WO2015020053A1

WO2015020053A1 - Steel sheet for container

Info

Publication number: WO2015020053A1
Application number: PCT/JP2014/070620
Authority: WO
Inventors: 幹人須藤; 中村　紀彦; 安秀大島; 智文重國; 威鈴木
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2013-08-08
Filing date: 2014-08-05
Publication date: 2015-02-12
Also published as: TW201510280A; JPWO2015020053A1; CN105452531A; JP6052305B2; PH12016500254B1; KR101760729B1; KR20160031508A; CN105452531B; PH12016500254A1; TWI557273B

Abstract

　Provided is a steel sheet for a container, said steel sheet having excellent film adhesion properties and paint adhesion properties. The steel sheet for a container has: a plated steel sheet having a plating layer that comprises at least one layer selected from among an Ni layer, an Sn layer, an Ni-Fe alloy layer, an Fe-Sn-Ni alloy layer, and an Fe-Sn alloy layer, and covers at least a portion of the surface of the steel sheet; and a coating film arranged on the plating layer-side surface of the plated steel sheet. The coating film has Ti and Ni, and the mass ratio (Ni/Ti) of Ni to Ti in the coating film is less than 1.0. The coating film deposition amount in terms of Ti is at least 5.0 mg/m² but less than 60.0 mg/m² per surface of the plated steel sheet, and the deposition amount in terms of Ni is more than 3.0 mg/m² per surface of the plated steel sheet. The S value as defined in a specific formula (1) is 1.00 or less.

Description

Steel plate for containers

The present invention relates to a steel plate for containers.

As a steel sheet (container steel sheet) used for containers such as cans, for example, Patent Document 1 discloses that “at least one surface of a steel sheet is Ni layer, Sn layer, Fe—Ni alloy layer, Fe—Sn alloy layer and Fe— It has a corrosion-resistant film composed of at least one layer selected from Ni—Sn alloy layers, includes Ti on the corrosion-resistant film, and further selected from Co, Fe, Ni, V, Cu, Mn, and Zn. A surface-treated steel sheet having an adhesive film containing 0.01 to 10 in total as a mass ratio with respect to at least one of these is disclosed ([Claim 1]).

JP 2010-031348 A

As a result of studying the steel plate for containers (surface-treated steel plate) described in Patent Document 1, the present inventors have found that under specific test conditions, adhesion to a PET film (hereinafter also referred to as “film adhesion”) and It was found that the adhesion to the paint (hereinafter also referred to as “paint adhesion”) may be insufficient.
This invention is made | formed in view of the above point, and it aims at providing the steel plate for containers which is excellent in film adhesiveness and paint adhesiveness.

As a result of intensive studies to achieve the above object, the present inventors have formed a film containing a specific amount of Ti and Ni, so that the film adhesion and paint adhesion of the resulting steel plate for containers can be improved. As a result, the present invention was completed.

That is, the present invention provides the following (I) to (VI).
(I) A plating layer comprising at least one layer selected from a Ni layer, a Sn layer, a Ni—Fe alloy layer, a Fe—Sn—Ni alloy layer, and a Fe—Sn alloy layer covering at least a part of the surface of the steel sheet A steel plate for containers having a plated steel plate and a coating disposed on the surface of the plated steel plate on the plating layer side, wherein the coating has Ti and Ni, and Ni and Ti of the coating the weight ratio of (Ni / Ti) is less than 1.0, the coating deposition amount of Ti converted per one surface of the plated steel sheet is less than 5.0 mg / m ² or more 60.0 mg / m ² The steel plate for containers whose nickel conversion amount per one side of the said plated steel plate is more than 3.0 mg / m < ² >, and whose S value defined by Formula (1) mentioned later is 1.00 or less.
(II) The said steel film is a steel plate for containers as described in said (I) whose said S value is less than 0.30.
(III) The said steel film is a steel plate for containers as described in said (I) whose said S value is 0.30 or more and 1.00 or less.
(IV) The steel sheet for containers according to any one of the above (I) to (III), wherein the coating film has an amount of adhesion in terms of Ti per side of the plated steel sheet of 10.0 to 30.0 mg / m ^2. .
(V) The steel plate for containers according to any one of (I) to (IV) above, wherein the T value defined by the formula (2) described later is 0.50 or less.
(VI) The steel plate for containers according to any one of (I) to (V) above, wherein the plating layer is a tin plating layer, and the coating contains a Ni—Sn alloy phase.

According to the present invention, a steel plate for containers having excellent film adhesion and paint adhesion can be provided.

