TW202124788A - Sn-based plated steel sheet wherein the depth position A where the Mn element concentration is the largest is located on the surface side of the film layer relative to the depth position B where the Zr element concentration is the largest - Google Patents

Abstract

The present invention can provide a Sn-based plated steel sheet having excellent yellowing resistance, coating film adhesion, and sulfide black resistance without performing conventional chromate treatment. The Sn-based plated steel sheet of the present invention includes: a steel plate on the Sn-based plating layer on at least one side of the steel plate; and a film layer on the Sn-based plating layer. The Sn-based plating layer contains 0.10 to 15.00g/m2 Sn per unit area in terms of equivalent of metal Sn. The film layer contains Zr oxide and Mn oxide. The content of Zr oxide is 0.20 to 50.00mg/m2 per unit area in terms of equivalent of metal Zr. Relative to the content of the equivalent of the metal Zr of the Zr oxide, the content of the equivalent of the metal Mn of the Mn oxide is 0.01 to 0.50 times on a mass basis. In the depth-direction element analysis using XPS, the depth position A where the Mn element concentration is the largest is located on the surface side of the film layer relative to the depth position B where the Zr element concentration is the largest, and the depth-direction distance between the depth position A and the depth position B is 2nm or more.

Description

Sn series plated steel sheet

The present invention relates to a Sn-based plated steel sheet.

Tin (Sn)-based plated steel sheets are commonly referred to as "tinplate" and are widely used for beverage cans or food cans. This is because Sn is safe to the human body and is a beautiful-looking metal. This Sn-based plated steel sheet is mainly manufactured by an electroplating method. This is because the electroplating method is more advantageous than the hot-dip plating method in order to minimize the use amount of the higher-priced metal Sn. Sn-based plated steel sheets are usually treated with chromate (electrolytic treatment, immersion treatment, etc.) using a hexavalent chromate solution after plating or after the heating and melting treatment after plating is used to impart a beautiful metallic luster. ), apply a chromate film on the Sn-based plating layer. The effect of the chromate film is to prevent the yellowing of the appearance by suppressing the oxidation of the surface of the Sn-based plating layer, and to prevent the deterioration and improvement of the adhesion of the coating film due to the cohesive destruction of tin oxide in the use after coating. Resistance to sulfide blackening, etc.

On the other hand, in recent years, due to the increasing awareness of environmental and safety concerns, not only the final product is required to be free of hexavalent chromium, but also chromate treatment is not required. However, as mentioned above, Sn-based plated steel sheets with no chromate film will cause yellowing of the appearance, decreased adhesion of the coating film, or decreased resistance to sulfide blackening due to the growth of tin oxide.

Therefore, several proposals have been made for Sn-based plated steel sheets that have been treated with a coating instead of the chromate coating.

For example, the following Patent Document 1 proposes a tin-based plated steel sheet in which a chemical conversion coating containing P and Si is formed by a treatment using a chemical conversion treatment solution containing a phosphoric acid ion and a silane coupling agent.

The following Patent Document 2 proposes a tin-plated steel sheet with a chemical conversion treatment film and a reactant layer with a silane coupling agent. The chemical conversion treatment film contains Al, P, and selected from Ni, Co, and Cu. At least one.

The following Patent Document 3 proposes a method of manufacturing a Sn-plated steel sheet in which after heavy-layer plating of Zn on Sn plating, it is heated until the Zn single-plated layer substantially disappears.

The following patent document 4 individually proposes a steel sheet for a container with a Zr coating on a surface treatment layer containing Sn; the following patent document 5 proposes a steel sheet for a container with a Zr compound coating layer.

The following Patent Document 6 proposes a steel sheet for a container having a base Ni layer, an island-shaped Sn plating layer, a chemical conversion treatment layer containing tin oxide and tin phosphate, and a Zr-containing coating layer.

The following Patent Document 7 proposes a steel sheet for a container having a tin-containing oxide and a coating film of Zr, Ti, and P on the surface of a tin plating layer. Patent Document 7 also proposes that alternate electrolysis in which cathode electrolysis treatment and anodic electrolysis treatment are alternately performed when forming a film is also proposed. Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2004-060052 Patent Document 2: Japanese Patent Laid-Open No. 2011-174172 Patent Document 3: Japanese Patent Laid-Open No. 63-290292 Patent Document 4: Japanese Patent Laid-Open No. 2007-284789 Patent Document 5: Japanese Patent Laid-Open No. 2010-013728 Patent Document 6: Japanese Patent Laid-Open No. 2009-249691 Patent Document 7: International Publication No. 2015/001598 Non-patent literature

Non-Patent Document 1: Japanese Society of Surface Science, "Surface Analytical Chemistry Book X-ray Photoelectron Spectroscopy", Maruzen Publishing Co., Ltd., July 1998, P.83.

Summary of the invention The problem to be solved by the invention

However, the Sn-based plated steel sheets proposed in Patent Literature 1 to Patent Literature 7 and the manufacturing method thereof cannot sufficiently suppress the growth of tin oxide over time. There is still room for improvement in degeneration.

Therefore, the present invention has been completed in view of the aforementioned problems. The object of the present invention is to provide a Sn-based plating with excellent yellowing resistance, coating film adhesion, and sulfide blackening resistance without the need for conventional chromate treatment. Steel plate. Means to solve the problem

In order to solve the aforementioned problems, the inventors of the present invention have worked hard as a result of research and found that by forming a film layer containing zirconium oxide and manganese oxide on the surface of a Sn-based plated steel sheet, it is possible to achieve yellowing resistance and coating without chromate treatment. Sn-based plated steel sheet with excellent film adhesion and resistance to sulfide black change. The gist of the present invention completed based on the foregoing observational knowledge is as follows.

(1) A Sn-based plated steel sheet comprising: a steel sheet; a Sn-based plating layer on at least one surface of the aforementioned steel sheet; and a film layer on the aforementioned Sn-based plating layer; the aforementioned Sn-based plating layer is made of metal Sn In conversion, each single side contains 0.10 g/m ² or more and 15.00 g/m ² or less of Sn; the coating layer contains zirconium oxide and manganese oxide; the content of the zirconium oxide in the coating layer is converted to metal Zr 0.20 mg/m ² or more and 50.00 mg/m ² or less per single side; relative to the content of the metal Zr of the zirconium oxide, the content of the metal Mn of the manganese oxide in the film layer is 0.01 on a mass basis Times or more and 0.50 times or less; in the depth-direction elemental analysis by X-ray photoelectron spectroscopy, the depth position A where the concentration of Mn element existing as the aforementioned manganese oxide is the largest is higher than the position A where the concentration of Zr element existing as the aforementioned zirconium oxide is the largest The depth position B is located on the surface side of the film layer, and the depth direction distance between the depth position A and the depth position B is 2 nm or more. (2) The Sn-based plated steel sheet according to (1), wherein on the surface of the coating layer, the mass of the zirconium oxide in the elemental analysis in the depth direction by X-ray photoelectron spectroscopy is the quality of the aforementioned zirconium oxide by X-ray photoelectron spectroscopy. 0.01 times or less the mass of the aforementioned manganese oxide in the elemental analysis in the depth direction. (3) The Sn-based plated steel sheet according to (1) or (2), wherein the depth direction distance between the aforementioned depth position A and the aforementioned depth position B is 4 nm or more. (4) The Sn-based plated steel sheet according to any one of (1) to (3), wherein the content of the zirconium oxide in the coating layer is 1.00 mg/m ² or more per side in terms of metal Zr and 30.00mg/m ² or less. (5) The Sn-based plated steel sheet according to any one of (1) to (4), wherein the content of the zirconium oxide in the coating layer is 2.00 mg/m ² or more per single side in terms of metal Zr. 10.00mg/m ² or less. (6) The Sn-based plated steel sheet according to any one of (1) to (5), wherein the content of the metal Zr of the aforementioned zirconium oxide is converted to the content of the metal Mn of the aforementioned manganese oxide in the coating layer It is 0.05 times or more and 0.40 times or less on a mass basis. (7) The Sn-based plated steel sheet according to any one of (1) to (6), wherein the content of the metal Zr of the aforementioned zirconium oxide is converted to the content of the metal Mn of the aforementioned manganese oxide in the coating layer It is 0.10 times or more and 0.20 times or less on a mass basis. Invention effect

