JP7213160B2 - Bottle can manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing bottle-cans filled with contents such as beverages.

2. Description of the Related Art As a can body to be filled and sealed with a content such as a beverage, a bottle can having a cap attached to an open end of the can is known. This bottle-can is generally formed in a bottomed cylindrical shape having a body and a bottom. A mouth portion is provided at the upper end of the portion. Such a bottle can has a body portion and a bottom portion by subjecting a metal plate material (aluminum alloy plate material) to a cupping process (drawing process), a DI process (drawing and ironing process, Drawing & Ironing), and a trimming process. It is formed into a bottomed cylindrical cylinder, and a shoulder part and a diameter-reduced part are formed by performing a diameter reduction process (necking process) on the trunk part of the bottomed cylinder. Then, a mouth portion forming step is performed to form a bulging portion, a screw portion, and the like on the mouth portion whose diameter has been reduced by the necking step. In such a bottle can, printing and overcoating are performed on the bottomed cylinder after the drawing, ironing and trimming steps.

If the outer surface of such a cylindrical body is printed and a transparent coating (overcoat) is applied to the entire outer peripheral surface including the printed layer with the same thickness, the diameter reduction rate in the necking process is large. may crack or the coating may peel off. For this reason, as in Patent Documents 1 and 2, in a cylindrical cylinder having a bottom, the coating amount of the coating film on the area that becomes the neck part and the thread part by subsequent processing (coating amount per unit area and coating thickness, etc.) is known.

For example, in the method of Patent Document 1, it is disclosed to form a coating film thinner than other can body portions on a threaded portion of a cylindrical body and on a region to be a curled portion formed at the upper end of the threaded portion.
In addition, for example, in the method of Patent Document 2, the coating formed on the outer peripheral surface of the can body that is diameter-reduced is greater than the coating film that is formed on the outer peripheral surface of the can body that is not diameter-reduced. Reducing the coating weight per unit area of film is disclosed.
On the other hand, Patent Document 3 describes a so-called two-piece can in which the outer peripheral surface of the cylindrical body is not reduced in diameter, but the coating film on the upper and lower ends of the can where the cans contact each other is applied to the coating film on the central part of the can. It is disclosed that the outer appearance of the product is maintained by increasing the thickness of the can to suppress scratches or the like during the handling of the can during the can manufacturing process, beverage filling process, distribution process, and the like.

JP-A-2006-232347 JP-A-9-29367 JP-A-3-56176

By the way, in recent years, there has been a demand for expanding the content of bottle-cans. In this case, in order to increase the internal capacity of the bottle can, it is conceivable to increase the diameter of the bottle can. In this case, it is possible to increase the capacity by increasing the height of the cylindrical body of the bottle can or decreasing the angle of inclination of the diameter-reduced portion with respect to the can axis. In particular, if an attempt is made to increase the capacity by reducing the angle of inclination of the diameter-reduced portion with respect to the can axis, the expansion of the diameter-reduced portion in the direction of the can axis increases, making molding difficult. Therefore, if the methods disclosed in Patent Documents 1 to 3 are applied as they are, the coating film may float during the bottle-can necking process or the subsequent irrigation process, and the printed layer may peel off. In addition, if the coating film floats during screw forming of the bottle can, the threaded portion may become rough and the opening torque may increase.

It is an object of the present invention to provide a method for manufacturing bottle cans that can suppress the occurrence of paint film floating, suppress print peeling, and suppress an increase in torque during opening. aim.

A method for manufacturing a bottle can according to the present invention comprises a printing step of printing the outer surface of a cylindrical cylinder having a bottom, and forming a transparent coating film on the outer peripheral surface including the printed layer of the cylinder after the printing step. an overcoating step, and a cylindrical body portion formed by processing the cylindrical body after the overcoating step, and a shoulder formed continuously from the cylindrical body portion and positioned above the cylindrical body portion in the can axial direction. a reduced-diameter portion whose diameter decreases from the upper end of the shoulder portion toward the upper side in the can axial direction with respect to the cylindrical body portion; and a mouth portion forming step of processing the small diameter portion to form a mouth portion having a threaded portion. A is the film thickness of the coating film of A, B is the film thickness of the coating film in the region that will be the diameter-reduced portion of the cylindrical body, and D is the film thickness of the coating film in the region that will be the body portion of the cylindrical body , A<B<D.

In the present invention, the thickness B of the coating film in the region of the cylindrical body that will be the reduced diameter portion is formed to be thinner than the thickness D of the coating film in the region that will be the body portion of the cylindrical body. It is possible to suppress peeling of the printed layer due to floating of the coating film when the area to be the part extends in the can axial direction by the necking process. In addition, since the threading in the mouth part forming process is more severe than the necking process, the thickness A of the coating film in the area that will be the mouth part of the cylinder is the neck part of the cylinder. It is formed thinner than the film thickness B of the region. As a result, it is possible to suppress floating of the coating film during screw forming of the bottle can, and to suppress an increase in opening torque due to roughness of the threaded portion.

In a preferred embodiment of the method for manufacturing a bottle can of the present invention, in the overcoating step, C is the film thickness of the coating film in the region that will be the shoulder portion of the cylindrical body, and the region that will be the body portion of the cylindrical body is Of the film thickness D of the coating film in , where D2 is the thickness of the coating film in the bottom side region and D1 is the thickness of the coating film in the region excluding the bottom side region, D1 ≤ C, and , D1<D2.

