JPH08170179A - Resin chromating bath and surface treated steel sheet - Google Patents

Abstract

PURPOSE: To impart excellent corrosion resistance, paint adhesion and resistances to Cr elution, scratching and fingerprinting by surface.,treating a cold-rolled steel sheet, a galvanized steel sheet, etc., with a resin chromating soln. of specified composition. CONSTITUTION: An org. resin is obtained by subjecting at least methacrylic acid and acrylic acid as the essential components among the monomers selected from a group consisting of methyl methacrylate, butyl methacrylate, glycidyl methacrylate, methacrylic acid, acrylic acid, a monomer contg. a phosphate group and hydroxyethyl methacrylate to a reaction. The treating bath consists of an aq. soln. formed by mixing 100 pts.wt.of the org. resin, 5-50 pts.wt. of chromic acid and 10-60 pts.wt. of phosphoric acid. When the cold-rolled steel sheet and galvanized steel sheet are chromated with the resin chromating bath, the film is preferably formed at 10-300mg/m<2> , expressed in terms of Cr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a resin chromate treatment bath and a resin chromate film for forming a resin chromate film by coating the surface of a metal, for example, a cold rolled steel plate, a Zn plated steel plate, a Zn-based alloy plated steel plate, etc. and drying it. The present invention relates to a surface-treated steel sheet having

[0002]

2. Description of the Related Art Cold rolled steel sheets, Zn plated steel sheets, for example Zn
-Ni system, Zn-Ni-Co system, Zn-Ni-Cr system,
Zn-Fe system, Zn-Co system, Zn-Cr system, Zn-M
In order to improve the corrosion resistance of an n-based Zn-based alloy plated steel sheet or the like, a chromate treatment is generally performed to form a chromate film. This chromate treatment can be roughly classified into electrolytic chromate and coating chromate. As the electrochromic chromate, for example, chromic acid as a main component and sulfuric acid added thereto (Japanese Patent Publication No. 39-39).
7461), with phosphoric acid added (Japanese Patent Publication Sho 30)
No. 3514, Japanese Patent Publication No. 35-8917, Japanese Patent Publication No. 36-9559, Japanese Patent Publication No. 36-9560), and those to which boric acid is added (US Patent No. 273319).
No. 9, 2780592), halogen (Cl ⁻ ,
The steel sheet has been subjected to cathodic electrolysis treatment using a bath containing various anions such as that containing F ⁻ (Japanese Patent Publication No. 39-14363).

As the coating type chromate, one coating a water-soluble chromium compound containing trivalent chromium as a main component, an inorganic colloidal compound and an acidic aqueous solution containing an inorganic anion (JP-A-63-218279), Cr ^6+. In which colloidal silica is mixed with chromic acid obtained by reducing a part of trivalent to trivalent (JP-A-63-243279), 3
What treats a liquid containing a water-soluble chromium compound containing valent chromium as a main component, an inorganic colloidal compound and an inorganic anion (JP-A-63-218279), chromic acid of a specific element and a colloidal compound in a specific ratio, and an inorganic Treating a liquid mixed with anions (Japanese Patent Laid-Open No. 178873/1988)
Gazette), those treated with a liquid containing chromic acid and an inorganic colloid and an inorganic anion having a specified Cr ⁶⁺ / (Cr ⁶⁺ + Cr ³⁺ ) ratio, SiO ₂ and PO ₄ ^3- trivalent / total C
What treats an aqueous chromic acid solution in which the molar ratio of r is regulated (Japanese Patent Laid-Open No. 1-65272), a specific amount of silicofluoride containing hexavalent and trivalent chromium ions containing a specific amount of trivalent chromium ions. And a solution containing each sodium salt of fluoride (JP-A-1-56879),
Which process an aqueous solution containing a SiO ₂ of a specific amount with respect to hexavalent and trivalent chromium ions containing trivalent chromium ions of a particular amount (JP-A-1-56877), a specific amount of trivalent Treatment of a solution containing a specific amount of ammonium silicofluoride and a silane coupling agent with respect to hexavalent and trivalent chromium ions containing chromium ions (JP-A-1)
-56878), which contains a specific proportion of chromium and silica sol, and treats a liquid in which the amount of Cr ⁶⁺ and the silica sol particle size are specified (Japanese Patent Laid-Open No. 2-104672), specific proportions of chromium ion, phosphoric acid, Treatment of a liquid containing a silicic acid sol and specifying hexavalent chromium ions in all chromium ions (JP-A-2-85372), chromic acid,
Treatment of a liquid containing an anhydrous colloidal compound and a silane coupling agent in a specific ratio (JP-A-3-146676), a liquid containing trivalent / hexavalent Cr and containing silica gel, phosphoric acid, and Zn. Processing (JP-A-3-687)
No. 83).

Also, although it is a kind of coating type chromate,
Coating type chromate added with organic resin, Cr specified as so-called resin chromate, amorphous silica,
A treatment method comprising a phosphoric acid compound and polyacrylic acid and specifying the C / Si ratio of the outermost surface layer of the film (Japanese Patent Laid-Open No. 163/163).
385), a method in which an acrylic emulsion of a copolymer such as methyl methacrylate is added to a chromate solution under specific conditions (JP-A-2-179883), chromic acid, a chromic acid reduction product, and acrylic. A method of applying a liquid containing an emulsion and a silica sol under specific conditions (JP-A-3-215683), a method of treating a liquid containing a chromic acid, a chromic acid reduction product, an acrylic emulsion, and a wet type silica sol under specific conditions. (JP-A-3-215681) and the like.

Of the chromate coatings, the chromate coating formed by electrolysis does not have sufficient Cr elution, but its corrosion resistance is not sufficient, and the scratch resistance of the coating during processing is poor, and therefore the corrosion resistance after processing is low. Is extremely low. Further, it is not preferable to use the chromate film formed by the coating type as it is after treatment, because the chromate film is liable to elute, which causes troubles in pollution. In addition, the corrosion resistance and the adhesiveness of the coating are not always sufficient, and the coating is likely to be flawed during processing, and the corrosion resistance after processing is considerably reduced.

In the case of resin type chromate, various resins are added to the chromic acid bath. At this time, the strong reaction of chromic acid (Cr ⁶⁺ → Cr ³⁺ ) causes the reaction of the resin and the bath. Was difficult to maintain stable. When many resins are added to a chromic acid bath, short ones are oxidized within a few seconds, and long ones are oxidized within a few hours at most, and coarsen to precipitate or gel. Therefore, the bath cannot be used, and the formed resin chromate film is difficult to form a film of a certain component. Thus, it has been said that an industrially usable resin chromate is impossible because a resin stable in a chromic acid bath has not existed until now.

Further, even if a known steel chromate is applied to a steel sheet within a short time after the bath is constructed, the formed chromate film is likely to be partly eluted in a degreasing bath or a chemical bath, which causes troubles in pollution. Not preferable. Moreover, the corrosion resistance and the paint adhesion are not always sufficient. In order to succeed in resin chromate, first of all, it is necessary to develop a resin that is extremely stable in a chromic acid bath, and when applied to a steel sheet, has excellent performance such as corrosion resistance and paint adhesion. .
Up to now, no resin satisfies all the above conditions.

[0008]

On the other hand, the present invention solves the above-mentioned drawbacks of the prior art. No elution of chromate is observed even after naked use after chromate treatment. Shows extremely excellent bare corrosion resistance. It is possible to secure excellent adhesion with the organic paint. Further, if desired, it has excellent scratch resistance during processing and maintains extremely excellent corrosion resistance even after processing. Excellent fingerprint resistance. It is a first object of the present invention to provide an extremely stable resin chromate bath capable of exhibiting such characteristics as described above and forming a chromate film on a cold-rolled steel sheet or a Zn or Zn-based alloy plated steel sheet. Is. The second purpose is to provide bare corrosion resistance, paint adhesion, Cr elution resistance, and, if desired, scratch resistance and fingerprint resistance after cold bath steel or Zn or Zn alloy plated steel sheet by the above treatment bath. It is intended to provide a surface-treated steel sheet which is excellent in bare corrosion resistance after coating, a coating adhesion property, a Cr elution resistance, and if desired, a scratch resistance and a fingerprint resistance, which are obtained by forming a specific amount of an excellent chromate film.

The third purpose is cold rolled steel or Zn.
Or, a specific amount of a chromate film is formed on the Zn-based alloy-plated steel sheet by the above treatment bath, and a specific amount of a specific organic resin is applied on the chromate film to further improve the scratch resistance of the chromate film. It is intended to provide a surface-treated steel sheet which is further excellent in corrosion resistance afterwards and is excellent in paint adhesion and Cr elution resistance. A fourth object is to form a specific amount of a chromate film on a cold rolled steel plate or a Zn or Zn-based alloy plated steel plate by the above treatment bath, and further to deposit SiO ₂ , SnO ₂ , Cr ₂ O ₃ , Fe ₂ O _{3 on it.} , Fe
_A specific amount of organic resin mixed with colloid (sol) or powder of ₃ O ₄ , MgO, Al ₂ O ₃ is applied to further improve the scratch resistance of the above chromate film and to improve the corrosion resistance after processing. It is intended to provide a surface-treated steel sheet which is excellent in paint adhesion and Cr elution resistance.

[0010]

That is, the present invention is based on trivalent Cr (Cr ₂ O ₃ and / or Cr (OH) ₃ ), hexavalent C
Chromic acid such as r, phosphoric acid, special organic resin or a special resin chromate film containing a special inorganic substance as a component is formed on various metals such as cold rolled steel plate or Zn or Zn-based alloy plated steel plate to elute chromate. No corrosion, bare corrosion resistance and paint adhesion after processing, and if desired, scratch resistance,
It is an extremely stable resin chromate treatment bath that forms a resin chromate film that has excellent fingerprint resistance and adhesion to various organic resins. It is the stability of the special organic resin in chromic acid that provides the life of this extremely stable processing bath, in other words, the extremely long processing bath.The formed chromate film is formed of the special organic resin and chromic acid, phosphoric acid, or even a special organic resin. It has been found that the synergistic effect of the inorganic substance can impart extremely excellent paint adhesion, bare corrosion resistance after processing, and fingerprint resistance.

