JPH03226584A - Surface treatment liquid and surface treatment method for galvanized steel sheets - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to galvanized steel sheets (electrogalvanized, electrozinc alloyed, hot-dip galvanized, alloyed galvanized, zinc-aluminum alloy plated steel sheets, etc.). nickel, cobalt, and their compounds are precipitated on the surface of the steel sheet), which allows for the subsequent tlK
It is applied for the purpose of forming an excellent surface as a base for coatings such as laminate ceramic coat, etc., and specifically, immediately after the treatment according to the present invention,
Alternatively, immediately after the treatment according to the present invention, chromate treatment and phosphate treatment are applied, and then painting 51! It is suitable for producing surface-treated steel sheets, such as coated steel sheets, laminated I-steel sheets, and surface treatment for automobile bodies, which are subjected to lamination treatment.

[Prior art]

It has been known for some time that heavy metals and their compounds can be attached to the surface of zinc-plated steel sheets through chemical treatment to improve paint adhesion or post-paint corrosion resistance. For example, as conventional examples, those described in Japanese Patent Publication No. 52-22618 and Japanese Patent Publication No. 43-12974@ are known. All of these methods precipitate heavy metals such as nickel, cobalt, and iron on galvanized steel sheets, but the invention of the above conventional example (■) involves treatment in an acidic region of pH 2, and the invention of the above conventional example (2) involves treatment in an acidic region of pH 11 or more. Heavy metals and their oxides are deposited on galvanized steel sheets in the alkaline region of . In the case of these conventional examples, excessive etching occurs due to H1 ions or OH- ions of zinc, which is an amphoteric metal, and this has the drawback of causing performance deterioration such as a decrease in corrosion resistance of the final product.

[Problem to be solved by the invention]

It is known that nickel or cobalt is substituted and precipitated on zinc-based plated steel sheets to improve the adhesion between coatings such as paint, laminates, and ceramic coats, but conventional treatment solutions are acidic or Because it is alkaline, it has the disadvantage of excessively etching the zinc material, resulting in a decline in performance such as corrosion resistance. However, in the neutral region, although there is no excessive etching, the rate of metal substitution precipitation is slow and is practically meaningless.

The present inventors have conducted extensive research into developing a rapid precipitation method for nickel and/or cobalt in a neutral region, and have found that it has good liquid stability in a neutral region and improves paint adhesion and post-painting corrosion resistance. The present invention was completed by discovering a method for quickly depositing enough candy.

When one or both of nickel and cobalt are precipitated by substitution from a treatment solution in a neutral region, the amount is sufficient to have good stability with metal ions in a neutral region and to improve paint adhesion and post-painting corrosion resistance. Amine compounds having at least one or more ammonia and primary amino groups as vine complexing agents, such as ethylenediamine, triethylenediamine, N-methylenediamine, N-n-propylethylenediamine, N,N-propylethylenediamine, 1 , 2-diaminopropane, meso-2,3-diaminobutane, rac-2,3-diaminobutane, ci
s-2,3-diaminocyclohexane, tranS-1
, 2-diaminocyclohexane, tranS-1,2-
It was discovered that one or more compounds selected from diaminoshif O hebutane, diethylenetriamine, triethylenetetramine, and various amino acids are suitable.
) has been completed. Furthermore, as a third component following metal ions and complexing agents, nitrite ions, nitrate ions,
Nickel and cobalt can be removed by adding one or more ionic species or compounds selected from carbonate ions, thiocyanate ions, thiosulfate ions, thiourea, phosphite ions, hypophosphite ions, and perchlorate ions. The invention of item (2) was completed by discovering that the displacement precipitation reaction of is significantly accelerated.

After treating a zinc-based plated steel sheet using the surface treatment liquid of the invention of item (1) or the treatment liquid of the invention of item (2), surface treatments such as chromate treatment, phosphate treatment, and black treatment are carried out. We have discovered that the corrosion resistance of galvanized steel sheets can be improved by applying the method, and that it is possible to provide a surface particularly suitable as a base for painting, laminate coating, and ceramic coating. Completed the invention.

