WO2005110739A1 - Sn-PLATED STEEL SHEET COATED WITH RESIN, CAN USING THE SAME, AND METHOD FOR PRODUCING Sn-PLATED STEEL SHEET COATED WITH RESIN - Google Patents

Abstract

An Sn-plated steel sheet coated with a resin which comprises an Sn-plated steel sheet having an Sn plating layer and a silane coupling coating layer provided on the plating layer and, being laminated on the Sn-plated steel sheet through heat adhesion, a resin film having been subjected to a corona discharge treatment; a can using the Sn-plated steel sheet coated with a resin; and a method for producing the Sn-plated steel sheet coated with a resin. The can is manufactured by subjecting the Sn-plated steel sheet coated with a resin to any forming process of deep drawing, deep drawing followed by further stretching, deep drawing followed by further ironing, and deep drawing followed by a combination of stretching and ironing. The above Sn-plated steel sheet coated with a resin can retain excellent adhesiveness during forming even when it is subjected to a severe forming process.

Description

 Specification

 Resin-coated Sn-plated steel sheet, can using the same, and method for producing resin-coated Sn-plated steel sheet

 Technical field

 [0001] The present invention relates to a resin-coated Sn-plated steel sheet having excellent adhesion to a resin-coated layer, a can obtained by subjecting the resin-coated layer to severe forming such as squeezing, and a method for producing the resin-coated Sn-plated steel sheet. About.

 Background art

 [0002] In recent years, severe processing such as drawing of a steel sheet coated with resin, further stretching after drawing, further ironing after drawing, and further stretching and drawing combined with drawing are used. A canned product obtained by filling the contents in a canned-molded canned body with the can body and can bottom integrally formed, and winding the top plate around is commercially available. In these cans, excellent adhesiveness of the resin to the steel sheet is required so that the coating resin does not peel or break during and after these severe forming processes. For this reason, resin-coated steel sheets for these applications are those obtained by coating a chromate-treated steel sheet such as tin-free steel with a chromate film formed on the surface that has excellent workability with organic resins, and coating the resin with the resin. Retah.

 [0003] However, in a can using a resin-coated chromate-treated steel sheet, when fine holes or cracks reaching the steel sheet surface occur in the resin layer, the chromate-treated steel sheet has poor corrosion resistance. When filled with large contents, the steel sheet has the disadvantage that corrosion of the steel sheet progresses rapidly and drilling is easy. Therefore, an attempt was made to apply a resin-coated Sn-plated steel sheet obtained by coating a Sn-plated steel sheet, which shows excellent corrosion resistance when filled with contents with high acidity, with a resin. In particular, there is a need for a resin-coated Sn-plated steel sheet that can be applied to such severe processing applications as described above, which have poor work adhesion.

[0004] The inventors of the present invention have proposed a resin-coated Sn-plated steel sheet as a resin-coated Sn-plated steel sheet applicable to severe processing applications (for example, see Patent Document 1). The resin-coated Sn-plated steel sheet described in this publication is a no-reflow Sn-plated steel sheet or a reflow Sn-plated steel sheet. This is a resin-coated Sn-plated steel sheet obtained by laminating an organic resin film on a Sn-plated steel sheet in which a silane coupling agent coating layer is provided on the Sn plating layer of the steel sheet. This resin-coated Sn-plated steel sheet is characterized in that the adhesive strength of the organic resin film before forming into a can is 2 kg / l0 mm or more in T peel strength. However, when this resin-coated Sn-plated steel sheet is formed into a can by forming, especially when drawing into a can using the more stringent drawing and ironing together after drawing, there is no problem with forming. Potentially possible force During the molding process, the resin sometimes peeled off at the top of the can, and it was found that excellent adhesion of the resin to the Sn plating layer could not be stably obtained. It was also found that the adhesive strength of the organic resin film before forming into a can did not always accurately reflect the adhesiveness during and after forming.

