JP6670210B2 - Packaging container and manufacturing method thereof - Google Patents

Description

  The present invention relates to a synthetic resin container mainly used for transportation and packaging, and a method for producing the same. In particular, a synthetic resin container having liquid tightness (for example, mechanical parts coated with oil for rust prevention, , A tray or the like for transporting or packaging a container to which a liquid is attached or immersed, such as an ornamental flower or the like supplied with a liquid. It relates to the manufacturing method.

  2. Description of the Related Art Conventionally, there has been known a packaging container formed by using a plate-like sheet made of a thermoplastic resin and heat-sealing components such as a bottom plate and a side plate for the purpose of transporting and / or packaging products or parts. is there.

  As such a packaging container, for example, a plastic corrugated cardboard sheet having thermoplasticity and heat fusibility is used, and a plastic having at least one joint portion obtained by joining the cut ends of the plastic corrugated cardboard sheet is used. In the corrugated cardboard box, the joint portion starts from the plastic corrugated sheet by thermoplastic deformation on the upper or lower surface of both cut ends of the plastic corrugated sheet to be joined to each other at least from the surface of the plastic corrugated sheet. A slope is provided over the entire thickness of the hollow region sandwiched between the liners, which are structural members of the corrugated cardboard sheet, and a liner on the surface of the plastic corrugated cardboard sheet on the side where the slope is provided is stretched on the slope. A liner covering the hollow area exposed at the cross section of the cut end Forming a plastic melting layer on the surface portion by heating and melting the surface portion of the liner coating layer, and contacting the melting layers on both slopes with each other to form the plastic corrugated cardboard sheet; 2. Description of the Related Art A plastic corrugated cardboard box is known, which is formed by fusing using a heat fusing property, cooling and solidifying the fused layer, and fusing the slopes together (for example, Patent Document 1). 1).

  The packaging box (plastic corrugated cardboard box) according to Patent Document 1 described above has a good appearance in appearance without using metal fasteners or the like at the joints because the components are heat-sealed and become strong. It is excellent in that it can be done. However, in the packaging box, the corners do not become a right angle unless the tapered end faces of all adjacent side plates are securely joined to each other. For this reason, it is difficult to ensure the accuracy of the product. In addition, in order to join the corners at a right angle, not only a step of bending the side plate with respect to the bottom plate but also a step of separately joining the tapered end surfaces is required, and the assembling work may be complicated. . Further, since the plate-like sheet is melted by the grid-shaped hot plate, a hot plate having a different size is required according to the size of the developed view in the packaging box, which may lead to an increase in manufacturing cost. .

  Therefore, the present applicant has solved such a problem, and is a packaging box having watertightness, durability, and load-bearing ability. In particular, it is possible to improve the accuracy of each corner and easily assemble the box. As a packaging box and a method for manufacturing the same, a joining piece is secured at a predetermined position from both right and left ends of one thermoplastic resin plate with four corners cut out, and a bent groove formed by heat melting at a boundary between the bottom plate and the first side plate. A first bending step of bending and fusing the first side plate above the bottom plate, and fusing left and right end surfaces of the first side plate and end surfaces of the joining pieces; and A bent groove formed by heat melting is provided on the joint piece to form the second side plate and bend upwardly of the bottom plate, and end faces of the bent groove, right and left end surfaces of the first side plate and the joint piece are formed. A second bending step of fusing and joining the end faces. Method for producing a wear box offering, and a packaging box which is the product (for example, see Patent Document 2.).

JP 2010-285212 A Japanese Patent No. 5269947

According to the method for manufacturing a packaging box according to Patent Literature 2, provision of a packaging box having a certain degree of watertightness, durability, and load resistance has been realized.
However, on the other hand, in the packaging box according to Patent Document 2, although a certain degree of watertightness is recognized, a highly reliable watertightness over a longer period is required.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a packaging container and a method for manufacturing the same, which can increase the reliability of liquid tightness.

The present invention includes a bottom plate made of a non-foamed or low-foamed synthetic resin, and side plates integrally formed on a peripheral edge of the bottom plate, and a sleeve portion at a side end of one of the side plates adjacent to each other. A side end of the other adjacent side plate has a joining end that can be brought into contact with the sleeve, and a gap is provided at a boundary line where the sleeve and the joining end of each side come into contact. In the container, the bottom plate and each side plate are non-foamed or the low-foaming synthetic resin having an expansion ratio of 8 or less, and one side plate having a joint end portion of each side plate is a front side plate positioned forward, and the front side plate is The side plate facing the rear side plate is located at the rear, the right side plate is viewed from the front side and the right side plate is viewed to the right, and the left side plate is viewed from the front side and the rear side is viewed. and left side plate located to the left, the sleeve piece is inclined from the base end at its end face The joining end portion has another inclined surface inclined from the base end side at the end surface and another vertical surface continuous with the other inclined surface. And a first notch formed in advance by the inclined surface of the sleeve portion and the other inclined surface of the joint end, and a left and right first notch in the front side plate. In the above, the line passing through the position behind the tip where the inclined surface and the other inclined surface are connected, and the left and right first notches in the rear side plate, the inclined surface and the other inclined surface are connected. Lines passing through the front position from the tip to be made, respectively, as a first virtual line, in the vicinity of the first notch and the position between the first notch and the first virtual line A surplus portion formed in advance, wherein the surplus portion is melted, and the sleeve portion and the joining end are fusion-joined. A ridge-shaped closed portion having a filling portion formed by filling the gap with the molten surplus portion on at least either the outer surface side or the inner surface side of the boundary line by being formed, The container for use is a means for solving the above-mentioned problem.

In the present invention, on the premise of the above invention , the pair of side plates facing each other includes the sleeve portion on the lower side of both ends thereof, and is continuous from an upper position of the sleeve portion to an adjacent side surface. Means for solving the above-mentioned problem, comprising: a packaging container, comprising: a side support portion; and a second side plate fixed to an inner surface of the side support portion on the adjacent side surface. And

  Further, the present invention is based on the premise that the second side plate is made of a plastic cardboard having a plurality of parallel ribs between two component plates, and the longitudinal direction of the ribs is vertically arranged. A packaging container characterized by the above is a means for solving the above problems.

  Further, the present invention provides a packaging container characterized by comprising a reinforcing frame portion and a reinforcing corner portion for reinforcing an upper end portion, on the premise of the configuration of any of the above inventions, and a means for solving the above problems. I do.

