JP6421581B2 - Plastic bottle - Google Patents

Description

  The present invention relates to a plastic bottle, and more particularly, to a structure of a plastic bottle that is reduced in weight.

  For example, a plastic bottle is used as a container filled with a beverage. And the production volume of plastic bottles is increasing year by year. On the other hand, the plastic bottles are lightened by reducing the amount of raw materials used from the viewpoint of reducing energy consumption and carbon dioxide emissions by saving resources, reducing waste, and reducing the environmental impact during transportation. Is addressed.

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

  Furthermore, if the plastic bottle does not have sufficient side wall strength to withstand the horizontal load, the plastic bottle at the lower level in the vending machine where the plastic bottle is loaded sideways is deformed to the side. May occur and may not be properly discharged from the vending machine. The characteristic of whether or not the plastic bottle is normally discharged from the vending machine is also referred to as vendor aptitude.

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

  However, in the case of a round bottle, the above-mentioned strength, particularly the buckling strength, effectively distributes the load in the vertical direction to the circular barrel, whereas the barrel forms a surface and a corner. In a square bottle composed of pillars (pillars), the load on the pillars is unbalanced and weakens. Therefore, when the square bottle is reduced in weight, a countermeasure for strength is particularly necessary.

  In the blow molded bottle having a substantially square cross section of the shoulder portion and the trunk portion disclosed in Patent Document 1, the wall thickness of the bottle wall is made as thin as possible in order to reduce the amount of raw material resin used. In addition, the body part is composed of an upper body part, a lower body part, and a laterally concave rib provided between the upper body part and the lower body part, and each of the upper body part and the lower body part. Is composed of four side walls and four corner walls each disposed between the side walls, and the corner walls are formed with recesses extending in the axial direction, which are tapered walls.

International Publication No. 2002/087978

  According to the blow-molded bottle of Patent Document 1, since the concave portion extending in the axial direction is provided in the corner wall of the trunk portion, it is possible to manufacture a thin-walled bottle in which the rigidity of the corner wall is enhanced and the corner wall is reinforced. Thus, it is said that the amount of resin used can be reduced. However, in Patent Document 1, although the rigidity (strength) of the corner wall is considered, no consideration is given to the strength of the side wall.

  On the other hand, when the contents are filled in the plastic bottle, the plastic bottle is pushed outward by the water head pressure. In the case of a round bottle, the pressure is dispersed in the entire circumferential direction of the body part, so that the body part hardly bulges. On the other hand, since there is a straight portion in the circumferential direction in the body portion of the square bottle, a phenomenon called a so-called body bulge that protrudes outward tends to occur, and the phenomenon becomes so light that the plastic bottle is lighter Becomes prominent. In addition, swelling of the trunk tends to occur on the side wall at the lower part of the trunk that is easily subjected to water head pressure by the contents.

  If a plastic bottle bulges and protrudes from a predetermined design dimension, it will be clogged in the production line or in a vending machine, packed in cardboard, or displayed on a product shelf. You may not be able to enter the market, or the value of the product may decline. Therefore, the weight-reduced rectangular plastic bottle is required to maintain strength and prevent dimensional change.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic bottle capable of preventing dimensional change due to swelling of a body portion while maintaining high strength, particularly buckling strength, in a lightweight square plastic bottle.

In order to solve the above problems, a plastic bottle of the present invention has a mouth, a shoulder, a trunk, and a bottom, and the trunk includes a plurality of wall sections and a corner connecting the wall sections. A plastic bottle in which the wall portion is divided into an upper wall portion and a lower wall portion, the wall portion has a rib extending in an arbitrary direction, and the upper wall portion is 1 A pressure absorbing panel recessed inwardly of the step, wherein a plurality of the ribs of the upper wall portion extend in a horizontal direction of the pressure absorbing panel, and the lower wall portion is centered from both ends of the wall portion in the horizontal direction. The plastic bottle is curved inward, and is curved inward in the vertical direction from the upper and lower ends of the lower wall portion toward the middle point .

  Furthermore, it has an intersection where the plurality of ribs intersect with each other, and the intersection is located on a line extending in the vertical direction about the horizontal center of the wall portion.

Furthermore, it has an intersection where the plurality of ribs intersect, and the intersection is located in the vicinity of the center of at least one surface of the upper wall portion and the lower wall portion.

  Furthermore, the ribs of the upper wall part and / or the lower wall part are convex, and the convex ribs do not protrude outward of the plastic bottle from the surface connecting the both ends. It is characterized by that.

Furthermore, the ribs of the upper wall portion is characterized by a concave-shaped rib.

Furthermore, the rib of the lower wall section, characterized in that between the ends of the lower wall portion is a plurality of grooves extending in the horizontal direction.

  Furthermore, an annular circumferential groove that crosses the wall portion and the corner portion is provided between the upper wall portion and the lower wall portion.

  Furthermore, the corner portion has a vertical groove extending in the vertical direction.

Furthermore, the depth of the longitudinal groove is greater than the depth of the annular circumferential groove that is provided between the upper wall portion and the lower wall portion and crosses the wall portion and the corner portion. Features.

  Furthermore, a first chamfered portion that is chamfered is provided between the corner portion of the body portion and the shoulder portion.

  Furthermore, a second chamfered portion that is chamfered is provided between the corner portion of the body portion and the bottom portion.

Further, the longitudinal groove extending in the vertical direction of the corner portion extends below the both ends of the groove at the lowermost end of the plurality of grooves extending in the horizontal direction between the both ends. And

  Furthermore, the groove part positioned on the lower side of the plurality of groove parts is characterized by an arc shape curved downward from the both end parts of the wall part toward the center.

Furthermore, below the groove portion at the lowermost end, there is another groove portion located below the longitudinal groove extending in the vertical direction of the corner portion, and both ends of the another groove portion are formed on the wall portion. It does not extend to the both ends.

  Further, the groove portion has a maximum depth at the center.

Furthermore, the depth of the longitudinal groove extending in the longitudinal direction of the corner portion is larger than the depth at the center of the groove portion.

Further, an annular circumferential groove that is provided between the upper wall portion and the lower wall portion and crosses the wall portion and the corner portion is widened from the both end portions of the wall portion toward the center. It is formed so that it may become.

  Further, the shoulder portion is connected to the wall portion and the corner portion, and the shoulder portion connected to the wall portion is formed by four panels divided in a horizontal direction and a vertical direction. And

Furthermore, the ratio of the bending amount at the center of the wall portion to the width between the both end portions of the wall portion is 0.01 or more and 0.2 or less.

Furthermore, the height from the ground contact surface of the bottom portion to the annular circumferential groove across the wall portion and the corner portion, provided between the upper wall portion and the lower wall portion, and the total height of the plastic bottle, The ratio is from 0.3 to 0.8.

