JP2003147544A - Surface treatment film of zinc plated film, surface treatment solution for zinc plated film, and surface treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treatment technique for a zinc-plated product which is hard to be rusted even when stored over a long period, and has high surface luster and an, e.g. yellow, noncolored appearance, and has no problems in an odor, skinning properties, and sludge, and has excellent corrosion resistance and operability. SOLUTION: The surface treatment solution for a zinclated film has a pH of 2.5 to 7.0, and contains a trivalent chromium compound and a fluorine compound.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a film excellent in surface gloss, corrosion resistance, and workability by treating a product plated with zinc or a zinc alloy with a surface treatment liquid that does not contain hexavalent chromium harmful to the human body and environment. Of technology.

[0002]

Zinc plating is made of metal,
In particular, it is widely used as a corrosion protection method for steel materials. Incidentally, in order to further improve the corrosion resistance and other characteristics of zinc plating, zinc alloy plating may be performed. In the present specification, zinc plating and zinc alloy plating are collectively referred to as “zinc-based plating”.

Zinc-based plated products (molded products) include secondary processed products such as roll forming, bending, welding, cutting, etc., guard rails, U-shaped steel, H
In addition to steel and L-shaped steel, it is also widely used for small items such as bolts and nuts.

Since the sacrificial anticorrosion by the zinc-based plating is effective and economical, it is used in a wide range of fields such as building materials, automobiles and home appliances.

That is, in the case of sacrificial corrosion by zinc, when a battery is formed under the condition that two metals, zinc and steel, are in contact with each other, zinc, which is a base metal, serves as an anode, iron becomes a cathode, and iron alone is used. This is to prevent the dissolution of the anode in the formation of the local battery and to prevent the corrosion of the steel material. Therefore, since the rust preventive action ends when the zinc in contact with the steel material disappears, it is necessary to suppress the corrosion of the zinc layer in order to maintain its action effect for a long time. As a result, chromate treatment is applied after plating.

Among the molded products, particularly the guard rails and U-shaped steel materials are required to have high plating surface gloss.
In order to prevent rusting during storage until construction, a hexavalent chromium compound is generally treated with chromic anhydride. This is a hexavalent chromic acid compound such as 0.1 to 0.4 g / L of sodium dichromate and ammonium dichromate at 60 ° C.
This is a method in which a plated molding is treated with a treatment liquid heated to 80 ° C., pulled up and dried as it is. Further, as a treatment liquid other than the chromic anhydride treatment, a technique has been developed which enables high gloss and primary rust prevention by treating with an aqueous solution of a water-soluble resin and drying.

However, recently, there is a tendency that the period from on-site delivery of plated moldings to construction is prolonged, and such chromic anhydride treatment or water-soluble resin treatment causes a problem of rusting. ing.

[0008] As a countermeasure for this, there has been taken a measure to improve the corrosion resistance by increasing the anhydrous chromium concentration which is a hexavalent chromium compound to 0.5 to 2.0 g / L. When treated, there is a drawback that the appearance after treatment becomes yellowish and the glossiness tends to be low.

Further, when the primary rust prevention treatment is not carried out, normally,
Since it is not heated, the temperature drops to room temperature, but the problem of spoilage of the water-soluble resin drug may occur. Furthermore, in order to improve the corrosion resistance of the water-soluble resin chemicals, the carboxylic acid in the resin is neutralized or made alkaline with volatile ammonia, etc., but when the temperature of the treatment liquid is high, it volatilizes gradually, which may cause odor. There may be problems such as deterioration of working environment and deterioration of productivity such as skinning of the surface treatment liquid and adhesion of the surface treatment liquid to a molded product due to generation of aggregates and precipitates.

When a chromic anhydride treatment liquid which is a hexavalent chromium compound is used, the metal in the galvanization, especially zinc, dissolves into the treatment liquid by etching, and finally becomes sludge such as zinc chromate, which causes heat. Stick to the exchanger,
There are also problems such as adherence to plated molded products.