[0005] In the present invention, a corona discharge-treated organic resin film is laminated on a no-reflow Sn-plated steel sheet or a Sn-plated steel sheet in which a silane coupling agent coating layer is provided on a Sn-plated layer of the reflow Sn-plated steel sheet. By doing so, it was found that a resin-coated Sn-plated steel sheet exhibiting stable adhesiveness during and after forming can be obtained. Further, it is disclosed that a corona discharge treatment is applied to a polypropylene resin film (see, for example, Patent Document 2). It is known that the adhesion to a substrate to be laminated is improved by performing a corona discharge treatment on an organic resin. However, by laminating the organic resin on a Sn-plated steel sheet that has poor process adhesion with the organic resin, and after drawing, it is stretched and ironed together to form a can that can withstand the severe processing applied to the can. In order to obtain adhesiveness, a silane coupling agent coating layer is provided on the Sn plating layer, and the corona discharge treated organic resin is coated so that the corona discharge treatment surface is in contact with the silane coupling agent coating layer. This made it possible for the first time to obtain cans from such resin-coated Sn-plated steel sheets with excellent corrosion resistance as substrates for stable processing.

 Patent Document 1: JP 2002-285354 A

 Patent Document 2: Japanese Patent No. 3352553

 Disclosure of the invention

 Problems to be solved by the invention

[0006] The present invention provides a resin-coated Sn having excellent work adhesion when subjected to severe molding. An object of the present invention is to provide a plated steel sheet, a can using the same, and a method for producing the resin-coated Sn-coated steel sheet.

 Means to solve the problem

[0007] The resin-coated Sn-plated steel sheet of the present invention is obtained by coating at least one surface of an Sn-plated steel sheet obtained by forming a silane coupling agent coating layer on a Sn plating layer with an organic resin film subjected to a corona discharge treatment. Resin-coated Sn-plated steel sheet (Claim 1), comprising a Sn-plated steel sheet (No-reflow Sn-plated steel sheet) with a Sn-plated layer formed on a Sn-plated steel sheet 1S steel sheet, or a steel sheet and a Sn-plated layer. Sn-plated steel sheet (reflow Sn-plated steel sheet) in which a Sn-Fe alloy layer is formed in between (Claim 2) and the amount of the silane coupling agent applied is 1 to 50 mg / m ² in terms of Si amount. (Claim 3), and the corona discharge treatment was performed under the conditions of voltage: 200V, current: 0.2-8A / 25cm (claim 4). 1) Resin-coated Sn-plated steel sheet of any one of 4), drawing ratio: 1.6 4) The peel strength of the resin film on the side wall of the cup after forming it into a drawn cup with a diameter of 96 mm and a height of 42 mm by drawing at least 0.05 kg / 15 mm (Claim 5) Features.

 [0008] Further, the can of the present invention can be obtained by drawing the resin-coated Sn-plated steel sheet according to any one of claims 15 to 15 (claim 6), or can be further stretched after drawing. Cans (Claim 7), cans that have been drawn or further ironed after drawing (Claim 8), or cans that have been drawn and processed using both stretching and ironing (Claim 8) 9).

Further, the method for producing a resin-coated Sn-plated steel sheet of the present invention comprises forming a Sn-plated layer on at least one side of the steel sheet, applying a silane coupling agent on the Sn-plated layer, drying the Sn-plated layer, and then drying. A method for producing a resin-coated Sn-plated steel sheet, comprising laminating an organic resin film that has been subjected to corona discharge treatment such that the corona discharge treatment surface is in contact with the agent application layer, or at least one side of the steel sheet has Sn A Sn-Fe alloy layer is formed between the steel sheet and the Sn plating layer by forming a plating layer, then heating to a temperature equal to or higher than the melting temperature of Sn, and then quenching, and then applying a silane coupling agent on the Sn plating layer. After drying, an organic resin film that has been subjected to corona discharge treatment is laminated on the silane coupling agent coating layer so that the corona discharge treatment surface is in contact with the silane coupling agent coating layer. Of the coated Sn-plated steel sheet It is a manufacturing method.

 Brief Description of Drawings

 FIG. 1 is a plan view showing the shape of a test piece for measuring the S-peel strength.

 [FIG. 2] FIG. 2 is a plan view showing a place where a cut is made in a resin surface of a test piece for S peel strength measurement.

 [FIG. 3] FIG. 3 is a plan view showing locations where scores are put on a specimen for S peel strength measurement.

FIG. 4 is a cross-sectional view of a part of a test piece showing a shape of a scored portion.

