Mold base for manufacturing a container comprising an arched base with reinforcing projections

Abstract

This invention relates to a mold bottom for manufacturing a container from a plastic material, the container having a body and a bottom, the container bottom having: a base forming a placement plane of the container; a recessed dome; and reinforcing protrusions protruding from the recessed dome and extending radially within the dome, characterized in that the mold bottom comprises: - a first annular portion for at least partially forming the base; - a dome-shaped second portion for contacting the amorphous central region of the preform to form the dome, such that the reinforcing protrusions are angularly spaced from each other by alternating first and second protrusions distributed along a first and a third annular strip; the second portion carrying: - a protruding first annular strip for forming a first protrusion adjacent to the base, and - a protruding second annular strip for forming a second protrusion adjacent to the amorphous central region.

Description

[0001] This application is a divisional application of the invention patent application entitled "Container including an arched bottom with reinforcing protrusions distributed in an interlaced annular stripe pattern", filed on January 18, 2019, with national application number "201910045941.X". Technical Field

[0002] The field of this invention is the design and manufacture of containers made of plastic materials.

[0003] More precisely, the present invention relates to containers obtained by blow blowing or stretch blowing of preforms (preforms or intermediate containers subjected to one or more pre-blowing operations) made of plastic material. Background Technology

[0004] Manufacturing containers by blow molding involves introducing a preform, preheated to a temperature greater than the glass transition temperature of the preform's constituent material (such as PET), into a mold having a cavity for the container, and injecting pressurized fluid (such as air) into the preform. Blowing is accomplished by stretching via a slide bar.

[0005] This technique has been known for a long time. It is also recognized that the bimolecular orientation (axial and radial) experienced by the material during blow or stretch blow is sometimes too weak to definitively impart sufficient mechanical strength to the container. This lack of mechanical strength particularly affects the bottom of the container, which is subjected to significant dynamic (when filled) and static (after filling, by the pressure of the contents or as a result of stacking) constraints.

[0006] It is known to reinforce the bottom of a container by giving it a hollow shape, which defines a vault for bearing the aforementioned constraints. The mere presence of such a vault may not be sufficient, and it has even been proposed to reinforce the vault by radial ribs formed by localized material overthickness, as described, for example, in U.S. Patent document published under number US 4,525,401.

[0007] However, this structure assumes that the extra-thick additional material generated by the ribs is given to the bottom.

[0008] On the one hand, this leads to an increase in the weight of containers, which is clearly contrary to the current trend of material conservation.

[0009] On the other hand, this leads to blow forming difficulties (the ability to blow form a container is called "blowability," which is the ability of material to fit properly into the cavity of the model), because the material thickness makes it difficult to distribute the material through creep in the cavity of the corresponding rib of the model.

[0010] To overcome this problem, a common solution is to increase the blowing pressure, but this solution requires adjusting the pneumatic injection circuit's ability to rise, thus compromising the energy balance of the manufacturing process.

[0011] Furthermore, the potential difficulty in controlling material creep can cause all ribs to exhibit the same characteristics, particularly in terms of mechanical strength. This poses a risk of container bottom deformation, which, once filled and sealed, can lead to a lack of stability at the container's bottom.

[0012] Another solution involves pushing the constituent material of the container's bottom, for which a specific model is used, particularly equipped with a translationally movable model bottom for pushing the material (see European Patent Document EP 1 069 983). Pushing causes an increase in the material's deformation rate and thus a mechanical increase in its crystallinity; the pushing stage gives the container's bottom its final shape.

[0013] However, this technique, known as "boxage," does not guarantee sufficient rigidity at the bottom and does not exempt manufacturers from certain forms that are still subject to blow molding limitations.

[0014] Therefore, there is a need to continuously develop shapes that can provide a good trade-off between controlling material quantity, blowability and structural rigidity (especially for resisting deformation caused by overpressure in the container, typically when the contents are beverages).

[0015] The patent document published in the applicant's name under number WO 2013 / 156710 is intended to specifically meet this need. For example... Figure 1 As shown above, the document proposes a container that includes a bottom 1 with a dome 2, the dome 2 having a star-shaped profile 3 in cross-section.

[0016] The star-shaped outline 3 is obtained as follows:

[0017] - The angles of short branch 4 and long branch 5 alternate, with long branch 5 terminating close to the base 6 of the container, while short branch 4 is away from the base 6.

[0018] - Multiple facets 7 connect short branches 4 to long branches 5 that are adjacent to each other.

