JPH06146001A - Organic surface treating agent for aluminum-zinc alloy plated steel sheet and aluminum-zinc alloy plated steel sheet treated by this agent - Google Patents

Abstract

PURPOSE:To provide the Al-Zn alloy plated steel sheet having excellent alkaline resistance, black rust resistance and lubricity by applying the org. surface treating agent contg. a water-dispersible or water-soluble polyester resin or polyurethane resin to this steel sheet. CONSTITUTION:The org. surface treating agent for the Al-Zn alloy plated steel sheet is obtd. by incorporating a mixture composed of >=1 kinds of the water- dispersible or water-soluble polyester resin or polyurethane resin into this agent. This org. surface treating agent is applied to the surfaces of the Al-Zn alloy plated steel sheet subjected or not subjected to a chromate treatment at 0.3 to 4g/m<2> thickness by dry weight. The chromate treatment is preferably executed at <60mg/m<2> thickness in terms of chromic acid. A resin compsn. compounded with a chromium compd. of >=30% hexavalent chromium at 0.1 to 5% in terms of chromium oxide is preferably used in the case the steel sheet is not subjected to the chromate treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic surface treatment agent for an aluminum-zinc alloy plated steel sheet and an aluminum-zinc alloy plated steel sheet treated with the organic surface treatment agent.

[0002]

2. Description of the Related Art Aluminum-zinc alloy plated steel sheets are
Aluminum is 4 to 75% by weight, and most of the remainder is zinc, and it is third such as Si, Mg, Ce-La (Misch metal).
It is a steel plate plated with an alloy having a small amount of added components.

Currently, the commercialized products are a low aluminum-zinc alloy plated steel sheet plated with an alloy containing 4 to 10% by weight of aluminum, about 0.1% by weight of Mg and Ce-La, and the balance of zinc. And a high aluminum-zinc alloy plated steel sheet plated with an alloy containing 55% by weight of aluminum, 43.4% by weight of zinc and 1.6% by weight of Si. Regarding the corrosion resistance, the low aluminum-zinc alloy plated steel sheet has a corrosion resistance of 1.5 to 2 times, and the high aluminum-zinc alloy plated steel sheet has a corrosion resistance of 3 to 6 times as compared with the conventional hot-dip galvanized steel sheet. It has excellent properties. Due to its excellent corrosion resistance, it is widely used for building materials such as roofing materials and wall materials, materials for civil engineering products such as guardrails, soundproof walls, drains, bicycles, home appliances, industrial equipment, and substrates for coated steel sheets. It is used. However, in the aluminum-zinc alloy-plated steel sheet, since aluminum is mixed in the plating layer, particularly in the high-aluminum-zinc alloy-plated steel sheet, compared with the conventional galvanized steel sheet, the following problems occur. Exists.

(1) When it is placed in a wet environment in the as-plated state, it rusts, though less than the galvanized steel sheet. Rust is white on the galvanized steel sheet, but is gray to black on the aluminum-zinc alloy coated steel sheet, and the plating surface turns black, significantly reducing the commercial value. In order to solve this, conventionally, chromate treatment is performed on the aluminum-zinc alloy plating layer.

(2) Compared with the conventional hot-dip galvanized steel sheet, the plating film is hard, and when it is processed by roll forming or press forming, the lubricity is poor, the plating layer is broken, or frictional heat is generated. There is a phenomenon in which the plated layer is fused to the forming roll or the press die. As a result, the metal powder from the aluminum-zinc alloy plated steel sheet adheres to the forming roll and the press die, and the metal powder accumulates at the corners of the formed product to cause a seizure phenomenon, scratches or abrasion. The appearance changes due to defects such as. In order to solve this, conventionally, a lubricant such as oil or wax is applied to the surface of the aluminum-zinc alloy plated steel sheet. However, when using aluminum-zinc alloy plated steel sheet as a roofing material, there is a risk of slipping the foot during construction, and in consideration of the case where coating is applied on this, the lubricant must be completely removed at the time of shipping. I won't. In order to save such trouble of applying and removing the lubricant, a method of coating the surface of the aluminum-zinc alloy plated steel sheet with an acrylic resin has been proposed. In this method, the chromate treatment described in (1) can be replaced by adding chromic acid to the acrylic resin at the same time (Japanese Patent Publication No. 1-53353 and Japanese Patent Publication No. 4-26).
72).

