KR20040058037A - Chemical conversion coating agent and surface-treated metal - Google Patents

Abstract

PURPOSE: To provide a chemical conversion coating agent containing no chromium and capable of applying good chemical conversion treatment which is equal to or more than chemical conversion treatment by zinc phosphate to all metals such as iron, zinc and aluminum. CONSTITUTION: The chemical conversion coating agent comprises at least one kind selected from the group consisting of zirconium, titanium and hafnium; fluorine; and a water-soluble epoxy compound containing an isocyanate group and/or a melamine group, wherein a content of the at least one kind selected from the group consisting of zirconium, titanium and hafnium in the chemical conversion coating agent is 20 to 10,000 ppm in terms of metal, and a content of the water-soluble epoxy compound containing the isocyanate group and/or the melamine group in the chemical conversion coating agent is 5 to 5,000 ppm as a concentration of solid matter.

Description

CHEMICAL CONVERSION COATING AGENT AND SURFACE-TREATED METAL}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a chemical conversion agent and a surface treated metal. In the case of cationic electrodeposition coating or powder coating on the surface of a metal material, chemical conversion treatment is generally performed for the purpose of improving properties such as corrosion resistance and coating adhesion. In view of further improving adhesion and corrosion resistance, the chromate treatment used for the chemical conversion treatment has recently been pointed out that the toxicity of chromium has been pointed out, and therefore, development of a chemical treatment agent containing no chromium has been required. As such a chemical conversion treatment, the treatment with zinc phosphate is widely performed (for example, see Japanese Patent Laid-Open No. 10-204649).

However, since the zinc phosphate treatment agent is a highly reactive treatment agent with high metal ion and acid concentrations, economic efficiency and workability in wastewater treatment are not good. In addition, insoluble salts are formed in the water and precipitate due to the metal surface treatment by the zinc phosphate treatment agent. Such deposits are generally called sludge, and the cost of removing and discarding such sludge is generated. And the like. In addition, in the metal surface treatment with a zinc phosphate treatment agent, it is necessary to perform surface adjustment and there is also a problem that the process becomes long.

As a metal surface treatment agent other than such a zinc phosphate chemical treatment agent or chromate chemical conversion treatment agent, the metal surface treatment agent which consists of a zirconium compound is known (for example, see Unexamined-Japanese-Patent No. 7-310189). It consists of such a zirconium compound. The metal surface treatment agent has excellent properties compared with the zinc phosphate chemical treatment agent mentioned above in that generation | occurrence | production of sludge is suppressed.

However, the chemical conversion film obtained by the metal surface treatment agent which consists of such a zirconium compound has the bad adhesiveness with the coating film obtained by various coatings, and it was normally performed as a pretreatment process of coating.

As a zirconium compound containing metal surface treatment agent which improved the problem of coating-film adhesiveness mentioned above, development of the metal surface treatment agent which consists of a zirconium compound, vanadium, and resin is also performed (for example, refer Unexamined-Japanese-Patent No. 2002-60699). However, since such a metal surface treatment agent contains vanadium, it is not preferable at the point which causes a hazard to a human body, a problem of waste liquid treatment, etc.

In addition, the metal surface treatment agent composed of such a zirconium compound is particularly difficult to form a good chemical film on the iron-based substrate due to insufficient adhesion to the iron-based substrate. Therefore, it is composed of various metal materials such as iron, zinc and aluminum. It was not possible to surface-treat the entire metal with a single treatment for automobile bodies or parts, and it was inefficient from the viewpoint of workability. Therefore, once chemical treatment was performed on an article composed of various metal materials without chromium. Development of a chemical conversion agent is desired.

SUMMARY OF THE INVENTION In view of the current state as described above, an object of the present invention is to provide a chemical conversion treatment agent capable of performing a good chemical conversion treatment equal to or higher than zinc phosphate treatment on all metals such as iron, zinc, and aluminum without containing chromium. It is one.

The present invention is at least one member selected from the group consisting of zirconium, titanium and hafnium; Fluorine; And at least one of a water-soluble epoxy compound containing an isocyanate group and a water-soluble epoxy compound containing a melamine group, wherein at least one selected from the group consisting of zirconium, titanium, and hafnium has a content of the chemical conversion agent in terms of metal. It is 20-10000 ppm, and the water-soluble epoxy compound containing the said isocyanate group and / or melamine group in the said chemical conversion treatment agent is a chemical conversion treatment agent whose content is 5-5000 ppm by solid content concentration.

The present invention is at least one member selected from the group consisting of zirconium, titanium and hafnium; Fluorine; Water-soluble epoxy compounds; And a polyisocyanate compound and a melamine resin, wherein the chemical conversion treatment agent comprises at least one selected from the group consisting of zirconium, titanium, and hafnium, and the content of the chemical conversion treatment agent is 20 to 10,000 ppm in terms of metal. The total amount of the said water-soluble epoxy compound in the said polyisocyanate compound, and / or a melamine resin is 5-5000 ppm in solid content concentration, It is related with the chemical conversion treatment agent characterized by the above-mentioned.

It is preferable that the said water-soluble epoxy compound has an amino group.

The chemical conversion treatment agent is nitrite ion; Nitro group-containing compounds; Sulfuric acid hydroxylamine; Persulfate ions; Sulfite ions; Hyposulfite ions; peroxide; Iron (III) ions; Iron citrate compounds; Bromate ions; Perchlorate ions; Chlorate ions; Chlorite ions; Or at least one chemical conversion accelerator selected from the group consisting of ascorbic acid, citric acid, tin acid, malonic acid, succinic acid and salts thereof in an amount of 1 to 5000 ppm relative to the chemical conversion treatment agent.

The chemical conversion agent may further include at least one metal ion (A), copper ion (B) and silicon-containing compound (C) selected from the group consisting of zinc ions, magnesium ions, calcium ions, aluminum ions, manganese ions and iron ions. It is preferred to further contain at least one selected from the group consisting of

It is preferable that the said silicon containing compound (C) is at least 1 sort (s) chosen from the group which consists of a silica, a water-soluble silicate compound, silicic acid esters, alkyl silicates, and a silane coupling agent.

The chemical conversion agent preferably has a pH of 1.5 to 6.5.

The present invention relates to a surface-treated metal having a chemical conversion film formed by the chemical conversion treatment agent.

It is preferable that the said chemical conversion film is 0.1-50000 mg / m <^2> as a total amount of a coating amount of the total amount of the metal contained in a chemical conversion treatment agent, and the carbon amount contained in an epoxy compound.

