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

Abstract

Title: Container having a reinforced base and mold base for the manufacture of such a container The present invention relates to a container (1) having a body (5) and a base (6), said body (5) comprising a shoulder (4) and a neck (2), and the base (6) comprising at least a peripheral heel (7) defining a seat (8), and an arch (10); The said vessel is remarkable in that the said base (6) comprises at least one central pin (12) having a generally frustoconical lateral wall of revolution about the longitudinal axis X of the vessel (1) and whose concavity is oriented towards the base (8), the said vault (10) extending from the said central pin (12) to the said foot (7) and having a height between 11% and 18% of the base diameter ΦA, and the said central pin (12) having a diameter between 15% and 25% of the base diameter ΦA and overhanging the vault (10) by a height between 9% and 18% of the said base diameter ΦA. 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 (on the order of 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, is carried out by pouring a drop of liquefied inert gas onto the surface of the liquid, immediately before sealing the container. This operation, called 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 can also be 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] A well-known method for increasing the rigidity of a container is "thermal fixing", which consists of heating the wall of the mold to thermally increase the degree of crystallinity as described in document FR2649035 in particular and which is commonly used for HR (initials of the English term "heat resistant") applications, in which the container is filled while hot.

[0014] Document FR2649035 describes a process in which a container is molded by stretch-blowing from a polyethylene terephthalate (PET) preform. The body of the preform alone is heated to a temperature at which longitudinal and transverse stretching do not induce stress in the material constituting the container. The preform is then transferred into a mold, the walls of which are heated and maintained at a temperature lower than that of the body of the preform, where it is stretched longitudinally and blown. Thus, the two-way stretching ratio involved in going from the preform to the container is between 7 and 9.

[0015] However, due to its cost and the reduced production rate it imposes, this type of process cannot be generalized to ordinary applications such as still water. Furthermore, this type of process would not improve the mechanical resistance of the still water containers (bottles). For these applications, the structural rigidity of the base depends primarily on its shape.

[0016] In this regard, it is known to stiffen the base by means of radial grooves. This is the case in particular for documents FR2753435, FR2883550 and FR2926034.

[0017] 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 maximum resistance to flattening and other stresses.

[0018] 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.

[0019] 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 sides 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.

[0020] 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 container 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 container base.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 part 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.

[0021] 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.

[0022] There is therefore a need for a container whose mechanical performance is improved while maintaining equivalent blowability (i.e., the container's ability to be formed by blowing), and whose optimized base shape provides a good compromise between blowability and rigidity, including for containers made from recycled PET said rPET which has different mechanical properties than PET, whose base 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

[0023] 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.

[0024] Another object of the invention is to provide a base without ribs going up on the heel, for aesthetic reasons in accordance with current market trends concerning sensitive products, while offering a structure which allows high speeds without unwinding of the base at the machine exit and which has increased resistance to the mechanical stresses caused by the rPET (drop test).

[0025] 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 a peripheral heel defining a seat, and an arch extending from a central area to said heel, said heel rising up on a connecting wall with the wall of the container body;said container is remarkable in that said base comprises at least one central pin having a generally frustoconical lateral wall of revolution around the longitudinal X axis of the container and whose concavity is oriented towards the base, said vault extending from said central pin to said heel and having a height between 11% and 18% of the base diameter, and said central pin having a diameter between 15% and 25% of the base diameter and overhanging the vault by a height between 9% and 18% of said base diameter.

[0026] Advantageously, the vault has a substantially spherical shape of radius R centered on the longitudinal axis of the container, said radius R of the vault being between 70% and 120% of the seat diameter.

[0027] Preferably, said radius R of the vault is equal to 86% of the base diameter.

[0028] Furthermore, the base of the central pin consists of a spherical cap whose concavity is oriented towards the seat and whose radius of curvature is between 25% and 75% of the seat diameter.

[0029] Preferably, the radius of curvature of the bottom of the central pin is equal to 50% of the seat diameter.

[0030] Advantageously, the central pawl is composed of at least three consecutive rays from its base to the vault.

