US20010030166A1 - Plastic bottle - Google Patents

Abstract

A hot-fill type plastic bottle having a body, wherein said body has a octagonal cross-sectional shape, each of corners of the octagon is formed with a ridge wall, connecting walls are provided at both lateral sides of each of the ridge walls to form a pillar, a pressure reduction absorbing portion is formed between any two adjacently located ones of the ridge walls, and two connecting walls of one of the pillars form an angle between 60 and 115°. The rigidity of the pillar is raised. The bottle shows a pressure reduction absorbing effect similar to that of a conventional hexahedral bottle. In addition, the wide area of the shrink-wrap type label can be seen at a glance.

Description

BACKGROUND OF THE INVENTION
• This invention relates to a plastic bottle and, more particularly, to a hot-fill type plastic bottle.[0001]
• Plastic bottles provided at the body thereof with pressure reduction absorbing portions for hot-fill the liquid content are known. Hexahedral bottles having a body whose corners are rounded are marketed.[0002]
• However, when a shrink label is applied to the peripheral wall of a known hexahedral bottle, the label is inevitably divided by six.[0003]
• If a design, a mark, an explanation of the goods or the like is printed on two of six lateral surfaces of the bottle, such design or the like can be viewed at a glance when the viewer sees it along the radial line of the bottle. However, if the design or the like is printed on three or more of six lateral surfaces, the viewer can no longer see it at a glance, and has to rotate the bottle to entirely understand what is printed there.[0004]
• In order to freely design the mark or the like, and in order to recognize the design or the like at a glance, it may be considered to increase the number of lateral side to make the bottle almost cylindrical. However, as the number of lateral side increases, the pressure reduction absorbing portion area of the bottle is reduced to consequently reduce the pressure reduction absorbing effect thereof. Such a bottle can no longer be used for hot-fill applications. It is commonly believed that the maximal number of lateral sides of a polyhedral bottle is six if it is used for hot-fill applications.[0005]
SUMMARY OF THE INVENTION
• In view of the above problem, it is therefore the object of the present invention to provide a hot-fill type bottle having a body with a relatively large number of lateral sides so as to make the wrap film of the bottle to be easily viewed particularly in terms of design and printing, and to show a pressure reduction absorbing effect similar to that of conventional hexahedral bottles.[0006]
• According to the invention, the above object is achieved by providing a hot-fill type plastic bottle having a body, wherein said body has a octagonal cross-sectional shape, each of corners of the octagon is formed with a ridge wall, connecting walls are provided at both lateral sides of each of the ridge walls to form a pillar, a pressure reduction absorbing portion comprises a pressure reduction absorbing wall and the connecting wall, and is formed between any two adjacently located ones of the ridge walls, and two connecting walls of one of the pillars form an angle between 60 and 115°.[0007]
• Preferably, each of the pressure reduction absorbing walls is provided with a ridge-shaped or groove-shaped rib.[0008]
• The present invention provides the following advantages.[0009]
• As described above, according to the invention, the octagonal body is provided with the pillar at each of corners of the octagon, each of the pillars comprises the ridge wall and the connecting walls at both lateral sides of the ridge wall, and the connecting walls form the angle between 60 and 115°. Thus, the rigidity of the pillar is raised. In addition, since the pressure reduction absorbing portion is formed between any two adjacently located ones of the ridge walls, the bottle shows a pressure reduction absorbing effect similar to that of a conventional hexahedral bottle.[0010]
• In addition, since the ridge wall is provided, the wide area of the shrink-wrap type label can be seen at a glance.[0011]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic front view of an embodiment of bottle according to the invention.[0012]
• FIG. 2 is a schematic cross sectional view of the bottle of FIG. 1 taken along line A-A in FIG. 1.[0013]
• FIG. 3 is an enlarged schematic view of a pressure reduction absorbing portion of the embodiment of FIG. 1.[0014]
• FIG. 4 is a graph of the pressure reduction absorbing effect of the embodiment.[0015]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Now, the present invention will be described by referring to the accompanying drawings that illustrate preferred embodiments of the invention.[0016]
• Referring to FIG. 1, illustrating an embodiment of bottle according to the invention, a bottle “A” is a hot-fill type bottle made of synthetic resin such as PET, and is formed by oriented-blow molding to show an octagonal body.[0017]
• The bottle “A” comprises a[0018]neck1, ashoulder2, abody3 showing an octagonal cross section, and abottom4. An outer periphery of theneck1 is formed with athread5. A neck ring6 is projected outwardly under thethread5.
• A[0019]horizontal rib7 is formed between thebody3 and theshoulder2. Anarrow strip8 is arranged under thehorizontal rib7. Ahorizontal rib9 is formed between thebody3 and thebottom4. Anarrow strip10 is arranged on thehorizontal rib9.
