plastic bottles

Abstract

To provide a plastic bottle capable of suppressing decrease in rigidity and volume.SOLUTION: A plastic bottle 10 has a mouth part 20, a trunk part 30 and a bottom part 50. The trunk part 30 has an upper corner cylindrical part 31, a cylindrical part 32 and a lower corner cylindrical part 33. The upper corner cylindrical part 31 has a polygonal shape with a plurality of upper corner parts 34 formed in a horizontal cross section. The lower corner cylindrical part 33 has a polygonal shape with a plurality of lower corner parts 35 formed in a horizontal cross section. The upper corner cylindrical part 31 and the cylindrical part 32 are connected to each other by a first ridge line 41. The cylindrical part 32 and the lower corner part 33 are connected to each other by a second ridge line 42. A part of the first ridge line 41 that overlaps the upper corner part 34 when viewed from a height direction is positioned closer to the bottom part 50 side than the other parts of the first ridge line 41.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to plastic bottles. [Background technology]

[0002] Recently, plastic containers for holding contents such as food and drink have become common.

[0003] There is a demand for such plastic bottles to be lightweight overall. On the other hand, if the wall thickness of a plastic bottle is reduced in order to reduce the weight of the plastic bottle, the rigidity of the plastic bottle may decrease. In response to this, plastic bottles are known that can suppress the decrease in rigidity of the plastic bottle even when the wall thickness is reduced (for example, Patent Document 1). Patent Document 1 discloses a plastic bottle whose body has a rectangular tubular portion and a cylindrically drawn portion formed by drawing the rectangular tubular portion into a cylindrical shape at a predetermined height position. When the body has a rectangular tubular portion in this way, the storage efficiency of the plastic bottle can be improved when storing it in, for example, a cardboard box or a refrigerator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5282246 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the body of a plastic bottle has a rectangular tube portion and a cylindrically drawn portion, the capacity of the plastic bottle may be reduced.

[0006] The present disclosure has been made in consideration of these points, and aims to provide a plastic bottle that can suppress a decrease in rigidity and a decrease in volume. [Means for solving the problem]

[0007] A plastic bottle according to one embodiment has a mouth, a body, and a bottom, the body having an upper angular tube portion located closer to the mouth, a tubular portion located closer to the bottom than the upper angular tube portion, and a lower angular tube portion located closer to the bottom than the tubular portion, the upper angular tube portion having a polygonal shape with multiple upper corners in horizontal cross section, the lower angular tube portion having a polygonal shape with multiple lower corners in horizontal cross section, the upper angular tube portion and the tubular portion being connected to each other by a first ridge line, the tubular portion and the lower angular tube portion being connected to each other by a second ridge line, and the portion of the first ridge line that overlaps with the upper corner portion when viewed from the height direction is located closer to the bottom than the other portions of the first ridge line.

[0008] In one embodiment of the plastic bottle, the portion of the second ridge that overlaps the lower corner portion when viewed from the height direction may be located closer to the mouth than other portions of the second ridge.

[0009] A plastic bottle according to one embodiment has a mouth, a body, and a bottom, the body having an upper angular tube portion located closer to the mouth, a tubular portion located closer to the bottom than the upper angular tube portion, and a lower angular tube portion located closer to the bottom than the tubular portion, the upper angular tube portion having a polygonal shape in horizontal cross section with multiple upper corners, the lower angular tube portion having a polygonal shape in horizontal cross section with multiple lower corners, the upper angular tube portion and the tubular portion being connected to each other by a first ridge line, the tubular portion and the lower angular tube portion being connected to each other by a second ridge line, and the portion of the second ridge line that overlaps with the lower corner portion when viewed from the vertical direction is located closer to the mouth than the other portions of the second ridge line.

[0010] In the plastic bottle according to one embodiment, a plurality of horizontal grooves may be formed in the upper rectangular tube portion and the lower rectangular tube portion, respectively.

