JP2015113152A - Ultrathin expanded can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expanded can having small restriction in surface decoration and sufficient strength since a can torso is thinner than ever and an external surface of the can torso is a smooth surface.SOLUTION: A can torso 1 is subjected to expansion processing of expanding its outer diameter over a whole circumference, and a maximum external diameter portion 8 larger than an original diameter before the expansion processing is formed in the center portion in an axial direction of the can torso 1, and a first continuous portion 9 continued from the maximum external diameter portion 8 to an original diameter portion 5 having the same external diameter as an original diameter on one end side of the can torso 1, and a second continuous portion 10 continued from the maximum external diameter portion 8 to an original diameter portion 6 having the same external diameter as an original diameter on the other end side of the can torso 1 are formed in such a shape that the external surface smoothly continues so that the external diameter gradually decreases toward the respective original diameter portions 5 and 6 sides, and the length in the axial direction of the maximum external diameter portion 8 is in a range of 0-30% of the axial length of a can.

Description

  The present invention relates to a metal can in which a metal plate constituting a can body is thinned, and more particularly to a can container in which a metal plate is formed into a cylindrical shape and its butted ends are welded to form a can body. .

  A metal can known as a three-piece can is formed by forming a predetermined rectangular metal plate into a cylindrical shape by a roller or the like, and joining the end portions butted together by seam welding or the like to form a body portion. A lid is attached to both the upper and lower openings. Conventionally, attempts have been made to reduce the thickness of the metal can in order to effectively use resources and reduce costs, and an example thereof is described in Patent Document 1. In the three-piece can described in Patent Document 1, a plurality of beads are formed by denting a central portion of a can body formed by seam welding a surface-treated steel plate into a strip shape. Therefore, since the surface of the can body is divided into two parts by the bead, printing of characters and designs is performed on the upper part and the lower part divided by the bead.

  In contrast to the can described in Patent Document 1, Patent Document 2 discloses a deformed can having a configuration in which a part of the can body is bulged to the outer peripheral side. This deformed can is a metal can in which the can body is expanded to form concave and convex portions directed in the axial direction (up and down direction), and further, inclined concave and convex portions are formed so as to intersect these concave and convex portions. It is.

JP 2000-72143 A Japanese Patent Application Laid-Open No. 2004-289881

  In the three-piece can described in Patent Document 1, since the pressure resistance is increased by providing a bead, the thickness of the surface-treated steel sheet as a material can be reduced to about 0.12 mm to 0.16 mm. It is said that. However, as described in Patent Document 1, since the surface of the can body is divided into upper and lower parts by beads, it is difficult to apply surface decoration such as a pattern that is continuous up and down on the surface of the can body. For example, the design or decoration of a product filled with a can container or contents may be limited or damaged.

  In addition, the modified can described in Patent Document 2 is intended to make the can shape a unique shape or a unique shape, and therefore is not highly versatile with less restrictions on contents, Further, like the metal can described in the above-mentioned Patent Document 1, there is an inconvenience that the uneven portion becomes an obstacle to printing or surface decoration.

  The present invention has been made by paying attention to the above technical problem, and provides an ultra-thin expanded can capable of ensuring strength even when the can body is thinned and at the same time improving printability or decoration. It is intended to do.

  In order to achieve the above-mentioned object, the invention of claim 1 is configured such that a can body around which an upper lid and a lower lid are wound is formed by forming a thin metal plate into a cylindrical shape and welding end portions that are abutted to each other. In the ultra-thin expanded can, the can body is subjected to an expanding process for expanding the outer diameter, and a maximum outer diameter portion larger than the original diameter before the expanding process is formed at a central portion in the axial direction of the can body. And the first continuous portion connected from the maximum outer diameter portion to the original diameter portion having the same outer diameter as the original diameter on the one end portion side of the can body, and the other end portion side of the can body from the maximum outer diameter portion. The second continuous portion connected to the original diameter portion having the same outer diameter as the original diameter has the outer surface smoothly and continuously reduced so that the outer diameter gradually decreases from the maximum outer diameter portion side toward the original diameter portion side. Formed in a shape, the length of the maximum outer diameter portion in the axial direction is And it is characterized in that it is in the 0-30% range of the axial length of the can.

  In this invention, the plate thickness of the thin metal plate is 0.15 mm or less, and the length of the maximum outer diameter portion in the axial direction is the axial direction of the can in which the upper lid and the lower lid are wound around the can body. The length in the axial direction of the first continuous portion and the second continuous portion can be 20 to 50% of the length in the axial direction of the can. .

