JP2020045153A - Plastic bottle - Google Patents

Abstract

To provide a lightweight square plastic bottle in which a high strength near a lower shoulder part located between a shoulder part and a trunk part is maintained and a shoulder collapse is prevented.SOLUTION: The plastic bottle includes a mouth part, a shoulder part, a trunk part and a bottom part, and has vertical ribs provided on a lower shoulder part located at a boundary between the shoulder part and the trunk part. The vertical rib is a concave rib, and its cross sectional shape is V shape, trapezoid, or U shape. Five to fifteen vertical ribs of a lower shoulder wall part are formed with equal intervals, and one to three vertical ribs of a lower shoulder corner part are formed. Furthermore, the vertical rib projects upward from a boundary line between an upper shoulder part and the lower shoulder part by 0.5 mm or more and 4 mm or less, and in addition, projects downward from the boundary line between the shoulder part and the trunk part by 0.5 mm or more and 4 mm or less.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a plastic bottle, and more particularly, to a structure of a lightweight plastic bottle.

  For example, a plastic bottle is used as a container filled with a beverage. And the production volume of plastic bottles is increasing every year. On the other hand, the weight of plastic bottles is reduced by reducing the use of raw materials from the viewpoint of reducing energy consumption and carbon dioxide emissions by saving resources, reducing garbage, and reducing the environmental burden during transportation. Is being worked on.

  When the weight of the plastic bottle is reduced, the thickness of the container of the plastic bottle becomes thinner, so that the strength of the plastic bottle tends to decrease. The plastic bottles are stored and transported as a single pallet by stacking a plurality of containers packed in a cardboard or the like with a plurality of containers facing upward. At that time, if the plastic bottle does not have enough buckling strength to withstand the load in the vertical direction, buckling deformation may occur and load collapse may occur.

  Further, if the plastic bottle does not have sufficient side wall strength to withstand the horizontal load, the lower plastic bottle is deformed to the side in a vending machine in which the plastic bottle is loaded horizontally. Is likely to occur, and may not be properly discharged from the vending machine. Note that the characteristic of whether or not a plastic bottle is normally discharged from a vending machine is also referred to as vendor suitability.

  By the way, the shapes of the plastic bottles are roughly classified into a round bottle having a circular cross section of the body of the container and a square bottle having a substantially square cross section of the body of the container. In a round bottle, the label attached to the periphery of the container may be difficult to see from directly in front of the container. On the other hand, square bottles are unlikely to cause the above-described problems, and are excellent in loading efficiency and display efficiency, and there is a great demand for square bottles having these advantages.

  However, the strength as described above, especially the buckling strength, is that in the case of a round bottle, the vertical load is effectively distributed to the circular body, whereas the body forms the surface and the corner. In the case of a square bottle composed of a pillar (pillar), a bias load is applied to the pillar portion, so that the bottle becomes weak. Therefore, when the weight of the square bottle is reduced, a measure for strength is particularly required.

JP 2011-73752 A

  According to the synthetic resin blow bottle of Patent Literature 1, since the upper cylindrical portion of the cylindrical blow bottle located between the shoulder and the body is provided with the depressed vertical rib, It is said that crushing buckling deformation from the upper cylindrical portion to the shoulder can be effectively suppressed.

  However, in Patent Literature 1, the formed vertical rib is provided only in the upper cylindrical portion at the boundary between the shoulder and the trunk, and does not extend to the shoulder. No consideration is given to the strength against crushing when an external impact force is applied. Further, the shape of the plastic bottle is a cylindrical shape, and no consideration is given to the body wall portion and the corner portion specific to the square bottle.

  The phenomenon of the collapse near the lower shoulder where the plastic bottle switches from the shoulder to the torso becomes more remarkable as the plastic bottle is lighter. If the plastic bottle is crushed in the vicinity of the lower shoulder where the plastic bottle is switched from the shoulder to the torso, the contents may leak due to an external impact force generated during transportation or the like, and the value of the product may be reduced. Therefore, a lightweight, rectangular plastic bottle needs to maintain strength against the lower shoulder that switches from the shoulder to the trunk.

  Therefore, an object of the present invention is to provide a plastic bottle in which a high-strength portion in the vicinity of a lower shoulder portion that switches from a shoulder portion to a torso portion is maintained and a shoulder collapse is prevented in a lightweight, rectangular plastic bottle. .

  In order to solve the above problem, the plastic bottle of the present invention is a square plastic bottle having a mouth, a shoulder, a trunk, and a bottom, and from a lower shoulder located below the shoulder. It is characterized by having a vertical rib extending in the vertical direction in the vicinity of the joint with the body.

  Further, the mass ratio of the plastic bottle to the volume is 0.020 g / ml or more and 0.044 g / ml or less.

  Furthermore, the lower shoulder portion is composed of a plurality of lower shoulder wall portions and a lower shoulder corner portion connecting the lower shoulder wall portions, and the vertical rib is formed of the lower shoulder wall portion or the lower shoulder corner portion. It is characterized in that at least one is provided along a line extending in the vertical direction at substantially the center in the horizontal direction.

  Further, the vertical rib is a concave rib, and the cross-sectional shape is V-shaped, trapezoidal, or U-shaped.