• The[0020]body3 extends between theupper strip8 and thelower strip10. Thebody3 has a substantially octagonal cross sectional shape. Each of the corners of the octagon is formed with aridge wall11 axially extended. Each of theridge wall11 has an outwardly protruded or rounded cross sectional shape, and connects to theupper strip8 and thelower strip10. A pressurereduction absorbing portion12 is formed between any two adjacently located ones of theridge walls11.
• Each of the pressure[0021]reduction absorbing portions12 comprises a pressurereduction absorbing wall16, and a connectingwall14 which connects the pressurereduction absorbing wall16 and theridge wall11. More specifically, theconnecting wall14 connects with theupper strip8 and thelower strip10, and also with anedge13 of one of theridge walls11 and anedge13 of theadjacent ridge wall11. In other words, at both lateral sides of each of theridge walls11, twoconnecting walls14 are provided. The pressurereduction absorbing wall16 connects withinner edges15a,15b,15c,15dof the connectingwall14. Each of the pressurereduction absorbing wall16 is somewhat outwardly protruded or curved.
• While the[0022]wall16 is slightly outwardly curved in the illustrated embodiment, it may alternatively be completely flat.
• The pressure[0023]reduction absorbing wall16 is formed with arib17. In the illustrated embodiment, therib17 is concaved, extends axially along theridge walls11, and has an inverted U-shape at the top thereof and a U-shape at the bottom thereof. Although therib17 is a groove shaped rib in the illustrated embodiment, it may be a ridge-shaped rib.
• The[0024]bottom4 comprises a bottomperipheral wall20 extending downwardly from thehorizontal rib9, abottom end wall21, and abottom wall22 upwardly concaved from thebottom end wall21.
• The bottom[0025]peripheral wall20 is provided at a middle section thereof with ahorizontal rib23, and thebottom wall22 is provided with a plurality of radially -extending reinforcement ribs of a known type.
• Now, the more detailed structure, the function and the effect of the[0026]ridge walls11 and the pressurereduction absorbing portions12 of thebody3 will be described by referring to FIG. 3.
• Each of the[0027]ridge walls11 and theconnecting walls14a,14baxially provided adjacent to each of theridge walls11 form a pillar which raises the rigidity of the body. The connectingwall14aand the connecting wall14bdefine a pillar angle α.
• In this embodiment, the pillar angle α is between 60° and 115°, preferably not smaller than 75°.[0028]
• The bottle of this embodiment is made of 32 g or less of synthetic resin, and has a capacity of 500 ml. Each of the[0029]ridge walls11 of the illustrated embodiment has the outwardly curved surface, which curvature has 68 mm of a diameter “D”. Each of theridge walls11 has a width “w” of 5.35 mm. Any two adjacently located ones of theridge walls11 are separated by a distance “W” of 21 mm. As described above, the pressurereduction absorbing wall16 is outwardly curved, and thus has a diameter. The difference (or a height in a diametrical direction) “H” of the diameter “D” of theridge walls11 and the diameter of the pressurereduction absorbing wall16 is 2.99 mm.
• It should be noted, however, that the above described values of the dimensions of the body of the bottle can be modified appropriately according to the capacity and the profile of the bottle and according to the diameter of the ridge wall.[0030]
• Preferably, the dimension can vary according to the following relationship.[0031]
• W=1/3.5D to 1/2.8D[0032]
• H=1/25D to 1/15D[0033]
• w=1 to 6 mm[0034]
• In the case of conventional bottles having a hexagonal body, the pillar angle α was between 0 and 45°, and the pressure reduction absorbing effect was about 30 cc. On the other hand, according to the above described embodiment of the present invention, the pillar angle α is between 60° and 115°, preferably not smaller than 75°, which is larger than that of the conventional bottle. Thus, the pillars show an improved rigidity, and, in addition, the bottle shows a pressure reduction absorbing effect substantially same as that of a hexahedral bottle.[0035]
• Additionally, since each of the pressure[0036]reduction absorbing walls16 is provided with therib17, it can be formed stably without deformation of thewall16. In addition, therib17 reinforces the pressure reduction absorbing16 and the connectingwalls14, so that the rigidity of the pillars in an axial direction of the container (buckling strength) is increased as a result of the reinforcement of the connectingwalls14.
• Now, the present invention will be described by way of experiments to illustrate the function and the effect of the invention.[0037]
• [Experiments][0038]
• 32 g of preforms made of PET resin were biaxially oriented blow molded to form five bottles having a capacity of 529 ml and an octagonal body.[0039]
• Each of the bottles had the following dimensions; D=68 mm, H=2.99 mm, W=21 mm, w=5.35 mm. The pillar angle of the bottles was differentiated to produce five different types having respective pillar angles of 15°, 40°, 60°, 75° and 95°.[0040]
• Each of the bottles without the liquid content was subjected to thermal conditions equivalent to those of actual hot-fill operations (87° C. of water was filled, cooled and then removed), and then filled with water. The bottles filled with water were hermetically sealed at the neck, and subsequently the content was reduced by means of a syringe needle at a constant rate, to observe the limit capacity until which the pillars could maintain the proper profile (pressure reduction absorbing effect).[0041]
• Table 1 and the graph of FIG. 4 summarily shows the obtained results.[0042]

