Straw and method for manufacturing straw

Abstract

This straw comprises a cylindrical winding part on which a rectangular metal foil is wound. Both ends of the metal foil in the longitudinal direction of the straw are folded back. This method is a method for manufacturing a straw comprising cylindrical winding part on which a rectangular metal foil is wound. In the manufacturing method, both ends of the metal foil in the longitudinal direction of the straw are folded back. A core part, which is a part of the metal foil, is sandwiched by a first winding core and a second winding core arranged along the longitudinal direction. A part of the metal foil excluding the core part is wound around the first winding core and the second winding core.

Description

Straws and straw manufacturing methods CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This international application claims priority based on Japanese Patent Application No. 2024-114918, filed with the Japan Patent Office on July 18, 2024, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to straws and methods of making straws.

[0003] Patent Document 1 describes a straw manufactured by wrapping a soft aluminum foil material.

[0004] JP 2024-46015 A

[0005] Straws are sometimes used as follows: The opening of a container containing a beverage is covered with plastic food wrap. The user pierces the plastic food wrap with the end of the straw, creating a hole in the plastic food wrap. The straw is then inserted into the container through the hole. The user can then drink the beverage through the straw.

[0006] When straws made by wrapping soft aluminum foil or other metal foil around the straw are used as described above, the end of the straw may become deformed when trying to break through the plastic food packaging, making it difficult for the user to drink a beverage through the straw.

[0007] In one aspect of the present disclosure, it is preferable to provide a straw and a method for manufacturing a straw whose end is less likely to deform.

[0008] One aspect of the present disclosure is a straw having a cylindrically wound portion formed by winding a rectangular metal foil, wherein both longitudinal ends of the metal foil are folded back. The straw according to one aspect of the present disclosure has ends that are resistant to deformation.

[0009] Another aspect of the present disclosure is a method for manufacturing a straw having a cylindrically wound portion formed by winding a rectangular metal foil, in which both longitudinal ends of the metal foil are folded back, a core portion that is a part of the metal foil is sandwiched between a first winding core and a second winding core that are arranged along the longitudinal direction, and the metal foil excluding the core portion is wound around the first winding core and the second winding core. According to this straw manufacturing method, which is another aspect of the present disclosure, a straw whose ends are less likely to deform can be manufactured.

[0010] FIG. 2 is an explanatory diagram showing a step of folding back an end of the metal foil. FIG. 2 is an explanatory diagram showing a step of winding the metal foil around the core in the first embodiment. The upper part of FIG. 2 is a plan view, and the lower part is a drawing seen from the axial direction of the core. FIG. 3 is an explanatory diagram showing a step of winding the metal foil around the core in the second embodiment. The upper part of FIG. 3 is a plan view, and the lower part is a drawing seen from the axial direction of the core. FIG. 4 is an explanatory diagram showing a step of winding the metal foil around the core in the third embodiment. FIG. 4 is a plan view, and the lower part is a drawing seen from the axial direction of the core. FIG. 5 is an explanatory diagram showing a step of winding the metal foil around the core in the fourth embodiment. FIG. 6 is an explanatory diagram showing a step of winding the metal foil around the core in the fifth embodiment. FIG. 6 is a plan view, and the lower part is a drawing seen from the axial direction of the core. FIGS. 7A and 7B are photographs of the end faces of straws produced in the examples. FIG. 8A is a photograph showing a method for evaluating piercing resistance. Fig. 8B is a photograph of the surface of agar when a commercially available plastic straw is used. Fig. 8C is a photograph of the surface of agar when straw R1 is used. Fig. 8D is a photograph of the surface of agar when straw 1A is used. Fig. 9A is an explanatory diagram showing the shape of a hiragana character that can be written in one stroke. Fig. 9B is an explanatory diagram showing the shape of a katakana character that can be written in one stroke.

