FR3111123A1 - Plastic container - Google Patents

Abstract

Title: Container made of plastic material The invention relates to a container (1) made of plastic material extending along a longitudinal axis (A), and comprising:- a neck (10) having an opening;- a shoulder (11) extending axially the neck (10);- a bottom (13) having a semi-elliptical profile;- a body (12) extending between the shoulder (11) and the bottom (13), and comprising, along its axis longitudinal (A) and below the neck (10), at least one anti-rotation portion (2). Figure for abstract: Fig. 1

Description

Plastic container

The field of the invention is that of the design and manufacture of containers from plastic preforms.

The invention relates more particularly to a design of plastic containers suitable for carbonated beverages.

Conventionally, a plastic container is obtained by blow molding or stretch-blow molding of a preform within a mold in the cavity of the container.

Prior to its blowing, with or without stretching, the preform is heated until its constituent material reaches or exceeds its glass transition temperature. For example, in the case where the container is made of polyethylene terephthalate, the glass transition temperature is of the order of 70° C. and can approach 80° C., depending on the formulation of the material.

Plastic containers usually include:
- A body extending along a longitudinal axis, and of substantially cylindrical shape of revolution around the longitudinal axis;
- A bottom, which closes the body at a first end thereof;
- a shoulder, which extends in the extension of the body from a second end thereof;
- a neck surmounting the shoulder and having an opening.

According to a conventional design, the bottoms are stiffened by giving them a hollow shape defining a vault intended to resist various stresses.

These funds also define a laying plane for the containers. That is to say that a container can be placed on its bottom, in a stable manner.

For example, the bottoms may have a petaloid shape capable of withstanding the stresses exerted on the container during its manufacture, its handling, and its use. These petaloid bottoms are in particular capable of retaining their shape, and thus their ability to form a resting plane for the container, including when the product contained in the container is a carbonated drink capable of exerting pressure on the container in such a way as to deform.

Obtaining containers with the correct shape, and in particular a correctly formed hollow bottom, involves the use of preforms with sufficient material, and the use of a preform blowing pressure often greater than 20 bar.

More generally, a preform having a weight of at least 13 grams comprises enough material to form the bottom of a 330 ml bottle as defined previously. Indeed, the formation of a petaloid bottom, for example, requires a certain amount of plastic material for its realization.

The blowing pressure greater than 20 bars, meanwhile, allows the material of the preform to be correctly pressed against the bottom of the mold at the indentation of the bottom that one wishes to obtain, in particular at the end of the feet of the bottom.

During the formation of a bottom with a vault, microcracks can be generated. These microcracks are likely to propagate when the container is pressurized. Cases of breakage have even been observed in certain applications.

There are also petaloid bottoms, provided with alternating protruding feet and hollow valleys, and which form a very widespread solution for carbonated drinks. This solution makes it possible to consume less material than those using vaults. However, they have the disadvantage of being more sensitive to the problem of stress cracking. If this stress cracking is significant, then it can lead to the generation of micro cracks on the bottom which can lead to the explosion of the packaging during storage.

This phenomenon of stress cracking can be linked to several factors such as the design of the petaloid bottom, the temperature and humidity conditions present during storage, external chemical attacks (lubricants on the bottling lines), or even conditions and of parameters during the injection of the preform. This stress cracking, and the associated micro cracks are present on the amorphous part of the bottom PET, and not on the totally bi-oriented parts.

The risk of cracking (and breaking) is aggravated by the tendency of the market, in search of savings in material and reduction of polluting emissions, to impose a reduction in the weight of the preforms, and therefore in the thickness of the walls of the preforms. .

This risk is also aggravated by the increase in production rates (several tens of thousands of containers produced per hour and per machine), which forces a reduction in the individual manufacturing cycle time of the container.

This results in a reduction in the contact time of the container with the mould, and therefore less cooling of the container.

In addition, after blowing or stretch-blow molding, certain plastic containers (in particular PET, very widely used in the manufacture of containers) undergo internal stresses, due to the pressures imposed by the carbonated drinks, which can tend to deform them. importantly.

An example of unwanted deformation corresponds to a collapse of the central part of the bottom of the container. In this case, after the manufacture of the container, the concave bottom of the deformed container has a vault of lower height than expected. Indeed, due to insufficient cooling of the container, and more specifically of the lower part of the container, the concave bottom of the container deforms when it comes out of the mould.

Such a deformation can potentially limit the capacity of the container to be deposited in a stable manner on its bottom, and this deformation is amplified by the internal pressure stresses which will be applied to it after filling.

The quest for material savings and reduction of polluting emissions is nevertheless paramount.