The special organic resin is methyl methacrylate, butyl acrylate, glycidyl methacrylate,
It is an organic resin obtained by copolymerizing methacrylic acid and acrylic acid as main components and, if desired, a phosphoric acid group-containing vinyl monomer and hydroxyethyl methacrylate. However, the term “copolymerized organic resin” as used herein means a monomer as a main component, that is, methyl methacrylate, butyl acrylate, glycidyl methacrylate,
Methacrylic acid, acrylic acid, and optionally a vinyl group-containing vinyl-based monomer, or a polymer synthesized by copolymerizing hydroxyethyl methacrylate, if desired, all of these monomers forming a single copolymer. Needless to say, it does not need to be copolymerized, and may be a copolymer composed of a proper combination of these monomers. Further, an aqueous organic resin emulsion is desirable as the form of the organic resin, and an aqueous dispersion of a polymer synthesized by an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method or a solution polymerization method is used as a synthesis method of the aqueous organic resin emulsion. There are laws, but
From the viewpoint of the stability of the organic resin in the chromate treatment bath, the soap-free emulsion polymerization method using no surfactant is preferable.

[0012] Here, a general resin may become unusable (belonging to a bath life) due to coarsening of the particle size in a chromic acid bath or gelation in a very short time to a short time such as several seconds to several hours. On the other hand, when methyl methacrylate, butyl acrylate, glycidyl methacrylate, methacrylic acid and acrylic acid and, if desired, a phosphoric acid group-containing vinyl monomer and hydroxyethyl methacrylate are copolymerized, the blending ratio of each copolymerization component can be determined. Regardless of, it is possible to obtain an extremely stable resin in the chromic acid bath,
The chromate bath consisting of an aqueous solution containing the above resin in chromic acid and phosphoric acid has a very long life and is industrially usable. An aqueous solution containing the above resin in chromic acid and phosphoric acid is applied to a Zn-plated steel sheet. By doing so, it is possible to form a resin chromate film having excellent paint adhesion and, if desired, excellent fingerprint resistance and scratch resistance.

Further, when the special organic resin is obtained from the copolymerization of methyl methacrylate, butyl acrylate, glycidyl methacrylate, methacrylic acid and acrylic acid, the preferable blending ratio (weight ratio) of each copolymerization component is shown. And 5 to 40 parts of methyl methacrylate, 15 to 55 parts of butyl acrylate, 3 to 3 of glycidyl methacrylate.
30 parts, methacrylic acid 10 to 45 parts and acrylic acid 1
~ 20 copies. Further, when the special organic resin is obtained by further adding hydroxyethyl methacrylate to the above-mentioned 5 kinds of monomers, the preferable mixing ratio (weight ratio) of each copolymerization component is as follows:
30 parts, butyl acrylate 20 to 50 parts, glycidyl methacrylate 3 to 25 parts, methacrylic acid 10 to 40
Parts, 1 to 20 parts of acrylic acid, and 3 to 25 parts of hydroxyethyl methacrylate. Further, when the special organic resin is obtained by further adding a phosphoric acid group-containing vinyl monomer to the above-mentioned 5 kinds of monomers, the preferable mixing ratio (weight ratio) of each copolymerization component is as follows: 6-40 parts, butyl acrylate 25-50 parts, glycidyl methacrylate 3-20 parts, methacrylic acid 1
0 to 30 parts, acrylic acid 1 to 20 parts, and phosphoric acid group-containing vinyl monomer 0.05 to 5 parts.

The above-mentioned special organic resin is extremely stable in an aqueous liquid containing chromic acid and phosphoric acid, and the special organic resin and chromic acid synthesized by copolymerization in the mixing ratio of the above-mentioned copolymerization components. When an aqueous solution mixed with and phosphoric acid is applied to a Zn-plated steel sheet, a resin chromate film excellent in paint adhesion, scratch resistance and fingerprint resistance can be formed.

Moreover, the above range of numerical limitation is due to the following reason. That is, the copolymerizable range of methyl methacrylate in the special organic resin is 50 parts,
The limits were 60 parts for butyl acrylate, 40 parts for glycidyl methacrylate, 50 parts for methacrylic acid, and 25 parts for acrylic acid. Therefore, within the respective limit values, the preferable blending ratio of each copolymerization component is, as described above, 5 to 40 parts of methyl methacrylate, 15 to 55 parts of butyl acrylate, 3 to 30 parts of glycidyl methacrylate, and methacrylic acid. In 10 to 45 parts of acid and 1 to 20 parts of acrylic acid, it exhibits extremely excellent paint adhesion, bath stability and, if necessary, more fingerprint resistance, and is less than 40 parts or less than 40 parts of methyl methacrylate which is out of the range. More than 15 parts, butyl acrylate less than 15 parts or more than 55 parts, glycidyl methacrylate less than 3 parts or more than 30 parts,
If less than 10 parts or more than 45 parts of methacrylic acid and less than 1 part or more than 20 parts of acrylic acid, the paint adhesion, the bath stability and, if necessary, the fingerprint resistance are slightly lowered, but they are excellent. The result was confirmed.

When the special organic resin is obtained by further adding hydroxyethyl methacrylate to the above-mentioned 5 kinds of monomers, the preferable mixing ratio of each copolymerization component is 1 to 30 parts of methyl methacrylate, acrylic acid. Butyl acid 20 to 50 parts, glycidyl methacrylate 3 to 2
5 parts, methacrylic acid 10 to 40 parts, acrylic acid 1 to 2
The limit value was 0 part, and the range in which hydroxyethyl methacrylate could be copolymerized was 30 parts. Therefore, in the limit value, when hydroxyethyl methacrylate is 3 to 25 parts, the paint adhesion is extremely excellent, and when the hydroxyethyl methacrylate is less than 3 parts or more than 25 parts, the paint adhesion is slightly lowered but excellent. It was confirmed.

Further, when the special organic resin is obtained by further adding a phosphoric acid group-containing vinyl monomer to the above-mentioned five kinds of monomers, a preferable mixing ratio of each copolymerization component is 6 to 40 parts of methyl methacrylate. Butyl acrylate 2
5 to 50 parts, glycidyl methacrylate 3 to 20 parts,
Methacrylic acid was 10 to 30 parts, acrylic acid was 1 to 20 parts, and 6 parts was the limit value in the range in which the phosphoric acid group-containing vinyl-based monomer could be copolymerized. Therefore, at the limit value, the vinyl group-containing vinyl monomer is 0.05 to
It was confirmed that in the case of 5 parts, the paint adhesion was extremely excellent, and when the phosphoric acid group-containing vinyl-based monomer was less than 0.05 parts or more than 5 parts, the paint adhesion was slightly lowered, but it was confirmed to be excellent.

Next, chromic acid and phosphoric acid in the present invention
The compounding amount of chromic acid is 5 parts with respect to 100 parts of the special organic resin.
˜50 parts and phosphoric acid 10 to 60 parts. Chromic acid and
When the compounding amount of phosphoric acid was within these ranges, it was extremely excellent.
After processing, bare corrosion resistance, excellent Cr elution resistance and excellent paint density
Adhesion is exhibited, but chromic acid or phosphoric acid is within these ranges
Outside, there is a tendency for bare corrosion resistance to decrease after processing, and phosphoric acid
Is less than 10 to 60 parts, the coating adhesion tends to decrease.
It is in. Also, chromic acid exceeds 50 parts or phosphoric acid
If it is less than 10 parts, the Cr elution resistance tends to be poor.
In the present invention, an aqueous liquid containing the above chromic acid and phosphoric acid
And also SiO₂, SnO₂, Cr₂O₃, Fe₂O
₃, Fe₃O_Four, MgO, Al₂O₃, ZrO ₂Etc.
Lloyd (sol) or one or more powders
Mix 5 to 30 parts with 100 parts of special organic resin
Can be. 5 to 5 of the above colloid (sol) or powder
After processing at 30 parts, the bare corrosion resistance is further improved and exceeds 30 parts.
If so, Cr elution resistance and paint adhesion tend to decrease.
It

With respect to 100 parts of the special organic resin according to the present invention, 5 to 50 parts of chromic acid and 10 to 60 parts of phosphoric acid are added, or further SiO ₂ , SnO ₂ , Cr ₂ O ₃ and Fe _{2 are} added.
_{O 3, Fe 3 O 4,} MgO, Al 2 O 3, of ZrO ₂ colloid (sol) or the life of one or two or more consisting of an aqueous bath containing a combination of 5 to 30 parts bath powders outstanding, e.g. There is no change when left at 50 ° C for at least 5 days. This means how stable the special organic resin of the present invention is in the chromic acid bath because the resin chromate bath known in the prior art precipitates or gels the resin in several hours at the longest. Here, the special organic resin according to the present invention is extremely stable in chromic acid because when it is copolymerized with the components according to the present invention, a stable layer of protective colloid is formed on the surface layer of the formed organic resin, and the barrier layer forms chromium. This is because the reaction with ions is suppressed. Further, even if the colloid is added, the colloid cannot be adsorbed or reacted due to the presence of the barrier layer, so that it is considered that the stability of the resin is maintained as it is.