According to the plastic bottle of the present invention, it has a mouth portion, a shoulder portion, a trunk portion, and a bottom portion, and the trunk portion includes a plurality of wall portions and a corner portion connecting the wall portions, and the wall portion. However, in the plastic bottle divided into the upper wall portion and the lower wall portion, the wall portion has a rib extending in an arbitrary direction, and the upper wall portion has a pressure absorbing panel recessed inwardly by one step. A plurality of ribs on the upper wall portion extending in the horizontal direction of the pressure absorbing panel, and the lower wall portion being curved inward of the plastic bottle in the horizontal direction from both ends of the wall portion to the center, and in the vertical direction. The lower wall portion is curved inward from the upper and lower end portions of the plastic bottle toward the middle point, so that in a lighter container, it is possible to prevent swelling of the body while maintaining strength. In addition, the label can be smoothly attached to the upper wall portion, and productivity can be improved.

  Further, according to the plastic bottle of the present invention, the plurality of ribs have intersections, and the intersections are located on a line extending in the vertical direction from the substantially horizontal center of the wall portion. In addition, swelling of the body can be prevented while maintaining strength.

Furthermore, according to the plastic bottle of the present invention, there is an intersection where a plurality of ribs intersect, and the intersection is located in the vicinity of the center of at least one surface of the upper wall portion and the lower wall portion, thus reducing the weight. In the container, swelling of the body can be prevented while maintaining strength.

  Further, the ribs on the upper wall part and / or the lower wall part are convex, and the convex rib does not protrude outward from the plastic bottle from the surface connecting the both ends. In addition, while maintaining strength, it is possible to prevent swelling of the body, and it does not affect the dimensions of the plastic bottle facing each other. Therefore, it is possible to make the loading efficiency of boxing on cardboard or the like excellent.

Further, according to a plastic bottle of the present invention, the ribs of the upper wall, because it is concave-shaped rib, in containers lightweight, can be further prevented blistering cylinder while maintaining the strength.

Furthermore, according to the plastic bottle of the present invention, the rib of the lower wall portion is a plurality of grooves extending horizontally between both ends of the lower wall portion, so that the strength is increased while absorbing the pressure fluctuation in the container. Can be held.

  Furthermore, according to the plastic bottle of the present invention, since the annular peripheral groove that crosses the wall portion and the corner portion is provided between the upper wall portion and the lower wall portion, the side wall strength can be improved.

  Furthermore, according to the plastic bottle of the present invention, the corner portion has a longitudinal groove extending in the longitudinal direction, so that the buckling strength can be improved.

Further, according to the plastic bottle of the present invention, the depth of the longitudinal groove is larger than the depth of the annular circumferential groove that is provided between the upper wall portion and the lower wall portion and crosses the wall portion and the corner portion. Thus, the buckling strength can be further improved.

  Furthermore, according to the plastic bottle of the present invention, since the chamfered first chamfered portion is provided between the corner portion of the trunk portion and the shoulder portion, the buckling strength can be further improved.

  Furthermore, according to the plastic bottle of the present invention, since the second chamfered portion is chamfered between the corner portion and the bottom portion of the trunk portion, the buckling strength can be further improved.

Furthermore, according to the plastic bottle of the present invention , the longitudinal groove extending in the vertical direction of the corner portion projects below both ends of the lowermost groove portion among the plurality of groove portions extending in the horizontal direction between the both end portions. Therefore, it is possible to prevent the swelling of the trunk at the corner of the trunk close to the bottom.

  Furthermore, according to the plastic bottle of the present invention, the groove portion located on the lower side of the plurality of groove portions has an arc shape curved downward from both ends of the wall portion toward the center, so that the body portion close to the bottom portion It is possible to prevent swelling of the body at the wall portion.

Furthermore, according to the plastic bottle of the present invention, the lower corner of the groove has another groove located below the longitudinal groove extending in the longitudinal direction, and both ends of the other groove are Since it does not extend to both ends of the wall portion, it is possible to prevent the swelling of the body portion closer to the bottom portion.

  Furthermore, according to the plastic bottle of the present invention, since the groove portion has the largest depth at the center, it is possible to further prevent the swelling of the trunk.

Furthermore, according to the plastic bottle of the present invention, the depth of the longitudinal groove extending in the longitudinal direction of the corner portion is larger than the depth at the center of the groove portion , so that the buckling strength can be further improved. .

Furthermore, according to the plastic bottle of the present invention, the annular circumferential groove that crosses the wall portion and the corner portion provided between the upper wall portion and the lower wall portion is directed from the both end portions of the wall portion toward the center, Since it forms so that it may become wide, the intensity | strength of a wall part, especially buckling intensity | strength can be improved more.

  Furthermore, according to the plastic bottle of the present invention, the shoulder portion is connected to the wall portion and the corner portion, and the shoulder portion connected to the wall portion is formed by four panels divided in the horizontal direction and the vertical direction. Therefore, the strength of the shoulder can be improved.

Furthermore, according to the plastic bottle of the present invention, the ratio of the amount of curvature at the center of the wall portion to the width between both end portions of the wall portion is 0.01 or more and 0.2 or less. Swelling can be further prevented.

Furthermore, according to the plastic bottle of the present invention, the height from the ground contact surface at the bottom to the annular circumferential groove that crosses the wall and the corner, provided between the upper wall and the lower wall, and the plastic bottle Since the ratio to the total height is 0.3 or more and 0.8 or less, it is possible to further prevent the swelling of the trunk while maintaining the strength.

It is the front view by which an example of the plastic bottle which concerns on this embodiment was shown. It is a top view of the plastic bottle of FIG. It is a bottom view of the plastic bottle of FIG. FIG. 4 is a view in the direction of arrows IV in FIG. 2. It is an enlarged view of the front part of an upper wall part. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. It is an enlarged view of the front part of a circumferential groove. It is an enlarged view of the front part of a lower wall part. It is the IX-IX sectional view taken on the line of FIG. It is the XX sectional view taken on the line of FIG. It is a front view of the modification of a lower wall part. It is the XII-XII sectional view taken on the line of FIG. It is the XIII-XIII sectional view taken on the line of FIG. It is a front view of the plastic bottle of a comparative example. It is a top view of the plastic bottle of FIG. It is a bottom view of the plastic bottle of FIG. It is a front view of the plastic bottle of another comparative example. It is a top view of the plastic bottle of FIG. It is a bottom view of the plastic bottle of FIG.

  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. 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. 4 is a front view of the plastic bottle 1 as viewed from the direction of the arrow IV in FIG. 2, that is, as viewed from the direction in which the plastic bottle 1 of FIG. 1 is rotated 45 degrees in the circumferential direction in plan view. 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 referred to as the upper side.

