Plastic container

Abstract

The present invention provides a resin container that can ensure the rigidity necessary to maintain its shape and suppress inappropriate deformation when the pressure difference between the inside and outside of the container changes. [Solution] A resin container 1 including a cylindrical body 5 is provided with a first body 10 having a first side portion 12 that curves in an arc shape on either the outer or inner side of the body 5 on a cross section perpendicular to the axis AX of the body 5, and is arranged between a plurality of first corner portions 11, and is provided with ribs 8, and a second body 20 having a second side portion 22 that curves less to the outer or inner side on a cross section than the first side portion 12, and is arranged between a plurality of second corner portions 21.

Description

Technical Field

[0001] The present invention relates to a resin container having a cylindrical body portion with a plurality of corners.

Background Art

[0002] As a resin container for storing beverages and the like, there is known a resin container having a cylindrical body portion with a plurality of corners, and as the body portion, a first body portion and a second body portion having different cross-sectional shapes perpendicular to the axis are provided (for example, Patent Document 1). In the resin container of Patent Document 1, the corners of the first body portion are curved in an arc shape with a relatively large radius of curvature, and flat side portions are arranged between the corners to improve the adhesion of roll labels. On the other hand, in the second body portion, flat side portions having a relatively large length in the cross section are arranged between the corners to form the corners relatively small, and the overall cross-sectional shape of the second body portion is set larger outside than that of the first body portion, so as to improve the anti-tipping effect during the conveyance of the container.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the resin containers described above, the pressure difference between the inside and outside of the container may change after filling with liquid contents such as beverages, causing the container to deform. For example, the container may deform due to a decrease in internal pressure as the liquid contents evaporate. Container deformation can lead to various problems. For example, deformation can impair the aesthetic appeal of the container. If a container stored in a vending machine deforms, it may cause problems such as jamming or simultaneous discharge of multiple bottles. As a countermeasure against internal pressure reduction, attempts have been made to add a textured surface called a pressure-absorbing panel to the body of the container, absorbing the deformation caused by the pressure reduction and suppressing overall container deformation. However, pressure-absorbing panels have low rigidity against compressive loads in the lateral direction, i.e., perpendicular to the axis of the body. Therefore, if the thickness of the container is reduced to make it lighter, the container may deform easily, and the aforementioned problems when stored in a vending machine may become more likely to occur. The container described in Patent Document 1 above does not take such problems into consideration.

[0005] Therefore, the present invention aims to provide a resin container that can ensure the rigidity necessary to maintain the shape of the container and can suppress inappropriate deformation of the container by causing partial deformation when the pressure difference between the inside and outside changes. [Means for solving the problem]

[0006] A resin container according to one aspect of the present invention is a resin container including a cylindrical body, the body comprising: a first body having a first side portion that curves in an arc shape on either the outer or inner side of the body on a cross section perpendicular to the axis of the body, arranged between a plurality of first corner portions, and provided with ribs; and a second body having a second side portion that curves less to one side than the first side portion on the cross section, arranged between a plurality of second corner portions. [Brief explanation of the drawing]

[0007] [Figure 1] A front view of a bottle according to one embodiment of the present invention. [Figure 2] A plan view of the bottle in Figure 1. [Figure 3] Bottom view of the bottle in Figure 1. [Figure 4] Cross-sectional view of the first section of the torso along line IV-IV in Figure 1. [Figure 5] Cross-sectional view of the second body section along the VV line in Figure 1. [Figure 6] This figure shows an example of the results of a simulation of the deformation of various parts of the bottle when the internal pressure is reduced. [Modes for carrying out the invention]

[0008] A resin container according to one embodiment of the present invention will be described below with reference to Figures 1 to 6. This embodiment is an example of applying the present invention to a resin bottle used as a container for beverage products, as an example of a resin container. The bottle is a resin molded product manufactured by a biaxial stretch blow molding method using PET resin or the like as the material. The capacity of the bottle may be set as appropriate. As shown in Figures 1 to 4, the bottle 1 has a mouth portion 2, a neck portion 3, a shoulder portion 4, a body portion 5, and a bottom portion 6. In Figure 1, the bottle 1 is shown in an upright state, that is, with the bottom portion 6 facing downwards and the mouth portion 2 facing upwards. The vertical direction when the bottle is in an upright state corresponds to the axial direction of the bottle 1, and the direction in which the bottle 1 revolves around its axis AX corresponds to the circumferential direction of the bottle 1. In the following description, the top and bottom of the bottle 1 will be distinguished based on the upright state.

