JP2018108829A - Plastic bottle and filled body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a square-type plastic bottle that is hardly squeezed while having stiffness and excellent in holding property while having lightweight property.SOLUTION: A plastic bottle includes a mouth part 10, a shoulder part 20, a barrel part 30 and a bottom part 40 sequentially in an axial direction. The barrel 30 has an upper-side square cylindrical part 50 constituted of a plurality of flat surface parts 31 and a corner part 32 connecting the flat surface parts 31 adjacent to each other in a circumferential direction. The upper-side square cylindrical part 50 has a peripheral groove 51 circling around PET bottle 1. The peripheral groove 51 has a constant width over the whole circumference and a depth in a middle part 31m in the flat surface part 31 smaller than that in a peripheral part 31p in the flat surface part 31.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a plastic bottle and a filling body, and more particularly to a weight-reduced plastic bottle and a filling body structure.

  As containers filled with beverages, plastic bottles, especially PET (PolyEthylene Terephthalate) bottles are often used. The market for large PET bottles is expanding due to demand for stockpiling and the impact of diversification of daily life. However, large PET bottles are difficult to hold because the weight increases due to the large volume of the filled bottle and the waistline becomes large.

  Patent Document 1 includes a mouth portion, a trunk portion, a shoulder portion, and a bottom portion, and the trunk portion is located at the approximate center in the height direction and has a waist portion whose outer peripheral dimensions are narrower than other portions. Are formed on the outer surface portion of the body portion in the circumferential direction, and are formed mainly to increase the rigidity, and are substantially centered in the height direction. A plastic bottle is disclosed that is formed on the front side and the back side of the trunk so that a gripping depression located approximately in the center in the left-right direction overlaps the waist.

Japanese Patent Laid-Open No. 2006-094240

  In the plastic bottle of Patent Document 1, the hollow portion for gripping is located approximately in the center in the height direction of the body portion, and gripping the vicinity of the center of gravity of the plastic bottle makes sense in terms of weight balance. Yes. However, when the contents are poured out, the operability of the position of the mouth is better when the outer surface closer to the mouth is gripped. In Patent Document 1, there is no description or suggestion about gripping the outer surface portion, and there is a reinforcing groove for increasing the rigidity, etc. that affects the ease of holding the outer surface portion. There is no particular description other than being formed. In particular, Patent Document 1 has no description or suggestion about the ease of holding the outer surface portion of a plastic bottle that is reduced in thickness and reduced in weight. Furthermore, the plastic bottle of Patent Document 1 has a weak buckling strength against a load in the vertical direction in which the outer surface portion extends.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a square plastic bottle and a filling body that have rigidity and are not easily crushed and are lightweight and excellent in ease of holding.

  In order to solve the above-described problems, the present invention sequentially includes a mouth portion, a shoulder portion, a trunk portion, and a bottom portion in the axial direction, and the trunk portion includes a plurality of planar portions and the planar portion adjacent in the circumferential direction. In the plastic bottle having a square tube portion composed of connecting corner portions, the square tube portion has a groove that circulates the plastic bottle, the groove has a constant width over the entire circumference, and the flat surface. The central portion of the portion has a smaller depth than that of the peripheral portion of the flat portion.

  Furthermore, the groove has a smaller depth at the corner portion than at the central portion.

  Further, the groove is characterized in that the ratio of the depth at the central portion to the depth at the peripheral portion is 0.45 or more and 0.95 or less.

  Furthermore, the distance between the adjacent grooves is constant over the entire circumference.

  Furthermore, the groove has a curved shape in the cross section in the axial direction.

  Furthermore, the internal volume of the plastic bottle is 680 ml or more and 2500 ml or less.

  Furthermore, the ratio of the mass to the volume of the plastic bottle is 0.0105 g / ml or more and 0.0300 g / ml or less.

  Furthermore, the filling body according to the present invention is constituted by the plastic bottle described above and a liquid to be filled.

  According to the present invention, a rectangular tube having a mouth portion, a shoulder portion, a trunk portion, and a bottom portion in the axial direction sequentially, the trunk portion including a plurality of plane portions and a corner portion connecting the plane portions adjacent in the circumferential direction. In the plastic bottle having a portion, the square tube portion has a groove that circulates the plastic bottle, the groove has a constant width over the entire circumference, and the peripheral portion of the flat portion at the central portion of the flat portion. Therefore, it is possible to provide a square-shaped plastic bottle that is hard to be crushed while having rigidity and excellent in ease of holding while having light weight.

  Furthermore, according to the configuration in which the groove has a smaller depth in the corner portion than in the center portion, the strength of the corner portion can be increased and the strength of the plastic bottle can be further increased.

  Furthermore, according to the configuration in which the value of the ratio of the depth at the central portion to the depth at the peripheral portion is 0.45 or more and 0.95 or less, the groove is particularly flat against the radial load. This makes it difficult to bend the central part of the plastic bottle, making it more difficult to crush the plastic bottle.

  Furthermore, according to the configuration in which the distance between adjacent grooves is constant over the entire circumference, in particular, the radial load can be more evenly distributed and the plastic bottle can be made more difficult to collapse.

  Furthermore, according to the configuration in which the groove has a curved shape in the cross section in the axial direction, the groove can be made difficult to bend particularly with respect to the load in the axial direction, and the strength of the plastic bottle can be further increased.

  Furthermore, according to the configuration in which the internal volume of the plastic bottle is 680 ml or more and 2500 ml or less, it is possible to provide a particularly large and square plastic bottle that has rigidity but is difficult to be crushed and is easy to hold. .

  Further, according to the configuration in which the value of the ratio of the mass to the volume of the plastic bottle is 0.0105 g / ml or more and 0.0300 g / ml or less, it is hard to be crushed while having rigidity, and it is excellent in ease of holding. A square plastic bottle having lightness can be provided.