The adhesion amount of the resin chromate film is 10 mg / m ² or more in terms of Cr, and the upper limit is C from the economical point of view.
It is 300 mg / m ² or less in terms of r. Further, even when colloidal silica is added to the above aqueous liquid, the relationship between the Cr adhesion amount and the bare corrosion resistance after processing, paint adhesion is almost unchanged, and the Cr elution resistance is not affected by the Cr adhesion amount,
If it is 10 mg / m ² or more in terms of Cr, excellent bare corrosion resistance and paint adhesion after processing can be obtained. Next, the resin chromate treatment bath according to the present invention is treated on a cold-rolled steel sheet or a Zn or Zn-based alloy plated steel sheet to obtain extremely excellent corrosion resistance, paint adhesion and Cr elution resistance, and further fingerprint resistance. Although it forms a resin chromate film that shows, since this resin chromate film has extremely excellent adhesion to other organic resins, it is also possible to apply various organic resins on it to produce an organic composite steel sheet. it can.

As the organic resin applied to the upper layer, methyl methacrylate, butyl acrylate, glycidyl methacrylate, methacrylic acid and acrylic acid are essential components, and if desired, a phosphoric acid group-containing vinyl monomer or hydroxyethyl methacrylate is used. Special organic resin obtained by copolymerization, olefin / acrylic acid copolymer resin,
Polyacrylic acid and its copolymer resin, polyacrylic acid ester and its copolymer resin, polymethacrylic acid ester and its copolymer resin, epoxy resin, acrylic modified epoxy resin, ester modified epoxy resin, urethane modified epoxy resin, Urethane-modified epoxy ester resin, vinyl-modified epoxy resin, vinyl-modified epoxy ester resin and the like can be used.

Further, SiO is added to these resins.₂, SnO₂,
Cr₂O₃, Fe₂O₃, Fe₃O _Four, MgO, Al₂
O₃, ZrO₂Colloid (sol) or powder
Alternatively, two or more kinds may be added and applied. So
At the time of the treatment, these sols or powders were added to 100 parts of the organic resin.
However, it is desirable to add 10 to 60 parts. The reason is,
Corrosion resistance is slightly reduced if less than 10 parts or more than 60 parts
It is. The particle size of the sol or powder is 2-1.
It is more effective to use fine particles of around 5 nm
It turned out to be obtained. Therefore, in the present invention, the sol or
The particle size of the powder is preferably 2 to 15 nm. Well
In addition, the organic resin applied to the upper layer or the organic resin and the above
When applying the mixture of organic substances, the applied amount is 0.2-
3.0 g / m² It is desirable to apply so that
The reason is 0.2 g / m² Below is the skin that forms on the upper layer
The effect of the film is not sufficient, 3.0g / m² Ultra weldability
This is because the harmful effect appears in the point of. Therefore, in the present invention,
The amount of the coating formed on the layer is 0.2 to 3.0 g / m² When
I do.

The present invention has so far mainly been described in the case of processing an electro-Zn plated steel sheet. However, in the present invention, in addition to the electric Zn-plated steel sheet, cold-rolled steel sheet, hot-dip Zn-plated steel sheet and Zn-Ni-based, Zn-Ni-Co-based, Zn-Ni-
Cr-based, Zn-Fe-based, Zn-Co-based, Zn-Cr-based,
It can be used for Zn-based alloy plated steel sheets such as Zn-Mn-based, Zn-Al-based, and Zn-Mg-based. Further, in order to apply the resin chromate bath according to the present invention to the steel sheet, any coating method such as roll coating, spray coating, brush coating, dip coating and curtain flow may be used.

[0024]

EXAMPLES Hereinafter, examples will be described in detail. In addition,
The evaluation method in the present invention was as follows. (1) Stability of chromate bath Stability of the bath was allowed to stand at 50 ° C., and gelation of the bath or precipitation of the resin was observed. ◎: stable for 10 days or more ◯: stable for 5 days to less than 10 days Δ: stable for 1 day to less than 5 days ×: stable for 1 hour to less than 1 day xx: stable for less than 1 hour

(2) Bare corrosion resistance after processing Bare corrosion resistance after processing was evaluated by performing a cylindrical drawing process with a drawing depth of 50 mm and then performing a corrosion test to determine the occurrence of red rust on the side surface subjected to the drawing process. . Corrosion test is JIS-Z-
1000 by salt spray test according to 2371 standard (salt water concentration 5%, tank temperature 35 ° C, spray pressure 20 psi)
The rusting condition after a lapse of time is shown, and is evaluated in 5 grades of ◎, 〇, △, ×, XX, and ◎ is the best. ◎: Red rust occurrence rate 0% ○: 〃 more than 0% to 1% △: 〃 more than 1% to 10% ×: 〃 more than 10% to 50% XX more than 50%

(3) Adhesion of coating material Adhesion with a coating material was obtained by spraying a melamine-based low-temperature baking coating (baking temperature: 110 ° C) onto the obtained chromate film and then spray-coating to 30 μm, and then boiling water. Three
Immersion was carried out for 0 minutes, and then the coating film was cut on a 2 mm goggle and the tape was peeled off, and the peeled area of the coating film was evaluated. ◎: Coating film peeling area 0% 〇: 〃 more than 0% to 1% △: 〃 more than 1% to 10% ×: 〃 more than 10% to 50% XX: more than 50%

(4) Cr elution resistance Cr elution was obtained by immersing the obtained chromate film in distilled water at 100 ° C. for 30 minutes, and measuring the Cr weight loss before and after the treatment by fluorescent X-ray. ◎: Cr weight loss 0~1mg / m ² ○: 〃 1mg / m ² ultra ~5mg / m ² △: 〃 5mg / m ² ultra ~10mg / m ² ×: 〃 10mg / m ² ultra ~50mg / m ² × × 〃 More than 50 mg / m ² Here, Cr in the chromate film formed after drying is 6
It exists in the trivalent and trivalent states, but these total Crs were converted to chromic acid and displayed.

(5) Fingerprint resistance The fingerprint resistance was evaluated by observing it with the naked eye and observing it with the naked eye. ⊚: No fingerprints are recognized. ○: 〃 Slightly recognized. △: 〃 Partially recognized. ×: 〃 accepted. XX: 〃 It is clearly recognized.

EXAMPLE 1 15 parts of methyl methacrylate, 35 parts of butyl acrylate, 10 parts of glycidyl methacrylate, 40 parts of methacrylic acid and 3 parts of acrylic acid were co-coated on a Zn-plated steel sheet (weight per unit area: 20 g / m ² ). An aqueous liquid containing 20 parts of chromic acid and 35 parts of phosphoric acid was coated on a roll with 100 parts of the organic resin obtained by polymerization, and dried at 150 ° C. to obtain 100 parts of the organic resin, Chromic acid equivalent 20 parts Phosphoric acid 35 parts formed a chromate film with an adhesion amount of 58 mg / m ^{2 in} terms of Cr.

Example 2 Zn-Ni alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Ni = 13.1%), methyl acrylate 20 parts, butyl acrylate 40 parts, glycidyl methacrylate 2
Chromic acid was added to 100 parts of an organic resin obtained by copolymerizing 0 part, 55 parts of methacrylic acid and 5 parts of acrylic acid.
Part, phosphoric acid 35 parts, and an aqueous liquid containing 20 parts of colloidal silica are applied by a roll and dried at 150 ° C., and the components are 100 parts of the above-mentioned organic resin, 20 parts of total Cr in terms of chromic acid, and 35 parts of phosphoric acid SiO _In 20 parts, a chromate film having a Cr deposition amount of 68 mg / m ^{2 in} terms of Cr was formed.

Example 3 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 13.8%), methyl methacrylate 35 parts, butyl acrylate 55 parts, glycidyl methacrylate 1
Chromic acid is added to 100 parts of an organic resin obtained by copolymerizing 0 part, 55 parts of methacrylic acid and 2 parts of acrylic acid.
Part, 30 parts of phosphoric acid was mixed with an aqueous liquid, and 1
After drying at 50 ° C., 100 parts of the above organic resin, 25 parts of total Cr in terms of chromic acid and 30 parts of phosphoric acid, and a chromate film having an adhesion amount of 52 mg / m ^{2 in} terms of Cr was formed. Furthermore, on it, an aqueous solution of an organic resin obtained by copolymerizing 30 parts of methyl methacrylate, 50 parts of butyl acrylate, 25 parts of glycidyl methacrylate, 40 parts of methacrylic acid and 15 parts of acrylic acid was rolled. It was applied and dried at 150 ° C. to manufacture an organic composite plated steel sheet having a film made of the above organic resin of 1.1 g / m ² .

Example 4 Zn-Fe alloy plated steel sheet (Basis weight: 20 g / m ² ,
Fe = 12.4%) 5 parts methyl methacrylate, 20 parts butyl acrylate, 5 glycidyl methacrylate
Part, 20 parts of methacrylic acid, and 100 parts of an organic resin obtained by copolymerizing 10 parts of acrylic acid with 25 parts of chromic acid.
Part, 45 parts of phosphoric acid was mixed with an aqueous solution, and 1
After drying at 60 ° C., 100 parts of the above organic resin, 25 parts of total Cr in terms of chromic acid and 45 parts of phosphoric acid, and a chromate film having an adhesion amount of 73 mg / m ^{2 in} terms of Cr was formed. Further thereon, 10 parts of methyl methacrylate, 20 parts of butyl acrylate, 5 parts of glycidyl methacrylate, 15 parts of methacrylic acid and 5 parts of acrylic acid.
To 100 parts of an organic resin obtained by copolymerizing 100 parts of the same, an aqueous liquid containing 25 parts of colloidal silica is applied by a roll and dried at 160 ° C. to consist of 100 parts of the organic resin and 25 parts of colloidal silica. An organic composite plated steel sheet having a coating of 1.3 g / m ² was produced.

