JP2010042869A - Molded container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a molded container of which the curling molding can be carried out good and easily and has excellent shape-retainability, even if it is a paper-made container of which the end of a body opening is highly densified. <P>SOLUTION: The body having a curling section 5 in the end of the body opening and the curling configuration of the above curling section in the molded container of which the bottom has been molded integrally are used to form a folded edge section 6 by folding to the underside from the folded base end of the inside of the predetermined width from the extended flange formed by widening outside from the end of the body opening and this folded edge section is made by forming by involving so as to locate within the curling section 5 and the tip of this folded edge section 6 is located outwardly in the body section within the above curling section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a molded container, particularly a drawn container such as a paper cup manufactured by drawing or drawing and ironing.

  For paper containers such as paper cups and trays, increase strength, prevent infiltration of foreign matter from the end face, take measures against cut paper dust, and in the case of containers that eat and drink directly from the open end of the trunk, such as paper cups, Therefore, it is necessary to curl the body opening end of the container. Curl molding of a barrel opening end in a two-piece paper cup having a trunk seam is performed by pressing the barrel opening end against a curl mold having an annular molding groove. Can be naturally wound along the forming groove, and the curled portion can be formed relatively easily. In this case, the curling mold is preheated to a temperature higher than the softening temperature of the adhesive, and is performed in one step (for example, see Patent Document 1). Alternatively, when the paper cup is a laminated paper provided with a polyethylene layer, heat is applied to the joint portion between the curl tip and the cup portion wound in a curl shape after curling (see Patent Document 2). ) Etc. have been proposed in the past. In some cases, the mold is curled by rotating the pressing die. In this way, in the case of a two-piece container, the shape of the curled portion is maintained without loosening by simply wrapping inwardly, or by adhering when the wrapping is shallow, so that shape retention is maintained. Are better.

  However, in the case of a one-piece container without a seam, the opening end of the trunk is different from the case of a normal two-piece paper cup because of the molding by drawing or drawing and ironing. Therefore, it is difficult to entrain, and even if entrained, it may return with a spring back, and it is difficult to maintain a good curl state due to lack of shape retention. Therefore, in the case of a conventional drawn paper container, only the flange is formed on the end face of the body opening, or the edge of the flange is bent downward, and the edge is not curled. Most of them (for example, see Patent Documents 3 and 4). On the other hand, among the drawn containers, as a curl forming method for a tray-shaped square paper container, the container is drawn so that a flat part having a width capable of forming a flange part and a curled part is formed on the outer peripheral part. A curling member with a curling groove formed with a curling groove formed at the end of the bent portion is bent downward, leaving a portion to become a flange portion, and a curling having a smaller diameter than the curling groove that moves up and down facing the curling member. A method and apparatus for curling in a curled groove by an outer frame member in which the groove is formed has been proposed (see Patent Document 5).

JP 2002-96408 A Japanese Utility Model Publication No. 2-135431 JP 2002-179044 A JP 2003-155018 A JP 2003-160121 A

  In the case of a square drawn container, since there is no wrinkle in the straight part except for the corner part at the opening part of the body part and the hardening of the straight part is relatively small, the curling process is relatively easy. (Curved part), because it becomes a shrinking flange, wrinkles occur, and it is difficult to curl in harmony with the flat part and lacks shape retention. Therefore, in Patent Document 5, the winding diameter of the curved edge winding part is made small. However, it still does not solve the above problem satisfactorily. Of the drawn containers, especially cylindrical containers, many wrinkles are generated around the entire circumference of the open end, and the density and hardness of the container are difficult to curl and lack shape retention. Curling of the barrel opening end in the draw-formed container has not been put into practical use yet. In particular, when the paper container is formed by the drawing ironing method proposed by the present inventors as a new drawing method for a paper container, the body opening end is different from the conventional case of forming a ruled line on the pleat part in advance. A large number of small wrinkles are generated in the part, and the end part of the body part opening is densified, so that curling is difficult. As described above, the molding of the curled portion of the paper drawing container is a major technical problem to be overcome in the manufacture of the paper drawing container, and hinders its practical application.