〔composition〕

Metal ions in the treatment liquid of the present invention (hereinafter referred to as the present treatment liquid), namely one or two types of Ni2'', !:Co2+17)
a1111ffihao, 01 to 30 g/l, preferably 0.02 to Isg/l. If it is less than 0.01 g/l, the precipitation rate will be too slow to be practical, and if it exceeds 30 g/l, the precipitation rate will be saturated and it will be economically disadvantageous. Ni2+
Alternatively, CO2+ is advantageously supplied in the form of salts such as sulfates, chlorides, oxides, hydroxides, carbonates, nitrates, etc., but each can also be supplied in the form of metals. .

When nickel and/or cobalt is precipitated by displacement from a treatment solution in a neutral region, it is necessary to quickly deposit a sufficient amount to improve paint adhesion and corrosion resistance of paint equipment, while having good stability with metal ions in a neutral region. Ammonia as a complexing agent that can be precipitated, and an amine compound having at least one primary amine group, specifically ethylenediamine, triethylenetetramine, N-methylenediamine, N-n-propylethylenediamine, N-propylethylenediamine, 1.2-diaminopropane, ■ eso-2,3-diaminobutane, rac-2,3-diaminobutane, ci
s-2,3-diaminocyclohexane, tranS-1
, 2-diaminocyclohexane, trans-1,2-
One or more compounds selected from diaminocyclohebutane, diethylenetriamine, triethylenetetramine, and various amino acids are listed as essential components. These need to be added in sufficient amounts to complex nickel and cobalt.

For example, when an aqueous solution contains Ni'' and ammonia, a nickel-ammonium complex (NiA means that it is necessary to add 6 times or more of Ni2+ on a molar basis. Note that in the present invention, these The complexing agent is N1
There is no particular harm in containing more than the amount required for 2+ to be complexed, but economic efficiency and solubility determine the upper limit. Regarding the metal precipitation promotion mechanism by the complexing agent, [effect] Next, the treatment liquid in the second aspect of the present invention contains nitrite ion, nitrate ion, carbonate ion, thiocyanate ion, thiosulfate ion, thiourea, and phosphorous acid as metal precipitation promoting components. 0.001 to 509/Jl, preferably 0.05 to 509/Jl, one or more types of ions or compounds selected from ion, hypophosphite ion, and perchlorate ion.
It is desirable to contain 20 g/l. 0.0019/1
If it is less than 50 g/l, the promoting effect will be insufficient, and if it exceeds 50 g/l, the effect will be saturated and it will be economically disadvantageous.

These compounds except thiourea are specifically added in the form of alkali metal salts or ammonium salts. Note that thiourea is added in its pure form. The advantage of containing these compounds is that the fusion medium oxidation effect of the complex itself is enhanced. This action promotes the elution of zinc from the surface of the metal to be treated, thereby accelerating the precipitation of nickel or cobalt from the complex containing nickel or cobalt as the central metal element onto the metal surface.

The treatment liquid of the present invention is maintained at any temperature within the range of room temperature to boiling point, and is brought into contact with the galvanized steel sheet for a period of time required to obtain the desired amount of metal deposited. The contact method may be a dipping method, a spray method, a flow coating method, a roll coating method, a brush coating method, or the like. The appropriate range of the amount of metal deposited on a zinc-based plated steel sheet: that is, the amount of (Ni + co) deposited depends on the final purpose, but is approximately 0.1 to 100019 /
It is in the range of m.

This treatment can be washed with water, dried, and used as an adhesive base, for example.
Alternatively, it can be applied as a paint base. In this case, the appropriate amount of metal deposited is 2 to 150 .mu./1 d. 2η
/i Non-vortex did not improve the adhesion strength with the material, and 150II
If it exceeds ly/111, the effect will be saturated and it will be economically disadvantageous.

By washing with water after treatment with the surface treatment liquid of the present invention and subsequently performing chromate treatment, a surface suitable as a base for painting or lamination can be obtained. The appropriate metal material Ml at this time is 2 to 150 IRg/m, as in the case of treatment only with the liquid of the present invention.

When chromate treatment is performed not as a base for coating but as temporary rust prevention for zinc-plated steel sheets, the generation of black rust becomes a problem, but by performing treatment with the liquid of the present invention prior to chromate treatment, the generation of graphite can be prevented. can be suppressed. In this case, the appropriate amount of metal adhesion is 0.1~
5R9/TIt.