[0011] In one embodiment of the plastic bottle, at least a portion of the tubular portion may be constricted radially inwardly of the upper rectangular tubular portion and the lower rectangular tubular portion.

[0012] In one embodiment of the plastic bottle, the cylindrical portion may be provided with a plurality of panels, and each of the panels may have an elliptical shape.

[0013] In the plastic bottle according to one embodiment, each of the panels may extend in a direction inclined with respect to the height direction. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to suppress a decrease in rigidity and a decrease in volume. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing a plastic bottle according to one embodiment. [Figure 2] FIG. 2 is a front view (view taken along the arrow II in FIG. 1) showing a plastic bottle according to one embodiment. [Figure 3] FIG. 3 is a view taken along an arrow III in FIG. 1, showing a plastic bottle according to an embodiment. [Figure 4] FIG. 4 is a vertical cross-sectional view (cross-sectional view taken along line IV-IV in FIG. 2) showing a plastic bottle according to one embodiment. [Figure 5] FIG. 5 is a vertical cross-sectional view (cross-sectional view taken along line VV in FIG. 3) showing a plastic bottle according to one embodiment. [Figure 6] FIG. 6 is a plan view showing a plastic bottle according to one embodiment. [Figure 7] FIG. 7 is a horizontal cross-sectional view showing a plastic bottle according to one embodiment. [Figure 8] FIG. 8 is a diagram (corresponding to FIG. 3) for explaining the operation of the plastic bottle according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present disclosure will be described below with reference to the drawings. FIGS. 1 to 8 are diagrams illustrating an embodiment of the present disclosure. The following figures are schematic diagrams. Therefore, the size and shape of each part are appropriately exaggerated for ease of understanding. Furthermore, appropriate modifications can be made within the scope of the technical concept. In the following figures, identical parts are denoted by the same reference numerals, and some detailed descriptions may be omitted. Furthermore, the numerical values, such as dimensions, and material names of each component described in this specification are examples of an embodiment and are not limited thereto and may be appropriately selected and used. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are interpreted not only strictly but also to include substantially the same state.

[0017] First, a plastic bottle 10 according to this embodiment will be described with reference to Figures 1 to 7. In this specification, "upper" and "lower" refer to the upper and lower sides, respectively, of the plastic bottle 10 when it is held upright (Figures 1 to 5). In this specification, the "central axis CL" of the plastic bottle 10 refers to the central axis of the cylinder that forms the inner surface of the mouth portion 20 of the plastic bottle 10. The central axis CL of the plastic bottle 10 is a straight line that is perpendicular to the plane that forms the contact surface when the plastic bottle 10 is placed on the ground in an upright position.

[0018] In this specification, the term "height direction" refers to the direction along the central axis CL of the plastic bottle 10, and the term "radial direction" refers to the direction perpendicular to the central axis CL of the plastic bottle 10. The term "circumferential direction" refers to the circumferential direction of a circle centered on the central axis CL of the plastic bottle 10.

[0019] The plastic bottle 10 shown in FIGS. 1 to 5 is produced by preparing a preform obtained by injection molding and then subjecting this preform to biaxial stretch blow molding.

[0020] As shown in Figures 1 to 5, the plastic bottle 10 has a mouth 20, a neck 21 located below the mouth 20, a shoulder 22 located below the neck 21, a body 30 located below the shoulder 22, and a bottom 50 located below the body 30.

[0021] Of these, mouth portion 20 has a threaded portion 23 that screws onto a cap (not shown), and a flange portion 24 located below threaded portion 23. Note that a container containing the contents is obtained by filling plastic bottle 10 with a liquid or other content and screwing a cap onto mouth portion 20. The contents may be beverages, seasonings such as soy sauce, powdered food such as salt, solids such as coffee beans, or non-food items such as liquid detergent.

[0022] The neck portion 21 is located between the flange portion 24 and the shoulder portion 22, and has a generally cylindrical shape with a generally uniform diameter.