 FIG. 5 is a schematic view of a specimen holder. For the sign, 1 is the specimen, la is one end of the specimen, lb is the other end of the specimen, 2 is the cut, 3 is the score, 4 is the specimen holder, 4a Indicates a specimen insertion part, and 4b indicates an upper part of a specimen holder.

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described in detail.

 As the steel sheet used for the resin-coated Sn-plated steel sheet of the present invention, a cold rolled steel sheet obtained by cold rolling a normal aluminum killed steel sheet, annealing and then temper rolling, or further cold rolling after annealing The strength of the cold-rolled steel sheet, which has been increased in strength by the application, is selectively used depending on the application. These cold-rolled steel sheets are electrolytically degreased and pickled, and then a Sn plating layer is formed on the steel sheets to obtain Sn-plated steel sheets. As the Sn-plated steel sheet, a Sn-plated steel sheet (No-reflow Sn-plated steel sheet) with Sn plated thereon using a well-known porstan bath or halogen bath, and after Sn was plated, was heated to the melting temperature of Sn or higher. There is a Sn-plated steel sheet (reflow Sn-plated steel sheet) in which a Sn—Fe alloy layer is formed between Sn plating layers by rapid cooling afterwards. In addition to these Sn-plated steel sheets, Ni is electroplated, and Ni is plated on the steel as it is or heated after Ni plating to diffuse Ni into the steel to form a Ni-Fe alloy layer. For example, an island-shaped Sn-plated steel sheet having an island-shaped Sn layer formed thereon may be used by, for example, heating the metal to a temperature equal to or higher than the melting temperature of Sn and then rapidly cooling.

[0012] Sn plating amount of no reflow Sn-plated steel sheet of the matte is Shi preferred in the range of 0. 1- 10g / m ² in terms of corrosion resistance and economy les. In a glossy reflow Sn-plated steel sheet, a Sn-Fe alloy layer is formed between the Sn plating layer and the steel sheet, If metallic Sn remains on the surface of the plated steel sheet, the total Sn plating amount must be within the range of 11 lOg / m. On the surface of the plated steel sheet without leaving the metal Sn, if the Sn- Fe alloy layer consisting of only a layer of the surface layer, the total Sn plating amount be in the range of 0. 1- 10g / m ² preferable.

[0013] In the case of island-like Sn-plated steel sheet, the amount of Ni plating to be formed on the steel sheet before being subjected to Sn plating 0. 005-0. Lg / m ^2, the amount of Sn plating is formed on the upper layer 0 It is preferably in the range of 1—1.5 g / m ² . After forming each plating layer with such a plating amount, or after plating Ni with the above-mentioned plating amount and performing a diffusion heat treatment, and then plating Sn with the above-mentioned plating amount, the temperature is raised to the melting temperature of Sn or higher. By heating, an island-shaped Sn-plated steel sheet having Sn dispersed in the surface and present on the surface is obtained.

[0014] A silane coupling agent is applied to the surface of the Sn-plated steel sheet obtained as described above and dried. As the silane coupling agent, there are various types such as a bull type, an acrylic type, an epoxy type, an amino type, a mercapto type, and a black pill type. In the present invention, it is preferable to use an amino silane coupling agent. . As an amino-based silane coupling agent, aminopropyltrimethoxysilane, aminopropylmethylethoxysilane, aminopropyltriethoxysilane, phenylaminopropyltrimethoxysilane and the like can be used. A 5-200 g / L aqueous solution of these silane coupling agents is applied to the Sn-plated steel sheet and dried. Known application methods can be applied as the application method. For example, any of an immersion method, a roll coating method, a method of squeezing the excess using a squeezing roll after immersion, a spray method, an electrolytic treatment method, and the like can be applied. The amount of the coating film after drying is preferably 50 mg / m ² in terms of the amount of Si measured by the fluorescent X-ray method. When the amount of Si is less than lmg / m ² , the processing adhesive strength of the resin film laminated on the silane coupling agent applied layer becomes poor. On the other hand, even if the amount of Si exceeds 50 mg / m ² , the processing adhesive strength of the resin film becomes insufficient, and it becomes uneconomical. Thus, a Sn-plated steel sheet used for the resin-coated Sn-plated steel sheet of the present invention is obtained.