[0009] The mouth portion 2 is cylindrical with a relatively small diameter extending in the axial direction. The outer circumference of the mouth portion 2 is provided with a male threaded portion 2a for attaching a cap (not shown). The neck portion 3 extends coaxially downward from the lower end of the neck ring 3a with approximately the same diameter. The shoulder portion 4 extends from the lower end of the neck portion 3 toward the body portion 5, gradually expanding in size. The body portion 5 is formed to extend downward in a cylindrical shape along the axial direction from the lower end of the shoulder portion 4. As is clear from Figures 2 and 3, the body portion 5 is formed into a cylindrical shape that is generally a rounded quadrilateral when viewed from the axial direction, by arranging the side portions 5b between four outwardly expanding corner portions 5a. This type of body portion 5 is sometimes referred to as a rectangular tube. Details of the body portion 5 will be described later.

[0010] The bottom portion 6 is connected to the lower end of the body portion 5 and is a bottom lid that closes the lower end of the bottle 1 when it is upright. The mouth portion 2, neck portion 3, shoulder portion 4, body portion 5, and bottom portion 6 are arranged coaxially on a common axis AX. Therefore, axis AX corresponds to the overall axis of the bottle 1, and this axis AX coincides with the axis of the body portion 5. Also, the circumferential direction of the body portion 5 coincides with the circumferential direction of the bottle 1. However, the shoulder portion 4, body portion 5, and bottom portion 6 do not necessarily have to be arranged coaxially with respect to the mouth portion 2 and neck portion 3. For example, the body portion 5 and bottom portion 6 may be arranged eccentrically with respect to axis AX. The bottom portion 6 may be provided with a plurality of groove-shaped ribs extending radially from its center for the purpose of reinforcement.

[0011] As shown in Figure 1, the torso 5 includes a first torso 10 and a second torso 20. The first torso 10 is located on the upper side of the torso 5 and connects to the shoulder 4. The second torso 20 is located on the lower side of the torso 5 and connects to the bottom 6. The ratio of the axial height H1 from the upper end to the lower end of the first torso 10 to the axial height H2 from the upper end to the lower end of the second torso 20 may be set appropriately considering the balance of the respective functions of the first torso 10 and the second torso 20, which will be described later.

[0012] Multiple reinforcing ribs 8 are provided on the first body section 10 at appropriate intervals in the axial direction. In Figure 1, some of the ribs 8 are typically indicated by reference numerals. Each rib 8 is provided as a groove-shaped rib that encircles the body section 5 in the circumferential direction. The ribs 8 do not necessarily have to extend parallel to the body section 5, as long as they are provided to reinforce the first body section 10. The ribs 8 may be provided so as to meander up and down while encircling the body section 5, or they may be provided so as to be slightly inclined with respect to the circumferential direction of the body section 5. Furthermore, the ribs 8 do not necessarily have to encircle the body section 5. The ribs 8 may be provided within a range of the circumferential direction of the body section 5. Multiple ribs 8 may be provided so as to intersect each other. The ribs 8 may be formed as protruding ribs that bulge outwards from the body section 5. The ribs 8 may include both groove-shaped ribs and protruding ribs.

[0013] Figure 4 shows the cross-sectional shape of the first body section 10, and Figure 5 shows the cross-sectional shape of the second body section 20. However, Figure 4 shows the cross-sectional shape of the first body section 10 at a different position from the rib 8. The cross-sectional shape referred to here means the shape on a cross section perpendicular to the axis AX of the body section 5. As shown in Figure 4, the first body section 10 has a cross-sectional shape in which the first side sections 12 are arranged between four first corner sections 11. The first corner sections 11 constitute part of the corner section 5a of the body section 5, and the first side sections 12 constitute part of the side section 5b of the body section 5. The cross-sectional shapes of the first corner sections 11 and the first side sections 12 are set to bulge outwards in an arc shape toward the outside of the body section 5. The radius of curvature R12 of the first side sections 12 is set to be sufficiently larger than the radius of curvature R11 of the first corner sections 11. When a quadrilateral Q1 is imagined that is tangent to each first side section 12, that quadrilateral Q1 is a square. Therefore, when the distance between a pair of first side portions 12 that face each other in the vertical and horizontal directions in Figure 4 is defined as the opposing distance, this opposing distance is equal to the length L1 of one side of the quadrilateral Q1. Because the first corner portion 11 is curved outward from the body portion 5 in an arc with a radius of curvature R11, the diagonal dimension D1 between the first corner portions 11 is smaller than the diagonal dimension of the quadrilateral Q1. The diagonal dimension D1 is determined according to the radii of curvature R11 and R12 of the first corner portion 11 and the first side portion 12, respectively, and the opposing distance L1 between the first side portions 12.