  Accordingly, the present invention solves the above-described problems of curling of a draw-formed container, and is a molded container in which the body opening end is highly densified by drawing and ironing, including ordinary drawing. However, regardless of whether it is a square container or a round container, the curl can be easily and satisfactorily formed, and a curled part having excellent shape retention can be formed, and the paper drawn container can be put to practical use. An object of the present invention is to provide a drawn container that can be used.

  The molded container of the present invention that solves the above-mentioned problems is a molded container formed by drawing or drawing and squeezing and squeezing a sheet mainly composed of a paper having a barrel part and a bottom part integrally formed at the opening end of the trunk part. The curled shape of the curled portion is bent downward from the bent base end on the inner side of the predetermined width from the end of the extending flange formed to extend outward from the trunk opening end, and forms a bent edge, The bent edge portion is formed so as to be positioned inside the curled portion, and the tip of the bent edge portion is positioned facing the outer side of the body portion in the curled portion. The molding container can be suitably applied to drawing a plate material mainly composed of paper, or drawing and ironing to form a cup-shaped or tray-shaped container.

  According to the molded container of the present invention, the curled portion has a bent edge portion by precurl, and the bent edge portion is wound inside, so that a seamless molded container is formed with a seam by conventional paper molding. A good curling state having the same shape retention as that of the container can be obtained, and the drawn paper container can be put into practical use as a container for beverages and the like. The molded container of the present invention can be applied not only to ordinary drawing molding but also to a drawn ironing molding container, and an unprecedented beautiful molding container with fine wrinkles can be obtained. Further, the molded container of the present invention is bent from the end of the extending flange formed to expand outward from the bent base end of the predetermined width inside to form the bent edge, and in that state the bent edge Since it is wound inside, it has extremely excellent shape retention, and the spring back amount is remarkably reduced as compared with the conventional case where the curled portion is formed simply by winding and a good curled shape is obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an embodiment of a molded container according to the present invention, and in this embodiment, the case is applied to a cup-shaped molded container 1 that has been drawn and ironed. As will be described later, the cup-shaped molded container 1 has a paper material as a main component, and both surfaces thereof are waterproofed or heat-insulated by appropriate means such as laminating a synthetic resin film or impregnating with a synthetic resin. It is formed into a cup shape consisting of a bottom wall 2 and a substantially cylindrical barrel wall 3 from a single sheet by drawing ironing as previously provided by a person, and then the curled portion is formed by curling the barrel opening end. 5 is formed. As shown in FIG. 1, the curled portion 5 has a bent edge portion 6 formed by bending an end portion of the trunk portion, and the curled portion 5 is wound so that the bent edge portion is positioned in the curled portion. Is formed. As the sheet material for container molding, for example, a paper base material laminated with a low-density polyethylene film, a polypropylene film laminated material, or a polyethylene terephthalate film laminated material can be suitably used, but not limited thereto. In addition, an appropriate material can be adopted.

  The curled portion 5 is molded through a process as shown in FIG. As shown in the figure, an extension flange 8 is formed by extending outward from the trunk opening end so as to have a predetermined width, and is bent downward with a predetermined width a from the extension flange portion. An annular bent edge 6 is formed, and is wound so that the annular edge is on the inside, and a curled part 5 having a curled part height c and a curled part width d is formed. In addition, b represents the dimension of the curl part formation area from the trunk | drum opening end. Since the bent edge portion 6 is formed by bending the extending flange 8 along a lower die having a sharp tip at a distal end by a method described later, the bent base end 9 is lowered downward along an annular folding curve. It is in a state of being strongly bent by the cooperative action of the outer punch and the bent edge portion 6 is wound inwardly in that state, so it has extremely excellent shape retention and is simply rolled Compared with the case where the curled portion is formed, the springback amount is remarkably reduced, and a good curled shape can be obtained. Further, even if the trunk opening end is densified in the squeezing and ironing container, it can be easily molded. As a result, the rigidity in the radial direction has been improved, and the seamless cup-shaped container made of seamless paper that can be put to practical use for beverages has been solved. Succeeded in getting.