  Furthermore, since the filling body according to the present invention is composed of the above-described plastic bottle and the liquid to be filled, it is a square shape that has rigidity and is not easily crushed, has lightweight properties, and is easy to hold. A filling body in which a plastic bottle is used can be provided.

It is the front view by which the PET bottle as an example of the plastic bottle which concerns on this embodiment was shown. It is a top view of a PET bottle. It is the front view to which the circumferential groove was expanded. It is the IV-IV sectional view taken on the line of FIG. It is a bottom view of a PET bottle. 6 is a cross-sectional view of a peripheral groove of PET bottles of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of the plastic bottle according to the present embodiment will be described in detail. FIG. 1 is a front view showing a PET bottle 1 as an example of a plastic bottle according to the present embodiment, and FIG. 2 is a top view of the PET bottle 1. The PET bottle 1 is a so-called square bottle having a substantially rectangular tube shape. The PET bottle 1 is formed by stretching a resin in the form of a test tube called a preform, which is a prototype of the PET bottle 1. The PET bottle 1 has a mouth part 10, a shoulder part 20, a trunk part 30, and a bottom part 40 in that order in the axial direction. And the trunk | drum 30 has the square cylinder part which consists of the corner part 32 which connects the several plane part 31 and the plane part 31 which adjoins the circumferential direction of the PET bottle 1 in the circumferential direction.

  In the following, for convenience of explanation, the mouth portion 10 in which the contents are filled into the container in the state of FIG. 1 that is upright so that the axial direction of the PET bottle 1 extends vertically will be referred to as the top. The PET bottle 1 has an overall height H1 from the bottom 40 to the mouth 10.

  The PET bottle 1 may be a square bottle having a square tube portion. The PET bottle 1 illustrated in FIG. 2 and the like has a substantially square cross section of a rectangular tube portion orthogonal to the axial direction. However, in this case, the square bottle may have a substantially regular polygonal cross section, for example, a substantially regular dodecagon, and each of the plurality of planar portions 31 has a different circumferential length. For example, it may be a rectangle.

  The mouth portion 10 serves as a filling port and a spout for the contents, and the PET bottle 1 is sealed by attaching a lid (not shown) to the mouth portion 10. The mouth portion 10 may be crystallized until it is colored white by heating in a so-called crystallization apparatus so as to have heat resistance necessary for filling the contents at high temperature.

  The upper side of the shoulder portion 20 is continuous with the mouth portion 10, while the lower side is continuous with the trunk portion 30. The shoulder 20 is configured in a truncated pyramid shape that extends in the radial direction of the PET bottle 1 from the upper side to the lower side in the axial direction.

  The PET bottle 1 has a ridge line 21 extending in the circumferential direction between the shoulder portion 20 and the trunk portion 30. The ridge line 21 has a function of absorbing the axial load of the PET bottle 1. The ridge line 21 undulates in the axial direction, and is located closest to the trunk portion 30 in the corner portion 32. If the shoulder portion 20 in the region above the corner portion 32 is left as it is, it is easy to bend due to the axial load. However, the ridgeline 21 is dispersed without being concentrated at a portion where the ridgeline 21 is easily bent at the corner portion 32 due to the configuration located closest to the body portion 30, and the buckling strength of the PET bottle 1 is increased.

  The shoulder 20 is formed with a plurality of flat cut surfaces. And the side which becomes the boundary of these cut surfaces mainly functions as a support | pillar with respect to the load of the axial direction of the PET bottle 1 by extending in an axial direction.

  On the flat portion 31, an isosceles triangular region that is long in the axial direction with the ridge line 21 as a base is formed by a ridge line 22 that protrudes toward the outside of the PET bottle 1. Further, inside the isosceles triangle region, three triangular panels are formed by the three ridge lines 23 protruding toward the inside of the PET bottle 1. By configuring the shoulder 20 in the region above the flat portion 31 in this way, the strength against the axial and radial loads of the PET bottle 1 is increased, and the pressure inside the PET bottle 1 is changed. In some cases, the shape is maintained without being deformed.

  Furthermore, the shoulder portion 20 has a ridge line 24 that protrudes toward the outside of the PET bottle 1 and extends in the axial direction starting from the circumferential center of the corner portion 32. The ridge line 24 is easily recessed inside the PET bottle 1 when pressed. Furthermore, a ridge line 25 protruding toward the outside of the PET bottle 1 is also formed between the mouth 10 side of the ridge line 24 and the boundary between the flat surface portion 31 and the corner portion 32 of the ridge line 21. Accordingly, a fan-shaped sink panel 26 having a ridge line 24 that bisects the central angle is formed on the shoulder 20 in the region above the corner portion 32. The ridge line 25 prevents the deformation when the ridge line 24 is pressed from spreading to a region outside the fan shape.

  The body 30 is packaged with a label such as a shrink label or a roll label on which information on the contents of the PET bottle 1 or a pattern for improving the design is printed. A biaxially stretched polystyrene film or the like having good heat shrinkability is used for the shrink label attached by heat shrinkage. Since the shrink label is made of a material different from that of the PET bottle 1, it is separated when it is recycled after the PET bottle 1 is used. Since the shrink label is mainly attached to the corner portion 32, the shrink label is easily removed by removing the catch at the corner portion 32. When the ridge line 24 is pushed, a gap is formed between the PET bottle 1 and the label in the vicinity of the corner portion 32 so that the label can be easily grasped, and the catch of the corner portion 32 is partially removed, and the label is easily peeled off. be able to.

  A plurality of cut surfaces formed in the shoulder portion 20 illustrated in FIG. 1 and the like are formed in a flat plate shape, and are not curved outside or inside the PET bottle 1. However, if the shoulder portion 20, particularly the fan-shaped sinking panel 26 is configured to be curved outwardly of the PET bottle 1, a wider gap is formed between the PET bottle 1 and the label, making the label easier. Can be peeled off.

