JP2000319790A - Surface treated steel sheet for fuel vessel and coating material composition therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a surface treated steel sheet using a Zn or Zn alloy plated steel sheet as a base stock, being excellent in corrosion resistance against degraded gasoline containing organic acids, provided with advanced weldability, having excellent formability and suitable for a fuel tank for automobiles. SOLUTION: A thermosetting resin layer containing one or more kinds of metallic pigments A selected from Ni, Al and an Ni-Al alloy and one or more kinds of pigments B selected from iron phosphide and ferrosilicon in a modified epoxide resin is applied by 3-10 g/m2 coating weight on the chemically converted Zn or Zn alloy plated steel sheet. The total quantity of the pigment in the resin layer is preferably controlled to 10-70 wt.%, the ratio of pigment A/ pigment B is preferably controlled to 90/10 to 30/70 and the average particle diameter of each pigment is preferably controlled to 0.5-15 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet made of a galvanized steel sheet, which is suitable for a fuel container (fuel tank) of an automobile using gasoline as a fuel. The present invention relates to a surface-treated steel sheet which exhibits high corrosion resistance even to deteriorated gasoline containing an organic acid and also has excellent weldability, and a paint used for producing the surface-treated steel sheet.

[0002]

2. Description of the Related Art Materials for fuel tanks for automobiles and motorcycles (hereinafter collectively referred to as automobiles) using general gasoline as fuel include corrosion resistance on inner and outer surfaces, particularly corrosion resistance on inner surface fuel (gasoline), press formability. , And weldability are required.

[0003] As a material for a fuel tank satisfying such performance, Pb-10 to 25% is conventionally called a turn sheet.
Sn alloy plated steel sheets have been widely used. However, materials that do not contain Pb, which is harmful to the human body, have come to be required mainly due to environmental problems. Further, a higher level of corrosion resistance to fuel is required, for example, performance in a deteriorated gasoline environment containing an organic acid is required.

In response to this request, Al-plated steel sheets (for example,
JP-A-9-156027), Sn-Zn-plated steel sheets (for example, JP-A-8-269733) have been developed as alternatives. Of these, Al-plated steel sheets have problems in joining properties such as welding and soldering, and materials with improved usability by processing manufacturers and the like are desired. In this regard, Sn-about 8
% Zn alloy plated steel sheet is said to have a good balance of performance, but since the plating itself is almost exclusively used for fuel tanks, the market size is small, and there is a problem in terms of stable supply and price. Therefore, it would be economically advantageous if relatively inexpensive zinc-based plating (that is, Zn plating or Zn alloy plating), which is widely used in general, could be applied to fuel tanks.

Japanese Patent Application Laid-Open No. 10-137681 discloses a technique for applying a Zn-based plated steel sheet to an automobile fuel tank. According to this publication, an amine-modified epoxy resin layer containing Ni and Al metal powders is coated on the inner side on a zinc-plated steel sheet subjected to a chromate treatment, and a silica-containing resin layer containing wax on the outer side. Coated surface treated steel sheets have been proposed.

[0006]

SUMMARY OF THE INVENTION In the surface-treated steel sheet described in Japanese Patent Application Laid-Open No. H10-137681, Ni and
The corrosion resistance inside the tank is exhibited by the Al metal powder, but the resistance of the coating is large and the weldability is inferior, so it has been found that the usability for the user (fuel tank manufacturer) is poor. In this publication, unleaded gasoline / 500 pp
m 1/1 mixed solution of formic acid aqueous solution, ie, formic acid concentration of 25
Although the internal corrosion resistance is tested at 0 ppm, the concentration of formic acid in degraded gasoline can reach about 1000 ppm, and a higher level of internal corrosion resistance has been required.