The aim of the invention is in particular to meet this need.

More specifically, the invention aims to provide a container requiring less plastic to be manufactured, compared to containers of identical destination and capacity, while ensuring the ability of the container to be deposited on a deposit surface and to stay there.

The invention also aims to provide such a container which requires less energy to be formed compared to the containers according to the prior art.

Another object of the invention is to provide a container which is not, or only slightly, subject to the stress cracking phenomena described previously, or to the risks of cracking.

These objectives, as well as others which will appear subsequently, are achieved thanks to the invention which relates to a plastic container extending along a longitudinal axis, and comprising:
- a neck having an opening;
- a shoulder extending axially from the neck;
- a bottom having a semi-elliptical profile;
- a body extending between the shoulder and the bottom,
characterized in that it comprises, along its longitudinal axis and below the neck, at least one anti-rotation portion having, in a section perpendicular to the longitudinal axis, at least one boss protruding from the outside of the container relative to the container body.

The container according to the invention has the ability to be placed horizontally on a surface, in an essentially stable manner.

This ability to be placed horizontally compensates for the fact that this container cannot be placed vertically on its bottom, in a conventional manner.

Indeed, due to the semi-elliptical section of the bottom, the latter does not define a laying plane and does not allow the container to be placed vertically.

Thanks to the anti-rotation portion(s), the container can be set down horizontally without the risk of it rolling on a set-down surface until it falls.

The boss(es) of an anti-rotation portion allow the container, when it is placed on a horizontal surface, to be stabilized using a boss, or to roll on itself until the boss or one of the bosses is in contact with the resting surface. In this case, the container no longer moves, or tends not to move.

Thanks to its design, and in particular to the fact that the bottom does not have a complex shape (vaulted shape, petaloid, etc.), the container according to the invention can be manufactured from a preform having a lower weight compared to the preforms conventionally used to form containers capable of being held vertically on a deposit surface.

In particular, 330 ml containers according to the invention can be obtained with preforms having a weight of approximately 10 grams.

In addition, thanks to this simple shape of the bottom of the container, the blowing of the container does not need to be carried out at a pressure as high as that required to form containers according to the prior art. Indeed, it has been found, during tests, that a pressure of approximately 10 bars is sufficient to blow and correctly form the container according to the invention.

This simple shape of the bottom also simplifies obtaining a correctly formed container, little subject to the phenomena of stress cracking previously described, and particularly suitable for containing carbonated drinks.

According to an advantageous characteristic, the or each anti-rotation portion has, in a section perpendicular to the longitudinal axis, a plurality of bosses angularly spaced from each other around the longitudinal axis.

In this way, a container has the ability to more quickly reach a position of equilibrium when it is placed horizontally.

Compared to an embodiment of the container according to the invention which would have a single boss on an anti-rotation portion, this embodiment allows the container to avoid rolling over too great a distance for one of the bosses to reach contact with a resting surface of the container.

In this case, according to a preferred embodiment, for the or each anti-rotation portion, the bosses are regularly spaced from each other around the longitudinal axis.

When deposited horizontally, the container exhibits homogeneous or essentially homogeneous behavior regardless of the side face on which it is deposited.

According to a preferred design, the or each anti-rotation portion has 3 to 6 bosses around the longitudinal axis.

Such numbers of bosses (from 3 to 6) promote the anti-rotation effect of the container when it is placed on a resting surface while preventing it from rolling too much on this resting surface to reach the one of the bosses and stabilized.

According to a preferred characteristic of the container, for the or each anti-rotation portion, the bosses of said anti-rotation portion each have a point furthest from the longitudinal axis, said points being inscribed on the same circle centered on the longitudinal axis .

The bosses thus have identical heights.

The anti-rotation effect provided by the bosses then tends to be identical for each of the bosses.

This characteristic also makes it possible to promote good formation of the container during the blow molding, the material of the preform then tending to be distributed in an essentially identical manner for each of the bosses.

According to a preferred solution, the body has a main portion of substantially cylindrical shape of revolution centered on the longitudinal axis.

The container then has a form that is simple to produce and to handle.

In addition, such a container has an advantageous capacity/size ratio.

Of course, in this case, the boss or bosses project relative to the cylindrical shape of the main portion or to a projection of this cylindrical shape.

According to a second solution, the body has a main portion of substantially frustoconical shape of revolution centered on the longitudinal axis.

Such a shape is also easy to produce and to handle while having a shape benefiting from the anti-rotation effect provided by the anti-rotation portion(s).

Of course, in this case the boss(es) protrude from the frustoconical shape of the main portion or from a projection of this frustoconical shape.

