JP6566604B2 - Synthetic resin flat bottle bottom shape - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a bottom shape of a flat bottle made of a synthetic resin, which is a flatly formed bottle and whose deformation of the bottom portion is suppressed even when the contents are hot-filled.

  Conventionally, as a method for filling a synthetic resin bottle with contents such as fruit juice and tea that require sterilization, there is a so-called heat filling method, and the content is at a temperature of 70 ° C. to 95 ° C. The product is filled in a bottle, capped and sealed, and then cooled. As the hot filling bottle, a so-called PET bottle using polyethylene terephthalate is often used. Especially for PET bottles used for heat filling (hereinafter referred to as “heat-resistant PET bottles”), since the inside of the bottle is depressurized by cooling, it is necessary to provide a reduced pressure absorption surface for absorbing the reduced pressure inside the bottle. Conventionally, circular or polygonal bottles in a cross-sectional view provided with a reduced pressure absorption surface have been widely used. However, so-called flat heat-resistant PET bottles that are elliptical or rectangular in cross-sectional view are not widely used. A heat-resistant PET bottle is molded by heat-setting a bottomed cylindrical preform formed by injection molding by biaxial stretching blow. However, the round or polygonal bottle has a uniform or almost uniform stretching ratio. Therefore, it can be molded relatively without uneven thickness. In contrast, flat heat-resistant bottles have different draw ratios, and therefore tend to cause uneven thickness in the minor axis direction where the draw ratio is small and in the major axis direction where the draw ratio is large. As a result of deterioration, when heat filling, the PET softens and deforms so that the bottom wall with insufficient reinforcement bulges outward. As a result, a part of the bottom wall protrudes downward from the grounding part. As a result, a so-called bottom-down occurs that causes a failure in grounding stability. A method of forming a rib to prevent the bottom from falling is known (for example, Patent Document 1).

  However, in the heat-resistant flat bottle, since the draw ratios in the major axis direction and the minor axis direction described above are different, there is a problem that bottom shape is poor, and even if a rib is provided on the bottom part, the bottom falls. .

JP 2007-297058 A

  The present invention has been made in view of such circumstances, and an object thereof is to provide a bottom shape of a synthetic resin flat bottle excellent in grounding stability by suppressing the occurrence of bottom falling in a heat-resistant flat bottle. It is.

As a means for solving the above problems, the present invention has a mouth tube part, a shoulder part, a body part, and a bottom part , and the body part and the bottom part have a short side and a long side in a cross-sectional view perpendicular to the bottle axis. A bottom shape of a flat bottle made of synthetic resin of a biaxial stretch blow molding formed in a rectangular shape or an elliptical shape having a short axis and a long axis ,
The bottom part extends from the grounding part to the center from the inner end part in the bottle radial direction of the tapered peripheral wall part, the tapered peripheral wall part that extends from the inner side in the bottle radial direction and extends upward from the grounding part. A central bottom wall,
The taper peripheral wall part that appears in the longitudinal section cut by a line that is perpendicular to the bottle axis and parallel to the short side or the short axis is a straight line that inclines inward in the bottle radial direction from the grounding part toward the center bottom wall. An inclination angle with respect to a line extending in a shape and perpendicular to the bottle axis is formed to be 45 degrees or more and 60 degrees or less ,
Three ribs whose width gradually decreases toward the bottle shaft on the opposite surface of the tapered peripheral wall portion centering on the bottle shaft extend radially within the tapered peripheral wall portion, and the central rib of the three ribs is a bottom shape of the synthetic resin flat bottle, characterized in that you are to extend to the long or major axis and a direction parallel to the bottom view.

According to this configuration, the bottom wall is sufficiently reinforced when the contents were hot filling, or to reach a part of the bottom wall disposed position of the ground portion, or in or protrudes below the ground portion In addition, it is possible to prevent a bottom fall that leads to a failure in grounding stability and to obtain excellent grounding stability.