  Further, 5 to 15 vertical ribs of the lower shoulder wall are formed at equal intervals, and 1 to 3 vertical ribs of the lower shoulder corner are formed. .

  Further, the interval between the vertical ribs is 2 mm or more and 6 mm or less.

  Further, the vertical rib is formed on the lower shoulder in a vertical direction, further projects upward from a boundary line between the upper shoulder and the lower shoulder by 0.5 mm or more and 4 mm or less, and further downward. It protrudes from the boundary line between the shoulder and the body by 0.5 mm or more and 4 mm or less.

  ADVANTAGE OF THE INVENTION According to the plastic bottle of this invention, in the square-shaped plastic bottle which has a mouth part, a shoulder part, a trunk | drum, and a bottom part, the joining part of the torso from the lower shoulder located under a shoulder. , The vertical ribs extending in the vertical direction are provided in the vicinity of the container, so that the buckling strength is increased in the lightweight container, and it becomes possible to avoid crushing deformation when an external impact force is applied.

  Furthermore, according to the plastic bottle of the present invention, the ratio of the mass to the capacity of the plastic bottle is 0.020 g / ml or more and 0.044 g / ml or less. Therefore, it is possible to reduce the burden on the environment and reduce the production cost.

  Further, according to the plastic bottle of the present invention, the lower shoulder portion is composed of a plurality of lower shoulder wall portions and a lower shoulder corner portion connecting the lower shoulder wall portions, and the vertical rib is formed on the lower shoulder wall portion or the lower portion. Since at least one is provided along the line extending in the vertical direction at substantially the center in the horizontal direction of the shoulder corner portion, in a lightweight container, buckling strength is increased, and when an external impact force is added, Collapse deformation can be avoided. By providing it in the center, it is possible to most effectively reinforce the lower shoulder.

  Furthermore, according to the plastic bottle of the present invention, the vertical ribs are concave ribs, and the cross-sectional shape is V-shaped, trapezoidal, or U-shaped. Therefore, when an external impact force is applied, it is possible to avoid crush deformation. In addition, such a simple cross-sectional shape enhances the productivity and reduces the production cost.

  Further, according to the plastic bottle of the present invention, 5 to 15 vertical ribs on the lower shoulder wall are formed at regular intervals, and 1 to 3 vertical ribs on the lower shoulder corner are formed. Therefore, in a lightweight container, the formation of a plurality of vertical ribs further enhances the buckling strength, making it possible to prevent deformation near the lower shoulder when an external impact force is applied Become.

  Furthermore, according to the plastic bottle of the present invention, the interval between the vertical ribs is 2 mm or more and 6 mm or less. Therefore, in a lightweight container, the buckling strength is increased, and when an external impact force is applied. Thus, it is possible to avoid crush deformation.

  Furthermore, according to the plastic bottle of the present invention, the vertical ribs are formed in the lower shoulder in the vertical direction, and further project upward from the boundary between the upper shoulder and the lower shoulder by 0.5 mm or more and 4 mm or less, Furthermore, it is characterized by protruding downward from the boundary between the shoulder and the torso by 0.5 mm or more and 4 mm or less, so that the strength is increased over a wide range near the lower shoulder and an external impact force is added In this case, it is possible to avoid crushing deformation when the sheet is loaded horizontally or in a vending machine.

FIG. 2 is a front view illustrating an example of the plastic bottle according to the embodiment. It is a top view of the plastic bottle of FIG. It is a bottom view of the plastic bottle of FIG. FIG. 3 is a view as viewed in the direction of arrow I in FIG. 2. It is a front enlarged view from the shoulder part of FIG. 1 to a trunk | drum. FIG. 6 is a sectional view taken along line II-II of FIG. 5. FIG. 2 is an exploded view of the pressure absorbing panel of FIG. 1 exploded into a concave panel and a convex panel. FIG. 8 is an enlarged view of a cross section taken along line III-III of the lower diagram of FIG. FIG. 8 is an enlarged view of a cross section taken along line IV-IV in FIG. The direction of the arrow indicates the outside of the plastic bottle. FIG. 2 is an enlarged front view of a circumferential groove in FIG. 1. It is a front view showing another composition of this embodiment. It is a front view showing a comparative example. It is a figure which shows the falling direction at the time of a drop test.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing an example of a plastic bottle 1 according to the present embodiment. FIG. 2 is a plan view of the plastic bottle 1 of FIG. 1, and FIG. 3 is a bottom view of the plastic bottle 1 of FIG. FIG. 4 is a view in the direction of arrow I in FIG. In the following, for convenience of explanation, in the state of FIG. 1 in which the plastic bottle 1 is erected, the mouth portion 10 of the plastic bottle 1 in which the contents are filled in the container is the upper side.

  As shown in FIGS. 1 to 3, the plastic bottle 1 according to the present embodiment has a mouth portion 10, a shoulder portion 20, a trunk portion 30, and a bottom portion 40. Hereinafter, as a preferred embodiment of the plastic bottle 1 according to the present embodiment, a square bottle having a substantially rectangular cross section in a horizontal direction will be exemplified and described in detail.

  The mouth 10 serves as a filling port, a spout, or a drinking spout for the contents, and the plastic bottle 1 is hermetically sealed by attaching a lid (not shown) to the mouth 10.

