Plastic container with heat-resistant base

Abstract

A plastic container (1), in particular for beverages, with an opening (12) through which a liquid can be withdrawn from the container, comprising a base body (14) extending in a longitudinal direction (L) to this opening (12) and a bottom section (2) extending in this longitudinal direction (L) to this base body (14), wherein the bottom section (2) has at least three support feet (4), wherein outer surfaces (4a) of these support feet (4) each form a segmentally ring-shaped support section (20a, 20b, 20c) of the plastic container (1) extending over a predetermined circumferential angle (a1, a2, a3..) and wherein at least three grooves (6) are formed between these support feet, wherein these grooves (6) extend at least also in a radial direction (R) of the plastic container perpendicular to the longitudinal direction (L),wherein these grooves (6) each have a groove base (62) extending at least also in the radial direction (R) and a wall section (64) extending from this groove base (62) at least also to a support section (20a, 20b, 20c) of a support foot adjacent to this groove base (62), wherein the container is formed in one piece and the bottom section (2) has a injection point (18) located inside in a radial direction (R) with respect to the longitudinal direction (L) and the bottom section (2) preferably has a central area (7) surrounding this injection point (18) and a transition section extending from this central area (7) to the base body (14), wherein a geometric bottom line (BL) formed along the bottom section (2),which in a projection along the longitudinal direction (L) forms a circle around the injection point (18) and extends from a base section (20a) fully to this base section (20a) over at least one groove base (62), has a larger radius of curvature in the area of ​​the groove base (62) than in the two laterally adjacent sections (BLa, BLb) of the base line, characterized in that the wall of the container is convex outwards in the area of ​​the groove base (62) and in the area of ​​a geometric center of the groove base (62).

Description

[0001] The present invention relates to a plastic container, and in particular a beverage container. A virtually unmanageable variety of different plastic containers are known from the prior art. These exist with different filling capacities, for example, 0.5 liters, 1 liter, or even up to 5 liters. These plastic containers must meet a wide range of requirements. In particular, container bases, hereinafter referred to as petaloid bases, are known from the prior art. These bases form a plurality of feet on which the container stands. These bases are used especially for filling carbonated beverages. While these bases offer the advantage of high stability, they are not suitable for high ambient temperatures, such as those found in subtropical countries.

[0002] The present invention is therefore based on the objective of providing a container that is particularly suitable for use at high ambient temperatures, such as those occurring in subtropical countries. This objective is achieved according to the invention by a container according to claim 1. The invention is also achieved by a mold for producing a container according to claim 1. It should be noted that such molds, in particular blow molds, are used to produce such containers. As is known in the prior art, the container is expanded by applying blowing pressure against an inner wall of this blow mold. Therefore, in order for a blow mold to be suitable for producing a specific container, the contour of its inner wall must have the same shape as the container to be produced or represent a negative of this contour.

[0003] A plastic container according to the invention, particularly for beverages, has an opening through which a liquid can be dispensed from the container. Furthermore, this plastic container has a base body extending longitudinally from this opening and a bottom section extending longitudinally from this base body. This bottom section has at least three feet, the outer surfaces of which each form a segmentally ring-shaped base extending over a predetermined circumferential angle. At least three grooves are formed between these at least three feet, these grooves extending at least also in a radial direction perpendicular to the longitudinal direction of the plastic container.

[0004] In addition, the grooves have a wall section that extends from the base of these grooves at least to a support section of a base adjacent to this groove base. Furthermore, the container is formed in one piece, and the bottom section has a injection point located radially inside the longitudinal direction. The bottom section preferably has a central area surrounding this injection point and a transition section extending from this central area to the base body. It should be noted that the injection point itself can also constitute this central area.

[0005] According to the invention, a geometric base line formed along the base section, which in a projection along the longitudinal direction forms a circle around a injection point or a geometric center of the base section and extends from a support section fully to this support section across at least one groove base, has (when projected in a direction perpendicular to the longitudinal direction of the container) a larger radius of curvature in the region of the groove base than in the two sections of the base line located laterally adjacent to this groove base. The curvature preferably results from a projection of this circle in a radial direction of the base section or, as mentioned, in a direction that would be perpendicular to the longitudinal direction of the container (and in which projection a circle would appear as a straight line).

