JP2711947B2 - Method for producing resin-coated tin-plated steel sheet for thinned deep drawn cans with excellent processing corrosion resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin-coated tin-plated steel sheet for a thin-walled deep drawn can excellent in processing corrosion resistance. More specifically, tin-plated steel sheet or after tin plating,
A small amount of nickel-plated steel sheet is heated to a temperature higher than the melting point of tin in a non-contact state, and a thermoplastic resin film or a thermoplastic resin film coated with a specific polymer is immediately pressed on both sides. The present invention relates to a method for producing a resin-coated tin-coated steel sheet for a thin-walled deep drawn can having excellent corrosion resistance, which is laminated and quenched simultaneously to a temperature equal to or lower than the melting point of tin.

[0002]

2. Description of the Related Art Conventionally, a food or beverage can has a three-piece can consisting of a can body, a can lid, and a bottom lid, a can body in which the can body and the bottom lid are integrated, and a can body and a can lid. A two-piece two-piece can is used. The tin body of the three-piece can is painted once or several times, and is made of electrolytic chromic acid-treated steel plate (generally called tin-free steel, hereinafter abbreviated as TFS). Attached
A method of bonding with nylon or resistance welding is used. Applying the coating in this manner not only complicates the baking process, but also requires long-time heating for baking. Further, since a large amount of solvent components in the paint are discharged in the baking step, there is a drawback that the discharged solvent must be led to a special incinerator and incinerated from the viewpoint of pollution. For two-piece cans, drawn cans, drawn redrawn cans (Dr
awn and redrawncan, DRD can),
Draw and Ironed C (Drawn and Ironed C
an, DI can), but for tins with a relatively small drawing ratio such as drawn cans and DRD cans, painted tin or TFS is used in the same manner as the above-mentioned three-piece can material. . Therefore, there is a problem in terms of process and environmental pollution as in the above. In addition, tin and aluminum are used for DI cans, but lubricating oil is used for the production of DI cans at the time of molding. After molding, the lubricating oil is removed by washing, and after drying, the inner and outer surfaces of the cans are removed. Is painted. Also in the manufacturing process of this DI can, there are problems in terms of pollution, such as treatment of lubricating oil and treatment of a solvent component volatilized from paint during baking of paint. In recent years, a technique for manufacturing a thinned deep drawn can that is stretched after drawing has been developed, and painted TFS has been studied as a material for the thinned deep drawn can. However, painted TFS
When such severe processing is performed, the coating film has numerous cracks and cannot be used for highly corrosive contents. Compared to DI can manufacturing technology, this thin-walled deep-drawing can manufacturing technology is, for example, a pre-coated material that has a compact manufacturing equipment, low equipment costs, a small area required for equipment installation, and a reduction in the number of operating personnel. Although it has many advantages, such as the possibility of use, it is not widely used because there is no material having excellent corrosion resistance.

Recently, instead of coating, a method of using a metal plate obtained by laminating a thermoplastic resin film such as a polyester resin film on TFS, tinplate, etc., for a thinned deep drawing can (JP-A-2-269647, JP-A-2-26947) No. 263523)
Has been proposed. When the TFS laminated with a polyester resin film is used for a thinned drawing can, the laminated polyester resin film may be peeled off by severe processing or cracks may be formed in the film. It is necessary to improve the processability of the film itself.
JP-A-1-249331, JP-A-2-57339
The method indicated in the item has been proposed. However, T
In the process of laminating these polyester resin films on the FS, or in the process of drawing and redrawing, foreign matter such as dust may be mixed. Fine cracks may be formed in the laminated polyester resin film. For example, when the thinned deep drawn can is filled with a carbonated beverage, a sports beverage, or the like, and stored at room temperature for about one month, pitting may occur from the minute cracks. Therefore, there is a disadvantage that these steps must be strictly controlled.

