JP2937788B2 - Manufacturing method of resin-coated steel sheet for dry drawing and ironing can - 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 two-piece can material produced by processing including ironing. Specifically, without cooling or lubrication with water or a water-based lubricant, there is no need to clean the cans after making them, and heat suitable for manufacturing two-piece cans with thin-walled cans by processing including ironing. The present invention relates to a method for producing a plastic-coated steel sheet.

[0002]

2. Description of the Related Art Conventionally, as a two-piece can in which a can body and a can bottom are integrated, a DRD made of a tin plate, an aluminum plate, an aluminum alloy plate, an electrolytic chromic acid-treated steel plate or the like is used.
Cans (Drawn and Reddraw Can),
DI cans (Drawn and Ironed Can) are common, and in recent years, DTR cans (Draw-Thin /
(Redraw Can) has also been put to practical use. Since the DRD can is manufactured by drawing and redrawing, the can wall thickness increases in proportion to the can height. Therefore, from the viewpoint of economy, it is generally applied to cans having a low can height, and as a base metal plate, an electrolytic chromic acid-treated steel plate, a tin plate, and an aluminum alloy plate are used. On the other hand, DI cans manufactured by ironing after drawing can be economically applied to cans with a high can height because the can wall thickness can be reduced to about 1/3 of the original plate thickness. A tinplate and an aluminum alloy plate are used. Also, the DRD can and the DI can are greatly different in that the metal plate in which the DRD can is previously coated with an organic film is drawn, whereas the DI can is painted after ironing. This is because the degree of processing and the stress state during processing are greatly different between DRD processing and DI processing. When the metal sheet coated with an organic film is applied to DI processing, which is a processing with extremely high degree of processing and surface pressure on the can wall, it is practical due to seizure of the organic film on the mold, damage to the organic film on the inner and outer surfaces, etc. It has not been converted.

On the other hand, DTR cans are manufactured by making the shoulder radius at the time of redrawing small and making the can wall thin while applying a large tensile force to bending and unbending at the shoulder. DTR cans are manufactured by a process very similar to drawing, but in order to stretch the can wall,
The can wall is slightly thinner than the original plate thickness. Also, unlike ironing, a large surface pressure is not applied to the can wall between the die and the punch, so the load on the organic film is not so large, the organic film is not easily damaged, and the organic film coated metal A plate can be applied, and at present, an electrolytic chromic acid-treated steel sheet coated with a thermoplastic resin is industrially used. However, in the case of the DTR can, since the processing is mainly performed by the tensile force, the can wall is easily broken during the processing,
The can wall thickness is about 80% of the original plate thickness, which is thicker than the DI can wall.

[0004] As described above, DRD cans, DI cans, DTR cans, and methods for producing them each have advantages and disadvantages. Here, in the present invention, the can height is about twice as large as the can diameter, such as DI can, and the can wall thickness is 70 times the original plate thickness.
An object of the present invention is to provide a method for producing a steel sheet coated with a thermoplastic resin on both sides, which is suitable for obtaining a thin can of about 40%. In processing, it is an object of the present invention to provide a method for producing a thermoplastic resin-coated steel sheet which can omit the use of an emulsion system, a water-soluble lubricant, or the like which is currently used for cooling and lubrication in the production of DI cans. In advance, by using a steel sheet laminated with a thermoplastic resin, the omission of paint baking in the can making process and the scattering of the solvent can be prevented.Furthermore, by using no coolant and lubricant, the subsequent cleaning, Drying and waste liquid treatment can be omitted. That is, a thermoplastic resin metal plate capable of producing a can having a high can height and a thin can wall thickness without such water-based cooling, using a lubricant, and not requiring cleaning of the can after can production. No disclosure is found of course, and no disclosure is found of such cans and their manufacture. Although not having the same purpose as the present invention, the following are related.

Japanese Patent Application Laid-Open No. 62-275172 relates to an organic resin-coated metal plate for a two-piece can. In ironing, it is necessary to enhance the retention of coolant (water-based cooling, lubricant) on the outer surface where processing is severe. This is one of the issues. In other words, it is based on the premise that water-based cooling and the use of a lubricant are used, which greatly differs from the object of the present invention. Japanese Patent Publication No. 2-501638 also discloses a method of processing a metal sheet obtained by laminating a polyester resin film on one or both sides of the metal sheet into a DI can. Although the subsequent can cleaning process has been simplified, the use of a lubricant that requires cleaning of the can after cleaning is required in the squeezing process, and cleaning of the can after manufacturing is completely eliminated. It is not considered. Japanese Patent Application Laid-Open No. Hei 4-91825 discloses that a metal wall coated with a thermoplastic resin can be water-cooled without using a lubricant, that is, a high-temperature volatile lubricating substance is used as a lubricant, and the can wall is thinned by bending and bending back. This is related to what is called DTR processing, but as shown in the examples, the degree of thinning is about 20%, which is smaller than the target value of the present invention.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a can having a height as high as twice as large as the can diameter and a can wall having a thickness as small as 70 to 40% of the original plate thickness. An object of the present invention is to provide a method for producing a thermoplastic resin-coated steel sheet that can form a two-piece can without water-based cooling and without using a lubricant (hereinafter, referred to as a dry method) and does not require cleaning of the can after can-making. By reducing the thickness of the can wall to 70 to 40% of the original plate thickness, the can height increases in proportion to the degree of the reduction in thickness. Although this point fulfills the object of the present invention, as the degree of thinning increases, adhesion of the mold to the outer surface of the can wall, damage to the surface resin layer, and breakage of the can wall tend to occur. In particular, water-based cooling,
In the present invention, which does not use a lubricant, damage to the resin layer on the outer surface of the can and resulting breakage of the can wall are liable to occur. In addition, as the degree of work increases, the adhesion between the base steel sheet and the laminated resin layer decreases, but it is also an object of the present invention to provide a resin-coated steel sheet with sufficient adhesion. is there.

