WO2011007734A1

WO2011007734A1 - Plastic bottle

Info

Publication number: WO2011007734A1
Application number: PCT/JP2010/061711
Authority: WO
Inventors: 章智関根; 量哉広瀬; 美恵太田; 祐子高田
Original assignee: 大日本印刷株式会社
Priority date: 2009-07-13
Filing date: 2010-07-09
Publication date: 2011-01-20
Also published as: CN102470950B; MY156895A; CN102470950A

Abstract

Disclosed is a plastic bottle (10) that is equipped with a mouth (11), a body (12), and a bottom (20). The bottom (20) is provided with a center (24) and a plurality of feet (21) that are disposed around the periphery of the center (24) and that jut downwards. The strength of each foot (21) is increased as a result of one to six grooves (23), which extend in the radial direction of the bottom (20) and indent inwards, being formed on each foot (21).

Description

Plastic bottle

The present invention relates to a plastic bottle made of a synthetic resin such as polyethylene terephthalate, and more particularly to a plastic bottle with improved pressure resistance and impact resistance. The present invention also relates to a pressure-resistant bottle having high strength when the inside of the bottle is set to a positive pressure.

In recent years, it has been desired to reduce the weight of plastic bottles by reducing the amount of plastic materials used in plastic bottles. However, when the bottle is lightened, the strength of the bottle is weakened. For this reason, the light weight bottle has restrictions such as being limited to designability and over-the-counter sales (hand sale) in order to maintain a certain strength.

Also, when bottles are sold in vending machines, the bottles in the vending machine tend to be laid sideways and loaded, so that the bottles in the lower tier tend to be crushed. There is a tendency that the bottle cannot be discharged or the bottle is recessed during storage or discharge in the vending machine. In order to solve this, there is a technique of filling a bottle with liquid nitrogen or the like immediately after the bottle is filled with the content liquid in the process of manufacturing the bottle beverage, thereby positively increasing the bottle internal pressure and closing the bottle. Thereby, the inside of a bottle becomes a positive pressure and it is possible to raise the intensity | strength of a bottle. In addition, filling the inside of the bottle with an inert gas such as nitrogen as described above also has an effect of preventing the content liquid (for example, green tea) from being oxidized.

Also, when the bottle is filled with natural foaming water (sparkling water) or oxygen water, the inside of the bottle becomes slightly positive. Alternatively, if the bottle is filled with content liquid such as green tea or coffee and the filling temperature is lower than the selling temperature, the volume of the inner solution expands by increasing the temperature difference between the selling and filling, and the inside of the bottle expands. Positive pressure.

As described above, when the bottle has a positive pressure, when a bottle having a bottom portion having a general shape is used, the bottom portion swells due to the positive pressure in the bottle, and the total height of the bottle increases. Or the unevenness | corrugation of a bottom part will invert (buckling), and a bottle will become independent.

Utility Model Registration No. 2551699 Japanese Patent Laid-Open No. 10-139029 Japanese Patent Publication No. 3-39897

The present invention has been made in consideration of such points, and an object of the present invention is to provide a plastic bottle having high pressure resistance and impact resistance even when it is thinned for weight reduction. To do. Another object of the present invention is to provide a pressure-resistant bottle that can reduce deformation when the inside of the bottle is set to a positive pressure and that is not easily deformed by an external force.

The present invention is a plastic bottle, comprising a mouth, a trunk, and a bottom, the bottom having a central portion and a plurality of legs that are disposed around the central portion and project downward. The plastic bottle is characterized in that each leg portion is formed with one to six grooves extending along the radial direction of the bottom portion and retracting inward.

According to the present invention, each leg has a grounding surface, a leg inner side surface provided on the inner side of the grounding surface, and a leg outer side surface provided on the outer side of the grounding unit, and each groove extends from the inner side surface of the leg part. It is a plastic bottle characterized in that it extends to the outer surface of the leg portion through the ground contact surface.

The present invention is a plastic bottle characterized in that the bottom has 5 to 9 legs.

The present invention is the plastic bottle characterized in that each leg has a grounding surface, and the thickness of the grounding surface is 0.04 mm to 0.3 mm.

The present invention is a plastic bottle characterized in that each groove has a depth of 0.05 mm to 3 mm.

The present invention is a plastic bottle characterized in that each groove has a length of 3 mm to 25 mm.

The present invention is a plastic bottle characterized in that the width of each groove is 0.2 mm to 5 mm.

In the present invention, in each leg, the ratio of the total area (S _g ) of the bottom surface of each groove to the total area (S _T ) of the ground contact surface, the inner surface of the leg, and the outer surface of the leg is 2% or more and 50 It is a plastic bottle characterized by being less than%.

The present invention is a plastic bottle characterized by having a structure in which a barrier layer having gas barrier properties and light shielding properties is laminated or a structure in which a resin having gas barrier properties and light shielding properties is blended.

The pressure-resistant bottle includes a mouth portion, a trunk portion, and a bottom portion. The bottom portion extends from the central portion to the peripheral portion and protrudes downward, and includes a plurality of legs each including a grounding surface. And a flat surface extending downward from the central portion toward the peripheral portion is formed between the leg portions, and the ground contact surface of each leg portion is formed in a curved shape in a cross section from the central portion to the peripheral portion, and at least 1 The pressure-resistant bottle is characterized in that a groove is formed in one leg portion from the central portion side to the peripheral portion side through the grounding surface.

The present invention is a pressure-resistant bottle characterized in that the number of grooves formed in each leg is 1 to 6.

The present invention is the pressure resistant bottle characterized in that each groove has a depth of 0.05 mm to 3 mm.

The present invention is a pressure-resistant bottle characterized in that at least two grooves are formed in each leg, and the distance between the grooves is equal to or greater than the width of each groove.

In the present invention, the length of each groove is 1 mm when the length from the lowest point of the ground plane toward the peripheral side is L ₁ and the length from the lowest point of the ground plane toward the center side is L _2. ≦ L ₁ ≦ 10 mm and 0.5 mm ≦ L ₂ ≦ 7 mm.

The present invention is a pressure-resistant bottle characterized in that a reinforcing groove extending from the central side to the peripheral side and retracting upward is formed on each flat surface.

The present invention is a pressure-resistant bottle characterized in that a recess that is retracted upward is formed in the center of the bottom.

The present invention is a pressure-resistant bottle characterized in that a recess that is retracted upward is formed in the center of the bottom, and the bottom surface of the recess and the bottom surface of the reinforcing groove are flush with each other.

The present invention is the pressure-resistant bottle, wherein each flat surface constitutes a part of a concave curved surface that curves upward in a cross section from the central portion toward the peripheral portion.

The present invention is a pressure-resistant bottle characterized in that a protruding height from a flat surface on the ground contact surface of each leg is 1 mm to 3 mm.

The present invention is a pressure-resistant bottle characterized by having a structure in which a barrier layer having a gas barrier property and a light shielding property is laminated or a structure in which a resin having a gas barrier property and a light shielding property is blended.

The pressure-resistant bottle includes a mouth portion, a body portion, and a bottom portion. The bottom portion extends from the central portion to the peripheral portion and protrudes downward, and has a plurality of legs each including a grounding surface. A flat surface extending upward from the central portion toward the peripheral portion is formed between the respective leg portions, and the peripheral portion of each leg portion is retracted inward in the radial direction from the trunk portion, together with the peripheral portion of each flat surface. The pressure-resistant bottle is characterized in that a groove is formed in at least one leg portion from the central portion side to the peripheral portion side through the grounding surface.

