JP2009137636A - Plastic container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic container showing an excellent shock resistance against a shock such as a fall and capable of preventing a storing portion from being damaged. <P>SOLUTION: The plastic container includes a side surface part, a bottom surface connected to the side surface part to form a container lower corner X, and a rib-like protrusion provided downward below the lower corner on the outside of the container. A line connecting an end point Y on the outside of a lower end of the rib-like protrusion with the container lower corner X crosses a lower outer shape line α of the bottom surface and an inside outer shape line β of the rib-like protrusion, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plastic container.

In recent years, plastic containers have been widely used as containers for containing beverages and solids. A plastic container has many advantages such as light weight and excellent moldability as compared with other glass containers and metal containers, but conventionally, a thin-walled container has a problem of poor mechanical strength. In particular, when the contents are stored in a plastic container, the weight of the container increases. Therefore, if the container falls while the contents are stored, the container may be damaged. For such a problem, Patent Document 1 discloses a technique for adjusting the radius of curvature of the container inner lower corner as shown in FIG. 4A to increase the strength. Patent Document 2 discloses a technique for increasing the drop strength by adjusting the cross-sectional shape of the container bottom 41 as shown in FIG. 4B.
JP-A-10-264922 JP 2006-315726 A JP 2005-342684 A

  However, according to the knowledge of the present inventors, by changing the thickness and shape of the container inner lower corner to improve the impact resistance of the corner portion, or by adjusting the cross-sectional shape of the container bottom portion, the bottom surface portion and the side surface The technology such as improving the strength of the rib-like convex portion provided downward toward the outside of the bottom surface portion of the container at the lower corner formed by the portion, when a crack occurs in the lower part of the container including the rib-like convex portion, There was a case where the housing part such as the bottom part or the side part of the container was cracked.

  According to the knowledge of the present inventors, this is due to the fact that when the container is dropped, the load applied to the tip of the rib-like convex portion that is first grounded is directly transmitted to the bottom surface portion and the side surface portion of the container. In other words, if the container bottom and side parts have the same strength as the rib-like convex part or less strength than the rib-like convex part, the load due to impact reaches the container bottom part and side part via the plastic part. At least one of the bottom surface portion and the side surface portion is very easily broken. In particular, stress tends to be concentrated at the inner lower corner of the container, and is greatly affected by a load caused by a drop transmitted from the tip of the rib-shaped convex portion, and is easily cracked. For example, FIG. 5A shows an example of the propagation direction of the load due to the impact at the time of dropping in the case of the container lower part shape described in Patent Document 1 shown in FIG. 4A. The load caused by the impact transmitted from the lower outer tip of the convex portion is also transmitted to the lower inner corner of the container as indicated by the arrow in the figure. FIG. 5B shows an example of the propagation direction of a load due to an impact at the time of dropping in the case of the container lower part shape described in Patent Document 2 shown in FIG. 4B. The load due to the impact transmitted from the lower outer tip of the convex portion is also transmitted to the lower inner corner portion of the container as indicated by the arrow in the figure.

  The objective of this invention is providing the container shape which solves the said problem.

  In order to achieve the above object, the plastic container of the present invention has the following constitution.

  According to the present invention, a side surface portion, a bottom surface portion joined to the side surface portion to form a container lower corner, and a rib-like shape provided downward on the outer side of the container below at least a part of the container lower corner. A plastic container having a convex portion, wherein a line segment XY connecting an end point X outside the lower end of the rib-shaped convex portion and a container inner lower corner Y in a longitudinal section of the plastic container is a lower outer shape of the bottom surface portion. A plastic container is provided that is configured to intersect the line and the outer surface of the rib-shaped convex portion.

