JPH09241856A - Chromium-free composition for surface treatment for metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pollution-free composition for surface treatment for metal, capable of forming a film excellent in adhesion, corrosion resistance, and adhesion of coating material on a metal, by incorporating a hydroxyl-group- containing organic resin, phosphoric acid, and a phosphoric acid-based compound containing metal. SOLUTION: This composition is a chromium-free composition for surface treatment for metal, containing 2-60 pts.wt. of phosphoric acid and 0.015-1.5 parts by gram molecule of a phosphoric acid-based compound containing one or more elements among Cu, Co, Fe, Mn, Sn, V, Mg, Ba, Al, Ca, Sr, Nb, Y, and Zn, based on 100 pts.wt. of a hydroxyl-group-containing organic resin. By using this composition, a film, free from peeling even after immersion in boiling water for 30min and excellent in adhesion, can be formed on a galvanized steel sheet by coating. It is preferable that this organic resin contains a hydroxyl-group-containing monomer component, such as hydroxyethyl (meth) acrylate, by >=5wt.%. Moreover, this composition can further contain colloids (sols) or powders of SiO2 , Cr2 O3 , Fe2 O3 , Fe3 O4 , MgO, ZrO2 , SnO2 , Al2 O3 , and Sb2 O5 , if necessary.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal such as a cold rolled steel sheet, a Zn plated steel sheet, a Zn alloy plated steel sheet, Ni, Cu, P.
b, Sn, Cd, Al, Ti, etc. Metal plate or a plated steel sheet of these metals or an alloy-plated steel sheet of these metals is applied and dried to form an anticorrosive film. The present invention relates to a metal surface treatment composition and a surface-treated metal plate having a rust preventive coating using the same.

[0002]

2. Description of the Related Art Cold rolled steel sheets, Zn plated steel sheets, Zn-Ni series, Zn
-Ni-Co series, Zn-Ni-Cr series, Zn-Fe series, Zn-Co series, Zn-Cr series
System, Zn-based alloy plated steel such as Zn-Mn system, Ni, Cu,
In order to improve the corrosion resistance of a metal plated steel sheet of Pb, Sn, Cd, Al, Ti or the like or an alloy plated steel sheet of these metals, a chromate film is generally formed by a chromate treatment.

However, as a recent tendency, due to environmental and pollution problems, regulations on chromium are being significantly strengthened. Correspondingly, the development of corrosion resistant coating compositions that do not use chromium is being carried out. For example, one that coats an emulsion polymer obtained by polymerizing a polymerizable unsaturated monomer containing a specific amount of unsaturated carboxylic acid (JP-A-5-222324), an aqueous dispersion of a synthetic resin containing a pendant acetoacetyl group. (Japanese Patent Application Laid-Open No. 5-148432), a substantially water-insoluble mono- or poly-basic salt of a special keto acid and a base selected from cations, amines, guanidines, and amidines Coating a mixture of
Gazette), unsaturated carboxylic acid-unsaturated monomer containing glycidyl group-monomer copolymerized with alkyl acrylate-copolymer of alkyl acrylate, coated with resin (JP-A-3-192166) Etc. can be given. All of them are coated with a special resin, but it is necessary to form a considerably thick film in order to ensure corrosion resistance. In addition, the adhesion to various metals such as iron and various plated steel sheets is not necessarily good, and the adhesion is remarkably lowered, especially in a wet environment, and the film peels off. There is no film that can maintain excellent adhesion even when wet.

[0004]

On the other hand, the present invention solves the above-mentioned drawbacks of the prior art, cold rolled steel sheet or Zn or Zn-based alloy plated steel sheet, Ni, Cu, Pb, Sn, Cd, Al, Even if a very thin film is formed on a metal plate such as Ti or a plated steel plate of these metals or an alloy-plated steel plate of these metals, it shows excellent adhesion to the material, and has extremely excellent corrosion resistance and paint adhesion. The first object is to provide a chromium-free surface treatment agent that can be secured. The second purpose is cold rolled steel or Zn or Zn alloy plated steel, Ni, C
u, Pb, Sn, Cd, Al, Ti or other metal plate or a plated steel sheet of these metals or an alloy-plated steel sheet of these metals, by the above treatment agent, a bare corrosion resistance after processing, a film excellent in paint adhesion It is intended to provide a chromium-free surface treatment agent which is excellent in bare corrosion resistance and coating adhesion after processing to form a specific amount.

[0005]

