JPH05131607A - Manufacture for laminated steel sheet for three-piece can - Google Patents

Abstract

PURPOSE:To provide a manufacture of a laminated steel sheet possessing a stripy multi-layer structural organic film on a specific position of the surface of the steel sheet for drastic rationalization of a painting and printing processes of a three-piece can. CONSTITUTION:At the time of lamination of an organic resin film on the surface of a steel sheet in a stripy state, after lamination of a wide film to the whole surface of the steel sheet, continuing cuts are put in the laminated film layer, a necessary part only is left behind on the surface of the steel sheet and an unnecessary part is removed by peeling, through which a wide steel sheet where a large number of stripes are laminated is obtained. If circumstances require, perforationlike cuts for separation of a laminated part and nonlaminated part from each other are performed beforehand into the film to be laminated, which can be made into an assistance for film cutting. Printing or the others indicating contents are performed beforehand on the film to be laminated, a small blank (rectangular steel sheet having dimensions corresponding to one can) posessing unpainted parts on both ends is cut off and used for manufacturing of a welding can.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic laminated steel sheet for metal cans, in particular, a cylindrical can body is formed by a method such as electric resistance welding or organic bonding, and the top and bottom lid is wound to fill the contents. The present invention relates to a so-called organic laminated steel sheet for a three-piece can.

[0002]

As is well known, as a method for manufacturing a metal can,
A two-piece can in which the can bottom and the can body are formed by drawing or drawing and ironing is integrated, and a cylindrical can body is formed by a method such as electric resistance welding or organic bonding, and the top and bottom lid is wound. A three-piece can that is tightened and molded is known.

As a material for a three-piece can, a tin-based material in which a steel plate is tin-plated and chromated, a nickel-plated material in which a steel plate is nickel-plated and chromated, and a steel plate made of metal chromium and hydrated chromium oxide are used. Tin-free steel materials and other materials with a two-layer coating are used. In most cases, these materials are coated on the inside from the viewpoint of content retention (corrosion resistance), and a trademark design for content display is printed on the outside of the can.

Such inner surface coating and outer surface printing are carried out by cutting the above-mentioned material for a three-piece can into a cutting plate, and then, on the cutting plate coating line, an inner surface coating (first time) and an outer surface printing base white coat (second time). ), And the outer surface printing (third time) is performed three times. For applications that require a high degree of corrosion resistance, it is necessary to coat the inner surface twice, and in the case of multi-color printing of more than five colors on the outer surface, it may be necessary to print twice, resulting in four passes. Paint printing on the inner and outer surfaces may be performed by a plate or a 5-pass plate. Then, it is necessary to heat the cut plate in the baking oven for each passing of the plate.

In order to rationalize such a coating and printing process,
It is expected that the so-called coil coating method will consistently and continuously perform internal coating, white coating for external printing, and even external printing, but if a metal base is used as a base, printing accuracy can be achieved. It is difficult and has not been put to practical use. The portion of the steel plate that has been painted and printed by a large number of cutting plate line passing is left unpainted, and after being cut to a size corresponding to the can size, it is rolled into a cylindrical shape. , And welded to form a three-piece can body.

[0006]

However, such a complicated coating and printing process for a three-piece can has (1) poor productivity,
(2) In-process period is long, (3) Many manpower is required,
It has many problems such as (4) difficulty in improving the appearance of printed finish, (5) difficulty in using ultra-thin material, etc., and has been a cause of reducing the competitiveness of the three-piece can.

The present invention proposes a method for making it possible to perform painting / printing in the form of a coil continuously by one pass in order to drastically revolutionize this complicated painting / printing process. It is an object of the present invention to solve the above five problems at once by continuously performing coating and printing in a coil shape, and to provide a manufacturing method with high flexibility and excellent quality and productivity. ..

[0008]

The basic technical idea of the present invention is to apply a printing / printing process performed on a cut plate by continuously laminating a printed film of a trademark design on a steel plate in a stripe shape. It is to obtain the same function as to serialize. The surface-treated steel sheet used in the present invention is not particularly limited, but a metal such as tin, nickel, chromium, or aluminum, an alloy thereof or an oxide thereof is plated, and the outermost surface ensures adhesion with an organic substance. Therefore, chromate treatment or phosphate treatment is performed.

These surface-treated steel sheets are generally 70
Manufactured with a board width of 0 to 1000 mm, 4 to 4 per board width
A blank equivalent to 6 cans (rectangular steel plate cut into the size of 1 can) has a size that can be taken. As described above, since each blank is rolled into a cylindrical shape and then welded, the portion to be welded needs to be left unpainted. For example, to make a cylinder with a can diameter of 52 mm,
A blank length of 163.8 mm is required, including a lap margin (overlap portion for welding) of 0.5 mm, and both ends are 2 mm.
It is necessary to make it unpainted. Therefore, when laminating films, a steel plate is generally required to have a required size (1
63.8 mm) width is slit into a strip shape, and a pre-prepared film of 159.8 mm width is placed on both ends of the steel plate 2 mm.
Although a method of laminating and leaving is used, this method technically provides a reliable manufacturing method, but it is necessary to cut out the steel plate and the film in advance to the required dimensions, and since it is manufactured one by one, productivity is improved. Is unsatisfactory in terms of.

