JP6040716B2 - Treatment liquid, steel plate for container, and method for producing steel plate for container - Google Patents

Description

  The present invention relates to a treatment liquid used for producing a steel plate for containers, a steel plate for containers produced using this treatment liquid, and a method for producing a steel plate for containers using this treatment liquid.

As a steel plate for containers (surface-treated steel plate for cans), a tin-plated steel plate conventionally referred to as “blink” has been widely used. In such a tin-plated steel plate, the surface of the tin-plated surface is usually obtained by immersing the steel plate in an aqueous solution containing a hexavalent chromium compound such as dichromic acid, or by performing a chromate treatment such as performing an electrolytic treatment in this solution. A chromate film is formed on the surface.
However, in light of recent environmental problems, movements for restricting the use of Cr have progressed in various fields, and several treatment techniques for replacing chromate treatment have been proposed for steel plates for containers.
For example, Patent Document 1 states that “without using Cr and has excellent resin adhesion” ([0013]), “having a film containing Zr and O on at least one surface of a metal plate, A “surface-treated metal sheet” characterized in that the F amount is less than 0.1 mg / m ² per side ([Claim 1]), where “metal sheet” is “electrical Sn-plated steel sheet”. ([Claim 3]).

JP 2008-184630 A

In recent years, with the increasing demand for consumer aesthetics, further improvements have been required for various properties required for steel plates for containers.
The inventors further studied the steel plate for containers (surface-treated metal plate) disclosed in Patent Document 1. As a result, it was found that when a retort treatment was performed after laminating a resin such as a PET film, the adhesion to the film as the resin (hereinafter also referred to as “resin adhesion”) may be insufficient.
In addition, when the present inventors immerse the laminated steel plate in tomato juice under a predetermined condition, the resin film may be discolored, which is resistant to discoloration (hereinafter also referred to as “discoloration resistance”). I found it inferior. At this time, the present inventors have found that this discoloration is due to oxidation of tin (Sn) contained in the plating layer.

  This invention is made | formed in view of the above point, and it aims at providing the steel plate for containers excellent in resin adhesiveness and discoloration resistance.

  As a result of intensive studies to achieve the above object, the present inventors have formed a coating of a steel plate for containers using a treatment liquid containing a specific component, so that the resin adhesion and discoloration resistance are improved. They found that both were good and completed the present invention.

That is, the present invention provides the following (1) to (12).
(1) A steel plate with a tin plating layer having a tin plating layer covering at least a part of the surface of the steel plate and the steel plate, and a film disposed on the surface of the steel plate with the tin plating layer on the tin plating layer side. A treatment liquid for forming the coating film used for the production of a steel plate for containers, comprising a Zr compound, a Si compound, and a nitric acid compound, the Zr amount being 3-40 mmol / L, A treatment liquid, wherein the amount of Si is _{3 to 30} mmol / L, the amount of NO ₃ ⁻ is 10 to 100 mmol / L, and the amount of F is less than 0.1 mmol / L.
(2) The treatment liquid according to (1), wherein a part of the Zr compound and the nitric acid compound is zirconium oxynitrate, and the Si compound is colloidal silica.
(3) The above (1) or (3) further comprising a Ti compound and a lactic acid compound, wherein the Ti amount is 0.1 to 1 mmol / L and the lactic acid amount is 0.2 to 2 mmol / L. The processing liquid as described in 2).
(4) The treatment liquid according to (3), wherein the Ti compound and the lactic acid compound are titanium lactate.
(5) It has a steel plate with a tin plating layer which has a tin plating layer which covers at least one part of the surface of a steel plate and the above-mentioned steel plate, and a film arranged on the surface of the above-mentioned tin plating layer side steel plate of the above-mentioned tin plating layer It is a steel plate for containers, and the coating is formed using the treatment liquid described in (1) or (2) above, and the amount of adhesion in terms of Zr per side of the steel plate with the tin plating layer is 1.0 to 40.0 mg / m ^2, container steel sheet, wherein the adhered amount of Si in terms of per side of the tin-plated layer with the steel sheet is less than 1.0 mg / m ² or more 60.0 mg / m ^2.
(6) A steel plate with a tin plating layer having a tin plating layer covering at least a part of the surface of the steel plate and the steel plate, and a film disposed on the surface of the steel plate with the tin plating layer on the tin plating layer side. It is a steel plate for containers, and the coating is formed using the treatment liquid according to (3) or (4) above, and the amount of adhesion in terms of Zr per side of the steel plate with the tin plating layer is 1.0 to was 40.0 mg / m ^2, the adhesion amount of Si in terms of per side of the tin-plated layer with the steel sheet is less than 1.0 mg / m ² or more 60.0 mg / m ^2, one surface of the tin-plated layer with the steel sheet The steel plate for containers characterized by the adhesion amount of per Ti equivalent being 0.1-1.0 mg / m < ² >.
(7) Between the said steel plate with a tin plating layer and the said film | membrane, it has the phosphorus content layer whose adhesion amount of P conversion per single side of the said steel plate with a tin plating layer is 0.5-30.0 mg / m < ² >. The steel plate for containers as described in said (5) or (6).
(8) The steel plate for containers according to any of (5) to (7), wherein the steel plate with a tin plating layer is formed using a steel plate having a nickel-containing layer on the surface.
(9) A method for producing a container steel plate according to (5) above, wherein the steel sheet with a tin plating layer is immersed in the treatment liquid according to (1) or (2). Alternatively, a method for producing a steel plate for containers, wherein the film is formed by subjecting the immersed steel plate with a tin plating layer to cathodic electrolysis.
(10) A method for producing a container steel plate according to (6) above, wherein the steel sheet with a tin plating layer is immersed in the treatment liquid according to (3) or (4). Alternatively, a method for producing a steel plate for containers, wherein the film is formed by subjecting the immersed steel plate with a tin plating layer to cathodic electrolysis.
(11) A method for producing a container steel plate according to (7) above, wherein the steel plate with a tin plating layer is contained in a pretreatment liquid having a PO ₄ ^3- content of 70 to 800 mmol / L. In the treatment liquid according to any one of the above (1) to (4), after forming the phosphorus-containing layer by subjecting the steel plate with a tin plating layer to a cathode electrolysis treatment The film is formed by immersing the steel sheet with the tin plating layer on which the phosphorus-containing layer is formed, or by subjecting the steel sheet with the tin plating layer on which the immersed phosphorus-containing layer is formed to cathodic electrolysis. The manufacturing method of the steel plate for containers characterized by performing.
(12) The method for manufacturing a steel plate for containers according to any one of (9) to (11), wherein the steel plate with a tin plating layer is formed using a steel plate having a nickel-containing layer on the surface.