[0006]

However, the use of aluminum-zinc alloy-plated steel sheets has expanded, and roof materials,
When it is used for building materials such as wall materials, civil engineering products such as guardrails, soundproof walls, drains, etc., it often comes into contact with materials containing alkali metals or alkaline earth metals such as slate and concrete. Elutes, the surface of the aluminum-zinc alloy plated steel sheet is significantly blackened due to the influence of alkali components, and the appearance is deteriorated.
If it is violent, it cannot be used.

An object of the present invention is to provide an aluminum-zinc alloy plated steel sheet having alkali resistance, black rust resistance (corrosion resistance) in a humid environment, and lubricity, and an organic coating treatment agent used therefor. It is provided.

[0008]

SUMMARY OF THE INVENTION The present invention comprises an aluminum-zinc alloy containing one or a mixture of two or more water-dispersible or water-soluble polyester resins or water-dispersible or water-soluble polyurethane resins. It is an organic surface treatment agent for plated steel sheets.

The present invention also provides a resin composition containing one or a mixture of two or more water-dispersible or water-soluble polyester resins or water-dispersible or water-soluble polyurethane resins in an amount of less than 60 mg / m ^{2 in} terms of chromic acid. An aluminum-zinc alloy-plated steel sheet characterized by being applied to the surface of an aluminum-zinc alloy-plated steel sheet chromated or not chromated at a thickness of 0.3 to 4 g / m ² dry weight. .

In the present invention, the resin composition contains a chromium compound having a hexavalent chromium content of 30% or more with respect to the total chromium content of 0.1 to 5% in terms of chromium oxide based on the resin content.
It is characterized by being blended.

Further, the present invention is characterized in that the aluminum-zinc alloy plated steel sheet is not subjected to chromate treatment.

Further, in the present invention, the resin composition comprises a resin having a glass transition temperature of 40 ° C. or more and a resin having a glass transition temperature of less than 40 ° C. in a dry weight ratio excluding chromium oxide thereof.
It is a mixture containing 5: 5 to 50:50.

Furthermore, the present invention provides the above resin composition,
Furthermore, 0.1 to 20 dry weight of olefin wax is used.
% Is included.

[0014]

The present inventors have earnestly studied, and were able to obtain a synthetic resin film which is used for an aluminum-zinc alloy plated steel sheet, which is excellent in alkali resistance, corrosion resistance in a wet environment, and lubricity. The properties of the synthetic resin film are related to the skeleton of the resin, the type of functional group, the film thickness, and the like.

According to the present invention, the polyester resin and the polyurethane resin have good alkali resistance, and the VO
From the viewpoint of C regulation and the like, it is preferably water-dispersible or water-soluble. The film thickness of the resin is preferably as thick as possible in consideration of alkali resistance, but the thicker the film, the longer it takes to dry and seize. If the drying and seizure are insufficient, film formation will be inadequate It has poor alkalinity, resulting in high cost. Therefore, the resin coating amount of the present invention is 0.3 g / m ² (same as dry weight and below), and 1 g / m of the conventional acrylic resin.
^Since it has a corrosion resistance effect equal to or higher than ² , it is not necessary to set it to 4 g / m ² or more when treating it on the same production line as plating and painting.

Polyester resin and polyurethane resin are
0.3 to 4 g / m in the sense that it has a coating film lubricity equal to or higher than that of acrylic resin, covers the surface of an aluminum-zinc alloy plated steel sheet, and completely forms a film.
The range is ² , and preferably 0 .. from the viewpoint of performance and cost.
It may be 8 to 1.5 g / m ² . Furthermore, for special deep drawing applications, it is preferable to add 0.1 to 20% by dry weight of a polyolefin wax to the above polyester resin or polyurethane resin coating in order to facilitate its processability. If the amount of the polyolefin wax added is 0.1% or less, the effect is small, and if it is more than 20%, the workability is improved, but if it exceeds 20%, the corrosion resistance and alkali resistance are deteriorated.