[0007]

The method for producing a resin-coated steel sheet for dry drawing and ironing cans according to the present invention is as follows.
-0.06%, Mn content: 0.05-0.50%, Al content:
0.015-0.13%, Si content ≦ 0.05%, P content ≦ 0.1%
A hot-rolled sheet having an S content of 0.03% and the balance of Fe and unavoidable impurities is pickled, cold-rolled, and continuously annealed, then rolled at a rolling ratio of 5 to 25%, and center line averaged. Roughness: 0.
0.05 to 0.6 μm, thickness: 0.15 to 0.30 mm,
Then, it is treated with electrolytic chromic acid, and then the thickness of 10
It is characterized in that a thermoplastic resin of about 50 μm is coated, and a high-temperature volatile lubricant is applied to the surface thereof. Further, the method for producing a resin-coated steel sheet for dry drawing and ironing cans of the present invention,
C content: 0.001 to 0.06%, Mn content: 0.05 to 0.5%
50%, Al content: 0.015 to 0.13%, Si content ≦ 0.1
Pickling a hot rolled sheet having a P content of 0.05%, an S content of 0.03%, and an S content of 0.03%, with the balance being Fe and unavoidable impurities;
Cold rolling, continuous annealing, after overage treatment, rolling rate 5-25%
The center line average roughness: 0.05 to 0.6 μm, the plate thickness: 0.15 to 0.30 mm, and then electrolytic chromic acid treatment, and then a thermoplastic resin with a thickness of 10 to 50 μm on both surfaces And applying a high-temperature volatile lubricant to the surface thereof. And the manufacturing method of the resin-coated steel plate for dry drawing and ironing cans of the present invention is as follows.
0.06%, Mn content: 0.05 to 0.50%, Al content:
0.015-0.13%, Si content ≦ 0.05%, P content ≦ 0.1%
03%, S content ≦ 0.03%, Nb, T
One or two of i and B are respectively 0.001 to
0.03%, 0.005 to 0.05%, 0.001 to 0.0
A hot rolled sheet containing 1%, the balance being Fe and unavoidable impurities, was pickled, cold rolled, continuously annealed, and then subjected to a rolling reduction of 5 to 2
5%, center line average roughness: 0.05 to 0.6 μm, plate thickness:
0.15 to 0.30 mm, then electrolytic chromic acid treatment, thereafter coating both sides with a thermoplastic resin having a thickness of 10 to 50 μm, and applying a high-temperature volatile lubricant to the surface. In such a production method, it is desirable that the thermoplastic resin is a crystalline polyester resin, and it is preferable that the thermoplastic resin layer be coated with an adhesive after electrolytic chromic acid treatment and adhered thereon.

[0008]

As described above, the chemical composition of the steel sheet, the annealing method, the rolling ratio after annealing, the surface roughness after rolling, the type of surface treatment, and the characteristics of the laminated thermoplastic resin are determined. Dry workability by applying a lubricant
A dry-drawn and ironed can-coated resin-coated steel sheet excellent in can strength, adhesion after processing, and corrosion resistance is obtained. Here, in order to carry out the dry processing at a higher processing degree without any problem, it is desirable that the processing method is also suitable for the purpose of the present invention. The processing of the resin-coated steel sheet according to the present invention is a combined processing method in which redrawing and ironing are performed under specific conditions, that is, reduction of damage to the thermoplastic resin layer laminated on the inner and outer surfaces and rupture of the can wall. By processing by the thick processing method, the features of the resin-coated steel sheet according to the present invention are:
It is more effective. Further, as the thermoplastic resin, a polyethylene terephthalate resin and a copolymerized polyester resin mainly composed of ethylene terephthalate units are more suitable. Further, the high-temperature volatile lubricant is applied to the upper surface of the laminated thermoplastic resin layer in order to enhance dry workability, and the high-temperature volatile lubricant can be removed by heating after molding, Steps such as degreasing, washing with water, and drying can be omitted.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reasons for limiting the present invention and the operation thereof will be described below in detail with reference to the drawings. FIG. 1 is a schematic view showing a cross section of the resin-coated steel sheet for dry drawing and ironing can according to the present invention. FIG. 2 shows that the can height is high from the resin-coated steel sheet for dry drawing and ironing can according to the present invention. A thin can with a can wall
FIG. 3 is a schematic view of one embodiment of a process of forming in a dry process, and FIG. 3 is a process of dry forming a thin can having a high can height from a resin-coated steel plate for a dry drawing and ironing process according to the present invention. FIG. 4 is a schematic diagram of a partial cross section of a combined machining that performs redrawing and ironing simultaneously, which is suitable for performing
FIG. 5 is a cross-sectional view of a can formed from the resin-coated steel sheet for dry drawing and ironing can according to the present invention. FIG. 5 is a profile of the can wall thickness of the can formed from the resin-coated steel sheet for dry drawing and ironing can according to the present invention. It is a figure showing an example of. An object of the present invention is to obtain a resin-coated steel sheet that can be dry-processed to reduce the thickness of a can wall to 70 to 40% of the original sheet thickness, and that has excellent can strength, corrosion resistance, and adhesion. It has been derived as a result of many studies including this. The object of the present invention is to obtain a steel sheet laminated with a thermoplastic resin on both sides, which is suitable for dry-type and for reducing the thickness of a can wall with a large working ratio. What is caused is heat generated by processing, softening and melting of the laminated thermoplastic resin layer due to the heat, resulting in direct contact between the base steel sheet and the mold, and further, breakage of the can wall. The heat generated by processing is affected by the deformation and friction of the metal plate.
In addition, in the ironing process in the composite machining shown in FIG. 3 which is desirable for the present invention, the smaller the deformation resistance, the lower the surface pressure, and the smaller the frictional heat generated in proportion to the surface pressure × the coefficient of friction. Also, even if the temperature of the laminated resin layers is the same,
The smaller the surface pressure, the less damage to the resin layer. Therefore, regarding the damage to the resin layer, the smaller the amount of deformation and the smaller the deformation resistance of the material as much as possible, the less the damage to the resin layer even if the degree of processing is the same. here,
Since the material undergoes drawing and redrawing before the ironing in FIG. 3, it is more suitable for the purpose of the present invention that the hardening due to the processing is smaller. As described above, the chemical composition of the steel sheet is determined from the viewpoint that the deformation resistance is small even after the working.