In the present invention, the length of each groove is 1 mm when the length from the lowest point on the ground plane toward the peripheral side is L ₃ and the length from the lowest point on the ground plane toward the center is L _4. ≦ L ₃ ≦ 10 mm and 0.5 mm ≦ L ₄ ≦ 7 mm.

The present invention is the pressure-resistant bottle characterized in that each flat surface constitutes a part of a dome-shaped curved surface that curves downward in a cross section from the central portion toward the peripheral portion.

The present invention is a pressure-resistant bottle characterized in that the bottom portion has an odd number of legs.

The present invention is a pressure-resistant bottle characterized in that the protruding height of each leg is 10% to 20% of the diameter of the trunk.

According to the present invention, the pressure resistance and impact resistance of the plastic bottle can be enhanced even when the plastic bottle is thin in order to reduce the weight.

Further, according to the present invention, it is possible to reduce deformation when the inside of the pressure-resistant bottle is made positive pressure. Further, even when the pressure-resistant bottle is thin, the strength of the bottom can be increased, so that deformation such as a dent hardly occurs even when an external force is applied to the bottom of the bottle.

FIG. 1 is a front view showing a plastic bottle according to a first embodiment of the present invention. FIG. 2 is a vertical sectional view showing the bottom of the plastic bottle according to the first embodiment of the present invention. FIG. 3 is a perspective view showing the bottom of the plastic bottle according to the first embodiment of the present invention. FIG. 4 is a perspective view showing the bottom of a plastic bottle according to Comparative Example 1 and Comparative Example 2 of the first embodiment of the present invention. FIG. 5 is a graph comparing the total elongation of plastic bottles when the internal pressure of the bottle is increased. FIG. 6 is a graph comparing the gate depth elongation rate of a plastic bottle when the internal pressure of the bottle is increased. FIG. 7 is a front view showing a pressure-resistant bottle according to the second embodiment of the present invention. FIG. 8 is a perspective view showing the bottom of a pressure-resistant bottle according to the second embodiment of the present invention. FIG. 9 is a bottom view showing the bottom part of the pressure-resistant bottle according to the second embodiment of the present invention (viewed in the direction of arrow IX in FIG. 7). FIG. 10 is a vertical cross-sectional view (cross-sectional view taken along the line XX of FIG. 9) showing the bottom of the pressure-resistant bottle according to the second embodiment of the present invention. FIG. 11 is a partial cross-sectional view (cross-sectional view taken along the line XI-XI in FIG. 9) showing the leg portion of the pressure-resistant bottle according to the second embodiment of the present invention. FIG. 12 is an enlarged side view showing the legs of the pressure-resistant bottle according to the second embodiment of the present invention (viewed in the direction of the arrow XII in FIG. 9). FIG. 13 is a schematic cross-sectional view showing a change in bottom shape when an internal pressure is applied to a bottle as a comparative example. FIG. 14 is a perspective view showing the bottom of a pressure-resistant bottle according to a modification of the second embodiment of the present invention (a diagram corresponding to FIG. 8). FIG. 15 is a front view showing a pressure-resistant bottle according to the third embodiment of the present invention. FIG. 16 is a perspective view showing the bottom of a pressure-resistant bottle according to the third embodiment of the present invention. FIG. 17 is a bottom view showing the bottom of the pressure-resistant bottle according to the third embodiment of the present invention (viewed in the direction of the arrow XVII in FIG. 15). FIG. 18 is a vertical sectional view (cross-sectional view taken along the line XVIII-XVIII in FIG. 17) showing the bottom of the pressure-resistant bottle according to the third embodiment of the present invention. FIG. 19 is a partial cross-sectional view (cross-sectional view taken along the line XIX-XIX in FIG. 17) showing the leg portion of the pressure-resistant bottle according to the third embodiment of the present invention. FIG. 20 is an enlarged side view (viewed in the direction of the arrow XX in FIG. 17) showing the leg portion of the pressure-resistant bottle according to the third embodiment of the present invention. FIG. 21 is a perspective view showing the bottom of a pressure-resistant bottle according to a modification of the third embodiment of the present invention (a diagram corresponding to FIG. 16).

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3 are views showing a first embodiment of the present invention.

First, the outline of the plastic bottle according to the present embodiment will be described with reference to FIGS. In the following, “upper” and “lower” refer to the upper and lower sides of the plastic bottle 10 in an upright state (FIG. 1), respectively.

As shown in FIG. 1, a plastic bottle 10 made of a petaloid bottle includes a mouth part 11, a body part 12 provided below the mouth part 11, and a bottom part 20 provided below the body part 12. .

This plastic bottle 10 is a preform produced by injection molding a synthetic resin material and biaxially stretch blow molded. In addition, it is preferable to use a thermoplastic resin, especially PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate) as a material of the preform, that is, the plastic bottle 10.

Further, the plastic bottle 10 can be formed as a multilayer molded bottle having two or more layers. That is, by extrusion molding or injection molding, for example, the intermediate layer has gas barrier properties and light shielding properties such as MXD6, MXD6 + cobalt salt, PGA (polyglycolic acid), EVOH (ethylene vinyl alcohol copolymer) or PEN (polyethylene naphthalate). A multilayer bottle having gas barrier properties and light shielding properties may be formed by extrusion molding a preform composed of three or more layers as the resin (intermediate layer), and then blow molding. Such an intermediate layer is preferably provided in at least the body 12 of the plastic bottle 10. Moreover, it is preferable to provide an intermediate layer in the bottom portion 20 except for the central portion 24 (described later). This is because this portion may cause delamination (delamination) when subjected to an impact such as a case dropping. In order to have gas barrier properties and light shielding properties, a blend bottle in which thermoplastic resins are blended may be formed as well as multilayers.

Furthermore, by depositing inorganic oxides such as silica and alumina and amorphous carbon on the inner wall of the bottle container, the gas barrier property can be improved while maintaining transparency. When coating means are used, gas barrier properties are improved by coating a thermosetting cross-linked coating film of EVOH with an aromatic polyhydric epoxy compound obtained by reacting metaxylenediamine and epichlorohydrin, or EVOH. Can be made. When EVOH is coated, gas barrier properties are reduced due to moisture absorption. Therefore, it is preferable to coat a moisture-proof resin such as a polyolefin resin thereon. Any one kind of such gas barrier property improving means may be used, but the gas barrier property can be further improved by combining two or more means.

By the way, as shown in FIGS. 1 to 3, the bottom portion 20 of the plastic bottle 10 is provided with a substantially circular center portion 24 as viewed from the bottom surface direction, and is provided around the center portion 24 and arranged at equal intervals in the circumferential direction. And a plurality (five in FIG. 1 to FIG. 3) of leg portions 21 projecting downward.

The number of the leg portions 21 can be 5 to 9. However, the number of the leg portions 21 is most preferably 5 to 7 from the viewpoint of stably erecting the plastic bottle 10 and improving the moldability of the light weight bottle.

2 and 3, each leg 21 includes a grounding surface 21a, a leg inner side surface 21b extending upward from the grounding surface 21a toward the central portion 24, and a peripheral edge of the bottom 20 from the grounding surface 21a. A leg outer surface 21c extending upward toward the portion 20b. Among these, the leg inner side surface 21b has a substantially triangular shape when viewed from the bottom surface direction (see FIG. 3). The leg outer surface 21 c is connected to the lower end of the trunk 12 and is flush with the trunk 12.

