JPH02263986A - Treatment of metal surface with zinc phosphate - Google Patents

Abstract

PURPOSE:To treat a metal surface to be coated with zinc phosphate fit for coating by electrodeposition, especially cationic electrodeposition and having superior adhesion to a coating film and superior corrosion resistance by treating the metal surface with an acidic aq. zinc phosphate soln. contg. a prescribed amt. of a soluble W compd. CONSTITUTION:A metal surface, especially an iron-based surface optionally combined with a zinc-based surface is degreased with an alkaline degreasing soln. at 30-60 deg.C by spraying and/or immersion for 2 min. The degreased metal surface is washed with water and treated with an acidic aq. zinc phosphate soln. contg. 0.01-20.0g/l (expressed in terms of W) soluble W compd. at 30-70 deg.C by immersion and/or spraying for >=15sec and the treated metal surface is successively washed with tap water and deionized water. Tungstate, especially silicotungstic acid and/or silicotungstate is suitable for use as the soluble W compd.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for treating a metal surface for painting with zinc phosphate and a metal material obtained by the method, and more specifically,
Suitable for electrodeposition coating, especially cationic electrodeposition coating, on iron-based surfaces, zinc-based surfaces, aluminum-based surfaces, or metal surfaces having a combination of these surfaces, with good film adhesion, corrosion resistance, especially warm salt water resistance, The present invention relates to a treatment method for forming a zinc phosphate film soaked in scab properties.

Conventional technology Zinc phosphate coating (arsenal treatment) has been used for a long time as a metal pretreatment for painting, and spraying, dipping, or a combination of these are used as treatment methods. Although it is advantageous in terms of cost and production efficiency, it has the disadvantage that untreated parts are likely to be left on complex articles such as those with Ikekata bags, and film formation defects are likely to occur due to spray splashing.

Also, the immersion method has the disadvantage of requiring larger equipment;
Even for complex articles such as those with Ikekata bag structures, spray treatment has the advantage that a uniform film can be formed even on areas where no film is to be formed.

When forming a zinc phosphate film using the normal dipping method, the zinc ion concentration of the treatment solution is as high as 2 to 4 g/ρ, and the processing conditions are high (60 to 90°C) and for a long time (3 to 10 minutes). However, the film obtained had a high film weight (3-5 g
/ m”) and the quality of the film is poor, making it unsuitable as a base for painting, especially as a base for electrodeposition coating, due to poor adhesion, corrosion resistance, and appearance of the film.In addition, in recent years, it has been used in corrosive environments in the automobile sector, etc. Electrodeposition paints are also being replaced from anionic type to caotine type because of the demand for materials with sufficient anti-corrosion properties. Since the force is applied, the strength of the zinc phosphate film itself, which is the base for caotine-type electrodeposition coating, must be strong. Conventional processing using a treatment bath does not make the base suitable for electrodeposition coating, especially caotine electrodeposition coating. It was said that it was not possible to obtain it.

Under these circumstances, recently Japanese Patent Application Publication No. 5510778
By controlling the concentration of film formation accelerators such as zinc ions, phosphate ions, and nitrite ions in the No. 4 treatment bath, a low temperature, short-time immersion method achieves a low film amount, uniform and dense adhesion, and excellent corrosion resistance. A method for forming a film that could be used as a base for electrodeposition coating was proposed, and the dipping method suddenly came into the spotlight. That is, in the invention of the same patent application, zinc ions were contained in a range of 0.5 to 1.5 g/n, and phosphate ions were contained in a range of 5 to 1.5 g/n.
The metal surface was immersed at 40 to 70°C for 15 to 120 seconds in an acidic zinc phosphate treatment solution containing 30 g/ρ and nitrite ions as 0.01 to 0.2 g/ρ. , then the same treatment liquid as above for the purpose of sludge removal.

1 by spraying for 2-60 seconds at the treatment temperature.
．． It forms a base suitable for uniform and dense electrodeposition coating with a low coating amount of 5 to 3 g/'m2.