[0011] Illustrative embodiments of the present disclosure will be described with reference to the drawings. First Embodiment 1. Manufacturing Method of Straw 1A A manufacturing method of straw 1A will be described with reference to FIGS. 1 and 2. As shown in S1-1 of FIG. 1, a rectangular metal foil 3 is prepared. The rectangle corresponds to a rectangle. The longitudinal direction of the metal foil 3 is defined as the longitudinal direction L. The lateral direction of the metal foil 3 is defined as the lateral direction W. The longitudinal direction L is also the longitudinal direction of straw 1A. Both end faces of the metal foil 3 in the longitudinal direction L are defined as end faces 5 and 7. Both end faces of the metal foil 3 in the lateral direction W are defined as end faces 9 and 11.

[0012] The thickness of the metal foil 3 is, for example, 50 μm to 100 μm. When the thickness of the metal foil 3 is within this range, it is easy to maintain a cylindrical shape when rolled up into a straw shape. The metal foil 3 is, for example, a soft aluminum foil. The surface roughness Ra of the metal foil 3 is, for example, 10 μm or more. The method for measuring the surface roughness Ra is as follows.

[0013] Measuring equipment: Contact roughness meter: Surtronic S-116 Measuring method: Complies with general (new JIS) Cutoff: 0.8 mm Measuring length: 3 mm Filter: Digital (Gaussian) If the surface roughness Ra of the metal foil 3 is 10 μm or more, foaming can be promoted when the straw 1A is immersed in carbonated water.

[0014] In the metal foil 3, a corner 10 between the end face 5 and the end face 9 is cut out and has an arc shape. In the metal foil 3, a corner 12 between the end face 7 and the end face 9 is also cut out and has an arc shape. The length A of the metal foil 3 in the longitudinal direction L Ｌ is, for example, 150 mm or more and 250 mm or less.

[0015] The strip-shaped portion of the metal foil 3 that is on the side of the end face 5 and extends along the end face 5 is referred to as the end face 6. The strip-shaped portion of the metal foil 3 that is on the side of the end face 7 and extends along the end face 7 is referred to as the end face 8. The end face 6 and the end face 8 are both ends of the metal foil 3 in the longitudinal direction L. The shape of the end face 6 and the end face 8 is, for example, strip-shaped.

[0016] Length A of the end 6 and end 8 in the short direction W Ｗare, for example, 30 mm or more and 320 mm or less. The width B of each of the end portions 6 and 8 in the longitudinal direction L is, for example, 3 mm or more and 10 mm or less. The width B is, for example, constant regardless of the position in the short-side direction W.

[0017] Next, as shown in S1-2 of FIG. 1 , the end 6 and the end 8 are each folded back. The end 6 is folded back at the folding line 21. The folding line 21 is, for example, a straight line parallel to the end face 5. The folded back end 6 overlaps a portion of the metal foil 3 adjacent to the end 6. The distance between the end face 5 and the folding line 21 is equal to the width B. After the end 6 is folded back, the folding line 21 and the corner 10 become the end face of the metal foil 3 in the longitudinal direction L. The folding line 21 and the corner 10 are adjacent to each other, and there is no step at the boundary between them.

[0018] The end 8 is folded back at the folding line 23. The folding line 23 is, for example, a straight line parallel to the end face 7. The folded back end 8 overlaps a portion of the metal foil 3 adjacent to the end 8. The distance between the end face 7 and the folding line 23 is equal to the width B. After the end 8 is folded back, the folding line 23 and the corner 12 become the end face of the metal foil 3 in the longitudinal direction L. The folding line 23 and the corner 12 are adjacent to each other, and there is no step at the boundary between them.

[0019] The end face of the metal foil 3 in the longitudinal direction L is composed of fold lines 21, 23 and arc-shaped corners 10, 12. There is no step at the boundary between the fold line 21 and the corner 10. There is also no step at the boundary between the fold line 23 and the corner 12.

[0020] Therefore, all of the end faces of the metal foil 3 in the longitudinal direction L are either folded portions or arc-shaped portions of the metal foil 3. The end faces of the metal foil 3 in the longitudinal direction L become the end faces of the straw 1A. Because the end faces of the metal foil 3 in the longitudinal direction L are configured as described above, it is possible to prevent the end faces of the straw 1A from injuring the user's mouth, etc.