Example 5 Zn-Mg alloy plated steel sheet (Basis weight: 30 g / m ² ,
(Mg = 1.0%) 15 parts of methyl methacrylate, 35 parts of butyl acrylate, 10 parts of glycidyl methacrylate
Part, 100 parts of an organic resin obtained by copolymerizing 40 parts of methacrylic acid and 5 parts of acrylic acid with 15 parts of chromic acid
Part, 33 parts of phosphoric acid was mixed with an aqueous liquid, and 1
After drying at 50 ° C., 100 parts of the above organic resin, 15 parts of total Cr in terms of chromic acid and 33 parts of phosphoric acid, and a chromate film having an adhesion amount of 58 mg / m ^{2 in} terms of Cr was formed. Further, an aqueous solution of vinyl-modified epoxy resin was applied onto it by a roll and dried at 150 ° C. to produce an organic composite plated steel sheet having a film of vinyl-modified epoxy resin of 1.1 g / m ² .

Example 6 Zn-Mn alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Mn = 45.3%), 20 parts of methyl methacrylate, 35 parts of butyl acrylate, 1 of glycidyl methacrylate
Chromic acid 25 parts to 100 parts of an organic resin obtained by copolymerizing 5 parts, 60 parts methacrylic acid and 8 parts acrylic acid
Part, 60 parts of phosphoric acid was mixed with an aqueous liquid, and 1
After drying at 50 ° C., 100 parts of the above organic resin, 25 parts of total Cr in terms of chromic acid and 60 parts of phosphoric acid, and a chromate film having an adhesion amount of 43 mg / m ^{2 in} terms of Cr was formed. Furthermore, 25 parts of colloidal silica was added to 100 parts of the olefin / acrylic acid copolymer resin.
1 part of the aqueous liquid is coated with a roll and dried at 150 ° C. to form a coating film composed of 100 parts of olefin / acrylic acid copolymer resin and 25 parts of colloidal silica at 1.6 g / m ²
The organic composite plated steel sheet having the above was manufactured.

Example 7 Zn-Ni alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Ni = 12.7%), methyl methacrylate 35 parts, butyl acrylate 40 parts, glycidyl methacrylate 2
Chromic acid is added to 100 parts of an organic resin obtained by copolymerizing 0 part, 40 parts of methacrylic acid and 5 parts of acrylic acid.
Parts, phosphoric acid 25 parts, colloidal silica 15 parts, MgO3
1 part of the above organic resin is 100 parts of total Cr in terms of chromic acid, 25 parts of phosphoric acid, 25 parts of SiO _2, 15 parts of MgO, and 3 parts of adhered amount. Formed a chromate film of 53 mg / m ^{2 in} terms of Cr. Furthermore, an aqueous liquid of an organic resin obtained by copolymerizing 20 parts of methyl methacrylate, 30 parts of butyl acrylate, 20 parts of glycidyl methacrylate, 35 parts of methacrylic acid and 10 parts of acrylic acid on a roll is further rolled. It was applied and dried at 150 ° C. to produce an organic composite plated steel sheet having a coating film of the above organic resin of 1.2 g / m ² .

Example 8 Zn-Ni alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Ni = 11.6%), methyl methacrylate 20 parts, butyl acrylate 45 parts, glycidyl methacrylate 2
Chromic acid 15 parts to 100 parts organic resin obtained by copolymerizing 0 parts, 50 parts methacrylic acid and 5 parts acrylic acid
Part, phosphoric acid 35 parts, colloidal silica 20 parts mixed with an aqueous liquid applied by a roll and dried at 150 ° C., and the components are 100 parts of the above-mentioned organic resin 15 parts by total chromic acid conversion 15 parts phosphoric acid 35 parts SiO ₂ In 20 parts, a chromate film having an adhesion amount of 63 mg / m ^{2 in} terms of Cr was formed. Furthermore, to 100 parts of an organic resin obtained by copolymerizing 35 parts of methyl methacrylate, 30 parts of butyl acrylate, 20 parts of glycidyl methacrylate, 20 parts of methacrylic acid and 10 parts of acrylic acid on it.
Apply an aqueous solution containing 15 parts of Aerosil on a roll,
After drying at 150 ° C., an organic composite plated steel sheet having a coating film consisting of 100 parts of the above organic resin and 15 parts of Aerosil was 1.4 g / m ² was produced.

Example 9 Zn-Cr alloy plated steel sheet (Basis weight: 20 g / m ² ,
Cr = 12.1%), methyl methacrylate 30 parts, butyl acrylate 55 parts, glycidyl methacrylate 1
Chromic acid 20 parts to 100 parts organic resin obtained by copolymerizing 0 parts, 30 parts methacrylic acid and 8 parts acrylic acid
Parts, phosphoric acid 35 parts, colloidal silica 20 parts, MgO1
1 part of the above-mentioned organic resin is 100 parts of total Cr in terms of chromic acid 20 parts phosphoric acid 35 parts SiO ₂ 20 parts MgO 1 part, and the amount of adhesion is Cr A converted chromate film of 60 mg / m ² was formed. Further, an aqueous solution of vinyl-modified epoxy ester resin was applied onto it by a roll and dried at 140 ° C. to produce an organic composite plated steel sheet having a film of vinyl-modified epoxy ester resin of 1.6 g / m ² .

Example 10 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 12.7%), methyl methacrylate 15 parts, butyl acrylate 25 parts, glycidyl methacrylate 1
Chromic acid 30 parts to 100 parts organic resin obtained by copolymerizing 5 parts, 40 parts methacrylic acid and 5 parts acrylic acid
Part, phosphoric acid 30 parts, and colloidal silica 25 parts were mixed with an aqueous solution by means of a roll and dried at 150 ° C. to obtain 100 parts of the above organic resin. Total Cr in terms of chromic acid 30 parts Phosphoric acid 30 parts SiO ₂ At 25 parts, a chromate film having an adhesion amount of 58 mg / m ^{2 in} terms of Cr was formed. Furthermore, 100 parts of urethane-modified epoxy ester resin and 15 parts of Aerosil were mixed with an aqueous solution by a roll and dried at 150 ° C. to obtain 100 parts of urethane-modified epoxy ester resin and 1 part of Aerosil.
An organic composite plated steel sheet having a coating consisting of 5 parts and 1.3 g / m ² was produced.

Comparative Example 1 A Zn-plated steel sheet was coated with an aqueous liquid containing 25 parts of chromic acid and 50 parts of phosphoric acid by a roll and dried at 150 ° C. to form a chromate film having an adhesion amount of 68 mg / m ^{2 in} terms of Cr. did.

Comparative Example 2 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 12.1%), chromic acid 30 parts, phosphoric acid 45 parts,
Apply 20 parts of colloidal silica aqueous liquid with a roll and
It was dried at 60 ° C. to form a chromate film having an adhesion amount of 58 mg / m ^{2 in} terms of Cr.

Comparative Example 3 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%) and 100 parts of acrylic emulsion,
Aqueous liquid containing 20 parts of chromic acid and 40 parts of phosphoric acid was applied on a roll and dried at 160 ° C. to obtain acrylic resin 100 parts. Total Cr was 20 parts in terms of chromic acid. 40 parts Phosphoric acid was 40 parts. A converted chromate film of 62 mg / m ² was formed.

Comparative Example 4 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%), an aqueous solution prepared by mixing 100 parts of acrylamide resin, 35 parts of chromic acid, 35 parts of phosphoric acid, and 25 parts of Aerosil is coated with a roll and dried at 150 ° C. to obtain 100 parts of acrylamide resin. Chromate film was formed with 35 parts of Cr in terms of chromic acid and 35 parts of phosphoric acid in 25 parts of SiO ₂ with an adhesion amount of 68 mg / m ^{2 in} terms of Cr.

Comparative Example 5 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.8%) with 100 parts of acrylic amide resin,
An aqueous solution containing 20 parts of chromic acid and 30 parts of phosphoric acid was applied by a roll and dried at 150 ° C. to obtain a component. Acrylic amide resin 100 parts Total Cr in terms of chromic acid 20 parts Phosphoric acid 30 parts A chromate film of 68 mg / m ^{2 in} terms of Cr was formed. Further, an aqueous solution of an epoxy resin was applied onto it by a roll and dried at 150 ° C. to produce an organic composite plated steel sheet having a coating of the epoxy resin of 1.5 g / m ² .

Comparative Example 6 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 11.7%) with 100 parts of acrylic emulsion,
Chromic acid 20 parts, phosphoric acid 35 parts, colloidal silica 25
1 part acrylic resin 100 parts total Cr in terms of chromic acid 20 parts phosphoric acid 35 parts SiO ₂ 25 parts and the amount of adhesion is 52 mg / in terms of Cr A chromate film of m ² was formed. Further thereon, an aqueous solution prepared by mixing 20 parts of Aerosil with 100 parts of epoxy resin is coated with a roll and dried at 150 ° C. to form a film of 100 parts of epoxy resin and 20 parts of Aerosil at 1.3 g / m 2. An organic composite plated steel sheet having ² was manufactured. Table 1 shows Zn or Z
Bare corrosion resistance after processing by the salt spray test of Examples 1 to 10 and Comparative Examples 1 to 6 when processed into n-based alloy plated steel sheets, melamine-based low temperature baking type coating (baking temperature: 110 ° C)
It shows the paint adhesion, Cr elution resistance and bath stability when 30 μm was applied.

[0045]

[Table 1]

As is clear from Table 1, when the chromate according to the present invention is applied to the Zn-plated steel sheet, bare corrosion resistance after processing hardly changes after 1000 hours, and a small amount of red rust occurs at 1500 hours. There are only a few things. When the chromate according to the present invention is applied to a Zn-based alloy-plated steel sheet, bare corrosion resistance after processing hardly changes after 1500 hours, and only a small amount of red rust is generated at 2000 hours. Further, the bare corrosion resistance after processing in the case of the organic composite plated steel sheet on which the chromate according to the present invention was carried out, and further the organic resin according to the present invention was further carried out, a slight red rust was observed in some samples after 4000 hours. There is only something.