Oite this onset Ming, it is possible to suppress the occurrence of the bottom drop in heat flattened bottle, it has become possible to ensure excellent ground stability.

By was 60 degrees or less than 45 degrees tilt oblique angle of the tapered wall portion appearing on longitudinal section taken along a line that forms a parallel to the short side or minor axis as well as perpendicular to the bottle axis, the bottom wall is reinforced It is possible to prevent the bottom from falling, and high grounding stability can be obtained. Furthermore, it becomes excellent in releasability from the mold after biaxial stretch blow molding.

In the facing surface of the tapered peripheral wall portion centered on the bottle shaft, ribs extending radially in the region of the tapered peripheral wall portion have a shape in which the width gradually decreases toward the bottle shaft, and three ribs are provided on the facing surface, and Since the center rib of the three ribs is configured to extend in a direction parallel to the long side or the long axis in the bottom view, the bottom wall is sufficiently reinforced, and deformation of the bottom wall can be suppressed. As a result, bottom-out can be prevented and high grounding stability can be achieved.

It is a front view of one Example of the synthetic resin flat bottles which concern on this invention. It is a side view of the flat bottle shown by FIG. It is a top view of the flat bottle shown by FIG. It is a bottom view of the flat bottle shown by FIG. Showing the vicinity of the bottom of the flat bottle, (a) shows the longitudinal sectional view of a long side portion, (b) is a longitudinal sectional view of the short sides.

  Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show one embodiment of a synthetic resin flat bottle according to the present invention. FIG. 1 is a front view, FIG. 2 is a side view, FIG. 3 is a top view, and FIG. FIG. 5A is a longitudinal sectional view at the long side portion of the bottom portion, and FIG. 5B is a longitudinal sectional view at the short side portion of the bottom portion.

  As shown in FIGS. 1 and 2, the flat bottle 1 according to the present invention includes a mouth tube part 2, a shoulder part 3, a trunk part 4, and a bottom part 5. The mouth tube part 2, the shoulder part 3, the body part 4 and the bottom part 5 are connected in this order with their respective central axes positioned on a common axis.

  Hereinafter, the common axis is referred to as a bottle axis O, and the mouth tube part 2 side is defined as the upper side and the bottom part 5 side is defined as the lower side along the bottle axis O direction. A direction perpendicular to the bottle axis O is a bottle radial direction, and a direction around the bottle axis O is a bottle circumferential direction.

In addition, the flat bottle 1 is a biaxial stretch blow molding of a preform formed into a bottomed cylindrical shape by injection molding, and is integrally formed of a synthetic resin material. Further, a cap (not shown) is fitted to the mouth tube part 2. Further, for the flat bottle 1, the shoulder 3, the body 4, and the bottom 5 are each formed in an elliptical shape or a rectangular shape in cross-sectional view perpendicular to the bottle axis O. Note that in the rectangular shape, the long side portion of the long sides, and short side part has short sides.

The body part 4 includes an upper body part 4 </ b> A connected to the shoulder part 3, a middle part body part 4 </ b> B at the center part, and a lower body part 4 </ b> C connected to the bottom part 5. The middle body part 4B is smaller in diameter than the upper body part 4A and the lower body part 4C so as to be easily carried. Further, the body portion 4 is composed of front and rear wall portions 4a and the side wall portion 4b of the short sides of the long sides.