[0014] On the other hand, as shown in Figure 5, the second body portion 20 has a cross-sectional shape in which the second side portion 22 is positioned between four second corner portions 21. The second corner portions 21 constitute another part of the corner portion 5a of the body portion 5, and the second side portion 22 constitutes another part of the side portion 5b of the body portion 5. The cross-sectional shape of the second corner portions 21 is set to bulge outwards in an arc shape toward the outside of the body portion 5. The cross-sectional shape of the second side portion 22 is set to extend linearly between the second corner portions 21, and as a result the second side portion 22 is planar. Therefore, the radius of curvature of the second side portion 22 is infinite, and its reciprocal, the curvature, is zero. In other words, if the degree of curvature of the first side portion 12 and the second side portion 22 toward the outside of the body portion 5 is evaluated by the curvature of each side portion 12 and 22 toward the outside of the body portion 5, the degree of curvature of the second side portion 22 is smaller than the degree of curvature of the first side portion 12.

[0015] When a rectangle Q2 is imagined that is in contact with each second side portion 22, that rectangle Q2 is a square. Therefore, when the distance between a pair of second side portions 22 that are opposite each other in the vertical and horizontal directions in Figure 5 is defined as the opposing distance, that opposing distance is equal to the length L2 of one side of rectangle Q2. Furthermore, the opposing distance L2 between the second side portions 22 is equal to the opposing distance L1 between the first side portions 12. By making the opposing distances L1 and L2 coincide, for example, the stability can be increased when a bottle 1 is placed on its side, or when multiple bottles 1 are stacked on top of each other in a horizontal position.

[0016] Since the second corner 21 is curved outward from the body 5 in an arc with a radius of curvature R21, the diagonal dimension D2 between the second corners 21 is smaller than the diagonal dimension of the quadrilateral Q2. Because the second side surface 22 is planar, the diagonal dimension D2 is determined by the radius of curvature R21 of the second corner 21 and the distance L2 between the second side surfaces 22. In the illustrated example, the distance L2 between the second side surfaces 22 is set to be equal to the distance L1 between the first side surfaces 12, while the radius of curvature R21 of the second corner 21 is set to be somewhat larger than the radius of curvature R11 of the first corner 11, so that the diagonal dimension D2 is set to be larger than the diagonal dimension D1. When the diagonal dimension D2 between the second corners 21 is set to be larger than the diagonal dimension D1 between the first corners 11, it is possible to increase the circumferential width of the second side surface 22, that is, the length of the second side surface 22 on the cross-section in Figure 5, and thereby relatively increase the area of ​​the second side surface 22, compared to when the diagonal dimension D2 is set to be less than or equal to the diagonal dimension D1.

[0017] With the bottle 1 described above, the first body portion 10 is provided with reinforcing ribs 8, thereby increasing the rigidity of the first body portion 10. Moreover, since the first side portion 12 of the first body portion 10 is curved in an arc shape toward the outside of the body portion 5, when the inside of the bottle 1 becomes depressurized, the first side portion 12 itself can function as a wall surface that resists deformation toward the inside of the bottle 1 and suppresses that deformation. This makes it possible to impart to the bottle 1 the rigidity necessary to maintain its shape.

