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

Abstract

Title: Container having a reinforced base and mold base for manufacturing such a container The present invention relates to a plastic container (1) having a body (2) and a base (3) extending from a lower end of the body (2), and the base (3) comprising at least one peripheral heel (4) defining a seat (5), and an arch (7) extending from a central area (8) to a heel (4), said heel (4) rising on a connecting wall (6) with the wall of the body (2) of the container (1), said base (3) having at least one central pin (9), said arch (7) extending from said central pin (9) to said heel (4),and the vault (7) comprising at least three so-called main grooves (11) and so-called intermediate grooves (12) for reinforcement which extend locally astride the base (5) between two main grooves (11); said container (1) is remarkable in that the body (2) has a substantially round cross-section and in that, between the main grooves (11), said vault (7) comprises in a vertical plane passing through the longitudinal axis of symmetry of the container, at least three sections (7a, 7b, 7c), a first section (7a) extending from the central pin (9) to a distance D from said vertical longitudinal axis of symmetry, said vault (7) having in this first section (7a) a concave profile along a first radius of curvature, the concavity being oriented towards the seating plane (5), a second section (7b) extending from said distance D to a distance C greater than distance D,said vault (7) having in this second section (7b) a concave profile along a second radius of curvature, thus forming between the first section (7a) and the second section (7b) a convex plateau, and a third section (7c) extending from said distance C to a distance E greater than distance C, said vault (7) having in this third section (7c) a substantially rectilinear profile. Figure for the abbreviation: Figure 1,

Description

Title of the invention: Container having a reinforced base and mold base for manufacturing such a container technical field

[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 conventionally 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 applications (typically sodas), the bases are generally petal-shaped, comprising alternating hemispherical valleys and projecting 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 side of the valley.

[0005] The petaloid bottom 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 feet and valleys. These constraints appear justified, however, by the relatively high price at which the products in question are sold.

[0007] However, petaloid bases are not suitable 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 have the disadvantage of being 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 is not able to withstand, without significant deformation, a low pressure, on the order of 1 bar, in the bottle. It has therefore been proposed to equip the base with radial ribs, designed to reinforce it and thus enable 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 surface of 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 in 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 carried out 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 of a container typically involves introducing a blank, such as a preform previously heated to a temperature above the glass transition temperature of the material, into a mold shaped to the container, and injecting a fluid (in particular a gas such as air) under pressure 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 stiffen their containers, as bi-orientation proves insufficient. As a result, two containers of equal weight do not necessarily have the same mechanical performance (strength, rigidity).

[0013] Furthermore, it is also known to stiffen the base by means of radial grooves. This is the case in particular for 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 is provided with 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 flattening and other stresses.

[0015] The base of this container maintains its mechanical stability without tipping over as long as the volume and / or pressure conditions within the container are normal. However, when these conditions are extreme, the base tends to collapse, even tipping over. Thus, when the container is stored in high heat, typically when palletized outdoors in direct sunlight, the temperature of the contents can reach or exceed 50°C, and the pressure increase induced by the expansion of the contents can exceed the threshold beyond 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 central chimney. These indentations have a generally approximately trapezoidal shape with the 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] FR2926034 is also known, which discloses a mold base for a mold for manufacturing, by blow molding or stretch blow molding, containers, particularly bottles, from preforms made of thermoplastic material, such as PET. These containers have a body and a base comprising a peripheral, ring-shaped seat internally connected to a central, vault-like zone consisting of a plurality of radiating cavities alternating with a series of radiating protrusions, which are distributed angularly and equidistantly around a central axis of said base. The mold base It comprises, for the molding of said central zone of said container bottom, several radiating projecting branches distributed angularly and equidistantly, extending approximately radially from the axis of the mold bottom, a central trunk having a lateral wall to which said branches are connected, and intervals forming segments of angular sectors regularly separating said branches from one another. Furthermore, each radiating projecting branch has an upper part in the form of an inclined platform descending from the center towards the periphery with at least two points of inflection in the curve.