Using a Zn-based plated steel sheet, it is economical and has high corrosion resistance to gasoline containing a deteriorated organic acid (hereinafter referred to as deteriorated gasoline corrosion resistance),
Until now, it has not been easy to obtain a low-cost fuel tank material with good performance balance that can ensure stable weldability. An object of the present invention is to develop such a fuel tank material.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to use Zn-based plated steel sheets as a material to achieve a high balance between deteriorated gasoline corrosion resistance and weldability.
Forming a resin layer containing a pigment selected from iron phosphide and ferrosilicon in addition to a metal pigment selected from Ni, Al, and Ni-Al alloy on the upper layer of the system-plated steel sheet with a specific adhesion amount As a result, it has been found that a steel plate for a fuel container having good deterioration gasoline corrosion resistance and weldability of the tank inner surface can be obtained.

According to the present invention, at least one surface of a galvanized steel sheet is coated with Ni, Al and Ni-Al alloy.
One or two or more metal pigments A and one or two pigments B selected from iron phosphide and ferrosilicon in a weight ratio of pigment A / pigment B of 90/10 to 30/70. ,
And wherein the amount of the pigment total have at a coverage of 3 to 10 g / m ² a thermosetting resin layer containing in an amount in the range of 15 to 70 wt% of the resin layer, a fuel container for surface treatment It is a steel plate.

[0010] In another aspect, the present invention relates to a resin and a solvent, one or more metal pigments A selected from Ni, Al and Ni-Al alloy, and iron phosphide and ferrosilicon. A paint composition containing one or two pigments B selected from the group consisting of:
Production of a surface-treated steel sheet for a fuel container, characterized in that it is in the range of 10 to 30/70 and the total amount of pigments is in the range of 15 to 70% by weight based on the solid content of the coating composition. It is a coating composition for use.

Preferably, the average particle size of each pigment is 0.5 to 15
μm, and the resin component in the resin layer is a modified epoxy resin.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As a base material of a base material plated steel sheet, a general cold-rolled steel sheet which is usually used may be used. However, since steel plates for fuel tanks are generally subjected to severe press forming, it is preferable to use, for example, a component system having extremely low carbon and added with Ti, Nb, and B.

[0013] Material of the surface treated steel sheet of the plating present invention, consider the economics are relatively cheap mass production, Zn-plated steel sheet or a Zn alloy plated steel sheet (these, zinc or Zn-based in the present invention (Collectively referred to as plated steel sheets). Examples of Zn alloy plating include Zn-Al, Zn-Al-Si, Zn-Ni, Zn-Fe, Zn-Cr,
Examples include, but are not limited to, Zn-Co, Zn-Mg, and Zn-Sn. In addition, as for Zn alloy, Zn is slightly less than 50% like Zn-55% Al alloy plating (for example, 40 to 50%).
%) Alloys are also included. The plating method may be any of a hot-dip plating method, an electroplating method, and a vapor deposition plating method. Plating is basically double-sided plating, but it is not impossible to perform single-sided plating only on the inner side.

Examples of the coated steel sheet that can be used in the present invention include electric Zn-coated steel sheet, hot-dip Zn-coated steel sheet, and electric Zn alloy.
(E.g., Zn-Ni) Plated steel sheet, hot-dip Zn alloy (e.g., Zn-Al)
There are alloy plated steel sheets, alloyed hot-dip Zn plated steel sheets, and the like. The coating weight is 10 g / m ² per side from the viewpoint of corrosion resistance.
It is preferably at least 15 g / m ² .

Pigment-containing resin layer A pigment-containing resin layer is formed on at least one surface of the above-mentioned Zn-based plated steel sheet according to the present invention. Since this resin layer is particularly excellent in deteriorated gasoline corrosion resistance, it may be formed only on one side corresponding to the inner surface side of the tank, but since it has sufficient corrosion resistance also on the outer surface side, Both may form a pigment-containing resin layer according to the present invention.

The required performance of the resin for the inner surface is degraded gasoline corrosion resistance of the inner surface, adhesion to the underlying treatment, and weldability. In order to satisfy all of these performances at a high level, in the present invention, Ni, Al, Ni
One or more metal pigments selected from -Al alloys
(Hereinafter referred to as Pigment A) and a resin layer containing one or two kinds of pigments (hereinafter referred to as Pigment B) selected from iron phosphide and ferrosilicon, and having an adhesion amount after drying of 3 to 10 g / m ² . Therefore, the coating composition used for forming the resin layer contains the pigment A and the pigment B in addition to the resin and the solvent.

