EP4159629A1 - Plastic container with stable base design - Google Patents

Abstract

Plastic container (1) for holding liquids and in particular beverages, with a base section (2) which forms an at least partially circumferential standing surface (32), with a base body ( 6), which forms an inner volume (10) of the plastic container (1), within which the liquid can be accommodated, and with a mouth section (8) with a mouth via which a liquid can be filled into the plastic container (1), with the bottom section (2) a curved structure (20) is formed in the direction of the inner volume, this curved structure (20) having a central area (22), characterized in that the curved structure (20) has a peripheral frustoconical section (24) which in is arranged in a radial direction of the plastic container outside the central area and has at least one circumferential step-like section (26) and/or the arched structure (20) has an at least two-stage circumferential step-like section (26).

Description

The following invention relates to a plastic container and in particular a container made of PET, which is used to hold liquids and in particular beverages. Numerous plastic containers are known from the prior art. These differ from one another in many respects, for example the geometry of the bottom of the container, the geometry of the mouth or the filling volume and the like. Particular difficulties are associated with containers that have to withstand a high internal pressure, for example for carbonated drinks. In particular, the bottoms of such containers are often subjected to high loads, and the high internal pressure can cause the bottom to deform, which impairs the stability of the container.

The present containers should withstand a pressure that reaches, for example, up to 5 bar or up to 8.4 bar. It should preferably be possible to fill the containers in quantities of between 200 ml and 5 l.

In addition, a container is also to be made available which enables the bottom geometry to be shaped more effectively.

Containers are known from the prior art which have a champagne base which has a hemisphere-like depression with a surrounding standing circle. With this floor, it is very difficult to achieve a homogeneous material distribution in the standing area of the base, since this can no longer be achieved by a small offset of a plastic preform in relation to the center of the base when blowing the bottle. This then leads in part to a greater deviation in the plumbness of the container.

A plastic container according to the invention for holding liquids and in particular beverages has a base section which forms an at least partially encircling standing surface. Furthermore, a base section adjoins a base section in a longitudinal direction of the container, which forms an inner volume of the plastic container, within which the liquid can be accommodated. Furthermore, the container has a mouth section with a mouth, via which a liquid can be filled into the plastic container. In this case, this opening preferably has a smaller cross section than the base body.

Furthermore, a structure or dome-like structure curved in the direction of the interior volume is formed in the base section, this curved structure having a central area.

According to the invention, the arched structure has, at least in sections, a circumferential frustoconical section, which is arranged in a radial direction of the plastic container outside the central region, and at least one step-like section, which is also circumferential.

In a further configuration according to the invention, the arched structure has an at least two-stage circumferential step-like section.

Both measures according to the invention result in a high stability of the plastic container while at the same time compensating for pressure differences. The arched structure preferably has both a peripheral truncated cone shape and an at least two-stage peripheral step-like section. The combination of these two configurations achieves a stable base section which nevertheless has options for compensating for pressure differences.

A partially encircling footprint is understood to mean a footprint that extends around the longitudinal direction of the container. This can be designed to be completely circumferential or uninterrupted, or it can also be interrupted by grooves, which are described in more detail below.

The standing surface is preferably ring-shaped (disregarding the grooves or webs).

The section is preferably a truncated cone-shaped termination, which is particularly preferably terminated by the central area. The frustoconical section preferably adjoins the central area via a curved section. The central area is preferably designed to be rotationally symmetrical. The central area is preferred. In a further preferred embodiment, the central area has a circular cross section.

The step-like section preferably has at least two oppositely curved sections. The step-like section particularly preferably has at least three curved sections, the sections with different and in particular opposite curvatures being arranged one behind the other. Sections with a rectilinear course are preferably arranged between these curved sections.

A section of the container in a plane containing the longitudinal direction or a central axis of symmetry of the container is assumed to describe the individual courses.

In a further preferred embodiment, the step-like section has at least four curved sections, the sections with different curvatures preferably being arranged one behind the other, so that, for example, in the first section there is a positive curvature, in the second section a negative curvature, and in the third section again one positive curvature and a negative curvature is provided in the fourth section.

