WO2016121277A1 - Method for producing surface-treated steel plate - Google Patents

Abstract

Provided is a method for producing a surface-treated steel plate (1), said method comprising: a phosphate compound layer formation step in which a tin-plated steel sheet (10) obtained by plating a steel plate (11) with tin plating (12) is immersed in an immersion treatment liquid containing phosphate ions without performing electrolytic treatment in order to perform immersion treatment and thereby form a phosphate compound layer (20) on the tin-plated steel plate (10); and an aluminum-oxygen compound layer formation step in which an aluminum-oxygen compound layer (30) is formed on the phosphate compound layer (20) by electrolytic treatment using an electrolytic treatment liquid that contains aluminum.

Description

Manufacturing method of surface-treated steel sheet

The present invention relates to a method for producing a surface-treated steel sheet.

For base materials used in the fields of metal containers, home appliances, building materials, vehicles, airplanes, etc., methods for chromating the surface are known, but non-chromium surface treatments have been developed to replace such chromating. Yes. For example, Patent Document 1 discloses a non-chromium surface treatment technique for forming a metal oxygen compound film containing aluminum on the surface of a base material by cathodic electrolysis using an electrolytic treatment liquid containing aluminum ions. ing.

JP 2006-348360 A

However, in the prior art described in Patent Document 1, when the surface-treated steel sheet is used in a food can or the like and stored for a long period of time, it reacts with sulfur contained in the food or drink and the surface turns black. There is a problem that changes occur.

An object of the present invention is to provide a surface-treated steel sheet capable of effectively suppressing sulfide blackening.

The present inventors formed a phosphate compound layer containing tin phosphate on a tin-plated steel sheet by immersion treatment using an immersion treatment solution containing phosphate ions, and aluminum was formed on the phosphate compound layer. It has been found that the above object can be achieved by forming an aluminum oxygen compound layer containing an oxygen compound as a main component, and the present invention has been completed.

That is, according to the present invention, the tin-plated steel sheet obtained by performing tin plating on the steel sheet is subjected to an immersion treatment in which the tin-plated steel sheet is immersed in an immersion treatment solution containing phosphate ions without performing an electrolytic treatment. A phosphoric acid compound layer forming step for forming a phosphoric acid compound layer containing 0.4 to 10 mg / m ² as the amount of phosphorus on the plated steel sheet, and an electrolytic treatment liquid containing aluminum on the phosphoric acid compound layer were used. An aluminum oxygen compound layer forming step of forming an aluminum oxygen compound layer by electrolytic treatment is provided.

In the production method of the present invention, it is preferable to use a treatment liquid having a pH of 1.0 to 4.0 as the immersion treatment liquid in the phosphate compound layer forming step.
In the production method of the present invention, it is preferable that the temperature of the immersion treatment liquid when dipping the tin-plated steel sheet is 35 to 55 ° C. in the phosphate compound layer forming step.
In the production method of the present invention, the total amount of aluminum contained in each layer formed on the tin-plated steel sheet is preferably 3 to 40 mg / m ² .
In the manufacturing method of this invention, it is preferable to use the processing liquid whose phosphoric acid content is 0.55 g / L or less in the amount of phosphorus in the said aluminum oxygen compound layer formation process as said electrolytic processing liquid.
In the manufacturing method of this invention, it is preferable to use the process liquid which does not contain F ion substantially as said electrolytic treatment liquid in the said aluminum oxygen compound layer formation process.
In the production method of the present invention, as the tin-plated steel sheet, the steel sheet, a tin alloy layer formed on the steel sheet, and a tin amount formed on the tin alloy layer is 0.5 g / m ² or more. It is preferable to use a tin-plated steel sheet comprising a tin-plated layer.

According to the present invention, a phosphoric acid compound layer having a phosphorus amount of 0.4 to 10 mg / m ² is formed on a tin-plated steel sheet by dipping treatment using a dipping treatment liquid containing phosphate ions. By forming the aluminum oxygen compound layer on the phosphate compound layer, the aluminum oxygen compound layer contains phosphate. And the surface treatment steel plate by which the blackening of the surface by sulfur is prevented by the effect | action of the phosphate in an aluminum oxygen compound layer can be provided.

It is sectional drawing which shows the structure of the surface treatment steel plate which concerns on embodiment of this invention. It is a conceptual diagram which shows a mode that a phosphoric acid compound layer and an aluminum oxygen compound layer are formed on a tin plating steel plate. It is a figure which shows an example of the metal container formed using the surface treatment steel plate which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a configuration of a surface-treated steel sheet 1 according to an embodiment of the present invention. First, the surface-treated steel sheet 1 of the present embodiment is obtained by immersing a tin-plated steel sheet 10 in which a tin-plated layer 12 is formed on a steel sheet 11 in an immersion treatment solution containing phosphate ions. Then, the phosphoric acid compound layer 20 is formed while dissolving a part of the tin plating layer 12, and then an electrolytic treatment is performed in an electrolytic treatment solution containing Al ions, so that phosphoric acid is deposited on the phosphoric acid compound layer 20. It is obtained by forming the aluminum oxygen compound layer 30 while dissolving a part of the compound layer 20.

The surface-treated steel sheet 1 of the present embodiment is not particularly limited, but can be used as a member such as a can container or a can lid, for example. When the surface-treated steel sheet 1 is used as a member such as a can container or a can lid, the surface-treated steel sheet 1 is used as it is (for non-coating applications in which a coating layer is not formed on the surface), and an uncoated can container or can As shown in FIG. 1, a cover layer made of an organic material may be formed on the aluminum oxygen compound layer 30 of the surface-treated steel sheet 1 and then formed into a can container or a lid. .

<Tin-plated steel sheet 10>
The tin-plated steel sheet 10 that is the base material of the surface-treated steel sheet 1 of the present invention is obtained by performing tin plating on the steel sheet 11 and forming a tin-plated layer 12 on the steel sheet 11.

The steel plate 11 for performing the tin plating is not particularly limited as long as it is excellent in drawing workability, drawing ironing workability, workability of drawing and bending back work (DTR), for example, Further, a hot-rolled steel sheet based on an aluminum killed steel continuous cast material, a cold-rolled steel sheet obtained by cold rolling these hot-rolled steel sheets, or the like can be used. Alternatively, as the steel plate 11 for performing tin plating, a nickel plating layer is formed on the above-described steel plate, and this is heated and thermally diffused to form a nickel-iron alloy layer between the steel plate and the nickel plating layer. By doing so, a nickel-plated steel sheet with improved corrosion resistance may be used. Further, when the nickel plating layer is formed in a granular shape, the adhesion of the coating layer can be enhanced by the anchor effect.