Chromate treatment is necessary for corrosion resistance. As a chromate treatment method, aluminum-
There is a method of applying a polyester resin or a polyurethane resin coating after chromate treatment on a zinc alloy plated steel sheet, and a method of incorporating hexavalent chromium in these resins. Assuming a real line, after the chromate treatment on the aluminum-zinc alloy plated steel sheet, in the method of applying a resin coating, the temperature of the steel strip rises due to the drying after the chromate treatment, so it is very difficult to control the application of the resin. Become.
Therefore, the method of containing hexavalent chromium in the resin is preferable. Hexavalent chromium in the resin is reduced to 1 part trivalent chromium during seizure. The ratio of hexavalent chromium in the resin of the present invention to the total chromium is preferably 30% or more. In the present invention, when it is particularly necessary to prevent the elution of hexavalent chromium, it is possible to use a reducing agent such as glycol to reduce the proportion of hexavalent chromium in the resin coating to 30%. The ratio of the chromium compound added to the resin is preferably 0.1 to 5% in terms of CrO _{3 with} respect to the solid content of the resin. CrO
_{If 3} is less than 0.1%, sufficient corrosion resistance is not exhibited.
On the other hand, if it exceeds 5%, the alkali resistance is lowered and the stability of the resin composition is deteriorated. Examples of the chromium compound used in the present invention include CrO ₃ , K ₂ CrO ₄ , and K ₂ C.
There is no particular limitation as long as it is a hexavalent chromium compound such as r ₂ O ₇ .

In order to further complete the chromate treatment, the aluminum-zinc alloy-plated steel sheet may be subjected to chromate treatment and then coated with a polyester resin or polyurethane resin containing hexavalent chromium in the above addition range. With this method, corrosion resistance can be improved without lowering alkali resistance. The chromate treatment of the base used at this time is preferably less than 60 mg / m ^{2 in} terms of CrO ₃ . At 60 mg / m ² or more, the coating looks yellow and the appearance is significantly impaired.

The polyester resin and the polyurethane resin used in the present invention have different resin coating hardness depending on their types. The higher the coating hardness, the better the lubrication performance on the flat surface, but when processed, fine cracks are generated in the processed part, so the alkali resistance and corrosion resistance in the processed part deteriorate. Therefore, in the present invention, the glass transition temperature (Tg)
Is as high as 80-40 ° C, and the resin and Tg with high coating hardness are
It is preferable to mix and use a resin having a low coating hardness of less than 40 to −10 ° C. in a dry weight ratio of 95: 5 to 50:50. In general, a resin having a low Tg is inferior in alkali resistance, corrosion resistance and lubricity on a flat surface, but this makes a resin film excellent in alkali resistance, corrosion resistance and lubricity on a flat surface portion and a processed portion.

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Examples 1 to 10 As an aluminum-zinc alloy plated steel sheet not subjected to chromate treatment, the plate thickness is 0.6 mm and the composition of the plating layer is Al.
= 55%, Zn = 43.4%, Si = 1.6% (all are weight%), and the amount of plating adhered on one side was 75 g / m ² . The size of the test piece is 250 mm x 50 mm for the hat forming test with beads, and 15 for other tests.
0 mm × 75 mm was used.