  As shown in FIGS. 1 to 3, the plastic bottle 1 according to this embodiment includes a mouth portion 10, a shoulder portion 20, a trunk portion 30, and a bottom portion 40. The body portion 30 includes a plurality of wall portions 31 and a corner portion 32 that connects the wall portions 31, and the wall portion 31 is divided into an upper wall portion 33 and a lower wall portion 34. 1, at least the lower wall portion 34 is characterized in that it is curved inward of the plastic bottle 1 from the both end portions 36, 36 of the wall portion 31 toward the center in the horizontal direction.

  Further, the upper wall portion 33 and the lower wall portion 34 may have concave or convex ribs extending in an arbitrary direction. In particular, the lower wall portion 34 is horizontally between both end portions 36 and 36. It is preferable to have groove portions 37 as a plurality of ribs extending in the direction. Further, in the case where a plurality of ribs extending in an arbitrary direction are provided, it is preferable that intersecting intersections are formed, and these intersections are arranged near the centers of the upper wall portion 33 and the lower wall portion 34. More preferably. Furthermore, it is preferable that the convex rib does not protrude outward from both end portions 36, 36. Below, as a suitable aspect of the plastic bottle 1 which concerns on this embodiment, the square bottle whose cross-sectional view of a horizontal direction is substantially square is illustrated and demonstrated in detail.

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

  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 portion 20 has a substantially quadrangular pyramid shape that expands from the upper side to the lower side. As shown in FIG. 2, since the plastic bottle 1 is a square bottle, the shoulder portion 20 is configured by four surfaces of a shoulder portion 20A, a shoulder portion 20B, a shoulder portion 20C, and a shoulder portion 20D in a clockwise direction. . More specifically, the shoulder portion 20 has four wall portions having the same shape, and a corner portion is formed between adjacent wall portions. Although it is preferable that the shoulder portion 20 has an outwardly curved shape from the viewpoints of strength and formability that indicates followability to the designed shape, the shoulder portion 20 may have an inwardly curved shape. The shape is not particularly limited. In the following description, explanation will be made by taking up one surface including the shoulder portion 20A, and as appropriate, reference numerals A to D are given to the respective portions of the four surfaces in the circumferential direction as described above.

  Specifically, the shoulder portion 20 is connected to the wall portion 31 and the corner portion 32. From the viewpoint of improving the strength of the shoulder, the wall portion of the shoulder portion 20 connected to the wall portion 31 is formed by the four panels 21, 22, 23, and 24 divided in the horizontal direction and the vertical direction. preferable. The vertical division is preferably on a line extending upward from the center of the wall portion 31 from the viewpoint of improving the strength. On the other hand, the corner portion of the shoulder portion 20 connected to the corner portion 32 may be formed by one panel 25.

  The trunk portion 30 has four wall portions 31 (31A, 31B, 31C, and 31D) having the same shape as each other, and has a substantially square tube shape as a whole (see FIG. 2). . Further, corner portions 32 (32A, 32B, 32C, and 32D) that are curved outward are formed between adjacent wall portions 31 (see FIG. 2). The corner portion 32 may be flat without being curved outward. However, from the viewpoint of the buckling strength in the vertical direction, it is preferable that the corner portion 32 is curved outward and has a shape close to a cylinder. Furthermore, the trunk portion 30 is not limited to a regular rectangular tube shape, and may be a multi-sided cylindrical shape, and particularly if it is an even-numbered multi-sided cylindrical shape, it can be suitably used for a vending machine. preferable. Furthermore, the trunk portion 30 may have a long rectangular tube shape.

  The wall portion 31 is divided into an upper wall portion 33 and a lower wall portion 34 at a substantially intermediate portion in the vertical direction. The upper wall portion 33 includes a pressure absorption panel 35. On the other hand, the lower wall portion 34 has a plurality of groove portions 37. Details of these will be described later.

  Between the upper wall portion 33 and the lower wall portion 34, it is preferable to have an annular circumferential groove 38 that crosses the wall portion 31 and the corner portion 32. The circumferential groove 38 improves the side wall strength, which is the strength withstanding the load in the horizontal direction of the body portion 30. The ratio H2 / H1 between the height H2 from the ground contact surface of the bottom portion 40 to the circumferential groove 38 and the total height H1 of the plastic bottle 1 is 0.3 or more and 0.8 or less, so that the body swells while maintaining the strength. This is preferable from the viewpoint of appropriately exhibiting the effect of the present embodiment to be further prevented. If the ratio H2 / H1 is less than 0.3, the resin is difficult to reach the bottom 40 side when the plastic bottle 1 is molded, so that shaping defects such as whitening tend to occur. On the other hand, if the ratio H2 / H1 is larger than 0.8, the side wall strength is lowered.

  On the other hand, if there is even one horizontal reinforcing rib such as the circumferential groove 38, it becomes a cushion, and the displacement increases although it does not buckle with respect to the load in the vertical direction. And the buckling strength in the range where a displacement is small falls. Therefore, when the circumferential groove 38 is formed, the corner portion 32 preferably has a vertical groove 39 extending in the vertical direction (see FIGS. 1 and 4). The longitudinal groove 39 improves the buckling strength of the trunk portion 30. At least one vertical groove 39 is formed. Depending on circumstances, the number of longitudinal grooves 39 may be two to three. When the number of the longitudinal grooves 39 is too large, the unevenness increases and the formability deteriorates.

  The corrugated cardboard in which the plastic bottle 1 is boxed sinks due to the load from above, and the sinking cost is determined. Therefore, it is important to enhance the load resistance against the displacement of the plastic bottle 1 within the range of the sinking allowance. Therefore, the plastic bottle 1 according to the present embodiment is configured so that the cushion is intentionally eliminated and the load resistance in the vertical direction is increased.

  It is preferable to have a chamfered portion 50 that is chamfered between the corner portion 32 of the trunk portion 30 and the panel 25 of the shoulder portion 20. The chamfered portion 50 is located immediately above the vertical groove 39. In the region between the body portion 30 and the shoulder portion 20, particularly between the corner portion 32 and the panel 25, an uneven load is easily applied to the load in the vertical direction. And in the shape of the plastic bottle 1 which concerns on this embodiment, since a spring is hard to be effective with respect to the load of an up-down direction, this area | region tends to become a buckling generation location. Therefore, when the chamfered portion 50 is formed in this region, the load is prevented from being concentrated, and the buckling strength of the plastic bottle 1 is further increased. The chamfered slope is more preferably an angle that is a half of the angle formed by the reference line and the panel 25 with a line extending upward from the corner portion 32 as a reference line.

