TWI493077B - A water-based metal surface treatment agent and a metal surface treatment method using the same - Google Patents

Description

Aqueous metal surface treatment agent and metal surface treatment method using same

The present invention relates to a surface treatment agent and a surface treatment method, and more particularly to an aqueous metal surface treatment agent and a metal surface treatment method using the same.

Conventionally, metal surface treatment agents used for surface treatment of metal materials mostly contain chromium components. However, the hexavalent chromium or trivalent chromium produced by them has been confirmed to cause serious pollution to the environment, and has been regulated or banned in recent years. In order to replace the chromium-containing treatment agent, a metal surface treatment agent composed of an organic vanadium compound and an inorganic acid has been proposed, but the metal material after the surface treatment of the treatment agent is 100% after the alkali-eluting fat program. The problem of white rust formation is marked by the poor corrosion resistance and alkali-resistant washing property of the protective film formed by the above treatment agent.

Therefore, it is necessary to provide an innovative and progressive aqueous metal surface treatment agent and metal surface treatment method to solve the above problems.

The present invention provides an aqueous metal surface treatment agent comprising a water-soluble zirconium compound, a bismuth compound, a fluorine-containing compound, a monophosphoric acid compound, and a metal compound. The mass ratio of the cerium compound to the water-soluble zirconium compound is between 0.5 and 2.0. The fluorine-containing compound has at least one fluorine ion group, and the content of the fluorine-containing compound is from 0.2 to 1.0 with respect to the mass ratio of the water-soluble zirconium compound. The mass ratio of the phosphoric acid compound to the water-soluble zirconium compound is between 0.2 and 0.7. The mass ratio of the metal compound to the water-soluble zirconium compound is between 0.2 and 0.6.

The invention further provides a metal surface treatment method, wherein the above-mentioned aqueous metal surface treatment agent is disposed on the surface of a metal body.

The aqueous metal surface treatment agent and the metal surface treatment method of the invention can form a protective film on the surface of the metal body, and the protection film can make the surface of the metal body have good corrosion resistance, alkali-resistant washing property, blackening resistance and The fingerprint resistance is excellent, and the aqueous metal surface treatment agent of the present invention is a chromium-free treatment agent, so that it does not pollute the environment and meets environmental protection requirements.

The aqueous metal surface treatment agent of the present invention comprises a water-soluble zirconium compound, a bismuth compound, a fluorine-containing compound, a monophosphoric acid compound, a metal compound, and optionally a water-soluble or water-dispersible organic resin. The water-soluble zirconium compound (A) may be selected from the group consisting of zirconium nitrate, zirconyl nitrate, zirconium sulfate, zirconium acetate, fluorozirconic acid, ammonium zirconium carbonate, sodium zirconium carbonate, potassium zirconium carbonate and combinations thereof. One of the groups.

The hydrazine compound (B) may be selected from the group consisting of water-dispersible fine particle cerium oxide, a decane coupling agent, and a combination thereof.

In the present embodiment, the particle size and type of the water-dispersible fine particle cerium oxide are not particularly limited. Preferably, the water-dispersible fine particle cerium oxide is colloidal cerium oxide or powdered cerium oxide, and The average particle size of the cerium oxide particles is less than 100 nm. The decane coupling agent may be selected from the group consisting of γ-aminopropyltrimethoxydecane, γ-aminopropyltriethoxydecane, γ-propylene oxide propyltrimethoxy decane, γ-propylene oxide. Propyltriethoxydecane, N-β(aminoethyl)-γ-aminopropylmethyldiethoxydecane, N-β(aminoethyl)-γ-aminopropyltrimethyl a group consisting of oxydecane, N-β(aminoethyl)-γ-aminopropyltriethoxydecane, γ-glycidylpropylmethyldiethoxydecane, and combinations thereof One of the groups, in this embodiment, the decane coupling agent will form a two-dimensional or three-dimensional Si-O-Si crosslinked structure after hydrolysis and condensation; at the same time, the Si-O bond also forms Si-OM with the metal surface. (M represents a metal) chemical bonding, which provides good adhesion between the aqueous metal surface treatment agent and the metal surface, and makes the overall structure of the formed protective film more dense.