Further, as is well known, since hexavalent chromium compounds are harmful to the human body, wastewater treatment using hexavalent chromium is costly. Further, also in the chromate-treated galvanized steel material, it is feared that hexavalent chromium will be eluted from the chromate film after disposal and pollute the surrounding environment.

Therefore, a hexavalent chromium-free chemical conversion treatment liquid containing no hexavalent chromium compound has been demanded.

From this point of view, an aqueous solution containing a trivalent chromium compound and at least one metal compound selected from titanium compounds, cobalt compounds, tungsten compounds and silicon compounds is used, and hexavalent chromium, fluoride and A chemical conversion treatment liquid for zinc or zinc alloy plating, which does not contain a complex fluoride anion and an oxygen acid anion of phosphorus, has been proposed (JP 2000-234177).

However, although the proposed technique does not contain hexavalent chromium, it is not preferable in that it requires washing with water after the treatment, is inferior in workability, and requires wastewater treatment.

Therefore, the problem to be solved by the present invention is that the zinc-plated product has characteristics that it does not easily rust even if it is stored for a long period of time, and that it has a high surface gloss and a non-colored appearance such as yellow. Further, it is to provide a surface treatment technology for a zinc-based plating film which is excellent in corrosion resistance and workability without problems of odor, skinning property and sludge.

[0016]

[Means for Solving the Problems] As a result of intensive research conducted by the present inventors, trivalent Cr compounds and F
When a film that is poorly soluble in water containing water is formed on the surface of the zinc-based plating film, it does not rust easily, and has a high surface gloss and a non-colored appearance such as yellow.
It has been found that there is no problem of sludge and it is excellent in corrosion resistance, glossiness and workability.

That is, the above problem is a surface treatment solution for a zinc-based plating film, and the surface treatment solution has a pH of 2.
It is 5 to 7.0, and is solved by a zinc-based plating film surface treatment liquid characterized by containing a trivalent chromium compound and a fluorine compound.

In the present invention, the surface treatment liquid has a pH of 2.
The reason for setting 5 or more is as follows.

When the pH is less than 2.5, that is, when the acidity becomes strong, the etching amount of zinc becomes large, the generation of sludge becomes large, and the work such as washing with water becomes necessary. Is contained in a larger amount, the poor solubility is lowered and the corrosion resistance is deteriorated. In addition, the pH of the surface treatment liquid is 3.0 or more, further 3.5
The above is preferable.

The reason why the pH is 7.0 or less is as follows.

As the pH of the surface treatment liquid increases, the stability of the treatment liquid decreases. This is because the trivalent chromium compound precipitates as chromium hydroxide.
In addition, zinc is a metal that dissolves in both acidic and alkaline conditions, so if the pH increases, the problem of zinc dissolution will arise. From such a viewpoint, the pH is set to 7 or less. still,
It is preferably 5.0 or less, more preferably 4.5 or less.

The pH may be adjusted with an acid or an alkaline compound as needed. For example, phosphoric acid, sulfuric acid,
Inorganic acids such as nitric acid and hydrochloric acid, organic acids such as acetic acid, oxalic acid, succinic acid and maleic acid, and alkali metal compounds such as sodium hydroxide and potassium hydroxide can be used. Of course, when it is not necessary to use these pH adjusters, there is no need to use them.

In the present invention, the trivalent chromium compound is 3
It is a compound capable of supplying valent chromium ions, that is, a trivalent chromium salt. Salts include, for example, phosphates, nitrates, sulfates,
Examples thereof include inorganic acids such as hydrochlorides, organic acid salts such as acetates, oxalates and succinates. Such compounds include:
For example, chromium (III) fluoride, chromium chloride (II
I), chromium (III) nitrate, chromium (III) sulfate,
Examples thereof include chromium (III) acetate. Among them, chromium (III) fluoride is the most preferable. Such a trivalent chromium compound has a Cr content of 0.05 to 3.0.
The concentration is preferably g / L, more preferably 0.1 to 0.5 g / L.