First, the reason for determining the chemical composition of a steel sheet will be described. C hardens steel by increasing its amount,
And refine the crystal grains. When the crystal grains are fine, the surface roughness due to processing is small, and it is desirable in terms of adhesion to the laminated thermoplastic resin layer. However, when the crystal grains are small, the hardening due to processing increases. The hardening of steel is not suitable for dry drawing and ironing as the object of the present invention or necking of the can upper end after drawing and ironing, and the upper limit of the amount of C is 0.0.
6%. On the other hand, when the C amount becomes 0.001% or less,
Although the work hardening is small, the crystal grains are large, the re-drawing premised on the application of the present invention, the rough surface is likely to occur even in the ironing process, the work adhesion with the laminated thermoplastic resin layer, the stress concentration due to the rough surface is reduced. Occurs and easily breaks during processing.

[0011] Since Mn also hardens the steel, it is desirable that the amount is small, and the upper limit is limited to 0.5%. On the other hand, Mn is necessary to prevent hot brittleness due to S in steel,
The lower limit is set to 0.05%. Al is added as a deoxidizing agent, but if the deoxidizing residue is less than 0.015%, deoxidizing is unstable, while if it exceeds 0.13%, it hardens,
In addition, the cost is increased. When the amount of S increases, the amount of sulfide-based inclusions increases to deteriorate the workability and the corrosion resistance also decreases. Therefore, the upper limit is set to 0.03%. Si,
Each of P hardens steel and impairs dry workability, which is the subject of the present invention.
03%. The addition of Ti, Nb, and B is for reducing solid solution C and solid solution N in steel and suppressing work hardening. If the amount is less than the lower limit, the effect is insufficient. If the amount is more than the upper limit, the crystal grains are refined and work hardening becomes large, which is not suitable for dry processing. In order to make the addition of Ti, Nb and B more effective, it is desirable to keep the C content and the N content at small levels.
0.06, but preferably 0.001-0.03%
Range. Also, the amount of N is not limited,
It is desirable to make it 0.005% or less.

The reason why the recrystallization annealing after the cold rolling is continuous annealing or continuous annealing + overaging treatment will be described below. The drawn and ironed can to which the steel sheet according to the present invention is applied requires a high degree of homogeneity in material. Regarding the homogeneity of this material, continuous annealing is performed. Desirable continuous annealing conditions vary depending on the steel composition.
C. and a soaking time of 10 seconds to 3 minutes. After continuous annealing, if necessary, an overaging treatment is performed. By the overaging treatment, solid solution C and N are reduced, and hardening by subsequent processing becomes small. By reducing the work hardening, the load on the organic resin during the thickness reduction by drawing and ironing is small, and the can wall after the thickness reduction becomes soft, so that the neck-in workability afterwards is excellent. Becomes A soft and ductile can wall is suitable for neck-in processing, but when a high degree of neck-in workability is required, an overage treatment is performed. The overaging treatment is performed after continuous annealing, and is performed at 300 to 450
A heat treatment at about 30 seconds to about 10 minutes is included.

[0013] On the other hand, the processed can is used in a state where the pressure inside the can is positive or negative, and in order to withstand such pressure, both the can bottom and the can wall must have a certain strength. .
In particular, when the pressure inside the can is positive, the pressure resistance of the bottom of the can becomes a problem. However, the pressure resistance is roughly (plate thickness) ² × yield strength, which is directly proportional to the pressure resistance. Strength affects. Further, the required compressive strength differs depending on the contents. From the viewpoint of the pressure resistance, the lower limit of the rolling reduction after continuous annealing or after continuous annealing and overaging treatment is determined. When the rolling ratio is less than the lower limit, the thickness of the base steel sheet cannot be reduced from the viewpoint of the pressure resistance of the can bottom, and it is difficult to obtain an economical can. The upper limit of the rolling reduction is determined from the point of breaking of the can wall during drawing and ironing. Therefore, the rolling reduction is 5 to 25%, preferably 8 to 20%. The higher the rolling ratio, the more easily the can wall breaks. Therefore, the upper limit of the rolling ratio is set to 25%, but the likelihood of the can wall break depends on the composition of the steel, the manufacturing conditions of the steel sheet, and the like. When the C content in the steel is high, or when the drawing and ironing conditions are severe, the rolling reduction is desirably 20% at the maximum. Can wall breakage is likely to occur on the can wall in the vertical direction with respect to the rolling direction, but when the cementite in proportion to the C content is arranged in a fibrous form in proportion to the rolling ratio, the ductility in the rolling direction and the vertical position is impaired. It is thought to be. Here, assuming that the rolling reduction after the continuous annealing + overaging treatment is 5 to 25%, preferably 8 to 20%, the tensile yield strength in the rolling direction of the steel sheet is 33 to 58 kg / m, respectively.
m ² , about 35 to 55 kg / mm ² . Here, the thickness is determined with reference to the relationship between the yield strength and the thickness,
It is necessary to be 0.15 mm or more from the viewpoint of the pressure resistance of the bottom of the can. The upper limit is 0.3 mm from the viewpoint of economy.
And