It is a schematic diagram explaining a 180 degree | times peel test.

[Steel plate for containers]
The steel plate for containers of the present invention generally has a plated steel plate and a film disposed on the surface of the plated steel plate on the plating layer side.
Then, the inventors of the present invention contain a specific amount of Ti and Ni, and further satisfy the S value defined by the formula (1) described later satisfying 1.00 or less, whereby the film adhesion and It has been found that the paint adhesion is excellent.
Here, as will be described later, the S value defined by the formula (1) is an index indicating the amount of Ni existing on the surface side of the film, but the present inventors need a certain amount of Ni in the film. However, it has been found that when Ni is excessively present on the surface side of the film, film adhesion and paint adhesion are deteriorated. The mechanism (reason) is not clear, but if a certain amount of Ni is present in the film containing Ti (however, the mass ratio (Ni / Ti) is less than 1.0), the film is formed or the film is bonded to the steel sheet. On the other hand, if excessive Ni is present on the surface side of the film, it is considered that Ni precipitates in the form of particles and prevents adhesion between the film and the film or paint.
Note that the above mechanism is speculative, and it is assumed that the mechanism other than the above mechanism is within the scope of the present invention.

Hereinafter, specific aspects of the plated steel sheet and the coating will be described in detail. First, the aspect of a plated steel plate is explained in full detail.

[Plated steel sheet]
The plated steel sheet is at least one layer selected from a steel sheet and a Ni layer, a Sn layer, a Ni—Fe alloy layer, a Fe—Sn—Ni alloy layer, and a Fe—Sn alloy layer covering at least a part of the surface of the steel sheet. And a plating layer.
As a raw steel plate, a general steel plate for cans can be used. A plating layer is a layer which covers at least one part on the steel plate surface, A continuous layer may be sufficient and a discontinuous island shape may be sufficient as it. Moreover, the plating layer should just be provided in the at least single side | surface of the steel plate, and may be provided in both surfaces. The plating layer can be formed by a known method according to the contained element.
Below, the suitable aspect of a steel plate and a plating layer is explained in full detail.

<steel sheet>
The kind of steel plate is not particularly limited, and a steel plate (for example, a low carbon steel plate or an extremely low carbon steel plate) that is usually used as a container material can be used. The manufacturing method and material of the steel plate are not particularly limited, and the steel plate is manufactured through processes such as hot rolling, pickling, cold rolling, annealing, temper rolling, etc. from a normal slab manufacturing process.

If necessary, a steel sheet having a nickel (Ni) -containing layer formed on the surface thereof may be used, and a tin plating layer to be described later may be formed on the Ni-containing layer. By performing tin plating using a steel sheet having a Ni-containing layer, a tin plating layer containing island-shaped Sn can be formed, and weldability is improved.
The Ni-containing layer only needs to contain nickel, and examples thereof include a Ni plating layer (Ni layer) and a Ni—Fe alloy layer.
The method for applying the Ni-containing layer to the steel sheet is not particularly limited, and examples thereof include a known method such as electroplating. Further, when a Ni—Fe alloy layer is applied as the Ni-containing layer, the Ni diffusion layer can be coordinated by forming Ni on the steel sheet surface by electroplating and then annealing, thereby forming a Ni—Fe alloy layer.
The amount of Ni in the Ni-containing layer is not particularly limited, and is preferably 50 to 2000 mg / m ² as the Ni conversion amount per side. If it is in the above-mentioned range, it is more excellent in resistance to sulfur blackening and is advantageous in terms of cost.

<Plating layer>
As a plating layer which a plated steel plate has on the steel plate surface, a tin plating layer containing Sn is preferable. The tin plating layer only needs to be provided on at least one side of the steel plate, and may be provided on both sides.
The Sn adhesion amount per one surface of the steel sheet in the tin plating layer is preferably 0.1 to 15.0 g / m ² . When the Sn adhesion amount is within the above range, the outer appearance characteristics and corrosion resistance of the steel plate for containers are excellent. Among these, 0.2 to 15.0 g / m ² is more preferable in terms of these characteristics being more excellent, and 1.0 to 15.0 g / m ² is further preferable in terms of excellent workability.

Note that the Sn adhesion amount can be measured by surface analysis by a coulometric method or fluorescent X-ray. In the case of fluorescent X-rays, a calibration curve relating to the Sn amount is specified in advance using a Sn deposition amount sample with a known Sn amount, and the Sn deposition amount is relatively identified using the calibration curve.

The tin plating layer is a layer covering at least a part on the surface of the steel plate, and may be a continuous layer or a discontinuous island shape.