Here, the shoulder portion of the bottle-can and the bottom side region of the trunk portion of the cylindrical body are the portions where the bottle-cans come into contact with each other during the filling line for filling the contents into the bottle-cans and during transportation.
In the above aspect, in the region to be the body portion, the film thickness D2 of the coating film in the bottom side region is formed thicker than the film thickness D1 of the coating film in the region excluding the bottom side region, and the region to be the shoulder portion is formed. Since the film thickness C of the coating film is formed to a thickness equal to or greater than the coating film D1 in the region excluding the bottom side region, even if the bottle cans come into contact with each other in the filling line or during transportation, the coating film will be scratched and the bottle will be damaged. It is possible to suppress spoiling the appearance of the can.

In a preferred embodiment of the method for manufacturing a bottle can of the present invention, in the overcoating step, the paint that will form the coating film is applied to the outer surface of the cylindrical body by rotating the cylindrical body one or more times but less than two times, A single region where the paint is applied only once is formed by the first round of the cylindrical body, and the thickness B1 of the coating film in the single region out of the thickness B of the coating film in the region to be the diameter-reduced portion is formed. should be 45 mg/dm ² or more.

If the film thickness B1 of the coating film in the single region is less than 45 mg/dm ² , the strength of the coating film is insufficient, and the print layer may peel off during the necking process.

In a preferred embodiment of the bottle-can manufacturing method of the present invention, the film thickness B1 of the coating film is preferably 80 mg/dm ² or less.

If the film thickness B1 of the coating film in the region to be the diameter-reduced portion exceeds 80 mg/dm ² , the coating film is too thick, and the coating film may float during the necking process, resulting in roughness.

In a preferred embodiment of the bottle-can manufacturing method of the present invention, in the overcoating step, the paint that will form the coating film is applied to the outer surface of the cylindrical body while rotating the cylindrical body two or more times.

In the above-described aspect, since the paint to be the coating film is applied in at least two layers, peeling of the printed layer and floating of the coating film can be reliably suppressed.

In a preferred embodiment of the method for manufacturing a bottle can according to the present invention, in the overcoating step, a double region is formed in which the paint is applied in a double manner on the second round of the cylindrical body, and the region becomes the diameter-reduced portion. Of the film thickness B of the coating film in , the film thickness B2 of the coating film in the double region is preferably 60 mg/dm ² or more and 112 mg/dm ² or less.

In the above aspect, the film thickness B2 of the coating film in the double area where the coating material that forms the coating film is applied in two layers is set within the above range. In particular, since the diameter-reduced portion has a large elongation in the can axial direction, if the thickness of the coating film in the region to be the diameter-reduced portion is less than 60 mg/dm ² , the printed layer may peel off during the necking process. If it exceeds 112 mg/dm ² , the coating film may float during the necking process, resulting in roughness.

In a preferred embodiment of the method for manufacturing a bottle can of the present invention, in the overcoating step, the paint that will form the coating film is applied to the outer surface of the cylindrical body while rotating the cylindrical body two or more times and less than three times. , a double region where the paint is applied twice in the second round of the cylindrical body, and a triple region in which the paint is applied three times by the third round of the cylindrical body.

In the above aspect, since the paint that forms the coating film is applied in at least two layers, peeling of the printed layer and paint film floating can be reliably suppressed, and the number of paints that form the coating film does not exceed three layers, so the necking process can be performed. It is possible to suppress the paint film floating at times and reduce the possibility of roughening.

According to the present invention, in cans, such as bottle cans, in which the body is largely processed after the printing and overcoating processes, it is possible to suppress the peeling of the paint film by suppressing the peeling of the paint film, as well as suppressing the increase in torque when opening. can be suppressed.

1 is a front view showing a bottle-can manufactured by a bottle-can manufacturing method according to an embodiment of the present invention; FIG. FIG. 4 is a schematic diagram showing each region where a coating film is formed on the outer peripheral surface of the cylindrical body in the overcoating step of the manufacturing process of the bottle can of the embodiment. FIG. 4 is a diagram showing the manufacturing process of the bottle can of the above embodiment in the order of (a) to (c), (a) and (b) being longitudinal cross-sectional views passing through the can axis, and (c) being a front view. It is a fragmentary sectional view showing the state where the printing layer and the paint film were formed in the peripheral face of the cylinder of the above-mentioned embodiment. It is a schematic diagram which shows schematic structure of the coating apparatus for forming a coating film on the outer peripheral surface of the cylinder of the said embodiment. FIG. 5 is a schematic diagram for comparing groove depths of gravure rolls of the coating apparatus of the above embodiment. It is a front view which shows the bottle can which concerns on the modification of the said embodiment. FIG. 10 is a schematic diagram showing each region where a coating film is formed on the outer peripheral surface of the cylindrical body in the overcoating step of the manufacturing process of the bottle can of the modification.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a front view of a bottle can according to one embodiment of the present invention. The bottle can 1 is used as a container for containing beverages and the like by attaching a cap (not shown) to the open end 1a.
The bottle can 1 manufactured by the manufacturing method of the present embodiment is made of a thin sheet metal such as aluminum or an aluminum alloy (for example, an Al—Mn-based aluminum alloy), and as shown in FIG. 12, a shoulder portion 130 positioned at the upper end of the cylindrical body portion 12, a reduced diameter portion 13 that decreases in diameter from the upper end of the shoulder portion 130 toward the upper side in the can axial direction, and a diameter formed at the upper end of the reduced diameter portion 13. and a mouth 14 of 38 mm. Moreover, the height H1 of the bottle can 1 is set to 194 mm or more and 230 mm or less (for example, 210 mm).