  As shown in FIG. 1, the shoulder portion 20 and the trunk portion 30 include a plurality of wall portions 51 and a corner portion 52 connecting the wall portions 51 to each other. The wall portion 51 includes the shoulder wall portion 21 and the trunk wall portion. The corner portion 52 is divided into the shoulder corner portion 22 and the torso corner portion 32.

  The shoulder 20 has an upper side connected to the mouth 10, while a lower side connected to the trunk 30. The shoulder portion 20 has a shape of a truncated quadrangular pyramid whose diameter increases from above to below. As shown in FIG. 2, since the plastic bottle 1 is a square bottle, the shoulder portion 20 has four shoulder wall portions 21 having the same shape as each other, and further, the shoulder wall portions 21 are adjacent to each other. A shoulder corner portion 22 is formed therebetween. Further, the shoulder wall portion 21 is divided into an upper shoulder wall portion 21A and a lower shoulder wall portion 21B, and the shoulder corner portion 22 is divided into an upper shoulder corner portion 22A and a lower shoulder corner portion 22B. Further, the upper shoulder wall portion 21A and the upper shoulder corner portion 22A rapidly increase in diameter from the mouth portion 10, and the lower shoulder wall portion 21B and the lower shoulder corner portion 22B gradually increase in diameter. Note that the upper shoulder wall 21A and the upper shoulder corner 22A are collectively referred to as an upper shoulder. Further, the lower shoulder wall 21B and the lower shoulder corner 22B are collectively referred to as a lower shoulder.

  The torso portion 30 is composed of a torso wall portion 31 and a torso corner portion 32. The torso wall portion 31 is divided into an upper torso wall portion 31A and a lower torso wall portion 31B. It is divided into an upper trunk corner 32A and a lower trunk corner 32B.

  Specifically, the shoulder portion 20 is connected to the upper trunk wall portion 31A and the upper trunk corner portion 32A. The upper shoulder wall portion 21A is preferably formed by two panels divided in the vertical direction from the viewpoint of improving the strength of the shoulder portion 20. Note that the vertical division is preferably on a line extending upward from the center of the wall portion 51 from the viewpoint of improving strength. On the other hand, the upper shoulder corner portion 22A may be formed by one panel.

FIG. 5 is an enlarged front view from the shoulder to the trunk. FIG. 6 is a sectional view taken along line II-II of FIG. As shown in FIG. 6, the lower shoulder wall portion 21B and the lower shoulder corner portion 22B are provided with a vertical rib 53 which is a V-shaped concave groove. The vertical rib 53 is formed in a vertical direction, and has a linear shape in a front view. As shown in FIG. 5, the upper end of the vertical rib 53 formed on the lower shoulder wall 21B protrudes upward in the direction of the upper shoulder wall 21A, the lower end protrudes downward in the direction of the upper trunk wall 31A, and the lower shoulder corner is formed. The upper end of the vertical rib 53 formed in the portion 22B protrudes upward in the direction of the upper shoulder corner 22A, and the lower end protrudes downward in the direction of the upper trunk corner 32A.
Therefore, the vertical ribs 53 are formed on the lower shoulder wall portion 21B and the lower shoulder corner portion 22B (lower shoulder portion) which gradually increase in diameter downward, and further project in the vertical direction, so that they are formed diagonally. It is formed to be substantially bent. Due to the shape of the vertical rib 53, the strength is increased and buckling deformation can be prevented.

  Further, as shown in FIG. 6, the vertical rib 53 has a V-shaped cross section as shown in FIG. The groove may have a trapezoidal cross section in which the groove side surfaces rise from both ends in the width direction of the bottom portion, or may have a U-shaped cross section.

  When an external force is applied to the vicinity of the lower shoulder located below the shoulder 20 so that the area near the lower shoulder is pushed into the container and deformed, the area is deformed so that a broken line is generated in the lateral direction. . By providing the vertical ribs 53 perpendicular to the broken line, a restoring force against such a shape change can be exhibited, and permanent deformation of the plastic bottle 1 can be suppressed. That is, it is possible to prevent so-called crushing of the shoulder near the lower shoulder below the shoulder 20 due to an impact from the outside, that is, to crush the shoulder, and to increase the buckling strength in the vertical direction.

  Further, from the viewpoint of buckling strength, it is preferable to have at least one vertical rib 53 on a line extending in the vertical direction substantially at the center of the lower shoulder wall portion 21B or the lower shoulder corner portion 22B in the horizontal direction. By providing the vertical rib 53 at the center of the lower shoulder wall portion 21B or the lower shoulder corner portion 22B, the strength of the plastic bottle 1 can be most effectively maintained. Further, it is preferable that an odd number of the vertical ribs 53 are provided for the lower shoulder wall portion 21B and the lower shoulder corner portion 22B. In particular, it is preferable to form 5 to 15 vertical ribs 53 of the lower shoulder wall portion 21B. Further, it is preferable that one to three vertical ribs 53 are formed on the lower shoulder corner portion 22B. By forming a larger number of vertical ribs, buckling strength is increased, and it is possible to prevent load collapse.

