JP6866641B2 - Plastic bottles and fillers - Google Patents

Description

The present invention relates to plastic bottles and fillers, and more particularly to lightweight plastic bottles and filler structures.

Plastic bottles, especially PET (PolyEthylene Terephthalate) bottles, are often used as containers for filling beverages and the like. The market size of large PET bottles is expanding due to the demand for stockpiling and the influence of diversification of daily life. However, the weight of a large PET bottle increases due to the large-capacity content to be filled, and the waist circumference becomes large, which makes it difficult to hold the bottle.

Patent Document 1 includes a mouth portion, a body portion, a shoulder portion, and a bottom portion, and the waist portion is located in the body portion substantially in the center in the height direction and the outer peripheral dimension is narrower than other portions. Is formed, and a large number of reinforcing grooves extending in the circumferential direction and retreating to the inside of the bottle are formed on the outer surface of the body mainly for increasing rigidity, and are approximately in the center of the height direction of the bottle. A plastic bottle is disclosed which is formed on the front side and the back side of the body portion so that the gripping recess portion located substantially in the center in the left-right direction overlaps the waist portion.

Japanese Unexamined Patent Publication No. 2016-094240

In the plastic bottle of Patent Document 1, the recess for gripping is located approximately in the center in the height direction of the body, and it makes sense to grip the vicinity of the center of gravity of the plastic bottle in terms of weight balance. There is. However, when pouring out the contents, it is better to grip the outer surface portion closer to the mouth portion for better operability of the position of the mouth portion. Further, Patent Document 1 does not describe or suggest gripping the outer surface portion, and has a reinforcing groove for increasing the rigidity with respect to the strength and the like that affect the ease of holding the outer surface portion. There is no particular description other than being formed. In particular, Patent Document 1 does not describe or suggest how easy it is to hold the outer surface of a plastic bottle whose wall thickness has been reduced to reduce weight. Further, the plastic bottle of Patent Document 1 has a weak buckling strength with respect to a load in the vertical direction in which the outer surface portion extends.

Therefore, an object of the present invention is to provide a square plastic bottle and a filler having good shapeability, rigidity and resistance to crushing, and light weight and excellent holdability.

In order to solve the above problems, the present invention sequentially has a mouth portion, a shoulder portion, a body portion, and a bottom portion in the axial direction, and the body portion has a plurality of plane portions and the plane portions adjacent to each other in the circumferential direction. In a plastic bottle having a square tube portion composed of connecting corners, the square tube portion has a groove that goes around the plastic bottle, the flat surface portion has a central portion and a peripheral portion, and the width of the groove is The peripheral portion is wider than the central portion, the central portion is wider than the corner portion, and the depth of the groove is characterized in that the peripheral portion is deeper than the central portion.

Further, the groove is characterized in that the value of the ratio of the depth at the central portion to the depth at the peripheral portion is 0.45 or more and 0.95 or less.

Further, the groove is characterized by having a curved shape in a cross section in the axial direction.

Further, the internal volume of the plastic bottle is 680 ml or more and 2500 ml or less.

Further, the value of the ratio of the mass to the volume of the plastic bottle is 0.0105 g / ml or more and 0.0300 g / ml or less.

Further, the filler according to the present invention is characterized by being composed of the above-mentioned plastic bottle and the liquid to be filled.

According to the present invention, a square tube having a mouth portion, a shoulder portion, a body portion, and a bottom portion sequentially in the axial direction, and the body portion is composed of a plurality of flat surfaces and corner portions connecting adjacent flat surfaces in the circumferential direction. In a plastic bottle having a portion, the square cylinder portion has a groove that goes around the plastic bottle, the flat surface portion has a central portion and a peripheral portion, and the width of the groove is wider in the peripheral portion than in the central portion. The central part is wider than the corner part, and the groove depth is deeper than the central part at the peripheral part, so it has good shapeability, is rigid but hard to collapse, and is lightweight yet easy to hold. An excellent square plastic bottle can be provided.

Further, according to the configuration in which the value of the ratio of the depth at the central portion to the depth at the peripheral portion is 0.45 or more and 0.95 or less, the groove is particularly flat with respect to the radial load. It is possible to make the central part of the plastic bottle less likely to bend and the plastic bottle to be more difficult to crush.

Further, according to the structure in which the groove has a curved shape in the cross section in the axial direction, it is difficult to bend the groove with respect to the load in the axial direction, and the strength of the plastic bottle can be further increased.

Further, according to the configuration in which the internal volume of the plastic bottle is 680 ml or more and 2500 ml or less, the shapeability is good, the plastic bottle is rigid and hard to be crushed, and the plastic bottle is lightweight and easy to hold. Large, square plastic bottles can be provided.

Further, according to the configuration in which the value of the ratio of the mass to the volume of the plastic bottle is 0.0105 g / ml or more and 0.0300 g / ml or less, the shapeability is good, and the plastic bottle has rigidity and is hard to be crushed. It is possible to provide a square plastic bottle that is easy to hold and has lighter weight.

Further, since the filler according to the present invention is composed of the above-mentioned plastic bottle and the liquid to be filled, it has good shapeability, is rigid but not easily crushed, and is lightweight and easy to hold. It is possible to provide a filler using a square plastic bottle having excellent rigidity.

It is a front view which showed the PET bottle as an example of the plastic bottle which concerns on this embodiment. It is a top view of a PET bottle. It is the front view which the peripheral groove is enlarged. FIG. 1 is a sectional view taken along line IV-IV of FIG. It is a bottom view of a PET bottle. It is sectional drawing of the peripheral groove of the PET bottle of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4.

