JP6772459B2 - Synthetic resin container - Google Patents

Description

The present invention relates to a synthetic resin container provided with a decompression absorption panel that absorbs pressure changes in the container after the contents are filled and sealed.

Conventionally, a container made of synthetic resin, which is formed by forming a bottomed tubular preform using a thermoplastic resin such as polyethylene terephthalate and then molding this preform into a bottle shape by biaxial stretching blow molding or the like. It is generally used in a wide range of fields as a container containing various beverages and the like.

Further, when filling a container made of this kind of synthetic resin with contents, a so-called hot pack is also known in which the heat-sterilized contents are filled and sealed at a high temperature.
After filling and sealing the contents with a hot pack, the inside of the container cooled to room temperature is decompressed. Therefore, the container used for the hot pack generally deforms inward as it cools. A plurality of decompression absorption panels for reducing the volume of the container and absorbing the decrease in internal pressure are arranged on the container body along the circumferential direction (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-93556

However, in this type of synthetic resin container, attempts have been made to make the container as thin as possible in order to reduce the weight and cost by reducing the amount of resin used. In that case, the demand for such thinning is becoming more and more stringent. As the thickness of the container becomes thinner, it becomes more difficult to secure the strength of the container. For example, when a load is applied from the vertical direction, it is formed between the vacuum absorbing panels adjacent to the circumferential direction of the container body. Buckling deformation is likely to occur on the upper and lower ends of the pillar portion (see paragraph [0044] of Patent Document 1, and FIG. 1 and the like).

The present invention has been made in view of the above circumstances, and the vertical length of the container body on which the decompression absorption panel is formed is required to reduce the weight and thickness of the container, which has become more and more severe in recent years. An object of the present invention is to provide a synthetic resin container having improved load strength.

The synthetic resin container according to the present invention is a synthetic resin container having a mouth portion, a shoulder portion, a body portion, and a bottom portion, and the body portion has a cylindrical panel forming portion, and the panel forming portion is provided. Is bordered by a step portion that is recessed from the peripheral surface of the panel forming portion to form a step, and a plurality of decompression absorption panels in which the panel body is connected to the step portion are arranged along the circumferential direction. At the same time, a column portion is formed between the decompression absorption panels adjacent to each other in the circumferential direction, and the decompression absorption panel has corner portions at the upper end and the lower end and is located at at least one of the upper end and the lower end of the decompression absorption panel. The distance from the reference point located at the center of the decompression absorption panel in the width direction on the line segment where the corner portion is orthogonal to the height direction passing through the start end of the corner portion to the peripheral edge forming the contour of the corner portion is , It is formed so as to gradually become longer from the start end to the end of the corner portion, is located on the outer peripheral side of the decompression absorption panel, and has a convex shape protruding outward from the container along the contour of the decompression absorption panel. The ribs are provided at the corners located at least at the upper end or the lower end.

According to the present invention, it is possible to secure sufficient vertical load strength while reducing the weight and thickness of the container.

It is a front view which shows the outline of the synthetic resin container which concerns on embodiment of this invention. It is explanatory drawing which shows the projection of the outline of the decompression absorption panel of the synthetic resin container which concerns on embodiment of this invention. It is a front view which shows the outline of the modification of the synthetic resin container which concerns on embodiment of this invention. FIG. 3 is an end view of AA in FIG. It is a front view which shows the outline of the other modification of the synthetic resin container which concerns on embodiment of this invention. It is a front view which shows the outline of the comparative example. It is explanatory drawing which shows the projection of the contour of the decompression absorption panel of the comparative example.

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

In the present embodiment, for the container 1, for example, a bottomed tubular preform is formed by injection molding or compression molding using a thermoplastic resin, and this preform is formed by biaxial stretching blow molding or the like. It is manufactured by molding into a predetermined container shape having a mouth portion 2, a shoulder portion 3, a body portion 4, and a bottom portion 5 as shown in the above.

In manufacturing such a container 1, any resin capable of blow molding can be used as the thermoplastic resin to be used. Specifically, thermoplastic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polylactic acid or copolymers thereof, and those blended with these resins or other resins are preferable. Is. In particular, ethylene terephthalate-based thermoplastic polyesters such as polyethylene terephthalate are preferably used. Further, acrylonitrile resin, polypropylene, propylene-ethylene copolymer, polyethylene and the like can also be used.

In the example shown in FIG. 1, a screw portion 21 for attaching a lid (not shown) is formed in the mouth portion 2, and the lower end side of the mouth portion 2 is a truncated cone whose diameter increases toward the body portion 4. It is connected to the shaped shoulder portion 3.

