Container and container manufacturing method

Abstract

This container comprises a cylindrical barrel part, a flange part, and a bottom part. The barrel part has a side seam part formed by bonding a paper material coated with a thermoplastic resin at a side surface thereof. The flange part is formed of a paper material caught in one end of the barrel part, and has a lid material bonded thereto by heat sealing. The bottom part is formed at the other end of the barrel part. The flange pat has a step part having a prescribed height and a prescribed width at an outer peripheral end of an upper surface thereof.

Description

[Technical Field]

[0001] The present invention relates to a container for food and beverages and a method for making the same. [Background technology]

[0002] BACKGROUND ART Conventionally, as a container (paper cup) for food and beverages, a container having a body made of a sheet-like material with a side seam (bonded portion) and a bottom attached to the inside of the body, the open end of which is sealed with a film-like lid material, has been widely used.

[0003] The open end of the container has a flange portion that faces outward from the container, and after the container is filled with contents such as a beverage, a lid material is attached to the flange portion by, for example, heat sealing.

[0004] The following Patent Document 1 describes that the flange portion (mouth roll) is formed so that its cross section is circular (curled).

[0005] Patent Document 2 below describes that the flange portion (cup rim portion) is pressed from above and below to be formed flat. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2008-507458 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-042987 Summary of the Invention [Problem to be solved by the invention]

[0007] However, if the flange portion has a curled shape as described in Patent Document 1, the flange portion may deform when the lid material is sealed, changing the outer diameter of the opening, which may result in poor fit of the lid (overcap) that is fitted to the flange portion.

[0008] Furthermore, if the flange portion has a curled shape as described in Patent Document 1 above, or a pressed flat shape as described in Patent Document 2 above, the flange portion may deform when the lid material is opened, making it impossible to open stably, and as described above, the fitting ability of the lid may become poor.

[0009] In view of the above circumstances, the object of the present invention is to provide a container and a method for manufacturing such a container that can suppress deformation of the flange portion when sealing and opening the lid material without changing the sealing conditions of the lid material. [Means for solving the problem]

[0010] To achieve the above object, one aspect of the present invention provides a container having a cylindrical body, a flange, and a bottom. The body has a side seam formed by bonding a paper material coated with a thermoplastic resin to a side surface. The flange is formed by the paper material wrapped around one end of the body, and a lid material is bonded to it by heat sealing. The bottom is formed at the other end of the body. The flange has a step of a predetermined height and width at the outer peripheral edge of its upper surface.

[0011] With this configuration, a step is provided at the outer peripheral edge of the upper surface of the flange, and when the lid material is sealed, the seal head does not come into contact with the step but only with the inside of the flange, preventing deformation of the flange. Furthermore, when the lid material is opened, the point of action of the opening force relative to the fulcrum (the boundary between the body and flange) is located inside the outer peripheral edge of the flange (the starting point of the step), reducing the moment of force and suppressing deformation of the flange.

[0012] The predetermined height may be equal to or greater than half the thickness of the paper material.

[0013] This ensures that the height of the step portion is at a minimum, and prevents the step portion from being sealed when the lid material is sealed.

[0014] The specified width may be set to a length such that, when the boundary between the body portion and the flange portion is the fulcrum of the force when the lid material is opened and the starting point of the step portion is the point of application of the force, the moment of the force is less than 60 N·mm.

[0015] This allows the force moment when opening to be less than 60 N·mm, which prevents deformation of the flange when opening while maintaining seal strength. If the force moment is 60 N·mm or more, there is a risk of deformation of the flange when opening. The width of such a step is generally more than twice the thickness of the paper material.

[0016] The flange portion may have a two-layer portion located below the step portion and having two overlapping sheets of paper in a cross-sectional view in the radial direction of the body portion, and a three-layer portion located more inward than the two-layer portion and having three overlapping sheets of paper in the cross-sectional view. In this case, the two-layer portion may have one adhesive portion bonding the two sheets of paper together, and the three-layer portion may have two adhesive portions bonding the three sheets of paper together.

[0017] This allows the strength of the stepped portion to be increased in the two-layer portion, and allows the three-layer portion to be sealed with a stable, high strength when the lid material is sealed.

[0018] The flange portion may have a space between the adhesive portion of the second layer portion and the adhesive portion of the third layer portion.

[0019] This creates a space between the three-layer portion of the lid material, which has a high sealing strength, and the two-layer portion, which has a low sealing strength, resulting in a portion with a sealing strength lower than the three-layer portion 35 and higher than the two-layer portion 34.This allows the sealing strength to be increased in stages from the outer periphery to the inner periphery of the flange portion, so that when the lid material is opened, the force moment can be gradually increased from the outer periphery to the inner periphery, improving openability.