The barrel portion 12 is formed in a cylindrical shape that extends linearly in the direction along the can axis S, and has an outer diameter w1 of 64 mm or more and 68 mm or less, for example 66.2 mm. A dome-shaped bottom portion 11 is formed at the lower end portion of the cylindrical body portion 12. The bottom portion 11 is positioned on the can axis S and bulges upward (inside the cylindrical body portion 11). and a heel portion 112 connecting the outer peripheral edge portion of the dome portion 111 and the lower end portion of the barrel portion 12 . In addition, the connecting portion between the dome portion 111 and the heel portion 112 is bent downward in the can axial direction so that the bottle-can 1 is in an upright position (the mouth portion shown in FIG. 1). 14 faces upward), the contact portion 113 is in contact with the mounting surface. The ground contact portion 113 protrudes downward most from the bottom portion 11 and has an annular shape extending in the circumferential direction. The diameter w2 of this grounding portion 113 is set to, for example, 56 mm.

The shoulder portion 130 is positioned at the upper end of the barrel portion 12 on the upper side in the can axial direction. The shoulder portion 130 is a portion that comes into contact with other bottle-cans 1 during transport of the bottle-can 1, and connects the cylindrical body portion 12 and the reduced-diameter portion 13 to each other. Moreover, the height H2 from the ground contact portion 113 of the bottom portion 11 to the shoulder portion 130 is set to 110 mm or more and 150 mm or less (for example, 125 mm).

The reduced diameter portion 13 has a convex curved portion 131 on the lower side in the can axial direction and a concave curved portion 132 on the upper side, which are smoothly connected. In this case, the radius of curvature R2 of the concave curved portion 132 on the upper side is set larger than the radius of curvature R1 of the convex curved portion 131 on the lower side. Specifically, the convex curved portion 131 has an outer surface curvature radius R1 of 50 mm or more and 70 mm, and the concave curved portion 132 has an outer surface curvature radius R2 of 90 mm or more and 110 mm or less.

At the upper end of the concave curved portion 132 in the can axis direction, a lower convex portion 133 that protrudes radially outward in a longitudinal section including the can axis S and a lower convex portion 133 that protrudes in the can axis direction An upper recessed portion 134 is formed continuously on the upper side and is recessed radially inward in a longitudinal section. The lower convex portion 133 is connected to the upper end of the concave curved portion 132 in the can axial direction, and the upper concave portion 134 is formed between the reduced diameter portion 13 and the mouth portion 14 and has a cylindrical shape with a smaller diameter than the mouth portion 14 . It is connected to neck 15 . Therefore, the upper end portion of the concave curved portion 132 has a constricted shape.

The mouth portion 14 has a bulging portion 141 formed in the circumferential direction on the neck portion 15 described above, a threaded portion 142 formed on the bulging portion 141, and a curled portion at the open end 1a above the threaded portion 142. 143 are formed. Then, a cap (not shown) is screwed onto the threaded portion 142, and the liner on the inner surface of the cap is pressed against the curled portion 143 in a state where the hem of the cap is caught in the bulging portion 141 to seal the inside.

In order to manufacture this bottle can 1, first, an aluminum plate material is punched and drawn to form a relatively large-diameter shallow cup 21 as shown in FIG. 3(a) (cup forming step). Thereafter, drawing and ironing (DI processing) are applied to the cup 21 again to form a bottomed cylinder 22 having a predetermined height as shown in FIG. process)). Since this drawing and ironing process produces ears at the upper end of the cylindrical body 22, the upper end is trimmed to make the heights uniform in the circumferential direction (trimming step). By this drawing and ironing process, the bottom portion of the cylindrical body 22 is molded into the shape of the bottom portion 11 of the final bottle can 1 .

Next, after degreasing and chemical conversion treatment of the cylindrical body 22, it is supplied to a printing device (not shown), and printed on the outer peripheral surface 22a to form a printed layer 221 (printing step), and supplied to the coating device 40. A transparent coating film 222 (overcoat or finish varnish) is formed on the entire outer peripheral surface 22a including the printed layer 221 (overcoating step), and the coated cylindrical body 22 is passed through an oven to form the printed layer 221 and the coating. The membrane 222 is baked and dried (exterior print coating step). As a result, a printed layer 221 and a coating film 222 are formed on the outer peripheral surface of the cylinder 22, as shown in FIG. Although FIG. 2 shows the cylindrical body 22 after printing and painting, only the coating film 222 is shown with reference numerals for convenience. This coating film 222 is formed with a wider area than the print layer 221 .

Also, as the paint P (see FIG. 5) that is the raw material of the coating film 222, various paints can be used, ranging from those having a surface tension smaller than that of the ink to those having a surface tension higher than that of the ink. For example, it is made of resin such as polyester, epoxy, acryl, and amide. Specifically, it is formed by dissolving a cured epoxy-phenol-based resin or a cured polyester-amino-based resin in a solvent and adding wax thereto. The wax added to the raw material includes carnauba wax, microcrystalline, and the like.

In addition, the paint P can be a mixture of additives such as scaly particles, foaming particles, and light diffusely reflecting particles. , it is preferable to mix additives. For example, by coating smooth flake surfaces with metal oxides or silica, pearl pigments that exhibit iridescent colors and color prop properties (the property of changing light brightness and hue depending on the viewing angle), foaming paints with added foaming agents, silica matte paint mixed with, base coat paint mixed with titanium pigment, and paint containing additives such as aluminum paste paint mixed with aluminum powder can be preferably used.

(Configuration of coating equipment)
A coating apparatus 40 as shown in FIG. 5 is used for the overcoating step of the can manufacturing method of the present embodiment. The coating apparatus 40 includes a paint supply unit 41, a gravure roll 42, and an applicator roll 43. The paint P supplied from the paint supply unit 41 is applied to the outer peripheral surface 43a of the applicator roll 43 using the gravure roll 42. The outer peripheral surface 22 a of each cylindrical body 22 is attached to the outer peripheral surface of the applicator roll 43 while sequentially transporting the plurality of cylindrical bodies 22 along the transport path 45 such that each axis revolves in a substantially circular shape. The paint P is applied by bringing the 43a into contact.

