Flat container with a curved bottom and a seat with variable width

Description

[0001] The invention relates to the field of containers obtained by blow molding or stretch blow molding from a blank (for example a preform or an intermediate container) made of plastic material such as PET (polyethylene terephthalate).

[0002] The invention relates more particularly to flat containers, that is to say, containers having a flattened cross-section, typically oval or rectangular. This type of container is particularly suited to certain applications (notably cosmetics) in which the contents have a high viscosity, and pressure on the body of the container promotes the flow of the contents.

[0003] But this type of container is not limited to cosmetic applications, and, for ergonomic reasons, it is also used in beverage packaging, the flattened section offering a better grip, as explained in international application WO 2007 / 127789 (The Coca Cola Company) or its American equivalent US 2010 / 0000963.

[0004] This advantage in terms of ergonomics is accompanied, however, by a mechanical disadvantage, namely a certain instability, due to the flattening of the container which increases the risk of tipping in an axial plane parallel to the small width of the container.

[0005] The stability of the container is inversely proportional to its ease of handling. It is a compromise between these two constraints that the solution set out in the aforementioned document WO 2007 / 127789 aims for, which proposes on the one hand to maintain the ratio W / D (where W is the major width of the container, and D its minor width) between 1.2 and 1.8, and on the other hand to equip the bottom of the container with rounded chamfers (sic) whose diameter is smaller in the minor width of the container than in its major width.

[0006] In reality, this solution only provides a partial answer to the instability problem affecting flat containers. In practice, the natural instability (due to the flat shape) of such a container is frequently compounded by instability due to shape defects on the bottom, resulting from poor blowability (by "blowability" we mean its ability to conform to the shape of the mold) due to design flaws (primarily in sizing).

[0007] Blowability problems are all the more difficult to solve on a flat container which by nature is more stretched in the direction of the greater width than in the direction of the lesser width.

[0008] A simple first solution could be to increase the blowing pressure, but manufacturers are faced with the need to control the energy consumption of the machines, forcing the blowing pressure to decrease.

[0009] A second simple solution could be to increase the blowing time (and therefore the cycle time) to promote better mold impression, but this solution also runs up against process constraints, which aim to decrease the cycle time to increase production rates.

[0010] It is therefore understandable that it is necessary to improve the shape of the containers to increase their stability while promoting blowability.

[0011] The invention aims to provide a flat container capable of fulfilling one or more (and preferably all) of the following objectives: good stability; good compromise between ergonomics and stability; good airflow; absence (or near absence) of flatness defects on the bottom.

[0012] For this purpose, a plastic container is proposed, having a flattened body and a base extending from the body at one of its lower ends, the base comprising: a peripheral base defining an annular laying plane whose contour has, along a major axis, a major dimension A and, along a minor axis perpendicular to the major axis, a minor dimension A' strictly smaller than the major dimension; a concave vault extending from the base towards a central zone; the base having, between the laying plane and the vault, an internal annular cheek substantially perpendicular to the laying plane; the base comprising a step forming a step at the junction between the laying plane and the cheek; this base having: o along the major axis, a width C such that: 0 , 03 ≤ C A ≤ 0 , 1 o along the minor axis, a width C' such that: 0 , 05 ≤ C ′ A ′ ≤ 0 , 15 .

[0013] When dimensioned in this way, this container exhibits both good rigidity at its base (for the benefit of the container's stability), particularly in the plane of the minor axis, while offering good airflow at the base.

[0014] Various features can be included, either alone or in combination: the base presents, between the laying plane and the vault, an internal annular cheek substantially perpendicular to the laying plane, this cheek extending, along the major axis, over a height D such that: 0 , 002 ≤ D A ≤ 0 , 1 The height D of the cheek is such that: 0 , 01 ≤ D A ≤ 0 , 05 The height D of the cheek is such that: D A ≅ 0 , 025 The cheek extends, along the minor axis, over a height D' such that: 0 , 002 ≤ D ′ A ′ ≤ 0 , 1 The height D' of the cheek is such that: 0 , 01 ≤ D ′ A ′ ≤ 0 , 1 The height D' of the cheek is such that: D ′ A ′ ≅ 0 , 06 The width C of the seat along the major axis is such that: C A ≅ 0 , 05 The width C' of the seat along the minor axis is such that: C ′ A ′ ≅ 0 , 08

[0015] Other objects and advantages of the invention will become apparent from the description of a preferred embodiment, given below with reference to the accompanying drawings in which: there figure 1 is a perspective view from below of a plastic container, detailing the bottom of the container in an enlarged inset; the figure 2 is a view from below of the bottom of the container of the figure 1 ; there figure 3 is a detailed cross-sectional view of the container of the figure 2 , according to section plan III-III, according to a first embodiment not in accordance with the invention; the figure 4 is a detailed cross-sectional view of the container of the figure 2 , according to section plan IV-IV, according to the first embodiment not in accordance with the invention; the figure 5 is a view similar to the figure 3 , according to a second embodiment; the figure 6 is a view similar to the figure 4 , according to the second embodiment.