  Further, according to another aspect of the present invention, the side surface portion, the bottom surface portion joined to the side surface portion to form the container lower corner, and at least a part of the container lower corner are directed downward toward the outside of the container. A rib-shaped convex portion provided in the longitudinal direction of the plastic container, the thickness of the rib-shaped convex portion being d1, the outer end of the lower end of the rib-shaped convex portion, and the lower end of the side surface portion, The horizontal length is d2, the side surface thickness is d3, the horizontal length from the inner side lower end to the container inner lower corner is d4, the bottom surface thickness is a1, and the side surface lower end is When the length in the vertical direction from the end point on the lower outer side of the rib-shaped convex portion is L2, and the length in the vertical direction from the end point on the outer side of the bottom surface portion to the end point on the outer side of the lower end of the rib-shaped convex portion is L1, the bottom surface 2 over part of the perimeter Plastic container which satisfies the following equation is provided indicating the matter.

d3> d1 + d2
(D4 + d3-d2-d1) / a1> (d4 + d3-d2) / (a1 + L1)
Moreover, according to the preferable form of this invention, the said bottom face part is a polygon, The plastic container whose part around the said bottom face part is the corner | angular part of the said polygon is provided.

  Moreover, according to the preferable form of this invention, the plastic container which satisfy | fills said Formula over the perimeter of the said bottom face part is provided.

  According to a preferred embodiment of the present invention, in the longitudinal section of the plastic container, the plastic container further includes at least one installation auxiliary convex portion extending downward from the bottom surface portion on the inner side in the horizontal direction than the rib-shaped convex portion, and further the rib A plastic container in which the thickness d1 of the convex protrusion and the thickness d5 of the installation auxiliary convex part satisfy d5> d1 is provided.

  Moreover, according to another form of this invention, the water purifier using said plastic container is provided.

  In the present invention, the “rib-shaped convex portion” can have a shape as shown in FIG. 2A, for example. FIG. 2A shows a vertical cross-sectional view of the lower part of the plastic container. A convex part having a rib shape is provided on the outer side of the container bottom part of the container lower corner formed by the bottom part and the side part. It has been.

  In the present invention, “the thickness of the rib-like convex portion” refers to the thickness of the rib-like convex portion in the horizontal direction in the longitudinal section of the container.

  In the present invention, the “thickness of the side surface portion” refers to the horizontal thickness of the side surface portion of the container in the longitudinal section of the container. When the thickness of the rib-shaped convex portion varies depending on the rib-shaped convex portion, it means the thickness of the rib-shaped convex portion having the smallest thickness.

  In the present invention, the “thickness of the bottom surface portion” refers to the thickness in the vertical direction of the bottom surface portion in the longitudinal section of the container.

  In the present invention, “the container lower corner formed by joining the side surface portion and the bottom surface portion” is a place indicated by the corner X in the shape as shown in FIG. 2A, for example.

  ADVANTAGE OF THE INVENTION According to this invention, the plastic container which is excellent in impact resistance with respect to impacts, such as a fall, and can prevent a container part failure | damage can be obtained.

  Hereinafter, the example of the best embodiment of the present invention will be described with reference to the drawings, taking as an example the case of applying to a plastic container in a water purifier.

  Note that the present invention is not limited to the embodiments described below, and may be anything that can achieve the object of the present invention.

  FIG. 1 is a schematic view of a plastic container according to this embodiment. As shown in FIG. 1, the plastic container of the present embodiment includes a lid 1, a water receiver 2, a cartridge 3, and a container 4. The cartridge 3 can be easily attached to and detached from the water receiving portion 2 and is used in a state of being inserted into the water receiving portion 2. Moreover, the water receiving part 2 is fitted to the container 4 at the upper part, and the lower part of the container 4 is in a state in which the accommodating part 5 in which liquid or the like is accommodated is maintained as a space. The lid 1 is located above the water receiver 2 and the container 4. The cartridge 3 contains a filter medium such as activated carbon.

  In the state of FIG. 1, when tap water is put into the water receiving portion 2, the tap water passes through the cartridge 3 with its own weight, and at that time, free residual chlorine and the like are removed, and the accommodating portion 5 located below the container 4 as purified water. It collects in.

  In addition, when utilizing the plastic container of this embodiment as a water purifier, it is preferable to take the structure of the water purifier described in patent document 3 by the present applicants.

  The container 4 is a container having a rib-like convex portion, and is preferably a resin molded product such as polypropylene, acrylonitrile styrene, polystyrene, polycarbonate, acrylic, polyethylene, acrylonitrile butadiene styrene, or high impact polystyrene. In particular, acrylonitrile styrene and high impact polystyrene are preferable as plastic containers for water purifiers because of their excellent impact resistance, transparency, and heat resistance.