In the present invention, the fluorine compound is a compound capable of supplying fluorine ions. Examples of such a compound include chromium (III) fluoride, magnesium (II) fluoride, iron (II) fluoride, cobalt (II) fluoride, nickel (II) fluoride and the like.
Among them, chromium (III) fluoride is the most preferable. Such a fluorine compound has an F of 0.05 to
It preferably has a concentration of 3.0 g / L, more preferably 0.1 to 0.5 g / L.

It is preferable that the surface treatment liquid of the present invention further contains one or more metal compounds selected from the group consisting of manganese, cobalt and nickel. The manganese compound, the cobalt compound, and the nickel compound are compounds that supply the cation of each metal, and examples thereof include a manganese salt, a cobalt salt, and a nickel salt. Examples of the salt include inorganic acids such as phosphates, nitrates, sulfates and hydrochlorides, and organic acid salts such as acetates, oxalates and succinates. These compounds have the advantage of improving the corrosion resistance while maintaining the surface gloss. It is considered that this is because it is incorporated into the film composed of the composition containing trivalent Cr and F and exhibits a kind of sacrificial anticorrosive action. The manganese compound has a Mn of 0.01 to 3.
The concentration of 0 g / L, more preferably 0.1 to 0.5 g / L is preferable, and the nickel compound is 0.01 as Ni.
To 3.0 g / L, more preferably 0.1 to 0.5 g / L, and the cobalt compound is 0.01 to 3.0 g / L as Co and further 0.1 to 0. 0.5 g / L
Those having a concentration of This is because if the concentration of the compound is too low, it is difficult to form a film having a sufficient film thickness to improve the corrosion resistance, and if the concentration is too high, the gloss of the plating surface decreases and the appearance tends to be colored. is there.

The treatment liquid of the present invention is usually used in the form of an aqueous solution. When the compound used in the present invention is not soluble (poorly soluble or insoluble) in water, for example, when chromium fluoride is used, it is dissolved using an acid such as an organic acid or an inorganic acid. For example, inorganic acids such as phosphoric acid, sulfuric acid, nitric acid and hydrochloric acid, organic acids such as acetic acid, oxalic acid, succinic acid and maleic acid are used for dissolution. It is also conceivable to heat it in order to make it easy to dissolve in water.

A water-soluble or water-dispersible resin may be added to the treatment liquid of the present invention.

Further, the above-mentioned subject is characterized in that it comprises a contacting step of bringing the zinc-based plating film into contact with the above zinc-based plating film surface treatment liquid, and a drying step of drying after the contacting step. This is solved by the surface treatment method of the zinc-based plating film.

The treatment conditions may be the same as the conventional treatment conditions for chromic anhydride. For example, the processing temperature is 40
The range of 100 ° C to 100 ° C is suitable. More preferably 80
C. or lower, more preferably 60 to 70.degree. Appropriate processing time is in the range of 1 to 600 seconds. It is more preferably 10 seconds to 60 seconds, further preferably 20 seconds to 30 seconds. The treatment is generally immersion. However, other treatment methods such as spraying and pouring may be used. That is,
It only needs to be naturally dried after the treatment. In the case of immersion, a suitable stirring means, for example, rocking of the plated molding, air stirring,
It is desirable to apply pump stirring, stirring with a stirrer, and stirring with ultrasonic vibration. There is no problem even if the heat treatment is performed after the natural drying.

The coating film obtained as described above is particularly 3
It is a poorly water-soluble (including insoluble) film containing Cr and F having a valency of 0.5 to 30 mg / m ² in Cr concentration.
In particular, it is a film of trivalent Cr and F having a thickness of 3 to 15 mg / m ² , which is hardly soluble (including insoluble) in water, and has the above-mentioned characteristics.

That is, the above problem is a protective film provided on the surface of a zinc-based plating film, the protective film being a film that is sparingly soluble or insoluble in water and contains trivalent Cr and F. This is solved by a surface treatment film of a zinc-based plating film characterized by containing.

A protective film provided on the surface of the zinc based plating film, wherein the protective film is formed by the above zinc based plating film surface treatment liquid. Membrane surface treatment is solved by the membrane. .