As explained above, according to the present invention, it is possible to provide a Sn-based plated steel sheet having excellent yellowing resistance, coating film adhesion, and sulfide blackening resistance without performing conventional chromate treatment.

The form used to implement the invention

Hereinafter, preferred embodiments of the present invention will be described in detail. Furthermore, in this specification, the term "step" not only refers to an independent step, but in the case that it cannot be clearly distinguished from other steps, as long as the intended purpose of the step can be achieved, it is included in this term. In this specification, the term "steel plate" means a base material steel plate (ie, a plated substrate) that is a target for forming the Sn-based plating layer and the coating layer.

In addition, the present invention described below relates to a Sn-based plated steel sheet widely used in can applications such as beverage cans and food cans. More specifically, it relates to the provision of a Sn-based plated steel sheet with more excellent yellowing resistance, coating film adhesion, and sulfide blackening resistance without the need for conventional chromate treatment.

>1.Sn series plated steel sheet> First, the Sn-based plated steel sheet of this embodiment will be described with reference to FIG. 1. Fig. 1 is an explanatory diagram schematically showing an example of the structure of the Sn-based plated steel sheet of the present embodiment.

As shown schematically in FIG. 1, the Sn-based plated steel sheet 1 of the present embodiment has a steel plate (base material steel plate) 10, an Sn-based plating layer 20 on at least one surface of the steel plate 10, and a Sn-based plating layer 20 on的膜层30。 The film layer 30. The Sn-based plating layer 20 contains 0.10 g/m ² or more and 15.00 g/m ² or less of Sn per single side in terms of metal Sn; the coating layer 30 contains zirconium oxide and manganese oxide; the coating layer 30 contains zirconium oxide The content of metal Zr is calculated as 0.20 mg/m ² or more and 50.00 mg/m ² or less per single side; relative to the content of metal Zr of zirconium oxide, the content of metal Mn of manganese oxide in the coating layer 30 It is 0.01 times or more and 0.50 times or less on a mass basis; in depth-direction elemental analysis by X-ray photoelectron spectroscopy, the depth position A where the concentration of Mn is the largest as a manganese oxide is higher than Zr as a zirconium oxide The depth position B where the element concentration is the largest is located on the surface side of the coating layer, and the depth direction distance between the depth position A and the depth position B is 2 nm or more.

(1.1 steel plate) The steel plate 10 used as the base material of the Sn-based plated steel sheet 1 of the present embodiment is not particularly limited, and any steel plate can be used as long as it is a steel plate used for the Sn-based plated steel sheet for general containers. Such a steel plate 10 may be low-carbon steel or very low-carbon steel as an example.

(1.2 Sn-based plating layer 20) Sn-based plating is performed on at least one side of the steel sheet 10 as described above, and a Sn-based plating layer 20 is formed. With such a Sn-based plating layer 20, the corrosion resistance of the steel sheet 10 is improved. Furthermore, the "Sn-based plating layer" in this specification refers not only to plating using metallic Sn, but also includes at least one of alloys containing metallic Sn and metallic Fe, metallic Ni, or trace elements and impurities other than metallic Sn Sn-based plating layer.

In the Sn-based plating layer 20 of the present embodiment, the amount of metal Sn per Sn content per one side (that is, the amount of metal Sn conversion) is 0.10 g/m ² or more and 15.00 g/m ² or less. When the content of the Sn-based plating layer 20 per single side is less than 0.10 g/m ² in terms of the amount of metallic Sn, the corrosion resistance is poor and poor. The content of Sn per single side is ^{preferably 1.0 g/m 2} or more based on the amount of metal Sn. On the other hand, when the content of the Sn-based plating layer 20 per single side exceeds 15.00 g/m ² in terms of the amount of metal Sn, the corrosion resistance improvement effect achieved by the metal Sn is sufficient, and if it increases further, it is not good from an economic point of view. . In addition, there is also a tendency for the adhesion of the coating film to decrease. The content of Sn per single side is ^{preferably 13.00g/m 2} or less based on the amount of metal Sn.

Here, the amount of metal Sn of the Sn-based plating layer (that is, the Sn content per side of the Sn-based plating layer) is, for example, a value measured by the electrolytic method described in JIS G 3303 or the fluorescent X-ray method. Or, for example, the following method can also obtain the amount of metallic Sn in the Sn-based plating layer. Prepare a test piece with no film layer formed. After the test piece was immersed in 10% nitric acid, the Sn-based plating layer was dissolved and analyzed by ICP emission analysis (High Frequency Inductively Coupled Plasma Optical Emission Spectroscopy) using, for example, 799ce manufactured by Agilent Technologies (Ar ) As a device, determine the Sn in the obtained solution. In addition, the amount of metallic Sn can be obtained based on the intensity signal obtained by the analysis, the calibration curve made from the solution of known concentration, and the formation area of the Sn-based plating layer of the test piece. Alternatively, in the case of a test piece with a coating layer formed, the amount of metal Sn can be obtained by the calibration curve method using GDS (glow discharge light emission spectroscopy), for example, the method is as follows. Using a plated sample (reference sample) with a known amount of metal Sn, the relationship between the metal Sn in the reference sample and the intensity signal and sputtering rate was calculated in advance by GDS to create a calibration curve. Based on the calibration curve, the amount of metal Sn can be obtained from the intensity signal of the test piece with unknown amount of metal Sn and the sputtering speed. Here, when analyzing the Sn-based plated steel sheet from the surface to the depth direction, the depth from the Zr intensity signal to the depth of 1/2 of the maximum value of the Zr intensity signal to the Fe intensity signal is 1/ of the maximum value of the Fe intensity signal The depth of 2 is defined as the Sn-based plating layer. From the viewpoint of measurement accuracy and rapidity, it is better to use the fluorescent X-ray method in the industry.

(1.3 Coating layer 30) As described above, the coating layer 30 containing zirconium oxide and manganese oxide is formed on the Sn-based plating layer 20. The Sn-based plated steel sheet 1 of the present embodiment has a coating layer 30 on the surface of the Sn-based coating layer 20. The coating layer 30 coexists with the aforementioned zirconium oxide and manganese oxide in relation to the amount described later, which can further improve the yellowing resistance. , Coating film adhesion and resistance to sulfide blackening. Furthermore, the coating layer of only zirconium oxide or manganese oxide cannot sufficiently improve the yellowing resistance, coating film adhesion, and sulfide blackening resistance. The reason has not yet been determined, but the following findings have been found through detailed investigations by the inventors.