[0006] To describe the base section, a geometric circular line is considered, which is formed around the geometric center of the base section and thus extends over all feet and groove bases. In contrast to devices or containers from the prior art, this line does not exhibit a strong curvature in the area of ​​the groove base, but rather a very slight curvature in this area, preferably an at least approximately straight course, and preferably a straight course (in the aforementioned circumferential direction). In other words, this straight course is present when the base line is projected in a radial direction of the container. With respect to the base line, this means that this base line extends as a circle in exactly one plane. The straightness, or rather,The curvature of this ground line is therefore preferably understood in relation to a circular line as being straight with respect to a line perpendicular to the plane of the circle.

[0007] This groove base is also referred to as a tension band. It provides stiffening in the base area, thus offering a base design suitable for both lightly and highly pressurized products. The internal pressure can range from 0 g / l to 10 g / l CO2.

[0008] For PET containers with a capacity between 200 ml and 5 liters, it is proposed to provide a container that can be manufactured with a low final blow molding pressure, thus requiring less energy, and that also features improved formability of the base geometry and enhanced thermal stability up to 50°C for 50 hours. Such containers are particularly advantageous for climate zones such as the Middle East, Pakistan, India, Mexico, and Asia. The base can be a freeform design. The improved thermal stability is achieved primarily through modifications to the tension band and / or the groove base.

[0009] As mentioned above, the aforementioned ground line is circular in projection perpendicular to the longitudinal direction, and when it is projected or rolled out again perpendicular to the longitudinal axis, it exhibits a multitude of maxima and minima and an overall wave-like structure.

[0010] It is therefore proposed that the groove base be less curved than the surrounding areas. This less curved and preferably also wider groove base thus provides a broader tensile band and therefore greater stability. This geometric base line extends across all groove bases and thus also across all feet. The groove base, in turn, forms a local minimum of the base line when viewed from below. With reference to the upright container, the groove base is the area that projects furthest towards the interior volume of the container.

[0011] In a further advantageous embodiment, the wall of the container is convex in the region of the groove base, and particularly in the region of the geometric center of the groove base. In the prior art, said groove base is the region that is most convex inwards. Within the scope of the present invention, it is proposed that this region, which contains the geometric center of the groove base, is again convex outwards, although naturally much less so than the feet themselves. Thus, this groove base will never touch the ground, but the outward curvature increases stability. The term "outward" is used here with reference to the internal volume, i.e., in the sense of "away from any liquid contained in the container."

[0012] In a further advantageous embodiment, the width of the groove base widens outwards in a radial direction of the container. This widens, in particular, the area of ​​the groove base that has a slight curvature, or the area that is convex outwards relative to the container. In other words, the groove base widens from the inside out in its circumferential direction. Advantageously, this groove base widens continuously, so that this width can also be described by an opening angle of the groove base. In other words, the groove base can be defined by two straight lines that bound it. These lines intersect and, preferably at a distance from the injection point, form an angle, and in particular an acute angle.The lines in question can intersect at a circular line that is geometrically formed around the geometric center of the container and preferably also lies outside the injection point.

[0013] In a further advantageous embodiment, the base line has a plurality of local maximum regions, each located in a region of the respective support feet along the circumference of the container. For a given radius of the base line, these maximum regions also define the aforementioned contact surfaces. Advantageously, the base line has as many maximum regions as there are support feet. Advantageously, the base line also has as many minima or groove bases as there are support feet.

[0014] Preferably, the bottom line in these maximum regions has a larger radius of curvature than in the two regions laterally adjacent to these maximum regions. These two adjacent regions are, in particular, the wall sections that lead from the maximum regions to the respective groove bases. These maximum regions also advantageously define the sections that extend furthest downwards when the container is upright.

[0015] In a further advantageous embodiment, the width of this maximum area also increases in a radial direction outwards of the container. Here, the width is defined in a circumferential direction, for example, along the base line.

