EP3059175B1 - Container provided with a mini petaloid bottom with transverse corrugations - Google Patents

Description

The invention relates to the field of containers, especially bottles or jars, manufactured by blow molding or stretch blow molding from preforms or intermediate containers of plastics material such as polyethylene terephthalate (PET).

A container generally comprises an open neck, through which the contents (usually a liquid) are introduced and by which the latter is emptied, a body which gives the container its volume, and a bottom which closes the body opposite the collar and forms a base for holding and maintaining the container when it rests on a support such as a table.

Containers with petaloid-shaped bottoms are known, which include projecting, petal-shaped legs separated by convex wall portions, called valleys or valleys, which extend radially from a central zone of the bottom. The feet are intended to ensure the stable holding of the container on a support; the valleys are designed to absorb the forces (thermal and / or mechanical) exerted by the contents.

The petaloid bottoms of high height (that is to say whose feet have a height in a ratio with the container diameter greater than or equal to 1/2) have a high mechanical strength; this is particularly suitable for carbonated liquids (in other words for soft drinks) generating pressures greater than 2.5 bar. An illustrative example of this type of substance can be found in the international application WO 2012/069759 (SIDEL).

But the petaloid bottoms of this type consume a large amount of material (a container of 0.5 l with a classic petaloid base has a mass of the order of - or greater than - about 18 g).

Attempts have been made to adapt petaloid bottoms to flat liquids (eg still water) or slightly gaseous (generating internal pressure less than or equal to 2.5 bar), or to liquids under slight pressure (from in the order of 0.3 bar to 1 bar) by means of a neutral gas (such as nitrogen). To limit the amount of material required to make a petaloid bottom, the height of the bottom has been reduced, and the bottom has been reinforced, in the valleys, by means of grooves straddling a central dome. This technique, illustrated in international application WO 2014/207331 (SIDEL), has proven itself and allowed to reduce the amount of material to about 10g for a container with a capacity of 0.5 l. But the constraints in terms of material economy are getting tougher, and today manufacturers are asked to reduce the weight of the containers by an additional 10 to 20% (ie a mass in the range of 8g to 9g for a container with a capacity of 0.5 l).

Under these conditions, the known forms cease to be relevant and new solutions must be found to maintain or increase, at reduced mass, the rigidity of the bottom of the containers.

In particular, it was noted that by lightening the petaloid background by 15% of the type described in the application WO 2014/207331 above, this bottom deforms under an internal pressure greater than or equal to 0.5 bar. More specifically, folds appear uncontrollably in the valleys, which weakens the bottom of the container and makes it risky stacking (and therefore its palletization). The document FR 2974069 A1 also discloses a plastic container as described in the preamble of claim 1. Finally, the document JP H06 156464 A discloses a plastic container having legs provided with flutes extending in a circumferential direction.

An object is therefore to provide a container whose bottom has good mechanical strength despite a reduced amount of material, and which can in particular withstand stacking to be palletized safely.

For this purpose, there is provided a plastic container comprising a body and a petaloid bottom having a periphery through which it connects to the body, the bottom comprising a bottom wall of generally convex shape towards the outside of the container, which project feet formed by excrescences, separated in pairs by portions of the bottom wall forming recessed valleys which extend radially to the periphery of the bottom, the bottom further comprising, in each valley, in the vicinity of the periphery of the bottom, at least one groove which extends transversely with respect to the radial direction of extension of the valley.

These grooves make it possible to control, by absorbing them, the deformations due to the pressure prevailing in the container, which in particular avoids the unexpected formation of folds in the valleys, and gives the bottom a good mechanical resistance which allows the container to be stacked. (and therefore palletized).