In particular, the protective film is provided on the surface of the zinc-based plating film, and the protective film is a film that is sparingly soluble or insoluble in water formed by the zinc-based plating film surface treatment liquid. And a zinc-based plating film surface treatment film.

That is, the surface-treated film thus formed has a corrosion resistance higher than that of a conventional hexavalent chromium-based or water-soluble resin chemical film against zinc-based plating, as shown in the following examples.

In the beach area where the use environment is particularly severe,
Corrosion resistance may be required extremely strongly. In such a case, further coating can be performed to further improve the performance.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION The zinc-based plating film surface treatment liquid according to the present invention is a zinc-based plating film surface treatment liquid, and the surface treatment liquid has a pH of 2.5 to 7.0 (particularly 3.
0 or more, further 3.5 or more. Also, 5.0 or less, further 4.5 or less. ) And containing a trivalent chromium compound and a fluorine compound. The pH can be adjusted with an acid or an alkaline compound as necessary. For example, phosphoric acid, sulfuric acid, nitric acid, inorganic acids such as hydrochloric acid, acetic acid, oxalic acid, succinic acid,
An organic acid such as maleic acid or an alkali metal compound such as sodium hydroxide or potassium hydroxide can be used. Of course, when it is not necessary to use these pH adjusters, there is no need to use them. The trivalent chromium compound is a compound capable of supplying trivalent chromium ions, that is, a trivalent chromium salt. Examples of the salt include inorganic acids such as phosphates, nitrates, sulfates and hydrochlorides, and organic acid salts such as acetates, oxalates and succinates. Examples of such compounds include chromium (III) fluoride, chromium (III) chloride,
Examples include chromium (III) nitrate, chromium (III) sulfate, and chromium (III) acetate. Among them, chromium (III) fluoride is the most preferable. Like this 3
The valent chromium compound is 0.05 to 3.0 g /
L, more preferably 0.1 to 0.5 g / L. The fluorine compound is a compound that can supply fluorine ions. Examples of such a compound include chromium (III) fluoride, magnesium (II) fluoride, iron (II) fluoride, cobalt (II) fluoride, nickel (II) fluoride and the like. Among them, chromium fluoride (I
II) is the most preferred. Such a fluorine compound has an F of 0.05 to 3.0 g / L, and further has a F.O.
Those having a concentration of 1 to 0.5 g / L are preferable. Further, it further contains one or more metal compounds selected from the group consisting of manganese, cobalt and nickel. The manganese compound, the cobalt compound, and the nickel compound are compounds that supply the cation of each metal, and examples thereof include a manganese salt, a cobalt salt, and a nickel salt. Examples of the salt include inorganic acids such as phosphates, nitrates, sulfates and hydrochlorides, and organic acid salts such as acetates, oxalates and succinates. The manganese compound has a Mn of 0.01 to 3.
The concentration of 0 g / L, more preferably 0.1 to 0.5 g / L is preferable, and the nickel compound is 0.01 as Ni.
To 3.0 g / L, more preferably 0.1 to 0.5 g / L, and the cobalt compound is 0.01 to 3.0 g / L as Co and further 0.1 to 0. 0.5 g / L
Those having a concentration of The treatment liquid of the present invention is usually used in the form of an aqueous solution. When the compound used in the present invention is not soluble (poorly soluble or insoluble) in water, for example, when chromium fluoride is used, it is dissolved using an acid such as an organic acid or an inorganic acid. For example, inorganic acids such as phosphoric acid, sulfuric acid, nitric acid and hydrochloric acid, organic acids such as acetic acid, oxalic acid, succinic acid and maleic acid are used for dissolution. It is also conceivable to heat it in order to make it easy to dissolve in water. Further, a water-soluble or water-dispersible resin may be blended.