Below 0.1j19/m, there is no graphite suppression effect, and 5sy
When /d is exceeded, the white rust inhibiting effect of chromate is reduced.

Even if the surface is washed with water after treatment with the surface treatment liquid of the present invention and then subjected to phosphate treatment, a surface suitable as a base for painting or laminating can be obtained. The appropriate amount of metal deposited at this time is 2 to 150 .mu./TIt, as in the case of chromate treatment.

Baked beam O-mate type blackening treatment (patent application 1986-3105)
By carrying out the treatment with the surface treatment liquid of the present invention prior to step 42), the adhesion of the chromate-type blackened coating to the raw material and corrosion resistance can be significantly improved. The appropriate amount of M applied at this time is 2 to 1000 q/m. If it is less than 2■/TIt, adhesion and corrosion resistance cannot be improved. If it exceeds 100019/d, the effect of improving adhesion and corrosion resistance is saturated, which is economically disadvantageous.

[For production]

When nickel or cobalt is complexed with ammonia and an amine compound having at least one primary amino group, the binding force (Ita forming force) is weaker than that of other chelating agents, and these complexes Since it itself has an oxidation catalytic action and promotes the oxidation of zinc even in neutral to alkaline aqueous solutions where the solvent itself has little oxidizing ability, nickel and cobalt can be easily precipitated from these metal complexes. When using a complexing agent that does not have a partial amine, such as EDTA, a large proportion of electrons move to the central metal in the complex salt formed, which neutralizes the positive charge of the metal and reduces its activity as a catalyst. It is explained that this is to reduce the metal chelate (I[
I) "Refer to Nankodo). Nitrite ion, nitrate ion, carbonate ion, thiocyanate ion, thiosulfate ion,
The action of one or more ionic species or compounds selected from thiourea, phosphite ions, hypophosphite ions, and perchlorate ions is that when these compounds are present in the treatment liquid, they cause coordination of the metal complex. It is thought that substitutional coordination with some of the molecules lowers the stability of the complex, further increasing the oxidation catalytic activity of the complex itself.

Examples will be given below to specifically explain the effects of the present invention, and will be shown together with comparative examples.

〔Example〕

(I) Examples 1 to 10 are cases in which a galvanized steel plate was treated with the treatment solution of the present invention, and then used as a base for painting by simply washing with water and drying.

Table 1 shows the materials, treatment liquid compositions, treatment conditions, and metal adhesion conditions used in Examples 1 to 10. The treatment method used in both cases was the immersion method. The thickness of the galvanized steel sheet that is the material to be treated;
Electrogalvanizing was used with a plate width of 0.45 am, plate width: 200 mm, length: 300 M, and area weight: 20 g/m. The coating was 7 Minofurukid and the baking was done using a barcode coating of Pricon 700 (Dainippon Toyo Co., Ltd.) to a thickness of 30 μm and baking at 120°C*301 inches.

As tests after painting, primary physical properties of paint film adhesion (interlace test, Erichsen test), secondary physical properties (intersection test, Erichsen test), and a salt spray test for corrosion resistance were conducted.

The results are shown in Table 2.

1) - In the cross-cut test for large physical properties, the line spacing was set to 1 shoe, and the number of remaining stitches after the tape was peeled off was converted into the following 5-level evaluation.

2) - The Erichsen test for large physical properties was performed by extruding 5 m, and the remaining area of the coating film after peeling off the tape was evaluated in the following five stages.

3) For secondary physical property tests, the painted board was placed in boiling water for 3
After being immersed for 0 minutes, it was left indoors for 24 hours, and a cross-cut test was conducted according to 1).

4) For the Erichsen test for secondary physical properties, the coated plate was immersed in boiling water for 30 minutes, then left indoors for 24 hours, and the Erichsen test was conducted according to 2).

5) The salt spray test was conducted for 120 hours in accordance with JIS I 2371 after crosscuts were made on the coated board with a cutter. For the flat surface of the test plate, check the state of white rust,
For the cut part, peel off the tape and measure the average peeling width.
Each rating was converted into a 5-level evaluation as shown below.

