Anti-foam bottom of plastic bottle

Abstract

To provide a foaming prevention bottom of a plastic bottle, which is prevented from foaming when filling a tilted and supported plastic bottle with a liquid using a rotary filling device.SOLUTION: The bottom part 40 includes a flat surface 42 at the center of the bottom part 40, a grounding part 41 located at a peripheral edge of the bottom part 40, and a connecting part 43 connected from an outer peripheral edge 42d of the flat surface 42 to an inner peripheral edge 41a of the grounding part 41. The connecting part 43 has a plurality of inclined parts 44a, 44b, 44c whose vertical cross part orthogonal to a bottle axis 11 is inclined stepwise downward from the outer peripheral edge 42d of the flat surface 42 toward the grounding part 41. The inclined parts 44a, 44b, 44c are substantially arc-shaped inclined surfaces that are recessed downward. The inclined surface does not project below a horizontal plane including the outer peripheral edges of the inclined parts 44a, 44b, 44c, and a flat part 45 is provided between the adjacent inclined parts 44a, 44b, 44c.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a bottom for a plastic bottle, and more particularly to a bottom for preventing foaming of a plastic bottle when a liquid is filled into a plastic bottle supported at an angle using a rotary filling device. [Background technology]

[0002] As is well known, bottle-shaped containers, such as plastic bottles, are widely used as containers for storing liquid contents, such as various beverages, etc. As a method for filling such bottle-shaped containers with liquid contents, a rotary filling device that rotates a cylindrical drum-shaped filling machine at high speed to increase production efficiency is known. In a rotary filling device, the liquid is discharged from the filling nozzle and filled into the container while the disk is rotating, so that the liquid column is deflected outward from the rotor by centrifugal force and lands on the outside of the bottom of the container. In the case where the bottom of the container is formed in a convex shape in the center and a concave shape on the outer periphery, there is a problem that when the filled liquid directly hits the concave shape on the outside, it splashes up significantly and causes a large amount of foaming.

[0003] Therefore, a rotary filling device that suppresses foaming during filling has been proposed (see Patent Document 1). In this rotary filling device, in order to drop the liquid at the center of the bottom of the container, the container holder supports the container so that the container is tilted downward toward the outer periphery of the disk at an inclination angle θ with respect to the discharge direction of the liquid discharged vertically downward from the filling nozzle. Note that this inclination angle θ is generally a value determined by the diameter of the rotation path of the filling valve of the rotary filling device, the production capacity (the number of containers that can be filled with liquid per minute), the number of filling valves, and the like, and is known to be about 3 to 6 degrees.

[0004] However, because the measures taken in the rotary filling device described above were insufficient to prevent foaming from spilling over the mouth of the container when the content liquid is filled up to the mouth of the container, and to prevent the mouth from becoming dirty, it was necessary to increase the head space (remaining air space) S (see Figure 8 (b)). If this head space S is large, oxidation of the content liquid will be promoted and the content liquid will appear to be small, so measures to prevent foaming and further reduce the head space S must also be taken into account in the structure of the container to be filled.

[0005] As a solution to this problem, for example, the bottom structure of a container has been proposed in Patent Document 2. In the bottom structure of a container in Patent Document 2, the lower end of the body that constitutes the outer peripheral wall of the container is closed by a bottom. This bottom includes a grounding portion formed in an annular shape and a convex portion formed at the center position within the grounding portion. An annular convex portion is formed between the grounding portion and the convex portion, and an annular concave portion is formed adjacent to the annular convex portion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2006-248547 A [Patent Document 2] JP 2015-205726 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology described in Patent Document 2 attempts to prevent splashing and foaming by reducing the force of the flow of the contents as it passes over the annular convex portion and collides with the body, thereby suppressing splashing. However, there is a concern that the contents may rise up the slope of the annular convex portion and branch toward the inner wall of the body and toward the ground, and that the contents that branch toward the inner wall of the body may collide with the inner wall of the body along the slope of the annular convex portion and be splashed up, resulting in increased foaming.

[0008] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a foam-preventing bottom for a plastic bottle, which prevents foaming when a plastic bottle supported at an angle is filled with liquid using a rotary filling device. [Means for solving the problem]

[0009] In order to solve the above problems, the foam-preventing bottom of the plastic bottle of the present invention has a bottom having a flat surface in the center of the bottom, a grounding portion located on the periphery of the bottom, and a connecting portion connecting the outer periphery of the flat surface to the inner periphery of the grounding portion, the connecting portion including a first inclined portion that inclines from the flat surface toward the grounding portion via a first step portion, a second inclined portion that inclines from the first inclined portion toward the grounding portion via a second step portion, and a third inclined portion that is continuous with the second inclined portion and extends toward the grounding portion. a third inclined portion inclined from the flat portion through a third step portion toward the ground contact portion, the first inclined portion, the second inclined portion, and the third inclined portion are inclined surfaces having a generally arcuate shape recessed downward, the inclined surface does not bulge downward from a horizontal plane including an outer periphery of the first inclined portion, the second inclined portion, or the third inclined portion, the radial length of the first inclined portion is greater than the radial lengths of the second inclined portion and the third inclined portion, and the radial length of the flat portion is but The length of the third inclined portion in the radial direction is greater than the length of the third inclined portion in the radial direction. This includes the structure The height of the first inclined portion in the bottle axial direction is greater than the heights of the second inclined portion and the third inclined portion in the bottle axial direction, and a connecting portion between the second inclined portion and the flat portion is recessed downward in a V-shape. The flat surface is formed so that a ratio D1 / D2 of a diameter D1 of the flat surface to a maximum diameter D2 of the body portion connected above the bottom portion is 0.05 to 0.30. It is characterized by the above.

[0010] Furthermore, the flat surface has a ratio D1 / D2 of a diameter D1 of the flat surface to a maximum diameter D2 of a body portion connected above the bottom portion, 0.10 ~ 0.25 It is characterized in that it is formed so as to be.

[0011] Furthermore, A first inclined portion, the second inclined portion, and the third inclined portion The inclined part is the total height of the plastic bottle. Before Note The first inclined portion, the second inclined portion, or the third inclined portion The ratio of the height of the inclined portion to the axial direction of the bottle is 0.02 to 0.1 It is characterized in that it is formed so as to be.

