JP4975074B2 - Method for producing food packaging container - Google Patents

Description

In the present invention, a synthetic resin sheet material is swelled, and the container body and the lid are integrally connected via a folding hinge portion, and accommodates food such as vegetables, fruits, confectionery, and eggs. it a food packaging container which may, to a method of manufacturing a container with a structure in which the container itself is provided with the sealing portion.

  Food packaging containers formed by bulging and molding such synthetic resin sheet materials are generally well known, but many of them have their free end edge portions sealed with a sealing tape between the container body and the lid. . After purchasing the product, the seal tape is peeled off, opened, and a portion of the food is taken out. Then, in order to preserve the remaining products, the lid is folded from the folding hinge and placed on the container body. The whole container is covered with a rubber band and covered in a refrigerator or the like. However, in order to take such a method, it is necessary to always have a rubber band, and it is necessary to always keep the rubber band close to hand, and if the rubber band is not found, the container cannot be kept closed. It was supposed to be large and bulky.

  In view of such a situation, as described in Patent Document 1, the container body 1 and the lid body 2 can be used as a means for easily closing the container once opened without requiring a rubber band or the like. On the one hand, the engagement recess 12 is formed on the horizontal surface 11 surrounded by the four egg-containing recesses, and the engagement protrusion 22 that engages with the engagement recess 12 is formed on the other. At the time of closing the lid after opening the container at one end, the engagement concave portion 12 and the engagement convex portion 22 are pressed with the fingertips and engaged in a hook shape to maintain the closed posture. It is publicly known.

  Further, as described in Patent Document 2, a projection 4 is formed on one of the free end edges of the container body 1 and the lid 2, and a fitting recess 5 for receiving the projection 4 is formed on the other. In addition, a container closing posture maintaining structure in which the protrusion 4 and the fitting recess 5 are pressed against each other by a fingertip when the container is closed after the container is opened has also been developed and known as a food packaging container. It has become.

JP 2002-234520 A JP 2004-323056 A

  However, in these prior known techniques, a circular granular protrusion is formed on one of the container body and the lid, and a circular granular recess is formed on the other, or a short length close to the circular granular protrusion is formed. The granular protrusions and the granular recesses of the same shape are formed, so that these granular protrusions and granular recesses have a tapered shape for engagement because of the fact that the container is a sheet molded product. There is a need to keep it in place, and when molding the container, it is necessary to forcibly remove it from the mold, and because the wall thickness becomes extremely thin due to bulging molding, the fitting force between the protrusion and the recess is strengthened It is difficult to maintain the container closing posture for a long time, and in particular, when the mating release and mating are repeated a plurality of times, the mating ability is extremely reduced, and the container lid is closed. The problem to be solved that the posture maintenance becomes difficult It has become a thing to be.

Therefore, the present invention eliminates a fitting projection structure for forming a single part or two bodies of a circular granular shape or a small unevenness close to a granular shape as a fitting portion for maintaining the closed posture between the container body and the lid. and, also, to reject forced bleeding from thickens shape and mold the fitting protrusions, while a resin sheet molded container, be repeated a plurality of times and disengagement and engagement of the fitting portion fitting capacity without extremely reduced, and an object thereof is to provide a method for producing food packaging containers can be kept to maintain the closed position of the container with confidence.

The requirement concerning the method for manufacturing a food packaging container according to the present invention taken to solve this problem is that the synthetic resin sheet material is bulged and the container body 1 and the lid body 2 are bent and the hinge part 3 is bent. Using a sheet in which a material sheet is stretched in one direction, either vertically or horizontally, and a stretching direction of the one-way stretched sheet; , A step of arranging a sheet on the container molding die B so that the arrangement direction of the container body 1 and the lid body 2 is the same direction, and the container molding die B is formed with the container body molding portion 10 and the lid body molding. The free end edge forming portions 10a, 20a with the portion 20 are provided with either the ridge forming portion 40 extending along the longitudinal direction or the groove forming portion 50, and simultaneously with the bulge forming of the container portions 1, 2, 3 4 or 4 on the free end edges 1a, 2a of the container body 1 and the lid 2 A step of bulging the bag, and then heating the entire molded container or at least one free end edge 1a, 2a to release the stretch tension state of the free end edge 1a, 2a and And a process including processing to make the width of the projecting bases 41 and 51 of the projecting ridge 4 or the groove 5 subjected to the thermal contraction in the direction to be narrower than the width of the projecting tip side parts 42 and 52. After that, a food packaging container is manufactured.