The details of the embodiment of the present invention will be described below with reference to the drawings. First, the configuration of the plastic bottle according to the present embodiment will be described in detail. FIG. 1 is a front view showing a PET bottle 1 as an example of a plastic bottle according to the present embodiment, and FIG. 2 is a top view of the PET bottle 1. The PET bottle 1 is a so-called square bottle having a substantially square tube shape. The PET bottle 1 is formed by stretching a resin in the shape of a test tube called a preform, which is the prototype thereof. The PET bottle 1 has a mouth portion 10, a shoulder portion 20, a body portion 30, and a bottom portion 40 in this order in the axial direction thereof. The body portion 30 has a square cylinder portion including a plurality of flat surface portions 31 and a corner portion 32 connecting the flat surface portions 31 adjacent to each other in the circumferential direction of the PET bottle 1.

In the following, for convenience of explanation, the mouth portion 10 in which the contents are filled into the container in the state of FIG. 1 which is upright so that the axial direction of the PET bottle 1 extends vertically is referred to as the upper side. The PET bottle 1 has a total height H1 from the bottom 40 to the mouth 10.

The PET bottle 1 may be a square bottle having a square tube portion. The PET bottle 1 illustrated in FIG. 2 and the like has a substantially square cross section of a square tube portion orthogonal to the axial direction. However, the square bottle here may be one in which the cross section of the square tube portion is a substantially regular polygon, for example, a substantially regular dodecagon, and the plurality of flat surface portions 31 have different lengths in the circumferential direction. For example, it may be a rectangle.

The mouth portion 10 serves as a filling port and a spout for the contents, and the PET bottle 1 is sealed by attaching a lid (not shown) to the mouth portion 10. The mouth portion 10 may be crystallized until it is colored white by heating with a so-called crystallizing device so as to have the heat resistance required for filling the contents at a high temperature.

The upper side of the shoulder portion 20 is connected to the mouth portion 10, while the lower side thereof is connected to the body portion 30. The shoulder portion 20 is formed in the shape of a pyramid base cylinder that extends in the radial direction of the PET bottle 1 from the upper side to the lower side in the axial direction.

The PET bottle 1 has a ridge line 21 extending in the circumferential direction between the shoulder portion 20 and the body portion 30. The ridge line 21 has a function of absorbing the axial load of the PET bottle 1. The ridge line 21 undulates in the axial direction and is located closest to the body portion 30 in the corner portion 32. The shoulder portion 20 in the region above the corner portion 32 is likely to be bent by an axial load as it is. However, due to the configuration in which the ridge line 21 is located on the side of the body portion 30 most in the corner portion 32, the load is dispersed without being concentrated on the portion that is easily bent, and the buckling strength of the PET bottle 1 is increased.

A plurality of flat plate-shaped cut surfaces are formed on the shoulder portion 20. Then, the side serving as the boundary of these cut surfaces mainly extends in the axial direction, and thus functions as a support column for the load in the axial direction of the PET bottle 1.

On the flat surface portion 31, an isosceles triangular region long in the axial direction with the ridge line 21 as the base is formed by the ridge line 22 protruding toward the outside of the PET bottle 1. Further, inside the isosceles triangle region, three triangular panels are formed by three ridges 23 protruding inward of the PET bottle 1. By forming the shoulder portion 20 in the region above the flat surface portion 31 in this manner, the strength against the axial and radial loads of the PET bottle 1 is increased, and the pressure inside the PET bottle 1 is changed. Its shape is maintained without being distorted.

Further, the shoulder portion 20 has a ridge line 24 that protrudes toward the outside of the PET bottle 1 and extends axially from the center in the circumferential direction at the corner portion 32. When the ridge line 24 is pushed, it tends to be dented inside the PET bottle 1. Further, a ridge line 25 protruding toward the outside of the PET bottle 1 is also formed between the side of the mouth portion 10 of the ridge line 24 and the boundary between the flat surface portion 31 and the corner portion 32 of the ridge line 21. Therefore, a fan-shaped sinking panel 26 having a ridge line 24 that divides the central angle into two is formed on the shoulder portion 20 in the region above the corner portion 32. The ridge line 25 prevents the deformation when the ridge line 24 is pressed from spreading to the region outside the fan shape.

A label such as a shrink label or a roll label on which information on the contents of the PET bottle 1 and a pattern for enhancing the design is printed is packaged in the body portion 30. A biaxially stretched polystyrene film or the like having good heat shrinkage is used for the shrink label attached by heat shrinkage. Since the shrink label is made of a different material from the PET bottle 1, it is separated when it is recycled after the PET bottle 1 is used. Since the shrink label is mainly attached by being hooked on the corner portion 32, it becomes easy to peel off by removing the catch on the corner portion 32. When the ridge line 24 is pushed, a gap is formed between the PET bottle 1 and the label in the vicinity of the corner portion 32, which makes it easier to grasp the label and partially removes the catch of the corner portion 32, so that the label can be easily peeled off. be able to.

The plurality of cut surfaces formed on the shoulder portion 20 illustrated in FIG. 1 and the like are formed in a flat plate shape, and are not curved to the outside or the inside of the PET bottle 1. However, if the shoulder portion 20, particularly the fan-shaped sinking panel 26, is configured to be curved outward from the PET bottle 1, a wider gap is created between the PET bottle 1 and the label, making the label easier. It can be peeled off.

Although the shoulder portion 20 is not limited to the above-described configuration, it is preferable that the shoulder portion 20 has a ridge line 21 and a ridge line 24 in terms of the strength and shape maintenance function of the PET bottle 1, the ease of peeling off the label, and the like.

The body portion 30 has an upper square cylinder portion 50 as a square cylinder portion. The upper square tube portion 50 illustrated in FIG. 2 and the like has four flat surface portions 31 and four corner portions 32 having the same shape as each other. The circumferential length of the flat surface portion 31 is, for example, 31.6 mm.

The corner portion 32 is curved outward in the radial direction. The upper square cylinder portion 50 has the same radial dimension in the upper and lower directions, and has a substantially regular square cylinder shape as a whole. The upper square tubular portion 50 has a shape close to a cylinder by having a corner portion 32 that curves outward, and its buckling strength is improved. The radius of curvature of the corner portion 32 is not particularly limited. The corner portion 32 has, for example, a radius of curvature of 19 mm.

