JP2014076863A - Plastic container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic container whose bottom part can easily be deformed, and for which the total height of the container can be suppressed.SOLUTION: A plastic container 10 has an opening part 11, a barrel part 12 and a bottom part 13. The bottom part 13 has an inflection part 13a and a grounding part 13b connected to an outer peripheral edge of the inflection part 13a through a fulcrum part 13c. When the bottom part 13 is pushed up, the inflection part 13a is dented inward around the fulcrum part 13c. Since the fulcrum part 13c is positioned above the grounding part 13b, a position of the grounding part 13b is kept fixed so that the dispersion in the total height of the container can be suppressed.

Description

  The present invention relates to a plastic container, and more particularly to a plastic container capable of easily deforming a bottom portion and suppressing variations in the overall height of the container.

  Conventionally, a plastic container having a mouth portion, a trunk portion, and a bottom portion is known. In such a plastic container, after filling the contents in a state of low temperature to normal temperature, capping is performed in a state where the bottom is pushed up and deformed.

JP 2006-8200 A

  In the case of a container having the same capacity, hot filling raises the liquid level by reducing the pressure after cooling. On the other hand, aseptic filling is performed at room temperature, the liquid level does not increase without reducing the pressure. When using aseptic filling, the bottom is pushed up in order to adjust the height of the liquid level depending on the filling method. In the case of a conventional plastic container, a large pushing force is required for pushing up the bottom.

  In response to the above problems, the present inventors have developed a plastic container that can easily push up the bottom as in Patent Document 1. By using the plastic container described in Patent Document 1, it is possible to easily push up and capping the bottom after filling at room temperature, and to easily absorb the reduced pressure by deforming the bottom when the container is decompressed.

  By the way, when the plastic container described in Patent Document 1 is used, when the bottom portion is pushed up, the ground contact portion of the bottom portion changes, and thus the total height of the plastic container may vary. In this case, a problem does not occur as a final product, but a defect may occur during the manufacturing process.

  The present invention has been made in view of such points, and an object of the present invention is to provide a plastic container in which the bottom can be easily deformed and variation in the overall height of the container can be suppressed.

  The present invention includes a mouth portion, a trunk portion, and a bottom portion having a depressed portion, the bottom portion being a bent portion disposed along the periphery of the depressed portion, and an outer peripheral edge of the bent portion via a fulcrum portion. A plastic container characterized in that when the bottom part is pressed upward, the inflection part is indented inward with the fulcrum part as the center, and the fulcrum part is located above the grounding part. is there.

  According to the present invention, the inflection portion has a flat surface that is inclined radially inward and downward from the fulcrum portion, and an inner peripheral wall surface that extends from the flat surface toward the depressed portion side. It is a container.

  The present invention is the plastic container characterized in that the length along the radial direction of the flat surface of the inflection part is 3.0 mm or more and 25% or less of the outer diameter of the body part.

  The present invention is characterized in that the fulcrum part is located 0.5 to 3.0 mm radially inward from the lower end of the grounding part and 0.5 to 2.0 mm above the lower end of the grounding part. It is a plastic container.

  The present invention is the plastic container characterized in that the distance from the lower end of the grounding portion to the top wall of the depressed portion at the bottom is 25 to 40% of the outer diameter of the trunk portion.

  The present invention is the plastic container characterized in that the radius of curvature of the fulcrum portion is 0.5 to 2.0 mm.

  According to the present invention, the bottom can be easily pushed up and deformed. For this reason, it can be filled in a state where the bottom is pushed up easily when filling at room temperature. Moreover, since the ground contact location of the container can be kept constant, variations in the overall height of the container after filling can be suppressed.

The front view which shows one Embodiment of the plastic container by this invention. The perspective view which looked at the plastic container by this invention from the bottom part side. Fig. 2 is a vertical sectional view showing the bottom of a plastic container according to the present invention. The bottom view of the plastic container by this invention. The schematic sectional drawing which shows the bottom part of the plastic container by this invention. The bottom view which shows embodiment of the plastic container in which the taper-shaped surrounding wall was formed in the quadrangle | tetragon. The bottom view which shows embodiment of the plastic container in which the taper-shaped surrounding wall was formed in the octagon. The bottom view which shows embodiment of the plastic container in which the taper surrounding wall was formed in the hexagon. The schematic sectional drawing which shows the effect | action at the time of pushing up the bottom part of the plastic container by this invention. The front view which shows the comparative example of a plastic container. The front view which shows the comparative example of a plastic container.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 9 are views showing an embodiment of a plastic container according to the present invention. In the present specification, “upper” and “lower” refer to the upper and lower sides of the plastic container 10 in an upright state (FIG. 1), respectively.