The outer peripheral surface 43a of the applicator roll 43 is made of rubber or the like, and acrylonitrile-butadiene rubber (NBR), for example, can be suitably used as the material of the outer peripheral surface 43a. Also, the applicator roll 43 is provided rotatably about its rotation axis S3, and below the conveying passage 45 so that the upper part of the outer peripheral surface 43a overlaps the coating position of the conveying passage 45. are placed. The rotation direction X3 of the applicator roll 43 is opposite to the revolution direction X1 of the cylinder 22 conveyed through the conveying path 45 .

The gravure roll 42 is made of a hard material such as stainless steel or steel and has a cylindrical shape. It has become. Also, the gravure roll 42 is rotatable around its rotation axis S2, and is arranged upstream of the coating position of the applicator roll 43 in the rotation direction X3. By bringing the outer peripheral surface 42 a of the gravure roll 42 into sliding contact with the outer peripheral surface 43 a of the applicator roll 43 , the paint P is adhered to the outer peripheral surface 43 a of the applicator roll 43 . The rotation axis S2 of the gravure roll 42 and the rotation axis S3 of the applicator roll 43 are arranged in parallel, and the rotation direction X2 of the gravure roll 42 is opposite to the rotation direction X3 of the applicator roll 43. , are synchronously rotated in opposite directions.

Next, a method of coating the cylindrical body 22 by the can coating apparatus 40 will be described.
First, the paint P is supplied from the paint supply unit 41 onto the outer peripheral surface 42a of the gravure roll 42, and the paint P is evenly adhered to the entire outer peripheral surface 42a. The paint P adhering to the outer peripheral surface 42a of the gravure roll 42 moves with its rotation, adheres to the outer peripheral surface 43a of the applicator roll 43 rotating in the opposite direction to the gravure roll 42, and adheres to the applicator roll 43. As the applicator roll 43 rotates, the paint P sequentially moves in the rotation direction X3.

Then, the outer peripheral surface 22a of the cylindrical body 22 conveyed to the coating position is brought into contact with the outer peripheral surface 43a of the applicator roll 43 to which the paint P is adhered at the coating position, and the applicator roll 43 and the cylindrical body 22 are rolled in opposite directions to each other, and the cylindrical body 22 is rotated one or more rounds on the outer peripheral surface 43 a of the applicator roll 43 . In the coating device 40, the cylindrical body 22 is configured to rotate in a direction opposite to the rotation direction X3 of the applicator roll 43 (direction of arrow Y) at the coating position in synchronism with the rotation of the applicator roll 43. Along with the rotation of the applicator roll 43 and the rotation of the cylindrical body 22, the paint P on the outer peripheral surface 43a of the applicator roll 43 is applied (transferred) to the outer peripheral surface 22a in sequence, and a coating film 222 is formed on the outer peripheral surface 22a. be.

At this time, the viscosity of the paint P supplied to the applicator roll 43, the coating amount of the paint P deposited on the outer peripheral surface 43a, and the rotation speed (rotational speed) of the cylindrical body 22 rolling on the outer peripheral surface 43a of the applicator roll 43 are , the number of coatings of the cylindrical body 22 with respect to the required coating amount of the coating film 222 formed on the outer peripheral surface 22a, that is, the number of revolutions of the cylindrical body 22 rotating on the outer peripheral surface 43a of the applicator roll 43.
For example, in the overcoating process of the present embodiment, the cylindrical body 22 is rotated one or more turns and less than two turns. For this reason, when applying the paint P to be the coating film on the outer peripheral surface 22a of the cylinder 22, the single area where the paint P is applied only once during the first round of the cylinder 22 and the second circle of the cylinder 22 cause A double region where the paint P is applied in two is formed.

Next, paint is sprayed onto the inner peripheral surface of the cylindrical body 22 by a spray or the like to coat the inner surface, which is then baked and dried (inner surface coating step).
After that, the upper end portion of the cylindrical body 22 is formed, and as shown in FIG. The diameter-reduced portion 13 is formed, and the small-diameter cylindrical portion 231 is formed thereabove to form the first intermediate formed body 23 (necking step). Then, as shown in FIG. 3( d ), the neck portion 15 is formed in the small-diameter cylindrical portion 231 of the first intermediate molded body 23 to form the small-diameter portion 241 to form the second intermediate molded body 24 . Then, the small-diameter portion 241 is processed to form the mouth portion 14 having a bulging portion 141 protruding radially outward, a threaded portion 142, and a curled portion 143 (mouth portion forming step).

In the outer surface coating step in this series of manufacturing steps, the coating film 222 is baked on the entire area of the outer peripheral surface 22a of the cylindrical body 22 and dried.
Here, since the aluminum alloy plate, which is the material of the bottle can 1, has different elongations in the rolling direction and the crossing direction, the film thickness of the coating film 222 formed on the entire region of the outer peripheral surface 22a of the cylindrical body 22 is the same. As for the film thickness, it is not possible to reduce the peeling of the printed layer and the roughness caused by the floating of the coating film during the necking process of the bottle can 1 . In addition, if the coating film floats during screw forming of the bottle can 1, the threaded portion 142 may become rough and the opening torque may increase.

Therefore, in the present embodiment, the coating amount of the paint P in the overcoating process is adjusted.
FIG. 2 shows the outer peripheral surface 22a of the cylindrical body 22 after the outer surface printing and coating process (after the overcoating process). All areas are coated. The coating film 222 includes a region that becomes the mouth portion of the cylindrical body 22 (hereinafter referred to as first coating region Ar1), a region that becomes the reduced diameter portion 13 of the cylindrical body 22 (hereinafter referred to as second coating region Ar2), It is formed in a region that will be the shoulder portion 130 (hereinafter referred to as a third application region Ar3) and a region that will be the body portion of the cylinder. Among these, the region that becomes the body portion is a bottom side region (hereinafter referred to as a fifth coating region Ar5) located on the bottom 11 side and a region (hereinafter referred to as a fourth coating region Ar5) excluding the bottom side region (fifth coating region Ar5) (referred to as application area Ar4).

