Synthetic resin bottle

Abstract

To create a synthetic resin bottle improved in the stability of self-standing by preventing a wavy shape from occurring in a grounded part without lowering buckling strength.SOLUTION: A synthetic resin bottle includes a bottom 5 formed with a heel 6 that comprises radially outside an upper heel portion 6A formed having a convex curved surface with a predetermined first radius of curvature R1 and a lower heel portion 6B having a convex curved surface with a predetermined second radius of curvature R2 and continuing downward from the upper heel portion 6A and a bottom wall 7 that comprises a grounded part 9 and continues to a lower end 6c of the lower heel portion 6B. In a manner extending over the upper and lower heel portions 6A, 6B, a plurality of recesses 8 are formed depressed radially inward and arranged at an equal center angle circumferentially, so as to set up a height dimension H in a vertical direction from a recess lower end 8c to the grounded part 9 in a range of 0.2-2.0 mm and furthermore form the second radius of curvature R2 equal to or smaller than 1 / 10 of the first radius of curvature R1.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a synthetic resin bottle. [Background technology]

[0002] There is known a synthetic resin bottle (plastic bottle) that has multiple reinforcing grooves formed in the heel portion as a means of increasing the buckling strength and preventing deformation of the heel portion when a load is applied from above or below (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-203409 A Summary of the Invention [Problem to be solved by the invention]

[0004] The synthetic resin bottle described in Patent Document 1 has a configuration in which multiple reinforcing grooves 36, 37 consisting of vertical grooves (concave shapes) are arranged radially adjacent to the ground contact portion 32. However, these multiple reinforcing grooves 36, 37 can cause the ground contact portion 32 to have a wavy shape (wave shape), which can easily reduce the stability of the bottle when standing on its own.

[0005] In particular, in relatively large bottles of 1 liter or more made of PET resin or the like, the center of gravity of the bottle is formed at a relatively high position due to the weight reduction caused by the reduction in the amount of molding resin used, and therefore the bottle tends to tip over more easily on a conveying line where filling is performed using a belt conveyor or the like. Therefore, when a wavy shape occurs in the ground contact portion as described above, there is a problem that the bottle is more likely to tip over.

[0006] The present invention aims to solve the problems in the conventional technology described above by creating a synthetic resin bottle that prevents the formation of a wavy shape in the contact area and improves its self-supporting stability without reducing the buckling strength. [Means for solving the problem]

[0007] Among the means for solving the above problems, the first means of the present invention is A synthetic resin bottle having a body connected to a bottom and a neck portion extending upward from an upper end of the body via a shoulder portion, the bottom portion is formed with a heel portion including an upper heel portion formed with a convex curved surface of a predetermined first radius of curvature on the radially outer side and a lower heel portion connected to the lower side of the upper heel portion and having a convex curved surface of a predetermined second radius of curvature; and a bottom wall including a ground contact portion connected to a lower end of the lower heel portion, A plurality of recesses are formed so as to extend across the upper heel portion and the lower heel portion, the recesses being recessed radially inward and aligned at equal central angles in the circumferential direction, The height dimension in the vertical direction from the bottom end of the recess to the grounding portion is set in the range of 0.2 to 2.0 mm, Furthermore, the second radius of curvature is formed to be 1 / 10 or less of the first radius of curvature.

[0008] The second means of the present invention is the above-mentioned first means plus a means in which, when the vertical height dimension between the upper end of the upper heel portion and the boundary between the upper heel portion and the lower heel portion is L1, and the vertical height dimension between the boundary portion and the lower end of the lower heel portion, which is also the ground contact portion, is L2, L2 / L1 is 25% or less.

[0009] The third aspect of the present invention is the above-mentioned first or second aspect, further comprising the addition that the length between the lower end of the recess and the ground contact portion and along the outer surface of the lower heel portion is set in the range of 1.0 to 4.0 mm.

[0010] The fourth means of the present invention is the above-mentioned first to third means plus a means in which the recess is formed having a central concave bottom wall portion and a frame-shaped concave inclined wall surrounding the central concave bottom wall portion that is inclined toward the concave bottom wall portion.