Next, the resin to be laminated on the steel sheet is a thermoplastic resin, preferably a crystalline polyester resin, having a thickness of 10 to 50 μm, and a thickness of 180 to 260 μm.
A polyester resin having a melting point of ° C. The reason will be described. The present invention is premised on dry processing, but by making the laminated resin a thermoplastic resin,
The lubrication effect at the time of ironing becomes more effective. During ironing, the outer surface of the can generates heat due to friction with the ironing die, but is presumed to be softened by the heat and provide a lubricating effect. When the temperature of the ironing die is increased, the lubricating effect becomes remarkable, but when the temperature is further increased, the resin in the ironing die further softens and cannot withstand the surface pressure proportional to the deformation resistance of the steel plate. Are in direct contact, causing rupture of the can wall. Therefore, it is not preferable that the thermoplastic resin is excessively softened, and it is desirable that the ironing die temperature be in an appropriate temperature range, preferably 25 ° C. to the glass transition temperature of the thermoplastic resin to be laminated. On the other hand, it is not preferable that the laminated thermoplastic resin also softens at a low temperature. When the melting point is used as an index of the ease of softening, it is possible to use a thermoplastic resin having a melting point of 180 ° C. or more. It is more preferable because the formability of the steel sheet in the target dry processing is improved. That is, in industrial production, drawing and ironing are continuously performed. In that case, depending on the processing conditions, the can wall temperature may be 100 ° C. or higher, and when the melting point is low, the can is softened or melted. In addition, the appearance of the obtained can body is impaired, or an exposed iron portion is formed on the inner surface of the can body, and the corrosion resistance is reduced. Further, the thermoplastic resin adheres to the tool, making continuous production difficult. 1 from this point
It is preferable to use a thermoplastic resin having a melting point of 80 ° C. or higher. Further, the melting point of the laminated thermoplastic resin is 26.
If the temperature is 0 ° C. or higher, a sufficient lubricating effect due to softening during processing cannot be obtained. For the above reasons, it is more preferable that the upper limit of the melting point of the laminated thermoplastic resin is limited to 260 ° C. and the lower limit is set to 180 ° C. Further, the thickness of the laminated thermoplastic resin layer is set to 10 to 50 μm, and the thickness is set to 10 μm.
In the case of μm or less, the risk of direct contact between the ironing die and the base steel sheet on the outer surface of the can during ironing increases, and the risk of breakage of the can wall increases. Also, the corrosion resistance on the inner surface side of the can may be insufficient. Further, it becomes difficult to continuously and stably laminate the thermoplastic resin on the steel sheet. On the other hand, the upper limit of the thickness of the laminated thermoplastic resin is set at 5 from the viewpoint that wrinkles are likely to occur during drawing and that the cost is low.
Limited to 0 μm.

Among the thermoplastic resins having a melting point of 180 to 260 ° C., a more preferred resin is a polyester resin, and specifically, a copolymerized polyester resin mainly composed of polyethylene terephthalate, polybutylene terephthalate, and ethylene terephthalate units. Or a polyester resin comprising a mixture thereof. Especially 7
5 to 95 mol% of polyethylene terephthalate and 5-2
It is preferable to use 5 mol% of a copolymerized polyester resin such as polyethylene isophthalate, polyethylene sebacate, or polyethylepipate, or a polyester resin obtained by blending polyethylene terephthalate or the above polyester resin with polybutylene terephthalate.

As a method of laminating the above polyester resin on a steel sheet, a method of extruding and laminating a polyester resin melted directly on both surfaces of the steel sheet, and a method of subjecting an unstretched or stretch-oriented film formed into a film by a conventional method after melt extrusion to a conventional method. There is a method of laminating by fusion or through an adhesive, and a method of using these methods in combination.Either method is applicable as a method for producing the resin-coated steel sheet of the present invention, In the can, it is preferable to use a biaxially oriented polyester resin film from the viewpoints of impact resistance of the laminated resin layer, permeation resistance to highly corrosive contents, and the like. In that case, the plane orientation coefficient of the polyester resin layer laminated by heat fusion is 0.01 to 0.10 on the surface not in contact with the steel plate (free surface), and 0.000 to 0.05 on the surface in contact with the steel plate. It is most preferable to select the lamination conditions so as to fall within the range described above. That is, when the plane orientation coefficient of the surface of the laminated polyester resin layer in contact with the steel sheet is 0.05 or more, the laminated polyester resin layer is easily peeled off during processing, which is not practical.