After that, steel materials plated with zinc or alloyed zinc on only one side began to be used as body materials mainly in the automobile industry for the purpose of further improving the corrosion resistance after painting, and although immersion treatment in the treatment bath described above poses no problem on iron-based surfaces, For zinc-based surfaces, there are problems such as insufficient salt spray resistance after cationic electrocoating, and secondary adhesion after the first and top coats is significantly inferior to iron-based surfaces. In order to deal with this issue, for example, Japanese Patent Application Laid-open No. 57-15
No. 2472, in which 0 manganese ions are added to a bath with controlled concentrations of zinc ions, phosphate ions, and a film formation accelerator.
．． 6-3g/ρ and/or nickel ion 0.1-
0.05g of fluorine ion with manganese ion for the purpose of containing 4g/l or lowering the processing temperature
A technique for adding more than /ρ (Japanese Patent Publication No. 61-36588) has been developed.

In this way, it is possible to provide a chemical conversion film suitable for electrodeposition coating on iron-based surfaces, or on metal surfaces that have both an iron-based surface and a zinc-based surface, by zinc phosphate treatment using the dipping method. It is now possible to immerse a wide range of products, including not only building materials and small articles, but also automobile bodies and other automobile parts, in zinc phosphate chemical conversion treatment, the main purpose of which is to improve the corrosion resistance of articles with iron, zinc, and their alloy surfaces. The law has now established a firm foundation.

However, in recent years, the quality requirements for corrosion resistance of automobile bodies have become more and more sophisticated.
There are strong demands for prevention of scab-like rust (scab corrosion) that forms on steel surfaces, and higher resistance to warm salt water, and current zinc phosphate treatment methods are becoming unable to meet these demands.

On the other hand, spray treatment is still the mainstream for steel furniture, etc., but galvanized steel sheets are being introduced in this field as well to improve rust prevention, and even these are not always satisfactory in terms of adhesion and corrosion resistance. It has not been.

Furthermore, it is desired to improve scab resistance and hot salt water resistance through pretreatment.

Aluminum materials are also widely used in various fields such as automobiles and building materials, and there is a demand for zinc phosphate treatment on the surfaces of iron or zinc materials containing aluminum materials.

However, when iron materials containing aluminum are treated with the conventionally proposed acidic zinc phosphate treatment bath for iron or zinc materials, aluminum ions are generated in the treatment bath, and when the amount exceeds a certain amount, the iron It is known that chemical formation defects may occur. That is, it has been found that poor chemical formation of iron materials occurs when 30AI is 5 ppm or more in a treatment solution that does not contain fluorine ions, 1100 ppm or more in a treatment solution containing HBF4, and 300 ppm or more even in a treatment bath containing H2SIF6. ing. Therefore, in order to reduce the A1 content of 30% in the processing solution, acidic potassium fluoride was added to the processing solution.
+ Add 1 Hisoda to AI to 2NaAIF6
Alternatively, a method of precipitating Na3AlF6 as Na3AlF6 has been proposed in JP-A-57-70281, but when such aluminum precipitates are deposited on the coated film, defects in cationic electrodeposition coating occur and the film lacks uniformity. In this method, it is necessary to remove the suspended sediment from the treatment solution, as it causes poor secondary adhesion of the paint film (not only does it complicate the process, but it also reduces the effectiveness of the process). It has also been proposed to control the treatment ratio of aluminum to iron to 3/7 or less, and to maintain the A1 ion concentration in the fluorine thread subsulfate treatment solution to 70 ppm or less. (Unexamined Japanese Patent Publication No. 61-10408
No. 9), it is difficult to maintain the AI ion concentration at 70 ppm or less simply by lowering the processing ratio of the aluminum material by 3+.

Problems to be Solved by the Invention Therefore, a method for treating an iron-based surface, a zinc-based surface, an aluminum-based surface, or a metal surface having a combination of these surfaces with zinc phosphate, which has corrosion resistance suitable for painting, especially electrodeposition coating, is provided. (In addition to being able to provide an arsenal coating, the scab resistance of iron surfaces and the hot salt water resistance of iron and zinc surfaces are particularly improved, and it is also excellent for iron or zinc surfaces including aluminum materials. There is a need for a treatment method that can provide a corrosion-resistant coating and further improve the secondary adhesion when applying an intermediate coat or top coat to an electrodeposited plate, and it is of great importance to address this issue. It is for the purpose of invention.

