Container having a reinforced bottom and mould bottom for producing such a container

Abstract

The present invention relates to a plastics container (1) provided with a body (2) and a bottom (3) extending from a lower end of the body (2), and a push-up (7) which extends from a central area (8) to a heel (4), the heel (4) rising back up on a wall (6) connecting to the wall of the body (2) of the container (1), the bottom (3) comprising at least one central raised portion (9) having a generally frustoconical or cylindrical side wall, the push-up (7) extending from the central raised portion (9) to the heel (4), and the push-up (7) comprising at least three main grooves (11); the container (1) is characterised in that the body (2) has a substantially circular cross-section and in that, between the main grooves (11), the push-up (7) radially comprises at least three sections (7a, 7b, 7c), wherein a first section (7a) extends from the central raised portion (9) up to a diameter ΦD, the push-up (7) having a concave profile in this first section (7a) and the concavity being oriented towards the base plane (5); a second section (7b) extends from the diameter ΦD up to a diameter ΦC, which is greater than ΦD, the push-up (7) having a convex or straight profile in this second section (7b) in accordance with a first radius of curvature; and a third section (7c) extends from the diameter ΦC up to a diameter ΦA, which is greater than the diameter ΦC, the push-up (7) having a convex or straight profile in this third section (7c) in accordance with a second radius of curvature.

Description

Container with a reinforced base and mold base for manufacturing such a container

[0001] The present invention relates to the field of containers, in particular bottles or pots, manufactured by blow molding or stretch blow molding from blanks made of plastic material such as polyethylene terephthalate (PET) and more particularly from blanks obtained in whole or in part from recycled polyethylene terephthalate (rPET). State of the art

[0002] A container classically comprises a body delimiting the overall volume of the container, extended, at an upper end of the container, by a neck, through which the container is filled and emptied, and, at a lower end, by a bottom which closes the container.

[0003] The base must be able to withstand, without significant deformation, at least the hydrostatic pressure of the liquid column above it. There are many different base shapes, depending on the application. For example, for carbonated beverages (typically sodas), the bases are generally petal-shaped, comprising alternating hemispherical valleys and protruding feet, the ends of which form a base for the container. Such a base is described in document FR2959214, among others.

[0004] Document FR2959214 describes a thermoplastic container obtained by blow molding or blow-molding from a blank. This container comprises a petal-shaped base with projecting feet, separated by recessed valleys extending radially from a central area of ​​the base. Each foot has two sides, each bordering a valley laterally. Each foot has a side panel on each of its sides that projects laterally on the valley side.

[0005] The petaloid base appears as a relatively successful solution exhibiting good resistance to high internal pressures in the container (thanks to the hemispherical shape of the valleys).

[0006] However, the petal-like base requires a significant amount of material (a total weight of approximately 18 to 23 g for a 0.5 L container), as well as a relatively high blowing pressure, to ensure proper molding of the hooves and valleys. These constraints appear justified, however, by the relatively high price at which the products are sold.

[0007] Petaloid bases, however, are unsuitable for applications involving still liquids (typically drinking water), where blowing pressure and the amount of material used (currently around 10 g for a 0.5 L container) are minimized. Furthermore, these petaloid bases are less stable on production line conveyors; a falling bottle with a petaloid base could cause the production line to stop.

[0008] A base with a simple concave arch cannot withstand a low pressure, on the order of 1 bar, inside the bottle without significant deformation. It has therefore been proposed to equip the base with radial ribs, designed to reinforce it and allow it to better resist deformations induced by pressure.

[0009] However, for certain applications involving still liquids sensitive to oxidation (particularly fruit juices, but also some still waters), it is becoming common practice to remove the air above the liquid and replace it with an inert gas (typically nitrogen). In practice, this operation, commonly called liquid inerting, can be carried out by pouring a drop of liquefied inert gas onto the surface of the liquid, immediately before sealing the container. This operation, known as liquid inerting (nitrogen inerting in the case of nitrogen), induces overpressure within the container. Even if seemingly slight (up to 1 bar), this overpressure is sufficient to significantly increase the stresses exerted on the bottom. This inerting operation is most often performed using a process called nitrogen gas inerting, which consists of introducing nitrogen gas into the container after it has been filled and before it is sealed.This gaseous inerting operation is the most commonly used inerting method and has the advantage of not pressurizing the container.

[0010] Furthermore, the blow molding process typically involves placing a blank, such as a preform preheated to a temperature above the material's glass transition temperature, into a mold shaped to the container's cavity, and then injecting a pressurized fluid (particularly a gas such as air) into the blank. The blow molding process may be supplemented by pre-drawing the blank using a sliding rod.

[0011] The dual molecular orientation that the material undergoes during blowing (axial and radial, respectively parallel and perpendicular to the general axis of the container) gives the container a certain structural rigidity.