The arched structure is preferably described in this way. This is composed (from inside to outside) of the central section, which preferably has a horizontal cross-section running straight line, then a radius or a curve, then another straight line (which forms the frustoconical section), then the step-shaped section (which has several curved sections and preferably straight sections between them) and a root radius or a curve in the standing section . This in turn can be followed by a spline (as explained in more detail below).

The step-like section does not have to form horizontal steps, but these can be angled at a predetermined angle with respect to the horizontal direction. The connections between two such steps do not have to be vertical either, but can also be inclined at a predetermined angle with respect to the vertical direction.

From this contour, which is shown in more detail below, the so-called outer surface of the floor geometry is generated by a rotation around the longitudinal direction or around the axis of rotation. The transitions between the radii, the straight line and the radius as well as the rear foot radius are preferably at least isolated and preferably all tangent-constant. As explained in more detail below, the transition from the root radius to the spline can be curvature-continuous, but is preferably at least tangent-continuous.

The spline preferably merges into the outer diameter of the container.

In a further preferred embodiment, the encircling step-like section is formed between the encircling conical or frustoconical section and the standing surface. This step-like section serves to absorb deformations, for example when the filling product develops an internal pressure.

In a further preferred embodiment, the base, the peripheral frustoconical section and/or the step-like section has a circular cross-section in one plane, preferably in several such planes and particularly preferably in all planes to which the longitudinal direction is perpendicular. In this case, this circular cross section is preferably designed to be rotationally symmetrical. However, grooves or webs can also run in this cross section, as will be explained below.

In a further preferred embodiment, the central area has a circular shape. An injection point of the container is particularly preferably arranged within this central area (this injection point is due to the formation of the associated plastic preforms).

Particularly preferably, this central area extends horizontally in a radial direction of the container (observed with an upright container).

The central area is preferably designed to be rotationally symmetrical with respect to the longitudinal direction of the plastic container.

In a further preferred embodiment, at least two grooves and/or webs extending in the radial direction of the plastic container are formed in the circumferential conical section and/or the base and/or the step-like section.

These webs preferably serve as tension straps and in particular to stabilize the bottom section. At least 3, preferably at least 4 and preferably at least 5 such grooves or tension bands are preferably provided.

In a further advantageous embodiment, a maximum of 12, preferably a maximum of 10, preferably a maximum of 8, preferably a maximum of 7 and preferably a maximum of 6 such webs are provided. These webs or tension bands are preferably distributed essentially uniformly in a circumferential direction of the base section.

In a preferred embodiment, these webs interrupt the footprint of the plastic container. Viewed from below, the webs are preferably designed as grooves or recesses. The grooves preferably protrude in the direction of the interior volume of the container.

In a further preferred embodiment, the grooves and/or ridges also extend into the frusto-conical section mentioned.

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

These webs and/or drawstrings preferably extend in the radial direction by a predetermined proportion in the radial direction of the conical section in the direction of the center of the container. This section is preferably at least 10% of the total radial extent, preferably at least 15%, in the radial direction (or in the direction in which the frustoconical section extends). In a further preferred embodiment, this section extends at most 80%, preferably at most 70% and preferably at most 60% in the radial direction (and/or the direction of extent) of the frustoconical section.

In a further preferred embodiment, the stepped section allows a relative movement of the arched structure or dome-like structure with respect to the base body, in particular in the longitudinal direction of the container. It is possible that the step-like section allows a movement of the arched structure (and the central area) in its entirety. In this way, springing or a relative movement of the conical section can be achieved by the step-shaped section and thus, within certain limits, an increase or decrease in volume of the interior of the container. In this way, higher pressures or negative pressures (which can arise, for example, when a beverage that has been filled hot) can be compensated for.

In a further preferred embodiment, a material thickness of the plastic material in the step-like section differs from a material thickness in the conical section and/or the base body.

It is thus possible for a material thickness of the plastic container to be greater in the area of the stepped section than in the frustoconical section and/or the base body. The material thickness of the plastic container in the stepped section is preferably at least 5% greater than the material thickness in the base body and/or the frustoconical section, preferably at least 10% greater, preferably at least 15% greater and preferably at least 20% greater.