  As shown in FIGS. 1 to 5, the plastic container 10 has a cylindrical shape as a whole, and is a biaxially stretched blow molded preform formed by injection molding a synthetic resin material. In addition, it is preferable to use a thermoplastic resin, especially PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate) as a material of the preform, that is, the plastic container 10.

  Such a plastic container 10 includes a mouth portion 11, a body portion 12, and a bottom portion 13. Among these, the body part 12 is formed with a plurality of recesses 12a for easily deforming the body part 12 by increasing or decreasing the internal pressure.

  Further, a lateral rib 21 extending in the circumferential direction is provided at a lower portion of the body portion 12, and the strength of the body portion 12 is reinforced by the lateral rib 21.

  The bottom portion 13 has a depressed portion 14 that is depressed toward the inside at a central portion thereof. Further, the bottom portion 13 is in contact with the inflection portion 13a disposed along the periphery of the depressed portion 14, and a grounding surface that is in contact with a reference surface S such as a table and is connected to the outer periphery of the inflection portion 13a through a fulcrum portion 13c. Part 13b. Among these, the grounding part 13b is formed over the circumferential direction of the bottom part 13. An annular outer wall surface 13g is formed on the outer periphery of the grounding portion 13b. In addition, the grounding part 13b is arrange | positioned in the peripheral vicinity of the bottom part 13, and the fulcrum part 13c and the inflection part 13a are located in the radial inside from the grounding part 13b.

  On the other hand, the inflection part 13 a is formed over the circumferential direction of the bottom part 13. The inflection portion 13a includes a flat surface 13d inclined inward in the radial direction from the fulcrum portion 13c and an inner peripheral wall surface 13e extending obliquely upward from the flat surface 13d toward the depressed portion 14 side. And have. The inflection portion 13a is recessed inwardly with the fulcrum portion 13c as the center when the bottom portion 13 is pressed upward as will be described later. On the other hand, the position of the grounding portion 13b hardly changes even when the bottom portion 13 is pressed upward.

  The fulcrum portion 13c is located above the ground contact portion 13b and is located above the flat surface 13d of the inflection portion 13a. Furthermore, since the flat surface 13d is positioned above the ground contact portion 13b, the inflection portion 13a does not contact the reference surface S.

  Further, an inner step portion 13f is formed between the inner peripheral wall surface 13e and the depressed portion 14 along the circumferential direction.

  As shown in FIGS. 2 to 5, the depressed portion 14 has a tapered peripheral wall 14 a inclined toward the inside and a top wall 14 b connected to the upper end thereof. Of these, the tapered peripheral wall 14a includes a first peripheral wall portion 14c and a second peripheral wall portion 14d that are inclined with respect to the reference plane S at different angles, is formed in a pentagon shape, and is provided with a ridge line 14e. Yes. The inclination angle of each of the peripheral wall portions 14c and 14d with respect to the reference plane S is suitably 45 ° to 70 °. Reference numeral 14g denotes a transition region between the second peripheral wall portion 14d and the top wall 14b. The ridge line 14e acts as a beam that receives the gravity of the contents, and enhances the effect of preventing the depression 14 from hanging downward. Note that the polygonal ridge line 14e and the corner side 14f may be a straight line, a gentle R, or a concave curve. Moreover, it is preferable that the top wall 14b is located above the horizontal rib 21 provided below the trunk portion 12.

  By the way, as shown in FIG. 5, the outer diameter (body diameter) D of the body part 12 is 55 to 70 mm, preferably 60 to 70 mm (capacity 240 to 360 ml).

  Further, the distance H from the lower end (reference surface S) of the ground contact portion 13b to the top wall 14b is 25 to 40%, preferably 25 to 35% of the trunk diameter D. If the distance H is less than 25% of the body diameter, the plastic container 10 is poorly seated due to the influence of gravity and heat from the heated contents until the depressed portion 14 hangs down until reaching the reference plane S. Become. On the other hand, if the distance H exceeds 40% of the body diameter, the stability of the moldability is deteriorated and the shape of the bottom 13 is difficult to be obtained, which is not preferable.