[0012] Furthermore, an extension line of the grounding portion and ,before Note The first inclined portion, the second inclined portion, or the third inclined portion Maximum curvature of the inclined section The above The inclination angle between the tangent and the inclined surface is 20 ~ 50 It is a degree And It is characterized by: Effect of the Invention

[0013] According to the foam-preventing bottom of a plastic bottle of the present invention, the bottom has a flat surface in the center of the bottom, a ground contact portion located on the periphery of the bottom, and a connecting portion connecting the outer periphery of the flat surface to the inner periphery of the ground contact portion, the connecting portion having a first inclined portion that inclines from the flat surface toward the ground contact portion via a first step portion, a second inclined portion that inclines from the first inclined portion toward the ground contact portion via a second step portion, a plane portion that is continuous with the second inclined portion and extends toward the ground contact portion, and a third inclined portion that inclines from the plane portion toward the ground contact portion via a third step portion, the first inclined portion, the second inclined portion, and the third inclined portion are inclined surfaces that are recessed downward and have a substantially arc-shaped shape, the inclined surface does not bulge downward from a horizontal plane including the outer periphery of the first inclined portion, the second inclined portion, or the third inclined portion, the radial length of the first inclined portion is greater than the radial lengths of the second inclined portion and the third inclined portion, and the radial length of the plane portion is greater than the radial lengths of the second inclined portion and the third inclined portion. but The length of the third inclined portion in the radial direction is greater than the length of the third inclined portion in the radial direction. This includes the structure The height of the first inclined portion in the bottle axial direction is greater than the height of the second inclined portion and the third inclined portion in the bottle axial direction, and the connection portion between the second inclined portion and the flat portion is recessed downward in a V-shape. The flat surface is formed so that the ratio D1 / D2 of the diameter D1 of the flat surface to the maximum diameter D2 of the body portion connected above the bottom portion is 0.05 to 0.30. Therefore, when filling a liquid into a plastic bottle supported at an angle using a rotary filling device, the flow rate of the content liquid is gradually attenuated while flowing through the connecting portion, Since the liquid content passes through the grounded portion before colliding with the inner wall of the body, splashing is kept small and foaming can be prevented.

[0014] Furthermore, according to the foam-preventing bottom of the plastic bottle of the present invention, the flat surface has a diameter of The ratio D1 / D2 of D1 to the maximum diameter D2 of the body part connected above the bottom part is 0.10 ~ 0.25 Since the filling nozzle of a rotary filling device can be easily aligned, the liquid content can hit the flat surface once and the flow rate can be attenuated.

[0015] Furthermore, according to the foam-preventing bottom of the plastic bottle of the present invention, A first inclined portion, a second inclined portion, and a third inclined portion The slope is the total height of the plastic bottle. The first inclined portion, the second inclined portion, or the third inclined portion The ratio of the height of the inclined part to the bottle axis direction is 0.02 to 0.1 Since the flow rate of the content liquid is gradually attenuated while it flows through the connecting portion, it is possible to prevent bubbling.

[0016] Furthermore, according to the foam-preventing bottom of the plastic bottle of the present invention, an extension line of the grounding part and The first inclined portion, the second inclined portion, or the third inclined portion The inclination angle between the tangent line at the inclined surface of the maximum curvature of the inclined part and the 20 ~ 50 Since the flow rate of the content liquid is gradually attenuated as it flows through the connecting portion, bubbling can be prevented. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a front view showing an example of a plastic bottle equipped with a foam-preventing bottom according to the present embodiment. [Diagram 2] FIG. 2 is a plan view of the plastic bottle of FIG. [Diagram 3] FIG. 2 is a bottom view of the plastic bottle of FIG. [Figure 4] FIG. 3 is a view taken in the direction of the arrow I in FIG. 2. [Diagram 5]4(a) is a partially enlarged cross-sectional view taken along line II-II in FIG. 3, and (b) is a partially enlarged cross-sectional view taken along line III-III in FIG. [Figure 6] FIG. 5(b) is an enlarged partial cross-sectional view of FIG. [Figure 7] FIG. 1(a) is an image showing the flow of liquid when a plastic bottle according to the present embodiment is supported at an angle and filled with liquid using a rotary filling device, and FIG. 1(b) is an image showing the flow of liquid when a conventional plastic bottle is supported at an angle and filled with liquid using a rotary filling device. [Figure 8] 1A is a schematic diagram of a plastic bottle supported at an angle being filled with liquid using a rotary filling device, and FIG. 1B is a front view of the plastic bottle after filling with liquid has been completed. [Figure 9] FIG. 2 is an enlarged cross-sectional view taken along line IV-IV in FIG. [Figure 10] This is an enlarged partial cross-sectional view taken along line VV in Figure 1. The arrow direction indicates the outside of the plastic bottle. [Figure 11] 2 is an enlarged view of a circumferential groove portion of the plastic bottle of FIG. 1. [Figure 12] FIG. 2 is a schematic plan view illustrating a rotary filling device. [Figure 13] FIG. 2 is a front view of a plastic bottle of a comparative example. [Figure 14] FIG. 14 is a plan view of the plastic bottle of FIG. 13. [Figure 15] FIG. 14 is a bottom view of the plastic bottle of FIG. [Figure 16] 16 is an enlarged partial cross-sectional view taken along the line VI-VI in FIG. 15. [Figure 17] 1 is a modified example of a plastic bottle having a foam-preventing bottom according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the details of the embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a front view showing an example of a plastic bottle equipped with a foam-preventing bottom of a plastic bottle 1 according to this embodiment. Fig. 2 is a plan view of the plastic bottle 1 in Fig. 1, and Fig. 3 is a bottom view of the plastic bottle 1 in Fig. 1. Fig. 4 is a view seen from the direction of the arrow I in Fig. 2. Note that, for convenience of explanation, in the following description, the mouth 10 of the plastic bottle 1, where the contents are filled into the container, is considered to be upside down in the state shown in Fig. 1 in which the plastic bottle 1 is upright.