• chaque cannelure s'étend d'un bord à l'autre de la vallée ;
• chaque cannelure présente un creux central ayant, en section radiale, une forme en arc de cercle à concavité tournée vers l'extérieur du récipient et des congés de raccordement qui bordent le creux central et ont en section radiale une forme en arc de cercle à concavité tournée vers l'intérieur du récipient ;
• la cannelure présente une profondeur comprise entre 0,8 mm et 1,5 mm ;
• le fond comprend au moins deux cannelures adjacentes, à savoir une cannelure principale et au moins une cannelure secondaire décalée de la cannelure principale vers le centre du fond ;
• la cannelure secondaire présente une longueur, mesurée transversalement, inférieure à celle de la cannelure principale ;
• le fond présentant un diamètre hors tout D1, les pieds définissent un plan de pose ayant un diamètre D2 tel que : $$0,67\cdot D1\le \mathrm{<figure-callout\; id="2"\; label="D"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">D</figure-callout>}2\le 0,72\cdot D1$$
  
• le fond présente une hauteur totale H1 telle que : $$0,25\cdot D1\le H1\le 0,28\cdot D1$$
  
• le fond présente une région centrale et une région périphérique concentriques séparées par un décrochement continu chevauchant les pieds et les vallées ;
• chaque pied est pourvu d'une rainure qui s'étend axialement et chevauche un sommet du pied.

Various additional features may be provided, alone or in combination:

• each groove extends from one side to the other of the valley;
• each groove has a central hollow having, in radial section, a concave arcuate shape facing outwardly of the container and connecting fillets which border the central recess and have in radial section a concave arcuate shape turned towards the inside of the container;
• the groove has a depth of between 0.8 mm and 1.5 mm;
• the bottom comprises at least two adjacent flutes, namely a main flute and at least one secondary flute offset from the main flute towards the center of the bottom;
• the secondary groove has a length, measured transversely, less than that of the main groove;
• the bottom having an overall diameter D1, the feet define a laying plane having a diameter D2 such that: $$0,67\cdot D1\le \mathrm{<figure-callout\; id="2"\; label="D"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">D</figure-callout>}2\le 0,72\cdot D1$$
  
• the bottom has a total height H1 such that: $$0,25\cdot D1\le H1\le 0,28\cdot D1$$
  
• the bottom has a central region and a concentric peripheral region separated by a continuous step overlapping the feet and the valleys;
• each foot is provided with a groove which extends axially and overlaps a top of the foot.

• la figure 1 est une vue en perspective, de dessous, d'un récipient muni d'un fond pétaloïde ;
• la figure 2 est une vue de détail, à échelle agrandie, du fond du récipient de la figure 1 ;
• la figure 3 est une vue de détail, de côté, du fond de la figure 2 ;
• la figure 4 est une vue de dessous, à échelle agrandie, du fond des figures 2 et 3 ;
• la figure 5 est une section du fond de la figure 4, selon le plan de coupe V-V, avec en médaillon un détail à échelle agrandie ;
• la figure 6 est une vue du détail en médaillon de la figure 5, dans laquelle la matière est déformée sous l'effet de la pression régnant dans le récipient rempli ;
• la figure 7 est une vue de détail en coupe du fond de la figure 4, selon le plan de coupe VII-VII.

Other objects and advantages of the invention will become apparent in the light of the description of an embodiment, given hereinafter with reference to the accompanying drawings, in which:

• the figure 1 is a perspective view, from below, of a container with a petaloid bottom;
• the figure 2 is a detail view, on an enlarged scale, of the bottom of the container of the figure 1 ;
• the figure 3 is a detail view, from the side, from the bottom of the figure 2 ;
• the figure 4 is a bottom view, on an enlarged scale, of the bottom of figures 2 and 3 ;
• the figure 5 is a section of the bottom of the figure 4 according to the sectional plan VV, with a medallion detail on an enlarged scale;
• the figure 6 is an inset detail view of the figure 5 wherein the material is deformed under the effect of the pressure in the filled container;
• the figure 7 is a detailed sectional view of the bottom of the figure 4 according to the section plane VII-VII.

On the figure 1 is shown, in perspective from below, a container 1 - in this case a bottle - obtained by blow molding or stretch blow from a preform of thermoplastic material, for example polyethylene terephthalate (PET), previously heated.

The container 1 extends along a main axis X and comprises a side wall called body 2, and a bottom 3 which extends and closes the body 2 at a lower end thereof.