According to an advantageous design of the container, it comprises at least two anti-rotation portions, the or each boss of an anti-rotation portion being angularly aligned around the longitudinal axis of the container with the or one of the bosses of another portion anti rotation.

In this way, two distant bosses along the container, and belonging to two distinct anti-rotation portions can participate simultaneously (and together, that is to say cumulatively) in the anti-rotation effect of the anti-rotation portions when the container is placed horizontally on a resting surface.

This design also makes it possible to overcome a situation in which the container does not rest completely on the resting surface, and where one of an anti-rotation portion does not touch said surface.

According to a first variant, the shoulder has the or one of the anti-rotation portions.

According to a second variant, the bottom has an upper portion, directly adjacent to the body, the upper portion of the bottom forming the or one of the anti-rotation portions.

The first and the second variant can be combined into a third variant.

According to these variants, then it is at the ends of the body that the anti-rotation portion(s) are located.

According to a preferred characteristic, the bottom is hemi-ellipsoid, and more precisely hemispherical.

The bottom is then particularly economical to produce.

Other characteristics and advantages of the invention will appear more clearly on reading the following description of various preferred embodiments of the invention, given by way of illustrative and non-limiting examples, and the appended drawings, among which:

FIG. 1 is a schematic representation according to a perspective view of a container according to the invention, the container comprising anti-rotation portions provided with boss(es), the container being oriented in such a way that the bosses are visible in protruding from the sides of the illustrated container;

Figure 2 is a schematic representation according to a side view of the container of Figure 1, oriented such that the bosses are not visible projecting from the sides of the illustrated container;

Figure 3 is a schematic representation in cross section of an anti-rotation portion according to a first embodiment;

Figure 4 is a schematic representation in cross section of an anti-rotation portion according to a second embodiment.

Referring to Figures 1 and 2, a container 1 according to the invention is shown.

Container 1 is a bottle made from a thermoplastic material such as PET (acronym for polyethylene terephthalate).

The container 1 extends along a longitudinal axis A between a neck 10 and a bottom 13.

This container 1 comprises, along the longitudinal axis A:
- neck 10;
- A shoulder 11 axially extending the neck 10;
- A body 12 axially extending the shoulder 11;
- the bottom 13 axially extending the body 12 by closing it.

The neck 10 has an opening allowing the container 1 to be filled or emptied.

Referring to Figures 1 and 2, the bottom 13 has a semi-elliptical profile.

By semi-elliptical profile, it is understood that the line describing the profile of the bottom 13 is a continuous section of an ellipse, the ellipse being a closed plane curve obtained by the intersection of a cone of revolution or a cylinder of revolution with a plane, provided that this intersects the axis of rotation of the cone or cylinder. In other words, the line is an open planar curve with a single curvature forming a concavity, or multiple curvatures with concavities facing the same side of the line.

According to a preferred characteristic, this bottom 13 is hemi-ellipsoid, and more precisely hemispherical, advantageously centered on the longitudinal axis A.

Bottom 13 includes:
- an upper part 130;
- a lower part 131.

The upper part 130 is directly in the extension of the body 12.

In other words, the upper part 130 axially extends the body 12.

The lower part 131 of the bottom 13 in turn extends the upper part 130. This lower part 131 closes the upper part 130, and thus the body 12 of the container 1.

Shoulder 11 has:
- a lower portion 111;
- an upper portion 110.

The lower portion 111 of the shoulder 11 axially extends the body 12.

The upper portion 110, which axially extends the neck 10, is located between the neck 10 and the lower portion 111 of the shoulder 11.

The upper portion 110 thus extends axially the lower portion 111 of the shoulder 11.

Still referring to Figures 1 and 2, the body 12 has, according to the embodiments shown, a single main portion.

This main portion has a substantially cylindrical shape of revolution centered on the longitudinal axis A.

In other words, the body 12 is part of a cylinder of revolution centered on the longitudinal axis A.

As detailed below and illustrated in Figures 3 and 4, the main portion of substantially cylindrical shape of revolution has an outer diameter Øm.

According to a conceivable embodiment variant not shown, the main portion of the body 12 may have a substantially frustoconical shape of revolution centered on the longitudinal axis A.

According to yet other variant embodiments not shown, the body 12 may have combinations of at least one portion of substantially cylindrical shape of revolution and at least one portion of substantially frustoconical shape of revolution.

With reference to the principle of the invention and as illustrated by Figures 1 to 4, the container 1 comprises, along its longitudinal axis A, and below the neck 10, at least one anti-rotation portion 2.