[0011] The fifth means of the present invention is the above-mentioned fourth means plus a means in which the width dimension of the concave bottom wall portion at an intermediate height position is greater than the width dimension of the concave inclined wall at the same height position as the intermediate height position and is less than three times the width dimension of the concave inclined wall. Effect of the Invention

[0012] The synthetic resin bottle of the present invention can prevent the occurrence of wavy shapes in the contact portion and improve the self-supporting stability without reducing the buckling strength. [Brief description of the drawings]

[0013] [Figure 1] 1 is a front view of a synthetic resin bottle showing an embodiment of the present invention. [Diagram 2] 1A is an enlarged view showing a heel portion of a synthetic resin bottle, and FIG. 1B is a bottom view of the synthetic resin bottle. [Diagram 3] FIG. 3 is an enlarged view of part III in FIG. [Figure 4] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a synthetic resin bottle 1 that allows for improved self-supporting stability without reducing buckling strength will be described with reference to the drawings. FIG. 1 is a front view of a synthetic resin bottle showing an embodiment of the present invention, FIG. 2(a) is an enlarged view showing the heel portion of the synthetic resin bottle, FIG. 2(b) is a bottom view of the synthetic resin bottle, FIG. 3 is an enlarged view showing the heel portion, and FIG. 4 is a partial enlarged view showing a recess formed in the heel portion. In the following, the direction along the bottle axis O will be referred to as the axial direction, the up-down direction or the height direction, the direction perpendicular to the bottle axis O will be referred to as the radial direction, and the direction circumferentially around the bottle axis O will be referred to as the circumferential direction.

[0015] The synthetic resin bottle 1 (hereinafter simply referred to as "bottle 1") shown in this embodiment is a blow-molded product made of PET (polyethylene terephthalate) and is configured with a mouth 2 that is erected from the upper end of a body 4 that is connected to a bottom 5 via a tapered cylindrical shoulder 3, and is a round bottle container with a total height of 256 mm, a maximum diameter of the body 4 of 80 mm, a weight of 26 g, and a capacity of 1000 ml, for example. The blow molding may be, for example, biaxial stretch blow molding or extrusion blow molding, and the synthetic resin material from which the bottle 1 is molded is not limited to polyester resin such as PET, but may be other polyolefin resins such as polypropylene and polyethylene, etc. The bottle 1 may have a single-layer structure or a laminated structure.

[0016] The contents contained in the bottle 1 are not limited to foods such as soft drinks and seasonings, but may be, for example, lotions, detergents, medicines, etc. Furthermore, the contents are not limited to liquids, but may be powders or granules.

[0017] The mouth portion 2 has a cylindrical shape centered on the bottle axis O, and its outer surface is formed with an annular protrusion 2a for engaging a cap (not shown) by plugging, and a neck ring 2b is formed below the annular protrusion 2a.

[0018] The shoulder portion 3 is formed so as to expand in diameter downward from the lower end of the nozzle portion 2, and a cylindrical body portion 4 is connected to the lower end of the shoulder portion 3. The shape of the body 4 can be divided into three parts: an upper body 4A, a middle body 4B, and a lower body 4C. Four circumferential grooves 4a that function as reinforcing circumferential ribs are formed in the side wall of the upper body 4A, and five circumferential grooves 4a are also formed in the side wall of the lower body 4C. A gripping portion 4b formed in a reduced diameter is provided in the middle body 4B.

[0019] As shown in FIG. 2(a), the bottom portion 5 is configured to have a heel portion 6 that gradually reduces in diameter downward from the lower end of the lower body portion 4C, and a bottom wall 7 that is connected to the lower end thereof. 2(b), a ring-shaped grounding portion 9 is disposed on the periphery of the bottom wall 7, and a depressed bottom 10 is formed in the center of the bottom wall 7, which is depressed toward the inside of the bottle 1 with the grounding portion 9 as its base end. The depressed bottom 10 has a plurality of (six in this embodiment) radial ribs 11 arranged radially at equal central angles (60 degrees in this embodiment) and protruding toward the outside (downward) of the bottle 1. Such depressed bottom 10 and radial ribs 11 prevent the bottom wall 7 from bulging and deforming downward under pressure, for example, during high-temperature filling.