The method for applying tin plating to the steel plate 11 is not particularly limited, and examples thereof include a method using a known ferrostan bath, halogen bath, sulfuric acid bath, or the like. The method of performing nickel plating is not particularly limited, and a known Watt bath made of nickel sulfate and nickel chloride can be used. However, when forming a nickel plating layer in a granular form, a bath composition made of nickel sulfate and ammonium sulfate is used. Is preferred. Further, in the present embodiment, the tin-plated steel sheet 10 obtained by performing tin plating in this way is subjected to a rapid cooling process (reflow process) after being heated to a temperature higher than the melting temperature of tin, whereby the steel sheet 11 and tin A tin-iron alloy layer may be formed between the plating layer 12 and the plating layer 12. In the present embodiment, by performing this reflow treatment, the obtained tin-plated steel sheet 10 has a tin-iron alloy layer and a tin-plated layer 12 formed in this order on the steel sheet 11, and has corrosion resistance. improves. When a nickel plating layer is present on the base, a tin-nickel or tin-nickel-iron alloy can also be formed between the steel plate 11 and the tin plating layer 12 by this reflow process.

In the present embodiment, the tin-plated steel sheet 10 obtained as described above is usually oxidized on the surface by oxygen, and an oxide film layer made of SnO _x (x = 1 to 3) is formed on the surface. The oxide film layer made of SnO _x tends to reduce the adhesion of the phosphoric acid compound layer 20 formed on the tin-plated steel sheet 10 when the film amount is too large, while the tin-plated steel sheet when the film amount is too small. Since 10 tends to be blackened easily, it is desirable to adjust to an appropriate film amount. Therefore, in this embodiment, you may perform the process which removes a part or all of the oxide film layer of a surface, and adjusts the film quantity of an oxide film layer with respect to the tin plating steel plate 10. FIG. For example, an aqueous carbonate carbonate solution such as sodium carbonate or sodium hydrogencarbonate is used for the tin-plated steel sheet 10 under the conditions of a current density of 0.5 to 20 A / dm ² and an energization time of 0.1 to 1.0 seconds. You may perform the process which removes the oxide film layer of the surface of the tin-plated steel plate 10 by performing at least one of a cathodic electrolysis process and an anodic electrolysis process. Moreover, you may perform the process which removes the oxide film layer of the surface of the tin-plated steel plate 10 by performing the process which immerses the tin-plated steel plate 10 in acidic aqueous solutions, such as hydrochloric acid. In this case, the time for immersing the tin-plated steel sheet 10 in the acidic aqueous solution is preferably 2 seconds or less. By setting the time for immersing the tin-plated steel sheet 10 in the acidic aqueous solution to the above range, the oxide film layer made of SnO _x can be efficiently removed while suppressing the dissolution of the metal tin portion of the tin-plated layer 12.

The thickness of the tin plating layer 12 formed on the steel plate 11 is not particularly limited, and may be appropriately selected according to the intended use of the surface-treated steel plate 1 to be manufactured. However, the tin amount is preferably 0.5 g / m ^2. Above, more preferably 0.5 to 15 g / m ² . Also when the nickel plating layer is provided, the thickness of the nickel plating layer is not particularly limited, and the thickness of the nickel plating layer is preferably 0.01 to 15 g / m ² in terms of nickel amount. When the nickel plating is granular, the average particle diameter of the granular nickel is preferably 0.01 to 0.7 μm.

The total thickness of the tin-plated steel sheet 10 is not particularly limited and may be appropriately selected depending on the intended use of the surface-treated steel sheet 1 to be manufactured, but is preferably 0.07 to 0.4 mm.

<Phosphate compound layer 20>
The phosphoric acid compound layer 20 is a layer containing tin phosphate, and the above-described tin-plated steel sheet 10 is immersed in an immersion treatment solution that is an aqueous solution containing phosphate ions (hereinafter referred to as “immersion treatment”). .). In the present embodiment, when the tin-plated steel sheet 10 is immersed in the immersion treatment liquid, electrolytic treatment (preparing the tin-plated steel sheet 10 and the counter electrode and energizing them in the immersion treatment liquid) is not performed.

In the present embodiment, by performing the above immersion treatment on the tin-plated steel sheet 10, as shown in the left diagram of FIG. 2, tin is dissolved from the tin-plated steel sheet 10 and divalent tin ions (Sn ²⁺ ). Will occur.

FIG. 2 is a conceptual diagram showing how the phosphoric acid compound layer 20 and the aluminum oxygen compound layer 30 are formed on the tin-plated steel sheet 10. In the left figure in FIG. 2, an example of a reaction when the tin-plated steel sheet 10 is immersed in an immersion treatment liquid containing phosphate ions is shown. 2, cathodic electrolysis treatment for forming the aluminum oxygen compound layer 30 is performed on tin phosphate such as Sn ₃ (PO ₄ ) ₂ formed as the phosphate compound layer 20. I showed the situation. In the right figure in FIG. 2, on the tin-plated steel sheet 10, tin phosphate compound as the phosphoric acid compound layer 20 and AlPO _4, and aluminum oxygen compound layer 30 as AlPO ₄ and _{Al 2 O} 3 · nH 2 _O and It is a figure which shows a mode that Al (OH) ₃ was formed. In this embodiment, AlPO ₄ is contained in both the phosphate compound layer 20 and the aluminum oxygen compound layer 30.

In the present embodiment, as shown in FIG. 2, tin ions Sn ²⁺ generated from the tin-plated steel sheet 10 react with phosphate ions or the like in the immersion treatment liquid, and phosphoric acid such as Sn ₃ (PO ₄ ) _2. It is deposited on the tin-plated steel sheet 10 as tin. Further, tin ions Sn ²⁺ generated from the tin-plated steel sheet 10 are deposited on the tin-plated steel sheet 10 as tin oxide (SnO _x ).

In the immersion treatment liquid containing phosphoric acid, phosphoric acid (H ₃ PO ₄ ), primary phosphate ions (H ₂ PO ₄ ⁻ ), and secondary phosphate ions (HPO ₄ ) are selected depending on the pH of the aqueous solution. ^2- ), tertiary phosphate ion (PO ₄ ³⁻ ), phosphorous acid (H ₂ PHO ₃ ), phosphite ion (HPHO ₃ ⁻ , PHO ₃ ²⁻ ) and the like. In the present embodiment, by immersing the tin-plated steel sheet 10 in such an immersion treatment solution, as shown in the left diagram of FIG. 2, the surface of the tin-plated layer 12 is formed near the surface of the tin-plated layer 12. The formed tin oxide is reduced to produce tin ions Sn ²⁺ , and hydroxide ions (OH ⁻ ) are produced to raise the pH. In accordance with this increase in pH, phosphoric acid (H ₃ PO ₄ ), primary phosphate ions (H ₂ PO ₄ ⁻ ), phosphorous acid (H ₂ PHO ₃ ) and phosphorous acid are contained in the immersion treatment solution. It is considered that acid ions (HPHO ₃ ⁻ , PHO ₃ ²⁻ ) are mainly present. At this time, tin ions Sn ²⁺ in the immersion treatment liquid are combined with the above-described primary phosphate ions (H ₂ PO ₄ ⁻ ) and phosphite ions (HPHO ₃ ⁻ , PHO ₃ ²⁻ ) and the like. Deposited on the tin-plated steel sheet 10, the phosphoric acid compound layer 20 is formed.