As shown in FIGS. 4 and 5, the bottom wall of the bottom part 5 includes a grounding part 6, a tapered peripheral wall part 8, and a central bottom wall 9 at the outer peripheral edge part. The grounding portion 6 is a surface on the outer peripheral edge side of the bottom portion 5 where the flat bottle 1 is actually grounded, and is a surface that affects the grounding stability of the flat bottle 1 . The tapered peripheral wall portion 8 extends from the ground contact portion 6 to the outer end portion of the central bottom wall 9 in an upward direction from the inner side (inner end portion) in the bottle radial direction. Tapered peripheral wall 8, a short side portion smell Te, extends at a small angle of inclination from the ground portion 6 to the front of the outer end portion of the rib 7, then extends at a larger angle of inclination. Ribs 7 arranged in the short side portion of the tapered wall portion 8, the depression inside the side of the bottle, and Na a concave groove as viewed from the bottom. As shown in FIG. 4, each rib 7 has a shape in which the width gradually decreases toward the bottle axis O. The central bottom wall 9 is formed in a disk shape and extends from the inner end of the tapered peripheral wall 8 in the bottle radial direction toward the center (bottle axis O) .

The tapered peripheral wall portion 8 is gradually reduced in diameter from the lower side toward the upper side. And in the long side part of the taper surrounding wall part 8, it extends so that it may incline toward the inner side of the bottle radial direction toward the center bottom face wall 9 from the earthing | grounding part 6. FIG. In this case, it is essential that the inclination angle α of the tapered peripheral wall portion 8 with respect to a line orthogonal to the bottle axis O is greater than 30 degrees and less than 90 degrees. If the tilt angle α is 30 degrees or less, the tilt angle α is small when the synthetic resin material is softened by heat filling. Become. Further, when the inclination angle α is a small angle of 30 degrees or less, the reinforcing effect on the bottom wall is lowered. On the other hand, when the inclination angle α is larger than 90 degrees, the releasability from the mold after biaxial stretching blow is inferior. The inclination angle α is preferably 40 degrees or greater and 75 degrees or less, and more preferably 45 degrees or greater and 60 degrees or less from the viewpoint of prevention of bottoming out or releasability. Note that the inclination angle α in the present embodiment shown in FIG. 2 is 45 degrees.

In addition, it is essential for the short side portion of the tapered peripheral wall portion 8 to radially extend two or more ribs 7 on the opposite surface of the tapered peripheral wall portion 8 with the bottle axis O as the center. As long as the rib 7 extends around the bottle axis O, its arrangement is not limited, but from the viewpoint of reinforcing the bottom wall and shapeability, it is usual to provide the rib 7 at both ends of the short side. In order to reinforce the bottom wall, it is preferable that three or more ribs 7 be radially extended on the opposite surfaces of the tapered peripheral wall 8. As in the present embodiment shown in FIG. 4, three ribs 7 extending radially from the opposite sides and the center of the short side portion on the opposite side of the tapered peripheral wall portion 8 are arranged in a reinforcing balance on the bottom wall. Are better.

The bottom wall of the bottom portion 5 of the present embodiment has two or more ribs 7 extending radially from the opposite side of the tapered peripheral wall portion 8 around the bottle axis O at the short side portion, and further the bottle at the long side portion. by largely less than 90 degrees from the 30 degree inclined angle α of the tapered peripheral wall 8 for a line perpendicular to the axis O, of the bottom wall by which can reinforce the bottom wall of the tapered peripheral wall 8 and the central bottom wall 9 Deformation is suppressed, thereby making it difficult to cause bottoming. Thereby, even if the synthetic resin material is softened, it is possible to prevent the bottom from falling. For this reason, stable grounding performance can be ensured, and it is possible to sufficiently cope with heat filling of the contents (for example, 70 to 95 ° C.).

The flat bottle 1 of this embodiment has a specified amount of 400 ml, the short side of the bottom 5 in FIG. 4 is 60.2 mm, and the long side is 77.8 mm. Also, the flat bottle of the present embodiment, the following amounts provisions 1000 ml, the ratio of the short side and the long side is 1: 1.2 to 1: can be applied in a range of 1.4.