[0020] A container manufacturing method according to another aspect of the present invention includes: a paper material coated with a thermoplastic resin is bonded to form a cylindrical body having a side seam on the side; A bottom is formed at one end of the body portion, The other end of the body is rolled to form a curled flange portion. The method includes press-molding the outer peripheral edge of the flange portion to form a step portion having a predetermined height and a predetermined width.

[0021] This makes it possible to manufacture a container that can suppress deformation of the flange portion when the lid material is sealed and opened, simply by adding a press molding process for the outer peripheral edge to the conventional manufacturing process for the curled portion. [Effects of the Invention]

[0022] As described above, according to the present invention, it is possible to provide a container and a method for manufacturing the container that can suppress deformation of the flange portion when sealing and opening the lid without changing the sealing conditions of the lid. However, this effect does not limit the present invention. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram showing the front appearance of a paper cup according to one embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view of a flange portion in FIG. [Figure 3] 10A and 10B are diagrams showing the results of a study to determine the height of the step portion of the flange portion. [Figure 4]10A and 10B are diagrams showing the results of an experiment for determining the width of the step portion of the flange portion. [Figure 5] 10 is a diagram showing experimental results of deformation of the flange portion during sealing and change in the outer diameter of the opening, in comparison with a conventional round curled flange portion. FIG. [Figure 6] 1 is a flowchart showing the manufacturing process of the paper cup. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] [Appearance of paper cup] Fig. 1 is a diagram showing the front appearance of a paper cup as a container according to one embodiment of the present invention, with a portion of the figure shown in cross section.

[0026] As shown in the figure, the paper cup 100 according to this embodiment has a body 1 and a bottom 2.

[0027] The body 1 is made by punching out a fan-shaped blank from a raw paper material (base paper) that has been coated (laminated) with a thermoplastic resin such as polyethylene, polypropylene, or polyester, and then wrapping the blank around a cylindrical mold and gluing the side edges together. This gluing of the side edges together forms a side seam 4 on the top and bottom of the side of the body 2.

[0028] The bottom 2 is made by drawing a circular bottom paper punched out from the same paper material as the body 1, and is adhered to the inside of the lower end of the body 1 at the same time as the body 1 is adhered.

[0029] The bottom end of the body 1, to which the bottom 2 is attached, has paper folded inward and pressed. At the top end of the body 1, a flange 3 is formed with paper folded outward, and the body 1 is open at this flange 3.

[0030] After the paper cup 100 is filled with contents such as beverages or ice, a lid material such as polyethylene film is attached to the flange portion 3 by heat sealing, thereby sealing the paper cup 100.

[0031] The paper material used as the raw material for the body 1 and bottom 2 may be composed of multiple layers, for example. In addition to the thermoplastic resin laminate layer, the paper material may also be laminated with a synthetic resin layer, a foam layer, a metal layer, an inorganic vapor deposition film, or the like.

[0032] To make the paper cup 100 less likely to break when the contents are hard objects such as ice, the body 1 and bottom 2 may be further laminated with a resin film such as polyethylene terephthalate.

[0033] [Flange shape] FIG. 2 is an enlarged cross-sectional view of the flange portion 3 (part E in FIG. 1).

[0034] As shown in the figure, the flange portion 3 has a sealing surface 31 to which the lid material is adhered, a rolled-up portion 32 around which the body portion 1 is rolled up, and a step portion 33.

[0035] The width A of the flange portion 3 is 2 to 5 mm, and the thickness B of the flange portion 3 is approximately equal to three times the thickness T of the paper material.

[0036] The step portion 33 is formed at the outer peripheral edge of the upper surface of the flange portion 3. As will be described later, the step portion 33 is formed by press-molding the outer peripheral edge of the rounded flange portion.

[0037] By providing this step 33, when sealing the lid, the seal head does not come into contact with the step 33 but only with the inside of the flange 3 (seal surface 31), preventing deformation of the flange 3. Furthermore, when opening the lid, the point of application W of the opening force (arrow in the figure) with respect to the fulcrum F (boundary between the body 1 and flange 3) is located inside the outer peripheral edge of the flange 3 (starting point of the step 33), so the moment of force is smaller and deformation of the flange 3 can be suppressed.

[0038] The flange 3 also has a two-layer portion 34 located below the step portion 33 and consisting of two overlapping layers of paper material in a cross-sectional view in the radial direction (X direction) of the body 1, and a three-layer portion 35 located more inward than the two-layer portion 34 and consisting of three overlapping layers of paper material in the cross-sectional view. In other words, the step portion 33 is formed by leaving the innermost three-layer overlapping layer of paper material as it is in the round curled flange, and pressing the outer peripheral edge portion consisting of two overlapping layers of paper material.