[Means for Solving the Problems] That is, the present invention relates to a hydroxyl group-containing organic resin, phosphoric acid and Cu, Co, Fe, Mn, Sn, V, M.
A composition containing a phosphoric acid compound containing at least one metal selected from g, Ba, Al, Ca, Sr, Nb, Y and Zn, the composition forming a film having the following characteristics (1): A chrome-free metal surface-treating composition that can be used. (1) A film formed by applying the composition on a Zn-plated steel sheet does not peel off even after being immersed in boiling water for 30 minutes. In the present invention, a special organic resin, phosphoric acid, a surface treatment solution containing a phosphoric acid compound of a special element as a component, or a surface treatment agent containing a special inorganic substance is a cold rolled steel sheet or
Ensures excellent adhesion to various metals by applying it to various metals including Zn or Zn alloy plated steel sheets,
It is possible to form a surface-treated film having excellent bare corrosion resistance after processing and also excellent adhesion to various organic resins. This extremely excellent adhesion to various metals is ensured by combining a special organic resin with phosphoric acid and a phosphoric acid compound of a special element. Further, extremely excellent bare corrosion resistance can be realized only by combining a special organic resin and a phosphoric acid compound of a special element. Also, excellent paint adhesion is ensured by combining a special organic resin with phosphoric acid and a phosphoric acid compound of a special element. Hereinafter, the contents of the special organic resin and the phosphoric acid compound of the special element and the special organic resin used in the present invention,
It shows how the characteristics of the film formed by the combination of phosphoric acid and a phosphoric acid compound of a special element change.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The hydroxyl group-containing organic resin in the present invention means an organic resin containing a hydroxyl group-containing monomer as a copolymerization component in an amount of 5% by weight or more (hereinafter referred to as the present organic resin). In the following description, "%" means "wt%" and "parts" means "parts by weight". Examples of the hydroxyl group-containing monomer component include (meth) acrylic acid-hydroxyl ethyl,
Hydroxypropyl (meth) acrylate, -3-hydroxybutyl (meth) acrylate, 2,2-bis (hydroxymethyl) ethyl acrylate, (meth) acrylic acid-2,3
-(Meth) acrylic acid hydroxyesters such as dihydroxypropyl and (meth) acrylic acid-3-chloro-2-hydroxypropyl, allyl alcohols and alcohol amides such as N-methylolacrylamide and N-butoxymethylol (meth) acrylamide Glycidyl (meth) acrylate, allyl glycidyl ether, β-methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl ( Meta)
Although a monomer having a glycidyl group such as acrylate and a monomer having an aldehyde group of acroleinamide can be used, -2-hydroxyethyl acrylate and -2-hydroxyethyl methacrylate are particularly preferable. In addition, (meth) acrylic acid-is methacrylic acid-and /
Or represents acrylic acid.

The present organic resin is the above-mentioned hydroxyl group-containing monomer alone or is copolymerized with the above-mentioned hydroxyl group-containing monomer so that the amount of the hydroxyl group-containing monomer is 5% or more (hereinafter sometimes referred to simply as containing). ) Says resin. As the other organic resin, it is desirable to use any one or two of ethylenically unsaturated carboxylic acid and other ethylenically unsaturated compounds at the same time. As the ethylenically unsaturated carboxylic acid component, for example, acrylic acid, methacrylic acid, ethylenically unsaturated monocarboxylic acid such as crotonic acid, itaconic acid, maleic acid, ethylenically unsaturated dicarboxylic acid such as fumaric acid, and those Alkali metal salts of carboxylic acids, ammonium salts and organic amine salts can be used. Further, the ethylenically unsaturated compound is an ethylenically unsaturated compound other than the examples of the ethylenically unsaturated carboxylic acid component and the hydroxyl group-containing monomer component, and the (meth) acrylic acid alkyl ester and its copolymer resin, and other Vinyl compounds such as aromatic vinyl compounds. In addition to the above, polyacrylic acid ester and its copolymer resin, polymethacrylic acid ester and its copolymer resin, epoxy and its copolymer resin, acrylic modified epoxy and its copolymer resin, ester modified epoxy and its copolymer It is also possible to use a coalescing resin, a urethane-modified epoxy resin and a copolymer resin thereof. One or two or more selected from these can be used in combination. Further, compounds other than the above-mentioned compounds may be contained within the range not impairing the object of the present invention.

Special element phosphoric acid compounds are Cu, Co,
It means a phosphoric acid compound of Fe, Mn, Sn, V 2, Mg, Ba, Al, Ca, Sr, Nb, Y and Zn. It is preferable that one or more of the phosphoric acid compounds of these special elements are blended in the amount of 0.015 to 1.5 gram molecular part. Further, it is preferable to mix 100 parts by weight of the present organic resin containing the hydroxyl group-containing monomer as a main component with 2 to 60 parts by weight of phosphoric acid.

Hereinafter, a bath in which the present organic resin, a phosphoric acid compound of a special element, and phosphoric acid coexist is prepared, and a film is formed on a plated steel sheet to show how the characteristics change. As the organic resin, a resin prepared by copolymerizing 50 parts of hydroxyethyl acrylate (hydroxyl group-containing monomer) -20 parts of methyl methacrylate-20 parts of acrylic acid (hydroxyl group-containing monomer: 59%) is used.
100 g / l (solid content) (100 parts by weight) was added. Also, 15 g / l (15 parts by weight) of phosphoric acid was added, and various compounds of Mn (Mn chloride, Mn sulfate, Mn nitrate, Mn acetate, Mn phosphate, Mn hydroxide, Mn hydroxide,
Oxidized Mn) was added in various proportions. A surface treatment bath consisting of these aqueous liquids was prepared, and the electric Zn plated steel sheet (Zn
Adhesion amount: 30 g / m ² ) applied so that the total solid content is 0.45 g / m ^2, and dried to form a film.
It was investigated how the adhesiveness with the Zn-plated steel sheet), the adhesiveness with the paint, and the bare corrosion resistance after processing changed.