On the other hand, between each leg part 21, the curved surface 22 extended upwards toward the peripheral part 20b of the bottom part 20 from the center part 24 is formed. As shown in FIG. 2, each curved surface 22 constitutes a part of a substantially spherical curved surface that curves downward.

Each leg portion 21 is formed with an elongated groove 23 extending from the center portion 24 side to the peripheral edge portion 20b side along the radial direction of the bottom portion 20 and drawn into the plastic bottle 10 inward (substantially upward). Yes.

As shown in FIGS. 1 and 3, three grooves 23 are formed in each leg 21. These three grooves 23 are composed of a groove 23a located at the center of the leg portion 21 and a pair of

grooves

23b, 23b located on both sides of the groove 23a (see FIG. Groove 23).

In addition, the number of the grooves 23 formed in each leg portion 21 is not limited to three, and may be one to six. When the number of the grooves 23 is 7 or more, as will be described later, when the plastic bottle 10 is produced by blow molding, there arises a problem with the shaping failure of the bottom portion 20.

Each groove 23 extends from the leg inner side surface 21b to the leg outer side surface 21c through the ground contact surface 21a. Thereby, the intensity | strength of the leg part 21 whole containing the grounding surface 21a is raised. The length of each groove 23 is preferably 3 mm to 25 mm, and the width of each groove 23 is preferably 0.2 mm to 5 mm.

Furthermore, the depth of each groove 23 is preferably 0.05 mm to 3 mm, and more preferably 0.8 mm to 1.2 mm. In addition, when the depth of each groove | channel 23 shall be less than 0.05 mm, the effect of this Embodiment of raising the intensity | strength of each leg part 21 is hard to be acquired. On the other hand, when the depth of each groove 23 exceeds 3.0 mm, there is a risk of forming defects when the plastic bottle 10 is blow-molded.

In each leg portion 21, the total area (S _g ) of the bottom surface 23 c (see FIG. 2) of each groove 23 with respect to the total area (S _T ) of the ground contact surface 21 a, the leg inner side surface 21 b, and the leg outer side surface 21 c. The ratio is preferably 2% or more and 50% or less (that is, 0.02 ≦ (S _g / S _T ) ≦ 0.5). When the ratio is less than 2%, it is difficult to obtain the effect of the present embodiment that increases the strength of each leg 21. On the other hand, when the ratio is more than 50%, there is a risk of forming failure when the plastic bottle 10 is blow-molded.

The size of the plastic bottle 10 is not limited and may be made of any size bottle.

In the present embodiment, as described above, the three grooves 23 are formed in each leg portion 21, and the strength of each leg portion 21 is increased. As a result, even if the plastic bottle 10 is a thin-walled bottle, it is strongly resistant to deformation and hardly deformed. Specifically, the thickness of each leg portion 21 on the ground contact surface 21a can be set to 0.04 mm to 0.3 mm, particularly 0.05 mm to 0.25 mm.

The object to be filled in the plastic bottle 10 is not limited, but the bottle internal pressure is made positive by using carbonated drinking water, natural foaming water (sparkling water), oxygen water, liquid nitrogen, etc. in which the inside of the plastic bottle 10 becomes positive after filling. Soft drinks are suitable. Here, the positive pressure inside the plastic bottle 10 means that the internal pressure of the plastic bottle 10 becomes 1 kPa to 400 kPa when the liquid temperature of the filled content liquid is 20 ° C. In particular, when the internal pressure of the plastic bottle 10 is 1 kPa to 150 kPa, the effect of the present embodiment is easily obtained.

Next, the operation of the present embodiment having such a configuration will be described.

First, the plastic bottle 10 is filled with a liquid content such as carbonated drinking water, natural foaming water (sparkling water), oxygen water, green tea, or coffee, and then liquid nitrogen is filled into the head space and then closed. . At this time, the inside of the plastic bottle 10 becomes a positive pressure (for example, when the liquid temperature of the content liquid is 20 ° C., the internal pressure immediately after filling is 1 kPa to 400 kPa) due to the filled inert gas or the content liquid.

When the inside of the plastic bottle 10 becomes a positive pressure, a force acts from the inside of the plastic bottle 10 to the outside, and pressure is applied to the bottom 20 from the upper side to the lower side. In this state, the plastic bottle 10 (hereinafter also referred to as a beverage product) filled with the contents is shipped, transported to a retail store or put into a vending machine and sold to a consumer.

In the present embodiment, each leg 21 is formed with three grooves 23 extending along the radial direction of the bottom 20 and retracting inward. Therefore, even if the pressure in the plastic bottle 10 becomes positive and a substantially downward force is applied to the bottom portion 20, the strength of each leg portion 21 is increased, and the overall height of the plastic bottle 10 does not change greatly. This prevents troubles such as the plastic bottle 10 not entering the rack of the vending machine or the cardboard case.

In addition, since the strength of each leg portion 21 is increased, even when an impact is applied to the bottom portion 20 in a state where the inside of the plastic bottle 10 is at a positive pressure, the leg portion 21 is deformed such as a dent. Is unlikely to occur. Thereby, it is possible to prevent the commercial value of the plastic bottle 10 filled with the contents from being damaged, and to prevent the collapse of goods during transportation and the clogging in the vending machine.

In particular, such an effect is more prominent when the plastic bottle 10 is formed thin (that is, when the thickness of the ground contact surface 21a is 0.04 mm to 0.3 mm as described above).

As described above, according to the present embodiment, each leg portion 21 is formed with one to six grooves 23 extending along the radial direction of the bottom portion 20 and retracting inward, so that the weight can be reduced. Even when the plastic bottle 10 is thin, the pressure resistance and impact resistance of the plastic bottle 10 can be improved.

Further, according to the present embodiment, each groove 23 extends from the leg inner side surface 21b to the leg outer side surface 21c through the ground contact surface 21a, so that the strength of the entire leg portion 21 is enhanced.

Next, specific examples in the present embodiment will be described with reference to FIGS.

Example 1
First, as shown in FIG. 1, a plastic bottle 10 (Example 1) for 500 ml in which three grooves were formed in the leg portion 21 of the bottom portion 20 was produced. In this case, the plastic bottle 10 (Example 1) was produced by carrying out biaxial stretch blow molding of 18g preform. This plastic bottle 10 (Example 1) is made thinner than a plastic bottle generally used conventionally.

(Comparative Example 1)
A 500 ml plastic bottle 50 (Comparative Example 1) shown in FIG. 4 having the same thickness as that of Example 1 except that no groove is formed in the leg portion 52 of the bottom 51. Was made.

(Comparative Example 2)
A 500 ml plastic bottle 70 (Comparative Example 2) shown in FIG. 4 was produced in the same manner as in Comparative Example 1 except that it was formed thick. In this case, a plastic bottle 70 (Comparative Example 2) was produced by biaxially stretching blow molding a 28 g preform. The plastic bottle 70 (Comparative Example 2) has a thickness 1.5 to 4 times that of the plastic bottle 10 of Example 1.

Next, an inert gas was injected into these three types of

plastic bottles

10, 50, and 70, and each was sealed with a positive pressure (50 kPa).