[0023] Shoulder 22 is located between neck 21 and body 30, and has a shape in which the diameter gradually increases from neck 21 toward body 30. Shoulder 22 has a substantially rectangular shape in a cross section parallel to a horizontal plane S on which plastic bottle 10 is placed (hereinafter also referred to as a horizontal cross section).

[0024] In this shoulder portion 22, a recessed portion 25 that recesses inward toward the plastic bottle 10 is formed. Thus, by forming the recessed portion 25 in the shoulder portion 22, for example, when a shrink label or the like is disposed around the plastic bottle 10, the shrink label can be easily peeled off using the recessed portion 25 as a starting point. As shown in FIG. 6, in the present embodiment, four recessed portions 25 are formed. The four recessed portions 25 are arranged at equal intervals along the circumferential direction. Specifically, each recessed portion 25 is formed on a diagonal line d of a quadrilateral formed by an upper corner cylindrical portion 31 described later in plan view. Further, the recessed portion 25 extends along the diagonal line d in plan view. Note that the number of recessed portions 25 is not limited to this.

[0025] Here, when the length of the recessed portion 25 is L (see FIG. 5), the width is W (see FIG. 6), and the depth is D (see FIG. 5), 0.5 < L / (W×D) < 5 it is preferable that the relationship is satisfied. Thus, by satisfying the relationship of 0.5 < L / (W×D), it is possible to suppress the values of the width W or the depth D with respect to the length L of the recessed portion 25 from becoming too large. For this reason, the buckling strength of the shoulder portion 22 can be increased. Further, by satisfying the relationship of L / (W×D) < 5, it is possible to suppress the values of the width W or the depth D with respect to the length L of the recessed portion 25 from becoming too small. Also in this case, the buckling strength of the shoulder portion 22 can be increased.

[0026] Further, the length L and the width W of the recessed portion 25 are W < L it is preferable that the relationship is satisfied. Thereby, the buckling strength of the shoulder portion 22 can be effectively increased. Further, by satisfying the relationship of W < L, when a shrink label or the like is disposed around the plastic bottle 10, the shrink label or the like can be easily disposed on the recessed portion 25.

[0027] Referring again to Figures 2 to 5, the body 30 has an upper angular tubular portion 31 located on the mouth 20 side, a tubular portion 32 located closer to the bottom 50 than the upper angular tubular portion 31, and a lower angular tubular portion 33 located closer to the bottom 50 than the tubular portion 32.

[0028] Of these, the upper rectangular tube portion 31 has a polygonal shape in horizontal cross section with a plurality of upper corner portions 34. Similarly, the lower rectangular tube portion 33 has a polygonal shape in horizontal cross section with a plurality of lower corner portions 35.

[0029] In this embodiment, as shown in FIG. 7 , the upper rectangular tube portion 31 has a quadrangular (square) shape in horizontal cross section with four upper corner portions 34. That is, the upper rectangular tube portion 31 has a quadrangular tube shape. Similarly, the lower rectangular tube portion 33 has a quadrangular (square) shape in horizontal cross section with four lower corner portions 35, and the lower rectangular tube portion 33 has a quadrangular tube shape. In this embodiment, the shapes of the upper rectangular tube portion 31 and the lower rectangular tube portion 33 are identical in horizontal cross section. Therefore, when viewed from the height direction, the upper corner portions 34 and the lower corner portions 35 overlap each other. Note that in this specification, the term "polygonal shape" also includes a shape with rounded corners of a polygon. Furthermore, the upper rectangular tube portion 31 and the lower rectangular tube portion 33 may each have a polygonal tube shape, such as an octagonal tube shape.

[0030] 2 to 5, multiple horizontal grooves 36 are formed in each of the upper rectangular tube portion 31 and the lower rectangular tube portion 33. These horizontal grooves 36 primarily function to absorb reduced pressure by contracting vertically when the pressure inside the plastic bottle 10 is reduced. The horizontal grooves 36 also serve to increase the strength of the upper rectangular tube portion 31 and the lower rectangular tube portion 33.