On the other hand, in the case of the known chromate film composition (Comparative Examples 1 and 2), red rust was considerably generated after 100 hours of SST. Further, the resin chromates other than the present invention to which various resins are added (Comparative Examples 3 and 4) also generate considerable red rust in 400 hours. Further, the adhesiveness of the coating film is also the same, and when the present invention is carried out, even a low temperature baking type (110 ° C. baking), which is difficult to obtain the adhesiveness of the paint, shows extremely excellent adhesiveness. Example 1,
In the case of 2) or the resin chromates other than the present invention (Comparative Examples 3 and 4), the paint adhesion is extremely poor. Also in terms of the Cr elution property, when the present invention is carried out, almost no Cr elution occurs. On the other hand, in the case of the known chromate film (Comparative Examples 1 and 2) and the resin chromate other than the present invention (Comparative Examples 3 and 4), a large amount of Cr was found to be eluted. Further, the resin chromate bath according to the present invention (Example 1
The bath life of 10) is extremely long and does not change for a long time. On the other hand, resin chromate baths other than the present invention (Comparative Example 3,
The bath life of 4, 5, 6) is extremely short, and the resin gels and becomes unusable in an extremely short time.

Example 11 A Zn-plated steel sheet (area weight: 20 g / m ² ) had 5 parts of methyl methacrylate, 33 parts of butyl acrylate, 15 parts of glycidyl methacrylate, 30 parts of methacrylic acid, 3 parts of acrylic acid and hydroxy. Ethyl methacrylate 15
100 parts of organic resin obtained by copolymerizing 1 part, chromic acid 1
An aqueous liquid containing 5 parts of phosphoric acid and 30 parts of phosphoric acid was applied on a roll and dried at 150 ° C. to obtain 100 parts of the above organic resin, 15 parts of total Cr in terms of chromic acid, and 30 parts of phosphoric acid. A chromate film of 52 mg / m ^{2 in} terms of Cr was formed.

Example 12 Zn-Ni alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Ni = 12.8%), methyl methacrylate 10 parts, butyl acrylate 30 parts, glycidyl methacrylate 1
100 parts of an organic resin obtained by copolymerizing 5 parts, 35 parts of methacrylic acid, 5 parts of acrylic acid and 20 parts of hydroxyethyl methacrylate, 25 parts of chromic acid, 35 parts of phosphoric acid
Part, an aqueous liquid containing 15 parts of colloidal silica is applied by a roll and dried at 150 ° C., and the component is 100 parts of the above organic resin. 25 parts of total Cr in terms of chromic acid 35 parts of phosphoric acid SiO ₂ 15 parts of Cr A chromate film having an adhesion amount of 61 mg / m ^{2 in} terms of Cr was formed.

Example 13 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 11.8%) with 7 parts of methyl methacrylate, 45 parts of butyl acrylate, and 20 parts of glycidyl methacrylate.
Part, 45 parts of methacrylic acid, 7 parts of acrylic acid and 100 parts of an organic resin obtained by copolymerizing 30 parts of hydroxyethyl methacrylate, 25 parts of chromic acid, and 30 parts of phosphoric acid. After drying at 150 ° C., 100 parts of the above organic resin, 25 parts of total Cr in terms of chromic acid and 30 parts of phosphoric acid, and a chromate film having an adhesion amount of 63 mg / m ^{2 in} terms of Cr was formed. Further thereon, 10 parts of methyl methacrylate, 30 parts of butyl acrylate, 15 parts of glycidyl methacrylate, 25 parts of methacrylic acid, 1 part of acrylic acid.
An aqueous solution of an organic resin obtained by copolymerizing 0 part and 15 parts of hydroxyethyl methacrylate is coated with a roll,
1. Dry at 150 ° C. to form a film made of the above organic resin.
An organic composite plated steel sheet having 5 g / m ² was produced.

Example 14 Zn-Fe alloy plated steel sheet (Basis weight: 20 g / m ² ,
Fe = 12.1%), methyl methacrylate 10 parts, butyl acrylate 45 parts, glycidyl methacrylate 2
An aqueous solution containing 100 parts of an organic resin obtained by copolymerizing 0 part, 30 parts of methacrylic acid, 5 parts of acrylic acid and 20 parts of hydroxyethyl methacrylate, 15 parts of chromic acid, and 35 parts of phosphoric acid was applied by a roll. Then, it was dried at 160 ° C., and the components were 100 parts of the above organic resin, 15 parts of total Cr in terms of chromic acid and 35 parts of phosphoric acid, and a chromate film having an adhesion amount of 81 mg / m ^{2 in} terms of Cr was formed. Further thereon, 12 parts of methyl methacrylate, 25 parts of butyl acrylate, 20 parts of glycidyl methacrylate, 20 parts of methacrylic acid, 1 part of acrylic acid
An aqueous solution prepared by mixing 20 parts of colloidal silica with 100 parts of an organic resin obtained by copolymerizing 5 parts and 20 parts of hydroxyethyl methacrylate was coated with a roll, and
Dried at ℃ 100 parts organic resin and 20 colloidal silica
An organic composite plated steel sheet having 1.5 g / m ^{2 of} a coating composed of a part and a part was produced.

Example 15 Zn-Mg based alloy plated steel sheet (Basis weight: 30 g / m ² ,
(Mg = 1.0%), 3 parts of methyl methacrylate, 25 parts of butyl acrylate, 7 parts of glycidyl methacrylate,
An aqueous solution containing 100 parts of an organic resin obtained by copolymerizing 17 parts of methacrylic acid, 9 parts of acrylic acid and 8 parts of hydroxyethyl methacrylate, 15 parts of chromic acid, and 40 parts of phosphoric acid was applied on a roll, After drying at 0 ° C., 100 parts of the above organic resin, 15 parts of total Cr in terms of chromic acid and 40 parts of phosphoric acid, and a chromate film having an adhesion amount of 55 mg / m ^{2 in} terms of Cr was formed. Furthermore, an aqueous solution of vinyl-modified epoxy resin was applied onto it by a roll and dried at 150 ° C. to produce an organic composite plated steel sheet having a film of vinyl-modified epoxy resin of 0.9 g / m ² .

Example 16 Zn-Mn alloy plated steel sheet (Basis weight: 20 g / m ² ,
Mn = 45.3%), 10 parts of methyl methacrylate, 35 parts of butyl acrylate, 2 of glycidyl methacrylate
An aqueous solution containing 100 parts of an organic resin obtained by copolymerizing 3 parts, 20 parts of methacrylic acid, 2 parts of acrylic acid and 30 parts of hydroxyethyl methacrylate, 30 parts of chromic acid, and 50 parts of phosphoric acid is applied by a roll. Then, it was dried at 150 ° C., and the components were 100 parts of the above-mentioned organic resin, 30 parts of total Cr in terms of chromic acid and 50 parts of phosphoric acid, and a chromate film having an adhesion amount of 53 mg / m ^{2 in} terms of Cr was formed. Further, an aqueous liquid prepared by mixing 25 parts of colloidal silica with 100 parts of olefin / acrylic acid copolymer resin was coated on a roll and dried at 150 ° C. to obtain 100 parts of olefin / acrylic acid copolymer resin and colloidal. An organic composite plated steel sheet having a coating composed of 25 parts of silica of 1.9 g / m ² was produced.

Example 17 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m² ,
Ni = 13.1%), 5 parts of methyl methacrylate,
Butyl phosphate 40 parts, glycidyl methacrylate 22
Part, methacrylic acid 43 parts, acrylic acid 5 parts and hydro
Obtained by copolymerizing 33 parts of xyethyl methacrylate
100 parts organic resin, 20 parts chromic acid, 35 parts phosphoric acid,
Aqueous liquid containing 20 parts of colloidal silica and 3 parts of MgO
Is coated with a roll and dried at 150 ° C., and the component is 100 parts of the above organic resin.₂ 20 parts MgO 3 parts, adhesion amount is 68 mg / m in terms of Cr² Chromated leather
A film was formed. On top of that, methyl methacrylate
5 parts, butyl acrylate 25 parts, glycidyl methacrylate
Rate 5 parts, methacrylic acid 15 parts, acrylic acid 5 parts
And 5 parts of hydroxyethyl methacrylate
The aqueous liquid of the obtained organic resin is applied with a roll, and the temperature is 150 ° C.
And dried to give a film of 1.1 g / m
² The organic composite plated steel sheet having the above was manufactured.

Example 18 Zn-Ni alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Ni = 13.6%) 2 parts methyl methacrylate, 45 parts butyl acrylate, 20 glycidyl methacrylate
Part, 18 parts of methacrylic acid, 2 parts of acrylic acid and 100 parts of an organic resin obtained by copolymerizing 8 parts of hydroxyethyl methacrylate, 25 parts of chromic acid, 35 parts of phosphoric acid, 10 parts of colloidal silica Is applied by a roll and dried at 150 ° C., the components are 100 parts of the above organic resin, 25 parts of total Cr in terms of chromic acid, 35 parts of phosphoric acid, 35 parts of SiO _2, 10 parts of adhered amount of 58 mg / m ^{2 in} terms of Cr. A chromate film was formed. Further thereon, 28 parts of methyl methacrylate, 45 parts of butyl acrylate, 20 parts of glycidyl methacrylate, 35 parts of methacrylic acid, 1 part of acrylic acid
To 100 parts of an organic resin obtained by copolymerizing 8 parts and 20 parts of hydroxyethyl methacrylate, an aqueous solution containing 25 parts of Aerosil was applied by a roll, dried at 150 ° C., and 100 parts of the above organic resin. An organic composite plated steel sheet having a coating film of 1.2 g / m ² consisting of Aerosil 25 parts was produced.