  ADVANTAGE OF THE INVENTION According to this invention, the steel plate for containers excellent in resin adhesiveness and discoloration resistance can be provided.

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

[Steel plate for containers]
The steel plate for containers according to the present invention has a steel plate with a tin plating layer and a film disposed on the surface of the steel plate with a tin plating layer on the tin plating layer side. By using it, it is excellent in resin adhesiveness and discoloration resistance.
Below, the steel plate with a tin plating layer and the specific aspect of a membrane | film | coat are explained in full detail. First, the aspect of the steel plate with a tin plating layer is explained in full detail.

<Steel-coated steel sheet>
The steel sheet with a tin plating layer has a tin plating layer that covers at least a part of the surface of the steel sheet and the steel sheet. Below, the aspect of a steel plate and a tin plating layer is explained in full detail.

(steel sheet)
The type of the steel plate in the steel plate with the tin plating layer 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 restricted, and the steel plate is manufactured through processes such as hot rolling, pickling, cold rolling, annealing, and temper rolling from a normal steel 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 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 and a Ni—Fe alloy layer.
The method for applying the Ni-containing layer to the steel plate is not particularly limited, and examples thereof include known methods such as electroplating. Also, when a Ni-Fe alloy layer is applied as the Ni-containing layer, the Ni diffusion layer is coordinated to form a Ni-Fe alloy layer by annealing after applying Ni on the steel sheet surface by electroplating or the like. Can do.
The amount of Ni in the Ni-containing layer is not particularly limited, and is preferably 50 to 2000 mg / m ² as metal Ni equivalent per one 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.

(Tin plating layer)
The steel plate with a tin plating layer has a tin plating layer on the steel plate surface. 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. Especially, 0.2-15.0 g / m < ² > is preferable at the point which these characteristics are more excellent, and 1.0-15.0 g / m < ² > is further more preferable at the point which processability is more excellent.

  Note that the Sn adhesion amount can be measured by surface analysis using a coulometric method or fluorescent X-ray. In the case of fluorescent X-rays, a calibration curve relating to the amount of metallic Sn is specified in advance using an Sn adhesion amount sample with a known amount of metallic Sn, and the amount of metallic Sn 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, a tin plating layer obtained by plating tin, or by heating and melting tin by energization heating after tin plating, the Fe-Sn alloy layer at the tin plating bottom layer (tin plating / base metal interface) Includes a tin plating layer partially formed.
In addition, as a tin plating layer, tin plating is performed on a steel sheet having a Ni-containing layer on the surface, and tin is further heated and melted by energization heating or the like, and Fe-- is added to the tin plating bottom layer (tin plating / base metal interface). It also includes a tin plating layer in which a part of Sn—Ni alloy, Fe—Sn alloy layer or the like is formed.