[0019] As shown in Figures 1 to 5, the foam-preventing bottom of the plastic bottle 1 according to this embodiment has a bottom 40 having a flat surface 42 in the center of the bottom 40, a ground portion 41 located on the periphery of the bottom 40, and a connecting portion 43 connecting from the outer peripheral edge 42d of the flat surface 42 to the inner peripheral edge 41a of the ground portion 41, and the connecting portion 43 has a plurality of inclined portions 44a, 44b, 44c in a vertical cross section perpendicular to the bottle axis 11 that inclines gradually downward from the outer peripheral edge 42d of the flat surface 42 toward the ground portion 41, and the inclined portions 44a, 44b, 44c are inclined surfaces that are approximately arc-shaped and recessed downward, and the inclined surfaces do not bulge downward from a horizontal plane including the outer peripheral edges of the inclined portions 44a, 44b, 44c, and a flat portion 45 is provided between adjacent inclined portions 44a, 44b, 44c.

[0020] In the following, a square bottle having a substantially rectangular horizontal cross section will be described in detail as an example of a suitable embodiment of the plastic bottle 1 according to this embodiment. There are no particular limitations on the bottle having the above-mentioned configuration of the bottom 40, except for the bottom shape, and it may be a round bottle having a circular cross section of the body of the container, or a square bottle having a substantially rectangular cross section of the body of the container.

[0021] The plastic bottle 1 according to this embodiment has a mouth 10, a shoulder 20, a body 30, and a bottom 40. The mouth 10 serves as an inlet for filling the contents, a pouring outlet, or a drinking spout, and the plastic bottle 1 is sealed by attaching a lid (not shown) to the mouth 10.

[0022] The upper side of the shoulder portion 20 is connected to the mouth portion 10, while the lower side is connected to the body portion 30. The shoulder portion 20 has a shape of a substantially square pyramid with a diameter expanding from the top to the bottom. As shown in FIG. 2, since the plastic bottle 1 is a rectangular bottle, the shoulder portion 20 is composed of four faces, namely, shoulder portion 20A, shoulder portion 20B, shoulder portion 20C, and shoulder portion 20D, in a clockwise direction. More specifically, the shoulder portion 20 has four shoulder wall portions 21 having the same shape, and a shoulder corner portion 22 is formed between adjacent shoulder wall portions 21. In the following, one face including the shoulder portion 20A will be described, and the symbols A to D will be appropriately assigned to the respective portions of the four faces in the circumferential direction as described above, as necessary.

[0023] The shoulder portion 20 and the torso portion 30 consist of a plurality of wall portions 51 and corner portions 52 connecting the wall portions 51, the wall portion 51 being divided into a shoulder wall portion 21 and a torso wall portion 31, the torso wall portion 31 being further divided into an upper torso wall portion 31E and a lower torso wall portion 31F, the corner portions 52 being divided into a shoulder corner portion 22 and a torso corner portion 32, and the torso corner portion 32 being further divided into an upper torso corner portion 32E and a lower torso corner portion 32F.

[0024] More specifically, shoulder 20 is connected to upper torso wall 31E and upper torso corner 32E. From the viewpoint of improving the strength of shoulder 20, shoulder wall 21 is preferably formed by two panels 21a, 21b divided in the vertical direction. From the viewpoint of improving the strength, it is preferable that the vertical division is on a line extending upward through the approximate center of wall 51 in the horizontal direction. On the other hand, shoulder corner 22 may be formed by a single panel.

[0025] Next, it is preferable to provide a plurality of vertical ribs 53 across the circumferentially extending ridge line 50 where the shoulder portion 20 transitions to the body portion 30, from the viewpoint of preventing so-called shoulder collapse, in which the portion near the ridge line 50 where the shoulder portion 20 transitions to the body portion 30 is dented due to an external impact, and from the viewpoint of increasing the vertical buckling strength. Also, from the viewpoint of appropriately exerting this effect, it is preferable that the vertical rib 53 is provided on a line extending in the vertical direction through approximately the horizontal center of the wall portion 51 and the corner portion 52.

[0026] In addition, the vertical rib 53 may be a groove shape having a V-shaped cross section in which the groove side surfaces intersect at a straight groove bottom 55, or may be a groove shape having a trapezoidal cross section having a groove bottom 55 of a predetermined width and groove side surfaces rising from both widthwise ends of the groove bottom 55, or may be a concave groove shape with an arc-shaped cross section.

[0027] With this configuration, when an external force is applied to the area near the ridge line 50 that extends in the circumferential direction and transitions from the shoulder portion 20 to the body portion 30, the area near the ridge line 50 is deformed as if it is being pushed inward of the bottle, and a fold line is generated in a direction perpendicular to the height direction. By providing the vertical rib 53 perpendicular to this fold line, a restoring force against such a shape change can be exerted, and permanent deformation can be suppressed in the vicinity of the ridge line 50 where the shoulder portion 20 of the plastic bottle 1 transitions to the body portion 30. In other words, shoulder collapse can be prevented and the buckling strength in the vertical direction can be increased.

[0028] Furthermore, the upper ends 54 of the vertical ribs 53 are preferably concave ribs provided at a position 0.5 to 4.0 mm above the ridge line 50 in the vertical direction. Furthermore, adjacent vertical ribs 53 in the circumferential direction of the wall portion 51 are preferably provided at equal intervals of 2 to 6 mm. Furthermore, the vertical ribs 53 of the wall portion 51 and the corner portion 52 are each provided with an odd number of vertical ribs 53, and in particular, it is preferable that the vertical ribs 53 of the wall portion 51 are each formed with 5 to 15 pieces.

[0029] Next, the body wall 31 of the plastic bottle 1 will be described in detail. The body wall 31 is preferably divided into an upper body wall 31E and a lower body wall 31F at approximately the middle in the vertical direction, each of which is provided with a pressure absorbing panel 35. The pressure absorbing panel 35 absorbs pressure changes, particularly decompression changes, inside the plastic bottle 1, and maintains the strength of the plastic bottle 1, particularly the side wall strength. The pressure absorbing panel 35 will be described below, but since the upper body wall 31E and the lower body wall 31F have the same configuration, only the lower body wall 31F will be described and a description of the configuration of the upper body wall 31E will be omitted.