Example 19 Zn-Cr alloy-plated steel sheet (weight per unit area: 20 g / m² ,
Cr = 11.2%) and 10 parts of methyl methacrylate,
Butyl acrylate 45 parts, glycidyl methacrylate 2
3 parts, methacrylic acid 45 parts, acrylic acid 8 parts and hydr
Obtained by copolymerizing 30 parts of roxyethyl methacrylate
Organic resin 100 parts, chromic acid 25 parts, phosphoric acid 45
Part, colloidal silica 20 parts, MgO 3 parts
The liquid is applied by a roll and dried at 140 ° C., and the component is 100 parts of the above-mentioned organic resin.₂ 20 parts MgO 3 parts, adhesion amount is 60 mg / m in terms of Cr² Chromated leather
A film was formed. Furthermore, vinyl-modified epoxy s
Aqueous liquid of tell resin is applied with a roll and dried at 140 ° C.
A film of vinyl modified epoxy ester 1.1
g / m ² The organic composite plated steel sheet having the above was manufactured.

Example 20 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m² ,
Ni = 12.0%) with 5 parts of methyl methacrylate,
Butyl phosphate 45 parts, glycidyl methacrylate 10
Part, methacrylic acid 45 parts, acrylic acid 9 parts and hydro
Obtained by copolymerizing 30 parts of xyethyl methacrylate
100 parts of organic resin, 25 parts of chromic acid, 40 parts of phosphoric acid,
Applying an aqueous liquid containing 15 parts of colloidal silica on a roll
Then, it is dried at 150 ° C., and the component is 100 parts of the above-mentioned organic resin. 25 parts of total Cr in terms of chromic acid₂ In 15 parts, the adhesion amount is 71 mg / m in terms of Cr.² Chromated leather
A film was formed. On top of that, urethane-modified epoxy
Water containing 100 parts of ester resin and 20 parts of Aerosil
Apply the liquid on a roll and dry at 150 ℃
Modified epoxy ester resin 100 parts and Aerosil 20 parts
1.3 g / m ² Having organic composite plating
A steel plate was manufactured.

Comparative Example 7 A Zn-plated steel sheet was coated with an aqueous liquid containing 20 parts of chromic acid and 45 parts of phosphoric acid by a roll and dried at 170 ° C. to form a chromate film having an adhesion amount of 62 mg / m ^{2 in} terms of Cr. did.

Comparative Example 8 Zn-Ni alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Ni = 12.3%), chromic acid 20 parts, phosphoric acid 45 parts,
Apply 20 parts of colloidal silica aqueous liquid with a roll and
It was dried at 50 ° C. to form a chromate film having an adhesion amount in terms of Cr of 53 mg / m ² .

Comparative Example 9 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%) and 100 parts of acrylic emulsion,
Aqueous liquid containing 20 parts of chromic acid and 35 parts of phosphoric acid was applied by a roll and dried at 150 ° C. to obtain acrylic resin 100 parts Total Cr in terms of chromic acid 20 parts Phosphoric acid 35 parts A converted chromate film of 53 mg / m ² was formed.

Comparative Example 10 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 11.8%), an aqueous solution prepared by mixing 100 parts of acrylamide resin, 15 parts of chromic acid, 45 parts of phosphoric acid, and 20 parts of Aerosil with a roll and drying at 160 ° C., and the components are 100 parts of acrylamide resin. A chromate film was formed with 15 parts of Cr in terms of chromic acid and 45 parts of phosphoric acid in 20 parts of SiO ₂ with an adhesion amount of 68 mg / m ^{2 in} terms of Cr.

Comparative Example 11 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%) with 100 parts of acrylic amide resin,
An aqueous solution containing 30 parts of chromic acid and 40 parts of phosphoric acid was applied by a roll and dried at 150 ° C. to obtain the components: 100 parts of acrylic amide resin, 30 parts of total Cr in terms of chromic acid, 40 parts of phosphoric acid A chromate film of 56 mg / m ^{2 in} terms of Cr was formed. Furthermore, an aqueous solution of an epoxy resin was applied onto it by a roll and dried at 150 ° C. to produce an organic composite plated steel sheet having a film made of an epoxy resin of 1.1 g / m ² .

Comparative Example 12 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%) and 100 parts of acrylic emulsion,
Chromic acid 15 parts, phosphoric acid 30 parts, colloidal silica 35
1 part acrylic resin 100 parts total Cr in terms of chromic acid 15 parts phosphoric acid 30 parts SiO ₂ 35 parts in an amount of adhesion of 58 mg / A chromate film of m ² was formed. Furthermore, an aqueous liquid containing 100 parts of epoxy resin and 30 parts of Aerosil is coated on it with a roll,
It was dried at 150 ° C. to produce an organic composite plated steel sheet having a film made of 100 parts of epoxy resin and 30 parts of Aerosil at 1.1 g / m ² . Table 2 shows bare corrosion resistance after processing by the salt spray test of Examples 11 to 20 and Comparative Examples 7 to 12 when a Zn or Zn-based alloy plated steel sheet is treated, a melamine-based low temperature baking type coating (baking temperature: 110 ° C). ) 30
It shows the paint adhesion, Cr elution resistance and bath stability when μ coating is applied.

[0064]

[Table 2]

As is clear from Table 2, when the chromate according to the present invention is applied to the Zn-plated steel sheet, bare corrosion resistance after processing hardly changes after 1000 hours, and a small amount of red rust occurs at 1500 hours. There are only a few things. When the chromate according to the present invention is applied to a Zn-based alloy-plated steel sheet, bare corrosion resistance after processing hardly changes after 1500 hours, and only a small amount of red rust is generated at 2000 hours. Further, the bare corrosion resistance after processing in the case of the organic composite plated steel sheet on which the chromate according to the present invention was carried out, and further the organic resin according to the present invention was further carried out, a slight red rust was observed in some samples after 4000 hours. There is only something.

On the other hand, in the case of the known chromate film composition (Comparative Examples 7 and 8), a considerable amount of red rust occurred after 100 hours of SST. Further, the resin chromates other than the present invention to which various resins were added (Comparative Examples 9 and 10) also showed considerable red rust in 400 hours. Further, the adhesiveness of the coating film is also the same, and when the present invention is carried out, even a low temperature baking type (110 ° C. baking), which is difficult to obtain the adhesiveness of the paint, shows extremely excellent adhesiveness. Example 7,
In the case of 8) or the resin chromate other than the present invention (Comparative Examples 9 and 10), the paint adhesion is extremely poor. Also in terms of the Cr elution property, when the present invention is carried out, almost no Cr elution occurs. On the other hand, in the case of the known chromate film (Comparative Examples 7 and 8) and the resin chromate other than the present invention (Comparative Examples 9 and 10), a large amount of Cr is eluted. The bath life of the resin chromate baths (Examples 11 to 20) according to the present invention is extremely long and does not change for a long time. On the other hand, the bath life of the resin chromate baths other than the present invention (Comparative Examples 9 to 12) is extremely short, and the resin gels and becomes unusable in an extremely short time.

Example 21 30 parts of methyl methacrylate, 37 parts of butyl acrylate, 10 parts of glycidyl methacrylate, 20 parts of methacrylic acid, 3 parts of acrylic acid and phosphorus were applied to a Zn-plated steel sheet (weight per unit area: 20 g / m ² ). Acid group-containing vinyl monomer 0.5
100 parts of the organic resin obtained by copolymerizing 100 parts of the above solution, an aqueous liquid containing 20 parts of chromic acid and 40 parts of phosphoric acid was coated on a roll and dried at 150 ° C. to obtain 100 parts of the above organic resin. A total of 20 parts by weight of chromic acid and 40 parts by weight of phosphoric acid formed a chromate film having an adhesion amount of 58 mg / m ^{2 in} terms of Cr.

Example 22 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 12.8%) 30 parts methyl methacrylate, 37 parts butyl acrylate, 1 glycidyl methacrylate 1
Chromic acid 20 parts, phosphoric acid 4 parts per 100 parts of the organic resin obtained by copolymerizing 0 parts, methacrylic acid 20 parts, acrylic acid 3 parts and phosphoric acid group-containing vinyl monomer 0.5 part
An aqueous solution containing 0 parts and 10 parts of colloidal silica was coated on a roll and dried at 150 ° C. to obtain 100 parts of the above organic resin, 20 parts of total Cr in terms of chromic acid, 40 parts of phosphoric acid, and 10 parts of SiO ₂ . A chromate film having an adhesion amount of 52 mg / m ^{2 in} terms of Cr was formed.

Example 23 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m² ,
Ni = 11.8%) and 30 parts of methyl methacrylate,
Butyl acrylate 37 parts, glycidyl methacrylate 1
0 parts, methacrylic acid 20 parts, acrylic acid 3 parts and phosphorus
Obtained by copolymerizing 0.5 parts of acid group-containing vinyl monomer
Chromic acid 20 parts, phosphoric acid 4 parts per 100 parts of organic resin
Apply 0 parts of the aqueous solution on a roll and dry at 150 ° C.
The component is 100 parts of the above organic resin, 20 parts of total Cr in terms of chromic acid, 40 parts of phosphoric acid, and the amount of adhesion is 45 mg / m in terms of Cr.² Chromated leather
A film was formed. On top of that, methyl methacrylate
20 parts, butyl acrylate 35 parts, glycidyl metaac
10 parts relate, 20 parts methacrylic acid, 1 acrylic acid
0 parts and 2 parts of a vinyl monomer containing a phosphoric acid group are copolymerized
The resulting organic resin aqueous solution is coated with a roll,
Drying at ℃, a coating of the above organic resin 1.3g / m
² The organic composite plated steel sheet having the above was manufactured.