[0021] Next, as shown in S1-3 of FIG. 2 , the winding core 15 is placed on top of the metal foil 3. The winding core 15 is a cylindrical member. The diameter of the winding core 15 is, for example, 3 mm or more and 10 mm or less. The axial direction of the winding core 15 is along the longitudinal direction L. For example, the axial direction of the winding core 15 is parallel to the longitudinal direction L. In the short direction W, the winding core 15 is positioned so as to overlap the end surface 11. The winding core 15 is placed on the surface of the metal foil 3 where the folded end portions 6 and 8 are present. The winding core 15 is in contact with the end portions 6 and 8.

[0022] Next, as shown in S1-4 to S1-7 in Fig. 2, with the metal foil 3 in close contact with the outer peripheral surface of the winding core 15, the winding core 15 is rolled in the direction toward the end surface 9. As the winding core 15 is rolled, the metal foil 3 is wound around the winding core 15. At this time, the metal foil 3 is wound so that the folded-back end portions 6 and 8 are on the inside.

[0023] Eventually, as shown in S1-7 of Fig. 2, the entire metal foil 3 is wound around the winding core 15. As a result, the winding portion 17 is formed. The winding portion 17 is a cylindrical member formed by winding the metal foil 3. The number of turns of the metal foil 3 wound around the winding portion 17 is, for example, 2 or more and 10 or less. Finally, as shown in S1-8 of Fig. 2, the winding core 15 is removed from the winding portion 17. Through the above steps, the straw 1A made up of the winding portion 17 is completed.

[0024] 2. Effects of Straw 1A (1A) Straw 1A has folded ends 6 and 8. Therefore, when trying to break through plastic food packaging with the ends of straw 1A, the ends of straw 1A are less likely to deform.

[0025] (1B) In straw 1A, end 6 and end 8 are folded back. This prevents the end of straw 1A from injuring the user's mouth, etc. Second Embodiment 1. Differences from First Embodiment Since the basic configuration of the second embodiment is the same as that of the first embodiment, differences will be explained below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding explanation will be referred to.

[0026] In the first embodiment described above, the winding core 15 was an integral member. In contrast, in the second embodiment, as shown in FIG. 3 , the winding core 15 is a member that can be separated into a first winding core 15A and a second winding core 15B, which is different from the first embodiment. The first winding core 15A and the second winding core 15B each have a shape that is a half cylinder. The shape of the joint surface 18 where the first winding core 15A and the second winding core 15B are joined is linear when viewed in the axial direction of the winding core 15. The joint surface 18 extends from one end face of the winding core 15 to the opposite end face along the axial direction of the winding core 15.

[0027] In the first embodiment, when the winding core 15 is set on the metal foil 3, the winding core 15 is placed on top of the metal foil 3, as shown in S1-3 of Fig. 2. In contrast, in the second embodiment, as shown in S2-3 of Fig. 3, the first winding core 15A and the second winding core 15B sandwich the portion of the metal foil 3 on the side of the end face 11. The sandwiched metal foil 3 contacts the joining surface 18. The sandwiched metal foil 3 will later become the core portion 19. The distance between the portion of the metal foil 3 sandwiched between the first winding core 15A and the second winding core 15B and the end face 11 (hereinafter referred to as the end face-to-winding core distance) is 0 mm.

[0028] Next, as shown in S2-4 to S2-7 in Fig. 3, the winding core 15 is rolled in the direction toward the end face 9. As the winding core 15 is rolled, the metal foil 3 is wound around the winding core 15 except for the portion sandwiched between the first winding core 15A and the second winding core 15B. At this time, the metal foil 3 is wound so that the folded end portions 6 and 8 are on the inside.

[0029] 3, the entire metal foil 3 except for the portion sandwiched between the first winding core 15A and the second winding core 15B is wound around the winding core 15. As a result, the wound portion 17 is formed. The wound portion 17 is a cylindrical member formed by winding the metal foil 3.