Here, the adhesion between the material and the surface-treated film according to the present invention is determined by immersing the film in boiling water for 30 minutes after drying, and then cutting the film on a 2 mm slot and peeling the tape to remove the coating film. Was evaluated. ◎: Film peeling area 0% ○: 〃 more than 0% to 1% △: 〃 more than 1% to 10% ×: 〃 more than 10% to 50% XX: more than 50%

Adhesion with the paint was sprayed with a melamine-based low-temperature baking paint (baking temperature: 110 ° C.) on the surface-treated film obtained, and then spray-painted to 30 μm, then immersed in boiling water for 30 minutes, After that, the coating film was cut on a 2 mm edge and the tape was peeled off to evaluate the peeled area of the coating film. ◎: Coating peeling area 0% ○: 〃 more than 0% to 1% △: 〃 more than 1% to 10% ×: 〃 more than 10% to 50% XX: more than 50%

The 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, and the occurrence of red rust on the side surface subjected to the ironing process. Corrosion test is JI
By salt spray test based on SZ-2371 standard (salt water concentration
5%, bath temperature 35 ° C, spraying pressure 20PSI) Shows the rusting status after 1000 hours, and evaluates it in five stages of ◎, ○, △, ×, XX.
Is the best. ◎: Red rust occurrence rate 0% ○: 〃 more than 0% to 1% △: 〃 more than 1% to 10% ×: 〃 more than 10% to 50% × ×: more than 50%

The adhesion of the formed film to the Zn-plated steel sheet greatly differs depending on the type of compound added and the amount added, and in the liquid containing Mn chloride, Mn sulfate, Mn nitrate, Mn acetate, Mn hydroxide and Mn oxide, In all cases, excellent adhesion was not obtained even if the amount added was changed. On the other hand, the film formed from the solution containing Mn phosphate has excellent adhesion to the Zn-plated steel sheet, and especially Mn phosphate is 0.015 g molecule / l.
(Parts) or more and 1.5 gram molecules / l (parts) or less, extremely excellent adhesion is obtained, and the peeled area of the film is none (⊚) in the above test. Mn phosphate 0.015 g molecule / l
If it is less than (parts) or more than 1.5 gram molecule / l (parts), the adhesion will decrease. In addition, the adhesion of the formed film to the coating material varies greatly depending on the type of compound added and the amount added, and any of the solutions added with Mn chloride, Mn sulfate, Mn nitrate, Mn acetate, Mn hydroxide and Mn oxide added. Even if the amount was changed, excellent paint adhesion was not obtained. In contrast, Mn phosphate
The film formed from the liquid containing the additive shows excellent paint adhesion, and Mn phosphate is 0.015 gram molecule / l (part) or more, 1.5
When it is less than gram molecule / l (part), particularly excellent paint adhesion is exhibited, and the peeled area of the coating film is none (⊚) in the above test. If it is less than 0.015 gram molecule / l (part) or more than 1.5 gram molecule / l (part), the coating adhesion will decrease. The bare corrosion resistance of the formed film after processing greatly differs depending on the type of compound added and the amount added, and the amount added for all solutions containing Mn chloride, Mn sulfate, Mn nitrate, Mn acetate, Mn hydroxide and Mn oxide was Even if changed, excellent bare corrosion resistance after processing was not obtained. On the other hand, the film formed from the solution containing Mn phosphate showed excellent bare corrosion resistance after processing, and Mn phosphate was 0.
015 gram molecule / l (part) or more, 1.5 gram molecule / l (part)
The following shows particularly excellent bare corrosion resistance after processing, and there is no occurrence of red rust (⊚) in the above test. 0.015 gram molecule
Less than / l (part) and more than 1.5 gram molecule / l (part) reduce bare corrosion resistance after processing.

Next, as the present organic resin, resins in which hydroxyethyl acrylate (hydroxyl group-containing monomer) was variously changed were prepared, and hydroxyethyl acrylate (hydroxyl group-containing monomer) α part-methyl methacrylate 20 parts-acrylic acid
35 g of a copolymerized resin) was added at 100 g / l (solid content) (100 parts by weight). Further, 15 g / l (15 parts by weight) of phosphoric acid was added, and 0.35 g molecule / l (part) of phosphoric acid Mn was further added to prepare an aqueous liquid. A surface treatment bath consisting of these aqueous liquids was applied to an electric Zn-plated steel sheet (Zn adhesion amount: 30 g / m ² ) so that the total solid content was
About the coating when it is applied to 0.40 g / m ² and dried, the adhesion with the material (electrical Zn plated steel sheet),
It was investigated how paint adhesion and bare corrosion resistance after processing change.

The proportion of the hydroxyl group monomer in the present organic resin affects the adhesion between the formed film and the electric Zn-plated steel sheet, and improves when it exceeds 5% (⊚). The proportion of the hydroxyl group monomer in the present organic resin affects the paint adhesion, and when it is 5% or more, the paint adhesion is remarkably improved, and no coating film peeling occurs in the above test (⊚). If it is less than 5%, the adhesiveness of the paint will be reduced. In addition, the proportion of hydroxyl monomer in this organic resin has a great influence on the bare corrosion resistance of the processed part,
As a result, the bare corrosion resistance of the worked part is significantly improved (⊚), and if it is less than 5%, the bare corrosion resistance of the worked part is reduced.