As a method of laminating a polyester resin film on a tinplate, a method of temporarily bonding a polyester resin film at a temperature lower than the melting point of tin, and then heating the polyester resin film to a temperature higher than the melting point of tin (Japanese Patent Publication No. Sho 61). -3676),
TFS heated to a temperature equal to or higher than the melting point of the polyester resin,
A method of laminating a polyester resin film on a metal plate such as tinplate and quenching (Japanese Patent Publication No. 60-47103), a TF heated to the melting point of the copolyester resin ± 50 ° C.
A method of laminating a copolymerized polyester resin film coated with a specific adhesive on a metal plate such as S, tinplate, etc.
-249331) and the like. The polyester resin film laminated tinned steel sheet obtained by these disclosed methods is inferior in processing adhesion of the polyester resin film, severe processing adhesion, as compared with the polyester resin film laminated TFS obtained by the same method. It cannot be used for the thin-walled deep-drawing can of the present invention that requires processing corrosion resistance. In order to improve the processing adhesion and processing corrosion resistance, a polyester resin film is tin-plated with a large number of exposed parts of the steel sheet and tin-coated electrodeposited tin on the steel sheet surface using a tin plating solution of a specific composition. Discloses a surface-treated steel sheet on which a two-layer film made of chromium hydrated oxide and a lower layer of metallic chromium is formed, that is, a composite surface-treated steel sheet of tinplate and TFS. When the polyester resin film-laminated steel sheet obtained by this method is used for a thinning deep drawn can, the laminated polyester resin film does not peel off and the polyester resin laminated TFS
The corrosion resistance is superior to that of However, the manufacturing process of this surface-treated steel sheet is complicated, and it is difficult to control the tin plating that controls the exposed part of the steel sheet to a specific range, and when processed into a thinned deep drawn can, the appearance of the can body is slightly black. It has the drawback of adding taste and reducing commercial value.

[0005]

As described above, the technique for manufacturing a thin-walled deep-drawn can has many advantages as compared with the conventional can-making technique, but there is no suitable material. The present invention is directed to a thermoplastic resin-coated tin-coated steel sheet capable of producing a resin-coated tin-coated steel sheet for a thin-walled deep-drawn can having excellent processing adhesion and processing corrosion resistance suitable for the thin-walled deep-drawn can in a simple process. It is to provide a manufacturing method.

[0006]

As a result of various studies, the present invention has revealed that a tin-plated steel sheet which is not subjected to a post-treatment such as electrolytic chromic acid treatment, or a steel sheet which is provided with a small amount of nickel plating on an upper layer thereof (hereinafter collectively referred to as "collectively"). Is heated to the melting point of tin in a non-contact state, and a thermoplastic resin film or a thermoplastic resin film coated with a specific adhesive is laminated under pressure and quenched at the same time. Thus, a resin-coated tin-plated steel sheet for a thinned deep drawn can having excellent processing corrosion resistance can be obtained.

Hereinafter, the contents of the present invention will be described in detail. The method for producing the resin-coated tin-plated steel sheet for a thin-walled deep-drawn can with excellent processing corrosion resistance according to the present invention is described below (1) to (1).
(3), which are characterized. (1) No post-treatment such as electrolytic chromic acid treatment, which is usually applied to tinplate, after tin plating on both sides of the steel sheet or after further plating a small amount of nickel thereon. (2) This tin-plated steel sheet is heated to a temperature higher than the melting point of tin in a non-contact state to melt the plated tin, and a thermoplastic resin film is immediately laminated on both sides thereof. (3) The thermoplastic resin film is rapidly cooled to a temperature equal to or lower than the melting point of tin simultaneously with the lamination under pressure to solidify the molten tin.
Completing the lamination of the resin film.