[0031] Each of the horizontal grooves 36 extends around the entire circumferential circumference of the body 30. The vertical width of each of the horizontal grooves 36 is uniform around the entire circumferential circumference. In the illustrated example, three horizontal grooves 36 are formed in the upper rectangular tube portion 31, and four horizontal grooves 36 are formed in the lower rectangular tube portion 33. However, the number of horizontal grooves 36 is not limited to this.

[0032] Next, the cylindrical portion 32 of the body portion 30 will be described. As shown in Figures 2 to 5, the cylindrical portion 32 is located between the upper rectangular cylindrical portion 31 and the lower rectangular cylindrical portion 33. The cylindrical portion 32 includes an upper expanded diameter portion 32a connected to the upper rectangular cylindrical portion 31, a cylindrical portion 32b located closer to the bottom 50 than the upper expanded diameter portion 32a, and a lower expanded diameter portion 32c located closer to the bottom 50 than the cylindrical portion 32b and connected to the lower rectangular cylindrical portion 33.

[0033] The upper expanded diameter portion 32a has a shape in which the outer edge widens radially outward as it approaches the upper rectangular tube portion 31. In this case, as shown in Fig. 4, in a first vertical cross section described below, the width of the upper expanded diameter portion 32a is approximately uniform along the vertical direction, and the width of the upper expanded diameter portion 32a is equal to the width of the upper rectangular tube portion 31. Here, the "first vertical cross section" refers to a cross section in a plane that includes the central axis CL of the plastic bottle 10 and that bisects the plastic bottle 10 in a front or side view.

[0034] On the other hand, as shown in FIG. 5 , in a second vertical cross section (described later), the upper expanded diameter portion 32a has a shape in which the diameter (width) gradually increases from the lower rectangular tube portion 33 toward the upper rectangular tube portion 31. That is, in the second vertical cross section, the upper expanded diameter portion 32a slopes radially outward as it extends upward. Here, the "second vertical cross section" refers to a cross section in a plane including the central axis CL and the diagonal line d. In this case, the angle θ1 between the outer surface of the upper expanded diameter portion 32a and the height direction may be 40° or more and 80° or less. By setting the angle θ1 to 40° or more, the height (vertical distance) of the upper expanded diameter portion 32a can be prevented from becoming too high. This prevents the height of the upper rectangular tube portion 31 from becoming too low. As a result, the volume of the upper rectangular tube portion 31 can be prevented from decreasing. Furthermore, by setting the angle θ1 to 40° or more, it is possible to improve the grip of the consumer's hand (fingers) on the upper expanded diameter portion 32a when the consumer grips the cylindrical portion 32 of the plastic bottle 10. Furthermore, by setting the angle θ1 to 80° or less, it is possible to prevent a decrease in the buckling strength of the body portion 30.

[0035] The cylindrical portion 32b has a generally cylindrical shape with a generally uniform diameter. The diameter of the cylindrical portion 32b is equal to the length of one side of the rectangle (square) formed by the upper rectangular tube portion 31 in a plan view. In this case, as shown in Fig. 4, the width of the cylindrical portion 32b is equal to the width of the upper rectangular tube portion 31 in a first vertical cross section. On the other hand, as shown in Fig. 5, the width of the cylindrical portion 32b is narrower than the width of the upper rectangular tube portion 31 in a second vertical cross section.