  Further, from the viewpoint of buckling strength, the upper end of the vertical rib 53 formed on the lower shoulder wall portion 21B is provided so as to protrude upward in the direction of the upper shoulder wall portion 21A at a position of 0.5 mm or more and 4 mm or less. Is preferably provided so as to protrude downward at a position of 0.5 mm or more and 4 mm or less in the direction of the upper trunk wall 31A. Further, the upper end of the vertical rib 53 formed on the lower shoulder corner portion 22B is provided so as to protrude upward in the direction of the upper shoulder corner portion 22A at a position of 0.5 mm or more and 4 mm or less, and the lower end is provided on the upper trunk corner portion 32A. It is preferable to be provided so as to protrude downward at a position of 0.5 mm or more and 4 mm or less. Further, the vertical ribs 53 formed on the lower shoulder wall portion 21B or the lower shoulder corner portion 22B and adjacent in the circumferential direction are preferably provided at equal intervals of 2 mm or more and 6 mm or less. By forming the vertical ribs having a structure protruding in the vertical direction in this manner, it is possible to further increase the buckling strength and prevent deformation when an impact is applied.

  Next, details of the body wall 31 of the plastic bottle 1 will be described. The lower diagram of FIG. 7A is an enlarged front view of the upper trunk wall 31A in the plastic bottle of FIG. The upper diagram of FIG. 7A shows a cross-sectional view taken along line IV-IV of the lower diagram of FIG. 7A corresponding to each part of the lower diagram of FIG. 7A. FIGS. 7B and 7C are exploded views in which the pressure absorbing panel 35 of FIG. 7A is disassembled into a concave panel and a convex panel. 7 (b) and the upper diagram of FIG. 7 (c) are cross-sectional views taken along the line IV-IV of the lower diagram of FIG. 7 (a) corresponding to each part of each exploded view. The left view of FIG. 8 is an enlarged view of a cross section taken along line III-III of FIG. The left diagram in FIG. 8 is shown corresponding to each part of the pressure absorbing panel 35 in the right diagram. In the left view of FIG. 8, the direction of the arrow indicates the outside of the plastic bottle 1. FIG. 9 is a partially enlarged view of a cross section taken along line IV-IV of FIG. The direction of the arrow indicates the outside of the plastic bottle 1.

  As shown in FIG. 1, the trunk wall 31 is divided into an upper trunk wall 31 </ b> A and a lower trunk wall 31 </ b> B at a substantially middle part in the vertical direction, and includes a pressure absorbing panel 35. The pressure absorbing panel 35 absorbs a change in pressure inside the plastic bottle 1, particularly, a change in reduced pressure, and maintains the strength of the plastic bottle 1, particularly, the strength of the side wall. The pressure absorbing panel 35 is preferably in a substantially rectangular shape in which each corner is rounded off from the viewpoint of preventing pressure from dispersing and preventing body swelling.

  Hereinafter, the pressure absorbing panel 35 will be described. However, since the upper body wall 31A and the lower body wall 31B have the same configuration, only the upper body wall 31A will be described and the structure of the lower body wall 31B will be described. Is omitted.

  As shown in FIGS. 7, 8 and 9, the pressure absorbing panel 35 is provided in a vertical window shape on the upper trunk wall 31 </ b> A, and the concave panel 34 is formed so as to surround the convex panel 33. The convex panel 33 and the concave panel 34 have a substantially rectangular shape, and the surface 33 a of the convex panel 33 is formed so as to be located more inward than the outermost surface 31 a of the trunk wall portion 31.

  The depth d1 of the convex panel 33 is 0.5 to 5 mm, preferably 1 to 3 mm, and the depth d2 of the concave panel 34 is 1 to 7 mm, preferably 1.5 to 4 mm. d1 and d2 have a relationship of d1 <d2. If the depths d1 and d2 are too small, it becomes difficult to absorb the load due to the change in the internal pressure of the plastic bottle 1, while if the depths d1 and d2 are too large. At the time of molding the plastic bottle 1, poor shaping and whitening due to overstretching are likely to occur.

  The ratio d1 / d2 of the depth d1 of the convex panel to the depth d2 of the concave panel is 0.5 or more and 0.9 or less. Preferred from a viewpoint.

  The inclination angle θ1 on the side surface 33b of the convex panel 33 is preferably 5 degrees ≦ θ1 ≦ 80 degrees, and the inclination angle θ2 on the side surface 34b of the concave panel 34 is preferably 5 degrees ≦ θ1 ≦ 80 degrees. Is preferred. In consideration of blow moldability and mold release properties after molding, it is more preferable that 30 degrees ≦ θ1 ≦ 60 degrees and 30 degrees ≦ θ2 ≦ 60 degrees. Note that θ1 and θ2 may all be the same value or different values.

  Here, if the surface 33a of the convex panel 33 is a flat surface, the deformation when the container is held becomes remarkable. Therefore, it is preferable that a plurality of concave ribs 36 are formed on the surface 33a of the convex panel 33 so as to be recessed inward from the surface 33a of the convex panel 33 and extend linearly in the horizontal direction. According to this configuration, the flat portion on the panel surface is eliminated, and the pressure is dispersed at the concave ribs, thereby further preventing the body from bulging.