As the tin plating layer, in addition to the tin plating layer composed of the Sn layer obtained by plating tin, the lowermost layer of the Sn layer (Sn layer / steel sheet interface) obtained by heating and melting tin by electric heating after tin plating, etc. ) Includes a tin plating layer in which a part of the Fe—Sn alloy layer is formed, or a tin plating layer in which all of the Sn layers are alloyed to form an Fe—Sn alloy layer.
In addition, as the tin plating layer, the lowermost layer of the Sn layer (Sn layer / steel plate interface) obtained by tin-plating a steel plate having a Ni-containing layer on the surface and further heating and melting tin by electric heating or the like In addition, a tin plating layer in which an Fe—Sn—Ni alloy layer, an Fe—Sn alloy layer, or the like is partially formed, or a tin plating layer in which all Sn of the Sn layer is alloyed to form an Fe—Sn alloy layer is also included.

As a manufacturing method of a tin plating layer, a known method (for example, an electroplating method or a method of plating by immersing in molten Sn) may be mentioned.
For example, a phenol sulfonic acid tin plating bath, a methane sulfonic acid tin plating bath, or a halogen-based tin plating bath is used, and the adhesion amount per one surface is adjusted to a predetermined amount (for example, 2.8 g / m ² ) on the steel plate surface. After electroplating Sn, a reflow process is performed at a temperature equal to or higher than the melting point of Sn (231.9 ° C.) to alloy all Sn in the bottom layer of the Sn plating layer (Sn layer) or the Sn layer. A tin plating layer on which an alloy layer is formed can be manufactured. When the reflow process is omitted, a tin plating layer can be produced.

When the steel sheet has a Ni-containing layer on its surface, tin plating is performed on the Ni-containing layer to form a Sn layer, and when reflow treatment is performed, the lowermost layer (Sn layer) of the tin simple plating layer (Sn layer) Layer / steel interface) or all Sn in the Sn layer is alloyed to form an Fe—Sn—Ni alloy layer, an Fe—Sn alloy layer, or the like.

[Coating]
Next, the film | membrane arrange | positioned on the surface by the side of the plating layer of the plated steel plate mentioned above is demonstrated. The film is roughly a film containing Ti (titanium element) and Ni (nickel element) as its components, and is formed using a treatment liquid described later.

The coating has a Ti-equivalent adhesion amount (hereinafter also referred to as “Ti adhesion amount”) per side of the plated steel sheet of 5.0 mg / m ² or more and less than 60 mg / m ² . If the Ti adhesion amount is less than 5.0 mg / m ² or 60 mg / m ² or more, the film adhesion and paint adhesion are inferior, but if it is 5.0 mg / m ² or more and less than 60 mg / m ² , the film adhesion and Excellent paint adhesion. Ti adhesion amount, for the reason that the film adhesion and coating adhesion more excellent, preferably 10 ~ 30mg / m ^2, more preferably 15 ~ 25mg / m ^2.

In addition, the coating has an Ni conversion amount (hereinafter also referred to as “Ni adhesion amount”) per side of the plated steel sheet of more than 3.0 mg / m ² . When the Ni adhesion amount is 3.0 mg / m ² or less, the film adhesion is inferior, but when it exceeds 3.0 mg / m ² , the film adhesion is excellent. The Ni adhesion amount is preferably more than 3.0 mg / m ^{2 and} 10.0 mg / m ² or less, more preferably more than 3.0 mg / m ^{2 and} 5.0 mg / m ² or less because the adhesion between the film and the plated steel sheet is excellent. Is more preferable.

The amount of Ti adhesion and the amount of Ni adhesion are measured by surface analysis using fluorescent X-rays.
Ti, Ni, and the like in the film are included as various titanium compounds and nickel compounds, respectively, and the types and aspects of these compounds are not particularly limited.
However, when Ni is included as the plating layer, it is difficult to measure only the amount of Ni deposited in the film by the surface analysis using the fluorescent X-ray. In that case, the amount of Ni deposited in the film can be determined by combining cross-sectional observation with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) and glow discharge emission analysis. The amount of Ni contained in the plating layer can be distinguished.
Specifically, the cross section of the film and the plating layer is exposed by focused ion beam (FIB) processing, and the thickness of the film layer is calculated from cross-sectional observation by SEM or TEM.
Next, the relationship between the sputtering depth and the sputtering time by glow discharge emission analysis is obtained. Thereafter, the integrated emission count value by Ni element of the glow discharge emission analysis up to the sputtering time corresponding to the film thickness is obtained. From the integrated emission count value of the Ni element, the Ni adhesion amount can be obtained using a calibration curve obtained in advance.
Here, the calibration curve is created by the following method.
First, glow discharge emission analysis is performed on a plurality of samples having a coating film containing Ni on a plating layer not containing Ni and having different Ni adhesion amounts, and a count integrated value up to a sputtering time at which no emission count due to Ni element is detected is obtained. . Next, the Ni adhesion amount of these samples is obtained by surface analysis using fluorescent X-rays. In this way, a calibration curve between the Ni count integrated value and the Ni adhesion amount by glow discharge emission analysis is created.

