JP2010500242A - Hollow body bottom obtained by blow molding or drawing blow molding of preforms - Google Patents

Abstract

Bottom (3) of hollow body obtained by blowing or drawing-blowing a preform made of thermoplastic material, said bottom (3) comprising a transversal support surface (5), and on either side of said transversal support surface (5) a transversal external edge (6), a concave internal wall with a transversal central part (11) containing a patch (12) made of material of low crystallinity, said patch (12) corresponding to the injection point of the preform; said bottom comprising a peripheral zone around the transversal support surface provided with notches (2) the extreme distal part (23) of which comes near to but does not reach the external edge (6) of the bottom (3), the extreme proximal part (24) of the notches coming in close proximity to the transversal support surface (5).

Description

The present invention relates to the technical field of hollow bodies made of thermoplastic materials, in particular containers such as bottles or bottles.

More particularly, the present invention relates to a hollow body obtained by blow molding or blow molding (injection blow) molding of a preform injected with a thermoplastic material.

Over the last few years, the production of plastic material containers based on preformed preforms has made considerable progress, especially thanks to the use of polyethylene terephthalate (PET).

Meanwhile, other materials are also woven, such as, but not limited to, polyethylene naphthalate (PEN), polypropylene (PP), polyacrylonitrile (PAN), or mixtures or superpositions of these various materials, and It has been used with some success.

In the center of the hollow body there is an area called a “patch” of some very low crystallinity resulting from a preform that is only weakly drawn during blow molding or pultrusion. The longitudinal axis of the preform is actually coincident with that of the final container. As a result, during blow molding or draw blow molding, PET drawing does not occur almost at the center of the bottom of the container and increases as it approaches the horizontal partition wall of the container.

Whatever the manufacturing method, the thermoplastic container must exhibit sufficient strength at its bottom.

Bi-directional PET exhibits sufficient mechanical and thermal strength. However, as mentioned above, the bottom of the container is much less pulled than the main body of the container, so that the dynamics and heat resistance of the bottom are lower than those of the main body.

The same problem exists for the neck. The crystallinity can be increased by heat treatment of the neck. However, heat treatment of the neck (made of non-crystalline PET) leads to isothermal crystallization, a small spherical mass state is formed, and thermosetting PET that is not translucent at all is obtained. If it is allowed that the neck of the relatively thick bottle is not translucent, the bottle bottom, which is almost non-translucent, will not be well-packed.

The bottom of the container must withstand, for example, the impact when the container containing the contents falls.

The bottom of the container must withstand the internal pressure, especially when the container contains carbonated beverages. Internal overpressure can cause temperature rises in bottled storage locations and / or shrinkage of these bottle plastic materials, but this shrinkage usually occurs between 2 or 3 weeks after their manufacture and filling. .

The bottles are placed on a pallet or bundled and transported. Therefore, except when an insertion plate is used, the bottom of the upper bottle is subjected to punching or punching stress at the same time as it rests on the stopper of the lower bottle.

Any deformation of the container bottom affects the aesthetics of the product and the stability of the container stored upright.

The bottom of the container must be strong enough to withstand creep.

The container as a whole and in particular its bottom must be strong enough to withstand the relatively severe thermal conditions encountered during hot filling or pasteurization.

The bottom must exhibit adequate deformability when heated and filled with liquids at temperatures above 94 ° C. The same applies to the subsequent cooling, and the bottom must withstand reduced pressure (vacuum compensation).

Pasteurization is performed on certain liquids that do not contain carbon dioxide (non-carbonated fruit juice) or contain gas (beer). During high temperature heating, the liquid contained in the closed container reaches, for example, a temperature of 60 to 80 ° C. in about 20 minutes to 2 hours, and this temperature varies depending on the carbon dioxide content. When pressurized dissolved gas is included in the liquid to be pasteurized (carbonated beverage, beer), the material at the bottom of the container must be able to withstand not only an increase in the capacity of the heated liquid but also an increase in the pressure of the heated gas. During cooling, the container bottom must withstand this stress because the capacity is reduced by the high temperature sterilization liquid.