In the present embodiment, the surface-treated steel sheet 1 obtained by forming the phosphate compound layer 20 containing tin phosphate by the above-described immersion treatment is excellent in resistance to sulfur blackening. Furthermore, in this embodiment, when the coating layer 40 made of an organic material is formed on the surface of the surface-treated steel sheet 1 by forming the phosphate compound layer 20 containing tin phosphate by the above-described immersion treatment, The adhesion of the layer 40 is excellent. That is, when the aluminum oxygen compound layer 30 is directly formed on the surface-treated steel sheet 1, when the coating layer 40 is formed by baking coating or the like, the oxide film that covers the tin-plated layer 12 of the surface-treated steel sheet 1 by the heat of baking A layer grows, and the aluminum oxygen compound layer 30 and the covering layer 40 may peel from the oxide film layer. On the other hand, by forming the phosphoric acid compound layer 20 described above, it is possible to suppress the growth of the oxide film layer that covers the tin plating layer 12 when forming the coating layer 40, and as a result, the surface of the surface-treated steel sheet 1. The adhesiveness of the coating layer 40 to be formed can be improved.

Furthermore, in this embodiment, the favorable aluminum oxygen compound layer 30 is formed on the phosphate compound layer 20 by forming the phosphate compound layer 20 by the immersion treatment as described above. That is, the present inventors performed immersion treatment on the tin-plated steel sheet 10, and as described above, primary phosphate ions (H ₂ PO ₄ ⁻ ) and phosphite ions (HPHO ₃ ⁻ , PHO ₃ ^{2). -} ) And the like react with tin ions to form tin phosphate, and the chemical bonding state and surface form of this tin phosphate are used in the electrolytic treatment liquid used when the aluminum oxygen compound layer 30 described later is formed by electrolytic treatment. The knowledge that it becomes easy to dissolve was obtained. And based on such knowledge, when forming the aluminum oxygen compound layer 30 by electrolytic treatment, the present inventors are formed by dissolution of tin phosphate in the phosphate compound layer 20 in the electrolytic treatment solution. It is found that the phosphate ions that are hardly soluble in acid and alkali are precipitated as the aluminum oxygen compound layer 30 by the formed phosphate ions, and the corrosion resistance of the formed aluminum oxygen compound layer 30 can be improved. became. Thereby, the surface-treated steel sheet 1 to be obtained has sufficient corrosion resistance even when the coating layer 40 mainly composed of an organic material is not formed on the surface, and as a metal container for non-coating applications in which the coating layer 40 is not formed. Can also be suitably used. In addition, as an electrolytic treatment for forming the aluminum oxygen compound layer 30, when performing a cathodic electrolytic treatment (electrolytic treatment using the tin-plated steel sheet 10 on which the phosphoric acid compound layer 20 is formed as a cathode), as shown in FIG. In addition, in the vicinity of the surface of the tin-plated steel sheet 10 as the cathode, tin oxide and the like are reduced to produce tin ions Sn ²⁺ and hydroxide ions (OH ⁻ ) to be produced, which raises the pH. Here, the ionization equilibrium of the phosphate ion in the electrolytic treatment solution is inclined toward the higher the abundance ratio of the tertiary phosphate ion (PO ₄ ³⁻ ) as the pH of the electrolytic treatment solution is higher. The phosphate precipitated as the aluminum oxygen compound layer 30 by the tertiary phosphate ions (PO ₄ ³⁻ ) becomes particularly insoluble in acids and alkalis. Corrosion resistance is further improved.

In the surface-treated steel sheet 1 of the present embodiment, as described above, a part of the tin plating layer 12 of the tin-plated steel sheet 10 is dissolved to form the phosphate compound layer 20. Since the portion is dissolved to form the aluminum oxygen compound layer 30, the tin plating layer 12, the phosphate compound layer 20, and the aluminum oxygen compound layer 30 are configured to be mixed near each boundary. Yes. For example, in this embodiment, both the phosphate compound layer 20 and the aluminum oxygen compound layer 30 may contain tin phosphate and aluminum phosphate.

The immersion treatment liquid for forming the phosphate compound layer 20 includes phosphoric acid (H ₃ PO ₄ ), sodium dihydrogen phosphate (NaH ₂ PO) as compounds for generating phosphate ions in the immersion treatment liquid. ₄ ), disodium hydrogen phosphate (Na ₂ HPO ₄ ), phosphorous acid (H ₃ PO ₃ ) and the like can be used. These phosphoric acids and phosphates may be used alone or in combination, and among them, a mixture of phosphoric acid and sodium dihydrogen phosphate precipitates tin phosphate well as the phosphoric acid compound layer 20. This is preferable.

The concentration of phosphate ions in the immersion treatment solution is not particularly limited, but is preferably 5 to 200 g / L in terms of phosphorus amount. By setting the concentration of phosphate ions in the immersion treatment liquid within the above range, tin phosphate can be favorably deposited on the tin-plated steel sheet 10.

The pH of the immersion treatment liquid is preferably 1 to 4, more preferably 1.3 to 3.7. If the pH is less than 1, the formed tin phosphate may be dissolved. On the other hand, if the pH exceeds 4, the dissolution of the oxide film layer on the surface of the tin-plated steel sheet 10 tends to be insufficient, and the phosphate compound layer 20 is difficult to be formed in the portion where a large amount of the oxide film layer remains. There is a possibility that the homogeneous phosphoric acid compound layer 20 cannot be formed on the plated steel sheet 10. In addition, when the pH exceeds 4, the formed tin phosphate becomes difficult to dissolve in the electrolytic treatment liquid for forming the aluminum oxygen compound layer 30, and the aluminum oxygen compound layer 30 is appropriately made to contain a phosphate. It is not possible to obtain the effect of improving the corrosion resistance of the aluminum oxygen compound layer 30 described above.

The temperature of the immersion treatment liquid is preferably 35 to 55 ° C, more preferably 40 to 50 ° C. If the temperature is too low, the phosphoric acid compound layer 20 may be difficult to be formed. On the other hand, if the temperature is too high, the formed phosphoric acid compound layer 20 becomes non-uniform and mottles are generated, and although there is no problem in quality, the appearance quality may be deteriorated.

<Aluminum oxygen compound layer 30>
In the present embodiment, the tin-plated steel sheet 10 on which the phosphoric acid compound layer 20 is formed is washed with water as appropriate, and then subjected to electrolytic treatment in an electrolytic treatment liquid containing Al ions, so that aluminum is formed on the phosphoric acid compound layer 20. An oxygen compound is deposited to form the aluminum oxygen compound layer 30. The electrolytic treatment method may be either anodic electrolytic treatment or cathodic electrolytic treatment. However, from the viewpoint that the aluminum oxygen compound layer 30 can be satisfactorily formed, the cathodic electrolytic treatment is preferable.