Planar cut portion (II) Examples C1 to C10 are examples in which galvanized steel sheets were treated with the treatment solution of the present invention, and then washed with water and subjected to chromate treatment to serve as a base for painting.

Comparative Examples 01 to C5 are shown as comparative examples.

The galvanized steel plate that is the material to be treated has a plate thickness of 20, 35a.
al, board width: 200 m, length: 3004+111
Hot-dip galvanized steel sheet (Gl
) were treated under the conditions listed in Table 3, washed with water, and dried to obtain the metal adhesion amounts listed in Table 3. The treatment method was a spray method, and the spray pressure was 0.56+.

K9 f , /ci. These plates are coated with Cr,
259/3+.

fJ, Cr, 12g/J, gas phase silica: 60
(J/1, acrylic resin emulsion; 40g/Jl (
An O-mate treatment solution with a pH of 2.8 (containing non-volatile content) was applied using a natural coat method using a roll coat method and dried using a dryer to provide a base treatment for colored galvanized iron. The obtained skin ll1ta has Cr @ amount of 40 to 60
It was 119/'rd. The plate prepared in this way was coated with FG64 (manufactured by Dainippon Ink) as a primer for colored galvanized iron to a dry film thickness of 5 μm and maintained at a maximum plate temperature (MPT) of 210°C. Baked in a hot air drying oven.

After that, PE blue (manufactured by Dainippon Ink) was applied as a top coat to a thickness of 13 μm using a barcode, and then MP
T: It was smoked in a hot air drying oven at 210°C to obtain a top coat coated board.

Similarly, V is used as a back coat on a board that has been treated with chromate.
B-4 (manufactured by Dainippon Toyo Co., Ltd.) was coated with a bar code to a thickness of 7 μm and baked in a hot air drying oven at MPT: 210° C. to obtain a back-coated board.

Regarding the top coat coating, a bending test and a salt spray test were conducted. A salt spray test was conducted on the back-coated board.

The severity of the bending test varies depending on the number of plates that are sandwiched during bending, and the degree of OT depends on the number of plates that are sandwiched.

It is displayed as 2T etc. The temperature at the time of the test also has an effect; the lower the temperature, the more severe the test will be. For the bending test, after bending, peel off the tape and measure the peeled area as shown below.
I have added it to the graded evaluation.

In the salt spray test, the top coat was evaluated after 2000 hours, and the back coat was evaluated after 500 hours on the flat area and the cut area using the same method as in 5).

The results are shown in Table 4.

(1) Examples D1 to [)10 are also examples in which galvanized steel sheets were treated with the treatment solution of the present invention, washed with water, and subjected to chromate treatment to serve as a base for painting.

Comparative examples D1 to D5 are shown as comparative examples.

Thickness of galvanized steel sheet as the material to be treated: 0,354
11! Galvanized steel plates (GA) having a plate width of 2ooa, a length of 300 m, and a basis weight of 60 g/TIt were each treated under the conditions listed in Table 5, then washed and dried to obtain the metal adhesion amounts listed in Table 5. Ta. The treatment method was a spray method, and the spray pressure was 0.5 to 9 f/aj.
It is. Cr6+:259/3+ on these plates.

j, Cr, 12g/J), gas phase silica: 60g/N
A coated chromate treatment solution containing acrylic resin emulsion: 40 g/l (in terms of non-volatile content) and having a pH of 2.8 was applied using a natural coating method using a roll coating method and dried using a dryer to provide a base treatment for colored galvanized iron. The amount of the obtained coating was 40 to 60 WI/Td. The plate prepared in this way was coated with FG64 (manufactured by Dainippon Ink) as a primer for colored galvanized iron to a dry film thickness of 5 μm and maintained at a maximum plate temperature (MPT) of 210°C. Baked in a hot air drying oven.

After that, oil-free polyester paint is applied as a top coat to a thickness of 13 μm using a barcode, and then MP
T: Baked in a hot air drying oven at 210°C to obtain a top coat coated plate.

A back coated alkyd paint was coated with a bar code to a thickness of 7 μm on a board that had been chromate treated in the same manner, and baked in a hot air drying oven at MPT: 210°C to obtain a back coated board.