The mass ratio (Ni / Ti) of Ni and Ti in the coating is less than 1.0. When the mass ratio (Ni / Ti) is 1.0 or more, Ni is likely to be present on the surface side of the film, and Ni is precipitated in a particulate form to prevent adhesion between the film and the film or paint, If the said mass ratio (Ni / Ti) is less than 1.0, it is excellent in film adhesiveness and paint adhesiveness.
The mass ratio (Ni / Ti) is preferably less than 0.9 and more preferably less than 0.8 because film adhesion and paint adhesion are more excellent. In addition, although a lower limit is not specifically limited, For example, 0.1 or more is mentioned.

The film has an S value defined by the following formula (1) of 1.00 or less.
S = [Is (Ni) / It (Ti)] / C ² (1)
In the formula (1), Is (Ni) is the amount of Ni per one side of the plated steel sheet calculated from the glow discharge emission analysis of Ni from the surface of the coating (surface opposite to the plated steel sheet) to a depth of 10 nm ( (Unit: mg / m ² ) (hereinafter also simply referred to as “Ni amount”).
It (Ti) represents the Ti amount (unit: mg / m ² ) (hereinafter also simply referred to as “Ti amount”) per one side of the plated steel sheet calculated from the glow discharge emission analysis of Ti of the entire coating.

The S value defined by equation (1) is an index indicating the amount of Ni existing on the surface side of the film, and the smaller the value, the smaller the amount of Ni on the film surface side and the greater the amount of Ti. The inventors have found that the film adhesion and paint adhesion of the resulting steel plate for containers is excellent when the S value is 1.00 or less, as shown in [Example] described later. It was.

The S value is not particularly limited as long as it is 1.00 or less. However, when the S value is less than 0.30 and the S value is 0.30 or more and 1.00 or less, the former is The reason is that the paint adhesion is better than the latter, and the latter is preferred because the film adhesion is better than the former.

The glow discharge emission analysis was conducted under the following conditions.
・ Device: GDA750 manufactured by Rigaku Corporation
・ Anode inner diameter: 4mm
・ Analysis mode: High frequency low voltage mode ・ Discharge power: 40W
・ Control pressure: 2.9 hPa
Detector: Photomultiplier Detection wavelength: Ni = 341.4 nm, Ti = 365.4 nm

In order to obtain the Ni amount from the glow discharge emission analysis of Ni up to a depth of 10 nm from the surface of the film, separately obtain the relationship between the sputtering depth and the sputtering time by glow discharge emission analysis, and obtain the glow discharge up to the sputtering time corresponding to 10 nm. What is necessary is just to obtain a count integrated value of emission analysis, measure a sample with a known adhesion amount, and create a calibration curve.
In addition, in order to obtain the Ti amount from the glow discharge emission analysis of Ti of the entire film, the count integrated value until the sputtering time when the count of the glow discharge emission analysis by Ti in the film is not detected is obtained, and a sample with a known adhesion amount is obtained. Measure and create a calibration curve.

The thickness of the film is preferably 10 to 120 nm, more preferably 20 to 60 nm. The thickness of the film can be measured from a cross-sectional profile obtained by observation with a transmission electron microscope (TEM) after exposing the cross section of the film by focused ion beam (FIB) processing.

Further, the film preferably has a T value defined by the following formula (2) of 0.50 or less.
T = [Ii (F) −Ib (F)] / Ib (F) (2)
In formula (2), Ii (F) represents the F peak count number of fluorescent X-ray analysis of the film before dipping the steel plate for containers of the present invention in boiling water for 30 minutes, and Ib (F) represents the present invention. The F peak count number of the fluorescent X-ray analysis of the film | membrane after immersing the steel plate for containers of for 30 minutes in boiling water is represented.

Here, [Ii (F) −Ib (F)] indicates the amount of F eluted by immersion in boiling water, and the T value defined by the equation (2) obtained by dividing this by Ib (F) is: It becomes an index indicating the ratio of the soluble F amount in the film. The present inventors have found that the film adhesion of the obtained steel sheet for containers is more excellent when the T value is 0.50 or less, as shown in [Example] described later.