The content of Al ions in the electrolytic treatment solution for forming the aluminum oxygen compound layer 30 can be appropriately selected according to the coating amount of the aluminum oxygen compound layer 30 to be formed. And preferably 0.5 to 10 g / l, more preferably 1 to 5 g / l. By setting the content of Al ions in the electrolytic treatment liquid within the above range, the stability of the electrolytic treatment liquid can be improved and the deposition efficiency of the aluminum oxygen compound can be improved.

In the present embodiment, nitrate ions may be added to the electrolytic treatment solution used for forming the aluminum oxygen compound layer 30. When nitrate ions are added to the electrolytic treatment liquid, the content of nitrate ions in the electrolytic treatment liquid is preferably 11,500 to 25,000 ppm by weight. By setting the content of nitrate ions in the above range, the conductivity of the electrolytic treatment liquid can be adjusted to an appropriate range.

Moreover, it is preferable that the electrolytic treatment liquid used for forming the aluminum oxygen compound layer 30 does not contain F ions. With respect to the electrolytic treatment liquid used for forming the aluminum oxygen compound layer 30, it is possible to form a dense aluminum oxygen compound layer 30 with a small particle size by not containing F ions. It can be excellent in resistance to sulfur blackening. When F ions are contained in the electrolytic treatment solution, SnF ₂ is formed, which is taken in by the aluminum oxygen compound layer 30, thereby reducing sulfur blackening resistance and corrosion resistance.

In addition, the said electrolytic treatment liquid should just contain F ion substantially, and may contain F ion as long as it is the amount of impurities. That is, since F atoms are slightly contained in industrial water or the like, F ions derived from such F atoms may be mixed in the electrolytic treatment solution. At this time, as F ions in the electrolytic treatment liquid, there are F ions forming complex ions with metals, free F ions, etc., and the total amount of these F ions is preferably If it is 50 ppm by weight or less, more preferably 20 ppm or less, and even more preferably 5 ppm or less, the amount of F ions contained in the electrolytic treatment liquid is about the amount of impurities, and the electrolytic treatment liquid substantially contains F ions. It can be judged that it is not.

In the present invention, examples of the method for measuring the contents of F ions and nitrate ions in the electrolytic treatment solution include a method of measuring by quantitative analysis by ion chromatography.

The electrolytic treatment solution for forming the aluminum oxygen compound layer 30 includes at least one of organic acids (citric acid, lactic acid, tartaric acid, glycolic acid, etc.), polyacrylic acid, polyitaconic acid, and phenol resin. The above additives may be added. In the present embodiment, an organic material can be contained in the formed aluminum oxygen compound layer 30 by appropriately adding these additives alone or in combination to the electrolytic treatment liquid. The adhesion of the coating layer 40 formed on the top can be improved.

In addition, with respect to the electrolytic treatment liquid for forming the aluminum oxygen compound layer 30, it is desirable to adjust the content of phosphate ions, and the content of phosphate ions in the electrolytic treatment liquid is the amount of phosphorus, preferably 0. 0.55 g / L or less, more preferably 0.33 g / L or less, and still more preferably 0.11 g / L.

That is, in this embodiment, when the aluminum oxygen compound layer 30 is formed by electrolytic treatment, tin phosphate and the like are dissolved from the phosphate compound layer 20 in the electrolytic treatment liquid used for forming the aluminum oxygen compound layer 30. Then, phosphate ions are generated. If the amount of generated phosphate ions is too large, the phosphate ions bind to Al ions and precipitate as aluminum phosphate in the electrolytic treatment liquid. As a result, in the electrolytic treatment liquid, the aluminum oxygen compound layer The amount of Al ions used for forming 30 decreases, and the formation efficiency of the aluminum oxygen compound layer 30 decreases. Further, the aluminum phosphate compound precipitated in the electrolytic treatment solution causes the formed aluminum oxygen compound layer 30 to become non-uniform and mottled, and there is no problem in quality, but the appearance quality tends to deteriorate. .

On the other hand, when the content of phosphate ions in the electrolytic treatment liquid for forming the aluminum oxygen compound layer 30 is in the above range, the formed aluminum oxygen compound layer 30 becomes uniform, and the surface treatment to be obtained The appearance quality of the steel plate 1 is improved.

When the aluminum oxygen compound layer 30 is formed by electrolytic treatment, it is preferable to use an intermittent electrolysis system in which a cycle of energization and deenergization is repeated. In this case, the total energization time (energization and deenergization of the base material) is used. The total energization time when the cycle is repeated a plurality of times is preferably 1.5 seconds or less, more preferably 1 second or less. The number of cycles of energization and deenergization is preferably 1 to 10 times, and may be adjusted along with the energization time so that the aluminum content in the aluminum oxygen compound layer 30 is appropriate. The appropriate content of aluminum in the aluminum oxygen compound layer 30 is preferably 3 to 40 mg / m ² , more preferably 5 to 20 mg / m ² , still more preferably 5 to 15 mg / m ² , and particularly preferably 5. 7 to 10.0 mg / m ² .

Further, when the aluminum oxygen compound layer 30 is formed, any counter electrode may be used as long as it does not dissolve in the electrolytic treatment solution while the electrolytic treatment is being performed. A titanium plate coated with iridium oxide or a titanium plate coated with platinum is preferred because it has a small overvoltage and is difficult to dissolve in an electrolytic treatment solution.

The aluminum oxygen compound layer 30 formed as described above is mainly composed of aluminum oxide or the like, but also includes aluminum hydroxide and phosphate. Examples of the phosphate include aluminum phosphate and an oxygen compound containing phosphoric acid (Al (PO ₄ ) _y O _{z and the} like). This phosphate is an aluminum oxygen compound as described below. Deposit as layer 30. That is, in the present embodiment, as described above, when the tin-plated steel sheet 10 on which the phosphate compound layer 20 is formed is subjected to an electrolytic treatment with an electrolytic treatment solution containing Al ions, the phosphate compound layer 20 is configured. A part of tin phosphate is dissolved, and phosphate ions such as aluminum phosphate and phosphate such as oxygen compound containing phosphoric acid are precipitated. Further, in the formation of the aluminum oxygen compound layer 30, tin ions Sn ²⁺ are generated in the electrolytic treatment solution by dissolution of the phosphate compound layer 20 or dissolution of exposed portions of the tin plating that is not coated with the phosphate compound. Therefore, a part of tin oxide (SnO _x ) is included in the aluminum oxygen compound layer 30 in addition to tin phosphate. According to this embodiment, when the aluminum oxygen compound layer 30 contains a phosphate, when the coating layer 40 is formed on the aluminum oxygen compound layer 30 by baking, the tin-plated steel sheet 10 is heated by the heat during baking. The growth of the oxide film layer can be suppressed, and as a result, the adhesion of the coating layer 40 formed on the surface of the surface-treated steel sheet 1 can be improved.