Also, the present invention provides a packaging container for heating and melting the mutually end faces of adjacent side plates of a low-foam synthetic resin or non-foam synthetic resin sheet having a bottom plate and respective side plates formed integrally with the periphery of the bottom plate. In the manufacturing method, the synthetic resin sheet is a low-foam synthetic resin sheet or a non-foam synthetic resin sheet having an expansion ratio of 8 times or less, and a sleeve end portion is provided at a side end of one of the side plates adjacent to each other, and the other is adjacent to the other side plate. A side end of the side plate is provided with a joint end that can be brought into contact with the sleeve , and the sleeve has an inclined surface inclined from a base end side at an end surface thereof and a vertical surface continuous with the inclined surface. The joint end has another inclined surface inclined from the base end side at the end surface thereof and another vertical surface continuous with the other inclined surface, and the joint end is joined to the inclined surface of the sleeve portion. A first cut formed in advance by said other inclined surface at the end; Part constitute, to the first notch of two positions which V-shaped tip of the plurality of first cut-out portion is the same direction, the line passing through the center position closer than the V-shaped tip end of the two portions As a first virtual line, a sheet having an adjacent portion of the first notch and a surplus portion formed in advance between the first notch and the first virtual line, Heated and melted in one virtual line, the side plate including the first notch portion and the surplus portion that is not in a molten state , the sleeve portion and the joining end are erected, and below the first notch portion, between the first virtual line positioned below the first cut-out portion of the proximal part and the first notch, a step prior to securing the surplus portion is not in a molten state, said first notch straight to the first imaginary line in said sheet, wherein the surplus portion is formed And, in a second imaginary line passing through two opposing first cutouts, the sleeve is welded to the joint end by heating and melting, and the melted surplus part is at least outside the side plate. Or the first step to protrude inward, the excess portion in the molten state that protrudes, presses from at least one of the outside or the inside of the side plate, fills the gap portion of the boundary line as a filling portion, a ridge-shaped closing portion. A method for producing a packaging container, comprising: a second step of forming the container; and a method for solving the above-mentioned problem.

  According to the present invention, there is provided a bottom plate made of a non-foamed or low-foamed synthetic resin, and each side plate integrally formed on a peripheral edge of the bottom plate, and a sleeve portion is provided on a side end of one of the side plates adjacent to each other. The other end of the adjacent side plate is provided with a joining end that can be brought into contact with the sleeve portion, and a gap is provided at a boundary line where the sleeve and the joining end of each side plate come into contact with each other. In the packaging container, the bottom plate and each side plate are non-foamed or the low-foamed synthetic resin having an expansion ratio of 8 or less, and at least one of the outer surface and the inner surface of the boundary line is filled in a gap. Since it has a ridge-shaped closing part having a part, the ridge-shaped closing part closes a minute gap formed at the boundary line, thereby preventing leakage of fluid to the outside and improving liquid tightness. Can hold.

  Further, according to the present invention, in addition to having the above configuration, the filling portion in the closing portion has a sleeve portion or a joint end of at least one of the side plates made of the low-foaming synthetic resin or the non-foaming synthetic resin. Since the surplus portion is formed, the surplus portion is filled into the gap portion by melting under heat, so that processing is easy, the gap can be reliably closed, and liquid tightness can be maintained.

  According to the present invention, in addition to the provision of the above-described configuration, the surplus portion includes a portion near the first cutout formed over the sleeve portion and the joining end, and a portion near the first cutout. Since it has been provided between the first virtual lines located below, it is possible to secure a surplus portion from the first notch to the height between the first virtual lines, so that a sufficient amount of resin to constitute the filling portion , The gap can be reliably closed, and the liquid tightness can be maintained. Further, by providing the first notch, the amount of resin required for welding can be melted while reducing the amount of resin to be melted.

  In addition, according to the present invention, in addition to having any one of the above-described configurations, the pair of opposing side plates includes the sleeve portion on the lower side of both ends thereof, and from a position above the sleeve portion. A ridge-shaped closing portion that closes a boundary line because a side support portion that is continuous to an adjacent side surface is provided, and the adjacent side surface includes a second side plate that is fixed to an inner surface of the side support portion. Accordingly, there is an advantage that the storage amount can be secured while securing a height that can maintain liquid tightness.

  According to the present invention, in addition to the above configuration, the second side plate is made of a plastic cardboard having a plurality of parallel ribs between two component plates, and the longitudinal direction of the ribs is arranged in a vertical direction. With this configuration, the strength of the side plate can be increased by the second side plate, and the buckling strength of the entire packaging container according to the present invention can be increased.

  Further, according to the present invention, in addition to having any one of the above-described configurations, since the reinforcing frame portion and the reinforcing corner portion for reinforcing the upper end portion are provided, the distortion between the side plates causes the reinforcing frame portion of the upper end portion and the distortion. Since the restriction is performed by the reinforcing corners, the strength of the entire packaging container according to the present invention can be increased. Further, a plurality of the packaging containers can be stacked.

  Further, according to the present invention, in the method for producing a packaging container made of a thermoplastic synthetic resin and joining the end faces of adjacent side plates by heating and melting, the thermoplastic resin is a low-foam synthetic resin having an expansion ratio of 8 times or less. Or, it is a non-foamed synthetic resin, and includes a surplus portion at a joining portion including the end face of at least one side plate, and abuts the joining portions in a molten state with each other to protrude the surplus portion at least outside or inside the side plate. The first step, the excess portion in the molten state that has protruded, is pressed from at least one of the outside or the inside of the side plate, fills the gap portion of the boundary line as a filling portion, and a second step of forming a ridge-shaped closed portion. , A sufficient amount of resin to fill the gap of the boundary line is secured by the surplus portion, and the filling portion formed by filling the gap is integrated. Formation can be, by ridged closing portion having the filling section, it is possible to ensure the liquid tightness.