  However, if the number of the concave ribs 36 is too large, the pressure absorbing panel 35 is less likely to be deformed inward of the plastic bottle 1, and the function of absorbing pressure is lost. Therefore, it is preferable that 4 to 12 concave ribs 36 are arranged on the surface 33 a of the convex panel 33. By setting the number of the concave ribs 36 to four or more, a high pressure reduction properness is exhibited, the rigidity of the upper body wall portion 31A is increased, the pressure applied to the plastic bottle 1 is dispersed, and the effect of preventing body swelling is sufficiently achieved. can get. In the example of FIGS. 7 and 8, seven concave ribs 36 are arranged.

  Each concave rib 36 extends continuously from the left end to the right end on the surface 33 a of the convex panel 33. The concave rib 36 is formed over the entire area in the vertical direction from the upper end to the lower end of the surface 33 a of the convex panel 33. The concave ribs 36 are not limited to being formed over the entire area in the vertical direction of the surface 33a of the convex panel 33 of each pressure absorbing panel 35, but may be a part of each pressure absorbing panel 35, for example, each pressure absorbing panel 35. May be formed only in the upper half, the lower half, or the center in the vertical direction.

  As shown in FIG. 8, the surface 33a of the substantially flat convex panel 33 is connected to the substantially flat rib bottom surface 36a of the concave rib 36 via a rib side surface 36b.

  Here, assuming that the thickness at the surface 33a of the convex panel 33 is t, the depth d3 of the concave rib 36 has a relationship of 1.5t ≦ d3 ≦ 10t, more preferably 2t ≦ d3 ≦ 5t. When d3 <1.5t, the surface 33a of the convex panel 33 and the concave rib 36 are hardly formed as shapes. On the other hand, when d3> 10t, the shapeability tends to deteriorate.

  It is preferable that the width w2 of the surface 33a of the convex panel 33 be 2d3 ≦ w2 ≦ 20d3 with respect to the depth d3 of the concave rib 36. Since the surface 33a of the convex panel 33 has a concave shape in a blow molding die, by setting 2d3 ≦ w2, the surface 33a of the convex panel 33 can be easily shaped during blow molding. Note that, as a rule of thumb, the width is preferably at least twice the depth (2d3 ≦ w2) to facilitate shaping during blow molding. On the other hand, by setting the width w2 of the surface 33a of the convex panel 33 to 20d3 or less (w2 ≦ 20d3), the reduced pressure absorbing function and the reinforcing function can be sufficiently exhibited. The surfaces 33a of the plurality of convex panels 33 of each pressure absorbing panel 35 may all have the same width w2.

  The width w1 of the concave rib 36 is preferably d3 ≦ w1 ≦ 20d3 with respect to the depth d3 of the concave rib 36, and more preferably 2d3 ≦ w1 ≦ 20d3. Since the concave rib 36 becomes a protrusion having a height d3 in the blow molding die, the protrusion of the blow molding die does not become too large if d3 is not too large relative to the width w1. Therefore, the strength of the portion corresponding to the protrusion of the blow molding die is prevented from being weakened. Therefore, at least the width w1 is preferably at least d3, more preferably at least twice d3. On the other hand, by setting the width w1 of the concave rib 36 to 20d3 or less (w1 ≦ 20d3), the reduced pressure absorbing function and the reinforcing function can be sufficiently exhibited. The plurality of concave ribs 36 of each pressure absorbing panel 35 may have the same width w1.

  It is preferable that the inclination angles θ3 and θ4 of the rib side surface 36b satisfy 5 degrees ≦ θ3 ≦ 80 degrees and 5 degrees ≦ θ4 ≦ 80 degrees. In consideration of blow moldability and mold release properties after molding, it is more preferable that 15 degrees ≦ θ3 ≦ 45 degrees and 15 degrees ≦ θ4 ≦ 45 degrees. Note that θ3 and θ4 may be the same value or different values.

  In addition, in one plastic bottle 1 or one pressure absorption panel 35, each of the dimensions d3, w1, w2, etc. does not need to be all the same value, and should be appropriately designed with different values satisfying the above-described relationship. Can be. Further, the configuration of the pressure absorbing panel 35 and the concave rib 36 of the upper trunk wall portion 31A can be arbitrarily combined with the configuration of the pressure absorbing panel 35 and the concave rib 36 of the lower trunk wall portion 31B within a range not inconsistent. It is.

The plastic bottle 1 has a slight oxygen permeability. When the storage in the plastic bottle 1 is performed for a long period of time, oxidation occurs depending on the contents, and the pressure in the plastic bottle 1 is reduced. In addition, the pressure inside the plastic bottle 1 changes depending on the temperature difference between the time of filling the contents and the time of storage. The plastic bottle 1 in which the pressure is reduced is pulled inward and deformed.
At this time, in the pressure absorbing panel 35, the uneven surface of the surface 33a of the convex panel 33, the side surface 33b of the convex panel 33, the bottom surface 34a of the concave panel 34, the side surface 34b of the concave panel 34, and the concave rib 36 is extended. This easily deforms inward. The pressure absorbing panel 35 serves to prevent deformation of the entire plastic bottle 1 by depressing inward of the plastic bottle 1 when the inside of the plastic bottle 1 is depressurized. That is, even if a water head pressure is applied to the plastic bottle 1, the rigidity of the uneven surface of the pressure absorbing panel 35 is increased, and the pressure is dispersed, so that blistering can be prevented.

