqueous solution (B2, see below): 1.5 g of phenol compound (D2) previously dissolved in 50 g of ethanol was added to 100 g, and the mixture was stirred while heating to 60 ° C. About the obtained solution, it was able to confirm that the phenol compound (D2) was chelating Bi by using liquid chromatography mass spectrometry. In this case, the phenol compound (D2) has a molar concentration of 1.0 times that of Bi.

  Bi ion aqueous solution (B2, see below): 100 g of phenol compound (D3) previously dissolved in 50 g of ethanol: 1.6 g was added, and the mixture was stirred while heating to 60 ° C. About the obtained solution, it was able to confirm that the phenol compound (D3) was chelating Bi by using a liquid chromatography mass spectrometry. In this case, the phenol compound (D3) has a molar concentration of 1.0 times that of Bi.

  Bi ion aqueous solution (B2, see below): Phenol compound (D4) dissolved in ethanol 50 g in advance: 100 g was added to 100 g, followed by stirring while heating to 60 ° C. About the obtained solution, it was able to confirm that the phenol compound (D4) was chelating Bi by using a liquid chromatography mass spectrometry. In this case, the phenol compound (D4) has a molar concentration of 1.0 times that of Bi.

  Bi ion aqueous solution (B2, see below): Phenol compound (D5): 1.4 g dissolved in ethanol 50 g in advance was added to 100 g, and the mixture was stirred while warming to 60 ° C. About the obtained solution, it was able to confirm that the phenol compound (D5) was chelating Bi by using a liquid chromatography mass spectrometry. In this case, the phenol compound (D5) has a molar concentration of 1.0 times that of Bi.

  Bi ion aqueous solution (B2, see below): 1.2 g of phenol compound (D6) dissolved in 50 g of ethanol in advance was added to 100 g, and the mixture was stirred while heating to 60 ° C. About the obtained solution, it was able to confirm that the phenol compound (D6) was chelating Bi by using a liquid chromatography mass spectrometry. In this case, the phenol compound (D6) has a molar concentration of 1.0 times that of Bi.

Preparation of blocked isocyanate Cosmonate M200 (manufactured by Mitsui Chemicals Co., Ltd.): 115.6 g of methyl isobutyl ketone was added to 678.4 g, the temperature was raised to 70 ° C., and then 706.0 g of diethylene glycol monoethyl ether was slowly added dropwise. After completion of the dropping, the temperature was raised to 90 ° C. The reaction was carried out at 90 ° C. for 12 hours to obtain a blocked isocyanate. When infrared absorption spectrum measurement was performed, absorption derived from unreacted isocyanate groups was not observed, and it was confirmed that the isocyanate was completely blocked.

Production of water-based resin emulsion Production Example 1
Epoxy resin # 828 (manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent: 180): 114.0 g in a 1000 ml separable flask equipped with a thermometer, condenser, and stirrer, polycaprolactone diol Plaxel 208 (Daicel Chemical Co., Ltd.) as a modified resin 41.5 g, bisphenol A: 45.6 g, and 0.1 g of dimethylbenzylamine were added, and the reaction was performed at 130 ° C. until the epoxy equivalent was 1000. After completion of the reaction, 55.5 g of butyl cellosolve was added, and 12.6 g of diethanolamine and 8.0 g of diethylenetriamine ketimine were added, and the reaction was carried out at 90 ° C. for 2 hours. To this was added blocked isocyanate: 105.5 g, dibutyltin diacetate: 3.2 g, and acetic acid 5.4 g. After stirring until uniform, 578.1 g of deionized water was vigorously stirred for about 1 hour. To obtain an aqueous resin emulsion (A1) having a solid content concentration of 33%.

Production Example 2
In Production Example 1, in place of bisphenol A, 31.9 g of bisphenol A and 20.8 g of phenol compound (D1) were used, and a similar reaction was performed to obtain an aqueous resin emulsion (A2).