  3 and 4 show another embodiment of the molded container according to the present invention, and this embodiment shows a case where it is applied to a tray-like square container. Portions similar to those in the above embodiment are given the same reference numerals, and detailed description thereof is omitted. As shown in the plan view of FIG. 4, the tray-shaped rectangular squeezed container 60 of the present embodiment includes a tapered body wall 63 and a bottom wall 64 each having four arcuate corner portions 61 and straight portions 62. The protrusion 65 is attached to the periphery of the bottom wall to form a leg portion, and the panel strength of the bottom wall 64 is increased. In the present embodiment, a plurality of reinforcing ribs 66 are formed on the bottom wall 64 at appropriate intervals. A curled portion 67 is formed at the end of the body opening. The cross-sectional shape of the curled portion 67 has a bent edge portion 6 formed by bending an edge portion, and is formed by being wound so that the bent edge portion 6 is positioned in the curled portion, as in the above embodiment. Yes. The curled portion 67 is formed in the same manner at the corner portion and the straight portion. And the square draw-molded container of this embodiment is also formed by the draw ironing method, and in the case of the conventional draw molding method, many pleats must be formed at the corner portion, but because it is a draw ironing method. Further, it is not necessary to put a crease forming ruled line in advance as in the prior art, and drawing can be performed, and curling can be satisfactorily performed only by generating wrinkles that are extremely smaller than in the prior art. In the case of drawing a rectangular container, it is difficult to form a curled portion all around the circumference as in the case of a cylindrical cup-shaped container. In this embodiment, the finish curl forming process is performed as described later. Curling is performed sequentially by curling rolls that move relatively along the outer peripheral surface.

5 to 8 show a curl forming apparatus for a forming container according to an embodiment of the present invention. In the following description of the embodiment, for convenience of explanation, the vertical type is described based on the display on the paper surface. However, in an actual apparatus, the directionality is not limited and may be a horizontal type.
The curling device of this embodiment is a device for curling the cup-shaped molded container 1 shown in FIG. 1, and precurl molding for bending the open edge of the container by a predetermined width to form a bent edge. It comprises a combination of a device and a finish curl forming device that winds and curls a precurled barrel opening end inward. An outline of the precurl molding apparatus 10 is shown in FIG. 5, a container holder 12 in which a cup is fitted inside is fixed to a die holder 11, and a lower die 13 is fixed to the upper surface of the container holder 12. The lower die 13 may be formed integrally with the same member as the container holder 12 or may be formed integrally with another member.

  On the other hand, the punch holder 15 which moves relative to the die holder is fitted to the inner peripheral surface of the container fitted to the container holder, and the body wall 3 is sandwiched between the container holders during curl molding. An inner punch 16 for preventing the barrel wall from buckling, an outer punch 17 for bending the barrel opening end of the container, and an upper die 18 for holding the barrel wall in cooperation with the lower die when folded are provided. It has been. The outer punch 17 is integrally fixed to the punch holder 15 and is integrally displaced by an appropriate drive mechanism such as a pneumatic cylinder or a motor. The inner punch 16 and the upper die 18 are respectively attached to the punch holder 15 via a spring 19 and a spring 20. It is attached. When the punch holder is raised, the inner punch and upper die 18 protrude downward from the outer punch 17 by the spring, and the inner punch and upper die 18 act first during precurl molding, and then the punch holder 15 further moves. When the outer punch is lowered and acts, the spring is cushioned to maintain the state.