Means for Solving the Problems The present inventors have achieved the above object by treating the metal surface with a soluble tungsten compound of 0.01 to 20.0 g of tungsten.
Acidic zinc phosphate treatment containing /β This can be achieved by a method for treating metal surfaces with zinc phosphate, which is characterized by treatment with an aqueous solution (rIL).Soluble tungsten compounds include tungstates, such as sodium tungstate and tungstic acid. Although ammonium etc. are also used, silicotungstic acid and/or silicotungstate compounds exhibit the above-mentioned effects significantly, and furthermore, in specific concentration ranges of zinc, nickel, manganese metal ions and fluorine ions, silicotungstate It was discovered that the effects of acids and/or tungstate silicate compounds can be particularly pronounced, and the method of the present invention was completed.

The present invention is most effective when targeting a metal surface having an iron-based surface or a combination of an iron-based surface and a zinc-based surface, but is not limited to this. It goes without saying that other metal surfaces can also be treated for the same purpose. That is, the present invention targets metal surfaces of any of the above embodiments.

An example of a tree that is practically advantageous for the treatment method of the present invention is as follows. First, coat the metal surface with alkaline absorbent cotton at a temperature of 3.
Degrease by spraying and/or dipping at 0 to 60°C for 2 minutes, then washing with tap water, and then spraying and/or dipping with a surface conditioner at room temperature for 10 to 30 seconds if dipping. Then, it may be immersed and/or sprayed in the above-mentioned acidic zinc phosphate treatment aqueous solution of the present invention at a temperature of 30 to 70° C. for 15 seconds or more, and then washed with tap water and deionized water.

When the present invention is used in immersion treatment, the zinc ion which is the main component of the treatment liquid of the present invention is 0.1 to 2. Og/g, preferably 0.3 to 1.5 g/ffl.

0°1 g/! If it is less than 2, a uniform zinc phosphate film will not be formed on the metal surface, and a partially blue-colored film with many streaks will be formed. In addition, if the concentration exceeds 2.0 g/l, a uniform zinc phosphate film will be formed, but the film on the surface will easily dissolve in alkali, and in particular, the film will be easily dissolved by the alkaline atmosphere exposed during cationic electrodeposition. .

As a result, the resistance to hot salt water generally decreases, and the desired performance cannot be obtained, such as poor scab resistance in the case of iron-based surfaces, making it unsuitable as a base for electrodeposition coatings, especially cationic electrodeposition coatings. Appropriate. The amount of phosphate ion is 5 to 40 g/II, preferably 10 to 30 g/II. If it is less than 5 g/l, a non-uniform film is likely to be formed, and if it exceeds 40 g/l, no effect greater than that of the present invention can be expected, and the amount of chemicals used increases, which is economically disadvantageous. The soluble tungsten compound is 0.01 to 20.0 g/Jl as tungsten, preferably 0.05 to 10.0 g/Jl! More preferably 0 than Q
．． It is 1 to 3.0 g/II. If it is less than 0.01 g/p, the modification of the zinc phosphate film will be insufficient, and the scabbing resistance and hot salt water resistance will not improve. Furthermore, in the treatment of aluminum materials, the effect of suppressing elution of aluminum becomes insufficient.

On the other hand, if it exceeds 20 g/l, the amount of tungsten will be more than it contributes to the film reaction, and no effect beyond the present invention can be expected, and a large amount of thick sludge will be produced, which is not preferable.

Nitrite ion 0.01 to 0.5 to promote film formation
g/ρ, preferably 0.01-0.4 g/II, m-nitrobenzenesulfonic acid ion 0.05-5 g/l
, preferably 0.1 to 4 g/uJl and 3M hydrogen oxide (
8202100% conversion) 0°5~Log/, &, preferably 1~8g/(at least one kind selected from) may be used.

If these accelerators do not reach a specified amount, sufficient film formation cannot be formed on the iron-based surface, resulting in yellow rust, and if the amount exceeds the specified amount, a blue-collar uneven film tends to be formed on the iron-based surface.