[0018] In theory, it would be possible to form deep recesses (in particular a deep vault) in the bottom, which would increase its mechanical strength. However, this shaping technique, however effective, requires both an additional amount of material, incompatible with the aforementioned weight reduction requirements, and a high blowing pressure, incompatible with energy-saving requirements, which, on the contrary, require a reduction in the blowing pressure necessary for forming the container.

[0019] There is therefore a need for a container whose mechanical performance is improved with equivalent blowability (i.e. the ability of the container to be formed by blowing), whose optimized bottom shape gives it a good compromise between blowability and rigidity, including for containers obtained in recycled PET called rPET which has different mechanical properties from those of 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 drawbacks by proposing a container of simple and inexpensive design, obtained from recycled PET called 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 base, 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 around the longitudinal X axis of the vessel and whose concavity is oriented towards the base, said vault extending from said central pin to said heel, and the vault comprising at least three so-called principal grooves extending radially from the central pin to the connecting wall, the concavity of said principal grooves being oriented towards the plane of the base and said principal grooves being angularly distributed around said central pin, and so-called intermediate reinforcing grooves which extend locally astride the base between two principal grooves, said vessel comprising a vertical longitudinal axis of symmetry; said vessel is remarkable in that the body has a substantially round cross-section and in that, between the principal grooves, said vault comprises in a vertical plane passing through the longitudinal axis of symmetry of the vessel, at least three sections,a first section extending from the central post to a distance D from said vertical longitudinal axis of symmetry, said vault having in this first section a concave profile along a first radius of curvature, the concavity being oriented towards the foundation plane, a second section extending from said distance D to a distance C greater than D, said vault having in this second section a concave profile along a second radius of curvature, thus forming a convex plateau between the first and second sections, and a third section extending from said distance <1> C up to a distance E greater than distance C, said vault having in this third section a substantially rectilinear profile.

[0022] Preferably, said vault comprises a fourth section extending from said distance E to a distance A corresponding to the base diameter of the bottom, and more particularly to the distance separating the two smallest opposite sides of the base.

[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 average slope of the third section of the vault is 5° with respect to the plane of the base.

[0025] Furthermore, the distance A is between 60% and 90% of the distance B of the container body, said distance B of the body corresponding to the distance separating the two smallest opposite sides of the container body and, preferably, the distance <1> A is equal to 75% of the distance B from the body of the container.

[0026] Furthermore, the distance <e>Ad, corresponding to the diameter of the circle in which the bottom of the container is inscribed, is between 60% and 90% of the distance <e>Bd corresponds to the diameter of the circle in which the body of the container is inscribed and, preferably, the distance <e>Ad is equal to 73% of the distance <e>Bd.

[0027] Said distance D, 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 comprised between 55% and 70% of distance A and, preferably, said distance D is equal to 62% of distance A.

[0028] Furthermore, the distance C 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 90% of the distance A of the seat and, preferably, the distance C is equal to 80% of the distance A.

[0029] In addition, the Gv guard of the vault, that is to say the height separating the lower end of the central pin and the seating plane, is between 7% and 20% of the distance A from the seating and, preferably, the Gv guard of the vault is equal to 11% of the distance A.

[0030] Furthermore, the guard 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 30% of the distance A from the seating and, preferably, the guard Gp of the central pin is equal to 20% of the distance A.

[0031] Furthermore, the distance <e>P from the bottom of the central pawl is between 15% and 25% of the distance A from the seat and, preferably, the distance P from the bottom of the central pawl is equal to 20% of the distance A from the seat.

[0032] Preferably, said central pawl is composed of at least three consecutive rays from its base to the vault.

[0033] 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 distance A and, preferably, the height H of the connecting wall is equal to 32% of the distance A.

[0034] Preferably, each main groove extends to a height hl of the connecting wall, said height hl being between 70% and 95% of the height H and, preferably, each main groove extends to a height hl of the connecting wall, said height hl being equal to 81% of the height H.