  Next, the best form of the container lower shape will be described.

  FIG. 2A is a cross-sectional view in a longitudinal section below a plastic container showing an embodiment of the present invention. FIG. 2B is a bottom view of a plastic container showing an embodiment of the present invention. FIG. 2C is a bottom view of a plastic container showing another embodiment of the present invention. FIG. 3A is a cross-sectional view in a longitudinal section below a plastic container showing an embodiment of the present invention. FIG. 3B is a bottom view of a plastic container showing an embodiment of the present invention. FIG. 3C is a bottom view of a plastic container showing another embodiment of the present invention.

  In the shape of the present embodiment, as shown in FIG. 6, a line segment XY connecting the end point Y on the lower outer side of the rib-shaped convex portion and the lower inner corner X of the plastic container is the lower outer line α and the rib on the bottom surface portion. And the outer shape line β of the inner surface of the convex portion. Although the load applied to the end X on the lower outer side of the rib-like convex portion is transmitted through the plastic portion when dropped, the line segment XY does not pass only inside the plastic in this shape. That is, the load applied to the end Y on the lower outer side of the rib-like convex portion when dropped is not directly transmitted to the accommodating portion corner, that is, the lower inner corner X of the container, and the container can be prevented from being damaged.

  Further, as shown in FIG. 7, the container side face thickness d3 is the horizontal length from the lower end of the container side face to the inner lower end of the rib-like convex part, that is, the horizontal between the end point outside the lower end of the rib-like convex part and the lower end of the side part. If the length d2 in the direction and the total thickness d1 of the rib-shaped convex portions are smaller than the total length d1, the thickness of the rib-shaped convex portions is smaller than the thickness of the container side portions, that is, the strength of the rib-shaped convex portions is smaller than the strength of the container side portions. . Further, the container side part thickness d3 is the horizontal length from the lower end of the container side part to the inner lower end of the rib-like convex part, that is, the horizontal length d2 between the end point outside the lower end of the rib-like convex part and the lower end of the side part and the rib When it becomes larger than the total length of the thickness d1 of the convex portions, the drop load applied to the rib-shaped convex portions is directly applied to the bottom surface portion, and the possibility that the bottom surface portion is damaged increases. In order to ensure the effect that the load applied to the end X on the lower outer side of the rib-like convex portion when it falls can be absorbed only by the rib-like convex portion, it is preferable to satisfy the following formula.

d3> d1 + d2
Further, in FIG. 8, in order that the impact load dropped from the end point Y on the lower outer side of the rib-shaped convex portion is not directly applied to the lower inner corner X of the container, a line γ that is vertically downward from the lower inner corner X of the container is used as a reference. The angle θ formed by the line Z-Z connecting the intersection Z between the rib-shaped convex portion inner side and the bottom surface outer side and the lower inner corner X of the container is the angle θ ′ formed by the reference line γ and the line segment XY. Larger is preferred. That is, a shape satisfying the following formula is good.

tanθ> tanθ '
Here, tan θ can be expressed as (d4 + d3−d2−d1) / a1 and tan θ ′ can be expressed as (d4 + d3−d2) / (a1 + L1) in FIG. Therefore, in the shape of FIG.

(D4 + d3-d2-d1) / a1> (d4 + d3-d2) / (a1 + L1)
Also, as shown in FIGS. 9 and 10, when the rib-shaped convex portion is chamfered or corner-curved, the thickness of the lower end of the rib-shaped convex portion is defined as the thickness of the rib-shaped convex portion. When the thickness of the rib-like convex portion varies depending on the rib, it is preferable to consider the thickness of the thinnest rib-like convex portion.

  When there is a rounded or chamfered shape at the outer side lower end of the side portion, it is preferable to consider the upper end of the side rounded or chamfered shape as the lower end of the side portion as shown in FIGS.