There is tin oxide on the surface of the conventional Sn-based plating layer, and the amount of tin oxide will increase over time, which will reduce the yellowing resistance or the adhesion of the coating film, and the resistance to sulfide blackening will also decrease.

In the case of a film that does not contain manganese oxide but contains zirconium oxide on the surface of the Sn-based plating layer, the barrier properties of the zirconium oxide layer itself tend to suppress the rate of increase of tin oxide over time. However, in the manufacturing process, since tin oxide contains a heterogeneous film in the zirconium oxide coating layer, oxygen and sulfur reach the Sn-based plating surface through the fine cracks existing in the fragile tin oxide, causing tin oxidation. Substances and tin sulfide gradually increase.

On the other hand, the surface of the Sn-based plating layer may contain a film containing no zirconium oxide but manganese oxide, and the adhesion of the manganese oxide to the Sn-based plating is insufficient, so the adhesion of the coating film is reduced.

However, if there is a coating layer 30 containing both zirconium oxide and manganese oxide on the surface of the Sn-based plating layer 20, the tin oxide contained in the coating layer 30 is reduced by manganese oxide to reduce the tin oxide . In addition, manganese oxide becomes an oxide with a higher oxidation number, thereby forming a film with high barrier properties, inhibiting the permeation of oxygen and sulfur, and reducing the generation of tin oxide and tin sulfide. As a result, the yellowing resistance or the adhesion of the coating film is improved, and the sulfide blackening resistance is also improved.

In order to achieve the above effect, zirconium oxide ^{of 0.20 mg/m 2} or more and 50.00 mg/m ² or less per metal Zr amount per one side is required in the coating layer 30. When the content of zirconium oxide is less than 0.20 mg/m ² in terms of the amount of metal Zr, the barrier properties of zirconium oxide are insufficient, and yellowing resistance, coating adhesion, and sulfide blackening resistance are not improved. The content of zirconium oxide per single side is ^{preferably 1.00 mg/m 2} or more in terms of the amount of metal Zr, and more preferably 2.00 mg/m ² or more. On the other hand, when the content of the zirconium oxide per one side exceeds 50.00 mg/m ² in terms of the amount of metal Zr, the zirconium oxide is excessive and the adhesion of the coating film is deteriorated. Per one surface of the zirconium oxide content in terms of Zr in an amount of 30.00mg / m ² or less is preferable, and 10.00mg / m ² or less preferred.

In order to achieve the above effects, the following conditions must be satisfied. The content of the manganese oxide in the coating layer 30 in terms of metal Mn relative to the content of the metal Zr of the zirconium oxide is 0.01 times or more and 0.50 times or less on a mass basis. When the amount of manganese oxide per one side is less than 1/100 in terms of the amount of metal Mn relative to the content of zirconium oxide in terms of metal Zr, the reduction of tin oxide contained in the film and the improvement of manganese oxide The oxidation is insufficient, and the yellowing resistance, coating film adhesion, and sulfide blackening resistance cannot be sufficiently improved. The content of the metal Mn of the manganese oxide in the coating layer 30 is preferably 0.05 times or more on a mass basis with respect to the content of the metal Zr of the zirconium oxide, and more preferably 0.10 times or more. On the other hand, when the amount of manganese oxide per one side exceeds 1/2 in terms of the amount of metal Mn relative to the content of zirconium oxide in terms of metal Zr, the excessive manganese oxide becomes easy to embrittlement, resulting in The adhesion of the coating film is poor. The content of the metal Mn of the manganese oxide in the coating layer 30 is preferably 0.40 times or less, and more preferably 0.20 times or less on a mass basis with respect to the content of the metal Zr of the zirconium oxide.

In addition, in the coating layer 30, manganese oxide needs to be concentrated on the surface side of the coating layer 30 (that is, the concentration of manganese oxide near the surface of the coating layer 30 is higher than the manganese oxide concentration near the interface of the coating layer 30 and the Sn-based plating layer 20). Concentration is great).

As a result, since the barrier effect produced by manganese oxide can be fully utilized, the yellowing resistance, the sulfide blackening resistance, and the corrosion resistance after painting are further improved. In addition, since the amount of manganese oxide in the interface between the coating layer 30 and the Sn-based plating layer 20 is small, the adhesion of the coating film is further improved.

In this state, specifically, for example, when the coating layer 30 is analyzed by X-ray photoelectron spectroscopy (XPS) in the depth direction, the depth position A where the concentration of the Mn element existing as the manganese oxide is the largest (in other words, the Mn element is The position with the greatest detection intensity) is located on the surface side of the coating layer 30 than the depth position B where the concentration of Zr element existing as a zirconium oxide is the greatest (in other words, the position with the greatest detection intensity of Zr element), and the depth position A and the depth position B The distance in the depth direction must be 2nm or more.

2 is a diagram showing an example of the element concentration profile in the thickness direction (depth direction) of the Sn-based plating layer 20 and the coating layer 30 of the Sn-based plated steel sheet 1 of the present embodiment. The element concentration profile shown in FIG. 2 was analyzed in the depth direction of XPS, and the element concentration distribution from the surface of the coating layer 30 through the Sn-based plating layer 20 to the surface of the steel plate 10 was measured. In FIG. 2, the position of “sputtering depth” 0 on the horizontal axis is the surface of the coating layer 30. The value of "sputtering depth" in Figure 2 is synonymous with "depth position".

In the example shown in FIG. 2, the depth position A is a position where the sputtering depth is 0 nm, and the depth position B is a position where the sputtering depth is 4.0 nm. If FIG. 1 is described with the example of FIG. 2, the depth position A is located on the surface of the coating layer 30 (above the coating layer 30 in FIG. 1), and the depth position B is located at a distance of 4 nm from the surface of the coating layer 30 in the depth direction (Figure (1) at a distance of 4 nm from the top of the coating layer 30 toward the bottom). That is, in the example shown in FIG. 2, the distance between the depth directions A and B is 4 nm.

At this time, usually, on the surface side of the coating layer 30 containing zirconium oxide and manganese oxide, there is more manganese oxide than zirconium oxide on a mass basis. The distance between the depth positions A and B in the depth directions of 2 nm or more means that the manganese oxide on the surface side of the coating layer 30 is more concentrated than the zirconium oxide. Therefore, the concentrated manganese oxide on the surface of the coating layer 30 becomes an oxide with a higher oxidation number, thereby becoming a coating with high barrier properties. Since the film composed of the manganese oxide suppresses the penetration of oxygen and sulfur, the generation of tin oxide and tin sulfide in the Sn-based plating layer can be suppressed. Therefore, the yellowing resistance or coating adhesion of the Sn-based plating layer can be improved, and the sulfide blackening resistance can be improved.

Furthermore, the depth position A where the concentration of the Mn element existing as a manganese oxide is the largest is preferably located on the surface side of the coating layer at a distance of 4 nm or more from the depth position B where the concentration of the Zr element existing as the zirconium oxide is the largest. If the distance between these depth positions is 4 nm or more, the concentration of manganese oxide on the surface of the coating layer 30 becomes more significant, and the coating composed of manganese oxide will further exert a barrier function. Here, the upper limit of the separation distance between the depth positions is not specifically defined, and the farther the better, but the actual upper limit is about 15 nm.