  In a method for manufacturing a packaging container for joining by heating and melting mutual end faces of adjacent side plates of a low-foam synthetic resin or a non-foam synthetic resin sheet including a bottom plate and each side plate integrally formed on a periphery of the bottom plate, The synthetic resin sheet is a low-foam synthetic resin sheet or a non-foam synthetic resin sheet having an expansion ratio of 8 times or less, and has a sleeve portion at a side end portion of one adjacent side plate and a side end of another adjacent side plate. A portion provided with a joining end portion that can be welded to the sleeve portion, a sheet having a V-shaped first notch formed over the sleeve portion and the joining end, and a plurality of first notches Of the two first notches having the V-shaped tip in the same direction, the first notch is heated and melted at a first virtual line passing through a position closer to the center than the two V-shaped tips, The side plate including the notch, the sleeve, and the joint end are raised. Secure a surplus part that is not in a molten state below the first notch, and heat and melt in a second virtual line passing through the first notch at two points orthogonal to the first virtual line, and opposed to each other. A first step of welding the sleeve piece portion and the joint end portion, and causing the melted surplus portion to protrude at least outside or inside the side plate, and the protruding surplus portion in the molten state to at least the outside of the side plate. Or pressing from one of the inside, filling the gap portion of the boundary line as a filling portion, and a second step of forming a ridge-shaped closed portion, because the method for manufacturing a packaging container characterized by comprising According to the V-shape of the first cutout portion formed in advance in the synthetic resin sheet, a necessary and sufficient amount of resin for filling the gap portion of the boundary line with the surplus portion is secured, and the hot plate is abutted. Surplus melted by The efficiency well formed, a filling portion formed by filling a gap portion can be formed integrally by ridged closing portion having the filling section, it is possible to ensure the liquid tightness. Further, at this time, since the amount of resin necessary and sufficient to fill the gap portion of the boundary line with the surplus portion is obtained, it is possible to shorten the time and improve the productivity. In addition, the V-shaped first notch guides the tip of the hot plate, thereby ensuring dimensional accuracy and realizing stable weldability.

It is a perspective view of the packaging container concerning Example 1 of the present invention. It is a development view of the packaging container concerning Example 1 of the present invention. It is a perspective view showing the state where a hot plate is pressed against the 1st virtual line of the low foam synthetic resin sheet which constitutes the packaging container concerning Example 1 of the present invention. FIG. 1A is a perspective view showing a state in which a front side plate and a rear side plate are erected, and FIG. 2B is a view showing a surplus portion in a low-foam synthetic resin sheet constituting a packaging container according to Example 1 of the present invention. It is a part enlarged explanatory view. Explanatory drawing showing a state in which a hot plate is pressed against a first cutout in a low-foam synthetic resin sheet constituting a packaging container according to a first embodiment of the present invention. It is a perspective view which shows the low foam synthetic resin sheet which has a 1st notch part in which the surplus part became the molten state. It is a simplified diagram showing the process of forming the closed part in the packaging container according to the first embodiment of the present invention, (a) a simplified diagram showing the relationship between the unheated state of the sleeve and the joining end, (b) melting Simplified view showing the relationship between the sleeve portion and the joining end in the state, (c) Simplified view showing the state in which the sleeve portion and the joining end in the molten state are in contact with each other and a gap is formed. (D) Simplified view showing a state in which a surplus portion is buried in a gap portion and a filling portion is formed, and (e) A simplified diagram showing a state in which a surplus portion is buried only in a gap portion on one side and a filling portion is formed. FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is the perspective view of the packaging container which made the form which attached the reinforcement frame part and the reinforcement corner part about the packaging container which concerns on Example 1 of this invention. It is a development view of the low foam synthetic resin sheet which constitutes the container body in the packaging container according to Example 2 of the present invention. It is explanatory drawing which shows (a) the 2nd side plate part of one form, and (b) the 2nd side plate part of another form in the packaging container which concerns on Example 2 of this invention. It is a perspective view which shows the state which presses a hot plate with respect to the 1st virtual line of the low foam synthetic resin sheet which comprises the container for packaging which concerns on Example 2 of this invention. It is a perspective view which shows the assembly state of the container main body in the packaging container which concerns on Example 2 of this invention, Comprising: The 1st right side board, the 1st left side board, each sleeve piece part, It is a perspective view which shows the state before forming a thermal ruled line in a 2nd virtual line by the said hot plate after standing up by using and using heat bending. It is a perspective view which shows the assembly state of the container main body in the packaging container which concerns on Example 2 of this invention, Comprising: It is a perspective view which shows the state which forms a thermal ruled line in a 2nd virtual line by a hot plate. It is a perspective view which shows the assembled state of the container main body in the packaging container which concerns on Example 2 of this invention, Comprising: The perspective view which shows the state in which the surplus part was in the molten state by the press of a hot plate, and shows the state. It is. FIG. 14 is a perspective view showing a state in which the front side plate is erected in the state of FIG. 13, the sleeve pieces and the joining ends are welded, and a closed portion is formed. FIG. 15 is a perspective view showing a state in which the rear plate is erected in the state of FIG. 14, the sleeve pieces and the joining ends are welded to each other, and a closed portion is formed. It is (a) perspective view (b) front view (c) right side view (d) bottom view which shows the reinforcement corner attached to the packaging container which concerns on the present Example 2. It is a perspective view which shows the state which attaches a 2nd side plate (2nd right side plate and 2nd left side plate) with respect to a container main body. It is a perspective view of the container for packaging concerning Example 2 of the present invention.

  Hereinafter, each embodiment of the present invention will be described in detail. It should be noted that the present invention is not limited to the following embodiments, and various design changes, addition of known techniques, and the like can be made without departing from the technical idea of the present invention.

  As shown in FIG. 1, the packaging container 1 according to the first embodiment of the present invention is mainly used for transportation, and can be used as a liquid-tight tray or the like.

  As shown in FIGS. 2 and 3, the packaging container 1 according to the first embodiment is mainly composed of one low-foam synthetic resin sheet. The low-foam synthetic resin sheet has a bottom plate 2, and a front plate 3, a rear plate 4, a right plate 5, and a left plate 6 that are respectively continuous with the bottom plate 2.

  Adjacent side plates have sleeve portions 5A, 6A or corresponding joining ends 3A, 4A. Specifically, the right side plate 5 and the left side plate 6 facing each other have the sleeve portions 5A and 6A continuously from the upper end to the lower end at each end. Further, the front side plate 3 and the rear side plate 4 facing each other have joining ends 3A, 4A at both ends thereof for welding to the sleeves 5A, 6A.

  The sleeve portion 5A has an inclined surface 50 inclined from a base end side at an end surface thereof and a vertical surface 51 continuous with the inclined surface 50. The sleeve portion 6A has an inclined surface 60 inclined from a base end side at an end surface thereof and a vertical surface 61 continuous with the inclined surface 60.