[0016] In a further advantageous embodiment, the width of at least one maximum area is greater than the width of a groove base. Advantageously, the widths of all maximum areas are greater than the widths of the respective groove bases. Advantageously, the widths of the groove bases are each the same, and advantageously, the widths of the maximum areas are also each the same.

[0017] Advantageously, at least one groove base has a circumferential angle that is between 0° and 20°, preferably between 0.5° and 12.5° and particularly preferably between 0.5° and 8°.

[0018] In a further advantageous embodiment, at least one maximum region has a circumferential angle that lies between 1° and 30°, preferably between 2° and 20°.

[0019] Advantageously, the ratio between the angle of a maximum area and the groove base is between 1.5:1 and 3:1, and preferably between 1.5:1 and 2.5:1.

[0020] In a further advantageous embodiment, the bottom line has at least three inflection points, and preferably at least four, between two adjacent maxima. This number of four inflection points results in particular from the curvature of the groove base. The inflection points can, in turn, be determined by a rolled-up or projected view of the bottom line.

[0021] The present invention is further directed to a blow molding device for the production of plastic containers, which has an inner wall against which a plastic container can be expanded during a blow molding process.

[0022] According to the invention, the inner wall has a contour which is suitable and intended to produce a plastic container at least according to one of the preceding claims.

[0023] In particular, the blow molding device has a bottom part which is suitable and intended to produce a bottom section of the type described above.

[0024] In another advantageous embodiment, the ring-segment-shaped support sections define a support plane for the container, which is perpendicular to the longitudinal direction of the container.

[0025] In a further advantageous embodiment, the container has between three and twelve feet, preferably between four and eight feet, and particularly preferably between four and seven feet. The number of these feet also has an advantageous effect on the circumferential width of the groove base or on the circumferential width of the maximum areas.

[0026] In a further advantageous embodiment, the ratio between the outer diameter of the plastic container and the base circle diameter is between 0.5 and 0.99, preferably between 0.5 and 0.9 and particularly preferably between 0.6 and 0.8.

[0027] Advantageously, the soil section exhibits at least a first dome-like structure extending towards a center of the soil section, at least in sections. However, it would also be conceivable that this area extending towards the center of the soil section is straight or flat.

[0028] In a further advantageous embodiment, the center of the base section is positioned lower in the longitudinal direction of the plastic container than another section of the base section. In other words, the geometric center, and in particular the injection point, projects further upwards than other areas when the container is upright. This prevents the injection point from touching a surface, even at higher internal pressures within the container, and thus prevents the container from compromising its stability.

[0029] In a further advantageous embodiment, the bottom section has a injection point in its center and at least one groove base extends to this injection point or is less than 5 mm away from this injection point.

[0030] Advantageously, the transition section mentioned above between the central area and the base body of the container has a curvature with a finite radius of curvature in at least one direction perpendicular to the longitudinal direction in each subsection.

[0031] Furthermore, an outer surface of the transition section is preferably formed as a first curve in a projection in at least one, and preferably in every, direction perpendicular to the longitudinal direction. This first curve has exactly two points where the second mathematical derivative of a mathematical function representing this first curve has the value 0. More precisely, the curvature of the respective curve changes sign at these points. In a further advantageous embodiment, these two points are symmetrically opposite each other with respect to a longitudinal axis of the container. This applies particularly to containers with an even number of feet. However, when considering these points, the central region is excluded, which can also be straight (meaning the second derivative can also be permanently 0).Preferably, a region of the first curve, which lies between one of these points and the central region, exhibits a continuously changing curvature.

[0032] In a further advantageous embodiment, the outer surface of the transition section is projected in at least one direction perpendicular to the longitudinal direction as a second curve, wherein the second mathematical derivative of a mathematical function representing this second curve does not have the value 0 in any section of the second curve. In other words, this second curve has no inflection point, and the aforementioned curve has two inflection points.

[0033] Advantageously, the bottom section is designed to be point-symmetrical with respect to the injection point. In a further advantageous embodiment, the central area has a radius of less than 10 mm, and preferably less than 5 mm, with respect to the geometric center point. In yet another advantageous embodiment, the transition section adjoins the central area directly.

