JP3772230B2 - Synthetic resin square hollow container - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a cylindrical hollow container formed by biaxially stretching blow molding a thermoplastic synthetic resin, and in particular, the container is filled with the contents by high-temperature heat sterilization or filled with the contents. The present invention relates to a polygonal hollow container suitable for heat sterilization.
[0002]
[Prior art]
In recent years, as containers for filling contents that require high-temperature heat sterilization, such as juices such as juices, soft drinks, and other beverages, a wide range of hollow containers made of polyethylene terephthalate (PET) resin are formed by biaxial stretch blow molding. It is used a lot.
However, in the above-mentioned PET container, internal residual stress is generated during molding in the normal biaxial stretch blow molding method, and heat deformation is likely to occur during high temperature heating filling and high temperature heating sterilization. A step of performing heat setting is provided to prevent deformation of the container due to heat and residual stress.
In addition, when performing high temperature heating and filling as described above, the inside of the container cooled after filling is in a reduced pressure state, and when performing high temperature heat sterilization, the inside of the container is temporarily pressurized and pressure is applied to the container wall. The container is deformed.
Therefore, as a means for preventing such deformation of the container, generally, a deformable wall that surrounds a reinforcing rib formed with band-shaped irregularities on the side wall surface of the container or absorbs and relaxes changes in internal pressure. A portion (panel wall) is provided so that the other part of the side wall is not deformed and the appearance of the container is not impaired.
[0003]
Examples of the known structure having the above structure include the following.
In a hollow container with a roughly prismatic outer shape, ribs that bulge the middle wall of the container in a band shape and circumferential grooves that are dented are alternately placed to give rigidity to the side wall. In the case of forming a lateral reinforcing rib part provided on the inner wall and an internal pressure change absorbing wall (panel wall) part in which the upper and lower wall surfaces sandwiching the reinforcing rib part are expanded outwardly, 58-161817.
In addition, a panel is formed by forming two substantially rectangular recesses on the wide front wall and rear wall of the body of the hollow container having a rectangular cross section, and two approximately rectangular recesses on the narrow side wall. A wall is formed, and a reinforcing protrusion and a groove are provided on the outer periphery of the square recess of the wide wall surface, and a reinforcing protrusion is provided laterally in the center of the bottom wall of the upper recess. What is provided is described in Japanese Utility Model Laid-Open No. 64-4662.
[0004]
Similarly, in an octagonal column-shaped hollow container with a square section cut off a little, a panel wall is provided above and below the reinforcing ribs of the groove around the wall surface in the middle of the trunk, and the groove Japanese Utility Model Laid-Open No. 1-116128 discloses that the depth is formed so as to increase from the corner portion to the center portion so as to uniformly increase the strength of the entire peripheral wall of the container.
Furthermore, in a casing in which a rib is formed in a circumferential groove shape in a substantially middle portion (waist portion) of a barrel portion of a cylindrical rectangular container whose corners are rectangular, the depth of the rib in the panel wall portion is determined. It is formed deeper than in the corner, and the rib in the panel wall is formed in a step shape from the rib in the corner toward the inside of the housing to increase the rigidity of the container wall and reduce the wall thickness. What is made possible is described in Japanese Utility Model Laid-Open No. 5-94112.
[0005]
However, the common point of such a conventional cylindrical rectangular container is that, as shown in FIGS. 7 and 8, the concave groove of the reinforcing rib 7 formed in the intermediate waist part of the container body is not a side wall but a corner. A concave groove is also formed as a reinforcing rib 7a on the surface of the square wall 6, and a structure in which a homogeneous and integral concave groove continuous with the concave groove on the side wall surface is provided.
As a general rule, a container having such a structure is resistant to the force applied to the side wall surface from the lateral direction and has a certain level of strength, but the corner wall 6 has an arrow on the surface. As shown in FIG. 9, the cross section of the container waist part is easily deformed into a rhombus, and a strong vertical force is applied to the container. However, there is a drawback that buckling deformation is likely to occur in the recessed groove portion of the reinforcing rib 7 formed in the waist portion.
[0006]
[Problems to be Solved by the Invention]
Various types of hollow containers are used, but generally, a cylindrical bowl-shaped container having a circular or quadrangular cross section is commonly used. Since the body wall surface is at an equal distance from the central axis in any part, the wall surface is easily stretched uniformly during blow molding, and as a result, the shape and strength of the container are stable.