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 sulfonate tin plating bath, a methane sulfonate tin plating bath, or a halogen-based tin plating bath is used, and Sn is applied to the surface of the steel sheet so that the adhesion amount per side becomes a predetermined amount (for example, 2.8 g / m ² ). After electroplating, a reflow process is performed at a temperature equal to or higher than the melting point of Sn (231.9 ° C.), and a tin plating layer in which an Fe—Sn alloy layer is formed in the lowermost layer of the tin plating layer can be manufactured. When the reflow process is omitted, a tin plating layer can be produced.

  Also, when the steel sheet has a Ni-containing layer on its surface, a tin plating layer is formed on the Ni-containing layer and reflow treatment is performed. -Sn-Ni alloy layer, Fe-Sn alloy layer, etc. are formed.

<Film>
A film | membrane is arrange | positioned on the surface by the side of the tin plating layer of the steel plate with a tin plating layer mentioned above.
The coating contains Zr (zirconium element) and Si (silicon element) as its components. Further, the coating has a Zr equivalent adhesion amount (hereinafter also referred to as “Zr adhesion amount”) of 1.0 to 40.0 mg / m ² per one side of the steel sheet with the tin plating layer, adhesion amount of Si in terms of per side (hereinafter, also referred to as "Si deposition amount") is less than 1.0 mg / m ² or more 60.0 mg / m ^2.
The Zr adhesion amount is preferably 5.0 to 25.0 mg / m ² , and more preferably 9.0 to 22.0 mg / m ² , because the resin adhesion and discoloration resistance are more excellent.
10-40 mg / m < ² > is preferable and 15-30 mg / m < ² > is more preferable from the reason that the said resin adhesion is more excellent.

  Here, the mass ratio (Si / Zr) between Si and Zr of the film is preferably 0.10 or more and less than 2.00, because the resin adhesion and discoloration resistance are more excellent, and 0.60 to 1 .50 is preferable, and 0.75 to 1.00 is more preferable.

The film may further contain Ti (titanium element). When the film contains Ti in combination with Si, the effect of resin adhesion due to the action of Si is further improved. At this time, the adhesion amount in terms of Ti per one side of the steel plate with the tin plating layer (hereinafter also referred to as “Ti adhesion amount”) is, for example, 0.1 to 1.0 mg / m ² , and the above effect is further excellent. Therefore, 0.7 to 1.0 mg / m ² is preferable, and 0.5 to 1.0 mg / m ² is more preferable.

In addition, the coating film has an F-attached amount (hereinafter also referred to as “F-attached amount”) per one side of the steel plate with a tin plating layer, because of better resin adhesion and discoloration resistance. preferably less than .2mg / m ^2, more preferably less than 0.1 mg / m ^2, more preferably less than 0.07 mg / m ^2, less than 0.05 mg / m ² is particularly preferred, coating F (fluorine An embodiment which does not substantially contain (element) is most preferable.

The above-described Zr adhesion amount, Si adhesion amount, and Ti adhesion amount can be measured by surface analysis using fluorescent X-rays.
The F adhesion amount can be calculated based on the Zr adhesion amount measured by the surface analysis using the fluorescent X-ray by measuring the atomic ratio of Zr and F on the outermost surface of the film by XPS analysis.

  In addition, Zr, Si, Ti, etc. in a film | membrane are each contained as various zirconium compounds, a silicon compound, and a titanium compound, and the kind and aspect of these compounds are not specifically limited.

In the case where a lactic acid compound such as titanium lactate [Ti (OH) ₂ [OCH (CH ₃ ) COOH] ₂ ] is contained in the treatment liquid of the present invention described later, in the infrared absorption (IR) spectrum of the film, It is considered that an absorption peak derived from the secondary hydroxy group (CH—OH) is shown in the range of wave numbers from 1050 to 1150 cm ⁻¹ , that is, the secondary hydroxy group is included in the film.

Examples of the measurement conditions of the infrared absorption (IR) spectrum include the following.
Apparatus: FTS-3100 manufactured by Varian
Measuring method: ATR / GE prism Resolution: 4 cm ^-1
Integration count: 32 times

<Phosphorus-containing layer>
The container steel plate of the present invention preferably has a phosphorus-containing layer containing P (phosphorus element) between the above-described steel plate with a tin plating layer and the above-described coating. Specifically, it has a phosphorus-containing layer in which the adhesion amount in terms of P (hereinafter also referred to as “P adhesion amount”) per one side of the steel plate with a tin plating layer is 0.5 to 30.0 mg / m ² . Is preferred.
By having such a phosphorus-containing layer, oxidation of the tin plating layer in the steel plate for containers of the present invention is suppressed, and discoloration resistance is further improved. Moreover, although the layer containing phosphorus may be inferior in the adhesiveness with respect to resin, such as PET film, in this invention, since the phosphorus containing layer is covered with the membrane | film | coat mentioned above, resin adhesiveness is also favorable.
And since the discoloration resistance of the steel plate for containers of the present invention is further excellent, the P adhesion amount of the phosphorus-containing layer is preferably 1.0 to 10.0 mg / m ² , and 2.0 to 5.0 mg / m 2. ² is more preferable. Note that the P adhesion amount can be measured by surface analysis using fluorescent X-rays.