(Case drop test)
Next, each of the three types of

plastic bottles

10, 50, and 70 was housed in a case of 24, and the cases were collectively dropped (case dropped) from a height of 50 cm. Subsequently, for each of the

plastic bottles

10, 50, and 70, the number of the recessed bottles and the area of the recessed portions among the 24 bottles were quantified and compared (Table 1).

As a result, as for the plastic bottle 10 of Example 1, there was no bottle in which the dent occurred. Thus, by forming three grooves in the leg portion 21, the number of dents and the area of the dents were greatly improved as compared with the

plastic bottles

50 and 70 of Comparative Examples 1 and 2.

(Verification by vending machine)
Next, 12 of each of the three types of

plastic bottles

10, 50 and 70 were put into the vending machine, and the discharge suitability from the vending machine and the presence or absence of dents in the bottle were verified (Table 2).

As a result, with regard to the plastic bottle 10 of Example 1, there was no bottle with poor carry-out suitability, and there was no bottle with dents. As described above, by forming the three grooves in the leg portion 21, the carry-out suitability and the recessed area are greatly improved as compared with the plastic bottle 50 of Comparative Example 1. In addition, as for the plastic bottle 70 (Comparative Example 2) generally used in the past, there were no bottles with poor carry-out suitability and bottles with dents.

(Measurement of total elongation and gate depth elongation)
Next, when the internal pressures of the three types of

plastic bottles

10, 50, and 70 were increased from 0 kPa to 110 kPa, the total high elongation rate and the bottom gate depth elongation rate of each plastic bottle were measured. Here, the total height elongation refers to a value obtained by dividing the change amount of the total height of the plastic bottle based on the total height of the plastic bottle when the internal pressure is 0 kPa by the total height of the plastic bottle when the internal pressure is 0 kPa. The gate depth elongation is the value obtained by dividing the amount of change based on the gate depth of a plastic bottle whose internal pressure is 0 kPa by the gate depth of the plastic bottle when the internal pressure is 0 kPa. A large value indicates that the plastic bottle has a large dimensional change. The gate depth means the distance in the height direction between the center of the bottom of each bottle (for example, the center 24 in the first embodiment) and the bottle grounding surface. The results are shown in FIGS.

As a result, the total height of the plastic bottle 10 according to Example 1 increased as the internal pressure increased (FIG. 5), and the gate depth of the bottom 20 decreased (FIG. 6). However, although the plastic bottle 10 according to Example 1 is thinner than the plastic bottle 70 (Comparative Example 2), the total high elongation rate and the gate depth elongation rate are the plastic bottle 70 (Comparative Example 2). ) And higher than that (FIGS. 5 and 6).

On the other hand, as for the plastic bottle 50 of Comparative Example 1, compared with the plastic bottle 10, the total high elongation rate and the gate depth elongation rate were large.

(Number of grooves and blow moldability)
(Comparative Example 3)
500 ml plastic bottle having the same wall thickness as in Example 1 except that seven grooves are formed in each leg so that S _g / S _t ≧ 50%. (Comparative Example 3) was produced. In this case, a plastic bottle (Comparative Example 3) was produced by biaxially stretching blow molding an 18 g preform.

As a result, regarding the plastic bottle of Comparative Example 3, a shaping failure occurred during blow molding. This is considered to cause shaping defects when the number of grooves is 7 or more.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. 7 to 14 are views showing a second embodiment of the present invention.

First, an outline of a pressure-resistant bottle according to the present embodiment will be described with reference to FIGS. In the following, the term “flat surface” is used to mean a smooth surface having no irregularities on the surface. However, even if it has fine irregularities such as wrinkles, it is regarded as a “flat surface”. In the following, “upper” and “lower” refer to the upper and lower sides in a state where the pressure-resistant bottle 110 is upright (FIG. 7).

As shown in FIG. 7, the pressure-resistant bottle 110 includes a mouth portion 111, a body portion 112 provided below the mouth portion 111, and a bottom portion 120 provided below the body portion 112.

The pressure-resistant bottle 110 is a biaxial stretch blow-molded preform made by injection molding polyethylene terephthalate (hereinafter abbreviated as PET). As a material for the preform, that is, the pressure-resistant bottle 110, polypropylene (PP), polylactic acid (PLA), or other various thermoplastic resins can be used in addition to PET.

Also, the preform may have a multilayer structure, and at least one of them may be a gas barrier layer. As the gas barrier layer, a structure in which a gas barrier resin layer such as saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH) or MXD6 (polymetaxylylene adipamide) is laminated can be employed. In the case of blend molding of two or more synthetic resins, the gas barrier property can be improved by, for example, blending a gas barrier resin such as MXD6 with PET and injection molding the preform. Also, oxygen barrier properties can be improved by blending an oxygen absorbent in addition to the synthetic resin into PET.

7 to 12, the bottom 120 has nine (plural) leg portions 121 that extend from the central portion 120a to the peripheral portion 120b and project downward.

It is preferable to provide three or more leg portions 121 in order to stably erect the pressure-resistant bottle 110, but the upper limit is about 15 from the viewpoint of formability. In order to effectively prevent buckling, the number of leg portions 121 is preferably an odd number.

As shown in FIGS. 8 and 9, the nine leg portions 121 are arranged at equal intervals along the peripheral edge portion 120 b of the bottom portion 120.

Further, as shown in FIGS. 9 and 10, each leg 121 includes a grounding surface 121a, an inner inclined surface 121b extending upward from the grounding surface 121a toward the central portion 120a, and a peripheral portion 120b side from the grounding surface 121a. And an outer inclined surface 121c extending upward. Among these, the ground contact surface 121a is formed in a curved surface in a cross section from the central portion 120a to the peripheral edge portion 120b (see the vertical sectional view of FIG. 10). The inner inclined surface 121b has a substantially triangular shape when viewed from the bottom surface direction (see FIG. 9).

On the other hand, a flat surface 122 extending downward from the central portion 120a toward the peripheral edge portion 120b is formed between the leg portions 121. Each flat surface 122 constitutes a part of a concave curved surface that curves upward in a cross section from the central portion 120a toward the peripheral edge portion 120b (see FIG. 10).

Furthermore, a groove 151 is formed in each leg 121 from the central portion 120a side (inner inclined surface 121b) through the ground contact surface 121a toward the peripheral edge 120b side (outer inclined surface 121c). In the present embodiment, two grooves 151 are formed in every leg 121, but the present invention is not limited to this, and the grooves 151 may be provided only in specific (one or more) legs 121.

Although the number of the grooves 151 is not limited, it is preferable that the number of the grooves 151 be one to six for each leg 121. However, if the number of the grooves 151 formed in each leg 121 is one, the effect of the present embodiment to be described later is reduced, and if the number is five or more, the moldability of the legs 121 may be slightly deteriorated. . For this reason, it is more desirable that the number of grooves 151 formed in each leg 121 is two to four.

Further, on each flat surface 122, an elongated reinforcing groove 123 extending from the center portion 120a side to the peripheral edge portion 120b side and retracting upward is formed. That is, the bottom portion 120 has nine reinforcing grooves 123 that are radially spaced from the central portion 120a.

Further, a recess 124 having a circular shape as viewed from the bottom surface is formed in the center of each flat surface 122 while being retracted upward. The concave portion 124 is formed continuously with the reinforcing groove 123, and the bottom surface 124a of the concave portion 124 and the bottom surface 123a of the reinforcing groove 123 are flush with each other (see FIG. 10).