It is preferable that the to-be-processed object of the said surface treatment metal consists of an iron base material, a zinc base material, and / or an aluminum base material.

In the following, the present invention is described in detail.

The present invention relates to a chemical conversion treatment agent containing at least one selected from the group consisting of zirconium, titanium, and hafnium, and containing no harmful heavy metal ions such as chromium. Is treated with metal ions eluted in the chemical conversion agent to extract fluorine ions of ZrF ₆ ^2- and the zirconium hydroxide or oxide is generated by the increase of the interfacial pH and the zirconium hydroxide or oxide is precipitated on the substrate surface. I think.

In such a chemical conversion treatment agent, when an epoxy compound is contained, the epoxy compound chelates at least one selected from the group consisting of zirconium, titanium and hafnium. Accordingly, it is speculated that firm adhesion can be obtained between the epoxy compound film and the at least one film selected from the group consisting of zirconium, titanium and hafnium. Since the epoxy compound film is composed of an organic component, It is estimated that affinity with the resin component which forms the electrodeposition coating film formed above, the coating film by powder coating, etc. is strong, and can obtain adhesiveness of strength by this.

In addition, since the chemical conversion treatment agent of the present invention contains a component that acts as a curing agent, the epoxy compound film undergoes a crosslinking reaction, whereby an organic film layer having excellent physical properties and excellent adhesion and corrosion resistance can be formed. It is also.

At least one selected from the group consisting of zirconium, titanium and hafnium contained in the chemical conversion treatment agent is a chemical conversion film-forming component, and the substrate is formed by forming a chemical conversion film containing at least one selected from the group consisting of zirconium, titanium and hafnium. Corrosion resistance and abrasion resistance can be improved, and adhesion with the formed coating film can be improved.

The source of the zirconium is not particularly limited, for example, K ₂ ZrF ₆

Alkali metal fluoro zirconates; Fluoro zirconates such as (NH ₄ ) ₂ ZrF ₆ ; H ₂ ZrF _6, etc. of the fluorine-zirconate acid such as soluble fluoride zirconate and the like; Zirconium fluoride; zirconium oxide and the like.

The source of the titanium is not particularly limited, and for example, fluoro titanates such as alkali metal fluoro titanate and (NH ₄ ) ₂ TiF ₆ ; Soluble fluoro titanates such as fluoro titanate acid such as H ₂ TiF ₆ and the like; Titanium fluoride; Titanium oxide, and the like.

The source of the hafnium is not particularly limited, and for example, fluorinated hafnate acids such as H ₂ HfF ₆ ; Hafnium fluoride and the like.

As a supply source of at least one member selected from zirconium, the group consisting of titanium and hafnium, comprising at least one member selected from the group consisting of _{^{ZrF 6 2-, TiF 6 2-,}} HfF 6 2- in the film-forming ability higher ones Compound is preferred.

The content of at least one selected from the group consisting of zirconium, titanium and hafnium contained in the chemical conversion treatment agent is preferably in the range of 20 ppm lower limit and l000O ppm upper limit in terms of metal. If the lower limit is less than the lower limit, the performance of the resulting chemical film is insufficient. If the above upper limit is exceeded, further effects are not desired, so it is disadvantageous from an economic point of view. The lower limit is more preferably 50 ppm, and the upper limit is more preferably 2000 ppm.

The fluorine contained in the chemical conversion treatment agent is intended to serve as an etchant for the substrate. The source of the fluorine is not particularly limited, and examples thereof include fluorides such as hydrofluoric acid, ammonium fluoride, boric fluoride, ammonium hydrogen fluoride, sodium fluoride, sodium fluoride, and the like. Hexafluorosilicates; specific examples thereof include hydrofluoric acid silicon, zinc silicon hydrofluoric acid, manganese silicon hydrofluoric acid, magnesium hydrofluoric acid, magnesium silicon hydrofluoride, iron hydrofluoric acid, calcium hydrofluoric acid, and the like. have.

The chemical conversion treatment agent of the present invention contains a water-soluble epoxy compound. When the water-soluble epoxy compound is blended with the chemical conversion treatment agent, an epoxy skeleton is used to form a coating resin.

Since affinity improves, coating film adhesiveness becomes high and shows favorable stability

I think it's possible.

The required amount of the water-soluble epoxy compound is not particularly limited as long as it has solubility to the extent that it can be dissolved in the chemical conversion agent. The epoxy resin is preferably a skeleton. The epoxy resin is not particularly limited, for example, bisphenol A Epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, bisphenol A type propylene oxide addition type epoxy resin, bisphenol F type propylene oxide addition type epoxy resin, novolac type epoxy resin, etc. Can be mentioned. Among them, a bisphenol F type epoxy resin is preferable, and a bisphenol F type epichlorohydrin type epoxy resin is even more preferable.

It is preferable that the said water-soluble epoxy compound has an amino group.

Since the water-soluble epoxy compound which has an amino group is a cationic compound and adjusts a hydrophilicity / hydrophobicity balance, it has a property which insolubilizes and precipitates when pH of aqueous solution rises. For this reason, as the pH rises at the metal / aqueous solution interface, the epoxy compound easily precipitates on the metal surface. In the analysis result by X-ray electron spectroscopic analysis, at least one selected from the group consisting of zirconium, titanium and hafnium It was clear that the water-soluble epoxy compound which has the said amino group precipitates on the formed chemical film. The resulting chemical conversion coating is thought that to improve adhesion since it has such a structure. The amino group is not particularly restricted but includes, for example, -NH ₂ group, a monoalkylamino group, a dialkylamino group, a mono-hydroxy group, a di-hydroxyl A hydroxy amino group, the compound which has other l-tertiary amine, etc. are mentioned.

Although reaction which introduce | transduces an amino group into the epoxy resin which forms the said frame | skeleton is not specifically limited, Conventional methods, such as the method of mixing an epoxy resin and an amine compound in a solvent, are mentioned.

As an example of the water-soluble epoxy compound which has the said amino group, commercial products, such as Adeka resin EM-0436 series, Adeka resin EM-0436F series, Adeka resin EM-0718 series (all are the products of Asahi Telephone Co., Ltd.), can be used. It may be.

The water-soluble epoxy compound may have a phosphorus element. The phosphorus element is preferably included in the water-soluble epoxy compound as a phosphate ester group. The phosphate ester group may be partially alkylated. The phosphate ester group may be the epoxy group. It can introduce | transduce into an epoxy compound by reaction of a phosphoric acid compound.