  Next, the detail of the upper wall part 33 of the plastic bottle 1 is demonstrated. FIG. 5 is an enlarged view of a front portion of the upper wall portion 33, and FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. In FIG. 6, the right side shows the inside of the plastic bottle 1. The upper wall portion 33 includes a pressure absorbing panel 35 that is recessed inward by one step, and the pressure absorbing panel 35 preferably includes a plurality of concave ribs 60 that extend in the horizontal direction. The pressure absorbing panel 35 absorbs the pressure change inside the plastic bottle 1, particularly the reduced pressure change, and maintains the strength of the plastic bottle 1, particularly the side wall strength.

  The pressure absorbing panel 35 includes a stepped wall surface 61 that is recessed inward by one step from the surface of the surrounding upper wall portion 33, and a plurality of recessed ribs 60 that are further recessed inward from the stepped wall surface 61 and extend linearly in the horizontal direction. Have Furthermore, a connection surface 62 is formed so as to surround the periphery of the step wall surface 61. The connection surface 62 is inclined with respect to the step wall surface 61.

  When the surface of the upper wall portion 33 has a flat configuration, the deformation when the container is held becomes significant. Therefore, the rigidity of the upper wall portion 33 is increased by adopting the configuration having the concave rib 60. However, if there are too many concave ribs 60, the pressure absorption panel 35 cannot be deformed inward of the plastic bottle 1, and the pressure absorption function is lost. Accordingly, the number and size of the concave ribs 60 are designed to be appropriate. In the illustration of FIG. 5 and FIG. 6, ten concave ribs 60 are arranged.

  The depth s of the step wall surface 61 that is recessed inward by one step from the surface of the upper wall portion 33 is 0.5 to 2 mm, preferably 1 mm, from the surface of the surrounding upper wall portion 33. When the depth s is small, it is difficult to absorb the load due to the change in the internal pressure of the plastic bottle 1, while when the depth s is large, the plastic bottle 1 is molded due to poor shaping or overstretching. Whitening is likely to occur.

  Each concave rib 60 extends continuously from the left end to the right end of the connection surface 62. The concave rib 60 is formed over the entire area in the vertical direction from the upper end to the lower end excluding the connection surface 62 of the pressure absorbing panel 35. The concave rib 60 is not limited to being formed over the entire vertical direction of each pressure absorbing panel 35, but a part of each pressure absorbing panel 35, for example, the upper half, the lower half of each pressure absorbing panel 35, You may form only in the center part of an up-down direction.

  It is preferable that at least 4 or more and 12 or less concave ribs 60 are arranged in the pressure absorbing panel 35. When the number of the concave ribs 60 is four or more, the reduced-pressure absorption function can be sufficiently exerted, and further, the effect of reinforcing the plastic bottle 1 by sufficiently dispersing the stress applied to the plastic bottle 1 can be obtained. .

  As shown in FIG. 6, the surface of the stepped wall surface 61 is a substantially flat flat surface 61a. A substantially flat flat surface 60 a is formed at the bottom of the concave rib 60. Further, an inclined surface 63 is formed between the step wall surface 61 and the concave rib 60.

  Here, when the thickness of the stepped wall surface 61 is t, the depth d1 of the concave rib 60, that is, the distance d1 between the flat surface 61a and the flat surface 60a is t ≦ d1 ≦ 10t, more preferably t ≦ d1. ≦ 5t. When d1 ≦ t, the step wall surface 61 and the concave rib 60 are difficult to form as shapes. On the other hand, if d1 is large, the formability tends to deteriorate.

  The width a of the stepped wall surface 61 is preferably 2d1 ≦ a ≦ 20d1. Since the stepped wall surface 61 has a concave shape in the blow molding die, by setting 2d1 ≦ a, it becomes easier to shape the stepped wall surface 61 during blow molding. As a rule of thumb, in order to facilitate shaping during blow molding, the width is preferably at least twice the depth (2d1 ≦ a). On the other hand, by setting the width a of the stepped wall surface 61 to 20 d1 or less (a ≦ 20 d1), the reduced pressure absorption function and the reinforcing function can be sufficiently exhibited. The plurality of step wall surfaces 61 of each pressure absorbing panel 35 may all have the same width a.

  The width b of the concave rib 60 is preferably d1 ≦ b ≦ 20d1, and more preferably 2d1 ≦ b ≦ 20d1. Since the concave rib 60 is a protrusion having a height d1 in the blow mold, the protrusion of the blow mold does not become too large because d1 is not too large with respect to the width b. For this reason, it is prevented that the intensity | strength of the part corresponded to the projection part of a blow molding metal mold | die becomes weak. Accordingly, at least the width b is preferably not less than d1, and more preferably not less than twice d1. On the other hand, by setting the width b of the concave rib 60 to 20 d1 or less (b ≦ 20 d1), the reduced pressure absorption function and the reinforcing function can be sufficiently exhibited. The plurality of concave ribs 60 of each pressure absorbing panel 35 may all have the same width b.

  The angles θ1 and θ2 of the inclined surface 44 are preferably 0 degrees ≦ θ1 and θ2 ≦ 80 degrees. In consideration of blow moldability and mold release after molding, it is more preferable that 5 ° ≦ θ1 and θ2 ≦ 80 °. Note that θ1 and θ2 may be the same value or different values.

  Note that, in one plastic bottle 1 or one pressure absorption panel 35, the dimensions a, b, d1, etc. do not have to all be the same value, and may be different values satisfying the above-described relationship. .

  The plastic bottle 1 has a slight oxygen permeability. And when the preservation | save in the plastic bottle 1 is extended over a long period, depending on the content, oxidation will occur and the inside of the plastic bottle 1 will be decompressed by this. In addition, the pressure inside the plastic bottle 1 also changes depending on the temperature difference between the filling of the contents and the storage. The plastic bottle 1 in which decompression has occurred is pulled inward to cause deformation. At this time, the pressure absorbing panel 35 is easily deformed inward by extending the uneven surfaces of the stepped wall surface 61 and the concave rib 60. The pressure absorption panel 35 plays a role of preventing deformation of the entire plastic bottle 1 by being recessed inward of the plastic bottle 1 when the inside of the plastic bottle 1 is depressurized. That is, the pressure absorbing panel 35 is configured not to protrude outward from the upper wall portion 33 of the plastic bottle 1 but to be recessed to some extent inward.

  The pressure absorbing panel 35 plays a role of preventing deformation of the entire plastic bottle 1 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 and spilled out from the mouth portion 10. . And the pressure absorption panel 35 can improve the rigidity of the trunk | drum 30. FIG.

  The upper wall 33 of the plastic bottle 1 is a part where a label is attached. For example, the label is attached by a shrink label that is shrunk by applying hot air to a heat-shrinkable film such as cylindrical polystyrene (PS: PolyStyrene) or polyethylene terephthalate (PET) that is placed on the plastic bottle 1. The And since the dimension of a cylindrical heat-shrinkable film is decided to the predetermined value, when the upper wall part 33 is swollen, the malfunction that a heat-shrinkable film is blocked | filled or does not enter arises.