In the overcoating step, the thicknesses of the coating films 222a to 222e applied to the first to fifth coating regions Ar1 to Ar5 on the outer peripheral surface 22a of the cylindrical body 22 are as follows. Specifically, the film thickness of the coating film 222a in the first coating region Ar1 is A, the film thickness of the coating film 222b in the second coating region Ar2 is B, and the region to be the body (fourth and fifth coating regions Ar4, When the film thickness of the coating film 222d of Ar5) is D, A<B<D. That is, in the overcoating process, the film thickness A of the coating film 222a applied to the first coating region Ar1 and the coating applied to the second coating region Ar2 are higher than the film thickness D of the coating film 222d in the region that becomes the body. The film thickness B of the film 222b is formed thin, and the film thickness A of the coating film 222a applied to the first application region Ar1 is set thinner than the film thickness B of the coating film 222b applied to the second application region Ar2. It is

Furthermore, the film thickness of the coating film 222c in the third coating region Ar3 is C, the film thickness D of the coating film 222d in the body region is D2, and the thickness of the coating film 222d2 in the fifth coating region Ar5 is D2. When the film thickness of the coating film 222d1 in the coating region Ar4 is D1, D1≦C and D1<D2. That is, in the overcoating step, the film thickness D2 of the coating film 222d2 applied to the fifth coating region Ar5 is set thicker than the film thickness D1 of the coating film 222d1 of the fourth coating region Ar4, and The film thickness C of the coating film 222c applied to Ar3 is set to be greater than or equal to the thickness D1 of the coating film 222d applied to the fourth application region Ar4.
The printed layer 221 is formed in the second to fifth coating regions Ar2 to Ar5. That is, only the coating film 222a is applied to the first application region Ar1.

In this embodiment, the film thickness A of the coating film 222a in the first coating region Ar1 is 30 mg/ ^dm2 or more and 65 mg/ ^dm2 or less, and the film thickness B (B1) of the coating film 222b in the second coating region Ar2 is 45 mg. / ^dm2 or more and 80 mg/ ^dm2 or less, the film thickness C of the coating film 222c in the third coating region Ar3 is 55 mg/ ^dm2 or more and 100 mg/ ^dm2 or less, the film thickness D1 of the coating film 222d1 in the fourth coating region Ar4 is , 50 mg/dm ² or more and 90 mg/dm ² or less, and the film thickness D2 of the coating film 222d2 in the fifth coating region Ar5 is 55 mg/dm ² or more and 100 mg/dm ² or less.
The numerical range of the film thicknesses A to D2 indicates the numerical range in the single area where the coating film 222 is applied only once during the first round of the cylindrical body 22 . Further, the numerical range in the double area where the paint is applied in double by the second round of the cylindrical body 22 is, for example, 1.3 to 1.4 times the various numerical ranges, and the coating film 222b of the second coating area Ar2. The film thickness B2 of is 60 mg/dm ² or more and 112 mg/dm ² or less.

If the film thickness B1 of the coating film 222b in the second coating region Ar2 in the single region is less than 45 mg/dm ² , the strength of the coating film is insufficient, and the printing layer may peel off during the necking process. When the film thickness B1 exceeds 80 mg/dm ² , the coating film is too thick, and the coating film may float during the necking process, resulting in roughness. In addition, since the second coating region Ar2 that becomes the diameter-reduced portion 13 has a large elongation in the can axis direction, the film thickness B2 of the coating film 222b in the second coating region Ar2 in the double coating region is less than 60 mg/ ^dm2 . , the print layer 221 may peel off during the necking process, and if it exceeds 112 mg/dm ² , the coating film may float during the necking process, resulting in roughness.
Further, the film thickness B1 of the coating film 222b in the second coating region Ar2 of the single region is more preferably 45 mg/dm ² or more and 60 mg/dm ² or less. More preferably, the film thickness B2 is 60 mg/dm ² or more and 85 mg/dm ² or less. In this case, it is possible to reliably prevent peeling and roughening of the printed layer during the necking process.

Further, the height H10 of the cylindrical body 22 is slightly larger than the height H0 of the bottle can 1, and is 198 mm to 210 mm (eg, 202 mm). Further, the height H3 of the bottom portion 11 of the cylindrical body 22 where the coating film 222 is not applied is 5 mm to 11 mm (eg, 7 mm), and the height H4 of the fifth coating area Ar5 in the cylindrical body 22 is 10 mm to 20 mm (eg, 15 mm). ), the height H5 of the fourth application area Ar4 in the cylinder 22 is 80 mm to 100 mm (eg, 93 mm), and the height H6 of the third application area Ar3 in the cylinder 22 is 15 mm to 25 mm (eg, 20 mm). . In this regard, the third application region Ar3 is a region that becomes the shoulder portion 130 of the cylindrical body 22, but is set to be larger than the actual height of the shoulder portion, and there is a possibility that the necking process may slightly shift the position thereof. Therefore, as described above, a certain width is provided so that the height H2 from the ground contact portion 113 of the bottom portion 11 of the bottle can 1 to the shoulder portion 130 is positioned at the center of the third application area Ar3 in the height direction. is set to
Further, the height H7 of the second application area Ar2 on the cylinder 22 is 20 mm to 60 mm (eg, 42 mm), and the height H8 of the first application area Ar1 on the cylinder 22 is 15 mm to 35 mm (eg, 23 mm). It is

The above-described coating device 40 is employed for coating the coating material P on the cylindrical body 22, and the gravure roll that supplies the coating material P to the outer peripheral surface 43a of the applicator roll 43 that contacts each of the coating regions Ar1 to Ar5. 42 are set so that the film thicknesses A to D2 of the coating films 222a to 222d2 made of the coating material P applied to the respective coating regions Ar1 to Ar5 are within the above numerical ranges. Specifically, the depth and number of grooves (image lines) formed on the outer peripheral surface 42a of the gravure roll 42 are different for each coating region corresponding to each of the coating regions Ar1 to Ar5. The greater the depth and the number of the drawing lines, the more the paint P is included. It is applied to the outer peripheral surface 22 a of the cylindrical body 22 .