[0012] However, the market-driven reduction in the amount of material used to manufacture containers leads manufacturers to resort to manufacturing or shaping techniques to increase the rigidity of their containers, as bi-orientation proves insufficient. As a result, two containers of the same weight do not necessarily have the same mechanical performance (strength, rigidity).

[0013] Furthermore, it is also known to stiffen the base using radial grooves. This is notably the case in documents FR2753435, FR2883550 and FR2926034.

[0014] Document FR2753435 describes a container, such as a bottle, made of plastic, obtained by injection molding followed by stretching / blowing of a preform. The base of the container has reinforcing grooves that open at the junction between the base and the wall or extend slightly onto the wall. The other end of these grooves is at the theoretical extreme limit of the unstretched central portion of the base of the container. In this way, the grooves have an optimal length without ever ending in unstretched, and therefore amorphous, material, and the base has increased resistance to creep and other stresses.

[0015] The base of this container maintains its structural integrity without tipping over as long as the volume and / or pressure conditions inside the container are normal. However, under extreme conditions, the base tends to collapse, even tipping over. For example, when the container is stored in high temperatures, typically when palletized outdoors in direct sunlight, the temperature of the contents can reach or exceed 50°C, and the pressure increase caused by the expansion of the contents can exceed the threshold at which the base tips over. The container then becomes unstable, with a high risk of the entire pallet collapsing.

[0016] Document FR2883550 describes a container, such as a bottle, made of thermoplastic material such as PET, manufactured by blow molding or stretch blow molding of a heated preform. The container has a base that is domed in the general shape of a spherical cap with its concavity facing outwards and defining an annular base. The base has reinforcing indentations projecting inwards and radiating around a central recess or chimney. These indentations are generally trapezoidal in shape with their shorter side located towards the center of the base. The indentations have respective arches that form domed trapezoidal sectors with their concavity facing inwards and extend from the base to the central recess, connecting to it in the immediate vicinity of the upper end of the central recess.

[0017] We also know of document FR2926034 which discloses a mold base for a mold for manufacturing, by blow molding or stretch blow molding, containers, in particular bottles, from preforms in thermoplastic material, such as PET, said containers having a body and a base comprising a peripheral seat, shaped in a ring, internally connected to a central area forming an arch made up of a plurality of radiating impressions alternating with a quality of radiating protrusions, which are distributed angularly in an equidistant manner around a central axis of said base of container.The mold base comprises, for molding the central zone of the container base, several radiating projecting branches distributed angularly and equidistantly, extending approximately radially from the axis of the mold base; a central trunk having a lateral wall to which the branches are connected; and intervals forming segments of angular sectors regularly separating the branches from one another. Furthermore, each radiating projecting branch has an upper portion in the form of an inclined platform sloping down from the center towards the periphery with at least two points of inflection in the curve.

[0018] In theory, it would be possible to create deep recesses in the bottom (particularly a deep vault) to increase its mechanical strength. However, this design trick, however effective, requires both additional material, incompatible with the aforementioned weight reduction requirements, and high blowing pressure, incompatible with energy-saving requirements, which, on the contrary, necessitate a reduction in the blowing pressure required to form the container.

[0019] There is therefore a need for a container whose mechanical performance is improved with equivalent blowability (i.e. the container's ability to be formed by blowing), whose optimized bottom shape provides a good compromise between blowability and rigidity, including for containers made from recycled PET, known as rPET, which has different mechanical properties than PET, whose bottom offers good resistance to turning over, and which, under extreme conditions of pressure and / or internal volume, can remain stable and whose manufacturing rate is higher without the appearance of undulations on the base. Disclosure of the invention

[0020] One of the aims of the invention is therefore to remedy all or part of these disadvantages by proposing a container of simple and inexpensive design, obtained from recycled PET known as rPET, exhibiting good resistance to the collapse of the bottom arch, requiring only a minimum of thermoplastic material and easy to conform correctly under the usual conditions of blow molding or stretch blow molding of containers intended for flat liquids.

[0021] To this end, and in accordance with the invention, a plastic container is proposed having a body and a base extending from a lower end of the body, said body comprising at its upper end a shoulder and a neck, and the base comprising at least one peripheral heel defining a seat, and an arch extending from a central area to said heel, said heel rising onto a connecting wall with the wall of the container body, said base comprising at least one central pin having a generally frustoconical or cylindrical lateral wall of revolution about the longitudinal X axis of the container and whose concavity is oriented towards the seat, said arch extending from said central pin to said heel, and the arch comprising at least three so-called main grooves extending radially from the central pin to the connecting wall,the concavity of said main grooves being oriented towards the seating plane and said main grooves being angularly distributed around said central pin, and said intermediate reinforcing grooves which extend locally astride the seating between two main grooves, said vessel having a vertical longitudinal axis of symmetry, characterized in that the body has a substantially circular cross-section and in that, between the main grooves, said vault has radially at least three sections, a first section extending from the central pin to a diameter ΦD, said vault having a concave profile in this first section, the concavity being oriented towards the seating plane, a second section extending from said diameter ΦD to a diameter ΦC greater than ΦD, said vault having a convex or rectilinear profile in this second section along a first radius of curvature,and a third section extending from said diameter ΦC to a diameter ΦA greater than diameter ΦC, said vault having a convex or rectilinear profile in this third section along a second radius of curvature.