The X-ray fluorescence analysis was performed under the following conditions.
Apparatus: X-ray fluorescence analyzer System 3270 manufactured by Rigaku Corporation
・ Measurement diameter: 30mm
・ Measurement atmosphere: Vacuum ・ Spectrum: F-Kα
・ Slit: COARSE
-Spectral crystal: TAP
The peak count of F-Kα in the fluorescent X-ray analysis of the film measured under the above conditions was used.

In the case where the plating layer is the above-described tin plating layer, the coating preferably contains a Ni—Sn alloy phase.
“Ni” in the Ni—Sn alloy phase is derived from Ni in the film, and “Sn” is derived from Sn in the tin plating layer. Such a Ni—Sn alloy phase may be deposited as a continuous layer in the film at the interface between the film and the tin plating layer, or may be intermittently deposited as particles dispersed in the film. Or both.
When Sn in the tin plating layer enters the film and reaches near the surface, the color tone of the film may be inferior. However, if the Ni—Sn alloy phase is precipitated in the film, the penetration of Sn is suppressed and the color tone is reduced. It becomes good. In addition, film adhesion and paint adhesion are also superior.

In addition, as a method for confirming the presence or absence of the Ni—Sn alloy phase in the film, for example, transmission electron microscope (TEM) electron diffraction or energy dispersive X-ray analysis (Energy dispersive X-ray spectrometry) And EDX), a point analysis or a line analysis method may be used for the surface or cross section of a sample produced by an extraction replica method or a focused ion beam (Focused Ion Beam; FIB) process.

[Manufacturing method and processing solution for steel plate for containers]
Although it does not specifically limit as a method to manufacture the steel plate for containers of this invention mentioned above, A plating steel plate is immersed in the processing liquid (henceforth "the processing liquid of this invention") mentioned later, or of this invention A method (hereinafter also referred to as “the production method of the present invention”) including at least a film forming step for forming the above-described film by performing cathodic electrolysis treatment on the plated steel sheet immersed in the treatment liquid is preferable.
Hereinafter, the production method of the present invention will be described, and in this description, the treatment liquid of the present invention will also be described.

[Film formation process]
The film forming step is a step of forming the above-described film on the surface of the plated steel sheet on the plating layer side, and immersing the plated steel sheet in the treatment liquid of the present invention described later (immersion process) or dipping. In this step, the steel sheet is subjected to cathodic electrolysis. Cathodic electrolytic treatment is preferable because a uniform film can be obtained at a higher speed than immersion treatment. In addition, you may implement the alternating electrolysis which performs a cathode electrolytic treatment and an anodic electrolytic treatment alternately.
Hereinafter, the treatment liquid of the present invention used, conditions for the cathodic electrolysis, and the like will be described in detail.

<Processing liquid>
The treatment liquid of the present invention contains a Ti component (Ti compound) for supplying Ti (titanium element) to the film.
The Ti component is not particularly limited. For example, titanium alkoxide, titanyl ammonium oxalate, potassium titanyl oxalate dihydrate, titanium sulfate, titanium lactate, titanium hydrofluoric acid (H ₂ TiF ₆ ) and / or its Examples include salt. Examples of the salt of titanium hydrofluoric acid include potassium hexafluorotitanate (K ₂ TiF ₆ ), sodium hexafluorotitanate (Na ₂ TiF ₆ ), and ammonium hexafluorotitanate ((NH ₄ ). ₂ TiF ₆ ) and the like.
Of these, titanium hydrofluoric acid and / or a salt thereof is preferable from the viewpoints of stability of the treatment liquid, availability, and the like.
The content of the Ti component in the treatment liquid of the present invention is not particularly limited, but when using titanium hydrofluoric acid and / or a salt thereof, the amount converted to hexafluorotitanate ion (TiF ₆ ²⁻ ), The amount is preferably 0.004 to 0.4 mol / L, more preferably 0.02 to 0.2 mol / L.

The treatment liquid of the present invention contains a Ni component (Ni compound) for supplying Ni (nickel element) to the coating.
As the Ni component is not particularly limited, nickel sulfate (NiSO _4), nickel sulfate hexahydrate, nickel chloride (NiCl _2), etc. nickel chloride hexahydrate and the like.
The content of the Ni component in the treatment liquid of the present invention is not particularly limited, but the amount converted to Ni ions (Ni ²⁺ ) is preferably 0.002 to 0.04 mol / L, preferably 0.004 to 0 0.02 mol / L is more preferable.