[0031] Furthermore, the width of the seat is between 0.5% and 5% of the seat diameter and, preferably, is equal to 2.4% of the seat diameter.

[0032] Preferably, the vault comprises between two and six so-called main grooves extending radially from the central pin in the direction of the base, the concavity of said main grooves being oriented towards the base plane and said main grooves being angularly distributed around said central pin.

[0033] Furthermore, the distal end of each main groove extends to a distance from the seat of between 8% and 20% of the value of said seat diameter

[0034] Advantageously, the distal end of each main groove extends to a distance from the seat of approximately 14% of the value of said seat diameter.

[0035] Furthermore, the bottom of each main groove has a curved radial profile such that the depth of each main groove decreases from the central pin to its distal end.

[0036] In addition, the maximum depth of each main groove is between 6% and 18% of the seat diameter and preferably is about 8% of the seat diameter.

[0037] Said radial radius of curvature of the bottom of each main groove is between 30% and 60% of the seat diameter and, preferably, is equal to 38.5% of the seat diameter.

[0038] Moreover, the bottom of each main groove has, in cross-section of said main groove, a curvilinear shape whose radius of curvature is variable from the central pin to its distal end.

[0039] Said radius of curvature of the bottom of each main groove is increasing from the central pin to its distal end.

[0040] Preferably, said radius of curvature of the bottom of each main groove is substantially constant from the central pin to a distance of about 40% of the total length of the main groove, representing a first section of the main groove, and said radius of curvature of the bottom of each main groove is increasing from the end of said first section to the distal end of the main groove.

[0041] Moreover, the bottom of each main groove has a substantially constant width L1 from the central pin to a distance of about 40% of the total length of the main groove, i.e. in the first section of the main groove, and an increasing width L2 from the end of said first section to the distal end of the main groove.

[0042] Said width L1 in the first section of each main groove is between 1% and 6% of the seat diameter, and preferably equal to 3% of said seat diameter.

[0043] Furthermore, the width L2, between the end of the first section and the distal end of the main groove, is between 200% and 700% of the width L1 and, preferably, equal to 393% of said width L1.

[0044] In addition, the vault has between two and six so-called secondary grooves extending radially from the central pin in the direction of the base along a length less than that of the main grooves, the concavity of said secondary grooves being oriented towards the base plane and said secondary grooves being angularly distributed around said central pin extending between two main grooves.

[0045] The distal end of each secondary groove extends to a distance from the seat of between 12% and 25% of the value of said seat diameter.

[0046] Preferably, the distal end of each secondary groove extends to a distance from the seat of about 19% of the value of said seat diameter.

[0047] Advantageously, the bottom of each secondary groove has a curved radial profile such that the depth of each secondary groove decreases from the central pin to its distal end.

[0048] Furthermore, the maximum depth of each secondary groove is between 6% and 18% of the seat diameter and, preferably, is about 8% of the seat diameter.

[0049] Said radial radius of curvature of the bottom of each secondary groove is between 25% and 55% of the seat diameter and, preferably, is equal to 31.2% of the seat diameter.

[0050] Moreover, the bottom of each secondary groove has, in cross-section of said secondary groove, a curvilinear shape whose radius of curvature is constant or variable from the central pin to its distal end.

[0051] In addition, the bottom of each secondary groove has a decreasing width from the central pin to its distal end, the bottom having a width L3 at the central pin and a width L4 at the distal end of the secondary groove.

[0052] Said width L3 of the bottom of each secondary groove is between 1 and 7% of the seat diameter and, preferably, is equal to 3.5% of said seat diameter.

[0053] Preferably, said width L4 of the bottom of each secondary groove is between 30% and 130% of the width L3 and, preferably, is equal to 80% of the width L3.