[0036] The lower expanded diameter portion 32c has a shape in which the outer edge widens radially outward toward the lower rectangular tube portion 33. In this case, as shown in FIG. 4, in the first vertical cross section, the width of the lower expanded diameter portion 32c is substantially uniform along the up-down direction and is equal to the width of the lower rectangular tube portion 33 (the width of the upper rectangular tube portion 31). On the other hand, as shown in FIG. 5, in the second vertical cross section, the lower expanded diameter portion 32c has a shape in which the diameter (width) gradually widens from the upper rectangular tube portion 31 toward the lower rectangular tube portion 33. That is, in the second vertical cross section, the lower expanded diameter portion 32c slopes radially outward as it extends downward. In this case, the angle θ2 formed between the outer surface of the lower expanded diameter portion 32c and the height direction may be 40° or more and 80° or less. By setting the angle θ2 to 40° or more, it is possible to prevent the height (vertical distance) of the lower expanded diameter portion 32c from becoming too high. This prevents the height of the lower rectangular tube portion 33 from decreasing, thereby preventing a decrease in the volume of the lower rectangular tube portion 33. Furthermore, by setting the angle θ2 to 80° or less, a decrease in the buckling strength of the body portion 30 can be prevented.

[0037] At least a portion of the tubular portion 32 is constricted radially inward relative to the upper rectangular tubular portion 31 and the lower rectangular tubular portion 33. This makes it easier for consumers to grip the tubular portion 32 of the plastic bottle 10. In particular, because at least a portion of the tubular portion 32 is constricted radially inward relative to the upper rectangular tubular portion 31, when a consumer grips the tubular portion 32 of the plastic bottle 10, the consumer's fingers can easily grip the body portion 30. In other words, when a consumer grips the tubular portion 32 of the plastic bottle 10, the consumer's hand (fingers) can hook onto the upper expanded diameter portion 32a. Therefore, when a consumer grips the tubular portion 32 of the plastic bottle 10, the consumer's fingers can easily grip the body portion 30. As a result, the grip of the plastic bottle 10 can be improved.

[0038] In this embodiment, the tubular portion 32, except for its central portion when viewed from the front or side, is constricted radially inward relative to the upper rectangular tubular portion 31 and the lower rectangular tubular portion 33 (hereinafter simply referred to as the "upper rectangular tubular portion 31, etc."). In this case, the amount of constriction of the tubular portion 32 radially inward relative to the upper rectangular tubular portion 31, etc. (hereinafter simply referred to as the "constriction amount of the tubular portion 32") gradually increases in the circumferential direction as it approaches the upper corner portion 34 (lower corner portion 35). Therefore, the amount of constriction of the tubular portion 32 is greatest at the portion of the tubular portion 32 that overlaps the upper corner portion 34 when viewed from the height direction.

[0039] On the other hand, as described above, in the first vertical cross section, the width of the upper expanded diameter portion 32a, the width of the cylindrical portion 32b, and the width of the lower expanded diameter portion 32c are each equal to the width of the upper rectangular tube portion 31 (the width of the lower rectangular tube portion 33) (see FIG. 4). Therefore, in the central portion of the cylindrical portion 32 when viewed from the front or side, the cylindrical portion 32 is not constricted radially inward more than the upper rectangular tube portion 31, etc.

[0040] Additionally, the diameter (width) of the tubular portion 32 is equal to or less than the width of the upper rectangular tubular portion 31 and the width of the lower rectangular tubular portion 33 over the entire circumference. This improves the storage efficiency when storing plastic bottles 10 in, for example, a cardboard box or a refrigerator.

[0041] Additionally, the tubular portion 32 is provided with a plurality of panels 37. In the illustrated example, the panels 37 are formed on the cylindrical portion 32b of the tubular portion 32. The panels 37 serve to increase the rigidity of the tubular portion 32. Each panel 37 has an elliptical shape. This increases the rigidity of the tubular portion 32 while improving the formability of the panels 37.

[0042] Each panel 37 extends in a direction inclined relative to the height direction, thereby increasing the rigidity of the tubular portion 32 against vertical and lateral loads. In this case, the angle θ3 (see FIG. 2) between the major axis of the panel 37 and the height direction may be 60° or more and 85° or less.

