JP2012051611A - Synthetic resin-made cup container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain weight reduction of a container without decreasing impact resistance of the container by avoiding the decrease in impact resistance by thinning of the wall structure part of the cup container.SOLUTION: In the cup container made of a synthetic resin having a flange 4 peripherally provided in an outer flange-like shape on the opening end of the upper part by injection molding, the cup container is divided into a load-resistant bottom side part 7 of the lower site and a weight reduction cylindrical wall part 8 of the upper site, and the wall thickness of the wall structure part of a cylindrical wall 1 constituting the weight reduction cylindrical wall part 8 is made thinner than the wall thickness of the wall structure part of the load-resistant bottom side part 7, and the wall thickness is gradually decreased as going to the upper site to obtain safely and surely the weight reduction.

Description

  The present invention relates to a cup container made of synthetic resin by injection molding, which is configured for the purpose of weight reduction.

  In recent years, many cups made of synthetic resin by injection molding have been used as container bodies for beverage containers. For example, as described in Patent Document 1, a mold for molding a cup container by this type of injection molding has a structure in which a molten resin is injected from the center of the bottom of the cup container. The flange is filled through the bottom wall and the cylinder wall.

JP 2000-128141 A

  In a synthetic resin cup container to be injection-molded, since a relatively low molecular weight synthetic resin can be used, the wall structure portion can be thinned. As mentioned in the drop of impact strength due to molecular orientation due to the flow of molten resin in cup containers made of polyester resin, weight reduction due to demand for resource saving and cost reduction, that is, thinning of the wall structure part is promoted And the relatively low molecular weight of the synthetic resin, combined with the effect of molecular orientation on the resin flow, due to the impact of dropping the container filled with the content liquid and buckling deformation when loading the container, There is a problem that cracks are likely to occur in the wall structure.

  That is, when the weight is reduced by reducing the wall thickness of the wall portion of the cup container, the rigid strength of the wall structure portion is reduced and the cracks are likely to occur as the thickness is reduced. In particular, when the cup container is dropped with its contents stored, or when a large number of cup containers are stacked, the lower part of this cup container is affected by the impact load acting on the lower part of the cup container. Cracks are likely to occur in the wall structure portion of.

  Therefore, the present invention was devised to solve the above-described problems in the prior art, and it is a technical problem to prevent the thinning of the wall structure portion of the cup container from reducing the impact strength. Therefore, an object is to achieve weight reduction of the container without lowering the impact strength of the container.

The main configuration of the present invention for solving the above technical problem is:
A cup container made of synthetic resin by injection molding, in which the lower end of a cylindrical wall having an outer flange-shaped flange around the upper opening end is closed with a bottom wall having leg cylinder pieces;
This cup container is a cylinder located between the load-bearing bottom side portion and the flange, and the load-bearing bottom side portion, which is the lower portion to which the load impact force when dropped or the buckling deformation force during loading acts. Partitioning it into a light-weight cylinder wall that is a wall,
Maintain the wall thickness of the wall structure of the load-bearing bottom side at a value that can withstand the load impact force when dropped and the buckling deformation force when loaded,
The wall thickness of the wall structure portion of the light-weight cylinder wall portion was gradually decreased as the wall thickness of the wall structure portion of the load bearing bottom side portion approached the flange from the load bearing bottom side portion,
It is in.

  The wall thickness of the load-bearing bottom part is maintained at a value that can withstand the load impact force when dropped and the buckling deformation force during loading, so reduce the strength of this load-bearing bottom part. There is no risk of cracking during handling with the contents stored.

  Since the weight-reduced cylindrical wall is a part where the load impact force at the time of dropping and the buckling deformation force at the time of loading hardly act, durability against these forces is rarely required. Compared to the bottom side portion, the wall thickness of the wall structure portion can be reduced.

  Therefore, it is possible to obtain a lighter weight by uniformly reducing the wall thickness of the entire wall structure part of the lighter cylinder wall part. The buckling deformation force does not necessarily act at all, and the acting force decreases as it goes up, so that the wall of the light-weighted cylindrical wall portion is adapted to adapt to the changing form of the acting force. By gradually decreasing the thickness from the load-bearing bottom side portion toward the flange, it is possible to safely and efficiently achieve the weight reduction in the lightened cylindrical wall portion. The gradual reduction of the wall thickness in the light-weighted cylindrical wall portion may be continuous or stepwise.