[0030] Finally, as shown in S2-8 of FIG. 3, the core 15 is removed from the winding section 17. The portion of the metal foil 3 that was previously sandwiched between the first winding core 15A and the second winding core 15B becomes the core 19. The core 19 is made of a part of the metal foil 3 and is a member that is placed inside the winding section 17. The shape of the core 19 is linear when viewed from the axial direction of the winding section 17. The linear shape corresponds to a shape that can be written with one stroke. A shape that can be written with one stroke is a shape that can be drawn with one stroke without ever removing the writing implement from the plane. An example of a shape that can be written with one stroke is a shape in which the lines do not intersect. Through the above steps, a straw 1B comprising the winding section 17 and the core 19 is completed.

[0031] 2. Effects of the Straw 1B According to the second embodiment described above in detail, in addition to the effects of the first embodiment described above, the following effects are also achieved.

[0032] (2A) The straw 1B has a core 19. Therefore, when an attempt is made to pierce the plastic wrap for food packaging with the end of the straw 1B, the end of the straw 1B is even less likely to deform. <Third Embodiment> 1. Differences from the Second Embodiment The third embodiment has the same basic configuration as the second embodiment, so the differences will be explained below. Note that the same symbols as those in the second embodiment indicate the same configuration, and reference is made to the preceding explanation.

[0033] In the second embodiment described above, the shape of the joint surface 18 where the first winding core 15A and the second winding core 15B are joined is linear when viewed in the axial direction of the winding core 15. In contrast, in the third embodiment, as shown in Fig. 4, the shape of the joint surface 18 is M-shaped when viewed in the axial direction of the winding core 15.

[0034] In the third embodiment, as shown in S3-3 in Fig. 4, the first winding core 15A and the second winding core 15B sandwich the portion of the metal foil 3 on the side of the end face 11. The sandwiched metal foil 3 contacts the joining surface 18. When viewed from the axial direction of the winding core 15, the shape of the sandwiched metal foil 3 is the same as the joining surface 18 (i.e., M-shaped). The sandwiched metal foil 3 will later become the core portion 19. The distance between the end face and the winding core is 0 mm.

[0035] Next, as shown in S3-4 to S3-7 in Fig. 4, the winding core 15 is rolled in the direction toward the end face 9. As the winding core 15 is rolled, the metal foil 3 is wound around the winding core 15 except for the portion sandwiched between the first winding core 15A and the second winding core 15B. At this time, the metal foil 3 is wound so that the folded end portions 6 and 8 are on the inside.

[0036] 4, the entire metal foil 3, excluding the portion sandwiched between the first winding core 15A and the second winding core 15B, is wound around the winding core 15. As a result, the wound portion 17 is formed. The wound portion 17 is a cylindrical member formed by winding the metal foil 3.

[0037] Finally, as shown in S3-8 of FIG. 4, the winding core 15 is removed from the winding unit 17. The portion of the metal foil 3 that was previously sandwiched between the first winding core 15A and the second winding core 15B becomes the core 19. The core 19 is made of a part of the metal foil 3 and is a member that is placed inside the winding unit 17. The shape of the core 19 is M-shaped when viewed from the axial direction of the winding unit 17. The M-shape corresponds to a shape that can be drawn in one stroke. Through the above steps, a straw 1C including the winding unit 17 and the core 19 is completed.

[0038] 2. Effects of the straw 1C The third embodiment described above achieves the effects of the second embodiment. <Fourth embodiment> 1. Differences from the second embodiment The fourth embodiment has the same basic configuration as the second embodiment, so the differences will be explained below. Note that the same symbols as the second embodiment indicate the same configuration, and the preceding explanation will be referred to.

[0039] In the second embodiment described above, the distance between the end face and the winding core was 0 mm, whereas in the fourth embodiment, the distance between the end face and the winding core is set to approximately 30 mm, as shown in S4-3 of FIG.