The film formed by the chemical conversion treatment agent of the present invention is curable. That is, by containing a component in which a curing reaction occurs after the film is formed, the physical properties of the coating film are improved, and an organic film layer excellent in adhesion and corrosion resistance is formed. In the present invention, when the chemical conversion agent contains a water-soluble epoxy compound having an isocyanate group and / or a melamine group as the water-soluble epoxy compound, or the water-soluble epoxy compound does not contain an isocyanate group and / or a melamine group, the polyisocyanate compound and By further containing a melamine resin, sclerosis | hardenability can be provided to the obtained film. In addition, the chemical conversion treatment agent of the present invention may be one containing an isocyanate group and / or a melamine group as the water-soluble epoxy compound, and may contain a polyisocyanate compound and / or a melamine resin.

Chemical conversion treatment agent having the polyisocyanate compound and / or melamine resin

When used, the polyisocyanate compound and / or the melamine resin precipitate at the same time as the water-soluble epoxy compound is precipitated, and a curing reaction can be obtained by heating in a subsequent treatment step to obtain a cured film. It is preferable to use a block polyisocyanate compound or a half block polyisocyanate compound which is a compound having an isocyanate group and blocked with a blocking agent so as to be stably blended in an aqueous chemical conversion agent.

The block or half-block polyisocyanate compound is obtained by adding a blocking agent to the polyisocyanate compound, and the blocking agent is dissociated by heating to generate an isocyanate group. A crosslinking reaction occurs between the water-soluble epoxy compound and the isocyanate group. The film adhesion is further enhanced. The polyisocyanate compound is not particularly limited, and for example, aliphatic diisocyanates such as hexamethylene diisocyanate (including trimers), tetramethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone di Alicyclic polyisocyanate such as isocyanate, 4,4'-methylene bis (cyclohexyl isocyanate), 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylene diisocyanate Aromatic diisocyanate, such as these, etc. are mentioned.

It does not specifically limit as said blocking agent, For example, monovalent alkyl (or aromatic) alcohol, such as n-butanol, n-hexyl alcohol, 2-ethyl hexanol, lauryl alcohol, phenol carbinol, methylphenylcarbinol, etc. Ryu; Cellosoves such as ethylene glycol monohexyl ether and ethylene glycol mono 2-ethylhexyl ether; Phenols such as phenol, para-t-butylphenol and cresol; oximes such as dimethyl keto oxime, methyl ethyl keto oxime, methyl isobutyl keto oxime, methyl amyl keto oxime and cyclohexanone oxime; The lactams represented by (epsilon) -caprolactam and (gamma) -butyrolactam are mentioned. The blocking agent of oximes and lactams is more preferable from the viewpoint of resin curability because it dissociates at low temperature.

The said melamine resin is not specifically limited, For example, the alkoxy methyl melamine resin etc. which have an alkoxy group, such as a methoxy group, an ethoxy group, n-butoxy group, and i-butoxy group, etc. are mentioned. The methylol melamine resin obtained by addition reaction or addition condensation reaction of aldehydes, such as formaldehyde and palladium formaldehyde, with melamine is obtained by etherifying with a C1-C4 monohydric alcohol. In this invention, a methyl ether group is very suitable. Do.

As a specific example of the said melamine resin, it is a type (methyl ether type) which has a methoxy group, Cymel 303, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 385 (all Mitsui Cyanamid Co., Ltd.). Products), Summi M40S, Sumi M50S, Sumi M100 (all manufactured by Sumitomo Chemical Co., Ltd.), etc. Moreover, as the type having a butoxy group (butyl ether type), the milk is 20SE60, the milk is 20SE125, the milk is 20SE128. (All Mitsui Toatsu Chemical Co., Ltd.), Spabecamine G821, Spabecamine J820 (All Dainippon Ink Chemical Co., Ltd.), My Coat 506, My Coat 508 (All Mitsui Cyanamid Co., Ltd.) And the like. In addition, examples of the mixed ether melamine include Cymel 235, Cymel 238, Cymel 254, Cymel 266, Cymel 267, Cymel 285 and Cymel 1141 (all of which are Mitsui Cyanamide). Product) or Nicarac MX-40 ， Nicarac And MX-45 (all manufactured by Sanwa Chemical Co., Ltd.).

It is preferable that the chemical conversion treatment agent of this invention contains the total amount of the said water-soluble epoxy compound, a polyisocyanate compound, and / or a melamine resin in solid content concentration within the range of 5 ppm of a minimum, 5000 ppm of an upper limit. There is a possibility that proper post-coating performance may not be obtained in the coating, and if it exceeds 5000 ppm, the chemical conversion coating may not be formed efficiently. The lower limit is more preferably 30 ppm and more preferably 2000 ppm.

When the water-soluble epoxy compound which has the said isocyanate group and / or melamine group is used in the chemical conversion treatment agent of this invention, a crosslinking reaction may occur and a cured film can be formed by the isocyanate group and / or melamine group in the said water-soluble epoxy compound.

The isocyanate group can be introduced into the water-soluble epoxy compound by, for example, reacting a half-block diisocyanate compound blocked with a blocking agent with a water-soluble epoxy compound.

The half-block diisocyanate compound can be obtained by reacting the diisocyanate compound and the blocking agent at an excessive ratio of isocyanate groups. The above-mentioned compounds can be used as the blocking agent that can be used in the reaction. Synthesis | combination of a compound and reaction of a half block diisocyanate compound and a water-soluble epoxy compound are not specifically limited, It can carry out by a well-known method.

The method of introducing the melamine group into the water-soluble epoxy compound is not particularly limited. For example, a melamine resin such as Cymel 385 is added to a bisphenol A type epoxy resin or a bisphenol F type epoxy resin, and heated at 80 ° C. for 2 hours. The method of stirring is mentioned.

In the chemical conversion treatment agent of the present invention, the ratio of the functional groups of the epoxy compound and the isocyanate group and / or the melamine group which cause the curing reaction are kept constant, so that the water-soluble epoxy compound and the polyisocyanate compound and / or the melamine resin are used together. It is more preferable to use the water-soluble epoxy compound which has the said isocyanate group and / or a melamine group independently rather than using.

It is preferable that the chemical conversion treatment agent of this invention contains the said water-soluble epoxy compound which has the said isocyanate group and / or melamine group in solid content concentration within the range of 5 ppm of minimum, 5000 ppm. In the chemical conversion film obtained when it is less than 5 ppm, There is a possibility that proper post-coating performance may not be obtained, and if it exceeds 5000 ppm, there is a possibility that a chemical conversion film may not be formed efficiently. The lower limit is more preferably 30 ppm, and the upper limit is more preferably 2000 ppm.