More specifically, as shown in FIG. 6, the depth and number of the image lines 421a formed in the first area Ar10 corresponding to the first coating area Ar1 on the outer peripheral surface 42a of the gravure roll 42 are the same as those in the second coating area Ar2. is set to be smaller than the depth of the image lines 421b formed in the second region Ar20 corresponding to , and the number of lines is also set to be smaller. Further, the depth and the number of the image lines 421b formed in the second area Ar20 are set smaller than the depth and the number of the image lines 421d1 formed in the fourth area Ar40 corresponding to the fourth application area Ar4. It is Furthermore, the depth and number of the drawing lines 421c and 421d2 of the third area Ar30 corresponding to the third coating area Ar3 and the fifth area Ar50 corresponding to the fifth coating area Ar5 are the same, and the fourth area The depth is set larger than the depth of the image line 421d1 formed in Ar40.

The outer peripheral surface 43a of the applicator roll 43 corresponding to the first to fifth regions Ar10 to Ar50 of the gravure roll 42 is supplied with the paint P corresponding to each of the regions Ar10 to Ar50, and the outer peripheral surface 43a of the applicator roll 43 By rotating the cylindrical body 22 one or more times and less than two times, the film thicknesses A to D2 of the coating films 222a to 222d2 in the respective coating regions Ar1 to Ar5 can be set within the above numerical range.

In the present embodiment, the thickness B of the coating film in the area of the cylindrical body that will be the reduced diameter portion is formed to be thinner than the thickness D of the coating film in the area that will be the body portion of the cylindrical body. It is possible to suppress peeling of the printed layer due to floating of the coating film when the region that becomes the diameter portion extends in the can axial direction by the necking process. In addition, since the threading in the mouth part forming process is more severe than the necking process, the thickness A of the coating film in the area that will be the mouth part of the cylinder is the neck part of the cylinder. It is formed thinner than the film thickness B of the region. As a result, it is possible to suppress floating of the coating film during screw forming of the bottle can, and to suppress an increase in opening torque due to roughness of the threaded portion.

In addition, in the body portion region, the coating film thickness D2 of the bottom side region and the coating film thickness C of the shoulder region are thicker than the coating film thickness D1 of the region excluding the bottom side region. Since it is formed, even if the bottle-cans come into contact with each other in the filling line or during transportation, it is possible to prevent the coating film from being scratched and spoiling the appearance of the bottle-cans.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.
For example, in the above-described embodiment, the diameter-reduced portion 13 of the bottle can 1 has a shape having a convex curved portion 131 and a concave curved portion 132. However, the present invention is not limited to this. It may have a planarly inclined shape.

FIG. 7 is a front view showing a bottle-shaped can 1A according to a modified example of the above embodiment, and FIG. 8 shows the coating of the outer peripheral surface 52a of the cylinder 52 in the overcoating step of the manufacturing process of the bottle-shaped can 1A according to the above-described modified example. It is a schematic diagram which shows each area|region in which a film|membrane is formed. In addition, in the following description, the same or substantially the same configuration as that of the above embodiment is given the same number, and the description is omitted or simplified.
As shown in FIG. 7, a bottle can 1A of this modified example has a barrel portion 12A having a bottom portion 11, a shoulder portion 130 positioned at the upper end of the barrel portion 12A, and an upper end of the shoulder portion 130 in the can axial direction. It has a diameter-reduced portion 13A whose diameter decreases as it extends toward the center, and a mouth portion 14 formed at the upper end of the diameter-reduced portion 13A. That is, the bottle can 1A of this modified example is partially different from the above-described embodiment in the shape of the barrel portion 12A and the reduced diameter portion 13A. Further, the height H9 of the bottle can 1 is set to 195 mm or more and 210 mm or less (for example, 198.6 mm).

The shoulder portion 130 is positioned at the upper end of the barrel portion 12A on the upper side in the can axial direction. The shoulder portion 130 is a portion that comes into contact with another bottle-can 1A during transportation of the bottle-can 1A, and connects the barrel portion 12A and the diameter-reduced portion 13A. A height H30 from the ground contact portion 113 of the bottom portion 11 to the shoulder portion 130 is set to 140 mm or more and 155 mm or less (for example, 147 mm). That is, in this modified example, the length of the barrel portion 12A is longer than in the above embodiment.
The diameter-reduced portion 13A has a shape extending in a straight line from the upper end of the shoulder portion 130 in the can-axis direction in a vertical cross-sectional view, and the length in the can-axis direction is the same as in the above embodiment. It is formed smaller than the length of diameter portion 13 . Also, the curvature radius R3 of the lower end portion of the reduced diameter portion 13A is formed to be 5 mm or more and 12 mm or less. The upper end of the linearly extending reduced diameter portion 13A is connected to a lower convex portion 133, and an upper concave portion 134 is formed between the reduced diameter portion 13A and the mouth portion 14 and has a cylindrical shape with a smaller diameter than the mouth portion 14. It is connected to neck 15 .