  The joint end portion 3A has an inclined surface 30 inclined from a base end side at an end surface thereof and a vertical surface 31 continuous with the inclined surface 30. The joining end 4A has an inclined surface 40 inclined from the base end side at an end surface thereof and a vertical surface 41 continuous with the inclined surface 40. The angle between the adjacent inclined surfaces of the joint ends 3A, 4A and the sleeve pieces 5A, 6A in the unfolded state is approximately 90 °.

  Also, as shown in FIGS. 2, 3 and 4 (b), the inner and outer surfaces along the inclined surfaces 50, 60 and the vertical surfaces 51, 61 of the joint ends 3A, 4A and the sleeves 5A, 6A. Is the surplus part 70.

The sleeve pieces 5A, 6A and the joining ends 3A, 4A are joined in a state where liquid tightness is secured by welding.
That is, the excess portion 70a is in a molten state with respect to the gap 8 generated in the boundary line on the inner surface side, the outer surface side, and the upper end surface of the side plate (the front side plate 3 and the rear side plate 4) where the boundary line appears as the joining portion. By embedding as the filling portion 71, the ridge-shaped closing portion 7 in which the boundary line is closed in a liquid-tight manner is formed. In the present invention, the “melted state” of the synthetic resin is a state in which at least a part of the heated synthetic resin is melted and deformable by contact with another object, and the synthetic resin itself is washed away by melting. It is the state that is held to the extent that it does not.

The packaging container 1 according to the first embodiment can be manufactured by the following procedure.
First, four corners and other portions of a low-foam synthetic resin sheet having a square shape in plan view are cut off. In addition, a virtual line that continues in the left-right direction through a position that is closer to the center in the front-rear direction than the V-shaped tip position of the first notches 12a and 12b is referred to as a first virtual line 100. The first imaginary line 100 is an imaginary line for dividing the bottom surface 2, the front side plate 3 and the rear side plate 4, dividing the right side plate 5 and the sleeve portion 5A, and dividing the left side plate 6 and the sleeve portion 6A. It is.

As shown in FIGS. 2 and 3, the cutouts formed by cutting the four corners are areas where the side plates are separated from each other and the sleeve pieces 5A, 6A and the joint ends 3A, 4A are formed. .
By cutting off the four corners, the first cut in a V-shape to form the inclined surfaces 30, 40, 50, 60 on the lower end sides of the sleeve pieces 5A, 6A and the joint ends 3A, 4A, respectively. Notches 12a and 12b are formed.
In addition, V-shaped notches 13 (hereinafter, second notches 13) having vertices at both ends of the first virtual line 100 are formed.

  Next, as shown in FIG. 3, a long hot plate P having a V-shaped cross section and heated to a predetermined temperature is pressed against the first virtual line 100 of the low-foam synthetic resin sheet. Melts the low-foam synthetic resin sheet to form a thermal ruled line to partition the bottom plate 2, the front plate 3 and the rear plate 4, the right plate 5 and the sleeve portion 5A, and the left plate 6 and the sleeve plate Section 6A is defined. The predetermined temperature of the long heat plate P can be a temperature that is equal to or higher than the melting point of the material and does not cause discoloration or decomposition of the material. For example, when the material of the low-foam synthetic resin sheet is polypropylene, the temperature can be 170 ° C or higher, and when the material is polyethylene, the temperature can be 120 ° C to 130 ° C or higher.

  Here, when the hot plate P is pressed against the first virtual line 100 of the low-foam synthetic resin sheet, the first virtual line 100 itself is not formed at all. By arranging the tip p1 having a V-shaped cross section in accordance with the two second notches 13 shown in FIGS. 2 and 3, the tip p1 can be positioned on the first virtual line 100.

While the hot crease formed by the lowering of the hot plate P is in a molten state, the side plate is raised from the bottom plate 2 based on the hot crease. At this time, in addition to the front side plate 3 or the rear side plate 4, the sleeve portions 5A and 6A at both ends of each side plate are also erected (see FIG. 4A).
The front plate 3, the rear plate 4, and the sleeve pieces 5A and 6A are welded to the bottom plate 2 in an upright state, respectively, and then naturally cooled and fixed.

  As a result of this series of operations, the first cutouts 12a and 12b formed by the initial four corner cuts are, as shown in FIG. 4, the lower ends of the sleeve pieces 5A and 6A and the lower ends of the joint ends 3A and 4A. A V-shaped groove that opens upward as a part.

  Next, the bottom plate 2 and the left side plate 6 or the right side plate 5 are partitioned. For the section, a hot plate P including a V-shaped cross section is used. A hot plate P is arranged on a second virtual line 101 passing between the V-shaped grooves to form a thermal ruled line L (see FIG. 5B).

With the formation of the thermal ruled line L, not only the thermal ruled line L, but also the V-shaped groove and the end faces of the sleeve pieces 5A and 6A and the end faces of the joining ends 3A and 4A which are connected to the V-shaped groove are in a molten state.
In a state where the formed thermal ruled line L is heated and melted, the left side plate 6 or the right side plate 5 (including these sleeve portions 5A, 6A) is erected on the basis of the thermal ruled line L, and the sleeve portion is formed. Each end face of 5A, 6A and each end face of joining ends 3A, 4A are pressed and fixed.

  Here, the first virtual line 100 is continuous in the left-right direction through a position that is closer to the center in the front-rear direction than the V-shaped tip position in the first notches 12a, 12b, As shown in FIG. 4 (b), the surplus portion 70 has a portion along the V-shape in the first notches 12a and 12b, and a tip position of the V-shape and the first imaginary line 100 continuing therefrom. And the excess resin melted from the surplus portion 70 in the welding of the sleeve pieces 5A, 6A and the joining ends 3A, 4A in the portion between the joining ends 3A, 4A. Occurs.

  Since each side plate is formed of a low-foam synthetic resin sheet instead of plastic cardboard, the molten surplus portion 70a cannot enter the low-foam synthetic resin sheet, and the sleeve pieces 5A, 6A It swells from the boundary line with the joining ends 3A, 4A (see FIGS. 5, 6 (a) to 6 (d)).

  Subsequently, before the resin of the swelled surplus portion 70a is cooled, the resin of the swelled surplus portion 70a is pressed from inside and outside of the front side plate 3 and the rear side plate 4 by any pressing means, and The swelled resin is buried as a filling portion 71 into a gap partly formed therein to be integrated, and a ridge-shaped closing portion 7 continuous with the inside, outside, and upper end of the front side plate 3 and the rear side plate 4 is formed. Form. By the formation of the closing portion 7, the packaging container 1 according to the first embodiment is completed (see FIG. 1).