In addition, although water is normally used as a solvent in the processing liquid of this invention, you may use an organic solvent together.
The pH of the treatment liquid of the present invention is not particularly limited, but is preferably pH 2.0 to 5.0. Within this range, the treatment time can be shortened and the stability of the treatment liquid is excellent. A known acid component (for example, phosphoric acid, sulfuric acid) / alkali component (for example, sodium hydroxide, aqueous ammonia) can be used to adjust the pH.
Further, the treatment liquid of the present invention may contain a surfactant such as sodium lauryl sulfate or acetylene glycol as necessary. Further, from the viewpoint of the stability of the adhesion behavior over time, the treatment liquid may contain a condensed phosphate such as pyrophosphate.

Here, we return to the description of the film formation process. In the film formation step, the liquid temperature of the treatment liquid during the treatment is preferably 20 to 80 ° C., more preferably 40 to 60 ° C.

In the film formation step, the electrolysis current density at the time of carrying out the cathodic electrolysis treatment is 1.0 because Ti and Ni in the formed film are appropriate amounts, and the film adhesion and paint adhesion are more excellent. ˜20.0 A / dm ² is preferred, 3.0 to 15.0 A / dm ² is more preferred, and 6.0 to 10.0 A / dm ² is even more preferred.
At this time, the energization time of the cathodic electrolysis treatment is preferably 0.1 to 5 seconds and more preferably 0.3 to 2 seconds for the same reason.
The quantity of electricity at the time of cathodic electrolysis is the product of the current density and the energization time, and is appropriately set.

In addition, it is preferable to perform the water-washing process of the obtained steel plate after a cathodic electrolysis process for the reason of reducing F contained in a film | membrane.
The method of the water washing treatment is not particularly limited. For example, when the production is performed on a continuous line, a method of providing a water washing tank after the film treatment tank and continuously immersing in water after the film treatment is exemplified. The temperature of water used for the water washing treatment is preferably 40 to 90 ° C.
At this time, the washing time is preferably more than 0.5 seconds, and more preferably 1.0 to 5.0 seconds, because the effect of the washing treatment is more excellent.

Further, drying may be performed instead of or after the washing process. The temperature and method during drying are not particularly limited, and for example, a normal dryer or an electric furnace drying method can be applied. The temperature during the drying treatment is preferably 100 ° C. or lower. If it is in the said range, the oxidation of a film | membrane can be suppressed and stability of a film | membrane composition is maintained. The lower limit is not particularly limited, but is usually about room temperature.

The Ni—Sn alloy phase described above is formed in the film by subjecting the plated steel sheet having the tin plating layer to the film forming process described above using the treatment liquid of the present invention.

[Pretreatment process]
The manufacturing method of this invention may be equipped with the pre-processing process demonstrated below before the film formation process mentioned above.
The pretreatment step is a step of subjecting the plated steel plate to cathodic electrolysis in an alkaline aqueous solution (particularly, an aqueous sodium carbonate solution).
When the plating layer is a tin plating layer, the surface is usually oxidized during the production of the tin plating layer to form tin oxide. By subjecting the steel plate to cathodic electrolysis, unnecessary tin oxide can be removed and the amount of tin oxide can be adjusted.
Examples of the solution used for the cathodic electrolysis in the pretreatment step include an alkaline aqueous solution (for example, an aqueous sodium carbonate solution). The concentration of the alkali component (for example, sodium carbonate) in the alkaline aqueous solution is not particularly limited, but is preferably 5 to 15 g / L, more preferably 8 to 12 g / L from the viewpoint of more efficient removal of tin oxide. preferable.
The temperature of the alkaline aqueous solution during cathodic electrolysis is not particularly limited, but is preferably 40 to 60 ° C. The electrolysis conditions (current density, electrolysis time) of the cathodic electrolysis are appropriately adjusted. In addition, you may perform a water washing process after a cathode electrolytic process as needed.

The steel plate for containers of the present invention obtained by the manufacturing method of the present invention is used for manufacturing various containers such as DI cans, food cans and beverage cans.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

<Manufacture of plated steel sheets>
A plated steel sheet was produced by the following method.
First, a steel plate (T4 original plate) having a thickness of 0.22 mm is electrolytically degreased, and a nickel plating layer is formed on both sides with a Ni adhesion amount per one side shown in Table 3 using a Watt bath, and then 10 vol.% H ₂ +90 vol. An Fe—Ni alloy layer (Ni-containing layer) (showing Ni adhesion amount in Table 3) was formed on both sides by annealing at 700 ° C. in a .N ₂ atmosphere to diffuse and infiltrate the nickel plating.
Subsequently, a steel plate having a Ni-containing layer as the surface layer was formed using a tin plating bath, Sn layers were formed on both sides with the Sn adhesion amount per one side shown in Table 3, and a reflow treatment was performed at a melting point of Sn or higher. Tin plating layers were formed on both sides of the T4 original plate. In this way, a tin plating layer composed of Ni—Fe alloy layer / Fe—Sn—Ni alloy layer / Sn layer was formed in this order from the lower layer side.