It is preferable that the chemical conversion treatment agent of this invention also contains a chemical conversion accelerator. The said chemical conversion accelerator has the effect of suppressing the stain | stain on the surface of the chemical conversion film obtained by the metal surface treatment agent of a zirconium compound. The occurrence of the same stain occurs because the amount of deposited film is different due to the difference between the edge portion and the flat portion of the substrate. For example, when treating a metal substrate having an edge portion with a surface treatment agent made of a conventional zirconium compound, the cathode dissolution reaction selectively occurs at the edge portion, so that a cathode reaction is likely to occur, and as a result, a film is deposited near the edge portion. On the other hand, such staining occurs because the anode dissolution reaction hardly occurs in the planar portion and the deposition of the film is suppressed.

According to the zinc phosphate chemical treatment, since the obtained chemical film is a thick film (thick film) type, staining is not a big problem, but since the chemical film made of a zirconium compound is a thin film type, a sufficient coating amount in the flat part which is difficult to chemically treat If it cannot be obtained, it may cause uneven coating, and may cause problems in appearance, corrosion resistance, and the like.

In the present invention, the chemical reaction accelerator is blended with the chemical treatment agent so that the chemical conversion treatment can be performed without causing a difference in chemical conversion treatment between the edge portion and the flat portion.

The chemical reaction accelerator may include nitrite ions; Nitro group-containing compounds; Sulfuric acid hydroxylamine; Persulfate ions; Sulfite ions; Hyposulfite ions; peroxide; Iron (III) ions; Iron citrate compounds; Bromate ions; Perchlorate ions; Chlorate ions; Chlorite ions; Or at least one selected from the group consisting of ascorbic acid, citric acid, tartaric acid, malonic acid, succinic acid and salts thereof, and among them, one having an oxidizing action or an organic acid to efficiently promote the etching reaction is preferable.

By incorporating such a chemical reaction promoter into a chemical conversion treatment agent, it is possible to adjust the bias of the film deposition and to obtain a good chemical film without spots even at the edge portion and the flat portion of the substrate.

The source of the nitrite ion is not particularly limited, and examples thereof include sodium nitrite, potassium nitrite, ammonium nitrite, and the like. The nitro group-containing compound is not particularly limited. For example, nitrobenzene sulfonic acid and nitro guanidine. The source of the persulfate ions is not particularly limited, and examples thereof include Na ₂ S ₂ O ₈ , K ₂ S ₂ O ₈ , and the like. The source of the sulfite ions is not particularly limited. Examples thereof include sodium sulfite, potassium sulfite, ammonium sulfite, and the like. The source of the sulfite ions is not particularly limited. The peroxide is not particularly limited, and examples thereof include hydrogen peroxide, sodium peroxide and potassium peroxide.

The source of the iron (III) ions is not particularly limited, and examples thereof include ferric nitrate, ferric sulfate, ferric chloride, and the like. The ferric citrate compound is not particularly limited. And ammonium ferric citrate, sodium ferric citrate, potassium ferric citrate, and the like. The source of the bromide ion is not particularly limited, and examples thereof include sodium bromide, potassium bromide, and ammonium bromide. The source of the perchlorate ion is not particularly limited, and examples thereof include sodium perchlorate, potassium perchlorate, ammonium perchlorate and the like.

The source of the chlorate ions is not particularly limited, and for example, sodium chlorate, potassium chlorate, ammonium chlorate, and the like. The source of the chlorite ions is not particularly limited, and for example, sodium chlorite, nitrite Potassium chlorate, ammonium chlorite, and the like. Ascorbic acid and salts thereof are not particularly limited, and examples thereof include ascorbic acid, sodium ascorbate, potassium ascorbate and ammonium ascorbate. have. The citric acid and salts thereof are not particularly limited, and examples thereof include citric acid, sodium citrate, potassium citrate, and ammonium citrate. The said tartaric acid and its salt are not specifically limited, For example, a tartaric acid, ammonium titanate, potassium titanate, sodium titanate, etc. are mentioned. The said malonic acid and its salt are not specifically limited, For example, malonic acid, ammonium malonate, potassium malonate, sodium malonate, etc. are mentioned. The succinic acid and salts thereof are not particularly limited, and examples thereof include amber acid, sodium amber acid, potassium amber acid, ammonium amber acid and the like.

Although the above-mentioned chemical reaction accelerator may be used alone, two or more components may be used as needed.

In the chemical conversion treatment agent of the present invention, the compounding amount of the chemical reaction accelerator is preferably in the range of 1 ppm lower limit and 5000 ppm upper limit. If it is less than 1 ppm, sufficient effect cannot be obtained. The lower limit is preferably 3 ppm and more preferably 5 ppm. The upper limit is preferably 2000 ppm and more preferably 1500 ppm.

The chemical conversion treatment agent of the present invention is also composed of at least one selected from the group consisting of zinc ions, magnesium ions, calcium ions, aluminum ions, manganese ions and iron ions (A), copper ions (B) and silicon-containing compounds (C). It is preferable to contain at least 1 sort (s) selected from the group. By containing such a component, coating film adhesiveness can be improved further.

The content of at least one metal ion (A) selected from the group consisting of zinc ions, magnesium ions, calcium ions, aluminum ions, manganese ions and iron ions is preferably in the range of 1 ppm lower limit and 5000 ppm upper limit. If it is less than l ppm, the corrosion resistance of the obtained chemical conversion film is deteriorated, and it is not preferable. If it exceeds 5000 ppm, since the effect increase does not appear, it is disadvantageous from an economic viewpoint, and there exists a possibility that adhesiveness may fall after coating. The said minimum is 20 ppm. More preferably, 2000 ppm is more preferable for the said upper limit.

It is preferable that content of said copper ion (B) exists in the range of a minimum of 0.5 ppm and an upper limit of 100 ppm. If it is less than 0.5 ppm, the corrosion resistance of the obtained chemical film falls, and it is unpreferable. When it exceeds 100 ppm, there exists a possibility that it may cause a side effect with respect to a zinc base material and an aluminum base material. The said minimum is more preferable 2 ppm, and the said upper limit 50 ppm is more preferable. The said copper ion has a high effect which stabilizes a chemical film by substitution plating on the surface of a metal base material, and stabilizes the rust which arises on the surface of a metal base material, and is a small effect compared with other components. Is estimated to be obtained.