  However, by providing the pressure absorbing panel 35, the outward protrusion of the upper wall portion 33 is prevented, the label is smoothly attached, and the productivity can be improved. Furthermore, by providing the pressure absorbing panel 35, it is possible to maintain a good appearance of the product in which the plastic bottle 1 is filled with the contents, and to prevent a reduction in the product value.

  As described above, the pressure absorption panel 35 preferably includes a plurality of concave ribs 60 extending in the horizontal direction, but the upper wall portion 33 includes concave or convex ribs (not shown) extending in an arbitrary direction. You may have. In the case where a plurality of ribs extending in an arbitrary direction are provided on the upper wall portion 33, it is preferable from the viewpoint of the strength of the upper wall portion 33 that the ribs are formed to intersect each other. Further, it is preferable that at least one of the intersecting points of the ribs is located on a line extending in the vertical direction from the substantially center in the left-right direction of the upper wall portion 33, and being located in the vicinity of the center of the upper wall portion 33 due to body bulging It is more preferable from the viewpoint of preventing dimensional change. Therefore, the rib is preferably formed in an X shape, a cross shape, or the like. The plastic bottle 1 having these shapes is superior in design.

  Furthermore, in the case of a convex rib, it is preferable that the convex portion of the rib does not protrude outward from the surface of the upper wall portion 33. That is, the protruding height of the rib protruding outward from the step wall surface 61 that is recessed inward by one step from the surface of the upper wall portion 33 is the same as or less than the surface of the upper wall portion 33. Accordingly, when the plastic bottle 1 is viewed from the side of the protruding direction of the convex rib, the convex rib cannot be seen. The rib configured in this way does not affect the size 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 boxing on cardboard or the like. Furthermore, the plastic bottle 1 according to the present embodiment also has an effect that does not affect the mounting of the shrink label.

  Next, the configuration of the circumferential groove 38 will be described in detail. FIG. 7 is an enlarged view of the front portion of the circumferential groove 38. The circumferential groove 38 is formed so as to become wider from both end portions of the wall portion 31 toward the center. That is, the width c2 of the circumferential groove 38 at the center of the wall portion 31 is larger than the width c1 of the circumferential groove 38 at both ends of the wall portion 31. With this configuration, the rigidity of the trunk portion 30 can be increased.

  The ratio of c2 / c1 is preferably 1.1 to 3.0 from the viewpoints of buckling strength and formability. 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 during vertical load.

  Next, the configuration of the lower wall portion 34 will be described in detail. 8 is an enlarged view of the front portion of the lower wall portion, FIG. 9 is a sectional view taken along line IX-IX in FIG. 8, and FIG. 10 is a sectional view taken along line XX in FIG. Note that the right side in FIG. 9 and the upper side in FIG. 10 indicate the inside of the plastic bottle 1.

  The lower wall portion 34 is curved inward of the plastic bottle 1 toward the center from both end portions 36 and 36 of the wall portion 31 in the horizontal direction. With the configuration having the lower wall portion 34 that curves inward, the strength of the plastic bottle 1 is maintained, and the swelling of the contents filled in the plastic bottle 1 due to the water head pressure is prevented. Further, preferably, the lower wall portion 34 includes a plurality of groove portions 37 extending between the both end portions 36 and 36 in the horizontal direction. The structure having the groove portion 37 in the inwardly curved lower wall portion 34 maintains the strength of the plastic bottle 1 and prevents the contents filled in the plastic bottle 1 from being swollen due to the head pressure of the contents. Increase in capacity and dimensional change of the plastic bottle 1 are prevented.

  Unlike the upper wall portion 33, the lower wall portion 34 does not include a pressure absorbing panel. When a bottle having a pressure absorbing panel on the lower side falls, the panel tends to pop out due to an impact. And the panel which has jumped out does not return and becomes a poor appearance, and the commercial value is lowered. For this reason, in the present embodiment, the lower wall portion 34 is configured not to include a panel for pressure absorption in order to prevent such a problem and to prevent the swelling of the trunk.

  The lower wall portion 34 is curved inward of the plastic bottle 1 from the both end portions 36, 36 of the wall portion 31 toward the center in the horizontal direction (see FIG. 10). On the other hand, even in the vertical direction, the plastic bottle 1 is curved inward from the upper and lower ends of the lower wall portion 34 toward the center (near the space between the groove portions 37d and 37e in FIG. 9) (see FIG. 9). .

  The bending amount d2 at the center of the wall portion 31 from the line connecting the both end portions 36, 36 of the wall portion 31 is preferably 1 mm or more and 6 mm or less from the viewpoint of further preventing the swelling of the body while maintaining the strength. If the amount of bending d2 is less than 1 mm, the effect of preventing the swelling of the body is hardly exhibited. On the other hand, if the bending amount d2 is larger than 6 mm, it becomes a bending point during vertical load. And it is preferable that ratio d2 / w1 of the curvature amount d2 in the center of the wall part 31 with respect to the width w1 of the both ends 36 and 36 of the wall part 31 is 0.01 or more and 0.2 or less. When the ratio d2 / w1 between the width w1 and the bending amount d2 is smaller than 0.01, the effect of preventing the swelling of the body is hardly exhibited. On the other hand, if the ratio d2 / w1 between the width w1 and the bending amount d2 is larger than 0.2, it becomes a bending point during vertical load.

  The inwardly curved lower wall portion 34 includes a plurality of groove portions 37a to 37g extending in the horizontal direction between both end portions 36, 36. In the illustration of FIG. 8, seven groove portions 37a to 37g are formed. The structure of these groove portions 37 increases the rigidity and prevents the swelling of the trunk. It is preferable that at least four groove portions 37 are arranged. When the number of the groove portions 37 is four or more, the function of preventing the swelling of the body can be sufficiently exhibited, and further, the effect of reinforcing the plastic bottle 1 by dispersing the stress applied to the plastic bottle 1 can be sufficiently obtained. .

  The groove portion 37 is not formed in the corner portion 32 and is not continuous in the circumferential direction of the plastic bottle 1. The configuration of the non-continuous groove 37 in the circumferential direction prevents the plastic bottle 1 from being easily buckled.

  The groove portion 37 is further recessed inward from the lower wall portion 34 that curves inward (see FIG. 10). The cross-sectional shape of the groove part 37 may be linear as well as curved as shown in FIG. Although it is preferable that the depth d3 of each groove portion 37 is uniform with respect to the surface of the curved lower wall portion 34, as shown in FIG. 10, it is more preferable that the depth d3 is the largest in the vicinity of the center in the horizontal direction. . Since the body bulge is likely to occur at the center of the lower wall portion 34, if the depth d3 of the groove portion 37 is large in the vicinity of the center in the horizontal direction, the center of the lower wall portion 34 does not protrude outward.