Furthermore, a bottom inner side surface 125 is formed in a planar region surrounded by each leg 121, the reinforcing groove 123, and the recess 124. The bottom inner side surface 125 is formed continuously with the flat surface 122 and is flush with the flat surface 122.

The size of the pressure-resistant bottle 110 is not limited, and may be made of any size bottle. 10 For example, when the capacity of the pressure-resistant bottle 110 is 500 ml, the diameter phi ₁ of the body portion 112 and 60mm or 70 mm, the protrusion height h ₁ from the planar surface 122 of the ground plane 121a of each leg 121 1 mm to 3 mm is preferable. Further, the bottom depth of the bottom 120 (that is, the distance between the ground contact surface 121a of each leg 121 and the bottom surface 124a of the recess 124) h ₂ is preferably 7 mm to 22 mm.

Note for example when the capacity of the pressure-resistant bottle 110 is less than 350ml, if the diameter phi ₁ is 50mm to 68mm of the barrel 112, in the case of 1000ml is the diameter phi ₁ of the body 112 70 mm to 90 mm, of 1500ml barrel The diameter φ _{1 of} 112 is 80 mm to 100 mm, the protruding height h ₁ of the ground contact surface 121a of each leg 121 from the flat surface 122 is 1 mm to 3 mm, and the bottom depth h ₂ of the bottom 120 is 7 mm to 22 mm. It is preferable.

Further, in the cross section from the central portion 120a to the peripheral portion 120b, it is preferable that the radius of curvature R of the ground contact surface 121a of each leg 121 is 3 mm to 8 mm. Furthermore, it is preferable that the thickness t ₁ of the body portion 112 is 0.1 mm to 0.5 mm.

In FIG. 11, the depth d of each groove 151 is preferably 0.05 mm to 3 mm, and more preferably 0.8 mm to 1.2 mm. When the depth d of the groove 151 is too shallow, the effect of providing the groove 151 is diminished, and when the depth d of the groove 151 is too deep, the moldability of the leg 121 may be slightly deteriorated.

Also, in FIG. 11, the length of each groove 151 is L ₁ from the lowest point 121d of the ground contact surface 121a toward the peripheral edge 120b side (outer inclined surface 121c side), and the lowest point 121d of the ground contact surface 121a. If the length toward the central portion 120a side (inner inclined surface 121b side) was L ₂ from, it is preferable to 1mm ≦ L ₁ ≦ 10mm and 0.5 mm ≦ L ₂ ≦ 7 mm. If the length of the groove 151 is too short, the effect of providing the groove 151 is reduced. On the other hand, if the length of the groove 151 is too long, the moldability of the leg 121 may be slightly deteriorated.

In FIG. 12, the width b of each groove 151 is preferably 0.2 mm to 5 mm. Further, when two or more grooves 151 are formed in each leg 121 as in the present embodiment, it is desirable that the distance a between the grooves 151 be equal to or larger than the width b of each groove 151 (b ≦ a). This is because, if the distance a between the grooves 151 is smaller than the width b of the grooves 151 (b> a), the moldability may be deteriorated, and the area of the ground contact surface 121a is reduced. This is because the self-supporting property of the bottle 110 may be adversely affected.

First, the pressure bottle 110 is filled with a content liquid such as green tea, and then an inert gas such as nitrogen is filled in the head space and then closed. At this time, the inside of the pressure-resistant bottle 110 becomes a positive pressure (for example, 20 to 40 kPa) by the filled inert gas or content liquid.

When the inside of the pressure-resistant bottle 110 becomes a positive pressure, a force from the inside to the outside of the pressure-resistant bottle 110 acts, and pressure is applied from the upper side to the lower side at the bottom 120.

On the other hand, in the present embodiment, the bottom portion 120 has nine leg portions 121 extending from the central portion 120a to the peripheral edge portion 120b and projecting downward, and between the respective leg portions 121, the central portion 120a to the peripheral edge portion A flat surface 122 extending downward toward 120b is formed. Each flat surface 122 constitutes a part of a concave curved surface that curves upward in a cross section from the central portion 120a toward the peripheral edge portion 120b. Therefore, even if the pressure bottle 110 has a positive pressure and a downward force is applied to the bottom 120, the bottom 120 is not easily deformed because the stress does not concentrate on the bottom 120. Furthermore, since the adjacent leg portions 121 and the flat surface 122 positioned between the leg portions 121 form a rib structure, this also acts to prevent the bottom portion 120 from being deformed. The reinforcing groove 123 and the recess 124 of the bottom 120 also serve to prevent the deformation of the bottom 120 by the same action.

Further, the ground contact surface 121a, which is a surface to which the pressure resistant bottle 110 is grounded, is formed in a curved surface in a cross section from the central portion 120a to the peripheral portion 120b. Thus, even when the pressure in the pressure-resistant bottle 110 is increased and the flat surface 122 and the bottom inner side surface 125 are deformed downward, the total height change amount of the pressure-resistant bottle 110 is suppressed to be small.

Further, when the inside of the pressure-resistant bottle 110 becomes positive pressure, a force is exerted to cause the curvature radius R of the ground contact surface 121a of the leg 121 to increase, but the groove 151 provided in the leg 121 causes the force to be deformed. The deformation of the radius of curvature R can be suppressed. As a result, the total height change amount of the pressure bottle 110 can be further reduced. Moreover, not only can the change in the overall height of the pressure-resistant bottle 110 be suppressed, but it can also be prevented that the legs 121 are deformed and wrinkled due to positive pressure.

That is, as shown in FIG. 13 as a comparative example, if the ground contact surface 131 at the bottom of the bottle is a flat horizontal surface, when the pressure inside the bottle increases and the bottom of the bottle deforms, the outer edge of the ground contact 131 The angle α _{1 of the} part 131a and the angle α ₂ of the inner edge part 131b of the ground surface 131 are each deformed in a direction of increasing (imaginary line (two-dot chain line) in FIG. 13). For this reason, the ground contact surface 131 is deformed so that the inner edge portion 131b is directed downward, so that the total height change amount of the bottle is increased.

On the other hand, in the present embodiment, as described above, the ground contact surface 121a is formed in a curved shape in a cross section from the central portion 120a to the peripheral portion 120b, and is formed on the leg portion 121 from the central portion 120a side. Since the groove 151 is formed through the ground contact surface 121a toward the peripheral edge 120b, when the pressure inside the pressure resistant bottle 110 increases, the radius of curvature R of the ground contact surface 121a of each leg 121 hardly increases. Thereby, the total height change amount of the pressure-resistant bottle 110 can be suppressed small.

As described above, according to the present embodiment, the bottom portion 120 has the plurality of leg portions 121 extending from the central portion 120 a to the peripheral edge portion 120 b and protruding downward, and between the respective leg portions 121, the central portion 120 a extends to the peripheral edge portion. A flat surface 122 extending downward toward 120b is formed. Each flat surface 122 constitutes a part of a concave curved surface that curves upward in a cross section from the central portion 120a toward the peripheral edge portion 120b. Accordingly, the strength of the bottom 120 is increased, and deformation (buckling or the like) of the bottom 120 can be prevented when the pressure bottle 110 is positively pressurized.

Further, according to the present embodiment, the reinforcing groove 123 extending from the central portion 120 a to the peripheral edge portion 120 b and retracting upward is formed on each flat surface 122, and the concave portion 124 retracting upward is formed in the central portion 120 a of the bottom portion 120. ing. As a result, the strength of the bottom 120 is increased, and the deformation of the bottom 120 can be further suppressed.