However, in the case of a quadrangular or polygonal shape, the wall surface of the body portion is different in distance from the central axis, so that it is difficult to stretch the entire wall surface uniformly during blow molding. The amount of stretching differs depending on the position, and the internal residual stress also varies depending on the location, so it becomes a cause of deformation of the container even after heat-set processing to produce a product, and it becomes an unstable factor of the shape and strength of the container. ing.
[0007]
However, recently, in order to differentiate the product, a hollow container made of a synthetic resin having a substantially quadrangular columnar or octagonal columnar shape with an emphasis on the viewpoint of the design of the container has been used. In order to respond to such demands, the container wall surface is provided with a design-excellent appearance, a wall portion that absorbs a pressure change in the container caused by a heat change, and a reinforcing wall part that can withstand external force. It aims at providing the polygonal hollow container with which it prepared for.
However, a polygonal columnar hollow container as described in Japanese Utility Model Laid-Open No. 1-161428 and Japanese Utility Model Laid-Open No. 5-94112 has a certain pressure resistance against an external force acting on the side wall of the container from the front. Although it has strength, it is weak against external force acting in the direction perpendicular to the vertical axis on the wall surface of the corner, easily deformed into a rhombus, and particularly against strong force applied to the groove-like rib surface of the corner Is deformed with a beeping sound, and during transportation in a state where containers are stacked, it is easy to cause buckling deformation at the rib portion around the trunk for other vertical compression loads. It was necessary to eliminate this drawback.
[0008]
[Means for Solving the Problems]
The present invention basically relates to a hollow container having an octagonal shape by cutting a cylindrical corner portion having a rectangular cross section into a flat surface narrower than a side surface portion. In order to absorb the change in pressure, a wall portion surrounded by a concave groove is formed in a rectangular shape on the flat side wall portion of the container, and both ends do not reach the concave groove in the longitudinal direction substantially at the center of the wall portion. A ship bottom-shaped bottom line is formed to a certain extent, and is deformed with respect to pressure that forms a pair of inclined ridge lines extending in a V shape from the end of the bottom line and reaching the corners of the rectangular groove A panel wall with a possible recess is provided.
Further, in order to obtain a container structure capable of withstanding external force, each of the ribs of the reinforcing rib provided in the lateral direction in the central portion (waist portion) of the side wall of the container is not formed on the flat surface of the corner portion. It becomes a reinforcing rib independent of the wall surface, and the flat surface of the corner portion prevents deformation of the side wall portion due to diagonal and longitudinal external forces.
Furthermore, the bottom part of the container that is most susceptible to impacts is formed with a convex curved surface with a large curvature at the ground contact part near the outer periphery, and the central part is formed in an inversion curve inwardly with a multi-stage curvature to give strength. Shall be.
[0009]
The invention of the present application will be described below based on one embodiment with reference to the drawings. FIG. 1 and FIG. 2 show a rectangular columnar hollow container obtained by biaxial stretching blow molding of the polyethylene terephthalate (PET) resin of the present invention, and more specifically, a casing having a substantially octagonal cross section of a container body wall. .
As shown in FIGS. 3 to 5, the basic shape of the body portion of the casing 1 is a quadratic columnar shape composed of main walls including front and rear walls 2, 3 and left and right side walls 4, 5. As shown in FIGS. A flat corner wall 6 that is rounded off is formed, and a reinforcing rib 7 having a groove shape is provided around the middle portion of the body side wall.
As shown in FIGS. 1 and 2, the reinforcing rib 7 is formed by forming a concave groove in a straight line in the lateral direction at the waist of the side wall, as can be seen from FIGS. The concave groove is formed so as to gradually become deeper from the central portion of the body wall, and both end portions thereof are inclined toward the corner portion and become shallow and disappear on the flat surface of the corner portion 6. Yes.
In other words, the reinforcing rib 7 is provided around the container side wall so that the concave groove is interrupted and discontinuous at the corner portion 6, so that the flat surface of the corner portion is formed of the reinforcing rib. It is formed in a vertically continuous surface without being interrupted by the groove portion, the upper end portion of the flat corner surface is converged to the root of the mouth and neck portion 15 through the direction portion 12, and the lower end is a curved surface of the bottom portion 13. Has reached.
[0010]
Each of the side walls of the body is provided with panel walls 10 for absorbing changes in internal pressure at positions above and below the reinforcing ribs 7 at the waist. A pair of slopes that are formed by surrounding a flat portion in a rectangular shape with a groove 9 and reaching the corner of the rectangular groove 9 in a V shape from both ends of the bottom bottom line 8 formed at the center of the rectangle. The ridgeline 8a is formed on a recessed wall capable of pressure deformation.