<Film formation>
The plated steel sheet was immersed in an aqueous sodium carbonate solution having a bath temperature of 50 ° C. and 10 g / L, and cathodic electrolytic treatment was performed under the conditions shown in Table 2 (pretreatment step).
Next, the obtained steel sheet was washed with water, and the treatment liquid (solvent: water) having the composition shown in Table 1 with the pH adjusted to 4.0 was used, and the bath temperature (treatment temperature) and electrolysis conditions shown in Table 2 ( Cathodic electrolysis treatment was performed at current density, energization time, and electric density. Then, the obtained steel plate was washed with water, dried at room temperature using a blower, and a film was formed on both sides (film formation process). Thereby, the test material of the steel plate for containers was produced. The washing treatment was performed by immersing the obtained steel sheet in a water bath at 85 ° C. for the washing time shown in Table 3.

Then, the film adhesion was evaluated by the following method with respect to the test material of the produced steel plate for containers. The amount of each component and the evaluation results are summarized in Table 3.
Ti adhesion amount and Ni adhesion amount of film, Is (Ni), Is (Ti) and S, Ii (F), Ib (F) and T, film thickness, and Ni-Sn alloy phase in the film The presence or absence was measured or calculated by the method described above.

<Film adhesion>
As evaluation of film adhesiveness, the following non-processed film adhesiveness and post-processing film adhesiveness were evaluated.

《Unprocessed film adhesion》
A commercially available PET film (Melinex 850: manufactured by DuPont) is applied to the surface of the produced steel plate for containers under the conditions that the roll pressure is 4 kg / cm ² , the plate feed speed is 40 mpm, and the surface temperature of the plate after passing through the roll is 160 ° C. Then, heat-sealing was carried out, followed by post-heating in a batch furnace (holding at a final plate temperature of 210 ° C. for 120 seconds) to produce a laminated steel plate.
Evaluation of unprocessed film adhesion was performed by holding the produced laminated steel sheet in a retort atmosphere having a temperature of 130 ° C. and a relative humidity of 100% for 25 minutes, and then performing a 180 ° peel test in this retort atmosphere.
The 180 degree peel test uses a test piece (size: 30 mm × 100 mm) obtained by cutting a part 3 of the steel plate 1 while leaving the film 2 as shown in FIG. 1A, as shown in FIG. In addition, it is a film peeling test performed by attaching a weight 4 (100 g) to one end of the test piece, turning it 180 degrees to the film 2 side, and allowing it to stand for 30 minutes.
And the peeling length 5 shown in FIG.1 (c) was measured. The unprocessed film adhesion was evaluated according to the following criteria. If a result is (double-circle) or (circle), it can evaluate as what is excellent in unprocessed film adhesiveness.
A: Peel length is less than 1 mm B: Peel length is 1 mm or more and less than 5 mm Δ: Peel length is 5 mm or more and less than 10 mm ×: Peel length is 10 mm or more

<Film adhesion after processing>
A commercially available PET film (Melinex 850: manufactured by DuPont) is applied to the surface of the produced steel plate for containers under the conditions that the roll pressure is 4 kg / cm ² , the plate feed speed is 40 mpm, and the surface temperature of the plate after passing through the roll is 160 ° C. Then, heat-sealing was carried out, followed by post-heating in a batch furnace (holding at a final plate temperature of 210 ° C. for 120 seconds) to produce a laminated steel plate.
Using a punch with a tip diameter of 3/16 inch R, a 1 kg weight was dropped from a height of 25 cm, and DuPont impact processing was performed on the laminated steel plate thus produced so that the side on which the film was applied became convex. Four such processed test pieces are prepared, placed in the retort device so that the convex surface is on top, held for 30 minutes in a retort environment at 130 ° C., taken out, and visually checked the degree of film peeling of the processed part, Evaluation was made according to the following 5 levels. The film adhesion after processing was evaluated using the average value (one decimal place) of the four test pieces. Practically, if the result is 3.0 or more, it can be evaluated as having excellent film adhesion after processing.
5: No peeling 4: Peeling occurs when less than 5% of the area of the processed part 3: Peeling occurs when the area of the processed part is 5% or more and less than 20% 2: Peeling occurs when the area of the processed part is 20% or more and less than 50% 1 : Peeling occurs at 50% or more of the processed area