Regarding the top coat coating, a bending test and a salt spray test were conducted. For the back-coated board, a salt water *a test was conducted.

The severity of the bending test varies depending on the number of plates that are sandwiched during bending, and the degree of OT depends on the number of plates that are sandwiched.

It is displayed as 2T etc. The temperature at the time of the test also has an effect; the lower the temperature, the more severe the test will be. For the bending test, after bending, peel off the tape and measure the peeled area as shown below.
I have added it to the graded evaluation.

In the salt water spray test, the top coat was evaluated after 1000 hours, and the back coat was evaluated after 360 hours on the flat area and the cut area using the same method as in 5).

The results are shown in Table 6.

(IV) Examples E1 to EIO are also examples in which galvanized steel sheets were treated with the treatment solution of the present invention, washed with water, and subjected to chromate treatment to serve as a base for painting.

Comparative Examples E1 to E5 are shown as comparative examples.

The galvanized steel sheet that is the material to be treated has a thickness of 20.35a.
m, plate width: 200 am, length: 300 m, basis weight: 90 g/Tri galvalume steel plate (GL), that is, Zn-1! (55%) alloy-plated steel sheets were treated under the conditions listed in Table 7, washed with water, and dried to obtain the metal-coated @mouths listed in Table 5. The treatment method is a spray method, and the spray pressure is 0.5Kgf/c
It is i. Cr6+: 25g/3+ on these plates.

1, Cr, 'l2ti/1, vapor phase silica: 6
09/l, acrylic resin emulsion: 409/1
A coated chromate treatment solution containing (non-volatile content exchange sieve) with a pH of 2.8 was applied using a natural coat method using a roll coat method and dried using a drier to provide a base treatment for colored galvanized iron. The obtained film is 40-60η/T by Cr adhesion polishing.
It was. The plate prepared in this manner was coated with FG64 (manufactured by Dainippon Ink) as a paint for colored galvanized iron, or as a brimer, to a dry film thickness of 5 μm, and maintained at a maximum plate temperature (MPT) of 210°C. Baked in a hot air drying oven.

After that, PE blue (manufactured by Dainippon Ink) was applied as a top coat to a thickness of 13 μm using a barcode, and then MP
T: Baked in a hot air drying oven at 210°C to obtain a top coat coated plate.

Similarly, V is used as a back coat on a board that has been treated with chromate.
B-4 (manufactured by Dainippon Toyo Co., Ltd.) was coated with a bar code to a thickness of 7 μm and baked in a hot air drying oven at MPT: 210° C. to obtain a back-coated board.

Regarding the top coat coating, a bending test and a salt spray test were conducted. A salt spray test was conducted on the back-coated board.

The severity of the bending test varies depending on the number of plates that are sandwiched during bending, and the degree of OT depends on the number of plates that are sandwiched.

It is displayed as 2T etc. The temperature at the time of the test also has an effect; the lower the temperature, the more severe the test will be. For the bending test, after bending, peel off the tape and measure the peeled area as shown below.
I have added it to the graded evaluation.

In the salt water spray test, the top coat was evaluated after 1000 hours, and the back coat was evaluated after 360 hours on the flat area and the cut area using the same method as in 5).

flat surface Department mosquito Wow to Department The results are shown in Table 8.

[V] In Examples P1 to P10, zinc-based plated steel sheets were treated with the treatment solution of the present invention, and then washed with water and subjected to phosphate treatment. This is an example in which it is used as a base.

Comparative examples P1 to P5 are shown as comparative examples.

Thickness: 07M as a zinc-plated steel plate that is the material to be treated.
A Zn-N1 (12%) plated steel plate with a plate width of 200 m, a length of 300 ag+ and a basis weight of 20 g/m was treated under the conditions listed in Table 9, and then washed with water to obtain the metal adhesion listed in Table 9. Got the quantity. The treatment method used in both cases was the immersion method. First, each board was subjected to surface conditioning treatment (Burebaren ZN (manufactured by Nippon Paru Ising): 1 g/fJ12
o seconds, spray] Immediately after treatment without rinsing with water, apply phosphate treatment solution Parbond 3004 (Nippon Parr Ising Co., Ltd.) and Nireclone 9410 (Kansai Paint Co., Ltd.) at 40°C.
After soaking for 2 minutes, rinse with water and apply cationic electrodeposition coating, which is a typical coating system for automobile bodies; 20 μm intermediate coat, 30 μm top coat of Near Mirax Sealer (Kansai Paint), 1 top coat; Amylac White M340 μm, and perform a water resistant secondary adhesion test as shown below. It was conducted under the following conditions. The results are shown in Table 10.

