CN220563124U - Plastic container for containing liquid and mould thereof - Google Patents

Abstract

The utility model provides a plastic container for containing a liquid, the plastic container having a bottom with an at least partially encircling bottom surface, the plastic container having a base body connected to the bottom in a longitudinal direction, the base body forming an inner volume of the plastic container, in which inner volume liquid can be contained, and the plastic container having a mouth through which liquid can be filled into the plastic container, an arch structure being formed in the bottom which is curved in the direction of the inner volume, the arch structure having a central region, characterized in that the arch structure has a frustoconical portion and at least one circumferential stepped portion arranged outside the central region in the radial direction of the plastic container and/or the arch structure has at least two circumferential stepped portions.

Description

Plastic container for containing liquid and mould thereof

Technical Field

The present utility model relates to a plastic container, and in particular to a plastic container made of PET for containing liquids, in particular beverages.

Background

Many plastic containers are known in the art. They differ from each other in many ways, such as the geometry of the container bottom, the mouth geometry or the filling volume, etc. A particular difficulty faced by plastic containers is that they must be able to withstand high internal pressures, such as are the case for carbonated beverages. Moreover, the bottom of the plastic container often deforms due to high load and high internal pressure, which deteriorates the stability of the plastic container.

In this case, it is required that the plastic container can withstand a pressure, for example a pressure of up to 5 bar or up to 8.4 bar. In this case the plastic container is preferably capable of holding 200ml-5L of the filling.

Furthermore, the bottom geometry of the plastic container should be more efficiently shaped during manufacture.

Plastic containers known in the prior art have champagne bottoms with hemispherical depressions surrounded by a base ring. However, it is difficult to achieve a uniform material distribution in the base ring of the bottom part of a plastic container using such a base, because a uniform material distribution in the base ring cannot be achieved by a small offset of the plastic preform relative to the center of the base during bottle blowing. The uneven distribution of material in the base ring then again results in a somewhat greater deviation from the perpendicularity of the container.

Disclosure of Invention

The plastic container for holding liquids, in particular beverages, according to the utility model has a bottom with an at least partially encircling base. The bottom part is furthermore connected to a container base in the longitudinal direction, forming an interior volume of the plastic container, in which the liquid can be accommodated. Further, the plastic container has a mouth portion with a mouth through which liquid can be filled into the plastic container. In this case, the mouth preferably has a smaller cross section than the base.

Furthermore, in the bottom part, an arch-like structure or dome-like structure is formed which is curved in the direction of the inner volume, the arch-like structure having a central area.

In the present utility model, the arch structure has, at least in part, a frustoconical portion and at least one circumferential stepped portion disposed outside the central region in the radial direction of the plastic container.

In another aspect of the utility model, the arch has at least two stages of circumferential steps.

The two technical schemes provided by the utility model improve the stability of the plastic container by compensating the pressure difference at the same time. Preferably, the arch has a circumferential frustoconical portion and at least two stages of circumferential stepped portions. By the combination of these two solutions a stable bottom is obtained, which has the effect of compensating the pressure difference.

The partially encircling base is understood to be a base extending longitudinally around the plastic container. The base may be designed as a completely encircling or continuous base or the base may be interrupted by grooves as described in more detail below.

Preferably, the base is annular (without regard to the grooves or ridges).

Preferably, the frustoconical portion has a frustoconical termination terminating toward the central region. Preferably, the frustoconical portion is connected to the central region by a curved portion. Preferably, the central region is rotationally symmetrical. In a further preferred embodiment, the central region preferably has a circular cross section.

Preferably, the stepped portion has at least two opposing curved portions. Particularly preferably, the stepped portion has at least three curved portions which are arranged one after the other and have different curvatures, in particular, the three curved portions have opposite curvatures. Preferably, the three curved portions are connected by a straight line.

For convenience of description of the respective curved course of the cross-section of the container, a plane containing the longitudinal or central symmetry axis of the container is assumed.

In a further preferred embodiment, the stepped portion has at least four curved portions arranged in sequence, the four curved portions preferably having different curvatures, for example, a first curved portion having a positive curvature, a second curved portion having a negative curvature, a third curved portion in turn having a positive curvature and a fourth curved portion having a negative curvature.

The arch is preferably described in the following manner. The arch comprises, in order from inside to outside, a central zone which, in cross section, preferably forms a horizontal straight line, an arc or curved portion, another straight line (forming a cross section of the frustoconical portion), a stepped portion (having a plurality of curved portions and preferably straight portions between curved portions), and a root arc or curve of the standing portion; the arch is also connected to a spline (as explained in more detail below).