  Further, when the inner corner has a round shape or a chamfered shape, it is preferable to take the container inner corner X as shown in FIGS. When there is a radius at the inner corner, it is better to consider the intersection of the radius and the line connecting the center point O of the radius and the lower outer end Y of the rib-shaped convex portion as the container inner corner X. When the inner corner has a chamfered shape, the intersection of the inner side surface of the container and the chamfer should be considered as the container inner corner.

  In the present invention, the “installation auxiliary convex portion” may have a shape as shown in FIG. 3A, for example. FIG. 3A shows a vertical cross-sectional view below the plastic container, wherein at least one installation auxiliary convex portion extending downward from the bottom surface portion is provided on the inner side in the horizontal direction than the rib-shaped convex portion. The purpose is to form the ground contact surface when the is placed.

  The difference in the destruction mechanism will be described with reference to FIG. 15A showing an embodiment of the present invention and FIG. 15B showing a conventional embodiment.

  15A and 15B, the thickness d3 of the container side face part and the thickness a1 of the bottom face part are the same, and the difference is the shape of the rib-like convex part and the presence or absence of the rib-like convex part inner rib. FIG. 15C and FIG. 15D show the landing situation when FIG. 15A and FIG. The load due to the impact of the drop is transmitted to the plastic container vertically upward from the grounding point of the rib-like convex portion, that is, the end Y on the lower side of the rib-like convex portion as indicated by an arrow at the moment of dropping. Since the load is transmitted through the plastic container, as shown in FIG. 15D, the point X is likely to be affected by the load due to the impact of the drop, and the container side corners and the container side parts including the container lower corner X are easily broken. On the other hand, in FIG. 15C showing the embodiment of the present invention, since the drop ground point Y and the inner corner X are not directly connected by the plastic, the load due to the impact of the drop does not directly affect the inner corner X of the container.

  Next, how the rib-like convex part is configured in the bottom part will be described.

  FIG. 2B is a bottom view of a plastic container showing an embodiment of the present invention. In the bottom view of the container in FIG. 2B, rib-shaped convex portions are present at the corners of the polygon. In the case where the container bottom is a polygon, if the container is dropped, there is a high possibility of grounding from the corner of the polygon. Therefore, when the rib-like convex portions are at the corners of the polygon, it is possible to obtain an effect of preventing the container from being damaged by the higher rib-like convex portions. This rib-shaped convex part does not need to exist in all the corner | angular parts, and should just exist in at least one part of corner | angular part. The same applies to other embodiments.

  FIG. 2C is a bottom view of a plastic container showing another embodiment of the present invention. As shown in FIG. 2C, when rib-shaped convex portions exist over the entire circumference of the bottom surface portion, the container is prevented from being damaged by the rib-shaped convex portions even when the container is grounded from the side instead of the corner of the polygonal bottom surface portion. An effect can be acquired and it is preferable.

  FIG. 3A is a cross-sectional view in a longitudinal section below a plastic container showing an embodiment of the present invention. As shown in FIG.3A, when there is an installation auxiliary convex portion extending downward from the bottom surface portion of the container on the inner side in the horizontal direction from the rib-shaped convex portion, when the container is dropped and cracking or chipping of the rib-shaped convex portion occurs, In the shape of FIG. 2A, when the container is placed, the container is inclined and unstable. However, if there is an installation auxiliary convex part in addition to the rib-shaped convex part, the container drops even when the rib-shaped convex part is broken and shortened. The previous stable state can be maintained. In addition, when the installation auxiliary convex part is inside the rib-shaped convex part as shown in FIG. 3A, the possibility that the installation auxiliary convex part is cracked and shortened becomes very low, and the container is stable even if the container is dropped repeatedly. You can continue to put in the state. Since the installation auxiliary convex part prevents the inclination of the container when the container is installed before and after breakage of the rib-shaped convex part, it is preferably the same length as the rib-shaped convex part. It is desirable that both the convex portion and the installation auxiliary convex portion are grounded.

  2B and 2C, if the grounding auxiliary convex portion is inside the rib-shaped convex portion as shown in FIGS. 3B and 3C, the state where the container can be placed in a stable state can be continued for a longer time, and the effect of the rib can be further increased. It can be obtained for a long time.