Obviously, certain containers will bend at the bottom when hot filled. The bending of the bottom toward the outside, particularly in the connection area between the horizontal partition wall and the bottom of the container, does not occur uniformly around the container. As a result, the container becomes unstable. This deflection can result from stress relief introduced during the final blow of the heat-shrinked substrate.

Any deformation of the container bottom affects not only the aesthetics of the product, but also the stability of the container stored upright.

The bottom of the container may have to withstand cleaning agents in the case of reusable containers.

Thick bottom containers are also known. In particular, it has been proposed to produce a concave bottom bent inwardly called a “champagne” bottom where the thickness of the convex area is even thicker than the lateral partition wall thickness of the container, for example four times thicker. The bottom, referred to as “champagne”, provides the advantage that a continuous annular support area for bottles stored upright is created and its base is visibly stable. This solution is not satisfactory because the cost of the material is a major part of the component cost of the container. Between 1979 and 1992, the weight of PET bottles with 2 liter contents has not only changed from 65g to 52g, but there is still a need for lightweight and strong bottles. In addition, the “champagne” bottom can lose shape under temperature conditions. Cracks can appear between different thickness zones and special measures must be taken in the mold to cool the thicker zones more rapidly.

The production of containers with petal-like bottoms has been proposed.

In this case, the bottom partition wall is configured to have a convex shape on the outside, and the bottom partition wall is configured to have a convex shape on the outside, and at the same time, a projection regularly assigned to the bottom. At the same time, it usually consists of 4 to 6 legs separated by 2 by one part of the convex bottom partition wall. These petal-like bottoms are widely used in containers containing carbonated beverages. The radial hollow that separates the foot absorbs stress due to pressure during filling, and at the same time fixes the support range of the foot in a plane substantially perpendicular to the container axis. This solution is not always satisfactory. This is because the petal-like bottom can burst under the action of internal pressure. The petal-like bottom does not always withstand the overpressure due to the increased volume of bottle contents during high temperature sterilization.

Producing a bottle with a grooved bottom when the “champagne” rib type was required was also proposed. Patent document FR2717443 describes a bottle in which the ribs start around the bottom and end at the outer limit of a substantially flat annular area surrounding the amorphous concave central part. In the applicant's patent document FR 2 735 435, a container is described in which the bottom part includes a central part that is not withdrawn and a peripheral part that connects the central part to the lateral partition wall of the container. It has ribs that extend to the theoretical limit of the central part that is not pulled out. Due to this theoretical limit, a light fluctuation range of the shape and size of the center portion (patch) of the bottle bottom flowing on the same line is considered. None of the ribs end within the amorphous part.

FR2717443 FR2753435

It is clear that the bottom of the prior art is not able to recover to its original shape after dropping as well as after subsequent deformation, even if only a part of the problem is solved .

The present invention provides a strength higher than that of most currently known bottoms due to its individual properties as a whole, while at the same time reducing its shape after any forcing forces (falling, etc.) that cause its deformation. The aim is to provide a new structure for bottle bottoms that can be recovered naturally.

A uniform partition wall thickness according to the present invention will be stronger than most previously known bottle bottoms.

The required strength of the bottom according to the invention could be produced with less material thickness than most known bottoms.

Another object of the present invention is to provide a bottle having sufficient strength during heat filling and sufficient strength during high temperature sterilization.

The present invention, according to a first aspect, relates to a hollow body bottom obtained by blow molding or pultrusion blow molding of a preform with a thermoplastic material, the bottom comprising a transverse support surface as well as the transverse support surface. On both sides / outer edge in transverse direction,
Containing a concave inner partition with a transverse central portion containing a patch of low crystallinity material, this patch corresponds to the injection point of the preform, the bottom of the hollow body having its end portion at the bottom Included is a perimeter area around the transverse support surface with indentations that reach near the outer edge but do not reach themselves, with the base ends of these indentations touching the transverse support surface.

