JP2007302268A - Plastic bottle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To give a plastic bottle a structure with the enhanced rigidity of a contact point without increasing the thickness of the wall surface of the bottle to prevent the deformation of the bottle under line pressure. <P>SOLUTION: The plastic bottle 1 having a trunk with a circular cross-sectional shape is provided with an annular bulging portion CP (6) that is formed as a maximum diameter portion by bulging a proper part of the trunk toward the outer periphery. The annular bulging portion CP (6) is formed into a polygonal shape having curved recessed surfaces recessed toward the center of the bottle 1, which recessed surfaces are formed by alternately arranging long side recessed surface portions 7 circumferentially long and short side recessed surface portions 8 circumferentially short along the whole periphery in succession. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bottle-shaped plastic bottle (hereinafter abbreviated as a bottle) formed by stretch blow molding a synthetic resin such as polyethylene terephthalate, which is used as a packaging container for various liquids such as beverages, liquid seasonings, and alcoholic beverages. .

  In the process of filling and packaging the liquid into the bottles, a large number of bottles are concentrated on the transport conveyor in the bottle transport line before and after filling, and the bottles are transported while pressing each other. For this reason, the bottle is subjected to lateral pressure (line pressure) through the contact between the bottles and the contact with the line guides on both sides of the conveyor during transportation, causing the bottle wall to be crushed and deformed, thereby reducing the appearance quality of the bottle. Sometimes. In particular, as shown in FIG. 6, a bottle with a handle having a large liquid filling capacity and a capacity of 1.8 liters is likely to be deformed due to an increase in line pressure applied to the bottle.

  In order to prevent such deformation of the bottle on the conveyance line, conventionally, the wall thickness of the maximum outer diameter portion (contact point) of the bottle body portion where the adjacent bottle is in contact with the adjacent bottle while sliding on the conveyance belt is applied. The rigidity of the portion where the bottle is molded by increasing the thickness or by forming a concave or convex rib R on the wall surface along the contact point CP as shown in FIG. Is locally increased so that crushing deformation hardly occurs (see, for example, Patent Document 1).

Japanese Patent No. 2545037

However, if the entire bottle is made thin like the former and the contact point is made thicker than the other parts, the strength against line pressure will increase, but the parts other than the contact points will be relatively thin. Other physical properties of the bottle such as reduced pressure strength and buckling strength are reduced. If the entire wall surface of the bottle including the contact point is made thick, the weight of the bottle increases and the molding cost increases.
Further, if the ribs are simply provided along the contact points as in the latter case, sufficient rigidity against the line pressure cannot be obtained. In addition, depending on the size and shape of the contact point, the thickness of the rib and the surrounding wall surface portion may be uneven, and the moldability (mold fidelity) of the bottle may be impaired and molding may be difficult.

  In view of such a problem of the prior art, the present invention aims to increase the rigidity of the contact point without increasing the wall thickness of the bottle and to prevent the bottle from being deformed by receiving line pressure. To do.

  In order to solve the above problems, the present invention, in a bottle having a circular cross-sectional body portion, to form an annular bulging portion that bulges a suitable portion of the bottle body portion to the outer peripheral side and becomes the maximum outer diameter portion, This annular bulging portion is a curved concave surface that is recessed toward the center of the bottle, and is provided in a polygonal shape in which long side concave portions and long short side concave portions that are long in the circumferential direction are alternately connected over the entire circumference. It is characterized by that.

  In the bottle having the above-described configuration, the annular bulging portion is formed so that the longitudinal section thereof has a substantially trapezoidal shape, and the upper and lower slopes of the concave portion in the central longitudinal section of the long-side concave portion provided in the annular bulging portion. The crossing angle (A) formed by the wall surfaces is set and formed to be smaller (A <B) than the crossing angle (B) formed by the upper and lower inclined wall surfaces of the concave surface portion in the central longitudinal section of the short side concave surface portion. Is preferred.