[0022] Preferably, the second radius of curvature of the third convex section of the vault is greater than the first radius of curvature of the second convex section of the vault.

[0023] Furthermore, the average slope of the third section of the vault is between 2° and 8° relative to the plane of the base.

[0024] Preferably, the said average slope of the third section of the vault is 5° relative to the plane of the base.

[0025] Furthermore, the diameter ΦA corresponding to the distal end of the third section of the vault is between 70% and 80% of the diameter ΦB of the body of the container.

[0026] Preferably, the diameter ΦA corresponding to the distal end of the third section of the vault is equal to 75% of the diameter ΦB of the body of the container.

[0027] The said diameter ΦA corresponding to the distal end of the third section of the vault is equal to the diameter ΦA of the base of the container.

[0028] Furthermore, the diameter ΦD corresponding to the distal end of the first section of the vault, and corresponding to the proximal end of the second section of the vault, is between 50% and 60% of the diameter ΦA corresponding to the distal end of the third section of the vault.

[0029] Preferably, the diameter ΦD corresponding to the distal end of the first section of the vault, and corresponding to the proximal end of the second section of the vault, is equal to 55% of the diameter ΦA corresponding to the distal end of the third section of the vault.

[0030] Furthermore, the diameter ΦC corresponding to the distal end of the second section of the vault, and corresponding to the proximal end of the third section of the vault, is between 70% and 85% of the diameter ΦA corresponding to the distal end of the third section of the vault.

[0031] Preferably, the diameter ΦC corresponding to the distal end of the second section of the vault, and corresponding to the proximal end of the third section of the vault, is equal to 76% of the diameter ΦA corresponding to the distal end of the third section of the vault.

[0032] In addition, the Gv guard of the vault, that is to say the height separating the lower end of the central pin and the ground plane, is between 7% and 15% of the diameter ΦA and, preferably, the Gv guard of the vault is equal to 10% of the diameter ΦA.

[0033] Furthermore, the clearance Gp of the central pin, that is to say the height separating the upper end of the central pin and the seating plane, is between 15% and 25% of the diameter ΦA and, preferably, the clearance Gp of the central pin is equal to 22% of the diameter ΦA.

[0034] Furthermore, the diameter ΦP of the bottom of the central pin is between 12% and 22% of the diameter ΦA and, preferably, the diameter ΦP of the bottom of the central pin is equal to 18% of the diameter ΦA.

[0035] Preferably, the central pawn is composed of at least three consecutive rays from its base to the vault.

[0036] Furthermore, the height H of the connecting wall, said connecting wall extending from the base to the lower end of the body of the container, is between 25% and 40% of the diameter ΦA and, preferably, the height H of the connecting wall is equal to 32% of the diameter ΦA.

[0037] Furthermore, each main groove extends to a height h1 of the connecting wall, said height h1 being between 70% and 95% of the height H and, preferably, each main groove extends to a height h1 of the connecting wall, said height h1 being equal to 80% of the height H.

[0038] In addition, the depth e11 of each main groove, at the level of the connecting wall, is between 20% and 60% of the value of the Gv guard of the vault and, preferably, the depth e11 of each main groove, at the level of the connecting wall, is equal to 40% of the value of the Gv guard of the vault.

[0039] Furthermore, the maximum depth e12 of each main groove, at the level of the second section of the vault, is between 30% and 70% of the value of the Gv guard of the vault and, preferably, the maximum depth e12 of each main groove, at the level of the second section of the vault, is equal to 50% of the value of the Gv guard of the vault.

[0040] In addition, the depth e13 of each main groove, at the level of the first section of the vault, is between 30% and 70% of the value of the Gv guard of the vault and, preferably, the depth e13 of each main groove, at the level of the first section of the vault, is equal to 50% of the value of the Gv guard of the vault.

[0041] According to another characteristic, the width l11 of each main groove, at the level of the depth e11 of each main groove, i.e. at the level of the connecting wall, is between 90% and 170% of the value of said depth e11 and, preferably, the width l11 of each main groove, at the level of the depth e11 of each main groove, i.e. at the level of the connecting wall, is equal to 135% of the value of said depth e11.