  In addition, this light weight cylinder wall part has its lower end connected to the load bearing bottom part and its upper end connected to the flange. Both the load bearing bottom part and the flange have high mechanical strength. The upper and lower ends of the wall portion are mechanically reinforced by the load-bearing bottom side portion and the flange.

  Another configuration of the present invention is such that, in the main configuration described above, the gradual decrease in the wall thickness of the lightened cylindrical wall portion is within a range of 93% to 56% of the wall thickness of the load-bearing bottom side portion. is there.

  If the wall thickness of the weight-reduced bottom wall portion is within the range of 93% to 56% of the wall thickness of the load-bearing bottom side portion, the weight is reduced relative to the wall thickness of the load-bearing bottom side portion. The gradually decreasing state of the wall thickness of the chemical tube wall portion can be made smooth rather than abrupt.

  In addition, another configuration of the present invention is a tapered surface-shaped inner portion that expands toward the lower end portion of the light-weighted cylindrical wall portion adjacent to the load-bearing bottom side portion as the distance from the load-bearing bottom side portion increases. A step portion having a peripheral surface is formed.

  In the case where the lower end portion of the light weight cylindrical wall portion is formed with a step portion, the lower weight portion connecting the light weight cylindrical wall portion to the load bearing bottom side portion by the step portion, and the load bearing bottom side Can be partitioned into an upper part that is remote from the part, and the wall thickness of the lower part can be increased to sufficiently withstand internal stresses transmitted from the load-bearing bottom part, The wall thickness is reduced so that a great lightening effect can be obtained. Moreover, there is no possibility that the stepped portion may deteriorate the appearance appearance of the container.

  Further, another configuration of the present invention is obtained by gradually reducing the wall thickness of the lightened cylindrical wall portion in the main configuration described above by increasing the degree of expansion of the inner diameter of the lightened cylindrical wall portion. is there.

  In the case where the wall thickness of the lightened cylindrical wall portion is gradually reduced by increasing the diameter of the lightened cylindrical wall portion, the entire outer surface of the cylindrical wall, which is the main part of the container, is removed. A simple smooth surface close to a quadratic surface can be obtained.

Since the present invention has the above-described configuration, the following effects can be obtained.
In the main configuration of the present invention, it is possible to achieve light weight safely and efficiently with a configuration that does not cause cracking when handled in the state in which the contents are stored. Can be obtained.

  If the wall thickness of the weight-reduced bottom wall portion is within the range of 93% to 56% of the wall thickness of the load-bearing bottom side portion, the weight is reduced relative to the wall thickness of the load-bearing bottom side portion. Since the gradual reduction of the wall thickness of the plasticized cylinder wall part can be made smooth rather than abrupt, the internal stress acting on a part of the lightened cylindrical wall part with the reduced wall thickness is extremely concentrated. This can be prevented, and the safety of the lighter cylindrical wall portion can be further increased.

  In the case where a step portion is formed at the lower end portion of the light-weighted cylindrical wall portion, the gradually decreasing structure of the wall thickness in the light-weighted cylindrical wall portion can provide high safety and effective wall thickness reduction. Since there is no fear that the portion deteriorates the appearance of the container, the weight can be safely reduced, and the appearance of the container can be simplified.

  In the case where the wall thickness of the lightened cylindrical wall portion is gradually reduced by increasing the diameter of the lightened cylindrical wall portion, the entire outer surface of the cylindrical wall, which is the main part of the container, is removed. Since the surface can be a simple smooth surface close to a quadratic curved surface, label sticking to the outer surface of the cylinder wall can be suitably achieved, and the ease of displaying a pattern or the like can be maintained.

It is the whole half longitudinal cross-sectional view which shows one Example of the cup container of this invention. It is a top view of the embodiment shown in FIG. It is a principal part expanded longitudinal sectional view which shows the detail of the structure relevant to a cylinder wall.

