Container and method of manufacturing a container

Abstract

The container has a cylindrical body portion, a flange portion, and a bottom portion. The body portion is formed by bonding paper covered with a thermoplastic resin, and has a side seam portion on a side surface. The flange portion is formed by rolling up paper at one end of the body portion, and is bonded to a lid material by heat sealing. The bottom portion is formed at the other end of the body portion. The flange portion has a stepped portion of a prescribed height and a prescribed width at an outer peripheral end of an upper surface.

Description

Technical Field

[0001] This invention relates to containers for food and beverages and methods for manufacturing the same. Background Technology

[0002] In the past, as containers for food and beverages (paper cups), containers with the opening end sealed by a thin film-like lid were widely used. These containers had a cylindrical body and a bottom made of sheet material, respectively. The cylindrical body had a side seam (fitting part), and the bottom was installed on the inside of the cylindrical body.

[0003] The container has an opening with a flange facing outwards. After the container is filled with beverages or other contents, the lid is bonded to the flange by means of heat sealing, for example.

[0004] Patent Document 1 describes the formation of the aforementioned flange (cup edge) with a circular (curled) cross-section.

[0005] Patent document 2 below describes how the aforementioned flange (cup mouth) is pressed from the top and bottom directions to form a flat shape.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 2008-507458;

[0009] Patent document 2: Japanese Patent Application Publication No. 2004-042987. Summary of the Invention

[0010] The problem the invention aims to solve

[0011] However, when the flange is in a curled shape as described in Patent Document 1 above, the flange sometimes deforms when the cover material is sealed, and the outer diameter of the opening changes, which leads to a poor fit of the cover (top cover) that fits with the flange.

[0012] Furthermore, when the flange portion has a curled shape as described in Patent Document 1 above, or when the flange portion has a pressed flat shape as described in Patent Document 2 above, sometimes the flange portion deforms when the cover material is opened, resulting in unstable opening. In addition, the fit of the cover deteriorates as described above.

[0013] In view of the above situation, the object of the present invention is to provide a container and a method for manufacturing the container, which can suppress deformation of the flange portion when the lid is sealed and when it is opened without changing the sealing conditions of the lid material.

[0014] Solution for solving the problem

[0015] To achieve the above objectives, one aspect of the present invention relates to a container having a cylindrical body, a flange, and a bottom. The cylindrical body is formed by bonding paper material coated with thermoplastic resin, and has side seams on its sides. The flange is formed at one end of the cylindrical body from rolled-up paper material and is bonded to a cover material by heat sealing. The bottom is formed at the other end of the cylindrical body. The flange has a stepped portion of a predetermined height and a predetermined width at its outer peripheral end on its upper surface.

[0016] According to this structure, by providing a stepped portion at the outer peripheral end of the upper surface of the flange, the sealing head does not contact the stepped portion when the cover is sealed, but only contacts the inner side of the flange, thereby preventing deformation of the flange. Moreover, when the cover is opened, the point of application of the opening force relative to the fulcrum of the opening force (the boundary between the cylinder and the flange) becomes more inward than the outer peripheral end of the flange (the starting point of the stepped portion), so the torque of the force is reduced, which can suppress the deformation of the flange.

[0017] The height specified above can also be more than half the thickness of the paper material.

[0018] This ensures the minimum height of the stepped section, preventing it from being sealed during cover sealing.

[0019] When the boundary between the cylindrical body and the flange is taken as the fulcrum of the force when the cover is opened, and the starting point of the stepped portion is taken as the point of application of the force, the specified width can be set to a length in which the torque of the force is less than 60 N·mm.

[0020] Therefore, by ensuring that the torque applied during opening is less than 60 N·mm, deformation of the flange during opening can be suppressed while maintaining the seal strength. When the torque applied is 60 N·mm or more, flange deformation may occur during opening. Furthermore, the width of this stepped portion is approximately twice the thickness of the paper material.

[0021] The flange portion may also have: a two-layer portion located below the stepped portion, where, when viewed in the radial direction of the tube portion, the paper material overlaps by two sheets; and a three-layer portion located further inward than the two-layer portion, where, when viewed in the same cross-section, the paper material overlaps by three sheets. In this case, the two-layer portion may have one adhesive portion for bonding the two sheets of paper, and the three-layer portion may have two adhesive portions for bonding the three sheets of paper.