<Paint adhesion>
An epoxy phenol-based paint was applied to the surface of the produced steel plate for containers (width 100 mm × length 150 mm), and baked at 210 ° C. for 10 minutes to give a coating amount of 50 mg / dm ² . Next, after laminating the two coated steel plates prepared under the same conditions with the above coating so that the coated surfaces face each other across the nylon adhesive film, the pressure is 2.94 × 10 ⁵ Pa, Bonding was performed under pressure bonding conditions of a temperature of 190 ° C. and a pressure bonding time of 30 seconds. Then, this was divided into 5 mm wide test pieces. Two container steel plates of the divided test pieces were peeled off by a tensile tester, and the tensile strength when peeled off was measured. For each condition, the average value of the two divided test pieces was evaluated according to the following criteria. Practically, if the result is ○ or Δ, it can be evaluated as having excellent paint adhesion.
○: 2.0 kgf or more (equivalent to chromate treatment material)
Δ: 1.0 kgf or more and less than 2.0 kgf ×: less than 1.0 kgf

As is clear from the results shown in Tables 1 to 3 above, it was confirmed that all of the inventive examples were excellent in film adhesion and paint adhesion.
In all of the inventive examples, the S value is 1.00 or less. At this time, the inventive example in which the S value is less than 0.30 and the inventive example in which the S value is 0.30 or more and 1.00 or less. In contrast, the former was relatively better in paint adhesion than the latter, and the latter was better in film adhesion than the former.
In contrast, Comparative Example Ti coating weight of the coating is not less than 5.0 mg / m ² or more 60.0 mg / m ² or greater than Comparative Example S value is 1.00, the film adhesion and coating adhesion Was inferior.
Moreover, test material No. with T value exceeding 0.50. Compared with the inventive examples of Nos. 67 to 70, the test material No. The inventive examples 62 to 65 were more excellent in film adhesion.

DESCRIPTION OF SYMBOLS 1 Steel plate for containers 2 Film 3 Part cut out of steel plate 4 Weight 5 Stripping length

Claims

Plating having a plating layer composed of at least one layer selected from Ni layer, Sn layer, Ni—Fe alloy layer, Fe—Sn—Ni alloy layer and Fe—Sn alloy layer covering at least part of the surface of the steel plate A steel plate for containers having a steel plate and a coating disposed on the surface of the plated steel plate on the plating layer side,
The coating comprises Ti and Ni;
The mass ratio of Ni and Ti (Ni / Ti) of the coating is less than 1.0,
The coating, the deposition amount of Ti in terms of per side of coated steel sheet has a 5.0 mg / m 2 or more 60.0 mg / m of less than 2, the amount of deposition of Ni in terms of per side of the plated steel sheet is 3. The steel plate for containers which is 0 mg / m < 2 > and whose S value defined by following formula (1) is 1.00 or less.
S = [Is (Ni) / It (Ti)] (1)
(In the formula (1), Is (Ni) represents the amount of Ni (unit: mg / m 2 ) per one side of the plated steel sheet calculated from the glow discharge emission analysis of Ni from the surface of the coating to a depth of 10 nm. , It (Ti) represents the Ti amount (unit: mg / m 2 ) per one side of the plated steel sheet calculated from the glow discharge emission analysis of Ti of the entire coating.)
The steel sheet for containers according to claim 1, wherein the coating has an S value of less than 0.30.
The steel sheet for containers according to claim 1, wherein the coating has an S value of 0.30 or more and 1.00 or less.
The steel plate for containers according to any one of claims 1 to 3, wherein the coating has a Ti-equivalent adhesion amount of 10.0 to 30.0 mg / m 2 per one side of the plated steel plate.
The steel plate for containers according to any one of claims 1 to 4, wherein a T value defined by the following formula (2) is 0.50 or less.
T = [Ii (F) −Ib (F)] / Ib (F) (2)
(In Formula (2), Ii (F) represents the F peak count number of fluorescent X-ray analysis of the film, and Ib (F) represents the fluorescence of the film after the container steel plate was immersed in boiling water for 30 minutes. Represents the F peak count of X-ray analysis.)
The steel plate for containers according to any one of claims 1 to 5, wherein the plating layer is a tin plating layer, and the coating includes a Ni-Sn alloy phase.