By analyzing the coating layer 30 by X-ray photoelectron spectroscopy (XPS) from the surface side, the distribution of zirconium oxide and manganese oxide in the coating layer 30 can be specified and quantified. Specifically, in the element concentration profile obtained by X-ray photoelectron spectroscopy, the bond energy peak position of Zr 3d5/2 is located on the higher energy side than the metal Zr bond energy and is 3.0eV or more and 4.0eV or less from the bond energy peak of Zr 3d5/2 , To specify the zirconium oxide in the coating layer 30. In addition, in the element concentration profile obtained by X-ray photoelectron spectroscopy, based on the bond energy peak of Mn 2p3/2 that exists on the higher energy side than the bond energy peak of metal Mn and is separated by 1.5 eV or more and 3.5 eV or less, Specify the manganese oxide in the coating layer 30.

Furthermore, the aforementioned Zr 3d2/5 or Mn 2p3/2 represents the energy level of electrons in Zr or Mn, which can be explained in the same way as the behavior of electrons in Sn described in P.83 in Non-Patent Document 1, for example.

Here, according to the above-mentioned measurement method, it is only necessary to measure the bond energy peak of Zr 3d5/2, which is located on the higher energy side than the metal Zr bond energy peak position related to zirconium oxide and is at a distance of 3.0 eV or more and 4.0 eV or less. "" and "The bond energy peak of Mn 2p3/2 that exists at a distance of 1.5 eV or more and 3.5 eV or less from the high energy side relative to metal Mn relative to manganese oxide", the coating layer 30 may also be Contain other structures of zirconium oxide or manganese oxide, or compounds other than oxides.

As shown in FIG. 2, it can be seen that the Sn-based plated steel sheet 1 of the present embodiment has a coating layer 30 in which zirconium oxide and manganese oxide coexist on the surface of the Sn-based plating layer 20 containing metal Sn.

Furthermore, the coating layer 30 containing zirconium oxide and manganese oxide may be in a mixed state of the two or a solid solution of the oxide, and its existence state is not limited. In addition, the coating layer 30 may also contain any elements such as Fe, Ni, Cr, Ca, Na, Mg, Al, and Si.

The oxide content (metal Zr content) and the manganese oxide content (metal Mn content) in the coating layer 30 are those obtained by immersing the Sn-based plated steel sheet 1 of the present embodiment in an acidic solution such as hydrofluoric acid and sulfuric acid, and then dissolving it. The dissolved solution is the value measured by chemical analysis such as Inductively Coupled Plasma (ICP) emission analysis method. Alternatively, the zirconium oxide content (metal Zr content) and the manganese oxide content (metal Mn content) in the coating layer 30 can also be measured by fluorescent X-rays. From the viewpoint of measurement accuracy and rapidity, it is better to use the fluorescent X-ray method in the industry.

The Sn-based plated steel sheet 1 of the present embodiment described above has a coating layer 30 containing a predetermined amount of zirconium oxide and manganese oxide on the Sn-based plating layer 20. In addition, the content of manganese oxide in the coating layer 20 is within a predetermined range relative to the content of zirconium oxide. Even, in the depth-direction elemental analysis using XPS, the depth position A where the concentration of Mn element existing as manganese oxide is the largest is higher than The depth position B where the concentration of the Zr element existing as the zirconium oxide is the largest is located on the surface side of the coating layer 30, and the depth direction distance between the depth position A and the depth position B is 2 nm or more. Therefore, the manganese oxide reduces the tin oxide existing near the coating layer 30 and reduces the tin oxide. On the other hand, if the manganese oxide becomes an oxide with a higher oxidation number, a coating with high barrier properties is formed and oxygen and sulfur are suppressed. Penetration. In addition, as the barrier properties of zirconium oxide are used in the coating layer 30, the generation of tin oxide and tin sulfide is reduced, the yellowing resistance or the adhesion of the coating film is improved, and the sulfide blackening resistance is also improved.

In addition, the Sn-based plated steel sheet 1 of the present embodiment can form a well-known film on the surface of the Sn-based plated steel sheet having the Sn-based plating layer 20 and the film layer 30 as described above. Examples of the film include various chemical conversion treatment films using P-based compounds, Al-based compounds, and the like. However, it is preferable that the Sn-based plated steel sheet 1 of the present embodiment is not subjected to chromate treatment. Therefore, the Sn-based plated steel sheet 1 of the present embodiment preferably does not have a chromate layer.

In addition, although the Sn-based plated steel sheet 1 having the Sn-based plating layer 20 only on one side has been described, the present invention is not limited thereto. For example, the Sn-based plated steel sheet 1 may have Sn-based plating layers 20 on both sides. At this time, the above-mentioned film layer 30 may be provided only on the Sn-based plating layer 20 on at least one side. In addition, the Sn-based plated steel sheet 1 may have a Sn-based plating layer 20 on one side and various coating films other than the Sn-based plating layer 20 on the other side.

>2. Manufacturing method of Sn series plated steel sheet> The Sn-based plated steel sheet of the present embodiment can be manufactured by any method. For example, it can be manufactured by the method of manufacturing the Sn-based plated steel sheet described below.

The manufacturing method of the Sn-based plated steel sheet 1 of the present embodiment includes the steps of forming a Sn-based plating layer 20 on at least one surface of the steel sheet 10, and forming a layer containing zirconium oxide and manganese oxide on the Sn-based plating layer 20的膜层30的步骤。 The steps of the skin layer 30. Hereinafter, a detailed description will be given.

(2.1 Preparation of steel plate) First, the steel sheet 10 as the base material of the Sn-based plated steel sheet 1 is prepared. The manufacturing method or material of the steel sheet used is not particularly specified, and for example, those that have undergone the steps of hot rolling, pickling, cold rolling, annealing, tempering rolling and the like after casting can be used.

(2.2 Formation of Sn plating layer) Next, a Sn-based plating layer (Sn plating) is formed on at least one surface of the steel sheet. The method of applying Sn-based plating on the surface of the steel sheet is not specifically specified, but the well-known plating method is preferred. The plating method can be used, for example, electroplating using known electroplating tinplate baths, halogen baths, alkaline baths, etc. . Furthermore, a melting method in which Sn-based plating is performed by immersing a steel sheet in molten Sn can also be used.

In addition, after Sn-based plating, a heat-melting treatment of heating the steel sheet with the Sn-based plating layer to 231.9°C or higher, which is the melting point of Sn, may also be performed. Through the heating and melting treatment, the surface of the Sn-based plating layer will show more gloss, and an alloy layer of Sn and Fe is formed between the Sn-based plating layer and the steel sheet, and the corrosion resistance or adhesion is improved.

(2.3 Formation of Coating Layer) Next, a coating layer containing zirconium oxide and manganese oxide is formed on at least a part of the surface of the Sn-based plating layer. Thereby, a Sn-based plated steel sheet of this embodiment can be obtained.