An anti-rotation portion 2 has, along a section perpendicular to the longitudinal axis A, at least one boss 20 projecting from the outside of the container 1, relative to the body 12 of the container 1.

Each boss 20 is intended to form a stop capable of limiting a movement of the container 1 on a deposit surface, when said container 1 is arranged horizontally on said surface, that is to say that the longitudinal axis A is parallel, or almost, to the deposit surface.

Due to the specific shape (semi-elliptical profile) of the bottom 13 of the container 1, this container 1 cannot be held vertically on a deposit surface, balanced on its bottom 13.

By "vertically" it is understood that the container 1 is held in such a way that the longitudinal axis A is perpendicular, or almost, to the resting plane.

Consequently, it is natural for a person to seek to deposit the container 1 horizontally on a deposit surface.

In this case, the container 1 tends to stabilize automatically, instantly and/or quickly in position on the deposit surface, thanks to at least one of the bosses 20.

As illustrated in Figure 1, and in Figures 3 to 4, the container 1 comprises several anti-rotation portions 2 each having several bosses 20 each projecting from the outside of the container 1.

Indeed, as illustrated by Figures 1 and 2, the container 1 comprises, along its longitudinal axis A, two anti-rotation portions 2.

These anti-rotation portions 2 correspond in particular to portions (or slices) of the container 1 extending over predetermined heights of the container 1 along the longitudinal axis A.

According to the present embodiments, the container 1 comprises:
- A first anti-rotation portion 2 formed by the lower portion 111 of the shoulder 11 of the container 1;
- a second anti-rotation portion 2 formed by the upper part 130 of the bottom 13 of the container 1.

Referring to Figure 1, the perspective view illustrates bosses 20 projecting from the outside of container 1, relative to body 12.

As can be seen in Figure 2, which illustrates the same container 1 but from a different angle of view, the bosses 20 are not visible on the projection of the outline of the container 1.

The projecting positioning of the bosses 20 with respect to the body 12 can be visualized in the manner described below.

Referring to Figures 1 and 2, lines G are shown. These straight lines G correspond to straight lines along each of which is inscribed a generatrix of the shape of the body 12. In other words, each straight line G defines a generatrix of the cylinder of revolution formed by the main portion of the body 12.

In Figure 2, no boss 20 is visible on the profile of the container 1, at the level of the anti-rotation portions 2.

However, according to Figure 2, the container 1 is turned and the bosses 20 are then not visible on the profile of the container 1. As can be seen in Figure 1, the bosses 20 thus extend beyond the line G .

Referring to Figures 3 and 4, each anti-rotation portion 2 has, along a section perpendicular to the longitudinal axis A, a plurality of bosses 20 angularly spaced from each other around the longitudinal axis A.

According to the present embodiments, the bosses 20 are regularly spaced from each other around the longitudinal axis A.

Advantageously, each anti-rotation portion 2 has from 3 to 6 bosses 20 around the longitudinal axis A.

According to the embodiment illustrated in Figure 3, each anti-rotation portion 2 has four bosses 20 around the longitudinal axis A. These bosses 20 are regularly spaced from each other around the longitudinal axis A.

Indeed, each boss 20 is spaced 90° from the directly adjacent bosses 20.

The section of the anti-rotation portion 2 has an intermediate shape between a circle and a square. Such a section constitutes a good compromise between a feasibility of blowing and a capacity for horizontal stabilization of the container 1.

According to the embodiment illustrated in Figure 4, each anti-rotation portion 2 has five bosses 20 distributed regularly around the longitudinal axis A.

Indeed, each boss 20 is spaced 72° from the directly adjacent bosses 20.

The section of the anti-rotation portion 2 has an intermediate shape between a circle and a pentagon. Such a section constitutes another good compromise between a feasibility of blowing and a capacity for horizontal stabilization of the container 1.

Referring to Figures 3 and 4, and for each anti-rotation portion 2, the bosses 20 each have a point 200 furthest (shown schematically) from the longitudinal axis A. These furthest points 200 are all inscribed on a same circle Cb which is centered on the longitudinal axis A.

This circle Cb has a diameter Øb which defines an overall radius of the container 1.

Between each boss 20, each anti-rotation portion 2 has a profile segment 3 tending to have a particularly low curvature, and this in particular compared to the curvature of each boss 20.

The profile segments 3 each have a point 30 closest to the longitudinal axis A.

These points closest 30 to the longitudinal axis A are all part of the same circle Cm.

According to the present embodiments, this circle Cm has a diameter equal to the diameter Øm of the cylinder of revolution formed by the body 12.