  Further, the fulcrum part 13c is preferably located 0.5 to 3.0 mm inward in the radial direction from the lower end of the grounding part 13b (symbol d in FIG. 5), and 0.5 from the lower end of the grounding part 13b (reference plane S). It is preferable to be located up to 2.0 mm (symbol h in FIG. 5). Further, the radius of curvature of the fulcrum part (symbol R in FIG. 5) is preferably 0.5 to 2.0 mm. By defining the position and shape of the fulcrum part 13c in this way, when the bottom part 13 is pushed up and deformed, the inflection part 13a can be easily recessed with the fulcrum part 13c as the center. Further, it is possible to hold the grounding portion (grounding portion 13b) of the plastic container 10 at a fixed position and suppress variations in the overall height of the container.

  Further, in FIG. 5, the length A (along the radial direction) of the flat surface 13d can be set as appropriate between 3.0 mm or more and 25% or less of the trunk outer diameter. Generally, as the length A of the flat surface 13d is increased, the force for pushing up the bottom 13 of the plastic container 10 can be reduced. If the length A of the flat surface 13d is less than 3.0 mm, the force necessary to push up the bottom 13 of the plastic container 10 becomes too large, which is not preferable. On the other hand, when the length A of the flat surface 13d exceeds 25% of the outer diameter of the body portion, it is difficult to secure the depressed portion 14, which is not preferable.

  The plastic container 10 can also be formed as a multilayer molded bottle having two or more layers. That is, by extrusion molding or injection molding, for example, the intermediate layer has gas barrier properties and light shielding properties such as MXD6, MXD6 + cobalt salt, PGA (polyglycolic acid), EVOH (ethylene vinyl alcohol copolymer) or PEN (polyethylene naphthalate). A multilayer bottle having gas barrier properties and light shielding properties may be formed by extrusion molding a preform composed of three or more layers as the resin (intermediate layer), and then blow molding. Such an intermediate layer is preferably provided in at least the body 12 of the plastic container 10. In addition, it is preferable to provide an intermediate layer in the region other than the depressed portion 14 in the bottom portion 13. This is because this portion may cause delamination (delamination) when subjected to an impact such as a case dropping. In order to have gas barrier properties and light shielding properties, a blend bottle in which thermoplastic resins are blended may be formed as well as multilayers.

  In the present embodiment, the tapered peripheral wall 14a is formed in a pentagonal shape. However, a tapered peripheral wall 14a as shown in FIG. 6 is formed in a bottom, and a tapered peripheral wall 14a as shown in FIG. A bottom portion formed in an octagon shape and a bottom portion in which a tapered peripheral wall 14a as shown in FIG. 8 is formed in a hexagon shape are also possible. 6 to 8, the same parts as those in the embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals.

  Next, the operation of the present embodiment having such a configuration will be described.

  When capping the plastic container 10, the bottom portion 13 of the plastic container 10 is pushed upward and is capped in this state. That is, the mouth portion 11 of the plastic container 10 is held by the neck grip mechanism, and then the depressed portion 14 of the bottom portion 13 is pushed upward from below by the bottom pushing mechanism. Next, the plastic container 10 is capped with the depressed portion 14 of the bottom portion 13 pushed up.

  Thus, with the bottom 13 of the plastic container 10 pushed upward, the mouth 11 is sealed with a cap (not shown), and the inside of the plastic container 10 is kept in a reduced pressure state.

  As described above, the bottom portion 13 is pushed up at the time of capping. According to the present embodiment, the inflection portion 13a arranged along the periphery of the depression portion 14 is recessed inward with the fulcrum portion 13c as a center. (See the two-dot chain line in FIG. 9). For this reason, the bottom 13 can be easily pushed upward.

  That is, when the bottom part 13 is pushed up, the fulcrum part 13c becomes a base part when it is recessed inward, and the whole bottom part 13 can be pushed up easily.

  On the other hand, even when the bottom portion 13 is pushed up, the grounding portion of the plastic container 10 (that is, the grounding portion 13b of the bottom portion 13) is held at a substantially constant height position. Thereby, the container total height after filling is kept constant, and the dispersion | variation in a container total height can be suppressed.