[0022] Therefore, the strength of the stepped section can be improved in the second layer, and the third layer can stably seal with high strength when the cover material is sealed.

[0023] The aforementioned flange portion may also have a space between the aforementioned adhesive portion of the second layer and the aforementioned adhesive portion of the third layer.

[0024] Therefore, by forming a space between the three-layer part with high sealing strength and the two-layer part with low sealing strength of the cover material, a part with a sealing strength lower than that of the three-layer part 35 and higher than that of the two-layer part 34 is formed. The sealing strength can be improved in stages from the outer peripheral side to the inner peripheral side of the flange. Therefore, when the cover material is opened, the torque of the force can be gradually increased from the outer peripheral side to the inner peripheral side to improve the opening performance.

[0025] Another aspect of the present invention relates to a method for manufacturing a container, comprising:

[0026] The adhesive paper material, coated with thermoplastic resin, is formed into a cylindrical body with side seams on its sides.

[0027] A bottom is formed at one end of the aforementioned cylindrical body.

[0028] The other end of the aforementioned cylindrical body is then rolled to form a rolled flange.

[0029] By pressing the outer peripheral end of the aforementioned flange portion, a stepped portion with a specified height and width is formed.

[0030] Therefore, by simply adding a pressing and molding process to the existing manufacturing process of the coiled part, it is possible to manufacture a container that can suppress deformation of the flange when the lid is sealed and when it is opened.

[0031] Invention Effects

[0032] As explained above, according to the present invention, a container and a method for manufacturing the container can be provided that suppress deformation of the flange portion during sealing and opening of the lid material without changing the sealing conditions of the lid material. However, this effect does not limit the present invention. Attached Figure Description

[0033] Figure 1 This is a diagram showing the front view of a paper cup according to one embodiment of the present invention.

[0034] Figure 2 for Figure 1 An enlarged sectional view of the flange portion.

[0035] Figure 3 A diagram showing the results of the study used to determine the height of the stepped portion of the aforementioned flange.

[0036] Figure 4 A diagram showing the experimental results used to determine the width of the stepped portion of the aforementioned flange.

[0037] Figure 5The figure is shown to compare the experimental results of the deformation of the flange portion during sealing and the change in the outer diameter of the opening with the circularly rolled flange portion in the prior art.

[0038] Figure 6 This is a flowchart illustrating the manufacturing process of the paper cups described above. Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0040] [The appearance of the paper cup]

[0041] Figure 1 This is a diagram showing the front view of a paper cup, which is a container according to one embodiment of the present invention. A portion of the diagram is shown in cross-section.

[0042] As shown in the figure, the paper cup 100 of this embodiment has a cylindrical body 1 and a bottom 2.

[0043] The cylindrical body 1 is constructed by laminating paper (base paper) with a thermoplastic resin such as polyethylene, polypropylene, or polyester, punching it into a fan-shaped blank, winding it around a cylindrical mold, and bonding the side ends together by overlapping them. By bonding the side ends together, a side seam 4 is formed on the side of the cylindrical body 2 from top to bottom.

[0044] The bottom 2 is constructed in such a way that a circular bottom paper, which is punched from the same paper material as the tube body 1, is drawn and bonded to the inner side of the lower end of the tube body 1 while being bonded to the tube body 1.

[0045] The lower end of the tube body 1, to which the bottom 2 is glued, is formed by folding the paper inward and pressing it together. In addition, a flange 3 is formed at the upper end of the tube body 1 to roll the paper outward, and the tube body 1 is in an open state at the flange 3.

[0046] After the paper cup 100 is filled with beverages, ice, or other contents, a lid material such as a polyethylene film is bonded to the flange portion 3 by heat sealing, thereby sealing the paper cup 100.

[0047] The paper used as the raw material for the aforementioned cylinder body 1 and bottom 2 is, for example, composed of multiple layers. In addition to the laminate formed using the aforementioned thermoplastic resin, synthetic resin layers, foamed layers, metal layers, inorganic vapor-deposited films, etc., can also be laminated in this paper.