[0040] 5, the winding core 15 is rolled in the direction toward the end face 9. As the winding core 15 is rolled, the metal foil 3 is wound around the winding core 15 except for the portion sandwiched between the first winding core 15A and the second winding core 15B. At this time, the metal foil 3 is wound so that the folded end portions 6 and 8 are on the inside.

[0041] 5, the entire metal foil 3, excluding the portion sandwiched between the first winding core 15A and the second winding core 15B, is wound around the winding core 15. As a result, the wound portion 17 is formed. The wound portion 17 is a cylindrical member formed by winding the metal foil 3.

[0042] Finally, as shown in S4-7 of Figure 5, the winding core 15 is removed from the winding unit 17. The portion of the metal foil 3 that was previously sandwiched between the first winding core 15A and the second winding core 15B becomes the core 19. The core 19 is made of a part of the metal foil 3 and is a member that is placed inside the winding unit 17. The shape of the core 19 is linear when viewed from the axial direction of the winding unit 17. The linear shape corresponds to a shape that can be drawn in one stroke. Through the above steps, a straw 1D comprising the winding unit 17 and the core 19 is completed.

[0043] 2. Effects of the straw 1D The fourth embodiment described above achieves the effects of the second embodiment. <Fifth embodiment> 1. Differences from the third embodiment The fifth embodiment has the same basic configuration as the third embodiment, so the differences will be explained below. Note that the same symbols as the third embodiment indicate the same configuration, and the preceding explanation will be referred to.

[0044] In the third embodiment described above, the distance between the end face and the winding core is 0 mm, whereas in the fifth embodiment, the distance between the end face and the winding core is set to about 30 mm.

[0045] Next, as shown in S5-4 to S5-6 in Fig. 6, the winding core 15 is rolled in the direction toward the end face 9. As the winding core 15 is rolled, the metal foil 3 is wound around the winding core 15 except for the portion sandwiched between the first winding core 15A and the second winding core 15B. At this time, the metal foil 3 is wound so that the folded-back end portions 6 and 8 are on the inside.

[0046] 6, the entire metal foil 3, excluding the portion sandwiched between the first winding core 15A and the second winding core 15B, is wound around the winding core 15. As a result, the wound portion 17 is formed. The wound portion 17 is a cylindrical member formed by winding the metal foil 3.

[0047] Finally, as shown in S5-7 of Figure 6, the winding core 15 is removed from the winding unit 17. The portion of the metal foil 3 that was previously sandwiched between the first winding core 15A and the second winding core 15B becomes the core 19. The core 19 is made of a part of the metal foil 3 and is a member that is placed inside the winding unit 17. The shape of the core 19 is M-shaped when viewed from the axial direction of the winding unit 17. The M-shape corresponds to a shape that can be drawn in one stroke. Through the above steps, a straw 1E including the winding unit 17 and the core 19 is completed.

[0048] 2. Effects of Straw 1E According to the fifth embodiment described above in detail, the effects of the third embodiment described above are achieved. <Example> 1. Manufacturing of Straws 1A to 1E Straws 1A to 1E were manufactured using the methods described in the first to fifth embodiments. Figure 7A shows a photograph of the end faces of straws 1A, 1B, and 1D. Figure 7B shows a photograph of the end faces of straws 1A, 1C, and 1E. Straws 1A to 1E had the following in common.

[0049] Material of metal foil 3: soft aluminum foil Thickness of metal foil 3: 50 μm Surface roughness Ra of metal foil 3: 0.2 μm Length A of metal foil 3 in longitudinal direction L Ｌ Length A of the end portion 6 and the end portion 8 in the short direction W: 220 mm Ｗ: 80 mm Length of metal foil 3 in short direction W: 85 mm Width B of end 6, end 8 in longitudinal direction L: 5 mm Diameter of winding core 15: 6 mm The number of turns of metal foil 3 wound around winding portion 17 was 4.5 turns for straw 1A, 4 turns for straw 1B, 3.5 turns for straw 1C, and 2.5 turns for straw 1D and straw 1E.