The reason why such an effect can be obtained by including a phosphate in the aluminum oxygen compound layer 30 is not necessarily clear, but is considered as follows. First, as described above, the phosphoric acid compound layer 20 obtained by the immersion treatment is easily dissolved in the electrolytic treatment solution used for forming the aluminum oxygen compound layer 30 in terms of the chemical bonding state and surface form of tin phosphate contained therein. It will be a thing. And, when forming the aluminum oxygen compound layer 30 by electrolytic treatment, in the electrolytic treatment liquid, by the phosphate ions, phosphite ions, etc. generated by dissolving the tin phosphate of the phosphate compound layer 20, Phosphate precipitates as the aluminum oxygen compound layer 30, and the action of this phosphate can suppress the growth of the oxide film layer of the tin-plated steel sheet 10 due to heat during baking. The adhesion of the coating layer 40 to be formed is improved. In addition, when only tin phosphate is formed on the tin-plated steel sheet 10, the tin phosphate coating changes in quality over time, and initially the increase in the oxide film in the painting and baking process can be suppressed, but gradually becomes weaker, It is considered that the adhesion with the coating layer 40 is lowered. In the present invention, it is considered that by providing the aluminum oxygen compound layer 30, the alteration of tin phosphate is suppressed and the adhesion with the coating layer 40 is improved.

The aluminum content in the aluminum oxygen compound layer 30 is preferably 3 to 20 mg / m ² , more preferably 5 to 20 mg / m ² , still more preferably 5 to 15 mg / m ² , and particularly preferably 5.7 to 10. 0 mg / m ² . When the aluminum content in the aluminum oxygen compound layer 30 is too small, the oxide film layer on the surface of the tin-plated steel sheet 10 increases when the coating layer 40 made of an organic material is formed by baking coating. The aluminum oxygen compound layer 30 and the covering layer 40 tend to be easily peeled from the layer. On the other hand, if the aluminum content in the aluminum oxygen compound layer 30 is too large, the aluminum oxygen compound layer 30 may become brittle and cause cohesive failure.

Further, as described above, the aluminum oxygen compound layer 30 contains phosphate, but the content ratio (P / P) of the phosphorus amount (mol / m ² ) to the aluminum amount (mol / m ² ) in the aluminum oxygen compound layer 30 (P / Al) is preferably 0.06 to 0.35, more preferably 0.06 to 0.20. When the content ratio (P / Al) is less than 0.06, an oxide film layer on the surface of the tin-plated steel sheet 10 grows by heat during baking when the coating layer 40 made of an organic material is formed by baking coating. As a result, the aluminum oxygen compound layer 30 and the covering layer 40 tend to be easily peeled off from the oxide film layer. On the other hand, when the content ratio (P / Al) is more than 0.35, the formed aluminum oxygen compound layer 30 becomes non-uniform and mottles are generated. There is a tendency.

As described above, the surface-treated steel sheet 1 of the present embodiment is obtained.

In the surface-treated steel sheet 1 of this embodiment, the total amount of phosphorus contained in each layer (tin plating layer 12, phosphate compound layer 20, and aluminum oxygen compound layer 30) formed on the steel sheet 11 is preferably 0.4. ~ 10mg / ^{m 2,} more preferably 0.4 ~ 2.3mg / ^{m 2.} If the total amount of phosphorus contained in each layer is too small, an oxide film layer of the tin-plated steel sheet 10 grows due to heat during baking when the coating layer 40 made of an organic material is formed by baking, thereby oxidizing. The aluminum oxygen compound layer 30 and the coating layer 40 tend to be easily peeled from the film layer. On the other hand, if the total amount of phosphorus contained in each layer is too large, the content ratio of tin phosphate in the phosphate compound layer 20 increases, and this tin phosphate acts as an insulator, so that the aluminum oxygen compound layer 30 is formed. In the electrolytic treatment, the aluminum oxygen compound is deposited non-uniformly, and the aluminum oxygen compound layer 30 is formed with mottle and there is no problem in quality, but the appearance quality tends to deteriorate.

In this embodiment, as a method for measuring the total amount of phosphorus contained in each layer formed on the steel plate 11, for example, a method of quantitatively analyzing the obtained surface-treated steel plate 1 using a fluorescent X-ray analyzer. Is mentioned.

<Metal container>
Although the surface-treated steel sheet 1 of this embodiment is not specifically limited, It can be used as members, such as a can container and a can lid. When the surface-treated steel sheet 1 is used as a member such as a can container or a can lid, the surface-treated steel sheet 1 is used as it is (used for non-coating applications in which the coating layer 40 is not formed on the surface). You may shape | mold as a can lid | cover, and after forming the coating layer 40 which consists of organic materials on the aluminum oxygen compound layer 30 of the surface-treated steel plate 1, you may shape | mold in a can container, a can lid | cover, etc. It does not specifically limit as an organic material which comprises the coating layer 40, What is necessary is just to select suitably according to the use (for example, uses, such as a can container filled with a specific content) of the surface-treated steel plate 1, but thermoplasticity Examples thereof include a resin and a thermosetting resin.

Thermoplastic resins include polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic ester copolymers, olefin resin films such as ionomers, and polyesters such as polyethylene terephthalate and polybutylene terephthalate. A film, an unstretched film such as a polyvinyl chloride film or a polyvinylidene chloride film or a biaxially stretched film, or a polyamide film such as nylon 6, nylon 6, 6, nylon 11, or nylon 12 can be used. Among these, non-oriented polyethylene terephthalate obtained by copolymerizing isophthalic acid is particularly preferable. Moreover, the organic material for comprising such a coating layer 40 may be used independently, and different organic materials may be blended and used.
As the thermosetting resin, epoxy-phenol resin, polyester resin, or the like can be used.

When the thermoplastic resin is coated as the coating layer 40, it may be a single-layer resin layer or a multilayer resin layer formed by coextrusion or the like. When a multilayer polyester resin layer is used, a polyester resin having a composition with excellent adhesion is selected for the base layer, that is, the surface-treated steel sheet 1 side, and content resistance, that is, extraction resistance and flavor component non-adsorption on the surface layer This is advantageous because a polyester resin having a composition excellent in properties can be selected.
Examples of multilayer polyester resin layers are shown as surface layer / lower layer, polyethylene terephthalate / polyethylene terephthalate / isophthalate, polyethylene terephthalate / polyethylene / cyclohexylene dimethylene / terephthalate, polyethylene terephthalate / isolated with low isophthalate content. Polyethylene terephthalate / isophthalate having a high phthalate / isophthalate content, polyethylene terephthalate / isophthalate / [blend of polyethylene terephthalate / isophthalate and polybutylene terephthalate / adipate] and the like are of course not limited thereto. The thickness ratio of the surface layer to the lower layer is preferably in the range of 5:95 to 95: 5.

The coating layer 40 has a resin compounding agent known per se, for example, an antiblocking agent such as amorphous silica, an inorganic filler, various antistatic agents, a lubricant, an antioxidant (for example, tocophenol), and an ultraviolet absorber. Etc. can be blended according to a known formulation.