[0054] Another object of the invention relates to a mold base for manufacturing a container from a plastic preform, said mold base being suitable for being 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 plane, a second dome-shaped part intended to come into contact with an amorphous central zone of the preform to form the arch of the bottom of the container, remarkable in that said second part is arranged so as to produce a container comprising a bottom according to the invention. Brief description of the drawings

[0055] 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:

[0056] [Fig-1] is a perspective view from below of a plastic container according to the invention,

[0057] [Fig.2] is a perspective view from below of the bottom of the plastic container according to the invention,

[0058] [Fig.3] is a bottom view of the base of the plastic container according to the invention,

[0059] [Fig.4] is a torn top perspective view of the bottom of the container in plastic according to the invention

[0060] [Fig. 5] is a torn side view of the bottom of the following plastic container the invention, with dimensions,

[0061] [Fig.6] is a top view of the bottom of the plastic container according to the invention, with quotes,

[0062] [Fig.7] is a second torn side view of the bottom of the following plastic container the invention, with dimensions,

[0063] [Fig.8] is a top perspective view of an embodiment variant of the bottom of the plastic container according to the invention,

[0064] [Fig.9] is a bottom view of the embodiment variant of the bottom of the container in plastic according to the invention shown in [Fig.8],

[0065] [Fig. 10] is a top perspective view of a second embodiment of the bottom of the plastic container according to the invention,

[0066] [Fig. 11] is a side view of the second embodiment of the bottom of the plastic container according to the invention shown in [Fig. 10],

[0067] [Fig. 12] is a radial cross-sectional view of the second embodiment of the bottom of the plastic container according to the invention shown in Figures 10 and 11,

[0068] [Fig. 13] 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

[0069] 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.

[0070] With reference to [Fig.1], the container 1 according to the invention consists, in this case, of a bottle made by stretch blow molding from a preform in thermoplastic material, for example in PET (polyethylene terephthalate) and / or rPET (recycled polyethylene terephthalate), or similar.

[0071] Said container 1 comprises, at an upper end, a neck 2, provided with a mouth 3. In the extension of the neck 2, towards the lower end of the container 1, the latter usually comprises, in its upper part, a shoulder 4 going outwards in the opposite direction to the neck 2, this shoulder 4 being extended by a lateral wall or body 5, generally substantially cylindrical in shape of revolution about a vertical longitudinal axis X, represented in dashed lines, of the container 1.

[0072] The container 1 further comprises a base 6 extending opposite the neck 2 from a lower end of the body 5. Said base 6 comprises a peripheral heel 7 in the form of an annular ridge extending substantially axially in line with the body 5. The heel 7 terminates in a support 8, also called a base, perpendicular to the longitudinal axis X of the container 1, said base 8 defining the lower end of the container 1 and enabling the container 1 to be placed vertically on a flat surface. In addition, said heel 7 extends up a wall called a connecting wall 9 with the wall of the body 5 of the container 1.

[0073] Note <1> A is the diameter of the base 8, the term "diameter" covering not only the case (illustrated) where the container 1 (and therefore the base 6) has a circular outline, but also the case where the container 1 would have a polygonal outline (for example square), in which case the term "diameter" would designate the diameter of the circle in which this polygon would be inscribed without going out of the scope of the invention.

[0074] Furthermore, the bottom 6 also includes a concave vault 10, in the form of a substantially spherical cap 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 10 extends from the heel 7 to a central area 11 of the bottom 6 forming a central pin 12 projecting towards the inside of the container 1, with in its center an amorphous pellet 12b which corresponds to the injection area 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.

[0075] Furthermore, with reference to figures 2 to 7, said base 6 comprises a central pin 12 having a lateral wall that is generally frustoconical or cylindrical of revolution around the longitudinal axis of the container and whose concavity is oriented towards the base 8, said vault 10 extending from the base of said central pin 12 to said heel 7, and the vault 10 comprises four main grooves 13 extending radially from the central pin 12 towards the base 8, the concavity of said main grooves 13 being oriented towards the base 8 and said main grooves 13 being angularly distributed around said central pin 12.

[0076] In this particular embodiment, said base 6 has only four main grooves 13; however, said base 6 may have between two and six main grooves 13 depending, in particular, on the dimensions of said container 1.