[0018] On the other hand, since the second side surface portion 22 of the second barrel portion 20 is formed in a planar shape, the second side surface portion 22 is more likely to deform with respect to a load in the direction toward the inside of the bottle 1 as compared with the first side surface portion 12. Therefore, when the inside of the bottle 1 is in a decompressed state, it is possible to make the second side surface portion 22 function as a wall surface for absorbing deformation. By forming the second barrel portion 20 in a shape without ribs, the decompression absorption function by the second side surface portion 22 can be more effectively exhibited. Further, since the diagonal dimension D2 in the second barrel portion 20 is set as described above and the area of the second side surface portion 22 is relatively large, the decompression absorption function of the second side surface portion 22 can be further enhanced.

[0019] As described above, in the bottle 1 of the present embodiment, while ensuring the rigidity necessary for maintaining the shape of the bottle 1 by the first barrel portion 10, the second barrel portion 20 can absorb the deformation caused by the internal decompression and suppress the overall deformation of the bottle 1.

[0020] The results of simulating the amount of deformation of each part of the bottle 1 when the inside of the bottle 1 described above is in a decompressed state will be described. The conditions of the simulation are as follows. · Bottle capacity: 500 mL · Dimensions of each part of the bottle: Face-to-face distances L1, L2 = 59.1 mm Diagonal dimension D1 = 67.6 mm Diagonal dimension D2 = 68.6 mm Radius of curvature R11 of the first corner portion = 17.07 mm Radius of curvature R12 of the first side surface portion = 125 mm Radius of curvature R21 of the second corner portion = 18.08 mm Axial height H1 of the first barrel portion = 114 mm Axial height H2 of the second barrel portion = 35.5 mm · Internal pressure of the bottle: After filling the bottle with the minimum allowable amount of water, a pressure change corresponding to the amount of water evaporation of 6 mL after 6 months was caused inside the bottle assuming that 6 mL of water was removed.

[0021] An example of the simulation results is shown in Figure 6. The shade of gray in the figure correlates with the magnitude of the deformation, with darker areas indicating a larger deformation. The letters x, y, and z attached to the second body in the figure indicate the axis direction set for analyzing the deformation and are unrelated to the magnitude of the deformation. As is clear from the results in Figure 6, it was confirmed that the second side portion 22 of the second body portion 20 deforms relatively large, while the deformation of the first body portion 10 is significantly reduced. Furthermore, the change in the face-to-face distance L2 between the second side portions 22 before and after depressurization is generally less than 2 mm, confirming that deformation of the second side portions 22 does not cause deformation that affects the entire bottle 1.

[0022] The present invention is not limited to the embodiments described above and may be implemented in any form with appropriate modifications or changes. For example, the axial positional relationship between the first body section 10 and the second body section 20 is not limited to the example where the first body section 10 is positioned above the second body section 20. For example, the first body section 10 may be positioned below and the second body section 20 above. The second body section 20 may be positioned in the middle of the body section 5, with the first body section 10 positioned above and below it. In any case, as long as the body section 5 includes the first body section 10 and the second body section 20, the positional relationship between each body section 10, 20 may be set as appropriate.

[0023] The second body section 20 does not necessarily have to be formed in a shape without ribs. Ribs may be provided on the second body section 20, for example, at the second corner 21, or on a portion of the second side section 22, as long as the pressure absorption function of the second side section 22 is not impaired. The first body section 10 and the second body section 20 do not necessarily have to be formed in a rounded quadrilateral cross-sectional shape. Each body section 10, 20 may be formed in a polygonal shape having five or more corners. For example, each body section 10, 20 may be formed to have a roughly hexagonal or octagonal cross-sectional shape. The cross-sectional shape of each body section 10, 20 does not necessarily have to be a regular polygon with equal side lengths; the lengths of the sides may be differentiated. For example, in the examples in Figures 4 and 5, the quadrilaterals Q1 and Q2 may be rectangular. The first body section 10 and the second body section 20 may have different numbers of corners.

[0024] In the above-described embodiment, the first side portion 12 of the first body portion 10 is set to curve outward in an arc shape on a cross section perpendicular to the axis AX in order to increase resistance to reduced pressure inside the bottle 1, but the present invention is not limited to such examples. If the pressurization inside the bottle 1, i.e., the change in the internal and external pressure difference due to the increase in pressure, becomes a problem, the cross-sectional shape of the first side portion 12 may be set to curve inward in an arc shape on the inside of the body portion 5. For example, if an increase in the internal pressure of the bottle 1 is expected due to a rise in the temperature of the environment in which the bottle 1 is placed, if a relative increase in the internal pressure is expected due to a decrease in the external pressure of the bottle 1, or if an increase in the internal pressure is expected due to changes in properties such as fermentation inside the bottle 1, the first side portion 12 may be curved inward in an arc shape on the inside of the body portion 5 in order to deal with these pressure increases.