According to the present invention, it is possible to realize a coating / printing process with excellent productivity by laminating multiple strips of films on the entire surface in the width direction without preliminarily slitting the steel plate into strips. .. Two types of films are used in the present invention. The first is a film for the outer surface of a can, and this film constitutes an important technical factor of the present invention.

It is important that the film for the outer surface of the can is preprinted with a trademark design for displaying the contents, and is also provided with a non-printed portion which is cut and removed as an unnecessary portion after lamination. As shown in the above example, it consists of a printed part with a width of 159.8 mm and a non-printed part with a width of 4 mm, and there are 6 striped printed parts within the film total width of 958.8 mm. After the adhesive is hardened, the non-printed portion having a width of 4 mm is continuously peeled and removed from the system. Therefore, it is important that the adhesive is not applied to the portion removed after the film is laminated, and the adhesive is applied in stripes only on the previously printed portion.

As described above, the film for the outer surface of the can used in the present invention has an adhesive layer, a printing layer and a carrier film layer as its basic constitution, but various other applied forms can be adopted. For example, a four-layer structure of adhesive layer / printing ink layer / carrier film layer / top coat layer or adhesive resin film layer / printing ink layer / carrier film layer / top coat layer can be exemplified. In this case, the top coat layer is provided for the purpose of improving surface gloss and improving surface lubrication. Further, a three-layer structure of carrier film layer / printing ink layer / top coat layer is also possible, and in this case, the carrier film layer itself needs to have thermal adhesiveness.

Polyolefin films such as polyethylene and polypropylene, polyamide or polyester films, and the like are candidates for the carrier film, but polyester films are most preferable from the viewpoint of heat resistance. The procedure for producing a film having a four-layer structure is exemplified as follows. For example, as the saturated polyester resin used in the present invention, a polyethylene terephthalate homopolymer, a copolyester resin, or a resin film having a stretched and oriented structure by a blend thereof is preferably used. A thermosetting polyester resin containing silicon as a top coat layer is applied to one surface of this film,
It is dried at a low temperature for a short time so that film shrinkage does not occur. The added amount of silicon lubricant has a static friction coefficient of 0.2.
It is important to make the following adjustments. afterwards,
Using a printing ink with polyurethane resin as the main binder, gravure printing of 5 colors is performed on the opposite side of the top coat layer, and a polyurethane adhesive containing a curing agent is applied and dried on the final stand to form a 4-layer structure. The production of the film having can be carried out.

Another type of film is a film for the inner surface of a can, and a colorless and transparent film is mainly used. In this case as well, it is composed of a portion to be laminated on the steel plate and a portion to be cut and removed after the lamination, and since it is not clear in appearance because no printing design is applied, it is laminated in the same manner as the can outer surface film. Polyolefin films such as polyethylene and polypropylene, polyamide films, polyester films, and the like are candidates for the resin, but polyester films are most preferable from the viewpoints of heat resistance and content protection.

The manufacturing method of the present invention will be described in detail below. First, the surface-treated steel sheet used in the present invention is supplied as a coil product, and if necessary, a thermosetting paint or the like is applied in stripes at a predetermined film laminating position and baked, and then heated to a temperature necessary for film laminating or The temperature is controlled by cooling. As a heating method, hot air heating, radiant heating, or the like can be used, but from the viewpoint of temperature controllability, electric heating / induction heating is preferable, and heating is performed in a temperature range of 100 to 250 ° C. by an adhesive method.

As a procedure for laminating the film on the surface of the steel sheet which has reached a predetermined temperature, a wide film having a striped print portion is unwound and laminated on the entire surface of the steel sheet at a speed equivalent to the passing speed. At that time, if the surface of the steel sheet is previously coated with a thermosetting coating in a striped pattern, accurate positioning is required so that the striped printed portion of the film overlaps the striped thermosetting coating. .. In addition, it is necessary to ensure the length accuracy so that the entire film does not expand or contract during lamination.

The printing film laminated on the entire surface of the steel sheet has a portion not coated with an adhesive (4 mm in the above example).
There is an unnecessary portion of the width), and in order to remove this portion, it is necessary to make a cut at the boundary between the printed portion and the unnecessary portion. On this occasion,
It is necessary to consider that the surface of the steel sheet should be free of flaws, and it is important to adjust the depth of cut. In that sense, it is effective to burn off only the film with a heat quantity such that the underlying metal is not affected by the laser beam. Also, it is important that the adhesive has already hardened when making the score.