[0015] The resin-coated Sn-plated steel sheet of the present invention is obtained by applying an organic resin film obtained by subjecting one or both sides of the Sn-plated steel sheet obtained as described above to a corona discharge treatment to a silane coupling agent. It is obtained by laminating so as to be in contact with the coating layer. Organic tree Examples of the fat film include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, ethylene terephthalate 'ethylene isophthalate copolymer, butylene terephthalate and butylene isophthalate copolymer, and two types of these polyester resins. Blends of the above, polyethylene, polypropylene, ethylene / propylene copolymers, and those modified with maleic acid, polyolefin resins such as ethylene • butyl acetate copolymer, ethylene'acrylic acid copolymer, 6_ nylon, A single-layer resin filter composed of polyamide resin such as 6,6_ nylon and 6,10-nylon, polycarbonate, polymethylpentene, and a blend of the above polyester resin and ionomer. Arm, further can be used as the resin film Lum double layer consisting of two or more kinds of these resins. The thickness of the resin film is 10 to 100 zm in view of the ease of film lamination work, the adhesive strength of the resin film on the formed body (can) after forming the resin-coated Sn-plated steel sheet, corrosion resistance, and economy. It is preferable that

[0016] These resin films are obtained by heating and melting resin pellets, extruding them from a T-die of an extruder, and forming a film having a desired thickness on the Sn-plated steel sheet by a heat bonding method. Adhesive lamination is used. The thermal bonding method is a method in which a resin film is brought into contact with a Sn-plated steel sheet heated to a temperature range in which the resin adheres, sandwiched between a pair of pressure rolls, and pressed to make pressure contact. By using a resin film that is formed without being applied, thermal bonding can be performed at a temperature considerably lower than the melting temperature of Sn. When laminating resin films formed by stretching in the uniaxial or biaxial directions, heat setting after stretching must be performed at a temperature significantly lower than the melting temperature of Sn, or Unless the resin is heated to a high temperature, good working adhesion strength to the Sn-plated steel sheet cannot be obtained. Therefore, when using a resin whose melting temperature is higher than the melting temperature of Sn, it becomes difficult to heat bond.

[0017] In the present invention, in particular, even when subjected to severe forming such as forming into a can by performing a combination of stretching and ironing after drawing, stable and excellent processing adhesion of the resin film. In order to obtain a resin film, a resin film obtained as described above, which has been subjected to corona discharge treatment on the surface in contact with the Sn-plated steel plate, is used. The corona discharge treatment is performed under the following conditions: voltage: 200 V, current: 0.2 to 8 A / 25 cm. If the current is less than 0.2A / 25cm, The effect of the Rona discharge treatment is not exhibited. On the other hand, if the current exceeds 8 A / 25 cm, the discharge current becomes excessive, and wrinkles and swelling occur in the resin film, which is not preferable. A more preferable range of the laser current is 115 A / 25 cm. The corona discharge-treated side of the resin film is brought into contact with the surface of the Sn-plated steel sheet to which the silane coupling agent has been applied, and is thermally bonded as described above. Even in this case, stable and excellent processing adhesion of the resin film can be obtained.

 [0018] Conventionally, the peel strength, that is, the adhesive strength of the resin film to the Sn-plated steel sheet has been evaluated by measuring the T-peel strength in a state of a flat plate before processing. However, the T-peel strength measured in the state of a flat plate is especially important during and after processing when severe forming such as forming into a can by applying a combination of stretching and ironing after drawing is applied. It was found that the later bonding strength, that is, the processing bonding strength was not always accurately reflected. Therefore, in the present invention, the resin-coated Sn-plated steel sheet is drawn and formed into a cup, and a cup side wall test piece is cut out. The peel strength of the resin film of the test piece is referred to as a processing adhesive strength (hereinafter referred to as S-peel strength). ) To evaluate.