  Although the shoulder 20 is not limited to the above-described configuration, it is preferable that the shoulder 20 has a ridge line 21 and a ridge line 24 in terms of the strength and shape maintaining function of the PET bottle 1 and the ease of peeling off the label.

  The trunk | drum 30 has the upper side square cylinder part 50 as a square cylinder part. The upper rectangular tube portion 50 illustrated in FIG. 2 and the like has four plane portions 31 and four corner portions 32 having the same shape. The length of the planar portion 31 in the circumferential direction is 31.6 mm, for example.

  The corner portion 32 is curved outward in the radial direction. The upper rectangular tube portion 50 has the same radial dimension in the upper and lower sides, and has a substantially regular rectangular tube shape as a whole. The upper rectangular tube portion 50 has a shape close to a cylinder by having the corner portion 32 curved outward, and the buckling strength is improved. There is no particular limitation on the radius of curvature of the corner portion 32. The corner portion 32 has a curvature radius of 19 mm, for example.

  The upper rectangular tube portion 50 is configured to have a diagonal distance D1 and a facing distance D2. The diagonal distance D1 is larger than the facing distance D2. The diagonal distance D1 is set to 82.5 mm, for example, and the facing distance D2 is set to 69.4 mm, for example.

  FIG. 3 is a front view in which the circumferential groove 51 is enlarged. The upper rectangular tube portion 50 has a plurality of annular circumferential grooves 51 that are recessed inward in the radial direction and cross the planar portion 31 and the corner portion 32 in the circumferential direction. The circumferential groove 51 has a function of increasing the side wall strength, which is the strength that can withstand the load in the radial direction. Furthermore, the circumferential groove 51 functions as a cushion against an axial load and has a function of preventing the body portion 30 from buckling. When the side wall strength of the upper rectangular tube portion 50 is increased, a moderate repulsive force is generated when the upper rectangular tube portion 50 is gripped, and the ease of holding the PET bottle 1 is improved. Furthermore, the ease of attaching the label to the upper rectangular tube portion 50 is improved by increasing the side wall strength of the upper rectangular tube portion 50.

  The circumferential groove 51 may have a substantially tapered or V-shaped cross section in the axial direction having a flat bottom surface. However, it is preferable that the circumferential groove 51 has a curved shape such as an arc shape in an axial section, and has no corners. The PET bottle 1 is not bent with respect to the axial load due to the configuration in which the axial section of the circumferential groove 51 does not have an angle, and the buckling strength is further increased.

  The circumferential groove 51 has different dimensions in the central portion 31m and in the peripheral portion 31p in the plane portion 31. Further, the circumferential groove 51 may be configured to have different dimensions in the plane portion 31 and in the corner portion 32.

  Here, the boundary between the central portion 31m and the peripheral portion 31p does not need to be strictly defined, and the size of the circumferential groove 51 is different between the vicinity of the center of the plane portion 31 in the circumferential direction and the vicinity of the center. It is sufficient if the PET bottle 1 is configured with such a tendency. The boundary between the central portion 31m and the peripheral portion 31p may be based on, for example, an area where the flat portion 31 is equally divided into three in the circumferential direction.

  FIG. 3 shows a central portion width Wm that is a width in the central portion 31m of the circumferential groove 51, a peripheral portion width Wp that is a width in the peripheral portion 31p, and a corner portion width Wc that is a width in the corner portion 32. . The circumferential groove 51 has a certain width over the entire circumference. That is, the central portion width Wm, the peripheral portion width Wp, and the corner portion width Wc of the circumferential groove 51 are all equal.

  If the width of the circumferential groove 51 is too large, the strength against the axial load is reduced and the amount of compressive deformation is increased. On the other hand, when the width of the circumferential groove 51 is too small, the shapeability of the body portion 30 is not good. Therefore, the width of the circumferential groove 51 is appropriately designed as long as the shapeability is good and the strength against the axial load is ensured. The central part width Wm, the peripheral part width Wp, and the corner part width Wc are, for example, 3.2 mm.

  4 is a cross-sectional view taken along line IV-IV in FIG. That is, FIG. 4 shows a surface in which the upper rectangular tube portion 50 is cut at the center in the axial direction of the circumferential groove 51 in a direction orthogonal to the axial direction. The peripheral groove 51 has a substantially rounded square cross section on the outer periphery, a central portion depth Dm that is a depth in the central portion 31m, a peripheral portion depth Dp that is a depth in the peripheral portion 31p, and a corner portion 32. It has a corner portion depth Dc which is the depth at.

  The circumferential groove 51 has a smaller depth in the central portion 31 m of the flat surface portion 31 than in the peripheral portion 31 p of the flat surface portion 31. That is, the central part depth Dm of the circumferential groove 51 is smaller than the peripheral part depth Dp. The circumferential groove 51 has a function of increasing the rigidity of the body portion 30 even in the PET bottle 1 which is configured to have a larger peripheral portion depth Dp and thus reduced in thickness and reduced in weight. On the other hand, the circumferential groove 51 gives flexibility to the central part 31m of the flat part 31 by being configured to have a smaller central part depth Dm, so that the flat part 31 of the PET bottle 1 is from the radially outer side. It has a function to prevent crushing without bending even if it receives the force of. The central portion depth Dm is, for example, 1.5 mm, and the peripheral portion depth Dp is, for example, 2.1 mm. And the circumferential groove 51 which has a different depth in the plane part 31 is comprised so that the smooth curve which the depth may change continuously may be drawn in the circumferential direction.