The stepped portions do not have to form steps in the horizontal direction, but the steps may be inclined at an angle to the horizontal direction. The connection between two such steps does not have to be in the vertical direction either, but the connection may also be at an oblique angle to the vertical direction.

In the profile shown in more detail below, the outer surface of the bottom geometry is produced by rotation about a longitudinal direction or about an axis of rotation. Preferably, the transitions between the radius, the straight line, the arc and the root arc are at least independent and preferably all tangentially continuous. As described in more detail below, the transition from the root arc to the spline curve is curvature continuous, more preferably, the transition is at least tangent continuous.

Preferably, the spline curve transitions into the outer diameter of the container.

In a further preferred embodiment, the circumferential stepped portion is formed between the circumferential conical or frustoconical portion and the bottom surface. The stepped portion serves to absorb deformation, for example, when the filling product generates an internal pressure.

In a further preferred embodiment, the bottom surface, the circumferential frustoconical portion and/or the stepped portion have a circular cross-section in one plane, preferably in several such planes, particularly preferably in all planes perpendicular to the longitudinal direction. In this case, the circular cross section is preferably designed rotationally symmetrical. Still further, the grooves or ridges may also extend in the circular cross-section, as described below.

In a further preferred embodiment, the central region has a circular shape. It is particularly preferred that the injection point of the container is provided in the central region (the injection point being derived from the formation process of the relevant plastic preform).

Particularly preferably, the central region extends horizontally in the radial direction of the container (with the container standing upright as the object of observation). Preferably, the central region is arranged rotationally symmetrical with respect to the longitudinal direction of the plastic container.

In a further preferred embodiment, at least two grooves and/or ridges extending in the radial direction of the plastic container are formed in the circumferential truncated cone and/or the bottom surface and/or the stepped portion.

The ridge preferably serves as a stiffening rib, in particular for stabilizing the bottom. Preferably, the plastic container has at least 3, preferably at least 4 and more preferably at least 5 of said grooves or ribs.

In another preferred embodiment, the plastic container has at most 12, preferably at most 10, preferably at most 8, more preferably at most 7 and most preferably at most 6 such ridges. Preferably, the ridges or stiffening ribs are substantially evenly distributed over the circumference of the bottom.

In another preferred embodiment, the ridge interrupts the bottom surface of the plastic container. The ridges are preferably designed as grooves or depressions, as seen from below. The recess preferably protrudes in the direction of the inner volume of the plastic container.

In a further preferred embodiment, the grooves and/or ridges extend into the frustoconical portion.

In a further preferred embodiment, the grooves and/or ridges in the radial direction have an outwardly increasing width.

Preferably, the radial ridges and/or ribs extend radially in a proportion in the radial direction of the conical portion towards the centre of the container. Preferably, said ridge and/or stiffening rib portions in the radial direction (or in the extension of the frustoconical portion) are at least 10%, preferably at least 15% of the total radial extent. In another preferred embodiment, the ridge and/or stiffening rib portions extend at most 80%, preferably at most 70%, more preferably at most 60% in the radial direction (and/or the direction of extension) of the frustoconical portion.

In a further preferred embodiment, the stepped portion enables a relative movement of the dome or dome-like structure with respect to the base body, in particular in the longitudinal direction of the container. The stepped portion may move the arch (and central region) as a whole. In this way, an elastic or relative movement of the frustoconical portion can be achieved by the stepped portion, thereby achieving an increase or decrease in the internal volume of the container within certain limits. In this way, a higher pressure or negative pressure in the container (as may occur, for example, when the hot beverage filled in the container cools) can be compensated.

In a further preferred embodiment, the material thickness of the plastic material of the stepped portion is different from the material thickness in the frustoconical portion and/or the base.

Thus, the material thickness of the plastic container in the stepped portion may be greater than its material thickness in the frustoconical portion and/or the base. The material thickness of the stepped portion in the plastic container is preferably at least 5% greater, preferably at least 10% greater, more preferably at least 15% greater and most preferably at least 20% greater than the material thickness in the base and/or the frustoconical portion.

The material thickness of the stepped portion in the plastic container is preferably at most 70% greater than the material thickness of the base and/or the frustoconical portion, preferably at most 60% greater, more preferably at most 50% greater and most preferably at most 40% greater.