Next, as the organic resin, 100 g / l of a resin obtained by copolymerizing 15 parts of hydroxyethyl acrylate (hydroxyl group-containing monomer) -35 parts of methyl methacrylate-30 parts of acrylic acid (hydroxyl group-containing monomer: 19%) (Solid content) (100 parts by weight), 0.15 gram molecule / l (part) of Mn phosphate was added, and phosphoric acid was added at various ratios. A surface treatment bath consisting of these aqueous liquids was prepared, and the electric Zn plated steel sheet (Zn
Adhesion: 30 g / m ² ) applied so that the total solid content is 0.42 g / m ^2, and the film formed when dried is adhered to the material (electrical Zn-plated steel sheet), paint adhesion and It was investigated how the bare corrosion resistance changes after processing. The concentration of phosphoric acid has a great influence on the adhesion between the formed film and the electric Zn plated steel sheet, and shows excellent adhesion at 2 to 60 parts by weight relative to 100 parts by weight of this organic resin. Is none (◎). If the amount is less than 2 parts by weight or more than 60 parts by weight, the adhesion of the coating is deteriorated. The concentration of phosphoric acid influences the adhesiveness of the paint, showing excellent adhesiveness at 60 parts by weight or less, and there is no peeling of the coating film in the above test (⊚). If it exceeds 60 parts by weight, the adhesiveness of the paint will be reduced. Further, the concentration of phosphoric acid does not significantly affect the corrosion resistance of the processed part. If it exceeds 60 parts by weight, the corrosion resistance of the processed part will be slightly reduced. The phosphoric acid referred to in the present invention is not limited as long as it becomes phosphoric acid in the bath, and in addition to phosphoric acid, for example, polyphosphoric acid, hypophosphorous acid, tripolyphosphoric acid, hexametaphosphoric acid, primary phosphoric acid, Diphosphoric acid, tertiary phosphoric acid,
It means a phosphoric acid compound such as polymetaphosphoric acid or polyphosphoric acid.

From the above results, 5% of the hydroxyl group-containing monomer was added.
With respect to 100 parts by weight of the organic resin contained above, Mn phosphate of 0.
Add 015 to 1.5 grams molecular part and 2 to 60 parts by weight phosphoric acid
By applying the prepared aqueous liquid to the plated steel sheet,
Excellent adhesion to the board, paint adhesion and resistance to bare parts
It is possible to form a film with extremely excellent corrosion resistance. here
100% organic resin containing 5% or more of hydroxyl group-containing monomer
2 to 60 parts by weight of phosphoric acid is added to each part by weight.
Only when adding a phosphoric acid compound among Mn compounds
Excellent adhesion to coated steel sheets, and paint adhesion and processing
The part that can form a film with extremely excellent corrosion resistance
The reason is not clear enough, but it can be thought as follows.
Generally, Mn chloride, Mn sulfate, Mn nitrate, Mn acetate, etc. are water-soluble.
MnCl when inorganic acid coexists in liquid_Two → Mn⁺⁺ 2Cl^- , MnSO
_Four → Mn⁺⁺SO_Four ^-, Mn (NO_Three)_Two→ Mn⁺⁺2NO_Three ^- , Mn (CH _ThreeCOO)_Two 
→ Mn⁺⁺2CH_ThreeCOO^- It dissolves well and becomes ionized.
After dissolution of these compounds, MnCl_Two Then Mn⁺⁺To Cl^- But MnSO
_Four Then Mn⁺⁺To SO_Four ^-However, Mn (NO_Three)_TwoThen NO in Mn ++_Three ^- But M
n (CH_ThreeCOO)_Two Then Mn⁺⁺To CH_ThreeCOO^- Is coordinated. Coordinate
Strength is PO_Four ^3- <NO_Three ^- <Cl^- <SO_Four ^-<CH_ThreeCOO^- (strength
Yes) and PO_Four ^3-Is extremely weakly coordinated, whereas NO
_Three ^- , Cl^- , SO_Four ^-, CH_ThreeCOO^- Coordinate fairly strongly.
Here, when an organic resin containing a hydroxyl group coexists, Mn⁺⁺
Oxidizes the OH group, Mn⁺⁺→ Become Mn and play the role of bridge
As a result, it forms a dense film. On the other hand, NO_Three ^- ,
Cl^- , SO_Four ^-, CH_ThreeCOO^- And so on, these ions
Due to the strong coordination of the⁺⁺
Makes it difficult to oxidize the OH groups. In other words, Mn chloride, sulfur
Mn when acid Mn, nitric acid Mn and acetic acid Mn are added⁺⁺Is a bridge
It has no function as an agent.

On the other hand, in the case of Mn phosphate, PO for Mn ⁺⁺
_{Since the 4} ^3- coordination is extremely weak, Mn ⁺⁺ has a function of oxidizing the OH group. That is, it has a function as a crosslinking agent. Also, Mn
⁺⁺ The PO ₄ ^3- were weakly coordinated to appear to have a catalytic function of Mn ⁺⁺ promotes oxidation of OH groups. The newly added phosphoric acid seems to be necessary for proper PO ₄ ³⁻ coordination. However, chloride Mn, sulfuric Mn, nitric Mn and NO in the case of acetic acid _{^{Mn 3 -, Cl -, SO}} 4 -, CH 3 COO - coordination for strong
PO ₄ even ³ is coexist, NO coordinated ₃ ^-, Cl ^-, S
O ₄ ^-, CH ₃ COO ^- and it is not the PO ₄ ^3- is replaced, therefore, PO ₄ ^3- can not play a catalytic function. That is, when a hydroxyl group-containing organic resin, an aqueous solution in which phosphoric acid Mn and phosphoric acid are coexisted, and dried to form a film, Mn ⁺⁺
Mn ⁺⁺ oxidizes the OH group of the hydroxyl group-containing monomer due to the catalytic action of PO ₄ ^3- which is weakly coordinated to the OH group, and itself plays the role of crosslinking between resin molecules, resulting in an extremely dense film after film formation. Seem to form. It is considered that the newly formed dense film further strengthens the adhesive force between the material and the film and ensures extremely excellent corrosion resistance. Also,
It is considered that excellent paint adhesion is secured by the synergistic effect of the OH groups remaining without being oxidized by Mn ⁺⁺ and phosphoric acid. In the case of Mn hydroxide and Mn oxide, even the inorganic acid is hardly dissolved and only a very small amount of Mn ⁺⁺ ion is formed, so that the above function cannot be achieved.