[0016] On the figure 1 is represented a container 1 formed by stretch blow molding, within a mold with the imprint of the container 1, of a preform made of plastic material such as PET (polyethylene terephthalate).

[0017] The container 1 includes a body 2 which extends along a main X axis and continues, on one lower side, as a base 3, and, on an upper side, opposite the bottom 3, by a shoulder 4 itself extended by a collar 5 defining a drinking vessel.

[0018] At the junction between the body 2, at its lower end, and the bottom 3, the container 1 presents a leave 6 external connecting part having a circular arc profile with a small radius (less than or equal to 2 mm).

[0019] The bottom 3 includes a seat 7peripheral device that defines a plan 8 of continuous placement, substantially perpendicular to the main X axis of the container 1, and by which it can rest flat on a flat surface (in particular the upper surface of a table or conveyor belt, within a handling machine on a container production line).

[0020] The plan 8 The placement area is delimited transversely outwards (i.e., opposite the X-axis of the container) by a perimeter 9 externally defined internally by the leave 6.

[0021] The container 1 In cross-section (that is, perpendicular to its X-axis), it presents a flattened shape, in this case roughly oval. This shape extends to the bottom 3, particularly at the level of the plan 8 pose, the outline of which is essentially the same as the body 2in section and which, like an ellipse, presents: along a major axis (in the section plane III-III on the figure 2 , or even in the plan of the sheet on the figure 3 ), a large transverse extension A (called the large dimension), measured perpendicularly to the X-axis at the perimeter 9, and along a minor axis, perpendicular to the major axis (that is, in the IV-IV cutting plane on the figure 2 , or even in the plan of the sheet on the figure 4 ), a transverse extension A', also measured perpendicularly to the X axis at the perimeter, this small transverse extension (called the small dimension) being strictly less than the large dimension A: A ′ A < 1

[0022] The seat 7 includes a cheek 10 internal annular ring that extends axially towards the interior of the container 1 in line with the plan 8of installation, substantially perpendicular to it. According to a first embodiment illustrated on the figures 3 et 4 the seat 7 includes a leave 11 internal having a circular arc profile with a small radius (less than or equal to approximately 2 mm), which connects the plane 8 posing on the cheek 10.

[0023] According to a second embodiment illustrated on the figures 5 et 6 the seat 7 includes, instead of a connecting leave of the plan 8 posing on the cheek 10, a walk 11' forming a step at the junction between the plane 8 posing and cheek 10. This walk 11' can serve as a hollow reservoir allowing the contents to be displaced towards the inside of the container 1a possible burr resulting from the creep of material in a parting line of the mold in which the container is formed, this parting line being defined between a wall of the mold (at the impression of the body and the placement plane) and a bottom of the mold (at the impression of the arch).

[0024] The plan 8 The installation area is delimited transversely inwards (i.e., in the direction of the X-axis of the container) by a perimeter 12 internal, defined externally by the leave 11 internal (in the case of the first embodiment) or, respectively, by an internal edge of the step 11', at its junction with the cheek 10 (in the case of the second embodiment).

[0025] The bottom 3 It also includes a vault 13 concave, with the concavity facing outwards from the container 1. This vault 13 extends from the seat 7, extending from the cheek 10,up to an area 14 central part of the base defining a pin that extends axially in projection towards the interior of the container 1.

[0026] Note: C is a width of the plane 8 of installation (confused with the width of the seat) 7), measured radially along the major axis between the perimeter 12 internal and perimeter 9 external, respectively between an internal edge of the step 11', at its junction with the cheek 10, and the perimeter 9 external; This is the width of the plane 8 of pose measured radially along the minor axis; D a height of the cheek 10 (confused with the internal height of the seat) 7), measured along the major axis (i.e., in the cutting plane III on the figure 3 , or in the plan of the sheet on the figure 3 or the figure 5 ) between the plane 8 of placement and the junction of the cheek 10with the vault 13 ; From the height of the cheek 10 measured along the minor axis (i.e., in the cutting plane IV on the figure 3 , or in the plan of the sheet on the figure 4 or the figure 6 ).

[0027] The bottom 3 is designed to maximize seat stability 7 while promoting its breathability.