  If the difference between the central portion depth Dm and the peripheral portion depth Dp is too small, the above-described effects will not be exhibited. On the other hand, if the central portion depth Dm is too small with respect to the peripheral portion depth Dp, the strength against the load in the axial direction is reduced, and the peripheral portion 31p is easily crushed or the central portion 31m is too soft. As a result, the ease of holding is reduced. These phenomena become more severe as the body 30 is made thinner in order to reduce the weight of the PET bottle 1. Therefore, it is preferable that the circumferential groove 51 has a ratio of the central portion depth Dm to the peripheral portion depth Dp of 0.45 or more and 0.95 or less. By configuring the circumferential groove 51 in this way, the central portion 31m of the flat surface portion 31 is made difficult to bend particularly with respect to the radial load while increasing the rigidity of the peripheral portion 31p, and the PET bottle 1 is more It can be made difficult to be crushed.

  Thus, the circumferential groove 51 has a constant width over the entire circumference, and has a smaller depth in the central portion 31 m of the flat surface portion 31 than in the peripheral portion 31 p of the flat surface portion 31. By being configured in this way, the PET bottle 1 is not easily crushed while having rigidity, and excellent ease of holding is realized while having light weight.

  The circumferential groove 51 preferably has a smaller depth at the corner portion 32 than at the central portion 31m. That is, the corner portion depth Dc of the circumferential groove 51 is preferably smaller than the center portion depth Dm.

  The circumferential groove 51 configured as described above has a function of making the corner portion 32 difficult to bend with respect to an axial load while remaining rigid. That is, the circumferential groove 51 can increase the strength of the corner portion 32 and increase the strength of the PET bottle 1 particularly with respect to the axial load. Furthermore, since the circumferential groove 51 increases the side wall strength in the flat surface portion 31, the PET bottle 1 can be stably loaded sideways. Furthermore, since the circumferential groove 51 has a small depth at the corner portion 32 having a distance from the radial center of the PET bottle 1 in the radial direction, the circumferential groove 51 does not have an uneven shape and has good shapeability. is there.

  In the corner portion 32, a circumferential groove 51 is formed so as to have a minimum depth at the center in the circumferential direction. The circumferential groove 51 having different depths in the corner portion 32 and the flat portion 31 is configured to draw a smooth curve in the circumferential direction in which the depth continuously changes. The corner depth Dc is set to, for example, 0.9 mm.

  The circumferential groove 51 is designed with a width based on the peripheral portion 31p of the flat surface portion 31 where the depth is the maximum, so that the body portion 30 does not have a concavo-convex shape and has good shapeability. Can be.

  The upper rectangular tube portion 50 of the PET bottle 1 illustrated in FIG. 1 and the like has six circumferential grooves 51. Here, it is preferable that the distance between adjacent circumferential grooves 51 is constant over the entire circumference. Particularly, each of the plurality of circumferential grooves 51 configured in this manner can disperse the load in the radial direction more evenly and can make the PET bottle 1 more difficult to be crushed. For this reason, as illustrated in FIG. 1 and the like, the six circumferential grooves 51 are preferably configured to have the same depth and width dimensions, and are arranged in parallel and at equal intervals. .

  In addition, when the upper side square cylinder part 50 of PET bottle 1 has sufficient thickness, it can also be set as the structure where the circumferential groove 51 is extended diagonally with respect to an axial direction.

  As described above, the upper rectangular tube portion 50 in which the plurality of circumferential grooves 51 are relatively simply formed has a flat area on a surface thereof with a large area, so that unevenness can be suppressed. For this reason, it becomes easy to attach the label to the upper rectangular tube portion 50, and it is difficult to cause an appearance defect when the label is attached, thereby improving the production efficiency of the PET bottle 1 and the display effect (advertisement effect) by the label. Can do.

  Note that FIG. 1 and the like show an example in which six circumferential grooves 51 are formed in the upper rectangular tube portion 50. However, the number is not particularly limited, and the number is appropriately designed according to the axial length of the upper rectangular tube portion 50, the depth and width of the circumferential groove 51, and the like. Further, the depth of all the circumferential grooves 51 is not designed to be the same, but the upper side, for example, the two circumferential grooves 51, particularly the depth at the peripheral portion 31 p, is smaller than the depth of the lower circumferential groove 51. It may be said. By being configured in this way, it is possible to disperse the stress concentration in the upper circumferential groove 51 that is likely to be deformed with respect to an axial load.

  When the square bottle is long in the axial direction, the side wall strength is increased by increasing the number of the circumferential grooves 51. However, as the number of the circumferential grooves 51 increases, the amount of compressive deformation due to the axial load increases. Therefore, the PET bottle 1 is configured to have a cylindrical portion 60 having a circular cross section perpendicular to the axial direction in order to further suppress the amount of compressive deformation with respect to the load in the axial direction and further strengthen the buckling strength. Also good. In that case, it is preferable that the cylindrical portion 60 has both ease of holding and strength. There is a PET bottle 1 that can be selectively used such that the cylindrical portion 60 is gripped when opening a cap (not shown) of the PET bottle 1 and the upper rectangular tube portion 50 is gripped when dispensing the contents. It may be configured.

  The cylindrical portion 60 has a constricted portion 61. The neck portion 61 is formed by narrowing the body portion 30 in the radial direction. The constricted portion 61 can effectively increase the buckling strength. Furthermore, the constricted portion 61 is easy to grip because the waistline is short. Therefore, the constricted portion 61 also functions as a gripping portion, and can easily hold the PET bottle 1.

  The constricted portion 61 has a rib 62 extending in the axial direction. The rib 62 protrudes outward in the radial direction of the PET bottle 1. The rib 62 has a function as a support for both the axial and radial loads of the PET bottle 1. A plurality of ribs 62 are arranged in the circumferential direction of the constricted portion 61. The constricted part 61 in which the plurality of ribs 62 are arranged is improved in strength and hardly deformed, and the PET bottle 1 can be easily held. Further, the rib 62 can be applied to the grasped finger and can easily hold the PET bottle 1.

