Container and container manufacturing method

Abstract

This container comprises: a cylindrical trunk part formed from a trunk member; a flange section formed by winding one end of the trunk member outwardly; a bottom section formed from the other end of the trunk member and a bottom member; and a seal material having a thermoplastic resin that is bonded to the upper surface of the flange section by heat sealing. The flange section has a first curl section positioned on the outermost circumference of the trunk part in the radial direction, and a second curl section overlapping on the inside of the first curl section. The flange section has, at least at one location in the cross-sectional view in the radial direction, a bonding section for bonding between the first curl section and the second curl section, and has a space having a thickness equal to that of a paper material or greater on the inside of the second curl section.

Description

Container and container manufacturing method

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

[0002] BACKGROUND ART Conventionally, as a container (paper cup) for food and beverages, a container having a body part made of a sheet-like material with a side seam part (bonded part) and a bottom part attached to the inside of the body, the open end of which is sealed with a film-like sealing material (top sealing 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 sealant is attached to the flange portion by, for example, heat sealing.

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

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

[0006] JP-T-2008-507458A JP-A-2004-042987A

[0007] However, if the flange portion has a curled shape as described in Patent Document 1, the flange portion may deform when the sealing material is sealed, causing the outer diameter dimensions of the opening to change, 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 sealing material is opened, making it impossible to open stably, and as described above, the fitting of the lid may become poor.

[0009] Furthermore, if the sealing machine is adjusted to seal plastic cups and the sealing load cannot be adjusted for paper cups, the seal will inevitably be too strong, making it difficult to open.

[0010] 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 (deformation of the outer diameter of the mouth) when sealing and unsealing the sealing material, and that allows the sealing material to be easily unsealed even under strong sealing conditions.

[0011] To achieve the above object, one aspect of the present invention provides a container comprising: a cylindrical body portion formed from a body member; a flange portion formed by folding one end of the body member outward; a bottom portion formed by the other end of the body member and a bottom member; and a sealing material made of a thermoplastic resin adhered by heat sealing to the upper surface of the flange portion. The flange portion has a first curled portion located at the outermost periphery of the body member in the radial direction and a second curled portion overlapping the first curled portion on the inside. The flange portion also has an adhesive portion that bonds the first curled portion and the second curled portion together in at least one location when viewed in cross section in the radial direction, and a space within the second curled portion that is equal to or greater than the thickness of the paper material.

[0012] This configuration, by providing an adhesive portion between the first curled portion and the second curled portion, prevents curling when opening. Furthermore, by providing a space inside the second curled portion, the space acts as a cushion when the sealant is heat-sealed (springback effect). When the space is once compressed by the seal head, a resin pool formed between the flange and the sealant peels off as the space returns to its original shape, forming a notch. This notch serves as a point of action when opening, making it easy to open the sealant even under strong sealing conditions. The thickness of the paper material is, for example, approximately 0.3 mm, but is not limited to this.

[0013] The container may have a resin reservoir between the flange and the sealing material formed by the thermoplastic resin melted during the heat sealing, and a notch between the resin reservoir and the flange formed by the resin reservoir peeling off from the flange due to the springback effect of the space during the heat sealing.

[0014] The flange portion may have a first length in a height direction and a second length in a width direction that is greater than the first length.

[0015] This allows the flange portion to have a more flattened shape than the conventional round curled shape, thereby further suppressing deformation of the flange portion when sealing and unsealing the sealing material, thereby stabilizing the outer diameter of the opening.

[0016] The flange portion may have a step portion of a predetermined height and a predetermined width at the outer peripheral edge of the upper surface thereof.

[0017] This stabilizes the outer shape of the opening, and because the step is not heat-sealed, the point of action when opening can be positioned more inward, and since resin tends to pool in the step during heat sealing, notches are more likely to be formed, further improving openability. Furthermore, because the step makes the space on the outer edge of the flange narrower than the space on the inner edge of the flange, it is possible to achieve both the above-mentioned springback effect and stability of the outer diameter of the opening.

[0018] The adhesive portion may be provided closer to the boundary between the flange portion and the side surface of the body portion than the end portion of the body member that is rolled outward.

[0019] This can better prevent the flange portion from curling when opened, improving the ease of opening.