The bottom 3 is petaloid, and comprises a bottom wall 4 of generally convex shape towards the outside of the container 1 (that is to say down when the container 1 is laid flat). This wall 4 extends from a central dome 5 concavity turned towards the outside of the container 1. In the center of the dome 5 extends in axial projection a pellet 6 injection coming, whose material has remained substantially during the forming of the container 1. The dome 5 has the particular function of stretching the material in the center of the bottom 3, so as to increase the crystallinity and therefore the mechanical strength.

The bottom 3 also comprises a series of feet 7 formed by protrusions projecting axially from the bottom wall 4 towards the outside of the container 1. The feet 7 extend radially from the central dome 5 , at a periphery 8 of the bottom 3 by which it connects to the body 2. D1 denotes the overall radial extension of the bottom 3, measured perpendicular to the axis X at its periphery 8 ( figure 5 ). In the case of a receptacle 1 with a cylindrical body 2 (as in the example illustrated), the radial extension D1 is its diameter.

The more protrusions or peaks 9 feet 7 together form a plane 10 of pose by which the container 1 can rest on a flat surface (e.g. a table). As is visible on the figure 3 , The plane 10 of pose is radially set back relative to the periphery 8. Note the radial extension D2 (that is to say, in the illustrated example, the diameter) of the plane 10 of pose, and H1 the total height of the base 3 (which corresponds to that of the feet 7), measured axially from the plane of installation 10 to the periphery 8 of the base 3.

The total height H1 of the bottom is advantageously between 25% and 28% of the overall radial extension D1 of the bottom 3: $$0,25\cdot D1\le H1\le 0,28\cdot D1$$

A classic petaloid background would have a H1 / D1 ratio of about 0.5. The present bottom 3, which may be called "mini petaloid" because of its low ratio H1 / D1, limits the amount of material necessary for the formation of the bottom 3 while allowing it, thanks to its petaloid structure , to host content under pressure.

Among this type of content, let us mention the flat liquids associated with the addition, immediately after filling and before capping, of a drop of liquid nitrogen whose vaporization puts the contents of the container under an overpressure, or even slightly carbonated drinks. (like some faintly sparkling waters). The relative pressure (that is to say the part of the absolute pressure greater than the atmospheric pressure) in the container 1 is, depending on the type of content, between 0.3 bar and 2.5 bar.

Moreover, the radial extension D2 of the map 10 of poses is preferably between 67% and 72% of the radial extension D1 overall bottom 3: $$0,67\cdot D1\le \mathrm{<figure-callout\; id="2"\; label="D"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">D</figure-callout>}2\le 0,72\cdot D1$$

This dimensional ratio offers a good compromise between the stability of the bottom 3 (which increases according to the ratio D2 / D1) and its blowing (that is to say, its ability to be properly formed by blowing), which, conversely, decreases according to the ratio D2 / D1.

As is clearly visible on the Figures 2 to 4 the feet 7 will taper from the inside to the outside of the container 1 (i.e. from the top to the bottom), and widening from the central dome 5 to the periphery 8.

Each foot 7 has an end face 11 which extends gently from the dome 5 to the apex 9 and which, as can be seen in FIGS. figures 2 and 5 , has a slightly increasing width from the vicinity of the dome 5 to the periphery 8.

Note H2 the axial extension of the end face 11 (also called arrow or bottom guard 3 ), measured between the laying plane 10 and the edge of the dome 5. The arrow H2 is less than the height H1 from the bottom 3, but without being negligible with respect thereto. More precisely, the arrow H2 is between 28% and 32% of the height H1 of the bottom 3: $$0,28\cdot H1\le \mathrm{<figure-callout\; id="2"\; label="H"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">H</figure-callout>}2\le 0,32\cdot H1$$

The relatively low H2 / H1 ratio offers, again, a good compromise between the mechanical resistance of the bottom (which increases as a function of the H2 / H1 ratio) and its blowing (which conversely decreases with the H2 / H1 ratio).