The bottle of the present invention has a long side concave surface portion and a short side concave surface portion alternately arranged along the circumferential direction only in the contact point portion which is the maximum outer diameter portion in the body portion of the bottle having a circular cross section. The cross section becomes a polygonal shape. Both concave portions are curved concave surfaces and are recessed toward the inside of the bottle, and both ends intersecting with the adjacent concave surface portions are corner portions protruding outward from the bottle, and the corner portions themselves function as reinforcement, and in addition to this corner portion Since the curved concave surface that is continuous in the circumferential direction across the surface functions as a reinforcement similar to the concave rib, the mechanical strength of the contact point is increased, and the rigidity of the contact point can be increased without increasing the thickness.
In addition, by forming the annular bulging portion serving as a contact point in a substantially trapezoidal longitudinal section, stretching at the time of blow molding can be performed smoothly, and the contact point can be formed with a uniform thickness over the entire circumference of the contact point. . Then, by forming the long side concave surface portion and the short side concave surface portion in the annular bulging portion, corner portions are formed at the boundary between the respective concave surface portions and the upper and lower inclined wall surfaces, and this serves as a reinforcement against the crushing deformation. In order to function, the mechanical strength of the contact point is further increased. At this time, the intersection angle formed by the upper and lower inclined wall surfaces of the concave surface portion in the central longitudinal section of the long side concave surface portion is smaller than the intersection angle formed by the upper and lower inclined wall surfaces of the concave surface portion in the central vertical section of the short side concave surface portion. By setting, it is possible to effectively prevent the occurrence of crushing deformation even for a large-capacity bottle such as a bottle with a handle having a capacity of 1.8 liters.

  According to the bottle of the present invention, since the wall surface of the contact point is arranged in a polygonal shape in cross section by alternately arranging the long side concave surface portion and the short side concave surface portion, the rigidity of the contact point is increased, and the bottle is being conveyed. The strength against line pressure can be improved, and the bottle can be made into a structure that is less likely to be crushed and deformed.

A preferred embodiment of the present invention will be described with reference to the drawings.
1 and 2 are external views of a side surface and an upper surface of a bottle according to an embodiment of the present invention, FIG. 3 is a cross-sectional enlarged end view of a contact point of the bottle of FIG. 1, and FIG. It is a center longitudinal cross-section enlarged end view of a short side concave part.

  In the illustrated embodiment, the present invention is applied to a bottle with a handle having a capacity of 1.8 liters formed by blow molding a parison made of polyethylene terephthalate. The bottle 1 has a body 3 that rises from a circular bottom 2 into a hollow cylindrical shape, and the upper half of the body 3 has a gently tapered shape. A cap (not shown) is attached to the tip of the bottle 1. A portion 4 is provided, and a handle 5 is integrally attached to a side surface of the upper half of the body portion, and an annular bulging portion 6 that is a maximum outer diameter portion of the bottle 1 is formed at two locations of a lower portion and an intermediate portion of the bottle 1. The annular bulging portion 6 is formed as a contact point CP in a polygonal cross-sectional shape.

More specifically, the upper and lower contact points CP of the bottle 1 are formed by an annular bulging portion 6 bulging from the bottle body portion toward the outer periphery, and the circumferential flank length of the annular bulging portion 6 is long. The long side concave surface part 7 having a long side and the short side concave surface part 8 having a short side length are provided in a shape in which the bottles are alternately connected over the entire circumference in the circumferential direction.
As shown in FIG. 3, the long-side concave surface portion 7 and the short-side concave surface portion 8 are substantially rectangular curved concave surfaces that are recessed toward the center of the bottle 1 along an arc around a vertical axis having predetermined curvature radii R1 and R2. The both side ends where the adjacent concave surface portions 7 and 8 cross each other are formed to be corner portions, and each corner portion is located on the circumference of the maximum outer diameter circle C over the entire circumference of the bottle. Yes. The curved concave surfaces of the concave surface portions 7 and 8 can be curved concave surfaces that are recessed toward the center of the bottle 1 with a predetermined radius of curvature in the vertical direction as shown in FIG. It is good also as a flat surface as shown with a middle broken line.