[0025] The second side portion 22 of the second body portion 20 does not necessarily have to be formed in a planar shape. If the first side portion 12 curves outward from the body portion 5 to accommodate internal pressure reduction, the second side portion 22 only needs to be formed such that the degree of outward curvature of the body portion 5 is smaller than that of the first side portion 12. A planar second side portion 22 is one example, and as described above, the outward curvature of the second side portion 22 is zero. As other examples, the second side portion 22 may be formed to curve outward from the body portion 5 in an arc shape with a smaller curvature than the first side portion 12, or the second side portion 22 may be formed to curve inward from the body portion 5 in an arc shape. In either case, the second side portion 22 is more easily deformed than the first side portion 12 by loads acting inward from the body portion 5, and is able to exhibit the pressure absorption function described above.

[0026] On the other hand, if the first side portion 12 curves inward towards the body portion 5 to accommodate internal pressure, the second side portion 22 should be formed such that the degree of inward curvature of the body portion 5 is smaller compared to the first side portion 12. A planar second side portion 22 is one example of this, and the inward curvature of the second side portion 22 is zero. As other examples, the second side portion 22 may be formed to curve inward towards the body portion 5 in an arc shape with a smaller curvature than the first side portion 12, or the second side portion 22 may be formed to curve outward towards the body portion 5 in an arc shape. In either case, the second side portion 22 is more easily deformed than the first side portion 12 by loads acting outward towards the body portion 5, and is able to exhibit a pressure absorption function.

[0027] As is clear from the above explanation, the first side portion 12 is formed to curve in an arc shape to either the outside or inside of the body portion 5 in a cross section perpendicular to the axis AX of the body portion 5, and the second side portion 22 is set such that the degree of curvature to the side in which the first side portion 12 curves is smaller than that of the first side portion 12 in a cross section perpendicular to the axis AX. When the second side portion 22 is curved to the other side in the opposite direction to the first side portion 12, the curvature of the second side portion 22 to one side is a negative value and is within a range smaller than the curvature of the first side portion 12 to one side. Therefore, even in that case, the degree of curvature of the second side portion 22 to one side can be evaluated as smaller than that of the first side portion 12. When the second side portion 22 is formed in a planar shape, it is advantageous because the second side portion 22 preferentially deforms and absorbs the pressure change regardless of whether the pressure inside or outside the bottle 1 increases relatively. The curvature of the first corner 11, the first side surface 12, and the second corner 21 does not necessarily have to be set to a constant value. The curvature may be appropriately varied within the same corner or side surface. The same applies when a curve is applied to the second side surface 22.

[0028] In the above configuration, the cross-sectional shapes of the first corner 11 and the second corner 21 are arc-shaped, but each corner 11 and 21 may be connected by a plane that is inclined at a certain angle between adjacent side surfaces 12 and 21, for example, at an angle of 45° to each side of the quadrilaterals Q1 and Q2 in Figures 4 and 5, resulting in a so-called chamfered shape. The relative sizes of the diagonal dimensions D1 and D2 are not limited to the above configuration, and the diagonal dimension D2 may be set to be less than or equal to the diagonal dimension D1. The relative sizes of the face-to-face distances L1 and L2 are not limited to the above configuration, and one of the face-to-face distances L1 and L2 may be set to be larger than the other.

[0029] The resin container of the present invention is not limited to examples where it is configured as a bottle for holding beverages. Various liquids such as seasonings, medical drugs, and cosmetic liquids, as well as various semi-solid substances such as gels, sols, powders, and other materials may be the contents of the container. The resin container of the present invention may be formed into any suitable shape, as long as it has a cylindrical body with multiple corners. The resin used as the material for the container is not limited to PET resin, and various resins may be used as the material.

[0030] Various aspects of the present invention derived from the embodiments and modifications described above are described below. In the following description, corresponding components shown in the accompanying drawings are indicated in parentheses to facilitate understanding of each aspect of the present invention, but this does not mean that the present invention is limited to the illustrated forms.