  The pressure absorbing panel 35 plays a role in preventing the entire plastic bottle 1 from being deformed even when the pressure inside the plastic bottle 1 is increased. With the pressure absorbing panel 35 having such a configuration, when the plastic bottle 1 is opened, it is possible to prevent the wall of the plastic bottle 1 from being pressed inward and the contents from being pushed out of the mouth 10 and spilling. . And the pressure absorption panel 35 can increase the rigidity of the trunk | drum 30.

  The upper body wall 31A of the plastic bottle 1 is a portion to which a label is attached. The label is attached by, for example, a shrink label that shrinks a heat-shrinkable film such as a polystyrene (PS: PolyStyrene) or a polyethylene terephthalate (PET: PolyEthylene Terephthalate) covered with a plastic bottle 1 with hot air. You. Since the size of the tubular heat-shrinkable film is determined to a predetermined value, if the upper trunk wall 31A is swollen, the heat-shrinkable film may be clogged or may not enter.

  Therefore, it is preferable that the pressure absorbing panel 35 is configured so as not to protrude outside the upper trunk wall 31A of the plastic bottle 1. That is, it is preferable that the surface 33 a of the convex panel 33 be located more inward than the outermost surface 31 a of the body wall portion 31, and the surface 33 a of the convex panel 33 be provided with the concave rib 36. As a result, the label can be smoothly mounted on the upper trunk wall 31A, the packing efficiency of the box packing on cardboard or the like is excellent, and the productivity can be improved. Further, by providing the pressure absorbing panel 35, it is possible to maintain a good appearance of the product in which the contents are filled in the plastic bottle 1 and prevent the product value from decreasing.

  As described above, the surface 33a of the convex panel 33 of the pressure absorbing panel 35 preferably includes a plurality of concave ribs 36 extending in the horizontal direction, but the surface 33a of the convex panel 33 may be in any direction. It may have a concave or convex rib (not shown) extending. When a plurality of ribs extending in an arbitrary direction are provided on the surface 33a of the convex panel 33, it is preferable that the ribs are formed so as to intersect with each other from the viewpoint of the strength of the upper trunk wall portion 31A. Further, it is preferable that at least one of the intersections of the ribs is located on a line extending in the vertical direction substantially at the center in the left-right direction of the upper trunk wall portion 31A, and is located near the center of the upper trunk wall portion 31A. It is more preferable from the viewpoint of preventing dimensional change due to the above. Therefore, the ribs are preferably formed in an X shape, a cross shape, or the like. Plastic bottles 1 having these shapes are more excellent in design.

  Further, in the case of a convex rib, it is preferable that the surface of the convex portion of the rib is located inside the outermost surface 31 a of the body wall portion 31. That is, the rib protruding further outward from the surface 33a of the convex panel 33, which protrudes outward by one step from the bottom surface 34a of the concave panel 34 which indents one step inward from the surface of the upper trunk wall portion 31A, The protruding height is equal to or less than the outermost surface 31a of the body wall portion 31. Therefore, when the plastic bottle 1 is viewed from just beside the projecting direction of the convex rib, the convex rib is not visible. The ribs configured in this way do not affect the dimensions of the facing surface of the plastic bottle 1. Therefore, the plastic bottle 1 according to the present embodiment is excellent in the loading efficiency of packing in a cardboard or the like. Further, the plastic bottle 1 according to the present embodiment has an effect of not affecting the attachment of the shrink label.

  It is preferable that an annular peripheral groove 38 crossing the body wall 31 and the body corner 32 is provided between the upper body wall 31A and the lower body wall 31B. The circumferential groove 38 improves the strength of the side wall, which is the strength withstanding the horizontal load of the body 30. The ratio H2 / H1 of the height H2 from the ground surface of the bottom portion 40 to the circumferential groove 38 and the total height H1 of the plastic bottle 1 is not less than 0.3 and not more than 0.8. It is preferable from the viewpoint of appropriately exhibiting the effect of the present embodiment, which prevents more. When the ratio H2 / H1 is less than 0.3, the resin does not easily reach the bottom portion 40 during the molding of the plastic bottle 1, so that shaping defects such as whitening are likely to occur. On the other hand, when the ratio H2 / H1 is larger than 0.8, the side wall strength decreases.

  The upper torso wall portion 31A and the upper torso corner portion 32A are formed in a tapered shape so as to decrease in diameter from above and to be connected to the circumferential groove 38, and the lower torso wall portion 31B and the lower torso corner portion 32B It is formed in a tapered shape so as to decrease in diameter from below and upward so as to be continuous with the peripheral groove 38, and that the peripheral groove 38 is constricted so as to have a minimum diameter of the body portion 30, so that it is easy to carry, easy to drink, It is preferable from the viewpoint of appropriately exhibiting the effect of further preventing the body swelling.

  Here, the configuration of the peripheral groove 38 will be described in detail. FIG. 10 is an enlarged view of a front portion of the circumferential groove 38. The circumferential groove 38 is formed so as to be wider from both ends of the trunk corner portion 32 toward the center. That is, the width c2 of the peripheral groove 38 at the center of the trunk corner 32 is larger than the width c1 of the peripheral groove 38 at both ends of the trunk corner 32. With this configuration, the rigidity of the body 30 can be increased.