Example 24 Zn-Fe alloy plated steel sheet (Basis weight: 20 g / m ² ,
(Fe = 12.1%), 30 parts of methyl methacrylate, 37 parts of butyl acrylate, 1 of glycidyl methacrylate
Chromic acid 20 parts, phosphoric acid 4 parts per 100 parts of the organic resin obtained by copolymerizing 0 parts, methacrylic acid 20 parts, acrylic acid 3 parts and phosphoric acid group-containing vinyl monomer 0.5 part
An aqueous liquid containing 0 parts was coated with a roll and dried at 160 ° C., and the components were 100 parts of the above organic resin, 20 parts of total Cr in terms of chromic acid, 40 parts of phosphoric acid, and the amount of adhesion was 73 mg / m in terms of Cr. A chromate film of ² was formed. Further thereon, 10 parts of methyl methacrylate, 30 parts of butyl acrylate, 15 parts of glycidyl methacrylate, 25 parts of methacrylic acid, 1 part of acrylic acid.
To 100 parts of an organic resin obtained by copolymerizing 5 parts and 3 parts of a phosphoric acid group-containing vinyl-based monomer, an aqueous liquid containing 25 parts of colloidal silica was applied with a roll and dried at 150 ° C. 100 parts of resin and 25 colloidal silica
An organic composite-plated steel sheet having a coating consisting of 10 parts and 1.3 g / m ² was produced.

Example 25 Zn-Mg based alloy plated steel sheet (Basis weight: 30 g / m ² ,
Mg = 1.0%), 30 parts of methyl methacrylate, 37 parts of butyl acrylate, 10 parts of glycidyl methacrylate
Part, 20 parts of methacrylic acid, 3 parts of acrylic acid, and 100 parts of an organic resin obtained by copolymerizing 0.5 part of a vinyl monomer containing a phosphoric acid group, 20 parts of chromic acid and 40 parts of phosphoric acid
1 part of the above-mentioned organic resin is 100 parts of total Cr is 20 parts of chromic acid equivalent is 40 parts of phosphoric acid, and the adhesion amount is 45 mg / m ² of Cr equivalent. A chromate film was formed. Further, an aqueous solution of vinyl-modified epoxy resin was applied onto it by a roll and dried at 150 ° C. to produce an organic composite plated steel sheet having a film of vinyl-modified epoxy resin of 1.5 g / m ² .

Example 26 Zn-Mn alloy plated steel sheet (Basis weight: 20 g / m ² ,
Mn = 45.3%), 30 parts of methyl methacrylate, 37 parts of butyl acrylate, 1 of glycidyl methacrylate
An aqueous solution containing 100 parts of an organic resin obtained by copolymerizing 0 part, 20 parts of methacrylic acid, 3 parts of acrylic acid and 0.5 part of a vinyl monomer containing a phosphoric acid group, 20 parts of chromic acid, and 40 parts of phosphoric acid. The liquid was applied by a roll and dried at 150 ° C., and the components were 100 parts of the above organic resin, 20 parts of total Cr in terms of chromic acid, 40 parts of phosphoric acid, and a chromate film with an adhesion amount of 38 mg / m ^{2 in} terms of Cr. Formed. Further thereon, an aqueous liquid prepared by mixing 25 parts of colloidal silica with 100 parts of olefin / acrylic acid copolymer resin was coated with a roll and dried at 150 ° C. to obtain 100 parts of olefin / acrylic acid copolymer resin and colloidal silica. An organic composite plated steel sheet having a coating consisting of 25 parts of 1.2 g / m ² was produced.

Example 27 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 11.9%), methyl methacrylate 35 parts, butyl acrylate 32 parts, glycidyl methacrylate 1
Chromic acid 25 parts, phosphoric acid 4 parts per 100 parts of an organic resin obtained by copolymerizing 2 parts, methacrylic acid 25 parts, acrylic acid 5 parts and phosphoric acid group-containing vinyl monomer 1.5 parts
An aqueous liquid containing 5 parts, 15 parts of colloidal silica and 3 parts of MgO was coated on a roll and dried at 150 ° C. to obtain 100 parts of the above organic resin. 25 parts of total Cr in terms of chromic acid 45 parts of phosphoric acid SiO ₂ A chromate film having an adhesion amount of 58 mg / m ^{2 in} terms of Cr was formed with 15 parts of MgO 3 parts. Further, 10 parts of methyl methacrylate, 45 parts of butyl acrylate, 5 parts of glycidyl methacrylate, 15 parts of methacrylic acid, 5 parts of acrylic acid and 1 part of a vinyl group monomer containing a phosphoric acid group were obtained by copolymerization. The aqueous liquid of the obtained organic resin was applied by a roll and dried at 150 ° C. to produce an organic composite-plated steel sheet having a film of 1.1 g / m ² made of the above organic resin.

Example 28 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 13.6%), methyl methacrylate 35 parts, butyl acrylate 32 parts, glycidyl methacrylate 1
3 parts, 25 parts of methacrylic acid, 5 parts of acrylic acid and 100 parts of an organic resin obtained by copolymerizing 0.5 part of a phosphoric acid group-containing vinyl-based monomer, to 25 parts of chromic acid and 3 parts of phosphoric acid.
An aqueous solution containing 5 parts and 10 parts of colloidal silica was applied by a roll and dried at 150 ° C. to obtain 100 parts of the above organic resin, 25 parts of total Cr in terms of chromic acid, 35 parts of phosphoric acid, and 10 parts of SiO ₂ , A chromate film having an adhesion amount of 52 mg / m ^{2 in} terms of Cr was formed. Further thereon, 40 parts of methyl methacrylate, 45 parts of butyl acrylate, 18 parts of glycidyl methacrylate, 25 parts of methacrylic acid, 3 parts of acrylic acid.
Parts and 100 parts of an organic resin obtained by copolymerizing 2 parts of a phosphoric acid group-containing vinyl-based monomer, an aqueous solution containing 20 parts of Aerosil was applied by a roll, and dried at 140 ° C. to obtain the above organic resin. An organic composite plated steel sheet having a coating composed of 100 parts and 20 parts of Aerosil was produced at 1.3 g / m ² .

Example 29 Zn-Cr alloy plated steel sheet (Basis weight: 20 g / m ² ,
Cr = 11.2%), methyl methacrylate 30 parts, butyl acrylate 37 parts, glycidyl methacrylate 1
Chromic acid 20 parts, phosphoric acid 4 parts per 100 parts of the organic resin obtained by copolymerizing 0 parts, methacrylic acid 20 parts, acrylic acid 3 parts and phosphoric acid group-containing vinyl monomer 0.5 part
An aqueous solution containing 0 parts, 10 parts of colloidal silica and 2 parts of MgO was coated on a roll and dried at 140 ° C. to obtain 100 parts of the above organic resin, 20 parts of total Cr in terms of chromic acid, 40 parts of phosphoric acid, 40 parts of SiO ₂ 10 A part of MgO 2 formed a chromate film having an adhesion amount of 40 mg / m ^{2 in} terms of Cr. Further, an aqueous solution of vinyl-modified epoxy ester resin was applied on it by a roll and dried at 150 ° C. to produce an organic composite plated steel sheet having a film of vinyl-modified epoxy ester resin of 1.7 g / m ² .

Example 30 Zn-Ni alloy-plated steel sheet (weight per unit area: 20 g / m ² ,
Ni = 12.0%), methyl methacrylate 30 parts, butyl acrylate 37 parts, glycidyl methacrylate 1
Chromic acid 20 parts, phosphoric acid 4 parts per 100 parts of the organic resin obtained by copolymerizing 0 parts, methacrylic acid 20 parts, acrylic acid 3 parts and phosphoric acid group-containing vinyl monomer 0.5 part
An aqueous solution containing 0 parts and 15 parts of colloidal silica was applied by a roll and dried at 150 ° C. to obtain 100 parts of the above organic resin, 20 parts of total Cr in terms of chromic acid, 40 parts of phosphoric acid, 40 parts of SiO _{2, and} 15 parts of A chromate film having an adhesion amount of 52 mg / m ^{2 in} terms of Cr was formed. Furthermore, 100 parts of the urethane-modified epoxy ester resin and 25 parts of Aerosil were mixed with an aqueous solution by a roll and dried at 150 ° C. to form a coating film consisting of 100 parts of the urethane-modified epoxy ester resin and 25 parts of Aerosil. An organic composite plated steel sheet having 9.9 g / m ² was produced.

Comparative Example 13 A Zn-plated steel sheet was coated with an aqueous solution containing 30 parts of chromic acid and 50 parts of phosphoric acid by a roll and dried at 160 ° C. to form a chromate film having an adhesion amount of 58 mg / m ^{2 in} terms of Cr. did.

Comparative Example 14 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² ,
Ni = 12.3%), chromic acid 25 parts, phosphoric acid 30 parts,
Apply 10 parts of colloidal silica aqueous solution with a roll and
It was dried at 70 ° C. to form a chromate film having an adhesion amount of 45 mg / m ^{2 in} terms of Cr.

Comparative Example 15 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%), to 100 parts of acrylic emulsion, an aqueous solution containing 15 parts of chromic acid and 30 parts of phosphoric acid was applied by a roll and dried at 160 ° C., and the components were acrylic resin 100 parts and total Cr. Chromate conversion: 15 parts Phosphoric acid: 30 parts: A chromate film having an adhesion amount of 75 mg / m ^{2 in} terms of Cr was formed.

Comparative Example 16 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 11.8%), an aqueous solution prepared by mixing 30 parts of chromic acid, 40 parts of phosphoric acid, and 25 parts of Aerosil with 100 parts of acrylamide resin is dried by a roll and dried at 160 ° C. A total of 30 parts by weight of chromium in terms of chromic acid and 40 parts by weight of phosphoric acid and 25 parts by weight of SiO ₂ were applied to form a chromate film having an adhesion amount of 53 mg / m ^{2 in} terms of Cr.