[0031] A resin container (1) according to one aspect of the present invention is a resin container including a cylindrical body (5), the body including a first body (10) having a first side portion (12) that curves in an arc shape on either the outer or inner side of the body on a cross section perpendicular to the axis (AX) of the body, arranged between a plurality of first corner portions (11), and provided with ribs (8), and a second body (20) having a second side portion (22) on the cross section that curves less to one side than the first side portion, arranged between a plurality of second corner portions (21).

[0032] In the resin container of the above embodiment, the rigidity of the first body can be increased by providing ribs on the first side surface of the first body. Moreover, since the first side surface of the first body is curved in an arc toward either the outside or the inside of the body, the first side surface can function as a wall surface that resists deformation caused by the pressure difference between the inside and outside of the resin container and suppresses such deformation. This makes it possible to impart the rigidity necessary for maintaining the shape to the resin container. On the other hand, the second side surface of the second body is formed to have a smaller degree of curvature toward the same side as the first side surface, so it is more susceptible to deformation when subjected to loads caused by the pressure difference between the inside and outside compared to the first side surface. Therefore, it is possible to make the second side surface function as a wall surface that absorbs deformation due to the pressure difference. This makes it possible to realize a resin container that can secure the rigidity necessary for maintaining the shape and can suppress inappropriate deformation of the container by causing partial deformation when the pressure difference between the inside and outside changes.

[0033] In the above embodiment, the following matters may be further added. These various matters may be applied in appropriate combinations, provided they do not conflict with each other.

[0034] In the above embodiment, the second side portion of the second body does not need to have ribs. By eliminating the ribs from the second side portion, the second side portion can be easily deformed in response to the pressure difference between the inside and outside of the container, and the second side portion can reliably function as a wall surface that absorbs deformation caused by the pressure difference.

[0035] The second side portion may be a planar shape that extends linearly along the cross-section. This allows the second side portion to be easily deformed in response to the pressure difference between the inside and outside of the container. Regardless of whether the pressure inside the container changes to a greater or lesser value relative to the external pressure, the second side portion can be deformed to absorb the deformation caused by the pressure difference.

[0036] The diagonal dimension (D2) between the second corners on the aforementioned cross-section may be greater than the diagonal dimension (D1) between the first corners. This allows for a relative increase in the length of the second side surface on the cross-section perpendicular to the axis of the body, thereby increasing the area of ​​the second side surface and ensuring that the second side surface functions reliably as a wall surface that absorbs deformation due to pressure differences.

[0037] The distance between the first side portions (L1) and the distance between the second side portions (L2) may be equal to each other. This increases the stability when the container is placed on its side or when multiple containers are stacked on top of each other in a horizontal position.

[0038] The first side portion may be curved in an arc shape on the outside of the body portion. In this case, when the pressure inside the container becomes reduced relative to the outside, the first side portion itself can function as a wall surface that resists deformation inward of the container and suppresses that deformation. This makes it possible to impart to the container the rigidity necessary to maintain its shape against internal pressure reduction. [Explanation of symbols]

[0039] 1 bottle 5 Torso 8 Ribs 10 First fuselage 11 First corner 12 First side part 20 Second Fuselage Section 21 Second corner 22 Second side part AX fuselage axis D1, D2 Diagonal dimensions L1, L2 face-to-face distance

Claims

1. A resin container including a cylindrical body, The aforementioned torso is, A first body having a first side portion that curves in an arc shape on either the outer or inner side of the body on a cross section perpendicular to the axis of the body, and having ribs provided, A second body portion having a second side portion, on the cross-section, whose degree of curvature toward one side is smaller than that of the first side portion, arranged between a plurality of second corner portions, A resin container containing [something].

2. The resin container according to claim 1, wherein the second side portion of the second body portion does not have ribs.

3. The resin container according to claim 1, wherein the second side portion is a planar shape that extends linearly on the cross-section.

4. The resin container according to claim 1, wherein the diagonal dimension between the second corners on the cross-section is greater than the diagonal dimension between the first corners.

5. The resin container according to claim 1, wherein the distance between the first side portions and the distance between the second side portions are equal to each other.

6. The resin container according to any one of claims 1 to 5, wherein the first side portion is curved in an arc shape outward from the body portion.

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