[0077] Furthermore, the distal end of each main groove 13 extends to a distance from the seat 8 of approximately 14% of the value of said seat diameter <1> A. The bottom of each main groove 13 has a curved radial profile such that the depth of each main groove 13 decreases from the central pin 12 to its distal end. The radial radius of curvature R5 of the bottom of each main groove 13 is between 30% and 60% of the seat diameter. <1> A and, preferably, is equal to 38.5% of the seat diameter <1> HAS.

[0078] The bottom of each main groove 13 has, in cross-section of said main groove, a curvilinear shape whose radius of curvature varies from the central pin 12 to its distal end. In the preferred embodiment, shown in the figures, said radius of curvature of the bottom of each main groove 13 is substantially constant from the central pin 12 to a distance of approximately 40% of the total length of said main groove 13, representing a first section of the main groove, and said radius of curvature of the bottom of each main groove 13 increases from the end of said first section to the distal end of the main groove 13.

[0079] Furthermore, at the same time, the bottom of each main groove 13 has a substantially constant width L1 from the central pin 12 to a distance of approximately 40% of the total length of said main groove 13, i.e., in the first section of the main groove 13, and an increasing width L2 from the end of said first section to the distal end of the main groove 13. Preferably, the width L1 in the first section of each main groove 13 is between 1% and 6% of the seat diameter. <1> A, and preferably, is equal to 3% of said seat diameter <1> A. Furthermore, the width L2, between the end of the first section and the distal end of the main groove 13, is between 200% and 700% of the width L1 and, preferably, is equal to 393% of said width LL

[0080] In addition, the distal end of each main groove extends to a distance from the seat of between 8% and 20% of the value of said seat diameter and, preferably, extends to a distance from the seat of about 14% of the value of said seat diameter.

[0081] Preferably, the maximum depth of each main groove is between 6% and 18% of the seat diameter and, preferably, is about equal to 8% of said seat diameter.

[0082] According to an alternative embodiment, not shown in the figures, said radius of curvature of the bottom of each main groove 13 may be increasing from the central pin 13 to its distal end.

[0083] Furthermore, the vault 10 has four so-called secondary grooves 14 extending radially from the central pin 12 towards the course 8 along a length less than that of the main grooves 13, the concavity of said secondary grooves 14 being oriented towards the course 8 and said secondary grooves 14 being angularly distributed around said central pin 12 extending between two main grooves 13.

[0084] In this particular embodiment, the base 6 thus comprises four main grooves 13 and four secondary grooves 14; however, the base 6 may comprise between two and six main grooves 13 and between two and six secondary grooves 14, said base 6 preferably comprising the same number of main grooves 13 and secondary grooves 14, without departing from the scope of the invention.

[0085] It will be observed that, in this particular embodiment, the secondary grooves 14 are contiguous with the main grooves 13 at the central pin 12; However, it is quite clear that the secondary grooves 14 and the main grooves 13 may not be contiguous at the central pin 12 without going out of the scope of the invention.

[0086] The distal end of each secondary groove 14 extends to a distance from the seat 8 of between 12% and 25% of the value of said seat diameter <1> A and, preferably, extends to a distance from the seat 8 of approximately 19% of the value of said seat diameter <1> A. Furthermore, the bottom of each secondary groove 14 has a curved radial profile such that the depth of each secondary groove 14 decreases from the central pin 12 to its distal end. The maximum depth of each secondary groove 14 is between 6% and 18% of the seat diameter. <1> A and, preferably, is equal to approximately 8% of the seat diameter <1> HAS.

[0087] Said radial radius of curvature R6 of the bottom of each secondary groove 14 is between 25% and 55% of the seat diameter <1> A and, preferably, is at 31.2% of said seat diameter <1> HAS.

[0088] Furthermore, the bottom of each secondary groove 14 has, in cross-section of said secondary groove 14, a curvilinear shape whose radius of curvature is constant or variable from the central pin 12 to its distal end.

[0089] Advantageously, the bottom of each secondary groove 14 has a variable width, such as a decreasing width, for example, from the central pin 12 to its distal end, the bottom having a width L3 at the central pin 12 and a width L4 at the distal end of the secondary groove 14. Said width L3 of the bottom of each secondary groove 14 is between 1 and 7% of the seat diameter. <1> A and, preferably, is equal to 3.5% of said seat diameter <1> A. Furthermore, the width L4 of the bottom of each secondary groove 14 is between 30% and 130% of the width L3 and, preferably, is equal to 80% of said width L3.

