JP2025034340A - Plastic bottles - Google Patents

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

The present invention relates to a synthetic resin bottle.

There is a known 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).

JP 2013-203409 A

The synthetic resin bottle described in Patent Document 1 has a configuration in which multiple reinforcing grooves 36, 37 made of vertical grooves (concave shapes) are provided radially adjacent to the ground contact portion 32, but 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.

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 achieved by reducing the amount of molding resin used, and the bottle tends to tip over more easily on a conveying line where filling is performed using a conveyor belt or the like. For this reason, when a wavy shape occurs in the contact area as described above, there is a problem that the bottle is even more likely to tip over.

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

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 ground contact portion is set in the range of 0.2 to 2.0 mm,
Further, the second radius of curvature is set to 1/10 or less of the first radius of curvature.

The second aspect of the present invention is the above-mentioned first aspect, plus a further aspect in which, when the vertical height dimension between the top 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 bottom end of the lower heel portion, which is also the ground contact portion, is L2, L2/L1 is 25% or less.

The third aspect of the present invention is the above-mentioned first or second aspect, with the addition that the length between the bottom 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.

The fourth aspect of the present invention is the above first to third aspects, with the addition that the recess is formed with a central concave bottom wall portion and a concave inclined wall that is frame-shaped and inclined toward the concave bottom wall portion around the central concave bottom wall portion.

The fifth aspect of the present invention is the fourth aspect, plus the addition of a width dimension of the concave bottom wall at an intermediate height position that is greater than the width dimension of the concave inclined wall at the same height position as the intermediate height position, but less than three times the width dimension of the concave inclined wall.

The synthetic resin bottle of the present invention can prevent the formation of wavy shapes in the contact area and improve the self-supporting stability without reducing the buckling strength.

1 is a front view of a synthetic resin bottle showing an embodiment of the present invention. FIG. 2A is an enlarged view showing a heel portion of a synthetic resin bottle, and FIG. 2B is a bottom view of the synthetic resin bottle. FIG. 3 is an enlarged view of part III in FIG. FIG.

Hereinafter, an embodiment of a synthetic resin bottle 1 that can improve the self-supporting stability without reducing the 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 going around the bottle axis O will be referred to as the circumferential direction.

The synthetic resin bottle 1 shown in this embodiment (hereinafter simply referred to as "bottle 1") 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 for molding the bottle 1 is not limited to polyester resin such as PET, but may be other polyolefin resin such as polypropylene or polyethylene, etc. The bottle 1 may have a single layer structure or a laminated structure.

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, etc.

The nozzle 2 has a cylindrical shape centered on the bottle axis O, and its outer circumferential 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.

The shoulder portion 3 is formed so as to expand in diameter downward from the lower end of the nozzle 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, and 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. The middle body 4B is provided with a gripping portion 4b that is formed into a reduced diameter.

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 of the heel portion 6.
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 from the grounding portion 9. 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 downward under pressure, for example, during high-temperature filling.

The heel portion 6 is formed with a curved surface that is convex radially outward. More specifically, as shown in FIG. 3, the heel portion 6 is formed with an upper heel portion 6A formed with a convex curved surface of 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 of 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.

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 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 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%.

1 to 3, a plurality of recesses 8 are formed in the bottom portion 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 and inclined toward the 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.

If the recess 8 is too far from the ground contact portion 9, it becomes difficult to obtain the reinforcing effect that prevents a decrease in buckling strength. For this reason, the height dimension H in the vertical direction between the bottom end 8c of the recess 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 dimension H is defined as the length L3 between the bottom end 8c of the recess and the ground contact portion 9 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.

As shown in FIG. 4, the width dimension at the mid-height position of the concave bottom wall portion 8a 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 in the recessed direction (inward radial direction) of the recess 8 is constant (e.g., 0.5 mm), if the width dimension W1 is equal to or less than the width dimension W2, the inclination angle of the slope forming the concave bottom wall portion 8a becomes too steep, and the formability tends 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 tends to decrease. For this reason, it is preferable that the width dimension W1 of the concave bottom wall portion 8a is greater than the width dimension W2 of the concave inclined wall 8b and 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.

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

The configuration and effects of the present invention have been described above using examples, but the present invention is not limited to the above examples.

For example, in the above embodiment, a configuration in which multiple circumferential grooves are arranged on the body 4 is shown and described, but a configuration in which a vacuum absorption panel is arranged on the body 4 may also be used.

In addition, although the above embodiment shows a round bottle, a square bottle may also be used.

The present invention will enable the expansion of applications in the field of lightweight synthetic resin bottles to a wider range of areas.

1: synthetic resin bottle 2: mouth tube portion 2a: annular convex portion 2b: neck ring 3: shoulder portion 4: body portion 4A: upper body portion 4B: middle body portion 4C: lower body portion 4a: circumferential groove 4b: grip portion 5: bottom portion 6: heel portion 6A: upper heel portion 6B: lower heel portion 6a: upper end of lower heel portion 6b: boundary portion 6c: lower end of lower heel portion 7: bottom wall 8: recess 8a: recessed bottom wall portion 8b: recessed inclined wall 8c: recessed lower end 9: ground contact portion 10: sunken bottom portion 11: radial rib H: height dimension L1: vertical height dimension L2 between upper heel portion and boundary portion: vertical height dimension L3 between boundary portion and lower end of lower heel portion: length O along the outer surface between the lower end of the recess and the ground contact portion: bottle axis R1: first radius of curvature R2 : second radius of curvature W1 : width dimension of concave bottom wall portion W2 : width dimension of concave inclined wall

Claims (5)

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 below the upper heel portion (6A) with a convex curved surface of a predetermined second radius of curvature (R2); and a bottom wall (7) having 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. 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).
The synthetic resin bottle according to claim 1 or 2, wherein the length (L3) between the lower end of the recess (8c) and the ground contact portion (9) and along the outer surface of the lower heel portion (6B) is set in the range of 1.0 to 4.0 mm. The synthetic resin bottle according to claim 1, wherein the recess (8) is formed with a central recessed bottom wall portion (8a) and a frame-shaped recessed inclined wall (8b) that is inclined toward the recessed bottom wall portion (8a) around the recessed bottom wall portion (8a). The synthetic resin bottle according to claim 4, wherein the width dimension (W1) of the concave bottom wall portion (8a) at the 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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