The upper square tube portion 50 is configured to have a diagonal distance D1 and a facing distance D2. The diagonal distance D1 is larger than the face-to-face distance D2. The diagonal distance D1 is, for example, 82.5 mm, and the face-to-face distance D2 is, for example, 69.4 mm.

FIG. 3 is an enlarged front view of the peripheral groove 51. The upper square tube portion 50 has a plurality of annular peripheral grooves 51 that are recessed inward in the radial direction and cross the flat surface portion 31 and the corner portion 32 in the circumferential direction. The peripheral groove 51 has a function of increasing the side wall strength, which is the strength to withstand a load in the radial direction. Further, the peripheral groove 51 acts as a cushion against a load in the axial direction, and has a function of preventing buckling of the body portion 30. By increasing the strength of the side wall of the upper square cylinder portion 50, a moderate repulsive force is generated when the upper square cylinder portion 50 is gripped, and the ease of holding the PET bottle 1 is improved. Further, the strength of the side wall of the upper square cylinder portion 50 is increased, so that the label can be easily attached to the upper square cylinder portion 50.

The peripheral groove 51 may have a substantially tapered or V-shaped cross section in the axial direction having a flat bottom surface. However, it is preferable that the peripheral groove 51 has a curved shape such as an arc shape in a cross section in the axial direction and does not have an angle. The PET bottle 1 is configured so that the peripheral groove 51 does not have an angle in the axial cross section, so that the PET bottle 1 does not bend with respect to an axial load and the buckling strength is further increased.

Among the flat surface portions 31, the peripheral groove 51 has different dimensions in the central portion 31 m and in the peripheral portion 31 p. Further, the peripheral groove 51 may be configured so that the dimensions of the flat surface portion 31 and the corner portion 32 are different.

Here, the boundary between the central portion 31m and the peripheral portion 31p does not have to be strictly defined, and the dimensions of the peripheral groove 51 differ between the vicinity of the center in the circumferential direction of the flat surface portion 31 and the vicinity outside the center. It suffices if the PET bottle 1 is configured with such a tendency. The boundary between the central portion 31m and the peripheral portion 31p may be, for example, a region in which the flat surface portion 31 is divided into three equal parts in the circumferential direction as an approximate reference.

FIG. 3 shows a central portion width Wm which is the width at the central portion 31 m of the peripheral groove 51, a peripheral portion width Wp which is the width at the peripheral portion 31p, and a corner portion width Wc which is the width at the corner portion 32. .. The peripheral groove 51 has a wide portion 51b and a narrow width portion 51n in the flat surface portion 31. For example, the shapeability of the PET bottle 1 can be improved by setting the wide portion 51b as a portion that is difficult to form, such as a small angle between the outer peripheral surface of the flat surface portion 31 and the peripheral groove 51.

If the width of the peripheral groove 51 is too large, the strength against the load in the axial direction decreases and the amount of compressive deformation increases. On the other hand, if the width of the peripheral groove 51 is too small, the shapeability of the body portion 30 will not be good. Therefore, the width of the peripheral groove 51 is appropriately designed within a range in which the shapeability is good and the strength against the load in the axial direction is secured. The peripheral groove 51 may be a narrow portion 51n at the central portion 31m and a wide portion 51b at the peripheral portion 31p. With this configuration, the depth of the peripheral groove 51 can be made small in the central portion 31 m and large in the peripheral portion 31 p, and the shapeability at that time can be made better. .. The central width Wm is, for example, 3.0 mm, the peripheral width Wp is, for example, 3.9 mm, and the corner width Wc is, for example, 2.7 mm.

FIG. 4 is a sectional view taken along line IV-IV of FIG. That is, FIG. 4 shows a surface in which the upper square cylinder portion 50 is cut at the center of the peripheral groove 51 in the axial direction in the direction orthogonal to the axial direction. The peripheral groove 51 has a substantially rounded square cross section, and has a central depth Dm which is a depth at the central portion 31 m, a peripheral portion depth Dp which is a depth at the peripheral portion 31p, and a corner portion 32. It is configured to have a corner depth Dc, which is the depth in.

The peripheral groove 51 has a smaller depth at the central portion 31 m of the flat surface portion 31 than at the peripheral portion 31 p of the flat surface portion 31. That is, the central depth Dm of the peripheral groove 51 is smaller than the peripheral depth Dp. The peripheral groove 51 has a function of increasing the rigidity of the body portion 30 even in the PET bottle 1 whose wall thickness is thinned and the weight is reduced because the peripheral portion depth Dp is made larger. On the other hand, the peripheral groove 51 imparts flexibility to the central portion 31m of the flat surface portion 31 by forming the central portion depth Dm to be smaller, so that the flat surface portion 31 of the PET bottle 1 can be viewed from the outside in the radial direction. It has a function to prevent it from collapsing without bending even if it receives the force of. The central depth Dm is, for example, 1.5 mm, and the peripheral depth Dp is, for example, 2.1 mm. The peripheral grooves 51 having different depths in the flat surface portion 31 are configured to draw a smooth curve in the circumferential direction so that the depths change continuously.

If the difference between the central depth Dm and the peripheral depth Dp is too small, the above-mentioned effect will not be exhibited. On the other hand, if the depth Dm of the central portion is too small with respect to the depth Dp of the peripheral portion, the strength against the load in the axial direction decreases, and the peripheral portion 31p tends to be crushed or the central portion 31m becomes too soft. As a result, the ease of holding is reduced. These phenomena become so severe that the body portion 30 is made thin in order to reduce the weight of the PET bottle 1. Therefore, the peripheral groove 51 preferably has a value of the ratio of the central portion depth Dm to the peripheral portion depth Dp of 0.45 or more and 0.95 or less. By being configured in this way, the peripheral groove 51 increases the rigidity of the peripheral portion 31p, makes it difficult for the central portion 31m of the flat surface portion 31 to bend particularly with respect to a load in the radial direction, and makes the PET bottle 1 more flexible. It can be made hard to collapse.