In various embodiments of the present invention, the bottoms exhibit the following characteristics combined as needed.
・ The base end of the notch does not appear on the lateral support surface.
-The notch includes a bottom partition wall and both lateral wings, and at the same time forms a symmetry plane.
• The indentation is approximately between 2 and 20 millimeters wide.
• The depth of these notches is between approximately 1 and 5 millimeters.
• The patch of low crystallinity material protrudes to the outer surface of the laterally central portion.
The outer edge is disposed at a height of h6 with respect to the lateral support surface, and the lateral central portion is disposed at a height of h11 with respect to the lateral support surface.

In one convenient embodiment of the invention, the bottom is in the form of a rotating body about an axis that is substantially perpendicular to its lateral support surface.

In one particular embodiment, the hollow body bottom is a vertical radial cross section between the outer edge and the lateral support surface,
-In the vicinity of the outer edge, substantially in contact with the direction perpendicular to the lateral support surface.

It is convenient for the bottom to be approximately parabolic in shape between the outer edge of the vertical radial section and the lateral support surface.

Conveniently, the bottom forms a continuous annular lateral support surface and no grooves or indentations are visible on this base surface.

In one embodiment, the bottom starts at the base annular surface and is directed toward the rotor axis at the same time to form a concave profile that first forms an annular step and then connects this step to the lateral central portion.

In one embodiment, the bottom includes reinforcing ribs having outer edges that extend near the lateral support surface, and these reinforcing ribs have inner edges that reach the lateral central portion but do not reach the lateral central portion. And these reinforcing ribs do not reach the lateral support surface.

The present invention, according to the second aspect, relates to a hollow body of a thermosetting material of polyester such as PET, which is obtained by blow molding or drawing blow molding of a preform.
These hollow bodies consist of a lateral partition wall and a bottom connected to the lateral partition wall, the bottom being as introduced above.

The individual features of the bottle bottom as a whole make it possible to obtain a bottom that is stronger than most of the previously known ones. A uniform partition wall thickness according to the present invention will be stronger than most conventional known bottle bottoms. A bottom according to the invention of the required strength could be produced with a lower material thickness than most known bases.

The bottle consisting of the bottom according to the present invention exhibits not only sufficient strength at the time of heat filling but also sufficient strength at the time of high temperature sterilization. The central ventilation path 19 is sufficiently reinforced especially for creep and bending due to the presence of the reinforcing rib 1.

The bottom bottle according to the invention also exhibits sufficient impact strength at the bottom of the transverse partition. The presence of the indentation can reduce the risk of plastic deformation of the bottle in the connection area between the container partition and its base. The impact is completely absorbed by the bottom and at the same time it can be “naturally” restored to its original shape after its deformation.

The shape of the bottom of the bottle does not cause weakening of the base or reduction of the surface of the base compared to the conventional bottle bottom while maintaining sufficient strength during heating and filling (vacuum action during cooling) and impact. In addition, the material weight can be reduced. As an example, a conventional hot-fill bottle 32g can be manufactured with only 26g PET, employing the bottom according to the present invention.

In the embodiment shown, the number of reinforcing ribs 1 is five and at the same time is substantially uniform and equally spaced. In other embodiments, the reinforcing ribs are more or less numerous, particularly to account for the bottom diameter. The reinforcing ribs can be of various dimensions, and the bottom partition walls of the first set of ribs may be narrower than the second set of bottom partition walls.

In the embodiment shown, the number of indentations is 10 and at the same time substantially uniform and equally spaced. In other embodiments, although not shown, the ribs expand according to the shelves arranged at midway distances between adjacent notches. With this arrangement, the ribs and notches further promote the reinforcement of the bottom of the hollow body.

Other objects and advantages of the present invention will emerge during the following description of embodiments given as non-limiting examples. This description is made with reference to the accompanying drawings. Ie

FIG. 4 is a bottom view of the bottom of a hollow body, such as a bottle, according to an embodiment of the present invention. FIG. 2 is a lateral view of the bottom shown in FIG. 1. FIG. 3 is a perspective view of the bottom shown in FIGS. 1 and 2.

