EXTRUSION BLOW-MOLDED CONTAINER AND METHOD AND BLOW MOLD FOR THE PRODUCTION THEREOF

Abstract

The invention relates to an extrusion blow-molded container, the inside of which is defined by a container side wall and a container bottom, a standing area being detachably connected to the container side wall and to the container bottom. According to the invention, at least a subarea of a bottom of a primary container product formed from the parison is irreversibly moved into the container such that an undercut container bottom is embodied on the container at least in a subarea, the standing area of the container being formed in the region of the undercut container bottom from a side wall of the primary container product by bending and/or pressing down.

Claims

1. An extrusion blow-molded container, comprising: a container having an inside defined by a container side wall and a container bottom, wherein a standing area is inseparably connected to the container side wall and to the container bottom, and at least a partial region of a bottom of a container precursor formed from a preform irreversibly moved into the container such that an undercut container bottom formed on the container at least in a partial region, the standing area of the container being formed in the region of the undercut container bottom from a side wall of the container precursor by bending or upsetting.

2. The container as claimed in claim 1, wherein at least one partial region of a section of the container side wall adjoining the undercut container bottom is substantially perpendicular to a plane subtended by the standing area.

3. The container as claimed in claim 1, wherein the standing area has a thickness that is equal to or greater than a wall thickness of the container side wall.

4. The container as claimed in claim 1, wherein the container bottom and the container side wall make an angle that is equal to or less than 45.

5. The container as claimed in claim 1, wherein the side wall of the container precursor is folded to create the standing area of the container, forming an edge.

6. The container as claimed in claim 1, wherein the container side wall and the container bottom extend parallel to each other in at least one other partial region.

7. The container as claimed in claim 6, wherein the container side wall and the container bottom at least partly touch each other or are at least partly welded to each other in the at least one other partial region.

8. The container as claimed in claim 1, wherein the standing area tapers to a point.

9. The container as claimed in claim 1, wherein the standing area is encircling.

10. The container as claimed in claim 1, wherein the standing area is divided by at least two setbacks that are spaced apart from each other.

11. The container as claimed in claim 1, wherein the container bottom bulges outward in a convex manner and is set back from a plane subtended by the standing area.

12. The container as claimed in claim 1, wherein a spacing of the container bottom from a plane subtended by the standing area substantially increases continuously from a first container side wall to a second container side wall standing opposite the first container side wall.

13. The container as claimed in claim 1, wherein the container is made as a single piece of plastic.

14. The container as claimed in claim 1, wherein a top side of the container standing opposite the container bottom has a shape corresponding to the container bottom or the top side of the container can be received in the container bottom of an identical container, so that a plurality of containers can be stacked on each other.

15. A method for producing a container by extrusion blow molding, an inside of the container being defined by a container side wall and a container bottom, wherein a standing area is inseparably connected to the container side wall and to the container bottom, comprising: introducing a preform into a cavity of an opened blow mold; closing the blow mold and securing the preform in the cavity; introducing gas under pressure into the preform, so that a wall of the preform is pressed against an inner wall of the cavity to create a container precursor with a bottom and a side wall; displacing of a displaceable slide of the blow mold from a first position, in which the bottom of the container precursor was formed, to a second position, in which at least a partial region of the bottom is moved irreversibly into the container in such a way that an undercut container bottom is formed on the container at least in a partial region, the standing area of the container being formed in the region of the undercut container bottom from a side wall of the container precursor by bending or upsetting.

16. The method as claimed in claim 15, further comprising closing the blow mold during the moving of the slide from the first position to the second position.

17. The method as claimed in claim 15, wherein the slide is free of structures enlarging its circumference.

18. The method as claimed in claim 15, further comprising opening the blow mold for the movement of the slide from the first position by 1 mm and closing the blow mold after reaching the second position.

19. The method as claimed in one of claim 15, wherein the moving of the slide from the first position to the second position folds a partial region of the side wall adjoining the bottom of the container precursor, creating an edge.

20. The method as claimed in one of claim 15, further comprising extending a partial region of the container bottom substantially parallel to the container side wall.

21. The method as claimed in claim 15, wherein the standing area of the container subtends a plane, wherein a lowest point of the container bottom of the container precursor is pushed by the slide so far into the container that the lowest point is set back into the container as compared to the plane.