In a further preferred embodiment, the stepped portion has at least two curved portions in opposite directions, which curved portions are connected to each other by a further or intermediate portion. The further portion particularly preferably extends in a straight line and/or has a radius of curvature which is at least 5 times, preferably at least 10 times, more preferably at least 20 times, most preferably at least 30 times the radius of curvature of the curved portion.

Preferably, at least one of the curved portions has a radius of curvature greater than 0.2 mm. Preferably, at least one of the curved portions has a radius of curvature of less than 3.0 mm.

In particular, the stepped portion is perpendicular to the longitudinal direction of the container, as seen in cross-section, or to a plane containing the longitudinal direction (and the recess is not provided in the stepped portion).

In a further preferred embodiment, a further intermediate portion follows immediately any one of the curved portions, and preferably a further curved portion follows immediately the further intermediate portion, in particular such that the curvature of the further curved portion extends opposite or opposite to the curvature of the curved portion preceding it.

It is particularly preferred that the further intermediate portion is also rectilinear or has a radius of curvature which is at least 5 times, preferably at least 10 times, more preferably at least 20 times the radius of curvature of the curved portion preceding it.

In another preferred embodiment, the stepped portion has four curved portions between which a straight portion or a substantially straight portion is provided, preferably two adjacent curved portions each being curved in opposite directions.

The above embodiment thus gives a stepped portion having at least two steps in total.

In a further preferred embodiment, the bottom surface meets (in particular directly) the curvature of the stepped portion. In a further preferred embodiment, the base surface is transitioned into the base body by a connecting portion, wherein the connecting portion is particularly preferably designed as a spline curve, and the curvature profile of the spline curve is particularly preferably represented by an n-degree polynomial, the degree of which is preferably between 2 and 7.

In another preferred embodiment, the frustoconical portion is disposed at an angle to the longitudinal direction of the container, said angle being greater than 20 °, preferably greater than 30 °, more preferably greater than 40 °, most preferably greater than 50 °.

In a further preferred embodiment, the frustoconical portion extends at an angle to the longitudinal direction of the container, said angle being less than 80 °, preferably less than 70 °.

In a further preferred embodiment, the ratio of the base ring diameter to the outer diameter of the container is greater than 0.600, preferably greater than 0.610, preferably greater than 0.615, preferably greater than 0.620, preferably greater than 0.625, particularly preferably greater than 0.63.

In another preferred embodiment, the ratio of the base ring diameter to the outer diameter of the container is less than 0.85, preferably less than 0.845, preferably less than 0.840, preferably less than 0.835, preferably less than 0.825, preferably less than 0.82, preferably less than 0.81, preferably less than 0.80, preferably less than 0.79, preferably less than 0.78, particularly preferably less than 0.77.

The utility model also relates to a mould, in particular a blow mould, which is suitable for and intended for forming the plastic container described above. It is particularly preferred that the mold or blow mold is designed with at least three parts, and particularly preferably with at least two side parts and one bottom part. Particularly preferably, the bottom portion is adapted for manufacturing the bottom of the plastic container described above.

Other advantages and embodiments of the utility model are detailed in the accompanying drawings.

Drawings

FIG. 1 is a schematic view of a plastic container provided by the present utility model;

FIG. 2 is a cross-sectional view of the plastic container of FIG. 1;

FIG. 3 is a bottom view of the plastic container of FIG. 1;

FIG. 4 is a schematic view in partial section of the bottom of a plastic container;

FIG. 5 is another schematic cross-sectional view of the bottom of the plastic container;

FIG. 6 is another schematic view of the bottom;

FIG. 7 is another schematic view of the bottom;

FIG. 8 is a bottom cross-sectional view;

FIG. 9 is another cross-sectional view of the bottom portion;

FIG. 10 is a bottom view of a plastic container provided by the present utility model;

FIG. 11 is a cross-sectional view of a stiffening rib;

FIGS. 12a, b are two schematic diagrams of the angular relationship of the stiffening ribs;

fig. 13a, b are two further schematic views of the geometry of the stiffening rib;

FIG. 14 is another schematic view of a stiffening rib;

FIGS. 15a-15c are three schematic views of the bottom;

fig. 16a-16c are three more schematic views of the bottom.

Detailed Description

Fig. 1 shows a front view of a plastic container 1 provided by the present utility model. The plastic container 1 has a bottom 2, a base 6 and a mouth 8. Reference numeral 18 denotes a screw thread or a screw thread portion having an opening through which liquid can be filled into the container 1 or can be taken out from the container 1.