Like the bottle can 1 of the above-described embodiment, such a bottle can 1A is formed by forming a cup by a cup forming process, and applying drawing and ironing (DI processing) again to form a cylindrical body 52 with a bottom. (Drawing and ironing process (DI process)). Then, after the cylindrical body 52 is degreased and chemically treated through a trimming process, it is supplied to a printing device (not shown), and the outer peripheral surface 52a is printed to form a printed layer (printing process), and a coating device is used. 40 to form a transparent coating 522 (overcoat or finish varnish) on the entire outer peripheral surface 52a including the printed layer (overcoat step), and pass the coated cylindrical body 52 through an oven to pass the printed layer. And the coating film 522 is baked and dried (outer surface printing coating step).

In the overcoating step, the thicknesses of the coating films 522a to 522e applied to the first to fifth coating regions Ar1 to Ar5 on the outer peripheral surface 52a of the cylinder 52 are as follows. Specifically, the film thickness of the coating film 522a in the first coating region Ar1 is A, the film thickness of the coating film 522b in the second coating region Ar2 is B, and the region to be the body (fourth and fifth coating regions Ar4, When the film thickness of the coating film 522d of Ar5) is D, A<B<D. Furthermore, the film thickness of the coating film 522c in the third coating region Ar3 is C, the film thickness D of the coating film 522d in the body region is D2, and the film thickness of the coating film 522d2 in the fifth coating region Ar5 is D2. When the film thickness of the coating film 522d1 in the coating region Ar4 is D1, D1≦C and D1<D2.

In this modification, the film thickness A of the coating film 522a in the first coating region Ar1 is 30 mg/ ^dm2 or more and 65 mg/ ^dm2 or less, and the film thickness B (B1) of the coating film 522b in the second coating region Ar2 is 45 mg. / ^dm2 or more and 80 mg/ ^dm2 or less, the film thickness C of the coating film 522c in the third coating region Ar3 is 55 mg/ ^dm2 or more and 100 mg/ ^dm2 or less, the film thickness D1 of the coating film 522d1 in the fourth coating region Ar4 is , 50 mg/dm ² or less and 90 mg/dm ² or less, and the film thickness D2 of the coating film 522d2 in the fifth coating region Ar5 is 55 mg/dm ² or more and 100 mg/dm ² or less.
The numerical range of the film thicknesses A to D2 indicates the numerical range in the single area where the paint is applied only once during the first round of the cylindrical body 52 . Further, the numerical range in the double area where the paint is applied in double by the second round of the cylindrical body 52 is, for example, 1.3 to 1.4 times the various numerical ranges, and the coating film 522b of the second coating area Ar2. The film thickness B2 of is 60 mg/dm ² or more and 112 mg/dm ² or less.
Further, the film thickness B1 of the coating film 222b in the second coating region Ar2 of the single region is more preferably 45 mg/dm ² or more and 60 mg/dm ² or less. More preferably, the film thickness B2 is 60 mg/dm ² or more and 85 mg/dm ² or less. In this case, it is possible to reliably prevent peeling and roughening of the printed layer during the necking process.

Further, the height H90 of the cylindrical body 52 is slightly larger than the height H9 of the bottle can 1A, and is 198 mm to 210 mm (eg, 199 mm). Further, the height H31 of the bottom portion 11 of the cylindrical body 52 where the coating film 522 is not applied is 5 mm to 11 mm (eg, 7 mm), and the height H32 of the fifth coating area Ar5 in the cylindrical body 52 is 10 mm to 20 mm (eg, 15 mm). ), the height H33 of the fourth coating region Ar4 in the cylinder 52 is 100 mm to 120 mm (eg, 115 mm), and the height H34 of the third coating region Ar3 in the cylinder 52 is 10 mm to 20 mm (eg, 15 mm). . In this regard, the third application region Ar3 is a region that becomes the shoulder portion 130 of the cylindrical body 52, but is set to be larger than the actual height of the shoulder portion, and there is a possibility that the necking process may slightly shift the position thereof. Therefore, as described above, a certain width is provided so that the height H30 from the ground contact portion 113 of the bottom portion 11 of the bottle can 1A to the shoulder portion 130 is positioned at the center of the third application area Ar3 in the height direction. is set to
Further, the height H35 of the second application area Ar2 in the cylinder 52 is 10 mm to 30 mm (eg, 20 mm), and the height H36 of the first application area Ar1 in the cylinder 52 is 15 mm to 35 mm (eg, 23 mm). It is

The bottle can 1A of this modified example differs from the bottle can 1 of the above-described embodiment in the shapes of the cylindrical body portion 12A and the diameter-reduced portion 13A, but the coating films 522a to 522d2 of the first regions Ar1 to Ar5 in the overcoating process are applied. Since the film thicknesses A to D2 of are set to be the same as those of the above embodiment, the same effect as that of the above embodiment can be obtained.

In the above embodiment, the film thickness C of the coating film 222c in the third coating region Ar3 and the film thickness D2 of the coating film 222d2 in the fifth coating region Ar5 are set to be the same. The film thickness may be increased. That is, as long as D1≦C and D1<D2 are satisfied, either C or D2 may be larger or the same.

In the above-described embodiment, in the overcoating process, the cylindrical body 22 is rotated one or more turns and less than two turns, but the present invention is not limited to this. For example, in the overcoating process, coating may be performed by rotating the cylindrical body 22 two or more times. In this case, since the paint P as the coating film is applied at least twice, the film thickness of the coating film can be increased, and peeling of the printed layer 221 and floating of the coating film can be reliably suppressed.

Furthermore, in the overcoating step, the cylindrical body 22 may be rotated two or more times but less than three times. More preferably, the cylindrical body 22 is rotated 2.0 rounds or more and 2.4 rounds or less. In this case, when the outer peripheral surface 22a of the cylindrical body 22 is coated with the coating material P that forms the coating film, the outer peripheral surface 22a has a double area where the coating material P is applied twice in the second round of the cylindrical body 22, A triple region where the paint P is applied in three layers is formed by the third turn of the cylindrical body 22 . In this case, since the paint that forms the coating film is applied in at least two layers, it is possible to reliably suppress peeling of the printed layer and paint film floating, and since the number of paints that form the coating film does not exceed three layers, it is possible to prevent the necking process from occurring. It is possible to reduce the possibility that the paint film will float and cause roughness.