[0034] In a further advantageous embodiment, the transition section has a first curvature region with a substantially constant radius of curvature. Advantageously, a second curvature region adjoins the first curvature region radially outwards, this second curvature region also preferably having a constant second radius of curvature.

[0035] Advantageously, the first and second curvature regions are curved in the same direction. In a further advantageous embodiment, the radius of curvature of the second curvature region is larger than the radius of curvature of the first curvature region. In a further advantageous embodiment, the bottom section is a free-form bottom section. Furthermore, the plastic container advantageously has a capacity of at least 250 ml.

[0036] Further advantages and embodiments are shown in the accompanying drawings. These show: Fig. 1 A state-of-the-art plastic container; Fig. 2 a representation of a course in the area of ​​a base of a container according to the invention; Fig. 3 a representation of a curvature profile in which in Fig. 2 shown section; Fig. 4 a representation of a course in a groove base or tension band; Fig. 5a, Fig. 5b two representations of bottom sections of containers according to the invention; Fig. 6. A representation to illustrate angular ranges; Fig. 7 a perspective drawing to illustrate the groove base and the standing area; Fig. 8 an enlarged representation in the area of ​​a base; Fig. 9 another representation of a section of ground; Fig. 10 a representation of a floor line; Fig. 11 a representation of a bottom line in the area of ​​a groove bottom; Fig. 12 another representation of a ground area with an illustration of radii of curvature; Fig. 13 another representation of a section of ground; Fig. 14 another representation of a top view of a section of ground; Fig. 15 a representation of a section of ground with a ground line; Fig. 16 the floor line from Fig. 15 excluding the bottom section; and Fig. 17 a projection of the bottom line in a direction perpendicular to the longitudinal direction of the container.

[0037] Fig. Figure 1 shows a representation of a container 1 according to the applicant's internal prior art. This plastic container 1 has an opening 12 and a base body 14 adjoining this opening. The base body 14 serves to hold the main filling volume. The shape of the base body can also differ from that shown. Fig. Figure 1 shows the container and can, for example, have grooves or patterns. Reference numeral 22 denotes an external thread of the container 1, and reference numeral 24 denotes a support ring located at the opening. The container according to the invention also preferably has an external thread and a support ring. Reference numeral 4 denotes a base of the container, and reference numeral 4a denotes an outer surface of this base.

[0038] The reference symbol L refers to a longitudinal direction of the plastic container. A base section is attached to this base body 14, with the base body 14 transitioning into this base section 2 via a curved section. It can be seen that the base has several feet that allow it to stand upright on a flat surface. The reference symbol R refers to a radial direction of the container base.

[0039] Fig. Figure 2 shows a representation of the ground section in the area of ​​such a base. More precisely, the illustration in Fig. The line shown in Figure 2 traces the course in the area of ​​the base. The base contour in this area is initially described by a straight line 101, followed by a spline or curved section 102. This curved section 102 is followed by another curved section or spline 103, and then by another curved section 104, with which the base section transitions into the main body 14. From this in Fig. The contour shown in Figure 2 can be used to create the foot surface, as explained in more detail below, by rotating the floor geometry around the axis of rotation M (which also defines the geometric center of the floor section).

[0040] The transitions from the straight section 101 to the curved section 102 at point F and / or the transition from the curved section 102 to the base radius 103 at the illustrated point E are preferably tangent-continuous. The position of point E can be controlled via the angle 110 on the base radius of section 103. Preferably, the transition to the curved section or spline 104 is also tangent-continuous, and more preferably curvature-continuous. The curved section 104 preferably transitions tangent-continuously, and more preferably curvature-continuously, into the base body or the outer diameter of the container.

[0041] The curvature profile of this curved section 104 can be described by a polynomial of degree n.

[0042] The outer dimensions of the base section are determined by the outer diameter or radius 105 and the base height 106. The diameter or radius of the base circle 107 is preferably defined by a ratio to the outer diameter 105. The height of the straight line 108 is preferably described by a ratio to the outer diameter 105.