Preferably, the content of the cerium compound (B) is from 0.5 to 2.0 in terms of the mass ratio (B/A) of the water-soluble zirconium compound (A). When the mass ratio (B/A) is less than 0.5, although a protective film is still formed on the surface of the metal material, the corrosion resistance and alkali washing resistance of the protective film are not good; when the mass ratio (B/A) is larger than At 2.0, the cost of the aqueous metal surface treatment agent is increased, but the properties of the protective film are not significantly improved, and the dryness of the film may also become poor.

The fluorine-containing compound (C) has at least one fluorine ion group. In the present embodiment, the fluorine-containing compound may be selected from the group consisting of ammonium fluorozirconium, potassium fluorozirconium, zirconium hydrofluoride, ammonium fluorocarbonate, and fluorine. One of a group consisting of titanic acid, fluoroantimonic acid, hydrofluoric acid, and ammonium hydrofluoride. Preferably, the content of the fluorine-containing compound (C) is from 0.2 to 1.0 in terms of the mass ratio (C/A) of the water-soluble zirconium compound (A). When the mass ratio (C/A) is less than 0.2, the alkali-resistant washing property of the formed protective film is not good; when the mass ratio (C/A) is more than 1.0, the blackening resistance of the protective film formed thereof is deteriorated.

The phosphoric acid compound (D) may be selected from the group consisting of condensed phosphates such as phosphoric acid, dihydrogen phosphate, monohydrogen phosphate, phosphate, tripolyphosphoric acid, tripolyphosphate, metaphosphoric acid, and 1-hydroxymethane-1. 1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxypropane-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, 2-phosphonic acid butane-1,2 And one of the group consisting of 4-tricarboxylic acid and a combination of the salts. Preferably, the content of the phosphoric acid compound (D) is from 0.2 to 0.7 in terms of the mass ratio (D/A) of the water-soluble zirconium compound (A). When the mass ratio (D/A) is less than 0.2, the adhesion between the protective film and the metal surface is affected; when the mass ratio (D/A) is more than 0.7, the metal surface is excessively activated to affect the properties of the protective film and Alkali washability.

The metal element of the metal compound (E) contains at least one of the group consisting of aluminum, magnesium, manganese and calcium. In the present embodiment, the metal compound may be selected from aluminum sulfate and aluminum nitrate. , aluminum acetate, aluminum oxide, aluminum dihydrogen phosphate, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium oxalate, magnesium oxide, manganese sulfate, manganese nitrate, manganese acetate, manganese oxide, calcium sulfate, calcium nitrate, calcium acetate, calcium oxide One of the groups formed by their combination with each other. Preferably, the content of the metal compound (E) is from 0.2 to 0.6 with respect to the mass ratio (E/A) of the water-soluble zirconium compound (A). When the mass ratio (E/A) is less than 0.2, the effect of improving the blackening resistance of the metal surface is not good; when the mass ratio (E/A) is more than 0.6, although the blackening resistance of the metal surface can be effectively improved, The corrosion resistance of the protective film is significantly deteriorated.

The water-soluble or water-dispersible organic resin (R) contains a resin which can be separately dissolved in water or dispersed in water. In the present embodiment, the water-soluble or water-dispersible organic resin may be selected from a polyurethane resin. It can be prepared by reacting a polyol such as a polyester polyol or a polyether polyol with a diisocyanate and stably dispersing or dissolving in water. Alternatively, in another embodiment, the water-soluble or water-dispersible organic resin may be selected from acrylic resin, which may be obtained by emulsion polymerization of monomers such as acrylic acid, methacrylic acid, acrylate, methacrylate, and the like. The acrylic resin may further comprise an acrylic graft epoxy resin copolymer, an acrylic graft polyurea resin copolymer, an acrylic graft polyolefin resin copolymer, or a combination thereof. The acrylic resin has an average molecular weight ranging from 10,000 to 1,000,000 and an average particle diameter of between 0.1 and 2 microns.