  As shown in an enlarged view of the main part of the precurl molding apparatus having the above-described configuration in FIG. 7, the lower die 13 and the upper die 18 cooperate to open the barrel wall outward from a position a predetermined distance from the barrel opening end. The lower die 13 has a convex molding surface 21 curved outward at the top, and the upper die 18 has a concave molding surface 22 having substantially the same arc as the convex molding surface 21. Accordingly, the portion that has become a flange contracted by drawing is expanded on the contrary to form an elongated flange. By the lower die 13 and the upper die 18, the outer peripheral edge portion of the convex molding surface 21 is bent at an acute angle as shown in FIG. 7, and is connected to the outer peripheral surface of the lower die. When the portion 6 is formed, the leading edge 27 extends into the flange surface so that a linear crease can be formed. The outer peripheral surface of the lower die 13 and the upper die 18 is a cylindrical surface. The lower die 13 and the upper die 18 are sandwiched from above and below and the opening end of the body wall is opened outward while horizontally extending to form the extending flange 8. The thickness of the molding part of the lower die and the upper die is defined so that the portion forming the bent edge of the container protrudes from the cylindrical surface 24.

  On the other hand, the finish curl forming apparatus 30 is schematically shown in FIG. 6, and a container holder 32 in which a cup is fitted inside is fixed to a die holder 31, and a curling die 33 is fixed to the upper surface of the container holder 32. Yes. The curling die 33 may be integrally formed of the same member as the container holder 32, or may be formed of a separate member and integrated. On the other hand, the punch holder 35 that moves relative to the die holder 31 is fitted to the inner peripheral surface of the container fitted to the container holder, and the body wall is sandwiched between the container holders during curl molding. An inner punch 36 for preventing the body wall from buckling, and a molding die 37 for finishing and curling the body opening end of the precurled container are provided. The molding die 37 is integrally fixed to the punch holder 35, and is integrally displaced by an appropriate driving mechanism, and the inner punches 36 are attached to the punch holder 35 via springs 39, respectively, and a predetermined amount with respect to the punch holder 35. Cushioning is possible. Thereby, the container breakage at the time of finish curl molding is prevented.

  As shown in an enlarged view in FIG. 8, the curling die 33 has an arc-shaped curl forming surface 41 so as to wind a bent edge portion formed in the precurling step. An arc-shaped molding surface 42 having a diameter larger than that of the curl molding surface 41 is provided, and when the two are relatively close to each other, the pre-curled trunk opening end portion is gradually wound and finished and curled. In this embodiment, the resistance heater 43 is provided on the outer peripheral surface of the molding die 37 so that the molding die 37 can be heated by a heater. However, the heater may be incorporated in the molding die 37.

Next, a curl forming method of the cup-shaped forming container by the above apparatus will be described with reference to the process diagram of FIG.
As shown in FIG. 2A, the cup that has been drawn or squeezed and ironed in the previous step has a trunk opening end that extends linearly from the trunk wall, and in this state, the precurl molding apparatus 10 Fit into the container holder 12. In the case of a cup-shaped container formed by squeezing and ironing, first, a bottomed cup having a cylindrical body wall is obtained by squeezing and ironing, and then fitted to the container holder 12 shown in FIG. In this state, the inner punch whose outer peripheral surface is tapered in that state descends, so that the body wall of the cup is gradually expanded along the taper surface and the inner punch is completely lowered. As shown in FIG. 5, a tapered drawn container in which the body wall is in close contact with the tapered inner peripheral surface of the container holder 12 is obtained. By processing like this, the area near the end of the body opening is reduced by shrinkage molding due to drawing and ironing, but conversely, it is expanded by tapering, reducing the density and curling. It is easy to do.