The method for measuring the S-peel strength is described below. A 154 mm blank was punched out from the resin-coated Sn-plated steel sheet of the present invention obtained as described above, and subjected to a one-step drawing process at a drawing ratio of 1.64 to obtain a drawing cup having a diameter of 96 mm and a height of 42 mm. Mold into From this cup, the side wall is cut out to a size of 30 mm in the height direction of the cup and 120 mm in the circumferential direction of the cup, bent back to a flat plate shape, and then a T-shaped specimen 1 shown in Fig. 1 is punched out. Next, as shown in FIG. 2, a cut 2 is made in the resin film on one side la of the specimen 1 on the side opposite to the adhesive strength measurement surface using a cutter knife so as to reach the Sn-plated steel sheet surface. Next, as shown in FIGS. 3 and 4, a score 3 is inserted from the side opposite to the adhesive strength measurement surface using a score die set, and then the score portion is bent to cut the Sn-plated steel sheet. At this time, on the adhesion strength measurement surface, the resin film remains connected to both sides of the cut Sn-plated steel sheet without being cut. Next, as shown in FIG. 5, one end la is inserted into the specimen insertion portion 4a of the specimen holder 4, and the specimen 1 is fixed to the specimen holder 4, and then the upper part 4b of the specimen holder 4 and the specimen are fixed. The other end lb of piece 1 was sandwiched between the chucks of a Tensilon tensile tester and pulled, and the resin film was forcibly peeled from the Sn-plated steel sheet to measure the tensile strength. Evaluate the processing adhesive strength.

 [0020] The S-peel strength measured as described above is preferably 0.05 kg / 15 mm or more. When the S-peel strength is less than 0.05 kg / 15 mm, it is stable and good especially when severe forming such as drawing and ironing is used in combination with drawing and ironing to form a can. High working adhesion strength cannot be obtained.

 When the resin-coated Sn-plated steel sheet of the present invention is formed into a drawn can, a blank punched from a resin-coated Sn-plated steel sheet having resin laminated on one or both sides is formed into a cup shape using a drawing die. Draw. To increase the height of the side wall by reducing the diameter, redraw using a smaller drawing die than the previous stage. Drawing is usually performed with one or two stages of drawing calorie, and is applied to cans with relatively large diameters and low side walls.

 When the resin-coated Sn-plated steel sheet of the present invention is drawn and then stretched to form a can, a blank punched out of a resin-coated Sn-plated steel sheet having resin laminated on one or both sides is drawn with a drawing die. And drawn into a cup shape using. Next, using a multi-stage drawing die, the side wall height is increased while reducing the diameter sequentially.In stretch processing, when the cup is pressed by a processing punch and enters and exits the drawing die and wrinkle suppressing jig. The side wall is bent and bent back, and the side wall portion is stretched and thinned to be drawn. It is applied to cans with relatively small can diameter and high side wall height.

 When the resin-coated Sn-plated steel sheet of the present invention is drawn and then ironed to form a can, a blank punched from a resin-coated Sn-plated steel sheet having resin laminated on one side or both sides is formed in one step or The cup is drawn in a cup shape using a plurality of drawing dies. Next, using one or more steps of ironing dies, set the side wall thickness smaller than the side wall thickness of the wrench. Forcibly push the side wall into the clearance between the ironing die and the punch to reduce the thickness of the side wall. Raise the quality and apply the ironing process. Therefore, the present invention is applied to a can having a relatively small can diameter, a high side wall height and a small side wall thickness. When a resin-coated Sn-plated steel sheet with resin laminated only on one side is ironed with the non-resin-coated surface facing the outside of the can, the Sn-plated layer is rubbed by ironing dies and becomes a mirror surface, resulting in a beautiful surface gloss. can get.

In the case where the resin-coated Sn-plated steel sheet of the present invention is drawn and then formed into a can by using both stretching and ironing, resin-coated Sn having a resin laminated on one side or both sides is used. A blank is punched from a plated steel sheet and drawn into a cup shape using one or more stages of drawing dies. Next, in the same way as in normal stretching, using a multi-stage drawing die, the height of the side wall is increased while the diameter is reduced gradually, but the clearance between the die and the punch is cup-shaped like the ironing die in ironing. By setting the thickness to be smaller than the side wall thickness of the side wall, the side wall is bent and unbent, and simultaneously ironed, and the side wall is stretched and thinned to draw and iron. In this processing, a beautiful surface gloss can be obtained even when a resin-coated Sn-plated steel sheet in which a resin is laminated on only one side is used. Example

 Hereinafter, the present invention will be described in more detail with reference to Examples.