  As illustrated in FIG. 1 and the like, the rib 62 has a twist in the circumferential direction. Since the rib 62 has a twist, it becomes easier to catch the finger gripped, and the PET bottle 1 becomes easier to hold. Furthermore, since the rib 62 has a twist, the axial load is dispersed in the circumferential direction, and the buckling strength of the PET bottle 1 can be increased. For example, the rib 62 is inclined at 45 degrees with respect to the vertical line.

  At the upper end of the constricted portion 61, adjacent ribs 62 are connected by an upper side 63. The upper side 63 is curved in an arc shape toward the upper side. Similarly, adjacent ribs 62 are connected by a lower side 64 at the lower end of the constricted portion 61. The lower side 64 is curved in an arc shape toward the lower side. By forming the upper side 63 and the lower side 64, the cylindrical portion 60 is not easily deformed, and the PET bottle 1 can be easily held. Furthermore, the curved upper side 63 and the lower side 64 can absorb the axial load of the PET bottle 1 and increase the buckling strength. Two adjacent ribs 62 are taken as opposite sides, and an oblong panel 65 is formed by the opposite sides, the upper side 63, and the lower side 64. Therefore, the constricted portion 61 is formed in a cylindrical shape by connecting a plurality of panels 65 curved radially inward in the circumferential direction.

  In addition, the area | region above the upper side 63 and the area | region below the lower side 64 are the cylindrical shapes of the same diameter up and down. Although there is no restriction on the size relationship between this cylinder and the upper rectangular tube portion 50 in the radial direction of the PET bottle 1, the cylindrical portion 60 is an inscribed circle of the upper rectangular tube portion 50 from the viewpoint of the loading efficiency of the PET bottle 1 and the like. It is preferable that

  The panel 65 including the ribs 62 has a curved shape so that the diameter decreases toward the center in the axial direction starting from the upper side 63 and the lower side 64. And the rib 62 is comprised so that the distance from the center of radial direction may become the maximum in the arbitrary cross sections orthogonal to the axial direction of the constriction part 61. FIG. That is, the cross section of the outer periphery of the constricted portion 61 is a polygon having the rib 62 as a vertex. The PET bottle 1 configured in this manner has both lightness and high strength against external force, and is easy to hold.

  The number of the panels 65 may be appropriately designed from the viewpoint of improving ease of holding while maintaining the strength of the PET bottle 1. The panel 65 of the PET bottle 1 illustrated in FIG. 1 and the like is composed of six pieces having the same shape.

  The length in the axial direction of the constricted portion 61 may be designed from the viewpoint of maintaining strength while having the ease of holding the PET bottle 1, and is preferably at least longer than the width of the first finger. For example, the first finger and the third finger used for gripping are constricted in the configuration of the rib 62 having a twist in the circumferential direction, the rib 62 having a curved shape, and the panel 65. The PET bottle 1 is easy to hold in line with the portion 61. The length of the cylindrical portion 60 in the axial direction is not necessarily limited to the second finger and the fourth finger along the third finger, and is, for example, 38.5 mm.

  FIG. 5 is a bottom view of the PET bottle 1. When the trunk portion 30 is configured to include the cylindrical portion 60, it is preferable to have the lower rectangular tube portion 70 including the planar portion 31 and the corner portion 32, similarly to the upper rectangular tube portion 50. Then, since the facing distance D2 of the upper corner tube portion 50 and the lower corner tube portion 70 is formed to be the same, each flat surface portion 31 of the upper corner tube portion 50 and the lower corner tube portion 70 becomes the ground contact portion. Thus, the PET bottle 1 can be stably placed in a horizontal state in which the axial direction is horizontal. Furthermore, the facing distance D2 of the upper corner tube portion 50 and the lower corner tube portion 70 is formed to be the same so that a plurality of PET bottles 1 can be stably stored when being boxed.

  Two circumferential grooves 71 are formed in the lower rectangular tube portion 70 exemplified in FIG. The lower rectangular tube portion 70 is not often gripped and is required for rigidity, but the importance of ease of holding is not as high as that of the upper rectangular tube portion 50. Therefore, the circumferential groove 71 of the lower rectangular tube portion 70 does not necessarily have the configuration having the characteristics of the circumferential groove 51. That is, the central part depth Dm of the circumferential groove 71 may not be smaller than the peripheral part depth Dp. However, it is preferable that the lower rectangular tube portion 70 is provided with the peripheral groove 71 having the same configuration as the peripheral groove 51, so that rigidity and difficulty in crushing can be imparted. For this reason, the lower rectangular tube portion 70 may have the same configuration as the upper rectangular tube portion 50. By being configured in this way, for example, when the PET bottle 1 is grasped with both hands, the lower square tube portion 70 is prevented from being crushed by the attached hands and is easy to hold.

  The PET bottle 1 is formed to have a lower height H2 from the bottom 40 to the lower end of the upper rectangular tube 50. If the ratio of the lower height H2 to the total height H1 (H2 / H1) is too small, the cylindrical portion 60 and the lower rectangular tube portion 70 cannot be formed below the upper rectangular tube portion 50. Depending on the capacity (height) of the PET bottle 1, it is difficult to maintain the strength. On the other hand, if H2 / H1 is too large, the upper rectangular tube portion 50 becomes small and the area for displaying the label becomes narrow. Furthermore, when the area of the upper rectangular tube portion 50 is narrowed, the location where the PET bottle 1 is gripped is limited, and the operability is degraded. Therefore, the PET bottle 1 preferably has a ratio value (H2 / H1) of the lower height H2 to the total height H1 of 0.20 or more and 0.49 or less. The value (H2 / H1) of the ratio of the lower height H2 to the total height H1 is, for example, 0.39.

  Since the upper rectangular tube portion 50 has rigidity and is not easily crushed and has excellent lightness, it can be extended to the lower side of the center of gravity of the PET bottle 1. Therefore, the PET bottle 1 can use the upper rectangular tube portion 50 as a gripping portion in a wide range and can take a large area for attaching the label.