The thickness of the coating layer 40 formed on the surface-treated steel sheet 1 obtained according to the present invention is desirably 3 to 50 μm, particularly 5 to 40 μm in general with a thermoplastic resin coating. The later thickness is preferably in the range of 1 to 50 μm, particularly 3 to 30 μm. When the thickness is less than the above range, the corrosion resistance becomes insufficient, and when the thickness exceeds the above range, a problem is likely to occur in terms of workability.

Formation of the coating layer 40 on the surface-treated steel sheet 1 obtained by the present invention can be performed by any means. For example, in the case of thermoplastic resin coating, extrusion coating, cast film thermal bonding, biaxially stretched film It can be performed by a thermal bonding method or the like.

The thermal adhesion of the polyester resin to the surface-treated steel sheet 1 is performed by the amount of heat that the molten resin layer has and the amount of heat that the surface-treated steel sheet 1 has. The heating temperature of the surface-treated steel sheet 1 is generally 90 ° C. to 290 ° C., particularly 100 ° C. to 230 ° C., while the laminating roll temperature is suitably 10 ° C. to 150 ° C.
The covering layer 40 formed on the surface-treated steel sheet 1 can also be formed by thermally bonding a polyester resin film previously formed by a T-die method or an inflation film-forming method to the surface-treated steel sheet 1. . As the film, an unstretched film formed by a cast molding method in which the extruded film is rapidly cooled can be used, and this film is biaxially stretched sequentially or simultaneously at the stretching temperature, and the stretched film is heat-set. It is also possible to use a biaxially stretched film produced by the above method.

The surface-treated steel sheet 1 of the present invention can be formed as a can container by forming a coating layer 40 on the surface to obtain an organic material-coated steel sheet and then processing this. Although it does not specifically limit as a can container, For example, the seamless can 5 (two piece can) shown to FIG. 3 (A) and the three-piece can 5a (welding can) shown to FIG. 3 (B) are mentioned. The body 51 and the upper lid 52 constituting the seamless can 5 and the body 51a, the upper lid 52a and the lower lid 53 constituting the three-piece can 5a are all formed by forming the coating layer 40 on the surface-treated steel sheet 1 of the present embodiment. An organic material-coated steel sheet is formed. 3A and 3B, the cross-sectional views of the seamless can 5 and the three-piece can 5a are obtained by rotating FIG. 1 described above by 90 ° so that the coating layer 40 is on the inner surface side of the can. . The cans 5 and 5a shown in FIGS. 3 (A) and 3 (B) are drawn, drawn / re-drawn, and bent and stretched by drawing / re-drawing (stretching) so that the coating layer 40 is on the inner surface side of the can. ), Can be produced by subjecting to conventionally known means such as bending / stretching / ironing by drawing / redrawing or drawing / ironing.
In the seamless can 5 subjected to advanced processing such as bending / stretching (stretching) by drawing / redrawing, bending / stretching / ironing by drawing / redrawing, the coating layer 40 is thermoplastic by an extrusion coating method. It is particularly preferable that it is made of a resin coating.
That is, since the organic material-coated steel sheet is excellent in work adhesion, it is possible to provide a seamless can having excellent corrosion resistance and excellent corrosion resistance even when subjected to severe processing.

As described above, the surface-treated steel sheet 1 of the present invention can be manufactured by forming a coating layer 40 on the surface to obtain an organic material-coated steel sheet, and then processing this to produce a can lid. The can lid is not particularly limited, and examples thereof include a flat lid, a stay-on-tab type easy open can lid, and a full open type easy open can lid.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
In addition, the evaluation method of each characteristic is as follows.

<Analysis of treatment liquid>
For the immersion treatment solution and the electrolytic treatment solution, using an ICP emission analyzer (ICPE-9000, manufactured by Shimadzu Corporation), the phosphate ion concentration or Al ion concentration was measured using an ion chromatograph (Dionex, DX-500). The F ion concentration and the nitrate ion concentration were measured. Further, the pH of the immersion treatment solution and the electrolytic treatment solution was measured using a pH meter (manufactured by Horiba Ltd.). Further, the conductivity of the immersion treatment solution and the electrolytic treatment solution was measured using a conductivity meter (manufactured by Nikko Hansen, CyberScan CON110).

<Appearance evaluation>
The appearance of the surface-treated steel sheet 1 was visually evaluated according to the following criteria.
A: The surface color of the surface-treated steel sheet 1 was uniform.
X: Spots were generated on the surface of the surface-treated steel sheet 1.

<Measurement of phosphorus content and aluminum content>
About the surface-treated steel plate 1, the amount of phosphorus and the amount of aluminum contained in each layer formed on the steel plate 11 were measured in units of mg / m ² using a fluorescent X-ray analyzer (manufactured by Rigaku Corporation, ZSX100e). Further, the obtained measurement values, in terms of units of mol / ^{m 2,} was calculated content ratio of phosphorus content to aluminum content ^{(mol / m 2) (mol} / m 2) to (P / Al). In addition, the measurement of the amount of phosphorus and the amount of aluminum and the calculation of P / Al were performed for all examples and comparative examples described later.

<Evaluation of paint adhesion>
The organic material-coated steel plate formed by forming the coating layer 40 on the surface-treated steel plate 1 is subjected to a retort treatment at a temperature of 125 ° C. for 30 minutes, and then a grid having a depth reaching the steel plate 11 at intervals of 5 mm is inserted and taped. It peeled, the degree of peeling was observed visually, and the following references | standards evaluated. In addition, paint adhesion evaluation was performed about all the Examples and comparative examples which are mentioned later.
3 points: As a result of visual judgment, peeling of the paint was not recognized.
2 points: As a result of visual judgment, peeling of the paint was recognized at an area ratio of 1/5 or less.
1 point: As a result of visual determination, peeling of the paint was recognized at an area ratio exceeding 1/5.
In the paint adhesion evaluation, when the evaluation was 2 points or more according to the above criteria, it was determined that the surface-treated steel sheet 1 had sufficient paint adhesion when used as a food can application.

<Evaluation of growth of oxide layer>
The surface-treated steel sheet 1 was heat-treated at a temperature of 205 ° C. for 30 minutes, and the amount of tin oxide film layer formed on the surface of the tin-plated steel sheet 10 before and after the heat treatment was measured. The amount of the oxide film layer was evaluated by the amount of electricity required to remove the oxide film layer by electrochemical reduction. A 1 / 1000N hydrogen bromide solution was used as the electrolytic solution, and electrolysis was performed under a current density of 25 μA / cm ² . Evaluation of the growth of the oxide film layer is to calculate the value obtained by dividing the amount of the oxide film layer after the heat treatment by the amount of the oxide film layer before the heat treatment (the oxide film layer after the heat treatment / the oxide film layer before the heat treatment). It was evaluated that the larger the value, the easier the oxide film layer grows by heat treatment. The evaluation of the growth of the oxide film layer was performed for all examples and comparative examples described later.
○: The oxide film layer after heat treatment / the oxide film layer before heat treatment was 1.2 or less.
(Triangle | delta): The oxide film layer after heat processing / the oxide film layer before heat processing exceeded 1.2 and was 1.4 or less.
X: The oxide film layer after the heat treatment / the oxide film layer before the heat treatment exceeded 1.4.