In the food packaging container according to the present invention, the container main body and the lid in the container are juxtaposed in the extending direction of the sheet, and the free end of the container main body and the lid is connected to the free end. A ridge extending along the longitudinal direction of the edge is formed, and a groove that extends along the longitudinal direction of the free end edge and fits with the ridge is formed on one of the other free end edges. The cross-sectional shape of the ridge is formed so that the width of the protruding base is smaller than the width of the tip side portion, or the cross-sectional shape of the groove is concave compared to the width of the concave bottom side portion. Either the width of the base portion is formed to be small, or it is assumed to have both of these structures, so that these ridges and grooves are extended along the longitudinal direction of the free end edge portion. It is not a thing that was formed with a tapered shape and was forcibly removed from the mold, but the base was narrowed by post-processing These ridges and grooves are excellent in compressive strength, and even if the mating release and mating are repeated several times, the mating ability will not be drastically reduced, and the container closing posture can be maintained with peace of mind. It is intended to produce a container that has an effect that cannot be expected from the conventional container.

Further, when manufacturing a container having such an effect, when the container main body and the lid body are swelled, protrusions and grooves are formed on the free end edges of both bodies along the longitudinal direction of the free end edges. By forming the container at the same time, heating the entire container or the free edge by post-processing after forming the container, and adding the process of narrowing the base of the ridge and the groove in the width direction, the material in advance The stretch tension state of the free end edge due to the sheet being stretched is released and thermally contracted in the width direction. By this heat shrinking process, the width of the protruding base of the ridge or groove is changed to the protruding tip side. By processing so that it is narrower than the width of the part, as described above, the ridges and grooves are excellent in compressive strength, and the fitting ability can be achieved even if fitting release and fitting are repeated several times. Capable of maintaining a closed position with peace of mind without causing extreme degradation Ru manufacturing method der can be obtained easily.

The perspective view which shows the surface shape of a raw material sheet | seat and a shaping die. The perspective view which shows the surface shape of another raw material sheet | seat and a shaping die. The perspective view which shows the open lid shape of a shaping | molding container. The perspective view which shows the open lid shape of another container. The longitudinal cross-sectional view before shaping | molding of a shaping die. The longitudinal cross-sectional view of the shaping | molding state of a shaping die. The longitudinal cross-sectional view which shows the cover open state of the container after shaping | molding. The longitudinal cross-sectional view which shows the closed state of a completion container. The expanded sectional view which has arranged the free end edge part of a forming container up and down. The expanded sectional view which arrange | positioned the post-processed free end edge part up and down. The expanded sectional view which showed the fitting state of a protruding item | line and a ditch | groove. The upper-lower arrangement expanded sectional view of the free end edge part after the post-processing of the container of another Example. The expanded sectional view which showed the fitting state of the protruding item | line and the ditch | groove of the Example. Furthermore, the up-down arrangement | positioning expanded sectional view of the free end edge part after the post-processing of the container of another Example. The expanded sectional view which showed the fitting state of the protruding item | line and the ditch | groove of the Example. The perspective view equivalent to FIG. 3 which shows the container of another Example of a protruding item | line and a ditch | groove.