On the other hand, when the plane orientation coefficient on the free surface of the laminated polyester resin layer is 0.01 or less,
The biaxial orientation of the polyester resin has almost disappeared, and if it is dry-formed into a drawn and ironed can, the laminated polyester resin layer may crack, making it difficult to fill highly corrosive contents. Difficult to use. On the other hand, if the plane orientation coefficient on the free surface exceeds 0.10, the spreadability of the laminated polyester resin layer becomes poor, and if the processing conditions become severe, the resin layer may crack during processing. Therefore, in the resin-coated steel sheet of the present invention, the plane orientation coefficient of the free surface of the laminated polyester resin layer is 0.01 to 0.10, and the plane orientation coefficient of the surface in contact with the steel sheet is 0.000 to 0.05. It is preferable to be within the range. Laminating the polyester resin film on a steel sheet via an adhesive layer is preferable for the inner surface of a can filled with highly corrosive contents, in which case, the plane orientation coefficient of the laminated polyester resin layer is preferable. Does not particularly need to be controlled as described above. Known adhesives can be used as the adhesive used, but a thermosetting polymer composition having an epoxy group in the molecule is more preferable, and is applied to the surface of the thermoplastic resin film that comes in contact with the steel sheet, or dried, or You may apply and dry on the surface of a steel plate.

The plane orientation coefficient of the laminated polyester resin layer is determined by the following method. First, a polyester resin-coated steel sheet is immersed in dilute hydrochloric acid to dissolve the steel sheet, and only the polyester resin layer is collected. Next, the collected polyester resin layer (film) is washed with water and dried,
Using a refractometer, the refractive index in each of the length direction, the width direction, and the thickness direction of each surface of the film (the surface in contact with the steel plate and the free surface) is measured. Using this refractive index, the plane orientation coefficient on each surface of the film is determined by the following equation. A = (B + C) / 2-D Here, A is the plane orientation coefficient of the film, B is the refractive index in the length direction of the film, C is the refractive index in the width direction of the film, and D is the thickness of the film. The refractive index in the vertical direction. Since the refractive index measured by the above method indicates an average value at a thickness within 5 μm from the surface of each surface of the film,
Each side of the film (surface in contact with steel plate and free surface)
Can be distinguished from each other.

Further, in the present invention, it is easy to control the plane orientation coefficient of the non-contact surface (free surface) of the polyester resin layer laminated by heat fusion and the surface in contact with the steel plate within a preferable range. Therefore, it is also possible to use a biaxially oriented film of a polyester resin composed of two layers of an upper resin and a lower resin having different melting points.

The IV value of the above polyester resin film
(Intrinsic viscosity, intrinsic viscosity) is also one of the important factors of the polyester resin film used in the present invention. The IV value is positively correlated with the molecular weight and is a factor that has a great influence on the rigidity of the film and the moldability of the resin film.
That is, when the IV value is 0.50 or less, even if the plane orientation coefficient of the polyester resin layer after lamination is in a preferable range, the impact resistance after forming into a drawn and ironed can is poor,
Numerous fine cracks are formed in the polyester resin layer on the inner surface side of the impacted portion, and the steel surface is exposed. When the IV value is 0.70 or more, the viscous resistance during ironing is high, which may cause a practical problem.

In the present invention, laminating a thermoplastic resin colored with a pigment on the outer surface of the steel plate can also be one of the important factors from an aesthetic point of view. That is, in order to improve the sharpness of the design printed on the outer surface of the can, a titanium oxide-based white pigment can be included in the resin production process. As the pigment, pigments of colors other than inorganic, organic, and white are also applicable, and are selected according to the application. Good printability can be obtained when the addition amount is 1 to 20%.

In the present invention, bisphenol A
Polycarbonate, 6-nylon, 6,6-nylon,
It is also possible to use a polyamide resin such as 6-6,6-copolymer nylon, 6,10-nylon, 7-nylon, 12-nylon, or a thermoplastic resin such as polyethylene naphthalate. Further, it is also possible to use these thermoplastic resins alone, a two-layer structure obtained by co-extrusion with the polyester resin, or as an upper layer of a three-layer film, or as an intermediate layer,
Further, it is also possible to use a resin obtained by blending these thermoplastic resins with the polyester resin. Further, a two-layer film provided with the above-mentioned polyester resin layer as an upper layer of the blend resin film is also applicable. It should be noted that additives such as a stabilizer, an antioxidant, an antistatic agent, a lubricant, and a corrosion inhibitor can be added to the above-mentioned thermoplastic resin as needed, as long as other properties are not impaired.

The steel sheet on which the thermoplastic resin is laminated is preferably an electrolytic chromic acid-treated steel sheet, and the center line average roughness of the steel sheet used is set to 0.05 to 0.6 μm because the thermoplastic resin laminated with the steel sheet is used. This is for achieving adhesion and corrosion resistance with the object. The film formed by the electrolytic chromic acid treatment is a film having a two-layer structure in which the lower layer is composed of chromium metal and the upper layer is composed of hydrated chromium oxide. The amount of chromium metal in the lower layer is 30 to 200 mg / m ² , and the amount of chromium in the upper layer is The amount of the hydrated oxide is preferably in the range of 5 to 25 mg / m ² as the amount of chromium. If the center line average roughness is 0.6 μm or more, the processing adhesion of the laminated thermoplastic resin becomes a problem depending on the processing conditions, and the laminated thermoplastic resin layer is peeled off at the upper end of the can with a high degree of processing. In some cases, the upper limit was set to 0.6 μm. Further, the lower limit is not from the viewpoint of performance, but it is economically difficult to stably produce a steel sheet having a center line average roughness of 0.05 μm or less. From this point, the lower limit is set to 0.05 μm.