The above results show that Mn phosphate is used as the phosphate compound.
I wrote about. Almost the same results can be obtained with any phosphoric acid compound. For example, instead of phosphoric acid, Mn compounds such as polyphosphoric acid, hypophosphorous acid, tripolyphosphoric acid, hexametaphosphoric acid, primary phosphoric acid, secondary phosphoric acid, tertiary phosphoric acid, polymetaphosphoric acid and polyphosphoric acid may be used. As a result of further studies by the present inventors, elements other than Mn such as Cu and C
For o, Fe, Sn, V, Mg, Ba, Al, Ca, Sr, Nb, Y and Zn, when phosphoric acid compounds of these elements, phosphoric acid and hydroxyl group-containing organic resin coexist, the same as in the case of Mn. , The ions of these elements oxidize the hydroxyl groups of the resin with the help of the catalytic function that oxidizes the resin of the phosphate group, which is weakly coordinated around the ions of these elements, and forms a very dense film by itself becoming a cross-linking agent. I found out that In addition, the formed film has excellent adhesion to the material, excellent adhesion to the coating material, and extremely excellent bare corrosion resistance after processing.

From the above results, in the present invention, 2 to 60 parts by weight of phosphoric acid is added to 100 parts by weight of an organic resin containing 5% or more of a hydroxyl group-containing monomer, and Cu, Co, Fe, Mn and S are added.
Surface treatment composition characterized by compounding 0.015 to 1.5 g molecular part of one or more of n, V, Mg, Ba, Al, Ca, Sr, Nb, Y and Zn as a phosphoric acid compound. .

Next, 25 parts of hydroxyethyl acrylate-
Methyl methacrylate 30 parts-Butyl acrylate 20 parts-Methacrylic acid 25 parts (hydroxyl group-containing monomer: 25%) copolymer resin 100 parts by weight (67 g / l), phosphoric acid 15 parts by weight (10 g /
l), Mn phosphate 0.4 g molecule part (0.27 g molecule / l)
A solution containing colloidal silica mixed in various proportions in the mixed aqueous liquid is formed on an electric Zn-plated steel sheet with a basis weight of 30 g / m ² so that the film after drying is 0.42 g / m ^2, and the plating layer and film Adhesion, paint adhesion and bare corrosion resistance after processing were investigated. Here, the evaluation method of the adhesion between the plating layer and the film and the adhesion of the paint is the same as the above, but the bare corrosion resistance after processing is
In the salt spray test according to JIS-2371, the rusting condition after 2000 hours was evaluated. The evaluation criteria are the same as above. If more than 30 parts of colloidal silica is added, the adhesion between the plating layer and the coating will be reduced. When the colloidal silica is 3 to 30 parts, the bare corrosion resistance is further improved after processing. Also, colloidal silica
If it exceeds 30 parts, the paint adhesion tends to decrease. This tendency is that instead of colloidal silica, SiO ₂ powder or Sn
O ₂ , Cr ₂ O ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , MgO, Al ₂ O ₃ or ZrO
Almost the same result was obtained even when ₂ colloids (sols) or powders were blended. In addition, almost the same result was obtained by mixing two or more of these.

Therefore, in the present invention, the hydroxyl group-containing monomer is 5%.
2 to 100 parts by weight of the organic resin contained above
60 parts by weight and Cu, Co, Fe, Mn, Sn, V, Mg,
One or more of Ba, Al, Ca, Sr, Nb, Y, and Zn are mixed as 0.015 to 1.5 gram molecular part as a phosphoric acid compound, and further SiO ₂ , Cr ₂ O ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , MgO, Zr
A surface treatment composition is characterized by containing 3 to 30 parts by weight of one or more colloids (sols) or powders of O ₂ , SnO ₂ , Al ₂ O ₃ , and Sb ₂ O ₅ .

Hydroxyethyl acrylate 35 parts-methyl methacrylate 15 parts-butyl acrylate 25 parts-methacrylic acid 25 parts (hydroxyl group-containing monomer: 35%) 100 parts by weight (60 g / l) of a copolymer resin, A film with 25 parts of phosphoric acid (15 g / l) and 0.5 g of Mn phosphoric acid molecule part (0.3 g molecule / l) mixed in various amounts on an electro-Zn plated steel sheet with a basis weight of 30 g / m ^2. Was formed, and the adhesion between the material and the film, the adhesion of the paint, and the bare corrosion resistance after processing were investigated. The evaluation method of the adhesion between the material and the film and the adhesion of the coating is the same as the above. The bare corrosion resistance after processing was evaluated by a salt spray test in the rusted state after 1500 hours. The evaluation criteria are the same as above. As a result, at 0.1 g / m ² or more, excellent film adhesion to materials, paint adhesion, and bare corrosion resistance after processing were exhibited. Also, when colloidal silica was added to the above-mentioned bath, 0.1 g / m ² or more showed excellent film adhesion to a material, paint adhesion, and bare corrosion resistance after processing. As a result, the coating amount of the surface treatment composition in the present invention is 0.1 g / m ² or more, and the upper limit is 3.0 g / m ² from the economical viewpoint.