Of the metal pigment A in the resin layer, ie, Ni powder, Al powder and Ni-Al alloy powder, Ni powder is mainly added for the purpose of developing the deteriorated gasoline corrosion resistance and ensuring a certain degree of weldability. On the other hand, Al powder is added for the purpose of improving the corrosion resistance of deteriorated gasoline. As the gasoline deteriorates, organic acids such as formic acid and acetic acid are generated, which becomes severe as a corrosive environment. In such an environment, Al powder is particularly effective. Ni powder and Al
Both of the powders may be used in combination. Even when the Ni-Al alloy powder is used, the deteriorated gasoline corrosion resistance of the inner surface and a certain degree of weldability can be obtained as in the case where the Ni powder and the Al powder are used in combination.

However, as described in connection with the prior art, simply blending the metal pigment A in the resin layer results in a resin layer having an excessively high film resistance and providing a high degree of weldability that provides satisfactory usability to users of steel sheets. I can't secure it. Therefore, the present inventors, in order to ensure a high degree of weldability, to earnestly study the pigment type to be contained in the resin layer, to ensure a higher degree of spot weldability without impairing the deteriorated gasoline corrosion resistance. It has been found that it is effective to add pigment B composed of iron phosphide and / or ferrosilicon to the resin layer in addition to pigment A.

The total amount of pigment A and pigment B is
Therefore, it is preferred that the amount occupies 15 to 70% by weight (based on the weight of the solid content of the coating composition), particularly 20 to 50% by weight. If it is less than 15% by weight, sufficient weldability cannot be ensured. On the other hand, if the content exceeds 70% by weight, it becomes extremely difficult to apply uniformly to the surface of the steel sheet, or the amount of the pigment is too large, and the desorption of the pigment occurs during press molding, resulting in poor moldability. .

The ratio of the pigment A / pigment B is determined by the ratio of the pigment A / P in order to highly balance the corrosion resistance of deteriorated gasoline and the weldability.
The weight ratio of pigment B is 90/10 to 30/70, especially 90/10 to 40/60.
It is preferable to be within the range. If the weight ratio is more than 90/10, the amount of the pigment B is too small and the weldability is slightly insufficient. If the weight ratio is less than 30/70, the pigment A is too small and the deteriorated gasoline corrosion resistance is slightly insufficient.

The resin layer of the present invention is required to fulfill the function of blocking the corrosion promoting component contained in the deteriorated gasoline from the steel plate and the function of the pigment binder described above. Therefore, it is necessary to form a dense film in which the resin itself does not easily dissolve, swell or permeate the gasoline component. Suitable resin species for this purpose are thermosetting resins whose coatings are densified by crosslinking. Specifically, epoxy-based, acrylic-based, urethane-based, polyester-based, phenol-based resins and the like are mentioned as suitable resin types.

Resins particularly suitable for use in the resin layer in the present invention are modified epoxy resins such as amino-modified and urethane-modified, and among them, urethane-modified epoxy resin is preferable. The urethane-modified epoxy resin is a resin obtained by reacting an epoxy resin with a dibasic acid to form an epoxy ester resin, and then reacting a terminal carboxyl group of the resin with a polyisocyanate compound to form an urethane. The obtained resin has the same skeleton as the epoxy resin, and a part of the terminal is urethanized. Urethane-modified epoxy resin as the base resin of the resin layer has a number average molecular weight of about 5000
Those in the range of ~ 50,000 are preferred. On the lower molecular weight side, it swells easily with gasoline, and on the high molecular weight side, it is difficult to produce, and in addition, the permeation resistance of the corrosion promoting component contained in deteriorated gasoline is inferior.