According to a preferred embodiment, illustrated in the figures, the arrow H2 is approximately 31% of the height H1 of the bottom 3: $$\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">H</figure-callout>}2\cong 0,31\cdot H1$$

Note also H3 the depth, measured axially, of the dome 5. This depth H3 is preferably between 2 mm and 3 mm: $$2\mathit{mm}\le \mathrm{<figure-callout\; id="3"\; label="H"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">H</figure-callout>}3\le 3\mathit{mm}$$

For a container with a capacity of 0.5 l, having an overall diameter D 1 of the order of 65 mm, the depth H 3 of the dome is relatively large and makes it possible to stretch the material in the center of the bottom 3, which increases its structural rigidity and thus its mechanical strength.

As is clearly visible on the figures 2 , 3 and 4 , the feet 7 are separated in pairs by portions 12 of the bottom wall 4 called valleys, which extend radially in a star from the dome 5 to the periphery 8.

The valleys 12 extend in hollow between the feet 7 which they separate two by two. The valleys 12 have, in cross section (that is to say in a plane perpendicular to the radial direction, see the figure 7 ), a U-shaped profile that can go flaring from the inside to the outside of the container (that is to say downwards).

According to a particular embodiment illustrated on the figures 2 and 4 the valleys 12 do not connect directly to the dome 5 but terminate internally at an inner end 13 away from the dome 5, an intermediate space 14 being thus defined between the end 13 and an outer edge 15 of the dome 5.

As we see on the figures 2 and 4 the feet 7 are equal in number to the valleys 12. In the example shown, the bottom 3 comprises five feet 7 and five valleys 12, regularly alternated and distributed in a star. This number is a good compromise; it could however be less (but greater than or equal to three), or greater (but preferably less than or equal to nine).

• au voisinage de la vallée 12, une première ouverture A1 angulaire,
• au voisinage du sommet 9, une deuxième ouverture A2 angulaire, de préférence inférieure ou égale à la première ouverture A1 angulaire : $$A2\le A1$$
  

Each foot 7 has two flanks 16 which each border laterally a valley 12. As can be seen on the figure 2 , and as we see on the figure 7 the flanks 16 are not vertical (because the bottom 3 would be difficult or impossible to blow), but inclined opening from the valley 12 to the outside. The angular aperture between the flanks 16 is not necessarily constant according to the distance to the valley 12. Thus, according to an embodiment illustrated in FIG. figure 7 , each flank 16 has, substantially at mid-height of the foot, a slope break, so that are defined between the flanks 16 which face each other:

• in the vicinity of the valley 12, a first angular aperture A1 ,
• in the vicinity of the apex 9, a second angular aperture A2 , preferably less than or equal to the first angular aperture A1 : $$\mathrm{AT}2\le \mathrm{AT}1$$
  

The first angular aperture A1 is advantageously between 45 ° and 55 °: $$45°\le \mathrm{AT}1\le 55°$$

According to a preferred embodiment, the first angular aperture A1 is about 50 °: $$\mathrm{AT}1\cong 50°$$

Moreover, the second angular aperture A2 is advantageously between 15 ° and 21 °: $$15°\le \mathrm{AT}1\le 21°$$

According to a preferred embodiment, the second angular aperture A2 is approximately 18 °: $$\mathrm{AT}2\cong 18°$$

The first angular aperture A1 which is quite large improves the blowing of the bottom 3. The second angular aperture A2 , which is smaller, increases the stability of the bottom 3 by imparting a certain verticality to the feet 7, on the side of their apex 9.

The pressurization of the container 1 is capable of deforming the bottom 3. In order to limit these deformations, the bottom 3 is provided, in each valley 12, in the vicinity of the periphery 8 (that is to say in the vicinity of the junction between the valley 12 and the body 2 ), at least one groove 17 which extends transversely to the direction radial extension of the valley 12.

This groove 17 forms in the valley 12 a hollow towards the interior of the container 1. The groove 17 has a tapered grain-rice shape and is wider (measured radially) in the center of the valley 12 than at the edges of the valley. this. For better visibility we have, on the figures 2 and 4 , grayed flutes 17 by a dot pattern.

As we see on the figures 2 and 4 each groove 17 may have a length (when measured transversely) greater than the width of the valley 12, and therefore encroach, at its lateral ends, on the flanks 16 of the feet 7 bordering the valley 12.