  As described above, when the punch holder 15 is lowered, the inner punch 16 is lowered and the body wall 3 of the container is sandwiched and fixed. This prevents buckling of the body wall during molding. Further, when the punch holder 15 is lowered against the spring 19, the annular tapered introduction portion 25 located inside the concave molding surface 22 of the upper die 18 enters the container through the opening of the container, and the tapered surface thereof is the trunk portion. By gradually descending while being pressed against the inner peripheral surface of the wall, the opening end of the body wall gradually opens to the outside, and the body opening end edge 7 bends in a round shape along the concave molding surface 22 to the outside of the upper die. Extend to. Then, in a state where the upper die 18 reaches the lowermost position and is pressed with the upper die and the lower die 13 completely sandwiching the body wall, as shown in FIG. 2 (b), a predetermined width a is formed from the cylindrical outer peripheral surface 24 of the lower die. A protruding elongated flange 8 is formed. Further, when the punch holder 15 is lowered and the outer punch 17 is lowered, the lower surface of the outer punch 17 is bent against the extending flange 8 projecting outward from the cylindrical outer peripheral surface 24 of the lower die 13, and finally the outer punch 17 is bent. As shown in FIG. 7, the outer peripheral surface 26 of the upper die 13 and the outer peripheral surface 26 of the upper die 13 are sandwiched, and the extension flange is bent downward from the protruding base end 9 from the lower die. As a result, the container opening has the shape shown in FIG. 2C. In this state, a strong crease is formed at the protruding proximal end 9, so that the container opening is formed and the spring back is small. As described above, the bent edge 6 is formed, and the precurling process is completed. The container for which the precurl process has been completed is taken out from the precurl molding apparatus and supplied to the next finishing curl molding apparatus.

  In the finishing curl forming process, the container in which the pre-curl has been finished is fitted into the container holder 31 of the finishing curl forming apparatus 30, and then the punch holder 35 is lowered so that the inner punch 36 is lowered to sandwich the body wall 3 of the container. Fix it. This prevents buckling of the body wall during molding. In this state, when the forming die 37 gradually descends, the arc-shaped forming surface 42 has the bent-edge base end 9 of the body wall gradually changed from the large-arc surface of the arc-shaped forming surface 42 to the small-arc surface. By being moved while abutting, it is wound in an arc shape, and by further moving while abutting against the curling molding surface 42 of the curling die 33, it is spirally shaped so that the bent edge portion 6 is completely located inside the curl portion. It is caught in the finish curl. In the finish curling process, the upper die 18 and, if necessary, the curling die 33 are heated to a predetermined temperature, so that the stretch flange of the container can be molded while being heated, and the moldability is improved. The curled portion formed as described above can obtain a good curled state and has a bent edge portion 6 having an acute fold, so that the curled portion does not return and has excellent shape retention. It has sex.

  Next, another curl forming apparatus suitable for curling a square shaped container as shown in FIG. 2 will be described with reference to FIGS. In this curl molding apparatus, the same components as those of the curl molding apparatus are denoted by the same reference numerals, and detailed description thereof is omitted. This curl forming apparatus is composed of a combination of a first precurl forming apparatus 70, a second precurl forming apparatus 71, and a finish curl forming apparatus 72.

  In the first precurl molding apparatus 70, a container holder 75 into which a rectangular container is fitted inside is fixed to a die holder, and a lower die 76 is fixed to the upper surface of the container holder 75, as in the above embodiment. The lower die 76 may be integrally formed with the same member as the container holder 75, or may be formed integrally with another member. An unillustrated punch holder includes an inner punch 76 that is fitted to the inner peripheral surface of the container fitted to the container holder and sandwiches the body wall between the container holder and prevents the body wall from buckling during curl molding. An upper die 77 is fixed. In this embodiment, the inner punch and the upper die are integrally formed as shown in the figure to reduce the number of parts. However, as in the above embodiment, the inner punch and the upper die are formed as separate members, and are connected to the punch holder via a spring. And may be provided so that a predetermined amount can be cushioned. The punch holder is provided with an outer punch 78. The first precurl molding apparatus 70 operates in the same manner as the precurl molding apparatus of the above-described embodiment, forms an extension flange 68 as shown in FIGS. 9 to 10, and then the outer punch 78 descends. As shown in FIG. 11, the bent flange portion 69 is formed by bending the stretch flange portion.