[0090] Furthermore, said vault 10 has a height Hv between 11% and 18% of the base diameter <1> A and the central pawl 12 has a diameter <e>Pu included between 15% and 25% of the seat diameter <1> A and the said central plinth 12 overhangs the vault 10 by a height Hpu between 9% and 18% of said bearing diameter <1> A and, preferably, with a height of 12.6% of said seat diameter <1> HAS.

[0091] Advantageously, the vault 10 has a substantially spherical shape of radius R centered on the longitudinal axis of the container 1, said radius R of the vault 10 being between 70% and 120% of the seat diameter <1> A and, preferably, said radius R of the vault 10 is equal to 86% of the base diameter <1> HAS.

[0092] Furthermore, the base of the central pin 12 consists of a spherical cap whose concavity is oriented towards the base 8 and whose radius of curvature RI is between 25% and 75% of the base diameter <1> A and, preferably, is equal to 50% of the seat diameter <1> A. Also advantageously, said central post 12, i.e. the lateral wall of said central post, is composed of at least three consecutive radii from its base to the arch 10. Preferably, the radius of curvature Rla of the lateral wall of the central post 12 is between 25% and 75% of the bearing diameter. <1> A and, preferably, is equal to 50% of said seat diameter <1> HAS.

[0093] Furthermore, the width p of the seat 8 is between 0.5% and 5% of the seat diameter <1> A and, preferably, said width p of the seat 8 is equal to 2.4% of the seat diameter <1> HAS.

[0094] According to a first embodiment of the container according to the invention, with reference to Figures 8 and 9, said container 1 comprises, in the same manner as before, a neck 2, provided with a spout 3, a shoulder 4 flaring out in the direction opposite to the neck 2, this shoulder 4 being extended by a lateral wall or body 5, generally substantially cylindrical in shape of revolution around a vertical longitudinal axis, shown in figures 8 and 9 and a bottom 6 which extends opposite the neck 2, from a lower end of the body 5.

[0095] Said base 6 comprises a peripheral heel 7 in the form of an annular ridge extending substantially axially in line with the body 5. The heel 7 terminates in a support 8, also called a base, perpendicular to the longitudinal axis of the container 1, said base 8 defining the lower end of the container 1 and enabling the container 1 to be placed vertically on a flat surface. Furthermore, said heel 7 extends up a wall called a connecting wall 9 with the wall of the body 5 of the container 1.

[0096] Note <1> A is the diameter of the base 8, the term "diameter" covering not only the case (illustrated) where the container 1 (and therefore the base 6) has a circular outline, but also the case where the container 1 would have a polygonal outline (for example square), in which case the term "diameter" would designate the diameter of the circle in which this polygon would be inscribed without going out of the scope of the invention.

[0097] Furthermore, the bottom 6 also includes a concave vault 10, in the form of a substantially spherical cap 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 10 extends from the heel 7 to a central area 11 of the bottom 6 forming a central pin 12 projecting towards the inside of the container 1, with in its center an amorphous pellet 13 which corresponds to the injection area 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.

[0098] Furthermore, with reference to Figures 8 and 9, said base 6 comprises a central pin 12 whose concavity is oriented towards the base 8, said vault 10 extending from the base of said central pin 12 to said heel 7, and the vault 10 comprises four main grooves 13 extending radially from the central pin 12 towards the base 8, the concavity of said main grooves 13 being oriented towards the base 8 and said main grooves 13 being angularly distributed around said central pin 12.

[0099] This embodiment differs from the one previously described in that the central pin 12 does not have a generally frustoconical or cylindrical lateral wall of revolution about the longitudinal axis of the container, but rather a substantially cylindrical or frustoconical wall having three lobes in cross-section. In other words, in this embodiment, the central pin 12 does not have a shape of revolution about the longitudinal axis of the container.

[0100] It is quite obvious that the central pawl 12 may have any shape whatsoever without going out of the scope of the invention.