Production Example 3
In Production Example 1, instead of bisphenol A, 13.7 g of bisphenol A and 48.4 g of phenol compound (D1) were used, and a similar reaction was performed to obtain an aqueous resin emulsion (A3).

Production Example 4
Similarly, bisphenol A: 31.9 g and D2: 19.0 g were used in place of bisphenol A, and a similar reaction was carried out to obtain an aqueous resin emulsion (A4).

Production Example 5
Similarly, bisphenol A: 31.9 g and D3: 19.7 g were used in place of bisphenol A, and a similar reaction was carried out to obtain an aqueous resin emulsion (A5).

Production Example 6
Similarly, bisphenol A: 22.8 g and D4: 18.9 g were used instead of bisphenol A, and a similar reaction was carried out to obtain an aqueous resin emulsion (A6).

Production Example 7
Similarly, bisphenol A: 22.8 g and D5: 17.2 g were used in place of bisphenol A, and the same reaction was performed to obtain an aqueous resin emulsion (A7).

Production Example 8
Similarly, bisphenol A: 22.8 g and D6: 15.5 g were used instead of bisphenol A, and a similar reaction was carried out to obtain an aqueous resin emulsion (A8).

Production Example 9
Epoxy resin # 828 (manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent: 180): 114.0 g in a 2000 ml separable flask equipped with a thermometer, condenser and stirrer, polycaprolactone diol Plaxel 208 (Daicel Chemical Co., Ltd.) 41.5 g, bisphenol A: 31.9 g, phenol compound (D1): 20.8 g, bisphenol A ethylene oxide adduct / New Pole BPE-100 (manufactured by Sanyo Chemical Industries): 100.2 g, 0.1 g of dimethylbenzylamine was added, and the reaction was carried out at 130 ° C. until the epoxy equivalent reached 1500. After the reaction, 75.3 g of butyl cellosolve was added. Blocked isocyanate: 143.4 g and dibutyltin diacetate: 4.3 g were added and stirred until uniform, and 792.9 g of deionized water was added dropwise over about 1 hour with vigorous stirring. An aqueous resin emulsion (A9) having a solid content concentration of 33% was obtained.

Preparation of pigment paste To 8.3 parts of 60% quaternary chloroepoxy resin, 7.0 parts of purified clay, 0.3 parts of carbon black, 3.0 parts of zinc phosphate and deionized water were added to a ball mill. For 20 hours to obtain a pigment dispersion paste having a solid content of 50% by weight.

Preparation of Bi ionic liquid Distilled water: HEDTA: 13.3 g was dissolved in 500 g, heated to 60 ° C., and then bismuth nitrate pentahydrate: 23.2 g was added to completely dissolve the solid content. Stir until Distilled water was further added so that the total amount was finally 1.0 L, and Bi ion aqueous solution (B1) was produced. In this case, HEDTA has a molar concentration of 1.0 times that of Bi.
Distilled water: 6.65 g of HEDTA was dissolved in 500 g and heated to 60 ° C., and then bismuth nitrate pentahydrate: 23.2 g was added and stirred. Distilled water was further added so that the total amount was finally 1.0 L, and a thin turbid Bi ionic liquid (B2) was produced. In this case, HEDTA is 0.5 times the molar concentration of Bi.
Distilled water: 2.66 g of HEDTA was dissolved in 500 g, heated to 60 ° C., bismuth nitrate pentahydrate: 23.2 g was added and stirred. Distilled water was further added so that the total amount became 1.0 L finally, and a cloudy Bi ionic liquid (B3) was produced. In this case, HEDTA has a molar concentration of 0.2 times that of Bi.
After dissolving 1.33 g of HEDTA in 500 g of distilled water and heating to 60 ° C., 23.2 g of bismuth nitrate pentahydrate was added and stirred. Distilled water was further added so that the total amount was finally 1.0 L, and a thick and turbid Bi ionic liquid (B4) was produced. In this case, HEDTA has a molar concentration of 0.1 times that of Bi.
EDTA: 6.99 g was dissolved in distilled water: 500 g, heated to 60 ° C., bismuth nitrate pentahydrate: 23.2 g was added, and the mixture was stirred until the solid content was completely dissolved. Distilled water was further added so that the total amount was finally 1.0 L, and Bi ion aqueous solution (B5) was produced. In this case, EDTA is 0.5 times the molar concentration of Bi.
Distilled water: NTA: 45.8 g was dissolved in 500 g, heated to 60 ° C., bismuth nitrate pentahydrate: 23.2 g was added, and the mixture was stirred until the solid content was completely dissolved. Distilled water was further added so that the total amount finally became 1.0 L, and Bi ion aqueous solution (B6) was produced. In this case, NTA has a molar concentration of 5.0 times that of Bi.