Hereinafter, it demonstrates along the Example according to this invention, referring drawings.
1 to 3 show one embodiment of a synthetic resin cup container of the present invention, FIG. 1 is a half-cut overall view, FIG. 2 is a plan view thereof, and FIG. 3 is a structure related to a cylindrical wall. It shows the details.
This cup container is an injection-molded product made of polypropylene resin, the total height is 118 mm, the diameter of the upper end portion of the cylindrical wall 1 of the conical cylindrical shape that is gradually expanded upward is 65 mm, and the diameter of the lower end portion is 51 mm. The capacity is 250 ml.

  A flange 4 is provided around the upper opening end of the cylindrical wall 1 in the form of an outer casing, and a projecting piece 2 for preventing stacking when the cup containers are stacked is provided on the inner peripheral surface of the cylindrical wall 1. A plurality of protrusions are provided at center angle intervals.

  In addition, a bottom wall 5 whose center is curved and recessed inward from the height position near the lower end of the cylindrical wall 1 is integrally connected so as to close the lower end of the cylindrical wall 1. A short cylindrical leg cylinder piece 6 that functions as a leg portion is suspended from the lower end of the wall 5 in a form in which the cylinder wall 1 is extended downward.

  The cup container 1 includes a load-bearing bottom side portion 7 (see FIGS. 1 and 3) configured by a lower portion of the cylindrical wall 1 below the projecting piece 2 and a bottom wall 5 having leg tube pieces 6. It is partitioned vertically into a light-weighted cylindrical wall portion 8 that is a cylindrical wall 1 portion up to the flange 4 continuously connected to the upper end of the load-bearing bottom side portion 7.

  The load-bearing bottom portion 7 is a portion to which a load impact force when dropped with the contents stored and a buckling deformation force when loading the container acts, and the wall structure portion of the load-bearing bottom portion 7 The wall thickness is maintained at a conventional value (generally 0.7 mm) that can withstand the load impact force during dropping and the buckling deformation force during loading. The value of the wall thickness of the wall structure portion in the load-bearing bottom portion 7 is the limit value of the current weight reduction, and the flange 4 has the same wall thickness.

  The weight-reduced cylindrical wall portion 8 is a portion for achieving weight reduction. The wall thickness of the wall structure portion is set so that the wall thickness of the load structure bottom side portion 7 is less than the load-bearing bottom side portion 7. As the distance from the distance increases, that is, as it goes upward, it is gradually reduced, and the weight is reduced by this gradually reduced wall thickness. The gradual decrease in the wall thickness of the wall structure portion in the light-weighted cylindrical wall portion 8 should be within a range of 93% to 56% with respect to the wall thickness of the load-bearing bottom side portion 7, specifically, When the wall thickness of the wall structure portion of the load bearing bottom side portion 7 is 0.7 mm, a range of 0.65 mm (92.85%) to 0.40 mm (57.14%) is suitable.

  The light weight cylindrical wall portion 8 is reinforced by connecting the lower end to the load-bearing bottom portion 7 and the upper end to the flange 4, so that the self-shape retaining force is stable for the wall thickness. Therefore, it is possible to promote the weight reduction of the wall structure portion of the lightened cylindrical wall portion 8 accordingly. Further, the upper end portion of the lightened cylindrical wall portion 8 has the smallest wall thickness of the wall structure portion, and is therefore mechanically weak. Since it is reinforced with the flange 4 having mechanically stable strength, there is almost no risk of breakage such as “cracking” due to insufficient mechanical strength.

  On the inner peripheral surface of the lower end portion of the light-weighted cylindrical wall portion 8, a step portion 3 (see FIG. 3) is formed in which the wall thickness is gradually reduced by increasing the diameter as approaching away from the load-bearing bottom side portion 7. Thus, the formation of the stepped portion 3 allows the form and degree of the gradual reduction of the wall thickness in the lightened cylindrical wall portion 8 to be freely selected and set, thereby providing a lighter weight effect on the lightened cylindrical wall portion 8. Trying to get.