  In carrying out the present invention, one of the free end edges of the container body 1 and the lid body 2 referred to in the construction of the container is provided with a ridge extending along the longitudinal direction, and the other is provided with this protrusion. Concave grooves that fit together with the strip are formed at the same time as the container is formed. This shape does not have a cross-section upside down trapezoidal shape that requires forcible removal from the mold, or a deepened shape like the dovetail shape or dovetail shape. The free end edge is heated by post-processing after forming the container, and is thermally contracted using the restoring action of the material sheet by stretching. By post-processing, the cross-sectional shape of the ridges and grooves is secondary processed so as to be upside down trapezoidal, dovetail and dovetail, so that these ridges and grooves are not weakened. Is preferred.

  In addition, it is preferable that both the ridges and the grooves are processed in the heat shrinking process by heating the free edge, but only one of them is processed to make frictional contact with the other ridges or grooves. In this way, it can be implemented as a shape that is not easily removed.

  It is preferable to use a synthetic resin sheet material such as PET (polyethylene terephthalate), which has been conventionally used for the molding material of the container, in that it can be easily restored and contracted by heating during secondary processing as post-processing. .

  Embodiments of the present invention will be described below with reference to the drawings. The container for food packaging shown in the embodiment is formed by bulging and forming a sheet material made of polyethylene terephthalate resin, as is generally known, and the container main body 1 and the lid 2 and the folding hinge portion positioned therebetween. 3 is an example of a container for egg wrapping that is integrally formed with No. 3. In addition, as a sheet material to be used, a sheet that has been unidirectionally stretched in the width direction or the longitudinal direction of the sheet is used. This stretching process only needs to be performed before the sheet is supplied to the molding die.

  FIG. 1 shows a surface shape of a mold B for forming a container as a sheet material S in a state where a sheet before forming is stretched only in a width direction indicated by an arrow W and a sheet is transmitted below the sheet. Is. In this sheet material S, the molding die B is arranged in the width direction of the die from the left side to the right side in the die shown in the figure, the lid molding die part 20, the hinge part molding die part 30, Used for molds arranged with the container body mold part 10. In other words, as shown in the drawing, the sheet material S that has been stretched only in the width direction is a mold in which the other parts 10 and 20 are arranged in parallel in the left-right direction across the hinge part mold part 30. Use as a target.

  FIG. 2 shows a sheet material S as a sheet material S before being formed by stretching only in the longitudinal direction indicated by an arrow L, and a container molding die B in a state where the sheet is transmitted under the sheet, as described above. The surface shape is shown. This sheet material S is arranged in the front-rear direction of the molding die B, and in the mold shown in the figure, from the back side toward the front side, the lid molding die part 20, the hinge part molding die part 30, the container. Used for molds arranged with the main body mold part 10. In other words, in the sheet material S that has been stretched only in the longitudinal direction of the sheet, as shown in the drawing, the other portions 10 and 20 are in the direction between the front side and the back side with the hinge portion molding die portion 30 in between. The molds arranged in are used as targets.

  FIG. 3 illustrates a container A molded using the molding die B having such a structure. The container shown here is a container for egg wrapping in which a recess 11 for partitioning and packaging 10 eggs is formed in the container body 1 and a recess 21 covering the upper part of the egg is formed in the lid 2.

  However, the container referred to in the present invention is not limited to a container for egg wrapping, but is formed in the product housing recess 11 and the lid 2 formed in the container body 1 as illustrated in FIG. Even a container in which the product covering concave portion 21 is formed in a substantially rectangular shape can be molded in the same manner.

  Thus, the molding die B according to the present invention includes the free end edge 1a of the container body 1 in the upper die B1 and the lower die B2, as shown in FIGS. A groove-like concave portion 41 and a rib-like projection 42 that are loosely fitted to each other are formed at opposing portions of the mold portions 10a and 10b on the side that forms the rim, and the free end edge portion 2a of the lid body 2 is Similarly, rib-shaped protrusions 51 and groove-shaped recesses 52 that are loosely fitted to each other are formed at the opposing positions of the mold parts 20a and 20b in the upper mold B1 and the lower mold B2 on the side to be formed. ing.