The water-soluble or water-dispersible organic resin may be selectively added to the aqueous metal surface treatment agent, and preferably, the ratio of the solid content of the organic resin (R) to the solid content is between 0.01 and 0.6. . When the solid content of the organic resin is less than 0.01, the formed protective film will not provide fingerprint resistance and can not further improve the blackening resistance; when the solid content of the organic resin (R) accounts for more than 0.6, the system will The doubt that the protective film is not dry enough.

Preferably, the aqueous metal surface treatment agent has a pH between 6.0 and 11.0. When the pH value is lower than 6.0, the aqueous metal surface treatment agent is unstable and precipitates easily; and when the pH is higher than 11.0, the corrosion resistance of the protective film formed by the aqueous metal surface treatment agent is not good. , it will affect the appearance of the metal surface. In addition, the aqueous metal surface treatment agent can adjust the pH value in various ways, for example, by using an acid solution or an alkali solution as needed.

The invention further provides a metal surface treatment method, wherein the above-mentioned aqueous metal surface treatment agent is disposed on the surface of a metal body. In this embodiment, the metal system may be selected from the group consisting of aluminum, zinc, galvanized steel, galvanized aluminum alloy steel, and galvanized iron alloy steel, and Before the aqueous metal surface treatment agent is disposed on the surface of the metal body, a cleaning and degreasing step may be further included to clean the surface of the metal body. In addition, in this embodiment, the metal surface treatment method further comprises a heating and drying step of the aqueous metal surface treatment agent, wherein the temperature of the heating and drying step is between 50 ° C and 250 ° C, and the aqueous metal surface The treatment agent forms a protective film on the surface of the metal body after the heating and drying step, and the thickness of the protective film is between 0.05 micrometers and 2 micrometers. Preferably, the thickness of the protective film is 0.1. Between microns and 1 micron. When the thickness of the protective film is less than 0.05 micrometer, the corrosion resistance and adhesion of the protective film are not good; when the thickness of the protective film exceeds 2 micrometers, although the corrosion resistance is improved, the surface of the metal body is caused. Poor appearance and increased production costs.

The corrosion process of the metal material is caused by the infiltration of corrosion factors (oxygen, water, chloride ions, etc.) on the metal surface, thereby inducing the electrochemical redox reaction, that is, in the cathode reaction, oxygen, water, etc. get electrons. The OH ^{- is} produced to increase the OH ^- concentration, and the anodic reaction forms metal ions due to the loss of electrons in the metal material. Therefore, in order to improve the corrosion resistance of a metal material (for example, a galvanized steel sheet), it is conceivable to suppress the oxidation-reduction reaction of the anode and the cathode.

The present invention utilizes the aqueous metal surface treatment agent to suppress the redox reaction of the anode and the cathode. Wherein, the water-soluble zirconium compound is infiltrated into the bulk structure of the ruthenium compound, and after drying by heating, the sterol bond and the zirconium ion are adsorbed (and/or crosslinked) to form a skeleton of the protective film; further, an organic resin may be added to the aqueous metal. In the surface treatment agent, once dried, an organic-inorganic composite protective film which is not easily dissolved in water is formed with the inorganic skeleton, and the barrier effect is enhanced to suppress corrosion; and the organic-inorganic composite protective film has a lower surface. Can, therefore, take into account the fingerprint resistance, to avoid the appearance of fingerprints or oil stains.

The fluorine-containing compound in the aqueous metal surface treatment agent, when the phosphoric acid compound is in contact with the metal surface, can improve the reactivity of the treatment agent with the metal surface, thereby enhancing the adhesion between the protective film/metal interface, and can obviously improve the damage of the subsequent processing. The disadvantage of protecting the film body and affecting product performance.

In addition, the metal compound in the aqueous metal surface treatment agent exists in an ionic form, and when it is in contact with the metal, it is displaced or precipitated on the surface of the metal to achieve surface modification to inhibit the blackening behavior of the metal surface; The amount of organic resin added enhances the barrier effect and can also effectively suppress black surface defects on the metal surface.