Preparation of composition A pigment dispersion paste and Bi additive in an amount of 4.0% by weight of an inorganic solid are blended in a resin emulsion in an amount of 16.0% by weight of the combination shown in Table 1, and a composition is prepared. Was made. Each concentration was adjusted by diluting with deionized water. In Examples 1 to 11 and Comparative Examples 1 and 2, the pH of the treatment liquid was 5. About Example 12, it adjusted to Al concentration: 200ppm and pH4 using the aluminum nitrate nonahydrate and nitric acid.

Electrolytic conditions After electrolysis at 8V for 60 seconds as an electrolytic step (1), an electrolytic treatment was immediately performed at 180V for 180 seconds as an electrolytic step (2).

As a test plate , a cold rolled steel plate: SPCC (JIS 3141) 70 × 150 × 0.8 mm (hereinafter abbreviated as SPC) is used, and its surface is preliminarily strong alkaline degreasing agent “FC-E2001” manufactured by Nihon Parkerizing Co., Ltd. Was degreased by spraying for 120 seconds. After the degreasing treatment, it was washed with spray water for 30 seconds, immersed in the compositions shown in Examples and Comparative Examples, and subjected to cathode electrolytic treatment under the electrolytic conditions shown in Examples and Comparative Examples. The test plate after completion of electrolysis was immediately rinsed with deionized water for 30 seconds and baked at 180 ° C. for 20 minutes in an electric oven.

Investigation of film characteristics The film characteristics of the film deposited on the test plate were investigated by the following method.
Film thickness measurement: Measured using an electromagnetic induction film thickness meter.
Bi adhesion amount: quantified by fluorescent X-ray spectroscopic analysis.
Bi adhesion distribution: Sample cross section was analyzed by EPMA line analysis. See below for specific methods.

  Bi adhesion amount distribution measurement in the film was analyzed using EPMA. The metal material after the film treatment was fixed with an embedded resin, the cross section was polished, and a line analysis profile of Bi was obtained from the base metal direction to the deposited film surface direction. A line analysis profile is an average value of characteristic X-ray intensity calculated in an arbitrary width in the one-dimensional direction of an analysis area based on mapping analysis data, and can be interpreted as a line analysis having a width. The measurement conditions are as follows.

Measuring instrument: EPMA-1610 electron gun manufactured by Shimadzu Corporation: CeB6 cathode beam current: 50 nA, beam voltage: 15 kV, beam diameter: 1 μmφ or less Integration number: once, sampling time per point: 100 ms
Spectroscopic crystal: PET (Bi Mα)

The position of the interface between the base metal and the film and the surface of the film is identified from the backscattered electron image taken at the same time, and the integrated value of Bi intensity in the film: A and the integrated value only on the base metal side from the center of the film thickness: B are obtained, B / A was calculated.
For reference, FIG. 1 shows the analysis result of the film obtained in Example 1 as a representative profile.

Corrosion resistance test method and evaluation method A cross-cut was applied to a resin-coated plate produced by cathodic electrolysis, a salt spray test (JIS-Z2371) was performed, and the maximum swell width on one side of the cross-cut portion after 1500 hours was measured. Based on the measurement results, the evaluation was made with less than 2 mm: ◎, 2 mm or more and less than 3 mm: ○, 3 mm or more and less than 4 mm: Δ, 4 mm or more: x. The results are shown in Table 2.