[0035] Furthermore, the depth el 1 of each main groove, at the level of the connecting wall, is between 15% and 45% of the value of the Gv guard of the vault and, preferably, the depth el 1 of each main groove, at the level of the connecting wall, is equal to 28.5% of the value of the Gv guard of the vault.

[0036] According to another feature, the depth el2 of each main groove, at the level of the second section of the vault, is between 15% and 50% of the value of the Gv guard of the vault and, preferably, the depth el2 of each main groove, at the level of the second section of the vault, is equal to 30% of the value of the Gv guard of the vault.

[0037] Furthermore, the depth el3 of each main groove, at the level of the first section of the vault, is between 20% and 60% of the value of the guard Gv of the vault and, preferably, the depth el3 of each main groove, at the level of the first section of the vault, is equal to 42% of the value of the vault's Gv guard.

[0038] Furthermore, the width 111 of each main groove, at the level of the depth el 1 of each main groove, i.e. at the level of the connecting wall, is between 55% and 110% of the value of said depth el 1 and, preferably, the width 111 of each main groove, at the level of the depth el 1 of each main groove, i.e. at the level of the connecting wall, is equal to 78% of the value of said depth el 1.

[0039] Furthermore, the width 113 of each main groove, at the level of the depth el3 of each main groove, i.e. at the level of the first section of the vault, is between 90% and 170% of the value of said depth el3 and, preferably, the width 113 of each main groove, at the level of the depth el3 of each main groove, i.e. at the level of the first section of the vault, is equal to 137% of the value of said depth el3.

[0040] According to another feature, each intermediate reinforcing groove extends up 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 intermediate reinforcing groove extends up to a height h2 of the connecting wall, said height h2 being equal to 81% of the height H of the connecting wall.

[0041] Furthermore, the proximal end of each intercalary groove is positioned close to the distance C.

[0042] In addition, the depth e2 of each intermediate reinforcing groove is between 20% and 40% of the value of the Gv guard of the vault and, preferably, the depth e2 of each intermediate reinforcing groove is equal to 28.5% of the value of the Gv guard of the vault.

[0043] Furthermore, the width 12 of each reinforcing intermediate groove, at the level of the depth e2 of each reinforcing intermediate groove, is between 65% and 100% of the value of said depth e2 and, preferably, the width 12 of each reinforcing intermediate groove, at the level of the depth e2 of each reinforcing intermediate groove, is equal to 76% of the value of said depth e2.

[0044] Incidentally, the bottom of the container according to the invention comprises a total number of main grooves and intermediate reinforcing grooves of between 6 and 16.

[0045] Another object of the invention relates to a mold base for manufacturing a container from a plastic preform, said mold base being suitable for mounting 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 portion intended to form at least in part the base, i.e. the seating surface, a second dome-shaped portion intended to come into contact with an amorphous central zone of the preform to form the vault; said mold base is remarkable in that said second part is arranged to produce a container comprising a base according to the invention. Brief description of the drawings

[0046] 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 accompanying drawings in which:

[0047] [Fig-1] is a perspective view from below of a plastic container following the invention,

[0048] [Fig.2] is a perspective view of the bottom of the container according to the invention,

[0049] [Fig.3] is a bottom view of the base of the container according to the invention,

[0050] [Fig.4] is a perspective view of the inside of the bottom of the container conforming to the invention,

[0051] [Fig.5] is a diametrical cross-sectional view of the bottom of the container according to the invention,

[0052] [Fig.6] is an exploded perspective view of a mold, including a mold bottom, for the manufacture of a container according to the invention. Method of embodying the invention

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Said container 1 usually comprises a body 2 forming a wall and extending from a bottom 3, surmounted by a shoulder, leading to a neck, ending in 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.

[0057] With reference to Figures 1 to 5, the base 3 comprises a peripheral heel 4 which terminates in a bearing surface 5, also called a seat, perpendicular to the longitudinal axis of the container 1, said bearing surface 5 defining the lower end of the container 1 and allowing the container 1 to be placed vertically on a flat surface. In addition, said heel 4 extends up onto a wall called the connecting wall 6 with the wall of the body 2 of the container 1.