The present invention has so far mainly described the case of treating an electric Zn plated steel sheet. However, the present invention
In addition to coated steel sheets, cold rolled steel sheets, hot-dip Zn coated steel sheets and Zn
-Ni system, Zn-Ni-Co system, Zn-Ni-Cr system, Zn-Fe system, Zn-Co
It can be used for electrical or hot-dip Zn alloy-plated steel sheets such as Zn-Cr alloys, Zn-Cr alloys, Zn-Mn alloys, Zn-Al alloys, and Zn-Mg alloys. Also, metal plates such as Ni, Cu, Pb, Cd, Sn, Al and Ti,
Alternatively, it can be used for a plated steel plate made of these metals or alloys of these metals. Further, in order to apply the surface treatment agent according to the present invention to various plated steel sheets, any coating method such as roll coating, spray coating, brush coating, dip coating and curtain flow may be used.

As described above, the surface treatment agent according to the present invention should be used as a substitute for so-called chromate agents such as coating chromate, electrolytic chromate, resin chromate and reaction chromate which are conventionally used as chromium-free surface treatment agents which do not use chromium. Since it is a non-polluting surface treatment agent that does not use chromium, its application is expected to expand greatly for containers and toys.

Hereinafter, examples will be described in detail. Example 1 1-hydroxybutyl acrylate 35 parts-methyl acrylate 20 parts-butyl acrylate 30 parts-styrene 40 parts-methacrylic acid 20 parts-acryl on a Zn-plated steel sheet (weight per unit area: 20 g / m ² ). Acid 5 parts-Copolymer resin of organic phosphorus monomer 1 part (hydroxyl group-containing monomer: 23%) 60 g / l, phosphoric acid 15 g / l, phosphoric acid Cu (Cu: divalent) 0.20 gram molecule / l The coated aqueous solution is applied with a roll and dried at 130 ° C, and the total adhesion amount is 0.30.
A film was formed so as to have g / m ² .

Example 2 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 11.5%)
2-bis (hydroxymethyl) ethyl 10 parts-Methyl methacrylate 30 parts-Butyl acrylate 50 parts-Glycidyl methacrylate 10 parts-Methacrylic acid 20 parts-Acrylic acid 10 parts-Organic phosphorus monomer 1 part Combined resin (monomer containing hydroxyl group: 8%) 80g / l, phosphoric acid 20g / l, phosphoric acid Co
An aqueous liquid containing 0.32 gram molecule / l and 6 g / l of colloidal silica was applied on a roll and dried at 135 ° C to give a total adhesion amount.
A film was formed so that the amount was 0.40 g / m ² .

Example 3 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 12.3%)
Methacrylic acid-2,3-dihydroxypropyl 60 parts-Methyl methacrylate 25 parts-Butyl acrylate 40 parts-Glycidyl methacrylate 25 parts-Methacrylic acid 30 parts-Acrylic acid 10 parts-Organophosphorus monomer 1 part Copolymer resin (hydroxyl group-containing monomer: 31%) 60g / l, phosphoric acid 15g / l, primary Fe (Fe: divalent) phosphate 1.15g molecule / l An aqueous solution is mixed and applied at 75 ° C. And dried to form a film so that the total amount of adhesion would be 0.28 g / m ² .

Example 4 Zn-Fe alloy plated steel sheet (Basis weight: 20 g / m ² , Fe = 12.8%)
Acrylic acid hydroxy ester 90 parts-Methyl methacrylate 50 parts-Butyl acrylate 15 parts-Styrene 20 parts-
Glycidyl methacrylate 25 parts-20 parts methacrylic acid
-Acrylic acid 10 parts-Copolymer resin of organic phosphorus monomer 1 part (hydroxyl group-containing monomer: 39%) 60 g / l, phosphoric acid 12 g / l
, Mn phosphate 0.6 g molecule / l, colloidal silica 20 g /
An aqueous solution containing 1 l was applied on a roll and dried at 110 ° C. to form a film so that the total amount of adhesion was 0.30 g / m ² .

Example 5 Zn-Mg based alloy plated steel sheet (Basis weight: 30 g / m ² , Mg = 1.2%)
N-methylol acrylamide 30 parts-Methyl methacrylate 20 parts-Butyl acrylate 35 parts-Styrene 10 parts-Glycidyl methacrylate 25 parts-Methacrylic acid 40 parts-Acrylic acid 20 parts Copolymer resin (hydroxyl-containing monomer : 17
%) 60 g / l, phosphoric acid 10 g / l, Sn (Sn: divalent) phosphoric acid 0.2 g molecule / l blended aqueous solution with a roll and dried at 170 ° C to give a total adhesion of 0.85 g / l. A film was formed so that the thickness was m ² .

Example 6 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 12.4%)
Allyl glycidyl ether 80 parts-Methyl methacrylate 15 parts-Butyl acrylate 35 parts-Glycidyl methacrylate 10 parts-Methacrylic acid 35 parts-Acrylic acid 10 parts-Hydroxyethyl acrylate 10 parts Copolymer resin (containing hydroxyl groups Monomer: 41%) 80 g / l, phosphoric acid 15 g / l, phosphoric acid V
Apply an aqueous solution containing 1.4 gram molecules / l on a roll,
The film was dried at 90 ° C. to form a film so that the total adhered amount was 1.05 g / m ² .