[Manufacturing method and processing solution for steel plate for containers]
As a method for producing the above-described steel plate for containers of the present invention, a steel plate with a tin plating layer is immersed in the processing solution of the present invention described later, or a steel plate with a tin plating layer immersed in the processing solution of the present invention. It is preferable that the method includes at least a film forming step for forming the above-described film by performing a cathodic electrolysis treatment (hereinafter also referred to as “production method of the present invention”).
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 on the tin plating layer side of the steel plate with the tin plating layer, and immersing the steel plate with the tin plating layer in the treatment liquid of the present invention described later (immersion) Treatment), or a step of subjecting the immersed steel plate 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 of the present invention)
The treatment liquid of the present invention generally contains a Zr compound as a Zr supply source for supplying Zr to the coating, and contains a Si compound as a Si supply source for supplying Si to the coating. The steel plate for containers of the present invention is excellent in resin adhesion and discoloration resistance by forming a film using the treatment liquid of the present invention.
Although the mechanism by which the above effect is obtained is not clear, the Si compound deposited in the film has a large specific surface area and a needle-like shape, and the adhesion between the resin (film) and the film due to the anchor effect of this compound The formation of a composite compound with Zr in the film suppresses the oxidation of Sn in the tin plating layer by suppressing the diffusion of moisture at a high temperature at the interface between the resin and the film. The reason is that the effect is synergistically improved.
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.

  For the Zr compound contained in the treatment liquid of the present invention, the amount converted to Zr (also referred to as “Zr amount”) is 3 to 40 mmol / L. When the amount of Zr is less than 3 mmol / L, it is difficult to ensure the amount of Zr adhesion for ensuring resin adhesion in the formed film. On the other hand, when the amount of Zr exceeds 40 mmol / L, the effect is saturated, which is not preferable from the viewpoint of cost. However, if the amount of Zr is 3 to 40 mmol / L, the resin adhesion is excellent. For the reason that this effect is more excellent, the amount of Zr is preferably 5 to 30 mmol / L, and more preferably 10 to 20 mmol / L.

The Zr compound contained in the treatment liquid of the present invention is preferably zirconium oxynitrate because precipitation does not occur with respect to the pH fluctuation of the treatment liquid and it is stable. Zirconium oxynitrate [ZrO (NO ₃ ) ₂ ] is also called zirconyl nitrate. When the treatment liquid of the present invention contains zirconium oxynitrate, a fluorine-based zirconium supply source such as zircon potassium fluoride is not used, and the F adhesion amount of the film is reduced.

  About the Si compound which the processing liquid of this invention contains, the quantity converted to Si (it is also called "Si quantity") is 3-30 mmol / L. When the amount of Si is less than 3 mmol / L, it is difficult to secure the amount of Si adhesion for ensuring resin adhesion in the formed film. On the other hand, when the amount of Si exceeds 30 mmol / L, discoloration resistance is inferior. However, if the amount of Si is 3 to 30 mmol / L, the resin adhesion and the discoloration resistance are excellent. From the reason that this effect is more excellent, the amount of Si is preferably 5 to 20 mmol / L.

The Si compound contained in the treatment liquid of the present invention is preferably colloidal silica because it is excellent in stability of the treatment liquid and film formability. Colloidal silica is a dispersion in water whose basic unit is SiO ₂ . The amount of moisture is not particularly limited, but usually contains 20 to 30% by mass of SiO ₂ as a solid content in colloidal silica.
Although the average particle diameter of the colloidal silica used for this invention is not specifically limited, 30 nm or less is preferable, 20 nm or less is more preferable, and 10 nm or less is further more preferable. When the average particle diameter of the colloidal silica is within this range, the specific surface area of the Si compound precipitated in the film becomes larger and the resin adhesion is more excellent.
On the other hand, the lower limit of the average particle diameter of colloidal silica is not particularly limited, and is preferably 1 nm or more, for example.
In addition, an average particle diameter can be measured by BET method (converted from the specific surface area by an adsorption method). It is also possible to substitute an average value actually measured from an electron micrograph.
As such colloidal silica, commercially available products can be used, and specifically, for example, SNOWTEX O (average particle size: 10 to 20 nm), SNOWTEX OXS (average particle size: manufactured by Nissan Chemical Industries, Ltd.). 4 to 6 nm), Snowtex OS (average particle size: 8 to 11 nm), PL-2L (average particle size: 15 to 20 nm) manufactured by Fuso Chemical Industries, and the like.