As sources of these main components, for example, zinc ions may be zinc oxide, zinc carbonate, zinc nitrate, etc., phosphate ions may be phosphoric acid, zinc phosphate, manganese phosphate, etc., and soluble tungsten compounds may be sodium tungstate, sodium tungstate, etc. Tungstate salts such as ammonium tungstate, borotungstic acid, phosphotungstic acid, phosphotungstic acid = i
In addition to h, silicotungstic acid and silicotungstate f arsenic compounds are preferably used, but silicotungstic acid may be a commercially available product, and soluble silicotungstate monoarsenate is an alkali metal salt of silicotungstic acid. , ammonium salts, alkaline earth metal salts, and the like are selected. It is particularly desirable to use silicotungstic acid or geytungstate in a treatment solution for the surface of aluminum materials or iron or zinc materials containing aluminum materials.

The film formation accelerator is sodium nitrite, ammonium nitrite, m-
2) Sodium lobenzenesulfonate, aqueous arsenic peroxide, etc. may be used.

In addition, in the case of spray treatment, it improves the chemical conversion of the zinc phosphate film for the paint base onto the metal surface, and in addition, it reduces the consumption of nitrite to less than half compared to conventional treatment solutions, and the by-product sludge and further reduce the amount generated by 1/3 to 1/3
4, and the phosphate ion concentration in the treatment solution during chemical conversion treatment is at least 5 g/II.
, nitrite ion 0.02-0.5 g/p, zinc ion concentration at least 0.3 g/ffl, phosphate ion:
The molar weight ratio of nitrate ions is 1:0.7 to 1.3, and the molar ratio of phosphate ions:zinc ions is 1:0116.
For example, Japanese Patent Publication No. 55-5
As proposed in No. 590 and attracting attention, in the present invention, the soluble tungsten compound is at least 0.01% of tungsten even in such a treatment agent and also in a normal zinc phosphate treatment solution for spraying. ~20g/
By containing it in the concentration range of 1, it is possible to significantly improve scab resistance, hot salt water resistance, adhesion, especially adhesion to zinc-based surfaces, as well as the desired effects.

Furthermore, when the treatment liquid of the present invention contains manganese ions, nickel ions, and fluorine ions in a specific concentration range in addition to the above-mentioned main components, the effects of the soluble tungsten compound can be exhibited in a complementary manner. In particular, when targeting iron or zinc materials containing aluminum materials, as mentioned above, silicotungstic acid or silicotungstate salt is selected as the soluble tungsten compound, and
It is desirable to contain fluorine ions at a specific concentration.

Fluorine ion is 0.05 to 4 g/l, preferably 0.1
~2 g/,2. If it is less than 0.05 g/ρ, it will adversely affect the f arsenability of the iron material.

Further, it is undesirable because the allowable upper limit concentration of aluminum remaining in the in-situ treatment bath for metal surfaces containing aluminum material becomes low. Furthermore, if the fluorine ion concentration exceeds 4 g/ρ, the effect of improving the resistance to hot salt water tends to be reduced. Fluorine ions can be supplied with hydrofluoric acid, borofluoro-mono-arsenic acid, gay-fluoro-hydro-arsenic acid, and their metal salts; The upper limit concentration is 1100pp, and when supplied with fluorine arsenic acid or its salt, 300pp.
Although not essential, it is most preferable that fluorine ions be supplied by arsenic acid or a metal salt thereof in the aluminum material treatment bath.

Manganese ion is 0.1~3g/! 2, preferably 0.6 to 3 g/'A. 0゜1
g/' (If it is less than 1, the adhesion of the zinc-based surface and the effect of improving hot and salt water resistance will be insufficient, and if it exceeds 3 g/ρ, the effect of improving corrosion resistance will be insufficient.Nickel ion is 0.
．． In the range of 1 to 4 g/l, preferably 0.1 to 2 g/f
The range is fl. If it is less than 0.1 g/ff1, the effect of improving corrosion resistance due to the combined use with a soluble tungsten compound will be insufficient, and if it exceeds 4 g/ff1, the effect of improving corrosion resistance will tend to be reduced. As sources of these components, for example, manganese ions may be manganese carbonate, manganese nitrate, manganese chloride, manganese phosphate, etc., and nickel ions may be nickel carbonate, nickel nitrate, nickel chloride, nickel phosphate, nickel hydroxide, etc. , fluorine ions may be hydrofluoric acid, hydrofluoroboric acid, hydrofluorosilicic acid, their metal salts, etc., nitrate ions may be sodium nitrate, ammonium nitrate, zinc nitrate, manganese nitrate, nickel nitrate, etc., and chlorate ions may be Sodium chlorate, ammonium chlorate, etc. may be used.