  The main part of the second pre-curl forming device 71 is shown in FIG. 12, and a portion for curling the body wall at the end of the body opening where the bent edge 69 is formed is opened outward in advance. It is bent into a round shape and formed into a flange shape, and has the function of pressing the entire bent edge 69 with an outer punch to further ensure the bending of the bent edge. The second pre-curl forming apparatus 71 has a lower die 81 fixed to a container holder 80 that opens and bends a curled portion of the barrel wall outward from the base end. A punch holder (not shown) is a container fitted to the container holder. An inner punch 82 and an upper die 83 are fixed so as to be fitted to the inner peripheral surface and sandwich the barrel wall with the container holder to prevent the barrel wall from buckling during curl molding. In the present embodiment, the inner punch and the upper die 83 are integrally formed as shown in the figure, but they may be formed as separate members as in the above embodiment. The punch holder is provided with an outer punch 78. In this second precurl molding device 71, the container 60 in which the bent edge 69 is formed by the first precurl molding device is fitted and held in the container holder 80, and the upper die is lowered together with the inner punch in this state. As shown in FIG. 12, the outer punch is bent outward at the position where the curl portion becomes the starting point, and the outer punch descends in that state, thereby crushing the bent edge portion and curling portion as shown in FIG. 13. The portion to be bent is bent in a substantially horizontal state to make the curl forming portion 73 into a flange shape.

As shown in FIGS. 14 and 15, the finished curl forming device 72 is for curling a curled portion that has been bent outwardly in a stretch flange shape by the second pre-curl forming device, and the pre-curl forming has been completed. It has a chuck 90 into which a rectangular shaped container is fitted, and a container support (not shown) that supports the container bottom fitted in the chuck. This finished curl forming apparatus is configured to perform finish curl molding in two stages, and a first curling roll 91 and a second curling roll 92 (FIG. 15) are arranged with a 180 ° phase shift across the chuck 90. ing. The first curling roll 91 and the second curling roll 92 are respectively formed with a first curling groove 93 and a second curling groove 94 in the circumferential direction. These curl forming grooves move in the radial direction while rotating relatively with respect to the flange-shaped curl forming part 73 having a bent edge formed at the tip held by the chuck. It is formed in a groove shape such that the portion is gradually wound inward along the forming groove. The first curl forming groove 93 performs the first-stage finish curl forming, and as shown in FIG. 14, the bent edge 69 is wound approximately 90 ° or more from the horizontal state to perform the curl forming to the intermediate state. Thus, the shape of the groove is formed. Then, as shown in FIG. 15, the second curl forming groove 94 formed on the second curling roll is for performing the finish curl forming following the first stage curl forming, and the sectional shape of the second curl forming groove. Is formed in a shape substantially similar to the outer shape of the curled portion of the container.
Each of the first curling roll 91 and the second curling roll can be heated to a predetermined temperature by a heater.

  In the finished curl forming apparatus, in order to perform the curling process over the entire circumference of the container, at least one of the container side fitted to the chuck 90 and / or the roll side of the first curling roll 91 and the second curling roll 92 is rotated. It is necessary to move and displace in the horizontal direction, but the roll may be moved along the curl forming portion 73 of the container while maintaining the above-mentioned phase, and the container is rotated by rotating the chuck. Also good. In that case, the 1st curling roll 91 and the 2nd curling roll 92 are comprised so that it may be displaced to a horizontal surface according to the change of the rotation radius of a container. In any case, the first curling roll 91 and the second curling roll 92 may be rotated freely about their axis (rotation) or may be forcibly rotated.

  The curling apparatus for a molded container according to this embodiment is formed as described above. In the case of a rectangular container, unlike the case of a circular container, there are a corner portion and a straight portion, and the density of each part is different. Therefore, the stress associated with the bending deformation acting on the container during curl processing is different, and it is difficult to curl the entire circumference at the same time, but according to this embodiment, the pre-curl process and the finish curl process In the pre-curling process, the entire circumference is performed simultaneously, and only the finishing curl process is performed by a curling roll as in the conventional case. As described above, according to the present invention, in the case of a rectangular container, a bent edge portion with a strong crease is forcibly formed in the precurl process in the same manner as in the case of a cup-shaped container, and is wound into the curled portion. Therefore, even in the case of a rectangular container, it is possible to easily perform curl molding, and to perform good curl molding with excellent shape retention.