Of course, the diameter Øb of the circle Cb is strictly greater than the diameter Øm of the circle Cm. The bosses 20 thus all have the same distance from the circle Cm.

As illustrated by FIG. 2, between the bosses 20, each nearest point 30 of an anti-rotation portion 2 is located on one of the straight lines G, in alignment with a generatrix of the form ( cylindrical of revolution, tapered of revolution, etc. of the body 12, or of the body portion 12 which is directly adjacent to said anti-rotation portion 2.

Referring to Figures 1 and 2, the anti-rotation portions 2 are aligned.

Indeed, each boss 20 of an anti-rotation portion 2 is angularly aligned with respect to the longitudinal axis A with one of the bosses 20 of the other anti-rotation portion 2.

In this way, two distant bosses 20 can participate simultaneously in the anti-rotation effect of the container 1 on a deposit surface of the container 1.

More generally, the following design rules can be applied to obtain the container 1 according to the invention:

In particular, the ratio between Øb and Øm is such that: 85% ≤ Øm / Øb ≤ 98%.

In addition, and with reference to Figures 3 and 4, and according to a cross section of an anti-rotation portion 2, each boss 20 forms a curve falling within a circle Cx with a second radius, called boss radius Rb, with : 0 ≤ Rb ≤ Øb / 2.4.

If Rb is equal to 0, then the anti-rotation effect is the most marked, the boss then forming a right angle, however the container 1 may then be subject to deformations, due to the internal pressure, at the level of the portion anti-rotation 2.

If Rb is equal to Øb / 2.4 , then the anti-rotation effect is effective but not very marked. Beyond this value, the anti-rotation effect is no longer sufficiently effective. However, this value makes it possible to obtain a container that is not subject to deformations caused by the internal pressure at the level of the anti-rotation portion 2.

The container 1 according to the invention is adapted to contain a carbonated drink. Indeed, the container 1 has a shape that is particularly suitable for resisting internal pressure, in particular thanks to the hemispherical bottom compared to conventional vaulted bottoms.

In addition, tests have demonstrated the ability of such a 330 ml container to be correctly formed from a preform weighing approximately 10 grams, and with blowing or stretching/blowing carried out at a blowing pressure of 10 bar.

Claims (11)

Plastic container (1) extending along a longitudinal axis (A), and comprising:
- a neck (10) having an opening;
- a shoulder (11) axially extending the neck (10);
- a bottom (13) having a semi-elliptical profile;
- a body (12) extending between the shoulder (11) and the bottom (13),
characterized in that it comprises, along its longitudinal axis (A) and below the neck (10), at least one anti-rotation portion (2) having, in a section perpendicular to the longitudinal axis (A), at least one boss (20) protruding from the outside of the container (1) with respect to the body (12) of the container (1). Container (1) according to the preceding claim, characterized in that the or each anti-rotation portion (2) has, in a section perpendicular to the longitudinal axis (A), a plurality of bosses (20) angularly spaced from each other around the longitudinal axis (A). Container (1) according to the preceding claim, characterized in that, for the or each anti-rotation portion (2), the bosses (20) are regularly spaced from each other around the longitudinal axis (A). Container (1) according to either of Claims 2 and 3, characterized in that the or each anti-rotation portion (2) has 3 to 6 bosses (20) around the longitudinal axis (A). Container (1) according to any one of Claims 2 to 4, characterized in that, for the or each anti-rotation portion (2), the bosses (20) of the said anti-rotation portion (2) each have a point remote (200) from the longitudinal axis (A), said points being inscribed on the same circle (Cb) centered on the longitudinal axis (A). Container (1) according to any one of the preceding claims, characterized in that the body (12) has a main portion of substantially cylindrical shape of revolution centered on the longitudinal axis (A). Container (1) according to any one of Claims 2 to 5, characterized in that the body (12) has a main portion of substantially frustoconical shape of revolution centered on the longitudinal axis (A). Container (1) according to any one of the preceding claims, characterized in that it comprises at least two anti-rotation portions (2), the or each boss (20) of an anti-rotation portion (2) being aligned angularly around of the longitudinal axis (A) of the container (1) with the or one of the bosses (20) of another anti-rotation portion (2). Container (1) according to any one of the preceding claims, characterized in that the shoulder (11) has the or one of the anti-rotation portions (2). Container (1) according to any one of the preceding claims, characterized in that the bottom (13) has an upper part (130), directly adjacent to the body (12), the upper part (130) of the bottom (13) forming the or one of the anti-rotation portions (2). Container (1) according to any one of the preceding claims, characterized in that the bottom (13) is hemi-ellipsoid, and more precisely hemispherical.