[0058] Furthermore, the base 3 also comprises 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 stress, 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 extending up onto the connecting wall 6 with the wall of the body 2 of the container 1. Said central zone 8 has a central pin 9 projecting inwards from 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 an amorphous pellet 10 at its center 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 molding of the container 1.

[0059] Furthermore, said vault 7 comprises 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 bearing surface 5 and said main grooves 11 being angularly distributed around said central pin 9, and intermediate reinforcing grooves 12 which locally extend across the bearing surface 5 between two main grooves 11

[0060] In this particular embodiment, said vault 7 comprises six main grooves 11 and six 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.

[0061] Furthermore, in this embodiment, said container 1 has a vertical longitudinal axis of symmetry and the body 2 has a cross-section of a so-called square shape. More precisely, in the particular embodiment, the body 2 has a cross-section of a substantially square shape such that each side of the body 2 has a distance B; however, said body 2 may have a cross-section of a substantially rectangular shape such that the distance B of the body 2 shall be denoted as the distance separating the two shorter opposite sides of the body 2 from the container and the distance B' of the body 2 as the distance separating the two longer opposite sides of the body 2 from the container 1, B' being equal to B in the case of a square cross-section of the body 2.

[0062] With reference to [Fig. 5], between the main grooves 11, said vault 7 comprises, in a vertical plane passing through the longitudinal axis of symmetry of the container, at least three sections, a first section 7a extending from the central pin 9 to a distance D from said vertical longitudinal axis of symmetry, said vault 7 presenting in this first section 7a a concave profile along a first radius of curvature, the concavity being oriented towards the ground plane 5, a second section 7b extending from said distance D to a distance C greater than D, said vault 7 presenting in this second section 7b a concave profile along a second radius of curvature, thus forming between the first section 7a and the second section 7b a convex plateau, and a third section 7c extending from said distance C to a distance E greater than distance C, said vault 7 presenting in this third section 7c a substantially rectilinear profile.

[0063] Preferably, said vault 7 comprises a fourth section 7d extending from said distance E to a distance A corresponding to the diameter of the base of the bottom 3, and more particularly to the distance separating the two smallest opposite sides of the base 5. It will be noted that said distance A corresponds to the diameter of the inscribed circle in which the square-sectioned base 3 extends and, in the end, to the diagonal of the square-sectioned base 3.

[0064] Furthermore, 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.

[0065] Preferably, the average slope of the third section 7c of the vault 7 is 5° with respect to the plane of the base 5.

[0066] In addition, the distance A is between 60% and 90% of the distance B of the body 2 of the container, said distance B of the body 2 corresponding to the distance separating the two smallest opposite sides of the body 2 of the container 1 as previously seen and, preferably, the distance A is equal to 75% of the distance B of the body 2 of the container 1.

[0067] Furthermore, the distance <e>Ad, corresponding to the diameter of the circle in which the bottom 3 of the container 1 is inscribed, is between 60% and 90% of the distance <e>Bd corresponding to the diameter of the circle in which the body 2 of the container 1 is inscribed and, preferably, the distance <e>Ad is equal to 73% of the distance <e>Bd.

[0068] Said distance D 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 55% and 70% of the distance A and, preferably, said distance D is equal to 62% of the distance A.

[0069] Furthermore, the distance C 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 90% of the distance A of the base 5 and, preferably, the distance C is equal to 80% of the distance A.

[0070] In addition, 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 20% of the distance A of the seating 5 and, preferably, the guard Gv of the vault 7 is equal to 11% of the distance A.

[0071] Furthermore, the guard Gp of the central pin 9, that is to say the height separating the upper end of the central pin 9 and the seat plane 5, is between 15% and 30% of the distance A of the seat 5 and, preferably, the guard Gp of the central pin is equal to 20% of the distance A.

[0072] Furthermore, the distance <pp du fond pion central 9 est comprise entre 15% et 25% de la distance a l’assise 5 et, préférence, <pp égale à 20% 5.