  It is preferable that the upper rectangular tube portion 50, the lower rectangular tube portion 70, and the cylindrical portion 60 are connected to each other via a connecting groove 80 and a connecting groove 85 that are recessed in the radial direction and extend in the circumferential direction. The connecting groove 80 and the connecting groove 85 have a function of receiving an axial load as a cushion and preventing bending of the connecting portion. Further, the connecting groove 80 and the connecting groove 85 have a function of increasing the side wall strength in the vicinity of the connecting portion. The connecting groove 80 and the connecting groove 85 have a circular cross section perpendicular to the axial direction and a substantially tapered shape having a flat bottom surface in the axial direction. The connecting groove 80 and the connecting groove 85 may have a vertical cross section of an arc shape or a V shape.

  If the depth of the connecting groove 80 and the connecting groove 85 is too shallow, it becomes difficult to increase the buckling strength. On the other hand, if the depth of the connecting groove 80 and the connecting groove 85 is too deep, the shapeability at the time of molding the PET bottle 1 tends to be lowered. The depth of the connecting groove 80 and the connecting groove 85 is preferably such that the ratio of the outer diameter of the cylindrical portion 60 to the maximum portion is 0.005 or more and 0.07 or less, more preferably 0.03. preferable.

  If the width of the connecting groove 80 and the connecting groove 85 is too wide, it is difficult to increase the side wall strength. On the other hand, when the width of the connecting groove 80 and the connecting groove 85 is too narrow, the shapeability at the time of molding of the PET bottle 1 tends to be lowered. The width of the connecting groove 80 and the connecting groove 85 is preferably such that the value of the ratio to the depth of the connecting groove 80 and the connecting groove 85 is not less than 0.5 and not more than 5.0.

  A chamfered portion 52 may be formed at the corner portion 32 of the upper rectangular tube portion 50 that is in contact with the upper end of the connecting groove 80. Similarly, a chamfered portion 72 may also be formed at the corner portion 32 of the lower rectangular tube portion 70 that is in contact with the lower end of the connecting groove 85. Furthermore, a chamfered portion 73 may also be formed in the corner portion 32 at the lower end of the lower rectangular tube portion 70. By forming the chamfered portion 52, the chamfered portion 72, and the chamfered portion 73, the axial load is dispersed without concentrating on the corner portion 32 that is easily bent, and the buckling strength of the PET bottle 1 is increased.

  The bottom portion 40 continues to the lower side of the lower rectangular tube portion 70 of the trunk portion 30. The bottom portion 40 has a corner portion 41, a bottom wall 42, and a dome 43. The corner portion 41 is curved toward the lower side in the axial direction of the PET bottle 1 and the outer side in the radial direction. The substantially flat annular bottom wall 42 extends in a direction perpendicular to the body portion 30 and serves as a ground contact surface of the PET bottle 1.

  The dome 43 is formed in a hollow hemispherical shape that curves toward the inside (the upper side in the axial direction) of the PET bottle 1. The dome 43 has a function of preventing deformation due to changes in the temperature of the contents of the PET bottle 1 and the internal pressure. The dome 43 only needs to be designed to have an inclination angle with respect to the ground plane within a range in which the pressure and the like are effectively dispersed to prevent deformation and the shapeability is good. As illustrated in FIG. 1 and the like, the dome 43 may be configured to protrude in a plurality of stages toward the upper side in the axial direction on the inner side in the radial direction.

  The dome 43 illustrated in FIG. 5 has eight radial ribs 44 and eight circumferential ribs 45. Each of the radial ribs 44 extends radially in a bottom view. The circumferential rib 45 extends circumferentially between adjacent radial ribs 44 in a bottom view. The radial ribs 44 are formed so as to protrude toward the upper side in the axial direction from the dome 43. On the contrary, the circumferential rib 45 is formed so as to protrude toward the lower side in the axial direction than the dome 43. Both the radial rib 44 and the circumferential rib 45 have a function of reinforcing the dome 43. The radial ribs 44 and the circumferential ribs 45 may be formed so as to protrude within a range where whitening due to overstretching and deterioration of the shapeability of the PET bottle 1 do not occur.

  A concave receiving portion 46 may be formed at the center in the radial direction of the bottom portion 40, that is, at the top of the dome 43. The receiving portion 46 is configured such that the end of the stretching rod enters when the PET bottle 1 is stretched and molded from a preform that is a prototype. The receiving portion 46 has a function of preventing the bottom portion 40 from being eccentric in the radial direction by the extending rod.

  Note that the bottom 40 is not limited to the example shown in FIG. 5 and the like, and may be configured so as not to be deformed downward even when positive pressure is applied in a state where it is easily deformed by heat. As a result, the full capacity of the PET bottle 1 is increased from the design value, and it is possible to prevent the change in the internal pressure from becoming larger due to the increase in the proportion of air in the container. The dome 43 is designed to be maintained at least higher than the ground plane of the PET bottle 1 even if it is deformed by heat. Thus, the bottom portion 40 is prevented from projecting outward (downward) from the bottom wall 42, and rattling or overturning of the PET bottle 1 can be prevented.

  The PET bottle 1 according to this embodiment is not limited by size, and can be applied to various sizes. However, it is preferable that the bottle is larger because the effect of the configuration of the PET bottle 1 according to this embodiment is more exhibited. For example, the internal volume of the PET bottle 1 is preferably 680 ml or more and 2500 ml or less, and more preferably 850 ml to 2000 ml. The total height H1 of the PET bottle 1 may be 190 mm or more and 320 mm or less, and the facing distance D2 of the body part 30 may be 60 mm or more and 100 mm or less.