• un creux central ayant, en section radiale, une forme en arc de cercle à concavité tournée vers l'extérieur du récipient 1 et dont le rayon est noté R1, et
• des congés de raccordement qui bordent le creux central et ont également, en section radiale, une forme en arc de cercle à concavité tournée vers l'intérieur du récipient 1 et dont le rayon est noté R2.

The flute 17 forms a ripple in the valley 12, and comprises:

• a central hollow having, in radial section, a concave circular arc shape facing outwardly of the container 1 and having a radius R1, and
• connecting fillets which border the central recess and also have, in radial section, a concave arcuate shape turned towards the interior of the container 1 and whose radius is denoted R2.

The depth of the groove 17 is relatively small, being between 0.8 mm and 1.5 mm. According to a particular embodiment, the depth of the groove 17 is about 1 mm.

According to an embodiment illustrated in the figures, the bottom 3 comprises in each valley 12 at least two adjacent flutes, namely a first groove 17, said main, and a second groove 18, said secondary, adjacent the main groove 17 . The secondary groove 18 is offset from the main groove 17 towards the center of the bottom 3 and also extends transversely from one edge to the other of the valley 12, although being shorter (measured transversely) than the main groove 17 . So, as we see on the example of figures 2 and 4 , the secondary groove 18 encroaches only slightly, at its lateral ends, on the flanks 16 of the feet 7.

Like the main groove 17 , the secondary groove 18 has a tapered rice grain shape being wider (measured radially) in the center of the valley 12 than at the edges thereof. On the figures 2 and 4 it has also dimmed the grooves 18 side by a dot pattern.

• un creux central ayant, en section radiale, une forme en arc de cercle à concavité tournée vers l'extérieur du récipient 1 et de même rayon R1 que la cannelure 17 principale, et
• des congés de raccordement qui bordent le creux central et ont également, en section radiale, une forme en arc de cercle à concavité tournée vers l'intérieur du récipient 1 et de même rayon R2 que celui des congés de raccordement de la cannelure 17 principale.

Likewise, the secondary groove 18 forms a corrugation in the valley 12, and comprises:

• a central hollow having, in radial section, a concavity-shaped arcuate shape facing towards the outside of the container 1 and having the same radius R1 as the main spline 17 , and
• connecting fillets which border the central recess and also have, in radial section, a concave arcuate shape facing the interior of the container 1 and of the same radius R2 as that of the connecting fillet 17 of the main groove.

The radius R1 of the central hollow of each groove 17, 18 is between 0.3 mm and 1 mm. According to a particular embodiment, the radius R1 is approximately 0.5 mm.

The radius R2 of the fillet of each spline 17, 18 is greater than the radius R1 of the central hollow. This radius R2 is between 1.2 mm and 1.8 mm. According to a particular embodiment, the radius R2 is about 1.5 mm.

Like the main groove 17 , the secondary groove 18 has a relatively small depth, between 0.8 mm and 1.5 mm. According to a particular embodiment, the depth of the secondary groove 18 is about 1 mm.

When the container 1 is pressurized, the deformations due to the stresses to which the bottom is subjected are localized on the main splines 17 (and secondary grooves 18 when they exist), which deform by flattening, as shown in FIG. figure 6 , which avoids any pinching of the valley 12, in particular at its junction with the body 2 of the container 1. This results in a better mechanical strength of the bottom 3, which gives the container 1 a better rigidity and allows its stacking (and therefore its palletization) without risk of collapse.

The presence of secondary grooves 18 increases the capacity of the bottom 3 to absorb larger deformations, especially when the pressure in the container is relatively high (between 1 bar and 2.5 bars).

The number of secondary grooves 18 present in each valley 12 may be greater than one, that is to say that there may be a total of a number of splines 17, 18 (main and secondary) at least equal to two in each valley 12, depending on the deformation to which the container 1 is supposed to resist (and therefore the pressure in it).