  Moreover, in this invention, the expansion amount of the outer diameter by the said expand process can be made into 9.8% or less of the said original diameter.

  In addition, in the present invention, the bulging rate, which is the ratio of the expansion amount of the outer diameter by the expanding process to the total length in the axial direction of the first continuous portion and the second continuous portion, is 2.4. % Or more.

  Further, in the present invention, the total length in the axial direction of the maximum outer diameter portion, the first continuous portion, and the second continuous portion is determined in the axial direction of the can in which the upper lid and the lower lid are wound around the can body. It can be 65 to 85% of the length.

  In the present invention, at least one of the first continuous portion and the second continuous portion is a cut surface when the taper surface and the taper surface are smoothly continuous and cut along a plane along the axial direction. May be formed by a convex arc surface having a convex arc shape.

  According to this invention, the central part in the axial direction of the can body is expanded in diameter by expanding, and the outer diameter of the connecting part connected from the maximum outer diameter part to the original diameter part on both ends in the axial direction is continuous. It is formed by a smooth surface that changes with time. In addition, since the length (or width) in the axial direction of the maximum outer diameter portion is set to 0 to 30% of the total length of the can, the pressure resistance that is difficult to deform when the external pressure of the can increases. The strength is increased, and the buckling strength against the axial load can be secured. Further, the expanded can according to the present invention is an enlarged outer diameter of the central portion of the can body over the entire circumference, and its outer surface smoothly continues in both the axial direction and the circumferential direction. Therefore, when surface decoration is applied by printing or film sticking, there is no obstacle caused by the shape of the surface, and the design or merchantability of the can as a product can be improved together with the strength. it can.

It is a front view of the expand can which concerns on this invention.

  The can according to the present invention is a so-called three-piece can in which a beverage such as coffee or green tea is filled, and a lid is wound around each of the upper and lower ends of the can body. In particular, it is a beverage can to which external pressure is applied by retort processing or the like. The can body is manufactured by forming a metal plate into a cylindrical shape and welding the end portions butted against each other. Metal plates constituting the can body are thin steel plates such as hot-dip galvanized steel plate, tin-free steel, tinplate, chrome-plated steel plate, aluminized steel plate, nickel-plated steel plate, turn-plated steel plate, and other various alloy-plated steel plates. And it is an ultra-thin board whose thickness is 0.15 mm or less, for example. In order to avoid the lack of strength associated with the use of such an ultra-thin plate, or to enable the use of an ultra-thin plate without impairing the strength, the can body has an enlarged central portion in the axial direction ( Expanding to swell. An example of the shape is shown in FIG.

  In FIG. 1, reference numeral 1 indicates a can body, and an upper lid 2 is wound around an upper end portion of the can body 1, and a lower lid 3 is wound around a lower end portion. An upper end portion of the can body 1 is a necking portion 4 having a reduced diameter, and a portion continuous to the lower side of the necking portion 4 is an original diameter portion 5 in which the diameter is not increased or decreased. Moreover, the same original diameter part 6 is provided in the lower end part by which the lower cover 3 is wound up. And the part between these upper and lower original diameter parts 5 and 6 is the enlarged diameter part 7 which performed the expansion process.

  The enlarged diameter portion 7 includes a maximum outer diameter portion 8 at the center in the vertical direction of the can body 1, a continuous portion 9 between the maximum outer diameter portion 8 and the upper original diameter portion 5, and the maximum outer diameter portion. It is comprised by three parts with the continuous part 10 between the diameter part 8 and the lower original diameter part 6. FIG. None of these portions 8, 9, 10 is a portion whose diameter in the circumferential direction is expanded outward, but is expanded over the entire circumference, and thus a surface (axis) perpendicular to the central axis The cross-sectional shape when it is cut at a right angle plane is a perfect circle or a shape close thereto. And the height L (the length of the can body 1 in the axial direction) L is 65 to 85% of the height H of the can. If it is less than 65%, there arises a disadvantage that the pressure strength cannot be secured, and if it exceeds 85%, the expanded molded part interferes with the neck molded part at the time of neck molding, resulting in problems such as molding defects.

The maximum outer diameter portion 8 is a portion where the diameter of the can body 1 is greatly expanded, and the expansion ratio is 9.8% or less. The expansion ratio is the ratio of the increase in diameter to the diameter before expansion. When the original diameter is D0 and the diameter of the maximum outer diameter portion 8 is D1, the expansion ratio is ((D1-D0) / D0) × 100
It is. When the diameter expansion rate exceeds 9.8%, the frequency of the can body 1 being broken increases, and stable expanding processing cannot be performed.