Furthermore, the treatment liquid of the present invention contains a nitric acid compound, and the amount converted to nitrate ion (NO ₃ ⁻ ) (also referred to as “NO ₃ ⁻ amount”) is 10 to 100 mmol / L. When the amount of NO ₃ ⁻ is less than 10 mmol / L, it is difficult to ensure conductivity in the treatment liquid, and high-speed operability is deteriorated. On the other hand, NO ₃ ^- the amount exceeds 100 mmol / L, in the film formed, ensuring Zr coating weight and Ti deposition amount for ensuring resin adhesion becomes difficult. However, when the amount of NO ₃ ⁻ is 10 to 100 mmol / L, the high-speed operability and the resin adhesion are excellent. For the reason that this effect is more excellent, the NO ₃ ⁻ amount is preferably 20 to 80 mmol / L, more preferably 20 to 50 mmol / L.

The nitrate compound contained in the treatment liquid of the present invention is not particularly limited as long as it provides nitrate ions (NO ₃ ⁻ ), and examples thereof include nitrates such as potassium nitrate, ammonium nitrate, and sodium nitrate. One species may be used alone, or two or more species may be used in combination. Of these, potassium nitrate and ammonium nitrate are preferred because of the excellent stability of the treatment liquid.
Moreover, the treatment liquid of the present invention may contain zirconium oxynitrate as the Zr compound in addition to these nitrates as the nitrate compound. That is, in the treatment liquid of the present invention, the Zr compound may also serve as the nitric acid compound.

  Further, in the treatment liquid of the present invention, the amount of F compound converted to F (also referred to as “F amount”) is less than 0.1 mmol / L from the viewpoint of reducing the F adhesion amount of the formed film. Less than .05 mmol / L is preferred, and an embodiment containing substantially no F compound is particularly preferred.

  The treatment liquid of the present invention may further contain a Ti compound as a Ti supply source for supplying Ti to the film, and the amount converted to Ti (also referred to as “Ti amount”) is 0.1 to 0.1. 1 mmol / L is preferred. If the amount of Ti is less than 0.1 mmol / L, it may be difficult to ensure the amount of Ti adhered to ensure resin adhesion in the formed film. On the other hand, when the amount of Ti exceeds 1 mmol / L, discoloration resistance may deteriorate. However, if the amount of Ti is 0.1 to 1 mmol / L, the resin adhesion and the discoloration resistance are more excellent. From the reason that these effects are further excellent, the Ti amount is preferably 0.2 to 0.8 mmol / L.

Examples of the Ti compound contained in the treatment liquid of the present invention include titanium lactate, titanium hydrofluoric acid, potassium hexafluorotitanate, titanyl potassium oxalate, and titanium sulfate. Titanium lactate is preferred because it is easy to secure the amount of Ti adhesion for ensuring adhesion. Titanium lactate [Ti (OH) ₂ [OCH (CH ₃ ) COOH] ₂ ] is also called dihydroxybis (lactato) titanium, and in the present invention, it includes its ammonium salt (monoammonium salt, diammonium salt). .
When the treatment liquid of the present invention contains such titanium lactate, it is considered that the formed film has secondary hydroxy groups (CH—OH). Further, since a fluorine-based titanium supply source such as titanium hydrofluoric acid is not used, the F adhesion amount of the film is reduced.

The treatment liquid of the present invention may contain a lactic acid compound, and the amount (also referred to as “lactic acid amount”) converted to lactic acid (CH ₃ CH (OH) COOH) is 0.2 to 2 mmol / L. Is preferred. If the amount of lactic acid is less than 0.2 mmol / L, the resin adhesion may deteriorate in the formed film. On the other hand, when the amount of lactic acid exceeds 2 mmol / L, the effect is saturated and it may not be preferable from the viewpoint of cost. However, if the amount of lactic acid is 0.2 to 2 mmol / L, the resin adhesion is more excellent. For the reason that this effect is further excellent, the amount of lactic acid is preferably 0.4 to 1.6 mmol / L.

  The lactic acid compound contained in the treatment liquid of the present invention is not particularly limited, and examples thereof include lactic acid and conventionally known lactate salts, lactic acid esters, lactic acid chelates and the like. As the compound, titanium lactate as the Ti compound can be contained. That is, in the treatment liquid of the present invention, the lactic acid compound may also serve as the Ti compound (or the Ti compound may also serve as the lactic acid compound).

  In addition, although water is normally used as a solvent in the processing liquid of this invention, you may use an organic solvent together.

Although the pH of the processing liquid of this invention is not specifically limited, pH 2.0-5.0 are preferable. Within this range, the treatment time can be shortened and the stability of the treatment liquid is excellent.
For adjusting the pH, known acid components (for example, phosphoric acid, sulfuric acid, nitric acid) / alkali components (for example, sodium hydroxide, potassium hydroxide, aqueous ammonia) can be used.