First, tin plating on a steel sheet in the present invention may be performed using a known tin plating bath used for producing tinplate, for example, a ferrostan bath or a halogen bath, under known tin plating conditions. After tin plating, without subjecting to the usual electrolytic chromic acid treatment, washing and drying, or after washing with water, a known nickel plating bath, for example, a watt bath, a sulfamic acid bath, a small amount of nickel plating, Wash and dry. Tin plating amount Mai has good range 1.5~7.4g / ^{m 2.} More preferably, it is in the range of 2.0 to 5.6 g / m ² . When the tin plating amount is 1.5 g / m ² or less,
When laminating a thermoplastic resin film, the tin-plated steel sheet is heated above the melting point of tin, so most of the plated tin becomes an iron-tin alloy. The layers are broken and the laminated thermoplastic resin film peels off. Even if the film does not peel off, the processing corrosion resistance is significantly degraded. Also, as the amount of tin plating increases, even when an iron-tin alloy layer is formed when laminating a thermoplastic resin film, the amount of metallic tin remaining on the surface layer increases, and processing into a thinned deep drawn can is performed. The destruction of the iron-tin alloy layer at the time is reduced. However, if the amount of tin plating increases, the thermoplastic resin film laminated from the tin-plated steel sheet at the time of drawing becomes too stretched, and the film tends to peel off. Therefore, the upper limit of the amount of tin plating should be 7.4 g / m ^2. Is preferred.

In the case of applying nickel plating after tin plating,
Nickel plated on tin can be easily alloyed with tin by heating at the time of laminating the thermoplastic resin film or even at room temperature, and thus has an effect of improving the processing adhesion of the laminated thermoplastic resin film. At a nickel plating amount of 0.01 g / m ² or less, there is almost no effect.
In addition, the increase in the amount of nickel plating does not cause any particular problem when the amount of tin plating is large, but when the amount of tin plating is small, the amount of metal tin decreases due to the formation of a tin-nickel alloy, and the processing corrosion resistance decreases. It is dangerous and not preferred. Metallic tin has the effect of electrochemically protecting the exposed steel sheet surface when fine cracks enter the thermoplastic resin film laminated by severe processing, so in the present invention, from the viewpoint of corrosion resistance after processing Even after lamination of the thermoplastic resin film, it is essential that the metal tin remains. Considering the suitable range of the amount of tin plating in the present invention, the amount of nickel plating is preferably in the range of 0.01 to 0.20 g / m ² . Nickel plating applied after tin plating further improves the processing adhesion of the thermoplastic resin film laminated as described above,
It becomes possible to manufacture a thermoplastic resin-coated tin-plated steel sheet excellent in both processing adhesion and processing corrosion resistance continuously and in a stable state.

Next, the fact that post-treatment such as electrolytic chromic acid treatment is not required after tin plating or further nickel plating in the present invention will be described. In general, tinned steel sheets for food cans and beverage cans, so-called tinplates, are often painted and used as described above, and have excellent properties such as paintability, paint adhesion, and corrosion resistance after painting. Is required. Therefore, in order to prevent tin surface oxidation during storage and obtain tinplate excellent in these characteristics, after tin plating, it is subjected to cathodic electrolytic treatment in a chromic acid solution containing an auxiliary agent such as sodium dichromate or sulfuric acid. ing. However, in the present invention, this electrolytic chromic acid treatment is unnecessary because it eventually lowers the processing adhesion of the thermoplastic resin film. Certainly, the chromium hydrated oxide film formed by electrolytic chromic acid treatment or the two-layer film consisting of chromium metal as the lower layer and chromium hydrated oxide as the upper layer has excellent processing adhesion with the coating film or thermoplastic resin film. However, the processing adhesion with the tin layer or the tin-nickel alloy layer is poor, and when severe deep drawing is performed, it may peel off from the interface. Also, when this electrolytic chromic acid treatment is applied, the reason is not known,
The growth of the iron-tin alloy by heating is remarkably promoted. In particular, when the amount of tin plating is small, most of the plated tin is iron-tin alloyed, the remaining amount of metallic tin is reduced, and the anticorrosion effect of the electrochemical steel on the metal by metallic tin is also reduced. Is not preferred.

In the present invention, since this electrolytic chromic acid treatment is not performed after tin plating, the plated tin surface or tin-nickel alloy layer surface is naturally oxidized in a process until a thermoplastic resin film is laminated. However, even if these oxide films are present on the tin-plated steel sheet, the thermoplastic resin film is heated to a temperature equal to or higher than the melting point of tin immediately before laminating the thermoplastic resin film. It is considered that since the films are laminated under pressure, these oxide films are destroyed, and the thermoplastic resin film laminated with the active metal tin or tin-nickel alloy comes into direct contact, and excellent adhesion is obtained. Lamination of the thermoplastic resin film may be connected as a subsequent step of the continuous tin plating equipment or may be performed by another equipment, but the former is more preferable from the viewpoint of productivity and cost.