As described above, the peripheral groove 51 has a wide portion 51b and a narrow width portion 51n in the flat surface portion 31, and is smaller in the central portion 31 m of the flat surface portion 31 than in the peripheral portion 31p of the flat surface portion 31. Has depth. By being configured in this way, the PET bottle 1 has good shapeability, is rigid and is not easily crushed, and is lightweight and has excellent ease of holding.

The peripheral groove 51 preferably has a smaller depth at the corner portion 32 than at the central portion 31 m. That is, the corner depth Dc of the peripheral groove 51 is preferably smaller than the central depth Dm.

The peripheral groove 51 configured in this way has a function of making it difficult to bend with respect to an axial load while maintaining rigidity at the corner portion 32. That is, the peripheral groove 51 can increase the strength of the corner portion 32 and further increase the strength of the PET bottle 1 with respect to the load in the axial direction. Further, since the peripheral groove 51 increases the side wall strength in the flat surface portion 31, the PET bottle 1 can be stably loaded sideways. Further, since the peripheral groove 51 has a small depth at the corner portion 32 which is a distance from the radial center of the PET bottle 1 in the radial direction, the shape is not severely uneven and the shapeability is good. is there.

At the corner portion 32, a peripheral groove 51 is formed so that the depth is minimized at the center in the circumferential direction. The peripheral groove 51 having different depths in the corner portion 32 and the flat surface portion 31 is configured to draw a smooth curve in the circumferential direction so that the depth changes continuously. The corner depth Dc is, for example, 0.9 mm.

The peripheral groove 51 preferably has a configuration in which the depth and the width correspond to each other. According to such a configuration, the shapeability of the PET bottle 1 can be improved. At that time, the width of the peripheral groove 51 is designed with reference to the peripheral portion 31p of the flat surface portion 31 having the maximum depth, so that the body portion 30 does not have a severely uneven shape and its shapeability. Can be good.

The upper square cylinder portion 50 of the PET bottle 1 illustrated in FIG. 1 and the like has six peripheral grooves 51. Here, it is preferable that the peripheral grooves 51 are arranged at a certain distance from each other. In particular, each of the plurality of peripheral grooves 51 configured in this way can more evenly distribute the load in the radial direction and make the PET bottle 1 more difficult to be crushed. Therefore, as illustrated in FIG. 1 and the like, it is preferable that the six peripheral grooves 51 have the same depth and width dimensions, and are arranged in parallel and at equal intervals. ..

If the upper square cylinder portion 50 of the PET bottle 1 has a sufficient wall thickness, the peripheral groove 51 may be configured to extend obliquely with respect to the axial direction.

In this way, the upper square tubular portion 50 having a plurality of peripheral grooves 51 having a narrow width portion 51n at the central portion 31 m has a flat portion long in the axial direction on the surface thereof due to the central portion 31 m of the flat surface portion 31. Unevenness is suppressed. For this reason, it becomes easier to attach the label to the upper square cylinder portion 50, and the appearance defect when the label is attached is less likely to occur, and the manufacturing efficiency of the PET bottle 1 and the display effect (advertising effect) of the label are improved. Can be done.

Note that FIG. 1 and the like show an example in which six peripheral grooves 51 are formed in the upper square cylinder portion 50. However, the number thereof is not particularly limited, and is appropriately designed depending on the axial length of the upper square cylinder portion 50, the depth and width of the peripheral groove 51, and the like. Further, the depths of all the peripheral grooves 51 are not designed to be the same, and the depth at the upper side, for example, two peripheral grooves 51, particularly the peripheral portion 31p, is smaller than the depth of the lower peripheral groove 51. It may be said. With this configuration, it is possible to disperse the stress concentration in the upper peripheral groove 51, which is likely to be deformed with respect to the axial load.

When the square bottle is long in the axial direction, the side wall strength is increased by increasing the number of peripheral grooves 51. However, as the number of peripheral grooves 51 increases, the amount of compressive deformation due to the axial load becomes larger. Therefore, the PET bottle 1 is configured to have a cylindrical portion 60 having a circular cross section orthogonal to the axial direction in order to further suppress the amount of compressive deformation with respect to the load in the axial direction and further strengthen the buckling strength. Is also good. In that case, it is preferable that the cylindrical portion 60 also has both ease of holding and strength. The PET bottle 1 can be used properly, such that the cylindrical portion 60 is gripped when opening the cap (not shown) of the PET bottle 1, and the upper square cylinder portion 50 is gripped when the contents are poured out. It may be configured.

The cylindrical portion 60 has a constricted portion 61. The constricted portion 61 is formed by narrowing the body portion 30 in the radial direction. The constricted portion 61 can effectively increase the buckling strength. Further, the constricted portion 61 has a short waist circumference, so that it is easy to grip. Therefore, the constricted portion 61 also functions as a grip portion, making it easier to hold the PET bottle 1.

The constricted portion 61 has a rib 62 extending in the axial direction. The rib 62 projects outward in the radial direction of the PET bottle 1. The rib 62 has a function as a support for both the axial and radial loads of the PET bottle 1. A plurality of ribs 62 are arranged in the circumferential direction of the constricted portion 61. The constricted portion 61 in which the plurality of ribs 62 are arranged has improved strength and is less likely to be deformed, so that the PET bottle 1 can be easily held. Further, the rib 62 can be hooked on the gripped finger to make it easier to hold the PET bottle 1.