[0043] The starting point D of the curved section 104 is generated here by a straight line between point B and point C. This line BC is advantageously arranged tangentially to the base radius. The starting point D of the curved section 103 can in turn be determined using the angle 109 on the base radius of section 103 between points A and C.

[0044] Fig. Figure 3 shows a progression of the curvature of the in Fig. In section 2, it can be seen that section 102 is curved in a first direction and section 103 in a second direction. Between these two sections is an inflection point W where the curvature changes. It is also evident that the curvature in section 103 is greater than in section 104. The respective lines extending perpendicular to the curve provide a measure of the inverse curvature; that is, the longer the respective lines, the larger the radius of curvature and the smaller the curvature. Therefore, the entire profile of the soil segment resulting from sections 102, 103, and 104 has only one inflection point.

[0045] Fig. Figure 4 shows a profile in the area of ​​a groove base 62 or tension band. In this area, the contour is initially described by a straight line 114 and the subsequent large tension band radius 111, a region that preferably has a constant curvature. A region 112 with a smaller tension band radius adjoins this region 111. A section 113, in which the profile can also be straight, adjoins this region 113. The base contour of the foot and the transition to the base body adjoin this region 113. The tension band surface is also generated from this contour, as shown in more detail below, by a rotation about the axis of rotation M. Here, too, the transitions between region 111, region 112, section 113, and the base contour 104 are advantageously tangent-continuous.

[0046] The Fig. 5a and Fig. Figure 5b shows two floor sections. These differ in the number of feet. For better illustration, Fig. 5a is shown in grayscale, as this makes the transition areas between the feet more visible. The in Fig. The floor section shown in 5a has five support feet, which is in Fig. Figure 5b shows eight feet on the base. Reference numerals 20a, 20b, 20c, 20d, and 20e identify the support sections that allow the container to stand on a surface. Reference numeral R indicates a radial direction. Each support section extends by a circumferential angle a1, a2, etc. Grooves 6 are formed between the feet, extending radially along the plastic container and base section 2. Reference numeral 62 indicates the base of each groove. Reference numeral 18 indicates a molding point on the container. Reference numeral 7 indicates a central area surrounding the molding point 7.

[0047] The reference symbol BL designates a geometric base line, which here is formed as a circular line around the injection point or the center of the container. This base line, which can have different radii, thus covers both the support feet and the respective groove bases. The reference symbol 64 designates a wall section that leads from the respective support foot or the surface to the adjacent groove base 62. The size of an opening angle of the respective support foot 4 results from the number of feet used (360° divided by the number).

[0048] The abbreviation FF denotes the base surface and the reference symbol ZF the respective tension band surface or groove base surface. Between these lie the freeform surfaces marked SB. These freeform surfaces thus also represent the transitions or wall sections 64.

[0049] Fig. Figure 6 shows a diagram illustrating the respective angles. The angle segment WS corresponds to the opening angle of the number of feet and results from the number of feet used. This angle segment corresponds here to the angle between two adjacent groove bases. The base contour of the foot is defined around the central axis M with a foot angle FW, which is preferably between 0° and 20° and particularly preferably between 0° and 10°. The [missing information] lies centrally in the angle segment WS shown. Fig. 5a and Fig. 5b shows the base surface FF. The base contour of the tension band or the groove base 62 is rotated at both ends of the angled segment. The angle of the groove base or the tension band angle ZW can be between 0° and 20°, and in particular between 0.5° and 12°.

[0050] Fig. Figure 7 shows another view to illustrate the invention. Here again, the tensile band surface ZF (or groove base surface) and the base surface FF, which also forms the base circle, can be seen. The freeform surfaces SB are located between these surfaces. Lines L1 and L2 are straight lines that define the tensile band surface. It can be seen that the width BR of this tensile band or groove base 62 increases from the inside out. Lines L3 and L4 define the base surface. These are also straight lines projected along the longitudinal direction L of the container, forming the base surface FF between them. The reference numeral BM refers to the width of a maximum area. This width BM also increases outwards in the radial direction R of the container.