Next, the method of heating the tin-plated steel sheet is performed by preheating the tin-plated steel sheet to a temperature lower than the melting point of tin, in addition to resistance heating and high-frequency induction heating which are generally used in the manufacture of tinplate. A method of directly contacting the tin surface, such as a method using a roll, can also be used.However, in order to heat to a temperature higher than the melting point of tin, high-frequency induction heating, infrared radiation heating, heating with a laser beam, and the like are used in a non-contact manner. It is essential in the present invention to use a heating method that can raise the temperature to that temperature in a short time. Although there is no particular limitation on the atmosphere during heating, it is more preferable to use an inert gas atmosphere because it suppresses oxidation of the surface of the molten tin or tin-nickel alloy.

For pressure lamination and cooling of the thermoplastic resin film, a pair of rolls made of silicon rubber or fluorine rubber are used. The average pressure during the lamination and cooling of the thermoplastic resin film by this roll is 1.5 kgf /
cm ² or more. 1.5kgf / cm
^If it is ² or less, the tin or nickel oxide film on the surface is not sufficiently destroyed, and the contact between the active metal tin or tin-nickel alloy surface and the laminated thermoplastic resin film is insufficient, resulting in excellent adhesion. Cannot be obtained. The average pressing force is sufficient as long as the thermoplastic resin film to be laminated does not cause plastic deformation, and 30 kgf / cm ² or more is not required. In general, when a film is laminated on a steel strip using a roll, a part of the roll in the circumferential direction is deformed by pressure and is in contact with the steel strip within a certain length range. The length of contact is called the nip length, and the average pressing force already described is the total pressing force applied to this roll divided by the nip length x the width of the steel strip (contact area). is there.
In addition, the time of the pressurized lamination cooling by the roll is determined by the nip length and the lamination speed of the thermoplastic resin film, and the time is preferably in the range of 0.003 to 0.5 seconds. If the time is less than 0.003 seconds, the cooling by the roll is insufficient, and the excellent adhesiveness of the laminated thermoplastic resin film cannot be secured. Even if the pressure lamination cooling time is 0.5 seconds or longer, there is no particular problem from the viewpoint of the adhesion of the thermoplastic resin film, but it is not preferable from the viewpoint of high-speed continuous productivity of the resin-coated tin-plated steel sheet of the present invention.

A thermoplastic resin film having a crystal melting temperature (Tm) of 190 to 250 ° C. is suitable for the resin film to be laminated in the present invention. When laminating a thermoplastic resin film on a tin-plated steel sheet heated to a temperature equal to or higher than the melting point of tin, although the film is cooled by a roll at the same time as lamination, the surface temperature of the film is cooled to 190 ° C. or less within the lamination cooling time. This is difficult, and a film having a Tm of 190 ° C. or less melts and sticks to a roll, so that it cannot be continuously and uniformly laminated on a tin-plated steel sheet at a high speed. Tm2
A thermoplastic resin film having a temperature of 50 ° C. or higher is inferior in processability of the film itself, and is not suitable for a thin-walled deep-drawing can requiring strict processing adhesion, which is the object of the present invention. Specific examples include a polyester resin film and a polyamide resin film. As a polyester resin film,
For example, it is preferable that 75 to 95% of the ester repeating units are composed of ethylene terephthalate units, and the remaining 5 to 25% of the ester repeating units are composed of ester units other than ethylene terephthalate units, and the acid component other than terephthalic acid is phthalic acid. And one or more acid components of isophthalic acid, succinic acid, adipic acid, sebacic acid, dodecandioic acid, diphenylcarboxylic acid, 2,6 naphthalenedicarboxylic acid, 1,4 cyclohexanedicarboxylic acid, and trimetic anhydride. Can be Alcohol components other than ethylene glycol include 1,4 butanediol, 1,5 pentanediol, 1,6 hexanediol, propylene glycol, polytetramethylene glycol, trimethylene glycol, triethylene glycol, neopentyl glycol, 1,4 One or more saturated polyhydric alcohols such as cyclohexanedimethanol, trimethylolpropane, and pentaerythritol are mentioned. The ester unit other than the ethylene terephthalate unit may be any one or both of the acid component and the alcohol component as long as it is an acid component other than terephthalic acid and a polyhydric alcohol other than ethylene glycol. Can be used to obtain a copolymerized polyester. Further, a copolymer polyester similar to the above, in which 75 to 95% of the ester repeating units are butylene terephthalate units, can also be used.
As the polyamide resin film, nylon 6, nylon 66, nylon 11, nylon MXD6 or the like is used. These thermoplastic resins are used as both unstretched films and unstretched films that are stretched in two directions in the longitudinal and transverse directions after film formation by a known extruder. In particular, it is more preferable to use a polyester resin film having excellent workability disclosed in JP-A-1-249331. The thickness of the thermoplastic resin film used is 5
Those having a thickness of from 50 μm to 50 μm are preferable in terms of strength and economy.