As illustrated in FIG. 1 and the like, the rib 62 has a twist in the circumferential direction. Since the rib 62 has a twist, it is more easily applied to the gripped finger, and the PET bottle 1 is more easily held. Further, since the rib 62 has a twist, the load in the axial direction is dispersed in the circumferential direction, and the buckling strength of the PET bottle 1 can be increased. The rib 62 is tilted at 45 degrees with respect to the vertical line, for example.

At the upper end of the constricted portion 61, adjacent ribs 62 are connected by an upper side 63. The upper side 63 is curved in an arc shape toward the upper side. Similarly, at the lower end of the constricted portion 61, adjacent ribs 62 are connected by a lower side 64. The lower side 64 is curved in an arc shape toward the lower side. By forming the upper side 63 and the lower side 64, the cylindrical portion 60 is less likely to be deformed, and the PET bottle 1 can be easily held. Further, the curved upper side 63 and lower side 64 can absorb the axial load of the PET bottle 1 and increase the buckling strength. The two adjacent ribs 62 are opposite sides, and the opposite side, the upper side 63, and the lower side 64 form an oval panel 65. Therefore, the constricted portion 61 is formed in a tubular shape in which a plurality of panels 65 curved inward in the radial direction are connected in the circumferential direction.

The region above the upper side 63 and the region below the lower side 64 are cylindrical with the same upper and lower diameters. Although there is no limitation on the size relationship between this cylinder and the upper square cylinder portion 50 in the radial direction of the PET bottle 1, the cylindrical portion 60 is an inscribed circle of the upper square cylinder portion 50 from the viewpoint of loading efficiency of the PET bottle 1 and the like. Is preferable.

The panel 65 including the rib 62 has a curved surface shape so as to reduce the diameter toward the center in the axial direction starting from the upper side 63 and the lower side 64. The rib 62 is configured so that the distance from the center in the radial direction is maximized in an arbitrary cross section orthogonal to the axial direction of the constricted portion 61. That is, the cross section of the outer circumference of the constricted portion 61 is a polygon with the rib 62 as the apex. The PET bottle 1 configured in this way has both light weight and high strength against external force, and is easy to hold.

The number of panels 65 may be appropriately designed from the viewpoint of improving the ease of holding while maintaining the strength of the PET bottle 1. The panel 65 of the PET bottle 1 illustrated in FIG. 1 and the like is composed of six panels having the same shape.

The axial length of the constricted portion 61 may be designed from the viewpoint of maintaining the strength while maintaining the ease of holding the PET bottle 1, and may be at least longer than the width of the first finger. In the configuration of the rib 62 having a twist in the circumferential direction, the rib 62 having a curved curved shape, and the panel 65, for example, the first finger and the third finger used for gripping are constricted. The PET bottle 1 fits snugly on the part 61 and is easy to hold. The axial length of the cylindrical portion 60 does not necessarily have to fit the second and fourth fingers along the third finger, and is, for example, 38.5 mm.

FIG. 5 is a bottom view of the PET bottle 1. When the body portion 30 has a cylindrical portion 60, it is preferable that the body portion 30 has a lower square cylinder portion 70 composed of a flat surface portion 31 and a corner portion 32, similarly to the upper square cylinder portion 50. Then, the facing distance D2 of the upper square cylinder portion 50 and the lower square cylinder portion 70 is formed to be the same, so that each of the flat surface portions 31 of the upper square cylinder portion 50 and the lower square cylinder portion 70 becomes a grounding portion. Therefore, the PET bottle 1 can be stably placed in a horizontal state in which the axial direction is horizontal. Further, since the facing distance D2 of the upper square cylinder portion 50 and the lower square cylinder portion 70 is formed to be the same, a plurality of PET bottles 1 can be stably stored when they are packed in a box.

Two peripheral grooves 71 are formed in the lower square tube portion 70 illustrated in FIG. 1 and the like. The lower square tube 70 is not often gripped, and although rigidity is required, the importance of ease of holding is not as high as that of the upper square tube 50. Therefore, the peripheral groove 71 of the lower square cylinder portion 70 does not necessarily have to have a configuration having the characteristics of the peripheral groove 51. That is, the central depth Dm of the peripheral groove 71 does not have to be smaller than the peripheral depth Dp. However, it is preferable that the lower square tube portion 70 is also provided with the peripheral groove 71 having the same configuration as the peripheral groove 51, so that rigidity and resistance to crushing can be imparted. Therefore, the lower square cylinder portion 70 may have the same configuration as the upper square cylinder portion 50. With this configuration, for example, when the PET bottle 1 is gripped by both hands, the lower square cylinder portion 70 is prevented from being crushed by the attached hand, and it is easy to hold the PET bottle 1.

The PET bottle 1 is formed to have a lower height H2 from the bottom portion 40 to the lower end of the upper square cylinder portion 50. If the value of the ratio of the lower height H2 to the total height H1 (H2 / H1) is too small, the cylindrical portion 60 and the lower square cylinder portion 70 cannot be formed below the upper square cylinder portion 50. Depending on the capacity (height) of the PET bottle 1, it becomes difficult to maintain the strength. On the other hand, if H2 / H1 is too large, the upper square cylinder portion 50 becomes small and the area for displaying the label becomes narrow. Further, if the area of the upper square cylinder portion 50 is narrowed, the place where the PET bottle 1 is gripped is limited, and the operability thereof is deteriorated. Therefore, it is preferable that the value (H2 / H1) of the ratio of the lower height H2 to the total height H1 of the PET bottle 1 is 0.20 or more and 0.49 or less. The value (H2 / H1) of the ratio of the lower height H2 to the total height H1 is, for example, 0.39.

Since the upper square cylinder portion 50 has rigidity and is not easily crushed, and has excellent ease of holding while having light weight, the region can be expanded below the center of gravity of the PET bottle 1. Therefore, in the PET bottle 1, the upper square cylinder portion 50 can be used as the grip portion and the area for mounting the label can be widened in a wide range.