The material thickness of the plastic container in the stepped section is preferably at most 70% greater than the material thickness in the base body and/or the truncated cone Section, preferably at most 60% larger, preferably at most 50% larger and preferably at most 40% larger.

In a further preferred embodiment, the step-like section has at least two sections curved in opposite directions, which are connected to one another by a further section or intermediate section. This further section particularly preferably extends in a straight line and/or has a radius of curvature that is at least 5 times as large as a radius of curvature of the curved sections, preferably at least 10 times as large and preferably at least 20 times as large, preferably at least 30 times as large .

At least one of said curved sections preferably has a radius of curvature which is greater than 0.2 mm. Preferably, at least one of said curved sections has a radius of curvature that is less than 3.0 mm.

This step-like section is viewed in particular in a cross-sectional direction which is perpendicular to the longitudinal direction of the container or in a plane which contains the longitudinal direction (and in which none of the mentioned grooves are arranged).

In a further preferred embodiment, one of the curved sections is followed by a further intermediate section and preferably a further curved section, in particular such that a curvature of this further curved section runs in contrast or opposite to the curvature of the first mentioned section.

Particularly preferably, this further intermediate section is also straight or has a radius of curvature that is at least 5 times as large as the radius of curvature of the aforementioned curved sections, preferably at least 10 times as large and particularly preferably at least 20 times as large.

In a further preferred embodiment, the step-like section has four curved sections, between which rectilinear or essentially rectilinear sections are arranged, with preferably two consecutive curved sections each being curved in opposite directions.

A step-like section with a total of at least two steps is therefore described in this embodiment.

In a further advantageous embodiment, the standing surface adjoins a curved section of the stepped section (in particular directly). In a further preferred embodiment, the base body section merges into the base body via a connecting section, with this connection section being particularly preferably designed as a spline, and with a curvature of this spline being particularly preferably expressed by a polynomial of the nth degree, with this degree preferably being between 2 and 7 lies.

In a further advantageous embodiment, the frustoconical section is arranged at an angle to the longitudinal direction of the container which is greater than 20°, preferably greater than 30°, preferably greater than 40°, preferably greater than 50°.

In a further preferred embodiment, the frustoconical section is arranged at an angle relative to the longitudinal direction or runs at an angle which is less than 80°, preferably less than 70°.

In a further preferred embodiment, a ratio between a base circle diameter and an 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 and particularly preferably greater than 0.63.

In a further preferred embodiment, a ratio between a base circle diameter and an 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 less than 0.81, preferably less than 0.80, preferably less than 0.79, preferably less than 0.78 and particularly preferably less than 0.77.

The present invention is further directed to a mold, and in particular a blow mold, suitable and intended for forming a plastics container of the type described above way to train. This mold or blow mold is particularly preferably designed in at least three parts and particularly preferably has at least two side parts and one base part. A base part is particularly preferably used to produce the base section of the plastic container described here.

Fig. 1

eine schematische Darstellung eines erfindungsgemäßen Kunststoffbehältnisses;

Fig. 2

eine Schnittdarstellung des in Fig. 1 gezeigten Kunststoffbehältnisses;

Fig. 3

eine Ansicht auf den Boden des in Fig. 1 gezeigten Kunststoffbehältnisses;

Fig. 4

eine teilweise Darstellung eines Schnitts des Kunststoffbehältnisses;

Fig. 5

eine weitere Darstellung eines Schnitts des Kunststoffbehältnisses;

Fig. 6

eine weitere Darstellung zur Erläuterung des Bodenabschnitts;

Fig. 7

eine weitere Darstellung zur Erläuterung des Bodenabschnitts;

Fig. 8

eine Schnittdarstellung eines Bodenabschnitts;

Fig. 9

eine weitere Schnittdarstellung eines Bodenabschnitts;

Fig. 10

eine Ansicht des Bodenabschnitts des erfindungsgemäßen Kunststoffbehältnisses;

Fig. 11

eine Schnittdarstellung zur Veranschaulichung der Zugbänder;

Fig. 12a, b

zwei Darstellungen zur Veranschaulichung von Winkelverhältnissen;

Fig. 13a, b

zwei weitere Darstellungen zur Veranschaulichung der Zugbandgeometrie;

Fig. 14

eine weitere Veranschaulichung zur Darstellung der Zugbänder;

Fig. 15a-15c

drei Darstellungen eines Bodenteils bzw. Bodenabschnitts;

Fig. 16a-16c

drei weitere Darstellungen eines Bodenabschnitts.