The source of each of the components (A) and (B) is not particularly limited, and can be blended into the chemical conversion agent as, for example, nitric oxide, sulfur oxide, or fluoride. Among these, nitric oxide does not adversely affect the chemical reaction. Therefore, it is preferable.

The said silicon-containing compound (C) is not specifically limited, For example, water-soluble silicate compounds, such as silica, sodium silicate, potassium silicate, lithium silicate, such as water-dispersible silica, alkyl silicates, such as silicate ester, diethyl silicate, etc. And silane coupling agents. Among them, silica is preferable as the effect of improving the barrier property of the chemical conversion film, and water dispersible silica is more preferable as the dispersibility in the chemical conversion agent. The water-dispersible silica is not particularly limited, and examples thereof include spherical silica, chain silica, and aluminum-modified silica with less impurities such as sodium. The spherical silica is not particularly limited. For example, "Snotex N", "Snotex O", "Snotex OXS", "Snotex UP", "Snotex XS" Colloidal silica or aerosols (such as `` Snotex AK '', `` Snotex OUP '', `` Snotex C '', and `` Snotex OL '' (all manufactured by Nissan Chemical Industries) Fumed silica, such as these, etc. are mentioned. The said chain silica is not specifically limited, For example, silica sol, such as "Snotex PS-M", "Snotex PS-M0", "Snotex PS-SO" (all of which are manufactured by Nissan Chemical), etc. are mentioned. Can be. Examples of the aluminum-modified silica include commercially available silica sol such as "Adelite AT-20A" (Asahi Telephone Co., Ltd.).

It is preferable that the content of the silicon-containing compound (C) is in the range of 1 ppm lower limit and 5000 ppm upper limit as the silicon component. If it is less than 1 ppm, the corrosion resistance of the obtained chemical film is lowered, which is undesirable. There is no increase in the above effect, so it is economically disadvantageous and there is a possibility that the adhesion after coating is lowered. The lower limit is more preferably 5 ppm, and the upper limit is more preferably 2000 ppm.

As the silicon-containing compound (C), it is also possible to use a silane coupling agent and a hydrolyzate thereof. Although the silane coupling agent is not particularly limited, for example, an amino group-containing silane coupling agent is suitably used. By blending the amino group-containing silane coupling agent with the chemical conversion agent, the curing reaction at the interface between the chemical conversion film and the electrodeposition coating, powder coating, etc. is promoted, and the adhesion between the two is improved. As the amino group-containing silane coupling agent, It will not specifically limit, if it has at least 1 amino group in a molecule | numerator, and has a siloxane bond.

The amino-containing silane coupling agent is not particularly limited, for example, N-2

(Aminoethyl) 3-aminopropylmethyl dimethoxysilane, N-2 (aminoethyl) 3-aminopropyl trimethoxysilane, N-2 (aminoethyl) 3-aminopropyl triethoxysilane, 3-aminopropyl tri Methoxysilane, 3-aminopropyl triethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N- (vinylbenzyl) -2-aminoethyl-3-amino Propyl trimethoxysilane, N, N-bis [3- (trimethoxysilyl) propyl] ethylenediamine, etc. are mentioned.

The silane coupling agent may be a hydrolyzate thereof. The hydrolyzate of the silane coupling agent may be a conventionally known method, for example, dissolving the silane coupling agent in ion-exchanged water and adjusting it to an acid using any acid. It can manufacture by a method etc.

Each component of the above (A) to (C) may be used alone or in combination of two or more components as necessary. When two or more components are used simultaneously, the content of each component is within the above range. It is preferable that the total amount of each component is not specifically limited.

Particularly preferred combinations include at least one metal ion (A), copper ion (B), silicon-containing compound (C) and copper selected from the group consisting of zinc ions, magnesium ions, calcium ions, aluminum ions, manganese ions and iron ions. And combinations of ions (B).

It is preferable that pH of the chemical conversion treatment agent of this invention is adjusted in the range of the lower limit 1.5 and the upper limit 6.5. If the pH is less than l.5, the water-soluble epoxy compound is less likely to be precipitated, so the coating film adhesion may not be sufficiently improved. When the pH exceeds 6.5, the chemical conversion treatment may not proceed sufficiently. The lower limit is more preferably 2.0, and the upper limit is more preferably 5.5. The lower limit is more preferably 2.5, and the upper limit is 5.0 is more preferable. The chemical conversion treatment agent of the present invention may contain complex fluoride ions, nitrates, sulfates, fluoride salts and the like as described above, and therefore it is preferable to add an alkali component to adjust the pH within the above range. The alkali component which can be used for adjusting pH is not specifically limited, Sodium hydroxide, potassium hydroxide, ammonia, an amine compound, etc. are mentioned.

It is more preferable that the chemical conversion treatment agent of the present invention is substantially free of phosphate ions. The fact that the chemical conversion treatment agent is substantially free of phosphate ions means that the phosphate ions are not contained as a function of the components in the chemical conversion treatment agent. If I do not substantially contain phosphate ions, it is possible to suppress the occurrence of sludge such as iron phosphate and zinc phosphate that occur when zinc phosphate treatment agent is used without substantially using phosphorus which causes environmental burden. Furthermore, the burden on the environment by phosphorus is eliminated and it is a great advantage in terms of waste water workability.

The treatment method of the metal surface by the chemical conversion treatment agent of this invention is not specifically limited, It can carry out by making the said chemical conversion treatment agent contact a metal surface. The treatment method is not specifically limited, For example, an immersion method, a spray method, and a roll And-coat method.

In the treatment method described above, it is preferable to adjust the temperature of the treatment liquid within the lower limit of 20 ° C and the upper limit of 70 ° C. By carrying out the reaction within such a temperature range, the chemical conversion treatment reaction can be efficiently performed. The lower limit is more preferably 30 ° C., and the upper limit is more preferably 50 ° C. Although the treatment time varies depending on the concentration of the chemical treatment agent and the treatment temperature, the lower limit is preferably 20 to 300 seconds.

In the said processing method, it is preferable to perform the degreasing treatment, the degreasing washing | cleaning process before a chemical conversion treatment by the said chemical conversion treatment agent, and performing a chemical conversion washing | cleaning process after a chemical conversion treatment.

The degreasing treatment is carried out to remove oil or contamination adhering to the surface of the substrate. The degreasing treatment is usually performed for 30 minutes at a temperature of 30 to 55 ° C. using a degreasing agent such as an unattended and nitrogen-free degreasing washing liquid. Therefore, the preliminary degreasing treatment can be performed before the degreasing treatment.