[0051] Fig. Figure 8 shows a partial representation of the foot area of ​​a container. The freeform surfaces SB, formed between the foot surface FF and the tension band surface ZF, are again visible.

[0052] Fig. Figure 9 shows a further representation of a bottom section 2 according to the invention. Here, the injection point 18 is particularly visible, as well as a central area 7 surrounding this injection point, from which the respective lines or groove bases 62 and also the base surfaces FF extend. The respective central line ZL is located in the middle of the groove base 62.

[0053] Fig. Figure 10 shows a further illustration of the invention. In particular, the base line BL is also shown, which – as described above – extends around the injection point 18 in the form of a circle. It can be seen that this base line has a predetermined curvature and, viewed from a starting point A to a starting point B, initially has no curvature or runs in a straight line in the area of ​​the feet, then exhibits a changing curvature, and furthermore has two inflection points W where the derivative of a second derivative of a function describing this line vanishes or where an inflection point exists.

[0054] At this point, the direction of the curvature changes. In the area of ​​the groove base 62, the ground line BL is only slightly curved or even has a straight, i.e., uncurved, course. This is represented here by the gray bar in the area of ​​the groove base 62. However, in this area, the ground line can also be curved outwards, as explained above. In this case, the ground line between points A and B can also have four inflection points.

[0055] Fig. Figure 11 shows another representation of the baseline. Here again, the two inflection points W are visible, as well as the area of ​​the groove base 62, where the baseline BL (when projected in the radial direction) runs in a straight line. The baseline BL also shows no curvature in the areas of the support sections 20a and 20b (again when viewed in the radial direction). In other words, the baseline BL runs as a circle in a plane here.

[0056] It would also be possible to define a straight line which, when projected perpendicular to the longitudinal direction of the container, runs from one support leg to the next. This line would then be perpendicular to the longitudinal direction of the containers. Such a line would be essentially straight and preferably also horizontal in the area of ​​the groove base.

[0057] Fig. Figure 12 shows another view to illustrate the curvature profiles. Here, the two inflection points W are again clearly visible, as are the areas where the curvature of the base line BL is absent or where the radius of curvature is infinite.

[0058] Fig. Figure 13 shows another illustration of floor section 2. Here again, the injection point 18 is visible, as well as the respective groove bases 62 and the areas 20a, 20b, ... of the base surfaces. It can be seen that the individual groove bases do not extend directly to the injection point, but end in the central area 7 or at the edge of the central area 7.

[0059] Fig. 14 resembles the representation from Fig. 13, although not as in Fig. 13 five feet are provided, but eight feet. The circular line BL can be defined at different locations, i.e., with different radii. Preferably, however, this circular line BL always has the areas with very low curvature in the groove base, regardless of which section it is located in between the central area 6 and the outer radius of the container.

[0060] Fig. Figure 15 shows another representation of a soil section 2 with the soil line running around the center of soil section 2. It can be seen that this soil line runs across the individual support feet and groove bases.

[0061] Fig. 16 shows the floor line from Fig. 15, but without the bottom section. Here again, the groove base 62 is visible, which is only slightly or not at all curved. Adjoining this groove base 62 are the two laterally adjacent sections BLa and BLb, which are noticeably more curved than the groove base 62. The reference symbol MAX refers to the (local) maximum area, which also forms the base surface within a certain radius. This maximum area MAX also exhibits less curvature than the adjacent areas BLa and BLb that adjoin it. Preferably, this maximum area MAX is straight. Fig. 17 shows a projection of the in Fig. Figure 16 shows the bottom line in a radial direction, i.e., a direction perpendicular to the longitudinal direction. It can be seen that in this projection, both the groove base 62 and the maximum area MAX are straight lines. It can also be seen that the maximum area MAX is slightly longer than the groove base 62. Overall, the bottom line therefore has an approximately sinusoidal shape.