[0020] Heel portion 6 is formed with a curved surface that is convex on the radially outward side. More specifically, as shown in Fig. 3, heel portion 6 is formed with an upper heel portion 6A formed with a convex curved surface with a predetermined first radius of curvature R1 (the first radius of curvature R1 is preferably 70 to 100 mm, and is 80 mm in this embodiment), and a lower heel portion 6B formed with a convex curved surface with a predetermined second radius of curvature R2 (3 mm in this embodiment) that is 1 / 10 or less of the upper heel portion 6A, between the lower end of the upper heel portion 6A and the bottom wall 7, is connected to the lower heel portion 6B.

[0021] When the vertical height dimension between the upper end 6a of the upper heel portion 6A formed with the first radius of curvature R1 and the boundary portion 6b between the upper heel portion 6A and the lower heel portion 6B is taken as L1, and the vertical height dimension between the boundary portion 6b and the lower end 6c of the lower heel portion 6B, which is also the ground contact portion 9, is taken as L2, L2 / L1 is preferably 25% or less, and more preferably 15% or less. In this embodiment, the height dimension L1 is 15.7 mm, the height dimension L2 is 2.35 mm, and L2 / L1 is set to 14.6%.

[0022] 1 to 3, a plurality of recesses 8 are formed in the bottom 5, which are recessed radially inward and spaced apart at equal central angles (20 degrees in this embodiment) in the circumferential direction, so as to straddle the upper heel portion 6A and the lower heel portion 6B. The recesses 8 function as reinforcing ribs. 4, the recess 8 is formed with a central recessed bottom wall portion 8a and a frame-shaped recessed inclined wall 8b provided around the central recessed bottom wall portion 8a. The lower end of the recessed bottom wall portion 8a and the lower end of the recessed inclined wall 8b form a common recess lower end 8c and are located in the lower heel portion 6B.

[0023] Here, if the recess 8 is too far from the ground contact portion 9, it becomes difficult to obtain a reinforcing effect that prevents a decrease in buckling strength. For this reason, the height dimension H in the vertical direction between the recess bottom end 8c and the ground contact portion 9 is preferably in the range of 0.2 to 2.0 mm. Also, as shown in Fig. 3, when the height H is defined as the length L3 between the recess bottom end 8c and the ground contact portion 9 and along the outer surface of the lower heel portion 6B, it is preferable that L3 = 1.0 to 4.0 mm, and more preferably L3 = 1.2 to 2.0 mm.

[0024] As shown in FIG. 4, the width dimension of the concave bottom wall 8a at the intermediate height position is defined as W1, and the width dimension of the concave inclined wall 8b at the same height position is defined as W2. If the depth dimension of the recess 8 in the recessed direction (inward radial direction) is constant (for example, 0.5 mm), if the width dimension W1 is equal to or smaller than the width dimension W2, the inclination angle of the slope forming the concave bottom wall 8a becomes too steep, and the formability is likely to decrease. On the other hand, if the width dimension W1 is three times or more than the width dimension W2, the effect as a reinforcing rib is likely to decrease. For this reason, it is preferable that the width dimension W1 of the concave bottom wall 8a is larger than the width dimension W2 of the concave inclined wall 8b and is less than three times the width dimension W2 (W2×3>W1>W2). Furthermore, the number of recesses 8 is preferably 12 to 24, and is set to 18 in this embodiment. The depth of the recess 8 is preferably 0.3 to 1.0 mm (0.5 mm in this embodiment). If the depth is less than 0.3 mm, the effect as a reinforcing rib is likely to decrease, and if the depth exceeds 1.0 mm, the formability decreases.

[0025] In bottle 1 having the above-mentioned configuration, grounding portion 9 is arranged in a ring shape on bottom wall 7 and away from multiple recesses 8, which makes it difficult for the grounding portion 9 to have a wavy shape caused by multiple recesses 8. This ensures the self-supporting stability of bottle 1 without reducing buckling strength, and as a result, it becomes possible to prevent bottle 1 from falling over on a conveying line during a filling process or the like.