[0048] In cases where the contents are hard objects such as ice, in order to prevent the paper cup 100 from breaking, the body 1 and the bottom 2 may be further laminated with a resin film such as polyethylene terephthalate.

[0049] [Shape of the flange]

[0050] Figure 2 For the aforementioned flange portion 3 ( Figure 1 An enlarged sectional view of part E.

[0051] As shown in the figure, the flange portion 3 has: a sealing surface 31 for bonding the cover material, a rolled portion 32 formed by rolling up the cylindrical body portion 1, and a stepped portion 33.

[0052] The width A of the flange portion 3 is 2 to 5 mm, and the thickness B of the flange portion 3 is approximately three times the thickness T of the paper material.

[0053] A stepped portion 33 is formed on the outer peripheral end of the upper surface of the flange portion 3. As described later, the stepped portion 33 is formed by pressing the outer peripheral end of the rounded flange portion.

[0054] By providing this stepped portion 33, when the cover is sealed, the sealing head does not contact the stepped portion 33 but only the inner side (sealing surface 31) of the flange portion 3, thereby preventing deformation of the flange portion 3. Furthermore, when the cover is opened, the point of application W of the opening force relative to the fulcrum F (the boundary between the cylinder portion 1 and the flange portion 3) of the opening force (arrow in the figure) becomes more inward than the outer peripheral end of the flange portion 3 (the starting point of the stepped portion 33), thus the torque of the force is reduced, which can suppress deformation of the flange portion 3.

[0055] Furthermore, the flange portion 3 has: a two-layer portion 34 located below the stepped portion 33, which overlaps two sheets of paper when viewed in cross-section in the radial direction (X direction) of the tube body portion 1; and a three-layer portion 35 located further inward than the two-layer portion 34, which overlaps three sheets of paper when viewed in the same cross-section. That is, the stepped portion 33 is formed by retaining the portion of the inner periphery of the circularly curled flange portion that overlaps three sheets of paper as is, and pressing the portion of the outer periphery that overlaps two sheets of paper.

[0056] The second layer 34 has an adhesive portion 34a that bonds the two sheets of paper together by welding or the like, and the third layer 35 has two adhesive portions 35a and 35b that bond the three sheets of paper together by welding or the like. Thus, the strength of the stepped portion 33 can be improved in the second layer 34, and the third layer 35 can provide a stable and high-strength seal when the cover material is sealed.

[0057] Furthermore, a space S is formed between the adhesive portion 34a of the second layer 34 and the adhesive portions 35a and 35b of the third layer 35. Thus, by forming the space S between the third layer 35 (high sealing strength) and the second layer 34 (low sealing strength), a portion with a sealing strength lower than the third layer 35 but higher than the second layer 34 is formed. Therefore, the sealing strength can be progressively increased from the outer periphery to the inner periphery of the flange 33, thereby improving the opening performance by gradually increasing the torque from the outer periphery to the inner periphery when the cover is opened.

[0058] Here, the height D of the stepped portion 33 (the distance between the sealing surface 31 and the bottom surface of the stepped portion 33) is set to more than half of the thickness T of the paper material.

[0059] Figure 3 This table shows the research results used to determine the height D of the stepped section 33. As shown in the figure, the inventors calculated the thickness of the compressed paper during the pressing process for four types of base paper (base paper A to D) with different densities.

[0060] Based on actual usage results, the density of the base paper for Paper Cup 100 is 0.75 g / cm³. 3 The inherent density of cellulose, the main component of the base paper, is 1.5 g / cm³. 3 Therefore, the compression ratio is below 2.

[0061] As described above, when the stepped portion 33 is formed by retaining the portion with three overlapping sheets of paper on the inner periphery of the curled flange (corresponding to the three-layer portion 35) as is, and pressing the portion with two overlapping sheets of paper on the outer periphery (corresponding to the two-layer portion 34), as shown in the figure, the difference between the thickness of the three sheets of paper after compression and the thickness of the two sheets of paper after compression (equivalent to the height of the stepped portion 33) is 0.15 mm (half of the thickness T of the original paper). Therefore, the height D of the stepped portion 33 is preferably set to T / 2 or more.