Since the surface of the closing portion 7 is pressed and has a shape in which the volume h2 is suppressed as shown in FIG. 6D, it is possible to prevent other objects from being accidentally hooked on the closing portion 7.
In addition, the appearance can be improved. In addition, the strength of the resin can be improved by increasing the density of the resin at the boundary line with the formation of the closing portion 7.

In addition, as shown in FIG. 7, a known reinforcing frame portion R1 and a reinforcing corner portion R2 can be attached to the upper portion of the packaging container 1 according to the first embodiment to improve the strength of the packaging container 1. .
Furthermore, stable stacking (stacking) can be performed even during transportation and storage.

Next, a packaging container 1 (see FIG. 18) according to a second embodiment of the present invention will be described.
Incidentally, in order to form a liquid-tight structure using the main ridge-shaped closing portion 7 of the present invention, which is also common to the first embodiment, for a bulky box, a large-sized box corresponding to the length of the melting point is required. A hot plate is required. For this reason, the present invention also includes a packaging container 1 formed in a bulky manner by using a large-sized hot plate in order to make the packaging container 1 disclosed in the first embodiment bulky, and a manufacturing method thereof. However, on the other hand, the structure of the packaging container 1 according to the second embodiment described below and the manufacturing method thereof use a relatively small hot plate P common to the first embodiment and a liquid tight common to the first embodiment. In addition to having a sex configuration, the accommodation capacity can be greatly improved. As a result, according to the packaging container 1 and the manufacturing method thereof according to the second embodiment described below, the bulky packaging container 1 does not use a large hot plate, and has a liquid-tight structure similar to that of the first embodiment. In addition, there is an advantage that the manufacturing method can be realized and the manufacturing cost and the cost can be reduced while securing the storage amount.

As shown in FIGS. 8 and 9A, the packaging container 1 according to the second embodiment is configured such that the container body 10 is made of a low-foam synthetic resin sheet, and forms part of a pair of opposed side plates. The second side plate portion 11 (the second right side plate 11a and the second left side plate 11b) is formed of a hollow plastic corrugated cardboard separately from the container body 10, and is configured by combining these.
FIG. 9B shows a variation of the second side plate portion 11 used for folding in two, which has a higher buckling strength. In addition, by making the hollow plastic cardboard plate into a two-fold structure, it is possible to prevent water from entering into the hollow plastic cardboard plate from the folded portion, and to rise (water rising in the hollow plastic cardboard plate due to the capillary phenomenon). Can be prevented.

  The bottom 1a (see FIGS. 15 and 18) extending from the bottom plate 2 to a height of approximately 5 cm to 6 cm has a liquid-tight structure substantially similar to that of the first embodiment. That is, it has a bottom plate 2 and respective side plates of a front side plate 3, a rear side plate 4, a first right side plate 55, and a first left side plate 65 which are respectively continuous with the bottom plate 2, and the first right side plate 55 and the first The left side plate 65 is provided with the sleeve portions 5A and 6A continuously at both ends thereof. The sleeve pieces 5A and 6A are formed from the lower end to the upper end of the first right side plate 55 or the first left side plate 65 (see FIG. 13).

The front side plate 3 and the rear side plate 4 facing each other are provided with joint ends 5B, 6B at both ends for welding to the sleeves 5A, 6A.
The sleeve pieces 5A, 6A and the joining ends 5B, 6B are joined by welding. The inner side, the outer side, and the upper end of the side plates (the front side plate 3 and the rear side plate 4) where the boundary line appears as the joining portion are filled with resin for the slight gap portions 8 formed in the boundary line. A ridge-shaped closing portion 7 which is embedded and integrated as 71 and closes the gap 8 is provided.

And in the central part 1b which continues above the said bottom part 1a, about the front side surface and the back side surface side, the front side plate 3 and the rear side plate 4 are each extended continuously upward from the bottom part 1a, respectively, and are about 30 cm. The height is secured. On the other hand, on the right side surface and the left side surface side, there is provided a side support piece portion 14 which is continuous from the side ends of the front side plate 3 and the rear side plate 4 and abuts on the upper end of the first right side plate 55 or the first left side plate 65. ing. The inner side surfaces of the two side support portions 14 on the right side surface are fixed to the outer side surface of the second right side plate 11a.
The inner side surfaces of the two side support pieces 14 on the left side are fixed to the outer side of the second left side plate 11b.
Further, the inner side surface of the first right side plate 55 and the outer side surface of the second right side plate 11a in the bottom portion 1a, the inner side surface of the first left side plate 65 and the outer side surface of the second left side plate 11b are in contact with each other.

The packaging container 1 according to the second embodiment can be manufactured by the following procedure (see FIGS. 8 to 17).
In the packaging container 1 according to the first embodiment, the bottom plate 2 and the front, rear, left and right side plates 5 and 6 are integrally obtained from one low-foam synthetic resin sheet. In the packaging container 1, the bottom plate 2, the bulky front side plate 3 and the rear side plate 4, the low bulky first right side plate 55 and the first left side plate 65, each side support piece are formed from the single low-foam synthetic resin sheet. The part 14 and the respective sleeve pieces 5A and 6A are obtained, and the bulky second right side plate 11a and second left side plate 11b which are bulky as shown in the packaging container 1 according to the second embodiment are separately formed.

First, as shown in FIG. 8, a side support portion 14, sleeve portions 5A and 6A, a first right side plate 55, a first left side plate are formed at four corners and the like of a low-foam synthetic resin sheet having a square shape in plan view. Unnecessary portions are cut out to form 65.
In this state, virtual lines (first virtual line 100, second virtual line 101) in the figure are not formed as ruled lines.

In FIG. 8, a rear plate 4 is provided continuously at the upper end of the bottom plate 2 located at the center. A front plate 3 is provided continuously at the lower end of the bottom plate 2. A first right side plate 55 is provided continuously to the right end of the bottom plate 2. A first left side plate 65 is provided continuously to the left end of the side plate.
Further, the right and left ends of the front plate 3 and the rear plate 4 have a side support portion 14 and sleeve portions 5A and 6A. The sleeve pieces 5A and 6A are disposed closer to the bottom plate 2 than the side support pieces 14 and are continuous with the first right side plate 55 or the first left side plate 65.