Reference L indicates the longitudinal direction of the container, the base 6 being arranged above the bottom and the mouth 8 being arranged above the base 6. Preferably, the volume of the container is between 0.3L and 5L, preferably between 0.5L and 3L, and preferably between 0.5L and 2L.

Reference numeral 32 denotes a bottom surface or base ring of the container. The bottom surface is preferably perpendicular to the longitudinal direction L.

Fig. 2 shows a cross-sectional view of the container shown in fig. 1. The longitudinal direction L is also shown in fig. 2. Reference numeral 20 denotes an arched or dome-shaped portion within the base. Thus, the present utility model provides a container wherein the base is designed to resemble a champagne base.

Fig. 3 shows a view of the bottom 2 of the container. The central region 22 can be seen to which the frusto-conical portion 24 is connected. Reference numeral 26 denotes a stepped portion connecting the truncated conical portion 24 to the bottom surface 32. It can be seen that the bottom surface 32 is truncated by a plurality of grooves.

Fig. 4 shows a more detailed cross-sectional view of the container bottom provided by the present utility model. It can be seen here that the basic contour of the base 2 is described by the central region 22, which in cross section is designed as a central straight line, the transition curve or circular arc 23, the frustoconical portion 24, the first curved portion 260, the frustoconical portion 24, by means of the first curved portion 260, transitioning to a first intermediate straight line portion 262, a further curved portion 264, which transitions to an intermediate straight line portion 266 and a further curved portion 268, which transitions to a third intermediate straight line portion 270.

These separate portions together form a stepped portion 26. The outer surface of the bottom, i.e. the bottom geometry, is produced by rotation about the rotation axis (longitudinal direction L) on the profile shown in fig. 4.

The respective arcuate transitions or transitions from the straight line 22 to the frustoconical portion 24, the transition between the curved region 23 to the frustoconical portion 24, and the transition between the respective intermediate straight line portions 262, 266, and 270 and the base 32 are preferably tangentially continuous, respectively. The transition from the root arc 34 to the spline 36 may be curvature continuous, but at least tangent continuous.

The spline 36 preferably transitions continuously in curvature to the outer diameter 40, and further preferably transitions continuously at least tangentially.

As mentioned above, the curvature profile of the spline 36 in the cross section is preferably described by an n-degree polynomial, where n of the polynomial may be between 2 and 7.

Fig. 5 shows a further illustration of the bottom, also showing the trend of the curved portions 260, 264 and 268.

Fig. 6 shows a further illustration of the geometry of the bottom, the outer dimensions of which are determined by the outer diameter (2 times the outer diameter 121 and the bottom height 120). Reference numeral 122 denotes a base ring radius, and the size of the base ring radius is determined by its ratio to the outer diameter 121. Preferably, the ratio may vary between 0.615 and 0.835, preferably between 0.63 and 0.77.

Reference numeral 123 denotes the height of the truncated cone portion 24, and 131 denotes the radius dimension of the truncated cone. Both the height of the frustoconical portion and the radial dimension of the frustoconical are described by their different ratios to the outer diameter 121.

The starting point H of curve 34 is determined by the straight line between F and G. The straight line FG is preferably tangential to the root arc.

The starting point H of the curve 34 may be determined by the angle 140 on the root arc 34 between points E and G (fig. 6 and 7).

The straight line 32 is defined by points E and D (fig. 7). Line 32 is defined by dimension 130 and angle 141. The size 130 may range between 0.001mm and 5mm, and preferably between 0.01mm and 3.0 mm. Preferably, angle 141 is between 0 ° and 20 °, preferably between 1 ° and 7.5 °, and more preferably between 1.75 ° and 5 °.

The line 270 is defined by points D and C (fig. 7). Which is determined by dimension 126 and angle 142. Preferably, angle 142 is between 0.0 ° and 30 °, preferably between 0 ° and 15 °.

Line 266 is determined by points C and B (see fig. 7). Which is determined by dimension 129 and angle 143. The angle 143 may be between 0 ° and 85 °, preferably between 45 ° and 80 °, and preferably between 55 ° and 75 °. However, it is also conceivable that the angle 141 and the angle (90 ° -143) have the same magnitude.

Straight line or straight line segment 262 is defined by points B and a (see fig. 7). Which is determined by dimension 127 and angle 144. The angle 144 is preferably between 0 ° and 60 °, preferably between 0 ° and 45 °.

However, it is also conceivable that angle 144 and angle 142 have the same value.

The angle of the cross-sectional straight line portion 24 defined by point a and intersection point J (fig. 6 and 7) is determined by the height 123 of the straight line portion or central region 22, or point K and intersection point J. Preferably, the relevant angle 145 is between 45 ° and 87 °, preferably between 55 ° and 75 °.