The surface treatment method for a zinc-based plating film according to the present invention comprises a contacting step for bringing the zinc-based plating film into contact with the above zinc-based plating film surface treatment solution, and a drying step for drying after the contacting step. Have. The treatment conditions may be the same as the conventional treatment conditions for chromic anhydride. For example, the treatment temperature is suitably in the range of 40 ° C to 100 ° C. It is more preferably 80 ° C or lower, and further preferably 60 ° C to 70 ° C. Appropriate processing time is in the range of 1 to 600 seconds.
It is more preferably 10 seconds to 60 seconds, further preferably 20 seconds to 30 seconds. The treatment is generally immersion. However, other treatment methods such as spraying and pouring may be used.
That is, it suffices if it can be naturally dried after the treatment. In the case of dipping, it is desirable to apply an appropriate stirring means such as rocking of the plated molding, air stirring, pump stirring, stirring by a stirrer, and stirring by ultrasonic vibration. There is no problem even if the heat treatment is performed after the natural drying.

The surface-treated film of the zinc-based plated film according to the present invention is a protective film provided on the surface of the zinc-based plated film, and the protective film is a film that is sparingly soluble or insoluble in water. It has a valency of Cr and F. In particular, it is formed by the above zinc-based plating film surface treatment liquid. Further, it is a film that is hardly soluble or insoluble in water and formed by the above zinc-based plating film surface treatment liquid. Further, the film has a Cr concentration of 0.5 to 30 mg / m ² , particularly 3 to 15
It is a poorly water-soluble (including insoluble) film containing trivalent Cr and F having a thickness of mg / m ² .

Examples of the present invention will be described below together with comparative examples.

[0040]

[Example 1] Galvanized guard rail molding (300
(g / m ² ), and after cooling, it was immersed in a surface treatment liquid consisting of a 1 g / L aqueous solution of chromium fluoride at pH 3.0 (adjusted with ammonia and sulfuric acid) at 70 ° C. for 30 seconds. During the treatment, the surface treatment liquid was circulated by a pump.

Then, it was taken out of the surface treatment solution and naturally dried.

The amount of the surface-treated coating thus formed was 5 to 10 mg / m ² as the total amount of chromium.

[0043]

Example 2 Instead of the surface treatment liquid used in Example 1,
The procedure was carried out in the same manner as in Example 1 except that a surface treatment solution containing an aqueous solution containing 1 g / L of chromium fluoride and 0.5 g / L of cobalt nitrate at pH 3.0 (adjusted with ammonia and sulfuric acid) was used. .

[0044]

Example 3 Instead of the surface treatment liquid used in Example 1,
At pH 3.5 (adjusted with ammonia and sulfuric acid), 1 g / L of chromium fluoride, 0.5 g / L of nickel sulfate, and 0.
The same procedure as in Example 1 was performed except that a surface treatment solution containing an aqueous solution containing 5 g / L of cobalt nitrate was used.

[0045]

Example 4 Instead of the surface treatment liquid used in Example 1,
Example 1 except that a surface treatment liquid consisting of an aqueous solution containing 1 g / L ammonium fluoride, 1 g / L chromium nitrate, and 0.5 g / L cobalt sulfate at pH 3.5 (adjusted with nitric acid) was used. It was carried out according to.

[0046]

Example 5 Instead of the surface treatment solution used in Example 1,
1 g / L ammonium fluoride, 0.5 g / L chromium phosphate, and 0.5 g / L at pH 3.0 (adjusted with sulfuric acid)
Example 1 was repeated except that the surface treatment liquid consisting of the aqueous solution containing manganese sulfate was used.

[0047]

Example 6 Instead of the surface treatment liquid used in Example 1,
Example 1 except that a surface treatment liquid consisting of an aqueous solution containing 2 g / L potassium fluoride, 1 g / L chromium sulfate, and 0.5 g / L manganese hydrochloride at pH 3.0 (adjusted with sulfuric acid) was used. It was carried out according to.

[0048]

Comparative Example 1 Guardrail moldings were galvanized in the same manner as in Example 1, cooled, and then dipped in a surface treatment solution containing an aqueous solution containing 0.2 g / L of sodium dichromate at 70 ° C. for 30 seconds. did. During the treatment, the surface treatment liquid was circulated by a pump.