  Reference numerals 61 and 62 shown in FIGS. 5 and 6 are male mold portions protruding upward from the upper surface of the lower mold B2, and reference numerals 63 and 64 are provided from the lower surface of the upper mold B1. It is the female side cavity part for male mold part receptions pierced upwards. In addition, the code | symbols h and d are the codes | symbols which show height and depth for container main body side formation, respectively, and ch and cd are for cover body side formation.

  Needless to say, these molding dies B shown in FIGS. 5 and 6 include mold parts (10a and 10b, 10a and 10b) for forming free end edges 1a and 2a between the container body 1 and the lid 2 in the container. 20a and 20b) may be any one in which either one of the groove forming mold portions 41, 42 or the protrusion forming mold portions 51, 52 is formed as a pair.

  Thus, the concave groove forming mold parts 41 and 42 and the protruding line forming mold parts 51 and 52 shown in FIGS. 5 and 6 are forcibly removed from the mold B. In order not to be necessary, the cross section is U-shaped or V-shaped close to the U-shape. Here, a U-shaped cross section is shown. A container A molded by this mold B is shown in FIG.

  After the container normally formed in this manner is heated, the entire container is heated, or only the free end edge 1a of the container body 1 is heated according to circumstances, or the free end edge of the lid 2 is used. Only 2a is heated, or both edges 1a, 2a are heated, and the heated free end edge 1a or 2a or both edges 1a, 2a are to be restored and contracted by being stretched. The free end edge portions 1a and 2a are subjected to post-processing that is thermally contracted in the width direction by utilizing the contraction action of the sheet on which the acting force acts.

  Regarding the post-processing of the free end edge portions 1a and 2a of the container body 1 and the lid 2, the cross-sectional shapes of the ridges 4 and the grooves 5 before processing are shown in FIG. FIG. 10 shows the cross-sectional shape of FIG. 10, and FIG. 11 shows the cross-sectional shape of the processed protrusion 4 and the groove 5 fitted together.

  First, as shown in FIG. 9, the protrusions 4 and the recesses bulged and formed along the longitudinal direction of the free end edges 1 a and 2 a of the container body 1 and the lid body 2 by the molding die B described above. The cross-sectional shape with the groove 5 is a U-shaped cross section. As a result, the free end edges 1a, 2a are removed from the molding die B without forcibly removing them, so that the protrusions 4 and the grooves 5 of the free end edges 1a, 2a are locally extremely thin. It is prevented from being brought into a state, and is formed with ridges 4 and grooves 5 having substantially uniform thickness.

  After doing so, on both sides of the ridges 4 and the grooves 5 connected to the recessed bases 41 and 51, that is, the left and right flat surfaces in the figure, a heating booth in which a heater is embedded, or radiant heat of electric heat Is heated by passing through the irradiation region, and the flat surface is thermally contracted only in the width direction of the free edge portions 1a and 2a. By this step, as shown in FIG. 10, the width of the ridges 4 and the grooves 5 is made to be larger than the width of the bulging tip side portions 42 and 52, that is, the width of the bulging base side portions 41 and 51. Is transformed into a small one. Thereafter, the container is completed by processing.

  In order to use the container A thus obtained, after the required goods are accommodated in the container, the upper and lower portions of the ridges 4 and the grooves 5 are pressed, as shown in FIG. , 5 are closed. After this, another seal such as using wrap packaging or other well-known means, if necessary, for the occurrence of accidents such as personal opening during the distribution channel of the product or during the exhibition, and for product protection in terms of hygiene You just have to take a sealing measure.

  Thus, when the merchandise purchaser opens the container for taking out the merchandise and stores the remaining contents after taking out the required merchandise, as described above, the ridges 4 and the concave grooves are used. By pressing and fitting the upper and lower portions with 5, the container can be sealed again. At this time, since the sealing action part is not a small point or a circular shape, but fits the ridge 4 and the groove 5 extending along the free end edge of the container, it is sealed securely and reliably. Can be kept sealed. This sealed state is shown in FIG.