[0030] As shown in Figures 1, 9 and 10, the pressure absorption panel 35 of the lower body wall portion 31F has a stepped body wall surface 33a that is recessed one step inward from the outermost surface of the lower body wall portion 31F, and a stepped body wall surface 33b that convexes one step outward from the stepped body wall surface 33a, and the panel inclined portion 34b is formed via a chamfered portion 37d so as to surround the periphery of the stepped body wall surface 33b, the stepped body wall surface 33a is formed via a chamfered portion 37c so as to surround the periphery of the panel inclined portion 34b, the panel inclined portion 34a is formed via a chamfered portion 37b so as to surround the periphery of the stepped body wall surface 33a, and the outermost surface of the lower body wall portion 31F is connected via a chamfered portion 37a so as to surround the periphery of the panel inclined portion 34a.

[0031] Depth s1 from the outermost surface of lower body wall portion 31F to corrugated body wall surface 33a is 0.5 to 4.0 mm, preferably 1.0 to 3.0 mm, and depth s2 from corrugated body wall surface 33b to corrugated body wall surface 33a is 0.2 to 3.0 mm, preferably 0.5 to 2.0 mm. There is a relationship between s1 and s2, s1>s2, and if depth s1 is small, it becomes difficult to absorb the load caused by changes in the internal pressure of plastic bottle 1, while if depth s1 is large, poor shaping and whitening due to overstretching are likely to occur during molding of plastic bottle 1.

[0032] Plastic bottle 1 has a small degree of oxygen permeability. If the contents are stored in plastic bottle 1 for a long period of time, oxidation will occur depending on the liquid contained therein, causing the pressure inside plastic bottle 1 to decrease. In addition, the pressure inside plastic bottle 1 will change depending on the temperature difference between when the contents are filled and when the contents are stored. Plastic bottle 1 that has experienced reduced pressure inside is pulled inward, causing deformation.

[0033] At this time, the pressure absorbing panel 35 easily deforms inward as the stepped body wall surfaces 33a, 33b are stretched. When the pressure inside the plastic bottle 1 is reduced, the pressure absorbing panel 35 recesses inward into the plastic bottle 1, thereby preventing the entire plastic bottle 1 from deforming. Furthermore, the stress applied to the plastic bottle 1 is dispersed by the uneven portions, increasing the rigidity of the wall surface 51, and preventing the bottle from bulging.

[0034] The pressure absorbing panel 35 also serves to prevent the entire plastic bottle 1 from deforming when the pressure inside the plastic bottle 1 is increased. The pressure absorbing panel 35 having this configuration can also prevent the wall of the plastic bottle 1 from being pressed inward when the plastic bottle 1 is opened, causing the contents to be pushed out from the mouth 10 and spill. The pressure absorbing panel 35 can also increase the rigidity of the body 30.

[0035] Here, if the panel of the stepped barrel wall surface 33b is a flat surface, the bottle will be significantly deformed when held. Therefore, it is preferable to have a plurality of horizontal ribs 36 extending horizontally over the entire area in the vertical direction from the upper end to the lower end of the panel of the stepped barrel wall surface 33b. As described above, it is preferable to have a plurality of horizontal ribs 36 extending horizontally within the panel surrounded by the stepped barrel wall surface 33b, but it is also possible to have concave or convex ribs (not shown) extending in any direction. Furthermore, the horizontal ribs 36 may be formed only in a part of the panel surrounded by the stepped barrel wall surface 33b, for example, only the upper half, the lower half, or the central part in the vertical direction.

[0036] However, if there are too many transverse ribs 36, the pressure absorbing panel 35 will be less likely to deform inwardly of the plastic bottle 1, and the pressure absorbing function will be lost. Therefore, the number and dimensions of the transverse ribs 36 are appropriately designed.

[0037] It is preferable that 4 to 10 transverse ribs 36 are provided within the panel surrounded by the stepped body wall surface 33b. By providing four or more transverse ribs 36, the vacuum absorbing function can be fully exerted, the rigidity of the body wall portion 31 is increased, the pressure applied to the plastic bottle 1 is dispersed, and the effect of preventing body bulging can be fully obtained. On the other hand, if the transverse ribs 36 are 11 or more, the vacuum absorbing function is impaired.

[0038] A label is attached to the upper body wall 31E of the plastic bottle 1. The label is attached by a shrink label, which is made by applying hot air to a cylindrical heat-shrinkable film such as polystyrene (PS) or polyethylene terephthalate (PET) that is placed over the plastic bottle 1 and shrinking the film. Since the dimensions of the cylindrical heat-shrinkable film are set to predetermined values, if the upper body wall 31E is bulging, problems occur in which the heat-shrinkable film becomes clogged or cannot be inserted.

[0039] Therefore, it is preferable that the pressure absorbing panel 35 is configured so as not to protrude outward from the outermost surface of the upper body wall 31E of the plastic bottle 1. In other words, it is preferable that the stepped body wall surface 33b is located inward from the outermost surface of the upper body wall 31E, and the horizontal rib 36 provided in the panel surrounded by the stepped body wall surface 33b is a concave rib. This allows the label to be attached smoothly to the upper body wall 31E, and also improves the loading efficiency of the boxing into cardboard boxes, etc., thereby improving productivity. Furthermore, by providing the pressure absorbing panel 35, the appearance of the product filled with the contents in the plastic bottle 1 can be maintained in good condition, and the product value can be prevented from decreasing.

[0040] The width a of the corrugated barrel wall surface 33a shown in Fig. 9 is preferably set to 0.5 mm ≦ a ≦ 5.0 mm. Since the corrugated barrel wall surface 33a has an uneven shape in the blow molding die, setting the width a to 0.5 mm ≦ a makes it easier to shape the corrugated barrel wall surface 33a during blow molding. On the other hand, setting the width a of the corrugated barrel wall surface 33a to a ≦ 5.0 mm allows the reduced pressure absorbing function and reinforcing function to be fully exerted.

[0041] It is preferable that the angles θ2 and θ1 of the panel inclined portions 34a and 34b are 15 degrees≦θ2≦60 degrees and 15 degrees≦θ1≦60 degrees from the viewpoints of blow moldability and releasability after molding. Note that θ2 and θ1 may all be set to the same value θ2=θ1.