The treatment temperature using the treatment liquid of the present invention may be 30 to 70°C, preferably 35 to 60'C. If the temperature is too low, the film formation properties will be poor and a long treatment time will be required. If the temperature is too high, the balance of the treatment solution is likely to be lost due to decomposition of the coating accelerator and precipitation of the treatment solution, making it difficult to obtain a good coating.The treatment time may be 15 seconds or more, preferably 30 to 120 seconds. If the time is too short, a film having the desired crystals will not be sufficiently formed. In addition, when treating an article with a complicated shape such as an automobile body, it is practically preferable to combine immersion treatment and spray treatment. , then spray treatment for 2 seconds or more, preferably 5 to 45 seconds. In addition, in order to wash off the sludge deposited during the immersion treatment, it is preferable that the spray treatment be carried out for as long as possible. Therefore, the treatment according to the present invention includes treatment modes such as dipping treatment, spray treatment, and combinations thereof.

The present invention also relates to a concentrated processing agent that provides a processing liquid having the above-mentioned composition. In this concentrated processing agent, the weight ratio of the zinc ion source and the phosphate ion source is in ionic form, and the soluble tungsten metal source is the weight as tungsten, and the weight ratio is zinc ion diphosphate ion: Soluble tungsten compound (as W) = 1:2.
It is composed of two parts: liquid (A), which is adjusted by mixing to give a ratio of 5 to 4oo:o, and liquid (B), which is an accelerator liquid, and by diluting these and mixing them appropriately, A processing solution having the above composition can be easily prepared. Note that ion sources other than the main component, such as manganese ions, nickel ions, fluorine ions, nitrate ions, and chlorate ions, can be added to the solution (A). However, the chlorate ion source may be added to solution (B) instead of solution (A). In particular, when adding a manganese ion source to solution (A), the chlorate ion source may be added to solution (B). It is preferable to do so. The soluble tungsten compound source may be added to the solution (B) so that the ratio of zinc ion to tungsten compound m-1 is 0.005 to 200 by weight as tungsten.

It is recognized that when a tungstate salt such as sodium tungstate or ammonium tungstate is used, the film obtained by the treatment method of the present invention definitely contains tungsten.

According to the present invention having the above-described structure, it is possible to treat not only iron-based surfaces but also zinc surfaces, aluminum surfaces, or metal surfaces having a combination thereof at the same time, even after initial and continuous treatment, as a coating base, especially an electrodeposited surface. It is suitable as a coating base, especially as a base for cationic electrodeposition coating, and can form a film with excellent corrosion resistance, particularly scab resistance, and good hot water resistance and adhesion.

The present invention will be explained below with reference to Examples.

(Examples 1 to 7, 10 to 12, and Comparative Examples 1 to 7) (
1) Metals to be treated: (a) Alloyed molten zinc: Alloyed molten galvanized steel sheet (1
7) Electrolytic zinc: electrogalvanized steel sheet (8) Alloyed electrolytic zinc di-alloyed electrogalvanized steel sheet (d) Cold rolled steel sheet (2) Acidic zinc phosphate treatment aqueous solution: 17 types having the composition shown in Table 1 (3) Treatment process The above four types of metal surfaces ((1) (a) to (d)) are treated at the same time according to the following steps: washing - dry soot → painting (4) Each treatment condition (a) Degreasing: Use an alkaline degreasing agent manufactured by Nippon Paint Co., Ltd.
Surf cleaner-5D250J 2 weight? ≦concentration) and immersion treatment at 40"C for 2 minutes.

(b) Washing with water: Wash with tap water for 15 seconds at room temperature.

(c) Surface conditioning: Using a surface conditioning agent (Surf Fine 5N-5J, manufactured by Japan India Co., Ltd., 0.1% by weight), immersion treatment is carried out at room temperature for 15 seconds.