Further, the body portion 4 is a portion that occupies most of the height direction of the container 1, and six-sided decompression absorption panels 6 are arranged at predetermined intervals along the circumferential direction in the cylindrical panel forming portion 40. A pillar portion 7 is formed between the decompression absorption panels 6 adjacent to each other in the circumferential direction. The container 1 provided with such a body portion 4 has a so-called round bottle-shaped container shape in which the cross-sectional shape thereof is generally rounded.

Here, the height direction means a direction orthogonal to the horizontal plane when the container 1 is upright on the horizontal plane with the mouth portion 2 facing up, and in this state, the vertical, horizontal, vertical and horizontal directions of the container 1. Shall be specified.

The panel forming portion 40 may be formed so that its outermost peripheral diameter is constant along the height direction. For example, the outermost outer peripheral diameter is such that the central portion in the height direction bulges or dents. May be formed so as to change along the height direction.

Further, in the example shown in FIG. 1, bead-shaped annular portions 41 and 42 are provided on the upper end side of the body portion 4 connected to the shoulder portion 3 and the lower end side of the body portion 4 connected to the bottom portion 5, respectively. Although the load-bearing strength against a load from the lateral direction (direction orthogonal to the height direction) is increased, these ring portions 41 and 42 can be omitted as appropriate. That is, the body portion 4 may have a cylindrical panel forming portion 40 in which a plurality of decompression absorbing panels 6 are arranged along the circumferential direction.

In the present embodiment, the decompression absorption panel 6 is bordered along the contour by a step portion 60 that is recessed from the cylindrical peripheral surface of the panel forming portion 40 to form a step, and the step portion 60 has a step portion 60. The panel body 61 is connected.

In the present embodiment, the specific shape of the panel body 61 is not particularly limited as long as the decompression absorption panel 6 can exhibit the desired decompression absorption performance. Therefore, in the example shown in FIG. 1, the illustration of the specific shape of the panel body 61 is omitted.

Further, the decompression absorption panel 6 has a contour in which the upper and lower corners are rounded (in the illustrated example, a rectangular contour with rounded corners). Then, the width of the decompression absorption panel 6 is reduced in the vertical direction in the height direction by rounding the corners, and the position where the width of the decompression absorption panel 6 starts to be reduced is set as the start end IP of the corners, and the corners are rounded. The other end of the compartment is the termination EP.

The corner portion of the decompression absorption panel 6 has the outline of the corner portion from the reference point RP located at the center in the width direction of the decompression absorption panel 6 on the line segment L orthogonal to the height direction passing through the start end IP of the corner portion. The distance d to the peripheral edge to be formed is formed so as to gradually increase from the start IP of the corner portion toward the end EP.

In the round bottle-shaped container 1 in which a plurality of decompression absorption panels 6 are arranged on the body 4 along the circumferential direction, a load is applied to the container 1 from the vertical direction as the weight and thickness of the container are reduced. The stress is concentrated on the upper and lower end portions of the pillar portion 7 formed between the decompression absorption panels 6 adjacent to each other in the circumferential direction, that is, the portions connected to the corner portions of the decompression absorption panel 6 of the pillar portion 7. It was easy, and the site tended to be the starting point of buckling deformation.

Therefore, in the present embodiment, as described above, the distance d from the reference point RP to the peripheral edge forming the contour of the corner portion of the corner portion of the decompression absorption panel 6 ends from the start end IP of the corner portion. By forming it so as to gradually become longer toward EP, the occurrence of buckling deformation on the upper and lower end sides of the pillar portion 7 formed between the pressure reducing absorption panels 6 adjacent in the circumferential direction is suppressed.

As a mode in which the distance d from the reference point RP to the peripheral edge forming the contour of the corner portion gradually increases from the start end IP of the corner portion toward the end EP, the distance d is constantly changing and gradually increases. The distance d does not change in a certain section and has the same length, and the distance d becomes longer in the next terminal EP side section. included. That is, when the distance d is represented by the function F (θ) with the angle θ with respect to the line segment L as a variable, the relationship of F (θb) −F (θa) ≧ 0 (where θb> θa) is established. Just do it.