The bottom 3 always has a notch 2 (in the example 10 notches) on the base side of its outer edge 6 and at the same time an axis almost perpendicular to the lateral support surface 5 where a structure with radial ribs 1 can be added in the center Form a rotating body around 4.

For this reason, the bottom 3 is described starting from its outer edge 6 and facing radially towards the rotating body axis 4.

The outer edge 6 is in the transverse direction and at the same time substantially coincides with the intersection between the bottom 3 of the container and a transverse partition (not shown). This outer edge 6 is placed at a height h6 relative to the lateral support surface 5 of the bottom 3 (the bottle containing this bottom 3 if this bottle is stored upright).

Between the outer edge 6 and the transverse support surface 5, the bottom 3 shows a substantially parabolic outline 7 in a vertical radial section. In the vicinity of the outer edge 6, this outer shape 7 is in contact with a substantially vertical direction 8 of the transverse support surface 5. In the vicinity of the transverse support surface 5, the outer shape 7 substantially contacts the transverse support surface 5. The contour 7 thus ensures a solution of continuity without disturbing the curvature between the transverse partition wall (not shown) of the container and the transverse support surface 5.

The bottom 3 forms an annular and continuous shape lateral support surface 5. Starting from this annular surface 5 and simultaneously toward the axis of rotation 4, the bottom 3 forms an annular step 9 having a width (measured in the radial direction) approximately equal to the width of the transverse support surface 5. The annular stage 9 makes it possible to form the bellows-like bottom 3 under the action of overpressure or vacuum in the hollow body having such a bottom.

Starting from this annular stage 9 and toward the axis of rotation 4 at the same time, the bottom 3 then forms a substantially parabolic contour 10 in the vertical radial direction and then forms a transverse central part 11.

The transverse central part 11 is situated at a height of h11 with respect to the transverse support surface 5, this height h11 being only somewhat relative to the height h6 of the outer edge 6.

The axial patch 12 protrudes in the transverse central part 11, which protrudes downwards, that is, outside the container with the bottom 3.

Next, the notches 2 constituting the core of the present invention will be described.

These notches 2 extend in the radial direction. These include the bottom partition wall 20 and the lateral blades 21,22. Each notch forms a plane that is symmetrical in the vertical radial direction. The end portions 23 of these notches reach the vicinity of the outer edge 6 of the bottom 3 but do not reach itself. These notches thus have a starting point that is close to the vertical but away from the seam. It is preferred that the outer base 24 portion of the notch reaches the vicinity of the base but does not appear in this base. These notches are typically between 2 and 20 millimeters wide. The depth of these nicks varies depending on the capacity of the bottle and is usually equal to 1.5 millimeters in a 0.5 liter bottle (3 to 4 millimeters in a 1.5 liter bottle).

In one variation, the base end portion 24 of the notch contacts the base without showing any appearance in the base.

Further, it is conceivable that the base end portion 24 of the notch appears in the base.

The reinforcing rib 1 that can complement the notches in some embodiments will now be described.

These reinforcing notches 1 have an outer edge 13 that reaches the vicinity of the annular step 9 in the bottom 3 but does not reach this annular step 9 itself.

In the example shown, these ribs 1 have an inner edge 14 that reaches the vicinity of the transverse central part 11 but does not reach the transverse central part 11 itself.

In any case, it is conceivable that the inner edge 14 of the rib 1 further appears in the central portion 11 in the transverse direction.

Each rib 1 includes a bottom partition wall 15 and wings 16 and 17 on both sides of the bottom partition wall 15. The bottom partition wall 15 decreases in thickness from the outer edge 13 to the inner edge 14 of the rib. As can be seen in the figure, the curvature of the bottom partition wall 15 of the rib is not constant over the entire length of the rib in the radial direction. In the vicinity of the outer edge 13, the rib 1 forms a sharper angle on the vertical surface than in the vicinity of the inner edge 14.

Each rib 1 forms a plane of symmetry 18 in the vertical radial direction.

The rib 1 leans against the central ventilation path 19 at the center where the patch 12 protrudes downward from the rib, and the central ventilation path 19 is limited in the height direction through the transverse central portion 11.