Then, it was taken out of the surface treatment solution and naturally dried. The amount of the surface-treated coating thus formed was 3 to 5 mg / m ² as the total amount of chromium.

[0050]

[Comparative Example 2] A guardrail molded product was galvanized in the same manner as in Example 1, cooled, and then immersed in a surface treatment solution containing an aqueous solution containing 1.5 g / L of ammonium dichromate at 70 ° C for 30 seconds. did. During the treatment, the surface treatment liquid was circulated by a pump.

After that, it was taken out from the surface treatment solution and naturally dried. The amount of the surface-treated coating thus formed was 15 to 30 mg / m ² as the total amount of chromium.

[0052]

[Comparative Example 3] A guardrail molded article was galvanized in the same manner as in Example 1, cooled, and then manufactured by Toyo Yakuka Kogyo Co., Ltd.
The EBO # AW-20 was immersed in a surface treatment solution prepared by mixing 1: 1 with water at 70 ° C. for 30 seconds. During the treatment, the surface treatment liquid was circulated by a pump.

Then, it was taken out of the surface treatment solution and naturally dried as it was.

The amount of the surface-treated coating thus formed was 0.5 to 1.0 g / m ² .

[0055]

Comparative Example 4 Instead of the surface treatment liquid used in Example 1,
In accordance with Example 1 except that a surface treatment liquid consisting of an aqueous solution containing 2 g / L of chromium fluoride at pH 2.0, 0.5 g / L of chromium sulfate, and 0.5 g / L of manganese hydrochloride was used. went.

[0056]

Comparative Example 5 Instead of the surface treatment liquid used in Example 1,
0.3 g / L chromium fluoride at pH 7.5, 0.2 g / L
Example 1 except that a surface treatment liquid consisting of an aqueous solution containing L of chromium nitrate and 0.5 g / L of cobalt sulfate was used.
It was carried out according to.

[0057]

Comparative Example 6 Instead of the surface treatment liquid used in Example 1,
0.2g / L chromium sulfate at pH 3.0, and 0.5g
The same procedure as in Example 1 was performed except that a surface treatment liquid containing an aqueous solution containing / L cobalt sulfate was used.

[0058]

Comparative Example 7 Instead of the surface treatment liquid used in Example 1,
The procedure of Example 1 was repeated except that a surface treatment solution containing an aqueous solution containing 0.02 g / L ammonium fluoride and 0.5 g / L manganese sulfate at pH 4.0 was used.

[0059]

Comparative Example 8 Instead of the surface treatment liquid used in Example 1,
0.02 g / L manganese sulphate at pH 4.5 and 0.
The same procedure as in Example 1 was performed except that a surface treatment solution containing an aqueous solution containing 005 g / L of cobalt chloride was used.

[0060]

Comparative Example 9 Instead of the surface treatment liquid used in Example 1,
45 g / L chromium nitrate nonahydrate, 62.5% sulfuric acid 2
The procedure was carried out in the same manner as in Example 1 except that a surface treatment liquid consisting of an aqueous solution (pH 1.0) containing g / L and 2 g / L sodium fluoride was used.

[0061]

[Characteristics] The products obtained in the above Examples and Comparative Examples were subjected to a salt spray test (SST) according to JIS-Z-2371 to evaluate the corrosion resistance. In this evaluation, the white rust of the molded product after 24 hours and 48 hours of SST was expressed in area%.

The surface gloss was also examined. The surface gloss was evaluated relative to the untreated plated molding. The ∘ mark has a gloss similar to that of the untreated sample, the Δ mark shows a little less gloss than that of the untreated sample, and the X mark shows that the gloss is apparently less than that of the untreated sample.

The stability of the treatment liquid was also examined. The evaluation is a molded product after plating (plate size: 7 × 15c
m) One sheet was immersed at room temperature for 8 hours, then pulled out, and another molded article was immersed again, and the appearance of precipitation was visually evaluated. O indicates that no precipitation was generated, Δ indicates that precipitation was slightly observed, and X indicates that precipitation was observed.