In this embodiment, the length of the side of the short side concave surface portion 8 is set to about 1/4 of the length of the side of the long side concave surface portion 7, and the center of each concave surface portion adjacent to the center O of the bottle 1. 12 are arranged alternately along the maximum outer diameter circle C so that the crossing angle α of the line segment connecting each other is 15 °, and each corner is the circumference of the maximum outer diameter circle C. Arranged above, the peripheral wall cross section of the contact point CP is provided in a 24 square shape inscribed in the maximum outer diameter circle C.
The radius of curvature R1 of the curved concave surface forming the long side concave surface portion 7 can be appropriately set within a range of 1 to 5 times the maximum outer diameter φ of the bottle 1, but it is the maximum outside due to the required strength of the bottle and the appearance shape. It is preferable to set to about 3 times the diameter.
Further, the radius of curvature R2 of the curved concave surface forming the short side concave portion 8 can be set as appropriate within a range of 3 to 10 times the circumferential length (short side width) 8W, but the required strength and appearance of the bottle. It is preferable to set the width to about 5 times the short side width 8W in consideration of the shape.

The long side concave surface portion 7 and the short side concave surface portion 8 are shaped so as to be connected to the upper and lower inclined wall surfaces at predetermined angles, respectively. That is, the annular bulging portion 6 forming the contact point CP is formed in a substantially trapezoidal shape in vertical section, and thereby inclined wall surfaces 7a, 7b and 8a, 8b are formed above and below the both concave surface portions 7, 8. .
The upper inclined wall surface 8a in the central longitudinal section of the short side concave surface portion 8 is provided with a slightly recessed recess, thereby reinforcing the deformation against crushing. As a result, as shown in FIG. 4, the crossing angle formed by the upper inclined wall surface 7a and the lower inclined wall surface 7b of the concave surface portion in the central longitudinal section of the long side concave surface portion 7 is A (FIG. 4A). When the crossing angle formed by the upper inclined wall surface 8a and the lower inclined wall surface 8b of the concave surface portion in the central longitudinal section of the short side concave surface portion 8 is B (FIG. 5B), the cross angle A of the long side concave surface portion 7 Is set to be smaller (A <B) than the intersection angle B of the short side concave surface portion 8.

  In this embodiment, the inclination angle β between the downward inclined wall surfaces 7b, 8b and the vertical wall of the bottle body in the long side concave surface portion 7 and the short side concave surface portion 8 is set to a constant 43 °, and the long side concave surface portion 7 The inclination angle A1 between the upper inclined wall surface 7a and the vertical wall of the bottle body in the central vertical section of the bottle is 60 °, and the inclination angle between the upper inclined wall surface 8a and the vertical side wall of the bottle body in the central vertical section of the short side concave surface 8 B1 is set to 35 °. As a result, the crossing angle A is set to 73 ° and the crossing angle B is set to 98 °, and A <B.

  Thus, the bottle 1 of this embodiment in which the long-side concave surface portion 7 and the short-side concave surface portion 8 are alternately connected to the annular bulging portion 6 serving as the contact point CP has a uniform wall thickness on the entire wall surface of the bottle body. In addition, the rigidity of the contact point CP becomes extremely high. This was confirmed by the examples described below.

A plurality of bottles 1 having the above-described configuration were formed with different wall thicknesses, and the strength against line pressure was measured for each.
The molding dimensions of each part of the bottle 1 are as follows: the outer diameter of the bottom 2 is 106 mm, the height from the bottom 2 to the mouth 4 of the bottle 1 is 300 mm, the maximum outer diameter φ of the bottle shown in FIG. Concave surface 7 has a horizontal width of 23 mm, a height of 12.5 mm, and short side concave surface 8 has a horizontal width of 5.7 mm and a height of about 4.7 mm, and the corners on both sides of both concave surfaces are maximum. It was formed so as to be positioned on the circumference of the outer diameter circle C. The curvature radius R1 of the curved concave surface forming the long side concave surface portion 7 is 300 mm, the curvature radius R2 of the curved concave surface forming the short side concave surface portion 8 is 25 mm, the crossing angle A is set to 73 °, and the crossing angle B is set to 98 °. did.

  Measurement of strength against line pressure was performed as follows. That is, three bottles 1 of the same specification are prepared, each filled with 1.8 liters of water, and these are vertically arranged in a row between a support plate and a pressing plate that are vertically arranged opposite to each other. At this time, contact points CP of adjacent bottles are kept in contact with each other. Then, the pressing plate is pressed in the direction of the supporting plate in a state where the supporting plate and the pressing plate are in contact with the side surfaces of the bottles 1 and 1 at both ends arranged in a row, and the wall surface (contact of the bottle 1 in the center portion) The pressing force of the pressing plate when the deformation occurred at the point CP) was measured, and this was taken as the measured line pressure resistance strength of the bottle 1.