[0043] In the plastic bottle 10, the upper rectangular tube portion 31 and the tubular portion 32 are connected to each other by a first ridge 41. The tubular portion 32 and the lower rectangular tube portion 33 are connected to each other by a second ridge 42. The portion of the first ridge 41 that overlaps with the upper corner portion 34 when viewed from the height direction is located closer to the bottom 50 than the other portions of the first ridge 41. This allows for a larger volume of the upper rectangular tube portion 31. This prevents a decrease in the volume of the plastic bottle 10. Furthermore, because the vertical position of the first ridge 41 varies along the circumferential direction, the rigidity of the tubular portion 32 against vertical loads can be increased. This prevents deformation of the tubular portion 32 when a consumer grips the tubular portion 32 of the plastic bottle 10. This prevents the contents from spilling out of the plastic bottle 10 when a consumer grips the tubular portion 32 of the plastic bottle 10.

[0044] Furthermore, the portion of the second ridge 42 that overlaps the lower corner portion 35 when viewed from the height direction is located closer to the mouth portion 20 than the other portions of the second ridge 42. This allows the volume of the lower rectangular tubular portion 33 to be increased, thereby preventing a decrease in the volume of the plastic bottle 10. Furthermore, because the vertical position of the second ridge 42 varies along the circumferential direction, the rigidity of the tubular portion 32 can be increased.

[0045] Next, the bottom portion 50 will be described. As shown in Figures 2 to 5, the bottom portion 50 has a central portion 51 located in the center of the bottom portion 50, a peripheral portion 53 located on the periphery of the bottom portion 50, and a flat, annular ground portion 52 located between the central portion 51 and the peripheral portion 53. Of these, the ground portion 52 is the portion that comes into contact with the ground surface when the plastic bottle 10 is held upright. The ground portion 52 has a ring shape that is continuous in the circumferential direction.

[0046] Furthermore, the thickness of the ground contact portion 52 is not limited to this, but can be, for example, 0.09 mm or more and 0.40 mm or less. Having a thickness of 0.09 mm or more in the ground contact portion 52 can prevent the bottom portion 50 from popping out and becoming permanently deformed when the plastic bottle 10 is placed in a vending machine or dropped. Also, having a thickness of 0.40 mm or less in the ground contact portion 52 can reduce the weight of the plastic bottle 10.

[0047] Although not shown, for example, a plurality of ribs extending along the radial direction may be provided in the central portion 51 of the bottom portion 50.

[0048] The peripheral edge 53 of the bottom 50 and the lower rectangular tube portion 33 of the body 30 are connected to each other by a third ridge 43. The portion of the third ridge 43 that overlaps with the lower corner portion 35 when viewed from the height direction is located closer to the mouth 20 than the other portions of the third ridge 43. This increases the rigidity of the region near the bottom 50. In particular, the portion of the third ridge 43 that overlaps with the lower corner portion 35 when viewed from the height direction is located closer to the mouth 20 than the other portions of the third ridge 43, which increases the rigidity of the region near the bottom 50, especially the region near the lower corner portion 35.

[0049] However, the size of such plastic bottle 10 is not limited, and the bottle may be of any size. For example, the full capacity of plastic bottle 10 may be 200 ml to 2000 ml, preferably 300 ml to 1500 ml, and more preferably 450 ml to 1000 ml. For example, the full capacity of plastic bottle 10 may be 950 ml.

[0050] Furthermore, the weight of the plastic bottle 10 may be, but is not limited to, 10 g to 38 g, preferably 14 g to 28 g, when the full capacity is 2000 ml or less.

[0051] The plastic bottle 10 can also be produced by biaxially stretching and blow molding a preform made by injection molding a synthetic resin material. The primary material for the plastic bottle 10 can be a thermoplastic resin, particularly polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polylactic acid (PLA), polycarbonate (PC), etc. The plastic bottle 10 can also have a multilayer structure in which a barrier material layer is sandwiched between two polyethylene terephthalate layers. For example, a preform with a multilayer structure such as PET / MXD6 / PET can be produced and then biaxially stretched and blow molded to produce the plastic bottle 10, which is a multilayer container. The plastic bottle 10 can also be made from recycled plastic, which is produced by sorting, crushing, and cleaning used plastic products. The plastic bottle 10 can also be produced by various molding methods, such as biaxially stretching and blow molding, as well as direct blow molding.