DESCRIPTION OF SYMBOLS 1 Reinforcing rib 2 Notch 3 Hollow body bottom 4 An axis substantially perpendicular to the transverse support surface 5 A transverse support surface 6 A transverse outer edge 7 A parabolic contour 8 A direction perpendicular to a transverse support surface 9 An annular step 10 A parabolic contour 11 transverse Directional central portion 12 Patch of low crystallinity material 13 Outer edge of reinforcing rib 14 Inner edge of reinforcing rib 15 Bottom partition wall 16 Bottom partition wall side wing 17 Bottom partition wall side wing 18 Vertical radial symmetry plane 19 center The partition wall 21 at the bottom of the ventilation path 20 The side wing 22 The side wing 23
h6 Height of transverse outer edge with respect to transverse support surface
h11 Height of transverse central portion (11) with respect to transverse support surface (5)

Claims (15)

On the transverse support surface (5) and on both sides of this transverse support surface (5),
・ Transverse outer edge (6),
A hollow obtained by blowing or drawing in a preform of thermoplastic material that includes a concave inner partition with a transverse central portion (11) that includes a patch (12) of low crystallinity material that coincides with the injection point of the preform A body bottom (3) comprising a peripheral area around the transverse support surface with a notch (2), the end (23) of the notch being at the outer edge (6) of the bottom (3) The bottom of the hollow body (3), characterized in that it reaches the vicinity itself but does not reach itself, and the base end portion (24) of the notch contacts the transverse support surface (5). The hollow body bottom according to claim 1, characterized in that the notches (2) include a partition wall (20) at the bottom and both lateral wings (21, 22) and at the same time exhibit a plane of symmetry. The hollow body bottom according to claim 1, characterized in that the base end portion (24) of the notch does not appear on the transverse support surface (5). The hollow body bottom according to any one of claims 1 to 3, wherein the width of the notch is between approximately 2 and 20 millimeters. The hollow body bottom according to claim 4, characterized in that the depth of these indentations is between approximately 1 and 5 millimeters. The hollow body bottom according to any one of claims 1 to 5, characterized in that the patch (12) of low crystallinity material protrudes on the outer surface in the transverse central part (11). The outer edge (6) is disposed at a height h6 relative to the transverse support surface (5), and the transverse central portion (11) is disposed at a height h11 relative to the transverse support surface (5). The hollow body bottom according to any one of claims 1 to 6, wherein The hollow body bottom according to any one of claims 1 to 7, characterized in that it forms a rotating body around an axis (4) substantially perpendicular to the transverse support surface (5). In the vertical radial cross section between the outer edge (6) and the transverse support surface (5),
In the vicinity of the outer edge (6), substantially in the direction (8) perpendicular to the transverse support surface (5),
In the vicinity of the transverse support surface (5), substantially in contact with this transverse support surface,
The hollow body bottom according to claim 8, which has an outer shape. The hollow body bottom according to claim 9, characterized in that it has a substantially parabolic profile (7) in a vertical radial section between the outer edge (6) and the transverse support surface (5). The hollow body bottom according to claim 9 or 10, characterized in that the transverse support surface (5) has a continuous annular shape. Starting from this transverse support surface (5) and towards the axis of rotation (4), the bottom (2) first has an annular step (9) and then the transverse central part (11). The hollow body bottom according to claim 11, characterized in that it has a parabolic outline (10) connecting the annular steps (9). A plurality of reinforcing ribs (1) having an outer edge (13) reaching near the transverse support surface (5) is included, and these reinforcing ribs (1) having an inner edge (14) are arranged in the transverse central portion ( The hollow body bottom according to claim 1 or 12, characterized in that it reaches the vicinity of 11) but does not reach the central portion (11) in the transverse direction. The hollow body bottom according to claim 13, characterized in that the reinforcing rib (1) does not reach the transverse support surface (5). A preform comprising a transverse partition wall and a bottom connected to the transverse partition wall, wherein the bottom is as shown in any one of claims 1 to 14. Hollow body made by thermoplastic material of polyester such as PET, obtained by blow molding or pultrusion blow molding

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