It is preferable that the upper square cylinder portion 50, the lower square cylinder portion 70, and the cylindrical portion 60 are connected to each other via a connecting groove 80 that is recessed in the radial direction and extends in the circumferential direction, respectively. The connecting groove 80 and the connecting groove 85 have a function of receiving an axial load as a cushion and preventing bending of the connecting portion. Further, the connecting groove 80 and the connecting groove 85 have a function of increasing the side wall strength in the vicinity of the connecting portion. The connecting groove 80 and the connecting groove 85 have a circular cross section orthogonal to the axial direction, and have a substantially tapered shape having a flat bottom surface in the axial direction. The articulated groove 80 and the articulated groove 85 may have an arc-shaped or V-shaped cross section in the vertical direction.

If the depth of the connecting groove 80 and the connecting groove 85 is too shallow, it becomes difficult to increase the buckling strength. On the other hand, if the depth of the connecting groove 80 and the connecting groove 85 is too deep, the shapeability of the PET bottle 1 at the time of molding tends to decrease. The depth of the connecting groove 80 and the connecting groove 85 is preferably 0.05 or more and 0.07 or less, and more preferably 0.03, in terms of the ratio value of the cylindrical portion 60 to the maximum outer diameter. preferable.

If the width of the connecting groove 80 and the connecting groove 85 is too wide, it becomes difficult to increase the side wall strength. On the other hand, if the widths of the connecting groove 80 and the connecting groove 85 are too narrow, the shapeability of the PET bottle 1 at the time of molding tends to decrease. The width of the connecting groove 80 and the connecting groove 85 is preferably 0.5 or more and 5.0 or less as a ratio value to the depth of the connecting groove 80 and the connecting groove 85.

A chamfered portion 52 may be formed at the corner portion 32 of the upper square cylinder portion 50 in contact with the upper end of the connecting groove 80. Similarly, the chamfered portion 72 may be formed at the corner portion 32 of the lower square cylinder portion 70 in contact with the lower end of the connecting groove 85. Further, a chamfered portion 73 may be formed at a corner portion 32 at the lower end of the lower square cylinder portion 70. By forming the chamfered portion 52, the chamfered portion 72, and the chamfered portion 73, the axial load is distributed to the easily bent corner portion 32 without being concentrated, and the buckling strength of the PET bottle 1 is increased.

The bottom portion 40 is connected to the lower side of the lower square cylinder portion 70 of the body portion 30. The bottom portion 40 has a corner portion 41, a bottom wall 42, and a dome 43. The corner portion 41 is curved toward the lower side in the axial direction of the PET bottle 1 and the outer side in the radial direction. The substantially flat plate annular bottom wall 42 extends in the direction perpendicular to the body portion 30 and serves as a ground plane for the PET bottle 1.

The dome 43 is formed in a hollow hemisphere that curves toward the inside (upper side in the axial direction) of the PET bottle 1. The dome 43 has a function of preventing deformation due to changes in the temperature of the contents of the PET bottle 1 and the internal pressure. The angle of inclination of the dome 43 with respect to the ground plane may be designed within a range in which pressure and the like are effectively dispersed to prevent deformation and shapeability is good. As illustrated in FIG. 1, the dome 43 may be configured to project in a plurality of steps toward the upper side in the axial direction on the inner side in the radial direction.

The dome 43 illustrated in FIG. 5 has eight radial ribs 44 and eight circumferential ribs 45, respectively. Each of the radial ribs 44 extends radially in bottom view. The circumferential rib 45 extends radially between adjacent radial ribs 44 in a bottom view. The radial rib 44 is formed so as to project upward in the axial direction from the dome 43. On the contrary, the circumferential rib 45 is formed so as to project downward in the axial direction from the dome 43. Both the radial rib 44 and the circumferential rib 45 have a function of reinforcing the dome 43. The radial ribs 44 and the circumferential ribs 45 may be formed so as to protrude within a range that does not cause whitening due to overstretching or deterioration of the shapeability of the PET bottle 1.

A concave receiving portion 46 may be formed at the radial center of the bottom portion 40, that is, at the top of the dome 43. The receiving portion 46 is configured so that the tip of the drawing rod enters when the PET bottle 1 is stretched and molded from the prototype preform. The receiving portion 46 has a function of preventing the bottom portion 40 from being eccentric in the radial direction due to the stretching rod.

The bottom portion 40 is not limited to the example shown in FIG. 5, and may be configured so as not to be easily deformed downward even when positive pressure is applied in a state where it is easily deformed by heat. As a result, it is possible to prevent the full filling capacity of the PET bottle 1 from being larger than the design value and the change in the internal pressure becoming larger due to the increase in the proportion of air in the container. The dome 43 is designed to be maintained at least above the ground plane of the PET bottle 1 even if it is deformed by heat. As a result, the bottom portion 40 is prevented from protruding outward (lower side) from the bottom wall 42, and the PET bottle 1 can be prevented from rattling or tipping over.

The PET bottle 1 according to the present embodiment is not limited by size and can be applied to various sizes. However, a larger bottle is preferable because the effect of the configuration of the PET bottle 1 according to the present embodiment is more exhibited. For example, the internal volume of the PET bottle 1 is preferably 680 ml or more and 2500 ml or less, and more preferably 850 ml to 2000 ml. The total height H1 of the PET bottle 1 may be 190 mm or more and 320 mm or less, and the facing distance D2 of the body portion 30 may be 60 mm or more and 100 mm or less.

Further, the PET bottle 1 according to the present embodiment can be suitably used for a lightweight bottle. In particular, from the viewpoint of maintaining the strength of the PET bottle 1 while increasing the absorption amount of changes in the internal pressure while having light weight, the value of the ratio of the mass to the internal volume of the PET bottle 1 is 0.0105 g / ml or more. It is preferably 0.0300 g / ml or less.