On the other hand, the resin composition was prepared by adding water to 250 g of a polyester resin or polyurethane resin having a glass transition temperature shown in Table 1 and 2.5 g of chromium oxide containing 50% of hexavalent chromium with respect to the total chromium. The amount was 1 kg, and this was dipped for 30 seconds in a Pulcleaner manufactured by Nippon Parker Rising Co., Ltd. to prepare an aqueous resin solution or an aqueous resin dispersion. A bar coater No. was formed on the surface of the aluminum-zinc alloy-plated steel sheet obtained by degreasing this resin aqueous solution or resin water dispersion.
No. 5 to No. 20 were used to apply a dry coating amount of 2 g / m ² . Immediately thereafter, the film was placed in a hot air drying oven at 500 ° C. for 5 seconds to form a dry film. The plate temperature at this time was 70 ° C. This was cooled to obtain a test plate. Incidentally, the film thickness was confirmed to be ² g / m ² by measuring the weight of the test piece before and after coating.

[0023]

[Table 1]

The obtained test pieces were tested for workability, corrosion resistance, alkali resistance, corrosion resistance and alkali resistance of the processed part, and color tone of the coating. The results are shown in Table 2.

Comparative Examples 1 to 3 Acrylic resin (1) shown in Table 1 as a resin composition
(Chuo Rika Kogyo Co., Ltd., trade name ES-20), acrylic-styrene resin (Asahi Kasei Co., Ltd., trade name Polytron F-2000) and acrylic resin (2) (Toyobo Co., Ltd. product The name Toughtic FC-490) was used. The results of measuring the glass transition temperature of these resins are
The results are shown in Table 1. Example 1 using these resins
The same method was used to obtain test pieces of the same size, and the same test was performed. The results are shown in Table 2.

[0026]

[Table 2]

Next, the test method will be described. This test method was also used in the following examples and comparative examples.

(1) Workability Using the beaded hat forming tester 1 shown in FIG.
A 0 mm × 50 mm test piece 11 is inserted between the table 3 and the presser foot 4 as shown in FIG. 1, and the presser foot 4 is lowered to hold the test piece 11 and press the punch 2 at a speed of 70 mm / sec for 43 m.
The test piece 11 was slid by the bead portion 5 of the base 3 while being raised to form a convex portion on the test piece 11. 2 is a sectional view of the tester 1 and the test piece 11 after processing, and FIG. 3 is a perspective view of the test piece 11 after molding. The test piece is evaluated by visually observing the surface of the test piece and using the following five-point method.

5 galling and no pick-up on resin and metal 4 galling occurs slightly, resin and metal pickup 5 mg or less 3 galling occurs slightly, resin and metal pickup 5-10 mg 2 galling occurs considerably, resin and metal Pickup of 100 mg 1 Processed part broke and could not be processed (2) Corrosion resistance Salt spray test with 5% saline solution 35 ° C x 400 hours (JIS Z 2371) 5 step evaluation by visual inspection of test piece 5 White rust did not occur 4 White Rust occurrence rate of less than 5% 3 White rust occurrence rate of 5 to 10% 2 White rust occurrence rate of 10 to 50% 1 White rust occurrence rate of 50% or more (3) Alkali resistance 1% Sodium hydroxide aqueous solution immersion test 30 ° C x 30
5 Visual evaluation of the test piece 5 Black rust is not generated 4 Black rust is slightly generated, but it is not noticeable 3 Black rust is generated, slightly conspicuous 2 Black rust is generated, and the whole is black 1 Black rust is generated, and the coating is very black and some of the coating is removed. (4) Corrosion resistance of the processed part A 150 mm x 75 mm test piece was tested using a bending tester manufactured by Yasuda Mfg. A U-shaped test piece 12 of R = 5 mm was prepared, 5% saline was sprayed at 35 ° C. for 400 hours on the outer side of the bending surface (the portion indicated by the arrow 13 in FIG. 3), and the bending surface was visually inspected and evaluated in 5 grades. To do.

The rating is the same as the corrosion resistance of (2).

(5) Alkali resistance of processed part A similar test piece was prepared in the same manner as in (4), the bending surface was immersed in a 0.5% aqueous sodium hydroxide solution at 30 ° C. for 15 minutes, and the bending surface was visually observed. It is evaluated in 5 steps.

The rating is the same as the alkali resistance of (3).

(6) Color tone of coating film The color difference from the steel sheet as the base is visually observed and evaluated on a scale of 5 to 5.