Comparative Example 17 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%) to 100 parts of acrylic amide resin, an aqueous solution containing 15 parts of chromic acid and 50 parts of phosphoric acid is applied by a roll and dried at 150 ° C. to obtain 100 parts of acrylic amide resin. Chromate was converted into chromic acid in 15 parts. Phosphoric acid in 50 parts to form a chromate film having an adhesion amount of 46 mg / m ^{2 in} terms of Cr. Further, an aqueous solution of an epoxy resin was applied onto it by a roll and dried at 150 ° C. to produce an organic composite plated steel sheet having a coating of epoxy resin of 1.3 g / m ² .

Comparative Example 18 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² ,
Ni = 13.1%), an aqueous solution prepared by mixing 25 parts of chromic acid, 25 parts of phosphoric acid, and 20 parts of colloidal silica with 100 parts of an acrylic emulsion was applied by a roll and dried at 150 ° C. A total of 25 parts by weight of chromium in terms of chromic acid and 40 parts by weight of phosphoric acid and 20 parts by weight of SiO ₂ were applied to form a chromate film having an adhesion amount of 52 mg / m ^{2 in} terms of Cr. Further thereon, an aqueous solution prepared by mixing 25 parts of Aerosil with 100 parts of epoxy resin is applied by a roll and dried at 150 ° C. to form a film of 100 parts of epoxy resin and 25 parts of Aerosil at 1.5 g / m 2. An organic composite plated steel sheet having ² was manufactured. Table 3 shows Zn or Zn
Bare alloy corrosion resistance after processing by the salt spray test of Examples 21 to 30 and Comparative Examples 13 to 18 when treated with a base alloy plated steel sheet, a melamine-based low temperature baking type coating (baking temperature: 11
It shows the paint adhesion, Cr elution resistance, fingerprint resistance, and bath stability when 30 μm of (0 ° C.) is applied.

[0083]

[Table 3]

As is clear from Table 3, when the chromate according to the present invention is applied to the Zn-plated steel sheet, bare corrosion resistance after processing hardly changes after 1000 hours, and a little red rust occurs at 1500 hours. There are only a few things. When the chromate according to the present invention is applied to a Zn-based alloy-plated steel sheet, bare corrosion resistance after processing hardly changes after 1500 hours, and only a small amount of red rust is generated at 2000 hours. Further, the bare corrosion resistance after processing in the case of the organic composite plated steel sheet on which the chromate according to the present invention was carried out, and further the organic resin according to the present invention was further carried out, a slight red rust was observed in some samples after 4000 hours. There is only something.

On the other hand, in the case of the known chromate film composition (Comparative Examples 13 and 14), red rust was considerably generated after 100 hours of SST. In addition, resin chromates other than the present invention (comparative examples 15 and 16) to which various resins are added are also 400
A considerable amount of red rust has occurred over time. Further, the adhesion of the coating film is also the same, and in the case of carrying out the present invention, a low temperature baking type (110 ° C. baking), which is difficult to obtain paint adhesion, shows extremely excellent adhesion, but a known chromate film (Comparative Example 1
3, 14) or the resin chromate other than the present invention (Comparative Examples 15 and 16), the paint adhesion is extremely poor. Also in terms of the Cr elution property, when the present invention is carried out, almost no Cr elution occurs. On the other hand, in the case of the known chromate film (Comparative Examples 13 and 14) and the resin chromate other than the present invention (Comparative Examples 15 and 16), a large amount of Cr is eluted.

The resin chromate coatings of the present invention (Examples 21 and 22) have very good fingerprint resistance.
On the other hand, a coated chromate film other than the present invention (Comparative Examples 13 and 14) and a resin chromate film (Comparative Examples 15 and 1)
The fingerprint resistance of 6) is extremely poor, and fingerprints are easily attached. Further, the resin chromate bath according to the present invention (Examples 21 to 3)
The bath life of 0) is extremely long and does not change for a long time. On the other hand, resin chromate baths other than the present invention (Comparative Examples 15 to 1)
The bath life of 8) is extremely short, and the resin gels and becomes unusable in an extremely short time.

[0087]

As described above, the resin chromate treatment bath of the present invention has a very long bath life, and is a chromate film excellent in bare corrosion resistance, paint adhesion and Cr elution resistance after being processed into various metal plates. In addition, the surface-treated steel sheet having a specified amount of the above chromate film of the present invention, the organic composite plated steel sheet shows extremely excellent bare corrosion resistance after processing, and also has excellent adhesion to a coating material, and Cr resistance. It has excellent elution properties,
Further, since fingerprint resistance can be imparted, it can be used as it is after being processed, or it can be used after being coated, which is most suitable as a base for a coated steel sheet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidetoshi Niigatsu, Hidetoshi Niiga, 1 Fuji-machi, Hirohata-ku, Himeji-shi, Hyogo Pref., Hirohata Works, Nippon Steel Co., Ltd. No. 1 Shin Nippon Steel Co., Ltd., Hirohata Works (72) Inventor Kyoko Kizu 3-10-10, Kanaoka Higashi-cho, Okayama City, Okayama Prefecture (72) Inventor Shuji Shibuki 74, Nakatsuka, Okayama City, Okayama Prefecture

Claims (8)

[Claims] 1. At least methacrylic acid among monomers selected from the group consisting of methyl methacrylate, butyl acrylate, glycidyl methacrylate, methacrylic acid, acrylic acid, phosphoric acid group-containing vinyl monomers and hydroxyethyl methacrylate. Chromic acid 5-50 with respect to 100 parts (hereinafter, weight part) of an organic resin obtained by reacting methyl, butyl acrylate, glycidyl methacrylate, methacrylic acid and acrylic acid as essential components
Part and an aqueous liquid containing 10 to 60 parts of phosphoric acid, and a resin chromate bath. 2. Obtained by copolymerizing 5 to 40 parts of methyl methacrylate, 15 to 55 parts of butyl acrylate, 3 to 30 parts of glycidyl methacrylate, 10 to 45 parts of methacrylic acid and 1 to 20 parts of acrylic acid. A resin chromate bath comprising an aqueous liquid in which 5 to 50 parts of chromic acid and 10 to 60 parts of phosphoric acid are mixed with 100 parts of an organic resin used. 3. Methyl methacrylate 1-30 parts, butyl acrylate 20-50 parts, glycidyl methacrylate 3-25 parts, methacrylic acid 10-40 parts, acrylic acid 1-20 parts and hydroxyethyl methacrylate 3
A resin chromate bath comprising an aqueous liquid in which 5 to 50 parts of chromic acid and 10 to 60 parts of phosphoric acid are mixed with 100 parts of an organic resin obtained by copolymerizing 25 to 25 parts. 4. 6 to 40 parts of methyl methacrylate, 25 to 50 parts of butyl acrylate, 3 to 20 parts of glycidyl methacrylate, 10 to 30 parts of methacrylic acid, 1 to 20 parts of acrylic acid and phosphoric acid group-containing vinyl. System monomer 0.0
A resin chromate bath comprising an aqueous liquid in which 5 to 50 parts of chromic acid and 10 to 60 parts of phosphoric acid are mixed with 100 parts of an organic resin obtained by copolymerizing 5 to 5 parts. 5. The resin chromate bath according to claim 1.
And also SiO₂, Cr₂O₃, Fe₂O₃, Fe₃
O_Four, MgO, ZrO₂, SnO₂, Al₂O ₃Zo
Organic resin 10 containing one or more of powder or powder
It should consist of an aqueous liquid containing 5 to 30 parts with respect to 0 parts.
Characteristic resin chromate treatment bath. 6. A chromate film formed from the resin chromate bath according to claim 1 on a cold-rolled steel plate or Zn or Zn-based alloy plated steel plate in terms of Cr of 10 to 300.
A surface-treated steel sheet having mg / m ² . 7. A chromate film formed from the resin chromate treatment bath according to claim 5 is applied to a cold-rolled steel sheet or Zn or Zn-based alloy plated steel sheet in an amount of 10 to 300 in terms of Cr.
A surface-treated steel sheet having mg / m ² . 8. The surface-treated steel sheet according to claim 6 or 7.
Further, one of the following (1) to (4)
A surface-treated steel sheet having a film containing an organic resin. (1) 0.2 to 10 comprising the organic resin according to claims 1 to 4.
3.0 g / m²Film. (2) Si based on 100 parts of the organic resin of (1) above
O₂, Cr₂O₃, Fe₂O ₃, Fe₃O_Four, MgO,
ZrO₂, SnO₂, Al₂O₃, Sol or powder
5 to 30 parts of 1 type or 2 types or more of
0.2-3.0 g / m ² Film. (3) Olefin / acrylic acid copolymer resin, polyac
Lyric acid and its copolymer resin, polyacrylic acid ester
And its copolymer resin, polymethacrylic acid ester and
Its copolymer resin, epoxy resin, acrylic modified epoxy resin
Resin, ester modified epoxy resin, urethane modified epoxy
Xy resin, urethane modified epoxy ester resin, vinyl
Of modified epoxy resin, vinyl modified epoxy ester resin
0.2 to 3.0 g / m consisting of one kind or two or more kinds² 
Film. (4) Olefin / acrylic acid copolymer resin, polyac
Lyric acid and its copolymer resin, polyacrylic acid ester
And its copolymer resin, polymethacrylic acid ester and
Its copolymer resin, epoxy resin, acrylic modified epoxy resin
Resin, ester modified epoxy resin, urethane modified epoxy
Xy resin, urethane modified epoxy ester resin, vinyl
Of modified epoxy resin, vinyl modified epoxy ester resin
100 parts of one or more kinds of resin and SiO₂, Cr
₂O₃, Fe₂O₃, Fe₃O_Four, MgO, ZrO₂,
SnO₂, Al₂O₃, One of sol or powder
0.2 to 3.0 g consisting of 2 or more types of 10 to 60 parts
/ M² Film.