The coating layer containing zirconium oxide and manganese oxide can be formed on the surface of the Sn-based plating layer by performing the following treatments: immersing the Sn-based plated steel sheet in an immersion bath containing zirconium ions and manganese ions, or Cathodic electrolysis is performed in a catholyte containing zirconium ions and manganese ions. However, during the immersion treatment, a coating layer containing zirconium oxide and manganese oxide is formed by etching the surface of the Sn-based plating layer as the base. Therefore, the adhesion amount of the Sn-based plating layer tends to become uneven, and the processing time is also prolonged, which is not conducive to industrial production. On the other hand, in cathodic electrolysis, the surface cleaning by forced charge transfer and the hydrogen generated at the steel plate interface interacts with the adhesion promotion effect by pH increase, and a uniform film can be obtained. In addition, by coexisting nitrate ions and ammonium ions in the catholyte, the cathodic electrolysis treatment can be a short time treatment of several seconds to several tens of seconds. Therefore, the cathodic electrolysis treatment is extremely advantageous in industry.

Therefore, the formation of the film layer containing zirconium oxide and manganese oxide is preferably by the method of cathodic electrolysis.

The concentration of zirconium ions in the catholyte for cathodic electrolysis can be appropriately adjusted depending on the production equipment, production speed (capacity), etc. For example, the zirconium ion concentration is preferably 100 ppm or more and 4000 ppm or less. The manganese ion concentration is preferably 0.07 times or more and 2.50 times or less of the zirconium ion concentration. By setting the manganese ion concentration within the aforementioned range, a coating layer is formed such that the adhesion amount of zirconium oxide (metal Zr) is within the aforementioned range, whereby the adhesion amount of manganese oxide (metal Mn) is also within the aforementioned range.

In addition, the solution containing zirconium ions and manganese ions may contain other components such as fluoride ions, ammonium ions, nitrate ions, sulfate ions, and chloride ions.

For the supply source of zirconium ions in the catholyte, for example, zirconium complexes _{such as H 2} ZrF _{6 can be used.} As mentioned above, Zr in the Zr complexes becomes Zr ⁴⁺ and exists in the catholyte by increasing the pH at the cathode electrode interface. Such zirconium ions react more in the catholyte and become zirconium oxide. The supply source of manganese ions can be manganese sulfate, manganese nitrate, manganese chloride, etc. as examples.

In addition, as the catholyte solvent during the cathodic electrolysis treatment, water such as distilled water can be used, for example. However, the solvent may not be specified as water such as distilled water, and it may be appropriately selected depending on the substance to be dissolved, the formation method, and the like.

Furthermore, in order to adjust the pH of the catholyte or improve the efficiency of electrolysis, it is also possible to add, for example, nitric acid, ammonia, etc. to the catholyte.

Here, the temperature of the catholyte at the time of cathodic electrolysis is not particularly specified, but it is preferably set to a range of 10°C or more and 50°C or less, for example. By performing cathodic electrolysis below 50°C, a fine and uniform film layer structure formed of very fine particles can be formed. On the other hand, when the liquid temperature is less than 10°C, the film formation efficiency is poor, and it is necessary to cool the solution in the case of high outside temperature such as summer. Not only is it not economical, but the composition of the catholyte also causes sulfide blackening resistance. Declining situation. In addition, when the liquid temperature exceeds 50°C, the film formed by the composition of the catholyte is not uniform, causing defects, cracks, microcracks, etc., and it is difficult to form a fine film, which may become a starting point for corrosion.

In addition, the pH of the catholyte is not particularly limited, but it is preferably 3.0 or more and 5.0 or less. If the pH is less than 3.0, the film formation efficiency may decrease due to other conditions of the cathodic electrolysis treatment. If the pH exceeds 5.0, a large amount of precipitation may occur in the catholyte due to the composition of the catholyte, resulting in poor continuous productivity.

In addition, the current density during the cathodic electrolysis treatment is preferably set to, for example, 0.05 A/dm ² or more and 50.00 A/dm 2 or less. When the current density is less than 0.05 A/dm ² , the film formation efficiency may decrease due to other conditions of the cathodic electrolysis treatment, resulting in a thin film, and the yellowing resistance and sulfide black resistance may decrease. When the current density exceeds 50.00A/dm ² , there may be excessive hydrogen generation due to other conditions of cathodic electrolysis treatment, forming coarse zirconium oxide and manganese oxide, and poor yellowing resistance, coating film adhesion, and sulfide black resistance. Case. The preferred current density range is 1.00 A/dm ² or more and 10.00 A/dm ² or less.

In addition, when forming the film layer, the time of the cathodic electrolysis treatment is not particularly limited. Relative to the desired content of zirconium oxide in the coating layer (amount of metal Zr), the cathodic electrolysis treatment time can be appropriately adjusted depending on the current density. In addition, the current pattern during the cathodic electrolysis treatment may be continuous or intermittent energization.

Moreover, when analyzing the coating layer in the depth direction by X-ray photoelectron spectroscopy, in order to maximize the peak position of the detection intensity of manganese oxide, the peak position of the maximum detection intensity of the zirconium oxide exists on the surface layer of the coating layer. Side, and the distance is more than 2nm, after the cathodic electrolysis treatment, water washing by immersion treatment or spray treatment is required for 2~10 seconds.

By this water washing, the peak position of the maximum detection intensity of manganese oxide is more likely to exist on the surface side of the coating layer than the peak position of the maximum detection intensity of zirconium oxide. This mechanism is presumed to be that the low-pH catholyte solution after cathodic electrolysis is removed by sufficient water washing to suppress the Mn oxide deposited on the surface of the coating layer from dissolving in the catholyte solution adhering to the coating layer. In addition, it is estimated that washing with water has the effect of removing the zirconium oxide adhering to the surface of the coating layer. If the washing time is less than 2 seconds, Mn cannot be sufficiently concentrated on the surface of the coating layer. On the other hand, if the washing time exceeds 10 seconds, the surface layer of Mn is sufficiently concentrated, which only reduces the productivity in industrial production.

Furthermore, the aforementioned washing time is preferably 3 seconds or more, and more preferably 4 seconds or more. If the water washing time is 3 seconds or more, the depth position A where the concentration of the Mn element existing as a manganese oxide is maximized can be more reliably separated from the depth position B where the concentration of the Zr element existing as a zirconium oxide is the largest by 2 nm or more. Moreover, if the washing time is 4 seconds or more, the depth position A at which the concentration of Mn element existing as manganese oxide is the largest and the depth at which the concentration of Zr element existing as zirconium oxide is the largest without lowering the yield can be more reliably made The positions B are separated by 4 nm or more.

In addition, the washing time is preferably 8 seconds or less, and particularly preferably 6 seconds or less. If the water washing time is 8 seconds or less, the depth position A where the concentration of the Mn element existing as a manganese oxide is maximized can be more reliably separated from the depth position B where the concentration of the Zr element existing as a zirconium oxide is the largest by 2 nm or more. In addition, if the washing time is 6 seconds or less, the depth position A where the concentration of Mn element present as manganese oxide is maximized can be separated from the depth position B where the concentration of Zr element present as zirconium oxide is maximized without lowering the yield. 4nm.

In the above, the method of forming the film layer by one-stage cathodic electrolysis treatment or immersion treatment has been described. However, in the present invention, the method for forming the coating layer is not limited to the aforementioned method, and it is preferable to form the coating layer by a multi-stage cathodic electrolysis process.