Further, according to the present embodiment, the ground contact surface 121a of each leg 121 is formed in a curved shape in a cross section from the central part 120a to the peripheral part 120b, and is in contact with the leg 121 from the central part 120a side. Since the groove 151 is formed through the ground 121a toward the peripheral edge 120b, the total height change amount of the pressure bottle 110 can be reduced when the pressure bottle 110 has a positive pressure.

Furthermore, the groove 151 provided in each leg 121 can prevent the leg 121 from being deformed and generating wrinkles when the inside of the bottle is made positive. Further, the leg 121 may have a dent or the like due to vibration when transporting the pressure-resistant bottle 110 filled with the content liquid, dropping the pressure-resistant bottle 110 by mistake, or dropping impact when selling with a vending machine. Although deformation may occur, since the leg portion 121 is reinforced by the groove 151, such deformation can be prevented. Even if the leg 121 is deformed, there is an effect that the deformation is not conspicuous because of the groove 151.

Further, according to the present embodiment, since the leg portion 121 of the bottom 120 is not noticeable when viewed from the outside of the pressure bottle 110, the appearance shape of the pressure bottle 110 is close to the appearance shape of a general bottle, and the consumer There is no possibility of misunderstanding the contents of the pressure bottle 110. That is, since a plastic bottle having a petaloid-shaped bottom is generally excellent in pressure resistance, many of them are used for filling and selling carbonated beverages. For this reason, consumers have a strong image that a plastic bottle having a petaloid-shaped bottom is filled with a carbonated beverage. According to the present embodiment, since the appearance shape of the pressure-resistant bottle 110 is close to the appearance shape of a general bottle, it is possible to prevent the consumer from misinterpreting the contents.

In addition, since the appearance shape of the pressure-resistant bottle 110 is close to the appearance shape of a general bottle, the inside of the pressure-resistant bottle 110 can be used as a non-positive pressure. For example, in some cases, green tea is filled and then nitrogen is filled to make the pressure bottle 110 positive pressure to make a product for a vending machine. In other cases, the same pressure bottle 110 is filled with only green tea and is not automatic. It is also possible to make a product for a vending machine. Therefore, it is not necessary to prepare two types of bottle molds, and therefore there is no need to replace the molds in the bottle production factory, so that there is a secondary effect that the mold investment cost and the replacement time can be saved.

(Modification)
In addition, when the intensity | strength requested | required with respect to the pressure | voltage resistant bottle 110 is low, it is not necessary to provide the reinforcement groove | channel 123 in the bottom part 120 like the modification shown in FIG. Further, although not shown, the reinforcing groove 123 may be provided in the bottom 120 and the recess 124 may not be provided. Alternatively, neither the reinforcing groove 123 nor the recess 124 may be provided on the bottom 120.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. 15 to 21 are views showing a third embodiment of the present invention.

First, an outline of a pressure-resistant bottle according to the present embodiment will be described with reference to FIGS. In the following, the term “flat surface” is used to mean a smooth surface having no irregularities on the surface. However, even if it has fine irregularities such as wrinkles, it is regarded as a “flat surface”. In the following, “upper” and “lower” refer to the upper and lower sides in a state where the pressure-resistant bottle 210 is erected (FIG. 15), respectively.

As shown in FIG. 15, the pressure-resistant bottle 210 includes a mouth portion 211, a body portion 212 provided below the mouth portion 211, and a bottom portion 220 provided below the body portion 212.

This pressure-resistant bottle 210 is obtained by biaxial stretch blow molding of a preform manufactured by injection molding of polyethylene terephthalate (hereinafter abbreviated as PET). As a material of the preform, that is, the pressure resistant bottle 210, polypropylene (PP), polylactic acid (PLA), or various other thermoplastic resins can be used in addition to PET.

15 to 20, the bottom portion 220 has seven (a plurality of) leg portions 221 that extend from the central portion 220a to the peripheral edge portion 220b and project downward.

It is preferable to provide three or more leg portions 221 in order to stably stand up the pressure-resistant bottle 210, but the upper limit is about 15 from the viewpoint of formability. In order to effectively prevent buckling, the number of the leg portions 221 is preferably an odd number, more preferably 7 or 9.

16 and 17, the seven leg portions 221 are arranged at equal intervals along the peripheral edge portion 220b of the bottom portion 220.

As shown in FIGS. 17 and 18, each leg 221 includes a grounding surface 221a, an inner inclined surface 221b extending upward from the grounding surface 221a toward the central portion 220a, and a peripheral portion 220b side from the grounding surface 221a. And an outer inclined surface 221c extending upward. Among these, the inner inclined surface 221b has a substantially triangular shape when viewed from the bottom surface direction (see FIG. 17).

On the other hand, a flat surface 222 extending upward from the central portion 220a toward the peripheral portion 220b is formed between the leg portions 221. Each flat surface 222 constitutes a part of a dome-shaped curved surface that curves downward in a cross section from the central portion 220a to the peripheral portion 220b (see FIG. 18). In this case, each flat surface 222 is preferably made of a part of a spherical surface.

Further, a groove 251 is formed in each leg 221 from the central portion 220a side (inner inclined surface 221b) through the ground contact surface 221a toward the peripheral edge 220b side (outer inclined surface 221c). In the present embodiment, two grooves 251 are formed in every leg part 221, but the present invention is not limited to this, and the groove 251 may be provided only in specific (one or more) leg parts 221.

The number of grooves 251 is not limited, but is preferably 1 to 6 with respect to one leg 221. However, if the number of the grooves 251 formed in each leg 221 is one, the effect of the present embodiment to be described later becomes thin, and if the number is five or more, the moldability of the legs 221 may be slightly deteriorated. . For this reason, it is more desirable that the number of grooves 251 formed in each leg portion 221 is two to four.

Further, the peripheral edge 221 d of each leg 221 is retracted radially inward from the body 212 to form a peripheral step 226 together with the peripheral edge 222 a of each flat surface 222. That is, the peripheral step 226 is provided in an annular shape over the entire circumference of the bottom 220 (see FIG. 17), and the vertical cross section of the peripheral step 226 has an arc shape protruding downward (FIG. 18). reference).

The size of the pressure-resistant bottle 210 is not limited, and may be any size bottle. For example, in FIG. 18, when the capacity of the pressure-resistant bottle 210 is 500 ml, the diameter φ ₂ of the body portion 212 is set to 60 mm to 70 mm, and the bottom depth of the bottom portion 220 (that is, the grounding surface 221a of each leg portion 221 and the bottom portion 220 The distance h ₃ from the central portion 220a is preferably 2 mm to 6 mm. Further, in order to obscure the leg portion 221, the protrusion height h ₄ of each leg 221, it is preferable to lower the extent of not impairing the strength of the bottom portion 220. Specifically, the protruding height h ₄ of each leg 221 is preferably 10% to 20% of the diameter of the trunk.

Note for example when the capacity of the pressure-resistant bottle 210 is less than 350ml, if the diameter phi ₂ of 50mm to 68mm of the barrel 212, in the case of 1000ml is the diameter phi ₂ of the body 212 70 mm to 90 mm, of 1500ml barrel The diameter φ _{2 of} 212 is 80 mm to 100 mm, and the protrusion height h ₄ of the leg portion 221 is preferably 10% to 20% of the diameter φ ₂ of each trunk portion 212.