(d) 1st Formation: Using the above acidic zinc phosphate treatment aqueous solution, immersion treatment is carried out for 120 seconds at the temperature shown in Table 1 (52°C or 40°C).

(e) Washing with water: Wash with tap water for 15 seconds at room temperature.

(f) Pure water washing: Using ion-exchanged water, immersion treatment is performed at room temperature for 15 seconds.

(g) Drying: Dry with hot air at 100°C for 10 minutes. The appearance and weight of the chemical conversion coating of the chemical conversion treated board thus obtained were measured.

(h) Painting: Apply cationic electrodeposition paint (manufactured by Nippon Paint Co., Ltd., "Power Top Bee 80 Gray") to a dry film thickness of 20 μm at 180°C (voltage: 180cm, current application time: 3 minutes). Bake for 30 minutes until crispy. A portion of the electrodeposited plate obtained is subjected to a warm salt water immersion test. Spray coat the remaining electrodeposited plate with an intermediate coating (Nippon Paint Co., Ltd.'s "Olga T○4811 Gray", melamine alkyd resin system) to a dry soot film thickness of 30μ, and heat it at 140℃ for 20 minutes. Bake for minutes. Next, a top coat (Olga T○ 630 Doper White, manufactured by Nippon Paint Co., Ltd., melamine alkyd resin system) was spray-painted to a dry film thickness of 40 μm, baked at 140°C for 20 minutes, and the entire surface was sealed. Obtain a painted board with 3 coats and 3 bakes. This is subjected to an adhesion test and a scap test.

(Example 8.9 and Comparative Example 8.9) (1) Metals to be treated: (a) Alloyed molten zinc: Alloyed hot-dip galvanized steel sheet (b) Electrolytic zinc: electrolytic galvanized steel sheet (c) Alloyed Electrolytic zinc; Alloyed electrogalvanized steel sheet (d) Cold rolled steel sheet (2) Acidic zinc phosphate treatment aqueous solution: 4 types having the composition shown in Table 1 were used (3) Treatment process The above 4 types ((1) ) The metal surfaces of (a) to (d)) were treated simultaneously according to the following steps (4) Each treatment strip (a) Degreasing: Using an alkaline degreaser (manufactured by Nippon Paint Co., Ltd.)
Surf Cleaner 3102, 2% concentration by weight) at 50° C. for 2 minutes.

(1)) Washing with water: Use tap water to wash for 15 seconds at room temperature.

(C) 1. Using the above acidic zinc phosphate treated aqueous solution, spraying pressure 0.7kg/'cnf, 120°C at 55°C.
Spray for seconds.

(d) Washing with water: Wash with tap water for 15 seconds at room temperature.

(e) Pure water washing: Using ion-exchanged water, immersion treatment is performed at room temperature for 15 seconds.

(f) Drying (g) Coating: Dry with hot air at 100°C for 10 minutes. The appearance and weight of the chemical conversion coating of the chemical conversion treated board thus obtained were measured.

Apply cocationic electrodeposition paint (Nippon Paint Co., Ltd. "Power Top Bee 80 Gray") to a dry film thickness of 20 μm (voltage: 180 V, energizing time: 3 minutes), 180°.
Bake at C for 30 minutes. A portion of the electrodeposited plate obtained is subjected to a warm salt water immersion test. Apply intermediate coating paint (manufactured by Nippon Paint Co., Ltd.) to the remaining electrodeposition coated board.
Baked "Olga TO4811 Gray" (melamine alkyd resin system) to a dry film thickness of 30
Spray paint so that it becomes μ and bake at 140°C for 20 minutes.

Next, top coat paint (Olga TO630 manufactured by Nippon Paint Co., Ltd.)
Doper White, melamine alkyd resin) was spray-painted to a baked dry film thickness of 40μ, and heated at 140°C.
Bake for 20 minutes to obtain a painted board with 3 coats and 3 bakes. This is subjected to an adhesion test and a scap test.

Test results: Various tests were conducted on the various test plates obtained in each of the above Examples and Comparative Examples, and the results are shown in Table 2. In addition, each test method is shown below.

<A) Warm salt water immersion test A cut was made with a sharp cutter on the electrodeposition coated plate, and 5%, 5%
After 480 hours of immersion in saline at 5°C, an adhesive tape was applied to the cut portion and then peeled off, and the maximum peeling of the coating was measured.