[0073] 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 frustoconical or substantially hemispherical shape without going out of the scope of the invention.

[0074] 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 distance A and, preferably, the height H of the connecting wall 6 is equal to 32% of the distance A.

[0075] Preferably, each main groove 11 extends to a height hl of the connecting wall 6, said height hl being between 70% and 95% of the height H and, preferably, each main groove 11 extends to a height hl of the connecting wall 6, said height hl being equal to 81% of the height H.

[0076] Furthermore, the depth el 1 of each main groove 11, at the level of the connecting wall 6, is between 15% and 45% of the value of the guard Gv of the vault 7 and, preferably, the depth el 1 of each main groove 11, at the level of the connecting wall 6, is equal to 28.5% of the value of the guard Gv of the vault 7.

[0077] According to another feature, the depth el2 of each main groove 11, at the level of the second section 7b of the vault 7, is between 15% and 50% of the value of the guard Gv of the vault 7 and, preferably, the depth el2 of each main groove 11, at the level of the second section 7b of the vault 7, is equal to 30% of the value of the guard Gv of the vault 7.

[0078] Furthermore, the depth el3 of each main groove 11, at the level of the first section 7a of the vault 7, is between 20% and 60% of the value of the guard Gv of the vault 7 and, preferably, the depth el3 of each main groove 11, at the level of the first section 7a of the vault 7, is equal to 42% of the value of the guard Gv of the vault 7.

[0079] Furthermore, the width 111 of each main groove 11, at the level of the depth el 1 of each main groove 11, i.e. at the level of the connecting wall 6, is between 55% and 110% of the value of said depth el 1 and, preferably, the width 111 of each main groove 11, at the level of the depth el 1 of each main groove 11, i.e. at the level of the connecting wall 6, is equal to 78% of the value of said depth el 1.

[0080] Furthermore, the width 113 of each main groove 11, at the level of the depth el3 of each main groove 11, i.e. at the level of the first section 7a of the vault 7, is between 90% and 170% of the value of said depth el3 and, preferably, the width 113 of each main groove, 11 at the level of the depth el3 of each main groove 11, i.e. at the level of the first section 7a of the vault 7, is equal to 137% of the value of said depth el3.

[0081] According to another feature, each reinforcing intermediate 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 reinforcing intermediate groove 12 extends up to a height h2 of the connecting wall 6, said height h2 being equal to 81% of the height H of the connecting wall 6.

[0082] Furthermore, the proximal end of each reinforcing intercalary groove 12 is positioned close to the distance C.

[0083] In addition, the depth e2 of each intermediate reinforcing groove 12 is between 20% and 40% of the value of the Gv guard of the vault 7 and, preferably, the depth e2 of each intermediate reinforcing groove 12 is equal to 28.5% of the value of the Gv guard of the vault 7.

[0084] Furthermore, the width 12 of each reinforcing intermediate groove 12, at the level of the depth e2 of each reinforcing intermediate groove 12, is between 65% and 100% of the value of said depth e2 and, preferably, the width 12 of each reinforcing intermediate groove 12, at the level of the depth e2 of each reinforcing intermediate groove 12, is equal to 76% of the value of said depth e2.

[0085] It will be noted that, in the case where said body 2 has a substantially rectangular cross-section, not shown in the figures, the distance B of body 2 will be denoted as the distance separating the two shorter opposite sides of body 2 from the container, and the distance B' of body 2 will be denoted as the distance separating the two longer opposite sides of body 2 from the container 1, B' being equal to B in the case of a square cross-section of body 2. Similarly, the distances A, C, D, and E in the longer sides will be denoted A', C', D', and E' respectively. In this respect, the relationships between the different distances A, B, C, D, E, etc., apply identically to the different distances A', B', C', D', E', etc.

[0086] With reference to [Fig.6], a molding unit 19 according to the invention is described for forming, from a blank, usually typically a preform, a container 1 according to the invention, such as a bottle or a can, according to the invention.