[0062] The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they are novel individually or in combination compared to the prior art. Reference symbol list A, B, C, D, E Point a1, a2, a3 inscribed angles BL geometric floor line BLa section of the floor line lying laterally next to the groove base 62 BLb section of the floor line lying laterally next to the groove base 62 FF Footbed FW Foot Angle L Longitudinal direction (of the plastic container) L1-L4 line M Rotation axis / central axis MAX local maximum range MAXa,b regions following the maximum region R radial direction (of the container bottom) SB Freeform Surfaces W turning point WS angle segment ZF tension band surface / groove base surface ZL Central Line ZW tension band angle 1 container 2. Ground section 4. Base (of the container) 4a Outer surface (of the base) 6 grooves / central area 7 Central Area 12 Mouth 14 basic shapes 18 Injection point 20a Stand section 20b Stand section 20c Stand section 20d Stand section 20th floor section 22 External threads (of the container) 24 Carrying ring (located at one mouth) 62 Grooved base / groove base 64 Wall section / foot surfaces / maximum area 101 Straight / straight section 102 Spline / curved section 103 Spline / curved section / base radius 104 Spline / curved section 105 outer diameter 106 Ground level 107 Base circle diameter 108 Even Area 111 Area 112 113 Section 114 Even

Claims

[1] Plastic container (1) in particular for beverages with an opening (12) through which a liquid can be withdrawn from the container, with a base body (14) extending in a longitudinal direction (L) to this opening (12) and a bottom section (2) extending in this longitudinal direction (L) to this base body (14), wherein the bottom section (2) has at least three support feet (4), wherein outer surfaces (4a) of these support feet (4) each form a segmentally ring-shaped support section (20a, 20b, 20c) of the plastic container (1) extending over a predetermined circumferential angle (a1, a2, a3..) and wherein at least three grooves (6) are formed between these support feet, wherein these grooves (6) extend at least also in a radial direction (R) of the plastic container perpendicular to the longitudinal direction (L),wherein these grooves (6) each have a groove base (62) extending at least also in the radial direction (R) and a wall section (64) extending from this groove base (62) at least also to a support section (20a, 20b, 20c) of a support foot adjacent to this groove base (62), wherein the container is formed in one piece and the bottom section (2) has a injection point (18) located inside in a radial direction (R) with respect to the longitudinal direction (L) and the bottom section (2) preferably has a central area (7) surrounding this injection point (18) and a transition section extending from this central area (7) to the base body (14), wherein a geometric bottom line (BL) formed along the bottom section (2),which in a projection along the longitudinal direction (L) forms a circle around the injection point (18) and extends from a support section (20a) fully to this support section (20a) over at least one groove base (62), has a larger radius of curvature in the area of ​​the groove base (62) than in the two laterally adjacent sections (BLa, BLb) of the base line. characterized by , that the wall of the container is convex in the area of ​​the groove base (62) and in the area of ​​a geometric center of the groove base (62). [2] Container according to claim 1, characterized by , that a width (BR) of the groove base (62) increases in a radial direction outwards of the container. [3] Container according to at least one of the preceding claims characterized by, that the base line (BL) has a multitude of local maximum areas (MAX) which are provided in the circumferential direction in a region of the respective feet. [4] Container according to claim 3, characterized by , that the floor line in these maximum areas (MAX) has a larger radius of curvature than in the two areas (MAXa, MAXb) that are laterally adjacent to these maximum areas (MAX). [5] Container according to at least one of the preceding claims characterized by , that a width (BM) of a maximum area (MAX) increases in a radial direction outwards of the container. [6] Container according to claim 4, characterized by , that the width (BM) of at least one maximum area (64) is greater than the width of a groove base (62). [7] Container according to at least one of the preceding claims characterized by, that at least one groove base has a circumferential angle that is between 0° and 20°, preferably between 0.5° and 12.5°. [8] Container according to at least one of the preceding claims characterized by , that at least one maximum range (MAX) has a circumferential angle that is between 1° and 30°, preferably between 2° and 20°. [9] Blow molding device for the production of plastic containers with an inner wall against which a plastic container can be expanded during a blow molding process, characterized by that the inner wall has a contour which is suitable and intended to produce a plastic container according to at least one of the preceding claims.

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