(B) Adhesion test: After immersing the painted board in deionized water at 40°C for 20 days,
In addition to this, there are 100 pieces of positive rows at intervals of 1 and 2 mm.
using a sharp cutter, attach adhesive tape to each side, peel them off, and count the number of goblin coatings remaining on the painted board.

(C) Scab test A cut was made on the painted board with a sharp cutter, and then the painted board was subjected to a 5% salt spray test (JIS-Z-2371, 24
time) → Humidity test (humidity 40℃, relative humidity 85%, 12
0 hours) - left indoors (24 hours) 1 cycle is 10
I took 1 inch for the cycle @food test (hereinafter referred to as the scab test). The amount of corrosion on the painted surface after the test was investigated.

In addition, as the tungsten compounds of the above examples, Examples 1 to
Examples 8 and 10 used ammonium tungstate, Example 9 used sodium tungstate, and Examples 11 and 12 used silicotungstic acid, respectively.

Example 13.14 Comparative Example 10.11.12 (1) Object to be treated A) Alloy 1 Hot dip galvanized steel sheet Mouth) Cold rolled steel sheet C) Aluminum alloy sheet (Al/14g alloy system) (2)
Four types of acidic zinc phosphate treated aqueous solutions having the compositions shown in Table 3 were used.

<3) Treatment process The above three types of metal surfaces ((1) (a) to (c)) are treated at the same time at a ratio of 80% and 10.10% of the area to be treated, respectively.
Process according to the following steps.

Degreasing → Water washing → Surface conditioning → Chemical formation → Water washing → Pure water (Tirafu) Washing - Dry shell coating (4) Each treatment condition (a) Degreasing: Alkaline degreaser (manufactured by Nippon Pain Co., Ltd.)
Surf Cleaner 5D25 0”, 2 weight? 6 concentration) and immersion treatment was performed at 40°C for 2 minutes.

[Bath management] Alkalinity (10 samples were taken, and the mQ number of 0 and 1 NHCl required for neutralization using bromophenol blue as an indicator)
maintain. Surf Cleaner 5D250 was used as a replenishment agent.

(c) Surface conditioning Using a surface conditioning agent (manufactured by Nippon Paint Co., Ltd. "Surf Fine 5N-5J 0.1% concentration by weight),
Dip for 15 seconds at room temperature.

[Bath management] Maintain alkalinity (same as above).

The replenishing agent was Surf Fine 5N-5 (d) Chemical formation: The above acidic zinc phosphate treated aqueous solution was used and immersion treatment was carried out at 40°C for 2 minutes.

[Bath management] Concentration and free acidity of each ion composition in the above acidic zinc phosphate treated aqueous solution (number of mU of 0, I N NaOH required for neutralization when 10 mM was collected and bromophenol blue was used as an indicator)
maintain. Supply chemical sharpeners include Zn, PO4, Mn, Ni, W, F, and NO.
In order to maintain the concentration of each ion in step 3, a concentrated treatment agent A for replenishment containing zinc white, phosphoric acid, manganese nitrate 7 carbonate nigel, silicotungstic acid, silifluoric acid (or borofluoric acid) and nitric acid, and N02 In order to maintain the ion concentration, replenishment concentrated processing agent B containing thorium nitrite was used. In addition, in Comparative Figure 1 12, in order to maintain the A1 concentration of the zinc phosphate treated aqueous solution at 50 ppm or less, an aluminum lam precipitation additive C containing acidic monohypotassium fluoride and acidic sodium fluoride at a molar weight ratio of 2:1, respectively. It was used.

(e>(f> Example 3 Same test results as Example 1) In Example 13, the equilibrium concentration of aluminum ions in the zinc phosphate treated aqueous solution was 160 ppm, but all three types of treated objects were suitable as a good base for painting. showed that.

In Comparative Example 10, the aluminum ion concentration was 300 pp
If the concentration exceeds 400 ppm, the film formation property of the cold-rolled steel sheet is poor (yellowing occurs), and the coating quality is poor.

In Example 14, the equilibrium degree of aluminum ion is 80.
ppm, but all three types of objects to be treated showed good suitability as a base for painting.