[0052] Next, the operation of this embodiment having such a configuration will be described.

[0053] First, an empty plastic bottle 10 is prepared, and then the plastic bottle 10 is filled with a beverage or other content. In this embodiment, the portion of the first ridge 41 that overlaps the upper corner portion 34 when viewed from the height direction is located closer to the bottom 50 than the other portions of the first ridge 41. Additionally, the portion of the second ridge 42 that overlaps the lower corner portion 35 when viewed from the height direction is located closer to the mouth 20 than the other portions of the second ridge 42. This allows the volumes of the upper rectangular tubular portion 31 and the lower rectangular tubular portion 33 to be increased, allowing the plastic bottle 10 to be filled with a desired amount of content.

[0054] Next, the opening 20 is closed with a cap (not shown).

[0055] When a consumer drinks the contents, the consumer first grasps the body 30 of the plastic bottle 10, for example, by pinching the tubular portion 32 of the body 30 between their thumb and index finger, as shown in FIG. 8 . As described above, in this embodiment, the portion of the first ridge 41 that overlaps the upper corner 34 when viewed from the height direction is located closer to the bottom 50 than the other portions of the first ridge 41. Furthermore, the portion of the second ridge 42 that overlaps the lower corner 35 when viewed from the height direction is located closer to the mouth 20 than the other portions of the second ridge 42. In this way, the vertical positions of the first ridge 41 and the second ridge 42 vary along the circumferential direction, thereby increasing the rigidity of the tubular portion 32. This suppresses deformation of the tubular portion 32, allowing the consumer to lift the plastic bottle 10 without spilling the contents.

[0056] Furthermore, a portion of the tubular portion 32 is constricted radially inward relative to the upper angular tubular portion 31 and the lower angular tubular portion 33. This allows consumers to easily grip the tubular portion 32 of the plastic bottle 10. In particular, because a portion of the tubular portion 32 is constricted radially inward relative to the upper angular tubular portion 31, when a consumer grips the body 30 (tubular portion 32) of the plastic bottle 10, the upper expanded diameter portion 32a catches on the consumer's hand (fingers). This allows consumers to easily lift the plastic bottle 10.

[0057] As described above, according to this embodiment, the body 30 has an upper rectangular tube portion 31 located closer to the mouth 20, a tubular portion 32 located closer to the bottom 50 than the upper rectangular tube portion 31, and a lower rectangular tube portion 33 located closer to the bottom 50 than the tubular portion 32. Furthermore, the upper rectangular tube portion 31 has a polygonal shape with multiple upper corners 34 formed in a horizontal cross section, and the lower rectangular tube portion 33 has a polygonal shape with multiple lower corners 35 formed in a horizontal cross section. Furthermore, the upper rectangular tube portion 31 and the tubular portion 32 are connected to each other by a first ridge line 41, and the tubular portion 32 and the lower rectangular tube portion 33 are connected to each other by a second ridge line 42. Furthermore, the portion of the first ridge line 41 that overlaps with the upper corners 34 when viewed from the height direction is located closer to the bottom 50 than the remaining portion of the first ridge line 41. This allows the volume of the upper rectangular tube portion 31 to be increased. This prevents a decrease in the volume of the plastic bottle 10. Furthermore, because the vertical position of the first ridge 41 varies along the circumferential direction, the rigidity of the tubular portion 32 can be increased. This can reduce deformation of the tubular portion 32 when a consumer grips the tubular portion 32 of the plastic bottle 10. As a result, it can reduce the risk of the contents spilling out of the plastic bottle 10 when a consumer grips the tubular portion 32 of the plastic bottle 10.