[0019] In the inventor's view, this type of container offers excellent performance while being perfect, especially in terms of the perception that end users may have.

[0020] The end-user's perception here is understood as perception from both technical and aesthetic perspectives.

[0021] From a technical point of view, the proximity of the long branch 5 to the base 6 may lead to manufacturing difficulties.

[0022] In fact, there are risks involved in blowing containers:

[0023] -Or the material cannot flow properly into the model.

[0024] -Or the appropriate flow of material exits from its predetermined molding position.

[0025] This phenomenon is particularly noticeable in the area separating the star-shaped profile 3 from the base 6. This area can actually promote insufficient creep or material shedding to a very small extent. This can lead to deformation in this area, and thus increase the risk of instability in the container or simply result in visual defects.

[0026] In other words, in this case, the base 6 can be generally corrugated, thus defining a continuous placement plane, but the placement sections may not be completely coplanar, which would therefore affect the good stability of the container. Summary of the Invention

[0027] The main purpose of this invention is to overcome the shortcomings of the prior art.

[0028] The object of this invention is particularly to provide a container with good mechanical properties and good blowability.

[0029] Another object of the present invention is to provide a container with good stability, whether filled or empty.

[0030] The object of this invention is to provide a container with an improved aesthetic appearance compared to the prior art.

[0031] These objectives, as well as other objectives to be shown below, are achieved by means of a container intended for use with plastic materials, the container comprising a body extending along a longitudinal axis between an opening and a bottom, the bottom having:

[0032] - A base that forms the surface on which the container is placed;

[0033] - A recessed vault that revolves around the longitudinal axis and extends from near the base to the amorphous central region;

[0034] -A reinforcing protrusion that rises from the recessed vault and extends radially within the vault.

[0035] Its characteristic is that by alternating between a first protrusion and a second protrusion distributed along the following portion, the protrusions are reinforced to be spaced apart at an angle from each other:

[0036] - A first annular strip, in which a first protrusion extends from a first end adjacent to the base to a second end, the first protrusion causing the second annular strip to be located between its second end and the amorphous central region;

[0037] - A third annular strip, in which a second protrusion extends from a first end adjacent to the amorphous center region to a second end, the second protrusion causing a fourth annular strip to be located between its second end and the base.

[0038] The alternating stripes of raised sections effectively reinforce the base while creating a pleasing visual pattern.

[0039] The alternating distribution of the first and second protrusions in two strips provides a good distribution of stress exerted on the dome by the contents of the container, especially when the contents are carbonated beverages.

[0040] Furthermore, the alternation of the first and second protrusions ensures good quality of the base without reducing the mechanical resistance of the dome, which guarantees good stability of the container, whether it is filled or not.

[0041] Advantageously, the bottom has a fifth annular strip located between the second end of the first protrusion and the second end of the second protrusion, with the first and second protrusions partially extending in the fifth annular strip.

[0042] The fifth annular band has high mechanical resistance at the bottom so that the vault is resistant in the part where the stress is greatest.

[0043] According to another feature, the vault comprises two distinct regions, namely a first region and a second region separated by a staircase; and the second end of the first protrusion extends into the second region at a distance from the staircase between 25% and 65% of the total unfolded length of the second region, and the second end of the second protrusion extends into the first region at a distance from the staircase between 25% and 65% of the total unfolded length of the first region.

[0044] Therefore, in the fifth annular strip, there is an annular covering portion of the first protrusion and the second protrusion.

[0045] Advantageously, the staircase has a step diameter The base has a base diameter ratio It is between 0.5 and 0.85.

[0046] The presence and size of the steps ensure that, under overpressure conditions within the container, only the upper part of the dome, i.e., between the steps and the amorphous central region, cannot be reversed, thus preventing the base from deforming and maintaining the container's stability.

[0047] In this case, the height H of the steps P and the height H of the vault extension V The ratio of H P / H V It is between 0.4 and 0.8.

[0048] In other words, in the cross-section taken from the fifth annular strip, it should be noted that between the two successive first protrusions is a second protrusion, which creates a roughly star-shaped profile as in the prior art. This ensures good mechanical strength, while this profile poses no risk to the stability of the container.

[0049] According to a preferred embodiment, the base has a base diameter (also known as the diameter of the base) ) and the height H of the vault extension V ratio It is between 0.2 and 0.4.