 [Preparation of Sn plated steel sheet]

 The cold-rolled steel sheet having the thickness and temper shown in Table 1 was electrolytically degreased in an aqueous alkaline solution, washed with water, then with sulfuric acid, washed with water, and then in a known ferrostan bath under the conditions shown in Table 1. The Sn-Fe alloy layer was formed between the steel sheet and the Sn plating layer by performing a reflow treatment after forming the Sn plating layer or forming the Sn plating layer. Next, using a treatment bath shown in Table 1, a 5-200 g / L aqueous solution of the silane coupling agent shown in Table 1 was applied by an immersion method so as to have an application amount shown in Table 1, and dried. A silane coupling agent coating layer was formed on the plating. As a comparative material, a tin-free steel was prepared by subjecting a cold-rolled steel sheet to electrolytic chromic acid treatment to form two layers, a Cr plating layer and a Cr hydrated oxide layer, as shown in Sample No. 10.

[Table 1]

Test steel plate Plating amount Rif I> -Cr hydrated oxide silane? ;;

Plate thickness Tenha "" Type Adhesion amount (As Cr Type of treatment solution Adhesion amount (mm) (g / m ^s ) mg / m ² ) (As Si

mg / m ² )

1 0.18 D -6 Sn 7 Yes ― Marauder- 903 10 Present invention

20.18 DR-6 Sn 5 Yes ― recitation -903 8 Present invention

3 0.24 T-3CA Sn 3 None ― KBM-903 17 pcs.

4 0.24 T-3CA Sn 10 Yes-903

5 0.24 T-3CA Sn 7 Yes-KBM-903 15 Present invention

6 0.18 DR-6 Sn 3 ― KBM-603 20 The present invention

7 0.18 DR-6 Sn 8 Yes ― KBM-903 8 Present invention

8 0.i8 DR-6 Sn 6 Yes ― KBM-603 2 The present invention

9 0.18 DR-6 Sn 5 ― KBM-903 15 Comparative example

10 0. 18 DR-6 Cr 0.12 18 ― ― Comparative example Note) KBM903: Aminopropyl trimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd.

KBM603: Aminopropyltriethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd. 2]

Corner discharge treatment

 Fee

 Turn voltage: hiring

 Current value

 (A)

1 8

2 0.2 Bookshelf

3 1 The present invention

4 4 The present invention

5 4 The present invention

6 5 The present invention

7 4 The present invention

8 3 The present invention

9-Comparative example

10-Comparative example

[Preparation of resin-coated Sn-plated steel sheet]

One side of tin-plated steel and tin-free steel shown in Table 1 was subjected to corona discharge treatment on one side under the conditions shown in Table 2. Thickness: 28 μm non-oriented transparent ethylene terephthalate. Ethylene isophthalate Copolymer (indicated by PETI) two-layer film (upper layer force SPETI15 (thickness: 12 μm), lower layer PETI5 (thickness: 16 / im), numbers indicate mol% of ethylene isophthalate, PETI5 side White non-oriented two-layer film containing the same ethylene terephthalate 'ethylene isophthalate copolymer and 20% by weight of titanium-based white pigment on the other side (top layer SPETI15 (thickness: 5 μm) and the lower layer force ^ ΡΕΤΙ5 (thickness: 11 μm)) by heat bonding at 225 ° C using a thermal bonding method, and then laminating them. A resin-coated tin-free steel indicated by No. 10 was produced. As a comparative material, a resin film was laminated without corona discharge treatment shown in Sample No. 9. A coated Sn-plated steel sheet was also prepared.

[Preparation of Specimen for S Peel Strength Measurement]

 From the resin-coated Sn-plated steel sheet and the resin-coated tin-free steel shown in Table 1, the transparent resin film-coated surface is on the inside of the cup, and a one-step drawing process with a drawing ratio of 1.64 is performed as described above. Was performed to prepare a squeezing cup, and a test piece for measuring the S-peel strength was prepared as described above so that the surface coated with the transparent resin film was the measurement surface. The S-peel strength was then measured using Tensilon as described above. Table 3 shows the results.