The degreasing washing treatment after degreasing is performed by spraying one or more times using a large amount of washing water to wash the degreasing agent after the degreasing treatment.

The above-described water washing treatment is performed one or more times so as not to adversely affect the adhesion, corrosion resistance, and the like after the various coatings thereafter. In this case, the final water washing is appropriately performed with pure water. In either, spray washing or immersion washing may be performed, and washing may be performed by combining these methods.

In the chemical conversion treatment using the chemical conversion treatment agent of the present invention, surface adjustment treatment is performed.

It is also excellent in workability because it does not have to.

In the chemical conversion treatment using the chemical conversion treatment agent of the present invention, a drying step is not necessarily required after performing the water washing treatment after the chemical conversion. Even if the coating is performed in a state where the chemical conversion film is wet (wet) without performing the drying step, the obtained performance is not affected. In addition, when performing a drying process, it is preferable to perform cold air drying, hot air drying, etc. In the case of performing hot air drying, 300 degrees C or less is preferable also in order to prevent decomposition | disassembly of organic matter.

Examples of the metal substrate to be treated by the chemical conversion treatment agent of the present invention include iron-based substrates, aluminum-based substrates, and zinc-based substrates. Iron, aluminum, and zinc-based substrates include iron-based substrates made of iron and / or alloys thereof. An aluminum substrate made of aluminum and / or an alloy thereof, and a zinc based substrate made of zinc and / or an alloy thereof. The chemical conversion treatment agent of the present invention includes a plurality of metal substrates of an iron base, an aluminum base, and a zinc base. It can also be used for chemical conversion of the finished coating.

The chemical conversion treatment agent of the present invention is preferable in that it is possible to form a good coating film even for an iron-based base material which is difficult to obtain sufficient coating film adhesion in a chemical conversion treatment agent made of ordinary zirconium or the like. It is excellent in the point that it can also be used for the processing of the to-be-processed object to contain. The surface-treated metal which has a chemical conversion film formed by the chemical conversion treatment agent of this invention is also one of this invention.

The iron-based substrate is not particularly limited, and examples thereof include a cold rolled steel sheet and a hot rolled steel sheet. The aluminum base is not particularly limited, and examples thereof include a 5000 series aluminum alloy and a 6000 series aluminum alloy. The zinc-based substrate is not particularly limited, for example, zinc-plated steel sheet, zinc-nickel plated steel sheet, zinc-iron plated steel sheet, zinc-chromium-plated steel sheet, zinc-aluminum-plated steel sheet, zinc-titanium plated steel sheet, zinc- Zinc- or zinc-based alloy-coated steel sheets such as zinc-based electroplating such as magnesium-plated steel sheets and zinc-manganese-plated steel sheets, hot dip galvanizing and deposition-coated steel sheets, and the like. The substrate can be chemically treated simultaneously.

The chemical conversion film obtainable by the chemical conversion treatment agent of the present invention has a lower limit O.l as the total amount of metal content in the chemical conversion agent and the total amount of carbon contained in the epoxy compound. mg / m²， Up to 5OO mg / m²It is preferable to be in the range of 0.1 mg / m.²If it is less than a uniform chemical film, it is not preferable.²If it exceeds, it is economically disadvantageous. The lower limit is 5 mg / m.²More preferably, the upper limit is 200 mg / m²Is more preferable.

The coating method which can be performed with respect to the metal base material which has a chemical conversion film formed by the chemical conversion treatment agent of this invention is not specifically limited, Conventionally well-known coating methods, such as cation electrodeposition coating and powder coating, can be performed. Since the chemical conversion treatment agent of this invention can perform favorable treatment with respect to all metals, such as iron, zinc, and aluminum, it can be used suitably as a pretreatment of the cation electrodeposition coating of the to-be-processed object at least one part which consists of an iron base material. The said cationic electrodeposition coating is not specifically limited, The conventionally well-known cation electrodeposition paint which consists of an amino-ized epoxy resin, an amino-acrylic resin, a sulfonated epoxy resin, etc. can be apply | coated.

The chemical conversion treatment agent of the present invention is a chemical conversion treatment agent containing at least one selected from the group consisting of zirconium, titanium and hafnium as a film forming component. Since the chemical conversion film formed by the chemical conversion treatment agent of the present invention has good adhesion to the coating film, In order to improve the adhesion between the film and the coating film, it can be used as a pretreatment on the surface of the metal. Furthermore, the chemical conversion treatment agent of the present invention provides a good chemical coating film even for an iron-based substrate, which has not been able to obtain sufficient adhesiveness with a conventional chemical conversion treatment agent made of zirconium or the like. It can be formed, and the whole metal can be surface-treated by one process with respect to the to-be-painted object which consists of various metal materials, such as iron, zinc, and aluminum.

Example

In the following Examples, the present invention will be described in more detail, but the present invention is not limited only to these examples. In addition, "parts" means "parts by weight" and "%" unless otherwise specified. It also means "% by weight" unless there is a special objection.

Preparation Example 1 (Manufacturing Method of Amino Group-Containing Water-Soluble Epoxy Compound A)

30 parts of diethanol amine and 110 parts of cellosolve acetate were added to 190 parts by weight of a bisphenol F-type epichlorohydrin type epoxy compound having an epoxy equivalent of 190, and reacted at 100 ° C for 2 hours for an amino group-containing water-soluble epoxy compound having a nonvolatile content of 70% by weight. A) was obtained.

Preparation Example 2 (Manufacturing Method of Amino Group-Containing Water-Soluble Epoxy Compound B Having a Phosphorus Element)

38 parts of monoethyl phosphate was mix | blended with 190 weight part of bisphenol F-type epichlorohydrin type epoxy compounds of epoxy equivalent 190, and it stirred at 130 degreeC for 3 hours, and obtained the epoxy resin which has a phosphorus element. Furthermore, 30 parts of diethanolamine and 110 parts of cellosolves were added, and it was made to react at 100 degreeC for 2 hours, and the amino group containing water-soluble epoxy compound (B) which has the phosphorus element of 70 weight% of non volatile matters was obtained.

Preparation Example 3 (Manufacturing Method of Amino Group-Containing Water-Soluble Epoxy Compound C Having an Isocyanate Group)

100 parts of 2,4-toluene diisocyanate precopolymer (trade name: Colonate L, manufactured by Nippon Polyurethane Co., Ltd.) of trimethylolpropane with a NCO 13.3 wt% and a nonvolatile content 75 wt%, 44 parts nonylphenol, and 5 dimethylbenzylamine 5 Part and 65 parts of cellosolve acetate were mixed and stirred at 80 ° C. for 3 hours under nitrogen to obtain a partially blocked polyisocyanate having a nonvolatile content of 70% by weight and 20% by weight of NCO.