Examples of the material of the plastic bottle for which PET bottle 1 is exemplified include polyolefins such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-vinyl alcohol copolymer, and plants. Various plastics that can be blow-molded, such as polylactic acid, can be used. However, it is preferable that the plastic bottle is mainly composed of polyester such as polyethylene naphthalate, particularly polyethylene terephthalate. In addition, various additives such as a colorant, an ultraviolet absorber, a mold release agent, a lubricant, a nucleating agent, an antioxidant, and an antistatic agent are blended in the above-mentioned resin as long as the quality of the molded product is not impaired. be able to.

As the ethylene terephthalate-based thermoplastic resin constituting the PET bottle 1, the ethylene terephthalate unit occupies most of the ester repeating portion, generally 70 mol% or more, and the glass transition point (Tg) is 50 ° C. or higher and 90 ° C. or higher. It is preferable that the melting point (Tm) is in the range of 200 ° C. or higher and 275 ° C. or lower. As an ethylene terephthalate-based thermoplastic polyester, polyethylene terephthalate is particularly excellent in terms of pressure resistance, etc., but in addition to the ethylene terephthalate unit, it is composed of dibasic acids such as isophthalic acid and naphthalenedicarboxylic acid, and diols such as propylene glycol. Copolymerized polyesters containing a small amount of ester units can also be used.

Polyethylene terephthalate has the highest production volume among thermoplastic synthetic resins. The polyethylene terephthalate resin has various properties such as excellent heat resistance, cold resistance, chemical resistance, and abrasion resistance. Furthermore, polyethylene terephthalate resin has a lower proportion of petroleum in its raw material than other plastics, and can be recycled. As described above, according to the structure containing polyethylene terephthalate as a main component, a material having a large amount of production can be used, and various excellent properties thereof can be utilized.

Polyethylene terephthalate is obtained by condensation polymerization of ethylene glycol (ethane-1,2-diol) and purified terephthalic acid. It is preferable that at least one of a germanium compound, a titanium compound, and an aluminum compound is used as the polymerization catalyst of polyethylene terephthalate. By using these catalysts, it is possible to form a container having higher transparency and excellent heat resistance than the antimony compound is used.

A plastic bottle can be produced by blow molding a preform obtained by injection molding the above-mentioned material. Then, by using polyethylene terephthalate as a material, a PET bottle 1 as an example of the plastic bottle according to the present embodiment is produced. Then, the filler is composed of the PET bottle 1 and the liquid to be filled. The filler is manufactured by filling a liquid such as a beverage or a seasoning from the mouth 10 of the PET bottle 1 and sealing it with a lid (not shown) attached to the mouth 10.

As described above, the PET bottle 1 has a mouth portion 10, a shoulder portion 20, a body portion 30, and a bottom portion 40 in that order in the axial direction, and the body portions 30 are adjacent to each other in the plurality of plane portions 31 and in the circumferential direction. The upper square cylinder portion 50 including a corner portion 32 connecting the flat surface portions 31 has an upper square cylinder portion 50, the upper square cylinder portion 50 has a peripheral groove 51 that orbits the PET bottle 1, and the peripheral groove 51 has a wide width in the flat surface portion 31. It has a portion 51b and a narrow width portion 51n, and has a depth smaller in the central portion 31m of the flat surface portion 31 than in the peripheral portion 31p of the flat surface portion 31. According to such a configuration, it is possible to provide a square PET bottle 1 having good shapeability, rigidity and resistance to crushing, light weight and excellent holding.

Further, the filler is composed of the PET bottle 1 and the liquid to be filled. According to such a configuration, a filler using a square PET bottle 1 having good shapeability, rigidity and resistance to crushing, light weight and excellent holding property is provided. be able to.

The PET bottle 1 and the filler according to the present embodiment may have a configuration different from that described above except for the peripheral groove 51 formed in the upper square cylinder portion 50 as the square cylinder portion. ..

Hereinafter, the present disclosure will be described in more detail and concretely with reference to Examples. However, the present disclosure is not limited to the following examples.

<Material and manufacturing method>
[Example 1]
A PET bottle 1 made of 24 g of polyethylene terephthalate and having a full filling capacity of 940 ml as shown in FIG. 1 and the like was used. The depth Dm at the center of the PET bottle 1 was 1.5 mm, and the depth Dp at the periphery was 2.1 mm. The PET bottle 1 was filled with 900 ml of water and then closed with a cap (not shown) to prepare a filler.

The PET bottle 1 and the filler according to the first embodiment have a peripheral groove 51 around the PET bottle 1 in the upper square cylinder portion 50, and the peripheral groove 51 has a wide portion 51b and a narrow width in the flat surface portion 31. It had features according to the present embodiment, such as having a portion 51n and having a depth smaller than that of the peripheral portion 31p of the flat portion 31 at the central portion 31m of the flat portion 31.

[Comparative Example 1]
FIG. 6 is a cross-sectional view of the peripheral groove 251 of the PET bottle 200 corresponding to FIG. 3 of the first embodiment. Comparative Example 1 was the same as that of Example 1 except that the PET bottle 200 having the peripheral groove 251 shown in FIG. 6 having a shape different from that of the peripheral groove 51 was used. A peripheral groove 251 that goes around the PET bottle 200 was formed in the upper square cylinder portion 250 of the body portion 230 of the PET bottle 200. However, the peripheral groove 251 had the same depth in both the central portion 231 m of the flat surface portion 231 and the peripheral portion 231 p of the flat surface portion 231. In the PET bottle 200 of Comparative Example 1, the depth of the peripheral groove 251 was set to 2.1 mm, which is the same as the peripheral depth Dp of the PET bottle 1 of Example 1. Therefore, the filler according to Comparative Example 1 did not have the characteristics according to the present embodiment.

[Comparative Example 2]
Comparative Example 2 was the same as Comparative Example 1 except that the weight was 28 g. Therefore, the filler according to Comparative Example 2 also did not have the characteristics according to the present embodiment.