Further advantages and embodiments result from the attached drawings:
Show in it:

1

a schematic representation of a plastic container according to the invention;

2

a sectional view of the in 1 shown plastic container;

3

a view of the bottom of the in 1 shown plastic container;

4

a partial representation of a section of the plastic container;

figure 5

another representation of a section of the plastic container;

6

another illustration to explain the bottom section;

7

another illustration to explain the bottom section;

8

a sectional view of a bottom portion;

9

another sectional view of a bottom section;

10

a view of the bottom portion of the plastic container according to the invention;

11

a sectional view illustrating the drawstrings;

12a, b

two representations to illustrate angular relationships;

13a, b

two further representations to illustrate the drawstring geometry;

14

another illustration showing the drawstrings;

Figures 15a-15c

three representations of a floor part or floor section;

Figures 16a-16c

three more depictions of a section of soil.

figure 1 shows a front view of a plastic container 1 according to the invention. This plastic container 1 has a bottom section 2, a base body 6 and a mouth section 8. The reference number 18 denotes a thread or a threaded section with an opening through which liquid fills in or out of the container 1 can be taken from this.

The reference character L designates a longitudinal direction of the container in which the base body 6 is arranged above the base section and the mouth section 8 is arranged above the base body. The container preferably has a volume content of between 0.3l and 5l, preferably between 0.5l and 3l and preferably between 0.5l and 2l.

The reference number 32 denotes a base or a base ring of the container. This standing surface is preferably perpendicular to the longitudinal direction L.

figure 2 shows a sectional view of the in figure 1 shown container. The longitudinal direction L can also be seen here again. The reference number 20 designates the arched or dome-like section within the base section. Thus, in the case of the container according to the invention, the base section is designed like a champagne base.

figure 3 shows a view of the bottom section 2 of the container. The central area 22 can be seen here, to which the frustoconical section 24 is connected. Numeral 26 denotes a step-like portion which is the frusto-conical Section 24 with the base 32 connects. You can see that the standing surface is interrupted by a large number of grooves.

figure 4 shows a more detailed sectional view of the bottom section of a container according to the invention. It can be seen here that the base contour of the base is described by the central region 22, which is designed here in section as a central straight line, a transition curve 23 or a radius, the frustoconical section 24, a first curved section 260, with which the frustoconical section 24 transitions into an intermediate rectilinear section 262, another curved section 264 transitioning to an intermediate rectilinear section 266, and another curved section 268 transitioning to a straight section 270.

These individual sections together form the stepped section 26 . At this in figure 4 In the contour shown, the outer surface of the bottom section, ie the bottom geometry, is produced by a rotation about the axis of rotation (longitudinal direction L).

The transitions of the individual radii or from the straight line 22 to the frustoconical area 24, the transitions between the curved area 23 to the frustoconical section 24 and also the transitions between the individual straight sections 262, 266 and 270 as well as the section 32 are preferably each tangentially continuous . The transition from the root radius 34 to the spline 36 can be curvature-continuous, but at least tangent-continuous.

The spline 36 preferably merges into the outer diameter 40 with a constant curvature, but preferably at least with a constant tangent.

As mentioned above, the course of curvature of the spline 36 in the cross section is preferably described by a polynomial of the nth degree, where the nth of the polynomial can be between 2 and 7.

figure 5 FIG. 12 shows a further illustration of the base section, the further progression of the curves 260, 264 and 268 also being indicated here.

figure 6 shows a further representation of the base geometry, the outer dimensions of the base section are determined by the outer diameter (2x radius 121 and the base height 120). The reference number 122 shows the base circle radius and this is determined by a ratio to the outer diameter 121 . This ratio can preferably vary between 0.615 and 0.835, preferably between 0.63 and 0.77.