[0042] Furthermore, the width l13 of each main groove, at the level of the depth e13 of each main groove, i.e. at the level of the first section of the vault, is between 80% and 160% of the value of said depth e13 and, preferably, the width l13 of each main groove, at the level of the depth e13 of each main groove, i.e. at the level of the first section of the vault, is equal to 123% of the value of said depth e13.

[0043] In addition, each reinforcing intermediate groove extends to a height h2 of the connecting wall, said height h2 being between 70% and 95% of the height H of the connecting wall and, preferably, each reinforcing intermediate groove extends to a height h2 of the connecting wall, said height h2 being equal to 80% of the height H of the connecting wall.

[0044] Advantageously, the proximal end of each intercalary groove is positioned close to the diameter ΦC.

[0045] Furthermore, the maximum depth e2 of each intermediate reinforcing groove is between 15% and 40% of the value of the Gv guard of the vault and, preferably, the maximum depth e2 of each intermediate reinforcing groove is equal to 25% of the value of the Gv guard of the vault.

[0046] Furthermore, the width l2 of each reinforcing intermediate groove, at the maximum depth e2 of each reinforcing intermediate groove, is between 60% and 100% of the value of said maximum depth e2 and, preferably, the width l2 of each reinforcing intermediate groove, at the maximum depth e2 of each reinforcing intermediate groove, is equal to 76% of the value of said maximum depth e2.

[0047] Preferably, said container according to the invention comprises a total number of main grooves and intermediate reinforcing grooves of between 6 and 16.

[0048] Another object of the invention relates to a mold base for the manufacture of a container from a plastic preform, said mold base being able to be mounted at one end of a mold comprising two walls movable relative to each other and intended to form the body of the container, said mold base comprising at least a first annular part intended to form at least in part the heel, i.e. the seating surface, a second dome-shaped part intended to come into contact with an amorphous central zone of the preform to form the arch, remarkable in that said second part is arranged so as to produce a container comprising a base according to the invention.

[0049] Other advantages and features will become clearer from the following description of several embodiments, given by way of non-limiting examples, of the container and the mold base for manufacturing said container according to the invention, with reference to the attached drawings in which:

[0050] is a perspective view from below of a plastic container according to the invention,

[0051] is a perspective view of the bottom of the container according to the invention,

[0052] is a view from below of the bottom of the container according to the invention,

[0053] is a perspective view of the interior of the bottom of the container according to the invention,

[0054] is a diametrical cross-sectional view of the bottom of the container according to the invention,

[0055] is an exploded perspective view of a mold, including a mold base, for the manufacture of a container according to the invention. Method of embodiment of the invention

[0056] In the following description of the container and the mold base for obtaining said container according to the invention, the same numerical references designate the same elements. Furthermore, the different views are not necessarily drawn to scale.

[0057] With reference to Figures 1 to 4, the container 1 according to the invention is a bottle, intended for example to contain a so-called still liquid such as still water. It is made of PET and / or rPET by extrusion blow molding or injection blow molding of its constituent material.

[0058] It is indeed to this type of container that the invention preferentially applies. However, it is quite clear that said container 1 may be made of any other thermoplastic material known per se or of a mixture of various materials without departing from the scope of the invention.

[0059] The said container 1 usually comprises a body 2 forming a cylindrical wall and extending from a bottom 3, surmounted by a shoulder, ending in a neck, terminated by a threaded neck or adapted in any other way to receive a stopper, the shoulder, the neck, the neck and the stopper not being shown in the figures.

[0060] With reference to Figures 1 to 5, the base 3 comprises a peripheral heel 4 terminating in a support 5, also called a base, perpendicular to the longitudinal axis of the container 1. This support 5 defines the lower end of the container 1 and allows the container 1 to be placed vertically on a flat surface. Furthermore, this heel 4 extends up a wall 6, called a connecting wall, to the wall of the body 2 of the container 1.

[0061] Furthermore, the base 3 also includes a concave vault 7, in the form of a substantially spherical dome with its concavity facing outwards from the container 1 in the absence of constraint, i.e., in the absence of contents in the container 1. The vault 7 extends from a central zone 8 to said heel 4, said heel 4 rising up onto the connecting wall 6 with the wall of the body 2 of the container 1. Said central zone 8 having a central pin 9 projecting towards the interior of the container 1 having a generally frustoconical or cylindrical lateral wall of revolution around the longitudinal axis of the container 1 and whose concavity is oriented towards the base 5, with in its center an amorphous pellet 10 which corresponds to the injection zone of the material constituting the preform used to make the container and can fulfill a centering function during the blow forming of the container 1.