  In FIG. 16, the thickness d1 of the rib-like convex part and the thickness d5 of the grounding auxiliary convex part inside the rib-like convex part have the following relationship.

d5> d1
If comprised as mentioned above, the intensity | strength of a grounding auxiliary | assistant convex part will become higher than the intensity | strength of a rib-shaped convex part. Therefore, the effect of preventing the container damage due to the drop load due to the damage of the rib-shaped convex part and the effect of placing the container in a stable state even after the rib-shaped convex part is damaged by the grounding auxiliary convex part inside the rib-shaped convex part are more reliable. Can be obtained simultaneously.

  FIG. 1 uses a plastic container to which this embodiment is applied as a water purifier. The water purifier has a large number of parts and is more expensive than a plastic container intended only to contain liquid, so it is desirable that it can be used for a long time. It is preferable to use a plastic container to which the embodiment is applied.

Hereinafter, the present embodiment will be described in more detail by way of examples, but the scope of the present invention is not limited by these examples.
[Example 1]
As a resin constituting the plastic container, acrylonitrile styrene (AS) resin (manufactured by Asahi Kasei Chemicals) was used. A plastic container having a shape to which the present embodiment shown in FIG. 16 was applied was produced by injection molding of this resin. The dimensions of the obtained container are shown in Table 1.

Using the properties of plastic containers that are easily damaged by injection molding in a low-temperature environment, leave the resulting container in an ambient temperature of -10 ° C or lower for 5 hours or more in an empty state, leaving only the container empty The strength of the plastic was evaluated by a forced test that immediately dropped onto the concrete from a height of 1 m. After dropping, the container returned to room temperature, and then water was poured into the container, and it was confirmed whether water had leaked from the side or bottom of the housing. Such an operation was repeated up to 20 times, and it was confirmed how many times the water leak occurred. Note that the initial posture of the container when dropped was the position where the bottom surface of the container was horizontal to the concrete surface. The results are shown in Table 2. Even if the number of samples (hereinafter referred to as N) was three and all dropped 20 times of the maximum number of drops, no water leakage occurred.
[Comparative Example 1]
Except for the thickness and length of the rib-shaped convex portion, a plastic container having a conventional shape shown in FIG. 17 was produced in the same manner as in Example 1, which did not satisfy the expression corresponding to Condition 1 of Claim 2. That is, the drop load applied to the rib-shaped convex portion is such that the container side portion thickness d3 is larger than the total length of the horizontal length d2 of the lower end of the rib-shaped convex portion and the lower end of the side portion and the thickness d1 of the rib-shaped convex portion. There is a high possibility that is directly added to the bottom surface. The dimensions of the obtained container are shown in Table 1.

The same test as in Example 1 was performed using the obtained container. The results are shown in Table 2. At N = 3, water leakage was confirmed by a total of 10 or fewer drops.
[Comparative Example 2]
The conventional plastic container shown in FIG. 18 has rib-shaped convex portions and ribs and does not satisfy the expression corresponding to the condition 2 of claim 2, that is, the line segment XY passes through only the plastic portion. Evaluation similar to Example 1 was performed. The same AS resin as in Example 1 was used as the resin. The dimensions are shown in Table 1. The results are shown in Table 2. At N = 3, one was estimated to be the number of drops of 20 or more, which was estimated to be the effect of the rib-like convex portion, but two were confirmed to have water leakage after 10 or less drops, as in Comparative Example 1.
[Comparative Example 3]
Using the same resin as in Example 1, the same evaluation as in Example 1 was performed on the container having no rib-shaped convex portion shown in FIG. The same AS resin as in Example 1 was used as the resin. The dimensions are shown in Table 1. The results are shown in Table 2. At N = 3, water leakage was confirmed after a total of 5 or fewer drops.

  The present invention can be applied not only to water purifiers, but also to pots for tea and water, sealed containers for foods, and small items, but the application range is not limited to these.

