JP2011251711A - Synthetic-resin-made container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synthetic-resin-made container capable of increasing a buckling strength against a load in an axial direction without sacrificing other properties.SOLUTION: The synthetic-resin-made container 1 includes a mouth 2, a body 4 connected to the mouth 2 via a shoulder 3, and a bottom 5 blocking a lower end of the body 4. The body 4 is composed of an upper side body 8 and a lower side body 9 bisected by a horizontal line at a waist 7, and a plurality of horizontal grooves 10 extending throughout a circumference are provided on the upper side body 8 with intervals above and below. The horizontal groove 10 has a groove bottom wall 10a with a cross section formed in a single arc protruding toward a container inward side, and a pair of groove side walls 10b respectively connected from both ends of the groove bottom wall 10a to side walls of the upper side body 8 and each having a cross section formed in a single arc protruding toward a container outward side. In the horizontal groove 10, a depth d is within a range of 1.5-2.0 mm, and a ratio R/Rof a curvature radius Rof the groove side wall 10b to a curvature radius Rof the groove bottom wall 10a is within a range of 2-3.

Description

  The present invention relates to a synthetic resin container having a mouth portion, a shoulder portion, a trunk portion, and a bottom portion, and particularly relates to a container that balances buckling strength and other performances.

  Synthetic resin containers such as PET bottles are light weight, easy to handle, excellent in storage stability of contents, and low in cost. It is often used as a container for filling cosmetics or drugs.

  A synthetic resin container, particularly a container designed to reduce the amount of resin, has a relatively low strength against external force.For example, when the container body is gripped when the contents are poured out, the container is deformed and the contents are deformed. Problems such as popping out objects occur. Therefore, for example, as described in Patent Documents 1 and 2, in a container in which a mouth portion, a shoulder portion, a body portion, and a bottom portion are integrally formed of a synthetic resin, the body portion is recessed inward in the radial direction. In addition, by arranging a plurality of transverse grooves extending along the entire circumference at predetermined intervals in the axial direction, the strength (rigidity) in the radial direction is increased, and deformation of the body portion against external force such as gripping force is suppressed. I am doing so.

Japanese Utility Model Publication No. 56-14173 Japanese Patent Publication No. 7-102856

  By the way, in such a container made of a synthetic resin, it is necessary to ensure the buckling strength in the axial direction so that it can withstand the load when an axial load is applied to the container during transportation or the like. However, there is a problem that it is easy to buckle with the lateral groove as a starting point simply by providing the lateral groove as described above. On the other hand, as a result of repeated research by the inventors, by improving the cross-sectional shape of the lateral groove, the lateral groove is stretched and deformed to some extent when an axial load is applied. It was found that it was possible to avoid the loss of the buckling strength of the container.

  However, in order to increase the buckling strength by forming such a transverse groove that is deformed and stretched, it is conceivable to increase the amount of expansion and deformation of the entire transverse groove by providing a large number of transverse grooves over the entire axial length of the body portion. The required performance of the container is not only the radial strength and buckling strength, but especially for containers with heat resistance suitable for filling hot contents, the containers after filling and sealing the contents In order to prevent an irregular shape change of the container due to a decrease in the internal pressure inside, a panel that exhibits reduced pressure absorption performance (a reduced pressure absorption panel) must be disposed in the body (see Patent Documents 1 and 2). Thus, the place where the lateral groove can be disposed is limited in view of other performance, and there is a limit to increase the buckling strength by increasing the number of lateral grooves.

  Therefore, according to the present invention, in a container made of a synthetic resin having a lateral groove in the body portion of the container, the axial load can be obtained without sacrificing other performance, that is, without increasing the number of lateral grooves disposed in the body portion. It is an object of the present invention to provide a synthetic resin container capable of increasing the buckling strength against.

The present invention has been made to solve the above-mentioned problems, and a synthetic resin container according to the present invention includes a mouth portion that forms an opening that allows the contents to be taken in and out, and a shoulder portion in the mouth portion. And a bottom part that closes the lower end of the body part, and the body part is composed of an upper body part and a lower body part that are divided into two vertically with a waist as a boundary. In the synthetic resin container provided with a plurality of lateral grooves extending around the circumference with a space in the vertical direction, the lateral groove includes a groove bottom wall formed by a single arc projecting inward of the container, and the groove bottom wall And a pair of groove sidewalls each formed by a single circular arc that protrudes outward from the container and is connected to the sidewalls of the upper body portion from both ends of the lateral groove, and the lateral groove has a depth of 1.5 mm. ˜2.0 mm and the curvature radius R _S of the groove sidewall is The ratio R _S / R _B to the radius of curvature R _B of the groove bottom wall is in the range of 2 to 3.