In the present embodiment, the contour of the corner portion of the decompression absorption panel 6 is vertically projected onto a plane including the center line S along the height direction passing through the center in the width direction of the decompression absorption panel 6 and the center axis C of the container 1. Then, the projection becomes an arc shape as shown in FIG. Such a projection is also a projection of the contour of a portion of the pillar portion 7 connected to the corner portion, and by forming the corner portion of the decompression absorption panel 6 into the above-mentioned shape, the projection is curved with a larger radius of curvature R. It becomes an arc shape. By doing so, it is possible to relax the concentration of stress on the portion of the pillar portion 7 connected to the corner portion, and thereby buckling starting from the portion of the pillar portion 7 connected to the corner portion. Deformation can be suppressed.
In FIG. 2, the contour of the container 1 is shown by a chain line, the projection of the contour of the decompression absorption panel 6 is shown by a thick line, and the contour of the decompression absorption panel 6 is superimposed on the projection of the contour of the corner portion to form an arc. The auxiliary line of is shown by a thin line.

Here, for comparison, instead of the decompression absorption panel 6 in the present embodiment, the distance d from the reference point RP to the peripheral edge forming the contour of the corner portion gradually increases from the start end IP of the corner portion toward the end EP. FIG. 6 shows an example of the container 1C in which the decompression absorption panel 6C having corners formed so as to be short is arranged, and FIG. 7 shows the projection of the contour of the decompression absorption panel 6C corresponding to FIG. 2 at this time. .. In such a comparative example, the radius of curvature r of the projection curved in an arc shape is smaller than the radius of curvature R of the present embodiment, and the portion connected to the corner portion of the decompression absorption panel 6C of the column portion 7. There is a tendency for stress to concentrate easily.

As described above, according to the present embodiment, in the round bottle-shaped container 1 in which a plurality of decompression absorption panels 6 are arranged on the body portion 4 along the circumferential direction, they are adjacent to the load from the vertical direction. It is possible to alleviate the stress concentration on the upper and lower ends of the pillars 7 formed between the vacuum absorption panels 6, which is sufficient while reducing the weight and thickness of the container 1. It is possible to secure a sufficient vertical load strength.

Then, in forming the corner portion of the decompression absorption panel 6 as described above so that such an effect can be satisfactorily achieved, the corner portion is formed in the height direction from the end EP of the corner portion to the start end IP of the corner portion. The length Lv of the perpendicular line drawn to the orthogonal line segment L is Lv / Lh = 1.05 to 4 with respect to the length Lh from the start IP of the corner portion to the reference point RP. And the terminal EP are preferably defined to form a corner portion.

Further, when the corner portion of the decompression absorption panel 6 is formed as described above, the width of the upper and lower end portions of the pillar portion 7 formed between the adjacent decompression absorption panels 6 becomes wider, and the area of that portion becomes larger. Become. Therefore, when molding the container 1, there is a concern that the upper and lower ends of the pillar portion 7 tend to stick to the molding surface of the molding die.

If such sticking to the molding surface occurs, a load trying to peel it off is applied to the portion sticking to the molding surface at the time of mold release, and a distortion called sink mark occurs. Sometimes. Then, such sink marks tend to occur as the thickness of the container 1 becomes thinner, and when the sink marks occur, not only the appearance of the container 1 is impaired but also the strength is lowered.

In order to avoid such a problem, when forming the corner portion of the decompression absorption panel 6 as described above, as shown in FIGS. 3 and 4, the corner portion is located on the outer peripheral side of the decompression absorption panel 6. However, it is preferable to provide the convex rib 8 protruding outward from the container along the contour of the decompression absorption panel 6.
Note that FIG. 4 is an end view of AA in FIG. 3, but in FIG. 4, the wall thickness of the container 1 is omitted, and the thickness of the container 1 is omitted, and the panel forming portion 40 is overlapped with the end face to surround the cylindrical peripheral surface of the panel forming portion 40. The virtual line extending in the direction is shown by a chain line.

By doing so, it is possible to prevent the upper and lower ends of the column portion 7 from sticking to the molding surface of the molding die, suppress the occurrence of sink marks, and prevent the strength from being lowered. Further, by providing such a convex rib 8, it is possible to improve the strength of the upper and lower ends of the pillar portion 7, which is combined with the fact that the corner portion of the decompression absorption panel 6 is formed as described above. Therefore, more sufficient vertical load strength can be secured.
As shown in FIG. 5, such a convex rib 8 may be provided over substantially the entire circumference of the decompression absorption panel 6.

Although the present invention has been described above with reference to preferred embodiments, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. Nor.

For example, in the above-described embodiment, the six-sided decompression absorption panel 6 is provided on the body portion 4, but the present invention is not limited to this. The number of panels of the decompression absorption panel 6 arranged on the body portion 4 can be appropriately selected in the range of four to eight surfaces.