[0042] In addition, in one pressure absorption panel 35, each dimension such as s1, s2, a, θ1, θ2, etc. can be appropriately designed with different values that satisfy the above-described relationships. Furthermore, the configuration of the pressure absorption panel 35 and the horizontal rib 36 of the lower body wall portion 31F described above can be arbitrarily combined with the configuration of the pressure absorption panel 35 and the horizontal rib 36 of the upper body wall portion 31E within a non-conflicting range.

[0043] Preferably, between the upper body wall portion 31E and the lower body wall portion 31F, as shown in FIG. 11, there is an annular circumferential groove 38 that crosses the body wall portion 31 and the body corner portion 32. The circumferential groove 38 improves the side wall strength that can withstand the horizontal load of the body portion 30.

[0044] Here, the configuration of the circumferential groove 38 will be described in detail. The circumferential groove 38 is formed to be wider from both ends of the body corner portion 32 toward the center. That is, the width c2 of the circumferential groove 38 at the center of the body corner portion 32 is larger than the width c1 of the circumferential groove 38 at both ends of the body corner portion 32. With this configuration, the rigidity of the body portion 30 can be increased.

[0045] The ratio of c2 / c1 is preferably 1.05 to 2.50 from the viewpoints of buckling strength and formability. If the ratio of c2 / c1 is less than 1.05, the effect of preventing stress concentration is difficult to be exerted. On the other hand, if the ratio of c2 / c1 is greater than 2.50, it will become a buckling point during vertical load.

[0046] The lower body wall portion 31F has a groove portion 39 that extends horizontally at a position below the pressure absorption panel 35 and close to the bottom portion 40, and both ends of the groove portion 39 do not extend to both ends of the wall portion 51. With this configuration, when the content liquid filled into the bottle from the mouth portion 10 hits the flat surface 42 of the bottom portion 40 described later and then flows from the flat surface 42 toward the grounding portion 41 and rises along the inner wall of the body portion, it contacts the groove portion 39 that is recessed inward at a position close to the bottom portion 40, thereby preventing foaming without becoming a large turbulent flow.

[0047] Next, the bottom 40 of the plastic bottle 1 will be described in detail with reference to Fig. 3 and Fig. 5. The bottom 40 includes a flat surface 42 at the center of the bottom 40, a grounding portion 41 located on the periphery of the bottom 40, and a connecting portion 43 connecting the outer peripheral edge 42d of the flat surface 42 to the inner peripheral edge 41a of the grounding portion 41. The connecting portion 43 has a plurality of inclined portions 44a, 44b, and 44c formed in a vertical section perpendicular to the bottle axis 11, the inclined portions 44a, 44b, and 44c being inclined downward in a stepwise manner from the outer peripheral edge 42d of the flat surface 42 toward the grounding portion 41. The inclined portions 44a, 44b, and 44c are inclined surfaces having a substantially arcuate shape recessed downward, and the inclined surfaces do not bulge downward from a horizontal plane including the outer peripheral edges of the inclined portions 44a, 44b, and 44c, and are characterized in that a flat portion 45 is provided between the adjacent inclined portions 44a, 44b, and 44c.

[0048] The periphery of the grounding portion 41 is substantially rectangular, and the short side of the rectangle is substantially arc-shaped. The shape of the periphery of the grounding portion 41 is not limited to this configuration, and may be, for example, a polygonal shape such as a hexagon, a circular shape, an elliptical shape, or the like.

[0049] The connecting portion 43 has three inclined stages: a first inclined portion 44a that inclines from the outer peripheral edge 42d of the flat surface 42 toward the grounding portion 41; a second inclined portion 44b that continues from the outer peripheral edge of the first inclined portion 44a and inclines toward the grounding portion 41; a flat portion 45 that continues from the outer peripheral edge of the second inclined portion 44b and extends toward the grounding portion 41; and a third inclined portion 44c that continues from the outer peripheral edge of the flat portion 45 and inclines toward the inner peripheral edge 41a of the grounding portion 41.

[0050] Here, the flat surface 42 is preferably formed in a range in which the ratio D1 / D2 of the diameter D1 of the flat surface 42 to the maximum diameter D2 of the body 30 is 0.05 to 0.30. If this range is too small, the area in which the liquid content W can reach becomes narrow, making it necessary to align the filling nozzle 2 in the rotary filling device 5 shown in Fig. 8(a) and Fig. 12, and the liquid content W is less likely to hit the flat surface 42, and once it hits the flat surface 42, the function of attenuating the flow rate is insufficient. If the formation range is too large, the range in which the content liquid W can reach will be wide, and the filling nozzle 2 can be easily positioned in the rotary filling device 5. However, the range of the connecting portion 43 will be narrow, and sufficient space cannot be secured to provide the three-stage inclined portions 44a, 44b, 44c or the flat portion 45. As the flow rate of the content liquid W does not decrease gradually as it flows through the connecting portion 43, it will collide with the inner wall of the body, making it impossible to suppress splashing and preventing foaming.

[0051] The flat surface 42 is preferably circular, but may be polygonal, such as a hexagon, or elliptical, depending on the size and shape of the bottle. As a modification of this embodiment, the flat surface 42 in the center of the bottom 40 may have an inverted dome-shaped recess 42e in the center, as shown in Fig. 17. With this configuration, the stretch rod used in blow molding the plastic bottle fits nicely into the inverted dome-shaped recess 42e, making it easier to mold the bottle.

[0052] Furthermore, as shown in Figures 5(a) and 5(b), the inclined portions 44a, 44b, 44c are formed so that the ratios H3 / H1, H4 / H1, H5 / H1 of the heights H3, H4, H5 of the first inclined portion 44a, the second inclined portion 44b, and the third inclined portion 44c in the direction of the bottle axis 11 to the total height H1 of the plastic bottle 1 are 0.02 to 0.25, which is preferable from the viewpoint of gradually reducing the flow rate of the content liquid W as it flows through the connecting portion 43 and preventing foaming.