Water resistance secondary adhesion test After immersing the 3-coat painted board in deionized water at 40°C for 240 hours, use an acrylic cutter to cut 100 goblets at 1 TrL/TrL intervals to reach the base metal of the painted board, and then remove the sellotape. The number of remaining marks was converted into the following 5-level evaluation and described.

Examples 1 to KIO are examples in which galvanized steel sheets were treated with the treatment solution of the present invention, and then washed with water and subjected to chromate-type blackening treatment. Comparative example 1 as a comparative example
5 is shown in ~.

The galvanized steel plate to be treated is 20.45m thick.
, board width: 200m, length: 300aa+, eye position:
209/Td electrogalvanized steel sheets (EG) are shown in Table 1.
After each treatment under the conditions described in Table 1, the samples were washed with water and dried to obtain the amount of metal deposited as shown in Table 11. The treatment method used in both cases was the immersion method. Cr+6; 80g/l on these plates
! , Cr"; 40g, '41.7 Cr resin resin material: 409/f) pH including (non-volatile content conversion):
2. Baking in 2 was performed using a group roll coating method using a chromate type blackening treatment liquid to a dry film thickness of 3 μm.
Maximum plate temperature (MFT) after coating to 20 m
A black galvanized steel sheet was obtained by baking in a hot air drying oven at a temperature of 0°C.

These blackened galvanized steel sheets were subjected to a bending test to examine the adhesion of the blackened coating to the material, and a salt spray test to examine their corrosion resistance. The bending test was conducted at 2T. In the salt spray test, the area of white rust on the flat surface after 96 hours was evaluated on a five-point scale. The results are shown in Table 12. The evaluation criteria for each test are shown below: 4° bending test, salt spray test, flat section

Claims (4)

[Claims] (1) One or two types of Ni^2^+ and Co^2^+ are used as metal ions in the surface treatment of zinc-based plated steel sheets.
．． 02 g/l or more, and an aqueous solution with a pH of 5 to 10 containing one or more compounds selected from ammonia and compounds having a primary amine group as a metal ion complexing agent. surface treatment liquid. (2) In the surface treatment of zinc-based plated steel sheets, one or two types of Ni^2^+ and Co^2^+ are used as metal ions.
．． 02 g/l or more and ammonia as a metal ion complexing agent, or one or more compounds selected from compounds having a primary amine group, and further nitrite ions, nitrate ions, and hypophosphorous acid. 1. A surface treatment solution for galvanized steel sheets, characterized in that it contains one or more substances selected from ion, thiocyanate ion, thiosulfate ion, thiourea, phosphite ion, and perchlorate ion. (3) On the surface of a clean galvanized steel sheet, 0.02 g/l or more of one or both of Ni^2^+ and Co^2^+ and ammonia or a compound having a primary amine group as a metal complexing agent. A zinc-based zinc-based material that is characterized by carrying out surface treatments such as chromate treatment, phosphate treatment, and blackening treatment after contacting with an aqueous solution of pH 5 to 10 containing one or more compounds selected from Surface treatment method for galvanized steel sheets. (4) Ni^2^+ and Co on the surface of a clean galvanized steel plate
Nitrous acid is added to an aqueous solution containing 0.02 g/l or more of one or two of ^2^+ and one or more compounds selected from ammonia or compounds having a primary amine group as a metal complexing agent. 15 to 10 aqueous solutions containing one or more substances selected from ion, nitrate ion, hypophosphite ion, thiocyanate ion, thiosulfate ion, thiourea, phosphite ion, and perchlorate ion. A method for surface treatment of a galvanized steel sheet, which comprises: contacting the galvanized steel sheet, and then subjecting it to surface treatments such as chromate treatment, phosphate treatment, and blackening treatment.