As Comparative Example 1, two or more ribs 7 are radially extended on the opposite side of the short side portion of the tapered peripheral wall portion 8 to form a flat bottle with an inclination angle α of the tapered peripheral wall portion 8 of 30 degrees. The product was hot filled. However, since the inclination angle α is out of the range of the present invention, a bottom drop occurs and a flat bottle with unstable grounding is obtained.
Further, as Comparative Example 2, a flat bottle was formed by extending two ribs 7 on the long sides of the tapered peripheral wall 8 and extending the inclined angle α of the tapered peripheral wall 8 to 45 degrees. However, since the rib 7 is extended to the long side instead of the short side , a flat bottle with poor grounding stability was formed because of poor shapeability in the vicinity of the grounding part during biaxial stretching blow.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above embodiment, the shape of the rib 7 on the short side portion of the tapered peripheral wall portion 8 is gradually enlarged toward the outside in the bottle radial direction, but may be gradually reduced in diameter. Further, the diameter may be constant without being enlarged or reduced. The rib 7 is not limited to a concave shape, and may be a convex shape.

  Further, in order to prevent the bottles from being deformed by colliding with each other in the conveyance process after the bottle molding, the annular groove ribs are continuously formed over the entire circumference in the upper trunk portion 4A and the lower trunk portion 4C. It doesn't matter.

  Further, in order to further improve the vacuum absorption, a vacuum absorption surface may be provided on the front and rear wall portions 4a and the side wall portions 4b of the middle barrel portion 4B.

  Moreover, as a synthetic resin material which forms the flat bottle 1, you may change suitably, such as a polyethylene terephthalate, a polyethylene naphthalate, an amorphous polyester, or these blend materials, for example. Further, the flat bottle 1 is not limited to a single layer structure, and may be a laminated structure having an intermediate layer. Examples of the intermediate layer include a layer made of a resin material having a gas barrier property, a layer made of a recycled material, or a layer made of a resin material having an oxygen absorption property.

Further, in the above embodiment, so that fitting the cap is provided an engaging protrusion on the upper surface end of the mouth tube portion 2, instead of the engagement protrusion, using a screw cap and screwed a screw It doesn't matter if you do.

  As described above, in the present invention, it is possible to suppress the occurrence of bottom falling in a heat-resistant flat bottle and to provide a bottom shape that provides excellent grounding stability. Can be expected.

1: flat bottle 2: mouth tube part 3: shoulder part 4: trunk part 4A: upper trunk part 4B: middle trunk part 4C: lower trunk part 4a: front and rear wall part 4b: side wall part 5: bottom part 6: grounding part 7: Rib 8: Tapered peripheral wall 9: Center bottom wall O: Bottle axis α: Inclination angle

Claims (1)

A cross section having a mouth tube part (2), a shoulder part (3), a body part (4) and a bottom part (5) , wherein the body part (4) and the bottom part (5) are orthogonal to the bottle axis (O). Bottom shape of synthetic resin flat bottle (1) of biaxial stretch blow molding formed in a rectangular shape having a short side and a long side or an elliptical shape having a short axis and a long axis. Because
The bottom part (5) includes a grounding part (6) located at an outer peripheral edge part, a tapered peripheral wall part (8) extending from the grounding part (6) from the inside in the bottle radial direction and extending upward, and the tapered peripheral wall A central bottom wall (9) extending toward the center from the inner end of the bottle (8) in the radial direction of the bottle,
Said tapered wall portion appearing on longitudinal section taken along a line that forms a parallel to the short side or the short axis (8), said central bottom surface from the ground part (6) as well as perpendicular to the bottle axis (O) the inclination angle (alpha) with respect to a line perpendicular to the bottle axis (O) is formed below 60 degrees 45 degrees with linearly extending to be inclined toward inwardly of the bottle radial to the wall (9) ,
Three ribs (7) whose width gradually decreases toward the bottle shaft (O) on opposite sides of the tapered peripheral wall portion (8) centering on the bottle shaft (O) are provided on the tapered peripheral wall portion (8). A radial rib extends in the region, and a central rib (7) of the three ribs (7) extends in a direction parallel to the long side or the long axis in a bottom view. The bottom shape of a synthetic resin flat bottle.

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