[0087] Said molding unit 19, with reference to [Fig. 6], comprises a mold 20 having a lateral wall 21 that defines a cavity 22 in the shape of a portion of the container. Said mold 20 further comprises a base 23 in the shape of the base of the container, said 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 within the mold 20 comprising two walls movable relative to each other and intended to form the body of the container.

[0088] Thus, said mold base 23 comprises at least a first substantially round 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 vault, said second part being arranged so as to produce a container comprising a base according to the invention as described above.

[0089] Finally, it is quite clear that the examples just given are only particular illustrations and in no way limiting as to the fields of application of the invention.< / pp> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e>

Claims

1. Demands 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 area (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 (4), 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 round cross-section and in that, between the main grooves (11), said vault (7) comprises in a vertical plane passing through the longitudinal axis of symmetry of the vessel (1), at least three sections (7a, 7b, 7c), a first section (7a) extending from the central pin (9) to a distance D from said vertical longitudinal axis of symmetry, said vault (7) having in this first section (7a) a concave profile with a first radius of curvature, with the concavity oriented towards the seating plane (5),a second section (7b) extending from said distance D to a distance C greater than distance D, said vault (7) having in this second section (7b) a concave profile along a second radius of curvature, thus forming between the first section (7a) and the second section (7b) a convex plateau, and a third section (7c) extending from said distance C to a distance E greater than distance C, said vault (7) having in this third section (7c) a substantially rectilinear profile.

2. Container (1) according to claim 1 characterized in that said vault (7) comprises a fourth section (7d) extending from said distance E to a distance A corresponding to the seat diameter (5) of the bottom (3), and more particularly to the distance separating the two smallest opposite sides of the seat (5).

3. 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).

4. Container (1) according to claim 3 characterized in that the average slope of the third section (7c) of the vault (7) is 5° with respect to the plane of the seat (5).

5. Container (1) according to any one of claims 2 to 4 characterized in that the distance A is between 60% and 90% of the distance B of the body (2) of the container (1), said distance B of the body (2) corresponding to the distance separating the two smallest opposite sides of the body (2) of the container (1).

6. Container (1) according to claim 5 characterized in that the distance A is equal to 75% of the distance B of the body (2) of the container (1).

7. Container (1) according to any one of claims 2 to 6 characterized in that the distance OAd corresponding to the diameter of the circle in which the bottom (3) of the container (1) is inscribed is between 60% and 90% of the distance OBd corresponding to the diameter of the circle in which the body (2) of the container (1) is inscribed.

8. Container (1) according to claim 7 characterized in that the distance OAd is equal to 73% of the distance OBd.

9. Container (1) according to any one of claims 5 or 6 characterized in that the distance D 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 55% and 70% of the distance A.

10. Container (1) according to claim 9 characterized in that said distance D is equal to 62% of distance A.

11. Container (1) according to any one of claims 5 to 10 characterized in that the distance C corresponding to the distal end of the second section (7b) of the vault (7), and corresponding to the end

12.

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22. proximal of the third section (7c) of the vault (7), is between 70% and 90% of the distance A of the base (5). Container (1) according to claim 11 characterized in that the distance C is equal to 80% of the distance A. Container (1) according to any one of claims 1 to 12 characterized in that the guard Gv of the vault (7), i.e. the height separating the lower end of the central pin (9) and the seating plane (5), is between 7% and 20% of the distance A of the seating (5). Container (1) according to claim 13 characterized in that the guard Gv of the vault (7) is equal to 11% of the distance A. Container (1) according to any one of claims 1 to 14 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 30% of the distance A of the seat (5). Container (1) according to claim 15 characterized in that the guard Gp of the central pin (9) is equal to 20% of the distance A. Container (1) according to any one of claims 1 to 16 characterized in that the distance <1> P of the bottom of the central pawl (9) is between 15% and 25% of the distance A of the seat (5). Container (1) according to claim 17 characterized in that the distance <e>P of the bottom of the central pawl (9) is equal to 20% of the distance A of the seat (5). Container (1) according to any one of claims 1 to 18 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 19 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 distance A. Container (1) according to claim 20 characterized in that the height H of the connecting wall (6) is equal to 32% of the distance A. Container (1) according to any one of claims 20 or 21 characterized in that each main groove (11) extends up to a height hl of the connecting wall (6), said height hl being between 70% and 95% of the height H.