The first cut into a V-shape is provided at a position where the first right side plate 55 and the sleeve portion 5A are continuous, and at a position where the first left side plate 65 and the sleeve portion 6A are continuous. The notches 12a and 12b are formed.
In addition, a linear cut 15 is provided at the boundary between each side support portion 14 and the sleeve portions 5A and 6A.
The leading end position of the cut 15 is closer to the center in the width direction of the low-foam synthetic resin sheet than the V-shaped leading end positions of the first notches 12a and 12b. Thus, when a virtual line passing through the tip positions 150 of the cuts 15 is formed, the surplus portion 70 can be secured adjacent to the V-shaped tip position 150 of the first all-missing portion.

  Also, at the upper end positions of the front side plate 3 and the rear side plate 4, a third cutout portion 107 for attaching a reinforcing corner portion R2 and an extension portion for attaching a first tongue piece portion 109 and a reinforcing frame portion R1. 103 is formed. A cut line 102 is provided as a base end of the extension portion 103 (that is, a boundary line between the front side plate 3 and the rear side plate 4). The cut line 102 is formed as a shallow cut (generally a depth of less than half the thickness of the low foaming synthetic resin sheet and a depth at which the low foaming resin sheet can be folded back). . By setting the cut at the depth, accidental cutting due to the formation of the cut line 102 is prevented, and the rebound resilience after bending is ensured.

  Next, similarly to the first embodiment, the material is heated to a predetermined temperature (that is, a temperature at which the material can be processed at a temperature higher than the melting point of the material and not causing discoloration or decomposition of the material). By pressing the formed long heat plate against the first virtual line 100 which partitions the left and right side support pieces 14 and the sleeve pieces 5A and 6A in the low foam synthetic resin sheet, the low foam foam is obtained. The synthetic resin sheet is melted to form a thermal crease. The first virtual line 100 may be a line connecting the tip positions 150 of the cuts 15.

  By setting the first virtual line 100, a certain distance is maintained between the first virtual line 100 and the V-shaped tip positions of the first notches 12a and 12b. Thus, the surplus portion 70 is secured.

  In a state where the formed thermal ruled line is melted, the first right side plate 55, the first left side plate 65, and the sleeve pieces 5A, 6A are raised from the bottom plate 2, the front side plate 3 and the rear side plate 4 based on the thermal ruled line. Then, it is fixed to the bottom plate 2, the front side plate 3 and the rear side plate 4.

  Then, it is naturally cooled and fixed in this state. As a result of this series of operations, the first cutouts 12a and 12b become V-shaped grooves that open upward at the lower end positions of the sleeve pieces 5A and 6A and the lower end positions of the joining ends, as shown in FIG.

Next, as shown in FIGS. 12 and 13, the long hot plate heated to a predetermined temperature is pressed against the second virtual line 101 in the low-foam synthetic resin sheet, thereby The thermal crease is formed by melting the foamed resin sheet.
The second virtual line 101 can be a line connecting the V-shaped grooves formed by the first notches 12a and 12b.

With the formation of the thermal ruled line, the respective end surfaces (inclined surfaces 50, 60 and vertical surfaces 51, 61) of the sleeve pieces 5A, 6A, and the respective joint ends of the first right side plate 55 and the first left side plate 65. The end surfaces of 5B and 6B (inclined surfaces 550 and 650 and vertical surfaces 551 and 651) are in a molten state.
In a state where the formed thermal creases are melted, as shown in FIG. 14, the front side plate 3 and the rear side plate 4 (including these sleeve portions 5A and 6A) are erected on the basis of the thermal creases, and as shown in FIG. Each end surface (each inclined surface 50, 60 and vertical surface 51, 61) of the sleeve pieces 5A, 6A and each said joint end portion 5B, 6B (particularly, each inclined surface) of the first right side plate 55 and the first left side plate 65 550, 650 and the vertical surfaces 551, 651) are pressed and fixed.

  In the second embodiment, since a fixed distance is maintained between the first imaginary line 100 and the V-shaped tip positions of the first notches 12a and 12b, the surplus portion 70 which is not in the molten state is maintained. In the welding of the sleeve pieces 5A, 6A to the respective joining ends 5B, 6B of the first right side plate 55 and the first left side plate 65, an excessive resin melt is generated. (See FIG. 6. Here, in the second embodiment, the reference numeral 3A is replaced with 5B when referring to FIG. 6.)

  Also in the second embodiment, since each side plate is formed of a low-foam synthetic resin sheet, the melted surplus portion 70a cannot enter the low-foam synthetic resin sheet, and the sleeve pieces 5A, 6A And bulges from the boundary line between the joint ends 5B and 6B.

  Subsequently, while the swollen resin is not cooled, the swollen resin portions are pressed from inside and outside of each of the sleeve pieces 5A and 6A and the first right side plate 55 and the first left side plate 65 by pressing means. The swelled resin is embedded and integrated into the gap 8 formed in a part of the boundary line, and is connected to the boundary line between the first right side plate 55 or the first left side plate 65 and each of the sleeve pieces 5A, 6A. A ridge-shaped closing portion 7 is formed. By the formation of the closing portion 7, the bottom 1a of the packaging container 1 according to the second embodiment is completed (see FIG. 15).

Next, as shown in FIG. 17, the second right side plate 11 a is brought into contact with each inner surface of the first right side plate 55, the respective sleeve pieces 5 A, and the upper side support pieces 14, and And the second right side plate 11a. Further, the second left side surface 11b is brought into contact with each inner surface of the first left side plate 65, the respective sleeve pieces 6A, and the upper side support pieces 14 thereabove, and the side support pieces 14 and the second left side plate 11b are fixed. I do.
As the fixing method, any conventionally known fixing method such as bonding using ultrasonic waves and heat welding can be used.

  The second right side plate 11a and the second left side plate 11b in the second embodiment have a common shape and are made of plastic cardboard. The plastic cardboard is constituted by two opposing constituent plates 110 and a plurality of ribs 111 provided in parallel at predetermined intervals between the constituent plates 110. A space 111a is provided between the plurality of ribs 111 (see FIG. 17).

In the second right side plate 11a and the second left side plate 11b according to the second embodiment, the longitudinal direction of the rib 111 is the vertical direction. The upper portion has a fourth notch 113 for attaching the reinforcing corner R2, an extended portion 105 for attaching the second tongue piece 114, and the reinforcing frame R1. A cut line 104 is provided at the base end of the extension portion 105. The cut line 104 is formed as a shallow cut (approximately a depth that allows the plastic cardboard to be folded back).
A handle hole 106 is provided on the upper side.