  The ratio of c2 / c1 is preferably from 1.1 to 3.0 from the viewpoint of buckling strength and shapeability. When the ratio of c2 / c1 is smaller than 1.1, the effect of preventing stress concentration is hardly exhibited. On the other hand, if the ratio of c2 / c1 is larger than 3.0, it becomes a bending point at the time of vertical load.

  Next, details of the bottom portion 40 of the plastic bottle 1 will be described. The bottom part 40 has a ground part 41, a side part 42 connected to the trunk 30 from the outer peripheral edge of the ground part 41, and an inner part 43 located inside the ground part 41. Further, a rib 44 extending toward the center is formed on the inner portion 43. Therefore, for example, it is possible to prevent the bottom portion 40 from being deformed such as being inverted by an internal pressure generated by an impact such as a drop.

  The shape of the grounding portion 41 may be a polygonal shape such as a hexagon or a circular shape, or a shape in which a part of the outer circumference of a circle is a straight line.

  The plastic bottle 1 according to the present embodiment is not limited by size, and can be applied to various sizes. For example, the volume of the plastic bottle 1 may be 200 ml to 2000 ml, and is particularly suitable for the plastic bottle 1 having a volume of 500 ml to 1000 ml. In particular, the overall height H1 of the plastic bottle 1 is preferably 120 mm to 260 mm, and the diameter of the body 30 is preferably 40 mm to 70 mm, so that the effects of the plastic bottle 1 according to the present embodiment can be suitably obtained.

  Furthermore, the plastic bottle 1 according to the present embodiment can be suitably used for a lightweight bottle. The mass of the plastic bottle 1 may be, for example, 12 g or more and less than 18 g for 600 ml, 22 g or more and less than 32 g for 720 ml, and 23 g or more and less than 37 g for 930 ml. In particular, from the viewpoint of maintaining the strength of the plastic bottle 1 while having a light weight and increasing the absorption amount of the change in the internal pressure, the value of the mass ratio to the volume of the plastic bottle 1 is 0.020 g / ml or more. It is preferably at most 044 g / ml. Such a lightweight plastic bottle saves resources, reduces waste, reduces environmental load, and reduces production costs.

  As the thermoplastic resin constituting the plastic bottle 1, for example, a thermoplastic polyester such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, or a copolymer thereof, these resins, or other resins Is particularly preferable, and particularly, ethylene terephthalate-based thermoplastic polyester such as polyethylene terephthalate can be suitably used. Further, acrylonitrile resin, polyethylene, polypropylene, propylene-ethylene copolymer and the like can also be used. Further, a biomass-based plastic derived from a plant, for example, polylactic acid (PLA) can be used. The above-mentioned resin is blended with various additives such as a colorant, an ultraviolet absorber, a release agent, a lubricant, a nucleating agent, an antioxidant, an antistatic agent and the like, as long as the quality of the molded article is not impaired. can do. Preferably, the plastic bottle 1 is sterilized by adding hydrogen peroxide and peracetic acid.

  As the ethylene terephthalate-based thermoplastic resin constituting the plastic bottle 1, most of the ester repeating portion, generally 70 mol% or more, is occupied by ethylene terephthalate units, and has a glass transition point (Tg) of 50 to 90 ° C; Those having a melting point (Tm) in the range of 200 to 275 ° C are suitable. As ethylene terephthalate-based thermoplastic polyester, polyethylene terephthalate is particularly excellent in terms of pressure resistance and the like, but in addition to ethylene terephthalate units, diphthalic acids such as isophthalic acid and naphthalenedicarboxylic acid and diols such as propylene glycol. A copolyester containing a small amount of an ester unit consisting of

  Further, the plastic bottle 1 may be composed of two or more thermoplastic polyester layers. Further, when the plastic bottle 1 is composed of two or more thermoplastic polyester layers, a barrier layer or an intermediate layer such as an oxygen absorbing layer can be provided between the layers. As the oxygen absorbing layer, a layer containing a combination of an oxidizable organic component and a transition metal catalyst, or a gas barrier resin that does not substantially oxidize can be used.

  The plastic bottle 1 can be manufactured by molding a preform manufactured by injection molding of the above-described material by blow molding.

  As described above, the plastic bottle 1 according to the present embodiment has the mouth 10, the shoulder 20, the trunk 30, and the bottom 40. A vertical rib 53 is formed on the lower shoulder wall 21B and the lower shoulder corner 22B (lower shoulder) located at the boundary between the shoulder 20 and the body 30. According to the configuration according to the present embodiment, in the square plastic bottle 1 that is reduced in weight, the rigidity in the vicinity of the lower shoulder from the shoulder 20 on which the vertical rib 53 is formed to the trunk 30 is increased, and the seat is increased. Flexural deformation can be suppressed. It is possible to prevent dents caused by dropping during transportation.

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

<Material>
[Example 1]
The plastic bottle 1 according to the present embodiment shown in FIG. 1 was used. That is, in the plastic bottle 1, the vertical rib 53 is formed on the lower shoulder below the shoulder 20. The number of the vertical ribs 53 formed on the lower shoulder wall portion 21B is seven. One vertical rib 53 is provided on the lower shoulder corner portion 22B. The plastic bottle 1 was made of polyethylene terephthalate, weighed 25 g, and had a capacity of 900 ml. The plastic bottle 1 was produced by blow molding a preform.