Also in this case, the film thickness B2 of the coating film 222b in the second coating region Ar2 in the double region is set to 60 mg/dm ² or more and 112 mg/dm ² or less. Further, the numerical range in the triple area where the paint is applied in three layers by the third round of the cylindrical body 22 is, for example, 1.6 to 2.0 times the various numerical ranges in the single area, and the second coating area in the triple area. The thickness of the coating film 222b of Ar2 is 80 mg/dm ² or more and 150 mg/dm ² or less. In addition, since the film thickness of the coating film 222b of the second coating region Ar2 in the triple region tends to be thick, the triple region does not have to be formed.

In the above-described embodiment, the depth and number of the images 421a to 421d2 in each of the regions Ar10 to Ar50 on the outer peripheral surface 42a of the gravure roll 42 are different. Alternatively, only the number of lines may be changed. That is, it is sufficient that the film thicknesses A to D2 of the coating films 222a to 222d2 in the respective coating regions Ar1 to Ar5 can be set within the above numerical range.

In the above embodiment, the outer peripheral surface 22a of the cylinder 22 may be coated with a base coat or a size coat before printing.

In addition, as the bottle can 1, a cylindrical body with a bottom that is integrally molded in advance is formed and printed on its outer surface, but the cylindrical body may include a cylinder that is integrally molded and does not have a bottom. A separately formed bottom may be rolled up around the body.

Reference Signs List 1 1A bottle can 11 bottom portion 111 dome portion 112 heel portion 113 ground portion 12 12A barrel portion 13 13A diameter reduction portion 130 shoulder portion 131 convex curved portion 132 concave curved portion 14 mouth portion 141 bulging portion 142 screw portion 143 curl portion 15 Neck 21 Cup 22 52 Cylindrical body 22a 52a Peripheral surface 221 Printed layer 222 222a 222b 222c 222d1 222d2 522a 522b 522c 522d1 522d2 Coating film 23 First intermediate molded body 231 Small diameter cylindrical part 24 Second intermediate molded body 410 Coating device 2441 Small diameter part Paint supply part 42 Gravure roll 42a Peripheral surface 421a 421b 421c 421d1 421d2 Image line 43 Applicator roll 43a Peripheral surface Ar1 First application area Ar2 Second application area Ar3 Third application area Ar4 Fourth application area Ar5 Fifth application area Ar10 First Area Ar20 Second area Ar30 Third area Ar40 Fourth area Ar50 Fifth area

Claims (7)

A printing step of printing on the outer surface of a cylindrical cylinder having a bottom, an overcoating step of forming a transparent coating film on the outer peripheral surface including the printed layer of the cylindrical body after the printing step, and after the overcoating step The cylindrical body is processed to form a cylindrical cylindrical body, a shoulder continuously formed with the cylindrical body and located on the upper side of the cylindrical body in the can axial direction, and from the upper end of the shoulder to the a necking step of forming a diameter-reduced portion whose diameter decreases toward the upper side in the can axial direction with respect to the cylindrical body portion, and a small-diameter portion extending along the can axis upwardly of the reduced-diameter portion in the can axial direction; a mouth forming step of processing the part to form a mouth having a threaded part,
In the overcoating step, A is the thickness of the coating film in the region that will be the mouth portion of the cylinder, B is the thickness of the coating film in the region that will be the diameter-reduced portion of the cylinder, and the cylinder is A method for manufacturing a bottle can, wherein A<B<D, where D is the film thickness of the coating film in the region to be the body portion in . In the overcoating step, C is the film thickness of the coating film in the region that will be the shoulder portion of the cylindrical body, and D of the film thickness D of the coating film in the region that will be the body portion of the cylindrical body is the bottom side region. 1, wherein D1≦C and D1<D2, where D2 is the film thickness of the coating film of and D1 is the film thickness of the coating film in the region excluding the bottom side region 3. The method for manufacturing the bottle can according to 1. In the overcoating step, the paint that forms the coating film is applied to the outer surface of the cylindrical body by rotating the cylindrical body one or more turns and less than two turns, and the paint is applied only once during the first round of the cylindrical body. A single region with
3. The method according to claim 1 or 2, wherein, of the film thickness B of the coating film in the region to be the diameter-reduced portion, the coating film thickness B1 in the single region is 45 mg/ ^dm2 or more. bottle can manufacturing method. 4. The method for manufacturing bottle cans according to claim 3, wherein the film thickness B1 of the coating film is 80 mg/dm< ² > or less. 3. The method for manufacturing a bottle-can according to claim 1, wherein in the overcoating step, the paint that forms the coating film is applied to the outer surface of the cylindrical body by rotating the cylindrical body two or more times. . In the overcoating step, a double region in which the paint is applied in a double manner is formed by the second round of the cylindrical body, and the double region is 6. The method for manufacturing a bottle can according to any one of claims 3 to 5, wherein the film thickness B2 of the coating film in is set to 60 mg/ ^dm2 or more and 112 mg/ ^dm2 or less. In the overcoating step, the paint that forms the coating film is applied to the outer surface of the cylinder by rotating the cylinder two or more times and less than three times, and the paint is doubled by the second turn of the cylinder. 6. The method for manufacturing a bottle-can according to claim 5, wherein a double region is formed in which the paint is applied to the outer surface of the cylindrical body, and a triple region is formed in which the paint is applied three times on the third circumference of the cylindrical body.

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