In such a synthetic resin container, the groove bottom wall and the groove side wall of the lateral groove are formed by a single arc projecting in opposite directions, and the radius of curvature of the groove bottom wall is equal to the radius of curvature _RS of the groove side wall. the ratio R _{S /} R _B for R _B since it was 2-3, while constituting easily deflected the groove bottom wall with respect to the axial direction of the load, it is possible to act to restore the deflection groove sidewalls That is, when an axial load is applied to the container, the lateral groove is greatly expanded and contracted by deformation of the groove bottom wall, while the groove bottom wall can be restored and supported from both sides by the groove side wall. It is possible to significantly increase the buckling strength by improving the cushioning property.

  Therefore, according to the synthetic resin container of the present invention, the buckling strength can be increased by providing a lateral groove that can be greatly expanded and contracted in a part of the body part, that is, the upper body part. In other areas of the unit, means for exhibiting other performance such as reduced pressure absorption performance can be arranged, and the buckling strength against axial load can be increased without sacrificing other performance It becomes.

Incidentally, in the synthetic resin container of the present invention, the radius of curvature R _B of the groove bottom wall is preferably set to 1.0 mm.

  Furthermore, in the synthetic resin container according to the present invention, the vertical length between the boundaries between the pair of groove side walls and the upper body side wall in the lateral groove is in the range of 5.2 mm to 6.93 mm. It is preferable to be inside.

  Moreover, in the synthetic resin container of the present invention, it is preferable that the lower body portion has a plurality of vacuum absorbing panels arranged around the lower body portion.

  Thus, according to the present invention, in a container made of synthetic resin having a lateral groove in the body portion of the container, the axial performance can be achieved without sacrificing other performance, that is, without increasing the number of lateral grooves arranged in the body portion. A synthetic resin container capable of increasing the buckling strength against a load can be provided.

It is a front view of the synthetic resin container of embodiment according to this invention. It is sectional drawing which follows the axial direction which expands and shows the upper trunk | drum part of FIG. It is sectional drawing which shows the cross section similar to FIG. 2 about the synthetic resin containers of other embodiment of this invention. It is sectional drawing which shows the cross section similar to FIG. 2 about the synthetic resin containers as a comparison. It is a graph which shows the result of the buckling strength test performed with respect to the synthetic resin container to which this invention is applied, and the synthetic resin container as a comparison.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, a synthetic resin container 1 according to this embodiment (hereinafter also simply referred to as “container”) includes a mouth portion 2 that forms an opening that allows the contents to be taken in and out, and A truncated conical cylindrical shoulder 3 with the mouth standing up at the upper end, a body 4 connected to the mouth 2 via the shoulder 3, and a bottom 5 closing the lower end of the body 4; The mouth portion 2, the shoulder portion 3, the body portion 4 and the bottom portion 5 are integrally formed by biaxially stretching blow-molding a preform made of a thermoplastic synthetic resin such as polyethylene terephthalate. A projection 2a is formed on the outer peripheral surface of the mouth portion 2, and a cap (not shown) is plugged into the projection 2a. In addition, it replaces with the protrusion 2a of the outer peripheral surface of the opening part 2, a screw may be formed, and a cap may be screwed together so that attachment or detachment is possible. Further, in the figure, a symbol S indicates a common central axis of the mouth portion 2, the shoulder portion 3, the trunk portion 4, and the bottom portion 5.

  The body portion 4 has a waist 7 that is recessed inward in the radial direction over the entire circumference of the body portion 4 at the central portion in the axial direction S. The body portion 4 is separated from the waist 7 by the upper body portion 8 and the waist portion 8. The lower body portion 9 is divided into two parts (up and down in the axial direction S). By providing such a waist 7, the radial rigidity at the center of the torso can be increased, and when the user grips the container torso, the user can hang his fingers, The container 1 can be grasped stably.

  The upper body portion 8 is slightly smaller in diameter than the lower body portion 9, and a label (not shown) can be attached to the outer peripheral surface of the upper body portion 8 or a shrink label with thermal contraction can be attached thereto. The upper body 8 is formed with a plurality of (here, five) lateral grooves 10 that are recessed inward in the radial direction and extend over the entire circumference with a predetermined interval in the axial direction S. An annular convex portion 12 that protrudes outward in the radial direction is formed at the boundary between the waist 7 and the waist 7. In addition, the number of the lateral grooves 10 is not limited to this, and may be 4 or less to 6 or more. Further, in the illustrated example, the horizontal grooves 10 are arranged at equal intervals in the axial direction S, but the present invention is not limited to this. For example, the pitch is appropriately determined according to the rigidity (thickness) of the upper body 8. (Distance) may be changed. In addition, an annular step portion 13 having a diameter larger than that of the upper body portion 8 is formed and reinforced at a connection portion between the upper body portion 8 and the shoulder portion 3.