[0020] A method for manufacturing a container according to another aspect of the present invention includes joining the sides of a body member to form a cylindrical body portion, joining one end of the body member to a bottom member to form a bottom portion, rolling the other end of the body member outward to form a curled flange portion, bonding a first curl portion of the flange portion located at the outermost radial periphery of the body portion to a second curl portion that overlaps the first curl portion on the inside, thereby forming a space inside the second curl portion that is greater than or equal to the thickness of the paper material, and bonding a sealing material to the upper surface of the flange portion by heat sealing.

[0021] As described above, according to the present invention, it is possible to suppress deformation of the flange portion when sealing and unsealing the sealant, and to make it possible to easily unseal the sealant even under strong sealing conditions. However, this effect does not limit the present invention.

[0022] 1 is a diagram showing the front appearance of a paper cup according to one embodiment of the present invention;

[0023] FIG. 1 is an enlarged cross-sectional view of the flange portion in FIG. 1;

[0024] FIG. 2 is a diagram showing experimental results of the openability of the flange portion in comparison with a comparative example;

[0025] FIG. 3 is a diagram showing a relationship curve between the elapsed time (opening position) when opening the flange portion and the opening strength in comparison with a comparative example;

[0026] FIG. 4 is a diagram showing the state of the resin pool on the outer periphery of the flange portion in comparison with a comparative example;

[0027] FIG. 5 is a cross-sectional view showing the change in state of the flange portion when top sealing is performed;

[0028] FIG. 6 is a flowchart showing the manufacturing process of the paper cup.

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0024] [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.

[0025] As shown in the figure, the paper cup 100 according to this embodiment has a body 1 and a bottom 2 .

[0026] The body 1 is made by punching out a fan-shaped blank (body member) from a paper material (base paper) that is 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. The gluing of the side edges together forms a side seam 4 on the top and bottom of the side of the body 1.

[0027] The bottom 2 is made by drawing a circular bottom paper (bottom member) punched out from the same paper material as the body 1, and then adhering it to the inside of the lower end of the body 1 at the same time as the body 1 is adhered.

[0028] The bottom end of the body 1, to which the bottom 2 is attached, has a paper material folded inward and pressed against it. The top end of the body 1 has a flange 3 formed by folding one end of the body material outward, and the body 1 is open at this flange 3.

[0029] After the paper cup 100 is filled with contents such as beverages or ice, a sealing material such as polyethylene film is heat-sealed to the flange portion 3, thereby sealing the paper cup 100.

[0030] The paper material used as the raw material for the body 1 and bottom 2 may be made up 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.

[0031] 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.

[0032] [Shape of Flange Portion] FIG. 2 is an enlarged cross-sectional view of the flange portion 3 (portion E in FIG. 1).

[0033] As shown in the figure, the flange portion 3 has a sealing surface 31 to which the sealing material is adhered, a curled portion 32 around which the body portion 1 is rolled, and a step portion 33 .

[0034] The width A (length in the X direction) of the flange portion 3 is greater than the height B (thickness: length in the Y direction) of the flange portion 3. In other words, unlike the conventional round curl shape, the flange portion 3 of this embodiment has a shape that is flattened in the height direction (Y direction).

[0035] The width A of the flange portion 3 is, for example, 2 to 5 mm, and the thickness B of the flange portion 3 is about 1 to 1.5 mm, which is four times or more the thickness T of the paper material (for example, 0.3 mm).

[0036] The flange portion 3 also has a first curled portion 34 located at the outermost periphery in the radial direction (X direction) of the body portion 1, and a second curled portion 35 that overlaps the first curled portion 34 on the inside. The flange portion 3 also has an adhesive portion 36 that bonds the first curled portion 34 and the second curled portion 35 together, at only one location in a cross-sectional view in the radial direction. That is, the curled portion 32 of the flange portion 3 is bonded by only this one adhesive portion 36.

[0037] The adhesive portion 36 prevents the curl of the flange portion 3 from turning up when the seal material is opened. The adhesive portion 36 is preferably provided closer to the boundary between the flange portion 3 and the side surface of the body portion 1 (on the left side in FIG. 2 ) than to the rolled-up end of the paper material. This further enhances the curl-up prevention effect.