The notched laminate film layer is
Only the unnecessary portion (in the above-mentioned example, the 4 mm-width non-adhesive-coated portion) is continuously peeled and removed. If the cutting depth is adjusted well, the removal work can be continuously stripped and removed by gently pulling the unnecessary portion. Since this cutting depth adjustment is a highly advanced technique under high-speed operation, it is also effective to preliminarily perforate the printed film to assist the peeling work as an aid.

There is no residual substance on the surface of the steel sheet after the unnecessary portion is peeled off in this way, and it can be used as a welded portion after being cut out as a blank by slitting along the center line. .. The method for producing a strip laminated steel sheet according to the present invention is used in various forms in combination with conventional coating. For example, after applying a thermosetting coating on both the inner and outer surfaces of the can, a method of laminating a printed film only on the outer surface of the can, or applying a thermosetting coating on the inner surface of the can in stripes,
There are a method of directly laminating a printed film on the outer surface of the can, a method of laminating a film for the inner surface of the can on the inner surface of the can, and a method of laminating a printed film on the outer surface of the can.

[0020]

EXAMPLES Examples of the present invention will be described below. Example 1 A plate having a thickness of 0.17 mm and a tin plating having a deposition amount of 1.2 g / m ^{2 on} the surface and metal chromium 8 mg / m ² and hydrated chromium oxide 7 mg / m ² (as Cr) on the tin plating. On one surface of a thin steel plate having a width of 985 mm, a thermosetting epoxy resin was applied with a coating amount of 50 mg / m ^{2 to} a width of 159.8 mm, and the non-coated portion was applied to both ends thereof.
0 mm (163.8 mm in total) was provided, and continuous strip-shaped (striped) coating with 6 strips in the width direction was performed. Then, on the opposite surface, a thermosetting polyester resin containing a white pigment of titanium oxide is applied in a continuous strip shape with the same width at an adhesion amount of 120 mg / m ^{2 in} the positional relationship corresponding to the epoxy resin and then heated. The resin layers on the front and back were cured by heating for about 20 seconds.

The steel sheet heated to 270 ° C. as the highest temperature is rapidly cooled to 200 ° C. by a cooling roll,
It was used as a base for laminating a film for the outer surface of a can. Printing part 6 consisting of four layers of thermosetting adhesive / printing ink / saturated polyester resin / top coat layer and having a width of 159.8 mm
A multi-layer film with a total width of 984 mm (thickness 16 μm) each having a non-printed portion with a width of 2.0 mm at both ends thereof is unwound at the same speed as the steel plate traveling speed, and the printed portion (6 rows) with a width of 159.8 mm precedes it. Then, it was laminated on the surface of the steel sheet so as to overlap with the thermosetting polyester resin (6 rows) containing the titanium oxide-based white pigment applied. The steel sheet having a temperature of 200 ° C. at the time of lamination was cooled to room temperature by water cooling and the adhesive layer was fixed.

Thereafter, a sharp rotary blade is used to make a notch to reach the base at both ends of the non-printed portion existing on the film, and the leading end of the non-printed portion is pulled off with a pinch roll and peeled off near the roll. Suck into the installed vacuum suction port,
By continuously removing it to the outside of the system, a 4.0 mm-wide uncoated and unprinted portion was formed in a stripe shape. In these operations, peeling of 7 strips in the width direction was continuously performed simultaneously at a line speed of 200 mpm, so that printed portions of 6 strips in the width direction were exposed in stripes. The product wound into a coil can be cut at both ends with 2.0
It is cut into a blank size (163.8 x 136.2 mm) equivalent to a can diameter of 52.6 mm with a non-painted and non-laminated part of mm, and the multilayer film adhesive surface can be used as a can outer surface at the welding can line without any problem. It was

Example 2 A plate having a thickness of 0.18 mm and a plate width of 822 mm having a nickel plating of 0.58 g / m ^{2 on} the surface and a hydrated chromium oxide film of 7 mg / m ² (as Cr) on the nickel plating A thermosetting epoxy resin was applied to one side of the thin steel sheet of No. 2 in a stripe shape with a width of 200.6 mm (a non-painted portion having a width of 4.0 mm). This steel sheet was heated to a maximum attainable plate temperature of 280 ° C. in a heating time of about 16 seconds, baked, cooled to 180 ° C. by a cooling roll, and then sent to a pressure bonding roll.

A print part having a width of 200.6 mm and 4.0 mm consisting of four layers of low melting point adhesive layer / biaxially stretched polyester layer (containing 20 wt% of white pigment) / printing ink layer / top coat layer.
A film having a width of 820 mm having a non-printed portion having a width and having perforations for separating the two was laminated on the opposite sides of the epoxy resin coated surface which was previously coated in a positional relationship corresponding to the front and back sides.