  12 and 13 show another embodiment of post-processing of the ridge 4 and the groove 5. As shown in FIG. 12, the post-processing is not performed on the ridges 4 as shown in FIG. Only the width of the proximal end portion 51 is processed to be narrow. Thus, when both the parts 4 and 5 are fitted, as shown in FIG. 13, the ridge 4 is narrowed while receiving a resistance to the bulging proximal end portion 51 of the groove 5, and enters the groove 5. It enters and comes into close contact with each other, preventing easy movement of both parts 4 and 5.

  On the contrary, as shown in FIG. 14, the ridges 4 and the grooves 5 are formed to have substantially the same shape and size, the grooves 5 are not processed, and the bulging base end of the ridges 4 is formed. When only the width of the side portion 41 is processed to be narrow and both the portions 4 and 5 are fitted, the tip side portion 42 of the ridge 4 is in close contact with the inner surface of the groove 5 as shown in FIG. In this way, easy movement of both the parts 4 and 5 may be prevented.

  Further, the ridges 4 and the grooves 5 extending along the longitudinal direction of the free end edge of the container are convex portions extending over the entire length of the free end edge as shown in these embodiments. The strip 4 and the concave groove 5 are not necessarily required. For example, as shown in the schematic shape of FIG. 16, the strip 4 may be divided into a plurality of pieces in the longitudinal direction of the free end edge. Even if it does in this way, since the protruding item | line 4 and the groove 5 shown here are made into the shape extended along the longitudinal direction of a free end edge, even if it is a free end edge of a narrow width | variety, sufficient The fitting force can be maintained.

  As mentioned above, although the Example considered to be typical of this invention was described, this invention is not necessarily limited only to what was shown to these Examples. For example, regarding the container, the container is not limited to eggs packaging containers, but can be applied to various food packaging containers such as fruits and confectionery, achieving the above-described object of the present invention, The present invention can be implemented with appropriate modifications within the range having the above-described constituent elements and having the effects of the present invention.

  In the container according to the present invention, the ridges and grooves used for sealing are not forcibly removed from the mold at the time of molding, but are made into an interfitting structure by post-processing. It can be used conveniently and is considered to be very popular.

A Container B Mold S Sheet material W Arrow L Arrow 1 Container body 1a Free end edge of the container 2 Lid 2a Free end edge of the cover 3 Bending hinge part 4 Convex strip 41 Convex tip end portion 42 Convex strip Base end portion 5 concave groove 51 tip end portion 52 of concave groove base end portion of concave groove 10 container body molded portion 10a free edge forming portion 20 lid forming portion 20a free edge forming portion 40 ridge forming portion 41 convex Projection base 42 of the protrusions Projection tip side part of the protrusions 50 Concave groove forming part 51 Projection base part of the groove 52 Projection tip side part of the groove

Claims (1)

A method of producing a food packaging container in which a container body (1) and a lid body (2) are integrally formed through a bent hinge portion (3) by bulging and molding a synthetic resin sheet material. Because
Using a sheet in which the material sheet is stretched in either the vertical or horizontal direction so that the stretching direction of the one-way stretched sheet is the same as the arrangement direction of the container body (1) and the lid (2). A step of placing a sheet on the container molding die (B), and the container molding die (B) includes a free edge forming portion (10a) between the container body molding portion (10) and the lid molding portion (20). 20a) is provided with either a ridge forming part (40) or a groove forming part (50) extending along the longitudinal direction, and at the same time as the container part (1, 2, 3) is bulged, the container body (1) a step of bulging the protruding edge (4) or the groove (5) on the free end edge (1a, 2a) of the lid (2), and then the whole molded container, At least one free end edge (1a, 2a) is heated to release the stretched tension state of the free end edge (1a, 2a) and thermally contracted in the width direction, and the thermal contraction (4 ) Or the width of the projecting base (41, 51) of the groove (5) is narrower than the width of the projecting tip side part (42, 52). Method for producing a food packaging container, which comprises a step of processing such.

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