[0038] A space S is formed inside the second curled portion 35 of the flange portion 3. The space S is formed as a result of bonding the curled portion 32 only with the adhesive portion 36 (the second curled portion 35 is not bonded to the underlying layer). The space S is secured in the Y direction to be equal to or larger than the thickness T of the paper material (in the example shown in the figure, approximately twice the thickness T).

[0039] 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.

[0040] By providing the step portion 33, when the seal material is sealed, the seal head does not come into contact with the step portion 33 but only comes into contact with the inside of the flange portion 3 (seal surface 31) (or if it does come into contact, it is only weak contact), thereby preventing deformation of the flange portion 3. Furthermore, when the seal material is opened, the point of action of the fulcrum of the opening force (the boundary between the body portion 1 and the flange portion 3) is located inside the outer peripheral edge of the flange portion 3 (the starting point of the step portion 33), so the moment of force is smaller, which is effective in making the seal easier to open (easy peel). Furthermore, when providing the step portion 33, deformation of the flange portion 3 can be suppressed by performing a press process on the curl (by crushing it once before sealing).

[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 approximately equal to the thickness T of the paper material, but is not limited to this and may be approximately half the thickness T.

[0042] 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, for example, about one-quarter to one-third of the width A of the flange portion 3. When the sealing conditions are appropriate (the area around the step portion 33 is not strongly sealed), a larger width C reduces the moment required to open the package, improving ease of opening.

[0043] 3 is a diagram showing the results of an experiment on the openability of the sealing material of the flange portion 3 in comparison with a comparative example. In the comparative example, the layers of the flange portion are bonded at multiple locations to prevent the formation of the space S.

[0044] The sealing material was sealed under the following conditions: temperature: 165°C, load: 130 kg / cup, and pressure: 2 times. The sealing load for paper cups is generally about 60 kg / cup, so the above conditions can be said to be strong sealing conditions (this sealing load is equivalent to the sealing load for a resin (PET) cup).

[0045] As shown in the figure, in a total of five opening experiments, the flange portion of the comparative example could not be opened even once, whereas the flange portion 3 of this embodiment was successfully opened all five times with a stable opening strength of maximum 26 N, minimum 22 N, and average 24 N.

[0046] In this way, with the flange portion 3 according to this embodiment, the seal material can be stably opened even under strong sealing conditions.

[0047] 4 is a graph showing a curve illustrating the relationship between the elapsed time (opening position) when opening the flange portion 3 and the opening strength, in comparison with the comparative example. Note that the flange portion according to the comparative example could not be opened under the strong sealing conditions as shown in FIG. 3, and therefore the opening strength could not be measured. Therefore, in the experiment shown in FIG. 4, the flange portion was sealed under the proper sealing conditions, not the strong sealing conditions.

[0048] As shown in the figure, in the flange portion of the comparative example, a peak of 14 N occurs at the boundary between the body portion and the flange portion, which is the fulcrum of the force for opening the seal material, and a strong peak of 16 N occurs at the outer peripheral edge of the flange portion, which is the point of application of the opening force. It is believed that the high opening strength at the outer peripheral edge, which is the point of application of the opening force, leads to the above-mentioned opening failure under strong seal conditions.

[0049] In contrast, in the flange portion 3 of this embodiment, although a somewhat strong peak of 13 N occurs at the boundary between the body portion 1, which serves as the fulcrum, and the flange portion 3, the opening strength at the action point on the outer periphery (step portion 33) is 10 N, and it can be seen that no strong peak that could lead to opening failure occurs on the outer periphery.

[0050] Here, the reason why the flange portion 3 of this embodiment has high openability even under the strong sealing conditions as described above (particularly, the open strength does not increase on the outer periphery) will be considered.

[0051] FIG. 5 is a diagram showing the state of the resin pool on the outer periphery of the flange portion 3 in comparison with the comparative example.

[0052] As shown in the figure, in the flange portion according to the comparative example, it can be seen that a resin pool formed during heat sealing has adhered to the boundary with the sealing material.

[0053] On the other hand, in the flange portion 3 according to this embodiment, it can be seen that the resin pool at the boundary with the sealing material has peeled off, forming a notch between the sealing material (resin pool) and the flange portion 3.

[0054] Figure 6 is a cross-sectional view showing the state change of the flange portion 3 during top sealing. Figure 6(A) shows the unsealed state, followed by Figures 6(B) to 6(D), and finally Figure 6(E) shows the state after top sealing is completed. The lower part of Figure 6 is an enlarged view of Figures 6(D) and 6(E).