After that, as in the case of Example 1, the both ends (above the perforations) of the non-printed portion existing on the film are cut with sharp rotary blades to the extent that the base is not reached, and the non-printed portion of the non-printed portion is cut. The leading edge is pulled off with a pinch roll, sucked into a vacuum suction port installed near the roll, and continuously removed outside the system to form a striped area with no painting or printing of 4.0 mm width. Formed. These tasks are
At a line speed of 200 mpm, peeling of 7 strips in the width direction was continuously performed at the same time, and the printed portions of 6 strips in the width direction were exposed in stripes.

This product was cut into a size of 204.6 × 125.0 mm and formed into a welded can having a can diameter of 65.0 mm and a can height (before lid winding) of 125.0 mm. Example 3 A thin steel plate having a plate thickness of 0.18 mm and a plate width of 985 mm, which has a nickel plating amount of 0.58 g / m ^{2 on} the surface and a hydrated chromium oxide film of 7 mg / m ² (as Cr) on the nickel plating. Was heated to 180 ° C. by high frequency heating and sent to a pressure bonding roll. On the other hand, a transparent biaxially stretched polyester film having a width of 983 mm (having a steel plate laminated portion having a width of 163.8 mm and a cut-and-removed portion having a width of 4 mm) having a low melting point adhesive layer in a stripe shape on one surface is provided on the steel plate surface. Laminated. The unnecessary portion having a width of 4 mm is cut at a predetermined position as in the first embodiment,
After peeling, it was sucked into a vacuum suction port installed near the cutting site and continuously discharged out of the system. After that, the steel sheet was heated again and sent to the second pressure-bonding roll at 200 ° C. In the second pressure-bonding roll, a printed film consisting of four layers of a low melting point adhesive layer / biaxially stretched polyester layer (containing 20 wt% of white pigment) / printing ink layer / top coat layer (with a printing portion having a width of 159.8 mm) A non-printed portion having a width of 4.0 mm) was laminated on the opposite surface of the transparent polyester film surface laminated in advance in a positional relationship corresponding to the front and back sides. After cooling
The non-printed portion having a width of 4 mm and having no adhesive was peeled off in the same manner as in Example 1.

The steel sheet having a striped laminated coating on the front and back thus produced has 165.8 × 136.2 mm having a non-laminated portion having a width of 2 mm at both ends as in Example 1.
Cut into blanks, the printing film laminated surface as the outer surface of the can, the diameter of the can is 52.6 mm, and the height of the can (before closing the lid) 13
It was molded into a 6.2 mm weld can.

[0028]

The invention guarantees many advantages. By ensuring highly accurate stripe laminating technology, continuous coating printing using coil products can be performed at high speed with a wide width, and productivity more than twice that of the cutting board coating line can be secured. You can next,
The work-in-process period can be shortened because it is not necessary to pass the line through many times. The use of coil products also has the advantage that even if the material plate is extremely thin, it does not cause such a great handling problem.
It is possible to solve all the problems in the conventional coating and printing process for a steel plate for a three-piece can, such as high quality printing appearance by gravure printing and labor saving by omitting steps.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B32B 31/08 7141-4F B65D 8/16 6540-3E // B29L 9:00 4F (72) Invention Oyagi Ochigi 20-1 Shintomi, Futtsu-shi, Chiba Central Research Division, Nippon Steel Co., Ltd. (72) Inventor Tomohiko Hayashi 20-1 Shintomi, Futtsu City, Chiba Central Research Division, Nippon Steel Co., Ltd.

Claims (5)

[Claims] 1. When laminating an organic resin film on a steel sheet surface in a striped pattern, after laminating a wide film on the entire surface of the steel sheet, continuous cuts are made in the laminated film layer, leaving only necessary portions on the steel sheet surface and leaving unnecessary portions. A method for producing a laminated steel sheet for a three-piece can, which comprises peeling and removing. 2. The method for producing a laminated steel sheet for a three-piece can according to claim 1, wherein the resin film laminated on the surface of the steel sheet has a printing ink layer for displaying a trademark design on the outer surface of the can. 3. The laminated steel sheet for a three-piece can according to claim 1, wherein the film laminated on the entire surface of the steel sheet has a perforation-like cut for separating the laminated portion and the non-laminated portion in advance. Method. 4. A method for producing a laminated steel sheet for a three-piece can, wherein the organic resin film is individually laminated on the front and back of the steel sheet by the method according to claim 1. 5. The method for producing a laminated steel sheet for a three-piece can according to claim 1, wherein a laser beam is used as a cutting means for cutting the film laminated on the surface of the steel sheet.