5 Same color as base steel plate 4 Slightly different color from base steel plate 3 Appears to be slightly yellow 2 Appears to be quite yellow 1 Appears to be yellow From Examples 1 to 10 and Comparative Examples 1 to 3, polyester-based and polyurethane-based It can be seen that the one using the resin is superior in alkali resistance to the non-processed part and the processed part than the one using the conventional acrylic resin.

Example 11 As the resin component of the resin composition, 95: polyester resin (1) (having a glass transition temperature of 40 ° C. or higher) and polyester resin (2) (having a glass transition temperature of less than 40 ° C.) shown in Table 1 were used:
Examples 1 to 10 except that the mixture in the ratio of 5 was used.
In the same manner as above, a test piece of the same size was obtained and the same test was performed. The results are shown in Table 3.

Example 12 As resin components of the resin composition, the polyester resin (1) (having a glass transition temperature of 40 ° C. or higher) and the polyester resin (2) (having a glass transition temperature of less than 40 ° C.) shown in Table 1 were 50:
Examples 1 to 1 except that a mixture of 50 parts was used.
A test piece of the same size was obtained in the same manner as 0, and the same test was performed. The results are shown in Table 3.

Example 13 As the resin component of the resin composition, polyester resin (1) (glass transition temperature of 40 ° C. or higher) and polyester resin (2) (glass transition temperature of less than 40 ° C.) of Table 1 were 40:
Examples 1 to 1 except that a mixture of 60 parts was used.
A test piece of the same size was obtained in the same manner as 0, and the same test was performed. The results are shown in Table 3.

Example 14 Polyester resin (2) (glass transition temperature of less than 40 ° C.), polyester resin (3) (glass transition temperature of 40 ° C. or higher) and polyurethane resin (1) as resin components of the resin composition ) (Glass transition temperature of 40 ° C or higher) and 3
A test piece of the same size was obtained in the same manner as in Examples 1 to 10 except that the mixture of 0:40:30 was used, and the same test was performed. The results are shown in Table 3.

[0039]

[Table 3]

From the results of Examples 1 to 14, it was found that the alkali resistance was slightly inferior when using only the resin having a glass transition temperature of less than 40 ° C. and the proportion thereof was 50% or more, and the resistance to the processed portion was high. On the contrary, the alkalinity is inferior when using only the resin having a glass transition temperature of 40 ° C. or higher. However, if a resin with a glass transition temperature of 40 ° C or higher is used,
Resin having a glass transition temperature of less than 40 ° C.
It can be seen that the alkali resistance of the unprocessed part and the processed part is improved by mixing 50%.

Examples 15 to 17 The polyester resin (1) shown in Table 1 was used as the resin component of the resin composition, and the ratio of hexavalent chromium to the total chromium in the chromium oxide added thereto was 30% or more. The same test was performed by making test pieces of the same size in the same manner as in Examples 1 to 10 except that the above was changed. The results are shown in Example 1.
The results are shown in Table 4.

Comparative Example 4 As the resin component of the resin composition, the polyester resin (1) shown in Table 1 was used, and the ratio of hexavalent chromium to the total chromium in the chromium oxide added thereto was less than 30% (20%). Other than the above, test pieces of the same size were made in the same manner as in Examples 1 to 10 and the same test was performed. The results are shown in Table 4.

[0043]

[Table 4]

From Table 4, it can be seen that when the ratio of hexavalent chromium to the total chromium is less than 30%, the corrosion resistance of the non-processed part and the processed part is poor.

Examples 18 and 19 The polyester resin (1) shown in Table 1 was used as the resin of the resin composition, and the amount of chromium oxide added thereto was 0.75 to 12.5 g (resin solid content ratio) shown in Table 5. 0.3 ~ 5
%) Except that the test pieces of the same size were made in the same manner as in Examples 1 to 10 and the same test was performed. The results are shown in Table 5 together with the results of Example 1. Further, in order to examine the stability of the resin composition containing chromium oxide, the prepared resin composition was allowed to stand for one week, but there was no change in the resin composition.