  However, if the depth d3 is large, it has an effect of preventing the swelling of the body, but it becomes a shape with severe irregularities, making it difficult to form. Moreover, the plastic bottle 1 that has been reduced in weight is still difficult to be shaped. Therefore, it is preferable that the depth d3 of the groove part 37 near the center in the horizontal direction is 3 mm or more and 10 mm or less.

  Of the plurality of grooves 37, at least the grooves 37 e to 37 g positioned on the lower side may be arcuately curved downward from both ends 36 of the wall 31 toward the center. The lower wall portion 34 of the plastic bottle 1 becomes thinner as it approaches the bottom portion 40, and the water head pressure increases. Therefore, the portion closer to the bottom 40 is more likely to swell. Therefore, the groove portions 37e to 37g are curved downward so that the groove portion 37 covers a portion of the lower wall portion 34 close to the bottom portion 40. Due to the configuration of the arc-shaped groove portions 37e to 37g that are curved downward, the rigidity of the portion close to the bottom portion 40 is increased and the swelling of the body is prevented. In addition, not only the groove part 37e-groove part 37g located in the lower side but the groove part 37a-groove part 37d located in an upper side may be circular arc shape curved downward.

  However, when the end portion 37E of the groove portion 37g is positioned below the lower end 39E of the vertical groove 39, the end portion 37E is likely to be swollen. Therefore, as shown in FIG. 8, the vertical groove 39 protrudes from the both end portions 36, 36 to the lower end 39 E below the both ends 37 E of the bottom end groove portion 37 g among the plurality of groove portions 37 extending in the horizontal direction. Configured to extend. That is, the starting point of the groove portion 37g at the lower end is located above the lower end 39E of the vertical groove 39. With this configuration, the body bulge at the corner portion 32 of the body portion 30 close to the bottom portion 40 is prevented.

  Below the lowermost groove portion 37g, there is another groove portion 37h positioned below the vertical groove 39, and both ends of the other groove portion 37h do not extend to both end portions 36 of the wall portion 31. Accordingly, the groove portion 37 covers a portion of the lower wall portion 34 that is closer to the bottom portion 40. However, if the groove portion 37 in this region is provided so as to extend to the position of the vertical groove 39, the groove portion 37 is easily buckled, so that the groove portion 37 is provided in the middle of the lower wall portion 34 that does not reach the corner portion 32. . Such another configuration of the groove portion 37 h prevents buckling at the trunk portion 30 close to the bottom portion 40. It is preferable that such another groove portion 37h and the above-described groove portions 37a to 37g are configured to cover the entire area in the vertical direction from the upper end to the lower end of the lower wall portion 34. In addition, the shape, such as the width | variety and depth of another groove part 37h, the distance with the adjacent groove part 37, etc. may be the same as that of the groove part 37 mentioned above.

  In addition, the shape of the groove part 37 may be changed depending on the mass of the preform from which the plastic bottle 1 is based. That is, since the thickness of the plastic bottle 1 becomes thinner as the weight of the preform becomes lighter, it is preferable that the arc-shaped groove portions 37e to 37g described above are provided. For example, it is preferable that the groove portion 37 has an arc shape in the case of 20.5 g to 30 g for a 1000 mL container and 12 g to 15 g for a 500 mL container.

  On the other hand, for example, in the case of a 1000 mL container, in the case of 30 g or more and 35 g or less, all the groove portions 37 can be straight. In the case of the mass of the preform in this range, sufficient strength is ensured, so that the groove portion 37 can be omitted. Further, for example, in the case of a 500 mL container, in the case of 15 g or more and 20 g or less, all the groove portions 37 can be made straight, and the groove portions 37 can be omitted. FIG. 11 is a front view of a modified example of the lower wall portion 34. Instead of the groove part 37e to the groove part 37h illustrated in FIG. 8, the modification has a groove part 37i to a groove part 37l. In the case of the mass of the preform in this range, the plastic bottle 1 has a wall thickness that enables the strength of the plastic bottle 1 to be maintained and the swelling of the body to be prevented even if the grooves 37 are all straight. Note that the modified example is similar to the positional relationship of each part described above, and has the same effect.

  As described above, the lower wall portion 34 preferably includes a plurality of groove portions 37a to 37g extending in the horizontal direction between both end portions 36 and 36, but the lower wall portion 34 extends in an arbitrary direction. It may have a concave or convex rib (not shown). In the case where a plurality of ribs extending in an arbitrary direction are provided on the lower wall portion 34, it is preferable from the viewpoint of the strength of the lower wall portion 34 that the ribs are formed to intersect each other. Furthermore, it is preferable that at least one of the intersecting points of the ribs is located on a line extending substantially in the vertical direction between the both end portions 36 and 36, and that it is located in the vicinity of the center of the lower wall portion 34 due to body swelling or the like. It is more preferable from the viewpoint of preventing dimensional change. Therefore, the rib is preferably formed in an X shape, a cross shape, or the like. The plastic bottle 1 having these shapes is superior in design.

  Furthermore, it is preferable that the convex rib does not protrude outward from the surface connecting the both end portions 36 and 36 of the lower wall portion 34. That is, the convex rib protruding outward from the inwardly curved lower wall portion 34 has the same height as the surface connecting the both end portions 36, 36 of the lower wall portion 34, or It is as follows. Therefore, when the plastic bottle 1 is viewed from the side of the protruding direction of the convex rib, the convex rib cannot be seen. The convex ribs configured as described above and the above-described concave ribs do not affect the facing size of the plastic bottle 1. Therefore, the plastic bottle 1 according to the present embodiment is excellent in the loading efficiency of boxing on cardboard or the like. Furthermore, the plastic bottle 1 according to the present embodiment also has an effect that does not affect the mounting of the shrink label.

  The concave and convex ribs of the lower wall portion 34 and the concave and convex ribs of the upper wall portion 33 described above can be arbitrarily combined within a consistent range.

  Next, the dimensions and the like of each groove will be described in detail. 12 is a cross-sectional view taken along line XII-XII in FIG. 4, and FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. In both cases, a horizontal cut surface of the plastic bottle 1 is shown. Therefore, the longitudinal groove 39 indicates the width direction, and the circumferential groove 38 indicates the extending (circulating) direction.

  The vertical groove 39 has a width w2 and a depth d4. In addition, the width w2 and the depth d4 are based on a portion of the corner portion 32 that protrudes to the outermost side of the plastic bottle 1. And it extends in the vertical direction of the plastic bottle 1 with the uniform depth d4 except for the inclined part at the upper end and the lower end of the vertical groove 39.

  The width w2 of the vertical groove 39 is preferably 1 mm or more and 5 mm or less. When the width w2 of the vertical groove 39 is smaller than 1 mm, the effect is lost and the formability is deteriorated. On the other hand, if the width w2 of the vertical groove 39 is larger than 5 mm, it is necessary to widen the corner portion 32, which is not desirable.