The schematic of the plastic container of this embodiment is shown. It is a schematic sectional drawing in the plastic container longitudinal section which shows one Embodiment of this invention. It is a bottom view of the plastic container which shows one Embodiment of this invention. It is a bottom view of the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a bottom view of the plastic container which shows one Embodiment of this invention. It is a bottom view of the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of a prior art. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of a prior art. It is a schematic sectional drawing in the longitudinal cross-section below the plastic container which shows the form of the destruction mode in FIG. 4A. It is a schematic sectional drawing in the longitudinal section below a plastic container which shows the form of the destruction mode in Drawing 4B. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the vertical section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of a prior art. It is a schematic sectional drawing in the longitudinal cross-section below the plastic container which shows the form of the destruction mode in FIG. 15A. It is a schematic sectional drawing in the longitudinal cross-section below the plastic container which shows the form of the destruction mode in FIG. 15A. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of this invention. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of a prior art. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of a prior art. It is a schematic sectional drawing in the longitudinal section below the plastic container which shows one Embodiment of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Cover 2: Water receiving part 3: Cartridge 4: Container 5: Storage part 41: Container bottom part 42 of a prior art product 42: Container side part 43 of a prior art product 43: Rib-shaped convex part 51 of a prior art product 51: Conventional technique Container bottom part 52 of product: Side surface part of container of conventional technology 53: Rib-shaped convex part of conventional product d1: Thickness of rib-shaped convex part d2: Distance between side surface and rib side surface d3: Thickness of side surface part L1: Ground surface L2: Length from the lower end of the side surface portion L2: Length from the ground contact surface to the outside of the bottom surface portion a1: Thickness of the bottom surface portion X: Lower corner inside the container Y: End portion on the outer side of the rib-shaped convex portion Z: Ribbed convex shape Intersection point between the inner side and the outer side of the bottom surface part O: Center point of the lower corner radius of the inner side of the container α: Line indicating the outer side of the bottom surface part in the lower sectional view of the container β: Line indicating the inner side surface of the rib-shaped convex part Below the container Line drawn from point X to the longitudinal in the plane view theta: acute angle formed by the line γ and the line segment X-Z θ ': angle of acute angle the line γ and the line segment X-Y

Claims (6)

A plastic having a side surface, a bottom surface joined to the side surface to form a container lower corner, and a rib-like convex portion provided downward toward the outside of the container below at least a part of the container lower corner. In the longitudinal section of the plastic container, a line segment connecting an end point outside the lower end of the rib-like convex portion and a container lower corner is a lower outline of the bottom portion and an inner side outline of the rib-like convex portion A plastic container characterized by being configured to cross each other. A plastic having a side surface, a bottom surface joined to the side surface to form a container lower corner, and a rib-like convex portion provided downward toward the outside of the container below at least a part of the container lower corner. In the longitudinal cross section of the plastic container, the thickness of the rib-like convex part is d1, the horizontal length between the outer end of the lower end of the rib-like convex part and the outer lower end of the side part is d2, and the side face The thickness of the part is d3, the horizontal length from the inner side lower end of the side surface part to the container inner lower corner is d4, the thickness of the bottom part is a1, and the lower end of the side surface part to the inner end of the lower end of the rib-like convex part When the length in the vertical direction is L2, and the length in the vertical direction from the end point outside the bottom surface portion to the end point outside the bottom end of the rib-like convex portion is L1, two conditions are shown over a part of the periphery of the bottom surface portion. To satisfy Plastic container for the butterflies.
Condition 1: d3> d1 + d2
Condition 2: (d4 + d3-d2-d1) / a1> (d4 + d3-d2) / (a1 + L1) The plastic container according to claim 2, wherein the bottom surface portion is a polygon, and a part of the periphery of the bottom surface portion is a corner portion of the polygon. The plastic container according to claim 2, wherein the formula according to claim 2 is satisfied over the entire circumference of the bottom surface portion. In the longitudinal section of the plastic container, the plastic container further includes at least one installation auxiliary convex portion extending downward from the bottom surface portion on the inner side in the horizontal direction than the rib-shaped convex portion, and further, the thickness d1 of the rib-shaped convex portion and the installation auxiliary convex portion The plastic container according to any one of claims 2 to 4, wherein the thickness d5 of the portion satisfies d5> d1. The water purifier using the plastic container in any one of Claims 1-5.

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