  Furthermore, the PET bottle 1 according to the present embodiment can be suitably used for light weight bottles. And, in particular, from the viewpoint of maintaining the strength of the PET bottle 1 while having lightness and increasing the amount of absorption of the change in internal pressure, the value of the ratio of the mass to the internal volume of the PET bottle 1 is 0.0105 g / ml or more, It is preferable that it is 0.0300 g / ml or less.

  Examples of the material of the plastic bottle exemplified by the PET bottle 1 include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, and other polyolefins, ethylene-vinyl alcohol copolymers, plants, and the like. Various plastics that can be blow molded, such as polylactic acid, can be used. However, the plastic bottle is preferably composed mainly of polyester such as polyethylene naphthalate, particularly polyethylene terephthalate. In addition, various additives such as a colorant, an ultraviolet absorber, a release agent, a lubricant, a nucleating agent, an antioxidant, and an antistatic agent are blended with the above-described resin within a range that does not impair the quality of the molded product. be able to.

  As the ethylene terephthalate thermoplastic resin constituting the PET bottle 1, most of the ester repeating portion, generally 70 mol% or more is occupied by ethylene terephthalate units, and the glass transition point (Tg) is 50 ° C. or higher and 90 ° C. The melting point (Tm) is preferably in the range of 200 ° C. or higher and 275 ° C. or lower. As an ethylene terephthalate thermoplastic polyester, polyethylene terephthalate is particularly excellent in terms of pressure resistance, but in addition to ethylene terephthalate units, it consists of dibasic acids such as isophthalic acid and naphthalenedicarboxylic acid, and diols such as propylene glycol. Copolyesters containing a small amount of ester units can also be used.

  Polyethylene terephthalate has the highest production volume among thermoplastic synthetic resins. The polyethylene terephthalate resin has various characteristics such as excellent heat resistance, cold resistance, chemical resistance, and wear resistance. Furthermore, polyethylene terephthalate resin has a lower proportion of petroleum in its raw materials than other plastics, and can be recycled. Thus, according to the structure which has a polyethylene terephthalate as a main component, a material with much production amount can be used and the outstanding various characteristic can be utilized.

  Polyethylene terephthalate is obtained by condensation polymerization of ethylene glycol (ethane-1,2-diol) and purified terephthalic acid. As a polymerization catalyst for polyethylene terephthalate, at least one of a germanium compound, a titanium compound, and an aluminum compound is preferably used. By using these catalysts, it is possible to form a container having higher transparency and excellent heat resistance than using an antimony compound.

  A plastic bottle can be produced by blow-molding a preform in which the above-described material is injection-molded. And PET bottle 1 as an example of the plastic bottle which concerns on this embodiment is produced by using a polyethylene terephthalate as a material. And the filling body is comprised by the PET bottle 1 and the liquid with which it fills. The filling body is manufactured by filling a liquid such as a beverage or a seasoning from the mouth portion 10 of the PET bottle 1 and sealing with a lid (not shown) attached to the mouth portion 10.

  As described above, the PET bottle 1 has the mouth portion 10, the shoulder portion 20, the trunk portion 30, and the bottom portion 40 sequentially in the axial direction, and the trunk portion 30 is adjacent to the plurality of plane portions 31 and the circumferential direction. It has an upper rectangular tube portion 50 composed of a corner portion 32 connecting the flat surface portion 31, and the upper rectangular tube portion 50 has a circumferential groove 51 that goes around the PET bottle 1, and the circumferential groove 51 is constant over the entire circumference. And the depth of the central portion 31m of the flat surface portion 31 is smaller than that of the peripheral portion 31p of the flat surface portion 31. According to such a configuration, it is possible to provide a square PET bottle 1 that has rigidity and is not easily crushed and has excellent lightness and ease of holding.

  Furthermore, the filling body is constituted by a PET bottle 1 and a liquid to be filled. According to such a configuration, it is possible to provide a filling body using the square PET bottle 1 having rigidity and being hard to be crushed and having excellent lightness and being easy to hold.

  Note that the PET bottle 1 and the filling body according to the present embodiment may have different configurations from those described above except for the circumferential groove 51 formed in the upper rectangular tube portion 50 as the rectangular tube portion. .

  Hereinafter, the present disclosure will be described in more detail and specifically with reference to examples. However, the present disclosure is not limited to the following examples.

<Material and manufacturing method>
[Example 1]
The PET bottle 1 shown in FIG. The central depth Dm of the PET bottle 1 was 1.5 mm, and the peripheral depth Dp was 2.1 mm. The PET bottle 1 was filled with 900 ml of water and then closed with a cap (not shown) to produce a filled body.

  The PET bottle 1 and the filler according to Example 1 have a circumferential groove 51 that circulates the PET bottle 1 in the upper rectangular tube portion 50, and the circumferential groove 51 has a constant width over the entire circumference. In addition, the central portion 31m of the flat surface portion 31 has characteristics according to the present embodiment, such as having a smaller depth than the peripheral portion 31p of the flat surface portion 31.

[Comparative Example 1]
6 is a cross-sectional view of the circumferential groove 251 of the PET bottle 200 corresponding to FIG. 3 of the first embodiment. Comparative Example 1 was the same as Example 1 except that the PET bottle 200 having the circumferential groove 251 shown in FIG. A circumferential groove 251 that circulates the PET bottle 200 was formed in the upper rectangular tube portion 250 of the body portion 230 of the PET bottle 200. However, the circumferential groove 251 has the same depth both in the central portion 231m of the flat surface portion 231 and in the peripheral portion 231p of the flat surface portion 231. In the PET bottle 200 of Comparative Example 1, the depth of the circumferential groove 251 was 2.1 mm, which is the same as the peripheral portion depth Dp in the PET bottle 1 of Example 1. Therefore, the filler according to Comparative Example 1 did not have the characteristics according to the present embodiment.

[Comparative Example 2]
Comparative Example 2 was the same as Comparative Example 1 except that it was 28 g. Therefore, the filler according to Comparative Example 2 also did not have the characteristics according to this embodiment.