The cup shown in the photograph in FIG. 16 having a diameter of 58.2 mm and a depth of 43 mm by drawing and ironing from a paper board (total thickness 0.38 mm) laminated with a low-density polyethylene film (LDPE film) on the inner and outer surfaces of the paper substrate. A primary molded cup container was obtained. When the density of the trunk wall of the obtained primary molded container was measured, it was 0.82 g / cm ³ near the bottom of the trunk wall and 1.63 g / cm ³ near the opening end. Near the edge, the density is about twice that of the bottom. This is because the vicinity of the opening end portion is shrink-formed by drawing ironing. Using the curl forming area from the opening of the primary molding container to a depth of about 12.7 mm, the precurl processing for forming the bent edge 6 of the curl portion by the precurl molding device and the finishing curl molding device shown in FIGS. 5 and 6 Then, a finish curling process was performed to obtain a cup-shaped drawn and ironed container having a curled portion at the end of the body opening as shown in FIG. As a result of repeating the experiment, the curl formability during finish curl molding is affected by the molding temperature and molding speed, the molding temperature is preferably 90 ° C or higher, and the molding speed tends to be easier when the molding speed is lower than 200 mm / s. I found out. Therefore, in this example, the finish molding process was performed at a molding temperature of 120 ° C. and a molding speed of 200 mm / s.
Each dimension of the pre-curl molding apparatus and the finish molding apparatus was set as follows.
Precurl molding equipment:
Upper die radius of curvature R ₁ : 1.81 mm
Lower die radius of curvature R ₂ : 1.40 mm
Finishing molding equipment:
Curvature radius of molding die R ₁ = 1.40 mm, R ₂ = 2.00 mm
Curling radius of curvature R ₃ = 1.40 mm
Curling height H = 3.39mm
Ten curls were molded using the molding apparatus as described above, and the dimensions of the curled portion of the resulting container were measured. The average value of the measurement results was as follows.
Bending edge width a: 1.9 mm
Curled part height b: 11.6 mm
Curled part width c: 4.3 mm
Container curl outer diameter: 71.5 mm
Container height: 30.3mm
Further, as a comparative example, without performing the pre-curl molding process, the direct curl molding was performed on 10 pieces in the same manner as in the example using the finish curl molding apparatus of FIG. 5 as in the conventional cup curl molding process. . The average value was as follows.
Curled part height b: 11.7 mm
Curled part width c: 4.4 mm
Container curl outer diameter: 72.3 mm
Container height: 30.3mm

  As is clear from the above results, in the case of the example, the dimension of the curled part after molding almost coincides with the dimension set by the molding apparatus, and the curl is molded into a good shape without loosening the curled part. It was confirmed that the shape retention was excellent. On the other hand, in the case of the comparative example, the curled portion loosens when taken out from the device after molding, and the curled portion height b and width c are larger than the set dimensions of the molding device, and the shape retention is poor and the curl is good. Was not obtained. In addition, in the case of the example, the surface of the curled portion also maintains a good surface shape by maintaining uniform fine wrinkles, but in the case of the comparative example, partial wrinkles are uneven and The shape was inferior. 18A and 18B are enlarged cross-sectional photographs of curled portions of containers of Examples and Comparative Examples, where FIG. 18A is an example and FIG. 18B is a comparative example. As is clear from this photograph, the embodiment is wound inward so that the bent edge portion is located in the curl portion, the curl portion has a small radial thickness, and the curl is formed in a compact shape without loosening. On the other hand, in the comparative example, the entire curled portion is slack compared to the example, and in particular, the radial thickness is larger than that of the example, and a good winding state is not obtained. I understand.

  According to the present invention, it is possible to form a curled portion of a draw-contained container or a squeezed and iron-formed container mainly made of paper, which has been difficult to curl, with good shape retention. It becomes possible to mold with almost the same dimensional accuracy as a molded container, making it possible to apply paper molded containers to various uses including beverage containers, and to apply containers with excellent environmental adaptability. The present invention can be applied not only to paper but also to curl molding of resin molding containers.