The odor was also examined. The evaluation is
The surface treatment liquid was heated to 70 ° C., and the presence or absence of odor in the treatment liquid was confirmed.

The results are shown in Table 1.

[0066]                             Table-1           Corrosion resistance (24hr) Corrosion resistance (48hr) Surface gloss Stability Odor Example 1 10% 20% ○ ○ None Example 2 7% 15% ○ ○ None Example 3 6% 14% ○ ○ None Example 4 5% 5% ○ ○ None Example 5 10% 15% ○ ○ None Example 6 5% 10% ○ ○ None Comparative Example 1 50% 100% ○ ○ None Comparative Example 2 20% 50% × ○ None Comparative Example 3 20% 70% With △ △ Comparative Example 4 10% 15% ○ △ None Comparative Example 5 8% 12% ○ △ None Comparative Example 6 25% 40% ○ ○ None Comparative Example 7 30% 35% ○ ○ None Comparative Example 8 40% 50% ○ ○ None Comparative Example 9 30% 50% × ○ None Comparative Example 10 100% 100% ---     * Comparative Example 10 is untreated with the surface treatment liquid.

[Effects of the Invention] The zinc-plated product does not easily rust even if it is stored for a long period of time, has a high surface gloss and has an uncolored appearance such as yellow, and further has odor, skin-tightness, and sludge. We provide surface treatment technology for zinc-plated products with excellent corrosion resistance and workability

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Minoru Kuramoto             1-15-1 Nihonbashi, Chuo-ku, Tokyo Japan Par             Within Colorizing Co., Ltd. F term (reference) 4K026 AA02 AA07 AA11 AA22 BA01                       BA06 BB01 BB08 BB10 CA13                       CA14 CA19 CA23 CA26 CA28                       CA32 CA33 CA34 CA36 CA38                       DA03 DA05 DA06 EB11

Claims (10)

[Claims] 1. A surface treatment solution for a zinc-based plating film, wherein the surface treatment solution has a pH of 2.5 to 7.0 and contains a trivalent chromium compound and a fluorine compound. Zinc-based plating film surface treatment solution. 2. The surface treatment liquid for zinc-based plating film according to claim 1, wherein the surface treatment liquid has a pH of 3.0 to 5.0. 3. The trivalent chromium compound is one or more compounds selected from the group consisting of chromium fluoride, chromium chloride, chromium nitrate, chromium sulfate and chromium acetate. Zinc-based plating film surface treatment solution. 4. The fluorine compound is one or more compounds selected from the group consisting of chromium fluoride, magnesium fluoride, iron fluoride, cobalt fluoride and nickel fluoride. Item 1. A zinc-based plating film surface treatment liquid according to item 1. 5. The zinc-based plating film surface treatment liquid according to claim 1, wherein the trivalent chromium compound and the fluorine compound are chromium fluorides. 6. The surface treatment liquid further contains one or more metal compounds selected from the group consisting of manganese, cobalt and nickel. Zinc-based plating film surface treatment solution. 7. A zinc-based plating film according to any one of claims 1 to 6.
A surface treatment method for a zinc-based plated film, comprising: a contact step of contacting with any surface treatment solution for zinc-based plated film; and a drying step of drying after the contact step. 8. A protective film provided on the surface of a zinc-based plating film, wherein the protective film is a film that is sparingly soluble or insoluble in water and contains trivalent Cr and F. Surface treatment film for zinc-based plating film. 9. A protective film provided on the surface of a zinc-based plated film, wherein the protective film is formed by the zinc-based plated film surface treatment liquid according to any one of claims 1 to 6. A surface treatment film for a zinc-based plating film, which is characterized in that 10. A protective film provided on the surface of a zinc-based plating film, wherein the protective film is resistant to water formed by the zinc-based plating film surface treatment liquid according to any one of claims 1 to 6. A surface-treated film of a zinc-based plating film, which is a soluble or insoluble film.