Comparative Examples 5 and 6 The polyester resin (1) shown in Table 1 was used as the resin of the resin composition, and the amount of chromium oxide added thereto was 0.75 g and 12.5 g shown in Table 5 (resin solid content ratio). 0.3
% And more than 5%).
A test piece of the same size was made in the same manner as 10 and the same test was performed. The results are shown in Table 5. In addition, Example 18,
The prepared resin composition was allowed to stand for 1 week in order to investigate the stability of the resin composition in the same manner as in 19. as a result,
In Comparative Example 5 in which the amount of chromium oxide added was small, there was no change in the resin composition, but in Comparative Example 6 in which the amount of chromium oxide added was large, precipitation of chromium oxide occurred. Furthermore, the resin composition containing 10% or more of chromium oxide in terms of resin solid content gelled after 1 week and became unusable.

[0047]

[Table 5]

From this, the resin composition containing less than 0.3% or more than 5% of chromium oxide is inferior in corrosion resistance to the non-processed part, and the perchrome resin containing more than 5% of chromium oxide is not treated on the unprocessed part. It can be seen that the alkali resistance of the processed part and the corrosion resistance of the processed part are poor, and the color tone of the coating is poor. Further, when the amount of chromium oxide added is large, precipitation tends to occur with the passage of time, but when it is 5% or less, precipitation does not occur even after 1 week, and it is understood that the resin composition is stable.

Examples 20 and 21 The polyester resin (1) shown in Table 1 was used as the resin of the resin composition, and the film thickness of the resin applied to the test piece was 0.3 to 4 g / m ² as shown in Table 6. Other than the above, Examples 1 to 1
A test piece of the same size was made in the same manner as 0, and the same test was performed. The results are shown in Table 6 together with the results of Example 1.

Comparative Examples 7 and 8 The polyester resin (1) shown in Table 1 was used as the resin of the resin composition, and the film thickness of the resin applied to the test piece was less than 0.3 g / m ² shown in Table 6 (0. 1 g / m ² ) or 4 g / m
Examples 1 to 1 except that the thickness is more than ² (5 g / m ² ).
A test piece of the same size was made in the same manner as 0, and the same test was performed. The results are shown in Table 6.

[0051]

[Table 6]

From this, when the film thickness is less than 0.3 g / m ² , the unprocessed part and the processed part are inferior in corrosion resistance and the unprocessed part and the processed part are resistant to alkali, and the film thickness is more than 4 g / m ^2. In this case, it is understood that the alkali resistance of the unprocessed part and the processed part is inferior, and the color tone of the coating is slightly poor.

Examples 22 and 23 The polyester resin (1) shown in Table 1 was used as the resin of the resin composition, and the olefin wax (manufactured by Sanyo Kasei Co., Ltd., trade name Permarin RN) is shown in Table 7. A test piece of the same size was made in the same manner as in Examples 1 to 10 except that 0.1 to 20% of the resin solid content was added, and the same test was performed. The results are shown in Table 7.

Comparative Example 9 As the resin of the resin composition, the polyester resin (1) shown in Table 1 was used, and an olefin wax (manufactured by Sanyo Chemical Industry Co., Ltd., trade name Permarin RN) is shown in Table 7 as a resin solid. By the same method as in Examples 1 to 10 except that an amount of more than 20% (25%) was added in proportion, a test piece of the same size was made and the same test was performed. The results are shown in Table 7 together with the results of Example 1 in which the olefin wax was not added.

[0055]

[Table 7]

From this, it is understood that the workability is slightly improved by the addition of the wax, but the alkali resistance of the non-processed part and the processed part is deteriorated when the addition amount exceeds 20%.

Examples 24-26 Aluminum-zinc alloy-plated steel sheets having a thickness of less than 60 mg / m ² shown in Table 8 and a chromate treatment applied to the test pieces (the conditions for aluminum-zinc alloy plating are Examples 1-10).
Same as the above), using the polyester resin (1) of Table 1 as the resin of the resin composition, a test piece of the same size was made in the same manner as in Examples 1 to 10 and the same test was performed. The results are shown in Table 8 together with the results of Example 1 in which the chromate treatment was not performed.