[0062] Furthermore, when the boundary between the cylinder body 1 and the flange 3 is set as the fulcrum F of the force when the cover is opened, and the starting point of the stepped portion 33 is set as the point of application of the force W, the width C of the stepped portion 33 (the distance from the boundary between the sealing surface 31 and the stepped portion 33 to the outer peripheral end of the flange 3) is set to a length such that the point of application W is located approximately near the center in the width A direction (X direction) of the flange 3.

[0063] Figure 4 This is a table showing the experimental results used to determine the width C of the stepped portion. As shown in the figure, the inventors changed the distance from the fulcrum F to the point of action W (width of flange 3 - width of stepped portion 33) and measured the peel strength and torque of the force when opening the sealed cover material.

[0064] The thickness of the base paper used in the experiment was approximately 0.30 mm, and the width of the flange 3 was set to 3.0 mm. Furthermore, the sealing conditions for the cover were set as follows: sealing time 1.2 sec, sealing temperature 130°C, and sealing pressure 130 kgf.

[0065] As shown in the figure, by setting the distance from the fulcrum F to the point of action W to be less than 3.0 mm and setting the torque of the force when opening to be less than 60 N·mm, a peel strength of 15 N to 20 N can be maintained to keep the opening function. However, when the peel strength is above 20 N (the torque of the force is above 60 N·mm), the flange 3 sometimes deforms (causing it to lift) and cannot be opened.

[0066] Therefore, the width C of the stepped portion 33 is preferably set to a length such that the torque of the force applied to the point of action W when the cover is opened is less than 60 N·mm. This width C is approximately twice the thickness T of the paper.

[0067] Figure 5 The table is presented to compare the experimental results of the deformation of the flange portion 3 constructed as described above during sealing and the change in the outer diameter of the opening with the prior art's coiled flange portion.

[0068] As shown in the figure, for the circularly curled flange portion in the prior art and the flange portion 3 of this embodiment, measurements were taken in the X direction (excluding the outer diameter of the side seam portion 4) and the Z direction (including the outer diameter of the side seam portion 4) before and after the cover material was sealed. Figure 1 Calculate the average, maximum, minimum, range (difference between maximum and minimum) and standard deviation of the outer diameter of the mouth of the ).

[0069] In the existing circularly coiled flange portion, the average value is +0.7mm in the X direction and +0.9mm in the Z direction, indicating a large dimensional variation. In contrast, in the flange portion 3 of this embodiment, the average value is -0.1mm in the X direction and -0.1mm in the Z direction, indicating a very small dimensional variation.

[0070] Therefore, it has been confirmed that the stepped portion 33 of this embodiment can prevent deformation and changes in the external dimensions of the opening during sealing.

[0071] [Paper Cup Manufacturing Method]

[0072] Next, the manufacturing method of the paper cup 100 will be explained. Figure 6 A flowchart illustrating the manufacturing process of paper cup 100.

[0073] As shown in the figure, firstly, paper is obtained by laminating the above-mentioned thermoplastic resin. A fan-shaped blank is punched from the paper and, while its two ends are melted by a gas burner or the like, it is wrapped around a cylindrical mold and bonded to form the cylindrical body 1 (step 61).

[0074] Furthermore, a circular bottom paper, cut from the same paper material as described above, is drawn and, while being vacuum-adsorbed in the cylindrical mold, is bonded to the inner side of the lower end of the cylindrical body 1 while the ends of the cylindrical body 1 are bonded to each other. Then, the lower end of the cylindrical body 1 is folded inward and pressed towards the bottom 2, thereby joining the bottom 2 to the cylindrical body 1 (step 62).

[0075] Next, by rolling, the upper end of the cylinder 1 is rolled outward while being rotated with a tool, thereby forming a flange portion with a circular cross-section in the radial direction (X direction) of the cylinder 1 (step 63).

[0076] Next, regarding the flange portion with a circular cross-section, as described above... Figure 2 As shown, the outer peripheral end is pressed to form a stepped portion 33 (step 64). Thus, a paper cup 100 with an open top is manufactured.