For example, in this step, it is preferable to have the following treatments. (a) The first treatment is to immerse the Sn-based plated steel sheet in a first bath containing zirconium ions, or to perform the Sn-based plated steel sheet in the first bath Cathodic electrolysis treatment, followed by (b) second treatment, is to immerse the Sn-based plated steel sheet in a second bath containing manganese ions, or subject the Sn-based plated steel sheet to cathodic electrolysis in the second bath.

Thereby, when the coating layer is analyzed by X-ray photoelectron spectroscopy in the depth direction, a coating layer with the ratio of the zirconium oxide relative to the manganese oxide in the surface being 0 to 0.01 on a mass basis can be realized. That is, in the first treatment, a layer mainly composed of zirconium oxide is formed near the Sn-based plating layer, and in the second treatment, a layer mainly composed of zirconium oxide can be formed with manganese oxide as the main body的层。 The layer. Since the coating layer is composed of a layer of a film containing zirconium oxide and a film containing manganese oxide, the formation of zirconium oxide on the surface of the coating layer can be prevented, and a coating made of manganese oxide with high barrier properties The composition of the cladding. That is, in the coating layer, the concentration gradient of zirconium oxide and manganese oxide is generated in the thickness direction. Therefore, by combining the above-mentioned first treatment and second treatment, in the coating layer containing zirconium oxide and manganese oxide, a large amount of manganese oxide and zirconium oxide can be formed in order from the surface side of the coating layer. Floor.

In addition, by performing such cathodic electrolysis in multiple stages, the coating layer has a composition in which a film containing zirconium oxide and a film containing manganese oxide are laminated. Therefore, in the thickness direction of the coating layer, the depth position A where the concentration of the Mn element existing as a manganese oxide is the largest can be more reliably separated from the depth position B where the concentration of the Zr element existing as a zirconium oxide is the largest by 4 nm or more.

In the first treatment, the concentration of zirconium ions in the first bath (first catholyte) containing zirconium ions used can be appropriately adjusted depending on production equipment, production speed (capacity), and the like. For example, the zirconium ion concentration is preferably 100 ppm or more and 4000 ppm or less.

In addition, in order to increase the concentration of zirconium oxide in the formed coating layer, it is preferable that the first bath does not contain manganese ions or has a low content of manganese ions. Specifically, the manganese ion concentration in the first bath is preferably 10 ppm or less.

The other components of the first bath or the various conditions of the first treatment can be the same as the cathodic electrolysis treatment described above, so the description is omitted.

In the second treatment, the concentration of manganese ions in the second bath containing manganese ions (second catholyte) used can be appropriately adjusted depending on production equipment, production speed (capacity), and the like. The manganese ion concentration is preferably 30 ppm or more and 10,000 ppm or less.

In addition, in order to increase the concentration of manganese oxide in the formed coating layer, it is preferable that the second bath does not contain manganese ions or has a low content of zirconium ions. Specifically, the zirconium ion concentration in the second bath is preferably 100 ppm or less.

The other components of the second bath or the various conditions of the second treatment can be the same as the cathodic electrolysis treatment described above, so the description is omitted. In addition, after the first treatment and the second treatment, the water washing treatment may be performed separately.

As described above, the Sn-based plated steel sheet of the present embodiment can be manufactured. Furthermore, after the aforementioned steps, known treatments, such as washing, can also be appropriately carried out. [Example]

Next, while showing examples, the Sn-based plated steel sheet of the present invention will be specifically explained. In addition, the examples shown below are only an example of the Sn-based plated steel sheet of the present invention, and the Sn-based plated steel sheet of the present invention is not limited by the following examples.

>1. Method of making test materials> Explain the standard production method of test materials. In addition, the test materials of each example described later were made according to the method of making the test materials.

First, the low-carbon cold-rolled steel sheet with a thickness of 0.2mm is subjected to electrolytic alkali degreasing, water washing, immersion in dilute sulfuric acid pickling, and water washing as pretreatments, and then electroplating Sn series using a phenol sulfonic acid bath, and then heat melting treatment . Through these treatments, Sn-based plating layers are formed on both sides of the steel sheet. The adhesion amount of the Sn-based plating layer is about 2.8g/m ² per single side as the standard. Adjust the adhesion amount of the Sn-based plating layer by changing the energization time.

Next, the steel sheet on which the Sn-based plating layer is formed is treated by cathodic electrolysis in an aqueous solution (catholyte) containing zirconium fluoride and manganese nitrate to form a film containing zirconium oxide and manganese oxide on the surface of the Sn-based plating layer Floor. Adjust the temperature of the catholyte to 35°C, and the pH of the catholyte to be above 3.0 and below 5.0, and adjust the current density of the catholyte treatment appropriately according to the zirconium oxide content (metal Zr amount) in the desired coating layer And cathodic electrolysis treatment time.

>2. Evaluation method> The Sn-based plated steel sheet produced in this manner was subjected to various evaluations shown below.

[The amount of adhesion per side of the Sn-based plating layer (the amount of metal Sn in the Sn-based plating layer)] The adhesion amount per single side of the Sn-based plating layer (the amount of metal Sn in the Sn-based plating layer) is measured as follows. A test piece of a steel plate with a Sn-based plating layer with a large number of known metal Sn content was prepared. Next, the fluorescent X-ray intensity of metal Sn was measured from the surface of the Sn-based plating layer of the test piece by a fluorescent X-ray analyzer (ZSX Primus manufactured by Rigaku Corporation) on each test piece in advance. In addition, a calibration curve showing the relationship between the measured fluorescent X-ray intensity and the amount of metallic Sn is prepared. Then, the coating layer of the Sn-based plated steel sheet to be measured was removed, and a test piece in which the coating layer was not formed and the Sn-based plating layer was exposed was prepared. The fluorescent X-ray intensity of metal Sn is measured on the surface where the Sn-based plating layer is exposed by a fluorescent X-ray device. By using the obtained fluorescent X-ray intensity and the calibration curve prepared in advance, the adhesion amount per single side of the Sn-based plating layer (that is, the metal Sn content) is calculated.

In addition, the measurement conditions were X-ray source Rh, tube voltage of 50 kV, tube current of 60 mA, dispersive crystal LiF1, and measurement diameter of 30 mm.

[The existence of zirconium and manganese in the coating] In order to confirm the presence of Zr and Mn in the coating layer as zirconium oxide and manganese oxide, respectively, XPS (PHI Quantera SXM manufactured by ULVAC-PHI) was performed on the surface of the coating layer to investigate Zr 3d5/ of the zirconium oxide in the coating layer. 2. And the peak position of the bond energy of Mn 2p3/2. The measurement conditions were as follows: X-ray source mono-AlKα line (hν=1466.6eV, 100.8W), X-ray diameter 100μmφ, detection depth several nm (grazing angle 45°), analysis range 1400×100μm. In addition, if the peak position of the bond energy of Zr 3d5/2 is on the higher energy side than the peak position of the bond energy of metal Zr (=484.9eV) and the distance is 3.0eV or more and 4.0eV or less, it is defined as the presence of oxides zirconium. In addition, if the peak position of the bond energy of Mn 2p3/2 is on the higher energy side than the peak position of the bond energy of metal Mn and is 1.5 eV or more and 3.5 eV or less, it is defined as the presence of manganese as an oxide.