  As described above, according to the present embodiment, the inflection portion 13a arranged along the periphery of the depressed portion 14 dents inwardly around the fulcrum portion 13c when the bottom portion 13 is pressed upward, and this fulcrum. The part 13c is located above the grounding part 13b. Accordingly, the bottom portion 13 can be easily pushed up and deformed, and can be capped with the bottom portion 13 pushed up easily during capping. Moreover, since the grounding location (grounding part 13b) of the plastic container 10 can be held at a fixed height position, variations in the overall height of the container after filling can be suppressed.

  Next, specific examples of the present invention will be described.

  First, four plastic containers 10 corresponding to the embodiment shown in FIGS. 1 to 5 were prepared (Examples 1 to 4). Of these, Example 1 has a length A (see FIG. 5) of the flat surface 13d of 4.0 mm, and Example 2 has a length A of the flat surface 13d of 8.0 mm. . In Example 3, the length A of the flat surface 13d is 12.0 mm, and in Example 4, the length A of the flat surface 13d is 3.0 mm.

  Next, as a comparative example, a plastic container 100 as shown in FIG. 10 was prepared (Comparative Example 1). In the plastic container 100, the bottom portion 103 has a grounding portion 103a and a circumferential protrusion 103b that protrudes outward. The circumferential protrusion 103b is located on the outer side in the radial direction of the ground contact portion 103a. Moreover, as shown in FIG. 11, a conventional plastic container 10 without a circumferential protrusion 103b protruding outward was prepared (Comparative Example 2). 10 and 11, reference numeral 101 indicates a mouth portion, and reference numeral 102 indicates a trunk portion.

  Next, a push-up test of the bottom portions 13 and 103 was performed on the plastic containers 10 and 100 of Examples 1 to 4 and Comparative Examples 1 and 2. Furthermore, the total height change amount of the plastic containers 10 and 100 after pushing up the bottom parts 13 and 103 was measured.

These results are shown below.

  As is clear from the above test results, in Examples 1 to 4, when compared with Comparative Example 1, the total height change amount could be kept small. In particular, in Examples 1 to 3, when compared with Comparative Example 1, (1) the amount of change in total height could be kept small, and (2) the load for pushing up the bottom could be made comparable or small.

  In Examples 1 to 4, compared with Comparative Example 2, (1) the total height change amount could be suppressed to the same level, and (2) the load for pushing up the bottom could be reduced.

DESCRIPTION OF SYMBOLS 10 Plastic container 11 Mouth part 12 trunk | drum 12a recessed part 13 bottom part 13a inflection part 13b grounding part 13c fulcrum part 13d flat surface 13e inner peripheral wall surface 13f inner side step part 13g outer wall surface 14 depression part 14a taper-shaped peripheral wall 14b top wall 14c 1st wall 14d Second wall portion 14e Edge line 14f Corner side 14g Transition region 21 Horizontal rib

Claims (6)

The mouth,
The torso,
A bottom portion having a depression,
The bottom has an inflection part arranged along the periphery of the depression, and a grounding part connected to the outer periphery of the inflection part via a fulcrum part,
The inflection part dents inward around the fulcrum part when the bottom part is pressed upward,
A plastic container, wherein the fulcrum part is located above the grounding part.   The inflection portion has a flat surface that is inclined inward and downward in the radial direction from the fulcrum portion, and an inner peripheral wall surface that extends from the flat surface toward the depressed portion side. Plastic container.   The plastic container according to claim 2, wherein a length along the radial direction of the flat surface of the inflection portion is 3.0 mm or more and 25% or less of the outer diameter of the trunk portion.   The fulcrum part is located 0.5 to 3.0 mm inward in the radial direction from the lower end of the grounding part, and is located 0.5 to 2.0 mm above the lower end of the grounding part. The plastic container according to any one of claims 1 to 3.   The plastic container according to any one of claims 1 to 4, wherein a distance from the lower end of the grounding portion to the top wall of the depressed portion at the bottom is 25 to 40% of the outer diameter of the trunk portion.   The plastic container according to any one of claims 1 to 5, wherein the fulcrum has a radius of curvature of 0.5 to 2.0 mm.

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