[0062] Furthermore, said vault 7 has several main grooves 11 extending radially from the central pin 9 to the connecting wall 6, the concavity of said main grooves 11 being oriented towards the bedding plane 5 and said main grooves 11 being angularly distributed around said central pin 9, and intercalary reinforcing grooves 12 which extend locally astride the bedding 5 between two main grooves 11.

[0063] In this particular embodiment, said vault 7 comprises 6 main grooves 11 and 6 intermediate grooves 12; However, the bottom 3 of the container 1 according to the invention may comprise a total number of main grooves 11 and intermediate grooves 12 of reinforcement between 6 and 16 without departing from the scope of the invention.

[0064] Furthermore, in this example of embodiment, said container 1 having a vertical longitudinal axis of symmetry and the body 2 has a substantially circular cross-section of diameter noted ΦD.

[0065] With reference to the, between the main grooves 11, said vault 7 has radially, at least three sections, a first section 7a extending from the central pin 9 to a diameter ΦD, said vault 7 having a concave profile in this first section 7a, the concavity being oriented towards the ground plane, a second section 7b extending from said diameter ΦD to a diameter ΦC greater than ΦD, said vault 7 having a convex or rectilinear profile in this second section 7b according to a first radius of curvature, and a third section 7c extending from said diameter ΦC to a diameter ΦA greater than the diameter ΦC, said vault 7 having a convex or rectilinear profile in this third section 7c according to a second radius of curvature.

[0066] Preferably, the second radius of curvature of the third convex section 7c of vault 7 is greater than the first radius of curvature of the second convex section 7b of vault 7.

[0067] Furthermore, the average slope of the third section 7c of vault 7 is between 2° and 8° with respect to the plane of the base 5. Preferably, said average slope of the third section 7c of vault 7 is 5° with respect to the plane of the base.

[0068] Furthermore, the diameter ΦA corresponding to the distal end of the third section 7c of the vault 7 is between 70% and 80% of the diameter ΦB of the body 2 of the container 1.

[0069] Preferably, the diameter ΦA corresponding to the distal end of the third section 7c of the vault is equal to 75% of the diameter ΦB of the body 2 of the container 1.

[0070] It will be observed that, in this particular example of realization, the said diameter ΦA corresponding to the distal end of the third section 7c of the vault 8 is equal to the diameter ΦA of the base 5 of the vessel 1.

[0071] Furthermore, the diameter ΦD corresponding to the distal end of the first section 7a of vault 7, and corresponding to the proximal end of the second section 7b of vault 7, is between 50% and 60% of the diameter ΦA corresponding to the distal end of the third section 7c of vault 7.

[0072] Preferably, the diameter ΦD corresponding to the distal end of the first section 7a of vault 7, and corresponding to the proximal end of the second section 7b of vault 7, is equal to 55% of the diameter ΦA corresponding to the distal end of the third section 7c of vault 7.

[0073] Furthermore, the diameter ΦC corresponding to the distal end of the second section 7b of vault 7, and corresponding to the proximal end of the third section 7c of vault 7, is between 70% and 85% of the diameter ΦA corresponding to the distal end of the third section 7c of vault 7.

[0074] Preferably, the diameter ΦC corresponding to the distal end of the second section 7b of the vault 7, and corresponding to the proximal end of the third section 7c of the vault, is equal to 76% of the diameter ΦA corresponding to the distal end of the third section 7c of the vault 7.

[0075] Furthermore, the Gv guard of vault 7, that is to say the height separating the lower end of the central pin 9 and the ground plane 5, is between 7% and 15% of the diameter ΦA and, preferably, the Gv guard of vault 7 is equal to 10% of the diameter ΦA.

[0076] Furthermore, the clearance Gp of the central pin 9, that is to say the height separating the upper end of the central pin 9 and the seating plane 5, is between 15% and 25% of the diameter ΦA and, preferably, the clearance Gp of the central pin 9 is equal to 22% of the diameter ΦA.

[0077] Furthermore, the diameter ΦP of the bottom of the central pin 9 is between 12% and 22% of the diameter ΦA and, preferably, the diameter ΦP of the bottom of the central pin 9 is equal to 18% of the diameter ΦA.

[0078] Preferably, said central pin 9 is composed of at least three consecutive rays from its base to the vault 7; However, said central pin may have another shape such as a truncated cone or substantially hemispherical shape without going out of the scope of the invention.

[0079] Furthermore, the height H of the connecting wall 6, said connecting wall 6 extending from the base 5 to the lower end of the body 2 of the container 1, is between 25% and 40% of the diameter ΦA and, preferably, the height H of the connecting wall 6 is equal to 32% of the diameter ΦA.

[0080] Furthermore, each main groove 11 extends to a height h1 of the connecting wall 6, said height h1 being between 70% and 95% of the height H and, preferably, each main groove 11 extends to a height h1 of the connecting wall 6, said height h1 being equal to 80% of the height H.