The high-temperature volatile lubricant applied to the upper surface of the laminated thermoplastic resin layer is used for dry drawing and ironing, which is a subject of the present invention, at a high processing rate and at a high speed.
Play an important role. In addition, the high-temperature volatile lubricant, when heated for several minutes at a temperature of about 200 ℃ after processing, 50%
It is desirable that the particles be scattered as described above. Specifically, the material is selected from liquid paraffin, synthetic paraffin, natural wax, or other simple substance, or a mixture thereof according to processing conditions and heating conditions after processing. As a characteristic of the applied lubricant, the melting point is 2
Those having a boiling point of 5 to 80 ° C and a boiling point of 180 to 400 ° C are desirable for achieving the object of the present invention. The amount of application should be determined in consideration of the surface to be the outer surface of the can, the surface to be the inner surface of the can, processing conditions, heating conditions after processing, and the like.
A range of 00 mg / m ² , preferably 30-60 mg / m ² is suitable.

As described above, the chemical composition of the steel sheet, the annealing method, the cold rolling reduction after annealing, the surface roughness of the rolled sheet, the type of surface treatment, and the characteristics of the thermoplastic resin are limited. By applying a high temperature volatile lubricant on the plastic resin, the can height is twice as large as the can diameter by dry drawing and ironing, and the can wall thickness is about 70 to 40% of the original plate thickness. A resin-coated steel sheet suitable for forming a thin can having a can wall is obtained.

Here, the drawing and ironing will be described below. If the thickness of the can wall is reduced by the combined processing in which redrawing and ironing are performed simultaneously, the object of the present invention can be achieved very effectively. One embodiment of a process for producing a can having a high can height and a thin can wall thickness from the resin-coated steel sheet of the present invention by processing including the composite processing will be described below. First, as shown in FIG. 2, a blank 5 is punched from the resin-coated steel sheet according to the present invention shown in FIG. 1 to form a drawn can 6, and the drawn can 6 is redrawn in a smaller diameter than the drawn can 6. As shown in FIG. 3, the re-drawing can 7 is further re-drawn into a small-diameter can, and simultaneously the re-drawing can 7 is pressed and ironed at the same time to form a drawn and ironed can 8. Trims and trims 12
Then, the upper end portion of the can is neck-in (processing to reduce the diameter of the can), flanged, and finished in the final can shown in FIG. The can height, which is the subject of the resin-coated steel sheet of the present invention, is high,
Regarding obtaining a can having a thin can wall thickness, in the above-mentioned steps, the role of the composite processing is not limited, and the outline of the composite processing is shown in FIG.
Following 4, the ironing part 16 is arranged, and ironing is performed while performing redrawing. By performing the ironing while effectively applying the rearward tension to the ironed portion in this manner, the resin layer on the outer surface is less likely to be damaged. Also,
The length L of the can wall 10 between the redrawing part and the ironing part is:
The thickness is determined in consideration of the size to be thickened for the subsequent neck-in processing. If the temperature of the redrawing die 14 and the ironing die 15 is in the range of 25 ° C. to the glass transition temperature of the laminated resin, it is effective to solve the problem of the present invention. Here, the base plate thickness of the thermoplastic resin is 0.20 m
An example of the distribution of the can wall thickness (thickness of only the steel sheet from which the laminated resin layer has been peeled) in the can height direction of the can 12 obtained by processing the electrolytic chromic acid-treated steel sheet of m in accordance with the processing step of FIG. Is shown in FIG. In FIG. 5, the thickness of the can body is
Approximately 0.120mm (reduced by 40% of the original thickness), and the upper end of the can is approximately 0.160mm (20% of the original thickness)
) And is in a state suitable for subsequent neck-in processing. Further, as can be easily understood from the processing method of FIG. 3, when the outer diameter of the punch 13 is the same as the portion corresponding to the can body and the portion corresponding to the can upper end, the can body and the upper end of the can are provided. Is formed on the outer surface side of the can, which is the opposite state of the DI can having the thickness step on the inner surface side of the can. FIGS. 2, 3, 4, and 5 show embodiments in which a thickness step is formed on the outer surface of the can. On the other hand, as in the case of the DI can, if the outer diameter of the punch corresponding to the upper end of the can is reduced, it is needless to say that a thickness step is formed on the inner surface side of the can. Even if there is a step on the outer surface of the can, it hardly affects the appearance, and even if there is a step on the inner surface of the can, it hardly affects the removability of the punch of the can after molding. That is, even if the step is formed on either the inner surface side or the outer surface side, there is no problem in quality and manufacturing.