[0050] Additionally, straws RA, RB, and RC were manufactured as comparative examples. Straw RA was basically the same as straw 1A, but end portions 6 and 8 were not folded over. Straw RB was basically the same as straw 1B, but end portions 6 and 8 were not folded over. Straw RC was basically the same as straw 1C, but end portions 6 and 8 were not folded over.

[0051] 2. Evaluation of the ease of deformation of the end portion Straws 1A to 1E and straws RA to RC were evaluated as follows. A cylindrical container with an opening at the top was prepared. The inner diameter of the opening was 70 mm. The entire opening was covered with one sheet or N layers of plastic wrap for food packaging. N was a natural number between 2 and 6.

[0052] Next, the longitudinal end of the straw to be evaluated was pierced into the plastic food wrap. During this operation, the axial direction of the straw was perpendicular to the surface of the plastic food wrap. After that, the straw was evaluated based on the condition of the plastic food wrap and the straw according to the following criteria.

[0053] GA: The straw was able to break through the plastic food packaging, and the end of the straw was not deformed.

[0054] GB: The plastic food packaging was broken through, and the end of the straw was deformed enough to allow the beverage to be drunk through the straw.

[0055] GC: The plastic food wrap could not be broken through, or the end of the straw was deformed to the extent that it was not possible to drink from the straw.

[0056] The evaluation results are shown in Table 1. The rows labeled "1 sheet" to "6 sheets" in Table 1 indicate the evaluation results when the number of sheets of food packaging plastic wrap was 1 to 6, respectively. The "distance between end face and winding core" for straws 1A and RA refers to the distance between winding core 15 and end face 11 when winding core 15 was first set.

[0057]

[0058] As shown in Table 1, when straws 1A to 1E were used to break through plastic food packaging wrap, the end of the straw was less likely to deform. When straws 1B to 1E, which had core 19, were used to break through plastic food packaging wrap, the end of the straw was even less likely to deform.

[0059] In contrast, with straws RA to RC, in which ends 6 and 8 were not folded over, the ends of the straws were easily deformed when an attempt was made to break through the plastic wrap used for packaging food with the ends of the straws.

[0060] 3. Evaluation of Piercing Efficiency The following evaluation was performed on straws 1A and 1R. Additionally, as a comparative example, a similar evaluation was performed on a commercially available plastic straw. Agar was placed in a container with an opening at the top. As shown in FIG. 8A, the straw was placed above the container. At this time, the axial direction of the straw was vertical. Next, the straw was gradually lowered, and a range of 1.5 mm from the bottom end of the straw was pierced into the agar. Next, the straw was pulled up. The surface of the agar was then observed.

[0061] Figure 8B shows a photograph of the agar surface when a commercially available plastic straw was used. Figure 8C shows a photograph of the agar surface when straw R1 was used. Figure 8D shows a photograph of the agar surface when straw 1A was used. When using the commercially available plastic straw and straw R1, indentations were observed on the agar surface. When straw 1A was used, no indentations were observed on the agar surface.

[0062] The evaluation results show that straw 1A is less likely to injure the user's mouth or other parts with its ends. This is because straw 1A has folded ends 6 and 8. <Other Embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be practiced in various modifications.

[0063] (1) The shape of the core portion 19 may be a shape other than a straight line or an M-shape. When viewed from the axial direction of the winding portion 17, the shape of the core portion 19 is, for example, a shape that can be written in one stroke. Examples of shapes that can be written in one stroke include the alphabet characters I, J, L, N, S, U, V, W, Z, B, C, D, G, O, P, and R. Examples of shapes that can be written in one stroke include the katakana characters ko, no, fu, he, re, ku, ro, and wa, as shown in FIG. 9A. Examples of shapes that can be written in one stroke include the hiragana characters ku, shi, tsu, te, hi, he, ro, and n, as shown in FIG. 9B. Examples of shapes that can be written in one stroke include the Arabic numerals 1, 2, 3, 5, 7, 0, 6, and 9. Shapes that can be written in one stroke may also be symbols.

[0064] (2) The strip-shaped portion of the metal foil 3 along the edge surface 9 may be folded back. In this case, the edge surface 9 can be prevented from injuring the user's hand.