[0081] Furthermore, the depth e11 of each main groove 11, at the connecting wall 6, is between 20% and 60% of the value of the Gv guard of the vault 7 and, preferably, the depth e11 of each main groove 11, at the connecting wall 6, is equal to 40% of the value of the Gv guard of the vault 7.

[0082] Furthermore, the maximum depth e12 of each main groove 11, at the level of the second section 7b of the vault 7, is between 30% and 70% of the value of the guard Gv of the vault 7 and, preferably, the maximum depth e12 of each main groove 11, at the level of the second section 7b of the vault 7, is equal to 50% of the value of the guard Gv of the vault 7.

[0083] Furthermore, the depth e13 of each main groove 11, at the level of the first section 7a of the vault 7, is between 30% and 70% of the value of the guard Gv of the vault 7 and, preferably, the depth e13 of each main groove 11, at the level of the first section 7a of the vault 7, is equal to 50% of the value of the guard Gv of the vault 7.

[0084] According to another characteristic, the width l11 of each main groove 11, at the level of the depth e11 of each main groove 11, i.e. at the level of the connecting wall 6, is between 90% and 170% of the value of said depth e11 and, preferably, the width l11 of each main groove 11, at the level of the depth e11 of each main groove 11, i.e. at the level of the connecting wall 6, is equal to 135% of the value of said depth e11.

[0085] Furthermore, the width l13 of each main groove 11, at the level of the depth e13 of each main groove 11, i.e. at the level of the first section 7a of the vault, is between 80% and 160% of the value of said depth e13 and, preferably, the width l13 of each main groove 11, at the level of the depth e13 of each main groove 11, i.e. at the level of the first section 7a of the vault 7, is equal to 123% of the value of said depth e13.

[0086] Furthermore, each intermediate reinforcing groove 12 extends up to a height h2 of the connecting wall 6, said height h2 being between 70% and 95% of the height H of the connecting wall 6 and, preferably, each intermediate reinforcing groove 12 extends up to a height h2 of the connecting wall 6, said height h2 being equal to 80% of the height H of the connecting wall 6.

[0087] Advantageously, the proximal end of each reinforcing intercalary groove 12 is positioned close to the diameter ΦC described previously.

[0088] Furthermore, the maximum depth e2 of each intermediate reinforcement groove 12 is between 15% and 40% of the value of the Gv guard of the vault 7 and, preferably, the maximum depth e2 of each intermediate reinforcement groove 12 is equal to 25% of the value of the Gv guard of the vault 7.

[0089] Furthermore, the width l2 of each reinforcing intermediate groove 12, at the level of the maximum depth e2 of each reinforcing intermediate groove 12, is between 60% and 100% of the value of said maximum depth e2 and, preferably, the width l2 of each reinforcing intermediate groove 12, at the level of the maximum depth e2 of each reinforcing intermediate groove 12, is equal to 76% of the value of said maximum depth e2.

[0090] With reference to the, a molding unit 19 according to the invention is described for forming, from a blank, usually typically a preform, a container according to the invention, such as a bottle or a can, according to the invention.

[0091] The molding unit 19, referred to in the figure, comprises a mold 20 having a lateral wall 21 that defines a cavity 22 in the shape of a portion of the container. The mold 20 further comprises a base 23 in the shape of the base of the container, the mold 20 being made of metal, for example, steel or aluminum (this term also covering aluminum alloys). The cavity 22, and ultimately the container 20, extends along a principal axis X that defines a vertical direction. Any plane perpendicular to the principal axis X is said to be horizontal.According to an embodiment illustrated in the drawings, the side wall 21 comprises two half-molds 20A, 20B, each defining a half-imprint 24A, 24B of the body of the container, and mounted in rotation relative to each other around a common axis formed by a hinge, not shown in the figures, between an open position, in which the half-molds 20A, 20B are angularly separated from each other and the bottom of the mold 23 is lowered relative to the half-molds 20A, 20B to allow the introduction of the blank and the evacuation of the formed container, and a closed position, in which the half-molds 20A, 20B are applied against each other and enclose the bottom of the mold 23 between them, thus forming the cavity 22 and defining the imprint of the container to be formed. The said mold base 23 is suitable for being mounted movably in the mold 20 comprising two walls movable relative to each other and intended to form the body of the container.

[0092] Thus, said mold base 23 comprises at least a first annular part intended to form at least in part the heel, i.e. the seating plane, a second dome-shaped part intended to come into contact with an amorphous central zone of the preform to form the vault, said second part being arranged so as to produce a container comprising a base according to the invention as described above.

[0093] Finally, it is quite clear that the examples we have just given are only particular illustrations and in no way limiting as to the fields of application of the invention.