[Content of zirconium oxide in coating layer (amount of metal Zr)] The content of zirconium oxide (amount of metal Zr) in the coating layer was measured according to the method for measuring the amount of adhesion per single side of the Sn-based plating layer (the amount of metal Sn in the Sn-based plating layer). That is, a test piece of the Sn-based plated steel sheet to be measured is prepared. On the surface of the coating layer of the test piece, the fluorescence X-ray intensity from the metal Zr was measured with a fluorescent X-ray analyzer (ZSX Primus manufactured by Rigaku Corporation). The content of zirconium oxide in the coating layer (amount of metal Zr) is calculated by using the obtained fluorescent X-ray intensity and a calibration curve related to metal Zr prepared in advance.

[The content of manganese oxide in the coating layer (amount of metal Mn)] The content of manganese oxide (metal Mn content) in the coating layer was measured according to the method of measuring the amount of adhesion per single side of the Sn-based plating layer (the amount of metal Sn in the Sn-based plating layer). That is, a test piece of the Sn-based plated steel sheet to be measured is prepared. On the surface of the coating layer of the test piece, the fluorescence X-ray intensity derived from metal Mn was measured with a fluorescent X-ray analyzer (ZSX Primus manufactured by Rigaku Corporation). The content of manganese oxide (metal Mn content) in the coating layer is calculated by using the obtained fluorescent X-ray intensity and a calibration curve related to metal Zr prepared in advance.

[Distribution of zirconium oxide and manganese oxide in the film layer] The distribution of zirconium oxide and manganese oxide in the coating layer was measured by XPS (PHI Quantera SXM manufactured by ULVAC-PHI). Specifically, a test piece of a Sn-based plated steel sheet to be measured is prepared. From the surface of the film layer of the test piece, the thickness direction (depth direction) analysis using XPS (PHI Quantera SXM manufactured by ULVAC-PHI) was performed, and Sn existed as tin oxide, Sn existed as metal Sn, and existed as zirconium oxide. Calculate the element concentration of each oxide and the metal element manganese oxide with the sum of the element concentrations of Zr, Zr as metal Zr, Mn as manganese oxide and Mn as metal Mn.

Furthermore, the measurement conditions were set as X-ray source mono-AlKα line (hν=1466.6eV, 100.8W), X-ray diameter 100μmφ, detection depth several nm (grazing angle 45°), analysis range 1400×100μm, electron gun 1.0V , 20μA, sputtering conditions Ar+, acceleration voltage 1kV, sputtering speed 1.5nm/min (SiO ₂ conversion value). In the aforementioned XPS measurement, the peak position of the highest detection intensity of manganese oxide is 4nm or more closer to the surface of the coating layer than the peak position of the highest detection intensity of zirconium oxide is marked as "A", and the peak position is 2nm closer to the surface of the coating layer In the above, the case of less than 4nm is marked as "B", and the case of none is marked as "C".

[Yellowing resistance] Place the test material of the Sn-based plated steel sheet in a constant temperature and humidity bath maintained at 40°C and a relative humidity of 80% for 4 weeks, perform a wetness test, and obtain the amount of change △b* of the color difference b* value before and after the wetness test Evaluation. If △b* is 1 or less, it is set to "A", more than 1 and 2 or less is set to "B", more than 2 and 3 or less is set to "C", and if it exceeds 3, it is set to "NG". Set the evaluations "A", "B" and "C" to pass. b*Measured using the commercially available color difference meter SUGA test mechanism SC-GV5. The measurement conditions for b* are light source C, total reflection, and measurement diameter of 30 mm.

[Coating film adhesion] The coating film adhesion was evaluated as follows. The Sn-based plated steel sheet of the test material plating to [Yellowing Resistance] After the wet test methods described, was coated on the dry mass 7g / m ² of the tank with a commercially available epoxy resin coating, baked at 200 ℃ 10 minutes. Leave at room temperature for 24 hours. After that, the obtained Sn-based plated steel sheet was scratched out of grid-like scratches (7 scratches each at 3 mm in the vertical and horizontal directions) that reached the surface of the steel plate, and evaluated by a tape peeling test on the part. If the coating film is not completely peeled off at the area where the tape is attached, set it as "A". If peeling of the film is found around the scratches on the mesh, set it as "B". If peeling of the film is found in the grid square, set it as "NG"". Set the evaluation "A" and "B" to pass.

[Sulfur blackening resistance] The sulfide blackening resistance was evaluated as follows. The surface of the test material of the Sn-based plated steel sheet produced by the method described in the aforementioned [Yellowing resistance] and after the wet test was coated with a ^{commercial epoxy resin coating of 7g/m 2} in dry mass for cans, and then heated at 200°C Roast for 10 minutes and place at room temperature for 24 hours. After that, the obtained Sn-based plated steel sheet was cut into a predetermined size and immersed in an aqueous solution composed of 0.3% sodium dihydrogen phosphate, 0.7% sodium hydrogen phosphate, and 0.6% L-cysteine hydrochloride In, 121 ℃ in a sealed container. The 60-minute distillation treatment was evaluated from the appearance after the test. If there is no change in appearance before and after the test, set it as "A", if a slight (10% or less) blackening is found, set it as "B", and if blackening is found in an area exceeding 10% of the test surface, set it as "NG". Set the evaluations "A" and "B" as pass.

[Corrosion resistance after painting] The corrosion resistance after painting was evaluated as follows. The surface of the test material of the Sn-based plated steel sheet produced by the method described in the aforementioned [Yellowing resistance] and after the wet test was coated with a ^{commercial epoxy resin coating of 7g/m 2} in dry mass for cans, and then heated at 200°C Roast for 10 minutes and place at room temperature for 24 hours. After that, the obtained Sn-based plated steel sheet was cut into a predetermined size and immersed in commercially available tomato juice at 60°C for 7 days, and then the presence or absence of rust was visually evaluated. If rust is not found at all, set it as "A", if rust is found to be less than 10% of the total area of the test surface, set it as "B", and if rust is found to be greater than 10% of the entire test surface, set it as "NG". Set the evaluation "A" and "B" to pass.

>3. Example 1> According to the method described in the above>1. Preparation method of test material>, the adhesion amount of zirconium oxide and manganese oxide was changed, and Sn-based plated steel sheet was manufactured.

The well-known electroplating tinplate bath produces Sn plating by electrolysis. Change the amount of energization during electrolysis, so that the amount of Sn deposited is above 0.05g/m ² and within the range of 20g/m ^2. In addition, both the test piece subjected to the heating and melting treatment after Sn plating and the unimplemented test piece were produced.

When forming a film containing zirconium oxide and manganese oxide on the surface of Sn plating, cathodic electrolysis of Sn-based plated steel sheet in an aqueous solution with a zirconium ion concentration of 50 ppm or more and 5000 ppm or less, and a manganese ion concentration of 3.5 ppm or more and 12500 ppm or less. A coating layer containing various zirconium oxides and manganese oxides is formed on the plated steel sheet. The pH of the aforementioned treatment liquid for forming the film was set to 3.8, and the liquid temperature was set to 35°C, and the amount of energization was appropriately changed. In addition, the immersion water washing time after the cathodic electrolysis treatment was changed from 1 to 10 seconds.