Moreover, the lower limit value of the diameter expansion amount is also regulated by the ratio of the diameter expansion amount to the total length (length in the axial direction) of each of the continuous portions 9 and 10. Here, the height of the can (length in the axial direction of the can) is H, the length from the upper end of the can to the upper end of the enlarged diameter portion 7 is Lu, and the lower end of the enlarged diameter portion 7 to the lower end of the can When the length is Lb and the width of the maximum diameter-expanded portion 8 (length in the vertical direction of the can body 1) is C, the ratio of the diameter-expanded amount (D1-D0) to the total length of the continuous portions 9, 10 Is
{(D1-D0) / (H-Lu-Lb-C)} × 100
Thus, if this is called the bulging rate, the bulging rate is 2.4% or more in the present invention. If the swelling rate is less than 2.4%, the can strength (paneling strength) is insufficient. When 2.4% of the bulging rate is replaced with the diameter expansion rate, it is 2.8%. The bulging rate is a value related to the gradient of the enlarged diameter portion 7 with respect to the original diameter portion 9.10. The larger the value, the higher the gradient of the portion that bulges from the original diameter portions 9 and 10 to the outside of the can body 1. Will be big. In other words, when the bulging rate is small, the surface of the can body 1 is close to a simple cylindrical shape. Since the paneling of the can body 1 is a deformation that dents the can body 1, it is considered that the paneling strength increases as the bulging rate increases.

  Further, the width (length) C of the maximum outer diameter portion 8 is 0 to 30% of the height H of the can. The fact that the width C of the maximum outer diameter portion 8 is 0% with respect to the can height H means that the boundary portion between the upper and lower continuous portions 9 and 10 appears as a line, and more than 0% and 30%. If present, the maximum outer diameter portion 8 is a simple cylindrical portion having a constant diameter, and therefore the generatrix of the surface is represented by a straight line parallel to the central axis of the can body 1. The maximum outer diameter portion 8 having a certain width (length) may be referred to as a straight portion. When the width C of the maximum outer diameter portion 8 exceeds 30% of the can height H, a simple cylindrical portion becomes large even if the expansion process is performed, and as described later, the can strength is substantially improved. The effect cannot be obtained.

  The upper and lower continuous portions 9 and 10 are portions where the diameter gradually increases from the original diameter portions 5 and 6 toward the maximum outer diameter portion 8, and the change in the diameter is continuous, and the concave portions along the circumferential direction. There are no local or partial recesses or protrusions such as grooves or protrusions, and therefore the surface is smooth. The continuous portions 9 and 10 may be tapered portions, but the cut surface when cut along a plane along the axial direction is formed by a surface connecting a curved surface having a convex arc shape and a tapered surface. Also good. In this case, it is preferable that the original diameter portions 5 and 6 are tapered surfaces and the maximum outer diameter portion 8 side is an arc surface. In addition, the tangents of adjacent surfaces are substantially coincided with each other so that an excessively bent portion or a bent portion is not generated at the boundary portion between the tapered surface and the arc surface and the boundary portion between the original diameter portions 5 and 6. . And width (length in the up-and-down direction of can body 1) A and B of each continuous part 9 and 10 is set as 20 to 50% of height H of a can, respectively. In addition, the sum (A + B) of these widths A and B is not more than the height L of the enlarged diameter portion 7 ((A + B) ≦ L). These widths A and B have a relationship that when one becomes larger, the other becomes smaller. Therefore, when one of the widths A (B) exceeds the above range, the width is large, or the other width. Due to the small B (A), the paneling strength required for the product cannot be obtained.

  Examples performed to confirm the effects of the present invention will be described below.