  The lower body portion 9 is composed of a concave wall 15a that is recessed in a dish shape toward the inside in the radial direction and a flat wall 15b that is surrounded by the concave wall 15a. And a column portion 16 that is connected to the panel 15 and serves as a support column of the body portion 4. In the illustrated example, six panels 15 are provided at equal intervals in the circumferential direction, but the number, shape, and the like of the panels 15 are not limited thereto. An annular recess 17 that is recessed inward in the radial direction is formed and reinforced at the connecting portion between the lower body portion 9 and the bottom portion 5.

  As shown in FIG. 2, the lateral groove 10 formed in the upper body portion 8 along the circumferential direction has a groove bottom formed by a single arc that protrudes inward in the container in the cross section along the axial direction S. A wall 10a and a pair of groove side walls 10b each formed by a single arc that is connected to both side walls of the groove bottom wall 10a to the side wall of the upper body 8 and protrudes outward from the container. Become.

Further, the lateral groove 10 has a groove depth d in a range of 1.5 to 2.0 mm, and a ratio R _S / of the radius of curvature R _S of the groove side wall 10b to the radius of curvature R _B of the groove bottom wall 10a. R _B is in the range of 2-3. More preferably, 1.0 mm radius of curvature _{R B} of Mizosokokabe 10a, the curvature radius _{R S} of the groove sidewalls 10b and 2.0Mm～3.0Mm. In the example of FIG. 2, the groove depth d of the lateral groove 10 is 1.5 mm, the radius of curvature _{R S} of the groove sidewall 10b is 3.0 mm, the radius of curvature _{R B} of Mizosokokabe 10a is a 1.0mm . In the example of FIG. 3, the groove depth d of the lateral groove 10 is 2.0 mm, the radius of curvature _{R S} of the groove sidewall 10b is 2.0 mm, the radius of curvature _{R B} of Mizosokokabe 10a is a 1.0mm .

If the groove depth d of the transverse groove 10 is less than 1.5 mm, the original function of the transverse groove is insufficient, the radial rigidity is lowered, and the body portion 4 is deformed into an elliptical shape or an indefinite shape in a cross section along the radial direction. If the groove depth d of the lateral groove 10 exceeds 2.0 mm, a sufficient buckling strength against the load may not be secured when a load in the axial direction S is applied to the container 1. It becomes difficult to obtain a desired groove shape during blow molding. Further, if the ratio R _S / R _{B of the} curvature radius R _S of the groove sidewall 10 b to the curvature radius R _B of the groove bottom wall 10 a is less than 2, a desired groove shape is hardly obtained at the time of blow molding, and the ratio R the amount of deflection of _{S /} R _B is the lateral grooves 10 exceeds 3 (expansion deformation amount) reduced buckling strength is may be reduced.

  Further, the vertical length L (length along the axial direction) between the boundaries between the pair of groove side walls 10b and the side wall of the upper body 8 is more preferably in the range of 5.2 mm to 6.93 mm. preferable. When the length L is less than 5.2 mm, the groove depth d becomes so deep that it becomes difficult to obtain a desired groove shape at the time of blow molding and there is a possibility that sufficient buckling strength cannot be secured. When the length L exceeds 6.93 mm, it is difficult to obtain a groove depth sufficient to bend the groove bottom wall 10a.

In the synthetic resin container 1 of this embodiment, the groove bottom wall 10a and the groove side wall 10b of the lateral groove 10 are formed by a single circular arc protruding in opposite directions, and the radius of curvature R _S of the groove side wall 10b. of, since it was 2-3 ratio _R S / _{R B} for the radius of curvature _{R B} of Mizosokokabe 10a, while constituting easily deflected the Mizosokokabe 10a against axial loading S, the groove side walls 10b That is, the lateral groove 10 is greatly expanded and contracted by deformation of the groove bottom wall 10a when the load in the axial direction S is applied to the container 1, while the groove side wall 10b causes the groove to be restored. The bottom wall 10a can be restored and supported from both sides. As a result, the cushioning property of the container 1 can be improved and the buckling strength can be greatly increased.

  Therefore, since the buckling strength can be increased by providing the lateral groove 10 that can be largely expanded and contracted in a part of the body part 4, that is, the upper body part 8, in other regions of the body part 4 where the lateral groove 10 is not provided. Can be provided with means for exhibiting other performance such as reduced pressure absorption performance, and the buckling strength against the load in the axial direction S can be increased without sacrificing the other performance.

  Moreover, according to the synthetic resin container 1 of this embodiment, since the reduced pressure absorption panel 15 is disposed on the lower body portion 9, in addition to improving the radial strength and the axial buckling strength. Thus, the vacuum absorption function can be exhibited as another performance.