[0101] Furthermore, in the same way as before, the vault 10 has four so-called secondary grooves 14 extending radially from the central pin 12 in direction of the seat 8 along a length less than that of the main grooves 13, the concavity of said secondary grooves 14 being oriented towards the seat 8 and said secondary grooves 14 being angularly distributed around said central pin 12 extending between two main grooves 13.

[0102] It is quite evident that the vault 10, the central pin 12, the main grooves 13 and the secondary grooves 14 in particular have the same characteristics as those described previously.

[0103] According to a second embodiment of the container according to the invention, with reference to Figures 10 to 12, said container 1 comprises, in the same way as before, a neck 2, provided with a mouth 3, a shoulder 4 flaring out in the direction opposite to the neck 2, this shoulder 4 being extended by a side wall or body 5, generally substantially cylindrical in shape of revolution about a vertical longitudinal axis, shown in Figures 8 and 9 and a bottom 6 which extends opposite to the neck 2, from a lower end of the body 5.

[0104] Said base 6 comprises a peripheral heel 7 in the form of an annular ridge extending substantially axially in line with the body 5. The heel 7 terminates in a support 8, also called a base, perpendicular to the longitudinal axis of the container 1, said base 8 defining the lower end of the container 1 and enabling the container 1 to be placed vertically on a flat surface. Furthermore, said heel 7 extends up a wall called a connecting wall 9 with the wall of the body 5 of the container 1.

[0105] We denote OA the diameter of the seat 8, the term "diameter" covering not only the case (illustrated) where the container 1 (and therefore the base 6) has a circular contour, but also the case where the container 1 would have a polygonal contour (for example square), in which case the term "diameter" would designate the diameter of the circle in which this polygon would be inscribed without going out of the scope of the invention.

[0106] Furthermore, the base 6 also includes a substantially concave vault 10. This embodiment differs from the embodiments previously described in that said vault 10 does not take the form of a substantially spherical cap 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, but rather takes the form of several cylindrical portions 10a, 10b whose diameter decreases from the heel 7 to the central zone 11, i.e., to the central pin 12. The vault 10 extends from the heel 7 to the central zone 11 of the bottom 6, forming a central pin 12 projecting inwards from the container 1, with at its center an amorphous pellet 13 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.

[0107] Furthermore, said base 6 comprises a central pin 12 whose concavity is oriented towards the course 8, said vault 10 extending from the base of said central pin 12 to said heel 7, and the vault 10 comprises four main grooves 13 extending radially from the central pin 12 towards the course 8, the concavity of said main grooves 13 being oriented towards the course 8 and said main grooves 13 being angularly distributed around said central pin 12.

[0108] In this embodiment, said central pin 12 has a lateral wall that is generally frustoconical or cylindrical of revolution around the longitudinal axis of the container 1; however, it is quite clear that said central pin 12 may have a substantially cylindrical or frustoconical wall having in straight section three lobes as described above, or any other shape whatsoever, without going out of the scope of the invention.

[0109] Furthermore, in the same way as before, the vault 10 has four so-called secondary grooves 14 extending radially from the central pin 12 towards the course 8 along a length less than that of the main grooves 13, the concavity of said secondary grooves 14 being oriented towards the course 8 and said secondary grooves 14 being angularly distributed around said central pin 12 extending between two main grooves 13.

[0110] It is quite evident that the vault 10, the central pin 12, the main grooves 13 and the secondary grooves 14 in particular have the same characteristics as those described previously.

[0111] With reference to [Fig. 13], 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.

[0112] Said molding unit 19, with reference to [Fig. 13], comprises a mold 20 having a lateral wall 21 that defines a cavity 22 in the shape of a portion of the container 1. Said mold 20 further comprises a base 23 in the shape of the base of the container 1, 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 1, extends along a principal axis that defines a vertical direction. Any plane perpendicular to the principal axis 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-cavity 24a, 24b of the body 5 of the container 1, and mounted in rotation relative to each other about 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 mold bottom 23 is lowered relative to the half-molds 20a, 20b to allow the introduction of the blank and the evacuation of the formed container 1, and a closed position, in which the half-. Molds 20a and 20b are placed against each other and enclose the mold base 23, as shown in Figures 6 to 8, thus forming the cavity 22 and defining the shape of the container 1 to be formed. This mold base 23 is therefore suitable for moving within the mold 20, which comprises two walls movable relative to each other and intended to form the body 5 of the container 1.