  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.

  Returning to the description of the film forming process again. In the film forming step, the liquid temperature of the treatment liquid at the time of performing the treatment is preferably 20 to 80 ° C., and preferably 40 to 60 ° C. from the viewpoint of film formation efficiency and tissue uniformity and low cost. More preferred.

In the film formation step, the electrolysis current density at the time of carrying out the cathodic electrolysis treatment is preferably a low current density from the reason that the resin adhesion and discoloration resistance of the film to be formed are more excellent. is preferably ^{0.05~7.0A / dm 2, 0.5~5.0A / dm} 2 is more preferable. By using the treatment liquid of the present invention, a film can be formed at a low current density.

  At this time, the energization time of the cathodic electrolysis treatment is 0.1 to 5 seconds from the point that the decrease in the adhesion amount is further suppressed and the film can be stably formed, and the characteristic deterioration of the formed film is further suppressed. Preferably, 0.3 to 2 seconds is more preferable.

In addition, in order to remove an unreacted substance after a cathode electrolytic treatment, you may perform the water-washing process and / or drying of the obtained steel plate as needed. In addition, it does not specifically limit about the temperature and system in the case of drying, For example, a normal dryer and an electric furnace drying system are applicable.
In addition, as temperature in the case of a drying process, 100 degrees C or less is preferable. 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.

<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 steel plate with the tin plating layer to cathodic electrolysis in an alkaline aqueous solution (particularly, an aqueous sodium carbonate solution).
Usually, the surface of the tin-plated layer is oxidized 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 alkaline 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 that removal of tin oxide proceeds more efficiently. preferable.
The temperature of the alkaline aqueous solution during the 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.

Moreover, the pretreatment process with which the manufacturing method of this invention is provided is not limited to the said process, For example, the steel plate with a tin plating layer is immersed in the solution containing a phosphorus supply source, or the steel plate with the tin plating layer which was immersed It may be a step of performing cathodic electrolysis treatment.
By passing through such a pretreatment process, the phosphorus-containing layer described above is formed on the surface on the tin plating layer side of the steel plate with the tin plating layer. Then, the steel plate with a tin plating layer in which the phosphorus-containing layer is formed undergoes the above-described film formation step, whereby a film is formed.

Here, as a P supply source contained in a solution used in the pretreatment step for forming the phosphorus-containing layer (hereinafter also referred to as “pretreatment liquid of the present invention”), phosphate ions (PO ₄ ³⁻ ) are used. It will not specifically limit if it is a P compound to give, For example, phosphoric acid (orthophosphoric acid), aluminum phosphate, calcium phosphate, magnesium phosphate, phosphoric acid, such as manganese phosphate, and / or its salt are mentioned.
For the P compound in the pretreatment liquid of the present invention, the amount converted to phosphate ion (PO ₄ ³⁻ ) (also referred to as “PO ₄ ³⁻ amount”) is preferably 70 to 800 mmol / L. When the amount of PO ₄ ³⁻ is less than 70 mmol / L, it may be difficult to ensure the P adhesion amount for ensuring discoloration resistance in the formed phosphorus-containing layer. On the other hand, when the amount of PO ₄ ³⁻ exceeds 800 mmol / L, the effect of discoloration resistance is saturated, which may not be preferable from the viewpoint of cost. However, if the amount of PO ₄ ^3- is 70 to 800 mmol / L, the discoloration resistance is more excellent, and this effect is further excellent, so that 100 to 500 mmol / L is more preferable, and 200 to 400 mmol / L is more preferable. .

In the pretreatment step of forming the phosphorus-containing layer using the pretreatment liquid of the present invention, the liquid temperature during immersion or cathodic electrolysis is not particularly limited, but is preferably 40 to 60 ° C. Moreover, although the electrolysis conditions for the cathodic electrolysis are appropriately adjusted, for example, the electrolysis current density during the cathodic electrolysis is 0.05 to 15.0 A / dm from the reason that a desired phosphorus adhesion amount is obtained. ² is preferable, and 1.0 to 12.0 A / dm ² is more preferable.
At this time, the energization time of the cathodic electrolysis treatment is not particularly limited, but is preferably 0.1 to 10.0 seconds, and more preferably 0.3 to 7.0 seconds.
In order to obtain a desired phosphorus adhesion amount in a short time, it is preferable to perform cathodic electrolysis.
In addition, you may perform a water washing process after immersion or a cathodic electrolysis 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 steel sheet with tin plating layer>
A steel plate with a tin plating layer was produced by the following two methods [(K-1) and (K-2)].
(K-1)
Electrolytic degreasing and pickling were performed on a steel plate (T4 original plate) having a thickness of 0.22 mm, and then tin plating was performed. Subsequently, it was heated and melted at a temperature equal to or higher than the melting point of tin, and a tin plating layer having an Sn adhesion amount per one side shown in Table 4 was formed on both sides of the T4 original plate.
(K-2)
A steel plate (T4 original plate) having a thickness of 0.22 mm was electrolytically degreased, and a nickel plating layer was formed on both sides with a Ni adhesion amount per one side shown in Table 4 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 4) was formed on both sides by annealing at 700 ° C. in an N ₂ atmosphere to diffuse and infiltrate nickel plating.
Subsequently, a steel plate having a Ni-containing layer on the surface layer was formed using a tin plating bath, a Sn layer was formed on both sides with the Sn adhesion amount per one side shown in Table 4, 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.