  In addition, as resin which comprises the container 1, synthetic resins, such as a polypropylene and polyethylene other than a polyethylene terephthalate, can be used, About the resin to be used, it selects suitably. In addition, not only blow molding but also injection molding can be applied to the molding method, and this point is not particularly limited. Further, in this example, the lateral groove 10 is disposed only in the upper body portion 8, but of course, the lateral groove 10 can also be disposed in the lower body portion 9. The strength can be further increased.

  Next, in order to confirm the effect by this invention, since the test regarding buckling strength was done, the example is demonstrated.

Here, the test article 1 is a container made of polyethylene terephthalate according to the present invention, and has the configuration shown in FIG. 1, and specifically, the lateral groove 10 protrudes inward of the container as shown in FIG. The groove bottom wall 10a is formed by a single circular arc, and the groove bottom wall 10b is formed by a single circular arc that is connected from both ends of the groove bottom wall 10b to the side wall of the upper body 8 and protrudes outward from the container. consists of a pair of grooves side walls 10b has a groove depth d of the lateral groove 10 is 1.5 mm, and the radius of curvature _{R S} of the groove sidewall 10b is 3.0 mm, the radius of curvature _{R B} of Mizosokokabe 10a 1 0.0 mm. The vertical length L between the boundaries between the pair of groove sidewalls and the sidewalls of the upper body portion is 6.24 mm.

Moreover, the test product 2 is a container for comparison, and the basic configuration of the container is the same as the configuration shown in FIG. 1, but the groove depth d of the lateral groove 10 is 1.5 mm as shown in FIG. , and the and the curvature of the groove sidewalls 10b radius _{R S} is 3.0 mm, the radius of curvature _{R B} of Mizosokokabe 10a is 2.5 mm. The vertical length L between the boundary between the pair of groove side walls and the side wall of the upper body portion is 7.55 mm.

  The buckling strength is measured by filling the test items 1 and 2 with the specified contents and sealing them, and then gradually applying a load in the axial direction S to the container to actually measure the load when the container is buckled. It went by. The result at that time is shown in FIG. In the graph of FIG. 5, the vertical axis indicates the axial load, and the horizontal axis indicates the axial displacement when the load is applied to the container.

  As a result of the test, in the test product 2, buckling occurred in the lateral groove 10 of the upper trunk 8 at a load of 329.0N, whereas in the test product 1, no buckling occurred up to a load of 365.4N. Moreover, the buckled portion occurred not in the lateral groove 10 but in the annular step portion 13 located at the boundary between the upper body portion 8 and the shoulder portion 3. Also from this, it is clear that the effect of optimizing the cross-sectional shape of the lateral groove 10 is great.

  Thus, according to the present invention, in a synthetic resin container having a lateral groove in the container body, the seat against the axial load can be obtained without sacrificing other performance, i.e., without increasing the number of lateral grooves disposed in the body. It has become possible to provide a synthetic resin container capable of increasing the bending strength.

DESCRIPTION OF SYMBOLS 1 Synthetic resin container 2 Mouth part 3 Shoulder part 4 Trunk part 5 Bottom part 7 Waist 8 Upper trunk | drum 9 Lower trunk | drum 10 Lateral groove 10a Groove bottom wall 10b Groove side wall

Claims (4)

A mouth portion that forms an opening that allows the contents to be taken in and out; a trunk portion that is connected to the mouth portion via a shoulder portion; In the synthetic resin container, which is composed of an upper body part and a lower body part that are divided into two parts vertically, and a plurality of transverse grooves that extend over the entire circumference in the upper body part with a space in the vertical direction.
The lateral grooves are respectively connected to the groove bottom wall formed by a single circular arc that protrudes toward the inside of the container, and from both ends of the groove bottom wall to the side wall of the upper body part, and protrudes outward from the container. A pair of groove sidewalls each formed by a single circular arc,
The transverse groove has a depth in a range of 1.5 mm to 2.0 mm, and a ratio R _S / R _{B of a} curvature radius R _S of the groove sidewall to a curvature radius R _B of the groove bottom wall is 2 A synthetic resin container characterized by being in the range of ~ 3. The radius of curvature R _B of the groove bottom wall is 1.0 mm, the synthetic resin container according to claim 1.   The synthetic resin container according to claim 1 or 2, wherein a vertical length between boundaries between the pair of groove side walls and the side wall of the upper body portion is in a range of 5.2 mm to 6.93 mm.   The said lower side trunk | drum is a synthetic resin container as described in any one of Claims 1-3 which has the several pressure reduction absorption panel arranged at intervals around the lower trunk | drum.

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