  It is preferable that the depth d4 of the vertical groove 39 is 0.5 mm or more and 3 mm or less. If the depth d4 of the vertical groove 39 is smaller than 0.5 mm, the effect is lost. On the other hand, when the depth d4 of the vertical groove 39 is larger than 3 mm, the formability tends to be deteriorated.

  As shown in FIG. 13, the circumferential groove 38 has a depth d5. The depth d4 of the longitudinal groove 39 is larger than the depth d5 of the circumferential groove 38, and the ratio of d4 / d5 is 1.1 to 1.5 from the viewpoint of buckling strength and shaping properties. preferable. If the ratio d4 / d5 is smaller than 1.1, the plastic bottle 1 is likely to be deformed when subjected to a load in the vertical direction. On the other hand, if the ratio of d4 / d5 is larger than 1.5, the formability tends to be deteriorated.

  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 portion 30 is preferably 40 mm to 70 mm, and the effects exhibited by the plastic bottle 1 according to the present embodiment can be suitably obtained.

  As a 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 In particular, an ethylene terephthalate thermoplastic polyester such as polyethylene terephthalate can be preferably used. Furthermore, acrylonitrile resin, polyethylene, polypropylene, propylene-ethylene copolymer and the like can also be used. Furthermore, it is also possible to use plant-derived biomass plastics such as polylactic acid (PLA). Various additives such as colorants, UV absorbers, mold release agents, lubricants, nucleating agents, antioxidants, antistatic agents, etc. are blended with the above-mentioned resins within a range that does not impair the quality of the molded product. can do. The plastic bottle 1 is preferably sterilized by adding hydrogen peroxide and peracetic acid.

  As the ethylene terephthalate-based thermoplastic resin constituting the plastic bottle 1, the ethylene terephthalate unit occupies most of the ester repeating portion, generally 70 mol% or more, 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 preferred. In addition, as an ethylene terephthalate thermoplastic polyester, polyethylene terephthalate is particularly excellent in terms of pressure resistance, but in addition to ethylene terephthalate units, dibasic acids such as isophthalic acid and naphthalenedicarboxylic acid, and diols such as propylene glycol Copolyesters containing a small amount of ester units consisting of can also be used.

  Furthermore, the plastic bottle 1 can be composed of two or more thermoplastic polyester layers. Furthermore, when the plastic bottle 1 is constituted by two or more thermoplastic polyester layers, an intermediate layer such as a barrier layer or 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 produced by molding a preform produced by injection molding of the above-described material by blow molding.

  As described above, in the plastic bottle 1 according to the present embodiment, the trunk portion 30 includes a plurality of wall portions 31 and a corner portion 32 that connects the wall portions 31, and the wall portion 31 is an upper portion. In the plastic bottle 1 divided into the wall portion 33 and the lower wall portion 34, at least the lower wall portion 34 is horizontally oriented from both ends 36 and 36 of the wall portion 31 toward the center, and A plurality of groove portions 37 that are curved inward and extend in the horizontal direction between both end portions 36 and 36 are provided. And according to the structure which concerns on this embodiment, in the square plastic bottle 1 reduced in weight, the dimensional change by the swelling of a trunk | drum etc. is prevented, maintaining high intensity | strength, especially buckling strength.

  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]
A plastic bottle 1 according to this embodiment shown in FIG. 1 was used. In other words, the plastic bottle 1 has a lower wall portion 34 curved inward of the plastic bottle 1, and has a plurality of groove portions 37 extending horizontally between both end portions 36, 36, and the upper wall portion 33 has a pressure The absorption panel 35 is provided, the depth of the vertical groove 39 is deeper than that of the groove portion 37 and the circumferential groove 38, and a chamfered portion 50 is included. The plastic bottle 1 was made of polyethylene terephthalate and had a weight of 25 g and a capacity of 900 ml. The plastic bottle 1 was produced by blow molding a preform.

[Comparative Example 1]
As shown in FIGS. 14 to 16, a 900 ml plastic bottle 300 was tested as a comparative example 1 with a mouth portion 310, a shoulder portion 320, a trunk portion 330, and a bottom portion 340. .

  14 is a front view of the plastic bottle 300, FIG. 15 is a plan view of the plastic bottle 300 of FIG. 14, and FIG. 16 is a bottom view of the plastic bottle 300 of FIG. The shoulder 320 has four side surfaces 321 and is formed in a substantially quadrangular pyramid shape that expands downward. A chamfer 322 is provided at a joint between adjacent side surfaces 321 of the shoulder 320. The side surface 321 includes a plurality of recessed portions 323 whose horizontal cross section is recessed inward in a substantially V shape. The trunk portion 330 has a substantially rectangular tube shape having four side surfaces 331. A chamfer 332 is provided at a joint between adjacent side surfaces 331 of the body portion 330. The body portion 330 includes an annular circumferential groove 380 in the vicinity of the center in the vertical direction. The plastic bottle 300 having such a configuration was produced by blow-molding a 35 g preform.

[Comparative Example 2]
A 900 ml plastic bottle having the same configuration as that of Comparative Example 1 was used as Comparative Example 2. The plastic bottle 300 was produced by blow molding a 25 g preform.

[Comparative Example 3]
A plastic bottle 400 for 900 ml was tested as Comparative Example 3 and provided with a mouth portion 410, a shoulder portion 420, a body portion 430, and a bottom portion 440 shown in FIGS.

  17 is a front view of the plastic bottle 400, FIG. 18 is a plan view of the plastic bottle 400 of FIG. 17, and FIG. 19 is a bottom view of the plastic bottle 400 of FIG. The shoulder 420 is formed in a substantially truncated cone shape that expands downward. The trunk portion 430 is cylindrical and has the same diameter in the vertical direction. The body portion 430 includes a plurality of reinforcing grooves 480 formed of an annular circumferential groove recessed inward. The plastic bottle 400 having such a configuration was manufactured by blow-molding a 25 g preform.

<Method>
(Vertical buckling strength test)
The plastic bottles of Example 1 and Comparative Examples 1, 2, and 3 were filled with green tea so that the head space was 20 ml, and the mouth was sealed with a cap. The vertical buckling strength was measured for each up to 5 mm displacement of the plastic bottle filled with the contents in an upright state. For the measurement of the vertical buckling strength, a tester manufactured by AGR, TOP LOAD, was used. Table 1 shows the results of the test.

(Loading efficiency)
The number of plastic bottles loaded on one pallet in the plastic bottles of Example 1 and Comparative Examples 1, 2, and 3 was compared. The loading efficiency is described as follows: ◯: the number of 400 pallets loaded is 400, and x: the number of pallets loaded is less than 400.