[0055] When the contents are filled into the paper cup 100, the flange portion 3 is set in the sealing bucket S1 from the unsealed state shown in Figure 1(A) to the state shown in Figure 1(B), and the sealing material 40 is set on the sealing surface 31 of the flange portion 3.

[0056] Next, as shown in FIG. 1C, the seal head S2 comes into contact with the seal material 40 from above, presses it while heating it as shown in FIG. 1D, and then rises as shown in FIG. 1E, welding the seal material 40 to the flange portion 3 and completing the heat seal.

[0057] At this time, when the flange portion 3 is compressed as shown in the same figure (D), the space S collapses as shown by the arrow in the same figure, and the molten resin from the sealing material 40 and the surface of the flange portion 3 flows to both ends of the flange portion 3 in the X direction, forming a resin reservoir portion P.

[0058] Then, when the seal head S2 rises as shown in Figure 1(E), the cushioning effect (springback effect) of the space S causes the height of the flange portion 3 to return to its original state, as shown by the arrow in the figure, and the resin reservoir portion P is peeled off from the flange portion 3, forming a notch (cutout) N.

[0059] In other words, the paper cup 100 sealed with the sealing material 40 in this embodiment has a resin reservoir portion P between the flange portion and the sealing material 40, formed by the thermoplastic resin that melts during heat sealing, and a notch N between the resin reservoir portion P and the flange portion 3, formed when the resin reservoir portion P peels off from the flange portion 3 due to the springback effect of the space S during heat sealing.

[0060] The notch N thus formed serves as a point of application of the opening force when the sealing material 40 is opened, making it possible to easily open the sealing material 40 even under strong sealing conditions.

[0061] [Manufacturing Method of Paper Cup] Next, a description will be given of a manufacturing method of the paper cup 100. Fig. 7 is a flowchart showing the flow of the manufacturing process of the paper cup 100.

[0062] As shown in the figure, first, a fan-shaped blank is punched out from the 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).

[0063] A circular bottom paper sheet 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 to the inside of the lower end of the body 1. The lower end of the body 1 is then folded toward the bottom 2 and crimped, thereby joining the bottom 2 to the body 1 (step 62).

[0064] Next, a curling process is performed in which the upper end of the body 1 is rotated by a tool and curled outward, thereby forming a flange portion (round curl) having a circular cross section in the radial direction (X direction) of the body 1 (step 63).

[0065] At this time, before the body portion 1 is rolled up, the vicinity of its upper end is melted in the circumferential direction using hot air, a gas burner, ultrasonic waves, or the like, and then rolled up, thereby bonding the first curled portion 34 and the second curled portion 35 together and forming the adhesive portion 36. As described above, the closer the portion is to the boundary between the flange portion 3 and the side surface of the body portion 1, the more effectively the flange portion 3 is prevented from curling up when the package is opened. Furthermore, by forming the adhesive portion 36 between the first curled portion 34 and the second curled portion 35, a space S is also formed inside the second curled portion 35.

[0066] Next, the circular cross-sectional flange is pressed using a mold with a convex portion formed on its outer periphery to form a step 33 and a flange 3 that is flattened in the height direction (horizontally elongated in cross section) (step 64). This produces a paper cup 100 with an open top. By making the flange 3 horizontally elongated in cross section, it is possible to prevent the outer diameter of the opening of the flange 3 from changing when sealing and opening the cup, and by forming the step 33 in the flange 3, it is possible to stabilize the outer diameter of the opening and improve ease of opening at the same time.

[0067] Then, the paper cup 100 is filled with ice, beverages, or other contents, and the sealing material 40 is heat-sealed to adhere to the opening (sealing surface 31 of the flange portion 3) as shown in Figure 6, thereby sealing the paper cup 100 (step 65).

[0068] During this heat sealing, a notch N is formed from the resin pool P in the step portion 33 due to the cushioning effect (spring back effect) of the space S in the flange portion 3. This improves the ease of opening.

[0069] [Summary] As described above, according to this embodiment, by bonding the flange portion 3 at only one location, it is possible to suppress deformation of the flange portion 3 when sealing and unsealing the sealant 40. Furthermore, by bonding at only one location, a space S is created inside the second curled portion 35, and when the sealant 40 is heat-sealed, a resin pool P between the flange portion 3 and the sealant 40 forms a notch N, and when the sealant 40 is unsealed, the notch N becomes the point of action, making it possible to easily unseal the sealant 40 even under strong sealing conditions (when such conditions are unavoidable).