The reference number 123 denotes the height of the truncated cone or of the section 24 and the reference number 131 denotes the diameter dimension of the truncated cone. These are both described by different ratios to the outside diameter 121 .

The starting point H of the spline 34 is generated by a straight line between F and G. This straight line FG is preferably tangential to the root radius.

The starting point H of the spline can be set using an angle 140 on the root radius 34 between points E and G ( Figure 6 and 7 ) are determined.

The straight line 32 is determined by the points E and D ( 7 ). The straight line 32 is determined by the dimension 130 and the angle 141. The dimension 130 can range between 0.001 mm and 5 mm and preferably between 0.01 mm and 3.0 mm. The angle 141 is preferably between 0° and 20°, preferably between 1° and 7.5° and particularly preferably between 1.75° and 5°.

Line 270 is defined by points D and C ( figure 7 ) Are defined. This is determined with the dimension 126 and the angle 142. Preferably, the angle 142 is between 0.0° and 30°, preferably between 0° and 15°.

The straight line 266 is drawn through the points C and B (cf. figure 7 ) Are defined. This is determined with the dimension 129 and the angle 143. The angle 143 can be between 0° and 85°, preferably between 45° and 80° and particularly preferably between 55° and 75°. However, it is also conceivable that the angle 141 and an angle (90° - angle 143) are of the same size.

The straight line 262 or the straight section 262 is defined by the points B and A (cf. figure 7 ) certainly. This is defined with the dimension 127 and the angle 144. The angle 144 is preferably between 0° and 60°, preferably between 0° and 45°.

However, it would also be conceivable for the angle 144 and the angle 142 to have the same value.

The angle of straight section 24 defined by point A and intersection J ( Figure 6 and 7 ) is determined by the height 123 of the straight line or of the central area 22 or by the point K and the point of intersection J. The associated angle 145 is preferably between 45° and 87°, preferably between 55° and 75°

The lengths of gauges 130 and 129, as well as straight portions 266 and 32, may vary in length and/or are adjustable. In a first variant, the lengths or dimensions 129 and 130 are identical. In a second variant, the dimension 129 is smaller than the dimension 130 and in a third variant, the dimension 129 is larger than the dimension 130.

The same possible combinations are also possible for dimensions 125 and 127. In addition, the same possible combinations for straight lines 262 and 266 are also possible.

Furthermore, the lengths or dimensions of sections 124 and 126 can also be related to ground height 120 or ground clearance 121 . The Figures 8 and 9 show two variants of a floor section. It can be seen that in variant 9 the truncated cone-shaped section 24 runs much steeper than in figure 8 shown configuration.

figure 10 shows a further representation of the bottom section 2 of the container. Five ridges or grooves 42 are provided here, which extend here in the radial direction towards the injection point 25 .

figure 11 shows a further embodiment of such a floor section.

The Figures 12a and 12b show a guide contour of the grooves or webs. A guide contour of the grooves is defined by a straight line 53 (cf. Figure 12a ) described, as well as by the points L and M ( Figure 12a ) and the radius 52 ( Figure 12a ). The straight line 53 is preferably tangential to the radius 52 at the point M.

Radius 52 preferably intersects spline 9 (cf. Figure 12a ) at the point M. The radius 52 is preferably tangential to an auxiliary straight line 54, the height of which is adjusted via the dimension 51.

The point of intersection L of the straight line 53 with the straight line 24 can be adjusted via the angle 50 between the points J and P.

The Figures 13a and 13b illustrate the cross-sectional contour of the groove. In principle, several variants of cross-sectional contours are possible, such as a trapezoidal contour, a circular contour, an elliptical contour, a triangular contour, a rectangular contour, etc.

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

Figure 13a shows a triangular contour with smooth sides. This triangular contour with the smooth and isosceles sides is defined by the radius 60, the height 62 and the opening angle 61. This opening angle can preferably be between 50° and 130°, particularly preferably between 60° and 90°. This triangular contour is preferably at the point R perpendicular to the guide contour along this, to a volume body with a groove contour RA (cf. Figure 13b ) and formed by the outer contour AK (cf. Figure 13b ) subtracted.

figure 14 shows a triangular contour with curved sides. This triangular contour is defined by the radii 70, 71, 72 and the height 75. In addition, it is also defined by the opening angles 73 and 74. The opening angle 73 can be between 0° and 85°, preferably between 20° and 78°.