[0028] To that end, the seat 7 is dimensioned such that its width C varies according to its transverse extension. More precisely, the width C of the seat 7 is sized as follows: Firstly, the width C of the seat 7 along the major axis is such that: 0 , 03 ≤ C A ≤ 0 , 1 preferably with: C A ≅ 0 , 05 secondly, the width C' of the seat 7 along the minor axis is such that: 0 , 05 ≤ C ′ A ′ ≤ 0 , 15 preferably with: C′A′≅0.08

[0029] Furthermore, the width C of the seat 7 along the major axis is preferably strictly greater than its width C' along the minor axis: C > C ′

[0030] The cheek 10 is also dimensioned according to the transverse dimension of the seat 7 : Firstly, the height D of the seat measured along the major axis is such that: 0 , 002 ≤ D A ≤ 0 , 1 preferably with: 0 , 01 ≤ D A ≤ 0 , 05 and, according to a particular embodiment: D A ≅ 0 , 025 Secondly, the height D of the seat measured along the major axis is such that: 0 , 002 ≤ D ′ A ′ ≤ 0 , 1 preferably with: 0 , 01 ≤ D ′ A ′ ≤ 0 , 1 and, according to a particular embodiment: D ′ A ′ ≅ 0 , 06

[0031] This sizing helps maintain good stability of the container 1particularly in the plane of the minor axis (i.e., the smaller dimension), while maintaining good airtightness of the container in the plane of the major axis, where stretching is more difficult but where the stability of the container 1 is naturally better.

[0032] The greatest width of the plan 8 Laying the seat along its major axis contributes to good airflow. 7 in this direction, minimizing the risk of distortions (or flatness defects) appearing on the plane 8 of installation.

[0033] Furthermore, the narrowness of the seat 7 Laying it along the minor axis gives it a quasi-linear character, which reduces the risk of hyperstaticity of the base. 7 and consequently increases the stability of the container 1.

[0034] Cheek sizing 10 contributes in particular to: to improved airflow of the bottom 3in the plane of the major axis, minimizing the amount of material requiring axial stretching; resulting in improved arch rigidity 13, thanks to the variation in height of its external perimeter (at its junction with the cheek 10) ; to greater rigidity of the seat 7 along the minor axis, to the benefit of its stability in that direction.

[0035] To form such a container 1, It is preferable to use the boxing technique, in which the container 1 is blown into a mold with a side wall defining a cavity in the shape of the body 2 and a mold base mounted movable relative to the wall between a low position in which the base is away from the cavity, and a high position in which the base closes the cavity, completing the impression of the container 1.The mold bottom, initially in a lower position, was raised during the blowing process, resulting in overstretching of the material at the bottom. 3, favorable to its imprinting, particularly at the base 7.

Claims

1. Container (1) made of plastics material, having a flattened body (2) and a bottom (3) in the continuation of the body (2) at a lower end thereof, the bottom (3) comprising: - a peripheral seating surface (7) defining an annular standing plane (8), the contour of which has, along a major axis, a large dimension A and, along a minor axis perpendicular to the major axis, a small dimension A' that is strictly smaller than the large dimension, - a concave arch (13) that extends from the seating surface (7) to a central region (14); - the seating surface (7) has, between the standing plane (8) and the arch (13), an internal annular flange (10) substantially perpendicular to the standing plane (8); - the seating surface (7) comprises a step (11') forming an indentation at the join between the standing plane (8) and the flange (10); characterized in that: - the seating surface (7) has: ∘ along the major axis, a width C such that: 0.03 ≤ C A ≤ 0.1 o along the minor axis, a width C' such that: 0.05 ≤ C ′ A ′ ≤ 0.

152. Container (1) according to Claim 1, characterized in that the seating surface (7) has, between the standing plane (8) and the arch (13), an internal annular flange (10) substantially perpendicular to the standing plane (8), this flange (10) extending, along the major axis, over a height D such that: 0.002 ≤ D A ≤ 0.

13. Container (1) according to Claim 2, characterized in that the height D of the flange (10) is such that: 0.01 ≤ D A ≤ 0.

054. Container (1) according to Claim 2, characterized in that the height D of the flange (10) is such that: D A ≅ 0.0255. Container (1) according to one of Claims 2 to 4, characterized in that the flange (10) extends, along the minor axis, over a height D' such that: 0.002 ≤ D ′ A ′ ≤ 0.

16. Container (1) according to Claim 5, characterized in that the height D' of the flange (10) is such that: 0.01 ≤ D ′ A ′ ≤ 0.

17. Container (1) according to Claim 5, characterized in that the height D' of the flange (10) is such that: D ′ A ′ ≅ 0.

068. Container (1) according to one of the preceding claims, characterized in that the width C of the seating surface along the major axis is such that: C A ≅ 0.

059. Container (1) according to one of the preceding claims, characterized in that the width C' of the seating surface along the minor axis is such that: C ′ A ′ ≃ 0.0810. Container (1) according to one of the preceding claims, characterized in that the width C of the seating surface along the major axis is such that: C > C ′