In the present invention, the resin-coated tin-plated steel sheet obtained by directly laminating the above-mentioned thermoplastic resin film on a tin-plated steel sheet heated to a temperature not lower than the melting point of tin has excellent processing adhesion and excellent processing. Although it has corrosion resistance, when it comes into contact with more corrosive contents, the surface of the tin-plated steel sheet is corroded through the thermoplastic resin layer, and the thermoplastic resin film may peel off. When an adhesive layer is interposed between the thermoplastic resin film and the plated tin layer, the adhesive layer prevents corrosion on the surface of the tin-plated steel sheet, and as a result, prevents peeling of the thermoplastic resin film. This effect is thought to be due to the fact that the intervening adhesive layer is made of a thermosetting resin and has a superior barrier property to highly corrosive contents despite being thin compared to the thermoplastic resin layer. . A known adhesive may be used as the adhesive, but a polymer composition having an epoxy group in the molecule is more preferable, and this adhesive is applied to a surface in contact with a tin-plated steel sheet,
By using a dried thermoplastic resin film,
A resin-coated tin-plated steel sheet having more excellent corrosion resistance can be obtained.

[0016]

EXAMPLES Examples of the present invention and comparative examples will be described below.

Example 1 A cold rolled steel sheet having a thickness of 0.18 mm and a temper degree of DR-10 was prepared.
Both sides are degreased and pickled by a known method, washed with water, and (1)
Apply tin plating under the conditions shown in
Polyester resin foil on both sides of the steel sheet under the conditions shown in (2).
The film was laminated. After lamination, it was heated at 210 ° C. for 1 minute.
The obtained polyester resin-coated tin-plated steel sheet was converted to (3).
It processed into the thinning deep drawing can under the processing conditions shown. (1) Tin plating conditions Bath composition Tin sulfate: 80 g / l Phenolsulfonic acid (acidity converted to sulfuric acid): 15
g / l ethoxylated α-naphthol: 10 g / l bath temperature: 45 ° C. cathode current density: 20 A / dm²  Tin plating amount: 1.8 g / m²  (2) Lamination conditions of polyester resin film Characteristics of the film Composition: terephthalic acid 88 mol%, isophthalic acid 12 mol
%, Ethylene glycol 100 mol%
A. Biaxially stretched copolymerized polyester resin film Thickness: 25 μm Melting point: 230 ° C. Application of adhesive to film Adhesive composition: 80 parts epoxy resin 20 parts paracresol resole 20 parts Coating amount: 0.25 g / m²(Dry weight) Drying temperature: 100 ° C. Film lamination conditions Temperature of tin-plated steel sheet immediately before film lamination: 258 ° C. Pressure lamination time by laminating roll: 0.1 second Average pressing force during lamination: 10 kgf / cm²  Temperature of laminated roll: 95 ° C (3) Processing conditions for thinning deep drawn cans A. Drawing conditions Planck diameter: 187 mm Drawing ratio: 1.50 Redrawing processing conditions Primary redrawing ratio: 1.29 Secondary redrawing ratio: 1.24 Tertiary redrawing ratio: 1.20 Curvature radius at corner of redrawing die: 0.4 mm Redrawing process Holding load at 6000 kg: average thinning rate of can body: -20%