The paneling strength and buckling strength of the can according to the present invention were measured together with their strength for the current can (comparative example). The paneling strength is the pressure at which paneling, which is a deformation in which a can with its top and bottom lids tightened, is placed inside the pressurizing chamber, and the internal pressure of the pressurizing chamber is gradually increased and a portion of the can body is recessed. Was measured and used as the paneling strength. The buckling strength was determined by applying axial pressure to the can and measuring the buckled pressure.
The actual product is made of a chrome-plated steel sheet blank with a thickness (t) of 0.15 mm, a width of 108.70 mm, and a length of 158.20 mm. Then, the upper and lower lids were wrapped around this to make a beverage can with a full-capacity of 207 ml. The width and diameter expansion rate of the maximum outer diameter portion 8, the widths of the continuous portions 9 and 10, and the like were set within the above-described ranges. In addition, by performing the expanding process, the plate thickness at the maximum outer diameter portion 8 was reduced to 0.145 mm, and the Rockwell hardness was increased from 61.7 to 65.0.
In addition, the current can as a comparative example is the same material as the actual product, using a blank with a thickness of 0.18 mm, a width of 107.95 mm, and a length of 165.65 mm. A can body was prepared, and upper and lower lids were wound around this to make a beverage can with a full injection capacity of 214 ml.
About these implementation products and comparative examples, empty can paneling strength (required strength: 0.16 MPa or more), actual can paneling strength (required strength: 0.11 MPa or more), and empty can buckling strength (required strength: 1470 N or more) were measured. did. Table 1 shows the measurement results. The empty can paneling strength is the paneling strength when the contents are not filled (the internal pressure is approximately 101.325 kPa at atmospheric pressure), and the actual can paneling strength is the specified amount (190 g). , And the paneling strength of a vacuum of −33 kPa.

  As shown in Table 1, according to the present invention, although each strength is inferior to the comparative example, the empty can paneling strength is 0.164 MPa (> 0.16 MPa), and the actual can paneling strength is 0.128 MPa (> 0.11 MPa), and the empty can buckling strength is 1924N (> 1470N), sufficiently satisfying the required strength. Therefore, according to the present invention, it is possible to reduce the cost by reducing the thickness of the material while sufficiently satisfying the practically required strength. In addition to this, there is no local or partial conspicuous unevenness on the surface of the can body 1 and the entire surface is smooth, which may hinder surface decoration by printing or film sticking. There are no restrictions on decorations such as patterns and characters.

  Moreover, in the can which concerns on this invention, material hardness becomes high by giving an expanding process, and a paneling intensity | strength can be improved in connection with it. Furthermore, since the expanding process applied to the can body in this invention is a process of expanding the diameter over the entire circumference, the roundness of the can body 1 is improved and the curvature of the seam welded part is partially small. For this reason, a part that causes paneling is eliminated, and the paneling strength can be improved in this respect as well.

  Next, an example in which the size range of each part was examined will be shown.

Prepare multiple test cans with different widths C, A, and B of the maximum outer diameter portion 8 and each of the continuous portions 9, 10 and apply paneling by applying a pressure of 0.11 MPa which is the required actual can paneling strength. The presence or absence of occurrence (deformation) was examined. The test can was a can having a nominal diameter of 200 diameters, a plate thickness of 0.15 mm, a can height H of 104.7 mm, and a diameter expansion rate of the maximum outer diameter portion 8 of 4.8%. The results are shown in Table 2. In Table 2, “A dimension” is the width of the upper continuous part 9, “B dimension” is the width of the lower continuous part 10, and “straight” is the width of the maximum outer diameter part 8. Further, “◯” indicates that paneling has not occurred, and “X” indicates that paneling has occurred.

  As is known from the results shown in Table 2, the widths A and B of the continuous portions 9 and 10 are in the range of 20 mm to 50 mm (20% to 50% for the can height H), and the maximum outer diameter. If the width C of the portion 8 is 30 mm or less (30% or less with respect to the can height H), it is recognized that the required actual can paneling strength is satisfied. Although there is an example in which paneling does not occur even when the width of any of the continuous portions 9 and 10 is 15 mm (15% with respect to the can height H) outside the above range, the paneling strength is present. In this invention, the range of the width of each continuous portion 9 and 10 is set to 20 mm to 50 mm (20% to 50% with respect to the can height H).

  Furthermore, the Example which examined the diameter expansion rate which regulates the amount of diameter expansion, and the said bulging rate is shown.

Nominal 200 diameter (original diameter of can body: 50.3 mm) is made of chrome-plated steel plate with a thickness of 0.15 mm, and can height H is 88 mm, 97 mm, 104.7 mm, 109 mm, 133 mm, and each straight part 10 mm, the length Lu from the upper end of the can to the upper end of the enlarged diameter portion, and the length Lb from the lower end of the enlarged diameter portion to the lower end of the can are each 12.35 mm (total length 24.7 mm) As a result, the strength when the bulging rate was varied was measured. The amount of expansion was 1.4 mm, 2.4 mm, 3.0 mm, 4.0 mm, and 5.0 mm. Therefore, the diameter expansion ratio is 2.8%, 4.8%, 6.0%, 8.0%, and 9.9%. Further, the bulging rate was 1.4% at the minimum and 9.4% at the maximum. The results are summarized in Table 3. In Table 3, “Strength ○” indicates that paneling did not occur in the paneling strength test described above, “Strength ×” indicates that paneling occurred in the paneling strength test described above, and “ "X" indicates that a fracture or crack occurred due to the expanding process.