When the base resin is an epoxy resin or a modified epoxy resin, it is necessary to use a curing agent. Examples of suitable curing agents include phenolic resins, melamine resins, benzoguanamine resins, and the like. Considering the corrosion resistance of deteriorated gasoline, a phenol resin capable of forming a resin layer having a higher molecular weight is preferable as the curing agent.

(Modified) The weight ratio of epoxy resin / curing agent is
A range of 50/50 to 98/2 is preferred. If the amount of the curing agent is too large, the film becomes hard and brittle, and the workability is reduced. If the amount of the curing agent is too small, curing will not proceed sufficiently, and the deterioration gasoline resistance will decrease. This weight ratio is more preferably 70 / 30-90.
/ 10, more preferably 75/25 to 85/15. In addition,
When a curing agent is used, the amount of the curing agent is included in the amount of the resin. Various epoxy resin liquids containing a curing agent are commercially available, and the above-mentioned pigments A and B can be mixed therewith and used for forming the resin layer of the present invention.

The adhesion amount of the pigment A, the thermosetting resin layer containing B is, 3~10 g / m ^2, preferably in the range of 4~7g / m ^2. When the amount is less than 3 g / m ² , the corrosion resistance in a gasoline environment is inferior. When the amount exceeds 10 g / m ² , the effect is saturated, the cost is increased, and even if the pigment B of the present invention is used, sufficient welding is performed. Will not be obtained.

The shape of the powder of the pigment A and the pigment B contained in the resin layer in the present invention is not particularly limited. That is, the shape may be any of a granular shape, a scale shape, a needle shape, an irregular shape, and the like. It is preferable that each pigment has an average particle diameter (average value of the maximum particle diameter in the case of non-granular shape) in the range of 0.5 to 15 μm. When the adhesion amount of the resin layer is 5 g / m ² or more, more preferably, the average particle size is 5 to 5 times of the resin thickness (which can be calculated from the specific gravity of the resin layer or measured by SEM or the like). 150
%, And more preferably in the range of 0.5 to 15 μm described above. Even when the amount of the resin layer adhered is 3 to 5 g / m ² , it is preferable that the average particle size of the pigment does not exceed 150% of the resin thickness. If the average particle size of the pigment is too small, the conductivity of the resin layer is reduced. If the average particle size is too large, the physical distance between the pigments in the overlapped portion at the time of welding is long, so that both are inferior in weldability.

The size of the Al powder is not particularly defined in terms of the effect of improving the corrosion resistance by the chemical action. However, as described in JP-A-10-137682, a scaly shape of about 10 μm is considered more preferable because a physical shielding effect is expected.

In the resin layer, in addition to the conductive pigment A and the conductive pigment B, optional components such as a coloring pigment, a rust-preventive pigment (eg, an alkaline earth metal chromate), and other conductive pigments , A silica, a silane coupling agent and the like can be contained within a range that does not significantly deteriorate the performance of the resin layer such as the deteriorated gasoline corrosion resistance, weldability, and workability.

The resin layer is formed by adding a predetermined amount of conductive pigments A and B and, if desired, other components to a resin solution in which the resin is dissolved or dispersed in a solvent, and uniformly dispersing or dissolving the coating composition. It can be formed by preparing and applying this coating composition to a plated steel sheet, and then heating and baking the coating to cure the resin. The coating method and the baking temperature are not particularly limited, and can be appropriately selected by those skilled in the art. When the resin is a urethane-modified epoxy resin, the baking temperature is preferably in the range of 170 to 250 ° C. The paint may be either a water-based paint or a solvent-based paint.

In addition, prior to forming the above resin layer on the Zn-based plated steel sheet, it is difficult to perform a well-known base treatment such as chromate treatment or phosphate treatment for the purpose of improving the adhesion of the resin layer and the corrosion resistance of the plated steel sheet. However, the effects of the present invention are not reduced at all. The chromate treatment may be any of a coating type, a reaction type, and an electrolytic type. If the amount of the base treatment is too large, the weldability may be impaired. Therefore, it is preferable not to make the amount too large.