The method of fixing the second right side plate 11a and the second left side plate 11b in the second embodiment is based on heat welding.
With this configuration, the liquid tightness is maintained at the height from the bottom surface to the upper ends of the sleeve portions 5A and 6A by the ridge-shaped closing portion 7 that closes the boundary line, as in the first embodiment.
Then, after the liquid tightness is ensured, a storage amount is secured at a height exceeding the height.

After the second right side plate 11a and the second left side plate 11b are fixed to the side support pieces 14, the reinforcing corners R2 are attached to the four upper corners.
The reinforcing corner portion R2 according to the second embodiment has a tongue piece holding portion R22 that opens below the main body portion R20, and the first tongue piece portion 109 at the upper end of the front side plate 3 or the rear side plate 4 and the tongue piece portion R22. The second tongue piece 114 at the upper end of the second right side plate 11a or the second left side plate 11b is held together, and a connection portion R21 capable of attaching the reinforcing frame portion R1 is provided at both ends. . The connection portion is fitted into the third cutout portion 107 and the fourth cutout portion 113, and the upper end of the front side plate 3 or the rear side plate 4 and the upper end of the second right side plate 11a or the second left side plate 11b. Holding allows positioning (see FIGS. 16 and 17).

  After the reinforcing corners R2 are attached to the upper four corners, the reinforcing frame R1 is attached to each edge of the second right side plate 11a, the second left side plate 11b, the front side plate 3, and the rear side plate 4. The reinforcing frame portion R1 has a holding portion R10 having a substantially U-shaped cross section, and a locking claw R11 is provided on an inner surface of the holding portion R10. The extended portions 103, 105 at the upper ends of the second right side plate 11a, the second left side plate 11b, the front side plate 3, and the rear side plate 4 are respectively positioned inside with reference to the cutting lines 102, 104 as shown by the arrow s. In the bent state, the reinforcing frame portion R1 was attached with the opening having a U-shaped cross section downward, and the end portions of the bent extended portions 103 and 105 were engaged with the engaging claws R11. State. Further, both ends of the reinforcing corner portion R2 are held by the reinforcing frame portion R1, and the reinforcing corner portion R2 cannot be detached from the packaging container 1 together with the reinforcing frame portion R1, and the strength of the upper end portion is secured (FIGS. 16 to 16). 18).

Although the handle hole 106 is provided in the second embodiment, the handle hole 106 may be used as it is, or a handle (not shown) may be separately attached.
The handle to be attached may be open to facilitate gripping, or may be closed at the top of the packaging container 1.

  Further, in the cutting line 102 formed in the extension portion 103 disclosed in the second embodiment, a shallow cut is used. However, the present invention is not limited to the cut, and the present invention is not limited to the cut. As long as prevention, easiness of bending and rebound resilience after bending can be ensured, other ruled lines such as a press ruled line and a lead ruled line can be used.

  In the second embodiment, the inner surface of the first right plate 55 and the outer surface of the second right plate 11a, the inner surface of the first left plate 65, and the outer surface of the second left plate 11b abut on the bottom 1a. Although the present invention is not limited to the configuration of the second embodiment, the present invention is not limited to the configuration of the inner side surface of the first right side plate 55, the outer side surface of the second right side plate 11a, and the first left side plate 65. The side surface and the outer side surface of the second left side plate 11b may be configured to be fixed using ultrasonic welding or the like.

In the second embodiment, the second right side plate 11a and the second left side plate 11b are configured to use plastic cardboard. However, the present invention is not limited to the above configuration.
For example, if the strength is not excessively required in a packaging container for use in a lightweight container, a low-foam synthetic resin sheet or a non-foam synthetic resin sheet, for example, should be used. Can also.
Further, the plastic cardboard is not limited to the one having the parallel rib shown in the second embodiment.
For example, two polypropylene plastic sheets with truncated cones arranged in a staggered grid are welded together at the ends of pins, and then a four-layer plastic sheet with a face plate attached to the surface (trade name "Twin cone") (Registered trademark)) and various known plastic cardboards.

  Further, the second right side plate 11a and the second left side plate 11b may be provided with a bent portion 112 that is continuous in the width direction at the center in the longitudinal direction as shown in FIG. it can. According to this configuration, the strength can be further improved, and the intrusion of the liquid into the hollow plastic cardboard can be suppressed.

Further, the ridge-shaped closing portion 7 of the present invention only needs to fill and close the gap along the boundary line, and the shape such as unevenness of the outer shape and presence or absence of a flat surface is not particularly limited. For example, two narrow ridges may be arranged side by side, or one wide ridge may be used. The ridge shape of the present invention does not indicate only a so-called ridge shape, but may be a shape that continuously covers the entire boundary line.
In the above-described embodiment, the configuration in which the closing process is performed from both the inside and the outside as shown in FIG. 6D is described. However, according to the present invention, the closing process is performed from only one of the inside and the outside. May be performed.

  On the other hand, the smaller the volume of the closed portion 7 from the boundary line is, the smaller the possibility of contact with other objects is, which is more preferable. In addition, it is more preferable that the closed portion 7 does not protrude to the bottom surface side so that the horizontal position at the time of mounting is maintained and the stability can be secured.

In the process of the method for manufacturing the packaging container 1 of the present invention, in the second step of forming the ridge-shaped closed portion 7, the pressing operation for filling the gap 8 of the boundary line uses a control device. The pressing may be performed by pressing means, or the processing may be performed manually by an operator using a jig or other object having heat resistance.
Further, the forming process of the filling portion 71 in the closing portion 7 is not limited to the process performed from both the outside and the inside shown in the embodiment, and the process of performing the filling process from only one of the outside and the inside may be used. Including.

The packaging container 1 of the present invention discloses a low-foam synthetic resin sheet in the above-described embodiment. Specifically, for example, foamed polypropylene, foamed polyethylene, or the like may be used as a suitable low-foamed synthetic resin sheet. it can. Further, a non-foamed synthetic resin sheet may be used.
In the case of a low-foam synthetic resin sheet, the expansion ratio may be approximately 8 times or less, and more preferably 1.3 to 5 times the foam. If the expansion ratio exceeds 8 times, there is a problem in the strength of the packaging container 1 and the possibility of breakage increases, which is not preferable.

  As described above, the liquid-tight structure in the present invention is basically made of a packaging container made of a non-foamed synthetic resin sheet or a low-foamed synthetic resin sheet, and is not made of hollow plastic cardboard.