  As can be seen from the results shown in Table 3, when the diameter expansion rate reaches 9.9%, the can body is broken or cracked and becomes a product. Therefore, in this invention, the diameter expansion rate is set to 9.8% or less. Moreover, when the bulging rate mentioned above is as small as about 2.2%, the strength is insufficient. Therefore, in the present invention, the bulging rate is 2.4% or more. This is 2.8% or more, preferably 4.8% in terms of the diameter expansion rate.

  DESCRIPTION OF SYMBOLS 1 ... Can trunk | drum, 2 ... Upper lid, 3 ... Lower lid, 4 ... Necking part, 5, 6 ... Original diameter part, 7 ... Expanded diameter part, 8 ... Maximum outer diameter part, 9, 10 ... Continuous part.

In order to achieve the above-mentioned object, the invention of claim 1 is configured such that a can body around which an upper lid and a lower lid are wound is formed by forming a thin metal plate into a cylindrical shape and welding end portions that are abutted to each other. In the ultra-thin expanded can, an original diameter portion that does not increase or decrease the diameter is formed at each of both end portions in the axial direction of the can body, and a portion between these original diameter portions has an outer diameter around the entire circumference. It is a diameter-expanded portion that has been subjected to an expanding process to be expanded , and the central portion in the axial direction in the diameter-expanded portion is the maximum outer diameter portion that forms a cylindrical shape by having a constant diameter, portion from the maximum outer diameter that connected before Kimoto diameter portion of the one end of the can body, is connected that portion from the contact and the maximum outer diameter before Kimoto diameter portion of the other end of the can body The outer diameter gradually decreases from the maximum outer diameter side toward the original diameter side. That each successive portions together is a continuous portion of the shape and said maximum outer diameter is one that is characterized by being smoothly continuous with a convex arcuate surface.

In this invention, the plate thickness of the thin metal plate is 0.15 mm or less, and the length of the maximum outer diameter portion in the axial direction is the axial direction of the can in which the upper lid and the lower lid are wound around the can body. length is 5% to 30% or less, and pre-Symbol the respective lengths in the axial direction of the continuous section, from 20 to 50% of the length in the axial direction of the can and each successive portions The total length in the axial direction can be 75% or less of the length in the axial direction of the can.

Further, in the present invention, the amount of expansion of the outer diameter by the expanding process is 9.8% or less of the original diameter , and the outer diameter by the expanding process with respect to the total length in the axial direction of each continuous portion bulging ratio is a proportion of expanded amount can be Rukoto and 2.4% or more.

Further, in this invention, the total length of at the maximum outer diameter and the axial direction of the continuous section, the length in the axial direction of the cans tightly wound the upper lid and lower lid to the can body It can be 65 to 85%.

And, in this invention, the pre-Symbol least one continuous portion of the continuous section, when cut in a plane along the axial direction with the tapered surface and the tapered surface to smoothly be consecutive to the maximum outer diameter The cut surface may be formed by a convex arc surface having a convex arc shape.

According to this invention, the central part in the axial direction of the can body is expanded in diameter by expanding, and the outer diameter of the connecting part connected from the maximum outer diameter part to the original diameter part on both ends in the axial direction is continuous. that is formed by a smooth surface that varies manner. That is, since the expanded diameter-expanded portion is composed of a cylindrical maximum outer diameter portion and the continuous portion continuing to both ends thereof , deformation when the external pressure of the can increases. The pressure resistance, which is difficult to do, is increased, and the buckling strength against the load in the axial direction can be secured. Further, the expanded can according to the present invention is an enlarged outer diameter of the central portion of the can body over the entire circumference, and its outer surface smoothly continues in both the axial direction and the circumferential direction. Therefore, when surface decoration is applied by printing or film sticking, there is no obstacle caused by the shape of the surface, and the design or merchantability of the can as a product can be improved together with the strength. it can.