  For the bottle 1 of this embodiment, seven types of bottles having a wall thickness of 0.27 mm, 0.278 mm, 0.281 mm, 0.296 mm, 0.31 mm, 0.32 mm, and 0.321 mm, respectively, are molded. The strength was measured as described above. The result is shown in FIG. The wall thickness of the bottle 1 is measured at the central portion of the long side concave portion 7 of the contact point CP.

As a comparative example, a conventional bottle having the same capacity, in which the contact point CP shown in FIG. 6A is provided with a concave rib R, and the contact point CP shown in FIG. The bottles not subjected to the above were also molded with varying wall thicknesses, and the same strength measurement as described above was performed. The thickness was measured by cutting the central portion of the contact point CP.
The bottles of FIG. 6 (A) were subjected to strength measurement for five types having wall thicknesses of 0.264 mm, 0.278 mm, 0.283 mm, 0.303 mm, and 0.335 mm, respectively. The result is shown as Comparative Example 1 in FIG.
Moreover, the bottle of FIG. 6 (B) has a thickness of 0.311 mm, 0.328 mm, 0.346 mm, 0.355 mm, 0.356 mm, 0.376 mm, 0.378 mm, 0.379 mm, 0.382 mm, respectively. , 0.407 mm, 0.42 mm, and 0.436 mm were measured for strength. The result is shown as Comparative Example 2 in FIG.

  As is apparent from the measurement results, the bottle 1 of the present embodiment has a very high strength against the line pressure as compared with the conventional bottle, and the contact point CP is highly rigid, so that deformation on the transport line is difficult to occur. It was confirmed.

  In the illustrated embodiment, the two contact points CP of the lower part and the middle part of the bottle 1 are provided in a polygonal shape in which the long side concave surface part 7 and the short side concave surface part 8 are alternately arranged. Only the contact point CP at the lower part of the bottle 1 that is likely to cause the occurrence of the problem may be provided in a polygonal shape. Further, the contact point CP can be provided in an arbitrary polygonal shape by arranging an appropriate number of the long-side concave surface portions 7 and the short-side concave surface portions 8 according to the capacity of the bottle 1 and the required strength. It is.

It is a side appearance figure of a bottle of one embodiment of the present invention. It is an upper surface external view of the bottle of FIG. It is a cross-sectional enlarged end view of the contact point of the bottle of FIG. (A) and (B) are the center longitudinal expansion enlarged end views of the long side concave surface part and short side concave surface part of the bottle of FIG. 1, respectively. It is the graph which showed the measurement result of the intensity | strength with respect to the line pressure of the bottle of FIG. 1 and the conventional bottle. (A), (B) is a side external view of the conventional bottle with a handle, respectively.

Explanation of symbols

1 bottle, 2 bottom part, 3 body part, 4 mouth part, 5 handle, 6 annular bulge part, 7 long side concave part, 8 short side concave part, 7a, 8a upper inclined wall surface, 7b, 8b lower inclined wall surface, CP Contact point

Claims (2)

In a plastic bottle having a circular cross-section body,
An appropriate portion of the bottle body is bulged to the outer peripheral side to form an annular bulging portion that becomes the maximum outer diameter portion, and the annular bulging portion is a curved concave surface that is recessed toward the center of the bottle. A plastic bottle characterized in that a long-side concave surface portion having a long length and a short short-side concave surface portion are provided in a polygonal shape that is alternately connected over the entire circumference. The annular bulging portion is formed so that its longitudinal section is substantially trapezoidal, and the crossing angle formed by the upper and lower inclined wall surfaces of the concave surface portion in the central longitudinal section of the long side concave surface portion provided in the annular bulging portion ( A) is formed so as to be smaller (A <B) than an intersection angle (B) formed by upper and lower inclined wall surfaces of the concave surface portion in the central longitudinal section of the short side concave surface portion. The described plastic bottle.

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