[0039] The two-layer portion 34 has one adhesive portion 34a that bonds the two sheets of paper together by fusion or the like, and the three-layer portion 35 has two adhesive portions 35a and 35b that bond the three sheets of paper together by fusion or the like. This increases the strength of the stepped portion 33 in the two-layer portion 34, and allows the three-layer portion 35 to seal stably with high strength when sealing the lid material.

[0040] Furthermore, a space S is formed between the adhesive portion 34a of the second-layer portion 34 and the adhesive portions 35a and 35b of the third-layer portion 35. This forms a space S between the three-layer portion 35, which has a high sealing strength of the lid material, and the second-layer portion 34, which has a low sealing strength, resulting in the formation of a portion with a lower sealing strength than the three-layer portion 35 and a higher sealing strength than the second-layer portion 34. Therefore, the sealing strength can be increased in stages from the outer periphery to the inner periphery of the flange portion 33, and therefore the force moment can be gradually increased from the outer periphery to the inner periphery when the lid material is opened, thereby improving the ease of opening.

[0041] Here, the height D of the step portion 33 (the distance between the sealing surface 31 and the bottom surface of the step portion 33) is set to be equal to or greater than half the thickness T of the paper material.

[0042] Fig. 3 is a table showing the results of a study to determine the height D of the step portion 33. As shown in the figure, the inventors calculated the thickness of four types of base paper (base papers A to D) with different densities after compression during the press molding.

[0043] The base paper of the paper cup 100 has a density of 0.75 g / cm 3 or more based on usage records, and the intrinsic density of cellulose, the main component of the base paper, is 1.5 g / cm 3 , so the compression ratio is 2 or less.

[0044] As described above, step portion 33 is formed by leaving the innermost portion of the curled flange where three layers of base paper overlap (corresponding to three-layer portion 35) as is, and pressing the outermost portion where two layers of base paper overlap (corresponding to two-layer portion 34), and as shown in the figure, the difference between the thickness of three layers of paper after compression and the thickness of two layers of paper after compression (corresponding to the height of step portion 33) is 0.15 mm (half the thickness T of the base paper). Therefore, it is desirable that the height D of step portion 33 be T / 2 or more.

[0045] Furthermore, the width C of the step portion 33 (the distance from the boundary between the sealing surface 31 and the step portion 33 to the outer peripheral edge of the flange portion 3) is set to a length such that, when the boundary between the body portion 1 and the flange portion 3 is taken as the fulcrum F of the force when the lid material is opened and the starting point of the step portion 33 is taken as the point of action W of the force, the point of action W is located approximately near the center of the flange portion 3 in the width A direction (X direction).

[0046] Fig. 4 is a table showing the results of an experiment 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 application W (width of the flange portion 3 - width of the stepped portion 33) and measured the peel strength and moment of force when opening a sealed lid.

[0047] The thickness of the base paper used in the experiment was approximately 0.30 mm, and the width of the flange portion 3 was 3.0 mm. The conditions for sealing the lid material were a sealing time of 1.2 seconds, a sealing temperature of 130°C, and a sealing pressure of 130 kgf.

[0048] As shown in the figure, by keeping the distance from fulcrum F to point of application W less than 3.0 mm and the force moment at the time of opening less than 60 N·mm, it was possible to maintain a peel strength of 15 N to 20 N and retain the opening function; however, when the width was such that the peel strength was 20 N or more (the force moment was 60 N·mm or more), flange portion 3 deformed (lifted up), and in some cases it became impossible to open.

[0049] Therefore, it is preferable that the width C of the step portion 33 is set to a length such that the moment of the force applied to the point of application W when the lid is opened is less than 60 N·mm. The width C is generally greater than twice the thickness T of the paper material.

[0050] FIG. 5 is a table showing the results of an experiment on the deformation and change in the outer diameter of the opening when the flange portion 3 constructed as described above is sealed, in comparison with a conventional round curled flange portion.

[0051] As shown in the figure, the outer diameters of the openings of a conventional round curled flange and the flange 3 of this embodiment were measured in the X direction (outer diameter excluding the side seam portion 4) and the Z direction (outer diameter including the side seam portion 4) (FIG. 1) before and after sealing the lid material, and the average, maximum, minimum, range (the difference between the maximum and minimum values), and standard deviation were calculated.

[0052] In the conventional round curled flange portion, the dimensional change was large, with an average value of +0.7 mm in the X direction and +0.9 mm in the Z direction, whereas in the flange portion 3 of this embodiment, the dimensional change was extremely small, with an average value of -0.1 mm in the X direction and -0.1 mm in the Z direction.

[0053] Therefore, it was demonstrated that the step portion 33 of this embodiment can prevent deformation and change in the outer dimensions of the opening during sealing.