[0065] (3) The distance between the end face and the winding core may be smaller than 30 mm or may be larger than 30 mm.

[0066] (4) The function of one component in each of the above embodiments may be shared among multiple components, or the functions of multiple components may be performed by one component. Also, part of the configuration of each of the above embodiments may be omitted. Furthermore, at least part of the configuration of each of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0067] (5) In addition to the straw described above, the present disclosure can be realized in various forms, such as a system including the straw as a component, a tubular metal foil, and a method for manufacturing a tubular metal foil. [Technical Concepts Disclosed in this Specification] [Item 1] A straw comprising a tubular wound portion formed by winding rectangular metal foil, wherein both ends of the metal foil in the longitudinal direction of the straw are folded back. [Item 2] The straw according to item 1, further comprising a core portion formed from a portion of the metal foil and disposed inside the wound portion. [Item 3] The straw according to item 2, wherein, when viewed in the axial direction of the wound portion, the shape of the core portion is such that it can be drawn in one stroke. [Item 4] The straw according to any one of items 1 to 3, wherein the metal foil is soft aluminum foil having a thickness of 50 μm to 100 μm. [Item 5] The straw according to any one of items 1 to 4, wherein the metal foil has a surface roughness Ra of 10 μm or more. [Item 6] The straw according to any one of items 1 to 5, wherein corners of the rectangular metal foil have an arc-shaped shape, the both ends are folded back at folding lines, and end faces of the metal foil in the longitudinal direction are composed of the folding lines and the arc-shaped corners. [Item 7] A method for manufacturing a straw having a cylindrical wound portion formed by winding rectangular metal foil, wherein both ends of the metal foil in the longitudinal direction of the straw are folded back, a core portion that is part of the metal foil is sandwiched between a first winding core and a second winding core that are arranged along the longitudinal direction, and a portion of the metal foil excluding the core portion is wound around the first winding core and the second winding core. [Item 8] A method for manufacturing a straw according to Item 7, wherein the corners of the rectangular metal foil have an arc shape, the two ends are folded back at folding lines, and the end faces of the metal foil in the longitudinal direction are formed by the folding lines and the arc-shaped corners.

[0068] 1A to 1E, RA to RC... straw, 3... metal foil, 5, 7, 9, 11... end surface, 6, 8... end portion, 15... winding core, 15A... first winding core, 15B... second winding core, 17... winding portion, 18... joining surface, 19... core portion, 21, 23... fold line

Claims

1. A straw having a cylindrically wound portion formed by winding a rectangular metal foil, wherein both ends of the metal foil in the longitudinal direction of the straw are folded back.

2. The straw according to claim 1, further comprising a core portion formed from a part of the metal foil and disposed inside the wound portion.

3. A straw as claimed in claim 2, wherein the shape of the core portion when viewed in the axial direction of the wound portion is such that it can be drawn in one stroke.

4. A straw according to any one of claims 1 to 3, wherein the metal foil is a soft aluminum foil having a thickness of 50 μm or more and 100 μm or less.

5. A straw according to any one of claims 1 to 3, wherein the surface roughness Ra of the metal foil is 10 μm or more.

6. A straw as claimed in any one of claims 1 to 3, wherein the corners of the rectangular metal foil have an arcuate shape, the two end portions are folded back at folding lines, and the end faces of the metal foil in the longitudinal direction are formed by the folding lines and the arcuate corners.

7. A method for manufacturing a straw having a cylindrically wound portion wound around a rectangular metal foil, comprising: folding back both longitudinal ends of the metal foil; sandwiching a core portion, which is a part of the metal foil, between a first winding core and a second winding core arranged along the longitudinal direction; and winding the metal foil, excluding the core portion, around the first winding core and the second winding core.

8. A method for manufacturing a straw as described in claim 7, wherein the corners of the rectangular metal foil have an arc-shaped configuration, the two ends are folded back at folding lines, and the end faces of the metal foil in the longitudinal direction are formed by the folding lines and the arc-shaped corners.

Images