Plastic bottles

Abstract

Plastic bottles (1) which are characterized in that: they are composed of neck (2), shoulder (3), body (4) and bottom (5); the cross-sectional shape at the body (3) is a regular polygon, the number of angles of which is an even number of not less than 4 nor more than 32; each angle of the polygon is rounded off by an arc (8) whose radius is not longer than half the radius of a circle circumscribed about the cross-sectional shape at body (3); cross-sectional shapes have the same shape at any portion of body (3); circles circumscribed about the cross-sectional shapes are identical with one another; the circumscribed circles have a center on the vertical central axis of body (3); and the cross-sectional shape of body (3) rotates around said central axis in proportion to height along said central axis.

Description

TECHNICAL FIELD [0001] This invention relates to plastic bottles to be used as liquid containers, more specifically to plastic bottles for beverages which are to be hot-filled or aseptic-filled. BACKGROUND ART [0002] Biaxially stretched blow-molded bottles made from polyethylene terephthalate (PET) are widely used as beverage containers. Containers are usually filled with beverage product either by hot-filling or by aseptic-filling. In hot-filling, biaxially stretched blow-molded containers are filled with beverage which has been heated to around 90° C., sealed with a cap, and are then cooled. In aseptic-filling, containers are sterilized, and are then filled in the resultant aseptic environment. Hot-filling has been accompanied with a problem that containers expand when filled or capped, and that, when cooled, containers shrink due to reduced pressure inside. Also aseptic-filling has had a problem that containers shrink due to reduced pressure which is caused by the contents' absor...

AI Technical Summary

Benefits of technology

[0010] In order to resolve the above-mentioned problems with conventional bottles, this invention is to provide, at a low price, plastic beverage bottles which, in aseptic-filling and hot-filling, are not deformed awkwardly by the change in internal pressure which is caused by warming or cooling, are capable of absorbing decompressed volume, are so well-designed as to avoid poor appearance, and are easy for consumers to handle, free from tearing or peeling of shrink-labels during transportation, have high load capacity strength and horizontal compression strength as well as package strength, and bring no problem in bottle-filling line.

[0016] This invention provides plastic beverage bottles which, in aseptic-filling and hot-filling, are not deformed awkwardly by the change in internal pressure which is caused by warming or cooling, are so well-designed as to avoid poor appearance, and are easy for consumers to handle, free from peeling of shrink-labels during transportation, have high load capacity strength, and bring no problem in bottle-filling line.

[0017] In conventional plastic bottles, when internal pressure changes, central axis of neck section leans out of the central axis of body of the bottle, and, thus, deformation occurs. In the bottle of this invention, plural numbers of helixes are wound tighter around the body, with the result that the height of plastic bottle decreases, and, accordingly, volume is decreased. Or, on the contrary, plural numbers of helixes are wound more loosely, with the result that the height of plastic increases, and, accordingly, volume is increased. Such deformation prevents the plastic bottle of this invention from deforming in such a way that the central axis of its neck section leans out of central axis of body section.

Problems solved by technology

Hot-filling has been accompanied with a problem that containers expand when filled or capped, and that, when cooled, containers shrink due to reduced pressure inside.

Also aseptic-filling has had a problem that containers shrink due to reduced pressure which is caused by the contents' absorbing oxygen in the head space.

This causes a problem that containers swell due to increased internal pressure when warmed.

These approaches require a large absorption panel, which compromises the appearance of bottle.

Also from the viewpoint of overall design, these bottles lack continuity in outline, and therefore look awkward.

Hence, when shrink-label is put on bottle for surface decoration, gaps can be made between the bottle and the shrink-label to cause a problem that bottle becomes difficult to handle, that shrink-label is torn during transportation, and that moisture which has been trapped in these gaps is difficult to be removed.

If no heat insulation panel is used so that the bottle may have a cylindrical shape by which to avoid the above-mentioned problems, bottles shrink unevenly when decompressed, compromising their appearance.

Besides, if the amount of material resin of bottle is reduced, longitudinal buckling strength is decreased, and, therefore, bottles crush when stacked.

Due to these problems, the only realistic way to make bottles withstand decompression has been to increase the amount of material resin of bottle, which is undesirable from the viewpoint of productivity and economy.

This solution has a problem that bottles of this shape has low strength due to the lack of heat insulation panel.

Hence, each face which constitutes side wall is deflected in vertical direction under reduced pressure, resulting in conspicuous deformation.

When reduced pressure is applied to bottle, however, high rigidity may give rise to buckling in thin areas alone, which leads to severe deformation.

Furthermore, since vertical section has a terraced shape where triangular faces are complicatedly arranged, there is a concern that, in an sterilization step of aseptic filling, the flow of sterilizing liquid may be insufficient in some areas, or that the liquid may be incompletely rinsed away.

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