<Sulfurization blackening resistance evaluation (model solution)>
The organic material-coated steel sheet formed by forming the coating layer 40 on the surface-treated steel sheet 1 was cut into 40 mm square, and then the cut surface was protected with a 3 mm width tape to prepare a test piece. Next, the prepared test piece was put into an empty can (Toyo Seikan Co., Ltd., J280TULC), and the following model solution was filled in the test piece so that all the test pieces were immersed therein. A 5 hour retort treatment was performed.
Model solution: 6 g of sodium dihydrogen phosphate _{(NaH 2 PO 4) 3.0g /} L, 7.1g of disodium hydrogen phosphate _{(Na 2 HPO 4) / L} , L- cysteine hydrochloride monohydrate An aqueous solution of pH 7.0 containing at a concentration of / L was then opened, and the degree of blackening of the test piece was visually observed and evaluated according to the following criteria. In addition, the sulfide blackening resistance evaluation (model solution) was performed for all examples and comparative examples described later.
3 points: As a result of visual determination, the degree of blackening was clearly less than that of Comparative Example 3.
2 points: As a result of visual determination, the degree of blackening was the same as in Comparative Example 3.
1 point: As a result of visual determination, the degree of blackening was clearly deeper than that of Comparative Example 3.
In addition, in the anti-sulfur blackening evaluation (model solution), when the evaluation is 2 points or more according to the above criteria, the surface-treated steel sheet 1 has sufficient anti-sulfur blackening when used as a food can application. It was judged that.

Example 1
First, a low carbon cold-rolled steel plate (plate thickness: 0.225 mm) was prepared as the steel plate 11.

Next, the prepared steel sheet was degreased by performing cathodic electrolytic treatment at 60 ° C. for 10 seconds using an aqueous solution of an alkaline degreasing agent (Nippon Quaker Chemical Co., Ltd., Formula 618-TK2). Next, the degreased steel sheet was washed with tap water and then pickled by dipping it in a pickling agent (5% by volume aqueous solution of sulfuric acid) at room temperature for 5 seconds. Thereafter, it was washed with tap water, and a steel plate was subjected to tin plating under the following conditions using a known ferrostan bath, and a tin plating layer 12 having a tin amount of 2.8 g / m ² was formed on the surface of the steel plate. . Thereafter, the steel plate on which the tin plating layer 12 is formed is washed with water, heated by flowing a direct current, heated to a temperature higher than the melting point of tin, and then subjected to a reflow treatment in which tap water is rapidly cooled to obtain a tin-plated steel plate 10. Produced.
Bath temperature: 40 ° C
Current density: 10 A / dm ²
Anode material: Commercially available 99.999% metallic tin Total energization time: 5 seconds (5 cycles when energization time is 1 second and stop time 0.5 seconds is one cycle)

And the phosphoric acid compound layer 20 was formed on the tin plating steel plate 10 by immersing the obtained tin plating steel plate 10 in the immersion treatment liquid on the following conditions.
Immersion treatment solution: pH 1.3 aqueous solution in which phosphorous acid is dissolved at a concentration of 10 g / L (treatment solution A in Table 1)
Immersion treatment solution temperature: 40 ° C
Immersion time: 3 seconds

In addition, about the immersion process liquid used for formation of the phosphoric acid compound layer 20, according to the method mentioned above, the process liquid was analyzed. The results are shown in Table 1. In Table 1, the concentration (g / L) of phosphorus atoms calculated according to the concentration of the dissolved phosphate compound is also shown. For Example 1, an immersion treatment liquid shown as treatment liquid A in Table 1 was used to form the phosphoric acid compound layer 20. Similarly, the processing liquid B was used for Examples 2 and 3 to be described later, the processing liquid C was used for Examples 4 and 6 to be described later, and the processing liquid D was used for Example 5 to be described later. Table 2 shows conditions of the immersion treatment liquid and the immersion time when the phosphate compound layer 20 was formed on the tin-plated steel sheet 10.

Next, the tin-plated steel sheet 10 on which the phosphoric acid compound layer 20 was formed was washed with water, and then immersed in the electrolytic treatment solution under the following conditions, and the electrolytic treatment solution was stirred and disposed at a distance of 17 mm between the electrodes. The aluminum oxygen compound layer 30 was formed by performing cathodic electrolysis using the iridium oxide-coated titanium plate as an anode. Immediately after that, the surface-treated steel sheet 1 in which the phosphoric acid compound layer 20 and the aluminum oxygen compound layer 30 were formed in this order on the tin-plated steel sheet 10 was obtained by washing with running water and drying. In addition, about the electrolytic processing liquid used for formation of the aluminum oxygen compound layer 30, the processing liquid was analyzed according to the method mentioned above. The results are shown in Table 1. In all examples and comparative examples described later, an electrolytic treatment solution shown as treatment solution F in Table 1 was used for forming the aluminum oxygen compound layer 30. Table 2 shows the conditions of the electrolytic treatment when forming the aluminum oxygen compound layer 30.
Electrolytic treatment solution: Aluminum nitrate is dissolved as an Al compound to have an Al ion concentration of 1500 ppm by weight, an nitrate ion concentration of 15,000 ppm by weight, and an F ion concentration of 0 ppm by weight (pH 3.0). Treatment liquid F)
Electrolytic solution temperature: 40 ° C
Current density: 4 A / dm ²
Total energization time: 0.3 seconds (energization time 0.3 seconds, number of cycles once)

And about the obtained assertion processing steel plate 1, the amount of phosphorus and the amount of aluminum were measured according to the method mentioned above. The results are shown in Table 3.

Next, the surface-treated steel sheet 1 was subjected to a heat treatment at a temperature of 190 ° C. for 10 minutes, and then an epoxy phenol-based paint was applied so that the coating thickness after baking and drying was 70 mg / dm ^2. By performing baking for a minute, the organic material covering steel plate which formed the coating layer 40 on the surface treatment steel plate 1 was obtained. Next, the obtained organic material-coated steel sheet was subjected to paint adhesion evaluation, anti-sulfur blackening evaluation (model solution), evaluation of oxide film layer growth, and appearance evaluation according to the above-described methods. The results are shown in Table 3.

Example 2
When forming the phosphoric acid compound layer 20 on the tin-plated steel sheet 10, an aqueous solution of pH 1.8 in which phosphoric acid is dissolved at a concentration of 30 g / L and sodium dihydrogen phosphate is dissolved at a concentration of 30 g / L as an immersion treatment solution. A surface-treated steel sheet 1 and an organic material-coated steel sheet were produced in the same manner as in Example 1 except that (treatment liquid B in Table 1) was used, and evaluation was performed in the same manner. The results are shown in Table 3.