[0026] Although the configuration and the effects of the present invention have been described above based on the embodiments, the present invention is not limited to the above embodiments.

[0027] For example, in the above embodiment, a configuration in which a plurality of circumferential grooves are arranged on the body portion 4 has been shown and explained, but a configuration in which a vacuum absorption panel is arranged on the body portion 4 may also be used.

[0028] Although the above embodiment has been described with reference to a round bottle, a square bottle may also be used. [Industrial Applicability]

[0029] The present invention can expand the range of applications of lightweight synthetic resin bottles into even wider areas. [Explanation of symbols]

[0030] 1: Plastic bottle 2: Mouth part 2a: Annular protrusion 2b: Neck ring 3:Shoulder 4: Torso 4A: Upper torso 4B: Middle torso 4C: Lower torso 4a: Peripheral groove 4b: Grip part 5: Bottom 6: Heel 6A: Upper heel 6B: Lower heel 6a: Top of the lower heel 6b: Boundary part 6c: Bottom end of the lower heel 7: Bottom wall 8: Recess 8a: Concave bottom wall 8b: Concave slope wall 8c: Bottom end of recess 9: Grounding part 10: Bottom of the depression 11: Radial rib H: Height dimension L1: The vertical height between the upper heel and the boundary L2: The vertical height between the boundary and the bottom of the lower heel L3: Length along the outer surface between the bottom of the recess and the ground contact area O: Bottle stem R1: 1st radius of curvature R2: Second radius of curvature W1: Width of the concave bottom wall W2: Width of concave wall

Claims

1. A synthetic resin bottle having a body (4) connected to a bottom (5) and a neck (2) standing upright at the upper end of the body (4) via a shoulder (3), the bottom portion (5) is formed with a heel portion (6) including an upper heel portion (6A) formed with a convex curved surface of a predetermined first radius of curvature (R1) on the radially outer side and a lower heel portion (6B) connected to the lower side of the upper heel portion (6A) with a convex curved surface of a predetermined second radius of curvature (R2); and a bottom wall (7) including a ground contact portion (9) connected to a lower end (6c) of the lower heel portion (6B), A plurality of recesses (8) are formed so as to extend across the upper heel portion (6A) and the lower heel portion (6B), the recesses (8) being recessed radially inward and aligned at equal central angles in the circumferential direction, A height dimension (H) in the vertical direction from the lower end (8c) of the recessed portion to the ground contact portion (9) is set in the range of 0.2 to 2.0 mm, The synthetic resin bottle is further characterized in that the second radius of curvature (R2) is formed to be 1 / 10 or less of the first radius of curvature (R1).

2. 2. The synthetic resin bottle according to claim 1, wherein L2 / L1 is 25% or less, where L1 is the vertical height dimension between the upper end (6a) of the upper heel portion (6A) and the boundary portion (6b) between the upper heel portion (6A) and the lower heel portion (6B), and L2 is the vertical height dimension between the boundary portion (6b) and the lower end (6c) of the lower heel portion (6B), which is also the ground contact portion (9).

3. 3. A synthetic resin bottle according to claim 1 or 2, wherein a length (L3) between the lower end (8c) of the recess (8c) and the ground contact portion (9) along the outer surface of the lower heel portion (6B) is set in the range of 1.0 to 4.0 mm.

4. 2. The synthetic resin bottle according to claim 1, wherein the recess (8) is formed to have a central recessed bottom wall portion (8a) and a frame-shaped recessed inclined wall (8b) disposed around the central recessed bottom wall portion (8a) and inclined toward the recessed bottom wall portion (8a).

5. 5. A synthetic resin bottle as described in claim 4, wherein the width dimension (W1) of the concave bottom wall portion (8a) at an intermediate height position is greater than the width dimension (W2) of the concave inclined wall (8b) at the same height position as the intermediate height position and is less than three times the width dimension (W2) of the concave inclined wall (8b).

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