According to a preferred embodiment, the bottom 3 has two concentric regions, namely an annular central region 19 surrounding the dome 5, and an annular peripheral region 20 surrounding the central region 19 , separated by a recess 21 which extends axially on a height H4 (measured axially) predetermined. The recess 21 is median with respect to the bottom 3, that is to say that it has a diameter, denoted D3, between 45% and 55% of the overall diameter D1 of the bottom 3: $$0,45\cdot D1\le \mathrm{<figure-callout\; id="3"\; label="D"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">D</figure-callout>}3\le 0,55\cdot D1$$

And, preferably, the diameter D3 of the recess 21 is equal to about half of the overall diameter D1 of the bottom 3: $$\mathrm{<figure-callout\; id="3"\; label="D"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">D</figure-callout>}3\cong 0,5\cdot D1$$

The recess 21 extends continuously around the dome 5, and overlaps both the feet 7 (including the flanks 16 ) and the valleys 12.

By the presence of recess 21, axial, the central region 19 is slightly raised relative to the peripheral region 20, being offset towards the interior of the container 1.

The height H4 of the recess 21 is substantially constant over its contour, advantageously being between 0.5 mm and 1.5 mm. For a container with a capacity of 0.5 liter (which corresponds to the example shown), the height H4 of the recess is about 1 mm.

The recess 21 serves to maintain the stability of the container 1 under relatively high pressure conditions (between 1 bar and 2.5 bars), by opposing the inversion of the bottom 3 and by contributing, under the internal pressure of the container, expand the plan 10 installation, which increases the stability of the container 1.

A3 denotes the angular aperture, measured around the axis X of the container 1 in a plane perpendicular to the axis X, of the part top of the feet 9, that is to say without counting the flanks 16, and A4 the angular aperture defined between the top parts of two consecutive feet 7 , that is to say the portion of the bottom 3 including a valley 12 and flanks 16 which border it (cf. figure 4 ). According to a preferred embodiment, the angular openings A3, A4 are substantially identical (variations of a few degrees may exist): $$\mathrm{AT}3\cong \mathrm{<figure-callout\; id="4"\; label="AT"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">AT</figure-callout>}4$$

As a result, in combination with the values indicated above, angular openings A1, A2 defined transversely between the flanks 16, a good compromise between the mechanical performance of the bottom 3 (that is to say the capacity of the latter). ci to resist the deformations and, when they occur, to undergo them in a controlled manner) and its blowing (that is to say the capacity of the bottom 3 to be properly formed by blowing).

The value of the openings A3, angular A4 therefore depends on the number of feet 7 (or the number of valleys 12, equal to the number of feet). More precisely, if N is the number of feet, then the openings A3 and A4, measured in degrees, are calculated as follows: $$\mathrm{AT}3\cong \mathrm{AT}4\cong \frac{360°}{2\mathrm{NOT}}$$

Thus, when the bottom comprises five feet 7, as in the illustrated case, the openings A3, A4 angular are about 36 °.

Moreover, as can be seen from the figures 3 and 5 , the vertices 9 of the feet are rounded, and have, in a radial plane, a radius R3 which is between 8% and 12% of the overall diameter D1 of the bottom 3: $$0,08\cdot D1\le \mathrm{<figure-callout\; id="3"\; label="R"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">R</figure-callout>}3\le 0,12\cdot D1$$

According to a preferred embodiment, the radius R3 of the vertex 9 of the feet 7 is equal to about one-tenth of the diameter D1 of the bottom 3: $$\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">R</figure-callout>}3\cong 0,1\cdot D1$$

This dimensioning ensures a good blowing bottom 3 while giving it good stability.

Each foot 7 can be connected to the body 2 by a flat face. However, according to a preferred embodiment illustrated on the figure 5 each foot 7 is connected to the body 2 by a curved face, having a radius R4 between 1/3 and half of the diameter D1 overall of the bottom 3 : $$\frac{D1}{3}\le \mathrm{<figure-callout\; id="4"\; label="R"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">R</figure-callout>}4\le \frac{D1}{2}$$

According to a preferred embodiment, the radius R4 of the connecting face of the feet 7 to the body 2 is of the order of 40% of the diameter D1 overall of the bottom 3: $$\mathrm{<figure-callout\; id="4"\; label="R"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">R</figure-callout>}4\cong 0,4\cdot D1$$

This dimensional ratio contributes to the good blowing of the bottom 3, without impairing its stability.