 [Table 3]

[Formation of drawn can]

Sample No. 11 shown in Table 1 After punching a resin-coated tin-free steel into a blank with a diameter of 112 mm, the transparent resin film-coated surface is placed on the inside of the cup, and the drawing is performed at a drawing ratio of 1.50. : Redrawing was performed in 2.1 to form a drawing can with a can diameter of 53 mm. Next, the upper part of the can was trimmed by a known method, and subjected to neck inca glue and flange glue. After forming 1,000 drawn cans in this way, the presence or absence of peeling of the resin film was visually observed, and the occurrence rate of molded cans in which peeling was recognized was evaluated in%. Table 4 shows the results.

[Formation of a can formed by stretching after drawing]

 After punching a resin-coated tin-plated steel plate of sample numbers 1-2 and 6-9 and a resin-coated tin-free steel of sample number 10 shown in Table 1 into a blank of 187 mm in diameter, the transparent resin film-coated surface is the inside of the cup. Then, drawing was performed at a drawing ratio of 1.70 to form a cup. Next, the primary redrawing ratio: 1.29, the secondary redrawing ratio: 1.24, the tertiary redrawing ratio: 1.20, the radius of curvature of the redrawing die shoulder: 0.4 mm, the wrinkle suppressing load: Stretching was performed in multiple stages under the condition of 58N, and formed into a stretched can with a can diameter of 66mm. Next, the upper portion of the can was trimmed by a known method, and neck-in processing and flange processing were performed. After forming 1000 stretched cans in this way, the presence or absence of peeling of the resin film was visually observed, and the occurrence rate of molded cans in which peeling was observed was evaluated in%. Table 4 shows the results.

 [0033] [Forming of a can by drawing and then ironing]

 After punching a resin-coated tin-plated steel sheet and resin-coated tin-free steel of sample numbers 3-5 shown in Table 2 into a blank with a diameter of 140 mm, the transparent resin film-coated surface was on the inner side of the die. Drawing ratio: drawing at a drawing ratio of 1.63, and then redrawing at a drawing ratio of 1.30 to form a cup with a can diameter of 66 mm. Next, three-stage ironing (total ironing rate: 65%) was performed, and a can with a can diameter of 66 mm was formed. Next, the upper portion of the can was trimmed by a known method, and a neck inca glue and a frangible glue were applied. After forming 1000 stretched cans in this way, the presence or absence of peeling of the resin film was visually observed, and the occurrence rate of molded cans in which peeling was observed was evaluated in%. Table 4 shows the results.

 [Forming of a can formed by using a combination of stretching and ironing after drawing]

Resin-coated Sn-plated steel sheets of Nos. 1, 2, and 6-9 shown in Table 1 and sample numbers Ten pieces of resin-coated tin-free steel were punched into a blank having a diameter of 160 mm, and were drawn into a cup having a can diameter of 100 mm so that the transparent resin film-coated surface was on the inner side of the cup. Next, a redrawing cup having a can diameter of 80 mm was obtained by redrawing. Further, the redrawn cup was used in combination with stretching and ironing to make a can with a can diameter of 65 mm. In the case of using both stretching and ironing, the distance between the redrawing part at the upper end of the can and the ironing part is 20 mm, the radius of curvature of the redrawing die shoulder is 1.5 times the sheet thickness, and the redrawing is performed. The test was performed under the condition that the clearance between the die and punch was 1.0 times the sheet thickness and the clearance of the ironed part was 0.5 times the sheet thickness. Subsequently, the upper part of the can was trimmed by a known method, and subjected to neck inker knitting and flange processing. After forming 300 stretched cans in this way, the presence or absence of peeling of the resin film was visually observed, and the occurrence rate of molded cans in which peeling was observed was evaluated in%. Table 4 shows the results.