[0113] 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.< / e>

Claims

Demands

1. A plastic container (1) having a body (5) and a base (6) extending from a lower end of the body (5), said body (5) comprising at its upper end a shoulder (4) and a neck (2), and the base (6) comprising at least one peripheral heel (7) defining a seat (8), and an arch (10) extending from a central zone (11) to said heel (7), said heel (7) extending up a connecting wall (9) with the wall of the body (5) of the container (1), characterized in that said base (6) has at least one central pin (12) having a generally frustoconical lateral wall of revolution about the longitudinal axis X of the container (1) and whose concavity is oriented towards the seat (8), said arch (10) extending from said central pin (12) to said heel (7) and having a height between 11% and 18% of the seat diameter <1> HAS,and said central pin (12) having a diameter between 15% and 25% of the seat diameter <1> A and overhanging the vault (10) by a height between 9% and 18% of said bearing diameter <1> HAS.,

2. Container (1) according to claim 1 characterized in that the vault (10) has a substantially spherical shape of radius R centered on the longitudinal axis of the container (1), said radius R of the vault (10) being between 70% and 120% of the base diameter OA.

3. Container (1) according to claim 2 characterized in that said radius R of the arch (10) is equal to 86% of the seat diameter OA.

4. Container (1) according to any one of claims 1 to 3 characterized in that the bottom of the central pin (12) is made of a spherical cap whose concavity is oriented towards the seat (8) and whose radius of curvature is between 25% and 75% of the seat diameter OA.

5. Container (1) according to claim 4 characterized in that the radius of curvature of the bottom of the central pin (12) is equal to 50% of the seat diameter OA.

6. Container (1) according to any one of claims 1 to 5 characterized in that the central pin (12) is composed of at least three consecutive rays from its bottom to the arch (10).

7. Container (1) according to any one of claims 1 to 6 characterized in that the width p of the seat (8) is between 0.5% and 5% of the seat diameter OA.

8. Container (1) according to claim 7 characterized in that the width p of the seat (8) is equal to 2.4% of the seat diameter OA.

9. Container (1) according to any one of claims 1 to 8 characterized in that the vault (10) has between two and six main grooves (13) extending radially from the central pin (12) in the direction of the seat (8), the concavity of said main grooves (13) being oriented towards the seat plane and said main grooves (13) being angularly distributed around said central pin (12).

10. Container (1) according to claim 9 characterized in that the distal end of each main groove (13) extends to a distance from the seat (8) of between 8% and 20% of the value of said seat diameter OA.

11. Container (1) according to claim 10 characterized in that the distal end of each main groove (13) extends to a distance from the seat (8) of about 14% of the value of said seat diameter OA.

12. Container (1) according to any one of claims 9 to 11 characterized in that the bottom of each main groove (13) has a curved radial profile such that the depth of each main groove (13) decreases from the central pin (12) to its distal end.

13. Container (1) according to any one of claims 9 to 12 characterized in that the maximum depth of each main groove (13) is between 6% and 18% of the seat diameter OA.

14. Container (1) according to claim 13 characterized in that the maximum depth of each main groove (13) is about 8% of the seat diameter OA.

15. Container (1) according to any one of claims 12 to 14 characterized in that the radial radius of curvature R5 of the bottom of each main groove (13) is between 30% and 60% of the seat diameter OA.

16. Container (1) according to claim 15 characterized in that the radial radius of curvature R5 of the bottom of each main groove (13) is equal to 38.5% of the seat diameter OA.

17. Container (1) according to any one of claims 9 to 16 characterized in that the bottom of each main groove (13) has, in cross-section of said main groove (13), a curvilinear shape whose radius of curvature is variable from the central pin (12) to its distal end.