Example 2 On both sides of the cold-rolled steel sheet used in Example 1, (1) of Example 1
The tin plating amount is 5.6 g / m under the indicated tin plating conditions.²No tin
After washing with water and drying, the same composition used in Example 1 was used.
Laminate the film under the conditions shown in (1) without applying adhesive.
Layered. The obtained polyester resin-coated tin-plated steel sheet
Under the conditions shown in (3) of Example 1, it was processed into a thinned deep drawn can.
Was. (1) Polyester resin film laminating conditions Temperature of tin-plated steel sheet immediately before laminating the film: 270 ° C Pressing laminating time by laminating roll: 0.05 seconds Average pressing force during lamination: 5.5 kgf / cm²  Laminating roll temperature: 105 ° C

Example 3 On both sides of the cold-rolled steel sheet used in Example 1, (1) of Example 1
2.8 g / m of tin plating under the indicated tin plating conditions²No tin
After washing with water, nickel plating is applied under the conditions shown in (1).
And washed with water and dried. Further, as shown in (2) of Example 1.
The polyester resin film was laminated under the conditions described above. Get
The polyester resin-coated tin-plated steel sheet of Example 1
Under the conditions shown in (3), it was processed into a thinned deep drawn can. (1) Nickel plating conditions Bath composition Nickel sulfate: 250 g / l Nickel chloride: 30 g / l Boric acid: 30 g / l pH: 3-4 Bath temperature: 50 ° C. Cathode current density: 5 A / dm²  Nickel plating amount: 0.02 g / m²

Example 4 The cold rolled steel sheet used in Example 1 was subjected to (1) of Example 1 on both sides.
3.6 g / m of tin plating under the indicated tin plating conditions²No tin
And then washed with water and dried. Furthermore, the condition shown in (1)
To laminate a polyamide resin film. After lamination, 210
Heated for 1 min. The resulting polyamide resin-coated tin plating
Thinned deep drawn cans under the conditions shown in (3) of Example 1
Processed to. (1) Lamination conditions of polyamide resin film Film properties Composition: Nylon 6 Thickness: 25 μm Melting point: 225 ° C. Application of adhesive to film Adhesive composition: 80 parts epoxy resin 20 parts paracresol resole 20 parts Coating amount: 0.25 g / m²(Dry weight) Drying temperature: 100 ° C. Film lamination conditions Temperature of tin-plated steel sheet immediately before film lamination: 258 ° C Pressure lamination time by laminating roll: 0.01 sec Average pressing force during lamination: 5 kgf / cm²  Laminating roll temperature: 120 ° C

Comparative Example 1 Both surfaces of the cold-rolled steel sheet used in Example 1 were tin-plated with a tin plating amount of 1.8 g / m ^{2 under} the tin plating conditions shown in (1) of Example 1, and washed with water. Electrolysis in an aqueous solution containing 30 g / l of chromic anhydride and 0.3 g / l of sulfuric acid at a temperature of 50 ° C. and a cathode current density of 50 A / dm ² , 40 mg / m ² of chromium metal and chromium water on the plated tin Oxide 14mg /
A two-layer coating consisting of m ² (as chromium) was formed.
Further, a polyester resin film was laminated under the conditions shown in (2) of Example 1. The obtained polyester resin-coated tin-plated steel sheet was processed into a thin-walled deep drawn can under the conditions shown in (3) of Example 1.

Comparative Example 2 The cold-rolled steel sheet used in Example 1 was tin-plated on both sides under the tin plating conditions shown in (1) of Example 1 with a tin plating amount of 0.9 g / m ² , washed with water and dried. . Furthermore, (2) of Example 1
A polyester resin film was laminated under the following conditions. After lamination, it was heated at 210 ° C. for 1 minute. The obtained polyester resin-coated tin-plated steel sheet was processed into a thin-walled deep drawn can under the conditions shown in (3) of Example 1.