Example 7 Zn-Mg based alloy plated steel sheet (Basis weight: 30 g / m ² , Mg = 1.2%)
Glycidyl methacrylate 25 parts-Ethyl methacrylate 25 parts-Butyl acrylate 30 parts-Methacrylic acid 40 parts
-Hydroxyethyl acrylate 15 parts copolymer resin (hydroxyl group-containing monomer: 30%) 180 g / l, phosphoric acid 25 g / l,
Phosphate Mg 0.38 g molecule / l, colloidal silica 15 g /
l, MgO 2g / l blended aqueous solution with a roll,
It was dried at ℃ and a film was formed so that the total amount of adhesion would be 0.55 g / m ² .

Example 8 Zn-Ni alloy plated steel sheet (Basis weight: 30 g / m ² , Ni = 13.9%)
Glycidyl methacrylate 15 parts-Ethyl methacrylate 60 parts-Butyl acrylate 40 parts-Methacrylic acid 50 parts
-Organic resin obtained by copolymerizing 35 parts of acrylic acid (hydroxyl group-containing monomer: 8%) 60 g / l, phosphoric acid 15 g / l, phosphoric acid Ba
0.8 gram molecule / l, colloidal silica 15g / l, MgO 1g / l
The aqueous solution containing the above was applied by a roll and dried at 100 ° C. to form a film so that the total amount of the adhering was 0.75 g / m ² .

Example 9 Zn-Cr alloy-plated steel sheet (basis weight: 20 g / m ² , Cr = 10.8%)
Methacrylic acid-3-chloro-2-hydroxypropyl 35
Part-methyl methacrylate 25 parts-butyl acrylate 30 parts
-25 parts of glycidyl methacrylate- Organic resin obtained by copolymerizing 50 parts of acrylic acid (hydroxyl group-containing monomer: 36
%) 75g / l, phosphoric acid 15g / l, phosphoric acid Al 0.7g molecule /
l, colloidal silica 6g / l, MgO 0.5g / l blended aqueous solution was coated with a roll and dried at 110 ℃ to give a total adhesion of 0.45g.
The film was formed so that it would be / m ² .

Example 10 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 12.1%)
To N-butoxymethylol methacrylamide 40 parts-methyl methacrylate 20 parts-butyl acrylate 55 parts-methacrylic acid 35 parts-acrylic acid 10 parts-hydroxyethyl acrylate 30 parts organic resin obtained by copolymerization ( Hydroxyl group-containing monomer: 37%) 100 g / l, phosphoric acid 25 g / l, Ca phosphate
An aqueous solution containing 0.20 gram molecule / l and 25 g / l of colloidal silica was applied on a roll and dried at 80 ° C to give a total adhesion amount.
A film was formed so that the amount would be 0.50 g / m ² .

Example 11 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 12.1%)
Allyl glycidyl ether 45 parts-Methyl methacrylate 30 parts-Butyl acrylate 40 parts-Methacrylic acid 10 parts-
Organic resin obtained by copolymerizing 35 parts of hydroxyethyl acrylate (monomer containing hydroxyl group: 50%) 80 g / l, phosphoric acid
Apply an aqueous solution containing 15 g / l, Sr 0.75 gram molecule / l phosphoric acid, and 20 g / l colloidal silica on a roll and dry at 115 ° C to form a film with a total coverage of 0.75 g / m ^2. Formed.

Example 12 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 12.1%)
Β-Methylglycidyl acrylate 50 parts-Styrene 40
Part-Butyl acrylate 50 parts-Hydroxyethyl acrylate 15 parts-Organic resin obtained by copolymerizing 25 parts methacrylic acid (hydroxyl group-containing monomer: 36%) 90 g / l, phosphoric acid 25 g /
l, an aqueous solution containing 0.05 g of Nb (Nb: trivalent) phosphate molecule / l and 10 g / l of colloidal silica was coated with a roll and
It was dried at 00 ° C to form a film so that the total amount of coating was 0.45 g / m ² .

Example 13 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 12.8%)
55 parts of 3,4-epoxycyclohexyl methacrylate
Methyl methacrylate 40 parts-Butyl acrylate 40 parts-Styrene 40 parts-Methacrylic acid 20 parts-Hydroxyethyl acrylate 20 parts Organic resin obtained by copolymerization (hydroxyl group-containing monomer: 35%) 75 g / l, Phosphoric acid 15 g / l, phosphoric acid Y 0.
An aqueous liquid containing 15 g molecule / l and 9 g / l colloidal silica was applied on a roll and dried at 85 ° C to give a total adhesion of 0.40.
A film was formed so as to have g / m ² .

Example 14 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 13.2%)
Acrylic acid-2-hydroxyethyl 40 parts-butyl acrylate 50 parts-methacrylic acid 35 parts-hydroxyethyl acrylate 35 parts obtained by copolymerizing an organic resin (hydroxyl group-containing monomer: 47%) 90 g / l, Phosphoric acid 30g / l, phosphoric acid Zn 0.3
An aqueous solution containing 7 g molecule / l and 6 g / l of colloidal silica was coated on a roll and dried at 115 ° C to give a total adhesion of 0.
A film was formed so as to have a concentration of 40 g / m ² .

Comparative Example 1 Chromic acid (hexavalent Cr 100% chromic acid) 15 g / l on a Zn-plated steel sheet,
An aqueous solution containing 10 g / l of phosphoric acid was applied by a roll and dried at 175 ° C. to form a chromate film having an adhesion amount of 45 mg / m ^{2 in} terms of Cr.