18. Container (1) according to claim 17 characterized in that said radius of curvature of the bottom of each main groove (13) is increasing from the central pin (12) to its distal end.

19. Container (1) according to claim 17 characterized in that said radius of curvature of the bottom of each main groove (13) is substantially constant from the central pin (12) to a distance of about 40% of the total length of the main groove (13), representing a first section of the main groove (13), and said radius of curvature of the bottom of each main groove (13) is increasing from the end of said first section to the distal end of the main groove (13).

20. Container (1) according to claim 19 characterized in that the bottom of each main groove (13) has a substantially constant width L1 from the central pin (12) to a distance of about 40% of the total length of the main groove (13), i.e. in the first section of the main groove (13), and an increasing width L2 from the end of said first section to the distal end of the main groove (13).

21. Container (1) according to claim 20 characterized in that the width L1 in the first section of each main groove (13) is between 1% and 6% of the seat diameter OA, and preferably equal to 3% of said seat diameter OA.

22. Container (1) according to any one of claims 20 or 21 characterized in that the width L2, between the end of the first section and the distal end of the main groove (13), is between 200% and 700% of the width L1 and, preferably, equal to 393% of said width L1.

23. Container (1) according to any one of claims 9 to 22 characterized in that the vault (10) comprises between two and six so-called secondary grooves (14) extending radially from the central pin (12) in the direction of the seat (8) along a length less than that of the main grooves (13), the concavity of said secondary grooves (14) being oriented towards the seat plane and said secondary grooves (14) being angularly distributed around said central pin (12) extending between two main grooves (13).

24. Container (1) according to claim 23 characterized in that the distal end of each secondary groove (14) extends to a distance from the seat (8) of between 12% and 25% of the value of said seat diameter OA.

25. Container (1) according to claim 24 characterized in that the distal end of each secondary groove (14) extends to a distance from the seat (8) of about 19% of the value of said seat diameter OA.

26. Container (1) according to any one of claims 23 to 25 characterized in that the bottom of each secondary groove (14) has a curved radial profile such that the depth of each secondary groove (14) decreases from the central pin (12) to its distal end.

27. ​​Container (1) according to claim 26 characterized in that the radial radius of curvature R6 of the bottom of each secondary groove (14) is between 25% and 55% of the seat diameter OA.

28. Container (1) according to any one of claims 23 to 27 characterized in that the maximum depth of each secondary groove (14) is between 6% and 18% of the seat diameter OA.

29. Container (1) according to claim 28 characterized in that the maximum depth of each secondary groove (14) is about 8% of the seat diameter OA.

30. Container (1) according to any one of claims 27 to 29 characterized in that the radial radius of curvature R6 of the bottom of each secondary groove (14) is equal to 31.2% of the seat diameter OA.

31. Container (1) according to any one of claims 23 to 30 characterized in that the bottom of each secondary groove (14) has, in cross-section of said secondary groove (14), a curvilinear shape whose radius of curvature is constant or variable from the central pin (12) to its distal end.

32. Container (1) according to claim 31 characterized in that the bottom of each secondary groove (14) has a decreasing width from the central pin (12) to its distal end, the bottom having a width L3 at the central pin (12) and a width L4 at the distal end of the secondary groove (14).

33. Container (1) according to claim 32 characterized in that the width L3 of the bottom of each secondary groove (14) is between 1 and 7% of the seat diameter <1> A and, preferably, is equal to 3.5% of said seat diameter <1> HAS.

34. Container according to any one of claims 32 or 33 characterized in that the width L4 of the bottom of each secondary groove (14) is between 30% and 130% of the width L3 and, preferably, is equal to 80% of the width L3.

35. 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 (5) of the container (1), said mold base (23) comprising at least a first annular part intended to form at least in part the heel (7) of the container (1), i.e. the seating surface, a second dome-shaped part intended to come into contact with an amorphous central area of ​​the preform to form the arch (10) of the bottom (6) of the container (1), characterized in that said second part is arranged so as to produce a container comprising a bottom (6) according to any one of claims 1 to 34.