[0077] Then, ice, beverage or other contents are filled into the paper cup 100, and the lid is bonded to the opening (sealing surface 31 of flange 3) by heat sealing, thereby sealing the paper cup 100 (step 65).

[0078] During the heat sealing process, the sealing head first presses the sealing surface 31 and then the stepped portion 33. Therefore, corresponding to the time interval, the sealing strength of the sealing surface 31 becomes higher and the sealing strength of the stepped portion 33 becomes lower.

[0079] [Summarize]

[0080] As explained above, according to this embodiment, by providing a stepped portion 33 at the outer peripheral end of the upper surface of the flange portion 3, deformation of the flange portion 3 during sealing and opening of the cover material can be suppressed. Therefore, without changing the sealing conditions of the cover material, it is possible to prevent changes in the outer diameter of the flange portion 3 during sealing, prevent a deterioration in the fit of the cover (top cover) that engages with the flange portion 3, and enable stable opening during opening.

[0081] [Variation Example]

[0082] This technology is not limited to the above-described implementation methods, and various modifications can be made without departing from the spirit of this technology.

[0083] The shapes of the flange portion 3 and the stepped portion 33 are not limited to those described above. Figure 2 The shape shown. For example, Figure 2The stepped portion 33 shown is composed of a bottom surface that is substantially parallel to the sealing surface 31 and an inclined surface that connects the sealing surface 31 to the bottom surface. However, the inclined surface can be made to be more vertical, and the bottom surface can be made wider.

[0084] In the above-described embodiment, the body 1 and the bottom 2 are manufactured as separate components, and the paper cup 100 is manufactured by bonding the bottom 2 to the body 1. However, the body and bottom can also be integrally formed from a single sheet of paper to manufacture containers such as paper cups, and even in this case, the flange can be formed in the same manner as in the above-described embodiment.

[0085] In the above embodiment, a paper cup 100 is shown as a container, but the container is not limited to a cup and can also be a container for holding food such as snacks.

Claims

1. A container having: The cylindrical body is formed by bonding paper material covered with thermoplastic resin, and has side seams on the sides. A flange portion, formed of rolled-up paper material at one end of the tube body, is heat-sealed and bonded to the cover material; and The bottom, which is formed at the other end of the cylindrical body, The flange portion has a sealing surface for bonding the cover material on its inner side of its upper surface, and a stepped portion at its outer peripheral end of its upper surface. The stepped portion is composed of a bottom surface and an inclined surface, the inclined surface connecting the sealing surface to the bottom surface, and the bottom surface being closer to the bottom than the sealing surface. The height of the stepped portion is the distance between the sealing surface and the bottom surface of the stepped portion, and the height is more than half the thickness of the paper material. The stepped portion also has a specified width.

2. The container according to claim 1, wherein, When the boundary between the cylindrical body and the flange is used as the fulcrum of the force when the cover is opened, and the starting point of the stepped portion is used as the point of application of the force, the specified width is set to be the length of the force with a torque of less than 60 N·mm.

3. The container according to claim 1, wherein, The flange portion has: The second layer, located below the stepped section, has two overlapping sheets of paper when viewed in cross-section along the radial direction of the tube body; and The third layer, located further inward than the second layer, consists of three overlapping sheets of paper in the cross-section. The second layer has an adhesive portion that bonds the two sheets of paper together. The three-layer section has two adhesive portions that bond the three sheets of paper together.

4. The container according to claim 3, wherein, The flange portion has a space between the adhesive portion of the second layer and the adhesive portion of the third layer.

5. A method for manufacturing a container, comprising: Paper materials coated with thermoplastic resin are bonded together to form a cylindrical body with side seams. A bottom is formed at one end of the cylindrical body. The other end of the cylindrical body is rolled to form a rolled flange. A stepped portion is formed by pressing the outer peripheral end of the flange portion. The stepped portion is composed of a bottom surface and an inclined surface. The inclined surface connects the sealing surface on the inner side of the flange portion, which is used for bonding the cover material, to the bottom surface. The bottom surface is closer to the bottom than the sealing surface. The height of the stepped portion is the distance between the sealing surface and the bottom surface of the stepped portion, and the height is more than half the thickness of the paper material. The stepped portion also has a specified width.

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