Further, in the cross section extending from the central portion 220a in the peripheral portion 220b, the radius of curvature R ₁ of the ground plane 221a of each leg 221 and 3mm or 7 mm, a curvature radius R ₂ of the peripheral step portion 226 be 1mm or 3mm preferable. Further, it is preferable that the thickness t ₂ of the body 212 is 0.1 mm to 0.5 mm, and the horizontal width w of the peripheral step 226 is 1 mm to 2 mm.

In FIG. 19, the depth d ₁ of each groove 251 is preferably 0.05 mm to 3 mm, more preferably 0.8 mm to 1.2 mm. When the depth d ₁ of the groove 251 is too shallow, the effect of providing the groove 251 is diminished, and when the depth d ₁ of the groove 251 is too deep, the moldability of the leg portion 221 may be slightly deteriorated.

In FIG. 19, the length of each groove 251 is L ₃ from the lowest point 221e of the ground surface 221a toward the peripheral edge 220b side (outer inclined surface 221c side), and the lowest point 221e of the ground surface 221a. If the length toward the central portion 220a side (inner inclined surface 221b side) was L ₄ from, it is preferable that the 1mm ≦ L ₃ ≦ 10mm and 0.5mm ≦ L ₄ ≦ 7mm. If the length of the groove 251 is too short, the effect of providing the groove 251 is reduced. On the other hand, when the length of the groove 251 is too long, the moldability of the leg portion 221 may be slightly deteriorated.

In FIG. 20, the width b ₁ of each groove 251 is preferably 0.2 mm to 5 mm. Further, when two or more grooves 251 are formed in each leg portion 221 as in the present embodiment, it is desirable that the interval a ₁ between the grooves 251 be equal to or greater than the width b ₁ of each groove 251 ( b ₁ ≦ a ₁ ). This is because if the distance a ₁ between the grooves 251 is smaller than the width b ₁ of each groove 251 (b ₁ > a ₁ ), the moldability may be deteriorated, and the area of the ground contact surface 221a is small. This is because the self-supporting property of the pressure resistant bottle 210 may be adversely affected.

First, the pressure-resistant bottle 210 is filled with a content liquid such as green tea, and then an inert gas such as nitrogen is filled in the head space and then closed. At this time, the inside of the pressure-resistant bottle 210 becomes a positive pressure (for example, 20 to 90 kPa) by the filled inert gas or content liquid.

When the inside of the pressure-resistant bottle 210 becomes a positive pressure, a force from the inside to the outside of the pressure-resistant bottle 210 acts, and pressure is applied from the upper side to the lower side at the bottom 220.

On the other hand, in the present embodiment, the bottom part 220 has seven leg parts 221 that extend from the central part 220a to the peripheral part 220b and project downward, and between the leg parts 221 from the central part 220a to the peripheral part. A flat surface 222 extending upward toward 220b is formed. Each flat surface 222 constitutes a part of a dome-shaped curved surface that curves downward in a cross section from the central portion 220a to the peripheral portion 220b. Therefore, even if the pressure bottle 210 has a positive pressure and a downward force is applied to the bottom 220, the bottom 220 is not easily deformed because the stress does not easily concentrate on the bottom 220. Further, the adjacent leg portions 221 and the flat surface 222 positioned between the leg portions 221 form a rib structure, and this also acts to prevent the deformation of the bottom portion 220.

Further, when the pressure inside the pressure-resistant bottle 210 is positive, a force is applied to cause the radius of curvature R ₁ of the ground contact surface 221a of the leg 221 to increase, but the groove 251 provided in the leg 221 works. Therefore, deformation of the curvature radius R ₁ can be suppressed. As a result, the total height change amount of the pressure bottle 210 can be further reduced. Moreover, not only can the change in the overall height of the pressure-resistant bottle 210 be suppressed, but it can also be prevented that the legs 221 are deformed and wrinkled due to the positive pressure.

That is, since the flat surface 222 has a dome shape protruding downward, even if the flat surface 222 of the bottom portion 220 starts to deform downward due to an increase in pressure in the pressure-resistant bottle 210, the entire bottom portion 220 is inverted. (That is, no buckling phenomenon occurs). Further, when the pressure in the pressure-resistant bottle 210 is increased, the body portion 212 acts to expand in the radial direction. However, since the peripheral step portion 226 is formed, the body portion 212 is difficult to expand in the radial direction.

By the way, let us consider a case where the pressure-resistant bottle 210 is placed on a retail shelf or placed on a table. In this case, a peripheral step 226 is formed between the bottom part 220 and the body part 212, and the peripheral part 221 d of each leg part 221 is retracted radially inward from the body part 212. As a result, the upper leg portion 221 is difficult to see and does not stand out. That is, the bottom portion 220 of the pressure-resistant bottle 210 has a leg portion 221 that protrudes downward, like the general petaloid-shaped bottom portion, but the leg portion 221 is inconspicuous. As a result, the bottom 220 appears as if it is a normal bottom in appearance.

Furthermore, in the present embodiment, as shown in FIG. 18, the trunk diameter φ ₂ is 60 mm to 70 mm, whereas the protruding height h ₄ of the leg 221 is shortened to 8 mm to 12 mm. This contributes to making the leg 221 inconspicuous.

As described above, according to the present embodiment, the bottom portion 220 has the plurality of leg portions 221 extending from the central portion 220a to the peripheral edge portion 220b and protruding downward, and between the leg portions 221 from the central portion 220a to the peripheral edge portion. A flat surface 222 extending upward toward 220b is formed. Each flat surface 222 constitutes a part of a dome-shaped curved surface that curves downward in a cross section from the central portion 220a to the peripheral portion 220b. Further, the peripheral edge portion 221 d of each leg portion 221 is retracted radially inward from the body portion 212 to form a peripheral step portion 226 together with the peripheral edge portion 222 a of each flat surface 222. Also, a groove 251 is formed in the leg portion 221 from the central portion 220a side to the peripheral portion 220b side through the ground contact surface 221a. Thereby, the strength of the bottom 220 is increased, and deformation (buckling or the like) of the bottom 220 can be prevented when the inside of the pressure-resistant bottle 210 is made positive.

Furthermore, the groove 251 provided in each leg part 221 can prevent the leg part 221 from being deformed and wrinkled when the inside of the bottle is made positive. Further, the leg portion 221 may have a dent or the like due to vibration when transporting the pressure-resistant bottle 210 filled with the content liquid, dropping the pressure-resistant bottle 210 by mistake, or dropping impact when selling with a vending machine. Although deformation may occur, such deformation can be prevented because the leg 221 is reinforced by the groove 251. Even if the leg portion 221 is deformed, there is an effect that the deformation is not conspicuous because of the groove 251.

In addition, according to the present embodiment, since the leg portion 221 of the bottom 220 is not noticeable when viewed from the outside of the pressure bottle 210, the appearance shape of the pressure bottle 210 is close to the appearance shape of a general bottle, and the consumer There is no possibility of misunderstanding the contents of the pressure bottle 210. That is, since a plastic bottle having a petaloid-shaped bottom is generally excellent in pressure resistance, many of them are used for filling and selling carbonated beverages. For this reason, consumers have a strong image that a plastic bottle having a petaloid-shaped bottom is filled with a carbonated beverage. According to the present embodiment, since the appearance shape of the pressure-resistant bottle 210 is close to the appearance shape of a general bottle, it is possible to prevent the consumer from misinterpreting the contents.