COMPARATIVE EXAMPLE 3 Both surfaces of the cold-rolled steel sheet used in Example 1 were tin-plated with a tin plating amount of 2.8 g / m ^{2 under} the tin plating conditions shown in (1) of Example 1, and washed with water and dried. Example 1 (1) of Example 2 except that the polyester resin film of the same composition used in Example 1 was not coated with an adhesive and the average pressing force at the time of lamination was 0.5 kgf / cm ^2. Laminated under the conditions. The obtained polyester resin-coated tin-plated steel sheet was used in Example 1 (3).
Under the conditions shown in the table below, it was processed into a thinned deep drawn can.

Comparative Example 4 Both sides of the cold-rolled steel sheet used in Example 1 were subjected to the conditions shown in (1).
Electrochromic treatment, chromium metal, chromium hydrate oxidation
To form a two-layer film made of a material, a so-called TFS film,
After washing with hot water and drying, a polyester tree was obtained under the conditions of (1) of Example 2.
A fat film was laminated. Obtained polyester resin coating
Thinning deep drawn cans under TFS conditions of Example 1 (3)
Processed to. (1) Electrochromic acid treatment conditions Bath composition Chromic anhydride: 30 g / l Sodium fluoride: 1.2 g / l Bath temperature: 45 ° C. Cathode current density: 40 A / dm²  Metal chromium amount: 104mg / m²  Chromium hydrated oxide amount: 16 mg / m²(With chrome
hand)

The peeling state of the laminated resin film in the step of processing the resin-coated steel sheets obtained in Examples 1 to 4 and Comparative Examples 1 to 4 into a thinned deep drawn can was visually observed. In addition, 1.5%
Filled with citric acid aqueous solution, stored in a constant temperature room at 37.5 ° C for 3 months, measured the amount of eluted iron by atomic absorption method, and calculated the incidence of leaking cans due to pitting corrosion. The results are shown in Table 1. Was. The amount of eluted iron was shown as an average value of 50 cans. In addition,
As the resin-coated steel sheet based on the tin-plated steel sheets of Comparative Examples 1 to 3 was processed into a thinned deep-drawing can, since the laminated polyester resin film was peeled off as shown in Table 1,
No 1.5% citric acid aqueous solution was charged.

[0026]

[Table 1]

[0027]

According to the method of the present invention, the resin-coated tin-plated steel sheet for thin-walled deep-drawn cans having excellent working corrosion resistance is used not only for thin-walled deep-drawn cans having various advantages but also for excellent work adhesion. Because of its excellent properties and excellent processing corrosion resistance, it can be widely applied as container materials such as drawn cans, can lids, easy-open can lids, crowns and caps.

Continuation of front page (56) References JP-A-58-82717 (JP, A) JP-A-1-192545 (JP, A) JP-A-2-251441 (JP, A) JP-A-63-40689 (JP) , A) JP-A-64-22530 (JP, A) JP-A-2-265740 (JP, A)

Claims (3)

(57) [Claims] 1. 1.5 to 7.4 g per side on both sides of a steel sheet
/ M ² of tin plating, or after tin plating, and then nickel plating of 0.01 to 0.2 g / m ² per side on the upper layer, and in a non-contact state, at a temperature equal to or higher than the melting point of tin. And immediately melt on both sides with a crystal melting temperature of 190-2.
A thermoplastic resin film of 50 ° C. is applied with a pressing force of 1.5 to 30.
A thin-walled deep-drawing can excellent in processing corrosion resistance characterized in that it is laminated under pressure under the conditions of kgf / cm ² and a lamination time of 0.003 to 0.5 seconds, and is rapidly cooled to a temperature equal to or lower than the melting point of tin. For producing resin-coated tin-plated steel sheets. 2. The resin-coated tin-plated thin-drawing can with excellent working corrosion resistance according to claim 1, wherein an adhesive is applied in advance to the surface of the thermoplastic resin film to be laminated, which is in contact with the tin or nickel-plated surface. Steel plate manufacturing method. 3. The method according to claim 1, wherein the thermoplastic resin film to be laminated is a polyester resin film or a polyamide resin film.