(Assembly test)
The plastic bottles of Example 1 and Comparative Examples 1, 2, and 3 were filled with green tea so that the head space was 20 ml, and the mouth was sealed with a cap. The plastic bottles filled with the contents were arranged in three vertically and four horizontally and packed in cardboard. The corrugated cardboard filled with the plastic bottles was stacked, and an assembly test was conducted to determine whether or not three-layer assembly was possible. Table 1 shows the results of the test. The assembly possibility is indicated by ○: no load collapse, x: load collapse occurred.

(Comprehensive evaluation)
Based on the vertical buckling strength test, the number of pallets, and the assembly test, the plastic bottles of Example 1 and Comparative Examples 1, 2, and 3 were comprehensively evaluated. Table 1 shows the results of comprehensive evaluation. ○: Good, Δ: Appropriate but not good, ×: Not appropriate.

  The following points were derived from the examples described above. As shown in Table 1, Example 1 was able to reduce the weight, and had a function of preventing body swell as well as a buckling strength sufficient for assembling and a proper pressure reduction. In Comparative Example 1, the preform is 35 g, and weight reduction cannot be achieved. In Comparative Example 2, the vertical buckling strength was weak and the body was swollen, so that the loading efficiency was lowered and the assembly was not possible. Since the comparative example 3 was not provided with the pressure absorption part, it did not have pressure reduction aptitude and the loading efficiency was also low.

  From the above-described examples, the plastic bottle 1 according to the present embodiment has a size due to the bulging of the trunk while maintaining high strength, particularly buckling strength, in the light-weight square plastic bottle due to its configuration. It has been shown that changes prevent.

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

DESCRIPTION OF SYMBOLS 1 Plastic bottle 10 Mouth part 20 Shoulder part 21, 22, 23, 24 Panel 30 Trunk part 31 Wall part 32 Corner part 33 Upper wall part 34 Lower wall part 35 Pressure absorption panel 36 Both ends of a wall part 37 Groove part (rib)
37E End portions of the groove portion 37e, 37f, 37g Arc-shaped groove portion 37h Another groove portion 38 Circumferential groove 39 Vertical groove 39E Lower end of the vertical groove 40 Bottom portion 50 Chamfered portion (first chamfered portion)
51 Chamfer (second chamfer)
60 Concave rib c1 Width of circumferential groove at both ends c2 Width at the center of circumferential groove d2 Amount of curvature of lower wall d4 Depth of vertical groove d5 Depth of circumferential groove H1 Total height of plastic bottle H2 Circumference from bottom contact surface Height to groove w2 Width of vertical groove w3 Width of corner 32

Claims (20)

The mouth,
Shoulder and
The torso,
Having a bottom and
The trunk is
A plurality of walls,
A corner portion connecting the wall portions,
In the plastic bottle in which the wall portion is divided into an upper wall portion and a lower wall portion,
The wall portion has a rib extending in an arbitrary direction,
The upper wall portion includes a pressure absorbing panel that is recessed in one step,
A plurality of the ribs of the upper wall portion extend in the horizontal direction of the pressure absorbing panel,
The lower wall portion is
In the horizontal direction, from both ends of the wall portion toward the center, curved inward of the plastic bottle ,
A plastic bottle, wherein the plastic bottle is curved inward in the vertical direction from the upper and lower ends of the lower wall portion toward an intermediate point . 2. The plastic bottle according to claim 1 , wherein a plurality of the ribs intersect with each other, and the intersection is located on a line extending in the vertical direction about the horizontal center of the wall portion. 2. The plastic according to claim 1 , wherein a plurality of the ribs intersect with each other, and the intersection is located near the center of at least one surface of the upper wall portion and the lower wall portion. Bottle. The ribs of the upper wall part and / or the lower wall part are convex, and the convex ribs do not protrude outward of the plastic bottle from the surface connecting the both ends. The plastic bottle according to any one of claims 1 to 3 . Said ribs of said upper wall, a plastic bottle according to any one of claims 1 to 3, characterized in that a concave ribs. The rib of the lower wall portion is a plurality of groove portions extending in a horizontal direction between the both end portions of the lower wall portion, according to any one of claims 1 to 3, or 5 . Plastic bottle. The plastic bottle according to claim 6 , further comprising an annular circumferential groove that crosses the wall portion and the corner portion between the upper wall portion and the lower wall portion. The plastic bottle according to any one of claims 6 to 7 , wherein the corner portion has a longitudinal groove extending in a longitudinal direction. The depth of the longitudinal groove is greater than the depth of the annular circumferential groove that is provided between the upper wall portion and the lower wall portion and crosses the wall portion and the corner portion. The plastic bottle according to claim 8 . The plastic bottle according to any one of claims 6 to 9 , further comprising a first chamfered portion that is chamfered between the corner portion of the trunk portion and the shoulder portion. The plastic bottle according to any one of claims 6 to 10 , further comprising a second chamfered portion that is chamfered between the corner portion of the trunk portion and the bottom portion. The vertical groove extending in the vertical direction of the corner portion is characterized in that it extends below both ends of the groove portion at the lowest end of the plurality of groove portions extending in the horizontal direction between the both end portions. The plastic bottle according to any one of claims 8 to 11 . The grooves located on the lower side of the plurality of grooves, towards the center from the both ends of the wall portions, one of claims 6 to 12, characterized in that an arc-shaped curved downward Item 1. A plastic bottle according to item 1. Below the lowermost groove portion, there is another groove portion located below the vertical groove extending in the longitudinal direction of the corner portion, and both ends of the other groove portion are the both ends of the wall portion. The plastic bottle according to claim 12 , wherein the plastic bottle does not extend to a portion. The plastic bottle according to any one of claims 6 to 14 , wherein the groove portion has the largest depth at the center. The plastic bottle according to any one of claims 8 to 15 , wherein a depth of a longitudinal groove extending in a vertical direction of the corner portion is larger than a depth at the center of the groove portion. . An annular circumferential groove provided between the upper wall portion and the lower wall portion and crossing the wall portion and the corner portion is widened from the both end portions of the wall portion toward the center. plastic bottle according to any one of claims 7 to 16, characterized in that it is formed. The shoulder is connected to the wall and the corner,
The plastic bottle according to any one of claims 1 to 17 , wherein the shoulder connected to the wall is formed by four panels divided in a horizontal direction and a vertical direction. 19. The ratio of the amount of curvature at the center of the wall portion to the width between the both end portions of the wall portion is 0.01 or more and 0.2 or less. 19. Plastic bottle as described in. The ratio of the height from the ground contact surface of the bottom part to the annular circumferential groove across the wall part and the corner part provided between the upper wall part and the lower wall part, and the total height of the plastic bottle The plastic bottle according to any one of claims 7 to 19 , wherein is 0.3 or more and 0.8 or less.

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