Through the above, a test piece of Sn-based plated steel sheet of A1 to A25 and a1 to a7 with the adhesion amount of zirconium oxide and manganese oxide changed was obtained. Furthermore, in any test piece, the zirconium and manganese contained in the film were confirmed by XPS to be respectively the zirconium oxide and manganese oxide specified in the present invention. Table 1 shows the results of various performance evaluations performed on the aforementioned test pieces.

[Table 1]

It can be seen from the foregoing Table 1 that the performance of the Sn-based plated steel sheets of the present invention A1 to A25 are all good. In particular, when the amount of Sn plating adhesion, the amount of Zr oxide, and the amount of manganese oxide are in a preferable range, the performance is more excellent. On the other hand, it can be seen that Comparative Examples a1 to a7 are inferior in any of yellowing resistance, coating film adhesion, sulfide blackening resistance, and corrosion resistance after painting.

>4. Example 2> Next, according to the method described in >1. Preparation method of test material>, the distribution of zirconium oxide and manganese oxide in the coating layer was changed, and a Sn-based plated steel sheet was produced.

The well-known electroplating tinplate bath produces Sn plating with an electrolytic method so that the adhesion amount of Sn is 2.8 g/m ^2.

After that, the Sn-based plated steel sheet was cathodicly electrolyzed in an aqueous solution containing no manganese ions but containing zirconium ions (first treatment), and then washed with water for the washing time shown in Table 2 below, and then after no zirconium ions but containing manganese ions Cathodic electrolysis in the aqueous solution (the second treatment) to produce test pieces B1 to B6. In addition, in the same manner as in Example 1, cathodic electrolysis was carried out in an aqueous solution containing zirconium ions and manganese ions, and washed with water for the washing time shown in Table 2 below to prepare test piece B7.

Through the above, a test piece of B1-B7 Sn-based plated steel sheet with a change in the distribution of zirconium oxide and manganese oxide in the coating layer was obtained.

The distribution of zirconium oxide and manganese oxide in the film layer in the prepared test piece was measured by XPS (PHI Quantera SXM manufactured by ULVAC-PHI). Specifically, a test piece of a Sn-based plated steel sheet to be measured is prepared. From the surface of the film layer of the test piece, the thickness direction (depth direction) analysis using XPS (PHI Quantera SXM manufactured by ULVAC-PHI) was performed, and Sn existed as tin oxide, Sn existed as metal Sn, and existed as zirconium oxide. Calculate the element concentration of each oxide and the metal element manganese oxide with the sum of the element concentrations of Zr, Zr as metal Zr, Mn as manganese oxide and Mn as metal Mn.

In the aforementioned XPS measurement, the peak position of the highest detection intensity of manganese oxide is 4nm or more closer to the surface of the coating layer than the peak position of the highest detection intensity of zirconium oxide is marked as "A", and the peak position is 2nm closer to the surface of the coating layer In the above, the case of less than 4nm is marked as "B", and the case of none is marked as "C".

In addition, the ratio of the abundance of the zirconium oxide with respect to the manganese oxide of the outermost layer is set to "A" when it is 0 to 0.01 on a mass basis, and it is set to "B" when it is not.

In addition, the measurement conditions are as follows: X-ray source mono-AlKα line (hν=1466.6eV, 100.8W), X-ray diameter 100μmφ, detection depth several nm (grazing angle 45°), analysis range 1400×100μm, electron gun 1.0V, 20μA, sputtering conditions Ar+, acceleration voltage 1kV, sputtering speed 1.5nm/min (SiO ₂ conversion value). Table 2 shows the results of various performance evaluations performed on the aforementioned test pieces.

[Table 2]

From Table 2 above, it can be seen that the case where the coating layer is formed by two cathodic electrolysis treatments (B1~B6) is more resistant to yellowing and the coating film is denser than the case where the coating layer is formed by one cathodic electrolysis treatment (B7). Adhesion, resistance to sulfide blackening, and good corrosion resistance after painting.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited by this example. As long as it is a person with ordinary knowledge in the technical field to which the present invention belongs, various changes or amendments that can be thought of within the scope of the technical ideas described in the scope of the patent claim are clear, and they can also be known that they should belong to the technical scope of the present invention. Industrial availability

As mentioned above, the Sn-based plated steel sheet of the present invention does not require the conventional chromate treatment, and has excellent yellowing resistance, coating film adhesion, and sulfide blackening resistance. It can be used as an environment-friendly can material and is widely used in Food cans, beverage cans, etc., have extremely high industrial use value.

1: Sn series plated steel sheet 10: Steel plate 20: Sn-based plating layer 30: Coating layer

Fig. 1 is an explanatory diagram schematically showing an example of the structure of a Sn-based plated steel sheet according to an embodiment of the present invention. Fig. 2 is an example of the element concentration profile in the thickness direction (depth direction) measured by X-ray photoelectron spectroscopy of the Sn-based plating layer and the coating layer of the Sn-based plated steel sheet according to an embodiment of the present invention.

Claims (7)

A Sn-based plated steel sheet having: a steel sheet; a Sn-based plating layer on at least one surface of the aforementioned steel sheet; and a coating layer on the aforementioned Sn-based plating layer; the aforementioned Sn-based plating layer is converted to metal Sn Sn containing 0.10 g/m ² or more and 15.00 g/m ² or less per single side; The coating layer contains zirconium oxide and manganese oxide; The content of the zirconium oxide in the coating layer is calculated as per metal Zr 0.20 mg/m ² or more and 50.00 mg/m ² or less on one side; relative to the content of the metal Zr of the zirconium oxide, the content of the metal Mn of the manganese oxide in the film layer is 0.01 times on a mass basis Above and 0.50 times or less; In the depth-direction elemental analysis by X-ray photoelectron spectroscopy, the depth position A where the concentration of Mn element existing as the aforementioned manganese oxide is the largest is greater than the depth where the concentration of Zr element existing as the aforementioned zirconium oxide is the largest The position B is located on the surface side of the film layer, and the depth direction distance between the depth position A and the depth position B is 2 nm or more. The Sn-based plated steel sheet of claim 1, wherein in the surface of the coating layer, the quality of the zirconium oxide in the depth-direction elemental analysis by X-ray photoelectron spectroscopy is the depth-direction element by X-ray photoelectron spectroscopy In the analysis, the mass of the aforementioned manganese oxide is less than 0.01 times. The Sn-based plated steel sheet of claim 1 or 2, wherein the depth direction distance between the aforementioned depth position A and the aforementioned depth position B is 4 nm or more. The request to any of items 1 to item 31 of the Sn-based plated steel sheet, wherein the content of zirconium oxide of the coating layer to the metal in terms of Zr per side 1.00mg / m ² or more and 30.00mg / m ² the following. The Sn-based request as described in any one of 1 to 4, the coated steel sheet, wherein the content of zirconium oxide of the coating layer to the metal in terms of Zr per side 2.00mg / m ² or more and 10.00mg / m ² the following. Such as the Sn-based plated steel sheet of any one of claims 1 to 5, wherein the content of the metal Mn of the manganese oxide in the coating layer is calculated on a mass basis relative to the content of the metal Zr of the zirconium oxide 0.05 times or more and 0.40 times or less. Such as the Sn-based plated steel sheet of any one of claims 1 to 6, wherein the content of the metal Mn of the manganese oxide in the coating layer is calculated on a mass basis relative to the content of the metal Zr of the zirconium oxide 0.10 times or more and 0.20 times or less.

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