70 parts of the amino group-containing water-soluble epoxy compound (A) prepared in Preparation Example 1 and 30 parts of the partially blocked polyisocyanate were mixed and stirred at 80 ° C. for 4 hours, whereby absorption of the NCO group was completely eliminated by infrared spectroscopy. Thereafter, 3 parts of acetic acid was mixed and diluted with ion-exchanged water to obtain an amino group-containing water-soluble epoxy compound (C) having an isocyanate group having a nonvolatile content of 25% by weight and a pH of 4.1.

Preparation Example 4 (Method for Producing Amino Group-Containing Water-Soluble Epoxy Compound D Having a Phosphorus Element and an Isocyanate Group)

In the same manner as in Preparation Example 3, except that the amino group-containing water-soluble epoxy compound (B) having the phosphorus element prepared in Preparation Example 2 was used instead of the amino group-containing water-soluble epoxy compound (A) prepared in Preparation Example 1. The amino group containing water-soluble epoxy compound (D) which has a phosphorus element and an isocyanate group was obtained.

Production Example 5 (Manufacturing Method of Amino Group-Containing Water-Soluble Epoxy Compound E Having Phosphorus and Isocyanate Groups)

Instead of the bisphenol F-type epichlorohydrin-type epoxy resin of epoxy equivalent 190, the epoxy equivalent of 500 bisphenol-A epichlorohydrin-type epoxy compound was used, and 30 parts of diethanolamine and cellosolve acetate ll0 part at the time of amine addition. An amino group-containing water-soluble epoxy compound (E) having a phosphorus element and an isocyanate group was obtained in the same manner as in Production Example 4, except that 65 parts of N-methylethanolamine and 245 parts of cellosolve acetate were used instead.

Production Example 6 (Manufacturing Method of Amino Group-Containing Water-Soluble Epoxy Compound G Having an Isocyanate Group)

An amino group-containing water-soluble epoxy compound (F) was produced in the same manner as in Production Example 2, except that the epoxy equivalent 190 bisphenol A epichlorohydrin-type epoxy compound was used instead of the epoxy equivalent 190 bisphenol F-type epichlorohydrin-type epoxy resin. ) Into another reactor, 174 parts of 2,4-toluene diisocyanate, 96 parts of phenol, 5 parts of dimethylbenzyl amine, 118 parts of ethyl acetate were added and reacted with stirring at 80 ° C. under nitrogen atmosphere for 3 hours, 70% by weight of nonvolatile content, NCO 10.6 Weight% partially blocked isocyanates were obtained. 30 parts of this partially blocked isocyanate and 70 parts of amino group-containing water-soluble epoxy compound (F) were reacted at 80 ° C. for 4 hours with stirring. After confirming that absorption of NCO was completely eliminated by infrared spectroscopy, 3 parts of acetic acid were added and ion exchange was performed. Dilution with water gave an amino group-containing water-soluble epoxy compound (G) having a nonvolatile content of 25% by weight and pH 4.1.

Examples 1-16 and Comparative Examples 5-15

Commercially available cold rolled steel sheets (SPCC-SD, Japan Test Panel, 70mm × 150mm × 0.8mm), Zinc-plated steel sheets (GA steel plate, Japan Test Panel, 70mm × l50mm × 0.8mm), 5000 aluminum (Japan test) The coating pretreatment was performed on the following conditions based on the panel company, 70 mm x 150 mm x 0.8 mm), or 6000 type aluminum (Japanese test panel company, 70 mm x 150 mm x 0.8 mm).

(1) painting pretreatment

Degreasing treatment: It was immersed for 2 minutes at 40 degreeC with 2 weight% "Surf Cleaner EC92" (Nippon Paint Co., Ltd. degreaser).

Washing treatment after degreasing: Sprayed with tap water for 30 seconds.

Chemical conversion treatment: Chemical conversion treatment was performed by preparing a chemical conversion treatment agent having the composition shown in Tables 1 and 2, and immersing the metal substrate in the chemical conversion treatment agent under the conditions shown in Tables 1 and 2. In addition, nitric acid and sodium hydroxide were used for adjustment of pH.

Water-washing treatment after chemical conversion: It was sprayed for 30 seconds with tap water. Again, it was sprayed for 30 seconds with ion-exchanged water. After water washing, electrodeposition coating was performed as it is without drying the metal base material. In addition, the chemical conversion films obtained in Examples 14, 16 and Comparative Example 14 were subjected to electrodeposition coating after cold-air drying.

(2) painting

After treating a 1 m ² metal substrate per 1 L of chemical conversion treatment agent, electrodeposition coating was carried out using a `` Powernics 110 '' (Nippon Paint Co., Ltd., cationic electrodeposition paint) so as to have a dry film thickness of 20 µm, followed by washing for 20 minutes at 170 ° C. after washing with water. After baking, a trial plate was produced.

Comparative Examples 1 to 4

After degreasing and washing with water, surface adjustment was performed for 30 seconds at room temperature using Surf Fine 5N-8M (Nippon Paint Co., Ltd.) and at 35 ° C using Surf Dyne SD-6350 (Nippon Paint Co., Ltd., zinc phosphate chemical treatment agent). A test plate was obtained in the same manner as in Example 1 except that the immersion treatment was performed for 2 minutes and chemical conversion treatment was performed. The pH and treatment conditions of the chemical conversion treatment agent are shown in Table 2.

Examples 17-20

As a polyisocyanate compound, Duranate E402 (Asahi Kasei Kogyo Co., Ltd.), and a melamine resin, Cymel 385 (Mitsui Cyanamide Co., Ltd.) were prepared, and a chemical conversion treatment agent having the composition shown in Table 3 was prepared, and was the same as in Example 1. The test plate was produced.

TABLE l

Note 1) The source of Zr was H ₂ ZrF ₆ and the source of Ti was H ₂ TiF ₅ .

Note 2) Zr, Ti, and other metal ion concentrations are concentrations as metal components.

Note 3) Epoxy compound concentration is expressed as solid content concentration. Epoxy compound H; Dinercast EM-101 (Nagase Industries, Water Disperse Epoxy Resin Emulsifying Epivis Epoxy Resin)

Note 4) The concentration of SiO ₂ or Na silicate is indicated as the concentration of Si component.