22. A blow mold, comprising: a molding cavity to produce a container by extrusion blow molding, an inside of the container being defined by a container side wall and a container bottom, wherein a standing area is inseparably connected to the container side wall and to the container bottom, and a slide displaceable from a first position into the molding cavity into a second position, and vice versa, defines in the first position a shape of a bottom of a container precursor and in the second position a shape of an undercut container bottom of the finished container.

23. The blow mold as claimed in claim 22, wherein an end face of the movable slide is concave in shape, while in the first position only the end face of the slide defines the shape of the container bottom of the container precursor and in the second position the end face together with an adjoining substantially cylindrical side wall of the slide defines the shape of the undercut container bottom of the container.

24. The blow mold as claimed in claim 22, wherein the slide is spaced away from an inner wall of the molding cavity such that at least a partial region of a side wall of the container precursor is bendable, foldable, or upsettable during movement of the slide from the first position to the second position.

25. The blow mold as claimed in claim 24, wherein the slide is arranged on a first part of a movement distance between the first position and the second position at a greater lateral spacing from the inside of the molding cavity than on a second part of the movement distance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] There are shown in schematic representation, not true to scale:

[0070] FIG. 1a a container in perspective view from above;

[0071] FIG. 1b the container of FIG. 1a in perspective view from below;

[0072] FIG. 2a a side view of two containers stacked on one another;

[0073] FIG. 2b a side view of a container with submerged pipe;

[0074] FIG. 2c a side view of a container with additional product;

[0075] FIG. 2d a side view of a container with a hand-operated pump and submerged pipe as well as a bottom dropping off toward the edge;

[0076] FIG. 3a a longitudinal section through a blow mold with a movable slide in a first position; and

[0077] FIG. 3b the blow mold of FIG. 3a with a movable slide in a second position.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0078] The invention shall now be explained as an example with the aid of the drawings.

[0079] FIG. 1a and 1b show a container 11 with a container side wall 31 and a container bottom 21, the material of the container side wall 31 passing smoothly and without interruption into the material of the container bottom 21. The transition has the shape of an edge 29. The edge was created by folding of a side wall of a container precursor and it forms the standing area of the container 11. The edge 29 extends along the entire circumference of the container bottom 21 and subtends a plane by which the container 11 can be placed in stable position standing on the edge.

[0080] Basically, it is also possible alternatively or additionally to form two (a third placement point could then form the edge), three or more standing feet along the margin of the container 11, especially along the edge 29, with the placement points of the standing feet (i.e., the points of contact with a surface) being situated in a plane.

[0081] In the present example, the container bottom 21 starts from the edge 29 and extends up to a distance of, for example, 1 to 2 centimeters from the edge 29 parallel to the container side wall 31 and it is advisedly welded to the latter. In this way, a double-wall region 30 of the container 11 is formed, which extends along the entire circumference of the container 11 and stiffens the lower region of the container 11. At least the double-wall region 30 is formed as a straight cylinder casing or a straight prismatic casing, which is substantially perpendicular to the plane subtended by the edge 29, at the same time forming the standing area. The container bottom 21 starting from the edge 29 extends parallel to the container side wall 31, then moves away from the container side wall 31 and extends in the direction toward a container longitudinal axis, while extending at the same time toward the plane defined by the edge 29 (i.e., downward), but without passing through said plane. In this way, the container bottom 21 has the shape of a shell, making it easier to empty remaining product from the container 11.

[0082] An alternative in which the container bottom 21 does not drop toward the standing area is shown in FIGS. 2a and 2c. Furthermore, the distance up to which the container bottom 21 extends starting from the edge 29 and parallel to the container side wall 31 may also be shorter on one side of the container 11 than on the opposite side and/or on the rest of the circumference. In particular, the distance from said point to the opposite side of the container 11 may increase. In this way, the lowest point of the inside of the container bottom 21 coming into contact with the product lies not in the middle of the container bottom 21, as shown in FIGS. 1b and 2b, but instead on one side of the container 11, as is shown for example in FIG. 2d. In containers 11 having a submerged pipe 43 to deliver the product from the container 11, such as the container shown for example in FIG. 2d with hand-operated dispensing or spray pump and a submerged pipe 43 connected to it, this may be advantageous for the emptying of remaining product.