Since steel plates for fuel tanks are generally subjected to severe press forming, it is desirable to enhance lubricity especially on the outer surface of the tank in order to perform the pressing without any trouble. Therefore, when the resin layer of the present invention is formed on both surfaces of the steel sheet, a solid lubricant film can be formed particularly on the upper layer on the outer surface side. However, the subsequent coatability of the outer surface needs to be ensured, and a stripped lubricating film that is removed by alkali degreasing or the like is more advantageous in handling. Further, a rust-preventive oil can be applied to the inner and outer surfaces, and a lubricating oil can be applied during molding.

Alternatively, the resin layer of the present invention is formed only on one side of the inner surface, and another resin film is formed on the outer surface, preferably a resin film excellent in lubricity (moldability) and corrosion resistance (particularly corrosion resistance after processing). It can also be. Alternatively, the outer surface may be left plated (or plated and grounded), and may be directly coated.

[0033]

The following examples illustrate the invention and are not intended to limit the invention. In the examples, the amounts of plating, base treatment, and adhesion of the resin layer are all adhesion amounts per one surface.

Example 1 Double-sided Zn-13% Ni electroplated steel sheet
Both sides of the coating (coating weight 30 g / m ² ) were subjected to a coating type chromate treatment so that the Cr coating weight was 60 mg / m ² .

On one surface of the chromate-treated Zn—Ni alloy electroplated steel sheet, a thermosetting urethane-modified epoxy resin having a number average molecular weight of 30,000 was used as a base resin, and the resin solution (solvent: cyclohexanone) was prepared in the ratio shown in Table 1 below. A coating material in which at least one kind of pigment is dispersed is applied by a bar coater so that the amount of the resin layer after drying becomes 6 g / m ^2, and the coating is performed at 230 ° C. with 50 g / m ^2.
Baking for 2 seconds formed a pigment-containing resin layer.

Pigment Ni powder used : granular with an average particle diameter of 0.8 μm Al powder: flaky Ni-Al alloy powder with an average particle diameter of 13 μm: granular with an average particle diameter of 3 μm Iron phosphide: granular with a mean particle diameter of 6 μm Ferrosilicon : Granules having an average particle size of 4 μm The thus-prepared surface-treated steel sheet having a resin layer only on one side was subjected to an evaluation test for the following properties required for use in a fuel tank. In all cases, evaluations up to “「 ”are acceptable. Table 1 shows the test results together with the composition of the resin layer.

Test Method (1) Deteriorated Gasoline Corrosion Resistance (Inner Corrosion Resistance) Cup squeezing was performed under the following squeezing conditions so that the surface (resin surface) on which the resin layer of the test material was formed was the inner surface. Inside, 10 cc of aqueous solution of 3000 ppm formic acid and gasoline
20 cc and sealed (accordingly, the formic acid concentration in the test solution was 1000 ppm) and kept at 50 ° C. The evaluation was made as follows in the state of corrosion products (liquid turbidity) after 20 days.

Drawing conditions Blank diameter: 100 mm, punch diameter: 50 mm (5R), die diameter: 52.5 mm (5R), drawing height: 25 mm, use of lubricating oil, alkali degreasing after drawing.

Evaluation criteria ◎: almost no change;: about 10 to 40% of smearing seen from above; Δ: about 40 to 70% of smearing seen from above (observation of bottom surface is very difficult); × : Red rust floats on almost the whole liquid (observation of bottom and side surfaces is quite difficult), or peeling and swelling of inner resin from cut parts are observed.

(2) Weldability Two sheets of the test material were overlapped so that the resin surface came on the mating surface, then welded under the following conditions, and evaluated by microscopic observation of the welded section.

Welding conditions Pressure: 300 kgf, energization: 3 cycles, rest: 2 cycles, current: 13 kA, speed: 2.5 mpm.

Evaluation criteria ◎: good welding; ：: small blowholes, but no practical problem; Δ: blowholes; ×: unwelded portions.

(3) Formability For the sample squeezed under the same conditions as the test for the corrosion resistance of the deteriorated gasoline, the adhesion of the coating on the wall on the inner surface side of the squeezed film was determined as follows.
It was visually evaluated as follows from the state of peeling with the adhesive tape.