(Example 1) Six types of steels having the chemical compositions shown in Table 1 were melted in a converter, turned into slabs, hot-rolled at a finishing temperature of 900 ° C, and wound at 650 ° C. 8
mm hot rolled sheet. The hot-rolled sheet was pickled and then cold-rolled to obtain a cold-rolled sheet having a thickness of 0.18 to 0.30 mm. The annealing method shown in Tables 2 and 3 (CA: continuous annealing, CA + O)
A: Continuous annealing + overage treatment), and Tables 2 and 3
Then, 13 types of rolled sheets having a sheet thickness of 0.18 mm were prepared by rolling at the rolling ratios after annealing shown in (1). These rolled sheets were subjected to electrolytic chromic acid treatment (amount of chromium metal: 120 mg / m ² ,
Chromium in hydrated chromium oxide: 18 mg / m ² ), and coated with a thermoplastic resin in the following manner. First, these original plates were heated to 240 ° C., and a biaxially stretched copolyester resin film (thickness: 25 μm, surface: 88 mol% of polyethylene terephthalate, 12 mol% of polyethylene isophthalate) was formed on the inner surface of the can. Orientation coefficient: 0.126, melting point: 229 ° C., and biaxially stretched biaxially stretched copolyester resin film (thickness: 20 μm) of the same composition as described above colored with titanium oxide pigment and colored white on the outer surface of the can ) Were simultaneously laminated and immediately immersed in water and cooled. After lamination, drying was performed, and paraffin-based wax was applied on both sides at about 50 mg / m ^2, and the subsequent processing was performed. First, after punching into a blank having a diameter of 160 mm, a drawn can having a can diameter of 100 mm was obtained. Subsequently, a redrawn can having a can diameter of 80 mm was obtained by redrawing. This redrawn can was subjected to ironing simultaneously with redrawing by composite processing to obtain a drawn and ironed can having a can diameter of 66 mm. In this combined processing, the distance between the redrawing part and the ironing part, which is the upper end of the can, is 20 mm, the shoulder radius of the redrawing die is 1.5 times the plate thickness, and the clearance between the redrawing die and the punch is the plate thickness. It was processed under the condition that the clearance of the ironed portion was 55% of the original plate thickness. Water-based cooling and lubricants were not used in any of the processes, but were carried out in a dry manner.The presence or absence of breakage of the can wall, the condition of the outer surface of the can, neck-in workability, the electrolytic chromic acid treated steel sheet as the base and the resin layer coated Was evaluated for adhesion. In this composite processing, the molding is finished in the direction of the arrow, leaving the flange at the upper end of the can, the punch is retracted, and the can after the composite molding is taken out in the direction opposite to the arrow. Then, trim the upper end of the can,
By performing the flange processing, the resin-coated steel sheet according to the present invention has a high can height, a thin can wall thickness, and a can in a state in which the can lid can be tightly wound. Can wall breakage rate,
The condition of the outer surface of the can and the adhesion between the base steel sheet and the coated resin layer were evaluated according to the following criteria. 1) Rupture rate of can wall ：: 0%, ○: less than 1%, Δ: 1 to 5% 2) State of can outer surface (evaluated by flaw occurrence rate) ：: 0%, 、: less than 1%, Δ : 1 to 5% 3) Neck-in workability ：: good, ：: wrinkles and scratches are slight, no problem in practical use,
△: Practical problem 4) Processing adhesion of the coated resin layer (evaluated by the degree of peeling after neck-in processing) ◎: Good, ○: Slight peeling, but no practical problem,
Δ: Practical problem The results are shown in Tables 2 and 3.

(Example 2) Steel sheets D-2 and D- shown in Table 2
3, D-4 and D-5 were subjected to the same electrolytic chromic acid treatment as in Example 1 (metal chromium content: 75 mg / m ² , chromium content in hydrated chromium oxide: 13 mg / m ² ), and thermoplasticity was obtained. An original plate for resin lamination was used. These electrolytic chromic acid-treated steel sheets were heated to 240 ° C., and a biaxially stretched copolyester resin film comprising polyethylene terephthalate 88 mol% and polyethylene isophthalate 12 mol% (thickness: 12 μm) , Plane orientation coefficient: 0.12
6, melting point: 229 ° C.), a titanium oxide pigment was added to the outer surface of the can, and a biaxially stretched copolyester resin film (thickness: 12) having the same composition as the above and colored white
μm) were simultaneously laminated and immediately immersed in water and cooled. Then, after drying, on both sides about 50m of paraffin wax
g / m ² . Thereafter, molding was performed under the same conditions as in Example 1, and evaluation was performed in the same manner as in Example 1. Table 4 shows the results.

(Example 3) Steel plates D-2 and D- shown in Table 2
3, D-4 and D-5 were subjected to the same electrolytic chromic acid treatment as in Example 1 (the amount of chromium metal: 135 mg / m ² , the amount of chromium in chromium hydrated oxide: 15 mg / m ² ), and the thermoplasticity was obtained. An original plate for resin coating was used. These electrolytic chromic acid-treated steel sheets were heated to 235 ° C., and the upper layer was a copolymer polyester resin layer composed of 88 mol% of polyethylene terephthalate and 12 mol% of polyethylene isophthalate, and the lower layer was 94 mol of polyethylene terephthalate on the inner side of the can. %, A biaxially stretched copolyester resin film composed of 6% by mol of polyethylene isophthalate (thickness of upper layer: 15 μm, thickness of lower layer:
5 μm, melting point of upper layer: 229 ° C., melting point of lower layer: 226
° C, the plane orientation coefficient of the upper layer: 0.123, the plane orientation coefficient of the lower layer: 0.083), and a white colored biaxially stretched copolyester resin having the same composition as in Example 1 on the outer surface of the can. Films (thickness: 15 μm) were simultaneously laminated and immediately immersed in water and cooled. Then, after drying, about 50 mg / m ² of paraffin wax was applied to both surfaces. Thereafter, molding was performed under the same conditions as in Example 1, and evaluation was performed in the same manner as in Example 1. Table 5 shows the results.