[0050] This ensures good mechanical strength of the vault, eliminating the risk of collapse. Furthermore, the container's blowability remains unaffected.

[0051] Therefore, in the case of the upper part of the dome being reversed, the amorphous central region cannot extend beyond the placement plane formed by the base, thus maintaining the stability of the container.

[0052] According to an advantageous implementation method:

[0053] - The vault is connected to the base via an inner circular segment with a radius between 0.5mm and 3mm, and

[0054] - The base is joined to the rounded corner of the container body by an outer circular segment with a radius between 1 mm and 5 mm, which joins the bottom of the container to the container body.

[0055] These dimensions allow for the avoidance of stretching at the bottom and sagging at the vault.

[0056] In other words, these values ​​allow for restrictions on the development of the inner and outer circular segments, meaning they tend to be linear, which ensures that the vault maintains the shape that allows it to resist pressure within the container.

[0057] Advantageously, the first protrusion and the second protrusion extend along separate arcs between their respective first ends and their respective second ends, each arc having a radius of curvature equal to the diameter of the base. Between 25% and 45%.

[0058] The curvature radii of the first and second protrusions are selected to ensure that they do not affect the blownability of the container, while ensuring good mechanical strength at the bottom.

[0059] Preferably, the container has a bottom comprising at least five first protrusions and five second protrusions.

[0060] The number of protrusions also allows for good rigidity of the bottom of the container without affecting its blowability.

[0061] The present invention also aims to provide a model for manufacturing a container from a preform made of plastic material, the model comprising two mutually movable walls for forming the body of the container and a model bottom movable relative to the walls, the model bottom being used to form the bottom of the container by pushing the constituent plastic material of the container toward its opening, characterized in that the model bottom comprises:

[0062] - A first annular portion, used to at least partially form a base;

[0063] - The second part of the dome shape is used to contact the amorphous central region of the preform to form an arch.

[0064] Part Two Carrying:

[0065] - A raised first annular strip, used to form a first protrusion adjacent to the base.

[0066] - A raised second annular strip is used to form a second protrusion adjacent to the amorphous center region. Attached Figure Description

[0067] Other features and advantages of the invention will become more apparent from the following description of preferred embodiments of the invention, given by way of exemplary and non-limiting examples, with reference to the accompanying drawings:

[0068] - Figure 1 It is a bottom view of the container based on existing technology;

[0069] - Figure 2 This is a front view of the container according to the present invention;

[0070] - Figure 3 This is a bottom view of the container bottom according to the present invention;

[0071] - Figure 4 This is a detailed view of the bottom of the container according to the present invention;

[0072] - Figure 5 It is along Figure 3 A cross-sectional view of the bottom of the container according to the invention, showing the axis VV;

[0073] - Figure 6 This is a longitudinal sectional view of a manufacturing model of the container according to the present invention. Detailed Implementation

[0074] like Figure 2As shown, the container 10 according to the invention includes a body 11 that extends along a longitudinal axis X between an opening 121 and a bottom 13. The opening 121 is typically located at the end of a neck 122 situated above a shoulder 12 on the body 11.

[0075] More specifically, in the illustrated embodiment, container 10 is a bottle made of a thermoplastic material such as PET (polyethylene terephthalate).

[0076] exist Figure 3-5 The bottom 13 shown includes:

[0077] -Base 14,

[0078] - The recessed vault 15 and,

[0079] - Reinforcing protrusions 16 and 17, which protrude from the recessed vault 15 and extend radially into the vault 15.

[0080] The base 14 forms a placement plane 141 for the container 10. The placement plane 141 is generally in the shape of a ring on which the container 10 is placed.

[0081] The base 14 has a diameter defined according to the type and quantity of contents received in the container 10. (also known as the "diameter" of base 14) Therefore, for a large-capacity container 10, the diameter of the base 14 is... The diameter is larger than that of the smaller capacity container 10. More precisely, the capacity is defined by the amount of material (e.g., liquid) that the container 10 can contain.

[0082] In the following description, and in a conventional manner, all heights are measured from the placement plane 141 of the container 10, which serves as a reference plane.

[0083] The dome 15 rotates around the longitudinal axis X and extends from near the base 14 to the amorphous central region 151.

[0084] More precisely, the dome 15 is connected to the base 14 via an inner circular segment 18. The inner circular segment 18 has a radius between 0.5 mm and 3 mm. Preferably, the inner circular segment 18 has a radius of 1.5 mm.