In addition, according to an advantageous embodiment illustrated in the drawings, each foot 7 is provided with a groove 22 formed in the hollow, which extends radially overlapping the top 9 (and therefore the plane 10 setting).

The grooves 22 have the function of stiffening the bottom 3. Under the effect of the mechanical stresses exerted on the container 1 (in particular under the effect of the pressure prevailing therein), the grooves 22 have a tendency to flow when they expand. and flattening, which causes a widening of the feet 7 at their apex 9 and gives the flanks 16 a certain verticality which opposes the overall subsidence of the bottom 3.

As we see on the figures 2 , 3 and 4 , each groove 22 has, on the side of its junction with the body 2, an enlarged end zone 23 which promotes the blowing and limits the risk of appearance of wrinkles during pressurization.

Finally, as we see on figures 2 , 3 , 4 and 7 each foot 7 comprises facets 24 which adjoin laterally (that is to say transversely to a radial direction) the vertices 9 of each foot.

According to an exemplary embodiment illustrated in the figures, each foot 7 is provided with a pair of facets 24. These facets 24, of substantially circular or oval contour, make it possible to save the quantity of material required to form the bottom 3 while stiffening the feet 7 and thus the bottom 3 ).

Claims (10)

1. Container (1) made of plastic material and comprising a body (2) and a petaloid base (3) having a periphery via which it is connected to the body (2), the base (3) comprising a base wall (4) that is generally convex towards the exterior of the container (1) and whence project feet (7) which are formed by excrescences any two of which being separated by portions of the base wall (4) forming recessed valleys (12) that extend radially to the periphery (8) of the base (3), characterized in that the base (3) further comprises, in each valley (12) and close to the periphery (8) of the base (3), at least one corrugation (17, 18) which extends transversely with respect to the direction of radial extent of the valley (12).
2. Container (1) according to Claim 1, characterized in that the corrugation (17, 18) extends from one edge of the valley (12) to the other.
3. Container (1) according to Claim 1 or Claim 2, characterized in that the corrugation (17, 18) has a central recess which, in radial section, is in the form of an arc of a circle that is concave towards the exterior of the container, and connecting fillets which bound the central recess and which, in radial section, are in the form of an arc of a circle that is concave towards the interior of the container.
4. Container (1) according to one of the preceding claims, characterized in that the corrugation (17, 18) has a depth of between 0.8 mm and 1.5 mm.
5. Container (1) according to one of the preceding claims, characterized in that the base (3) comprises at least two adjacent corrugations (17, 18), to wit a main corrugation (17) and at least one secondary corrugation (18) that is removed from the main corrugation (17) towards the centre of the base (3).
6. Container (1) according to Claim 5, characterized in that the length of the secondary corrugation (18), measured transversely, is less than that of the main corrugation (17).
7. Container (1) according to one of the preceding claims, characterized in that, the base (3) having an overall diameter D1, the feet (7) define a resting plane (10) of diameter D2, such that: $$\mathit{0.667}\cdot \mathit{D}\mathit{1}\le \mathit{D}\mathit{2}\le \mathit{0.72}\cdot \mathit{D}\mathit{1}$$

   
8. Container (1) according to one of the preceding claims, characterized in that the base (3) has an overall diameter D1 and a total height H1, such that: $$\mathit{0.25}\cdot \mathit{D}\mathit{1}\le \mathit{H}\mathit{1}\cdot \mathit{0.28}\cdot \mathit{D}\mathit{1}$$

   
9. Container (1) according to one of the preceding claims, characterized in that the base (3) has a central region (19) and a peripheral region (20) that are concentric and are separated by a continuous shoulder (21) which straddles the feet (7) and the valleys (12).
10. Container (1) according to one of the preceding claims, characterized in that each foot (7) is provided with a groove (22) which extends axially and straddles an apex (9) of the foot (7).

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