[0054] [Paper cup manufacturing method] Next, a description will be given of a method for manufacturing the paper cup 100. Figure 6 is a flowchart showing the flow of the manufacturing process for the paper cup 100.

[0055] As shown in the figure, first, a fan-shaped blank is punched out from paper material laminated with the thermoplastic resin, and both ends of the blank are melted with a gas burner or the like and then wrapped around a cylindrical mold and glued together to form the body 1 (step 61).

[0056] Furthermore, a circular bottom paper punched from the same paper material as above is drawn and vacuum-adsorbed onto the cylindrical mold, and is simultaneously adhered to the ends of the body 1 and the inside of the lower end of the body 1. The lower end of the body 1 is then folded into the bottom 2 and crimped, thereby joining the bottom 2 to the body 1 (step 62).

[0057] Next, by a curling process, the upper end of the body 1 is curled outward while being rotated by a tool, thereby forming a flange portion whose cross section in the radial direction (X direction) of the body 1 is circular (step 63).

[0058] Next, the outer peripheral edge of the circular cross-section flange is pressed as shown in Figure 2 to form the step portion 33 (step 64). This produces a paper cup 100 that is open at the top.

[0059] Then, the paper cup 100 is filled with ice, beverages, or other contents, and the lid is heat-sealed to adhere to the opening (seal surface 31 of flange portion 3), thereby sealing the paper cup 100 (step 65).

[0060] During this heat sealing, the seal head presses the seal surface 31 first, and then the step portion 33 later, so that due to the time lag, the seal strength at the seal surface 31 is high and the seal strength at the step portion 33 is low.

[0061] [summary] As described above, according to this embodiment, by providing the step portion 33 at the outer peripheral edge of the upper surface of the flange portion 3, it is possible to suppress deformation of the flange portion 3 when sealing and unsealing the lid. This prevents the outer diameter of the opening of the flange portion 3 from changing when sealing, without changing the sealing conditions of the lid, prevents deterioration of the fit of the lid (overcap) that fits onto the flange portion 3, and allows for stable unsealing.

[0062] [Variations] The present technology is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present technology.

[0063] The shapes of the flange portion 3 and the step portion 33 are not limited to those shown in Fig. 2. For example, the step portion 33 shown in Fig. 2 is configured with a bottom surface that is approximately parallel to the sealing surface 31 and a slope connecting the sealing surface 31 and the bottom surface, but the slope may be made closer to a vertical surface and the bottom surface may be formed wider.

[0064] In the above-described embodiment, the body 1 and the bottom 2 are manufactured as separate parts, and the paper cup 100 is manufactured by adhering the bottom 2 to the body 1. However, a container such as a paper cup may also be manufactured by integrally forming the body and the bottom from a single sheet of paper material, and in this case, the flange portion can be formed in the same manner as in the above-described embodiment.

[0065] In the above embodiment, the paper cup 100 is shown as a container, but the use of the container is not limited to a cup, and it may be one that holds food such as sweets, for example.

Claims

1. a cylindrical body portion having a side seam portion formed by bonding a paper material coated with a thermoplastic resin; a flange portion formed by the paper material rolled up at one end of the body portion and having an upper surface to which a lid material is adhered by heat sealing; a bottom portion formed at the other end of the body portion, the flange portion has a step portion of a predetermined height and a predetermined width at the outer peripheral edge of the upper surface, The predetermined width is set to a length such that, when the boundary between the body portion and the flange portion is the fulcrum of the force when the lid is opened and the starting point of the step portion is the point of application of the force, the moment of the force is less than 60 N mm. container.

2. 10. The container of claim 1, The predetermined height is equal to or greater than half the thickness of the paper material. container.

3. 10. The container of claim 1, The flange portion is a two-layer portion located below the step portion and in which two sheets of the paper material are stacked in a cross-sectional view in the radial direction of the body portion; a three-layer portion located more inward than the second-layer portion and in which three sheets of the paper material are stacked in the cross-sectional view; The two-layer portion has one adhesive portion that bonds the two sheets of paper together, The three-layer portion has two adhesive portions that bond the three sheets of paper together. container.

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

5. a paper material coated with a thermoplastic resin is bonded to form a cylindrical body having a side seam on the side; A bottom is formed at one end of the body portion, The other end of the body is rolled to form a curled flange having an upper surface to which a lid material is bonded by heat sealing; a step portion having a predetermined height and a predetermined width is formed by press-molding the outer peripheral edge of the upper surface of the flange portion; The predetermined width is set to a length such that, when the boundary between the body portion and the flange portion is the fulcrum of the force when the lid is opened and the starting point of the step portion is the point of application of the force, the moment of the force is less than 60 N mm. Container manufacturing method.

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