[0053] 6, the inclination angles α, β, γ between the extension line of the ground contact portion 41 and the tangent line at the inclined surface of the maximum curved portion of the first inclined portion 44a, the second inclined portion 44b, and the third inclined portion 44c are preferably 15 to 60 degrees from the viewpoint of gradually attenuating the flow rate of the content liquid W while it flows through the connecting portion 43 to prevent foaming. Furthermore, it is more preferable that the inclination angles α, β, γ have a relationship of β≧α>γ. In the case of α>β>γ or α>β, there is no problem if the flow rate of the content liquid W during filling is fast, but if the flow rate is slow, the filling gradually catches up, the content liquid W becomes clogged, and excessive foaming occurs.

[0054] In addition, the heights H3, H4, H5 of the inclined portions 44a, 44b, 44c in the direction of the bottle axis 11 and the inclination angles α, β, γ of the tangents to the inclined surfaces of the maximum curved portions of the inclined portions 44a, 44b, 44c with respect to the extension line of the ground contact portion 41 can be designed appropriately taking into account the size of the bottle, etc.

[0055] Next, in the configuration of the bottom 40 of a conventional plastic bottle and the configuration of the bottom 40 of the plastic bottle of this embodiment, the flow of the content liquid W filled in the bottle supported so as to be inclined at an inclination angle θ toward the outer periphery of the wheel 7 (see FIG. 12) downward with respect to the discharge direction of the content liquid W discharged vertically downward from the filling nozzle 2 (see FIG. 8(a)) using the rotary filling device 5 will be described in detail. Note that this inclination angle θ is preferably about 3 to 6 degrees, and can be appropriately adjusted depending on the diameter of the rotation path of the filling valve 2 of the rotary filling device 5, the production capacity (the number of containers that can be filled with liquid per minute), the number of filling valves 2, and the like.

[0056] Here, as shown in Figures 7, 8 and 12, after the content liquid W hits the flat surface 42 of the bottom 40 of the bottle, it flows through the connecting portion 43 on the wheel axle 6 side from the tangent 42c of a circle 42b, which is the trajectory through the center 42a of the flat surface 42 of the bottle in the rotary filling device 5, toward the ground contact portion 41 (hereinafter referred to as "flowing inward"), and there is another case in which it flows through the connecting portion 43 on the opposite side to the wheel axle 6 side from the tangent 42c of the circle, toward the ground contact portion 41 (hereinafter referred to as "flowing outward").

[0057] As shown by the arrow in Figure 7(b), according to the configuration of bottom 40 of a conventional plastic bottle, the content liquid W flows along the curved shape of the entire bottom 40, and without slowing down in flow speed, it hits the inner wall of body 30 from ground contact part 41 and splashes upward in the bottle, causing large splashes and foaming. Note that because the bottle is supported at an inclination angle θ, when the liquid flows outward, the inclination is gentler than when the liquid flows inward, so the flow speed is slower and foaming is less likely to occur.

[0058] On the other hand, as shown by the arrow in FIG. 7(a), according to the configuration of the bottom 40 of the plastic bottle of this embodiment, when the liquid W flows inward, the liquid W hits the flat surface 42 of the bottom 40 of the bottle, which is inclined at an inclination angle θ, and then flows down the upper surface of the flat surface 42 toward the ground side. At the first step 46a, which is the boundary between the flat surface 42 and the first inclined portion 44a, the step acts as a dam, so that the liquid W is decelerated. Then, the liquid W further flows down the first inclined portion 44a and flows between the first inclined portion 44a and the second inclined portion 44b. The flow is decelerated at a second step 46b, which is the boundary between the first and second inclined portions 44a and 4b, by the step functioning as a dam, and then flows down the second inclined portion 44b, and the acceleration weakens as the flow flows through the flat portion 45, which has a gentler inclination than the second inclined portion 44b, and then at a third step 46c, which is the boundary between the flat portion 45 and the third inclined portion 44c, by the step functioning as a dam, and then flows down the third inclined portion 44c, and passes through the ground contact portion 41 at a flow velocity that is gradually attenuated, and collides with the inner wall of the body portion 30. Here, the step functions as a dam to attenuate the flow velocity because the bottle is tilted by the inclination angle θ when filled using the rotary filling device 5.

[0059] In addition, since the generally arc-shaped inclined surface recessed below the inclined portions 44a, 44b, 44c does not bulge below the horizontal plane including the outer periphery of the inclined portions 44a, 44b, 44c, the liquid contents W do not ascend the gradient of the inclined surface, but branch toward the inner wall of the body with the momentum of the ascending flow velocity and collide with the inner wall of the body, preventing the liquid contents W from increasing foaming due to splashing up. In other words, the liquid contents W passes through the grounding portion at a flow velocity that is gradually attenuated while flowing through the above-mentioned connecting portion 43, and then collide with the inner wall of the body, so that splashing can be kept small and foaming can be prevented.

[0060] Furthermore, since flat portions 45 are provided between adjacent inclined portions 44a, 44b, 44c, the flow rate of the content liquid can be further attenuated while flowing through connected portion 43. Therefore, it is possible to reduce foaming when filling plastic bottle 1 with the content liquid while maintaining the production speed, without lowering filling nozzle 2 or slowing down the production speed. Furthermore, by minimizing foaming during filling, the head space S of plastic bottle 1 can be reduced, and oxidation of the content liquid in plastic bottle 1 can also be suppressed.

[0061] Next, when the content liquid W flows outward, because the bottle is supported at an inclination angle θ, the inclination is gentler than when the content liquid W flows inward, resulting in a slower flow rate and less foaming.