Example 3
When forming the aluminum oxygen compound layer 30 on the phosphate compound layer 20, the surface-treated steel sheet 1 and the organic material-coated steel sheet were prepared in the same manner as in Example 2 except that the total energization time was 0.5 seconds. The same evaluation was performed. The results are shown in Table 3.

Example 4
When forming the phosphoric acid compound layer 20 on the tin-plated steel sheet 10, an aqueous solution of pH 2.4 in which phosphoric acid is dissolved at a concentration of 10 g / L and sodium dihydrogen phosphate is dissolved at a concentration of 30 g / L as an immersion treatment solution. A surface-treated steel sheet 1 and an organic material-coated steel sheet were prepared in the same manner as in Example 1 except that (Processing liquid C in Table 1) was used, and evaluated in the same manner. The results are shown in Table 3.

Example 5
When forming the phosphoric acid compound layer 20 on the tin-plated steel sheet 10, phosphoric acid is used as an immersion treatment solution at a concentration of 10 g / L, sodium dihydrogen phosphate at a concentration of 30 g / L, and trisodium phosphate at a concentration of 7 g / L. A surface-treated steel sheet 1 and an organic material-coated steel sheet were prepared in the same manner as in Example 1 except that an aqueous solution of pH 3.7 dissolved in L (treatment liquid D in Table 1) was used and the immersion time was 4 seconds. The same evaluation was made. The results are shown in Table 3.

Example 6
Before forming the phosphate compound layer 20 on the tin-plated steel sheet 10, the tin-plated steel sheet 10 was immersed in an aqueous solution containing hydrochloric acid. Thereafter, the immersion time in forming the phosphoric acid compound layer 20 on the tin-plated steel sheet 10 is 2 seconds, the number of cycles in forming the aluminum oxygen compound layer 30 on the phosphoric acid compound layer 20 is 2, and the total energization time The surface-treated steel sheet 1 and the organic material-coated steel sheet were produced in the same manner as in Example 4 except that the time was set to 0.6 seconds, and evaluation was performed in the same manner. The results are shown in Table 3.

<< Comparative Example 1 >>
When forming the phosphoric acid compound layer 20 on the tin-plated steel sheet 10, an aqueous solution having a pH of 6.4 in which phosphoric acid is dissolved at a concentration of 10 g / L and sodium dihydrogen phosphate is dissolved at a concentration of 30 g / L as an immersion treatment solution. A surface-treated steel sheet 1 and an organic material-coated steel sheet were prepared and evaluated in the same manner as in Example 1 except that (treatment liquid E in Table 1) was used and the immersion time was 5 seconds. The results are shown in Table 3.

<< Comparative Example 2 >>
When forming the phosphoric acid compound layer 20 on the tin-plated steel sheet 10, the surface-treated steel sheet 1 and the organic material-coated steel sheet were produced in the same manner as in Example 4 except that the temperature of the immersion treatment liquid was 30 ° C. Evaluation was performed in the same manner. The results are shown in Table 3.

<< Comparative Example 3 >>
By forming the aluminum oxygen compound layer 30 and the coating layer 40 in this order directly on the tin-plated steel plate 10 in the same manner as in Example 1 without forming the phosphate compound layer 20, the surface-treated steel plate and organic A material-coated steel sheet was obtained. The obtained surface-treated steel sheet and organic material-coated steel sheet were evaluated in the same manner as in Example 1. The results are shown in Table 3.

《Discussion》
As shown in Table 3, a phosphoric acid compound layer 20 having a phosphorus amount of 0.4 to 10 mg / m ² is formed by immersing the tin-plated steel sheet 10, and on the phosphoric acid compound layer 20. In Examples 1 to 6 in which the aluminum oxygen compound layer 30 was formed, the results of the paint adhesion evaluation, the sulfide blackening resistance evaluation (model solution), the oxide film layer growth evaluation, and the appearance evaluation were all good. In addition to being excellent in quality, it was confirmed that the coating layer 40 was excellent in adhesion, corrosion resistance and sulfur blackening resistance, and suitable for applications such as metal containers used over a long period of time.

On the other hand, as shown in Table 3, Comparative Examples 1 and 2 in which the amount of phosphorus in the phosphoric acid compound layer and the aluminum oxygen compound layer is 0.2 mg / m ² or less are used for paint adhesion evaluation and sulfur blackening resistance evaluation. It was confirmed that the results were all bad, the adhesiveness of the coating layer 40 was poor, and the suitability of the actual contents was poor. Moreover, the comparative example 3 which formed the aluminum oxygen compound layer 30 directly on the tin-plated steel plate 10 without forming the phosphoric acid compound layer 20 by immersion treatment is paint adhesion evaluation and evaluation of the growth of an oxide film layer. These results were all bad, and it was confirmed that the adhesion of the coating layer 40 was poor.

DESCRIPTION OF SYMBOLS 1 ... Surface treatment steel plate 10 ... Tin plating steel plate 11 ... Steel plate 12 ... Tin plating layer 20 ... Phosphate compound layer 30 ... Aluminum oxygen compound layer 40 ... Covering layer

Claims (7)

A tin-plated steel sheet obtained by performing tin plating on a steel sheet is subjected to an immersion treatment in which an immersion treatment solution containing phosphate ions is immersed without performing an electrolytic treatment. A phosphate compound layer forming step of forming a phosphate compound layer of 4 to 10 mg / m ² ;
An aluminum oxygen compound layer forming step of forming an aluminum oxygen compound layer on the phosphoric acid compound layer by electrolytic treatment using an electrolytic treatment solution containing aluminum. The method for producing a surface-treated steel sheet according to claim 1, wherein in the phosphoric acid compound layer forming step, a treatment liquid having a pH of 1.0 to 4.0 is used as the immersion treatment liquid. The method for producing a surface-treated steel sheet according to claim 1 or 2, wherein a temperature of the immersion treatment liquid when dipping the tin-plated steel sheet is 35 to 55 ° C in the phosphate compound layer forming step. The total amount of aluminum contained in the respective layers formed on the tin-plated steel sheet, 3 to a method for producing a surface-treated steel sheet according to any one of claims 1 to 3, 40 mg / m ^2. The surface according to any one of claims 1 to 4, wherein in the aluminum oxygen compound layer forming step, a treatment solution having a phosphoric acid content of 0.55 g / L or less is used as the electrolytic treatment solution. A method for producing a treated steel sheet. The method for producing a surface-treated steel sheet according to any one of claims 1 to 5, wherein in the aluminum oxygen compound layer forming step, a treatment solution substantially free of F ions is used as the electrolytic treatment solution. As the tin-plated steel sheet,
A tin-plated steel sheet comprising the steel sheet, a tin alloy layer formed on the steel sheet, and a tin-plated layer formed on the tin alloy layer and having a tin content of 0.5 g / m ² or more is used. The method for producing a surface-treated steel sheet according to any one of 1 to 6.

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