Comparative Example 11 has an aluminum ion concentration of 1100 pp
The amount exceeded 200 ppm, and the film formation property of the cold-rolled steel sheet was poor (yellowing occurred).

In Comparative Example 12, the aluminum ion concentration was 50 pp
However, the tendency of aluminum precipitates to settle on the object to be treated increases, and the suitability of the coating base becomes worse. (Lack of uniformity of cationic electrodeposition coating film) Source of F Example 13, Comparative Example 10) 12siF6
Example 14 and Comparative Examples 11 and 12 are 1 (source of BF4W) silicotungstic acid (1) The present invention includes the following embodiments.

(1) The method according to claim 1, wherein the treatment method is immersion treatment.

(2) The soluble tungsten compound is sodium tungstate, ammonium tungstate, borotungstic acid, phosphotungstic acid, phosphotungstate, geytungstic acid, alkali metal geytungstate, ammonium silicate, alkaline earth silicate tungstate. The method according to claim 1, wherein the salt is at least one selected from the group consisting of metal salts.

(3) The film formation accelerator contains nitrite ions of 0.01 to 0.
5g/η, m-nitrobenzenesulfonic acid ion 0.0
5-5g/(and hydrogen peroxide 0.5-Log/ffl
The method according to claim 1, wherein the method is at least one selected from the following.

(4) The acidic zinc phosphate treated aqueous solution contains 0 manganese ions.
．． 1-3 g/! ;l, fluorine ion 0.05-4
The method according to claim 1, comprising at least one of g/', R, and 0.1 to 4 g/β of nickel ions.

(5) Acidic zinc phosphate treatment aqueous solution has nitrate ions of 0.1~
15g/ff and/or chlorate ion 0.05-2
．． 4. The method of claim 1 or claim 3, comprising less than 0 g/, &.

(6) The method according to claim 1, wherein the treatment temperature is 30 to 70°C.

(7) The method according to claim 1, comprising a dipping treatment or a combination of first dipping treatment for 15 seconds or more and then spraying treatment.

(8) The method according to claim 1, wherein the metal surface has an iron-based surface, a zinc-based surface, or both an iron-based surface and a zinc-based surface.

(9) The metal surface has an aluminum-based surface or an aluminum-based surface, an iron-based surface, and a zinc-based surface at the same time, and the acidic zinc phosphate treatment aqueous solution contains zinc ions of 0.1
~2. Og/ρ, phosphate ion 5-40 g/, Q
2. The method according to claim 1, wherein the main components are 0.05 to 4 g/ρ of fluorine ion, 0.01 to 20 g/ρ of tungsten silicotungstic acid and/or tungstate silico, and a film formation accelerator.

(10) Zinc ion source, phosphate ion source and tungsten ion source (as W) at 1+2.5 to 400:0.
2 for adjusting by dilution the acidic zinc phosphate treated aqueous solution of claim 1, comprising component (A) contained in a weight ratio of 0.005 to 200 and component (B) containing a film formation accelerator.
Liquid type concentrated processing agent.

(11) The two-component concentrated processing agent according to item 8 above, wherein W is added to (B).

(12) A metal material having a tungsten-containing zinc phosphate film obtained by the method according to claim 1.

(13) Contains zinc ion 0.1-2.0g/ff, phosphate ion 5-40g/ρ, soluble tungsten compound 0.01-20.0g/l as tungsten, and film formation accelerator as main components. A metal material having a tungsten-containing zinc phosphate film obtained by treating with an acidic zinc phosphate treatment aqueous solution.

patent application agent Patent Attorney ± 1A Takeo Fuji

Claims (2)

[Claims] (1) A method for treating a metal surface with zinc phosphate, which comprises treating the metal surface with an acidic zinc phosphate treatment aqueous solution containing a soluble tungsten compound of 0.01 to 20.0 g/l as tungsten. (2) The metal surface is treated with 0.1 to 2.0 g/l of zinc ions, 5 to 40.0 g/l of phosphate ions, 0.01 to 20.0 g/l of tungsten as a soluble tungsten compound, and a film formation accelerator. The method according to claim 1, characterized in that the treatment is carried out with an acidic zinc phosphate treatment aqueous solution containing as a main component.