<Formation of film>
A steel sheet with a tin plating layer was immersed in a pretreatment liquid (solvent: water) having the composition shown in Table 1 and subjected to cathodic electrolysis under the conditions shown in Table 3 to form a phosphorus-containing layer (previous Processing step).
Thereafter, the obtained steel sheet was washed with water, and the treatment liquid (solvent: water) having the composition shown in Table 2 with the pH adjusted to 2.4 was used, and the bath temperature and electrolysis conditions (current density, energization) shown in Table 3 Time). 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).

The produced steel sheet was evaluated for resin adhesion and discoloration resistance by the following methods. Table 4 summarizes the amount of each component and the evaluation results.
The P adhesion amount of the phosphorus-containing layer, the Zr adhesion amount, the Si adhesion amount, the Ti adhesion amount, and the F adhesion amount of the film were measured by the above-described methods.

<Resin adhesion>
A laminated steel plate was prepared by laminating an isophthalic acid copolymerized polyethylene terephthalate film having a thickness of 25 μm and a copolymerization ratio of 12 mol% on both surfaces of the produced steel plate for containers. Lamination was performed by sandwiching a steel plate and a film heated to 210 ° C. between a pair of rubber rolls, fusing the film to the steel plate, and cooling with water within 1 sec after passing through the rubber roll. At this time, the feeding speed of the steel plate was 40 m / min, and the nip length of the rubber roll was 17 mm. Here, the nip length is the length in the transport direction of the portion where the rubber roll and the steel plate are in contact. And about the produced laminated steel plate, the following resin adhesiveness evaluation was performed.
Evaluation of resin adhesion was performed by a 180 ° peel test in a retort atmosphere at a temperature of 150 ° C. and a relative humidity of 100%. The 180 ° 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, a film peeling test is performed by attaching a weight 4 (100 g) to one end of the test piece, turning it 180 ° 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, resin adhesiveness was evaluated as follows, and if it was (double-circle) or (circle), it was considered that resin adhesiveness was favorable.
A: Peel length is less than 10 mm B: Peel length is 10 mm or more and less than 15 mm Δ: Peel length is 15 mm or more and less than 50 mm X: Peel length is 50 mm or more

<Discoloration resistance>
Lamination was performed on both surfaces of the produced steel plate for containers in the same manner as when the resin adhesion was evaluated to produce a laminated steel plate. A test piece (size: 50 mm × 100 mm) of a laminated steel plate was placed in a beaker containing a commercially available tomato juice, and a test was performed in a constant temperature bath at 55 ° C. for 20 days. Discoloration of the gas phase part (part not immersed in tomato juice) was evaluated.
The L value, a value, and b value of the laminated steel sheet before and after the test were measured with a color meter SM-T manufactured by Suga Test Instruments, and the color difference before and after the test was calculated as follows.
ΔE = ((before L test−after L test) ² + (before a test−after a test) ² + (before b test−after b test) ² ) ^0.5
As a result, the discoloration resistance was evaluated as follows, and if it was A or B, it was determined that the discoloration resistance was good.
◎: Color difference is less than 2 ○: Color difference is 2 or more, less than 7 Δ: Color difference is 7 or more, less than 15 ×: Color difference is 15 or more

As is clear from the results shown in Tables 1 to 4 above, it was confirmed that all of the inventive examples were excellent in resin adhesion and discoloration resistance.
On the other hand, Comparative Examples 1-16 were inferior in resin adhesiveness and discoloration resistance.
In particular, Comparative Examples 1, 2, 12 and 13 using the treatment liquid B22 or B23 having an Si amount of 0 mmol / L were particularly inferior in resin adhesion. In Comparative Example 14 using the treatment liquid B28 having an Si amount of less than 3 mmol / L, the resin adhesion was not good.
Further, Comparative Examples 3, 4, 7, 10 and 11 using the treatment liquid B24 or B25 having a Zr amount of less than 3 mmol / L were particularly inferior in resin adhesion.
Further, Comparative Examples 5, 6, 8 and 9 using the treatment liquid B26 or B27 having an NO ₃ ⁻ amount exceeding 100 mmol / L were also particularly inferior in resin adhesion.
Further, Comparative Example 15 using the treatment liquid B29 having an Si amount exceeding 30 mmol / L was particularly inferior in discoloration resistance.
Furthermore, Comparative Example 16 using the treatment liquid B31 having an F amount exceeding 0.1 mmol / L was inferior in both resin adhesion and discoloration resistance.