[Table 4]

Occurrence rate of test resin exfoliation (%)

 Fee

 Turn

 No. Drawing After drawing After drawing

 Stretch processing Ironing processing Strike processing

 Toseki

 Together with

1 0 0-0 The present invention

2 0 0-0.2 The present invention

3 ― ― 0 ― The present invention

4 ― 0 ― The present invention

5 ― 0 ― The present invention

6 0-0 The present invention

7 0 0-0 The present invention

8 0 0-0.1 The present invention

9 0 0 ― 3.3 Comparative example

Comparative Example As shown in Table 4, the resin-coated Sn-plated steel sheet of the present invention obtained by laminating a resin film subjected to a corona discharge treatment on a Sn-plated steel sheet provided with a silane coupling coating layer, Compared to a resin-coated Sn-plated steel sheet that is formed by laminating a resin film on a Sn-plated steel sheet provided with a silane coupling coating layer without discharge treatment, the resin film has better work adhesion to the Sn-plated steel sheet. This is consistent with the S-peel strength shown in Table 3, that is, the result of the adhesiveness after processing by one-step drawing. As described above, the resin-coated Sn-plated steel sheet of the present invention is processed by using a combination of drawing at multiple stages, styling after drawing, ironing after drawing, stretching after drawing, and ironing. When subjected to demanding machining, as well as in resin-coated tin-free steel, stable and excellent machining Shows adhesion.

Industrial applicability

 The resin-coated Sn-plated steel sheet of the present invention is formed by laminating a resin film subjected to corona discharge treatment to a Sn-plated steel sheet having a silane coupling coating layer provided on a Sn plating layer by heat bonding, and drawing. In addition, the resin film does not peel even after further stretching after drawing and further ironing after drawing, and shows stable and excellent work adhesion. In addition, even when a more severe drawing process is followed by a process using both stretching and ironing, the resin film does not peel off.Sn plating with a silane coupling coating layer on the Sn plating layer It shows stable and excellent work adhesion compared to resin-coated Sn-plated steel sheets obtained by thermally bonding a resin film that is not subjected to corona discharge treatment to a steel sheet.

Claims

The scope of the claims  [I] A resin-coated Sn-plated steel sheet in which at least one side of an Sn-plated steel sheet having a silane coupling agent coating layer formed on a Sn-plated layer is coated with an organic resin film subjected to a corona discharge treatment.  [2] Strength of Sn-plated steel sheet Sn-plated steel sheet with no Sn-plated layer formed on the steel sheet (No-flow Sn-plated steel sheet), or Sn-Fe alloy layer formed between steel sheet and Sn-plated layer The resin-coated Sn-plated steel sheet according to claim 1, which is a Sn-plated steel sheet (reflow Sn-plated steel sheet). [3] The resin-coated Sn-plated steel sheet according to claim 1 or 2, wherein the application amount force of the silane coupling agent is 1 to 50 mg / m ² in terms of Si amount. [4] The resin-coated Sn-plated steel sheet according to any one of claims 13 to 13, wherein the corona discharge treatment is performed under the conditions of voltage: 200V, current: 0.2 to 8A / 25cm. [5] The peel strength of the resin film on the side wall of the cup after forming it into a drawing cup with a diameter of 96 mm and a height of 42 mm by single-step drawing with a drawing ratio of 1.64 is at least 0.05 kg / 15 mm. 15. The resin-coated Sn-plated steel sheet according to any one of claims 14 to 14, characterized in that: [6] A can obtained by drawing the resin-coated Sn-plated steel sheet according to any one of claims 15 to 15. [7] A can obtained by subjecting the resin-coated Sn-plated steel sheet according to any one of claims 15 to 15 to drawing and further stretching.  [8] A can obtained by drawing the resin-coated Sn-plated steel sheet according to any one of claims 11 to 5 and then ironing it.  [9] A can which is obtained by drawing the resin-coated Sn-plated steel sheet according to any one of claims 11 to 5, followed by drawing and ironing. [10] A Sn plating layer is formed on at least one side of the steel sheet, and then a silane coupling agent is applied on the Sn plating layer and dried. A method for producing a resin-coated Sn-plated steel sheet, comprising laminating an organic resin film subjected to a discharge treatment. [II] A Sn-plated layer is formed on at least one side of the steel sheet, then heated to a temperature equal to or higher than the melting temperature of Sn and rapidly cooled to form a Sn-Fe alloy layer between the steel sheet and the Sn-plated layer. After applying a silane coupling agent on the Sn plating layer and drying, an organic resin film that has been subjected to corona discharge treatment is laminated on the silane coupling agent application layer so that the corona discharge treatment surface is in contact with the film. A method for producing a resin-coated Sn-plated steel sheet.