Si compound A; KBP-90 (Shin-Etsu Silicone Co., Ltd.).

Si compound B; γ-aminopropyl triethoxysilane (Shin-Etsu Silicone Co., Ltd.).

Si compound C; After adding acetic acid to Si compound B and adjusting to pH 4, it hydrolyzed at room temperature for 3 days.

Si compound D; γ-glycidoxypropyl triethoxysilane (Shin-Etsu Silicone Co., Ltd.).

Note 5) The processed materials are as follows.

SPC; Cold rolled steel sheet; SPCC-SD (Japan Test Panel)

GA; Galvanized Steel Sheet (Japan Test Panel)

5000 Al; 5000 series aluminum (Japan test panel company)

6000 Al; 6000 series aluminum (Japan test panel company)

NOTE 6 Each metal used nitrate.

TABLE 2

TABLE 3

Evaluation test

(Capacity)

The coating amount was represented by the total amount of the metal contained in the chemical conversion treatment agent and the carbon amount contained in the epoxy compound in the obtained film. The total amount of the metal was analyzed using "XRF1700" (Shimadzu Corporation, Fluorescence X-ray Analyzer). And the amount of carbon in the epoxy compound was analyzed using "RC412" (LECO's moisture analyzer).

(Appearance of the bath)

After treating the lm ² metal substrate per liter of the chemical conversion treatment agent, the haze in the chemical conversion treatment agent was visually observed. Table 4 shows the evaluation results.

: Not cloudy

×: turbidity

(Second Adhesion Test (SDT))

In the obtained test plate, two longitudinal parallel cuts reaching the bottom were put, and then immersed in a 5% NaCl aqueous solution at 50 ° C. for 480 hours. Then, the cut part was peeled off by tape and the peeling of paint was observed.

◎: no peeling

: Slightly peeled off

X: Peeling width 3 mm or more

The evaluation results are shown in Table 4.

Compound Cycle Corrosion Test (CCT)

In Examples and Comparative Examples, after a test plate obtained by electrodeposition was damaged by a cutter knife, the first wet process (2 hours, 40 ℃, 95% humidity), salt spray (2 hours, 5% aqueous NaCl solution, 35 ℃), the first drying process (2 hours, 60 ℃), the second wet process (6 hours, 50 ℃, humidity 95%), the second drying process (2 hours, 60 ℃), the third wet process (6 hours After 50 cycles consisting of 50 ° C. and 95% humidity, the maximum expansion width of both sides of the cut portion was measured. The evaluation criteria are as follows.

◎: 0 to 3.5 mm or less

: Less than 3.6-7 mm

×: 7 mm or more

The evaluation results are shown in Table 4.

TABLE 4

From Table 4, sludge does not appear in the chemical conversion treatment agent of the present invention, and the chemical conversion coating film obtained by the chemical conversion treatment agent of the present invention has good coating film adhesion even on an iron-based substrate. On the other hand, the chemical conversion treatment agent prepared as a comparative example The obtained chemical film was not able to obtain good results in all items.

The chemical conversion treatment agent of the present invention does not require the use of heavy metals such as chromium, and the chemical conversion treatment using the chemical conversion treatment agent of the present invention forms a good chemical coating film without surface adjustment. The chemical conversion treatment agent of the present invention is also preferable. Furthermore, since the chemical conversion treatment agent of the present invention can provide sufficient coating film adhesion to the iron-based substrate, it is possible to perform treatment on the object to be treated containing at least a portion of the iron-based substrate.

Claims (12)

(i) at least one member selected from the group consisting of zirconium, titanium and hafnium; (ii) fluorine; And (iii) a water-soluble epoxy compound containing at least one of an isocyanate group and a melamine group, At least one selected from the group consisting of (i) zirconium, titanium and hafnium is 20-10000 ppm in terms of metal in the chemical conversion treatment agent, and (ii) a water-soluble containing at least one of the isocyanate group and melamine group. Epoxy compound is a chemical conversion treatment, characterized in that its content is 5 to 5000 ppm in solid content concentration. (i) at least one member selected from the group consisting of zirconium, titanium and hafnium; (ii) fluorine; (iii) a water soluble epoxy compound; And (iv) at least one of a polyisocyanate compound and a melamine resin, At least one selected from the group consisting of (i) zirconium, titanium and hafnium has a content in the conversion treatment agent of 20 to 10000 ppm in terms of metal, and (iii) the water-soluble epoxy compound in the conversion treatment agent and the (iv) poly The total amount of the isocyanate compound and the melamine resin is 5 to 5000 ppm in solid content concentration. The method according to claim 1 or 2, The water-soluble epoxy compound contains an amino group, The chemical conversion treatment agent characterized by the above-mentioned. The method according to claim 1 or 2, Nitrite ions; Nitro group-containing compounds; Sulfuric acid hydroxylamine; Persulfate ions; Sulfite ions; Hyposulfite ions; peroxide; Iron (III) ions; Iron citrate compounds; Bromate ions; Perchlorate ions; Chlorate ions; Chlorite ions; Or 1 to 5000 ppm of at least one chemical conversion accelerator selected from the group consisting of ascorbic acid, citric acid, tin acid, malonic acid, succinic acid and salts thereof. The method according to claim 1 or 2, At least one selected from the group consisting of at least one metal ion (A), copper ion (B) and silicon-containing compound (C) selected from the group consisting of zinc ions, magnesium ions, calcium ions, aluminum ions, manganese ions and iron ions The chemical conversion treatment agent further contains 1 type. The method according to claim 5, The silicon-containing compound (C) is at least one member selected from the group consisting of silica, water-soluble silicate compounds, silicate esters, alkyl silicates, and silane coupling agents. The method according to claim 1 or 2, The chemical conversion agent of which pH is 1.5-6.5. It has a chemical conversion film formed by the chemical conversion treatment agent of Claim 1 or 2, The surface treatment metal characterized by the above-mentioned. The method according to claim 8, The chemical conversion coating is a total amount of the total amount of the metal contained in the chemical conversion treatment agent and the amount of carbon contained in the epoxy compound, and the surface-treated metal, characterized in that: Ol-50000 mg / m ² . The method according to claim 8, The workpiece is a surface-treated metal, characterized in that it is composed of an iron-based substrate, a zinc-based substrate, and / or an aluminum-based substrate. The method according to claim 1 or 2, Wherein said water-soluble epoxy compound contains phosphorus. The method according to claim 2, A chemical conversion treatment agent, wherein the water-soluble epoxy compound contains an isocyanate group and / or a melamine group.