[0058] Furthermore, according to this embodiment, the portion of the second ridge 42 that overlaps the lower corner portion 35 when viewed from the height direction is located closer to the mouth portion 20 than the other portions of the second ridge 42. This allows the volume of the lower rectangular tubular portion 33 to be increased, thereby preventing a decrease in the volume of the plastic bottle 10. Furthermore, because the vertical position of the second ridge 42 varies along the circumferential direction, the rigidity of the tubular portion 32 can be increased.

[0059] Furthermore, according to this embodiment, multiple horizontal grooves 36 are formed in each of the upper rectangular tube portion 31 and the lower rectangular tube portion 33. As a result, when the pressure inside the plastic bottle 10 is reduced, the reduced pressure can be absorbed by the horizontal grooves 36. Furthermore, the horizontal grooves 36 can increase the strength of the upper rectangular tube portion 31 and the lower rectangular tube portion 33.

[0060] Furthermore, according to this embodiment, at least a portion of the tubular portion 32 is constricted radially inward relative to the upper rectangular tubular portion 31 and the lower rectangular tubular portion 33. This makes it easier for consumers to grip the tubular portion 32 of the plastic bottle 10. In particular, because at least a portion of the tubular portion 32 is constricted radially inward relative to the upper rectangular tubular portion 31, when a consumer grips the body portion 30 (tubular portion 32) of the plastic bottle 10, the upper expanded diameter portion 32a catches on the consumer's hand (fingers). Therefore, when a consumer grips the tubular portion 32 of the plastic bottle 10, the consumer's fingers can easily grip the body portion 30. As a result, the grip of the plastic bottle 10 can be improved.

[0061] Furthermore, according to this embodiment, a plurality of panels 37 are provided on the cylindrical portion 32. Each panel 37 has an elliptical shape, which increases the rigidity of the cylindrical portion 32 and improves the formability of the panels 37.

[0062] Furthermore, according to this embodiment, each panel 37 extends in a direction inclined relative to the height direction, thereby increasing the rigidity of the tubular portion 32 against vertical and lateral loads.

[0063] The components disclosed in the above embodiments and modifications may be combined as needed, or some components may be omitted from all the components disclosed in the above embodiments and modifications. [Explanation of symbols]

[0064] 10 plastic bottles 20 Mouth 30 Torso 31 Upper square tube part 32 Cylindrical part 33 Lower rectangular tube part 34 Upper corner 35 Lower corner 36 horizontal groove 37 Panel 41 First edge 42 Second edge 50 bottom

Claims

1. It has a mouth, a body, and a bottom, The body portion is an upper rectangular tube portion located on the mouth portion side; a cylindrical portion located closer to the bottom than the upper rectangular cylindrical portion; a lower rectangular tubular portion located closer to the bottom than the tubular portion, The upper rectangular tube portion has a polygonal shape in horizontal cross section with a plurality of upper corner portions formed therein, the lower rectangular tube portion has a polygonal shape in horizontal cross section with a plurality of lower corner portions formed therein, the upper rectangular tube portion and the tube portion are connected to each other by a first ridge line, the cylindrical portion and the lower rectangular cylindrical portion are connected to each other by a second ridge line, A plastic bottle, wherein a portion of the first ridge that overlaps with the upper corner portion when viewed from the height direction is located closer to the bottom than other portions of the first ridge.

2. The plastic bottle according to claim 1, wherein the portion of the second ridge that overlaps with the lower corner portion when viewed from the height direction is located closer to the mouth than other portions of the second ridge.

3. 3. The plastic bottle according to claim 1, wherein a plurality of horizontal grooves are formed in the upper and lower rectangular tube portions.

4. The plastic bottle according to claim 1 , wherein at least a portion of the tubular portion is constricted radially inward relative to the upper and lower rectangular tubular portions.

5. The plastic bottle according to claim 1 , wherein the cylindrical portion is provided with a plurality of panels, each of which has an elliptical shape.

6. The plastic bottle according to claim 5 , wherein each of the panels extends in a direction inclined relative to the height direction.

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