(A) is front sectional drawing of the cup-shaped molded container which concerns on embodiment of this invention, (b) is an enlarged view of the curl part. It is a schematic diagram which shows the formation process of the curl part. It is a partially broken front view of the square drawing molded container which concerns on embodiment of this invention. FIG. It is principal part front sectional drawing of the pre-curl shaping | molding apparatus which comprises the curl shaping | molding apparatus which concerns on embodiment of this invention. It is principal part front sectional drawing of the finish curl shaping | molding apparatus which comprises the curl shaping | molding apparatus which concerns on embodiment of this invention. FIG. 6 is an enlarged front sectional view of a main part of the precurl molding apparatus shown in FIG. 5. FIG. 7 is an enlarged front sectional view of a main part of the finishing curl forming apparatus shown in FIG. 6. It is principal part front sectional drawing showing the state before the shaping | molding start of the 1st precurl shaping | molding apparatus which comprises the curl shaping | molding apparatus which concerns on other embodiment of this invention. It is principal part front sectional drawing in the state which formed the extension flange. It is principal part front sectional drawing in the state which formed the bending edge part. It is principal part front sectional drawing in the state which bent the curl formation part of the 2nd pre curl shaping | molding apparatus which comprises the curl shaping | molding apparatus which concerns on other embodiment of this invention. It is principal part front sectional drawing in the state which crushed the bending edge part. It is principal part front sectional drawing showing the curl molding state by the 1st curling roll of the finish curl shaping | molding apparatus which comprises the curl shaping | molding apparatus which concerns on other embodiment of this invention. It is principal part front sectional drawing showing the curl molding state by the 2nd curling roll of the finishing curl apparatus which comprises the curl molding apparatus which concerns on other embodiment of this invention. It is the photograph from the perspective direction showing the curl unprocessed state which finished the primary shaping | molding of the cup-shaped shaping | molding container which concerns on the Example of this invention. It is the photograph from the perspective direction of the cup-shaped molded container showing the state after curl processing. It is a photograph of a curl section, (a) is an example and (b) is a comparative example.

DESCRIPTION OF SYMBOLS 1 Cup-shaped molded container 2 Bottom wall 3 Trunk wall 5, 65 Curl part 6, 69 Bending edge part 8, 68 Stretch flange 10 Pre-curl molding apparatus 11 Die holder 12 Container holder 13 Lower die 15, 35 Punch holder 6, 36 Inner Punch 17 Outer punch 18 Upper die 19, 20, 39 Spring 21 Convex molding surface 22 Concave molding surface 23 Cylindrical surface 24 Cylindrical outer peripheral surface 25 Annular taper introduction part 26 Outer peripheral surface 27 Tip edge 30 Finish curl forming device 31 Die holder 32, 75 , 80 Container holder 33 Curling die 37 Molding die 41 Curl molding surface 42 Arc shaped molding surface 43 Resistive heater 60 Square drawing container 61 Corner portion 62 Straight portion 63 Trunk wall 64 Bottom wall 65 Projection 66 Reinforcement rib 67 Curling portion 70 First precurl molding device 71 Second precar Curl forming device 72 Finish curl forming device 76, 82 Inner punch 77, 83 Upper die 78, 84 Outer punch 81 Lower die 90 Chuck 91 First curling roll 92 Second curling roll 93 First curl forming groove 94 Second curl forming groove

Claims (2)

  A molded container formed by drawing or drawing and squeezing and forming a sheet material mainly composed of a paper having a barrel part and a bottom part integrally formed with a curl part at an opening end part of the trunk part, wherein the curl shape of the curl part has a trunk part A bent edge is formed by bending downward from the bent base end, which is an inner side of a predetermined width, from the end of the extended flange formed to extend outward from the open end, and is wound so that the bent edge is positioned within the curled portion. The molded container is characterized in that the tip of the bent edge portion is located in the curl portion toward the outer side of the body portion.   The molded container according to claim 1, wherein the molded container is a cup-shaped or tray-shaped container.