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

Claims (11)

A steel plate for a container comprising a steel plate and a steel plate with a tin plating layer having a tin plating layer covering at least a part of the surface of the steel plate, and a coating disposed on the surface of the steel plate with the tin plating layer on the tin plating layer side A treatment liquid for forming the film,
Containing a Zr compound, a Si compound, and a nitric acid compound,
The amount of Zr is 3 to 40 mmol / L,
Si amount is 3-30 mmol / L,
NO ₃ ^- amount is 10-100 mmol / L,
F amount of state, and are less than 0.1mmol / L,
The Zr compound and a part of the nitric acid compound are zirconium oxynitrate,
A treatment liquid , wherein the Si compound is colloidal silica . Furthermore, it contains a Ti compound and a lactic acid compound,
Ti amount is 0.1-1 mmol / L,
The processing liquid according to claim 1, wherein the amount of lactic acid is 0.2 to 2 mmol / L. The treatment liquid according to claim 2 , wherein the Ti compound and the lactic acid compound are titanium lactate. A steel plate for a container comprising a steel plate and a steel plate with a tin plating layer having a tin plating layer covering at least a part of the surface of the steel plate, and a coating disposed on the surface of the steel plate with the tin plating layer on the tin plating layer side Because
The coating is formed using the treatment liquid according to claim 1, and the amount of adhesion in terms of Zr per side of the steel plate with the tin plating layer is 1.0 to 40.0 mg / m ² , and the tin plating container steel sheet for adhesion amount of Si in terms of per side layer with the steel sheet is equal to or less than 1.0 mg / m ² or more 60.0 mg / m ^2. A steel plate for a container comprising a steel plate and a steel plate with a tin plating layer having a tin plating layer covering at least a part of the surface of the steel plate, and a coating disposed on the surface of the steel plate with the tin plating layer on the tin plating layer side Because
The coating is formed by using the treatment liquid according to claim 2 or 3 , wherein a Zr-converted adhesion amount per side of the steel sheet with the tin plating layer is 1.0 to 40.0 mg / m ² , adhesion amount of Si in terms of per side of the tin-plated layer with the steel sheet is less than 1.0 mg / m ² or more 60.0 mg / m ^2, the adhesion amount of Ti in terms of per side of the tin-plated layer with the steel sheet is 0. The steel plate for containers characterized by being 1 to 1.0 mg / m ² . Between the said steel plate with a tin plating layer and the said film | membrane, it has a phosphorus content layer whose adhesion amount of P conversion per one side of the said steel plate with a tin plating layer is 0.5-30.0 mg / m < ² >. The steel plate for containers according to 4 or 5 . The steel plate for containers according to any one of claims 4 to 6 , wherein the steel plate with a tin plating layer is formed using a steel plate having a nickel-containing layer on the surface. It is a manufacturing method of the steel plate for containers which obtains the steel plate for containers according to claim 4 ,
The said coating film is formed by immersing the said steel plate with a tin plating layer in the processing liquid of Claim 1 , or performing a cathodic electrolysis process to the immersed said steel plate with a tin plating layer, The container characterized by the above-mentioned. Steel plate manufacturing method. It is a manufacturing method of the steel plate for containers which obtains the steel plate for containers according to claim 5 ,
The said coating is formed by immersing the said steel plate with a tin plating layer in the processing liquid of Claim 2 or 3 , or performing a cathodic electrolysis process to the immersed said steel plate with a tin plating layer, It is characterized by the above-mentioned. A method for manufacturing a steel sheet for containers. It is a manufacturing method of the steel plate for containers which obtains the steel plate for containers according to claim 6 ,
By immersing the steel sheet with a tin plating layer in a pretreatment solution having a PO ₄ ^3- amount of 70 to 800 mmol / L, or by subjecting the immersed steel sheet with a tin plating layer to cathodic electrolytic treatment, After the layer is formed, the steel sheet with the tin plating layer on which the phosphorus-containing layer is formed is immersed in the treatment liquid according to any one of claims 1 to 3 , or the phosphorus-containing layer is immersed in the processing solution. The said coating film is formed by performing the cathodic electrolysis process on the said steel plate with a tin plating layer in which this was formed, The manufacturing method of the steel plate for containers characterized by the above-mentioned. The tin-plated layer with the steel sheet was formed by using a steel sheet having a nickel-containing layer on the surface, method of manufacturing containers for steel sheet according to any one of claims 8-10.

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