Claims

A plastic container (1) having a body (2) and a base (3) extending from a lower end of the body (2), said body (2) having at its upper end a shoulder and a neck, and the base (3) having at least one peripheral heel (4) defining a base (5), and an arch (7) extending from a central zone (8) to said heel (4), said heel (4) extending up a connecting wall (6) with the wall of the body (2) of the container (1), said base (3) having at least one central stud (9) having a lateral wall that is generally frustoconical or cylindrical of revolution about the longitudinal axis X of the container (1) and whose concavity is oriented towards the base (5), said arch (7) extending from said central stud (9) to said heel (4), and the arch (7) having at least three so-called main grooves (11) extending radially from the central stud (9) up to the connecting wall (6),the concavity of said main grooves (11) being oriented towards the seat plane (5) and said main grooves (11) being angularly distributed around said central pin (9), and said intermediate reinforcing grooves (12) which extend locally astride the seat (5) between two main grooves (11), said vessel (1) having a vertical longitudinal axis of symmetry, characterized in that the body (2) has a substantially circular cross-section and in that, between the main grooves (11), said vault (7) radially comprises at least three sections (7a, 7b, 7c), a first section (7a) extending from the central pin (9) to a diameter ΦD, said vault (7) having a concave profile in this first section (7a), the concavity being oriented towards the seat plane (5), a second section (7b) extending from said diameter ΦD up to a diameter ΦC greater than ΦD,said vault (7) having a convex or rectilinear profile in this second section (7b) along a first radius of curvature, and a third section (7c) extending from said diameter ΦC to a diameter ΦA greater than diameter ΦC, said vault (7) having a convex or rectilinear profile in this third section (7c) along a second radius of curvature. Container (1) according to claim 1 characterized in that the second radius of curvature of the third convex section (7c) of the vault (7) is greater than the first radius of curvature of the second convex section (7b) of the vault (7). Container (1) according to any one of claims 1 or 2 characterized in that the average slope of the third section (7c) of the vault (7) is between 2° and 8° with respect to the plane of the base (5). Container (1) according to claim 3 characterized in that the average slope of the third section (7c) of the vault is 5° with respect to the plane of the base (5). Container (1) according to any one of claims 1 to 4 characterized in that the diameter ΦA corresponding to the distal end of the third section (7c) of the vault (7) is between 70% and 80% of the diameter ΦB of the body (2) of the container (1). Container (1) according to claim 5 characterized in that the diameter ΦA corresponding to the distal end of the third section (7c) of the vault (7) is equal to 75% of the diameter ΦB of the body (2) of the container (1). Container (1) according to any one of claims 5 or 6 characterized in that the diameter ΦD corresponding to the distal end of the first section (7a) of the vault (7), and corresponding to the proximal end of the second section (7b) of the vault (7), is between 50% and 60% of the diameter ΦA corresponding to the distal end of the third section (7c) of the vault (7). Container (1) according to claim 7 characterized in that the diameter ΦD corresponding to the distal end of the first section (7a) of the vault (7), and corresponding to the proximal end of the second section (7b) of the vault (7), is equal to 55% of the diameter ΦA corresponding to the distal end of the third section (7c) of the vault (7). Container (1) according to any one of claims 5 to 8 characterized in that the diameter ΦC corresponding to the distal end of the second section (7b) of the vault (7), and corresponding to the proximal end of the third section (7c) of the vault (7), is between 70% and 85% of the diameter ΦA corresponding to the distal end of the third section (7c) of the vault (7). Container (1) according to claim 9 characterized in that the diameter ΦC corresponding to the distal end of the second section (7b) of the vault (7), and corresponding to the proximal end of the third section (7c) of the vault (7), is equal to 76% of the diameter ΦA corresponding to the distal end of the third section (7c) of the vault (7). Container (1) according to any one of claims 1 to 10 characterized in that the guard Gv of the vault (7), that is to say the height separating the lower end of the central pin (9) and the seating plane (5), is between 7% and 15% of the diameter ΦA. Container (1) according to claim 11 characterized in that the guard Gv of the vault (7) is equal to 10% of the diameter ΦA. Container (1) according to any one of claims 1 to 12 characterized in that the guard Gp of the central pin (9), i.e. the height separating the upper end of the central pin (9) and the seating plane (5), is between 15% and 25% of the diameter ΦA. Container (1) according to claim 13 characterized in that the guard Gp of the central pin (9) is equal to 22% of the diameter ΦA. Container (1) according to any one of claims 1 to 14 characterized in that the diameter ΦP of the bottom of the central pin (9) is between 12% and 22% of the diameter ΦA. Container (1) according to claim 15 characterized in that the diameter ΦP of the bottom of the central pin (9) is equal to 18% of the diameter ΦA. Container (1) according to any one of claims 1 to 16 characterized in that the central pin (9) is composed of at least three consecutive rays from its bottom