[0085] In addition, the inner circular segment 18 has a concave shape, that is, the inner circular segment forms a cavity facing the interior of the base 14.

[0086] Between the inner circular segment 18 and the amorphous central region 151 of the dome 15, the dome includes two distinct regions 15A and 15B forming a step 24 between them. The first region 15A is located between the inner circular segment 18 and the second region 15B, which extends to the amorphous central region 151. The first region 15A is defined by an arc and has a concave surface pointing inwards towards the interior of the dome (and thus towards the exterior of the container). Similarly, the second region 15B is also defined by an arc and has a convex surface pointing inwards towards the interior of the dome 15, such that the step 24 is defined by a change in curvature between the two regions. In other words, the step 24 constitutes the separating boundary between regions 15A and 15B. The diameter of the step 24... (also known as "step diameter") The diameter is defined as the diameter when there is a change in curvature. Therefore, the diameter of the step is determined at step 24.

[0087] diameter of the steps Advantageous selection of ratio Includes values ​​between 0.5 and 0.85.

[0088] Preferably, compared to It is 0.69.

[0089] Furthermore, step 24 is located at a height H measured from the placement plane 141 of container 10. P Location. Height H P Select the stepped height H P and the height of the vault H V The ratio between H P / H V Includes values ​​between 0.4 and 0.8.

[0090] To obtain good mechanical properties for the bottom 13 of container 10, compared to H P / H V The preferred value is 0.63.

[0091] As in Figure 5 As shown above, the vault 15 is therefore separated from the placement plane 141 by a separation height H between 0.2 mm and 2 mm. e Preferably, the separation height H e It is 0.75mm.

[0092] The amorphous central region 151 is centered on the longitudinal axis X and has a diameter The material disc is shaped as described above. The disc did not deform during the blowing process of container 10.

[0093] Therefore, the height H of the vault can be limited to 15. V It was measured between the placement plane 141 and the amorphous central region 151 of the dome 15.

[0094] To ensure the mechanical strength of the vault, the height H of the vault is 15. V Limited to proportional

[0095] Included between 0.2 and 0.4.

[0096] Preferably, the height H of the arch is determined. V Proportion It equals 0.29. Therefore, a suitable mechanical strength for the vault 15 will be obtained.

[0097] Still referencing Figure 3-5 It should be noted that the reinforcing protrusions 16 and 17 are spaced apart at an angle from each other by alternating the first protrusion 16 and the second protrusion 17.

[0098] The first protrusion 16 extends along an arc 163 between the first end 161 and the second end 162, the arc having a diameter including the base. The radius of curvature is between 25% and 45%.

[0099] The arc 163 of the first protrusion 16 is connected to the dome 15 by each of the first facet 164 and the second facet 165 extending from one side of the arc 163.

[0100] The facets 164 and 165 of the first protrusion 16 have a planar shape so that the first protrusion 16 forms a V in cross-section. However, the facets 164 and 165 may also have a raised shape.

[0101] The second protrusion 17 extends along an arc 173 between the first end 171 and the second end 172, the arc having a diameter including the base. The radius of curvature is between 25% and 45%.

[0102] The arc 173 of the second protrusion 17 is connected to the vault 15 via the first facet 174 and the second facet 175, each of the first and second facests extending from one side of the arc 173.

[0103] The facets 174 and 175 of the second protrusion 17 have a planar shape so that the second protrusion 17 forms a V in cross-section. However, the facets 174 and 175 may also have a raised shape.

[0104] Preferably, the bottom 13 of the container 10 includes at least five first protrusions 16 and five second protrusions 17.

[0105] according to Figure 3-5 In the embodiment shown, the bottom 13 includes seven first protrusions 16 and seven second protrusions 17.

[0106] In any case, the number of the first protrusion 16 and the number of the second protrusion must be the same.

[0107] Protrusions 16 and 17 are distributed in multiple annular strips, as shown in... Figure 3-5 As shown in the image.

[0108] A first annular strip 19 is defined, in which a first protrusion 16 extends from its first end 161 near the base 14 to its second end 162. The first annular strip is located in the second region 15B of the dome 15, above the step 24, and between the step and the amorphous center region 151.

[0109] The first protrusion 16 thus defines a second annular strip 20 between its second end 162 and the amorphous central region 151.

[0110] A third annular strip 21 is defined, wherein the second protrusion 17 extends from its first end 171 near the amorphous center region 151 to its second end 172 in the second region 15B of the vault 15, and the third annular strip is located in the first region 15A of the vault 15, between the step 24 and the base 14.