Further, on the side wall of the container, the upper and lower positions of the panel wall 8 sandwiching the reinforcing rib 7 formed on the waist, that is, the side wall near the shoulder 12 and the bottom 13 of the container, A rib 11 having a length equivalent to the lateral direction of the rectangular side is formed in a single character and reinforced.
The bottom part of the rectangular container is the part that is most difficult to receive a uniform stretching action when blow molding, that is, the stretch amount is small and the strength tends to be small, but the bottom part receives the impact force most, The bottom wall 13 is formed with a curved surface 14 with a large curvature at the ground contact portion near the outer periphery and a wall 14 that is inverted and curved inward by changing the curvature in a multistage shape near the center.
[0011]
As described above, according to the present invention, in the hollow columnar container having an octagonal cross section, the concave groove of the reinforcing rib 7 provided in the waist portion of the side wall has a corner as shown in FIGS. Since it is not formed on the flat surface of the corner 6 and flattened without a step, it becomes stronger against the diagonal force acting to deform the container into a rhombus on the flat surface of the corner 6, It also becomes strong against the compressive force from the up and down direction of the container, and becomes difficult to buckle.
In addition, the eight corners of the corner are the deepest waist step, and the valley of the corner is a curved surface. The label can be fixed smoothly and reliably up to the portion.
Furthermore, since the waist valley portion of the large flat portion of the four main side surfaces of the container has a large curved shape that smoothly contacts the corner surface, the shape of the container can be improved and the strength can be improved. It was.
In the present invention, it is needless to say that the basic shape is not limited to a square or a square, and may be a pentagon, a hexagon, or another polygon.
[0012]
【The invention's effect】
The invention of the present application is a concave groove-shaped reinforcing rib provided around the waist portion of the middle portion of the barrel side wall of a polygonal hollow container in which a flat wall is formed at a corner portion where the four corners have a square cross section. 7 is formed on the side wall in a straight line, and the concave groove is formed deep at the center, shallow at both ends, and disappears on the flat surface of the corner 6. The flat surface of the corner is formed as a continuous surface in the vertical direction without being interrupted by the groove portion of the reinforcing rib at the waist, so that a strong diagonal force is applied to the flat corner surface. However, it is possible to obtain a casing that is not easily deformed into a rhombus shape and that has a strong resistance against the compressive force in the vertical direction on the container.
[Brief description of the drawings]
FIG. 1 is an overall front view of the present invention.
FIG. 2 is an overall side view showing a corner face of the present invention shifted by 45 degrees from the front.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
4 is a cross-sectional view taken along the line CC in FIG. 1. FIG.
5 is a cross-sectional view taken along the line BB in FIG.
FIG. 6 is a bottom view of the container of the present invention.
FIG. 7 is an overall side view showing a corner face of a conventional container shifted by 45 degrees from the front.
8 is a cross-sectional view taken along line B′-B ′ in FIG.
FIG. 9 is a B′-B ′ cross-sectional view of a conventional container deformed by receiving an external force on a corner surface.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Container body 2 Front side wall 3 Rear side wall 4 Left side wall 5 Right side wall 6 Corner wall 7 Groove-shaped reinforcing rib 8 Panel wall bottom ridge line 9 Panel wall concave groove 10 Panel wall 11 Reinforcing rib 12 Container shoulder 13 Container bottom 14 Container bottom Concave wall 15 Container neck

Claims (3)

A polygonal shape in which a reinforcing rib having a groove shape is provided in the middle part of the barrel side wall of a substantially octagonal cylindrical container that is formed by rounding the four corners of the rectangular shape of the cylindrical container to form a flat corner wall. In the synthetic resin container, the concave groove of the reinforcing rib formed laterally in the waist portion of the side wall is formed gradually deeper from the central portion of the side wall, and both end portions thereof become inclined surfaces and corner angles. A rectangular hollow container made of synthetic resin, formed so as to disappear in contact with a flat surface of a portion. The flat surface of the corner portion formed by chamfering the four corners of the rectangular shape of the cylindrical container is connected to the end portion of the reinforcing rib provided in the lateral direction on the waist portion of the side wall, and continuous in the vertical direction. 2. The square hollow container made of synthetic resin according to claim 1, which is formed in a flat surface and is formed so that the upper end of the flat surface is converged to the root of the mouth and neck through the shoulder of the container. . A ship bottom-like internal pressure absorbing panel is formed in a rectangular shape on each side wall of the upper and lower parts sandwiching reinforcing ribs provided around the middle waist of the barrel side wall of the polygonal cylindrical container. A rectangular hollow container made of synthetic resin according to claim 1.

Images