[0062] 3 and 5, reinforcing ribs 48 are formed radially from the outer peripheral edge 42d of the flat surface 42 to the inner peripheral edge 41a of the ground contact portion 41 at the connecting portion 43 of the bottom portion 40. This makes it possible to prevent deformation, such as inversion of the bottom portion 40, caused by internal pressure generated by an impact such as a drop. EXAMPLES

[0063] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0064] <Material> [Examples 1 to 5] As Examples 1 to 5, the anti-foaming bottom of the plastic bottle 1 according to this embodiment shown in FIGS. 1, 3, and 5 was used. That is, for the anti-foaming bottom of the plastic bottle 1, the bottom 40 has a flat surface 42 at the center of the bottom 40, a grounding portion 41 located at the periphery of the bottom 40, and a connecting portion 43 connecting from the outer peripheral edge 42d of the flat surface 42 to the inner peripheral edge 41a of the grounding portion 41. The connecting portion 43 has a plurality of inclined portions 44a, 44b, 44c whose longitudinal section perpendicular to the bottle axis 11 inclines downward stepwise from the outer peripheral edge 42d of the flat surface 42 toward the grounding portion 41 side. The inclined portions 44a, 44b, 44c are substantially arc-shaped inclined surfaces that are recessed downward, and the inclined surfaces do not bulge below the horizontal plane including the outer peripheral edges of the inclined portions 44a, 44b, 44c, and a flat portion 45 is provided between adjacent inclined portions 44a, 44b, 44c. The plastic bottle 1 was made of polyethylene terephthalate, had a weight of 35 g, and a capacity of 750 ml. The plastic bottle 1 was produced by blow molding a preform. Note that no shaping defect occurred during blow molding.

[0065] The plastic bottles of Examples 1 to 5 had the above-described shape, and the ratio D1 / D2 of the diameter D1 of the flat surface 42 in each configuration of the bottom 40 to the maximum diameter D2 of the body portion 30, the ratios H3 / H1, H4 / H1, H5 / H1 of the height in the bottle axis direction of the inclined portions 44a, 44b, 44c to the overall height of the plastic bottle, and the inclination angles α, β, γ formed by the extension line of the grounding portion 41 and the tangent line on the inclined surface of the maximum curved portion of the inclined portions 44a, 44b, 44c were set as the numerical values in Table 1, and the evaluations described below were performed. Note that in the examples, the evaluation was performed using plastic bottles with a maximum diameter of 75 mm in the body portion of the plastic bottle.

[0066] [Comparative Example 1] A plastic bottle 100 for 750 ml having a configuration including a mouth portion 110, a shoulder portion 120, a body portion 130, and a bottom portion 140 shown in FIGS. 13 to 16 was tested as Comparative Example 1 of a plastic bottle having a conventional shape.

[0067] 13 is a front view of plastic bottle 100, FIG. 14 is a plan view of plastic bottle 100 in FIG. 13, FIG. 15 is a bottom view of plastic bottle 100 in FIG. 13, and FIG. 16 is an enlarged partial cross-sectional view of plastic bottle 100 along line VI-VI in FIG. 15. The bottom 140 is provided with a flat surface 142 in the center of the bottom 140, a grounding portion 141 located on the periphery of the bottom 140, and an inclined portion 144 in which a vertical cross section perpendicular to the bottle axis 11 is inclined downward from an outer peripheral edge 142d of the flat surface 142 toward an inner peripheral edge 141a of the grounding portion 141. The plastic bottle 100 having such a configuration was produced by blow molding a 35g preform. No defective shaping occurred during the blow molding.

[0068] [Comparative Examples 2 to 3] The plastic bottles of Comparative Examples 2 and 3 were shaped as in Example 1, and were evaluated as described below using the ratio D1 / D2 of the diameter D1 of the flat surface 42 in each configuration of the bottom 40 to the maximum diameter D2 of the body 30, the ratios H3 / H1, H4 / H1, H5 / H1 of the heights of the inclined parts 44a, 44b, 44c in the bottle axial direction to the total height of the plastic bottle, and the inclination angles α, β, γ between the extension line of the ground contact part 41 and the tangent to the inclined surface of the maximum curved part of the inclined parts 44a, 44b, 44c as shown in Table 1. In Comparative Examples 2 and 3, the evaluation was performed on plastic bottles with a maximum diameter of the body of the plastic bottle of 75 mm.

[0069] <Method> (Foaming test) The plastic bottles of Examples 1 to 5 and Comparative Examples 1 to 3 were filled with 750 ml of tea-based beverages that easily foam using a rotary filling device 5 shown in Figs. 8 and 12, and liquid and foam portions were generated, and the height of the foam above the liquid surface was measured. The filling valve 8 constituting the rotary filling device 5 is supported vertically by a bracket 9, and the discharge direction of the liquid W from the filling nozzle 2 is also vertically downward (see Fig. 8). In contrast, the support part of the container holder 3 is inclined with respect to the horizontal plane, and the plastic bottle whose flange part 4 of the container is supported by this support part is inclined with respect to the vertical, toward the outer periphery of the wheel 7, downward by an inclination angle θ. This inclination angle θ is generally a value determined by the diameter of the rotation locus of the filling valve 8 of the rotary filling device 5, the production capacity (the number of containers that can be filled with liquid per minute), the number of filling valves 8, and the like, and is known to be about 3 to 6 degrees. As a result, the liquid W discharged vertically downward from the filling nozzle 2 falls substantially along the bottle axis 11 of the plastic bottle 1 due to the centrifugal force generated by the rotation of the wheel 7.

[0070] (Measurement results) A foam height above the liquid surface of 40 mm or more was rated as ×, 20-40 mm as △, 10-20 mm as ◯, and 2-10 mm as ◎. The measurement results (foam height above the liquid surface, evaluation) are shown in Table 1.

[0071] [Table 1]

[0072] As is clear from the evaluation results in Table 1, the foam-preventing bottom of the plastic bottle of each Example had a smaller foam height from the liquid surface during filling than the bottoms of the plastic bottles of Comparative Examples 1 to 3, and it was confirmed that the foam-preventing bottom of the connected part of the bottom and the flat part are excellent in foam prevention. In addition, the bottom of Comparative Example 1 has a slope formed on the bottom, but the foam-preventing effect is not sufficient compared to each Example. The reason for this is that the bottom of Comparative Example 1 does not have multiple downwardly recessed arc-shaped slopes that slope stepwise, so the flow rate of the content liquid flows to the body without being attenuated, causing the liquid to splash up.

[0073] On the other hand, in Comparative Examples 2 and 3, the ratio D1 / D2 of the diameter D1 of the flat surface to the maximum diameter D2 of the body, the ratios H3 / H1, H4 / H1, H5 / H1 of the height in the bottle axial direction of the inclined portions 44a, 44b, 44c to the total height of the plastic bottle, and the inclination angles α, β, γ between the extension line of the ground contact portion and the tangent to the inclined surface of the maximum curved portion of the inclined portions 44a, 44b, 44c are each too small or too large, so that the flow rate attenuation function of the content liquid in the connecting portion is not well expressed and the anti-foaming effect may be insufficient.