[0111] The second protrusion 17 defines the fourth annular strip 22 between its second end 172 and the base 14.

[0112] The fifth annular strip 23 is limited by the second end 162 of the first protrusion 16 and the second end 172 of the second protrusion 17. Therefore, each of the first protrusion 16 and the second protrusion 17 extends partially within the fifth annular strip 23.

[0113] More specifically, the protrusion 16 extends from its second end 162 into the second region 15B of the vault 15, separated from the step 24 by a distance between 25% and 65% of the total unfolded length of the region 15B.

[0114] The “total unfolded length” of region 15B refers to the measured length of the arc that defines region 15B.

[0115] As for the protrusion 17, it extends through its second end 172 into the first region 15A of the vault 15, separated from the step 24 by a distance between 25% and 65% of the total unfolded length of the region 15A.

[0116] The “total unfolded length” of region 15A refers to the length of the arc that defines region 15A.

[0117] As in Figure 3 and 4As shown above, the first protrusion 16 and the second protrusion 17 are spaced apart from each other.

[0118] More precisely, the first protrusion 16 and the second protrusion 17 are separated by a distance of less than or equal to 4 mm, and preferably by a distance of about 1 mm.

[0119] However, in order to increase the mechanical strength of the bottom, the adjacent first protrusion 16 and second protrusion 17 can be designed to contact each other, that is, the distance between them is zero.

[0120] As in Figure 3-5 As shown above, the bottom 13 includes a joining fillet 131, through which the bottom 13 is joined to the body 11 of the container 10.

[0121] For more accurate information, please refer to Figure 5 The base 14 is joined to the engagement fillet 131 via an outer circular segment 25. The outer circular segment 25 has a radius between 1 mm and 5 mm. Preferably, the outer circular segment 25 has a radius of 3 mm.

[0122] In addition, the outer circular segment 25 has a protruding shape, that is, it forms a cavity facing the interior of the container 10.

[0123] To manufacture container 10, and more specifically the bottom 13 just described, it is typically used as follows: Figure 6 Model 26 is shown.

[0124] This model 26 includes:

[0125] -The two sidewalls 27 for forming the body 11 and shoulder 12 of container 10, and

[0126] - Model bottom 28 used to form the bottom 13 of container 10.

[0127] The two sidewalls 27 are movable so that they can be separated or brought closer together, for example, like an opening in a wallet, to allow the blank (preform) of the container to be introduced and then the formed container 10 to be removed.

[0128] Advantageously, the bottom 28 of the mold is movable relative to the sidewall 27 to allow the container to be demolded and to allow the above-defined die-casting technique to be implemented, i.e. to form the bottom 13 of the container 10 by pushing its constituent plastic material toward its opening 121.

[0129] The bottom 28 of the model includes:

[0130] - For at least partially forming the first annular portion 281 of the base 14, and

[0131] - A second part 282 used to contact the amorphous central region of the preform to form the dome shape of the vault 15.

[0132] like Figure 6 As shown above, the second part carries:

[0133] - A first protrusion 16 is used to form a first annular strip 283 adjacent to the base 14.

[0134] - The second protrusion 17 is used to form a second annular strip 284 adjacent to the amorphous central region 151.

[0135] The bottom 13, as just described, provides good mechanical strength for the stress on the carbonated beverage contained in the container 10, while also providing a beautiful visual appearance. In fact, when viewed from below, as... Figure 3 As shown above, the bottom 13 has a sunflower shape, and the first protrusion 16 and the second protrusion 17 thus form the petals of the sunflower.

[0136] Furthermore, due to the first protrusion 16 and the second protrusion 17, the risk of instability is limited or even eliminated.

[0137] In fact, the separation between the first protrusion 16 and the second protrusion 17 allows for proper material flow into the mold 26 on the one hand, and ensures on the other hand that the material will not exit its predetermined molding position once molding is performed.

[0138] Furthermore, since the dome 15 has a region 152 including the base 14, the first protrusion 16 and the second protrusion 17 interposed between the two successive first protrusions 16, good material flow and no shrinkage are also achieved, and the region 152 has a larger area than that existing in the prior art.

[0139] Therefore, the first protrusion 16 extends to the immediate adjacent to the base 14, which avoids deformation of the base 14 that could cause instability in the container 10.