Evaluation criteria ◎: no peeling; ○: slight pigment adhesion on the tape; Δ: clear peeling on the tape; ×: peeling almost over the entire surface.

[0045]

[Table 1]

As can be seen from Table 1, in the comparative example where only the pigment A selected from Ni, Al and Ni-Al was present in the resin layer,
The internal corrosion resistance (degraded gasoline corrosion resistance) and moldability were good, but the weldability was insufficient, and the weldability was very poor unless Ni was included. On the other hand, when a part of the metal pigment A was changed to the pigment B (iron phosphide and / or ferrosilicon) according to the present invention while keeping the total amount of the pigment the same, good internal corrosion resistance and moldability were maintained. As it is
Weldability was improved, and a surface-treated steel sheet for a fuel tank was obtained in which the corrosion resistance to deteriorated gasoline, the weldability and the formability were highly balanced.

Example 2 Double-sided Zn-55% Al hot-dip coated steel sheet
Reactive chromate treatment was applied to both sides of the coating (coating weight: 60 g / m ² ) so that the Cr coating weight was 20 mg / m ² . The following pigment and silica (dry silica produced by a gas phase method) are dispersed in the following ratio in a resin solution (solvent: cyclohexanone) containing a thermosetting amine-modified epoxy resin having a number average molecular weight of 25,000 as a base resin. Paint on the one side of the above-mentioned chromate-treated plated steel sheet,
Was coated with a bar coater such that the coating weight of ~20g / m ^2, 20
The resin layer was formed by baking at 0 ° C. for 45 seconds.

Resin layer composition Amine-modified epoxy resin 60 parts by weight Ni powder (particle size: 0.8 μm) 10 parts by weight Al powder (particle size: 13 μm scale) 12 parts by weight Ferrosilicon (particle size: 4 μm particles) 8 parts by weight Silica ( 10 parts by weight The performance of the prepared surface-treated steel sheet was evaluated in the same manner as in Example 1, and the results are shown in Table 2 together with the adhesion amount of the resin layer. If the adhesion amount of the resin layer is less than 3 g / m ² , sufficient deterioration gasoline corrosion resistance cannot be obtained. If the adhesion amount exceeds 10 g / m ² , the resin layer becomes too thick and sufficient weldability is obtained. I can't.

[0049]

[Table 2]

(Example 3) Both surfaces of a double-sided electric Zn-plated steel sheet (coating weight: 50 g / m ² ) were subjected to immersion zinc phosphate treatment so as to have a coating weight of 1.5 g / m ² . Using the same amine-modified epoxy resin as used in Example 2 as a base resin, a paint was prepared in which the pigment particle size, the content of each pigment, and the total amount of pigment were changed as shown in Table 3. This paint is applied to one side of the above-mentioned immersion-type zinc phosphate-treated plated steel sheet so that the adhesion amount of the resin layer after drying is about 6 g / m ^2, and is applied at 240 ° C.
The resin layer was formed by baking for 80 seconds. The results of examining the performance of the surface-treated steel sheet prepared in the same manner as in Example 1 are also shown in Table 3.

[0051]

[Table 3]

As shown in Table 3, when the total amount of the pigment in the resin layer is less than 15% by weight, the weldability is insufficient, and when the total amount of the pigment exceeds 70% by weight, the pigment ratio in the resin layer is low. Is too high, and the pigment comes off during molding, resulting in insufficient moldability.

(Example 4) Both surfaces of a Zn-10% Fe alloyed hot-dip coated steel sheet (coating weight: 45 g / m ² ) were immersed in zinc phosphate treatment to give a coating weight of 1.5 g / m ^2. It was applied as follows. The same amine-modified epoxy resin as used in Example 2 was used as a base resin, and pigment A (at least one of Ni, Al, and Ni-Al alloy) and pigment B (at least one of iron phosphide or ferrosilicon) were used. ), The total amount of pigment is 30% of the resin weight.
The weight ratio of Pigment A / Pigment B is fixed to 100/0 to 0/10
Coatings were made with varying additions between zero. The paint was dried so that the amount of the resin layer after drying was about 5 g / m ² .
The resin was applied to one surface of the immersion-type zinc phosphate-treated plated steel sheet and baked at 240 ° C. for 80 seconds to form a resin layer. The results of examining the performance of the surface-treated steel sheet thus produced in the same manner as in Example 1 are shown in Table 4 together with the composition of the resin layer.