23. Container (1) according to claim 22 characterized in that each main groove (11) extends up to a height hl of the connecting wall (6), said height hl being equal to 81% of the height H.

24. Container (1) according to any one of claims 1 to 23 characterized in that the depth el 1 of each main groove (11), at the level of the connecting wall (6), is between 15% and 45% of the value of the guard Gv of the vault (7).

25. Container (1) according to claim 24 characterized in that the depth el 1 of each main groove (11), at the level of the connecting wall (6), is equal to 28.5% of the value of the guard Gv of the vault (7).

26. Container (1) according to any one of claims 1 to 25 characterized in that the depth el2 of each main groove (11), at the level of the second section (7b) of the vault (7), is between 15% and 50% of the value of the guard Gv of the vault (7).

27. ​​Container (1) according to claim 26 characterized in that the depth el2 of each main groove (11), at the level of the second section (7b) of the vault (7), is equal to 30% of the value of the guard Gv of the vault (7).

28. Container (1) according to any one of claims 1 to 27 characterized in that the depth el3 of each main groove (11), at the level of the first section (7a) of the vault (7), is between 20% and 60% of the value of the guard Gv of the vault (7).

29. Container (1) according to claim 28 characterized in that the depth el3 of each main groove (11), at the level of the first section (7a) of the vault (7), is equal to 42% of the value of the guard Gv of the vault (7).

30. Container (1) according to any one of claims 1 to 29 characterized in that the width 111 of each main groove (11), at the level of the depth el 1 of each main groove (11), i.e. at the level of the connecting wall (6), is between 55% and 110% of the value of said depth el 1.

31. Container (1) according to claim 30 characterized in that the width 111 of each main groove (11), at the level of the depth ell 1 of each main groove (11), i.e. at the level of the connecting wall (6), is equal to 78% of the value of said depth ell.

32. Container (1) according to any one of claims 1 to 31 characterized in that the width 113 of each main groove (11), at the level of the depth el3 of each main groove (11), i.e. at the level of the first section (7a) of the vault (7), is between 90% and 170% of the value of said depth el3.

33. Container (1) according to claim 32 characterized in that the width 113 of each main groove (11), at the level of the depth el3 of each main groove (11), i.e. at the level of the first section (7a) of the vault (7), is equal to 137% of the value of said depth el3.

34. Container (1) according to any one of claims 1 to 33 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).

35. Container (1) according to claim 34 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 81% of the height H of the connecting wall (6).

36. Container (1) according to any one of claims 1 to 35 characterized in that the proximal end of each intercalated groove (12) is positioned close to the distance C.

37. Container (1) according to any one of claims 1 to 36 characterized in that the depth e2 of each intermediate reinforcing groove (12) is between 20% and 40% of the value of the guard Gv of the vault (7).

38. Container (1) according to claim 37 characterized in that the depth e2 of each intermediate reinforcing groove (12) is equal to 28.5% of the value of the guard Gv of the vault (7).

39. Container (1) according to any one of claims 1 to 38 characterized in that the width 12 of each reinforcing intermediate groove (12), at the depth e2 of each groove interlayer (12) of reinforcement, is between 65% and 100% of the value of said depth e2.

40. Container (1) according to claim 39 characterized in that the width 12 of each intermediate reinforcing groove (12), at the level of the depth e2 of each intermediate reinforcing groove (12), is equal to 76% of the value of said depth e2.

41. Container (1) according to any one of claims 1 to 40 characterized in that it comprises a total number of main grooves (11) and intermediate reinforcing grooves (12) of between 6 and 16.

42. 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 is arranged so as to produce a container (1) comprising a base (3) according to any one of claims 1 to 41.< / e>

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