[Comparative Example 3]
In Comparative Example 3, the depth of the peripheral groove 251 was the same as that of Comparative Example 1 except that the depth of the peripheral groove 251 was 1.5 mm, which is the same as the depth Dm of the central portion in the PET bottle 1 of Example 1. Therefore, the filler according to Comparative Example 3 also did not have the characteristics according to the present embodiment.

[Comparative Example 4]
Comparative Example 4 was the same as Comparative Example 3 except that it weighed 28 g. Therefore, the filler according to Comparative Example 4 also did not have the characteristics according to the present embodiment.

<Evaluation method>
(Lightweight)
It was determined whether or not the weight reduction could be achieved by the mass of each PET bottle of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. In determining the weight reduction, a threshold value of greater than or less than 24 g was set. Table 1 shows the results of the evaluation of the lightness of each PET bottle, and is indicated by ◯: with lightness and ×: without lightness.

(Wall side strength test)
The side wall strengths of the upper square cylinder portion 50 and the upper square cylinder portion 250 when the fillers of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are laid horizontally are It was measured. A tester manufactured by AGR, TOP LOAD, was used for measuring the side wall strength. A load was applied at a constant speed from above the central portion 31 m of the flat surface portion 31 and the central portion 231 m of the flat surface portion 231, and the load at the stage of displacement of 5 mm was defined as the side wall strength. For the determination of the side wall strength, a threshold value of 40 N or more or less than 40 N was set. Table 1 shows the results of evaluation of the side wall strength of each filler, and is indicated by ◯: side wall strength, and ×: side wall strength insufficient.

(Monitoring survey)
Each of the fillers of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 was prepared, and a flat surface portion 31 of the upper square cylinder portion 50 was provided on a monitor of 100 people in their 20s to 70s. , And the flat part 231 of the upper square cylinder part 250, and then the contents were poured out. At that time, those that did not collapse were counted as one point. Table 1 shows the total score.

(Comprehensive evaluation)
Comprehensive evaluation of each PET bottle (each filler) of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 based on the above-mentioned lightness, side wall strength test, and monitoring survey. It has been made. Table 1 shows the results of the comprehensive evaluation. The overall evaluation is indicated by ○: good, ×: no aptitude.

The following points were derived from the above-mentioned examples. The PET bottle 1 (filler) according to Example 1 was configured to have light weight, and was hard to be crushed while having sufficient side wall strength. And many monitors supported its ease of holding.

On the other hand, in Comparative Example 1, although the weight was reduced and the side wall strength was sufficient, crushing occurred. In Comparative Example 2, although the crush resistance was improved, it was not sufficient and it was not lightweight. In Comparative Example 3, although the weight was reduced, the side wall strength was insufficient, so that irreversible bending did not occur, but crushing occurred during pouring, and the ease of holding was insufficient. Then, when the weight reduction was slightly insufficient as in Comparative Example 4, the side wall strength and the crush resistance were satisfied.

From the results of the above examples, the PET bottle 1 and the filler according to the present embodiment have sufficient side wall strength, that is, rigidity, are less likely to be crushed, and are easy to hold even if the weight is reduced. It was shown to be. Therefore, in the present embodiment, it has been shown that it is possible to provide a square PET bottle 1 which has rigidity, is hard to be crushed, is lightweight, and is excellent in ease of holding.

The present disclosure can be suitably used for various plastic bottles filled with a liquid as a content. However, the present disclosure is not limited to the embodiments and examples described above. The plastic bottles of the present disclosure include, for example, various non-carbonated beverages such as water, green tea, oolong tea, black tea, coffee, fruit juice, soft drinks, seasonings such as soy sauce, sauce, and mirin, foods containing cooking oil, and alcoholic beverages. Useful for containing detergents, shampoos, cosmetics, medicines and any other content. In particular, the plastic bottle of the present disclosure is suitable for use in a large bottle whose weight increases due to a large amount of contents because the container is easy to hold. Further, since the plastic bottle of the present disclosure is excellent in operability of the container when pouring out the contents, it is also suitable for applications such as transferring from a large bottle to a container for subdivision.

1 PET bottle (plastic bottle)
10 Mouth 20 Shoulder 30 Body 31 Flat surface 31m Central 31p Peripheral 32 Corner 40 Bottom 50 Upper square tube (square tube)
51 Circumferential groove (groove)
51b Wide part 51n Narrow part Dc Corner part depth Dm Central part depth Dp Peripheral part depth Wc Corner part width Wm Central part width Wp Peripheral part width

Claims (6)

A plastic having a mouth part, a shoulder part, a body part, and a bottom part sequentially in the axial direction, and the body part having a square cylinder part consisting of a plurality of flat parts and a corner part connecting the flat parts adjacent to each other in the circumferential direction. In the bottle
The square tube portion has a groove that goes around the plastic bottle.
The flat surface portion has a central portion and a peripheral portion, and has a central portion and a peripheral portion.
The width of the groove is such that the peripheral portion is wider than the central portion and the central portion is wider than the corner portion.
The depth of the groove is a plastic bottle characterized in that the peripheral portion is deeper than the central portion. The plastic bottle according to claim 1, wherein the groove has a value of the ratio of the depth at the central portion to the depth at the peripheral portion of 0.45 or more and 0.95 or less. The plastic bottle according to any one of claims 1 to 2 , wherein the groove has a curved shape in a cross section in the axial direction. The plastic bottle according to any one of claims 1 to 3 , wherein the internal volume of the plastic bottle is 680 ml or more and 2500 ml or less. The plastic bottle according to any one of claims 1 to 4 , wherein the value of the ratio of the mass to the volume of the plastic bottle is 0.0105 g / ml or more and 0.0300 g / ml or less. The plastic bottle according to any one of claims 1 to 5 and
A filler characterized by being composed of a liquid to be filled.

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