[0054]

[Table 4]

As shown in Table 4, when the weight ratio of pigment A / pigment B exceeds 90/10, the weldability decreases, and when the weight ratio is less than 30/70, the deterioration of the inner surface deteriorates. Gasoline corrosion resistance deteriorates. Considering the balance between weldability and corrosion resistance of deteriorated gasoline, a more preferable weight ratio of pigment A / pigment B is in the range of 80/20 to 40/60.

[0056]

Industrial Applicability According to the present invention, a fuel tank for an automobile, which is made of a Zn-plated steel plate which is relatively inexpensive and mass-produced, is excellent in deteriorated gasoline corrosion resistance, has high weldability, and has good formability. A surface-treated steel sheet for a fuel container suitable for use is provided, and a high-quality fuel tank that is easy for the user to use can be supplied at relatively low cost.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C09D 5/08 C09D 7/12 Z 7/12 163/00 163/00 175/04 175/04 B60K 15/02 A ( 72) Inventor Kenji Ikishima 4-53-3 Kitahama, Chuo-ku, Osaka City Inside Sumitomo Metal Industries Co., Ltd. (72) Inventor Kiyoyuki Fukui 4-5-33 Kitahama, Chuo-ku, Osaka Sumitomo Metal Industries Co., Ltd. (72) Inventor Shinya Hikino 1850 Minato, Wakayama-shi Sumitomo Metal Industries Co., Ltd. Wakayama Works (72) Inventor Toshiharu Oshiba 2-1-2 Oyodo-kita, Kita-ku, Osaka Japan F-term (Reference) 3D038 CA05 CA06 CB01 CC19 4D075 AE03 CA33 DA06 DB05 DC13 EA19 EB33 EC10 EC11 EC30 EC53 EC54 4J038 DB391 DB481 DG161 DL032 HA066 HA386 JC30 KA05 KA08 KA20 NA03 PB04 PB07 PC02 4K044 AA02 BA02 BA02 BA02 BA06 CA18 CA53 CA62

Claims (6)

[Claims] At least one surface of at least one surface of a zinc-based plated steel sheet is selected from one or more metal pigments A selected from Ni, Al and Ni-Al alloy, and iron phosphide and ferrosilicon. One or two pigments B are contained in an amount such that the weight ratio of pigment A / pigment B is in the range of 90/10 to 30/70 and the total amount of pigments is in the range of 15 to 70% by weight of the resin layer. A surface-treated steel sheet for a fuel container, characterized in that the thermosetting resin layer has an adhesion amount of 3 to 10 g / m ² . 2. The average particle size of each pigment is 0.5 to 15 μm.
The surface-treated steel sheet for a fuel container according to claim 1, wherein the range is m. 3. The surface-treated steel sheet for a fuel container according to claim 1, wherein the resin component in the resin layer is a modified epoxy resin. 4. In addition to a resin and a solvent, Ni, Al and Ni-
One or more metal pigments A selected from Al alloys
And a coating composition comprising one or two pigments B selected from iron phosphide and ferrosilicon,
The weight ratio of pigment A / pigment B is in the range of 90/10 to 30/70, and the total amount of pigment is 15 to 70 with respect to the solid content weight of the coating composition.
A coating composition for producing a surface-treated steel sheet for a fuel container, wherein the coating composition has an amount falling within the range of% by weight. 5. An average particle size of each pigment is 0.5 to 15 μm.
The coating composition according to claim 4, wherein m is in the range of m. 6. The coating composition according to claim 4, wherein the resin component in the resin layer is a modified epoxy resin.