The aqueous metal surface treatment agent and the metal surface treatment method of the invention can effectively block the invasion of the corrosion factor, and at the same time, the surface of the metal material has good corrosion resistance, alkali-resistant washing resistance and blackening resistance, and the formed protective film is also With fingerprint resistance. Further, the aqueous metal surface treatment agent of the present invention is a chromium-free treatment agent, and therefore does not cause environmental pollution and meets environmental protection requirements.

The invention is illustrated in the following examples and comparative examples, but is not intended to be limited to the scope of the invention.

The common method of Embodiments 1 to 15 (hereinafter referred to as E1 to E15): 1. Aqueous metal surface treatment agent:

According to the composition type and content ratio of Table 1, the water-soluble zirconium compound, the cerium compound, the fluorine-containing compound, the phosphoric acid compound, the metal compound and the selective organic resin are respectively mixed, and then water is added and stirred uniformly to prepare separately. The aqueous metal surface treatment agent of Examples 1 to 15.

2. Surface treated metal materials:

A metal body (hot dip galvanized steel sheet, GI) was taken separately, and the surface was subjected to alkali degreasing treatment, water washing and drying, and then the above-mentioned aqueous metal surface was prepared by a #3 bar coater (RDS No. 3). The treatment agent is applied to the surface of the metal body, and the metal body coated with the aqueous metal surface treatment agent is placed in a heat cycle type oven, dried at a plate temperature of 100 ° C, and dried for a period of time, that is, separately prepared. Surface treated metal materials of Examples 1-15.

The common method of Comparative Examples 1 to 6 (hereinafter referred to as C1 to C6): 1. Aqueous metal surface treatment agent:

The preparation process was the same as that of Examples 1 to 15 except that the composition and amount of the components were changed according to Table 1. Finally, the aqueous metal surface treatment agents of Comparative Examples 1 to 6 were separately prepared.

2. Surface treated metal materials:

Except for the aqueous metal surface treatment agents of Comparative Examples 1 to 6, respectively, the other preparation processes were the same as those of Examples 1 to 15, and finally the surface-treated metal materials of Comparative Examples 1 to 6 were respectively obtained.

Table 1. Composition of aqueous metal surface treatment agents of the examples and comparative examples of the present invention

In Table 1, a1 is zirconium carbonate; a2 is zirconium oxynitrate; b1 is Snowtex C (trade name, manufactured by Nissan Chemical Co., Ltd.); b2 is Aerodisp W7520 (trade name, manufactured by Evonik); b3 is γ-epoxypropane Propyltrimethoxyoxane; c1 is fluorozirconic acid; c2 is fluorotitanic acid; d1 is dihydrogen phosphate; d2 is 1-hydroxymethane-1,1-diphosphonic acid; e1 is aluminum nitrate; and e2 is dihydrogen phosphate Aluminum; r1 is a polyurethane resin; r2 is an acrylic resin.

[test]

The steel sheets (metal materials) obtained in the above Examples 1 to 15 and Comparative Examples 1 to 6 were subjected to the following tests, and the results are shown in Table 2, respectively.

Table 2. Test results of the examples and comparative examples of the present invention

1. Corrosion resistance: The salt spray test using the standard method of JIS Z-2371 was carried out, and the area of white rust on the surface of the steel sheet was visually evaluated after 72 hours of the test, and the smaller the area where white rust occurred, the better the corrosion resistance. If the area of white rust is ≧50%, it is judged that the corrosion resistance is not good, and it is marked as “×”; if 30% ≦ white rust occurs in area ≦50%, it is judged that the corrosion resistance is poor, and it is marked as “△”; if 10% ≦ white rust When the occurrence area is ≦30%, it is judged that the corrosion resistance is acceptable, and it is marked as "○": If the white rust occurrence area is <10%, the corrosion resistance is judged to be good, and it is indicated as "◎".