The dimensions 130 and 129 and the length of the cross-sectional lines 266 and 32 may be varied and/or adjustable. In a first variation, dimension 129 and dimension 130 are the same. In a second variation, dimension 129 is less than dimension 130, and in a third variation, dimension 129 is greater than dimension 130.

There may also be the same combination of dimensions 125 and 127 as dimension 129 and dimension 130. Furthermore, lines 262 and 266 may have the same combinations as described above.

In addition, the length or size of portions 124 and 126 may also be related to bottom height 120 or bottom outer diameter 121. Figures 8 and 9 show two variants of the bottom. It can be seen that in the variant shown in fig. 9, the frustoconical portion 24 runs much steeper than in the variant shown in fig. 8.

Fig. 10 shows a further illustration of the container bottom 2. Five ridges or grooves 42 are provided on the bottom 2 in the figure, the five ridges or grooves 42 in the figure extending in a radial direction towards the injection point 25.

Fig. 11 shows another embodiment of such a bottom.

Fig. 12a and 12b show the guiding profile of the groove or ridge. The guiding profile of the groove is described by a straight line 53 (see fig. 12 a) and by points L and M (fig. 12 a) and an arc 52 (fig. 12 a). The straight line 53 is preferably tangent to the circular arc 52 at point M.

The arc 52 preferably intersects the spline curve 9 (see fig. 12 a) at a point M. The arc 52 is preferably tangential to an auxiliary straight line 54, the height of the auxiliary straight line 54 being set by the dimension 51. The intersection point L of line 53 with line 24 may be set between points J and P by an angle 50.

Fig. 13a and 13b show the cross-sectional profile of the groove. In principle, there can be a number of variants of the cross-sectional profile, such as trapezoidal profile, circular profile, elliptical profile, triangular profile, rectangular profile, etc.

As mentioned above, the grooves or ridges are evenly distributed over the circumference of the bottom. The number of grooves on the circumference may vary between 2 and 8, preferably between 3 and 6.

Fig. 13a shows a triangular profile with smooth sides. The isosceles triangle profile with smooth sides in the figure is defined by a circular arc 60, a height 62 and an opening angle 61. Preferably, the opening angle is between 50 ° and 130 °, preferably between 60 ° and 90 °. Preferably, the triangular profile is formed at a point R, preferably perpendicular to the guiding profile along the point to form a volume with the groove profile RK (see fig. 13 b) and subtracting the groove profile RK from the outer profile AK (see fig. 13 b). Fig. 14 shows a triangular profile with curved sides. The triangular profile is defined by circular arcs 70, 71, 72 and a height 75. It is furthermore defined by opening angles 73 and 74. The opening angle 73 may be between 0 ° and 85 °, preferably between 20 ° and 78 °.

The opening angle 74 may take a value between 20 ° and 150 °, preferably between 45 ° and 90 °.

The triangular profile is formed at a point R, preferably perpendicular to the guiding profile along this point, to form a volume with a groove profile RK, and the groove profile RK is subtracted from the outer profile AK.

Figures 15a-15c and 16a-16c show three embodiments of the bottom, respectively. These embodiments differ in the different heights of the dome-like structures.

The applicant reserves the right to claim all features disclosed in the application document as important features of the utility model, whether alone or in combination, as long as these features are new in comparison with the prior art. It is also noted that the various figures also describe features that may themselves be advantageous. Those skilled in the art will certainly appreciate that the particular features depicted in the figures may be independently preferred without requiring the use of other features in the figures. Furthermore, those skilled in the art will appreciate that the preferred embodiments may also come from a combination of several features shown in the individual figures or in different figures.

Claims (27)

1. Plastic container (1) for containing a liquid, the plastic container (1) having a bottom (2), the bottom (2) having an at least partially encircling bottom surface (32), the plastic container (1) having a base body (6) connected to the bottom (2) in a longitudinal direction (L), the base body (6) forming an inner volume (10) of the plastic container (1), in which inner volume (10) a liquid can be contained, and the plastic container (1) having a mouth (8) through which the liquid can be filled into the plastic container (1), an arch (20) being formed in the bottom (2) which is curved in the direction of the inner volume (10), the arch (20) having a central region (22), characterized in that the arch (20) has a truncated conical portion (24) arranged outside the central region in the radial direction of the plastic container and at least one circumferential stepped portion (26) and/or the arch (20) has at least two circumferential stepped portions (26).