The opening angle 74 can assume values between 20° and 150°, preferably between 45° and 90°.

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

The Figures 15a-15c and 16a-16c each show three representations of the bottom section. These differ in each case by the different heights of the dome-like structure.

The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are new compared to the prior art, either individually or in combination. It is also pointed out that the individual figures also describe features which can be advantageous in and of themselves. The person skilled in the art recognizes immediately that a specific feature described in a figure can also be advantageous without adopting further features from this figure. Furthermore, the person skilled in the art recognizes that advantages can also result from a combination of several features shown in individual figures or in different figures.

Claims (15)

Plastic container (1) for holding liquids and in particular beverages, with a base section (2) which forms an at least partially circumferential standing surface (32), with a base body ( 6), which forms an inner volume (10) of the plastic container (1), within which the liquid can be accommodated, and with a mouth section (8) with a mouth via which a liquid can be filled into the plastic container (1), with the bottom section (2) a structure (20) curved in the direction of the inner volume is formed, this curved structure (20) having a central area (22),
characterized in that
the arched structure (20) has a circumferential frustoconical section (24) which is arranged in a radial direction of the plastic container outside of the central area and at least one circumferential step-like section (26) and/or the arched structure (20) has an at least two-stage circumferential step-like section Has section (26). Plastic container (1) according to claim 1,
characterized in that
the circumferential step-like section (26) is formed between the circumferential frustoconical section (24) and the standing surface (32). Plastic container (1) according to at least one of the preceding claims,
characterized in that
the base (32), the peripheral frustoconical section (24) and/or the step-like section (26) has a circular cross-section in a plane to which the longitudinal direction (L) is perpendicular. Plastic container (1) according to at least one of the preceding claims,
characterized in that
the central area (22) is circular. Plastic container (1) according to at least one of the preceding claims,
characterized in that
at least two grooves and/or webs (42) running in a radial direction R of the plastic container are formed in the circumferential frustoconical section (24) and/or the standing surface (32) and/or the step-like section (26). Plastic container (1) according to at least one of the preceding claims,
characterized in that
the step-like section (26) allows a relative movement of the arched structure (20) with respect to the base body, in particular in the longitudinal direction (L). Plastic container (1) according to at least one of the preceding claims,
characterized in that
a material thickness of the plastic material in the stepped section (26) differs from a material thickness in the frustoconical section (24). Plastic container (1) according to at least one of the preceding claims,
characterized in that
the step-like section (26) has at least two oppositely curved sections (262, 266) which are connected to one another by a further, preferably rectilinear section (264). Plastic container (1) according to the preceding claim,
characterized in that
one of the curved sections (262, 266) is followed by a further intermediate section (268) and a further curved section, such that a curvature of this further curved section is opposite to the curvature of this section (262, 266). Plastic container (1) according to at least one of the preceding claims,
characterized in that
the step-like portion has four curved portions (262, 266, 270, 274) between which are respectively arranged straight portions (264, 268, 272), wherein two consecutive curved portions are each oppositely curved. Plastic container (1) according to at least one of the preceding claims 8 - 10,
characterized in that
the standing surface (32) directly adjoins a curved section of the step-like section. Plastic container (1) according to at least one of the preceding claims,
characterized in that
the bottom section merges into the base body via a spline, with a curvature profile of this spline preferably being able to be described by a polynomial of the nth degree and the degree particularly preferably being between 2 and 7. Plastic container (1) according to at least one of the preceding claims,
characterized in that
the frustoconical section runs at an angle relative to the longitudinal direction which is greater than 20°, preferably greater than 30°, preferably greater than 40°, preferably greater than 50° and/or that the frustoconical section runs at an angle relative to the longitudinal direction, which is less than 80°, preferably less than 70°. Plastic container (1) according to at least one of the preceding claims,
characterized in that
a ratio between a base circle diameter and an outer diameter of the container is between 0.615 and 0.835 and preferably between 0.63 and 0.77. Mold, in particular blow mold for producing a container according to at least one of the preceding claims.

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