2. Alkali-resistant washing property: The surface-treated steel sheet prepared above was immersed in an alkali-releasing fat agent Parclean 364S (20 g/L) manufactured by Baccarat, Japan, and adjusted to a degreasing agent aqueous solution at 65 ° C for 2 minutes. After washing, it is dried by cold air. Subsequently, the salt spray test using the standard method of JIS Z-2371 was carried out, and the area of white rust on the surface of the steel sheet was visually evaluated after 72 hours of the test. When the area where the white rust occurred was small, the alkali-resistant washing property after alkali washing was better. If the area of white rust is ≧50%, it is judged that the alkali-resistant washing property is not good, and it is marked as “×”; if the area of 5% white rust is ≦50%, it is judged that the alkali-resistant washing property is poor, and it is marked as “△”; When the area of occurrence of white rust is ≦30%, it is judged that the alkali-resistant washing property is acceptable, and it is marked as "○": If the white rust occurrence area is <10%, it is judged that the alkali-resistant washing property is good, and it is marked as "◎".

3. Blackening resistance: The steel sheets obtained in Examples 1 to 15 and Comparative Examples 1 to 6 were stacked in a stacked state under the same conditions, at a high temperature (50 ° C) and a high humidity environment (saturated humidity). After standing for 240 hours, the appearance of the steel sheet surface was visually evaluated, and the evaluation criteria were as follows:

◎: The surface appearance of the steel sheet after the test was not significantly different or darkened from the surface appearance of the untested steel sheet.

○: The surface appearance of the steel sheet after the test was slightly different or darkened than the surface appearance of the untested steel sheet.

△: The surface appearance of the steel sheet after the test was slightly different or darkened than the surface appearance of the untested steel sheet, but a small amount of precipitates adhered to the surface of the steel sheet.

×: The surface appearance of the steel sheet after the test is significantly darker than the surface appearance of the untested steel sheet, and the surface of the steel sheet has obvious precipitates attached.

4. Fingerprint resistance: The steel sheets obtained in Examples 1 to 15 and Comparative Examples 1 to 6 were coated with Vaseline for 1 hour, and then wiped clean with a toilet paper, and then the appearance of the surface of the steel sheet was visually evaluated. The evaluation criteria were as follows:

◎: The surface appearance of the steel sheet after the test was not significantly different from the surface appearance of the untested steel sheet.

○: The surface appearance of the steel sheet after the test was slightly different from the surface appearance of the untested steel sheet.

△: The surface appearance of the steel sheet after the test is slightly different from that of the untested steel sheet surface, but some micro-fingerprints are printed after touching the surface of the steel sheet.

×: The surface appearance of the steel plate after the test is significantly different from the surface appearance of the untested steel plate, and there is a clear fingerprint on the surface of the touched steel plate.

As can be seen from the results of Table 2, the steel sheets obtained in Examples 1 to 15 all have good corrosion resistance, alkali-resistant washing resistance, blackening resistance and fingerprint resistance; in contrast, the steel sheets obtained in Comparative Examples 1 to 6, It has any one or more of poor corrosion resistance, alkali wash resistance, blackening resistance and fingerprint resistance.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the scope of the present invention. The scope of the invention should be as set forth in the appended claims.

Claims (17)