2. Plastic container (1) according to claim 1, characterized in that the circumferential stepped portion (26) is formed between the truncated conical portion (24) and the bottom surface (32) in the circumferential direction.

3. Plastic container (1) according to claim 1, characterized in that the bottom surface (32), the circumferential frustoconical portion (24) and/or the stepped portion (26) have a circular cross-section in a plane perpendicular to the longitudinal direction (L).

4. A plastic container (1) according to claim 1, wherein the central region (22) is circular.

5. Plastic container (1) according to claim 1, characterized in that at least two grooves and/or ridges (42) extending in the radial direction R of the plastic container (1) are formed in the frustoconical portion (24) and/or the bottom surface (32) and/or the stepped portion (26) in the circumferential direction.

6. Plastic container (1) according to claim 1, characterized in that at least two grooves and/or ridges (42) extending in the radial direction R of the plastic container (1) are formed in the frustoconical portion (24) or bottom surface (32) or stepped portion (26) in the circumferential direction.

7. Plastic container (1) according to claim 1, characterized in that at least two grooves and/or ridges (42) extending in the radial direction R of the plastic container (1) are formed in the frustoconical portion (24) and bottom surface (32) in the circumferential direction.

8. Plastic container (1) according to claim 1, characterized in that at least two grooves and/or ridges (42) extending in the radial direction R of the plastic container (1) are formed in the frustoconical portion (24) and stepped portion (26) in the circumferential direction.

9. Plastic container (1) according to claim 1, characterized in that at least two grooves and/or ridges (42) extending in the radial direction R of the plastic container (1) are formed in the circumferential bottom surface (32) and stepped portion (26).

10. Plastic container (1) according to claim 1, characterized in that at least two grooves and/or ridges (42) extending in the radial direction R of the plastic container (1) are formed in the frustoconical portion (24) and bottom surface (32) and stepped portion (26) in the circumferential direction.

11. Plastic container (1) according to claim 1, characterized in that the stepped portion (26) allows the arch (20) to be moved relative to the base body.

12. Plastic container (1) according to claim 11, characterized in that the stepped portion (26) allows the arch (20) to be movable in a longitudinal direction (L) with respect to the base body.

13. Plastic container (1) according to claim 1, characterized in that the material thickness of the plastic material in the stepped portion (26) is different from the material thickness of the frustoconical portion (24).

14. Plastic container (1) according to claim 1, characterized in that the stepped portion (26) has at least two opposite curved portions (260, 264), the two curved portions (260, 264) being connected by a further straight portion (262).

15. The plastic container (1) according to claim 14, characterized in that either one of the two curved portions (260, 264) is followed by a further intermediate straight portion (266) and a further curved portion such that the curvature of the further curved portion is opposite to the curvature of one of the two curved portions (260, 264).

16. Plastic container (1) according to claim 8, characterized in that the stepped portion (26) has four curved portions (260, 264, 268, 274) between which are respectively arranged intermediate straight portions (262, 266, 270), wherein adjacent two of the curved portions are respectively curved in opposite directions.

17. A plastic container (1) according to claim 8, wherein the bottom surface (32) is directly connected to the curved portion of the stepped portion (26).

18. Plastic container (1) according to claim 1, characterized in that the bottom is transitioned into the base body (6) by a spline curve (36).

19. Plastic container (1) according to claim 18, characterized in that the curvature profile of the spline curve (36) is determined by an n-degree polynomial.

20. Plastic container (1) according to claim 19, characterized in that the degree of the n-degree polynomial is between 2 and 7.

21. A plastic container (1) according to claim 1, wherein the frustoconical portion (24) extends at an angle to the longitudinal direction (L), said angle being greater than 20 °;

and/or the frustoconical portion (24) extends at an angle to the longitudinal direction (L), said angle being less than 80 °.

22. A plastic container (1) according to claim 21, wherein the angle is greater than 30 °;

and/or the angle is less than 70 °.

23. A plastic container (1) according to claim 21, wherein the angle is greater than 40 °.

24. A plastic container (1) according to claim 21, wherein the angle is greater than 50 °.

25. A plastic container (1) according to claim 1, characterized in that the ratio of the base ring diameter to the outer diameter of the plastic container is 0.615-0.835.

26. A plastic container (1) according to claim 1, characterized in that the ratio of the base ring diameter to the outer diameter of the plastic container is 0.63-0.77.

27. A mould for producing a plastic container according to any one of claims 1 to 26, characterized in that the mould is a blow mould.