Further, in the above-described embodiment, an example in which the contour of the decompression absorption panel 6 is formed in a rectangular shape with rounded corners based on a rectangle has been illustrated, but the contour of the decompression absorption panel 6 has been described. The base figure is not limited to a rectangle, and may be a square, an isosceles trapezoid, or the like. Further, the decompression absorption panel 6 is preferably formed in line symmetry having an axis of symmetry along the height direction, but may have a slight inclination with respect to the height direction, and the decompression absorption in this case. The figure on which the contour of the panel 6 is based is a parallelogram.

Further, in forming the corner portion of the decompression absorption panel 6 as described above, in the example illustrated in the above-described embodiment, the terminal EPs of the left and right corner portions overlap, and the decompression absorption panel 6 is located on the upper end side and the lower end side. Although no linear portion remains, the terminal EPs at the left and right corners may be separated so that linear portions remain on the upper end side and the lower end side of the decompression absorption panel 6. On the other hand, in the example illustrated in the above-described embodiment, the start end IPs of the upper and lower corner portions are separated, and a linear portion remains on the side side of the decompression absorption panel 6, but the start end IPs of the upper and lower corner portions are left. May be overlapped so that no linear portion remains on the side side of the decompression absorption panel 6.

Further, in the above-described embodiment, the distance d from the reference point RP to the peripheral edge forming the contour of the corner portion is similarly changed from the start end IP of the corner portion to the end EP of all the corner portions of the decompression absorption panel 6. Although it is formed so as to gradually become longer toward the end, the same applies only to the corner portion located at one of the upper end or the lower end of the decompression absorption panel 6 depending on the shape of the other part of the container 1. It can also be formed.

That is, the present invention has corners at the upper and lower ends of the decompression absorption panel 6, and the corners located at at least one of the upper end and the lower end of the decompression absorption panel 6 pass through the start end IP of the corners in the height direction. The distance d from the reference point RP located at the center of the decompression absorption panel 6 on the line segment L orthogonal to the corner portion to the peripheral edge forming the contour of the corner portion is from the start end IP of the corner portion to the end EP. As long as it is formed so as to be gradually lengthened, the configuration of other details can be appropriately changed without being limited to the above-described embodiment. In addition, the detailed configurations described in the above-described embodiments can be appropriately selected and combined.

The present invention as described above can be applied to a synthetic resin container provided with a decompression absorption panel that absorbs a pressure change in the container after filling and sealing the contents.

1 Container 2 Mouth 3 Shoulder 4 Body 40 Panel forming 5 Bottom 6 Decompression absorption panel 60 Steps 7 Pillars 8 Convex rib IP Corner start EP Corner end RP Reference point L Start height passing through IP Line segment Lv orthogonal to the vertical direction Length of perpendicular line drawn from end EP to line segment L Lh Length from start IP to reference point RP d Distance from reference point RP to the peripheral edge forming the contour of the corner

Claims (3)

A synthetic resin container having a mouth, shoulders, body, and bottom.
The body portion has a cylindrical panel forming portion and has a cylindrical panel forming portion.
The panel forming portion is bordered by a step portion that is recessed from the peripheral surface of the panel forming portion to form a step, and a plurality of decompression absorption panels in which the panel body is connected to the step portion are formed along the circumferential direction. Along with being arranged, a pillar portion is formed between the decompression absorption panels adjacent in the circumferential direction.
The decompression absorption panel has corners at the upper and lower ends.
The corner portion located at at least one of the upper end or the lower end of the decompression absorption panel is located at the center in the width direction of the decompression absorption panel on a line segment orthogonal to the height direction passing through the start end of the corner portion. , The distance to the peripheral edge forming the contour of the corner portion is formed so as to gradually increase from the start end to the end of the corner portion.
Convex ribs located on the outer peripheral side of the decompression absorption panel and projecting outward from the container along the contour of the decompression absorption panel are provided at the corners located at least at the upper end or the lower end.
Synthetic resin container. The length Lv of a perpendicular line drawn from the end of the corner portion to a line segment orthogonal to the height direction passing through the start end of the corner portion is the length Lh from the start end of the corner portion to the reference point. The synthetic resin container according to claim 1, wherein Lv / Lh = 1.05 to 4. The synthetic resin container according to claim 1 or 2, wherein the convex rib extends from the corner portion located at the upper end of the decompression absorption panel to the corner portion located at the lower end. ..

Images