[Example 2]
FIG. 11 shows a second embodiment. The plastic bottle 100 has a vertical rib 153 formed on a lower shoulder located below the shoulder. Here, the number of the vertical ribs 153 of the lower shoulder wall portion 121B is one. Except for the number of the vertical ribs, the configuration is the same as that of the first embodiment.

[Comparative Example 1]
Comparative Example 1 shown in FIG. 12 has a configuration including a mouth 210, a shoulder 220, a trunk 230, and a bottom 240, and is a 900 ml plastic bottle 200. This plastic bottle is a square bottle. Also, unlike the embodiment, no vertical rib is formed on the lower shoulder. The plastic bottle 200 having this configuration was manufactured by blow molding a 25 g preform.

<Method>
(Drop test)
Drop tests were performed to examine the strength of Examples 1 and 2 and Comparative Example 1. The plastic bottle was filled with green tea so that the head space was 20 ml, and the mouth was sealed with a cap. 15 plastic bottles were put in one box. The bottles were dropped in the direction shown in FIG.

(Comprehensive evaluation)
The plastic bottles of Examples 1, 2 and Comparative Example 1 were comprehensively evaluated. Fifteen pieces were put in one box, and the number of dents in the lower shoulder portion when the pieces fell down was examined. Table 1 shows the results of the comprehensive evaluation. ◎: excellent, ：: good, Δ: suitable but not good, ×: not suitable.

  A comprehensive evaluation was made on the above-mentioned drop test, and the following points were derived. As shown in Table 1, in Example 1, the weight was reduced, the number of dents was 0 in the drop test, and the buckling strength was sufficient. In Example 2, the number of dents in the drop test is two, which is acceptable. From this, it is considered that the small number of vertical ribs is the cause of the dent. In Comparative Example 1, the number of dents in the drop test was 7, the vertical buckling strength was weak, and the sample was not suitable.

  From Example 1 described above, the plastic bottle 1 according to the present embodiment has good suitability in a drop test due to the plurality of vertical ribs 53 formed on the lower shoulder located at the boundary between the shoulder and the trunk. As a result, it was shown that high buckling strength was maintained in a lightweight, rectangular plastic bottle.

  The present disclosure can be suitably used for various plastic bottles for aseptic filling, heat resistance, and the like. However, the present disclosure is not limited to the above-described embodiments and examples. The plastic bottle of the present disclosure includes, in its contents, for example, green tea, oolong tea, black tea, coffee, fruit juice, various non-carbonated beverages such as soft drinks, or seasonings such as soy sauce, sauce, mirin, edible oil, foods containing alcoholic beverages It is useful for all containers containing detergents, shampoos, cosmetics, pharmaceuticals, etc., and is suitable for sales by vending machines and the like because containers can be loaded sideways.

DESCRIPTION OF SYMBOLS 1 Plastic bottle 10 Mouth 20 Shoulder 21 Shoulder wall 21A Upper shoulder wall 21B Lower shoulder wall 22 Shoulder corner 22A Upper shoulder corner 22B Lower shoulder corner 30 Body 31 Body wall 31A Upper body wall 31B Lower trunk wall part 31a Outermost surface of trunk wall part 32 Trunk corner part 32A Upper trunk corner part 32B Lower trunk corner part 33 Convex panel 33a Surface of convex panel 33b Side of convex panel 34 Concave panel 34a Bottom of concave panel 34b Side surface of concave panel 35 Pressure absorbing panel 36 Concave rib 36a Rib bottom surface 36b Rib side surface 38 Peripheral groove 40 Bottom 41 Grounding part 42 Side part 43 Inner part 44 Rib 51 Wall part 52 Corner part 53 Vertical rib H1 Overall height of plastic bottle H2 Bottom part From the ground contact surface to the circumferential groove

Claims (7)

Mouth and
Shoulders,
A torso,
The bottom,
In a rectangular plastic bottle having
It has a vertical rib extending vertically from the lower shoulder located below the shoulder to the vicinity of the joint with the trunk.
Plastic bottle. The mass ratio of the plastic bottle to the volume is 0.020 g / ml or more and 0.044 g / ml or less,
The plastic bottle according to claim 1. The lower shoulder portion includes a plurality of lower shoulder wall portions and a lower shoulder corner portion connecting the lower shoulder wall portions,
The vertical rib is characterized in that at least one of the lower shoulder wall portion or the lower shoulder corner portion is provided along a line extending in a vertical direction substantially in the center in the horizontal direction,
The plastic bottle according to claim 1. The vertical rib is a concave rib,
The cross-sectional shape is V-shaped, trapezoidal, or U-shaped,
The plastic bottle according to claim 1. The vertical ribs of the lower shoulder wall portion are formed at regular intervals of 5 to 15 ribs,
The vertical rib of the lower shoulder corner portion is characterized in that one to three ribs are formed,
The plastic bottle according to claim 1. The interval between the vertical ribs is 2 mm or more and 6 mm or less,
The plastic bottle according to claim 5. The vertical rib is formed on the lower shoulder in a vertical direction, further projects upward from a boundary line between the upper shoulder and the lower shoulder by 0.5 mm or more and 4 mm or less, and furthermore, the shoulder extends downward. Characterized in that it protrudes from 0.5 mm to 4 mm from the boundary between the part and the trunk.
The plastic bottle according to claim 1.

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