[Comparative Example 3]
Comparative Example 3 was the same as Comparative Example 1 except that the depth of the circumferential groove 251 was 1.5 mm, which was the same as the central portion depth Dm in the PET bottle 1 of Example 1. Therefore, the filler according to Comparative Example 3 also did not have the characteristics according to this embodiment.

[Comparative Example 4]
Comparative Example 4 was the same as Comparative Example 3 except that it was 28 g. Therefore, the filler according to Comparative Example 4 also did not have the characteristics according to the present embodiment.

<Evaluation method>
(Lightweight)
It was determined whether weight reduction could be achieved by the mass of each PET bottle of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. In the determination of weight reduction, a threshold value was set to be greater than 24 g or less. Table 1 shows the results of evaluation of the lightness of each PET bottle, and is indicated by ◯: light weight and x: no light weight.

(Side wall strength test)
The side wall strength of the upper rectangular tube portion 50 and the upper rectangular tube portion 250 in the state in which the fillers of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are placed horizontally is shown. Measured. For measuring the side wall strength, a tester manufactured by AGR, TOP LOAD, was used. A load was applied at a constant speed from above the central portion 31m of the flat surface portion 31 and the central portion 231m of the flat surface portion 231, and the load at the stage of displacement by 5 mm was set as the side wall strength. In the determination of the side wall strength, 40 N or more or less was set as a threshold. Table 1 shows the results of evaluation of the side wall strength of each filler, and is indicated by ◯: With side wall strength, x: Insufficient side wall strength.

(Monitoring survey)
Each filling body of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 is prepared. The contents were poured out after holding the flat surface portion 231 of the upper rectangular tube portion 250. At that time, those that did not collapse were counted as one point. Table 1 shows the total score.

(Comprehensive evaluation)
Based on the above-described lightness, side wall strength test, and monitoring survey, comprehensive evaluation of each PET bottle (each filler) of Example 1 and Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 It has been made. Table 1 shows the results of comprehensive evaluation. Comprehensive evaluation is described by (circle): favorable and x: no aptitude.

  The following points were derived from the examples described above. The PET bottle 1 (filled body) according to Example 1 was configured to have light weight and was difficult to be crushed while having sufficient side wall strength. Many monitors supported their ease of holding.

  On the other hand, in Comparative Example 1, although it was reduced in weight and had sufficient side wall strength, it was crushed. In Comparative Example 2, although the resistance to crushing was improved, it was not sufficient, and it did not have light weight. In Comparative Example 3, although the weight was reduced, the side wall strength was insufficient. Therefore, although irreversible bending did not occur, crushing occurred during pouring, and ease of holding was insufficient. And when the weight reduction was a little insufficient like the comparative example 4, side wall strength and crushing difficulty were satisfy | filled.

  From the results of the above examples, in the PET bottle 1 and the filling body according to the present embodiment, even when the weight is reduced, the side wall strength, i.e., the rigidity is sufficient, but the crushing does not easily occur and also has the ease of holding. It was shown that Therefore, in this embodiment, it was shown that the square-shaped PET bottle 1 which is hard to be crushed while having rigidity and excellent in ease of holding while having light weight can be provided.

  The present disclosure can be suitably used for various plastic bottles filled with liquid as contents. However, the present disclosure is not limited to the above-described embodiments and examples. Plastic bottles of the present disclosure include, for example, various non-carbonated beverages such as water, green tea, oolong tea, black tea, coffee, fruit juice, and soft drinks, or seasonings such as soy sauce, sauce, mirin, edible oil, foods including alcoholic beverages, etc. Useful for containing detergents, shampoos, cosmetics, pharmaceuticals, and any other contents. In particular, the plastic bottle of the present disclosure is suitable for use in a large bottle whose weight is increased by a large amount of contents because the container is easy to hold. Furthermore, since the plastic bottle of the present disclosure is excellent in the operability of the container when the contents are poured out, the plastic bottle is also suitable for applications such as transferring from a large bottle to a container for dispensing.

1 PET bottle (plastic bottle)
10 mouth part 20 shoulder part 30 trunk part 31 plane part 31m center part 31p peripheral part 32 corner part 40 bottom part 50 upper side rectangular tube part (square tube part)
51 Circumferential groove (groove)
Dc Corner depth Dm Center depth Dp Perimeter depth Wc Corner width Wm Center width Wp Perimeter width

Claims (8)

A plastic having a mouth portion, a shoulder portion, a trunk portion, and a bottom portion in the axial direction sequentially, and the trunk portion including a plurality of plane portions and a corner portion connecting the plane portions adjacent in the circumferential direction. In the bottle
The rectangular tube portion has a groove that goes around the plastic bottle,
The plastic bottle according to claim 1, wherein the groove has a constant width over the entire circumference, and has a smaller depth at a central portion of the flat portion than at a peripheral portion of the flat portion. The plastic bottle according to claim 1, wherein the groove has a smaller depth in the corner portion than in the central portion. 3. The groove according to claim 1, wherein a value of a ratio of a depth at the central portion to a depth at the peripheral portion is 0.45 or more and 0.95 or less. Plastic bottle as described in. The plastic bottle according to any one of claims 1 to 3, wherein a distance between the adjacent grooves is constant over the entire circumference. 5. The plastic bottle according to claim 1, wherein the groove has a curved shape in a cross section in the axial direction. The plastic bottle according to any one of claims 1 to 5, wherein an inner volume of the plastic bottle is 680 ml or more and 2500 ml or less. The plastic bottle according to any one of claims 1 to 6, wherein a ratio of a mass to a volume of the plastic bottle is 0.0105 g / ml or more and 0.0300 g / ml or less. A plastic bottle according to any one of claims 1 to 7,
A filling body comprising a liquid to be filled.

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