  An actual measurement example of the wall thickness of the wall structure portion in the main portion of the container is shown in FIG. In FIG. 3, the wall thickness at the point 1p1 of the bottom wall 5 constituting the load bearing bottom side portion 7 and the point 2p2 of the cylindrical wall 1 portion constituting the load bearing bottom side portion 7 is 0.7 mm, respectively. The wall thickness at the point 3p3 immediately below the step portion 3 of the cylindrical wall 1 constituting the conversion tube wall portion 8 is 0.65 mm (92.85%), and the wall thickness at the point 4p4 immediately above the step portion 3 is 0. The wall thickness at the point 5p5 immediately below the flange 4 of the cylindrical wall 1 constituting the light-weighted cylindrical wall portion 8 is 52 mm (74.28%) and 0.45 mm (64.28%).

  As described above, the wall thickness of the upper end portion of the wall structure portion of the cylindrical wall 1 constituting the lightened cylindrical wall portion 8 is reduced to about half of the wall thickness of the wall structure portion of the load-bearing bottom side portion 7. However, when the lightweight cylindrical wall portion 8 is gripped and handled, the lightweight cylindrical wall portion 8 is not unstablely bent and deformed, and the gripping state of the container is stable.

  The gradual reduction of the wall thickness in the lighter weight cylindrical wall portion 8 above the stepped portion 3 is performed in a state in which the degree of expansion of the inner and outer diameters of the cylindrical wall 1 according to the upper level is kept constant. It is obtained by increasing only the diameter expansion degree. For this reason, the whole outer peripheral surface of the cylindrical wall 1 will form a simple and smooth truncated cone-shaped secondary curved surface, and a display function member such as a label can be properly attached.

  As mentioned above, although embodiment of this invention and its effect were demonstrated along the Example, this invention is not limited to this Example. In the above embodiment, the resin is made of polypropylene resin, but other synthetic resins can be selected according to the purpose of use. In addition, by providing a plurality of stepped portions 3, it is possible to select and set the degree of gradual reduction of the wall thickness in the light-weighted cylindrical wall portion 8 to a desired level.

  As described above, the synthetic resin cup container of the present invention has a wall structure that hardly requires durability strength against load impact force when dropped with the contents stored and buckling deformation force when the container is loaded. A part is used to achieve weight reduction, and it is expected to be used in a wide range of applications, especially in applications where a thinner peripheral wall is required.

DESCRIPTION OF SYMBOLS 1; Tube wall 2; Projection piece 3; Step part 4; Flange 5; Bottom wall 6; Leg tube piece 7; Load-bearing bottom side part 8;
p2; Point 2
p3; Point 3
p4; point 4
p5; point 5

Claims (4)

A synthetic resin cup by injection molding, in which the lower end of a cylindrical wall (1) having an outer flange-like flange (4) around the upper opening end is closed by a bottom wall (5) having a leg cylinder piece (6). A load-bearing bottom side portion (7) which is a lower portion to which a load impact force at the time of dropping or a buckling deformation force at the time of loading is applied, and the load-bearing bottom side portion ( The wall thickness of the wall structure portion of the load-bearing bottom side portion (7) is divided into a light-weighted cylindrical wall portion (8) that is a portion of the cylindrical wall (1) located between 7) and the flange (4). Is maintained at a value capable of withstanding the load impact force at the time of dropping and the buckling deformation force at the time of loading, and the wall thickness of the wall structure portion of the lightened cylindrical wall portion (8) is set to the load-bearing bottom. The wall thickness of the wall structure portion of the side portion (7) is gradually decreased from the load-bearing bottom side portion (7) toward the flange (4). Plastic cup container. The synthetic resin cup container according to claim 1, wherein the wall thickness of the light-weighted cylindrical wall portion (8) is gradually reduced within a range of 93% to 56% of the wall thickness of the load-bearing bottom side portion (7). A stepped portion having a tapered surface-like inner peripheral surface that increases in diameter as it is farther from the load-bearing bottom side portion (7) at the lower end portion of the light-weight cylindrical wall portion (8) adjacent to the load-bearing bottom side portion (7). The synthetic resin cup container according to claim 1 or 2, wherein (3) is formed. 4. The synthetic resin product according to claim 1, 2, or 3, wherein the wall thickness of the lightened cylindrical wall portion (8) is gradually decreased by increasing the diameter of the inner diameter of the lightened cylindrical wall portion (8). Cup container.

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