Claims

1. A model bottom (28) for manufacturing a container from a preform made of plastic material, the container (10) having a body (11) extending along a longitudinal axis between an opening (121) and a container bottom (13), the container bottom (13) having: a base (14) forming a placement plane (141) of the container (10); a recessed dome (15) that rotates about a longitudinal axis (X) and extends from near the base (14) to an amorphous central region (151); reinforcing protrusions (16, 17) ), protruding from the recessed dome (15) and extending radially within the dome (15), the bottom (28) of the model is movable relative to the wall (27) of the model (26), the walls of the model moving one relative to the other to form the body (11) of the container (10), the bottom (28) of the model is movable relative to the wall (27) to form the bottom (13) of the container (10) by pushing the constituent plastic material of the container (10) toward the opening (121) of the container, characterized in that, The bottom of the model (28) includes: - The first annular portion (281) is used to at least partially form the base (14). - A dome-shaped second portion (282) is used to contact the amorphous central region of the preform to form an arch (15), such that the reinforcing protrusions (16, 17) are spaced apart at an angle from each other by alternating the first protrusion (16) and the second protrusion (17) distributed along the first annular strip (19) and the third annular strip (21), in the first annular strip the first protrusion (16) extends from the first end (161) adjacent to the base (14) to the second end (162), the first protrusion (16) places the second annular strip (20) between the second end (162) of the first protrusion and the amorphous central region (151), in the third annular strip the second protrusion (17) extends from the first end (171) adjacent to the amorphous central region (151) to the second end (172), the second protrusion (17) places the fourth annular strip (22) between the second end (172) of the second protrusion and the base (14); Part Two (282) Bearing: - A first annular strip (283) for forming a protrusion (16) adjacent to the base (14). - A second annular strip (284) for forming a second protrusion (17) adjacent to the amorphous central region (151). The bottom of the model (28) is shaped such that the vault (15) comprises two distinct regions, namely a first region (15A) and a second region (15B) separated by a step (24); and the second end (162) of the first protrusion (16) extends into the second region (15B) at a distance from the step (24) between 25% and 65% of the total unfolded length of the second region (15B), and the second end (172) of the second protrusion (17) extends into the first region (15A) at a distance from the step (24) between 25% and 65% of the total unfolded length of the first region (15A).

2. The model bottom (28) according to claim 1, characterized in that, The bottom of the model is shaped such that the bottom of the container (13) has a fifth annular strip (23) located between the second end (162) of the first protrusion (16) and the second end (172) of the second protrusion (17), the first protrusion (16) and the second protrusion (17) extending partially in the fifth annular strip.

3. The model bottom (28) according to claim 1 or 2, characterized in that, The bottom of the model is shaped such that the step (24) has a step diameter (Ø). P The base (14) has a base diameter (Ø A ), so that the ratio of the step diameter to the base diameter (Ø P / Ø A The value is between 0.5 and 0.

85.

4. The model bottom (28) according to claim 1 or 2, characterized in that, The bottom of the model is shaped such that the steps (24) have a height (H) P The vault (15) extends to a height (H) V On the other hand, this makes the ratio of the height of the steps to the height of the vault extension (H) P / H V The value is between 0.4 and 0.

8.

5. The model bottom (28) according to claim 1 or 2, characterized in that, The bottom of the model is shaped such that the base (14) has a base diameter (Ø). A The vault (15) extends to a height (H) V ), so that the ratio of the base diameter to the height of the vault extension (Ø A / H V The value is between 0.2 and 0.

4.

6. The model bottom (28) according to claim 1 or 2, characterized in that, The bottom of the model is shaped such that: - The vault (15) is connected to the base via an inner circular segment (18) with a radius between 0.5 mm and 3 mm, and - The base (14) is joined to the joint fillet (131) by an outer circular segment (25) with a radius between 1 mm and 5 mm, which joins the bottom (13) of the container (10) to the body (11) of the container (10).

7. The model bottom (28) according to claim 3, characterized in that, The bottom of the model is shaped such that the first protrusion (16) and the second protrusion (17) of the concave dome (15) extend along respective arcs (163; 173) between their respective first ends (161; 171) and their respective second ends (162; 172), each arc (163; 173) having a radius of curvature equal to the diameter (Ø) of the base (14). A Between 25% and 45%.

8. The model bottom (28) according to claim 1 or 2, characterized in that, The bottom of the model is shaped such that the concave dome (15) includes at least five first protrusions (16) and five second protrusions (17).

Images