Comparative Example 10 An aluminum-zinc alloy-plated steel sheet (aluminum-zinc alloy plating conditions are the same as those of Examples 1 to 10) obtained by subjecting a test piece to a chromate treatment of 60 mg / m ² shown in Table 8 was performed. Using the polyester resin (1) of Table 1 as the resin of the resin composition, test pieces of the same size were made in the same manner as in Examples 1 to 10 and the same test was performed. The result is
It shows in Table 8 with the result of Example 1 which does not carry out a chromate treatment.

[0059]

[Table 8]

From this, it can be seen that the corrosion resistance or alkali resistance of the processed part is slightly deteriorated if the thickness of the chromate treatment is small or not. On the contrary, it can be seen that the color tone of the coating deteriorates when the thickness of the chromate treatment is 60 mg / m ² or more.

[0061]

As described above, according to the present invention, by a simple method of coating with a resin composition containing a polyester-based resin or a polyurethane-based resin, it has excellent processability, alkali resistance and corrosion resistance, and its color tone is also conventional. An aluminum-zinc alloy plated steel sheet equivalent to or better than the product can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hat testing machine with beads 1 for testing the workability of a test piece 11.

FIG. 2 is a cross-sectional view showing a state where a test piece 11 is processed by the beaded hat tester 1.

FIG. 3 is a perspective view of a test piece 11 processed and molded by the beaded hat tester 1.

FIG. 4 is a cross-sectional view of a test piece 12 for testing the corrosion resistance of the processed part and the alkali resistance of the processed part.

[Explanation of Codes] 1 Hat tester with bead 11 Test piece for workability 12 Test piece for corrosion resistance of processed portion and alkali resistance of processed portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiko Hobo 1850 Minato, Wakayama, Wakayama Sumitomo Metal Industries Co., Ltd.Wakayama Works (72) Hiroshi Fukudome 1850, Minato, Wakayama, Wakayama Sumitomo Metal Industries, Ltd. Wakayama Works (72) Inventor Naotaka Ueda 1850 Minato, Wakayama, Wakayama Sumitomo Metal Industries, Ltd. Wakayama Works

Claims (6)

[Claims] 1. A water-dispersible or water-soluble polyester resin or a water-dispersible or water-soluble polyurethane resin
An organic surface treatment agent for an aluminum-zinc alloy-plated steel sheet, which comprises one kind or a mixture of two or more kinds. 2. A water-dispersible or water-soluble polyester resin or a water-dispersible or water-soluble polyurethane resin.
0.3 to 4 g / m on the surface of an aluminum-zinc alloy-plated steel sheet that is chromated with a thickness of less than 60 mg / m ^{2 in} terms of chromic acid, or is not chromated with a resin composition containing one or a mixture of two or more. An aluminum-zinc alloy-plated steel sheet, which is applied in a dry weight thickness of ² . 3. The resin composition contains a chromium compound having a hexavalent chromium content of 30% or more based on the total chromium content in an amount of 0.1 to 5% in terms of chromium oxide based on the resin content. The aluminum according to claim 2, wherein
Zinc alloy plated steel sheet. 4. The aluminum-zinc alloy plated steel sheet according to claim 3, wherein the aluminum-zinc alloy plated steel sheet is not subjected to chromate treatment. 5. The glass transition temperature of the resin composition is 40.
A resin having a glass transition temperature of less than 40 ° C.
The dry weight ratio excluding the chromium oxide is 95: 5 to 5
It is a mixture containing in the ratio of 0:50, The aluminum-zinc alloy plated steel plate in any one of the Claims 2-4 characterized by the above-mentioned. 6. The aluminum-zinc alloy according to any one of claims 2 to 5, wherein the resin composition further contains 0.1 to 20% by dry weight of an olefin wax. Plated steel sheet.