Comparative Example 2 Zn-Ni alloy plated steel sheet (Basis weight: 20 g / m ² , Ni = 12.8%)
Chromic acid (hexavalent Cr 100% chromic acid) 15g / l, phosphoric acid 15g / l,
Roll with a 5 g / l colloidal silica aqueous solution,
It was dried at 5 ° C to form a chromate film with an adhesion amount of 57 mg / m ^{2 in} terms of Cr.

Comparative Example 3 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² , Ni = 12.9%)
Chromic acid (hexavalent Cr 100% chromic acid) 20 g / l, phosphoric acid 30 g / l,
An aqueous solution containing 80 g / l of an acrylic emulsion (hydroxyl group content: 0%) was coated on a roll and dried at 180 ° C. to form a chromate film with an adhesion amount of 48 mg / m ^{2 in} terms of Cr.

Comparative Example 4 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² , Ni = 12.3%)
Chromic acid (hexavalent Cr 100% chromic acid) 25g / l, phosphoric acid 15g / l,
An aqueous solution containing 60 g / l of an acrylic amide resin was applied by a roll and dried at 130 ° C. to form a film so that the total amount of adhesion was 0.55 g / m ² .

Comparative Example 5 Zn-Ni alloy plated steel sheet (adhesion amount: 20 g / m ² , Ni = 12.9%)
Chromic acid (trivalent Cr / (trivalent Cr + hexavalent Cr) x 100 = 30 (%)) 25 g /
l, phosphoric acid 10g / l, acrylic emulsion 60g / l, colloidal silica 15g / l
It was dried at 175 ° C to form a film so that the total amount deposited would be 0.65 g / m ² .

[0045]

[Table 1]

[0046]

[Table 2]

Table 1 shows the adhesion of the coatings after immersion in boiling water for 30 minutes in Examples 1 to 14 and Table 2 after treating Zn or Zn-based alloy plated steel sheets, and Table 2 after processing by salt spray test. Bare corrosion resistance, low temperature melamine baking type (baking temperature: 110
It shows the adhesiveness of the coating when 30 μC is applied. As is clear from Table 1, Zn-plated steel sheet or Zn
When the surface treatment according to the present invention is performed on the base alloy-plated steel sheet, the formed film has good adhesion and no peeling. The bare corrosion resistance after processing when the surface treatment according to the present invention was carried out on the Zn-plated steel sheet was almost unchanged after 1000 hours.
Slight red rust occurs over time. When the surface treatment according to the present invention is performed on the Zn-based alloy-plated steel sheet, bare corrosion resistance after processing hardly changes after 2000 hours, and only slight red rust occurs after 3000 hours.

On the other hand, as is clear from Table 2, in the case of the known chromate film composition (Comparative Examples 1, 2, 3, 4, 5), the adhesion of the formed film was poor, and chromium was considerably contained in the boiling water. Elution occurs, or the film is considerably peeled off by either treatment agent. In the case of inorganic chromate among known chromate film compositions (Comparative Examples 1 and 2), the bare corrosion resistance after processing is SST100.
A lot of red rust has occurred over time. In the case of resin chromate (Comparative Examples 3 and 4), the bare corrosion resistance after processing shows that a considerable amount of red rust occurred at SST 600 hours. Also, the adhesion of the coating film is similar,
When the surface-treating agent according to the present invention is used, even a low temperature baking type (110 ° C. baking), which is difficult to obtain paint adhesion, shows extremely excellent adhesion. On the other hand, in the case of the known chromate film (Comparative Examples 1, 2 and 3), the paint adhesion is extremely poor. Further, even when it is further coated with an organic resin (Comparative Examples 4 and 5), it is not always sufficient, and peeling of the coating film is observed.

[0049]

As described above, the surface treatment agent according to the present invention does not use chromium and is a so-called non-polluting non-chromating agent which has been conventionally used in the fields of automobiles, home appliances and building materials. And can be used as an alternative to all chromating agents such as reactive chromates. Moreover, since it is a non-polluting surface treatment agent that does not use chromium, it can be used for a wide range of applications from container-related items, tableware-related items, toys, and indoor building materials.

Claims (4)

[Claims] 1. A hydroxyl group-containing organic resin, phosphoric acid and Cu, C
o, Fe, Mn, Sn, V, Mg, Ba, Al, Ca, Sr, Nb, Y and Z
A composition for surface treatment of a chromium-free metal, which is a composition containing a phosphoric acid compound containing at least one metal of n, and which is capable of forming a film having the following characteristics (1). (1) A film formed by applying the composition on a Zn-plated steel sheet does not peel off even after being immersed in boiling water for 30 minutes. 2. The chromium-free metal surface treatment composition according to claim 1, wherein the content of the hydroxyl group-containing component in the hydroxyl group-containing organic resin is 5% by weight or more. 3. Based on 100 parts by weight of the hydroxyl group-containing organic resin,
2 to 60 parts by weight of phosphoric acid, 0.015 to 1.5 of phosphoric acid compounds
The chromium-free metal surface treating composition of claim 1 containing gram molecules. 4. SiO ₂ , Cr ₂ O ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , MgO,
The chromium-free metal surface treatment composition according to claim 1, which contains at least one of a colloid (sol) or powder of ZrO ₂ , SnO ₂ , Al ₂ O ₃ , and Sb ₂ O ₅ .