[0083] The cavity 27 bounded by the double-wall region 30 on the underside of the container 11 affords room for an outwardly pointing indentation 23 of the container bottom 21 per FIG. 1b and 2b, but alternatively or additionally it may also serve to accommodate an additional product 15, such as a sponge, a pamphlet, or the like, as shown for example in FIG. 2c. The cavity 27 may also be formed alternatively or additionally to accommodate a top side of an identical container 11 and thereby make it possible to stack such containers, as illustrated in FIG. 2a. Advisedly, the top side of the container 11 will have a shape corresponding to the bottom side and/or to the container bottom 21 of the container 11. The bottom side and/or the container bottom 21 of a container 11 may accommodate for example the pour opening 39 and the region from the pour opening 39 to the shoulder 37 of the container 11, so that the edge 29 of the upper container 11 rests against the shoulder 37 of the lower container 11.

[0084] FIGS. 3a and 3b illustrate a portion of the method for making a container 11 per FIG. 1a and 1b. As is known, in extrusion blow molding a preform in the form of an extruded tube is first blow molded in a cavity 53 of a blow mold 51, whereupon the preform takes on the shape of the cavity 53 externally. This condition is shown in FIG. 3a, where the blow-molded preform after completion of the expansion of the preform produced by blowing a gas, especially air, into the cavity and/or at maximum extension of the preform is known as the container precursor 13. In addition, it should be pointed out that in a conventional extrusion blow molding, this container designated as the container precursor 13 represents the end product intended for stripping from the mold.

[0085] This container precursor 13, having a side wall 33 and a bottom 22, is deformed by introducing a slide 55 of the blow mold 51, able to move in the extension direction of the container precursor 13, into the cavity 53. The movable slide 55 is moved in this process from a first position, represented in FIG. 3a, to a second position, shown in FIG. 3b, while the blow mold 51 can remain closed during the process, but possibly also it is slightly open up to a maximum of 1 mm, or 0.3 mm to 0.5 mm. In the present exemplary embodiment, the parts 57 of the blow mold 51 defining the shape of the side wall 33 of the container precursor 13 are not moved and/or their position relative to each other is not changed (therefore being designated nonmoving parts 57 in the following).

[0086] The end face of the movable slide 55 is concave and defines in the first position substantially the shape of the bottom 22 of the container precursor 13. The bottom 22 of the container precursor 13 extends in the first position of the movable slide 55 by at most 10 or 5 or at least 1 or 2 material thicknesses (especially thicknesses of the material of the side wall 33 of the container precursor 13) to the side beyond the movable slide 55. The nonmoving parts 57 for this purpose may have an indentation 62 in a first section 59 adjoining the movable slide 55 in the first position and extending along the entire circumference of the movable part 55. The first section 59 is bordered by a second section 61, which determines the shape of the finished container 11, being visible when the container 11 is stored on a flat surface. The average extension of the indentation 62 in the direction of movement (i.e., from the first position in the direction of the second position) of the movable slide 55 and/or in the direction of the longitudinal axis of the container precursor 13 can advantageously correspond to at least 20, 30 or 40 and/or at most 80, 70 or 60 percent of the distance traveled by the movable slide 55 between the first position and the second position.

[0087] If the movable slide 55 is moved from the first position into the cavity 53 in the second position, the bottom 22 of the container precursor 13 will be shoved into the interior of the container precursor 13 bounded by the side wall 33 and the bottom 22. The region of the side wall of the container precursor 13 adjoining the bottom 22 of the container precursor 13, being the partial region of the side wall 33 of the container precursor 13 situated in the indentation 62 in the first position of the movable slide 55, will be everted or reversed, become attached at the side to the movable slide 55, and finally form a partial region of the undercut container bottom 21 of the finished container 11. This portion of the container bottom 21 adjacent to the formed edge 29, which at the same time forms the standing area of the container 11, is oriented parallel to the partial region of the container side wall 31 of the container 11 bordering on the edge 29 and advisedly firmly joined to it by the action of heat. Hence, the edge 29, or the standing area of the container 11, is formed from a partial region of the side wall 33 of the container precursor 13. For the stripping of the container 11 from the mold, the movable slide 55 must be moved from its second position back to the first position far enough so that the movable slide 55 is disengaged from the container 11.