Appearance test method and evaluation method The glossiness of a resin-coated plate produced by cathodic electrolysis was measured.
Gloss meter: Nippon Denshoku Industries Co., Ltd. VG2000
Measurement angle: 60 °
Based on the measurement results, the evaluation was 65 or more: ○, less than 65: x. The results are shown in Table 2.

Claims (10)

Containing 5 to 30 wt% of an aqueous resin, 100 to 5000 ppm of trivalent Bi ions, and 0.1 to 5 times the molar concentration of aminopolycarboxylic acid with respect to Bi ions,
At least a part of the water-based resin is represented by the following formula (1):
{Wherein R1 and R2 are independently of each other-(R) m-X (where R is an alkylene group having 1 to 6 carbon atoms, m is 1 or 0, and X is A metal surface treatment characterized by being a nonionic and / or cationic resin having a nitrogen-containing group capable of forming a chelate with Bi ions in the polymer skeleton, represented by hydrogen, carboxyl, hydroxyl or acyl} Composition.   In formula (1), R1 and R2 are independently of each other hydrogen, alkyl, hydroxyalkyl, carboxyalkyl or alkylcarbonyl, wherein the alkyl portion of alkyl, hydroxyalkyl, carboxyalkyl and alkylcarbonyl is The composition for metal surface treatment according to claim 1, which is linear, branched or cyclic having 1 to 6 carbon atoms.   The metal surface treatment composition according to claim 1 or 2, wherein the aqueous resin is a modified epoxy resin.   The metal surface treatment according to claim 3, wherein the modified epoxy resin is bisphenol A type, and the nitrogen-containing group is directly bonded to the benzene ring portion of the phenylene group instead of the glycidyl ether portion in the modified epoxy resin. Composition.   The bisphenol A-type modified epoxy resin (A) uses, as raw materials, the modified resin (B), the epoxy resin (C) having an epoxy equivalent of 180 to 2500, and the phenol compound (D) having the nitrogen-containing group, or 2 The metal surface treatment composition according to claim 4, which is an aminated product of a modified epoxy resin obtained by reacting a secondary amino group-containing compound (F) and / or bisphenol A (E). Compound (D) is represented by the following formula (2):
(Formula 2)
(Wherein R3 is the nitrogen-containing group or hydrogen atom, at least one of R3 is the nitrogen-containing group; R4 is independently hydrogen or an alkyl group having 1 to 2 carbon atoms. The composition for metal surface treatment of Claim 5 which is an amine addition phenol compound shown by this.   The composition for metal surface treatment as described in any one of Claims 1-6 whose molar concentration of the said nitrogen-containing group is 0.1-200 times with respect to trivalent Bi ion.   The metal surface treatment method including the process of depositing a coating film on the metal material surface in the electrolytic treatment process which used the composition as described in any one of Claims 1-7 for the material as a cathode. In a metal surface treatment method for depositing a film on a metal material, including an electrolytic treatment step of performing electrolytic treatment on a metal material whose surface has been cleaned, and a water washing and baking step performed after the electrolytic treatment step,
The electrolytic treatment step is
A first step of electrolysis for 10 to 120 seconds at a voltage of 0 to 15 V, with the metal material immersed in the composition according to any one of claims 1 to 7;
The 2nd process implemented after the said 1st process electrolyzed at the voltage of 50-300V for 30-300 seconds in the state where the metal material was immersed in the composition according to any one of claims 1 to 7. Wherein the second step is carried out in the same bath subsequent to the first step or in a separate bath different from the first step.   Metal Bi and oxidized Bi formed by the method according to claim 8 or 9 are deposited as Bi in an amount of 20 to 500 mg / m 2, the total film thickness is 5 to 40 μm, and Bi on the metal material side from the center of the film thickness A metal surface treatment film characterized in that the adhesion amount (G) is a Bi adhesion distribution that is 55% or more (G / H ≧ 55%) with respect to the total Bi adhesion amount (H).