Further, according to the present invention, by providing the position of the virtual line as in the case of the second cutout 13 in the first embodiment, the thermal ruled line (thermal V ruled line) formed in conformity with the virtual line can be eliminated. When the foamed synthetic resin sheet or the low-foamed synthetic resin sheet is folded, the cutout portion 13 can prevent the resin material in the folded portion from forming an outwardly projecting portion.
Thereby, in addition to the appearance appearance being improved, when performing the positioning of the mounting position during the assembling work, it is possible to prevent the positioning of the mounting position caused by the protrusions from being hindered, and to more smoothly. Assembly work can be performed.

DESCRIPTION OF SYMBOLS 1 Packaging container 1a Bottom part 1b Central part 10 Container main body 100 1st virtual line 101 2nd virtual line 102 Cut line 103 Extension part 104 Cut line 105 Extension part 106 Handle hole 107 Third cut part 109 1st tongue piece 11 2nd side board (2nd right side board and 2nd left side board)
11a second right side plate 11b second left side plate 110 constituent plate 111 rib 111a space portion 112 bent portion 113 fourth notch portion 114 second tongue piece 12a first notch portion (V-shaped notch portion, front plate side) )
12b First cutout (V-shaped cutout, rear plate side)
Reference Signs List 13 second cutout 14 side support piece 15 cut 15 tip position 2 bottom plate 3 front plate 30 inclined surface 31 vertical surface 3A joining end (Example 1)
4 Rear plate 40 Inclined surface 41 Vertical surface 4A Joining end (Example 1)
5 Right side plate 50 Inclined surface 51 Vertical surface 55 First right side plate 550 Inclined surface (Example 2)
551 Vertical surface (Example 2)
5A Sleeve piece 5B Joining end (Example 2)
6 Left side plate 60 Inclined surface 61 Vertical surface 65 First left side plate 650 Inclined surface (Example 2)
651 Vertical surface (Example 2)
6A Sleeve piece 6B Joining end (Example 2)
7 Closed part 70 Surplus part (70a surplus part (molten state))
71 Filling portion 8 Gap L Heat crease P Heat plate p1 Tip s Arrow R1 Reinforcement frame R10 Holder R11 Locking claw R2 Reinforcement corner R20 Main body R21 Connection R22 Tongue holder h2 Bulk

Claims (5)

A bottom plate made of non-foamed or low-foamed synthetic resin and side plates integrally formed on the periphery of the bottom plate are provided. The side container of the side plate has a joining end portion that can contact with the sleeve portion, in a packaging container having a gap at a boundary line where the sleeve portion and the joining end portion of each side plate abut,
The bottom plate and each side plate are non-foamed or a low foaming synthetic resin having an expansion ratio of 8 or less,
One side plate having a joint end portion of each side plate is a front side plate located at the front, and a side plate facing the front side plate is a rear side plate located at the rear,
The right side plate is located on the right side when viewed from the front side to the rear side, and the left side plate is located on the left side when viewed from the front side to the rear side,
The sleeve portion has an inclined surface inclined from a base end side at an end surface thereof and a vertical surface continuous with the inclined surface,
The joining end has another inclined surface inclined from the base end side at the end surface thereof and another vertical surface continuous with the other inclined surface,
Constituting a first notch formed in advance by the inclined surface of the sleeve portion and the other inclined surface of the joining end portion,
Left in the front side plate, in the first cutout on the right side, a line passing through the rear position from the tip where the inclined surface and the other inclined surface are connected, and left and right first in the rear side plate In the notch, a line passing through a position ahead of the tip where the inclined surface and the other inclined surface are connected, each as a first virtual line,
Comprising a surplus portion which is previously formed at a position between the first notch portion of the near portion and the first notch and the first imaginary line, the surplus portion is melted, and the sleeve piece At least one of the outer surface side or the inner surface side of the boundary line by fusion-bonding the joining end portion, having a filling portion in which the molten excess portion is filled in the gap portion, a ridge-shaped closing portion A packaging container characterized by being formed.   The pair of opposing side plates includes the sleeve portion on the lower side of both ends thereof, and includes a side support portion that is continuous from an upper position of the sleeve portion to an adjacent side surface. The packaging container according to claim 1, further comprising a second side plate fixed to an inner surface of the side support portion.   3. The packaging according to claim 2, wherein the second side plate is made of a plastic cardboard having a plurality of parallel ribs between two component plates, and a longitudinal direction of the ribs is arranged in a vertical direction. Container.   The packaging container according to claim 1, further comprising a reinforcing frame portion and a reinforcing corner portion for reinforcing an upper end portion. In a method for manufacturing a packaging container for joining by heating and melting mutual end faces of adjacent side plates of a low-foam synthetic resin or a non-foam synthetic resin sheet including a bottom plate and each side plate integrally formed on a periphery of the bottom plate,
The synthetic resin sheet is a low foam synthetic resin or a non-foam synthetic resin sheet having an expansion ratio of 8 or less,
A side end of one of the side plates adjacent to each other is provided with a sleeve end, and a side end of the other side plate adjacent to the side is provided with a joining end that can contact the sleeve end.
The sleeve portion has an inclined surface inclined from a base end side at an end surface thereof and a vertical surface continuous with the inclined surface,
The joining end has another inclined surface inclined from the base end side at the end surface thereof and another vertical surface continuous with the other inclined surface,
The inclined surface of the sleeve portion and the other inclined surface of the joining end portion constitute a first notch formed in advance,
With respect to two first notches having a V-shaped tip in the same direction among a plurality of first notches, a line passing through a position closer to the center than the two V-shaped tips is a first virtual line. age,
A sheet provided with a surplus portion that is formed in advance at a position between the first cutout portion and a position between the first cutout portion and the first virtual line,
The first virtual line is heated and melted, and the side plate including the first notch portion and the surplus portion which is not in a molten state, the sleeve portion and the joining end are erected, and the lower portion is below the first notch portion. Between the adjacent portion of the first notch and the first imaginary line located below the first notch, the previous step of securing the surplus portion that is not in a molten state,
The first notch and the excess portion are orthogonal to the first imaginary line in the sheet on which the surplus portion is formed, and are heated and melted in a second imaginary line passing through two opposing first notches. The first step of welding the sleeve portion and the joining end portion, and causing the melted surplus portion to protrude at least outside or inside the side plate,
A second step of pressing the excess portion in the molten state that protrudes from at least one of the outside and the inside of the side plate, filling the gap portion of the boundary line as a filling portion, and forming a ridge-shaped closed portion. A method for producing a packaging container, comprising:

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