An aqueous metal surface treatment agent comprising: a water-soluble zirconium compound; a bismuth compound having a mass ratio of 0.5 to 2.0 relative to the water-soluble zirconium compound; a fluorine-containing compound having At least one fluoride ion group, the content of the fluorine-containing compound is between 0.2 and 1.0 with respect to the mass ratio of the water-soluble zirconium compound; the content of the phosphoric acid compound relative to the water-soluble zirconium The mass ratio of the compound is between 0.2 and 0.6; a metal compound having a mass ratio of the metal compound to the water-soluble zirconium compound of between 0.2 and 0.6; and a water solubility or water dispersibility An organic resin containing a resin functional group which is soluble in water alone or dispersed in water, and the ratio of the solid content of the organic resin to the solid content is between 0.01 and 0.6. The aqueous metal surface treatment agent according to claim 1, wherein the water-soluble zirconium compound is selected from the group consisting of zirconium nitrate, zirconyl nitrate, zirconium sulfate, zirconium acetate, fluorozirconic acid, ammonium zirconium carbonate, sodium zirconium carbonate, and zirconium carbonate. One of a group of potassium and their combination with each other. The aqueous metal surface treatment agent of claim 1, wherein the hydrazine compound is selected from the group consisting of water-dispersible fine particle cerium oxide, decane coupling agent, and a combination thereof. The aqueous metal surface treatment agent according to claim 3, wherein the water-dispersible fine particle cerium oxide is colloidal cerium oxide or powdered cerium oxide, and The average particle size of the cerium oxide particles is less than 100 nm. The aqueous metal surface treatment agent according to claim 3, wherein the decane coupling agent is selected from the group consisting of γ-aminopropyltrimethoxydecane, γ-aminopropyltriethoxydecane, and γ-propylene oxide. Propyltrimethoxyoxane, γ-propylene oxide propyl triethoxy decane, N-β (aminoethyl)-γ-aminopropylmethyldiethoxy decane, N-β (amine Benzyl)-γ-aminopropyltrimethoxydecane, N-β(aminoethyl)-γ-aminopropyltriethoxydecane, γ-propylene oxide propylmethyldiethyl One of a group consisting of oxydecane and combinations thereof. The aqueous metal surface treatment agent according to claim 1, wherein the fluorine-containing compound is selected from the group consisting of ammonium fluorozirconium, potassium fluorozirconium, zirconium hydrofluoride, ammonium fluorotitanate, fluorotitanic acid, fluoroantimonic acid, hydrofluoric acid. And one of the group consisting of ammonium hydrofluoride. The aqueous metal surface treatment agent according to claim 1, wherein the phosphate compound is selected from the group consisting of condensed phosphoric acid such as phosphoric acid, dihydrogen phosphate, monohydrogen phosphate, phosphate, tripolyphosphoric acid, tripolyphosphate, metaphosphoric acid, and the like. Salt, 1-hydroxymethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxypropane-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, 2 - one of the group consisting of phosphonate butane-1,2,4-tricarboxylic acid and combinations of such salts. The aqueous metal surface treatment agent according to claim 1, wherein the metal element of the metal compound contains at least one of the group consisting of aluminum, magnesium, manganese and calcium. An aqueous metal surface treatment agent according to claim 8, wherein the metal compound It may be selected from the group consisting of aluminum sulfate, aluminum nitrate, aluminum acetate, aluminum oxide, aluminum dihydrogen phosphate, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium oxalate, magnesium oxide, manganese sulfate, manganese nitrate, manganese acetate, manganese oxide, One of a group consisting of calcium sulfate, calcium nitrate, calcium acetate, calcium oxide, and combinations thereof. The aqueous metal surface treatment agent according to claim 1, wherein the water-soluble or water-dispersible organic resin is selected from the group consisting of polyurethane resins, which can be prepared by reacting a polyol such as a polyester polyol or a polyether polyol with a diisocyanate. Those that are stably dispersed or dissolved in water. The aqueous metal surface treatment agent of claim 1, wherein the water-soluble or water-dispersible organic resin is selected from the group consisting of acrylic resins, which may be polymerized by emulsion polymerization of monomers such as acrylic acid, methacrylic acid, acrylate, methacrylate, and the like. In general, the acrylic resin may further comprise an acrylic graft epoxy resin copolymer, an acrylic graft polyurea resin copolymer, an acrylic graft polyolefin resin copolymer, or a combination thereof. And the acrylic resin has an average molecular weight ranging from 10,000 to 1,000,000 and an average particle diameter of between 0.1 micrometers and 2 micrometers. The aqueous metal surface treatment agent of claim 1 having a pH of between 6.0 and 11.0. A metal surface treatment method for disposing an aqueous metal surface treatment agent according to claim 1 on a surface of a metal body. The metal surface treatment method of claim 13, wherein the metal system is selected from the group consisting of aluminum, zinc, galvanized steel, galvanized aluminum alloy steel, and galvanized iron alloy steel. One. The metal surface treatment method of claim 13, further comprising subjecting the aqueous metal surface treatment agent to a heat drying step, wherein the temperature of the heat drying step is between 50 ° C and 250 ° C. The metal surface treatment method of claim 15, wherein the aqueous metal surface treatment agent forms a protective film on the surface of the metal body after the heating and drying step. The metal surface treatment method of claim 16, wherein the protective film has a thickness of between 0.05 micrometers and 2 micrometers.