to the vault (7). Container (1) according to any one of claims 1 to 17 characterized in that the height H of the connecting wall (6), said connecting wall (6) extending from the base (5) to the lower end of the body (2) of the container (1), is between 25% and 40% of the diameter ΦA. Container (1) according to claim 18 characterized in that the height H of the connecting wall (6) is equal to 32% of the diameter ΦA. Container (1) according to any one of claims 18 or 19 characterized in that each main groove (11) extends up to a height h1 of the connecting wall (6), said height h1 being between 70% and 95% of the height H. Container (1) according to claim 20 characterized in that each main groove (11) extends up to a height h1 of the connecting wall (6), said height h1 being equal to 80% of the height H. Container (1) according to any one of claims 1 to 21 characterized in that the depth e11 of each main groove (11), at the level of the connecting wall (6), is between 20% and 60% of the value of the guard Gv of the vault (7). Container (1) according to claim 22 characterized in that the depth e11 of each main groove (11), at the level of the connecting wall (6), is equal to 40% of the value of the guard Gv of the vault (7). Container (1) according to any one of claims 1 to 23 characterized in that the maximum depth e12 of each main groove (11), at the level of the second section (7b) of the vault (7), is between 30% and 70% of the value of the guard Gv of the vault (7). Container (1) according to claim 24 characterized in that the maximum depth e12 of each main groove (11), at the level of the second section (7b) of the vault (7), is equal to 50% of the value of the guard Gv of the vault (7). Container (1) according to any one of claims 1 to 25 characterized in that the depth e13 of each main groove (11), at the level of the first section (7a) of the vault (7), is between 30% and 70% of the value of the guard Gv of the vault (7). Container (1) according to claim 26 characterized in that the depth e13 of each main groove (11), at the level of the first section (7a) of the vault (7), is equal to 50% of the value of the guard Gv of the vault (7). Container (1) according to any one of claims 1 to 27 characterized in that the width l11 of each main groove (11), at the level of the depth e11 of each main groove (11), i.e. at the level of the connecting wall (6), is between 90% and 170% of the value of said depth e11. Container (1) according to claim 28 characterized in that the width l11 of each main groove (11), at the level of the depth e11 of each main groove (11), i.e. at the level of the connecting wall (6), is equal to 135% of the value of said depth e11. Container (1) according to any one of claims 1 to 29 characterized in that the width l13 of each main groove (11), at the level of the depth e13 of each main groove (11), i.e. at the level of the first section (7a) of the vault (7), is between 80% and 160% of the value of said depth e13. Container (1) according to claim 30 characterized in that the width l13 of each main groove (11), at the level of the depth e13 of each main groove (11), i.e. at the level of the first section (7a) of the vault (7), is equal to 123% of the value of said depth e13. Container (1) according to any one of claims 1 to 31 characterized in that each intermediate reinforcing groove (12) extends up to a height h2 of the connecting wall (6), said height h2 being between 70% and 95% of the height H of the connecting wall (6). Container (1) according to claim 32 characterized in that each intermediate reinforcing groove (12) extends up to a height h2 of the connecting wall (6), said height h2 being equal to 80% of the height H of the connecting wall (6). Container (1) according to any one of claims 1 to 33 characterized in that the proximal end of each intercalary groove (12) is positioned close to the diameter ΦC. Container (1) according to any one of claims 1 to 34 characterized in that the maximum depth e2 of each intermediate reinforcing groove (12) is between 15% and 40% of the value of the guard Gv of the vault (7). Container (1) according to claim 35 characterized in that the maximum depth e2 of each intermediate reinforcing groove (12) is equal to 25% of the value of the guard Gv of the vault (7). Container (1) according to any one of claims 1 to 36 characterized in that the width l2 of each intermediate reinforcing groove (12), at the level of the maximum depth e2 of each intermediate reinforcing groove (12), is between 60% and 100% of the value of said maximum depth e2. Container (1) according to claim 37 characterized in that the width l2 of each intermediate reinforcing groove (12), at the level of the maximum depth e2 of each intermediate reinforcing groove (12), is equal to 76% of the value of said maximum depth e2. Container (1) according to any one of claims 1 to 38 characterized in that it comprises a total number of main grooves (11) and intermediate grooves (12) of reinforcement between 6 and 16. Mold base (23) for manufacturing a container (1) from a plastic preform, said mold base (23) being able to be mounted at one end of a mold (20) comprising two walls movable relative to each other and intended to form the body (2) of the container (1), said mold base (23) comprising at least a first annular part intended to form at least in part the heel, i.e. the seating surface (5), a second dome-shaped part intended to come into contact with an amorphous central area of ​​the preform to form the arch, characterized in that said second part being arranged so as to produce a container (1) comprising a base (3) according to any one of claims 1 to 39.

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