[0070] Furthermore, since the step portion 33 is not heat-sealed, the point of action when opening can be positioned more inward, and since resin flows into the step portion 33 during heat sealing and a resin pool P is easily formed, a notch N is easily formed, and the ease of opening can be further improved.

[0071] [Modifications] The present technology is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present technology.

[0072] In the above-described embodiment, the adhesive portion 36 of the flange portion 3 is provided in only one location between the first curled portion 34 and the second curled portion 35 in the radial direction (X direction) of the body portion 1. However, the adhesive portion 36 may be provided in multiple locations between the first curled portion 34 and the second curled portion 35. However, if many adhesive portions 36 are provided and the curled portion 32 is firmly fixed, the springback effect due to the space S cannot be obtained, and therefore, from this viewpoint, it is preferable to provide the adhesive portion 36 in only one location.

[0073] In the above-described embodiment, the adhesive portion 36 of the flange portion 3 is formed when the round curl is rolled up, but the adhesive portion 36 may also be formed by pressing with an ultrasonic horn or the like during the press processing for forming the step portion 33 after the round curl is rolled up.

[0074] 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.

[0075] 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.

[0076] In the above-described embodiment, the paper cup 100 is formed by molding the body 1 having the side seam 4 and the bottom 2 from paper material that has been coated in advance with a thermoplastic resin and then connecting the two. However, the paper cup 100 may be formed as a composite paper container by molding the body and bottom from paper material that is not coated with a thermoplastic resin, joining the body (side seam) and the bottom with a resin (adhesive) to form a paper container, and then attaching a resin film to the inner surface of the paper container by vacuum and / or pressure molding.

[0077] In the above embodiment, a paper cup 100 is shown as a container, but the use of the container is not limited to a cup, and it may be something that holds food such as sweets, for example.

[0078] REFERENCE SIGNS LIST 1...Body portion 2...Bottom portion 3...Flange portion 4...Side seam portion 31...Seal surface 32...Curled portion 33...Step portion 34...First curled portion 35...Second curled portion 36...Adhesive portion 40...Sealing material 100...Paper cup S...Space S1...Seal bucket S2...Seal head P...Resin reservoir N...Notch

Claims

1. a cylindrical body portion formed from a body member; a flange portion formed by folding one end of the body member outward; a bottom portion formed by the other end of the body member and a bottom member; a sealing material having a thermoplastic resin adhered to the upper surface of the flange portion by heat sealing, The flange portion is a first curled portion located at the outermost periphery of the body in the radial direction, and a second curled portion overlapping the first curled portion on the inside, a bonding portion that bonds the first curled portion and the second curled portion together is provided at at least one location in a cross-sectional view in the radial direction; The second curled portion has a space therein that is equal to or greater than the thickness of the body member. container.

2. 10. The container of claim 1, a resin reservoir portion formed by the thermoplastic resin melted during the heat sealing is provided between the flange portion and the sealing material, A notch is provided between the resin reservoir and the flange, the notch being formed by the resin reservoir peeling off from the flange due to the springback effect of the space during the heat sealing. container.

3. 3. The container according to claim 1 or 2, The flange portion has a first length in a height direction and a second length in a width direction that is greater than the first length. container.

4. 4. The container of claim 3, The flange portion has a step portion of a predetermined height and a predetermined width at the outer peripheral edge of the upper surface thereof. container.

5. 3. The container according to claim 1 or 2, The adhesive portion is provided closer to the boundary between the flange portion and the side surface of the body portion than the end portion of the body member that is rolled outward. container.

6. The sides of the body member are joined to form a cylindrical body portion; one end of the body member and a bottom member are joined to form a bottom portion; The other end of the body member is rolled outward to form a curled flange portion; a first curled portion of the flange portion located at the outermost periphery in the radial direction of the body portion and a second curled portion that overlaps the first curled portion on the inside thereof, thereby forming a space that is equal to or larger than the thickness of the body member inside the second curled portion; A sealant is attached to the upper surface of the flange portion by heat sealing. Container manufacturing method.