[0074] In this way, in order to obtain the above-mentioned good foaming prevention effect even in this embodiment, it is preferable to form flat surface 42 on bottom 40 so that the ratio D1 / D2 of diameter D1 of flat surface 42 to maximum diameter D2 of body portion 30 is 0.05 to 0.30, and to form inclined portions such that the ratios H3 / H1, H4 / H1, H5 / H1 of heights H3, H4, H5 of inclined portions 44a, 44b, 44c in the bottle axis 11 direction to the overall height H1 of plastic bottle 1 are 0.02 to 0.25, and the inclination angles α, β, γ between the extension line of ground contact portion 41 and the tangent to the inclined surface of the maximum curved portion of inclined portions 44a, 44b, 44c are 15 to 60 degrees. [Industrial Applicability]

[0075] The present disclosure is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. The foam-preventing bottom of the plastic bottle of the present disclosure is particularly useful for preventing foaming when a viscous liquid that easily foams, such as vegetable juice or fruit juice, is filled into a plastic bottle supported at an angle using a rotary filling device, but can be applied to plastic bottles used to fill any liquid that foams when filled into a plastic bottle supported at an angle using a rotary filling device. [Explanation of symbols]

[0076] 1 container (plastic bottle) 2 Filling nozzle 3 Container holder 4. Flange of container 5 Rotary filling device 6 Wheel Axle 7 Wheels 8 Filling valve 9 Bracket 10 Mouth 11 Bottle stem 20(20A,20B,20C,20D) Shoulder 21(21a,21b) Shoulder wall 22 Shoulder corner 30 Torso 31(31E,31F) Trunk wall (upper trunk wall, lower trunk wall) 32(32E,32F) Torso corner (upper torso corner, lower torso corner) 33a,33b Step trunk wall 34a, 34b Panel inclination 35 Pressure Absorption Panel 36 Horizontal ribs 37(37a,37b,37c,37d) Chamfered part 38 Circumferential groove 39 Groove 40 bottom 41 Grounding part 41a Inner edge of ground contact area 42 Flat surface 42a Center of flat surface 42b Circle that is the locus of the center of a flat surface 42c Tangent to a circle that is the locus through the center of a flat surface 42d Outer edge of flat surface 42e Inverted dome-shaped recess 43 Continuous section 44a, 44b, 44c Slope part (first slope part, second slope part, third slope part) 45 Plane section 46 (46a, 46b, 46c) Step portion (first step portion, second step portion, third step portion) 48 Reinforcing rib 50 Ridgeline 51 Wall 52 Corner section 53 Vertical ribs 54 Top of vertical rib 55 Groove bottom 100 Plastic bottle (Comparative Example 1) 110 Mouth 120 Shoulder 130 Torso 140 Bottom 141 Grounding part 141a Inner edge of ground contact area 142 Flat surface 142d Outer edge of flat surface 144 Slope S Headspace (remaining air space) a Width of the step wall surface 33a θ Tilt angle θ1, θ2: Angles of panel inclined portions 34a, 34b s1: Depth from the outermost surface of the lower wall to the stepped wall surface 33a s2 Depth from the stepped body wall surface 33a to the stepped body wall surface 33b H1 Total height of plastic bottle H3, H4, H5 Height of the first inclined part, the second inclined part, and the third inclined part in the bottle axial direction c1 Width of the circumferential groove at both ends of the body corner c2 Width of the circumferential groove at the center of the body corner D1 Diameter of flat surface D2 Maximum diameter of the body α, β, γ The inclination angle between the extension line of the ground contact part and the tangent line at the inclination surface of the maximum curve of the first inclined part, the second inclined part, and the third inclined part W Content liquid (liquid)

Claims

1. The bottom is a flat surface at the center of the bottom; a ground portion located on the bottom periphery; A connecting portion that connects an outer peripheral edge of the flat surface to an inner peripheral edge of the ground contact portion; having The connecting portion has a first inclined portion inclined from the flat surface via a first step portion toward the ground portion, a second inclined portion inclined from the first inclined portion via a second step portion toward the ground portion, a plane portion continuing from the second inclined portion and extending toward the ground portion, and a third inclined portion inclined from the plane portion via a third step portion toward the ground portion, the first inclined portion, the second inclined portion, and the third inclined portion are inclined surfaces each having a generally arcuate shape recessed downward, the inclined surface does not bulge downward from a horizontal plane including an outer peripheral edge of the first inclined portion, the second inclined portion, or the third inclined portion, A radial length of the first inclined portion is greater than radial lengths of the second inclined portion and the third inclined portion, a structure in which the radial length of the flat portion is greater than the radial length of the third inclined portion, The height of the first inclined portion in the bottle axial direction is greater than the heights of the second inclined portion and the third inclined portion in the bottle axial direction, a connection portion between the second inclined portion and the flat portion is recessed downward in a V-shape, The flat surface is formed such that a ratio D1 / D2 of a diameter D1 of the flat surface to a maximum diameter D2 of a body portion connected above the bottom portion is 0.05 to 0.

30. Anti-foam bottom for plastic bottles.

2. The flat surface is formed such that a ratio D1 / D2 of a diameter D1 of the flat surface to a maximum diameter D2 of a body portion connected above the bottom portion is 0.10 to 0.

25. The foam-preventing bottom of a plastic bottle according to claim 1.

3. The first inclined portion, the second inclined portion, and the third inclined portion are each a ratio of the first inclined portion, the second inclined portion, or the third inclined portion to the total height of the plastic bottle in the bottle axial direction. The height ratio is 0.02 to 0.

1. The foam-preventing bottom of a plastic bottle according to claim 1 or 2.

4. The inclination angle between the extension line of the ground contact portion and a tangent to the inclined surface of the maximum curved portion of the first inclined portion, the second inclined portion, or the third inclined portion is 20 to 50 degrees. The foam-preventing bottom of a plastic bottle according to any one of claims 1 to 3.

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