  TABLE 1
  The Relationship between the Pillar Angle and
  the Pressure Reduction Absorbing Effect

  	pillar angle	pressure reduction absorbing effect (cc)
  	15	15.0
  	40	20.0
  	60	24.5
  	75	27.3
  	95	29.8

• As seen from the results, it is recognized that if the pillar angle α is 75° or more, the rigidity of the pillars of a bottle according to the invention was improved, so as to show a pressure reduction absorbing effect similar to that of a hexahedral bottle.[0043]
• It will be appreciated from the graph of FIG. 4 that the bottle with the pillar angle α of 115° has the pressure reduction absorbing effect greater than that of the bottle with the pillar angle α of 75°.[0044]
• The bottle with a pillar angle of 60° shows a pressure reduction absorbing effect that is lower than that of a bottle with a pillar angle of 75° only by 10%, and hence is acceptable.[0045]
• While the above described bottles had specific values for H, W and w, it was also proved that a similar pressure reduction absorbing effect can be obtained when H=1/25 to 1/15D and W=1/3.5 to 1/2.8D.[0046]
• While the present invention is described above by way of an embodiment having an octagonal body, a bottle according to the invention may alternatively have a heptagonal or nonagonal body.[0047]

Claims (2)

1. A hot-fill type plastic bottle having a body, wherein

said body has a octagonal cross-sectional shape,

each of corners of the octagon is formed with a ridge wall,

connecting walls are provided at both lateral sides of each of the ridge walls to form a pillar,

a pressure reduction absorbing portion comprises a pressure reduction absorbing wall and the connecting wall, and is formed between any two adjacently located ones of the ridge walls, and

two connecting walls of one of the pillars form an angle between 60 and 115°.

2. The hot-fill type plastic bottle according to

claim 1

, wherein each of the pressure reduction absorbing walls is provided with a ridge-shaped or groove-shaped rib.

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