(Example 4) Steel sheets D-2 and D- shown in Table 2
3, D-4 and D-5 were subjected to the same electrolytic chromic acid treatment as in Example 1 (metal chromium content: 95 mg / m ² , chromium content in hydrated chromium oxide: 15 mg / m ² ) An original plate for laminating a thermoplastic resin was used. These electrolytic chromic acid-treated steel sheets were heated to 240 ° C., and polyethylene terephthalate coated with an epoxy / phenol primer in a dry weight of 0.5 mg / m ² beforehand on the inner surface side of the can was prepared. 88 mol%, polyethylene isophthalate 12 mol%
A biaxially stretched copolyester resin film (thickness: 20 μm, plane orientation coefficient: 0.126, melting point: 2)
29 ° C.) On the surface to be the outer surface of the can, a titanium oxide pigment having the same composition as in Example 1 was added, and the biaxially stretched copolymerized polyester resin film colored white (thickness: 15 μm)
Were simultaneously immersed and cooled in water. Then, after drying, about 50 mg /
and m ² is applied. Thereafter, molding was performed under the same conditions as in Example 1, and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Tables 4, 5 and 6, wherein the thermoplastic resin-coated steel sheet of the present invention is dry-formed, has a high can height, and has a high can wall thickness. It turns out that it is suitable for.
Table 6 shows the results.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

[0036]

[Table 6]

[0037]

The resin-coated steel sheet for dry drawing and ironing cans according to the present invention is suitable for dry-forming ironing cans having a high can height and a thin can wall.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a resin-coated steel sheet for dry drawing and ironing cans according to the present invention.

FIG. 2 is a schematic view showing one embodiment of a process of dry-forming a can having a high can height and a thin can wall from a resin-coated steel plate for dry drawing and ironing cans according to the present invention.

FIG. 3 is a drawing and ironing process simultaneously performed from a resin-coated steel sheet for a dry drawing and ironing can according to the present invention, which is suitable for dry-forming a can having a high can height and a thin can wall. It is a schematic diagram of the partial cross section of compound processing.

FIG. 4 is a cross-sectional view of a can formed from a resin-coated steel plate for a dry drawing and ironing can according to the present invention.

FIG. 5 is a view showing an example of a can wall thickness profile of a can formed from a resin-coated steel plate for a dry drawing and ironing can according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel plate 2 Thermoplastic resin layer 3 Electrolytic chromic acid treatment film 4 High temperature volatile lubricant 5 Blank 6 Drawing can 7 Redrawing can 8 Redrawing and ironing can 9 Thin can wall 10 Can upper end 11 Residual flange 12 Trim can 13 Punch 14 Redrawing die 15 Ironing die 16 Ironing part 17 Wrinkle holder 18 Arrow 19 Can bottom 20 Neck L Distance between redrawing part and ironing part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ identification symbol FI C25D 11/38 301 C25D 11/38 301A (58) Field surveyed (Int.Cl. ⁶ , DB name) B21B 1/22 B21B 3 / 00 B32B 15/08 B21D 51/18 B21D 51/26

Claims (5)

(57) [Claims] 1. C content: 0.001 to 0.06%, Mn content: 0.05 to 0.50%, Al content: 0.015 to 0.13
%, Si content ≤ 0.05%, P content ≤ 0.03%, S content ≤ 0.0
A hot-rolled sheet having a balance of 03% and Fe and unavoidable impurities was subjected to pickling, cold rolling, continuous annealing, and a rolling reduction of 5 to 25.
%, The center line average roughness: 0.05 to 0.6 μm, the plate thickness: 0.15 to 0.30 mm, and then electrolytic chromic acid treatment. A method for producing a resin-coated steel sheet for dry drawing and ironing cans, which comprises coating a resin and applying a high-temperature volatile lubricant to the surface thereof. 2. C content: 0.001 to 0.06%, Mn content: 0.05 to 0.50%, Al content: 0.015 to 0.13
%, Si content ≤ 0.05%, P content ≤ 0.03%, S content ≤ 0.0
A hot-rolled sheet having a balance of 03% and Fe and unavoidable impurities is rolled at a rolling ratio of 5 to 25% after pickling, cold rolling, continuous annealing, and overaging, and has a center line average roughness of 0%. .05-
0.6 μm, plate thickness: 0.15 to 0.30 mm, then treated with electrolytic chromic acid, and then both sides have a thickness of 10 to 50
A method for producing a resin-coated steel sheet for dry drawing and ironing cans, characterized by coating a thermoplastic resin of μm and applying a high-temperature volatile lubricant to the surface thereof. 3. Content of C: 0.001 to 0.06%, Content of Mn: 0.05 to 0.50%, Content of Al: 0.015 to 0.13
%, Si content ≤ 0.05%, P content ≤ 0.03%, S content ≤ 0.0
Nb, Ti, and B, or 0.001 to 0.03% and 0.005%, respectively.
-0.05%, 0.001-0.01%, with the balance being F
e, and a hot-rolled sheet comprising unavoidable impurities is pickled, cold-rolled and continuously annealed, and then subjected to a rolling reduction of 5 to 25%, a center line average roughness of 0.05 to 0.6 μm, and a thickness of 0.15. ~ 0.30mm
And then subjected to electrolytic chromic acid treatment, and thereafter, both sides thereof are coated with a thermoplastic resin having a thickness of 10 to 50 μm, and a high-temperature volatile lubricant is applied to the surface thereof. Steel plate manufacturing method. 4. The method for producing a resin-coated steel sheet for a dry drawing and ironing can according to claim 1, wherein the thermoplastic resin is a crystalline polyester resin. 5. The dry drawing ironing can according to claim 1, wherein the thermoplastic resin layer is coated with an adhesive after the electrolytic chromic acid treatment and is adhered thereon. Manufacturing method of resin coated steel sheet.