In order to achieve the above-mentioned object, the invention of claim 1 is configured such that a can body around which an upper lid and a lower lid are wound is formed by forming a thin metal plate into a cylindrical shape and welding end portions that are abutted to each other. In the ultrathin expanded can, the thin metal plate is a steel plate having a thickness of 0.15 mm or less, and an original diameter portion in which the diameter is not increased or decreased is formed at each of both end portions in the axial direction of the can body. In addition, a portion between these original diameter portions is an enlarged diameter portion subjected to an expanding process that expands the outer diameter over the entire circumference, and a central portion in the axial direction of the enlarged diameter portion is a diameter. Is the maximum outer diameter portion having a cylindrical shape, and the length in the axial direction of the maximum outer diameter portion is the length in the axial direction of the can in which the upper lid and the lower lid are wound around the can body. 30% or less than 5% of the, from the maximum outer diameter The portion connected to the original diameter portion on one end side of the recording drum, and the portion connected to the original diameter portion on the other end portion side of the can barrel from the maximum outer diameter portion to the original outer diameter portion side. Consecutive portions of which the outer diameter gradually decreases toward the original diameter portion side, and each continuous portion and the maximum outer diameter portion are smoothly continuous by the convex arc surface, and the axial direction of each continuous portion is Each length is 20 to 50% of the length in the axial direction of the can, and the total length in the axial direction of each continuous portion is 75% or less of the length in the axial direction of the can. It is characterized by this.

According to this invention, the central part in the axial direction of the can body is expanded in diameter by expanding, and the continuous part connected from the maximum outer diameter part to the original diameter part on both ends in the axial direction has an outer diameter. It is formed by a smooth surface that changes continuously . Moreover, the length (or width) of the maximum outer diameter portion in the axial direction is 5% or more and 30% or less of the total length of the can, and the length of each continuous portion in the axial direction is the axial direction of the can. Since the total length in the axial direction of each continuous part is set to 75% or less of the length in the axial direction of the can , the external pressure of the can is increased. In this case, the pressure resistance, which is difficult to deform, increases, and the buckling strength against the axial load can be secured. Further, the expanded can according to the present invention is an enlarged outer diameter of the central portion of the can body over the entire circumference, and its outer surface smoothly continues in both the axial direction and the circumferential direction. Therefore, when surface decoration is applied by printing or film sticking, there is no obstacle caused by the shape of the surface, and the design or merchantability of the can as a product can be improved together with the strength. it can.

Claims (6)

In the ultra-thin expandable can, in which the can body around which the upper cover and the lower cover are tightened is formed by forming a thin metal plate into a cylindrical shape and welding the butted ends together,
The can body is subjected to an expanding process for expanding the outer diameter over the entire circumference, and a maximum outer diameter portion larger than the original diameter before the expanding process is formed in a central portion in the axial direction of the can body. With
A first continuous portion connected from the maximum outer diameter portion to an original diameter portion having the same outer diameter as the original diameter on one end portion side of the can body, and the original diameter on the other end portion side of the can body from the maximum outer diameter portion. The second continuous portion connected to the original diameter portion having the same outer diameter as the outer surface is formed in a shape in which the outer surface is smoothly continuous so that the outer diameter gradually decreases from the maximum outer diameter portion side toward the original diameter portion side. And
An ultrathin expandable can characterized in that the length of the maximum outer diameter portion in the axial direction is in the range of 0 to 30% of the axial length of the can. The thickness of the thin metal plate is 0.15 mm or less,
The length in the axial direction of the maximum outer diameter portion is 30% or less of the length in the axial direction of the can obtained by winding the upper lid and the lower lid around the can body, and the first continuous portion and the second continuous portion 2. The ultrathin expandable can according to claim 1, wherein the length of each continuous portion in the axial direction is 20 to 50% of the length in the axial direction of the can.   The ultrathin expandable can according to claim 1 or 2, wherein the expansion amount of the outer diameter by the expanding process is 9.8% or less of the original diameter.   The bulging rate, which is a ratio of the expansion amount of the outer diameter by the expanding process, to the total length in the axial direction of the first continuous part and the second continuous part is 2.4% or more. The ultrathin expanding can according to any one of 1 to 3.   The total length in the axial direction of the maximum outer diameter portion, the first continuous portion, and the second continuous portion is 65 to 85 of the length in the axial direction of the can in which the upper lid and the lower lid are wound around the can body. The ultrathin expandable can according to any one of claims 1 to 4, wherein the can is%. At least one of the first continuous portion and the second continuous portion is a convex surface in which a cut surface when the taper surface and the taper surface are smoothly continuous and cut along a plane along the axial direction is a convex arc. The ultrathin expanded can according to any one of claims 1 to 5, wherein the can is formed by an arc surface.