In addition, since the appearance shape of the pressure resistant bottle 210 is close to the appearance shape of a general bottle, the inside of the pressure resistant bottle 210 can be used as a non-positive pressure. For example, in some cases, green tea is filled and then nitrogen is filled to make the pressure-resistant bottle 210 a positive pressure so that it becomes a product for a vending machine. In other cases, the same pressure-resistant bottle 210 is filled with only green tea and is not automatic. It is also possible to make a product for a vending machine. Therefore, it is not necessary to prepare two types of bottle molds, and therefore there is no need to replace the molds in the bottle production factory, so that there is a secondary effect that the mold investment cost and the replacement time can be saved.

(Modification)
In addition, as shown in FIG. 21, you may form the recessed part 224 recessed upwards in the center part 220a of the bottom part 220. FIG. In this case, the same effect as that of the pressure resistant bottle 210 shown in FIGS. 15 to 18 can be obtained. Furthermore, by providing the recess 224, the strength of the bottom 220 is further increased, and the bottom 220 can be more effectively prevented from being deformed by the pressure in the pressure-resistant bottle 210.

Further, the pressure-resistant bottle 210 is formed by biaxial stretch blow molding of a preform (not shown), and the preform is manufactured by an injection molding method. A gate portion corresponding to the injection gate of the injection molding apparatus is formed on the bottom portion of the preform (the portion corresponding to the bottom portion 220 of the pressure-resistant bottle 210). In the modification shown in FIG. 21, since the recess 224 is formed in the bottom 220 of the pressure bottle 210, there is an effect of making the gate portion less noticeable.

Claims

In plastic bottles,
The mouth,
The torso,
With a bottom,
The bottom portion has a central portion and a plurality of legs disposed around the central portion and projecting downward,
A plastic bottle characterized in that one to six grooves extending along the radial direction of the bottom portion and retracting inward are formed in each leg portion.
Each leg has a grounding surface, a leg inner side surface provided on the inner side of the grounding surface, and a leg outer side surface provided on the outer side of the grounding unit,
2. The plastic bottle according to claim 1, wherein each groove extends from the inner surface of the leg portion to the outer surface of the leg portion through the ground contact surface.
2. The plastic bottle according to claim 1, wherein the bottom portion has 5 to 9 legs.
2. The plastic bottle according to claim 1, wherein each leg has a grounding surface, and the thickness of the grounding surface is 0.04 mm to 0.3 mm.
2. The plastic bottle according to claim 1, wherein each groove has a depth of 0.05 mm to 3 mm.
2. The plastic bottle according to claim 1, wherein each groove has a length of 3 mm to 25 mm.
2. The plastic bottle according to claim 1, wherein the width of each groove is 0.2 mm to 5 mm.
In each leg, the ratio of the total area (S g ) of the bottom surface of each groove to the total area (S T ) of the ground contact surface, the inner surface of the leg, and the outer surface of the leg is 2% or more and 50% or less. The plastic bottle according to claim 1.
2. The plastic bottle according to claim 1, wherein the plastic bottle has a structure in which a barrier layer having a gas barrier property and a light shielding property is laminated, or a structure in which a resin having a gas barrier property and a light shielding property is blended.
In pressure-resistant bottles,
The mouth,
The torso,
With a bottom,
The bottom portion extends from the central portion to the peripheral portion and protrudes downward, and has a plurality of leg portions each including a grounding surface, and a flat surface extending downward from the central portion toward the peripheral portion is formed between the respective leg portions. ,
The ground contact surface of each leg is formed in a curved surface in a cross section from the central part to the peripheral part,
A pressure-resistant bottle characterized in that a groove is formed in at least one leg portion from the central portion side to the peripheral portion side through the grounding surface.
The pressure-resistant bottle according to claim 10, wherein the number of grooves formed in each leg is 1 to 6.
The depth of each groove is 0.05 mm to 3 mm, The pressure-resistant bottle according to claim 10.
The pressure-resistant bottle according to claim 10, wherein at least two grooves are formed in each leg portion, and an interval between the grooves is equal to or greater than a width of each groove.
The length of each groove is 1 mm ≦ L 1 ≦ L 1 when the length from the lowest point on the ground plane toward the peripheral side is L 1 and L 2 is the length from the lowest point on the ground plane toward the center side. The pressure-resistant bottle according to claim 10, wherein 10 mm and 0.5 mm ≦ L 2 ≦ 7 mm.
The pressure-resistant bottle according to claim 10, wherein a reinforcing groove is formed on each flat surface so as to extend from the central portion side to the peripheral portion side and retract upward.
11. A pressure-resistant bottle according to claim 10, wherein a concave portion is formed at the center of the bottom portion so as to be retracted upward.
The pressure-resistant bottle according to claim 15, wherein a concave portion is formed in the center portion of the bottom portion so as to be recessed upward, and the bottom surface of the concave portion and the bottom surface of the reinforcing groove are flush with each other.
The pressure-resistant bottle according to claim 10, wherein each flat surface constitutes a part of a concave curved surface that curves upward in a cross section from the central portion toward the peripheral portion.
The pressure-proof bottle according to claim 10, wherein a protruding height of each leg portion from the flat surface on the ground contact surface is 1 mm to 3 mm.
The pressure-resistant bottle according to claim 10 or 15, wherein the pressure-resistant bottle has a structure in which a barrier layer having a gas barrier property and a light shielding property is laminated, or a structure in which a resin having a gas barrier property and a light shielding property is blended. .
In pressure-resistant bottles,
The mouth,
The torso,
With a bottom,
The bottom portion extends from the central portion to the peripheral portion and protrudes downward, and has a plurality of leg portions each including a grounding surface, and a flat surface extending upward from the central portion toward the peripheral portion is formed between the leg portions. ,
The peripheral part of each leg part is retracted radially inward from the trunk part to form a peripheral step part together with the peripheral part of each flat surface,
A pressure-resistant bottle characterized in that a groove is formed in at least one leg portion from the central portion side to the peripheral portion side through the grounding surface.
The pressure-resistant bottle according to claim 21, wherein the number of grooves formed in each leg portion is 1 to 6.
22. The pressure-resistant bottle according to claim 21, wherein the depth of each groove is 0.05 mm to 3 mm.
The pressure-resistant bottle according to claim 21, wherein at least two grooves are formed in each leg portion, and an interval between the grooves is equal to or greater than a width of each groove.
The length of each groove is 1 mm ≦ L 3 ≦ when the length from the lowest point on the ground plane toward the peripheral side is L 3 and the length from the lowest point on the ground plane toward the center is L 4. The pressure-resistant bottle according to claim 21, wherein 10 mm and 0.5 mm ≦ L 4 ≦ 7 mm.
The pressure-resistant bottle according to claim 21, wherein each flat surface constitutes a part of a dome-shaped curved surface that curves downward in a cross section from the central portion toward the peripheral portion.
The pressure-resistant bottle according to claim 21, wherein the bottom has an odd number of legs.
The pressure-resistant bottle according to claim 21, wherein the protruding height of each leg is 10% to 20% of the diameter of the trunk.
The pressure-resistant bottle according to claim 21, wherein a concave portion is formed in the center portion of the bottom portion so as to retract upward.
The pressure-resistant bottle according to claim 21, wherein the pressure-resistant bottle has a structure in which a barrier layer having a gas barrier property and a light shielding property is laminated, or a structure in which a resin having a gas barrier property and a light shielding property is blended.